Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/10/13


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
838 PM MDT TUE JUL 9 2013 .UPDATE...ONLY ISOLATED CONVECTION OVER THE MOUNTAINS AND SLIGHTLY MORE OVER THE FAR NORTHEASTERN PLAINS WHERE BETTER MOISTURE EXISTS. STILL LOOKING FOR THE NORTHEAST PUSH LATER TONIGHT TO SPREAD BETTER MOISTURE WEST UP AGAINST THE FOOTHILLS AND MOUNTAINS. LOOKING AT RECENT MODELS...MORE SEEM TO BE COMING IN LINE WITH THE 18Z GFS WITH SOME PRECIP OVER THE FAR NORTHEAST CORNER AFTER MIDNIGHT. NOW THE 00Z NAM, AND THE RECENT RAP AND HRRR MODELS PAINTING QPF OUT THERE. ACTUALLY, THE HRRR IS SPREADING THE QPF BACK WEST TOWARD THE NORTHERN FOOTHILLS EARLY TOMORROW MORNING. FOR NOW...WILL KEEP THE SLIGHT CHANCE OF PRECIP OVER THE NORTHEAST CORNER AS NO MODEL EXCEPT HRRR EVEN PICKED UP ON THE CONVECTIVE CLUSTER OVER SW NEBRASKA. WILL CONTINUE TO WATCH EVOLUTION OF CONVECTION AND THE FRONTAL PUSH. && .AVIATION...STILL DEALING WITH MULTIPLE OUTFLOW BOUNDARIES...BUT LOOKS LIKE WE`LL SETTLE INTO A NORTHERLY WIND INTO A NORTHEAST THEN SOUTHEAST LATER TONIGHT. NO MORE CONVECTION CURRENTLY EXPECTED THROUGH THE NIGHT WITH VFR CONDITIONS. LOOKING FOR AN ACTIVE DAY WEDNESDAY WITH SCATTERED THUNDERSTORMS AROUND THE DENVER AREA...AFFECTING BOTH AIRPORT OPERATIONS AND DEPARTURE/ARRIVAL GATES. SEVERE STORMS WITH LARGE HAIL AND GUSTY WINDS WILL BE POSSIBLE. && .PREV DISCUSSION... /ISSUED 555 PM MDT TUE JUL 9 2013/ UPDATE... AVIATION...BOUNDARIES GALORE ACROSS THE AREA...PRIMARILY FROM CONVECTION. ONE BOUNDARY WAS MOVING ACROSS PLAINS TOWARD THE WEST...APPEARS TO HAVE STALLED ACROSS WELD...EASTERN ADAMS AND EASTERN ARAPAHOE COUNTIES. ONE BOUNDARY CURRENTLY MOVING ACROSS DIA AND WILL MAINTAIN A NORTHWEST DIRECTION THERE THROUGH AROUND 02Z. MODELS STILL TRYING TO PUSH A NORTHEAST SURGE ACROSS THE AREA BETWEEN 02Z AND O5Z...STILL SEEMS REASONABLE FOR NOW. ONLY OTHER CHANGE TO CURRENT THINKING IS TO DROP THE MENTION OF THE STRATUS IN THE 12Z TO 15Z TIME FRAME. LATEST GUIDANCE NOT SHOWING ANY INDICATION OF THIS OCCURRING. DECENT CHANCE OF STORMS AFTER 19Z. AT THIS TIME IT DOES NOT APPEAR CEILINGS WILL BE LOWER THAN 7000 FEET AGL AT DEN AND APA. PREV DISCUSSION... /ISSUED 340 PM MDT TUE JUL 9 2013/ SHORT TERM...ISOLATED HIGH-BASED SHOWERS HAVE BEEN MOVING OVER THE MOUNTAINS AND GENERATING SOME GUSTY OUTFLOW WINDS OVER THE WESTERN AND SOUTHERN PARTS OF THE DENVER METRO AREA. SHOWERS AND BEEN DISSIPATING/EVAPORATING BEFORE MOVING OVER THE PLAINS. SHOULD SEE THIS ACTIVITY CONTINUE THROUGH ABOUT 01Z AND THEN DIMINISH. ACROSS THE REST OF THE PLAINS...NORTHERLY WINDS HAVE CONTINUED AHEAD OF A COLD FRONT WHICH WILL BRING LOW LEVEL MOISTURE ACROSS NORTHEAST COLORADO OVERNIGHT. BY TOMORROW MORNING...LOW LEVEL WINDS SHOULD HAVE VEERED TO THE SOUTHEAST AS HIGH PRESSURE DROPS OVER THE CENTRAL PLAINS. COLORADO WILL BE UNDER MODERATE WESTERLY FLOW ALOFT AS THE UPPER LEVEL RIDGE DROPS SOUTHWARD. A SHORT WAVE TROUGH EMBEDDED IN THE WESTERLY FLOW IS ALSO FORECAST FOR TOMORROW AFTERNOON. INGREDIENTS SHOULD ALL COME TOGETHER TOMORROW AFTERNOON FOR A SIGNIFICANT ROUND OF THUNDERSTORMS TO DEVELOP OVER THE MOUNTAINS AND FOOTHILLS THEN ROLL ONTO THE PLAINS. THERE WILL BE A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH LARGE HAIL AND STRONG WINDS. MODEL SOUNDINGS FOR TOMORROW AFTERNOON SHOW CAPE VALUES AROUND 1500 J/KG. PRECIPITABLE WATER VALUES SHOULD ALSO RISE BACK UP TO AROUND ONE INCH...SO LOCALLY HEAVY RAINS WILL ALSO BE POSSIBLE. AS THE EVENT IS DRIVEN BY A PASSING UPPER TROUGH...IT HAS THE POTENTIAL TO AFFECT A PRETTY GOOD AMOUNT OF THE FORECAST AREA BEFORE IT MOVES OUT TOMORROW EVENING. LONG TERM...STORM THREAT AND POTENTIAL FOR SOME SEVERE STORMS TO SHIFT EAST ACROSS THE PLAINS WEDNESDAY EVENING AS MID LEVEL QG LIFT ASSOCIATED WITH SHORTWAVE MOVES INTO KANSAS. STILL FAIRLY DECENT SHEAR ACROSS PLAINS...WEAKER NEAR THE URBAN CORRIDOR AS MODELS SHOW DENVER CYCLONE DISSIPATING AND SURFACE WINDS BECOMING WESTERLY. FORECAST SOUNDINGS SHOWING CAPES IN THE DENVER AREA AROUND 1000 J/KG THROUGH 03Z...WITH CLOSE TO 2000 J/KG OVER THE NORTHEAST CORNER. HAIL AND GUSTY WINDS WILL BE THE MAIN THREATS. WITH PRECIPITABLE WATER VALUES EXCEEDING AN INCH...SOME STORMS COULD PRODUCE BRIEF HEAVY RAINFALL. ACROSS THE MOUNTAINS AND FOOTHILLS...STORM CHANCES TO DECREASE DURING THE EVENING AS MID LEVEL SUBSIDENCE MOVES OVER THE AREA. STORMS OVER THE HIGH COUNTY TO PRODUCE GUSTY WINDS ALONG WITH BRIEF MODERATE RAINFALL. SHOULD SEE STORMS END ACROSS THE AREA AROUND MIDNIGHT WITH GRADUALLY CLEARING SKIES. ON THURSDAY...CENTER OF UPPER RIDGE SLOWLY MOVES ACROSS SOUTHERN COLORADO...LOCATED NEAR THE TEXAS AND OKLAHOMA PANHANDLES BY 00Z FRIDAY. WESTERLY FLOW ALOFT BECOMES MORE SOUTHWEST BY FRIDAY EVENING. URBAN CORRIDOR TO BE SLIGHTLY DRIER DUE TO THE COMBINATION OF WEAK MID LEVEL SUBSIDENCE AND DOWNSLOPE FLOW IN AND NEAR FOOTHILLS. BETTER MOISTURE TO RESIDE ACROSS THE NORTHEAST PLAINS ALONG WITH WEAK SHEAR. THUS BEST CHANCE FOR STORMS TO BE EAST OF THE URBAN CORRIDOR DURING THE AFTERNOON AND EVENING...WITH BRIEF MODERATE RAIN AND GUSTY WINDS. TEMPERATURES LOOK TO BE NEAR NORMAL ACROSS THE PLAINS...WITH HIGHS IN THE MIDDLE 90S. FOR FRIDAY...MODELS SHOW SOUTHWEST FLOW ALOFT PREVAILING WITH THE CENTER OF THE RIDGE OVER THE TEXAS AND OKLAHOMA PANHANDLES. SUBTROPICAL MOISTURE TO INCREASE ACROSS THE AREA...MAINLY ACROSS THE MOUNTAINS. THIS WILL PROVIDE FOR AN INCREASING CHANCE FOR THUNDERSTORMS. BOTH THE NAM AND GFS HAVE BACKED OFF ON THE TIMING OF THE STORMS...ESPECIALLY ACROSS THE PLAINS. MADE ADJUSTMENTS ACCORDINGLY. WITH THE MODEST MOISTURE INCREASE...THERE IS SOME POTENTIAL FOR THE STORMS TO PRODUCE BRIEF HEAVY RAIN. LITTLE CHANGE IN TEMPERATURES EXPECTED ACROSS THE PLAINS...WITH HIGHS IN THE MIDDLE 90S. ON SATURDAY...SOUTHWEST FLOW ALOFT CONTINUES...ALLOWING FOR A BIT MORE SUBTROPICAL MOISTURE TO SPREAD NORTHEAST ACROSS THE AREA WHICH SHOULD PROVIDE A BETTER CHANCE OF THUNDERSTORMS. HEAVY RAIN THREAT TO INCREASE DUE TO THE INCREASE IN MOISTURE. STORM MOTION APPEARS QUICK ENOUGH TO PRECLUDE ANY FLOOD THREAT AT THIS TIME. TEMPERATURES TO BE COOLER DUE TO CLOUD COVER WITH HIGHS AROUND 90 DEGREES ACROSS THE PLAINS. FOR THE LATER DAYS...SUNDAY THROUGH TUESDAY: SOUTHWEST FLOW ALOFT TO CONTINUE SUNDAY KEEPING THE INFLUX OF SUBTROPICAL MOISTURE ACROSS THE AREA AND A GOOD CHANCE FOR THUNDERSTORMS. THREAT FOR HEAVY RAIN TO CONTINUE. AIRMASS SLIGHTLY COOLER WITH HIGHS IN THE MIDDLE AND UPPER 80S OVER NORTHEAST COLORADO. FOR MONDAY AND TUESDAY...MODELS SHOW RIDGE REDEVELOPING NEAR THE FOUR CORNERS WITH THE FLOW ALOFT BECOMING WESTERLY. SUBTROPICAL MOISTURE TO GRADUALLY DECREASE ACROSS THE AREA... ESPECIALLY TUESDAY. SHOULD SEE THUNDERSTORM CHANCES DECREASE ALONG WITH A SLIGHTLY WARMER TEMPERATURES. THREAT FOR HEAVY RAIN WILL ALSO DECREASE. TEMPERATURES TO WARM TO NEAR NORMAL BY TUESDAY. AVIATION...OUTFLOW BOUNDARIES FROM WEAK CONVECTION OVER THE FOOTHILLS MAY CAUSE WINDS AT THE AIRPORT TO BRIEFLY SHIFT TO THE SOUTHWEST. BY 00Z...WINDS SHOULD RETURN TO A NORTHERLY DIRECTION AHEAD OF A MORE SUBSTANTIAL COLD FRONT EXPECTED TO PASS BEFORE 06Z. GUSTY NORTH WINDS WILL ACCOMPANY THE COLD FRONT AND THEN TRANSITION TO EASTERLY AND SOUTHEASTERLY DURING THE PRE-DAWN HOURS. MVFR CIGS MAY DEVELOP FOR A FEW HOURS AROUND SUNRISE. TOMORROW AFTERNOON LOOKS LIKE IT WILL BE ACTIVE WITH SCATTERED THUNDERSTORMS AROUND THE DENVER AREA...AFFECTING BOTH AIRPORT OPERATIONS AND DEPARTURE/ARRIVAL GATES. SEVERE STORMS WITH LARGE HAIL AND GUSTY WINDS WILL BE POSSIBLE. HYDROLOGY...SHOWERS THIS AFTERNOON HAVE BEEN HIGH-BASED AND FAST MOVING WITH ONLY LIGHT RAINFALL AMOUNTS. NO HYDROLOGY PROBLEMS EXPECTED THROUGH THE EVENING. FOR WEDNESDAY...MOISTURE LEVELS OVER THE FORECAST AREA WILL BE HIGHER WITH SOUTHEASTERLY AND EASTERLY WINDS ACROSS THE PLAINS. SHOWER ACTIVITY IS EXPECTED TO BE STRONGER AND SLOWER MOVING WITH THE POTENTIAL FOR SOME HEAVY RAINFALL. STORMS THAT FORM OVER BURN SCARS MAY CAUSE SOME PROBLEMS THROUGH THE AFTERNOON AND EVENING. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DANKERS LONG TERM....D-L UPDATE/AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
727 PM EDT TUE JUL 9 2013 .SYNOPSIS... A FEW SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL WILL AFFECT THE REGION AT TIMES THROUGH FRIDAY. AT THIS POINT...THE SHOWERS AND THUNDERSTORMS LOOK TO BE MOST WIDESPREAD ON THURSDAY. MAINLY DRY AND LESS HUMID WEATHER LOOKS FINALLY ARRIVE BY THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 7 PM UPDATE... ACTIVITY ACROSS THE REGION DIMINISHING WITH SUNSET. VERY LITTLE IN THE WAY OF A TRIGGER ACROSS THE STALLED FRONTAL BOUNDARY DRAPED FROM THE EASTERN GREAT LAKES REGION SOUTHEASTWARD THROUGH THE LOWER HUDSON RIVER VALLEY AND EAST PARALLEL TO THE SOUTH-SHORE OF NEW ENGLAND. HEIGHTS CONTINUING TO RISE WITH WARM AIR ADVECTION AHEAD OF AN APPROACHING TROUGH FOR WEDNESDAY INTO THURSDAY... OVERNIGHT ACTIVITY SHOULD BE SUPPRESSED...AND WITH LITTLE INSTABILITY...CONCEDED TO CHANCE POPS ACCORDINGLY. HRRR CONTINUES TO BE THE NEAR-TERM MODEL OF CHOICE. OTHERWISE...ECHO THE PREVIOUS FORECASTERS DISCUSSION OF LOW CLOUDS AND FOG BEING THE MAIN CONCERN FOR THE OVERNIGHT PERIOD. GREATEST CONFIDENCE OF AREAS IMPACTED BY RAINS EARLIER TODAY...AS WELL AS REGIONS ADJACENT TO BODIES OF WATER /COASTLINES/ WILL SEE DENSE FOG WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS WITH LIGHT SOUTHERLY WINDS. A DENSE FOG ADVISORY MAY BE NECESSARY. STALLED FRONTAL BOUNDARY SHOULD LIFT NORTH OVERNIGHT AS WINDS ABOVE THE BOUNDARY LAYER BECOME SOUTHWESTERLY AND WARM AIR ADVECTION PROCEEDS AHEAD OF THE APPROACHING TROUGH FOR WEDNESDAY. AS SUCH...WITH HIGH SURFACE MOISTURE CONTENT AND A WARMING AIRMASS ALOFT...SHOULD BE A MILD NIGHT WITH LOW TEMPERATURES AROUND THE UPPER 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... TOMORROW... A LOT OF UNCERTAINTY STILL IS IN PLACE FOR TOMORROW. UPPER LEVEL LOW OVER THE UPPER GREAT LAKES WILL CONTINUE THE TROUGH OVER THE REGION. QUICK MOVING SHORTWAVE WILL MOVE THROUGH THE FLOW ALLOWING FROM SOME SORT OF LIFT FOR THE REGION. HOWEVER LOOKING AT FORECAST GUIDANCE IT SEEMS THE AREA THAT MAY SEE THE BETTER POTENTIAL FOR STORMS WILL BE OUT WEST ACROSS THE CT VALLEY/ORH HILLS. THIS REGION WILL HAVE THE BETTER INSTABILITY ONCE THE LOW STRATUS DECK BREAKS UP. CURRENT BOUNDARY ACROSS THE REGION NOW WILL LIFT NORTHWARD AS A FORM OF A WARM FRONT WHEN THE SHORTWAVE APPROACHES. THIS WILL ALLOW FOR TEMPS TO WARM RIGHT BACK UP INTO THE MID TO UPPER 80S. BELIEVE THAT STORMS WILL MAINLY BE DIURNALLY DRIVE DURING THE DAY. WITH LACK OF SHEAR AND FLOW ALOFT BELIEVE THESE STORMS WILL BE NEARLY STATIONARY AND WITH PWATS IN THE 1.5 TO 2 INCHES...HEAVY DOWNPOURS WILL BE THE MAIN THREAT. CAPE VALUES SHOULD BE HIGHER THEN TODAY SO GUSTY WINDS MAY ALSO BE A POTENTIAL ONCE THUNDERSTORMS BEGIN TO COLLAPSE. STORMS SHOULD BEGIN TO WANE AFTER SUNSET ONCE DIURNAL HEATING IS LOST. TOMORROW NIGHT... AFTER A QUICK LULL IN CONVECTION MODELS ARE INDICATING THAT STORMS WILL FIRE UP OVERNIGHT AND LAST INTO THE THURSDAY. SYNOPTIC MODELS ARE STRUGGLING WITH PLACEMENT OF THE COLD FRONT AS THE GFS BRINGS IT ACROSS SNE FASTER THEN THE GENERAL TREND. ALSO AM HESITANT AS THESE SORT OF FRONTS HAVE THE TENDENCY TO STALL. HOWEVER IF THE FRONT MOVES TOWARDS THE REGION LATE TOMORROW NIGHT INTO THURSDAY MORNING THEN THE OVERNIGHT HOURS MAY BE ACTIVE. FORECAST GUIDANCE SHOWS ELEVATED INSTABILITY ACROSS THE REGION AS SHOWALTERS ARE -2C COMBINED WITH DEEP MOISTURE AND A SOURCE OF LIFT WHICH COULD HAVE STORMS FIRING OVERNIGHT. EXACT COVERAGE AND PLACEMENT IS STILL UNKNOWN AS THE TIMING IS THE OVERALL QUESTION. HOWEVER MAIN THREAT APPEARS TO BE HEAVY DOWNPOURS. HAVE CONTEMPLATED WITH THE ISSUANCE OF A FLASH FLOOD WATCH BUT HAVE COLLABORATION WITH SURROUND OFFICES DECIDED TO HOLD OFF AS THERE IS STILL A LOT OF UNCERTAINTY. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HEADLINES... * HEAVY RAIN AND POTENTIAL FLOODING FOR THURSDAY * RAINS LINGER TO THE SOUTHEAST INTO FRIDAY * A RETURN OF MORE SEASONABLE WEATHER INTO THE WEEKEND AND EARLY WEEK */OVERVIEW AND MODEL CONSENSUS... THOUGH MODELS AGREE UPON A BROAD RIDGING PATTERN EVOLVING ACROSS THE CONUS...THEY REMAIN AT ODDS AND STRUGGLE WITH HANDLING ENERGY ALONG THE NORTHERN PERIPHERY OF THE RIDGE. CONSEQUENTIALLY...RUN-TO-RUN CONSISTENCY HAS BEEN POOR AS OF LATE WITH HANDLING THE EVOLUTION OF THE MID- TO UPPER-LEVEL ENERGY DIVING SOUTHEAST OUT OF CANADA AND ACROSS THE NORTHEASTERN CONUS...POTENTIALLY EVOLVING INTO A CLOSED LOW THAT RETROGRADES SOUTH AND WEST. HPC/WPC MAINTAINS CONTINUITY WITH THEIR FORECAST...GOING WITH A 09.0Z ENSEMBLE BLEND...NOTING THE UNCERTAIN TRACK OF TROPICAL STORM CHANTAL. WILL FOLLOW SUIT INCORPORATING THEIR FORECAST INTO A BLEND OF THE 09.12Z FORECAST GUIDANCE. */DAY-TO-DAY DETAILS... */THURSDAY INTO THURSDAY NIGHT... SURFACE COLD FRONT SLOWED ACROSS SOUTHERN NEW ENGLAND AGAINST RIDGING OF HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL BE FORCED OFFSHORE DURING THE EVENING HOURS AND OVERNIGHT AS THE MID- TO UPPER- LEVEL TROUGH AXIS PUSHES SOUTHEAST OUT OF CANADA INTO THE NORTHEAST CONUS. FEEL 09.12Z GFS IS TOO FAST WITH THIS FEATURE. CHANCE TO LIKELY POPS WARRANTED THURSDAY WITH DEEP-LAYER FORCING COUPLED WITH THE RIGHT-ENTRANCE REGION OF THE UPPER-LEVEL JET... DIMINISHING INTO THE EVENING WITH THE COLD FRONT PUSHING OFFSHORE. WITH CERTAINTY...COLD POOL WILL PUSH SOUTHEAST IMPROVING MID-LEVEL LAPSE RATES AS UNI-DIRECTIONAL SOUTHWESTERLY SHEAR INCREASES TO AROUND 30 KTS ACROSS THE REGION. SO WHILE ELEVATED INSTABILITY IS PLAUSIBLE...BOUNDARY LAYER DESTABILIZATION IS QUESTIONABLE AS ACTIVITY COULD BE ONGOING DURING THE MORNING FORCED BY STRONG LOW- LEVEL CONVERGENCE. CLOUDS IMPEDING DIURNAL HEATING. LESSER CONFIDENCE OF A SEVERE WEATHER THREAT...GREATER CONCERN FOR FLOODING WITH 2-INCH PWATS AND AFOREMENTIONED DEEP-LAYER FORCING. GREATER CHANCE FOR FLOODING ACROSS CENTRAL AND EASTERN PORTIONS OF SOUTHERN NEW ENGLAND...FOCUSING ON THE MORNING INTO MIDDAY PERIOD. */FRIDAY INTO NEXT WEEK... IT IS NOT ENTIRELY CLEAR HOW THE MID- TO UPPER-LEVEL ENERGY ASSOCIATED WITH THE ACTIVITY ON THURSDAY WILL EVOLVE. DETERMINISTIC GFS/ECMWF SOLUTIONS EXHIBIT ATTENDANT ENERGY TO BIFURCATE FROM THE NORTHERN STREAM...BECOMING A CLOSED LOW AND RETROGRADING SOUTH AND WEST WITH THE MEAN FLOW AROUND THE BROAD RIDGING ACROSS THE CONUS. QUITE ODD FOR AN EARLY SUMMERTIME PATTERN. THAT BEING SAID...SURFACE OUTCOMES REMAIN UNCERTAIN. IT APPEARS HIGH PRESSURE OUT OF THE GREAT LAKES REGION WILL USHER MORE SEASONABLE CONDITIONS BACK INTO THE REGION WITH NORTHERLY WINDS...AS A FRONTAL BOUNDARY REMAINS STALLED OFFSHORE. COULD SEE THE CHANCE OF SHOWERS FOR FAR SOUTHEAST SOUTHERN NEW ENGLAND INITIALLY. THIS HIGH WILL TRANSITION EAST RESULTING IN THE RETURN USHERANCE OF SOUTHERLY FLOW AND PERHAPS RENEWED CHANCES OF SHOWERS AND THUNDERSTORMS AS HEAT AND HUMIDITY GRADUALLY BUILD BACK OVER THE REGION. LITTLE FORCING WITHIN THE MID- TO UPPER-LEVELS IS APPARENT...SO ANY SHOWERS OUTPUTTED BY FORECAST GUIDANCE APPEARS TO BE A RESULT OF LOCALIZED CONVERGENCE LIKELY ALONG SEA-BREEZE BOUNDARIES /AIR-MASS THUNDERSTORMS/. CHANCE TO SLIGHT CHANCE POPS ACROSS THE INTERIOR... LOW CONFIDENCE SEVERE WEATHER THREATS. WILL KEEP CONDITIONS CLOSE TO SEASONABLE. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...TODAY THROUGH WEDNESDAY... MODERATE CONFIDENCE ON TRENDS...LOW CONFIDENCE ON TIMING. SHRA/TSRA DIMINISHING. MAIN CONCERN FOR OVERNIGHT WILL BE FOG WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS. THOSE TERMINALS CLOSEST TO BODIES OF WATER AND/OR IMPACTED BY DAYTIME RAINS IN THE GREATEST RISK. LOW IFR-LIFR CIGS TO IMPACT ALL TERMINALS. TRENDS SHOULD IMPROVE TOMORROW AS WINDS INCREASE OUT OF THE SOUTH-SOUTHWEST IN RESPONSE TO AN APPROACHING COLD FRONT. BY MIDDAY...ANTICIPATING SHRA/TSRA TO BREAK OUT OVER THE MID-HUDSON RIVER VALLEY REGION AND PRESS EASTWARD. HAVE VCTS FOR THE AFTERNOON HOURS FOR WESTERN TERMINALS FOR NOW. DIRECT IMPACTS BY TSRA WILL LIKELY RESULT IN LOW-VFR/MVFR CIGS WITH MVFR/IFR VSBYS. LOW CONFIDENCE ON SEVERE WEATHER IMPACTS...MAIN THREAT WILL BE +RA. SHRA/TSRA ACTIVITY MOVES WEST TO EAST WITH THE FLOW...POSSIBLY DIMINISHING INTO THE EVENING PERIOD...MODERATE CONFIDENCE. COLD FRONT WILL SLOW IN ITS APPROACH EAST. WHILE WESTERN TERMINALS MAY IMPROVE GRADUALLY INTO THE EVENING PERIOD...FEEL EASTERN TERMINALS WILL REMAIN SOCKED IN WITH THE POTENTIAL FOR FOG. TODAY...MVFR ACROSS MUCH OF THE REGION WITH IFR ACROSS THE CAPE. BOUNDARY IS SITUATED GENERALLY FROM KACK-KMMK-KAQW. NORTH AND EAST OF THE BOUNDARY IS IN EASTERLY TO NORTHEAST FLOW WHILE SOUTH AND WEST OF THE BOUNDARY IS DUE SOUTH. EXPECT THE CT VALLEY TO BREAK OUT INTO VFR HOWEVER EVERYWHERE ELSE SHOULD STAY SOCKED IN. VCTS CONDITIONS ARE BEST FOR PVD/BAF/BDL AS TSRA ARE FIRING ACROSS THE BOUNDARY. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP CONDITIONS DOWN TO IFR FOR TONIGHT...HOLDING OFF ON LIFR VSBYS. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. GOING WITH PERSISTENCE TRENDS IN REPLICATING THE PREVIOUS EVENINGS OUTCOME. HAVE A MENTION OF VCTS FOR THE WEDNESDAY AFTERNOON PERIOD. OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE THURSDAY INTO THURSDAY NIGHT... SHRA/TSRA...BETTER CHANCES DURING THE MORNING INTO MIDDAY HOURS PUSHING NW TO SE. MVFR/IFR CIGS WITH MVFR/IFR VSBYS...CONDITIONS POTENTIALLY LOWER WITH +RA AND ACROSS SE COASTAL TERMINALS WITH FOG. SW WINDS BACKING OUT OF THE W/NW WITH COLD FRONTAL PASSAGE. FRIDAY INTO SUNDAY... SHRA/TSRA MAY LINGER ACROSS FAR SE COASTAL TERMINALS DURING THE INITIAL PERIOD WITH MVFR-IFR IMPACTS AT LOWEST. OTHERWISE PREVAILING VFR WITH NORTHERLY WINDS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...HIGH CONFIDENCE. TODAY THROUGH WEDNESDAY... WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT CRITERIA THROUGH TOMORROW. AS WINDS SHIFT BACK TO S-SW AND PICK UP DURING WED AFTERNOON...WITH GUSTS UP TO 20 KT...SEAS MAY BUILD BACK UP TO AROUND 5 FT ON THE SOUTHERN WATERS. SMALL CRAFT ADV MAY BE NEEDED THEN. SEEMS THAT WNA GUIDANCE WAS OVERDOING THE SEAS AGAIN SO HAVE UNDERCUT THEM. EXPECT REDUCED VSBYS TONIGHT INTO TOMORROW MORNING FROM FOG. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ON WED INTO WED NIGHT. OUTLOOK...THURSDAY INTO SUNDAY...MODERATE CONFIDENCE. THURSDAY INTO THURSDAY NIGHT... RAIN AND POSSIBLE THUNDERSTORMS WILL INCREASE TOWARDS THE WATERS DURING THE DAY AND PREVAIL INTO THE EVENING ALONG AND AHEAD OF AN APPROACHING COLD FRONT. STORMS MAY BE STRONG WITH GALE FORCE GUSTS...OTHERWISE PREVAILING SW WINDS AHEAD OF THE COLD FRONT BACKING OUT OF THE W/NW LATE. SEAS IN EXCESS OF 5 FEET ON THE OUTER WATERS. VISIBILITY IMPACTS WITH HEAVY RAIN ANTICIPATED. FRIDAY INTO SUNDAY... RAIN AND POSSIBLE THUNDERSTORMS WILL LINGER FOR THE INITIAL PERIOD SLOWLY MOVING INTO THE ATLANTIC. HIGH PRESSURE BUILDING FROM THE WEST WILL RESULT IN NORTHERLY FLOW. COULD SEE GUSTS UP TO AROUND 20 KTS WHICH WOULD ALLOW SEAS ON THE OUTER WATERS TO REMAIN AT OR ABOVE 5 FEET. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...DUNTEN/SIPPRELL NEAR TERM...DUNTEN/SIPPRELL SHORT TERM...DUNTEN LONG TERM...SIPPRELL AVIATION...DUNTEN/SIPPRELL MARINE...DUNTEN/SIPPRELL
AREA FORECAST DISCUSSION
NWS ALBANY NY
1121 AM EDT MON JUL 8 2013 .SYNOPSIS... A STRONG MID LEVEL DISTURBANCE WILL MOVE INTO OUR REGION THIS AFTERNOON FOCUSING ANOTHER ROUND OF NUMEROUS SHOWERS AND THUNDERSTORMS...SOME OF WHICH COULD CONTAIN HEAVY RAINFALL. THIS SYSTEM WILL MOVE TO OUR EAST ALLOWING SLIGHTLY DRIER AIR TO MOVE IN ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A FLASH FLOOD WATCH CONTINUES FOR OUR ENTIRE COUNTY WARNING AREA (CWA) FROM 1100 AM EDT THROUGH MIDNIGHT. AS OF 11 AM EDT...THE RADAR HAS BEEN QUIET AND POPS AND WEATHER HAVE BEEN RETRENDED. CLOUDS MAY LIMIT THE COVERAGE TODAY...BUT THE LATEST HIRESWRF AND HRRR DUE SHOW COVERAGE INCREASING IN THE AFTERNOON WITH THE CLOSE LOW APPROACHING FROM W-CNTRL PA. THIS LOW HAS A NEUTRAL TILT...WHICH CSTAR RESEARCH FROM ALY HAS SHOWN A THREAT WITH FLOODING AND STRONG TO SEVERE THUNDERSTORMS. HOWEVER...THE AMOUNT OF SFC HEATING MAY LIMIT THIS THREAT QUITE A BIT...ALSO THE CLOSED/CUT-OFF LOW MAY OPEN...AND BECOME AN OPEN WAVE LATER TODAY. THE LATEST PWAT FROM THE KALB SOUNDING HAS FALLEN CONSIDERABLY FROM 00Z FROM 2.18" /ABOUT AS HIGH AS YOU GET IT/...AND IT HAS SUNK TO 1.42 INCHES WITH SLIGHTLY DRIER AIR IN THE WAKE OF THE SFC TROUGH LAST NIGHT. THE AMOUNT OF CLOUD COVER FROM THE CAPITAL REGION NORTH AND WEST MAY LIMIT SIGNIFICANT THUNDERSTORM AND SHOWER COVERAGE. LOCATIONS SOUTH AND EAST WOULD BE THE MOST VULNERABLE FOR STRONG CONVECTION. THE SVR THREAT LOOKS LESS WITH VERY WEAK LAPSE RATES...AND WEAK DEEP SHEAR. FZL HEIGHTS ARE HIGH AROUND 15 KFT AGL. WE WILL CONTINUE TO MONITOR FOR SOME PULSE TSRAS. TEMPS MAY NEED TO BE CURTAILED DOWNWARD LATER TOO. SOME SLIGHT TWEAKS DOWNWARD FROM DONE OVER THE SRN DACKS AND LAKE GEORGE REGION WITH 70S TO NEAR 80F. MID AND U80S ARE POSSIBLE OVER THE VALLEYS AND HILLS FROM THE CAPITAL REGION SOUTH AND EAST. MORE ON THE HYDRO/FLASH FLOOD DISCUSSION BELOW... THE BIGGER CONCERN WITH THE STORMS WOULD BE EXCESSIVE RAINFALL. PWAT VALUES WHILE DOWN A LITTLE FROM LAST EVENING...WILL STILL RANGE BETWEEN 1.75-2.00 INCH...UP TO 3 STANDARDS ABOVE NORMAL. THE FREEZING LEVEL IS FORECAST TO DROP A LITTLE FROM 15,000 TO ABOUT 13,000 BY DAY/S END BUT STILL PLENTY HIGH FOR EFFICIENT RAIN FORMATION IN THE CLOUDS (WARM CLOUD PROCESSES). ALSO...MOST OF OUR AREA HAS EXCESSIVE MOIST SOILS DUE TO THE RASH OF HEAVY RAINFALL DURING THE PAST SIX WEEKS. WE HAVE PLACED OUR ENTIRE REGION IN A FLASH FLOOD WATCH FROM MIDDAY THROUGH THE EVENING HOURS. FLASH FLOOD GUIDANCE (FFG) VALUES ARE QUITE LOW...RANGING FROM 1-2 INCHES FOR HOURLY RAINFALL RATES ACROSS THE REGION. THE BOTTOM LINE...IT WOULD NOT TAKE A WHOLE LOT OF RAIN TO INDUCE POTENTIAL FLASH FLOODING TODAY...ESPECIALLY IN HERKIMER COUNTY...WHERE A PLETHORA OF FLASH FLOODS HAVE ALREADY ENSUED IN THE PAST WEEKS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE UPPER LEVEL LOW WILL STILL BE WORKING ACROSS OUR EASTERN REGIONS THROUGH THE EVENING HOURS WITH ON GOING SHOWERS AND THUNDERSTORMS. THESE SHOULD WANE LATER OVERNIGHT AND TOWARD DAYBREAK MOST OF THE REGION SHOULD BE PRECIPITATION FREE ONCE MORE...ALTHOUGH SOME SHOWERS MIGHT LINGER TO THE EAST OF THE HUDSON VALLEY. A TRAILING WEAK COLD FRONT LOOKS TO CROSS THE REGION THROUGH THE NIGHT. THE AIR BEHIND THIS FRONT WILL BE ONLY VERY SLIGHTLY COOLER IN THE MID LEVELS AND DRIER TOO. TUESDAY...WITH WEAK SUBSIDENCE AND THE SLIGHT DRYING...IT LOOKS AS IF THE SHOWER AND THUNDERSTORM COVERAGE WILL BE MUCH LOWER. STILL...THERE WILL STILL ENOUGH LOW LEVEL MOISTURE AROUND FOR INSTABILITY AND A RANDOM POP-UP THUNDERSTORM OR TWO DURING THE AFTERNOON..ESPECIALLY IN OUR SOUTHERN ZONES. WITH MORE SUNSHINE THAN MONDAY...RESULTANT HIGH TEMPERATURES WILL ACTUALLY BE A FEW POINTS HIGHER...ESPECIALLY IN THE VALLEYS WHERE 85-90 WILL COMMON WHILE THE HIGHER TERRAIN WILL RANGE FROM THE 80-85. A LIGHT WEST WIND WILL BECOME SOUTH BY LATE IN THE DAY. A SLIGHTLY STRONGER COLD FRONT IS POISED TO SLIP FROM THE GREAT LAKES AND HEAD TOWARD OUR REGION LATER TUESDAY NIGHT INTO WEDNESDAY. THIS FEATURE WILL TAKE ITS TIME APPROACHING AND ESPECIALLY CLEARING OUR REGION. IT LOOKS MAINLY DRY TUESDAY NIGHT (BUT DID KEEP 20 POPS FOR SHOWER OR THUNDERSTORM). BY WEDNESDAY...THE CHANCES WILL RAMP UP AGAIN AS THE FRONT NEAR AND THE ATMOSPHERE BECOMES MORE UNSTABLE. THE TIMING OF THE FRONT WILL HELP DETERMINE WHETHER OR NOT WE COULD BE LOOKING AT A POTENTIAL SEVERE WEATHER EVENT. RIGHT NOW...IT APPEARS THAT THE ACTUAL FRONT WILL NOT WORK ACROSS THE REGION UNTIL LATER WEDNESDAY NIGHT OR EARLY THURSDAY. WE WILL HAVE PLENTY OF TIME TO MONITOR THESE TRENDS. WEDNESDAY...AHEAD OF THE FRONT...TEMPERATURES WILL BE UNCOMFORTABLY WARM AND HUMID REACHING NEAR 90 IN THE MID HUDSON VALLEY...MID TO UPPER 80S MOST OTHER PLACES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MEDIUM RANGE MODELS (GFS/ECMWF) ARE NOW OFFERING SOME HOPE THAT MUCH OF THE LONG TERM PERIOD MAY BE RELATIVELY QUIET WEATHERIZE AND NOT AS HUMID. THE FORECAST FOR THE MAIN WEATHER FEATURES CALLS FOR THE COLD FRONT TO SHIFT SOUTH OF THE REGION EARLY ON THURSDAY... RESULTING IN MAINLY DRY WEATHER BY LATE IN THE DAY. THE UPPER LEVEL TROF THAT PUSHED THIS FRONT THROUGH IS THEN FORECAST TO CLOSE OFF/CUTOFF WELL TO THE SOUTHWEST OF THE REGION (OVER THE CENTRAL AND SOUTHERN APPALACHIANS) BY SATURDAY...AND THEN CONTINUE RETROGRADING WESTWARD DURING THE REST OF NEXT WEEKEND. AT THE SAME TIME THE RIDGE OVER THE WESTERN ATLANTIC WILL BUILD WESTWARD. THE RESULT OF ALL THIS IS THAT ONCE THE MOISTURE ASSOCIATED WITH FRONTAL BOUNDARY MOVES THROUGH...IT WILL HAVE A HARD TIME RETURNING NORTHWARD UNTIL THE RIDGE BUILDS WESTWARD AND THE SOUTHWEST FLOW AROUND IT BRINGS THE MOISTURE NORTHWARD AGAIN. HOWEVER...THIS IS NOT FORECAST TO HAPPEN UNTIL EARLY NEXT WEEK...SO THE PERIOD FROM THURSDAY NIGHT THROUGH SUNDAY IS GENERALLY FORECAST TO BE DRY BY BOTH THE GFS AND ECMWF. CONSIDERING THE WET PATTERN WE HAVE BEEN IN LATELY AND THAT THIS IS THE FIRST TIME BOTH MODELS SEEM TO INDICATE THE POSSIBILITY OF A DRY PERIOD...WILL NOT COMPLETELY REMOVE PCPN FROM THE FORECAST FOR NOW UNTIL LATER RUNS ALSO SUPPORT THIS DRIER PATTERN. AS THE FRONT SAGS SOUTH ON THURSDAY...HAVE FORECAST DECREASING POPS DURING THE DAY...THE DRY CONDITIONS THURSDAY NIGHT. ONLY A SLIGHT CHANCE FOR A SHOWER ON FRIDAY AND FRIDAY NIGHT...THEN A 30 PERCENT OF SHOWERS SATURDAY THROUGH SUNDAY WITH THUNDERSTORMS ALSO POSSIBLE SUNDAY AFTN/EVE. TEMPS WILL NOT BE AS WARM AS RECENTLY AND DEWPOINTS WILL ALSO BE 5 TO 10 DEGREES LOWER THAN RECENTLY. HIGHS THURSDAY WILL BE IN THE UPPER 70S TO MID 80S...MID 70S TO LOWER 80S FRIDAY...UPPER 70S TO MID 80S SATURDAY AND SUNDAY. LOWS THURSDAY AND FRIDAY NIGHTS WILL BE IN THE MID 50S TO MID 60S...AND UPPER 50S TO MID 60S SATURDAY NIGHT. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... AS AN UPPER LEVEL LOW TRACKS BY TO THE SOUTH OF THE REGION... EXPECT SCT TO NUMEROUS SHOWERS/TSTMS EXPECTED TO DEVELOP AGAIN THIS AFTERNOON...BUT AS WITH RECENT DAYS...TIMING AND LOCATION OF SHOWERS IS NOT POSSIBLE AT THIS TIME SO WILL ONLY FORECAST VCSH FOR NOW BETWEEN 08/16Z AND 09/01Z. WHERE SHOWERS/TSTMS DO OCCUR...WOULD EXPECT MVFR TO POSSIBLY IFR CIGS/VSBYS. OTHERWISE...HAVE FORECAST VFR CONDITIONS AT THE KALB/KGFL/KPOU/KPSF TAF SITES THROUGH LATE THIS EVENING. AFT AROUND 06Z TUESDAY...HAVE FORECAST SOME MVFR FOG AT KGFL AND KPSF. WINDS WILL BE CALM OR LIGHT AND VARIABLE THROUGH MID MORNING...THEN THEN BECOMING WEST-SOUTHWEST LATER ON TODAY AT SPEEDS OF 8 KTS OR LESS...THEN LIGHT AND VARIABLE AGAIN TONIGHT. OUTLOOK... TUE...MAINLY VFR. SCT -SHRA/-TSRA. WED...VFR/MVFR/IFR DUE TO SCT TO NUM -SHRA/-TSRA. THU-FRI...MAINLY VFR. SCT PM -SHRA/-TSRA. MVFR/IFR OVERNIGHT FOG POSSIBLE TUE-FRI. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SHOWERS AND THUNDERSTORMS WILL BECOME NUMEROUS ONCE MORE THIS AFTERNOON AND EARLY EVENING. THERE WILL BE LESS COVERAGE ON TUESDAY WITH MANY PLACES PERHAPS NOT RECEIVING ANY MEASURABLE RAINFALL. HOWEVER...MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED WEDNESDAY. NORMAL RH RECOVERIES EACH NIGHT BETWEEN 80 TO 100 PERCENT WILL ALLOW FOR WIDESPREAD DEW FORMATION. DAYTIME RH VALUES WILL GENERALLY BE IN THE 40 TO 60 PERCENT RANGE. && .HYDROLOGY... A FLASH FLOOD WATCH HAS BEEN ISSUED FOR OUR ENTIRE HSA FROM 1100 AM EDT THROUGH MIDNIGHT. THIS IS THE RESULT OF AN UPPER LEVEL LOW PRESSURE MOVING ACROSS THE REGION WITH ABOVE NORMAL PWAT VALUES. THE MOHAWK RIVER AT UTICA CONTINUES TO EXPERIENCE MINOR FLOODING. THE RIVER AND CREEK FLOWS NEAR THE WEST CENTRAL MOHAWK RIVER ARE EXPECTED TO GRADUALLY RECEDE INTO THE WEEKEND...UNLESS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OCCUR OVER OR NEAR THE BASIN. WHILE THE AVERAGE BASIN RAINFALL FORECAST INDICATED LESS THAN AN INCH OF RAIN TO FALL THROUGH THIS EVENING...THE COMBINATION OF MOIST SOILS...THE SLOW MOVING NATURE OF THE THUNDERSTORMS TODAY AND A VERY MOIST AIRMASS STILL IN PLACE WITH PWATS IN THE 1.33-1.75 INCHES...HAS PROMPTED THE FLASH FLOOD WATCH. 1-HR FLASH FLOOD GUIDANCE REMAINS UNUSUALLY LOW...IN THE 1-2 INCH RANGE. ANY THUNDERSTORM TODAY WOULD BE CAPABLE OF PRODUCING LOCALIZED RAINFALL AMOUNTS OF AN INCH OR BETTER IN HOUR OR LESS TIME AND THEREFORE THE NEED FOR THE WATCH. THUNDERSTORMS LOOK TO DIMINISH TONIGHT. TUESDAY...MUCH OF THE REGION COULD RECEIVE A BREAK IN THE ACTION...BUT A STRAY SHOWER OR THUNDERSTORM CANNOT BE ENTIRELY RULED...ESPECIALLY TO THE SOUTH OF ALBANY. PWATS LOOK TO DROP A LITTLE...DOWN TO AROUND 1.5 INCHES OR LITTLE LESS TO THE NORTH OF ALBANY. UNFORTUNATELY...A SLIGHTLY STRONGER COLD FRONT WILL APPROACH THE REGION WEDNESDAY REIGNITING THE THREAT OF SHOWERS AND THUNDERSTORMS INTO EARLY EARLY THURSDAY. WE MIGHT FINALLY CATCH A LITTLE MORE SUBSTANTIAL BREAK WITH POSSIBLE DRY WEATHER FRIDAY LASTING INTO THE BEGINNING OF THE WEEKEND. WHILE ADDITIONAL FLOODING IS NOT ANTICIPATED ON ANY MAIN STEM RIVER POINTS...LOCALLY SHARP RISES ARE POSSIBLE DUE TO ANY CONVECTION THAT MAY OCCUR OVER THE NEXT SEVERAL DAYS...ESPECIALLY FOR THOSE POINTS THAT ARE MORE FLASHIER IN NATURE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH THIS EVENING FOR CTZ001-013. NY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NYZ032-033-038>043- 047>054-058>061-063>066-082>084. MA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MAZ001-025. VT...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...HWJIV/WASULA NEAR TERM...HWJIV/WASULA SHORT TERM...HWJIV LONG TERM...GJM AVIATION...GJM FIRE WEATHER...HWJIV HYDROLOGY...HWJIV/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1031 AM EDT MON JUL 8 2013 .SYNOPSIS... A STRONG MID LEVEL DISTURBANCE WILL MOVE INTO OUR REGION THIS AFTERNOON FOCUSING ANOTHER ROUND OF NUMEROUS SHOWERS AND THUNDERSTORMS...SOME OF WHICH COULD CONTAIN HEAVY RAINFALL. THIS SYSTEM WILL MOVE TO OUR EAST ALLOWING SLIGHTLY DRIER AIR TO MOVE IN ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A FLASH FLOOD WATCH CONTINUES HAS FOR OUR ENTIRE COUNTY WARNING AREA (CWA) FROM 1100 AM EDT THROUGH MIDNIGHT. AS OF 1030 AM EDT...THE RADAR HAS BEEN QUIET AND POPS AND WEATHER HAVE BEEN RETRENDED. CLOUDS MAY LIMIT THE COVERAGE TODAY...BUT THE LATEST HIRESWRF AND HRRR DUE SHOW COVERAGE INCREASING IN THE AFTERNOON. AN UPPER AIR LOW...THE SAME ONE THAT CAUSED FLOODING PROBLEMS LAST WEEK...IS MOVING BACK TOWARD OUR REGION FROM WESTERN PA. THIS LOW PRESSURE WILL PROVIDE ASCENT (ALBEIT WEAK) AND ALSO COOL THE MID LEVELS OF THE ATMOSPHERE DOWN A LITTLE. THIS WILL GENERATE MORE SHOWERS AND THUNDERSTORMS...BECOMING NUMEROUS IN MOST PLACES BY AFTERNOON. INSTABILITY WILL BE SIMILAR TO YESTERDAY...WITH MUCAPES AROUND 1500 J/KG. HOWEVER...THE WIND WILL FIELD WILL BE LIGHTER WITH THE 0-6KM BULK SHEAR UNDER 25KTS. MID LEVEL LAPSE RATES STILL LOOK TO FALL BELOW 6.0 KM/C. OVERALL...CONVECTIVE PARAMETERS INDICATED A LOW CHANCE FOR ORGANIZED SEVERE THUNDERSTORMS. HOWEVER...LIKE YESTERDAY...ANY DISCREET CELL COULD BRIEFLY PULSE TO SEVERE LIMITS...FEATURING LARGE HAIL AND PERHAPS LOCALIZED WIND DAMAGE. AT THIS POINT...THE STORM PREDICTION CENTER HAS NOT PLACED ANY OF OUR REGION IN SLIGHT RISK. THE BIGGER CONCERN WITH THE STORMS WOULD BE EXCESSIVE RAINFALL. PWAT VALUES WHILE DOWN A LITTLE FROM LAST EVENING...WILL STILL RANGE BETWEEN 1.75-2.00 INCH...UP TO 3 STANDARDS ABOVE NORMAL. THE FREEZING LEVEL IS FORECAST TO DROP A LITTLE FROM 15,000 TO ABOUT 13,000 BY DAY/S END BUT STILL PLENTY HIGH FOR EFFICIENT RAIN FORMATION IN THE CLOUDS (WARM CLOUD PROCESSES). ALSO...MOST OF OUR AREA HAS EXCESSIVE MOIST SOILS DUE TO THE RASH OF HEAVY RAINFALL DURING THE PAST SIX WEEKS. CSTAR RESEARCH WOULD DICTATE NOT GOING WITH A GENERAL FLASH FLOOD WATCH DUE TO THE FACT THE THE AFOREMENTIONED UPPER AIR LOW PRESSURE BECOMES AN OPEN WAVE (AS OPPOSED TO A CUT-OFF). HOWEVER...AGAIN...DUE TO THE EXCESSIVE RAINFALL OUR REGION HAS EXPERIENCED WE FELT IT PRUDENT TO ISSUE ONE. WE HAVE PLACED OUR ENTIRE REGION IN A FLASH FLOOD WATCH FROM MIDDAY THROUGH THE EVENING HOURS. FLASH FLOOD GUIDANCE (FFG) VALUES ARE QUITE LOW...RANGING FROM 1-2 INCHES FOR HOURLY RAINFALL RATES ACROSS THE REGION. THE BOTTOM LINE...IT WOULD NOT TAKE A WHOLE LOT OF RAIN TO INDUCE POTENTIAL FLASH FLOODING TODAY...ESPECIALLY IN HERKIMER COUNTY...WHERE A PLETHORA OF FLASH FLOODS HAVE ALREADY ENSUED IN THE PAST WEEKS. IT WILL BE VERY HUMID ONCE MORE TODAY. THE CLOUDS AND MORE NUMEROUS SHOWERS/STORMS SHOULD KEEP HIGH TEMPERATURES A LITTLE LOWER THAN YESTERDAY...GENERALLY IN THE 80S...BUT AROUND 90 IN THE MID HUDSON VALLEY AND LOWER LITCHFIELD COUNTY. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE UPPER LEVEL LOW WILL STILL BE WORKING ACROSS OUR EASTERN REGIONS THROUGH THE EVENING HOURS WITH ON GOING SHOWERS AND THUNDERSTORMS. THESE SHOULD WANE LATER OVERNIGHT AND TOWARD DAYBREAK MOST OF THE REGION SHOULD BE PRECIPITATION FREE ONCE MORE...ALTHOUGH SOME SHOWERS MIGHT LINGER TO THE EAST OF THE HUDSON VALLEY. A TRAILING WEAK COLD FRONT LOOKS TO CROSS THE REGION THROUGH THE NIGHT. THE AIR BEHIND THIS FRONT WILL BE ONLY VERY SLIGHTLY COOLER IN THE MID LEVELS AND DRIER TOO. TUESDAY...WITH WEAK SUBSIDENCE AND THE SLIGHT DRYING...IT LOOKS AS IF THE SHOWER AND THUNDERSTORM COVERAGE WILL BE MUCH LOWER. STILL...THERE WILL STILL ENOUGH LOW LEVEL MOISTURE AROUND FOR INSTABILITY AND A RANDOM POP-UP THUNDERSTORM OR TWO DURING THE AFTERNOON..ESPECIALLY IN OUR SOUTHERN ZONES. WITH MORE SUNSHINE THAN MONDAY...RESULTANT HIGH TEMPERATURES WILL ACTUALLY BE A FEW POINTS HIGHER...ESPECIALLY IN THE VALLEYS WHERE 85-90 WILL COMMON WHILE THE HIGHER TERRAIN WILL RANGE FROM THE 80-85. A LIGHT WEST WIND WILL BECOME SOUTH BY LATE IN THE DAY. A SLIGHTLY STRONGER COLD FRONT IS POISED TO SLIP FROM THE GREAT LAKES AND HEAD TOWARD OUR REGION LATER TUESDAY NIGHT INTO WEDNESDAY. THIS FEATURE WILL TAKE ITS TIME APPROACHING AND ESPECIALLY CLEARING OUR REGION. IT LOOKS MAINLY DRY TUESDAY NIGHT (BUT DID KEEP 20 POPS FOR SHOWER OR THUNDERSTORM). BY WEDNESDAY...THE CHANCES WILL RAMP UP AGAIN AS THE FRONT NEAR AND THE ATMOSPHERE BECOMES MORE UNSTABLE. THE TIMING OF THE FRONT WILL HELP DETERMINE WHETHER OR NOT WE COULD BE LOOKING AT A POTENTIAL SEVERE WEATHER EVENT. RIGHT NOW...IT APPEARS THAT THE ACTUAL FRONT WILL NOT WORK ACROSS THE REGION UNTIL LATER WEDNESDAY NIGHT OR EARLY THURSDAY. WE WILL HAVE PLENTY OF TIME TO MONITOR THESE TRENDS. WEDNESDAY...AHEAD OF THE FRONT...TEMPERATURES WILL BE UNCOMFORTABLY WARM AND HUMID REACHING NEAR 90 IN THE MID HUDSON VALLEY...MID TO UPPER 80S MOST OTHER PLACES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MEDIUM RANGE MODELS (GFS/ECMWF) ARE NOW OFFERING SOME HOPE THAT MUCH OF THE LONG TERM PERIOD MAY BE RELATIVELY QUIET WEATHERIZE AND NOT AS HUMID. THE FORECAST FOR THE MAIN WEATHER FEATURES CALLS FOR THE COLD FRONT TO SHIFT SOUTH OF THE REGION EARLY ON THURSDAY... RESULTING IN MAINLY DRY WEATHER BY LATE IN THE DAY. THE UPPER LEVEL TROF THAT PUSHED THIS FRONT THROUGH IS THEN FORECAST TO CLOSE OFF/CUTOFF WELL TO THE SOUTHWEST OF THE REGION (OVER THE CENTRAL AND SOUTHERN APPALACHIANS) BY SATURDAY...AND THEN CONTINUE RETROGRADING WESTWARD DURING THE REST OF NEXT WEEKEND. AT THE SAME TIME THE RIDGE OVER THE WESTERN ATLANTIC WILL BUILD WESTWARD. THE RESULT OF ALL THIS IS THAT ONCE THE MOISTURE ASSOCIATED WITH FRONTAL BOUNDARY MOVES THROUGH...IT WILL HAVE A HARD TIME RETURNING NORTHWARD UNTIL THE RIDGE BUILDS WESTWARD AND THE SOUTHWEST FLOW AROUND IT BRINGS THE MOISTURE NORTHWARD AGAIN. HOWEVER...THIS IS NOT FORECAST TO HAPPEN UNTIL EARLY NEXT WEEK...SO THE PERIOD FROM THURSDAY NIGHT THROUGH SUNDAY IS GENERALLY FORECAST TO BE DRY BY BOTH THE GFS AND ECMWF. CONSIDERING THE WET PATTERN WE HAVE BEEN IN LATELY AND THAT THIS IS THE FIRST TIME BOTH MODELS SEEM TO INDICATE THE POSSIBILITY OF A DRY PERIOD...WILL NOT COMPLETELY REMOVE PCPN FROM THE FORECAST FOR NOW UNTIL LATER RUNS ALSO SUPPORT THIS DRIER PATTERN. AS THE FRONT SAGS SOUTH ON THURSDAY...HAVE FORECAST DECREASING POPS DURING THE DAY...THE DRY CONDITIONS THURSDAY NIGHT. ONLY A SLIGHT CHANCE FOR A SHOWER ON FRIDAY AND FRIDAY NIGHT...THEN A 30 PERCENT OF SHOWERS SATURDAY THROUGH SUNDAY WITH THUNDERSTORMS ALSO POSSIBLE SUNDAY AFTN/EVE. TEMPS WILL NOT BE AS WARM AS RECENTLY AND DEWPOINTS WILL ALSO BE 5 TO 10 DEGREES LOWER THAN RECENTLY. HIGHS THURSDAY WILL BE IN THE UPPER 70S TO MID 80S...MID 70S TO LOWER 80S FRIDAY...UPPER 70S TO MID 80S SATURDAY AND SUNDAY. LOWS THURSDAY AND FRIDAY NIGHTS WILL BE IN THE MID 50S TO MID 60S...AND UPPER 50S TO MID 60S SATURDAY NIGHT. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... AS AN UPPER LEVEL LOW TRACKS BY TO THE SOUTH OF THE REGION... EXPECT SCT TO NUMEROUS SHOWERS/TSTMS EXPECTED TO DEVELOP AGAIN THIS AFTERNOON...BUT AS WITH RECENT DAYS...TIMING AND LOCATION OF SHOWERS IS NOT POSSIBLE AT THIS TIME SO WILL ONLY FORECAST VCSH FOR NOW BETWEEN 08/16Z AND 09/01Z. WHERE SHOWERS/TSTMS DO OCCUR...WOULD EXPECT MVFR TO POSSIBLY IFR CIGS/VSBYS. OTHERWISE...HAVE FORECAST VFR CONDITIONS AT THE KALB/KGFL/KPOU/KPSF TAF SITES THROUGH LATE THIS EVENING. AFT AROUND 06Z TUESDAY...HAVE FORECAST SOME MVFR FOG AT KGFL AND KPSF. WINDS WILL BE CALM OR LIGHT AND VARIABLE THROUGH MID MORNING...THEN THEN BECOMING WEST-SOUTHWEST LATER ON TODAY AT SPEEDS OF 8 KTS OR LESS...THEN LIGHT AND VARIABLE AGAIN TONIGHT. OUTLOOK... TUE...MAINLY VFR. SCT -SHRA/-TSRA. WED...VFR/MVFR/IFR DUE TO SCT TO NUM -SHRA/-TSRA. THU-FRI...MAINLY VFR. SCT PM -SHRA/-TSRA. MVFR/IFR OVERNIGHT FOG POSSIBLE TUE-FRI. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SHOWERS AND THUNDERSTORMS WILL BECOME NUMEROUS ONCE MORE THIS AFTERNOON AND EARLY EVENING. THERE WILL BE LESS COVERAGE ON TUESDAY WITH MANY PLACES PERHAPS NOT RECEIVING ANY MEASURABLE RAINFALL. HOWEVER...MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED WEDNESDAY. NORMAL RH RECOVERIES EACH NIGHT BETWEEN 80 TO 100 PERCENT WILL ALLOW FOR WIDESPREAD DEW FORMATION. DAYTIME RH VALUES WILL GENERALLY BE IN THE 40 TO 60 PERCENT RANGE. && .HYDROLOGY... A FLASH FLOOD WATCH HAS BEEN ISSUED FOR OUR ENTIRE HSA FROM 1100 AM EDT THROUGH MIDNIGHT. THIS IS THE RESULT OF AN UPPER LEVEL LOW PRESSURE MOVING ACROSS THE REGION WITH VERY HIGH PWAT VALUES NEAR 2.00 INCHES. THE MOHAWK RIVER AT UTICA CONTINUES TO EXPERIENCE MINOR FLOODING. THE RIVER AND CREEK FLOWS NEAR THE WEST CENTRAL MOHAWK RIVER ARE EXPECTED TO GRADUALLY RECEDE INTO THE WEEKEND...UNLESS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OCCUR OVER OR NEAR THE BASIN. WHILE THE AVERAGE BASIN RAINFALL FORECAST INDICATED LESS THAN AN INCH OF RAIN TO FALL THROUGH THIS EVENING...THE COMBINATION OF MOIST SOILS...THE SLOW MOVING NATURE OF THE THUNDERSTORMS TODAY AND A VERY MOIST AIRMASS STILL IN PLACE WITH PWATS NEAR 2 INCHES...HAS PROMPTED THE FLOOD FLOOD WATCH. FLASH FLOOD GUIDANCE REMAINS UNUSUALLY LOW...IN THE 1-2 INCH RANGE. ANY THUNDERSTORM TODAY WOULD BE CAPABLE OF PRODUCING LOCALIZED RAINFALL AMOUNTS OF AN INCH OR BETTER IN HOUR OR LESS TIME AND THEREFORE THE NEED FOR THE WATCH. THUNDERSTORMS LOOK TO DIMINISH TONIGHT. TUESDAY...MUCH OF THE REGION COULD RECEIVE A BREAK IN THE ACTION...BUT A STRAY SHOWER OR THUNDERSTORM CANNOT BE ENTIRELY RULED...ESPECIALLY TO THE SOUTH OF ALBANY. PWATS LOOK TO DROP A LITTLE...DOWN TO AROUND 1.5 INCHES OR LITTLE LESS TO THE NORTH OF ALBANY. UNFORTUNATELY...A SLIGHTLY STRONGER COLD FRONT WILL APPROACH THE REGION WEDNESDAY REIGNITING THE THREAT OF SHOWERS AND THUNDERSTORMS INTO EARLY EARLY THURSDAY. WE MIGHT FINALLY CATCH A LITTLE MORE SUBSTANTIAL BREAK WITH POSSIBLE DRY WEATHER FRIDAY LASTING INTO THE BEGINNING OF THE WEEKEND. WHILE ADDITIONAL FLOODING IS NOT ANTICIPATED ON ANY MAIN STEM RIVER POINTS...LOCALLY SHARP RISES ARE POSSIBLE DUE TO ANY CONVECTION THAT MAY OCCUR OVER THE NEXT SEVERAL DAYS...ESPECIALLY FOR THOSE POINTS THAT ARE MORE FLASHIER IN NATURE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH THIS EVENING FOR CTZ001-013. NY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NYZ032-033-038>043- 047>054-058>061-063>066-082>084. MA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MAZ001-025. VT...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...HWJIV/WASULA NEAR TERM...HWJIV/WASULA SHORT TERM...HWJIV LONG TERM...GJM AVIATION...GJM FIRE WEATHER...HWJIV HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
659 AM EDT MON JUL 8 2013 .SYNOPSIS... A WEAK FRONTAL BOUNDARY MOVES THROUGH THE AREA LATE TODAY...WITH A COUPLE MORE AFFECTING THE AREA THROUGH MID WEEK. A SLOWLY MOVING COLD FRONT WILL PASS THROUGH THE REGION LATE THIS WEEKEND...AND MAY LINGER INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST MAINLY ON TRACK...WITH ONLY MINOR ADJUSTMENTS TO POPS BASED ON LATEST ENSEMBLE MESOSCALE OUTPUT. REMOVED SLIGHT CHANCE POPS FOR LIGHT RAIN MOVING UP FROM SE PA/DELMARVA THIS MORNING BASED ON LATEST HRRR AND LLJ MOVING EAST. OTHERWISE...A DISTINCT SHORTWAVE OVER WESTERN PA EARLY THIS MORNING SLOWLY SLIDING INTO THE REGION LATE THIS AFTERNOON/EVENING...WITH SURFACE/THERMAL TROUGHING CONTINUING ACROSS WESTERN ZONES. SUNSHINE WILL BE FILTERED BY SOME HIGH AND MID CLOUDS AHEAD OF THE SHORTWAVE...AND SCT CU DEVELOPMENT LIKELY ACROSS INTERIOR AND IN VICINITY OF SURFACE TROUGH AND SEABREEZE BOUNDARIES BY EARLY AFTERNOON. WITH BERMUDA RIDGING PUSHING TO THE EAST...WARMEST AIRMASS SHUNTED TO THE EAST AS WELL WITH TEMPS EXPECTED TO BE SEVERAL DEGREES COOLER TODAY. MODEL GUIDANCE AND UPSTREAM DEWPOINTS ARE POINTING TOWARDS DEWPOINTS RUNNING 3 TO 5 DEGREES LOWER TODAY THAN YESTERDAY AS WELL. HIGHS GENERALLY EXPECTED TO BE IN THE MID TO UPPER 80S ALONG THE COAST...AND UPPER 80S TO AROUND 90 INTERIOR AND NYC/NJ METRO. MAX HEAT INDICES ARE EXPECTED TO STAY CLOSE TO ACTUAL TEMPS ACROSS NYC/NJ METRO AND INTERIOR...GENERALLY LOWER 90S. SLIGHTLY STEEPENING MID LEVEL LAPSE RATES AND DAYTIME HEATING SHOULD RESULT IN MARGINAL TO MODERATE INSTABILITY LEVELS TO THE INTERIOR OF SEABREEZE BOUNDARIES. SHEAR LOOKS TO BE WEAK AS LLJ IS MAINLY EAST OF THE REGION. BASED ON ABOVE...EXPECTATION IS FOR ACTIVITY TO BE MORE PULSE IN NATURE. INITIALLY ACTIVITY SHOULD BE ISOLATED ACROSS HIGHER TERRAIN AND IN VICINITY OF SURFACE TROUGH AND SEABREEZE BOUNDARY EARLY THIS AFTERNOON. THEN AS SHORTWAVE ENERGY APPROACHES IN THE MID TO LATE AFTERNOON THE CONVECTIVE COVERAGE SHOULD INCREASE TO SCATTERED ACROSS THESE AREAS AND GRADUALLY PUSH EAST INTO THE EVENING. THIS IS GENERALLY CHARACTERIZED IN ENSEMBLE HIGH RES MODEL OUTPUT. ISOLATED PULSE STRONG TO SEVERE STORMS ARE POSSIBLE BASED ON INSTABILITY...WITH STRONG WINDS AND HEAVY RAINS THE HIGHER PROB HAZARDS. WITH PWATS FALLING CLOSER TO NORMAL AND MBE VECTORS SHOWING ENOUGH MOVEMENT TO STORMS...FLASH FLOODING LOOKS TO BE ISOLATED TO ANY TRAINING ALONG SEABREEZE/THERMAL TROUGHING. A MODERATE RISK OF RIP CURRENT CONTINUES FOR EASTERN LONG ISLAND ATLANTIC BEACHES TODAY. THERE IS POTENTIAL FOR SEABREEZE ACTIVITY TO INCREASE THE RIP CURRENT RISK TO MODERATE ACROSS THE REMAINDER OF THE ATLANTIC BEACHES LATE TODAY INTO THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... SHORTWAVE ENERGY/SURFACE TROUGH MOVE EAST TONIGHT WITH ANY CONVECTION EXPECTED TO DIMINISH. WEAK TROUGHING REMAIN OVER THE REGION ON TUESDAY...WITH A WARM FRONT TO THE SW OF THE REGION. MODELS INDICATING MCS DEVELOPING OVER THE GREAT LAKES THIS AFTERNOON INTO TONIGHT TRACKING SE ALONG THE WARM FRONT. BASED ON WARM FRONTAL POSITION AND SYNOPTIC FORCING REMAINING WELL S&W OF AREA...NOT EXPECTING TO BE AFFECTED DIRECTLY BY THIS ACTIVITY. COULD BE DEALING WITH CLOUD COVER FILTERING SUNSHINE THOUGH. CONVECTIVELY INDUCED VORTS AND MARGINAL TO MODERATE INSTABILITY COULD ALLOW FOR ISOLATED CONVECTION OFF THE HIGHER ELEVATIONS. OTHERWISE...WILL HAVE TO WATCH FOR ANY CONVECTION DEVELOPING OFF THE OUTFLOW FROM MCS ACTIVITY ACROSS PA...TRACKING INTO FAR W PORTIONS OF THE AREA LATE IN THE DAY. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... WEAK H5 TROUGH/SHORTWAVE COMBO SLIDES THROUGH THE REGION TUESDAY EVENING...AND ANY LINGERING SHOWERS/TSTMS WILL TAPER OFF IN THE EVENING. THEREAFTER...LOW PRES WILL TRACK FROM THE NORTHERN PLAINS STATES INTO THE UPPER GREAT LAKES...AND THEN INTO EASTERN CANADA. THIS WILL PUSH A WARM FRONT NORTH INTO THE REGION ON WEDNESDAY...AND THEN THE TRAILING COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION THURSDAY INTO FRIDAY. WITH INCREASING SOUTHERLY FLOW ON WEDNESDAY...VERY WARM AND HUMID CONDS ON TAP WITH TEMPS GENERALLY IN THE UPPER 80S TO LOWER 90S. WITH DEWPOINTS RISING INTO THE LOWER 70S...CAN EXPECT A HEAT INDEX GENERALLY IN THE LOW/MID 90S...AND IN THE MID/UPPER 90S ACROSS PARTS OF NYC AND NE NJ. TRAILING COLD FRONT WILL PUSH TOWARDS THE APPALACHIANS WEDNESDAY...AND SCT-NUM SHOWERS/TSTMS WILL DEVELOP AHEAD OF THE FRONT WITH THE BEST CHANCES OVER FAR NW ZONES. WILL INCREASE POPS TO LIKELY IN THOSE AREAS. UNSETTLED WEATHER CONTINUES THROUGH AT LEAST THURSDAY-FRIDAY AS COLD FRONT WORKS ITS WAY THROUGH THE REGION...BUT APPEARS TO GET HUNG UP JUST SOUTH AND EAST OF THE AREA. SOME MODEL DISCREPANCIES...AS THE GFS DEVELOPS A CLOSED LOW JUST OVER NYC ON FRIDAY...BUT THE ECMWF DOES NOT REALLY REFLECT THIS. UPPER TROUGH SLOWLY MOVES THROUGH THE REGION LATE FRIDAY/SATURDAY...AND DEPENDING ON HOW CLOSE THE FRONT HANGS TO THE COAST WILL DEPEND IF UNSETTLED WEATHER CONTINUES THROUGH THE WEEKEND. TEMPS WILL BE IN THE MID TO UPPER 80S THROUGH THURSDAY. BEHIND THE FRONT...TEMPS FALL BACK INTO THE LOW TO MID 80S FOR THE END OF THE WEEK AND OVER THE WEEKEND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... A WEAK SURFACE TROF WILL REMAIN NEAR THE TERMINALS THROUGH THE TAF PERIOD. MAINLY VFR. SOUTHWEST TO WEST-SOUTHWEST WINDS INCREASE TO 10-15KT AFTER THE MORNING PUSH. AFTERNOON GUSTS AT KEWR/KTEB/KLGA ARE EXPECTED ONCE AGAIN...UP TO AROUND 20KT. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ONCE AGAIN THIS AFTERNOON...HOWEVER IN TIMING AND PLACEMENT TOO LOW TO INCLUDE IN THE TAFS. BEST CHANCES WILL BE AFTER 20Z. BRIEF SUB-VFR CONDITIONS AND GUSTY WINDS CAN BE EXPECTED WITH ANY THUNDERSTORMS. WINDS DIMINISH TONIGHT TO LESS THAN 10 KT. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: WINDS COULD BECOME MORE SOUTHERLY THAN FORECAST. BEST CHANCE OF ANY CONVECTION WILL BE AFTER 20Z. KLGA FCSTER COMMENTS: TIMING OF GUSTS MAY START AN HOUR EARLIER THAN FORECAST. BEST CHANCE OF ANY CONVECTION WILL BE AFTER 20Z. KEWR FCSTER COMMENTS: TIMING OF GUSTS MAY START AN HOUR EARLIER THAN FORECAST. BEST CHANCE OF ANY CONVECTION WILL BE AFTER 20Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: TIMING OF GUSTS MAY START AN HOUR EARLIER THAN FORECAST. BEST CHANCE OF ANY CONVECTION WILL BE AFTER 20Z. KHPN FCSTER COMMENTS: BEST CHANCE OF ANY CONVECTION WILL BE AFTER 20Z. KISP FCSTER COMMENTS: WIND SPEEDS COULD BE A FEW KNOTS HIGHER THAN FORECAST. .OUTLOOK FOR 12Z MONDAY THROUGH FRI... .MON NIGHT-FRI...MAINLY VFR...BUT SUB-VFR POSSIBLE IN SCT TSTMS THRU THE ENTIRE PERIOD. && .MARINE... SUB SCA CONDS THROUGH TUESDAY WITH GENERAL SW WINDS EXPECTED. WINDS WILL INCREASE EACH AFT/EVE DUE TO ENHANCEMENT FROM SEA BREEZES. WINDS AND WAVES WILL REMAIN BELOW SCA CRITERIA TUESDAY THROUGH THURSDAY. A COLD FRONT WILL THEN APPROACH THE WATERS WITH A LOW LEVEL JET DEVELOPING. SEAS WILL BE ON THE INCREASE AND OCEAN SEAS COULD BE ABOVE 5 FT BUT THURSDAY MORNING AND REMAIN ELEVATED THROUGH FRIDAY. WINDS WILL ALSO BE AT MARGINAL SCA CRITERIA BEGINNING THURSDAY MORNING AND CONTINUING THROUGH FRIDAY. && .HYDROLOGY... SCATTERED SHOWERS/THUNDERSTORMS WILL PRODUCE LOCALLY HEAVY RAIN THIS AFTERNOON. FLASH FLOODING LOOKS TO BE ISOLATED TO ANY TRAINING ALONG SEABREEZE/THERMAL TROUGHING....WITH MINOR URBAN/POOR DRAINAGE/SMALL STREAM FLOODING THE MORE PROBABLE HAZARD. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE FOR THE MIDDLE TO THE END OF THE WEEK AS A COLD FRONT SLOWLY MOVES THROUGH THE REGION. ALTHOUGH THE PROBABILITY OF WIDESPREAD HEAVY RAIN IS LOW...LOCALLY HEAVY RAIN IS POSSIBLE IN ANY THUNDERSTORMS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MPS/NV NEAR TERM...NV SHORT TERM...NV LONG TERM...MPS AVIATION...BC MARINE...MPS/NV HYDROLOGY...MPS/NV
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1106 AM EDT Mon Jul 8 2013 .NEAR TERM [Through Tonight]... An upper level low moving northeast through New England has tilted a tropical moisture plume on SW/NE axis across our CWA. There is a subtle boundary currently draped across southeast Alabama and central Georgia that is expected to move SE during the day. This boundary, the afternoon sea breeze, and subsequent mesoscale boundaries will serve as sources for lift to initiate thunderstorms. Thus the PoP forecast for today reflects this forecast thinking. Higher PoPs will begin in the west and then shift east throughout the day. Our local WRF and the HRRR depict a similar pattern evolving throughout the afternoon. The concern today is with light flow in the 1000-700mb layer storm motion will be slow. Therefore where thunderstorms fire, they will be slow to move and could potentially dump lots of rain. For today expect partly cloudy skies with light winds and high temperatures reaching the lower 90s. && .SHORT TERM [Tuesday Through Wednesday]... Our forecast area will be situated in between two areas of high pressure, one over the western CONUS and one over the western Atlantic. Despite being in this weakness, the global models are not forecasting much synoptic scale forcing, which means that any forcing for rain will come from the sea breeze front and associated outflow boundary interactions during the afternoon and evening hours. The MOS PoP consensus is near to slightly below climatology, held in check by a band of dry air aloft, currently along the western flank of a Tropical Upper Tropospheric Low over the Bahamas that was translating westward. High temperatures will be warmer than the past several days...solidly in the mid 90s away from the beaches. However, heat index values will likely remain below 105 deg. && .LONG TERM [Wednesday Night through Sunday]... A rather unsettled pattern will continue across the region into next weekend with abundant low level moisture supporting typical summer-like thunderstorms in the afternoon and evening. Models drift weakening mid/upper low into the nern Gulf of Mexico by mid- week, and amplify large upper high over the srn/central Rockies. This should reestablish a well defined trough over the eastern 1/3 of the CONUS, with mid/upper low perhaps digging sswwd into the area next weekend. Overall, expect near seasonal temperatures. && .AVIATION [Beginning 14Z Monday]... Scattered showers and thunderstorms should develop once again across our area, possibly affecting all terminals after 17-18Z. A slightly drier airmass will be moving into our easternmost zones today so went with VCTS at VLD. Otherwise, convective TEMPO groups at all of the remaining TAF sites for this afternoon. && .MARINE... The coastal waters will be near a weakness in the subtropical Atlantic ridge, resulting in typically low summertime levels of winds and seas. && .FIRE WEATHER... No fire weather concerns. && .HYDROLOGY... The WPC 5-day QPF (through Friday afternoon) is only about an inch for our forecast area, which is about what we would expect for this time of year. Of course isolated amounts could be several times this amount, but they would likely be too spotty to significantly affect river stages, and would only be a flash flooding concern if they occurred in an urban area. Because most of the heavy rain last week fell across the lower portions of the river basins, most of the local forecast points that had significant river stage rises were already on their way down, including: the Choctawhatchee River at Geneva, AL (Action stage), Apalachicola River at Blountstown, FL (minor flood), Ochlockonee River at Thomasville, GA and Concord, FL, (both Action stage), the Withlacoochee River at Valdosta, GA (minor flood), St. Marks River near Newport, FL (minor flood), the Shoal River at Mossy Head (Action stage), Sopchoppy River at Sopchoppy, FL (moderate flood), and Aucilla River at Lamont, FL (minor flood). Some forecast points farther downstream were still on the rise, however, including: the Choctawhatchee River at Caryville (minor flood) and Bruce, FL (major flood), the Chipola River at Marianna, FL (Action stage), the Withlacoochee River at Pinetta, FL (Action stage), and the Econfina River near Perry, FL (Action stage). For the latest, detailed information on river stages near you, please visit our website at weather.gov, and follow the links to the "Advanced Hydrologic Prediction Center" (AHPS). && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 91 73 93 73 92 / 50 30 30 20 30 Panama City 89 75 89 75 88 / 40 20 30 20 30 Dothan 91 72 93 74 92 / 40 20 40 20 30 Albany 92 73 93 73 92 / 50 30 40 20 30 Valdosta 92 72 96 71 95 / 40 30 30 20 30 Cross City 92 72 93 71 91 / 40 20 30 20 40 Apalachicola 88 75 88 75 88 / 40 10 20 20 30 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Navarro/DVD SHORT TERM...Fournier LONG TERM...Evans AVIATION...Barry MARINE...Fournier FIRE WEATHER...Barry HYDROLOGY...Fournier
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
213 PM EDT MON JUL 8 2013 .PREV DISCUSSION... /ISSUED 752 AM EDT MON JUL 8 2013/ PREV DISCUSSION... /ISSUED 350 AM EDT MON JUL 8 2013/ SHORT TERM /TODAY THROUGH TUESDAY/... 500MB ANALYSIS SHOWS AN UPPER LOW MOVING INTO THE WESTERN MIDDLE ATLANTIC WITH A WEAK SHEAR AXIS EXTENDING INTO THE CENTRAL CWFA THIS MORNING. WV STILL DEPICTS THE HIGH MOISTURE PLUME VERY WELL ACROSS THE CENTRAL AND SOUTHERN CWFA...BUT ALSO SHOWS SOME DRIER AIR HAS WORKED ITS WAY INTO THE NORTHERN CWFA. THE TROUGH/SHEAR AXIS IS EXPECTED TO PUSH SOUTH TODAY. FORECAST PROBLEM OF THE DAY WILL BE POPS. SUSPECT THE CURRENT ACTIVITY ON THE REGIONAL RADAR LOOP HAS DEVELOP ALONG AND SOUTH OF THE SHEAR AXIS. DO THINK THE SHEAR AXIS WILL HELP SUPPORT CONVECTIVE DEVELOPMENT TODAY...ESPECIALLY ACROSS THE CENTRAL CWFA. THE LATEST RUN OF THE HRRR DOES SHOW SOME EARLY DEVELOPMENT ACROSS THE NORTHERN TIER OF ZONES THIS MORNING...AND THAT COULD BE ASSOCIATED WITH WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW. ALSO...ACROSS THE SOUTHERN CWFA...CONVECTIVE DEVELOPMENT COULD BE ENHANCED BY ANY ACTIVITY THAT DEVELOPS ALONG THE SEA BREEZE AND MOVES INLAND. THE BEST CHANCES FOR THUNDER SHOULD BE IN THE CENTRAL AND SOUTHERN ZONES...WHERE MORE BREAKS IN THE CLOUD COVER COULD OCCUR...SURFACE INSTABILITY WILL BE A LITTLE HIGHER AND THE SEA BREEZE COULD AID WITH LIFT. THE SHEAR AXIS SHOULD SET UP TO THE SOUTH TOMORROW...BUT BOTH THE GFS AND NAM ARE PROGGING ANOTHER PIECE OF SHORTWAVE ENERGY TO DROP SOUTH IN THE FLOW TOMORROW AFTERNOON. IN ADDITION...THE MOISTURE PLUME SHOULD BE LOCATED FURTHER SOUTH THAN TODAY. SO...EXPECT CONVECTION TO BE A LITTLE MORE DIURNAL IN NATURE. FOR NOW...LEFT GENERAL SCT POPS. WILL GO AHEAD AND LEAVE THE FLASH FLOOD WATCH IN EFFECT THROUGH TODAY. EVEN THOUGH THE COVERAGE OF POPS MAY BE LOWER THAN IN PREVIOUS DAYS ACROSS THE NORTH...ANY THUNDERSTORM COULD PRODUCE LOCALLY HEAVY RAINFALL. PWATS WILL DROP TO AROUND AN INCH AND A HALF IN THE NORTH...BUT A THUNDERSTORM COULD EASILY DROP A QUICK INCH OR MORE. FFG VALUES ARE AROUND AN INCH ACROSS MUCH OF THE AREA...WITH SOME AREAS LESS THAN A QUARTER OF AN INCH. NLISTEMAA LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE EXTENDED BEGINS WITH THE SOUTHEAST IN A GENERAL WEAKNESS PATTERN ALOFT...SANDWICHED BETWEEN THE TWO UPPER HIGHS /ONE IN THE ATLANTIC AND ONE IN THE SOUTHWEST STATES/ AND TWO UPPER LOWS OR TROUGHS /WEAK WAVE IN THE EASTERLIES OVER FLORIDA AND LONGWAVE TROUGH IN CANADA/. WEAK SURFACE BOUNDARY REMAINS IN PLACE TUESDAY NIGHT AND WEDNESDAY AND WHILE THERE IS VERY LITTLE FORCING... THERE WILL BE ENOUGH MOISTURE AND INSTABILITY TO KEEP SLIGHT TO LOW CHANCE POPS ACROSS THE AREA. WEDNESDAY NIGHT INTO THURSDAY...THE LONGWAVE TROUGH DEEPENS IN RESPONSE TO A SHORTWAVE RIDING DOWN THE NORTHWEST FLOW TOWARD THE OHIO VALLEY. THIS PUSHES A REINFORCING FRONT THROUGH THE TENNESSEE VALLEY AND INTO THE SOUTHEAST...WARRANTING HIGHER POPS FOR THURSDAY AFTERNOON. KEPT TREND OF LIKELY POPS UP NORTH. AS THE POSITIVELY TILTED TROUGH CONTINUES TO DEEPEN THE FRONT WILL PRETTY MUCH STALL ACROSS THE SOUTHEAST...THOUGH THERE IS SOME QUESTION AS TO HOW STRONG THE GREAT LAKES SURFACE HIGH WILL BE AND IF PORTIONS OF THE STATE ARE ABLE TO CLEAR OUT LATE IN THE WEEK...AS PER THE 00Z GFS...OR IF SIGNIFICANT MOISTURE REMAINS OVER THE ENTIRE AREA AS PER THE 00Z ECMWF. IF THE GFS IS TO BE BELIEVE...DRY AIR IS ABLE TO PUSH IN FRIDAY INTO SATURDAY LEADING TO OVERNIGHT LOWS IN THE 60S. ADD THIS TO TEMPS CONTINUING AT OR BELOW NORMAL...NOT BAD AT ALL FOR THIS TIME OF YEAR. BY SATURDAY MORNING THE GFS HAS ALREADY CUT OFF THE UPPER LOW ACROSS GEORGIA WHILE THE ECMWF JUST HAS A VERY LONG AND SKINNY TROUGH IN PLACE. THIS IS A PRETTY INTERESTING AND PERPLEXING CHANGE FROM LAST NIGHT/S SOLUTIONS...WHERE THE GFS AND ECMWF WERE IN REMARKABLE AGREEMENT WITH THE CUTOFF LOW. WITH TONIGHT/S RUNS... WHILE THE SENSIBLE WEATHER RESULTS ARE NOT ALL THAT DIFFERENT... THE MASS FIELDS ARE ACTUALLY QUITE A BIT DIFFERENT. IN EITHER CASE THOUGH...ABOVE-NORMAL PWATS REMAIN OVER THE SOUTHEAST. ADD TO THIS WHATEVER HAPPENS WITH CHANTAL...OR THE REMNANTS THEREOF. ENSEMBLE GUIDANCE TAKE THE SYSTEM SOMEWHERE INTO THE SOUTHEAST LATE IN THE PERIOD...GFS WITH A MORE NOTICEABLE CIRCULATION INTO THE JACKSONVILLE FLORIDA AREA...BUT THE ECMWF WITH JUST A GENERAL AREA OF MOISTURE INTO THE FLORIDA PENINSULA. SO ALL THAT SAID... HAVE KEPT POPS JUST ABOVE CLIMO FOR THE WEEKEND ESPECIALLY SUNDAY. TEMPS REMAIN AT OR BELOW NORMAL THROUGH THE WEEKEND. TDP && .AVIATION... 18Z UPDATE... SCT TO BKN CLOUDS OVER THE AREA AT THE MOMENT. CLOUD HEIGHTS ARE VFR AND SHOULD STAY THERE THROUGH 06Z. LOW STRATUS EXPECTED TO MOVE BACK IN ACROSS THE TAF SITES TONIGHT WITH IFR CEILINGS EXPECTED FROM 07Z TO 14 OR 15Z TUESDAY. THERE ARE SOME POP UP SHOWERS AND THUNDERSTORMS OUT THERE AND WE COULD SEE SOME AT THE ATL AREA TAF SITES THIS AFTERNOON. WILL SEE MVFR CEILINGS AND VSBYS IN AND AROUND ANY TSRA DEVELOPMENT. WINDS WILL STAY OUT OF THE W TO SW IN THE 5-10KT RANGE. //ATL CONFIDENCE...18Z UPDATE... CONFIDENCE MEDIUM TO HIGH ON ALL ELEMENTS. 01 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 84 71 88 71 / 40 30 40 30 ATLANTA 84 72 87 72 / 40 30 40 30 BLAIRSVILLE 81 64 82 66 / 40 30 40 30 CARTERSVILLE 85 70 87 71 / 40 30 40 30 COLUMBUS 86 73 91 73 / 40 30 40 20 GAINESVILLE 83 70 86 71 / 40 30 40 30 MACON 86 73 91 72 / 40 30 40 20 ROME 87 70 88 71 / 40 30 40 30 PEACHTREE CITY 84 70 88 71 / 40 30 40 30 VIDALIA 89 73 92 73 / 40 30 40 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING ZONES: BANKS...BARROW...BARTOW...CARROLL...CATOOSA...CHATTOOGA... CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...HENRY... JACKSON...LUMPKIN...MADISON...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PICKENS...POLK... ROCKDALE...SOUTH FULTON...TALIAFERRO...TOWNS...UNION...WALKER... WALTON...WHITE...WHITFIELD...WILKES. && $$ SHORT TERM...01 LONG TERM....41 AVIATION...01
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
752 AM EDT MON JUL 8 2013 .PREV DISCUSSION... /ISSUED 350 AM EDT MON JUL 8 2013/ SHORT TERM /TODAY THROUGH TUESDAY/... 500MB ANALYSIS SHOWS AN UPPER LOW MOVING INTO THE WESTERN MIDDLE ATLANTIC WITH A WEAK SHEAR AXIS EXTENDING INTO THE CENTRAL CWFA THIS MORNING. WV STILL DEPICTS THE HIGH MOISTURE PLUME VERY WELL ACROSS THE CENTRAL AND SOUTHERN CWFA...BUT ALSO SHOWS SOME DRIER AIR HAS WORKED ITS WAY INTO THE NORTHERN CWFA. THE TROUGH/SHEAR AXIS IS EXPECTED TO PUSH SOUTH TODAY. FORECAST PROBLEM OF THE DAY WILL BE POPS. SUSPECT THE CURRENT ACTIVITY ON THE REGIONAL RADAR LOOP HAS DEVELOP ALONG AND SOUTH OF THE SHEAR AXIS. DO THINK THE SHEAR AXIS WILL HELP SUPPORT CONVECTIVE DEVELOPMENT TODAY...ESPECIALLY ACROSS THE CENTRAL CWFA. THE LATEST RUN OF THE HRRR DOES SHOW SOME EARLY DEVELOPMENT ACROSS THE NORTHERN TIER OF ZONES THIS MORNING...AND THAT COULD BE ASSOCIATED WITH WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW. ALSO...ACROSS THE SOUTHERN CWFA...CONVECTIVE DEVELOPMENT COULD BE ENHANCED BY ANY ACTIVITY THAT DEVELOPS ALONG THE SEA BREEZE AND MOVES INLAND. THE BEST CHANCES FOR THUNDER SHOULD BE IN THE CENTRAL AND SOUTHERN ZONES...WHERE MORE BREAKS IN THE CLOUD COVER COULD OCCUR...SURFACE INSTABILITY WILL BE A LITTLE HIGHER AND THE SEA BREEZE COULD AID WITH LIFT. THE SHEAR AXIS SHOULD SET UP TO THE SOUTH TOMORROW...BUT BOTH THE GFS AND NAM ARE PROGGING ANOTHER PIECE OF SHORTWAVE ENERGY TO DROP SOUTH IN THE FLOW TOMORROW AFTERNOON. IN ADDITION...THE MOISTURE PLUME SHOULD BE LOCATED FURTHER SOUTH THAN TODAY. SO...EXPECT CONVECTION TO BE A LITTLE MORE DIURNAL IN NATURE. FOR NOW...LEFT GENERAL SCT POPS. WILL GO AHEAD AND LEAVE THE FLASH FLOOD WATCH IN EFFECT THROUGH TODAY. EVEN THOUGH THE COVERAGE OF POPS MAY BE LOWER THAN IN PREVIOUS DAYS ACROSS THE NORTH...ANY THUNDERSTORM COULD PRODUCE LOCALLY HEAVY RAINFALL. PWATS WILL DROP TO AROUND AN INCH AND A HALF IN THE NORTH...BUT A THUNDERSTORM COULD EASILY DROP A QUICK INCH OR MORE. FFG VALUES ARE AROUND AN INCH ACROSS MUCH OF THE AREA...WITH SOME AREAS LESS THAN A QUARTER OF AN INCH. NLISTEMAA LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE EXTENDED BEGINS WITH THE SOUTHEAST IN A GENERAL WEAKNESS PATTERN ALOFT...SANDWICHED BETWEEN THE TWO UPPER HIGHS /ONE IN THE ATLANTIC AND ONE IN THE SOUTHWEST STATES/ AND TWO UPPER LOWS OR TROUGHS /WEAK WAVE IN THE EASTERLIES OVER FLORIDA AND LONGWAVE TROUGH IN CANADA/. WEAK SURFACE BOUNDARY REMAINS IN PLACE TUESDAY NIGHT AND WEDNESDAY AND WHILE THERE IS VERY LITTLE FORCING... THERE WILL BE ENOUGH MOISTURE AND INSTABILITY TO KEEP SLIGHT TO LOW CHANCE POPS ACROSS THE AREA. WEDNESDAY NIGHT INTO THURSDAY...THE LONGWAVE TROUGH DEEPENS IN RESPONSE TO A SHORTWAVE RIDING DOWN THE NORTHWEST FLOW TOWARD THE OHIO VALLEY. THIS PUSHES A REINFORCING FRONT THROUGH THE TENNESSEE VALLEY AND INTO THE SOUTHEAST...WARRANTING HIGHER POPS FOR THURSDAY AFTERNOON. KEPT TREND OF LIKELY POPS UP NORTH. AS THE POSITIVELY TILTED TROUGH CONTINUES TO DEEPEN THE FRONT WILL PRETTY MUCH STALL ACROSS THE SOUTHEAST...THOUGH THERE IS SOME QUESTION AS TO HOW STRONG THE GREAT LAKES SURFACE HIGH WILL BE AND IF PORTIONS OF THE STATE ARE ABLE TO CLEAR OUT LATE IN THE WEEK...AS PER THE 00Z GFS...OR IF SIGNIFICANT MOISTURE REMAINS OVER THE ENTIRE AREA AS PER THE 00Z ECMWF. IF THE GFS IS TO BE BELIEVE...DRY AIR IS ABLE TO PUSH IN FRIDAY INTO SATURDAY LEADING TO OVERNIGHT LOWS IN THE 60S. ADD THIS TO TEMPS CONTINUING AT OR BELOW NORMAL...NOT BAD AT ALL FOR THIS TIME OF YEAR. BY SATURDAY MORNING THE GFS HAS ALREADY CUT OFF THE UPPER LOW ACROSS GEORGIA WHILE THE ECMWF JUST HAS A VERY LONG AND SKINNY TROUGH IN PLACE. THIS IS A PRETTY INTERESTING AND PERPLEXING CHANGE FROM LAST NIGHT/S SOLUTIONS...WHERE THE GFS AND ECMWF WERE IN REMARKABLE AGREEMENT WITH THE CUTOFF LOW. WITH TONIGHT/S RUNS... WHILE THE SENSIBLE WEATHER RESULTS ARE NOT ALL THAT DIFFERENT... THE MASS FIELDS ARE ACTUALLY QUITE A BIT DIFFERENT. IN EITHER CASE THOUGH...ABOVE-NORMAL PWATS REMAIN OVER THE SOUTHEAST. ADD TO THIS WHATEVER HAPPENS WITH CHANTAL...OR THE REMNANTS THEREOF. ENSEMBLE GUIDANCE TAKE THE SYSTEM SOMEWHERE INTO THE SOUTHEAST LATE IN THE PERIOD...GFS WITH A MORE NOTICEABLE CIRCULATION INTO THE JACKSONVILLE FLORIDA AREA...BUT THE ECMWF WITH JUST A GENERAL AREA OF MOISTURE INTO THE FLORIDA PENINSULA. SO ALL THAT SAID... HAVE KEPT POPS JUST ABOVE CLIMO FOR THE WEEKEND ESPECIALLY SUNDAY. TEMPS REMAIN AT OR BELOW NORMAL THROUGH THE WEEKEND. TDP && .AVIATION... 12Z UPDATE... LOW CIGS HAVE BEEN PROBLEMATIC THIS MORNING. CIGS HAVE BEEN BOUNCING BACK AND FORTH FROM VFR TO IFR/LIFR FOR THE LAST 4 HOURS AT SEVERAL TERMINAL SITES. LOW LIGHT VIS IMAGERY SHOWING A BANK OF LOW LEVEL STRATUS NEARING ATL...MIGHT HAVE TO AMD FOR THE LOW CIGS FOR A FEW HOURS THIS MORNING. DO THINK THEY WILL BURN OFF BY 14-15Z. SCT/BKN DIURNAL CU EXPECTED FOR THE AFTERNOON AROUND 040-050. LIGHT SW WINDS EXPECTED THROUGH THE DAY. //ATL CONFIDENCE...12Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 84 71 87 72 / 40 40 40 30 ATLANTA 84 72 86 73 / 40 40 40 30 BLAIRSVILLE 81 64 81 67 / 40 40 40 30 CARTERSVILLE 85 70 86 72 / 40 40 40 30 COLUMBUS 86 73 90 74 / 40 40 40 20 GAINESVILLE 83 70 85 72 / 40 40 40 30 MACON 86 73 90 73 / 40 40 40 20 ROME 87 70 87 72 / 40 40 40 30 PEACHTREE CITY 84 70 87 72 / 40 40 40 30 VIDALIA 89 74 91 74 / 40 40 40 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES: BANKS...BARROW...BARTOW...CARROLL...CATOOSA...CHATTOOGA... CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...HENRY... JACKSON...LUMPKIN...MADISON...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PICKENS...POLK... ROCKDALE...SOUTH FULTON...TALIAFERRO...TOWNS...UNION...WALKER... WALTON...WHITE...WHITFIELD...WILKES. && $$ SHORT TERM...ATWELL LONG TERM....ATWELL AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
350 AM EDT MON JUL 8 2013 .SHORT TERM /TODAY THROUGH TUESDAY/... 500MB ANALYSIS SHOWS AN UPPER LOW MOVING INTO THE WESTERN MIDDLE ATLANTIC WITH A WEAK SHEAR AXIS EXTENDING INTO THE CENTRAL CWFA THIS MORNING. WV STILL DEPICTS THE HIGH MOISTURE PLUME VERY WELL ACROSS THE CENTRAL AND SOUTHERN CWFA...BUT ALSO SHOWS SOME DRIER AIR HAS WORKED ITS WAY INTO THE NORTHERN CWFA. THE TROUGH/SHEAR AXIS IS EXPECTED TO PUSH SOUTH TODAY. FORECAST PROBLEM OF THE DAY WILL BE POPS. SUSPECT THE CURRENT ACTIVITY ON THE REGIONAL RADAR LOOP HAS DEVELOP ALONG AND SOUTH OF THE SHEAR AXIS. DO THINK THE SHEAR AXIS WILL HELP SUPPORT CONVECTIVE DEVELOPMENT TODAY...ESPECIALLY ACROSS THE CENTRAL CWFA. THE LATEST RUN OF THE HRRR DOES SHOW SOME EARLY DEVELOPMENT ACROSS THE NORTHERN TIER OF ZONES THIS MORNING...AND THAT COULD BE ASSOCIATED WITH WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW. ALSO...ACROSS THE SOUTHERN CWFA...CONVECTIVE DEVELOPMENT COULD BE ENHANCED BY ANY ACTIVITY THAT DEVELOPS ALONG THE SEA BREEZE AND MOVES INLAND. THE BEST CHANCES FOR THUNDER SHOULD BE IN THE CENTRAL AND SOUTHERN ZONES...WHERE MORE BREAKS IN THE CLOUD COVER COULD OCCUR...SURFACE INSTABILITY WILL BE A LITTLE HIGHER AND THE SEA BREEZE COULD AID WITH LIFT. THE SHEAR AXIS SHOULD SET UP TO THE SOUTH TOMORROW...BUT BOTH THE GFS AND NAM ARE PROGGING ANOTHER PIECE OF SHORTWAVE ENERGY TO DROP SOUTH IN THE FLOW TOMORROW AFTERNOON. IN ADDITION...THE MOISTURE PLUME SHOULD BE LOCATED FURTHER SOUTH THAN TODAY. SO...EXPECT CONVECTION TO BE A LITTLE MORE DIURNAL IN NATURE. FOR NOW...LEFT GENERAL SCT POPS. WILL GO AHEAD AND LEAVE THE FLASH FLOOD WATCH IN EFFECT THROUGH TODAY. EVEN THOUGH THE COVERAGE OF POPS MAY BE LOWER THAN IN PREVIOUS DAYS ACROSS THE NORTH...ANY THUNDERSTORM COULD PRODUCE LOCALLY HEAVY RAINFALL. PWATS WILL DROP TO AROUND AN INCH AND A HALF IN THE NORTH...BUT A THUNDERSTORM COULD EASILY DROP A QUICK INCH OR MORE. FFG VALUES ARE AROUND AN INCH ACROSS MUCH OF THE AREA...WITH SOME AREAS LESS THAN A QUARTER OF AN INCH. NLISTEMAA .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE EXTENDED BEGINS WITH THE SOUTHEAST IN A GENERAL WEAKNESS PATTERN ALOFT...SANDWICHED BETWEEN THE TWO UPPER HIGHS /ONE IN THE ATLANTIC AND ONE IN THE SOUTHWEST STATES/ AND TWO UPPER LOWS OR TROUGHS /WEAK WAVE IN THE EASTERLIES OVER FLORIDA AND LONGWAVE TROUGH IN CANADA/. WEAK SURFACE BOUNDARY REMAINS IN PLACE TUESDAY NIGHT AND WEDNESDAY AND WHILE THERE IS VERY LITTLE FORCING... THERE WILL BE ENOUGH MOISTURE AND INSTABILITY TO KEEP SLIGHT TO LOW CHANCE POPS ACROSS THE AREA. WEDNESDAY NIGHT INTO THURSDAY...THE LONGWAVE TROUGH DEEPENS IN RESPONSE TO A SHORTWAVE RIDING DOWN THE NORTHWEST FLOW TOWARD THE OHIO VALLEY. THIS PUSHES A REINFORCING FRONT THROUGH THE TENNESSEE VALLEY AND INTO THE SOUTHEAST...WARRANTING HIGHER POPS FOR THURSDAY AFTERNOON. KEPT TREND OF LIKELY POPS UP NORTH. AS THE POSITIVELY TILTED TROUGH CONTINUES TO DEEPEN THE FRONT WILL PRETTY MUCH STALL ACROSS THE SOUTHEAST...THOUGH THERE IS SOME QUESTION AS TO HOW STRONG THE GREAT LAKES SURFACE HIGH WILL BE AND IF PORTIONS OF THE STATE ARE ABLE TO CLEAR OUT LATE IN THE WEEK...AS PER THE 00Z GFS...OR IF SIGNIFICANT MOISTURE REMAINS OVER THE ENTIRE AREA AS PER THE 00Z ECMWF. IF THE GFS IS TO BE BELIEVE...DRY AIR IS ABLE TO PUSH IN FRIDAY INTO SATURDAY LEADING TO OVERNIGHT LOWS IN THE 60S. ADD THIS TO TEMPS CONTINUING AT OR BELOW NORMAL...NOT BAD AT ALL FOR THIS TIME OF YEAR. BY SATURDAY MORNING THE GFS HAS ALREADY CUT OFF THE UPPER LOW ACROSS GEORGIA WHILE THE ECMWF JUST HAS A VERY LONG AND SKINNY TROUGH IN PLACE. THIS IS A PRETTY INTERESTING AND PERPLEXING CHANGE FROM LAST NIGHT/S SOLUTIONS...WHERE THE GFS AND ECMWF WERE IN REMARKABLE AGREEMENT WITH THE CUTOFF LOW. WITH TONIGHT/S RUNS... WHILE THE SENSIBLE WEATHER RESULTS ARE NOT ALL THAT DIFFERENT... THE MASS FIELDS ARE ACTUALLY QUITE A BIT DIFFERENT. IN EITHER CASE THOUGH...ABOVE-NORMAL PWATS REMAIN OVER THE SOUTHEAST. ADD TO THIS WHATEVER HAPPENS WITH CHANTAL...OR THE REMNANTS THEREOF. ENSEMBLE GUIDANCE TAKE THE SYSTEM SOMEWHERE INTO THE SOUTHEAST LATE IN THE PERIOD...GFS WITH A MORE NOTICEABLE CIRCULATION INTO THE JACKSONVILLE FLORIDA AREA...BUT THE ECMWF WITH JUST A GENERAL AREA OF MOISTURE INTO THE FLORIDA PENINSULA. SO ALL THAT SAID... HAVE KEPT POPS JUST ABOVE CLIMO FOR THE WEEKEND ESPECIALLY SUNDAY. TEMPS REMAIN AT OR BELOW NORMAL THROUGH THE WEEKEND. TDP && .AVIATION... 06Z UPDATE... PERSISTENCE FORECAST ON TAP SINCE NO AIRMASS CHANGE. EXPECT IFR CIGS AT MOST TERMINAL SITES THIS MORNING...WITH SOME LIFR AT MCN AND CSG POSSIBLE. CIGS SHOULD START TO LIFT AROUND 12-14Z...BUT WILL REMAIN BKN VFR FOR THE AFTERNOON. WINDS WILL BE LIGHT TODAY AOB 10KT...BUT A SLIGHT SHIFT TO THE SW IS POSSIBLE THIS AFTERNOON. //ATL CONFIDENCE...06Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 84 71 87 72 / 60 40 40 30 ATLANTA 84 72 86 73 / 60 40 40 30 BLAIRSVILLE 81 64 81 67 / 60 40 40 30 CARTERSVILLE 85 70 86 72 / 50 40 40 30 COLUMBUS 86 73 90 74 / 60 40 40 20 GAINESVILLE 83 70 85 72 / 50 40 40 30 MACON 86 73 90 73 / 60 40 40 20 ROME 87 70 87 72 / 60 40 40 30 PEACHTREE CITY 84 70 87 72 / 60 40 40 30 VIDALIA 89 74 91 74 / 60 40 40 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES: BANKS...BARROW...BARTOW...CARROLL...CATOOSA...CHATTOOGA... CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...HENRY... JACKSON...LUMPKIN...MADISON...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PICKENS...POLK... ROCKDALE...SOUTH FULTON...TALIAFERRO...TOWNS...UNION...WALKER... WALTON...WHITE...WHITFIELD...WILKES. && $$ SHORT TERM...NLISTEMAA LONG TERM....TDP AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1006 PM CDT TUE JUL 9 2013 .DISCUSSION... 900 PM CDT NOT MUCH CHANGE TO PREVIOUS THINKING. VERY MOIST AND UNSTABLE AIRMASS STILL IN PLACE BUT WEAKLY CAPPED. WITH SHORT WAVE OVER THE IL/IN BORDER DEPARTING TO THE EAST THIS EVENING...LITTLE SUPPORT FOR ORGANIZED CONVECTION THIS EVENING. 0-6KM BULK SHEAR AROUND 30 KT SHOULD INCREASE SOME OVERNIGHT AS STRONG WAVE OVER MN CONTINUES TO DIG INTO THE GREAT LAKES. MAY STILL GET SOME SCATTERED CONVECTION WITH COLD FRONT LATER TONIGHT. A COUPLE CELLS SHOWING UP OVER NORTHEAST IA ATTM. HRRR AND OTHER SHORT RANGE GUIDANCE STILL SUGGESTING SOME SCATTERED ACTIVITY OVERNIGHT. BUT LOOKS LIKE MORE ORGANIZED STORMS OVER NE/KS WILL DRIVE E ACROSS MO INTO CENTRAL IL BY MORNING. WILL MAINTAIN LOW END POPS OVERNIGHT. ALLSOPP //PREV DISCUSSION... 250 PM CDT SHORT TERM...THIS EVENING THROUGH FRIDAY... SEVERE WEATHER/HEAVY RAINFALL POTENTIAL APPEARS TO BE DIMINISHING SIGNIFICANTLY ACROSS THE FORECAST AREA THROUGH TONIGHT. PERSISTENT ELEVATED CONVECTION AND ASSOCIATED CLOUD SHIELD HAS LIMITED STRONG DESTABILIZATION ACROSS MUCH OF THE CWA INTO THIS AFTERNOON. THIS...ALONG WITH A LACK OF STRONGER MID-LEVEL WINDS/DEEP SHEAR (WHICH WAS LAGGING SHORT WAVE FORCING ACROSS THE REGION) APPEARS TO HAVE DECREASED OUR POTENTIAL FOR STRONG/SEVERE THUNDERSTORMS ACROSS MUCH OF THE CWA THROUGH TONIGHT. AFTERNOON SURFACE ANALYSIS DEPICTS LOW PRESSURE OVER NORTHWEST WI WITH A WARM FRONTAL BOUNDARY EXTENDING SOUTHEAST TO SOUTHEAST WI/SOUTHERN LAKE MICHIGAN. A COLD FRONT TRAILED FROM THE LOW TO NORTHWESTERN IA AND CENTRAL KS. THE WARM SECTOR ACROSS CENTRAL IL WAS CHARACTERIZED BY TEMPS NEAR 90 AND DEW POINT TEMPS IN THE LOW-MID 70S...WHILE PERSISTENT CLOUDS/PRECIP HAVE HELD TEMPS INTO THE MID 70S-LOWER 80S ACROSS MUCH OF THE WFO LOT CWA. OUR COOLER BOUNDARY LAYER IS CLEARLY SHOWN IN AMDAR AIRCRAFT ASCENT SOUNDINGS FROM KMDW THIS AFTERNOON...AND SUPPORT SPC/RAP MESOANALYSIS DATA WHICH INDICATES A FAIRLY SUBSTANTIAL CAP IN PLACE ACROSS NORTHERN IL FOR SURFACE/NEAR SURFACE BASED PARCELS. AFTERNOON GOES SATELLITE WATER VAPOR IMAGERY INDICATES A SHORT-WAVE TROUGH APPROACHING THE MISSISSIPPI RIVER ACROSS MN/WI AND EASTERN IA AT THIS HOUR...WITH A VORT/MCV NOTED OVER SOUTHEAST IA. THIS SHOULD TRACK ACROSS THE WFO LOT CWA BETWEEN ROUGHLY 21-01Z AND MAY SERVE AS A TRIGGER FOR AN INCREASE IN CONVECTION ESPECIALLY SOUTH OF I-80...WHICH RAP/HRRR RUNS HAVE BEEN DEPICTING. APPROACH OF MODEST MID-LEVEL SPEED MAX AROUND 35 KT WOULD SUPPORT AN INCREASE IN EFFECTIVE BULK SHEAR VALUES TO 30-35 KT...WHICH MAY HELP ANY DEVELOPING CONVECTION BECOME BETTER ORGANIZED AND PERHAPS PRESENT A DAMAGING WIND THREAT ACROSS THE SOUTHERN CWA THROUGH THE LATE AFTERNOON. MID-LEVEL FEATURE LOOKS TO MOVE EAST OF THE CWA BY 01Z OR SO...WITH THUNDERSTORM THREAT SHIFTING LARGELY OFF TO THE EAST/SOUTH OF THE AREA BEYOND THAT TIME. ANY STORMS THAT DO DEVELOP WILL CONTINUE TO PRESENT A HEAVY RAINFALL THREAT...WITH PWATS RIGHT AROUND 2 INCHES. STRONGER SHORT WAVE TROUGH AND JET MAX FEATURE OVER THE NORTHERN PLAINS THIS AFTERNOON WILL PROPAGATE EAST-SOUTHEAST INTO THE WESTERN GREAT LAKES REGION BY WEDNESDAY MORNING...WITH MAIN AREA OF SURFACE LOW PRESSURE DEEPENING AND LIFTING ACROSS THE NORTHERN LAKES OVERNIGHT AND TRAILING THE AFOREMENTIONED COLD FRONT INTO NORTHERN IL LATE. WHILE SOME POTENTIAL FOR ADDITIONAL SHOWERS/THUNDERSTORMS CANT BE RULED OUT OVERNIGHT (POTENTIAL FOR DEVELOPMENT LATE THIS AFTERNOON MOST LIKELY OVER SOUTHEAST MN/WESTERN WI) UPSTREAM SOUNDINGS FROM ABR/OAX INDICATE SUBSTANTIAL DRY AIR ALOFT BEHIND LEAD SHORT WAVE OVER EASTERN IA...AND GUIDANCE HAS TRENDED MUCH DRIER AFTER INITIAL WAVE PASSES EARLY THIS EVENING. THUS HAVE ELECTED TO MAINTAIN SOME SLIGHT CHANCE POPS OVERNIGHT WITH ARRIVAL OF SURFACE FRONT AND LARGE SCALE FORCING FROM DIGGING NORTHERN PLAINS WAVE...THOUGH SUSPECT THAT THE POTENTIAL FOR STRONG THUNDERSTORMS AND ANY SEVERE/HEAVY RAIN THREAT WILL BE LIMITED TO THE LATE AFTERNOON AND EARLY EVENING HOURS. COLD FRONT THEN CONTINUES TO PUSH SOUTHEAST ACROSS THE FORECAST AREA WEDNESDAY MORNING...ENDING PRECIP THREAT FROM THE NORTHWEST. AFTER ANOTHER WARM/MUGGY NIGHT AHEAD OF THE FRONT TONIGHT...SOMEWHAT COOLER AND DRIER AIR WILL FILTER INTO THE AREA WEDNESDAY. NORTHERN COUNTIES WILL LIKELY SEE HIGHS IN THE UPPER 70S/LOW 80S WHILE THE SOUTH REMAINS A LITTLE MUGGIER IN THE MID/UPPER 80S. FULL EFFECTS OF THE CHANGE IN AIR MASS WILL BE FELT THURSDAY AND FRIDAY...WITH PLENTIFUL SUNSHINE AND UPPER 70S/LOW 80S CWA-WIDE...AND MID 70S ALONG THE LAKE WITH MODEST ONSHORE FLOW. RATZER EXTENDED...FRIDAY NIGHT THROUGH MONDAY... ALOFT THE LARGE HIGH OVER THE CENTRAL PLAINS STRENGTHENS AND GROWS IN SIZE ACROSS THE MID MISSISSIPPI RIVER VALLEY. AT THE SURFACE HIGH PRESSURE OVER THE EASTERN GREAT LAKES SHIFTS EAST OVER NEW ENGLAND. HOWEVER THE WESTERN EDGE OF THE HIGH REMAINS OVER THE REGION KEEPING THE ZONAL FLOW AND A SERIES OF SHORTWAVE TROUGHS AND WEAK LOWS TO OUR NORTH. THAT BEING SAID...IF THE HIGH SHIFTS SOUTH THE SYSTEMS COULD EASILY MOVE THROUGH NORTHERN IL AND NW INDIANA. AS IT STANDS NOW THE WEEKEND STARTS DRY WITH SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY NIGHT/MONDAY MAINLY ALONG THE IL/WI STATE LINE AS A SURFACE TROUGH PASSES THROUGH THE REGION. HIGH PRESSURE REESTABLISHES ITSELF ACROSS NORTHERN IL MONDAY NIGHT WITH DRY CONDITIONS EXPECTED FOR THE BEGINNING OF THE WORK WEEK. CONTINUED HOT AND MUGGY CONDITIONS ARE EXPECTED WITH TEMPS IN THE MID TO UPPER 80S AND DEWPOINTS IN THE 60S-70S THROUGHOUT THE EXTENDED. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * VERY LOW CHANCE OF A SHRA OR TSRA OR TWO OVERNIGHT. TRS //DISCUSSION...UPDATED 00Z... MODEL FORECAST AND AIRCRAFT REPORTED TEMPERATURE PROFILES SHOW A SMALL AREA OF CIN BETWEEN 1 AND 1.5KM AGL OVER THE AREA EARLY THIS EVE. THIS COMBINED WITH SUBSIDENCE IN WAKE OF THE AREA OF THUNDERSTORMS MOVING E ACROSS LOWER MI AND OH HAS KEPT EVEN CU DEVELOPMENT ACROSS THE LOCAL AREA ALMOST TOTALLY SUPPRESSED. WHILE THE UPPER TROUGH AND THE ASSOCIATED COLD FRONT HAVE YET TO MOVE ACROSS THE AREA IT WILL BE DOING SO DURING THE LATE OVERNIGHT AND PRE-DAWN HOURS. SURFACE CONVERGENCE WILL BE MINIMAL AT BEST ALONG THE COLD FRONT AND ONLY MODERATE MID TO UPPER LEVEL UVV SHOWN BY MODELS SO WHILE CANNOT TOTALLY RULE OUT ANY SHRA OR TSRA DURING THE NIGHT AND EARLY MORNING IT APPEARS TO BE A VERY SMALL THREAT AT THIS POINT. FOLLOWING THE COLD FRONTAL PASSAGE HIGH PRESSURE WILL BE BUILDING SE FROM THE NORTHERN PLAINS TO THE UPPER MIDWEST...WESTERN GREAT LAKES AND MID MS VALLEY DURING THE DAY WED. WNW WINDS TO BECOME NW TO NNW WITH TIME BUT GUSTS ONLY IN THE 15-20KT RANGE EXPECTED AS THE GRADIENT WEAKENS AS THE SURFACE RIDGE BUILDS INTO THE AREA. TRS //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH CONFIDENCE ALL FORECAST ELEMENTS. TRS //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THU THROUGH SUN...VFR. NO SIG WX. MON...VFR. SLGT CHANCE TSRA TRS && .MARINE... 250 PM CDT THE WEAK HIGH AND LOW ARE OVER SOUTHERN MI AND WILL CONTINUE TO DISSIPATE. A BROAD TROUGH OF LOW PRESSURE EXTENDS FROM NORTHERN ONTARIO THROUGH THE CENTRAL PLAINS AND IT WILL SLIDE OVER THE LAKE TONIGHT AND ITS COLD FRONT WILL ALSO SLIDE OVER THE LAKE LATE TONIGHT/EARLY WED MORNING. FOG HAS DISSIPATED OVER THE SOUTHERN HALF OF THE LAKE BUT IS HOLDING STRONG OVER THE NORTHERN HALF. THINKING THE FOG WILL DISSIPATE AS SHOWERS MOVE OVER THE NORTHERN HALF OF THE LAKE...BUT DENSE FOG MAY STICK AROUND OVER THE NORTH HALF OF THE LAKE UNTIL THE FRONT MOVES THROUGH EARLY WED MORNING. FOR NOW EXTENDED THE DENSE FOG ADVISORY THROUGH 9PM TONIGHT FOR AREAS NORTH OF A LINE CONNECTING SHEBOYGAN WI TO PENTWATER MI. WINDS TURN W TO NW BEHIND THE FRONT AND THEN WEAKEN/BECOME MORE VARIABLE LATE ON THURSDAY AS THE HIGH MOVES OVER THE LAKE. THE HIGH CONTINUES TO MOVE EAST OF THE LAKE ON FRIDAY WITH SE TO S WINDS EXPECTED ACROSS THE LAKE. WHILE THE HIGHS CENTER MOVES OVER NEW ENGLAND FRIDAY NIGHT/SATURDAY MORNING...S WINDS ARE EXPECTED THROUGH THE REST OF THE FORECAST PERIOD. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ868 UNTIL 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
911 PM CDT TUE JUL 9 2013 .DISCUSSION... 900 PM CDT NOT MUCH CHANGE TO PREVIOUS THINKING. VERY MOIST AND UNSTABLE AIRMASS STILL IN PLACE BUT WEAKLY CAPPED. WITH SHORT WAVE OVER THE IL/IN BORDER DEPARTING TO THE EAST THIS EVENING...LITTLE SUPPORT FOR ORGANIZED CONVECTION THIS EVENING. 0-6KM BULK SHEAR AROUND 30 KT SHOULD INCREASE SOME OVERNIGHT AS STRONG WAVE OVER MN CONTINUES TO DIG INTO THE GREAT LAKES. MAY STILL GET SOME SCATTERED CONVECTION WITH COLD FRONT LATER TONIGHT. A COUPLE CELLS SHOWING UP OVER NORTHEAST IA ATTM. HRRR AND OTHER SHORT RANGE GUIDANCE STILL SUGGESTING SOME SCATTERED ACTIVITY OVERNIGHT. BUT LOOKS LIKE MORE ORGANIZED STORMS OVER NE/KS WILL DRIVE E ACROSS MO INTO CENTRAL IL BY MORNING. WILL MAINTAIN LOW END POPS OVERNIGHT. ALLSOPP && .PREV DISCUSSION... 250 PM CDT SHORT TERM...THIS EVENING THROUGH FRIDAY... SEVERE WEATHER/HEAVY RAINFALL POTENTIAL APPEARS TO BE DIMINISHING SIGNIFICANTLY ACROSS THE FORECAST AREA THROUGH TONIGHT. PERSISTENT ELEVATED CONVECTION AND ASSOCIATED CLOUD SHIELD HAS LIMITED STRONG DESTABILIZATION ACROSS MUCH OF THE CWA INTO THIS AFTERNOON. THIS...ALONG WITH A LACK OF STRONGER MID-LEVEL WINDS/DEEP SHEAR (WHICH WAS LAGGING SHORT WAVE FORCING ACROSS THE REGION) APPEARS TO HAVE DECREASED OUR POTENTIAL FOR STRONG/SEVERE THUNDERSTORMS ACROSS MUCH OF THE CWA THROUGH TONIGHT. AFTERNOON SURFACE ANALYSIS DEPICTS LOW PRESSURE OVER NORTHWEST WI WITH A WARM FRONTAL BOUNDARY EXTENDING SOUTHEAST TO SOUTHEAST WI/SOUTHERN LAKE MICHIGAN. A COLD FRONT TRAILED FROM THE LOW TO NORTHWESTERN IA AND CENTRAL KS. THE WARM SECTOR ACROSS CENTRAL IL WAS CHARACTERIZED BY TEMPS NEAR 90 AND DEW POINT TEMPS IN THE LOW-MID 70S...WHILE PERSISTENT CLOUDS/PRECIP HAVE HELD TEMPS INTO THE MID 70S-LOWER 80S ACROSS MUCH OF THE WFO LOT CWA. OUR COOLER BOUNDARY LAYER IS CLEARLY SHOWN IN AMDAR AIRCRAFT ASCENT SOUNDINGS FROM KMDW THIS AFTERNOON...AND SUPPORT SPC/RAP MESOANALYSIS DATA WHICH INDICATES A FAIRLY SUBSTANTIAL CAP IN PLACE ACROSS NORTHERN IL FOR SURFACE/NEAR SURFACE BASED PARCELS. AFTERNOON GOES SATELLITE WATER VAPOR IMAGERY INDICATES A SHORT-WAVE TROUGH APPROACHING THE MISSISSIPPI RIVER ACROSS MN/WI AND EASTERN IA AT THIS HOUR...WITH A VORT/MCV NOTED OVER SOUTHEAST IA. THIS SHOULD TRACK ACROSS THE WFO LOT CWA BETWEEN ROUGHLY 21-01Z AND MAY SERVE AS A TRIGGER FOR AN INCREASE IN CONVECTION ESPECIALLY SOUTH OF I-80...WHICH RAP/HRRR RUNS HAVE BEEN DEPICTING. APPROACH OF MODEST MID-LEVEL SPEED MAX AROUND 35 KT WOULD SUPPORT AN INCREASE IN EFFECTIVE BULK SHEAR VALUES TO 30-35 KT...WHICH MAY HELP ANY DEVELOPING CONVECTION BECOME BETTER ORGANIZED AND PERHAPS PRESENT A DAMAGING WIND THREAT ACROSS THE SOUTHERN CWA THROUGH THE LATE AFTERNOON. MID-LEVEL FEATURE LOOKS TO MOVE EAST OF THE CWA BY 01Z OR SO...WITH THUNDERSTORM THREAT SHIFTING LARGELY OFF TO THE EAST/SOUTH OF THE AREA BEYOND THAT TIME. ANY STORMS THAT DO DEVELOP WILL CONTINUE TO PRESENT A HEAVY RAINFALL THREAT...WITH PWATS RIGHT AROUND 2 INCHES. STRONGER SHORT WAVE TROUGH AND JET MAX FEATURE OVER THE NORTHERN PLAINS THIS AFTERNOON WILL PROPAGATE EAST-SOUTHEAST INTO THE WESTERN GREAT LAKES REGION BY WEDNESDAY MORNING...WITH MAIN AREA OF SURFACE LOW PRESSURE DEEPENING AND LIFTING ACROSS THE NORTHERN LAKES OVERNIGHT AND TRAILING THE AFOREMENTIONED COLD FRONT INTO NORTHERN IL LATE. WHILE SOME POTENTIAL FOR ADDITIONAL SHOWERS/THUNDERSTORMS CANT BE RULED OUT OVERNIGHT (POTENTIAL FOR DEVELOPMENT LATE THIS AFTERNOON MOST LIKELY OVER SOUTHEAST MN/WESTERN WI) UPSTREAM SOUNDINGS FROM ABR/OAX INDICATE SUBSTANTIAL DRY AIR ALOFT BEHIND LEAD SHORT WAVE OVER EASTERN IA...AND GUIDANCE HAS TRENDED MUCH DRIER AFTER INITIAL WAVE PASSES EARLY THIS EVENING. THUS HAVE ELECTED TO MAINTAIN SOME SLIGHT CHANCE POPS OVERNIGHT WITH ARRIVAL OF SURFACE FRONT AND LARGE SCALE FORCING FROM DIGGING NORTHERN PLAINS WAVE...THOUGH SUSPECT THAT THE POTENTIAL FOR STRONG THUNDERSTORMS AND ANY SEVERE/HEAVY RAIN THREAT WILL BE LIMITED TO THE LATE AFTERNOON AND EARLY EVENING HOURS. COLD FRONT THEN CONTINUES TO PUSH SOUTHEAST ACROSS THE FORECAST AREA WEDNESDAY MORNING...ENDING PRECIP THREAT FROM THE NORTHWEST. AFTER ANOTHER WARM/MUGGY NIGHT AHEAD OF THE FRONT TONIGHT...SOMEWHAT COOLER AND DRIER AIR WILL FILTER INTO THE AREA WEDNESDAY. NORTHERN COUNTIES WILL LIKELY SEE HIGHS IN THE UPPER 70S/LOW 80S WHILE THE SOUTH REMAINS A LITTLE MUGGIER IN THE MID/UPPER 80S. FULL EFFECTS OF THE CHANGE IN AIR MASS WILL BE FELT THURSDAY AND FRIDAY...WITH PLENTIFUL SUNSHINE AND UPPER 70S/LOW 80S CWA-WIDE...AND MID 70S ALONG THE LAKE WITH MODEST ONSHORE FLOW. RATZER EXTENDED...FRIDAY NIGHT THROUGH MONDAY... ALOFT THE LARGE HIGH OVER THE CENTRAL PLAINS STRENGTHENS AND GROWS IN SIZE ACROSS THE MID MISSISSIPPI RIVER VALLEY. AT THE SURFACE HIGH PRESSURE OVER THE EASTERN GREAT LAKES SHIFTS EAST OVER NEW ENGLAND. HOWEVER THE WESTERN EDGE OF THE HIGH REMAINS OVER THE REGION KEEPING THE ZONAL FLOW AND A SERIES OF SHORTWAVE TROUGHS AND WEAK LOWS TO OUR NORTH. THAT BEING SAID...IF THE HIGH SHIFTS SOUTH THE SYSTEMS COULD EASILY MOVE THROUGH NORTHERN IL AND NW INDIANA. AS IT STANDS NOW THE WEEKEND STARTS DRY WITH SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY NIGHT/MONDAY MAINLY ALONG THE IL/WI STATE LINE AS A SURFACE TROUGH PASSES THROUGH THE REGION. HIGH PRESSURE REESTABLISHES ITSELF ACROSS NORTHERN IL MONDAY NIGHT WITH DRY CONDITIONS EXPECTED FOR THE BEGINNING OF THE WORK WEEK. CONTINUED HOT AND MUGGY CONDITIONS ARE EXPECTED WITH TEMPS IN THE MID TO UPPER 80S AND DEWPOINTS IN THE 60S-70S THROUGHOUT THE EXTENDED. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * OUTSIDE CHANCE OF A SHRA OR TSRA OR TWO LATE EVENING OR OVERNIGHT. TRS //DISCUSSION...UPDATED 00Z... MODEL FORECAST AND AIRCRAFT REPORTED TEMPERATURE PROFILES SHOW A SMALL AREA OF CIN BETWEEN 1 AND 1.5KM AGL OVER THE AREA EARLY THIS EVE. THIS COMBINED WITH SUBSIDENCE IN WAKE OF THE AREA OF THUNDERSTORMS MOVING E ACROSS LOWER MI AND OH HAS KEPT EVEN CU DEVELOPMENT ACROSS THE LOCAL AREA ALMOST TOTALLY SUPPRESSED. WHILE THE UPPER TROUGH AND THE ASSOCIATED COLD FRONT HAVE YET TO MOVE ACROSS THE AREA IT WILL BE DOING SO DURING THE LATE OVERNIGHT AND PRE-DAWN HOURS. SURFACE CONVERGENCE WILL BE MINIMAL AT BEST ALONG THE COLD FRONT AND ONLY MODERATE MID TO UPPER LEVEL UVV SHOWN BY MODELS SO WHILE CANNOT TOTALLY RULE OUT ANY SHRA OR TSRA DURING THE NIGHT AND EARLY MORNING IT APPEARS TO BE A VERY SMALL THREAT AT THIS POINT. FOLLOWING THE COLD FRONTAL PASSAGE HIGH PRESSURE WILL BE BUILDING SE FROM THE NORTHERN PLAINS TO THE UPPER MIDWEST...WESTERN GREAT LAKES AND MID MS VALLEY DURING THE DAY WED. WNW WINDS TO BECOME NW TO NNW WITH TIME BUT GUSTS ONLY IN THE 15-20KT RANGE EXPECTED AS THE GRADIENT WEAKENS AS THE SURFACE RIDGE BUILDS INTO THE AREA. TRS //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE ALL FORECAST ELEMENTS. TRS //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THU THROUGH SUN...VFR. NO SIG WX. MON...VFR. SLGT CHANCE TSRA TRS && .MARINE... 250 PM CDT THE WEAK HIGH AND LOW ARE OVER SOUTHERN MI AND WILL CONTINUE TO DISSIPATE. A BROAD TROUGH OF LOW PRESSURE EXTENDS FROM NORTHERN ONTARIO THROUGH THE CENTRAL PLAINS AND IT WILL SLIDE OVER THE LAKE TONIGHT AND ITS COLD FRONT WILL ALSO SLIDE OVER THE LAKE LATE TONIGHT/EARLY WED MORNING. FOG HAS DISSIPATED OVER THE SOUTHERN HALF OF THE LAKE BUT IS HOLDING STRONG OVER THE NORTHERN HALF. THINKING THE FOG WILL DISSIPATE AS SHOWERS MOVE OVER THE NORTHERN HALF OF THE LAKE...BUT DENSE FOG MAY STICK AROUND OVER THE NORTH HALF OF THE LAKE UNTIL THE FRONT MOVES THROUGH EARLY WED MORNING. FOR NOW EXTENDED THE DENSE FOG ADVISORY THROUGH 9PM TONIGHT FOR AREAS NORTH OF A LINE CONNECTING SHEBOYGAN WI TO PENTWATER MI. WINDS TURN W TO NW BEHIND THE FRONT AND THEN WEAKEN/BECOME MORE VARIABLE LATE ON THURSDAY AS THE HIGH MOVES OVER THE LAKE. THE HIGH CONTINUES TO MOVE EAST OF THE LAKE ON FRIDAY WITH SE TO S WINDS EXPECTED ACROSS THE LAKE. WHILE THE HIGHS CENTER MOVES OVER NEW ENGLAND FRIDAY NIGHT/SATURDAY MORNING...S WINDS ARE EXPECTED THROUGH THE REST OF THE FORECAST PERIOD. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ868 UNTIL 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
902 PM CDT TUE JUL 9 2013 .DISCUSSION... ISSUED 900 PM CDT TUE JUL 9 2013 TOUGH CALL ON TIMING OF ANY OVERNIGHT CONVECTION AS THE SHORT TERM MODELS HAVE BEEN HAVING QUITE A BIT OF DIFFICULTY TRACKING/PREDICTING STORM INITIATION/EVOLUTION TODAY SO FAR. SURFACE ANALYSIS SHOWS A COLD FRONT PROGRESSING ACROSS IOWA THIS EVENING. HOWEVER...THE NEAREST UPPER SUPPORT TO HELP WITH ANY UPDRAFTS THAT ARE TRIGGERED BY THE FRONT ARE WELL TO THE WEST IN NEBRASKA/KANSAS AND WESTERN MISSOURI...WHERE A SEVERE STORM WATCH IS IN EFFECT. WE EXPECT THE LOW LEVEL NOCTURNAL JET TO INCREASE AFTER SUNSET...AND AID IN STORM SUPPORT AS A COMPLEX TRIES TO GET ORGANIZED TOWARD MIDNIGHT ACROSS NORTHERN MISSOURI. THE LATEST IR SATELLITE PIX ARE SHOWING THAT CONVECTION IS FINALLY DEVELOPING IN NORTHWESTERN MISSOURI. THE 23Z HRRR OUTPUT PREDICTS ONE COMPLEX OF STORMS WILL RIDE NORTHEAST FROM IOWA INTO NORTHERN IL...AND ANOTHER COMPLEX IN MISSOURI WILL CURL TO THE SOUTHEAST CLIPPING SOUTHERN IL...WITH A WEAKER STORM COMPLEX BETWEEN THE TWO DRIFTING ACROSS CENTRAL IL ALONG THE COLD FRONT. WE HAVE PLENTY OF INSTABILITY AVAILABLE FOR STORMS ACROSS C IL...WITH 2000-3000 J/KG MLCAPE. SO STORMS SHOULD DEVELOP...BUT COVERAGE WILL BE MORE SCATTERED. VERY HEAVY RAINFALL WILL BE POSSIBLE. PWATS ARE AROUND 2.0 TO 2.2 INCHES. WE LOWERED POPS THIS EVENING TO SLIGHT CHANCE...AND LOWERED THE CHANCE POPS AFTER MIDNIGHT INTO THE 30-40 PCT RANGE INSTEAD OF AROUND 50 PCT. UPDATES WERE ALSO NEEDED TO SKY GRIDS. THE REMAINING GRIDS WERE GENERALLY ON TRACK. UPDATED FORECAST INFO WILL BE AVAILABLE SHORTLY. SHIMON && .AVIATION... ISSUED 654 PM CDT TUE JUL 9 2013 SHOWERS HAVE DEPARTED EAST OF CMI AND THE REST OF THE EVENING APPEARS TO BE DRY UNDER VFR CONDITIONS. A COLD FRONT/TROUGH IS STILL APPROACHING FROM IOWA...AND WILL BE A FOCUS FOR STRONGER STORMS TO DEVELOP LATER THIS EVENING AND ARRIVING IN WEST CENTRAL IL AFTER 05Z-06Z. LOW LEVEL JET DYNAMICS WILL COME INTO PLAY AS THE COMPLEX ERUPTS IN NORTHERN MISSOURI/SOUTHERN IOWA. SPC MESO- ANALYSIS SHOWS INCREASING SFC-BASED CIN, BUT ELEVATED STORMS ARE LIKELY TO CONTINUE TO PROPAGATE EASTWARD ACROSS ILLINOIS. DCAPE VALUES ARE QUITE LOW AT THIS POINT, BUT HIGH SURFACE DEWPOINTS SHOULD HELP KEEP THE THERMAL PROFILE FAVORABLE FOR SOME WIND GUSTS TO REACH THE GROUND AS THE COMPLEX BECOMES QUASI-LINEAR AFTER MIDNIGHT. WE WILL CONTINUE TO INDICATE A 3 HOUR WINDOW OF STORMS MOVING ACROSS THE TERMINAL SITES...STARTING IN THE WEST AT PIA/SPI AROUND 06Z-07Z...AND ADVANCING EASTWARD TO CMI BY 09Z-10Z. BRIEF PERIODS OF IFR AND LIFR WILL BE POSSIBLE IF ANY STORMS GO DIRECTLY OVER ANY TERMINAL SITE...BUT WE ONLY WENT DOWN TO MVFR CONDITIONS IN THE TAFS FOR NOW. WINDS WILL BEGIN SOUTHWEST UNTIL THE FRONT PASSES...THEN WINDS SHOULD SHIFT TO THE NORTHWEST BY WEDNESDAY MORNING. GUSTY NORTHWEST WINDS ARE EXPECTED BY WED AFTERNOON...UNDER VFR SKY AND VIS CONDITIONS. SHIMON && .PREV DISCUSSION... ISSUED 200 PM CDT TUE JUL 9 2013 BAND OF CONVECTION THAT FIRED EARLY THIS MORNING ACROSS IOWA HAS PUSHED EAST INTO NORTH CENTRAL IL JUST AHEAD OF A MID LEVEL SHORTWAVE. UPSTREAM FROM THAT WAVE IS A MORE SIGNIFICANT SHORTWAVE OVER NORTH DAKOTA THAT WILL BRING AN END TO THE HEAT AND HUMIDITY ALONG WITH THE THREAT FOR RAIN. AT THE SURFACE...THE 18Z ANALYSIS INDICATES A WEAK OUTFLOW BOUNDARY FROM THE MORNING CONVECTION LOCATED FROM JUST WEST OF LACON AND EAST OF PEORIA AND SPRINGFIELD. THERE WAS A MIX OF SUN AND CLOUDS EARLY THIS AFTERNOON WITH TEMPERATURES CURRENTLY RANGING FROM THE UPPER 80S TO LOWER 90S WITH HEAT INDEX VALUES AROUND 100. SHORT TERM...TONIGHT THROUGH FRIDAY SEVERE STORM THREAT TONIGHT THE MAIN FORECAST CHALLENGE. WILL FOLLOW THE HRRR AND THE NCEP HI-RES ARW MODELS AS THEY HAVE SHOW A BIT MORE CONSISTENCY WITH THE DEVELOPMENT OF CONVECTION LATER THIS AFTERNOON AND ESPECIALLY TONIGHT ALONG THE SOUTHEASTWARD MOVING COLD FRONT. WILL GRADUALLY PROGRESS THE HIGHEST POPS FROM NW TO SE OVERNIGHT AS THE COLD FRONT SETTLES INTO THE REGION. FORECAST SOUNDINGS STILL CONTINUE TO SHOW AN INCREASE IN MID LEVEL WINDS COINCIDENT WITH HIGH CAPE VALUES TONIGHT IN ADVANCE OF THE STRONGER UPPER LEVEL FORCING. AS A RESULT...A FEW OF THE STORMS WILL BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND TORRENTIAL RAINFALL WITH PRECIP WATER VALUES AROUND 2 INCHES. ASSUMING ORGANIZED CONVECTION DOES DEVELOP TO OUR NORTHWEST THIS EVENING...THE EFFECTIVE OUTFLOW BOUNDARY SHOULD BE PRESSING SE INTO THE I-70 CORRIDOR BY MORNING WITH THE ACTUAL SYNOPTIC COLD FRONT LAGGING BEHIND. POPS WILL LOWER FROM NW TO SE TOMORROW MORNING IN ANTICIPATION OF THE COLD FRONT SLIPPING SE OF I-70 BY 21Z. MAIN QUESTION IS WHETHER ANY STORMS CAN RE-FIRE AHEAD OF THE FRONT TOMORROW AFTN. IF WE SEE VERY LITTLE ACTIVITY TONIGHT...CHANCES ARE WE WILL SEE STORMS RE-FIRE AHEAD OF THE COLD FRONT ALONG THE I-70 CORRIDOR BEFORE SHIFTING OFF TO OUR SOUTHEAST BY EVENING. IF STORMS DO ORGANIZE...AND TRACK QUICKLY SE LATE TONIGHT...WE MAY NOT SEE ANY DEVELOPMENT ACRS THE SOUTHEAST TOMORROW AFTN. STILL SOME UNCERTAINTY WITH RESPECT TO FRONTAL POSITION ACRS SE IL SO WILL CONTINUE TO KEEP POPS GOING DOWN THERE THRU THE AFTN HOURS. PACIFIC HIGH PRESSURE WILL THEN BUILD EAST INTO THE MIDWEST BRINGING IN COOLER AND LESS HUMID AIR STARTING WEDNESDAY NIGHT AND CONTINUING THRU THE REST OF THE WORK WEEK. ONE MORE HOT AND HUMID DAY FOR THE SOUTHEAST WITH TEMPERATURES RISING INTO THE LOWER 90S WITH HEAT INDEX VALUES AT OR JUST ABOVE 100. AFTER THAT... WE SHOULD AFTERNOON TEMPS DROP BACK INTO THE LOW TO MID 80S AND SURFACE DEW POINTS BACK TO THE UPPER 50S TO LOWER 60S THURSDAY AND ESPECIALLY ON FRIDAY. LONG TERM...SATURDAY THROUGH TUESDAY UPPER LEVEL RIDGING STILL FORECAST TO BUILD OVER THE CENTER OF THE NATION DURING THIS PERIOD BRINGING RELATIVELY QUIET WEATHER TO OUR AREA. STRONGER MID LEVEL FLOW WILL SHIFT WELL TO OUR NORTH WITH TEMPERATURES RISING BACK INTO THE UPPER 80S TO AROUND 90 BY SUNDAY AND MONDAY. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
654 PM CDT TUE JUL 9 2013 .DISCUSSION... ISSUED 200 PM CDT TUE JUL 9 2013 BAND OF CONVECTION THAT FIRED EARLY THIS MORNING ACROSS IOWA HAS PUSHED EAST INTO NORTH CENTRAL IL JUST AHEAD OF A MID LEVEL SHORTWAVE. UPSTREAM FROM THAT WAVE IS A MORE SIGNIFICANT SHORTWAVE OVER NORTH DAKOTA THAT WILL BRING AN END TO THE HEAT AND HUMIDITY ALONG WITH THE THREAT FOR RAIN. AT THE SURFACE...THE 18Z ANALYSIS INDICATES A WEAK OUTFLOW BOUNDARY FROM THE MORNING CONVECTION LOCATED FROM JUST WEST OF LACON AND EAST OF PEORIA AND SPRINGFIELD. THERE WAS A MIX OF SUN AND CLOUDS EARLY THIS AFTERNOON WITH TEMPERATURES CURRENTLY RANGING FROM THE UPPER 80S TO LOWER 90S WITH HEAT INDEX VALUES AROUND 100. SHORT TERM...TONIGHT THROUGH FRIDAY SEVERE STORM THREAT TONIGHT THE MAIN FORECAST CHALLENGE. WILL FOLLOW THE HRRR AND THE NCEP HI-RES ARW MODELS AS THEY HAVE SHOW A BIT MORE CONSISTENCY WITH THE DEVELOPMENT OF CONVECTION LATER THIS AFTERNOON AND ESPECIALLY TONIGHT ALONG THE SOUTHEASTWARD MOVING COLD FRONT. WILL GRADUALLY PROGRESS THE HIGHEST POPS FROM NW TO SE OVERNIGHT AS THE COLD FRONT SETTLES INTO THE REGION. FORECAST SOUNDINGS STILL CONTINUE TO SHOW AN INCREASE IN MID LEVEL WINDS COINCIDENT WITH HIGH CAPE VALUES TONIGHT IN ADVANCE OF THE STRONGER UPPER LEVEL FORCING. AS A RESULT...A FEW OF THE STORMS WILL BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND TORRENTIAL RAINFALL WITH PRECIP WATER VALUES AROUND 2 INCHES. ASSUMING ORGANIZED CONVECTION DOES DEVELOP TO OUR NORTHWEST THIS EVENING...THE EFFECTIVE OUTFLOW BOUNDARY SHOULD BE PRESSING SE INTO THE I-70 CORRIDOR BY MORNING WITH THE ACTUAL SYNOPTIC COLD FRONT LAGGING BEHIND. POPS WILL LOWER FROM NW TO SE TOMORROW MORNING IN ANTICIPATION OF THE COLD FRONT SLIPPING SE OF I-70 BY 21Z. MAIN QUESTION IS WHETHER ANY STORMS CAN RE-FIRE AHEAD OF THE FRONT TOMORROW AFTN. IF WE SEE VERY LITTLE ACTIVITY TONIGHT...CHANCES ARE WE WILL SEE STORMS RE-FIRE AHEAD OF THE COLD FRONT ALONG THE I-70 CORRIDOR BEFORE SHIFTING OFF TO OUR SOUTHEAST BY EVENING. IF STORMS DO ORGANIZE...AND TRACK QUICKLY SE LATE TONIGHT...WE MAY NOT SEE ANY DEVELOPMENT ACRS THE SOUTHEAST TOMORROW AFTN. STILL SOME UNCERTAINTY WITH RESPECT TO FRONTAL POSITION ACRS SE IL SO WILL CONTINUE TO KEEP POPS GOING DOWN THERE THRU THE AFTN HOURS. PACIFIC HIGH PRESSURE WILL THEN BUILD EAST INTO THE MIDWEST BRINGING IN COOLER AND LESS HUMID AIR STARTING WEDNESDAY NIGHT AND CONTINUING THRU THE REST OF THE WORK WEEK. ONE MORE HOT AND HUMID DAY FOR THE SOUTHEAST WITH TEMPERATURES RISING INTO THE LOWER 90S WITH HEAT INDEX VALUES AT OR JUST ABOVE 100. AFTER THAT... WE SHOULD AFTERNOON TEMPS DROP BACK INTO THE LOW TO MID 80S AND SURFACE DEW POINTS BACK TO THE UPPER 50S TO LOWER 60S THURSDAY AND ESPECIALLY ON FRIDAY. LONG TERM...SATURDAY THROUGH TUESDAY UPPER LEVEL RIDGING STILL FORECAST TO BUILD OVER THE CENTER OF THE NATION DURING THIS PERIOD BRINGING RELATIVELY QUIET WEATHER TO OUR AREA. STRONGER MID LEVEL FLOW WILL SHIFT WELL TO OUR NORTH WITH TEMPERATURES RISING BACK INTO THE UPPER 80S TO AROUND 90 BY SUNDAY AND MONDAY. SMITH && .AVIATION... ISSUED 654 PM CDT TUE JUL 9 2013 SHOWERS HAVE DEPARTED EAST OF CMI AND THE REST OF THE EVENING APPEARS TO BE DRY UNDER VFR CONDITIONS. A COLD FRONT/TROUGH IS STILL APPROACHING FROM IOWA...AND WILL BE A FOCUS FOR STRONGER STORMS TO DEVELOP LATER THIS EVENING AND ARRIVING IN WEST CENTRAL IL AFTER 05Z-06Z. LOW LEVEL JET DYNAMICS WILL COME INTO PLAY AS THE COMPLEX ERUPTS IN NORTHERN MISSOURI/SOUTHERN IOWA. SPC MESO- ANALYSIS SHOWS INCREASING SFC-BASED CIN, BUT ELEVATED STORMS ARE LIKELY TO CONTINUE TO PROPAGATE EASTWARD ACROSS ILLINOIS. DCAPE VALUES ARE QUITE LOW AT THIS POINT, BUT HIGH SURFACE DEWPOINTS SHOULD HELP KEEP THE THERMAL PROFILE FAVORABLE FOR SOME WIND GUSTS TO REACH THE GROUND AS THE COMPLEX BECOMES QUASI-LINEAR AFTER MIDNIGHT. WE WILL CONTINUE TO INDICATE A 3 HOUR WINDOW OF STORMS MOVING ACROSS THE TERMINAL SITES...STARTING IN THE WEST AT PIA/SPI AROUND 06Z-07Z...AND ADVANCING EASTWARD TO CMI BY 09Z-10Z. BRIEF PERIODS OF IFR AND LIFR WILL BE POSSIBLE IF ANY STORMS GO DIRECTLY OVER ANY TERMINAL SITE...BUT WE ONLY WENT DOWN TO MVFR CONDITIONS IN THE TAFS FOR NOW. WINDS WILL BEGIN SOUTHWEST UNTIL THE FRONT PASSES...THEN WINDS SHOULD SHIFT TO THE NORTHWEST BY WEDNESDAY MORNING. GUSTY NORTHWEST WINDS ARE EXPECTED BY WED AFTERNOON...UNDER VFR SKY AND VIS CONDITIONS. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
256 PM CDT MON JUL 8 2013 .DISCUSSION... 1142 AM CDT FOR MORNING UPDATE... MCS CONTINUES TO MOVE SLOWLY TO THE EAST-SOUTHEAST ACROSS THE REGION LATE THIS MORNING...IN ASSOCIATION WITH A PAIR OF SHORT WAVE TROUGHS ANALYZED OVER LAKE MICHIGAN AND NORTHEAST IA/SOUTHWEST WI. MOST OF THE STRONGER CONVECTIVE ACTIVITY HAS BEEN OVER NORTHEAST IL OVER THE LAST COUPLE OF HOURS...ON NOSE OF 35-40 KT H8 WSWLY LOW LEVEL JET AND WITHIN PLUME OF SLIGHTLY STEEPER MID LEVEL LAPSE RATES PER SPC/RAP MESOANALYSIS. TRAINING CELLS HAVE PRODUCED SOME LOCALLY HEAVY RAINFALL AMOUNTS (1-3 INCHES FROM OBS/RADAR) ALONG A NARROW AXIS FROM JUST SOUTH OF ROCKFORD TO SYCAMORE/ELBURN AND THE SOUTH SIDE OF CHICAGO. CURRENT TRENDS INDICATE THIS AREA OF THUNDERSTORMS WILL CONTINUE TO TRACK OFF TO THE EAST-SOUTHEAST ACROSS NORTHWEST INDIANA INTO THE EARLY AFTERNOON HOURS...WITH DECREASING COVERAGE OF SHOWERS AND STORMS EXPECTED FROM THE WEST WITH SUBSIDENCE ASSOCIATED WITH PASSAGE OF MID-LEVEL SHORT WAVE TROUGH. WHILE LARGER SCALE FORCING SHOULD BECOME LESS FAVORABLE FOR ADDITIONAL DEVELOPMENT THIS AFTERNOON...EXPLICIT CONVECTION MODEL RUNS CONTINUE TO INDICATE SOME MORE SCATTERED REDEVELOPMENT OF CONVECTION ACROSS PARTS OF THE AREA THIS AFTERNOON. MORNING HRRR RUNS ARE ESPECIALLY BULLISH ON REDEVELOPING THUNDERSTORMS OVER NORTHEAST IL THIS AFTERNOON... THOUGH IT MAY NOT BE HANDLING LOW LEVEL WIND FIELD VERY WELL AND SUSPECT IT IS SOMEWHAT OVERDONE WITH ACTIVITY. VERY WARM/MOIST AND UNSTABLE ENVIRONMENT WILL BE PRESENT HOWEVER AS PARTIAL SUNSHINE DEVELOPS...WITH UPWARDS OF 2000 J/KG MLCAPE AVAILABLE PER WRF-NAM SOUNDINGS. HAVE LOWERED POPS TO SLIGHT CHANCE ACROSS MUCH OF NORTHERN IL AFTER CURRENT MCS EXITS THIS AFTERNOON...WITH SLIGHTLY HIGHER CHANCE POPS ACROSS THE SOUTH/SOUTHEAST WHERE PERSISTENT WARM ADVECTION AND OUTFLOW FROM MORNING STORMS MAY PROVIDE BETTER POTENTIAL FOR SOME REDEVELOPMENT. CLOUDS/RAIN HAVE HELD TEMPS IN THE 70S MOST AREAS THROUGH 11 AM. SUBSIDENCE WITH THE AFOREMENTIONED SHORT WAVE WAS ALLOWING SOME PARTIAL CLEARING FROM THE NORTHWEST AT MIDDAY HOWEVER. PROVIDED WE CAN GET A FEW HOURS OF PARTLY SUNNY SKIES...THERMAL RIDGE SHOULD EASILY PRODUCE HIGH TEMPS IN THE UPPER 80S ACROSS NORTHERN IL THIS AFTERNOON IF NOT A FEW LOWER 90S FAR WEST. EASTERN AREAS WILL BE A LITTLE TRICKIER BUT ALSO SHOULD BE CAPABLE OF SOME UPPER 80S WITH A LITTLE SUN. RATZER //PREV DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * CHANCE FOR ISOLD/SCATTERED TSRA LATE THIS AFTERNOON. * ANOTHER ROUND OF SHRA/TSRA POSSIBLE TUESDAY MORNING...WITH ADDITIONAL ACTIVITY LATER TUESDAY AFTERNOON/EVENING. MDB //DISCUSSION...UPDATED 20Z... CONTINUING TO MONITOR TSRA CHANCES THIS AFTERNOON AND HAVE A BIT BETTER CONFIDENCE IN THE POTENTIAL FOR ISOLD/SCATTERED ACTIVITY AFFECTING THE TERMINALS IN A FEW HOURS. SATELLITE AND RADAR SHOW THE DEVELOPMENT OF SPOTTY ACTIVITY ACROSS SOUTHEAST WI NORTH AND WEST OF MKE WHICH IS DRIFTING SOUTHEASTWARD. WITH THE UNSTABLE ATMOSPHERE IN PLACE AND SOME OF THE FORCING IN SE WI MOVING TOWARD THE AREA EXPECT THAT THIS ACTIVITY WILL MOVE INTO THE AREA IN A FEW HOURS SO WILL CONTINUE WITH VCTS MENTION. MDB FROM 18Z... BAND OF TSRA IS FINALLY EXITING THE CHI METRO AREA TO THE EAST. SSW WINDS ARE BECOMING SW WITH SOME GUSTS TO 18 OR 20 KT DEVELOPING AS CLOUD COVER DIMINISHES. MVFR CIGS NEAR GYY WILL IMPROVE IN THE NEXT HOUR OR TWO AS PRECIP EXITS. ATTENTION TURNS TO NEW SHRA/TSRA POTENTIAL LATER THIS AFTERNOON. A COOL FRONT MOVING SOUTHEAST ACROSS WISCONSIN MAY SERVE AS A TRIGGER FOR ADDITIONAL DEVELOPMENT AS IT REACHES THE AREA BUT THE UPPER WAVE RESPONSIBLE FOR THE MORNING STORMS LOOKS TO BE LEAVING A FAIR AMOUNT OF SINKING AIR IN ITS WAKE. THAT SAID...THE LOCAL AREA IS BECOMING UNSTABLE BEHIND THE CURRENT STORMS SO IT MAY NOT TAKE MUCH TO KICK OFF SOME ISOLATED ACTIVITY. HAD VCSH GOING IN THE PREVIOUS TAFS FOR THIS BUT WITH INSTABILITY GROWING TSRA WOULD LIKELY RESULT IF SOMETHING CAN DEVELOP SO CONVERTED TO VCTS. WITH CHANCE FOR DEVELOPMENT LOW...DEBATED REMOVING ANY MENTION ALTOGETHER BUT WANTED TO CONTINUE TO HIGHLIGHT THE CHANCE WHICH IS STILL IN THE 35-40 PERCENT RANGE. HAVE BETTER CONFIDENCE IN THE EVENING AND OVERNIGHT HOURS BEING DRY WITH DIMINISHING BUT VARIABLE WINDS. GIVEN THE RAINFALL AND THE LIGHT WINDS FOG WILL BE POSSIBLE AND HAVE INCLUDED PATCHY FOG /BCFG/ AT RFD/DPA/GYY...WITH AT LEAST SOME POTENTIAL FOR PERIODIC IFR CIGS LATE. SHRA/TSRA CHANCES CONTINUE TUESDAY. HAVE DECENT CONFIDENCE THAT THERE WILL BE A STORM COMPLEX DEVELOPING ACROSS NEBRASKA/IOWA TONIGHT WHICH WOULD THEN AFFECT THE LOCAL AREA SOME TIME TUESDAY MORNING. ADDITIONAL STORMS ARE POSSIBLE LATER TUESDAY BUT DEVELOPMENT MAY HINGE ON WHAT OCCURS EARLIER IN THE DAY. MDB //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM-CONFIDENCE IN ISOLD/SCATTERED IN THE AREA LATE THIS AFTERNOON. * MEDIUM CONFIDENCE IN SHRA/TSRA ACTIVITY TUESDAY MORNING...LOW CONFIDENCE IN COVERAGE AND TIMING...LOW CONFIDENCE IN SHRA/TSRA FORECAST TUESDAY AFTERNOON/EVENING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...LIKELY TSRA. MVFR/GUSTY WINDS POSSIBLE. WEDNESDAY...CHANCE OF TSRA...OTHERWISE VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. RODRIGUEZ && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
