Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/25/13


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
823 PM MDT FRI MAY 24 2013 .UPDATE... && .SHORT TERM...TSTMS HAVE ENDED OVER THE FAR NERN PLAINS. A BNDRY HAS WORKED ITS WAY BACK INTO THE FRONT RANGE BUT NO TSTMS HAVE DEVELOPED ALONG IT AS IT APPEARS AIRMASS IS CAPPED. STILL COULD SEE AN ISOLD STORM OR TWO OVER THE FAR NERN CORNER THRU MIDNIGHT SO WILL LEAVE IN LOW POPS OUT THERE. .AVIATION...DEEPER LOW LVL MOISTURE HAS SURGED BACK INTO THE AIRPORT. LATEST RAP SHOWS SOME POTENTIAL FOR STRATUS TO DVLP OVER SRN WELD COUNTY BY 10Z HOWEVER LOW LVL WINDS ARE FCST TO BECOME MORE SWLY BY THEN SO FOR NOW WILL KEEP STRATUS TO THE N AND NE OF DIA FOR LATER TONIGHT. AS FOR WINDS WILL KEEP THEN NELY THRU 05Z AND THEN GRADUALLY SHIFT THEM BACK TO SSW AFTER 06Z. && .HYDROLOGY...NO ISSUES && .PREV DISCUSSION... /ISSUED 249 PM MDT FRI MAY 24 2013/ SHORT TERM...CURRENT DEW POINT READINGS HAVE FALLEN INTO THE 20S- 30S F OVER THE SOUTHERN HALF OF THE PLAINS...AND INTO THE TEENS F IN THE MOUNTAINS AND FOOTHILLS. OVER THE REST OF THE PLAINS THEY ARE IN THE 40S-50S F...HIGHEST OVER THE NORTHEAST CORNER. SATELLITE PICTURES ARE SHOWING VERY LITTLE CONVECTIVE CLOUDINESS AT THIS TIME. THERE IS QUITE A BIT OF CIN OVER THE PLAINS RIGHT NOW. THERE IS A DENVER CYCLONE CENTERED NEAR DENVER INTERNATIONAL AIRPORT ALONG WITH A BOUNDARY STRETCHING FROM AROUND MORRISON IN JEFFERSON COUNTY TO CENTRAL ADAMS COUNTY. MODELS KEEP SOUTHWESTERLY FLOW ALOFT FOR THE CWA TONIGHT AND SATURDAY. THE SYNOPTIC SCALE ENERGY IS PROGGED TO BE BENIGN TONIGHT AND SATURDAY. BOUNDARY LAYER FLOW IS PROGGED TO BE NORMAL DRAINAGE TONIGHT AND MAINLY SOUTHWESTERLY DOWNSLOPING ON SATURDAY. SOME OF THE MODELS HANG ON TO EASTERLY FLOW OVER THE NORTHEAST CORNER ON SATURDAY. MOISTURE IS NOT GOOD...WITH THE EXCEPTION OF THE LOWER LEVELS OVER THE EASTERN PLAINS. DEW POINTS ARE PROGGED TO STAY ABOVE 50S F OVER THE NORTHEAST CORNER THIS EVENING...AND AGAIN SATURDAY AFTERNOON. PROGGED CAPES ARE FAIRLY DECENT OVER THE EASTERN PLAINS...OVER 2000 J/KG THIS EVENING. FOR POPS THIS EVENING...WILL STAY THE COURSE AND KEEP 10-30%S OVER THE NORTHEAST CORNER THROUGH MID TO LATE EVENING. THE SHEAR IS GOOD AND THE MOISTURE PLENTIFUL. NO POPS ELSEWHERE. FOR SATURDAY...THE DECENT CAPE IS PROGGED OVER THE NORTHEAST CORNER AGAIN. THE SHEAR IS NOT AS GOOD TO NO SEVERE MENTIONED THERE BUT WILL GO WITH 10-20%S FOR LATER AFTERNOON. SATURDAY`S HIGHS LOOK TO BE 0-1.5 C WARMER THAN TODAY`S CURRENT HIGHS. LONG TERM...SOUTHWEST FLOW ALOFT WILL CONTINUE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK AS UPPER LEVEL TROUGHING STAYS OVER THE PACIFIC NORTHWEST AND RIDGING REMAINS OVER THE CENTRAL US. THROUGH TUESDAY...NOT MUCH MOISTURE WILL BE ENTRAINED IN THIS SOUTHWEST FLOW...SO EXPECTING DRIER AND WARMER CONDITIONS THAN NORMAL. HIGHS IN THE 80S OVER THE PLAINS...IN THE 60S AND 70S IN THE MOUNTAINS...AND HUMIDITIES IN THE LOWER TEENS ARE EXPECTED THROUGH TUESDAY. THESE CONDITIONS DAY AFTER DAY WILL LIKELY BEGIN TAKING A TOLL ON THE FUELS AROUND THE STATE...HOWEVER CURRENTLY THE FUELS ARE LISTED AS STILL BEING GREEN ENOUGH AFTER OUR LATE SEASON MOISTURE. WILL KEEP EVALUATING THE FUELS EACH DAY TO DETERMINE ANY NEED FOR FIRE WEATHER HIGHLIGHTS. RIGHT NOW WINDS LOOK TO BE RIGHT AT OR BELOW CRITERIA. A SURFACE LOW WILL REMAIN NEARLY STATIONARY OVER THE CO/KS/NE STATE BORDERS KEEPING MOST OF THE AREA DRY AND LEAVING A CHANCE OF SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING OVER THE FAR NORTHEASTERN PLAINS. CAPE VALUES EACH AFTERNOON OVER THE NORTHEAST CORNER WILL VARY BETWEEN 500-1000 J/KG WITH STORM MOTION TO THE NORTHEAST. THERE WILL BE A VERY SMALL AMOUNT OF CAPE OVER THE MOUNTAINS SUNDAY AND MONDAY...BUT WITH NOT MUCH MOISTURE AVAILABLE. SO ANY SHOWERS OR THUNDERSTORMS THAT DO FORM WILL MAINLY HAVE LITTLE RAIN AND GUSTY WINDS. BEGINNING MONDAY NIGHT AND INTO MID-WEEK...THE PAC-NW TROUGH WILL GET AN EXTRA SHOT OF ENERGY AND PUSH A TROUGH SOUTHEAST TOWARD THE STATE. MODEL DIFFERENCES ARE GETTING LESS AS THE ECMWF USED TO DEEPEN THE TROUGH INTO A CUT-OFF LOW WHICH ITS DOING LESS NOW. THE TROUGH IS EXPECTED TO SWING FROM SOUTHWEST TO NORTHEAST ACROSS THE STATE FROM TUESDAY NIGHT THROUGH THURSDAY. THIS WILL INCREASE MOISTURE...SHOWER/TSTORM COVERAGE AND DECREASE TEMPERATURES OVER THIS PERIOD. FORECAST ALREADY HAD THIS TREND...ONLY MADE MINOR EDITS. AVIATION...PESKY WIND FIELDS TO DEAL WITH AS A DENVER CYCLONE IS IN AND NEAR KDEN. NORMAL DRAINAGE WIND PATTERNS SHOULD KICK IN LATER THIS EVENING. CONVECTION IS NOT EXPECTED TONIGHT OR SATURDAY WITH MOISTURE LACKING. HYDROLOGY...THE NORTHEAST CORNER OF THE FORECAST AREA COULD SEE SOME BRIEF HEAVY RAINS THIS EVENING. RAINFALL AMOUNTS COULD GET UP TO ONE HALF OF AN INCH...BUT FLOODING ISSUES SHOULD BE MINIMAL. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....KRIEDERMAN AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1043 AM EDT THU MAY 23 2013 .SYNOPSIS... A BERMUDA HIGH PRESSURE SYSTEM WELL OFF THE EAST COAST WILL SLOWLY RECEDE TODAY AND TONIGHT. A LOW PRESSURE SYSTEM MOVING THROUGH THE SAINT LAWRENCE VALLEY WILL SLOWLY DRAG A COLD FRONT INTO AND THROUGH THE REGION LATE TONIGHT INTO FRIDAY. A SECOND LOW PRESSURE SYSTEM WILL DEVELOP ON THE FRONT OFF THE NEW JERSEY COAST FRIDAY AND SLOWLY TRUNDLE NORTHEAST REACHING THE CANADIAN MARITIMES ON MONDAY. A HIGH PRESSURE SYSTEM WILL BUILD EAST IN ITS WAKE EARLY NEXT WEEK. A WARM FRONT IS FORECAST TO APPROACH AND MOVE THROUGH THE FORECAST AREA ON TUESDAY INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WITH THE MID-MORNING UPDATE, WE DECREASED POPS SOME FOR THE NEXT FEW HOURS ACROSS EASTERN AND SOUTHERN SECTIONS OF THE FORECAST AREA, BASED ON CURRENT RADAR IMAGERY AND THE LATEST HRRR GUIDANCE WHICH LOOKS TO BE CAPTURING TRENDS TODAY FAIRLY WELL. WE ALSO DECREASED T-STORM COVERAGE FROM SCATTERED TO ISOLATED UNTIL THIS AFTERNOON. HOURLY TEMPERATURES WERE ADJUSTED USING LAV/LAMP GUIDANCE, AS TEMPS WERE RISING A LITTLE FASTER THAN FORECAST IN SOME LOCATIONS. MAXIMUM TEMPERATURES LOOK ON TRACK FOR NOW, CONSIDERING THE CONSIDERABLE CLOUD COVER ACROSS THE REGION. HOWEVER, A FEW BREAKS ARE DEVELOPING ACROSS OUR DELMARVA REGION, AND THIS MAY ALLOW TEMPS TO RISE TO AROUND 80 DEGREES IN SOME LOCATIONS. WE WILL CONTINUE TO MONITOR AND UPDATE MAX TEMPS AS NEEDED. OTHERWISE, A RAINY PERIOD IS IN STORE TODAY AS SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE THROUGH THE DAY. SURFACE LOW PRESSURE WILL MOVE OUT OF THE GREAT LAKES AND INTO NEW ENGLAND TODAY, WHICH WILL PUSH A COLD FRONT THROUGH CENTRAL PENNSYLVANIA AND TOWARD OUR AREA LATER TODAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP AHEAD OF THE FRONTAL BOUNDARY. A PRE-FRONTAL, LEE-SIDE TROUGH IS EXPECTED TO DEVELOP DURING THE DAY WHILE A SHORT WAVE/VORT MAX MOVES ACROSS THE AREA AS WELL. THIS WILL LIKELY BE THE FOCUS FOR A LINE OF SHOWERS AND THUNDERSTORMS LATE IN THE DAY. THE SPC HAS PLACED A PORTION OF THE AREA UNDER A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON. ONE LIMITING FACTOR WILL BE THE EXPECTED CLOUD COVER ACROSS THE AREA WHICH MAY LIMIT THE AMOUNT OF INSTABILITY ACROSS THE AREA. BUT WE COULD STILL HAVE CAPE VALUES AROUND 500-1000 J/KG, AND WITH SHEAR VALUES AROUND 30-40 KNOTS, WE COULD HAVE A FEW STORMS BECOME ORGANIZED ENOUGH TO PRODUCE SOME STRONG WINDS. ANOTHER CONCERN TODAY WILL BE HEAVY RAINFALL. PW VALUES ARE FORECAST TO BE AROUND 1.50-1.75 INCHES. THEREFORE, SOME SHOWERS/THUNDERSTORMS COULD BE RATHER EFFICIENT RAIN PRODUCERS. POOR DRAINAGE AND URBAN/SMALL STREAM FLOODING IS POSSIBLE THIS AFTERNOON, ESPECIALLY IF ANY TRAINING OCCURS. MAV/MET MOS GUIDANCE WERE FAIRLY CLOSE, ALTHOUGH THE MAV WAS SLIGHTLY HIGHER. WE USED A BLEND, WITH MAJORITY OF THE MAV MOS. THIS WILL GIVE HIGHS GENERALLY IN THE MID-UPPER 70S, AND IF THE SUN COMES OUT AT ALL FOR AN EXTENDED PERIOD OF TIME, A FEW AREAS COULD REACH 80 DEGREES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING ACROSS THE AREA BY WEDNESDAY EVENING AS THE PRE-FRONTAL TROUGH MAKES ITS WAY ACROSS OUR AREA AND THE INITIAL SHORT WAVE MOVES ACROSS THE AREA. INSTABILITY WILL LIKELY DECREASE SOME AFTER SUNSET, BUT WITH MORE PVA EXPECTED TO TAKE PLACE OVERNIGHT IN THE CYCLONIC FLOW ALOFT, ALONG WITH THE PASSAGE OF THE FRONTAL BOUNDARY, SHOWERS AND THUNDERSTORMS COULD CONTINUE TO DEVELOP THROUGH THE NIGHT. THE FRONT WILL NOT CLEAR THE ENTIRE AREA OVERNIGHT, MAY BE NEAR THE COAST BY SUNRISE. WITH PW VALUES STILL AROUND 1.50-1.75 INCHES AHEAD OF THE FRONT, SOME HEAVY RAIN REMAINS POSSIBLE. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... NEITHER THE GFS NOR WRF-NMMB LOOKED STELLAR OFF THEIR INITIALIZATION. IN FACT A MODEL COMPROMISE SEEMED TO LOOK THE BEST. OVERALL THOUGH THE DP/DT WITH THE UPCOMING SYSTEM WAS SLOWER AND THIS FCST PACKAGE DID GO THAT WAY WITH A WETTER START TO THE HOLIDAY WEEKEND. THIS PACKAGE IS CLOSE TO THE GEFS MEAN WHICH IS SLIGHTLY MORE PROGRESSIVE THAN THE OP GFS AND CLOSEST TO A MODELING CONSENSUS. THE MODEL 500MB PATTERN FORECAST IS ANOMALOUS FOR LATE MAY, SO WE DID EDGE SLIGHTLY MORE PROGRESSIVE THAN THE SLOWER SOLUTIONS. THE SLOWING FRONT WILL BE MOVING THROUGH OUR CWA AS WE START THE LONG TERM. WITH THE TROF SHARPENING, IT BECOMES AN UNDERRUNNER WITH INSTABILITY STILL PRESENT ALOFT EVEN WITH THE BOUNDARY MOVING OFFSHORE. WE INCLUDED THE CHANCE OF THUNDER IN THE MORNING, BUT THEORETICALLY THUNDER COULD LINGER INTO THE AFTERNOON (FRI NIGHT OFF THE PREVIOUS ECMWF). NOT CONFIDENT ABOUT TEMP FCST AS DAYTIME MAX TEMP MAY BE DRIVEN BY HOW FAR TEMPS FALL BY 12Z FRIDAY. KIND OF RARE TO HAVE TEMPS GO NOWHERE ON A MAY DAY (AND ALSO HAVE THE CALENDAR DAY HIGH POSSIBLY OCCUR AT 101 AM) AND WE SHOWED A SLIGHT BUMP UP FOR NOW. AS THE TROF ALOFT CLOSES, MODEL DIAGS ARE SHOWING SOME RATHER ROBUST MID LEVEL QVEC CONVERGENCE AND FGEN FORCING FORECAST AND A DEVELOPING MID LEVEL TROWAL OVER OUR CWA WITH THE ENTRANCE REGION OF THE 250MB JET TO BOOT. ITS NO WONDER THAT QPF HAVE BECOME WETTER FRIDAY NIGHT AND SATURDAY. IT STILL DEPENDS UPON HOW QUICKLY AND FAR SOUTH THE 500MB LOW TRACKS. FOR NOW WE REMAIN MOST CONFIDENT FOR THE NORTHEASTERN PART OF OUR CWA. WHILE POPS WERE INCREASED FRIDAY NIGHT AND SATURDAY ACROSS THE BOARD, THE HIGHEST REMAIN IN THE NORTHEASTERN PART OF OUR CWA. WITH ONLY THE ECMWF SUPPORTING THUNDER FOR FRIDAY NIGHT (NONE OF THE MODELS DO ON SATURDAY), WE PRECLUDED THEM. CONDITIONS ARE EXPECTED TO IMPROVE AS SATURDAY MOVES ALONG, BUT WITH OUR CWA REMAINING UNDER THE CLOSED LOW, ITS GOING TO BE TOUGH TO GET MUCH SUNSHINE BEFORE WE SELF DESTRUCT. MIN AND MAX TEMPS WERE EDGED LOWER AND CLOSE TO A STAT GUIDANCE COMPROMISE. WE KEPT IN PCPN CHANCES FOR SATURDAY NIGHT NORTHEAST AND KEPT SUNDAY DRY. WE WILL STILL BE IN THE CYCLONIC FLOW OF THE CLOSED LOW, SO MORE SELF DESTRUCT SUNSHINE IS POSSIBLE, ESPECIALLY FARTHER NORTHEAST ONE IS WITHIN OUR CWA. WE SHOWED A TEMPERATURE IMPROVEMENT VS SATURDAY, CONFIDENCE THOUGH IS NOT HIGH UNTIL THE MODEL TREND SETTLES. WE DID NOT CHANGE MUCH IN THE REMAINDER OF THE LONG TERM. MONDAY LOOKS TO BE THE BEST DAY ON THE HOLIDAY WEEKEND WITH TEMPERATURES RETURNING TO NEAR NORMAL BY TUESDAY AND ABOVE NORMAL ON WEDNESDAY. WE KEPT LOW CHANCE POPS IN ASSOCIATED WITH THE NEXT APPROACHING WARM FRONT. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. A CLOUDY, RAINY PERIOD EXPECTED TODAY AS SHOWERS, AND POSSIBLE THUNDERSTORMS, ARE EXPECTED TO INCREASE THROUGH THE DAY AHEAD OF AN APPROACHING COLD FRONT. CEILINGS ACROSS MUCH OF THE REGION ARE IN THE MVFR RANGE, AND WE EXPECT THIS TREND TO HOLD THROUGH MUCH OF THE DAY. AS MENTIONED, SHOWERS ARE EXPECTED TO INCREASE IN COVERAGE THROUGH THE DAY AND COULD REDUCE VSBYS IF HEAVY ENOUGH. THERE IS ALSO THE POTENTIAL FOR THUNDERSTORMS, MAINLY THIS AFTERNOON INTO THIS EVENING, SO WE WILL KEEP THEM IN THE FORECAST FOR NOW. THE COLD FRONT IS NOT EXPECTED TO CROSS THE AREA UNTIL OVERNIGHT THURSDAY INTO FRIDAY MORNING. CONDITIONS COULD LOWER MORE AHEAD OF THE FRONTAL BOUNDARY THURSDAY NIGHT, AND SHOWERS WILL LIKELY CONTINUE AT LEAST UNTIL THE FRONT MOVES INTO THE REGION. OUTLOOK... FRIDAY THROUGH SATURDAY...MVFR TO POSSIBLY IFR CONDITIONS DUE TO CLOUDS AND SHOWERS. WORST CONDITIONS EXPECTED AT NORTHEASTERN TERMINALS AND AIRPORTS. CONDITIONS COULD IMPROVE AS SATURDAY CONTINUES. NORTH TO NORTHWEST WIND GUSTS COULD EXCEED 20 KTS. SATURDAY NIGHT THRU MONDAY...MOSTLY VFR. SOME GUSTY NORTHWEST WINDS POSSIBLE ON SUNDAY. && .MARINE... SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR TODAY AND TONIGHT AS WINDS ARE EXPECTED TO CONTINUE TO GUST NEAR 25 KNOTS IN THE SOUTH-SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING COLD FRONT. SEAS ARE EXPECTED TO CONTINUE TO INCREASE TO NEAR 5-6 FEET TODAY INTO TONIGHT AS WELL. OUTLOOK... THE SCA FLAG HAS BEEN EXTENDED INTO FRIDAY DAY FOR NOW. WINDS MAY NOT BE A FACTOR, BUT SWELLS SHOULD REMAIN. THE INCREASING NORTHWEST FLOW AROUND THE DEVELOPING LOW SHOULD RESULT IN MORE SMALL CRAFT ADVISORY CONDITIONS ON ALL OUR AREA WATERS LATER FRIDAY INTO SATURDAY EVENING. THERE IS A SMALL CHANCE THAT EVEN GALE FORCE WIND GUSTS MIGHT OCCUR FOR A TIME ON SATURDAY. SMALL CRAFT ADVISORY WIND GUSTS MIGHT LINGER ON THE OCEAN INTO SUNDAY MORNING. AFTER THAT SUB SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED FOR THE REST OF THE HOLIDAY WEEKEND. && .RIP CURRENTS... THERE IS A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS ALONG THE COAST OF NEW JERSEY TODAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR ANZ450>455. && $$ SYNOPSIS...GIGI/O`HARA NEAR TERM...KLINE/ROBERTSON SHORT TERM...ROBERTSON LONG TERM...GIGI AVIATION...GIGI/ROBERTSON/O`HARA/KLINE MARINE...GIGI/ROBERTSON/O`HARA RIP CURRENTS...ROBERTSON/KLINE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
355 PM EDT THU MAY 23 2013 .DISCUSSION... TONIGHT... H100-H70 ANTICYCLONE OVER THE N CNTRL GOMEX WILL GENERATE A DEEP NW FLOW ACRS CENTRAL FL OVERNIGHT. LATEST RAP ANALYSIS SHOWS LIMITED INSTABILITY ACRS CENTRAL FL...COMMON IN SUCH A FLOW REGIME. WEAK LOW LVL PGRAD ALLOWED THE EAST COAST SEABREEZE TO DVLP BY MID AFTN...WHICH WILL PUSH STEADILY INLAND THROUGH SUNSET. ISOLD SHRAS/TSRAS ALONG AND N OF THE I-4 CORRIDOR SHOULD DISSIPATE BY SUNSET WITH THE LOSS OF DAYTIME HEATING. WEAK FRONTAL BNDRY WILL PUSH INTO THE FL STRAITS...ALLOWING A LIGHT W/NW BREEZE TO PREVAIL OVER LAND OVERNIGHT. DEEP LYR DRY AIR ADVECTION WILL ALLOW SKIES TO BCM MCLR OVERNIGHT...UPSTREAM SFC DEWPOINTS OVER N FL SUGGEST MIN TEMPS IN THE M/U60S...GENERALLY WITHIN A DEG OR TWO OF CLIMO AVG. FRI-FRI NIGHT... CONTINENTAL RIDGE OVER THE CENTRAL/NRN PLAINS WILL BUILD INTO THE DEEP SOUTH...RESULTING IN A STEADY NW TO NE BREEZE THRU THE H100-H70 LYR THAT WILL BRING OVERALL DRY WX TO E CNTRL FL. LATE SEASON COOL FRONT WILL BRING LIMITED MOISTURE TO THE CENTRAL PENINSULA...WHILE LATEST RAP ANALYSIS INDICATES LIMITED POTENTIAL FOR MID LVL VORTICITY ADVECTION OR UPR LVL EVACUATION. PRECIP CHANCES WILL BE LIMITED TO AREAS S OF THE I-4 CORRIDOR...BUT WITH LIMITED MOISTURE AND INSTABILITY TO WORK WITH...ANTICIPATE AFTN COVERAGE AOB 20PCT...SHIFTING OFFSHORE AFT SUNSET. W/NW FLOW WILL PREVENT SEA BREEZE FORMATION N OF THE CAPE...MAYBE LATE DAY DEVELOPMENT ALONG THE TREASURE COAST. NEAR FULL SUN WILL ALLOW TEMPS TO WARM TO THE U80S ALONG THE COAST...L90S INLAND. WEAK ONSHORE FLOW WILL DVLP OVERNIGHT AS THE RIDGE AXIS DRIFTS EWD...KEEPING MIN TEMPS SLIGHTLY ABV AVG...M/U60S INTERIOR AND U60S/L70S ALONG THE COAST. SAT-TUE...(PREV DISC) IT WILL BE A WARM AND DRY MEMORIAL DAY WEEKEND ACROSS THE AREA AS NORTH-NORTHWEST FLOW ALOFT BEHIND THE TROUGH USHERS IN DRY AIR THAT WILL STAY IN PLACE INTO EARLY NEXT WEEK. AT THE SURFACE...STOUT ONSHORE FLOW WILL DEVELOP ON SATURDAY AS THE SURFACE HIGH OVER THE GREAT LAKES BUILDS TO THE SOUTHEAST AND OFF THE CAROLINA COAST WITH ITS AXIS ACROSS NORTH FLORIDA INTO NEXT WEEK. FLOW WILL BE STRONG ENOUGH AND DEEP ENOUGH THAT A FEW ATLANTIC SHOWERS REACHING THE COAST CAN`T BE RULED OUT...ESPECIALLY ACROSS THE TREASURE COAST WHERE MOISTURE WILL BE HIGHER. HOWEVER THE PROBABILITY THIS FAR OUT REMAINS TO LOW TO MENTION. ONSHORE FLOW WILL KEEP HIGH TEMPERATURES A FEW DEGREES COOLER IN THE LOW-MID 80S ALONG THE COAST AND MID-UPPER 80S INLAND. POST FRONTAL DRY AIR AND MOSTLY CLEAR SKIES SHOULD ALLOW TEMPERATURES TO DROP INTO THE LOW TO MID 60S ACROSS THE INTERIOR SAT-SUN NIGHTS BEFORE THE GRADUALLY MOISTENING IN ONSHORE FLOW BRINGS LOWS UP IN THE MID-UPPER 60S. COASTAL TEMPS REMAIN WARM AND MUGGY IN THE LOW-MID 70S. LOCATIONS WHERE WINDS DROP OVERNIGHT OR WEAK DRAINAGE FLOW DEVELOPS MAY DROP SEVERAL MORE DEGREES INTO THE MID 60S. && .AVIATION... VFR ALL SITES UNLESS OTHERWISE NOTED. BTWN 23/20Z-23/24Z...ISOLD MVFR SHRAS/IFR TSRAS E OF KDAB-KOBE. BTWN 24/08Z-24/12Z...LCL IFR CIGS/VSBYS IN BR. && .MARINE... TONIGHT...LIGHT TO GENTLE E/SE BREEZE NEARSHORE THRU SUNSET DUE TO THE INLAND MOVING EAST COAST SEA BREEZE...WRLY BREEZE OFFSHORE IN THE WAKE OF A WEAK FRONTAL BNDRY PUSHING INTO THE FL STRAITS. SFC/BNDRY LYR WINDS LIGHT AND VARIABLE BCMG W/SW OVERNIGHT AS HI PRES OVER THE CENTRAL GOMEX IS ABSORBED BY A LARGER CONTINENTAL RIDGE BUILDING OUT OF THE CENTRAL/NRN PLAINS. SEAS MAINLY 2-3FT... UP TO 4FT IN THE GULF STREAM N OF CAPE CANAVERAL. FRI-FRI NIGHT...LIGHT TO GENTLE NW WINDS BCMG N/NE THRU THE DAY AS THE CONTINENTAL RIDGE BUILDS INTO THE DEEP SOUTH. LCL PGRAD WILL TIGHTEN LATE FRI NIGHT AS THE RIDGE BUILDS INTO THE REGION...WINDS WILL RESPOND BY FRESHENING TO 10-15KTS NEARSHORE AND ARND 15KTS OFFSHORE. SEAS 2-3FT NEARSHORE AND 3-4FT OFFSHORE THRU LATE FRI NIGHT...BUILDING TO 3-5FT N OF SEBASTIAN INLET AND 2-4FT S OF THE INLET BY DAYBREAK SAT. MEMORIAL DAY WEEKEND...(PREV DISC) MODELS HAVE BACKED OFF SLIGHTLY ON THE MAGNITUDE OF THE NORTHEAST WINDS SURGE SAT MORNING...THOUGH STILL EXPECT SPEEDS AROUND 15-20KTS THROUGH LATE SAT NIGHT AS HIGH PRESSURE BUILDS IN BEHIND THE FRONTAL BOUNDARY. WINDS WILL DIMINISH SLIGHTLY INTO THE OVERNIGHT HOURS INTO SUNDAY AS THEY VEER TO THE EAST AROUND 15KTS. LIGHTEST WINDS WILL BE NORTH OF CAPE CANAVERAL INTO MONDAY AT 10-15KTS WHICH WILL BE CLOSEST TO THE RIDGE AXIS. WIND SURGE WILL BRING SEAS TO AROUND 6FT OFFSHORE SAT AFTERNOON/NIGHT WITH THE OFFSHORE FLOW KEEPING HEIGHTS 4-5FT THROUGH THE REMAINDER OF THE HOLIDAY WEEKEND. && .FIRE WEATHER... NWRLY TRANSPORT FLOW WILL GENERATE MODERATE DRY AIR ADVECTION THRU THE END OF THE WEEK...RESULTING IN LITTLE IF ANY MEASURABLE PRECIP. RH VALUES ALONG AND N OF THE I-4 CORRIDOR WILL FALL BLO 35PCT FOR A FEW HRS EACH AFTN...BUT SFC PGRAD SHOULD BE LOOSE ENOUGH TO ALLOW THE EAST COAST SEA BREEZE TO DEVELOP...KEEPING COASTAL AFTN RH VALUES NEAR 50PCT. && .PRELIMINARY POINT TEMPS/POPS... DAB 70 88 68 80 / 10 10 0 0 MCO 69 92 69 86 / 10 10 0 0 MLB 71 88 72 81 / 10 20 10 0 VRB 71 88 72 82 / 10 20 10 0 LEE 69 91 66 86 / 10 10 0 0 SFB 69 91 69 85 / 10 10 0 0 ORL 70 92 69 86 / 10 10 0 0 FPR 71 89 72 82 / 10 20 10 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX...PENDERGRAST
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
345 PM EDT THU MAY 23 2013 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER CHAOTIC UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS DOMINATED BY THREE LONGWAVE FEATURES. LOOKING FAR UPSTREAM WE FIND A LARGE AND VIGOROUS UPPER LEVEL LOW SPINNING OVER THE PACIFIC NORTHWEST. MAIN FLOW AROUND THE SOUTHERN PERIPHERY OF THIS CIRCULATION EMERGES THROUGH THE FOUR-CORNERS REGION AND THEN RIDGES UP OVER THE CENTRAL PLAINS. THIS FLOW THEN QUICKLY DIVES BACK TO THE SOUTHEAST AND MERGES WITH AN IMPRESSIVE LONGWAVE TROUGH PIVOTING THROUGH MUCH OF EASTERN CANADA AND THE EASTERN CONUS. OUR FORECAST AREA RESIDES NEAR THE SOUTHERN PERIPHERY/BASE OF THIS EASTERN TROUGH. WV IMAGERY CLEARLY DEFINES A WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WITHIN THE BASE OF THE LONGWAVE TROUGH WHICH IS PIVOTING THROUGH THE REGION THIS AFTERNOON...AND WILL BE OFF TO OUR EAST BY TONIGHT. MID/UPPER LEVEL DRY AIR IS EXPANDING ACROSS THE REGION WITH WEAK NVA AND LARGE SCALE SUBSIDENCE IN THE WAKE OF THIS DEPARTING SHORTWAVE. AT THE SURFACE...A WEAK PRESSURE GRADIENT IS RESULTING IN MAINLY SEA-BREEZE DOMINATED FLOW LATE TODAY. THE WEST COAST SEA-BREEZE IS QUICKLY BEGINNING TO TRANSLATE INLAND CLEARING THE DIURNAL CUMULUS FIELD AWAY FROM THE BEACHES. MAY STILL SEE A FEW INTERIOR ISOLATED CONVECTIVE CELLS INTO THE EARLY EVENING...HOWEVER COVERAGE LOOKS TO BE SIGNIFICANTLY LESS THAN WHAT WAS EXPERIENCED THE PAST COUPLE OF DAY. && .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... TONIGHT... LARGE SCALE SUBSIDENCE PATTERN SUGGESTS ANY LINGERING STORMS BY MID-EVENING WILL BE OVER TOWARD THE I-95 CORRIDOR WHICH SHOULD SET UP A MAINLY DRY...QUIET AND SEASONABLE OVERNIGHT PERIOD FOR OUR ZONES. TEMPERATURES WILL GENERALLY DROP TO THE MID 60S TO LOWER 70S BY SUNRISE ON FRIDAY...WITH THE NORMALLY COLDER INLAND SPOTS DOWN INTO THE LOWER 60S. FRIDAY/FRIDAY NIGHT... EASTERN CONUS UPPER LEVEL TROUGH IS FORECAST TO SHARPEN AS ITS AXIS REACHES THE ATLANTIC COAST DURING FRIDAY. SURGE OF ENERGY ROUNDING THE BASE OF THIS TROUGH DURING THIS TIME WILL PASS TO OUR NORTH...HOWEVER IT WILL ACT TO PROPEL A LATE SEASON TROUGH/FRONT DOWN AND ACROSS THE FL PENINSULA. SIGNIFICANTLY DRIER AIR WILL BE ARRIVING BEHIND THIS FRONT...ESPECIALLY ABOVE THE SURFACE WHICH SHOULD SUPPRESS MUCH IF NOT ALL OF THE DIURNAL CONVECTION FROM THE TAMPA BAY AREA NORTHWARD ALONG THE NATURE COAST. SOME LINGERING MOISTURE AND SEA-BREEZE COLLISION WITHIN A WEAK GRADIENT OVER THE SOUTHERN ZONES SHOULD BE ENOUGH FOR A FEW LATE DAY STORMS...MAINLY INLAND FROM THE I-75 CORRIDOR. STRONG CONTINENTAL HIGH PRESSURE BEGINS TO BUILD OVER THE PENINSULA DURING FRIDAY NIGHT WITH A TIGHTENING PRESSURE GRADIENT AND DEVELOPING NE FLOW. DRIER AIR WILL CONTINUE TO ADVECT INTO THE AREA...EVEN AT THE SURFACE AND LEAD TO A NOTICEABLY COOLER OVERNIGHT PERIOD. IN FACT...A FEW SPOTS UP TOWARD CITRUS/LEVY COUNTY MAY FIND THEMSELVES BACK INTO THE 50S FOR A FEW HOURS TOWARD DAWN ON SATURDAY. SATURDAY/SATURDAY NIGHT... ON THE BACKSIDE OF THE DEPARTING UPPER TROUGH...AN UNSEASONABLY DRY MID-LEVEL AIRMASS WILL DESCEND OVER THE REGION FOR SATURDAY AND SATURDAY NIGHT. CROSS-SECTION AND TIME-HEIGHT ANALYSIS FROM THE GFS AND NAM BOTH SHOW AVERAGE RELATIVE HUMIDITY THROUGH THE 850-400MB LAYER AT UNDER 10%...THAT IS DRY! IN ADDITION...THETA-E VALUES AROUND 700MB ARE FORECAST TO DROP BELOW 315K ALMOST REGION-WIDE BY SATURDAY AFTERNOON. THIS COMBINATION ALONG WITH THE SYNOPTIC FLOW DISRUPTING THE SEA-BREEZE FORMATION WILL LEAD TO LITTLE IF ANY CHANCES FOR DIURNAL CONVECTION. WILL KEEP THE FORECAST DRY FOR THE FIRST HALF OF THE WEEKEND UNDER PLENTY OF SUNSHINE AND SEASONABLE TEMPERATURES. THE DRY CONDITIONS WILL LEAD TO ANOTHER BELOW AVERAGE NIGHT IN TERMS OF TEMPERATURES...WITH WIDESPREAD LOWER 60S AWAY FROM THE COAST BY DAWN ON SUNDAY. ONCE AGAIN COLDER SPOTS ACROSS THE NATURE COAST ARE FORECAST TO DROP INTO THE MID/UPPER 50S. && .LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)... MODEL SOLUTIONS REMAIN IN GOOD AGREEMENT SHOWING HIGH PRESSURE RIDGE AXIS REMAINING NORTH OF THE FORECAST AREA...KEEPING AN EASTERLY BOUNDARY LAYER FLOW IN PLACE. MOISTURE WILL REMAIN LIMITED THROUGH MONDAY NIGHT...WITH RAIN FREE CONDITIONS EXPECTED. BOUNDARY LAYER MOISTURE WILL INCREASE SLIGHTLY DURING THE MID WEEK TIME FRAME...SO WILL CARRY SLIGHT CHANCE POPS FOR PORTIONS OF THE AREA TUESDAY THROUGH THURSDAY FOR AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS. && .AVIATION... PREVAILING VFR WITH FEW-SCT CLOUDS...ISOLD TSRA EAST OF THE TERMINALS THROUGH EARLY EVENING. LIMITED BR MAY BE POSSIBLE AT LAL AND PGD. WESTERLY WINDS BECOME LIGHT AND VARIABLE OVERNIGHT THEN NORTHWESTERLY DURING THE DAY. && .MARINE... WEAK HIGH PRESSURE ACROSS THE EASTERN GULF SLIDES OFF TONIGHT AS A DRY FRONT MOVES SOUTHWARD FRIDAY AND INTO SOUTH FLORIDA. HIGH PRESSURE BUILDS INTO THE GULF REGION SATURDAY THEN MOVES EAST...AS IT CONTINUES TO DOMINATE THE EAST GULF WATERS. THE BUILDING HIGH PRESSURE RESULTS IN A TIGHTENING PRESSURE GRADIENT WITH GUSTY EAST AND NORTHEAST WINDS POSSIBLY REACHING CAUTIONARY OR LOW END ADVISORY CRITERIA AT TIMES. && .FIRE WEATHER.. A LATE SEASON FRONT WILL DROP SOUTH ACROSS THE REGION FRIDAY AND FRIDAY NIGHT ALLOWING A MUCH DRIER AIRMASS TO FILTER IN FROM THE NORTH FOR THE UPCOMING WEEKEND. RELATIVE HUMIDITY VALUES ARE FORECAST TO DROP BELOW CRITICAL VALUES FOR A PERIOD FRIDAY AFTERNOON AWAY FROM THE COAST WITH THE LOWEST VALUES AND LONGEST DURATIONS FROM THE I-4 CORRIDOR AND NORTHWARD. ANOTHER DAY WITH A PERIOD OF CRITICALLY LOW RELATIVE HUMIDITY IS ANTICIPATED FOR SATURDAY. A NORTHEAST WIND WILL HELP BRING THESE LOW RELATIVE HUMIDITY VALUES BACK CLOSER TO THE COAST. && .PRELIMINARY POINT TEMPS/POPS... TPA 73 91 69 87 / 0 0 0 0 FMY 72 92 70 91 / 10 10 10 10 GIF 71 93 67 90 / 10 10 10 0 SRQ 71 90 70 90 / 0 0 0 0 BKV 65 91 62 87 / 0 10 10 0 SPG 75 90 73 87 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/FIRE WX...MROCZKA AVIATION/MARINE/DECISION SUPPORT...RUDE LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1057 AM EDT Thu May 23 2013 .NEAR TERM [Rest of Today]... The 12 UTC sounding from our office had a relatively moist profile with a PWAT of 1.53". However, drier air is situated just to the northwest, with the Birmingham (BMX) sounding indicating much drier air in the 950-800mb layer. This is portrayed in the latest objective RAP analysis which shows the leading edge of the drier air just arriving in our southeast Alabama zones. This is expected to push into the northwest half of our area by early afternoon, and as boundary layer mixing increases, surface dewpoints should decrease markedly. The advection of drier air from the northwest will also set up a low-level thetae gradient somewhere near an AAF-VLD line by afternoon. Various convection-allowing models show scattered showers and thunderstorms developing in the unstable environment ahead of this boundary in the afternoon - mainly in Taylor, Lafayette, and Dixie counties. Therefore, a 20% PoP was added in areas southeast of Tallahassee. It wouldn`t be out of the question for some of the storms to produce some hail or gusty winds, but widespread or organized severe weather is not expected. Otherwise, it looks like a mostly sunny and seasonably warm day with highs within a couple degrees of 90 in most spots. && .SHORT TERM [Tonight through Sunday]... TONIGHT...the large scale longwave pattern remains highly amplified with full latitude trough over Wrn, ridge over Cntrl and trough over Ern states followed by ridge over extreme Wrn Atlc. Low assocd with Ern trough continuing to weaken as it shears NEWD. At surface, low vcnty PA with weakening cold front Swd to N GA then SWWD across SE AL. During the rest of overnight hours, axis of Ern trough to move to Ern seaboard with rapidly weakening mainly dry front reaching extreme Nrn Gulf waters by sunrise FRI. FRIDAY THRU SUNDAY...By Fri eve, trough axis and assocd low just off Ern seaboard. In their wake, upper ridge will build NWD from Wrn Gulf of Mex while surface high pressure builds SWD from the OH/ TN Valleys to the Nrn Gulf. Assocd ridge will continue to build SEWD Fri night into SAT with high centered NNE of region. Locally this places local area between departing trough and advancing upstream ridge yielding a much cooler and drier airmass with NW steering flow. Flow aloft becoming WNW by Sun, and with NLY flow at lower levels veering to NE on Sat and ESE on Sun. The result is a reinforcing dry airmass heralding an ideal weekend with mostly clear skies, low dew points and cool nights. 