110 PM CDT MON JUL 8 2013 .DISCUSSION... 1142 AM CDT FOR MORNING UPDATE... MCS CONTINUES TO MOVE SLOWLY TO THE EAST-SOUTHEAST ACROSS THE REGION LATE THIS MORNING...IN ASSOCIATION WITH A PAIR OF SHORT WAVE TROUGHS ANALYZED OVER LAKE MICHIGAN AND NORTHEAST IA/SOUTHWEST WI. MOST OF THE STRONGER CONVECTIVE ACTIVITY HAS BEEN OVER NORTHEAST IL OVER THE LAST COUPLE OF HOURS...ON NOSE OF 35-40 KT H8 WSWLY LOW LEVEL JET AND WITHIN PLUME OF SLIGHTLY STEEPER MID LEVEL LAPSE RATES PER SPC/RAP MESOANALYSIS. TRAINING CELLS HAVE PRODUCED SOME LOCALLY HEAVY RAINFALL AMOUNTS (1-3 INCHES FROM OBS/RADAR) ALONG A NARROW AXIS FROM JUST SOUTH OF ROCKFORD TO SYCAMORE/ELBURN AND THE SOUTH SIDE OF CHICAGO. CURRENT TRENDS INDICATE THIS AREA OF THUNDERSTORMS WILL CONTINUE TO TRACK OFF TO THE EAST-SOUTHEAST ACROSS NORTHWEST INDIANA INTO THE EARLY AFTERNOON HOURS...WITH DECREASING COVERAGE OF SHOWERS AND STORMS EXPECTED FROM THE WEST WITH SUBSIDENCE ASSOCIATED WITH PASSAGE OF MID-LEVEL SHORT WAVE TROUGH. WHILE LARGER SCALE FORCING SHOULD BECOME LESS FAVORABLE FOR ADDITIONAL DEVELOPMENT THIS AFTERNOON...EXPLICIT CONVECTION MODEL RUNS CONTINUE TO INDICATE SOME MORE SCATTERED REDEVELOPMENT OF CONVECTION ACROSS PARTS OF THE AREA THIS AFTERNOON. MORNING HRRR RUNS ARE ESPECIALLY BULLISH ON REDEVELOPING THUNDERSTORMS OVER NORTHEAST IL THIS AFTERNOON... THOUGH IT MAY NOT BE HANDLING LOW LEVEL WIND FIELD VERY WELL AND SUSPECT IT IS SOMEWHAT OVERDONE WITH ACTIVITY. VERY WARM/MOIST AND UNSTABLE ENVIRONMENT WILL BE PRESENT HOWEVER AS PARTIAL SUNSHINE DEVELOPS...WITH UPWARDS OF 2000 J/KG MLCAPE AVAILABLE PER WRF-NAM SOUNDINGS. HAVE LOWERED POPS TO SLIGHT CHANCE ACROSS MUCH OF NORTHERN IL AFTER CURRENT MCS EXITS THIS AFTERNOON...WITH SLIGHTLY HIGHER CHANCE POPS ACROSS THE SOUTH/SOUTHEAST WHERE PERSISTENT WARM ADVECTION AND OUTFLOW FROM MORNING STORMS MAY PROVIDE BETTER POTENTIAL FOR SOME REDEVELOPMENT. CLOUDS/RAIN HAVE HELD TEMPS IN THE 70S MOST AREAS THROUGH 11 AM. SUBSIDENCE WITH THE AFOREMENTIONED SHORT WAVE WAS ALLOWING SOME PARTIAL CLEARING FROM THE NORTHWEST AT MIDDAY HOWEVER. PROVIDED WE CAN GET A FEW HOURS OF PARTLY SUNNY SKIES...THERMAL RIDGE SHOULD EASILY PRODUCE HIGH TEMPS IN THE UPPER 80S ACROSS NORTHERN IL THIS AFTERNOON IF NOT A FEW LOWER 90S FAR WEST. EASTERN AREAS WILL BE A LITTLE TRICKIER BUT ALSO SHOULD BE CAPABLE OF SOME UPPER 80S WITH A LITTLE SUN. RATZER //PREV DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * MORNING SHRA/TSRA EXITING BY ABOUT 19Z. * CHANCE FOR ADDITIONAL TSRA ACTIVITY LATE THIS AFTERNOON. * ANOTHER ROUND OF SHRA/TSRA POSSIBLE TUESDAY MORNING...WITH MORE ACTIVITY POSSIBLE LATER TUESDAY AFTERNOON/EVENING. MDB //DISCUSSION...UPDATED 18Z... BAND OF TSRA IS FINALLY EXITING THE CHI METRO AREA TO THE EAST. SSW WINDS ARE BECOMING SW WITH SOME GUSTS TO 18 OR 20 KT DEVELOPING AS CLOUD COVER DIMINISHES. MVFR CIGS NEAR GYY WILL IMPROVE IN THE NEXT HOUR OR TWO AS PRECIP EXITS. ATTENTION TURNS TO NEW SHRA/TSRA POTENTIAL LATER THIS AFTERNOON. A COOL FRONT MOVING SOUTHEAST ACROSS WISCONSIN MAY SERVE AS A TRIGGER FOR ADDITIONAL DEVELOPMENT AS IT REACHES THE AREA BUT THE UPPER WAVE RESPONSIBLE FOR THE MORNING STORMS LOOKS TO BE LEAVING A FAIR AMOUNT OF SINKING AIR IN ITS WAKE. THAT SAID...THE LOCAL AREA IS BECOMING UNSTABLE BEHIND THE CURRENT STORMS SO IT MAY NOT TAKE MUCH TO KICK OFF SOME ISOLATED ACTIVITY. HAD VCSH GOING IN THE PREVIOUS TAFS FOR THIS BUT WITH INSTABILITY GROWING TSRA WOULD LIKELY RESULT IF SOMETHING CAN DEVELOP SO CONVERTED TO VCTS. WITH CHANCE FOR DEVELOPMENT LOW...DEBATED REMOVING ANY MENTION ALTOGETHER BUT WANTED TO CONTINUE TO HIGHLIGHT THE CHANCE WHICH IS STILL IN THE 35-40 PERCENT RANGE. HAVE BETTER CONFIDENCE IN THE EVENING AND OVERNIGHT HOURS BEING DRY WITH DIMINISHING BUT VARIABLE WINDS. GIVEN THE RAINFALL AND THE LIGHT WINDS FOG WILL BE POSSIBLE AND HAVE INCLUDED PATCHY FOG /BCFG/ AT RFD/DPA/GYY...WITH AT LEAST SOME POTENTIAL FOR PERIODIC IFR CIGS LATE. SHRA/TSRA CHANCES CONTINUE TUESDAY. HAVE DECENT CONFIDENCE THAT THERE WILL BE A STORM COMPLEX DEVELOPING ACROSS NEBRASKA/IOWA TONIGHT WHICH WOULD THEN AFFECT THE LOCAL AREA SOME TIME TUESDAY MORNING. ADDITIONAL STORMS ARE POSSIBLE LATER TUESDAY BUT DEVELOPMENT MAY HINGE ON WHAT OCCURS EARLIER IN THE DAY. MDB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN CURRENT SHRA/TSRA EXITING BY ABOUT 19Z. * MEDIUM-HIGH CONFIDENCE THAT AFTERNOON TSRA CHANCE IS LOW. * MEDIUM CONFIDENCE IN SHRA/TSRA ACTIVITY TUESDAY MORNING...LOW CONFIDENCE IN COVERAGE AND TIMING...LOW CONFIDENCE IN SHRA/TSRA FORECAST TUESDAY AFTERNOON/EVENING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...LIKELY TSRA. MVFR/GUSTY WINDS POSSIBLE. WEDNESDAY...CHANCE OF TSRA...OTHERWISE VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. RODRIGUEZ && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1143 AM CDT MON JUL 8 2013 .DISCUSSION... 1142 AM CDT FOR MORNING UPDATE... MCS CONTINUES TO MOVE SLOWLY TO THE EAST-SOUTHEAST ACROSS THE REGION LATE THIS MORNING...IN ASSOCIATION WITH A PAIR OF SHORT WAVE TROUGHS ANALYZED OVER LAKE MICHIGAN AND NORTHEAST IA/SOUTHWEST WI. MOST OF THE STRONGER CONVECTIVE ACTIVITY HAS BEEN OVER NORTHEAST IL OVER THE LAST COUPLE OF HOURS...ON NOSE OF 35-40 KT H8 WSWLY LOW LEVEL JET AND WITHIN PLUME OF SLIGHTLY STEEPER MID LEVEL LAPSE RATES PER SPC/RAP MESOANALYSIS. TRAINING CELLS HAVE PRODUCED SOME LOCALLY HEAVY RAINFALL AMOUNTS (1-3 INCHES FROM OBS/RADAR) ALONG A NARROW AXIS FROM JUST SOUTH OF ROCKFORD TO SYCAMORE/ELBURN AND THE SOUTH SIDE OF CHICAGO. CURRENT TRENDS INDICATE THIS AREA OF THUNDERSTORMS WILL CONTINUE TO TRACK OFF TO THE EAST-SOUTHEAST ACROSS NORTHWEST INDIANA INTO THE EARLY AFTERNOON HOURS...WITH DECREASING COVERAGE OF SHOWERS AND STORMS EXPECTED FROM THE WEST WITH SUBSIDENCE ASSOCIATED WITH PASSAGE OF MID-LEVEL SHORT WAVE TROUGH. WHILE LARGER SCALE FORCING SHOULD BECOME LESS FAVORABLE FOR ADDITIONAL DEVELOPMENT THIS AFTERNOON...EXPLICIT CONVECTION MODEL RUNS CONTINUE TO INDICATE SOME MORE SCATTERED REDEVELOPMENT OF CONVECTION ACROSS PARTS OF THE AREA THIS AFTERNOON. MORNING HRRR RUNS ARE ESPECIALLY BULLISH ON REDEVELOPING THUNDERSTORMS OVER NORTHEAST IL THIS AFTERNOON... THOUGH IT MAY NOT BE HANDLING LOW LEVEL WIND FIELD VERY WELL AND SUSPECT IT IS SOMEWHAT OVERDONE WITH ACTIVITY. VERY WARM/MOIST AND UNSTABLE ENVIRONMENT WILL BE PRESENT HOWEVER AS PARTIAL SUNSHINE DEVELOPS...WITH UPWARDS OF 2000 J/KG MLCAPE AVAILABLE PER WRF-NAM SOUNDINGS. HAVE LOWERED POPS TO SLIGHT CHANCE ACROSS MUCH OF NORTHERN IL AFTER CURRENT MCS EXITS THIS AFTERNOON...WITH SLIGHTLY HIGHER CHANCE POPS ACROSS THE SOUTH/SOUTHEAST WHERE PERSISTENT WARM ADVECTION AND OUTFLOW FROM MORNING STORMS MAY PROVIDE BETTER POTENTIAL FOR SOME REDEVELOPMENT. CLOUDS/RAIN HAVE HELD TEMPS IN THE 70S MOST AREAS THROUGH 11 AM. SUBSIDENCE WITH THE AFOREMENTIONED SHORT WAVE WAS ALLOWING SOME PARTIAL CLEARING FROM THE NORTHWEST AT MIDDAY HOWEVER. PROVIDED WE CAN GET A FEW HOURS OF PARTLY SUNNY SKIES...THERMAL RIDGE SHOULD EASILY PRODUCE HIGH TEMPS IN THE UPPER 80S ACROSS NORTHERN IL THIS AFTERNOON IF NOT A FEW LOWER 90S FAR WEST. EASTERN AREAS WILL BE A LITTLE TRICKIER BUT ALSO SHOULD BE CAPABLE OF SOME UPPER 80S WITH A LITTLE SUN. RATZER && .PREV DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * RE-ORGANIZING LINE OF TSRA AFFECTING AREA TIL 18/19Z. PERIODIC IFR VSBY POSSIBLE...MAINLY AT MDW. * SOUTH-SOUTHWEST WINDS TURNING MORE SOUTHWEST EARLY THIS AFTERNOON. * LOW CHANCE FOR ADDITIONAL SHRA/TSRA LATER THIS AFTERNOON. * ANOTHER ROUND OF TSRA POSSIBLE EARLY TUESDAY MORNING. MDB //DISCUSSION...UPDATED 16Z... NARROW LINE OF TSRA HAS DEVELOPED FROM JUST NE OF DKB AND EXTENDS ACROSS MDW AND GYY. CELLS CONTINUE TO BUILD ON THE WESTERN TAIL OF THE LINE SUGGESTING THAT THE LINE WILL BE IN THE AREA FOR A FEW HOURS AS IT TRAINS EASTWARD. MDW/DPA/GYY LOOK TO REMAIN IN CLOSE PROXIMITY OR UNDERNEATH THE LINE WITH PERIODIC IFR VSBY AND HEAVY DOWNPOURS. ORD LOOKS TO REMAIN TO THE NORTH OF THE LINE BUT WITH THE NORTHWARD ARC BACK NEAR DKB AM CONCERNED THAT THEY MAY HAVE THE TAIL OF THE LINE CROSS THE TERMINAL IN ANOTHER HOUR OR TWO IF IT MAINTAINS ITSELF. WINDS HAVE BECOME STEADIER FROM THE SSW AND EXPECT A TRANSITION TO SW EARLY THIS AFTERNOON. LOW CHANCES FOR ADDITIONAL SHRA/TSRA CONTINUE THIS AFTERNOON. MDB FROM 12Z... SHOWERS WITH ISOLATED TS CURRENTLY PUSHING ACROSS TERMINALS THIS MORNING AS LARGE AREA OF PRECIP SPANNING MUCH OF THE REGION SHIFTS EAST. ALTHOUGH COVERAGE OF THIS PRECIP HAS HELD TOGETHER...THE OVERALL CONVECTIVE NATURE OF THIS SYSTEM HAS DIMINISHED OVER THE LAST ONE TO TWO HOURS WITH LIGHTNING BECOMING MORE LIMITED. NONETHELESS...HAVE OBSERVED A PERIODIC LIGHTNING STRIKE WITH THIS AREA OF PRECIP OVER THE LAST HOUR...AND SO HAVE MAINTAINED THE TEMPO GROUP FOR TS OVER THE NEXT COUPLE OF HOURS BEFORE THIS PRECIP CONTINUES TO SHIFT EAST OF THE TERMINALS. ALTHOUGH A BRIEF DRY PERIOD WILL BE OBSERVED WITH THE DEPARTURE OF THIS MORNINGS PRECIP...DO THINK THAT SCATTERED DEVELOPMENT WILL REMAIN POSSIBLE THIS AFTERNOON BUT WITH CONFIDENCE LOWER WITH REGARDS TO COVERAGE AS WELL AS INTENSITY. MOST OF THIS EVENING AND OVERNIGHT SHOULD REMAIN DRY...BUT WILL NEED TO CONTINUE MONITORING ANY DEVELOPMENT WEST OF THE REGION TONIGHT AS THIS PRECIP WILL BE CAPABLE OF SHIFTING EAST TOWARDS THE TERMINALS LATE TONIGHT EARLY TUESDAY MORNING AND COULD HAVE IMPACTS FOR THE TERMINALS. SOUTHWEST WEST WINDS WILL BE LIKELY TODAY WITH GUSTS INCREASING TO THE UPPER TEENS TODAY...BEFORE DIMINISHING THIS EVENING. THERE HAS BEEN A SLIGHT INCREASE IN GUSTS TO AROUND 20 KT MORE FROM A WESTERLY DIRECTION WITH THESE SHOWERS THIS MORNING. HAVE ADJUSTED THE TAFS TO REFLECT THIS POSSIBILITY AND TRENDS...BUT WITH THIS REMAINING BRIEF. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN TSRA CONTINUING WITH PERIODIC IFR VSBY...MEDIUM CONFIDENCE IN END TIME. * HIGH CONFIDENCE IN WIND DIRECTION TRENDS BUT MEDIUM CONFIDENCE IN TIMING OF CHANGES. * MEDIUM HIGH CONFIDENCE THAT POTENTIAL FOR ADDITIONAL SHRA/TSRA LATER THIS AFTERNOON IS LOW. * LOW CONFIDENCE IN SHRA/TSRA TIMING/COVERAGE TUESDAY MORNING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...LIKELY TSRA. MVFR/GUSTY WINDS POSSIBLE. WEDNESDAY...CHANCE OF TSRA...OTHERWISE VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. RODRIGUEZ && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1116 AM CDT MON JUL 8 2013 .DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * RE-ORGANIZING LINE OF TSRA AFFECTING AREA TIL 18/19Z. PERIODIC IFR VSBY POSSIBLE...MAINLY AT MDW. * SOUTH-SOUTHWEST WINDS TURNING MORE SOUTHWEST EARLY THIS AFTERNOON. * LOW CHANCE FOR ADDITIONAL SHRA/TSRA LATER THIS AFTERNOON. * ANOTHER ROUND OF TSRA POSSIBLE EARLY TUESDAY MORNING. MDB //DISCUSSION...UPDATED 16Z... NARROW LINE OF TSRA HAS DEVELOPED FROM JUST NE OF DKB AND EXTENDS ACROSS MDW AND GYY. CELLS CONTINUE TO BUILD ON THE WESTERN TAIL OF THE LINE SUGGESTING THAT THE LINE WILL BE IN THE AREA FOR A FEW HOURS AS IT TRAINS EASTWARD. MDW/DPA/GYY LOOK TO REMAIN IN CLOSE PROXIMITY OR UNDERNEATH THE LINE WITH PERIODIC IFR VSBY AND HEAVY DOWNPOURS. ORD LOOKS TO REMAIN TO THE NORTH OF THE LINE BUT WITH THE NORTHWARD ARC BACK NEAR DKB AM CONCERNED THAT THEY MAY HAVE THE TAIL OF THE LINE CROSS THE TERMINAL IN ANOTHER HOUR OR TWO IF IT MAINTAINS ITSELF. WINDS HAVE BECOME STEADIER FROM THE SSW AND EXPECT A TRANSITION TO SW EARLY THIS AFTERNOON. LOW CHANCES FOR ADDITIONAL SHRA/TSRA CONTINUE THIS AFTERNOON. MDB FROM 12Z... SHOWERS WITH ISOLATED TS CURRENTLY PUSHING ACROSS TERMINALS THIS MORNING AS LARGE AREA OF PRECIP SPANNING MUCH OF THE REGION SHIFTS EAST. ALTHOUGH COVERAGE OF THIS PRECIP HAS HELD TOGETHER...THE OVERALL CONVECTIVE NATURE OF THIS SYSTEM HAS DIMINISHED OVER THE LAST ONE TO TWO HOURS WITH LIGHTNING BECOMING MORE LIMITED. NONETHELESS...HAVE OBSERVED A PERIODIC LIGHTNING STRIKE WITH THIS AREA OF PRECIP OVER THE LAST HOUR...AND SO HAVE MAINTAINED THE TEMPO GROUP FOR TS OVER THE NEXT COUPLE OF HOURS BEFORE THIS PRECIP CONTINUES TO SHIFT EAST OF THE TERMINALS. ALTHOUGH A BRIEF DRY PERIOD WILL BE OBSERVED WITH THE DEPARTURE OF THIS MORNINGS PRECIP...DO THINK THAT SCATTERED DEVELOPMENT WILL REMAIN POSSIBLE THIS AFTERNOON BUT WITH CONFIDENCE LOWER WITH REGARDS TO COVERAGE AS WELL AS INTENSITY. MOST OF THIS EVENING AND OVERNIGHT SHOULD REMAIN DRY...BUT WILL NEED TO CONTINUE MONITORING ANY DEVELOPMENT WEST OF THE REGION TONIGHT AS THIS PRECIP WILL BE CAPABLE OF SHIFTING EAST TOWARDS THE TERMINALS LATE TONIGHT EARLY TUESDAY MORNING AND COULD HAVE IMPACTS FOR THE TERMINALS. SOUTHWEST WEST WINDS WILL BE LIKELY TODAY WITH GUSTS INCREASING TO THE UPPER TEENS TODAY...BEFORE DIMINISHING THIS EVENING. THERE HAS BEEN A SLIGHT INCREASE IN GUSTS TO AROUND 20 KT MORE FROM A WESTERLY DIRECTION WITH THESE SHOWERS THIS MORNING. HAVE ADJUSTED THE TAFS TO REFLECT THIS POSSIBILITY AND TRENDS...BUT WITH THIS REMAINING BRIEF. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN TSRA CONTINUING WITH PERIODIC IFR VSBY...MEDIUM CONFIDENCE IN END TIME. * HIGH CONFIDENCE IN WIND DIRECTION TRENDS BUT MEDIUM CONFIDENCE IN TIMING OF CHANGES. * MEDIUM HIGH CONFIDENCE THAT POTENTIAL FOR ADDITIONAL SHRA/TSRA LATER THIS AFTERNOON IS LOW. * LOW CONFIDENCE IN SHRA/TSRA TIMING/COVERAGE TUESDAY MORNING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...LIKELY TSRA. MVFR/GUSTY WINDS POSSIBLE. WEDNESDAY...CHANCE OF TSRA...OTHERWISE VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. RODRIGUEZ && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1047 AM CDT MON JUL 8 2013 .DISCUSSION... ISSUED 1045 AM CDT MON JUL 8 2013 FORECAST WAS ALREADY UPDATED EARLIER THIS MORNING AND WILL JUST NEED TO MAKE SLIGHT MODIFICATIONS OF THE CHANCES OF SHOWERS AND THUNDERSTORMS THE REST OF TODAY. WILL CONTINUE CHANCES (30-50%) OF SHOWERS AND THUNDERSTORMS OVER CENTRAL IL THIS AFTERNOON WITH JUST SLIGHT CHANCE (20%) OVER SOUTHEAST IL FROM I-70 SE. VERY WARM AND HUMID TODAY WITH HIGHS IN THE UPPER 80S AND LOWER 90S WITH DEWPOINTS IN THE LOWER 70S. AREA OF SHOWERS AND ISOLATED THUNDERSTORMS IS WEAKENING AS IT PRESSED SE INTO CENTRAL IL DURING THIS MORNING WITH LEADING EDGE OF LIGHTER SHOWERS AS FAR SOUTH AS I-72 WITH A FEW THUNDERSTORMS RECENTLY AROUND PEORIA. MODELS GENERALLY KEEP AREAS SE OF I-70 DRY THROUGH SUNSET WHILE TRYING TO DEVELOP MORE ISOLATED TO SCATTERED CONVECTION IN UNSTABLE AIRMASS THIS AFTERNOON OVER PARTS OF CENTRAL IL. SLIGHT RISK OF SEVERE STORMS IS OVER IA AND NORTHERN INDIANA AND COULD BE EXTENDED INTO NE IL BY CHICAGO. SPC HAS 5% RISK OF DAMAGING WIND GUSTS AND LARGE HAIL FROM I-72 NORTH SO CHANCES ARE VERY SMALL. 07 && .AVIATION... ISSUED 647 AM CDT MON JUL 8 2013 BAND OF SHOWERS AND ISOLATED STORMS MOVING THROUGH CENTRAL ILLINOIS EARLY THIS MORNING. CURRENTLY LOOKS LIKE MOST OF THE STORMS WILL PASS NORTH OF KPIA OVER THE NEXT HOUR OR TWO...BUT MORE EXPECTED TO DEVELOP LATER THIS MORNING. CONFIDENCE IN PLACEMENT OF ANY STORMS IS NOT VERY HIGH AT THE MOMENT...AS THERE IS POOR MODEL AGREEMENT IN ANY PARTICULAR TREND...SO HAVE GONE WITH MAINLY VCSH/VCTS MUCH OF THE DAY. THERE WILL PROBABLY BE A PERIOD OF DRIER CONDITIONS MUCH OF THE EVENING AND OVERNIGHT... HOWEVER A CONVECTIVE COMPLEX IS EXPECTED TO DEVELOP OVER MINNESOTA/IOWA TONIGHT...AND MAY AFFECT KPIA TOWARD SUNRISE. GEELHART && .PREV DISCUSSION... ISSUED 300 AM CDT MON JUL 8 2013 WARM AND HUMID CONDITIONS WITH PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PREVAIL FOR THE NEXT COUPLE OF DAYS...BEFORE COOLER AND DRIER WEATHER ARRIVES BY THE END OF THE WEEK. 07Z/2AM SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED OVER WESTERN WISCONSIN...WITH NEARLY STATIONARY BOUNDARY EXTENDING SOUTHWESTWARD INTO NEBRASKA. CONVECTION HAS DEVELOPED ALONG THIS BOUNDARY...AIDED BY A SUBTLE 500MB SHORT-WAVE OVER MINNESOTA AND A 30-35KT 850MB JET FROM THE SOUTHERN PLAINS INTO IOWA. SHORT TERM...TODAY THROUGH WEDNESDAY 00Z MODELS ARE PERFORMING VERY POORLY THUS FAR...WITH NONE OF THEM ADEQUATELY SHOWING THE CURRENT CONVECTION TO THE N/NW OF ILLINOIS. ONLY THE 05Z HRRR HAS A REASONABLE HANDLE ON THE SITUATION...SO WILL FOLLOW ITS SOLUTION CLOSELY FOR THE IMMEDIATE SHORT-TERM FORECAST. HRRR SHOWS A LINE OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN IOWA/FAR NORTHERN MISSOURI OVER THE NEXT COUPLE OF HOURS...THEN PUSHES THE LINE INTO THE NORTHERN KILX CWA AFTER 10Z. GIVEN 30KT LOW-LEVEL JET ORIENTED FROM KANSAS E/NE INTO WESTERN ILLINOIS THIS MORNING...THINK THIS IS A PLAUSIBLE SOLUTION. RADAR MOSAIC IS ALREADY SHOWING A BROKEN LINE OF CONVECTION DEVELOPING ALONG/WEST OF THE MISSISSIPPI RIVER...SO HAVE BUMPED POPS TO LIKELY ALONG AND NORTHWEST OF A RUSHVILLE TO BLOOMINGTON-NORMAL LINE THIS MORNING. AS LOW-LEVEL JET WEAKENS AND SHIFTS BACK WESTWARD...SHOWERS/THUNDER WILL TEND TO DISSIPATE LATER THIS MORNING AS IT SAGS SOUTHEASTWARD TOWARD THE I-72 CORRIDOR. WILL CARRY CHANCE POPS AS FAR SOUTH AS A SPRINGFIELD TO MATTOON LINE ACCORDINGLY...WITH ONLY SLIGHT CHANCES FOR ISOLATED THUNDER ACROSS THE FAR SE CWA THIS AFTERNOON. WILL BE A VERY WARM AND HUMID DAY...WITH HIGHS REACHING THE UPPER 80S AND LOWER 90S. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES TONIGHT...WITH TRAILING FRONTAL BOUNDARY SINKING SLIGHTLY FURTHER SOUTHWARD TO NEAR THE ILLINOIS/WISCONSIN BORDER. SCATTERED SHOWERS/THUNDER WILL PERSIST NEAR THE BOUNDARY...RESULTING IN LOW CHANCE POPS FOR THE NORTHERN TWO-THIRDS OF THE CWA TONIGHT. FURTHER SOUTH...LITTLE OR NO PRECIP IS ANTICIPATED ALONG/SOUTH OF I-70. AS LOW-LEVEL JET STRENGTHENS AND SHORT-WAVE CURRENTLY OVER UTAH TRACKS E/NE INTO THE NORTHERN PLAINS...AN MCS WILL LIKELY DEVELOP OVER SOUTHERN MINNESOTA/NORTHERN IOWA LATE TONIGHT. TRAJECTORIES TAKE THIS SYSTEM MAINLY EASTWARD ACROSS WISCONSIN AND NORTHERN ILLINOIS TUESDAY MORNING. THINK BULK OF THE CONVECTION WILL REMAIN JUST NORTH OF CENTRAL ILLINOIS...PRIMARILY ALONG/NORTH OF I-80. WILL FEATURE HIGHEST POPS ACROSS THE NORTHERN CWA ACCORDINGLY...WITH ONLY LOW CHANCE TO SLIGHT CHANCE POPS ACROSS THE CENTRAL AND SOUTHERN ZONES. MAIN STORY ON TUESDAY WILL BE THE HEAT AND HUMIDITY. AFTERNOON HIGH TEMPERATURES IN THE LOWER 90S COMBINED WITH DEWPOINTS IN THE LOWER TO MIDDLE 70S...WILL RESULT IN HEAT INDEX VALUES APPROACHING 100 DEGREES. BEST CHANCE FOR WIDESPREAD CONVECTION STILL ON TARGET FOR TUESDAY NIGHT INTO WEDNESDAY...AS NORTHERN STREAM WAVE CURRENTLY OVER THE PACIFIC NORTHWEST PUSHES COLD FRONT SOUTHWARD INTO CENTRAL ILLINOIS. WITH FRONT INTERACTING WITH A VERY MOIST AIR MASS CHARACTERIZED BY PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES...WILL CONTINUE TO FEATURE LIKELY POPS WITH FROPA. SEVERE WEATHER THREAT REMAINS UNCERTAIN...HOWEVER LOCALLY HEAVY RAINFALL WILL BE A GOOD BET WITH THE STORMS LATE TUESDAY NIGHT INTO WEDNESDAY. FRONT WILL DROP SOUTHWARD INTO THE OHIO RIVER VALLEY BY WEDNESDAY EVENING...ENDING THE THREAT FOR RAIN FROM NORTH TO SOUTH ACROSS THE AREA. WILL LINGER CHANCE POPS ALONG/SOUTH OF I-70 THROUGH WEDNESDAY EVENING...THEN WILL GO DRY ACROSS THE BOARD AFTER MIDNIGHT. LONG TERM...THURSDAY THROUGH SUNDAY COOLER/DRIER WEATHER WILL PREVAIL THROUGH THE EXTENDED...AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES. HIGH TEMPERATURES WILL ONLY REACH THE LOWER TO MIDDLE 80S...WHILE OVERNIGHT LOWS DROP INTO THE LOWER TO MIDDLE 60S. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
918 AM CDT MON JUL 8 2013 .DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * CLUSTERS OF TSRA NOW TIL AROUND 16Z WITH BRIEF IFR VSBY. * SOUTH-SOUTHWEST WINDS TURN TO WEST-SOUTHWEST SOMETIME EARLY THIS AFTERNOON. * LOW CHANCE FOR ADDITIONAL SHRA/TSRA THIS AFTERNOON. * ANOTHER ROUND OF SHRA/TSRA POSSIBLE EARLY TUESDAY MORNING. MDB //DISCUSSION...UPDATED 14Z... NEW BAND OF TSRA CLUSTERS CONTINUES TO MOVE EAST-SOUTHEAST INTO THE CHI METRO AREA AND WILL BE AFFECTING THE TERMINALS THROUGH 16/17Z AND PROBABLY SLIGHTLY LONGER AT GYY. RFD SHOULD BE CLEAR OF ACTIVITY BY 15Z AS UPPER WAVE RESPONSIBLE FOR THE ACTIVITY EXITS TO THE EAST. EXPECT THAT THERE WILL A LULL IN ACTIVITY EARLY/MID AFTERNOON BUT SOME LOW CHANCE WILL CONTINUE. LESS CONFIDENT LATER THIS AFTERNOON AS WE WILL BE UNSTABLE AND A FRONTAL BOUNDARY WILL BE SAGGING SOUTHWARD ACROSS SOUTHERN WI BUT ANY FOCUS FOR DEVELOPMENT OVER THE IMMEDIATE AREA LOOKS TO BE ABSENT. NEEDED TO REMOVE PROB30 FOR TSRA THIS AFTERNOON AS WE ENTERED THE FIRST 9 HOURS OF THE FORECAST WHERE IT CANNOT BE USED...BUT POTENTIAL FOR TSRA REMAINS AROUND 30 PERCENT. OTHER CONCERN IS WINDS...WINDS HAVE BECOME A BIT VARIABLE BETWEEN SOUTH AND SOUTHWEST AND NEAR TERM TRENDS SUPPORT A MORE SOUTHERLY DIRECTION WITH WEST-SOUTHWEST WINDS ARRIVING THIS AFTERNOON. ITS UNCLEAR HOW QUICKLY WINDS WILL SHIFT DUE TO THE ONGOING SHRA/TSRA. MDB FROM 12Z... SHOWERS WITH ISOLATED TS CURRENTLY PUSHING ACROSS TERMINALS THIS MORNING AS LARGE AREA OF PRECIP SPANNING MUCH OF THE REGION SHIFTS EAST. ALTHOUGH COVERAGE OF THIS PRECIP HAS HELD TOGETHER...THE OVERALL CONVECTIVE NATURE OF THIS SYSTEM HAS DIMINISHED OVER THE LAST ONE TO TWO HOURS WITH LIGHTNING BECOMING MORE LIMITED. NONETHELESS...HAVE OBSERVED A PERIODIC LIGHTNING STRIKE WITH THIS AREA OF PRECIP OVER THE LAST HOUR...AND SO HAVE MAINTAINED THE TEMPO GROUP FOR TS OVER THE NEXT COUPLE OF HOURS BEFORE THIS PRECIP CONTINUES TO SHIFT EAST OF THE TERMINALS. ALTHOUGH A BRIEF DRY PERIOD WILL BE OBSERVED WITH THE DEPARTURE OF THIS MORNINGS PRECIP...DO THINK THAT SCATTERED DEVELOPMENT WILL REMAIN POSSIBLE THIS AFTERNOON BUT WITH CONFIDENCE LOWER WITH REGARDS TO COVERAGE AS WELL AS INTENSITY. MOST OF THIS EVENING AND OVERNIGHT SHOULD REMAIN DRY...BUT WILL NEED TO CONTINUE MONITORING ANY DEVELOPMENT WEST OF THE REGION TONIGHT AS THIS PRECIP WILL BE CAPABLE OF SHIFTING EAST TOWARDS THE TERMINALS LATE TONIGHT EARLY TUESDAY MORNING AND COULD HAVE IMPACTS FOR THE TERMINALS. SOUTHWEST WEST WINDS WILL BE LIKELY TODAY WITH GUSTS INCREASING TO THE UPPER TEENS TODAY...BEFORE DIMINISHING THIS EVENING. THERE HAS BEEN A SLIGHT INCREASE IN GUSTS TO AROUND 20 KT MORE FROM A WESTERLY DIRECTION WITH THESE SHOWERS THIS MORNING. HAVE ADJUSTED THE TAFS TO REFLECT THIS POSSIBILITY AND TRENDS...BUT WITH THIS REMAINING BRIEF. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN TSRA CLUSTERS TIL AROUND 16Z...WITH BRIEF IFR VSBY. * MEDIUM CONFIDENCE IN SOUTH-SOUTHWEST WINDS TURNING WEST- SOUTHWEST...LOW-MEDIUM CONFIDENCE IN TIMING. * MEDIUM CONFIDENCE THAT POTENTIAL FOR ADDITIONAL SHRA/TSRA THIS AFTERNOON IS LOW. * LOW CONFIDENCE IN SHRA/TSRA TIMING/COVERAGE TUESDAY MORNING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...LIKELY TSRA. MVFR/GUSTY WINDS POSSIBLE. WEDNESDAY...CHANCE OF TSRA...OTHERWISE VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. RODRIGUEZ && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
705 AM CDT MON JUL 8 2013 .DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * SHOWERS WITH ISOLATED TS THROUGH 15Z...WITH POSSIBLE LOWER VIS. * CHANCES FOR SHOWERS AND POSSIBLE TS ONCE AGAIN LATER THIS AFTERNOON. * ANOTHER ROUND OF SHOWERS/THUNDERSTORMS POSSIBLE EARLY TUESDAY MORNING. RODRIGUEZ //DISCUSSION...UPDATED 12Z... SHOWERS WITH ISOLATED TS CURRENTLY PUSHING ACROSS TERMINALS THIS MORNING AS LARGE AREA OF PRECIP SPANNING MUCH OF THE REGION SHIFTS EAST. ALTHOUGH COVERAGE OF THIS PRECIP HAS HELD TOGETHER...THE OVERALL CONVECTIVE NATURE OF THIS SYSTEM HAS DIMINISHED OVER THE LAST ONE TO TWO HOURS WITH LIGHTNING BECOMING MORE LIMITED. NONETHELESS...HAVE OBSERVED A PERIODIC LIGHTNING STRIKE WITH THIS AREA OF PRECIP OVER THE LAST HOUR...AND SO HAVE MAINTAINED THE TEMPO GROUP FOR TS OVER THE NEXT COUPLE OF HOURS BEFORE THIS PRECIP CONTINUES TO SHIFT EAST OF THE TERMINALS. ALTHOUGH A BRIEF DRY PERIOD WILL BE OBSERVED WITH THE DEPARTURE OF THIS MORNINGS PRECIP...DO THINK THAT SCATTERED DEVELOPMENT WILL REMAIN POSSIBLE THIS AFTERNOON BUT WITH CONFIDENCE LOWER WITH REGARDS TO COVERAGE AS WELL AS INTENSITY. MOST OF THIS EVENING AND OVERNIGHT SHOULD REMAIN DRY...BUT WILL NEED TO CONTINUE MONITORING ANY DEVELOPMENT WEST OF THE REGION TONIGHT AS THIS PRECIP WILL BE CAPABLE OF SHIFTING EAST TOWARDS THE TERMINALS LATE TONIGHT EARLY TUESDAY MORNING AND COULD HAVE IMPACTS FOR THE TERMINALS. SOUTHWEST WEST WINDS WILL BE LIKELY TODAY WITH GUSTS INCREASING TO THE UPPER TEENS TODAY...BEFORE DIMINISHING THIS EVENING. THERE HAS BEEN A SLIGHT INCREASE IN GUSTS TO AROUND 20 KT MORE FROM A WESTERLY DIRECTION WITH THESE SHOWERS THIS MORNING. HAVE ADJUSTED THE TAFS TO REFLECT THIS POSSIBILITY AND TRENDS...BUT WITH THIS REMAINING BRIEF. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE WITH SHOWERS/TS TRENDS THIS MORNING. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS COVERAGE AND TIMING LATER THIS AFTERNOON. * LOW CONFIDENCE WITH SHOWERS/TS EARLY TUESDAY MORNING. * MEDIUM CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...LIKELY TSRA. MVFR/GUSTY WINDS POSSIBLE. WEDNESDAY...CHANCE OF TSRA...OTHERWISE VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. RODRIGUEZ && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
647 AM CDT MON JUL 8 2013 .DISCUSSION... ISSUED 300 AM CDT MON JUL 8 2013 WARM AND HUMID CONDITIONS WITH PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PREVAIL FOR THE NEXT COUPLE OF DAYS...BEFORE COOLER AND DRIER WEATHER ARRIVES BY THE END OF THE WEEK. 07Z/2AM SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED OVER WESTERN WISCONSIN...WITH NEARLY STATIONARY BOUNDARY EXTENDING SOUTHWESTWARD INTO NEBRASKA. CONVECTION HAS DEVELOPED ALONG THIS BOUNDARY...AIDED BY A SUBTLE 500MB SHORT-WAVE OVER MINNESOTA AND A 30-35KT 850MB JET FROM THE SOUTHERN PLAINS INTO IOWA. SHORT TERM...TODAY THROUGH WEDNESDAY 00Z MODELS ARE PERFORMING VERY POORLY THUS FAR...WITH NONE OF THEM ADEQUATELY SHOWING THE CURRENT CONVECTION TO THE N/NW OF ILLINOIS. ONLY THE 05Z HRRR HAS A REASONABLE HANDLE ON THE SITUATION...SO WILL FOLLOW ITS SOLUTION CLOSELY FOR THE IMMEDIATE SHORT-TERM FORECAST. HRRR SHOWS A LINE OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN IOWA/FAR NORTHERN MISSOURI OVER THE NEXT COUPLE OF HOURS...THEN PUSHES THE LINE INTO THE NORTHERN KILX CWA AFTER 10Z. GIVEN 30KT LOW-LEVEL JET ORIENTED FROM KANSAS E/NE INTO WESTERN ILLINOIS THIS MORNING...THINK THIS IS A PLAUSIBLE SOLUTION. RADAR MOSAIC IS ALREADY SHOWING A BROKEN LINE OF CONVECTION DEVELOPING ALONG/WEST OF THE MISSISSIPPI RIVER...SO HAVE BUMPED POPS TO LIKELY ALONG AND NORTHWEST OF A RUSHVILLE TO BLOOMINGTON-NORMAL LINE THIS MORNING. AS LOW-LEVEL JET WEAKENS AND SHIFTS BACK WESTWARD...SHOWERS/THUNDER WILL TEND TO DISSIPATE LATER THIS MORNING AS IT SAGS SOUTHEASTWARD TOWARD THE I-72 CORRIDOR. WILL CARRY CHANCE POPS AS FAR SOUTH AS A SPRINGFIELD TO MATTOON LINE ACCORDINGLY...WITH ONLY SLIGHT CHANCES FOR ISOLATED THUNDER ACROSS THE FAR SE CWA THIS AFTERNOON. WILL BE A VERY WARM AND HUMID DAY...WITH HIGHS REACHING THE UPPER 80S AND LOWER 90S. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES TONIGHT...WITH TRAILING FRONTAL BOUNDARY SINKING SLIGHTLY FURTHER SOUTHWARD TO NEAR THE ILLINOIS/WISCONSIN BORDER. SCATTERED SHOWERS/THUNDER WILL PERSIST NEAR THE BOUNDARY...RESULTING IN LOW CHANCE POPS FOR THE NORTHERN TWO-THIRDS OF THE CWA TONIGHT. FURTHER SOUTH...LITTLE OR NO PRECIP IS ANTICIPATED ALONG/SOUTH OF I-70. AS LOW-LEVEL JET STRENGTHENS AND SHORT-WAVE CURRENTLY OVER UTAH TRACKS E/NE INTO THE NORTHERN PLAINS...AN MCS WILL LIKELY DEVELOP OVER SOUTHERN MINNESOTA/NORTHERN IOWA LATE TONIGHT. TRAJECTORIES TAKE THIS SYSTEM MAINLY EASTWARD ACROSS WISCONSIN AND NORTHERN ILLINOIS TUESDAY MORNING. THINK BULK OF THE CONVECTION WILL REMAIN JUST NORTH OF CENTRAL ILLINOIS...PRIMARILY ALONG/NORTH OF I-80. WILL FEATURE HIGHEST POPS ACROSS THE NORTHERN CWA ACCORDINGLY...WITH ONLY LOW CHANCE TO SLIGHT CHANCE POPS ACROSS THE CENTRAL AND SOUTHERN ZONES. MAIN STORY ON TUESDAY WILL BE THE HEAT AND HUMIDITY. AFTERNOON HIGH TEMPERATURES IN THE LOWER 90S COMBINED WITH DEWPOINTS IN THE LOWER TO MIDDLE 70S...WILL RESULT IN HEAT INDEX VALUES APPROACHING 100 DEGREES. BEST CHANCE FOR WIDESPREAD CONVECTION STILL ON TARGET FOR TUESDAY NIGHT INTO WEDNESDAY...AS NORTHERN STREAM WAVE CURRENTLY OVER THE PACIFIC NORTHWEST PUSHES COLD FRONT SOUTHWARD INTO CENTRAL ILLINOIS. WITH FRONT INTERACTING WITH A VERY MOIST AIR MASS CHARACTERIZED BY PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES...WILL CONTINUE TO FEATURE LIKELY POPS WITH FROPA. SEVERE WEATHER THREAT REMAINS UNCERTAIN...HOWEVER LOCALLY HEAVY RAINFALL WILL BE A GOOD BET WITH THE STORMS LATE TUESDAY NIGHT INTO WEDNESDAY. FRONT WILL DROP SOUTHWARD INTO THE OHIO RIVER VALLEY BY WEDNESDAY EVENING...ENDING THE THREAT FOR RAIN FROM NORTH TO SOUTH ACROSS THE AREA. WILL LINGER CHANCE POPS ALONG/SOUTH OF I-70 THROUGH WEDNESDAY EVENING...THEN WILL GO DRY ACROSS THE BOARD AFTER MIDNIGHT. LONG TERM...THURSDAY THROUGH SUNDAY COOLER/DRIER WEATHER WILL PREVAIL THROUGH THE EXTENDED...AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES. HIGH TEMPERATURES WILL ONLY REACH THE LOWER TO MIDDLE 80S...WHILE OVERNIGHT LOWS DROP INTO THE LOWER TO MIDDLE 60S. BARNES && .AVIATION... ISSUED 647 AM CDT MON JUL 8 2013 BAND OF SHOWERS AND ISOLATED STORMS MOVING THROUGH CENTRAL ILLINOIS EARLY THIS MORNING. CURRENTLY LOOKS LIKE MOST OF THE STORMS WILL PASS NORTH OF KPIA OVER THE NEXT HOUR OR TWO...BUT MORE EXPECTED TO DEVELOP LATER THIS MORNING. CONFIDENCE IN PLACEMENT OF ANY STORMS IS NOT VERY HIGH AT THE MOMENT...AS THERE IS POOR MODEL AGREEMENT IN ANY PARTICULAR TREND...SO HAVE GONE WITH MAINLY VCSH/VCTS MUCH OF THE DAY. THERE WILL PROBABLY BE A PERIOD OF DRIER CONDITIONS MUCH OF THE EVENING AND OVERNIGHT... HOWEVER A CONVECTIVE COMPLEX IS EXPECTED TO DEVELOP OVER MINNESOTA/IOWA TONIGHT...AND MAY AFFECT KPIA TOWARD SUNRISE. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
439 AM CDT MON JUL 8 2013 .DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * WIDELY SCATTERED SHOWERS WITH ISOLATED TS EARLY THIS MORNING...WITH LIMITED OR NO VIS RESTRICTION EXPECTED. * SHOWERS AND TS ARRIVING LATER THIS MORNING AROUND 13-14Z...WITH MVFR VIS POSSIBLE. * CHANCES FOR SHOWERS AND POSSIBLE TS ONCE AGAIN LATER THIS AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... AS SEVERAL MID LEVEL DISTURBANCES APPROACH FROM THE WEST...LATEST RADAR IMAGERY SHOWING SCATTERED SHOWER DEVELOPMENT OCCURRING ACROSS NORTHWEST ILLINOIS EARLY THIS MORNING. EXPECT THIS SCATTERED DEVELOPMENT ALONG WITH ISOLATED TS TO PERSIST EARLY THIS MORNING...BUT WITH LITTLE IMPACTS TO THE TERMINALS EXPECTED. AM MONITORING SHOWER/TS DEVELOPMENT ACROSS NORTHERN/EASTERN IOWA AND EXPECT THIS AREA OF PRECIP TO SHIFT EASTWARD THROUGH THE EARLY MORNING HOURS AND MOVE ACROSS THE TERMINALS LATER THIS MORNING. WITH FAVORABLE METEOROLOGICAL CONDITIONS AND LATEST SHORT TERM GUIDANCE SHIFTING THIS PRECIP EAST THROUGH THE AREA...FELT COMFORTABLE ADDING IN A PREVAILING GROUP FOR AT LEAST SHOWERS FOR ALL OF THE TERMINALS THIS MORNING WHILE ALSO ADDING IN A TEMPO GROUP FOR POSSIBLE THUNDER THROUGH MID MORNING. SHOULD THEN OBSERVE THIS PRECIP EXIT TO THE EAST WITH A LULL IN THE ACTIVITY...BEFORE REDEVELOPMENT OCCURS WITH AN APPROACHING FRONT LATER THIS AFTERNOON. DO FEEL THAT SHOWERS/THUNDERSTORMS WILL DEVELOP AROUND THE AREA LATER THIS AFTERNOON...BUT CONFIDENCE IS LOWER WITH REGARDS TO TIMING/COVERAGE AND EVEN TS POTENTIAL. WILL CONTINUE TO MONITOR THIS AFTERNOON ACTIVITY AND ADJUST AS NEEDED. EXPECT SOUTHERLY WINDS THIS FORECAST PERIOD WITH A TREND MORE TOWARDS THE WEST SOUTHWEST THROUGH MID DAY...WHILE SPEEDS INCREASE AND SPORADIC GUSTS DEVELOP. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE WITH WIDELY SCATTERED SHOWERS/TS IN THE NEAR TERM. * HIGH CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS COVERAGE AND TIMING LATER THIS AFTERNOON. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY. MVFR/GUSTY WINDS POSSIBLE. * WEDNESDAY...CHANCE OF TSRA. * THURSDAY THROUGH SATURDAY...DRY/VFR. && .MARINE... 425 AM CDT AS AN AREA OF LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY SHIFTS EAST TOWARDS THE LAKE THIS MORNING...SOUTH TO SOUTHEAST WINDS OF 10 TO 20 KT ARE BEING OBSERVED ACROSS THE LAKE. WITH THIS LOW CONTINUING ACROSS THE LAKE TODAY...EXPECT FAIRLY DIFFERENT CONDITIONS FROM THE NORTH HALF TO THE SOUTH HALF. WITH THIS LOW MOVING THROUGH AND A BOUNDARY LEFT OVER THE LAKE...THE NORTHERN HALF OF THE LAKE WILL OBSERVE WINDS SHIFTING TO THE NORTHEAST AND EAST TODAY/TONIGHT WHILE THE SOUTHERN HALF REMAINS SOUTHWEST AND WEST. AN EASTERLY COMPONENT TO THE WIND LATE TONIGHT INTO TUESDAY WILL ONCE AGAIN TURN MORE SOUTHERLY AS NEW LOW PRESSURE DEVELOPS TO THE WEST. SPEEDS WILL INCREASE TO 10 TO 20 KT ON TUESDAY BEFORE TURNING TO THE SOUTHWEST AND WEST TUESDAY NIGHT...BEFORE A PERIOD OF NORTHERLY WINDS SETTLES IN ON WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
416 AM CDT MON JUL 8 2013 .DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * WIDELY SCATTERED SHOWERS WITH ISOLATED TS EARLY THIS MORNING...WITH LIMITED OR NO VIS RESTRICTION EXPECTED. * SHOWERS AND TS ARRIVING LATER THIS MORNING AROUND 13-14Z...WITH MVFR VIS POSSIBLE. * CHANCES FOR SHOWERS AND POSSIBLE TS ONCE AGAIN LATER THIS AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... AS SEVERAL MID LEVEL DISTURBANCES APPROACH FROM THE WEST...LATEST RADAR IMAGERY SHOWING SCATTERED SHOWER DEVELOPMENT OCCURRING ACROSS NORTHWEST ILLINOIS EARLY THIS MORNING. EXPECT THIS SCATTERED DEVELOPMENT ALONG WITH ISOLATED TS TO PERSIST EARLY THIS MORNING...BUT WITH LITTLE IMPACTS TO THE TERMINALS EXPECTED. AM MONITORING SHOWER/TS DEVELOPMENT ACROSS NORTHERN/EASTERN IOWA AND EXPECT THIS AREA OF PRECIP TO SHIFT EASTWARD THROUGH THE EARLY MORNING HOURS AND MOVE ACROSS THE TERMINALS LATER THIS MORNING. WITH FAVORABLE METEOROLOGICAL CONDITIONS AND LATEST SHORT TERM GUIDANCE SHIFTING THIS PRECIP EAST THROUGH THE AREA...FELT COMFORTABLE ADDING IN A PREVAILING GROUP FOR AT LEAST SHOWERS FOR ALL OF THE TERMINALS THIS MORNING WHILE ALSO ADDING IN A TEMPO GROUP FOR POSSIBLE THUNDER THROUGH MID MORNING. SHOULD THEN OBSERVE THIS PRECIP EXIT TO THE EAST WITH A LULL IN THE ACTIVITY...BEFORE REDEVELOPMENT OCCURS WITH AN APPROACHING FRONT LATER THIS AFTERNOON. DO FEEL THAT SHOWERS/THUNDERSTORMS WILL DEVELOP AROUND THE AREA LATER THIS AFTERNOON...BUT CONFIDENCE IS LOWER WITH REGARDS TO TIMING/COVERAGE AND EVEN TS POTENTIAL. WILL CONTINUE TO MONITOR THIS AFTERNOON ACTIVITY AND ADJUST AS NEEDED. EXPECT SOUTHERLY WINDS THIS FORECAST PERIOD WITH A TREND MORE TOWARDS THE WEST SOUTHWEST THROUGH MID DAY...WHILE SPEEDS INCREASE AND SPORADIC GUSTS DEVELOP. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE WITH WIDELY SCATTERED SHOWERS/TS IN THE NEAR TERM. * HIGH CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS COVERAGE AND TIMING LATER THIS AFTERNOON. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY. MVFR/GUSTY WINDS POSSIBLE. * WEDNESDAY...CHANCE OF TSRA. * THURSDAY THROUGH SATURDAY...DRY/VFR. && .MARINE... 232 PM CDT HIGH PRESSURE OVER HUDSON BAY WILL MOVE NORTHEASTWARD TONIGHT WHILE SEVERAL AREAS OF LOW PRESSURE STRETCHING FROM SOUTHERN MANITOBA INTO THE UPPER MISSISSIPPI RIVER VALLEY AND BACK INTO THE SOUTHERN HIGH PLAINS EVOLVES. THE STRONGEST LOW IS OVER LAKE MANITOBA THIS AFTERNOON AND WILL MAKE ITS WAY TO DEVELOP NORTHWARD AS AN UPPER TROUGH REACHES IT TONIGHT AND MONDAY. THE NEXT AREA OF LOW PRESSURE IS MORE OF A TROUGH THAT EXTENDS FROM CENTRAL MINNESOTA TO THE U.P. OF MICHIGAN AND EASTERN LAKE SUPERIOR. AS THE HIGH TO THE NORTHEAST DEPARTS THIS LOW WILL MOVE NORTHEAST AND WEAKEN BUT WILL HAVE ENOUGH ENERGY TO PUSH A FRONTAL BOUNDARY SOUTHWARD ACROSS NORTHERN LAKE MICHIGAN TONIGHT. THE PRESSURE PATTERN WILL WEAKEN AS THE UPPER FLOW FLATTENS. THE FRONT WILL CONTINUE SOUTHWARD BUT WEAKEN AS IT DOES SO INTO TUESDAY LEAVING A LIGHT FLOW PATTERN OVER MUCH OF THE LAKE. IN THE MEANTIME...INCREASINGLY WARM AND MOIST AIR WILL RETURN TO THE LAKE LIKELY ALLOWING THE COVERAGE OF HAZE/FOG TO INCREASE INTO MONDAY AND TUESDAY. AT THE MOMENT...THE LOWER VSBY SEEMS TO BE CONFINED TO PORTIONS OF THE NORTHERN WISCONSIN SHORELINE. THE FRONT DOES NOT BRING MUCH OF A PUSH OF DRIER OR COOLER AIR SO DESPITE ITS PASSAGE ACROSS NORTHERN AND CENTRAL PARTS OF THE LAKE THE FOG DOES LOOK TO TRY AN EXPAND. ANOTHER SERIES OF UPPER TROUGHS WILL MOVE INTO THE WESTERN U.S. AND CANADA BY THIS TIME TRIGGERING NEW SURFACE LOW PRESSURE DEVELOPMENT ACROSS THE CENTRAL AND NORTHERN HIGH PLAINS WHICH THEN CROSSES OVER OR JUST NORTH OF THE LAKE INTO WEDNESDAY. THIS WILL PUSH A COOL FRONT ACROSS THE LAKE WHICH WILL THEN BE FOLLOWED BY A LARGE AREA OF HIGH PRESSURE. THIS WILL LEAD TO A PERIOD OF NORTHERLY WINDS BEHIND THE FRONT WITH A TRANSITION TO LIGHT AND VARIABLE WINDS AS THE HIGH MOVES CLOSER LATE IN THE WEEK. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
336 AM CDT MON JUL 8 2013 .DISCUSSION... 330 AM CDT THE FORECAST CHALLENGES ARE PRIMARILY WITHIN THE NEXT 48 HOURS AS THE AREA HAS BEEN OVERTAKEN BY THE SOUPIEST AIR MASS OF THE SEASON...IN FACT THE MOST PROLONGED HIGH DEW POINT EPISODE SINCE THE HEAT WAVE JUST OVER ONE YEAR AGO /JUL 4-7/. WITH THIS COMES SEVERE STORM AND HEAVY RAIN POTENTIAL...MORE SO ON TUESDAY. IN ADDITION...THE HIGHEST HEAT INDICES OF THE SEASON ARE FORECAST...AND WHILE NOT AT ADVISORY CRITERIA THESE LOOK TO FLIRT WITH 100 DEGREES IN SOME SOUTHERN CWA LOCATIONS ON TUESDAY AFTERNOON. SYNOPSIS...THE UPPER LEVEL RIDGE ACROSS THE CENTRAL AND SOUTHERN PLAINS IS EVOLVING EAST EARLY THIS MORNING WITH TURBULENT MOIST FLOW AROUND ITS NORTHERN PERIPHERY. NUMEROUS AREAS OF CONVECTION ARE PRESENT ASSOCIATED WITH SHORT WAVE ASCENT AND MOIST ADVECTION ON THE LOW-LEVEL JET. A WEAK LOW-LEVEL TROUGH IS PRESENT FROM NORTHERN WI TO NORTHERN KS. TO THE EAST AND SOUTH OF THIS FEATURE...UPPER 60S TO MID 70S DEW POINTS PREVAIL ON MOST OBSERVATIONS ALL THE WAY TO THE ATLANTIC AND GULF COASTS. THE RIDGE WILL TRY TO EXPAND INTO THE AREA THIS AFTERNOON AND MORE SO TONIGHT WITH CONTINUED SYNOPTIC SOUTHERLY SURFACE FLOW ACROSS THE AREA. THE SURFACE TROUGH WILL WORK ITS WAY LIKELY INTO FAR SOUTHERN WI BY LATE AFTERNOON. TWO SURFACE LOWS LOOK TO RIDE ALONG THIS...ONE DURING THE DAY TUE ASSOCIATED WITH A STRONG SHORT WAVE EXITING THE GREAT BASIN EARLY THIS MORNING...AND ANOTHER STRONGER SURFACE LOW ASSOCIATED WITH AN UPPER TROUGH THAT WILL DEVELOP INTO THE GREAT LAKES BY LATE TUE NIGHT. THIS SECOND WAVE WILL USHER A COOL FRONT THROUGH THE AREA WED MORNING WITH THE SOMEWHAT COOLER/DRIER AIR BEING REALIZED BY WED NIGHT. THIS MORNING...IT APPEARS THERE ARE TWO IMMEDIATE UPSTREAM SHORT WAVES...ONE BETTER DEFINED ONE PER WATER VAPOR AND RADAR MOSAIC ACROSS NORTHEAST IA...AND ANOTHER ACROSS FAR SOUTHERN IA/NORTHERN MO. TOGETHER THESE WILL MOVE EAST AND LOOK TO SLOWLY WEAKEN LATER THIS MORNING ACROSS THE EASTERN FORECAST AREA WITH THE MORE DOMINANT JET TO THE NORTH. PROFILER DATA INDICATES 35 KT 850-925MB FLOW INTO THE AREA WHICH LOOKS TO CONTINUE PAST DAYBREAK. SO EXPECT THAT SHOWER AND EMBEDDED STORM ACTIVITY WILL BE SUSTAINED AS FAR EAST AS CHICAGO BY MID-MORNING. THE HRRR SEEMS TO HAVE A FIRM HANDLE ON THE ONGOING CONVECTION AND ITS EVOLUTION MAKES SENSE AND HAVE FOLLOWED CLOSELY IN OUR FORECAST HOURLY POPS. HAVE SEEN A COUPLE 20 KT PLUS GUSTS IN SW WI INDICATING THAT A COLD POOL MAY BE TRYING TO DEVELOP. THIS AND ANY MCV DEVELOPMENT WOULD ALSO AID IN SUSTAINING THE ACTIVITY EASTWARD. SEVERE POTENTIAL IS MAINLY LOW WITH THIS THROUGH THE MORNING AND RADAR TRENDS FROM ARX/DVN CONFIRM NOTHING POTENT IN THE STORM BEHAVIORS...THOUGH CANT RULE OUT SMALL HAIL OR GUSTY WINDS. IN ADDITION...STORMS WILL BE VERY EFFICIENT RAIN PRODUCERS GIVEN HIGH ATMOSPHERIC MOISTURE CONTENT /PWATS AOA 1.65 INCHES AND 700MB TDS AOA 4C/. CONFIDENCE...HIGH. THIS AFTERNOON AND TONIGHT...WITH THE PRIMARY SHORT WAVE IMPULSES HAVING MOVED EAST...COVERAGE OF PRECIP SHOULD AT LEAST TEMPORARILY DIMINISH IN THE EARLY AFTERNOON. OUTFLOW BOUNDARIES FROM THE MORNING ACTIVITY...EVEN IF ELEVATED COULD CONTINUE FESTERING CONVECTION THIS AFTERNOON GIVEN ATTAINABLE CONVECTIVE TEMPS. THIS WOULD SEEM MOST FAVORED ALONG AND SOUTH OF I-80. THE SURFACE BOUNDARY WILL BE NEAR THE IL/WI STATE LINE...AND SIMILAR TO PREV FORECAST REASONING COULD SEE SOME SCATTERED DEVELOPMENT LATER THIS AFTERNOON ALONG THAT AS WELL. AFTER WHAT WILL LIKELY BE A SLOW TEMPERATURE CLIMB THIS MORNING...THIS AFTERNOON SHOULD SEE RECOVERY INTO THE UPPER 80S AND MAYBE EVEN 90...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA. WITH SUCH HIGH DEW POINT AIR...SURFACE BASED INSTABILITY OF 1500-2500 J/KG WOULD BE SUPPORTED BY THESE FORECAST TEMPS AND DEW POINTS. MOST GUIDANCE DOES HAVE A SPLOTCHY QPF PRODUCED OVER THE AREA. ANY SCATTERED CONVECTION THAT CAN DEVELOP THIS AFTERNOON INTO THE EVE WOULD HAVE SOME SEVERE WEATHER THREAT. THE HIGH PWAT AIR WILL SUPPORT HEAVY RAIN ALONG WITH PRECIP LOADING CONCERNS TOWARDS ISOLATED DOWNBURSTS IN ANY MORE ROBUST CELLS OR MULTI-CELL CLUSTERS...BUT OVERALL THREAT COVERAGE IS LOW. AS WE HEAD TO AFTER SUNDOWN...HEIGHT FALLS AND THE LLJ NOSE CONTINUE TO BE FOCUSED TO THE NORTHWEST OF THE AREA /OVER MN AND NORTHERN IA/. THIS IS WHERE LIKELY MCS DEVELOPMENT WILL OCCUR LATE. IN ADVANCE...BROAD WARM AND MOIST ADVECTION ALOFT MAY ALLOW FOR ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT OVER THE AREA. DEEP WARM CLOUD PROCESSES WILL BE AT PLAY WITH PWATS CONTINUING TO INCH UP...MEANING HEAVY RAIN WILL BE THE GREATEST THREAT. GIVEN A SOMEWHAT DIFFUSE 850MB BAROCLINIC ZONE AND FORWARD PROPAGATION INDICATED...THE TRAINING SETUP IS SOMEWHAT MARGINAL IN THE FORECAST AREA AT LEAST PRIOR TO DAYBREAK TUE. SO NO FLASH FLOOD WATCH BEING ISSUED AT THIS TIME BUT THIS WILL NEED TO BE MONITORED. CONFIDENCE...MEDIUM. TUESDAY AND TUESDAY NIGHT...THESE ARE THE PERIODS WITH THE GREATER POTENTIAL FOR HIGHER IMPACT WEATHER. MANY MODELS IN THE SUITE OF GUIDANCE CONTINUE TO ADVERTISE A PRIMARY MCS DEVELOPING BY TUE MORNING AHEAD OF A STRONG IMPULSE. THERE ARE VARIANCES IN LATITUDE ON THIS...BUT CERTAINLY THE PATTERN WOULD SUPPORT SUCH EVOLUTION WITH AMPLE INSTABILITY AHEAD OF AN MCS EVEN IN THE MORNING GIVEN THE HIGH ABSOLUTE MOISTURE. THE SPC HAS OUTLOOKED A 30 PERCENT AREA FOR THEIR DAY TWO OUTLOOK FOR THIS REASON AND THE AREA THEY INDICATED IS WHAT HAS BEEN FAVORED IN OUR FORECAST. IT IS INTERESTING TO NOTE THAT THE CIPS ANALOG GUIDANCE FOR MULTIPLE DAYS HAS INDICATED MATCHES ON SEVERE WIND EVENTS FROM NORTHERN IA INTO SOUTHERN WI AND FAR NORTHERN IL AND CONTINUES TO DO SUCH BASED ON THE NAM FORECAST. SO THE MOST FAVORED AREA WOULD LIKELY BE NORTH OF I-80...AND MAYBE EVEN NORTH OF I-88 FOR POTENTIALLY A STRONG WIND COMPLEX ON TUE. SOME OF THE SLOWER GUIDANCE HAS THIS EVEN HAPPENING IN THE AFTERNOON. CONFIDENCE ON EXACT DEVELOPMENT BY AFTERNOON AND NIGHTTIME DROPS...ESPECIALLY IF ANYTHING CAN SPARK OFF OUTFLOWS. CERTAINLY A SEVERE WEATHER POTENTIAL EXISTS THROUGH THE REST OF THE DAY WITH GRADUALLY INCREASING DEEP LAYER SHEAR AND PLENTY OF INSTABILITY. THE SOUTHERN FORECAST AREA COULD WARM INTO THE LOWER TO MID 90S. RIGHT NOW HEAD INDICES ARE FORECAST AROUND 100 FOR MULTIPLE AFTERNOON HOURS IN THE SOUTHERN FORECAST AREA...WHILE AROUND THE MID 90S IN ROCKFORD AND CHICAGO THOUGH CONFIDENCE THERE IS LOW BASED ON PROBABLE MORNING/EARLY AFTERNOON CONVECTION. HAVE MENTIONED HEAVY RAIN IN THE FORECAST FOR TUE AND TUE NIGHT GIVEN THE ATMOSPHERIC SETUP AND DO HAVE CHC SEVERE MENTIONED IN FAR NORTHERN IL GIVEN THE CONSISTENT SIGNAL AND PATTERN SUPPORT FOR AT THE LEAST A NEARBY MCS. CONFIDENCE...OVERALL MEDIUM. WEDNESDAY...THE COOL FRONT...OR AT LEAST THE WIND SHIFT IS MAINLY AGREED ON BY GUIDANCE TO BE MOVING SOUTHEAST THROUGH THE AREA EARLY WED. THE COOLER TEMPERATURES IN THE MIX DOWN LAYER LOOK TO ARRIVE LATE IN THE AFTERNOON INTO THE EVE...SO HIGHS IN THE MID TO UPPER 80S ARE STILL FORECAST. SOME ONGOING CONVECTION IS LIKELY IN THE SOUTHEAST CWA AT LEAST ON WED MORNING...THOUGH COVERAGE IS TOUGH TO TELL AT THIS POINT. DEW POINTS LOOK TO FALL BY WED EVE. CONFIDENCE...HIGH. EXTENDED...HAVE NOT MADE TOO MANY CHANGES FROM A SMART BLEND OF GUIDANCE WITH GOING FORECAST. THIS PERIOD LOOKS MAINLY QUIET AS THE PATTERN EVOLVES THROUGH THE WEEKEND TO ONCE AGAIN A BLOCKED SETUP. SURFACE HIGH PRESSURE LOOKS TO PREVAIL WITH ONSHORE FLOW INTO CHICAGOLAND AND NORTHWEST INDIANA. THIS SHOULD OFFER ONLY MINIMAL COOLING THOUGH WITH BASICALLY TEMPERATURES AT OR JUST BELOW SEASONAL NORMALS IN MOST PLACES. CONFIDENCE...HIGH. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * WIDELY SCATTERED SHOWERS WITH ISOLATED TS EARLY THIS MORNING...WITH LIMITED OR NO VIS RESTRICTION EXPECTED. * BETTER CHANCES FOR SHOWERS AND TS ARRIVE LATER THIS MORNING AROUND 13-14Z...WITH MVFR VIS POSSIBLE. * CHANCES FOR SHOWERS AND POSSIBLE TS ONCE AGAIN LATER THIS AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... AS SEVERAL MID LEVEL DISTURBANCES APPROACH FROM THE WEST...LATEST RADAR IMAGERY SHOWING SCATTERED SHOWER DEVELOPMENT OCCURRING ACROSS NORTHWEST ILLINOIS EARLY THIS MORNING. EXPECT THIS SCATTERED DEVELOPMENT ALONG WITH ISOLATED TS TO PERSIST EARLY THIS MORNING...BUT WITH LITTLE IMPACTS TO THE TERMINALS EXPECTED. AM MONITORING SHOWER/TS DEVELOPMENT ACROSS NORTHERN/EASTERN IOWA AND EXPECT THIS AREA OF PRECIP TO SHIFT EASTWARD THROUGH THE EARLY MORNING HOURS AND MOVE ACROSS THE TERMINALS LATER THIS MORNING. WITH FAVORABLE METEOROLOGICAL CONDITIONS AND LATEST SHORT TERM GUIDANCE SHIFTING THIS PRECIP EAST THROUGH THE AREA...FELT COMFORTABLE ADDING IN A PREVAILING GROUP FOR AT LEAST SHOWERS FOR ALL OF THE TERMINALS THIS MORNING WHILE ALSO ADDING IN A TEMPO GROUP FOR POSSIBLE THUNDER THROUGH MID MORNING. SHOULD THEN OBSERVE THIS PRECIP EXIT TO THE EAST WITH A LULL IN THE ACTIVITY...BEFORE REDEVELOPMENT OCCURS WITH AN APPROACHING FRONT LATER THIS AFTERNOON. DO FEEL THAT SHOWERS/THUNDERSTORMS WILL DEVELOP AROUND THE AREA LATER THIS AFTERNOON...BUT CONFIDENCE IS LOWER WITH REGARDS TO TIMING/COVERAGE AND EVEN TS POTENTIAL. WILL CONTINUE TO MONITOR THIS AFTERNOON ACTIVITY AND ADJUST AS NEEDED. EXPECT SOUTHERLY WINDS THIS FORECAST PERIOD WITH A TREND MORE TOWARDS THE WEST SOUTHWEST THROUGH MID DAY...WHILE SPEEDS INCREASE AND SPORADIC GUSTS DEVELOP. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE WITH WIDELY SCATTERED SHOWERS/TS IN THE NEAR TERM. * MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS COVERAGE AND TIMING LATER THIS AFTERNOON. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY. MVFR/GUSTY WINDS POSSIBLE. * WEDNESDAY...CHANCE OF TSRA. * THURSDAY THROUGH SATURDAY...DRY/VFR. && .MARINE... 232 PM CDT HIGH PRESSURE OVER HUDSON BAY WILL MOVE NORTHEASTWARD TONIGHT WHILE SEVERAL AREAS OF LOW PRESSURE STRETCHING FROM SOUTHERN MANITOBA INTO THE UPPER MISSISSIPPI RIVER VALLEY AND BACK INTO THE SOUTHERN HIGH PLAINS EVOLVES. THE STRONGEST LOW IS OVER LAKE MANITOBA THIS AFTERNOON AND WILL MAKE ITS WAY TO DEVELOP NORTHWARD AS AN UPPER TROUGH REACHES IT TONIGHT AND MONDAY. THE NEXT AREA OF LOW PRESSURE IS MORE OF A TROUGH THAT EXTENDS FROM CENTRAL MINNESOTA TO THE U.P. OF MICHIGAN AND EASTERN LAKE SUPERIOR. AS THE HIGH TO THE NORTHEAST DEPARTS THIS LOW WILL MOVE NORTHEAST AND WEAKEN BUT WILL HAVE ENOUGH ENERGY TO PUSH A FRONTAL BOUNDARY SOUTHWARD ACROSS NORTHERN LAKE MICHIGAN TONIGHT. THE PRESSURE PATTERN WILL WEAKEN AS THE UPPER FLOW FLATTENS. THE FRONT WILL CONTINUE SOUTHWARD BUT WEAKEN AS IT DOES SO INTO TUESDAY LEAVING A LIGHT FLOW PATTERN OVER MUCH OF THE LAKE. IN THE MEANTIME...INCREASINGLY WARM AND MOIST AIR WILL RETURN TO THE LAKE LIKELY ALLOWING THE COVERAGE OF HAZE/FOG TO INCREASE INTO MONDAY AND TUESDAY. AT THE MOMENT...THE LOWER VSBY SEEMS TO BE CONFINED TO PORTIONS OF THE NORTHERN WISCONSIN SHORELINE. THE FRONT DOES NOT BRING MUCH OF A PUSH OF DRIER OR COOLER AIR SO DESPITE ITS PASSAGE ACROSS NORTHERN AND CENTRAL PARTS OF THE LAKE THE FOG DOES LOOK TO TRY AN EXPAND. ANOTHER SERIES OF UPPER TROUGHS WILL MOVE INTO THE WESTERN U.S. AND CANADA BY THIS TIME TRIGGERING NEW SURFACE LOW PRESSURE DEVELOPMENT ACROSS THE CENTRAL AND NORTHERN HIGH PLAINS WHICH THEN CROSSES OVER OR JUST NORTH OF THE LAKE INTO WEDNESDAY. THIS WILL PUSH A COOL FRONT ACROSS THE LAKE WHICH WILL THEN BE FOLLOWED BY A LARGE AREA OF HIGH PRESSURE. THIS WILL LEAD TO A PERIOD OF NORTHERLY WINDS BEHIND THE FRONT WITH A TRANSITION TO LIGHT AND VARIABLE WINDS AS THE HIGH MOVES CLOSER LATE IN THE WEEK. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
300 AM CDT MON JUL 8 2013 .DISCUSSION... ISSUED 300 AM CDT MON JUL 8 2013 WARM AND HUMID CONDITIONS WITH PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PREVAIL FOR THE NEXT COUPLE OF DAYS...BEFORE COOLER AND DRIER WEATHER ARRIVES BY THE END OF THE WEEK. 07Z/2AM SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED OVER WESTERN WISCONSIN...WITH NEARLY STATIONARY BOUNDARY EXTENDING SOUTHWESTWARD INTO NEBRASKA. CONVECTION HAS DEVELOPED ALONG THIS BOUNDARY...AIDED BY A SUBTLE 500MB SHORT-WAVE OVER MINNESOTA AND A 30-35KT 850MB JET FROM THE SOUTHERN PLAINS INTO IOWA. SHORT TERM...TODAY THROUGH WEDNESDAY 00Z MODELS ARE PERFORMING VERY POORLY THUS FAR...WITH NONE OF THEM ADEQUATELY SHOWING THE CURRENT CONVECTION TO THE N/NW OF ILLINOIS. ONLY THE 05Z HRRR HAS A REASONABLE HANDLE ON THE SITUATION...SO WILL FOLLOW ITS SOLUTION CLOSELY FOR THE IMMEDIATE SHORT-TERM FORECAST. HRRR SHOWS A LINE OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN IOWA/FAR NORTHERN MISSOURI OVER THE NEXT COUPLE OF HOURS...THEN PUSHES THE LINE INTO THE NORTHERN KILX CWA AFTER 10Z. GIVEN 30KT LOW-LEVEL JET ORIENTED FROM KANSAS E/NE INTO WESTERN ILLINOIS THIS MORNING...THINK THIS IS A PLAUSIBLE SOLUTION. RADAR MOSAIC IS ALREADY SHOWING A BROKEN LINE OF CONVECTION DEVELOPING ALONG/WEST OF THE MISSISSIPPI RIVER...SO HAVE BUMPED POPS TO LIKELY ALONG AND NORTHWEST OF A RUSHVILLE TO BLOOMINGTON-NORMAL LINE THIS MORNING. AS LOW-LEVEL JET WEAKENS AND SHIFTS BACK WESTWARD...SHOWERS/THUNDER WILL TEND TO DISSIPATE LATER THIS MORNING AS IT SAGS SOUTHEASTWARD TOWARD THE I-72 CORRIDOR. WILL CARRY CHANCE POPS AS FAR SOUTH AS A SPRINGFIELD TO MATTOON LINE ACCORDINGLY...WITH ONLY SLIGHT CHANCES FOR ISOLATED THUNDER ACROSS THE FAR SE CWA THIS AFTERNOON. WILL BE A VERY WARM AND HUMID DAY...WITH HIGHS REACHING THE UPPER 80S AND LOWER 90S. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES TONIGHT...WITH TRAILING FRONTAL BOUNDARY SINKING SLIGHTLY FURTHER SOUTHWARD TO NEAR THE ILLINOIS/WISCONSIN BORDER. SCATTERED SHOWERS/THUNDER WILL PERSIST NEAR THE BOUNDARY...RESULTING IN LOW CHANCE POPS FOR THE NORTHERN TWO-THIRDS OF THE CWA TONIGHT. FURTHER SOUTH...LITTLE OR NO PRECIP IS ANTICIPATED ALONG/SOUTH OF I-70. AS LOW-LEVEL JET STRENGTHENS AND SHORT-WAVE CURRENTLY OVER UTAH TRACKS E/NE INTO THE NORTHERN PLAINS...AN MCS WILL LIKELY DEVELOP OVER SOUTHERN MINNESOTA/NORTHERN IOWA LATE TONIGHT. TRAJECTORIES TAKE THIS SYSTEM MAINLY EASTWARD ACROSS WISCONSIN AND NORTHERN ILLINOIS TUESDAY MORNING. THINK BULK OF THE CONVECTION WILL REMAIN JUST NORTH OF CENTRAL ILLINOIS...PRIMARILY ALONG/NORTH OF I-80. WILL FEATURE HIGHEST POPS ACROSS THE NORTHERN CWA ACCORDINGLY...WITH ONLY LOW CHANCE TO SLIGHT CHANCE POPS ACROSS THE CENTRAL AND SOUTHERN ZONES. MAIN STORY ON TUESDAY WILL BE THE HEAT AND HUMIDITY. AFTERNOON HIGH TEMPERATURES IN THE LOWER 90S COMBINED WITH DEWPOINTS IN THE LOWER TO MIDDLE 70S...WILL RESULT IN HEAT INDEX VALUES APPROACHING 100 DEGREES. BEST CHANCE FOR WIDESPREAD CONVECTION STILL ON TARGET FOR TUESDAY NIGHT INTO WEDNESDAY...AS NORTHERN STREAM WAVE CURRENTLY OVER THE PACIFIC NORTHWEST PUSHES COLD FRONT SOUTHWARD INTO CENTRAL ILLINOIS. WITH FRONT INTERACTING WITH A VERY MOIST AIRMASS CHARACTERIZED BY PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES...WILL CONTINUE TO FEATURE LIKELY POPS WITH FROPA. SEVERE WEATHER THREAT REMAINS UNCERTAIN...HOWEVER LOCALLY HEAVY RAINFALL WILL BE A GOOD BET WITH THE STORMS LATE TUESDAY NIGHT INTO WEDNESDAY. FRONT WILL DROP SOUTHWARD INTO THE OHIO RIVER VALLEY BY WEDNESDAY EVENING...ENDING THE THREAT FOR RAIN FROM NORTH TO SOUTH ACROSS THE AREA. WILL LINGER CHANCE POPS ALONG/SOUTH OF I-70 THROUGH WEDNESDAY EVENING...THEN WILL GO DRY ACROSS THE BOARD AFTER MIDNIGHT. LONG TERM...THURSDAY THROUGH SUNDAY COOLER/DRIER WEATHER WILL PREVAIL THROUGH THE EXTENDED...AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES. HIGH TEMPERATURES WILL ONLY REACH THE LOWER TO MIDDLE 80S...WHILE OVERNIGHT LOWS DROP INTO THE LOWER TO MIDDLE 60S. BARNES && .AVIATION... ISSUED 1152 PM CDT SUN JUL 7 2013 A FEW SPOTTY SHOWERS HAVE COME AS CLOSE AS NORTHWEST ILLINOIS...AND MID/HIGH LEVEL CLOUDINESS IS ON THE INCREASE ACROSS THE CENTRAL ILLINOIS TERMINALS. HOWEVER...THE BULK OF THE SHOWERS/STORMS ARE STILL WELL TO THE NORTHWEST...ALONG A LINE EXTENDING FROM NORTHERN WISCONSIN INTO WESTERN NEBRASKA. IF THE MORE SOLID LINE HOLDS TOGETHER...IT MAY IMPACT KPIA AND KBMI A LITTLE AFTER SUNRISE. EVEN IF THE STORMS DO NOT MAKE IT INTO THE AREA BEFORE DRYING UP...THERE IS A CHANCE FOR AN OUTFLOW BOUNDARY FROM THESE STORMS SERVING AS A FOCUS FOR STORMS WITH THE HEATING OF THE DAY MONDAY. IN ANY EVENT...CONFIDENCE IN THE TIMING/COVERAGE OF CONVECTION IS TOO LOW TO MENTION IN MOST TERMINALS. HAVE CONTINUED WITH AN EARLY MORNING VCSH AT KPIA/KBMI AS THIS AREA WILL BE CLOSEST TO THE NOCTURNAL STORMS THAT SHOULD BE DECAYING AS THEY APPROACH. VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD OUTSIDE OF ANY STORMS. BAK && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
750 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 455 PM EDT TUE JUL 9 2013 THUNDERSTORMS TONIGHT AND EARLY WEDNESDAY WILL END OVER MOST AREAS BY EARLY WEDNESDAY NIGHT. LOWS TONIGHT WILL BE MUGGY...IN THE 70S...BUT WILL BE CONSIDERABLY COOLER WEDNESDAY NIGHT. TEMPERATURES WILL RETURN TO A LITTLE ABOVE NORMAL BY THIS WEEKEND AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. CONDITIONS WILL REMAIN DRY AFTER THE STORMS END EARLY WEDNESDAY NIGHT. && .UPDATE... ISSUED AT 651 PM EDT TUE JUL 9 2013 CONVECTION EARLIER THIS AFTERNOON HAS HELPED STABILIZE THE NORTHERN HALF OF OUR CWA...WHILE MLCAPES STILL HOVER AROUND 2000 J/KG IN OUR EXTREME SOUTH. A FEW STRONG STORMS REMAIN POSSIBLE IN THIS AREA BUT FORCING IS WEAK AND DEEP LAYER SHEAR IS ONLY AROUND 20 KTS SO CONVECTION WILL REMAIN ISOLATED AND PULSEY THROUGH THE REST OF THE EVENING. LATEST WATER VAPOR LOOP AND MSAS ANALYSIS SHOW MAIN MIDLEVEL HEIGHT FALLS AND ASSOCIATED COLD FRONT REMAIN WELL NORTHWEST OF HERE. THERE IS ALSO A WEAK AREA OF SUBSIDENCE AND SOME MIDLEVEL DRY AIR AHEAD OF THIS COLD FRONT THAT IS HELPING TO SUPPRESS CONVECTION ACROSS IOWA DESPITE DECENT INSTABILITY. A FEW STORMS HAVE FIRED ACROSS WISCONSIN BUT THE PROSPECTS FOR AN ORGANIZED MCS TO DEVELOP AND PROPAGATE INTO OUR AREA AS SUGGESTED BY SOME EARLIER HI-RES RUNS APPEAR TO BE DWINDLING. LLJ WILL BEGIN TO RAMP UP LATER TONIGHT THOUGH AND THIS ENHANCED CONVERGENCE AHEAD OF THE APPROACHING COLD FRONT WILL HELP SUPPORT SOME PRECIP LATER TONIGHT WITH ABOUT 1000 J/KG OF ELEVATED INSTABILITY. WILL TAKE SOME TIME FOR THIS ACTIVITY TO REACH OUR CWA...PROBABLY AFTER MIDNIGHT...AND THE LATEST HRRR KEEPS CONVECTION FAIRLY SCATTERED. GIVEN POOR MIDLEVEL LAPSE RATES...WEAK FORCING...AND LACK OF CONVECTION/STABLE CONDITIONS IMMEDIATELY UPSTREAM WILL BE ADDING SOME DETAIL TO THE POP GRIDS FOR THIS EVENING AND SCALING BACK TO SCT/CHANCE WORDING FOR THE ENTIRE OVERNIGHT PERIOD. WIDESPREAD SEVERE WEATHER NOT EXPECTED DUE TO ELEVATED NATURE OF STORMS...MARGINAL MUCAPE VALUES...AND WEAK SHEAR. WILL LEAVE THE FLASH FLOOD WATCH UP THOUGH AS ANY SUSTAINED UPDRAFTS/TRAINING STORMS COULD PRODUCE A LOCALIZED FLOODING THREAT WITH SUCH A MOIST AIRMASS IN PLACE...PWATS STILL HOVERING AROUND 2 INCHES. UPDATED ZFP WILL BE OUT SOON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 THUNDERSTORMS WERE CONTINUING TO DEVELOP IN A VERY UNSTABLE AIRMASS AHEAD OF AN APPROACHING UPPER LEVEL TROF AND COLD FRONT. SPC MESO ANALYSIS SHOWS PRECIP WATER VALUES EXCEEDING 2.2 INCHES OVER NRN INDIANA. HOWEVER...MID LEVEL LAPSE RATES OF 5.5 C/KM WERE REALLY LIMITING CONVECTIVE EXTENT UPSTREAM AND MAY BE A SIGNIFICANT FACTOR TONIGHT IN THE DEVELOPMENT OF MORE CONVECTION. FOR THIS PACKAGE... FAVORED MAINLY THE HIGH RES WPC MODELS...ESPECIALLY 4KM NAM. HAVE ADDED A FLASH FLOOD WATCH OVER NW OHIO WHERE 3 HOUR FLASH FLOOD GUIDANCE WAS DOWN TO ABOUT 1.0 INCH OVER SOME COUNTIES WHERE RECENT RAINFALL OF SEVERAL INCHES HAS OCCURRED. IT LOOKS TO BE HARD FOR STORMS TO PRODUCE SEVERE WEATHER LATER TODAY OR TONIGHT GIVEN A VERY HIGH WET BULB ZERO OVER 13K AND LOW BULK SHEAR WITH STABLE MID LEVEL LAPSE RATES. CURRENT THINKING WIND GUSTS SHOULD TOP OUT AROUND 40 MPH. SOME LINGERING STORMS ARE POSSIBLE WEDNESDAY...BUT GIVEN OVERNIGHT CONVECTION... LOW LEVEL CONDITIONS SHOULD BECOME TOO STABLE TO SUPPORT SEVERE STORMS. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 SHRTWV MOVG INTO THE NRN PLAINS THIS AFTN EXPECTED TO BE LOCATED OVER THE GRTLKS/OH VALLEY WED EVE. ACCOMPANYING SFC CDFNT SHOULD BE JUST SE OF SERN PORTION OF CWA. A SLIGHT CHC OF SHOWERS/TSTMS LINGERING INTO WED EVE WAS MAINTAINED OVER EXTREME SE. CAA/SUBSIDENCE BEHIND THIS SYSTEM WILL RESULT IN DIMINISHING CLOUD COVER WITH COOLER AND LESS HUMID CONDITIONS WED NIGHT AND THU. FAIR WX WILL CONT THU NGT-FRI AS SFC HIGH MOVES SLOWLY EAST ACROSS THE GRTLKS. WK WAA EXPECTED OVER THE WEEKEND AS GRTLKS HIGH MOVES EAST ACROSS NEW ENGLAND AND MERGES WITH STRONG WRN ATLANTIC ANTICYCLONE. THIS ALONG WITH UPR LEVEL RIDGE EXPANDING NEWD FROM THE SRN ROCKIES/PLAINS TOWARD THE GRTLKS SHOULD RESULT IN A WARMING TREND AND DRY CONDITIONS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 735 PM EDT TUE JUL 9 2013 DRY AND LARGELY STABLE CONDITIONS ARE CURRENTLY IN PLACE ACROSS THE LOCAL AREA THANKS TO EARLIER PASSING CONVECTION. A WEAK COLD FRONT WILL APPROACH THE AREA BY LATER TONIGHT AND ASSOCIATED CONVERGENCE COUPLED WITH LINGERING ELEVATED INSTABILITY MAY GENERATE A FEW MORE SHOWERS AND THUNDERSTORMS. LATEST HI-RES MODELS SUGGEST THIS ACTIVITY WILL REMAIN FAIRLY SCATTERED THOUGH AND CONFIDENCE IN THUNDERSTORMS IMPACTING THE TERMINALS IS NOT HIGH. VFR CONDITIONS EXPECTED TOMORROW AS A LARGE HIGH PRESSURE SYSTEM ADVECTS COOLER AND DRIER AIR INTO THE REGION. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR OHZ001-002-004- 005-015-016-024-025. LM...NONE. && $$ UPDATE...AGD SYNOPSIS...SKIPPER SHORT TERM...SKIPPER LONG TERM...JT AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
733 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 455 PM EDT TUE JUL 9 2013 THUNDERSTORMS TONIGHT AND EARLY WEDNESDAY WILL END OVER MOST AREAS BY EARLY WEDNESDAY NIGHT. LOWS TONIGHT WILL BE MUGGY...IN THE 70S...BUT WILL BE CONSIDERABLY COOLER WEDNESDAY NIGHT. TEMPERATURES WILL RETURN TO A LITTLE ABOVE NORMAL BY THIS WEEKEND AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. CONDITIONS WILL REMAIN DRY AFTER THE STORMS END EARLY WEDNESDAY NIGHT. && .UPDATE... ISSUED AT 651 PM EDT TUE JUL 9 2013 CONVECTION EARLIER THIS AFTERNOON HAS HELPED STABILIZE THE NORTHERN HALF OF OUR CWA...WHILE MLCAPES STILL HOVER AROUND 2000 J/KG IN OUR EXTREME SOUTH. A FEW STRONG STORMS REMAIN POSSIBLE IN THIS AREA BUT FORCING IS WEAK AND DEEP LAYER SHEAR IS ONLY AROUND 20 KTS SO CONVECTION WILL REMAIN ISOLATED AND PULSEY THROUGH THE REST OF THE EVENING. LATEST WATER VAPOR LOOP AND MSAS ANALYSIS SHOW MAIN MIDLEVEL HEIGHT FALLS AND ASSOCIATED COLD FRONT REMAIN WELL NORTHWEST OF HERE. THERE IS ALSO A WEAK AREA OF SUBSIDENCE AND SOME MIDLEVEL DRY AIR AHEAD OF THIS COLD FRONT THAT IS HELPING TO SUPPRESS CONVECTION ACROSS IOWA DESPITE DECENT INSTABILITY. A FEW STORMS HAVE FIRED ACROSS WISCONSIN BUT THE PROSPECTS FOR AN ORGANIZED MCS TO DEVELOP AND PROPAGATE INTO OUR AREA AS SUGGESTED BY SOME EARLIER HI-RES RUNS APPEAR TO BE DWINDLING. LLJ WILL BEGIN TO RAMP UP LATER TONIGHT THOUGH AND THIS ENHANCED CONVERGENCE AHEAD OF THE APPROACHING COLD FRONT WILL HELP SUPPORT SOME PRECIP LATER TONIGHT WITH ABOUT 1000 J/KG OF ELEVATED INSTABILITY. WILL TAKE SOME TIME FOR THIS ACTIVITY TO REACH OUR CWA...PROBABLY AFTER MIDNIGHT...AND THE LATEST HRRR KEEPS CONVECTION FAIRLY SCATTERED. GIVEN POOR MIDLEVEL LAPSE RATES...WEAK FORCING...AND LACK OF CONVECTION/STABLE CONDITIONS IMMEDIATELY UPSTREAM WILL BE ADDING SOME DETAIL TO THE POP GRIDS FOR THIS EVENING AND SCALING BACK TO SCT/CHANCE WORDING FOR THE ENTIRE OVERNIGHT PERIOD. WIDESPREAD SEVERE WEATHER NOT EXPECTED DUE TO ELEVATED NATURE OF STORMS...MARGINAL MUCAPE VALUES...AND WEAK SHEAR. WILL LEAVE THE FLASH FLOOD WATCH UP THOUGH AS ANY SUSTAINED UPDRAFTS/TRAINING STORMS COULD PRODUCE A LOCALIZED FLOODING THREAT WITH SUCH A MOIST AIRMASS IN PLACE...PWATS STILL HOVERING AROUND 2 INCHES. UPDATED ZFP WILL BE OUT SOON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 THUNDERSTORMS WERE CONTINUING TO DEVELOP IN A VERY UNSTABLE AIRMASS AHEAD OF AN APPROACHING UPPER LEVEL TROF AND COLD FRONT. SPC MESO ANALYSIS SHOWS PRECIP WATER VALUES EXCEEDING 2.2 INCHES OVER NRN INDIANA. HOWEVER...MID LEVEL LAPSE RATES OF 5.5 C/KM WERE REALLY LIMITING CONVECTIVE EXTENT UPSTREAM AND MAY BE A SIGNIFICANT FACTOR TONIGHT IN THE DEVELOPMENT OF MORE CONVECTION. FOR THIS PACKAGE... FAVORED MAINLY THE HIGH RES WPC MODELS...ESPECIALLY 4KM NAM. HAVE ADDED A FLASH FLOOD WATCH OVER NW OHIO WHERE 3 HOUR FLASH FLOOD GUIDANCE WAS DOWN TO ABOUT 1.0 INCH OVER SOME COUNTIES WHERE RECENT RAINFALL OF SEVERAL INCHES HAS OCCURRED. IT LOOKS TO BE HARD FOR STORMS TO PRODUCE SEVERE WEATHER LATER TODAY OR TONIGHT GIVEN A VERY HIGH WET BULB ZERO OVER 13K AND LOW BULK SHEAR WITH STABLE MID LEVEL LAPSE RATES. CURRENT THINKING WIND GUSTS SHOULD TOP OUT AROUND 40 MPH. SOME LINGERING STORMS ARE POSSIBLE WEDNESDAY...BUT GIVEN OVERNIGHT CONVECTION... LOW LEVEL CONDITIONS SHOULD BECOME TOO STABLE TO SUPPORT SEVERE STORMS. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 SHRTWV MOVG INTO THE NRN PLAINS THIS AFTN EXPECTED TO BE LOCATED OVER THE GRTLKS/OH VALLEY WED EVE. ACCOMPANYING SFC CDFNT SHOULD BE JUST SE OF SERN PORTION OF CWA. A SLIGHT CHC OF SHOWERS/TSTMS LINGERING INTO WED EVE WAS MAINTAINED OVER EXTREME SE. CAA/SUBSIDENCE BEHIND THIS SYSTEM WILL RESULT IN DIMINISHING CLOUD COVER WITH COOLER AND LESS HUMID CONDITIONS WED NIGHT AND THU. FAIR WX WILL CONT THU NGT-FRI AS SFC HIGH MOVES SLOWLY EAST ACROSS THE GRTLKS. WK WAA EXPECTED OVER THE WEEKEND AS GRTLKS HIGH MOVES EAST ACROSS NEW ENGLAND AND MERGES WITH STRONG WRN ATLANTIC ANTICYCLONE. THIS ALONG WITH UPR LEVEL RIDGE EXPANDING NEWD FROM THE SRN ROCKIES/PLAINS TOWARD THE GRTLKS SHOULD RESULT IN A WARMING TREND AND DRY CONDITIONS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 735 PM EDT TUE JUL 9 2013 DRY AND LARGELY STABLE CONDITIONS ARE CURRENTLY IN PLACE ACROSS THE LOCAL AREA THANKS TO EARLIER PASSING CONVECTION. A WEAK COLD FRONT WILL APPROACH THE AREA BY LATER TONIGHT AND ASSOCIATED CONVERGENCE COUPLED WITH LINGERING ELEVATED INSTABILITY MAY GENERATE A FEW MORE SHOWERS AND THUNDERSTORMS. LATEST HI-RES MODELS SUGGEST THIS ACTIVITY WILL REMAIN FAIRLY SCATTERED THOUGH AND CONFIDENCE IN THUNDERSTORMS IMPACTING THE TERMINALS IS NOT HIGH. VFR CONDITIONS EXPECTED TOMORROW AS A LARGE HIGH PRESSURE SYSTEM ADVECTS COOLER AND DRIER AIR INTO THE REGION. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR OHZ001-002-004- 005-015-016-024-025. LM...NONE. && $$ UPDATE...AGD SYNOPSIS...MURPHY SHORT TERM...SKIPPER LONG TERM...JT AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
654 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 455 PM EDT TUE JUL 9 2013 THUNDERSTORMS TONIGHT AND EARLY WEDNESDAY WILL END OVER MOST AREAS BY EARLY WEDNESDAY NIGHT. LOWS TONIGHT WILL BE MUGGY...IN THE 70S...BUT WILL BE CONSIDERABLY COOLER WEDNESDAY NIGHT. TEMPERATURES WILL RETURN TO A LITTLE ABOVE NORMAL BY THIS WEEKEND AS AN UPPER LEVEL RIDGE BUILDS INTO THE AREA. CONDITIONS WILL REMAIN DRY AFTER THE STORMS END EARLY WEDNESDAY NIGHT. && .UPDATE... ISSUED AT 651 PM EDT TUE JUL 9 2013 CONVECTION EARLIER THIS AFTERNOON HAS HELPED STABILIZE THE NORTHERN HALF OF OUR CWA...WHILE MLCAPES STILL HOVER AROUND 2000 J/KG IN OUR EXTREME SOUTH. A FEW STRONG STORMS REMAIN POSSIBLE IN THIS AREA BUT FORCING IS WEAK AND DEEP LAYER SHEAR IS ONLY AROUND 20 KTS SO CONVECTION WILL REMAIN ISOLATED AND PULSEY THROUGH THE REST OF THE EVENING. LATEST WATER VAPOR LOOP AND MSAS ANALYSIS SHOW MAIN MIDLEVEL HEIGHT FALLS AND ASSOCIATED COLD FRONT REMAIN WELL NORTHWEST OF HERE. THERE IS ALSO A WEAK AREA OF SUBSIDENCE AND SOME MIDLEVEL DRY AIR AHEAD OF THIS COLD FRONT THAT IS HELPING TO SUPPRESS CONVECTION ACROSS IOWA DESPITE DECENT INSTABILITY. A FEW STORMS HAVE FIRED ACROSS WISCONSIN BUT THE PROSPECTS FOR AN ORGANIZED MCS TO DEVELOP AND PROPAGATE INTO OUR AREA AS SUGGESTED BY SOME EARLIER HI-RES RUNS APPEAR TO BE DWINDLING. LLJ WILL BEGIN TO RAMP UP LATER TONIGHT THOUGH AND THIS ENHANCED CONVERGENCE AHEAD OF THE APPROACHING COLD FRONT WILL HELP SUPPORT SOME PRECIP LATER TONIGHT WITH ABOUT 1000 J/KG OF ELEVATED INSTABILITY. WILL TAKE SOME TIME FOR THIS ACTIVITY TO REACH OUR CWA...PROBABLY AFTER MIDNIGHT...AND THE LATEST HRRR KEEPS CONVECTION FAIRLY SCATTERED. GIVEN POOR MIDLEVEL LAPSE RATES...WEAK FORCING...AND LACK OF CONVECTION/STABLE CONDITIONS IMMEDIATELY UPSTREAM WILL BE ADDING SOME DETAIL TO THE POP GRIDS FOR THIS EVENING AND SCALING BACK TO SCT/CHANCE WORDING FOR THE ENTIRE OVERNIGHT PERIOD. WIDESPREAD SEVERE WEATHER NOT EXPECTED DUE TO ELEVATED NATURE OF STORMS...MARGINAL MUCAPE VALUES...AND WEAK SHEAR. WILL LEAVE THE FLASH FLOOD WATCH UP THOUGH AS ANY SUSTAINED UPDRAFTS/TRAINING STORMS COULD PRODUCE A LOCALIZED FLOODING THREAT WITH SUCH A MOIST AIRMASS IN PLACE...PWATS STILL HOVERING AROUND 2 INCHES. UPDATED ZFP WILL BE OUT SOON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 THUNDERSTORMS WERE CONTINUING TO DEVELOP IN A VERY UNSTABLE AIRMASS AHEAD OF AN APPROACHING UPPER LEVEL TROF AND COLD FRONT. SPC MESO ANALYSIS SHOWS PRECIP WATER VALUES EXCEEDING 2.2 INCHES OVER NRN INDIANA. HOWEVER...MID LEVEL LAPSE RATES OF 5.5 C/KM WERE REALLY LIMITING CONVECTIVE EXTENT UPSTREAM AND MAY BE A SIGNIFICANT FACTOR TONIGHT IN THE DEVELOPMENT OF MORE CONVECTION. FOR THIS PACKAGE... FAVORED MAINLY THE HIGH RES WPC MODELS...ESPECIALLY 4KM NAM. HAVE ADDED A FLASH FLOOD WATCH OVER NW OHIO WHERE 3 HOUR FLASH FLOOD GUIDANCE WAS DOWN TO ABOUT 1.0 INCH OVER SOME COUNTIES WHERE RECENT RAINFALL OF SEVERAL INCHES HAS OCCURRED. IT LOOKS TO BE HARD FOR STORMS TO PRODUCE SEVERE WEATHER LATER TODAY OR TONIGHT GIVEN A VERY HIGH WET BULB ZERO OVER 13K AND LOW BULK SHEAR WITH STABLE MID LEVEL LAPSE RATES. CURRENT THINKING WIND GUSTS SHOULD TOP OUT AROUND 40 MPH. SOME LINGERING STORMS ARE POSSIBLE WEDNESDAY...BUT GIVEN OVERNIGHT CONVECTION... LOW LEVEL CONDITIONS SHOULD BECOME TOO STABLE TO SUPPORT SEVERE STORMS. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 SHRTWV MOVG INTO THE NRN PLAINS THIS AFTN EXPECTED TO BE LOCATED OVER THE GRTLKS/OH VALLEY WED EVE. ACCOMPANYING SFC CDFNT SHOULD BE JUST SE OF SERN PORTION OF CWA. A SLIGHT CHC OF SHOWERS/TSTMS LINGERING INTO WED EVE WAS MAINTAINED OVER EXTREME SE. CAA/SUBSIDENCE BEHIND THIS SYSTEM WILL RESULT IN DIMINISHING CLOUD COVER WITH COOLER AND LESS HUMID CONDITIONS WED NIGHT AND THU. FAIR WX WILL CONT THU NGT-FRI AS SFC HIGH MOVES SLOWLY EAST ACROSS THE GRTLKS. WK WAA EXPECTED OVER THE WEEKEND AS GRTLKS HIGH MOVES EAST ACROSS NEW ENGLAND AND MERGES WITH STRONG WRN ATLANTIC ANTICYCLONE. THIS ALONG WITH UPR LEVEL RIDGE EXPANDING NEWD FROM THE SRN ROCKIES/PLAINS TOWARD THE GRTLKS SHOULD RESULT IN A WARMING TREND AND DRY CONDITIONS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 236 PM EDT TUE JUL 9 2013 THUNDERSTORMS WERE INCREASING IN COVERAGE EARLY THIS AFTERNOON AHEAD OF A COOL FRONT WHERE THE AIRMASS HAS BECOME UNSTABLE. SFC BASED CAPES WERE APPROACHING 3500 J/KG OVR NRN IND...ALTHOUGH WEAK SHEAR AND LIMITED MID LEVEL LAPSE RATES WILL LIMIT STORM SEVERITY. MORE STORMS ARE EXPECTED TONIGHT AHEAD OF AN UPPER LEVEL SYSTEM AND SFC FRONT...SO HAVE INCLUDED A TEMPO GROUP AT BOTH SBN AND FWA. WINDS SHOULD SHIFT TO THE NORTHWEST LATE IN THE PERIOD BEHIND THE FRONT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR OHZ001-002-004- 005-015-016-024-025. LM...NONE. && $$ UPDATE...AGD SYNOPSIS...MURPHY SHORT TERM...SKIPPER LONG TERM...JT AVIATION...SKIPPER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
652 PM EDT MON JUL 8 2013 .SYNOPSIS... ISSUED AT 651 PM EDT MON JUL 8 2013 SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS TONIGHT WITH LOW TEMPERATURES IN THE LOW 70S. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN ON TUESDAY WITH HIGH TEMPERATURES IN THE UPPER 80S. A FEW OF THE THUNDERSTORMS COULD BE STRONG TO SEVERE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 COMPLICATED FCST PERIOD WRT CONVECTIVE POTENTIAL THIS EVENING AND AGAIN ON TUESDAY. AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED THIS MORNING ACROSS NE IL HAVE ADVECTED INTO THE NW CWA THIS AFTERNOON. THIS AREA OF SHOWERS APPEARS TO BE IN A DECAYING STATE...AND HAS WORKED OVER THE ENVIRONMENT ACROSS MUCH OF THE AREA. THE DEGREE OF RECOVERY LATE THIS AFTERNOON AND EARLY THIS EVENING WILL BE CRITICAL TO ANY CONVECTIVE POTENTIAL GOING FORWARD INTO THE OVERNIGHT. HI RES MODELS HAVE DONE A POOR JOB WITH THE CONVECTIVE EVOLUTION OVER THE PAST 6 HOURS. HRRR AND 12Z SPC 4KM RUNS HAVE INDICATED A W-E ORIENTED LINE OF CONVECTION DEVELOPING ACROSS THE LOWER GREAT LAKES REGION AND SINKING SOUTHWARD ACROSS THE AREA...COINCIDENT WITH SHORTWAVE ENERGY ADVECTING SOUTHEAST ACROSS THE LOWER GREAT LAKES PER W/V. THE COVERAGE AND EXTENT OF THIS POTENTIAL CONVECTION WILL BE HIGHLY DEPENDENT ON ATMOSPHERIC RECOVERY. RECENT RAP13 RUNS DO INDICATED A STRONG LOW LVL THETA E POOLING ACROSS NRN IL...ADVECTING INTO NRN IN THROUGH 00Z. THIS OPTIMISTIC SCENARIO WOULD ALLOW MLCAPES TO RECOVER TO 1000-2000 J/KG. MODEST 0-6 KM BULK SHEAR VALUES OF 25-30 KTS...AND 850-500 MB LAPSE RATES OF 5.5-6 C/KM WILL KEEP SEVERE POTENTIAL LOW TO MARGINAL AT THIS POINT....HOWEVER AN ISOLATED STORM PRODUCING STRONG TO SEVERE WIND GUSTS IS POSSIBLE. GIVEN ALL OF THESE FACTORS...DECIDED TO LEAVE POPS IN THE SCATTERED CATEGORY TONIGHT...WITH THE BEST POTENTIAL FOR CONVECTION BETWEEN 22Z AND 04Z. CONVECTIVE OUTFLOW SHOULD PUSH PRECIP POTENTIAL SOUTHWARD THROUGH THE OVERNIGHT HOURS...AND HAVE CONFINED SLIGHT CHANCE POPS TO THE SOUTH. WARM AND MUGGY CONDITIONS ARE EXPECTED AGAIN ON TUESDAY WITH HIGHS TOPPING OUT IN THE MID TO UPPER 80S...WITH HEAT INDICES IN THE LOW TO MID 90S. REMNANT CONVECTIVE BOUNDARY MAY BE A FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY TOMORROW WITH A JUICED ENVIRONMENT. UPSTREAM SHORTWAVE EXPECTED TO ADVECT INTO THE REGION LATE TUESDAY AFTERNOON...WHICH WILL PROVIDE MORE SUPPORT FOR CONVECTION. GIVEN UNCERTAINTY WITH EVOLUTION OF CONVECTION THIS EVENING...AND RESULTING BOUNDARY LOCATION...AS WELL AS UNCERTAINTY WITH THE EVOLUTION OF CONVECTIVELY INDUCED SHORTWAVE...HAVE OPTED TO KEEP POPS IN THE CHANCE RANGE...WITH THE HIGHEST IN THE AFTERNOON. POTENTIAL FOR SEVERE WIND GUSTS TOMORROW DOES EXIST GIVEN HIGHLY UNSTABLE ENVIRONMENT...BUT MODEST BULK SHEAR VALUES OF 25-30 KTS MAY BE A LIMITING FACTOR FOR STORM ORGANIZATION. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 SHARPENING MID LVL TROUGH SWEEPING THROUGH SRN CANADA SHRT TERM WILL PROPEL A VIGOROUS CDFNT THROUGH CWA ON WED. IN LIGHT OF DISPARATE MODEL GUIDANCE WILL GENERALLY RELAY ON HIGHRES CONSENSUS OF FASTER FROPA ESP WITHIN GUISE OF TUE NIGHT CONVN/MCS AND LIKELY OUTFLW REMNANT COMPOSITING MORE EFFECTIVE DY3 FORCING MECHANISM SWD TWD THE OH VALLEY. AS SUCH HAVE SHARPLY CURTAILED POPS ON WED. AFT THAT...HIGH PRES TO RIDGE SWD ACRS THE LAKES AS MID LVL TROUGH AMPLIFIES THROUGH NEW ENGLAND BRINGING SEASONABLE TEMPS TO THE REGION AND DRY WX. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 114 PM EDT MON JUL 8 2013 COMPLICATED TAF FCST GIVEN ONGOING CONVECTIVE ACTIVITY ACROSS THE REGION...AND MODEL GUIDANCE PROVIDING LITTLE INSIGHT ATTM. REMNANTS OF CONVECTION HAVE DEVOLVED INTO LITTLE MORE THAN SPRINKLES ACROSS MUCH OF THE AREA...WITH RENEWED CONVECTION SOUTH OF KORD AND KMDW TO KVPZ. THIS WILL BRING RAIN SHOWER ACTIVITY TO KSBN...BUT CONDITIONS WILL LIKELY REMAIN VFR. MODELS HINTING AT CONVECTION FIRING ACROSS SRN LWR MI AND NRN IN BY 22Z AND SINKING SOUTHWARD ACROSS TAF SITES THROUGH 04Z TIMEFRAME. LITTLE CONFIDENCE IN EXACT EVOLUTION RESULTING IN ONLY VCSH MENTION AT KFWA...HOWEVER MORE CONFIDENT THAT CONVECTION WILL IMPACT KSBN FROM 22Z TO 02Z TIMEFRAME. WILL CONTINUE TO MONITOR CONVECTIVE TRENDS THROUGH THE AFTERNOON AND AMMEND AS NEEDED. ADDED HIGH END MVFR CONDS NEAR DAYBREAK TUESDAY GIVEN GUIDANCE TRENDS...HOWEVER AS MENTION BEFORE WELL MIXED BOUNDARY LAYER SHOULD LIMIT ANY LOW END MVFR/IFR CONDS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...BENTLEY SHORT TERM...NG LONG TERM...T AVIATION...NG VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
315 PM EDT MON JUL 8 2013 .SYNOPSIS... ISSUED AT 1049 AM EDT MON JUL 8 2013 WARMER AND MORE UNSTABLE AIR ACROSS THE REGION WILL LIKELY PROVIDE FOR RENEWED SCATTERED AFTERNOON AND EVENING THUNDERSTORMS TODAY AS AN UPPER LEVEL WAVE ACROSS THE UPPER MISSISSIPPI VALLEY SHIFTS INTO THE SOUTHERN GREAT LAKES. AFTERNOON HIGH TEMPERATURES WILL BE A FEW DEGREES WARMER THAN YESTERDAY...WELL INTO THE MID 80S. MUGGY CONDITIONS COULD MAKE IT FEEL LIKE THE LOWER 90S. RAIN CHANCES WILL DIMINISH OVERNIGHT...AS LOW TEMPERATURES ONLY FALL INTO THE UPPER 60S AND LOW 70S. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 COMPLICATED FCST PERIOD WRT CONVECTIVE POTENTIAL THIS EVENING AND AGAIN ON TUESDAY. AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED THIS MORNING ACROSS NE IL HAVE ADVECTED INTO THE NW CWA THIS AFTERNOON. THIS AREA OF SHOWERS APPEARS TO BE IN A DECAYING STATE...AND HAS WORKED OVER THE ENVIRONMENT ACROSS MUCH OF THE AREA. THE DEGREE OF RECOVERY LATE THIS AFTERNOON AND EARLY THIS EVENING WILL BE CRITICAL TO ANY CONVECTIVE POTENTIAL GOING FORWARD INTO THE OVERNIGHT. HI RES MODELS HAVE DONE A POOR JOB WITH THE CONVECTIVE EVOLUTION OVER THE PAST 6 HOURS. HRRR AND 12Z SPC 4KM RUNS HAVE INDICATED A W-E ORIENTED LINE OF CONVECTION DEVELOPING ACROSS THE LOWER GREAT LAKES REGION AND SINKING SOUTHWARD ACROSS THE AREA...COINCIDENT WITH SHORTWAVE ENERGY ADVECTING SOUTHEAST ACROSS THE LOWER GREAT LAKES PER W/V. THE COVERAGE AND EXTENT OF THIS POTENTIAL CONVECTION WILL BE HIGHLY DEPENDENT ON ATMOSPHERIC RECOVERY. RECENT RAP13 RUNS DO INDICATED A STRONG LOW LVL THETA E POOLING ACROSS NRN IL...ADVECTING INTO NRN IN THROUGH 00Z. THIS OPTIMISTIC SCENARIO WOULD ALLOW MLCAPES TO RECOVER TO 1000-2000 J/KG. MODEST 0-6 KM BULK SHEAR VALUES OF 25-30 KTS...AND 850-500 MB LAPSE RATES OF 5.5-6 C/KM WILL KEEP SEVERE POTENTIAL LOW TO MARGINAL AT THIS POINT....HOWEVER AN ISOLATED STORM PRODUCING STRONG TO SEVERE WIND GUSTS IS POSSIBLE. GIVEN ALL OF THESE FACTORS...DECIDED TO LEAVE POPS IN THE SCATTERED CATEGORY TONIGHT...WITH THE BEST POTENTIAL FOR CONVECTION BETWEEN 22Z AND 04Z. CONVECTIVE OUTFLOW SHOULD PUSH PRECIP POTENTIAL SOUTHWARD THROUGH THE OVERNIGHT HOURS...AND HAVE CONFINED SLIGHT CHANCE POPS TO THE SOUTH. WARM AND MUGGY CONDITIONS ARE EXPECTED AGAIN ON TUESDAY WITH HIGHS TOPPING OUT IN THE MID TO UPPER 80S...WITH HEAT INDICES IN THE LOW TO MID 90S. REMNANT CONVECTIVE BOUNDARY MAY BE A FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY TOMORROW WITH A JUICED ENVIRONMENT. UPSTREAM SHORTWAVE EXPECTED TO ADVECT INTO THE REGION LATE TUESDAY AFTERNOON...WHICH WILL PROVIDE MORE SUPPORT FOR CONVECTION. GIVEN UNCERTAINTY WITH EVOLUTION OF CONVECTION THIS EVENING...AND RESULTING BOUNDARY LOCATION...AS WELL AS UNCERTAINTY WITH THE EVOLUTION OF CONVECTIVELY INDUCED SHORTWAVE...HAVE OPTED TO KEEP POPS IN THE CHANCE RANGE...WITH THE HIGHEST IN THE AFTERNOON. POTENTIAL FOR SEVERE WIND GUSTS TOMORROW DOES EXIST GIVEN HIGHLY UNSTABLE ENVIRONMENT...BUT MODEST BULK SHEAR VALUES OF 25-30 KTS MAY BE A LIMITING FACTOR FOR STORM ORGANIZATION. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 SHARPENING MID LVL TROUGH SWEEPING THROUGH SRN CANADA SHRT TERM WILL PROPEL A VIGOROUS CDFNT THROUGH CWA ON WED. IN LIGHT OF DISPARATE MODEL GUIDANCE WILL GENERALLY RELAY ON HIGHRES CONSENSUS OF FASTER FROPA ESP WITHIN GUISE OF TUE NIGHT CONVN/MCS AND LIKELY OUTFLW REMNANT COMPOSITING MORE EFFECTIVE DY3 FORCING MECHANISM SWD TWD THE OH VALLEY. AS SUCH HAVE SHARPLY CURTAILED POPS ON WED. AFT THAT...HIGH PRES TO RIDGE SWD ACRS THE LAKES AS MID LVL TROUGH AMPLIFIES THROUGH NEW ENGLAND BRINGING SEASONABLE TEMPS TO THE REGION AND DRY WX. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 114 PM EDT MON JUL 8 2013 COMPLICATED TAF FCST GIVEN ONGOING CONVECTIVE ACTIVITY ACROSS THE REGION...AND MODEL GUIDANCE PROVIDING LITTLE INSIGHT ATTM. REMNANTS OF CONVECTION HAVE DEVOLVED INTO LITTLE MORE THAN SPRINKLES ACROSS MUCH OF THE AREA...WITH RENEWED CONVECTION SOUTH OF KORD AND KMDW TO KVPZ. THIS WILL BRING RAIN SHOWER ACTIVITY TO KSBN...BUT CONDITIONS WILL LIKELY REMAIN VFR. MODELS HINTING AT CONVECTION FIRING ACROSS SRN LWR MI AND NRN IN BY 22Z AND SINKING SOUTHWARD ACROSS TAF SITES THROUGH 04Z TIMEFRAME. LITTLE CONFIDENCE IN EXACT EVOLUTION RESULTING IN ONLY VCSH MENTION AT KFWA...HOWEVER MORE CONFIDENT THAT CONVECTION WILL IMPACT KSBN FROM 22Z TO 02Z TIMEFRAME. WILL CONTINUE TO MONITOR CONVECTIVE TRENDS THROUGH THE AFTERNOON AND AMMEND AS NEEDED. ADDED HIGH END MVFR CONDS NEAR DAYBREAK TUESDAY GIVEN GUIDANCE TRENDS...HOWEVER AS MENTION BEFORE WELL MIXED BOUNDARY LAYER SHOULD LIMIT ANY LOW END MVFR/IFR CONDS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MURPHY/KG SHORT TERM...NG LONG TERM...T AVIATION...NG VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
626 PM MDT TUE JUL 9 2013 .UPDATE... ISSUED AT 623 PM MDT TUE JUL 9 2013 FORECAST HAS BEEN UPDATED FOR THE EXPIRATION OF THE HEAT ADVISORY AND ISSUANCE OF SEVERE THUNDERSTORM WATCH 405. STORMS SHOULD SLOWLY MOVE OUT OF THE FORECAST AREA THIS EVENING. RECENT RUNS OF THE HRRR MODEL SUGGEST THAT STORMS CURRENTLY IN NORTHWEST NEBRASKA MAY MOVE TO THE SOUTHEAST ALONG THE EDGE OF THE RIDGE OF HIGH PRESSURE. THESE STORMS WOULD MOVE INTO SOUTHWEST NEBRASKA AND PORTIONS OF NORTHWEST KANSAS LATE TONIGHT. CAN NOT RULE OUT THESE STORMS CLIPPING NORTHEAST COLORADO AS WELL. WILL CONTINUE TO WATCH THESE STORMS AS WELL AND UPDATE AS NEEDED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 143 PM MDT TUE JUL 9 2013 A HEAT ADVISORY REMAINS IN EFFECT FOR A PORTION OF THE FORECAST AREA THIS AFTERNOON AS AMBIENT TEMPERATURES AND HEAT INDEX VALUES INCREASE INTO THE 103-107 DEGREE RANGE. ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND EVENING IN THE UNSTABLE AND CONVERGENT NEAR SURFACE REGION IN THE VICINITY OF A SURFACE TROUGH THAT EXTENDS FROM WEST CENTRAL KANSAS THROUGH SOUTHEAST NEBRASKA. STORM DEVELOPMENT WILL BE AIDED BY THE LIFT ASSOCIATED WITH THE TAIL END OF THE UPPER TROUGH WILL CONTINUE TO MOVE EASTWARD OVER THE NORTHERN PLAINS THIS EVENING. SOME STORMS MAY BECOME SEVERE WITH THE STRONGER STORMS EXPECTED MAINLY ALONG THE SOUTHEAST BORDER OF THE FORECAST AREA. THE COLD FRONT POISED NORTH OF THE FORECAST AREA WILL PUSH SOUTHWARD OVERNIGHT TONIGHT AND DURING THE DAY ON WEDNESDAY. HIGH TEMPERATURES WILL BE ABOUT 10 DEGREES COOLER ON WEDNESDAY THAN ON TUESDAY...BUT ARE EXPECTED TO REACH MAINLY INTO THE LOWER TO MID 90S. THE FRONTAL BOUNDARY ENDS UP OVER THE SOUTHERN AND WESTERN SECTIONS OF THE FORECAST AREA LATE IN THE DAY ON WEDNESDAY AS SURFACE HIGH PRESSURE MOVES INTO PLACE OVER THE PLAINS STATES. SCATTERED THUNDERSTORMS...SOME BECOMING SEVERE...ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN TO THE WEST ALONG THE FRONTAL BOUNDARY ON WEDNESDAY AFTERNOON AND EVENING. STORMS WILL DECREASE IN COVERAGE AND INTENSITY AS THEY MOVE ACROSS THE REMAINDER OF THE FORECAST AREA DURING THE EVENING AND OVERNIGHT HOURS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 232 PM MDT TUE JUL 9 2013 WED NIGHT-FRIDAY...591 DM H5 RIDGE WILL BE MAIN SYNOPTIC SCALE INFLUENCE ON THE CWA THROUGH THE PERIOD AS IT BEGINS TO BUILD INTO THE AREA ON WED NIGHT BEFORE BECOMING CENTERED OVER THE CWA ON THURSDAY. SHORT WAVE TROUGH NOTED ON PROJECTED DYNAMIC TROPOPAUSE FIELDS WILL AID IN THE DEVELOPMENT OF AFTERNOON AND EVENING THUNDERSTORMS AS LARGE SCALE EASTERLY FLOW WILL KEEP AXIS OF INSTABILITY CENTERED OVER THE AREA. GIVEN EXPECTED FLOW PATTERN...STORMS SHOULD DRIFT TO THE SOUTHEAST INTO INCREASING INSTABILITY AND THINK POTENTIAL FOR PRECIPITATION EXISTS ACROSS THE ENTIRE CWA. FAIRLY CONFIDENT THAT STORMS WILL DEVELOP...BUT WITH MODELS VARYING GREATLY BETWEEN EARLY AFTERNOON INITIATION/ENDING AND PRECIPITATION MAINLY OCCURRING IN THE EVENING CONFIDENCE IN TIMING TOO LOW TO GO ABOVE THE CHANCE RANGE. GIVEN EXPECTED THERMAL AND WIND FIELDS...STRONG WAA MAY ALLOW STORMS TO LINGER THROUGH THE NIGHT ESPECIALLY IN THE EASTERN CWA. PRECIPITATION CHANCES WILL DIMINISH THROUGH THE REST OF THE PERIOD AS LARGE SCALE RIDGE MOVES OVER THE AREA BRINGING WIDESPREAD SUBSIDENCE AND INCREASED CINH. A STORM OR TWO IS POSSIBLE...BUT THINK COVERAGE WILL BE VERY LIMITED. FOR TEMPS...POTENTIAL FOR OUTFLOW FROM WED NIGHT CONVECTION LOWERS CONFIDENCE IN TEMP FORECAST ALTHOUGH GIVEN MODEL BIASES THE PAST 2 WEEKS NOT SURE IF I WANT TO GO AS COOL AS OPERATIONAL DATA SUGGESTS. ANY POSSIBLE COOL DOWN WILL BE SHORT LIVED AS TEMPERATURES REBOUND INTO THE LOW 100S BY FRIDAY. IN THE EXTENDED (FRI NIGHT-TUESDAY)...STRONG H5 RIDGE WILL CONTINUE TO DOMINATE THE WEATHER PATTERN THROUGH THE PERIOD...ALTHOUGH THERE DOES APPEAR TO BE POTENTIAL FOR SFC FRONT STALLING NEAR THE AREA BRINGING THE CHANCE FOR THUNDERSTORMS. LATEST OPERATIONAL MODELS HAVE BACKED OFF PRECIP THREAT TO SOME DEGREE...FOCUSING WEST AND NORTH OF THE CWA. WAS INCLINED TO BACK OFF POPS 10-15 PERCENT...BUT WITH GEFS STILL INDICATING A FAIRLY ROBUST PRECIP SIGNAL HAVE OPTED TO LET CURRENT CONSENSUS POPS REMAIN AS IS FOR THE TIME BEING. OTHERWISE...WARM TEMPERATURES IN THE 90S TO LOW 100S WILL CONTINUE THROUGH THE PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 519 PM MDT TUE JUL 9 2013 AFTERNOON THUNDERSTORMS HAVE MOVED AWAY FROM KGLD AND SHOULD AVOID KMCK BEFORE DIMINISHING. WINDS AT KGLD WILL VARY OVER THE NEXT 2-3 HOURS AS THUNDERSTORM OUTFLOWS MOVE THROUGH. NORTHEAST WINDS SHOULD RESUME ONCE OUTFLOW BOUNDARIES BEGIN TO WEAKEN AND WASH OUT. SREF GUIDANCE IS SUGGESTING A CHANCE OF SOME LOW STRATUS AT KGLD TONIGHT BUT THE OCCURRENCE DOES NOT SEEM LIKELY. WINDS WILL BECOME EASTERLY BY TOMORROW MORNING WITH STRONGER SOUTHEAST WINDS EXPECTED LATER. THUNDERSTORMS SHOULD DEVELOP ALONG THE FRONT AND REMAINING OUTFLOW BOUNDARIES TOMORROW...MOST LIKELY IMPACTING KGLD IN THE LATE AFTERNOON TO EVENING HOURS. WILL HOLD OFF ON MENTIONING TS BUT A MENTION WILL LIKELY BE NEEDED IN LATER TAFS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...RRH SHORT TERM...LOCKHART LONG TERM...JRM AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
622 PM CDT TUE JUL 9 2013 ...UPDATED FOR THE 00Z TAF AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 300 PM CDT TUE JUL 9 2013 ON THE SYNOPTIC SCALE, A MUCH MORE ZONAL FLOW HAS DEVELOPED ACROSS THE CONUS WITH A POLAR JET FOCUSES ACROSS THE NORTHERN STATES, AND A BROAD MID LEVEL SHORTWAVE EMBEDDED IN THE FLOW ACROSS EASTERN MONTANA. TEMPERATURES WARMED INTO THE UPPER 80S TO AROUND 90 DEGREES BY 11 AM ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS. TEMPERATURES WERE SLIGHTLY SLOWER TO RESPOND ACROSS SECTIONS OF WEST CENTRAL KANSAS WHERE BANDS OF MID LEVEL STRATOCUMULUS WERE PRESENT. THIS PATTERN INCLUDES A FLATTENING OF THE UPPER ANTICYCLONE NOW LOCATED FROM THE DESERT SOUTHWEST INTO THE SOUTHERN PLAINS. THE 12 UTC 700 MB ANALYSIS SHOWED A WARM PLUME OF MID LEVEL AIR ACROSS EASTERN COLORADO AND WESTERN KANSAS AS WARM AS 15 DEGREES C. THE 850 MB LEVEL TROUGH WHICH EXTENDED ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS CREATED A DOWNSLOPE SURFACE WIND FIELD OVER SOUTHWEST AND CENTRAL KANSAS WITH TEMPERATURES IN THE UPPER 20`S C. AT THE SURFACE, A BETTER IDENTIFIED COLD FRONT BASED ON SURFACE MOISTURE DISCONTINUITY EXTENDED ACROSS WESTERN NEBRASKA THROUGH THE EASTERN DAKOTAS, WHILE AN AREA OF LOW PRESSURE AHEAD OF THE BOUNDARY EXHIBITED ANS ATTENDANT TROUGH FROM CENTRAL NEBRASKA INTO WEST CENTRAL KANSAS. JUST AHEAD OF THE SURFACE TROUGH, DEW POINTS OF 60 TO 65 DEGREES CONTRIBUTED TO PRECIPITABLE WATER VALUES IN EXCESS OF AN INCH AND A HALF THROUGH THE INTERSTATE 70 AND HIGHWAY 156 CORRIDORS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 300 PM CDT TUE JUL 9 2013 THE HEAT AND CONVECTIVE CHANCES INCLUDING POTENTIAL IMPACTS ARE THE MAIN FORECAST ISSUES EARLY IN THE SHORT TERM. THE HEAT ADVISORY WILL BE MAINTAINED IN IT`S CURRENT CONFIGURATION ALTHOUGH THE WESTERN PERIPHERY MAY BE SUSPECT TO MEETING LOW END ADVISORY CRITERIA DUE TO SURFACE DEW POINTS THAT HAVE MIXED OUT INTO THE MID/UPPER 50`S. IF THE TREND CONTINUES INTO EARLY AFTERNOON, IN EFFECT TEMPERATURES ALSO ARE NOT TRENDING AS WARM AS FORECAST, SOME AREAS ALONG THE WESTERN PERIPHERY MAY NEED TO BE TRIMMED FROM THE ADVISORY. THE NAM/ WRF NMM AND ARW ALL DEVELOP CONVECTION ALONG THE FRONTAL BOUNDARY EXTENDING INTO NORTHWEST KANSAS THIS AFTERNOON. SIGNIFICANT DIFFERENCES IN COVERAGE EXISTS BETWEEN THE MODELS, VARYING FROM RATHER ISOLATED CLUSTERS TO MORE ORGANIZED LINE SEGMENTS WITH PROLIFIC OUTFLOW. THE HRRR IS PARTICULARLY AGGRESSIVE WITH DEVELOPING HEAVY QPF AND RAIN COOLED OUTFLOW OF 30 KNOTS LOCALLY RIGHT AHEAD OF THE FRONT ALONG THE MAXIMUM DEW POINT AND PWAT GRADIENT. HOWEVER THE WEATHER EVOLVES THIS AFTERNOON AND EVENING MAY HAVE AN IMPACT ON TEMPERATURES AND CONVECTIVE CHANCES AGAIN ON WEDNESDAY AFTERNOON. HOWEVER, THE BETTER CHANCE FOR CONVECTION ON WEDNESDAY WILL LIKELY OCCUR DUE TO DIFFERENTIAL HEATING OVER THE HIGHER TERRAIN OF EASTERN COLORADO, INCREASING CHANCES ACROSS WESTERN KANSAS INTO WEDNESDAY EVENING. HIGHS WEDNESDAY WILL BE AROUND 10 DEGREES COOLER BEHIND THE BOUNDARY. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 215 PM CDT TUE JUL 9 2013 A WARM AND FAIRLY DRY PERIOD BEGINS AFTER WEDNESDAY NIGHT AS A LARGE RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS INTO THE PLAINS. FOR WEDNESDAY NIGHT WILL MAINTAIN A 30 TO 40 PERCENT CHANCE OF THUNDERSTORMS JUST NORTH OF A WEAK FRONTAL BOUNDARY IN MOIST UPSLOPE REGIME ACROSS MUCH OF WESTERN KANSAS. THIS WILL BE OUR BEST CHANCE OF SEEING MEASURABLE RAINFALL INTO NEXT WEEK. WITH WEAK WINDS ALOFT NOT EXPECTING SEVERE WEATHER. THERE COULD BE SOME LOCALLY HEAVY DOWNPOURS IF STORMS GET GOING AND THEY ARE SLOW MOVING. A WESTWARD MOVING UPPER LOW BEGINS TO UNDERCUT THE RIDGE ACROSS THE SOUTHERN AND CENTRAL PLAINS FROM SUNDAY INTO TUESDAY WITH A SLIGHT CHANCE OF THUNDERSTORMS ON MONDAY NEAR A CONVERGENCE LINE, ALONG WITH SLIGHTLY COOLER TEMPERATURES. OVERNIGHT LOWS WILL BE MILD AROUND 70 TO 75 THROUGH THE PERIOD. DAYTIME HIGHS WARM BACK TO AROUND 100 TO 105 ON FRIDAY AND SATURDAY THEN COOL SLIGHTLY BACK INTO THE MID TO UPPER 90S INTO NEXT TUESDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 615 PM CDT TUE JUL 9 2013 AS AN UPPER LEVEL WAVE CROSSED EAST ACROSS WESTERN KANSAS, AND A WEAK COLD FRONT CROSSES TO THE SOUTHEAST EARLY TONIGHT, SCATTERED STRONG STORMS ARE POSSIBLE AT KHYS AND KDDC TAF SITES. HOWEVER, AT THIS WRITING, KGCK SEEMS OUT OF THE PATH OF ANY STORMS. WITH THIS STATED, MOST ANY THUNDERSTORM WILL BE ELEVATED, AND THUS VFR CONDITIONS ARE EXPECTED THROUGH THE 24 HOUR TAF PERIOD. THE EXCEPTIONS WILL BE AT KHYS, WHERE LOW LEVEL MOISTURE FROM PREVIOUS STORMS HAS FORMED INTO SOME 3SM BR. IT THINK AFTER THE CURRENT WAVE OF STORMS PASS, THE VSBY AT KHYS WILL IMPROVE BY 02Z. WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT, AND CIGS WILL GENERALLY BE IN THE BKN080-100 RANGE. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 97 70 98 / 60 30 30 10 GCK 71 95 69 99 / 60 30 30 10 EHA 71 96 69 101 / 40 30 30 10 LBL 72 98 70 102 / 40 30 30 10 HYS 72 94 69 95 / 60 20 20 20 P28 76 100 72 97 / 50 20 20 20 && .DDC WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ030-031-044>046- 064>066-078>081-088>090. && $$ SYNOPSIS...RUSSELL SHORT TERM...RUSSELL LONG TERM...KRUSE AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
234 AM MDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1254 PM MDT SUN JUL 7 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOW H5 RIDGE STILL IN PLACE ACROSS SOUTHERN PLAINS WITH SERIES OF WEAK SHORTWAVE TROUGHS ROTATING AROUND WESTERN AND NORTHERN EXTENT OF RIDGE THROUGH WESTERLY FLOW. AT THE SURFACE A COLD FRONT HAS STALLED ALONG THE KS/NE BORDER WITH A SURFACE TROUGH EXTENDING SOUTH ALONG THE KS/CO BORDER. A WEAK SHORTWAVE TROUGH EXPECTED TO DROP SOUTH OUT OF WESTERN NEBRASKA LATE THIS AFTERNOON AND TONIGHT WILL COMBINE WITH THESE SURFACE FEATURES TO INITIATE SCATTERED THUNDERSTORMS ACROSS THE CWA. PRIMARY FOCUS SHOULD BE ALONG FRONT WHERE HIGH TD VALUES NORTH OF THE FRONT HAVE RESULTED IN ML CAPE 1000-1500 J/KG AS OF THE LATEST RAP ANALYSIS. BETTER DEEP SHEER IS EXPECTED TO BE IN PLACE NORTH OF THE FRONT WHERE 0-6KM BULK SHEER AROUND 35KT BY 00Z COULD SUPPORT A SEVERE WIND AND HAIL THREAT. THERE IS LESS INSTABILITY AND MORE CIN TO OVERCOME FURTHER SOUTH ALONG THE SURFACE TROUGH...HOWEVER AS DAYTIME HEATING CONTINUES AND THE SHORTWAVE TROUGH MOVES SOUTH WE SHOULD BE ABLE TO SEE AT LEAST ISOLATED THUNDERSTORMS DEVELOPING ALONG THE SURFACE TROUGH THIS AFTERNOON/EVENING. PWAT VALUES 1.2-1.3" REPRESENT AN ANOMALOUSLY WET ATMOSPHERE FOR THIS TIME OF YEAR...AND AS WAS THE CASE YESTERDAY MANY OF THESE STORMS WILL BE SLOW MOVERS...SO HEAVY RAIN WILL BE A CONCERN WHERE STORMS DEVELOP. LEE TROUGH IS EXPECTED TO BEGIN TO DEEPEN LATE TONIGHT WITH LLJ BUILDING ACROSS THE NE HALF OF THE CWA. WITH INCREASING ISENTROPIC ASCENT AND H85 SUPPORT WE COULD SEE LINGERING THUNDERSTORMS IN PROXIMITY OF THE FRONTAL ZONE ACROSS OUR NE CWA...SO I KEPT ISO THUNDER MENTION MOST OF THE NIGHT FOR THOSE LOCATIONS. THERE IS SOME INDICATION WITH VERY MOIST E-NE BL FLOW OF FOG DEVELOPING IN SW NEBRASKA...HOWEVER WITH BL LIKELY MIXED WITH LLJ INCREASING AND FRONT POSSIBLY SHIFTING NORTH I WAS NOT CONFIDENT ENOUGH TO ADD MENTION. DESPITE LARGE SCALE FORCING IN PLACE MONDAY IT DOES LOOK LIKE A TROUGH AXIS/DRYLINE ALONG KS/CO BORDER COULD HELP INITIATE THUNDERSTORMS BY THE AFTERNOON WITH INSTABILITY BUILDING ACROSS THE EASTERN CWA. I WASNT CONFIDENT ENOUGH TO ADD MORE THAN SLIGHT CHANCE MENTION AT THIS POINT. H85 TEMPS ARE ACTUALLY ADVERTISED TO BE 2-3C WARMER THAN THE LAST FEW DAYS WHEN HIGHS HAVE BEEN AROUND 100F...SO WE COULD BE LOOKING AT NEAR RECORD HIGH TEMPS ACROSS THE CWA MONDAY WITH VALUES IN THE 100S ACROSS THE AREA. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 232 AM MDT MON JUL 8 2013 STRONG 500 MB HIGH PRESSURE WILL START OVER THE FOUR CORNERS REGION FOR THURSDAY AND WILL SLOWLY PROPAGATE EASTWARD INTO THE HIGH PLAINS REGION FOR FRIDAY AND SATURDAY. RIDGE AXIS WILL TAKE ON A MORE NEGATIVE TILT AS UPPER LEVEL JET STREAM RETURNS TO A MORE ZONAL FLOW FOR THE WEEKEND. THE JET WILL STILL REMAIN WELL TO THE NORTH OF THE TRI STATE AREA...KEEPING WEATHER PATTERN STAGNANT FOR THE DURATION OF THE EXTENDED FORECAST PERIOD. THE UPPER LEVEL RIDGE WILL TAKE A MORE BROAD SHAPE ACROSS THE WESTERN AND CENTRAL PART OF THE CONUS INTO EARLY NEXT WEEK. SURFACE LOW PRESSURE SYSTEM WILL REMAIN OVER THE TRI STATE AREA FOR THE PERIOD WITH CHANCES OF ISOLATED THUNDERSTORMS TO DEVELOP FOR THURSDAY AND FRIDAY. CHANCES INCREASE FOR PRECIPITATION SUNDAY AND EARLY NEXT WEEK AS A POTENTIAL ALBERTA CLIPPER SYSTEM DEVELOPS AND MOVES THROUGH THE HIGH PLAINS. HIGH TEMPERATURES WILL REMAIN WARM INTO THE UPPER 90S AND LOWER 100S FOR THE AREA UNTIL SUNDAY...WHERE TEMPERATURES WILL COOL SLIGHTLY AND APPROACH NEAR NORMAL FOR THE TRI STATE AREA WITH HIGHS IN THE UPPER 80S AND LOWER 90S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1105 PM MDT SUN JUL 7 2013 VFR CONDITIONS EXPECTED AT KGLD AND KMCK. ERRATIC AND POSSIBLY GUSTY WINDS STILL POSSIBLE FROM TAF ISSUANCE THROUGH 08Z AS SHOWERS AND THUNDERSTORMS MOVE ACROSS THE TERMINALS. BETWEEN 08Z- 12Z WINDS SHOULD BECOME SOUTHERLY AT 10KTS OR SO WITH ONLY SOME MID AND HIGH LEVEL CLOUDINESS. DURING THE MID TO LATE AFTERNOON SOUTHERLY WINDS OF 13-15KTS WITH HIGHER GUSTS TO DEVELOP AND CONTINUE THROUGH THE EARLY EVENING HOURS. DIURNAL LATE AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS POSSIBLE ONCE AGAIN FOR BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DJR LONG TERM...MK AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1105 PM MDT SUN JUL 7 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1254 PM MDT SUN JUL 7 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOW H5 RIDGE STILL IN PLACE ACROSS SOUTHERN PLAINS WITH SERIES OF WEAK SHORTWAVE TROUGHS ROTATING AROUND WESTERN AND NORTHERN EXTENT OF RIDGE THROUGH WESTERLY FLOW. AT THE SURFACE A COLD FRONT HAS STALLED ALONG THE KS/NE BORDER WITH A SURFACE TROUGH EXTENDING SOUTH ALONG THE KS/CO BORDER. A WEAK SHORTWAVE TROUGH EXPECTED TO DROP SOUTH OUT OF WESTERN NEBRASKA LATE THIS AFTERNOON AND TONIGHT WILL COMBINE WITH THESE SURFACE FEATURES TO INITIATE SCATTERED THUNDERSTORMS ACROSS THE CWA. PRIMARY FOCUS SHOULD BE ALONG FRONT WHERE HIGH TD VALUES NORTH OF THE FRONT HAVE RESULTED IN ML CAPE 1000-1500 J/KG AS OF THE LATEST RAP ANALYSIS. BETTER DEEP SHEER IS EXPECTED TO BE IN PLACE NORTH OF THE FRONT WHERE 0-6KM BULK SHEER AROUND 35KT BY 00Z COULD SUPPORT A SEVERE WIND AND HAIL THREAT. THERE IS LESS INSTABILITY AND MORE CIN TO OVERCOME FURTHER SOUTH ALONG THE SURFACE TROUGH...HOWEVER AS DAYTIME HEATING CONTINUES AND THE SHORTWAVE TROUGH MOVES SOUTH WE SHOULD BE ABLE TO SEE AT LEAST ISOLATED THUNDERSTORMS DEVELOPING ALONG THE SURFACE TROUGH THIS AFTERNOON/EVENING. PWAT VALUES 1.2-1.3" REPRESENT AN ANOMALOUSLY WET ATMOSPHERE FOR THIS TIME OF YEAR...AND AS WAS THE CASE YESTERDAY MANY OF THESE STORMS WILL BE SLOW MOVERS...SO HEAVY RAIN WILL BE A CONCERN WHERE STORMS DEVELOP. LEE TROUGH IS EXPECTED TO BEGIN TO DEEPEN LATE TONIGHT WITH LLJ BUILDING ACROSS THE NE HALF OF THE CWA. WITH INCREASING ISENTROPIC ASCENT AND H85 SUPPORT WE COULD SEE LINGERING THUNDERSTORMS IN PROXIMITY OF THE FRONTAL ZONE ACROSS OUR NE CWA...SO I KEPT ISO THUNDER MENTION MOST OF THE NIGHT FOR THOSE LOCATIONS. THERE IS SOME INDICATION WITH VERY MOIST E-NE BL FLOW OF FOG DEVELOPING IN SW NEBRASKA...HOWEVER WITH BL LIKELY MIXED WITH LLJ INCREASING AND FRONT POSSIBLY SHIFTING NORTH I WASNT CONFIDENT ENOUGH TO ADD MENTION. DESPITE LARGE SCALE FORCING IN PLACE MONDAY IT DOES LOOK LIKE A TROUGH AXIS/DRYLINE ALONG KS/CO BORDER COULD HELP INITIATE THUNDERSTORMS BY THE AFTERNOON WITH INSTABILITY BUILDING ACROSS THE EASTERN CWA. I WASNT CONFIDENT ENOUGH TO ADD MORE THAN SLIGHT CHANCE MENTION AT THIS POINT. H85 TEMPS ARE ACTUALLY ADVERTISED TO BE 2-3C WARMER THAN THE LAST FEW DAYS WHEN HIGHS HAVE BEEN AROUND 100F...SO WE COULD BE LOOKING AT NEAR RECORD HIGH TEMPS ACROSS THE CWA MONDAY WITH VALUES IN THE 100S ACROSS THE AREA. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 1251 PM MDT SUN JUL 7 2013 AN UPPER RIDGE CENTERED OVER THE SOUTHERN ROCKIES WILL BE THE DOMINATING INFLUENCE THROUGH THE LONG TERM PERIOD. TEMPERATURES WILL BE ABOVE NORMAL...ALTHOUGH A WEAK COLD FRONT ON TUESDAY WILL KNOCK TEMPERATURES DOWN A FEW DEGREES THROUGH THURSDAY...THEY WILL WARM AGAIN FOR THE LATE WEEK AND WEEKEND. POSITION OF THE RIDGE EARLY IN THE PERIOD WILL BE CLOSER TO THE FOUR CORNERS AND ALLOW SHORTWAVE TROUGHS ROTATING AROUND IT TO BRING A CHANCE FOR SCATTERED THUNDERSTORMS. AS THE RIDGE BUILDS EASTWARD LATER IN THE WEEK...THUNDERSTORM CHANCES WILL BECOME MORE ISOLATED. SEVERE WEATHER IS NOT ANTICIPATED WITH THE WEAK FLOW ALOFT LIMITING UPDRAFT ORGANIZATION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1105 PM MDT SUN JUL 7 2013 VFR CONDITIONS EXPECTED AT KGLD AND KMCK. ERRATIC AND POSSIBLY GUSTY WINDS STILL POSSIBLE FROM TAF ISSUANCE THROUGH 08Z AS SHOWERS AND THUNDERSTORMS MOVE ACROSS THE TERMINALS. BETWEEN 08Z- 12Z WINDS SHOULD BECOME SOUTHERLY AT 10KTS OR SO WITH ONLY SOME MID AND HIGH LEVEL CLOUDINESS. DURING THE MID TO LATE AFTERNOON SOUTHERLY WINDS OF 13-15KTS WITH HIGHER GUSTS TO DEVELOP AND CONTINUE THROUGH THE EARLY EVENING HOURS. DIURNAL LATE AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS POSSIBLE ONCE AGAIN FOR BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DJR LONG TERM...024 AVIATION...99
AREA FORECAST DISCUSSION
NWS JACKSON KY
1057 PM EDT TUE JUL 9 2013 .UPDATE... ISSUED AT 1056 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. SPOTTER REPORTS CAME IN FROM MCCREARY COUNTY WITH TREES DOWN AND REPORTS OF FLOODING. THE ONE SPOTTER TOLD US THEY HAVE LIVED IN THE SAME PLACE FOR 44 YEARS...AND THEY NEVER SAW THE WATER RAISE THAT QUICKLY. WITH THE SATURATED GROUND FROM ALL THE RECENT RAINFALL AND THE DEWPOINTS IN THE 70S...LOCALIZED FLASH FLOODING WILL BE A REAL POSSIBILITY AND WILL NEED TO BE MONITORED CLOSELY. THE AREA RIVERS HAVE NOW TEMPORARILY ALL FALLEN BELOW ACTION STAGE. WILL HAVE TO WAIT AND SEE HOW MUCH RAIN WILL FALL OVER THE NEXT 24-36 HOURS. IT WILL NOT TAKE MUCH TO GET THE RIVERS RISING AGAIN. SPC HAS PUT PART OF EASTERN KENTUCKY IN A SLIGHT RISK FROM SEVERE THUNDERSTORMS. FROM LOOKING AT THE NAM BUFR SOUNDINGS...THIS APPEARS TO HAVE A VERY LOW CHANCE TO SEE MORE THAN ONE OR TWO SEVERE REPORTS AS THIS NEXT SYSTEM MOVES THROUGH THE AREA WEDNESDAY NIGHT AND THURSDAY. UPDATE ISSUED AT 755 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE AREA SOUTH AND WEST OF JACKSON GOOD REALLY ACTIVE IN THE LAST FEW HOURS. THE UNSTABLE MOIST AIR WAS REALLY PRIMED...ALL THAT WAS NEEDED WAS THE CONVECTIVE INITIATION. ONE OF THE STORMS GOT REALLY STRONG AND REACHED OUR RADAR BASED SEVERE WEATHER CRITERIA. NO REPORTS HAVE BEEN REPORTED YET. THE MOISTURE LADEN IS CAPABLE OF DUMPING A LOT OF RAIN IN A SHORT TIME. RADAR ESTIMATES OF GREATER THAN TWO INCHES WAS RESPONSIBLE FOR PRODUCING SOME FLASH FLOODING IN THE HOLLY HILL AREA. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 329 PM EDT TUE JUL 9 2013 ISOLD TO SCT SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE AREA THIS AFTERNOON. MORE SUBSTANTIAL AREA OF CONVECTION HAS FIRED OVER OHIO. HRRR HAS ACTUALLY BEEN DOING DECENT WITH CONVECTIVE INITIATION ACROSS AREAS NORTH OF THE OHIO RIVER. IN GENERAL IT KEEPS THE BULK OF ACTIVITY NORTH AND EAST OF OUR CWA...THOUGH RADAR TRENDS WOULD SUGGEST THAT OUR NORTHERN AND EASTERN COUNTIES MAY GET BRUSHED. INCREASED POPS ACROSS THE NORTHERN/EASTERN PORTIONS OF OUR CWA FOR THE LATE AFTERNOON AND EARLY EVENING TIME FRAME. PER THE HRRR...WITH COMPLEX OF STORMS PASSING GENERALLY TO OUR EAST THIS EVENING AND LOSS OF DIURNAL HEATING GRADUALLY DROPPED POPS OFF THROUGH THE NIGHT. HOWEVER...RAMPED POPS BACK UP TOWARDS DAWN AS SHORT TERM HIGH RESOLUTION MODELS SUGGEST THE POSSIBILITY OF THE REMNANTS OF ANOTHER COMPLEX OF STORMS ENTERING THE AREA FROM THE NORTHWEST. OTHERWISE...MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE SHORT TERM. A DEEPENING UPPER LEVEL TROUGH AND REFLECTED SFC COLD FRONT WILL GRADUALLY PUSH THROUGH THE REGION WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. PWATS OVER THE NEXT 36 TO 48 HOURS ARE SIGNIFICANT HITTING CLIMATOLOGICAL HIGHS AT TIMES. FORECAST SOUNDINGS ARE NOT IN AS GOOD AGREEMENT WITH RESPECT TO STORM MOTION THOUGH. THE GFS IS MORE PROGRESSIVE WITH MOVEMENT WHEN COMPARED TO THE HIGHER RESOLUTION RAP AND NAM. REGARDLESS...WITH SUCH HIGH PWATS AND CONSIDERING A FAIRLY SATURATED GROUND FEEL THERE WILL BE THE POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL AND MINOR HYDRO ISSUES...ESPECIALLY WITH THE STRONGER STORMS. CONFIDENCE WAS LACKING WITH RESPECT TO A WIDESPREAD THREAT SO OPTED NOT TO ISSUE ANY TYPE OF FFA. BUT MAY RECONSIDER A FLASH FLOOD WATCH WITH FUTURE FORECAST PACKAGES SHOULD MODELS COME INTO A LITTLE BETTER AGREEMENT WITH RESPECT TO DETAILS...AND SHOW A MORE SIGNIFICANT THREAT. FOR NOW WILL CONTINUE TO COVER THIS POTENTIAL IN THE HWO AND PASS CONCERNS ON TO FUTURE SHIFTS. GENERALLY FOLLOWED INHERITED TEMPS...NUDGING SLIGHTLY TOWARDS A BLEND OF MODEL GUIDANCE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 329 PM EDT TUE JUL 9 2013 THE MODELS HAVE A SIMILAR IDEA...THROUGH THE EXTENDED...OF A MID LEVEL PATTERN DOMINATED BY A LARGE AREA OF RIDGING...INITIALLY OVER THE SOUTHERN ROCKIES EXPANDING NORTHEAST WITH TIME...AND DOWNSTREAM TROUGHING THROUGH THE GREAT LAKES LATER AFFECTING MUCH OF THE EAST AND DEEP SOUTH. THE GREAT LAKES TROUGH STRENGTHENS A BIT ON THURSDAY AS ITS CORE MOVES EAST AND INTO UPSTATE NEW YORK BY 12Z FRIDAY. AT THE SAME TIME...ITS TRAILING AXIS AND MAIN ENERGY BAND WILL SWEEP SOUTHEAST THROUGH THE LOWER OHIO VALLEY AND ACROSS EAST KENTUCKY. THIS WILL ALLOW HEIGHTS TO BUILD IN FROM THE NORTHWEST THROUGH THE WEEKEND WHILE THE SOUTHERN PORTION OF THE TROUGH CUTS OFF OVER THE DEEP SOUTH AND STARTS TO CONSOLIDATE. THOUGH THE MODELS GENERALLY AGREE ON THE RIDGE PLACEMENT...THEY DIFFER ON THE DETAILS REGARDING THE LOWER HEIGHT CENTERS TO THE SOUTH AND EAST. INTO THIS MIX WILL ENTER THE UPPER HEIGHT FIELD OF CHANTAL...OR WHATEVER BECOMES OF HER...THAT COULD MOVE TO THE SOUTHEAST COAST PER THE GEM OR STAY LOCKED OUT TO THE SOUTH AS SEEN IN THE GFS AND ECMWF. EITHER WAY...ITS MOISTURE MAY START TO IMPACT THE AREA AS EARLY AS LATE SUNDAY...LINGERING THROUGH THE REST OF THE EXTENDED. FOR EAST KENTUCKY...THE RIDGE TO THE NORTH WILL BE A KEY COMPONENT IN DETERMINING OUR WEATHER INTO THE START OF NEXT WEEK. WITH THE MODELS IN BETTER AGREEMENT ON THIS FEATURE CONFIDENCE IS HIGHER IN GOING DRY THROUGH AT LEAST MIDDAY SUNDAY. THEREAFTER...THE GFS...AND TO A LESSER EXTENT THE ECMWF...DOES BRING AN UPPER LOW WEST TOWARD THE AREA FOR TUESDAY. WITH THE DECENT AGREEMENT AMONG THE MODELS ON THE RIDGE THROUGH THE WEEKEND...EXPECT THAT A BLEND WILL BE AN EFFECTIVE STARTING POINT THROUGH SUNDAY. AFTER THAT...WILL LEAN MORE TOWARD THE WEAKER...LESS AMPLIFIED...00Z ECMWF. SENSIBLE WEATHER WILL LIKELY FEATURE SOME ONGOING CONVECTION MOVING SOUTHEAST THROUGH THIS PART OF THE STATE ON THURSDAY MORNING AS A COLD FRONT PASSES THROUGH EARLY IN THE DAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING A RARE SUMMER TIME SHOT OF COOLER AND DRIER AIR FROM THE NORTH. THIS SFC HIGH...AND THE DRY WEATHER...WILL BE SUSTAINED BY THE RIDGING BUILDING ALOFT AND SHOULD SERVE TO KEEP ANY TROPICAL DERIVED MOISTURE OFF TO THE SOUTH AND EAST FOR THE BULK OF THE WEEKEND. HOWEVER...THE RIDGE ALOFT WILL WEAKEN AND MOVE BACK WEST BY LATE SUNDAY WHILE THE CORRESPONDING SFC HIGH WILL ALSO BREAK DOWN AND ALLOW HIGH DEWPOINTS INTO THE REGION FROM THE SOUTHEAST. A DIURNAL REGIME SHOULD THEN GUIDE THE CONVECTIVE DEVELOPMENTS ON MONDAY AND TUESDAY WITH BUILDING INSTABILITY AND LITTLE IN THE WAY OF CAPPING LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON...PARTICULARLY ACROSS OUR SOUTHEAST COUNTIES. THE CR GRID LOAD CAME IN REASONABLE...THOUGH DID ADJUST POPS A BIT ON SUNDAY AND MONDAY NIGHTS TO BETTER EMPHASIZE THE DIURNAL NATURE OF THE CONVECTION. ALSO...TWEAKED OVERNIGHT LOWS ON THURSDAY THROUGH SATURDAY NIGHTS TO ACCOUNT FOR TERRAIN BASED DIFFERENCES IN RADIATIONAL COOLING WHILE WE ARE BENEFITING FROM THE DRIER AIR MASS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 755 PM EDT TUE JUL 9 2013 LOTS OF THUNDERSTORMS NEAR THE TAF STATIONS THIS EVENING. THE RADAR IS INDICATING OUTFLOW BOUNDARIES BEING PRODUCED BY THE THUNDERSTORMS MOVING MANY MILES OUT AHEAD OF THE STORMS. THIS WOULD MEAN THAT AN UNEXPECTED LOW LEVEL WIND SHEAR WELL AHEAD OF THE APPROACHING STORM. LOZ SHOULD BE SEEING A THUNDERSTORM AT THE STATION BETWEEN 00-01Z. FOR FOG AND MIST...WENT WITH PERSISTENCE FOR THE FORECAST. THIS MAY HAVE TO BE RETHOUGHT IF LOZ GET LOTS OF RAIN THIS NEXT HOUR. TOMORROW SHOULD HAVE MORE CONVECTIVE ACTIVITY THAN TODAY WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJ SHORT TERM...RAY LONG TERM...GREIF AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
755 PM EDT TUE JUL 9 2013 .UPDATE... ISSUED AT 755 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE AREA SOUTH AND WEST OF JACKSON GOOD REALLY ACTIVE IN THE LAST FEW HOURS. THE UNSTABLE MOIST AIR WAS REALLY PRIMED...ALL THAT WAS NEEDED WAS THE CONVECTIVE INITIATION. ONE OF THE STORMS GOT REALLY STRONG AND REACHED OUR RADAR BASED SEVERE WEATHER CRITERIA. NO REPORTS HAVE BEEN REPORTED YET. THE MOISTURE LADEN IS CAPABLE OF DUMPING A LOT OF RAIN IN A SHORT TIME. RADAR ESTIMATES OF GREATER THAN TWO INCHES WAS RESPONSIBLE FOR PRODUCING SOME FLASH FLOODING IN THE HOLLY HILL AREA. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 329 PM EDT TUE JUL 9 2013 ISOLD TO SCT SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE AREA THIS AFTERNOON. MORE SUBSTANTIAL AREA OF CONVECTION HAS FIRED OVER OHIO. HRRR HAS ACTUALLY BEEN DOING DECENT WITH CONVECTIVE INITIATION ACROSS AREAS NORTH OF THE OHIO RIVER. IN GENERAL IT KEEPS THE BULK OF ACTIVITY NORTH AND EAST OF OUR CWA...THOUGH RADAR TRENDS WOULD SUGGEST THAT OUR NORTHERN AND EASTERN COUNTIES MAY GET BRUSHED. INCREASED POPS ACROSS THE NORTHERN/EASTERN PORTIONS OF OUR CWA FOR THE LATE AFTERNOON AND EARLY EVENING TIME FRAME. PER THE HRRR...WITH COMPLEX OF STORMS PASSING GENERALLY TO OUR EAST THIS EVENING AND LOSS OF DIURNAL HEATING GRADUALLY DROPPED POPS OFF THROUGH THE NIGHT. HOWEVER...RAMPED POPS BACK UP TOWARDS DAWN AS SHORT TERM HIGH RESOLUTION MODELS SUGGEST THE POSSIBILITY OF THE REMNANTS OF ANOTHER COMPLEX OF STORMS ENTERING THE AREA FROM THE NORTHWEST. OTHERWISE...MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE SHORT TERM. A DEEPENING UPPER LEVEL TROUGH AND REFLECTED SFC COLD FRONT WILL GRADUALLY PUSH THROUGH THE REGION WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. PWATS OVER THE NEXT 36 TO 48 HOURS ARE SIGNIFICANT HITTING CLIMATOLOGICAL HIGHS AT TIMES. FORECAST SOUNDINGS ARE NOT IN AS GOOD AGREEMENT WITH RESPECT TO STORM MOTION THOUGH. THE GFS IS MORE PROGRESSIVE WITH MOVEMENT WHEN COMPARED TO THE HIGHER RESOLUTION RAP AND NAM. REGARDLESS...WITH SUCH HIGH PWATS AND CONSIDERING A FAIRLY SATURATED GROUND FEEL THERE WILL BE THE POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL AND MINOR HYDRO ISSUES...ESPECIALLY WITH THE STRONGER STORMS. CONFIDENCE WAS LACKING WITH RESPECT TO A WIDESPREAD THREAT SO OPTED NOT TO ISSUE ANY TYPE OF FFA. BUT MAY RECONSIDER A FLASH FLOOD WATCH WITH FUTURE FORECAST PACKAGES SHOULD MODELS COME INTO A LITTLE BETTER AGREEMENT WITH RESPECT TO DETAILS...AND SHOW A MORE SIGNIFICANT THREAT. FOR NOW WILL CONTINUE TO COVER THIS POTENTIAL IN THE HWO AND PASS CONCERNS ON TO FUTURE SHIFTS. GENERALLY FOLLOWED INHERITED TEMPS...NUDGING SLIGHTLY TOWARDS A BLEND OF MODEL GUIDANCE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 329 PM EDT TUE JUL 9 2013 THE MODELS HAVE A SIMILAR IDEA...THROUGH THE EXTENDED...OF A MID LEVEL PATTERN DOMINATED BY A LARGE AREA OF RIDGING...INITIALLY OVER THE SOUTHERN ROCKIES EXPANDING NORTHEAST WITH TIME...AND DOWNSTREAM TROUGHING THROUGH THE GREAT LAKES LATER AFFECTING MUCH OF THE EAST AND DEEP SOUTH. THE GREAT LAKES TROUGH STRENGTHENS A BIT ON THURSDAY AS ITS CORE MOVES EAST AND INTO UPSTATE NEW YORK BY 12Z FRIDAY. AT THE SAME TIME...ITS TRAILING AXIS AND MAIN ENERGY BAND WILL SWEEP SOUTHEAST THROUGH THE LOWER OHIO VALLEY AND ACROSS EAST KENTUCKY. THIS WILL ALLOW HEIGHTS TO BUILD IN FROM THE NORTHWEST THROUGH THE WEEKEND WHILE THE SOUTHERN PORTION OF THE TROUGH CUTS OFF OVER THE DEEP SOUTH AND STARTS TO CONSOLIDATE. THOUGH THE MODELS GENERALLY AGREE ON THE RIDGE PLACEMENT...THEY DIFFER ON THE DETAILS REGARDING THE LOWER HEIGHT CENTERS TO THE SOUTH AND EAST. INTO THIS MIX WILL ENTER THE UPPER HEIGHT FIELD OF CHANTAL...OR WHATEVER BECOMES OF HER...THAT COULD MOVE TO THE SOUTHEAST COAST PER THE GEM OR STAY LOCKED OUT TO THE SOUTH AS SEEN IN THE GFS AND ECMWF. EITHER WAY...ITS MOISTURE MAY START TO IMPACT THE AREA AS EARLY AS LATE SUNDAY...LINGERING THROUGH THE REST OF THE EXTENDED. FOR EAST KENTUCKY...THE RIDGE TO THE NORTH WILL BE A KEY COMPONENT IN DETERMINING OUR WEATHER INTO THE START OF NEXT WEEK. WITH THE MODELS IN BETTER AGREEMENT ON THIS FEATURE CONFIDENCE IS HIGHER IN GOING DRY THROUGH AT LEAST MIDDAY SUNDAY. THEREAFTER...THE GFS...AND TO A LESSER EXTENT THE ECMWF...DOES BRING AN UPPER LOW WEST TOWARD THE AREA FOR TUESDAY. WITH THE DECENT AGREEMENT AMONG THE MODELS ON THE RIDGE THROUGH THE WEEKEND...EXPECT THAT A BLEND WILL BE AN EFFECTIVE STARTING POINT THROUGH SUNDAY. AFTER THAT...WILL LEAN MORE TOWARD THE WEAKER...LESS AMPLIFIED...00Z ECMWF. SENSIBLE WEATHER WILL LIKELY FEATURE SOME ONGOING CONVECTION MOVING SOUTHEAST THROUGH THIS PART OF THE STATE ON THURSDAY MORNING AS A COLD FRONT PASSES THROUGH EARLY IN THE DAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING A RARE SUMMER TIME SHOT OF COOLER AND DRIER AIR FROM THE NORTH. THIS SFC HIGH...AND THE DRY WEATHER...WILL BE SUSTAINED BY THE RIDGING BUILDING ALOFT AND SHOULD SERVE TO KEEP ANY TROPICAL DERIVED MOISTURE OFF TO THE SOUTH AND EAST FOR THE BULK OF THE WEEKEND. HOWEVER...THE RIDGE ALOFT WILL WEAKEN AND MOVE BACK WEST BY LATE SUNDAY WHILE THE CORRESPONDING SFC HIGH WILL ALSO BREAK DOWN AND ALLOW HIGH DEWPOINTS INTO THE REGION FROM THE SOUTHEAST. A DIURNAL REGIME SHOULD THEN GUIDE THE CONVECTIVE DEVELOPMENTS ON MONDAY AND TUESDAY WITH BUILDING INSTABILITY AND LITTLE IN THE WAY OF CAPPING LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON...PARTICULARLY ACROSS OUR SOUTHEAST COUNTIES. THE CR GRID LOAD CAME IN REASONABLE...THOUGH DID ADJUST POPS A BIT ON SUNDAY AND MONDAY NIGHTS TO BETTER EMPHASIZE THE DIURNAL NATURE OF THE CONVECTION. ALSO...TWEAKED OVERNIGHT LOWS ON THURSDAY THROUGH SATURDAY NIGHTS TO ACCOUNT FOR TERRAIN BASED DIFFERENCES IN RADIATIONAL COOLING WHILE WE ARE BENEFITING FROM THE DRIER AIR MASS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 755 PM EDT TUE JUL 9 2013 LOTS OF THUNDERSTORMS NEAR THE TAF STATIONS THIS EVENING. THE RADAR IS INDICATING OUTFLOW BOUNDARIES BEING PRODUCED BY THE THUNDERSTORMS MOVING MANY MILES OUT AHEAD OF THE STORMS. THIS WOULD MEAN THAT AN UNEXPECTED LOW LEVEL WIND SHEAR WELL AHEAD OF THE APPROACHING STORM. LOZ SHOULD BE SEEING A THUNDERSTORM AT THE STATION BETWEEN 00-01Z. FOR FOG AND MIST...WENT WITH PERSISTENCE FOR THE FORECAST. THIS MAY HAVE TO BE RETHOUGHT IF LOZ GET LOTS OF RAIN THIS NEXT HOUR. TOMORROW SHOULD HAVE MORE CONVECTIVE ACTIVITY THAN TODAY WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJ SHORT TERM...RAY LONG TERM...GREIF AVIATION...JJ
AREA FORECAST DISCUSSION
NWS PADUCAH KY
640 AM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 640 AM CDT MON JUL 8 2013 REVISED AVIATION DISCUSSION FOR 12Z TAFS. && .SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT) ISSUED AT 329 AM CDT MON JUL 8 2013 A LITTLE BIT OF A BALANCING ACT IN THE SHORT TERM. GIVEN THE SLIGHTLY STRONGER SUBSIDENCE OF THE RIDGE MOVING INTO THE WFO PAH FORECAST AREA FROM THE WEST ON SUNDAY...ANTICIPATE SLIGHTLY BETTER SUBSIDENCE /WARMING/ TODAY...ESPECIALLY IN THE SOUTHERN 1/2 OF SOUTHEAST MO. THERE WILL BE A ZONE OF UNCERTAINTY FOR SHOWER/THUNDERSTORM GENERATION THIS AFTERNOON...MAINLY ALONG AND NORTH OF ROUTE 13 IN SOUTHERN IL...THEN NORTHEAST TO NORTH OF KEHR AND KOWB. LOOKING AT THE LATEST GFS/NAM/RAP/SREF SOUNDINGS SUGGEST FOR ANYTHING TO GET GOING THIS AFTERNOON...IT WOULD HAVE TO COME FROM AIR PARCELS MOVE FROM AROUND 800 MB. EVEN THE MOST UNSTABLE SOUNDINGS STILL HAVE SKINNY CAPE...LITTLE IN THE WAY OF SIGNIFICANT INSTABILITY/BUOYANCY/ MOISTURE TO SUPPORT PERSISTENT AND SUSTAINED UPDRAFTS. FOR NOW...HAVE BLENDED WITH THE HRRR TO HIGHLIGHT ANY ISOLATED THUNDERSTORM CHANCES FOR THIS AFTERNOON...ALBEIT SMALL. FROM A COMPLIMENTARY STANDPOINT...ADJUSTED MAX TEMPERATURES UP SLIGHTLY. FOR NOW...TEMPERATURES THIS AFTERNOON SHOULD KEEP HEAT INDEX VALUES FROM CRITICAL LEVELS THIS AFTERNOON. HOWEVER...FOR TUESDAY AND WEDNESDAY...OUTSIDE OF THE RAIN AREAS...THE SIGNAL HAS BEEN CONSISTENT OVER SOUTHEAST MO AND PARTS OF SOUTHERN IL AND THE PURCHASE AREA OF WEST KENTUCKY FOR MEETING HEAT ADVISORY CRITERIA DURING THE AFTERNOON HOURS...MAINLY FROM 18Z TO 00Z /1 PM TO 7 PM CDT. PLAN ON MENTIONING THIS POTENTIAL IN THE HWO...AS WELL HIGHLIGHTING IT IN A SPECIAL WEATHER STATEMENT. OF COURSE...MOST OF THE POTENTIAL WILL BE OUTSIDE OF RAIN AREAS. TUESDAYS CONVECTIVE ACTIVITY...GIVEN LESSER SHEAR ALOFT...WILL LIKELY BECOME OUTFLOW DOMINATED AS IT DEVELOPS FURTHER SOUTH...WITH A STRONG DIURNAL COMPONENT. FOR WEDNESDAY...AM NOT SURPRISED WITH THE LOCATION OF THE SLIGHT RISK AREA FROM SPC...GIVEN THE SHEAR AND FORCING IN PLACE. STILL BELIEVE HEAVY RAIN WILL BE THE DOMINATE HAZARD. HAIL WILL INITIALLY BE MARGINAL...BUT WIND GUSTS BETWEEN 45 AND 55 MPH MAY BE POSSIBLE. THE SIGNAL FOR THE HIGHEST POPS/WEATHER ON WEDNESDAY HAS BEEN CONSISTENT FOR NEARLY SEVEN DAYS NOW. WITH RESPECT TO TEMPERATURES TUESDAY...WENT A LEAST ANOTHER DEGREE HIGHER AS THE RIDGE STILL HAS SOME INFLUENCE. .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 329 AM CDT MON JUL 8 2013 THE COLD FRONT RESPONSIBLE FOR FOCUSING THE MID WEEK PRECIPITATION EVENT WILL BE DRAPED ALONG OR JUST SOUTH OF THE OHIO RIVER THURSDAY MORNING. A FEW SHOWERS AND THUNDERSTORMS MAY LINGER MAINLY SOUTH AND EAST OF THE OHIO RIVER THURSDAY MORNING BEFORE THE FRONT COMPLETELY SLIPS SOUTH OF THE AREA. LATE IN THE WEEK...HIGH PRESSURE WILL BUILD SOUTH FROM CANADA... BRINGING ANOTHER SPELL OF TEMPERATURES BELOW SEASONAL NORMS. GOOD CONTINUITY AMONG THE RECENT OPERATIONAL AND ENSEMBLE DEPICTIONS FROM THE GFS...ECMWF...AND GEM LENDS RELATIVELY HIGH CONFIDENCE TO THE LATE WEEK FORECAST. ALONG WITH THE MILDER TEMPERATURES WILL COME LESS HUMIDITY...AS DEW POINTS BOTTOM OUT IN THE UPPER 50S AND LOWER 60S FRIDAY AND SATURDAY. IN THE UPPER LEVELS...A BUILDING RIDGE OVER THE CENTRAL U.S. WILL SQUEEZE A TROUGH INTO THE EAST. THIS MAY EVENTUALLY LEAD TO THE DEVELOPMENT OF A CUT-OFF LOW OVER THE SOUTHERN GULF STATES LATE IN THE WEEKEND...BUT THIS IS WHERE FORECAST CONFIDENCE DECREASES MARKEDLY. ENOUGH MOISTURE MAY CREEP NORTH AND WEST INTO THE FORECAST AREA TO WARRANT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS BY SUNDAY. TEMPERATURES WILL GRADUALLY WARM OVER THE WEEKEND AS WELL... BUT SHOULD REMAIN WITHIN SEASONAL RANGE. && .AVIATION... ISSUED AT 640 AM CDT MON JUL 8 2013 DRY WEATHER WITH VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. SCATTERED CU DEVELOPMENT IS EXPECTED BY LATE MORNING...AND MID TO HIGH CLOUDS WILL BE ON THE INCREASE LATER TODAY INTO TONIGHT. PREVAILING WIND WILL BE SOUTHERLY AOB 10 KNOTS. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...SMITH LONG TERM...RJP AVIATION...RJP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