10% pops tonight then no POPs thru period. Inland Lows tonight low to mid 60s dropping Fri and Sat nights in wake of front to mid 50s. Highs generally mid to upper 80s. Invading drier air should limit fog chances thru period. && .LONG TERM [Sunday Night through Wednesday]... Upper ridging will build over the area through Memorial Day and into the middle of next week. This will leave somewhat tranquil conditions in place with a seasonably cool start to the period and a gradual warm up into the early part of the week, with little or no rain outside of possible isolated showers along the sea breeze. && .AVIATION...[through 06 UTC Friday] Areas of fog will develop in the pre-dawn hours. Some of the fog may become dense especially in places that received rain. VFR conditions will return across the entire region after 14Z. Winds will be from the west to northwest in the 10 to 15 knot range with higher gusts. && .MARINE... Fairly low winds and seas will persist into Friday, when offshore winds will increase in the wake of a surface cold front late Friday night into Saturday. Seas will eventually build as well in the offshore legs with cautionary wind speeds expected Friday night. winds will veer and along with seas decrease thru the rest of the weekend. && .FIRE WEATHER... A much drier airmass will be filtering into the region over the next few days. Today the minimum relative humidity should stay above critical levels but is forecast to drop at or just below 28 percent over interior portions of the Florida Panhandle and western Big Bend Friday afternoon. This combined with elevated ERC values and sustained winds at or above 15 mph will possibly meet Red flag conditions. A fire weather watch has been posted and may be upgraded to a warning later today. A fire weather watch will also be issued for our SE Alabama counties Friday due to a combination of long durations of low RH, KBDI over 500 and sustained winds at or above 10 mph. Low relative humidities are also expected across our Georgia zones Friday but the 10-hour fuel moisture should remain above 6 percent. Red Flag conditions are also possible across portions of north Florida and our southeast Alabama counties again on Saturday. On top of all this, dispersions will be very high across north Florida this afternoon and again on Friday with forecast values approaching 120. && .HYDROLOGY... No issues are forecast along area rivers for the foreseeable future. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 92 66 89 56 87 / 10 10 10 10 0 Panama City 87 75 87 66 81 / 10 10 10 10 0 Dothan 91 66 87 55 86 / 0 10 10 10 0 Albany 90 64 85 55 85 / 10 10 10 10 0 Valdosta 92 63 87 56 85 / 10 10 10 10 0 Cross City 88 67 89 58 86 / 20 10 10 10 0 Apalachicola 84 72 87 66 82 / 10 10 10 10 0 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...FIRE WEATHER WATCH from Friday afternoon through Friday evening for Calhoun-Gadsden-Holmes-Inland Walton-Jackson- Liberty-Washington. GA...None. AL...FIRE WEATHER WATCH from Friday afternoon through Friday evening for Coffee-Dale-Geneva-Henry-Houston. GM...None. && $$ NEAR TERM...Lamers SHORT TERM...Block LONG TERM...Evans AVIATION...Barry MARINE...Block FIRE WEATHER...Barry HYDROLOGY...Evans/Block
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
950 AM EDT THU MAY 23 2013 .UPDATE (REST OF TODAY AND TONIGHT)... 13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER CHAOTIC UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS DOMINATED BY THREE LONGWAVE FEATURES. LOOKING FAR UPSTREAM WE FIND A LARGE AND VIGOROUS UPPER LEVEL LOW SPINNING OVER THE PACIFIC NORTHWEST. MAIN FLOW AROUND THE SOUTHERN PERIPHERY OF THIS CIRCULATION EMERGES THROUGH THE FOUR-CORNERS REGION AND THEN RIDGES UP OVER THE CENTRAL PLAINS. THIS FLOW THEN QUICKLY DIVES BACK TO THE SOUTHEAST AND MERGES WITH AN IMPRESSIVE LONGWAVE TROUGH PIVOTING THROUGH MUCH OF EASTERN CANADA AND THE EASTERN CONUS. OUR FORECAST AREA RESIDES NEAR THE SOUTHERN PERIPHERY/BASE OF THIS EASTERN TROUGH. WV IMAGERY CLEARLY DEFINES A WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WITHIN THE BASE OF THE LONGWAVE TROUGH WHICH WILL PIVOT THROUGH THE REGION THIS MORNING AND EARLY AFTERNOON. BEHIND THIS SHORTWAVE FOR THE SECOND HALF OF THE DAY/EVENING THE DEPTH OF DRY AIR WITHIN THE COLUMN WILL INCREASE (ESPECIALLY OVER THE NORTHERN HALF OF THE AREA AS WEAK NVA AND DEEP LAYER SUBSIDENCE ARRIVES FROM THE WEST AND NORTHWEST. THE PASSAGE OF THIS SHORTWAVE TO OUR EAST BEFORE THE TIME OF PEAK DIURNAL HEATING WILL WORK IN THE FAVOR FOR THOSE LOOKING FOR LESS CONVECTIVE ACTIVITY THAN HAS BEEN SEEN THE PAST COUPLE OF DAYS. STILL UNLIKELY THAT THIS SETUP WILL BE ENOUGH TO COMPLETELY SUPPRESS THE THUNDERSTORM THREAT FOR ALL AREAS. SEEING A FEW FAVORABLE ASPECTS IN THE SHORT TERM FOR UPDRAFT INITIATION AND SUPPORT. WILL BE WATCHING A WEAK LOW LEVEL TROUGH DROP SOUTH TOWARD THE I-10 CORRIDOR EARLY THIS AFTERNOON. LOW LEVEL FOCUS ALONG AND JUST SOUTH OF THIS BOUNDARY MAY BE ENOUGH TO SUPPORT A FEW SHOWERS/STORMS UP TOWARD LEVY COUNTY BY MID AFTERNOON BEFORE THE MORE SIGNIFICANTLY HOSTILE AIR ALOFT TOWARD CONVECTION ARRIVES. LOCAL HIGH-RES WRFARW SIMULATIONS ARE IN FAVOR OF THIS CONVECTIVE DEVELOPMENT...BUT ALSO KEEP THE CONVECTION FAIRLY SHALLOW WITH UPDRAFT RATES THAT ARE GENERALLY UNSUPPORTIVE OF SIGNIFICANT WEATHER. BY THIS EVENING...THETA-E VALUES AROUND 700MB ARE WELL BELOW 320K UP TOWARD CHIEFLAND WHICH WILL MAKE IT VERY DIFFICULT FOR ANY CUMULUS TOWERS ATTEMPTING TO GROW. THE OTHER AREA WE AREA LOOKING FOR WIDELY SCATTERED CONVECTIVE ACTIVITY IS ACROSS OUR INTERIOR SOUTHERN ZONES...MAINLY WELL INLAND FROM I-75. MORE FAVORABLE MOISTURE PROFILES WILL HOLD ON A LITTLE LONGER DOWN TOWARD THESE AREA...AND A RAPID INLAND PROPAGATION OF THE SEA-BREEZE WILL ADD SOME LOWER LEVEL FOCUS. LESS CONVECTIVE ACTIVITY AND 850MB TEMPS OF 16-17C GIVE THE BOUNDARY LAYER A WARM POTENTIAL TODAY. THOSE AREAS NOT SEEING ANY QUICK SHOWER AND AWAY FROM THE BEACHES SHOULD EASILY MIX OUT INTO THE LOWER 90S...WITH WARMER SPOTS PEAKING IN THE MID 90S. ONSHORE FLOW DEVELOPING QUICKLY TODAY WILL HOLD THE BEACHES IN THE 80S. PATTERN SUGGESTS ANY LINGERING STORMS BY MID-EVENING WILL BE OVER TOWARD THE I-95 CORRIDOR WHICH SHOULD SET UP A MAINLY DRY...QUIET AND SEASONABLE OVERNIGHT PERIOD. ENJOY! && .AVIATION... PREVAILING VFR WITH FEW-SCT CLOUDS. LIGHT AND VARIABLE WINDS BECOME WESTERLY LATE MORNING AND AFTERNOON...KEEPING LIMITED TSRA EAST OF THE TERMINALS. && .MARINE... WINDS AND SEAS WILL REMAIN RATHER LIGHT THROUGH TODAY AND TONIGHT. A WEAKENING COLD FRONT WILL SLIDE SOUTHWARD THROUGH THE WATERS FRIDAY AND FRIDAY NIGHT...WITH STRONG HIGH PRESSURE THEN BUILDING NORTH OF THE STATE OVER THE WEEKEND INTO EARLY NEXT WEEK. ELEVATED EASTERLY FLOW WILL LIKELY RESULT IN A NEED FOR EXERCISE CAUTION OR ADVISORY HEADLINES FOR MUCH OF THE MARINE AREA DURING THE EVENING AND OVERNIGHT HOURS EACH DAY THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 73 91 71 / 0 0 0 0 FMY 91 72 91 72 / 10 10 10 10 GIF 92 71 93 68 / 20 10 10 0 SRQ 86 71 89 71 / 0 0 0 0 BKV 90 65 91 63 / 10 0 10 0 SPG 90 75 89 74 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1103 AM CDT THU MAY 23 2013 .DISCUSSION... 240 AM CDT TODAY... FORECAST CHALLENGES FOR TODAY RESIDE WITH HIGH TEMPS...AND PRECIP CHANCES THIS MORNING. IR IMAGERY EARLY THIS MORNING SHOWS CONSIDERABLE CLOUD COVER REMAINING ACROSS THE WESTERN GREAT LAKES...EXTENDING SOUTH THROUGH THE MID-MISSISSIPPI VALLEY. ALONG THE WESTERN PERIPHERY OF THE CLOUD COVER LIES THE LEADING EDGE OF THE STRONG SFC RIDGE...BEGINNING TO PUSH INTO THE UPPER MIDWEST/NORTHERN PLAINS. MOISTURE HAS BEEN CONSISTENTLY PEELING OFF TO THE NORTHEAST...NOTED IN THE STEADILY LOWERING DEW POINTS. DEW POINTS ACROSS CENTRAL WISC HAVE ALREADY FALLEN INTO THE UPR 40S...AND EXPECT THIS TREND TO EVENTUALLY ARRIVE ACROSS NORTHERN IL/NORTHWEST IN. A BROAD SFC TROUGH WAS ANALYZED ACROSS NORTHEAST IL STRETCHING INTO SOUTHCENTRAL LOWER MI. AS A RESULT SFC WINDS ACROSS THE CWFA HAVE MAINLY BEEN FROM THE WEST/SOUTHWEST...HOWEVER JUST NORTH OF THE CWFA INTO WISC WINDS HAVE ALREADY SHIFTED TO THE NORTHWEST/NORTH. LOCATIONS ADJACENT TO LAKE MICHIGAN WILL SEE WINDS FLOP OVER TO THE NORTHEAST THIS MORNING...ALLOWING THE MUCH COOLER MARINE ENVIRONMENT TO READILY FLOW ACROSS THE LAND. REGIONAL RADAR EARLY THIS MORNING SHOWS AN AREA OF SHOWERS ACROSS CENTRAL WISC...SLOWLY SLIDING SOUTHEAST. HI-RES GUIDANCE SUGGESTS THIS CHANNEL OF PRECIP WILL EVENTUALLY ARRIVE ACROSS NORTHERN IL JUST BEFORE DAYBREAK. AS A RESULT OF THE INCREASED CONFIDENCE IN PRECIP...HAVE NUDGED THE 12-15Z TIMEFRAME TO LIKELY POPS FOR FAR NORTHEAST IL. DRY AIR CONTINUES TO POUR INTO THE REGION MID-MORNING...AND SHOULD BRING AN END TO THE PRECIP FROM NORTHWEST TO SOUTHEAST ACROSS THE CWFA BY EARLY THIS AFTERNOON. THE STEADY PUSH OF DRY AIR WILL ALSO AID IN ERODING THE CLOUD COVER...AND BY LATE THIS AFTERNOON EXPECT MOSTLY SUNNY SKIES TO DEVELOP. COLD AIR ADVECTION WILL DOMINATE THE DAY...COUPLED PRECIP AND CLOUDS...EXPECT MUCH COOLER TEMPS FOR THIS AFTERNOON. GUIDANCE HAS CONTINUED TO SUGGEST TEMPS WILL STRUGGLE TO WARM BEYOND THE LOW 60S FOR THE FAR WESTERN CWFA...MEANWHILE FURTHER EAST TEMPS WILL ONLY WARM A FEW DEGREES FROM THEIR STARTING POINT. THIS WILL MOST LIKELY LEAD TO AREAS EAST OF I-39 ONLY WARMING INTO THE MID/UPR 50S. LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN COULD SEE TEMPS STRUGGLE TO WARM BEYOND 50 DEGREES. CONFIDENCE IN PRECIP ENDING TIME...MEDIUM/HIGH. CONFIDENCE IN TEMPERATURES...HIGH. TONIGHT... ANTI-CYCLONIC FLOW WILL CONTINUE TO BUILD OVERHEAD EARLY THIS EVENING...AND ERODE ANY LINGERING CLOUDS BY MIDNIGHT. DEW POINTS AS A RESULT WILL CONTINUE TO DRY...BOTTOMING OUT IN THE MID 30S IN MANY LOCATIONS. THE COMBINATION OF NEAR CLOUDLESS SKIES...LIGHT NORTH TO AT TIMES CALM WINDS...AND RECENT RAINFALL...WILL SET THE STAGE FOR NOT ONLY STRONG RADIATIONAL COOLING BUT PATCHY FROST AWAY FROM LAKE MICHIGAN. GUIDANCE CONTINUES TO PROG TEMPS FALLING OVERNIGHT INTO THE MID/UPR 30S FOR AREAS WEST OF WAUKEGAN TO KANKAKEE. FAR SOUTHERN PORTIONS OF THE CWFA SHOULD HAVE TEMPS HOLD ARND 40 DEGREES OVERNIGHT...HOWEVER A FEW LOW-LYING AREAS COULD SEE SPOTTY FROST. AT THIS POINT IT DOES NOT APPEAR TO BE A WIDESPREAD FROST SETUP...SO WILL HOLD OFF ON ANY HEADLINES AT THIS POINT. CONFIDENCE...HIGH. FRIDAY... SFC HIGH PRESSURE WILL DOMINATE THE REGION FOR THE END OF THE WEEK...AND MORE THAN LIKELY ONLY ALLOW A FEW DIURNAL CLOUDS TO DEVELOP. A LIGHT NORTHEAST FLOW OFF OF LAKE MICHIGAN WILL CONTINUE TO KEEP ADJACENT AREAS MUCH COOLER IN THE MID/UPR 50S...MEANWHILE INLAND LOCATIONS WILL BEGIN TO WARM INTO THE LOW/MID 60S. WITH HIGH PRESSURE STILL IN CONTROL FRIDAY NIGHT...EXPECT ANOTHER NIGHT OF STRONG RADIATIONAL COOLING. THE ONLY DIFFERENCE FOR FRI NIGHT WILL BE THE RIDGE AXIS WILL HAVE SHIFTED EAST. THIS WILL ALLOW THE LIGHT WINDS TO BEGIN TURNING SOUTHEASTERLY AFTER MIDNIGHT...AND COULD SLOW THE RATE OF COOLING. HAVE MAINTAINED TEMPS IN THE LOW 40S FOR MANY AREAS. COULD SEE A FEW OF THE TRADITIONAL COOL SPOTS DIP TO THE UPR 30S EARLY SAT MORNING...HOWEVER AT THIS POINT NOT ANTICIPATING FROST FORMATION. CONFIDENCE IN TEMPERATURES...HIGH. SATURDAY... DISCREPANCIES BEGIN TO EMERGE AMONGST SOLUTIONS FOR SAT...WITH RESPECT TO PLACEMENT/TIMING OF A MOIST BOUNDARY. GFS HAS CONTINUED TO BE THE MORE PROGRESSIVE SOLUTION...BRINGING THIS CHANNEL OF MOISTURE/PRECIP INTO THE REGION AND STRETCHES FROM THE NORTHERN PLAINS SOUTHEAST THROUGH THE OHIO VALLEY. MEANWHILE THE EC HAS MAINTAINED THE SFC RIDGE...AND SUPPRESSING THE MOIST CHANNEL TO THE SOUTHWEST OF THE CWFA. THE LARGEST WEATHER PLAYER IS THE DOWNSTREAM 500MB RIDGE LOCATED ACROSS THE WESTERN ATLANTIC. THIS WILL ACT AS A BLOCK...SLOWING THE DEPARTURE OF THE MID-LVL TROUGH ACROSS THE MID-ATLANTIC REGION. THEN FURTHER UPSTREAM YET ANOTHER 500MB RIDGE WAS PROGGED TO ARRIVE ACROSS THE CENTRAL CONUS...AND DOES SHOW SOME SIGNS OF AMPLIFICATION. BASED ON THIS SETUP IT IS BECOMING MORE EVIDENT THAT SAT COULD END UP BEING DRY...AND POSSIBLY EXTEND INTO SUN. AT THIS POINT HAVE ONLY ADJUSTED POPS SAT MARGINALLY...TO SLIGHT CHANCE WORDING. SFC TEMPS WILL REMAIN UNSEASONABLY COOL IN THE LOW/MID 60S...WITH AREAS ADJACENT TO LAKE MICHIGAN BEING EVEN COOLER THAN THIS. DESPITE THE EXPECTED SOUTHEAST COMPONENT TO THE SFC WINDS...ENOUGH HEATING COULD ALLOW A LAKE BREEZE TO FORM AND ALLOW WINDS TO BECOME MORE EASTERLY FOR LOCATIONS ADJACENT TO LAKE MICHIGAN. THIS WILL MOST LIKELY RESULT IN THOSE AREAS IMMEDIATELY NEXT TO THE LAKE REMAINING IN THE 50S SAT AFTN. CONFIDENCE...MEDIUM. SUNDAY THROUGH WEDNESDAY... FOR THE EXTENDED PERIODS GUIDANCE HAS CONTINUED TO DEMONSTRATE MINIMAL CHANGES FROM PREVIOUS SOLUTIONS...HOWEVER OPERATIONAL ECMWF/GFS CONTINUE TO DIFFER ON THE PLACEMENT/TIMING OF PRECIP. THE ECMWF CONTINUES TO SUGGEST THE SFC RIDGE FROM LATE IN THE WEEK WILL HOLD TOUGH AND KEEP NORTHERN IL/NORTHWEST IN DRY THRU THE WEEKEND AND INTO EARLY NEXT WEEK. MEANWHILE THE GFS IS STILL MORE PROGRESSIVE AND BRINGS THE BOUNDARY OVERHEAD AND BECOMES QUASI-STATIONARY THRU THE FIRST HALF OF NEXT WEEK. ENSEMBLES CONTINUE TO INDICATE THE WESTERN ATLANTIC MID-LVL RIDGE WILL WEAKEN...ALLOWING THE 500MB TROUGH TO FINALLY EJECT EAST. IN ADDITION THE UPSTREAM RIDGE WILL BEGIN TO FLATTEN...LEADING TO A SOMEWHAT PROGRESSIVE FLOW OF SYSTEMS FROM WEST TO EAST TOWARDS THE MIDDLE OF NEXT WEEK. THUS PRECIP CHC WILL BE ON THE INCREASE TOWARDS THE FINAL FEW PERIODS OF THE CURRENT EXTENDED FORECAST. BY TUE/WED OF NEXT WEEK...TEMPS COULD EASILY BE BACK INTO THE UPR 70S TO LOW 80S. CONFIDENCE IN PRECIPITATION...LOW. CONFIDENCE IN TEMPERATURES...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * VARIABLE MVFR/IFR CIG SLOWLY IMPROVING AOA 1500 FT AROUND 17Z. VFR/CLEARING BY MID AFTN. * NORTH WIND WITH GUSTS TO AROUND 30 KT CONTINUING THROUGH AFTN. ALLSOPP/BMD //DISCUSSION...UPDATED 12Z... MAIN CONCERN THIS MORNING IS CIG TRENDS...THEN THIS AFTERNOON FOCUS WILL BE ON STRONG GUSTY NNE WINDS. LOW PRESSURE WAS OVER THE EASTERN GREAT LAKES WITH A COLD FRONT TRAILING WESTWARD INTO NORTHERN IL. AT 11Z THE FRONT WAS FROM ABOUT IKK-VYS. BASED ON NAM AND HRRR MODEL SOUNDINGS...CIGS SHOULD SLOWLY IMPROVE TO AROUND 1000-1200 FT IN THE NEXT COUPLE HOURS. THIS SEEMS REASONABLE WITH STRONGER WINDS MIXING COLDER AND SLIGHTLY DRIER AIR DOWN FROM THE NORTH. ALSO SPOTTY LIGHT RAIN/DRIZZLE WILL BE DIMINISHING/MOVING OUT AND THAT MAY ALSO HELP IMPROVE CIG AND VSBY A BIT THIS MORNING. AS OF 11Z THE BACK EDGE OF THE MAIN BAND OF RAIN ASSOCIATED WITH THE COLD FRONT WAS LINED UP FROM DKB-DPA- MDW-GYY AND SINKING VERY SLOWLY S. THERE WERE SOME VSBY RESTRICTIONS DOWN TO 2-3 MILES IN THIS BAND OF RAIN...BUT IT HAS PUSHED SOUTH OF THE TERMINALS. FURTHER NORTH INTO SOUTHERN WI THERE WERE SOME PATCHES OF LIGHT RAIN/DRIZZLE..BUT THIS WAS VERY LIGHT. SHORT RANGE/HI RES MODELS SUGGEST THIS SPOTTY LIGHT RAIN WILL BE DRYING UP AND MOVING SE OUT OF THE AREA BY MID TO LATE MORNING. THEREFORE DONT EXPECT ANY SIGNIFICANT VSBY RESTRICTIONS BELOW 5 OR 6 MILES THE REST OF THE MORNING. AS STRONG NORTH WINDS CONTINUE TO PUSH COLDER DRIER AIR DOWN...EXPECT CLOUDS TO LIFT TO 1500 FT OR BETTER BY NOON AND BREAK UP THIS AFTERNOON WITH CLEARING MID TO LATE AFTN. NORTH WINDS HAVE PICKED UP AND WINDS WILL CONTINUE TO INCREASE TO 20 TO 30 KT BY MID MORNING. DIRECTION MAY VARY SOME FROM 350-030 BUT WILL BE PREDOMINANTLY JUST E OF N TODAY. PRESSURE GRADIENT SLOWLY BEGINS TO RELAX LATE THIS AFTERNOON AND WINDS MAY DIMINISH SLIGHTLY DURING THE LATE AFTN. ATMOSPHERE SHOULD BEGIN TO DECOUPLE THIS EVENING AS PRESSURE GRADIENT CONTINUES TO RELAX. OUTLOOK FOR FRIDAY IS VFR WITH LIGHT NORTHEAST WINDS. ALLSOPP //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH CONFIDENCE IN CIG TRENDS THIS MORNING. * MEDIUM CONFIDENCE IN TIMING OF CLEARING THIS AFTN. * HIGH CONFIDENCE IN WIND FORECAST. DIRECTION MAY VARY FROM 350-030. ALLSOPP/BMD //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. WX NIL. SUNDAY AND MONDAY...VFR. CHC SHRA SLIGHT CHC TSRA. TUESDAY AND WEDNESDAY...CHC TSRA. ALLSOPP && .MARINE... 147 AM CDT EARLY THURSDAY MORNING AN ELONGATED AREA OF LOW PRESSURE WAS FROM THE EASTERN GREAT LAKES BACK TO NORTHERN ILLINOIS...WHILE A STRONG AREA OF HIGH PRESSURE WAS CENTERED OVER NORTHERN MANITOBA WITH A RIDGE EXTENDING SOUTHWARD INTO THE NORTHERN PLAINS. AS THE TROF SWINGS EAST AND THE RIDGE BUILDS INTO THE WESTERN GREAT LAKES TODAY...GALE FORCE NORTH WINDS WILL DEVELOP OVER LAKE MICHIGAN. THE GALES WILL DEVELOP OVER CENTRAL LAKE MICHIGAN EARLY THIS MORNING AND SPREAD TO THE SOUTH END BY MID OR LATE MORNING. WINDS WILL DIMINISH OVERNIGHT AS THE HIGH SETTLES OVER THE WESTERN GREAT LAKES AND THE LOW MOVES UP THE EAST COAST. THE HIGH WILL THEN BE NEARLY STATIONARY OVER THE GREAT LAKES THROUGH THE WEEKEND WITH LIGHT EAST TO SOUTHEAST FLOW OVER THE LAKE. LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI VALLEY MONDAY AND TUESDAY WHICH WILL CAUSE WINDS TO BECOME SOUTHERLY OVER LAKE MICHIGAN. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ872-LMZ874-LMZ876- LMZ878 UNTIL 9 PM THURSDAY. GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ868-LMZ870 UNTIL 3 PM THURSDAY. && $$ 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
907 AM CDT THU MAY 23 2013 .DISCUSSION... 240 AM CDT TODAY... FORECAST CHALLENGES FOR TODAY RESIDE WITH HIGH TEMPS...AND PRECIP CHANCES THIS MORNING. IR IMAGERY EARLY THIS MORNING SHOWS CONSIDERABLE CLOUD COVER REMAINING ACROSS THE WESTERN GREAT LAKES...EXTENDING SOUTH THROUGH THE MID-MISSISSIPPI VALLEY. ALONG THE WESTERN PERIPHERY OF THE CLOUD COVER LIES THE LEADING EDGE OF THE STRONG SFC RIDGE...BEGINNING TO PUSH INTO THE UPPER MIDWEST/NORTHERN PLAINS. MOISTURE HAS BEEN CONSISTENTLY PEELING OFF TO THE NORTHEAST...NOTED IN THE STEADILY LOWERING DEW POINTS. DEW POINTS ACROSS CENTRAL WISC HAVE ALREADY FALLEN INTO THE UPR 40S...AND EXPECT THIS TREND TO EVENTUALLY ARRIVE ACROSS NORTHERN IL/NORTHWEST IN. A BROAD SFC TROUGH WAS ANALYZED ACROSS NORTHEAST IL STRETCHING INTO SOUTHCENTRAL LOWER MI. AS A RESULT SFC WINDS ACROSS THE CWFA HAVE MAINLY BEEN FROM THE WEST/SOUTHWEST...HOWEVER JUST NORTH OF THE CWFA INTO WISC WINDS HAVE ALREADY SHIFTED TO THE NORTHWEST/NORTH. LOCATIONS ADJACENT TO LAKE MICHIGAN WILL SEE WINDS FLOP OVER TO THE NORTHEAST THIS MORNING...ALLOWING THE MUCH COOLER MARINE ENVIRONMENT TO READILY FLOW ACROSS THE LAND. REGIONAL RADAR EARLY THIS MORNING SHOWS AN AREA OF SHOWERS ACROSS CENTRAL WISC...SLOWLY SLIDING SOUTHEAST. HI-RES GUIDANCE SUGGESTS THIS CHANNEL OF PRECIP WILL EVENTUALLY ARRIVE ACROSS NORTHERN IL JUST BEFORE DAYBREAK. AS A RESULT OF THE INCREASED CONFIDENCE IN PRECIP...HAVE NUDGED THE 12-15Z TIMEFRAME TO LIKELY POPS FOR FAR NORTHEAST IL. DRY AIR CONTINUES TO POUR INTO THE REGION MID-MORNING...AND SHOULD BRING AN END TO THE PRECIP FROM NORTHWEST TO SOUTHEAST ACROSS THE CWFA BY EARLY THIS AFTERNOON. THE STEADY PUSH OF DRY AIR WILL ALSO AID IN ERODING THE CLOUD COVER...AND BY LATE THIS AFTERNOON EXPECT MOSTLY SUNNY SKIES TO DEVELOP. COLD AIR ADVECTION WILL DOMINATE THE DAY...COUPLED PRECIP AND CLOUDS...EXPECT MUCH COOLER TEMPS FOR THIS AFTERNOON. GUIDANCE HAS CONTINUED TO SUGGEST TEMPS WILL STRUGGLE TO WARM BEYOND THE LOW 60S FOR THE FAR WESTERN CWFA...MEANWHILE FURTHER EAST TEMPS WILL ONLY WARM A FEW DEGREES FROM THEIR STARTING POINT. THIS WILL MOST LIKELY LEAD TO AREAS EAST OF I-39 ONLY WARMING INTO THE MID/UPR 50S. LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN COULD SEE TEMPS STRUGGLE TO WARM BEYOND 50 DEGREES. CONFIDENCE IN PRECIP ENDING TIME...MEDIUM/HIGH. CONFIDENCE IN TEMPERATURES...HIGH. TONIGHT... ANTI-CYCLONIC FLOW WILL CONTINUE TO BUILD OVERHEAD EARLY THIS EVENING...AND ERODE ANY LINGERING CLOUDS BY MIDNIGHT. DEW POINTS AS A RESULT WILL CONTINUE TO DRY...BOTTOMING OUT IN THE MID 30S IN MANY LOCATIONS. THE COMBINATION OF NEAR CLOUDLESS SKIES...LIGHT NORTH TO AT TIMES CALM WINDS...AND RECENT RAINFALL...WILL SET THE STAGE FOR NOT ONLY STRONG RADIATIONAL COOLING BUT PATCHY FROST AWAY FROM LAKE MICHIGAN. GUIDANCE CONTINUES TO PROG TEMPS FALLING OVERNIGHT INTO THE MID/UPR 30S FOR AREAS WEST OF WAUKEGAN TO KANKAKEE. FAR SOUTHERN PORTIONS OF THE CWFA SHOULD HAVE TEMPS HOLD ARND 40 DEGREES OVERNIGHT...HOWEVER A FEW LOW-LYING AREAS COULD SEE SPOTTY FROST. AT THIS POINT IT DOES NOT APPEAR TO BE A WIDESPREAD FROST SETUP...SO WILL HOLD OFF ON ANY HEADLINES AT THIS POINT. CONFIDENCE...HIGH. FRIDAY... SFC HIGH PRESSURE WILL DOMINATE THE REGION FOR THE END OF THE WEEK...AND MORE THAN LIKELY ONLY ALLOW A FEW DIURNAL CLOUDS TO DEVELOP. A LIGHT NORTHEAST FLOW OFF OF LAKE MICHIGAN WILL CONTINUE TO KEEP ADJACENT AREAS MUCH COOLER IN THE MID/UPR 50S...MEANWHILE INLAND LOCATIONS WILL BEGIN TO WARM INTO THE LOW/MID 60S. WITH HIGH PRESSURE STILL IN CONTROL FRIDAY NIGHT...EXPECT ANOTHER NIGHT OF STRONG RADIATIONAL COOLING. THE ONLY DIFFERENCE FOR FRI NIGHT WILL BE THE RIDGE AXIS WILL HAVE SHIFTED EAST. THIS WILL ALLOW THE LIGHT WINDS TO BEGIN TURNING SOUTHEASTERLY AFTER MIDNIGHT...AND COULD SLOW THE RATE OF COOLING. HAVE MAINTAINED TEMPS IN THE LOW 40S FOR MANY AREAS. COULD SEE A FEW OF THE TRADITIONAL COOL SPOTS DIP TO THE UPR 30S EARLY SAT MORNING...HOWEVER AT THIS POINT NOT ANTICIPATING FROST FORMATION. CONFIDENCE IN TEMPERATURES...HIGH. SATURDAY... DISCREPANCIES BEGIN TO EMERGE AMONGST SOLUTIONS FOR SAT...WITH RESPECT TO PLACEMENT/TIMING OF A MOIST BOUNDARY. GFS HAS CONTINUED TO BE THE MORE PROGRESSIVE SOLUTION...BRINGING THIS CHANNEL OF MOISTURE/PRECIP INTO THE REGION AND STRETCHES FROM THE NORTHERN PLAINS SOUTHEAST THROUGH THE OHIO VALLEY. MEANWHILE THE EC HAS MAINTAINED THE SFC RIDGE...AND SUPPRESSING THE MOIST CHANNEL TO THE SOUTHWEST OF THE CWFA. THE LARGEST WEATHER PLAYER IS THE DOWNSTREAM 500MB RIDGE LOCATED ACROSS THE WESTERN ATLANTIC. THIS WILL ACT AS A BLOCK...SLOWING THE DEPARTURE OF THE MID-LVL TROUGH ACROSS THE MID-ATLANTIC REGION. THEN FURTHER UPSTREAM YET ANOTHER 500MB RIDGE WAS PROGGED TO ARRIVE ACROSS THE CENTRAL CONUS...AND DOES SHOW SOME SIGNS OF AMPLIFICATION. BASED ON THIS SETUP IT IS BECOMING MORE EVIDENT THAT SAT COULD END UP BEING DRY...AND POSSIBLY EXTEND INTO SUN. AT THIS POINT HAVE ONLY ADJUSTED POPS SAT MARGINALLY...TO SLIGHT CHANCE WORDING. SFC TEMPS WILL REMAIN UNSEASONABLY COOL IN THE LOW/MID 60S...WITH AREAS ADJACENT TO LAKE MICHIGAN BEING EVEN COOLER THAN THIS. DESPITE THE EXPECTED SOUTHEAST COMPONENT TO THE SFC WINDS...ENOUGH HEATING COULD ALLOW A LAKE BREEZE TO FORM AND ALLOW WINDS TO BECOME MORE EASTERLY FOR LOCATIONS ADJACENT TO LAKE MICHIGAN. THIS WILL MOST LIKELY RESULT IN THOSE AREAS IMMEDIATELY NEXT TO THE LAKE REMAINING IN THE 50S SAT AFTN. CONFIDENCE...MEDIUM. SUNDAY THROUGH WEDNESDAY... FOR THE EXTENDED PERIODS GUIDANCE HAS CONTINUED TO DEMONSTRATE MINIMAL CHANGES FROM PREVIOUS SOLUTIONS...HOWEVER OPERATIONAL ECMWF/GFS CONTINUE TO DIFFER ON THE PLACEMENT/TIMING OF PRECIP. THE ECMWF CONTINUES TO SUGGEST THE SFC RIDGE FROM LATE IN THE WEEK WILL HOLD TOUGH AND KEEP NORTHERN IL/NORTHWEST IN DRY THRU THE WEEKEND AND INTO EARLY NEXT WEEK. MEANWHILE THE GFS IS STILL MORE PROGRESSIVE AND BRINGS THE BOUNDARY OVERHEAD AND BECOMES QUASI-STATIONARY THRU THE FIRST HALF OF NEXT WEEK. ENSEMBLES CONTINUE TO INDICATE THE WESTERN ATLANTIC MID-LVL RIDGE WILL WEAKEN...ALLOWING THE 500MB TROUGH TO FINALLY EJECT EAST. IN ADDITION THE UPSTREAM RIDGE WILL BEGIN TO FLATTEN...LEADING TO A SOMEWHAT PROGRESSIVE FLOW OF SYSTEMS FROM WEST TO EAST TOWARDS THE MIDDLE OF NEXT WEEK. THUS PRECIP CHC WILL BE ON THE INCREASE TOWARDS THE FINAL FEW PERIODS OF THE CURRENT EXTENDED FORECAST. BY TUE/WED OF NEXT WEEK...TEMPS COULD EASILY BE BACK INTO THE UPR 70S TO LOW 80S. CONFIDENCE IN PRECIPITATION...LOW. CONFIDENCE IN TEMPERATURES...