330 AM CDT MON JUL 8 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT) ISSUED AT 329 AM CDT MON JUL 8 2013 A LITTLE BIT OF A BALANCING ACT IN THE SHORT TERM. GIVEN THE SLIGHTLY STRONGER SUBSIDENCE OF THE RIDGE MOVING INTO THE WFO PAH FORECAST AREA FROM THE WEST ON SUNDAY...ANTICIPATE SLIGHTLY BETTER SUBSIDENCE /WARMING/ TODAY...ESPECIALLY IN THE SOUTHERN 1/2 OF SOUTHEAST MO. THERE WILL BE A ZONE OF UNCERTAINTY FOR SHOWER/THUNDERSTORM GENERATION THIS AFTERNOON...MAINLY ALONG AND NORTH OF ROUTE 13 IN SOUTHERN IL...THEN NORTHEAST TO NORTH OF KEHR AND KOWB. LOOKING AT THE LATEST GFS/NAM/RAP/SREF SOUNDINGS SUGGEST FOR ANYTHING TO GET GOING THIS AFTERNOON...IT WOULD HAVE TO COME FROM AIR PARCELS MOVE FROM AROUND 800 MB. EVEN THE MOST UNSTABLE SOUNDINGS STILL HAVE SKINNY CAPE...LITTLE IN THE WAY OF SIGNIFICANT INSTABILITY/BUOYANCY/MOISTURE TO SUPPORT PERSISTENT AND SUSTAINED UPDRAFTS. FOR NOW...HAVE BLENDED WITH THE HRRR TO HIGHLIGHT ANY ISOLATED THUNDERSTORM CHANCES FOR THIS AFTERNOON...ALBEIT SMALL. FROM A COMPLIMENTARY STANDPOINT...ADJUSTED MAX TEMPERATURES UP SLIGHTLY. FOR NOW...TEMPERATURES THIS AFTERNOON SHOULD KEEP HEAT INDEX VALUES FROM CRITICAL LEVELS THIS AFTERNOON. HOWEVER...FOR TUESDAY AND WEDNESDAY...OUTSIDE OF THE RAIN AREAS...THE SIGNAL HAS BEEN CONSISTENT OVER SOUTHEAST MO AND PARTS OF SOUTHERN IL AND THE PURCHASE AREA OF WEST KENTUCKY FOR MEETING HEAT ADVISORY CRITERIA DURING THE AFTERNOON HOURS...MAINLY FROM 18Z TO 00Z /1 PM TO 7 PM CDT. PLAN ON MENTIONING THIS POTENTIAL IN THE HWO...AS WELL HIGHLIGHTING IT IN A SPECIAL WEATHER STATEMENT. OF COURSE...MOST OF THE POTENTIAL WILL BE OUTSIDE OF RAIN AREAS. TUESDAYS CONVECTIVE ACTIVITY...GIVEN LESSER SHEAR ALOFT...WILL LIKELY BECOME OUTFLOW DOMINATED AS IT DEVELOPS FURTHER SOUTH...WITH A STRONG DIURNAL COMPONENT. FOR WEDNESDAY...AM NOT SURPRISED WITH THE LOCATION OF THE SLIGHT RISK AREA FROM SPC...GIVEN THE SHEAR AND FORCING IN PLACE. STILL BELIEVE HEAVY RAIN WILL BE THE DOMINATE HAZARD. HAIL WILL INITIALLY BE MARGINAL...BUT WIND GUSTS BETWEEN 45 AND 55 MPH MAY BE POSSIBLE. THE SIGNAL FOR THE HIGHEST POPS/WEATHER ON WEDNESDAY HAS BEEN CONSISTENT FOR NEARLY SEVEN DAYS NOW. WITH RESPECT TO TEMPERATURES TUESDAY...WENT A LEAST ANOTHER DEGREE HIGHER AS THE RIDGE STILL HAS SOME INFLUENCE. .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 329 AM CDT MON JUL 8 2013 THE COLD FRONT RESPONSIBLE FOR FOCUSING THE MID WEEK PRECIPITATION EVENT WILL BE DRAPED ALONG OR JUST SOUTH OF THE OHIO RIVER THURSDAY MORNING. A FEW SHOWERS AND THUNDERSTORMS MAY LINGER MAINLY SOUTH AND EAST OF THE OHIO RIVER THURSDAY MORNING BEFORE THE FRONT COMPLETELY SLIPS SOUTH OF THE AREA. LATE IN THE WEEK...HIGH PRESSURE WILL BUILD SOUTH FROM CANADA... BRINGING ANOTHER SPELL OF TEMPERATURES BELOW SEASONAL NORMS. GOOD CONTINUITY AMONG THE RECENT OPERATIONAL AND ENSEMBLE DEPICTIONS FROM THE GFS...ECMWF...AND GEM LENDS RELATIVELY HIGH CONFIDENCE TO THE LATE WEEK FORECAST. ALONG WITH THE MILDER TEMPERATURES WILL COME LESS HUMIDITY...AS DEW POINTS BOTTOM OUT IN THE UPPER 50S AND LOWER 60S FRIDAY AND SATURDAY. IN THE UPPER LEVELS...A BUILDING RIDGE OVER THE CENTRAL U.S. WILL SQUEEZE A TROUGH INTO THE EAST. THIS MAY EVENTUALLY LEAD TO THE DEVELOPMENT OF A CUT-OFF LOW OVER THE SOUTHERN GULF STATES LATE IN THE WEEKEND...BUT THIS IS WHERE FORECAST CONFIDENCE DECREASES MARKEDLY. ENOUGH MOISTURE MAY CREEP NORTH AND WEST INTO THE FORECAST AREA TO WARRANT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS BY SUNDAY. TEMPERATURES WILL GRADUALLY WARM OVER THE WEEKEND AS WELL... BUT SHOULD REMAIN WITHIN SEASONAL RANGE. && .AVIATION... ISSUED AT 1238 AM CDT MON JUL 8 2013 DRY WEATHER WITH PRIMARILY VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. A BRIEF PERIOD OF MVFR CONDITIONS IS POSSIBLE AROUND DAYBREAK FROM THE FORMATION OF PATCHY LIGHT FOG. EXPECT SOME CU DEVELOPMENT AGAIN BY LATE MONDAY MORNING. PREVAILING WIND WILL BE SOUTHERLY AOB 10 KNOTS. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...SMITH LONG TERM...RJP AVIATION...RJP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
712 PM EDT TUE JUL 9 2013 .SYNOPSIS... A SERIES OF UPPER DISTURBANCES WILL MAINTAIN CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. A COLD FRONT WILL MOVE THROUGH EARLY THURSDAY...BRINGING COOLER AND MORE COMFORTABLE CONDITIONS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... UPDATED FORECAST TO BRING HIGHER POPS ACROSS ENTIRE FORECAST TONIGHT AS BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS CONTINUE TO MOVE EAST ACROSS NERN OH. ENOUGH SUPPORT FROM A S/W TROUGH ALOFT AND LOW LEVEL INSTABILITY TO KEEP ACTIVITY MOVING E. PREVIOUS DISCUSSION FOLLOWS... AS PREDICTED STORMS ARE FIRING UP ACROSS CENTRAL OHIO AND MOVING SOUTHEAST INTO EAST CENTRAL OHIO. ATMOSPHERE HAS TONS OF ENERGY TO WORK WITH AS ANALYZED BY RAP MODEL. MUCAPES EXCEED 3.0 KJKG-1 WHILE MOISTURE CONV AND EQUIV POT TEMP ADV ARE HIGH SUPPORTING UPSTREAM DEVELOPMENT. BUFR SOUNDINGS SHOW A TROPICAL STATE TO OUR ENVIRONMENT WITH WARM CLOUD PROCESSES IN EFFECT. UPDATED FORECAST TO INCREASE POPS OVER E CENTRAL OHIO AND ADD HEAVY RAIN ATTRIBUTE TO WEATHER GRIDS BASED ON OBSERVED RAINFALL AMOUNTS. LATEST HRRR CONTINUES TO POINTS TO AN MCS TRAVERSING SERN OH AND NRN WV DURING THE OVERNIGHT HOURS. THESE ARE LOCATIONS THAT CAN NOT HANDLE A LOT OF QPF. RAIN AMOUNTS LESS THAN AN INCH PER HOUR WOULD BE ENOUGH TO CREATE FLASH FLOODING. OUR CURRENT FLASH FLOOD WATCH LOOKS GOOD WITH NO CHANGES PLANNED. WITH INCREASED CONFIDENCE PER RECENT HIGH RESOLUTION MODELS...RAISED POP NUMBERS OVER THE AFOREMENTIONED AREA DURING THE NIGHT TIME HOURS. TEMPERATURES WERE LEFT CLOSE TO A BLEND OF GFS LAMP/NAM GUIDANCE TONIGHT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... PCPN ONGOING WED MRNG SHOULD DECR IN CVRG BY MID-MRNG. MDT INSTBY XPCD TO BCM ESTABLISHED THRU FCST AREA BY LATE MRNG OWING TO COOLING MID-LVL TEMPS AND ABUNDANT LOW-LVL MSTR CHARACTERIZED BY DEWPTS IN THE LWR 70S. MRNG CLD CVR XPCD TO BCM BKN AND ALLOW PATCHY HEATING OF THIS VERY MOIST AMS...WHICH WILL AID IN BOTH WEAKENING THE CAP AND STEEPENING LOW-LVL LAPSE RATES. TSTM CVRG XPCD TO INCR MARKEDLY BY EARLY AFTN. DESPITE WEAK MID-LVL FLOW...MDT INSTBY MAY BE SUFFICIENT TO SUPPORT TSTM ORGANIZATION. GIVEN XPCD DRY AIR ATOP DP MOIST LYR...LRG HAIL AND DMGG WIND GUSTS BOTH WILL BE PSBL FROM ANY TSTMS. MRNG CLD CVR WILL RESTRICT HEATING INITIALLY. BUT OVNGT MINIMA IN THE 70S WILL OFFER A HEAD START TO MAXIMA IN THE LWR 80S-MID 80S FOR TMW. PWATS WILL RMN QUITE HIGH THRU WED NGT...PSBLY APRCHG 2.0 IN. SUCH VALUES ARE MORE THAN 2 STANDARD DEVIATIONS ABV NRML VALUES AND WILL ENCOURAGE VERY HIGH PCPN RATES IN TSTMS. FLASH FLOOD WATCH CONTS THRU WED NGT DURG THIS PD OF HIGH PWATS. CDFNT WILL PROGRESS THRU FCST AREA WED NGT...LKLY PROVIDING ADDITIONAL FOCUSED PCPN WED EVE. PCPN WILL SHIFT SEWD OVNGT AND SHOULD VACATE THE FCST AREA BY MID-MRNG THU. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODELS ARE NOW IN BETTER AGREEMENT BUILDING IN HIGH PRESSURE FOR THE WEEKEND. THIS WOULD MEAN DRY AND COMFORTABLE CONDITIONS FOR MUCH OF THE LONG TERM. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... MEDIUM CONFIDENCE FORECAST. VFR WEATHER WILL GIVE WAY TO A BRIEF BOUT OF MVFR CIGS AND VIS AS RW/TRW MOVE ACROSS THE AREA THIS EVNG. YET ANOTHER MID LVL IMPULSE TRACKS ACROSS OVERNIGHT...SO CARRYING PREVAILING RW. THUNDER WILL BE ISOLD SO IT WAS NOT INCLUDED. IFR CIGS WILL ESTABLISH ACR FKL AND DUJ DURING THE PRE DAWN HOURS WHERE BL MOISTURE IS GREATEST. THESE CIGS SHALL LIFT QUICKLY AROUND DAWN AS MID CLOUDS ARRIVE FM THE W. VFR RULES WED...OUTSIDE IF A AIRPORT IS HIT WITH A SHOWER OR THUNDERSTORM. TIMING ISSUES ARE TOUGH...SO HELD OFF FROM PREVAILING WEATHER FOR NOW UNTIL UPSTREAM DEVELOPMENT OCCURS. ZZV COULD SEE A PERIOD OF MVFR HAZE. OUTLOOK.../00Z THURSDAY THROUGH SUNDAY/... IFR WEATHER IS POSSIBLE AGAIN THURSDAY IN SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A COLD FRONT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR MDZ001. OH...FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR OHZ039>041- 049-050-059. FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR OHZ048-057- 058-068-069. PA...FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR PAZ020-021- 029-031-073>076. WV...FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR WVZ001>004- 023-041. FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR WVZ012-021- 022. && $$ SYNOPSIS...34 NEAR TERM...98/34 SHORT TERM...KRAMAR AVIATION...98
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1027 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 401 PM EDT TUE JUL 9 2013 CHANCES OF RAIN SHOWERS AND THUNDERSTORMS WILL OCCUR TONIGHT INTO WEDNESDAY MORNING AS A COLD FRONT APPROACHES THE REGION. BEHIND THE FRONT...HIGH PRESSURE WILL BEGIN TO BUILD IN BY LATE WEDNESDAY...BRINGING COOLER AND LESS HUMID CONDITIONS FOR MIDWEEK. A WARMING TREND WILL THEN FOLLOW FOR LATE IN THE WEEK INTO THE UPCOMING WEEKEND. && .UPDATE... ISSUED AT 1027 PM EDT TUE JUL 9 2013 FIRST LINE OF SHOWERS/EMBEDDED STORMS SOLIDIFIED EARLIER THIS EVENING AND SWEPT THRU FAR NRN LWR MICHIGAN...AND IS NOW IN THE PROCESS OF EXITING INTO FAR NRN LAKE HURON AND FAR ERN UPR MICHIGAN. OUR NEXT WAVE OF CONVECTION IS HEADING EAST ACROSS NRN LAKE MICHIGAN TOWARD NW LWR MICHIGAN. EMBEDDED THUNDERSTORMS WITHIN THIS AREA OF CONVECTION ARE MORE NUMEROUS...AND HAVE UPDATED WX/POPS TO REFLECT THIS. THESE STORMS HAD A HISTORY OF SEVERE WX EARLIER THIS EVENING ACROSS NE WISCONSIN...BUT HAVE SHOWN A DIMINISH IN INTENSITY OVER THE PAST COUPLE OF HOURS WITH LOSS OF DIURNAL INSTABILITY. WILL CERTAINLY KEEP AN EYE ON THIS CONVECTION...BUT FOR NOW IT APPEARS TO BE RELATIVELY BENIGN. MOST OF OUR PRECIP CHANCES WILL COME TO AN END BY AROUND 09Z. WITH JUST A FEW LINGERING SHOWERS ACROSS OUR ERN CWA EARLY WEDNESDAY MORNING BEFORE FROPA AND THE ARRIVAL OF MUCH DRIER AIR BRINGS PRECIP CHANCES TO A CLOSE. UPDATE ISSUED AT 700 PM EDT TUE JUL 9 2013 TWO AREAS OF SHOWERS WITH A FEW EMBEDDED STORMS ARE SLIDING THRU MICHIGAN ATTM. THE NRN AREA OF CONVECTION IS CURRENTLY OVER CENTRAL UPR MICHIGAN HEADING EAST TOWARD ERN UPR MICHIGAN...WHILE THE SRN AREA IS JUST GRAZING OUR SE COUNTIES. IN BETWEEN...A FEW SHOWERS DOT THE NW LWR MICHIGAN LANDSCAPE ATTM. MEANWHILE...A BETTER DEFINED LINE OF STRONGER CONVECTION IS MAKING ITS WAY THRU NE WISCONSIN ATTM...PRODUCING ISOLD SVR STORMS THANKS TO STRONG WIND SHEAR AND BETTER INSTABILITY JUST AHEAD OF THE COLD FRONT. THAT STRONGER INSTABILITY AND SHEAR MAKES A BRIEF APPEARANCE OVER OUR CWA LATER THIS EVENING...BUT ENHANCEMENT FROM DAYTIME INSTABILITY WILL BE WANING BY THEN. CERTAINLY STILL EXPECT SCATTERED SHOWERS AND A FEW STORMS AS WE HEAD THRU THE NIGHT AHEAD OF THE APPROACHING COLD FRONT. BUT STILL DO NOT ANTICIPATE SVR STORMS GIVEN THE TIMING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 401 PM EDT TUE JUL 9 2013 AN ADMITTEDLY FRUSTRATING FORECAST THIS EVENING...WITH CONFIDENCE DWINDLING ABOUT THE POTENTIAL FOR CONVECTION ACROSS THE CWA... DESPITE WHAT SHOULD (THEORETICALLY AT LEAST) BE A DECENT SETUP. EARLY AFTERNOON ANALYSIS REVEALS A PAIR OF SHORTWAVES TRAVERSING A SEASONABLY STRONG JET STREAM FLOW ACROSS THE NORTHERN TIER...WITH THE FIRST OF THESE WAVES JUST NOW ENTERING WESTERN WISCONSIN. THIS FEATURE HAS BEEN RESPONSIBLE FOR A RATHER LONG-LIVED AXIS OF CONVECTION ALL ACROSS THE UPPER MIDWEST OVER THE PAST 12 HOURS...WITH THIS ACTIVITY JUST NOW WORKING ACROSS SOUTHERN LAKE MICHIGAN. THE AIRMASS ACROSS NORTHERN LOWER REMAINS STUBBORNLY CAPPED THANKS TO A WARM NOSE UP AROUND 750MB PER BOTH RUC AND OBSERVED SOUNDINGS...WITH EARLIER THICK CLOUD COVER EFFECTIVELY LIMITING HEATING AND THUS INSTABILITY. ALL THE WHILE...THE BEST BOUNDARY LAYER MOISTURE REMAINS LAID OUT OVER THE SOUTHERN LAKES ALONG A SUBTLE WARM FRONT...WITH MUCAPE VALUES OF 1500-3000 J/KG NOTED IN THE VICINITY OF THIS FEATURE. NOT SURPRISINGLY...CONVECTION IS DOING THE FAMOUS NORTHERN MICHIGAN SPLIT AS OUR AIRMASS IS JUST PLAIN GARBAGE...FOR LACK OF A BETTER TERM...FEATURING ONLY MUCAPE VALUES PERHAPS PUSHING 700J/KG AT BEST AND THE AFOREMENTIONED CAP. MEANWHILE...A SECONDARY/STRONGER UPPER WAVE IS NOTED DIVING INTO THE NORTHERN PLAINS...HERALDING THE ARRIVAL OF A MUCH COOLER AIRMASS... WITH AN ASSOCIATED COLD FRONT DRAPED OVER NORTHWEST MINNESOTA AS OF 19Z. INTO LATE AFTERNOON AND THE EVENING...APPROACH OF LEAD UPPER WAVE WILL MANDATE AT LEAST A CONTINUED CHANCE FOR SHOWERS AND A FEW STORMS...THOUGH HONESTLY JUST NOT FEELING ANY BIG RAIN CHANCES...AS THE REAL BEEFY CONVECTION SHOULD GET GOING OVER THE SOUTHERN LAKES. AS SUCH...AND GIVEN RADAR TRENDS AND STRONG LACK OF ANY UPSTREAM ADDITIONAL ACTIVITY (JUST SOME FLAT CU ACROSS WISCONSIN)...HAVE TO BELIEVE SCATTERED ACTIVITY WILL JUST ABOUT DO IT...AS PERHAPS WE MAY GET LUCKY ENOUGH TO BUBBLE UP A FEW ADDITIONAL SHOWERS WITH THE INCOMING VORT. NO SEVERE WX THREAT WITH EFFECTIVE SHEAR ONLY ABOUT 20 KNOTS. A BIGGER QUESTION COMES TONIGHT AS THE SECONDARY TROUGH AND COLD FRONT ARRIVE. IT WOULD BE NICE TO SEE AT LEAST A LITTLE UPSTREAM ACTIVITY WITH THIS FEATURE...BUT ALAS THERE IS NOTHING AT THE MOMENT...WITH NOTABLE CAPPING IN PLACE BEHIND THE LEAD WAVE. STILL NOT OUT OF THE QUESTION SOME SHOWERS OR A STORM COULD DEVELOP WITH THE UPPER TROUGH THROUGH THE EVENING...PERHAPS PUSHING INTO OUR AREA OVERNIGHT. HAVING SAID THAT...CONFIDENCE IS LOW ENOUGH TO JUST BARELY MAINTAIN SOME CHANCE POPS AT THIS POINT...WITH MAYBE A FEW LINGERING SHOWERS INTO WEDNESDAY MORNING ACROSS EASTERN COUNTIES. FAIRLY LIGHT FLOW IN ADVANCE OF AND SHALLOW NATURE OF INITIAL COLD FRONT MAY AGAIN ALLOW FOR LOW CLOUDS AND SOME FOG TO DEVELOP OVERNIGHT...PARTICULARLY AS THE FLOW VEERS MORE WESTERLY AND TRIES TO PUSH LAKE MICHIGAN GRUNGE BACK ON LAND. WEDNESDAY NOT LOOKING TOO BAD...WITH ANY PRECIP THREAT DONE BY 15Z...BUT PROBABLY SOME PESKY CU/STRATOCU AS MUCH COLDER AIR BLEEDS IN ALOFT. TEMPS NOTABLY COOLER...WITH HUMIDITY LEVELS DIVING AS DEW POINTS MIX INTO THE 50S. COOLER WITH HIGHS MAINLY IN THE 70S...BUT COULD SNEAK IN A FEW LOW 80S SOUTHEAST COUNTIES ON A GUSTY NORTHWEST FLOW...WITH WIND GUSTS UP TO 25 KNOTS EXPECTED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 401 PM EDT TUE JUL 9 2013 RECENT TRENDS...TEMPERATURES: 1-3C ABOVE NORMAL OVER THE LAST WEEK WITH MOST RECENT WARM SPELL...STATE HAS BEEN MOSTLY SPLIT BETWEEN ABOVE NORMAL TEMPERATURES NORTH AND COOLER TEMPERATURES OVER SOUTHERN LOWER WHICH IS THE NORTHERN EXTENT OF A LARGER AREA OF BELOW NORMAL TEMPERATURES TO START JULY ACROSS THE MID/LOWER MISSISSIPPI VALLEY/OHIO VALLEY AND INTO THE SOUTHEAST THANKS TO RECENT HEAVY RAINFALL. PRECIPITATION/HYDROLOGY: BAND OF MUCH NEEDED RAINFALL YESTERDAY BETWEEN THE M-32 AND M-55 CORRIDORS WITH WIDESPREAD 0.50+ INCH AMOUNTS AND AREAS OF 1-2 INCH AMOUNTS. EASTERN UPPER/TIP OF THE MITT STILL DRY THOUGH...LAST MEASURABLE PRECIP IN THE SAULT WAS JUNE 28. 30 DAY STANDARDIZED PRECIP INDEX CONTINUES ON A DRIER TRENDS ESPECIALLY ACROSS EASTERN UPPER. NORTHERN MICHIGAN SOIL MOISTURE CONTINUES TO DRY OUT (STILL NEAR NORMAL...ABOVE NORMAL NOW CONFINED TO CENTRAL/SOUTHERN LOWER MICHIGAN). SEVEN DAY MEAN DISCHARGE ON AREA RIVERS MOSTLY NEAR NORMAL. LATEST GREAT LAKES LEVELS FORECAST FROM THE ARMY CORPS SHOWS LAKES MICHIGAN/HURON CURRENTLY ABOUT 2 FEET BELOW NORMAL... WITH LITTLE IMPROVEMENT FORECAST THROUGH THE FALL. LARGE SCALE PATTERN/FORECAST...FLAT/EXPANSIVE RIDGE SPANS THE SOUTHERN CONUS AND EXTENDS EAST ACROSS THE SUBTROPICAL ATLANTIC TO THE IBERIAN PENINSULA. MAINLY ZONAL BAND OF WESTERLIES TO THE NORTH OF THIS RIDGE CROSSING THE NORTHERN TIER OF STATES AND ACROSS THE GREAT LAKES...ALL PART OF A LOW AMPLITUDE 4/5 WAVE HEMISPHERIC PATTERN. SHORT WAVE TROUGH MOVING THROUGH THIS BAND OF WESTERLIES ACROSS THE HIGH PLAINS TODAY IS FORECAST TO STRENGTHEN AS IT MOVES INTO THE GREAT LAKES WEDNESDAY AND HOOKS UP WITH HIGH LATITUDE TROUGHING OVER THE ARCTIC TO COOL THINGS OFF FOR A COUPLE OF DAYS. THIS TROUGH WILL SERVE TO SPLIT THE SOUTHERN CONUS RIDGE...ALLOWING HIGHER HEIGHTS TO CONSOLIDATE OVER THE CENTRAL/SOUTHERN PLAINS BY FRIDAY (AND OPEN UP A CHANNEL TO DRAW TROPICAL CYCLONE "CHANTAL" TO THE NORTHWEST TOWARD THE SOUTHEASTERN U.S.). RISING HEIGHTS APPEAR TO BE IN THE OFFING FOR THE UPPER LAKES HEADING INTO THE WEEKEND AS UPPER RIDGE AXIS POKES ITS WAY NORTHEAST...THEN PERHAPS SOME SORT OF BOUNDARY THAT SETTLES IN EARLY NEXT WEEK WITH A FAIRLY STRONG HEIGHT GRADIENT ACROSS CANADA. FORECAST AREA SHOULD BE FIRMLY WITHIN POST-FRONTAL AIR MASS BY WEDNESDAY EVENING AS NORTHWEST BOUNDARY LAYER FLOW PULLS COOLER/ DRIER AIR ACROSS THE UPPER LAKES. TRAILING SHORT WAVE TROUGH WILL FOLLOW LATER WEDNESDAY NIGHT BUT HEIGHT RISES ALOFT AND RISING SURFACE PRESSURES TO ARRIVE THURSDAY...WITH HIGH PRESSURE HOLDING ON INTO FRIDAY. SO FORECAST CONCERNS IN THE NEAR TERM WEDNESDAY NIGHT THROUGH FRIDAY...WEATHER: NOT MUCH AT THIS POINT. SHORT WAVE TROUGH SWINGS THROUGH WEDNESDAY NIGHT...BUT MAY NOT HAVE MUCH MORE THAN SOME MID CLOUD WITH IT. LOW LEVEL THERMAL TROUGH WILL MOVE THROUGH LOWER MICHIGAN DURING THE FIRST HALF OF THURSDAY...MAY ALLOW FOR SOME DIURNALLY FORCED CLOUDS TO POP ACROSS INTERIOR NORTH CENTRAL/NORTHEAST LOWER. BEYOND THAT WEATHER CONCERNS MINIMAL THURSDAY NIGHT (CHILLY) AND FRIDAY. TEMPERATURES...WEDNESDAY NIGHT LOWS MAINLY IN THE 50S...HIGHS THURSDAY PROBABLY A COUPLE DEGREES BELOW SEASONABLE NORMS (MOSTLY 70S). GOOD RADIATIONAL COOLING NIGHT IN STORE THURSDAY NIGHT... FRIDAY MORNING LOWS DOWN IN THE 40S AS A RESULT. HIGHS FRIDAY EXPECTED TO BE CLOSER TO NORMAL (UPPER 70S/LOWER 80S). WINDS...NORTHWEST 10-15 TO START WEDNESDAY EVENING THEN DIMINISHING. NORTH/NORTHWEST 5-15MPH DURING THE DAY THURSDAY THEN BECOMING MOSTLY CALM THURSDAY NIGHT. FRIDAY WINDS SOUTH 5-10MPH EASTERN UPPER... MOSTLY LIGHT/VARIABLE SOUTH OF THE BRIDGE WITH PREDOMINANT LAKE BREEZE CIRCULATIONS RESULTING IN ONSHORE FLOW ALONG THE LAKESHORES. EXTENDED FORECAST (SATURDAY THROUGH TUESDAY)...WILL CONTINUE TO WARM UP SATURDAY AND EXPECTING ANOTHER DRY DAY WITH HIGHS WELL INTO THE 80S. RAIN CHANCES MAY START TO INCREASE SATURDAY NIGHT INTO SUNDAY ESPECIALLY FARTHER NORTH WHERE MAY SEE INCREASED FOCUS ALONG A LOW LEVEL JET. AFTER THAT...HEIGHT FALLS SPREAD INTO CENTRAL/EASTERN CANADA WITH AN ASSOCIATED FRONTAL BOUNDARY FORECAST TO GET STRETCHED OUT IN THE VICINITY OF THE UPPER LAKES. WHETHER SAID BOUNDARY DROPS IN CLOSE ENOUGH TO FOCUS SHOWER/THUNDERSTORM CHANCES EARLY NEXT WEEK IS UNCERTAIN...MAY TRY TO GO DRY MONDAY AND START TUESDAY OUT WITH SOME RAIN CHANCES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 700 PM EDT TUE JUL 9 2013 SCATTERED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL CONTINUE TO IMPACT NRN LWR MICHIGAN TONIGHT AHEAD OF A COLD FRONT SCHEDULED TO SLIDE THRU OUR REGION EARLY WEDNESDAY. CONDITIONS WILL AGAIN DETERIORATE TO IFR TONIGHT THANKS TO AMPLE LOW LEVEL MOISTURE RESULTING IN THE DEVELOPMENT OF LOW STRATUS AND FOG. LIGHT/VARIABLE WINDS TONIGHT WILL SHIFT TO THE NW ON WEDNESDAY AND STRENGTHEN TO 15 TO 25 KTS. && .MARINE... ISSUED AT 401 PM EDT TUE JUL 9 2013 FAIRLY LIGHT AND VARIABLE FLOW WILL CONTINUE ON THE GREAT LAKES FOR MUCH OF TONIGHT...AS AREAS OF FOG AND LOW CLOUDS ALSO PERSIST. WINDS WILL SHIFT ABRUPTLY OUT OF THE WEST TO NORTHWEST ON WEDNESDAY...WITH SMALL CRAFT ADVISORY CONDITIONS EXPECTED ACROSS PARTS OF THE NEARSHORE WATERS...MAINLY THROUGH THE STRAITS AND ACROSS NORTHERN LAKE HURON AND WHITEFISH BAY. THOSE GUSTY CONDITIONS WILL SLOWLY ABATE INTO WEDNESDAY NIGHT...WITH AN EXTENDED PERIOD OF LIGHT WINDS AND FAIRLY LOW WAVES FORESEEN TO WRAP UP THE WORK WEEK AS HIGH PRESSURE DRIFTS OVER THE WATERS. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...MR SYNOPSIS...NTS SHORT TERM...LAWRENCE LONG TERM...JPB AVIATION...MR MARINE...LAWRENCE
AREA FORECAST DISCUSSION
NWS GAYLORD MI
701 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 401 PM EDT TUE JUL 9 2013 CHANCES OF RAIN SHOWERS AND THUNDERSTORMS WILL OCCUR TONIGHT INTO WEDNESDAY MORNING AS A COLD FRONT APPROACHES THE REGION. BEHIND THE FRONT...HIGH PRESSURE WILL BEGIN TO BUILD IN BY LATE WEDNESDAY...BRINGING COOLER AND LESS HUMID CONDITIONS FOR MIDWEEK. A WARMING TREND WILL THEN FOLLOW FOR LATE IN THE WEEK INTO THE UPCOMING WEEKEND. && .UPDATE... ISSUED AT 700 PM EDT TUE JUL 9 2013 TWO AREAS OF SHOWERS WITH A FEW EMBEDDED STORMS ARE SLIDING THRU MICHIGAN ATTM. THE NRN AREA OF CONVECTION IS CURRENTLY OVER CENTRAL UPR MICHIGAN HEADING EAST TOWARD ERN UPR MICHIGAN...WHILE THE SRN AREA IS JUST GRAZING OUR SE COUNTIES. IN BETWEEN...A FEW SHOWERS DOT THE NW LWR MICHIGAN LANDSCAPE ATTM. MEANWHILE...A BETTER DEFINED LINE OF STRONGER CONVECTION IS MAKING ITS WAY THRU NE WISCONSIN ATTM...PRODUCING ISOLD SVR STORMS THANKS TO STRONG WIND SHEAR AND BETTER INSTABILITY JUST AHEAD OF THE COLD FRONT. THAT STRONGER INSTABILITY AND SHEAR MAKES A BRIEF APPEARANCE OVER OUR CWA LATER THIS EVENING...BUT ENHANCEMENT FROM DAYTIME INSTABILITY WILL BE WANING BY THEN. CERTAINLY STILL EXPECT SCATTERED SHOWERS AND A FEW STORMS AS WE HEAD THRU THE NIGHT AHEAD OF THE APPROACHING COLD FRONT. BUT STILL DO NOT ANTICIPATE SVR STORMS GIVEN THE TIMING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 401 PM EDT TUE JUL 9 2013 AN ADMITTEDLY FRUSTRATING FORECAST THIS EVENING...WITH CONFIDENCE DWINDLING ABOUT THE POTENTIAL FOR CONVECTION ACROSS THE CWA... DESPITE WHAT SHOULD (THEORETICALLY AT LEAST) BE A DECENT SETUP. EARLY AFTERNOON ANALYSIS REVEALS A PAIR OF SHORTWAVES TRAVERSING A SEASONABLY STRONG JET STREAM FLOW ACROSS THE NORTHERN TIER...WITH THE FIRST OF THESE WAVES JUST NOW ENTERING WESTERN WISCONSIN. THIS FEATURE HAS BEEN RESPONSIBLE FOR A RATHER LONG-LIVED AXIS OF CONVECTION ALL ACROSS THE UPPER MIDWEST OVER THE PAST 12 HOURS...WITH THIS ACTIVITY JUST NOW WORKING ACROSS SOUTHERN LAKE MICHIGAN. THE AIRMASS ACROSS NORTHERN LOWER REMAINS STUBBORNLY CAPPED THANKS TO A WARM NOSE UP AROUND 750MB PER BOTH RUC AND OBSERVED SOUNDINGS...WITH EARLIER THICK CLOUD COVER EFFECTIVELY LIMITING HEATING AND THUS INSTABILITY. ALL THE WHILE...THE BEST BOUNDARY LAYER MOISTURE REMAINS LAID OUT OVER THE SOUTHERN LAKES ALONG A SUBTLE WARM FRONT...WITH MUCAPE VALUES OF 1500-3000 J/KG NOTED IN THE VICINITY OF THIS FEATURE. NOT SURPRISINGLY...CONVECTION IS DOING THE FAMOUS NORTHERN MICHIGAN SPLIT AS OUR AIRMASS IS JUST PLAIN GARBAGE...FOR LACK OF A BETTER TERM...FEATURING ONLY MUCAPE VALUES PERHAPS PUSHING 700J/KG AT BEST AND THE AFOREMENTIONED CAP. MEANWHILE...A SECONDARY/STRONGER UPPER WAVE IS NOTED DIVING INTO THE NORTHERN PLAINS...HERALDING THE ARRIVAL OF A MUCH COOLER AIRMASS... WITH AN ASSOCIATED COLD FRONT DRAPED OVER NORTHWEST MINNESOTA AS OF 19Z. INTO LATE AFTERNOON AND THE EVENING...APPROACH OF LEAD UPPER WAVE WILL MANDATE AT LEAST A CONTINUED CHANCE FOR SHOWERS AND A FEW STORMS...THOUGH HONESTLY JUST NOT FEELING ANY BIG RAIN CHANCES...AS THE REAL BEEFY CONVECTION SHOULD GET GOING OVER THE SOUTHERN LAKES. AS SUCH...AND GIVEN RADAR TRENDS AND STRONG LACK OF ANY UPSTREAM ADDITIONAL ACTIVITY (JUST SOME FLAT CU ACROSS WISCONSIN)...HAVE TO BELIEVE SCATTERED ACTIVITY WILL JUST ABOUT DO IT...AS PERHAPS WE MAY GET LUCKY ENOUGH TO BUBBLE UP A FEW ADDITIONAL SHOWERS WITH THE INCOMING VORT. NO SEVERE WX THREAT WITH EFFECTIVE SHEAR ONLY ABOUT 20 KNOTS. A BIGGER QUESTION COMES TONIGHT AS THE SECONDARY TROUGH AND COLD FRONT ARRIVE. IT WOULD BE NICE TO SEE AT LEAST A LITTLE UPSTREAM ACTIVITY WITH THIS FEATURE...BUT ALAS THERE IS NOTHING AT THE MOMENT...WITH NOTABLE CAPPING IN PLACE BEHIND THE LEAD WAVE. STILL NOT OUT OF THE QUESTION SOME SHOWERS OR A STORM COULD DEVELOP WITH THE UPPER TROUGH THROUGH THE EVENING...PERHAPS PUSHING INTO OUR AREA OVERNIGHT. HAVING SAID THAT...CONFIDENCE IS LOW ENOUGH TO JUST BARELY MAINTAIN SOME CHANCE POPS AT THIS POINT...WITH MAYBE A FEW LINGERING SHOWERS INTO WEDNESDAY MORNING ACROSS EASTERN COUNTIES. FAIRLY LIGHT FLOW IN ADVANCE OF AND SHALLOW NATURE OF INITIAL COLD FRONT MAY AGAIN ALLOW FOR LOW CLOUDS AND SOME FOG TO DEVELOP OVERNIGHT...PARTICULARLY AS THE FLOW VEERS MORE WESTERLY AND TRIES TO PUSH LAKE MICHIGAN GRUNGE BACK ON LAND. WEDNESDAY NOT LOOKING TOO BAD...WITH ANY PRECIP THREAT DONE BY 15Z...BUT PROBABLY SOME PESKY CU/STRATOCU AS MUCH COLDER AIR BLEEDS IN ALOFT. TEMPS NOTABLY COOLER...WITH HUMIDITY LEVELS DIVING AS DEW POINTS MIX INTO THE 50S. COOLER WITH HIGHS MAINLY IN THE 70S...BUT COULD SNEAK IN A FEW LOW 80S SOUTHEAST COUNTIES ON A GUSTY NORTHWEST FLOW...WITH WIND GUSTS UP TO 25 KNOTS EXPECTED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 401 PM EDT TUE JUL 9 2013 RECENT TRENDS...TEMPERATURES: 1-3C ABOVE NORMAL OVER THE LAST WEEK WITH MOST RECENT WARM SPELL...STATE HAS BEEN MOSTLY SPLIT BETWEEN ABOVE NORMAL TEMPERATURES NORTH AND COOLER TEMPERATURES OVER SOUTHERN LOWER WHICH IS THE NORTHERN EXTENT OF A LARGER AREA OF BELOW NORMAL TEMPERATURES TO START JULY ACROSS THE MID/LOWER MISSISSIPPI VALLEY/OHIO VALLEY AND INTO THE SOUTHEAST THANKS TO RECENT HEAVY RAINFALL. PRECIPITATION/HYDROLOGY: BAND OF MUCH NEEDED RAINFALL YESTERDAY BETWEEN THE M-32 AND M-55 CORRIDORS WITH WIDESPREAD 0.50+ INCH AMOUNTS AND AREAS OF 1-2 INCH AMOUNTS. EASTERN UPPER/TIP OF THE MITT STILL DRY THOUGH...LAST MEASURABLE PRECIP IN THE SAULT WAS JUNE 28. 30 DAY STANDARDIZED PRECIP INDEX CONTINUES ON A DRIER TRENDS ESPECIALLY ACROSS EASTERN UPPER. NORTHERN MICHIGAN SOIL MOISTURE CONTINUES TO DRY OUT (STILL NEAR NORMAL...ABOVE NORMAL NOW CONFINED TO CENTRAL/SOUTHERN LOWER MICHIGAN). SEVEN DAY MEAN DISCHARGE ON AREA RIVERS MOSTLY NEAR NORMAL. LATEST GREAT LAKES LEVELS FORECAST FROM THE ARMY CORPS SHOWS LAKES MICHIGAN/HURON CURRENTLY ABOUT 2 FEET BELOW NORMAL... WITH LITTLE IMPROVEMENT FORECAST THROUGH THE FALL. LARGE SCALE PATTERN/FORECAST...FLAT/EXPANSIVE RIDGE SPANS THE SOUTHERN CONUS AND EXTENDS EAST ACROSS THE SUBTROPICAL ATLANTIC TO THE IBERIAN PENINSULA. MAINLY ZONAL BAND OF WESTERLIES TO THE NORTH OF THIS RIDGE CROSSING THE NORTHERN TIER OF STATES AND ACROSS THE GREAT LAKES...ALL PART OF A LOW AMPLITUDE 4/5 WAVE HEMISPHERIC PATTERN. SHORT WAVE TROUGH MOVING THROUGH THIS BAND OF WESTERLIES ACROSS THE HIGH PLAINS TODAY IS FORECAST TO STRENGTHEN AS IT MOVES INTO THE GREAT LAKES WEDNESDAY AND HOOKS UP WITH HIGH LATITUDE TROUGHING OVER THE ARCTIC TO COOL THINGS OFF FOR A COUPLE OF DAYS. THIS TROUGH WILL SERVE TO SPLIT THE SOUTHERN CONUS RIDGE...ALLOWING HIGHER HEIGHTS TO CONSOLIDATE OVER THE CENTRAL/SOUTHERN PLAINS BY FRIDAY (AND OPEN UP A CHANNEL TO DRAW TROPICAL CYCLONE "CHANTAL" TO THE NORTHWEST TOWARD THE SOUTHEASTERN U.S.). RISING HEIGHTS APPEAR TO BE IN THE OFFING FOR THE UPPER LAKES HEADING INTO THE WEEKEND AS UPPER RIDGE AXIS POKES ITS WAY NORTHEAST...THEN PERHAPS SOME SORT OF BOUNDARY THAT SETTLES IN EARLY NEXT WEEK WITH A FAIRLY STRONG HEIGHT GRADIENT ACROSS CANADA. FORECAST AREA SHOULD BE FIRMLY WITHIN POST-FRONTAL AIR MASS BY WEDNESDAY EVENING AS NORTHWEST BOUNDARY LAYER FLOW PULLS COOLER/ DRIER AIR ACROSS THE UPPER LAKES. TRAILING SHORT WAVE TROUGH WILL FOLLOW LATER WEDNESDAY NIGHT BUT HEIGHT RISES ALOFT AND RISING SURFACE PRESSURES TO ARRIVE THURSDAY...WITH HIGH PRESSURE HOLDING ON INTO FRIDAY. SO FORECAST CONCERNS IN THE NEAR TERM WEDNESDAY NIGHT THROUGH FRIDAY...WEATHER: NOT MUCH AT THIS POINT. SHORT WAVE TROUGH SWINGS THROUGH WEDNESDAY NIGHT...BUT MAY NOT HAVE MUCH MORE THAN SOME MID CLOUD WITH IT. LOW LEVEL THERMAL TROUGH WILL MOVE THROUGH LOWER MICHIGAN DURING THE FIRST HALF OF THURSDAY...MAY ALLOW FOR SOME DIURNALLY FORCED CLOUDS TO POP ACROSS INTERIOR NORTH CENTRAL/NORTHEAST LOWER. BEYOND THAT WEATHER CONCERNS MINIMAL THURSDAY NIGHT (CHILLY) AND FRIDAY. TEMPERATURES...WEDNESDAY NIGHT LOWS MAINLY IN THE 50S...HIGHS THURSDAY PROBABLY A COUPLE DEGREES BELOW SEASONABLE NORMS (MOSTLY 70S). GOOD RADIATIONAL COOLING NIGHT IN STORE THURSDAY NIGHT... FRIDAY MORNING LOWS DOWN IN THE 40S AS A RESULT. HIGHS FRIDAY EXPECTED TO BE CLOSER TO NORMAL (UPPER 70S/LOWER 80S). WINDS...NORTHWEST 10-15 TO START WEDNESDAY EVENING THEN DIMINISHING. NORTH/NORTHWEST 5-15MPH DURING THE DAY THURSDAY THEN BECOMING MOSTLY CALM THURSDAY NIGHT. FRIDAY WINDS SOUTH 5-10MPH EASTERN UPPER... MOSTLY LIGHT/VARIABLE SOUTH OF THE BRIDGE WITH PREDOMINANT LAKE BREEZE CIRCULATIONS RESULTING IN ONSHORE FLOW ALONG THE LAKESHORES. EXTENDED FORECAST (SATURDAY THROUGH TUESDAY)...WILL CONTINUE TO WARM UP SATURDAY AND EXPECTING ANOTHER DRY DAY WITH HIGHS WELL INTO THE 80S. RAIN CHANCES MAY START TO INCREASE SATURDAY NIGHT INTO SUNDAY ESPECIALLY FARTHER NORTH WHERE MAY SEE INCREASED FOCUS ALONG A LOW LEVEL JET. AFTER THAT...HEIGHT FALLS SPREAD INTO CENTRAL/EASTERN CANADA WITH AN ASSOCIATED FRONTAL BOUNDARY FORECAST TO GET STRETCHED OUT IN THE VICINITY OF THE UPPER LAKES. WHETHER SAID BOUNDARY DROPS IN CLOSE ENOUGH TO FOCUS SHOWER/THUNDERSTORM CHANCES EARLY NEXT WEEK IS UNCERTAIN...MAY TRY TO GO DRY MONDAY AND START TUESDAY OUT WITH SOME RAIN CHANCES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 700 PM EDT TUE JUL 9 2013 SCATTERED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL CONTINUE TO IMPACT NRN LWR MICHIGAN TONIGHT AHEAD OF A COLD FRONT SCHEDULED TO SLIDE THRU OUR REGION EARLY WEDNESDAY. CONDITIONS WILL AGAIN DETERIORATE TO IFR TONIGHT THANKS TO AMPLE LOW LEVEL MOISTURE RESULTING IN THE DEVELOPMENT OF LOW STRATUS AND FOG. LIGHT/VARIABLE WINDS TONIGHT WILL SHIFT TO THE NW ON WEDNESDAY AND STRENGTHEN TO 15 TO 25 KTS. && .MARINE... ISSUED AT 401 PM EDT TUE JUL 9 2013 FAIRLY LIGHT AND VARIABLE FLOW WILL CONTINUE ON THE GREAT LAKES FOR MUCH OF TONIGHT...AS AREAS OF FOG AND LOW CLOUDS ALSO PERSIST. WINDS WILL SHIFT ABRUPTLY OUT OF THE WEST TO NORTHWEST ON WEDNESDAY...WITH SMALL CRAFT ADVISORY CONDITIONS EXPECTED ACROSS PARTS OF THE NEARSHORE WATERS...MAINLY THROUGH THE STRAITS AND ACROSS NORTHERN LAKE HURON AND WHITEFISH BAY. THOSE GUSTY CONDITIONS WILL SLOWLY ABATE INTO WEDNESDAY NIGHT...WITH AN EXTENDED PERIOD OF LIGHT WINDS AND FAIRLY LOW WAVES FORESEEN TO WRAP UP THE WORK WEEK AS HIGH PRESSURE DRIFTS OVER THE WATERS. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...MR SYNOPSIS...NTS SHORT TERM...LAWRENCE LONG TERM...JPB AVIATION...MR MARINE...LAWRENCE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
147 PM EDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON JUL 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA. AT THE SFC...A FRONTAL BOUNDARY EXTENDED ACROSS NRN WI THROUGH SRN UPPER MI. A SHORTWAVE TROUGH FROM NRN ONTARIO THROUGH WRN LAKE SUPERIOR INTO NW WI SUPPORTED A LARGE AREA OF SHOWERS AND THUNDERSTORMS ACROSS CNTRL UPPER MI INTO NE WI AND NRN LAKE MICHIGAN. EVEN THOUGH THE GREATER MUCAPE VALUES OF 500-1000 J/KG AND STRONGER TSRA WERE LOCATED ALONG AND SOUTH OF THE FRONT...FORCING ASSOCIATED WITH THE SHRTWV WAS STRONG ENOUGH TO SUPPORT TSRA OVER N CNTRL UPPER MI. MANY LOCATIONS FROM GOGEBIC COUNTY THROUGH SRN UPPER MI HAVE RECEIVED RAINFALL AMOUNTS IN THE 1 TO 2 INCH RANGE...PER RADAR ESTIMATES. TODAY...EXPECT THAT AS THE SHRTWV MOVES OFF TO THE EAST THIS MORNING...THE SHRA/TSRA WILL ALSO SHIFT INTO THE ERN CWA. WITH SOME CLEARING IN THE AFTERNOON...TEMPS COULD AGAIN REBOUND TO THE LOWER 80S OVER THE SOUTH HALF OF UPPER MICHIGAN. EVEN THOUGH THIS WOULD BOOST MLCAPE VALUES BACK INTO THE 1K-2K J/KG RANGE...WITH MID LEVEL RIDGING AND WEAK QVECTOR DIV BUILDING INTO THE AREA IN THE WAKE OF THE SHORTWAVE....PCPN CHANCES WILL BE MINIMAL. NEVERTHELESS...SOME ISOLD SHRA/TSRA WILL STILL BE POSSIBLE...MAINLY OVER THE S CNTRL CWA WHERE MODELS SUGGEST A WEAK SFC TROUGH AXIS WOULD MAXIMIZE LOW LEVEL CONVERGENCE. TONIGHT...WEAK MID-LEVEL RIDGING SHOULD AND LOSS OF DAYTIME HEATING SHOULD BRING AN END TO ANY LINGERING PCPN. MID LEVEL DRYING AND A DEVELOPING SUBSIDENCE INVERSION ABOVE LINGERING LOW-LEVEL MOISTURE WILL FAVOR ANOTHER ROUND OF FOG ACROSS INTERIOR LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 508 AM EDT MON JUL 8 2013 THE MODELS CONTINUE TO AGREE ON THE GENERAL IDEA THAT AN MCS WILL BE ONGOING AT THE START OF THE PERIOD NEAR THE NOSE OF THE 40-45KT LLJ OVER THE UPPER MISSISSIPPI VALLEY. HOWEVER...THERE TENDS TO BE SOME MODEL DISAGREEMENT ON THE EXACT PLACEMENT OF THE MCS...WHICH WILL PROVE CRITICAL IN THE PRECIPITATION AND POP FORECAST ESPECIALLY TUESDAY AFTERNOON INTO TUESDAY EVENING. IN GENERAL...THE MODELS HAVE TRENDED NORTHWARD WITH THE NOSE OF THE LOW LEVEL JET. THE REGIONAL GEM IS THE MOST AGGRESSIVE...WITH THE BEST LOW LEVEL JET ENERGY FOCUSED WELL INTO NRN MN AND WESTERN LAKE SUPERIOR TUESDAY...WHILE THE NAM AND GFS SUPPRESS IT FURTHER SOUTH INTO CENTRAL WI AND SOUTH-CENTRAL UPPER MI RESPECTIVELY. DUE TO CONVECTIVE FEEDBACK FROM BOTH THE MODELS...IT IS UNCLEAR WHERE THIS MCS WILL TRACK ON TUESDAY...HOWEVER CLIMATOLOGY...PAST EXPERIENCE AND MODEL FORWARD PROPAGATING CORFIDI VECTORS WOULD SUGGEST THAT ANY MCS OVER SOUTHERN/CENTRAL MN TUE MORNING WOULD LIKELY STAY NEAR OR JUST SOUTH OF THE WI/MI BORDER AND PERHAPS CLIP MENOMINEE COUNTY LATER TUESDAY AFTERNOON. THIS SCENARIO WOULD POTENTIALLY LEAVE MUCH OF UPPER MICHIGAN DRY ON TUESDAY OR JUST WITH RESIDUAL STRATIFORM RAIN AND EMBEDDED THUNDER TUE AFTN INTO THE EVENING. IN ADDITION...THIS MCS MAY HELP DISRUPT THE MOISTURE INFLOW INTO THE MAIN SYSTEM AND COLD FRONT OVER THE NRN PLAINS/NW ONTARIO LATER TUESDAY INTO TUESDAY NIGHT. RESIDUAL CLOUD COVER BLOWOFF FROM THE MCS MAY ALSO ALLOW FOR DIMINISHED INSTABILITY ACROSS THE REGION AS THE COLD FRONT APPROACHES FROM THE NORTHWEST TUESDAY NIGHT. AS SUCH...AS PREVIOUS FORECASTS HAVE INDICATED...CONFIDENCE REMAINS RATHER LOW REGARDING THE POP/QPF FORECAST TUESDAY AFTERNOON INTO TUESDAY NIGHT. FOR NOW...HAVE MAINTAINED LIKELY POPS ACROSS THE SOUTH CENTRAL TUE AFTN WITH CHANCE POPS ELSEWHERE. FOR TUESDAY NIGHT...HAVE OPTED TO GO WITH LIKELY POPS NEAR LAKE MICHIGAN WITH CHANCE POPS ELSEWHERE AS THE MAIN UPPER WAVE AND ASSOCIATED COLD FRONT PASS THROUGH. MUCH LESS HUMID AND MORE SEASONABLE TEMPS ON WEDNESDAY BEHIND THE COLD FRONT. CANNOT RULE OUT A PASSING SHOWER EARLY ACROSS THE EASTERN HALF OF UPPER MI EARLY WED MORNING AS THE UPPER TROUGH AXIS WILL HAVE YET TO PASS THROUGH. OTHERWISE...HIGH PRESSURE WILL BUILD ACROSS THE AREA WED NIGHT-THURSDAY LEADING TO VERY SEASONABLE AND DRY CONDITIONS. UPPER HEIGHTS BUILD ON FRIDAY ACROSS THE WESTERN LAKES...GIVING SOME WARMER TEMPS BUT DRY CONDITIONS WILL CONTINUE. ON SATURDAY...THE GFS AND 00Z ECMWF ARE IN BETTER AGREEMENT IN SHOWING A WEAK DISTURBANCE MOVING OVER THE RIDGE AXIS. ALTHOUGH MOISTURE WILL BE LACKING...CANNOT TOTALLY RULE OUT SHOWERS/STORMS ACROSS THE WEST SAT AFTN AS AS SUCH HAVE ADDED A 30 PCT CHANCE ON SATURDAY. NEXT SYSTEM MOVES INTO THE WESTERN LAKES LATE IN THE WEEKEND OR EARLY MONDAY. STILL SOME TIMING ISSUES WITH THE ECMWF BEING FASTER THAN THE GFS. WITH THIS IN MIND...HAVE KEPT ANY MENTION OF PRECIPITATION OUT OF THE FORECAST FOR SUNDAY...BUT MAY NEED TO BE INTRODUCED IN LATER FORECASTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 146 PM EDT MON JUL 8 2013 VLIFR CONDITIONS EXPECTED TO DEVELOP AT ALL SITES OVERNIGHT. PLENTY OF LOW-LEVEL MOISTURE HAS BEEN HANGING AROUND TODAY...WITH ALL SITES FINALLY STARTING TO MIX ENOUGH TO BREAK OUT OF IFR STRATUS. TO MAKE THINGS COMPLICATED...ALL SITES ARE CURRENTLY EXPOSED TO UPSLOPE FLOW...WHICH IS KEEPING LOW STATUS VERY NEAR THE TERMINALS. BELIEVE THAT CMX WILL STAY WITH BKN MVFR CIGS THROUGHOUT THE DAY...WHILE IWD SHOULD SCATTER OUT. AS FOR SAW...THEY HAVE SCATTERED OUT EARLY THIS AFTERNOON...BUT REDEVELOPMENT OF MVFR STRATOCUMULUS SHOULD COMMENCE BY MID-AFTERNOON. A MID-LEVEL RIDGE MOVING OVERHEAD TONIGHT WILL CLEAR OUT MID TO HIGH-LEVEL CLOUDS AND ALLOW FOR DECENT RADIATIONAL COOLING. IF LAST NIGHT IS ANY INDICATION OF HOW THINGS WILL GO TONIGHT...ALL SITES CAN BE EXPECTED TO REACH LANDING MINS BY AROUND 05Z. SAW COULD SEE THIS HAPPEN EARLIER GIVEN EXTRA MOISTURE AROUND FROM RAINFALL THIS MORNING. DO NOT SEE ANY REASON THINGS WILL CLEAR OUT TOO QUICK TUESDAY MORNING...SO HELD ON TO LOWER CIGS AND VIS UNTIL LATE MORNING AT ALL SITES. BY THE END OF THE PERIOD...MIXING SHOULD ERODE MUCH OF THE CLOUD COVER. THOUGH OUTSIDE OF THE PERIOD...IWD HAS THE POTENTIAL TO SEE SOME CONVECTION DEVELOP BY LATE AFTERNOON. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON JUL 8 2013 A DENSE FOG ADVISORY REMAINS TODAY FOR ALL OF LAKE SUPERIOR GIVEN SEVERAL SHIP REPORTS OF NEAR ZERO VISIBILITY AND VERY HUMID AIR OVER RELATIVELY CHILLY LAKE SUPERIOR WATERS. THE FOG MAY ALSO LINGER INTO TONIGHT BEFORE DISSIPATING TUESDAY. A SURFACE FRONT MOVING ACROSS LAKE SUPERIOR TUESDAY EVENING WILL ALLOW WINDS TO SHIFT TO THE NORTHWEST AT 15 TO 25 KNOTS FOR A SHORT TIME LATE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE WILL SETTLE BACK OVER THE LAKE FOR THE LATER HALF OF THE WEEK WITH WINDS LESS THAN 15 KNOTS EXPECTED INTO NEXT WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 11 AM EDT /10 AM CDT/ TUESDAY FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...KLUBER MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
754 AM EDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON JUL 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA. AT THE SFC...A FRONTAL BOUNDARY EXTENDED ACROSS NRN WI THROUGH SRN UPPER MI. A SHORTWAVE TROUGH FROM NRN ONTARIO THROUGH WRN LAKE SUPERIOR INTO NW WI SUPPORTED A LARGE AREA OF SHOWERS AND THUNDERSTORMS ACROSS CNTRL UPPER MI INTO NE WI AND NRN LAKE MICHIGAN. EVEN THOUGH THE GREATER MUCAPE VALUES OF 500-1000 J/KG AND STRONGER TSRA WERE LOCATED ALONG AND SOUTH OF THE FRONT...FORCING ASSOCIATED WITH THE SHRTWV WAS STRONG ENOUGH TO SUPPORT TSRA OVER N CNTRL UPPER MI. MANY LOCATIONS FROM GOGEBIC COUNTY THROUGH SRN UPPER MI HAVE RECEIVED RAINFALL AMOUNTS IN THE 1 TO 2 INCH RANGE...PER RADAR ESTIMATES. TODAY...EXPECT THAT AS THE SHRTWV MOVES OFF TO THE EAST THIS MORNING...THE SHRA/TSRA WILL ALSO SHIFT INTO THE ERN CWA. WITH SOME CLEARING IN THE AFTERNOON...TEMPS COULD AGAIN REBOUND TO THE LOWER 80S OVER THE SOUTH HALF OF UPPER MICHIGAN. EVEN THOUGH THIS WOULD BOOST MLCAPE VALUES BACK INTO THE 1K-2K J/KG RANGE...WITH MID LEVEL RIDGING AND WEAK QVECTOR DIV BUILDING INTO THE AREA IN THE WAKE OF THE SHORTWAVE....PCPN CHANCES WILL BE MINIMAL. NEVERTHELESS...SOME ISOLD SHRA/TSRA WILL STILL BE POSSIBLE...MAINLY OVER THE S CNTRL CWA WHERE MODELS SUGGEST A WEAK SFC TROUGH AXIS WOULD MAXIMIZE LOW LEVEL CONVERGENCE. TONIGHT...WEAK MID-LEVEL RIDGING SHOULD AND LOSS OF DAYTIME HEATING SHOULD BRING AN END TO ANY LINGERING PCPN. MID LEVEL DRYING AND A DEVELOPING SUBSIDENCE INVERSION ABOVE LINGERING LOW-LEVEL MOISTURE WILL FAVOR ANOTHER ROUND OF FOG ACROSS INTERIOR LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 508 AM EDT MON JUL 8 2013 THE MODELS CONTINUE TO AGREE ON THE GENERAL IDEA THAT AN MCS WILL BE ONGOING AT THE START OF THE PERIOD NEAR THE NOSE OF THE 40-45KT LLJ OVER THE UPPER MISSISSIPPI VALLEY. HOWEVER...THERE TENDS TO BE SOME MODEL DISAGREEMENT ON THE EXACT PLACEMENT OF THE MCS...WHICH WILL PROVE CRITICAL IN THE PRECIPITATION AND POP FORECAST ESPECIALLY TUESDAY AFTERNOON INTO TUESDAY EVENING. IN GENERAL...THE MODELS HAVE TRENDED NORTHWARD WITH THE NOSE OF THE LOW LEVEL JET. THE REGIONAL GEM IS THE MOST AGGRESSIVE...WITH THE BEST LOW LEVEL JET ENERGY FOCUSED WELL INTO NRN MN AND WESTERN LAKE SUPERIOR TUESDAY...WHILE THE NAM AND GFS SUPPRESS IT FURTHER SOUTH INTO CENTRAL WI AND SOUTH-CENTRAL UPPER MI RESPECTIVELY. DUE TO CONVECTIVE FEEDBACK FROM BOTH THE MODELS...IT IS UNCLEAR WHERE THIS MCS WILL TRACK ON TUESDAY...HOWEVER CLIMATOLOGY...PAST EXPERIENCE AND MODEL FORWARD PROPAGATING CORFIDI VECTORS WOULD SUGGEST THAT ANY MCS OVER SOUTHERN/CENTRAL MN TUE MORNING WOULD LIKELY STAY NEAR OR JUST SOUTH OF THE WI/MI BORDER AND PERHAPS CLIP MENOMINEE COUNTY LATER TUESDAY AFTERNOON. THIS SCENARIO WOULD POTENTIALLY LEAVE MUCH OF UPPER MICHIGAN DRY ON TUESDAY OR JUST WITH RESIDUAL STRATIFORM RAIN AND EMBEDDED THUNDER TUE AFTN INTO THE EVENING. IN ADDITION...THIS MCS MAY HELP DISRUPT THE MOISTURE INFLOW INTO THE MAIN SYSTEM AND COLD FRONT OVER THE NRN PLAINS/NW ONTARIO LATER TUESDAY INTO TUESDAY NIGHT. RESIDUAL CLOUD COVER BLOWOFF FROM THE MCS MAY ALSO ALLOW FOR DIMINISHED INSTABILITY ACROSS THE REGION AS THE COLD FRONT APPROACHES FROM THE NORTHWEST TUESDAY NIGHT. AS SUCH...AS PREVIOUS FORECASTS HAVE INDICATED...CONFIDENCE REMAINS RATHER LOW REGARDING THE POP/QPF FORECAST TUESDAY AFTERNOON INTO TUESDAY NIGHT. FOR NOW...HAVE MAINTAINED LIKELY POPS ACROSS THE SOUTH CENTRAL TUE AFTN WITH CHANCE POPS ELSEWHERE. FOR TUESDAY NIGHT...HAVE OPTED TO GO WITH LIKELY POPS NEAR LAKE MICHIGAN WITH CHANCE POPS ELSEWHERE AS THE MAIN UPPER WAVE AND ASSOCIATED COLD FRONT PASS THROUGH. MUCH LESS HUMID AND MORE SEASONABLE TEMPS ON WEDNESDAY BEHIND THE COLD FRONT. CANNOT RULE OUT A PASSING SHOWER EARLY ACROSS THE EASTERN HALF OF UPPER MI EARLY WED MORNING AS THE UPPER TROUGH AXIS WILL HAVE YET TO PASS THROUGH. OTHERWISE...HIGH PRESSURE WILL BUILD ACROSS THE AREA WED NIGHT-THURSDAY LEADING TO VERY SEASONABLE AND DRY CONDITIONS. UPPER HEIGHTS BUILD ON FRIDAY ACROSS THE WESTERN LAKES...GIVING SOME WARMER TEMPS BUT DRY CONDITIONS WILL CONTINUE. ON SATURDAY...THE GFS AND 00Z ECMWF ARE IN BETTER AGREEMENT IN SHOWING A WEAK DISTURBANCE MOVING OVER THE RIDGE AXIS. ALTHOUGH MOISTURE WILL BE LACKING...CANNOT TOTALLY RULE OUT SHOWERS/STORMS ACROSS THE WEST SAT AFTN AS AS SUCH HAVE ADDED A 30 PCT CHANCE ON SATURDAY. NEXT SYSTEM MOVES INTO THE WESTERN LAKES LATE IN THE WEEKEND OR EARLY MONDAY. STILL SOME TIMING ISSUES WITH THE ECMWF BEING FASTER THAN THE GFS. WITH THIS IN MIND...HAVE KEPT ANY MENTION OF PRECIPITATION OUT OF THE FORECAST FOR SUNDAY...BUT MAY NEED TO BE INTRODUCED IN LATER FORECASTS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 753 AM EDT MON JUL 8 2013 EXPECT LIFR/VLIFR CONDITIONS AT CMX/IWD WILL GRADUALLY IMPROVE THIS MORNING WITH DAYTIME HEATING/MIXING. AT SAW...WHERE RAIN HAS KEPT CONDITIONS FROM DROPPING OFF AS LOW...MAINLY IFR CONDITIONS WILL PERSIST INTO THIS AFTERNOON WITH PERSISTENT WEAK NE UPSLOPE FLOW. CIGS SHOULD ALSO LIFT TO MVFR/VFR BY MID AFTERNOON. MORE FOG/VLIFR CONDITIONS ARE EXPECTED TONIGHT WITH LINGERING LOW LEVEL MOISTURE... LIGHT WINDS/NOCTURNAL COOLING UNDER DRY AIR ALOFT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON JUL 8 2013 A DENSE FOG ADVISORY REMAINS TODAY FOR ALL OF LAKE SUPERIOR GIVEN SEVERAL SHIP REPORTS OF NEAR ZERO VISIBILITY AND VERY HUMID AIR OVER RELATIVELY CHILLY LAKE SUPERIOR WATERS. THE FOG MAY ALSO LINGER INTO TONIGHT BEFORE DISSIPATING TUESDAY. A SURFACE FRONT MOVING ACROSS LAKE SUPERIOR TUESDAY EVENING WILL ALLOW WINDS TO SHIFT TO THE NORTHWEST AT 15 TO 25 KNOTS FOR A SHORT TIME LATE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE WILL SETTLE BACK OVER THE LAKE FOR THE LATER HALF OF THE WEEK WITH WINDS LESS THAN 15 KNOTS EXPECTED INTO NEXT WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
511 AM EDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON JUL 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA. AT THE SFC...A FRONTAL BOUNDARY EXTENDED ACROSS NRN WI THROUGH SRN UPPER MI. A SHORTWAVE TROUGH FROM NRN ONTARIO THROUGH WRN LAKE SUPERIOR INTO NW WI SUPPORTED A LARGE AREA OF SHOWERS AND THUNDERSTORMS ACROSS CNTRL UPPER MI INTO NE WI AND NRN LAKE MICHIGAN. EVEN THOUGH THE GREATER MUCAPE VALUES OF 500-1000 J/KG AND STRONGER TSRA WERE LOCATED ALONG AND SOUTH OF THE FRONT...FORCING ASSOCIATED WITH THE SHRTWV WAS STRONG ENOUGH TO SUPPORT TSRA OVER N CNTRL UPPER MI. MANY LOCATIONS FROM GOGEBIC COUNTY THROUGH SRN UPPER MI HAVE RECEIVED RAINFALL AMOUNTS IN THE 1 TO 2 INCH RANGE...PER RADAR ESTIMATES. TODAY...EXPECT THAT AS THE SHRTWV MOVES OFF TO THE EAST THIS MORNING...THE SHRA/TSRA WILL ALSO SHIFT INTO THE ERN CWA. WITH SOME CLEARING IN THE AFTERNOON...TEMPS COULD AGAIN REBOUND TO THE LOWER 80S OVER THE SOUTH HALF OF UPPER MICHIGAN. EVEN THOUGH THIS WOULD BOOST MLCAPE VALUES BACK INTO THE 1K-2K J/KG RANGE...WITH MID LEVEL RIDGING AND WEAK QVECTOR DIV BUILDING INTO THE AREA IN THE WAKE OF THE SHORTWAVE....PCPN CHANCES WILL BE MINIMAL. NEVERTHELESS...SOME ISOLD SHRA/TSRA WILL STILL BE POSSIBLE...MAINLY OVER THE S CNTRL CWA WHERE MODELS SUGGEST A WEAK SFC TROUGH AXIS WOULD MAXIMIZE LOW LEVEL CONVERGENCE. TONIGHT...WEAK MID-LEVEL RIDGING SHOULD AND LOSS OF DAYTIME HEATING SHOULD BRING AN END TO ANY LINGERING PCPN. MID LEVEL DRYING AND A DEVELOPING SUBSIDENCE INVERSION ABOVE LINGERING LOW-LEVEL MOISTURE WILL FAVOR ANOTHER ROUND OF FOG ACROSS INTERIOR LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 508 AM EDT MON JUL 8 2013 THE MODELS CONTINUE TO AGREE ON THE GENERAL IDEA THAT AN MCS WILL BE ONGOING AT THE START OF THE PERIOD NEAR THE NOSE OF THE 40-45KT LLJ OVER THE UPPER MISSISSIPPI VALLEY. HOWEVER...THERE TENDS TO BE SOME MODEL DISAGREEMENT ON THE EXACT PLACEMENT OF THE MCS...WHICH WILL PROVE CRITICAL IN THE PRECIPITATION AND POP FORECAST ESPECIALLY TUESDAY AFTERNOON INTO TUESDAY EVENING. IN GENERAL...THE MODELS HAVE TRENDED NORTHWARD WITH THE NOSE OF THE LOW LEVEL JET. THE REGIONAL GEM IS THE MOST AGGRESSIVE...WITH THE BEST LOW LEVEL JET ENERGY FOCUSED WELL INTO NRN MN AND WESTERN LAKE SUPERIOR TUESDAY...WHILE THE NAM AND GFS SUPPRESS IT FURTHER SOUTH INTO CENTRAL WI AND SOUTH-CENTRAL UPPER MI RESPECTIVELY. DUE TO CONVECTIVE FEEDBACK FROM BOTH THE MODELS...IT IS UNCLEAR WHERE THIS MCS WILL TRACK ON TUESDAY...HOWEVER CLIMATOLOGY...PAST EXPERIENCE AND MODEL FORWARD PROPAGATING CORFIDI VECTORS WOULD SUGGEST THAT ANY MCS OVER SOUTHERN/CENTRAL MN TUE MORNING WOULD LIKELY STAY NEAR OR JUST SOUTH OF THE WI/MI BORDER AND PERHAPS CLIP MENOMINEE COUNTY LATER TUESDAY AFTERNOON. THIS SCENARIO WOULD POTENTIALLY LEAVE MUCH OF UPPER MICHIGAN DRY ON TUESDAY OR JUST WITH RESIDUAL STRATIFORM RAIN AND EMBEDDED THUNDER TUE AFTN INTO THE EVENING. IN ADDITION...THIS MCS MAY HELP DISRUPT THE MOISTURE INFLOW INTO THE MAIN SYSTEM AND COLD FRONT OVER THE NRN PLAINS/NW ONTARIO LATER TUESDAY INTO TUESDAY NIGHT. RESIDUAL CLOUD COVER BLOWOFF FROM THE MCS MAY ALSO ALLOW FOR DIMINISHED INSTABILITY ACROSS THE REGION AS THE COLD FRONT APPROACHES FROM THE NORTHWEST TUESDAY NIGHT. AS SUCH...AS PREVIOUS FORECASTS HAVE INDICATED...CONFIDENCE REMAINS RATHER LOW REGARDING THE POP/QPF FORECAST TUESDAY AFTERNOON INTO TUESDAY NIGHT. FOR NOW...HAVE MAINTAINED LIKELY POPS ACROSS THE SOUTH CENTRAL TUE AFTN WITH CHANCE POPS ELSEWHERE. FOR TUESDAY NIGHT...HAVE OPTED TO GO WITH LIKELY POPS NEAR LAKE MICHIGAN WITH CHANCE POPS ELSEWHERE AS THE MAIN UPPER WAVE AND ASSOCIATED COLD FRONT PASS THROUGH. MUCH LESS HUMID AND MORE SEASONABLE TEMPS ON WEDNESDAY BEHIND THE COLD FRONT. CANNOT RULE OUT A PASSING SHOWER EARLY ACROSS THE EASTERN HALF OF UPPER MI EARLY WED MORNING AS THE UPPER TROUGH AXIS WILL HAVE YET TO PASS THROUGH. OTHERWISE...HIGH PRESSURE WILL BUILD ACROSS THE AREA WED NIGHT-THURSDAY LEADING TO VERY SEASONABLE AND DRY CONDITIONS. UPPER HEIGHTS BUILD ON FRIDAY ACROSS THE WESTERN LAKES...GIVING SOME WARMER TEMPS BUT DRY CONDITIONS WILL CONTINUE. ON SATURDAY...THE GFS AND 00Z ECMWF ARE IN BETTER AGREEMENT IN SHOWING A WEAK DISTURBANCE MOVING OVER THE RIDGE AXIS. ALTHOUGH MOISTURE WILL BE LACKING...CANNOT TOTALLY RULE OUT SHOWERS/STORMS ACROSS THE WEST SAT AFTN AS AS SUCH HAVE ADDED A 30 PCT CHANCE ON SATURDAY. NEXT SYSTEM MOVES INTO THE WESTERN LAKES LATE IN THE WEEKEND OR EARLY MONDAY. STILL SOME TIMING ISSUES WITH THE ECMWF BEING FASTER THAN THE GFS. WITH THIS IN MIND...HAVE KEPT ANY MENTION OF PRECIPITATION OUT OF THE FORECAST FOR SUNDAY...BUT MAY NEED TO BE INTRODUCED IN LATER FORECASTS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 155 AM EDT MON JUL 8 2013 EXPECT LIFR/VLIFR CONDITIONS TO PERSIST AT CMX/SAW THRU SUNRISE WITH ENE FLOW OF MOIST AIR OFF LK SUP IN THE PRESENCE OF NOCTURNAL COOLING. THE FOG AND LO CLD HAS HAD A HARDER TIME MOVING INTO IWD... BUT STILL EXPECT FOG/LIFR CONDITIONS TO DVLP THERE WITH THE ARRIVAL OF DRIER AIR ALOFT EARLY THIS MRNG. WITH DAYTIME HEATING...THERE WL BE SLOW IMPROVEMENT LATER THIS MRNG/EARLY AFTN. THE BEST CHC FOR PERSISTENT LOWER CONDITIONS WL BE AT SAW WITH A MORE FAVORABLE UPSLOPE NE WIND COMPONENT. MORE FOG/IFR CONDITIONS ARE ON TAP FOR TNGT WITH LGT WINDS/NOCTURNAL COOLING UNDER DRY AIR ALOFT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON JUL 8 2013 A DENSE FOG ADVISORY REMAINS TODAY FOR ALL OF LAKE SUPERIOR GIVEN SEVERAL SHIP REPORTS OF NEAR ZERO VISIBILITY AND VERY HUMID AIR OVER RELATIVELY CHILLY LAKE SUPERIOR WATERS. THE FOG MAY ALSO LINGER INTO TONIGHT BEFORE DISSIPATING TUESDAY. A SURFACE FRONT MOVING ACROSS LAKE SUPERIOR TUESDAY EVENING WILL ALLOW WINDS TO SHIFT TO THE NORTHWEST AT 15 TO 25 KNOTS FOR A SHORT TIME LATE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE WILL SETTLE BACK OVER THE LAKE FOR THE LATER HALF OF THE WEEK WITH WINDS LESS THAN 15 KNOTS EXPECTED INTO NEXT WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
649 PM CDT TUE JUL 9 2013 .UPDATE... HAVE SENT OUT SOME UPDATES TO REFINE PRECIPITATION AND CLOUD TRENDS THIS EVENING. THE TROUGH AXIS SWEEPING ACROSS THE AREA NOW THAT IS ASSOCIATED WITH SOME SHOWERS/ISOLATED TSRA ARE VERY LIKELY THE TAIL END OF PRECIPITATION FOR THE EVENING...THOUGH CANNOT RULE OUT A FEW ISOLATED SHOWERS AS CAN BE SEEN BACK AROUND WASKISH. THIS TROUGH AXIS IS ALSO THE LEADING EDGE OF THE DRY AIR...WHERE DEWPOINTS GO FROM THE MID 60S AROUND HIBBING...DROPPING TO THE MID 50S BY BAUDETTE. && .AVIATION... LAST ROUND OF SHOWERS WITH SOME MVFR CIGS TO MOVE ACROSS TERMINALS. IT HAS ALREADY MOVED PAST KINL...AND IS EXPECTED TO AFFECT THE REMAINING TERMINALS BY 05Z TONIGHT. OTHERWISE EXPECT VFR CONDITIONS. WINDS TO PICK UP FOR A SHORT PERIOD BEHIND TROUGH AND GUST 15-18KTS FIR KHIB AND KBRD...BUT NOCTURNAL INVERSION SHOULD KEEP THE OTHER SITES FROM DOING THE SAME...AND WINDS SHOULD DROP OFF TO LESS THAN 10KTS AFTER 05Z. SKIES TO GRADUALLY CLEAR OVERNIGHT. AFTER 14Z WEDNESDAY WINDS TO INCREASE TO 10-15KTS WITH GUSTS TO 20KTS. VFR CONDITIONS EXPECTED WITH SOME DIURNAL CU WITH CIGS AOA 4KFT. && .PREV DISCUSSION... /ISSUED 314 PM CDT TUE JUL 9 2013/ SHORT TERM...THROUGH EARLY WEDNESDAY EVENING. COVERAGE OF SHOWERS AND STORMS HAVE DIMINISHED OVER MUCH OF THE NORTHLAND THIS AFTERNOON...WITH HIGHEST CONCENTRATION OVER OUR FAR EASTERN ZONES ALONG AND AHEAD OF THE LOW LEVEL BOUNDARY. ADDITIONAL ISOLATED SHOWERS WERE OCCURRING BEHIND THIS BOUNDARY WITH OTHERS ASSOCIATED WITH THE UPPER WAVE OVER SOUTHERN MANITOBA/NORTHERN NORTH DAKOTA. LATEST HRRR HAS A DECENT HANDLE ON CURRENT CONVECTION...AND SHOWS COVERAGE REMAINING LIMITED TONIGHT. WE DO HAVE POPS THIS EVENING OVER MUCH OF THE NORTHLAND...BUT DECREASE THEM FROM WEST TO EAST TONIGHT. THE THREAT FOR SEVERE STORMS IS LOW AS BEST CONVERGENCE SHOULD BE EXITING OUR CWA THIS EVENING...AND STABILITY AND SHEAR ARE NOT REAL SUPPORTIVE GIVEN THE AMOUNT OF LIFT. SOME FOG MAY LINGER THIS EVENING AROUND LAKE SUPERIOR...PARTICULARLY UP THE NORTH SHORE...BUT THEN THAT SHOULD DIMINISH OVERNIGHT AS WINDS TURN NORTHWEST BEHIND THE FRONT. WEDNESDAY SHOULD FEATURE PARTLY TO MOSTLY SUNNY SKIES WITH HIGH PRESSURE BUILDING IN. TEMPERATURES WILL BE IN THE SEVENTIES. WE DO EXPECT GOOD MIXING WITH STEEP LAPSE RATES. THIS WILL LEAD TO SOME GUSTY WINDS BY AFTERNOON. SOME STEEPER LAPSE RATES OVER THE ARROWHEAD AND IT`S PROXIMITY TO THE EXITING UPPER TROUGH SHOULD BE ENOUGH TO CAUSE SOME THICKER CLOUDS UP THERE BY WEDNESDAY AFTERNOON. WE LEFT THAT AREA DRY...BUT LATER SHIFTS WILL HAVE TO MONITOR FOR THE POSSIBLE ADDITION OF A FEW SHOWERS OR THUNDERSTORMS IN THE AFTERNOON. LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. A LARGE SFC HIGH AND ASSOCIATED UPPER RIDGE WILL BE BUILDING IN ACROSS THE UPPER MIDWEST WED NIGHT...ALONG WITH DRYING CONDITIONS AND MOSTLY CLEAR SKIES. RELATIVELY COOL TEMPS COULD DEVELOP EARLY THUR MORNING UNDER CALM WINDS AND STRONG RADIATIONAL COOLING. SHOULD SEE MOSTLY SUNNY SKIES ON THURSDAY WITH HIGHS IN THE 70S AROUND THE LAKE AND 80S INLAND. THUR NIGHT SHOULD REMAIN MOSTLY CLEAR WITH HIGH PRESSURE IN PLACE. HOWEVER...AS THE SFC HIGH SHIFTS EWD...A RETURN SLY FLOW WILL DEVELOP AND BEGIN TO USHER IN MORE CLOUD COVER AND A RICHER MORE UNSTABLE AIR MASS AHEAD OF THE NEXT SFC TROUGH/COLD FRONT EXPECTED TO MOVE INTO THE REGION THIS WEEKEND. FRIDAY WILL BE A TRANSITION DAY WITH CLOUDS INCREASING FROM THE W...BUT MINIMAL PRECIP CHANCES UNTIL LATER FRI NIGHT. MODEL GUIDANCE IS INDICATING THAT THE SFC FRONT WILL STALL OUT ACROSS NRN MN/WRN LAKE SUPERIOR ALONG THE NRN/NWRN FRINGES OF AN ELONGATED RIDGE SITUATED OVER THE MID MS VALLEY/SRN GREAT LAKES REGION. THIS PATTERN WOULD ALLOW FOR A PROLONGED PERIOD OF SHOWERS AND STORMS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...WITH POTENTIALLY PERIODS OF HEAVY RAIN. WILL NEED TO MONITOR THIS PATTERN AND ANY CHANGES DURING THE NEXT COUPLE DAYS. COULD BE DEALING WITH HYDRO ISSUES SAT THROUGH MON. OTHERWISE...TEMPERATURES REMAIN VERY SEASONAL...WITH HIGHS IN THE 70S AND LOWER 80S AND LOWS IN THE 50S AND LOWER 60S. AVIATION...18Z TAF ISSUANCE. WIDESPREAD RAIN SHOWERS WITH AFTERNOON EMBEDDED THUNDERSTORMS ARE EXPECTED THE REST OF TODAY BEFORE THE MAIN SFC FRONT PUSHES THROUGH EARLY THIS EVENING AND ALLOWS CONDITIONS TO DRY OUT LATE TONIGHT AND TOMORROW. A FEW OF THE STORMS THIS AFTERNOON COULD PRODUCE HAIL AND VERY STRONG WIND GUSTS. DENSE FOG SHOULD REMAIN CONFINED TO LAKE SUPERIOR AND THE IMMEDIATE LATE SHORE THROUGH 21Z...AND NOT HAVE TOO MUCH OF AN IMPACT ON THE DLH TERMINAL. WINDS SHIFT TO THE NW QUICKLY BEHIND THE FRONT TONIGHT AND BECOME GUSTY WED MORNING. && .POINT TEMPS/POPS... DLH 54 77 56 79 / 30 0 0 0 INL 53 76 55 82 / 10 10 0 0 BRD 56 78 55 82 / 10 0 0 0 HYR 56 78 52 81 / 40 0 0 0 ASX 54 76 51 79 / 50 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...LE AVIATION...NONE
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
559 PM CDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 318 PM CDT TUE JUL 9 2013 A HOT AND HUMID AFTERNOON WAS IN PROGRESS ACROSS THE REGION AS UPPER LEVEL HIGH PRESSURE REMAINED CENTERED ACROSS THE DESERT SOUTHWEST AND SOUTHERN PLAINS. TEMPERATURES WERE IN THE LOWER TO MIDDLE 90S AREA-WIDE...WITH DEW POINTS RANGING FROM THE MIDDLE 60S AROUND BRANSON TO THE MIDDLE 70S UP IN THE ROLLA AREA. HEAT INDICES IN THE 100 TO 105 DEGREE RANGE WERE BEING OBSERVED FROM THE INTERSTATE 49 CORRIDOR ON INTO THE TRUMAN LAKE REGION. THIS JIVES QUITE NICELY WITH THE CURRENT HEAT ADVISORY. HEAT INDICES ACROSS THE REMAINDER OF THE MISSOURI OZARKS WERE IN THE MIDDLE 90S TO AROUND 100 DEGREES. AS OF 3 PM...THERE WERE NO NOTEWORTHY RADAR RETURNS TO SPEAK OF...WITH AN ESTABLISHED CUMULUS FIELD ALONG AND EAST OF A TRUMAN TO TABLE ROCK LAKE LINE. VERTICAL GROWTH HAS BEEN STYMIED BY A CAPPING INVERSION UP TO THIS POINT. && .SHORT TERM...(LATE THIS AFTERNOON THROUGH WEDNESDAY) ISSUED AT 318 PM CDT TUE JUL 9 2013 WE WILL HAVE TO WATCH FOR AN UPDRAFT OR TWO LATE THIS AFTERNOON ACROSS THE EASTERN MISSOURI OZARKS AS A WEAK UPPER LEVEL TROUGH AXIS CLIPS THE REGION. OTHERWISE...MAINLY DRY WEATHER IS EXPECTED FOR THE EARLY TO MID EVENING HOURS. MEANWHILE...THUNDERSTORM DEVELOPMENT IS ANTICIPATED THROUGHOUT THE EVENING INTO THE OVERNIGHT PERIOD ACROSS NORTHERN KANSAS AND MISSOURI. AT THIS POINT...WE EXPECT ENOUGH COVERAGE/COLD POOL CONGLOMERATION TO FORM A LOOSE MCS OR TWO. UPWIND PROPAGATING CORFIDI VECTORS WOULD SUPPORT THIS ACTIVITY MAKING IT INTO CENTRAL MISSOURI LATE TONIGHT. AT THIS TIME...WE BELIEVE THIS ACTIVITY WILL BE SUB-SEVERE AS IT WOULD BE OUTFLOW DOMINANT AND OUTRUNNING BETTER INSTABILITY. OTHERWISE...WE ARE LOOKING AT A WARM AND MUGGY NIGHT WITH PORTIONS OF WESTERN MISSOURI ONLY FALLING INTO THE UPPER 70S FOR LOWS. THE FORECAST FOR WEDNESDAY THEN BECOMES HIGHLY DEPENDENT ON WHAT OCCURS OVERNIGHT WITH RESPECT TO MCS ACTIVITY. THERE SEEMS TO BE A FAIRLY GOOD SIGNAL THAT AT THE VERY LEAST...CONVECTIVE OUTFLOW WILL PUSH SOUTH TOWARDS THE HIGHWAY 60 CORRIDOR. ADDITIONALLY...A SYNOPTIC SCALE COLD FRONT WILL SLOWLY SAG SOUTH INTO CENTRAL AND EVENTUALLY SOUTHERN MISSOURI ON WEDNESDAY AS SHORT WAVE ENERGY TRACKS ACROSS THE GREAT LAKES REGION. BOTH OF THESE FEATURES...ALONG WITH ANY LEFTOVER CONVECTION AND/OR CLOUD DEBRIS WILL HAVE AN IMPACT ON TEMPERATURES WEDNESDAY. INTERESTINGLY...850 MB TEMPERATURES SHOULD BE 2 TO 3 DEGREES WARMER ON WEDNESDAY THAN THOSE OF TODAY. AT THIS TIME...WE ARE GOING ON THE WARM SIDE OF GUIDANCE...ESPECIALLY ACROSS SOUTHERN MISSOURI. AREAS ALONG AND SOUTH OF HIGHWAY 60 MAY VERY WELL SEE MIDDLE TO UPPER 90S FOR HIGHS. WE BELIEVE THAT THERE IS A FAIRLY GOOD PROBABILITY THAT LOW LEVEL MOISTURE POOLING WILL OCCUR SOUTH OF ONE OR BOTH OF THESE SURFACE FEATURES. THIS WOULD RESULT IN DEW POINTS RISING INTO THE LOWER TO MIDDLE 70S. RESULTING HEAT INDICES MAY AGAIN APPROACH OR EXCEED HEAT ADVISORY CRITERIA... 105 DEGREES...OVER SOUTHERN MISSOURI. WITH SOME QUESTION REMAINING REGARDING THE EVENTUAL PLACEMENT OF CONVECTIVE OUTFLOW AND THE FRONT...WE WILL DEFER TO THE OVERNIGHT SHIFT ON WHETHER OR NOT AN ADVISORY IS REQUIRED FOR WEDNESDAY. ANOTHER ITEM WE WILL BE WATCHING CLOSELY FOR WEDNESDAY AFTERNOON AND EVENING IS THE POTENTIAL FOR SEVERE STORMS. A VERY HIGH LOW LEVEL THETA-E AIRMASS WILL BE IN PLACE ACROSS SOUTHEASTERN KANSAS AND SOUTHERN MISSOURI. THIS WILL RESULT IN EXTREME INSTABILITY...WITH MLCAPE VALUES GETTING INTO THE 3000 TO 4000 J/KG RANGE NEAR THE FRONTAL BOUNDARY. SCATTERED THUNDERSTORM INITIATION IS ANTICIPATED AT THIS POINT EITHER ALONG THE SURFACE FRONT...OR PERHAPS CLOSER TO THE 850 MB FRONT. WE WILL ALSO HAVE TO WATCH FOR INITIATION ALONG ANY REMAINING OUTFLOW BOUNDARIES. GIVEN THE EXTREME INSTABILITY AND LOW LEVEL THETA-E DIFFERENTIALS LIKELY EXCEEDING 30 KELVIN...WE ARE CONCERNED WITH A SEVERE WIND THREAT. THE THREAT MAY INITIALLY BE MORE OF A HYBRID MICROBURST VARIETY. IF ENOUGH UPDRAFTS DEVELOP...WE MAY THEN BE DEALING WITH MULTICELLULAR BEHAVIOR WITH A MORE WIDESPREAD WIND DAMAGE THREAT. WE MAY ALSO SEE A FEW SEVERE HAILERS DESPITE HIGH FREEZING LEVELS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 318 PM CDT TUE JUL 9 2013 THE MAIN THUNDERSTORM THREAT SHOULD BEGIN TO DIMINISH LATE WEDNESDAY EVENING AS INSTABILITY DECREASES. WHILE THE SURFACE FRONT SHOULD CLEAR THE MISSOURI OZARKS TO THE SOUTH AND WEST...MODELS ARE INDICATING THAT THE 850 FRONT MAY HANG UP FROM NORTHEASTERN KANSAS DOWN INTO WESTERN ARKANSAS. THUS...A SLIGHT CHANCE FOR THUNDERSTORMS WILL REMAIN OVERNIGHT AND INTO THURSDAY ACROSS PORTIONS OF EXTREME SOUTHEASTERN KANSAS AND FAR SOUTHWESTERN MISSOURI. THE GOOD NEWS IS THAT TEMPERATURES AND DEW POINTS WILL BE NOTICEABLY COOLER FROM THURSDAY INTO THE UPCOMING WEEKEND. GENERALLY SPEAKING... TEMPERATURES WILL BE FAIRLY CLOSE TO NORMAL FOR THIS TIME OF YEAR. WE ARE THEN LOOKING AT A SLOW WARMING TREND AS WE GET INTO THE BEGINNING OF NEXT WEEK AS THAT UPPER LEVEL RIDGE BEGINS TO STRENGTHEN AND FOLD OVER INTO THE CENTRAL UNITED STATES. THERE MAY BE A LOW POTENTIAL FOR AFTERNOON PULSERS DEPENDING ON THE ACTUAL POSITION OF THE UPPER LEVEL RIDGE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 557 PM CDT TUE JUL 9 2013 WILL BE WATCHING THE DEVELOPING THUNDERSTORM COMPLEX TO THE WEST IN KANSAS THIS EVENING FOR TIMING INTO THE CWA. HRRR BRINGS THIS IN AFTER 08Z AND WILL GO CLOSE TO THAT FOR INITIAL TIMING. HAVE CARRIED A PROB30 AFTER 09Z AT SGF/JLN FOR THE ONSET OF ANY CONVECITON. VFR CONDITIONS EXPECTED OUTSIDE OF THE CONVECTION WITH MVFR CONDITIONS DURING CONVECTION. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MOZ055-066-067-077- 078-088-093. KS...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ073-097-101. && $$ SYNOPSIS...SCHAUMANN SHORT TERM...SCHAUMANN LONG TERM...SCHAUMANN AVIATION...LINDENBERG
AREA FORECAST DISCUSSION
NWS GLASGOW MT
430 PM MDT MON JUL 8 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY... 430PM UPDATE... SEVERE THUNDERSTORM WATCH WAS JUST EXTENDED TO INCLUDE DANIELS AND SHERIDAN COUNTIES UNTIL 7PM. FORECAST APPEARS ON TRACK SO NO OTHER CHANGES AT THIS TIME. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PUSH FROM WEST TO EAST ACROSS THE CWA THIS EVENING AND TONIGHT. SOME STORMS WILL PRODUCE LOCALLY HEAVY RAINFALL...VERY LARGE HAIL...AND STRONG WINDS. REPORTS OF GOLF BALL TO BASEBALL SIZED HAIL HAVE COME IN THIS EVENING WITH A STORM THAT PUSHED THROUGH NORTHEASTERN GARFIELD COUNTY AND INTO SOUTHERN MCCONE COUNTY. THIS STORM IS CURRENTLY THE STRONGEST STORM IN THE FORECAST REGION AND WILL BE MOVING SOUTHEAST INTO SOUTHERN DAWSON AND NORTHERN PRAIRIE COUNTIES. ADDITIONAL SHOWERS AND STORMS EXIST IN A LINE FROM JUST WEST OF THE PORT OF OPHEIM EXTENDING DOWN THROUGH PETROLEUM COUNTY. SOME OF THESE STORMS MAY BECOME SEVERE AS WELL AS THEY MARCH EASTWARD THROUGH THE EVENING. WILL UPDATE AS NEEDED. MALIAWCO MAIN FOCUS FOR THE SHORT TERM PERIOD IS A STRONG UPPER LEVEL SHORTWAVE FEATURE PUSHING INTO WESTERN MONTANA THIS AFTERNOON. OUT AHEAD OF THIS WAVE THERE IS ENOUGH INSTABILITY TO GENERATE SOME SHOWERS AND THUNDERSTORMS. FORECAST SOUNDINGS SHOW VERY GOOD CAPE/DIRECTIONAL WIND SHEAR PROFILES THROUGH TONIGHT AND PRECIPITABLE WATER VALUES OF GREATER THAN ONE INCH. ALSO GIVEN SEVERE THUNDERSTORM WATCH UNTIL 7PM FOR MOST OF THE CWA EXCEPT FOR DANIELS AND SHERIDAN COUNTIES...WILL NEED TO MONITOR FOR SOME STORMS TO PRODUCE LARGE HAIL...STRONG WINDS...AND VERY HEAVY RAINFALL. SPC STORM SCALE ENSEMBLE OF OPPORTUNITY PRODUCT SHOWS CONSISTENCY WITH LATEST HRRR AND NAM MODEL SOLUTIONS. EXPECT MOST OF THE ACTIVITY TO OCCUR PRIOR TO MIDNIGHT. BEYOND MIDNIGHT...CANNOT RULE OUT SHOWERS AND STORMS BUT THEY SHOULD REDUCE IN COVERAGE AND SEVERE POTENTIAL WILL LIKELY BE LIMITED BY THAT TIME. TUESDAY AND WEDNESDAY...ANY LEFTOVER SHOWERS AND THUNDERSTORMS WILL EXIT THE CWA DURING THE MORNING HOURS ON TUESDAY. THEREAFTER...MODELS DEPICT AN UPPER LEVEL RIDGE BUILDING INTO THE CWA WHICH WILL LEAD TO AN ABUNDANCE OF SUNSHINE...DRIER CONDITIONS...AND WARMING TEMPERATURES UNDER A REGIME OF LARGE SCALE SUBSIDENCE. DID NOT MAKE MANY CHANGES TO THIS PORTION OF THE FORECAST DUE TO THE PRIMARY CONCENTRATION ON THE SEVERE WEATHER POTENTIAL FOR THIS AFTERNOON INTO TONIGHT. WILL MAKE UPDATES AS NEEDED AS CONDITIONS WARRENT. MALIAWCO .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... SYNOPTIC SET UP... LONG TERM BEGINS WITH A LARGE HEAT DOME OVER THE DESERT SOUTHWEST AND INTERMOUNTAIN WEST. A RIDGE SPUR IS ANTICIPATED TO JUT OUT OF THE DOME OVER THE HIGH PLAINS OF MONTANA AND ALBERTA. A CLOSED LOW IS EXPECTED OVER THE COAST OF BRITISH COLUMBIA AND THE PACIFIC NORTHWEST. WEDNESDAY NIGHT INTO THURSDAY... DRY CONDITIONS ARE ANTICIPATED UNTIL THURSDAY AS NORTHEAST MONTANA COMES UNDER THE FULL OF AND INCREASING RIDGE. THURSDAY... THE AXIS OF THE RIDGE WILL PASS THROUGH AND ALLOW FOR A ISOLATED THUNDERSTORMS TO DEVELOP ON THE AXIS. THURSDAY ALSO LOOKS TO BE VERY WARM AHEAD OF THE AXIS WITH UPPER 90S AND POSSIBLE AS 850 MB TEMPERATURES REACH INTO THE 30* CELSIUS RANGE. THURSDAY NIGHT INTO SATURDAY...CLOSED LOW OVER THE PACIFIC NORTHWEST IS ANTICIPATED TO MOVE EAST THROUGH WEST MONTANA INTO THE HIGH PLAINS... EXITING THE RIDGE ALOFT OVER THE GREAT PLAINS. THIS WILL PLACE NORTHEAST MONTANA IN A SOUTHWEST FLOW WITH A WEAK TROUGHS AND SHORTWAVES MOVING THROUGH THE FLOW. A SHORTWAVE IS CURRENTLY TIMED ON FRIDAY WITH THE BASE OF THE LARGE TROUGH MOVING THROUGH SATURDAY HOWEVER... TIMING OF THESE WAVES COULD EASILY SHIFT AS THE LAST COUPLE RUNS HAVE ALREADY MOVED THEM AROUND. SATURDAY NIGHT ONWARD... THE TROUGH IS ANTICIPATED TO PASS OFF TO THE EAST AND REPRESS THE HEAT TO THE SOUTH WHILE A NEW RIDGE BUILDS OVER THE PACIFIC NORTHWEST. THIS WILL GENERATE ZONAL TO NORTHWEST FLOW ACROSS NORTHEAST MONTANA. CONDITIONS WILL BE DRY SLIGHTLY WITH A WEAK WARMING TREND. GAH && .AVIATION... VFR. ISOLATED THUNDERSTORMS CAN BE EXPECTED OFF AND ON THROUGH THE DAY WITH FEW SIGNIFICANT IMPACTS THROUGH 18Z. 21Z-06Z...HOWEVER A LINE OR COMPLEX OF SEVERE THUNDERSTORMS IS EXPECTED TO ROLL ACROSS NORTHEAST MONTANA. 23-01Z FOR KGGW... 00Z-02Z FOR KOLF... AND 01-03Z FOR KSDY/KGDV BASED ON THE CURRENT GUIDANCE. DO EXPECT SIGNIFICANT IMPACTS TO FLIGHT OPERATIONS LATE THIS AFTERNOON AND THROUGH THE EVENING HOURS WITH THESE THUNDERSTORMS. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
234 PM MDT MON JUL 8 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY... MAIN FOCUS FOR THE SHORT TERM PERIOD IS A STRONG UPPER LEVEL SHORTWAVE FEATURE PUSHING INTO WESTERN MONTANA THIS AFTERNOON. OUT AHEAD OF THIS WAVE THERE IS ENOUGH INSTABILITY TO GENERATE SOME SHOWERS AND THUNDERSTORMS. FORECAST SOUNDINGS SHOW VERY GOOD CAPE/DIRECTIONAL WIND SHEAR PROFILES THROUGH TONIGHT AND PRECIPITABLE WATER VALUES OF GREATER THAN ONE INCH. ALSO GIVEN SEVERE THUNDERSTORM WATCH UNTIL 7PM FOR MOST OF THE CWA EXCEPT FOR DANIELS AND SHERIDAN COUNTIES...WILL NEED TO MONITOR FOR SOME STORMS TO PRODUCE LARGE HAIL...STRONG WINDS...AND VERY HEAVY RAINFALL. SPC STORM SCALE ENSEMBLE OF OPPORTUNITY PRODUCT SHOWS CONSISTENCY WITH LATEST HRRR AND NAM MODEL SOLUTIONS. EXPECT MOST OF THE ACTIVITY TO OCCUR PRIOR TO MIDNIGHT. BEYOND MIDNIGHT...CANNOT RULE OUT SHOWERS AND STORMS BUT THEY SHOULD REDUCE IN COVERAGE AND SEVERE POTENTIAL WILL LIKELY BE LIMITED BY THAT TIME. TUESDAY AND WEDNESDAY...ANY LEFTOVER SHOWERS AND THUNDERSTORMS WILL EXIT THE CWA DURING THE MORNING HOURS ON TUESDAY. THEREAFTER...MODELS DEPICT AN UPPER LEVEL RIDGE BUILDING INTO THE CWA WHICH WILL LEAD TO AN ABUNDANCE OF SUNSHINE...DRIER CONDITIONS...AND WARMING TEMPERATURES UNDER A REGIME OF LARGE SCALE SUBSIDENCE. DID NOT MAKE MANY CHANGES TO THIS PORTION OF THE FORECAST DUE TO THE PRIMARY CONCENTRATION ON THE SEVERE WEATHER POTENTIAL FOR THIS AFTERNOON INTO TONIGHT. WILL MAKE UPDATES AS NEEDED AS CONDITIONS WARRENT. MALIAWCO .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... SYNOPTIC SET UP... LONG TERM BEGINS WITH A LARGE HEAT DOME OVER THE DESERT SOUTHWEST AND INTERMOUNTAIN WEST. A RIDGE SPUR IS ANTICIPATED TO JUT OUT OF THE DOME OVER THE HIGH PLAINS OF MONTANA AND ALBERTA. A CLOSED LOW IS EXPECTED OVER THE COAST OF BRITISH COLUMBIA AND THE PACIFIC NORTHWEST. WEDNESDAY NIGHT INTO THURSDAY... DRY CONDITIONS ARE ANTICIPATED UNTIL THURSDAY AS NORTHEAST MONTANA COMES UNDER THE FULL OF AND INCREASING RIDGE. THURSDAY... THE AXIS OF THE RIDGE WILL PASS THROUGH AND ALLOW FOR A ISOLATED THUNDERSTORMS TO DEVELOP ON THE AXIS. THURSDAY ALSO LOOKS TO BE VERY WARM AHEAD OF THE AXIS WITH UPPER 90S AND POSSIBLE AS 850 MB TEMPERATURES REACH INTO THE 30* CELSIUS RANGE. THURSDAY NIGHT INTO SATURDAY...CLOSED LOW OVER THE PACIFIC NORTHWEST IS ANTICIPATED TO MOVE EAST THROUGH WEST MONTANA INTO THE HIGH PLAINS... EXITING THE RIDGE ALOFT OVER THE GREAT PLAINS. THIS WILL PLACE NORTHEAST MONTANA IN A SOUTHWEST FLOW WITH A WEAK TROUGHS AND SHORTWAVES MOVING THROUGH THE FLOW. A SHORTWAVE IS CURRENTLY TIMED ON FRIDAY WITH THE BASE OF THE LARGE TROUGH MOVING THROUGH SATURDAY HOWEVER... TIMING OF THESE WAVES COULD EASILY SHIFT AS THE LAST COUPLE RUNS HAVE ALREADY MOVED THEM AROUND. SATURDAY NIGHT ONWARD... THE TROUGH IS ANTICIPATED TO PASS OFF TO THE EAST AND REPRESS THE HEAT TO THE SOUTH WHILE A NEW RIDGE BUILDS OVER THE PACIFIC NORTHWEST. THIS WILL GENERATE ZONAL TO NORTHWEST FLOW ACROSS NORTHEAST MONTANA. CONDITIONS WILL BE DRY SLIGHTLY WITH A WEAK WARMING TREND. GAH && .AVIATION... VFR. ISOLATED THUNDERSTORMS CAN BE EXPECTED OFF AND ON THROUGH THE DAY WITH FEW SIGNIFICANT IMPACTS THROUGH 18Z. 21Z-06Z...HOWEVER A LINE OR COMPLEX OF SEVERE THUNDERSTORMS IS EXPECTED TO ROLL ACROSS NORTHEAST MONTANA. 23-01Z FOR KGGW... 00Z-02Z FOR KOLF... AND 01-03Z FOR KSDY/KGDV BASED ON THE CURRENT GUIDANCE. DO EXPECT SIGNIFICANT IMPACTS TO FLIGHT OPERATIONS LATE THIS AFTERNOON AND THROUGH THE EVENING HOURS WITH THESE THUNDERSTORMS. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1053 PM MDT SUN JUL 7 2013 .UPDATE... ISSUED UPDATE TO ZONES TO REMOVE REMAINING SEVERE THUNDERSTORM WATCH. ADJUSTED POPS FOR REMAINDER OF NIGHT AS WELL. BT && .SHORT TERM...VALID FOR MON AND TUE... MAIN FORECAST ISSUE IS SEVERE WX POTENTIAL THIS AFTERNOON/EVENING AND AGAIN TOMORROW. WATER VAPOR IMAGERY SHOWS WSW FLOW ALOFT WITH SHORTWAVE ENERGY APPROACHING FROM THE GREAT BASIN. A STRONGER TROF CAN BE SEEN ALONG THE PAC NW COAST...AND THIS FEATURE WILL BE A PLAYER FOR US MONDAY AND MONDAY NIGHT. PWATS IN PLACE ARE QUITE HIGH AND IN THE VICINITY OF AN INCH...PERHAPS A BIT HIGHER IN OUR EAST. LOW LEVEL E-SE WINDS ARE INCREASING...PROVIDING GREATER SHEAR AND LOW LEVEL MOISTURE THAN WE SAW ON SATURDAY...AND LATEST 850MB ANALYSIS SUGGESTS NOSE OF 850MB DEWPTS TO +13C IN FAR SE MT. WE REMAIN UNDER RRQ OF 60KT H3 JET TO OUR NORTH...THUS MODEST SYNOPTIC ASCENT IS PRESENT. OVERALL INGREDIENTS ARE IN PLACE FOR SEVERE WEATHER LATE THIS AFTN AND EVENING. RECENT HRRR RUNS AGREE WITH THIS ASSESSMENT AND HAVE BEEN CONSISTENT. CONVECTION BEGINNING TO INITIATE OVER OUR SW MTNS WITH A FEW LIGHTNING STRIKES NOTED SOUTH OF LIVINGSTON. A LONE CELL HAS EMERGED FROM THE CU FIELD SE OF BROADUS. WILL BE INTERESTING TO SEE WHAT SERN CELL WILL DO OVER THE NEXT COUPLE HOURS...SFC TEMPS NEAR THE MID 80S MAY BE ENOUGH TO BREAK CAP THAT HAS BEEN IN PLACE. OTHERWISE FOCUS SHOULD BE IN OUR WEST AS ACTIVITY SPREADS OFF THE HIGH TERRAIN...SHIFTING EAST OVER TIME. GREATEST SEVERE POTENTIAL THIS AFTN AND EVENING WILL BE EAST OF BILLINGS IN REGION OF GREATER INSTABILITY AND SHEAR...ESPECIALLY AS LOW LEVEL JET KICKS IN THIS EVENING. FOR MONDAY...OUR ENTIRE AREA WILL BE AT AN ELEVATED RISK FOR SEVERE STORMS DUE TO COMBINATION OF ASCENT FROM PAC NW TROF AND SURFACE COLD FRONT. LARGE HAIL AND DAMAGING WINDS MAIN THREATS. HEAVY RAIN WILL CONTINUE TO BE A POSSIBILITY BOTH TODAY AND TOMORROW DUE TO THE MOISTURE RICH AIRMASS IN PLACE. PASSAGE OF TROF...SURGE OF DRIER AIR AND SHIFT TO NW FLOW ALOFT WILL SIGNAL THE BEGINNINGS OF A PATTERN SHIFT ON TUESDAY...AS THE MOIST AIRMASS FINALLY GETS CLEANED OUT. COULD BE SOME MORNING SHOWERS ON TUESDAY ALONG PV MAX...BUT OTHERWISE EXPECT DRIER AND MORE STABLE CONDITIONS AS COOLER SFC RIDGE BUILDS IN FROM THE NW. HAVE LOWERED POPS TUESDAY AFTERNOON AND NIGHT. AS FOR TEMPS...MONDAY WILL BE THE WARMER OF THE NEXT TWO DAYS... WITH PREFRONTAL CONDITIONS PERHAPS ALLOWING FOR TEMPS NEAR 90F. TUESDAY WILL BE POSTFRONTAL AND COOLER WITH UPPER 70S TO MID 80S FOR HIGHS...OR A LITTLE BELOW NORMAL. JKL .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... MINIMAL CHANGES TO THE EXTENDED PERIOD...DUE IN LARGE PART TO MODEL INCONSISTENCY FOR LATTER PORTIONS OF THE PERIOD. THE PERIOD BEGINS WED UNDER AN UPPER LEVEL RIDGE...SO EXPECT HOT AND MAINLY DRY CONDITIONS. MODELS DO SHOW SOME SHORTWAVE ACTIVITY ROUNDING THE RIDGE...WITH SE LOW LEVEL FLOW OVER SOUTHEAST MONTANA LATE WED AFTN/EVE...SO I KEPT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST ACROSS THE SE. RIDGING DOMINATES THROUGH MUCH OF THE DAY THURS...SO HOT AND DRY CONDITIONS WILL AGAIN BE THE RULE. A WEAK COLD FRONT...ALONG WITH SHORTWAVE ACTIVITY...WILL MOVE ACROSS THE REGION THURS NIGHT...SO WE MAY SEE SOME CONVECTIVE ACTIVITY THURS EVE/NIGHT OVER THE WESTERN MOUNTAINS...AND OVER THE EAST...WHERE SHEAR IS BETTER AND THE ATMOSPHERE IS LESS CAPPED. FRI LOOKS TO BE A TAD COOLER BEHIND THE FRONT...BUT STILL QUITE WARM. MODEL SOLUTIONS DIVERGE SAT AND SUN. THE ECMWF BRINGS ANOTHER COLD FRONT THROUGH THE REGION SAT AND KEEP THE REGION UNDER THE INFLUENCE OF A WEAK UPPER LEVEL TROF SUN. MEANWHILE...THE GFS KEEPS THE AREA MAINLY UNDER THE INFLUENCE OF SOUTHWESTERLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE. BECAUSE OF THE LARGE MODEL DIFFERENCES...I LEFT THE FORECAST FROM SAT TO THE END OF THE EXTENDED PRETTY MUCH AS I INHERITED IT. TEMPS WED AND THURS LOOK TO BE IN THE MID 80S TO MID 90S...WITH SLIGHTLY COOLER WEATHER FRI. NOT QUITE SURE WHAT TEMPS WILL BE SAT AND SUN. IF THE GFS IS CORRECT...UPPER 80S TO 90S. IF THE ECMWF IS CORRECT...UPPER 70S TO MID 80S. FOR NOW...KEPT SAT AND SUN TEMPS IN THE MID 80S TO AROUND 90...SORT OF A BLEND OF THE GFS AND ECMWF. STC && .AVIATION... CONVECTIVE ACTIVITY WILL DIMINISH THROUGH MIDNIGHT WITH JUST AN ISOLATED SHOWER OR THUNDERSTORM AFTER MIDNIGHT IN MOST AREAS. STRONG WIND GUSTS AND MVFR TO IFR CONDITIONS IN HEAVY RAIN ARE THE MAIN THREATS FROM STORMS TONIGHT. OUTSIDE OF STORMS EXPECT VFR CONDITIONS. LOCAL AREAS OF FOG ARE POSSIBLE EARLY MONDAY MORNING IN AREAS THAT SAW HEAVY RAIN THIS EVENING...BUT SO FAR THIS DOESN`T INCLUDE AREA TAF LOCATIONS. CHAMBERS && .PRELIMINARY POINT TEMP/POPS... MON TUE WED THU FRI SAT SUN ----------------------------------------------------------- BIL 062/089 061/084 059/091 064/094 064/090 061/091 060/089 33/T 32/T 11/U 11/B 22/T 22/T 22/T LVM 053/088 050/085 048/091 056/094 052/090 051/091 050/089 53/T 31/B 11/U 11/B 22/T 22/T 22/T HDN 060/091 061/085 056/092 064/095 064/091 061/092 060/090 23/T 32/T 11/U 11/B 22/T 22/T 22/T MLS 065/088 062/084 059/092 066/095 063/090 062/091 061/089 34/T 53/T 11/U 12/T 22/T 22/T 22/T 4BQ 061/090 060/084 056/090 062/093 063/089 061/090 060/088 33/T 43/T 11/U 12/T 22/T 22/T 33/T BHK 060/084 060/079 055/086 061/089 063/085 062/086 061/084 44/T 54/T 12/T 22/T 22/T 22/T 33/T SHR 056/090 056/083 052/089 059/093 058/089 056/090 055/088 23/T 32/T 11/U 11/U 22/T 22/T 22/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
504 PM CDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 455 PM CDT MON JUL 8 2013 PLENTY OF THINGS TO PONDER DURING THE NEXT 24 HOURS...INCLUDING AT LEAST ONE CONDITIONAL RISK FOR SEVERE STORMS THIS EVENING...AND MAYBE ANOTHER SEVERE RISK ON TUESDAY AFTERNOON/EVENING...ALTHOUGH CONFIDENCE IS QUITE LOW ON THE LIKELIHOOD/EVOLUTION OF THE LATTER. IN OTHER DEPARTMENTS...TOMORROW IS CURRENTLY EXPECTED TO BE THE OVERALL-HOTTEST AFTERNOON OF THE SUMMER SO FAR FOR MOST OF THE CWA...AND A HEAT ADVISORY HAS BEEN ISSUES FOR SEVERAL SOUTHERN/SOUTHEAST COUNTIES. 21Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A SOMEWHAT SUBTLE-BUT EVIDENT EAST-WEST QUASI STATIONARY GENERALLY STRETCHED ACROSS THE SOUTHERN HALF OF NEBRASKA. IN THE WIND-FIELD...THIS BOUNDARY SEPARATES A STEADY 15+ MPH SOUTHERLY BREEZE IN NORTH CENTRAL KANSAS...FORM A LIGHTER...GENERALLY EAST-SOUTHEAST BREEZE WITHIN MOST OF THE NEBRASKA CWA. ITS ALSO SOMEWHAT OF A MOISTURE BOUNDARY...WITH MID-50S TO LOW 60S DEWPOINTS RESIDING IN THE DEEPLY MIXED AIRMASS TO THE SOUTH...AND HIGHER DEWPOINTS MID-60S TO NEAR 70 MOST AREAS ALONG/NORTH OF I-80. AS DISCUSSED EARLIER TODAY...NEAR-CRITICAL FIRE DANGER WILL PERSIST FOR A FEW MORE HOURS ESPECIALLY IN THE PHILLIPS/ROOKS COUNTY AREA IN KS. HIGH TEMPS THIS AFTERNOON WORKED OUT PRETTY WELL ACROSS THE SOUTHWESTERN 2/3 OF THE CWA RANGING GENERALLY 95-104 DEGREES...WHILE SOME NORTHEAST AREAS ARE STRUGGLING TO REACH 90 THANKS IN PART TO A BATCH OF MID LEVEL CLOUDS THAT FORMED ON THE BACK-SIDE OF AN MCV THAT HAS MOVED WELL EAST INTO WESTERN IA. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM CONTINUED QUASI-ZONAL FLOW ACROSS THE LOCAL AREA...BETWEEN THE LARGER-SCALE MID LEVEL RIDGE AXIS STRETCHED WEST-EAST FROM AZ TO OK...AND A VIGOROUS SHORTWAVE TROUGH MAKING ITS WAY ACROSS THE ID/MT/CANADA BORDER AREA. THE MAIN LOW-AMPLITUDE SHORTWAVE TROUGH OF INTEREST FOR THIS EVENING IS CURRENTLY LIFTING OUT OF WY INTO WESTERN NEB/SD. LATE THIS AFTERNOON INTO THIS EVENING...THE PRIMARY FOCUS IS ON HOW MUCH THUNDERSTORM COVERAGE THE CWA WILL SEE...AND WHETHER SOME OF THIS ACTIVITY COULD BECOME SEVERE. AT PRESENT TIME...RADAR INDICATES A FEW WEAK-ISH/HIGH-BASED STORMS NEAR THE STATE LINE IN THE SOUTHWESTERN CWA...LARGELY A RESULT OF VERY STEEP LOW-LEVEL LAPSE RATES IN THE HOT/DEEPLY MIXED AIRMASS OVER KS. MEANWHILE...OFF TO THE NORTHWEST...A FEW STRONG TO SEVERE STORMS HAVE TAKEN OFF IN NORTH CENTRAL/WESTERN NEB...IN AN ENVIRONMENT CHARACTERIZED BY AROUND 2000+ J/KG MLCAPE AND 30+ KNOTS OF 0-6KM DEEP LAYER SHEAR. LOCALLY...WITH THE EXCEPTION OF THE HIGH-BASED STORMS IN OUR SOUTH...MODEL SOUNDINGS SUGGEST THERE IS JUST ENOUGH OF A CAP IN PLACE TO KEEP CONVECTION FROM DEVELOPING OVERHEAD IN MOST OF THE CENTRAL/NORTHERN CWA...AIDED IN PART BY SUBSIDENCE BEHIND THE DEPARTING MCV. AS HAS BEEN THE CASE FOR DAYS NOW...CONFIDENCE IN THE DETAILS IS LOW IN THIS WEAKLY FORCED PATTERN...BUT TAKING CUE FROM THE LATEST RAP/HRRR AND 12Z 4KM WRF- NMM...THE GENERAL EXPECTATION IS FOR MOST OF THE CWA TO REMAIN STORM FREE THROUGH AT LEAST 00Z/7PM...BEFORE STORM CHANCES GRADUALLY INCREASE THROUGH THE EVENING HOURS ESPECIALLY NEAR/NORTH OF I-80...AND LIKELY MAINLY AS A FUNCTION OF ACTIVITY MOVING IN FROM WESTERN NEBRASKA...ALTHOUGH LOCAL INITIATION NEAR THE SURFACE BOUNDARY CANNOT BE RULED OUT EITHER. BOTH THE WRF-NMM AND HRRR ARE FAIRLY AGGRESSIVE BRINGING A CLUSTER OF STORMS...POSSIBLY A SEMI- ORGANIZED MCS ACROSS ESPECIALLY THE NORTHERN 1/2 OF THE CWA THIS EVENING...BUT A SIMILAR MODEL DEPICTION YESTERDAY ENDED UP BEING A BIT OVERDONE...AND THUS HAVE CAPPED POPS AT NO HIGHER THAN 50 PERCENT AT LEAST FOR NOW. WITH MLCAPE REMAINING 1000+ J/KG WELL INTO THE EVENING HOURS AND WITH AT LEAST MODEST SHEAR...AT LEAST A LOCALIZED LARGE HAIL AND ESPECIALLY A WIND THREAT IS QUITE POSSIBLE ESPECIALLY IF STORMS TO THE WEST CAN ORGANIZE AND DEVELOP A COLD POOL. AGREE WITH SPC IN HIGHLIGHTING THE NORTHERN 1/2 OF THE CWA FOR THE GREATEST SEVERE THREAT...BUT JUST CANNOT RULE OUT A STRONG TO SEVERE STORM ANYWHERE IN THE CWA THIS EVENING. ALTHOUGH THE MAIN SEVERE THREAT SHOULD BE ON THE WANE BY MIDNIGHT...LINGERED LOW POPS THROUGH THE NIGHT ESPECIALLY ACROSS THE EASTERN 2/3 OF THE CWA TO ACCOUNT FOR ACTIVITY PERSISTING OR NEWLY-DEVELOPING WITHIN THE LOW LEVEL JET AXIS...AND JUST AHEAD ON APPROACHING COLD FRONT. IF NOTHING ELSE...HOPEFULLY PARTS OF THE CWA CAN RECEIVE SOME MUCH-NEEDED RAINS TONIGHT...BECAUSE THIS MAY BE ONE OF THE BETTER CHANCES FOR AWHILE. TEMPERATURE-WISE...MADE ONLY MINOR TWEAKS TO LOWS...WITH THE PREVALENT LIGHT SOUTHERLY BREEZE HOLDING MOST AREAS UP INTO THE 70-75 RANGE. ALTHOUGH AT LEAST LIGHT FOG DEVELOPMENT CANNOT BE RULED OUT LATE TONIGHT ESPECIALLY IN AREAS THAT RECEIVE RAIN...THE PROBABILITY/MAGNITUDE SEEMED LOW ENOUGH TO OMIT FROM THE FORECAST. TURNING TO TUESDAY DAYTIME...REALLY DON/T THINK SEVERE STORMS ARE GOING TO END UP BEING MUCH OF A STORY...AT LEAST THROUGH THE VAST MAJORITY OF THE DAY. ALOFT...QUASI-ZONAL FLOW WILL START TO TURN A BIT MORE NORTHWESTERLY IN RESPONSE TO THE PASSAGE OF A FAIRLY VIGOROUS SHORTWAVE TROUGH FROM EASTERN MT TOWARD NORTHERN MN. AT THE SURFACE...A FAIRLY WEAK COLD FRONT...MORE EVIDENT IN THE WIND FIELD THAN ON A THERMOMETER...WILL WORK SOUTHWARD ACROSS THE CWA AS THE DAY WEARS ON...WITH MOST AREAS SEEING A FEW HOURS OF LIGHT/VARIABLE WINDS BEFORE A SLIGHTLY MORE STEADY NORTHERLY BREEZE SETTLES IN. ALONG AND ESPECIALLY JUST AHEAD OF THIS BOUNDARY...A LOW LEVEL THERMAL RIDGE WILL EXTEND INTO THE CWA FROM THE SOUTHWEST...PROMOTING WHAT SHOULD BE THE HIGHEST HEAT-INDEX READINGS OF THE SUMMER SO FAR FOR MOST ALL OF THE CWA...AND IN SOME SPOTS THE HOTTEST ACTUAL AIR TEMPERATURES. THE ONLY CAVEATS WOULD BE AN UNEXPECTEDLY STRONG OUTFLOW BOUNDARY FROM CONVECTION TONIGHT THAT MIGHT HELP ACCELERATE THE COLD FRONT SOUTHWARD FASTER...AND MAYBE A DENSER-THAN-EXPECTED COVERAGE OF MID LEVEL CLOUDS OR LINGERING WEAK CONVECTION. BUT ASSUMING NEITHER ONE OF THESE CAVEATS PLAY OUT...HAVE AIMED FOR ACTUAL HIGH TEMPS RANGING FROM MID 90S NORTH...UPPER 90S CENTRAL...AND 100-106 NEAR AND SOUTH OF THE STATE LINE. HEAT INDEX VALUES OF 100+ ARE FORECAST ACROSS MUCH OF THE SOUTHERN AND EASTERN HALVES OF THE CWA...AND HAVE ISSUED A HEAT ADVISORY FOR ALL KS ZONES ALONG WITH WEBSTER- NUCKOLLS-THAYER IN NEBRASKA...WHICH HAVE THE HIGHEST LIKELIHOOD OF REACHING OR EXCEEDING A 105 HEAT INDEX. FORTUNATELY FOR FIRE WEATHER CONCERNS IN THE FAR SOUTHWEST COUNTIES...SUSTAINED WINDS/GUSTS DO NOT LOOK TO EXCEED 20 MPH DURING THE PEAK OF AFTERNOON HEATING. AS FOR CONVECTIVE CHANCES...FORECAST SOUNDINGS SUGGEST THAT A FAIRLY STRONG CAP SHOULD PREVAIL THROUGH THE DAY AS VERY WARM MID LEVEL TEMPS OVERSPREAD THE AREA. AS A RESULT...OTHER THAN A LINGERING SLIGHT CHANCE OF MORNING STORMS IN EASTERN COUNTIES RIGHT AWAY IN THE MORNING...WILL AIM FOR A DRY MAJORITY OF THE DAY...BEFORE BRINGING BACK SLIGHT STORM CHANCES POST- 21Z/4PM. THERE ARE AT LEAST TWO POSSIBLE FOCUSES FOR LATE AFTERNOON DEVELOPMENT...THE MAIN COLD FRONT WHICH SHOULD BE VERY NEAR THE FAR SOUTHEAST CORNER OF THE CWA...AND ALSO FORCING FROM THE SOUTHERN EDGE OF THE NORTHERN PLAINS SHORTWAVE TROUGH...WHICH COULD KICK OFF CONVECTION CLOSER TO THE NORTHERN EDGE OF THE CWA. HOWEVER...MODELS SUCH AS THE 12Z 4KM WRF-NMM ADVERTISE ESSENTIALLY NO LATE AFTERNOON STORMS ANYWHERE IN THE CWA...SO THUS ONLY THE SLIGHT POPS. IF STORMS WOULD MANAGE TO FORM...A CONDITIONAL SEVERE THREAT COULD EXIST ALMOST ANYWHERE IN THE CWA...POTENTIALLY EVEN WEST OF THE SPC DAY 2 SLIGHT RISK AREA. PLENTY OF UNCERTAINTY FOR SURE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 455 PM CDT MON JUL 8 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY NIGHT AND AGAIN SATURDAY NIGHT THROUGH MONDAY AND TEMPERATURES. MODELS ARE FAIRLY SIMILAR IN BUILDING AN UPPER LEVEL RIDGE ACROSS THE AREA DURING THE PERIOD...BUT THE DETAILS OF THE TIMING MAINLY WEAK UPPER LEVEL WAVES THROUGH THE AREA ARE SOMEWHAT DIFFERENT BETWEEN THE MODELS. THIS BRINGS SOME UNCERTAINTY IN WHEN THERE WILL BE SOME CHANCES FOR THUNDERSTORMS. A SURFACE COLD FRONT WILL MOVE TO THE SOUTH ACROSS THE SOUTHERN PART OF THE FORECAST AREA DURING THE EVENING. AN UPPER LEVEL WAVE WILL ALSO BE MOVING THROUGH THE AREA. EXPECT SOME THUNDERSTORMS ALONG THAT BOUNDARY DURING THE EVENING...BUT OVERNIGHT THEY SHOULD MOVE OUT OF THE AREA. MUCAPE IS THE HIGHEST DURING THE EARLY EVENING HOURS AND DIMINISHES SOME LATER IN THE EVENING...BUT STILL REMAINS AROUND 2500 J/KG. EXPECT THAT THERE COULD BE SOME SEVERE WEATHER DURING THE EVENING. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE AREA ON WEDNESDAY. HIGH TEMPERATURES WILL BE AROUND 10 DEGREES COOLER THAN ON TUESDAY. WEDNESDAY SHOULD REMAIN DRY...BUT AN UPPER LEVEL WAVE MOVES ACROSS THE RIDGE AND THERE COULD BE SOME ISOLATED SHOWERS AND THUNDERSTORMS THAT MOVE OFF THE HIGH PLAINS DURING THE NIGHT TIME HOURS. THE SURFACE HIGH MOVES OFF TO THE EAST ON THURSDAY AND THE SURFACE PRESSURE GRADIENT TIGHTENS. WINDS AT 850MB ARE ONLY 20 TO 25 KTS SO EXPECT SOME BREEZY CONDITIONS. WITH WINDS FROM THE SOUTH THE TEMPERATURES WILL WARM UP. THE UPPER LEVEL RIDGE CONTINUES TO BUILD ACROSS THE AREA FOR THE PERIOD THURSDAY THROUGH SATURDAY. EXPECT TEMPERATURES TO WARM A LITTLE EACH DAY THROUGH THE PERIOD. THE UPPER LEVEL RIDGE REMAINS IN PLACE FOR SATURDAY NIGHT THROUGH MONDAY...BUT IT IS MORE OF AN UPPER LEVEL HIGH PRESSURE SYSTEM ACROSS THE AREA. IT IS FAIRLY BROAD AND THERE ARE A FEW UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA. SIMILAR TO THE PAST WEEK OR SO EACH OF THESE UPPER LEVEL WAVES HAS A CHANCE FOR SOME THUNDERSTORMS. DO NOT EXPECT THAT IT WILL BE WIDESPREAD OR THAT EVERYONE WILL HAVE SOME PRECIPITATION. THE TIMING AND THE LOCATION OF ANY PRECIPITATION IS IN QUESTION. WITH A FEW MORE CLOUDS AND THE CHANCE FOR SOME PRECIPITATION THE TEMPERATURES WILL BE A LITTLE COOLER. && .AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1250 PM CDT MON JUL 8 2013 FOR NOW...VFR CEILING/VISIBILITY IS FORECAST THROUGH THE NEXT 24 HOURS...ALTHOUGH THERE A FEW CAVEATS TO SPEAK OF THAT COULD LEAD TO AT LEAST BRIEF DETERIORATION. THE FIRST CAVEAT IS THE POTENTIAL FOR THUNDERSTORMS...POTENTIALLY STRONG TO SEVERE...TO MOVE IN FROM THE WEST THIS EVENING. ALTHOUGH THIS SEEMS TO BE AN INCREASING BET...WILL CONTINUE TO KEEP IT SIMPLE FOR NOW WITH ONLY A VICINITY THUNDERSTORM MENTION FROM 01Z-09Z...AND DEFER TO LATER FORECASTS TO BETTER PIN DOWN POTENTIAL TIMING AND IMPACT TO THE TERMINAL IF NEED BE. ONCE THE STORM CHANCE ENDS...THE LATE NIGHT/EARLY MORNING HOURS COULD SEE ANOTHER ROUND OF MVFR VISIBILITY RESTRICTION IN LIGHT FOG...BUT GIVEN LOW CONFIDENCE IN THIS OCCURRING WILL ONLY HINT AT IT FOR NOW WITH A LOW-END VFR VISIBILITY RESTRICTION BETWEEN 09Z-15Z. ITS POSSIBLE THAT ANY PRECEDING RAINFALL COULD ENHANCE THE PROBABILITY OF FOG. OTHERWISE...THERE COULD ALSO BE A PERIOD OF LOW LEVEL WIND SHEAR TONIGHT AS WINDS BETWEEN 1 AND 2 THOUSAND FEET ACCELERATE BETWEEN 40-45KT FROM THE SOUTHWEST...BUT AT THIS TIME THE MAGNITUDE AND DURATION OF SHEAR APPEARS SMALL ENOUGH TO LEAVE OUT OF THE TAF...WITH THUNDERSTORM-RELATED WIND ISSUES POTENTIALLY BEING A BIGGER ISSUE. AT THE SURFACE...AND APART FROM ANY THUNDERSTORM-MODIFIED EFFECTS...BREEZES ARE EXPECTED TO AVERAGE UNDER 12KT THROUGH THE PERIOD...INITIALLY SOUTHERLY BEFORE BECOMING MORE WESTERLY AHEAD OF AN INVADING COLD FRONT TUESDAY MORNING. A SWITCH TO NORTHERLY BREEZES COULD OCCUR TOWARD THE VERY END OF THE PERIOD...BUT WILL DEFER TO NEXT FORECAST TO INTRODUCE THIS WIND SHIFT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...HEAT ADVISORY FROM NOON TO 7 PM CDT TUESDAY FOR NEZ085>087. KS...HEAT ADVISORY FROM NOON TO 7 PM CDT TUESDAY FOR KSZ005>007- 017>019. && $$ SHORT TERM...PFANNKUCH LONG TERM...JCB AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1257 PM CDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CDT MON JUL 8 2013 ANOTHER ACTIVE SEVERE WEATHER DAY IS EXPECTED BEGINNING THIS AFTERNOON THROUGH THE OVERNIGHT HOURS TONIGHT. THE FOCUS FOR STORM DEVELOPMENT REVOLVES AROUND A STRONG UPPER LEVEL DISTURBANCE MOVING THROUGH THE DAKOTAS. A WEAKER DISTURBANCE WILL APPROACH SWRN NEB LATE THIS AFTERNOON PERHAPS FOCUSING ANOTHER CLUSTER OF STRONG TO SEVERE STORMS. THE DISTURBANCE MOVING THROUGH THE DAKOTAS IS EXPECTED TO LIFT A 700 MB WARM FRONT THROUGH SWRN NEB...PERHAPS CAPPING THE ATMOSPHERE THIS EVENING. IT WOULD APPEAR THERE IS A WINDOW FOR SEVERE STORM DEVELOPMENT ACROSS SWRN NEB LATE THIS AFTERNOON BEFORE THE ATMOSPHERE BECOMES CAPPED THIS EVENING. THERE ARE NO HOLDS BARRED ACROSS NCNTL AND NW NEB LATE THIS AFTN AND THIS EVENING WHERE THE CAP WILL BE WEAKER AND JUST AS UNSTABLE AS THE SOUTHWEST. THE RAP SUGGESTS STORMS COULD FIRE ACROSS NCNTL NEB LATE THIS AFTN JUST AHEAD OF THE MID LEVEL WARM FRONT. AT THE SFC A WARM FRONT WILL LIE ALONG INTERSTATE 80 PROVIDING AN OPPORTUNITY FOR STORM DEVELOPMENT THERE. THUS THE FCST USES A MULTIMODEL BLEND FOR HIGHEST POPS...40S...ACROSS THE NORTH AND ISOLATED POPS ACROSS SWRN NEB. HIGHS TODAY SHOULD REACH WELL INTO THE 90S ALONG AND SOUTH OF THE SFC FRONT NEAR INTERSTATE 80 AND 80S ACROSS NCNTL NEB. LOWS TONIGHT FALL INTO THE 60S TO AROUND 70. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 312 AM CDT MON JUL 8 2013 A COLD FRONT WILL BE DRIVEN SOUTH THROUGH THE AREA TUESDAY...AS A STRONG SHORT WAVE TROUGH SKIRTS EAST ACROSS THE NORTHERN PLAINS AND SOUTHERN CANADA. THIS WILL BRING A TEMPORARY REST FROM T-STORM ACTIVITY...AS THE BEST FOCUS WILL SHIFT SOUTH AND EAST OF THE AREA ALONG THE FRONT. WEDNESDAY THE FRONT WILL BEGIN TO LIFT BACK NORTH AS A WARM FRONT...WITH A WARM MOIST EASTERLY UPSLOPE FLOW LIKELY TO IGNITE T-STORMS ACROSS THE PANHANDLE WEDNESDAY AFTERNOON. THESE SHOULD MOVE EAST INTO CENTRAL/SOUTHWEST NEBRASKA WEDNESDAY EVENING. THE UPPER LEVEL RIDGE OF HIGH PRESSURE IS STILL EXPECTED TO BUILD NORTH OVER THE AREA THURSDAY INTO FRIDAY. WARMING MID LEVEL TEMPERATURES WILL LIKELY CAP THE ATMOSPHERE...AND T-STORM CHANCES WILL DIMINISH. HOT WEATHER CAN ALSO BE ANTICIPATED AS THE RIDGE BUILDS IN...WITH HIGHS IN THE MID 90S TO AROUND 100 DEGREES. ANOTHER STRONG SHORTWAVE TROUGH WILL PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTHERN CANADA SATURDAY AND SUNDAY. THIS APPEARS TO DRIVE ANOTHER COLD FRONT SOUTH INTO THE AREA...WITH RETURNING CHANCES FOR T-STORMS AND SOMEWHAT COOLER TEMPERATURES BY SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1255 PM CDT MON JUL 8 2013 VFR CONDITIONS EARLY THIS AFTERNOON...HOWEVER EXPECT ANOTHER ROUND OF THUNDERSTORMS TO DEVELOP OVER WESTERN NEBRASKA AND MOVE ACROSS THE AREA THIS EVENING. IMPACT IS EXPECTED AT BOTH TERMINAL SITES...WITH STORMS CAPABLE OF GUSTY WINDS POSSIBLY SOME HAIL. OVERNIGHT...FOLLOWING THE CONVECTION...AS SKIES RETURN TO VFR AND TEMPS COOL...RICH BOUNDARY LAYER MOISTURE MAY RESULT IN THE DEVELOPMENT OF FOG...LOCALLY LESS THAN 1SM. DID NOT GO THAT LOW IN THE TAF YET...AS SOME UNCERTAINTY TO HOW WIDESPREAD THE FOG WILL BE. ANY FOG THAT DOES DEVELOP SHOULD QUICKLY BURN OFF WITH VFR CONDITIONS RETURNING FOR THE MID AND LATE MORNING HOURS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...MASEK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
619 AM CDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CDT MON JUL 8 2013 ANOTHER ACTIVE SEVERE WEATHER DAY IS EXPECTED BEGINNING THIS AFTERNOON THROUGH THE OVERNIGHT HOURS TONIGHT. THE FOCUS FOR STORM DEVELOPMENT REVOLVES AROUND A STRONG UPPER LEVEL DISTURBANCE MOVING THROUGH THE DAKOTAS. A WEAKER DISTURBANCE WILL APPROACH SWRN NEB LATE THIS AFTERNOON PERHAPS FOCUSING ANOTHER CLUSTER OF STRONG TO SEVERE STORMS. THE DISTURBANCE MOVING THROUGH THE DAKOTAS IS EXPECTED TO LIFT A 700 MB WARM FRONT THROUGH SWRN NEB...PERHAPS CAPPING THE ATMOSPHERE THIS EVENING. IT WOULD APPEAR THERE IS A WINDOW FOR SEVERE STORM DEVELOPMENT ACROSS SWRN NEB LATE THIS AFTERNOON BEFORE THE ATMOSPHERE BECOMES CAPPED THIS EVENING. THERE ARE NO HOLDS BARRED ACROSS NCNTL AND NW NEB LATE THIS AFTN AND THIS EVENING WHERE THE CAP WILL BE WEAKER AND JUST AS UNSTABLE AS THE SOUTHWEST. THE RAP SUGGESTS STORMS COULD FIRE ACROSS NCNTL NEB LATE THIS AFTN JUST AHEAD OF THE MID LEVEL WARM FRONT. AT THE SFC A WARM FRONT WILL LIE ALONG INTERSTATE 80 PROVIDING AN OPPORTUNITY FOR STORM DEVELOPMENT THERE. THUS THE FCST USES A MULTIMODEL BLEND FOR HIGHEST POPS...40S...ACROSS THE NORTH AND ISOLATED POPS ACROSS SWRN NEB. HIGHS TODAY SHOULD REACH WELL INTO THE 90S ALONG AND SOUTH OF THE SFC FRONT NEAR INTERSTATE 80 AND 80S ACROSS NCNTL NEB. LOWS TONIGHT FALL INTO THE 60S TO AROUND 70. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 312 AM CDT MON JUL 8 2013 A COLD FRONT WILL BE DRIVEN SOUTH THROUGH THE AREA TUESDAY...AS A STRONG SHORT WAVE TROUGH SKIRTS EAST ACROSS THE NORTHERN PLAINS AND SOUTHERN CANADA. THIS WILL BRING A TEMPORARY REST FROM T-STORM ACTIVITY...AS THE BEST FOCUS WILL SHIFT SOUTH AND EAST OF THE AREA ALONG THE FRONT. WEDNESDAY THE FRONT WILL BEGIN TO LIFT BACK NORTH AS A WARM FRONT...WITH A WARM MOIST EASTERLY UPSLOPE FLOW LIKELY TO IGNITE T-STORMS ACROSS THE PANHANDLE WEDNESDAY AFTERNOON. THESE SHOULD MOVE EAST INTO CENTRAL/SOUTHWEST NEBRASKA WEDNESDAY EVENING. THE UPPER LEVEL RIDGE OF HIGH PRESSURE IS STILL EXPECTED TO BUILD NORTH OVER THE AREA THURSDAY INTO FRIDAY. WARMING MID LEVEL TEMPERATURES WILL LIKELY CAP THE ATMOSPHERE...AND T-STORM CHANCES WILL DIMINISH. HOT WEATHER CAN ALSO BE ANTICIPATED AS THE RIDGE BUILDS IN...WITH HIGHS IN THE MID 90S TO AROUND 100 DEGREES. ANOTHER STRONG SHORTWAVE TROUGH WILL PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTHERN CANADA SATURDAY AND SUNDAY. THIS APPEARS TO DRIVE ANOTHER COLD FRONT SOUTH INTO THE AREA...WITH RETURNING CHANCES FOR T-STORMS AND SOMEWHAT COOLER TEMPERATURES BY SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 614 AM CDT MON JUL 8 2013 LIFR ACROSS KVTN AND KANW SHOULD MIX OUT TO VFR BY 13Z-15Z AT THE LATEST. SIMILARLY...THE SCATTERED THUNDERSTORMS ACROSS NW NEB SHOULD WEAKEN AFTER SUNRISE BEFORE REACHING KVTN...THIS IS ASSUMING THEY ARE NOCTURNALLY DRIVEN. OTHERWISE THERE IS NO REAL CHANGE TO THE FORECAST...SCATTERED STRONG OR SEVERE THUNDERSTORMS ARE EXPECTED TO REDEVELOP LATE THIS AFTERNOON OR EARLY EVENING ROUGHLY 22Z-02Z WITH ACTIVITY CONTINUING WELL INTO THE EVENING HOURS. SCATTERED STORMS SHOULD FORM FIRST ACROSS THE NORTH AND LAST THE LONGEST ACROSS NRN NEB. ISOLATED STORMS COULD DISSIPATE THIS EVENING AROUND KLBF AS A CAP IS EXPECTED TO DEVELOP. THUS VFR COULD DEVELOP ACROSS SWRN NEB THIS EVENING WHILE STORMS CONTINUE ACROSS NRN NEB. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
334 AM CDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CDT MON JUL 8 2013 ANOTHER ACTIVE SEVERE WEATHER DAY IS EXPECTED BEGINNING THIS AFTERNOON THROUGH THE OVERNIGHT HOURS TONIGHT. THE FOCUS FOR STORM DEVELOPMENT REVOLVES AROUND A STRONG UPPER LEVEL DISTURBANCE MOVING THROUGH THE DAKOTAS. A WEAKER DISTURBANCE WILL APPROACH SWRN NEB LATE THIS AFTERNOON PERHAPS FOCUSING ANOTHER CLUSTER OF STRONG TO SEVERE STORMS. THE DISTURBANCE MOVING THROUGH THE DAKOTAS IS EXPECTED TO LIFT A 700 MB WARM FRONT THROUGH SWRN NEB...PERHAPS CAPPING THE ATMOSPHERE THIS EVENING. IT WOULD APPEAR THERE IS A WINDOW FOR SEVERE STORM DEVELOPMENT ACROSS SWRN NEB LATE THIS AFTERNOON BEFORE THE ATMOSPHERE BECOMES CAPPED THIS EVENING. THERE ARE NO HOLDS BARRED ACROSS NCNTL AND NW NEB LATE THIS AFTN AND THIS EVENING WHERE THE CAP WILL BE WEAKER AND JUST AS UNSTABLE AS THE SOUTHWEST. THE RAP SUGGESTS STORMS COULD FIRE ACROSS NCNTL NEB LATE THIS AFTN JUST AHEAD OF THE MID LEVEL WARM FRONT. AT THE SFC A WARM FRONT WILL LIE ALONG INTERSTATE 80 PROVIDING AN OPPORTUNITY FOR STORM DEVELOPMENT THERE. THUS THE FCST USES A MULTIMODEL BLEND FOR HIGHEST POPS...40S...ACROSS THE NORTH AND ISOLATED POPS ACROSS SWRN NEB. HIGHS TODAY SHOULD REACH WELL INTO THE 90S ALONG AND SOUTH OF THE SFC FRONT NEAR INTERSTATE 80 AND 80S ACROSS NCNTL NEB. LOWS TONIGHT FALL INTO THE 60S TO AROUND 70. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 312 AM CDT MON JUL 8 2013 A COLD FRONT WILL BE DRIVEN SOUTH THROUGH THE AREA TUESDAY...AS A STRONG SHORT WAVE TROUGH SKIRTS EAST ACROSS THE NORTHERN PLAINS AND SOUTHERN CANADA. THIS WILL BRING A TEMPORARY REST FROM T-STORM ACTIVITY...AS THE BEST FOCUS WILL SHIFT SOUTH AND EAST OF THE AREA ALONG THE FRONT. WEDNESDAY THE FRONT WILL BEGIN TO LIFT BACK NORTH AS A WARM FRONT...WITH A WARM MOIST EASTERLY UPSLOPE FLOW LIKELY TO IGNITE T-STORMS ACROSS THE PANHANDLE WEDNESDAY AFTERNOON. THESE SHOULD MOVE EAST INTO CENTRAL/SOUTHWEST NEBRASKA WEDNESDAY EVENING. THE UPPER LEVEL RIDGE OF HIGH PRESSURE IS STILL EXPECTED TO BUILD NORTH OVER THE AREA THURSDAY INTO FRIDAY. WARMING MID LEVEL TEMPERATURES WILL LIKELY CAP THE ATMOSPHERE...AND T-STORM CHANCES WILL DIMINISH. HOT WEATHER CAN ALSO BE ANTICIPATED AS THE RIDGE BUILDS IN...WITH HIGHS IN THE MID 90S TO AROUND 100 DEGREES. ANOTHER STRONG SHORTWAVE TROUGH WILL PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTHERN CANADA SATURDAY AND SUNDAY. THIS APPEARS TO DRIVE ANOTHER COLD FRONT SOUTH INTO THE AREA...WITH RETURNING CHANCES FOR T-STORMS AND SOMEWHAT COOLER TEMPERATURES BY SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 110 AM CDT MON JUL 8 2013 SCATTERED STRONG OR SEVERE THUNDERSTORMS ARE EXPECTED TO REDEVELOP LATE MONDAY AFTERNOON OR EARLY EVENING ROUGHLY 23Z-02Z WITH ACTIVITY CONTINUING WELL INTO THE EVENING HOURS. THE ONGOING CONVECTION...LIGHT RAIN AND MVFR CIGS SHOULD EXIT SWRN NEB BY 09Z. VFR IS EXPECTED ALL AREAS THEREAFTER UNTIL 22Z- 02Z. PRIME AREAS FOR STORM DEVELOPMENT ARE SWRN NEB AND NORTHWEST NEB. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
808 PM EDT TUE JUL 9 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN CENTERED OFF THE SOUTHEAST COAST WITH A SURFACE TROUGH ALONG THE PIEDMONT THROUGH MID WEEK. A FRONTAL SYSTEM WILL APPROACH THE AREA FRIDAY AND STALL OVER THE AREA SATURDAY. HIGH PRESSURE WILL BUILD AGAIN EARLY NEXT WEEK. && .NEAR TERM /TONIGHT/... AS OF 8 PM TUES...SHOWERS AND TSTORMS ARE WANING THIS EVENING DUE TO LOSS OF HEATING. ADJUSTED POPS/WX/QPF TO ACCOUNT FOR THESE TRENDS WITH HIGHEST POPS FROM VANCEBORO NORTH AND EAST TO WILLIAMSTON AND CRESWELL. EXPECT CONVECTION TO CONTINUE TO DIMINISH OVER THE NEXT FEW HOURS. SW FLOW WILL PERSIST AROUND 5 KTS. LOWS WILL BE SIMILAR TO TUES MORNING...MINIMUMS IN THE LOWS 70S INLAND AND MID 70S COASTAL AREA. 22Z HRRR SUGGEST WEAK SHOWERS APPROACHING THE SOUTHERN COAST LATE TONIGHT...AND WITH WEAK CONVECTION ABOUT 100 NMI OFF THE COAST CURRENTLY...WILL HOLD ON TO SLIGHT CHANCE/ISOLATED SHOWERS/TSTORMS FOR THE SOUTHERN COAST AND COASTAL WATERS NEAR SUNRISE. && .SHORT TERM /WEDNESDAY/... AS OF 3 PM TUE...THE BERMUDA HIGH WILL REMAIN OFFSHORE AND PIEDMONT TROUGH WILL CONTINUE TO BRING A MOIST SW FLOW ACROSS THE AREA. WITH THE MID LEVELS BECOMING MORE ZONAL ALOFT...THIS WILL REDUCE THE AMOUNT OF FORCING. BUT WITH THE AFTERNOON SEA BREEZE AND PWATS INCREASING AROUND TO 2.0"...THIS WILL AID THE DEVELOPMENT OF SHOWERS/TSTORMS ACROSS INLAND. EXPECT MAX TEMPERATURES TO RANGE LOW/MID 80S COASTAL AREA TO UPPER 80S/LOW 90S INLAND. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... AS OF 315 PM TUESDAY...THE INITIAL PORTION OF THE LONG TERM FORECAST WILL BE CHARACTERIZED BY A DEEPENING LONGWAVE TROUGH OVER THE EASTERN UNITED STATES LEADING TO A WET AND RATHER UNSETTLED PERIOD. MODEL TIME SECTIONS FROM THE GFS AND ECMWF INDICATE THE DEEPEST MOISTURE AND STRONGEST 700-500 MB OMEGA SHOULD BEGIN AROUND MIDDAY THURSDAY AND CONTINUE THROUGH MUCH OF THE DAY FRIDAY. HAVE RAMPED UP POPS TO LIKELY FROM ABOUT MIDDAY THURSDAY THROUGH FRIDAY EVENING. WITH PRECIPITABLE WATER VALUES BETWEEN 2 AND 2.25 INCHES...THE POTENTIAL WILL EXIST FOR HEAVY RAINFALL AMOUNTS. A COLD FRONT SHOULD BE ABLE TO PIVOT TO THE SOUTH OF THE REGION FRIDAY AFTERNOON WITH HIGH PRESSURE BUILDING FROM THE NORTH FOR SATURDAY. THE BIG QUESTION MARK WILL CONCERN TROPICAL CYCLONE CHANTAL...OR WHATEVER FORM IT REMAINS IN OVER THE WEEKEND. CURRENTLY APPEARS THAT THE SURFACE RIDGE TO THE NORTH SHOULD STEER THE SYSTEM WEST AND KEEP IT WELL SOUTH OF OUR REGION...BUT PERSONS SHOULD CONTINUE TO MONITOR LATER STATEMENT ON CHANTAL. FOR EARLY NEXT WEEK...WE RETURN TO A MORE TYPICAL SUMMERTIME REGIME WITH BERMUDA HIGH TO THE EAST AND A WEAK TROUGH INLAND KEEPING WARM AND HUMID WEATHER AND A DAILY CHANCE OF SHOWERS AND THUNDERSTORMS...ESPECIALLY INLAND. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /TONIGHT AND WEDNESDAY/... AS OF 8 PM TUE...MOSTLY VFR CONDITIONS ARE EXPECTED FOR THE TERMINALS FOR THE TAF PERIOD. ISOLATED SHOWERS/TSTORMS WILL CONTINUE TO DIMINISH THIS EVENING BUT WILL CARRY VCSH IN THE TAFS FOR NOW TO ACCOUNT FOR POSSIBLE SHOWER ACTIVITY. FORECAST SOUNDINGS INDICATE INLAND SITES PGV/ISO AGAIN MAY DECOUPLE AND OBSERVE LOW STRATUS SO WILL HOLD ON TO MVFR CEILINGS WITH THIS PACKAGE. CONDITIONS WILL IMPROVE TO VFR WITH CHANCES OF SHOWERS/TSTORMS DEVELOPING AGAIN IN THE AFTERNOON. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 315 PM TUESDAY...LOW CEILINGS AND A RATHER WET PERIOD IS ON TAP FOR THURSDAY AND FRIDAY AS AN UPPER LEVEL LONGWAVE TROUGH BUILDS EAST. EXTENSIVE MVFR AND IFR CEILINGS AND VSBYS ARE QUITE LIKELY FROM MIDDAY THURSDAY THROUGH THE DAY FRIDAY. PRECIPITATION COVERAGE SHOULD DROP A BIT FRIDAY AND SATURDAY WITH LARGELY VFR CONDITIONS EXCEPT FOR ISOLATED SHOWERS/TSTMS AND ANY LATE NIGHT OR EARLY MORNING STRATUS AND FOG...WHICH COULD REDUCE CEILINGS AND VSBYS TO MVFR AND BRIEFLY IFR/LIFR CATEGORIES. && .MARINE... SHORT TERM /TONIGHT AND WEDNESDAY/... AS OF 805 PM MONDAY...LATEST SURFACE AND BUOY OBSERVATIONS INDICATE SW TO S WIND 5-15 KNOTS WITH SEAS GENERALLY 2-3 FT. NO CHANGES NEEDED TO THE EVENING UPDATE. THE BERMUDA HIGH WILL CONTINUE TO BE OFFSHORE WITH A TROUGH PERSISTING ACROSS THE PIEDMONT WILL MAINTAIN THE SW FLOW ACROSS ALL WATERS. WINDS WILL BE 10-20 KTS TONIGHT INTO WED. SEAS ARE EXPECTED TO INCREASE IN THE NORTHERN/CENTRAL WATERS TO 2-4 FT OVERNIGHT. THE SOUTHERN WATERS WILL REMAIN 2-3 FT THROUGH WED. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 315 PM TUESDAY...BASED ON INCREASING SURFACE GRADIENT AS DEEP LONGWAVE TROUGH DEEPENS OVER THE EASTERN UNITED STATES...HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE WATERS NORTH OF CAPE LOOKOUT AND THE PAMLICO SOUND...MAINLY FOR WIND...WITH THE EXCEPTION OF THE CENTRAL WATERS WHERE SOME 6 FOOT SEAS WILL BE POSSIBLE THURSDAY INTO FRIDAY. A WEAK COL IN THE PRESSURE PATTERN WILL LEAD TO LIGHTER WINDS SATURDAY. CURRENT MODEL PROJECTIONS KEEP TROPICAL CYCLONE CHANTAL... IN WHATEVER FORM IT REMAINS...TO OUR SOUTH WITH A RIDGE TO OUR NORTH SUNDAY...BUT INTERESTS SHOULD CONTINUE TO MONITOR THE LATEST INFORMATION ON CHANTAL. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM WEDNESDAY TO 6 AM EDT FRIDAY FOR AMZ135-150-152-154-156. && $$ SYNOPSIS...BM NEAR TERM...DAG/BM SHORT TERM...BM LONG TERM...CTC AVIATION...CTC/DAG/BM MARINE...CTC/DAG/BM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
800 PM EDT TUE JUL 9 2013 .SYNOPSIS... A WEAK UPPER LEVEL LOW PRESSURE TROUGH WILL HOLD OVER THE EASTERN U.S. THROUGH WEDNESDAY. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH THE AREA FROM THE NORTHEAST LATE WEDNESDAY... AND SWING THROUGH THE REGION THURSDAY THROUGH FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 230 PM TUESDAY... THROUGH TONIGHT: WATER VAPOR IMAGERY SHOWS A SUBTLE VORTICITY MAX DROPPING SOUTHEAST THROUGH CENTRAL... AND THIS FEATURE COMBINED WITH DAYTIME HEATING/DESTABILIZATION (MLCAPE OF 2000-2500 J/KG) AND ABUNDANT MOISTURE (PW VALUE HAVING REBOUNDED THIS AFTERNOON TO 1-8-2.0 IN.) HAVE LED TO SCATTERED STORMS... MORE NUMEROUS IN THE SOUTHEAST CWA AS DEPICTED WELL BY EARLIER FORECASTS AND RECENT HRRR MODEL RUNS. DEEP LAYER BULK SHEAR IS QUITE WEAK THOUGH WITH MARGINAL D-CAPE... SO ANY PARTICULARLY STRONG STORMS SHOULD REMAIN ISOLATED... BUT MIXED-PHASE CAPE AROUND 700 J/KG AND INCREASING MOISTURE IN THE -10C TO -30C LAYER ACCORDING TO RAP FORECAST SOUNDINGS SUGGESTS A THREAT OF SMALL HAIL WITH ANY STRONG CELL... AND CERTAINLY LOCALLY HEAVY DOWNPOURS REMAIN A CONCERN GIVEN THE SLOW MOVEMENT AND INCREASING PW. LOSS OF HEATING AS WELL AS THE PASSAGE OF THE WEAK WAVE EAST OF THE AREA SHOULD BRING A GRADUAL DISSIPATION OF CONVECTION BY CLOSE TO MIDNIGHT. FOLLOWING PERSISTENCE WITH NO SIGNIFICANT CHANGE IN AIR MASS... REDEVELOPMENT OF STRATUS IS ANTICIPATED ACROSS THE AREA LATE TONIGHT... WITH A LINGERING THREAT OF ISOLATED SHALLOW SHOWERS MAINLY IN THE SOUTH AND EAST WHERE ABUNDANT LOW LEVEL MOISTURE PERSISTS. LOWS CLOSE TO LAST NIGHT... 70-74. -GIH && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 240 PM TUESDAY... FOR WEDNESDAY/WEDNESDAY NIGHT: LOOKS LIKE MORE OF THE SAME... WITH A CONTINUED HUMID AIR MASS AND MOIST COLUMN FEATURING PW VALUES OF 1.7-1.9 INCHES IN THE MORNING CLIMBING TO 1.9-2.1 INCHES IN THE AFTERNOON... HIGHEST EAST. WEAK LEE SURFACE TROUGHING HOLDS IN PLACE WITH A CONTINUATION OF LIGHT BREEZES FROM THE SW... WHILE IN THE MID LEVELS... VERY WEAK FLOW FROM THE WNW NEAR THE ILL-DEFINED SHEAR AXIS ALOFT WILL ALLOW FOR LITTLE TO NO DYNAMIC FORCING FOR ASCENT THROUGH THE AFTERNOON... ALTHOUGH THIS FLOW DOES INCREASE SLIGHTLY IN THE EVENING AND OVERNIGHT HOURS AS A STRONG WAVE DIGS INTO THE MEAN TROUGH OVER THE GREAT LAKES. MLCAPE ONCE AGAIN SHOULD TOP OUT AROUND 1500-2500 J/KG BUT WITH CONTINUED LOW DEEP-LAYER BULK SHEAR OF JUST 10-15 KTS... SO EXPECT ANOTHER ROUND OF SCATTERED STORMS WITH DESTABILIZATION... WITH HIGHEST POPS IN THE WRN CWA WHERE THE SREF INDICATES THE BEST CHANCE OF MEASURABLE RAIN... BUT ANY STORMS SHOULD HOLD BELOW SEVERE LIMITS. WILL RETAIN A MENTION OF ISOLATED SHOWERS OVERNIGHT WITH THE IMPROVING FLOW ALOFT AND LINGERING LOW LEVEL MOISTURE. HIGHS 86-90 AND LOWS AGAIN 70-74. -GIH && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 255 PM TUESDAY... THE OVERALL PATTERN FOR THE LONG TERM WILL BE DOMINATED BY A DEEPENING UPPER LEVEL TROUGH WITH ITS AXIS DIGGING TOWARDS THE EAST COAST. AT THE SURFACE COASTAL NORTH CAROLINA WILL BE SANDWICHED BETWEEN A STRENGTHENING SURFACE HIGH THAT WILL MOVE FROM THE GREAT PLAINS TO THE GREAT LAKES AND THE SLOWLY RETREATING BERMUDA HIGH IN THE SOUTHWESTERN ATLANTIC. IN BETWEEN A SURFACE LOW MOVING ACROSS CENTRAL ONTARIO AND QUEBEC WILL SET UP A FRONTAL ZONE THAT WILL EXTEND DOWN THE EASTERN SEABOARD...EVENTUALLY STALL OUT AND THEN POTENTIALLY RETROGRADE NEAR THE END OF THE PERIOD. TOWARDS THE END OF THE PERIOD THE X FACTOR WILL BE THE DEVELOPMENT AND TRACK OF TROPICAL STORM CHANTAL. THURSDAY AND FRIDAY: STARTING ON THURSDAY THE FRONTAL ZONE WILL BE DRAPED ACROSS THE WESTERN PIEDMONT WHICH IS WHERE THE HIGHEST PRECIPITATION CHANCES WILL BE. WITH PW VALUES IN EXCESS OF 2 INCHES. CONVECTION FEATURING HEAVY RAIN IS PROBABLE WITH THE LEE TROUGH AND DIFFERENTIAL HEATING BOUNDARIES THE MAIN FOCI FOR CONVECTION. WILL KEEP HIGHEST POPS IN THE NW THURSDAY AFTERNOON BUT OVERSPREADING THE ENTIRE CWA BY THURSDAY NIGHT. BY FRIDAY MORNING THE FOCUS FOR CONVECTION WILL SHIFT FURTHER EAST AS THE SURFACE HIGH OVER THE GREAT LAKES BUILDS INTO THE 1020S AND THE BERMUDA HIGH WEAKENS SLIGHTLY. ONCE REACHING THE COASTAL PLAIN THE FRONT WILL SLOW AND BECOME STAGNANT KEEPING THE BEST CHANCE FOR RAIN IN THE SOUTHEAST ON FRIDAY WHERE PW VALUES WILL REMAIN ABOVE 2 INCHES. BACK TOWARDS THE TRIANGLE PWS WILL DROP TO ABOUT 1.5 INCHES AND COVERAGE AND INTENSITY OF PRECIPITATION SHOULD WANE. QPF WILL BE TRICKY ONCE AGAIN AS CONVECTION WILL BE LOCALLY HEAVIER. FOR NOW WILL GO WITH ABOUT AN INCH FOR THESE TWO DAYS COMBINED WITH SOME LOCALES POTENTIALLY SEEING 2-3 INCHES IN HEAVIER AND TRAINING STORMS. STORM TOTAL QPF SHOULD BE GREATER IN THE SOUTHEAST AND DECREASING BACK TOWARDS THE TRIAD. MAX TEMPERATURES THESE TWO DAYS WILL BE IN THE MID TO UPPER 80S WITH LOWS IN THE LOWER 70S AND POTENTIALLY SOME UPPER 60S IN THE NORTHWEST ON FRIDAY NIGHT INTO SATURDAY MORNING AS THE FRONT PUSHES EASTWARD. DEWPOINTS WILL BE DEPENDENT UPON LOCATION WITH LOWER 70S COMMON AHEAD OF THE FRONT AND UPPER 60S BEHIND IT. SATURDAY AND SUNDAY: THE HIGH TO THE NORTH WILL CONTINUE TO STRENGTHEN KEEPING THE FRONTAL ZONE RESTRICTED TO THE COAST AS A CUT OFF MESO LOW OFF OF THE NEW ENGLAND COAST WILL TAKE OVER FOR THE PARENT LOW AND CONTINUE QUICKLY OFF TO THE NORTHEAST. THIS WILL BEGIN TO WASH OUT THE FRONT A LITTLE. IN ADDITION THE HIGH WILL BUILD DOWN FROM THE NORTH CAUSING THE FRONTAL ZONE TO TAKE A MORE WEST TO EAST ORIENTATION. BEST CHANCES FOR PRECIP WILL BE IN THE SOUTH AND EAST WITH DRIER CONDITIONS TO THE NW. ON SUNDAY WHATS LEFT OF THE FRONT WILL START TO RETROGRADE BACK OVER THE CWA WITH NEW MOISTURE TRANSPORT REINFORCEMENTS FROM TROPICAL STORM CHANTAL OR WHATEVER THE REMNANTS MAY BE AT THAT TIME. PW VALUES WILL ONCE AGAIN APPROACH 2 INCHES IN THE SOUTHERN HALF OF THE CWA. HIGHS ONCE AGAIN IN THE MID TO UPPER 80S WITH LOWS UPPER 60S TO LOW 70S. MONDAY AND TUESDAY: THIS PERIOD REMAINS LOW CONFIDENCE BECAUSE OF THE UNCERTAINTY IN THE LOCATION AND STRENGTH OF CHANTAL AT THIS TIME. THE BERMUDA HIGH WILL BEGIN TO MOVE BACK WESTWARD WHICH WILL HELP TO FUNNEL MOISTURE IN FROM THE ATLANTIC. WILL KEEP CHANCE POPS THROUGH THE PERIOD WITH HIGHEST CHANCES IN THE SOUTHEAST. TEMPS WILL REMAIN MID TO UPPER 80S AND LOWS UPPER 60S TO LOW 70S. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 800 PM TUESDAY... THE COVERAGE OF SHOWERS AND STORMS HAS DECREASED SIGNIFICANTLY SINCE 23Z...WITH ONLY A FEW CELLS TO THE SOUTH OF KGSO/KINT. RADAR TRENDS SUGGEST SHOWERS WILL REMAIN TO THE SOUTH...SO TAFS WILL BE VFR THROUGH 08Z...WHEN STRATUS (MOSTLY IFR) IS EXPECTED TO DEVELOP. A LIGHT SOUTHERLY WIND WILL PREVAIL. STRATUS WILL LINGER THROUGH THE MORNING HOURS BEFORE LIFTING AND SCATTERING...WITH VFR CONDITIONS EXPECTED BY 15Z. THE PERSISTENT WEATHER PATTERN SHOULD AGAIN LEAD TO SCATTERED SHOWERS AND STORMS ON WEDNESDAY AFTERNOON...WITH GREATER COVERAGE OVER THE WESTERN PIEDMONT. OUTLOOK... AFTER STORMS DIMINISH WEDNESDAY EVENING...A PERIOD OF STRATUS IS EXPECTED TO FORM AGAIN BY THURSDAY MORNING. THEN... AN APPROACHING UPPER TROUGH AND COLD FRONT WILL BRING NUMEROUS SHOWERS AND STORMS THURSDAY AND THURSDAY NIGHT. THE FRONT IS EXPECTED TO STALL ALONG THE EASTERN SEABOARD THROUGH THE WEEKEND...WHILE A MOIST SOUTHEASTERLY FLOW BRING AN EXTENDED PERIODS OF PRECIP AND ADVERSE AVIATION CONDITIONS THROUGH THE WEEKEND. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...HARTFIELD LONG TERM...ELLIS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
354 PM CDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 THE MAIN FORECAST ISSUE DURING THE SHORT TERM IS STORM COVERAGE/TIMING/SEVERITY THROUGH TONIGHT. SCATTERED STORMS ARE EXPECTED TO DEVELOP AND/OR MOVE INTO THE WEST LATE THIS AFTERNOON. MORE FAVORABLE DEEP LAYER SHEAR IS CONFINED TO THE WEST THROUGH LATE AFTERNOON. SOME ISOLATED SEVERE STORMS ARE POSSIBLE...WITH LARGE HAIL THE MAIN THREAT. THE HRRR IS STILL FOCUSING ON THE SOUTHWEST FOR INITIATION...WHILE THE 12Z WRF FOCUSES ON A FRONT STRETCHING FROM WEST CENTRAL INTO NORTH CENTRAL NORTH DAKOTA. WILL CONTINUE TO MONITOR CLOSELY FOR INITIATION. AN INTENSE SUPERCELL IS MOVING THROUGH NORTHEAST MONTANA...AND WOULD IMPACT THE FORECAST AREA AFTER 00Z IF IT HOLDS TOGETHER. A BIGGER CONCERN WILL BE A THUNDERSTORM COMPLEX THAT WILL LIKELY TRACK FROM WEST TO EAST ACROSS THE FORECAST AREA AFTER AROUND 9 PM CDT. DAMAGING STRAIGHT LINE WINDS WILL BE THE BIGGEST THREAT. FAST STORM MOTIONS SHOULD PRECLUDE WIDESPREAD FLASH FLOODING. A MULTI- MEDIA WEATHER BRIEFING HAS BEEN POSTED AT WWW.WEATHER.GOV/BIS. THE SEVERE THREAT MAY PERSIST AFTER MIDNIGHT TONIGHT BEFORE STORMS WEAKEN. ADDITIONAL NON-SEVERE STORMS WILL BE LIKELY THROUGH AT LEAST MIDDAY TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 MAIN HIGHLIGHT FOR THE LONG TERM IS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ENTERING NORTHERN PLAINS THURSDAY/FRIDAY. THE PERSISTENT HIGH AMPLITUDE RIDGING TO THE WEST WILL CONTINUE TO BE BOMBARDED BY SHORTWAVE TROUGHS DIVING DOWN OUT OF WESTERN CANADA. THIS WILL FORCE THE RIDGE TO TRANSLATE EASTWARD OVER THE CENTRAL STATES. THIS WILL IN TURN ALLOW NORTH DAKOTA TO BE INFLUENCED BY SOUTHWESTERLY FLOW AND LEE CYCLOGENESIS. BOTH THE 12 UTC ECMWF AND THE 12 UTC GFS BOTH HAVE A SHORTWAVE TROUGH DRAPED ACROSS THE NORTHERN PLAINS AND SURFACE LOW OVER NORTHWESTERN SOUTH DAKOTA EARLY FRIDAY MORNING. THIS WILL ALLOW FOR MOIST SOUTHERLY FLOW AHEAD OF THE COLD FRONT. WITH INCREASING MOISTURE...SURFACE LOW PRESSURE...AND UPPER LEVEL DIFFLUENCE WIDESPREAD THUNDERSTORM DEVELOPMENT IS POSSIBLE FRIDAY AFTERNOON AND EVENING. IN ADDITION TO THOSE INGREDIENTS THE 12 UTC ECMWF IS FORECASTING 50+ KNOTS OF 0-6 KM SHEAR...2000+ MUCAPE...AND DEW POINTS IN THE MID TO UPPER 60S. IF THIS VERIFIES...SEVERE WEATHER IS POSSIBLE FRIDAY AFTERNOON AND EVENING. OTHERWISE...THE EXTENDED PERIOD LOOKS ACTIVE WITH CHANCES FOR PRECIP THROUGHOUT THE PERIOD AS SHORTWAVES RIDE ALONG THE NORTHERN PERIPHERY OF THE RIDGE TO OUR SOUTH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 341 PM CDT MON JUL 8 2013 THE MAIN FOCUS THROUGH THE TAF PERIOD IS THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. SCATTERED STORMS ARE EXPECTED THIS AFTERNOON THROUGH EARLY EVENING...BUT TOUGH TO PINPOINT FAVORED AREA FOR DEVELOPMENT AND TIMING. LATER TONIGHT...AFTER 02Z...ENHANCED WINDS WILL BE POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM...AJ AVIATION...RPK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