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * VARIABLE MVFR/IFR CIG SLOWLY IMPROVING AOA 1500 FT AROUND 17Z. VFR/CLEARING BY MID AFTN. * NORTH WIND INCREASING TO 20 TO 30 KT BY MID MORNING AND CONTINUING THROUGH AFTN. ALLSOPP/BMD //DISCUSSION...UPDATED 12Z... MAIN CONCERN THIS MORNING IS CIG TRENDS...THEN THIS AFTERNOON FOCUS WILL BE ON STRONG GUSTY NNE WINDS. LOW PRESSURE WAS OVER THE EASTERN GREAT LAKES WITH A COLD FRONT TRAILING WESTWARD INTO NORTHERN IL. AT 11Z THE FRONT WAS FROM ABOUT IKK-VYS. BASED ON NAM AND HRRR MODEL SOUNDINGS...CIGS SHOULD SLOWLY IMPROVE TO AROUND 1000-1200 FT IN THE NEXT COUPLE HOURS. THIS SEEMS REASONABLE WITH STRONGER WINDS MIXING COLDER AND SLIGHTLY DRIER AIR DOWN FROM THE NORTH. ALSO SPOTTY LIGHT RAIN/DRIZZLE WILL BE DIMINISHING/MOVING OUT AND THAT MAY ALSO HELP IMPROVE CIG AND VSBY A BIT THIS MORNING. AS OF 11Z THE BACK EDGE OF THE MAIN BAND OF RAIN ASSOCIATED WITH THE COLD FRONT WAS LINED UP FROM DKB-DPA- MDW-GYY AND SINKING VERY SLOWLY S. THERE WERE SOME VSBY RESTRICTIONS DOWN TO 2-3 MILES IN THIS BAND OF RAIN...BUT IT HAS PUSHED SOUTH OF THE TERMINALS. FURTHER NORTH INTO SOUTHERN WI THERE WERE SOME PATCHES OF LIGHT RAIN/DRIZZLE..BUT THIS WAS VERY LIGHT. SHORT RANGE/HI RES MODELS SUGGEST THIS SPOTTY LIGHT RAIN WILL BE DRYING UP AND MOVING SE OUT OF THE AREA BY MID TO LATE MORNING. THEREFORE DONT EXPECT ANY SIGNIFICANT VSBY RESTRICTIONS BELOW 5 OR 6 MILES THE REST OF THE MORNING. AS STRONG NORTH WINDS CONTINUE TO PUSH COLDER DRIER AIR DOWN...EXPECT CLOUDS TO LIFT TO 1500 FT OR BETTER BY NOON AND BREAK UP THIS AFTERNOON WITH CLEARING MID TO LATE AFTN. NORTH WINDS HAVE PICKED UP AND WINDS WILL CONTINUE TO INCREASE TO 20 TO 30 KT BY MID MORNING. DIRECTION MAY VARY SOME FROM 350-030 BUT WILL BE PREDOMINANTLY JUST E OF N TODAY. PRESSURE GRADIENT SLOWLY BEGINS TO RELAX LATE THIS AFTERNOON AND WINDS MAY DIMINISH SLIGHTLY DURING THE LATE AFTN. ATMOSPHERE SHOULD BEGIN TO DECOUPLE THIS EVENING AS PRESSURE GRADIENT CONTINUES TO RELAX. OUTLOOK FOR FRIDAY IS VFR WITH LIGHT NORTHEAST WINDS. ALLSOPP //ORD AND MDW CONFIDENCE...UPDATED 12Z... * LOW/MEDIUM CONFIDENCE IN CIG TRENDS THIS MORNING. * MEDIUM CONFIDENCE IN TIMING OF CLEARING THIS AFTN. * HIGH CONFIDENCE IN WIND FORECAST. DIRECTION MAY VARY FROM 350-030 BUT SHOULD STAY JUST E OF N. ALLSOPP //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. WX NIL. SUNDAY AND MONDAY...VFR. CHC SHRA SLIGHT CHC TSRA. TUESDAY AND WEDNESDAY...CHC TSRA. ALLSOPP && .MARINE... 147 AM CDT EARLY THURSDAY MORNING AN ELONGATED AREA OF LOW PRESSURE WAS FROM THE EASTERN GREAT LAKES BACK TO NORTHERN ILLINOIS...WHILE A STRONG AREA OF HIGH PRESSURE WAS CENTERED OVER NORTHERN MANITOBA WITH A RIDGE EXTENDING SOUTHWARD INTO THE NORTHERN PLAINS. AS THE TROF SWINGS EAST AND THE RIDGE BUILDS INTO THE WESTERN GREAT LAKES TODAY...GALE FORCE NORTH WINDS WILL DEVELOP OVER LAKE MICHIGAN. THE GALES WILL DEVELOP OVER CENTRAL LAKE MICHIGAN EARLY THIS MORNING AND SPREAD TO THE SOUTH END BY MID OR LATE MORNING. WINDS WILL DIMINISH OVERNIGHT AS THE HIGH SETTLES OVER THE WESTERN GREAT LAKES AND THE LOW MOVES UP THE EAST COAST. THE HIGH WILL THEN BE NEARLY STATIONARY OVER THE GREAT LAKES THROUGH THE WEEKEND WITH LIGHT EAST TO SOUTHEAST FLOW OVER THE LAKE. LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI VALLEY MONDAY AND TUESDAY WHICH WILL CAUSE WINDS TO BECOME SOUTHERLY OVER LAKE MICHIGAN. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ872-LMZ874-LMZ876- LMZ878 UNTIL 9 PM THURSDAY. GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ868-LMZ870 UNTIL 3 PM THURSDAY. && $$ 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
648 AM CDT THU MAY 23 2013 .DISCUSSION... 240 AM CDT TODAY... FORECAST CHALLENGES FOR TODAY RESIDE WITH HIGH TEMPS...AND PRECIP CHANCES THIS MORNING. IR IMAGERY EARLY THIS MORNING SHOWS CONSIDERABLE CLOUD COVER REMAINING ACROSS THE WESTERN GREAT LAKES...EXTENDING SOUTH THROUGH THE MID-MISSISSIPPI VALLEY. ALONG THE WESTERN PERIPHERY OF THE CLOUD COVER LIES THE LEADING EDGE OF THE STRONG SFC RIDGE...BEGINNING TO PUSH INTO THE UPPER MIDWEST/NORTHERN PLAINS. MOISTURE HAS BEEN CONSISTENTLY PEELING OFF TO THE NORTHEAST...NOTED IN THE STEADILY LOWERING DEW POINTS. DEW POINTS ACROSS CENTRAL WISC HAVE ALREADY FALLEN INTO THE UPR 40S...AND EXPECT THIS TREND TO EVENTUALLY ARRIVE ACROSS NORTHERN IL/NORTHWEST IN. A BROAD SFC TROUGH WAS ANALYZED ACROSS NORTHEAST IL STRETCHING INTO SOUTHCENTRAL LOWER MI. AS A RESULT SFC WINDS ACROSS THE CWFA HAVE MAINLY BEEN FROM THE WEST/SOUTHWEST...HOWEVER JUST NORTH OF THE CWFA INTO WISC WINDS HAVE ALREADY SHIFTED TO THE NORTHWEST/NORTH. LOCATIONS ADJACENT TO LAKE MICHIGAN WILL SEE WINDS FLOP OVER TO THE NORTHEAST THIS MORNING...ALLOWING THE MUCH COOLER MARINE ENVIRONMENT TO READILY FLOW ACROSS THE LAND. REGIONAL RADAR EARLY THIS MORNING SHOWS AN AREA OF SHOWERS ACROSS CENTRAL WISC...SLOWLY SLIDING SOUTHEAST. HI-RES GUIDANCE SUGGESTS THIS CHANNEL OF PRECIP WILL EVENTUALLY ARRIVE ACROSS NORTHERN IL JUST BEFORE DAYBREAK. AS A RESULT OF THE INCREASED CONFIDENCE IN PRECIP...HAVE NUDGED THE 12-15Z TIMEFRAME TO LIKELY POPS FOR FAR NORTHEAST IL. DRY AIR CONTINUES TO POUR INTO THE REGION MID-MORNING...AND SHOULD BRING AN END TO THE PRECIP FROM NORTHWEST TO SOUTHEAST ACROSS THE CWFA BY EARLY THIS AFTERNOON. THE STEADY PUSH OF DRY AIR WILL ALSO AID IN ERODING THE CLOUD COVER...AND BY LATE THIS AFTERNOON EXPECT MOSTLY SUNNY SKIES TO DEVELOP. COLD AIR ADVECTION WILL DOMINATE THE DAY...COUPLED PRECIP AND CLOUDS...EXPECT MUCH COOLER TEMPS FOR THIS AFTERNOON. GUIDANCE HAS CONTINUED TO SUGGEST TEMPS WILL STRUGGLE TO WARM BEYOND THE LOW 60S FOR THE FAR WESTERN CWFA...MEANWHILE FURTHER EAST TEMPS WILL ONLY WARM A FEW DEGREES FROM THEIR STARTING POINT. THIS WILL MOST LIKELY LEAD TO AREAS EAST OF I-39 ONLY WARMING INTO THE MID/UPR 50S. LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN COULD SEE TEMPS STRUGGLE TO WARM BEYOND 50 DEGREES. CONFIDENCE IN PRECIP ENDING TIME...MEDIUM/HIGH. CONFIDENCE IN TEMPERATURES...HIGH. TONIGHT... ANTI-CYCLONIC FLOW WILL CONTINUE TO BUILD OVERHEAD EARLY THIS EVENING...AND ERODE ANY LINGERING CLOUDS BY MIDNIGHT. DEW POINTS AS A RESULT WILL CONTINUE TO DRY...BOTTOMING OUT IN THE MID 30S IN MANY LOCATIONS. THE COMBINATION OF NEAR CLOUDLESS SKIES...LIGHT NORTH TO AT TIMES CALM WINDS...AND RECENT RAINFALL...WILL SET THE STAGE FOR NOT ONLY STRONG RADIATIONAL COOLING BUT PATCHY FROST AWAY FROM LAKE MICHIGAN. GUIDANCE CONTINUES TO PROG TEMPS FALLING OVERNIGHT INTO THE MID/UPR 30S FOR AREAS WEST OF WAUKEGAN TO KANKAKEE. FAR SOUTHERN PORTIONS OF THE CWFA SHOULD HAVE TEMPS HOLD ARND 40 DEGREES OVERNIGHT...HOWEVER A FEW LOW-LYING AREAS COULD SEE SPOTTY FROST. AT THIS POINT IT DOES NOT APPEAR TO BE A WIDESPREAD FROST SETUP...SO WILL HOLD OFF ON ANY HEADLINES AT THIS POINT. CONFIDENCE...HIGH. FRIDAY... SFC HIGH PRESSURE WILL DOMINATE THE REGION FOR THE END OF THE WEEK...AND MORE THAN LIKELY ONLY ALLOW A FEW DIURNAL CLOUDS TO DEVELOP. A LIGHT NORTHEAST FLOW OFF OF LAKE MICHIGAN WILL CONTINUE TO KEEP ADJACENT AREAS MUCH COOLER IN THE MID/UPR 50S...MEANWHILE INLAND LOCATIONS WILL BEGIN TO WARM INTO THE LOW/MID 60S. WITH HIGH PRESSURE STILL IN CONTROL FRIDAY NIGHT...EXPECT ANOTHER NIGHT OF STRONG RADIATIONAL COOLING. THE ONLY DIFFERENCE FOR FRI NIGHT WILL BE THE RIDGE AXIS WILL HAVE SHIFTED EAST. THIS WILL ALLOW THE LIGHT WINDS TO BEGIN TURNING SOUTHEASTERLY AFTER MIDNIGHT...AND COULD SLOW THE RATE OF COOLING. HAVE MAINTAINED TEMPS IN THE LOW 40S FOR MANY AREAS. COULD SEE A FEW OF THE TRADITIONAL COOL SPOTS DIP TO THE UPR 30S EARLY SAT MORNING...HOWEVER AT THIS POINT NOT ANTICIPATING FROST FORMATION. CONFIDENCE IN TEMPERATURES...HIGH. SATURDAY... DISCREPANCIES BEGIN TO EMERGE AMONGST SOLUTIONS FOR SAT...WITH RESPECT TO PLACEMENT/TIMING OF A MOIST BOUNDARY. GFS HAS CONTINUED TO BE THE MORE PROGRESSIVE SOLUTION...BRINGING THIS CHANNEL OF MOISTURE/PRECIP INTO THE REGION AND STRETCHES FROM THE NORTHERN PLAINS SOUTHEAST THROUGH THE OHIO VALLEY. MEANWHILE THE EC HAS MAINTAINED THE SFC RIDGE...AND SUPPRESSING THE MOIST CHANNEL TO THE SOUTHWEST OF THE CWFA. THE LARGEST WEATHER PLAYER IS THE DOWNSTREAM 500MB RIDGE LOCATED ACROSS THE WESTERN ATLANTIC. THIS WILL ACT AS A BLOCK...SLOWING THE DEPARTURE OF THE MID-LVL TROUGH ACROSS THE MID-ATLANTIC REGION. THEN FURTHER UPSTREAM YET ANOTHER 500MB RIDGE WAS PROGGED TO ARRIVE ACROSS THE CENTRAL CONUS...AND DOES SHOW SOME SIGNS OF AMPLIFICATION. BASED ON THIS SETUP IT IS BECOMING MORE EVIDENT THAT SAT COULD END UP BEING DRY...AND POSSIBLY EXTEND INTO SUN. AT THIS POINT HAVE ONLY ADJUSTED POPS SAT MARGINALLY...TO SLIGHT CHANCE WORDING. SFC TEMPS WILL REMAIN UNSEASONABLY COOL IN THE LOW/MID 60S...WITH AREAS ADJACENT TO LAKE MICHIGAN BEING EVEN COOLER THAN THIS. DESPITE THE EXPECTED SOUTHEAST COMPONENT TO THE SFC WINDS...ENOUGH HEATING COULD ALLOW A LAKE BREEZE TO FORM AND ALLOW WINDS TO BECOME MORE EASTERLY FOR LOCATIONS ADJACENT TO LAKE MICHIGAN. THIS WILL MOST LIKELY RESULT IN THOSE AREAS IMMEDIATELY NEXT TO THE LAKE REMAINING IN THE 50S SAT AFTN. CONFIDENCE...MEDIUM. SUNDAY THROUGH WEDNESDAY... FOR THE EXTENDED PERIODS GUIDANCE HAS CONTINUED TO DEMONSTRATE MINIMAL CHANGES FROM PREVIOUS SOLUTIONS...HOWEVER OPERATIONAL ECMWF/GFS CONTINUE TO DIFFER ON THE PLACEMENT/TIMING OF PRECIP. THE ECMWF CONTINUES TO SUGGEST THE SFC RIDGE FROM LATE IN THE WEEK WILL HOLD TOUGH AND KEEP NORTHERN IL/NORTHWEST IN DRY THRU THE WEEKEND AND INTO EARLY NEXT WEEK. MEANWHILE THE GFS IS STILL MORE PROGRESSIVE AND BRINGS THE BOUNDARY OVERHEAD AND BECOMES QUASI-STATIONARY THRU THE FIRST HALF OF NEXT WEEK. ENSEMBLES CONTINUE TO INDICATE THE WESTERN ATLANTIC MID-LVL RIDGE WILL WEAKEN...ALLOWING THE 500MB TROUGH TO FINALLY EJECT EAST. IN ADDITION THE UPSTREAM RIDGE WILL BEGIN TO FLATTEN...LEADING TO A SOMEWHAT PROGRESSIVE FLOW OF SYSTEMS FROM WEST TO EAST TOWARDS THE MIDDLE OF NEXT WEEK. THUS PRECIP CHC WILL BE ON THE INCREASE TOWARDS THE FINAL FEW PERIODS OF THE CURRENT EXTENDED FORECAST. BY TUE/WED OF NEXT WEEK...TEMPS COULD EASILY BE BACK INTO THE UPR 70S TO LOW 80S. CONFIDENCE IN PRECIPITATION...LOW. CONFIDENCE IN TEMPERATURES...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * IFR CIG SLOWLY IMPROVING TO MVFR AROUND 12-14Z...AND AOA 1500 FT BY NOON. VFR/CLEARING BY MID AFTN. * NORTH WIND INCREASING TO 20 TO 30 KT BY MID MORNING AND CONTINUING THROUGH AFTN. ALLSOPP //DISCUSSION...UPDATED 12Z... MAIN CONCERN THIS MORNING IS CIG TRENDS...THEN THIS AFTERNOON FOCUS WILL BE ON STRONG GUSTY NNE WINDS. LOW PRESSURE WAS OVER THE EASTERN GREAT LAKES WITH A COLD FRONT TRAILING WESTWARD INTO NORTHERN IL. AT 11Z THE FRONT WAS FROM ABOUT IKK-VYS. BASED ON NAM AND HRRR MODEL SOUNDINGS...CIGS SHOULD SLOWLY IMPROVE TO AROUND 1000-1200 FT IN THE NEXT COUPLE HOURS. THIS SEEMS REASONABLE WITH STRONGER WINDS MIXING COLDER AND SLIGHTLY DRIER AIR DOWN FROM THE NORTH. ALSO SPOTTY LIGHT RAIN/DRIZZLE WILL BE DIMINISHING/MOVING OUT AND THAT MAY ALSO HELP IMPROVE CIG AND VSBY A BIT THIS MORNING. AS OF 11Z THE BACK EDGE OF THE MAIN BAND OF RAIN ASSOCIATED WITH THE COLD FRONT WAS LINED UP FROM DKB-DPA- MDW-GYY AND SINKING VERY SLOWLY S. THERE WERE SOME VSBY RESTRICTIONS DOWN TO 2-3 MILES IN THIS BAND OF RAIN...BUT IT HAS PUSHED SOUTH OF THE TERMINALS. FURTHER NORTH INTO SOUTHERN WI THERE WERE SOME PATCHES OF LIGHT RAIN/DRIZZLE..BUT THIS WAS VERY LIGHT. SHORT RANGE/HI RES MODELS SUGGEST THIS SPOTTY LIGHT RAIN WILL BE DRYING UP AND MOVING SE OUT OF THE AREA BY MID TO LATE MORNING. THEREFORE DONT EXPECT ANY SIGNIFICANT VSBY RESTRICTIONS BELOW 5 OR 6 MILES THE REST OF THE MORNING. AS STRONG NORTH WINDS CONTINUE TO PUSH COLDER DRIER AIR DOWN...EXPECT CLOUDS TO LIFT TO 1500 FT OR BETTER BY NOON AND BREAK UP THIS AFTERNOON WITH CLEARING MID TO LATE AFTN. NORTH WINDS HAVE PICKED UP AND WINDS WILL CONTINUE TO INCREASE TO 20 TO 30 KT BY MID MORNING. DIRECTION MAY VARY SOME FROM 350-030 BUT WILL BE PREDOMINANTLY JUST E OF N TODAY. PRESSURE GRADIENT SLOWLY BEGINS TO RELAX LATE THIS AFTERNOON AND WINDS MAY DIMINISH SLIGHTLY DURING THE LATE AFTN. ATMOSPHERE SHOULD BEGIN TO DECOUPLE THIS EVENING AS PRESSURE GRADIENT CONTINUES TO RELAX. OUTLOOK FOR FRIDAY IS VFR WITH LIGHT NORTHEAST WINDS. ALLSOPP //ORD AND MDW CONFIDENCE...UPDATED 12Z... * MEDIUM CONFIDENCE IN CIG TRENDS THIS MORNING. * MEDIUM CONFIDENCE IN TIMING OF CLEARING THIS AFTN. * HIGH CONFIDENCE IN WIND FORECAST. DIRECTION MAY VARY FROM 350-030 BUT SHOULD STAY JUST E OF N. ALLSOPP //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. WX NIL. SUNDAY AND MONDAY...VFR. CHC SHRA SLIGHT CHC TSRA. TUESDAY AND WEDNESDAY...CHC TSRA. ALLSOPP && .MARINE... 147 AM CDT EARLY THURSDAY MORNING AN ELONGATED AREA OF LOW PRESSURE WAS FROM THE EASTERN GREAT LAKES BACK TO NORTHERN ILLINOIS...WHILE A STRONG AREA OF HIGH PRESSURE WAS CENTERED OVER NORTHERN MANITOBA WITH A RIDGE EXTENDING SOUTHWARD INTO THE NORTHERN PLAINS. AS THE TROF SWINGS EAST AND THE RIDGE BUILDS INTO THE WESTERN GREAT LAKES TODAY...GALE FORCE NORTH WINDS WILL DEVELOP OVER LAKE MICHIGAN. THE GALES WILL DEVELOP OVER CENTRAL LAKE MICHIGAN EARLY THIS MORNING AND SPREAD TO THE SOUTH END BY MID OR LATE MORNING. WINDS WILL DIMINISH OVERNIGHT AS THE HIGH SETTLES OVER THE WESTERN GREAT LAKES AND THE LOW MOVES UP THE EAST COAST. THE HIGH WILL THEN BE NEARLY STATIONARY OVER THE GREAT LAKES THROUGH THE WEEKEND WITH LIGHT EAST TO SOUTHEAST FLOW OVER THE LAKE. LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI VALLEY MONDAY AND TUESDAY WHICH WILL CAUSE WINDS TO BECOME SOUTHERLY OVER LAKE MICHIGAN. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ872-LMZ874-LMZ876- LMZ878 UNTIL 9 PM THURSDAY. GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ868-LMZ870 UNTIL 3 PM THURSDAY. && $$ 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 TOPEKA KS
312 AM CDT THU MAY 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 230 AM CDT THU MAY 23 2013 THE OLD UPPER SYSTEM CONTINUES TO SLIDE EAST AND WEAKEN OVER THE WESTERN GREAT LAKES...WITH 0Z 500MB HEIGHT CHANGE OBSERVATIONS DEPICTING WEAK TO MODERATE RISES ACROSS THE PLAINS. LOW LEVEL RIDGING WAS TAKING SHAPE ACROSS THE CENTRAL PLAINS...WITH SOUTH WINDS TAKING HOLD OVER THE SOUTHERN HIGH PLAINS. A SHRINKING STRATUS DECK WAS OOZING SOUTH THROUGH NEBRASKA EARLY THIS MORNING. SHALLOW NATURE TO THE LOW CLOUDS AND INCREASING LOW LEVEL ISENTROPIC DOWNGLIDE SHOULD ALLOW THE INVADING STRATUS TO DISSIPATE THIS MORNING THOUGH MORE COULD REDEVELOP WITH DAYTIME HEATING. TEMPS AGAIN STAY ON THE COOL SIDE WITH NORTH WINDS VEERING TO THE EAST THROUGH THE DAY. FURTHER VEERING ON TRACK FOR TONIGHT AS LEE LOW PRESSURE BEGINS TO TAKE SHAPE AND UPPER HEIGHTS CONTINUE TO RISE. MID LEVEL MOISTURE INCREASES A BIT IN THE WEST WITH MODEST ISENTROPIC UPGLIDE VIA WEAK WINDS AND ELEVATED CAPE DEVELOPING. THIS COULD BE ENOUGH TO USHER ANY HIGH PLAINS CONVECTION INTO NORTH CENTRAL KANSAS LATE TONIGHT...THOUGH CONFIDENCE IN THE FORMER MAKING IT THIS FAR NORTH IS NOT VERY HIGH. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 230 AM CDT THU MAY 23 2013 DESPITE THE FACT THAT THERE ARE CHANCES FOR PRECIPITATION THROUGH THE FORECAST FOR FRIDAY THROUGH NEXT WEDNESDAY...REST ASSURED IT WONT BE RAINING ALL DAY EVERY DAY. CONVECTION IS BEING DRIVEN BY SMALL WAVES IN THE FLOW THAT ARE DIFFICULT TO TIME...BY THE NOCTURNAL LLJ...AS WELL AS THE BOUNDARIES THAT THE CONVECTION LEAVES BEHIND TO REGENERATE CHANCES FOR THE FOLLOWING DAY...AND OTHER MESOSCALE INTERACTIONS RELATED TO ALL THESE FEATURES. WILL LIKELY BE ABLE TO TIME PRECIPITATION CHANCES BETTER IN A WINDOW CLOSER TO THEIR TIME SCALES...BY A MATTER OF A DAY OR TWO RATHER THAN SEVERAL DAYS OUT. FIRST FEATURE IS A FRONTAL BOUNDARY DRAPED N/S FROM THE DAKOTAS INTO NEBRASKA...THE SOUTHERN EDGE OF WHICH CLIPS ACROSS THE FORECAST AREA THROUGH THE DAY ON FRIDAY. THE FOLLOWING NIGHT LLJ SLIDES CONVECTION ALONG THE NORTH AND TO THE NE OF THE CWA AND MAY RUN THROUGH OUR NORTHERN COUNTIES. BOUNDARY FROM THIS MCS COULD THEN LAY UP ACROSS THE AREA ON SATURDAY AFTERNOON AND REGENERATE STORMS...WITH YET ANOTHER WEAK WAVE RIDING ACROSS WRN/CTRL KS AND BRINGING ANOTHER CHANCE FOR TS SATURDAY NIGHT INTO SUNDAY MORNING. MAY CATCH A BREAK BETWEEN WAVES ON SUNDAY AFTERNOON BEFORE POTENTIAL FOR ANOTHER WAVE TO LIFT ACROSS THE WRN THRU NORTHERN COUNTIES INTO MONDAY. SOME SUGGESTION THAT RIDGE AMPLIFIES TUESDAY INTO WEDNESDAY IN THE ECMWF...ALTHOUGH GFS AMPLIFIES IT FARTHER TO THE EAST OF OUR FA AND KEEPS THE DAMP PATTERN GOING FOR ANOTHER DAY. AFTER A COOLER DAY IN THE 70S ON FRIDAY...AS SFC RIDGE SHIFTS EAST AND WAA RETURNS...SHOULD SE A SHIFT BACK TOWARD THE LOWER 80S FOR HIGHS ACROSS THE AREA. IF THE RIDGE CAN AMPLIFY...MAY SEE WARMER TEMPS TOWARD LATER NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1122 PM CDT WED MAY 22 2013 THE RAP AND NAM CONTINUE TO SHOW THE POTENTIAL FOR MVFR CIGS MOVING IN FROM THE NORTH BY 12Z. THEREFORE FORECAST THINKING IS UNCHANGED. CIGS SHOULD GRADUALLY IMPROVE BY NOON WITH THE POTENTIAL FOR A STRATOCU DECK PERSISTING THROUGH A GOOD PORTION OF THE DAY. SFC WINDS WILL GRADUALLY VEER WITH RIDGING NOSING IN. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
104 AM CDT THU MAY 23 2013 ...AVIATION SECTION UPDATED FOR 06Z TAFS... .SYNOPSIS... ISSUED AT 340 PM CDT WED MAY 22 2013 THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 340 PM CDT WED MAY 22 2013 THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING. THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT. ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER COULD REACH THE LOW/MID 70S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 348 PM CDT WED MAY 22 2013 LOW LEVEL MOISTURE WILL SURGE BACK TO THE NORTHWEST INTO THE SOUTHERN PLAINS BY LATE THURSDAY AS UPPER LEVEL TROUGHING DEVELOPS ACROSS THE WESTERN UNITED STATES. SURGE HIGH PRESSURE WILL SLIDE SOUTHEASTWARD INTO THE MIDWEST. A WARM ADVECTION PATTERN WILL STRENGTHEN THURSDAY NIGHT AND SOME ELEVATED THUNDERSTORM ACTIVITY IS POSSIBLE. THE UPPER LEVEL RIDGE AXIS BETWEEN THE WESTERN AND EASTERN UNITED STATES TROUGHS WILL BE OVER THE CENTRAL PLAINS BY FRIDAY. BUT SOME MID LEVEL FLOW COMING THROUGH THE RIDGE WILL ALLOW FOR LEE TROUGHING AND A SURGE OF MOISTURE FROM THE SOUTHERN PLAINS INTO KANSAS. WESTERN KANSAS WILL BE ON THE SOUTHERN EDGE OF THE WESTERLIES AND THE UPPER LEVEL WINDS WILL NOT BE THAT IMPRESSIVE. HOWEVER, WITH 2000-3000 J/KG CAPE AND STRONG DIRECTIONAL TURNING, A FEW SEVERE THUNDERSTORMS ARE POSSIBLE, PARTICULARLY IN FAR SOUTHWEST KANSAS. HIGH TEMPERATURES FRIDAY WILL RANGE FROM THE UPPER 70S NEAR HAYS TO THE UPPER 80S IN FAR SOUTHWEST KANSAS CLOSER TO THE LEE TROUGH. UPPER LEVEL TROUGHING WILL REMAIN ACROSS THE WESTERN UNITED STATES THROUGH MID NEXT WEEK, ALTHOUGH THERE IS SOME UNCERTAINTY IN HOW FAR EAST IT WILL PROGRESS. THE ECMWF IS LESS PROGRESSIVE THAN THE OTHER MODELS AND GENERALLY A LESS PROGRESSIVE SOLUTION IS THE BEST ONE. FOR SATURDAY INTO MONDAY, MODERATE TO HIGH SURFACE BASED CAPE WILL BE IN PLACE AHEAD OF A DRYLINE. A FEW THUNDERSTORMS WILL DEVELOP EACH DAY ALONG THE DRYLINE AND SLOWLY MOVE EASTWARD. THESE STORMS COULD BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE UPPER LEVEL WINDS ARE STILL NOT PROGGED TO BE THAT STRONG, SO TORNADIC STORMS ARE NOT EXPECTED, BUT CANNOT BE RULED OUT GIVEN THE STRONG INSTABILITY. TEMPERATURES WILL BE FAIRLY WARM THROUGH THE EXTENDED WITH LOWS IN THE 60S AND HIGHS IN THE 80S AND 90S SINCE KANSAS WILL BE IN THE WARM SECTOR. THE WARMEST HIGH TEMPERATURES OUGHT TO BE IN FAR WESTERN KANSAS BEHIND THE DRYLINE AND THE WARMEST LOWS SHOULD BE IN SOUTH CENTRAL AND CENTRAL KANSAS WHERE DEWPOINTS AND WINDS WILL BE HIGHEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1257 AM CDT THU MAY 23 2013 A COLD FRONT WILL SLIDE INTO THE HAYS AREA BY 10Z AND INTO GCK AND DDC BY 12Z. AT THE SAME TIME A WARM FRONT ACROSS WEST AND CENTRAL TEXAS WILL LIFT NORTH INTO THE TX PANHANDLE DURING THE OVERNIGHT PERIOD. MOISTENING EASTERLY WINDS HAVE COMMENCED AND WILL BE REINFORCED BEHIND THE AFOREMENTIONED COLD FRONT. THERE WAS ALREADY STRATUS BEHIND THE FRONT AND AS THE SURFACE FLOW MOVES WEST INTO HIGHER TERRAIN STRATUS WILL BEGIN TO FORM SOUTH OF THE FRONT BY SUNRISE. INITIAL THINKING IS MVFR CEILINGS MAY BE REACHED AT HYS BY 12Z BUT SHOULD REMAIN HIGHER AT DDC/GCK. I`VE LEFT PCPN OUT OF THE TERMINALS FOR NOW BUT WILL WATCH FOR ELEVATED DEVELOPMENT EARLY THIS MORNING AS HIGH RESOLUTION FORECAST MODELS SHOW SOME ACTIVITY BY SUNRISE AROUND HAYS. && .PRELIMINARY POINT TEMPS/POPS... DDC 58 81 63 89 / 40 30 30 30 GCK 58 83 63 91 / 30 40 40 20 EHA 59 88 63 92 / 30 40 30 20 LBL 60 87 64 91 / 30 40 30 20 HYS 56 77 67 89 / 40 40 30 40 P28 59 78 67 86 / 30 40 30 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GERARD SHORT TERM...GERARD LONG TERM...FINCH AVIATION...HUTTON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1122 PM CDT WED MAY 22 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 354 PM CDT WED MAY 22 2013 THE UPPER LOW ASSOCIATED WITH THIS WEEKEND`S ACTIVE SEVERE WEATHER WAS SITUATED OVER IOWA THIS AFTERNOON...WITH THE ASSOCIATED SURFACE LOW PROGRESSING EASTWARD INTO WISCONSIN AND ILLINOIS. CLOUD COVER IN ASSOCIATION WITH THIS SYSTEM STRETCHED WESTWARD INTO NORTHEAST AND FAR EASTERN KANSAS THROUGH THE AFTERNOON HOURS...WHICH RESULTED IN SOMEWHAT COOLER TEMPERATURES ACROSS THE REGION TODAY. WITH THE CLOUD COVER...AFTERNOON HIGHS PEAKED IN THE MIDDLE TO UPPER 60S. SURFACE HIGH PRESSURE OVER THE NORTHERN PLAINS WILL HELP TO PUSH THE LOW PRESSURE SYSTEM EASTWARD TOWARD THE GREAT LAKES REGION AS THE HIGH SPREADS SOUTHWARD INTO THE CENTRAL PLAINS TONIGHT INTO THURSDAY. WITH THE EXITING SURFACE LOW...SHOULD START SEEING SOME BREAKS IN THE CLOUD COVER TONIGHT INTO THE OVERNIGHT HOURS. THIS DIMINISHING CLOUD COVER WILL ALLOW FOR MORE RADIATIONAL COOLING EARLY THURSDAY MORNING WITH LOW TEMPERATURES EXPECTED TO BE A FEW DEGREES COOLER THAN NORMAL...IN THE UPPER 40S TO LOWER 50S. THE WEAK UPPER LEVEL RIDGE THAT WAS IN PLACE OVER THE CENTRAL ROCKIES THIS AFTERNOON WILL CONTINUE TO BUILD AS IT PROGRESSES EASTWARD INTO THE CENTRAL AND SOUTHERN PLAINS BY THURSDAY. MODELS CONTINUE TO SHOW AN EMBEDDED SHORTWAVE DEVELOPING ALONG THE NORTHERN EXTENT OF THE RIDGE OVER WESTERN KANSAS AND WESTERN OKLAHOMA...WHICH MAY BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS TO THAT REGION THROUGH THE DAY. WHILE THIS ACTIVITY IS EXPECTED TO REMAIN SOUTHWEST OF THE FORECAST AREA ON THURSDAY...SHOULD STILL HAVE SCATTERED CLOUD COVER ACROSS MUCH OF THE AREA THROUGH THE DAY. THIS CLOUD COVER COMBINED WITH NORTHEASTERLY WINDS AROUND THE SURFACE HIGH WILL KEEP AFTERNOON HIGHS COOLER THAN NORMAL WITH READINGS LIKING PEAKING IN THE UPPER 60S TO LOWER 70S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 354 PM CDT WED MAY 22 2013 OVERALL PATTERN WILL FEATURE A FLAT RIDGE WITH INCREASING WAA AND MOISTURE ADVECTION WHICH WILL SERVE TO PRODUCE SEVERAL BOUTS OF THUNDERSTORM CHCS. THE INITIAL FORCING IS WEAK THU NIGHT INTO FRI AND SHOULD STAY FOCUSED ACROSS THE NORTHWEST PARTS OF THE CWA. WILL KEEP RAIN CHCS LOW AND CONFINED TO AREAS TOPEKA NORTH AND WEST FOR FRI BUT AGAIN WITHOUT A FOCUS AND GREATER FORCING NOT SURE HOW WIDESPREAD ANY PRECIP WILL BE FRI. BY FRI NIGHT INTO SAT THETA-E (MOISTURE AND TEMP ADVECTION) WILL INCREASE ACROSS KS INTO NEBRASKA. NOSE OF THE 50KT LLJ WILL TARGET NORTHEAST NEB SO IT WOULD APPEAR THAT THE MAIN COMPLEX OF ANY MCS WOULD BE LOCATED NORTH OF THE AREA HOWEVER CANNOT RULE OUT SCT CONVECTION WITHIN THE LLJ AXIS OVERNIGHT INTO EARLY SAT. ANOTHER WEAK WAVE WILL MOVE ACROSS THE RIDGE SAT NIGHT INTO SUN AND THIS SHOULD HELP ANOTHER CONVECTIVE COMPLEX DEVELOP ACROSS NE/NORTHERN KS SO WILL KEEP 20 TO 40 POPS WITH THE HIGHEST ACROSS THE NORTHERN COUNTIES. SAME PATTERN WILL PERSIST INTO SUN NIGHT AND MON SO HAVE TO EXPECT AT LEAST SOME CHCS FOR MAINLY NIGHTTIME THUNDERSTORMS ACROSS THE AREA SUN NIGHT AND MON AS WEAK WAVES MOVE INTO THE FLATTENING RIDGE AND COMBINE WITH THE NIGHTTIME LLJ TO FEED OVERNIGHT STORMS. MON AND BEYOND...IT APPEARS THAT RIDGING SHOULD STRENGTHEN BY TUES AHEAD OF A DEEPENING TROUGH ACROSS THE WEST. THIS SHOULD LEAD TO GRADUALLY WARMER TEMPS AND PERHAPS A LULL IN PRECIP CHCS BY MID WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1122 PM CDT WED MAY 22 2013 THE RAP AND NAM CONTINUE TO SHOW THE POTENTIAL FOR MVFR CIGS MOVING IN FROM THE NORTH BY 12Z. THEREFORE FORECAST THINKING IS UNCHANGED. CIGS SHOULD GRADUALLY IMPROVE BY NOON WITH THE POTENTIAL FOR A STRATOCU DECK PERSISTING THROUGH A GOOD PORTION OF THE DAY. SFC WINDS WILL GRADUALLY VEER WITH RIDGING NOSING IN. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HENNECKE LONG TERM...OMITT AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS GRAY ME
1035 PM EDT FRI MAY 24 2013 .SYNOPSIS... A COLD FRONT WILL PUSH OFFSHORE AND STALL THIS EVENING. LOW PRESSURE WILL DEVELOP ON THE FRONT NEAR CAPE COD AND WILL SLOWLY DRIFT NORTH THROUGH THE GULF OF MAINE SATURDAY AND SATURDAY NIGHT. LOW PRESSURE WILL ACCELERATE NORTH INTO LABRADOR ON SUNDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST SUNDAY NIGHT THROUGH MONDAY. HIGH PRESSURE WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY AND WILL PUSH EAST OF THE REGION WEDNESDAY NIGHT. && .NEAR TERM /THROUGH SATURDAY/... UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS...WITH THE COLD FRONT NOW HAVING SLIPPED SOUTH OF THE COAST WATERS AS OF 0230Z. LOW PRESSURE WILL CONTINUE TO TAKE SHAPE OFF THE NEW ENG COASTLINE THEREAFTER...WITH CYCLOGENESIS OCCURRING NEAR CAPE COD THIS EVENING. LATEST HRRR MODEL PICKING UP WELL ON CONVECTIVE SEGMENTS CROSSING THE FORECAST AREA AT THIS TIME. THIS MODEL DEPICTS MORE AREAS OF RAIN MOVING THROUGH THE REGION LATE TONIGHT AND SATURDAY MORNING. WILL CONTINUE TO MONITOR COLD AIR RUSHING INTO THE MTNS FROM CANADA OVERNIGHT. THERE COULD BE SOME MIXED SNOW AND RAIN OVER THE HIGHER TERRAIN FOR THIS STORM WHICH IS VERY SIMILAR TO THE MAY 26TH 1967 EVENT. HAVE ADJUSTED WINDS AND TEMPS FOR THE HIGHER TERRAIN. WINDS WILL BECOME RATHER GUSTY FOR ANY HIKERS OUT OF THE NORTH AND NORTH OVER THE NEXT COUPLE OF DAYS...WITH SOME SNOW ACROSS THE HIGH TERRAIN. PREV DISC... COLD FRONT CURRENTLY MOVING EAST THROUGH EASTERN NEW HAMPSHIRE AND NORTHWEST MAINE AND THIS BOUNDARY WILL CONTINUE TO PUSH OFF TO THE EAST THROUGH THE REMAINDER OF THE AFTERNOON. FRONT WILL STALL OFFSHORE THIS EVENING AND WILL BE THE FOCUS OF LIGHT TO MODERATE RAINFALL IN MID COAST AND CENTRAL MAINE DURING THE REMAINDER OF THE AFTERNOON INTO THIS EVENING. WILL SEE A BRIEF BREAK IN THE ACTION ACROSS NEW HAMPSHIRE DURING THE REST OF THE AFTERNOON BEFORE NEXT BATCH OF PRECIP EDGES IN FROM THE WEST. WILL TAKE SOME TIME FOR LOW PRESSURE TO GET SPUN UP OVERNIGHT SO THIS BREAK MAY TRANSLATE EASTWARD INTO WESTERN MAINE FOR THE EVENING HOURS BEFORE 850 OVER-RUNNING GETS GOING IN EARNEST ACROSS WESTERN MAINE AFTER MIDNIGHT. 12Z MODELS TRENDING FARTHER WEST WITH AXIS OF HEAVIEST PRECIP AND COMING INTO LINE WITH LAST NIGHT 00Z ECMWF. 24 HOUR QPF FOR THE MOUNTAINS AND CONNECTICUT VALLEY DOWN TO AROUND AN INCH TO 1.5 INCHES THROUGH 00Z SUN. WITH THIS IN MIND...DOESN`T APPEAR FLOODING WILL BE AN ISSUE CONSIDERING THE BREAK IN THE ACTION THIS AFTERNOON AND LONG DURATION OF THE EVENT ITSELF...SO HOLDING OFF ON ANY WATCHES AT THIS POINT IN TIME. && .SHORT TERM /SATURDAY NIGHT/... RAIN WILL CONTINUE SATURDAY THROUGH SATURDAY NIGHT AS SURFACE LOW BECOMES TRAPPED UNDER UPPER LEVEL SYSTEM AND MEANDERS AROUND THE GULF OF MAINE THROUGH SUNDAY MORNING. MAY SEE SOME WET SNOW OVER THE HIGHEST TERRAIN AT SOME POINT ON SATURDAY IN FAR WESTERN ZONES BUT ENOUGH WARM AIR WRAPS AROUND THE SYSTEM THAT THIS WOULD BE FAIRLY BRIEF. BETTER CHANCE FOR THIS WOULD BE IN THE GREENS OF VERMONT AND THE DACKS. WILL BE A COLD AND BLUSTERY DAY WITH TEMPS HOLDING IN THE 40S IN MOST AREAS AND SHOWING LITTLE CHANGE SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... UPR LVL AND SFC LOWS LIFTING NE ON SUNDAY WITH STEADIER PRCP BECOMING MORE SCT IN NATURE AND LIGHTER IN INTENSITY. ANY LEFTOVER SHRA ENDING SUNDAY NGT AS THE SYSTEM MOVES INTO THE MARITIMES. MEMORIAL DAY LOOKS LIKE FAIR WX NOW WITH SYSTEM PULLING OUT FAR ENOUGH TO THE NE. STILL SOME CYCLONIC FLOW ALOFT AND SOME LEFTOVER MOISTURE THAT COULD PRODUCE SOME CLOUDINESS ESPECIALLY IN THE N/MT ZONES DUE TO UPSLOPING NW SFC WINDS. MIGHT SEE AN ISOLD SHRA IN THE N/MT ZONES OTRW NO PRCP EXPECTED ON MEMORIAL DAY. HIGH PRES AND UPR LVL RIDGE BUILD IN FOR TUESDAY INTO WEDNESDAY. THE UPR LVL RIDGE HOLDS 0N OVER THE ERN U.S. BUT A SERIES OF WEAK UPR LVL SHORT WAVE TROFS DRIVE THRU THE RIDGE FOR LATE WEDNESDAY AND THURSDAY. THIS FORMS A WRM FRONTAL BOUNDARY TO OUR S THAT LIFTS N AND WILL PROVIDE SOME CLOUDINESS AND ISOLD TO SCT SHRA FROM LATE WEDNESDAY THRU THURSDAY. THE UPR LVL RIDGE BECOMES BETTER ESTABLISHED OVER THE E COAST THURSDAY NGT AND FRIDAY AS THE SHORT WAVES EXIT THE COAST. THIS SHOULD ALLOW WRM AIR TO CONT MOVING IN FROM THE SW. STILL CAN`T RULE OUT PSBL SHRA DUE TO WRM FNT MOVING THRU. GENERALLY USED BLEND OF GFS40/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5 THEN GFS40, GMOS, HPC QPF, MEX MOS AND WNA4 FOR THE REST OF THE LONG TERM FCST. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM...IFR/LIFR CEILINGS TONIGHT THROUGH SATURDAY NIGHT. LONG TERM /SUNDAY THROUGH WEDNESDAY/...MVFR TO PSBL IFR IN SHRA THAT WILL BE TAPERING OFF SUNDAY INTO SUNDAY NGT. MAINLY VFR MONDAY THRU TUESDAY AND MOST OF WEDNESDAY. && .MARINE... SHORT TERM...HAVE EXTENDED SCA TO GO RIGHT THROUGH SATURDAY. ALTHOUGH WINDS DROP OFF AT SOME POINT...WAVES WILL REMAIN AT LEAST IN THE 3 TO 5 FOOT RANGE...WITH GREATER SEAS OUT OVER THE OPEN WATERS. COASTAL FLOOD ADVISORY FOR MINOR SPLASH-OVER AROUND THE TIME OF HIGH TIDE. LONG TERM /SUNDAY THROUGH WEDNESDAY/...SCA WIND GUSTS AND SEAS PSBL SUNDAY THRU MOST OF SUNDAY NGT THEN HIGH PRES DROPS CONDITIONS BELOW SCA LEVELS MONDAY THRU WEDNESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .COASTAL SPLASH-OVER... VERY MINOR EFFECTS AROUND THE TIME OF HIGH TIDE WHICH WILL OCCUR SHORTLY. .GYX WATCHES/WARNINGS/ADVISORIES... ME...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MEZ023>028. NH...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NHZ014. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150>154. && $$ JC
AREA FORECAST DISCUSSION
NWS GRAY ME
804 PM EDT FRI MAY 24 2013 .SYNOPSIS... A COLD FRONT WILL PUSH OFFSHORE AND STALL THIS EVENING. LOW PRESSURE WILL DEVELOP ON THE FRONT NEAR CAPE COD AND WILL SLOWLY DRIFT NORTH THROUGH THE GULF OF MAINE SATURDAY AND SATURDAY NIGHT. LOW PRESSURE WILL ACCELERATE NORTH INTO LABRADOR ON SUNDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST SUNDAY NIGHT THROUGH MONDAY. HIGH PRESSURE WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY AND WILL PUSH EAST OF THE REGION WEDNESDAY NIGHT. && .NEAR TERM /THROUGH SATURDAY/... UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS...WITH THE COLD FRONT SLIPPING THROUGH THE COAST WATERS AS OF 00Z. LOW PRESSURE WILL CONTINUE TO TAKE SHAPE OFF THE NEW ENG COASTLINE THEREAFTER...WITH CYCLOGENESIS OCCURRING NEAR CAPE COD THIS EVENING. LATEST HRRR MODEL PICKING UP WELL ON CONVECTIVE SEGMENTS CROSSING THE FORECAST AREA AT THIS TIME. THIS MODEL DEPICTS MORE AREAS OF RAIN MOVING THROUGH THE REGION LATE TONIGHT AFTER A BREAK IN THE ACTION LATER THIS EVENING. WILL CONTINUE TO MONITOR COLD AIR RUSHING INTO THE MTNS FROM CANADA OVERNIGHT. THERE COULD BE SOME MIXED SNOW AND RAIN OVER THE HIGHER TERRAIN FOR THIS STORM WHICH IS VERY SIMILAR TO THE MAY 26TH 1967 EVENT. HAVE ADJUSTED WINDS AND TEMPS FOR THE HIGHER TERRAIN. WINDS WILL BECOME RATHER GUSTY FOR ANY HIKERS OUT OF THE NORTH AND NORTH OVER THE NEXT COUPLE OF DAYS...WITH SOME SNOW ACROSS THE HIGH TERRAIN. PREV DISC... COLD FRONT CURRENTLY MOVING EAST THROUGH EASTERN NEW HAMPSHIRE AND NORTHWEST MAINE AND THIS BOUNDARY WILL CONTINUE TO PUSH OFF TO THE EAST THROUGH THE REMAINDER OF THE AFTERNOON. FRONT WILL STALL OFFSHORE THIS EVENING AND WILL BE THE FOCUS OF LIGHT TO MODERATE RAINFALL IN MID COAST AND CENTRAL MAINE DURING THE REMAINDER OF THE AFTERNOON INTO THIS EVENING. WILL SEE A BRIEF BREAK IN THE ACTION ACROSS NEW HAMPSHIRE DURING THE REST OF THE AFTERNOON BEFORE NEXT BATCH OF PRECIP EDGES IN FROM THE WEST. WILL TAKE SOME TIME FOR LOW PRESSURE TO GET SPUN UP OVERNIGHT SO THIS BREAK MAY TRANSLATE EASTWARD INTO WESTERN MAINE FOR THE EVENING HOURS BEFORE 850 OVER-RUNNING GETS GOING IN EARNEST ACROSS WESTERN MAINE AFTER MIDNIGHT. 12Z MODELS TRENDING FARTHER WEST WITH AXIS OF HEAVIEST PRECIP AND COMING INTO LINE WITH LAST NIGHT 00Z ECMWF. 24 HOUR QPF FOR THE MOUNTAINS AND CONNECTICUT VALLEY DOWN TO AROUND AN INCH TO 1.5 INCHES THROUGH 00Z SUN. WITH THIS IN MIND...DOESN`T APPEAR FLOODING WILL BE AN ISSUE CONSIDERING THE BREAK IN THE ACTION THIS AFTERNOON AND LONG DURATION OF THE EVENT ITSELF...SO HOLDING OFF ON ANY WATCHES AT THIS POINT IN TIME. && .SHORT TERM /SATURDAY NIGHT/... RAIN WILL CONTINUE SATURDAY THROUGH SATURDAY NIGHT AS SURFACE LOW BECOMES TRAPPED UNDER UPPER LEVEL SYSTEM AND MEANDERS AROUND THE GULF OF MAINE THROUGH SUNDAY MORNING. MAY SEE SOME WET SNOW OVER THE HIGHEST TERRAIN AT SOME POINT ON SATURDAY IN FAR WESTERN ZONES BUT ENOUGH WARM AIR WRAPS AROUND THE SYSTEM THAT THIS WOULD BE FAIRLY BRIEF. BETTER CHANCE FOR THIS WOULD BE IN THE GREENS OF VERMONT AND THE DACKS. WILL BE A COLD AND BLUSTERY DAY WITH TEMPS HOLDING IN THE 40S IN MOST AREAS AND SHOWING LITTLE CHANGE SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... UPR LVL AND SFC LOWS LIFTING NE ON SUNDAY WITH STEADIER PRCP BECOMING MORE SCT IN NATURE AND LIGHTER IN INTENSITY. ANY LEFTOVER SHRA ENDING SUNDAY NGT AS THE SYSTEM MOVES INTO THE MARITIMES. MEMORIAL DAY LOOKS LIKE FAIR WX NOW WITH SYSTEM PULLING OUT FAR ENOUGH TO THE NE. STILL SOME CYCLONIC FLOW ALOFT AND SOME LEFTOVER MOISTURE THAT COULD PRODUCE SOME CLOUDINESS ESPECIALLY IN THE N/MT ZONES DUE TO UPSLOPING NW SFC WINDS. MIGHT SEE AN ISOLD SHRA IN THE N/MT ZONES OTRW NO PRCP EXPECTED ON MEMORIAL DAY. HIGH PRES AND UPR LVL RIDGE BUILD IN FOR TUESDAY INTO WEDNESDAY. THE UPR LVL RIDGE HOLDS 0N OVER THE ERN U.S. BUT A SERIES OF WEAK UPR LVL SHORT WAVE TROFS DRIVE THRU THE RIDGE FOR LATE WEDNESDAY AND THURSDAY. THIS FORMS A WRM FRONTAL BOUNDARY TO OUR S THAT LIFTS N AND WILL PROVIDE SOME CLOUDINESS AND ISOLD TO SCT SHRA FROM LATE WEDNESDAY THRU THURSDAY. THE UPR LVL RIDGE BECOMES BETTER ESTABLISHED OVER THE E COAST THURSDAY NGT AND FRIDAY AS THE SHORT WAVES EXIT THE COAST. THIS SHOULD ALLOW WRM AIR TO CONT MOVING IN FROM THE SW. STILL CAN`T RULE OUT PSBL SHRA DUE TO WRM FNT MOVING THRU. GENERALLY USED BLEND OF GFS40/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5 THEN GFS40, GMOS, HPC QPF, MEX MOS AND WNA4 FOR THE REST OF THE LONG TERM FCST. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM...IFR/LIFR CEILINGS TONIGHT THROUGH SATURDAY NIGHT. LONG TERM /SUNDAY THROUGH WEDNESDAY/...MVFR TO PSBL IFR IN SHRA THAT WILL BE TAPERING OFF SUNDAY INTO SUNDAY NGT. MAINLY VFR MONDAY THRU TUESDAY AND MOST OF WEDNESDAY. && .MARINE... SHORT TERM...HAVE EXTENDED SCA TO GO RIGHT THROUGH SATURDAY. ALTHOUGH WINDS DROP OFF AT SOME POINT...WAVES WILL REMAIN AT LEAST IN THE 3 TO 5 FOOT RANGE...WITH GREATER SEAS OUT OVER THE OPEN WATERS. COASTAL FLOOD ADVISORY FOR MINOR SPLASH-OVER AROUND THE TIME OF HIGH TIDE. LONG TERM /SUNDAY THROUGH WEDNESDAY/...SCA WIND GUSTS AND SEAS PSBL SUNDAY THRU MOST OF SUNDAY NGT THEN HIGH PRES DROPS CONDITIONS BELOW SCA LEVELS MONDAY THRU WEDNESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MEZ023>028. NH...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NHZ014. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150>154. && $$ JC
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
937 PM EDT FRI MAY 24 2013 .SYNOPSIS... DRY AND COOL WEATHER CAN BE EXPECTED FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... WINDS ARE WEAKENING QUICKLY AS SURFACE HIGH BUILDS IN A BIT FASTER THAN MODELS DEPICTED. SUBSIDENCE AND DRY AIR CONTINUE TO ERODE THE CLOUD COVER FROM WEST TO EAST. STILL DIFFICULT TO TIME EXACTLY WILL USE LATEST RAP MODEL RUN AS GUIDANCE. PREVIOUS DISCUSSION... THE UPPER LEVEL TROUGH WILL CONTINUE TO PIVOT ACROSS THE REGION THROUGH THE AFTERNOON AND EVENING AS HIGH PRESSURE TRIES TO BUILD OVERHEAD AT THE SURFACE. COLD NORTHWEST FLOW CONTINUES TO KEEP CLOUD COVER OVER MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON...WHICH IS RIGHT IN LINE WITH THE LATEST RUC FORECAST. WITH CLOUD COVER STILL IN PLACE...CONTINUED A DOWNWARD TREND IN THE HIGH TEMPERATURES FOR THE AFTERNOON...WITH PIT LIKELY TO BE VERY CLOSE TO BREAKING IT`S LOW HIGH TEMPERATURES RECORD FROM 1877. THE MOST RECENT MODEL RUNS CONTINUE TO SUGGEST THAT CLOUDS WILL EVENTUALLY DIMINISH OVER THE ENTIRE REGION...LASTING LONGEST IN THE RIDGES. HOW FAST THE CLOUDS DIMINISH WILL PLAY A BIG ROLE IN HOW QUICKLY TEMPERATURES DROP OVERNIGHT. HOWEVER...SINCE TEMPERATURES ARE ALREADY LOWER THAN ORIGINALLY FORECAST...CLEARING SKIES SHOULD ALLOW LOWS IN THE LOW TO MID 30`S TO BE REALIZED RELATIVELY QUICKLY. FOR NOW...CONTINUED THE FROST/FREEZE AS IS...ALTHOUGH SOME COUNTIES MAY NEED TO BE UPGRADED TO A FREEZE IF SKIES CLEAR SOONER AND WINDS DECOUPLE. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY BRINGING A CLEAR DAY BUT NORTHWEST FLOW WILL KEEP TEMPERATURES 10 TO 15 BELOW SEASONAL AVERAGES. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE SHORT TERM PERIOD. TEMPERATURES WERE KEPT 5 DEGREES BELOW SEASONAL AVERAGES SUNDAY...BUT MODERATED CLOSER TO NORMAL BY MONDAY. AN APPROACHING WARM FRONT COULD BRING THE CHANCE FOR A SHOWER IN THE SOUTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY BUT FOR NOW...LEFT LOW END POPS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A WARM FRONT MOVING NORTH ACROSS THE DISTRICT TUESDAY WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. AS THE WARM FRONT MOVES NORTH OF THE FORECAST AREA THURSDAY WARM AND MORE HUMID CONDITIONS WILL RETURN WITH HIGH TEMPERATURES INTO THE 80S THROUGH FRIDAY. THERE WILL BE A SLIGHT CHANCE OF DIURNAL THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... GENERAL STRATO-CU REMAINS IN PLACE EXCEPT AT ZANESVILLE WHERE SKIES HAVE CLEARED. CLOUD DECK IS THIN AND HAS A DIURNAL LOOK ON SAT PIX. BREAKS CONTINUE TO DEVELOP AND WITH DEEP DRYING MOVING INTO REGION OVERNIGHT STILL EXPECT STRATO-CU TO GRADUALLY DISSIPATE TOWARD OR JUST AFTER MIDNIGHT. WINDS ALREADY BEGINNING TO WEAKEN AS SURFACE RIDGE BUILDS EAST FROM GREAT LAKES. 18Z SOUNDINGS SHOW DECOUPLING STILL OCCURRING LATE TONIGHT WITH A NORTH TO NORTHWEST WIND UNDER 6 KTS. BY MID MORNING SATURDAY SUNSHINE WILL MIX DOWN NORTHWEST WINDS WITH GUSTS OVER 20 KTS EXPECTED. ONLY SCT VFR CU EXPECTED. .OUTLOOK.../SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL MAINTAIN GENERAL VFR THROUGH MONDAY. A WARM FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FOR LATE TUESDAY INTO WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR MDZ001. OH...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ020-021- 029-031-073-075. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ001>004- 012-021-022. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
726 PM EDT FRI MAY 24 2013 .SYNOPSIS... DRY AND COOL WEATHER CAN BE EXPECTED FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... ADJUSTMENTS TO WINDS OVERNIGHT...JUST WEAKENED THEM A BIT FASTER. TRIED TO TIME THE DECAYING OF CLOUD DECK...WITH LOW CONFIDENCE. WESTERN EDGE OF CLOUDS ARE ERODING QUICKLY...BUT WITH CYCLONIC FLOW AND COLD AIR ALOFT...TIMING IS DIFFICULT. PREVIOUS DISCUSSION... THE UPPER LEVEL TROUGH WILL CONTINUE TO PIVOT ACROSS THE REGION THROUGH THE AFTERNOON AND EVENING AS HIGH PRESSURE TRIES TO BUILD OVERHEAD AT THE SURFACE. COLD NORTHWEST FLOW CONTINUES TO KEEP CLOUD COVER OVER MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON...WHICH IS RIGHT IN LINE WITH THE LATEST RUC FORECAST. WITH CLOUD COVER STILL IN PLACE...CONTINUED A DOWNWARD TREND IN THE HIGH TEMPERATURES FOR THE AFTERNOON...WITH PIT LIKELY TO BE VERY CLOSE TO BREAKING IT`S LOW HIGH TEMPERATURES RECORD FROM 1877. THE MOST RECENT MODEL RUNS CONTINUE TO SUGGEST THAT CLOUDS WILL EVENTUALLY DIMINISH OVER THE ENTIRE REGION...LASTING LONGEST IN THE RIDGES. HOW FAST THE CLOUDS DIMINISH WILL PLAY A BIG ROLE IN HOW QUICKLY TEMPERATURES DROP OVERNIGHT. HOWEVER...SINCE TEMPERATURES ARE ALREADY LOWER THAN ORIGINALLY FORECAST...CLEARING SKIES SHOULD ALLOW LOWS IN THE LOW TO MID 30`S TO BE REALIZED RELATIVELY QUICKLY. FOR NOW...CONTINUED THE FROST/FREEZE AS IS...ALTHOUGH SOME COUNTIES MAY NEED TO BE UPGRADED TO A FREEZE IF SKIES CLEAR SOONER AND WINDS DECOUPLE. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY BRINGING A CLEAR DAY BUT NORTHWEST FLOW WILL KEEP TEMPERATURES 10 TO 15 BELOW SEASONAL AVERAGES. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE SHORT TERM PERIOD. TEMPERATURES WERE KEPT 5 DEGREES BELOW SEASONAL AVERAGES SUNDAY...BUT MODERATED CLOSER TO NORMAL BY MONDAY. AN APPROACHING WARM FRONT COULD BRING THE CHANCE FOR A SHOWER IN THE SOUTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY BUT FOR NOW...LEFT LOW END POPS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A WARM FRONT MOVING NORTH ACROSS THE DISTRICT TUESDAY WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. AS THE WARM FRONT MOVES NORTH OF THE FORECAST AREA THURSDAY WARM AND MORE HUMID CONDITIONS WILL RETURN WITH HIGH TEMPERATURES INTO THE 80S THROUGH FRIDAY. THERE WILL BE A SLIGHT CHANCE OF DIURNAL THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... GENERAL STRATO-CU REMAINS IN PLACE EXCEPT AT ZANESVILLE WHERE SKIES HAVE CLEARED. CLOUD DECK IS THIN AND HAS A DIURNAL LOOK ON SAT PIX. BREAKS CONTINUE TO DEVELOP AND WITH DEEP DRYING MOVING INTO REGION OVERNIGHT STILL EXPECT STRATO-CU TO GRADUALLY DISSIPATE TOWARD OR JUST AFTER MIDNIGHT. WINDS ALREADY BEGINNING TO WEAKEN AS SURFACE RIDGE BUILDS EAST FROM GREAT LAKES. 18Z SOUNDINGS SHOW DECOUPLING STILL OCCURRING LATE TONIGHT WITH A NORTH TO NORTHWEST WIND UNDER 6 KTS. BY MID MORNING SATURDAY SUNSHINE WILL MIX DOWN NORTHWEST WINDS WITH GUSTS OVER 20 KTS EXPECTED. ONLY SCT VFR CU EXPECTED. .OUTLOOK.../SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL MAINTAIN GENERAL VFR THROUGH MONDAY. A WARM FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FOR LATE TUESDAY INTO WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR MDZ001. OH...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ020-021- 029-031-073-075. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ001>004- 012-021-022. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
523 PM CDT THU MAY 23 2013 .SHORT TERM...THROUGH MONDAY ISSUED AT 204 PM CDT THU MAY 23 2013 23.12Z RAOBS SHOW GOOD 925-850MB COLD ADVECTION ACROSS THE WRN GREAT LAKES THIS MORNING IN MODERATE NORTHEAST FLOW. FRONTAL SLOPE OVER THE STATE IS SOMETHING THAT WILL COME INTO PLAY FOR UPCOMING FORECAST AND HOW FAR IT SLIDES SOUTHWEST. AT 12Z KINL-KABR HAD A 7C TEMPERATURE DIFFERENCE AT 850MB /12C AT 925MB/. A MASSIVE DRYING ACROSS MN OCCURRED OVERNIGHT WITH PRECIPITATELY WATER VALUES PLUMMETING FROM 0.90 TO 0.32 INCHES...OR 136 TO 48 PERCENT NORMAL. THE SURFACE RIDGE NOSING IN IS QUITE DRY WITH PRECIPITABLE WATER VALUES IN THE 30 PERCENT RANGE ACROSS SRN CANADA. THIS GAVE WAY TO A SUNNY BUT COOL DAY TODAY. A HIGHER AMPLITUDE RIDGE AXIS IS ANCHORED IN THE DAKOTAS AND SOUTH...WHILE A DEEPER CYCLONE HAS NOW SHIFTED ONSHORE INTO THE NWRN U.S. NUMEROUS SPOKES OF ENERGY ARE CIRCULATING AROUND THAT LOW...ONE OF WHICH IS QUITE STRONG OVER NEVADA WITH RAP ANALYSIS SHOWING A TROPOPAUSE FOLD TO NEAR 500MB...ON THE POLEWARD SIDE OF A MEASURED 100KT 250MB JET CORE NOSE. THIS IS DRIVING HEIGHT FALLS ACROSS MT/ID/UT. SURFACE DEW POINTS OF MEANING FOR CONVECTION ARE LOCATED IN OKLAHOMA...SOON TO RETURN NORTHWARD. FORECAST IS ON TRACK FOR CALMING WINDS TONIGHT AND CLEAR SKIES. WIDESPREAD FROST SHOULD OCCUR WITH LOWER 30S FORECAST ACROSS NWRN WI. WITH LOWER DEW POINTS OVER NWRN WI COUNTIES CURRENTLY...HAVE DECIDED TO JUST ADD ALL OF THOSE COUNTIES INTO THE FROST ADVISORY. BIG PICTURE DURING THIS PERIOD IS FALLING HEIGHTS AND PRESSURE IN THE FRONT RANGE WITH SOUTHERLY FLOW INCREASING AND A RETURN OF MOISTURE TO NEB/SD FRIDAY NIGHT. THIS WILL PLACE THE LOW-LEVEL THERMAL BOUNDARY ACROSS THE FORECAST AREA FROM 850-925MB...SLIGHTLY DISPLACED SWWRD...FROM KABR-KMLI. THE CONSENSUS NCEP MODELS AT 23.12Z REMAIN CONSISTENT WITH THEIR PREVIOUS RUNS ON THE FRONTAL BOUNDARY BECOMING ACTIVE IN THE DAKOTAS/NEB FRIDAY EVENING AND SHIFTING EAST INTO MN/IA OVERNIGHT. THE 23.00Z ECMWF/UKMET SOLUTIONS DO AS WELL...HOWEVER THEY REMAIN FURTHER WEST. THE 300/305K SURFACE IN THE NCEP SOLUTIONS REMAINS CONSISTENT WITH AN 8G/KG MOISTURE SURGE ISENTROPICALLY LIFTING AND CONVERGING INTO CENTRAL AND ERN MN FRIDAY OVERNIGHT WITH A FETCH OF ABOUT 500 J/KG OF MUCAPE FEEDING IT. THE NAM SEEMS TO BE THE MOST AGRESSIVE. NOT OVERLY IMPRESSIVE FOR SEVERE WEATHER...BUT RATHER THERE IS ENOUGH FORCING TO GENERATE RA/TSRA SWWRD OF MSP. THE ECMWF SOLUTIONS SUGGEST MORE OF A FOCUS IN SRN/SWRN MN. THE MAIN QUESTION IS HOW FAR EAST DOES THIS CONVECTIVE COMPLEX TRACK FRIDAY NIGHT AND HOW FAR EAST DOES THE FRONTAL BOUNDARY LIFT. HAVE INCREASED RAIN CHANCES FURTHER EAST FOR FRIDAY NIGHT AND SATURDAY...HOWEVER WITH THE VERIFICATION RECORD OF THE ECMWF...THERE IS STILL A CHANCE THE EASTERN AREAS WILL BE DRY. CONFIDENCE IS LOW ON THE EXACT LOCATION OF THE WEATHER...BUT HIGHER THAT IT WILL BE AN ACTIVE FRONTAL ZONE WITH SHRA/ISO TSRA. THIS QUESTION REMAINS THROUGH MONDAY...HOW FAR EAST WILL THE FRONTAL BAND BE LOCATED. THE FRONT WILL LIKELY REMAIN ACTIVE WITH SHOWERS/STORMS AND CLOUDS...AND HIGHS QUITE A BIT COOLER THANOUTSIDE THE BAND. OVERALL...HAVE INCREASED RAIN CHANCES IN THE WRN/SRN FORECAST AREA AND TRIED TO REMAIN NEARLY DRY IN THE EAST. SEEMS LIKE IT WILL BE A CLOUDY WEEKEND...AND THUS HAVE LOWERED HIGHS SUNDAY AND MONDAY AS WELL. SEVERE WEATHER THREATS ARE MOST POSSIBLE IN SWRN MN CLOSER TO THE CAPE POOL...AND MONDAY LOOKS MOST FAVORABLE SHOULD THE INSTABILITY INCREASE AS THE WARM FRONT MOVES TOWARD MN. HOWEVER...ACTIVITY ALONG THAT FRONT THIS WEEKEND MAY HAVE MUCH TO DO WITH HOW THE ENVIRONMENT/FRONT EVOLVES MONDAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 241 PM CDT THU MAY 23 2013 IT CONTINUES TO LOOK LIKE WE/LL UNFORTUNATELY NEED TO KEEP A PROLONGED PERIOD OF CHANCE POPS IN THE FORECAST THROUGH THE WEEK AS THE BAROCLINIC ZONE LINGERS IN THE AREA... WITH ELEVATED INSTABILITY AND PERSISTENT WARM ADVECTION WORK TO GENERATE SCATTERED SHRA/TSRA. THERE WILL UNDOUBTEDLY BE SOME DRY PERIODS... WITH PCPN FOCUSED WHEN INDIVIDUAL SHORTWAVES RIPPLE SOUTHEAST THROUGH THE UPPER FLOW... BUT AT THIS POINT IT IS IMPOSSIBLE TO TRY AND PIN POINT WHEN SUCH DRY PERIODS MIGHT OCCUR. THE 12Z ECMWF HAS COME AROUND MORE IN LINE WITH THE GFS IN KEEPING THINGS MORE ACTIVE IN OUR AREA THROUGHOUT THE TIME PERIOD... ALTHOUGH BOTH SUGGEST WE SHOULD FINALLY BRING THE UPPER TROUGH EAST TOWARD THE REGION BY THE END OF THE WEEK. DEPENDING ON HOW THAT UNFOLDS... WE COULD HAVE A POSSIBILITY FOR FOCUSED CONVECTION AND POSSIBLE SEVERE WEATHER DURING THE THURSDAY-FRIDAY TIME FRAME. BUT... UNTIL THAT POINT THE MAIN ISSUES WOULD LIKELY BE LOCALLY HEAVY RAIN AND PERHAPS SOME HAIL. IN GENERAL... TEMPERATURES WILL WARM THROUGH THE WEEK AS THE BONAFIDE WARM SECTOR SLOWLY LIFTS NORTH INTO THE AREA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 459 PM CDT THU MAY 23 2013 VFR DURING THE PERIOD. INCREASING HIGH CLOUDS FROM THE WEST DURING THE DAY FRIDAY. CHANCE OF SHRA LIMITED TO FAR WESTERN SITES. INTRODUCED VCSH FOR NOW. LIGHT NORTHEAST TO EAST WINDS BECOMING SOUTHEAST OVERNIGHT AND INCREASING ON FRIDAY. GUSTY AT MN SITES BY MIDDAY. KMSP... VFR THROUGH PERIOD. NEXT CHANCE OF SHOWERS MOVES IN LATER FRIDAY NIGHT. LIGHT NORTHEAST TO EAST WIND BECOMING SOUTHEAST FRIDAY AND A BIT GUSTY BY MIDDAY. /OUTLOOK FOR KMSP/ FRIDAY NIGHT...VFR. CHANCE OF SHOWERS. SOUTHEAST WIND 5 TO 15 KT. SATURDAY...BRIEF MVFR CEILINGS POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT. SATURDAY NIGHT...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT. SUNDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA...BRIEF IFR CONDITIONS POSSIBLE. SOUTHEAST WIND 10 TO 20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT FRIDAY FOR MNZ045-052-053-063. WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT FRIDAY FOR WIZ014>016-023>028. && $$ SHORT TERM...BAUMGARDT/ARX LONG TERM... AVIATION...DE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