118 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 1258 PM CDT MON JUL 8 2013 UPDATE MAINLY FOR HOURLY POPS THIS AFTERNOON AND TONIGHT. SCATTERED STORMS ARE EXPECTED TO DEVELOP ACROSS THE WEST AND PERHAPS INTO CENTRAL COUNTIES THIS AFTERNOON. MORE FAVORABLE DEEP LAYER SHEAR WILL BE CONFINED TO THE WEST THROUGH LATE AFTERNOON. SOME ISOLATED SEVERE STORMS ARE POSSIBLE...WITH LARGE HAIL THE MAIN THREAT. THE HRRR IS FOCUSING ON THE SOUTHWEST FOR INITIATION...WHILE THE 12Z WRF FOCUSES ON A FRONT STRETCHING FROM WEST CENTRAL INTO NORTH CENTRAL NORTH DAKOTA. EITHER LOCATION IS PLAUSIBLE. THE BIGGER CONCERN WILL BE A THUNDERSTORM COMPLEX THAT WILL LIKELY TRACK FROM WEST TO EAST ACROSS THE FORECAST AREA AFTER AROUND 9 PM CDT. DAMAGING STRAIGHT LINE WINDS WILL BE THE BIGGEST THREAT. FAST STORM MOTIONS SHOULD PRECLUDE WIDESPREAD FLASH FLOODING. WILL HAVE AN UPDATED MULTI-MEDIA WEATHER BRIEFING UP SHORTLY AT WWW.WEATHER.GOV/BIS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 325 AM CDT MON JUL 8 2013 THE MAIN CONCERN IN THE SHORT TERM WILL BE THE CHANCE OF THUNDERSTORMS...SOME POSSIBLY SEVERE. EARLY MORNING RADAR MOSAIC SHOWS THUNDERSTORMS MOVING ACROSS NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA. THE HRRR CAPTURES THIS ACTIVITY AND MOVES IT INTO THE NORTH CENTRAL PART OF THE STATE LATER THIS MORNING. MUCAPE FROM THE SPC MESOSCALE ANALYSIS PAGE SHOWS VALUES NEAR 1000 J/KG THIS MORNING ACROSS NORTHWEST / NORTH CENTRAL NORTH DAKOTA...SO AN ISOLATED STRONG STORM IS POSSIBLE. ATTENTION THIS AFTERNOON SHIFTS TO A BOUNDARY THAT IS EXPECTED TO BECOME ESTABLISHED FROM SOUTHWEST NORTH DAKOTA INTO THE NORTH CENTRAL PART OF THE STATE. THE LATEST RAP SHOWS CONVECTION DEVELOPING ALONG THE BOUNDARY BY EARLY AFTERNOON. THERE WILL BE GOOD INSTABILITY IN PLACE WITH MLCAPE VALUES OF 1500-2500 J/KG...AND DEEP LAYER SHEAR OF 40 KTS SHOULD SUPPORT SUPERCELLS. THE MAIN THREATS ARE EXPECTED TO BE LARGE HAIL AND DAMAGING WINDS...THOUGH AN ISOLATED TORNADO IS ALSO POSSIBLE. LATER TONIGHT...A STRONG H5 WAVE IS EXPECTED TO MOVE ACROSS MONTANA INTO NORTH DAKOTA. THIS WILL HELP INCREASE THUNDERSTORM COVERAGE...WITH THE POTENTIAL DEVELOPMENT OF AN EASTWARD PROPAGATING MCS. THIS WILL GRADUALLY SHIFT THE PRIMARY THUNDERSTORM THREATS TO DAMAGING WINDS AND HEAVY RAIN LATER TONIGHT. SEE THE HYDRO SECTION BELOW WHICH DISCUSSES THE HEAVY RAIN POTENTIAL. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 AM CDT MON JUL 8 2013 THE CHALLENGE IN THE EXTENDED WILL BE ENDING THE PRECIPITATION CHANCES TUESDAY AS THE SHORTWAVE EXITS THE REGION. BELIEVE RESIDUAL SHOWERS AND THUNDERSTORMS WILL BE IN THE NORTH AND EAST TUESDAY MORNING...WITH ONLY A SLIGHT CHANCE SOUTH. THE PRECIPITATION WILL LIKELY BE EXITING THE REGION BY EARLY AFTERNOON...SO BY EVENING TUESDAY IT SHOULD BE DRY ACROSS THE REGION. THIS WILL BE FOLLOWED BY A RELATIVELY QUIET PERIOD WEDNESDAY AND THURSDAY AS AN H500 RIDGE BUILDS INTO THE REGION. HOWEVER...MUCH WARMER TEMPERATURES ASSOCIATED WITH THE RIDGE WILL ALSO ARRIVE IN THE WEST ON THURSDAY AND CONTINUE INTO FRIDAY. BOTH GFS AND ECMWF MODELS SUPPORT THIS SCENARIO. EXPECT HIGH TEMPERATURES WEDNESDAY INTO THE LOW TO MIDDLE 90S WEST...UPPER 80S TO AROUND 90 CENTRAL. AS THE RIDGE MOVES EAST ON FRIDAY INTO THE WEEKEND...WILL BE PICKING UP MORE CHANCES FOR THUNDERSTORMS AS SHORTWAVE ENERGY WILL AGAIN BE MOVING THROUGH THE NORTHERN PLAINS. THAT BEING 5 TO 7 DAYS OUT...AND WITH MODELS DIFFERING IN THE FLOW ALOFT...JUST MENTIONED SLIGHT CHANCE FOR THUNDERSTORMS FRIDAY INTO WEEKEND. GFS HAS BUILDING HEIGHTS FOR THIS PERIOD ALOFT WHILE THE EUROPEAN IS MORE ACTIVE WITH SHORTWAVE ENERGY MOVING THROUGH....ALTHOUGH BOTH MODELS WOULD SUPPORT SOME THUNDERSTORMS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1258 PM CDT MON JUL 8 2013 THE MAIN FOCUS THROUGH THE TAF PERIOD IS THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. SCATTERED STORMS ARE EXPECTED THIS AFTERNOON THROUGH EARLY EVENING...BUT TOUGH TO PINPOINT FAVORED AREA FOR DEVELOPMENT AND TIMING. LATER TONIGHT...AFTER 02Z...ENHANCED WINDS WILL BE POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .HYDROLOGY... ISSUED AT 325 AM CDT MON JUL 8 2013 HEAVY RAIN IS POSSIBLE WITH MULTIPLE ROUNDS OF THUNDERSTORMS TODAY INTO TONIGHT. PRECIPITABLE WATER VALUES AROUND 1.5 INCHES ARE EXPECTED TONIGHT ACROSS MUCH OF THE FORECAST AREA. THE HEAVIEST RAIN POTENTIAL APPEARS TO BE ALONG AND NORTH OF HIGHWAY 200...WHERE AN EASTWARD PROPAGATING THUNDERSTORM COMPLEX IS POSSIBLE. 1 HOUR FLASH FLOOD GUIDANCE VALUES ARE AT LEAST 1.5 INCHES...AND 3 HOUR VALUES ARE GENERALLY IN THE 1.5 - 3.0 INCH RANGE. DECIDED TO HOLD OFF ON ANY FLASH FLOOD WATCHES FOR NOW DUE TO THE RELATIVELY HIGH FLASH FLOOD GUIDANCE VALUES AND EXPECTED PROGRESSIVE STORM MOTIONS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM/HYDROLOGY...CK LONG TERM...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1250 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 1242 PM CDT MON JUL 8 2013 ISOLD SHRA HAVE PRETTY MUCH DISSIPATED OR MOVED OUT OF FORECAST AREA WITH DEPARTING WAVE. WEAK BOUNDARY REMAINS IN PLACE ACROSS N CENTRAL INTO PARTS OF NE ND HOWEVER CAPE AND INSTABILITY WEAK. KEPT SOME LOW POPS ALONG BOUNDARY HOWEVER CONFIDENCE LOW ON ANY OTHER CONVECTION DEVELOPING REMAINDER OF AFTERNOON SO TRIMMED POPS ACCORDINGLY ELSEWHERE. WITH CLOUDS LINGERING LONGER OVER THE NW FA DID LOWER TEMPERATURES SLIGHTLY OTHERWISE TEMPERATURES LOOKING OK. UPDATE ISSUED AT 931 AM CDT MON JUL 8 2013 SHORTWAVE RIDING ALONG INTERNATIONAL BORDER AND WEAK SURFACE BOUNDARY JUST NORTH OF HIGHWAY 2 ENOUGH TO SUSTAIN ISOLD CONVECTION PROPAGATING INTO FAR WESTERN FA WEST OF DVL. CELLS WEAKENING AND SHORT RANGE MESOSCALE MODELS GENERALLY DISSIPATE CONVECTION BY NOON. TRIMMED BACK ON POPS TO COVER JUST THE FAR WEST AND IF TRENDS CONTINUE WILL LIKELY BE ABLE TO PULL POPS REST OF TODAY. ADJUSTED SKY CONDITION OTHERWISE NO OTHER CHANGES FOR THIS UPDATE PERIOD. UPDATE ISSUED AT 643 AM CDT MON JUL 8 2013 STORMS OVER NORTHWESTERN ND HAVE BEEN HOLDING A BIT BETTER THAN EXPECTED. IN ADDITION...LATEST RUNS OF THE RAP HAVE A FEW REMNANTS OF CONVECTION REACHING THE FAR NORTHWESTERN CWA THIS MORNING. THUS...INCLUDED SOME 20 POPS IN THAT AREA STARTING AT 15Z. OTHERWISE...THINK THAT MORE SIGNIFICANT ACTIVITY WILL HOLD OFF UNTIL TONIGHT SO WILL KEEP HIGHEST POPS FOR THAT TIME PERIOD. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 302 AM CDT MON JUL 8 2013 CONVECTION TIMING WILL BE THE MAIN HEADACHE FOR THE SHORT TERM. WV LOOP SHOWS NEAR ZONAL FLOW OVER THE NORTHERN PLAINS...WITH VARIOUS WEAK SHORTWAVES APPROACHING FROM THE WEST. WEAK SFC HIGH PRESSURE REMAINS IN PLACE OVER THE CWA...AND MODELS ARE IN FAIRLY GOOD AGREEMENT ON IT MOVING TO THE EAST TODAY AS LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES. SPC MESOANALYSIS HAS THE CWA UNDER A RELATIVELY STABLE AND DRIER AIRMASS THAN THE SURROUNDING AREAS. WILL HAVE TO MONITOR CONVECTION CURRENTLY ENTERING FAR NORTHWESTERN ND. AT THIS POINT IT SEEMS LIKE IT WILL DISSIPATE BEFORE APPROACHING OUR CWA LATER THIS MORNING WHICH THE RAP...GFS...ECMWF...AND GEM SHOW. A FEW OF THE MODELS SUCH AS NAM AND HRR HOWEVER HAVE IT HOLDING TOGETHER ENOUGH TO ENTER THE DEVILS LAKE BASIN LATER ON THIS MORNING. AT THIS POINT THINK THE STORMS WILL OUTRUN THEIR SUPPLY OF ELEVATED INSTABILITY AND DIE OUT BUT WILL KEEP AN EYE ON RADAR TRENDS BEFORE SENDING EVERYTHING OUT. JUST HAVE SOME LOW POPS IN THE FAR WEST THIS AFTERNOON BETWEEN 18-00Z FOR ANYTHING DRIFTING INTO THE AREA FROM CENTRAL ND. THINK THAT THE MAIN THREAT WILL BE LATER TONIGHT AS A MORE SIGNIFICANT UPPER SHORTWAVE COMES OUT INTO THE NORTHERN PLAINS. THE SFC LOW WILL MOVE OUT INTO THE EASTERN DAKOTAS...AND THERE SHOULD BE A GOOD AMOUNT OF BULK SHEAR TO WORK WITH AS THE SYSTEM COMES OUT. SOME OF THE MODELS SHOW MORE THAN 1500 J/KG OF CAPE IN THE WESTERN CWA...BUT OTHERS HAVE ONLY SOME LIMITED ELEVATED CAPE THIS EVENING. THE GFS HAS A STRONGER CONVECTIVE COMPLEX OVER SD WHILE THE NORTHERN ACTIVITY IS A BIT LESS. ON THE OTHER HAND...THINK THERE COULD BE ENOUGH INSTABILITY TO GET STORMS GOING OVER WESTERN ND THIS AFTERNOON AND THEN COME EASTWARD AS AN MCS LATER TONIGHT. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND WILL MENTION HAIL AND DAMAGING WIND THREAT IN THE HWO. HOW TUESDAY PLAYS OUT WILL DEPEND SOMEWHAT ON HOW CONVECTION BEHAVES TONIGHT. THE UPPER SHORTWAVE TROUGH WILL MOVE INTO THE CWA...BUT THE SFC LOW WILL BE WELL TO OUR SOUTHEAST AND THE COLD FRONT MAY BE THROUGH MOST OF THE CWA BY PEAK HEATING. WILL CONTINUE TO KEEP POPS FAIRLY HIGH BUT THE COLDER AIR BUILDING IN AS WELL AS ANY CONVECTIVE DEBRIS FROM EARLY MORNING ACTIVITY COULD PUT A DAMPER ON ANY STRONGER STORMS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 302 AM CDT MON JUL 8 2013 TUESDAY NIGHT THROUGH WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH NORTHWESTERLY FLOW ALOFT AND SFC HIGH PRESSURE OVER THE AREA. COLD AIR ADVECTION BEHIND THE EARLY WEEK SYSTEM SHOULD KNOCK BACK TEMPS A BIT. HIGHS ON WEDNESDAY WILL BE IN THE 70S TO LOW 80S WITH LOWS MAINLY IN THE 50S. THURSDAY-SUNDAY...THE UPPER RIDGE WILL AMPLIFY ACROSS THE ROCKIES AND HIGH PLAINS ON THURSDAY. RETURN FLOW WILL ENSUE AS THE SFC HIGH DRIFTS EAST TOWARDS THE WESTERN GREAT LAKES. 925 MB WARM A BIT FROM WEDNESDAY...WHICH SHOULD ALLOW TEMPS TO RISE INTO THE LOW TO MID 80S. THE 00Z GFS/ECMWF INDICATE A STRONGER UPPER WAVE/JET STREAK PROPAGATING INTO CENTRAL CANADA ON FRIDAY...DRAGGING A SFC BOUNDARY INTO THE REGION...AND PROVIDING SOME POSSIBLE FOCUS FOR CONVECTION FRI/FRI NIGHT. KEPT HIGH TEMPS ON FRIDAY IN THE LOW TO MID 80S. THE ECMWF NOSES THE THERMAL RIDGE ACROSS THE AREA AHEAD OF THE FRONT...AND WOULD SUGGEST A BIT WARMER TEMPS...BUT MUCH WILL DEPEND ON THE TIMING OF THE WAVE AND ORIENTATION OF THE FLOW FIELDS. FORECAST CONFIDENCE IS LOW FOR NEXT WEEKEND. BOTH THE GFS/ECMWF KEEP THE UPPER RIDGE ANCHORED ACROSS THE SOUTHERN/CENTRAL PLAINS...WITH MORE ZONAL FLOW ACROSS THE NORTHERN PLAINS AS EMBEDDED SHORTWAVES HELP TO FLATTEN THE RIDGE. THERE ARE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF IN THE POSITION OF SURFACE AND UPPER FEATURES...WITH THE ECMWF THE COOLER AND MORE PROGRESSIVE SOLUTION. AS SUCH...WILL CONTINUE TO MENTION LOW POPS WITH FAIRLY SEASONABLE TEMPS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1242 PM CDT MON JUL 8 2013 THE MAIN CHALLENGE WILL BE INCREASING CHANCES FOR SHOWERS AND STORMS FROM WEST TO EAST LATE TONIGHT INTO TUE MORNING. WILL MENTION SOME -TSRA IN THE WEST LATER TONIGHT...AND IN THE EAST TUE MORNING. WINDS SHOULD REMAIN SOUTHERLY TONIGHT BEFORE SHIFTING TO THE N/NW LATE TONIGHT AND TUE MORNING. WINDS COULD BE LOCALLY GUSTY WITH STRONG WINDS POSSIBLE WITH A THUNDERSTORM COMPLEX LATE TONIGHT/TUE...BUT WON/T MENTION ANY HIGHER GUSTS YET. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...JR LONG TERM...JR/MAKOWSKI AVIATION...DK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1024 AM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 1015 AM CDT MON JUL 8 2013 UPDATE MAINLY TO FINE TUNE POPS THROUGH LATE MORNING AND AFTERNOON. ISOLATED SHOWERS AND STORMS HAVE EXITED THE NORTHEAST THIS MORNING. STORMS EXPECTED TO REDEVELOP EARLY TO MID AFTERNOON...MAINLY WEST NEAR A STATIONARY FRONT. ANY STORMS THAT DEVELOP THIS AFTERNOON COULD BECOME SEVERE QUICKLY. A LARGE THUNDERSTORM COMPLEX IS EXPECTED TO ROLL ACROSS THE STATE LATER TONIGHT...WITH THREATS OF DAMAGING STRAIGHT LINE WINDS AND VERY HEAVY RAIN. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 325 AM CDT MON JUL 8 2013 THE MAIN CONCERN IN THE SHORT TERM WILL BE THE CHANCE OF THUNDERSTORMS...SOME POSSIBLY SEVERE. EARLY MORNING RADAR MOSAIC SHOWS THUNDERSTORMS MOVING ACROSS NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA. THE HRRR CAPTURES THIS ACTIVITY AND MOVES IT INTO THE NORTH CENTRAL PART OF THE STATE LATER THIS MORNING. MUCAPE FROM THE SPC MESOSCALE ANALYSIS PAGE SHOWS VALUES NEAR 1000 J/KG THIS MORNING ACROSS NORTHWEST / NORTH CENTRAL NORTH DAKOTA...SO AN ISOLATED STRONG STORM IS POSSIBLE. ATTENTION THIS AFTERNOON SHIFTS TO A BOUNDARY THAT IS EXPECTED TO BECOME ESTABLISHED FROM SOUTHWEST NORTH DAKOTA INTO THE NORTH CENTRAL PART OF THE STATE. THE LATEST RAP SHOWS CONVECTION DEVELOPING ALONG THE BOUNDARY BY EARLY AFTERNOON. THERE WILL BE GOOD INSTABILITY IN PLACE WITH MLCAPE VALUES OF 1500-2500 J/KG...AND DEEP LAYER SHEAR OF 40 KTS SHOULD SUPPORT SUPERCELLS. THE MAIN THREATS ARE EXPECTED TO BE LARGE HAIL AND DAMAGING WINDS...THOUGH AN ISOLATED TORNADO IS ALSO POSSIBLE. LATER TONIGHT...A STRONG H5 WAVE IS EXPECTED TO MOVE ACROSS MONTANA INTO NORTH DAKOTA. THIS WILL HELP INCREASE THUNDERSTORM COVERAGE...WITH THE POTENTIAL DEVELOPMENT OF AN EASTWARD PROPAGATING MCS. THIS WILL GRADUALLY SHIFT THE PRIMARY THUNDERSTORM THREATS TO DAMAGING WINDS AND HEAVY RAIN LATER TONIGHT. SEE THE HYDRO SECTION BELOW WHICH DISCUSSES THE HEAVY RAIN POTENTIAL. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 AM CDT MON JUL 8 2013 THE CHALLENGE IN THE EXTENDED WILL BE ENDING THE PRECIPITATION CHANCES TUESDAY AS THE SHORTWAVE EXITS THE REGION. BELIEVE RESIDUAL SHOWERS AND THUNDERSTORMS WILL BE IN THE NORTH AND EAST TUESDAY MORNING...WITH ONLY A SLIGHT CHANCE SOUTH. THE PRECIPITATION WILL LIKELY BE EXITING THE REGION BY EARLY AFTERNOON...SO BY EVENING TUESDAY IT SHOULD BE DRY ACROSS THE REGION. THIS WILL BE FOLLOWED BY A RELATIVELY QUIET PERIOD WEDNESDAY AND THURSDAY AS AN H500 RIDGE BUILDS INTO THE REGION. HOWEVER...MUCH WARMER TEMPERATURES ASSOCIATED WITH THE RIDGE WILL ALSO ARRIVE IN THE WEST ON THURSDAY AND CONTINUE INTO FRIDAY. BOTH GFS AND ECMWF MODELS SUPPORT THIS SCENARIO. EXPECT HIGH TEMPERATURES WEDNESDAY INTO THE LOW TO MIDDLE 90S WEST...UPPER 80S TO AROUND 90 CENTRAL. AS THE RIDGE MOVES EAST ON FRIDAY INTO THE WEEKEND...WILL BE PICKING UP MORE CHANCES FOR THUNDERSTORMS AS SHORTWAVE ENERGY WILL AGAIN BE MOVING THROUGH THE NORTHERN PLAINS. THAT BEING 5 TO 7 DAYS OUT...AND WITH MODELS DIFFERING IN THE FLOW ALOFT...JUST MENTIONED SLIGHT CHANCE FOR THUNDERSTORMS FRIDAY INTO WEEKEND. GFS HAS BUILDING HEIGHTS FOR THIS PERIOD ALOFT WHILE THE EUROPEAN IS MORE ACTIVE WITH SHORTWAVE ENERGY MOVING THROUGH....ALTHOUGH BOTH MODELS WOULD SUPPORT SOME THUNDERSTORMS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1015 AM CDT MON JUL 8 2013 MAIN HAZARDS TO AVIATION THIS FORECAST PERIOD MAINLY THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. BEST ESTIMATE FOR THUNDERSTORM TIMING IS BETWEEN 00Z- 12Z TONIGHT. ENHANCED WINDS POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .HYDROLOGY... ISSUED AT 325 AM CDT MON JUL 8 2013 HEAVY RAIN IS POSSIBLE WITH MULTIPLE ROUNDS OF THUNDERSTORMS TODAY INTO TONIGHT. PRECIPITABLE WATER VALUES AROUND 1.5 INCHES ARE EXPECTED TONIGHT ACROSS MUCH OF THE FORECAST AREA. THE HEAVIEST RAIN POTENTIAL APPEARS TO BE ALONG AND NORTH OF HIGHWAY 200...WHERE AN EASTWARD PROPAGATING THUNDERSTORM COMPLEX IS POSSIBLE. 1 HOUR FLASH FLOOD GUIDANCE VALUES ARE AT LEAST 1.5 INCHES...AND 3 HOUR VALUES ARE GENERALLY IN THE 1.5 - 3.0 INCH RANGE. DECIDED TO HOLD OFF ON ANY FLASH FLOOD WATCHES FOR NOW DUE TO THE RELATIVELY HIGH FLASH FLOOD GUIDANCE VALUES AND EXPECTED PROGRESSIVE STORM MOTIONS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...RP KINNEY SHORT TERM...CK LONG TERM/AVIATION...WAA HYDROLOGY...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
936 AM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 931 AM CDT MON JUL 8 2013 SHORTWAVE RIDING ALONG INTERNATIONAL BORDER AND WEAK SURFACE BOUNDARY JUST NORTH OF HIGHWAY 2 ENOUGH TO SUSTAIN ISOLD CONVECTION PROPAGATING INTO FAR WESTERN FA WEST OF DVL. CELLS WEAKENING AND SHORT RANGE MESOSCALE MODELS GENERALLY DISSIPATE CONVECTION BY NOON. TRIMMED BACK ON POPS TO COVER JUST THE FAR WEST AND IF TRENDS CONTINUE WILL LIKELY BE ABLE TO PULL POPS REST OF TODAY. ADJUSTED SKY CONDITION OTHERWISE NO OTHER CHANGES FOR THIS UPDATE PERIOD. UPDATE ISSUED AT 643 AM CDT MON JUL 8 2013 STORMS OVER NORTHWESTERN ND HAVE BEEN HOLDING A BIT BETTER THAN EXPECTED. IN ADDITION...LATEST RUNS OF THE RAP HAVE A FEW REMNANTS OF CONVECTION REACHING THE FAR NORTHWESTERN CWA THIS MORNING. THUS...INCLUDED SOME 20 POPS IN THAT AREA STARTING AT 15Z. OTHERWISE...THINK THAT MORE SIGNIFICANT ACTIVITY WILL HOLD OFF UNTIL TONIGHT SO WILL KEEP HIGHEST POPS FOR THAT TIME PERIOD. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 302 AM CDT MON JUL 8 2013 CONVECTION TIMING WILL BE THE MAIN HEADACHE FOR THE SHORT TERM. WV LOOP SHOWS NEAR ZONAL FLOW OVER THE NORTHERN PLAINS...WITH VARIOUS WEAK SHORTWAVES APPROACHING FROM THE WEST. WEAK SFC HIGH PRESSURE REMAINS IN PLACE OVER THE CWA...AND MODELS ARE IN FAIRLY GOOD AGREEMENT ON IT MOVING TO THE EAST TODAY AS LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES. SPC MESOANALYSIS HAS THE CWA UNDER A RELATIVELY STABLE AND DRIER AIRMASS THAN THE SURROUNDING AREAS. WILL HAVE TO MONITOR CONVECTION CURRENTLY ENTERING FAR NORTHWESTERN ND. AT THIS POINT IT SEEMS LIKE IT WILL DISSIPATE BEFORE APPROACHING OUR CWA LATER THIS MORNING WHICH THE RAP...GFS...ECMWF...AND GEM SHOW. A FEW OF THE MODELS SUCH AS NAM AND HRR HOWEVER HAVE IT HOLDING TOGETHER ENOUGH TO ENTER THE DEVILS LAKE BASIN LATER ON THIS MORNING. AT THIS POINT THINK THE STORMS WILL OUTRUN THEIR SUPPLY OF ELEVATED INSTABILITY AND DIE OUT BUT WILL KEEP AN EYE ON RADAR TRENDS BEFORE SENDING EVERYTHING OUT. JUST HAVE SOME LOW POPS IN THE FAR WEST THIS AFTERNOON BETWEEN 18-00Z FOR ANYTHING DRIFTING INTO THE AREA FROM CENTRAL ND. THINK THAT THE MAIN THREAT WILL BE LATER TONIGHT AS A MORE SIGNIFICANT UPPER SHORTWAVE COMES OUT INTO THE NORTHERN PLAINS. THE SFC LOW WILL MOVE OUT INTO THE EASTERN DAKOTAS...AND THERE SHOULD BE A GOOD AMOUNT OF BULK SHEAR TO WORK WITH AS THE SYSTEM COMES OUT. SOME OF THE MODELS SHOW MORE THAN 1500 J/KG OF CAPE IN THE WESTERN CWA...BUT OTHERS HAVE ONLY SOME LIMITED ELEVATED CAPE THIS EVENING. THE GFS HAS A STRONGER CONVECTIVE COMPLEX OVER SD WHILE THE NORTHERN ACTIVITY IS A BIT LESS. ON THE OTHER HAND...THINK THERE COULD BE ENOUGH INSTABILITY TO GET STORMS GOING OVER WESTERN ND THIS AFTERNOON AND THEN COME EASTWARD AS AN MCS LATER TONIGHT. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND WILL MENTION HAIL AND DAMAGING WIND THREAT IN THE HWO. HOW TUESDAY PLAYS OUT WILL DEPEND SOMEWHAT ON HOW CONVECTION BEHAVES TONIGHT. THE UPPER SHORTWAVE TROUGH WILL MOVE INTO THE CWA...BUT THE SFC LOW WILL BE WELL TO OUR SOUTHEAST AND THE COLD FRONT MAY BE THROUGH MOST OF THE CWA BY PEAK HEATING. WILL CONTINUE TO KEEP POPS FAIRLY HIGH BUT THE COLDER AIR BUILDING IN AS WELL AS ANY CONVECTIVE DEBRIS FROM EARLY MORNING ACTIVITY COULD PUT A DAMPER ON ANY STRONGER STORMS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 302 AM CDT MON JUL 8 2013 TUESDAY NIGHT THROUGH WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH NORTHWESTERLY FLOW ALOFT AND SFC HIGH PRESSURE OVER THE AREA. COLD AIR ADVECTION BEHIND THE EARLY WEEK SYSTEM SHOULD KNOCK BACK TEMPS A BIT. HIGHS ON WEDNESDAY WILL BE IN THE 70S TO LOW 80S WITH LOWS MAINLY IN THE 50S. THURSDAY-SUNDAY...THE UPPER RIDGE WILL AMPLIFY ACROSS THE ROCKIES AND HIGH PLAINS ON THURSDAY. RETURN FLOW WILL ENSUE AS THE SFC HIGH DRIFTS EAST TOWARDS THE WESTERN GREAT LAKES. 925 MB WARM A BIT FROM WEDNESDAY...WHICH SHOULD ALLOW TEMPS TO RISE INTO THE LOW TO MID 80S. THE 00Z GFS/ECMWF INDICATE A STRONGER UPPER WAVE/JET STREAK PROPAGATING INTO CENTRAL CANADA ON FRIDAY...DRAGGING A SFC BOUNDARY INTO THE REGION...AND PROVIDING SOME POSSIBLE FOCUS FOR CONVECTION FRI/FRI NIGHT. KEPT HIGH TEMPS ON FRIDAY IN THE LOW TO MID 80S. THE ECMWF NOSES THE THERMAL RIDGE ACROSS THE AREA AHEAD OF THE FRONT...AND WOULD SUGGEST A BIT WARMER TEMPS...BUT MUCH WILL DEPEND ON THE TIMING OF THE WAVE AND ORIENTATION OF THE FLOW FIELDS. FORECAST CONFIDENCE IS LOW FOR NEXT WEEKEND. BOTH THE GFS/ECMWF KEEP THE UPPER RIDGE ANCHORED ACROSS THE SOUTHERN/CENTRAL PLAINS...WITH MORE ZONAL FLOW ACROSS THE NORTHERN PLAINS AS EMBEDDED SHORTWAVES HELP TO FLATTEN THE RIDGE. THERE ARE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF IN THE POSITION OF SURFACE AND UPPER FEATURES...WITH THE ECMWF THE COOLER AND MORE PROGRESSIVE SOLUTION. AS SUCH...WILL CONTINUE TO MENTION LOW POPS WITH FAIRLY SEASONABLE TEMPS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 643 AM CDT MON JUL 8 2013 THERE HAVE BEEN BRIEF PERIODS THIS MORNING WHEN KDVL AND KTVF WENT DOWN IN VIS...BUT WEB CAMS SHOW NO SIGNIFICANT FOGGING AND THE OBSERVATIONS HAVE IMPROVED. WILL CONTINUE TO GO WITH VFR CONDITIONS THROUGHOUT THE PERIOD. THUNDERSTORMS WILL BEGIN MOVING INTO THE FORECAST AREA TOWARDS THE END OF THE PERIOD...AROUND KDVL BEFORE 06Z TONIGHT AND TO THE SITES FURTHER EAST AFTER 06Z. WILL INCLUDE A VCTS MENTION FOR NOW DUE TO UNCERTAINTIES WITH TIMING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...JR LONG TERM...JR/MAKOWSKI AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
649 AM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 641 AM CDT MON JUL 8 2013 THIS UPDATE WILL FOCUS ON CLUSTER OF EARLY MORNING THUNDERSTORMS MOVING THROUGH THE NORTH CENTRAL. THIS ACTIVITY MOVED THROUGH MONTANA OVER NIGHT AND WILL CONTINUE FOR A FEW MORE HOURS NORTH CENTRAL SUPPORTED BY THE LOW LEVEL JET. NAM LOOKS TO GAVE A GOOD HANDLE ON THIS ACTIVITY...TRENDING IT DOWN BY NOON. SHOULD HEN WAIT FOR NEXT THUNDERSTORM DEVELOPMENT IN THE AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 325 AM CDT MON JUL 8 2013 THE MAIN CONCERN IN THE SHORT TERM WILL BE THE CHANCE OF THUNDERSTORMS...SOME POSSIBLY SEVERE. EARLY MORNING RADAR MOSAIC SHOWS THUNDERSTORMS MOVING ACROSS NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA. THE HRRR CAPTURES THIS ACTIVITY AND MOVES IT INTO THE NORTH CENTRAL PART OF THE STATE LATER THIS MORNING. MUCAPE FROM THE SPC MESOSCALE ANALYSIS PAGE SHOWS VALUES NEAR 1000 J/KG THIS MORNING ACROSS NORTHWEST / NORTH CENTRAL NORTH DAKOTA...SO AN ISOLATED STRONG STORM IS POSSIBLE. ATTENTION THIS AFTERNOON SHIFTS TO A BOUNDARY THAT IS EXPECTED TO BECOME ESTABLISHED FROM SOUTHWEST NORTH DAKOTA INTO THE NORTH CENTRAL PART OF THE STATE. THE LATEST RAP SHOWS CONVECTION DEVELOPING ALONG THE BOUNDARY BY EARLY AFTERNOON. THERE WILL BE GOOD INSTABILITY IN PLACE WITH MLCAPE VALUES OF 1500-2500 J/KG...AND DEEP LAYER SHEAR OF 40 KTS SHOULD SUPPORT SUPERCELLS. THE MAIN THREATS ARE EXPECTED TO BE LARGE HAIL AND DAMAGING WINDS...THOUGH AN ISOLATED TORNADO IS ALSO POSSIBLE. LATER TONIGHT...A STRONG H5 WAVE IS EXPECTED TO MOVE ACROSS MONTANA INTO NORTH DAKOTA. THIS WILL HELP INCREASE THUNDERSTORM COVERAGE...WITH THE POTENTIAL DEVELOPMENT OF AN EASTWARD PROPAGATING MCS. THIS WILL GRADUALLY SHIFT THE PRIMARY THUNDERSTORM THREATS TO DAMAGING WINDS AND HEAVY RAIN LATER TONIGHT. SEE THE HYDRO SECTION BELOW WHICH DISCUSSES THE HEAVY RAIN POTENTIAL. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 AM CDT MON JUL 8 2013 THE CHALLENGE IN THE EXTENDED WILL BE ENDING THE PRECIPITATION CHANCES TUESDAY AS THE SHORTWAVE EXITS THE REGION. BELIEVE RESIDUAL SHOWERS AND THUNDERSTORMS WILL BE IN THE NORTH AND EAST TUESDAY MORNING...WITH ONLY A SLIGHT CHANCE SOUTH. THE PRECIPITATION WILL LIKELY BE EXITING THE REGION BY EARLY AFTERNOON...SO BY EVENING TUESDAY IT SHOULD BE DRY ACROSS THE REGION. THIS WILL BE FOLLOWED BY A RELATIVELY QUIET PERIOD WEDNESDAY AND THURSDAY AS AN H500 RIDGE BUILDS INTO THE REGION. HOWEVER...MUCH WARMER TEMPERATURES ASSOCIATED WITH THE RIDGE WILL ALSO ARRIVE IN THE WEST ON THURSDAY AND CONTINUE INTO FRIDAY. BOTH GFS AND ECMWF MODELS SUPPORT THIS SCENARIO. EXPECT HIGH TEMPERATURES WEDNESDAY INTO THE LOW TO MIDDLE 90S WEST...UPPER 80S TO AROUND 90 CENTRAL. AS THE RIDGE MOVES EAST ON FRIDAY INTO THE WEEKEND...WILL BE PICKING UP MORE CHANCES FOR THUNDERSTORMS AS SHORTWAVE ENERGY WILL AGAIN BE MOVING THROUGH THE NORTHERN PLAINS. THAT BEING 5 TO 7 DAYS OUT...AND WITH MODELS DIFFERING IN THE FLOW ALOFT...JUST MENTIONED SLIGHT CHANCE FOR THUNDERSTORMS FRIDAY INTO WEEKEND. GFS HAS BUILDING HEIGHTS FOR THIS PERIOD ALOFT WHILE THE EUROPEAN IS MORE ACTIVE WITH SHORTWAVE ENERGY MOVING THROUGH....ALTHOUGH BOTH MODELS WOULD SUPPORT SOME THUNDERSTORMS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 641 AM CDT MON JUL 8 2013 MAIN HAZARDS TO AVIATION THIS FORECAST PERIOD MAINLY THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. EARLY MORNING LINE OF STORMS WILL MOVE THROUGH THE NORTH CENTRAL...BRUSHING BY KMOT BETWEEN 12-15Z. AFTER THAT...MUST WAIT FOR THUNDERSTORMS TO DEVELOP. BEST ESTIMATE WILL BE BETWEEN 00Z-12Z TONIGHT. ENHANCED WINDS POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .HYDROLOGY... ISSUED AT 325 AM CDT MON JUL 8 2013 HEAVY RAIN IS POSSIBLE WITH MULTIPLE ROUNDS OF THUNDERSTORMS TODAY INTO TONIGHT. PRECIPITABLE WATER VALUES AROUND 1.5 INCHES ARE EXPECTED TONIGHT ACROSS MUCH OF THE FORECAST AREA. THE HEAVIEST RAIN POTENTIAL APPEARS TO BE ALONG AND NORTH OF HIGHWAY 200...WHERE AN EASTWARD PROPAGATING MCS IS POSSIBLE. 1 HOUR FLASH FLOOD GUIDANCE VALUES ARE AT LEAST 1.5 INCHES...AND 3 HOUR VALUES ARE GENERALLY IN THE 1.5 - 3.0 INCH RANGE. DECIDED TO HOLD OFF ON ANY FLASH FLOOD WATCHES FOR NOW DUE TO THE RELATIVELY HIGH FLASH FLOOD GUIDANCE VALUES AND EXPECTED PROGRESSIVE STORM MOTIONS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...CK LONG TERM...WAA AVIATION...WAA HYDROLOGY...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
643 AM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 643 AM CDT MON JUL 8 2013 STORMS OVER NORTHWESTERN ND HAVE BEEN HOLDING A BIT BETTER THAN EXPECTED. IN ADDITION...LATEST RUNS OF THE RAP HAVE A FEW REMNANTS OF CONVECTION REACHING THE FAR NORTHWESTERN CWA THIS MORNING. THUS...INCLUDED SOME 20 POPS IN THAT AREA STARTING AT 15Z. OTHERWISE...THINK THAT MORE SIGNIFICANT ACTIVITY WILL HOLD OFF UNTIL TONIGHT SO WILL KEEP HIGHEST POPS FOR THAT TIME PERIOD. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 302 AM CDT MON JUL 8 2013 CONVECTION TIMING WILL BE THE MAIN HEADACHE FOR THE SHORT TERM. WV LOOP SHOWS NEAR ZONAL FLOW OVER THE NORTHERN PLAINS...WITH VARIOUS WEAK SHORTWAVES APPROACHING FROM THE WEST. WEAK SFC HIGH PRESSURE REMAINS IN PLACE OVER THE CWA...AND MODELS ARE IN FAIRLY GOOD AGREEMENT ON IT MOVING TO THE EAST TODAY AS LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES. SPC MESOANALYSIS HAS THE CWA UNDER A RELATIVELY STABLE AND DRIER AIRMASS THAN THE SURROUNDING AREAS. WILL HAVE TO MONITOR CONVECTION CURRENTLY ENTERING FAR NORTHWESTERN ND. AT THIS POINT IT SEEMS LIKE IT WILL DISSIPATE BEFORE APPROACHING OUR CWA LATER THIS MORNING WHICH THE RAP...GFS...ECMWF...AND GEM SHOW. A FEW OF THE MODELS SUCH AS NAM AND HRR HOWEVER HAVE IT HOLDING TOGETHER ENOUGH TO ENTER THE DEVILS LAKE BASIN LATER ON THIS MORNING. AT THIS POINT THINK THE STORMS WILL OUTRUN THEIR SUPPLY OF ELEVATED INSTABILITY AND DIE OUT BUT WILL KEEP AN EYE ON RADAR TRENDS BEFORE SENDING EVERYTHING OUT. JUST HAVE SOME LOW POPS IN THE FAR WEST THIS AFTERNOON BETWEEN 18-00Z FOR ANYTHING DRIFTING INTO THE AREA FROM CENTRAL ND. THINK THAT THE MAIN THREAT WILL BE LATER TONIGHT AS A MORE SIGNIFICANT UPPER SHORTWAVE COMES OUT INTO THE NORTHERN PLAINS. THE SFC LOW WILL MOVE OUT INTO THE EASTERN DAKOTAS...AND THERE SHOULD BE A GOOD AMOUNT OF BULK SHEAR TO WORK WITH AS THE SYSTEM COMES OUT. SOME OF THE MODELS SHOW MORE THAN 1500 J/KG OF CAPE IN THE WESTERN CWA...BUT OTHERS HAVE ONLY SOME LIMITED ELEVATED CAPE THIS EVENING. THE GFS HAS A STRONGER CONVECTIVE COMPLEX OVER SD WHILE THE NORTHERN ACTIVITY IS A BIT LESS. ON THE OTHER HAND...THINK THERE COULD BE ENOUGH INSTABILITY TO GET STORMS GOING OVER WESTERN ND THIS AFTERNOON AND THEN COME EASTWARD AS AN MCS LATER TONIGHT. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND WILL MENTION HAIL AND DAMAGING WIND THREAT IN THE HWO. HOW TUESDAY PLAYS OUT WILL DEPEND SOMEWHAT ON HOW CONVECTION BEHAVES TONIGHT. THE UPPER SHORTWAVE TROUGH WILL MOVE INTO THE CWA...BUT THE SFC LOW WILL BE WELL TO OUR SOUTHEAST AND THE COLD FRONT MAY BE THROUGH MOST OF THE CWA BY PEAK HEATING. WILL CONTINUE TO KEEP POPS FAIRLY HIGH BUT THE COLDER AIR BUILDING IN AS WELL AS ANY CONVECTIVE DEBRIS FROM EARLY MORNING ACTIVITY COULD PUT A DAMPER ON ANY STRONGER STORMS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 302 AM CDT MON JUL 8 2013 TUESDAY NIGHT THROUGH WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH NORTHWESTERLY FLOW ALOFT AND SFC HIGH PRESSURE OVER THE AREA. COLD AIR ADVECTION BEHIND THE EARLY WEEK SYSTEM SHOULD KNOCK BACK TEMPS A BIT. HIGHS ON WEDNESDAY WILL BE IN THE 70S TO LOW 80S WITH LOWS MAINLY IN THE 50S. THURSDAY-SUNDAY...THE UPPER RIDGE WILL AMPLIFY ACROSS THE ROCKIES AND HIGH PLAINS ON THURSDAY. RETURN FLOW WILL ENSUE AS THE SFC HIGH DRIFTS EAST TOWARDS THE WESTERN GREAT LAKES. 925 MB WARM A BIT FROM WEDNESDAY...WHICH SHOULD ALLOW TEMPS TO RISE INTO THE LOW TO MID 80S. THE 00Z GFS/ECMWF INDICATE A STRONGER UPPER WAVE/JET STREAK PROPAGATING INTO CENTRAL CANADA ON FRIDAY...DRAGGING A SFC BOUNDARY INTO THE REGION...AND PROVIDING SOME POSSIBLE FOCUS FOR CONVECTION FRI/FRI NIGHT. KEPT HIGH TEMPS ON FRIDAY IN THE LOW TO MID 80S. THE ECMWF NOSES THE THERMAL RIDGE ACROSS THE AREA AHEAD OF THE FRONT...AND WOULD SUGGEST A BIT WARMER TEMPS...BUT MUCH WILL DEPEND ON THE TIMING OF THE WAVE AND ORIENTATION OF THE FLOW FIELDS. FORECAST CONFIDENCE IS LOW FOR NEXT WEEKEND. BOTH THE GFS/ECMWF KEEP THE UPPER RIDGE ANCHORED ACROSS THE SOUTHERN/CENTRAL PLAINS...WITH MORE ZONAL FLOW ACROSS THE NORTHERN PLAINS AS EMBEDDED SHORTWAVES HELP TO FLATTEN THE RIDGE. THERE ARE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF IN THE POSITION OF SURFACE AND UPPER FEATURES...WITH THE ECMWF THE COOLER AND MORE PROGRESSIVE SOLUTION. AS SUCH...WILL CONTINUE TO MENTION LOW POPS WITH FAIRLY SEASONABLE TEMPS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 643 AM CDT MON JUL 8 2013 THERE HAVE BEEN BRIEF PERIODS THIS MORNING WHEN KDVL AND KTVF WENT DOWN IN VIS...BUT WEB CAMS SHOW NO SIGNIFICANT FOGGING AND THE OBSERVATIONS HAVE IMPROVED. WILL CONTINUE TO GO WITH VFR CONDITIONS THROUGHOUT THE PERIOD. THUNDERSTORMS WILL BEGIN MOVING INTO THE FORECAST AREA TOWARDS THE END OF THE PERIOD...AROUND KDVL BEFORE 06Z TONIGHT AND TO THE SITES FURTHER EAST AFTER 06Z. WILL INCLUDE A VCTS MENTION FOR NOW DUE TO UNCERTAINTIES WITH TIMING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...JR LONG TERM...JR/MAKOWSKI AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
326 AM CDT MON JUL 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 325 AM CDT MON JUL 8 2013 THE MAIN CONCERN IN THE SHORT TERM WILL BE THE CHANCE OF THUNDERSTORMS...SOME POSSIBLY SEVERE. EARLY MORNING RADAR MOSAIC SHOWS THUNDERSTORMS MOVING ACROSS NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA. THE HRRR CAPTURES THIS ACTIVITY AND MOVES IT INTO THE NORTH CENTRAL PART OF THE STATE LATER THIS MORNING. MUCAPE FROM THE SPC MESOSCALE ANALYSIS PAGE SHOWS VALUES NEAR 1000 J/KG THIS MORNING ACROSS NORTHWEST / NORTH CENTRAL NORTH DAKOTA...SO AN ISOLATED STRONG STORM IS POSSIBLE. ATTENTION THIS AFTERNOON SHIFTS TO A BOUNDARY THAT IS EXPECTED TO BECOME ESTABLISHED FROM SOUTHWEST NORTH DAKOTA INTO THE NORTH CENTRAL PART OF THE STATE. THE LATEST RAP SHOWS CONVECTION DEVELOPING ALONG THE BOUNDARY BY EARLY AFTERNOON. THERE WILL BE GOOD INSTABILITY IN PLACE WITH MLCAPE VALUES OF 1500-2500 J/KG...AND DEEP LAYER SHEAR OF 40 KTS SHOULD SUPPORT SUPERCELLS. THE MAIN THREATS ARE EXPECTED TO BE LARGE HAIL AND DAMAGING WINDS...THOUGH AN ISOLATED TORNADO IS ALSO POSSIBLE. LATER TONIGHT...A STRONG H5 WAVE IS EXPECTED TO MOVE ACROSS MONTANA INTO NORTH DAKOTA. THIS WILL HELP INCREASE THUNDERSTORM COVERAGE...WITH THE POTENTIAL DEVELOPMENT OF AN EASTWARD PROPAGATING MCS. THIS WILL GRADUALLY SHIFT THE PRIMARY THUNDERSTORM THREATS TO DAMAGING WINDS AND HEAVY RAIN LATER TONIGHT. SEE THE HYDRO SECTION BELOW WHICH DISCUSSES THE HEAVY RAIN POTENTIAL. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 AM CDT MON JUL 8 2013 THE CHALLENGE IN THE EXTENDED WILL BE ENDING THE PRECIPITATION CHANCES TUESDAY AS THE SHORTWAVE EXITS THE REGION. BELIEVE RESIDUAL SHOWERS AND THUNDERSTORMS WILL BE IN THE NORTH AND EAST TUESDAY MORNING...WITH ONLY A SLIGHT CHANCE SOUTH. THE PRECIPITATION WILL LIKELY BE EXITING THE REGION BY EARLY AFTERNOON...SO BY EVENING TUESDAY IT SHOULD BE DRY ACROSS THE REGION. THIS WILL BE FOLLOWED BY A RELATIVELY QUIET PERIOD WEDNESDAY AND THURSDAY AS AN H500 RIDGE BUILDS INTO THE REGION. HOWEVER...MUCH WARMER TEMPERATURES ASSOCIATED WITH THE RIDGE WILL ALSO ARRIVE IN THE WEST ON THURSDAY AND CONTINUE INTO FRIDAY. BOTH GFS AND ECMWF MODELS SUPPORT THIS SCENARIO. EXPECT HIGH TEMPERATURES WEDNESDAY INTO THE LOW TO MIDDLE 90S WEST...UPPER 80S TO AROUND 90 CENTRAL. AS THE RIDGE MOVES EAST ON FRIDAY INTO THE WEEKEND...WILL BE PICKING UP MORE CHANCES FOR THUNDERSTORMS AS SHORTWAVE ENERGY WILL AGAIN BE MOVING THROUGH THE NORTHERN PLAINS. THAT BEING 5 TO 7 DAYS OUT...AND WITH MODELS DIFFERING IN THE FLOW ALOFT...JUST MENTIONED SLIGHT CHANCE FOR THUNDERSTORMS FRIDAY INTO WEEKEND. GFS HAS BUILDING HEIGHTS FOR THIS PERIOD ALOFT WHILE THE EUROPEAN IS MORE ACTIVE WITH SHORTWAVE ENERGY MOVING THROUGH....ALTHOUGH BOTH MODELS WOULD SUPPORT SOME THUNDERSTORMS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 325 AM CDT MON JUL 8 2013 THE MAIN CONCERN FOR THE 06Z TAFS WILL BE THE CHANCE OF THUNDERSTORMS. EARLY MORNING RADARS SHOW THUNDERSTORMS MOVING ACROSS EASTERN MONTANA TOWARDS WESTERN NORTH DAKOTA. CONFIDENCE IN ANY OF THIS INITIAL ACTIVITY REACHING A TERMINAL LOCATION IS NOT HIGH...AND WILL ONLY CARRY VCTS AT KISN EARLY THIS MORNING. THUNDERSTORM CHANCES INCREASE THIS AFTERNOON AND TONIGHT AT ALL TERMINAL LOCATIONS. WILL START WITH VCTS / VCSH AT ALL SPOTS THIS AFTERNOON...AND TREND TOWARDS A PROB30 THIS EVENING FOR ALL BUT KBIS AND KJMS. && .HYDROLOGY... ISSUED AT 325 AM CDT MON JUL 8 2013 HEAVY RAIN IS POSSIBLE WITH MULTIPLE ROUNDS OF THUNDERSTORMS TODAY INTO TONIGHT. PRECIPITABLE WATER VALUES AROUND 1.5 INCHES ARE EXPECTED TONIGHT ACROSS MUCH OF THE FORECAST AREA. THE HEAVIEST RAIN POTENTIAL APPEARS TO BE ALONG AND NORTH OF HIGHWAY 200...WHERE AN EASTWARD PROPAGATING MCS IS POSSIBLE. 1 HOUR FLASH FLOOD GUIDANCE VALUES ARE AT LEAST 1.5 INCHES...AND 3 HOUR VALUES ARE GENERALLY IN THE 1.5 - 3.0 INCH RANGE. DECIDED TO HOLD OFF ON ANY FLASH FLOOD WATCHES FOR NOW DUE TO THE RELATIVELY HIGH FLASH FLOOD GUIDANCE VALUES AND EXPECTED PROGRESSIVE STORM MOTIONS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CK LONG TERM...WAA AVIATION...CK HYDROLOGY...CK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
851 PM EDT TUE JUL 9 2013 .SYNOPSIS... WITH A MOIST AND UNSTABLE AIR MASS IN PLACE...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THROUGH WEDNESDAY. A COLD FRONT WILL CROSS THE REGION WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE REST OF THE WEEK AND INTO THE WEEKEND...PROVIDING DRIER AND COOLER CONDITIONS. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS THE REGION. HEAVY RAIN REMAINS A SUBSTANTIAL THREAT. AND THERE IS STILL THE POSSIBILITY OF A FEW STRONGER CELLS. BUT THEN AFTER CURRENT STORMS MOVE OFF TO THE EAST IT SEEMS THAT THERE MAY BE A BREAK IN ACTIVITY. STILL PLENTY OF MOISTURE IN PLACE AND THERE COULD STILL BE FURTHER DEVELOPMENT OVERNIGHT. BUT RECENT HRRR AND RAP RUNS HAVE BACKED OFF ADDITIONAL STORMS. SO JUST KEPT A LOW CHANCE BEHIND CURRENT ACTIVITY. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... ACTIVE WEATHER WILL CONTINUE ON WEDNESDAY...WITH ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. THE MAIN DRIVER FOR THE CHANGING WEATHER INTO WEDNESDAY NIGHT WILL BE A COLD FRONT...MOVING SOUTHEAST INTO THE OHIO VALLEY...WITH HIGH PRESSURE BUILDING IN BEHIND. THE EXPECTED ONGOING CONVECTION ON TUESDAY NIGHT WILL CREATE AN UNCERTAIN SCENARIO FOR WEDNESDAY. 12Z RUNS OF THE WRF-ARW AND WRF-NMM...COMBINED WITH NUMEROUS RUNS OF THE HRRR...DO SHOW ADDITIONAL CONVECTION PROPAGATING SOUTHWARD AND IMPACTING THE CWA OVERNIGHT INTO EARLY WEDNESDAY MORNING. THE LARGER SCALE MODELS ALSO SHOW THAT WHILE DEEPER MOISTURE WILL ALREADY BE EXITING THE CWA BY 18Z WEDNESDAY...LOW LEVEL MOISTURE WILL STILL PERSIST...LIKELY RESULTING IN CLOUD COVER. WHAT SEEMS TO BE THE MOST LIKELY SCENARIO WOULD BE FOR A PARTIAL LULL IN PRECIPITATION DURING THE DIURNAL MINIMUM PERIOD...FOLLOWED BY ADDITIONAL DEVELOPMENT IN A MODIFIED AIR MASS DURING THE AFTERNOON AHEAD OF THE FRONT (TAKING ADVANTAGE OF WHATEVER HEATING IS ABLE TO DEVELOP). NAM/GFS INSTABILITY FORECASTS ARE RATHER HIGH ON WEDNESDAY AFTERNOON (3000-4000 J/KG)...DUE AS MUCH TO THE FORECAST DEWPOINTS (MID TO UPPER 70S...PERHAPS A BIT TOO HIGH) AS WELL AS THE EXPECTED SURFACE HEATING. HOWEVER...ULTIMATELY...IMPACTS FROM OVERNIGHT AND EARLY MORNING CONVECTION COULD SIGNIFICANTLY DISRUPT THESE FORECASTS (PARTICULARLY WITH REGARD TO THE TEMPERATURE PROFILES)...WHICH LEAVES SOME UNCERTAINTY IN THE SEVERE FORECAST TOMORROW. DUE TO THE RESPECTABLE FORCING COMING ALONG WITH THE COLD FRONT...THE INCREASING SHEAR (ESPECIALLY AS OPPOSED TO THE RELATIVELY WEAK SHEAR TUESDAY)...AND THE POTENTIAL FOR MODERATE TO HIGH INSTABILITY...WEDNESDAY CERTAINLY NEEDS TO BE MONITORED FOR A SEVERE POTENTIAL. CONFIDENCE IS SIMPLY NOT HIGH IN A SPECIFIC SCENARIO. THOUGH MOST OF THE DEEP MOISTURE WILL BE EAST OF THE AREA BY WEDNESDAY AFTERNOON...PWATS SHOW A SLIGHT INCREASE JUST AHEAD OF THE FRONT. AS THE MAGNITUDE AND COVERAGE FORECASTS OF CONVECTION REMAIN UNCERTAIN...THUS THE THREAT FOR ADDITIONAL HEAVY RAIN REMAINS UNCERTAIN AS WELL. IF THE TIMING OF THE FRONTAL PASSAGE HAS CHANGED AT ALL SINCE PREVIOUS FORECASTS...IT APPEARS SLIGHTLY FASTER. THIS NECESSITATED A LOWERING IN MIN TEMPS (PRIMARILY IN THE NW CWA). ALSO...THE HIGHER POPS WERE ENDED FROM NW TO SE SLIGHTLY QUICKER. && .LONG TERM /THURSDAY THROUGH TUESDAY/... SHOWERS WILL COME TO AN END BY THE MIDDLE OF THE DAY ON THURSDAY AS A FRONTAL BOUNDARY MOVES OUT OF THE AREA. WITH COOLER AIR FILTERING INTO THE AREA NOT EXPECTING TEMPERATURES TO RISE MUCH ON THURSDAY WITH HIGH TEMPERATURES IN THE MIDDLE 70S TO THE LOW 80S. HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH THE WEEKEND WITH DRY CONDITIONS EXPECTED AND A GRADUAL WARMING TREND. ON MONDAY AND TUESDAY THE SE PORTIONS OF THE FA WILL BE ON THE EDGE OF SYSTEM SE OF THE FA. THERE ARE INDICATIONS THAT EXTREME SE PORTIONS OF THE FA MAY HAVE A FEW SHOWERS IMPACT THE AREA HOWEVER THE CHANCE OF THIS OCCURRING IS PRETTY LOW. DUE TO THIS HAVE DECIDED TO LEAVE PRECIPITATION OUT OF THE FORECAST AT THIS TIME. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THUNDERSTORMS MAY STILL AFFECT THE CENTRAL OHIO TERMINALS EARLY IN THE FORECAST PERIOD. AFTER THESE MOVE OFF THERE COULD STILL BE ADDITIONAL SHOWERS OR THUNDERSTORMS DEVELOPING OVERNIGHT. PROBABILITY IS NOT THAT HIGH AT THIS POINT BUT DID INCLUDE A PERIOD OF VCSH. THEREAFTER HAVE HELD OFF ON ANY ADDITIONAL PRECIPITATION MENTION UNTIL LATE IN THE TAF PERIOD WHEN A LINE OF STORMS IS EXPECTED TO DEVELOP AHEAD OF AN APPROACHING COLD FRONT. OUTSIDE OF ANY CONVECTION CONDITIONS SHOULD REMAIN VFR. OUTLOOK...GOOD CHANCE OF THUNDERSTORMS WEDNESDAY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH THROUGH WEDNESDAY EVENING FOR OHZ026-034-035- 043>046-051>056-062>065-073-074. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM... SHORT TERM...HATZOS LONG TERM...NOVAK AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
920 PM EDT TUE JUL 9 2013 .SYNOPSIS... A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA WEDNESDAY NIGHT AND THURSDAY. A MUCH LESS HUMID AIRMASS WILL ARRIVE LATER THURSDAY AND REMAIN INTO THE WEEKEND PROVIDING WELCOME RELIEF FROM THE RECENT ABNORMALLY HUMID AND WET CONDITIONS. A RETURN TO MORE TYPICAL SUMMERTIME CONDITIONS IS EXPECTED BY EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... RADAR IS RATHER QUIET WITH JUST A COUPLE OF SMALL SHOWERS OVER WESTERN AND SOUTHWESTERN SECTIONS. A MORE EXTENSIVE LINE OF SHOWERS AND THUNDERSTORMS IS MOVING STEADILY EAST FROM OHIO AND FAR SWRN PA. I TIMED THEM INTO MY WESTERN ZONES AFTER 03Z...BUT CONFIDENCE IS LOW WHETHER THEY CAN MAINTAIN AFTER WE LOSE HEATING. MODELS SHOW A TYPICAL INCREASE IN STABILITY AFTER SUNDOWN...AND THE HRRR AND ARW BOTH KILL THE SHOWERS AS THEY ENTER CENTRAL PA. THE 4KM NAM HOWEVER MAINTAINS THEM FOR A TIME AS THEY MOVE OUR WAY. FOR THE NEXT FEW HOURS I SHOW INCREASING CHANCES FOR RAIN FROM WEST TO EAST...THEN AFTER MIDNIGHT IT`S A MORE BLAND FORECAST AS WE DEAL WITH THE POTENTIAL FOR ADDITIONAL SHOWERS CONTINUING TO BLEED ACROSS FROM THE OHIO VALLEY. IT WILL BE ANOTHER VERY MUGGY NIGHT WITH LOWS FROM THE MID TO UPPER 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... HIGH PWAT AIR IN PLACE WILL BRING WIDESPREAD SHOWERS AND SCT TSTMS THROUGH WED AS DYNAMICS AND LIFT INCREASE AHEAD OF AN APPROACHING COLD FRONT. REGION IS PROGGED FOR SPC DAY 2 SLIGHT RISK...WITH DIURNAL HEATING AND BEING ON THE EDGE OF MARGINALLY STRONG FLOW. AS MID-LEVEL LAPSE RATES STEEPEN...TSTMS SHOULD INCREASE IN COVERAGE AND STRENGTH AS THEY EVOLVE INTO MULTI-CELLULAR CLUSTERS. THEY WILL ALSO BE EFFICIENT RAIN PRODUCERS...SO ANY LINGERING CELLS COULD PRODUCE LOCALIZED PROBLEMS WITH RUNOFF - AS GROUND REMAINS QUITE WET IN MANY LOCATIONS. FRONTAL BOUNDARY HANGS BACK TO THE NW DURING THE DAY WED...BUT SHOULD SLOWLY CROSS CWA WED NIGHT INTO THU. THIS WILL BRING CONTINUATION OF SCT SHOWERS/TSTMS...ESP ACROSS THE SOUTHEAST. DEWPOINTS WILL EVENTUALLY LOWER...BRINGING SOME RELIEF FROM THE PERSISTENT MUGGY WEATHER...BUT THIS WILL TAKE SOME TIME - LIKELY INTO THU - BEFORE AIRMASS DRIES OUT. && .LONG TERM /THURSDAY THROUGH TUESDAY/... ON DAY3/THURSDAY...THE ERN U.S UPPER TROUGH WILL UNDERGO FURTHER AMPLIFICATION AS IT SHIFTS SEWD FROM THE GREAT LAKES INTO THE NORTHEAST STATES BY FRIDAY MORNING. THE MODELS SHOW GOOD LARGE SCALE AGREEMENT CONCERNING THE TROUGH PROGRESSION...THUS A GENERAL MODEL COMPROMISE IS PREFERRED WITH ABOVE AVG CONFIDENCE CONSIDERING ITS INCREASINGLY AMPLIFIED NATURE. AT THE SFC...THE ASSOCIATED COLD FRONT SHOULD PRESS SEWD THROUGH THE LAUREL HIGHLANDS/S-CNTRL MTNS AND LWR SUSQ VLY DURING THE EARLY-MID AFTN. WHILE THE BEST MSTR /SFC DEWPOINTS IN THE UPPER 60S TO LOW 70S/ AND 1"+ PWATS WILL RESIDE ALONG/EAST OF THE I-95 CORRIDOR...IT APPEARS THERE WILL BE ENOUGH INSTABILITY IN THE PRE-FRONTAL WARM SECTOR TO PRODUCE SCATTERED MULTI-CELL STORMS WITH AN ISOLD SVR THREAT ACRS THE FAR SRN TIER PRIOR TO A MID-TO-LATE DAY FROPA. THE DAY 3 SPC SEE TEXT/5% SVR PROBS INCLUDE THE SRN 1/3 OF THE CWA FROM SOMERSET TO SCHUYLKILL COUNTY...BUT BASED ON THE FCST POSITION OF THE FRONT AND LLVL MSTR GRADIENT/AXIS...THE GREATEST RISK FOR SVR STORMS IS LKLY ALONG THE FAR SRN TIER ZONES OR JUST OUTSIDE OF MY CWA. AN AREA OF SFC HIGH PRESSURE WILL MIGRATE EWD ACRS THE GREAT LAKES REGION AND EXPAND OVER THE NORTHEAST STATES...AS THE UPPER LEVEL PATTERN TRANSITIONS FROM AN ANOMALOUSLY AMPLIFIED PATTERN TO NEARLY CONUS-WIDE RIDGING BY EARLY NEXT WEEK. THE NLY FLOW AROUND THE SFC HIGH WILL ADVECT A MUCH DRIER/BELOW NORMAL PWAT AIRMASS INTO PA FROM THURS NGT THRU SATURDAY AND PROVIDE A BRIEF RESPITE FROM THE RECENT ABNORMALLY MOIST/WET TROPICAL-LIKE ENVIRONMENT. PCPN SHOULD REMAIN FOCUSED SOUTH OF THE REGION AS THE DAY 3 SFC BOUNDARY BECOMES QUASI-STATIONARY OVER THE SRN MID-ATLC AND SERN STATES. AS FOR TEMPERATURES...EXPECT A FEW RELATIVELY COOL NIGHTS LATER THIS WEEK WITH LOWS IN THE 55-65F RANGE. THE PATTERN BEGINS TO REVERT BACK TO A TYPICAL SUMMERTIME REGIME WITH A BERMUDA HIGH SETTING-UP OFF THE EAST COAST. THIS WILL ALLOW FOR WARMER TEMPERATURES AND INCREASING HUMIDITY INTO EARLY NEXT WEEK...ALONG WITH A LOW CHC FOR DIURNAL CONVECTION. THE FLOW AROUND THE BERMUDA HIGH SHOULD STEER TS CHANTAL ON A WWD TRACK FROM THE CARIBBEAN/HISPANIOLA TO THE NORTHWEST BAHAMAS THUR-SAT...AND THEN INTO N-CENTRAL FLORIDA FROM SUN-TUE. CONFIDENCE IN THE FORECAST OF THIS FEATURE IS BELOW AVERAGE AS MANY TROPICAL CYCLONES HAVE DISSIPATED WHILE TRYING TO CROSS THE MOUNTAINOUS ISLAND. PLEASE REFER TO THE NATIONAL HURRICANE CENTER (NHC) FOR THE LATEST TROPICAL INFORMATION CONCERNING TS CHANTAL. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... MVFR CIGS HAVE SET UP OVER THE WESTERN TAF SITES. EXPECT THESE CLOUDS TO CONTINUE. THE NEXT AVIATION CONCERN WILL BE THE LINE OF CONVECTION CURRENTLY MOVING INTO WESTERN PA. WHILE IT WILL SLOWLY WEAKEN AS THE EVENING PROGRESSES...IT SHOULD STILL BE STRONG ENOUGH TO AFFECT JST AND AOO. EXPECT IT TO BE IN THE VICINITY OF JST BY 02Z AND AOO BY 03Z. THESE STORMS ARE ISOLATED SO THERE ISN`T ANY STORMS BACKFILLING. THE ADDED MOISTURE SHOULD FURTHER INCREASE THE PROBABILITIES FOR MVFR/IFR CIGS AND VSBYS OVERNIGHT...THROUGH 12Z WITH THE INCREASING LOW LEVEL FLOW AND REINFORCING LOW CLOUDS COULD BRING LIGHT FOG ACROSS CENTRAL PA OVERNIGHT. HIGH PWAT AIR IN PLACE WILL BRING RESTRICTIONS IN WIDESPREAD SHOWERS AND SCT TSTMS WED AS DYNAMICS AND LIFT INCREASE AHEAD OF AN APPROACHING COLD FRONT. REGION IS PROGGED FOR SPC DAY 2 SLIGHT RISK...WITH DIURNAL HEATING AND BEING ON THE EDGE OF MARGINALLY STRONG FLOW. AS MID- LEVEL LAPSE RATES STEEPEN...TSTMS SHOULD INCREASE IN COVERAGE AND STRENGTH AS THEY EVOLVE INTO MULTI CELLULAR CLUSTERS. FRONTAL BOUNDARY HANGS BACK TO THE NW DURING THE DAY WED...BUT SHOULD SLOWLY CROSS CWA WED NIGHT INTO THU. THIS WILL BRING CONTINUATION OF SCT SHOWERS/TSTMS...ESP ACROSS THE SOUTHEAST. OUTLOOK... WED...AM LOW CIGS. SCT/LIKELY TSRA BRINGING RESTRICTIONS. THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSSIBLE. FRI-SAT...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...RXR LONG TERM...STEINBUGL AVIATION...CERU/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
751 PM EDT TUE JUL 9 2013 .SYNOPSIS... A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA WEDNESDAY NIGHT AND THURSDAY. A MUCH LESS HUMID AIRMASS WILL ARRIVE LATER THURSDAY AND REMAIN INTO THE WEEKEND PROVIDING WELCOME RELIEF FROM THE RECENT ABNORMALLY HUMID AND WET CONDITIONS. A RETURN TO MORE TYPICAL SUMMERTIME CONDITIONS IS EXPECTED BY EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... RADAR IS RATHER QUIET WITH JUST A COUPLE OF SMALL SHOWERS OVER WESTERN AND SOUTHWESTERN SECTIONS. A MORE EXTENSIVE LINE OF SHOWERS AND THUNDERSTORMS IS MOVING STEADILY EAST FROM OHIO AND FAR SWRN PA. I TIMED THEM INTO MY WESTERN ZONES AFTER 03Z...BUT CONFIDENCE IS LOW WHETHER THEY CAN MAINTAIN AFTER WE LOSE HEATING. MODELS SHOW A TYPICAL INCREASE IN STABILITY AFTER SUNDOWN...AND THE HRRR AND ARW BOTH KILL THE SHOWERS AS THEY ENTER CENTRAL PA. THE 4KM NAM HOWEVER MAINTAINS THEM FOR A TIME AS THEY MOVE OUR WAY. FOR THE NEXT FEW HOURS I SHOW INCREASING CHANCES FOR RAIN FROM WEST TO EAST...THEN AFTER MIDNIGHT IT`S A MORE BLAND FORECAST AS WE DEAL WITH THE POTENTIAL FOR ADDITIONAL SHOWERS CONTINUING TO BLEED ACROSS FROM THE OHIO VALLEY. IT WILL BE ANOTHER VERY MUGGY NIGHT WITH LOWS FROM THE MID TO UPPER 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... HIGH PWAT AIR IN PLACE WILL BRING WIDESPREAD SHOWERS AND SCT TSTMS THROUGH WED AS DYNAMICS AND LIFT INCREASE AHEAD OF AN APPROACHING COLD FRONT. REGION IS PROGGED FOR SPC DAY 2 SLIGHT RISK...WITH DIURNAL HEATING AND BEING ON THE EDGE OF MARGINALLY STRONG FLOW. AS MID-LEVEL LAPSE RATES STEEPEN...TSTMS SHOULD INCREASE IN COVERAGE AND STRENGTH AS THEY EVOLVE INTO MULTI-CELLULAR CLUSTERS. THEY WILL ALSO BE EFFICIENT RAIN PRODUCERS...SO ANY LINGERING CELLS COULD PRODUCE LOCALIZED PROBLEMS WITH RUNOFF - AS GROUND REMAINS QUITE WET IN MANY LOCATIONS. FRONTAL BOUNDARY HANGS BACK TO THE NW DURING THE DAY WED...BUT SHOULD SLOWLY CROSS CWA WED NIGHT INTO THU. THIS WILL BRING CONTINUATION OF SCT SHOWERS/TSTMS...ESP ACROSS THE SOUTHEAST. DEWPOINTS WILL EVENTUALLY LOWER...BRINGING SOME RELIEF FROM THE PERSISTENT MUGGY WEATHER...BUT THIS WILL TAKE SOME TIME - LIKELY INTO THU - BEFORE AIRMASS DRIES OUT. && .LONG TERM /THURSDAY THROUGH TUESDAY/... ON DAY3/THURSDAY...THE ERN U.S UPPER TROUGH WILL UNDERGO FURTHER AMPLIFICATION AS IT SHIFTS SEWD FROM THE GREAT LAKES INTO THE NORTHEAST STATES BY FRIDAY MORNING. THE MODELS SHOW GOOD LARGE SCALE AGREEMENT CONCERNING THE TROUGH PROGRESSION...THUS A GENERAL MODEL COMPROMISE IS PREFERRED WITH ABOVE AVG CONFIDENCE CONSIDERING ITS INCREASINGLY AMPLIFIED NATURE. AT THE SFC...THE ASSOCIATED COLD FRONT SHOULD PRESS SEWD THROUGH THE LAUREL HIGHLANDS/S-CNTRL MTNS AND LWR SUSQ VLY DURING THE EARLY-MID AFTN. WHILE THE BEST MSTR /SFC DEWPOINTS IN THE UPPER 60S TO LOW 70S/ AND 1"+ PWATS WILL RESIDE ALONG/EAST OF THE I-95 CORRIDOR...IT APPEARS THERE WILL BE ENOUGH INSTABILITY IN THE PRE-FRONTAL WARM SECTOR TO PRODUCE SCATTERED MULTI-CELL STORMS WITH AN ISOLD SVR THREAT ACRS THE FAR SRN TIER PRIOR TO A MID-TO-LATE DAY FROPA. THE DAY 3 SPC SEE TEXT/5% SVR PROBS INCLUDE THE SRN 1/3 OF THE CWA FROM SOMERSET TO SCHUYLKILL COUNTY...BUT BASED ON THE FCST POSITION OF THE FRONT AND LLVL MSTR GRADIENT/AXIS...THE GREATEST RISK FOR SVR STORMS IS LKLY ALONG THE FAR SRN TIER ZONES OR JUST OUTSIDE OF MY CWA. AN AREA OF SFC HIGH PRESSURE WILL MIGRATE EWD ACRS THE GREAT LAKES REGION AND EXPAND OVER THE NORTHEAST STATES...AS THE UPPER LEVEL PATTERN TRANSITIONS FROM AN ANOMALOUSLY AMPLIFIED PATTERN TO NEARLY CONUS-WIDE RIDGING BY EARLY NEXT WEEK. THE NLY FLOW AROUND THE SFC HIGH WILL ADVECT A MUCH DRIER/BELOW NORMAL PWAT AIRMASS INTO PA FROM THURS NGT THRU SATURDAY AND PROVIDE A BRIEF RESPITE FROM THE RECENT ABNORMALLY MOIST/WET TROPICAL-LIKE ENVIRONMENT. PCPN SHOULD REMAIN FOCUSED SOUTH OF THE REGION AS THE DAY 3 SFC BOUNDARY BECOMES QUASI-STATIONARY OVER THE SRN MID-ATLC AND SERN STATES. AS FOR TEMPERATURES...EXPECT A FEW RELATIVELY COOL NIGHTS LATER THIS WEEK WITH LOWS IN THE 55-65F RANGE. THE PATTERN BEGINS TO REVERT BACK TO A TYPICAL SUMMERTIME REGIME WITH A BERMUDA HIGH SETTING-UP OFF THE EAST COAST. THIS WILL ALLOW FOR WARMER TEMPERATURES AND INCREASING HUMIDITY INTO EARLY NEXT WEEK...ALONG WITH A LOW CHC FOR DIURNAL CONVECTION. THE FLOW AROUND THE BERMUDA HIGH SHOULD STEER TS CHANTAL ON A WWD TRACK FROM THE CARIBBEAN/HISPANIOLA TO THE NORTHWEST BAHAMAS THUR-SAT...AND THEN INTO N-CENTRAL FLORIDA FROM SUN-TUE. CONFIDENCE IN THE FORECAST OF THIS FEATURE IS BELOW AVERAGE AS MANY TROPICAL CYCLONES HAVE DISSIPATED WHILE TRYING TO CROSS THE MOUNTAINOUS ISLAND. PLEASE REFER TO THE NATIONAL HURRICANE CENTER (NHC) FOR THE LATEST TROPICAL INFORMATION CONCERNING TS CHANTAL. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... SHOWERS AND THUNDERSTORMS HAVE EXITED THE REGION AND THE FIRST HALF OF THE EVENING SHOULD BE FAIRLY QUIET. MVFR CIGS HAVE SET UP OVER THE WESTERN TAF SITES. EXPECT THESE CLOUDS TO CONTINUE. THE NEXT AVIATION CONCERN WILL BE THE LINE OF CONVECTION CURRENTLY MOVING THROUGH SOUTH WESTERN MICHIGAN AND CENTRAL OHIO. THOUGH IT WILL BE TAPERED OVERNIGHT...THERE COULD BE ENOUGH DYNAMICS TO ALLOW IT TO AFFECT CENTRAL PA TOMORROW MORNING. THE INCREASING LOW LEVEL FLOW AND REINFORCING LOW CLOUDS COULD BRING LIGHT FOG ACROSS CENTRAL PA OVERNIGHT. HIGH PWAT AIR IN PLACE WILL BRING RESTRICTIONS IN WIDESPREAD SHOWERS AND SCT TSTMS WED AS DYNAMICS AND LIFT INCREASE AHEAD OF AN APPROACHING COLD FRONT. REGION IS PROGGED FOR SPC DAY 2 SLIGHT RISK...WITH DIURNAL HEATING AND BEING ON THE EDGE OF MARGINALLY STRONG FLOW. AS MID- LEVEL LAPSE RATES STEEPEN...TSTMS SHOULD INCREASE IN COVERAGE AND STRENGTH AS THEY EVOLVE INTO MULTI CELLULAR CLUSTERS. FRONTAL BOUNDARY HANGS BACK TO THE NW DURING THE DAY WED...BUT SHOULD SLOWLY CROSS CWA WED NIGHT INTO THU. THIS WILL BRING CONTINUATION OF SCT SHOWERS/TSTMS...ESP ACROSS THE SOUTHEAST. OUTLOOK... WED...AM LOW CIGS. SCT/LIKELY TSRA BRINGING RESTRICTIONS. THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSSIBLE. FRI-SAT...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...RXR LONG TERM...STEINBUGL AVIATION...CERU/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1155 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER WESTERN PA. REGIONAL RADAR MOSAIC SHOWS SCATTERED CONVECTION PINWHEELING AROUND THIS FEATURE FROM OHIO TO THE MID ATL COAST. HIGH PRESSURE WILL REMAIN IN CONTROL FOR THE MOST PART TODAY IN THE WAKE OF THE UPPER TROF/LOW. WITH THE UPPER SYSTEM PRETTY MUCH OVERHEAD TO START THE DAY...LARGE SCALE ASCENT AND SOME MODEST INSTABILITY WILL HELP TRIGGER SCATTERED SHOWERS/TSTMS. GRAVITY WAVE SLIDING SE HAS HELPED KICK OFF SCT TSTMS ALONG A NORTH- SOUTH LINE SPLITTING CWA...AND THIS CONVECTION WILL DRIFT EASTWARD THROUGH EARLY AFTERNOON. TIMING OF THE UPPER TROF/LOW SUGGESTS THAT MOST CONVECTION WILL LAST INTO MID AFTERNOON...WITH EXPECTED RISING HEIGHTS AND MID LEVEL WARMING HELPING TO PUT A LID ON THINGS LATER IN THE DAY. THE CLOUDS AND SCATTERED SHOWERS WILL HELP LIMIT TODAY`S MAX TEMPS WITH HIGHS RANGING FROM THE MID 70S TO MID 80S FROM NW TO SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... IN THE WAKE OF OUR DEPARTING LOW...WE WILL BEGIN TO SEE THE UPPER FLOW BECOMING MORE WESTERLY WITH THE LOCAL AREA BEING CLOSE TO THE SOUTHERN EDGE OF THIS WESTERLY FLOW. FOR THE OVERNIGHT THERE IS SOME MEASURE OF AGREEMENT THAT CONVECTION CURRENTLY OVER THE WESTERN GR LAKES WILL SPILL DOWN AND COME THROUGH THE AREA LATER AT NIGHT AS AN MCS. THE SREF AND GEFS BOTH LATCH ONTO THIS...WITH SLIGHT PLACEMENT DIFFERENCES. I USED THIS TO BRING HIGHER POPS INTO THE AREA AFTER MIDNIGHT AND INTO TUESDAY MORNING. THE MODELS DIMINISH THE INSTABILITY AFTER SUNSET SO AM NOT TOO CONCERNED ABOUT LATE NIGHT SEVERE WEATHER...BUT SOME NOCTURNAL ELEVATED THUNDER LOOKS LIKE A REASONABLE POSSIBILITY. ONCE THE CONVECTION PASSES...PROBABLY BY MID TO LATE MORNING TUESDAY...THE AFTERNOON SHOULD BE RELATIVELY QUIET WITH TEMPERATURES REBOUNDING WELL INTO THE 80S REGION-WIDE...WITH THE HUMIDITY HANGING IN TOUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE PERIOD OF NEARLY ZONAL FLOW ALOFT WILL BE RELATIVELY SHORT-LIVED AS THE ROCKIES RIDGE IS EXPECTED TO EXPERIENCE A RESURGENCE...RESULTING IN THE DOWNSTREAM TROUGH DIGGING OVER THE EASTERN US. YESTERDAY`S MODEL RUNS SHOWED THE DEVELOPMENT OF A PATTERN THAT LOOKED MUCH LIKE WHAT WE WERE RECENTLY SADDLED WITH FOR OVER A WEEK WITH A DEEP LOW OVER THE TN/OH VALLEY AND A STRONG BERMUDA RIDGE NOSING INTO THE EASTERN SEABOARD KEEPING A DEEP SOUTHERLY FLOW OF TROPICAL AIR LOCKED IN OVER THE EASTERN US. THE LATEST RUNS DO CREATE AN UPPER LOW/TROUGH BUT TONIGHT THE GUIDANCE IS FASTER AND DOESN`T STALL THE LOW. INDICATIONS ARE THAT WHATEVER FORMS BETWEEN THE BERMUDA RIDGE AND THE RIDGE IN THE ROCKIES WILL BE RELATIVELY WEAK AND EITHER SETTLE SOUTH INTO THE GULF OR BECOME LOST AS A GENERAL WEAKNESS BETWEEN WHAT THE GEFS SHOWS AS A HUGE AREA OF ANOMALOUSLY HIGH HEIGHTS ASSOCIATED WITH THE SUBTROPICAL RIDGE FROM THE CENTRAL ATLANTIC ALL THE WAY WEST TO THE ROCKY MOUNTAINS BY NEXT WEEKEND. THIS IS INTERESTING FOR THE EVENTUAL DEVELOPMENTS ASSOCIATED WITH CHANTAL. WHILE THE STORM IS EXPECTED TO ENCOUNTER LAND AS WELL AS INCREASING WIND SHEAR...AND THERE IS SOME QUESTION THAT IT WILL EVEN SURVIVE AS IT TREKS WESTWARD TOWARD THE CARIBBEAN OR BAHAMAS...IF IT DOES SURVIVE...THE EVENTUAL PATH SEEMS PAVED FOR A TRACK INTO THE SERN US OR THE EAST COAST AS THE SUBTROPICAL RIDGE LOOKS ABNORMALLY MIGHTY FOR THIS TIME OF YEAR. STILL THE BETTER PART OF A WEEK BEFORE THAT HAPPENS. IN THE MEAN TIME A DECENT LOOKING COLD FRONT IS EXPECTED TO PASS THROUGH THE REGION ALONG ABOUT THURSDAY ASSOCIATED WITH THE UPPER TROUGH THAT IS EXPECTED TO DEVELOP OVER THE EASTERN US. IT SHOULD USHER IN SOME DRIER AIR FOR THE WEEK`S END THAT COULD LAST A DAY OR TWO BEFORE THE RIDGE REASSERTS ITSELF LOCALLY. OVERALL IT LOOKS LIKE ANOTHER VERY SUMMERY WEEK...PRETTY TYPICAL FOR EARLY JULY. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... EXPECT WIDESPREAD VFR CONDS THIS AFTERNOON. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING A CHC OF BRIEF SHRA/TSRA AND ACCOMPANYING LOCAL RESTRICTIONS THROUGH AFTERNOON HOURS. WE/LL SEE A MINIMUM OF CONVECTION THIS EVE. BUT LATER TONIGHT INTO EARLY TUES...MODELS SHOWING MCS SYSTEM DROPPING ACROSS CWA FROM GLAKES. WED COULD FEATURE SOME STRONG STORMS WITH PASSAGE OF A COLD FRONT...GIVEN STRONG DYNAMICS AND WARM ADVECTION. PERHAPS BETTER AVIATION WEATHER BY LATE IN THE WEEK. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
827 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER WESTERN PA. REGIONAL RADAR MOSAIC SHOWS SCATTERED CONVECTION PINWHEELING AROUND THIS FEATURE FROM OHIO TO THE MID ATL COAST. HIGH PRESSURE WILL REMAIN IN CONTROL FOR THE MOST PART TODAY IN THE WAKE OF THE UPPER TROF/LOW. WITH THE UPPER SYSTEM PRETTY MUCH OVERHEAD TO START THE DAY...LARGE SCALE ASCENT AND SOME MODEST INSTABILITY WILL HELP TRIGGER SOME SCATTERED SHOWERS. TIMING OF THE UPPER TROF/LOW SUGGESTS THAT MOST SHOWERS WILL BE FROM LATE MORNING THROUGH MID AFTERNOON...WITH EXPECTED RISING HEIGHTS AND MID LEVEL WARMING HELPING TO PUT A LID ON THINGS LATER IN THE DAY. THE CLOUDS AND SCATTERED SHOWERS WILL HELP LIMIT TODAY`S MAX TEMPS WITH HIGHS RANGING FROM THE MID 70S TO MID 80S FROM NW TO SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... IN THE WAKE OF OUR DEPARTING LOW...WE WILL BEGIN TO SEE THE UPPER FLOW BECOMING MORE WESTERLY WITH THE LOCAL AREA BEING CLOSE TO THE SOUTHERN EDGE OF THIS WESTERLY FLOW. FOR THE OVERNIGHT THERE IS SOME MEASURE OF AGREEMENT THAT CONVECTION CURRENTLY OVER THE WESTERN GR LAKES WILL SPILL DOWN AND COME THROUGH THE AREA LATER AT NIGHT AS AN MCS. THE SREF AND GEFS BOTH LATCH ONTO THIS...WITH SLIGHT PLACEMENT DIFFERENCES. I USED THIS TO BRING HIGHER POPS INTO THE AREA AFTER MIDNIGHT AND INTO TUESDAY MORNING. THE MODELS DIMINISH THE INSTABILITY AFTER SUNSET SO AM NOT TOO CONCERNED ABOUT LATE NIGHT SEVERE WEATHER...BUT SOME NOCTURNAL ELEVATED THUNDER LOOKS LIKE A REASONABLE POSSIBILITY. ONCE THE CONVECTION PASSES...PROBABLY BY MID TO LATE MORNING TUESDAY...THE AFTERNOON SHOULD BE RELATIVELY QUIET WITH TEMPERATURES REBOUNDING WELL INTO THE 80S REGION-WIDE...WITH THE HUMIDITY HANGING IN TOUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE PERIOD OF NEARLY ZONAL FLOW ALOFT WILL BE RELATIVELY SHORT-LIVED AS THE ROCKIES RIDGE IS EXPECTED TO EXPERIENCE A RESURGENCE...RESULTING IN THE DOWNSTREAM TROUGH DIGGING OVER THE EASTERN US. YESTERDAY`S MODEL RUNS SHOWED THE DEVELOPMENT OF A PATTERN THAT LOOKED MUCH LIKE WHAT WE WERE RECENTLY SADDLED WITH FOR OVER A WEEK WITH A DEEP LOW OVER THE TN/OH VALLEY AND A STRONG BERMUDA RIDGE NOSING INTO THE EASTERN SEABOARD KEEPING A DEEP SOUTHERLY FLOW OF TROPICAL AIR LOCKED IN OVER THE EASTERN US. THE LATEST RUNS DO CREATE AN UPPER LOW/TROUGH BUT TONIGHT THE GUIDANCE IS FASTER AND DOESN`T STALL THE LOW. INDICATIONS ARE THAT WHATEVER FORMS BETWEEN THE BERMUDA RIDGE AND THE RIDGE IN THE ROCKIES WILL BE RELATIVELY WEAK AND EITHER SETTLE SOUTH INTO THE GULF OR BECOME LOST AS A GENERAL WEAKNESS BETWEEN WHAT THE GEFS SHOWS AS A HUGE AREA OF ANOMALOUSLY HIGH HEIGHTS ASSOCIATED WITH THE SUBTROPICAL RIDGE FROM THE CENTRAL ATLANTIC ALL THE WAY WEST TO THE ROCKY MOUNTAINS BY NEXT WEEKEND. THIS IS INTERESTING FOR THE EVENTUAL DEVELOPMENTS ASSOCIATED WITH CHANTAL. WHILE THE STORM IS EXPECTED TO ENCOUNTER LAND AS WELL AS INCREASING WIND SHEAR...AND THERE IS SOME QUESTION THAT IT WILL EVEN SURVIVE AS IT TREKS WESTWARD TOWARD THE CARIBBEAN OR BAHAMAS...IF IT DOES SURVIVE...THE EVENTUAL PATH SEEMS PAVED FOR A TRACK INTO THE SERN US OR THE EAST COAST AS THE SUBTROPICAL RIDGE LOOKS ABNORMALLY MIGHTY FOR THIS TIME OF YEAR. STILL THE BETTER PART OF A WEEK BEFORE THAT HAPPENS. IN THE MEAN TIME A DECENT LOOKING COLD FRONT IS EXPECTED TO PASS THROUGH THE REGION ALONG ABOUT THURSDAY ASSOCIATED WITH THE UPPER TROUGH THAT IS EXPECTED TO DEVELOP OVER THE EASTERN US. IT SHOULD USHER IN SOME DRIER AIR FOR THE WEEK`S END THAT COULD LAST A DAY OR TWO BEFORE THE RIDGE REASSERTS ITSELF LOCALLY. OVERALL IT LOOKS LIKE ANOTHER VERY SUMMERY WEEK...PRETTY TYPICAL FOR EARLY JULY. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... EXPECT A WIDE RANGE OF CONDITIONS FOR ANOTHER HOUR OR SO. SOME SITES WILL BE VFR...WHILE OTHERS WILL HAVE FOG AND LOWER CIGS...IFR AT TIMES. ANY EARLY LOW CIGS/FOG SHOULD MIX OUT TO VFR CONDS BY 14Z. FOR THE REST OF MONDAY...EXPECT WIDESPREAD VFR CONDS. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING A CHC OF A BRIEF SHRA/TSRA AND ACCOMPANYING DROP IN VSBY. AS THE UPPER LVL TROUGH IS FURTHER EAST TODAY...WOULD NOT EXPECT THE WIDESPREAD SHOWERS AND STORMS THAT WE HAD ON SUNDAY. AS OF RECENT LOOPS...UPPER LVL LOW ACROSS WARREN COUNTY. WHILE NOT LOOKING FOR SEVERE STORMS TODAY OR WIDESPREAD HEAVY RAIN...HAVE TO WATCH STORMS...AS THEY WILL BE SLOW TO MOVE. LATER TONIGHT...MODELS AND DATA HINT AT MORE STORMS...MAINLY ACROSS THE FAR WEST. MORE ACTIVE WEATHER ON TUE AND WED. WED COULD FEATURE SOME STRONG STORMS...GIVEN STRONG DYNAMICS AND WARM ADVECTION. PERHAPS BETTER AVIATION WEATHER BY LATE IN THE WEEK. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
747 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER WESTERN PA. REGIONAL RADAR MOSAIC SHOWS SCATTERED CONVECTION PINWHEELING AROUND THIS FEATURE FROM OHIO TO THE MID ATL COAST. SOME SHOWERS LOOK TO BE AIMING AT FAR SERN PA FOR THE NEXT FEW HOURS...OTHERWISE THE REGION IS DRY. HIGH PRESSURE WILL REMAIN IN CONTROL FOR THE MOST PART TODAY IN THE WAKE OF THE UPPER TROF/LOW. WITH THE UPPER SYSTEM PRETTY MUCH OVERHEAD TO START THE DAY...LARGE SCALE ASCENT AND SOME MODEST INSTABILITY WILL HELP TRIGGER SOME SCATTERED SHOWERS. TIMING OF THE UPPER TROF/LOW SUGGESTS THAT MOST SHOWERS WILL BE FROM LATE MORNING THROUGH MID AFTERNOON...WITH EXPECTED RISING HEIGHTS AND MID LEVEL WARMING HELPING TO PUT A LID ON THINGS LATER IN THE DAY. THE CLOUDS AND SCATTERED SHOWERS WILL HELP LIMIT TODAY`S MAX TEMPS WITH HIGHS RANGING FROM THE MID 70S TO MID 80S FROM NW TO SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... IN THE WAKE OF OUR DEPARTING LOW...WE WILL BEGIN TO SEE THE UPPER FLOW BECOMING MORE WESTERLY WITH THE LOCAL AREA BEING CLOSE TO THE SOUTHERN EDGE OF THIS WESTERLY FLOW. FOR THE OVERNIGHT THERE IS SOME MEASURE OF AGREEMENT THAT CONVECTION CURRENTLY OVER THE WESTERN GR LAKES WILL SPILL DOWN AND COME THROUGH THE AREA LATER AT NIGHT AS AN MCS. THE SREF AND GEFS BOTH LATCH ONTO THIS...WITH SLIGHT PLACEMENT DIFFERENCES. I USED THIS TO BRING HIGHER POPS INTO THE AREA AFTER MIDNIGHT AND INTO TUESDAY MORNING. THE MODELS DIMINISH THE INSTABILITY AFTER SUNSET SO AM NOT TOO CONCERNED ABOUT LATE NIGHT SEVERE WEATHER...BUT SOME NOCTURNAL ELEVATED THUNDER LOOKS LIKE A REASONABLE POSSIBILITY. ONCE THE CONVECTION PASSES...PROBABLY BY MID TO LATE MORNING TUESDAY...THE AFTERNOON SHOULD BE RELATIVELY QUIET WITH TEMPERATURES REBOUNDING WELL INTO THE 80S REGION-WIDE...WITH THE HUMIDITY HANGING IN TOUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE PERIOD OF NEARLY ZONAL FLOW ALOFT WILL BE RELATIVELY SHORT-LIVED AS THE ROCKIES RIDGE IS EXPECTED TO EXPERIENCE A RESURGENCE...RESULTING IN THE DOWNSTREAM TROUGH DIGGING OVER THE EASTERN US. YESTERDAY`S MODEL RUNS SHOWED THE DEVELOPMENT OF A PATTERN THAT LOOKED MUCH LIKE WHAT WE WERE RECENTLY SADDLED WITH FOR OVER A WEEK WITH A DEEP LOW OVER THE TN/OH VALLEY AND A STRONG BERMUDA RIDGE NOSING INTO THE EASTERN SEABOARD KEEPING A DEEP SOUTHERLY FLOW OF TROPICAL AIR LOCKED IN OVER THE EASTERN US. THE LATEST RUNS DO CREATE AN UPPER LOW/TROUGH BUT TONIGHT THE GUIDANCE IS FASTER AND DOESN`T STALL THE LOW. INDICATIONS ARE THAT WHATEVER FORMS BETWEEN THE BERMUDA RIDGE AND THE RIDGE IN THE ROCKIES WILL BE RELATIVELY WEAK AND EITHER SETTLE SOUTH INTO THE GULF OR BECOME LOST AS A GENERAL WEAKNESS BETWEEN WHAT THE GEFS SHOWS AS A HUGE AREA OF ANOMALOUSLY HIGH HEIGHTS ASSOCIATED WITH THE SUBTROPICAL RIDGE FROM THE CENTRAL ATLANTIC ALL THE WAY WEST TO THE ROCKY MOUNTAINS BY NEXT WEEKEND. THIS IS INTERESTING FOR THE EVENTUAL DEVELOPMENTS ASSOCIATED WITH CHANTAL. WHILE THE STORM IS EXPECTED TO ENCOUNTER LAND AS WELL AS INCREASING WIND SHEAR...AND THERE IS SOME QUESTION THAT IT WILL EVEN SURVIVE AS IT TREKS WESTWARD TOWARD THE CARIBBEAN OR BAHAMAS...IF IT DOES SURVIVE...THE EVENTUAL PATH SEEMS PAVED FOR A TRACK INTO THE SERN US OR THE EAST COAST AS THE SUBTROPICAL RIDGE LOOKS ABNORMALLY MIGHTY FOR THIS TIME OF YEAR. STILL THE BETTER PART OF A WEEK BEFORE THAT HAPPENS. IN THE MEAN TIME A DECENT LOOKING COLD FRONT IS EXPECTED TO PASS THROUGH THE REGION ALONG ABOUT THURSDAY ASSOCIATED WITH THE UPPER TROUGH THAT IS EXPECTED TO DEVELOP OVER THE EASTERN US. IT SHOULD USHER IN SOME DRIER AIR FOR THE WEEK`S END THAT COULD LAST A DAY OR TWO BEFORE THE RIDGE REASSERTS ITSELF LOCALLY. OVERALL IT LOOKS LIKE ANOTHER VERY SUMMERY WEEK...PRETTY TYPICAL FOR EARLY JULY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... EXPECT A WIDE RANGE OF CONDITIONS FOR ANOTHER HOUR OR SO. SOME SITES WILL BE VFR...WHILE OTHERS WILL HAVE FOG AND LOWER CIGS...IFR AT TIMES. ANY EARLY LOW CIGS/FOG SHOULD MIX OUT TO VFR CONDS BY 14Z. FOR THE REST OF MONDAY...EXPECT WIDESPREAD VFR CONDS. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING A CHC OF A BRIEF SHRA/TSRA AND ACCOMPANYING DROP IN VSBY. AS THE UPPER LVL TROUGH IS FURTHER EAST TODAY...WOULD NOT EXPECT THE WIDESPREAD SHOWERS AND STORMS THAT WE HAD ON SUNDAY. AS OF RECENT LOOPS...UPPER LVL LOW ACROSS WARREN COUNTY. WHILE NOT LOOKING FOR SEVERE STORMS TODAY OR WIDESPREAD HEAVY RAIN...HAVE TO WATCH STORMS...AS THEY WILL BE SLOW TO MOVE. LATER TONIGHT...MODELS AND DATA HINT AT MORE STORMS...MAINLY ACROSS THE FAR WEST. MORE ACTIVE WEATHER ON TUE AND WED. WED COULD FEATURE SOME STRONG STORMS...GIVEN STRONG DYNAMICS AND WARM ADVECTION. PERHAPS BETTER AVIATION WEATHER BY LATE IN THE WEEK. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
614 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER WESTERN PA. REGIONAL RADAR MOSAIC SHOWS SCATTERED CONVECTION PINWHEELING AROUND THIS FEATURE FROM OHIO TO THE MID ATL COAST. SOME SHOWERS LOOK TO BE AIMING AT FAR SERN PA FOR THE NEXT FEW HOURS...OTHERWISE THE REGION IS DRY. HIGH PRESSURE WILL REMAIN IN CONTROL FOR THE MOST PART TODAY IN THE WAKE OF THE UPPER TROF/LOW. WITH THE UPPER SYSTEM PRETTY MUCH OVERHEAD TO START THE DAY...LARGE SCALE ASCENT AND SOME MODEST INSTABILITY WILL HELP TRIGGER SOME SCATTERED SHOWERS. TIMING OF THE UPPER TROF/LOW SUGGESTS THAT MOST SHOWERS WILL BE FROM LATE MORNING THROUGH MID AFTERNOON...WITH EXPECTED RISING HEIGHTS AND MID LEVEL WARMING HELPING TO PUT A LID ON THINGS LATER IN THE DAY. THE CLOUDS AND SCATTERED SHOWERS WILL HELP LIMIT TODAY`S MAX TEMPS WITH HIGHS RANGING FROM THE MID 70S TO MID 80S FROM NW TO SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... IN THE WAKE OF OUR DEPARTING LOW...WE WILL BEGIN TO SEE THE UPPER FLOW BECOMING MORE WESTERLY WITH THE LOCAL AREA BEING CLOSE TO THE SOUTHERN EDGE OF THIS WESTERLY FLOW. FOR THE OVERNIGHT THERE IS SOME MEASURE OF AGREEMENT THAT CONVECTION CURRENTLY OVER THE WESTERN GR LAKES WILL SPILL DOWN AND COME THROUGH THE AREA LATER AT NIGHT AS AN MCS. THE SREF AND GEFS BOTH LATCH ONTO THIS...WITH SLIGHT PLACEMENT DIFFERENCES. I USED THIS TO BRING HIGHER POPS INTO THE AREA AFTER MIDNIGHT AND INTO TUESDAY MORNING. THE MODELS DIMINISH THE INSTABILITY AFTER SUNSET SO AM NOT TOO CONCERNED ABOUT LATE NIGHT SEVERE WEATHER...BUT SOME NOCTURNAL ELEVATED THUNDER LOOKS LIKE A REASONABLE POSSIBILITY. ONCE THE CONVECTION PASSES...PROBABLY BY MID TO LATE MORNING TUESDAY...THE AFTERNOON SHOULD BE RELATIVELY QUIET WITH TEMPERATURES REBOUNDING WELL INTO THE 80S REGION-WIDE...WITH THE HUMIDITY HANGING IN TOUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE PERIOD OF NEARLY ZONAL FLOW ALOFT WILL BE RELATIVELY SHORT-LIVED AS THE ROCKIES RIDGE IS EXPECTED TO EXPERIENCE A RESURGENCE...RESULTING IN THE DOWNSTREAM TROUGH DIGGING OVER THE EASTERN US. YESTERDAY`S MODEL RUNS SHOWED THE DEVELOPMENT OF A PATTERN THAT LOOKED MUCH LIKE WHAT WE WERE RECENTLY SADDLED WITH FOR OVER A WEEK WITH A DEEP LOW OVER THE TN/OH VALLEY AND A STRONG BERMUDA RIDGE NOSING INTO THE EASTERN SEABOARD KEEPING A DEEP SOUTHERLY FLOW OF TROPICAL AIR LOCKED IN OVER THE EASTERN US. THE LATEST RUNS DO CREATE AN UPPER LOW/TROUGH BUT TONIGHT THE GUIDANCE IS FASTER AND DOESN`T STALL THE LOW. INDICATIONS ARE THAT WHATEVER FORMS BETWEEN THE BERMUDA RIDGE AND THE RIDGE IN THE ROCKIES WILL BE RELATIVELY WEAK AND EITHER SETTLE SOUTH INTO THE GULF OR BECOME LOST AS A GENERAL WEAKNESS BETWEEN WHAT THE GEFS SHOWS AS A HUGE AREA OF ANOMALOUSLY HIGH HEIGHTS ASSOCIATED WITH THE SUBTROPICAL RIDGE FROM THE CENTRAL ATLANTIC ALL THE WAY WEST TO THE ROCKY MOUNTAINS BY NEXT WEEKEND. THIS IS INTERESTING FOR THE EVENTUAL DEVELOPMENTS ASSOCIATED WITH CHANTAL. WHILE THE STORM IS EXPECTED TO ENCOUNTER LAND AS WELL AS INCREASING WIND SHEAR...AND THERE IS SOME QUESTION THAT IT WILL EVEN SURVIVE AS IT TREKS WESTWARD TOWARD THE CARIBBEAN OR BAHAMAS...IF IT DOES SURVIVE...THE EVENTUAL PATH SEEMS PAVED FOR A TRACK INTO THE SERN US OR THE EAST COAST AS THE SUBTROPICAL RIDGE LOOKS ABNORMALLY MIGHTY FOR THIS TIME OF YEAR. STILL THE BETTER PART OF A WEEK BEFORE THAT HAPPENS. IN THE MEAN TIME A DECENT LOOKING COLD FRONT IS EXPECTED TO PASS THROUGH THE REGION ALONG ABOUT THURSDAY ASSOCIATED WITH THE UPPER TROUGH THAT IS EXPECTED TO DEVELOP OVER THE EASTERN US. IT SHOULD USHER IN SOME DRIER AIR FOR THE WEEK`S END THAT COULD LAST A DAY OR TWO BEFORE THE RIDGE REASSERTS ITSELF LOCALLY. OVERALL IT LOOKS LIKE ANOTHER VERY SUMMERY WEEK...PRETTY TYPICAL FOR EARLY JULY. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... CONDITIONS CONTINUE TO GO DOWNHILL. SOME UPDATES DONE... WILL CONTINUE TO MONITOR. EXPECT A WIDE RANGE OF CONDITIONS EARLY THIS MORNING. SOME SITES WILL BE VFR...WHILE OTHERS WILL HAVE FOG AND LOWER CIGS...IFR AT TIMES. ANY EARLY LOW CIGS/FOG SHOULD MIX OUT TO VFR CONDS BY 14Z. FOR THE REST OF MONDAY...EXPECT WIDESPREAD VFR CONDS. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING A CHC OF A BRIEF SHRA/TSRA AND ACCOMPANYING DROP IN VSBY. AS THE UPPER LVL TROUGH IS FURTHER EAST TODAY...WOULD NOT EXPECT THE WIDESPREAD SHOWERS AND STORMS THAT WE HAD ON SUNDAY. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
538 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER WESTERN PA. REGIONAL RADAR MOSAIC SHOWS SCATTERED CONVECTION PINWHEELING AROUND THIS FEATURE FROM OHIO TO THE MID ATL COAST. SOME SHOWERS LOOK TO BE AIMING AT FAR SERN PA FOR THE NEXT FEW HOURS...OTHERWISE THE REGION IS DRY. HIGH PRESSURE WILL REMAIN IN CONTROL FOR THE MOST PART TODAY IN THE WAKE OF THE UPPER TROF/LOW. WITH THE UPPER SYSTEM PRETTY MUCH OVERHEAD TO START THE DAY...LARGE SCALE ASCENT AND SOME MODEST INSTABILITY WILL HELP TRIGGER SOME SCATTERED SHOWERS. TIMING OF THE UPPER TROF/LOW SUGGESTS THAT MOST SHOWERS WILL BE FROM LATE MORNING THROUGH MID AFTERNOON...WITH EXPECTED RISING HEIGHTS AND MID LEVEL WARMING HELPING TO PUT A LID ON THINGS LATER IN THE DAY. THE CLOUDS AND SCATTERED SHOWERS WILL HELP LIMIT TODAY`S MAX TEMPS WITH HIGHS RANGING FROM THE MID 70S TO MID 80S FROM NW TO SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... IN THE WAKE OF OUR DEPARTING LOW...WE WILL BEGIN TO SEE THE UPPER FLOW BECOMING MORE WESTERLY WITH THE LOCAL AREA BEING CLOSE TO THE SOUTHERN EDGE OF THIS WESTERLY FLOW. FOR THE OVERNIGHT THERE IS SOME MEASURE OF AGREEMENT THAT CONVECTION CURRENTLY OVER THE WESTERN GR LAKES WILL SPILL DOWN AND COME THROUGH THE AREA LATER AT NIGHT AS AN MCS. THE SREF AND GEFS BOTH LATCH ONTO THIS...WITH SLIGHT PLACEMENT DIFFERENCES. I USED THIS TO BRING HIGHER POPS INTO THE AREA AFTER MIDNIGHT AND INTO TUESDAY MORNING. THE MODELS DIMINISH THE INSTABILITY AFTER SUNSET SO AM NOT TOO CONCERNED ABOUT LATE NIGHT SEVERE WEATHER...BUT SOME NOCTURNAL ELEVATED THUNDER LOOKS LIKE A REASONABLE POSSIBILITY. ONCE THE CONVECTION PASSES...PROBABLY BY MID TO LATE MORNING TUESDAY...THE AFTERNOON SHOULD BE RELATIVELY QUIET WITH TEMPERATURES REBOUNDING WELL INTO THE 80S REGION-WIDE...WITH THE HUMIDITY HANGING IN TOUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE PERIOD OF NEARLY ZONAL FLOW ALOFT WILL BE RELATIVELY SHORT-LIVED AS THE ROCKIES RIDGE IS EXPECTED TO EXPERIENCE A RESURGENCE...RESULTING IN THE DOWNSTREAM TROUGH DIGGING OVER THE EASTERN US. YESTERDAY`S MODEL RUNS SHOWED THE DEVELOPMENT OF A PATTERN THAT LOOKED MUCH LIKE WHAT WE WERE RECENTLY SADDLED WITH FOR OVER A WEEK WITH A DEEP LOW OVER THE TN/OH VALLEY AND A STRONG BERMUDA RIDGE NOSING INTO THE EASTERN SEABOARD KEEPING A DEEP SOUTHERLY FLOW OF TROPICAL AIR LOCKED IN OVER THE EASTERN US. THE LATEST RUNS DO CREATE AN UPPER LOW/TROUGH BUT TONIGHT THE GUIDANCE IS FASTER AND DOESN`T STALL THE LOW. INDICATIONS ARE THAT WHATEVER FORMS BETWEEN THE BERMUDA RIDGE AND THE RIDGE IN THE ROCKIES WILL BE RELATIVELY WEAK AND EITHER SETTLE SOUTH INTO THE GULF OR BECOME LOST AS A GENERAL WEAKNESS BETWEEN WHAT THE GEFS SHOWS AS A HUGE AREA OF ANOMALOUSLY HIGH HEIGHTS ASSOCIATED WITH THE SUBTROPICAL RIDGE FROM THE CENTRAL ATLANTIC ALL THE WAY WEST TO THE ROCKY MOUNTAINS BY NEXT WEEKEND. THIS IS INTERESTING FOR THE EVENTUAL DEVELOPMENTS ASSOCIATED WITH CHANTAL. WHILE THE STORM IS EXPECTED TO ENCOUNTER LAND AS WELL AS INCREASING WIND SHEAR...AND THERE IS SOME QUESTION THAT IT WILL EVEN SURVIVE AS IT TREKS WESTWARD TOWARD THE CARIBBEAN OR BAHAMAS...IF IT DOES SURVIVE...THE EVENTUAL PATH SEEMS PAVED FOR A TRACK INTO THE SERN US OR THE EAST COAST AS THE SUBTROPICAL RIDGE LOOKS ABNORMALLY MIGHTY FOR THIS TIME OF YEAR. STILL THE BETTER PART OF A WEEK BEFORE THAT HAPPENS. IN THE MEAN TIME A DECENT LOOKING COLD FRONT IS EXPECTED TO PASS THROUGH THE REGION ALONG ABOUT THURSDAY ASSOCIATED WITH THE UPPER TROUGH THAT IS EXPECTED TO DEVELOP OVER THE EASTERN US. IT SHOULD USHER IN SOME DRIER AIR FOR THE WEEK`S END THAT COULD LAST A DAY OR TWO BEFORE THE RIDGE REASSERTS ITSELF LOCALLY. OVERALL IT LOOKS LIKE ANOTHER VERY SUMMERY WEEK...PRETTY TYPICAL FOR EARLY JULY. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... EXPECT A WIDE RANGE OF CONDITIONS OVERNIGHT. SOME SITES WILL BE VFR...WHILE OTHERS WILL HAVE FOG AND LOWER CIGS...IFR AT TIMES. A TROUGH OF LOW PRES APPROACHING FROM THE OHIO VALLEY WILL PRODUCE A FEW -SHRA ACROSS THE REGION OVERNIGHT. HOWEVER... UNLIKE LAST FEW NIGHTS...MAINLY ISOLATED WITHOUT WITH HEAVY RAIN AND THUNDER. ANY EARLY LOW CIGS/FOG SHOULD MIX OUT TO VFR CONDS BY 14Z. FOR THE REST OF MONDAY...EXPECT WIDESPREAD VFR CONDS. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING A CHC OF A BRIEF SHRA/TSRA AND ACCOMPANYING DROP IN VSBY. AS THE UPPER LVL TROUGH IS FURTHER EAST TODAY...WOULD NOT EXPECT THE WIDESPREAD SHOWERS AND STORMS THAT WE HAD ON SUNDAY. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...FITZGERALD/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
206 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST INTO THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER EASTERN OHIO. CANNOT RULE OUT THE CHANCE OF A SHOWER OR SPRINKLE OVERNIGHT AS THIS FEATURE SWINGS THROUGH...BUT HAVE DOWNPLAYED POPS OVERALL. IT`S STILL QUITE MUGGY OUT...BUT MOST PLACES ARE 5-10 COOLER TONIGHT THAN LAST NIGHT...COURTESY OF MORE CLOUDS AND SHOWERS SUNDAY THAN PREVIOUS DAYS. THIS WILL ALSO CONTRIBUTE TO MORE WIDESPREAD LOW CLOUDS AND FOG TOWARD MORNING. MINS WILL RANGE FROM THE LOWER 60S NORTHWEST TO THE UPPER 60S SOUTHEAST. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... ENSEMBLES AGREE IN SHUNTING THE AXIS OF HIGHEST PWATS EAST OF THE AREA BY MONDAY NIGHT...AND MID LEVEL HEIGHT RISES AND WARM ADVECTION SHOULD ALL COMBINE TO LIMIT OUR INSTABILITY. STILL LAPSE RATES WILL BE FAVORABLE FOR SCT SHOWERS THROUGH THE DIURNAL MAXIMUM ON MONDAY. TEMPS FROM NEAR 80 IN THE NW...TO THE MID 80S IN THE SE WILL BE VERY CLOSE TO NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AFTER THE PASSAGE OF THE UPPER LOW...THE UPPER PATTERN WILL BECOME QUASI-ZONAL FOR A TIME EARLY TO MID WEEK...WITH PA BEING ON THE SOUTHERN EDGE OF THE WESTERLIES. THE MODELS ARE CONSISTENT WITH PERSISTENT MOIST WESTERLY FLOW WHICH WILL LEAVE THE REGION VULNERABLE TO CONVECTION AS WEAK DISTURBANCES RIPPLE EASTWARD OUT OF THE MIDWEST AND GREAT LAKES. A STRONGER TROUGH WILL DEEPEN OVER SOUTHERN CANADA AND OVER THE GREAT LAKES REGION TOWARDS THE END OF THE WEEK. THIS SHOULD RESULT IN A FAIRLY STRONG FRONTAL PASSAGE SOMETIME LATER WED OR THU AS SLIGHTLY COOLER BUT MUCH DRIER AIR SLIDES OUT OF THE GR LAKES. FROM THERE THE UPPER PATTERN ADVERTISED IN SOME LONGER RANGE GUIDANCE TAKES ON A LOOK THAT IS EERILY FAMILIAR TO WHAT WE HAVE JUST EXPERIENCED...WITH A NEW CUTOFF LOW FCST TO FORM OVER THE EASTERN US...AND A RENEWED SURGE OF DEEP SOUTHERLY FLOW EVENTUALLY EXPECTED TO DEVELOP ONCE AGAIN OVER THE EASTERN US. A POTENTIAL COMPLICATING FACTOR IS A TROPICAL SYSTEM CURRENTLY WELL OUT IN THE ATLANTIC THAT THE TROPICAL MODELS TRACK INTO THE BAHAMAS BY LATE WEEK...MAKING A TANTALIZING FEATURE FOR THE EASTERN US TROF TO PERHAPS INTERACT WITH. WHAT HAS BEEN INTERESTING SO FAR THIS JULY HAS BEEN THE RATHER HIGH LATITUDE THE BERMUDA RIDGE HAS OCCUPIED FOR SO EARLY IN THE SEASON. THE LATEST PROGS ONCE AGAIN HAVE A STRONG CLOSED UPPER HIGH AT UNUSUALLY HIGH LATITUDES BY NEXT WEEKEND. IF THE TROPICAL SYSTEM CAN MANAGE TO HOLD TOGETHER...IT WOULD SUGGEST THE EASTERN SEABOARD WOULD BE VULNERABLE IN ABOUT A WEEK`S TIME. STAY TUNED. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... EXPECT A WIDE RANGE OF CONDITIONS OVERNIGHT. SOME SITES WILL BE VFR...WHILE OTHERS WILL HAVE FOG AND LOWER CIGS...IFR AT TIMES. A TROUGH OF LOW PRES APPROACHING FROM THE OHIO VALLEY WILL PRODUCE A FEW -SHRA ACROSS THE REGION OVERNIGHT. HOWEVER... UNLIKE LAST FEW NIGHTS...MAINLY ISOLATED WITHOUT WITH HEAVY RAIN AND THUNDER. ANY EARLY LOW CIGS/FOG SHOULD MIX OUT TO VFR CONDS BY 14Z. FOR THE REST OF MONDAY...EXPECT WIDESPREAD VFR CONDS. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING A CHC OF A BRIEF SHRA/TSRA AND ACCOMPANYING DROP IN VSBY. AS THE UPPER LVL TROUGH IS FURTHER EAST TODAY...WOULD NOT EXPECT THE WIDESPREAD SHOWERS AND STORMS THAT WE HAD ON SUNDAY. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...DEVOIR/LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE/GARTNER AVIATION...FITZGERALD/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
136 AM EDT MON JUL 8 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST INTO THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... UPPER LOW SHOWS UP WELL ON SATELLITE AND RUC ANALYSIS OVER EASTERN OHIO. CANNOT RULE OUT THE CHANCE OF A SHOWER OR SPRINKLE OVERNIGHT AS THIS FEATURE SWINGS THROUGH...BUT HAVE DOWNPLAYED POPS OVERALL. IT`S STILL QUITE MUGGY OUT...BUT MOST PLACES ARE 5-10 COOLER TONIGHT THAN LAST NIGHT...COURTESY OF MORE CLOUDS AND SHOWERS SUNDAY THAN PREVIOUS DAYS. THIS WILL ALSO CONTRIBUTE TO MORE WIDESPREAD LOW CLOUDS AND FOG TOWARD MORNING. MINS WILL RANGE FROM THE LOWER 60S NORTHWEST TO THE UPPER 60S SOUTHEAST. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... ENSEMBLES AGREE IN SHUNTING THE AXIS OF HIGHEST PWATS EAST OF THE AREA BY MONDAY NIGHT...AND MID LEVEL HEIGHT RISES AND WARM ADVECTION SHOULD ALL COMBINE TO LIMIT OUR INSTABILITY. STILL LAPSE RATES WILL BE FAVORABLE FOR SCT SHOWERS THROUGH THE DIURNAL MAXIMUM ON MONDAY. TEMPS FROM NEAR 80 IN THE NW...TO THE MID 80S IN THE SE WILL BE VERY CLOSE TO NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AFTER THE PASSAGE OF THE UPPER LOW...THE UPPER PATTERN WILL BECOME QUASI-ZONAL FOR A TIME EARLY TO MID WEEK...WITH PA BEING ON THE SOUTHERN EDGE OF THE WESTERLIES. THE MODELS ARE CONSISTENT WITH PERSISTENT MOIST WESTERLY FLOW WHICH WILL LEAVE THE REGION VULNERABLE TO CONVECTION AS WEAK DISTURBANCES RIPPLE EASTWARD OUT OF THE MIDWEST AND GREAT LAKES. A STRONGER TROUGH WILL DEEPEN OVER SOUTHERN CANADA AND OVER THE GREAT LAKES REGION TOWARDS THE END OF THE WEEK. THIS SHOULD RESULT IN A FAIRLY STRONG FRONTAL PASSAGE SOMETIME LATER WED OR THU AS SLIGHTLY COOLER BUT MUCH DRIER AIR SLIDES OUT OF THE GR LAKES. FROM THERE THE UPPER PATTERN ADVERTISED IN SOME LONGER RANGE GUIDANCE TAKES ON A LOOK THAT IS EERILY FAMILIAR TO WHAT WE HAVE JUST EXPERIENCED...WITH A NEW CUTOFF LOW FCST TO FORM OVER THE EASTERN US...AND A RENEWED SURGE OF DEEP SOUTHERLY FLOW EVENTUALLY EXPECTED TO DEVELOP ONCE AGAIN OVER THE EASTERN US. A POTENTIAL COMPLICATING FACTOR IS A TROPICAL SYSTEM CURRENTLY WELL OUT IN THE ATLANTIC THAT THE TROPICAL MODELS TRACK INTO THE BAHAMAS BY LATE WEEK...MAKING A TANTALIZING FEATURE FOR THE EASTERN US TROF TO PERHAPS INTERACT WITH. WHAT HAS BEEN INTERESTING SO FAR THIS JULY HAS BEEN THE RATHER HIGH LATITUDE THE BERMUDA RIDGE HAS OCCUPIED FOR SO EARLY IN THE SEASON. THE LATEST PROGS ONCE AGAIN HAVE A STRONG CLOSED UPPER HIGH AT UNUSUALLY HIGH LATITUDES BY NEXT WEEKEND. IF THE TROPICAL SYSTEM CAN MANAGE TO HOLD TOGETHER...IT WOULD SUGGEST THE EASTERN SEABOARD WOULD BE VULNERABLE IN ABOUT A WEEK`S TIME. STAY TUNED. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... A TROUGH OF LOW PRES APPROACHING FROM THE OHIO VALLEY WILL PRODUCE A FEW -SHRA ACROSS THE REGION OVERNIGHT. HOWEVER...THE BIG AVIATION CONCERN IS THE POTENTIAL OF LOW CIGS ALONG THE SPINE OF THE APPALACHIANS FROM JST NORTH THRU BFD. LATE EVENING IR LOOP ALREADY SHOWING SCT CLOUDS ACROSS THE W MTNS WITH BASES ARND 1500FT AND AS BLYR COOLS/MOISTENS CIGS BLW 1KFT COULD DEVELOP. LATEST SREF AND RAP OUTPUT BOTH SUPPORT THIS POTENTIAL OF IFR CONDS ACROSS THE W MTNS...BUT NOT CERTAIN ENOUGH TO INCLUDE IN FCST YET. FURTHER EAST...FOG IS CERTAINLY A POSSIBILITY...GIVEN THE WET GROUND AND PARTIAL CLEARING EXPECTED LATE TONIGHT. HOWEVER...PRES GRADIENT SUGGESTS THERE WILL BE ENOUGH OF A WIND TO PRECLUDE IFR VSBYS. BELIEVE THE 800 FT CIG AT IPT AT 03Z IS A TEMPORARY CONDITION AND ENOUGH OF A BREEZE WILL DEVELOP OVERNIGHT TO PRECLUDE LOW CIGS THERE FOR THE BALANCE OF THE NIGHT. ANY EARLY LOW CIGS/FOG SHOULD MIX OUT TO VFR CONDS ARND 12Z. FOR THE REST OF MONDAY...EXPECT WIDESPREAD VFR CONDS. HOWEVER...PASSAGE OF UPPER LVL TROUGH WILL BRING THE CHC OF A BRIEF SHRA/TSRA AND ACCOMPANYING DROP IN VSBY. OUTLOOK... TUE...AM SHRA/LOW CIGS POSS W MTNS. WED-THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSS...MAINLY PM. FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...DEVOIR/LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE/GARTNER AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
356 PM CDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 ATTENTION IN THE SHORT TERM IS ON THE CONVECTIVE DEVELOPMENT. OUTFLOW/FRONTAL HYBRID REMAINS DISTINCT ACROSS WESTERN IOWA JUST ALONG THE SOUTHERN EDGE OF THE CWA...BUT MORE DIFFUSE HEADING WEST INTO NEBRASKA. MCV PASSING SOUTH OF CWA...AND RECENTLY HAVE SEEN LONE CONVECTIVE CELL DEVELOP ALONG THIS BOUNDARY NEAR CWA BORDER... AND NOT SURPRISED WITH RAP ANALYSIS INDICATING WEAKENED /MORE LIKELY WEAKENING/ CAP. LIKELY THAT MOST AREAS AT LEAST A WEAK CAP REMAINS /ON ORDER OF A SKINNY 20-40 J/KG/ IF SOME PRECONVECTED MODELS USED FOR GUIDANCE. NO QUESTION ATMOSPHERE IS CERTAINLY LOADING UP ON POTENTIAL ENERGY THIS AFTERNOON...BUT SOMEWHAT LESS OUT IN THE FAR WEST WHERE HAVE BEEN ALONG EDGE OF NAGGING CIRRUS SHIELD FROM EARLIER DAY ACTIVITY. THE AREA ACROSS NORTHWEST IOWA WILL BE ONE AREA OF CONVECTIVE THREAT FOR THE LATE AFTERNOON AND EARLY EVENING... AND THREATS THERE WILL BALANCE BETWEEN QUARTER TO HALF DOLLAR HAIL... AND DAMAGING WIND GUSTS. ALSO MUST NOT FORGET THAT FAIRLY WEAK WINDS ALONG WITH RIGHT MOVING SUPERCELL MOTION OF 5 TO 10 KNOTS MAXIMUM THROUGH EARLY EVENING...WITH WARM CLOUD DEPTHS OVER 12 KFT...FLASH FLOODING IS A RISK. EFFECTIVELY SHEAR IS IN THAT 30-40 KNOT RANGE...AND CERTAINLY IN THE REALM WHERE SUERCELLS WOULD CERTAINLY BE POSSIBLE...OR AT LEAST HYBRID WITH LINEAR/BOWING STRUCTURE. LOWER TO MID LEVEL STORM RELATIVE INFLOW FAIRLY BALANCED...SO MAY END UP WITH A FAIRLY STABLE BOWING STRUCTURE...AND SOMETHING TOWARD A HIGHER END DAMAGING WIND EVENT IS NOT OUT OF THE QUESTION. MOST HIGH RESOLUTION GUIDANCE IS SUPPORTIVE OF THIS MODE...AND LITTLE REASON TO DOUBT IT. FOR NOW... MOST LIKELY AREA WOULD APPEAR TO BE NEAR/SOUTH OF INTERSTATE 90 FROM THE EARLY EVENING HOURS NEAR 9V9...AROUND MIDNIGHT CLOSER TO I29...AND A BIT LATER THROUGH NW IA. IN THE WAKE OF THE MCS...WILL AGAIN BE POTENTIAL FOR SOME PATCHY FOG WHERE SKIES CAN CLEAR...AND ADDED SMALL MENTION FOR AREAS GENERALLY NEAR/SOUTH OF I90 AND NEAR/WEST OF I29. AFTER THE ATMOSPHERE BEING WORKED OVER TONIGHT...VEERING LOW LEVEL JET SHOULD QUICKLY END EARLY DAY ACTION EAST...WITH TEMPS CONTINUING TO WARM ALOFT AHEAD OF FAIRLY STRONG UPPER ENERGY...WHICH WILL SWING SOUTHEAST ACROSS THE AREA ON TUESDAY AFTERNOON. AT THE SURFACE... OUTFLOW/CONVERGENCE BOUNDARY SHOULD BE LEADING THE AREA ACROSS NORTHWEST IOWA BY MIDDAY... HOWEVER...THE STRONGER BOUNDARY/MOISTURE DISCONTINUITY WILL BE TIED TO THE UPPER ENERGY. AREAS BETWEEN THE BOUNDARIES WILL CONTINUE STIFLING HUMIDITY AND HAVE MUCH OF NW IA REACHING HEAT INDEX VALUES FROM 100 TO 105 FROM MIDDAY TOMORROW THROUGH MUCH OF THE AFTERNOON. LIKELY TO REMAIN FAIRLY CAPPED UNTIL LIFT FROM APPROACHING FRONT AND COOLING TEMPS ALOFT WITH UPPER WAVE. EFFECTIVE SHEAR LOOKS TO BE A BIT STRONGER AND QUITE LINEAR...AND A SEVERE RISK OVER THE SOUTHEASTERN 2/3 OF THE AREA LOOKS WARRANTED GIVEN THE DEGREE OF POTENTIAL INSTABILITY AND EFFECTIVE SHEAR. THREAT WOULD AGAIN BE PRIMARILY HAIL AND DAMAGING WIND. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 THE SHORTWAVE AND FRONTAL BOUNDARY WILL TRACK OFF TO THE EAST BY TUESDAY EVENING...WITH ANY LINGERING THUNDERSTORM ACTIVITY FOLLOWING SUIT. WITH DECENT COLD AIR ADVECTION AND DRYING BEHIND THE EXITING SYSTEM...IT WILL BE A COOLER NIGHT WITH LOWERING DEW POINTS. LOWS WILL BOTTOM OUT IN THE UPPER 50S TO LOWER 60S BY EARLY WEDNESDAY MORNING. A SURFACE RIDGE SLIDES SOUTHWARD THROUGH THE REGION ON WEDNESDAY...PROVIDING FOR A PLEASANT DAY WITH LIGHT WINDS AND DEW POINTS DOWN INTO THE 50S. HIGHS WILL BE SEASONABLE FOR THIS TIME OF YEAR WITH READINGS IN THE UPPER 70S TO LOWER 80S. THURSDAY ALSO LOOKS TO BE A DECENT DAY...ALBEIT WARMER AS HIGH PRESSURE BEGINS TO MOVE OFF TO THE EAST AND A SOUTHERLY FLOW RETURNS TO THE REGION. WITH 850 MB TEMPERATURES CLIMBING AROUND 3 DEGREES OVER WEDNESDAY...HIGHS WILL RISE INTO THE LOWER 80S EAST TO NEAR 90 THROUGH SOUTH CENTRAL SOUTH DAKOTA. IN THE EXTENDED...UPPER LEVEL RIDGE BUILDS INTO THE REGION THROUGH THE END OF THE WEEK...TRANSITIONING TO A MORE WEST-EAST FLOW BY THE START OF NEXT WEEK. THIS WILL BRING A CONTINUED WARM UP INTO SUNDAY...THEN SOME COOLING POSSIBLE BY MONDAY. AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE THROUGH THE PERIOD...CONVECTION CHANCES WILL INCREASE FOR THE WEEKEND...WITH TYPICAL MODEL DIFFERENCES IN TIMING/PLACEMENT OF CONVECTION. HIGHS INTO THE WEEKEND LOOK TO GENERALLY BE IN THE MID 80S TO LOWER 90S...WITH LOWS UPPER 60S TO LOWER 70S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 112 PM CDT MON JUL 8 2013 MAIN AVIATION CONCERN FOR THE MIDDAY PACKAGE IS THE DEVELOPMENT OF CONVECTION. EXPECTATIONS ARE FOR MOST SIGNIFICANT CONVECTION WILL DEVELOP ACROSS WESTERN SOUTH DAKOTA AND PROGRESS EASTWARD THROUGH THE EVENING AND EARLY OVERNIGHT HOURS...PRESENTING GENERALLY A DAMAGING WIND AND MARGINALLY LARGE HAIL THREAT SOUTH OF INTERSTATE 90. OTHER MORE ISOLATED STORMS MAY DEVELOP BY LATE AFTERNOON IN PROXIMITY TO CUMULUS FIELD DEVELOPING SOUTH OF INTERSTATE 90... AND EXTENDING INTO NW IA. THESE STORMS WOULD BRING A LARGE HAIL AND DAMAGING WIND THREAT. DAMAGING WIND GUSTS UP TO 80 MPH WILL BE POSSIBLE WITH ORGANIZED BOWING SYSTEM...A MODE SUGGESTED BY SEVERAL HIGH RESOLUTION MODELS. THUNDERSTORMS WILL LIKELY CONTAIN PERIODS OF MVFR TO IFR CONDITIONS. POSSIBILITY FOR SOME AREAS IN WAKE OF MCS TO DEVELOP SOME MVFR FOG LATE NIGHT OR EARLY MORNING...BUT FOR NOW MENTIONED ONLY A LITTLE AROUND KFSD. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN LONG TERM...JM AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
229 PM CDT MON JUL 8 2013 .DISCUSSION... AN UPPER LEVEL DISTURBANCE PASSING BY TO THE SOUTH ACROSS THE BIG BEND COULD GENERATE ISOLATED THUNDERSTORMS THIS EVENING ACROSS WEST TEXAS PER CUMULUS FIELD AND LATEST RUC GUIDANCE. ANY ACTIVITY SHOULD DIE THIS EVENING WITH LOSS OF HEATING. THIS DISTURBANCE IS FORECAST TO CONTINUE TO SLOWLY TRACK WESTWARD ACROSS NORTHERN MEXICO TUESDAY AND TUESDAY EVENING WITH ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE AGAIN ACROSS THE BIG BEND...DAVIS MOUNTAINS AND LOWER TRANS PECOS REGION CLOSEST TO THE TRACK OF DISTURBANCE. BEYOND TUESDAY A SPRAWLING UPPER LEVEL HIGH PRESSURE AREA ACROSS THE PLAINS AND ROCKIES SHOULD REGAIN FIRM CONTROL OF THE REGION AND PRECIPITATION CHANCES WILL BE VERY LOW. THE NEXT CHANCE OF CONVECTION APPEARS TO BE NEXT SUNDAY AND MONDAY AS ANOTHER DISTURBANCE TRACKS WESTWARD ACROSS THE GULF AND MEXICO. HIGH TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL THROUGH WEDNESDAY WITH ABOVE NORMAL TEMPERATURES EXPECTED THURSDAY THROUGH SATURDAY. && .PRELIMINARY POINT TEMPS/POPS... ANDREWS TX 68 94 71 96 / 10 10 0 0 BIG SPRING TX 70 94 72 96 / 10 10 0 0 CARLSBAD NM 67 95 68 97 / 10 10 0 0 DRYDEN TX 72 94 71 96 / 10 20 10 0 FORT STOCKTON TX 71 93 72 96 / 10 10 10 10 GUADALUPE PASS TX 66 86 67 88 / 10 10 10 10 HOBBS NM 65 93 70 95 / 10 0 0 0 MARFA TX 63 86 59 88 / 10 20 10 20 MIDLAND INTL AIRPORT TX 71 94 71 96 / 10 10 0 0 ODESSA TX 70 94 72 96 / 10 10 0 0 WINK TX 72 96 73 99 / 10 10 10 0 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 44/12
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1011 AM CDT MON JUL 8 2013 UPDATE... THE MUCH NEEDED AND ANTICIPATED RAINFALL AND ITS RECENT BEHAVIOR HAS CERTAINLY SEPARATED THE HAVE AND THE HAVE NOTS WITH SOME COUNTIES...SUCH AS JACKSON AND WHARTON...RECEIVING OVER AN INCH OR TWO WHILE MOST OTHERS HAVE BEEN FORTUNATE TO HAVE ONLY PICKED UP A FEW HUNDREDTHS OF AN INCH (OR LESS). MOISTURE DEFINITELY HAS NOT BEEN A PROBLEM...THE TROPICAL AIR MASS OVER THE CWA IS GREATER THAN 2 INCHES (75 PERCENTILE FOR EARLY JULY) WITH THE DEEPEST REGIONAL MOISTURE UP THROUGH 700 MB CENTERED RIGHT OVER SOUTHEASTERN TEXAS. WITH NO SIGNIFICANT TRIGGER (UPSTREAM DISTURBANCE OR RESIDUAL BOUNDARIES) TO INITIATE BETTER CONVECTIVE AREAL COVERAGE...THE RAGGED NATURE OF THIS MORNING`S ACTIVITY WILL HAVE TO RELY UPON INSOLATION FOR SUSTAINABILITY. AS THE SUN ROSE TO MOSTLY CLOUDY CONDITIONS...MODEST CHANCE MORNING POPS WILL SHARPLY DECLINE THROUGH THE AFTERNOON. COLUMN WILL BEGIN TO DRY OUT PER THE SOUTHERN TRANSPORT OF A DRIER AIR MASS INLAND...UPPER 90 CONVECTIVE TEMPERATURES WILL BE HARD TO REACH PER THIS EARLY DAY CLOUD DECK. THE 594 DAM UPPER RIDGE CENTERED OVER NORTHERN TEXAS WILL BE WHAT CONTROLS OUR WEATHER PATTERN IN THE FORESEEABLE FUTURE. HEAT AND THE LACK OF RAIN WILL BE THE TOPICS DU JOUR. 31 && PREV DISCUSSION... /ISSUED 619 AM CDT MON JUL 8 2013/ AVIATION... SHOWERS FILLING IN ACROSS THE WESTERN THIRD OF THE REGION WITH SOME ADDITIONAL ACTIVITY MOVING IN FROM THE GULF OF MEXICO. BEST COVERAGE WILL REMAIN WEST OF THE TAF SITES BUT WILL CARRY VCSH FOR MOST OF THE MORNING BEFORE DRIER AIR BEGINS TO MOVE INTO THE REGION. MODELS ARE HINTING AT THE POTENTIAL FOR SOME MVFR/IFR CIGS AROUND DAYBREAK ON TUESDAY BUT THIS SEEMS A BIT AGGRESSIVE. WILL PUT SOME LOW CLOUDS INTO THE TAF BUT HAVE HELD OFF ON ANY CIGS FOR THIS ISSUANCE. 38 && PREV DISCUSSION... /ISSUED 430 AM CDT MON JUL 8 2013/ DISCUSSION... THE FORECAST HAS BEEN FRUSTRATING THE LAST 24 HOURS GIVEN THE PROSPECTS OF RAIN CHANCES FOR YESTERDAY. GOES SOUNDER PRECIP WATER AND 00Z SOUNDINGS FROM CRP AND LCH SHOW THAT A TROPICAL AIRMASS WITH PW AROUND 2.2 INCHES HAS MOVED OVER SE TX. DESPITE THAT THERE HAS BEEN VERY LITTLE SIGNIFICANT RAINFALL ACROSS THE AREA. IT SEEMS THAT THE UPPER LEVEL PATTERN HAS NOT BEEN SUPPORTIVE OF CONVECTION IN HIND SIGHT. THE LAST COUPLE OF DAYS HAVE FEATURED A SHEAR AXIS OVER THE AREA WITH AN UPPER LEVEL RIDGE EXPANDING INTO THE PLAINS AS AN UPPER LOW EXITS THE REGION TOWARDS THE GREAT LAKES. SEEMS LIKE THE SHEAR AXIS DID NOT WEAKEN AS MUCH AS THE MODELS SUGGESTED AND WHEN IT DID...SUBSIDENCE FROM THE RIDGE WAS APPARENTLY STRONG ENOUGH TO LIMIT CONVECTION. GOING FORWARD TO TODAY...THINK WE WILL SEE MUCH OF THE SAME. UPPER AIR ANALYSIS STILL HAS A DECENT RIDGE OVER THE S PLAINS AND S ROCKIES. FORECAST WILL STILL KEEP SOME 30/40 POPS FOR THIS MORNING AS EXPECT THERE TO BE AT LEAST SOME CONVECTION WITH DAYTIME HEATING. THE PROBLEM IS THAT GOES SOUNDER DATA DOES SHOW DRIER AIR IN THE GULF WITH PRECIP WATER VALUES NEAR 1.6 INCHES THAT THE MODELS FORECAST TO MOVE INTO THE REGION LATER TODAY. WITH THAT IN MIND...WILL DROP POPS TO 30 PERCENT IN THE AFTERNOON BUT THINK THAT MAY EVEN BE OPTIMISTIC. HRRR MESOSCALE MODEL SHOWS SIMILAR EVOLUTION OF CONVECTION WITH MOST OF THE ACTIVITY OCCURRING IN THE LATE MORNING/EARLY AFTERNOON HOURS. EVEN WRF-NMM SHOWS CONVECTIVE TRENDS SIMILAR TO THIS THINKING. DEEPER MOISTURE WILL BE RATHER TRANSIENT TUE/WED. AGAIN THINK THE RIDGE WILL BE THE MAIN PROBLEM INHIBITING CONVECTION. THAT SAID...MAY GET ENOUGH MOISTURE MAINLY ON WED TO GET A FEW STORMS AND ENOUGH REASON TO KEEP 20/30 POPS IN THE FORECAST. BY THE END OF THE WEEK THE RIDGE LOOKS TO EXPAND AND STRENGTHEN OVER THE ROCKIES AND PLAINS. WITH LESS MOISTURE...DO NOT THINK THERE WILL BE ANY RAIN CHANCES FOR THUR/FRI/SAT. ALSO SEE MAX TEMPS GETTING INTO THE UPPER 90S PERHAPS A FEW 100S FOR THE NORTHERN COUNTIES OF THE FORECAST AREA DUE TO THE RIDGE. BOTH THE GFS/ECMWF HAVE BEEN HINTING AT A TROUGH/UPPER LOW DEVELOPING OVER THE APPALACHIANS AND THEN RETROGRADING INTO THE AREA. GFS GOES AS FAR AS TO PUSH WEAK BACK DOOR FRONT INTO THE AREA. THINK THIS MAY BE A BIT AGGRESSIVE AND TRENDED THE FORECAST CLOSER TO THE ECMWF SOLUTION. ECMWF HAS THE FRONT STALLING WELL BEFORE REACHING SE TX AND HAS MORE OF AN ELONGATED TROUGH STRETCHING INTO THE AREA FOR NEXT WEEKEND. GIVEN LOWER HEIGHTS...DECIDED 20 POPS MAY BE NEEDED WITH THE INFLUENCE OF THE RIDGE MORE OVER THE C PLAINS. DID NOT TRIM BACK MAX TEMPS TOO MUCH BUT STILL A COUPLE OF DEGREES ABOVE GFS GUIDANCE. 39 && MARINE... WINDS HAVE PICKED UP A BIT ACROSS THE FAR OFFSHORE WATERS WITH SEAS SILL RUNNING AROUND 5 FEET. WILL CONTINUE THE SCEC THROUGH MID MORNING BUT OVERALL TREND EXPECTED TO BE A LOWERING OF SEAS THROUGH THE MORNING HOURS. SCATTERED SHOWERS EXPECTED TO DEVELOP THIS MORNING AS A WEAK UPPER DISTURBANCE PASSES OVERHEAD. EXPECT DECREASING COVERAGE ACROSS THE COASTAL WATERS FOR THE AFTERNOON AND EVENING HOURS TODAY. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 97 75 98 76 98 / 30 10 10 10 20 HOUSTON (IAH) 94 76 95 76 96 / 50 10 20 20 30 GALVESTON (GLS) 89 81 91 81 91 / 20 10 20 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 1 PM CDT THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...31/43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
950 AM CDT MON JUL 8 2013 .UPDATE... THE MUCH NEEDED AND ANTICIPATED RAINFALL AND ITS RECENT BEHAVIOR HAS CERTAINLY SEPARATED THE HAVE AND THE HAVE NOTS WITH SOME COUNTIES...SUCH AS JACKSON AND WHARTON...RECEIVING OVER AN INCH OR TWO WHILE MOST OTHERS HAVE BEEN FORTUNATE TO HAVE ONLY PICKED UP A FEW HUNDREDTHS OF AN INCH (OR LESS). MOISTURE DEFINITELY HAS NOT BEEN A PROBLEM...THE TROPICAL AIR MASS OVER THE CWA IS GREATER THAN 2 INCHES (75 PERCENTILE FOR EARLY JULY) WITH THE DEEPEST REGIONAL MOISTURE UP THROUGH 700 MB CENTERED RIGHT OVER SOUTHEASTERN TEXAS. WITH NO SIGNIFICANT TRIGGER (UPSTREAM DISTURBANCE OR RESIDUAL BOUNDARIES) TO INITIATE BETTER CONVECTIVE AREAL COVERAGE...THE RAGGED NATURE OF THIS MORNING`S ACTIVITY WILL HAVE TO RELY UPON INSOLATION FOR SUSTAINABILITY. AS THE SUN ROSE TO MOSTLY CLOUDY CONDITIONS...MODEST CHANCE MORNING POPS WILL SHARPLY DECLINE THROUGH THE AFTERNOON. COLUMN WILL BEGIN TO DRY OUT PER THE SOUTHERN TRANSPORT OF A DRIER AIR MASS INLAND...UPPER 90 CONVECTIVE TEMPERATURES WILL BE HARD TO REACH PER THIS EARLY DAY CLOUD DECK. THE 594 DAM UPPER RIDGE CENTERED OVER NORTHERN TEXAS WILL BE WHAT CONTROLS OUR WEATHER PATTERN IN THE FORESEEABLE FUTURE. HEAT AND THE LACK OF RAIN WILL BE THE TOPICS DU JOUR. 31 && .PREV DISCUSSION... /ISSUED 619 AM CDT MON JUL 8 2013/ AVIATION... SHOWERS FILLING IN ACROSS THE WESTERN THIRD OF THE REGION WITH SOME ADDITIONAL ACTIVITY MOVING IN FROM THE GULF OF MEXICO. BEST COVERAGE WILL REMAIN WEST OF THE TAF SITES BUT WILL CARRY VCSH FOR MOST OF THE MORNING BEFORE DRIER AIR BEGINS TO MOVE INTO THE REGION. MODELS ARE HINTING AT THE POTENTIAL FOR SOME MVFR/IFR CIGS AROUND DAYBREAK ON TUESDAY BUT THIS SEEMS A BIT AGGRESSIVE. WILL PUT SOME LOW CLOUDS INTO THE TAF BUT HAVE HELD OFF ON ANY CIGS FOR THIS ISSUANCE. 38 PREV DISCUSSION... /ISSUED 430 AM CDT MON JUL 8 2013/ DISCUSSION... THE FORECAST HAS BEEN FRUSTRATING THE LAST 24 HOURS GIVEN THE PROSPECTS OF RAIN CHANCES FOR YESTERDAY. GOES SOUNDER PRECIP WATER AND 00Z SOUNDINGS FROM CRP AND LCH SHOW THAT A TROPICAL AIRMASS WITH PW AROUND 2.2 INCHES HAS MOVED OVER SE TX. DESPITE THAT THERE HAS BEEN VERY LITTLE SIGNIFICANT RAINFALL ACROSS THE AREA. IT SEEMS THAT THE UPPER LEVEL PATTERN HAS NOT BEEN SUPPORTIVE OF CONVECTION IN HIND SIGHT. THE LAST COUPLE OF DAYS HAVE FEATURED A SHEAR AXIS OVER THE AREA WITH AN UPPER LEVEL RIDGE EXPANDING INTO THE PLAINS AS AN UPPER LOW EXITS THE REGION TOWARDS THE GREAT LAKES. SEEMS LIKE THE SHEAR AXIS DID NOT WEAKEN AS MUCH AS THE MODELS SUGGESTED AND WHEN IT DID...SUBSIDENCE FROM THE RIDGE WAS APPARENTLY STRONG ENOUGH TO LIMIT CONVECTION. GOING FORWARD TO TODAY...THINK WE WILL SEE MUCH OF THE SAME. UPPER AIR ANALYSIS STILL HAS A DECENT RIDGE OVER THE S PLAINS AND S ROCKIES. FORECAST WILL STILL KEEP SOME 30/40 POPS FOR THIS MORNING AS EXPECT THERE TO BE AT LEAST SOME CONVECTION WITH DAYTIME HEATING. THE PROBLEM IS THAT GOES SOUNDER DATA DOES SHOW DRIER AIR IN THE GULF WITH PRECIP WATER VALUES NEAR 1.6 INCHES THAT THE MODELS FORECAST TO MOVE INTO THE REGION LATER TODAY. WITH THAT IN MIND...WILL DROP POPS TO 30 PERCENT IN THE AFTERNOON BUT THINK THAT MAY EVEN BE OPTIMISTIC. HRRR MESOSCALE MODEL SHOWS SIMILAR EVOLUTION OF CONVECTION WITH MOST OF THE ACTIVITY OCCURRING IN THE LATE MORNING/EARLY AFTERNOON HOURS. EVEN WRF-NMM SHOWS CONVECTIVE TRENDS SIMILAR TO THIS THINKING. DEEPER MOISTURE WILL BE RATHER TRANSIENT TUE/WED. AGAIN THINK THE RIDGE WILL BE THE MAIN PROBLEM INHIBITING CONVECTION. THAT SAID...MAY GET ENOUGH MOISTURE MAINLY ON WED TO GET A FEW STORMS AND ENOUGH REASON TO KEEP 20/30 POPS IN THE FORECAST. BY THE END OF THE WEEK THE RIDGE LOOKS TO EXPAND AND STRENGTHEN OVER THE ROCKIES AND PLAINS. WITH LESS MOISTURE...DO NOT THINK THERE WILL BE ANY RAIN CHANCES FOR THUR/FRI/SAT. ALSO SEE MAX TEMPS GETTING INTO THE UPPER 90S PERHAPS A FEW 100S FOR THE NORTHERN COUNTIES OF THE FORECAST AREA DUE TO THE RIDGE. BOTH THE GFS/ECMWF HAVE BEEN HINTING AT A TROUGH/UPPER LOW DEVELOPING OVER THE APPALACHIANS AND THEN RETROGRADING INTO THE AREA. GFS GOES AS FAR AS TO PUSH WEAK BACK DOOR FRONT INTO THE AREA. THINK THIS MAY BE A BIT AGGRESSIVE AND TRENDED THE FORECAST CLOSER TO THE ECMWF SOLUTION. ECMWF HAS THE FRONT STALLING WELL BEFORE REACHING SE TX AND HAS MORE OF AN ELONGATED TROUGH STRETCHING INTO THE AREA FOR NEXT WEEKEND. GIVEN LOWER HEIGHTS...DECIDED 20 POPS MAY BE NEEDED WITH THE INFLUENCE OF THE RIDGE MORE OVER THE C PLAINS. DID NOT TRIM BACK MAX TEMPS TOO MUCH BUT STILL A COUPLE OF DEGREES ABOVE GFS GUIDANCE. 39 MARINE... WINDS HAVE PICKED UP A BIT ACROSS THE FAR OFFSHORE WATERS WITH SEAS SILL RUNNING AROUND 5 FEET. WILL CONTINUE THE SCEC THROUGH MID MORNING BUT OVERALL TREND EXPECTED TO BE A LOWERING OF SEAS THROUGH THE MORNING HOURS. SCATTERED SHOWERS EXPECTED TO DEVELOP THIS MORNING AS A WEAK UPPER DISTURBANCE PASSES OVERHEAD. EXPECT DECREASING COVERAGE ACROSS THE COASTAL WATERS FOR THE AFTERNOON AND EVENING HOURS TODAY. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 97 75 98 76 98 / 30 10 10 10 20 HOUSTON (IAH) 94 76 95 76 96 / 30 10 20 20 30 GALVESTON (GLS) 89 81 91 81 91 / 20 10 20 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 11 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
430 AM CDT MON JUL 8 2013 .DISCUSSION... THE FORECAST HAS BEEN FRUSTRATING THE LAST 24 HOURS GIVEN THE PROSPECTS OF RAIN CHANCES FOR YESTERDAY. GOES SOUNDER PRECIP WATER AND 00Z SOUNDINGS FROM CRP AND LCH SHOW THAT A TROPICAL AIRMASS WITH PW AROUND 2.2 INCHES HAS MOVED OVER SE TX. DESPITE THAT THERE HAS BEEN VERY LITTLE SIGNIFICANT RAINFALL ACROSS THE AREA. IT SEEMS THAT THE UPPER LEVEL PATTERN HAS NOT BEEN SUPPORTIVE OF CONVECTION IN HIND SIGHT. THE LAST COUPLE OF DAYS HAVE FEATURED A SHEAR AXIS OVER THE AREA WITH AN UPPER LEVEL RIDGE EXPANDING INTO THE PLAINS AS AN UPPER LOW EXITS THE REGION TOWARDS THE GREAT LAKES. SEEMS LIKE THE SHEAR AXIS DID NOT WEAKEN AS MUCH AS THE MODELS SUGGESTED AND WHEN IT DID...SUBSIDENCE FROM THE RIDGE WAS APPARENTLY STRONG ENOUGH TO LIMIT CONVECTION. GOING FORWARD TO TODAY...THINK WE WILL SEE MUCH OF THE SAME. UPPER AIR ANALYSIS STILL HAS A DECENT RIDGE OVER THE S PLAINS AND S ROCKIES. FORECAST WILL STILL KEEP SOME 30/40 POPS FOR THIS MORNING AS EXPECT THERE TO BE AT LEAST SOME CONVECTION WITH DAYTIME HEATING. THE PROBLEM IS THAT GOES SOUNDER DATA DOES SHOW DRIER AIR IN THE GULF WITH PRECIP WATER VALUES NEAR 1.6 INCHES THAT THE MODELS FORECAST TO MOVE INTO THE REGION LATER TODAY. WITH THAT IN MIND...WILL DROP POPS TO 30 PERCENT IN THE AFTERNOON BUT THINK THAT MAY EVEN BE OPTIMISTIC. HRRR MESOSCALE MODEL SHOWS SIMILAR EVOLUTION OF CONVECTION WITH MOST OF THE ACTIVITY OCCURRING IN THE LATE MORNING/EARLY AFTERNOON HOURS. EVEN WRF-NMM SHOWS CONVECTIVE TRENDS SIMILAR TO THIS THINKING. DEEPER MOISTURE WILL BE RATHER TRANSIENT TUE/WED. AGAIN THINK THE RIDGE WILL BE THE MAIN PROBLEM INHIBITING CONVECTION. THAT SAID...MAY GET ENOUGH MOISTURE MAINLY ON WED TO GET A FEW STORMS AND ENOUGH REASON TO KEEP 20/30 POPS IN THE FORECAST. BY THE END OF THE WEEK THE RIDGE LOOKS TO EXPAND AND STRENGTHEN OVER THE ROCKIES AND PLAINS. WITH LESS MOISTURE...DO NOT THINK THERE WILL BE ANY RAIN CHANCES FOR THUR/FRI/SAT. ALSO SEE MAX TEMPS GETTING INTO THE UPPER 90S PERHAPS A FEW 100S FOR THE NORTHERN COUNTIES OF THE FORECAST AREA DUE TO THE RIDGE. BOTH THE GFS/ECMWF HAVE BEEN HINTING AT A TROUGH/UPPER LOW DEVELOPING OVER THE APPALACHIANS AND THEN RETROGRADING INTO THE AREA. GFS GOES AS FAR AS TO PUSH WEAK BACK DOOR FRONT INTO THE AREA. THINK THIS MAY BE A BIT AGGRESSIVE AND TRENDED THE FORECAST CLOSER TO THE ECMWF SOLUTION. ECMWF HAS THE FRONT STALLING WELL BEFORE REACHING SE TX AND HAS MORE OF AN ELONGATED TROUGH STRETCHING INTO THE AREA FOR NEXT WEEKEND. GIVEN LOWER HEIGHTS...DECIDED 20 POPS MAY BE NEEDED WITH THE INFLUENCE OF THE RIDGE MORE OVER THE C PLAINS. DID NOT TRIM BACK MAX TEMPS TOO MUCH BUT STILL A COUPLE OF DEGREES ABOVE GFS GUIDANCE. 39 && .MARINE... WINDS HAVE PICKED UP A BIT ACROSS THE FAR OFFSHORE WATERS WITH SEAS SILL RUNNING AROUND 5 FEET. WILL CONTINUE THE SCEC THROUGH MID MORNING BUT OVERALL TREND EXPECTED TO BE A LOWERING OF SEAS THROUGH THE MORNING HOURS. SCATTERED SHOWERS EXPECTED TO DEVELOP THIS MORNING AS A WEAK UPPPER DISTURBANCE PASSES OVERHEAD. EXPECT DECREASING COVERAGE ACROSS THE COASTAL WATERS FOR THE AFTERNOON AND EVENING HOURS TODAY. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 96 75 97 76 98 / 30 10 10 10 20 HOUSTON (IAH) 93 76 95 76 95 / 40 10 20 20 30 GALVESTON (GLS) 89 81 91 81 91 / 40 10 20 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 11 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...39 AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS SPOKANE WA
227 PM PDT Mon Jul 8 2013 .SYNOPSIS... A weather system passing through the Inland Northwest today will promote scattered showers and thunderstorms across the northern mountains of Washington and Idaho, as well as southeast Washington. Tuesday and Wednesday will be the warmest days this week with high temperatures in the upper 80s to mid 90s. Thursday through Saturday will be occasionally breezy with temperatures pretty close to average, or slightly below. Low shower and thunderstorms chances will linger near the mountains, especially closer to the Canadian border, but otherwise conditions will be dry. Temperatures begin to warm up again slightly going into early next week. && .DISCUSSION... This Afternoon and Evening: The weather over northeast Washington and the Idaho Panhandle will be active. Scattered thunderstorms are expected through early this evening. Our concern area extends from the Okanogan Highlands through northeast Washington into the northern and central Idaho Panhandle. The 2 PM visible imagery shows a mid-level atmospheric circulation in far southeast British Columbia slowly moving east. Around this circulation the atmosphere has become increasingly unstable with the RUC analysis indicating 500 to 1000 J/KG of surface based CAPE from Republic to Sandpoint to Spokane to Kellogg. Very little convective inhibition remains, so look for convection to continue to develop through late afternoon. Shear and buoyancy values suggest the potential for organized multi-cell thunderstorms. Our main threat through 6 PM will be the potential for hail, heavy rain, and gusty winds. A couple severe thunderstorm warnings may be needed, but most of the cells through early evening will probably pulse up, produce hail up to dime size, then pulse down. The threat for thunderstorms should dissipate quickly early this evening as the upper level support (upper low in SE BC) moves east of the region focusing the threat over Montana. Tuesday: A shortwave ridge of high pressure will replace the trough over the Inland Northwest for Tuesday. Look for relatively light winds, clear skies and temperatures 5 to 8 degrees above average. /GKoch Tuesday night through Thursday evening...General long-wave trof lingers overhead but the air-mass contained in it is not very unstable and does not have much moisture tied to any discrete feature traversing through it. As thus for the most part a dry forecast remains, with exception being minimal chance for afternoon/evening mountain thunderstorms up North and over the Idaho Panhandle Thursday afternoon and evening. Forecast temperatures remain just slightly on the warm side of what would be considered normal for this time of year. Other shortwave features of note will be a dry disturbance passage on Wednesday afternoon and evening which will increase the wind some but only to low breezy category at most. /Pelatti Thursday night through Monday: The Inland Northwest remains in a more active pattern through the week`s end, before high pressure starts to nudge in Sunday and Monday. A shortwave system continues to slip through Idaho into Montana Thursday night, even as a second shortwave begins to move toward the Cascades. That second shortwave slips across eastern Washington and north Idaho through Friday, with a third wave slipping by Saturday before high pressure begins to nudge in Saturday night. Models continue to disagree over some of the details. Yet the progression of these features will bring some shower and thunderstorm chances to the region. The main chances remain around the northern mountains. Smaller chances will be found across the Blue Mountains through the Central Panhandle, including the Palouse as the wave is exiting Thursday night. While some of these waves are depicted as being somewhat dynamic/strong, models still do not depict significant instability and keep the deeper moisture southeast of the region. So regardless of timing and track, fuel for showers is not impressive. Thus over PoPs remain slight or isolated in nature. Look for occasional breezy conditions, especially Friday, with the passage of these waves. Although a couple models skim another wave by southern BC, near the WA/ID border early next week, drier conditions are forecast going into Sunday and Monday. Look for slightly cooler than normal conditions around the end of the work week, before temperatures warm closer to or slightly above seasonal norms going into early next week. /J. Cote` && .AVIATION... 18Z TAFS: Showers and thunderstorms will be the main aviation impact this afternoon. A weak surface pressure trough currently lays over the Spokane/Coeur D`Alene areas and should be the focus for afternoon convection. RUC analysis of surface based CAPE and convective inhibition compares favorably with the 12z NAM prog. It looks like the convective temperature will be reached around 20-21z. The window of opportunity for thunderstorms is relatively brief as the upper trough will shift into western Montana shortly after 00z putting the Idaho Panhandle and eastern Washington in a region of subsidence. Instability and shear are marginal for organized multicell thunderstorms. Hail up to dime size and gusts to 40 mph look to be the upper end of what we can expect with the strongest cells this afternoon. /GKoch && .PRELIMINARY POINT TEMPS/POPS... Spokane 58 89 60 89 59 83 / 0 0 0 0 0 10 Coeur d`Alene 56 87 58 87 58 83 / 10 0 0 0 0 10 Pullman 53 87 55 88 55 82 / 0 0 0 10 10 10 Lewiston 62 95 64 95 63 90 / 0 0 0 10 10 10 Colville 53 90 56 92 56 86 / 10 0 0 0 0 10 Sandpoint 50 85 53 86 54 82 / 20 0 0 0 0 10 Kellogg 54 87 57 87 58 82 / 10 0 0 0 10 10 Moses Lake 60 94 62 94 60 87 / 0 0 0 0 0 0 Wenatchee 64 92 65 91 62 85 / 0 0 0 0 0 0 Omak 60 94 60 92 59 86 / 0 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1140 AM PDT Mon Jul 8 2013 .SYNOPSIS... A weather system passing through the Inland Northwest today will promote scattered showers and thunderstorms across the northern mountains of Washington and Idaho, as well as southeast Washington. Tuesday and Wednesday will be the warmest days this week with high temperatures in the upper 80s to mid 90s. Thursday through the upcoming weekend will be occasionally breezy with temperatures pretty close to average. && .DISCUSSION... The morning forecast has been updated to remove showers and thunderstorms from southeast Washington and the Kamiah/Lewiston areas. The high-based activity that occurred early this morning over northeast Oregon and the southern Idaho Panhandle was driven by mid-level instability and warm advection processes, and has pushed east of the Spokane forecast area. Further north in the Bonners Ferry, Colville and Wilbur areas, clusters of showers and thunderstorms are occurring in the vicinity of a slow moving upper level trough. Look for these clusters to migrate eastward through the morning and afternoon. The 06z and 12z NAM suggest that thunderstorms may develop as far south as Spokane and far northern Whitman counties this afternoon. This idea is supported by the high resolution HRRR. This scenario makes sense given the presence of a weak surface trough currently located over Spokane, Latah and southern Shoshone counties. Some thunderstorms this afternoon will have the potential to produce brief heavy rain and possibly some hail. /GKoch && .AVIATION... 18Z TAFS: Showers and thunderstorms will be the main aviation impact this afternoon. A weak surface pressure trough currently lays over the Spokane/Coeur D`Alene areas and should be the focus for afternoon convection. RUC analysis of surface based CAPE and convective inhibition compares favorably with the 12z NAM prog. It looks like the convective temperature will be reached around 20-21z. The window of opportunity for thunderstorms is relatively brief as the upper trough will shift into western Montana shortly after 00z putting the Idaho Panhandle and eastern Washington in a region of subsidence. Instability and shear are marginal for organized multicell thunderstorms. Hail up to dime size and gusts to 40 mph look to be the upper end of what we can expect with the strongest cells this afternoon. /GKoch && .PRELIMINARY POINT TEMPS/POPS... Spokane 83 58 90 60 89 59 / 40 0 0 0 0 0 Coeur d`Alene 80 55 87 58 87 58 / 40 10 0 0 0 0 Pullman 82 52 88 55 88 55 / 10 0 0 0 10 10 Lewiston 90 61 96 64 95 63 / 10 0 0 0 10 10 Colville 84 52 92 56 92 56 / 60 10 0 0 0 0 Sandpoint 77 49 86 53 86 54 / 60 20 0 0 0 0 Kellogg 78 54 88 57 87 58 / 50 10 0 0 0 10 Moses Lake 91 59 94 62 94 60 / 0 0 0 0 0 0 Wenatchee 88 63 93 65 91 62 / 0 0 0 0 0 0 Omak 88 58 94 60 92 59 / 20 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
645 AM PDT Mon Jul 8 2013 .SYNOPSIS... A weather system passing through the Inland Northwest today will promote scattered showers and thunderstorms across the northern mountains of Washington and Idaho...as well as southeast Washington. Warm and dry conditions are expected around mid-week before a cold front knocks temperatures down closer to seasonal norms. Slight shower and thunderstorms chances will be common for all mountain zones. Otherwise expect dry and occasionally windy conditions Wednesday through Friday. && .DISCUSSION... Quick update for this morning: Two lines of elevated thunderstorms continue to impact the Inland NW this morning. One extends from NE Oregon through the Camas Prairie...western Nez Perce County...into Shoshone County. This line is showing signs of decreasing lightning activity and continues to slowly drift east, but generally slower then expected. The second line of storms has made very little eastward progress this morning and remains from Grand Coulee NE through extreme southeastern Okanogan...central Ferry...and northern Stevens/Pend Oreille Counties. This line continues to produce a decent amount of lightning...or 4-6 strikes every 5 minutes. The upper-level trof is now over the Cascades and should continue east and take this line with east over the next few hours. HRRR does indicate this activity will begin to wane over the next few hours. We have also increased Pops across NE WA and the Nrn ID Panhandle including the Spokane-CDA area. 06z NAM initialized the 12z sounding well and 06z GFS is quite unstable as well btwn 18-23z over these areas. Additionally, HRRR shows numerous storms firing around noon today and given the break in the action between the aforementioned ongoing lines of convection, we should warm sufficiently to achieve the convective temperature of 80F near 20z. Activity may fire quicker given the presence of lift along the approaching shortwave. GFS/NAM modeled CAPES range from 700-1100 J/kg. Shear is best now and will be decreasing below 30kts so there is a small window which both may be achieved, otherwise a modest CAPE and low shear profile could still support a few organized storms capable of small hail, gusty winds, heavy downpours, and frequent lightning. /sb && .AVIATION... 12Z TAFS: Two areas of elevated thunderstorm activity currently over the region...one over the northern mountains of WA and second frm KMLP to KPUW and points south. Expect this activity to persist through 13z vcnty KPUW/KLWS and 17z in extreme NE WA before shifting east into Nrn ID and Wrn MT. Following a few hours of heating btwn 15-19z...Sct -shra and -tsra are expected across a majority of NE WA and Nrn ID. This activity will wane arnd 00z in WA and 02Z in ID. A few storms will be capable of small hail, gusty winds, and heavy downpours. Drier conditions will be present near the Cascades today. High pressure will build in overnight delivering clearing skies, light winds, and drier conditions. /sb && .PRELIMINARY POINT TEMPS/POPS... Spokane 83 58 90 60 89 59 / 40 0 0 0 0 0 Coeur d`Alene 80 55 87 58 87 58 / 40 10 0 0 0 0 Pullman 82 52 88 55 88 55 / 30 0 0 0 10 10 Lewiston 90 61 96 64 95 63 / 60 0 0 0 10 10 Colville 84 52 92 56 92 56 / 70 10 0 0 0 0 Sandpoint 77 49 86 53 86 54 / 60 20 0 0 0 0 Kellogg 78 54 88 57 87 58 / 70 10 0 0 0 10 Moses Lake 91 59 94 62 94 60 / 0 0 0 0 0 0 Wenatchee 88 63 93 65 91 62 / 0 0 0 0 0 0 Omak 88 58 94 60 92 59 / 20 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
645 PM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 451 PM CDT TUE JUL 9 2013 DESPITE DECENT RECOVERY IN TEMPERATURES AFTER THE PASSAGE OF THE MORNING/MIDDAY CONVECTION...SUCH AS LA CROSSE CLIMBING UP TO 90F WITH A DEWPOINT OF 72F...CONVECTION IS DEFINITELY STRUGGLING. TWO THINGS ARE GOING ON HERE... 1. MASSIVE DRYING SEEN ON WATER VAPOR IN THE WAKE OF THE MORNING/MIDDAY CONVECTION AND ASSOCIATED MCV/SHORTWAVE TROUGH. THIS DRYING IMPLIES SUBSIDENCE. 2. A SURGE OF WARMER AIR AT 750MB ACCOMPANYING THE MASSIVE DRYING. THIS IS SEEN NICELY ON 20Z TAMDAR SOUNDINGS AT MPX AND DMX WHICH ARE 14C AND 16C RESPECTIVELY. THE LOWER TEMPERATURES AT MPX HAVE ALLOWED SOME CONVECTION TO FIRE NORTH OF LA CROSSE...HOWEVER...OVERALL THESE VALUES ARE PUTTING A CAP TO CONVECTION. MODIFYING A RAP SOUNDING AT 22Z FOR LA CROSSE WITH THE CURRENT SURFACE TEMP/DEWPOINTS AND A 16C 750MB TEMP STILL SHOWS A LITTLE CAPPING TO OVERCOME. ANTICIPATING LITTLE CHANGE IN CONVECTIVE ACTIVITY THROUGH THE NEXT COUPLE HOURS AS WE STAY IN THE SUBSIDENCE/DRYING ALOFT AND WARM 750MB AIR SPREADS EAST. ADDITIONALLY...WE WILL BE APPROACHING THE END OF HEATING SHORTLY...WHICH IN TURN WILL ONLY INCREASE THE CIN HEADING THROUGH THE EVENING. .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 250 PM CDT TUE JUL 9 2013 AN UPPER LEVEL SHORTWAVE TROUGH WAS TRACKING EAST ACROSS THE NORTHERN PLAINS THIS AFTERNOON...AND WILL WORK ACROSS NORTHERN PARTS OF THE REGION THIS EVENING. AHEAD OF THE UPPER LEVEL ENERGY AND AT THE SFC...AN ASSOCIATED FRONTAL BOUNDARY IS PROGGED TO MOVE OVER THE LOCAL FORECAST AREA BY 00Z...EXITING INTO EASTERN WI AFTER 06Z. MORNING/EARLY AFTERNOON CONVECTION HAS WORKED OVER THE ATMOSPHERE PRETTY GOOD...AND NOT A LOT OF TIME/SPACE TO RE-ESTABLISH SOME INSTABILTY AHEAD OF THE FRONT. MESO MODELS NOT BULLISH ON FIRING MUCH/IF ANY CONVECTION ALONG THE SFC BOUNDARY AS IT SWEEPS THROUGH THIS EVENING. THINK THIS IS THE WAY TO GO. THE CAVEAT...OF COURSE...IS IF THE ATMOSPHERE CAN JUICE BACK UP...THE STORM CHANCES WOULD INCREASE...AND THERE COULD BE A STRONG/SEVERE RISK. LATEST RADAR IMAGERY HAS SHOWN SOME DEVELOPMENT OVER NORTHWEST WI...ASSOCIATED WITH AN MCV FROM THE MORNING CONVECTION. NOT MUCH ELSEWHERE...ALTHOUGH SOME AGGRAVATED CU PER SATELLITE IMAGERY COULD EVENTUALLY BECOME SHOWERS/STORMS. WILL MONITOR TRENDS...BUT WILL STEER THE FORECAST FOR LESS PCPN CHANCES. HIGH PRESSURE STARTS TO BUILD IN FROM THE NORTHERN PLAINS ON WED...CLEARING OUT THE SKIES AND USHERING IN A MUCH COOLER AND DRIER AIRMASS. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 250 PM CDT TUE JUL 9 2013 HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE FOR THE REGION INTO FRIDAY...WITH RELATIVELY COOLER/LESS HUMID AIR FOR THE REST OF THE WORK WEEK. UPPER LEVEL SHORTWAVE TROUGH WILL DRIVE EASTWARD ACROSS SOUTHERN CANADA FOR THE UPCOMING WEEKEND. WHILE THE BULK OF THE UPPER LEVEL ENERGY WILL HOLD WELL NORTH OF THE LOCAL AREA...THIS SYSTEM WILL DRAG A SFC FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FRI NIGHT/SAT. THE GFS/ECMWF LAYS UP THE FRONT FROM WEST TO EAST AND HANGS IT ACROSS THE REGION INTO THE EARLY PART OF NEXT WEEK. GOOD LOW LEVEL MOISTURE RETURN INTO THE BOUNDARY WILL HELP FUEL SHOWERS/STORMS...WITH SOME INSTABILITY TO POWER STORMS. WIND SHEAR AT THIS TIME LOOKS MORE NORTH OF THE FRONT. THIS SCENARIO COULD BRING HEAVY RAINS TO PARTS OF THE REGION...WITH TRAINING STORMS AND A GOOD TAP INTO MOISTURE. THAT SAID...THERE IS UNCERTAINTY WITH WHERE THE FRONT WILL REST AND IF IT WAVERS NORTH-SOUTH. WILL STICK WITH A CONSENSUS/EC BLEND FOR THE RAIN CHANCES...FAVORING RAIN CHANCES TO THE NORTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 645 PM CDT TUE JUL 9 2013 A LOW PRESSURE TROUGH WENT THROUGH THE TAF SITES DURING THE AFTERNOON. IN ITS WAKE...WEST TO NORTHWEST WINDS ARE BRINGING DRIER AIR INTO THE TAF SITES. THIS DRY AIR WILL KEEP CONDITIONS VFR THROUGH WEDNESDAY...AIDED TOO BY HIGH PRESSURE BUILDING TOWARDS THE TAF SITES FROM THE DAKOTAS. A FAIRLY TIGHT PRESSURE GRADIENT IS EXPECTED TO MAINTAIN AN 8-12 KT WIND MUCH OF THE NIGHT. DAYTIME MIXING ON WEDNESDAY WILL ALLOW THE WINDS TO GUST UP TO 18 KT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1225 PM CDT MON JUL 8 2013 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 353 AM CDT MON JUL 8 2013 WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWING A MID-LEVEL SHORTWAVE TROUGH EXTENDING FROM WESTERN LAKE SUPERIOR THROUGH APPROXIMATELY SIOUX FALLS SD. PUSH OF 850MB MOIST TRANSPORT AND A CONVERGENCE/WINDSHIFT LINE AT THE SURFACE WAS SUPPORTING A BROKEN BAND OF SHOWERS AND THUNDERSTORMS EXTENDING FROM NORTHERN WI THROUGH EASTERN IA/WESTERN IL. MODELS SHOW THIS MID-LEVEL TROUGH AND SURFACE CONVERGENCE/WINDSHIFT LINE MOVING EAST AND SOUTHEAST OF THE AREA THIS MORNING ALONG WITH ANY 850MB MOISTURE TRANSPORT. THIS WILL BRING AN END TO THE SHOWER/THUNDER CHANCES TODAY AS MID-LEVEL RIDGING BUILDS IN BEHIND THIS DEPARTING WAVE. THERE LOOKS TO BE A CHANCE OF CONVECTION REDEVELOPING ALONG THIS SURFACE BOUNDARY JUST TO OUR SOUTH...BUT BELIEVE THIS ACTION WILL REMAIN OUT OF OUR AREA. OTHERWISE...LOOK FOR ANOTHER VERY WARM AND MUGGY DAY WITH HIGHS IN THE 80S...WITH PERHAPS A FEW SPOTS ACROSS FAR SOUTHWEST WI/NORTHEAST IA POKING AT THE 90 DEGREE MARK. WITH DEW POINTS SITTING IN THE LOWER 70S...PLAN ON HEAT INDICES IN THE MID 90S ALONG AND SOUTH OF THE I-94 CORRIDOR...WITH A FEW SPOTS IN THE 95 TO 100 DEGREE RANGE ACROSS NORTHEAST IA. FOCUS THEN SHIFTS TO MCS LIKELY DEVELOPING OVER SOUTH DAKOTA THIS EVENING IN RESPONSE TO INCREASING LOW LEVEL JET/850MB MOISTURE TRANSPORT AHEAD OF A SW U.S. MONSOONAL MID-LEVEL TROUGH AND LOW PRESSURE OVER THE ROCKY MOUNTAIN FRONT OF WY. GFS/NAM IN FAIRLY GOOD AGREEMENT THAT THIS MCS WILL PROPAGATE EASTWARD ACROSS SOUTHERN MN AFTER MIDNIGHT. TRENDED POPS TOWARD THIS SOLUTION WITH BULK OF SHOWER/THUNDER CHANCES STAYING WEST OF THE MISSISSIPPI THROUGH 12Z MONDAY. MODELS THEN DIVERGE A BIT TUESDAY ON THE PATH OF THE MCS. THE GFS WANTS TO TAKE IT ALONG AND NORTH OF THE I-94 CORRIDOR WHEREAS THE NAM TAKES IT MORE ACROSS THE I-90 CORRIDOR. ONE THING IS FOR SURE...THE MODELS HAVE BEEN VERY CONSISTENT WITH THIS MCS SIGNATURE. AND...WITH HIGHER-END PRECIPITABLE WATER VALUES IN THE 2-2.5 INCH RANGE WHICH IS SOME 200 PERCENT ABOVE NORMAL...VERY HEAVY RAINFALL WILL BE A REAL THREAT FOR SOMEWHERE IN OUR AREA. USED A BLEND APPROACH FOR NOW...WHICH WOULD PUT THE HIGHEST LIKELIHOOD OF HEAVIEST RAINFALL ALONG/NORTH OF THE I-90 CORRIDOR. SEE HYDROLOGY SECTION BELOW FOR EXPECTED IMPACT OF THIS HEAVY RAIN. OTHERWISE...LOOKS LIKE IF THE MCS/DEBRIS CLOUDS CLEAR THE AREA BY LATER IN THE AFTERNOON...SEVERE THUNDERSTORMS COULD ERUPT AS A RATHER VIGOROUS MID-LEVEL TROUGH DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS AND PUSHES A COLD FRONT INTO THE REGION. NAM/GFS SHOW THE POTENTIAL FOR 0-1ML MUCAPE TO BUILD INTO THE 3500-5500J/KG RANGE BY LATE AFTERNOON WITH AMPLE 0-3KM BULK SHEAR IN THE 30-50KT RANGE. THIS COULD LEAD TO EXPLOSIVE DEEP CONVECTION MAINLY SOUTH OF THE I-90 CORRIDOR. DAMAGING WIND/LARGE HAIL/LOCALIZED FLASH FLOODING/ ISOLATED TORNADO ALL A THREAT. LINGERING SHOWER/THUNDERSTORM CHANCES WILL EXIST GOING INTO TUESDAY NIGHT IN ASSOCIATION WITH THE MID-LEVEL TROUGH DROPPING SOUTHEAST THROUGH THE AREA. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 353 AM CDT MON JUL 8 2013 DRIER/COOLER WEATHER EXPECTED WEDNESDAY THROUGH THURSDAY AS HIGH PRESSURE DROPS IN FROM THE NORTHERN PLAINS. LOOK FOR HIGHS IN THE 76-81 DEGREE RANGE WEDNESDAY AND 78-82 ON THURSDAY...WITH DEW POINTS IN THE MID-UPPER 50S. MID-UPPER LEVEL RIDGING/INCREASING SOUTHERLY FLOW BRINGS WARMING AND HIGHER HUMIDITY LEVELS BACK INTO THE AREA FRIDAY AND SATURDAY. WILL HAVE TO WATCH FRIDAY NIGHT THROUGH SUNDAY FOR A CHANCE OF SHOWERS AND THUNDERSTORMS AS THE EC/GFS SHOW A MID-LEVEL TROUGH/WEAK COLD FRONT TOPPING THE RIDGE AND TOWARD THE AREA. OTHERWISE...LOOK FOR HIGHS IN THE LOWER 80S FRIDAY AND SATURDAY THEN LOWERING SOME BACK INTO THE UPPER 70S/AROUND 80 ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1225 PM CDT MON JUL 8 2013 MVFR/IFR CIGS/VSBYS CONTINUED TO ERODE/IMPROVE WITH DIURNAL WARMING/ MIXING THRU THE MID-LATE MORNING HOURS. THESE CLOUDS DECKS WILL CONTINUE TO ERODE THRU THE EARLY AFTERNOON HOURS AS WELL AS IMPROVING VSBYS AS WEAK NORTHWEST FLOW BEHIND A COOL FRONT SPREADS SOME SLIGHTLY DRIER AIR INTO THE AREA. VFR CONDITIONS EXPECTED FOR THE MID AFTERNOON THRU EVENING HOURS. WITH THE MOIST LOW LEVEL AIRMASS OVER THE AREA...LIGHT WINDS AND PARTLY CLOUDY SKIES THIS EVENING...MVFR VSBYS IN BR EXPECTED AFTER MIDNIGHT. MOISTURE/FORCING/LIFT START TO RETURN AFTER MIDNIGHT...WITH AN UNSTABLE AND VERY MOIST AIRMASS BEING LIFTED NORTH/EAST OVER THE FRONTAL BOUNDARY RETURNING NORTH AS A WARM FRONT. TREND HAS BEEN SLIGHTLY SLOW WITH THE WARM FRONT...FORCING AND MOISTURE LIFTING NORTHEAST...NOW LOOKING TO IMPACT THE TAF SITES MORE ON TUESDAY INTO TUE NIGHT. ONCE THE FORCING/MOISTURE ARRIVE...A BROAD BAND OF SHRA/TSRA IS EXPECTED TO LIFT NORTHEAST ACROSS THE TAF SITES. SPREAD VCTS/CB AND MVFR CIGS INTO THE TAF SITE IN THE 09-11Z TIME-FRAME THEN PREVAILED -SHRA AND VCTS/CB AFTER 11-13Z. THERE MAY BE A BREAK DURING THE LATE MORNING/ EARLY AFTERNOON HOURS...WITH A COLD FRONT LOOKING TO BRING MORE SHRA/TSRA TO THE AREA FOR THE LATER AFTERNOON AND EVENING HOURS OF TUESDAY. && .HYDROLOGY...(TUESDAY) ISSUED AT 353 AM CDT MON JUL 8 2013 SIGNAL REMAINS HIGH FOR A COMPLEX OF THUNDERSTORMS TO ROLL THROUGH THE AREA TUESDAY. CONFIDENCE IS INCREASING THAT THIS COMPLEX WILL MOVE THROUGH THE AREA SOMEWHERE IN THE 7 AM TO NOON TIME FRAME...THEN MOVE EAST OF THE AREA AFTER THAT. HOWEVER...CONFIDENCE IS LOWER WITH EXACT TRACK OF THE COMPLEX OF STORMS. RIGHT NOW...THE HIGHEST POTENTIAL FOR HEAVIER RAINFALL LOOKS TO BE ALONG AND NORTH OF THE I-90 CORRIDOR. WITH PRECIPITABLE WATER VALUES IN THE 2-2.5 INCH RANGE WHICH IS SOME 200 PERCENT ABOVE NORMAL...LOOK FOR THE POTENTIAL OF VERY HEAVY RAINFALL WITH THIS COMPLEX OF STORMS. TWO POSITIVE FACTORS TO LOOK AT. 1. THE COMPLEX WILL BE TRANSITORY IN NATURE AND 2. 6-HOUR FLASH FLOOD GUIDANCE IS IN THE 3-5 INCH RANGE. HOWEVER...IF DOWNPOURS ARE TORRENTIAL ENOUGH...LITTLE WILL BE ABSORBED IMMEDIATELY IN THE GROUND AND COULD CAUSE SOME LOCALIZED PONDING IN POUR DRAINAGE AREAS AND RUNOFF INTO AREA RIVERS. THIS WILL LIKELY CAUSE SOME WITHIN BANK RISES...BUT NOT CONFIDENT ON ANY WIDESPREAD FLOODING AT THIS POINT. AS A COLD FRONT DROPS THROUGH THE AREA TUESDAY AFTERNOON...ANOTHER BATCH OF HEAVIER RAINFALL COULD FALL. THIS AGAIN SHOULD BE TRANSITORY IN NATURE...BUT COULD CAUSE SOME LOCALIZED PONDING/RUNOFF OF WATER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION.....RRS HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
607 AM CDT MON JUL 8 2013 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 353 AM CDT MON JUL 8 2013 WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWING A MID-LEVEL SHORTWAVE TROUGH EXTENDING FROM WESTERN LAKE SUPERIOR THROUGH APPROXIMATELY SIOUX FALLS SD. PUSH OF 850MB MOIST TRANSPORT AND A CONVERGENCE/WINDSHIFT LINE AT THE SURFACE WAS SUPPORTING A BROKEN BAND OF SHOWERS AND THUNDERSTORMS EXTENDING FROM NORTHERN WI THROUGH EASTERN IA/WESTERN IL. MODELS SHOW THIS MID-LEVEL TROUGH AND SURFACE CONVERGENCE/WINDSHIFT LINE MOVING EAST AND SOUTHEAST OF THE AREA THIS MORNING ALONG WITH ANY 850MB MOISTURE TRANSPORT. THIS WILL BRING AN END TO THE SHOWER/THUNDER CHANCES TODAY AS MID-LEVEL RIDGING BUILDS IN BEHIND THIS DEPARTING WAVE. THERE LOOKS TO BE A CHANCE OF CONVECTION REDEVELOPING ALONG THIS SURFACE BOUNDARY JUST TO OUR SOUTH...BUT BELIEVE THIS ACTION WILL REMAIN OUT OF OUR AREA. OTHERWISE...LOOK FOR ANOTHER VERY WARM AND MUGGY DAY WITH HIGHS IN THE 80S...WITH PERHAPS A FEW SPOTS ACROSS FAR SOUTHWEST WI/NORTHEAST IA POKING AT THE 90 DEGREE MARK. WITH DEW POINTS SITTING IN THE LOWER 70S...PLAN ON HEAT INDICES IN THE MID 90S ALONG AND SOUTH OF THE I-94 CORRIDOR...WITH A FEW SPOTS IN THE 95 TO 100 DEGREE RANGE ACROSS NORTHEAST IA. FOCUS THEN SHIFTS TO MCS LIKELY DEVELOPING OVER SOUTH DAKOTA THIS EVENING IN RESPONSE TO INCREASING LOW LEVEL JET/850MB MOISTURE TRANSPORT AHEAD OF A SW U.S. MONSOONAL MID-LEVEL TROUGH AND LOW PRESSURE OVER THE ROCKY MOUNTAIN FRONT OF WY. GFS/NAM IN FAIRLY GOOD AGREEMENT THAT THIS MCS WILL PROPAGATE EASTWARD ACROSS SOUTHERN MN AFTER MIDNIGHT. TRENDED POPS TOWARD THIS SOLUTION WITH BULK OF SHOWER/THUNDER CHANCES STAYING WEST OF THE MISSISSIPPI THROUGH 12Z MONDAY. MODELS THEN DIVERGE A BIT TUESDAY ON THE PATH OF THE MCS. THE GFS WANTS TO TAKE IT ALONG AND NORTH OF THE I-94 CORRIDOR WHEREAS THE NAM TAKES IT MORE ACROSS THE I-90 CORRIDOR. ONE THING IS FOR SURE...THE MODELS HAVE BEEN VERY CONSISTENT WITH THIS MCS SIGNATURE. AND...WITH HIGHER-END PRECIPITABLE WATER VALUES IN THE 2-2.5 INCH RANGE WHICH IS SOME 200 PERCENT ABOVE NORMAL...VERY HEAVY RAINFALL WILL BE A REAL THREAT FOR SOMEWHERE IN OUR AREA. USED A BLEND APPROACH FOR NOW...WHICH WOULD PUT THE HIGHEST LIKELIHOOD OF HEAVIEST RAINFALL ALONG/NORTH OF THE I-90 CORRIDOR. SEE HYDROLOGY SECTION BELOW FOR EXPECTED IMPACT OF THIS HEAVY RAIN. OTHERWISE...LOOKS LIKE IF THE MCS/DEBRIS CLOUDS CLEAR THE AREA BY LATER IN THE AFTERNOON...SEVERE THUNDERSTORMS COULD ERUPT AS A RATHER VIGOROUS MID-LEVEL TROUGH DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS AND PUSHES A COLD FRONT INTO THE REGION. NAM/GFS SHOW THE POTENTIAL FOR 0-1ML MUCAPE TO BUILD INTO THE 3500-5500J/KG RANGE BY LATE AFTERNOON WITH AMPLE 0-3KM BULK SHEAR IN THE 30-50KT RANGE. THIS COULD LEAD TO EXPLOSIVE DEEP CONVECTION MAINLY SOUTH OF THE I-90 CORRIDOR. DAMAGING WIND/LARGE HAIL/LOCALIZED FLASH FLOODING/ ISOLATED TORNADO ALL A THREAT. LINGERING SHOWER/THUNDERSTORM CHANCES WILL EXIST GOING INTO TUESDAY NIGHT IN ASSOCIATION WITH THE MID-LEVEL TROUGH DROPPING SOUTHEAST THROUGH THE AREA. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 353 AM CDT MON JUL 8 2013 DRIER/COOLER WEATHER EXPECTED WEDNESDAY THROUGH THURSDAY AS HIGH PRESSURE DROPS IN FROM THE NORTHERN PLAINS. LOOK FOR HIGHS IN THE 76-81 DEGREE RANGE WEDNESDAY AND 78-82 ON THURSDAY...WITH DEW POINTS IN THE MID-UPPER 50S. MID-UPPER LEVEL RIDGING/INCREASING SOUTHERLY FLOW BRINGS WARMING AND HIGHER HUMIDITY LEVELS BACK INTO THE AREA FRIDAY AND SATURDAY. WILL HAVE TO WATCH FRIDAY NIGHT THROUGH SUNDAY FOR A CHANCE OF SHOWERS AND THUNDERSTORMS AS THE EC/GFS SHOW A MID-LEVEL TROUGH/WEAK COLD FRONT TOPPING THE RIDGE AND TOWARD THE AREA. OTHERWISE...LOOK FOR HIGHS IN THE LOWER 80S FRIDAY AND SATURDAY THEN LOWERING SOME BACK INTO THE UPPER 70S/AROUND 80 ON SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 607 AM CDT MON JUL 8 2013 A WEAK COLD FRONT IS PROGRESSING SOUTHEAST ACROSS THE AREA THIS MORNING. THE WINDS HAVE ALREADY SWUNG AROUND TO THE NORTHWEST BEHIND THE FRONT AT KRST AND EXPECT THAT THEY WILL DO THE SAME AT KLSE BY MID MORNING. IR SATELLITE THIS MORNING SHOWS LITTLE IN THE WAY OF CLOUD COVER ALONG AND BEHIND THE WEAK FRONT AND THE 08.06Z NAM BUFKIT SOUNDINGS INDICATE IT SHOULD STAY THAT WAY FOR MUCH OF THE DAY. FOCUS THEN TURNS TO THE THUNDERSTORM CHANCES FOR THE OVERNIGHT HOURS. THE FRONT WILL START TO RETURN BACK TO THE NORTH AS A WARM FRONT AS A SHORT WAVE TROUGH CURRENTLY OVER WYOMING MOVES INTO THE AREA. THUNDERSTORMS WITH THIS FEATURE ARE EXPECTED TO DEVELOP ACROSS SOUTH DAKOTA THIS AFTERNOON AND THEN TRACK EAST ALONG AND NORTH OF THE WARM FRONT THROUGH THE OVERNIGHT. CURRENT EXPECTATIONS ARE THAT THESE STORMS WILL IMPACT BOTH TAF SITES BUT NOT UNTIL LATE IN THE FORECAST PERIOD SO WILL JUST SHOW A VCTS WITH VFR CONDITIONS. WOULD EXPECT THE STORMS TO HAVE THE POTENTIAL TO PRODUCE MVFR CONDITIONS IF THE HEAVIEST RAINFALL CAN COME ACROSS THE AIRPORTS. && .HYDROLOGY...(TUESDAY) ISSUED AT 353 AM CDT MON JUL 8 2013 SIGNAL REMAINS HIGH FOR A COMPLEX OF THUNDERSTORMS TO ROLL THROUGH THE AREA TUESDAY. CONFIDENCE IS INCREASING THAT THIS COMPLEX WILL MOVE THROUGH THE AREA SOMEWHERE IN THE 7 AM TO NOON TIME FRAME...THEN MOVE EAST OF THE AREA AFTER THAT. HOWEVER...CONFIDENCE IS LOWER WITH EXACT TRACK OF THE COMPLEX OF STORMS. RIGHT NOW...THE HIGHEST POTENTIAL FOR HEAVIER RAINFALL LOOKS TO BE ALONG AND NORTH OF THE I-90 CORRIDOR. WITH PRECIPITABLE WATER VALUES IN THE 2-2.5 INCH RANGE WHICH IS SOME 200 PERCENT ABOVE NORMAL...LOOK FOR THE POTENTIAL OF VERY HEAVY RAINFALL WITH THIS COMPLEX OF STORMS. TWO POSITIVE FACTORS TO LOOK AT. 1. THE COMPLEX WILL BE TRANSITORY IN NATURE AND 2. 6-HOUR FLASH FLOOD GUIDANCE IS IN THE 3-5 INCH RANGE. HOWEVER...IF DOWNPOURS ARE TORRENTIAL ENOUGH...LITTLE WILL BE ABSORBED IMMEDIATELY IN THE GROUND AND COULD CAUSE SOME LOCALIZED PONDING IN POUR DRAINAGE AREAS AND RUNOFF INTO AREA RIVERS. THIS WILL LIKELY CAUSE SOME WITHIN BANK RISES...BUT NOT CONFIDENT ON ANY WIDESPREAD FLOODING AT THIS POINT. AS A COLD FRONT DROPS THROUGH THE AREA TUESDAY AFTERNOON...ANOTHER BATCH OF HEAVIER RAINFALL COULD FALL. THIS AGAIN SHOULD BE TRANSITORY IN NATURE...BUT COULD CAUSE SOME LOCALIZED PONDING/RUNOFF OF WATER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04 HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
353 AM CDT MON JUL 8 2013 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 353 AM CDT MON JUL 8 2013 WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWING A MID-LEVEL SHORTWAVE TROUGH EXTENDING FROM WESTERN LAKE SUPERIOR THROUGH APPROXIMATELY SIOUX FALLS SD. PUSH OF 850MB MOIST TRANSPORT AND A CONVERGENCE/WINDSHIFT LINE AT THE SURFACE WAS SUPPORTING A BROKEN BAND OF SHOWERS AND THUNDERSTORMS EXTENDING FROM NORTHERN WI THROUGH EASTERN IA/WESTERN IL. MODELS SHOW THIS MID-LEVEL TROUGH AND SURFACE CONVERGENCE/WINDSHIFT LINE MOVING EAST AND SOUTHEAST OF THE AREA THIS MORNING ALONG WITH ANY 850MB MOISTURE TRANSPORT. THIS WILL BRING AN END TO THE SHOWER/THUNDER CHANCES TODAY AS MID-LEVEL RIDGING BUILDS IN BEHIND THIS DEPARTING WAVE. THERE LOOKS TO BE A CHANCE OF CONVECTION REDEVELOPING ALONG THIS SURFACE BOUNDARY JUST TO OUR SOUTH...BUT BELIEVE THIS ACTION WILL REMAIN OUT OF OUR AREA. OTHERWISE...LOOK FOR ANOTHER VERY WARM AND MUGGY DAY WITH HIGHS IN THE 80S...WITH PERHAPS A FEW SPOTS ACROSS FAR SOUTHWEST WI/NORTHEAST IA POKING AT THE 90 DEGREE MARK. WITH DEW POINTS SITTING IN THE LOWER 70S...PLAN ON HEAT INDICES IN THE MID 90S ALONG AND SOUTH OF THE I-94 CORRIDOR...WITH A FEW SPOTS IN THE 95 TO 100 DEGREE RANGE ACROSS NORTHEAST IA. FOCUS THEN SHIFTS TO MCS LIKELY DEVELOPING OVER SOUTH DAKOTA THIS EVENING IN RESPONSE TO INCREASING LOW LEVEL JET/850MB MOISTURE TRANSPORT AHEAD OF A SW U.S. MONSOONAL MID-LEVEL TROUGH AND LOW PRESSURE OVER THE ROCKY MOUNTAIN FRONT OF WY. GFS/NAM IN FAIRLY GOOD AGREEMENT THAT THIS MCS WILL PROPAGATE EASTWARD ACROSS SOUTHERN MN AFTER MIDNIGHT. TRENDED POPS TOWARD THIS SOLUTION WITH BULK OF SHOWER/THUNDER CHANCES STAYING WEST OF THE MISSISSIPPI THROUGH 12Z MONDAY. MODELS THEN DIVERGE A BIT TUESDAY ON THE PATH OF THE MCS. THE GFS WANTS TO TAKE IT ALONG AND NORTH OF THE I-94 CORRIDOR WHEREAS THE NAM TAKES IT MORE ACROSS THE I-90 CORRIDOR. ONE THING IS FOR SURE...THE MODELS HAVE BEEN VERY CONSISTENT WITH THIS MCS SIGNATURE. AND...WITH HIGHER-END PRECIPITABLE WATER VALUES IN THE 2-2.5 INCH RANGE WHICH IS SOME 200 PERCENT ABOVE NORMAL...VERY HEAVY RAINFALL WILL BE A REAL THREAT FOR SOMEWHERE IN OUR AREA. USED A BLEND APPROACH FOR NOW...WHICH WOULD PUT THE HIGHEST LIKELIHOOD OF HEAVIEST RAINFALL ALONG/NORTH OF THE I-90 CORRIDOR. SEE HYDROLOGY SECTION BELOW FOR EXPECTED IMPACT OF THIS HEAVY RAIN. OTHERWISE...LOOKS LIKE IF THE MCS/DEBRIS CLOUDS CLEAR THE AREA BY LATER IN THE AFTERNOON...SEVERE THUNDERSTORMS COULD ERUPT AS A RATHER VIGOROUS MID-LEVEL TROUGH DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS AND PUSHES A COLD FRONT INTO THE REGION. NAM/GFS SHOW THE POTENTIAL FOR 0-1ML MUCAPE TO BUILD INTO THE 3500-5500J/KG RANGE BY LATE AFTERNOON WITH AMPLE 0-3KM BULK SHEAR IN THE 30-50KT RANGE. THIS COULD LEAD TO EXPLOSIVE DEEP CONVECTION MAINLY SOUTH OF THE I-90 CORRIDOR. DAMAGING WIND/LARGE HAIL/LOCALIZED FLASH FLOODING/ ISOLATED TORNADO ALL A THREAT. LINGERING SHOWER/THUNDERSTORM CHANCES WILL EXIST GOING INTO TUESDAY NIGHT IN ASSOCIATION WITH THE MID-LEVEL TROUGH DROPPING SOUTHEAST THROUGH THE AREA. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 353 AM CDT MON JUL 8 2013 DRIER/COOLER WEATHER EXPECTED WEDNESDAY THROUGH THURSDAY AS HIGH PRESSURE DROPS IN FROM THE NORTHERN PLAINS. LOOK FOR HIGHS IN THE 76-81 DEGREE RANGE WEDNESDAY AND 78-82 ON THURSDAY...WITH DEW POINTS IN THE MID-UPPER 50S. MID-UPPER LEVEL RIDGING/INCREASING SOUTHERLY FLOW BRINGS WARMING AND HIGHER HUMIDITY LEVELS BACK INTO THE AREA FRIDAY AND SATURDAY. WILL HAVE TO WATCH FRIDAY NIGHT THROUGH SUNDAY FOR A CHANCE OF SHOWERS AND THUNDERSTORMS AS THE EC/GFS SHOW A MID-LEVEL TROUGH/WEAK COLD FRONT TOPPING THE RIDGE AND TOWARD THE AREA. OTHERWISE...LOOK FOR HIGHS IN THE LOWER 80S FRIDAY AND SATURDAY THEN LOWERING SOME BACK INTO THE UPPER 70S/AROUND 80 ON SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1122 PM CDT SUN JUL 7 2013 A TROUGH OF LOW PRESSURE AT 05Z STRETCHED FROM OMAHA TO ROCHESTER AND EAU CLAIRE...DROPPING SOUTHEAST WITH TIME. SOME SHOWERS ALONG THIS TROUGH WERE IMPACTING RST...BUT THE END WAS RAPIDLY APPROACHING SUCH THAT THE 06Z TAF STARTS OFF DRY. SHOWERS APPEAR THAT THEY WILL MISS LSE...BUT COULD FORM NEARBY SO PUT A VCSH IN THE TAF THERE BETWEEN 06-09Z. HIGH PRESSURE THEN BUILDS IN BEHIND THE TROUGH FOR MONDAY...BRINGING WITH IT CLEARING SKIES AND DRIER AIR. REGARDING FOG POTENTIAL IN THE WAKE OF THE TROUGH FOR LATE TONIGHT...GIVEN LITTLE IF ANY PRECIPITATION OCCURRING AND POTENTIAL FOR CLOUDS AROUND TO KEEP TEMPERATURE/DEWPOINT SPREADS HIGH...CONCERN FOR FOG IS LOW. RAISED VISIBILITIES UP TO VFR FOR THAT 09-13Z TIME PERIOD. WINDS DURING THE NEXT 24 HOURS LOOK QUITE LIGHT...GENERALLY 5 KT OR LESS....WITH A WEAK PRESSURE GRADIENT IN PLACE. HEADING INTO MONDAY NIGHT...PARTICULARLY AFTER 06Z...THE TROUGH OF LOW PRESSURE LOOKS TO MARCH BACK NORTH AS A WARM FRONT TOWARDS THE TAF SITES. WILL NEED TO WATCH POTENTIAL FOR SHOWERS AND THUNDERSTORMS LATE IN THE NIGHT OR PERHAPS TUESDAY MORNING. && .HYDROLOGY...(TUESDAY) ISSUED AT 353 AM CDT MON JUL 8 2013 SIGNAL REMAINS HIGH FOR A COMPLEX OF THUNDERSTORMS TO ROLL THROUGH THE AREA TUESDAY. CONFIDENCE IS INCREASING THAT THIS COMPLEX WILL MOVE THROUGH THE AREA SOMEWHERE IN THE 7 AM TO NOON TIME FRAME...THEN MOVE EAST OF THE AREA AFTER THAT. HOWEVER...CONFIDENCE IS LOWER WITH EXACT TRACK OF THE COMPLEX OF STORMS. RIGHT NOW...THE HIGHEST POTENTIAL FOR HEAVIER RAINFALL LOOKS TO BE ALONG AND NORTH OF THE I-90 CORRIDOR. WITH PRECIPITABLE WATER VALUES IN THE 2-2.5 INCH RANGE WHICH IS SOME 200 PERCENT ABOVE NORMAL...LOOK FOR THE POTENTIAL OF VERY HEAVY RAINFALL WITH THIS COMPLEX OF STORMS. TWO POSITIVE FACTORS TO LOOK AT. 1. THE COMPLEX WILL BE TRANSITORY IN NATURE AND 2. 6-HOUR FLASH FLOOD GUIDANCE IS IN THE 3-5 INCH RANGE. HOWEVER...IF DOWNPOURS ARE TORRENTIAL ENOUGH...LITTLE WILL BE ABSORBED IMMEDIATELY IN THE GROUND AND COULD CAUSE SOME LOCALIZED PONDING IN POUR DRAINAGE AREAS AND RUNOFF INTO AREA RIVERS. THIS WILL LIKELY CAUSE SOME WITHIN BANK RISES...BUT NOT CONFIDENT ON ANY WIDESPREAD FLOODING AT THIS POINT. AS A COLD FRONT DROPS THROUGH THE AREA TUESDAY AFTERNOON...ANOTHER BATCH OF HEAVIER RAINFALL COULD FALL. THIS AGAIN SHOULD BE TRANSITORY IN NATURE...BUT COULD CAUSE SOME LOCALIZED PONDING/RUNOFF OF WATER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...AJ HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1123 PM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 949 PM CDT SUN JUL 7 2013 FORECAST STILL REMAINS PROBLEMATIC FOR TONIGHT. CONVECTION THAT WENT UP ALONG THE SURFACE TROUGH CONTINUES TO PUSH TOWARDS THE FORECAST AREA...IN PARTICULAR SOUTHEAST MINNESOTA. THIS IS DESPITE MLCAPE VALUES THAT HAVE DROPPED TO 500-1000 J/KG AND MLCIN THAT HAVE CLIMBED TO 100-150 J/KG. THE IMPACT OF THESE TWO VARIABLES HAS DEFINITELY KNOCKED DOWN THE AMOUNT OF LIGHTNING...AND IT APPEARS OUTFLOWS COMBINING WITH THE SURFACE TROUGH ARE WHAT IS HELPING TO KEEP SOME SHOWER ACTIVITY GOING. NOT SURE IF THE SHOWERS WILL LAST MORE THAN A FEW MORE HOURS...THOUGH...SINCE EACH PASSING HOUR WILL MEAN LESS CAPE AND MORE CIN. JUST TO OUR NORTH OVER NORTHERN WISCONSIN...NUMEROUS SHOWERS AND SOME THUNDERSTORMS HAVE DEVELOPED THERE. THESE ARE ON THE NOSE OF AN 850MB MOISTURE TRANSPORT CORE. THIS CORE LIFTS UP TOWARDS UPPER MICHIGAN IN THE NEXT FEW HOURS...SO THINKING MUCH OF THE CONVECTION MAY DO THE SAME...KEEPING TAYLOR/CLARK COUNTIES OUT OF MUCH SHOWER ACTIVITY. OVERNIGHT...LATEST 08.01Z RAP HAS ANOTHER 850MB MOISTURE TRANSPORT SURGE COMING UP OUT OF CENTRAL IOWA...IGNITING CONVECTION BY 07Z JUST EAST OF THE MS RIVER. HAVE LEFT THE 20-30 PERCENT CHANCES GOING OVERNIGHT FOR THIS SCENARIO. CONFIDENCE IS STILL LOW ON WHAT WILL HAPPEN OVERNIGHT...ESPECIALLY BECAUSE THE OVERALL LOW TO MID LEVEL MOISTURE TRANSPORT IS VEERING MORE EASTERLY IN RESPONSE TO THE 500MB FLOW TURNING ZONAL...AS WELL AS THAT SURFACE TROUGH MOVING INTO THE FORECAST AREA. UPDATE ISSUED AT 650 PM CDT SUN JUL 7 2013 CONVECTIVE THOUGHTS FOR TONIGHT... AT 2330Z...CLUSTER OF UNORGANIZED SHOWERS AND THUNDERSTORMS CONTINUES JUST NORTH AND WEST OF MINNEAPOLIS. THESE ARE ALONG A LOW PRESSURE TROUGH STRETCHING FROM NORTHWEST WISCONSIN INTO SOUTHWEST MN. TEMPERATURES IN THE UPPER 80S COMBINED WITH DEWPOINTS POOLING TO NEAR 70F ALONG THE TROUGH RESULTING IN MLCAPES 2000-2500 J/KG AND NO MLCIN. LACK OF 0-6 KM SHEAR HAS KEPT THESE UNORGANIZED...WITH OUTFLOWS OCCASIONALLY POPPING UP STORMS. TO THE WEST...ANOTHER CLUSTER OF SHOWERS AND THUNDERSTORMS BUT MUCH MORE ORGANIZED HAS BEEN PROGRESSING ACROSS EASTERN SOUTH DAKOTA. 0-6KM SHEAR THERE IS AROUND 40 KT...COMPARED TO LESS THAN 30 OVER CENTRAL MN. THE STORMS IN SOUTH DAKOTA ARE TAKING ON A SOUTH/SOUTHEASTWARD MOTION...THOUGH...INTO THE HIGHER INSTABILITY PRESENT IN EASTERN NEBRASKA WHERE UPWARDS OF 3500 J/KG OF MLCAPE IS SUGGESTED BY THE RAP. THE FORECAST TONIGHT IS VERY UNCERTAIN FOR PRECIPITATION BEING OBSERVED OVER THE FORECAST AREA. STORMS OVER CENTRAL MINNESOTA ARE SURFACE BASED INITIATED FROM DAYTIME HEATING...THUS ONCE TEMPERATURES BEGIN TO COOL...THEY SHOULD ALL DIMINISH DURING THE EVENING HOURS...PERHAPS BY 10 PM. ADDITIONALLY...RAP MLCAPE ANALYSIS SHOWS AN AREA OF 50 TO 200 MLCIN ALREADY PRESENT FROM NORTHEAST IOWA INTO SOUTHEAST MN...PROVIDING PROTECTION FROM STORMS MOVING IN THERE. NOW SOME SURFACE BASED STORMS COULD GO UP IN THE NEXT HOUR OR SO UP IN TAYLOR/CLARK COUNTIES IF THE LOW PRESSURE TROUGH CAN SINK SOUTH INTO THAT AREA. TO THE WEST...THERE WAS CONCERN FROM THE PREVIOUS FORECAST THE STORMS OVER SOUTH DAKOTA COULD TRACK EAST INTO OUR AREA. HOWEVER...THESE AS NOTED EARLIER ARE DROPPING MORE SOUTH. 07.22Z RAP 925-700MB MOISTURE TRANSPORT FOR EARLY THIS EVENING IS FOCUSED MORE INTO NEBRASKA...THEN VEERS EAST INTO IOWA AND FOCUSES JUST SOUTH OF THE FORECAST AREA. THUS...IT IS ENTIRELY POSSIBLE THE FORECAST AREA MOSTLY ENDS UP DRY TONIGHT. OVERALL PRECIPITATION CHANCES SEEM REASONABLE FOR NOW...BUT MAY HAVE TO LOWER THEM OR DRY THEM OUT ENTIRELY IN A FEW HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 305 PM CDT SUN JUL 7 2013 THE MAIN FOCUS GOING INTO TOMORROW IS WITH THE CHANCES FOR RAIN SHOWERS/THUNDERSTORMS AS A COLD FRONT MOVES THROUGH THE REGION. CURRENTLY...A HUMID AIR MASS IS IN PLACE AT THE SURFACE AS DEW POINTS CONTINUE TO RISE IN RESPONSE TO AN INCREASE OF LOW LEVEL MOISTURE TRANSPORT OUT OF THE GULF. SURFACE ANALYSIS SHOWS TWO COLD FRONTS IN THE VICINITY OF WESTERN MINNESOTA. THE FIRST ONE EXTENDS FROM NORTHERN WISCONSIN DOWN THROUGH SOUTH CENTRAL MINNESOTA AND EASTERN NEBRASKA. THE SECOND COLD FRONT IS JUST TO THE WEST OF THIS OTHER FRONT AND EXTENDS FROM A SURFACE LOW IN SOUTHERN MANITOBA DOWN THROUGH WESTERN MINNESOTA AND EASTERN SOUTH DAKOTA. WITH DEW POINTS IN THE LOW 70S BETWEEN THESE TWO FRONTS...07.19Z RAP ANALYSIS SHOWS AN AXIS OF 3000 J/KG OF SURFACE BASED CAPE. CONVECTION HAS INITIATED ALONG THE FIRST FRONT AND A LAKE BREEZE BOUNDARY NORTHWEST OF THE TWIN CITES AND DOWN ALONG THE FRONT. FURTHER ALOFT...MID LEVEL RIDGING EXTENDS FROM THE SOUTHERN PLAINS THROUGH THE UPPER GREAT LAKES. A MID LEVEL SHORT WAVE TROUGH IS CURRENT IN THE DAKOTAS AND WILL TRACK TO THE EAST THROUGH TONIGHT AND IS TIED TO THE SECONDARY COLD FRONT. THE ENVIRONMENT AHEAD OF THE COLD FRONTS APPEARS TO BE CAPPED AROUND 800MB...SO AM NOT EXPECTING ANY DEVELOPMENT OUT IN THE WARM SECTOR DESPITE THE HIGH CAPE ENVIRONMENT. THE MAIN CHANCES WILL BE AS THE FRONT AND WEAKENING MID LEVEL TROUGH COME THROUGH THIS EVENING AND OVERNIGHT. THE FRONT WILL THEN PUSH THROUGH AND STALL TO THE SOUTH OF THE REGION IN IOWA ON MONDAY. HAVE DROPPED THE PRECIPITATION CHANCES DOWN A LITTLE ON MONDAY AS IT LOOKS LIKE SURFACE TO UPPER LEVEL RIDGING WILL SETTLE IN FOR A BRIEF PERIOD AND KEEP THE REGION MORE ON THE DRY SIDE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 305 PM CDT SUN JUL 7 2013 THE MAIN FOCUS IN THE LONG TERM IS ON MONDAY NIGHT INTO TUESDAY AND WITH WHERE A MESOSCALE CONVECTIVE SYSTEM WILL DEVELOP AND TRACK THROUGH ON TUESDAY MORNING. THE 07.12Z GUIDANCE CONTINUES TO GIVE SOME UNCERTAINTY WITH THE TRAJECTORY OF THIS MCS. THE GFS/NAM TAKE A MORE SOUTHERLY ROUTE ACROSS IOWA DUE TO THE LOW LEVEL JET/MOISTURE TRANSPORT ONLY REACHING EASTERN NEBRASKA BY 6Z TUESDAY. THE PREFERRED GUIDANCE IS FROM THE ECMWF/GEM SOLUTION WHICH PUSH THE LLJ NOSE INTO EASTERN SOUTH DAKOTA BY THIS TIME...AND DESPITE THE GEM/ECMWF SHOWING THE MAIN QPF STAYING WELL TO THE NORTH OF THE REGION TOWARD DULUTH...AM CONCERNED THAT THE MCS WOULD DEVELOP IN WESTERN MINNESOTA AND RUN EAST SOUTHEAST ALONG THE NOSE OF THE LOW LEVEL JET AND INSTABILITY GRADIENT. THIS IDEA FOLLOWS WELL WITH FORECAST CORFIDI VECTORS WHICH POINT TO THE SOUTHEAST TUESDAY MORNING...WHICH WOULD TAKE IT STRAIGHT THROUGH THE MIDDLE OF THE FORECAST AREA ALONG THE MINNESOTA/IOWA BORDER INTO WESTERN WISCONSIN. GIVEN THE MODEL DIFFERENCES...HAVE NOT HIT THE PRECIPITATION CHANCES TOO HIGH YET AND WILL HAVE TO SEE HOW THE PATTERN EVOLVES INTO TOMORROW. WITH THE INCREASING MOISTURE TRANSPORT AND POTENTIAL FOR HEAVY RAIN...FLASH FLOODING WILL BE A THREAT DESPITE THE RECENT DRY SPELL. DETAILS ARE OUTLINED IN THE HYDROLOGY AFD SECTION. THIS MCS CAUSES SOME HAVOC GOING INTO THE AFTERNOON ON TUESDAY AND WHAT THE SEVERE THUNDERSTORM CHANCES ARE AFTER ITS PASSAGE. IF THE SYSTEM TRACKS TO THE SOUTH...THEN IT LIKELY KEEPS THE MAIN WARM FRONT DOWN THERE AS WELL AND LIMITS THE SEVERE POTENTIAL. IF IT TRACKS THROUGH THE HEART OF THE FORECAST AREA...AS WE THINK IT MAY...THE QUESTION WILL BE HOW FAST DOES IT CLEAR AND ALLOW THE ENVIRONMENT TO RECHARGE BY PEAK HEATING. IF THE SYSTEM WERE TO CLEAR EARLY ENOUGH AND ALLOW FOR DESTABILIZATION BY LATE AFTERNOON OUR SEVERE THREAT WOULD BE FAIRLY HIGH DUE TO A VEERING 0-6KM SHEAR PROFILE...HIGH INSTABILITY...AND DEEP FORCING FROM A SURFACE LOW AND MID LEVEL TROUGH. WITH A LINGERING OUTFLOW BOUNDARY/WARM FRONT IN THE REGION...THE HAZARDS WOULD INCLUDE LARGE HAIL...FLASH FLOODING...DAMAGING WINDS AND THE POSSIBILITY OF A TORNADO OR TWO GIVEN THE HIGH 0-1KM SHEAR/HELICITY. THE THING IS...CONFIDENCE IS JUST NOT THERE YET TO LEAN ONE WAY OR ANOTHER UNTIL THERE IS BETTER CONSENSUS ON THE TRACK OF THE EARLY MORNING MCS. BEYOND THIS SYSTEM...IT LOOKS LIKE A DRY AND SEASONAL PERIOD THROUGH THE REST OF THE WEEK AS UPPER LEVEL RIDGING SETS UP ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. A COLD FRONT WILL APPROACH THE REGION FROM THE WEST BY NEXT WEEKEND AND COULD BRING THE NEXT SHOT OF RAIN ALONG WITH IT. THERE ARE SOME TIMING DIFFERENCES BETWEEN THE 07.12Z GFS AND ECMWF WITH THIS FEATURE THAT WILL BE RUNNING INTO THE RIDGING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1122 PM CDT SUN JUL 7 2013 A TROUGH OF LOW PRESSURE AT 05Z STRETCHED FROM OMAHA TO ROCHESTER AND EAU CLAIRE...DROPPING SOUTHEAST WITH TIME. SOME SHOWERS ALONG THIS TROUGH WERE IMPACTING RST...BUT THE END WAS RAPIDLY APPROACHING SUCH THAT THE 06Z TAF STARTS OFF DRY. SHOWERS APPEAR THAT THEY WILL MISS LSE...BUT COULD FORM NEARBY SO PUT A VCSH IN THE TAF THERE BETWEEN 06-09Z. HIGH PRESSURE THEN BUILDS IN BEHIND THE TROUGH FOR MONDAY...BRINGING WITH IT CLEARING SKIES AND DRIER AIR. REGARDING FOG POTENTIAL IN THE WAKE OF THE TROUGH FOR LATE TONIGHT...GIVEN LITTLE IF ANY PRECIPITATION OCCURRING AND POTENTIAL FOR CLOUDS AROUND TO KEEP TEMPERATURE/DEWPOINT SPREADS HIGH...CONCERN FOR FOG IS LOW. RAISED VISIBILITIES UP TO VFR FOR THAT 09-13Z TIME PERIOD. WINDS DURING THE NEXT 24 HOURS LOOK QUITE LIGHT...GENERALLY 5 KT OR LESS....WITH A WEAK PRESSURE GRADIENT IN PLACE. HEADING INTO MONDAY NIGHT...PARTICULARLY AFTER 06Z...THE TROUGH OF LOW PRESSURE LOOKS TO MARCH BACK NORTH AS A WARM FRONT TOWARDS THE TAF SITES. WILL NEED TO WATCH POTENTIAL FOR SHOWERS AND THUNDERSTORMS LATE IN THE NIGHT OR PERHAPS TUESDAY MORNING. && .HYDROLOGY...TUESDAY ISSUED AT 305 PM CDT SUN JUL 7 2013 THE MAIN HYDRO CONCERNS COME IN ON TUESDAY AS A COMPLEX OF THUNDERSTORMS IS FORECAST TO TRACK THROUGH THE REGION. THE QUESTION IS WHERE AND WHEN WILL IT COME THROUGH? MOST OF THE MODEL GUIDANCE SUGGEST THAT THIS SYSTEM WILL FORM IN NORTHWEST NEBRASKA AND RUN EAST ACROSS IOWA MONDAY NIGHT INTO TUESDAY MORNING. WITH SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP AHEAD OF THIS COMPLEX NORTH OF A WARM FRONT...THE POTENTIAL IS THERE FOR SOME HEAVY RAIN TO FALL. THANKFULLY...CONDITIONS HAVE BEEN DRY FOR THE PAST WEEK...SO FLASH FLOOD GUIDANCE HAS COME UP CONSIDERABLY AND THE SOIL SHOULD BE ABLE TO HANDLE THE EXCESS MOISTURE REASONABLY WELL FOR A PERIOD. THAT SAID...INCREASING PRECIPITABLE WATER VALUES AND LOW LEVEL MOISTURE TRANSPORT AIMING INTO THE REGION...EXPECT THAT HEAVY RAIN AND FLASH FLOODING IS POSSIBLE WITH SOME RENEWED RISES ON AREA RIVERS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...AJ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...AJ HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION...CORRECTED
NWS LITTLE ROCK AR
331 AM CDT WED JUL 10 2013 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT CONVECTION WAS ONGOING ACROSS PARTS OF SOUTHERN/CENTRAL MISSOURI EARLY THIS MORNING. FURTHER NORTH A FRONTAL BOUNDARY STRETCHED ACROSS NORTHERN KANSAS AND UP INTO SOUTHEASTERN IOWA. THE FORECAST TODAY IS SOMEWHAT TRICKY AS A RESULT OF THESE TWO FEATURES. THE ONGOING CONVECTION HAS SENT OUT SOME OUTFLOW BOUNDARIES THAT SHOULD WORK INTO NRN ARKANSAS BY MID MORNING. THE 4KM WRF AND ALSO THE RAPID REFRESH RUC SUGGEST THESE BOUNDARIES WILL LIKELY BE A FOCUS FOR MIDDAY AND AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY SOUTH OF THE I-40 CORRIDOR. HOWEVER THE FRONTAL BOUNDARY WILL MOVE IN DURING THE EVENING HOURS...UPON WHICH THE MORE COARSE MODELS SUGGEST WILL BE MORE DOMINANT SHOWER/THUNDERSTORM ACTIVITY. TRENDED THE FORECAST IN THE DIRECTION OF THE FORMER...WITH SLIGHTLY COOLER /WE ARE TALKING ABOUT 1-2 DEGREES HERE/ AFTERNOON HIGHS UP NORTH THAN GUIDANCE SUGGESTS...AND PLAYED RAIN CHANCES TOWARDS THE SOUTHERN ISOLD TO SCT VARIETY INSTEAD OF CONVECTION BEING TIED TO THE FRONT. THAT SAID...DID LEAVE SLIGHT CHANCES IN THE NORTH THROUGH THE DAY AND INTO TONIGHT TO ACCOUNT FOR CONVECTION ALONG THE FRONT. OTHERWISE...NOT MUCH TO TALK ABOUT IN THE EXTENDED. THE AFOREMENTIONED FRONT WILL PUSH WELL INTO THE STATE BY THURSDAY. UPPER LEVEL HIGH PRESSURE SITUATED OVER THE PLAINS WILL BECOME HIGHLY AMPLIFIED BY LATE THURSDAY. LEFT SOME SLIGHT RAIN CHANCES OVER THE FAR SOUTH AND FAR SOUTHWEST PARTS OF THE FORECAST AREA THU AND FRI AFTERNOONS. THERE IS SOME QPF SIGNAL IN NUMERICAL MODELS BOTH DAYS IN THOSE REGIONS...WHICH SEEMS REASONABLE. TEMPERATURES WILL NOT COOL DOWN MUCH IN THE SOUTHWEST...BUT HIGHS IN THE NORTHEAST BY FRIDAY WILL LIKELY NOT REACH 90 DEGREES. HOWEVER DRIER AIR WILL FILTER IN ACROSS ARKANSAS SO EVEN WITH HIGHS IN THE LOW 90S ACROSS THE SOUTHWEST HALF OF THE STATE...THERE WILL BE SOME RELIEF FROM THE HOT AND MUGGY CONDITIONS HEADING INTO THE WEEKEND. && .LONG TERM...SATURDAY NIGHT THROUGH TUESDAY THE LONG TERM OFFERS AN ODD SYNOPTIC SETUP FOR JULY. AT THE BEGINNING...THE RETROGRADING CUTOFF LOW WILL BE MOVING INTO COASTAL TEXAS...WITH AN ELONGATED UPPER RIDGE SETTING UP OVER THE PLAINS. THE AFOREMENTIONED LOW WILL BRING MOISTURE UP INTO THE REGION...AND WITH IT A CHANCE OF SHOWERS/STORMS EACH DAY...WHICH SHOULD MOSTLY BE DIURNALLY DRIVEN. WILL CONTINUE TO KEEP RAIN CHANCES SMALL TO ACCOUNT FOR UNCERTAINTIES WITH THIS SETUP. IF YOU CAN BELIEVE YOUR EYES...THE EXACT SAME THING LOOKS TO HAPPEN BY LATE MONDAY INTO TUESDAY...AS THE MODELS ADVERTISE ANOTHER CUTOFF UPPER LOW FORMING AND RETROGRADING TOWARD THE MID SOUTH REGION. THIS WILL BRING A REINFORCING SHOT OF AT LEAST SMALL RAIN CHANCES TO END THE PERIOD. INITIALLY...TEMPERATURES WILL BE A LITTLE BELOW SEASONAL AVERAGES DUE TO EASTERLY SURFACE FLOW. BY MONDAY AND TUESDAY...TEMPERATURES WILL BE A BIT WARMER...BUT WILL BE KEPT IN CHECK BY CLOUD COVER ASSOCIATED WITH THE UPPER LOWS. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 97 73 90 67 / 20 20 10 10 CAMDEN AR 96 74 95 72 / 30 30 20 20 HARRISON AR 94 72 90 66 / 20 20 10 10 HOT SPRINGS AR 97 75 95 72 / 30 30 20 10 LITTLE ROCK AR 96 75 95 70 / 30 30 20 10 MONTICELLO AR 95 75 94 72 / 30 30 20 10 MOUNT IDA AR 96 75 94 71 / 30 30 20 10 MOUNTAIN HOME AR 96 71 90 66 / 20 20 10 10 NEWPORT AR 96 73 90 67 / 20 20 10 10 PINE BLUFF AR 94 75 94 70 / 30 30 20 10 RUSSELLVILLE AR 98 75 95 71 / 30 20 20 10 SEARCY AR 96 74 92 68 / 30 20 10 10 STUTTGART AR 97 74 93 69 / 30 30 20 10 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...64 / LONG TERM...57
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
330 AM CDT WED JUL 10 2013 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT CONVECTION WAS ONGOING ACROSS PARTS OF SOUTHERN/CENTRAL MISSOURI EARLY THIS MORNING. FURTHER NORTH A FRONTAL BOUNDARY STRETCHED ACROSS NORTHERN KANSAS AND UP INTO SOUTHEASTERN IOWA. THE FORECAST TODAY IS SOMEWHAT TRICKY AS A RESULT OF THESE TWO FEATURES. THE ONGOING CONVECTION HAS SENT OUT SOME OUTFLOW BOUNDARIES THAT SHOULD WORK INTO NRN ARKANSAS BY MID MORNING. THE 4KM WRF AND ALSO THE RAPID REFRESH RUC SUGGEST THESE BOUNDARIES WILL LIKELY BE A FOCUS FOR MIDDAY AND AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY SOUTH OF THE I-40 CORRIDOR. HOWEVER THE FRONTAL BOUNDARY WILL MOVE IN DURING THE EVENING HOURS...UPON WHICH THE MORE COARSE MODELS SUGGEST WILL BE MORE DOMINANT SHOWER/THUNDERSTORM ACTIVITY. TRENDED THE FORECAST IN THE DIRECTION OF THE FORMER...WITH SLIGHTLY COOLER /WE ARE TALKING ABOUT 1-2 DEGREES HERE/ AFTERNOON HIGHS UP NORTH THAN GUIDANCE SUGGESTS...AND PLAYED RAIN CHANCES TOWARDS THE SOUTHERN ISOLD TO SCT VARIETY INSTEAD OF CONVECTION BEING TIED TO THE FRONT. THAT SAID...DID LEAVE SLIGHT CHANCES IN THE NORTH THROUGH THE DAY AND INTO TONIGHT TO ACCOUNT FOR CONVECTION ALONG THE FRONT. OTHERWISE...NOT MUCH TO TALK ABOUT IN THE EXTENDED. THE AFOREMENTIONED FRONT WILL PUSH WELL INTO THE STATE BY THURSDAY. UPPER LEVEL HIGH PRESSURE SITUATED OVER THE PLAINS WILL BECOME HIGHLY AMPLIFIED BY LATE THURSDAY. LEFT SOME SLIGHT RAIN CHANCES OVER THE FAR SOUTH AND FAR SOUTHWEST PARTS OF THE FORECAST AREA THU AND FRI AFTERNOONS. THERE IS SOME QPF SIGNAL IN NUMERICAL MODELS BOTH DAYS IN THOSE REGIONS...WHICH SEEMS REASONABLE. TEMPERATURES WILL NOT COOL DOWN MUCH IN THE SOUTHWEST...BUT HIGHS IN THE NORTHEAST BY FRIDAY WILL LIKELY NOT HIGH 90 DEGREES. HOWEVER DRIER AIR WILL FILTER IN ACROSS ARKANSAS SO EVEN WITH HIGHS IN THE LOW 90S ACROSS THE SOUTHWEST HALF OF THE STATE THROUGH THE SHORT TERM...THERE WILL BE SOME RELIEF FROM THE HOT AND MUGGY CONDITIONS HEADING INTO THE WEEKEND. && .LONG TERM...SATURDAY NIGHT THROUGH TUESDAY THE LONG TERM OFFERS AN ODD SYNOPTIC SETUP FOR JULY. AT THE BEGINNING...THE RETROGRADING CUTOFF LOW WILL BE MOVING INTO COASTAL TEXAS...WITH AN ELONGATED UPPER RIDGE SETTING UP OVER THE PLAINS. THE AFOREMENTIONED LOW WILL BRING MOISTURE UP INTO THE REGION...AND WITH IT A CHANCE OF SHOWERS/STORMS EACH DAY...WHICH SHOULD MOSTLY BE DIURNALLY DRIVEN. WILL CONTINUE TO KEEP RAIN CHANCES SMALL TO ACCOUNT FOR UNCERTAINTIES WITH THIS SETUP. IF YOU CAN BELIEVE YOUR EYES...THE EXACT SAME THING LOOKS TO HAPPEN BY LATE MONDAY INTO TUESDAY...AS THE MODELS ADVERTISE ANOTHER CUTOFF UPPER LOW FORMING AND RETROGRADING TOWARD THE MID SOUTH REGION. THIS WILL BRING A REINFORCING SHOT OF AT LEAST SMALL RAIN CHANCES TO END THE PERIOD. INITIALLY...TEMPERATURES WILL BE A LITTLE BELOW SEASONAL AVERAGES DUE TO EASTERLY SURFACE FLOW. BY MONDAY AND TUESDAY...TEMPERATURES WILL BE A BIT WARMER...BUT WILL BE KEPT IN CHECK BY CLOUD COVER ASSOCIATED WITH THE UPPER LOWS. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 97 73 90 67 / 20 20 10 10 CAMDEN AR 96 74 95 72 / 30 30 20 20 HARRISON AR 94 72 90 66 / 20 20 10 10 HOT SPRINGS AR 97 75 95 72 / 30 30 20 10 LITTLE ROCK AR 96 75 95 70 / 30 30 20 10 MONTICELLO AR 95 75 94 72 / 30 30 20 10 MOUNT IDA AR 96 75 94 71 / 30 30 20 10 MOUNTAIN HOME AR 96 71 90 66 / 20 20 10 10 NEWPORT AR 96 73 90 67 / 20 20 10 10 PINE BLUFF AR 94 75 94 70 / 30 30 20 10 RUSSELLVILLE AR 98 75 95 71 / 30 20 20 10 SEARCY AR 96 74 92 68 / 30 20 10 10 STUTTGART AR 97 74 93 69 / 30 30 20 10 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...64 / LONG TERM...57
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
1130 PM PDT TUE JUL 9 2013 .SYNOPSIS... MONSOONAL MOISTURE WILL GRADUALLY INCREASE THROUGH WEDNESDAY WITH A GREATER INFLUX ON WEDNESDAY NIGHT AND THURSDAY. SLOW DRYING FROM FRIDAY THROUGH MONDAY WITH ANOTHER BIGGER INFLUX OF MONSOONAL MOISTURE POSSIBLE AROUND THE MIDDLE OF NEXT WEEK. A FEW SPRINKLES ARE POSSIBLE TONIGHT INTO WEDNESDAY MORNING WITH A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS WEDNESDAY AFTERNOON. THE INCREASING MOISTURE ON WEDNESDAY NIGHT AND THURSDAY WILL BRING COOLER DAYTIME TEMPERATURES AND GREATER CHANCES FOR SHOWERS AND THUNDERSTORMS. A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS FOR THE MOUNTAINS AND DESERTS WILL CONTINUE ON FRIDAY THROUGH THE WEEKEND WITH GRADUAL INLAND WARMING. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... UPDATE FOR THE REST OF TONIGHT INTO WEDNESDAY MORNING TO ACCOUNT FOR SATELLITE AND RADAR TRENDS AND RELATED HRRR FORECASTS THAT SHOW ELEVATED CONVECTION DEVELOPING OVER SAN DIEGO COUNTY LATE THIS EVENING...THEN SPREADING NORTHWESTWARD OVERNIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BRING SOME SPRINKLES OR VERY LIGHT MEASURABLE AMOUNTS. PREVIOUS DISCUSSION... WATER VAPOR IMAGERY CONTINUES TO SHOW HIGH PRESSURE CENTERED OVER THE FOUR CORNERS THIS EVENING...EXTENDING BACK TOWARDS SOUTHERN CALIFORNIA. SUBTROPICAL MOISTURE IS ROTATING AROUND THIS HIGH...AND SPREADING INTO SOUTHERN CALIFORNIA...MAKING FOR A NICE SUNSET THIS EVENING. THE 00Z KNKX SOUNDING SHOWS THAT PRECIPITABLE WATER VALUES ARE UP TO 1.26 INCHES...BUT THIS MOISTURE IS STILL AT OR WELL ABOVE 600 MBS...WITH A VERY DRY LAYER BELOW 600 MBS. THAT BEING SAID...ONE SHOWER DID DEVELOP THIS AFTERNOON OVER SANTA ROSA MOUNTAIN...PRODUCING A DECENT LITTLE RAIN SHOWER. THE RADAR IS NOW QUIET...WITH TEMPERATURES WITHIN A FEW DEGREES OF THIS TIME LAST NIGHT. THE MOST NOTICEABLE DIFFERENCES AT THIS TIME THOUGH ARE WITH THE HIGH CLOUDS SPREADING ACROSS THE REGION AND THE SURGE OF HIGHER DEW POINTS IN THE SOUTHERN DESERTS. IN FACT...THERMAL IS CURRENTLY 89 OVER 75...MAKING FOR A VERY MUGGY EVENING. NEEDLESS TO SAY...IT WILL LIKELY BE ANOTHER WARM NIGHT IN THESE AREAS. THE SUBTROPICAL MOISTURE WILL CONTINUE TO SPREAD INTO SOUTHERN CALIFORNIA THROUGH WEDNESDAY...WITH A GRADUAL COOLING TREND POSSIBLE. HOWEVER...HUMIDITY VALUES WILL BE ON THE RISE...MAKING IT FEEL VERY MUGGY ACROSS THE SOUTHLAND. AT THIS TIME...THE LATEST MODELS CONTINUE TO SHOW THAT THE BRUNT OF THE MOISTURE WILL REMAIN ABOVE 600 MBS THROUGH TOMORROW...WITH JUST A FEW ISOLATED AFTERNOON SHOWERS OR THUNDERSTORMS POSSIBLE OVER THE MOUNTAINS. THAT BEING SAID...THE BETTER THREAT OF SHOWERS AND THUNDERSTORMS WILL DEVELOP LATE WEDNESDAY NIGHT INTO THURSDAY...AS A EASTERLY WAVE MOVING ACROSS CHIHUAHUA...ROUNDS THE RIDGE CORNER AND LIFTS ACROSS SOUTHERN CALIFORNIA. AS THIS DISTURBANCE MOVES ACROSS THE REGION...THE VALLEYS AND POTENTIALLY THE COASTAL AREAS MAY ALSO SEE A FEW SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES WILL BE WELL OVER 1.5 INCHES ACROSS THE SOUTHLAND...AND APPROACH 1.8 IN THE SOUTHERN DESERTS. THEREFORE...THINK THAT THE THREAT OF FLASH FLOODING WILL ALSO DEVELOP DURING THE DAY ON THURSDAY...ESPECIALLY FOR THE MOUNTAINS AND DESERTS. THE THREAT OF SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE WEEKEND...BUT WILL BE MORE THE MORE TYPICAL SUMMER DIURNAL TYPE THUNDERSTORMS. DRIER CONDITIONS WILL DEVELOP BY MONDAY...BUT ANOTHER SURGE OF SUBTROPICAL MOISTURE WILL HEAD THIS WAY FOR MID WEEK. && .AVIATION... 100410Z...COAST/VALLEYS...AREAS OF STRATUS WILL DEVELOP ALONG THE COAST...MAINLY BETWEEN 06Z AND 09Z AND SPREAD 10-15 MI INLAND BY 12Z. BASES WILL BE 700-1000 FT MSL WITH TOPS TO 1200 FT MSL. STRATUS WILL PROBABLY REACH KSNA LATE TONIGHT...UNLIKE THE PAST 2 NIGHTS. STRATUS WILL MOSTLY DISSIPATE AROUND 16-17Z WED. STRATUS WILL HAVE LESS COVERAGE WED NIGHT. OTHERWISE...MOSTLY BKN CLOUDS ABOVE 13000 FT MSL WILL PREVAIL THROUGH WED NIGHT. MTNS/DESERTS...BKN CLOUDS ABOVE 13000 FT MSL WILL PREVAIL THROUGH WED NIGHT. AREAS OF CU/TCU WITH BASES 8000-9000 FT MSL WILL DEVELOP AGAIN WED AFTERNOON...AND ISOLATED TSTORMS WILL BE POSSIBLE WITH TOPS TO 35000 FT MSL. && .MARINE... 2.5 FOOT/15 SECOND SWELL FROM 180 DEG WILL CONTINUE THROUGH WED...THEN A LONG-PERIOD SWELL FROM 170 DEG WILL BUILD WED NIGHT/EARLY THU. THE SWELL WILL INITIALLY HAVE A PERIOD OF AROUND 20 SECONDS BUT A HEIGHT OF ONLY 2 FEET...THEN THU/FRI THE HEIGHT WILL BE 3-4 FEET BUT WITH A PERIOD SHORTENING TO 15-17 SECONDS. GIVEN THE STEEP ANGLE TO THE COAST...MOST OF THE ENERGY WILL BYPASS SAN DIEGO COUNTY...EXCEPT MAINLY NORTH OF CARLSBAD AND NEAR PT LOMA. IN ORANGE COUNTY...THE ANGLE WILL RESULT IN ABOUT 60 PERCENT OF THE ENERGY AVAILABLE FOR THE WAVES...SO 4-6 FOOT SURF WITH LOCAL SETS AROUND 8 FEET ARE LIKELY THU/FRI. LONG SHORE CURRENTS WILL DEVELOP...ALONG WITH THE TYPICAL STRONG RIP CURRENTS WITH THESE WAVE HEIGHTS. ANOTHER SSW SWELL WILL ARRIVE SAT TO KEEP SURF ABOVE NORMAL ALONG S-FACING BEACHES. && .FIRE WEATHER... SUBTROPICAL MOISTURE WILL CONTINUE TO SPREAD ACROSS SOUTHERN CALIFORNIA THE NEXT FEW DAYS...WITH COOLER CONDITIONS DEVELOPING AND HUMIDITY VALUES GRADUALLY IMPROVING. THERE WILL BE A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS ON WEDNESDAY...WITH A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT AND THURSDAY. AS THE LOWER ATMOSPHERE MOISTENS...THE CHANCE OF WETTING RAINS WILL IMPROVE AS WELL...WITH ISOLATED FLASH FLOODING POSSIBLE BY THURSDAY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...BEACH HAZARDS STATEMENT THROUGH LATE SATURDAY NIGHT FOR THE BEACHES IN THE ORANGE COUNTY COASTAL AREAS. BEACH HAZARDS STATEMENT FROM LATE WEDNESDAY NIGHT THROUGH LATE SATURDAY NIGHT FOR THE SAN DIEGO COUNTY COASTAL AREAS. PZ...NONE. && $$ UPDATE...17 SYNOPSIS...BA PUBLIC/FIRE...PALMER AVIATION/MARINE...MAXWELL
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
344 AM MDT WED JUL 10 2013 .SHORT TERM...AN UPPER LEVEL HIGH WILL REMAIN OVER THE SRN ROCKIES WITH MDT WNW FLOW ALOFT ACROSS NRN CO. AT THE SFC LOW PRES WILL BE OVER THE MTNS AS SFC HIGH PRES IS OVER THE CNTRL US. THUS ALLOWS FOR INCREASING SELY LOW LVL FLOW EAST OF THE MTNS BY AFTN INTO TONIGHT. CURRENTLY LOW LVL MOISTURE HAS INCREASED BEHIND WEAK COOL FNT ACROSS MOST OF THE PLAINS AS A WEAK DENVER CYCLONE HAS DEVELOPED. MEANWHILE AN UPPER LEVEL JET IS POSITIONED OVER THE FAR NERN CORNER WHICH HAS BEEN ALLOWING FOR SCT SHOWERS EARLY THIS MORNING. FOR THIS AFTN MOST OF THE SHORT RANGE MODELS SHOW S TO SE LOW LVL FLOW EAST OF THE MTNS WITH NO HINTS OF A DENVER CYCLONE EXCEPT FOR THE WRF WHICH KEEPS IT INTACT. IF THE CYCLONE STAYS INTACT THEN A CONVERGENCE ZONE WILL SET UP ALONG THE FRONT RANGE AND BE A FOCUS FOR TSTM DEVELOPMENT. IF THE CYCLONE IS WIPED OUT THEN CONVECTIVE DEVELOPMENT WILL HAVE TO RELY ON OUTFLOW BOUNDARIES FROM TSTMS OVER THE HIGHER TERRAIN WHICH COULD KEEP BEST CHC OF TSTMS EAST OF THE URBAN CORRIDOR. FOR NOW THERE IS TOO MUCH UNCERTAINTY TO MONKEY AROUND WITH THE CURRENT CHC POPS SO WILL JUST LEAVE AS IS. SFC BASED CAPES BY AFTN DEPENDING ON HOW MUCH MIXING OCCURS LOOK TO BE AROUND 1000-1500 J/KG ALONG THE FRONT RANGE TO NEAR 3000 J/KG OVER THE NERN PLAINS. WITH WNW MID LVL FLOW IN THE 25-30 KT RANGE SHEAR WILL BE FAVORABLE FOR A FEW SVR STORMS ESPECIALLY WHERE THE HIGHER CAPES RESIDE OVER THE PLAINS WITH LARGE HAIL AND STRONG WINDS AND POSSIBLY A TORNADO. AS FOR HIGHS THIS AFTN IF YOU BELIEVE THE HRRR AND RAP READINGS ALONG THE FRONT RANGE WILL BE JUST AS HOT AS YESTERDAY WHILE READINGS OVER THE NERN PLAINS WILL BE MAINLY IN THE UPPER 80S TO AROUND 90. FOR NOW WILL KEEP READINGS IN THE UPPER 80S TO LOWER 90S WITH THE WARMEST VALUES CLOSER TO THE FOOTHILLS. NATURALLY IF THE HRRR AND RAP ARE RIGHT MY HIGHS WILL BE OFF BY AROUND 5 DEGREES OVER THE URBAN CORRIDOR. FOR TONIGHT THE TSTMS OVER THE PLAINS SHOULD GRADUALLY DEVELOP INTO AN MCS AND MOVE ESE OUT OF THE AREA BY AROUND MIDNIGHT. ONCE AGAIN COULD SEE A FEW SVR STORMS OVER THE PLAINS DURING THE EARLY EVENING HOURS. WITH HIGH PRECIPITABLE VALUES SOME AREAS OVER THE PLAINS COULD SEE QUITE A BIT OF RAINFALL. IN THE MTNS AND FOOTHILLS TSTM CHANCES SHOULD MOSTLY END BY 00Z. .LONG TERM...BY THURSDAY...MODEL CONSENSUS INDICATES THE 500MB RIDGE AXIS ALIGNED WITH THE SPINE OF THE COLORADO/NEW MEXICO ROCKIES WHICH PLACES NORTHEAST COLORADO UNDER A LIGHT NORTHWESTERLY FLOW ALOFT. THIS FLOW DOES LITTLE TO COOL TEMPERATURES ON THURSDAY. MATTER OF FACT...700 MB TEMPERATURES WARM A FEW DEGS C FOLLOWING THE SLIGHT POST-FRONTAL COOL DOWN ON WEDNESDAY. SHOULD SEE LOW/MID 90S FOR AFTERNOON READINGS ON THE PLAINS...LOW-MID 80S IN THE MTN VALLEYS AND 60S-70S FOR HIGH TEMPS AT HIGHER ELEVATIONS. STRONG SUBSIDENCE INVERSION AT MID-LEVELS AND LOWER PRECIPITABLE WATER VALUES SHOULD SIGNIFICANTLY REDUCE THE CHANCE OF T-STORMS ON THURSDAY... PARTICULARLY EAST OF THE MOUNTAINS. ALTHOUGH MODELS SHOW LOW/MID- LEVEL MOISTURE CREEPING UP ON THE PLAINS LATE IN THE DAY WITH INCREASING SOUTHERLY LOW-LEVEL FLOW. COULD SEE ISOLATED T-STORMS FORMING ALONG THE FRONT RANGE BY LATE AFTERNOON AND/OR EARLY EVENING...THEN DRIFTING NORTHEASTWARD OVER THE NEARBY PLAINS WHERE THEY SHOULD DIE A QUICK DEATH WITH A STRONG CAP IN PLACE. ON FRIDAY...MODELS SHOW THE UPPER RIDGE POSITIONED OVER THE ROCKY MOUNTAIN REGION UNDERGOING A POSITIVE TILT AS IT MIGRATES SLOWLY OVER THE WESTERN GREAT PLAINS. THE TILT RESULTS IN A SHIFT TO SOUTHWEST FLOW ALOFT OVER COLORADO WHICH THEN BEGINS TO ADVECT MOISTURE LADEN SUBTROPICAL AIR UP FROM THE DESERT SOUTHWEST. AT THE CORE OF THE 700-500 MB MOISTURE PLUME ARE 6-8 G/KG SPECIFIC HUMIDITIES...WHICH MODELS SHOW SPREADING NORTHWARD OVER WESTERN COLORADO THROUGH THE DAY. BY LATE ON FRIDAY WITH THE 700-500MB HIGH CENTERED OVER SOUTH-CENTRAL KANSAS/NORTH-CENTRAL OKLAHOMA...THIS PLUME OF MOIST SUBTROPICAL AIR ADVANCES EASTWARD OVER EASTERN COLORADO WHERE IT AIDS IN THUNDERSTORM DEVELOPMENT. BY LATE AFTERNOON...COMPUTED SFC BASED CAPES UP AROUND 1500 J/KG ON THE PLAINS AND MARGINAL SHEAR...MAY SEE ONE OR TWO LATE DAY STORMS BECOME SEVERE...BUT WELL EAST OF THE I-25 URBAN CORRIDOR. THERE/S A GREATER RISK FOR LOCALLY HEAVY RAINFALL FROM SLOW MOVING T-STORMS FORMING ALONG OUTFLOW BOUNDARIES. WILL NEED TO CLOSELY MONITOR RECENT BURN SCARS AS LESS THAN A HALF INCH OF RAIN IN A SHORT PERIOD OF TIME COULD CAUSE HEAVY RUNOFF PROBLEMS. TEMPERATURES ON FRIDAY ABOUT THE SAME AS THOSE ON THURSDAY...BUT PROBABLY OCCURRING EARLIER IN THE DAY BEFORE THE ANTICIPATED CLOUD BUILDUP.SHOWERS/STORMS EXPECTED TO LINGERING INTO THE EVENING HOURS WITH THE AXIS OF THE PLUME BISECTING THE FCST AREA FROM SOUTHWEST-TO-NORTHEAST. STORM INTENSITY SHOULD BE LOW...WHILE THE POTENTIAL FOR LOCALLY HEAVY RAIN WILL STILL EXIST. OVER THE WEEKEND...THE UPPER RIDGE GOES THROUGH SOME CHANGES AS IT SPLITS INTO TWO PIECES...ONE PART MIGRATING ACROSS THE UPPER MIDWEST...WHILE THE OTHER PART GAINING STRENGTH NEAR THE FOUR CORNERS. THIS INITIALLY THINS OUT THE PLUME OF SUBTROPICAL MOISTURE STREAMING OVER COLORADO. HOWEVER BY LATE ON SATURDAY THE MONSOONAL FLOW OF MOIST AIR RESUMES...RESULTING IN ANOTHER ROUND OF SCATTERED SHOWERS/T-STORMS SATURDAY AFTERNOON AND EVENING...SOME POSSIBLY PRODUCING LOCALLY HEAVY RAINFALL. HOWEVER STORM DEVELOPMENT ON SUNDAY APPEARS TO CONCENTRATE MORE OVER THE HIGH COUNTRY WITH LOW LEVELS APPEARING DRIER ON THE PLAINS. TEMPERATURES BOTH DAYS REMAIN NEAR TO SLIGHTLY ABOVE AVERAGE. BY MONDAY...THE CORE OF THE SUBTROPICAL MOISTURE PLUME IS PROGGED TO SHIFT EVEN FARTHER WEST AWAY FROM THE FRONT RANGE WITH THE FLOW ALOFT BECOMING MORE EAST-SOUTHEASTERLY IN DIRECTION WITH THE UPPER HIGH OVER THE FOUR CORNERS FALLING APART. THEREFORE CHANCES FOR PRECIP ON MONDAY APPEAR MUCH LOWER ESPLY EAST OF THE MTNS. MODELS ALSO INDICATE SLIGHTLY COOLER TEMPERATURES ON MONDAY. NOT QUITE SURE WHY...POSSIBLY DUE TO GREAT CLOUD COVER. BY TUESDAY...THE HIGHEST SPECIFIC HUMIDITIES REMAIN WEST OF THE CONTINENTAL DIVIDE AS STEERING WINDS ALOFT TURN MORE SOUTHERLY DURING THE DAY. WILL WILL HELP TO INCREASE TEMPERATURES PARTICULARLY ON THE PLAINS. && .AVIATION...A WEAK DENVER CYCLONE HAS DEVELOPED OVER DIA EARLY THIS MORNING. AS MENTIONED ABV MOST OF THE SHORT RANGE MODELS WIPE IT OUT BY MIDDAY WITH RATHER STG SSE LOW LVL DEVELOPING. THE WRF IS THE ONLY MODEL WHICH KEEPS THE CYCLONE INTACT THRU THE AFTN WHICH LEADS TO VARYING WIND DIRECTIONS DEPENDING ON WHERE IT RESIDES. FOR NOW WILL KEEP WINDS SSE THRU THE AFTN. LATEST DATA SUGGEST TSTMS COULD DVLP AS EARLY AS 19Z AND THEN MOVE EAST OF THE AIRPORT BY 23Z. ITS ENTIRELY POSSIBLE IF THE DENVER CYCLONE GETS WIPED OUT THAT TSTMS MAY NOT AFFECT THE AIRPORT AT ALL AS THEY FOCUS TO THE EAST AND SOUTH HOWEVER WILL KEEP A PROB GROUP IN THE TAF. IF A STRONGER STORM WERE TO AFFECT THE AIRPORT THEN MAY SEE BRIEF MVFR CONDITIONS IN THE 19Z-23Z TIMEFRAME. BY THIS EVENING IT LOOKS LIKE THE TSTM THREAT WILL REMAIN TO THE EAST OF THE AIRPORT. RIGHT NOW THE MODELS SHOW EITHER A SLY OR SELY COMPONENT FOR WINDS WHICH BECOME MORE SSW AFTER 06Z. && .HYDROLOGY...SCATTERED THUNDERSTORMS WILL DEVELOP BY EARLY AFTN. POTENTIAL RAINFALL AMOUNTS IN THE BURN AREAS WILL BE IN THE 0.25 TO 0.50 RANGE. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....BAKER AVIATION...RPK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
126 AM MDT WED JUL 10 2013 .UPDATE... ISSUED AT 125 AM MDT WED JUL 10 2013 ADDED ISOLATED THUNDERSTORMS TO SOME EASTERN PLAINS GRIDS/ZONES AND ALSO ADJUSTED ADDITIONAL METEOROLOGICAL ELEMENTS TO REFLECT RECENT MET CONDITIONS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 253 PM MDT TUE JUL 9 2013 ...A FEW STRONG STORMS POSSIBLE TOMORROW... CURRENTLY...CONVECTION A BIT SLOW TO GET GOING...BUT SCT STORMS DEVELOPING OVER THE MTS...AND LINE OF CU ALONG AND N OF HGWY 50 IS STARTING TO SEE ISOLD CONVECTION DEVELOP. WILL CONTINUE TO SEE ISOLD STORMS THIS AFTERNOON AND EVENING OVER THE PLAINS...WITH STORMS MOVING TO THE S AND E. NOT EXPECTING A LOT OF RAIN WITH MOST OF THESE STORMS...ALTHOUGH A COUPLE OVER THE FAR SERN GRASSLANDS COULD BE A LITTLE MORE EFFICIENT RAIN PRODUCERS. THE HIGH RES WRF AND HRRR CONTINUE TO SHOW THE POTENTIAL FOR REDEVELOPMENT OF ISOLD SHOWERS AND STORMS OVER THE PALMER DVD AFTER 04Z TONIGHT...LINGERING INTO THE EARLY MORNING HOURS. AM SOMEWHAT SKEPTICAL AS THERE IS NO REAL UPSTREAM DISTURBANCE TO KICK THINGS OFF...BUT WILL MAINTAIN LOW/ISOLD POPS THROUGH TONIGHT FOR THAT AREA. TOMORROW...THE PRECIP/POPS FORECAST GETS TRICKIER. THE GFS HAS VERY LITTLE QPF OVER THE PLAINS TOMORROW...WHILE THE NAM HAS WIDESPREAD PRECIP...ESPECIALLY OVER THE ERN PORTIONS OF OUR CWA. HOWEVER...EVEN THE NAM HAS BACKED OFF ON THE EXTENT OF COOLER AIR MOVING INTO OUR AREA. LATEST MOS GUIDANCE FOR KPUB IN IN THE MID TO UPPER 90S. THE QUESTION IS TO WHAT EXTENT THE WEAK FRONTAL PUSH WILL MOVE INTO OUR AREA. OUTSIDE THE FRONT AND MODEST UPSLOPE...THERE IS NOT MUCH OF A TRIGGER IN THE FLOW ALOFT TO SUPPORT WIDESPREAD QPF. AM BEING A BIT CAUTIOUS WITH POPS TOMORROW...KEEPING CHANCE POPS OVER THE PLAINS IN THE AFTERNOON...BUT LATER SHIFTS MAY NEED TO DO SOME REDUCTIONS IF THE MODELS CONTINUE A TREND TOWARDS FEWER STORMS. THERE STILL SHOULD BE FAIRLY WIDESPREAD CONVECTION OVER THE ERN MTS...WITH LIGHT S TO SE FLOW ACROSS THE PLAINS IN THE AFTERNOON. DEWPOINTS SHOULD BE IN THE LOWER 50S TO POSSIBLY UPPER 50S CLOSER TO THE KS BORDER. THE LIGHT WINDS AND INCREASED MOISTURE SHOULD KEEP TEMPS FROM RISING AS HIGH AS MOS GUIDANCE SUGGESTS. DEPENDING ON HOW FAR THE FRONTAL BOUNDARY MAKES IT INTO SE CO...THERE ALSO COULD BE A MARGINAL THREAT OF SVR WX TOMORROW...ESPECIALLY E OF I-25 AND N OF HGWY 50 IN THE LATE AFTERNOON AND EARLY EVE. THE HIGHEST THREAT WILL BE OVER KIOWA COUNTY LATE IN THE DAY...WHERE BULK SHEARS WILL APPROACH 40 KTS OR SO AND MOISTURE WILL BE GREATEST. COULD SEE SOME HAIL FROM THE STRONGEST STORMS...ALONG WITH GUSTY WINDS AND BRIEF HEAVY RAINFALL. ROSE .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 253 PM MDT TUE JUL 9 2013 ...UPSWING IN THUNDERSTORMS WEDNESDAY EVENING...WITH MONSOON CONTINUING FOR THE NEXT SEVERAL DAYS... INTERACTION OF BOUNDARY MOVING THROUGH THE PLAINS AND MONSOON MOISTURE PROMISES AN UPSWING IN THUNDERSTORM ACTIVITY LASTING INTO WEDNESDAY EVENING. THEN...THURSDAY THROUGH SATURDAY...THE MONSOON REGROUPS OVER THE MOUNTAINS...MAINLY AFFECTING AREAS ALONG AND WEST OF I-25. HIGH PRESSURE CENTERS OVER EASTERN COLORADO AND WESTERN KANSAS DURING THIS TIME...DIRECTING THE FLOW OF MOISTURE INTO THOSE AREAS. BEGINNING SUNDAY...THE HIGH MAY SHIFT EAST FAR ENOUGH TO LET THE MONSOON SPILL OUT ONTO THE PLAINS...BRINGING AN UPSWING IN ACTIVITY TO THOSE AREAS. PRIMARY CONCERNS OVER THE NEXT SEVERAL DAYS WILL BE THE IMPACT OF HEAVY RAINS ON AREA BURN SCARS. IF HEAVY RAIN DEVELOPS OVER ANY OF THE SCARS...FLASH FLOODING AND DEBRIS FLOWS WILL BE POSSIBLE. OTHER CONCERNS THROUGH THE PERIOD WILL BE LIGHTNING...WIND GUSTS TO AROUND 55 MPH AND LOCAL SMALL HAIL. ITS STILL SEVERAL DAYS OFF...BUT THE GREATEST POTENTIAL FOR HEAVY RAINFALL WOULD APPEAR TO MOVE IN OVER THE WEEKEND AS UPPER HIGH PRESSURE SHIFTS OVER EASTERN COLORADO...ALLOWING MONSOONAL MOISTURE INFLUX INTO WESTERN COLORADO ON THE WEST SIDE OF THE HIGH. IN MANY CASES THE RAIN WILL BE BENEFICIAL...BUT THE RISK FOR FLASH FLOODING AND DEBRIS FLOWS IN AND AROUND AREA BURN SCARS WILL LIKELY INCREASE DURING THIS PERIOD. LW && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1059 PM MDT TUE JUL 9 2013 VFR CONDITIONS ARE GENERALLY EXPECTED AT KCOS...KPUB AND KALS FOR THE NEXT 24 HOURS. SOME ISOLD TSTMS ARE STILL POSSIBLE TONIGHT IN THE VCNTY OF KCOS. ON WEDNESDAY...MAINLY BETWEEN 18Z AND 02Z THE TERMINAL SITES WILL HAVE THE POTENTIAL FOR SHOWERS AND TSTMS IN THE VCNTY. THERE IS A SMALL CHANCE THAT MODERATE TO HEAVY RAIN COULD CAUSE MVFR CONDITIONS BRIEFLY. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1112 PM MDT TUE JUL 9 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 253 PM MDT TUE JUL 9 2013 ...A FEW STRONG STORMS POSSIBLE TOMORROW... CURRENTLY...CONVECTION A BIT SLOW TO GET GOING...BUT SCT STORMS DEVELOPING OVER THE MTS...AND LINE OF CU ALONG AND N OF HGWY 50 IS STARTING TO SEE ISOLD CONVECTION DEVELOP. WILL CONTINUE TO SEE ISOLD STORMS THIS AFTERNOON AND EVENING OVER THE PLAINS...WITH STORMS MOVING TO THE S AND E. NOT EXPECTING A LOT OF RAIN WITH MOST OF THESE STORMS...ALTHOUGH A COUPLE OVER THE FAR SERN GRASSLANDS COULD BE A LITTLE MORE EFFICIENT RAIN PRODUCERS. THE HIGH RES WRF AND HRRR CONTINUE TO SHOW THE POTENTIAL FOR REDEVELOPMENT OF ISOLD SHOWERS AND STORMS OVER THE PALMER DVD AFTER 04Z TONIGHT...LINGERING INTO THE EARLY MORNING HOURS. AM SOMEWHAT SKEPTICAL AS THERE IS NO REAL UPSTREAM DISTURBANCE TO KICK THINGS OFF...BUT WILL MAINTAIN LOW/ISOLD POPS THROUGH TONIGHT FOR THAT AREA. TOMORROW...THE PRECIP/POPS FORECAST GETS TRICKIER. THE GFS HAS VERY LITTLE QPF OVER THE PLAINS TOMORROW...WHILE THE NAM HAS WIDESPREAD PRECIP...ESPECIALLY OVER THE ERN PORTIONS OF OUR CWA. HOWEVER...EVEN THE NAM HAS BACKED OFF ON THE EXTENT OF COOLER AIR MOVING INTO OUR AREA. LATEST MOS GUIDANCE FOR KPUB IN IN THE MID TO UPPER 90S. THE QUESTION IS TO WHAT EXTENT THE WEAK FRONTAL PUSH WILL MOVE INTO OUR AREA. OUTSIDE THE FRONT AND MODEST UPSLOPE...THERE IS NOT MUCH OF A TRIGGER IN THE FLOW ALOFT TO SUPPORT WIDESPREAD QPF. AM BEING A BIT CAUTIOUS WITH POPS TOMORROW...KEEPING CHANCE POPS OVER THE PLAINS IN THE AFTERNOON...BUT LATER SHIFTS MAY NEED TO DO SOME REDUCTIONS IF THE MODELS CONTINUE A TREND TOWARDS FEWER STORMS. THERE STILL SHOULD BE FAIRLY WIDESPREAD CONVECTION OVER THE ERN MTS...WITH LIGHT S TO SE FLOW ACROSS THE PLAINS IN THE AFTERNOON. DEWPOINTS SHOULD BE IN THE LOWER 50S TO POSSIBLY UPPER 50S CLOSER TO THE KS BORDER. THE LIGHT WINDS AND INCREASED MOISTURE SHOULD KEEP TEMPS FROM RISING AS HIGH AS MOS GUIDANCE SUGGESTS. DEPENDING ON HOW FAR THE FRONTAL BOUNDARY MAKES IT INTO SE CO...THERE ALSO COULD BE A MARGINAL THREAT OF SVR WX TOMORROW...ESPECIALLY E OF I-25 AND N OF HGWY 50 IN THE LATE AFTERNOON AND EARLY EVE. THE HIGHEST THREAT WILL BE OVER KIOWA COUNTY LATE IN THE DAY...WHERE BULK SHEARS WILL APPROACH 40 KTS OR SO AND MOISTURE WILL BE GREATEST. COULD SEE SOME HAIL FROM THE STRONGEST STORMS...ALONG WITH GUSTY WINDS AND BRIEF HEAVY RAINFALL. ROSE .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 253 PM MDT TUE JUL 9 2013 ...UPSWING IN THUNDERSTORMS WEDNESDAY EVENING...WITH MONSOON CONTINUING FOR THE NEXT SEVERAL DAYS... INTERACTION OF BOUNDARY MOVING THROUGH THE PLAINS AND MONSOON MOISTURE PROMISES AN UPSWING IN THUNDERSTORM ACTIVITY LASTING INTO WEDNESDAY EVENING. THEN...THURSDAY THROUGH SATURDAY...THE MONSOON REGROUPS OVER THE MOUNTAINS...MAINLY AFFECTING AREAS ALONG AND WEST OF I-25. HIGH PRESSURE CENTERS OVER EASTERN COLORADO AND WESTERN KANSAS DURING THIS TIME...DIRECTING THE FLOW OF MOISTURE INTO THOSE AREAS. BEGINNING SUNDAY...THE HIGH MAY SHIFT EAST FAR ENOUGH TO LET THE MONSOON SPILL OUT ONTO THE PLAINS...BRINGING AN UPSWING IN ACTIVITY TO THOSE AREAS. PRIMARY CONCERNS OVER THE NEXT SEVERAL DAYS WILL BE THE IMPACT OF HEAVY RAINS ON AREA BURN SCARS. IF HEAVY RAIN DEVELOPS OVER ANY OF THE SCARS...FLASH FLOODING AND DEBRIS FLOWS WILL BE POSSIBLE. OTHER CONCERNS THROUGH THE PERIOD WILL BE LIGHTNING...WIND GUSTS TO AROUND 55 MPH AND LOCAL SMALL HAIL. ITS STILL SEVERAL DAYS OFF...BUT THE GREATEST POTENTIAL FOR HEAVY RAINFALL WOULD APPEAR TO MOVE IN OVER THE WEEKEND AS UPPER HIGH PRESSURE SHIFTS OVER EASTERN COLORADO...ALLOWING MONSOONAL MOISTURE INFLUX INTO WESTERN COLORADO ON THE WEST SIDE OF THE HIGH. IN MANY CASES THE RAIN WILL BE BENEFICIAL...BUT THE RISK FOR FLASH FLOODING AND DEBRIS FLOWS IN AND AROUND AREA BURN SCARS WILL LIKELY INCREASE DURING THIS PERIOD. LW && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1059 PM MDT TUE JUL 9 2013 VFR CONDITIONS ARE GENERALLY EXPECTED AT KCOS...KPUB AND KALS FOR THE NEXT 24 HOURS. SOME ISOLD TSTMS ARE STILL POSSIBLE TONIGHT IN THE VCNTY OF KCOS. ON WEDNESDAY...MAINLY BETWEEN 18Z AND 02Z THE TERMINAL SITES WILL HAVE THE POTENTIAL FOR SHOWERS AND TSTMS IN THE VCNTY. THERE IS A SMALL CHANCE THAT MODERATE TO HEAVY RAIN COULD CAUSE MVFR CONDITIONS BRIEFLY. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ROSE LONG TERM...LW AVIATION...28
AREA FORECAST DISCUSSION
NWS MIAMI FL
350 AM EDT WED JUL 10 2013 ...WATCHING DISORGANIZED TROPICAL STORM CHANTAL... .DISCUSSION...SATELLITE AND RADAR IMAGERY SHOWS CONVECTION EXTENDING FROM THE ATLANTIC WATERS OFF THE SE FLORIDA COAST EXTENDING ACROSS THE BAHAMAS INTO EASTERN CUBA. THIS IS ASSOCIATED WITH A MID-UPPER LEVEL LOW WHICH WILL TRACK WESTWARD TODAY. A SURFACE TROUGH IS ALIGNED ACROSS SOUTH FL AT THIS TIME AND WILL CONTINUE TO MOVE NW. THIS WILL PLACE SOUTH FL IN A MOIST SOUTHERLY FLOW TODAY-THURSDAY BEHIND THIS TROUGH AXIS. FOR THE NEAR TERM THROUGH EARLY THIS MORNING...EXPECT RAIN TO CONTINUE ALONG MUCH OF THE PALM BEACH COAST EXTENDING INTO NORTHEASTERN BROWARD COUNTY AS WELL. HAVE INCREASED POPS SUBSTANTIALLY ACROSS THESE AREAS FOR EARLY THIS MORNING BASED ON CURRENT ACTIVITY AND TRENDS. FOR TODAY...GFS MOS POPS HAVE DECREASED AND THE LATEST HRRR RUN SHOWS SOME ACTIVITY ALONG THE ATLANTIC COAST BEFORE FOCUSING MOSTLY INLAND IN THE AFTERNOON. HRRR DOES NOT HAVE A GOOD HANDLE ON CURRENT ACTIVITY BUT IT`S TREND SEEMS REASONABLE FOR TODAY, SO WILL FOLLOW THIS TREND, BUT WITH SLIGHTLY HIGHER POPS THAN GFS MOS...MORE IN LINE WITH NAM MOS. LOCALIZED HEAVY RAINFALL IS POSSIBLE TODAY-THURSDAY ALONG WITH THE POTENTIAL OF A FEW THUNDERSTORMS CONTAINING GUSTY WINDS. HOWEVER, INCREASING CLOUDINESS WILL ACT TO LIMIT INSTABILITY, SO MOST OF THE TSTORMS WILL BE ORDINARY. THE FORECAST FOR FRIDAY AND THIS WEEKEND WILL BE HIGHLY DEPENDENT ON THE TRACK AND INTENSITY OF TROPICAL STORM CHANTAL, OR WHAT`S LEFT OF IT. LET`S JUST SAY CHANTAL HAS SEEN BETTER DAYS. AS NHC STATED...REPORTS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT AND SATELLITE IMAGES INDICATE THAT CHANTAL IS LOSING ORGANIZATION. GIVEN THIS TREND AND LAND INTERACTION UPCOMING, CHANTAL WILL HAVE TO HANG ON TOUGH TO BE A SYSTEM NORTH OF THE GREATER ANTILLES. GIVEN THE HIGH UNCERTAINTY INVOLVED, THE FORECAST FOR THE LONGER TERM PERIOD WILL CONTINUE TO REFLECT CLIMO CONDITIONS. IN OTHER WORDS, A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY WITH LITTLE CHANGE IN TEMPS/HUMIDITY LEVELS. SUMMERTIME IN FLORIDA. && .MARINE...SE WINDS LESS THAN 15 KT WITH LOW SEAS WILL PREVAIL THROUGH THU. THE FORECAST FOR FRIDAY AND THIS WEEKEND IS ALL DEPENDENT ON TS CHANTAL. WINDS/SEAS COULD PICK UP QUITE A BIT OR REMAIN RATHER LOW...IT JUST ALL DEPENDS ON WHAT TRANSPIRES WITH CHANTAL. IT IS LOOKING POORLY ORGANIZED AT THE MOMENT. && .FIRE WEATHER...NO CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 76 88 78 / 50 30 50 30 FORT LAUDERDALE 87 79 89 79 / 50 30 50 40 MIAMI 88 77 89 78 / 50 30 50 40 NAPLES 87 73 90 75 / 50 30 50 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/GREGORIA AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
455 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWER ACTIVITY WAS PERSISTING IN THE WEST PART OF THE FORECAST AREA. THE ACTIVITY APPEARED TO BE MAINLY ASSOCIATED WITH AN H7 SHORTWAVE TROUGH. THE HRRR SHOWED SHOWERS CONTINUING IN THIS AREA FOR MUCH OF THE MORNING. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES MAY SUPPORT VERY HEAVY RAIN IN SOME AREAS. HEATING SHOULD HELP INCREASE SHOWER AND THUNDERSTORM COVERAGE THROUGHOUT THE FORECAST AREA DURING THE AFTERNOON WITH A CONTINUED THREAT OF VERY HEAVY RAIN. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGH GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... PERSISTENT SHOWERS CONTINUE OVER PORTIONS OF THE WESTERN MIDLANDS AND THE CSRA. HAVE MENTION VCSH/SHRA AGS/DNL UNTIL AROUND 11Z. THE POTENTIAL FOR EARLY MORNING FOG IS THE NEXT AREA OF CONCERN. MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH AROUND A 10 TO 15 KT LOW LEVEL JET. MVFR CONDITIONS POSSIBLE ACROSS THE AREA UNTIL 14Z. EXPECT CONDITIONS TO IMPROVE BY AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN LATER TODAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
414 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /THROUGH TODAY/... SHOWER ACTIVITY WAS PERSISTING IN THE WEST PART OF THE FORECAST AREA. THE ACTIVITY APPEARED TO BE MAINLY ASSOCIATED WITH AN H7 SHORTWAVE TROUGH. THE HRRR SHOWED SHOWERS CONTINUING IN THIS AREA FOR MUCH OF THE MORNING. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES MAY SUPPORT VERY HEAVY RAIN IN SOME AREAS. HEATING SHOULD HELP INCREASE SHOWER AND THUNDERSTORM COVERAGE THROUGHOUT THE FORECAST AREA DURING THE AFTERNOON WITH A CONTINUED THREAT OF VERY HEAVY RAIN. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGH GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... PERSISTENT SHOWERS WITH EMBEDDED THUNDERSTORMS CONTINUE OVER PORTIONS OF THE WESTERN MIDLANDS AND MUCH OF THE CSRA. HAVE MENTIONS VCTS/TSRA AT AGS/DNL UNTIL AROUND 07Z. THE POTENTIAL FOR LATE NIGHT/EARLY MORNING FOG IS THE NEXT AREA OF CONCERN. MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH AROUND A 10 TO 15 KT LOW LEVEL JET. CONTINUED TO INDICATE MVFR CONDITIONS DEVELOPING AT OGB/AGS/DNL AFTER 08Z. HOWEVER...CONDITIONS COULD BE EVEN LOWER...BUT WILL NOT GO IFR AT THOSE SITES AT THIS TIME AS CONFIDENCE NOT THAT HIGH. VISIBILITIES AT CAE/CUB ALREADY DROPPED TO 9SM...SO HINTED AT THEM GOING LOWER BUT KEPT THEM VFR FOR NOW. EXPECT CONDITIONS TO IMPROVE BY AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN ON WEDNESDAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
308 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /THROUGH TODAY/... SHOWER AND THUNDERSTORM ACTIVITY WAS PERSISTING IN THE WEST PART OF THE FORECAST AREA. THE ACTIVITY APPEARED TO BE MAINLY ASSOCIATED WITH AN H7 SHORTWAVE TROUGH. THE HRRR SHOWED SHOWERS CONTINUING IN THIS AREA FOR MUCH OF THE MORNING. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES WILL SUPPORT VERY HEAVY RAIN IN SOME AREAS. HEATING SHOULD HELP INCREASE SHOWER AND THUNDERSTORM COVERAGE IN THE REST OF THE FORECAST AREA DURING THE AFTERNOON WITH A CONTINUED THREAT OF VERY HEAVY RAIN. WE HAVE LEANED TOWARD THE HIGH GUIDANCE POPS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGH GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. THERE ARE DIFFERENCES LATER IN THE PERIOD WITH THE GFS SHOWING ANOTHER UPPER LOW OVER THE FORECAST AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... PERSISTENT SHOWERS WITH EMBEDDED THUNDERSTORMS CONTINUE OVER PORTIONS OF THE WESTERN MIDLANDS AND MUCH OF THE CSRA. HAVE MENTIONS VCTS/TSRA AT AGS/DNL UNTIL AROUND 07Z. THE POTENTIAL FOR LATE NIGHT/EARLY MORNING FOG IS THE NEXT AREA OF CONCERN. MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH AROUND A 10 TO 15 KT LOW LEVEL JET. CONTINUED TO INDICATE MVFR CONDITIONS DEVELOPING AT OGB/AGS/DNL AFTER 08Z. HOWEVER...CONDITIONS COULD BE EVEN LOWER...BUT WILL NOT GO IFR AT THOSE SITES AT THIS TIME AS CONFIDENCE NOT THAT HIGH. VISIBILITIES AT CAE/CUB ALREADY DROPPED TO 9SM...SO HINTED AT THEM GOING LOWER BUT KEPT THEM VFR FOR NOW. EXPECT CONDITIONS TO IMPROVE BY AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN ON WEDNESDAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
424 AM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * BRIEF PERIOD OF VFR CEILINGS AND VIS EARLY THIS MORNING. * ISOLATED SHRA ACROSS THE AREA EARLY THIS MORNING...BUT WITH A LOW CHANCE FOR ANY PRECIP TO MOVE OVER THE TERMINALS. * SOUTHWEST WINDS SHIFTING TO THE WEST/NORTHWEST WITH FROPA EARLY THIS MORNING...WITH LAKE INFLUENCE TURNING THE WINDS NORTHEAST IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING...AND IS GENERALLY EXPECTED TO REMAIN THIS WAY THROUGHOUT THE FORECAST PERIOD. SURFACE TROUGH AND FRONT STILL REMAINING JUST TO THE WEST OF THE TERMINALS BUT IS EXPECTED TO CONTINUE SHIFTING EAST ACROSS NORTHERN ILLINOIS THIS MORNING. LATEST SATELLITE IMAGERY IS DEPICTING SOME VFR CEILINGS DEVELOPING JUST AHEAD OF THIS FRONT AND DO FEEL THAT A BRIEF PERIOD OF VFR CEILINGS IS POSSIBLE BEFORE THIS FROPA. WITH A VERY WARM AND MOIST AIRMASS STILL IN PLACE...SCATTERED FOG DEVELOPMENT IS ALSO POSSIBLE OUT AHEAD OF THIS FRONT. PRECIP DEVELOPMENT DOES REMAIN POSSIBLE IN THE NEAR TERM...BUT IF PRECIP DOES DEVELOP THE BULK OF IT SHOULD REMAIN JUST SOUTH OF THE TERMINALS. SOUTHWEST WINDS WILL VEER TO THE WEST AND THEN THE NORTHWEST WITH FROPA THIS MORNING...AND THEN INCREASE WITH SOME GUSTS TO THE UPPER TEENS POSSIBLE BY MID/LATE MORNING. WITH THE WIND DIRECTION ORIENTED OUT OF THE NORTH NORTHWEST BY MID DAY...IT WOULDNT TAKE MUCH FOR THE WINDS TO FLOP OVER TO THE NORTHEAST WITH THE LAKE INFLUENCE. SO HAVE INTRODUCED A WIND SHIFT TO THE NORTHEAST BY 20Z THIS AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS THIS MORNING AS IT COULD EASILY BE AN HOUR TO EARLIER THAN 20Z. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE WITH CEILING/VIS TRENDS. * HIGH CONFIDENCE WITH PRECIP TRENDS EARLY THIS MORNING. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THU THROUGH SUN...VFR. NO SIG WX. MON...VFR. SLGT CHANCE TSRA TRS && .MARINE... 416 AM CDT AS A TROUGH OF LOW PRESSURE AND ASSOCIATED COLD FRONT BEGIN TO PUSH EAST ACROSS THE NORTHERN PORTIONS OF THE LAKE THIS MORNING...A FAIRLY TIGHT PRESSURE GRADIENT HAS HELPED SOUTHWEST WINDS TO INCREASE TO 15 TO 25 KT OVER THE NORTHERN PORTIONS OF THE LAKE WHILE AREAS FURTHER SOUTH ARE OBSERVING SPEEDS OF 10 TO 20 KT. AS THIS TROUGH/FRONT CONTINUE SOUTHEAST DOWN THE LAKE THIS MORNING...EXPECT THESE SOUTHWEST WINDS TO SHIFT TO THE WEST/NORTHWEST AND THEN HOLD ONTO A NORTHWEST DIRECTION FOR THE REMAINDER OF THE DAY INTO TONIGHT. EXPECT LIGHT NORTHERLY FLOW OVER THE LAKE FOR MOST OF THURSDAY AS HIGH PRESSURE SLOWLY SHIFTS EAST TOWARDS THE CENTRAL GREAT LAKES. BY FRIDAY WINDS TURN BACK TO A SOUTHERLY DIRECTION...AS THIS HIGH SETTLES OVER THE EASTERN GREAT LAKES INTO THE WEEKEND. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
403 AM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * BRIEF PERIOD OF VFR CEILINGS AND VIS EARLY THIS MORNING. * ISOLATED SHRA ACROSS THE AREA EARLY THIS MORNING...BUT WITH A LOW CHANCE FOR ANY PRECIP TO MOVE OVER THE TERMINALS. * SOUTHWEST WINDS SHIFTING TO THE WEST/NORTHWEST WITH FROPA EARLY THIS MORNING...WITH LAKE INFLUENCE TURNING THE WINDS NORTHEAST IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING...AND IS GENERALLY EXPECTED TO REMAIN THIS WAY THROUGHOUT THE FORECAST PERIOD. SURFACE TROUGH AND FRONT STILL REMAINING JUST TO THE WEST OF THE TERMINALS BUT IS EXPECTED TO CONTINUE SHIFTING EAST ACROSS NORTHERN ILLINOIS THIS MORNING. LATEST SATELLITE IMAGERY IS DEPICTING SOME VFR CEILINGS DEVELOPING JUST AHEAD OF THIS FRONT AND DO FEEL THAT A BRIEF PERIOD OF VFR CEILINGS IS POSSIBLE BEFORE THIS FROPA. WITH A VERY WARM AND MOIST AIRMASS STILL IN PLACE...SCATTERED FOG DEVELOPMENT IS ALSO POSSIBLE OUT AHEAD OF THIS FRONT. PRECIP DEVELOPMENT DOES REMAIN POSSIBLE IN THE NEAR TERM...BUT IF PRECIP DOES DEVELOP THE BULK OF IT SHOULD REMAIN JUST SOUTH OF THE TERMINALS. SOUTHWEST WINDS WILL VEER TO THE WEST AND THEN THE NORTHWEST WITH FROPA THIS MORNING...AND THEN INCREASE WITH SOME GUSTS TO THE UPPER TEENS POSSIBLE BY MID/LATE MORNING. WITH THE WIND DIRECTION ORIENTED OUT OF THE NORTH NORTHWEST BY MID DAY...IT WOULDNT TAKE MUCH FOR THE WINDS TO FLOP OVER TO THE NORTHEAST WITH THE LAKE INFLUENCE. SO HAVE INTRODUCED A WIND SHIFT TO THE NORTHEAST BY 20Z THIS AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS THIS MORNING AS IT COULD EASILY BE AN HOUR TO EARLIER THAN 20Z. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE WITH CEILING/VIS TRENDS. * HIGH CONFIDENCE WITH PRECIP TRENDS EARLY THIS MORNING. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THU THROUGH SUN...VFR. NO SIG WX. MON...VFR. SLGT CHANCE TSRA TRS && .MARINE... 250 PM CDT THE WEAK HIGH AND LOW ARE OVER SOUTHERN MI AND WILL CONTINUE TO DISSIPATE. A BROAD TROUGH OF LOW PRESSURE EXTENDS FROM NORTHERN ONTARIO THROUGH THE CENTRAL PLAINS AND IT WILL SLIDE OVER THE LAKE TONIGHT AND ITS COLD FRONT WILL ALSO SLIDE OVER THE LAKE LATE TONIGHT/EARLY WED MORNING. FOG HAS DISSIPATED OVER THE SOUTHERN HALF OF THE LAKE BUT IS HOLDING STRONG OVER THE NORTHERN HALF. THINKING THE FOG WILL DISSIPATE AS SHOWERS MOVE OVER THE NORTHERN HALF OF THE LAKE...BUT DENSE FOG MAY STICK AROUND OVER THE NORTH HALF OF THE LAKE UNTIL THE FRONT MOVES THROUGH EARLY WED MORNING. FOR NOW EXTENDED THE DENSE FOG ADVISORY THROUGH 9PM TONIGHT FOR AREAS NORTH OF A LINE CONNECTING SHEBOYGAN WI TO PENTWATER MI. WINDS TURN W TO NW BEHIND THE FRONT AND THEN WEAKEN/BECOME MORE VARIABLE LATE ON THURSDAY AS THE HIGH MOVES OVER THE LAKE. THE HIGH CONTINUES TO MOVE EAST OF THE LAKE ON FRIDAY WITH SE TO S WINDS EXPECTED ACROSS THE LAKE. WHILE THE HIGHS CENTER MOVES OVER NEW ENGLAND FRIDAY NIGHT/SATURDAY MORNING...S WINDS ARE EXPECTED THROUGH THE REST OF THE FORECAST PERIOD. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
308 AM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * BRIEF PERIOD OF VFR CEILINGS AND VIS EARLY THIS MORNING. * ISOLATED SHRA ACROSS THE AREA EARLY THIS MORNING...BUT WITH A LOW CHANCE FOR ANY PRECIP TO MOVE OVER THE TERMINALS. * SOUTHWEST WINDS SHIFTING TO THE WEST/NORTHWEST WITH FROPA EARLY THIS MORNING...WITH LAKE INFLUENCE TURNING THE WINDS NORTHEAST IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING...AND IS GENERALLY EXPECTED TO REMAIN THIS WAY THROUGHOUT THE FORECAST PERIOD. SURFACE TROUGH AND FRONT STILL REMAINING JUST TO THE WEST OF THE TERMINALS BUT IS EXPECTED TO CONTINUE SHIFTING EAST ACROSS NORTHERN ILLINOIS THIS MORNING. LATEST SATELLITE IMAGERY IS DEPICTING SOME VFR CEILINGS DEVELOPING JUST AHEAD OF THIS FRONT AND DO FEEL THAT A BRIEF PERIOD OF VFR CEILINGS IS POSSIBLE BEFORE THIS FROPA. WITH A VERY WARM AND MOIST AIRMASS STILL IN PLACE...SCATTERED FOG DEVELOPMENT IS ALSO POSSIBLE OUT AHEAD OF THIS FRONT. PRECIP DEVELOPMENT DOES REMAIN POSSIBLE IN THE NEAR TERM...BUT IF PRECIP DOES DEVELOP THE BULK OF IT SHOULD REMAIN JUST SOUTH OF THE TERMINALS. SOUTHWEST WINDS WILL VEER TO THE WEST AND THEN THE NORTHWEST WITH FROPA THIS MORNING...AND THEN INCREASE WITH SOME GUSTS TO THE UPPER TEENS POSSIBLE BY MID/LATE MORNING. WITH THE WIND DIRECTION ORIENTED OUT OF THE NORTH NORTHWEST BY MID DAY...IT WOULDNT TAKE MUCH FOR THE WINDS TO FLOP OVER TO THE NORTHEAST WITH THE LAKE INFLUENCE. SO HAVE INTRODUCED A WIND SHIFT TO THE NORTHEAST BY 20Z THIS AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS THIS MORNING AS IT COULD EASILY BE AN HOUR TO EARLIER THAN 20Z. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE WITH CEILING/VIS TRENDS. * HIGH CONFIDENCE WITH PRECIP TRENDS EARLY THIS MORNING. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THU THROUGH SUN...VFR. NO SIG WX. MON...VFR. SLGT CHANCE TSRA TRS && .MARINE... 250 PM CDT THE WEAK HIGH AND LOW ARE OVER SOUTHERN MI AND WILL CONTINUE TO DISSIPATE. A BROAD TROUGH OF LOW PRESSURE EXTENDS FROM NORTHERN ONTARIO THROUGH THE CENTRAL PLAINS AND IT WILL SLIDE OVER THE LAKE TONIGHT AND ITS COLD FRONT WILL ALSO SLIDE OVER THE LAKE LATE TONIGHT/EARLY WED MORNING. FOG HAS DISSIPATED OVER THE SOUTHERN HALF OF THE LAKE BUT IS HOLDING STRONG OVER THE NORTHERN HALF. THINKING THE FOG WILL DISSIPATE AS SHOWERS MOVE OVER THE NORTHERN HALF OF THE LAKE...BUT DENSE FOG MAY STICK AROUND OVER THE NORTH HALF OF THE LAKE UNTIL THE FRONT MOVES THROUGH EARLY WED MORNING. FOR NOW EXTENDED THE DENSE FOG ADVISORY THROUGH 9PM TONIGHT FOR AREAS NORTH OF A LINE CONNECTING SHEBOYGAN WI TO PENTWATER MI. WINDS TURN W TO NW BEHIND THE FRONT AND THEN WEAKEN/BECOME MORE VARIABLE LATE ON THURSDAY AS THE HIGH MOVES OVER THE LAKE. THE HIGH CONTINUES TO MOVE EAST OF THE LAKE ON FRIDAY WITH SE TO S WINDS EXPECTED ACROSS THE LAKE. WHILE THE HIGHS CENTER MOVES OVER NEW ENGLAND FRIDAY NIGHT/SATURDAY MORNING...S WINDS ARE EXPECTED THROUGH THE REST OF THE FORECAST PERIOD. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
204 AM CDT WED JUL 10 2013 .DISCUSSION... ISSUED 204 AM CDT WED JUL 10 2013 ONE MORE DAY OF POTENTIAL STORM CHANCES...BEFORE AN EXTENDED PERIOD OF DRY WEATHER ARRIVES ACROSS CENTRAL ILLINOIS. SHORT TERM...TODAY THROUGH FRIDAY 06Z/1AM SURFACE MAP SHOWS LOW PRESSURE OVER LAKE SUPERIOR...WITH TRAILING COLD FRONT EXTENDING SOUTHWESTWARD ACROSS EASTERN IOWA INTO FAR NORTHERN KANSAS. ALOFT...VIGOROUS SHORT-WAVE IS EVIDENT ON WATER VAPOR IMAGERY OVER MINNESOTA...WHILE A WEAKER WAVE IS NOTED OVER NEBRASKA/KANSAS. CONVECTION DURING THE OVERNIGHT HOURS HAS BEEN TIED TO THE SOUTHERN WAVE IN CONJUNCTION WITH A 30KT LLJ FLOWING NORTHEASTWARD FROM THE SOUTHERN PLAINS. RESULTING CONVECTIVE COMPLEX CURRENTLY OVER NORTHEAST KANSAS IS EXPECTED TO TRACK E/SE INTO MISSOURI DURING THE PRE-DAWN HOURS...STAYING OFF TO THE W/SW OF CENTRAL ILLINOIS. MEANWHILE...WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP FURTHER NORTHEAST INTO CENTRAL ILLINOIS WITHIN THE WEAK LLJ AXIS. LATEST RADAR IMAGERY SHOWS CONVECTION BEGINNING TO DEVELOP ACROSS CENTRAL MISSOURI INTO SOUTHWEST ILLINOIS...AND EXPECT THIS TREND TO CONTINUE INTO THE EARLY MORNING HOURS. MODELS HAVE BEEN HANDLING CONVECTIVE DEVELOPMENT/EVOLUTION POORLY FOR THE PAST SEVERAL DAYS...AND THE 00Z JUL 10 SUITE IS NO EXCEPTION. WILL THEREFORE RELY MAINLY ON LATEST SATELLITE/RADAR DATA AND CONSISTENCY FOR THE IMMEDIATE SHORT-TERM FORECAST. AS SUCH...THINK SCATTERED SHOWERS/STORMS WILL CONTINUE TO DEVELOP NORTHEASTWARD ACROSS AT LEAST THE SOUTHERN TWO-THIRDS OF THE KILX CWA THIS MORNING. AS COLD FRONT SAGS SOUTHWARD TO NEAR THE I-72 CORRIDOR BY MIDDAY...RAIN THREAT WILL ESSENTIALLY COME TO AN END ALONG AND NORTH OF A RUSHVILLE TO BLOOMINGTON-NORMAL LINE THIS AFTERNOON. FURTHER SOUTH...SEVERAL HIGH-RES MODELS ARE HINTING THAT AT LEAST A BROKEN LINE OF CONVECTION WILL DEVELOP IN THE HIGHLY UNSTABLE AIRMASS ALONG/SOUTH OF THE BOUNDARY. GIVEN HIGH CAPE VALUES OF AROUND 4000J/KG AND SLIGHT COOLING ALOFT ASSOCIATED WITH MINNESOTA SHORT-WAVE TRACKING INTO THE GREAT LAKES...THINK THIS IS A REASONABLE SOLUTION. AS A RESULT...WILL CARRY CHANCE POPS ACROSS THE BOARD DURING THE MORNING HOURS...THEN WILL FOCUS LIKELY POPS ALONG/SOUTH OF A PARIS TO TAYLORVILLE LINE THIS AFTERNOON. WILL BE ANOTHER WARM AND HUMID DAY...AS COOLER/DRIER AIRMASS WILL INITIALLY BE RATHER SLOW TO ARRIVE BEHIND FRONT. HIGHS WILL RANGE FROM THE MIDDLE 80S ACROSS THE NORTH...TO THE LOWER 90S SOUTH OF I-70. MOST MODELS DROP FRONT AND ANY LINGERING PRECIP CHANCES SOUTH OF THE CWA BY EVENING...HOWEVER 00Z NAM NOW FEATURES A WEAK WAVE ALONG THE BOUNDARY THAT BRIEFLY IMPEDES ITS SOUTHWARD PROGRESS. SINCE THIS IS THE FIRST RUN THE WAVE HAS APPEARED ON...AND THERE DOES NOT SEEM TO BE ANY SUPPORTING UPPER SUPPORT FOR IT...WILL GENERALLY DISREGARD THIS SOLUTION. WILL HOWEVER HANG ON TO JUST A SLIGHT CHANCE POP SOUTH OF I-70 INTO THE EVENING...IN CASE AFTERNOON STORMS HAVE NOT DROPPED SOUTH/EAST OF THE CWA BY 00Z. HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES FOR THURSDAY AND FRIDAY...PROVIDING A COOL/DRY NORTHEASTERLY FLOW. HIGH TEMPERATURES WILL ONLY REACH THE LOWER TO MIDDLE 80S BOTH DAYS...WHILE OVERNIGHT LOWS DROP INTO THE UPPER 50S AND LOWER 60S. IN ADDITION...RELATIVE HUMIDITY VALUES WILL BE CONSIDERABLY LOWER. LONG TERM...SATURDAY THROUGH TUESDAY GREAT LAKES UPPER TROUGH WILL SHIFT INTO NEW ENGLAND OVER THE WEEKEND...WHILE UPPER RIDGE BUILDS INTO THE MIDWEST. WHILE SURFACE RIDGING WILL MAINTAIN AN E/SE LOW-LEVEL FLOW THROUGH SUNDAY...RISING UPPER HEIGHTS AND FULL JULY SUNSHINE WILL QUICKLY MODIFY THE AIRMASS. AS A RESULT...HIGH TEMPERATURES WILL CLIMB BACK INTO THE UPPER 80S BY SUNDAY. AS SURFACE RIDGE SHIFTS FURTHER AWAY...A DEVELOPING SOUTHERLY FLOW WILL BRING THE HUMIDITY BACK INTO THE PICTURE EARLY NEXT WEEK. WITH HIGH TEMPS REACHING THE 90 DEGREE MARK AND DEWPOINTS RISING INTO THE 70S...HEAT INDEX VALUES WILL LIKELY APPROACH 100 DEGREES AGAIN BY MONDAY AND TUESDAY. RAIN CHANCES WILL BE SLIM TO NONE THROUGH THE EXTENDED AND BEYOND...AS E/W ORIENTED UPPER RIDGE ACROSS THE MIDWEST WILL KEEP MAIN STORM TRACK AND BEST CHANCES FOR PRECIP WELL TO THE NORTH AND SOUTH OF CENTRAL ILLINOIS. BARNES && .AVIATION... ISSUED 1145 PM CDT TUE JUL 9 2013 DELAYED ONSET OF STORMS CONTINUES...AND THE 02Z HRRR CONTINUES TO SHOW STORMS HOLDING OFF UNTIL AFTER 11Z-12Z FOR PIA...WITH A LINE OF STORMS FROM SPI TO CMI IN PLACE AROUND 16Z-17Z. WE PUSHED THE START OF ANY VCTS LATER IN THE TAF PERIOD TO MATCH THAT PROGRESSION. STILL...THE STORMS WILL BE OF A SCATTERED COVERAGE...SO ANY SHORT PERIOD IFR/LIFR DURING ANY THUNDERSTORMS WAS LEFT OUT. EVEN MVFR WILL BE LIMITED TO ANY STORM PATHS ACROSS THE AIRPORTS. WE WILL CONTINUE THE VFR PREVAILING...UNTIL ANY STORMS DEVELOP LATE TONIGHT OR WED MORNING. WINDS WILL START OUR SOUTHWESTERLY...THEN VEER TO THE NW AFTER FROPA. BY WED AFTERNOON...TURBULENT MIXING WILL PUSH SUSTAINED WINDS IN THE 10-15KT RANGE. WINDS WILL SUBSIDE BY SUNSET...BUT REMAIN NORTH THROUGH 06Z WED NIGHT. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1257 AM CDT WED JUL 10 2013 .DISCUSSION... 900 PM CDT NOT MUCH CHANGE TO PREVIOUS THINKING. VERY MOIST AND UNSTABLE AIRMASS STILL IN PLACE BUT WEAKLY CAPPED. WITH SHORT WAVE OVER THE IL/IN BORDER DEPARTING TO THE EAST THIS EVENING...LITTLE SUPPORT FOR ORGANIZED CONVECTION THIS EVENING. 0-6KM BULK SHEAR AROUND 30 KT SHOULD INCREASE SOME OVERNIGHT AS STRONG WAVE OVER MN CONTINUES TO DIG INTO THE GREAT LAKES. MAY STILL GET SOME SCATTERED CONVECTION WITH COLD FRONT LATER TONIGHT. A COUPLE CELLS SHOWING UP OVER NORTHEAST IA ATTM. HRRR AND OTHER SHORT RANGE GUIDANCE STILL SUGGESTING SOME SCATTERED ACTIVITY OVERNIGHT. BUT LOOKS LIKE MORE ORGANIZED STORMS OVER NE/KS WILL DRIVE E ACROSS MO INTO CENTRAL IL BY MORNING. WILL MAINTAIN LOW END POPS OVERNIGHT. ALLSOPP //PREV DISCUSSION... 250 PM CDT SHORT TERM...THIS EVENING THROUGH FRIDAY... SEVERE WEATHER/HEAVY RAINFALL POTENTIAL APPEARS TO BE DIMINISHING SIGNIFICANTLY ACROSS THE FORECAST AREA THROUGH TONIGHT. PERSISTENT ELEVATED CONVECTION AND ASSOCIATED CLOUD SHIELD HAS LIMITED STRONG DESTABILIZATION ACROSS MUCH OF THE CWA INTO THIS AFTERNOON. THIS...ALONG WITH A LACK OF STRONGER MID-LEVEL WINDS/DEEP SHEAR (WHICH WAS LAGGING SHORT WAVE FORCING ACROSS THE REGION) APPEARS TO HAVE DECREASED OUR POTENTIAL FOR STRONG/SEVERE THUNDERSTORMS ACROSS MUCH OF THE CWA THROUGH TONIGHT. AFTERNOON SURFACE ANALYSIS DEPICTS LOW PRESSURE OVER NORTHWEST WI WITH A WARM FRONTAL BOUNDARY EXTENDING SOUTHEAST TO SOUTHEAST WI/SOUTHERN LAKE MICHIGAN. A COLD FRONT TRAILED FROM THE LOW TO NORTHWESTERN IA AND CENTRAL KS. THE WARM SECTOR ACROSS CENTRAL IL WAS CHARACTERIZED BY TEMPS NEAR 90 AND DEW POINT TEMPS IN THE LOW-MID 70S...WHILE PERSISTENT CLOUDS/PRECIP HAVE HELD TEMPS INTO THE MID 70S-LOWER 80S ACROSS MUCH OF THE WFO LOT CWA. OUR COOLER BOUNDARY LAYER IS CLEARLY SHOWN IN AMDAR AIRCRAFT ASCENT SOUNDINGS FROM KMDW THIS AFTERNOON...AND SUPPORT SPC/RAP MESOANALYSIS DATA WHICH INDICATES A FAIRLY SUBSTANTIAL CAP IN PLACE ACROSS NORTHERN IL FOR SURFACE/NEAR SURFACE BASED PARCELS. AFTERNOON GOES SATELLITE WATER VAPOR IMAGERY INDICATES A SHORT-WAVE TROUGH APPROACHING THE MISSISSIPPI RIVER ACROSS MN/WI AND EASTERN IA AT THIS HOUR...WITH A VORT/MCV NOTED OVER SOUTHEAST IA. THIS SHOULD TRACK ACROSS THE WFO LOT CWA BETWEEN ROUGHLY 21-01Z AND MAY SERVE AS A TRIGGER FOR AN INCREASE IN CONVECTION ESPECIALLY SOUTH OF I-80...WHICH RAP/HRRR RUNS HAVE BEEN DEPICTING. APPROACH OF MODEST MID-LEVEL SPEED MAX AROUND 35 KT WOULD SUPPORT AN INCREASE IN EFFECTIVE BULK SHEAR VALUES TO 30-35 KT...WHICH MAY HELP ANY DEVELOPING CONVECTION BECOME BETTER ORGANIZED AND PERHAPS PRESENT A DAMAGING WIND THREAT ACROSS THE SOUTHERN CWA THROUGH THE LATE AFTERNOON. MID-LEVEL FEATURE LOOKS TO MOVE EAST OF THE CWA BY 01Z OR SO...WITH THUNDERSTORM THREAT SHIFTING LARGELY OFF TO THE EAST/SOUTH OF THE AREA BEYOND THAT TIME. ANY STORMS THAT DO DEVELOP WILL CONTINUE TO PRESENT A HEAVY RAINFALL THREAT...WITH PWATS RIGHT AROUND 2 INCHES. STRONGER SHORT WAVE TROUGH AND JET MAX FEATURE OVER THE NORTHERN PLAINS THIS AFTERNOON WILL PROPAGATE EAST-SOUTHEAST INTO THE WESTERN GREAT LAKES REGION BY WEDNESDAY MORNING...WITH MAIN AREA OF SURFACE LOW PRESSURE DEEPENING AND LIFTING ACROSS THE NORTHERN LAKES OVERNIGHT AND TRAILING THE AFOREMENTIONED COLD FRONT INTO NORTHERN IL LATE. WHILE SOME POTENTIAL FOR ADDITIONAL SHOWERS/THUNDERSTORMS CANT BE RULED OUT OVERNIGHT (POTENTIAL FOR DEVELOPMENT LATE THIS AFTERNOON MOST LIKELY OVER SOUTHEAST MN/WESTERN WI) UPSTREAM SOUNDINGS FROM ABR/OAX INDICATE SUBSTANTIAL DRY AIR ALOFT BEHIND LEAD SHORT WAVE OVER EASTERN IA...AND GUIDANCE HAS TRENDED MUCH DRIER AFTER INITIAL WAVE PASSES EARLY THIS EVENING. THUS HAVE ELECTED TO MAINTAIN SOME SLIGHT CHANCE POPS OVERNIGHT WITH ARRIVAL OF SURFACE FRONT AND LARGE SCALE FORCING FROM DIGGING NORTHERN PLAINS WAVE...THOUGH SUSPECT THAT THE POTENTIAL FOR STRONG THUNDERSTORMS AND ANY SEVERE/HEAVY RAIN THREAT WILL BE LIMITED TO THE LATE AFTERNOON AND EARLY EVENING HOURS. COLD FRONT THEN CONTINUES TO PUSH SOUTHEAST ACROSS THE FORECAST AREA WEDNESDAY MORNING...ENDING PRECIP THREAT FROM THE NORTHWEST. AFTER ANOTHER WARM/MUGGY NIGHT AHEAD OF THE FRONT TONIGHT...SOMEWHAT COOLER AND DRIER AIR WILL FILTER INTO THE AREA WEDNESDAY. NORTHERN COUNTIES WILL LIKELY SEE HIGHS IN THE UPPER 70S/LOW 80S WHILE THE SOUTH REMAINS A LITTLE MUGGIER IN THE MID/UPPER 80S. FULL EFFECTS OF THE CHANGE IN AIR MASS WILL BE FELT THURSDAY AND FRIDAY...WITH PLENTIFUL SUNSHINE AND UPPER 70S/LOW 80S CWA-WIDE...AND MID 70S ALONG THE LAKE WITH MODEST ONSHORE FLOW. RATZER EXTENDED...FRIDAY NIGHT THROUGH MONDAY... ALOFT THE LARGE HIGH OVER THE CENTRAL PLAINS STRENGTHENS AND GROWS IN SIZE ACROSS THE MID MISSISSIPPI RIVER VALLEY. AT THE SURFACE HIGH PRESSURE OVER THE EASTERN GREAT LAKES SHIFTS EAST OVER NEW ENGLAND. HOWEVER THE WESTERN EDGE OF THE HIGH REMAINS OVER THE REGION KEEPING THE ZONAL FLOW AND A SERIES OF SHORTWAVE TROUGHS AND WEAK LOWS TO OUR NORTH. THAT BEING SAID...IF THE HIGH SHIFTS SOUTH THE SYSTEMS COULD EASILY MOVE THROUGH NORTHERN IL AND NW INDIANA. AS IT STANDS NOW THE WEEKEND STARTS DRY WITH SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY NIGHT/MONDAY MAINLY ALONG THE IL/WI STATE LINE AS A SURFACE TROUGH PASSES THROUGH THE REGION. HIGH PRESSURE REESTABLISHES ITSELF ACROSS NORTHERN IL MONDAY NIGHT WITH DRY CONDITIONS EXPECTED FOR THE BEGINNING OF THE WORK WEEK. CONTINUED HOT AND MUGGY CONDITIONS ARE EXPECTED WITH TEMPS IN THE MID TO UPPER 80S AND DEWPOINTS IN THE 60S-70S THROUGHOUT THE EXTENDED. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * BRIEF PERIOD OF VFR CEILINGS AND VIS EARLY THIS MORNING. * ISOLATED SHRA ACROSS THE AREA EARLY THIS MORNING...BUT WITH A LOW CHANCE FOR ANY PRECIP TO MOVE OVER THE TERMINALS. * SOUTHWEST WINDS SHIFTING TO THE WEST/NORTHWEST WITH FROPA EARLY THIS MORNING...WITH LAKE INFLUENCE TURNING THE WINDS NORTHEAST IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 06Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING...AND IS GENERALLY EXPECTED TO REMAIN THIS WAY THROUGHOUT THE FORECAST PERIOD. SURFACE TROUGH AND FRONT STILL REMAINING JUST TO THE WEST OF THE TERMINALS BUT IS EXPECTED TO CONTINUE SHIFTING EAST ACROSS NORTHERN ILLINOIS THIS MORNING. LATEST SATELLITE IMAGERY IS DEPICTING SOME VFR CEILINGS DEVELOPING JUST AHEAD OF THIS FRONT AND DO FEEL THAT A BRIEF PERIOD OF VFR CEILINGS IS POSSIBLE BEFORE THIS FROPA. WITH A VERY WARM AND MOIST AIRMASS STILL IN PLACE...SCATTERED FOG DEVELOPMENT IS ALSO POSSIBLE OUT AHEAD OF THIS FRONT. PRECIP DEVELOPMENT DOES REMAIN POSSIBLE IN THE NEAR TERM...BUT IF PRECIP DOES DEVELOP THE BULK OF IT SHOULD REMAIN JUST SOUTH OF THE TERMINALS. SOUTHWEST WINDS WILL VEER TO THE WEST AND THEN THE NORTHWEST WITH FROPA THIS MORNING...AND THEN INCREASE WITH SOME GUSTS TO THE UPPER TEENS POSSIBLE BY MID/LATE MORNING. WITH THE WIND DIRECTION ORIENTED OUT OF THE NORTH NORTHWEST BY MID DAY...IT WOULDNT TAKE MUCH FOR THE WINDS TO FLOP OVER TO THE NORTHEAST WITH THE LAKE INFLUENCE. SO HAVE INTRODUCED A WIND SHIFT TO THE NORTHEAST BY 20Z THIS AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS THIS MORNING AS IT COULD EASILY BE AN HOUR TO EARLIER THAN 20Z. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE WITH CEILING/VIS TRENDS. * HIGH CONFIDENCE WITH PRECIP TRENDS EARLY THIS MORNING. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THU THROUGH SUN...VFR. NO SIG WX. MON...VFR. SLGT CHANCE TSRA TRS && .MARINE... 250 PM CDT THE WEAK HIGH AND LOW ARE OVER SOUTHERN MI AND WILL CONTINUE TO DISSIPATE. A BROAD TROUGH OF LOW PRESSURE EXTENDS FROM NORTHERN ONTARIO THROUGH THE CENTRAL PLAINS AND IT WILL SLIDE OVER THE LAKE TONIGHT AND ITS COLD FRONT WILL ALSO SLIDE OVER THE LAKE LATE TONIGHT/EARLY WED MORNING. FOG HAS DISSIPATED OVER THE SOUTHERN HALF OF THE LAKE BUT IS HOLDING STRONG OVER THE NORTHERN HALF. THINKING THE FOG WILL DISSIPATE AS SHOWERS MOVE OVER THE NORTHERN HALF OF THE LAKE...BUT DENSE FOG MAY STICK AROUND OVER THE NORTH HALF OF THE LAKE UNTIL THE FRONT MOVES THROUGH EARLY WED MORNING. FOR NOW EXTENDED THE DENSE FOG ADVISORY THROUGH 9PM TONIGHT FOR AREAS NORTH OF A LINE CONNECTING SHEBOYGAN WI TO PENTWATER MI. WINDS TURN W TO NW BEHIND THE FRONT AND THEN WEAKEN/BECOME MORE VARIABLE LATE ON THURSDAY AS THE HIGH MOVES OVER THE LAKE. THE HIGH CONTINUES TO MOVE EAST OF THE LAKE ON FRIDAY WITH SE TO S WINDS EXPECTED ACROSS THE LAKE. WHILE THE HIGHS CENTER MOVES OVER NEW ENGLAND FRIDAY NIGHT/SATURDAY MORNING...S WINDS ARE EXPECTED THROUGH THE REST OF THE FORECAST PERIOD. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ868 UNTIL 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1145 PM CDT TUE JUL 9 2013 .DISCUSSION... ISSUED 900 PM CDT TUE JUL 9 2013 TOUGH CALL ON TIMING OF ANY OVERNIGHT CONVECTION AS THE SHORT TERM MODELS HAVE BEEN HAVING QUITE A BIT OF DIFFICULTY TRACKING/PREDICTING STORM INITIATION/EVOLUTION TODAY SO FAR. SURFACE ANALYSIS SHOWS A COLD FRONT PROGRESSING ACROSS IOWA THIS EVENING. HOWEVER...THE NEAREST UPPER SUPPORT TO HELP WITH ANY UPDRAFTS THAT ARE TRIGGERED BY THE FRONT ARE WELL TO THE WEST IN NEBRASKA/KANSAS AND WESTERN MISSOURI...WHERE A SEVERE STORM WATCH IS IN EFFECT. WE EXPECT THE LOW LEVEL NOCTURNAL JET TO INCREASE AFTER SUNSET...AND AID IN STORM SUPPORT AS A COMPLEX TRIES TO GET ORGANIZED TOWARD MIDNIGHT ACROSS NORTHERN MISSOURI. THE LATEST IR SATELLITE PIX ARE SHOWING THAT CONVECTION IS FINALLY DEVELOPING IN NORTHWESTERN MISSOURI. THE 23Z HRRR OUTPUT PREDICTS ONE COMPLEX OF STORMS WILL RIDE NORTHEAST FROM IOWA INTO NORTHERN IL...AND ANOTHER COMPLEX IN MISSOURI WILL CURL TO THE SOUTHEAST CLIPPING SOUTHERN IL...WITH A WEAKER STORM COMPLEX BETWEEN THE TWO DRIFTING ACROSS CENTRAL IL ALONG THE COLD FRONT. WE HAVE PLENTY OF INSTABILITY AVAILABLE FOR STORMS ACROSS C IL...WITH 2000-3000 J/KG MLCAPE. SO STORMS SHOULD DEVELOP...BUT COVERAGE WILL BE MORE SCATTERED. VERY HEAVY RAINFALL WILL BE POSSIBLE. PWATS ARE AROUND 2.0 TO 2.2 INCHES. WE LOWERED POPS THIS EVENING TO SLIGHT CHANCE...AND LOWERED THE CHANCE POPS AFTER MIDNIGHT INTO THE 30-40 PCT RANGE INSTEAD OF AROUND 50 PCT. UPDATES WERE ALSO NEEDED TO SKY GRIDS. THE REMAINING GRIDS WERE GENERALLY ON TRACK. UPDATED FORECAST INFO WILL BE AVAILABLE SHORTLY. SHIMON && .AVIATION... ISSUED 1145 PM CDT TUE JUL 9 2013 DELAYED ONSET OF STORMS CONTINUES...AND THE 02Z HRRR CONTINUES TO SHOW STORMS HOLDING OFF UNTIL AFTER 11Z-12Z FOR PIA...WITH A LINE OF STORMS FROM SPI TO CMI IN PLACE AROUND 16Z-17Z. WE PUSHED THE START OF ANY VCTS LATER IN THE TAF PERIOD TO MATCH THAT PROGRESSION. STILL...THE STORMS WILL BE OF A SCATTERED COVERAGE...SO ANY SHORT PERIOD IFR/LIFR DURING ANY THUNDERSTORMS WAS LEFT OUT. EVEN MVFR WILL BE LIMITED TO ANY STORM PATHS ACROSS THE AIRPORTS. WE WILL CONTINUE THE VFR PREVAILING...UNTIL ANY STORMS DEVELOP LATE TONIGHT OR WED MORNING. WINDS WILL START OUR SOUTHWESTERLY...THEN VEER TO THE NW AFTER FROPA. BY WED AFTERNOON...TURBULENT MIXING WILL PUSH SUSTAINED WINDS IN THE 10-15KT RANGE. WINDS WILL SUBSIDE BY SUNSET...BUT REMAIN NORTH THROUGH 06Z WED NIGHT. SHIMON && .PREV DISCUSSION... ISSUED 200 PM CDT TUE JUL 9 2013 BAND OF CONVECTION THAT FIRED EARLY THIS MORNING ACROSS IOWA HAS PUSHED EAST INTO NORTH CENTRAL IL JUST AHEAD OF A MID LEVEL SHORTWAVE. UPSTREAM FROM THAT WAVE IS A MORE SIGNIFICANT SHORTWAVE OVER NORTH DAKOTA THAT WILL BRING AN END TO THE HEAT AND HUMIDITY ALONG WITH THE THREAT FOR RAIN. AT THE SURFACE...THE 18Z ANALYSIS INDICATES A WEAK OUTFLOW BOUNDARY FROM THE MORNING CONVECTION LOCATED FROM JUST WEST OF LACON AND EAST OF PEORIA AND SPRINGFIELD. THERE WAS A MIX OF SUN AND CLOUDS EARLY THIS AFTERNOON WITH TEMPERATURES CURRENTLY RANGING FROM THE UPPER 80S TO LOWER 90S WITH HEAT INDEX VALUES AROUND 100. SHORT TERM...TONIGHT THROUGH FRIDAY SEVERE STORM THREAT TONIGHT THE MAIN FORECAST CHALLENGE. WILL FOLLOW THE HRRR AND THE NCEP HI-RES ARW MODELS AS THEY HAVE SHOW A BIT MORE CONSISTENCY WITH THE DEVELOPMENT OF CONVECTION LATER THIS AFTERNOON AND ESPECIALLY TONIGHT ALONG THE SOUTHEASTWARD MOVING COLD FRONT. WILL GRADUALLY PROGRESS THE HIGHEST POPS FROM NW TO SE OVERNIGHT AS THE COLD FRONT SETTLES INTO THE REGION. FORECAST SOUNDINGS STILL CONTINUE TO SHOW AN INCREASE IN MID LEVEL WINDS COINCIDENT WITH HIGH CAPE VALUES TONIGHT IN ADVANCE OF THE STRONGER UPPER LEVEL FORCING. AS A RESULT...A FEW OF THE STORMS WILL BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND TORRENTIAL RAINFALL WITH PRECIP WATER VALUES AROUND 2 INCHES. ASSUMING ORGANIZED CONVECTION DOES DEVELOP TO OUR NORTHWEST THIS EVENING...THE EFFECTIVE OUTFLOW BOUNDARY SHOULD BE PRESSING SE INTO THE I-70 CORRIDOR BY MORNING WITH THE ACTUAL SYNOPTIC COLD FRONT LAGGING BEHIND. POPS WILL LOWER FROM NW TO SE TOMORROW MORNING IN ANTICIPATION OF THE COLD FRONT SLIPPING SE OF I-70 BY 21Z. MAIN QUESTION IS WHETHER ANY STORMS CAN RE-FIRE AHEAD OF THE FRONT TOMORROW AFTN. IF WE SEE VERY LITTLE ACTIVITY TONIGHT...CHANCES ARE WE WILL SEE STORMS RE-FIRE AHEAD OF THE COLD FRONT ALONG THE I-70 CORRIDOR BEFORE SHIFTING OFF TO OUR SOUTHEAST BY EVENING. IF STORMS DO ORGANIZE...AND TRACK QUICKLY SE LATE TONIGHT...WE MAY NOT SEE ANY DEVELOPMENT ACRS THE SOUTHEAST TOMORROW AFTN. STILL SOME UNCERTAINTY WITH RESPECT TO FRONTAL POSITION ACRS SE IL SO WILL CONTINUE TO KEEP POPS GOING DOWN THERE THRU THE AFTN HOURS. PACIFIC HIGH PRESSURE WILL THEN BUILD EAST INTO THE MIDWEST BRINGING IN COOLER AND LESS HUMID AIR STARTING WEDNESDAY NIGHT AND CONTINUING THRU THE REST OF THE WORK WEEK. ONE MORE HOT AND HUMID DAY FOR THE SOUTHEAST WITH TEMPERATURES RISING INTO THE LOWER 90S WITH HEAT INDEX VALUES AT OR JUST ABOVE 100. AFTER THAT... WE SHOULD AFTERNOON TEMPS DROP BACK INTO THE LOW TO MID 80S AND SURFACE DEW POINTS BACK TO THE UPPER 50S TO LOWER 60S THURSDAY AND ESPECIALLY ON FRIDAY. LONG TERM...SATURDAY THROUGH TUESDAY UPPER LEVEL RIDGING STILL FORECAST TO BUILD OVER THE CENTER OF THE NATION DURING THIS PERIOD BRINGING RELATIVELY QUIET WEATHER TO OUR AREA. STRONGER MID LEVEL FLOW WILL SHIFT WELL TO OUR NORTH WITH TEMPERATURES RISING BACK INTO THE UPPER 80S TO AROUND 90 BY SUNDAY AND MONDAY. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
140 AM EDT WED JUL 10 2013 .SYNOPSIS... ISSUED AT 130 AM EDT TUE JUL 9 2013 A SEASONABLY STRONG COLD FRONT WILL MOVE THROUGH THE GREAT LAKES REGION TODAY. THIS FRONT WILL BRING A CHANCE FOR THUNDERSTORMS AND LOCALLY HEAVY RAIN TO MUCH OF THE AREA TODAY. THE DAY WILL START WARM AND MUGGY. HIGH PRESSURE WILL FOLLOW TONIGHT WITH COOLER AND RELATIVELY DRIER AIR MAKING IT FEEL MUCH MORE COMFORTABLE. && .UPDATE... ISSUED AT 651 PM EDT TUE JUL 9 2013 CONVECTION EARLIER THIS AFTERNOON HAS HELPED STABILIZE THE NORTHERN HALF OF OUR CWA...WHILE MLCAPES STILL HOVER AROUND 2000 J/KG IN OUR EXTREME SOUTH. A FEW STRONG STORMS REMAIN POSSIBLE IN THIS AREA BUT FORCING IS WEAK AND DEEP LAYER SHEAR IS ONLY AROUND 20 KTS SO CONVECTION WILL REMAIN ISOLATED AND PULSEY THROUGH THE REST OF THE EVENING. LATEST WATER VAPOR LOOP AND MSAS ANALYSIS SHOW MAIN MIDLEVEL HEIGHT FALLS AND ASSOCIATED COLD FRONT REMAIN WELL NORTHWEST OF HERE. THERE IS ALSO A WEAK AREA OF SUBSIDENCE AND SOME MIDLEVEL DRY AIR AHEAD OF THIS COLD FRONT THAT IS HELPING TO SUPPRESS CONVECTION ACROSS IOWA DESPITE DECENT INSTABILITY. A FEW STORMS HAVE FIRED ACROSS WISCONSIN BUT THE PROSPECTS FOR AN ORGANIZED MCS TO DEVELOP AND PROPAGATE INTO OUR AREA AS SUGGESTED BY SOME EARLIER HI-RES RUNS APPEAR TO BE DWINDLING. LLJ WILL BEGIN TO RAMP UP LATER TONIGHT THOUGH AND THIS ENHANCED CONVERGENCE AHEAD OF THE APPROACHING COLD FRONT WILL HELP SUPPORT SOME PRECIP LATER TONIGHT WITH ABOUT 1000 J/KG OF ELEVATED INSTABILITY. WILL TAKE SOME TIME FOR THIS ACTIVITY TO REACH OUR CWA...PROBABLY AFTER MIDNIGHT...AND THE LATEST HRRR KEEPS CONVECTION FAIRLY SCATTERED. GIVEN POOR MIDLEVEL LAPSE RATES...WEAK FORCING...AND LACK OF CONVECTION/STABLE CONDITIONS IMMEDIATELY UPSTREAM WILL BE ADDING SOME DETAIL TO THE POP GRIDS FOR THIS EVENING AND SCALING BACK TO SCT/CHANCE WORDING FOR THE ENTIRE OVERNIGHT PERIOD. WIDESPREAD SEVERE WEATHER NOT EXPECTED DUE TO ELEVATED NATURE OF STORMS...MARGINAL MUCAPE VALUES...AND WEAK SHEAR. WILL LEAVE THE FLASH FLOOD WATCH UP THOUGH AS ANY SUSTAINED UPDRAFTS/TRAINING STORMS COULD PRODUCE A LOCALIZED FLOODING THREAT WITH SUCH A MOIST AIRMASS IN PLACE...PWATS STILL HOVERING AROUND 2 INCHES. UPDATED ZFP WILL BE OUT SOON. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 THUNDERSTORMS WERE CONTINUING TO DEVELOP IN A VERY UNSTABLE AIRMASS AHEAD OF AN APPROACHING UPPER LEVEL TROF AND COLD FRONT. SPC MESO ANALYSIS SHOWS PRECIP WATER VALUES EXCEEDING 2.2 INCHES OVER NRN INDIANA. HOWEVER...MID LEVEL LAPSE RATES OF 5.5 C/KM WERE REALLY LIMITING CONVECTIVE EXTENT UPSTREAM AND MAY BE A SIGNIFICANT FACTOR TONIGHT IN THE DEVELOPMENT OF MORE CONVECTION. FOR THIS PACKAGE... FAVORED MAINLY THE HIGH RES WPC MODELS...ESPECIALLY 4KM NAM. HAVE ADDED A FLASH FLOOD WATCH OVER NW OHIO WHERE 3 HOUR FLASH FLOOD GUIDANCE WAS DOWN TO ABOUT 1.0 INCH OVER SOME COUNTIES WHERE RECENT RAINFALL OF SEVERAL INCHES HAS OCCURRED. IT LOOKS TO BE HARD FOR STORMS TO PRODUCE SEVERE WEATHER LATER TODAY OR TONIGHT GIVEN A VERY HIGH WET BULB ZERO OVER 13K AND LOW BULK SHEAR WITH STABLE MID LEVEL LAPSE RATES. CURRENT THINKING WIND GUSTS SHOULD TOP OUT AROUND 40 MPH. SOME LINGERING STORMS ARE POSSIBLE WEDNESDAY...BUT GIVEN OVERNIGHT CONVECTION... LOW LEVEL CONDITIONS SHOULD BECOME TOO STABLE TO SUPPORT SEVERE STORMS. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 449 PM EDT TUE JUL 9 2013 SHRTWV MOVG INTO THE NRN PLAINS THIS AFTN EXPECTED TO BE LOCATED OVER THE GRTLKS/OH VALLEY WED EVE. ACCOMPANYING SFC CDFNT SHOULD BE JUST SE OF SERN PORTION OF CWA. A SLIGHT CHC OF SHOWERS/TSTMS LINGERING INTO WED EVE WAS MAINTAINED OVER EXTREME SE. CAA/SUBSIDENCE BEHIND THIS SYSTEM WILL RESULT IN DIMINISHING CLOUD COVER WITH COOLER AND LESS HUMID CONDITIONS WED NIGHT AND THU. FAIR WX WILL CONT THU NGT-FRI AS SFC HIGH MOVES SLOWLY EAST ACROSS THE GRTLKS. WK WAA EXPECTED OVER THE WEEKEND AS GRTLKS HIGH MOVES EAST ACROSS NEW ENGLAND AND MERGES WITH STRONG WRN ATLANTIC ANTICYCLONE. THIS ALONG WITH UPR LEVEL RIDGE EXPANDING NEWD FROM THE SRN ROCKIES/PLAINS TOWARD THE GRTLKS SHOULD RESULT IN A WARMING TREND AND DRY CONDITIONS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 131 AM EDT WED JUL 10 2013 SUBSIDENCE AND DRIER MID LEVEL AIR BEHIND EARLIER SHORT WAVE HAS KEPT TSRA FROM DEVELOPING SO FAR. 00Z ILX SOUNDING SHOWED A DECENT CAP AND THE MID LEVEL DRY AIR. WATER VAPOR SHOWS SHORT WAVE OVER NORTHERN PLAINS DIVING SOUTHEAST AND BEGINNING TO CATCH SURFACE COLD FRONT. MESOANALYSIS SHOWING UNSTABLE ATMOSPHERE IN PLACE WITH PLENTY OF MOISTURE TO FUEL TSRA. HI RES GUIDANCE SPLIT ON DEVELOPMENT OVERNIGHT BUT MOST MODELS DO SHOW AT LEAST SOME SCATTERED CONVECTION ALONG FRONT AS IT MOVES THROUGH. THUS KEPT PREVIOUS TEMPO TSRA GROUPS AT TAF SITES BUT MOVED TIMING BACK BY 2 TO 4 HOURS TO COINCIDE WITH FROPA. MAY NEED A FEW MORE HOURS OF TSRA AT KFWA BUT PREFER TO HOLD OFF AND MONITOR DEVELOPMENT BEFORE EXPANDING CHANCES GIVEN CAP. HIGH PRESSURE MOVES IN FOR AFTERNOON AND TONIGHT WITH AN EXTENDED PERIOD OF DRY WEATHER EXPECTED INTO THE WEEKEND. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR OHZ001-002-004-005- 015-016-024-025. LM...NONE. && $$ UPDATE...AGD SYNOPSIS...SKIPPER SHORT TERM...SKIPPER LONG TERM...JT AVIATION...LASHLEY VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