246 PM CDT THU MAY 23 2013 .SHORT TERM...THROUGH MONDAY ISSUED AT 204 PM CDT THU MAY 23 2013 23.12Z RAOBS SHOW GOOD 925-850MB COLD ADVECTION ACROSS THE WRN GREAT LAKES THIS MORNING IN MODERATE NORTHEAST FLOW. FRONTAL SLOPE OVER THE STATE IS SOMETHING THAT WILL COME INTO PLAY FOR UPCOMING FORECAST AND HOW FAR IT SLIDES SOUTHWEST. AT 12Z KINL-KABR HAD A 7C TEMPERATURE DIFFERENCE AT 850MB /12C AT 925MB/. A MASSIVE DRYING ACROSS MN OCCURRED OVERNIGHT WITH PRECIPITATELY WATER VALUES PLUMMETING FROM 0.90 TO 0.32 INCHES...OR 136 TO 48 PERCENT NORMAL. THE SURFACE RIDGE NOSING IN IS QUITE DRY WITH PRECIPITABLE WATER VALUES IN THE 30 PERCENT RANGE ACROSS SRN CANADA. THIS GAVE WAY TO A SUNNY BUT COOL DAY TODAY. A HIGHER AMPLITUDE RIDGE AXIS IS ANCHORED IN THE DAKOTAS AND SOUTH...WHILE A DEEPER CYCLONE HAS NOW SHIFTED ONSHORE INTO THE NWRN U.S. NUMEROUS SPOKES OF ENERGY ARE CIRCULATING AROUND THAT LOW...ONE OF WHICH IS QUITE STRONG OVER NEVADA WITH RAP ANALYSIS SHOWING A TROPOPAUSE FOLD TO NEAR 500MB...ON THE POLEWARD SIDE OF A MEASURED 100KT 250MB JET CORE NOSE. THIS IS DRIVING HEIGHT FALLS ACROSS MT/ID/UT. SURFACE DEW POINTS OF MEANING FOR CONVECTION ARE LOCATED IN OKLAHOMA...SOON TO RETURN NORTHWARD. FORECAST IS ON TRACK FOR CALMING WINDS TONIGHT AND CLEAR SKIES. WIDESPREAD FROST SHOULD OCCUR WITH LOWER 30S FORECAST ACROSS NWRN WI. WITH LOWER DEW POINTS OVER NWRN WI COUNTIES CURRENTLY...HAVE DECIDED TO JUST ADD ALL OF THOSE COUNTIES INTO THE FROST ADVISORY. BIG PICTURE DURING THIS PERIOD IS FALLING HEIGHTS AND PRESSURE IN THE FRONT RANGE WITH SOUTHERLY FLOW INCREASING AND A RETURN OF MOISTURE TO NEB/SD FRIDAY NIGHT. THIS WILL PLACE THE LOW-LEVEL THERMAL BOUNDARY ACROSS THE FORECAST AREA FROM 850-925MB...SLIGHTLY DISPLACED SWWRD...FROM KABR-KMLI. THE CONSENSUS NCEP MODELS AT 23.12Z REMAIN CONSISTENT WITH THEIR PREVIOUS RUNS ON THE FRONTAL BOUNDARY BECOMING ACTIVE IN THE DAKOTAS/NEB FRIDAY EVENING AND SHIFTING EAST INTO MN/IA OVERNIGHT. THE 23.00Z ECMWF/UKMET SOLUTIONS DO AS WELL...HOWEVER THEY REMAIN FURTHER WEST. THE 300/305K SURFACE IN THE NCEP SOLUTIONS REMAINS CONSISTENT WITH AN 8G/KG MOISTURE SURGE ISENTROPICALLY LIFTING AND CONVERGING INTO CENTRAL AND ERN MN FRIDAY OVERNIGHT WITH A FETCH OF ABOUT 500 J/KG OF MUCAPE FEEDING IT. THE NAM SEEMS TO BE THE MOST AGRESSIVE. NOT OVERLY IMPRESSIVE FOR SEVERE WEATHER...BUT RATHER THERE IS ENOUGH FORCING TO GENERATE RA/TSRA SWWRD OF MSP. THE ECMWF SOLUTIONS SUGGEST MORE OF A FOCUS IN SRN/SWRN MN. THE MAIN QUESTION IS HOW FAR EAST DOES THIS CONVECTIVE COMPLEX TRACK FRIDAY NIGHT AND HOW FAR EAST DOES THE FRONTAL BOUNDARY LIFT. HAVE INCREASED RAIN CHANCES FURTHER EAST FOR FRIDAY NIGHT AND SATURDAY...HOWEVER WITH THE VERIFICATION RECORD OF THE ECMWF...THERE IS STILL A CHANCE THE EASTERN AREAS WILL BE DRY. CONFIDENCE IS LOW ON THE EXACT LOCATION OF THE WEATHER...BUT HIGHER THAT IT WILL BE AN ACTIVE FRONTAL ZONE WITH SHRA/ISO TSRA. THIS QUESTION REMAINS THROUGH MONDAY...HOW FAR EAST WILL THE FRONTAL BAND BE LOCATED. THE FRONT WILL LIKELY REMAIN ACTIVE WITH SHOWERS/STORMS AND CLOUDS...AND HIGHS QUITE A BIT COOLER THANOUTSIDE THE BAND. OVERALL...HAVE INCREASED RAIN CHANCES IN THE WRN/SRN FORECAST AREA AND TRIED TO REMAIN NEARLY DRY IN THE EAST. SEEMS LIKE IT WILL BE A CLOUDY WEEKEND...AND THUS HAVE LOWERED HIGHS SUNDAY AND MONDAY AS WELL. SEVERE WEATHER THREATS ARE MOST POSSIBLE IN SWRN MN CLOSER TO THE CAPE POOL...AND MONDAY LOOKS MOST FAVORABLE SHOULD THE INSTABILITY INCREASE AS THE WARM FRONT MOVES TOWARD MN. HOWEVER...ACTIVITY ALONG THAT FRONT THIS WEEKEND MAY HAVE MUCH TO DO WITH HOW THE ENVIRONMENT/FRONT EVOLVES MONDAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 241 PM CDT THU MAY 23 2013 IT CONTINUES TO LOOK LIKE WE/LL UNFORTUNATELY NEED TO KEEP A PROLONGED PERIOD OF CHANCE POPS IN THE FORECAST THROUGH THE WEEK AS THE BAROCLINIC ZONE LINGERS IN THE AREA... WITH ELEVATED INSTABILITY AND PERSISTENT WARM ADVECTION WORK TO GENERATE SCATTERED SHRA/TSRA. THERE WILL UNDOUBTEDLY BE SOME DRY PERIODS... WITH PCPN FOCUSED WHEN INDIVIDUAL SHORTWAVES RIPPLE SOUTHEAST THROUGH THE UPPER FLOW... BUT AT THIS POINT IT IS IMPOSSIBLE TO TRY AND PIN POINT WHEN SUCH DRY PERIODS MIGHT OCCUR. THE 12Z ECMWF HAS COME AROUND MORE IN LINE WITH THE GFS IN KEEPING THINGS MORE ACTIVE IN OUR AREA THROUGHOUT THE TIME PERIOD... ALTHOUGH BOTH SUGGEST WE SHOULD FINALLY BRING THE UPPER TROUGH EAST TOWARD THE REGION BY THE END OF THE WEEK. DEPENDING ON HOW THAT UNFOLDS... WE COULD HAVE A POSSIBILITY FOR FOCUSED CONVECTION AND POSSIBLE SEVERE WEATHER DURING THE THURSDAY-FRIDAY TIME FRAME. BUT... UNTIL THAT POINT THE MAIN ISSUES WOULD LIKELY BE LOCALLY HEAVY RAIN AND PERHAPS SOME HAIL. IN GENERAL... TEMPERATURES WILL WARM THROUGH THE WEEK AS THE BONAFIDE WARM SECTOR SLOWLY LIFTS NORTH INTO THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1243 PM CDT THU MAY 23 2013 HIGH PRESSURE AREA BUILDING IN WITH NEARLY CLEAR SKIES/VFR. LARGEST 3 HOURLY PRESSURE CLIMBS ARE SHIFTING OFF TO THE SOUTHEAST SO GRADIENT WILL SLACKEN CONSIDERABLY GOING INTO THIS EVENING. EXPECT ANY LINGERING GUSTS TO CALM DOWN AND WITH RIDGE AXIS SPREADING THROUGH TONIGHT...GRADUAL SHIFT TO SOUTHEAST LOW LEVEL FLOW WILL MATERIALIZE GOING INTO FRIDAY MORNING. DRY AIRMASS SHOULD KEEP SKIES CLEAR THROUGH MOST OF FRIDAY AS WELL. KMSP... VFR CONDITIONS TO CONTINUE. NORTHEAST WIND THIS AFTERNOON WILL DECREASE AND SLOWLY BECOME SOUTHEAST BY FRIDAY MORNING. /OUTLOOK FOR KMSP/ FRIDAY NIGHT...VFR. CHANCE OF SHOWERS. SOUTHEAST WIND 5 TO 15 KT. SATURDAY...BRIEF MVFR CEILINGS POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT. SATURDAY NIGHT...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT. SUNDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA...BRIEF IFR CONDITIONS POSSIBLE. SOUTHEAST WIND 10 TO 20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT FRIDAY FOR MNZ045-052-053-063. WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT FRIDAY FOR WIZ014>016-023>028. && $$ SHORT TERM...BAUMGARDT/ARX LONG TERM... AVIATION....SHEA/ARX
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
ISSUED BY NATIONAL WEATHER SERVICE LA CROSSE WI 206 PM CDT THU MAY 23 2013 .SHORT TERM...THROUGH MONDAY ISSUED AT 204 PM CDT THU MAY 23 2013 23.12Z RAOBS SHOW GOOD 925-850MB COLD ADVECTION ACROSS THE WRN GREAT LAKES THIS MORNING IN MODERATE NORTHEAST FLOW. FRONTAL SLOPE OVER THE STATE IS SOMETHING THAT WILL COME INTO PLAY FOR UPCOMING FORECAST AND HOW FAR IT SLIDES SOUTHWEST. AT 12Z KINL-KABR HAD A 7C TEMPERATURE DIFFERENCE AT 850MB /12C AT 925MB/. A MASSIVE DRYING ACROSS MN OCCURRED OVERNIGHT WITH PRECIPITATELY WATER VALUES PLUMMETING FROM 0.90 TO 0.32 INCHES...OR 136 TO 48 PERCENT NORMAL. THE SURFACE RIDGE NOSING IN IS QUITE DRY WITH PRECIPITABLE WATER VALUES IN THE 30 PERCENT RANGE ACROSS SRN CANADA. THIS GAVE WAY TO A SUNNY BUT COOL DAY TODAY. A HIGHER AMPLITUDE RIDGE AXIS IS ANCHORED IN THE DAKOTAS AND SOUTH...WHILE A DEEPER CYCLONE HAS NOW SHIFTED ONSHORE INTO THE NWRN U.S. NUMEROUS SPOKES OF ENERGY ARE CIRCULATING AROUND THAT LOW...ONE OF WHICH IS QUITE STRONG OVER NEVADA WITH RAP ANALYSIS SHOWING A TROPOPAUSE FOLD TO NEAR 500MB...ON THE POLEWARD SIDE OF A MEASURED 100KT 250MB JET CORE NOSE. THIS IS DRIVING HEIGHT FALLS ACROSS MT/ID/UT. SURFACE DEW POINTS OF MEANING FOR CONVECTION ARE LOCATED IN OKLAHOMA...SOON TO RETURN NORTHWARD. FORECAST IS ON TRACK FOR CALMING WINDS TONIGHT AND CLEAR SKIES. WIDESPREAD FROST SHOULD OCCUR WITH LOWER 30S FORECAST ACROSS NWRN WI. WITH LOWER DEW POINTS OVER NWRN WI COUNTIES CURRENTLY...HAVE DECIDED TO JUST ADD ALL OF THOSE COUNTIES INTO THE FROST ADVISORY. BIG PICTURE DURING THIS PERIOD IS FALLING HEIGHTS AND PRESSURE IN THE FRONT RANGE WITH SOUTHERLY FLOW INCREASING AND A RETURN OF MOISTURE TO NEB/SD FRIDAY NIGHT. THIS WILL PLACE THE LOW-LEVEL THERMAL BOUNDARY ACROSS THE FORECAST AREA FROM 850-925MB...SLIGHTLY DISPLACED SWWRD...FROM KABR-KMLI. THE CONSENSUS NCEP MODELS AT 23.12Z REMAIN CONSISTENT WITH THEIR PREVIOUS RUNS ON THE FRONTAL BOUNDARY BECOMING ACTIVE IN THE DAKOTAS/NEB FRIDAY EVENING AND SHIFTING EAST INTO MN/IA OVERNIGHT. THE 23.00Z ECMWF/UKMET SOLUTIONS DO AS WELL...HOWEVER THEY REMAIN FURTHER WEST. THE 300/305K SURFACE IN THE NCEP SOLUTIONS REMAINS CONSISTENT WITH AN 8G/KG MOISTURE SURGE ISENTROPICALLY LIFTING AND CONVERGING INTO CENTRAL AND ERN MN FRIDAY OVERNIGHT WITH A FETCH OF ABOUT 500 J/KG OF MUCAPE FEEDING IT. THE NAM SEEMS TO BE THE MOST AGRESSIVE. NOT OVERLY IMPRESSIVE FOR SEVERE WEATHER...BUT RATHER THERE IS ENOUGH FORCING TO GENERATE RA/TSRA SWWRD OF MSP. THE ECMWF SOLUTIONS SUGGEST MORE OF A FOCUS IN SRN/SWRN MN. THE MAIN QUESTION IS HOW FAR EAST DOES THIS CONVECTIVE COMPLEX TRACK FRIDAY NIGHT AND HOW FAR EAST DOES THE FRONTAL BOUNDARY LIFT. HAVE INCREASED RAIN CHANCES FURTHER EAST FOR FRIDAY NIGHT AND SATURDAY...HOWEVER WITH THE VERIFICATION RECORD OF THE ECMWF...THERE IS STILL A CHANCE THE EASTERN AREAS WILL BE DRY. CONFIDENCE IS LOW ON THE EXACT LOCATION OF THE WEATHER...BUT HIGHER THAT IT WILL BE AN ACTIVE FRONTAL ZONE WITH SHRA/ISO TSRA. THIS QUESTION REMAINS THROUGH MONDAY...HOW FAR EAST WILL THE FRONTAL BAND BE LOCATED. THE FRONT WILL LIKELY REMAIN ACTIVE WITH SHOWERS/STORMS AND CLOUDS...AND HIGHS QUITE A BIT COOLER THANOUTSIDE THE BAND. OVERALL...HAVE INCREASED RAIN CHANCES IN THE WRN/SRN FORECAST AREA AND TRIED TO REMAIN NEARLY DRY IN THE EAST. SEEMS LIKE IT WILL BE A CLOUDY WEEKEND...AND THUS HAVE LOWERED HIGHS SUNDAY AND MONDAY AS WELL. SEVERE WEATHER THREATS ARE MOST POSSIBLE IN SWRN MN CLOSER TO THE CAPE POOL...AND MONDAY LOOKS MOST FAVORABLE SHOULD THE INSTABILITY INCREASE AS THE WARM FRONT MOVES TOWARD MN. HOWEVER...ACTIVITY ALONG THAT FRONT THIS WEEKEND MAY HAVE MUCH TO DO WITH HOW THE ENVIRONMENT/FRONT EVOLVES MONDAY. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 415 AM CDT THU MAY 23 2013 THE LONG TERM BEGINS WITH A LARGE HIGH PRESSURE SYSTEM OVER THE WESTERN GREAT LAKES REGION. MUCH OF FRIDAY WILL BE DRY...WITH THE EXCEPTION OF THE FAR WEST WHERE STRONG LOW LEVEL THETA-E ADVECTION WILL COMMENCE IN THE AFTERNOON ON THE BACK SIDE OF THE HIGH. THIS COUPLED WITH A SHORT WAVE AND MID LEVEL FRONTOGENESIS MOVING EAST FROM THE NORTHERN PLAINS WILL DRIVE SHOWERS AND ISOLATED THUNDERSTORMS INTO THE FAR WEST BY LATE AFTERNOON...WITH THE ACTIVITY PASSING ACROSS THE FA FRIDAY NIGHT AND EARLY SATURDAY. ELEVATED INSTABILITY IS MINIMAL FRIDAY NIGHT AND SEVERE WEATHER IS NOT EXPECTED. THE BEST LOW LEVEL MOISTURE TRANSPORT IS AIMED FROM THE CENTRAL PLAINS INTO IA FRIDAY NIGHT WITH JUST ABOUT ALL MODEL SOLUTIONS POINTING TO THE HIGHEST QPF STAYING SOUTH OF MN. IN THE WAKE OF THE SHORT WAVE ON SATURDAY...WE ARE BEGINNING TO SEE THE NAM AND SREF TAKING ON MORE OF WHAT THE ECMWF HAS BEEN SHOWING FOR 3 DAYS NOW...AND THAT IS A MORE AMPLIFIED FLOW ALOFT. THIS IS VERY EVIDENT LOOKING AT THREE RUNS OF THE ECMWF SPACED 24 HOURS APART. DEEPER UPPER LOWS ALONG BOTH COAST WITH MORE RIDGING IN THE CENTER OF THE COUNTRY. WITH TIME...THIS BUILDS THE SURFACE HIGH PRESSURE SYSTEM OVER THE GREAT LAKES BACK WEST ACROSS THE FA ALONG WITH DRIER AIR. USING THE ECMWF OUTRIGHT WOULD PLACE DRY WEATHER OVER ALL BUT OUR FAR WESTERN AND SOUTHERN COUNTIES IN MN FOR SUNDAY AND MONDAY. GOING AGAINST THE GRAIN HOWEVER ARE THE GFS AND GEM. BOTH ARE ADAMANT ON DRIVING WAVE AFTER WAVE ALOFT THROUGH THE REGION BOTH DAYS WITH CONVECTIVE CLUSTERS. MODEL RUN QPF IS IN THE SEVERAL INCH RANGE ACROSS PARTS OF THE MN CWA. ON THE OTHER HAND... THE ECMWF ONLY HAS A TENTH TO A HALF INCH FROM NORTHEAST TO SOUTHWEST ACROSS OUR AREA RESPECTIVELY FROM FRIDAY THROUGH MONDAY. HENCE...THE WEEKEND/HOLIDAY MAY TURN OUT BETTER THAN THE FORECAST INDICATES IF THE ECMWF IS MORE CORRECT. POPS ARE MORE ALIGNED NOW WITH VERY LOW CHANCES IN WI WITH HIGHER CHANCES NEAR THE WESTERN AND SOUTHERN BORDER. ALTHOUGH THE RAIN CHANCES ARE DIMINISHING AFTER SATURDAY MORNING...THERE IS GOOD CONSENSUS THAT ABUNDANT LOW LEVEL MOISTURE WILL COVER THE AREA WITH A WARM FRONT REMAINING SOUTH OF US. THIS WILL LIKELY YIELD PLENTY OF CLOUD COVER WITH HIGH TEMPERATURES REMAINING IN THE 60S SATURDAY AND SUNDAY WITH UPPER 60S TO LOWER 70S ON SUNDAY. SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE COMMON OVER THE REGION FROM TUESDAY ONWARD AS THE TROUGH IN THE WEST MOVES EAST. THIS WILL LIFT THE LOW PRESSURE SYSTEM AND WARM FRONT INTO OUT AREA. THIS WILL ALSO INCREASE OUR THREAT FOR SEVERE WEATHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1243 PM CDT THU MAY 23 2013 HIGH PRESSURE AREA BUILDING IN WITH NEARLY CLEAR SKIES/VFR. LARGEST 3 HOURLY PRESSURE CLIMBS ARE SHIFTING OFF TO THE SOUTHEAST SO GRADIENT WILL SLACKEN CONSIDERABLY GOING INTO THIS EVENING. EXPECT ANY LINGERING GUSTS TO CALM DOWN AND WITH RIDGE AXIS SPREADING THROUGH TONIGHT...GRADUAL SHIFT TO SOUTHEAST LOW LEVEL FLOW WILL MATERIALIZE GOING INTO FRIDAY MORNING. DRY AIRMASS SHOULD KEEP SKIES CLEAR THROUGH MOST OF FRIDAY AS WELL. KMSP... VFR CONDITIONS TO CONTINUE. NORTHEAST WIND THIS AFTERNOON WILL DECREASE AND SLOWLY BECOME SOUTHEAST BY FRIDAY MORNING. /OUTLOOK FOR KMSP/ FRIDAY NIGHT...VFR. CHANCE OF SHOWERS. SOUTHEAST WIND 5 TO 15 KT. SATURDAY...BRIEF MVFR CEILINGS POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT. SATURDAY NIGHT...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT. SUNDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA...BRIEF IFR CONDITIONS POSSIBLE. SOUTHEAST WIND 10 TO 20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT FRIDAY FOR WIZ014>016-023>028. && $$ SHORT TERM...BAUMGARDT/ARX LONG TERM...RAH AVIATION....SHEA/ARX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
635 PM CDT FRI MAY 24 2013 .AVIATION... 00Z TAFS FOR KOMA...KLNK AND KOFK. WILL WATCH PCPN CURRENTLY WEST OF KLNK...BUT DID NOT INCLUDE THIS IN CURRENT TAF. WILL AMEND IF NEEDED. OTHERWISE...FAIRLY LOW CONFIDENCE FORECAST ON TIMING OF TSRA. OVERALL...EXPECT CONDITIONS TO DETERIORATE OVERNIGHT AS LOW LEVEL MOISTURE INCREASES. ALL THREE SITES SHOULD DROP TO MVFR AND POSSIBLY TO IFR. LOOKING AT THE LATEST 13KM RAP MODEL...EXPECT ACTIVITY CURRENTLY IN SOUTHWEST NEBRASKA TO TRACK AND DEVELOP NORTHEAST TOWARD KOFK BY 08Z OR 09Z. CHANCES SEEM LOWER AT KLNK AND KOMA UNTIL LATE TONIGHT. THERE WILL BE SOME CHANCE OF TSRA AT ALL THREE SITES 18Z-00Z TOMORROW BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN TAFS AT THIS TIME. MILLER && .PREV DISCUSSION... /ISSUED 252 PM CDT FRI MAY 24 2013/ DISCUSSION... TIMING OF BEST PRECIPITATION CHANCES THROUGH MEMORIAL DAY WEEKEND AND BEYOND MAIN CHALLENGE AND CONFIDENCE OF SKILL BEYOND CLIMATOLOGY...I.E. HIGHEST POPS AT NIGHT...NOT THE HIGHEST. 18Z SURFACE + 12Z UPPER AIR ANALYSIS HAD SURFACE TO 850 MOIST AXIS AND SUBJECTIVELY PLACED WARM FRONT FM SCNTRL KS INTO SWRN NEBR. ALTHOUGH A FEW HIGH BASED SHOWERS DEVELOPING NE OF BOUNDARY IN SCNTRL NEBR AND OTHER POSSIBLE HIGHER BASED ACTIVITY ACROSS NRN/NERN ZONES EARLY WILL HAVE TO BE MONITORED...MAIN ACTION OVER THE FORECAST AREA WILL PROBABLY BE FROM LATE THIS EVENING THROUGH OVERNIGHT HOURS. ANY CONVECTION THAT INCREASES THROUGH THIS EVENING WRN HIGH PLAINS WILL BE AIDED BY DECENT THETA ADVECTION INTO BOUNDARY AS LOW LEVEL JET STRENGTHENS. 12Z GFS WAS PROBABLY SUFFERING FEEDBACK ISSUES BY 12Z SAT IN SRN PLACEMENT OF MCS. HOWEVER...SOME SRN EXTENSION OF AN MCS COULD MAKE IT INTO FAR SWRN ZONES EARLY TONIGHT THUS LIKELY POPS ALL OF WRN ZONES JUST AFT 06Z WITH ANY ACTIVITY THEN FOCUSING MORE ACROSS NERN ZONES SAT MORNING BEFORE EXPECTED DECLINE. AFTER TONIGHT DEEPER MOISTURE WILL OVERSPREAD MUCH OF THE FORECAST AREA WITH MUCH HIGHER THAN NORMAL PRECIPITABLE WATER VALUES GENERALLY LOCKED IN TILL MUCH OF THE ENERGY FROM WRN U.S. TROUGH EJECTS LATE NEXT WEEK. WITH MOISTURE/INSTABILITY IN PLACE AND SOME SORT OF WARM FRONT OR CONVECTIVELY ENHANCED BOUNDARY POSSIBLY REMAINING OVER OR NEAR AREA...STRENGTHENING NOCTURNAL LOW LEVEL JET PLUS ANY DISTURBANCES LIFTING OUT OF WRN TROUGH COULD KEEP ACTIVE PATTERN IN PLACE...ESPECIALLY THROUGH HOLIDAY WEEKEND AND THEN AGAIN BY NEXT THURSDAY. ALTHOUGH DID TRY TO DIURNALLY DECREASE CHCS FROM SW TO NE ACROSS AREA ON SATURDAY...AFTER THAT MADE LITTLE CHANGES TO POPS THROUGH MONDAY...WITH LIKELY POPS GENERALLY RESERVED FOR NIGHTTIME WITH DECREASED DAYTIME POPS IN TUE/WED PERIOD. OVERNIGHT/EARLY SATURDAY CONVECTION COULD REINFORCE BOUNDARY ACROSS FORECAST AREA SATURDAY...THUS KEPT TEMPS CLOSER TO A 00Z ECMWF/12Z NAM COMPROMISE NRN AREAS WITH ANY 80+ MENTION CONFINED TO SOUTHERN ZONES. AFTER MOISTURE BECOMES MORE UNIFORM OVER THE AREA BEYOND SATURDAY...BETTER SFC THERMAL GRADIENT MAY SHIFT NE OF AREA THUS PROVIDING MORE UNIFORM TEMPS ALTHOUGH 00Z ECMWF KEPT SOME BOUNDARY/SLIGHTLY COOLER TEMPS OVER AREA THROUGH MONDAY. CHERMOK && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 PM EDT THU MAY 23 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 240 PM THURSDAY... UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD THIS AFTERNOON AIDED BY A 50-75 KNOT UPPER JET OVER THE UPPER MISSISSIPPI VALLEY. THE SURFACE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL TENNESSEE AND WILL TAKE ITS TIME MOVING ACROSS THE MOUNTAINS THIS EVENING. THE MAIN 500 MB VORT MAX ASSOCIATED WITH THE FRONT WILL NOT ARRIVE UNTIL CLOSER TO 00Z. FRONTAL PASSAGE WILL FINALLY OCCUR AFTER 00Z IN THE NORTHWEST PIEDMONT...CLOSER TO 3Z IN THE TRIANGLE AREA...AND NEAR 6Z FOR THE I-95 CORRIDOR. CURRENT RADAR TRENDS SHOW A MYRIAD OF SURFACE BOUNDARIES LEFT OVER FROM LAST NIGHTS CONVECTION AND DIFFERENTIAL HEATING THIS MORNING. IN ADDITION A SMALL SHORTWAVE TROUGH IS MOVING NORTHWARD FROM UPSTATE SOUTH CAROLINA. AT THIS TIME THE BOUNDARY INITIATING THE MOST CONVECTION SPANS SW TO NE FROM THE ROCKINGHAM AREA TO ROANOKE RAPIDS. AT THIS TIME INGREDIENTS FOR THUNDERSTORMS ARE A BIT HEALTHIER THAN IN PREVIOUS DAYS. CURRENTLY THERE IS ABOUT 1000 ML CAPE IN THE EAST WITH LOW LEVEL LAPSE RATES BETWEEN 7-8. EFFECTIVE SHEAR IS AROUND 20 KNOTS. RAP SOUNDINGS SHOW VERY TALL SKINNY CAPE IN THE HAIL GROWTH ZONE MAKING SEVERE HAIL UNLIKELY IN THIS SCENARIO BUT PEA HAIL IS CERTAINLY POSSIBLE. STRAIGHT HODOGRAPHS WITH 20 KNOTS OF SHEAR SUPPORT A MORE LINEAR MULTICELLULAR CONVECTIVE MODE. THERE IS A RELATIVELY DRIER LAYER NEAR 800 MB WITH A VERY MODEST INVERTED V MAKING SEVERE WINDS A LITTLE BIT MORE POSSIBLE THAN IN PREVIOUS DAYS BUT GUSTS WILL MORE LIKELY TOP OUT IN THE 30-40 KNOT RANGE. CURRENT SPC ANALYSIS ALSO SHOWS AN AREA OF 500-700 J/KG OF DCAPE ACROSS THE SOUTH CENTRAL PORTION OF THE CWA. DESPITE PARAMETERS BEING RELATIVELY BETTER TODAY...MID LEVEL LAPSE RATES ARE STILL VERY WEAK. OVERALL BULK SHEAR IS LOW. THERE IS ENOUGH LIFT IN THE MID LEVELS TO SUPPORT MORE LIGHTNING THAN IN PREVIOUS DAYS BUT ANY SEVERE THREAT WILL BE FAIRLY SUBDUED. AS THE VORT MAX APPROACHES FROM THE NORTHWEST...DYNAMICS WILL IMPROVE SLIGHTLY AND IF THERE IS STILL CONVECTION AROUND THE NORTHWEST PIEDMONT WOULD BE THE MOST LIKELY LOCATION TO SEE SEVERE WEATHER. WITH SEVERE POTENTIAL LOW...HEAVY RAIN AND FLOODING WILL AGAIN BE THE LARGEST THREAT. WHILE ONLY A QUARTER TO A HALF OF AN INCH OF WIDESPREAD PRECIPITATION IS EXPECTED...AREAS RECEIVING HEAVY RAINS OVER THE PAST FEW DAYS WOULD BE A BIT MORE PRIMED FOR URBAN AND SMALL STREAM FLOODING. CORFIDI VECTORS SHOW THAT STORMS SHOULD BE PROGRESSIVE ENOUGH TO AVOID TRAINING BUT ORIENTATION OF INDIVIDUAL BOUNDARIES COULD ALLOW FOR SOME TRAINING CELLS THIS AFTERNOON. MOISTURE TRANSPORT...PW VALUES AND SURFACE CONVERGENCE ARE ALL BEST IN THE COASTAL PLAIN THIS AFTERNOON...MAKING THIS THE MOST LIKELY LOCATION FOR FLOODING TODAY. SOUTH SOUTHWESTERLY WINDS TODAY WILL SHIFT TO NORTHWESTERLY AFTER FRONTAL PASSAGE AND SUSTAINED WINDS WILL ELEVATE TO 10-15 KNOTS. HIGHS TODAY WILL BE LARGELY DEPENDENT UPON CONVECTION AND CLOUD COVER BUT IN GENERAL...UPPER 70S TO NEAR 80 IN THE NW AND LOWER TO MID 80S IN THE SOUTH. LOWS WILL BE DEPENDENT UPON THE TIMING OF THE FRONTAL PASSAGE UPPER 50S TO NEAR 60 IN THE NW AND MID 60S SE. SOME MVFR CEILINGS OR VISIBILITIES COULD BE POSSIBLE IN THE EAST BEFORE MAIN FRONT MOVES THROUGH EARLY FRIDAY MORNING. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... AS OF 240 PM THURSDAY... FRIDAY AND FRIDAY NIGHT... THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT 850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES. -ELLIS SATURDAY THROUGH SUNDAY NIGHT... A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY SUN...FAVOR TEMPS IN THE LOW-MID 70S. TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS. FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY END UP BEING 2-3 DEGREES COOLER THAN FORECAST. MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE 1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S ELSEWHERE. -WSS && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY... 12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER 80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 140 PM THURSDAY... 24 HOUR TAF PERIOD: COMPLICATED LOW CONFIDENCE FORECAST FOR THIS AFTERNOON. SEVERAL OUTFLOW AND DIFFERENTIAL HEATING BOUNDARIES HAVE SET UP ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON. APPROACHING FROM THE SOUTHWEST IS A SHORTWAVE TROUGH THAT WAS LOCATED OVER NORTHERN GA THIS MORNING. ALL OF THESE SURFACE BOUNDARIES WILL BE FOCI FOR THE GENESIS OF SHOWERS AND STORMS THIS AFTERNOON. THE MOST PROMINENT BOUNDARY AT THIS TIME IS BISECTING THE CWA FROM SW TO NE AND WILL BE AFFECTING KFAY AND KRWI IN THE NEXT COUPLE OF HOURS. HEAVY RAIN AND GUSTY WINDS ARE LIKELY WITH THESE STORMS ALONG WITH IFR/MVFR CEILINGS AND VISIBILITIES. OTHERWISE VFR CONDITIONS WILL PREVAIL OUTSIDE OF STORMS WITH WINDS OUT OF THE SOUTH SOUTHWEST AT 5-10 KNOTS. LATER THIS AFTERNOON A MORE CONCENTRATED LINE OF SHOWERS AND STORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL MAKE THEIR WAY ACROSS THE AREA WITH THE TRIAD TERMINALS AFFECTED JUST BEFORE 0Z. THIS LINE WILL SLOWLY PROGRESS EASTWARD GETTING TO KRDU AND KFAY IN THE VICINITY OF 3Z AND KRWI CLOSER TO 6Z. FOR FRIDAY CONDITIONS WILL RETURN TO VFR BUT STRONG GUSTY WINDS WILL BE THE PROBLEM OF THE DAY WITH 15-20 KNOTS SUSTAINED OUT OF THE NORTHWEST GUSTING TO 25-30 KNOTS. SKIES WILL GRADUALLY CLEAR THROUGHOUT THE DAY. LONG TERM: SATURDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS THROUGH MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION THROUGH THE EXTENDED MEMORIAL DAY WEEKEND. && .CLIMATE... MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE NEAR RECORD MIN TEMPS FOR THE DATE. RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH RDU 43 / 1967 43 / 1979 GSO 43 / 1956 42 / 1930 .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ELLIS NEAR TERM...ELLIS SHORT TERM...ELLIS/WSS LONG TERM...WSS AVIATION...ELLIS CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