400 AM CDT WED JUL 10 2013 ...UPDATE TO LONG TERM DISCUSSION... .SYNOPSIS... ISSUED AT 314 AM CDT WED JUL 10 2013 A FAIRLY INTENSE SHORTWAVE TROUGH MOVED ACROSS THE NORTHERN PLAINS INTO THE UPPER MIDWEST REGION TUESDAY EVENING. THERE WAS A 70-80 KNOT 250MB JET STREAK ASSOCIATED WITH THIS STORM SYSTEM CENTERED ACROSS EASTERN SOUTH DAKOTA PER 10.00Z RAOB AND RAP ANALYSIS. THE COLD FRONT TIED TO THIS STORM SYSTEM PUSHED INTO NORTHERN KANSAS AND BY 08Z EXTENDED FROM EAST CENTRAL COLORADO TO NORTH CENTRAL KANSAS. THE THUNDERSTORM ACTIVITY THAT MOVED ACROSS PORTIONS OF SOUTHWEST AND SOUTH CENTRAL KANSAS YESTERDAY EVENING CONTINUED TO MOVE SLOWLY SOUTHEAST INTO NORTHERN OKLAHOMA. ANOTHER SMALL CLUSTER OF STRONG THUNDERSTORMS DEVELOPED ACROSS FAR NORTHWEST KANSAS ADJACENT THE SOUTHWEST NEBRASKA BORDER...WHICH WAS ALSO MOVING SOUTHEAST TOWARD THE INTERSTATE 70 CORRIDOR. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT WED JUL 10 2013 THE FORECAST FOR TODAY AND TONIGHT WILL BE CHALLENGING WITH REGARDS TO PLACEMENT, TIMING, AND INTENSITY OF THUNDERSTORMS. THE COLD FRONT WILL STALL OUT AND DISSOLVE AS IT APPROACHES THE OKLAHOMA BORDER TODAY. WINDS NORTH OF THE FRONT WILL BECOME EAST AND EVENTUALLY SOUTHEAST...ESPECIALLY ALONG THE COLORADO BORDER. A RICH SOURCE OF LOW LEVEL MOISTURE WILL BE IN PLACE NORTH OF THE FRONT WITH SURFACE DEWPOINTS IN THE MID TO UPPER 60S ACROSS PORTIONS OF CENTRAL AND WESTERN KANSAS. DESPITE THE PASSAGE OF THE COLD FRONT AND BEING ON THE NORTH SIDE OF THE BOUNDARY...AFTERNOON TEMPERATURES WILL STILL REACH THE 95 TO 98F RANGE ACROSS MUCH OF THE SOUTHWEST KANSAS REGION WITH STILL FAIRLY HIGH LOW LEVEL THICKNESSES. LOWER TROPOSPHERIC CONVERGENCE ALONG THE OLD FRONTAL ZONE ACROSS FAR SOUTHWEST KANSAS NEAR THE OKLAHOMA BORDER WILL AID IN FORMATION OF AFTERNOON THUNDERSTORMS. THERE WILL BE A GREATER AMOUNT OF SBCAPE TODAY WITH MUCH HIGHER DEWPOINT VALUES/MOISTURE CONTENT OVER YESTERDAY. THIS WOULD ARGUE FOR MORE ORGANIZED CONVECTION. ONE OR MORE MESOSCALE CONVECTIVE SYSTEMS (MCS) MAY DEVELOP FROM SOUTHWEST KANSAS NORTH-NORTHWESTWARD TO THE CHEYENNE RIDGE AREA. THE GREATER RISK FOR SEVERE STORMS WILL BE FARTHER NORTH (MOSTLY NORTH OF THE DDC FORECAST AREA) WHERE DEEP LAYER SHEAR WILL SUPPORT MORE ORGANIZED MULTI-CELL CLUSTERS AND PERHAPS A SUPERCELL OR TWO. WILL KEEP POPS IN THE 30 TO 40 PERCENT TERRITORY GIVEN THE UNCERTAINTY OF PLACEMENT AND COVERAGE OF THUNDERSTORM CLUSTERS/EVENTUAL MCS...HOWEVER POPS MAY NEED TO BE INCREASED FOR SOME SECTIONS OF THE FORECAST AREA AS SHORT TERM HIGHER RESOLUTION MODELS LIKE THE HRRR GET A BETTER HANDLE ON THE ENVIRONMENT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 400 AM CDT WED JUL 10 2013 THE EXTENDED PERIOD IS DRY AND HOT. ON THURSDAY, LEE TROUGHING AND WARM AIR ADVECTION ALONG WITH 850 HPA TEMPS IN THE 20S DEG C WILL SUPPORT MAXIMUMS IN THE MID TO UPPER 90S DEG F. NO PRECIPITATION IS EXPECTED. ON FRIDAY, THE 850 HPA WARM PLUME WILL SPREAD FARTHER NORTH AND EAST WITH 850 HPA TEMPERATURES FLIRTING WITH 30 DEG C. THIS SUPPORTS MIX DOWN TEMPERATURES IN THE LOW 100S DEG F FRIDAY AND SATURDAY. MINIMUMS WILL BE IN THE 70S DEG F THROUGH THIS PERIOD. ON SUNDAY, A JET STREAK MOVING ACROSS THE NORTHERN PLAINS INTO THE CENTRAL CANADIAN PRAIRIE PROVINCES WILL USHER IN THE PASSAGE OF A COLD FRONT ACROSS NEBRASKA AND WILL STALL OUT ACROSS THE CORNHUSKER STATE. THIS COULD KNOCK DOWN TEMPERATURES LOCALLY A FEW DEGREES. BOTH THE GFS AND ECMWF SHOW CONVECTION ASSOCIATED WITH THE FRONT AND ANY POST FRONTAL/OROGRAPHIC CONVECTION REMAINING WELL WEST/NORTHWEST OF THE AREA. AS RESULT, WENT WITH AOB 14 PERCENT PRECIPITATION PROBABILITY PERCENTAGE POINTS. THEREAFTER, THE RIDGE WILL CONTINUE TO DOMINATE WITH DRY AND HOT CONDITIONS PREVAILING. THERE COULD BE RETROGRESSION OF A SUBTROPICAL LOW NEXT WEEK, BUT THIS WILL NOT HAVE ANY SIGNIFICANT IMPACTS TO SW KANSAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1255 AM CDT WED JUL 10 2013 A SLOW-MOVING COLD FRONT WILL CONTINUE ITS PUSH THROUGH SOUTHWEST KANSAS OVERNIGHT. WINDS BEHIND THE FRONT WILL BECOME EAST TO NORTHEAST. WINDS WILL SLOWLY BECOME EAST-SOUTHEASTERLY DURING THE DAY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL LIKELY DEVELOP ALONG AND JUST NORTH OF THE FRONT LATE IN THE AFTERNOON POTENTIALLY AFFECTING DDC AND GCK TERMINALS...SO WILL INCLUDE A PROB30 FOR THUNDER DURING THE LATE AFTERNOON TO EARLY EVENING HOURS. OTHERWISE...VFR CONDITIONS WILL PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... DDC 96 70 97 73 / 30 40 10 0 GCK 94 69 98 73 / 30 40 0 0 EHA 95 69 98 72 / 30 30 0 10 LBL 97 70 99 72 / 30 30 0 0 HYS 93 69 95 73 / 20 30 20 0 P28 99 72 98 73 / 20 30 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...SUGDEN AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
315 AM CDT WED JUL 10 2013 ...UPDATED SYNOPSIS AND SHORT TERM SECTIONS... .SYNOPSIS... ISSUED AT 314 AM CDT WED JUL 10 2013 A FAIRLY INTENSE SHORTWAVE TROUGH MOVED ACROSS THE NORTHERN PLAINS INTO THE UPPER MIDWEST REGION TUESDAY EVENING. THERE WAS A 70-80 KNOT 250MB JET STREAK ASSOCIATED WITH THIS STORM SYSTEM CENTERED ACROSS EASTERN SOUTH DAKOTA PER 10.00Z RAOB AND RAP ANALYSIS. THE COLD FRONT TIED TO THIS STORM SYSTEM PUSHED INTO NORTHERN KANSAS AND BY 08Z EXTENDED FROM EAST CENTRAL COLORADO TO NORTH CENTRAL KANSAS. THE THUNDERSTORM ACTIVITY THAT MOVED ACROSS PORTIONS OF SOUTHWEST AND SOUTH CENTRAL KANSAS YESTERDAY EVENING CONTINUED TO MOVE SLOWLY SOUTHEAST INTO NORTHERN OKLAHOMA. ANOTHER SMALL CLUSTER OF STRONG THUNDERSTORMS DEVELOPED ACROSS FAR NORTHWEST KANSAS ADJACENT THE SOUTHWEST NEBRASKA BORDER...WHICH WAS ALSO MOVING SOUTHEAST TOWARD THE INTERSTATE 70 CORRIDOR. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT WED JUL 10 2013 THE FORECAST FOR TODAY AND TONIGHT WILL BE CHALLENGING WITH REGARDS TO PLACEMENT, TIMING, AND INTENSITY OF THUNDERSTORMS. THE COLD FRONT WILL STALL OUT AND DISSOLVE AS IT APPROACHES THE OKLAHOMA BORDER TODAY. WINDS NORTH OF THE FRONT WILL BECOME EAST AND EVENTUALLY SOUTHEAST...ESPECIALLY ALONG THE COLORADO BORDER. A RICH SOURCE OF LOW LEVEL MOISTURE WILL BE IN PLACE NORTH OF THE FRONT WITH SURFACE DEWPOINTS IN THE MID TO UPPER 60S ACROSS PORTIONS OF CENTRAL AND WESTERN KANSAS. DESPITE THE PASSAGE OF THE COLD FRONT AND BEING ON THE NORTH SIDE OF THE BOUNDARY...AFTERNOON TEMPERATURES WILL STILL REACH THE 95 TO 98F RANGE ACROSS MUCH OF THE SOUTHWEST KANSAS REGION WITH STILL FAIRLY HIGH LOW LEVEL THICKNESSES. LOWER TROPOSPHERIC CONVERGENCE ALONG THE OLD FRONTAL ZONE ACROSS FAR SOUTHWEST KANSAS NEAR THE OKLAHOMA BORDER WILL AID IN FORMATION OF AFTERNOON THUNDERSTORMS. THERE WILL BE A GREATER AMOUNT OF SBCAPE TODAY WITH MUCH HIGHER DEWPOINT VALUES/MOISTURE CONTENT OVER YESTERDAY. THIS WOULD ARGUE FOR MORE ORGANIZED CONVECTION. ONE OR MORE MESOSCALE CONVECTIVE SYSTEMS (MCS) MAY DEVELOP FROM SOUTHWEST KANSAS NORTH-NORTHWESTWARD TO THE CHEYENNE RIDGE AREA. THE GREATER RISK FOR SEVERE STORMS WILL BE FARTHER NORTH (MOSTLY NORTH OF THE DDC FORECAST AREA) WHERE DEEP LAYER SHEAR WILL SUPPORT MORE ORGANIZED MULTI-CELL CLUSTERS AND PERHAPS A SUPERCELL OR TWO. WILL KEEP POPS IN THE 30 TO 40 PERCENT TERRITORY GIVEN THE UNCERTAINTY OF PLACEMENT AND COVERAGE OF THUNDERSTORM CLUSTERS/EVENTUAL MCS...HOWEVER POPS MAY NEED TO BE INCREASED FOR SOME SECTIONS OF THE FORECAST AREA AS SHORT TERM HIGHER RESOLUTION MODELS LIKE THE HRRR GET A BETTER HANDLE ON THE ENVIRONMENT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 215 PM CDT TUE JUL 9 2013 A WARM AND FAIRLY DRY PERIOD BEGINS AFTER WEDNESDAY NIGHT AS A LARGE RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS INTO THE PLAINS. FOR WEDNESDAY NIGHT WILL MAINTAIN A 30 TO 40 PERCENT CHANCE OF THUNDERSTORMS JUST NORTH OF A WEAK FRONTAL BOUNDARY IN MOIST UPSLOPE REGIME ACROSS MUCH OF WESTERN KANSAS. THIS WILL BE OUR BEST CHANCE OF SEEING MEASURABLE RAINFALL INTO NEXT WEEK. WITH WEAK WINDS ALOFT NOT EXPECTING SEVERE WEATHER. THERE COULD BE SOME LOCALLY HEAVY DOWNPOURS IF STORMS GET GOING AND THEY ARE SLOW MOVING. A WESTWARD MOVING UPPER LOW BEGINS TO UNDERCUT THE RIDGE ACROSS THE SOUTHERN AND CENTRAL PLAINS FROM SUNDAY INTO TUESDAY WITH A SLIGHT CHANCE OF THUNDERSTORMS ON MONDAY NEAR A CONVERGENCE LINE, ALONG WITH SLIGHTLY COOLER TEMPERATURES. OVERNIGHT LOWS WILL BE MILD AROUND 70 TO 75 THROUGH THE PERIOD. DAYTIME HIGHS WARM BACK TO AROUND 100 TO 105 ON FRIDAY AND SATURDAY THEN COOL SLIGHTLY BACK INTO THE MID TO UPPER 90S INTO NEXT TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1255 AM CDT WED JUL 10 2013 A SLOW-MOVING COLD FRONT WILL CONTINUE ITS PUSH THROUGH SOUTHWEST KANSAS OVERNIGHT. WINDS BEHIND THE FRONT WILL BECOME EAST TO NORTHEAST. WINDS WILL SLOWLY BECOME EAST-SOUTHEASTERLY DURING THE DAY WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL LIKLEY DEVELOP ALONG AND JUST NORTH OF THE FRONT LATE IN THE AFTERNOON POTENTIALLY AFFECTING DDC AND GCK TERMINALS...SO WILL INCLUDE A PROB30 FOR THUNDER DURING THE LATE AFTERNOON TO EARLY EVENING HOURS. OTHERWISE...VFR CONDITIONS WILL PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... DDC 96 70 97 73 / 30 40 10 0 GCK 94 69 98 73 / 30 40 0 0 EHA 95 69 98 72 / 30 30 0 10 LBL 97 70 99 72 / 30 30 0 0 HYS 93 69 95 73 / 20 30 20 0 P28 99 72 98 73 / 20 30 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...KRUSE AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1138 PM MDT TUE JUL 9 2013 .UPDATE... ISSUED AT 623 PM MDT TUE JUL 9 2013 FORECAST HAS BEEN UPDATED FOR THE EXPIRATION OF THE HEAT ADVISORY AND ISSUANCE OF SEVERE THUNDERSTORM WATCH 405. STORMS SHOULD SLOWLY MOVE OUT OF THE FORECAST AREA THIS EVENING. RECENT RUNS OF THE HRRR MODEL SUGGEST THAT STORMS CURRENTLY IN NORTHWEST NEBRASKA MAY MOVE TO THE SOUTHEAST ALONG THE EDGE OF THE RIDGE OF HIGH PRESSURE. THESE STORMS WOULD MOVE INTO SOUTHWEST NEBRASKA AND PORTIONS OF NORTHWEST KANSAS LATE TONIGHT. CAN NOT RULE OUT THESE STORMS CLIPPING NORTHEAST COLORADO AS WELL. WILL CONTINUE TO WATCH THESE STORMS AS WELL AND UPDATE AS NEEDED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 143 PM MDT TUE JUL 9 2013 A HEAT ADVISORY REMAINS IN EFFECT FOR A PORTION OF THE FORECAST AREA THIS AFTERNOON AS AMBIENT TEMPERATURES AND HEAT INDEX VALUES INCREASE INTO THE 103-107 DEGREE RANGE. ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND EVENING IN THE UNSTABLE AND CONVERGENT NEAR SURFACE REGION IN THE VICINITY OF A SURFACE TROUGH THAT EXTENDS FROM WEST CENTRAL KANSAS THROUGH SOUTHEAST NEBRASKA. STORM DEVELOPMENT WILL BE AIDED BY THE LIFT ASSOCIATED WITH THE TAIL END OF THE UPPER TROUGH WILL CONTINUE TO MOVE EASTWARD OVER THE NORTHERN PLAINS THIS EVENING. SOME STORMS MAY BECOME SEVERE WITH THE STRONGER STORMS EXPECTED MAINLY ALONG THE SOUTHEAST BORDER OF THE FORECAST AREA. THE COLD FRONT POISED NORTH OF THE FORECAST AREA WILL PUSH SOUTHWARD OVERNIGHT TONIGHT AND DURING THE DAY ON WEDNESDAY. HIGH TEMPERATURES WILL BE ABOUT 10 DEGREES COOLER ON WEDNESDAY THAN ON TUESDAY...BUT ARE EXPECTED TO REACH MAINLY INTO THE LOWER TO MID 90S. THE FRONTAL BOUNDARY ENDS UP OVER THE SOUTHERN AND WESTERN SECTIONS OF THE FORECAST AREA LATE IN THE DAY ON WEDNESDAY AS SURFACE HIGH PRESSURE MOVES INTO PLACE OVER THE PLAINS STATES. SCATTERED THUNDERSTORMS...SOME BECOMING SEVERE...ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN TO THE WEST ALONG THE FRONTAL BOUNDARY ON WEDNESDAY AFTERNOON AND EVENING. STORMS WILL DECREASE IN COVERAGE AND INTENSITY AS THEY MOVE ACROSS THE REMAINDER OF THE FORECAST AREA DURING THE EVENING AND OVERNIGHT HOURS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 232 PM MDT TUE JUL 9 2013 WED NIGHT-FRIDAY...591 DM H5 RIDGE WILL BE MAIN SYNOPTIC SCALE INFLUENCE ON THE CWA THROUGH THE PERIOD AS IT BEGINS TO BUILD INTO THE AREA ON WED NIGHT BEFORE BECOMING CENTERED OVER THE CWA ON THURSDAY. SHORT WAVE TROUGH NOTED ON PROJECTED DYNAMIC TROPOPAUSE FIELDS WILL AID IN THE DEVELOPMENT OF AFTERNOON AND EVENING THUNDERSTORMS AS LARGE SCALE EASTERLY FLOW WILL KEEP AXIS OF INSTABILITY CENTERED OVER THE AREA. GIVEN EXPECTED FLOW PATTERN...STORMS SHOULD DRIFT TO THE SOUTHEAST INTO INCREASING INSTABILITY AND THINK POTENTIAL FOR PRECIPITATION EXISTS ACROSS THE ENTIRE CWA. FAIRLY CONFIDENT THAT STORMS WILL DEVELOP...BUT WITH MODELS VARYING GREATLY BETWEEN EARLY AFTERNOON INITIATION/ENDING AND PRECIPITATION MAINLY OCCURRING IN THE EVENING CONFIDENCE IN TIMING TOO LOW TO GO ABOVE THE CHANCE RANGE. GIVEN EXPECTED THERMAL AND WIND FIELDS...STRONG WAA MAY ALLOW STORMS TO LINGER THROUGH THE NIGHT ESPECIALLY IN THE EASTERN CWA. PRECIPITATION CHANCES WILL DIMINISH THROUGH THE REST OF THE PERIOD AS LARGE SCALE RIDGE MOVES OVER THE AREA BRINGING WIDESPREAD SUBSIDENCE AND INCREASED CINH. A STORM OR TWO IS POSSIBLE...BUT THINK COVERAGE WILL BE VERY LIMITED. FOR TEMPS...POTENTIAL FOR OUTFLOW FROM WED NIGHT CONVECTION LOWERS CONFIDENCE IN TEMP FORECAST ALTHOUGH GIVEN MODEL BIASES THE PAST 2 WEEKS NOT SURE IF I WANT TO GO AS COOL AS OPERATIONAL DATA SUGGESTS. ANY POSSIBLE COOL DOWN WILL BE SHORT LIVED AS TEMPERATURES REBOUND INTO THE LOW 100S BY FRIDAY. IN THE EXTENDED (FRI NIGHT-TUESDAY)...STRONG H5 RIDGE WILL CONTINUE TO DOMINATE THE WEATHER PATTERN THROUGH THE PERIOD...ALTHOUGH THERE DOES APPEAR TO BE POTENTIAL FOR SFC FRONT STALLING NEAR THE AREA BRINGING THE CHANCE FOR THUNDERSTORMS. LATEST OPERATIONAL MODELS HAVE BACKED OFF PRECIP THREAT TO SOME DEGREE...FOCUSING WEST AND NORTH OF THE CWA. WAS INCLINED TO BACK OFF POPS 10-15 PERCENT...BUT WITH GEFS STILL INDICATING A FAIRLY ROBUST PRECIP SIGNAL HAVE OPTED TO LET CURRENT CONSENSUS POPS REMAIN AS IS FOR THE TIME BEING. OTHERWISE...WARM TEMPERATURES IN THE 90S TO LOW 100S WILL CONTINUE THROUGH THE PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1138 PM MDT TUE JUL 9 2013 THUNDERSTORMS CURRENTLY LOCATED ACROSS NORTHEAST COLORADO AND SOUTHWEST NEBRASKA ARE HEADING TO THE SOUTHEAST...AND WILL LIKELY MOVE BETWEEN KGLD AND KMCK. HOWEVER...SHOWERS AND POSSIBLY THUNDERSTORMS COULD DEVELOP ALONG AN OUTFLOW BOUNDARY MOVING TOWARDS KGLD OVER THE NEXT COUPLE OF HOURS. HAVE OPTED NOT TO MENTION VCTS AT KGLD AS ACTIVITY SEEMS TO BE DIMINISHING BUT WILL INCLUDE VCSH. WINDS WILL BE PROBLEMATIC WITH LINGERING OUTFLOW BOUNDARIES AND COLD FRONT. SOUTHEAST WINDS SHOULD PICK UP LATE THIS MORNING AND COULD BECOME GUSTY. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AGAIN DURING THE LATE AFTERNOON AND MAY APPROACH KGLD DURING THE EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...RRH SHORT TERM...LOCKHART LONG TERM...JRM AVIATION...RRH
AREA FORECAST DISCUSSION
NWS JACKSON KY
131 AM EDT WED JUL 10 2013 .UPDATE... ISSUED AT 1215 AM EDT WED JUL 10 2013 WITHIN THE LAST COUPLE OF HOURS...SCT SHOWERS STARTED DEVELOPING ACROSS LMK/S CWA...AND HAVE NOW STARTED DEVELOPING ACROSS THE NORTH HALF OF OUR CWA OVER THE LAST 30 MINS/HOUR. UPDATED GRIDS TO REFLECT SCT POPS ACROSS MUCH OF THE REGION OVER THE NEXT FEW HOURS. HI-RES MODELS HAVE VERY LITTLE HANDLE ON PLACEMENT OF ONGOING OR FUTURE CONVECTIVE DEVELOPMENT...SO BASED ON RADAR TRENDS FELT IT WAS BETTER TO PUT IN SCT ACROSS MUCH OF THE REGION AS IT SEEMS MUCH OF THE CWA WILL BE IN THE VICINITY OR DIRECT PATH OF A SHOWER OVER THE NEXT FEW HOURS. WITH MOIST AND UNSTABLE ENVIRONMENT IN PLACE...DO NOT SEE ANY REASON FOR OVERALL SHOWER ACTIVITY TO DIMINISH ONCE FORMED. BUT WITH A STRONG LLVL INVERSION IN PLACE AS WELL...NOT EXPECTING ANY THUNDERSTORM DEVELOPMENT DURING THE OVERNIGHT. ALSO...LOADED IN LATEST OBSERVATIONS TO MAKE SURE OTHER SHORT TERM FORECAST PARAMETERS WERE UP TO SPEED ON CURRENT CONDITIONS. UPDATE ISSUED AT 1056 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. SPOTTER REPORTS CAME IN FROM MCCREARY COUNTY WITH TREES DOWN AND REPORTS OF FLOODING. THE ONE SPOTTER TOLD US THEY HAVE LIVED IN THE SAME PLACE FOR 44 YEARS...AND THEY NEVER SAW THE WATER RAISE THAT QUICKLY. WITH THE SATURATED GROUND FROM ALL THE RECENT RAINFALL AND THE DEWPOINTS IN THE 70S...LOCALIZED FLASH FLOODING WILL BE A REAL POSSIBILITY AND WILL NEED TO BE MONITORED CLOSELY. THE AREA RIVERS HAVE NOW TEMPORARILY ALL FALLEN BELOW ACTION STAGE. WILL HAVE TO WAIT AND SEE HOW MUCH RAIN WILL FALL OVER THE NEXT 24-36 HOURS. IT WILL NOT TAKE MUCH TO GET THE RIVERS RISING AGAIN. SPC HAS PUT PART OF EASTERN KENTUCKY IN A SLIGHT RISK FROM SEVERE THUNDERSTORMS. FROM LOOKING AT THE NAM BUFR SOUNDINGS...THIS APPEARS TO HAVE A VERY LOW CHANCE TO SEE MORE THAN ONE OR TWO SEVERE REPORTS AS THIS NEXT SYSTEM MOVES THROUGH THE AREA WEDNESDAY NIGHT AND THURSDAY. UPDATE ISSUED AT 755 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE AREA SOUTH AND WEST OF JACKSON GOOD REALLY ACTIVE IN THE LAST FEW HOURS. THE UNSTABLE MOIST AIR WAS REALLY PRIMED...ALL THAT WAS NEEDED WAS THE CONVECTIVE INITIATION. ONE OF THE STORMS GOT REALLY STRONG AND REACHED OUR RADAR BASED SEVERE WEATHER CRITERIA. NO REPORTS HAVE BEEN REPORTED YET. THE MOISTURE LADEN IS CAPABLE OF DUMPING A LOT OF RAIN IN A SHORT TIME. RADAR ESTIMATES OF GREATER THAN TWO INCHES WAS RESPONSIBLE FOR PRODUCING SOME FLASH FLOODING IN THE HOLLY HILL AREA. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 329 PM EDT TUE JUL 9 2013 ISOLD TO SCT SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE AREA THIS AFTERNOON. MORE SUBSTANTIAL AREA OF CONVECTION HAS FIRED OVER OHIO. HRRR HAS ACTUALLY BEEN DOING DECENT WITH CONVECTIVE INITIATION ACROSS AREAS NORTH OF THE OHIO RIVER. IN GENERAL IT KEEPS THE BULK OF ACTIVITY NORTH AND EAST OF OUR CWA...THOUGH RADAR TRENDS WOULD SUGGEST THAT OUR NORTHERN AND EASTERN COUNTIES MAY GET BRUSHED. INCREASED POPS ACROSS THE NORTHERN/EASTERN PORTIONS OF OUR CWA FOR THE LATE AFTERNOON AND EARLY EVENING TIME FRAME. PER THE HRRR...WITH COMPLEX OF STORMS PASSING GENERALLY TO OUR EAST THIS EVENING AND LOSS OF DIURNAL HEATING GRADUALLY DROPPED POPS OFF THROUGH THE NIGHT. HOWEVER...RAMPED POPS BACK UP TOWARDS DAWN AS SHORT TERM HIGH RESOLUTION MODELS SUGGEST THE POSSIBILITY OF THE REMNANTS OF ANOTHER COMPLEX OF STORMS ENTERING THE AREA FROM THE NORTHWEST. OTHERWISE...MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE SHORT TERM. A DEEPENING UPPER LEVEL TROUGH AND REFLECTED SFC COLD FRONT WILL GRADUALLY PUSH THROUGH THE REGION WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. PWATS OVER THE NEXT 36 TO 48 HOURS ARE SIGNIFICANT HITTING CLIMATOLOGICAL HIGHS AT TIMES. FORECAST SOUNDINGS ARE NOT IN AS GOOD AGREEMENT WITH RESPECT TO STORM MOTION THOUGH. THE GFS IS MORE PROGRESSIVE WITH MOVEMENT WHEN COMPARED TO THE HIGHER RESOLUTION RAP AND NAM. REGARDLESS...WITH SUCH HIGH PWATS AND CONSIDERING A FAIRLY SATURATED GROUND FEEL THERE WILL BE THE POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL AND MINOR HYDRO ISSUES...ESPECIALLY WITH THE STRONGER STORMS. CONFIDENCE WAS LACKING WITH RESPECT TO A WIDESPREAD THREAT SO OPTED NOT TO ISSUE ANY TYPE OF FFA. BUT MAY RECONSIDER A FLASH FLOOD WATCH WITH FUTURE FORECAST PACKAGES SHOULD MODELS COME INTO A LITTLE BETTER AGREEMENT WITH RESPECT TO DETAILS...AND SHOW A MORE SIGNIFICANT THREAT. FOR NOW WILL CONTINUE TO COVER THIS POTENTIAL IN THE HWO AND PASS CONCERNS ON TO FUTURE SHIFTS. GENERALLY FOLLOWED INHERITED TEMPS...NUDGING SLIGHTLY TOWARDS A BLEND OF MODEL GUIDANCE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 329 PM EDT TUE JUL 9 2013 THE MODELS HAVE A SIMILAR IDEA...THROUGH THE EXTENDED...OF A MID LEVEL PATTERN DOMINATED BY A LARGE AREA OF RIDGING...INITIALLY OVER THE SOUTHERN ROCKIES EXPANDING NORTHEAST WITH TIME...AND DOWNSTREAM TROUGHING THROUGH THE GREAT LAKES LATER AFFECTING MUCH OF THE EAST AND DEEP SOUTH. THE GREAT LAKES TROUGH STRENGTHENS A BIT ON THURSDAY AS ITS CORE MOVES EAST AND INTO UPSTATE NEW YORK BY 12Z FRIDAY. AT THE SAME TIME...ITS TRAILING AXIS AND MAIN ENERGY BAND WILL SWEEP SOUTHEAST THROUGH THE LOWER OHIO VALLEY AND ACROSS EAST KENTUCKY. THIS WILL ALLOW HEIGHTS TO BUILD IN FROM THE NORTHWEST THROUGH THE WEEKEND WHILE THE SOUTHERN PORTION OF THE TROUGH CUTS OFF OVER THE DEEP SOUTH AND STARTS TO CONSOLIDATE. THOUGH THE MODELS GENERALLY AGREE ON THE RIDGE PLACEMENT...THEY DIFFER ON THE DETAILS REGARDING THE LOWER HEIGHT CENTERS TO THE SOUTH AND EAST. INTO THIS MIX WILL ENTER THE UPPER HEIGHT FIELD OF CHANTAL...OR WHATEVER BECOMES OF HER...THAT COULD MOVE TO THE SOUTHEAST COAST PER THE GEM OR STAY LOCKED OUT TO THE SOUTH AS SEEN IN THE GFS AND ECMWF. EITHER WAY...ITS MOISTURE MAY START TO IMPACT THE AREA AS EARLY AS LATE SUNDAY...LINGERING THROUGH THE REST OF THE EXTENDED. FOR EAST KENTUCKY...THE RIDGE TO THE NORTH WILL BE A KEY COMPONENT IN DETERMINING OUR WEATHER INTO THE START OF NEXT WEEK. WITH THE MODELS IN BETTER AGREEMENT ON THIS FEATURE CONFIDENCE IS HIGHER IN GOING DRY THROUGH AT LEAST MIDDAY SUNDAY. THEREAFTER...THE GFS...AND TO A LESSER EXTENT THE ECMWF...DOES BRING AN UPPER LOW WEST TOWARD THE AREA FOR TUESDAY. WITH THE DECENT AGREEMENT AMONG THE MODELS ON THE RIDGE THROUGH THE WEEKEND...EXPECT THAT A BLEND WILL BE AN EFFECTIVE STARTING POINT THROUGH SUNDAY. AFTER THAT...WILL LEAN MORE TOWARD THE WEAKER...LESS AMPLIFIED...00Z ECMWF. SENSIBLE WEATHER WILL LIKELY FEATURE SOME ONGOING CONVECTION MOVING SOUTHEAST THROUGH THIS PART OF THE STATE ON THURSDAY MORNING AS A COLD FRONT PASSES THROUGH EARLY IN THE DAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING A RARE SUMMER TIME SHOT OF COOLER AND DRIER AIR FROM THE NORTH. THIS SFC HIGH...AND THE DRY WEATHER...WILL BE SUSTAINED BY THE RIDGING BUILDING ALOFT AND SHOULD SERVE TO KEEP ANY TROPICAL DERIVED MOISTURE OFF TO THE SOUTH AND EAST FOR THE BULK OF THE WEEKEND. HOWEVER...THE RIDGE ALOFT WILL WEAKEN AND MOVE BACK WEST BY LATE SUNDAY WHILE THE CORRESPONDING SFC HIGH WILL ALSO BREAK DOWN AND ALLOW HIGH DEWPOINTS INTO THE REGION FROM THE SOUTHEAST. A DIURNAL REGIME SHOULD THEN GUIDE THE CONVECTIVE DEVELOPMENTS ON MONDAY AND TUESDAY WITH BUILDING INSTABILITY AND LITTLE IN THE WAY OF CAPPING LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON...PARTICULARLY ACROSS OUR SOUTHEAST COUNTIES. THE CR GRID LOAD CAME IN REASONABLE...THOUGH DID ADJUST POPS A BIT ON SUNDAY AND MONDAY NIGHTS TO BETTER EMPHASIZE THE DIURNAL NATURE OF THE CONVECTION. ALSO...TWEAKED OVERNIGHT LOWS ON THURSDAY THROUGH SATURDAY NIGHTS TO ACCOUNT FOR TERRAIN BASED DIFFERENCES IN RADIATIONAL COOLING WHILE WE ARE BENEFITING FROM THE DRIER AIR MASS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 130 AM EDT WED JUL 10 2013 SCT SHOWERS HAVE DEVELOPED ACROSS MUCH OF THE OHIO VALLEY OVERNIGHT AND CONTINUE TO MOVE SE ACROSS THE CWA. THOUGH SHOWERS ARE QUITE LIGHT AND SHOULD NOT HAVE MUCH IN THE WAY OF IMPACTS ON THE TAF SITES...DECIDED TO GO AHEAD AND INCLUDE IN TAFS SINCE SOME RAIN WILL BE DETECTED AT ALL SITES OVER THE NEXT FEW HOURS. AS WE GO INTO THE DAYTIME HOURS...SCT TSRA WILL BEGIN TO DEVELOP ACROSS MUCH OF THE REGION IN RESPONSE TO AN APPROACHING FRONTAL SYSTEM. WENT WITH PREVIOUS FORECASTS MENTION OF VCTS INSTEAD OF PREDOMINATE TSRA SINCE IT IS STILL UNCERTAIN IF SCT CONVECTION WILL DIRECTLY IMPACT TAF SITES...AND IF SO WHEN AND HOW MUCH IMPACT WILL IT HAVE. AS THE FRONT CONTINUES TO NEAR OVERNIGHT...SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD WITH BETTER CONFIDENCE OF IMPACTS BEING FELT AT ALL TAF SITES. FORECAST SOUNDINGS CONTINUE TO SUPPORT THE POTENTIAL FOR HEAVY DOWNPOURS WITH ANY OF THESE SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT...SO COULD SEE VIS LOWER SUBSTANTIALLY FOR A PERIOD OF TIME IF SHRA/TSRA PASSES OVERHEAD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...RAY LONG TERM...GREIF AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
1215 AM EDT WED JUL 10 2013 .UPDATE... ISSUED AT 1215 AM EDT WED JUL 10 2013 WITHIN THE LAST COUPLE OF HOURS...SCT SHOWERS STARTED DEVELOPING ACROSS LMK/S CWA...AND HAVE NOW STARTED DEVELOPING ACROSS THE NORTH HALF OF OUR CWA OVER THE LAST 30 MINS/HOUR. UPDATED GRIDS TO REFLECT SCT POPS ACROSS MUCH OF THE REGION OVER THE NEXT FEW HOURS. HI-RES MODELS HAVE VERY LITTLE HANDLE ON PLACEMENT OF ONGOING OR FUTURE CONVECTIVE DEVELOPMENT...SO BASED ON RADAR TRENDS FELT IT WAS BETTER TO PUT IN SCT ACROSS MUCH OF THE REGION AS IT SEEMS MUCH OF THE CWA WILL BE IN THE VICINITY OR DIRECT PATH OF A SHOWER OVER THE NEXT FEW HOURS. WITH MOIST AND UNSTABLE ENVIRONMENT IN PLACE...DO NOT SEE ANY REASON FOR OVERALL SHOWER ACTIVITY TO DIMINISH ONCE FORMED. BUT WITH A STRONG LLVL INVERSION IN PLACE AS WELL...NOT EXPECTING ANY THUNDERSTORM DEVELOPMENT DURING THE OVERNIGHT. ALSO...LOADED IN LATEST OBSERVATIONS TO MAKE SURE OTHER SHORT TERM FORECAST PARAMTERS WERE UP TO SPEED ON CURRENT CONDITIONS. UPDATE ISSUED AT 1056 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. SPOTTER REPORTS CAME IN FROM MCCREARY COUNTY WITH TREES DOWN AND REPORTS OF FLOODING. THE ONE SPOTTER TOLD US THEY HAVE LIVED IN THE SAME PLACE FOR 44 YEARS...AND THEY NEVER SAW THE WATER RAISE THAT QUICKLY. WITH THE SATURATED GROUND FROM ALL THE RECENT RAINFALL AND THE DEWPOINTS IN THE 70S...LOCALIZED FLASH FLOODING WILL BE A REAL POSSIBILITY AND WILL NEED TO BE MONITORED CLOSELY. THE AREA RIVERS HAVE NOW TEMPORARILY ALL FALLEN BELOW ACTION STAGE. WILL HAVE TO WAIT AND SEE HOW MUCH RAIN WILL FALL OVER THE NEXT 24-36 HOURS. IT WILL NOT TAKE MUCH TO GET THE RIVERS RISING AGAIN. SPC HAS PUT PART OF EASTERN KENTUCKY IN A SLIGHT RISK FROM SEVERE THUNDERSTORMS. FROM LOOKING AT THE NAM BUFR SOUNDINGS...THIS APPEARS TO HAVE A VERY LOW CHANCE TO SEE MORE THAN ONE OR TWO SEVERE REPORTS AS THIS NEXT SYSTEM MOVES THROUGH THE AREA WEDNESDAY NIGHT AND THURSDAY. UPDATE ISSUED AT 755 PM EDT TUE JUL 9 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE AREA SOUTH AND WEST OF JACKSON GOOD REALLY ACTIVE IN THE LAST FEW HOURS. THE UNSTABLE MOIST AIR WAS REALLY PRIMED...ALL THAT WAS NEEDED WAS THE CONVECTIVE INITIATION. ONE OF THE STORMS GOT REALLY STRONG AND REACHED OUR RADAR BASED SEVERE WEATHER CRITERIA. NO REPORTS HAVE BEEN REPORTED YET. THE MOISTURE LADEN IS CAPABLE OF DUMPING A LOT OF RAIN IN A SHORT TIME. RADAR ESTIMATES OF GREATER THAN TWO INCHES WAS RESPONSIBLE FOR PRODUCING SOME FLASH FLOODING IN THE HOLLY HILL AREA. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 329 PM EDT TUE JUL 9 2013 ISOLD TO SCT SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE AREA THIS AFTERNOON. MORE SUBSTANTIAL AREA OF CONVECTION HAS FIRED OVER OHIO. HRRR HAS ACTUALLY BEEN DOING DECENT WITH CONVECTIVE INITIATION ACROSS AREAS NORTH OF THE OHIO RIVER. IN GENERAL IT KEEPS THE BULK OF ACTIVITY NORTH AND EAST OF OUR CWA...THOUGH RADAR TRENDS WOULD SUGGEST THAT OUR NORTHERN AND EASTERN COUNTIES MAY GET BRUSHED. INCREASED POPS ACROSS THE NORTHERN/EASTERN PORTIONS OF OUR CWA FOR THE LATE AFTERNOON AND EARLY EVENING TIME FRAME. PER THE HRRR...WITH COMPLEX OF STORMS PASSING GENERALLY TO OUR EAST THIS EVENING AND LOSS OF DIURNAL HEATING GRADUALLY DROPPED POPS OFF THROUGH THE NIGHT. HOWEVER...RAMPED POPS BACK UP TOWARDS DAWN AS SHORT TERM HIGH RESOLUTION MODELS SUGGEST THE POSSIBILITY OF THE REMNANTS OF ANOTHER COMPLEX OF STORMS ENTERING THE AREA FROM THE NORTHWEST. OTHERWISE...MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE SHORT TERM. A DEEPENING UPPER LEVEL TROUGH AND REFLECTED SFC COLD FRONT WILL GRADUALLY PUSH THROUGH THE REGION WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. PWATS OVER THE NEXT 36 TO 48 HOURS ARE SIGNIFICANT HITTING CLIMATOLOGICAL HIGHS AT TIMES. FORECAST SOUNDINGS ARE NOT IN AS GOOD AGREEMENT WITH RESPECT TO STORM MOTION THOUGH. THE GFS IS MORE PROGRESSIVE WITH MOVEMENT WHEN COMPARED TO THE HIGHER RESOLUTION RAP AND NAM. REGARDLESS...WITH SUCH HIGH PWATS AND CONSIDERING A FAIRLY SATURATED GROUND FEEL THERE WILL BE THE POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL AND MINOR HYDRO ISSUES...ESPECIALLY WITH THE STRONGER STORMS. CONFIDENCE WAS LACKING WITH RESPECT TO A WIDESPREAD THREAT SO OPTED NOT TO ISSUE ANY TYPE OF FFA. BUT MAY RECONSIDER A FLASH FLOOD WATCH WITH FUTURE FORECAST PACKAGES SHOULD MODELS COME INTO A LITTLE BETTER AGREEMENT WITH RESPECT TO DETAILS...AND SHOW A MORE SIGNIFICANT THREAT. FOR NOW WILL CONTINUE TO COVER THIS POTENTIAL IN THE HWO AND PASS CONCERNS ON TO FUTURE SHIFTS. GENERALLY FOLLOWED INHERITED TEMPS...NUDGING SLIGHTLY TOWARDS A BLEND OF MODEL GUIDANCE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 329 PM EDT TUE JUL 9 2013 THE MODELS HAVE A SIMILAR IDEA...THROUGH THE EXTENDED...OF A MID LEVEL PATTERN DOMINATED BY A LARGE AREA OF RIDGING...INITIALLY OVER THE SOUTHERN ROCKIES EXPANDING NORTHEAST WITH TIME...AND DOWNSTREAM TROUGHING THROUGH THE GREAT LAKES LATER AFFECTING MUCH OF THE EAST AND DEEP SOUTH. THE GREAT LAKES TROUGH STRENGTHENS A BIT ON THURSDAY AS ITS CORE MOVES EAST AND INTO UPSTATE NEW YORK BY 12Z FRIDAY. AT THE SAME TIME...ITS TRAILING AXIS AND MAIN ENERGY BAND WILL SWEEP SOUTHEAST THROUGH THE LOWER OHIO VALLEY AND ACROSS EAST KENTUCKY. THIS WILL ALLOW HEIGHTS TO BUILD IN FROM THE NORTHWEST THROUGH THE WEEKEND WHILE THE SOUTHERN PORTION OF THE TROUGH CUTS OFF OVER THE DEEP SOUTH AND STARTS TO CONSOLIDATE. THOUGH THE MODELS GENERALLY AGREE ON THE RIDGE PLACEMENT...THEY DIFFER ON THE DETAILS REGARDING THE LOWER HEIGHT CENTERS TO THE SOUTH AND EAST. INTO THIS MIX WILL ENTER THE UPPER HEIGHT FIELD OF CHANTAL...OR WHATEVER BECOMES OF HER...THAT COULD MOVE TO THE SOUTHEAST COAST PER THE GEM OR STAY LOCKED OUT TO THE SOUTH AS SEEN IN THE GFS AND ECMWF. EITHER WAY...ITS MOISTURE MAY START TO IMPACT THE AREA AS EARLY AS LATE SUNDAY...LINGERING THROUGH THE REST OF THE EXTENDED. FOR EAST KENTUCKY...THE RIDGE TO THE NORTH WILL BE A KEY COMPONENT IN DETERMINING OUR WEATHER INTO THE START OF NEXT WEEK. WITH THE MODELS IN BETTER AGREEMENT ON THIS FEATURE CONFIDENCE IS HIGHER IN GOING DRY THROUGH AT LEAST MIDDAY SUNDAY. THEREAFTER...THE GFS...AND TO A LESSER EXTENT THE ECMWF...DOES BRING AN UPPER LOW WEST TOWARD THE AREA FOR TUESDAY. WITH THE DECENT AGREEMENT AMONG THE MODELS ON THE RIDGE THROUGH THE WEEKEND...EXPECT THAT A BLEND WILL BE AN EFFECTIVE STARTING POINT THROUGH SUNDAY. AFTER THAT...WILL LEAN MORE TOWARD THE WEAKER...LESS AMPLIFIED...00Z ECMWF. SENSIBLE WEATHER WILL LIKELY FEATURE SOME ONGOING CONVECTION MOVING SOUTHEAST THROUGH THIS PART OF THE STATE ON THURSDAY MORNING AS A COLD FRONT PASSES THROUGH EARLY IN THE DAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING A RARE SUMMER TIME SHOT OF COOLER AND DRIER AIR FROM THE NORTH. THIS SFC HIGH...AND THE DRY WEATHER...WILL BE SUSTAINED BY THE RIDGING BUILDING ALOFT AND SHOULD SERVE TO KEEP ANY TROPICAL DERIVED MOISTURE OFF TO THE SOUTH AND EAST FOR THE BULK OF THE WEEKEND. HOWEVER...THE RIDGE ALOFT WILL WEAKEN AND MOVE BACK WEST BY LATE SUNDAY WHILE THE CORRESPONDING SFC HIGH WILL ALSO BREAK DOWN AND ALLOW HIGH DEWPOINTS INTO THE REGION FROM THE SOUTHEAST. A DIURNAL REGIME SHOULD THEN GUIDE THE CONVECTIVE DEVELOPMENTS ON MONDAY AND TUESDAY WITH BUILDING INSTABILITY AND LITTLE IN THE WAY OF CAPPING LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON...PARTICULARLY ACROSS OUR SOUTHEAST COUNTIES. THE CR GRID LOAD CAME IN REASONABLE...THOUGH DID ADJUST POPS A BIT ON SUNDAY AND MONDAY NIGHTS TO BETTER EMPHASIZE THE DIURNAL NATURE OF THE CONVECTION. ALSO...TWEAKED OVERNIGHT LOWS ON THURSDAY THROUGH SATURDAY NIGHTS TO ACCOUNT FOR TERRAIN BASED DIFFERENCES IN RADIATIONAL COOLING WHILE WE ARE BENEFITING FROM THE DRIER AIR MASS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 755 PM EDT TUE JUL 9 2013 LOTS OF THUNDERSTORMS NEAR THE TAF STATIONS THIS EVENING. THE RADAR IS INDICATING OUTFLOW BOUNDARIES BEING PRODUCED BY THE THUNDERSTORMS MOVING MANY MILES OUT AHEAD OF THE STORMS. THIS WOULD MEAN THAT AN UNEXPECTED LOW LEVEL WIND SHEAR WELL AHEAD OF THE APPROACHING STORM. LOZ SHOULD BE SEEING A THUNDERSTORM AT THE STATION BETWEEN 00-01Z. FOR FOG AND MIST...WENT WITH PERSISTENCE FOR THE FORECAST. THIS MAY HAVE TO BE RETHOUGHT IF LOZ GET LOTS OF RAIN THIS NEXT HOUR. TOMORROW SHOULD HAVE MORE CONVECTIVE ACTIVITY THAN TODAY WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...RAY LONG TERM...GREIF AVIATION...JJ
AREA FORECAST DISCUSSION
NWS DULUTH MN
310 AM CDT WED JUL 10 2013 .SHORT TERM.../NOW - TONIGHT/ AT 300AM/0800Z...THERE WAS A MID/UPPER LEVEL TROUGH CENTERED FROM WESTERN ONTARIO TO THE EASTERN FORECAST AREA. SURFACE HIGH PRESSURE WAS CENTERED IN THE WESTERN DAKOTAS. MUCH OF THE NORTHLAND HAD CLEAR SKIES...EXCEPT FOR PARTS OF THE EASTERN AND NORTHERN FORECAST AREA. MORE EXTENSIVE CLOUD COVER WAS LOCATED FARTHER NORTH AND EAST OF THE NORTHLAND...WHILE MUCH OF THE NORTHERN PLAINS HAD CLEAR SKIES. MUCH OF THE NORTHLAND HAD 5 TO 10 MPH WNW TO NW WINDS...WHICH WAS HELPING TO KEEP THE TEMPERATURES UP. THE TEMPERATURES RANGED FROM THE MID 50S TO MID 60S. TODAY...THE SURFACE HIGH PRESSURE IN THE NORTHERN PLAINS WILL BEGIN TO SHIFT EAST INTO THE UPPER MIDWEST. THE NORTHLAND CAN EXPECT RELATIVELY SUNNY AND WEATHER EARLY THIS MORNING. HOWEVER...SCATTERED CUMULUS WILL LIKELY DEVELOP BY THE AFTERNOON SINCE THE MODEL SOUNDINGS INDICATE RELATIVELY LOW CONVECTIVE TEMPERATURES IN THE BREEZY NW FLOW. THE LATEST HRRR RUNS ARE PICKING UP ON THE SCATTERED CUMULUS. ALSO...THE NAM12 AND GFS ARE SHOWING A SHORTWAVE MOVING INTO THE WESTERN FORECAST AREA THIS AFTERNOON...AND THE NAM12/DLHWRF/WRF MODELS ARE HINTING AT A LOW THREAT OF SHOWERS AND STORMS WITH THIS SHORTWAVE. I ADDED ISOLATED STORMS ACROSS THE WESTERN FORECAST AREA FOR THIS AFTERNOON AND EARLY EVENING. HIGH TEMPERATURES SHOULD BE IN THE MID 70S TO NEAR 80 DEGREES. TONIGHT...THE RELATIVELY DRY CONDITIONS THAT WILL DEVELOP THIS AFTERNOON DUE TO THE MIXING IN THE NW FLOW...COMBINED WITH THE WEAKENING WINDS TONIGHT AS HIGH PRESSURE MOVES INTO THE UPPER MIDWEST...WILL HELP FOR DECENT RADIATIONAL COOLING TONIGHT. I LOWERED THE LOW TEMPERATURE FORECAST BY A COUPLE TO FEW DEGREES. THE LOW TEMPERATURES SHOULD AROUND 50 DEGREES TO THE MID 50S...BUT I COULD SEE ISOLATED AREAS GETTING DOWN TO THE MID 40S DEPENDING ON AFTERNOON DEW POINT TEMPERATURES. DESPITE THE CLEAR SKIES AND NEGLIGIBLE WINDS THAT WILL DEVELOP...I THINK THE THREAT OF FOG IS LOW BECAUSE OF THE RELATIVELY DRY CONDITIONS THAT WILL DEVELOP IN THE AFTERNOON. IF THERE IS ANY FOG...IT WILL PROBABLY DEVELOP VERY LATE IN THE NIGHT AND BE ISOLATED. .LONG TERM.../THURSDAY - TUESDAY/ FOCUS IN EXTENDED ON RETURN OF UPPER LEVEL RIDGE AND SRLY FLOW WITH INCREASING H85 TEMPS THURSDAY NIGHT/FRIDAY...THEN STALLED BAROCLINIC ZONE THAT WILL BECOME FOCUS FOR RAIN/TSTORMS THROUGH THE WEEKEND. LONG RANGE MODELS CONTINUE TO STRUGGLE WITH THE PLACEMENT OF THE STALLED FRONT AND ASSOCIATED BAND OF PRECIPITATION. HAVE POPS MOVING INTO NW ZONES FRIDAY NIGHT...WITH WIDESPREAD HIGH CHANCE/LIKELY POPS FOR SHOWERS AND TSTORMS ACROSS THE CWA SATURDAY/SUNDAY. LATEST NAM DEPICTS VERY HIGH PWATS APPROACHING 2 INCHES SPREADS OVER THE NORTHLAND THROUGH FRIDAY EVENING. IF THE BOUNDARY DOES STALL OVER A PORTION OF THE FORECAST AREA...THE ABUNDANT MOISTURE AND PROLONGED PERIOD OF RAIN COULD LEAD TO LOCALIZED FLOODING CONCERNS. THE MAIN THREAT FOR HEAVY RAIN AT THIS TIME LOOKS TO BE FRIDAY NIGHT THROUGH SATURDAY NIGHT. && .AVIATION.../06Z TAF ISSUANCE/ VFR CONDITIONS HAVE RETURNED TO THE TERMINALS THIS EVENING AFTER A COLD FRONT MOVED THROUGH THE AREA. DRIER AIR FILTERING INTO THE AREA FROM THE NORTHWEST IS EXPECTED TO KEEP FOG FROM FORMING AT MOST TERMINALS...BUT KHYR MAY STILL FORM SOME...DUE TO THE LATER TIMING OF THE DRIER AIR. IN THE 14Z- 16Z TIME RANGE WEDNESDAY NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 10-15KTS AND GUST TO 20KTS MOST LOCATIONS...BUT LIGHTER AT KHYR. WINDS TO DIMINISH AGAIN AFTER 23Z. VFR CONDITIONS EXPECTED 14Z THROUGH END OF TAF PERIOD. && .POINT TEMPS/POPS... DLH 76 54 79 58 / 10 10 0 0 INL 77 51 82 62 / 20 10 0 10 BRD 79 55 82 64 / 20 20 0 0 HYR 80 50 81 56 / 10 0 0 0 ASX 76 51 79 56 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LSZ140-141. && $$ SHORT TERM...GROCHOCINSKI LONG TERM....GRANING AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS DULUTH MN
1255 AM CDT WED JUL 10 2013 .AVIATION...06Z TAFS... VFR CONDITIONS HAVE RETURNED TO THE TERMINALS THIS EVENING AFTER A COLD FRONT MOVED THROUGH THE AREA. DRIER AIR FILTERING INTO THE AREA FROM THE NORTHWEST IS EXPECTED TO KEEP FOG FROM FORMING AT MOST TERMINALS...BUT KHYR MAY STILL FORM SOME...DUE TO THE LATER TIMING OF THE DRIER AIR. IN THE 14Z- 16Z TIME RANGE WEDNESDAY NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 10-15KTS AND GUST TO 20KTS MOST LOCATIONS...BUT LIGHTER AT KHYR. WINDS TO DIMINISH AGAIN AFTER 23Z. VFR CONDITIONS EXPECTED 14Z THROUGH END OF TAF PERIOD. && .PREV DISCUSSION... /ISSUED 649 PM CDT TUE JUL 9 2013/ UPDATE... HAVE SENT OUT SOME UPDATES TO REFINE PRECIPITATION AND CLOUD TRENDS THIS EVENING. THE TROUGH AXIS SWEEPING ACROSS THE AREA NOW THAT IS ASSOCIATED WITH SOME SHOWERS/ISOLATED TSRA ARE VERY LIKELY THE TAIL END OF PRECIPITATION FOR THE EVENING...THOUGH CANNOT RULE OUT A FEW ISOLATED SHOWERS AS CAN BE SEEN BACK AROUND WASKISH. THIS TROUGH AXIS IS ALSO THE LEADING EDGE OF THE DRY AIR...WHERE DEWPOINTS GO FROM THE MID 60S AROUND HIBBING...DROPPING TO THE MID 50S BY BAUDETTE. PREV DISCUSSION... /ISSUED 314 PM CDT TUE JUL 9 2013/ SHORT TERM...THROUGH EARLY WEDNESDAY EVENING. COVERAGE OF SHOWERS AND STORMS HAVE DIMINISHED OVER MUCH OF THE NORTHLAND THIS AFTERNOON...WITH HIGHEST CONCENTRATION OVER OUR FAR EASTERN ZONES ALONG AND AHEAD OF THE LOW LEVEL BOUNDARY. ADDITIONAL ISOLATED SHOWERS WERE OCCURRING BEHIND THIS BOUNDARY WITH OTHERS ASSOCIATED WITH THE UPPER WAVE OVER SOUTHERN MANITOBA/NORTHERN NORTH DAKOTA. LATEST HRRR HAS A DECENT HANDLE ON CURRENT CONVECTION...AND SHOWS COVERAGE REMAINING LIMITED TONIGHT. WE DO HAVE POPS THIS EVENING OVER MUCH OF THE NORTHLAND...BUT DECREASE THEM FROM WEST TO EAST TONIGHT. THE THREAT FOR SEVERE STORMS IS LOW AS BEST CONVERGENCE SHOULD BE EXITING OUR CWA THIS EVENING...AND STABILITY AND SHEAR ARE NOT REAL SUPPORTIVE GIVEN THE AMOUNT OF LIFT. SOME FOG MAY LINGER THIS EVENING AROUND LAKE SUPERIOR...PARTICULARLY UP THE NORTH SHORE...BUT THEN THAT SHOULD DIMINISH OVERNIGHT AS WINDS TURN NORTHWEST BEHIND THE FRONT. WEDNESDAY SHOULD FEATURE PARTLY TO MOSTLY SUNNY SKIES WITH HIGH PRESSURE BUILDING IN. TEMPERATURES WILL BE IN THE SEVENTIES. WE DO EXPECT GOOD MIXING WITH STEEP LAPSE RATES. THIS WILL LEAD TO SOME GUSTY WINDS BY AFTERNOON. SOME STEEPER LAPSE RATES OVER THE ARROWHEAD AND IT`S PROXIMITY TO THE EXITING UPPER TROUGH SHOULD BE ENOUGH TO CAUSE SOME THICKER CLOUDS UP THERE BY WEDNESDAY AFTERNOON. WE LEFT THAT AREA DRY...BUT LATER SHIFTS WILL HAVE TO MONITOR FOR THE POSSIBLE ADDITION OF A FEW SHOWERS OR THUNDERSTORMS IN THE AFTERNOON. LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. A LARGE SFC HIGH AND ASSOCIATED UPPER RIDGE WILL BE BUILDING IN ACROSS THE UPPER MIDWEST WED NIGHT...ALONG WITH DRYING CONDITIONS AND MOSTLY CLEAR SKIES. RELATIVELY COOL TEMPS COULD DEVELOP EARLY THUR MORNING UNDER CALM WINDS AND STRONG RADIATIONAL COOLING. SHOULD SEE MOSTLY SUNNY SKIES ON THURSDAY WITH HIGHS IN THE 70S AROUND THE LAKE AND 80S INLAND. THUR NIGHT SHOULD REMAIN MOSTLY CLEAR WITH HIGH PRESSURE IN PLACE. HOWEVER...AS THE SFC HIGH SHIFTS EWD...A RETURN SLY FLOW WILL DEVELOP AND BEGIN TO USHER IN MORE CLOUD COVER AND A RICHER MORE UNSTABLE AIR MASS AHEAD OF THE NEXT SFC TROUGH/COLD FRONT EXPECTED TO MOVE INTO THE REGION THIS WEEKEND. FRIDAY WILL BE A TRANSITION DAY WITH CLOUDS INCREASING FROM THE W...BUT MINIMAL PRECIP CHANCES UNTIL LATER FRI NIGHT. MODEL GUIDANCE IS INDICATING THAT THE SFC FRONT WILL STALL OUT ACROSS NRN MN/WRN LAKE SUPERIOR ALONG THE NRN/NWRN FRINGES OF AN ELONGATED RIDGE SITUATED OVER THE MID MS VALLEY/SRN GREAT LAKES REGION. THIS PATTERN WOULD ALLOW FOR A PROLONGED PERIOD OF SHOWERS AND STORMS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...WITH POTENTIALLY PERIODS OF HEAVY RAIN. WILL NEED TO MONITOR THIS PATTERN AND ANY CHANGES DURING THE NEXT COUPLE DAYS. COULD BE DEALING WITH HYDRO ISSUES SAT THROUGH MON. OTHERWISE...TEMPERATURES REMAIN VERY SEASONAL...WITH HIGHS IN THE 70S AND LOWER 80S AND LOWS IN THE 50S AND LOWER 60S. && .POINT TEMPS/POPS... DLH 77 56 79 58 / 0 0 0 0 INL 76 55 82 61 / 10 0 0 10 BRD 78 55 82 62 / 0 0 0 10 HYR 78 52 81 58 / 0 0 0 0 ASX 76 51 79 57 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...LE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT WED JUL 10 2013 .SYNOPSIS... ISSUED AT 313 AM CDT WED JUL 10 2013 THE 07Z MSL ANALYSIS SHOWED TWO MAIN BOUNDARIES ACROSS THE PLAINS. ONE WAS THE SURFACE FRONT FROM A LOW IN SOUTHEAST COLORADO ACROSS OKLAHOMA TO SOUTHWEST MISSOURI. THE OTHER WAS A TROUGH WITH ITS PRESENCE BETRAYED BY WIND FIELDS ACROSS SOUTHWEST NEBRASKA. SATELLITE DERIVED PRODUCT IMAGERY...WHERE IT WAS NOT POLLUTED WITH CLOUD...SHOWED AN AXIS OF MAXIMUM PRECIPITABLE WATER AND INSTABILITY FROM EAST CENTRAL WYOMING ACROSS THE NEBRASKA PANHANDLE AND SOUTHWEST NEBRASKA TO SOUTHEAST NEBRASKA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED JUL 10 2013 ONCE AGAIN...THE LOCATIONS OF CONVECTIVE DEVELOPMENT WILL DEPEND ON THE LOCATIONS OF THE FRONT AND OTHER BOUNDARIES FROM CONVECTION OVERNIGHT. IT IS DIFFICULT TO FIND ANY CONSENSUS AMONG THE AVAILABLE MODELS WITH THE SHORT RANGE FORECAST. THE RAP13 AND HRRR SEEM TO BE ON THE SAME PAGE WITH CONVECTION DEVELOPING FAIRLY EARLY TODAY IN WESTERN NEBRASKA. THE GEM REGIONAL AND THE GFS SEEM TO FAVOR THIS EVENING AND LATE NIGHT FOR THE TIMING. AS WAS THE CASE YESTERDAY...THE LOCATION OF BOUNDARIES AND THE FRONT IS A LITTLE UP IN THE AIR. AT FIRST...CENTRAL AND SOUTHWEST NEBRASKA APPEARS TO BE THE LOCATION TO WATCH WHERE THERE WAS CONVECTION YESTERDAY EVENING. LOOKING AT THE RAP13 CONVECTIVE PARAMETERS...THE SURFACE-BASED CONVECTIVE INHIBITION APPROACHES ZERO J/KG BY LATE MORNING TO EARLY AFTERNOON IN THE SOUTHWEST. ALSO...CONVECTIVE POTENTIAL ENERGY OF 1500-2500J/KG AND SFC-6KM BULK SHEAR INCREASING TO 40-50KT COULD SUPPORT LARGE HAIL. FOR LATER PERIODS...THE FRONT LIFTING ONTO THE HIGH PLAINS WOULD BE A GOOD FOCUS FOR CONVECTION TO DEVELOP THIS EVENING OR OVERNIGHT AS IT MOVES INTO WESTERN NEBRASKA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 313 AM CDT WED JUL 10 2013 THE EXPANSIVE RIDGE OF HIGH PRESSURE THAT HAS BEEN ANCHORED ACROSS THE FOUR CORNERS REGION FOR DAYS...WILL BUILD NORTH OVER OUR AREA THURSDAY INTO FRIDAY. THIS WILL BRING WARMING TEMPERATURES ALOFT...WHICH WILL CAP THE ATMOSPHERE...AND LITTLE IN THE WAY OF T-STORM ACTIVITY IS EXPECTED. IT WILL BE QUITE HOT AS WELL...WITH HIGHS IN THE 90S TO AROUND 100 DEGREES. HUMIDITY WILL REMAIN AS WELL...ESPECIALLY EAST OF HIGHWAY 83...AND A HEAT ADVISORY MAY BE NEEDED FRIDAY AND POSSIBLE SATURDAY. BY LATER SATURDAY INTO SUNDAY...A SHORTWAVE WILL SKIRT ACROSS CANADA. THIS WILL DRIVE A COLD FRONT SOUTH INTO THE REGION...WITH RETURNING CHANCES FOR T-STORMS WITH THE ARRIVAL OF THE FRONT. THE UPPER LEVEL HIGH WILL ALSO BE TEMPORALLY SUPPRESSED SOUTH...WITH TEMPERATURES COOLING JUST A FEW DEGREES. THE RIDGE IS FORECASTED TO BUILD OVERHEAD AGAIN BY TUESDAY INTO WEDNESDAY...WITH HOT WEATHER CONTINUE AND ONLY AN ISOLATED T-STORM AT BEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1130 PM CDT TUE JUL 9 2013 MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT AT BOTH THE KVTN AND KLBF TERMINALS...WITH SOME SCATTERED HIGH CLOUDINESS POSSIBLE. SOME SCATTERED MID LEVEL CLOUDINESS WILL DEVELOP WEDNESDAY AFTERNOON AS A DISTURBANCE APPROACHES WESTERN AND NORTH CENTRAL NEBRASKA. ISOLATED THUNDERSTORMS WILL BE POSSIBLE...PARTICULARLY OVER SOUTHWESTERN AND WESTERN NEBRASKA WEDNESDAY AFTERNOON AND EVENING. WITH LIMITED COVERAGE EXPECTED...WILL FORGO MENTION OF THUNDERSTORMS IN THE 06Z TAFS. WINDS WILL BE FROM THE EAST SOUTHEAST OR SOUTHEAST ON WEDNESDAY AT 10 TO 20 KTS...DIMINISHING WEDS EVENING TO UNDER 10 KTS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SPRINGER SHORT TERM...SPRINGER LONG TERM...TAYLOR AVIATION...BUTTLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1155 PM CDT TUE JUL 9 2013 .UPDATE... UPDATED TO KEEP SMALL POPS IN THE FAR SOUTHEAST PART OF NEBRASKA...BUT LET GO OF THE SEVERE THUNDERSTORM WATCH. && .DISCUSSION... AN OUTLFLOW BOUNDARY IS PUSHING TOWARD THE NEBRASKA/KANSAS BORDER...SO LEFT SOME ISOLATED TSRA CHANCES INTO THE FAR SOUTHEAST NEBRASKA ZONES AND COULD SEE SOME WINDS GUSTS TO 30 OR 35 MPH. OTHERWISE COOLER...RELATIVELY DRIER CONDITIONS WILL BUILD IN TONIGHT && .AVIATION... 06Z TAFS FOR KOFK...KLNK AND KOMA. VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS HIGH PRESSURE BUILDS INTO THE REGION. && .PREV DISCUSSION... /ISSUED 654 PM CDT TUE JUL 9 2013/ UPDATE... UPDATE TO INCLUDE SEVERE THUNDERSTORM WATCH FOR PARTS OF SOUTHEAST NEBRASKA THROUGH 1AM AND ALLOW THE HEAT ADVISORY TO EXPIRE. DISCUSSION... SOME STORMS HAVE DEVELOPED IN THE UPSLOPE REGION IN WESTERN AND CENTRAL NEBRASKA AND HAVE CONTINUED THIS EVENING. THERE IS A COLD FRONT WITH POOLING OF INSTABILITY AND DECENT DEEP LAYER SHEAR AHEAD OF THE FRONT...VERY WARM TEMPERATURE ARE HINDERING STORM DEVELOPMENT FARTHER THUS FAR. SHOULD STORMS DEVELOP...THEY COULD BECOME SEVERE. AVIATION... 00Z TAFS FOR KOFK...KLNK AND KOMA. VFR CONDITIONS THROUGH THE PERIOD. WILL CONTINUE TO MONITOR STORM DEVELOPMENT FROM CENTRAL NEBRASKA. FOR NOW AM COUNTING ON STORMS TO BE SOUTH OF THE LNK TAF SITE AND HAVE NOT INCLUDED IN THE TAF. A COLD FRONT IS PUSHING THROUGH AND NORTH SURFACE WINDS MAY BUMP UP TO 10 TO 15KT BEHIND IT...BUT SHOULD SETTLE DOWN AFTER 02Z-03Z. PREV DISCUSSION... /ISSUED 313 PM CDT TUE JUL 9 2013/ DISCUSSION... THUNDERSTORM CHANCES TONIGHT AND POSSIBLY WEDNESDAY NIGHT...THEN HEAT POTENTIAL INTO NEXT WEEK...ARE THE PRIMARY FORECAST CONCERNS. UPPER RIDGE WAS SPRAWLING ACROSS THE SOUTH HALF OF THE CONUS TODAY...WITH OUR AREA IN THE TRANSITION ZONE BETWEEN RIDGE TO THE SOUTH AND FASTER MID LEVEL FLOW TO THE NORTH. A POTENT SHORTWAVE WAS NOTED IN NORTH DAKOTA SWEEPING EAST THIS AFTERNOON...AND WILL SETTLE INTO THE GREAT LAKES WEDNESDAY AFTERNOON BEFORE CARVING OUT A TROUGH OVER NEW ENGLAND BY SATURDAY. SHORTWAVE WILL DRIVE A COLD FRONT SOUTH OF OUR AREA TONIGHT AND WEDNESDAY...THEN ALLOW UPPER RIDGE TO BUILD INTO THE PLAINS THIS WEEKEND INTO NEXT WEEK. EARLY AFTERNOON SURFACE ANALYSIS SHOWED A WIND SHIFT SETTLING SOUTH TOWARD A COLUMBUS TO TEKAMAH LINE...WITH A SECONDARY BOUNDARY MOVING OUT OF SOUTH DAKOTA INTO NORTHEAST NEBRASKA. AIRMASS BEHIND THIS SECOND BOUNDARY WAS CHARACTERIZED BY DEW POINTS IN THE 60S AND TEMPERATURES CLOSER TO 80. SOUTH OF BOTH BOUNDARIES...TEMPERATURES WERE CLIMBING INTO THE 90S WITH DEW POINTS IN THE LOW TO MID 70S...PUTTING HEAT INDICES INTO THE 100S AT MANY SPOTS. WILL MAINTAIN OUR CURRENT HEAT ADVISORY INTO THE EARLY EVENING...AND MAY TRIM SOME NORTHERN COUNTIES BASED ON OBS. INSTABILITY WAS ALSO INCREASING MARKEDLY ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST IOWA WHERE SURFACE-BASED CAPES WERE WELL OVER 3000 J/KG ACCORDING TO LATEST RAP ANALYSIS. HOWEVER FORECAST SOUNDINGS SHOW A SIGNIFICANT WARM NOSE ABOVE SURFACE LAYER WAS CAPPING ANY ATTEMPT AT CONVECTION SO FAR. AS FRONTAL BOUNDARY SETTLES INTO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA THIS EVENING...COMBINED WITH A LITTLE MORE HEATING AND A WEAK IMPULSE SLIDING ACROSS NORTHERN KANSAS...EXPECT SCATTERED THUNDERSTORMS TO FIRE IN OUR SOUTHERN CWA...MOST LIKELY SOUTH OF INTERSTATE 80. IF THOSE DO OCCUR...AMOUNT OF INSTABILITY AND MODEST BULK SHEAR NEAR 35KT SUGGEST SEVERE STORMS ARE POSSIBLE WITH DAMAGING WINDS THE MOST LIKELY HAZARD. FREEZING LEVELS REMAIN QUITE HIGH...IN THE NEIGHBORHOOD OF 14KFT TO 15KFT...SO ONLY STORMS WITH DECENT STRUCTURE/ROTATION SHOULD POSE HAIL THREAT. ACTIVITY SHOULD SHIFT SOUTH OF OUR AREA A LITTLE AFTER 06Z TONIGHT AS FRONT SETTLES SOUTH...LEAVING THE REST OF THE NIGHT DRY. WITH LOWER DEW POINTS SPILLING INTO THE AREA COMBINED WITH LIGHT NORTHERLY WINDS...EXPECT LOWS TO DROP INTO THE LOWER 60S NORTH BUT HOLD IN THE LOWER 70S SOUTH. A SOMEWHAT COOLER AND DRIER COUPLE OF DAYS STILL LOOKS ON TRACK FOR WEDNESDAY AND THURSDAY AS DEW POINTS DROP CLOSER TO 60 THAN 70. HIGHS EACH DAY SHOULD HOLD IN THE MIDDLE 80S OR SO. HOWEVER SOUTH WINDS WILL RETURN FOR THURSDAY...SO AN INCREASE IN LOW LEVEL MOISTURE WILL BEGIN THEN. THERE IS ALSO A SMALL CHANCE FOR THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY MORNING...ESPECIALLY OVER OUR FAR SOUTHWEST CWA AND CENTRAL NEBRASKA...WHERE ZONE OF MID LEVEL WARM ADVECTION COULD TRIGGER ELEVATED STORMS. RIDGE BEGINS TO BUILD INTO THE REGION ON FRIDAY AND REMAINS OVER THE MIDDLE OF THE COUNTRY THROUGH NEXT WEEK. THIS SHOULD NORMALLY KEEP US DRY AND HOT...BUT ECMWF AND TO SOME EXTENT THE GFS SHOW A WEAKNESS IN THE RIDGE SUNDAY AND MONDAY THAT MAY ALLOW A SURFACE FRONT TO DRIFT INTO OUR AREA. CURRENTLY HAVE SMALL POPS DURING THIS TIME PERIOD...SO WILL NOT CHANGE AT THIS TIME. OTHERWISE EXPECT TEMPERATURES TO APPROACH OR EXCEED 90 MUCH OF THE PERIOD FRIDAY THROUGH TUESDAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1139 PM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 451 PM CDT TUE JUL 9 2013 DESPITE DECENT RECOVERY IN TEMPERATURES AFTER THE PASSAGE OF THE MORNING/MIDDAY CONVECTION...SUCH AS LA CROSSE CLIMBING UP TO 90F WITH A DEWPOINT OF 72F...CONVECTION IS DEFINITELY STRUGGLING. TWO THINGS ARE GOING ON HERE... 1. MASSIVE DRYING SEEN ON WATER VAPOR IN THE WAKE OF THE MORNING/MIDDAY CONVECTION AND ASSOCIATED MCV/SHORTWAVE TROUGH. THIS DRYING IMPLIES SUBSIDENCE. 2. A SURGE OF WARMER AIR AT 750MB ACCOMPANYING THE MASSIVE DRYING. THIS IS SEEN NICELY ON 20Z TAMDAR SOUNDINGS AT MPX AND DMX WHICH ARE 14C AND 16C RESPECTIVELY. THE LOWER TEMPERATURES AT MPX HAVE ALLOWED SOME CONVECTION TO FIRE NORTH OF LA CROSSE...HOWEVER...OVERALL THESE VALUES ARE PUTTING A CAP TO CONVECTION. MODIFYING A RAP SOUNDING AT 22Z FOR LA CROSSE WITH THE CURRENT SURFACE TEMP/DEWPOINTS AND A 16C 750MB TEMP STILL SHOWS A LITTLE CAPPING TO OVERCOME. ANTICIPATING LITTLE CHANGE IN CONVECTIVE ACTIVITY THROUGH THE NEXT COUPLE HOURS AS WE STAY IN THE SUBSIDENCE/DRYING ALOFT AND WARM 750MB AIR SPREADS EAST. ADDITIONALLY...WE WILL BE APPROACHING THE END OF HEATING SHORTLY...WHICH IN TURN WILL ONLY INCREASE THE CIN HEADING THROUGH THE EVENING. .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 250 PM CDT TUE JUL 9 2013 AN UPPER LEVEL SHORTWAVE TROUGH WAS TRACKING EAST ACROSS THE NORTHERN PLAINS THIS AFTERNOON...AND WILL WORK ACROSS NORTHERN PARTS OF THE REGION THIS EVENING. AHEAD OF THE UPPER LEVEL ENERGY AND AT THE SFC...AN ASSOCIATED FRONTAL BOUNDARY IS PROGGED TO MOVE OVER THE LOCAL FORECAST AREA BY 00Z...EXITING INTO EASTERN WI AFTER 06Z. MORNING/EARLY AFTERNOON CONVECTION HAS WORKED OVER THE ATMOSPHERE PRETTY GOOD...AND NOT A LOT OF TIME/SPACE TO RE-ESTABLISH SOME INSTABILITY AHEAD OF THE FRONT. MESO MODELS NOT BULLISH ON FIRING MUCH/IF ANY CONVECTION ALONG THE SFC BOUNDARY AS IT SWEEPS THROUGH THIS EVENING. THINK THIS IS THE WAY TO GO. THE CAVEAT...OF COURSE...IS IF THE ATMOSPHERE CAN JUICE BACK UP...THE STORM CHANCES WOULD INCREASE...AND THERE COULD BE A STRONG/SEVERE RISK. LATEST RADAR IMAGERY HAS SHOWN SOME DEVELOPMENT OVER NORTHWEST WI...ASSOCIATED WITH AN MCV FROM THE MORNING CONVECTION. NOT MUCH ELSEWHERE...ALTHOUGH SOME AGGRAVATED CU PER SATELLITE IMAGERY COULD EVENTUALLY BECOME SHOWERS/STORMS. WILL MONITOR TRENDS...BUT WILL STEER THE FORECAST FOR LESS PCPN CHANCES. HIGH PRESSURE STARTS TO BUILD IN FROM THE NORTHERN PLAINS ON WED...CLEARING OUT THE SKIES AND USHERING IN A MUCH COOLER AND DRIER AIRMASS. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 250 PM CDT TUE JUL 9 2013 HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE FOR THE REGION INTO FRIDAY...WITH RELATIVELY COOLER/LESS HUMID AIR FOR THE REST OF THE WORK WEEK. UPPER LEVEL SHORTWAVE TROUGH WILL DRIVE EASTWARD ACROSS SOUTHERN CANADA FOR THE UPCOMING WEEKEND. WHILE THE BULK OF THE UPPER LEVEL ENERGY WILL HOLD WELL NORTH OF THE LOCAL AREA...THIS SYSTEM WILL DRAG A SFC FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FRI NIGHT/SAT. THE GFS/ECMWF LAYS UP THE FRONT FROM WEST TO EAST AND HANGS IT ACROSS THE REGION INTO THE EARLY PART OF NEXT WEEK. GOOD LOW LEVEL MOISTURE RETURN INTO THE BOUNDARY WILL HELP FUEL SHOWERS/STORMS...WITH SOME INSTABILITY TO POWER STORMS. WIND SHEAR AT THIS TIME LOOKS MORE NORTH OF THE FRONT. THIS SCENARIO COULD BRING HEAVY RAINS TO PARTS OF THE REGION...WITH TRAINING STORMS AND A GOOD TAP INTO MOISTURE. THAT SAID...THERE IS UNCERTAINTY WITH WHERE THE FRONT WILL REST AND IF IT WAVERS NORTH-SOUTH. WILL STICK WITH A CONSENSUS/EC BLEND FOR THE RAIN CHANCES...FAVORING RAIN CHANCES TO THE NORTH. && .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 250 PM CDT TUE JUL 9 2013 AN UPPER LEVEL SHORTWAVE TROUGH WAS TRACKING EAST ACROSS THE NORTHERN PLAINS THIS AFTERNOON...AND WILL WORK ACROSS NORTHERN PARTS OF THE REGION THIS EVENING. AHEAD OF THE UPPER LEVEL ENERGY AND AT THE SFC...AN ASSOCIATED FRONTAL BOUNDARY IS PROGGED TO MOVE OVER THE LOCAL FORECAST AREA BY 00Z...EXITING INTO EASTERN WI AFTER 06Z. MORNING/EARLY AFTERNOON CONVECTION HAS WORKED OVER THE ATMOSPHERE PRETTY GOOD...AND NOT A LOT OF TIME/SPACE TO RE-ESTABLISH SOME INSTABILTY AHEAD OF THE FRONT. MESO MODELS NOT BULLISH ON FIRING MUCH/IF ANY CONVECTION ALONG THE SFC BOUNDARY AS IT SWEEPS THROUGH THIS EVENING. THINK THIS IS THE WAY TO GO. THE CAVEAT...OF COURSE...IS IF THE ATMOSPHERE CAN JUICE BACK UP...THE STORM CHANCES WOULD INCREASE...AND THERE COULD BE A STRONG/SEVERE RISK. LATEST RADAR IMAGERY HAS SHOWN SOME DEVELOPMENT OVER NORTHWEST WI...ASSOCIATED WITH AN MCV FROM THE MORNING CONVECTION. NOT MUCH ELSEWHERE...ALTHOUGH SOME AGGRAVATED CU PER SATELLITE IMAGERY COULD EVENTUALLY BECOME SHOWERS/STORMS. WILL MONITOR TRENDS...BUT WILL STEER THE FORECAST FOR LESS PCPN CHANCES. HIGH PRESSURE STARTS TO BUILD IN FROM THE NORTHERN PLAINS ON WED...CLEARING OUT THE SKIES AND USHERING IN A MUCH COOLER AND DRIER AIRMASS. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 250 PM CDT TUE JUL 9 2013 HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE FOR THE REGION INTO FRIDAY...WITH RELATIVELY COOLER/LESS HUMID AIR FOR THE REST OF THE WORK WEEK. UPPER LEVEL SHORTWAVE TROUGH WILL DRIVE EASTWARD ACROSS SOUTHERN CANADA FOR THE UPCOMING WEEKEND. WHILE THE BULK OF THE UPPER LEVEL ENERGY WILL HOLD WELL NORTH OF THE LOCAL AREA...THIS SYSTEM WILL DRAG A SFC FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FRI NIGHT/SAT. THE GFS/ECMWF LAYS UP THE FRONT FROM WEST TO EAST AND HANGS IT ACROSS THE REGION INTO THE EARLY PART OF NEXT WEEK. GOOD LOW LEVEL MOISTURE RETURN INTO THE BOUNDARY WILL HELP FUEL SHOWERS/STORMS...WITH SOME INSTABILITY TO POWER STORMS. WIND SHEAR AT THIS TIME LOOKS MORE NORTH OF THE FRONT. THIS SCENARIO COULD BRING HEAVY RAINS TO PARTS OF THE REGION...WITH TRAINING STORMS AND A GOOD TAP INTO MOISTURE. THAT SAID...THERE IS UNCERTAINTY WITH WHERE THE FRONT WILL REST AND IF IT WAVERS NORTH-SOUTH. WILL STICK WITH A CONSENSUS/EC BLEND FOR THE RAIN CHANCES...FAVORING RAIN CHANCES TO THE NORTH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1139 PM CDT TUE JUL 9 2013 MAIN AVIATION CONCERN IS WINDS. A COLD FRONT STRETCHING FROM NEAR EAU CLAIRE WI TO MANKATO MN AT 05Z WILL MOVE THROUGH THE TAF SITES DURING THE NEXT FEW HOURS... SWINGING WINDS AROUND TO THE NORTHWEST AND MAINTAINING A BREEZE AROUND 10 KT. WINDS COULD GUST BRIEFLY WITH THE PASSAGE... ESPECIALLY AT KRST AND INCLUDED A TEMPO GROUP FROM 06-08Z THERE FOR GUSTS OF 23 KT. GUSTS ARE EXPECTED AT BOTH TAF SITES DURING THE DAYTIME HOURS WITH A TIGHT PRESSURE GRADIENT IN PLACE AHEAD OF HIGH PRESSURE BUILDING EAST FROM THE DAKOTAS. THESE GUSTS SHOULD RANGE FROM 15-20 KT. PLAN ON THE WINDS TO DIMINISH THROUGH THE EVENING AS DAYTIME MIXING SUBSIDES AND THE HIGH MOVES CLOSER. DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE ACCOMPANYING THE HIGH PRESSURE AREA WILL HELP TO KEEP CONDITIONS VFR THROUGH THE TAF PERIOD. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...AJ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
637 AM CDT WED JUL 10 2013 .AVIATION... PREVALENT VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. CONVECTION IN SOUTHERN MISSOURI CONTINUES TO SLOWLY MOVE SOUTH AHEAD OF A FRONTAL BOUNDARY. THIS WILL DIMINISH SOMEWHAT IN THE NEXT FEW HOURS... BUT ADDITIONAL DEVELOPMENT WILL BE POSSIBLE LATER THIS MORNING AND INTO THE AFTERNOON HOURS. AT THIS POINT...HAVE CONTINUED TO MENTION VCTS IN THE NORTHERN SITES...BUT AS FOR THE CENTRAL AND SOUTH... NOT TOO CONFIDENT YET IF PRECIP WILL BE SEEN AT ALL...GIVEN THE EXPECTED SCATTERED NATURE OF THE PRECIP LATER TODAY. TAFS ALREADY OUT. && .PREV DISCUSSION... /ISSUED 331 AM CDT WED JUL 10 2013/ SHORT TERM...TODAY THROUGH SATURDAY NIGHT CONVECTION WAS ONGOING ACROSS PARTS OF SOUTHERN/CENTRAL MISSOURI EARLY THIS MORNING. FURTHER NORTH A FRONTAL BOUNDARY STRETCHED ACROSS NORTHERN KANSAS AND UP INTO SOUTHEASTERN IOWA. THE FORECAST TODAY IS SOMEWHAT TRICKY AS A RESULT OF THESE TWO FEATURES. THE ONGOING CONVECTION HAS SENT OUT SOME OUTFLOW BOUNDARIES THAT SHOULD WORK INTO NRN ARKANSAS BY MID MORNING. THE 4KM WRF AND ALSO THE RAPID REFRESH RUC SUGGEST THESE BOUNDARIES WILL LIKELY BE A FOCUS FOR MIDDAY AND AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY SOUTH OF THE I-40 CORRIDOR. HOWEVER THE FRONTAL BOUNDARY WILL MOVE IN DURING THE EVENING HOURS...UPON WHICH THE MORE COARSE MODELS SUGGEST WILL BE MORE DOMINANT SHOWER/THUNDERSTORM ACTIVITY. TRENDED THE FORECAST IN THE DIRECTION OF THE FORMER...WITH SLIGHTLY COOLER /WE ARE TALKING ABOUT 1-2 DEGREES HERE/ AFTERNOON HIGHS UP NORTH THAN GUIDANCE SUGGESTS...AND PLAYED RAIN CHANCES TOWARDS THE SOUTHERN ISOLD TO SCT VARIETY INSTEAD OF CONVECTION BEING TIED TO THE FRONT. THAT SAID...DID LEAVE SLIGHT CHANCES IN THE NORTH THROUGH THE DAY AND INTO TONIGHT TO ACCOUNT FOR CONVECTION ALONG THE FRONT. OTHERWISE...NOT MUCH TO TALK ABOUT IN THE EXTENDED. THE AFOREMENTIONED FRONT WILL PUSH WELL INTO THE STATE BY THURSDAY. UPPER LEVEL HIGH PRESSURE SITUATED OVER THE PLAINS WILL BECOME HIGHLY AMPLIFIED BY LATE THURSDAY. LEFT SOME SLIGHT RAIN CHANCES OVER THE FAR SOUTH AND FAR SOUTHWEST PARTS OF THE FORECAST AREA THU AND FRI AFTERNOONS. THERE IS SOME QPF SIGNAL IN NUMERICAL MODELS BOTH DAYS IN THOSE REGIONS...WHICH SEEMS REASONABLE. TEMPERATURES WILL NOT COOL DOWN MUCH IN THE SOUTHWEST...BUT HIGHS IN THE NORTHEAST BY FRIDAY WILL LIKELY NOT REACH 90 DEGREES. HOWEVER DRIER AIR WILL FILTER IN ACROSS ARKANSAS SO EVEN WITH HIGHS IN THE LOW 90S ACROSS THE SOUTHWEST HALF OF THE STATE...THERE WILL BE SOME RELIEF FROM THE HOT AND MUGGY CONDITIONS HEADING INTO THE WEEKEND. LONG TERM...SATURDAY NIGHT THROUGH TUESDAY THE LONG TERM OFFERS AN ODD SYNOPTIC SETUP FOR JULY. AT THE BEGINNING...THE RETROGRADING CUTOFF LOW WILL BE MOVING INTO COASTAL TEXAS...WITH AN ELONGATED UPPER RIDGE SETTING UP OVER THE PLAINS. THE AFOREMENTIONED LOW WILL BRING MOISTURE UP INTO THE REGION...AND WITH IT A CHANCE OF SHOWERS/STORMS EACH DAY...WHICH SHOULD MOSTLY BE DIURNALLY DRIVEN. WILL CONTINUE TO KEEP RAIN CHANCES SMALL TO ACCOUNT FOR UNCERTAINTIES WITH THIS SETUP. IF YOU CAN BELIEVE YOUR EYES...THE EXACT SAME THING LOOKS TO HAPPEN BY LATE MONDAY INTO TUESDAY...AS THE MODELS ADVERTISE ANOTHER CUTOFF UPPER LOW FORMING AND RETROGRADING TOWARD THE MID SOUTH REGION. THIS WILL BRING A REINFORCING SHOT OF AT LEAST SMALL RAIN CHANCES TO END THE PERIOD. INITIALLY...TEMPERATURES WILL BE A LITTLE BELOW SEASONAL AVERAGES DUE TO EASTERLY SURFACE FLOW. BY MONDAY AND TUESDAY...TEMPERATURES WILL BE A BIT WARMER...BUT WILL BE KEPT IN CHECK BY CLOUD COVER ASSOCIATED WITH THE UPPER LOWS. && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AVIATION...57
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
501 AM MST WED JUL 10 2013 .UPDATE...UPDATED AVIATION AND FIRE WX DISCUSSIONS. && .SYNOPSIS... A MUCH MORE FAVORABLE SOUTHEASTERLY FLOW WILL CONTINUE TO IMPORT DEEPER MONSOON MOISTURE INTO THE REGION OVER THE NEXT COUPLE DAYS. THIS WILL LEAD TO AN APPRECIABLE INCREASE IN SHOWERS AND THUNDERSTORMS ACROSS THE ENTIRE AREA THAT WILL LAST THROUGH FRIDAY. THE INCREASED MOISTURE WILL ALSO RESULT IN COOLER DAYTIME TEMPERATURES FOR THE REST OF THE WORK WEEK. WARMER TEMPERATURES AND A GENERAL DECREASE IN THUNDERSTORM ACTIVITY CAN BE EXPECTED OVER THE WEEKEND...HOWEVER A RETURN TO AN ACTIVE MONSOON PERIOD IS LIKELY AGAIN EARLY NEXT WEEK. && .DISCUSSION... A PARADE OF INVERTED TROUGHS/CIRCULATION CENTERS CONTINUES TO MARCH WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL HIGH CENTERED OVER WEST TEXAS THIS MORNING. THE MOST IMPRESSIVE WAVE NEAR 28N 108W HAS SUPPORTED AN IMPRESSIVE MCS OVER NORTHERN MEXICO FEEDING ON MUCAPES OVER 1000 J/KG AND PWATS EXCEEDING 2.0 INCHES. CLOUDS TOPS HAVE RAPIDLY WARMED IN THE PAST HOUR WITH A NOTABLE RAPID DECREASE IN LIGHTNING ACTIVITY...SIGNALING A DOWNTREND IN CONVECTIVE STRENGTH. NEVERTHELESS...OUTFLOWS...GRAVITY WAVES...AND INFUSION/ADVECTION OF MOISTURE INTO THE MID LEVELS HAS ALLOWED SHOWERS TO DEVELOP OVER PARTS OF CENTRAL AND SOUTHWEST ARIZONA OVERNIGHT. SOME STRONGER WIND GUSTS HAVE ALSO BEEN OBSERVED WITH THIS ACTIVITY BEHIND OUTFLOW BOUNDARIES...AND EXPECTING THIS TREND WILL CONTINUE FOR THE NEXT SEVERAL HOURS BEFORE THE ENTIRE SYSTEM DECAYS. RECENT HRRR OUTPUT HAS BEST CAPTURED RADAR TRENDS...AND HAVE TAILORED SLIGHT CHANCE SHOWER POPS BASED IN ITS OUTPUT THROUGH THE MID MORNING AS ACTIVITY WANES. SEVERAL FACETS OF THE FORECAST SUGGEST LATE THIS AFTERNOON...AND PARTICULARLY THIS EVENING AND OVERNIGHT WILL BECOME QUITE ACTIVE OVER MUCH OF THE FORECAST AREA. FIRST...THE PRESENCE OF THE SONORAN INVERTED TROUGH SHOULD PROVIDE AMPLE DIFLUENCE ALOFT SUPPORTIVE FOR CONVECTIVE SUSTENANCE. SECOND...A TONGUE OF RICH MOISTURE SHOULD BE ADVECTED NORTHWEST THROUGHOUT THE DAY...AS EVIDENCED BY OBJECTIVE ANALYSIS OF +10C H7 DEWPOINTS AND +15C H8 DEWPOINTS LURKING IN SOUTHEAST ARIZONA (TRANSLATING TO DEEP 11-12 G/KG MIXING RATIOS). THERE IS ALSO SLIGHTLY COOLER TEMPERATURES IN THIS LAYER WHICH WILL GRADUALLY ERODE THE CAPPING INVERSION NEAR THE H7 LAYER. FORECAST SOUNDINGS INDICATE INSTABILITY BECOMING MAXIMIZED AOA 750 J/KG DURING PEAK HEATING WITH INHIBITION SLOWLY ERODING. HRRR AND HIGH RESOLUTION WRF NMM CORES (AND TO SOME EXTENT THE COARSER GFS) ARE IN GENERAL AGREEMENT OF A MORE CLASSIC MONSOON PATTERN OF CONVERGENT CONVECTIVE COMPLEXES FROM BOTH THE MOGOLLON RIM AND SERN ARIZONA PROGRESSING THROUGH LOWER ELEVATIONS WESTWARD TO THE COLORADO RIVER VALLEY THROUGHOUT THE EVENING AND OVERNIGHT. ON THE OTHER HAND...ARW CORES AND THE ECMWF ARE NOT AS BULLISH WITH THE MAINTENANCE OF CONVECTION TONIGHT. REGARDLESS...CONCEPTUALLY THE CURRENT PATTERN FAVORS AT LEAST A PARTIALLY ACTIVE DAY...IF NOT VERY ACTIVE...THOUGH ENOUGH UNCERTAINTY EXISTS TO PRECLUDE UNUSUALLY HIGH POPS. ANY STRONGER THUNDERSTORM WILL INITIALLY HAVE THE POSSIBILITY OF PRODUCING SEVERE WIND GUSTS AND DENSE BLOWING DUST AS T/TD SPREADS WILL BE ABOVE 40F...THOUGH AS ACTIVITY EVOLVES OVERNIGHT AND THE ATMOSPHERIC PROFILE BECOME MORE MOIST...THE THREAT SHOULD TRANSITION TO MORE OF A HEAVY RAIN THREAT (THOUGH STRONGER WINDS STILL CANNOT BE DISCOUNTED). LARGE UNCERTAINTY EXISTS REGARDING THE PROCESSION OF TEMPERATURES AND CONVECTIVE THREAT THURSDAY...PRIMARILY DEPENDENT ON THE ANTECEDENT CONDITIONS AND ACTIVITY WEDNESDAY NIGHT. SOME MODEL FORECASTS SUGGEST THURSDAY MAY BE ONE OF THOSE RARE SUMMER DAYS SOCKED IN WITH CLOUDS...UNUSUALLY COOL TEMPERATURES...AND LITTLE AVAILABLE INSTABILITY. HOWEVER...IF CLOUDS BEGIN TO CLEAR DURING PEAK HEATING IT WILL TAKE ONLY A FEW HOURS TO REALIZE MLCAPES ABOVE 1000 J/KG COINCIDENT WITH AMPLE SHEAR AND MOISTURE PROFILES. KEPT POPS GENERALLY IN THE 30 PERCENT CHANCE CATEGORY GIVEN THE OVERALL LOW CONFIDENCE FORECAST...THOUGH IF ORGANIZED CONVECTION DOES FORM IMPACTS COULD BE SIGNIFICANT. REGARDLESS...IT APPEARS TEMPERATURES WILL STAY IN A BELOW NORMAL CATEGORY (WHETHER A FEW DEGREES OR 10+ DEGREES BELOW REMAINS TO BE SEEN). FRIDAY COULD BE A SLOWER CONVECTIVE DAY IF THURSDAY ENDS UP BEING AN ACTIVE MONSOON DAY...OR VICE VERSA COULD BE ACTIVE IF THURSDAY REMAINS CONTAMINATED AND THE POSSIBILITY OF ANOTHER INVERTED TROUGH ROTATING WESTWARD FROM THE GULF OF MEXICO CAN COME TO FRUITION. AMPLE MONSOON MOISTURE WILL STILL BE IN PLACE SUCH THAT AREAWIDE SLIGHT CHANCE TO CHANCE POPS ARE STILL WARRANTED...THOUGH THE TREND WAS TO TEMPER POPS SOMEWHAT. AS THE WEST TEXAS SUBTROPICAL HIGH BEGINS TO STRENGTHEN...EXPAND...AND RETROGRADE WESTWARD...THERE SHOULD BE A GRADUAL DECREASE IN MOISTURE OVER THE WEEKEND NECESSITATING LOWER PRECIPITATION CHANCES IN THE FORECAST. AS THE MOISTURE DECREASES...TEMPERATURES WILL REBOUND WITH HIGHS RETURNING TO ABOVE NORMAL LEVELS. MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT DEPICTING A VERY WELL DEFINED INVERTED TROUGH/CIRCULATION CENTER HEADED DIRECTLY TOWARDS ARIZONA EARLY NEXT WEEK. MOISTURE WILL LIKELY SURGE BACK NORTH INTO THE REGION AHEAD OF THIS SYSTEM...WHILE DYNAMIC SUPPORT INCREASES. THIS COULD VERY WELL SIGNAL THE START OF ANOTHER MULTI-DAY ACTIVE PERIOD...AND HAVE STARTED TRENDING DAYTIME TEMPERATURES LOWER AND POPS HIGHER. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... FAIRLY STRONG WESTERLY LOW LEVEL FLOW HAS PERSISTED OVERNIGHT KEEPING DRAINAGE WINDS AT BAY...AND WILL LIKELY CONTINUE TO DO SO FOR THE REST OF THIS MORNING. BY THE LATE AFTERNOON...WESTERLY WINDS ARE EXPECTED TO INCREASE WITH GUSTS AROUND 20 KTS. THIS EVENING COULD BRING SCATTERED TO POSSIBLY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...POTENTIALLY LASTING INTO THE OVERNIGHT HOURS. SOME THUNDERSTORMS COULD BE STRONG...AND CAN/T RULE OUT THE CHANCE OF STRONG WIND GUSTS AND BLOWING DUST AFFECTING AREA TAF SITES. CONFIDENCE IN TIMING AND EVOLUTION OF THIS EVENT IS SOMEWHAT ON THE LOW SIDE...BUT IT IS LOOKING LIKE THIS WILL BE THE FIRST MAJOR MONSOON DAY FOR THE LOWER DESERTS SO FAR THIS SUMMER. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... BROKEN HIGH CLOUDS WILL PERSIST THROUGH THE MORNING HOURS ALONG WITH CONTINUED BREEZY SOUTHERLY WINDS. EXPECTING VERY SLIM STORM/RAIN CHANCES FOR THE TAF PERIOD...HOWEVER BREEZY OUTFLOW WINDS AND ACCOMPANYING DUST MAY MOVE INTO THE REGION STARTING THIS EVENING FROM STORMS OVER ARIZONA AND NORTHERN MEXICO. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL REMAIN INTO THE EARLY WEEKEND...BUT A DRYING TREND WILL KEEP STORMS MAINLY CONFINED TO THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX SUNDAY AND MONDAY. THE DRYING TREND WILL BRING MINIMUM HUMIDITIES INTO THE TEENS ACROSS THE LOWER DESERTS FOR SUNDAY AND MONDAY. OTHER DAYS WILL GENERALLY SEE AFTERNOON MINIMUM VALUES ONLY DROPPING INTO THE 20-30 PERCENT RANGE. OVERNIGHT RECOVERY SHOULD BE GOOD TO EXCELLENT WITH READINGS CLIMBING ABOVE 40 PERCENT MOST NIGHTS. GUSTY WINDS ARE POSSIBLE EACH DAY...AS OUTFLOW BOUNDARIES PROPAGATE AWAY FROM DEVELOPING SHOWERS AND THUNDERSTORMS. && $$ .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MO AVIATION...KUHLMAN FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
335 AM MST WED JUL 10 2013 .SYNOPSIS... A MUCH MORE FAVORABLE SOUTHEASTERLY FLOW WILL CONTINUE TO IMPORT DEEPER MONSOON MOISTURE INTO THE REGION OVER THE NEXT COUPLE DAYS. THIS WILL LEAD TO AN APPRECIABLE INCREASE IN SHOWERS AND THUNDERSTORMS ACROSS THE ENTIRE AREA THAT WILL LAST THROUGH FRIDAY. THE INCREASED MOISTURE WILL ALSO RESULT IN COOLER DAYTIME TEMPERATURES FOR THE REST OF THE WORK WEEK. WARMER TEMPERATURES AND A GENERAL DECREASE IN THUNDERSTORM ACTIVITY CAN BE EXPECTED OVER THE WEEKEND...HOWEVER A RETURN TO AN ACTIVE MONSOON PERIOD IS LIKELY AGAIN EARLY NEXT WEEK. && .DISCUSSION... A PARADE OF INVERTED TROUGHS/CIRCULATION CENTERS CONTINUES TO MARCH WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL HIGH CENTERED OVER WEST TEXAS THIS MORNING. THE MOST IMPRESSIVE WAVE NEAR 28N 108W HAS SUPPORTED AN IMPRESSIVE MCS OVER NORTHERN MEXICO FEEDING ON MUCAPES OVER 1000 J/KG AND PWATS EXCEEDING 2.0 INCHES. CLOUDS TOPS HAVE RAPIDLY WARMED IN THE PAST HOUR WITH A NOTABLE RAPID DECREASE IN LIGHTNING ACTIVITY...SIGNALING A DOWNTREND IN CONVECTIVE STRENGTH. NEVERTHELESS...OUTFLOWS...GRAVITY WAVES...AND INFUSION/ADVECTION OF MOISTURE INTO THE MID LEVELS HAS ALLOWED SHOWERS TO DEVELOP OVER PARTS OF CENTRAL AND SOUTHWEST ARIZONA OVERNIGHT. SOME STRONGER WIND GUSTS HAVE ALSO BEEN OBSERVED WITH THIS ACTIVITY BEHIND OUTFLOW BOUNDARIES...AND EXPECTING THIS TREND WILL CONTINUE FOR THE NEXT SEVERAL HOURS BEFORE THE ENTIRE SYSTEM DECAYS. RECENT HRRR OUTPUT HAS BEST CAPTURED RADAR TRENDS...AND HAVE TAILORED SLIGHT CHANCE SHOWER POPS BASED IN ITS OUTPUT THROUGH THE MID MORNING AS ACTIVITY WANES. SEVERAL FACETS OF THE FORECAST SUGGEST LATE THIS AFTERNOON...AND PARTICULARLY THIS EVENING AND OVERNIGHT WILL BECOME QUITE ACTIVE OVER MUCH OF THE FORECAST AREA. FIRST...THE PRESENCE OF THE SONORAN INVERTED TROUGH SHOULD PROVIDE AMPLE DIFLUENCE ALOFT SUPPORTIVE FOR CONVECTIVE SUSTENANCE. SECOND...A TONGUE OF RICH MOISTURE SHOULD BE ADVECTED NORTHWEST THROUGHOUT THE DAY...AS EVIDENCED BY OBJECTIVE ANALYSIS OF +10C H7 DEWPOINTS AND +15C H8 DEWPOINTS LURKING IN SOUTHEAST ARIZONA (TRANSLATING TO DEEP 11-12 G/KG MIXING RATIOS). THERE IS ALSO SLIGHTLY COOLER TEMPERATURES IN THIS LAYER WHICH WILL GRADUALLY ERODE THE CAPPING INVERSION NEAR THE H7 LAYER. FORECAST SOUNDINGS INDICATE INSTABILITY BECOMING MAXIMIZED AOA 750 J/KG DURING PEAK HEATING WITH INHIBITION SLOWLY ERODING. HRRR AND HIGH RESOLUTION WRF NMM CORES (AND TO SOME EXTENT THE COARSER GFS) ARE IN GENERAL AGREEMENT OF A MORE CLASSIC MONSOON PATTERN OF CONVERGENT CONVECTIVE COMPLEXES FROM BOTH THE MOGOLLON RIM AND SERN ARIZONA PROGRESSING THROUGH LOWER ELEVATIONS WESTWARD TO THE COLORADO RIVER VALLEY THROUGHOUT THE EVENING AND OVERNIGHT. ON THE OTHER HAND...ARW CORES AND THE ECMWF ARE NOT AS BULLISH WITH THE MAINTENANCE OF CONVECTION TONIGHT. REGARDLESS...CONCEPTUALLY THE CURRENT PATTERN FAVORS AT LEAST A PARTIALLY ACTIVE DAY...IF NOT VERY ACTIVE...THOUGH ENOUGH UNCERTAINTY EXISTS TO PRECLUDE UNUSUALLY HIGH POPS. ANY STRONGER THUNDERSTORM WILL INITIALLY HAVE THE POSSIBILITY OF PRODUCING SEVERE WIND GUSTS AND DENSE BLOWING DUST AS T/TD SPREADS WILL BE ABOVE 40F...THOUGH AS ACTIVITY EVOLVES OVERNIGHT AND THE ATMOSPHERIC PROFILE BECOME MORE MOIST...THE THREAT SHOULD TRANSITION TO MORE OF A HEAVY RAIN THREAT (THOUGH STRONGER WINDS STILL CANNOT BE DISCOUNTED). LARGE UNCERTAINTY EXISTS REGARDING THE PROCESSION OF TEMPERATURES AND CONVECTIVE THREAT THURSDAY...PRIMARILY DEPENDENT ON THE ANTECEDENT CONDITIONS AND ACTIVITY WEDNESDAY NIGHT. SOME MODEL FORECASTS SUGGEST THURSDAY MAY BE ONE OF THOSE RARE SUMMER DAYS SOCKED IN WITH CLOUDS...UNUSUALLY COOL TEMPERATURES...AND LITTLE AVAILABLE INSTABILITY. HOWEVER...IF CLOUDS BEGIN TO CLEAR DURING PEAK HEATING IT WILL TAKE ONLY A FEW HOURS TO REALIZE MLCAPES ABOVE 1000 J/KG COINCIDENT WITH AMPLE SHEAR AND MOISTURE PROFILES. KEPT POPS GENERALLY IN THE 30 PERCENT CHANCE CATEGORY GIVEN THE OVERALL LOW CONFIDENCE FORECAST...THOUGH IF ORGANIZED CONVECTION DOES FORM IMPACTS COULD BE SIGNIFICANT. REGARDLESS...IT APPEARS TEMPERATURES WILL STAY IN A BELOW NORMAL CATEGORY (WHETHER A FEW DEGREES OR 10+ DEGREES BELOW REMAINS TO BE SEEN). FRIDAY COULD BE A SLOWER CONVECTIVE DAY IF THURSDAY ENDS UP BEING AN ACTIVE MONSOON DAY...OR VICE VERSA COULD BE ACTIVE IF THURSDAY REMAINS CONTAMINATED AND THE POSSIBILITY OF ANOTHER INVERTED TROUGH ROTATING WESTWARD FROM THE GULF OF MEXICO CAN COME TO FRUITION. AMPLE MONSOON MOISTURE WILL STILL BE IN PLACE SUCH THAT AREAWIDE SLIGHT CHANCE TO CHANCE POPS ARE STILL WARRANTED...THOUGH THE TREND WAS TO TEMPER POPS SOMEWHAT. AS THE WEST TEXAS SUBTROPICAL HIGH BEGINS TO STRENGTHEN...EXPAND...AND RETROGRADE WESTWARD...THERE SHOULD BE A GRADUAL DECREASE IN MOISTURE OVER THE WEEKEND NECESSITATING LOWER PRECIPITATION CHANCES IN THE FORECAST. AS THE MOISTURE DECREASES...TEMPERATURES WILL REBOUND WITH HIGHS RETURNING TO ABOVE NORMAL LEVELS. MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT DEPICTING A VERY WELL DEFINED INVERTED TROUGH/CIRCULATION CENTER HEADED DIRECTLY TOWARDS ARIZONA EARLY NEXT WEEK. MOISTURE WILL LIKELY SURGE BACK NORTH INTO THE REGION AHEAD OF THIS SYSTEM...WHILE DYNAMIC SUPPORT INCREASES. THIS COULD VERY WELL SIGNAL THE START OF ANOTHER MULTI-DAY ACTIVE PERIOD...AND HAVE STARTED TRENDING DAYTIME TEMPERATURES LOWER AND POPS HIGHER. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... ELEVATED WESTERLY SURFACE FLOW WILL PERSIST FOR THE PHX TERMINALS THROUGH MUCH OF THE EVENING AND EARLY MORNING HOURS. LARGE AREA OF STORM ACTIVITY WELL TO OUR SOUTH ALONG THE INTL BORDER MAY SEND BREEZY SOUTH WINDS...POTENTIAL FOR LOFTED DUST AND DEBRIS CLOUDS TO THE REGION BY THE SUNRISE. CONFIDENCE AT THIS TIME IS TOO LOW TO INCLUDE ANY WIND HEADING CHANGES OR CIGS BELOW 10K AGL IN THE 06Z TAF PACKAGE. STRAY SHOWER DEVELOPMENT ACROSS THE METRO COULD OCCUR OVERNIGHT...MOSTLY REMAINING HIGH BASED WITH LITTLE MEASURABLE PRECIP BUT POTENTIAL FOR BREEZY BUT ERRATIC WINDS IN THE VICINITY OF THE TERMINALS. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... SCT-BKN HIGH CLOUDS WILL PERSIST OVERNIGHT AS WILL CONTINUED BREEZY SOUTHEASTERLY WINDS. VERY SLIM STORM/RAIN CHANCES CONTINUE TO REMAIN FOR THE TAF PERIOD...HOWEVER BREEZY OUTFLOW WINDS AND ACCOMPANYING DUST MAY MOVE INTO THE REGION FROM MEXICO AND THE GULF OF CALIFORNIA IN THE EARLY MORNING HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... THURSDAY THROUGH MONDAY... THERE WILL BE AN INCREASED LIKELIHOOD OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...AS MOISTURE INCREASES ACROSS THE FORECAST AREA. THIS WILL ALSO MEAN INCREASED HUMIDITY...WITH AFTERNOON MINIMUM VALUES GENERALLY ONLY DROPPING INTO THE 20-30 PERCENT RANGE. OVERNIGHT RECOVERY SHOULD BE GOOD TO EXCELLENT WITH READINGS CLIMBING ABOVE 40 PERCENT MOST NIGHTS. SOME DRYING IS EXPECTED SUNDAY INTO MONDAY. GUSTY WINDS ARE POSSIBLE EACH DAY...AS OUTFLOW BOUNDARIES PROPAGATE AWAY FROM DEVELOPING SHOWERS AND THUNDERSTORMS. && $$ .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MO AVIATION...NOLTE FIRE WEATHER...MCLANE/LEINS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1130 AM EDT WED JUL 10 2013 .UPDATE... 15Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUES TO SHOW AN UPPER LEVEL PATTERN OVER THE CONUS DOMINATED BY A PROGRESSIVE NORTHERN STREAM FLOW ALONG THE U.S/CANADIAN BORDER OVER-TOP AN AN ELONGATED AND BROAD WEST TO EAST ORIENTED RIDGE. OTHER FEATURE OF NOTE REMAINS A WEAKENING TUTT FEATURE/UPPER LOW MIGRATING WESTWARD OVER SOUTH FL/FLORIDA STRAITS. THIS FEATURE LOOKS TO HAVE LIMITED IMPACT ON OUR WEATHER OTHER THAN SOME INCREASE IN COLUMN MOISTURE...AND MAINLY FOR THE SOUTHERN HALF OF OUR AREA. AT THIS POINT...THE THERMAL ANOMALY NORMALLY ASSOCIATED WITH TUTT CELLS THAT CAN ENHANCE INSTABILITY OVER LAND HAS ESSENTIALLY COLLAPSED...AND ANY INFLUENCE IT CAN STILL HAVE WILL BE FELT MAINLY OVER FAR SOUTHERN PORTIONS OF THE PENINSULA. AT THE SURFACE...LOCAL REGION IS EXPERIENCING A WEAK GRADIENT JUST TO THE SOUTH OF A BROAD SURFACE RIDGE AXIS EXTENDING FROM THE NORTH-CENTRAL GULF OF MEXICO TO NORTHERN FLORIDA AND THE GA/SC COAST. THIS WEAK GRADIENT WILL ALLOW FOR THE WEST-COAST SEA-BREEZE TO POTENTIALLY MIGRATE A BIT FURTHER INLAND THROUGH THE EARLY/MID AFTERNOON. HOWEVER...THE RESIDUAL LIGHT EASTERLY FLOW WILL STILL EVENTUALLY RESULT IN A WEST COAST DOMINANT CONVECTIVE PATTERN. HI-RESOLUTION CONVECTIVE ALLOWING MODEL SUITE ALL SHOW CONVECTION INITIATING FIRST DOWN TOWARD FT. MYERS AND THEN "RIPPLING" NORTHWARD UP THE COAST. POP FORECAST WILL FOLLOW THIS TREND WITH HIGHEST RAIN CHANCES THROUGH MID AFTERNOON OVER THE FAR SOUTHERN ZONES...AND THEN INCREASING LATE AFTERNOON/EVENING FURTHER NORTH TOWARD TAMPA BAY AND THE NATURE COAST. WET MICROBURST POTENTIAL HAS DECREASED FOR MAJORITY OF THE AREA WITH HIGHER VALUES OF THETA-E NOW FORECAST/OBSERVED AROUND 10-15KFT. 12Z NAM STILL SHOWED A DECENT PROFILE FOR WET-MICROBURST OVER THE NORTHERN NATURE COAST ZONES (CITRUS/LEVY) LATER THIS AFTERNOON AND WILL NEED TO KEEP A CLOSE EYE ON ANY STRONGER STORMS THAT FORM IN THIS VICINITY. ELSEWHERE APPEARS HEAVIER RAINFALL AND FREQUENT LIGHTNING WILL BE THE MAIN THREATS. BASED ON THE 12Z KTBW SOUNDING...STORM MOTION TODAY ONCE FULLY MATURE WOULD BE TOWARD THE WEST OR WEST-SW. TONIGHT... EVENING STORMS DISSIPATE BY 02-03Z OR TRANSLATE OFFSHORE WITH TIME. WEAK LEFTOVER VORTICITY LOBE FROM THE DECAYING TUTT IS FORECAST TO RESIDE ALONG THE FLORIDA WEST COAST LATE TONIGHT INTO THURSDAY MORNING. THIS WEAK CYCLONIC FLOW...AND ANY ASSOCIATED WEAK SURFACE REFECTION/TROUGH FEATURE WOULD LIKELY ENHANCE THE NOCTURNAL STORM POTENTIAL OVER THE COASTAL WATERS. MID-LEVEL FLOW IS ALSO PROGGED BY LATEST NUMERICAL GUIDANCE TO COME AROUND TO A MORE SOUTHERLY DIRECTION EARLY THURSDAY MORNING. THIS STEERING FLOW (IF DEVELOPING QUICKLY ENOUGH) SHOULD RESULT IN SOME OF THIS NOCTURNAL MARINE CONVECTION MIGRATING BACK TOWARD THE IMMEDIATE COAST AROUND DAWN AND INTO AT LEAST THE FIRST FEW DAYLIGHT HOURS. ONCE AGAIN CONVECTION ALLOWING GUIDANCE AND PARAMETRIZED GUIDANCE ALIKE ARE ALL SHOWING THIS POTENTIAL FOR COASTAL SHOWERS/STORM TOMORROW MORNING. CURRENT GRIDS SHOW CHANCE POPS ALONG THE IMMEDIATE COAST DURING THE MORNING ON THURSDAY...AND SEE LITTLE REASON FOR SIGNIFICANT UPDATES TO THIS INHERITED FORECAST. && .AVIATION... VFR CONDITIONS WITH VCNTY SHRA EARLY AFTERNOON AND VCNTY TSRA LATER. LCL MVFR/IFR AS CONVECTION CONTINUES UNTIL JUST AFTER SUNSET. LIGHT VARIABLE/EASTERLY WINDS SHIFT TO ONSHORE ALONG THE COAST IN THE AFTERNOON. && .MARINE... ALL EYES ON THE TROPICS FOR THE MARINE FORECAST. CURRENTLY...CHANTAL IS TRENDING WEAKER AND FURTHER WEST. WILL NEED TO MONITOR SITUATION AS GUIDANCE IS SPREAD INTO THE LONG TERM. IN GENERAL...HIGH PRESSURE WILL KEEP THE WATERS BELOW SCEC CRITERIA WITH ONLY A NEARING LOW...REMNANTS OF CHANTAL...TO DISRUPT THAT PATTERN. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 75 91 76 / 50 30 40 20 FMY 89 74 92 75 / 60 30 40 20 GIF 91 73 93 74 / 40 20 50 30 SRQ 89 74 90 76 / 60 40 40 20 BKV 92 72 92 71 / 40 30 50 30 SPG 91 77 90 77 / 60 40 40 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EDT WED JUL 10 2013 .DISCUSSION... SFC/BNDRY LYR WINDS HAVE VEERED TO SE IN THE WAKE OF A HI AMPLITUDE EASTERLY WAVE EXTENDING FROM HAVANA TO JACKSONVILLE. EARLY MORNING SHRA/TSRA ACTIVITY OVER THE GULF STREAM HAS SPUTTERED...MOST PRECIP HAS TRANSITIONED FROM CONVECTIVE TO STRATIFORM IN NATURE. EVEN SO... LATEST RUC ANALYSIS SHOWS AN AREA OF STRONG COUPLET OF MID LVL OMEGA LIFT/UPR LVL DIVERGENCE CO-LOCATED WITH AN AREA OF RESPECTABLE MID LVL VORTICITY ON THE BACKSIDE OF THE WAVE. MORNING SOUNDINGS SHOW DEEP MOISTURE WORKING ITS WAY BACK INTO THE CENTRAL PENINSULA WITH KXMR/KTBW/KMFL PWATS BTWN 1.8"-2.0"...DRY AIR LINGERS TO THE N WITH KJAX PWAT ARND 1.3"...BUT A 2.0" PWAT AT KTLH SUGGESTS THIS DRY AIR SOON WILL BE OVERCOME BY HI MOISTURE POOLING WITHIN A TROF OVER THE DEEP SOUTH. MUCH OF THE PENINSULA IS UNDER AN H100-H85 DEFORMATION ZONE THAT WILL INITIALLY IMPEDE DIURNAL CONVECTION. HOWEVER...SRLY FLOW WILL STRENGTHEN AS THE ERLY WAVE PUSHES INTO THE ERN GOMEX AND IS ABSORBED BY THE TROF OVER THE DEEP SOUTH...ALLOWING ADDITIONAL MOISTURE AS WELL FAVORABLE DYNAMIC LIFT TO PUSH INTO THE PENINSULA. SHOULD SEE THE EAST COAST SEA BREEZE FORM BY MIDDAY WITH ISOLD/SCT CONVECTION DVLPG ALONG THE BOUNDARY...PUSHING TO THE VCNTY OF THE FL TURNPIKE BY LATE AFTN WITH COVERAGE BCMG SCT OVER THE INTERIOR. && .AVIATION... S OF KTIX-KISM...THRU 11/00Z SCT MVFR SHRAS/ISOLD IFR TSRAS...BCMG ISOLD MVFR SHRAS AFT 11/00Z AND CONTG THRU 10-12Z. N OF KTIX-KISM...THRU 10/18Z VFR ALL SITES. BTWN 10/18Z-11/00Z...SCT MVFR SHRAS/ISOLD IFR TSRAS. AFT 11/00Z PREVAILING VFR ALL SITES... ISOLD MVFR SHRAS COASTAL SITES BTWN KMLB-KOMN. && .MARINE... SFC/BNDRY LYR WINDS HAVE VEERED TO SE IN THE WAKE OF A HI AMPLITUDE EASTERLY WAVE EXTENDING FROM HAVANA TO JACKSONVILLE. LATEST DATA BUOY/C-MAN OBS SHOW SFC WINDS AOB 10KTS WITH SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE. SHOULD SEE WINDS INCREASE NEARSHORE BY MIDDAY AS THE EAST COAST SEA BREEZE DVLPS AND PUSHES INLAND. AREAS OF RAIN S OF SEBASTIAN INLET WITH ISOLD SHRAS/TSRAS OVER THE GULF STREAM. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECAST....BRAGAW IMPACT WX...CRISTALDI
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
938 AM EDT WED JUL 10 2013 .UPDATE... THE UPPER LEVEL LOW OVER THE FLORIDA STRAITS THIS MORNING WILL CONTINUE TO MOVE SLOWLY WEST SOUTHWEST TOWARDS THE SOUTHEAST GULF OF MEXICO...AS HIGH PRESSURE SLOWLY WEAKENS OVER THE WESTERN ATLANTIC WATERS. THIS WILL ALLOW FOR A LIGHT SOUTH TO SOUTHEAST STEERING FLOW OVER THE CWA ALONG WITH THE ATMOSPHERE BEING UNSTABLE DUE TO THE COLD AIR ALOFT ASSOCIATED WITH THE UPPER LEVEL LOW. SO WILL CONTINUE THE SCATTERED TO NUMEROUS POPS OVER SOUTH FLORIDA FOR THIS AFTERNOON...AND ADD LOCALLY HEAVY RAINFALL WORDING TO THE ZONES DUE TO THE SLOW STEERING FLOW. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. && .UPDATE...54/BNB .PREV DISCUSSION... /ISSUED 729 AM EDT WED JUL 10 2013/ AVIATION... THE COMBINATION OF A LINGERING LOW LEVEL TROUGH...DEEP TROPICAL MOISTURE AND AN UPPER LEVEL LOW INFLUENCING THE REGION WILL LEAD TO CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS BY LATE MORNING TO EARLY AFTERNOON. THE COVERAGE OF THUNDERSTORMS IS EXPECTED TO BE GREATEST IN THE INTERIOR PORTIONS OF THE PENINSULA. WITH SHOWERS/THUNDERSTORMS...BRIEF PERIODS OF IFR CONDITIONS ARE POSSIBLE. A FEW STRONG THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON. && PREV DISCUSSION... /ISSUED 350 AM EDT WED JUL 10 2013/ .WATCHING DISORGANIZED TROPICAL STORM CHANTAL... DISCUSSION...SATELLITE AND RADAR IMAGERY SHOWS CONVECTION EXTENDING FROM THE ATLANTIC WATERS OFF THE SE FLORIDA COAST EXTENDING ACROSS THE BAHAMAS INTO EASTERN CUBA. THIS IS ASSOCIATED WITH A MID-UPPER LEVEL LOW WHICH WILL TRACK WESTWARD TODAY. A SURFACE TROUGH IS ALIGNED ACROSS SOUTH FL AT THIS TIME AND WILL CONTINUE TO MOVE NW. THIS WILL PLACE SOUTH FL IN A MOIST SOUTHERLY FLOW TODAY-THURSDAY BEHIND THIS TROUGH AXIS. FOR THE NEAR TERM THROUGH EARLY THIS MORNING...EXPECT RAIN TO CONTINUE ALONG MUCH OF THE PALM BEACH COAST EXTENDING INTO NORTHEASTERN BROWARD COUNTY AS WELL. HAVE INCREASED POPS SUBSTANTIALLY ACROSS THESE AREAS FOR EARLY THIS MORNING BASED ON CURRENT ACTIVITY AND TRENDS. FOR TODAY...GFS MOS POPS HAVE DECREASED AND THE LATEST HRRR RUN SHOWS SOME ACTIVITY ALONG THE ATLANTIC COAST BEFORE FOCUSING MOSTLY INLAND IN THE AFTERNOON. HRRR DOES NOT HAVE A GOOD HANDLE ON CURRENT ACTIVITY BUT IT`S TREND SEEMS REASONABLE FOR TODAY, SO WILL FOLLOW THIS TREND, BUT WITH SLIGHTLY HIGHER POPS THAN GFS MOS...MORE IN LINE WITH NAM MOS. LOCALIZED HEAVY RAINFALL IS POSSIBLE TODAY-THURSDAY ALONG WITH THE POTENTIAL OF A FEW THUNDERSTORMS CONTAINING GUSTY WINDS. HOWEVER, INCREASING CLOUDINESS WILL ACT TO LIMIT INSTABILITY, SO MOST OF THE TSTORMS WILL BE ORDINARY. THE FORECAST FOR FRIDAY AND THIS WEEKEND WILL BE HIGHLY DEPENDENT ON THE TRACK AND INTENSITY OF TROPICAL STORM CHANTAL, OR WHAT`S LEFT OF IT. LET`S JUST SAY CHANTAL HAS SEEN BETTER DAYS. AS NHC STATED...REPORTS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT AND SATELLITE IMAGES INDICATE THAT CHANTAL IS LOSING ORGANIZATION. GIVEN THIS TREND AND LAND INTERACTION UPCOMING, CHANTAL WILL HAVE TO HANG ON TOUGH TO BE A SYSTEM NORTH OF THE GREATER ANTILLES. GIVEN THE HIGH UNCERTAINTY INVOLVED, THE FORECAST FOR THE LONGER TERM PERIOD WILL CONTINUE TO REFLECT CLIMO CONDITIONS. IN OTHER WORDS, A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY WITH LITTLE CHANGE IN TEMPS/HUMIDITY LEVELS. SUMMERTIME IN FLORIDA. MARINE...SE WINDS LESS THAN 15 KT WITH LOW SEAS WILL PREVAIL THROUGH THU. THE FORECAST FOR FRIDAY AND THIS WEEKEND IS ALL DEPENDENT ON TS CHANTAL. WINDS/SEAS COULD PICK UP QUITE A BIT OR REMAIN RATHER LOW...IT JUST ALL DEPENDS ON WHAT TRANSPIRES WITH CHANTAL. IT IS LOOKING POORLY ORGANIZED AT THE MOMENT. FIRE WEATHER...NO CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 76 88 78 / 50 30 50 30 FORT LAUDERDALE 88 79 89 79 / 50 30 50 40 MIAMI 89 77 89 78 / 50 30 50 40 NAPLES 89 73 90 75 / 50 30 50 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/DG AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS MIAMI FL
729 AM EDT WED JUL 10 2013 .AVIATION... THE COMBINATION OF A LINGERING LOW LEVEL TROUGH...DEEP TROPICAL MOISTURE AND AN UPPER LEVEL LOW INFLUENCING THE REGION WILL LEAD TO CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS BY LATE MORNING TO EARLY AFTERNOON. THE COVERAGE OF THUNDERSTORMS IS EXPECTED TO BE GREATEST IN THE INTERIOR PORTIONS OF THE PENINSULA. WITH SHOWERS/THUNDERSTORMS...BRIEF PERIODS OF IFR CONDITIONS ARE POSSIBLE. A FEW STRONG THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 350 AM EDT WED JUL 10 2013/ ..WATCHING DISORGANIZED TROPICAL STORM CHANTAL... DISCUSSION...SATELLITE AND RADAR IMAGERY SHOWS CONVECTION EXTENDING FROM THE ATLANTIC WATERS OFF THE SE FLORIDA COAST EXTENDING ACROSS THE BAHAMAS INTO EASTERN CUBA. THIS IS ASSOCIATED WITH A MID-UPPER LEVEL LOW WHICH WILL TRACK WESTWARD TODAY. A SURFACE TROUGH IS ALIGNED ACROSS SOUTH FL AT THIS TIME AND WILL CONTINUE TO MOVE NW. THIS WILL PLACE SOUTH FL IN A MOIST SOUTHERLY FLOW TODAY-THURSDAY BEHIND THIS TROUGH AXIS. FOR THE NEAR TERM THROUGH EARLY THIS MORNING...EXPECT RAIN TO CONTINUE ALONG MUCH OF THE PALM BEACH COAST EXTENDING INTO NORTHEASTERN BROWARD COUNTY AS WELL. HAVE INCREASED POPS SUBSTANTIALLY ACROSS THESE AREAS FOR EARLY THIS MORNING BASED ON CURRENT ACTIVITY AND TRENDS. FOR TODAY...GFS MOS POPS HAVE DECREASED AND THE LATEST HRRR RUN SHOWS SOME ACTIVITY ALONG THE ATLANTIC COAST BEFORE FOCUSING MOSTLY INLAND IN THE AFTERNOON. HRRR DOES NOT HAVE A GOOD HANDLE ON CURRENT ACTIVITY BUT IT`S TREND SEEMS REASONABLE FOR TODAY, SO WILL FOLLOW THIS TREND, BUT WITH SLIGHTLY HIGHER POPS THAN GFS MOS...MORE IN LINE WITH NAM MOS. LOCALIZED HEAVY RAINFALL IS POSSIBLE TODAY-THURSDAY ALONG WITH THE POTENTIAL OF A FEW THUNDERSTORMS CONTAINING GUSTY WINDS. HOWEVER, INCREASING CLOUDINESS WILL ACT TO LIMIT INSTABILITY, SO MOST OF THE TSTORMS WILL BE ORDINARY. THE FORECAST FOR FRIDAY AND THIS WEEKEND WILL BE HIGHLY DEPENDENT ON THE TRACK AND INTENSITY OF TROPICAL STORM CHANTAL, OR WHAT`S LEFT OF IT. LET`S JUST SAY CHANTAL HAS SEEN BETTER DAYS. AS NHC STATED...REPORTS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT AND SATELLITE IMAGES INDICATE THAT CHANTAL IS LOSING ORGANIZATION. GIVEN THIS TREND AND LAND INTERACTION UPCOMING, CHANTAL WILL HAVE TO HANG ON TOUGH TO BE A SYSTEM NORTH OF THE GREATER ANTILLES. GIVEN THE HIGH UNCERTAINTY INVOLVED, THE FORECAST FOR THE LONGER TERM PERIOD WILL CONTINUE TO REFLECT CLIMO CONDITIONS. IN OTHER WORDS, A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY WITH LITTLE CHANGE IN TEMPS/HUMIDITY LEVELS. SUMMERTIME IN FLORIDA. MARINE...SE WINDS LESS THAN 15 KT WITH LOW SEAS WILL PREVAIL THROUGH THU. THE FORECAST FOR FRIDAY AND THIS WEEKEND IS ALL DEPENDENT ON TS CHANTAL. WINDS/SEAS COULD PICK UP QUITE A BIT OR REMAIN RATHER LOW...IT JUST ALL DEPENDS ON WHAT TRANSPIRES WITH CHANTAL. IT IS LOOKING POORLY ORGANIZED AT THE MOMENT. FIRE WEATHER...NO CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 76 88 78 / 50 30 50 30 FORT LAUDERDALE 87 79 89 79 / 50 30 50 40 MIAMI 88 77 89 78 / 50 30 50 40 NAPLES 87 73 90 75 / 50 30 50 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1026 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK SHORT WAVE IN THE CSRA HAS GENERATED MORE SHOWERS AND THUNDERSTORMS IN THAT REGION. SO...INCREASED POPS TO 60 PERCENT IN THE CSRA. OTHERWISE...THE LATEST RAP SHOWS AN H7 SHORTWAVE TROUGH LINGERING OVER THE FORECAST AREA THROUGH 18Z. THE H5 FLOW APPEARS DIFLUENT. THE MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH WILL CONTINUE. EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY NEAR THE TIME OF MAXIMUM HEATING ALTHOUGH THE HRRR INDICATES CONSIDERABLE COVERAGE IN THE WEST PART THIS MORNING. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES WILL SUPPORT VERY HEAVY RAIN IN SOME AREAS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGHER GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE FORECAST AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS THE REST OF TODAY EXCEPT FOR MVFR CIGS IFR VSBYS IN AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS. MVFR CIGS/VSBYS POSSIBLE TONIGHT FROM 08Z-13Z. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
911 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK SHORT WAVE IN THE CSRA HAS GENERATED MORE SHOWERS AND THUNDERSTORMS IN THAT REGION. SO...INCREASED POPS TO 60 PERCENT IN THE CSRA. OTHERWISE...THE LATEST RAP SHOWS AN H7 SHORTWAVE TROUGH LINGERING OVER THE FORECAST AREA THROUGH 18Z. THE H5 FLOW APPEARS DIFLUENT. THE MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH WILL CONTINUE. EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY NEAR THE TIME OF MAXIMUM HEATING ALTHOUGH THE HRRR INDICATES CONSIDERABLE COVERAGE IN THE WEST PART THIS MORNING. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES WILL SUPPORT VERY HEAVY RAIN IN SOME AREAS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGHER GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE FORECAST AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH A 10 TO 15 KT LOW LEVEL JET. MVFR CONDITIONS POSSIBLE ACROSS THE AREA UNTIL 14Z. EXPECT CONDITIONS TO IMPROVE AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN LATER TODAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
644 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /THROUGH TODAY/... THE LATEST RAP SHOWS AN H7 SHORTWAVE TROUGH LINGERING OVER THE FORECAST AREA THROUGH 18Z. THE H5 FLOW APPEARS DIFLUENT. THE MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH WILL CONTINUE. EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY NEAR THE TIME OF MAXIMUM HEATING ALTHOUGH THE HRRR INDICATES CONSIDERABLE COVERAGE IN THE WEST PART THIS MORNING. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES WILL SUPPORT VERY HEAVY RAIN IN SOME AREAS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGHER GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE FORECAST AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH A 10 TO 15 KT LOW LEVEL JET. MVFR CONDITIONS POSSIBLE ACROSS THE AREA UNTIL 14Z. EXPECT CONDITIONS TO IMPROVE AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN LATER TODAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
612 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LATEST RAP SHOWS AN H7 SHORTWAVE TROUGH LINGERING OVER THE FORECAST AREA THROUGH 18Z. THE H5 FLOW APPEARS DIFLUENT. THE MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH WILL CONTINUE. EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY NEAR THE TIME OF MAXIMUM HEATING ALTHOUGH THE HRRR INDICATES CONSIDERABLE COVERAGE IN THE WEST PART THIS MORNING. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES WILL SUPPORT VERY HEAVY RAIN IN SOME AREAS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGH GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH AROUND A 10 TO 15 KT LOW LEVEL JET. MVFR CONDITIONS POSSIBLE ACROSS THE AREA UNTIL 14Z. EXPECT CONDITIONS TO IMPROVE BY AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN LATER TODAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
557 AM EDT WED JUL 10 2013 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST SOUTHERLY FLOW INTO THE FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL MOVE INTO THE REGION AND STALL FRIDAY. && .NEAR TERM /THROUGH TODAY/... THE LATEST RAP SHOWS AN H7 SHORTWAVE TROUGH LINGERING OVER THE FORECAST AREA THROUGH 18Z. THE H5 FLOW APPEARS DIFLUENT. THE MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH WILL CONTINUE. EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY NEAR THE TIME OF MAXIMUM HEATING ALTHOUGH THE HRRR INDICATES CONSIDERABLE COVERAGE IN THE WEST PART THIS MORNING. WE HAVE LEANED TOWARD THE HIGHER GUIDANCE POPS. SLOW STORM MOVEMENT AND PRECIPITABLE WATER AROUND 2 INCHES WILL SUPPORT VERY HEAVY RAIN IN SOME AREAS. CLOUDINESS AND SHOWERS SHOULD HELP HOLD DOWN TEMPERATURES. EXPECT HIGHS MAINLY IN THE UPPER 80S. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA AHEAD OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE NAM AND GFS SHOW THE FRONT NEAR THE AREA THURSDAY NIGHT. CONVERGENCE AHEAD OF THE FRONT AND DEEPENING UPPER-LEVEL TROUGHING SHOULD SUPPORT AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE. A DIFLUENT 1000-500 MB THICKNESS PATTERN AND PRECIPITABLE WATER AROUND 2 INCHES INDICATES SLOW STORM MOVEMENT AND HEAVY RAIN. EXCESSIVE RAIN MAY BECOME AN ISSUE AND FLASH FLOOD WATCHES OR WARNINGS MAY BE NEEDED. LEANED TOWARD THE HIGH GUIDANCE POPS WITH THE GREATER CHANCES NEAR THE TIMES OF MAXIMUM HEATING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE GFS AND ECMWF CONTINUE TO SHOW A MOIST LOW-LEVEL ONSHORE FLOW DURING MUCH OF THE MEDIUM-RANGE PERIOD. THE MODELS INDICATE UPPER TROUGHING OVER THE AREA BECOMING A CUT-OFF LOW AND RETROGRADING SATURDAY AND SUNDAY. ANOTHER CUT-OFF LOW APPEARS TO DEVELOP AND DROP SOUTHWARD TO NEAR THE AREA LATE IN THE PERIOD. THE EXTENT OF MOISTURE ASSOCIATED WITH CHANTAL IS ALSO A COMPLICATION. THE GENERAL PATTERN SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES COOLER THAN CLIMATOLOGY. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... MODEL TIME SECTIONS SHOW PLENTY OF LOW LEVEL MOISTURE WITH AROUND A 10 TO 15 KT LOW LEVEL JET. MVFR CONDITIONS POSSIBLE ACROSS THE AREA UNTIL 14Z. EXPECT CONDITIONS TO IMPROVE BY AROUND 14Z. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN LATER TODAY MAINLY DURING THE AFTERNOON AND EVENING TIME FRAME WITH RESTRICTIONS POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN LATE NIGHT/EARLY MORNING FOG OR STRATUS AS WELL AS SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
906 AM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * NORTHWEST WINDS INCREASING THROUGH MID MORNING WITH GUSTS IN THE UPPER TEENS...BEFORE WINDS SHIFT TO THE NORTHEAST IN THE AFTERNOON WITH LAKE INFLUENCE. MDB //DISCUSSION...UPDATED 12Z... AS THE FRONTAL BOUNDARY IS CURRENTLY SOUTH OF THE TERMINALS THIS MORNING...THE SHOWER/TS DEVELOPMENT ACROSS CENTRAL ILLINOIS WILL REMAIN SOUTH OF THE TERMINALS TODAY. ALTHOUGH WITH FROPA AND A WEAK GRADIENT IN PLACE...SOME SCATTERED LOWER CEILINGS AND FOG REMAIN NEAR THE TERMINALS. WITH THE SUN QUICKLY RISING THIS MORNING...ANY LINGERING FOG/CEILINGS SHOULD QUICKLY DIMINISH WITH LATEST SATELLITE IMAGERY ALREADY SHOWING THIS OCCURRING. ALTHOUGH IT WOULD NOT BE OUT OF THE QUESTION FOR A BRIEF PERIOD OF LOWER CEILINGS AROUND 2KFT OVER THE NEXT HOUR...MAINLY FOR MDW/GYY. ANY FURTHER CLOUD DEVELOPMENT TODAY SHOULD REMAIN SCATTERED AS DRIER AIR CONTINUES TO PUSH SOUTH ON INCREASING NORTHWEST WINDS THIS MORNING. RFD AND DPA SHOULD REMAIN NORTHWEST WITH GUSTS INCREASING BY MID MORNING...WITH ORD/MDW/GYY LIKEWISE OBSERVING THIS TREND BUT ONLY THROUGH THE MORNING. EXPECT A TREND TOWARDS A NORTHEAST DIRECTION BY EARLY AFTERNOON FOR ORD/MDW/GYY...REMAINING THIS DIRECTION UNTIL LATER THIS EVENING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN WIND FORECAST THROUGH EARLY AFTERNOON...MEDIUM CONFIDENCE THAT A SHIFT TO NORTHEAST WILL OCCUR THIS AFTERNOON...MEDIUM CONFIDENCE IN TIMING OF SHIFT. MDB //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. TUESDAY...VFR. RODRIGUEZ && .MARINE... 416 AM CDT AS A TROUGH OF LOW PRESSURE AND ASSOCIATED COLD FRONT BEGIN TO PUSH EAST ACROSS THE NORTHERN PORTIONS OF THE LAKE THIS MORNING...A FAIRLY TIGHT PRESSURE GRADIENT HAS HELPED SOUTHWEST WINDS TO INCREASE TO 15 TO 25 KT OVER THE NORTHERN PORTIONS OF THE LAKE WHILE AREAS FURTHER SOUTH ARE OBSERVING SPEEDS OF 10 TO 20 KT. AS THIS TROUGH/FRONT CONTINUE SOUTHEAST DOWN THE LAKE THIS MORNING...EXPECT THESE SOUTHWEST WINDS TO SHIFT TO THE WEST/NORTHWEST AND THEN HOLD ONTO A NORTHWEST DIRECTION FOR THE REMAINDER OF THE DAY INTO TONIGHT. EXPECT LIGHT NORTHERLY FLOW OVER THE LAKE FOR MOST OF THURSDAY AS HIGH PRESSURE SLOWLY SHIFTS EAST TOWARDS THE CENTRAL GREAT LAKES. BY FRIDAY WINDS TURN BACK TO A SOUTHERLY DIRECTION...AS THIS HIGH SETTLES OVER THE EASTERN GREAT LAKES INTO THE WEEKEND. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
654 AM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * LINGERING FOG AND SCATTERED LOW CEILINGS DIMINISHING EARLY THIS MORNING. * NORTHWEST WINDS INCREASING THROUGH MID MORNING WITH GUSTS IN THE UPPER TEENS...BEFORE WINDS SHIFT TO THE NORTHEAST IN THE AFTERNOON WITH LAKE INFLUENCE. RODRIGUEZ //DISCUSSION...UPDATED 12Z... AS THE FRONTAL BOUNDARY IS CURRENTLY SOUTH OF THE TERMINALS THIS MORNING...THE SHOWER/TS DEVELOPMENT ACROSS CENTRAL ILLINOIS WILL REMAIN SOUTH OF THE TERMINALS TODAY. ALTHOUGH WITH FROPA AND A WEAK GRADIENT IN PLACE...SOME SCATTERED LOWER CEILINGS AND FOG REMAIN NEAR THE TERMINALS. WITH THE SUN QUICKLY RISING THIS MORNING...ANY LINGERING FOG/CEILINGS SHOULD QUICKLY DIMINISH WITH LATEST SATELLITE IMAGERY ALREADY SHOWING THIS OCCURRING. ALTHOUGH IT WOULD NOT BE OUT OF THE QUESTION FOR A BRIEF PERIOD OF LOWER CEILINGS AROUND 2KFT OVER THE NEXT HOUR...MAINLY FOR MDW/GYY. ANY FURTHER CLOUD DEVELOPMENT TODAY SHOULD REMAIN SCATTERED AS DRIER AIR CONTINUES TO PUSH SOUTH ON INCREASING NORTHWEST WINDS THIS MORNING. RFD AND DPA SHOULD REMAIN NORTHWEST WITH GUSTS INCREASING BY MID MORNING...WITH ORD/MDW/GYY LIKEWISE OBSERVING THIS TREND BUT ONLY THROUGH THE MORNING. EXPECT A TREND TOWARDS A NORTHEAST DIRECTION BY EARLY AFTERNOON FOR ORD/MDW/GYY...REMAINING THIS DIRECTION UNTIL LATER THIS EVENING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 12Z... * MEDIUM HIGH CONFIDENCE WITH FOG/CEILING TRENDS. * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. TUESDAY...VFR. RODRIGUEZ && .MARINE... 416 AM CDT AS A TROUGH OF LOW PRESSURE AND ASSOCIATED COLD FRONT BEGIN TO PUSH EAST ACROSS THE NORTHERN PORTIONS OF THE LAKE THIS MORNING...A FAIRLY TIGHT PRESSURE GRADIENT HAS HELPED SOUTHWEST WINDS TO INCREASE TO 15 TO 25 KT OVER THE NORTHERN PORTIONS OF THE LAKE WHILE AREAS FURTHER SOUTH ARE OBSERVING SPEEDS OF 10 TO 20 KT. AS THIS TROUGH/FRONT CONTINUE SOUTHEAST DOWN THE LAKE THIS MORNING...EXPECT THESE SOUTHWEST WINDS TO SHIFT TO THE WEST/NORTHWEST AND THEN HOLD ONTO A NORTHWEST DIRECTION FOR THE REMAINDER OF THE DAY INTO TONIGHT. EXPECT LIGHT NORTHERLY FLOW OVER THE LAKE FOR MOST OF THURSDAY AS HIGH PRESSURE SLOWLY SHIFTS EAST TOWARDS THE CENTRAL GREAT LAKES. BY FRIDAY WINDS TURN BACK TO A SOUTHERLY DIRECTION...AS THIS HIGH SETTLES OVER THE EASTERN GREAT LAKES INTO THE WEEKEND. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
601 AM CDT WED JUL 10 2013 ...UPDATE TO AVIATION FOR 12 COORDINATED UNIVERSAL TIME TAFS... .SYNOPSIS... ISSUED AT 314 AM CDT WED JUL 10 2013 A FAIRLY INTENSE SHORTWAVE TROUGH MOVED ACROSS THE NORTHERN PLAINS INTO THE UPPER MIDWEST REGION TUESDAY EVENING. THERE WAS A 70-80 KNOT 250MB JET STREAK ASSOCIATED WITH THIS STORM SYSTEM CENTERED ACROSS EASTERN SOUTH DAKOTA PER 10.00Z RAOB AND RAP ANALYSIS. THE COLD FRONT TIED TO THIS STORM SYSTEM PUSHED INTO NORTHERN KANSAS AND BY 08Z EXTENDED FROM EAST CENTRAL COLORADO TO NORTH CENTRAL KANSAS. THE THUNDERSTORM ACTIVITY THAT MOVED ACROSS PORTIONS OF SOUTHWEST AND SOUTH CENTRAL KANSAS YESTERDAY EVENING CONTINUED TO MOVE SLOWLY SOUTHEAST INTO NORTHERN OKLAHOMA. ANOTHER SMALL CLUSTER OF STRONG THUNDERSTORMS DEVELOPED ACROSS FAR NORTHWEST KANSAS ADJACENT THE SOUTHWEST NEBRASKA BORDER...WHICH WAS ALSO MOVING SOUTHEAST TOWARD THE INTERSTATE 70 CORRIDOR. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT WED JUL 10 2013 THE FORECAST FOR TODAY AND TONIGHT WILL BE CHALLENGING WITH REGARDS TO PLACEMENT, TIMING, AND INTENSITY OF THUNDERSTORMS. THE COLD FRONT WILL STALL OUT AND DISSOLVE AS IT APPROACHES THE OKLAHOMA BORDER TODAY. WINDS NORTH OF THE FRONT WILL BECOME EAST AND EVENTUALLY SOUTHEAST...ESPECIALLY ALONG THE COLORADO BORDER. A RICH SOURCE OF LOW LEVEL MOISTURE WILL BE IN PLACE NORTH OF THE FRONT WITH SURFACE DEWPOINTS IN THE MID TO UPPER 60S ACROSS PORTIONS OF CENTRAL AND WESTERN KANSAS. DESPITE THE PASSAGE OF THE COLD FRONT AND BEING ON THE NORTH SIDE OF THE BOUNDARY...AFTERNOON TEMPERATURES WILL STILL REACH THE 95 TO 98F RANGE ACROSS MUCH OF THE SOUTHWEST KANSAS REGION WITH STILL FAIRLY HIGH LOW LEVEL THICKNESSES. LOWER TROPOSPHERIC CONVERGENCE ALONG THE OLD FRONTAL ZONE ACROSS FAR SOUTHWEST KANSAS NEAR THE OKLAHOMA BORDER WILL AID IN FORMATION OF AFTERNOON THUNDERSTORMS. THERE WILL BE A GREATER AMOUNT OF SBCAPE TODAY WITH MUCH HIGHER DEWPOINT VALUES/MOISTURE CONTENT OVER YESTERDAY. THIS WOULD ARGUE FOR MORE ORGANIZED CONVECTION. ONE OR MORE MESOSCALE CONVECTIVE SYSTEMS (MCS) MAY DEVELOP FROM SOUTHWEST KANSAS NORTH-NORTHWESTWARD TO THE CHEYENNE RIDGE AREA. THE GREATER RISK FOR SEVERE STORMS WILL BE FARTHER NORTH (MOSTLY NORTH OF THE DDC FORECAST AREA) WHERE DEEP LAYER SHEAR WILL SUPPORT MORE ORGANIZED MULTI-CELL CLUSTERS AND PERHAPS A SUPERCELL OR TWO. WILL KEEP POPS IN THE 30 TO 40 PERCENT TERRITORY GIVEN THE UNCERTAINTY OF PLACEMENT AND COVERAGE OF THUNDERSTORM CLUSTERS/EVENTUAL MCS...HOWEVER POPS MAY NEED TO BE INCREASED FOR SOME SECTIONS OF THE FORECAST AREA AS SHORT TERM HIGHER RESOLUTION MODELS LIKE THE HRRR GET A BETTER HANDLE ON THE ENVIRONMENT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 400 AM CDT WED JUL 10 2013 THE EXTENDED PERIOD IS DRY AND HOT. ON THURSDAY, LEE TROUGHING AND WARM AIR ADVECTION ALONG WITH 850 HPA TEMPS IN THE 20S DEG C WILL SUPPORT MAXIMUMS IN THE MID TO UPPER 90S DEG F. NO PRECIPITATION IS EXPECTED. ON FRIDAY, THE 850 HPA WARM PLUME WILL SPREAD FARTHER NORTH AND EAST WITH 850 HPA TEMPERATURES FLIRTING WITH 30 DEG C. THIS SUPPORTS MIX DOWN TEMPERATURES IN THE LOW 100S DEG F FRIDAY AND SATURDAY. MINIMUMS WILL BE IN THE 70S DEG F THROUGH THIS PERIOD. ON SUNDAY, A JET STREAK MOVING ACROSS THE NORTHERN PLAINS INTO THE CENTRAL CANADIAN PRAIRIE PROVINCES WILL USHER IN THE PASSAGE OF A COLD FRONT ACROSS NEBRASKA AND WILL STALL OUT ACROSS THE CORNHUSKER STATE. THIS COULD KNOCK DOWN TEMPERATURES LOCALLY A FEW DEGREES. BOTH THE GFS AND ECMWF SHOW CONVECTION ASSOCIATED WITH THE FRONT AND ANY POST FRONTAL/OROGRAPHIC CONVECTION REMAINING WELL WEST/NORTHWEST OF THE AREA. AS RESULT, WENT WITH AOB 14 PERCENT PRECIPITATION PROBABILITY PERCENTAGE POINTS. THEREAFTER, THE RIDGE WILL CONTINUE TO DOMINATE WITH DRY AND HOT CONDITIONS PREVAILING. THERE COULD BE RETROGRESSION OF A SUBTROPICAL LOW NEXT WEEK, BUT THIS WILL NOT HAVE ANY SIGNIFICANT IMPACTS TO SW KANSAS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 600 AM CDT WED JUL 10 2013 SHOWERS AND THUNDERSTORMS WILL BE LIKELY AGAIN THIS AFTERNOON AND EVENING. CLOUDS BASES EXPECTED TO BE FAIRLY HIGH, SO VFR CIGS SHOULD PREVAIL. WINDS WILL BE UPSLOPE/EASTERLY 10-20 KT. && .PRELIMINARY POINT TEMPS/POPS... DDC 96 70 97 73 / 30 40 10 0 GCK 94 69 98 73 / 30 40 0 0 EHA 95 69 98 72 / 30 30 0 10 LBL 97 70 99 72 / 30 30 0 0 HYS 93 69 95 73 / 20 30 20 0 P28 99 72 98 73 / 20 30 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...SUGDEN AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
947 AM EDT WED JUL 10 2013 .FORECAST UPDATE... Issued at 945 AM EDT Wed Jul 10 2013 Local WRF and to some extent the HRRR pick up well on current spread of convection out to our west and north this morning. Bumped up pops a little over my southwest zones, where some scattered storms have popped up this morning. Cloud cover is coming in ahead of the central Illinois convection as well as with the cells to our west. These clouds should help to temper our highs some today, but dewpoints are fairly highs, so heat indices likely still will top out in the mid/upper 90s, perhaps even 100 in the SDF metro. Storms firing off to our west indicate somewhat of an uncapped atmosphere, but AMDAR sounding out of SDF has a weak cap at 800 mb, possibly from sinking air with the cirrus shield our ahead of those storms in central Illinois. As of this writing, that subsidence looks like it is weakening the cells just west of Hancock and Ohio counties. Think this cap will be long enough to allow what the local WRF shows as a line of storms moving in from the north later this afternoon. By then soundings indicate plenty of CAPE despite the cloud cover, so these storms will have enough instability to stay together and producing damaging winds and possibly some hail. We`ll have to get fairly tall storms to get the hail to survive down to the surface, given a very moist airmass in place. && .SHORT TERM (Now through Thursday)... Issued at 316 AM EDT Wed Jul 10 2013 ...Strong to Severe Storms Likely This Afternoon Along With Locally Heavy Rainfall... In the near term, passing mid-level wave now in Ohio will continue to track eastward early this morning. Bulk of the convection associated with the wave will pass northeast of our area, but some isolated-scattered showers will be possible mainly across our eastern half this morning. Clouds are rapidly clearing out to the west, so we should see some partial clearing by sunrise in the central and western sections. Temperatures will remain for the remainder of the night with readings bottoming out in the lower-middle 70s in most locations with upper 70s being more likely down in the urban centers. Next mid-level wave within the mean flow will approach the region later this morning and into the afternoon hours. Expect convection to develop over the next few hours from MO into IL with much of region remaining fairly dry. In fact, it appears that we`ll likely see some partly to mostly sunny skies this morning which will allow solar insolation to really get temperatures warmed up. By mid-late morning, convection to our northwest will begin to push eastward. As the mid-level wave and associated surface boundary approach, we expect convection to become more widespread during the afternoon and into the evening hours. Regarding convective potential and intensity, much of our region will reside on the southern edge of the westerlies this afternoon. This places much of the better shear to our north. However, with the expected insolation this morning, we should see temperatures warm into the upper 80s and perhaps lower 90s in some spots. This combined with dewpoints in the lower-mid 70s will result in strong instability developing as cooler mid-level temperatures overspread the region. Convection will probably be multi-modal with lines and segments being likely. Given the decreasing shear profile from NE to SW across our region, it appears that damaging winds/microbursts and large hail will be the primary severe weather threats across our region. With the wet ground in many places in central KY, sub-severe winds could easily result in trees coming down fairly easily. In addition to the severe weather threat, precipitable water values are still forecast to run quite high this afternoon with readings in the 1.9-2.0 inch range. This will result in locally heavy rainfall with any of the storms that develop. Given the rainfall over the past weekend, we are still dealing with fairly wet grounds. Thus, the torrential rainfall with this afternoon`s storms will have the capability of producing flash flooding. The storms look to have some movement to them, so the flooding threat could be more attributed to training of cells as well. Showers and thunderstorms are expected to continue into the evening hours, but should diminish with the loss of daytime heating this evening. We should see a diminishing trend of PoPs from NW to SE through the overnight hours with much of southern Indiana and western/NC KY going dry by Thursday morning. Overnight lows will cool into the 60s. A few scattered storms will be possible across the east/southeast Thursday morning and into the early afternoon hours, but most locations should see dry conditions by Thursday evening. Highs Thursday will be cooler than Wednesday with readings in the lower 80s. .LONG TERM (Thursday Night through Tuesday)... Issued at 302 AM EDT Wed Jul 10 2013 Drier and cooler air will be working its way into the area Thursday night in the wake of the cold front. At the surface high pressure will build in across the Ohio Valley through Friday. A trough aloft will keep the region in northwesterly flow through Friday, before a ridge builds across the Great Lakes region. Dry conditions look to prevail through the weekend, though diurnal storms will begin creeping back towards the far southeastern portions of the forecast area by Sunday afternoon. Temperatures will be coolest at the beginning of the period. Lows on Friday morning will be in the low to mid 60s with highs in the low to mid 80s. By Sunday lows will be in the upper 60s with highs in the upper 80s. Moisture return will continue through the beginning of the next work week. Isolated to scattered afternoon thunderstorms will be possible Monday and Tuesday afternoons, especially across south central Kentucky. Temperatures will continue the slow warming trend with highs in the upper 80s to lower 90s by Tuesday and lows in the lower 70s. && .AVIATION (12Z TAF Update)... Issued at 644 AM EDT Wed Jul 10 2013 VFR conditions are expected for early portion of the TAF period. Mid-level clouds associated with departing mid-level wave are moving out and have cleared out of the terminals. So for the next few hours, we`ll see mostly clear skies but should see a cu field develop toward late morning. Surface cold front and next mid-level wave are currently out to our west and are heading eastward. These features will impact the region this afternoon during peak heating. This should result in convective development across the region. Still a little uncertain with regards to overall convective evolution, so plan on going with VCTS at the terminals after 10/18Z. Convection will likely linger into the evening/overnight hours before diminishing. Outside of storms, VFR conditions will prevail, but if a storm impacts the terminal, a drop to IFR conditions due to heavy rain is likely. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........RJS Short Term.......MJ Long Term........EER Aviation.........MJ
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1001 AM EDT WED JUL 10 2013 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL DRIFT EAST ACROSS THE NORTHEASTERN STATES. HIGH PRESSURE WILL PERSIST OFFSHORE. A COLD FRONT IS EXPECTED TO PASS THROUGH THE AREA THURSDAY BEFORE STALLING JUST TO THE SOUTH THIS WEEKEND. AN UPPPER LEVEL AREA OF LOW PRESSURE MAY TRACK INTO THE REGION DURING THE FIRST PART OF THE NEW WEEK. && .NEAR TERM /THROUGH TONIGHT/... A SHORTWAVE TROUGH AHEAD OF THE MAIN UPPER LEVEL TROUGH ARE WELL DEFINED ON WV IMAGERY THIS MORNING. CLOUD COVER AND LIGHT SHOWERS HAVE INCREASED OVER THE CWA. SHOWERS ARE LIGHT BUT HIGH DEWPTS AND PWAT VALUES NEAR 2 INCHES WILL OFFER A QUICK MODERATE SHOWER FOR THE NEXT FEW HOURS. THIS AFTERNOON... SHORTWAVE NEARS THE CWA AND THUNDERSTORMS WILL BE POSSIBLE. SW FLOW WILL MAINTAIN THE SFC TROUGH ACROSS THE PIEDMONT REGION. 12Z MODIFIED IAD RAOB PROVES SATURATED COLUMN. HIGH TEMPS ARE EXPECTED TO REACH THE UPPER 80S AND SFC BASED INSTABILITY IS EXPECTED TO REACH AROUND 2000 J/KG. LITTLE SHEAR AND CLOUD COVER WILL PLAY A LARGE ROLE IN DAMPENING THE EFFECTS OF A SVR THREAT THIS AFTERNOON AND EVENING. ISO-SCT THUNDERSTORMS ARE POSSIBLE AFTER 12 PM TODAY WITH THE MAIN THREAT FOR FLASH FLOODING. 1-HR FFG IS LOWER IN WASH DC AND BALT AND WESTERN SUBURBS. ISO THREAT FOR WET MICROBURSTS LATE THIS AFTERNOON WITH DCAPE VALUES NEAR 500 J/KG. STRONG THUNDERSTORMS WILL INCREASE IN COVERAGE ACROSS THE OHIO VALLEY TODAY. THESE THUNDERSTORMS WILL MOVE INTO THE MID ATLANTIC THIS EVENING. 11Z HRRR HAS SHOWERS AND THUNDERSTORMS MOVING INTO THE MTNS AROUND 00Z. ACTIVITY IS EXPECTED TO WANE AS IT MOVES OVER THE MTNS BUT SHOWERS AND ELEVATED THUNDERSTORMS MAY BE POSSIBLE OVERNIGHT. && .SHORT TERM / THURSDAY THROUGH 6 AM THURSDAY/... INSTABILITY REMAINS THROUGH THE NIGHT AS THE TROUGH SHIFT EAST INTO THE MID-ATLANTIC. IN FACT...CHANCE POPS WERE INTRODUCED FOR MOST OF THE AREA LATE TONIGHT AS ELEVATED INSTABILITY INCREASES OVERNIGHT. MIN TEMPS UP TO 10 DEGREES ABOVE NORMAL WITH CLOUDS AND MOISTURE...GENERALLY LOW TO MID 70S PER MAV/MET/SREF BLEND. && .LONG TERM /THURSDAY THROUGH TUESDAY/... SVRL DAYS AGO I HV TO ADMIT I HAD MY DOUBTS WHEN THE XTND MDLS WERE PROJECTING A CD FNT TO PUSH THRU THE MID ATLC ON THU AND PUSH ALL THE WAY TO GA. THIS IS NOT NRML MID JUL FARE...BUT IT INDEED APPEARS THAT THE MDLS HAD A GOOD HANDLE ON WHAT IS XPCTD TO HAPPEN. AND W/ THAT FNT MOVG THRU THE AREA THU AFTN THERE`LL BE CHC FOR PCPN/TSTMS. BOTH NAM/GFS ARE GIVING LKLY POPS. WE`VE DONE STUDIES ON MDL POP VS. WHAT REALLY OCCURRED...AND IN THE SUMMER MONTHS WHEN IN THE 60-70 PCNT RANGE MDLS TEND TO OVRFCST...WHICH MAKES SENSE GIVEN THE NRMLY HIT OR MISS NAUTRE OF SUMMER STORMS. IN SOME SEASONS 60-70 REALLY END UP AS CATEGORICAL BUT NOT SUMMER...SO WE`LL STAY W/ THE CURRENT 60 POP FOR THU. TEMP WISE LATELY WE`VE BEEN FCSTG A FEW DEGS TOO WARM...AND GIVEN THE CLD CVR/CHCS OF PCPN WL HOLD HIGH TEMPS IN THE LM80S...XCPT MU80S IN THE CITIES. TROF TO MOVE OFF THE CST FRI..BRINGING SOME CLRG TO THE RGN. HIGH TEMPS AGN IN M80S. I DID A QUICK STUDY LAST WK ABT SUMMER TEMPS IN THE 2000S...AND AGN TNGT SHOWS THAT FOR AVG TEMPS IN THE 2000S THIS YR IS IN THE MIDDLE OF THE PACK - #6 AT BOTH DCA AND BWI...AND THERE IS NOTHING NOTABLE IN THE XTND TO IMPLY THAT THE RANKING IS GOING TO CLIMB IN THE COMING DAYS. ERLR THERE WAS A DEGREE OF DISAGREEMENT IN THE MDLS - U.S. MDLS SHOWED A CUT OFF LOW FORMING OVR NEW ENGLAND THIS WKND WHILE 12Z ECM SHOWED THE TROF AS BEING PROGRESSIVE AND MOVING INTO ALTC....LVG HIGH PRES OVR THE MID ALTC. BUT AS I`M WRITING THE NEW ECM IS COMING IN...AND ALSO SHOWING THE LOW OVR NEW ENGLAND SUN AND THEN SLOWLY TRACKING S IN THE NEW WK. QUSTN WL BE WHETHER THIS WL BE STRONG ENUF TO GENERATE ANY PCPN - THIS IS NOT A NRML MID JUL PATTERN. FOR NOW WL STAY W/ CHC POPS FOR SUN-MON. WE ARE CLIMATOLOGICALLY IN THE WARMEST PD OF THE YR...W/ HIGHS IN THE U80S. THIS PATTERN DOES NOT MAKE ME WANT TO FCST TEMPS ANY WARMER THAN THAT. WE`VE RCVD CALLS ABT CHANTAL. AT THIS MOMENT ON STLT IT LOOKS XTRMLY DISORGANIZED. AND W/ CD FNT MOVING S OF US IT APPEARS THAT IT`LL BE DIFFICULT FOR REMNANTS TO GET THIS FAR N. REGARDLESS ANY EFFECTS FM THIS STORM..IF THERE ARE ANY...ARE MANY DAYS AWAY FM AFFECTING THE MID ALTC. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... MVFR/IFR CONDITIONS POSSIBLE IN HEAVY RAIN AND THUNDERSTORMS TODAY. ACTIVE WEATHER PATTERN RESTARTS FOR THE REGION TODAY AS A TROUGH APPROACHES FROM THE WEST...THUNDERSTORMS LIKELY TODAY..IFR CONDS IN HEAVIEST ACTIVITY. SWLY AROUND 10 KT WITH GUSTS TO 20 KT INTO THIS EVENING. MAJORITY OF XTND PD IS XPCTD TO FEATURE VFR CONDS. && .MARINE... LOWER SRN MD PORTION OF THE BAY IN SCA THROUGH MIDDAY. THIS IS CURRENTLY VERIFYING...MAY NEED TO BE EXPANDED NORTH BY THE LATE MORNING. ALL WATERS IN SCA FOR THE AFTERNOON/EVENING...THEN MAIN PORTIONS OF THE BAY OVERNIGHT. THUNDERSTORMS THIS AFTERNOON MAY REQUIRE SOME SPECIAL MARINE WARNINGS FOR WIND GUSTS IN EXCESS OF 34 KT. GUSTS TO NEAR 20 KT MAY BE PSBL ON THE LWR BAY/TIDAL PTMC E OF COBB ISLAND THU. PRES GRAD WL BE LGT MAJORITY OF XTND...AS OF NOW NO SCA XPCTD FOR THE WKND. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 4 AM EDT THURSDAY FOR ANZ530>532-537>541. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO MIDNIGHT EDT TONIGHT FOR ANZ535-536-542. SMALL CRAFT ADVISORY UNTIL 4 AM EDT THURSDAY FOR ANZ533-534- 543. SMALL CRAFT ADVISORY FROM 8 AM TO 2 PM EDT THURSDAY FOR ANZ534- 537-543. && $$ UPDATE...HAS PREVIOUS...BAJ/ADW
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1030 AM CDT WED JUL 10 2013 .UPDATE... ISSUED AT 1030 AM CDT WED JUL 10 2013 MAIN CONCERNS ARE PRECIPITATION CHANCES THIS AFTERNOON AND WIND SPEEDS AND RESULTING WAVE HEIGHTS ALONG THE SOUTH SHORE OF LAKE SUPERIOR. CANADIAN RADARS SHOWING AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS SOUTHERN MANITOBA IN RESPONSE TO A WELL- DEFINED SHORT WAVE VISIBLE IN THE LATEST WATER VAPOR LOOP. NO MODELS ARE CAPTURING THIS FEATURE...BUT BASED ON LATEST TRENDS... WILL ADD SOME CHANCE POPS ALONG THE CANADIAN BORDER THIS AFTERNOON. WITH NORTHWEST SURFACE FLOW...WILL NEED TO WATCH WIND SPEEDS ALONG THE SOUTH SHORE OF LAKE SUPERIOR...ESPECIALLY ACROSS THE APOSTLE ISLANDS. MODEL SOUNDINGS SHOW A DEEP AFTERNOON BOUNDARY LAYER WITH UP TO 30 KTS TO MIX TO THE SURFACE...BUT SURFACE BASED GUIDANCE SHOWS WIND SPEEDS MAXING OUT AROUND 15 KTS BY MID-AFTERNOON. WILL HOLD OFF ON ISSUANCE OF A SMALL CRAFT ADVISORY...BUT MAY NEED TO RE-EVALUATE THIS AFTERNOON. ADJUSTED SKY GRIDS TO ACCOUNT FOR ROBUST CU FIELD ACROSS THE MN ARROWHEAD. REST OF THE FORECAST IS IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. && .SHORT TERM.../NOW - TONIGHT/ AT 300AM/0800Z...THERE WAS A MID/UPPER LEVEL TROUGH CENTERED FROM WESTERN ONTARIO TO THE EASTERN FORECAST AREA. SURFACE HIGH PRESSURE WAS CENTERED IN THE WESTERN DAKOTAS. MUCH OF THE NORTHLAND HAD CLEAR SKIES...EXCEPT FOR PARTS OF THE EASTERN AND NORTHERN FORECAST AREA. MORE EXTENSIVE CLOUD COVER WAS LOCATED FARTHER NORTH AND EAST OF THE NORTHLAND...WHILE MUCH OF THE NORTHERN PLAINS HAD CLEAR SKIES. MUCH OF THE NORTHLAND HAD 5 TO 10 MPH WNW TO NW WINDS...WHICH WAS HELPING TO KEEP THE TEMPERATURES UP. THE TEMPERATURES RANGED FROM THE MID 50S TO MID 60S. TODAY...THE SURFACE HIGH PRESSURE IN THE NORTHERN PLAINS WILL BEGIN TO SHIFT EAST INTO THE UPPER MIDWEST. THE NORTHLAND CAN EXPECT RELATIVELY SUNNY AND WEATHER EARLY THIS MORNING. HOWEVER...SCATTERED CUMULUS WILL LIKELY DEVELOP BY THE AFTERNOON SINCE THE MODEL SOUNDINGS INDICATE RELATIVELY LOW CONVECTIVE TEMPERATURES IN THE BREEZY NW FLOW. THE LATEST HRRR RUNS ARE PICKING UP ON THE SCATTERED CUMULUS. ALSO...THE NAM12 AND GFS ARE SHOWING A SHORTWAVE MOVING INTO THE WESTERN FORECAST AREA THIS AFTERNOON...AND THE NAM12/DLHWRF/WRF MODELS ARE HINTING AT A LOW THREAT OF SHOWERS AND STORMS WITH THIS SHORTWAVE. I ADDED ISOLATED STORMS ACROSS THE WESTERN FORECAST AREA FOR THIS AFTERNOON AND EARLY EVENING. HIGH TEMPERATURES SHOULD BE IN THE MID 70S TO NEAR 80 DEGREES. TONIGHT...THE RELATIVELY DRY CONDITIONS THAT WILL DEVELOP THIS AFTERNOON DUE TO THE MIXING IN THE NW FLOW...COMBINED WITH THE WEAKENING WINDS TONIGHT AS HIGH PRESSURE MOVES INTO THE UPPER MIDWEST...WILL HELP FOR DECENT RADIATIONAL COOLING TONIGHT. I LOWERED THE LOW TEMPERATURE FORECAST BY A COUPLE TO FEW DEGREES. THE LOW TEMPERATURES SHOULD AROUND 50 DEGREES TO THE MID 50S...BUT I COULD SEE ISOLATED AREAS GETTING DOWN TO THE MID 40S DEPENDING ON AFTERNOON DEW POINT TEMPERATURES. DESPITE THE CLEAR SKIES AND NEGLIGIBLE WINDS THAT WILL DEVELOP...I THINK THE THREAT OF FOG IS LOW BECAUSE OF THE RELATIVELY DRY CONDITIONS THAT WILL DEVELOP IN THE AFTERNOON. IF THERE IS ANY FOG...IT WILL PROBABLY DEVELOP VERY LATE IN THE NIGHT AND BE ISOLATED. .LONG TERM.../THURSDAY - TUESDAY/ FOCUS IN EXTENDED ON RETURN OF UPPER LEVEL RIDGE AND SRLY FLOW WITH INCREASING H85 TEMPS THURSDAY NIGHT/FRIDAY...THEN STALLED BAROCLINIC ZONE THAT WILL BECOME FOCUS FOR RAIN/TSTORMS THROUGH THE WEEKEND. LONG RANGE MODELS CONTINUE TO STRUGGLE WITH THE PLACEMENT OF THE STALLED FRONT AND ASSOCIATED BAND OF PRECIPITATION. HAVE POPS MOVING INTO NW ZONES FRIDAY NIGHT...WITH WIDESPREAD HIGH CHANCE/LIKELY POPS FOR SHOWERS AND TSTORMS ACROSS THE CWA SATURDAY/SUNDAY. LATEST NAM DEPICTS VERY HIGH PWATS APPROACHING 2 INCHES SPREADS OVER THE NORTHLAND THROUGH FRIDAY EVENING. IF THE BOUNDARY DOES STALL OVER A PORTION OF THE FORECAST AREA...THE ABUNDANT MOISTURE AND PROLONGED PERIOD OF RAIN COULD LEAD TO LOCALIZED FLOODING CONCERNS. THE MAIN THREAT FOR HEAVY RAIN AT THIS TIME LOOKS TO BE FRIDAY NIGHT THROUGH SATURDAY NIGHT. && .AVIATION.../06Z TAF ISSUANCE/ VFR CONDITIONS HAVE RETURNED TO THE TERMINALS THIS EVENING AFTER A COLD FRONT MOVED THROUGH THE AREA. DRIER AIR FILTERING INTO THE AREA FROM THE NORTHWEST IS EXPECTED TO KEEP FOG FROM FORMING AT MOST TERMINALS...BUT KHYR MAY STILL FORM SOME...DUE TO THE LATER TIMING OF THE DRIER AIR. IN THE 14Z- 16Z TIME RANGE WEDNESDAY NORTHWEST WINDS ARE EXPECTED TO INCREASE TO 10-15KTS AND GUST TO 20KTS MOST LOCATIONS...BUT LIGHTER AT KHYR. WINDS TO DIMINISH AGAIN AFTER 23Z. VFR CONDITIONS EXPECTED 14Z THROUGH END OF TAF PERIOD. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LSZ140-141. && $$ UPDATE...ROGERS SHORT TERM...GROCHOCINSKI LONG TERM....GRANING AVIATION...GRANING
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
721 AM CDT WED JUL 10 2013 .UPDATE... ISSUED AT 633 AM CDT WED JUL 10 2013 UPDATED GRIDS AND PRODUCTS TO RAISE POPS OVER AREAS WHERE CONVECTION HAS BLOSSOMED THIS MORNING. KANOFSKY && .SHORT TERM...(THROUGH LATE THIS AFTERNOON) ISSUED AT 311 AM CDT WED JUL 10 2013 CONVECTION TRENDS OVERNIGHT HAVE BEEN A BIT INCOHERENT TO SAY THE LEAST...BUT REGIONAL RADAR IMAGERY OVER THE LAST 90 MINUTES SEEM TO SUGGEST THAT VEERING LOW LEVEL JET AND ASSOCIATED WARM ADVECTION FROM W MO INTO S IL WILL BE THE MAIN DRIVING MECHANISM FOR THUNDERSTORMS EARLY TODAY. OVER THE LAST 30 MINUTES THERE HAS BEEN A RAPID INCREASE IN COVERAGE OVER N OZARKS...AND IT APPEARS THIS IS TRYING TO "CONNECT" WITH SPOTTIER STORMS THAT DEVELOPED NW OF STL SHORTLY AFTER 06Z. THIS ENTIRE AREA SHOULD SHIFT SOUTH WITH THE VEERING LOW LEVEL JET AS THE MORNING PROGRESSES. MEANWHILE... LINGERING CONVECTION OVER NW MO/SE NE CERTAINLY INDICATES THAT SOME THUNDERSTORM THREAT WILL ALSO CONTINUE NEAR THE APPROACHING COLD FRONT AT LEAST FOR A FEW HOURS THIS MORNING. THE EXACT EVOLUTION OF THE PRECIPITATION THIS MORNING WILL HAVE A MAJOR IMPACT ON TIMING AND LOCATION OF ADDITIONAL THUNDERSTORM ACTIVITY AND SEVERE WEATHER POTENTIAL THIS AFTERNOON....BUT FOR NOW HAVE MAINTAINED HIGH CHANCE POPS FOR AREAS SE OF STL. AM A BIT CONCERNED THAT THIS MORNINGS ACTIVITY MAY SET UP THE PRIMARY FOCUS FOR ADDITIONAL CONVECTION OVER FAR S SECTIONS OF OUR CWA...AND IN ADDITION STRONG W COMPONENT TO SURFACE/LOW LEVEL FLOW S OF THE COLD FRONT SHOULD CERTAINLY LIMIT CONVERGENCE ALONG THE ACTUAL FRONTAL BOUNDARY. HOWEVER...AMS WILL CERTAINLY REMAIN QUITE UNSTABLE WITH MUCAPES OF 3000-4000 J/KG...AND ALL SYNOPTIC MODELS ARE SUGGESTING NW FLOW WILL ALLOW SUBTLE SHORTWAVE ENERGY TO PROPAGATE INTO THE AREA...SO WILL NOT TOTALLY GIVE UP PRECIP CHANCES ALONG THE ACTUAL COLD FRONT EVEN IF MORE SIGNIFICANT BOUNDARY ENDS UP WELL SOUTH. NO MAJOR CHANGES TO GOING TEMPS...MU80S IN OUR NW COUNTIES TO THE LM90S IN OUR SE...WHERE HEAT INDEX VALUES WILL ONCE AGAIN PUSH THE CENTURY MARK. HOWEVER...CLOUDS AND PRECIP SHOULD KEEP HI FROM REACHING ADVISORY CRITERIA. TRUETT .LONG TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 311 AM CDT WED JUL 10 2013 TONIGHT...SCT TSRA ALONG A CDFNT SHOULD DIMINISH WITH TIME THIS EVENING AS THE BDRY MOVES THROUGH THE AREA AND EVENTUALLY STALLS IN AR. THU THROUGH SAT...A COOLER AND DRIER AIR MASS WILL SPREAD ACROSS MO/IL BEHIND THE AFOREMENTIONED CDFNT...BRINGING A SHORT BREAK FROM THE RECENT HOT AND HUMID CONDITIONS. COOLER AND DRIER WX WILL PERSIST UNTIL THE SFC HIGH OVER IA/WI/IL SHIFTS EWD AND THE STRONG UPPER RIDGE OVER THE SWRN CONUS BUILDS INTO THE CENTRAL PLAINS. SUN THROUGH TUE...A 594+ DAM H5 PRESSURE CENTER IS FCST TO BE LOCATED OVER THE CENTER OF THE COUNTRY BY EARLY NEXT WEEK. THIS WILL BRING A RETURN OF HOT WEATHER TO THE AREA WITH LIMITED OPPORTUNITIES FOR PCPN. MODELS ARE FCSTG A BROAD AREA OF FAIRLY WEAK VORTICITY TO BREAK OFF FROM THE ERN CONUS TROF AND THEN MOVE WWD ACROSS THE SRN CONUS ON THE SOUTH SIDE OF THE HIGH. DEPENDING ON THE DETAILS...THIS FEATURE COULD PROVIDE JUST ENOUGH SUPPORT FOR ISO-SCT PCPN ACROSS THE SRN CWA. AS HAS BEEN THE CASE FOR THE LAST SEVERAL DAYS...MODELS CONTINUE TO SHOW A CLOSED LOW DVLPG SOMEWHERE ALONG THE APPALACHIANS...BUT THERE HAS BEEN LITTLE RUN TO RUN CONSISTENCY SO FAR. KANOFSKY && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 658 AM CDT WED JUL 10 2013 COVERAGE OF ELEVATED CONVECTION HAS RAPIDLY INCREASED OVER THE LAST FEW HOURS...BUT STILL EXPECTING THIS ACTIVITY TO SHIFT TO THE SE DURING THE MORNING. APPROXIMATE BACK EDGE OF THE PRECIP IS NEAR A BOONEVILLE...UIN LINE...SO WHILE COU WILL BE OUT OF THE THUNDER THREAT SHORTLY STL AREA TAFS WILL REMAIN WITH TEMPOS FOR TSRA UNTIL LATE MORNING. PREVAILING CONDITIONS WILL BE VFR CIGS AOA 5KFT...BUT WITH THE HIT AND MISS STRONG CORES VSBYS WILL CERTAINLY DROP TO IFR...WITH CIGS AT LEAST DIPPING INTO THE MVFR RANGE. WILL BE WATCHING RADAR TRENDS TO DETERMINE IF AMENDMENTS WILL BE NECESSARY FOR THESE LOWER CONDITIONS. STILL UNCERTAIN HOW ANY ADDITIONAL ACTIVITY WILL EVOLVE BY THIS AFTERNOON...BUT IN SPITE OF WEAKENING CONVERGENCE ALONG FRONT AND WITH BOUNDARY FROM THIS MORNINGS ACTIVITY SETTING UP S OF OUR CWA...THINK THAT REDEVELOPMENT MAY STILL OCCUR NEAR THE SYNOPTIC FRONT DUE TO RESIDUAL INSTABILITY AND WEAK UPPER LEVEL DYNAMICS DIPPING INTO THE AREA. SO...FOLLOWING THE LEAD OF THE LATEST HRRR DATA WILL REINTRODUCE VCTS IN STL FOR A BRIEF PERIOD EARLY THIS AFTERNOON...BEFORE FROPA PUSHES ACTIVITY S INTO SE MO/S IL. TRANQUIL CONDITIONS SHOULD PREVAIL THROUGHOUT THE AREA THIS EVENING...WITH CLEAR SKIES AND NORTH WINDS AOB 10 KTS. SPECIFICS FOR KSTL... BASED ON ABOVE REASONING WILL BE CARRYING TEMPO TSRA THROUGH 15Z WITH VFR CIGS AND MVFR VSBYS....BUT AS MENTIONED WILL BE WATCHING RADAR TRENDS TO DETERMINE IF MORE INTENSE CORES WILL IMPACT THE TERMINAL AREA. PRECIP THREAT SHOULD BRIEFLY LULL BEFORE REINTRODUCTION OF TSRA AS FRONTAL BOUNDARY MOVES THROUGH IN THE 18-20Z TIME FRAME...BUT AFTER 20Z FRONT SHOULD BE FAR ENOUGH SOUTH THAT THREAT WILL END. LATE AFTERNOON AND INTO THE EVENING SHOULD GENERALLY BE CLEAR/VFR...WITH LIGHT NORTH WINDS 5-10KTS. TRUETT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
642 AM CDT WED JUL 10 2013 .SYNOPSIS... ISSUED AT 313 AM CDT WED JUL 10 2013 THE 07Z MSL ANALYSIS SHOWED TWO MAIN BOUNDARIES ACROSS THE PLAINS. ONE WAS THE SURFACE FRONT FROM A LOW IN SOUTHEAST COLORADO ACROSS OKLAHOMA TO SOUTHWEST MISSOURI. THE OTHER WAS A TROUGH WITH ITS PRESENCE BETRAYED BY WIND FIELDS ACROSS SOUTHWEST NEBRASKA. SATELLITE DERIVED PRODUCT IMAGERY...WHERE IT WAS NOT POLLUTED WITH CLOUD...SHOWED AN AXIS OF MAXIMUM PRECIPITABLE WATER AND INSTABILITY FROM EAST CENTRAL WYOMING ACROSS THE NEBRASKA PANHANDLE AND SOUTHWEST NEBRASKA TO SOUTHEAST NEBRASKA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED JUL 10 2013 ONCE AGAIN...THE LOCATIONS OF CONVECTIVE DEVELOPMENT WILL DEPEND ON THE LOCATIONS OF THE FRONT AND OTHER BOUNDARIES FROM CONVECTION OVERNIGHT. IT IS DIFFICULT TO FIND ANY CONSENSUS AMONG THE AVAILABLE MODELS WITH THE SHORT RANGE FORECAST. THE RAP13 AND HRRR SEEM TO BE ON THE SAME PAGE WITH CONVECTION DEVELOPING FAIRLY EARLY TODAY IN WESTERN NEBRASKA. THE GEM REGIONAL AND THE GFS SEEM TO FAVOR THIS EVENING AND LATE NIGHT FOR THE TIMING. AS WAS THE CASE YESTERDAY...THE LOCATION OF BOUNDARIES AND THE FRONT IS A LITTLE UP IN THE AIR. AT FIRST...CENTRAL AND SOUTHWEST NEBRASKA APPEARS TO BE THE LOCATION TO WATCH WHERE THERE WAS CONVECTION YESTERDAY EVENING. LOOKING AT THE RAP13 CONVECTIVE PARAMETERS...THE SURFACE-BASED CONVECTIVE INHIBITION APPROACHES ZERO J/KG BY LATE MORNING TO EARLY AFTERNOON IN THE SOUTHWEST. ALSO...CONVECTIVE POTENTIAL ENERGY OF 1500-2500J/KG AND SFC-6KM BULK SHEAR INCREASING TO 40-50KT COULD SUPPORT LARGE HAIL. FOR LATER PERIODS...THE FRONT LIFTING ONTO THE HIGH PLAINS WOULD BE A GOOD FOCUS FOR CONVECTION TO DEVELOP THIS EVENING OR OVERNIGHT AS IT MOVES INTO WESTERN NEBRASKA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 313 AM CDT WED JUL 10 2013 THE EXPANSIVE RIDGE OF HIGH PRESSURE THAT HAS BEEN ANCHORED ACROSS THE FOUR CORNERS REGION FOR DAYS...WILL BUILD NORTH OVER OUR AREA THURSDAY INTO FRIDAY. THIS WILL BRING WARMING TEMPERATURES ALOFT...WHICH WILL CAP THE ATMOSPHERE...AND LITTLE IN THE WAY OF T-STORM ACTIVITY IS EXPECTED. IT WILL BE QUITE HOT AS WELL...WITH HIGHS IN THE 90S TO AROUND 100 DEGREES. HUMIDITY WILL REMAIN AS WELL...ESPECIALLY EAST OF HIGHWAY 83...AND A HEAT ADVISORY MAY BE NEEDED FRIDAY AND POSSIBLE SATURDAY. BY LATER SATURDAY INTO SUNDAY...A SHORTWAVE WILL SKIRT ACROSS CANADA. THIS WILL DRIVE A COLD FRONT SOUTH INTO THE REGION...WITH RETURNING CHANCES FOR T-STORMS WITH THE ARRIVAL OF THE FRONT. THE UPPER LEVEL HIGH WILL ALSO BE TEMPORALLY SUPPRESSED SOUTH...WITH TEMPERATURES COOLING JUST A FEW DEGREES. THE RIDGE IS FORECASTED TO BUILD OVERHEAD AGAIN BY TUESDAY INTO WEDNESDAY...WITH HOT WEATHER CONTINUE AND ONLY AN ISOLATED T-STORM AT BEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 640 AM CDT WED JUL 10 2013 ISOLATED THUNDERSTORMS DEVELOPING IN WESTERN NEBRASKA THIS MORNING WILL INCREASE IN COVERAGE AND SPREAD EAST TO CENTRAL AND SOUTHWEST NEBRASKA BY MID-AFTERNOON. THE STORMS MAY AFFECT MHN...TIF...BBW... LBF...OGA AND IML. HOWEVER...WITH LIMITED COVERAGE...THE PROBABILITY IS NOT HIGH ENOUGH TO INCLUDE IN THE TERMINAL FORECAST FOR LBF. EXCEPT IN AND NEAR THUNDERSTORMS...CEILING AND VISIBILITY WILL NOT RESULT IN ANY LIMITATIONS TO FLIGHT OPERATIONS. LIGHT AND VARIABLE WIND WILL BECOME SOUTHEAST AND INCREASE TO 10-15G17-22KT. IN THE VICINITY OF THUNDERSTORMS WIND WILL BE VRB20-26G34-45KT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SPRINGER SHORT TERM...SPRINGER LONG TERM...TAYLOR AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1009 AM EDT WED JUL 10 2013 .SYNOPSIS... WATCH FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS MUCH OF THE NORTH COUNTRY THIS AFTERNOON AND EVENING. ANY STORMS WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AND VERY HEAVY RAINFALL THAT COULD LEAD TO FLASH FLOODING. THUS A FLASH FLOOD WATCH REMAINS IN EFFECT THIS AFTERNOON THROUGH MIDNIGHT. THE THREAT FOR PRECIPITATION WILL BE LIMITED TO EASTERN VERMONT ON THURSDAY AND THEN DRY WEATHER WITH SEASONAL TEMPERATURES IS EXPECTED FOR THE WEEKEND. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 1009 AM EDT WEDNESDAY...UPDATE TO POPS THROUGH THE DAY BASED OFF CURRENT RADAR ACTIVITY AND BLEND OF AVAILABLE CAM MODEL OUTPUT. STILL LOOKING MORE OR LESS AT 40/70% POPS ACROSS THE AREA TODAY...BUT DETAILED CURRENT BAND PROGRESSING EAST ACROSS CENTRAL NY MOVING INTO THE AREA A TAD BETTER AND AS RESOLVED QUITE WELL BY LATEST HRRR DATA. REST OF FORECAST REMAINS MORE OR LESS IN GOOD SHAPE. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS... GOING FORECAST IN GOOD SHAPE AND NO CHANGES NEEDED AT THIS TIME. THREAT FOR FLASH FLOODING AND STRONG GUSTY WINDS WILL REMAIN ACROSS MUCH OF THE AREA THIS AFTERNOON AND EVENING. COMPOSITE ANALYSIS SHOWS STRONGEST DYNAMIC SUPPORT AND DEEP LAYER SHEAR WILL REMAIN ACROSS EASTERN CANADA THIS AFTERNOON AND EVENING AS LARGE UPPER TROUGH MOVES INTO THE AREA. LATER THIS AFTERNOON HOWEVER...THE SOUTHERN END OF THE STRONGER FLOW ALOFT...25 KNOTS AT 850 MB AND 30 KNOTS AT 500 MB WILL MOVE ACROSS THE SOUTHERN HALF OF VERMONT THIS AFTERNOON. THIS COMBINED WITH CONVECTIVE AVAILABLE POTENTIAL ENERGY APPROACHING 1000 J/KG SUGGEST SOME ORGANIZATION TO THE STORMS WILL EXIST. THUS LOOKING AT PULSE/MULTICELL STORMS LATER THIS AFTERNOON AND EVENING WITH THE AREA FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY AS THE MAIN AREA OF CONCERN. AXIS OF HIGH PRECIPITABLE WATER AIR...VALUES AROUND 2 INCHES...WILL NOSE RIGHT UP INTO THE AREA. SO WITH STORM MOTIONS UNDER 15 KNOTS...THE THREAT FOR HEAVY DOWNPOURS AND FLASH FLOODING WILL EXIST ESPECIALLY SINCE THE AREA COVERAGE OF STORMS WILL BE GREATER THAN THE PAST COUPLE OF DAYS. THUS GOING IDEA OF A FLASH FLOOD WATCH FOR MOST OF THE AREA STILL LOOKS GOOD. IN ADDITION...FEEL WITH SOME ORGANIZATION TO THE STORMS...THREAT FOR STRONG GUSTY WINDS WILL EXIST. HAVE INCLUDED THE ENHANCED WORDING IN THE FORECAST FOR THESE TWO THREATS. WE MAY SEE CLOUDS AND SPOTTY SHOWERS MOVE ACROSS THE AREA THIS MORNING...BUT MAIN THREAT FOR STORMS WILL BE AFTER 200 PM. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... AS OF 437 AM EDT WEDNESDAY...ACTIVE WEATHER WITH STORMS POTENTIALLY PRODUCING FLASH FLOODING WILL EXIST THROUGH MIDNIGHT TONIGHT...THEN INTENSITY OF STORMS WILL WEAKEN OVERNIGHT AND MOVE EAST OF THE AREA. COLD FRONT WILL BECOME PARALLEL TO THE UPPER FLOW ON THURSDAY AND THUS THE FRONT WILL STILL HANG AROUND EASTERN VERMONT FOR A CONTINUED CHANCE OF SHOWERS OR STORMS. HIGH PRESSURE BUILDS IN LATE THURSDAY NIGHT AND FRIDAY FOR DRIER WEATHER AND TEMPERATURES TRENDING SLIGHTLY BELOW NORMAL BY FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 437 AM EDT WEDNESDAY...THE PATTERN CHANGE TO A WESTERLY FLOW OF DRIER WEATHER WILL PERSIST FRIDAY NIGHT THRU TUESDAY WITH A WARMING TREND. HIGH PRESSURE WILL PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK WITH UPPER LEVEL RIDGING AND A NW TO W FLOW ALOFT. DO NOT SEE ANY SIGNIFICANT CHANCE FOR PRECIPITATION IN THE EXTENDED. STILL LOTS OF UNCERTAINTY THAT FAR OUT...BUT GFS AND NAM BOTH HINT AT SOME SHOWERS AROUND FRIDAY NIGHT AND SATURDAY. HAVE LEANED TOWARDS DRIER ECMWF AT THIS POINT. TEMPERATURES WILL START OUT SLIGHTLY BELOW NORMAL...BUT TREND BACK OVER NORMAL TOWARDS THE END OF THE PERIOD. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THROUGH 12Z THURSDAY...SOME MVFR CEILINGS THIS MORNING WITH LINE OF LIGHT RAIN SHOWERS MOVING INTO WESTERN VERMONT CURRENTLY. WEAK BOUNDARY WITH EVEN MORE HUMID AIR ASSOCIATED WITH APPROACHING FRONTAL SYSTEM AROUND WITH CHANCE OF SHOWERS...PERHAPS A RUMBLE OF THUNDER SO HAVE INCLUDED VCSH. OTHERWISE UNSTABLE AIR WILL BE GENERATING WIDESPREAD SHOWERS AND THUNDERSTORMS BY 18Z OR SO. HAVE INCLUDED VCTS AT ALL SITES AFTER 18Z WED. WINDS WILL BE INCREASING FROM THE S-SW ON WED WITH 10-15 KNOTS SUSTAINED AND GUSTS 15 TO 25 KNOTS ESPECIALLY BTV-MSS. AFTER 00Z SHOWERS AND THUNDERSTORMS SHOULD DIE DOWN WITH LOSS OF DAYTIME HEATING. OUTLOOK 12Z THURSDAY THROUGH SUNDAY...THU...MAINLY VFR AFTER SOME EARLY MORNING SHOWERS AND FOG. FRI-SUN...MAINLY VFR WITH NORTHERLY FLOW AND HIGH PRESSURE. && .HYDROLOGY... AS OF 437 AM EDT WEDNESDAY...ONCE AGAIN WE SAW ISOLATED STORMS PRODUCE FLASH FLOODING ON TUESDAY. CONDITIONS FOR MORE FLASH FLOODING WILL EXIST THIS AFTERNOON AND EVENING AND THE POTENTIAL FOR FLASH FLOODING MAY ACTUALLY BE GREATER SIMPLY FOR THE FACT THAT THERE WILL BE MORE STORMS AROUND THAN THE PAST COUPLE OF DAYS. EXPECT SCATTERED TO NUMEROUS THUNDERSTORMS DEVELOPING OVER THE AREA THIS AFTERNOON...ESPECIALLY FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY. THE DEEP LAYER OF MOISTURE IN THE ATMOSPHERE OVER THE REGION COMBINED WITH SLOW MOVING STORMS SUGGESTS FLASH FLOODING IS POSSIBLE. THUS WILL KEEP THE FLASH FLOOD WATCH IN PLACE. POTENTIAL IMPACTS INCLUDE WASHED OUT AND FLOODED ROADS...FIELD FLOODING...RAPID RISES ON SMALLER RIVERS AND STREAMS. && .MARINE... AS OF 436 AM EDT WEDNESDAY...ACTIVE WEATHER IS EXPECTED ACROSS LAKE CHAMPLAIN TODAY THROUGH THIS EVENING. FIRST EXPECT STRONGER WINDS OVER THE LAKE WITH SOUTH WINDS INCREASING INTO THE 20 TO 30 KNOT RANGE BY AFTERNOON AND NOT DECREASING UNTIL AFTER MIDNIGHT TONIGHT. THESE WINDS ARE STRONGER THAN WHAT HAS BEEN FELT OVER THE LAKE THE PAST FEW DAYS. THUS A LAKE WIND ADVISORY IS IN EFFECT. IN ADDITION...EXPECT THUNDERSTORMS TO DEVELOP OVER NORTHERN NEW YORK THIS AFTERNOON AND MOVE EAST ACROSS LAKE CHAMPLAIN. BE AWARE THAT ANY STORMS WILL HAVE THE POTENTIAL TO PRODUCE STRONG GUSTY WINDS AND AS WE HAVE SEEN THE PAST MONTH OR SO...VERY HEAVY DOWNPOURS. && .EQUIPMENT... AS OF 436 AM EDT WEDNESDAY...THE KTYX RADAR IS DOWN UNTIL FURTHER NOTICE. TECHS HAVE ORDERED PARTS...THOUGH RETURN TO SERVICE IS UNKNOWN AT THIS TIME. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VTZ001>012-016>019. NY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NYZ028>031-034-035. && $$ SYNOPSIS...EVENSON NEAR TERM...JMG/EVENSON SHORT TERM...EVENSON LONG TERM...NEILES AVIATION...NEILES HYDROLOGY..EVENSON MARINE...EVENSON EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1045 AM EDT WED JUL 10 2013 .SYNOPSIS... A SERIES OF WEAK DISTURBANCES ALOFT WILL CROSS THE MIDDLE ATLANTIC REGION THROUGH TONIGHT. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM WEDNESDAY... ANOTHER UNSETTLED AFTERNOON AND EVENING EXPECTED ACROSS CENTRAL NC WITH A CONSIDERABLE AMOUNT OF CLOUDINESS AND A COUPLE OF FAVORED REGIONS FOR CONVECTION. MORNING UPPER AIR ANALYSIS AND SATELLITE IMAGERY DEPICTS A LINGERING SHEAR AXIS DRAPED NORTHEAST TO SOUTHWEST FROM KECG TO KGSB TO KLBT. THE RAP SUGGESTS THIS FEATURE WILL DRIFT EAST SLIGHTLY AND WOULD FAVOR CONVECTION ACROSS THE EASTERN THIRD OF THE RAH CWA. ANOTHER REGION FAVORED FOR CONVECTION WILL BE THE ACROSS THE FOOTHILLS OF NC/VA WHERE AN APPROACHING TROUGH AXIS WILL INITIATE CONVECTION THAT IS PROGGED BY MANY CONVECTION ALLOWING MODELS TO DEVELOP INTO A MORE LINEAR/MULTI-CELL SYSTEM THAT WILL LIKELY MOVE INTO WESTERN/NORTHERN PARTS OF THE RAH CWA LATE THIS AFTERNOON AND EVENING. THE AIR MASS ACROSS CENTRAL NC IS WET WITH PW VALUES AROUND 1.75 INCHES. MODERATE INSTABILITY WITH UNIMPRESSIVE LAPSE RATES IN A WEAK SOUTHWESTERLY FLOW SHOULD LIMIT THE SEVERE THREAT TO A FEW STORMS WITH DOWNBURST WINDS FROM PRECIP LOADING WITH LOCALIZED FLOODING IN SLOW MOVING STORMS A MORE NOTEWORTHY THREAT. CURRENT FORECAST OF HIGHS IN THE UPPER 80S TO AROUND 90 AND LOWS IN THE LOWER 70S LOOKS GOOD. -BLAES && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 320 AM WEDNESDAY... THE FLOW ALOFT WILL UNDERGO SIGNIFICANT AMPLIFICATION THIS PERIOD... HIGHLIGHTED FOR CENTRAL NC BY A SHARP...POSITIVELY TILTED TROUGH AXIS FROM EASTERN CANADA SSW TO THE LOWER MS VALLEY. MOIST SW FLOW ALOFT AND STRONG QG FORCING FOR ASCENT ASSOCIATED WITH THE TROUGH/UPPER JET...IN ADDITION TO THE THU NIGHT ARRIVAL OF AN ACCOMPANYING SURFACE COLD FRONT...WILL YIELD NUMEROUS TO WIDESPREAD SHOWERS AND STORMS THU AFTERNOON AND THROUGHOUT THE NIGHT... INCLUDING A PROBABLE LOOSELY-ORGANIZED LINE OF STORMS...WITH HEAVY RAIN AND A FEW STRONG WIND GUSTS...AHEAD OF/ALONG THE FRONT. A WIDESPREAD SOAKING RAIN OF ONE HALF TO ONE INCH IS LIKELY...WITH LOCALLY MUCH HIGHER AMOUNTS WHERE THE (EFFECTIVE) FRONTAL CONVECTION OVERLAPS EARLIER AFTERNOON AND EVENING WARM-SECTOR STORMS. SIMILAR TEMPERATURES TO PREVIOUS DAYS...GENERALLY UPPER 80S TO AROUND 90...AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 305 AM WEDNESDAY... A COUPLE POTENTIAL HAZARDS IN THE EXTENDED PERIOD OF THE FORECAST INCLUDING THE FLASH FLOODING POTENTIAL AND THE FORECAST OF CURRENT CHANTAL. FIRST... ANTECEDENT CONDITIONS CONTINUE PRIMED FOR FLASH FLOODING. IT APPEARS THAT THE FLASH FLOOD THREAT WILL BE SHIFTING TO THE SE QUADRANT OF NORTH CAROLINA BY FRIDAY. MODELS ARE IN GOOD AGREEMENT IN PLACING THE COLD FRONT OVER CENTRAL NC 12Z FRIDAY... GRADUALLY DRIFTING SE INTO SE NC DURING THE DAY. THIS SUPPORTS THE HEAVIEST QPF IN A SW-NE AXIS ACROSS THE SANDHILLS INTO THE COASTAL PLAIN... SLIDING SE WITH TIME FRIDAY. THIS FORECAST IS MODERATE TO HIGH CONFIDENCE GIVEN SUPPORT FROM TRENDS AND ENSEMBLE FORECASTS AS WELL. THEREFORE... WE WILL CONTINUE TO LOWER POP IN THE NW... AND CONTINUE WITH SHOWERS AND THUNDERSTORMS LIKELY IN THE SE... WITH MORE SCATTERED SHOWERS AND THUNDERSTORMS IN THE MIDDLE OF THE STATE. QPF OF AN INCH OR SO APPEARS REASONABLE FROM 12Z FRIDAY TO 12Z SATURDAY IN THE SE... WITH LOCALLY 2 INCHES IN THE STRONGER STORMS FRIDAY AFTERNOON. LESSER QPF WITH LESS THAN 0.25 EXPECTED IN THE NW PIEDMONT. PARTLY TO MOSTLY CLOUDY SKIES FRIDAY NIGHT... WITH ISOLATED ACTIVITY IN THE NW... AND SCATTERED IN THE SE. HIGHS FRIDAY IN THE LOWER TO MID 80S. LOWS FRIDAY NIGHT UPPER 60S TO LOWER 70S. SATURDAY THROUGH TUESDAY... A TRANSITION PERIOD WITH THE FATE OF CHANTAL ESSENTIALLY TO BE DETERMINED. AFTER THE STALLED BOUNDARY ESSENTIALLY WASHES OUT OVER SE NC THIS WEEKEND... WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS BOTH SAT-SUN... MUCH OF NEXT WEEK APPEARS THAT IT WILL BE MORE MID-JULY LIKE... AS MODELS DEPICT ABOVE NORMAL HEIGHTS OVER MOST OF THE U.S. HOWEVER... A LINGERING WEAKNESS EARLY IN THE WEEK WILL LIKELY SPELL A CONTINUATION OF SCATTERED DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS OVER OUR REGION MONDAY AND TUESDAY. A WILD CARD CONTINUES TO BE THE FATE OF CURRENT TROPICAL STORM CHANTAL. OBVIOUSLY THIS WILL BE MONITORED CLOSELY AND THE FORECASTS FROM THE NHC WILL BE FOLLOWED EXPLICITLY. IN THOSE REGARDS... IF THE SYSTEM AFFECTS OUR REGION DIRECTLY OR INDIRECTLY... IT WOULD MOST LIKELY BE EARLY NEXT WEEK. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... AS OF 725 AM TUESDAY... PERSISTENCE. CONTINUED VERY HUMID SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE WILL MAINTAIN A FAMILIAR PATTERN CONSISTING OF EARLY MORNING (V)LIFR CEILINGS THAT WILL GRADUALLY LIFT AND SCATTER THROUGH MVFR RANGE...TO VFR...THROUGH 16-18Z. VFR CONDITIONS SHOULD THEN PREVAIL OUTSIDE OF SCATTERED SHOWERS AND STORMS THIS AFTERNOON AND EVENING...MOST LIKELY AT KFAY/KRWI/KRDU BETWEEN 17-22Z...AND AT TRIAD TERMINALS (KGSO/KINT) BETWEEN 21Z-02Z. SOME CONVECTION IS LIKELY TO LINGER OVERNIGHT...IN RESPONSE TO AN APPROACHING STRONG UPPER LEVEL TROUGH AND ASSOCIATED LIFT. LIFR CEILINGS SHOULD THEN REDEVELOP IN THE VERY HUMID REGIME LATE TONIGHT-EARLY THU. OUTLOOK... MORE OF THE SAME EXPECTED THROUGH THE WEEKEND...WITH SHOWER AND STORM COVERAGE MAXIMIZED LATE THU AND THU NIGHT...AND THROUGH FRI AT EASTERN TAF SITES...OWING TO THE APPROACH AND PASSAGE OF AN UPPER LEVEL TROUGH AND SURFACE COLD FRONT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...BLAES SHORT TERM...MWS LONG TERM...BADGETT AVIATION...MWS
AREA FORECAST DISCUSSION
NWS PORTLAND OR
834 AM PDT WED JUL 10 2013 .SYNOPSIS...A SERIES OF WEAK UPPER TROUGHS WILL REINTRODUCE ONSHORE FLOW AND DRY AND MILD WEATHER OVER SOUTHWEST WASHINGTON AND NORTHWEST OREGON THROUGH THE REMAINDER OF THE WEEK. THESE SYSTEMS WILL DEEPEN THE MARINE LAYER AND DROP INLAND TEMPS TO NEAR OR A BIT BELOW NORMAL....WITH VARYING DEGREES OF INLAND MORNING CLOUDS. ANY CHANCE OF THUNDERSTORMS WILL BE SOUTH AND EAST OF OUR FORECAST AREA. WE MAY GET SOME WARMING AGAIN EARLY NEXT WEEK. && .SHORT TERM....CLOUDS MADE IT INTO THE COAST RANGE GAPS BUT THE MARINE LAYER IS SHALLOW... THUS MOST LOW CLOUDINESS INLAND IS CONFINED TO THE COLUMBIA RIVER GAP WITH SOME POCKETS AROUND THE S WA FOOTHILLS AND NEAR THE GORGE. FAVOR THE TEMPS CLOSER TO WARMER EC/MAV GUIDANCE WITH LESS CLOUD COVER OBSERVED...AND THIS COVERED REASONABLY WELL IN CURRENT FCST. HI RESOLUTION GUIDANCE FROM THE HRRR AND 4 KM WRF SUGGEST THUNDERSTORMS TODAY WILL REMAIN EAST OF THE CASCADE CREST. SPC HAS A GENERAL THUNDER JUST SOUTH AND EAST OF THE LANE COUNTY CASCADES. WE MAY STILL SEE SOME CUMULUS BUILDUPS OR PASSING HIGH CLOUDS ALONG THE LANE COUNTY CASCADES...POSSIBLY A BIT FURTHER NORTH...IN RESPONSE TO THE INLAND PROPAGATING DISTURBANCE CURRENTLY OFF THE NORTHERN CALIFORNIA COAST. SW FLOW AHEAD OF THIS DAMPENING WAVE IS CONSISTENT WITH THIS SIGNAL IN PUSHING CONVECTION EAST. MODELS SUGGEST A STRONGER MARINE PUSH TONIGHT INTO THURSDAY MORNING. EXPECT LOW CLOUDS TO PUSH INTO THE CASCADE FOOTHILLS THROUGH THURSDAY MORNING...WITH MORE COVERAGE FOR THE VALLEY. EXPECT THE MOST COVERAGE FOR THE NORTH COAST RANGE AND INTO THE NORTH VALLEY AS THE UPPER WAVES OFFSHORE CONSOLIDATE. WE WILL FEEL THE IMPACTS OF THE NORTHERN WAVE THE MOST...AND SINCE IT PASSES BY THROUGH WASHINGTON...THE MARINE LAYER WILL BE DEEPEST NORTH. WITH THIS DEEPER LAYER AND THE WAVE MOVING THROUGH...SOME PATCHY DRIZZLE IS EXPECTED ALONG THE NORTH COAST/COAST RANGE. WE REMAIN UNDER THE INFLUENCE OF BROAD TROUGHINESS....WITH VARYING DEGREES OF MORNING CLOUDS AND AFTERNOON SUN FRIDAY AND SATURDAY. KMD .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY EVENING THROUGH MONDAY...THE MEDIUM RANGE MODELS SHOW A SHORTWAVE TROUGH COMING THROUGH THE FCST LATE FRI OR EARLY SAT. THE TROUGH IS SHARP ENOUGH THAT A SLIGHT CHC OF SPRINKLES OR DRIZZLES WAS ADDED TO THE FCST FOR THE COAST AND COAST RANGE OVERNIGHT FRI INTO SAT MORNING. SAT LOOKS TO BE A TRANSITION DAY...WITH PLENTY OF CLOUDS BUT TEMPS WARMING BACK TO NEAR SEASONAL AVGS. THEN A LARGE UPPER LEVEL RIDGE OVER THE CENTRAL U.S. WILL BUILD TOWARDS THE PAC NW BRINGING MORE SUN AND ABOVE AVERAGE TEMPS FOR SUN INTO EARLY NEXT WEEK. THE LATEST MODEL TRENDS INDICATE THAT THE STRENGTH OF THE RIDGE WILL NOT BE QUITE AS STRONG AS PREVIOUS RUNS WERE INDICATING. HOWEVER...ON THE WARMEST DAYS OF SUN AND MON INTERIOR LOWLAND SITES MAY STILL APPROACH 90 DEG. PYLE && .AVIATION...NORTHERLY SURFACE WINDS WILL KEEP THE MUCH OF THE OREGON COAST UNDER LOWER CIGS TODAY. EXPECT THE S WA AND N OREGON COAST WILL BE LOW-END MVFR THROUGH AT LEAST 19Z. AREAS S OF KTMK EXPECTED TO CLEAR AFTER 19Z...BUT NOT AS CONFIDENT N OF KTMK. OTHERWISE...CLEAR SKIES INLAND TODAY. MARINE LAYER PUSHES INLAND TONIGHT. KPDX AND APPROACHES...VFR UNDER CLEAR SKIES TODAY. MARINE LAYER RETURNS TONIGHT...FOR MVFR CONDITIONS FROM AROUND 12Z THROUGH 18Z THU. && .MARINE...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. SIMILAR PATTERN FOR THE NEXT FEW DAYS. BASED ON CONDITIONS TUE DECIDED TO GO WITH A SMALL CRAFT ADVISORY FOR WIND IN THE N WATERS FROM 18Z TODAY THROUGH 09Z THU. GRADIENT EASES A BIT THU. SRN WATERS WILL CONTINUE WITH THE PERSISTENT 25 KT GUSTS FROM LATE-MORNING THROUGH LATE-EVENING. CONTINUAL SHORT-PERIOD AND MOSTLY WIND-DRIVEN SEAS FOR THE NEXT FEW DAYS. OVERALL WAVE HEIGHTS AND STEEPNESS PARAMETERS TO REMAIN BELOW ADVISORY THRESHOLDS. WEISHAAR && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 AM PDT THURSDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM. SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT THURSDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM. && $$ MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWS.PORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
648 AM CDT WED JUL 10 2013 .AVIATION... FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID FORECAST PERIOD. A SMALL CHANCE OF AFTERNOON STORMS NEAR THE DFW METROPLEX IS THE PRIMARY AVIATION WEATHER CONCERN. HIGH PRESSURE REMAINS IN PLACE OVER THE REGION WHICH WILL HELP MAINTAIN VFR CONDITIONS THROUGH THE FORECAST PERIOD. THUNDERSTORM ACTIVITY THAT OCCURRED OVER THE CENTRAL PLAINS EARLY THIS MORNING IS EXPECTED TO DISSIPATE WITH THEIR REMNANTS MOVING SOUTH TOWARDS NORTH TX THIS AFTERNOON. WITH 100 DEGREE HEAT EXPECTED...THE LATEST RAP FORECAST SOUNDINGS INDICATE AN UNCAPPED ENVIRONMENT FOR THUNDERSTORMS ALL AROUND THE DFW METROPLEX THIS AFTERNOON. ANY WEAK LIFT MAY BE SUFFICIENT TO CAUSE ISOLATED STORMS TO DEVELOP NEAR DFW AREA AIRPORTS DURING THE PEAK HEATING HRS OF THE DAY. CONFIDENCE IN THE REMNANTS OF THE CENTRAL PLAINS THUNDERSTORM ACTIVITY PROVIDING THIS LIFT REMAINS LOW...SO DO NOT HAVE A MENTION OF STORMS IN THE TAFS AT THIS TIME. SEVERAL HIGH RESOLUTION MODELS PRODUCE ISOLATED STORMS NEAR I-20 THIS AFTERNOON SO WILL HAVE TO WATCH SATELLITE IMAGERY CLOSELY FOR ANY SIGNS THAT A STORM WILL DEVELOP NEAR AREA AIRPORTS. DOWNBURST WINDS AND CLOUD TO GROUND LIGHTNING ARE THE EXPECTED IMPACTS FROM ANY THUNDERSTORMS. THUNDERSTORM CHANCES ARE EXPECTED TO DIMINISH AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. CAVANAUGH && .PREV DISCUSSION... /ISSUED 254 AM CDT WED JUL 10 2013/ BASED ON SOME DEEPER MOISTURE AND FORECAST CONVECTION EVIDENT ON THE RAP/NAM/TTU WRF/4KM WRF/HRRR...WE HAVE ADDED LOW POPS TO THE NORTH AND NORTHEAST THIS AFTERNOON. THERE IS ALSO SOME WEAK UPPER SUPPORT IN THE FORM OF A SHORT WAVE MOVING SOUTH DOWN THE BACK SIDE OF THE UPPER RIDGE THIS AFTERNOON. THIS DISTURBANCE IS ASSOCIATED WITH THE CURRENT CONVECTION IN KANSAS/MISSOURI. FOR THURSDAY...AFTERNOON/EVENING CONVECTION IN THE NORTHEAST NEAR A WEAK BACKDOOR FRONT STILL LOOKS PLAUSIBLE. BY FRIDAY THE RIDGE STARTS BUILDING BACK OVER NORTH TX SO ANY PRECIP SHOULD BE CONFINED TO FAR EASTERN COUNTIES. ON SATURDAY SOME OF THE DRIEST AIR OF THE WEEK MOVES ACROSS THE AREA. BY SATURDAY AFTERNOON DEW POINTS SHOULD DROP INTO THE 50S ACROSS MUCH OF THE AREA AS THE SHALLOW GULF MOISTURE MIXES WITH THIS DRY AIR ALOFT. THIS DRY AIR MASS WILL ALSO ALLOW A LITTLE EXTRA COOLING OVERNIGHT AND SUNDAY MORNING LOWS WILL BE ALMOST REFRESHING. IN THE EXTENDED...A TROPICAL LOW WILL MOVE INTO SOUTH TEXAS ON SUNDAY...AND WE SHOULD SEE SOME ISOLATED CONVECTION...AT LEAST IN THE SOUTH. COVERAGE IS LIKELY TO BE LOW AS WITH THE PREVIOUS SYSTEM THAT TOOK A SIMILAR PATH. GFS/ECMWF BOTH SHOW THAT BY SUNDAY MORNING A 500MB LOW OVER NEW YORK/NEW ENGLAND STARTS DROPPING SOUTH SOUTHWEST...REACHING MISSISSIPPI BY WEDNESDAY. THE ECMWF STALLS THIS LOW OVER THE LOWER MISSISSIPPI VALLEY...BUT THE GFS PUSHES IT WESTWARD ACROSS NORTH TX THU/FRI. IF THE LOW DOES MOVE INTO THE AREA...IT IS PROBABLY THE BEST CHANCE FOR MORE WIDESPREAD PRECIPITATION. THIS FAR OUT...HAVE KEPT THE POPS LOW AND WE WILL WAIT FOR A BETTER CONSENSUS. 84 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 101 79 101 78 100 / 20 20 20 20 10 WACO, TX 99 78 100 76 100 / 5 5 5 5 10 PARIS, TX 100 76 100 75 96 / 20 20 30 30 20 DENTON, TX 101 78 102 76 100 / 20 20 20 20 10 MCKINNEY, TX 100 78 101 76 99 / 20 20 30 30 10 DALLAS, TX 100 81 101 80 100 / 20 20 20 20 10 TERRELL, TX 99 78 100 76 99 / 20 20 20 20 10 CORSICANA, TX 99 77 100 76 100 / 10 10 10 10 10 TEMPLE, TX 98 75 99 74 100 / 5 5 5 5 5 MINERAL WELLS, TX 101 75 101 73 101 / 10 10 10 10 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1137 AM CDT WED JUL 10 2013 .UPDATE... THE COLD FRONT CONTINUES TO MOVE THROUGH SOUTHERN MISSOURI LATE THIS MORNING. A FEW LIGHT SHOWERS HAVE BEEN NOTED IN NORTHEAST SECTIONS. WILL KEEP THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA THIS AFTERNOON WITH BEST CHANCES CENTRAL AND SOUTH. INCREASED MAXIMUM TEMPERATURES A COUPLE OF DEGREES BASED ON OBS AND TRENDS. QUITE A BIT OF CLOUD COVER IS OVER THE NORTH FROM THE THUNDERSTORMS IN MISSOURI. && .PREV DISCUSSION... /ISSUED 637 AM CDT WED JUL 10 2013/ AVIATION... PREVALENT VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. CONVECTION IN SOUTHERN MISSOURI CONTINUES TO SLOWLY MOVE SOUTH AHEAD OF A FRONTAL BOUNDARY. THIS WILL DIMINISH SOMEWHAT IN THE NEXT FEW HOURS... BUT ADDITIONAL DEVELOPMENT WILL BE POSSIBLE LATER THIS MORNING AND INTO THE AFTERNOON HOURS. AT THIS POINT...HAVE CONTINUED TO MENTION VCTS IN THE NORTHERN SITES...BUT AS FOR THE CENTRAL AND SOUTH... NOT TOO CONFIDENT YET IF PRECIP WILL BE SEEN AT ALL...GIVEN THE EXPECTED SCATTERED NATURE OF THE PRECIP LATER TODAY. TAFS ALREADY OUT. PREV DISCUSSION... /ISSUED 331 AM CDT WED JUL 10 2013/ SHORT TERM...TODAY THROUGH SATURDAY NIGHT CONVECTION WAS ONGOING ACROSS PARTS OF SOUTHERN/CENTRAL MISSOURI EARLY THIS MORNING. FURTHER NORTH A FRONTAL BOUNDARY STRETCHED ACROSS NORTHERN KANSAS AND UP INTO SOUTHEASTERN IOWA. THE FORECAST TODAY IS SOMEWHAT TRICKY AS A RESULT OF THESE TWO FEATURES. THE ONGOING CONVECTION HAS SENT OUT SOME OUTFLOW BOUNDARIES THAT SHOULD WORK INTO NRN ARKANSAS BY MID MORNING. THE 4KM WRF AND ALSO THE RAPID REFRESH RUC SUGGEST THESE BOUNDARIES WILL LIKELY BE A FOCUS FOR MIDDAY AND AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY SOUTH OF THE I-40 CORRIDOR. HOWEVER THE FRONTAL BOUNDARY WILL MOVE IN DURING THE EVENING HOURS...UPON WHICH THE MORE COARSE MODELS SUGGEST WILL BE MORE DOMINANT SHOWER/THUNDERSTORM ACTIVITY. TRENDED THE FORECAST IN THE DIRECTION OF THE FORMER...WITH SLIGHTLY COOLER /WE ARE TALKING ABOUT 1-2 DEGREES HERE/ AFTERNOON HIGHS UP NORTH THAN GUIDANCE SUGGESTS...AND PLAYED RAIN CHANCES TOWARDS THE SOUTHERN ISOLD TO SCT VARIETY INSTEAD OF CONVECTION BEING TIED TO THE FRONT. THAT SAID...DID LEAVE SLIGHT CHANCES IN THE NORTH THROUGH THE DAY AND INTO TONIGHT TO ACCOUNT FOR CONVECTION ALONG THE FRONT. OTHERWISE...NOT MUCH TO TALK ABOUT IN THE EXTENDED. THE AFOREMENTIONED FRONT WILL PUSH WELL INTO THE STATE BY THURSDAY. UPPER LEVEL HIGH PRESSURE SITUATED OVER THE PLAINS WILL BECOME HIGHLY AMPLIFIED BY LATE THURSDAY. LEFT SOME SLIGHT RAIN CHANCES OVER THE FAR SOUTH AND FAR SOUTHWEST PARTS OF THE FORECAST AREA THU AND FRI AFTERNOONS. THERE IS SOME QPF SIGNAL IN NUMERICAL MODELS BOTH DAYS IN THOSE REGIONS...WHICH SEEMS REASONABLE. TEMPERATURES WILL NOT COOL DOWN MUCH IN THE SOUTHWEST...BUT HIGHS IN THE NORTHEAST BY FRIDAY WILL LIKELY NOT REACH 90 DEGREES. HOWEVER DRIER AIR WILL FILTER IN ACROSS ARKANSAS SO EVEN WITH HIGHS IN THE LOW 90S ACROSS THE SOUTHWEST HALF OF THE STATE...THERE WILL BE SOME RELIEF FROM THE HOT AND MUGGY CONDITIONS HEADING INTO THE WEEKEND. LONG TERM...SATURDAY NIGHT THROUGH TUESDAY THE LONG TERM OFFERS AN ODD SYNOPTIC SETUP FOR JULY. AT THE BEGINNING...THE RETROGRADING CUTOFF LOW WILL BE MOVING INTO COASTAL TEXAS...WITH AN ELONGATED UPPER RIDGE SETTING UP OVER THE PLAINS. THE AFOREMENTIONED LOW WILL BRING MOISTURE UP INTO THE REGION...AND WITH IT A CHANCE OF SHOWERS/STORMS EACH DAY...WHICH SHOULD MOSTLY BE DIURNALLY DRIVEN. WILL CONTINUE TO KEEP RAIN CHANCES SMALL TO ACCOUNT FOR UNCERTAINTIES WITH THIS SETUP. IF YOU CAN BELIEVE YOUR EYES...THE EXACT SAME THING LOOKS TO HAPPEN BY LATE MONDAY INTO TUESDAY...AS THE MODELS ADVERTISE ANOTHER CUTOFF UPPER LOW FORMING AND RETROGRADING TOWARD THE MID SOUTH REGION. THIS WILL BRING A REINFORCING SHOT OF AT LEAST SMALL RAIN CHANCES TO END THE PERIOD. INITIALLY...TEMPERATURES WILL BE A LITTLE BELOW SEASONAL AVERAGES DUE TO EASTERLY SURFACE FLOW. BY MONDAY AND TUESDAY...TEMPERATURES WILL BE A BIT WARMER...BUT WILL BE KEPT IN CHECK BY CLOUD COVER ASSOCIATED WITH THE UPPER LOWS. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 96 74 90 67 / 20 20 10 10 CAMDEN AR 97 76 95 72 / 30 30 20 20 HARRISON AR 96 73 90 66 / 20 20 10 10 HOT SPRINGS AR 98 77 95 72 / 30 30 20 10 LITTLE ROCK AR 98 77 95 70 / 30 30 20 10 MONTICELLO AR 96 76 94 72 / 30 30 20 10 MOUNT IDA AR 97 77 94 71 / 30 30 20 10 MOUNTAIN HOME AR 97 72 90 66 / 20 20 10 10 NEWPORT AR 96 74 90 67 / 20 20 10 10 PINE BLUFF AR 97 76 94 70 / 30 30 20 10 RUSSELLVILLE AR 97 76 95 71 / 30 20 20 10 SEARCY AR 97 75 92 68 / 30 20 10 10 STUTTGART AR 97 76 93 69 / 30 30 20 10 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 51
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
217 PM MST WED JUL 10 2013 .SYNOPSIS... A MUCH MORE FAVORABLE SOUTHEASTERLY FLOW WILL CONTINUE TO IMPORT DEEPER MONSOON MOISTURE INTO THE REGION OVER THE NEXT COUPLE DAYS. THIS WILL LEAD TO AN APPRECIABLE INCREASE IN SHOWERS AND THUNDERSTORMS ACROSS THE ENTIRE AREA THAT WILL LAST THROUGH FRIDAY. THE INCREASED MOISTURE WILL ALSO RESULT IN COOLER DAYTIME TEMPERATURES FOR THE REST OF THE WORK WEEK. WARMER TEMPERATURES AND A GENERAL DECREASE IN THUNDERSTORM ACTIVITY CAN BE EXPECTED OVER THE WEEKEND...HOWEVER A RETURN TO AN ACTIVE MONSOON PERIOD IS LIKELY AGAIN EARLY NEXT WEEK. && .DISCUSSION... APPEARS THIS AFTERNOON / EVENING COULD BE SHAPING UP TO BE A LOT MORE ACTIVE CONVECTIVELY THAN IT HAS BEEN THE LAST SEVERAL DAYS. AREA SOUNDINGS FROM THIS MORNING SHOW A TONGUE OF HIGH PWAT HAS WORKED ITS WAY INTO THE CENTRAL DESERTS...ASSISTED BY THE SOUTH TO SOUTHEAST FLOW THAT WAS SET UP BY THE CONVECTIVE COMPLEX OVER MEXICO LAST EVENING. INSTABILITY HAS ALSO INCREASED ACROSS THE REGION...WITH THIS MORNINGS KPSR 12Z SOUNDING SHOWING POSITIVE ENERGY IN EXCESS OF 2200 J/KG. MODEL SOUNDINGS SHOW AVAILABLE CAPE OF 1000 TO OVER 1900 J/KG AVAILABLE FOR STORMS TO TAP INTO. SKIES CLEARED OUT FAIRLY EARLY IN THE WAKE OF THE EARLY MORNING CONVECTION...ENABLING TEMPERATURES TO BEGIN CLIMBING ACROSS EAST CENTRAL ARIZONA. ALL THIS POINTS TO INCREASED CHANCES OF STORMS TODAY. IT WAS NOTED BY OTHER FORECAST STAFF THAT AFTERNOON ACARS SOUNDINGS FOR PHX WERE SHOWING THE EXISTENCE OF A MID-LEVEL CAP. THIS COULD BE A HINDRANCE TO EARLY STORM DEVELOPMENT...BUT IT IS EXPECTED THAT THIS WILL ERODE AND STORMS THAT DUE DEVELOP TO OUR EAST AND SOUTHEAST WILL BE ABLE TO PROPAGATE INTO THE CENTRAL DESERTS. LOCAL WRF4KM...U OF A WRF...NMM6KM...AND HRRR MESOSCALE FORECAST MODELS ALL DEPICT STORMS MOVING FROM THE SOUTHEAST INTO THE CENTRAL DESERTS FROM THE EVENING TO EARLY MORNING HOURS. AHEAD OF ARRIVAL OF THE FIRST STORMS BLOWING DUST WILL BE A BIG CONCERN...ESPECIALLY ALONG THE I-10 CORRIDOR BETWEEN CASA GRANDE AND PHOENIX. SOME CONVECTION WILL LIKELY LINGER INTO THE MORNING HOURS AND THE AXIS OF STORMS IS EXPECTED TO SHIFT MORE WESTWARD INTO WESTERN MARICOPA COUNTY...EASTERN YUMA...AND EASTERN LA PAZ COUNTIES. MODELS SHOW PWAT INCREASING THROUGH THURSDAY...WITH ANOTHER POTENTIALLY ACTIVE DAY THURSDAY AFTERNOON AND EVENING. THIS COULD CHANGE HOWEVER IF THERE IS WIDESPREAD CONVECTION OVERNIGHT AND DEBRIS CLOUDINESS HANGS OVER THE REGION THROUGH THE DAY TOMORROW. ELECTED TO KEEP PRETTY MUCH THE SAME POPS WE HAD GOING IN OUR EARLIER PACKAGE...WITH CHANCE VALUES FOR THE EASTERN HALF OF THE FORECAST AREA. AN UPPER LEVEL TROUGH PUSHING INTO THE PACIFIC NORTHWEST WILL CAUSE THE RIDGE OVER THE DESERT SOUTHWEST TO SHIFT FURTHER TO THE SOUTHEAST. THIS WILL BEGIN TO SET UP A DRIER FLOW PATTERN FOR THE WEEKEND. BOTH THE GFS AND ECMWF SHOW PWAT DECREASING FRIDAY THROUGH SUNDAY. AS SUCH EXPECT A LOWER GRADE MONSOON AND STORMS TO REMAIN MAINLY OVER THE HIGHER TERRAIN TO THE EAST AND SOUTHEAST BOTH SATURDAY AND SUNDAY. MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT DEPICTING A VERY WELL DEFINED INVERTED TROUGH/CIRCULATION CENTER HEADED DIRECTLY TOWARDS ARIZONA EARLY NEXT WEEK. MOISTURE WILL LIKELY SURGE BACK NORTH INTO THE REGION AHEAD OF THIS SYSTEM...WHILE DYNAMIC SUPPORT INCREASES. THIS COULD VERY WELL SIGNAL THE START OF ANOTHER MULTI-DAY ACTIVE PERIOD...AND HAVE STARTED TRENDING DAYTIME TEMPERATURES LOWER AND POPS HIGHER. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... THIS AFTERNOON...WESTERLY WINDS ARE EXPECTED TO INCREASE WITH GUSTS AROUND 20 KTS. THIS EVENING COULD BRING SCATTERED TO POSSIBLY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...POTENTIALLY LASTING INTO THE OVERNIGHT HOURS. SOME THUNDERSTORMS COULD BE STRONG...AND CAN/T RULE OUT THE CHANCE OF STRONG WIND GUSTS AND BLOWING DUST AFFECTING AREA TAF SITES. CONFIDENCE IN TIMING AND EVOLUTION OF THIS EVENT IS SOMEWHAT ON THE LOW SIDE...BUT IT IS LOOKING LIKE THIS WILL BE THE FIRST MAJOR MONSOON DAY FOR THE LOWER DESERTS SO FAR THIS SUMMER. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...BROKEN HIGH CLOUDS FINALLY CLEARING A BIT EARLY THIS AFTERNOON ALONG WITH BREEZY SOUTHERLY WINDS. EXPECTING VERY SLIM STORM/RAIN CHANCES FOR THE TAF PERIOD...HOWEVER BREEZY OUTFLOW WINDS AND ACCOMPANYING DUST MAY MOVE INTO THE REGION STARTING THIS EVENING FROM STORMS OVER ARIZONA AND NORTHERN MEXICO. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SATURDAY THROUGH WEDNESDAY... CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL REMAIN INTO THE EARLY WEEKEND...BUT A DRYING TREND WILL KEEP STORMS MAINLY CONFINED TO THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX SUNDAY AND MONDAY. THE DRYING TREND WILL BRING MINIMUM HUMIDITIES INTO THE TEENS ACROSS THE LOWER DESERTS FOR SUNDAY AND MONDAY. OTHER DAYS WILL GENERALLY SEE AFTERNOON MINIMUM VALUES ONLY DROPPING INTO THE 20-30 PERCENT RANGE. OVERNIGHT RECOVERY SHOULD BE GOOD TO EXCELLENT WITH READINGS CLIMBING ABOVE 40 PERCENT MOST NIGHTS. GUSTY WINDS ARE POSSIBLE EACH DAY...AS OUTFLOW BOUNDARIES PROPAGATE AWAY FROM DEVELOPING SHOWERS AND THUNDERSTORMS. && $$ .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MCLANE/MO AVIATION...CDEWEY FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
125 PM MST WED JUL 10 2013 .UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS. && .SYNOPSIS... A MUCH MORE FAVORABLE SOUTHEASTERLY FLOW WILL CONTINUE TO IMPORT DEEPER MONSOON MOISTURE INTO THE REGION OVER THE NEXT COUPLE DAYS. THIS WILL LEAD TO AN APPRECIABLE INCREASE IN SHOWERS AND THUNDERSTORMS ACROSS THE ENTIRE AREA THAT WILL LAST THROUGH FRIDAY. THE INCREASED MOISTURE WILL ALSO RESULT IN COOLER DAYTIME TEMPERATURES FOR THE REST OF THE WORK WEEK. WARMER TEMPERATURES AND A GENERAL DECREASE IN THUNDERSTORM ACTIVITY CAN BE EXPECTED OVER THE WEEKEND...HOWEVER A RETURN TO AN ACTIVE MONSOON PERIOD IS LIKELY AGAIN EARLY NEXT WEEK. && .DISCUSSION... SO FAR THIS MONSOON SEASON THUNDERSTORMS HAVE STAYED ALONG THE PERIPHERY OF THE WFO PHOENIX FORECAST AREA...WITH ACTIVITY MAINLY CONFINED TO THE MOGOLLON RIM AND EXTREME SOUTHEAST ARIZONA. THIS IS LIKELY TO CHANGE AS EARLY AS TODAY...AS THE AIRMASS HAS MOISTENED...INSTABILITY HAS INCREASED...FLOW HAS BECOME MORE SOUTHEAST AND BETTER DYNAMICS ARE IN-PLACE. DESPITE EARLY MORNING CLOUDINESS FROM CONVECTION SPAWNED BY THE MCS OVER MEXICO...CLEARING SKIES IN THE EASTERN HALF OF THE FORECAST AREA WILL ALLOW TEMPERATURES TO BEGIN CLIMBING...HELPING TO DESTABILIZE THE REGION AND SETTING THE STAGE FOR ADDITIONAL CONVECTION THIS AFTERNOON. THE 12Z KPSR AND KTWC SOUNDINGS SHOWED PWAT OF 1.88 AND 1.86 RESPECTIVELY. FOR KTWC...THIS WAS SIMILAR TO 24-HOURS AGO...BUT FOR KPSR THE VALUE WAS ABOUT 4 TENTHS OF AN INCH INCREASE FROM YESTERDAY. THIS TREND SHOWS DEEPER MOISTURE HAS IN FACT WORKED ITS WAY INTO THE CENTRAL DESERTS. BOTH SOUNDINGS SHOWED SIGNIFICANT CAPE AVAILABLE FOR DEVELOPING STORMS TO TAP. WILL NEED TO WATCH OUTFLOW BOUNDARIES FROM STORMS DEVELOPING TO OUR EAST AND SOUTHEAST. GUSTY WINDS AND BLOWING DUST WILL OBVIOUSLY BE A CONCERN...HOWEVER BOUNDARY COLLISIONS WILL BE MORE LIKELY TO TRIGGER NEW CONVECTION. FORECAST PACKAGE WAS PRETTY MUCH ON TRACK. TEMPERATURES WERE RUNNING A FEW DEGREES COOLER THAN FORECAST DUE TO CLOUDINESS SO MADE SOME MINOR ADJUSTMENTS TO AFTERNOON HIGHS IN SOME LOCATIONS. ALSO LOWERED POPS THIS MORNING FOR SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA ZONES. && .PREV DISCUSSION... ISSUED AT 501 AM MST WED JUL 10 2013 A PARADE OF INVERTED TROUGHS/CIRCULATION CENTERS CONTINUES TO MARCH WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL HIGH CENTERED OVER WEST TEXAS THIS MORNING. THE MOST IMPRESSIVE WAVE NEAR 28N 108W HAS SUPPORTED AN IMPRESSIVE MCS OVER NORTHERN MEXICO FEEDING ON MUCAPES OVER 1000 J/KG AND PWATS EXCEEDING 2.0 INCHES. CLOUDS TOPS HAVE RAPIDLY WARMED IN THE PAST HOUR WITH A NOTABLE RAPID DECREASE IN LIGHTNING ACTIVITY...SIGNALING A DOWNTREND IN CONVECTIVE STRENGTH. NEVERTHELESS...OUTFLOWS...GRAVITY WAVES...AND INFUSION/ADVECTION OF MOISTURE INTO THE MID LEVELS HAS ALLOWED SHOWERS TO DEVELOP OVER PARTS OF CENTRAL AND SOUTHWEST ARIZONA OVERNIGHT. SOME STRONGER WIND GUSTS HAVE ALSO BEEN OBSERVED WITH THIS ACTIVITY BEHIND OUTFLOW BOUNDARIES...AND EXPECTING THIS TREND WILL CONTINUE FOR THE NEXT SEVERAL HOURS BEFORE THE ENTIRE SYSTEM DECAYS. RECENT HRRR OUTPUT HAS BEST CAPTURED RADAR TRENDS...AND HAVE TAILORED SLIGHT CHANCE SHOWER POPS BASED IN ITS OUTPUT THROUGH THE MID MORNING AS ACTIVITY WANES. SEVERAL FACETS OF THE FORECAST SUGGEST LATE THIS AFTERNOON...AND PARTICULARLY THIS EVENING AND OVERNIGHT WILL BECOME QUITE ACTIVE OVER MUCH OF THE FORECAST AREA. FIRST...THE PRESENCE OF THE SONORAN INVERTED TROUGH SHOULD PROVIDE AMPLE DIFLUENCE ALOFT SUPPORTIVE FOR CONVECTIVE SUSTENANCE. SECOND...A TONGUE OF RICH MOISTURE SHOULD BE ADVECTED NORTHWEST THROUGHOUT THE DAY...AS EVIDENCED BY OBJECTIVE ANALYSIS OF +10C H7 DEWPOINTS AND +15C H8 DEWPOINTS LURKING IN SOUTHEAST ARIZONA (TRANSLATING TO DEEP 11-12 G/KG MIXING RATIOS). THERE IS ALSO SLIGHTLY COOLER TEMPERATURES IN THIS LAYER WHICH WILL GRADUALLY ERODE THE CAPPING INVERSION NEAR THE H7 LAYER. FORECAST SOUNDINGS INDICATE INSTABILITY BECOMING MAXIMIZED AOA 750 J/KG DURING PEAK HEATING WITH INHIBITION SLOWLY ERODING. HRRR AND HIGH RESOLUTION WRF NMM CORES (AND TO SOME EXTENT THE COARSER GFS) ARE IN GENERAL AGREEMENT OF A MORE CLASSIC MONSOON PATTERN OF CONVERGENT CONVECTIVE COMPLEXES FROM BOTH THE MOGOLLON RIM AND SERN ARIZONA PROGRESSING THROUGH LOWER ELEVATIONS WESTWARD TO THE COLORADO RIVER VALLEY THROUGHOUT THE EVENING AND OVERNIGHT. ON THE OTHER HAND...ARW CORES AND THE ECMWF ARE NOT AS BULLISH WITH THE MAINTENANCE OF CONVECTION TONIGHT. REGARDLESS...CONCEPTUALLY THE CURRENT PATTERN FAVORS AT LEAST A PARTIALLY ACTIVE DAY...IF NOT VERY ACTIVE...THOUGH ENOUGH UNCERTAINTY EXISTS TO PRECLUDE UNUSUALLY HIGH POPS. ANY STRONGER THUNDERSTORM WILL INITIALLY HAVE THE POSSIBILITY OF PRODUCING SEVERE WIND GUSTS AND DENSE BLOWING DUST AS T/TD SPREADS WILL BE ABOVE 40F...THOUGH AS ACTIVITY EVOLVES OVERNIGHT AND THE ATMOSPHERIC PROFILE BECOME MORE MOIST...THE THREAT SHOULD TRANSITION TO MORE OF A HEAVY RAIN THREAT (THOUGH STRONGER WINDS STILL CANNOT BE DISCOUNTED). LARGE UNCERTAINTY EXISTS REGARDING THE PROCESSION OF TEMPERATURES AND CONVECTIVE THREAT THURSDAY...PRIMARILY DEPENDENT ON THE ANTECEDENT CONDITIONS AND ACTIVITY WEDNESDAY NIGHT. SOME MODEL FORECASTS SUGGEST THURSDAY MAY BE ONE OF THOSE RARE SUMMER DAYS SOCKED IN WITH CLOUDS...UNUSUALLY COOL TEMPERATURES...AND LITTLE AVAILABLE INSTABILITY. HOWEVER...IF CLOUDS BEGIN TO CLEAR DURING PEAK HEATING IT WILL TAKE ONLY A FEW HOURS TO REALIZE MLCAPES ABOVE 1000 J/KG COINCIDENT WITH AMPLE SHEAR AND MOISTURE PROFILES. KEPT POPS GENERALLY IN THE 30 PERCENT CHANCE CATEGORY GIVEN THE OVERALL LOW CONFIDENCE FORECAST...THOUGH IF ORGANIZED CONVECTION DOES FORM IMPACTS COULD BE SIGNIFICANT. REGARDLESS...IT APPEARS TEMPERATURES WILL STAY IN A BELOW NORMAL CATEGORY (WHETHER A FEW DEGREES OR 10+ DEGREES BELOW REMAINS TO BE SEEN). FRIDAY COULD BE A SLOWER CONVECTIVE DAY IF THURSDAY ENDS UP BEING AN ACTIVE MONSOON DAY...OR VICE VERSA COULD BE ACTIVE IF THURSDAY REMAINS CONTAMINATED AND THE POSSIBILITY OF ANOTHER INVERTED TROUGH ROTATING WESTWARD FROM THE GULF OF MEXICO CAN COME TO FRUITION. AMPLE MONSOON MOISTURE WILL STILL BE IN PLACE SUCH THAT AREAWIDE SLIGHT CHANCE TO CHANCE POPS ARE STILL WARRANTED...THOUGH THE TREND WAS TO TEMPER POPS SOMEWHAT. AS THE WEST TEXAS SUBTROPICAL HIGH BEGINS TO STRENGTHEN...EXPAND...AND RETROGRADE WESTWARD...THERE SHOULD BE A GRADUAL DECREASE IN MOISTURE OVER THE WEEKEND NECESSITATING LOWER PRECIPITATION CHANCES IN THE FORECAST. AS THE MOISTURE DECREASES...TEMPERATURES WILL REBOUND WITH HIGHS RETURNING TO ABOVE NORMAL LEVELS. MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT DEPICTING A VERY WELL DEFINED INVERTED TROUGH/CIRCULATION CENTER HEADED DIRECTLY TOWARDS ARIZONA EARLY NEXT WEEK. MOISTURE WILL LIKELY SURGE BACK NORTH INTO THE REGION AHEAD OF THIS SYSTEM...WHILE DYNAMIC SUPPORT INCREASES. THIS COULD VERY WELL SIGNAL THE START OF ANOTHER MULTI-DAY ACTIVE PERIOD...AND HAVE STARTED TRENDING DAYTIME TEMPERATURES LOWER AND POPS HIGHER. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... THIS AFTERNOON...WESTERLY WINDS ARE EXPECTED TO INCREASE WITH GUSTS AROUND 20 KTS. THIS EVENING COULD BRING SCATTERED TO POSSIBLY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...POTENTIALLY LASTING INTO THE OVERNIGHT HOURS. SOME THUNDERSTORMS COULD BE STRONG...AND CAN/T RULE OUT THE CHANCE OF STRONG WIND GUSTS AND BLOWING DUST AFFECTING AREA TAF SITES. CONFIDENCE IN TIMING AND EVOLUTION OF THIS EVENT IS SOMEWHAT ON THE LOW SIDE...BUT IT IS LOOKING LIKE THIS WILL BE THE FIRST MAJOR MONSOON DAY FOR THE LOWER DESERTS SO FAR THIS SUMMER. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...BROKEN HIGH CLOUDS FINALLY CLEARING A BIT EARLY THIS AFTERNOON ALONG WITH BREEZY SOUTHERLY WINDS. EXPECTING VERY SLIM STORM/RAIN CHANCES FOR THE TAF PERIOD...HOWEVER BREEZY OUTFLOW WINDS AND ACCOMPANYING DUST MAY MOVE INTO THE REGION STARTING THIS EVENING FROM STORMS OVER ARIZONA AND NORTHERN MEXICO. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SATURDAY THROUGH WEDNESDAY... CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL REMAIN INTO THE EARLY WEEKEND...BUT A DRYING TREND WILL KEEP STORMS MAINLY CONFINED TO THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX SUNDAY AND MONDAY. THE DRYING TREND WILL BRING MINIMUM HUMIDITIES INTO THE TEENS ACROSS THE LOWER DESERTS FOR SUNDAY AND MONDAY. OTHER DAYS WILL GENERALLY SEE AFTERNOON MINIMUM VALUES ONLY DROPPING INTO THE 20-30 PERCENT RANGE. OVERNIGHT RECOVERY SHOULD BE GOOD TO EXCELLENT WITH READINGS CLIMBING ABOVE 40 PERCENT MOST NIGHTS. GUSTY WINDS ARE POSSIBLE EACH DAY...AS OUTFLOW BOUNDARIES PROPAGATE AWAY FROM DEVELOPING SHOWERS AND THUNDERSTORMS. && $$ .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MCLANE/MO AVIATION...CDEWEY FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
124 AM MST WED JUL 10 2013 .SYNOPSIS...A FAVORABLE SOUTHEASTERLY FLOW REGIME WILL RESULT IN GREATER THUNDERSTORM COVERAGE THROUGH THURSDAY. THUNDERSTORM CHANCES WILL GRADUALLY DECREASE FRIDAY THROUGH SUNDAY. THEREAFTER... THUNDERSTORM COVERAGE WILL INCREASE EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM APPROACHES FROM THE EAST. EXPECT COOLER DAYTIME TEMPERATURES BY THURSDAY FOLLOWED BY A WARMING TREND THIS WEEKEND. && .DISCUSSION...THUNDERSTORM ARE FORMING ACROSS SANTA CRUZ COUNTY AND OVER THE PINALINOS MTNS...WHICH IS ABOUT AN HOUR LATER THAN MODELS PROGGED. CONVECTIVE TEMP IN TUCSON BASED ON THIS MORNINGS SOUNDING IS 95 DEGREES AND WE ARE CURRENTLY HOVERING AT 94. STILL EXPECTING AN ACTIVE DAY THIS AFTERNOON...BUT THE LATEST HRRR DATA HINTS THAT WE HAVE TOO MUCH OF A GOOD THING TODAY. THE ABUNDANT MOISTURE AND JUST ENOUGH HEATING SEEM TO BREAKOUT WIDESPREAD WEAK CONVECTION. FROM THERE...THE HEATING IS MARGINALIZED AND THE WE FAIL TO SEE THE ORGANIZED CONVECTION PREVIOUSLY NOTED IN THE MODELS. BUT THE DAY IS YOUNG AND I AM NOT READY TO WRITE OFF THE ACTIVITY JUST YET. FOR TOMORROW...FORECAST SOUNDINGS SUGGEST SLIGHTLY DRIER MIDLEVELS TOMORROW...BUT PWATS ONLY DIP BY A TENTH OF AN INCH. THE UPPER HIGH WILL SLIDE EAST AND KEEP AZ IN FAVORABLE SOUTHEAST FLOW SO I AM NOT CONFIDENT THIS SLIGHT DECREASE IN MOISTURE WILL ACTUALLY TRANSPIRE. MY MAIN CONCERN FOR CONVECTION TOMORROW WILL BE THE EXTENT OF THE ACTIVITY OVERNIGHT TONIGHT...AND LINGERING MORNING CLOUD COVER TOMORROW. IF THE MCS SITUATION DEVELOPS THEN WE MIGHT BE TOO WORKED OVER TO SEE MID DAY CONVECTION TOMORROW. THE UOFA NAM WRF SEEMS TO FOLLOW THIS THEME AND KEEPS CONVECTION AT BAY UNTIL AFTER 6 PM TOMORROW. THE HIGH CONTINUES A SLOW MIGRATION EASTWARD THROUGH FRIDAY AND WE START TO SEE THE MID LEVEL FLOW WEAKEN. GIVEN THAT TREND...STILL EXPECT SOME CONVECTION FRIDAY AND SATURDAY...BUT INCREASING MID LEVEL DRYING BY SUNDAY SHOULD LIMIT OUR PRECIP CHANCES. A BIG CHANGE WOULD QUICKLY FOLLOW THE POTENTIAL DRYING ON SUNDAY. THE MODELS CONTINUE TO SHOW AN INVERTED TROUGH MOVING INTO SE AZ STARTING MONDAY MORNING. THE LATEST MODEL RUNS HAVE SLOWED THE SYSTEM ONCE IT REACH AZ KEEPING THE SYSTEM INFLUENCING AZ THROUGH FRIDAY. THAT SEEMS A BIT LONG...BUT I DO BUY THE SLOW MOVING SOLUTION DUE TO THE DEVELOPING UPPER TROUGH OVER THE PACIFIC NORTHWEST. OUR INVERTED TROUGH WOULD SIT BETWEEN THE PACIFIC TROUGH AND THE MONSOON RIDGE OVER THE GREAT PLAINS. THESE INVERTED TROUGHS OFTEN BRING WIDESPREAD RAIN TO AZ AND CAN KEEP OVERNIGHT CONVECTION ACTIVE. SO I INCREASED POPS A BIT IN THE EXTENDED ESPECIALLY DURING THE OVERNIGHT HOURS. JJB && .AVIATION...EXPECT ANOTHER ROUND OF THUNDERSTORMS THIS AFTERNOON INTO THE EVENING THROUGH 11/06Z. LCL CIGS BKN020-030 AGL NEAR THE STORMS. SMALL HAIL LIKELY NEAR THE THUNDERSTORM CORE WITH LOCALLY HEAVY RAINFALL. STRONG ERRATIC WIND GUSTS NEAR 50KTS WITH THE STRONGEST THUNDERSTORMS. STORM MOTION FROM THE ESE TOWARDS THE WNW 10-15 KTS. LIGHT WINDS WEST TO NORTHWEST 10-15 KTS BECOMING LIGHT AND VARIABLE AFT 11/04Z. && .FIRE WEATHER...SCATTERED MAINLY LATE AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THIS WEEK. AN UNUSUALLY MOISTURE AIR MASS IS OVER SOUTHERN ARIZONA FOR THIS TIME OF YEAR. THE STRONGER THUNDERSTORMS WILL PRODUCE GUSTY AND ERRATIC WINDS AND LOCALLY HEAVY RAINS. THE STRONGEST THUNDERSTORMS ARE EXPECTED TONIGHT THROUGH TOMORROW. OUTSIDE OF THE THUNDERSTORM ACTIVITY... NORMAL DIURNAL WIND TRENDS ARE EXPECTED TO OCCUR THROUGH THE WEEKEND. DAYTIME RELATIVE HUMIDITIES WILL RANGE FROM THE 20S TO 30S WITH GOOD NIGHTTIME RECOVERIES. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON DISCUSSION...BROST AVIATION/FIRE WEATHER...SAMPSON
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
952 AM MST WED JUL 10 2013 .SYNOPSIS... A MUCH MORE FAVORABLE SOUTHEASTERLY FLOW WILL CONTINUE TO IMPORT DEEPER MONSOON MOISTURE INTO THE REGION OVER THE NEXT COUPLE DAYS. THIS WILL LEAD TO AN APPRECIABLE INCREASE IN SHOWERS AND THUNDERSTORMS ACROSS THE ENTIRE AREA THAT WILL LAST THROUGH FRIDAY. THE INCREASED MOISTURE WILL ALSO RESULT IN COOLER DAYTIME TEMPERATURES FOR THE REST OF THE WORK WEEK. WARMER TEMPERATURES AND A GENERAL DECREASE IN THUNDERSTORM ACTIVITY CAN BE EXPECTED OVER THE WEEKEND...HOWEVER A RETURN TO AN ACTIVE MONSOON PERIOD IS LIKELY AGAIN EARLY NEXT WEEK. && .DISCUSSION... SO FAR THIS MONSOON SEASON THUNDERSTORMS HAVE STAYED ALONG THE PERIPHERY OF THE WFO PHOENIX FORECAST AREA...WITH ACTIVITY MAINLY CONFINED TO THE MOGOLLON RIM AND EXTREME SOUTHEAST ARIZONA. THIS IS LIKELY TO CHANGE AS EARLY AS TODAY...AS THE AIRMASS HAS MOISTENED...INSTABILITY HAS INCREASED...FLOW HAS BECOME MORE SOUTHEAST AND BETTER DYNAMICS ARE IN-PLACE. DESPITE EARLY MORNING CLOUDINESS FROM CONVECTION SPAWNED BY THE MCS OVER MEXICO...CLEARING SKIES IN THE EASTERN HALF OF THE FORECAST AREA WILL ALLOW TEMPERATURES TO BEGIN CLIMBING...HELPING TO DESTABILIZE THE REGION AND SETTING THE STAGE FOR ADDITIONAL CONVECTION THIS AFTERNOON. THE 12Z KPSR AND KTWC SOUNDINGS SHOWED PWAT OF 1.88 AND 1.86 RESPECTIVELY. FOR KTWC...THIS WAS SIMILAR TO 24-HOURS AGO...BUT FOR KPSR THE VALUE WAS ABOUT 4 TENTHS OF AN INCH INCREASE FROM YESTERDAY. THIS TREND SHOWS DEEPER MOISTURE HAS IN FACT WORKED ITS WAY INTO THE CENTRAL DESERTS. BOTH SOUNDINGS SHOWED SIGNIFICANT CAPE AVAILABLE FOR DEVELOPING STORMS TO TAP. WILL NEED TO WATCH OUTFLOW BOUNDARIES FROM STORMS DEVELOPING TO OUR EAST AND SOUTHEAST. GUSTY WINDS AND BLOWING DUST WILL OBVIOUSLY BE A CONCERN...HOWEVER BOUNDARY COLLISIONS WILL BE MORE LIKELY TO TRIGGER NEW CONVECTION. FORECAST PACKAGE WAS PRETTY MUCH ON TRACK. TEMPERATURES WERE RUNNING A FEW DEGREES COOLER THAN FORECAST DUE TO CLOUDINESS SO MADE SOME MINOR ADJUSTMENTS TO AFTERNOON HIGHS IN SOME LOCATIONS. ALSO LOWERED POPS THIS MORNING FOR SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA ZONES. && .PREV DISCUSSION... ISSUED AT 501 AM MST WED JUL 10 2013 A PARADE OF INVERTED TROUGHS/CIRCULATION CENTERS CONTINUES TO MARCH WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL HIGH CENTERED OVER WEST TEXAS THIS MORNING. THE MOST IMPRESSIVE WAVE NEAR 28N 108W HAS SUPPORTED AN IMPRESSIVE MCS OVER NORTHERN MEXICO FEEDING ON MUCAPES OVER 1000 J/KG AND PWATS EXCEEDING 2.0 INCHES. CLOUDS TOPS HAVE RAPIDLY WARMED IN THE PAST HOUR WITH A NOTABLE RAPID DECREASE IN LIGHTNING ACTIVITY...SIGNALING A DOWNTREND IN CONVECTIVE STRENGTH. NEVERTHELESS...OUTFLOWS...GRAVITY WAVES...AND INFUSION/ADVECTION OF MOISTURE INTO THE MID LEVELS HAS ALLOWED SHOWERS TO DEVELOP OVER PARTS OF CENTRAL AND SOUTHWEST ARIZONA OVERNIGHT. SOME STRONGER WIND GUSTS HAVE ALSO BEEN OBSERVED WITH THIS ACTIVITY BEHIND OUTFLOW BOUNDARIES...AND EXPECTING THIS TREND WILL CONTINUE FOR THE NEXT SEVERAL HOURS BEFORE THE ENTIRE SYSTEM DECAYS. RECENT HRRR OUTPUT HAS BEST CAPTURED RADAR TRENDS...AND HAVE TAILORED SLIGHT CHANCE SHOWER POPS BASED IN ITS OUTPUT THROUGH THE MID MORNING AS ACTIVITY WANES. SEVERAL FACETS OF THE FORECAST SUGGEST LATE THIS AFTERNOON...AND PARTICULARLY THIS EVENING AND OVERNIGHT WILL BECOME QUITE ACTIVE OVER MUCH OF THE FORECAST AREA. FIRST...THE PRESENCE OF THE SONORAN INVERTED TROUGH SHOULD PROVIDE AMPLE DIFLUENCE ALOFT SUPPORTIVE FOR CONVECTIVE SUSTENANCE. SECOND...A TONGUE OF RICH MOISTURE SHOULD BE ADVECTED NORTHWEST THROUGHOUT THE DAY...AS EVIDENCED BY OBJECTIVE ANALYSIS OF +10C H7 DEWPOINTS AND +15C H8 DEWPOINTS LURKING IN SOUTHEAST ARIZONA (TRANSLATING TO DEEP 11-12 G/KG MIXING RATIOS). THERE IS ALSO SLIGHTLY COOLER TEMPERATURES IN THIS LAYER WHICH WILL GRADUALLY ERODE THE CAPPING INVERSION NEAR THE H7 LAYER. FORECAST SOUNDINGS INDICATE INSTABILITY BECOMING MAXIMIZED AOA 750 J/KG DURING PEAK HEATING WITH INHIBITION SLOWLY ERODING. HRRR AND HIGH RESOLUTION WRF NMM CORES (AND TO SOME EXTENT THE COARSER GFS) ARE IN GENERAL AGREEMENT OF A MORE CLASSIC MONSOON PATTERN OF CONVERGENT CONVECTIVE COMPLEXES FROM BOTH THE MOGOLLON RIM AND SERN ARIZONA PROGRESSING THROUGH LOWER ELEVATIONS WESTWARD TO THE COLORADO RIVER VALLEY THROUGHOUT THE EVENING AND OVERNIGHT. ON THE OTHER HAND...ARW CORES AND THE ECMWF ARE NOT AS BULLISH WITH THE MAINTENANCE OF CONVECTION TONIGHT. REGARDLESS...CONCEPTUALLY THE CURRENT PATTERN FAVORS AT LEAST A PARTIALLY ACTIVE DAY...IF NOT VERY ACTIVE...THOUGH ENOUGH UNCERTAINTY EXISTS TO PRECLUDE UNUSUALLY HIGH POPS. ANY STRONGER THUNDERSTORM WILL INITIALLY HAVE THE POSSIBILITY OF PRODUCING SEVERE WIND GUSTS AND DENSE BLOWING DUST AS T/TD SPREADS WILL BE ABOVE 40F...THOUGH AS ACTIVITY EVOLVES OVERNIGHT AND THE ATMOSPHERIC PROFILE BECOME MORE MOIST...THE THREAT SHOULD TRANSITION TO MORE OF A HEAVY RAIN THREAT (THOUGH STRONGER WINDS STILL CANNOT BE DISCOUNTED). LARGE UNCERTAINTY EXISTS REGARDING THE PROCESSION OF TEMPERATURES AND CONVECTIVE THREAT THURSDAY...PRIMARILY DEPENDENT ON THE ANTECEDENT CONDITIONS AND ACTIVITY WEDNESDAY NIGHT. SOME MODEL FORECASTS SUGGEST THURSDAY MAY BE ONE OF THOSE RARE SUMMER DAYS SOCKED IN WITH CLOUDS...UNUSUALLY COOL TEMPERATURES...AND LITTLE AVAILABLE INSTABILITY. HOWEVER...IF CLOUDS BEGIN TO CLEAR DURING PEAK HEATING IT WILL TAKE ONLY A FEW HOURS TO REALIZE MLCAPES ABOVE 1000 J/KG COINCIDENT WITH AMPLE SHEAR AND MOISTURE PROFILES. KEPT POPS GENERALLY IN THE 30 PERCENT CHANCE CATEGORY GIVEN THE OVERALL LOW CONFIDENCE FORECAST...THOUGH IF ORGANIZED CONVECTION DOES FORM IMPACTS COULD BE SIGNIFICANT. REGARDLESS...IT APPEARS TEMPERATURES WILL STAY IN A BELOW NORMAL CATEGORY (WHETHER A FEW DEGREES OR 10+ DEGREES BELOW REMAINS TO BE SEEN). FRIDAY COULD BE A SLOWER CONVECTIVE DAY IF THURSDAY ENDS UP BEING AN ACTIVE MONSOON DAY...OR VICE VERSA COULD BE ACTIVE IF THURSDAY REMAINS CONTAMINATED AND THE POSSIBILITY OF ANOTHER INVERTED TROUGH ROTATING WESTWARD FROM THE GULF OF MEXICO CAN COME TO FRUITION. AMPLE MONSOON MOISTURE WILL STILL BE IN PLACE SUCH THAT AREAWIDE SLIGHT CHANCE TO CHANCE POPS ARE STILL WARRANTED...THOUGH THE TREND WAS TO TEMPER POPS SOMEWHAT. AS THE WEST TEXAS SUBTROPICAL HIGH BEGINS TO STRENGTHEN...EXPAND...AND RETROGRADE WESTWARD...THERE SHOULD BE A GRADUAL DECREASE IN MOISTURE OVER THE WEEKEND NECESSITATING LOWER PRECIPITATION CHANCES IN THE FORECAST. AS THE MOISTURE DECREASES...TEMPERATURES WILL REBOUND WITH HIGHS RETURNING TO ABOVE NORMAL LEVELS. MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT DEPICTING A VERY WELL DEFINED INVERTED TROUGH/CIRCULATION CENTER HEADED DIRECTLY TOWARDS ARIZONA EARLY NEXT WEEK. MOISTURE WILL LIKELY SURGE BACK NORTH INTO THE REGION AHEAD OF THIS SYSTEM...WHILE DYNAMIC SUPPORT INCREASES. THIS COULD VERY WELL SIGNAL THE START OF ANOTHER MULTI-DAY ACTIVE PERIOD...AND HAVE STARTED TRENDING DAYTIME TEMPERATURES LOWER AND POPS HIGHER. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... FAIRLY STRONG WESTERLY LOW LEVEL FLOW HAS PERSISTED OVERNIGHT KEEPING DRAINAGE WINDS AT BAY...AND WILL LIKELY CONTINUE TO DO SO FOR THE REST OF THIS MORNING. BY THE LATE AFTERNOON...WESTERLY WINDS ARE EXPECTED TO INCREASE WITH GUSTS AROUND 20 KTS. THIS EVENING COULD BRING SCATTERED TO POSSIBLY WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...POTENTIALLY LASTING INTO THE OVERNIGHT HOURS. SOME THUNDERSTORMS COULD BE STRONG...AND CAN/T RULE OUT THE CHANCE OF STRONG WIND GUSTS AND BLOWING DUST AFFECTING AREA TAF SITES. CONFIDENCE IN TIMING AND EVOLUTION OF THIS EVENT IS SOMEWHAT ON THE LOW SIDE...BUT IT IS LOOKING LIKE THIS WILL BE THE FIRST MAJOR MONSOON DAY FOR THE LOWER DESERTS SO FAR THIS SUMMER. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... BROKEN HIGH CLOUDS WILL PERSIST THROUGH THE MORNING HOURS ALONG WITH CONTINUED BREEZY SOUTHERLY WINDS. EXPECTING VERY SLIM STORM/RAIN CHANCES FOR THE TAF PERIOD...HOWEVER BREEZY OUTFLOW WINDS AND ACCOMPANYING DUST MAY MOVE INTO THE REGION STARTING THIS EVENING FROM STORMS OVER ARIZONA AND NORTHERN MEXICO. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL REMAIN INTO THE EARLY WEEKEND...BUT A DRYING TREND WILL KEEP STORMS MAINLY CONFINED TO THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX SUNDAY AND MONDAY. THE DRYING TREND WILL BRING MINIMUM HUMIDITIES INTO THE TEENS ACROSS THE LOWER DESERTS FOR SUNDAY AND MONDAY. OTHER DAYS WILL GENERALLY SEE AFTERNOON MINIMUM VALUES ONLY DROPPING INTO THE 20-30 PERCENT RANGE. OVERNIGHT RECOVERY SHOULD BE GOOD TO EXCELLENT WITH READINGS CLIMBING ABOVE 40 PERCENT MOST NIGHTS. GUSTY WINDS ARE POSSIBLE EACH DAY...AS OUTFLOW BOUNDARIES PROPAGATE AWAY FROM DEVELOPING SHOWERS AND THUNDERSTORMS. && $$ .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MCLANE/MO AVIATION...KUHLMAN FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
925 AM MST WED JUL 10 2013 .SYNOPSIS...A FAVORABLE SOUTHEASTERLY FLOW REGIME WILL RESULT IN GREATER THUNDERSTORM COVERAGE THROUGH THURSDAY. THUNDERSTORM CHANCES WILL GRADUALLY DECREASE FRIDAY THROUGH SUNDAY. THEREAFTER... THUNDERSTORM COVERAGE WILL INCREASE EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM APPROACHES FROM THE EAST. EXPECT COOLER DAYTIME TEMPERATURES BY THURSDAY FOLLOWED BY A WARMING TREND THIS WEEKEND. && .DISCUSSION...INTERESTING DAY IN STORE FOR SOUTHEAST ARIZONA. VIS SATELLITE AND SURFACE OBS DEPICT MORE CLEARING THIS MORNING THAN YESTERDAY. KTUS IS CURRENTLY RUNNING A DEGREE OR TWO WARMER THAN YESTERDAY SO WE STILL HAVE SOME POTENTIAL TO HIT 100 DEGREES AND BREAK THE ALL TIME RECORD CONSECUTIVE STREAK OF HIGH TEMPS OF 100 DEGREES OR GREATER. THE BIGGER CONCERN FROM THE CLEAR SKIES IS THE IMPROVED HEATING THAT WILL CONTINUE THROUGH MID MORNING AND HOW THIS HEATING WILL INFLUENCE OUR CONVECTIVE POTENTIAL TODAY. MORNING SOUNDING WAS IMPRESSIVE. VERY HIGH PRECIP WATER VALUES NEAR 1.9 INCHES WHICH IS ABOVE THE 99TH PERCENTILE FOR THIS TIME OF YEAR. SFC DEW POINTS ACROSS SE AZ AR IN THE MID 60S WITH THE MOIST AIRMASS EXTENDING NORTH OF KPHX. ABUNDANT CAPE EVIDENT ON THE 12Z SOUNDING WITH THE MEAN LAYER CAPE VALUES ARE RUNNING ABOVE THE 75TH PERCENTILE FOR THIS TIME OF YEAR. DCAPE IS ALSO LOOKING GOOD AND WE HAVE ENOUGH SHEAR IN PLACE TO BE CONCERNED FOR ISOLATED SUPERCELLS TODAY. SO ATMOSPHERIC DATA CERTAINLY POINTS TOWARDS INCREASED ACTIVITY TODAY AND WITH THE CLEAR MORNING SKIES...OTHER THAN A FEW CLOUDS HANGING AROUND COCHISE COUNTY...ANTICIPATE AN EARLIER START THAN YESTERDAY. THAT LEADS ME TO THE HIGH RES MODELS. THE UOFA WRF...OUR LOCAL WRF...AND THE HRRR ALL POINT TOWARD SIMILAR SOLUTIONS. BASED ON THE MODELS...CONVECTION SHOULD BEGIN BY NOON TODAY ALONG THE INTERNATIONAL BORDER NEAR SANTA CRUZ COUNTY...AND THEN BUILD NORTHWEST ACROSS PIMA COUNTY. THE MODELS ARE LESS OPTIMISTIC FOR ACTIVITY ACROSS COCHISE COUNTY...LIKELY DUE TO THE MORNING CLOUD COVER...BUT THINKING THESE AREAS MAY SEE THE ACTIVITY LATER IN THE EVENING ONCE THE CONVECTIVE TEMPS ARE MET. SO...CONCERNS TODAY RUN THE GAMUT. SEVERE STORMS WITH STRONG DOWNDRAFTS AND HAIL AND POSSIBLY A SUPERCELL OR TWO...TRANSITIONING TO AN MCS LATER IN THE AFTERNOON. ALSO...THE HIGH MOISTURE CONTENT COMBINED WITH THE HEAVY RAINFALL WE EXPERIENCED YESTERDAY IN SOME LOCATIONS WOULD CERTAINLY FAVOR FLASH FLOODING. FINALLY...THE STORM MOTIONS TODAY ALSO SUGGEST DUST STORM POTENTIAL. SE AZ IS CURRENTLY UNDER A SLIGHT RISK. JJB && .AVIATION...SCT120 NEAR THE INTERNATIONAL BORDER BECOMING MOSTLY SUNNY BY MID-MORNING. EXPECT ANOTHER ROUND OF THUNDERSTORMS THIS AFTERNOON INTO THE EVENING OR FROM 10/18Z THROUGH 11/06Z. LCL CIGS BKN025-030 AGL NEAR THE STORMS. SMALL HAIL LIKELY NEAR THE THUNDERSTORM CORE WITH LOCALLY HEAVY RAINFALL. STRONG ERRATIC WIND GUSTS NEAR 55KTS WITH THE STRONGEST THUNDERSTORMS. STORM MOTION FROM THE EAST TOWARDS THE WEST 10-15 KTS. OUTSIDE OF THE STORMS EXPECT LIGHT VARIABLE WINDS THIS MORNING THEN BECOMING WEST TO NORTHWEST 10-15 KTS AFT 10/20Z AND BECOMING LIGHT AND VARIABLE AGAIN AFT 11/04Z. && .FIRE WEATHER...SCATTERED MAINLY LATE AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE END OF THE WEEK. THE STRONGER THUNDERSTORMS WILL PRODUCE GUSTY AND ERRATIC WINDS AND THE POTENTIAL FOR LOCALLY HEAVY RAINS WILL CONTINUE INTO THURSDAY. AN UNUSUALLY MOISTURE AIR MASS IS OVER SOUTHERN ARIZONA FOR THIS TIME OF YEAR. AWAY FROM THE THUNDERSTORM ACTIVITY...NORMAL DIURNAL WIND TRENDS ARE EXPECTED TO OCCUR THROUGH THE WEEKEND. DAYTIME RELATIVE HUMIDITIES WILL RANGE FROM THE 20S TO 30S WITH GOOD NIGHTTIME RECOVERIES. && .PREV DISCUSSION...HIGH PRESSURE ALOFT CENTERED NEAR THE FOUR CORNERS REGION EARLY THIS MORNING WILL MOVE EWD INTO THE CENTRAL CONUS PLAINS BY MIDDAY FRI. A DEEPER SELY FLOW REGIME WILL BECOME ESTABLISHED LATER TODAY AND CONTINUE INTO THUR. 10/00Z NAM/GFS/ ECMWF CONTINUED WITH GOOD RUN-TO-RUN CONSISTENCY BY DEPICTING HIGHER POPS TO OCCUR THIS AFTERNOON INTO TONIGHT AND AGAIN THUR. THUS...FORECAST CONFIDENCE IS FAIRLY HIGH THAT AN ACTIVE CONVECTIVE PERIOD WILL OCCUR DURING THE AFOREMENTIONED TIME PERIODS. SIMILAR PRECIP WATER VALUES SHOULD TRANSLATE INTO SIMILAR RAINFALL AMOUNTS THAT WERE RECORDED TUE AFTERNOON AND TUE EVENING. HAVE DEPICTED AREAS OF BLOWING DUST LATE THIS AFTERNOON AND EARLY THIS EVENING MAINLY ALONG THE INTERSTATE 10 CORRIDOR NW OF TUCSON AS TSTMS MOVE NWWD INTO SOUTH CENTRAL PINAL COUNTY. A GRADUAL DECREASE IN SHOWER/TSTM COVERAGE IS FORECAST TO OCCUR FRI-SUN AS THE GFS/ECMWF DEPICT THE BULK OF DEEPER MOISTURE TO SHIFT NW OF THE AREA. HAVE TRENDED POPS DOWNWARD ACCORDINGLY FRI-SUN TO REFLECT THIS SCENARIO. THEREAFTER...SHOWER/TSTM COVERAGE SHOULD INCREASE MARKEDLY MON AS AN INVERTED TROUGH ADVANCES WWD ACROSS CHIHUAHUA. SCATTERED TO PERHAPS NUMEROUS SHOWERS/TSTMS ARE FORECAST MON AFTERNOON AND MON EVENING FROM TUCSON EWD/SWD. ISOLATED TO SCATTERED SHOWERS/TSTMS ARE ON TAP ACROSS WRN PIMA COUNTY AND SOUTH CENTRAL PINAL COUNTY. AMPLE MOISTURE IN COMBINATION WITH THE STATIONARY UPPER LEVEL LOW PRESSURE SYSTEM ACROSS NRN SONORA WILL JUSTIFY SCATTERED MAINLY AFTERNOON/EVENING SHOWERS/TSTMS ACROSS MUCH OF SE AZ TUE. THIS SYSTEM HOLDS THE POTENTIAL TO BRING CONSIDERABLE RAINFALL TO SE AZ MON-TUE. HIGH TEMPS TODAY WILL BE ABOUT 2-3 DEGS F COOLER VERSUS MAX TEMPS ACHIEVED TUE. DAYTIME TEMPS THUR WILL BE ABOUT 2-4 DEGS F COOLER VERSUS TODAY...THEN A WARMING TREND WILL OCCUR FRI-SUN IN RESPONSE TO A SLIGHTLY DRIER ENVIRONMENT. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON DISCUSSION...BROST AVIATION/FIRE WEATHER...SAMPSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1103 AM MDT WED JUL 10 2013 .UPDATE...INGREDIENTS LOOK TO BE COMING TOGETHER FOR AN AFTERNOON OF STRONG STORMS OVER NORTHEAST COLORADO. MOIST EASTERLY FLOW WILL CONTINUE BRINGING LOW LEVEL MOISTURE INTO THE AREA. STRONG SOLAR HEATING WILL WARM THE AIRMASS THROUGH MID-AFTERNOON. A SIGNIFICANT BOUNDARY MAY SET UP ACROSS WASHINGTON...MORGAN AND EASTERN WELD COUNTIES...FROM RAIN THAT FELL OVER THE NEBRASKA PANHANDLE AROUND SUNRISE. AN UPPER LEVEL DISTURBANCE IS EXPECTED TO MOVE OUT OF THE MOUNTAINS DURING THE AFTERNOON WHICH SHOULD HELP ORGANIZE CONVECTIVE ACTIVITY THAT DEVELOPS. MODEL CAPE FORECASTS SHOW 3000+ J/KG ON THE NORTHEAST PLAINS LATER THIS AFTERNOON. WILL BE UPDATING THE ZONES TO INCREASE POPS TO 50 PERCENT ACROSS THE PLAINS THIS AFTERNOON. WILL ALSO MENTION THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WIND. && .AVIATION...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE AFTERNOON HOURS AND IMPACT KDEN AS WELL AS THE ARRIVAL AND DEPARTURE GATES. SEVERE WEATHER WITH LARGE HAIL AND STRONG STRAIGHTLINE WINDS WILL BE POSSIBLE TO THE EAST AND NORTHEAST OF OF DENVER. SOUTHEAST AND EASTERLY WINDS ARE EXPECTED DURING THE EARLY AFTERNOON AHEAD OF INITIAL THUNDERSTORM DEVELOPMENT. LATER IN THE AFTERNOON AND EVENING...WINDS WILL PROBABLY BE OUT OF THE NORTH AND NORTHEAST DUE TO OUTFLOW WINDS FROM STRONG SHOWERS ON THE NORTHEAST COLORADO PLAINS. THUNDERSTORM ACTIVITY COULD REMAIN IN THE KDEN VICINITY THROUGH 7 PM. && .HYDROLOGY...SCATTERED THUNDERSTORMS ARE EXPECTED FROM THE HIGHER TERRAIN EASTWARD. SHOWERS OVER THE MOUNTAINS WILL HAVE FORWARD MOTIONS OF 10-20 MPH...REDUCING THE THREAT OF HEAVY RAINFALL AMOUNTS OVER THE BURN AREAS. ON THE PLAINS...THUNDERSTORMS THAT DEVELOP ON BOUNDARIES MAY BE SLOWER MOVING AND CAPABLE OF PRODUCING RAIN AMOUNTS UP TO ONE INCH IN LESS THAN 45 MINUTES. LOCALIZED FLOODING WILL BE POSSIBLE. && .PREV DISCUSSION... /ISSUED 344 AM MDT WED JUL 10 2013/ SHORT TERM...AN UPPER LEVEL HIGH WILL REMAIN OVER THE SRN ROCKIES WITH MDT WNW FLOW ALOFT ACROSS NRN CO. AT THE SFC LOW PRES WILL BE OVER THE MTNS AS SFC HIGH PRES IS OVER THE CNTRL US. THUS ALLOWS FOR INCREASING SELY LOW LVL FLOW EAST OF THE MTNS BY AFTN INTO TONIGHT. CURRENTLY LOW LVL MOISTURE HAS INCREASED BEHIND WEAK COOL FNT ACROSS MOST OF THE PLAINS AS A WEAK DENVER CYCLONE HAS DEVELOPED. MEANWHILE AN UPPER LEVEL JET IS POSITIONED OVER THE FAR NERN CORNER WHICH HAS BEEN ALLOWING FOR SCT SHOWERS EARLY THIS MORNING. FOR THIS AFTN MOST OF THE SHORT RANGE MODELS SHOW S TO SE LOW LVL FLOW EAST OF THE MTNS WITH NO HINTS OF A DENVER CYCLONE EXCEPT FOR THE WRF WHICH KEEPS IT INTACT. IF THE CYCLONE STAYS INTACT THEN A CONVERGENCE ZONE WILL SET UP ALONG THE FRONT RANGE AND BE A FOCUS FOR TSTM DEVELOPMENT. IF THE CYCLONE IS WIPED OUT THEN CONVECTIVE DEVELOPMENT WILL HAVE TO RELY ON OUTFLOW BOUNDARIES FROM TSTMS OVER THE HIGHER TERRAIN WHICH COULD KEEP BEST CHC OF TSTMS EAST OF THE URBAN CORRIDOR. FOR NOW THERE IS TOO MUCH UNCERTAINTY TO MONKEY AROUND WITH THE CURRENT CHC POPS SO WILL JUST LEAVE AS IS. SFC BASED CAPES BY AFTN DEPENDING ON HOW MUCH MIXING OCCURS LOOK TO BE AROUND 1000-1500 J/KG ALONG THE FRONT RANGE TO NEAR 3000 J/KG OVER THE NERN PLAINS. WITH WNW MID LVL FLOW IN THE 25-30 KT RANGE SHEAR WILL BE FAVORABLE FOR A FEW SVR STORMS ESPECIALLY WHERE THE HIGHER CAPES RESIDE OVER THE PLAINS WITH LARGE HAIL AND STRONG WINDS AND POSSIBLY A TORNADO. AS FOR HIGHS THIS AFTN IF YOU BELIEVE THE HRRR AND RAP READINGS ALONG THE FRONT RANGE WILL BE JUST AS HOT AS YESTERDAY WHILE READINGS OVER THE NERN PLAINS WILL BE MAINLY IN THE UPPER 80S TO AROUND 90. FOR NOW WILL KEEP READINGS IN THE UPPER 80S TO LOWER 90S WITH THE WARMEST VALUES CLOSER TO THE FOOTHILLS. NATURALLY IF THE HRRR AND RAP ARE RIGHT MY HIGHS WILL BE OFF BY AROUND 5 DEGREES OVER THE URBAN CORRIDOR. FOR TONIGHT THE TSTMS OVER THE PLAINS SHOULD GRADUALLY DEVELOP INTO AN MCS AND MOVE ESE OUT OF THE AREA BY AROUND MIDNIGHT. ONCE AGAIN COULD SEE A FEW SVR STORMS OVER THE PLAINS DURING THE EARLY EVENING HOURS. WITH HIGH PRECIPITABLE VALUES SOME AREAS OVER THE PLAINS COULD SEE QUITE A BIT OF RAINFALL. IN THE MTNS AND FOOTHILLS TSTM CHANCES SHOULD MOSTLY END BY 00Z. LONG TERM...BY THURSDAY...MODEL CONSENSUS INDICATES THE 500MB RIDGE AXIS ALIGNED WITH THE SPINE OF THE COLORADO/NEW MEXICO ROCKIES WHICH PLACES NORTHEAST COLORADO UNDER A LIGHT NORTHWESTERLY FLOW ALOFT. THIS FLOW DOES LITTLE TO COOL TEMPERATURES ON THURSDAY. MATTER OF FACT...700 MB TEMPERATURES WARM A FEW DEGS C FOLLOWING THE SLIGHT POST-FRONTAL COOL DOWN ON WEDNESDAY. SHOULD SEE LOW/MID 90S FOR AFTERNOON READINGS ON THE PLAINS...LOW-MID 80S IN THE MTN VALLEYS AND 60S-70S FOR HIGH TEMPS AT HIGHER ELEVATIONS. STRONG SUBSIDENCE INVERSION AT MID-LEVELS AND LOWER PRECIPITABLE WATER VALUES SHOULD SIGNIFICANTLY REDUCE THE CHANCE OF T-STORMS ON THURSDAY... PARTICULARLY EAST OF THE MOUNTAINS. ALTHOUGH MODELS SHOW LOW/MID- LEVEL MOISTURE CREEPING UP ON THE PLAINS LATE IN THE DAY WITH INCREASING SOUTHERLY LOW-LEVEL FLOW. COULD SEE ISOLATED T-STORMS FORMING ALONG THE FRONT RANGE BY LATE AFTERNOON AND/OR EARLY EVENING...THEN DRIFTING NORTHEASTWARD OVER THE NEARBY PLAINS WHERE THEY SHOULD DIE A QUICK DEATH WITH A STRONG CAP IN PLACE. ON FRIDAY...MODELS SHOW THE UPPER RIDGE POSITIONED OVER THE ROCKY MOUNTAIN REGION UNDERGOING A POSITIVE TILT AS IT MIGRATES SLOWLY OVER THE WESTERN GREAT PLAINS. THE TILT RESULTS IN A SHIFT TO SOUTHWEST FLOW ALOFT OVER COLORADO WHICH THEN BEGINS TO ADVECT MOISTURE LADEN SUBTROPICAL AIR UP FROM THE DESERT SOUTHWEST. AT THE CORE OF THE 700-500 MB MOISTURE PLUME ARE 6-8 G/KG SPECIFIC HUMIDITIES...WHICH MODELS SHOW SPREADING NORTHWARD OVER WESTERN COLORADO THROUGH THE DAY. BY LATE ON FRIDAY WITH THE 700-500MB HIGH CENTERED OVER SOUTH-CENTRAL KANSAS/NORTH-CENTRAL OKLAHOMA...THIS PLUME OF MOIST SUBTROPICAL AIR ADVANCES EASTWARD OVER EASTERN COLORADO WHERE IT AIDS IN THUNDERSTORM DEVELOPMENT. BY LATE AFTERNOON...COMPUTED SFC BASED CAPES UP AROUND 1500 J/KG ON THE PLAINS AND MARGINAL SHEAR...MAY SEE ONE OR TWO LATE DAY STORMS BECOME SEVERE...BUT WELL EAST OF THE I-25 URBAN CORRIDOR. THERE/S A GREATER RISK FOR LOCALLY HEAVY RAINFALL FROM SLOW MOVING T-STORMS FORMING ALONG OUTFLOW BOUNDARIES. WILL NEED TO CLOSELY MONITOR RECENT BURN SCARS AS LESS THAN A HALF INCH OF RAIN IN A SHORT PERIOD OF TIME COULD CAUSE HEAVY RUNOFF PROBLEMS. TEMPERATURES ON FRIDAY ABOUT THE SAME AS THOSE ON THURSDAY...BUT PROBABLY OCCURRING EARLIER IN THE DAY BEFORE THE ANTICIPATED CLOUD BUILDUP.SHOWERS/STORMS EXPECTED TO LINGERING INTO THE EVENING HOURS WITH THE AXIS OF THE PLUME BISECTING THE FCST AREA FROM SOUTHWEST-TO-NORTHEAST. STORM INTENSITY SHOULD BE LOW...WHILE THE POTENTIAL FOR LOCALLY HEAVY RAIN WILL STILL EXIST. OVER THE WEEKEND...THE UPPER RIDGE GOES THROUGH SOME CHANGES AS IT SPLITS INTO TWO PIECES...ONE PART MIGRATING ACROSS THE UPPER MIDWEST...WHILE THE OTHER PART GAINING STRENGTH NEAR THE FOUR CORNERS. THIS INITIALLY THINS OUT THE PLUME OF SUBTROPICAL MOISTURE STREAMING OVER COLORADO. HOWEVER BY LATE ON SATURDAY THE MONSOONAL FLOW OF MOIST AIR RESUMES...RESULTING IN ANOTHER ROUND OF SCATTERED SHOWERS/T-STORMS SATURDAY AFTERNOON AND EVENING...SOME POSSIBLY PRODUCING LOCALLY HEAVY RAINFALL. HOWEVER STORM DEVELOPMENT ON SUNDAY APPEARS TO CONCENTRATE MORE OVER THE HIGH COUNTRY WITH LOW LEVELS APPEARING DRIER ON THE PLAINS. TEMPERATURES BOTH DAYS REMAIN NEAR TO SLIGHTLY ABOVE AVERAGE. BY MONDAY...THE CORE OF THE SUBTROPICAL MOISTURE PLUME IS PROGGED TO SHIFT EVEN FARTHER WEST AWAY FROM THE FRONT RANGE WITH THE FLOW ALOFT BECOMING MORE EAST-SOUTHEASTERLY IN DIRECTION WITH THE UPPER HIGH OVER THE FOUR CORNERS FALLING APART. THEREFORE CHANCES FOR PRECIP ON MONDAY APPEAR MUCH LOWER ESPLY EAST OF THE MTNS. MODELS ALSO INDICATE SLIGHTLY COOLER TEMPERATURES ON MONDAY. NOT QUITE SURE WHY...POSSIBLY DUE TO GREAT CLOUD COVER. BY TUESDAY...THE HIGHEST SPECIFIC HUMIDITIES REMAIN WEST OF THE CONTINENTAL DIVIDE AS STEERING WINDS ALOFT TURN MORE SOUTHERLY DURING THE DAY. WILL WILL HELP TO INCREASE TEMPERATURES PARTICULARLY ON THE PLAINS. AVIATION...A WEAK DENVER CYCLONE HAS DEVELOPED OVER DIA EARLY THIS MORNING. AS MENTIONED ABV MOST OF THE SHORT RANGE MODELS WIPE IT OUT BY MIDDAY WITH RATHER STG SSE LOW LVL DEVELOPING. THE WRF IS THE ONLY MODEL WHICH KEEPS THE CYCLONE INTACT THRU THE AFTN WHICH LEADS TO VARYING WIND DIRECTIONS DEPENDING ON WHERE IT RESIDES. FOR NOW WILL KEEP WINDS SSE THRU THE AFTN. LATEST DATA SUGGEST TSTMS COULD DVLP AS EARLY AS 19Z AND THEN MOVE EAST OF THE AIRPORT BY 23Z. ITS ENTIRELY POSSIBLE IF THE DENVER CYCLONE GETS WIPED OUT THAT TSTMS MAY NOT AFFECT THE AIRPORT AT ALL AS THEY FOCUS TO THE EAST AND SOUTH HOWEVER WILL KEEP A PROB GROUP IN THE TAF. IF A STRONGER STORM WERE TO AFFECT THE AIRPORT THEN MAY SEE BRIEF MVFR CONDITIONS IN THE 19Z-23Z TIMEFRAME. BY THIS EVENING IT LOOKS LIKE THE TSTM THREAT WILL REMAIN TO THE EAST OF THE AIRPORT. RIGHT NOW THE MODELS SHOW EITHER A SLY OR SELY COMPONENT FOR WINDS WHICH BECOME MORE SSW AFTER 06Z. HYDROLOGY...SCATTERED THUNDERSTORMS WILL DEVELOP BY EARLY AFTN. POTENTIAL RAINFALL AMOUNTS IN THE BURN AREAS WILL BE IN THE 0.25 TO 0.50 RANGE. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DANKERS LONG TERM....99 AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
345 PM EDT WED JUL 10 2013 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUES TO SHOW AN UPPER LEVEL PATTERN OVER THE CONUS DOMINATED BY A PROGRESSIVE NORTHERN STREAM FLOW ALONG THE U.S/CANADIAN BORDER OVER-TOP AN AN ELONGATED AND BROAD WEST TO EAST ORIENTED RIDGE. OTHER FEATURE OF NOTE REMAINS A WEAKENING TUTT FEATURE/UPPER LOW MIGRATING WESTWARD OVER SOUTH FL/FLORIDA STRAITS. THIS FEATURE LOOKS TO HAVE LIMITED IMPACT ON OUR WEATHER OTHER THAN SOME INCREASE IN COLUMN MOISTURE...AND MAINLY FOR THE SOUTHERN HALF OF OUR AREA. AT THIS POINT...THE THERMAL ANOMALY NORMALLY ASSOCIATED WITH TUTT CELLS THAT CAN ENHANCE INSTABILITY OVER LAND HAS ESSENTIALLY COLLAPSED...AND ANY INFLUENCE IT CAN STILL HAVE WILL BE FELT MAINLY OVER FAR SOUTHERN PORTIONS OF THE PENINSULA. AT THE SURFACE...LOCAL REGION IS EXPERIENCING A WEAK GRADIENT JUST TO THE SOUTH OF A BROAD SURFACE RIDGE AXIS EXTENDING FROM THE NORTH-CENTRAL GULF OF MEXICO TO NORTHERN FLORIDA AND THE GA/SC COAST. && .SHORT TERM (THIS EVENING THROUGH FRIDAY)... THROUGH THIS EVENING... THE WEAK GRADIENT IS ALLOWING FOR THE WEST-COAST SEA-BREEZE TO MIGRATE A BIT FURTHER INLAND THIS AFTERNOON. HOWEVER...THE RESIDUAL LIGHT EASTERLY FLOW IS ONCE AGAIN RESULTING IN A WEST COAST DOMINANT CONVECTIVE PATTERN. HI-RESOLUTION CONVECTIVE ALLOWING MODEL SUITE SEEMS ON TRACK INITIATING FIRST CONVECTION DOWN TOWARD FT. MYERS AND THEN "RIPPLING" NORTHWARD UP THE COAST THROUGH THE LATE AFTERNOON AND EARLY EVENING. POP FORECAST WILL CONTINUE TO FOLLOW THIS TREND WITH HIGHEST RAIN CHANCES THROUGH MID AFTERNOON OVER THE SOUTHERN ZONES...AND THEN INCREASING LATE AFTERNOON/EARLY EVENING FURTHER NORTH TOWARD TAMPA BAY AND THE NATURE COAST. TONIGHT... EVENING STORMS DISSIPATE BY 02-03Z OR TRANSLATE OFFSHORE WITH TIME. WEAK LEFTOVER VORTICITY LOBE FROM THE DECAYING TUTT IS FORECAST TO RESIDE ALONG THE FLORIDA WEST COAST LATE TONIGHT INTO THURSDAY MORNING. THIS WEAK CYCLONIC FLOW...AND ANY ASSOCIATED WEAK SURFACE REFECTION/TROUGH FEATURE WOULD LIKELY ENHANCE THE NOCTURNAL STORM POTENTIAL OVER THE COASTAL WATERS AFTER MIDNIGHT. MID-LEVEL FLOW IS ALSO PROGGED BY LATEST NUMERICAL GUIDANCE TO COME AROUND TO A MORE SOUTHERLY DIRECTION EARLY THURSDAY MORNING. THIS STEERING FLOW (IF DEVELOPING QUICKLY ENOUGH) SHOULD RESULT IN SOME OF THIS NOCTURNAL MARINE CONVECTION MIGRATING BACK TOWARD THE IMMEDIATE COAST AROUND DAWN AND INTO AT LEAST THE FIRST FEW DAYLIGHT HOURS. ONCE AGAIN CONVECTION ALLOWING GUIDANCE AND PARAMETRIZED GUIDANCE ALIKE ARE ALL SHOWING THIS POTENTIAL FOR COASTAL SHOWERS/STORM TOMORROW MORNING. THURSDAY... SUBTROPICAL RIDGE AXIS WILL EXTEND ACROSS THE CENTRAL FL PENINSULA...OR EVEN SOUTH-CENTRAL PENINSULA. EXPECTING TO CONTINUE SEEING A SCATTERING OF SHOWERS NEAR THE COAST EARLY IN THE MORNING...WITH THE ACTIVITY BECOME MORE ROBUST BY MIDDAY AS THE SEA-BREEZE BECOMES ESTABLISHED. PLENTY OF DEEP LAYER MOISTURE WILL BE IN PLACE MAKING FOR A FAVORABLE CONVECTIVE ENVIRONMENT. LIGHT FLOW PATTERN NEAR THE RIDGE AXIS TO THE SOUTH OF I-4 WILL KEEP THE SEA-BREEZE FROM MOVING INLAND ALL THAT FAST AND SHOULD SEE A FAIRLY UNIFORM DISTRIBUTION OF CONVECTIVE COVERAGE DURING THE AFTERNOON ACROSS THE SOUTHERN HALF OF THE PENINSULA. FURTHER NORTH ALONG THE NATURE COAST...SYNOPTIC FLOW SHOULD AID THE INLAND PENETRATION OF THIS BOUNDARY AND DECREASE RAIN CHANCES NEAR THE COAST AS WE HEAD THROUGH THE AFTERNOON. THE TAMPA BAY AREA WILL BE THE TRANSITION ZONES...BUT WOULD NOT BE SURPRISED TO SEE THE CONVECTION MOVE INLAND AWAY FROM THE PINELLAS COAST DURING THE AFTERNOON AS WELL. THURSDAY NIGHT SEES THE INLAND STORMS SLOWLY DISSIPATE AFTER SUNSET WITH A GENERALLY DRY SECOND HALF OF THE NIGHT. A SIGNIFICANT AMPLIFICATION TO THE UPPER LEVEL PATTERN WILL BE OCCURRING OVER THE EASTERN CONUS THURSDAY AND THURSDAY NIGHT FOR THE MIDDLE OF JULY AND THIS AMPLIFICATION WILL SEND A SURFACE FRONT TOWARD THE I-10 CORRIDOR. ALL GUIDANCE SHOWS THIS FRONT STALLING NORTH OF OUR AREA...HOWEVER IT MAY BE JUST CLOSE ENOUGH TO ENHANCE THE SHOWER ACTIVITY UP TOWARD LEVY/CITRUS COUNTIES BY LATE THURSDAY NIGHT. FRIDAY IS THE DAY THAT THE CURRENT FORECAST HAS TROPICAL STORM CHANTAL MOVING NEAR THE SOUTHEAST FL COAST AS A DEPRESSION. THERE IS SOME CHANCE THAT CHANTAL WILL NOT EVEN SURVIVE AS A DEPRESSION THIS LONG AND BE NO MORE THAN AN OPEN WAVE OR MID-LEVEL IMPULSE AS IT MOVES NORTHWARD FROM THE CARIBBEAN. WE WILL BE WATCHING CLOSELY IN CASE CHANTAL HOLDS TOGETHER LONGER...HOWEVER AT THIS TIME...THE IMPACTS LOOK TO BE LITTLE MORE THAN SOME INCREASED MOISTURE AND VORTICITY TO INDUCE AN ACTIVE AFTERNOON/EVENING OF STORMS. WILL HAVE THE BEST RAIN CHANCES ALONG AND INLAND FROM THE I-75 CORRIDOR BY THE TIME WE GET TO MID AFTERNOON AS THE LIGHT GRADIENT ALLOWS THE SEA-BREEZE TO SLOWLY PROGRESS INLAND FROM THE BEACHES. && .LONG TERM (SATURDAY THROUGH WEDNESDAY)... THE START OF THE LONG TERM IS HIGHLY LINKED TO THE PROGRESS OF TROPICAL STORM CHANTAL. WITH THE STORM/S CURRENT DISORGANIZED STATUS...GUIDANCE IS WIDELY RANGING. RECENT MODEL TRENDS HAVE BEEN TO BRING THE SYSTEM FURTHER WEST THAN EARLIER RUNS. IF THIS SYSTEM IS ABLE TO SURVIVE...GUIDANCE SUGGESTS IT MAY ENTER A MORE FAVORABLE ENVIRONMENT IN THE NORTHERN CARIBBEAN AND FLORIDA STRAITS IF IT NEARS FLORIDA. THIS SYSTEM IS A BIT OF A FORECAST MYSTERY AS ITS SURVIVAL IS NOT LOOKING LIKELY. THE 00Z CMC IS THE MOST OPTIMISTIC MODEL FOR THE STORM NEARING OUR AREA AND STRENGTHENING IN THE PROCESS...THIS APPEARS UNLIKELY. ON THE OTHER END OF THE SPECTRUM...THE 12Z ECMWF DOES NOT REALLY HAVE CHANTAL AS AN ORGANIZED SYSTEM EVEN AS IT GOES EAST OF FLORIDA. DECIDED TO USE A MIDDLE-OF-THE-ROAD FORECAST PHILOSOPHY WITH THE EXTENDED USING THE GFS AND GRIDDED MOS AS THE FOUNDATION. PAST THE INITIAL CHALLENGE FROM THE TROPICS...A HIGH BUILDS IN OVER THE EASTERN UNITED STATES. THIS PATTERN WILL ALLOW A RETURN TO EASTERLY FLOW AND THE SUMMER THUNDERSTORM PATTERN ALL TOO FAMILIAR TO WEST CENTRAL AND SOUTHWEST FLORIDA THIS SUMMER. && .AVIATION... BKN VFR CIGS WITH TSRA AT OR NEAR THE TERMINALS RESULTING IN LCL MVFR VSBY/CIGS THROUGH SUNSET. WINDS ONSHORE OR BECOMING ONSHORE ALONG THE COAST THIS AFTERNOON...VARIABLE OVERNIGHT...SE TO S THU MORNING. && .MARINE... A WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE EASTERN GULF OF MEXICO THROUGH THURSDAY NIGHT WITH A RIDGE AXIS IN THE VICINITY. CONTINUING TO WATCH TROPICAL STORM CHANTAL IN THE CENTRAL CARIBBEAN...HOWEVER IT NOW APPEARS THAT THIS SYSTEM WILL HAVE LITTLE IMPACT ON THE WIND OR WAVE FORECASTS FOR THE EASTERN GULF OF MEXICO THROUGH THE END OF THE WEEK. && .FIRE WEATHER... A TYPICAL SUMMER TYPE PATTERN WILL EXIST THE NEXT SEVERAL DAYS DOMINATED BY MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS. NO SIGNIFICANT FIRE WEATHER CONCERNS ARE EXPECTED AS RELATIVE HUMIDITY VALUES REMAIN WELL ABOVE CRITICAL LEVELS. NO SIGNIFICANT IMPACTS (IF ANY) ARE ANTICIPATED DURING THE FORECAST PERIOD FROM WHAT IS NOW TROPICAL STORM CHANTAL IN THE CENTRAL CARIBBEAN. && .PRELIMINARY POINT TEMPS/POPS... TPA 77 89 77 89 / 50 40 20 40 FMY 74 91 74 91 / 30 50 20 60 GIF 73 92 73 92 / 20 50 30 60 SRQ 76 89 76 89 / 50 40 20 30 BKV 72 91 71 91 / 50 50 20 50 SPG 78 89 77 89 / 50 40 20 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM...GARCIA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
340 PM EDT WED JUL 10 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL REMAIN OFFSHORE AS A WEAKENING COLD FRONT APPROACHES THE REGION FROM THE NORTHWEST THROUGH LATE WEEK. THIS FRONT IS EXPECTED TO STALL OVER OR CLOSE TO THE AREA THIS WEEKEND AS TROPICAL CYCLONE CHANTAL...OR ITS REMNANTS...APPROACHES THE SOUTHEAST COAST. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... A WEAK LEE TROUGH AND DEEP MOISTURE PERSIST ACROSS OUR INLAND AREAS THIS AFTERNOON. RUC ANALYSIS SHOWS PW VALUES ABOVE 2.2 INCHES INLAND WHILE A POCKET OF SOME DRIER 1.8 PW AIR HAS SHIFTED ONSHORE BEHIND THE SEABREEZE. SFC DEWPOINTS HAVE FLIRTED WITH THE 70 DEGREE MARK AT COASTAL SITES THIS AFTERNOON. EARLIER CONVECTION ACROSS INLAND SOUTHEAST GA WORKED OVER THE ATMOSPHERE IN THOSE AREAS AND SINCE THEN WE HAVE SEEN A MARKED DECREASE IN COVERAGE AND INTENSITY. OUTFLOW BOUNDARIES AND OTHER MESOSCALE INFLUENCES ARE RESPONSIBLE FOR ISOLATED TO SCATTERED CONVECTION MAINLY ACROSS INLAND AREAS. WITH THE LOSS OF DAYTIME HEATING WE SHOULD SEE THIS ACTIVITY FURTHER DIMINISH WITH DRY CONDITIONS OVERNIGHT. LOWS WILL DROP INTO THE LOWER 70S. OVER THE COASTAL WATERS...SHOWERS AND TSTMS WILL INCREASE LATE TONIGHT ESPECIALLY OUTER PORTIONS NEAR THE GULF STREAM. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... THURSDAY AND FRIDAY...HEIGHTS ALOFT WILL BEGIN TO LOWER AS A DEEP TROUGH OF LOW PRESSURE APPROACHES THE EASTERN SEABOARD...NUDGING THE UPPER RIDGE FURTHER INTO THE WESTERN ATLANTIC. ALTHOUGH THE ASSOCIATED COLD FRONT IS EXPECTED TO REMAIN WELL INLAND FROM THE FORECAST AREA THROUGH FRIDAY...A CONTINUOUS STREAM OF MOISTURE FROM BOTH THE GULF AND ATLANTIC WILL CONTINUE TO STREAM ABUNDANT MOISTURE ACROSS THE SOUTHEAST. MODEL SOUNDINGS CAPTURE THIS INCREASING MOISTURE BY SHOWING PWATS STEADILY CLIMBING TO 2.25 INCHES BY FRIDAY MORNING. IN REGARDS TO CONVECTION INITIATION ON THURSDAY...EXPECT DECENT COVERAGE OF SHOWERS AND THUNDERSTORMS BY LATE THURSDAY MORNING ACROSS WESTERN PORTIONS OF THE CWA. HOWEVER...SLIGHTLY LOWER PWATS ALONG THE COASTAL AREA COULD DELAY CONVECTION INITIATION FOR AREAS WEST OF INTERSTATE 95. HOWEVER...STILL EXPECT AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP BY LATE AFTERNOON AS OUTFLOW BOUNDARIES INTERACT WITH THE SEA BREEZE. THIS TREND WILL CONTINUE INTO FRIDAY AS THE TROUGH AND ITS ASSOCIATED COLD FRONT NEARS TO FORECAST AREA...ONLY INCREASING MOISTURE PROFILES. SEVERE POTENTIAL REMAINS QUITE LIMITED...BUT HEAVY RAINFALL AND THE SATURATED GROUND COULD LEAD TO LOCALIZED FLOODING. ON SATURDAY...ANOTHER DAY OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS IS EXPECTED AS THE COLD FRONT NEARS AND POSSIBLE STALLS OVER THE FORECAST AREA. WITH THE POSSIBILITY OF ADDITIONAL MOISTURE STREAMING ONSHORE FROM TROPICAL CYCLONE CHANTAL...PWATS WILL REMAIN AROUND 2 INCHES. THE MAIN THREAT REMAINS HEAVY RAINFALL AND LOCALIZED FLOODING. IN REGARDS TO TEMPERATURES...EXPECT THURSDAY TO THE BE WARMEST DAY...WITH TEMPERATURES JUST SHY OF SEASONAL NORMALS...AROUND 90 DEGREES INLAND AND MID 80S ALONG THE COAST. DECENT CLOUD COVERAGE WILL ONCE AGAIN IMPACT AFTERNOON TEMPERATURES ON FRIDAY AND SATURDAY...WITH MOST AREAS REMAINING IN THE MID TO UPPER 80S. OVERNIGHT LOWS WILL DIP INTO THE LOWER 70S INLAND AND MID TO UPPER 70S ALONG THE COAST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MAIN FORECAST CHALLENGE FOR THE FIRST PART OF THIS THIS PERIOD IS WHAT HAPPENS TO TROPICAL STORM CHANTAL. MODEL TRENDS AS OF LATE HAVE BEEN WEAKER AND MORE DISORGANIZED WITH THE SYSTEM. IF THIS TREND CONTINUES...THEN THE MAIN IMPACTS MAY BE TO EXTEND THE HEAVY RAIN THREAT INTO SUNDAY AND PERHAPS SUNDAY NIGHT. PLEASE REFER TO THE LATEST FORECAST FROM THE NATIONAL HURRICANE CENTER. LOOKS LIKE A RETURN TO MORE TYPICAL SUMMERTIME WEATHER WILL COMMENCE STARTING ON MONDAY AND PERSIST INTO AT LEAST WEDNESDAY...WITH HIGHS MAINLY NEAR 90 AND SCATTERED MAINLY AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS AND KSAV THROUGH 18Z THURSDAY. ISOLATED CONVECTION IS POSSIBLE THIS AFTERNOON AND THU AFTERNOON BUT MAINLY INLAND FROM THE TERMINALS SO WE AVOIDED ANY MENTION OF THUNDER IN THE 18Z TAFS. EXTENDED AVIATION OUTLOOK...LOW PROBABILITIES OF FOG/STRATUS AROUND SUNRISE EACH MORNING. AT LEAST MODERATE CHANCES FOR DIRECT IMPACTS FROM MAINLY AFTERNOON/EVENING SHOWERS/THUNDERSTORMS THURSDAY THROUGH SATURDAY EVENING. LOW CHANCES FOR DIRECT IMPACTS FROM MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ON SUNDAY AND MONDAY. && .MARINE... ATLANTIC HIGH PRESSURE WILL MAINTAIN A SOUTHERLY COMPONENT OVER THE WATERS THROUGH TONIGHT WITH SPEEDS LESS THAN 15 KT. THURSDAY THROUGH MONDAY...BERMUDA HIGH PRESSURE WILL PREVAIL THROUGH LATE WEEK PRIOR TO AN APPROACHING COLD FRONT THE WEST. IN ADDITION...TROPICAL CYCLONE CHANTAL...OR WHAT REMAINS OF CHANTAL...WILL APPROACH THE GA/SC COASTAL WATERS THIS WEEKEND. THE PRESSURE GRADIENT BETWEEN THESE SYSTEMS WILL RESULT IN AT LEAST SOME INCREASE IN WINDS AND SEAS LATE WEEK AND INTO THE WEEKEND. DUE TO SOME UNCERTAINTY IN REGARD TO TROPICAL CYCLONE CHANTAL...WE HAVE CAPPED WINDS AT 18 KT AND SEAS AT 8 FEET. HENCE IT DOES APPEAR QUITE LIKELY THAT SMALL CRAFT ADVISORY CONDITIONS FOR SEAS WOULD BE NEEDED FOR AT LEAST SOME OF OUR MARINE ZONES...MAINLY SATURDAY AND SATURDAY NIGHT. MARINERS ARE URGED TO PAY CLOSE ATTENTION TO THE LATEST FORECASTS. && .HYDROLOGY... AN APPROACHING COLD FRONT IS EXPECTED TO WEAKEN AND STALL OUT OVER THE AREA FRIDAY INTO SATURDAY. AHEAD OF THE FRONT DEEP TROPICAL MOISTURE WILL BE MOVING INTO THE AREA. SLOW STORM MOTIONS AND TRAINING OF STORMS WILL MEAN THE POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED FLOODING THURSDAY THROUGH SATURDAY NIGHT...POSSIBLY LASTING INTO SUNDAY EVENING DEPENDING ON THE THE TRACK OF TROPICAL CYCLONE CHANTAL. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...JRL SHORT TERM...JHP LONG TERM...MTE AVIATION...JRL MARINE...JHP/JRL HYDROLOGY...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