242 PM EDT THU MAY 23 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 240 PM THURSDAY... UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD THIS AFTERNOON AIDED BY A 50-75 KNOT UPPER JET OVER THE UPPER MISSISSIPPI VALLEY. THE SURFACE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL TENNESSEE AND WILL TAKE ITS TIME MOVING ACROSS THE MOUNTAINS THIS EVENING. THE MAIN 500 MB VORT MAX ASSOCIATED WITH THE FRONT WILL NOT ARRIVE UNTIL CLOSER TO 00Z. FRONTAL PASSAGE WILL FINALLY OCCUR AFTER 00Z IN THE NORTHWEST PIEDMONT...CLOSER TO 3Z IN THE TRIANGLE AREA...AND NEAR 6Z FOR THE I-95 CORRIDOR. CURRENT RADAR TRENDS SHOW A MYRIAD OF SURFACE BOUNDARIES LEFT OVER FROM LAST NIGHTS CONVECTION AND DIFFERENTIAL HEATING THIS MORNING. IN ADDITION A SMALL SHORTWAVE TROUGH IS MOVING NORTHWARD FROM UPSTATE SOUTH CAROLINA. AT THIS TIME THE BOUNDARY INITIATING THE MOST CONVECTION SPANS SW TO NE FROM THE ROCKINGHAM AREA TO ROANOKE RAPIDS. AT THIS TIME INGREDIENTS FOR THUNDERSTORMS ARE A BIT HEALTHIER THAN IN PREVIOUS DAYS. CURRENTLY THERE IS ABOUT 1000 ML CAPE IN THE EAST WITH LOW LEVEL LAPSE RATES BETWEEN 7-8. EFFECTIVE SHEAR IS AROUND 20 KNOTS. RAP SOUNDINGS SHOW VERY TALL SKINNY CAPE IN THE HAIL GROWTH ZONE MAKING SEVERE HAIL UNLIKELY IN THIS SCENARIO BUT PEA HAIL IS CERTAINLY POSSIBLE. STRAIGHT HODOGRAPHS WITH 20 KNOTS OF SHEAR SUPPORT A MORE LINEAR MULTICELLULAR CONVECTIVE MODE. THERE IS A RELATIVELY DRIER LAYER NEAR 800 MB WITH A VERY MODEST INVERTED V MAKING SEVERE WINDS A LITTLE BIT MORE POSSIBLE THAN IN PREVIOUS DAYS BUT GUSTS WILL MORE LIKELY TOP OUT IN THE 30-40 KNOT RANGE. CURRENT SPC ANALYSIS ALSO SHOWS AN AREA OF 500-700 J/KG OF DCAPE ACROSS THE SOUTH CENTRAL PORTION OF THE CWA. DESPITE PARAMETERS BEING RELATIVELY BETTER TODAY...MID LEVEL LAPSE RATES ARE STILL VERY WEAK. OVERALL BULK SHEAR IS LOW. THERE IS ENOUGH LIFT IN THE MID LEVELS TO SUPPORT MORE LIGHTNING THAN IN PREVIOUS DAYS BUT ANY SEVERE THREAT WILL BE FAIRLY SUBDUED. AS THE VORT MAX APPROACHES FROM THE NORTHWEST...DYNAMICS WILL IMPROVE SLIGHTLY AND IF THERE IS STILL CONVECTION AROUND THE NORTHWEST PIEDMONT WOULD BE THE MOST LIKELY LOCATION TO SEE SEVERE WEATHER. WITH SEVERE POTENTIAL LOW...HEAVY RAIN AND FLOODING WILL AGAIN BE THE LARGEST THREAT. WHILE ONLY A QUARTER TO A HALF OF AN INCH OF WIDESPREAD PRECIPITATION IS EXPECTED...AREAS RECEIVING HEAVY RAINS OVER THE PAST FEW DAYS WOULD BE A BIT MORE PRIMED FOR URBAN AND SMALL STREAM FLOODING. CORFIDI VECTORS SHOW THAT STORMS SHOULD BE PROGRESSIVE ENOUGH TO AVOID TRAINING BUT ORIENTATION OF INDIVIDUAL BOUNDARIES COULD ALLOW FOR SOME TRAINING CELLS THIS AFTERNOON. MOISTURE TRANSPORT...PW VALUES AND SURFACE CONVERGENCE ARE ALL BEST IN THE COASTAL PLAIN THIS AFTERNOON...MAKING THIS THE MOST LIKELY LOCATION FOR FLOODING TODAY. SOUTH SOUTHWESTERLY WINDS TODAY WILL SHIFT TO NORTHWESTERLY AFTER FRONTAL PASSAGE AND SUSTAINED WINDS WILL ELEVATE TO 10-15 KNOTS. HIGHS TODAY WILL BE LARGELY DEPENDENT UPON CONVECTION AND CLOUD COVER BUT IN GENERAL...UPPER 70S TO NEAR 80 IN THE NW AND LOWER TO MID 80S IN THE SOUTH. LOWS WILL BE DEPENDENT UPON THE TIMING OF THE FRONTAL PASSAGE UPPER 50S TO NEAR 60 IN THE NW AND MID 60S SE. SOME MVFR CEILINGS OR VISIBILITIES COULD BE POSSIBLE IN THE EAST BEFORE MAIN FRONT MOVES THROUGH EARLY FRIDAY MORNING. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... AS OF 240 PM THURSDAY... FRIDAY AND FRIDAY NIGHT... THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT 850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES. -ELLIS SATURDAY THROUGH SUNDAY NIGHT... A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY SUN...FAVOR TEMPS IN THE LOW-MID 70S. TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS. FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY END UP BEING 2-3 DEGREES COOLER THAN FORECAST. MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE 1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S ELSEWHERE. -WSS && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 255 AM THURSDAY... SATURDAY AND SUNDAY... A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE. UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE. MONDAY THROUGH WEDNESDAY.... THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK... FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE LOWER 60S WEDNESDAY MORNING. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 140 PM THURSDAY... 24 HOUR TAF PERIOD: COMPLICATED LOW CONFIDENCE FORECAST FOR THIS AFTERNOON. SEVERAL OUTFLOW AND DIFFERENTIAL HEATING BOUNDARIES HAVE SET UP ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON. APPROACHING FROM THE SOUTHWEST IS A SHORTWAVE TROUGH THAT WAS LOCATED OVER NORTHERN GA THIS MORNING. ALL OF THESE SURFACE BOUNDARIES WILL BE FOCI FOR THE GENESIS OF SHOWERS AND STORMS THIS AFTERNOON. THE MOST PROMINENT BOUNDARY AT THIS TIME IS BISECTING THE CWA FROM SW TO NE AND WILL BE AFFECTING KFAY AND KRWI IN THE NEXT COUPLE OF HOURS. HEAVY RAIN AND GUSTY WINDS ARE LIKELY WITH THESE STORMS ALONG WITH IFR/MVFR CEILINGS AND VISIBILITIES. OTHERWISE VFR CONDITIONS WILL PREVAIL OUTSIDE OF STORMS WITH WINDS OUT OF THE SOUTH SOUTHWEST AT 5-10 KNOTS. LATER THIS AFTERNOON A MORE CONCENTRATED LINE OF SHOWERS AND STORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL MAKE THEIR WAY ACROSS THE AREA WITH THE TRIAD TERMINALS AFFECTED JUST BEFORE 0Z. THIS LINE WILL SLOWLY PROGRESS EASTWARD GETTING TO KRDU AND KFAY IN THE VICINITY OF 3Z AND KRWI CLOSER TO 6Z. FOR FRIDAY CONDITIONS WILL RETURN TO VFR BUT STRONG GUSTY WINDS WILL BE THE PROBLEM OF THE DAY WITH 15-20 KNOTS SUSTAINED OUT OF THE NORTHWEST GUSTING TO 25-30 KNOTS. SKIES WILL GRADUALLY CLEAR THROUGHOUT THE DAY. LONG TERM: SATURDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS THROUGH MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION THROUGH THE EXTENDED MEMORIAL DAY WEEKEND. && .CLIMATE... MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE NEAR RECORD MIN TEMPS FOR THE DATE. RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH RDU 43 / 1967 43 / 1979 GSO 43 / 1956 42 / 1930 .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ELLIS NEAR TERM...ELLIS SHORT TERM...ELLIS/WSS LONG TERM...MLM AVIATION...ELLIS CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EDT THU MAY 23 2013 .SYNOPSIS... A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH WILL SETTLE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS OUR REGION THROUGH THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1010 PM WEDNESDAY... ANY SHOWERS AND THUNDERSTORMS FROM THIS AFTERNOON AND EVENING ASSOCIATED WITH THE SEA BREEZE AND OUTFLOW ACROSS THE EASTERN TWO-THIRDS OF THE AREA HAVE DISSIPATED WITH THE LOSS OF DAYTIME HEATING AND RESULTANT STABILIZING BOUNDARY LAYER. CONVECTION THAT FIRED ACROSS THE HIGHER TERRAIN TODAY... HAS GENERALLY STAYED TO THE WEST OF THE REGION WITH A 15 TO 20 KT SOUTH-SOUTHWESTERLY MEAN STEERING FLOW. HOWEVER... A WEST-NORTHWESTERLY OUTFLOW... GENERATED FROM THESE CLUSTERS OF SHOWERS AND STORMS THAT ORIGINATED ALONG THE HIGHER TERRAIN... HAS FINALLY ALLOWED FOR THE DEVELOPMENT OF SHOWERS AND STORMS ACROSS OUR FAR NORTHWESTERN REACHES OF OUR CWA... ALONG THE OUTFLOW. THINK THIS OUTFLOW SHOULD SUPPORT AT LEAST SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS OUR WESTERN PIEDMONT THROUGH 06/07Z... GIVEN 500 TO 1000 J/KG OF SURFACE BASED CAPE. THEREAFTER... EXPECT BOUNDARY LAYER COOLING SHOULD YIELD A TREND TO ISOLATED SHOWERS AT BEST. ANY SIGNIFICANT S/W ENERGY ROTATING THROUGH THE CYCLONIC FLOW ALOFT FROM THE APPROACHING MID LEVEL TROUGH WELL TO THE WEST OF THE AREA... INVOF THE MS RIVER THIS EVENING... IS EXPECTED TO PASS TO THE WEST AND NORTH OF THE REGION THUS... PLAN TO TRIM POPS TO SLIGHT CHANCE BY EARLY THURSDAY MORNING ACROSS THE ENTIRE CWA. THIS IS SUPPORTED BY THE LATEST HRRR. HOWEVER... ITS WORTH NOTING THE LATEST HRRR DOES SHOW SOME SHOWERS CURRENTLY OFF THE CAROLINA COAST MOVING ONSHORE OVERNIGHT ACROSS THE COASTAL PLAIN. CURRENT HI-RES MODELS GENERALLY SHOW THIS PRECIP REMAINING JUST TO THE EAST OF OUR AREA. THUS... WILL KEEP ONLY SLIGHT CHANCE POPS ACROSS OUR EAST AS WELL. OVERNIGHT LOWS IN THE MID TO UPPER 60S ARE STILL EXPECTED... WITH GENERALLY PATCHY FOG (FOG... AT LOCATIONS THAT ARE PICKING UP DECENT SHOWERS/STORMS ACROSS THE TRIAD NOW) AND WIDESPREAD LOW STATUS. && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 300 PM WEDNESDAY... A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20 KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY. THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS. LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER 50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 255 AM THURSDAY... SATURDAY AND SUNDAY... A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE. UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE. MONDAY THROUGH WEDNESDAY.... THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK... FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE LOWER 60S WEDNESDAY MORNING. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AS OF 205 AM THURSDAY... A LINE OF SHOWERS AND ISOLATED STORMS THAT EARLIER AFFECTED THE TRIAD TERMINALS WILL CONTINUE TO MOVE SLOWLY EASTWARD AT AROUND 10 MPH...AFFECTING THE KRDU AREA BETWEEN 8-10Z. A GRADUAL WEAKENING/DISSIPATING TREND SHOULD OCCUR AS THE AIR MASS CONTINUES TO STABILIZE WITH NOCTURNAL COOLING...HOWEVER...SO CONFIDENCE OF THE CONVECTION REACHING THE KFAY AND KRWI AREAS IS LOW. OTHERWISE...A CONTINUED MOIST AIR MASS WILL PROMOTE A HIGH CHANCE OF LIFR-IFR CEILINGS THIS MORNING...THOUGH WITH RELATIVE LOWEST CHANCES - AROUND 60 PERCENT - AT TRIAD TERMINALS. THESE CEILINGS WILL LIFT AND SCATTER TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR MASS WILL ALSO CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO DEVELOP THIS AFTERNOON...AND THESE WILL LIKELY CONTINUE UNTIL A COLD FRONT SWEEPS ACROSS CENTRAL NC FROM WEST TO EAST BETWEEN 04-06Z AT TRIAD TERMINALS...TO 09-12Z AT EASTERN ONES. AREAS O FOG OR LOW STRATUS WILL ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY AT KFAY AND KRWI BETWEEN 06-12Z. VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE THROUGH THE HOLIDAY WEEKEND. && .CLIMATE... MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE. RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH RDU 43 / 1967 43 / 1979 GSO 43 / 1956 42 / 1930 .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...BSD SHORT TERM...ELLIS LONG TERM...MLM AVIATION...MWS CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
208 AM EDT THU MAY 23 2013 .SYNOPSIS... A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH WILL MOVE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS OUR REGION THROUGH THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1010 PM WEDNESDAY... ANY SHOWERS AND THUNDERSTORMS FROM THIS AFTERNOON AND EVENING ASSOCIATED WITH THE SEA BREEZE AND OUTFLOW ACROSS THE EASTERN TWO-THIRDS OF THE AREA HAVE DISSIPATED WITH THE LOSS OF DAYTIME HEATING AND RESULTANT STABILIZING BOUNDARY LAYER. CONVECTION THAT FIRED ACROSS THE HIGHER TERRAIN TODAY... HAS GENERALLY STAYED TO THE WEST OF THE REGION WITH A 15 TO 20 KT SOUTH-SOUTHWESTERLY MEAN STEERING FLOW. HOWEVER... A WEST-NORTHWESTERLY OUTFLOW... GENERATED FROM THESE CLUSTERS OF SHOWERS AND STORMS THAT ORIGINATED ALONG THE HIGHER TERRAIN... HAS FINALLY ALLOWED FOR THE DEVELOPMENT OF SHOWERS AND STORMS ACROSS OUR FAR NORTHWESTERN REACHES OF OUR CWA... ALONG THE OUTFLOW. THINK THIS OUTFLOW SHOULD SUPPORT AT LEAST SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS OUR WESTERN PIEDMONT THROUGH 06/07Z... GIVEN 500 TO 1000 J/KG OF SURFACE BASED CAPE. THEREAFTER... EXPECT BOUNDARY LAYER COOLING SHOULD YIELD A TREND TO ISOLATED SHOWERS AT BEST. ANY SIGNIFICANT S/W ENERGY ROTATING THROUGH THE CYCLONIC FLOW ALOFT FROM THE APPROACHING MID LEVEL TROUGH WELL TO THE WEST OF THE AREA... INVOF THE MS RIVER THIS EVENING... IS EXPECTED TO PASS TO THE WEST AND NORTH OF THE REGION THUS... PLAN TO TRIM POPS TO SLIGHT CHANCE BY EARLY THURSDAY MORNING ACROSS THE ENTIRE CWA. THIS IS SUPPORTED BY THE LATEST HRRR. HOWEVER... ITS WORTH NOTING THE LATEST HRRR DOES SHOW SOME SHOWERS CURRENTLY OFF THE CAROLINA COAST MOVING ONSHORE OVERNIGHT ACROSS THE COASTAL PLAIN. CURRENT HI-RES MODELS GENERALLY SHOW THIS PRECIP REMAINING JUST TO THE EAST OF OUR AREA. THUS... WILL KEEP ONLY SLIGHT CHANCE POPS ACROSS OUR EAST AS WELL. OVERNIGHT LOWS IN THE MID TO UPPER 60S ARE STILL EXPECTED... WITH GENERALLY PATCHY FOG (FOG... AT LOCATIONS THAT ARE PICKING UP DECENT SHOWERS/STORMS ACROSS THE TRIAD NOW) AND WIDESPREAD LOW STATUS. && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 300 PM WEDNESDAY... A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20 KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY. THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS. LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER 50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... AS OF 310 PM WEDNESDAY... FRIDAY THROUGH SATURDAY NIGHT... A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS WITH THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS DEPICT THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY EARLY AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE BRISK NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION. SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE. FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND 1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S. FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO THE NIGHT. MIN TEMPS 45-50. SATURDAY INTO SATURDAY NIGHT...CANADIAN HIGH PRESSURE OVER THE LOWER GREAT LAKES WILL BUILD/EXTEND INTO OUR REGION SATURDAY INTO SATURDAY NIGHT. THIS WEATHER SYSTEM WILL RESULT IN A DRY WEATHER PATTERN WITH BELOW NORMAL TEMPS. AFTERNOON THICKNESSES PROJECTED TO BE ABOUT 35M BELOW NORMAL...SUPPORTIVE OF TEMPS CLOSE TO 10 DEGREES BELOW NORMAL. ALLOWING FOR WARMTH FROM LATE MAY SUN...EXPECT AFTERNOON HIGH TEMPS IN THE MID-UPPER 70S. MOS GUIDANCE LIKELY TRENDING TOWARD CLIMATOLOGY BY SATURDAY NIGHT. WITH SFC RIDGE OVERHEAD AND CORE OF LOW LEVEL DRY ACROSS THE REGION...TEMPS SHOULD COOL QUICKLY INT EH EVENING THEN STABILIZE. MODEL RH CROSS SECTIONS HINT AT INCREASING MID-HIGH LEVEL CLOUDS OVERNIGHT INTO EARLY SUNDAY. FIRST GLANCE SUGGEST THAT CLOUD COVERAGE MAY INITIALLY BE THIN AND SPOTTY SO COULD SEE DECENT NOCTURNAL COOLING. FAVOR MIN TEMPS A FEW DEGREES COOLER THAN PREVIOUS FORECAST WITH MIN TEMPS IN THE MID-UPPER 40S. SUNDAY INTO MONDAY...DEEP UPPER LEVEL LOW OVER NORTHERN NEW ENGLAND-CANADIAN MARITIME PROVINCES WILL MAINTAIN A NW FLOW OVER THE FORECAST AREA SUNDAY. WEAK PERTURBATIONS IN THIS FLOW ALOFT WORKING WITH AVAILABLE MOISTURE WILL LIKELY CAUSE AN INCREASE IN MID-HIGH LEVEL CLOUDINESS SUNDAY INTO SUNDAY NIGHT...MORE SO ACROSS OUR WEST AND SOUTH SECTIONS AND LEAST IN THE NE. A MODIFYING AIR MASS WILL LEAD TO SLIGHTLY WARMER CONDITIONS WITH AFTERNOON TEMPS IN THE MID-UPPER 70S...AND AND MIN TEMPS IN THE MID 50S. 00Z ECMWF SUGGEST THAT THERE MAY BE ENOUGH AMPLITUDE TO AN APPROACHING MID LEVEL TROUGH TO WARRANT A SLIGHT-SMALL CHANCE POP ACROSS CENTRAL NC MONDAY AFTERNOON-MONDAY EVENING. TUESDAY INTO WEDNESDAY...AN AMPLIFYING MID-UPPER LEVEL RIDGE OVER THE EASTERN HALF OF THE U.S. WILL PLACE CENTRAL NC BACK INTO A SUMMER-LIKE PATTERN WITH A SFC HIGH ANCHORED OFFSHORE BUT EXTENDING WESTWARD INTO THE SE U.S. THIS SUGGEST A RETURN TO WARM AND SLIGHTLY HUMID CONDITIONS WITH AFTERNOON TEMPS IN THE LOW-MID 80S AND MIN TEMPS 60-65. CONVECTION APPEARS TO BE DIURNALLY DRIVEN...ADDED BY A SEABREEZE TO SE AND NW FLOW ALOFT SENDING CONVECTION OFF THE HIGHER TERRAIN INTO THE WESTERN PIEDMONT. POPS NO HIGHER THAN SLIGHT CHANCE-SMALL CHANCE AT THIS TIME...CONFINED TO THE AFTERNOON-EVENING HOURS. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AS OF 205 AM THURSDAY... A LINE OF SHOWERS AND ISOLATED STORMS THAT EARLIER AFFECTED THE TRIAD TERMINALS WILL CONTINUE TO MOVE SLOWLY EASTWARD AT AROUND 10 MPH...AFFECTING THE KRDU AREA BETWEEN 8-10Z. A GRADUAL WEAKENING/DISSIPATING TREND SHOULD OCCUR AS THE AIR MASS CONTINUES TO STABILIZE WITH NOCTURNAL COOLING...HOWEVER...SO CONFIDENCE OF THE CONVECTION REACHING THE KFAY AND KRWI AREAS IS LOW. OTHERWISE...A CONTINUED MOIST AIR MASS WILL PROMOTE A HIGH CHANCE OF LIFR-IFR CEILINGS THIS MORNING...THOUGH WITH RELATIVE LOWEST CHANCES - AROUND 60 PERCENT - AT TRIAD TERMINALS. THESE CEILINGS WILL LIFT AND SCATTER TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR MASS WILL ALSO CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO DEVELOP THIS AFTERNOON...AND THESE WILL LIKELY CONTINUE UNTIL A COLD FRONT SWEEPS ACROSS CENTRAL NC FROM WEST TO EAST BETWEEN 04-06Z AT TRIAD TERMINALS...TO 09-12Z AT EASTERN ONES. AREAS O FOG OR LOW STRATUS WILL ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY AT KFAY AND KRWI BETWEEN 06-12Z. VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE THROUGH THE HOLIDAY WEEKEND. && .CLIMATE... MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE. RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH RDU 43 / 1967 43 / 1979 GSO 43 / 1956 42 / 1930 .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...BSD SHORT TERM...ELLIS LONG TERM...WSS AVIATION...MWS CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
901 PM EDT FRI MAY 24 2013 .SYNOPSIS... CHILLY HIGH PRESSURE TAKES CHARGE TONIGHT INTO SATURDAY. WARM FRONT LIFT NORTH INTO THE OHIO VALLEY AND WEST VIRGINIA EARLY TUESDAY. A WARMING TREND EXPECTED MEMORIAL DAY THROUGH NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 9 PM UPDATE. STILL GOING WITH A FROST SCENARIO FOR THE LOW LANDS UNDER A FROST ADVISORY. DEWPOINTS ACROSS THE NORTH ARE NOW IN THE LOW TO MID 30S ON A DECREASING NORTH WIND. WHILE THE MAJOR CITIES MAY ESCAPE FROST...THE OUTLYING AREAS AND FAVORED LOW SPOTS ARE INCREASINGLY LIKELY FOR SOME FROST. WILL MAKE NO CHANGE TO HEADLINES NOR CURRENT FORECAST. PREVIOUS DISCUSSION... VERY TOUGH FCST TONIGHT REGARDING FROST/FREEZE POTENTIAL. DWPTS CURRENTLY STRADDLING THE MARGINAL THRESHOLD FOR FROST TONIGHT GIVEN AFTN MIXING. NOT SURE IF THESE GO LWR NEXT FEW HRS BEFORE RECOVERING THIS EVE. GUIDANCE FOR METRO AREAS IN THE LOWLANDS RUN 32 TO 40F FROM KHTS TO KCRW. H925 WINDS STAY UP ARND 20 KTS OVERNIGHT AS SFC HIGH BUILDS IN TO ALLOW WINDS AT THE GROUND TO TRY TO GO CALM. ALL OF THIS COMPLICATES MATTERS FOR EXPANDING FROST ADV. HOWEVER...GIVEN TIME OF YEAR AND FACT THAT MOST FOLKS HAVE SOME OF THEIR VEGGIES IN THE GROUND ALONG WITH ANNUAL PLANT INVESTMENTS...FELT PRUDENT TO LEAN A LITTLE LIBERAL AND EXPAND TO ENCOMPASS REST OF CWA SAVE FOR S COAL FIELDS TO SW VA. OUTLYING AREAS WILL SEE BEST SHOT OF FROST. HEADLINE SHOULD GARNER MORE ATTENTION FOR FOLKS TO TAKE PRECAUTIONS TO BE ON SAFE SIDE. ALSO EXPANDED FRZ WARNING TO RALEIGH BASED ON GUIDANCE RANGING FROM 28F TO 33F. THEY WILL HAVE GET UNDER INVERSION THOUGH GIVEN H925 WINDS OFF MDLS OVERNIGHT. OTHER CONCERN IS STRATUS OVERNIGHT ACROSS THE N. NAM HAS BEEN WAY TOO FAST IN ERADICATING THE LLVL MOISTURE VS RUC WHICH HAS BEEN PRETTY STEADY. RUC SHOWS CLDS LIFTING AND SCT THIS EVE ACROSS THE N BEFORE REDEVELOPING IN N MTNS BY 06Z. NAM KEEPS ENTIRE COLUMN DRY BUT HAS NOT HANDLED TDY WELL AT ALL. SO WILL LEAN TOWARD RUC AND REDEVELOP SOME STRATUS IN N MTNS LATE TONIGHT. THIS MAY KEEP TEMPS UP TONIGHT ESPECIALLY IN VALLEYS...BUT STILL FEEL AOB FRZ TEMPS WILL BE REALIZED. UPR TROF AXIS SHIFTS TO E COAST ON SAT WITH SOME RECOVERY IN TEMPS COMPARED TO TDY. INHERITED TEMPS LOOKED GOOD AND ONLY NEEDED TWEAKING SOME...MAINLY ACROSS THE N. && .SHORT TERM /SUNDAY THROUGH MONDAY/... MADE MODIFICATIONS TO THE SHORT TERM FORECAST AS FOLLOWS: HIGH PRESSURE WILL BE IN CONTROL THROUGH THE WEEKEND...KEEPING DRY CONDITIONS AREAWIDE. MODELS SHOW A MID LEVEL SHORTWAVE...EVIDENT IN H5 CHARTS...UNDER NORTHWEST FLOW ALOFT...MOVING ACROSS SOUTHERN OH...SOUTHEAST INTO NORTHWEST KY. REMOVED ANY POPS FOR THE WEEKEND AS MOISTURE LOOKS VERY LIMITED OVER WV. IN FACT...THERE COULD BE SOME CLEARING SATURDAY NIGHT INTO SUNDAY MORNING...KEEPING TEMPERATURES AT OR JUST BELOW FREEZING OVER POCAHONTAS AND RANDOLPH COUNTIES. INCLUDED PATCHY FROST OVER NORTHEAST MOUNTAINS. HIGH PRESSURE MOVES EAST OVER THE MID ATLANTIC STATES KEEPING INFLUENCE OVER WV FOR A DRY SUNDAY THROUGH MONDAY NIGHT. MINOR CHANGES TO TEMPERATURES THROUGH THE PERIOD...PERHAPS A COUPLE DEGREES LOWER CLOSER TO THE COOLER MET. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ANOTHER SHORTWAVE UNDER NORTHWEST FLOW ALOFT PASSES ACROSS SOUTHEAST OH AND WV MONDAY AND TUESDAY. AT THE SAME TIME...A WARM FRONT LIFTS NORTH INTO SOUTHERN OH...ACROSS WV AND VA ORIENTED WEST TO EAST BY 12Z TUESDAY. THESE TWO FEATURES WILL BE CAPABLE TO PRODUCE SHOWERS AND STORMS LATE MONDAY INTO TUESDAY AS THE WARM FRONT MOVES NORTH OF THE AREA BY EARLY WEDNESDAY. INCREASED POPS TO CHANCE INCLUDING THUNDER IN WEATHER GRIDS ACCORDINGLY. HIGH PRESSURE TAKES CONTROL BY EARLY WEDNESDAY PROVIDING DRY WEATHER WITH A SLOW WARMING TREND THROUGH THE REST OF THE WEEK. TWEAKED COUPLE OF DEGREES DOWN FROM HPC GUIDANCE IN THE EXTENDED PERIODS. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... EXCEPT FOR SOME NORTHERN WEST VIRGINIA HIGH ELEVATION MVFR CLOUDS OVERNIGHT...EXPECT VFR MOSTLY CLEAR THRU THE PERIOD...AS HIGH PRESSURE SETTLES OVER THE REGION. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE...MEDIUM TO HIGH. ALTERNATE SCENARIOS: NONE. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 05/25/13 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M M M M M M M M M M M PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H M M M H H H H H AFTER 00Z SUNDAY... IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ005>011- 013>020-026>032-039-040. FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ035>038- 046-047. OH...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR OHZ066-067- 075-076-083>087. KY...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR KYZ101>103- 105. VA...NONE. && $$ SYNOPSIS...ARJ/30 NEAR TERM...JMV/30 SHORT TERM...ARJ LONG TERM...ARJ AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
748 PM EDT FRI MAY 24 2013 .SYNOPSIS... CHILLY HIGH PRESSURE TAKES CHARGE TONIGHT INTO SATURDAY. WARM FRONT LIFT NORTH INTO THE OHIO VALLEY AND WEST VIRGINIA EARLY TUESDAY. A WARMING TREND EXPECTED MEMORIAL DAY THROUGH NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY NIGHT/... VERY TOUGH FCST TONIGHT REGARDING FROST/FREEZE POTENTIAL. DWPTS CURRENTLY STRADDLING THE MARGINAL THRESHOLD FOR FROST TONIGHT GIVEN AFTN MIXING. NOT SURE IF THESE GO LWR NEXT FEW HRS BEFORE RECOVERING THIS EVE. GUIDANCE FOR METRO AREAS IN THE LOWLANDS RUN 32 TO 40F FROM KHTS TO KCRW. H925 WINDS STAY UP ARND 20 KTS OVERNIGHT AS SFC HIGH BUILDS IN TO ALLOW WINDS AT THE GROUND TO TRY TO GO CALM. ALL OF THIS COMPLICATES MATTERS FOR EXPANDING FROST ADV. HOWEVER...GIVEN TIME OF YEAR AND FACT THAT MOST FOLKS HAVE SOME OF THEIR VEGGIES IN THE GROUND ALONG WITH ANNUAL PLANT INVESTMENTS...FELT PRUDENT TO LEAN A LITTLE LIBERAL AND EXPAND TO ENCOMPASS REST OF CWA SAVE FOR S COAL FIELDS TO SW VA. OUTLYING AREAS WILL SEE BEST SHOT OF FROST. HEADLINE SHOULD GARNER MORE ATTENTION FOR FOLKS TO TAKE PRECAUTIONS TO BE ON SAFE SIDE. ALSO EXPANDED FRZ WARNING TO RALEIGH BASED ON GUIDANCE RANGING FROM 28F TO 33F. THEY WILL HAVE GET UNDER INVERSION THOUGH GIVEN H925 WINDS OFF MDLS OVERNIGHT. OTHER CONCERN IS STRATUS OVERNIGHT ACROSS THE N. NAM HAS BEEN WAY TOO FAST IN ERADICATING THE LLVL MOISTURE VS RUC WHICH HAS BEEN PRETTY STEADY. RUC SHOWS CLDS LIFTING AND SCT THIS EVE ACROSS THE N BEFORE REDEVELOPING IN N MTNS BY 06Z. NAM KEEPS ENTIRE COLUMN DRY BUT HAS NOT HANDLED TDY WELL AT ALL. SO WILL LEAN TOWARD RUC AND REDEVELOP SOME STRATUS IN N MTNS LATE TONIGHT. THIS MAY KEEP TEMPS UP TONIGHT ESPECIALLY IN VALLEYS...BUT STILL FEEL AOB FRZ TEMPS WILL BE REALIZED. UPR TROF AXIS SHIFTS TO E COAST ON SAT WITH SOME RECOVERY IN TEMPS COMPARED TO TDY. INHERITED TEMPS LOOKED GOOD AND ONLY NEEDED TWEAKING SOME...MAINLY ACROSS THE N. && .SHORT TERM /SUNDAY THROUGH MONDAY/... MADE MODIFICATIONS TO THE SHORT TERM FORECAST AS FOLLOWS: HIGH PRESSURE WILL BE IN CONTROL THROUGH THE WEEKEND...KEEPING DRY CONDITIONS AREAWIDE. MODELS SHOW A MID LEVEL SHORTWAVE...EVIDENT IN H5 CHARTS...UNDER NORTHWEST FLOW ALOFT...MOVING ACROSS SOUTHERN OH...SOUTHEAST INTO NORTHWEST KY. REMOVED ANY POPS FOR THE WEEKEND AS MOISTURE LOOKS VERY LIMITED OVER WV. IN FACT...THERE COULD BE SOME CLEARING SATURDAY NIGHT INTO SUNDAY MORNING...KEEPING TEMPERATURES AT OR JUST BELOW FREEZING OVER POCAHONTAS AND RANDOLPH COUNTIES. INCLUDED PATCHY FROST OVER NORTHEAST MOUNTAINS. HIGH PRESSURE MOVES EAST OVER THE MID ATLANTIC STATES KEEPING INFLUENCE OVER WV FOR A DRY SUNDAY THROUGH MONDAY NIGHT. MINOR CHANGES TO TEMPERATURES THROUGH THE PERIOD...PERHAPS A COUPLE DEGREES LOWER CLOSER TO THE COOLER MET. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ANOTHER SHORTWAVE UNDER NORTHWEST FLOW ALOFT PASSES ACROSS SOUTHEAST OH AND WV MONDAY AND TUESDAY. AT THE SAME TIME...A WARM FRONT LIFTS NORTH INTO SOUTHERN OH...ACROSS WV AND VA ORIENTED WEST TO EAST BY 12Z TUESDAY. THESE TWO FEATURES WILL BE CAPABLE TO PRODUCE SHOWERS AND STORMS LATE MONDAY INTO TUESDAY AS THE WARM FRONT MOVES NORTH OF THE AREA BY EARLY WEDNESDAY. INCREASED POPS TO CHANCE INCLUDING THUNDER IN WEATHER GRIDS ACCORDINGLY. HIGH PRESSURE TAKES CONTROL BY EARLY WEDNESDAY PROVIDING DRY WEATHER WITH A SLOW WARMING TREND THROUGH THE REST OF THE WEEK. TWEAKED COUPLE OF DEGREES DOWN FROM HPC GUIDANCE IN THE EXTENDED PERIODS. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... EXCEPT FOR SOME NORTHERN WEST VIRGINIA HIGH ELEVATION MVFR CLOUDS OVERNIGHT...EXPECT VFR MOSTLY CLEAR THRU THE PERIOD...AS HIGH PRESSURE SETTLES OVER THE REGION. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE...MEDIUM TO HIGH. ALTERNATE SCENARIOS: NONE. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 05/25/13 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M M M M M M M M M M M PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H M M M H H H H H AFTER 00Z SUNDAY... IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ005>011- 013>020-026>032-039-040. FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ035>038- 046-047. OH...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR OHZ066-067- 075-076-083>087. KY...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR KYZ101>103- 105. VA...NONE. && $$ SYNOPSIS...ARJ/30 NEAR TERM...30 SHORT TERM...ARJ LONG TERM...ARJ AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
718 PM EDT FRI MAY 24 2013 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE WESTERN GREAT LAKES WILL MOVE LITTLE THROUGH THE WEEKEND...THEN SLIDE TO THE EAST COAST MONDAY AND TUESDAY. A WARM FRONT WILL DEVELOP OVER THE MISSISSIPPI VALLEY BY MONDAY AND LIFT NORTH ACROSS THE AREA ON TUESDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MADE MINOR ADJUSTMENTS TO THE HOURLY TEMPERATURES AND SKY COVER THIS EVENING FOR THE EARLY EVENING UPDATE. CALLED IT "CLEARING" FOR THE NE OH/NW PA COUNTIES...OTHERWISE NO CHANGES TO THE CURRENT FORECAST. EARLIER DISCUSSION... GIVEN THE TIME OF YEAR AND IMPACT AND HAVE GONE WITH FROST AND FREEZE HEADLINES FOR THE ENTIRE AREA. IT APPEARS THAT CLEARING WILL RAPIDLY OCCUR THIS EVENING. WINDS SHOULD ALSO LESSEN. IF SPEEDS STAY MORE THAN 5 OR 6 MPH OVERNIGHT FREEZING TEMPS WILL BE HARD TO ACHIEVE. IF FREEZING TEMPS DO OCCUR IT WILL BE ONE OF THE LATEST FREEZES EVER AT ALL OF THE CLIMATE SITES. TEMPS REMAIN IN THE 40S MOST AREAS AND SHOULD DROP QUICKLY AFTER SUNSET. SOME INDICATION THAT HIGH CLOUDS COULD SPILL INTO WESTERN AREAS LATE TONIGHT. GIVEN THE STRENGTH OF THE HIGH THIS COULD BE A LITTLE OVERDONE SO HAVE TAKEN THE FROST HEADLINE ALL THE WAY TO KTOL AND KFDY. LATEST HRRR HAS SURFACE TEMPS TO 34 DEGREES BY 04Z OVER MOST OF INLAND NE OH AND NW PA. IF THAT OCCURS FROST IS LIKELY BY EARLY MORNING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/... DRY HIGH PRESSURE WILL DOMINATE THROUGH THE HOLIDAY WEEKEND. THE AREA WILL REMAIN COOL WITH ONLY VERY SLOWLY MODERATING TEMPERATURES. WILL LIKELY NEED MORE FROST HEADLINES SATURDAY NIGHT IN THE EAST. EXPECT TEMPS TO STRUGGLE TO GET ABOVE 60 ON SATURDAY AND OUT OF THE LOWER AND MIDDLE 60S ON SUNDAY. TEMPERATURE MAY GET TO 70 ON MONDAY BUT THAT WILL STILL BELOW NORMAL. MODELS HAVE BEEN SHOWING A SYSTEM MOVING OUT OF THE PLAINS MONDAY. A WARM FRONT FROM THIS SYSTEM WILL BEGIN TO IMPACT THE AREA MONDAY NIGHT AND HAVE PUT SOME WARM AIR ADVECTION PRECIP IN THE WEST MONDAY NIGHT. THINK DRY WEATHER WILL PREVAIL IN THE EAST TILL AFTER THE SHORT TERM PERIOD. GIVEN A LOOK AT UPSTREAM SATELLITE TODAY SKIES SHOULD BE ALMOST COMPLETELY CLEAR ON SATURDAY WITH JUST SOME HIGH CLOUDS THE REMAINDER OF THE WEEKEND. HAVE TRENDED TO COOL SIDE OF GUIDANCE THROUGH THE PERIOD. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE TUESDAY AND TUESDAY NIGHT AS A WARM FRONT LIFTS THROUGH. IN THE WARM AIR MASS WEDNESDAY THROUGH FRIDAY THERE COULD BE SOME POP UP SHOWERS AND THUNDERSTORMS...CONTINUING THE 20 POPS. OTHERWISE A WARMING TREND WITH HIGHS ABOVE NORMAL. USED A BLEND OF GUIDANCE...ESPECIALLY HPC. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE BUILDING EAST AT THIS TIME WITH CLEAR SKIES WEST HALF AND CLEARING SKIES EXPECTED IN THE EAST HALF. CLOUDS ARE DIURNAL IN NATURE AND SHOULD DISSIPATE AFTER SUNSET. WINDS MAY TAKE A LITTLE WHILE TO DIMINISH TO LIGHT AND VARIABLE OVERNIGHT. EXPECTING AN INCREASE IN WINDS TO 10 KNOTS FROM CLEVELAND TO MANSFIELD WEST AND TO 15 KNOTS POSSIBLE EAST OF THAT LINE DURING THE DAY. MAINLY CIRRUS EXPECTED TO MOVE EAST OVER THE AREA LATE TONIGHT INTO TOMORROW. OTHERWISE...VFR. .OUTLOOK...NON VFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY NIGHT THROUGH TUESDAY. && .MARINE... DROPPING THE SMALL CRAFT ADVISORY ON THE EXTREME WEST END OF THE LAKE AS THE HIGH IS BUILDING IN. OTHERWISE NO CHANGES TO THE HEADLINES. THE ONLY CONCERN IS THAT THE WAVES COULD BE NEAR SMALL CRAFT ADVISORY CRITERIA SATURDAY AFTERNOON IN THE NORTHWEST FLOW...THIS WILL HAVE TO BE MONITORED. OTHERWISE NOT EXPECTING CONDITIONS TO MEET SMALL CRAFT ADVISORY CONDITIONS ON THE LAKE IN A MAINLY SOUTHWEST FLOW. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR OHZ003-006>012-017>019-027-028-036-089. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR OHZ013-014-020>023-029>033-037-038-047. PA...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR PAZ001. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR PAZ002-003. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ146>149. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LEZ144-145. && $$ SYNOPSIS...KOSARIK/KUBINA NEAR TERM...KOSARIK/KUBINA SHORT TERM...KUBINA LONG TERM...KIELTYKA AVIATION...LOMBARDY MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
121 AM EDT THU MAY 23 2013 .SYNOPSIS... AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... 0500 UTC UPDATE...POPS WERE REALIGNED TO CONCUR WITH RADAR TRENDS...MOVING A LINE OF CONVECTION ACROSS INTERSTATE 77 OVER THE NET FEW HOURS...ANOTHER CLUSTER OF STORMS ACROSS THE UPPER SAVANNAH RIVER VALLEY...AND A THIRD GROUP OF STORMS FROM THE GA MOUNTAINS INTO SC. WINDS WERE UPDATED WITH A BLEND OF THE LATEST ADJMAV AND NAM...FAVORING THE LATER FOR HIGHER WINDS IN THE MOUNTAINS. VISIBILITY WAS UPDATED FORM OBSERVATIONS AND A BLEND OF THE ADJMAV AND ADJMET...LOWERED SLIGHTLY TOWARD THE LAMP GUIDANCE. AS OF 1045 PM...BROKEN MULTICELL LINE OF THUNDERSTORMS CONTINUES TO MOVE TO THE EAST NORTHEAST ACROSS THE UPSTATE IN ASSOCIATION WITH CONVERGENCE NEAR FRONTAL BOUNDARY. ELSEWHERE...DISCRETE PULSE SHOWERS AND THUNDERSTORMS WERE PRESENT ACROSS PORTIONS OF THE NORTH CAROLINA FOOTHILLS/PIEDMONT. THE MAIN THREATS WITH ANY OF THESE THUNDERSTORMS ARE BRIEF HEAVY RAINFALL...LARGE HAIL...DAMAGING WINDS...AND FREQUENT CLOUD TO GROUND LIGHTNING. AS FOR THE FCST...THE ACTIVITY CURRENTLY EXTENDING ACROSS THE WESTERN CWFA SHOULD MOVE EASTWARD ACROSS THE CWFA GRADUALLY DIMINISHING IN INTENSITY AS INSTABILITY WANES. GENERALLY CHANGED POPS TO REFLECT THIS WAVE OF ACTIVITY BEING FOLLOWED BY MUCH LOWER POPS IN SCHC TO LOW CHC RANGE DUE TO CONTINUED PRESENCE OF UPSTREAM ACTIVITY. ADJUSTED TEMPERATURE TRENDS FURTHER BY LOWERING TEMPS ACROSS THE NORTH CAROLINA PIEDMONT DUE TO OUTFLOW BOUNDARIES FROM EARLIER CONVECTION SPREADING ACROSS THIS REGION. REMAINDER OF PREVIOUS DISCUSSION... AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO UPDATE FIRST FEW HRS. AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY. FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD. THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE A FEW DEGREES COOLER. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS... AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR SO. A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5 TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR ANY PRECIPITATION. MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA... PARTICULARLY IN THE AFTERNOON. HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL HAVE TO MONITOR TRENDS. HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON TAP. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES. HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED. RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED. SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME GUSTY. ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY. EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS. ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS THURSDAY EVENING IN NW UPSLOPE FLOW. OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-05Z KCLT HIGH 84% HIGH 90% HIGH 100% HIGH 100% KGSP MED 79% HIGH 88% HIGH 100% HIGH 100% KAVL MED 70% HIGH 88% HIGH 100% HIGH 97% KHKY LOW 56% HIGH 83% HIGH 100% HIGH 100% KGMU MED 73% HIGH 83% HIGH 100% HIGH 100% KAND MED 69% HIGH 94% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...SBK NEAR TERM...CDG/JAT/PM/WIMBERLEY SHORT TERM...TS LONG TERM...SBK AVIATION...JAT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1107 PM CDT FRI MAY 24 2013 .UPDATE... ISSUED AT 930 PM CDT FRI MAY 24 2013 LATE AFTERNOON CONVECTION ROUND HAS MOVED EAST OF THE AREA WHILE LEAVING VERY SPOTTY LIGHT SHOWERS FAR EAST. NEXT ROUND THE DEVELOPED OVER WESTERN AND CENTRAL NE HAS BEEN TURNING MORE EAST NORTHEAST WITH THE STRONGER CONVECTION AND EXPECT THIS TREND TO CONTINUE. HOWEVER...FEEL THE SHORT TERM RAP CONTINUES TO BE MORE IN TUNE WITH THE THREAT OF LIGHT TO MODERATE CONVECTION DEVELOPING NORTH OF THIS AREA AND AFFECTING ESPECIALLY THE SOUTHERN EDGE OF THE FORECAST AREA...MORE FAR SOUTHEAST VERY LATE TONIGHT. THE NAM CONTINUES TO DOWNPLAY THIS THREAT. OVERALL LOW TEMPERATURES LOOK OK WITH HOURLY READING EXPECTED TO GRADUALLY EVEN OUT...THAT IS THE TEMPERATURES CONTRAST FROM SOUTH TO NORTH SHOULD DECREASE A LITTLE. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 332 PM CDT FRI MAY 24 2013 SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CWA WITH THE MOST CONCENTRATED AREA NORTH OF INTERSTATE 90 AND EAST OF INTERSTATE 29 THIS EVENING. WITH THE WAVE THAT IS AIDING IN THIS DEVELOPMENT MOVING NORTHEAST SUSPECT THE TREND TO THE EAST AND NORTH WITH THIS ACTIVITY WILL CONTINUE. SHEAR AND INSTABILITY NOT ENOUGH FOR SEVERE THUNDERSTORMS BUT SOME VERY SMALL HAIL POSSIBLE WITH THE STRONGER STORMS. BETWEEN ABOUT 3Z TO 6Z THE LOW LEVEL JET INCREASES QUITE A BIT IN CENTRAL NEBRASKA AND BEGINS TO FOCUS THE BEST CONVERGENCE/ADVECTION TOWARDS THE MISSOURI RIVER ALONG THE SOUTH DAKOTA NEBRASKA BORDER. THE WEAKEST CIN AND HIGHEST CAPE VALUES SUGGEST THAT A PARCEL LIFTED FROM ABOUT 850MB TO 800MB WOULD HAVE ABOUT 1500 J/KG TO WORK WITH. WHILE THE EFFECTIVE SHEAR IS QUITE WEAK SOME NICKEL TO DIME SIZED HAIL WOULD BE POSSIBLE NEAR THE MISSOURI RIVER. WITH FAIRLY SLOW STORM MOTION ANY STORMS THAT COULD DEVELOP WOULD HAVE THE POTENTIAL TO PRODUCE SOME HEAVIER RAINFALL. WILL KEEP THE HIGHEST POPS ALONG THE MISSOURI RIVER INTO NORTHWEST IOWA OVERNIGHT WITH A TREND DOWNWARD IN RAIN AND THUNDERSTORM POTENTIAL ON SATURDAY. OTHER THAN CONVECTIVE BLOW OFF OR SOMETHING THAT ADVECTS IN IT LOOKS LIKE CAPPING WILL KEEP THUNDERSTORMS AT BAY MOST OF THE DAY IN MOST LOCATIONS. STILL EXPECTING QUITE A BIT OF CLOUD COVER AND COOL TEMPERATURES...RANGING FROM THE MID 60S EAST OF THE BUFFALO RIDGE TO 75 TO 80 IN SOUTH CENTRAL SOUTH DAKOTA. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 332 PM CDT FRI MAY 24 2013 MODELS SUGGEST THAT A PAIR OF WAVES MAY BEGIN NOSING INTO BLACK HILLS AREA SATURDAY AFTERNOON AND AGAIN SUNDAY AFTERNOON... TRIGGERING CONVECTION TO OUR WEST SATURDAY EVENING AND SOUTHWEST ON SUNDAY EVENING. WITH A QUASI-STATIONARY BOUNDARY DRAPED ACROSS THE REGION...VERY HIGH PRECIPITABLE WATER AMOUNTS THROUGHOUT THE REGION AND A STRENGTHENING LOW LEVEL JET NEAR THE MISSOURI RIVER BOTH NIGHTS...EXPECT SHOWER AND THUNDERSTORM POTENTIAL TO PEAK DURING THE EVENING AND OVERNIGHT HOURS. MAIN CONCERN WITH THIS CONVECTION WOULD BE LOCALLY HEAVY RAINFALL AMOUNTS AND STRONG WIND GUSTS. MARGINALLY SEVERE HAIL WILL ALSO BE POSSIBLE...HOWEVER THIS THREAT WOULD BE MAINLY DURING THE EVENING HOURS. PRECIPITATION CHANCES DO DIMINISH SLIGHTLY DURING THE DAY ON SUNDAY...BUT WILL KEEP SCATTERED MENTION GOING THROUGH THE DAY WITH SOME TIMING UNCERTAINTY. VERY ACTIVE AND WET PATTERN IS EXPECTED TO PERSIST THROUGH THE ENTIRE MID AND LONG RANGE WITH PRECIPITATION IN THE FORECAST EACH PERIOD...INCLUDING MEMORIAL DAY. STILL SEEING QUITE A BIT OF UNCERTAINTY WITH TIMING ALL OF THE SHORTWAVES TRACKING THROUGH THE REGION ALONG THE GENERAL UPPER LEVEL SOUTHWEST FLOW. WEST COAST TROUGHING STARTS NUDGING FURTHER EAST INTO THE HIGH PLAINS LATE WEEK NEXT WEEK...HOWEVER THE SLOW MOVING NATURE OF THIS SYSTEM KEEPS IT...AND PRECIPITATION IN THE FORECAST EVEN THROUGH NEXT WEEKEND. TEMPERATURES WILL WARM A LITTLE TO SLIGHTLY ABOVE NORMAL READINGS AROUND MID WEEK BUT WILL START TO COOL A BIT LATE WEEK WITH POTENTIAL TROUGHING ARRIVING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1103 PM CDT FRI MAY 24 2013 MODELS CONTINUE TO SHOW CEILINGS DETERIORATING INTO MVFR-IFR RANGE LATER TONIGHT AT ALL TAF SITES. STARTING TO SEE HINTS OF MVFR CLOUDS IN EASTERN NEBRASKA AS OF 04Z...SO WILL CONTINUE THIS DOWNWARD TREND IN CEILINGS THROUGH THE FIRST 4-6 HOURS OF TAF PERIOD...WITH NEXT CHANCE OF RAIN EXPANDING INTO SOUTHERN PARTS OF THE AREA ALONG WITH THE LOWER CEILINGS. SOME MID LEVEL INSTABILITY PRESENT AS THE RAIN MOVES INTO SOUTHWEST PARTS OF THE FORECAST AREA...BUT PRECIP MOVES INTO MORE STABLE AIRMASS AS IT PROGRESSES EASTWARD...LEADING TO MORE ISOLATED THUNDER THREAT ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE LEFT MENTION OF THUNDER OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH CANNOT COMPLETELY BE RULED OUT 08Z-15Z...ESPECIALLY AT KSUX. BULK OF MVFR CEILINGS EXPECTED TO BECOME MORE SCATTERED THROUGH THE LATE MORNING/EARLY AFTERNOON SATURDAY...THOUGH WITH MORE ABUNDANT LOW LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS AT TIMES THROUGH THE AFTERNOON. GREATER CHANCE OF MVFR-IFR REDEVELOPMENT SATURDAY EVENING WITH NEXT CHANCE OF CONVECTION SPREADING INTO THE AREA. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE... SHORT TERM...08 LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
930 PM CDT FRI MAY 24 2013 .UPDATE... ISSUED AT 930 PM CDT FRI MAY 24 2013 LATE AFTERNOON CONVECTION ROUND HAS MOVED EAST OF THE AREA WHILE LEAVING VERY SPOTTY LIGHT SHOWERS FAR EAST. NEXT ROUND THE DEVELOPED OVER WESTERN AND CENTRAL NE HAS BEEN TURNING MORE EAST NORTHEAST WITH THE STRONGER CONVECTION AND EXPECT THIS TREND TO CONTINUE. HOWEVER...FEEL THE SHORT TERM RAP CONTINUES TO BE MORE IN TUNE WITH THE THREAT OF LIGHT TO MODERATE CONVECTION DEVELOPING NORTH OF THIS AREA AND AFFECTING ESPECIALLY THE SOUTHERN EDGE OF THE FORECAST AREA...MORE FAR SOUTHEAST VERY LATE TONIGHT. THE NAM CONTINUES TO DOWNPLAY THIS THREAT. OVERALL LOW TEMPERATURES LOOK OK WITH HOURLY READING EXPECTED TO GRADUALLY EVEN OUT...THAT IS THE TEMPERATURES CONTRAST FROM SOUTH TO NORTH SHOULD DECREASE A LITTLE. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 332 PM CDT FRI MAY 24 2013 SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CWA WITH THE MOST CONCENTRATED AREA NORTH OF INTERSTATE 90 AND EAST OF INTERSTATE 29 THIS EVENING. WITH THE WAVE THAT IS AIDING IN THIS DEVELOPMENT MOVING NORTHEAST SUSPECT THE TREND TO THE EAST AND NORTH WITH THIS ACTIVITY WILL CONTINUE. SHEAR AND INSTABILITY NOT ENOUGH FOR SEVERE THUNDERSTORMS BUT SOME VERY SMALL HAIL POSSIBLE WITH THE STRONGER STORMS. BETWEEN ABOUT 3Z TO 6Z THE LOW LEVEL JET INCREASES QUITE A BIT IN CENTRAL NEBRASKA AND BEGINS TO FOCUS THE BEST CONVERGENCE/ADVECTION TOWARDS THE MISSOURI RIVER ALONG THE SOUTH DAKOTA NEBRASKA BORDER. THE WEAKEST CIN AND HIGHEST CAPE VALUES SUGGEST THAT A PARCEL LIFTED FROM ABOUT 850MB TO 800MB WOULD HAVE ABOUT 1500 J/KG TO WORK WITH. WHILE THE EFFECTIVE SHEAR IS QUITE WEAK SOME NICKEL TO DIME SIZED HAIL WOULD BE POSSIBLE NEAR THE MISSOURI RIVER. WITH FAIRLY SLOW STORM MOTION ANY STORMS THAT COULD DEVELOP WOULD HAVE THE POTENTIAL TO PRODUCE SOME HEAVIER RAINFALL. WILL KEEP THE HIGHEST POPS ALONG THE MISSOURI RIVER INTO NORTHWEST IOWA OVERNIGHT WITH A TREND DOWNWARD IN RAIN AND THUNDERSTORM POTENTIAL ON SATURDAY. OTHER THAN CONVECTIVE BLOW OFF OR SOMETHING THAT ADVECTS IN IT LOOKS LIKE CAPPING WILL KEEP THUNDERSTORMS AT BAY MOST OF THE DAY IN MOST LOCATIONS. STILL EXPECTING QUITE A BIT OF CLOUD COVER AND COOL TEMPERATURES...RANGING FROM THE MID 60S EAST OF THE BUFFALO RIDGE TO 75 TO 80 IN SOUTH CENTRAL SOUTH DAKOTA. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 332 PM CDT FRI MAY 24 2013 MODELS SUGGEST THAT A PAIR OF WAVES MAY BEGIN NOSING INTO BLACK HILLS AREA SATURDAY AFTERNOON AND AGAIN SUNDAY AFTERNOON... TRIGGERING CONVECTION TO OUR WEST SATURDAY EVENING AND SOUTHWEST ON SUNDAY EVENING. WITH A QUASI-STATIONARY BOUNDARY DRAPED ACROSS THE REGION...VERY HIGH PRECIPITABLE WATER AMOUNTS THROUGHOUT THE REGION AND A STRENGTHENING LOW LEVEL JET NEAR THE MISSOURI RIVER BOTH NIGHTS...EXPECT SHOWER AND THUNDERSTORM POTENTIAL TO PEAK DURING THE EVENING AND OVERNIGHT HOURS. MAIN CONCERN WITH THIS CONVECTION WOULD BE LOCALLY HEAVY RAINFALL AMOUNTS AND STRONG WIND GUSTS. MARGINALLY SEVERE HAIL WILL ALSO BE POSSIBLE...HOWEVER THIS THREAT WOULD BE MAINLY DURING THE EVENING HOURS. PRECIPITATION CHANCES DO DIMINISH SLIGHTLY DURING THE DAY ON SUNDAY...BUT WILL KEEP SCATTERED MENTION GOING THROUGH THE DAY WITH SOME TIMING UNCERTAINTY. VERY ACTIVE AND WET PATTERN IS EXPECTED TO PERSIST THROUGH THE ENTIRE MID AND LONG RANGE WITH PRECIPITATION IN THE FORECAST EACH PERIOD...INCLUDING MEMORIAL DAY. STILL SEEING QUITE A BIT OF UNCERTAINTY WITH TIMING ALL OF THE SHORTWAVES TRACKING THROUGH THE REGION ALONG THE GENERAL UPPER LEVEL SOUTHWEST FLOW. WEST COAST TROUGHING STARTS NUDGING FURTHER EAST INTO THE HIGH PLAINS LATE WEEK NEXT WEEK...HOWEVER THE SLOW MOVING NATURE OF THIS SYSTEM KEEPS IT...AND PRECIPITATION IN THE FORECAST EVEN THROUGH NEXT WEEKEND. TEMPERATURES WILL WARM A LITTLE TO SLIGHTLY ABOVE NORMAL READINGS AROUND MID WEEK BUT WILL START TO COOL A BIT LATE WEEK WITH POTENTIAL TROUGHING ARRIVING. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 650 PM CDT FRI MAY 24 2013 WILL SEE A BREAK FROM PRECIPITATION THE REMAINDER OF THE EVENING AS FIRST WAVE SHIFTS EAST OF THE FORECAST AREA. MODELS CONTINUE TO SHOW CEILINGS DETERIORATING INTO MVFR RANGE LATER TONIGHT AT ALL TAF SITES WITH AREAS OF IFR CEILINGS AS WELL...SO WILL CONTINUE THIS DOWNWARD TREND IN CEILINGS AFTER 06Z...WITH NEXT CHANCE OF RAIN EXPANDING INTO SOUTHERN PARTS OF THE AREA ALONG WITH THE LOWER CEILINGS. SOME MID LEVEL INSTABILITY PRESENT AS THE RAIN MOVES INTO SOUTHWEST PARTS OF THE FORECAST AREA...BUT PRECIP MOVES INTO MORE STABLE AIRMASS AS IT PROGRESSES EASTWARD...LEADING TO MORE ISOLATED THUNDER THREAT ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE LEFT MENTION OF THUNDER OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH CANNOT COMPLETELY BE RULED OUT 08Z-15Z. BULK OF MVFR CEILINGS EXPECTED TO BECOME MORE SCATTERED THROUGH THE LATE MORNING/MIDDAY HOURS SATURDAY...THOUGH WITH MORE ABUNDANT LOW LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS REDEVELOPING ACROSS THE MISSOURI VALLEY INCLUDING KSUX THROUGH THE AFTERNOON. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE... SHORT TERM...08 LONG TERM... AVIATION...JH
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
841 PM CDT FRI MAY 24 2013 .DISCUSSION...18Z GFS/NAM CYCLE MAINTAIN AN UPPER LOW/TROUGH OVER THE REGION OVERNIGHT MOVG SLOWLY EASTWARD. GFS/NAM ALSO PROG LOW CIN/SIGNIFICANT CAPE OVER THE CWA/MSA OVERNIGHT. PROXIMITY SOUNDINGS DEPICT SIGNIFICANT MSTR (BASED ON PWAT VALUES CONTAMINATION FROM C0NVECTION NOTWITHSTANDING.) WL MAINTAIN LOW POP CONVECTION FOR OVERNIGHT. THE NAM PROG AROUND 20KT ONSHORE FLOW OVERNIGHT AT 925MB ALONG WITH POSITIVE 0-1KM LAPSE RATES ALTHOUGH LESS THAN DRY ADIABATIC. NEVERTHELESS...ANTICIPATE THAT SFC WIND WL REMAIN IN THE 5-10KT RANGE OVER THE CWA OVERNIGHT SUFFICIENT TO LIMIT FOG DEVELOPMENT. EXPECT INCREASING LOW LEVEL CLOUDS AGAIN OVERNIGHT. WIND MAY APPROACH SCEC OVERNIGHT OVER THE COASTAL WATERS OWING TO THE FOREGOING LAPSE RATES/WIND ALOFT. && .PREV DISCUSSION... /ISSUED 702 PM CDT FRI MAY 24 2013/ DISCUSSION...NOTE AVIATION DISCUSSION BELOW. AVIATION...ANTICIPATE THAT ISOLD CONVECTION THIS EVENING GENERALLY EAST OF U.S. ROUTE 281 WL DISSIPATE EARLY TONIGHT. A TRANSITION TO PREDOMINATE MVFR CEILINGS OVERNIGHT. ANTICIPATE THAT FOG WILL BE LIMITED OVERNIGHT OWING TO SUFFICIENT SFC WIND. EXPECT AT LEAST ISOLD CONVECTIVE ACTIVITY TO DEVELOP AGAIN BY MID MORNING SATURDAY AND CONTINUE THROUGH THE EARLY AFTN BEFORE ENDING FROM WEST TO EAST. EXPECT SFC WIND TO INCREASE TO MODERATE/BREEZY BY LATE AFTN. PREV DISCUSSION... /ISSUED 332 PM CDT FRI MAY 24 2013/ SHORT TERM (TONIGHT)...THIS MORNINGS SOUTHERN MCV ASSISTED IN THE DEVELOPMENT OF A LINE OF SHOWERS AND THUNDERSTORMS ACROSS THE WESTERN BRUSH COUNTRY LATE MORNING AND EARLY AFTERNOON. FOLLOWING CLOSE TO THE HIGH RES 18Z HRRR FOR THE REST OF THIS AFTERNOON AND EVENING...WHICH WAS THE ONLY MODEL THAT SEEMED TO HAVE A DECENT HANDLE ON THE SITUATION. THE LINE WILL CONTINUE EAST INTO THE INLAND COASTAL BEND OVER THE NEXT 2 HOURS...THEN POSSIBLY WEAKEN AS OUTFLOW BOUNDARY PUSHES OUT AHEAD OF IT (MAY BE EVIDENCE OF THIS OUTFLOW BOUNDARY ALREADY DEVELOPING. THE ENVIRONMENT ACROSS THE EASTERN BRUSH COUNTRY AND COASTAL BEND IS UNSTABLE...WITH MLCAPE 2000-2500 J/KG AND UNCAPPED. SHEAR IS RELATIVELY WEAK...NEVERTHELESS A FEW STRONGER STORMS PRODUCING SMALL HAIL AND WIND GUSTS UP TO 50 MPH ARE POSSIBLE OVER THE NEXT COUPLE OF HOURS. CONVECTION SHOULD GRADUALLY END AROUND OR AFTER SUNSET. LONG TERM (SATURDAY THROUGH FRIDAY)...WEAK SHORTWAVES WILL CONTINUE TO AFFECT SOUTH TEXAS ON SATURDAY AND INTO SUNDAY. MODELS ALL INDICATE ENERGY WITH THESE SHORTWAVES...BUT ARE A BIT DIFFERENT IN THE FINER DETAILS. STILL THINK THE NEXT WAVE TOMORROW COULD BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE AREA. HAVE SPREAD THE SLIGHT CHANCE AREA FARTHER EAST GIVEN INCREASED MOISTURE FARTHER EAST THAN PREVIOUS MODELS HAD INDICATED. HAVE A LINGERING 10 POP WITH SLIGHT CHANCE WORDING FOR SUNDAY AS A SHORTWAVE WEAKER THAN THE OTHERS PASSES BY...BUT GUIDANCE STILL INDICATING SOME QPF ACROSS THE AREA. FOR MONDAY AND TUESDAY HIGH PRESSURE RIDGE BUILDS STRONGER ACROSS THE AREA WHILE 850 THETA E RIDGE SHIFTS WESTWARD. THIS WILL DRY THINGS OUT A BIT IN THE MID LEVELS AND ALLOW TEMPERATURES TO INCREASE. INCREASED PRESSURE GRADIENT WITH RESULTING FROM THE STRENGTHENING RIDGE TO THE EAST WILL ALSO INCREASE WINDS ACROSS THE AREA EARLY IN THE WEEK. SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE BY MID-WEEK. AN UPPER LEVEL TROUGH WILL BE DIGGING INTO THE WESTERN US BY MID WEEK AS WELL. MODEL SOLUTIONS HAVE NOT BEEN CONSISTENT WITH THE AMPLITUDE OF THIS TROUGH. SOME MODELS INDICATE A PRETTY DEEP TROUGH DIGGING AS FAR SOUTH AS NORTHERN MEXICO. OTHER MODELS SHOW A MUCH WEAKER TROUGH. NOT CONFIDENT YET IN CHANCES FOR PRECIP THURSDAY/FRIDAY...BUT WILL LEAVE 20 POPS FROM PREVIOUS FORECAST AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 76 89 75 90 75 / 30 10 10 10 10 VICTORIA 74 88 72 90 71 / 30 20 10 10 10 LAREDO 75 92 74 96 74 / 30 20 10 10 10 ALICE 75 89 73 92 73 / 30 20 10 10 10 ROCKPORT 75 87 75 88 76 / 30 10 10 10 10 COTULLA 74 91 72 95 72 / 30 30 10 10 10 KINGSVILLE 76 90 75 91 74 / 30 10 10 10 10 NAVY CORPUS 75 86 75 87 76 / 30 10 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ WC/87...SHORT TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
702 PM CDT FRI MAY 24 2013 .DISCUSSION...NOTE AVIATION DISCUSSION BELOW. && .AVIATION...ANTICIPATE THAT ISOLD CONVECTION THIS EVENING GENERALLY EAST OF U.S. ROUTE 281 WL DISSIPATE EARLY TONIGHT. A TRANSITION TO PREDOMINATE MVFR CEILINGS OVERNIGHT. ANTICIPATE THAT FOG WILL BE LIMITED OVERNIGHT OWING TO SUFFICIENT SFC WIND. EXPECT AT LEAST ISOLD CONVECTIVE ACTIVITY TO DEVELOP AGAIN BY MID MORNING SATURDAY AND CONTINUE THROUGH THE EARLY AFTN BEFORE ENDING FROM WEST TO EAST. EXPECT SFC WIND TO INCREASE TO MODERATE/BREEZY BY LATE AFTN. && .PREV DISCUSSION... /ISSUED 332 PM CDT FRI MAY 24 2013/ SHORT TERM (TONIGHT)...THIS MORNINGS SOUTHERN MCV ASSISTED IN THE DEVELOPMENT OF A LINE OF SHOWERS AND THUNDERSTORMS ACROSS THE WESTERN BRUSH COUNTRY LATE MORNING AND EARLY AFTERNOON. FOLLOWING CLOSE TO THE HIGH RES 18Z HRRR FOR THE REST OF THIS AFTERNOON AND EVENING...WHICH WAS THE ONLY MODEL THAT SEEMED TO HAVE A DECENT HANDLE ON THE SITUATION. THE LINE WILL CONTINUE EAST INTO THE INLAND COASTAL BEND OVER THE NEXT 2 HOURS...THEN POSSIBLY WEAKEN AS OUTFLOW BOUNDARY PUSHES OUT AHEAD OF IT (MAY BE EVIDENCE OF THIS OUTFLOW BOUNDARY ALREADY DEVELOPING. THE ENVIRONMENT ACROSS THE EASTERN BRUSH COUNTRY AND COASTAL BEND IS UNSTABLE...WITH MLCAPE 2000-2500 J/KG AND UNCAPPED. SHEAR IS RELATIVELY WEAK...NEVERTHELESS A FEW STRONGER STORMS PRODUCING SMALL HAIL AND WIND GUSTS UP TO 50 MPH ARE POSSIBLE OVER THE NEXT COUPLE OF HOURS. CONVECTION SHOULD GRADUALLY END AROUND OR AFTER SUNSET. LONG TERM (SATURDAY THROUGH FRIDAY)...WEAK SHORTWAVES WILL CONTINUE TO AFFECT SOUTH TEXAS ON SATURDAY AND INTO SUNDAY. MODELS ALL INDICATE ENERGY WITH THESE SHORTWAVES...BUT ARE A BIT DIFFERENT IN THE FINER DETAILS. STILL THINK THE NEXT WAVE TOMORROW COULD BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE AREA. HAVE SPREAD THE SLIGHT CHANCE AREA FARTHER EAST GIVEN INCREASED MOISTURE FARTHER EAST THAN PREVIOUS MODELS HAD INDICATED. HAVE A LINGERING 10 POP WITH SLIGHT CHANCE WORDING FOR SUNDAY AS A SHORTWAVE WEAKER THAN THE OTHERS PASSES BY...BUT GUIDANCE STILL INDICATING SOME QPF ACROSS THE AREA. FOR MONDAY AND TUESDAY HIGH PRESSURE RIDGE BUILDS STRONGER ACROSS THE AREA WHILE 850 THETA E RIDGE SHIFTS WESTWARD. THIS WILL DRY THINGS OUT A BIT IN THE MID LEVELS AND ALLOW TEMPERATURES TO INCREASE. INCREASED PRESSURE GRADIENT WITH RESULTING FROM THE STRENGTHENING RIDGE TO THE EAST WILL ALSO INCREASE WINDS ACROSS THE AREA EARLY IN THE WEEK. SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE BY MID-WEEK. AN UPPER LEVEL TROUGH WILL BE DIGGING INTO THE WESTERN US BY MID WEEK AS WELL. MODEL SOLUTIONS HAVE NOT BEEN CONSISTENT WITH THE AMPLITUDE OF THIS TROUGH. SOME MODELS INDICATE A PRETTY DEEP TROUGH DIGGING AS FAR SOUTH AS NORTHERN MEXICO. OTHER MODELS SHOW A MUCH WEAKER TROUGH. NOT CONFIDENT YET IN CHANCES FOR PRECIP THURSDAY/FRIDAY...BUT WILL LEAVE 20 POPS FROM PREVIOUS FORECAST AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 76 89 75 90 75 / 30 10 10 10 10 VICTORIA 74 88 72 90 71 / 30 20 10 10 10 LAREDO 75 92 74 96 74 / 30 20 10 10 10 ALICE 75 89 73 92 73 / 30 20 10 10 10 ROCKPORT 75 87 75 88 76 / 30 10 10 10 10 COTULLA 74 91 72 95 72 / 30 30 10 10 10 KINGSVILLE 76 90 75 91 74 / 30 10 10 10 10 NAVY CORPUS 75 86 75 87 76 / 30 10 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ WC/87...AVIATION