248 PM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * NORTHEAST WINDS EXPECTED AT MDW...BUT LAKE BREEZE BOUNDARY HAS STALLED EAST OF ORD WITH NORTH-NORTHWEST WINDS CONTINUING THERE. KJB //DISCUSSION...UPDATED 20Z... IT APPEARS THAT THE LAKE BREEZE BOUNDARY MAY STRUGGLE TO GET THROUGH ORD THIS AFTERNOON. RADAR TRENDS INDICATE IT TO BE STALLED AROUND 2 TO 3 MILES EAST OF THE TERMINAL. THERE IS STILL A LOW CHANCE OF IT MAKING A SURGE WESTWARD. HOWEVER...IT APPEARS THAT THE GUSTY NORTHWEST WINDS WEST OF THE BOUNDARY HAVE HALTED ITS WESTWARD PROGRESS. THE NEW TAF UPDATE HAS PULLED THE MENTION OF A WIND SHIFT AT ORD. //DISCUSSION...UPDATED 18Z... THE WEATHER PATTERN IS QUIETING DOWN ACROSS THE REGION AS A COLD FRONT CONTINUES TO SHIFT SOUTH ACROSS ILLINOIS AND INDIANA EARLY THIS AFTERNOON. ASIDE FROM SOME SCT TO OCCASIONALLY BKN CIGS AROUND 4000 FEET...SKIES SHOULD REMAIN FAIRLY CLEAR...ESPECIALLY TONIGHT. THE WINDS WILL BE THE MAIN ISSUE THIS AFTERNOON. LOCAL RADAR DATA...ALONG WITH AREA SURFACE OBSERVATIONS INDICATE THAT THE LAKE BREEZE BOUNDARY REMAINS DRAPED FROM NORTH TO SOUTH ACROSS EASTERN COOK COUNTY ABOUT 5 TO 10 MILES EAST OF THE TERMINALS. THE BOUNDARY DOES APPEAR TO BE MOVING SLOWLY WESTWARD...AND IT STILL APPEARS THAT A WIND SHIFT MAY OCCUR AT THE TERMINALS OVER THE NEXT 1 TO 2 HOURS. KJB //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM CONFIDENCE WITH THE LAKE BREEZE BOUNDARY REMAINING EAST OF ORD. KJB //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. TUESDAY...VFR. RODRIGUEZ && .MARINE... 240 PM CDT HIGH PRESSURE OVER THE CENTRAL AND NORTHERN PLAINS WILL BE SPREADING EASTWARD ACROSS LAKE MICHIGAN THURSDAY AND BE OVERHEAD OF THE LAKE BY FRIDAY. THIS WILL KEEP RATHER LIGHT NORTHERLY WINDS ACROSS THE LAKE TONIGHT AND EARLY THURSDAY BUT THE FLOW WILL LIKELY BE LIGHT ENOUGH TO ONSHORE FLOW TO DEVELOP AROUND THE LAKE THURSDAY AFTERNOON. A SIMILAR SET UP MAY OCCUR FRIDAY WITH THE HIGH OVERHEAD. THE MAIN LOW PRESSURE TRACK WILL BE ACROSS SOUTHERN CANADA AND A TROUGH DOES MOVE ACROSS THE CANADIAN PRAIRIES FRIDAY WHICH WILL HELP PUSH THE HIGH EASTWARD AND TIGHTEN UP THE PRESSURE GRADIENT SOMEWHAT ACROSS THE NORTHERN PART OF THE LAKE GOING INTO SATURDAY. WITH THE HIGH TO THE EAST A STEADIER SOUTH TO SOUTHWEST DIRECTION WILL DEVELOP BUT ONSHORE FLOW/LAKE BREEZE DOES LOOK TO DEVELOP ACROSS THE SOUTHERN SHORELINES AGAIN SATURDAY. SOUTHERLY FLOW WILL CONTINUE OVER THE WEEKEND WITH THE BEST PRESSURE GRADIENT ACROSS THE NORTH. A FRONTAL BOUNDARY WILL APPROACH THE U.P. OF MICHIGAN BY SUNDAY AND MAY LEAD TO INCREASED THUNDERSTORM POTENTIAL SUNDAY THROUGH MONDAY AS IT SAGS SOUTHWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1255 PM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * VARIABLE WINDS BETWEEN APPROX 300 AND 350 THROUGH EARLY AFTERNOON WITH SPORADIC GUSTS TO THE MID TEENS. * STEADIER NORTHEAST WIND EXPECTED WITH LAKE PUSH IN THE NEXT 1 TO 2 HOURS. MDB/KJB //DISCUSSION...UPDATED 18Z... THE WEATHER PATTERN IS QUIETING DOWN ACROSS THE REGION AS A COLD FRONT CONTINUES TO SHIFT SOUTH ACROSS ILLINOIS AND INDIANA EARLY THIS AFTERNOON. ASIDE FROM SOME SCT TO OCCASIONALLY BKN CIGS AROUND 4000 FEET...SKIES SHOULD REMAIN FAIRLY CLEAR...ESPECIALLY TONIGHT. THE WINDS WILL BE THE MAIN ISSUE THIS AFTERNOON. LOCAL RADAR DATA...ALONG WITH AREA SURFACE OBSERVATIONS INDICATE THAT THE LAKE BREEZE BOUNDARY REMAINS DRAPED FROM NORTH TO SOUTH ACROSS EASTERN COOK COUNTY ABOUT 5 TO 10 MILES EAST OF THE TERMINALS. THE BOUNDARY DOES APPEAR TO BE MOVING SLOWLY WESTWARD...AND IT STILL APPEARS THAT A WIND SHIFT MAY OCCUR AT THE TERMINALS OVER THE NEXT 1 TO 2 HOURS. KJB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM CONFIDENCE IN A STEADIER NORTHEAST WIND DEVELOPING AFTER 19 UTC. KJB //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. TUESDAY...VFR. RODRIGUEZ && .MARINE... 416 AM CDT AS A TROUGH OF LOW PRESSURE AND ASSOCIATED COLD FRONT BEGIN TO PUSH EAST ACROSS THE NORTHERN PORTIONS OF THE LAKE THIS MORNING...A FAIRLY TIGHT PRESSURE GRADIENT HAS HELPED SOUTHWEST WINDS TO INCREASE TO 15 TO 25 KT OVER THE NORTHERN PORTIONS OF THE LAKE WHILE AREAS FURTHER SOUTH ARE OBSERVING SPEEDS OF 10 TO 20 KT. AS THIS TROUGH/FRONT CONTINUE SOUTHEAST DOWN THE LAKE THIS MORNING...EXPECT THESE SOUTHWEST WINDS TO SHIFT TO THE WEST/NORTHWEST AND THEN HOLD ONTO A NORTHWEST DIRECTION FOR THE REMAINDER OF THE DAY INTO TONIGHT. EXPECT LIGHT NORTHERLY FLOW OVER THE LAKE FOR MOST OF THURSDAY AS HIGH PRESSURE SLOWLY SHIFTS EAST TOWARDS THE CENTRAL GREAT LAKES. BY FRIDAY WINDS TURN BACK TO A SOUTHERLY DIRECTION...AS THIS HIGH SETTLES OVER THE EASTERN GREAT LAKES INTO THE WEEKEND. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1124 AM CDT WED JUL 10 2013 .DISCUSSION... 305 AM CDT FORECAST CHALLENGES THIS WEDNESDAY MORNING INCLUDE STILL AWAITING THE ARRIVAL OF CONVECTION. JOKING ASIDE...IT IS IMPRESSIVE TO GET THROUGH THIS VERY HIGH PWAT AND UNSTABLE AIR ALOFT /MUCAPES 2000-3500 J/KG/ WITHOUT CONVECTION FROM MIDDAY YESTERDAY THROUGH LAST NIGHT. IT REMINDED HOW IMPORTANT THE TIMING OF A TRIGGER OR SOME FORM OF FOCI ARE FOR CONVECTION...OR INHIBITING DEVELOPMENT IF IN THE WAKE OF SUCH FEATURES. BUT BACK TO THE CHALLENGES GOING FORWARD...THERE IS A CHANCE FOR CONVECTION THIS MORNING SOUTH OF I-80 AS THE SURFACE TROUGH /A FOCUS!/ TAPS THE LAST OF THE MOIST AND UNSTABLE AIR. THEN ATTENTION TURNS TO HOW QUICKLY TEMPERATURES WILL WARM AFTER THE SEASONAL AIR ON THU AND FRI. THIS MORNING...WELL-DEFINED UPPER TROUGH ACROSS WESTERN ONTARIO TO NORTHERN IA IS PROGRESSING ESE. THE SURFACE TROUGH EXTENDS FROM A 1000MB LOW IN EASTERN ONTARIO TO THE QUAD CITIES AT 3 AM THIS MORNING. DEW POINTS IN THE MID 70S ARE POOLED ACROSS THE AREA OFFERING A MUGGY START TO THE DAY. SCATTERED ACCAS IS SEEN ON IR IN THE REGION BUT NO SIGNS ON RADAR OR SATELLITE OF THIS DEVELOPING. A SHORT WAVE IMPULSE SEEN ON WATER VAPOR AND 700MB PROFILER ANALYSIS IS TRAVERSING SOUTHERN IA/NORTHERN MO...BASICALLY ALONG THE BASE OF THE PRIMARY TROUGH. WHILE CONVECTIVE ALLOWING GUIDANCE SUCH AS THE HRRR DOES HAVE CONVECTIVE DEVELOPMENT TRAVERSING THE FAR SOUTHERN FORECAST AREA WITH THIS AND ALONG THE SURFACE BOUNDARY DURING MID-MORNING...RADAR TRENDS SHOW SUBTLE ECHOES FURTHER SOUTH. THE LOW-LEVEL JET HAS VEERED AND THE MORE SUBSTANTIAL MOISTURE TRANSPORT HAS ALSO ENDED EARLY THIS MORNING...SO NOT SEEING TOO MUCH HAPPENING. SO ONLY MAINTAINED LOW T-STORM CHANCES IN THE SOUTHERN FORECAST AREA. THIS AFTERNOON INTO TONIGHT...SUBSTANTIAL COLUMN DRYING IS FORECAST AS THE AFTERNOON PROGRESSES. SURFACE DEW POINTS WILL FALL SLOWLY THROUGH THE 60S AND WILL LIKELY STILL SUPPORT AT LEAST FEW AND POTENTIALLY SCATTERED CU. THE 850MB TEMPERATURES IN THE MID-UPPER TEENS FORECAST AT 18Z ACROSS THE FORECAST AREA...ALONG WITH THE WARM STARTING POINT FOR TEMPERATURES...INDICATE MANY COMMUNITIES REACHING THE MID AND POTENTIALLY UPPER 80S. AREAS NEAR THE WI STATE LINE ARE MORE LIKELY TO FLAT-LINE IN TEMPERATURES THIS AFTERNOON AS THE COOL FRONT PORTION OF THIS TROUGH WORKS THROUGH. NORTHWEST WINDS IN THE BOUNDARY LAYER WILL BE RIGHT AT THE CUSP AT KEEPING A LAKE BREEZE AT BAY FOR CHICAGO BUT SOME COOLING OF SEVERAL DEGREES COULD BE SEEN BY MID-AFTERNOON IMMEDIATELY NEAR THE IL LAKESHORE AND DEFINITELY NEAR THE IN SHORE. THURSDAY THROUGH FRIDAY...A QUIET TIME AS SURFACE HIGH PRESSURE ON THE ORDER OF 1019 MB MOVES ATOP THE AREA. THERE SHOULD BE LIMITED CIRRUS AND ONLY FEW CU DURING THE AFTERNOONS. A MODEL BLEND TYPICALLY DOES VERY WELL FOR TEMPS IN THIS TYPE OF CALM REGIME AND HAVE BLENDED THAT WITH GOING FORECAST. TEMPERATURES SHOULD BE WITHIN A COUPLE DEGREES OF OR RIGHT AT NORMAL. THIS WEEKEND INTO EARLY NEXT WEEK...THE TREND IN LONG RANGE GUIDANCE CONTINUES TO POINT TOWARD A WARMER AND DRIER TIME THAN SOLUTIONS FROM A COUPLE DAYS AGO WITH STOUT UPPER RIDGING FROM THE WEST SOUTHWEST STRETCHING OVER THE AREA. THE ADVANCING RIDGE FROM THE WEST LATE THIS WEEK GETS HELD UP WITH BOTH A CLOSED LOW IN THE NORTHEAST/MID-ATLANTIC AND TROPICAL STORM CHANTAL...FORECAST BY NHC TO BE NEAR THE GA/SC SHORE BY LATE SUNDAY. 500MB HEIGHTS IN EXCESS OF 594DM ARE FORECAST BY BOTH THE EC AN GFS FOR THE WEEKEND. WHILE THE EC WEAKENS THIS MORE THAN THE GFS EARLY NEXT WEEK...THE PATTERN FORECAST IS STILL BLOCKED AND RIDGE RIDING ACTIVITY IS FORECAST FOR MOST OF THIS TIME FAIRLY FAR NORTH. BUT AS WE SAW IN THE JUNE 22-26 STRETCH...THAT CAN EVOLVE FURTHER SOUTH THAN LONG RANGE SOLUTIONS SHOW AS MULTIPLE ROUNDS OF CONVECTION FIRE. BUT THIS IS CERTAINLY A STRONGER RIDGE FORECAST THIS FAR NORTHEAST. THE 850MB 20C TEMP CONTOUR FLIRTS WITH THE CWA ON BOTH SOLUTIONS FROM SAT THROUGH TUE. HAVE BOOSTED TEMPS A COUPLE DEGREES FURTHER AND IF THAT THERMAL RIDGE ENDS UP FURTHER SOUTH UNCONTAMINATED WITH CONVECTIVE CLOUDS...CAN CERTAINLY ENVISION AT LEAST LOW 90S AWAY FROM THE LAKE FOR MULTIPLE DAYS. BUT CONFIDENCE ENVELOPE...WHILE NOT OVERLY LARGE...IS CENTERED MORE ON UPPER 80S /LOW-MID NEAR THE LAKE/. THE EASTERN ATLANTIC/GULF FLOW LOOKS TO RETURN HIGHER DEW POINTS BY SUN OR MON. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * VARIABLE WINDS BETWEEN APPROX 350 AND 020 THROUGH EARLY AFTERNOON WITH SPORADIC GUSTS TO THE MID TEENS. * STEADIER NORTHEAST WIND EXPECTED WITH LAKE PUSH MID AFTERNOON. MDB //DISCUSSION...UPDATED 16Z. WINDS REMAIN THE MAIN ISSUE THROUGH THE AFTERNOON...MAINLY ACROSS THE CHICAGO AND NW INDIANA AREA. PRESSURE GRADIENT HAS ALIGNED AS TO ALLOW A MORE NORTHERLY DIRECTION TO SET UP CLOSE TO THE LAKE WITH A LAKE BREEZE ALSO DEVELOPING AND SLOWLY PUSHING INLAND. THIS SHOULD SUPPORT SOME VARIABILITY IN WIND DIRECTION AT ORD/MDW OVER THE NEXT FEW HOURS BETWEEN ROUGHLY 350 AND 020. THIS WILL LIKELY CONTINUE UNTIL THE LAKE BREEZE CAN WORK ITS WAY INLAND TURNING WINDS NORTHEAST WHICH IS EXPECTED TO OCCUR MID AFTERNOON. IT IS POSSIBLE THAT CONVERGENCE COULD SET UP JUST EAST OF THE TERMINALS ALLOWING THEM TO TURN MORE NNW BUT THIS APPEARS TO BE ESTABLISHING ITSELF WEST OF THE TERMINALS AT THIS TIME. MDB FROM 12Z... AS THE FRONTAL BOUNDARY IS CURRENTLY SOUTH OF THE TERMINALS THIS MORNING...THE SHOWER/TS DEVELOPMENT ACROSS CENTRAL ILLINOIS WILL REMAIN SOUTH OF THE TERMINALS TODAY. ALTHOUGH WITH FROPA AND A WEAK GRADIENT IN PLACE...SOME SCATTERED LOWER CEILINGS AND FOG REMAIN NEAR THE TERMINALS. WITH THE SUN QUICKLY RISING THIS MORNING...ANY LINGERING FOG/CEILINGS SHOULD QUICKLY DIMINISH WITH LATEST SATELLITE IMAGERY ALREADY SHOWING THIS OCCURRING. ALTHOUGH IT WOULD NOT BE OUT OF THE QUESTION FOR A BRIEF PERIOD OF LOWER CEILINGS AROUND 2KFT OVER THE NEXT HOUR...MAINLY FOR MDW/GYY. ANY FURTHER CLOUD DEVELOPMENT TODAY SHOULD REMAIN SCATTERED AS DRIER AIR CONTINUES TO PUSH SOUTH ON INCREASING NORTHWEST WINDS THIS MORNING. RFD AND DPA SHOULD REMAIN NORTHWEST WITH GUSTS INCREASING BY MID MORNING...WITH ORD/MDW/GYY LIKEWISE OBSERVING THIS TREND BUT ONLY THROUGH THE MORNING. EXPECT A TREND TOWARDS A NORTHEAST DIRECTION BY EARLY AFTERNOON FOR ORD/MDW/GYY...REMAINING THIS DIRECTION UNTIL LATER THIS EVENING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM CONFIDENCE IN VARIABLE 350-020 WINDS. * MEDIUM CONFIDENCE IN A STEADIER NORTHEAST WIND DEVELOPING MID AFTERNOON...MEDIUM CONFIDENCE IN TIMING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. TUESDAY...VFR. RODRIGUEZ && .MARINE... 416 AM CDT AS A TROUGH OF LOW PRESSURE AND ASSOCIATED COLD FRONT BEGIN TO PUSH EAST ACROSS THE NORTHERN PORTIONS OF THE LAKE THIS MORNING...A FAIRLY TIGHT PRESSURE GRADIENT HAS HELPED SOUTHWEST WINDS TO INCREASE TO 15 TO 25 KT OVER THE NORTHERN PORTIONS OF THE LAKE WHILE AREAS FURTHER SOUTH ARE OBSERVING SPEEDS OF 10 TO 20 KT. AS THIS TROUGH/FRONT CONTINUE SOUTHEAST DOWN THE LAKE THIS MORNING...EXPECT THESE SOUTHWEST WINDS TO SHIFT TO THE WEST/NORTHWEST AND THEN HOLD ONTO A NORTHWEST DIRECTION FOR THE REMAINDER OF THE DAY INTO TONIGHT. EXPECT LIGHT NORTHERLY FLOW OVER THE LAKE FOR MOST OF THURSDAY AS HIGH PRESSURE SLOWLY SHIFTS EAST TOWARDS THE CENTRAL GREAT LAKES. BY FRIDAY WINDS TURN BACK TO A SOUTHERLY DIRECTION...AS THIS HIGH SETTLES OVER THE EASTERN GREAT LAKES INTO THE WEEKEND. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1209 PM CDT WED JUL 10 2013 ...UPDATED SYNOPSIS AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1206 PM CDT WED JUL 10 2013 AT 12Z WEDNESDAY A 500MB HIGH WAS LOCATED NEAR THE FOUR CORNERS AREA WITH SEVERAL THERMAL TROUGHS LOCATED AROUND THIS HIGH. ONE APPEARS TO BE LOCATED IN NORTHWEST COLORADO AND ANOTHER IN NEVADA. AT THE 700MB LEVEL TEMPERATURES ACROSS THE CENTRAL PLAINS VARIED FROM 11C AT NORTH PLATTE TO 13C AT DODGE CITY TO 14C AT DENVER. A WEDGE OF HIGHER DEWPOINTS WERE OBSERVED FROM THE PANHANDLE OF TEXAS, ACROSS EASTERN COLORADO INTO SOUTHWEST SOUTH DAKOTA. A 850MB FRONT APPEARS TO BE LOCATED FROM SOUTHEAST WYOMING ACROSS NORTHERN KANSAS INTO NORTHERN MISSOURI WITH +24C REPORTED SOUTH OF THIS FRONT AT DODGE CITY AND TOPEKA. A SURFACE COLD FRONT WAS LOCATED FROM SOUTHEAST COLORADO INTO WESTERN OKLAHOMA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 314 AM CDT WED JUL 10 2013 THE FORECAST FOR TODAY AND TONIGHT WILL BE CHALLENGING WITH REGARDS TO PLACEMENT, TIMING, AND INTENSITY OF THUNDERSTORMS. THE COLD FRONT WILL STALL OUT AND DISSOLVE AS IT APPROACHES THE OKLAHOMA BORDER TODAY. WINDS NORTH OF THE FRONT WILL BECOME EAST AND EVENTUALLY SOUTHEAST...ESPECIALLY ALONG THE COLORADO BORDER. A RICH SOURCE OF LOW LEVEL MOISTURE WILL BE IN PLACE NORTH OF THE FRONT WITH SURFACE DEWPOINTS IN THE MID TO UPPER 60S ACROSS PORTIONS OF CENTRAL AND WESTERN KANSAS. DESPITE THE PASSAGE OF THE COLD FRONT AND BEING ON THE NORTH SIDE OF THE BOUNDARY...AFTERNOON TEMPERATURES WILL STILL REACH THE 95 TO 98F RANGE ACROSS MUCH OF THE SOUTHWEST KANSAS REGION WITH STILL FAIRLY HIGH LOW LEVEL THICKNESSES. LOWER TROPOSPHERIC CONVERGENCE ALONG THE OLD FRONTAL ZONE ACROSS FAR SOUTHWEST KANSAS NEAR THE OKLAHOMA BORDER WILL AID IN FORMATION OF AFTERNOON THUNDERSTORMS. THERE WILL BE A GREATER AMOUNT OF SBCAPE TODAY WITH MUCH HIGHER DEWPOINT VALUES/MOISTURE CONTENT OVER YESTERDAY. THIS WOULD ARGUE FOR MORE ORGANIZED CONVECTION. ONE OR MORE MESOSCALE CONVECTIVE SYSTEMS (MCS) MAY DEVELOP FROM SOUTHWEST KANSAS NORTH-NORTHWESTWARD TO THE CHEYENNE RIDGE AREA. THE GREATER RISK FOR SEVERE STORMS WILL BE FARTHER NORTH (MOSTLY NORTH OF THE DDC FORECAST AREA) WHERE DEEP LAYER SHEAR WILL SUPPORT MORE ORGANIZED MULTI-CELL CLUSTERS AND PERHAPS A SUPERCELL OR TWO. WILL KEEP POPS IN THE 30 TO 40 PERCENT TERRITORY GIVEN THE UNCERTAINTY OF PLACEMENT AND COVERAGE OF THUNDERSTORM CLUSTERS/EVENTUAL MCS...HOWEVER POPS MAY NEED TO BE INCREASED FOR SOME SECTIONS OF THE FORECAST AREA AS SHORT TERM HIGHER RESOLUTION MODELS LIKE THE HRRR GET A BETTER HANDLE ON THE ENVIRONMENT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 400 AM CDT WED JUL 10 2013 THE EXTENDED PERIOD IS DRY AND HOT. ON THURSDAY, LEE TROUGHING AND WARM AIR ADVECTION ALONG WITH 850 HPA TEMPS IN THE 20S DEG C WILL SUPPORT MAXIMUMS IN THE MID TO UPPER 90S DEG F. NO PRECIPITATION IS EXPECTED. ON FRIDAY, THE 850 HPA WARM PLUME WILL SPREAD FARTHER NORTH AND EAST WITH 850 HPA TEMPERATURES FLIRTING WITH 30 DEG C. THIS SUPPORTS MIX DOWN TEMPERATURES IN THE LOW 100S DEG F FRIDAY AND SATURDAY. MINIMUMS WILL BE IN THE 70S DEG F THROUGH THIS PERIOD. ON SUNDAY, A JET STREAK MOVING ACROSS THE NORTHERN PLAINS INTO THE CENTRAL CANADIAN PRAIRIE PROVINCES WILL USHER IN THE PASSAGE OF A COLD FRONT ACROSS NEBRASKA AND WILL STALL OUT ACROSS THE CORNHUSKER STATE. THIS COULD KNOCK DOWN TEMPERATURES LOCALLY A FEW DEGREES. BOTH THE GFS AND ECMWF SHOW CONVECTION ASSOCIATED WITH THE FRONT AND ANY POST FRONTAL/OROGRAPHIC CONVECTION REMAINING WELL WEST/NORTHWEST OF THE AREA. AS RESULT, WENT WITH AOB 14 PERCENT PRECIPITATION PROBABILITY PERCENTAGE POINTS. THEREAFTER, THE RIDGE WILL CONTINUE TO DOMINATE WITH DRY AND HOT CONDITIONS PREVAILING. THERE COULD BE RETROGRESSION OF A SUBTROPICAL LOW NEXT WEEK, BUT THIS WILL NOT HAVE ANY SIGNIFICANT IMPACTS TO SW KANSAS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1206 PM CDT WED JUL 10 2013 A SURFACE FRONT WILL EXTEND FROM SOUTHEAST COLORADO INTO WESTERN OKLAHOMA. NORTH OF THIS FRONT AN EASTERLY WIND WILL CONTINUE AT 10 TO 15KTS ACROSS SOUTHWEST KANSAS THROUGH 00Z THURSDAY. THESE EASTERLY WINDS WILL THEN BEGIN TO GRADUALLY VEER TO THE SOUTHEAST EARLY TONIGHT. CONVECTION IS EXPECTED TO DEVELOP ACROSS EASTERN COLORADO LATER THIS AFTERNOON AND THEN SPREAD EAST/SOUTHEAST ACROSS WESTERN KANSAS OVERNIGHT. LATEST MODELS SUGGEST THE BETTER OPPORTUNITY FOR CONVECTION AT GCK AND DDC WILL BE BETWEEN 00Z AND 06Z AND AT HYS BETWEEN 03Z AND 09Z. BASED ON LATEST BUFR SOUNDINGS THE CLOUD BASES WILL BE ABOVE 5000FT SO VFR CONDITIONS ARE EXPECTED. && .PRELIMINARY POINT TEMPS/POPS... DDC 96 70 97 73 / 30 40 10 0 GCK 94 69 98 73 / 30 40 0 0 EHA 95 69 98 72 / 30 30 0 10 LBL 97 70 99 72 / 30 30 0 0 HYS 93 69 95 73 / 20 30 20 0 P28 99 72 98 73 / 20 30 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...UMSCHEID LONG TERM...SUGDEN AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS JACKSON KY
601 PM EDT WED JUL 10 2013 .UPDATE... ISSUED AT 600 PM EDT WED JUL 10 2013 HAVE HAD ONLY 1 REPORT OF WIND DAMAGE SO FAR...AND SEVERE THREAT IS DIMINISHING. WILL BE UPDATING NDFD FOR LATEST OBSERVATIONAL TRENDS AND FOR CURRENT MOVEMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. PLAN TO BEGIN TRIMMING COUNTIES FROM THE SEVERE THUNDERSTORM WATCH ON THE WESTERN PART OF THE FORECAST AREA. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 304 PM EDT WED JUL 10 2013 WILL ADD PIKE...LETCHER AND HARLAN COUNTY TO FLASH FLOOD WATCH. WITH CONVECTION IN THESE AREAS ALREADY OCCURRING TODAY...THEY WILL BE PRIMED FOR POTENTIAL FLASH FLOODING WITH ADDITIONAL ACTIVITY THIS EVENING AND OVERNIGHT. COLD FRONT CURRENTLY IN NORTHWEST INDIANA WILL BE ONLY SLOWLY PRESSING SOUTHEAST OVERNIGHT AND NOT CLEARING SOUTHEAST KY UNTIL THURSDAY AFTERNOON. LATEST MODEL GUIDANCE AND ESPECIALLY CURRENT RADAR TRENDS POINTING TOWARDS MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS FROM LATE THIS AFTERNOON INTO TONIGHT. PRECIPITABLE WATER AROUND 1.8 THIS AFTERNOON AND WILL NOT SEE MUCH DECREASE UNTIL AFTER FRONTAL PASSAGE ON THURSDAY...AND THUNDERSTORMS WILL CONTINUE TO BE CAPABLE OF PRODUCING VERY HEAVY RAIN. CONSIDERABLE DESTABILIZATION HAS OCCURRED THIS AFTERNOON AND SEVERE THREAT ALSO INCREASING...WITH SEVERE REPORTS ALREADY OCCURRING IN CENTRAL KY. HRRR IS POINTING TOWARDS ACTIVITY OVER CENTRAL KY MERGING INTO A BOWING LINE WHICH WOULD INCREASE SEVERE THREAT OVER SE KY EARLY THIS EVENING. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 334 PM EDT WED JUL 10 2013 THERE IS DECENT AGREEMENT WITH THE VARIOUS MODELS HOWEVER THERE IS SOME CONCERN WITH THE RESIDUAL UPPER TROUGH THAT DOES NOT WANT TO GO AWAY. THE MODELS ARE SHOWING THE UPPER TROUGH INITIALLY MOVING TO THE EAST. THIS WILL BRING SOME DRIER AND COOLER AIR TO THE AREA FOR A WHILE...BUT THEN THE MODELS SHOW THE REMNANTS OF THE UPPER LOW OVER OHIO ON SUNDAY. THE LOW THEN MEANDERS SOUTH OVER TIME. WITH ALL THE SOLUTIONS...ALL THE FRONTS WILL STAY NORTH OF THE AREA AND EASTERN KENTUCKY WILL JUST BE GENERAL AIR MASS CONVECTIVE ACTIVITY AND WILL BE FAIRLY WARM AND HUMID. THE CONFIDENCE TENDS TO GO DOWN AFTER SUNDAY FOR THE REST OF THE PERIOD BECAUSE IT WILL BE SO HARD TO TELL WHERE THE AREAS OF ORGANIZED CONVECTION WILL BE. IN GENERAL WENT WITH A MODEL BLEND...HOWEVER DID AN EXTRA NUDGE TOWARD THE ECMWF. FOR TEMPERATURES...WENT A BIT COOLER THAN THE MODEL BLEND FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME STAYING CLOSER TO THE ECMWF RAW OUTPUT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 131 PM EDT WED JUL 10 2013 COLD FRONT CURRENTLY OVER FAR NORTHWEST INDIANA WILL SLOWLY PRESS SOUTHEAST OVER THE NEXT 24 HOURS...CLEARING SOUTHEAST KY THURSDAY AFTERNOON. NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR AHEAD OF THE COLD FRONT...WITH ALL TAF SITES EXPECTED TO BE AFFECTED LATE THIS AFTERNOON AND INTO THE OVERNIGHT PERIOD. OUTSIDE OF THUNDERSTORMS MOST AREAS WILL SEE VFR CONDITIONS THIS AFTERNOON...BUT AFTER MORE WIDESPREAD PRECIPITATION MOVES IN LATER DO EXPECT CONDITIONS TO DETERIORATE TONIGHT TO MVFR TO IFR. CONDITIONS SHOULD IMPROVE BACK TO VFR BEFORE 18Z ON THURSDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...SBH SHORT TERM...SBH LONG TERM...JJ AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
334 PM EDT WED JUL 10 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 304 PM EDT WED JUL 10 2013 WILL ADD PIKE...LETCHER AND HARLAN COUNTY TO FLASH FLOOD WATCH. WITH CONVECTION IN THESE AREAS ALREADY OCCURRING TODAY...THEY WILL BE PRIMED FOR POTENTIAL FLASH FLOODING WITH ADDITIONAL ACTIVITY THIS EVENING AND OVERNIGHT. COLD FRONT CURRENTLY IN NORTHWEST INDIANA WILL BE ONLY SLOWLY PRESSING SOUTHEAST OVERNIGHT AND NOT CLEARING SOUTHEAST KY UNTIL THURSDAY AFTERNOON. LATEST MODEL GUIDANCE AND ESPECIALLY CURRENT RADAR TRENDS POINTING TOWARDS MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS FROM LATE THIS AFTERNOON INTO TONIGHT. PRECIPITABLE WATER AROUND 1.8 THIS AFTERNOON AND WILL NOT SEE MUCH DECREASE UNTIL AFTER FRONTAL PASSAGE ON THURSDAY...AND THUNDERSTORMS WILL CONTINUE TO BE CAPABLE OF PRODUCING VERY HEAVY RAIN. CONSIDERABLE DESTABILIZATION HAS OCCURRED THIS AFTERNOON AND SEVERE THREAT ALSO INCREASING...WITH SEVERE REPORTS ALREADY OCCURRING IN CENTRAL KY. HRRR IS POINTING TOWARDS ACTIVITY OVER CENTRAL KY MERGING INTO A BOWING LINE WHICH WOULD INCREASE SEVERE THREAT OVER SE KY EARLY THIS EVENING. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 334 PM EDT WED JUL 10 2013 THERE IS DECENT AGREEMENT WITH THE VARIOUS MODELS HOWEVER THERE IS SOME CONCERN WITH THE RESIDUAL UPPER TROUGH THAT DOES NOT WANT TO GO AWAY. THE MODELS ARE SHOWING THE UPPER TROUGH INITIALLY MOVING TO THE EAST. THIS WILL BRING SOME DRIER AND COOLER AIR TO THE AREA FOR A WHILE...BUT THEN THE MODELS SHOW THE REMNANTS OF THE UPPER LOW OVER OHIO ON SUNDAY. THE LOW THEN MEANDERS SOUTH OVER TIME. WITH ALL THE SOLUTIONS...ALL THE FRONTS WILL STAY NORTH OF THE AREA AND EASTERN KENTUCKY WILL JUST BE GENERAL AIR MASS CONVECTIVE ACTIVITY AND WILL BE FAIRLY WARM AND HUMID. THE CONFIDENCE TENDS TO GO DOWN AFTER SUNDAY FOR THE REST OF THE PERIOD BECAUSE IT WILL BE SO HARD TO TELL WHERE THE AREAS OF ORGANIZED CONVECTION WILL BE. IN GENERAL WENT WITH A MODEL BLEND...HOWEVER DID AN EXTRA NUDGE TOWARD THE ECMWF. FOR TEMPERATURES...WENT A BIT COOLER THAN THE MODEL BLEND FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME STAYING CLOSER TO THE ECMWF RAW OUTPUT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 131 PM EDT WED JUL 10 2013 COLD FRONT CURRENTLY OVER FAR NORTHWEST INDIANA WILL SLOWLY PRESS SOUTHEAST OVER THE NEXT 24 HOURS...CLEARING SOUTHEAST KY THURSDAY AFTERNOON. NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR AHEAD OF THE COLD FRONT...WITH ALL TAF SITES EXPECTED TO BE AFFECTED LATE THIS AFTERNOON AND INTO THE OVERNIGHT PERIOD. OUTSIDE OF THUNDERSTORMS MOST AREAS WILL SEE VFR CONDITIONS THIS AFTERNOON...BUT AFTER MORE WIDESPREAD PRECIPITATION MOVES IN LATER DO EXPECT CONDITIONS TO DETERIORATE TONIGHT TO MVFR TO IFR. CONDITIONS SHOULD IMPROVE BACK TO VFR BEFORE 18Z ON THURSDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...SBH LONG TERM...JJ AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
304 PM EDT WED JUL 10 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 304 PM EDT WED JUL 10 2013 WILL ADD PIKE...LETCHER AND HARLAN COUNTY TO FLASH FLOOD WATCH. WITH CONVECTION IN THESE AREAS ALREADY OCCURRING TODAY...THEY WILL BE PRIMED FOR POTENTIAL FLASH FLOODING WITH ADDITIONAL ACTIVITY THIS EVENING AND OVERNIGHT. COLD FRONT CURRENTLY IN NORTHWEST INDIANA WILL BE ONLY SLOWLY PRESSING SOUTHEAST OVERNIGHT AND NOT CLEARING SOUTHEAST KY UNTIL THURSDAY AFTERNOON. LATEST MODEL GUIDANCE AND ESPECIALLY CURRENT RADAR TRENDS POINTING TOWARDS MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS FROM LATE THIS AFTERNOON INTO TONIGHT. PRECIPITABLE WATER AROUND 1.8 THIS AFTERNOON AND WILL NOT SEE MUCH DECREASE UNTIL AFTER FRONTAL PASSAGE ON THURSDAY...AND THUNDERSTORMS WILL CONTINUE TO BE CAPABLE OF PRODUCING VERY HEAVY RAIN. CONSIDERABLE DESTABILIZATION HAS OCCURRED THIS AFTERNOON AND SEVERE THREAT ALSO INCREASING...WITH SEVERE REPORTS ALREADY OCCURRING IN CENTRAL KY. HRRR IS POINTING TOWARDS ACTIVITY OVER CENTRAL KY MERGING INTO A BOWING LINE WHICH WOULD INCREASE SEVERE THREAT OVER SE KY EARLY THIS EVENING. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 304 PM EDT WED JUL 10 2013 UPDATED DISCUSSION WILL FOLLOW SHORTLY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 131 PM EDT WED JUL 10 2013 COLD FRONT CURRENTLY OVER FAR NORTHWEST INDIANA WILL SLOWLY PRESS SOUTHEAST OVER THE NEXT 24 HOURS...CLEARING SOUTHEAST KY THURSDAY AFTERNOON. NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR AHEAD OF THE COLD FRONT...WITH ALL TAF SITES EXPECTED TO BE AFFECTED LATE THIS AFTERNOON AND INTO THE OVERNIGHT PERIOD. OUTSIDE OF THUNDERSTORMS MOST AREAS WILL SEE VFR CONDITIONS THIS AFTERNOON...BUT AFTER MORE WIDESPREAD PRECIPITATION MOVES IN LATER DO EXPECT CONDITIONS TO DETERIORATE TONIGHT TO MVFR TO IFR. CONDITIONS SHOULD IMPROVE BACK TO VFR BEFORE 18Z ON THURSDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ044-050>052- 058>060-068-069-079-080-083>087-104-106>117-119. && $$ SHORT TERM...SBH LONG TERM...JJ AVIATION...SBH
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
115 PM EDT WED JUL 10 2013 ...Updated Aviation Discussion... .FORECAST UPDATE... Issued at Noon EDT Wed Jul 10 2013 After coordination with neighboring offices, decided to go ahead with a flash flood watch in the areas that had the lowest 1-hour flash flood guidance over the eastern forecast area. The I-65 corridor around Louisville has higher guidance, but with timing of storms around the afternoon rush hour decided to err on the side of caution and throw them in as well. Bust potential on the western side of the area is how long the subsidence from the decaying storms over Illinois continues to keep a cap over that area. Still, surface temperatures are rising quickly over our area, so CAPEs already are up around 3-4 thousand. All we need is a trigger to get these storms to push through, and still think that will be from the north. Issued at 945 AM EDT Wed Jul 10 2013 Local WRF and to some extent the HRRR pick up well on current spread of convection out to our west and north this morning. Bumped up pops a little over my southwest zones, where some scattered storms have popped up this morning. Cloud cover is coming in ahead of the central Illinois convection as well as with the cells to our west. These clouds should help to temper our highs some today, but dewpoints are fairly highs, so heat indices likely still will top out in the mid/upper 90s, perhaps even 100 in the SDF metro. Storms firing off to our west indicate somewhat of an uncapped atmosphere, but AMDAR sounding out of SDF has a weak cap at 800 mb, possibly from sinking air with the cirrus shield our ahead of those storms in central Illinois. As of this writing, that subsidence looks like it is weakening the cells just west of Hancock and Ohio counties. Think this cap will be long enough to allow what the local WRF shows as a line of storms moving in from the north later this afternoon. By then soundings indicate plenty of CAPE despite the cloud cover, so these storms will have enough instability to stay together and producing damaging winds and possibly some hail. We`ll have to get fairly tall storms to get the hail to survive down to the surface, given a very moist airmass in place. && .SHORT TERM (Now through Thursday)... Issued at 316 AM EDT Wed Jul 10 2013 ...Strong to Severe Storms Likely This Afternoon Along With Locally Heavy Rainfall... In the near term, passing mid-level wave now in Ohio will continue to track eastward early this morning. Bulk of the convection associated with the wave will pass northeast of our area, but some isolated-scattered showers will be possible mainly across our eastern half this morning. Clouds are rapidly clearing out to the west, so we should see some partial clearing by sunrise in the central and western sections. Temperatures will remain for the remainder of the night with readings bottoming out in the lower-middle 70s in most locations with upper 70s being more likely down in the urban centers. Next mid-level wave within the mean flow will approach the region later this morning and into the afternoon hours. Expect convection to develop over the next few hours from MO into IL with much of region remaining fairly dry. In fact, it appears that we`ll likely see some partly to mostly sunny skies this morning which will allow solar insolation to really get temperatures warmed up. By mid-late morning, convection to our northwest will begin to push eastward. As the mid-level wave and associated surface boundary approach, we expect convection to become more widespread during the afternoon and into the evening hours. Regarding convective potential and intensity, much of our region will reside on the southern edge of the westerlies this afternoon. This places much of the better shear to our north. However, with the expected insolation this morning, we should see temperatures warm into the upper 80s and perhaps lower 90s in some spots. This combined with dewpoints in the lower-mid 70s will result in strong instability developing as cooler mid-level temperatures overspread the region. Convection will probably be multi-modal with lines and segments being likely. Given the decreasing shear profile from NE to SW across our region, it appears that damaging winds/microbursts and large hail will be the primary severe weather threats across our region. With the wet ground in many places in central KY, sub-severe winds could easily result in trees coming down fairly easily. In addition to the severe weather threat, precipitable water values are still forecast to run quite high this afternoon with readings in the 1.9-2.0 inch range. This will result in locally heavy rainfall with any of the storms that develop. Given the rainfall over the past weekend, we are still dealing with fairly wet grounds. Thus, the torrential rainfall with this afternoon`s storms will have the capability of producing flash flooding. The storms look to have some movement to them, so the flooding threat could be more attributed to training of cells as well. Showers and thunderstorms are expected to continue into the evening hours, but should diminish with the loss of daytime heating this evening. We should see a diminishing trend of PoPs from NW to SE through the overnight hours with much of southern Indiana and western/NC KY going dry by Thursday morning. Overnight lows will cool into the 60s. A few scattered storms will be possible across the east/southeast Thursday morning and into the early afternoon hours, but most locations should see dry conditions by Thursday evening. Highs Thursday will be cooler than Wednesday with readings in the lower 80s. .LONG TERM (Thursday Night through Tuesday)... Issued at 302 AM EDT Wed Jul 10 2013 Drier and cooler air will be working its way into the area Thursday night in the wake of the cold front. At the surface high pressure will build in across the Ohio Valley through Friday. A trough aloft will keep the region in northwesterly flow through Friday, before a ridge builds across the Great Lakes region. Dry conditions look to prevail through the weekend, though diurnal storms will begin creeping back towards the far southeastern portions of the forecast area by Sunday afternoon. Temperatures will be coolest at the beginning of the period. Lows on Friday morning will be in the low to mid 60s with highs in the low to mid 80s. By Sunday lows will be in the upper 60s with highs in the upper 80s. Moisture return will continue through the beginning of the next work week. Isolated to scattered afternoon thunderstorms will be possible Monday and Tuesday afternoons, especially across south central Kentucky. Temperatures will continue the slow warming trend with highs in the upper 80s to lower 90s by Tuesday and lows in the lower 70s. && .AVIATION (18Z TAF Update)... Issued at 115 PM EDT Wed Jul 10 2013 Atmosphere becoming more unstable with heating and high low-level humidity. Have storms firing up near each of the sites, though closest to SDF this hour. Expect a more solid line to move in from the north, though if the more isolated convection over Kentucky becomes more widespread that will poke some holes in anything moving in from the north. For now have tried to place the timing of this line into each of the sites with stronger wind gusts and IFR restrictions. Lingering moisture overnight may lead to some MVFR cigs and vsby into daybreak. Expect a front to pass through the sites late this evening, bringing more solid northerly winds during the day Thursday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR INZ077>079-091-092. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ029>043-045>049- 053>057-064>067-076>078-081-082. $$ Updates..........RJS Short Term.......MJ Long Term........EER Aviation.........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1205 PM EDT WED JUL 10 2013 .FORECAST UPDATE... Issued at Noon EDT Wed Jul 10 2013 After coordination with neighboring offices, decided to go ahead with a flash flood watch in the areas that had the lowest 1-hour flash flood guidance over the eastern forecast area. The I-65 corridor around Louisville has higher guidance, but with timing of storms around the afternoon rush hour decided to err on the side of caution and throw them in as well. Bust potential on the western side of the area is how long the subsidence from the decaying storms over Illinois continues to keep a cap over that area. Still, surface temperatures are rising quickly over our area, so CAPEs already are up around 3-4 thousand. All we need is a trigger to get these storms to push through, and still think that will be from the north. Issued at 945 AM EDT Wed Jul 10 2013 Local WRF and to some extent the HRRR pick up well on current spread of convection out to our west and north this morning. Bumped up pops a little over my southwest zones, where some scattered storms have popped up this morning. Cloud cover is coming in ahead of the central Illinois convection as well as with the cells to our west. These clouds should help to temper our highs some today, but dewpoints are fairly highs, so heat indices likely still will top out in the mid/upper 90s, perhaps even 100 in the SDF metro. Storms firing off to our west indicate somewhat of an uncapped atmosphere, but AMDAR sounding out of SDF has a weak cap at 800 mb, possibly from sinking air with the cirrus shield our ahead of those storms in central Illinois. As of this writing, that subsidence looks like it is weakening the cells just west of Hancock and Ohio counties. Think this cap will be long enough to allow what the local WRF shows as a line of storms moving in from the north later this afternoon. By then soundings indicate plenty of CAPE despite the cloud cover, so these storms will have enough instability to stay together and producing damaging winds and possibly some hail. We`ll have to get fairly tall storms to get the hail to survive down to the surface, given a very moist airmass in place. && .SHORT TERM (Now through Thursday)... Issued at 316 AM EDT Wed Jul 10 2013 ...Strong to Severe Storms Likely This Afternoon Along With Locally Heavy Rainfall... In the near term, passing mid-level wave now in Ohio will continue to track eastward early this morning. Bulk of the convection associated with the wave will pass northeast of our area, but some isolated-scattered showers will be possible mainly across our eastern half this morning. Clouds are rapidly clearing out to the west, so we should see some partial clearing by sunrise in the central and western sections. Temperatures will remain for the remainder of the night with readings bottoming out in the lower-middle 70s in most locations with upper 70s being more likely down in the urban centers. Next mid-level wave within the mean flow will approach the region later this morning and into the afternoon hours. Expect convection to develop over the next few hours from MO into IL with much of region remaining fairly dry. In fact, it appears that we`ll likely see some partly to mostly sunny skies this morning which will allow solar insolation to really get temperatures warmed up. By mid-late morning, convection to our northwest will begin to push eastward. As the mid-level wave and associated surface boundary approach, we expect convection to become more widespread during the afternoon and into the evening hours. Regarding convective potential and intensity, much of our region will reside on the southern edge of the westerlies this afternoon. This places much of the better shear to our north. However, with the expected insolation this morning, we should see temperatures warm into the upper 80s and perhaps lower 90s in some spots. This combined with dewpoints in the lower-mid 70s will result in strong instability developing as cooler mid-level temperatures overspread the region. Convection will probably be multi-modal with lines and segments being likely. Given the decreasing shear profile from NE to SW across our region, it appears that damaging winds/microbursts and large hail will be the primary severe weather threats across our region. With the wet ground in many places in central KY, sub-severe winds could easily result in trees coming down fairly easily. In addition to the severe weather threat, precipitable water values are still forecast to run quite high this afternoon with readings in the 1.9-2.0 inch range. This will result in locally heavy rainfall with any of the storms that develop. Given the rainfall over the past weekend, we are still dealing with fairly wet grounds. Thus, the torrential rainfall with this afternoon`s storms will have the capability of producing flash flooding. The storms look to have some movement to them, so the flooding threat could be more attributed to training of cells as well. Showers and thunderstorms are expected to continue into the evening hours, but should diminish with the loss of daytime heating this evening. We should see a diminishing trend of PoPs from NW to SE through the overnight hours with much of southern Indiana and western/NC KY going dry by Thursday morning. Overnight lows will cool into the 60s. A few scattered storms will be possible across the east/southeast Thursday morning and into the early afternoon hours, but most locations should see dry conditions by Thursday evening. Highs Thursday will be cooler than Wednesday with readings in the lower 80s. .LONG TERM (Thursday Night through Tuesday)... Issued at 302 AM EDT Wed Jul 10 2013 Drier and cooler air will be working its way into the area Thursday night in the wake of the cold front. At the surface high pressure will build in across the Ohio Valley through Friday. A trough aloft will keep the region in northwesterly flow through Friday, before a ridge builds across the Great Lakes region. Dry conditions look to prevail through the weekend, though diurnal storms will begin creeping back towards the far southeastern portions of the forecast area by Sunday afternoon. Temperatures will be coolest at the beginning of the period. Lows on Friday morning will be in the low to mid 60s with highs in the low to mid 80s. By Sunday lows will be in the upper 60s with highs in the upper 80s. Moisture return will continue through the beginning of the next work week. Isolated to scattered afternoon thunderstorms will be possible Monday and Tuesday afternoons, especially across south central Kentucky. Temperatures will continue the slow warming trend with highs in the upper 80s to lower 90s by Tuesday and lows in the lower 70s. && .AVIATION (12Z TAF Update)... Issued at 644 AM EDT Wed Jul 10 2013 VFR conditions are expected for early portion of the TAF period. Mid-level clouds associated with departing mid-level wave are moving out and have cleared out of the terminals. So for the next few hours, we`ll see mostly clear skies but should see a cu field develop toward late morning. Surface cold front and next mid-level wave are currently out to our west and are heading eastward. These features will impact the region this afternoon during peak heating. This should result in convective development across the region. Still a little uncertain with regards to overall convective evolution, so plan on going with VCTS at the terminals after 10/18Z. Convection will likely linger into the evening/overnight hours before diminishing. Outside of storms, VFR conditions will prevail, but if a storm impacts the terminal, a drop to IFR conditions due to heavy rain is likely. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR INZ077>079-091-092. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ029>043-045>049- 053>057-064>067-076>078-081-082. $$ Updates..........RJS Short Term.......MJ Long Term........EER Aviation.........MJ
AREA FORECAST DISCUSSION
NWS GRAY ME
616 PM EDT WED JUL 10 2013 .SYNOPSIS... A WARM FRONT WILL PUSH NORTHEAST ACROSS THE REGION EARLY TONIGHT WITH A COLD FRONT PUSHING EAST ACROSS THE REGION LATE TONIGHT. THE COLD FRONT WILL STALL JUST OFF THE COAST THURSDAY AND THURSDAY NIGHT. LOW PRESSURE WILL TRACK JUST OFFSHORE ALONG THE STALLED FRONT LATE FRIDAY AND FRIDAY NIGHT. THE FRONT WILL WASHOUT OVER THE WEEKEND AS HIGH PRESSURE ANCHORED OFFSHORE BUILDS WESTWARD INTO THE REGION. && .NEAR TERM /THROUGH THURSDAY/... UPDATE... HAVE UPDATED THE GRIDS TO ADD FOG FOR PORTIONS OF THE COASTLINE AND THE COASTAL WATERS. VSBY NOW DOWN TO 1/8 MILE IN PORTLAND. HAVE ALSO ADDED HEAVY RAINFALL TO THE FORECASTS AS A QUICK ONE TO TWO INCHES OF RAIN WILL ACCUMULATE IN MANY AREAS. LATEST HRRR RUN DECREASES MOST OF THE PCPN BY AROUND 02Z OVER CENTRAL MAINE. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO SPREAD NORTHEAST. WARM FRONT IS SITUATED OVER SE NH...SO SOME OF THIS CONVECTION WILL BE WEAKENING AS IT ENTERS MAINE. SO FAR...NO HYDRO PROBLEMS AS THE PCPN IS MOVING QUICKLY ENOUGH. PREV DISC... THE WARM FRONT WILL PUSH NORTHEAST ACROSS THE FORECAST AREA EARLY TONIGHT WITH A COLD FRONT MOVING IN FROM THE WEST. THE COLD FRONT WILL MOVE THROUGH LATE TONIGHT. THESE SYSTEMS WILL PROVIDE CLOUDS AND FOG OVERNIGHT. SHOWERS AND A FEW THUNDERSTORMS, SOME WITH HEAVY RAIN, ALREADY ON RADAR POISED TO MOVE INTO NEW HAMPSHIRE THIS AFTERNOON WILL CONTINUE TO MOVE EAST ACROSS THE FORECAST AREA. HOWEVER... AS THIS CONVECTION MOVES EASTWARD INTO THE STABLE MARINE AIR OVER MAINE AND PORTIONS OF EASTERN NEW HAMPSHIRE THE INTENSITY OF THE CONVECTION WILL WEAKEN CONSIDERABLY SUCH THAT THUNDER AND HEAVY RAIN WILL LIKELY NOT OCCUR OVER MAINE. HUMID CONDITIONS WILL CONTINUE AS TEMPERATURES DON`T DROP MUCH OVERNIGHT WITH DEW POINTS IN THE 60S OVER MAINE AND AROUND 70 OVER A GOOD PART OF NEW HAMPSHIRE. EXPECT OVERNIGHT LOWS IN THE 60S MOST EVERYWHERE. USED A BLEND OF MAV/MET MOS GUIDANCE FOR OVERNIGHT LOWS. QPF AMOUNTS BASED ON RFC THOUGH DID INCREASE SOME OVERNIGHT OVER SOUTHERN AREAS. MAX QPF THIS AFTERNOON THROUGH TONIGHT OVER OUR SOUTHERN NEW HAMPSHIRE ZONES WHERE THREE QUARTERS OF AN INCH IS LIKELY...THOUGH HEAVIER AMOUNTS ARE POSSIBLE WITH ANY THUNDERSTORMS. THIS AREA THAT WILL LIKELY SEE THE MOST RAINFALL HAS THE POTENTIAL FOR FLASH FLOODING IF HEAVY RAIN FALLS OVER A SHORT PERIOD OF TIME. WILL CONTINUE THE FLASH FLOOD WATCH FOR WESTERN AND SOUTHERN NEW HAMPSHIRE ZONES THROUGH 10 PM THIS EVENING. && .SHORT TERM /THURSDAY NIGHT/... THE COLD FRONT STALLS JUST OFFSHORE UNDER AN UPPER LEVEL SOUTHWEST FLOW AHEAD OF A SLOWLY APPROACHING UPPER LEVEL TROUGH. THIS STALLED FRONT KEEPS MOISTURE IN OVER OUR SOUTHEAST ZONES WHILE SOME DRIER AIR MOVES INTO NORTHWEST ZONES AS HIGH PRESSURE APPROACHES FROM CANADA AND THE GREAT LAKES REGION THURSDAY AND THURSDAY NIGHT. LOOKING FOR MORE CLOUDS AND A BETTER CHANCE OF SHOWERS ALONG THE COAST AND INTO ADJACENT INTERIOR ZONES WHILE THE NORTH AND MOUNTAIN AREAS HAVE THE LOWEST CHANCE OF RAIN AND THE LEAST AMOUNT OF CLOUDINESS. QPF BASED ON RFC GUIDANCE AND SHOULD BE MOSTLY ON THE LIGHT SIDE...THOUGH SOUTHEAST NEW HAMPSHIRE INTO COASTAL MAINE COULD SEE A 24 HOUR TOTAL THURSDAY AND THURSDAY NIGHT AROUND A THIRD OF AN INCH. USED A BLEND OF MAV/MET MOS GUIDANCE FOR TEMPERATURES WHICH WARM INTO THE MID 70S TO LOWER 80S THURSDAY AND COOL INTO THE 50S OVER THE NORTH AND MOUNTAINS WHILE ONLY DROPPING INTO THE LOWER AND MIDDLE 60S ELSEWHERE. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... THE LATEST AVAILABLE MODEL SUITE HAS THE UPPER TROUGH WEAKENING ACROSS NEW ENGLAND THIS WEEKEND BEFORE RETROGRADING TO THE SOUTH AND WEST ALLOWING THE UPPER RIDGE TO BUILD ACROSS THE REGION. SOME SIGNS THAT THE RIDGE WEAKENS TOWARDS THE END OF THE PERIOD ALLOWING A TRAILING COLD FRONT TO CROSS THE AREA WITH THE PROSPECTS FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY. OF MORE IMMEDIATE CONCERN IS THE COLD FRONT POISED TO STALL JUST OFF THE COAST EARLY IN THE PERIOD. THE MODELS SUGGEST THAT A WAVE RIDING NORTHEAST ALONG THE BOUNDARY WILL BRING SHOWERS...AND PERHAPS A PERIOD OF STEADIER RAIN TO COASTAL SECTIONS LATE FRIDAY INTO SATURDAY. OTHERWISE...SEVERAL DAYS OF HOT HUMID WEATHER WITH SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. BOTH TEMPERATURES AND PRECIPITATION ARE LIKELY TO AVERAGE ABOVE NORMAL FOR THE PERIOD. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... SHORT TERM /THROUGH THURSDAY NIGHT/...CONDITIONS LOWER TO LIFR OR AT LEAST DOWN TO IFR MOST AREAS TONIGHT IN LOW CLOUDS AND FOG WITH SOME SHOWERS AROUND THROUGH EARLY TONIGHT. POSSIBLE THUNDERSTORMS MAINLY OVER NEW HAMPSHIRE THROUGH THIS EVENING BUT PROBABILITY NOT HIGH ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. CONDITIONS IMPROVE ON THURSDAY TO MVFR AND MAYBE VFR WELL INLAND IN THE AFTERNOON. VFR TO MVFR THURSDAY NIGHT WITH POSSIBLE IFR NEAR THE COAST WHERE THERE IS A BETTER CHANCE OF SHOWERS FROM AN OFFSHORE FRONTAL SYSTEM. LONG TERM... FRI NIGHT - SAT...AREAS OF MVFR VCNTY OF THE COAST IN SHOWERS AND TSTMS. SUN - MON...SCT MVFR POSSIBLE IN SHOWERS AND TSTMS. && .MARINE... SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...CONDITIONS STAY BELOW SMALL CRAFT ADVISORY LEVELS THROUGH THE SHORT TERM. AHEAD OF AN APPROACHING COLD FRONT TONIGHT... WINDS BACK TO THE SOUTHWEST AND INCREASE TONIGHT WITH SOME GUSTS AROUND 20 KNOTS POSSIBLE. SEAS BUILD AS WELL...TO AS HIGH AS 4 FEET OVER THE OUTER WATERS. WINDS AND SEAS DROP OFF AS THE FRONT SETTLES OVER THE WATERS THURSDAY AND THURSDAY NIGHT. LONG TERM... SAT...WINDS AND SEAS MAY APPROACH SCA THRESHOLD OUTSIDE THE BAYS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NHZ003-005- 007>010-013-014. MARINE...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1245 PM CDT WED JUL 10 2013 .UPDATE... ISSUED AT 1245 PM CDT WED JUL 10 2013 LATEST RAP/HRRR SEEM TO HAVE PICKED UP ON CONVECTIVE CLUSTER ACROSS SOUTHERN MANITOBA AND DROP IT SOUTHEASTWARD THROUGH THE AFTERNOON. BASED ON THESE SOLUTIONS...REFINED POPS TO CONFINE THEM MAINLY ALONG AND NORTH OF THE HIGHWAY 2 CORRIDOR THROUGH THE EARLY EVENING. REST OF THE FORECAST IN GOOD SHAPE AT THIS TIME WITH NO CHANGES PLANNED. UPDATE ISSUED AT 1030 AM CDT WED JUL 10 2013 MAIN CONCERNS ARE PRECIPITATION CHANCES THIS AFTERNOON AND WIND SPEEDS AND RESULTING WAVE HEIGHTS ALONG THE SOUTH SHORE OF LAKE SUPERIOR. CANADIAN RADARS SHOWING AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS SOUTHERN MANITOBA IN RESPONSE TO A WELL- DEFINED SHORT WAVE VISIBLE IN THE LATEST WATER VAPOR LOOP. NO MODELS ARE CAPTURING THIS FEATURE...BUT BASED ON LATEST TRENDS... WILL ADD SOME CHANCE POPS ALONG THE CANADIAN BORDER THIS AFTERNOON. WITH NORTHWEST SURFACE FLOW...WILL NEED TO WATCH WIND SPEEDS ALONG THE SOUTH SHORE OF LAKE SUPERIOR...ESPECIALLY ACROSS THE APOSTLE ISLANDS. MODEL SOUNDINGS SHOW A DEEP AFTERNOON BOUNDARY LAYER WITH UP TO 30 KTS TO MIX TO THE SURFACE...BUT SURFACE BASED GUIDANCE SHOWS WIND SPEEDS MAXING OUT AROUND 15 KTS BY MID-AFTERNOON. WILL HOLD OFF ON ISSUANCE OF A SMALL CRAFT ADVISORY...BUT MAY NEED TO RE-EVALUATE THIS AFTERNOON. ADJUSTED SKY GRIDS TO ACCOUNT FOR ROBUST CU FIELD ACROSS THE MN ARROWHEAD. REST OF THE FORECAST IS IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. && .SHORT TERM.../NOW - TONIGHT/ AT 300AM/0800Z...THERE WAS A MID/UPPER LEVEL TROUGH CENTERED FROM WESTERN ONTARIO TO THE EASTERN FORECAST AREA. SURFACE HIGH PRESSURE WAS CENTERED IN THE WESTERN DAKOTAS. MUCH OF THE NORTHLAND HAD CLEAR SKIES...EXCEPT FOR PARTS OF THE EASTERN AND NORTHERN FORECAST AREA. MORE EXTENSIVE CLOUD COVER WAS LOCATED FARTHER NORTH AND EAST OF THE NORTHLAND...WHILE MUCH OF THE NORTHERN PLAINS HAD CLEAR SKIES. MUCH OF THE NORTHLAND HAD 5 TO 10 MPH WNW TO NW WINDS...WHICH WAS HELPING TO KEEP THE TEMPERATURES UP. THE TEMPERATURES RANGED FROM THE MID 50S TO MID 60S. TODAY...THE SURFACE HIGH PRESSURE IN THE NORTHERN PLAINS WILL BEGIN TO SHIFT EAST INTO THE UPPER MIDWEST. THE NORTHLAND CAN EXPECT RELATIVELY SUNNY AND WEATHER EARLY THIS MORNING. HOWEVER...SCATTERED CUMULUS WILL LIKELY DEVELOP BY THE AFTERNOON SINCE THE MODEL SOUNDINGS INDICATE RELATIVELY LOW CONVECTIVE TEMPERATURES IN THE BREEZY NW FLOW. THE LATEST HRRR RUNS ARE PICKING UP ON THE SCATTERED CUMULUS. ALSO...THE NAM12 AND GFS ARE SHOWING A SHORTWAVE MOVING INTO THE WESTERN FORECAST AREA THIS AFTERNOON...AND THE NAM12/DLHWRF/WRF MODELS ARE HINTING AT A LOW THREAT OF SHOWERS AND STORMS WITH THIS SHORTWAVE. I ADDED ISOLATED STORMS ACROSS THE WESTERN FORECAST AREA FOR THIS AFTERNOON AND EARLY EVENING. HIGH TEMPERATURES SHOULD BE IN THE MID 70S TO NEAR 80 DEGREES. TONIGHT...THE RELATIVELY DRY CONDITIONS THAT WILL DEVELOP THIS AFTERNOON DUE TO THE MIXING IN THE NW FLOW...COMBINED WITH THE WEAKENING WINDS TONIGHT AS HIGH PRESSURE MOVES INTO THE UPPER MIDWEST...WILL HELP FOR DECENT RADIATIONAL COOLING TONIGHT. I LOWERED THE LOW TEMPERATURE FORECAST BY A COUPLE TO FEW DEGREES. THE LOW TEMPERATURES SHOULD AROUND 50 DEGREES TO THE MID 50S...BUT I COULD SEE ISOLATED AREAS GETTING DOWN TO THE MID 40S DEPENDING ON AFTERNOON DEW POINT TEMPERATURES. DESPITE THE CLEAR SKIES AND NEGLIGIBLE WINDS THAT WILL DEVELOP...I THINK THE THREAT OF FOG IS LOW BECAUSE OF THE RELATIVELY DRY CONDITIONS THAT WILL DEVELOP IN THE AFTERNOON. IF THERE IS ANY FOG...IT WILL PROBABLY DEVELOP VERY LATE IN THE NIGHT AND BE ISOLATED. .LONG TERM.../THURSDAY - TUESDAY/ FOCUS IN EXTENDED ON RETURN OF UPPER LEVEL RIDGE AND SRLY FLOW WITH INCREASING H85 TEMPS THURSDAY NIGHT/FRIDAY...THEN STALLED BAROCLINIC ZONE THAT WILL BECOME FOCUS FOR RAIN/TSTORMS THROUGH THE WEEKEND. LONG RANGE MODELS CONTINUE TO STRUGGLE WITH THE PLACEMENT OF THE STALLED FRONT AND ASSOCIATED BAND OF PRECIPITATION. HAVE POPS MOVING INTO NW ZONES FRIDAY NIGHT...WITH WIDESPREAD HIGH CHANCE/LIKELY POPS FOR SHOWERS AND TSTORMS ACROSS THE CWA SATURDAY/SUNDAY. LATEST NAM DEPICTS VERY HIGH PWATS APPROACHING 2 INCHES SPREADS OVER THE NORTHLAND THROUGH FRIDAY EVENING. IF THE BOUNDARY DOES STALL OVER A PORTION OF THE FORECAST AREA...THE ABUNDANT MOISTURE AND PROLONGED PERIOD OF RAIN COULD LEAD TO LOCALIZED FLOODING CONCERNS. THE MAIN THREAT FOR HEAVY RAIN AT THIS TIME LOOKS TO BE FRIDAY NIGHT THROUGH SATURDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1245 PM CDT WED JUL 10 2013 VFR CONDITIONS EXPECTED TO CONTINUE ACROSS THE NORTHLAND. DID INTRODUCE VCSH AT INL AND BRD THIS EVENING WITH SMALL CONVECTIVE CLUSTER INDUCED BY SHORT WAVE ENERGY SEEN IN THE WATER VAPOR IMAGERY CURRENTLY NEAR WINNIPEG. CURRENT THINKING IS THAT AREAL COVERAGE TO REMAIN WEST OF DLH...HIB AND HYR. SOME FG/BR POTENTIAL EXISTS OVERNIGHT BUT HAVE LEFT OUT OF TAFS FOR NOW. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LSZ140-141. && $$ UPDATE...ROGERS SHORT TERM...GROCHOCINSKI LONG TERM....GRANING AVIATION...KAISER
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
1201 PM CDT WED JUL 10 2013 .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 1153 AM CDT WED JUL 10 2013 THE TRAILING MCS WHICH DEVELOPED EARLIER THIS MORNING IN THE WAKE OF THE OVERNIGHT MCS HAS NEARLY DISSIPATED. THIS SYSTEM APPEARS TO HAVE BEEN LARGELY DRIVEN BY A WESTERLY LLJ PROVIDING MESOSCALE LIFT ALONG THE WESTERN PERIPHERY OF THE INTIAL SYSTEMS OUTFLOW BOUNDARY AND WAS ALSO AIDED BY A MID LEVEL SHORT WAVE/CONVECTIVE VORT MAX. THIS MID LEVEL WAVE EXTENDED FROM EASTERN IL INTO SE MO AT 16Z AND WILL CONTINUE TO MOVE SEWD WITHIN THE NW FLOW ALOFT. THE QUESTION REMAINS IF THERE WILL BE ANY ADDITIONAL DEVELOPMENT WITH THE COLD FRONT...WHICH IS NOW LOCATED FROM AROUND PITTSFIELD TO COLUMBIA. THERE IS SOME WEAK SUBSIDENCE IN THE WAKE OF THE MID LEVEL WAVE AND CLOUDS/PRECIPITATION HAVE INHIBITED HEATING THIS MORNING. AS CLOUDS THIN THIS AFTERNOON WE WILL GET SOME HEATING AND DESTABILIZATION...BUT CURRENT INDICATIONS ARE THAT TEMPS AND INSTABILITY WILL BE LOWER THAN PREVIOUSLY ANTICIPATED AND COVERAGE OF ANY STORMS WHICH MANAGE TO DEVELOP ALONG THE COLD FRONT OR REMNANT BOUNDARY SHOULD BE LOW - ISOLATED TO WIDELY SCATTERED. GLASS .LONG TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 311 AM CDT WED JUL 10 2013 TONIGHT...SCT TSRA ALONG A CDFNT SHOULD DIMINISH WITH TIME THIS EVENING AS THE BDRY MOVES THROUGH THE AREA AND EVENTUALLY STALLS IN AR. THU THROUGH SAT...A COOLER AND DRIER AIR MASS WILL SPREAD ACROSS MO/IL BEHIND THE AFOREMENTIONED CDFNT...BRINGING A SHORT BREAK FROM THE RECENT HOT AND HUMID CONDITIONS. COOLER AND DRIER WX WILL PERSIST UNTIL THE SFC HIGH OVER IA/WI/IL SHIFTS EWD AND THE STRONG UPPER RIDGE OVER THE SWRN CONUS BUILDS INTO THE CENTRAL PLAINS. SUN THROUGH TUE...A 594+ DAM H5 PRESSURE CENTER IS FCST TO BE LOCATED OVER THE CENTER OF THE COUNTRY BY EARLY NEXT WEEK. THIS WILL BRING A RETURN OF HOT WEATHER TO THE AREA WITH LIMITED OPPORTUNITIES FOR PCPN. MODELS ARE FCSTG A BROAD AREA OF FAIRLY WEAK VORTICITY TO BREAK OFF FROM THE ERN CONUS TROF AND THEN MOVE WWD ACROSS THE SRN CONUS ON THE SOUTH SIDE OF THE HIGH. DEPENDING ON THE DETAILS...THIS FEATURE COULD PROVIDE JUST ENOUGH SUPPORT FOR ISO-SCT PCPN ACROSS THE SRN CWA. AS HAS BEEN THE CASE FOR THE LAST SEVERAL DAYS...MODELS CONTINUE TO SHOW A CLOSED LOW DVLPG SOMEWHERE ALONG THE APPALACHIANS...BUT THERE HAS BEEN LITTLE RUN TO RUN CONSISTENCY SO FAR. KANOFSKY && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 658 AM CDT WED JUL 10 2013 COVERAGE OF ELEVATED CONVECTION HAS RAPIDLY INCREASED OVER THE LAST FEW HOURS...BUT STILL EXPECTING THIS ACTIVITY TO SHIFT TO THE SE DURING THE MORNING. APPROXIMATE BACK EDGE OF THE PRECIP IS NEAR A BOONEVILLE...UIN LINE...SO WHILE COU WILL BE OUT OF THE THUNDER THREAT SHORTLY STL AREA TAFS WILL REMAIN WITH TEMPOS FOR TSRA UNTIL LATE MORNING. PREVAILING CONDITIONS WILL BE VFR CIGS AOA 5KFT...BUT WITH THE HIT AND MISS STRONG CORES VSBYS WILL CERTAINLY DROP TO IFR...WITH CIGS AT LEAST DIPPING INTO THE MVFR RANGE. WILL BE WATCHING RADAR TRENDS TO DETERMINE IF AMENDMENTS WILL BE NECESSARY FOR THESE LOWER CONDITIONS. STILL UNCERTAIN HOW ANY ADDITIONAL ACTIVITY WILL EVOLVE BY THIS AFTERNOON...BUT IN SPITE OF WEAKENING CONVERGENCE ALONG FRONT AND WITH BOUNDARY FROM THIS MORNINGS ACTIVITY SETTING UP S OF OUR CWA...THINK THAT REDEVELOPMENT MAY STILL OCCUR NEAR THE SYNOPTIC FRONT DUE TO RESIDUAL INSTABILITY AND WEAK UPPER LEVEL DYNAMICS DIPPING INTO THE AREA. SO...FOLLOWING THE LEAD OF THE LATEST HRRR DATA WILL REINTRODUCE VCTS IN STL FOR A BRIEF PERIOD EARLY THIS AFTERNOON...BEFORE FROPA PUSHES ACTIVITY S INTO SE MO/S IL. TRANQUIL CONDITIONS SHOULD PREVAIL THROUGHOUT THE AREA THIS EVENING...WITH CLEAR SKIES AND NORTH WINDS AOB 10 KTS. SPECIFICS FOR KSTL... BASED ON ABOVE REASONING WILL BE CARRYING TEMPO TSRA THROUGH 15Z WITH VFR CIGS AND MVFR VSBYS....BUT AS MENTIONED WILL BE WATCHING RADAR TRENDS TO DETERMINE IF MORE INTENSE CORES WILL IMPACT THE TERMINAL AREA. PRECIP THREAT SHOULD BRIEFLY LULL BEFORE REINTRODUCTION OF TSRA AS FRONTAL BOUNDARY MOVES THROUGH IN THE 18-20Z TIME FRAME...BUT AFTER 20Z FRONT SHOULD BE FAR ENOUGH SOUTH THAT THREAT WILL END. LATE AFTERNOON AND INTO THE EVENING SHOULD GENERALLY BE CLEAR/VFR...WITH LIGHT NORTH WINDS 5-10KTS. TRUETT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1253 PM CDT WED JUL 10 2013 .SYNOPSIS... ISSUED AT 313 AM CDT WED JUL 10 2013 THE 07Z MSL ANALYSIS SHOWED TWO MAIN BOUNDARIES ACROSS THE PLAINS. ONE WAS THE SURFACE FRONT FROM A LOW IN SOUTHEAST COLORADO ACROSS OKLAHOMA TO SOUTHWEST MISSOURI. THE OTHER WAS A TROUGH WITH ITS PRESENCE BETRAYED BY WIND FIELDS ACROSS SOUTHWEST NEBRASKA. SATELLITE DERIVED PRODUCT IMAGERY...WHERE IT WAS NOT POLLUTED WITH CLOUD...SHOWED AN AXIS OF MAXIMUM PRECIPITABLE WATER AND INSTABILITY FROM EAST CENTRAL WYOMING ACROSS THE NEBRASKA PANHANDLE AND SOUTHWEST NEBRASKA TO SOUTHEAST NEBRASKA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT WED JUL 10 2013 ONCE AGAIN...THE LOCATIONS OF CONVECTIVE DEVELOPMENT WILL DEPEND ON THE LOCATIONS OF THE FRONT AND OTHER BOUNDARIES FROM CONVECTION OVERNIGHT. IT IS DIFFICULT TO FIND ANY CONSENSUS AMONG THE AVAILABLE MODELS WITH THE SHORT RANGE FORECAST. THE RAP13 AND HRRR SEEM TO BE ON THE SAME PAGE WITH CONVECTION DEVELOPING FAIRLY EARLY TODAY IN WESTERN NEBRASKA. THE GEM REGIONAL AND THE GFS SEEM TO FAVOR THIS EVENING AND LATE NIGHT FOR THE TIMING. AS WAS THE CASE YESTERDAY...THE LOCATION OF BOUNDARIES AND THE FRONT IS A LITTLE UP IN THE AIR. AT FIRST...CENTRAL AND SOUTHWEST NEBRASKA APPEARS TO BE THE LOCATION TO WATCH WHERE THERE WAS CONVECTION YESTERDAY EVENING. LOOKING AT THE RAP13 CONVECTIVE PARAMETERS...THE SURFACE-BASED CONVECTIVE INHIBITION APPROACHES ZERO J/KG BY LATE MORNING TO EARLY AFTERNOON IN THE SOUTHWEST. ALSO...CONVECTIVE POTENTIAL ENERGY OF 1500-2500J/KG AND SFC-6KM BULK SHEAR INCREASING TO 40-50KT COULD SUPPORT LARGE HAIL. FOR LATER PERIODS...THE FRONT LIFTING ONTO THE HIGH PLAINS WOULD BE A GOOD FOCUS FOR CONVECTION TO DEVELOP THIS EVENING OR OVERNIGHT AS IT MOVES INTO WESTERN NEBRASKA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 313 AM CDT WED JUL 10 2013 THE EXPANSIVE RIDGE OF HIGH PRESSURE THAT HAS BEEN ANCHORED ACROSS THE FOUR CORNERS REGION FOR DAYS...WILL BUILD NORTH OVER OUR AREA THURSDAY INTO FRIDAY. THIS WILL BRING WARMING TEMPERATURES ALOFT...WHICH WILL CAP THE ATMOSPHERE...AND LITTLE IN THE WAY OF T-STORM ACTIVITY IS EXPECTED. IT WILL BE QUITE HOT AS WELL...WITH HIGHS IN THE 90S TO AROUND 100 DEGREES. HUMIDITY WILL REMAIN AS WELL...ESPECIALLY EAST OF HIGHWAY 83...AND A HEAT ADVISORY MAY BE NEEDED FRIDAY AND POSSIBLE SATURDAY. BY LATER SATURDAY INTO SUNDAY...A SHORTWAVE WILL SKIRT ACROSS CANADA. THIS WILL DRIVE A COLD FRONT SOUTH INTO THE REGION...WITH RETURNING CHANCES FOR T-STORMS WITH THE ARRIVAL OF THE FRONT. THE UPPER LEVEL HIGH WILL ALSO BE TEMPORALLY SUPPRESSED SOUTH...WITH TEMPERATURES COOLING JUST A FEW DEGREES. THE RIDGE IS FORECASTED TO BUILD OVERHEAD AGAIN BY TUESDAY INTO WEDNESDAY...WITH HOT WEATHER CONTINUE AND ONLY AN ISOLATED T-STORM AT BEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1253 PM CDT WED JUL 10 2013 THE KLNX WSR-88D IS CURRENTLY INTERROGATING TWO AREAS OF CONVECTIVE RAINFALL...THE FIRST ACROSS SOUTHWEST NEBRASKA...JUST WEST OF THE KLBF TERMINAL...AND THE SECOND MORE ISOLATED...BUT CONTINUING TO ADVANCE EAST/SOUTHEAST FROM THE BADLANDS REGION OF SOUTH DAKOTA...ON TRACK TO PASS OVER THE KVTN TERMINAL THIS AFTERNOON. THUS INTRODUCED -SHRA AND/OR -TSRA TO THE TAF FORECAST FOR THIS AFTERNOON AT BOTH THE KVTN AND KLBF TERMINALS. NEAR TERM GUIDANCE HAS STRUGGLED THUS FAR WITH THE WITH THE ONGOING STORMS...AS AREAL COVERAGE AND TIMING OF THE CONVECTION IS ALL OVER THE PLACE. BECAUSE OF THIS...FORECAST CONFIDENCE IS LOWER THAN USUAL. LATER TODAY/TONIGHT...ADDITIONAL STORM DEVELOPMENT IS POSSIBLE ACROSS THE HIGHER TERRAIN OF EASTERN COLORADO/WYOMING AND ACROSS NORTH CENTRAL NEBRASKA OVERNIGHT. UNCERTAINTY REMAINS HOWEVER AS TO HOW FAR EAST/SOUTH THIS ACTIVITY WILL LAST...SO FOR NOW WILL LEAVE THE FORECAST DRY FOR THE HOURS BEYOND MID-AFTERNOON AT KLBF AND KVTN AS POP CHANCES REMAIN LESS THAN 30 PERCENT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SPRINGER SHORT TERM...SPRINGER LONG TERM...TAYLOR AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
454 PM EDT WED JUL 10 2013 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL SWEEP ACROSS THE REGION THIS EVENING AS A COLD FRONT MOVES ACROSS THE REGION. SOME OF THESE STORMS COULD BE SEVERE. FOLLOWING THE PASSAGE OF THE COLD FRONT EXPECT COOLER AND LESS HUMID CONDITIONS THAN WHAT WE HAVE SEEN THIS PAST WEEK WITH AN ISOLATED SHOWER POSSIBLE THURSDAY AFTERNOON. HIGH PRESSURE WILL BUILD OVER OUR AREA BEHIND THE FRONT THURSDAY NIGHT THROUGH THE BEGINNING OF NEXT WEEK WITH DRY WEATHER. && .NEAR TERM /THROUGH THURSDAY/... SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 10PM FOR WESTERN NEW YORK. A VIGOROUS NEGATIVELY TILTING TROUGH WITH EMBEDDED 60 KT MID LEVEL JET IS LOCATED ALOFT WITH AXIS OVER LAKE HURON THIS AFTERNOON. LOW PRESSURE AT THE SURFACE IS CENTERED OVER WEST CENTRAL QUEBEC WITH A COLD FRONT EXTENDING SOUTH OF THE LOW TO JUST NORTH OF TORONTO THEN SOUTHWEST ACROSS LOWER ONTARIO PROVINCE TO NEAR DETROIT MICHIGAN. TWO FOCUS AREAS FOR STORMS AHEAD OF AND ALONG THE COLD FRONT ARE SEEN ON RADAR. ONE LARGE CLUSTER WHICH IS MERGING INTO A LINE IS FOUND FROM CHAUTAUQUA COUNTY SOUTHWEST ACROSS OHIO TO CENTRAL KENTUCKY. A SECOND AREA OF STORMS WHICH IS ORIENTED ALONG THE COLD FRONT IS ADVANCING ACROSS SOUTHERN ONTARIO PROVINCE TO THE NORTH OF LAKE ERIE. WESTERN AND NORTH CENTRAL NEW YORK LIES WITHIN THE WARM SECTOR OF THE SURFACE LOW WITH DEWPOINTS IN THE LOW 70 AND GUSTY SOUTHWEST WINDS. VISIBLE SATELLITE IMAGERY SHOWS AN EXTENSIVE CUMULUS FILED HAS DEVELOPED OVER THE GENESEE VALLEY AND FINGER LAKES WITH SOME OVERCAST ASSOCIATED WITH CONVECTIVE DEBRIS NOW WORKING OVER FAR WESTERN NEW YORK. BREAKS IN THE OVERCAST ARE ALSO WORKING IN ALONG THE I-81 CORRIDOR WITH THICK CLOUD COVER TO THE EAST. THE BREAKS IN THE CLOUD COVER ARE ALLOWING FOR CONDITIONS TO BECOME MORE UNSTABLE SPC MESOANALYSIS SHOWS UP TO 2500 J/KG CAPE ACROSS INTERIOR SECTIONS OF WESTERN NEW YORK BUT THE LAKES ARE KEEPING MUCH OF THE LAKESHORE AREAS CAPPED. AS THE COLD FRONT APPROACHES OUR REGION LATER THIS SHOWERS AND THUNDERSTORMS WILL ALSO ADVANCE EASTWARD. MODEL GUIDANCE AND CURRENT OBSERVATIONS SHOW THE BEST PROBABILITY FOR STORMS WILL BE ACROSS THE SOUTHERN TIER COUNTIES AND INLAND SECTIONS OF WESTERN NY AWAY FROM THE LAKES THIS AFTERNOON AND EVENING WITH CHANCES INCREASING FOR THE EASTERN LAKE ONTARIO REGION AFTER 00Z. RAP MODEL BUFKIT SOUNDING SHOW THAT STORM TOPS MAY EXTEND TO 35-40 KFT WHICH MATCHES UP WELL WITH KBUF ENHANCED ECHO TOPS PRODUCT. A FEW OF THE STRONGER CELLS ARE EXHIBITING TOPS TO 50+KFT OVER OHIO AND PA. THE MAIN THREATS FROM THESE STORMS WITH SUFFICIENT CAPE AVAILABLE WITHIN THE HAIL GROWTH ZONE IS FOR LARGE HAIL AND UNIDIRECTIONAL VERTICAL WIND SHEAR UP TO 50 KNOTS WOULD ALSO ALLOW FOR DAMAGING WINDS WITHIN ANY LINE SEGMENTS AND LARGER CELLS. LOCALIZED HEAVY RAIN IS ALSO A THREAT WITH THESE STORMS AS PWATS WILL RUN UP TO 2 INCHES AHEAD OF THE FRONT. AFTER SUNSET...THE FRONT SHOULD BEGIN TO MAKE A GOOD PROGRESS EASTWARD ACROSS WESTERN NEW YORK...WITH GRADUAL CLEARING BEHIND THE COLD FRONT. THE MOST NOTABLE CLEARING WILL BE ALONG THE LAKE SHORE COUNTIES TOWARD MORNING. A WEST TO NORTHWEST UPSLOPE FLOW MAY KEEP SOME CLOUDS OVER THE INLAND LOCATIONS FOR MUCH OF THE NIGHT. DESPITE THE FRONT SWEEPING THROUGH TEMPERATURES OVERNIGHT WILL REMAIN MILD AS THE DRIER AIR WILL TAKE SOME TIME TO MIX ACROSS OUR REGION. LOWS WILL RUN IN THE LOWER 60S. ON THURSDAY THE AXIS OF THE UPPER LEVEL TROUGH WILL CROSS OVER WESTERN AND CENTRAL NEW YORK WITH THE COLD FRONT FOUND ACROSS EASTERN NEW YORK SOUTH TO THE MID-ATLANTIC REGION. WHILE THE ATMOSPHERE WILL BE IN A MUCH DRIER STATE BEHIND THE FRONT THERE IS A LOW CHANCE OF SOME ISOLATED SHOWERS DEVELOPING DURING THE AFTERNOON ASSOCIATED WITH THE SYNOPTIC LIFT OF THE TROUGH AS IT SWEEPS EASTWARD. THIS MOISTURE WOULD BE FOUND MAINLY IN THE 700-900MB LAYER WITH NAM PROFILES SHOWING A CAP ABOVE THIS LEVEL. THIS CAP WOULD KEEP A LID ON ANY ACTIVITY THAT MAY DEVELOP PREVENTING THUNDERSTORMS. TEMPERATURES WILL BE VERY COMFORTABLE FOR THE FIRST TIME IN MORE THAN A WEEK WITH HIGHS MAXING OUT IN THE 70S. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... AN UPPER LEVEL TROF WILL SLOWLY MOVE ACROSS THE REGION ON THURSDAY NIGHT. THERE MAY BE A FEW LINGERING SHOWERS DUE TO LEFT OVER DAYTIME INSTABILITY ON THURSDAY EVENING. LATER IN THE NIGHT...SHOWERS MAY LINGER A BIT LONGER SOUTHEAST OF LAKE ONTARIO...WHERE THE EXITING TROF AND THE NOT-SO COLD LAKE WATERS MAY ACTUALLY ENHANCE CHANCES A BIT. NAM/GFS BUFKIT FORECAST SOUNDING SHOWS A MODEST CAP AT 10K FEET...WHICH SHOULD KEEP ANY SHOWERS ON THE LIGHT SIDE. THIS COOLER AIRMASS WILL ALLOW TEMPS TO DROP INTO THE UPPER 50S TO LOWER 60S IN MOST LOCATIONS...WITH MID 50S IN THE COOLER SPOTS OF THE SOUTHERN TIER AND EAST OF LAKE ONTARIO. BY FRIDAY...SURFACE HIGH PRESSURE WILL BE ACROSS EASTERN MICHIGAN. MODEL GUIDANCE DIFFERS ON THE HANDLING OF A CUT-OFF UPPER LOW...WITH GUIDANCE DIFFERING ON WHERE THIS SUBTLE FEATURE WILL BE. FOR THE MOST PART...A BROAD MODEL CONSENSUS PUTS THE UPPER LEVEL TROF AXIS OR CUT OFF LOW ACROSS EASTERN NEW YORK...WITH THE SREF PROBABLY THE BEST REPRESENTATION OF THIS. HAVE HIGH CONFIDENCE IN A DRY FORECAST ON FRIDAY ROCHESTER WESTWARD...WITH ONLY A MARGINAL CHANCE FOR ANY SHOWERS IN EASTERN PORTIONS OF THE CWA BASED ON WHERE THE UPPER TROF IS. EXPECT A FAIR AMOUNT OF SUNSHINE ON THE BACK OF THE EXITING TROF...WITH A NORTHERLY FLOW OFF THE LAKES LIKELY TO KEEP TEMPERATURES COOLER NEAR THE LAKES SOUTH SHORES. INLAND OF THIS...EXPECT HIGHS IN THE UPPER 70S. THE TROF AXIS SHOULD SLIDE EVER SO SLOWLY TO THE EAST INTO NEW ENGLAND ON FRIDAY NIGHT...WITH SOME MODELS STILL KEEPING THE LOW ACROSS EASTERN NEW YORK. EITHER OF THESE SCENARIOS WOULD KEEP OUR REGION DRY OVERNIGHT. FRIDAY NIGHT WILL BE THE COOLEST NIGHT OF THE STRETCH AS HIGH PRESSURE REMAINS CENTERED JUST TO OUR WEST...ALLOWING FOR LIGHT WINDS AND MAINLY CLEAR SKIES FOR GOOD RADIATIONAL COOLING. EXPECT LOWS IN THE 50S...COOLEST ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND THE NORTH COUNTRY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... THE WEATHER FOR THIS UPCOMING WEEKEND STILL LOOKS QUITE NICE...WITH FAIR WEATHER AND SEASONABLY WARM MID-SUMMER TEMPERATURES. THERE STILL WILL BE A SUBTLE CUT-OFF LOW TO CONTEND WITH...BUT THE MAJORITY OF LONG-RANGE GUIDANCE KEEPS THIS FEATURE ACROSS NEW ENGLAND FOR THE WEEKEND...WHICH WOULD KEEP US ON THE DRY BACKSIDE OF THIS LOW. EVEN IF MODEL GUIDANCE IS WRONG...A POSITION FURTHER TO THE WEST WOULD ONLY BRING MARGINAL CHANCES FOR DIURNALLY DRIVEN SHOWERS...AND DAYTIME HIGHS A FEW DEGREES COOLER THAN THE GOING FORECAST. SUNDAY SHOULD BE THE WARMER OF THE TWO DAYS...WITH HIGHS IN THE MID TO UPPER 80S...A TAD COOLER ALONG THE IMMEDIATE LAKESHORE. FOR THE FIRST HALF OF NEXT WEEK...LARGE SCALE RIDGING IS FORECAST TO BUILD ACROSS NEARLY THE ENTIRE CONUS...PUSHING THE JET STREAM UP INTO CANADA. THE STALLED UPPER LOW WILL CONTINUE TO BE IN OUR GENERAL VICINITY...UNTIL IT FINALLY SPINS ITSELF OUT BY MID-WEEK. THIS LOW MAY BE ENOUGH TO GENERATE A FEW SHOWERS...BUT THESE SHOULD BE SO SPARSE THAT WE WILL ONLY CARRY SLIGHT CHANCE POPS AWAY FROM THE LAKES. MEAN 850 MB TEMPERATURES SHOULD RUN ABOUT +16C...WITH THE GFS/GGEM AVERAGING A TAD WARMER THAN THE EUROPEAN MODEL GUIDANCE. USING A BLEND...EXPECT DAYTIME HIGHS TO CONTINUE TO BE ON THE WARM SIDE. INTERIOR LOCATIONS SHOULD TOP OUT IN THE UPPER 80S TO AROUND 90...WITH LOWER TO MID 80S ALONG THE IMMEDIATE LAKE SHORES. HUMIDITY WILL BEGIN TO INCREASE AS WELL...BUT NOT AS HIGH AS WE HAVE SEEN THE PAST 10 DAYS. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... STRONG TO SEVERE THUNDERSTORMS WILL WORK ACROSS WESTERN NEW YORK AHEAD OF A COLD FRONT THIS EVENING. THE STRONGEST CELLS MAY CONTAIN HAIL TO 1.5 INCHES AND WIND GUSTS TO 60 KNOTS. EXPECT SHRA/TSRA TO ALSO IMPACT KART BUT NOT TIL AFTER 00Z AND LOWER CHANCE FOR SEVERE CHARACTERISTICS. ONCE THE FRONT MOVES THROUGH BETWEEN 03-06Z...EXPECT IMPROVING WEATHER ACROSS ALL AREAS WITH RESIDUAL UPSLOPE CLOUDS INLAND...BUT WITH VFR CONDITIONS. OUTLOOK... THURSDAY...MAINLY VFR. A CHANCE OF SHOWERS. FRIDAY THROUGH SUNDAY...VFR. && .MARINE... BREEZY SOUTHWEST WINDS ARE OBSERVED ON THE LAKES THIS EVENING AHEAD OF A COLD FRONT. SHOWERS AND THUNDERSTORMS WILL SWEEP ACROSS THE REGION THROUGH THE EVENING WITH POSSIBLE LARGE HAIL AND STRONG WIND GUSTS. SMALL CRAFT ADVISORIES ARE IN EFFECT AS OUTLINED BELOW DUE TO HIGHER WINDS AND WAVES OBSERVED AHEAD OF THE FRONT. FOLLOWING THE FRONT...EXPECT HIGH PRESSURE BUILDING IN THURSDAY...LASTING WELL INTO THE UPCOMING WEEKEND WITH LIGHT WINDS AND LITTLE WAVE ACTION. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EDT THURSDAY FOR LEZ020-040- 041. SMALL CRAFT ADVISORY UNTIL 7 AM EDT THURSDAY FOR LOZ043>045. && $$ SYNOPSIS.../SMITH NEAR TERM...SMITH SHORT TERM...APFFEL LONG TERM...APFFEL AVIATION...SMITH MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
354 PM EDT WED JUL 10 2013 .SYNOPSIS... WATCH FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS MUCH OF THE NORTH COUNTRY THIS AFTERNOON AND EVENING. ANY STORMS WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AND VERY HEAVY RAINFALL THAT COULD LEAD TO FLASH FLOODING. THUS A FLASH FLOOD WATCH REMAINS IN EFFECT THIS AFTERNOON THROUGH MIDNIGHT. THE THREAT FOR PRECIPITATION WILL BE LIMITED TO EASTERN VERMONT ON THURSDAY AND THEN DRY WEATHER WITH SEASONAL TEMPERATURES IS EXPECTED FOR THE WEEKEND. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 1009 AM EDT WEDNESDAY...UPDATE TO POPS THROUGH THE DAY BASED OFF CURRENT RADAR ACTIVITY AND BLEND OF AVAILABLE CAM MODEL OUTPUT. STILL LOOKING MORE OR LESS AT 40/70% POPS ACROSS THE AREA TODAY...BUT DETAILED CURRENT BAND PROGRESSING EAST ACROSS CENTRAL NY MOVING INTO THE AREA A TAD BETTER AND AS RESOLVED QUITE WELL BY LATEST HRRR DATA. REST OF FORECAST REMAINS MORE OR LESS IN GOOD SHAPE. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS... GOING FORECAST IN GOOD SHAPE AND NO CHANGES NEEDED AT THIS TIME. THREAT FOR FLASH FLOODING AND STRONG GUSTY WINDS WILL REMAIN ACROSS MUCH OF THE AREA THIS AFTERNOON AND EVENING. COMPOSITE ANALYSIS SHOWS STRONGEST DYNAMIC SUPPORT AND DEEP LAYER SHEAR WILL REMAIN ACROSS EASTERN CANADA THIS AFTERNOON AND EVENING AS LARGE UPPER TROUGH MOVES INTO THE AREA. LATER THIS AFTERNOON HOWEVER...THE SOUTHERN END OF THE STRONGER FLOW ALOFT...25 KNOTS AT 850 MB AND 30 KNOTS AT 500 MB WILL MOVE ACROSS THE SOUTHERN HALF OF VERMONT THIS AFTERNOON. THIS COMBINED WITH CONVECTIVE AVAILABLE POTENTIAL ENERGY APPROACHING 1000 J/KG SUGGEST SOME ORGANIZATION TO THE STORMS WILL EXIST. THUS LOOKING AT PULSE/MULTICELL STORMS LATER THIS AFTERNOON AND EVENING WITH THE AREA FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY AS THE MAIN AREA OF CONCERN. AXIS OF HIGH PRECIPITABLE WATER AIR...VALUES AROUND 2 INCHES...WILL NOSE RIGHT UP INTO THE AREA. SO WITH STORM MOTIONS UNDER 15 KNOTS...THE THREAT FOR HEAVY DOWNPOURS AND FLASH FLOODING WILL EXIST ESPECIALLY SINCE THE AREA COVERAGE OF STORMS WILL BE GREATER THAN THE PAST COUPLE OF DAYS. THUS GOING IDEA OF A FLASH FLOOD WATCH FOR MOST OF THE AREA STILL LOOKS GOOD. IN ADDITION...FEEL WITH SOME ORGANIZATION TO THE STORMS...THREAT FOR STRONG GUSTY WINDS WILL EXIST. HAVE INCLUDED THE ENHANCED WORDING IN THE FORECAST FOR THESE TWO THREATS. WE MAY SEE CLOUDS AND SPOTTY SHOWERS MOVE ACROSS THE AREA THIS MORNING...BUT MAIN THREAT FOR STORMS WILL BE AFTER 200 PM. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY NIGHT/... AS OF 437 AM EDT WEDNESDAY...ACTIVE WEATHER WITH STORMS POTENTIALLY PRODUCING FLASH FLOODING WILL EXIST THROUGH MIDNIGHT TONIGHT...THEN INTENSITY OF STORMS WILL WEAKEN OVERNIGHT AND MOVE EAST OF THE AREA. COLD FRONT WILL BECOME PARALLEL TO THE UPPER FLOW ON THURSDAY AND THUS THE FRONT WILL STILL HANG AROUND EASTERN VERMONT FOR A CONTINUED CHANCE OF SHOWERS OR STORMS. HIGH PRESSURE BUILDS IN LATE THURSDAY NIGHT AND FRIDAY FOR DRIER WEATHER AND TEMPERATURES TRENDING SLIGHTLY BELOW NORMAL BY FRIDAY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 353 PM EDT WEDNESDAY...HIGH PRESSURE OVER THE GREAT LAKES WILL PERSIST THROUGH THE WEEKEND WITH AN INVERTED TROUGH DEVELOPING OFF THE NORTHEAST COAST. ECMWF AND GFS DEVELOP UPPER LEVEL TROUGH ASSOCIATED WITH INVERTED TROUGH INTO CLOSED LOW...PSBLY CREATING SLGT TO LOW CHC FOR PRECIP. AT THE SFC...HIGH PRESSURE PERSISTS WHICH WILL AID IN KEEPING THE AREA DRY. ECMWF THEN BUILDS RIDGE OF HIGH PRESSURE OVER NORTHEAST PUSHING THE CLOSED LOW WESTWARD. STILL LOTS OF UNCERTAINTY THAT FAR OUT. HAVE LEANED TOWARD DRIER ECMWF SOLUTION THROUGH EARLY NEXT WEEK. WARM AIR WILL LEAD TO MAX TEMPS IN THE U70S-M80S AND MIN TEMPS GENERALLY IN THE 60S. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... THROUGH 18Z THURSDAY...ACTIVE AVIATION FORECAST FOR THIS TAF ISSUANCE. CURRENT FLIGHT CATEGORIES RANGE FROM VFR TO MVFR. PRE- FRONTAL LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS EXTENDING DOWN THE CHAMPLAIN TO THE HUDSON VALLEYS WILL CONTINUE TO PUSH EASTWARD OVER THE NEXT HOUR OR SO PRODUCING TEMPO MVFR/IFR VISIBILITIES. THINK THE BEST CHANCE AT SEEING ANY THUNDER OUT OF THIS INITIAL ACTIVITY IS AT RUT WHERE BETTER INSTABILITY EXISTS. RE- DEVELOPMENT IS EXPECTED ONCE THE INITIAL SHOWERS CLEAR OUT TIED TO THE COLD FRONT ITSELF...SOME OF WHICH COULD BE STRONG WITH GUSTY WINDS AND POTENTIAL LLWS/TURBULENCE. HAVE TREATED WITH VCSH AND CB FOR ALL TAFS EXCEPT MPV TO COVER THIS POTENTIAL MAINLY AFTER 21Z. FRONT SWEEPS EAST LATE TONIGHT/OVERNIGHT WITH SHARP WIND SHIFT TO NORTHWEST WITH DECREASE IN SHOWERS/STORMS. THE EXCEPTION IS AT MPV AND RUT WHERE THE FRONT MAY SLOW. THINK THE BEST CHANCE AT FOG OVERNIGHT WOULD BE AT SLK AND MSS. SHOWERS LINGER INTO THE MORNING HOURS ESPECIALLY AT RUT AND MPV BUT IMPROVING CONDITIONS FOR THE REST OF THE TAFS. WINDS THURSDAY WILL TEND LIGHT WESTERLY. OUTLOOK 18Z THURSDAY THROUGH SUNDAY... 18Z THURSDAY THRU 12Z FRIDAY...FRONT SLOWLY SHIFTS SOUTH WITH SHOWERS ENDING AT MPV AND RUT. MAINLY VFR EXCEPT IFR/LIFR IN MIST/FOG OVERNIGHT. 12Z FRIDAY THRU SUNDAY...MAINLY VFR EXCEPT MVFR IN PERIODS OF SHOWERS MAINLY ACROSS RUT WITH SLOW-MOVING FRONTAL BOUNDARY. OVERNIGHT FOG/MIST POTENTIAL 06-12Z TIMEFRAME ESPECIALLY AT SLK AND MPV. && .HYDROLOGY... AS OF 437 AM EDT WEDNESDAY...ONCE AGAIN WE SAW ISOLATED STORMS PRODUCE FLASH FLOODING ON TUESDAY. CONDITIONS FOR MORE FLASH FLOODING WILL EXIST THIS AFTERNOON AND EVENING AND THE POTENTIAL FOR FLASH FLOODING MAY ACTUALLY BE GREATER SIMPLY FOR THE FACT THAT THERE WILL BE MORE STORMS AROUND THAN THE PAST COUPLE OF DAYS. EXPECT SCATTERED TO NUMEROUS THUNDERSTORMS DEVELOPING OVER THE AREA THIS AFTERNOON...ESPECIALLY FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY. THE DEEP LAYER OF MOISTURE IN THE ATMOSPHERE OVER THE REGION COMBINED WITH SLOW MOVING STORMS SUGGESTS FLASH FLOODING IS POSSIBLE. THUS WILL KEEP THE FLASH FLOOD WATCH IN PLACE. POTENTIAL IMPACTS INCLUDE WASHED OUT AND FLOODED ROADS...FIELD FLOODING...RAPID RISES ON SMALLER RIVERS AND STREAMS. && .MARINE... AS OF 436 AM EDT WEDNESDAY...ACTIVE WEATHER IS EXPECTED ACROSS LAKE CHAMPLAIN TODAY THROUGH THIS EVENING. FIRST EXPECT STRONGER WINDS OVER THE LAKE WITH SOUTH WINDS INCREASING INTO THE 20 TO 30 KNOT RANGE BY AFTERNOON AND NOT DECREASING UNTIL AFTER MIDNIGHT TONIGHT. THESE WINDS ARE STRONGER THAN WHAT HAS BEEN FELT OVER THE LAKE THE PAST FEW DAYS. THUS A LAKE WIND ADVISORY IS IN EFFECT. IN ADDITION...EXPECT THUNDERSTORMS TO DEVELOP OVER NORTHERN NEW YORK THIS AFTERNOON AND MOVE EAST ACROSS LAKE CHAMPLAIN. BE AWARE THAT ANY STORMS WILL HAVE THE POTENTIAL TO PRODUCE STRONG GUSTY WINDS AND AS WE HAVE SEEN THE PAST MONTH OR SO...VERY HEAVY DOWNPOURS. && .EQUIPMENT... AS OF 436 AM EDT WEDNESDAY...THE KTYX RADAR IS DOWN UNTIL FURTHER NOTICE. TECHS HAVE ORDERED PARTS...THOUGH RETURN TO SERVICE IS UNKNOWN AT THIS TIME. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VTZ001>012- 016>019. NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ028>031- 034-035. && $$ SYNOPSIS...EVENSON NEAR TERM...EVENSON/JMG SHORT TERM...EVENSON LONG TERM...KGM/NEILES AVIATION...NEILES/LOCONTO HYDROLOGY... MARINE... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
126 PM EDT WED JUL 10 2013 .SYNOPSIS... WATCH FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS MUCH OF THE NORTH COUNTRY THIS AFTERNOON AND EVENING. ANY STORMS WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AND VERY HEAVY RAINFALL THAT COULD LEAD TO FLASH FLOODING. THUS A FLASH FLOOD WATCH REMAINS IN EFFECT THIS AFTERNOON THROUGH MIDNIGHT. THE THREAT FOR PRECIPITATION WILL BE LIMITED TO EASTERN VERMONT ON THURSDAY AND THEN DRY WEATHER WITH SEASONAL TEMPERATURES IS EXPECTED FOR THE WEEKEND. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 1009 AM EDT WEDNESDAY...UPDATE TO POPS THROUGH THE DAY BASED OFF CURRENT RADAR ACTIVITY AND BLEND OF AVAILABLE CAM MODEL OUTPUT. STILL LOOKING MORE OR LESS AT 40/70% POPS ACROSS THE AREA TODAY...BUT DETAILED CURRENT BAND PROGRESSING EAST ACROSS CENTRAL NY MOVING INTO THE AREA A TAD BETTER AND AS RESOLVED QUITE WELL BY LATEST HRRR DATA. REST OF FORECAST REMAINS MORE OR LESS IN GOOD SHAPE. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS... GOING FORECAST IN GOOD SHAPE AND NO CHANGES NEEDED AT THIS TIME. THREAT FOR FLASH FLOODING AND STRONG GUSTY WINDS WILL REMAIN ACROSS MUCH OF THE AREA THIS AFTERNOON AND EVENING. COMPOSITE ANALYSIS SHOWS STRONGEST DYNAMIC SUPPORT AND DEEP LAYER SHEAR WILL REMAIN ACROSS EASTERN CANADA THIS AFTERNOON AND EVENING AS LARGE UPPER TROUGH MOVES INTO THE AREA. LATER THIS AFTERNOON HOWEVER...THE SOUTHERN END OF THE STRONGER FLOW ALOFT...25 KNOTS AT 850 MB AND 30 KNOTS AT 500 MB WILL MOVE ACROSS THE SOUTHERN HALF OF VERMONT THIS AFTERNOON. THIS COMBINED WITH CONVECTIVE AVAILABLE POTENTIAL ENERGY APPROACHING 1000 J/KG SUGGEST SOME ORGANIZATION TO THE STORMS WILL EXIST. THUS LOOKING AT PULSE/MULTICELL STORMS LATER THIS AFTERNOON AND EVENING WITH THE AREA FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY AS THE MAIN AREA OF CONCERN. AXIS OF HIGH PRECIPITABLE WATER AIR...VALUES AROUND 2 INCHES...WILL NOSE RIGHT UP INTO THE AREA. SO WITH STORM MOTIONS UNDER 15 KNOTS...THE THREAT FOR HEAVY DOWNPOURS AND FLASH FLOODING WILL EXIST ESPECIALLY SINCE THE AREA COVERAGE OF STORMS WILL BE GREATER THAN THE PAST COUPLE OF DAYS. THUS GOING IDEA OF A FLASH FLOOD WATCH FOR MOST OF THE AREA STILL LOOKS GOOD. IN ADDITION...FEEL WITH SOME ORGANIZATION TO THE STORMS...THREAT FOR STRONG GUSTY WINDS WILL EXIST. HAVE INCLUDED THE ENHANCED WORDING IN THE FORECAST FOR THESE TWO THREATS. WE MAY SEE CLOUDS AND SPOTTY SHOWERS MOVE ACROSS THE AREA THIS MORNING...BUT MAIN THREAT FOR STORMS WILL BE AFTER 200 PM. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... AS OF 437 AM EDT WEDNESDAY...ACTIVE WEATHER WITH STORMS POTENTIALLY PRODUCING FLASH FLOODING WILL EXIST THROUGH MIDNIGHT TONIGHT...THEN INTENSITY OF STORMS WILL WEAKEN OVERNIGHT AND MOVE EAST OF THE AREA. COLD FRONT WILL BECOME PARALLEL TO THE UPPER FLOW ON THURSDAY AND THUS THE FRONT WILL STILL HANG AROUND EASTERN VERMONT FOR A CONTINUED CHANCE OF SHOWERS OR STORMS. HIGH PRESSURE BUILDS IN LATE THURSDAY NIGHT AND FRIDAY FOR DRIER WEATHER AND TEMPERATURES TRENDING SLIGHTLY BELOW NORMAL BY FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 437 AM EDT WEDNESDAY...THE PATTERN CHANGE TO A WESTERLY FLOW OF DRIER WEATHER WILL PERSIST FRIDAY NIGHT THRU TUESDAY WITH A WARMING TREND. HIGH PRESSURE WILL PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK WITH UPPER LEVEL RIDGING AND A NW TO W FLOW ALOFT. DO NOT SEE ANY SIGNIFICANT CHANCE FOR PRECIPITATION IN THE EXTENDED. STILL LOTS OF UNCERTAINTY THAT FAR OUT...BUT GFS AND NAM BOTH HINT AT SOME SHOWERS AROUND FRIDAY NIGHT AND SATURDAY. HAVE LEANED TOWARDS DRIER ECMWF AT THIS POINT. TEMPERATURES WILL START OUT SLIGHTLY BELOW NORMAL...BUT TREND BACK OVER NORMAL TOWARDS THE END OF THE PERIOD. && .AVIATION /17Z WEDNESDAY THROUGH MONDAY/... THROUGH 18Z THURSDAY...ACTIVE AVIATION FORECAST FOR THIS TAF ISSUANCE. CURRENT FLIGHT CATEGORIES RANGE FROM VFR TO MVFR. PRE- FRONTAL LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS EXTENDING DOWN THE CHAMPLAIN TO THE HUDSON VALLEYS WILL CONTINUE TO PUSH EASTWARD OVER THE NEXT HOUR OR SO PRODUCING TEMPO MVFR/IFR VISIBILITIES. THINK THE BEST CHANCE AT SEEING ANY THUNDER OUT OF THIS INITIAL ACTIVITY IS AT RUT WHERE BETTER INSTABILITY EXISTS. RE- DEVELOPMENT IS EXPECTED ONCE THE INITIAL SHOWERS CLEAR OUT TIED TO THE COLD FRONT ITSELF...SOME OF WHICH COULD BE STRONG WITH GUSTY WINDS AND POTENTIAL LLWS/TURBULENCE. HAVE TREATED WITH VCSH AND CB FOR ALL TAFS EXCEPT MPV TO COVER THIS POTENTIAL MAINLY AFTER 21Z. FRONT SWEEPS EAST LATE TONIGHT/OVERNIGHT WITH SHARP WIND SHIFT TO NORTHWEST WITH DECREASE IN SHOWERS/STORMS. THE EXCEPTION IS AT MPV AND RUT WHERE THE FRONT MAY SLOW. THINK THE BEST CHANCE AT FOG OVERNIGHT WOULD BE AT SLK AND MSS. SHOWERS LINGER INTO THE MORNING HOURS ESPECIALLY AT RUT AND MPV BUT IMPROVING CONDITIONS FOR THE REST OF THE TAFS. WINDS THURSDAY WILL TEND LIGHT WESTERLY. OUTLOOK 18Z THURSDAY THROUGH SUNDAY... 18Z THURSDAY THRU 12Z FRIDAY...FRONT SLOWLY SHIFTS SOUTH WITH SHOWERS ENDING AT MPV AND RUT. MAINLY VFR EXCEPT IFR/LIFR IN MIST/FOG OVERNIGHT. 12Z FRIDAY THRU SUNDAY...MAINLY VFR EXCEPT MVFR IN PERIODS OF SHOWERS MAINLY ACROSS RUT WITH SLOW-MOVING FRONTAL BOUNDARY. OVERNIGHT FOG/MIST POTENTIAL 06-12Z TIMEFRAME ESPECIALLY AT SLK AND MPV. && .HYDROLOGY... AS OF 437 AM EDT WEDNESDAY...ONCE AGAIN WE SAW ISOLATED STORMS PRODUCE FLASH FLOODING ON TUESDAY. CONDITIONS FOR MORE FLASH FLOODING WILL EXIST THIS AFTERNOON AND EVENING AND THE POTENTIAL FOR FLASH FLOODING MAY ACTUALLY BE GREATER SIMPLY FOR THE FACT THAT THERE WILL BE MORE STORMS AROUND THAN THE PAST COUPLE OF DAYS. EXPECT SCATTERED TO NUMEROUS THUNDERSTORMS DEVELOPING OVER THE AREA THIS AFTERNOON...ESPECIALLY FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY. THE DEEP LAYER OF MOISTURE IN THE ATMOSPHERE OVER THE REGION COMBINED WITH SLOW MOVING STORMS SUGGESTS FLASH FLOODING IS POSSIBLE. THUS WILL KEEP THE FLASH FLOOD WATCH IN PLACE. POTENTIAL IMPACTS INCLUDE WASHED OUT AND FLOODED ROADS...FIELD FLOODING...RAPID RISES ON SMALLER RIVERS AND STREAMS. && .MARINE... AS OF 436 AM EDT WEDNESDAY...ACTIVE WEATHER IS EXPECTED ACROSS LAKE CHAMPLAIN TODAY THROUGH THIS EVENING. FIRST EXPECT STRONGER WINDS OVER THE LAKE WITH SOUTH WINDS INCREASING INTO THE 20 TO 30 KNOT RANGE BY AFTERNOON AND NOT DECREASING UNTIL AFTER MIDNIGHT TONIGHT. THESE WINDS ARE STRONGER THAN WHAT HAS BEEN FELT OVER THE LAKE THE PAST FEW DAYS. THUS A LAKE WIND ADVISORY IS IN EFFECT. IN ADDITION...EXPECT THUNDERSTORMS TO DEVELOP OVER NORTHERN NEW YORK THIS AFTERNOON AND MOVE EAST ACROSS LAKE CHAMPLAIN. BE AWARE THAT ANY STORMS WILL HAVE THE POTENTIAL TO PRODUCE STRONG GUSTY WINDS AND AS WE HAVE SEEN THE PAST MONTH OR SO...VERY HEAVY DOWNPOURS. && .EQUIPMENT... AS OF 436 AM EDT WEDNESDAY...THE KTYX RADAR IS DOWN UNTIL FURTHER NOTICE. TECHS HAVE ORDERED PARTS...THOUGH RETURN TO SERVICE IS UNKNOWN AT THIS TIME. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VTZ001>012- 016>019. NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ028>031- 034-035. && $$ SYNOPSIS...EVENSON NEAR TERM...EVENSON/JMG SHORT TERM...EVENSON LONG TERM...NEILES AVIATION...NEILES/LOCONTO HYDROLOGY... MARINE... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
225 PM EDT WED JUL 10 2013 .SYNOPSIS... A SERIES OF WEAK DISTURBANCES ALOFT WILL CROSS THE MIDDLE ATLANTIC REGION THROUGH TONIGHT. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM WEDNESDAY... ANOTHER UNSETTLED AFTERNOON AND EVENING EXPECTED ACROSS CENTRAL NC WITH A CONSIDERABLE AMOUNT OF CLOUDINESS AND A COUPLE OF FAVORED REGIONS FOR CONVECTION. MORNING UPPER AIR ANALYSIS AND SATELLITE IMAGERY DEPICTS A LINGERING SHEAR AXIS DRAPED NORTHEAST TO SOUTHWEST FROM KECG TO KGSB TO KLBT. THE RAP SUGGESTS THIS FEATURE WILL DRIFT EAST SLIGHTLY AND WOULD FAVOR CONVECTION ACROSS THE EASTERN THIRD OF THE RAH CWA. ANOTHER REGION FAVORED FOR CONVECTION WILL BE THE ACROSS THE FOOTHILLS OF NC/VA WHERE AN APPROACHING TROUGH AXIS WILL INITIATE CONVECTION THAT IS PROGGED BY MANY CONVECTION ALLOWING MODELS TO DEVELOP INTO A MORE LINEAR/MULTI-CELL SYSTEM THAT WILL LIKELY MOVE INTO WESTERN/NORTHERN PARTS OF THE RAH CWA LATE THIS AFTERNOON AND EVENING. THE AIR MASS ACROSS CENTRAL NC IS WET WITH PW VALUES AROUND 1.75 INCHES. MODERATE INSTABILITY WITH UNIMPRESSIVE LAPSE RATES IN A WEAK SOUTHWESTERLY FLOW SHOULD LIMIT THE SEVERE THREAT TO A FEW STORMS WITH DOWNBURST WINDS FROM PRECIP LOADING WITH LOCALIZED FLOODING IN SLOW MOVING STORMS A MORE NOTEWORTHY THREAT. CURRENT FORECAST OF HIGHS IN THE UPPER 80S TO AROUND 90 AND LOWS IN THE LOWER 70S LOOKS GOOD. -BLAES && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 320 AM WEDNESDAY... THE FLOW ALOFT WILL UNDERGO SIGNIFICANT AMPLIFICATION THIS PERIOD... HIGHLIGHTED FOR CENTRAL NC BY A SHARP...POSITIVELY TILTED TROUGH AXIS FROM EASTERN CANADA SSW TO THE LOWER MS VALLEY. MOIST SW FLOW ALOFT AND STRONG QG FORCING FOR ASCENT ASSOCIATED WITH THE TROUGH/UPPER JET...IN ADDITION TO THE THU NIGHT ARRIVAL OF AN ACCOMPANYING SURFACE COLD FRONT...WILL YIELD NUMEROUS TO WIDESPREAD SHOWERS AND STORMS THU AFTERNOON AND THROUGHOUT THE NIGHT... INCLUDING A PROBABLE LOOSELY-ORGANIZED LINE OF STORMS...WITH HEAVY RAIN AND A FEW STRONG WIND GUSTS...AHEAD OF/ALONG THE FRONT. A WIDESPREAD SOAKING RAIN OF ONE HALF TO ONE INCH IS LIKELY...WITH LOCALLY MUCH HIGHER AMOUNTS WHERE THE (EFFECTIVE) FRONTAL CONVECTION OVERLAPS EARLIER AFTERNOON AND EVENING WARM-SECTOR STORMS. SIMILAR TEMPERATURES TO PREVIOUS DAYS...GENERALLY UPPER 80S TO AROUND 90...AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... AS OF 150 PM WEDNESDAY... THE LONG TERM WILL BE CHARACTERIZED BY A FRONTAL ZONE CROSSING THE AREA AND STALLING IN THE VICINITY OF THE COAST BEFORE RETROGRADING BACK ACROSS OUR AREA THIS WEEKEND. AN EXTENDED PERIOD OF WET AND UNSETTLED WEATHER CAN BE EXPECTED THROUGH EARLY NEXT WEEK. CONSIDERING ALL THE ANTECEDENT RAINFALL WE HAVE HAD ACROSS CENTRAL NORTH CAROLINA...AND PRECIPITABLE WATER VALUES OVER 2 INCHES THROUGHOUT THE PERIOD...THE POTENTIAL FOR FLASH FLOODING WILL BE HIGH AND THE BIGGEST CONCERN FOR THIS FORECAST PERIOD. QPF FOR THIS PERIOD WILL MOST LIKELY BE A WIDESPREAD 1.5 TO 2 INCHES WITH SOME LOCALES EXPERIENCING HIGHER AMOUNTS IN TRAINING OR HEAVIER THUNDERSTORMS. THE FRONT WILL CROSS CENTRAL NC ON FRIDAY...DRIVEN BY A MID-ATLANTIC SURFACE LOW. THERE IS SOME UNCERTAINTY IN TIMING. THE LATEST GFS SHOWS A SLOWER PROGRESSION OF THE FRONT BUT MAY HAVE SOME ISSUES WITH SOME OF THE MESO-SCALE FEATURES THAT MAY FORM IN THE MEANTIME. THE NAM IS MUCH MORE PROGRESSIVE WITH THE FRONT BRINGING IT THROUGH THE CWA BEFORE 12Z FRIDAY WHILE THE GFS SLOWS THE FRONT AND HAS IT LINGER ACROSS THE AREA THROUGH 18Z. EITHER WAY MUCH OF THE CWA IF NOT ALL WILL BE WET WITH INCREASING CHANCES IN THE SOUTHEAST LATER IN THE DAY AS THE FRONT SETTLES OVER THE COASTAL PLAIN. THE FRONT WILL STAY SOUTHEAST OF THE AREA FOR MOST OF THE DAY ON SATURDAY BEFORE THE BERMUDA HIGH BEGINS TO SLOWLY WORK BACK TO THE WEST AND BEGIN A SLOW RETROGRADE OF THE FRONT LATE SATURDAY INTO SUNDAY MORNING. THE X FACTOR HERE WILL BE REMNANT MOISTURE ASSOCIATED CHANTAL WITH WHAT WILL MOST LIKELY BE CLASSIFIED AS A TROPICAL DEPRESSION AT THAT TIME. THIS COULD BRING MOISTURE BACK TO THE NORTH AND WEST A LITTLE QUICKER THAN THE CURRENT GFS SHOWS. TEMPERATURES DURING THIS PERIOD WILL BE IN THE MID 80S FOR HIGHS WITH LOWS IN THE UPPER 60S NORTHWEST TO LOWER 70S SOUTHEAST. ON SUNDAY SOUTHEASTERLY FLOW WILL RETURN TO THE AREA (PERHAPS LATER SUNDAY IN THE TRIAD) AND BEGIN A SLIGHT WARMING TREND WITH CONTINUED STRONG MOISTURE ADVECTION THROUGH THE DAY ON SUNDAY BEFORE BECOMING MORE EASTERLY AND SLIGHTLY LESS WET BUT PW VALUES WILL STILL HOVER AROUND 2 INCHES THROUGH TUESDAY. GRADUALLY THE HIGH IN THE WESTERN ATLANTIC WILL BUILD BACK IN AND SLOWLY HELP TO DRY THINGS OUT POSSIBLY BY WEDNESDAY. THICKNESS VALUES SUPPORT MAXIMUM TEMPERATURES FOR THIS PERIOD WILL GRADUALLY RISE FROM THE MID 80S TO NEAR 90 (AT LEAST IN THE SOUTHEAST) BY WEDNESDAY. LOWS GENERALLY IN THE UPPER 60S TO LOW 70S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 225 PM TUESDAY... LITTLE CHANGE IN THE WEATHER PATTERN DURING THE PERIOD WITH A FAIRLY TYPICAL ALTHOUGH PERHAPS MORE ACTIVE MID SUMMER WEATHER PATTERN WITH A WARM AND HUMID AIRMASS. SCT CONVECTION WILL CONTINUE TO DEVELOP THIS AFTERNOON...ESPECIALLY ACROSS THE COASTAL PLAIN AFFECTING KFAY AND KRWI. ANOTHER AREA OF CONVECTION DEVELOPING ACROSS THE MOUNTAINS WILL LIKELY MOVE ACROSS THE PIEDMONT THIS EVENING AFFECTING KINT/KGSO AND PERHAPS TOWARD THE COASTAL PLAIN LATE THIS EVENING. OUTSIDE OF THUNDERSTORMS...VFR CONDITIONS ARE ANTICIPATED THIS AFTERNOON AND EVENING. OVERNIGHT TOWARD DAYBREAK ANOTHER ROUND OF IFR/LIFR STRATUS IS LIKELY. THE REDUCED CEILINGS WILL GRADUALLY LIFT DURING THE MORNING AND BECOME VFR BEFORE NOON. ADDITIONAL CONVECTION...PERHAPS WITH EVEN GREATER COVERAGE IS LIKELY THURSDAY AFTERNOON AND EVENING. LOOKING FURTHER AHEAD...WEATHER CONDITIONS WILL LIKELY FEATURE A SIMILAR PATTERN OF SHOWERS AND THUNDERSTORMS...MOST NUMEROUS DURING THE AFTERNOON AND EVENING WITH CONSIDERABLE CLOUDS AND PERIODS OF LOW CEILINGS...ESPECIALLY IN THE EARLY MORNING. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...BLAES SHORT TERM...MWS LONG TERM...ELLIS AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
151 PM EDT WED JUL 10 2013 .SYNOPSIS... A SERIES OF WEAK DISTURBANCES ALOFT WILL CROSS THE MIDDLE ATLANTIC REGION THROUGH TONIGHT. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM WEDNESDAY... ANOTHER UNSETTLED AFTERNOON AND EVENING EXPECTED ACROSS CENTRAL NC WITH A CONSIDERABLE AMOUNT OF CLOUDINESS AND A COUPLE OF FAVORED REGIONS FOR CONVECTION. MORNING UPPER AIR ANALYSIS AND SATELLITE IMAGERY DEPICTS A LINGERING SHEAR AXIS DRAPED NORTHEAST TO SOUTHWEST FROM KECG TO KGSB TO KLBT. THE RAP SUGGESTS THIS FEATURE WILL DRIFT EAST SLIGHTLY AND WOULD FAVOR CONVECTION ACROSS THE EASTERN THIRD OF THE RAH CWA. ANOTHER REGION FAVORED FOR CONVECTION WILL BE THE ACROSS THE FOOTHILLS OF NC/VA WHERE AN APPROACHING TROUGH AXIS WILL INITIATE CONVECTION THAT IS PROGGED BY MANY CONVECTION ALLOWING MODELS TO DEVELOP INTO A MORE LINEAR/MULTI-CELL SYSTEM THAT WILL LIKELY MOVE INTO WESTERN/NORTHERN PARTS OF THE RAH CWA LATE THIS AFTERNOON AND EVENING. THE AIR MASS ACROSS CENTRAL NC IS WET WITH PW VALUES AROUND 1.75 INCHES. MODERATE INSTABILITY WITH UNIMPRESSIVE LAPSE RATES IN A WEAK SOUTHWESTERLY FLOW SHOULD LIMIT THE SEVERE THREAT TO A FEW STORMS WITH DOWNBURST WINDS FROM PRECIP LOADING WITH LOCALIZED FLOODING IN SLOW MOVING STORMS A MORE NOTEWORTHY THREAT. CURRENT FORECAST OF HIGHS IN THE UPPER 80S TO AROUND 90 AND LOWS IN THE LOWER 70S LOOKS GOOD. -BLAES && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 320 AM WEDNESDAY... THE FLOW ALOFT WILL UNDERGO SIGNIFICANT AMPLIFICATION THIS PERIOD... HIGHLIGHTED FOR CENTRAL NC BY A SHARP...POSITIVELY TILTED TROUGH AXIS FROM EASTERN CANADA SSW TO THE LOWER MS VALLEY. MOIST SW FLOW ALOFT AND STRONG QG FORCING FOR ASCENT ASSOCIATED WITH THE TROUGH/UPPER JET...IN ADDITION TO THE THU NIGHT ARRIVAL OF AN ACCOMPANYING SURFACE COLD FRONT...WILL YIELD NUMEROUS TO WIDESPREAD SHOWERS AND STORMS THU AFTERNOON AND THROUGHOUT THE NIGHT... INCLUDING A PROBABLE LOOSELY-ORGANIZED LINE OF STORMS...WITH HEAVY RAIN AND A FEW STRONG WIND GUSTS...AHEAD OF/ALONG THE FRONT. A WIDESPREAD SOAKING RAIN OF ONE HALF TO ONE INCH IS LIKELY...WITH LOCALLY MUCH HIGHER AMOUNTS WHERE THE (EFFECTIVE) FRONTAL CONVECTION OVERLAPS EARLIER AFTERNOON AND EVENING WARM-SECTOR STORMS. SIMILAR TEMPERATURES TO PREVIOUS DAYS...GENERALLY UPPER 80S TO AROUND 90...AND LOWER 70S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... AS OF 150 PM WEDNESDAY... THE LONG TERM WILL BE CHARACTERIZED BY A FRONTAL ZONE CROSSING THE AREA AND STALLING IN THE VICINITY OF THE COAST BEFORE RETROGRADING BACK ACROSS OUR AREA THIS WEEKEND. AN EXTENDED PERIOD OF WET AND UNSETTLED WEATHER CAN BE EXPECTED THROUGH EARLY NEXT WEEK. CONSIDERING ALL THE ANTECEDENT RAINFALL WE HAVE HAD ACROSS CENTRAL NORTH CAROLINA...AND PRECIPITABLE WATER VALUES OVER 2 INCHES THROUGHOUT THE PERIOD...THE POTENTIAL FOR FLASH FLOODING WILL BE HIGH AND THE BIGGEST CONCERN FOR THIS FORECAST PERIOD. QPF FOR THIS PERIOD WILL MOST LIKELY BE A WIDESPREAD 1.5 TO 2 INCHES WITH SOME LOCALES EXPERIENCING HIGHER AMOUNTS IN TRAINING OR HEAVIER THUNDERSTORMS. THE FRONT WILL CROSS CENTRAL NC ON FRIDAY...DRIVEN BY A MID-ATLANTIC SURFACE LOW. THERE IS SOME UNCERTAINTY IN TIMING. THE LATEST GFS SHOWS A SLOWER PROGRESSION OF THE FRONT BUT MAY HAVE SOME ISSUES WITH SOME OF THE MESO-SCALE FEATURES THAT MAY FORM IN THE MEANTIME. THE NAM IS MUCH MORE PROGRESSIVE WITH THE FRONT BRINGING IT THROUGH THE CWA BEFORE 12Z FRIDAY WHILE THE GFS SLOWS THE FRONT AND HAS IT LINGER ACROSS THE AREA THROUGH 18Z. EITHER WAY MUCH OF THE CWA IF NOT ALL WILL BE WET WITH INCREASING CHANCES IN THE SOUTHEAST LATER IN THE DAY AS THE FRONT SETTLES OVER THE COASTAL PLAIN. THE FRONT WILL STAY SOUTHEAST OF THE AREA FOR MOST OF THE DAY ON SATURDAY BEFORE THE BERMUDA HIGH BEGINS TO SLOWLY WORK BACK TO THE WEST AND BEGIN A SLOW RETROGRADE OF THE FRONT LATE SATURDAY INTO SUNDAY MORNING. THE X FACTOR HERE WILL BE REMNANT MOISTURE ASSOCIATED CHANTAL WITH WHAT WILL MOST LIKELY BE CLASSIFIED AS A TROPICAL DEPRESSION AT THAT TIME. THIS COULD BRING MOISTURE BACK TO THE NORTH AND WEST A LITTLE QUICKER THAN THE CURRENT GFS SHOWS. TEMPERATURES DURING THIS PERIOD WILL BE IN THE MID 80S FOR HIGHS WITH LOWS IN THE UPPER 60S NORTHWEST TO LOWER 70S SOUTHEAST. ON SUNDAY SOUTHEASTERLY FLOW WILL RETURN TO THE AREA (PERHAPS LATER SUNDAY IN THE TRIAD) AND BEGIN A SLIGHT WARMING TREND WITH CONTINUED STRONG MOISTURE ADVECTION THROUGH THE DAY ON SUNDAY BEFORE BECOMING MORE EASTERLY AND SLIGHTLY LESS WET BUT PW VALUES WILL STILL HOVER AROUND 2 INCHES THROUGH TUESDAY. GRADUALLY THE HIGH IN THE WESTERN ATLANTIC WILL BUILD BACK IN AND SLOWLY HELP TO DRY THINGS OUT POSSIBLY BY WEDNESDAY. THICKNESS VALUES SUPPORT MAXIMUM TEMPERATURES FOR THIS PERIOD WILL GRADUALLY RISE FROM THE MID 80S TO NEAR 90 (AT LEAST IN THE SOUTHEAST) BY WEDNESDAY. LOWS GENERALLY IN THE UPPER 60S TO LOW 70S. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... AS OF 725 AM TUESDAY... PERSISTENCE. CONTINUED VERY HUMID SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE WILL MAINTAIN A FAMILIAR PATTERN CONSISTING OF EARLY MORNING (V)LIFR CEILINGS THAT WILL GRADUALLY LIFT AND SCATTER THROUGH MVFR RANGE...TO VFR...THROUGH 16-18Z. VFR CONDITIONS SHOULD THEN PREVAIL OUTSIDE OF SCATTERED SHOWERS AND STORMS THIS AFTERNOON AND EVENING...MOST LIKELY AT KFAY/KRWI/KRDU BETWEEN 17-22Z...AND AT TRIAD TERMINALS (KGSO/KINT) BETWEEN 21Z-02Z. SOME CONVECTION IS LIKELY TO LINGER OVERNIGHT...IN RESPONSE TO AN APPROACHING STRONG UPPER LEVEL TROUGH AND ASSOCIATED LIFT. LIFR CEILINGS SHOULD THEN REDEVELOP IN THE VERY HUMID REGIME LATE TONIGHT-EARLY THU. OUTLOOK... MORE OF THE SAME EXPECTED THROUGH THE WEEKEND...WITH SHOWER AND STORM COVERAGE MAXIMIZED LATE THU AND THU NIGHT...AND THROUGH FRI AT EASTERN TAF SITES...OWING TO THE APPROACH AND PASSAGE OF AN UPPER LEVEL TROUGH AND SURFACE COLD FRONT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...BLAES SHORT TERM...MWS LONG TERM...ELLIS AVIATION...MWS
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1115 AM CDT WED JUL 10 2013 .UPDATE... THIS MORNING/S MODELS CONTINUE TO STRUGGLE WITH A SOUTHWARD MOVING IMPULSE GENERATED BY LAST NIGHTS CONVECTION ACROSS PARTS OF KANSAS AND MISSOURI. MID LEVEL CLOUDS HAVE INCREASED JUST SOUTH OF THE RED RIVER THIS MORNING WHICH SHOWS THERE IS SOME MID LEVEL LIFT THAT MIGHT BECOME SLIGHTLY ENHANCED AS THE IMPULSE NEARS LATE THIS AFTERNOON/EVENING. DUE TO THIS REASONING...HAVE MAINTAINED 20-30 POPS FOR AREAS NORTH OF A DECATUR TO CANTON LINE THIS AFTERNOON THROUGH EVENING. ALSO DECIDED TO MAKE SOME ADDITIONAL LOCAL BIAS ADJUSTMENTS TO MAX TEMPS THIS AFTERNOON AND ON THURSDAY. WE ARE STILL EVALUATING THE RAIN POTENTIAL ASSOCIATED WITH THE NEXT TWO UPPER LEVEL SYSTEMS. THE FIRST DOES NOT LOOK THAT IMPRESSIVE DUE TO A LACK OF A GOOD TROPICAL FEED...BUT THE SECOND ONE NEXT WEEK MOVES FARTHER NORTH ACROSS THE STATE AND SEEMS TO HAVE A BETTER TROPICAL CONNECTION. 75 && .AVIATION... FOR THE 12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID FORECAST PERIOD. A SMALL CHANCE OF AFTERNOON STORMS NEAR THE DFW METROPLEX IS THE PRIMARY AVIATION WEATHER CONCERN. HIGH PRESSURE REMAINS IN PLACE OVER THE REGION WHICH WILL HELP MAINTAIN VFR CONDITIONS THROUGH THE FORECAST PERIOD. THUNDERSTORM ACTIVITY THAT OCCURRED OVER THE CENTRAL PLAINS EARLY THIS MORNING IS EXPECTED TO DISSIPATE WITH THEIR REMNANTS MOVING SOUTH TOWARDS NORTH TX THIS AFTERNOON. WITH 100 DEGREE HEAT EXPECTED...THE LATEST RAP FORECAST SOUNDINGS INDICATE AN UNCAPPED ENVIRONMENT FOR THUNDERSTORMS ALL AROUND THE DFW METROPLEX THIS AFTERNOON. ANY WEAK LIFT MAY BE SUFFICIENT TO CAUSE ISOLATED STORMS TO DEVELOP NEAR DFW AREA AIRPORTS DURING THE PEAK HEATING HRS OF THE DAY. CONFIDENCE IN THE REMNANTS OF THE CENTRAL PLAINS THUNDERSTORM ACTIVITY PROVIDING THIS LIFT REMAINS LOW...SO DO NOT HAVE A MENTION OF STORMS IN THE TAFS AT THIS TIME. SEVERAL HIGH RESOLUTION MODELS PRODUCE ISOLATED STORMS NEAR I-20 THIS AFTERNOON SO WILL HAVE TO WATCH SATELLITE IMAGERY CLOSELY FOR ANY SIGNS THAT A STORM WILL DEVELOP NEAR AREA AIRPORTS. DOWNBURST WINDS AND CLOUD TO GROUND LIGHTNING ARE THE EXPECTED IMPACTS FROM ANY THUNDERSTORMS. THUNDERSTORM CHANCES ARE EXPECTED TO DIMINISH AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. CAVANAUGH && .PREV DISCUSSION... /ISSUED 254 AM CDT WED JUL 10 2013/ BASED ON SOME DEEPER MOISTURE AND FORECAST CONVECTION EVIDENT ON THE RAP/NAM/TTU WRF/4KM WRF/HRRR...WE HAVE ADDED LOW POPS TO THE NORTH AND NORTHEAST THIS AFTERNOON. THERE IS ALSO SOME WEAK UPPER SUPPORT IN THE FORM OF A SHORT WAVE MOVING SOUTH DOWN THE BACK SIDE OF THE UPPER RIDGE THIS AFTERNOON. THIS DISTURBANCE IS ASSOCIATED WITH THE CURRENT CONVECTION IN KANSAS/MISSOURI. FOR THURSDAY...AFTERNOON/EVENING CONVECTION IN THE NORTHEAST NEAR A WEAK BACKDOOR FRONT STILL LOOKS PLAUSIBLE. BY FRIDAY THE RIDGE STARTS BUILDING BACK OVER NORTH TX SO ANY PRECIP SHOULD BE CONFINED TO FAR EASTERN COUNTIES. ON SATURDAY SOME OF THE DRIEST AIR OF THE WEEK MOVES ACROSS THE AREA. BY SATURDAY AFTERNOON DEW POINTS SHOULD DROP INTO THE 50S ACROSS MUCH OF THE AREA AS THE SHALLOW GULF MOISTURE MIXES WITH THIS DRY AIR ALOFT. THIS DRY AIR MASS WILL ALSO ALLOW A LITTLE EXTRA COOLING OVERNIGHT AND SUNDAY MORNING LOWS WILL BE ALMOST REFRESHING. IN THE EXTENDED...A TROPICAL LOW WILL MOVE INTO SOUTH TEXAS ON SUNDAY...AND WE SHOULD SEE SOME ISOLATED CONVECTION...AT LEAST IN THE SOUTH. COVERAGE IS LIKELY TO BE LOW AS WITH THE PREVIOUS SYSTEM THAT TOOK A SIMILAR PATH. GFS/ECMWF BOTH SHOW THAT BY SUNDAY MORNING A 500MB LOW OVER NEW YORK/NEW ENGLAND STARTS DROPPING SOUTH SOUTHWEST...REACHING MISSISSIPPI BY WEDNESDAY. THE ECMWF STALLS THIS LOW OVER THE LOWER MISSISSIPPI VALLEY...BUT THE GFS PUSHES IT WESTWARD ACROSS NORTH TX THU/FRI. IF THE LOW DOES MOVE INTO THE AREA...IT IS PROBABLY THE BEST CHANCE FOR MORE WIDESPREAD PRECIPITATION. THIS FAR OUT...HAVE KEPT THE POPS LOW AND WE WILL WAIT FOR A BETTER CONSENSUS. 84 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 100 79 100 78 100 / 20 20 20 20 10 WACO, TX 100 78 101 76 101 / 5 5 5 5 10 PARIS, TX 98 76 97 75 95 / 20 20 30 30 20 DENTON, TX 99 78 99 76 99 / 20 20 20 20 10 MCKINNEY, TX 99 78 99 76 98 / 20 20 30 30 10 DALLAS, TX 102 81 101 80 100 / 20 20 20 20 10 TERRELL, TX 100 78 99 76 99 / 20 20 20 20 10 CORSICANA, TX 101 77 100 76 100 / 10 10 10 10 10 TEMPLE, TX 100 75 100 74 101 / 5 5 5 5 5 MINERAL WELLS, TX 101 75 100 73 101 / 10 10 10 10 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /75
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
352 PM EDT WED JUL 10 2013 .SYNOPSIS... A DEEPENING UPPER TROUGH ACROSS THE GREAT LAKES WILL PUSH A COLD FRONT INTO THE REGION THURSDAY. DISTURBANCES IN ADVANCE OF THIS TROUGH WILL RESULT IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TODAY THROUGH THURSDAY ACROSS THE REGION. BEHIND THE COLD FRONT...COOLER...DRIER CONDITIONS ARE EXPECTED FOR FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY/... AS OF 317 PM EDT WEDNESDAY... A SERIES OF WEAK DISTURBANCES ALOFT WILL CROSS THE MIDDLE ATLANTIC REGION THIS AFTERNOON INTO TONIGHT. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE EAST INTO THE OUR REGION THURSDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS AFTERNOON INTO TONIGHT. WITH PWATS FROM 1.70 TO 2.0 INCHES AND A SLOW STORM MOTION...ANY THUNDERSTORMS THAT DEVELOPS COULD BE EFFICIENT RAIN PRODUCER. FFG VALUES REMAIN VERY LOW FROM RECENT HEAVY RAINFALL. GIVEN THE VERY WET ANTECEDENT SOIL CONDITIONS ACROSS THE REGION FROM THE PAST TWO WEEKS OF EXCESSIVE RAINFALL. DECIDED TO POST A FLASH FLOOD WATCH FOR THE WEST UNTIL 2 AM WITH HIGHER RAINFALL RATES ONE TO TWO POSSIBLE. A STRONGER THUNDERSTORM IS POSSIBLE INTO THIS EVENING WITH POTENTIAL FOR GUSTY WINDS AND HAIL. USED A BLEND OF THE HRRR AND THE RNK-WRFARW FOR POPS TONIGHT INTO THURSDAY. AS THE COLD FRONT MOVES EAST ON THURSDAY TAPER OFF POPS FROM THE NORTHWEST TO SOUTHEAST. A STRONGER THUNDERSTORM IS POSSIBLE IN THE SOUTH AND SOUTHEAST ON THURSDAY WITH THE POTENTIAL OF HEAVY RAIN. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 345 PM EDT WEDNESDAY... THURSDAY EVENING...SURFACE FRONT WILL BE WORKING ITS WAY ACROSS THE PIEDMONT WITH MODELS TAKING THE FRONT TO THE SANDHILLS OF NC BEFORE STALLING FRIDAY. NOT SURE HOW MUCH CLEARING WILL TAKE PLACE BEHIND THE FRONT AS THE UPPER LEVEL FLOW BECOMES BLOCKY WITH THE UPPER TROUGH ALSO STALLING ALOFT. AT THE VERY LEAST THINK DRYING WILL TAKE PLACE IN THE LOWER AND MID LEVELS AS THE AS WINDS TURN NORTHERLY...THEN NORTHEASTERLY AS SURFACE HIGH PRESSURE TRYS TO WEDGE INTO THE AREA FROM THE NORTH. ATTM...WILL REMAIN OPTOMISTIC AND KEEP FORECAST DRY FOR FRIDAY THROUGH AT LEAST THE FIRST HALF OF THE WEEKEND. AT SOME POINT WINDS WILL VEER WITH SOUTHEASTERLY FLOW BRINGING MOISTURE BACK INTO THE FORECAST. WENT WITH THE COOLER MAV MOS WITH THE THINKING THAT MORE CLOUD COVER AND A NORTHEASTERLY SURFACE WIND COMPONENT WILL KEEP THE NUMBERS DOWN. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 345 PM EDT WEDNESDAY... CAN`T SEEM TO SHAKE THE WET PATTERN. MODEL GUIDANCE GENERALLY AGREES THE UPPER TROUGH ALONG THE EAST COAST WILL BECOME STUCK...POSSIBLY CUTTING OFF AND RETROGRADING NEXT WEEK. THIS WILL QUICKLY TURN THE LOW LEVEL FLOW...WITH WINDS CHANNELLING DEEPER MOISTURE BACK INTO THE FORECAST AREA FAVORING HIGHER POPS. AS FOR TEMPS...DO NOT SEE ANY EXTREMES. 85H TEMPS HOVER AROUND +16 DEG C FOR MOST OF THE WEEK. WITH A MIX OF SUN AND CLOUDS THIS SHOULD YEILD HIGH TEMPS MAINLY IN THE 80S AND LOWS IN THE 60S. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... AS OF 145 PM EDT WEDNESDAY... SCATTERED MVFR SHOWERS AND THUNDERSTORMS WILL MOVE EAST ACROSS THE REGION TONIGHT INTO THURSDAY...AS UPPER TROUGH DEEPENS ACROSS THE GREAT LAKES REGION. EXPECT MORE WIDESPREAD MVFR/ISOLATED IFR CIGS TO DEVELOP MANY SITES AFT 00Z IN SHRA AND ISOLD TSRA...WHICH SHOULD PERSIST THROUGHOUT THE NIGHT. WINDS REMAINING SW5-7KTS THROUGH THE TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD...EXCEPT LOW TO MEDIUM CONFIDENCE IN THUNDERSTORMS. HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... LATEST MODELS CONTINUE TREND OF PUSHING CONVECTION MOSTLY INTO THE PIEDMONT THURSDAY...BUT EXPECT LINGERING SHRA/ISOLD TSRA FURTHER WEST. PERIODS OF MVFR-IFR CIGS APPEAR LIKELY EARLY THU...IMPROVING TO MVFR-VFR BY AFTERNOON. MUCH IMPROVED AVIATION CONDITIONS APPEAR IN THE OFFING FOR FRI-SAT AS SFC HIGH PRESSURE BUILDS DOWN FROM THE NORTH AND HIGH PRESSURE ALOFT BUILDS TO THE NORTH OF THE AREA. MODELS CONTINUE TO KEEP THE DEEPER MOISTURE AND ASSOCIATED TSRA ACTIVITY WELL SOUTH OF THE AREA DURING THIS TIME FRAME. THUS...MOSTLY VFR CONDITIONS ARE EXPECTED OUTSIDE OF TYPICAL EARLY MORNING IFR BR/FG. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR VAZ007-009>020- 022>024-032. NC...FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR NCZ001>003-018- 019. WV...FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR WVZ042>045. && $$ SYNOPSIS...RAB NEAR TERM...KK/RAB SHORT TERM...PM LONG TERM...PM AVIATION...KK/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
318 PM EDT WED JUL 10 2013 .SYNOPSIS... A DEEPENING UPPER TROUGH ACROSS THE GREAT LAKES WILL PUSH A COLD FRONT INTO THE REGION THURSDAY. DISTURBANCES IN ADVANCE OF THIS TROUGH WILL RESULT IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TODAY THROUGH THURSDAY ACROSS THE REGION. BEHIND THE COLD FRONT...COOLER...DRIER CONDITIONS ARE EXPECTED FOR FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY/... AS OF 317 PM EDT WEDNESDAY... A SERIES OF WEAK DISTURBANCES ALOFT WILL CROSS THE MIDDLE ATLANTIC REGION THIS AFTERNOON INTO TONIGHT. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE EAST INTO THE OUR REGION THURSDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS AFTERNOON INTO TONIGHT. WITH PWATS FROM 1.70 TO 2.0 INCHES AND A SLOW STORM MOTION...ANY THUNDERSTORMS THAT DEVELOPS COULD BE EFFICIENT RAIN PRODUCER. FFG VALUES REMAIN VERY LOW FROM RECENT HEAVY RAINFALL. GIVEN THE VERY WET ANTECEDENT SOIL CONDITIONS ACROSS THE REGION FROM THE PAST TWO WEEKS OF EXCESSIVE RAINFALL. DECIDED TO POST A FLASH FLOOD WATCH FOR THE WEST UNTIL 2 AM WITH HIGHER RAINFALL RATES ONE TO TWO POSSIBLE. A STRONGER THUNDERSTORM IS POSSIBLE INTO THIS EVENING WITH POTENTIAL FOR GUSTY WINDS AND HAIL. USED A BLEND OF THE HRRR AND THE RNK-WRFARW FOR POPS TONIGHT INTO THURSDAY. AS THE COLD FRONT MOVES EAST ON THURSDAY TAPER OFF POPS FROM THE NORTHWEST TO SOUTHEAST. A STRONGER THUNDERSTORM IS POSSIBLE IN THE SOUTH AND SOUTHEAST ON THURSDAY WITH THE POTENTIAL OF HEAVY RAIN. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 430 AM EDT WEDNESDAY... COLD FRONT ENTERING MUCH OF THE REGION MIDDAY THURSDAY...WITH SHOWERS/STORMS/CLOUDS WELL OUT AHEAD OF IT...COULD LIMIT ANY STRONGER THUNDERSTORMS TO SOUTHSIDE VIRGINIA AND THE NC PIEDMONT. STILL COULD ENCOUNTER SOME WATER PROBLEMS FOR THE FIRST HALF OF THE DAY THURSDAY THROUGH NW NC/EXTREME SW VA/SE WEST VA AFTER HEAVY RAIN ON WEDNESDAY. DRY AIR PUNCHES IN QUICKLY BEHIND THE BOUNDARY WITH RH TO ABOUT 40 PERCENT AT H7 BY THE AFTERNOON ACROSS THE NEW RIVER VALLEY. FRONT HANGS UP ACROSS THE EXTREME SOUTHEAST CWA AS IT ENCOUNTERS THE WESTERN ATLANTIC RIDGE. THUS...LEFT HIGHER POPS WELL INTO THE NIGHT ACROSS THOSE PARTS. ALL GUIDANCE SHOVES THE PRECIP OUT OF OUR SOUTHEAST BY FRIDAY AFTERNOON...WHICH IS A QUICKER SOLUTION THAN SOME OF THE PREVIOUS RUNS. WINDS VEER TO THE SE AND S ON SATURDAY RETURNING MORE MOISTURE IN THE MID LEVELS AND FOR NOW SLT CHC POPS ACROSS THE SOUTHEASTERN CWA. CONSIDERING THE STRENGTH OF THE TROUGH AND H85 TEMPS AS COLD AS +11C...DID GO A FEW DEGREES COOLER THAN GUIDANCE ON HIGHS AND LOWS THROUGH THE PERIOD. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 1225 PM EDT TUESDAY... PATTERN OVER OUR AREA WILL REMAIN SOMEWHAT UNSETTLED. WE ARE LOOKING AGAIN AT A FRONT SITUATED OVER THE COAST OF NC SOUTHWEST INTO GEORGIA FRIDAY NIGHT INTO SATURDAY TO STAY IN THIS GENERAL AREA THROUGH THE WEEKEND. MEANWHILE...WE HAVE SFC HIGH BUILDING SWD FROM THE NE AND MID ATLANTIC. QUESTION REMAINS WHERE THE BULK OF THE DEEPER MOISTURE WILL LIE. MODEL TRENDS HAVE FAVORED THAT MOST OF THE AREA WILL BE SOMEWHAT DRIER WHILE THE SRN CWA STAYS CLOSER TO THE SFC FRONT AND MORE THREAT OF SHOWERS AND STORMS. ALOFT...THE TROUGH AXIS LIES ACROSS THE MID ATLANTIC COAST AND SW OVER THE NW GULF OF MEXICO. DURING THIS TIME WILL HAVE TO WATCH HOW TS CHANTAL TRACKS. WPC/NHC SHOWING BY SUNDAY INTO MONDAY THAT CHANTAL WILL MOVE TOWARD EASTERN COAST OF FLORIDA. DURING THIS TIME THE SFC AND LOW LVL FLOW WILL BE OFF THE ATLANTIC COAST INTO OUR AREA AND WILL ENHANCE THE THREAT FOR SHOWERS AND STORMS WITH MONDAY STARTING TO LOOK LIKE THE WETTER DAY. STILL WE WILL HAVE TO WATCH HOW THINGS TREND AS MODELS STILL VARY SOMEWHAT STRENGTH AND POSITION OF UPPER LOW. GOING INTO TUESDAY...THE 00Z ECMWF WEAKENS THE UPPER LOW AS IT MOVES ACROSS OUR CWA WHILE THE LATEST GFS SHOWS UPPER LOW HANGING ON AND STRONG AS IT MOVES INTO NC. GIVEN THIS WILL KEEP AT LEAST A HIGH CHANCE...50 PERCENT FOR SHOWERS. DURING THIS TIME...THE TEMPERATURES ARE GOING BE SEASONAL...WITH HIGHS JUST BELOW NORMAL OVERALL AND LOWS STAYING MILDER. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... AS OF 145 PM EDT WEDNESDAY... SCATTERED MVFR SHOWERS AND THUNDERSTORMS WILL MOVE EAST ACROSS THE REGION TONIGHT INTO THURSDAY...AS UPPER TROUGH DEEPENS ACROSS THE GREAT LAKES REGION. EXPECT MORE WIDESPREAD MVFR/ISOLATED IFR CIGS TO DEVELOP MANY SITES AFT 00Z IN SHRA AND ISOLD TSRA...WHICH SHOULD PERSIST THROUGHOUT THE NIGHT. WINDS REMAINING SW5-7KTS THROUGH THE TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD...EXCEPT LOW TO MEDIUM CONFIDENCE IN THUNDERSTORMS. HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... LATEST MODELS CONTINUE TREND OF PUSHING CONVECTION MOSTLY INTO THE PIEDMONT THURSDAY...BUT EXPECT LINGERING SHRA/ISOLD TSRA FURTHER WEST. PERIODS OF MVFR-IFR CIGS APPEAR LIKELY EARLY THU...IMPROVING TO MVFR-VFR BY AFTERNOON. MUCH IMPROVED AVIATION CONDITIONS APPEAR IN THE OFFING FOR FRI-SAT AS SFC HIGH PRESSURE BUILDS DOWN FROM THE NORTH AND HIGH PRESSURE ALOFT BUILDS TO THE NORTH OF THE AREA. MODELS CONTINUE TO KEEP THE DEEPER MOISTURE AND ASSOCIATED TSRA ACTIVITY WELL SOUTH OF THE AREA DURING THIS TIME FRAME. THUS...MOSTLY VFR CONDITIONS ARE EXPECTED OUTSIDE OF TYPICAL EARLY MORNING IFR BR/FG. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR VAZ007-009>020- 022>024-032. NC...FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR NCZ001>003-018- 019. WV...FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR WVZ042>045. && $$ SYNOPSIS...RAB NEAR TERM...KK/RAB SHORT TERM...KM LONG TERM...WP AVIATION...KK/RAB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
313 PM CDT WED JUL 10 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 313 PM CDT WED JUL 10 2013 LATEST WATER VAPOR IMAGERY SHOWED NORTHWEST FLOW ALOFT OVER THE REGION. AN EMBEDDED SHORTWAVE WAS NOTED OVER SOUTHERN MANITOBA...HEADING SOUTHEAST. THIS WILL BE THE FEATURE TO KEEP A CLOSE EYE ON LATE THIS AFTERNOON THROUGH THIS EVENING AS IT MOVES ACROSS NORTHERN/CENTRAL WISCONSIN. ELSEWHERE ACROSS THE CONUS A TROUGH STRETCHED FROM THE EASTERN ONTARIO SOUTH THROUGH THE OHIO RIVER VALLEY. A RIDGE WAS NOTED OVER THE ROCKIES WITH ANOTHER TROUGH LOCATED JUST OFF OF THE WEST COAST. SURFACE OBSERVATIONS SHOWED HIGH PRESSURE OVER THE EASTERN DAKOTAS...EDGING EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE HIGH WAS PROVIDING MOSTLY TO PARTLY SUNNY SKIES THIS AFTERNOON ACROSS THE FORECAST AREA. NORTHWEST WINDS ARE USHERING IN A MUCH MORE COMFORTABLE AIRMASS WITH TEMPERATURE IN THE UPPER 70S TO LOWER 80S AND DEWPOINTS IN THE UPPER 40S TO MIDDLE 50S. THE SHORTWAVE TROUGH WILL MOVE ACROSS NORTHWEST WISCONSIN LATE THIS AFTERNOON AND PUSH SOUTH INTO CENTRAL WISCONSIN DURING THE EVENING HOURS. THE RAP AND NAM CONTINUE TO PRODUCE LIGHT PRECIPITATION WITH THIS FEATURES. ALSO...THE UPPER LEVEL SUPPORT IS FAIRLY HEALTHY WITH 500-300 MB POTENTIAL VORTICITY ADVECTION OF 12 TO 15 PVU/S. FORECAST SOUNDINGS OVER NORTH CENTRAL AND CENTRAL WISCONSIN ARE RATHER DRY THIS AFTERNOON AND THIS EVENING AS HIGH PRESSURE BUILDS IN AT THE SURFACE. GIVEN THE STRENGTH OF THE WAVE WOULD EXPECTED TO AT LEAST GET A FEW SPRINKLES OR LIGHT SHOWERS ALONG AND NORTHEAST OF THE INTERSTATE 94 CORRIDOR THIS EVENING...MAINLY IN THE 8PM TO 2AM TIMEFRAME. SURFACE HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN ACROSS THE FORECAST AREA ON THURSDAY PROVIDING MOSTLY SUNNY SKIES AND HIGHS IN THE 79 TO 83 DEGREE RANGE. DEEP MIXING DURING THE AFTERNOON HOURS WILL ALLOW DEWPOINTS TO FALL INTO UPPER 40S TO LOWER 50S. HAVE LOWERED DEWPOINTS A FEW DEGREES FROM PREVIOUS FORECAST. ALSO...WILL HAVE TO KEEP AN EYE ON AREAS OF FOG IN THE MORNING IN VALLEY LOCATIONS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 313 PM CDT WED JUL 10 2013 THE SURFACE HIGH WILL BE CENTERED OVER THE WESTERN GREAT LAKES THURSDAY NIGHT AS AN UPPER RIDGE BUILDS IN FROM THE NORTHERN PLAINS WITH DRY AND QUIET WEATHER IS EXPECTED THURSDAY NIGHT INTO FRIDAY. WARMER TEMPERATURES WILL START TO FILTER BACK INTO THE REGION AS THE HIGH SLIDES OFF TO THE EAST AND LOW PRESSURE DEVELOPS OVER THE PLAINS. THE BREEZY SOUTHERLY FLOW OVER THE REGION ON FRIDAY WILL ALLOW DEEP MIXING AND TEMPERATURES TO CLIMB INTO THE MID TO UPPER 80S UNDER MOSTLY SUNNY SKIES. THE RIDGE WILL FLATTEN SATURDAY INTO SUNDAY AS NUMEROUS EMBEDDED SHORTWAVES IN WEST/SOUTHWEST FLOW ALOFT TRACK ACROSS THE DAKOTAS THROUGH THE NORTHERN HALF OF MINNESOTA INTO NORTHERN WISCONSIN. THE BULK OF THE INSTABILITY REMAINS NORTH AND WEST OF THE FORECAST AREA. THERE IS AN INTERESTING FEATURE ADVERTISED IN THE GEM AND ECMWF...A RETROGRADING LOW MOVES WEST OUT OF THE CENTRAL APPALACHIANS SUNDAY INTO MONDAY AND APPROACHES THE MIDDLE MISSISSIPPI RIVER VALLEY. WILL HAVE TO KEEP A CLOSE WATCH ON THIS FEATURE LATE IN THE WEEKEND GOING INTO EARLY NEXT WEEK IF IT DOES MATERIALIZE. OTHERWISE...THE UPPER RIDGE ATTEMPTS TO ANCHOR OVER THE THE CENTRAL CONUS...STRETCHING INTO THE UPPER MISSISSIPPI RIVER VALLEY. ZONAL FLOW ALOFT...WITH EMBEDDED SHORTWAVES...OVER THE DAKOTAS THROUGH THE WESTERN GREAT LAKES WILL BRING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS. THE BULK OF THE ACTIVITY SHOULD OCCUR NORTH OF INTERSTATE 90 LATE THIS WEEKEND GOING INTO THE MIDDLE OF NEXT WEEK. WITH THE WARM SOUTHERLY FLOW OVER THE AREA AND MUCH OF THE CONVECTIVE ACTIVITY PASSING JUST TO THE NORTH OF THE AREA...DECIDED TO WARM HIGH TEMPERATURES 1 TO 2 DEGREES OVER A CONSENSUS MODEL BLEND...PRODUCING HIGHS IN THE UPPER 80S TO AROUND 90 && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1130 AM CDT WED JUL 10 2013 HIGH PRESSURE WILL DRIFT SOUTHEAST ACROSS THE REGION TODAY/TONIGHT. ENOUGH OF A PRESSURE GRADIENT AND DAYTIME MIXING TO PRODUCE GUSTY CONDITIONS FOR THE AFTERNOON HOURS...BUT WINDS SHOULD LIGHTEN UP QUICKLY TOWARD SUNDOWN. LIGHT WIND REGIME WILL THEN PERSIST THROUGH MUCH OF THU. COULD SEE A FEW MID/HIGH CLOUDS THIS EVENING...AND SOME CU FOR THU AFTERNOON. OVERALL...VFR CONDITIONS ARE EXPECTED INTO FRIDAY. ONE ITEM OF INTEREST IS AN UPPER LEVEL SHORTWAVE TROUGH THAT IS EXPECTED TO DROP SOUTHEAST OUT OF CANADA AND ACROSS THE REGION TONIGHT. IT COULD BRING SOME MID LEVEL CLOUDINESS FOR A SHORT PERIOD...AND PERHAPS SOME SHRA--. DON/T EXPECT A REDUCTION TO VSBY...ACCUMULATIONS...OR CHANGE FROM VFR CONDITIONS. NOT CONFIDENT ENOUGH TO INCLUDE A MENTION IN THE TAFS QUITE YET EITHER. SOMETHING TO MONITOR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION.....RIECK