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1047 PM CDT FRI MAY 24 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SATURDAY ISSUED AT 248 PM CDT FRI MAY 24 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE STRETCHING FROM HUDSON BAY TO LAKE MICHIGAN TO THE CENTRAL GULF COAST. A FEW STRANDS OF CIRRUS IS INVADING NW WISCONSIN EARLY THIS AFTERNOON...BUT OTHERWISE...CLEAR AND COOL CONDITIONS ARE PREVAILING. LOOKING UPSTREAM...STRENGTHENING RETURN FLOW OVER THE PLAINS IS CREATING A BAND OF SHOWERS AND THUNDERSTORMS OVER EASTERN NORTH AND SOUTH DAKOTA. AS THIS WARM FRONT SHIFTS EAST TONIGHT...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...A JET STREAK...BETWEEN A SE DIVING SHORTWAVE OVER THE EASTERN GREAT LAKES AND A MID-LEVEL RIDGE OVER THE GREAT PLAINS...WILL SLIDE SOUTHEAST ACROSS THE REGION. RIGHT REAR QUAD OF THIS JET STREAK WILL SHIFT OVER NORTH-CENTRAL AND NORTHEAST WISCONSIN AFTER MIDNIGHT. DESPITE VERY DRY AIR IN THE LOW LEVELS...MODELS SPIT OUT A COUPLE BANDS OF PRECIP AS A RESULT OF MID-LEVEL CONVERGENCE/FGEN AND UPPER DIVERGENCE...THOUGH DIFFER IN THEIR PLACEMENT. THE LARGEST BAND WILL BE TIED TO THE PRIMARY BAROCLINIC ZONE OFF TO OUR WEST AND SOUTHWEST...WHICH THE NAM/GFS HAVE TRENDED A BIT TO THE WEST. HOWEVER...THE 12Z MESOMODELS CONTINUE TO PUSH THIS BAND OF PRECIP OVER CENTRAL WISCONSIN BETWEEN 06Z AND 12Z. DO NOT HAVE A GOOD FEEL WHERE THIS BAND WILL END UP. BUT LIGHT LOW LEVEL SE WINDS WILL SUPPLY A STEADY DIET OF DRY AIR...SO PRECIP WILL HAVE TO FALL OUT OF A MID-DECK...AND GIVEN THE WEAK FORCING...CANNOT SEE MUCH MORE THAN SPRINKLES LIKE THE PREVIOUS FORECASTER MENTIONED. GIVEN THE LOW IMPACT AND TO MATCH UP WITH OFFICES TO THE WEST AND NORTH...WILL KEEP THE MENTION OF SPRINKLES OVER CENTRAL WISCONSIN. A LOWERING CLOUD DECK WILL KEEP TEMPS WARMER THAN LAST NIGHT AND WILL GO WITH MID 30S NORTH TO MID 40S SOUTH. PATCHY FROST WILL REMAIN POSSIBLE OVER FAR NORTHERN WISCONSIN. SATURDAY...RIGHT REAR QUAD WILL SLIDE TO THE SOUTH-CENTRAL GREAT LAKES DURING THE MORNING. ANY SPRINKLE ACTIVITY SHOULD BE ENDING EARLY SO IT DOES NOT SEEM WORTH MENTIONING IN THE FORECAST. THE DEPARTING MID-LEVEL CONVERGENCE SHOULD ALLOW DRY AIR TO RETURN TO NORTHEAST WISCONSIN LATE MORNING ONWARD WHEN SHOULD SEE DECREASING CLOUDS. CLOUDS TO HANG LONGER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN...CLOSER TO THE PRIMARY BAROCLINIC ZONE. WITH THE ADDITIONAL CLOUD COVER...TEMPS TO REMAIN NEAR OR SLIGHTLY COOLER THAN TODAYS READINGS...AND WILL RANGE FROM THE UPPER 50S OVER CENTRAL WISCONSIN TO THE MIDDLE 60S OVER NORTHEAST WISCONSIN. .LONG TERM...SATURDAY NIGHT THROUGH FRIDAY ISSUED AT 248 PM CDT FRI MAY 24 2013 GOOD AGREEMENT BETWEEN GUIDANCE IN BIG PICTURE WITH STRENGTHENING RIDGE IN THE EAST WHILE TROF PERSISTS OVER THE WEST. PLEASANT WEATHER IS EXPECTED THROUGH MUCH OF THIS MEMORIAL DAY WEEKEND. AT THE SURFACE DRY HIGH PRESSURE TO THE EAST WILL MAINTAIN EAST TO SOUTHEAST FLOW OVER THE REGION. SOME MODEL DISCONNECT WITH HOW HANDLE SHORT WAVE ACTIVITY EXITING WESTERN TROF INTO THE PLAINS AND WESTERN LAKES LATE THIS HOLIDAY PERIOD. HAVE STAYED TOWARD DRIER EC/GFS...WITH IDEA THAT HIGH WILL KEEP PCPN TO OUR SOUTHWEST SUN AND MON. NAM APPEARS THE OUTLIER...TOO STRONG AND FAST. LIGHT WINDS AND DRY CONDITIONS TO LEAD TO ANOTHER COOL NIGHT FOR NORTHEAST WI...WITH PATCHY FROST OVER PARTS OF FAR NORTHEAST WI. TROF DEEPENS WEST BEGINNING OF NEXT WEEK PUMPING UP RIDGE JUST TO OUR EAST. THIS TO LEAD TO WARMER TEMPS AND INCREASING HUMIDITY AND INSTABILITY AS WARM FRONT LIFTS NORTH TOWARDS...OR THROUGH STATE. AGAIN SOME DISPARITY ON HOW FAR NORTH FRONT WILL GO...WITH EC LINGERING IT OVER NORTHERN WI. COULD BE LOOKING A PERIOD OF ACTIVE WEATHER NEXT WED/THU WITH POSSIBILITY OF PERIODS OF HEAVY RAINFALL AS PW`S INCREASE TO 1.5. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1045 PM CDT FRI MAY 24 2013 MIDDLE AND HIGH CLOUDS WILL MOVE INTO THE AREA OVERNIGHT AND EARLY SATURDAY AND COULD PRODUCE VIRGA OR A BRIEF LIGHT SHOWER OVER CENTRAL OR NORTHCENTRAL WISCONSIN WHILE REMAINING VFR. MOSTLY SUNNY SKIES FORECAST FOR SATURDAY AFTERNOON WITH RELATIVELY LIGHT SURFACE WINDS. GOOD FLYING WEATHER SHOULD CONTINUE THROUGH AT LEAST SUNDAY NIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TE AVIATION.......RDM
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
943 PM CDT FRI MAY 24 2013 .UPDATE... HAVE BROUGHT SLIGHT CHANCE POPS INTO THE FAR WEST A BIT EARLIER THAN PREVIOUS FORECAST...AND MAY HAVE TO UP THE PROBABILITIES IF THE BAND OF SHOWERS AND A FEW THUNDERSTORMS HOLD TOGETHER. THE WARM AIR ADVECTION BAND...TRACKING WITH 700MB FRONTOGENETIC FORCING AND ISENTROPIC LIFT...WILL REACH FAR WESTERN SECTIONS OF IOWA AND LAFAYETTE COUNTIES BETWEEN 11 PM AND 1115 PM. LATEST NAM AND HI- RES SHORT TERM MODELS CONTINUE TO SHOW THE PRECIPITATION WEAKENING/DIMINISHING AS IT MOVES AWAY FROM THE NARROW BAND OF BETTER FORCING AND LOWER CONDENSATION PRESSURE DEFICITS BACK TO THE WEST CLOSER TO THE FOCUSED 850-700 MB WRM ADVECTION. && .AVIATION/06Z TAFS/... WILL KEEP VFR CONDITIONS THROUGH THE FORECAST. WATCHING POTENTIAL FOR LIGHT RAIN SHOWERS TO REACH KMSN AROUND/AFTER 09Z...HOWEVER LATEST RAP SOUNDINGS STILL SHOW THE WARM ADVECTION ONLY MOISTENING THE COLUMN DOWN TO AROUND 6-7K FT...AND VERY DRY BELOW THAT...SO ONLY EXPECTING SPRINKLES AT BEST FOR NOW. INFLUENCE OF HIGH PRESSURE WILL HOLD ANY PRECIPITATION OFF TO THE SOUTHWEST PORTION OF THE CWA...SOUTHWEST OF KLNR OT KJVL...FOR THE REMAINDER OF THE FORECAST. && .PREV DISCUSSION... /ISSUED 315 PM CDT FRI MAY 24 2013/ VERY SHORT TERM...TONIGHT AND SATURDAY. SHORT RANGE MODELS SHOW HIGH PRESSURE SLOWLY SHIFTING EAST OF THE AREA TONIGHT AND SATURDAY. MODELS ARE TRYING TO BRING THE 850MB FOCUSED WARM AIR ADVECTION NORTHEAST INTO THE SOUTHWESTERN PORTIONS OF THE AREA THIS EVENING...THEN IS SHUNTED FURTHER TO THE SOUTHWEST LATER TONIGHT. THIS AREA THEN GRADUALLY PUSHES BACK TOWARD THE SOUTHWEST PORTIONS OF THE AREA SATURDAY. 850MB LOW LEVEL JET NOSE FOCUSES WEST OF THE AREA TONIGHT...BEFORE POINTING MORE INTO CENTRAL TO NORTHEAST IOWA SATURDAY. SOME DISAGREEMENT AMONG THE MODELS WITH THE PLACEMENT OF THESE 850MB FEATURES...AND SUBSEQUENT QPF. ECMWF MOST AGGRESSIVE WITH QPF ACROSS THE SOUTHWEST HALF OF THE AREA TONIGHT...WITH THE OTHERS MAINLY DRY. THE NAM IS MOST AGGRESSIVE SATURDAY IN A SIMILAR AREA...WITH THE OTHER MODELS MAINLY DRY. GIVEN THE DRY AIR LINGERING IN THE LOW LEVELS WITH THE HIGH TO THE EAST...WILL LIMIT POPS TO MAINLY THE SOUTH CENTRAL COUNTIES LATER TONIGHT AND SATURDAY. SHOULD SEE BROKEN TO OVERCAST MID LEVEL CLOUDS SPREAD ACROSS MOST OF THE AREA LATER TONIGHT AND SATURDAY. THESE SHOULD LIMIT LOWS TONIGHT AND LIMIT HIGHS ON SATURDAY. SHORT TERM...SATURDAY NIGHT THROUGH MONDAY. 12Z NAM APPEARS TO BE OUTLIER WITH REGARDS TO MORE NORTHERN PLACEMENT OF WARM FRONT AND MESO-SCALE CONVECTIVE SYSTEM OVER CENTRAL WI SUN NGT AS BAROCLINIC ZONE AND ENHANCED LOW LEVEL CONVERGENCE LIKELY TO BE FURTHER SOUTH AND WEST. NEVER THE LESS...WL CONTINUE TO KEEP SMALL POPS SOUTH AND WEST OF MADISON SAT NGT AND SUN DUE TO NEARBY BAROCLINIC ZONE. BETTER THREAT FOR CONVECTION SUN NGT INTO MONDAY AS NORTHERN EXTENT OF BAROCLINIC ZONES SHIFTS NORTHEAST INTO THE VICINITY ALONG WITH PIECES OF UPSTREAM MCS-INDUCED VORTICITY MOVING NORTHEAST ACROSS SOUTHERN WI. PERSISTENT SOUTHEAST SFC WINDS AND PLENTY OF CLOUDS WILL KEEP TEMPS IN CHECK FOR THE HOLIDAY WEEKEND. LONG TERM...MONDAY NIGHT THROUGH FRIDAY. SHARPENING UPSTREAM LONG WAVE TROFFING OVER WRN CONUS IS EXPECTED EARLY NEXT WEEK AS VIGOROUS PIECE OF ENERGY SLIDES INTO BASE OF TROUGH. THIS WILL RESULT IN INCREASING SOUTHERLY MID LEVEL WINDS WHICH WILL CONTRIBUTE TO THE STRONG FRONTAL BOUNDARY OVER THE CENTRAL CONUS SHIFTING NORTHWARD. MEDIUM RANGE GUIDANCE IN GENERAL AGREEMENT HOWEVER DIFFERENCES OF TIMING OF WARM FRONT PROGRESSION DUE TO AMOUNT AND AREAL EXTENT OF CONVECTION FIRING ALONG AND NORTH OF FRONT IN BAROCLINIC ZONE. BY 00Z/WED...GEM AND GFS HAS PUSHED WMFNT INTO NRN WI WHILE ECMWF HAS FRONT STILL SUPPRESSED TO THE SOUTH. BEST CHANCE FOR MORE WIDESPREAD CONVECTION ALONG AND AHEAD OF NORTHWARD MOVING WMFNT DURING THIS PERIOD...HENCE HIGHEST CHANCE POPS MONDAY NIGHT INTO TUESDAY. NEARBY CONVECTION VCNTY OF WMFNT COULD AFFECT PORTIONS OF SRN WI LATER PERIODS...ESPECIALLY AT NIGHT...AS CAPPING INVERSION SHOULD PREVENT MOST DAYTIME ACTIVITY. MORE SUMMER-LIKE TEMPS AND HUMIDITY SHOULD SETTLE IN DURING THIS PERIOD AS WELL. LATER SHIFTS MAY BE NUDING MAX TEMPS FURTHER INTO THE 80S. THREAT FOR STRONGER CONVECTION LATE NEXT WEEK INTO THE FIRST DAYS OF JUNE AS UPPER LEVEL TROUGH MOVES NORTHEAST THROUGH THE REGION. AVIATION /00Z TAFS/...VFR CONDITIONS ARE EXPECTED TONIGHT AND SATURDAY ACROSS TAF SITES. ANY PRECIPITATION SHOULD REMAIN SOUTHWEST OF THE AREA THROUGH THIS PERIOD...AS HIGH PRESSURE SLOWLY SHIFTS TO THE EAST. SHOULD SEE BROKEN TO OVERCAST MID LEVEL CLOUDS SHIFT SOUTHEAST INTO THE AREA LATER TONIGHT AND LINGER INTO SATURDAY. NORTHEAST WINDS AT THE EASTERN TAF SITES LATE THIS AFTERNOON WILL WEAKEN AND SHIFT SOUTHEAST TONIGHT INTO SATURDAY. LIGHT WINDS WILL BECOME SOUTHEAST TONIGHT AND SATURDAY AT MADISON. MARINE... SMALL CRAFT ADVISORY FOR HIGH WAVES ACROSS THE SOUTHERN TWO NEARSHORE MARINE ZONES HAS BEEN CANCELLED. NORTHEAST WINDS WILL CONTINUE TO SLOWLY DIMINISH LATE THIS AFTERNOON INTO THE EVENING...AS HIGH PRESSURE SLOWLY MOVES EAST. THIS HAS ALLOWED ANY REMAINING HIGH WAVES TO SUBSIDE TO UNDER 4 FEET. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...REM TONIGHT/SATURDAY AND AVIATION/MARINE...WOOD SATURDAY NIGHT THROUGH FRIDAY...MBK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
715 PM CDT FRI MAY 24 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SATURDAY ISSUED AT 248 PM CDT FRI MAY 24 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE STRETCHING FROM HUDSON BAY TO LAKE MICHIGAN TO THE CENTRAL GULF COAST. A FEW STRANDS OF CIRRUS IS INVADING NW WISCONSIN EARLY THIS AFTERNOON...BUT OTHERWISE...CLEAR AND COOL CONDITIONS ARE PREVAILING. LOOKING UPSTREAM...STRENGTHENING RETURN FLOW OVER THE PLAINS IS CREATING A BAND OF SHOWERS AND THUNDERSTORMS OVER EASTERN NORTH AND SOUTH DAKOTA. AS THIS WARM FRONT SHIFTS EAST TONIGHT...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...A JET STREAK...BETWEEN A SE DIVING SHORTWAVE OVER THE EASTERN GREAT LAKES AND A MID-LEVEL RIDGE OVER THE GREAT PLAINS...WILL SLIDE SOUTHEAST ACROSS THE REGION. RIGHT REAR QUAD OF THIS JET STREAK WILL SHIFT OVER NORTH-CENTRAL AND NORTHEAST WISCONSIN AFTER MIDNIGHT. DESPITE VERY DRY AIR IN THE LOW LEVELS...MODELS SPIT OUT A COUPLE BANDS OF PRECIP AS A RESULT OF MID-LEVEL CONVERGENCE/FGEN AND UPPER DIVERGENCE...THOUGH DIFFER IN THEIR PLACEMENT. THE LARGEST BAND WILL BE TIED TO THE PRIMARY BAROCLINIC ZONE OFF TO OUR WEST AND SOUTHWEST...WHICH THE NAM/GFS HAVE TRENDED A BIT TO THE WEST. HOWEVER...THE 12Z MESOMODELS CONTINUE TO PUSH THIS BAND OF PRECIP OVER CENTRAL WISCONSIN BETWEEN 06Z AND 12Z. DO NOT HAVE A GOOD FEEL WHERE THIS BAND WILL END UP. BUT LIGHT LOW LEVEL SE WINDS WILL SUPPLY A STEADY DIET OF DRY AIR...SO PRECIP WILL HAVE TO FALL OUT OF A MID-DECK...AND GIVEN THE WEAK FORCING...CANNOT SEE MUCH MORE THAN SPRINKLES LIKE THE PREVIOUS FORECASTER MENTIONED. GIVEN THE LOW IMPACT AND TO MATCH UP WITH OFFICES TO THE WEST AND NORTH...WILL KEEP THE MENTION OF SPRINKLES OVER CENTRAL WISCONSIN. A LOWERING CLOUD DECK WILL KEEP TEMPS WARMER THAN LAST NIGHT AND WILL GO WITH MID 30S NORTH TO MID 40S SOUTH. PATCHY FROST WILL REMAIN POSSIBLE OVER FAR NORTHERN WISCONSIN. SATURDAY...RIGHT REAR QUAD WILL SLIDE TO THE SOUTH-CENTRAL GREAT LAKES DURING THE MORNING. ANY SPRINKLE ACTIVITY SHOULD BE ENDING EARLY SO IT DOES NOT SEEM WORTH MENTIONING IN THE FORECAST. THE DEPARTING MID-LEVEL CONVERGENCE SHOULD ALLOW DRY AIR TO RETURN TO NORTHEAST WISCONSIN LATE MORNING ONWARD WHEN SHOULD SEE DECREASING CLOUDS. CLOUDS TO HANG LONGER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN...CLOSER TO THE PRIMARY BAROCLINIC ZONE. WITH THE ADDITIONAL CLOUD COVER...TEMPS TO REMAIN NEAR OR SLIGHTLY COOLER THAN TODAYS READINGS...AND WILL RANGE FROM THE UPPER 50S OVER CENTRAL WISCONSIN TO THE MIDDLE 60S OVER NORTHEAST WISCONSIN. .LONG TERM...SATURDAY NIGHT THROUGH FRIDAY ISSUED AT 248 PM CDT FRI MAY 24 2013 GOOD AGREEMENT BETWEEN GUIDANCE IN BIG PICTURE WITH STRENGTHENING RIDGE IN THE EAST WHILE TROF PERSISTS OVER THE WEST. PLEASANT WEATHER IS EXPECTED THROUGH MUCH OF THIS MEMORIAL DAY WEEKEND. AT THE SURFACE DRY HIGH PRESSURE TO THE EAST WILL MAINTAIN EAST TO SOUTHEAST FLOW OVER THE REGION. SOME MODEL DISCONNECT WITH HOW HANDLE SHORT WAVE ACTIVITY EXITING WESTERN TROF INTO THE PLAINS AND WESTERN LAKES LATE THIS HOLIDAY PERIOD. HAVE STAYED TOWARD DRIER EC/GFS...WITH IDEA THAT HIGH WILL KEEP PCPN TO OUR SOUTHWEST SUN AND MON. NAM APPEARS THE OUTLIER...TOO STRONG AND FAST. LIGHT WINDS AND DRY CONDITIONS TO LEAD TO ANOTHER COOL NIGHT FOR NORTHEAST WI...WITH PATCHY FROST OVER PARTS OF FAR NORTHEAST WI. TROF DEEPENS WEST BEGINNING OF NEXT WEEK PUMPING UP RIDGE JUST TO OUR EAST. THIS TO LEAD TO WARMER TEMPS AND INCREASING HUMIDITY AND INSTABILITY AS WARM FRONT LIFTS NORTH TOWARDS...OR THROUGH STATE. AGAIN SOME DISPARITY ON HOW FAR NORTH FRONT WILL GO...WITH EC LINGERING IT OVER NORTHERN WI. COULD BE LOOKING A PERIOD OF ACTIVE WEATHER NEXT WED/THU WITH POSSIBILITY OF PERIODS OF HEAVY RAINFALL AS PW`S INCREASE TO 1.5. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 715 PM CDT FRI MAY 24 2013 VFR CONDITIONS EXPECTED TONIGHT AND SATURDAY WITH MIDDLE AND HIGH CLOUDS AT TIMES. IT IS NOT OUT OF THE QUESTION TO SEE VIRGA OR A LIGHT RAIN SHOWER OVER NORTH CENTRAL AND CENTRAL WISCONSIN. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TE AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
646 PM CDT FRI MAY 24 2013 .UPDATE...THIS EVENING ISSUED AT 646 PM CDT FRI MAY 24 2013 QUICK UPDATE TO REFLECT THE FASTER TIMING OF PRECIPITATION CURRENTLY ACROSS WESTERN/CENTRAL MINNESOTA. THIS ACTIVITY IS RIDING ALONG MID LEVEL FRONTOGENESIS AND WARM AIR ADVECTION...AND COMBINED WITH SOME DECENT UPPER LEVEL FORCING / PV ADVECTION. MOST OF THE MESO-MODELS AND 18Z GUIDANCE SHOWS THIS SLIDING SOUTH/EAST MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER THROUGH THE OVERNIGHT. SO HAVE SPED UP PRECIPITATION WORDING TO ACCOUNT FOR THIS. OTHERWISE...FORECAST REMAINS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 334 PM CDT FRI MAY 24 2013 AT 3 PM...A 1003 MB HIGH PRESSURE SYSTEM...CENTERED OVER LAKE MICHIGAN...KEPT SKIES PARTLY SUNNY ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MEANWHILE FURTHER WEST...A SHORT WAVE WAS PRODUCING SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN QUARTER OF THE DAKOTAS AND WESTERN MINNESOTA. THE MESO AND DETERMINISTIC MODELS ARE CONTINUING TO STRUGGLE WITH THE EASTWARD PROGRESS OF THIS PRECIPITATION TONIGHT. THE ECMWF AND HRRR MOVE THIS PRECIPITATION ACROSS MOST OF FORECAST AREA BY 25.06Z. MEANWHILE THE NMM...ARW...GFS...GEM...RAP... AND NAM MAINLY CONFINE THE PRECIPITATION WEST OF THE MISSISSIPPI RIVER THIS EVENING...AND THEN MOVES IT ACROSS THE REMAINDER OF THE AREA OVERNIGHT. SINCE THE CONVECTION ACROSS THE DAKOTAS WILL BE MOVING INTO AN AREA WITH LESS FRONTOGENETIC FORCING...MOISTURE TRANSPORT...WEAK ISENTROPIC LIFT...AND DRIER AIR...DECIDED TO TREND THE FORECAST TOWARD THE LATTER MODEL SET. IN ADDITION...THE RADAR ECHOS ACROSS WESTERN MINNESOTA ARE SHOWING A DECREASING TREND. EVEN BY DOING THIS...THERE IS SOME VARIATIONS AMONGST THEM...SO TRIED TO GO WITH AN ENSEMBLE APPROACH WHEN ASSIGNING THE HOURLY PRECIPITATION CHANCES. THE HIGHEST PRECIPITATION CHANCE AND AMOUNTS /UP TO A HALF INCH/ WILL BE FOUND ACROSS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. ON SATURDAY...THE SHORT WAVE WILL MOVE EAST SOUTHEAST ACROSS IOWA. AS THIS OCCURS...THE 850 MB MOISTURE TRANSPORT AND ISENTROPIC LIFT WILL GRADUALLY WEAKEN. AS A RESULT...WENT WITH A DECREASING TREND IN THE PRECIPITATION TRENDS FROM LATE MORNING INTO THE AFTERNOON. ADDITIONAL RAINFALL AMOUNTS WILL BE LESS THAN 2 TENTHS OF AN INCH. WITH THE 24.12Z AND 24.18Z MODELS IN GOOD AGREEMENT THAT THERE WILL BE LESS THAN 100 J/KG CAPES...JUST KEPT AN ISOLATED THUNDERSTORM CHANCE MAINLY WEST AND SOUTH IF THE INTERSTATE 94 CORRIDOR. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 334 PM CDT FRI MAY 24 2013 FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE WARM FRONT WILL REMAIN WELL SOUTHWEST OF THE FORECAST AREA. AS A RESULT... SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN WILL REMAIN CLOUDY WITH PERIODIC SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM. OVER THE PAST 3 DAYS...THE CONSALL HAS CONTINUED TO TREND TOWARD COOLER HIGH TEMPERATURES FOR SUNDAY. IT NOW HAS HIGH TEMPERATURES AROUND 60. MEANWHILE THE ECMWF ONLY HAS HIGH TEMPERATURES IN THE LOWER 50S FOR THESE AREAS. SINCE THE ECMWF TYPICALLY VERIFIES THE BEST FOR THIS TIME PERIOD...WENT WITH A BLEND OF THE CONSALL...CONSALLBC...AND ECMWF. FROM MEMORIAL DAY INTO TUESDAY...THE MODELS ARE CONTINUING TO SHOW THAT A WARM FRONT WILL MOVE NORTHWARD INTO THE AREA. THIS WILL ALLOW ML CAPES TO CLIMB INTO THE 1K TO 3K J/KG RANGE. AS A RESULT...EXPECT THE THUNDERSTORM CHANCES TO INCREASE DURING THIS TIME PERIOD. THE 0-3KM SHEAR WOULD BE FAVORABLE FOR THE POSSIBILITY THAT A FEW THUNDERSTORMS MAY BE CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. FROM TUESDAY NIGHT INTO FRIDAY...THE MODELS CONTINUE TO STRUGGLE ON WHERE THE WARM SECTOR WILL BE LOCATED. THIS GREATLY AFFECTS THE WHERE THE PRECIPITATION MAY BE LOCATED. IN ADDITION...IT WILL ALSO AFFECT THE SHEAR AND INSTABILITY...THUS...THERE IS A LOT OF UNCERTAINTY ON WHETHER THERE WILL BE ANY SEVERE WEATHER. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 646 PM CDT FRI MAY 24 2013 RAIN SHOWERS AND ISOLATED THUNDERSTORMS WORKING EAST ACROSS CENTRAL MINNESOTA...WITH SCATTERED SPRINKLES OUT AHEAD OF THE MAIN BAND. THIS WILL IMPACT KRST BY 01Z...AND 03Z KLSE. INSTABILITY IS VERY LIMITED AND DROPS OFF VERY QUICKLY ACROSS THE AREA...SO THUNDER CHANCES ARE VERY LOW. THE RAIN IS FALLING OUT OF 10 KFT BASES MOSTLY...AND THESE VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE OVERNIGHT. AS THE ATMOSPHERE MOISTENS AND SATURATES...A LOWERING TO MVFR IS POSSIBLE AT KRST BY 14Z SATURDAY. AT KLSE...ONLY LOW-END VFR CEILINGS ARE EXPECTED. VISIBILITIES SHOULD REMAIN VFR...EVEN IN THE RAIN SHOWERS. MOST OF THE FORECAST MODELS SHOW THE BACK-EDGE OF RAIN SHOWERS CROSSING THE AREA BETWEEN 15 AND 18Z SATURDAY...SO HAVE INTRODUCED THAT TREND. CEILINGS WILL HANG ON THROUGHOUT THE REMAINDER OF THE PERIOD HOWEVER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...ZT SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...ZT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1133 PM CDT WED MAY 22 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 902 PM CDT WED MAY 22 2013 SLOW MOVING AREA OF LIGHT RAIN ASSOCIATED WITH PESKY MID-LEVEL CIRCULATION AND ASSOCIATED DEFORMATION SLOWLY WANING AND BECOMING INCREASINGLY DISORGANIZED AS NORTHERLY FLOW AND SUBSIDENCE INCREASES UPSTREAM. GOING SHORT-TERM FORECAST STILL LOOKING ON TRACK. LAST FEW RUNS OF THE HRRR SEEM TO HAVE A DECENT HANDLE ON THE DEMISE OF THIS SYSTEM WITH PRECIPITATION ENDING FROM NORTHWEST TO SOUTHEAST OVERNIGHT. EXPECT BACK EDGE OF WEAKENING PRECIPITATION SHIELD TO MOVE SOUTHEAST OF THE FORECAST AREA BY AROUND 10Z OR 11Z FOLLOWED BY CLEARING SKIES AFTER 15Z THURSDAY. EXPECT NORTHEAST WINDS TO INCREASE OVERNIGHT WITH A FEW GUSTS OF 25 TO 30 MPH MAINLY OVER THE FOX VALLEY FROM GREEN BAY SOUTH TO OSHKOSH. && .SYNOPSIS... ISSUED AT 233 PM CDT WED MAY 22 2013 UPPER LEVEL SYSTEM THAT HAS BEEN SITTING OVER THE NORTHERN PLAINS THE PAST FEW DAYS WAS FINALLY MOVING EAST...WITH THE SFC LOW PRESSURE SLIDING THROUGH SOUTHERN WISCONSIN THIS AFTERNOON PER MSAS ANALYSIS. THIS SFC LOW...COMBINED WITH ENERGY FROM A POTENT SHORTWAVE THAT WAS SWINGING AROUND THE SOUTHEAST SIDE OF THE UPPER LEVEL TROUGH INTO THE GREAT LAKES AREA...RESULTED IN WIDESPREAD SHOWERS THIS AFTERNOON. SOME LIGHTNING WAS ALSO DETECTED IN THIS AREA OF PRECIP...MAINLY IN THE VICINITY OF A NOSE OF MINOR MU-CAPES AND THE BEST FORCING. SHOWERS HAVE BECOME MORE NUMEROUS THROUGH THE MORNING AND AFTERNOON AS A DECENT 300MB JET STREAK MOVED OVER THE STATE...WITH NORTHEAST WISCONSIN SITTING IN THE RIGHT REAR QUAD. EVEN THOUGH SFC WINDS WERE OUT OF THE EAST TO NORTHEAST...THIS MORNINGS 12Z SOUNDING OUT OF GRB AND DVN SHOWED SOUTHWEST FLOW ALOFT...WHICH HELPED CONTINUE TO PUMP MOISTURE INTO SOUTHERN PORTIONS OF THE CWA. PRECIPITABLE WATER VALUES IN THIS AREA INCREASED THROUGH THE MORNING AND OCCASIONAL MODERATE TO HEAVY RAIN WAS REPORTED IN SOME LOCATIONS JUST SOUTH OF OSHKOSH AND FDL. FURTHER NORTH...SKIES REMAINED CLOUDY BUT NO PRECIP WAS REPORTED. EXPECT SHOWERS AND ISOLATED THUNDERSTORMS TO CONTINUE TO PUSH NORTH AND OVERSPREAD THE AREA THROUGH THE REST OF THE AFTERNOON...WITH PORTIONS OF EASTERN AND CENTRAL WISCONSIN SEEING OCCASIONAL MODERATE TO HEAVY RAINFALL AS THE BEST FORCING MOVES THROUGH THE STATE WITH THE MAIN UPPER LEVEL TROUGH. && .SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 233 PM CDT WED MAY 22 2013 MAIN FORECAST CONCERN WILL BE PRECIPITATION TRENDS TONIGHT AND EARLY THURSDAY MORNING. OTHERWISE...SKIES WILL CLEAR FROM NORTHWEST TO SOUTHEAST AS HIGH PRESSURE MOVES IN FROM CANADA ON THURSDAY. PRECIPITATION SHOULD OVERSPREAD THE ENTIRE AREA LATE THIS AFTERNOON...REACHING THE UPPER PENINSULA BORDER BY 21Z-00Z. GENERALLY SHOWERY CONDITIONS WILL PERSIST THROUGH THE EARLY OVERNIGHT HOURS FOR THE CWA...WITH SOME MODERATE RAIN POSSIBLE IN EASTERN WISCONSIN. THERE HAS BEEN A CONSISTENT SIGNAL FROM THE MODELS FOR STRONG FORCING 21Z TODAY THROUGH 03Z TONIGHT IN CENTRAL AND EAST CENTRAL WISCONSIN...AND EXPECT THIS TIME FRAME TO BE WHEN WE WILL SEE THE HEAVIEST AND MOST WIDESPREAD RAINFALL. BUMPED UP QPF A LITTLE IN EASTERN WISCONSIN FROM 00Z TO 06Z THURSDAY TO ACCOUNT FOR POSSIBLE HEAVIER SHOWERS WITH THIS FORCING. CONTINUED TO KEEP ISOLATED THUNDER IN THE FCST UNTIL 03Z THURSDAY AS WELL...AT WHICH POINT ANY LINGERING MU-CAPE OVER 500 J/KG WILL DISSIPATE AND THE BEST FORCING WILL MOVE AWAY FROM WISCONSIN...SO PRECIPITATION WILL BE MAINLY SHOWERS. DRY AIR WILL RUSH IN BEHIND THE UPPER LEVEL SYSTEM LATE TONIGHT AND SHOULD QUICKLY USHER OUT PRECIPITATION. THIS COMBINED WITH STRONG SUBSIDENCE WILL RESULT IN SHOWERS ENDING IN FAR NW PORTIONS OF THE CWA AROUND MIDNIGHT. THIS TREND WILL CONTINUE FROM NORTHWEST TO SOUTHEAST THROUGH THE EARLY MORNING HOURS BEFORE THE LAST OF THE PRECIP EXITS THE LAKESHORE AROUND 15Z THURSDAY. SPED UP THE EXIT OF PRECIP/CLOUDS A BIT FROM THE PREVIOUS FORECAST DUE TO MODEL TRENDS...OTHERWISE MADE FEW CHANGES TO WHAT WE HAD GOING BEFORE. TEMPERATURES WILL BE CHILLY ON THURSDAY AS STRONG COLD AIR ADVECTION ALOFT SETS UP AND GUSTY NORTH WINDS DEVELOP. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 233 PM CDT WED MAY 22 2013 MAIN FCST CONCERNS INCLUDE FROST/FREEZE POTENTIAL ON THURSDAY NIGHT... WHETHER OR NOT TO INCLUDE PCPN CHANCES FOR THE HOLIDAY WEEKEND...AND TEMPERATURES THROUGHOUT THE PERIOD. HUDSON BAY HIGH PRESSURE WILL RESIDE OVER THE REGION FOR THE END OF THE WORK WEEK...AND THROUGH THE HOLIDAY WEEKEND. A VERY DRY AIR MASS WILL BE IN PLACE THURSDAY NIGHT...WITH PRECIPITABLE WATER VALUES DROPPING TO 0.25 TO 0.33 INCH. CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPERATURES TO PLUMMET TO BLO FREEZING ACROSS MOST OF NC/FAR NE WI... WITH READINGS POSSIBLY APPROACHING 20 DEGREES IN THE TYPICAL COLD SPOTS. WILL ISSUE A FREEZE WATCH FOR NC/FAR NE WI...WHERE FREEZING TEMPS ARE LIKELY. AN SPS WILL BE ISSUED FOR THE REST OF THE CWA...WHERE PATCHY/ AREAS OF FROST ARE A GOOD BET. WILL NEED TO WATCH CENTRAL WI CLOSELY...AS FCST MIN TEMPS ARE CLOSE TO FREEZING. THE LARGE HIGH PRESSURE WILL ONLY DRIFT SLIGHTLY TO THE EAST OVER THE HOLIDAY WEEKEND...WITH THE RIDGE AXIS SETTING UP JUST TO OUR EAST. THE ECMWF HAS BEEN CONSISTENT IN KEEPING ANY PCPN TO OUR WEST AND SOUTH THROUGH THE WEEKEND...WHILE THE GFS/GEFS ATTEMPT TO BRING SOME LGT QPF INTO OUR SW COUNTIES BY ABOUT SUNDAY. HAVE KEPT THE FCST DRY THROUGH SUNDAY...AND ONLY MENTIONED A SLIGHT CHANCE OF SHOWERS FROM SUNDAY NIGHT INTO TUESDAY. TEMPERATURES WILL REMAIN A LITTLE BLO NORMAL THROUGH THE WEEKEND...WITH HIGHS IN THE 60S. A WARM FRONT IS EXPECTED TO LIFT NORTH INTO THE REGION TUESDAY NIGHT AND WEDNESDAY...AND MAY BRING A CHANCE OF THUNDERSTORMS AND MILDER TEMPS TO THE FORECAST AREA. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1130 PM CDT WED MAY 22 2013 A RAPIDLY IMPROVEMENT IN FLIGHT CONDITIONS WILL SWEEP NW-SE ACRS THE AREA LATE TNGT AND THU MORNING AS THE RAIN-PRODUCING CYCLONE DEPARTS THE AREA TO THE E AND IS REPLACED BY CANADIAN HIGH PRESSURE. .MARINE... ISSUED AT 233 PM CDT WED MAY 22 2013 HIGH-END SMALL CRAFT ADVISORY ISSUED FOR THIS AFTERNOON THROUGH AT LEAST FRIDAY FOR GUSTY NORTH TO NORTHEAST WINDS. GUSTS WILL GET CLOSE TO GALE FORCE TOMORROW LATE MORNING AND EARLY AFTERNOON... HOWEVER THE BEST MIXING WILL OCCUR AFTER THE STRONGER WINDS OFF THE SFC BEGIN TO DISSIPATE. SO WILL KEEP THE STRONG WORDED SMALL CRAFT ADVISORY WITH JUST A MENTION OF A FEW GALE FORCE GUSTS POSSIBLE. PERSISTENT MARINE FOG HAS BEGUN TO LIFT AND VISIBILITIES ARE COMING UP THIS AFTERNOON AS WINDS INCREASE. KEPT PATCHY FOG IN THE FORECAST UNTIL 03Z THURSDAY...BUT AT THIS POINT DEW POINT DEPRESSIONS AND WINDS INCREASE AND FOG SHOULD NO LONGER BE AN ISSUE. WILL REMOVE FOG MENTION FROM THE MWW. && .GRB WATCHES/WARNINGS/ADVISORIES... FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR WIZ005-010>013-018-019-021. && $$ UPDATE.........ESB SYNOPSIS.......WOLF SHORT TERM.....WOLF LONG TERM......KIECKBUSCH AVIATION.......JS MARINE.........WOLF
AREA FORECAST DISCUSSION
NWS GRAY ME
1235 AM EDT SAT MAY 25 2013 .SYNOPSIS... A COLD FRONT WILL PUSH OFFSHORE AND STALL THIS EVENING. LOW PRESSURE WILL DEVELOP ON THE FRONT NEAR CAPE COD AND WILL SLOWLY DRIFT NORTH THROUGH THE GULF OF MAINE SATURDAY AND SATURDAY NIGHT. LOW PRESSURE WILL ACCELERATE NORTH INTO LABRADOR ON SUNDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST SUNDAY NIGHT THROUGH MONDAY. HIGH PRESSURE WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY AND WILL PUSH EAST OF THE REGION WEDNESDAY NIGHT. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... UPDATE...A QUICK UPDATE TO KEEP FCST UP TO DATE WITH CURRENT OBSERVATIONS. COLD AIR RUSHING IN ON A NORTHERLY FLOW. PRECIP WILL LIKELY CHANGE TO A MIX IN THE HIGHER TERRAIN SAT. PREV UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS...WITH THE COLD FRONT NOW HAVING SLIPPED SOUTH OF THE COAST WATERS AS OF 0230Z. LOW PRESSURE WILL CONTINUE TO TAKE SHAPE OFF THE NEW ENG COASTLINE THEREAFTER...WITH CYCLOGENESIS OCCURRING NEAR CAPE COD THIS EVENING. LATEST HRRR MODEL PICKING UP WELL ON CONVECTIVE SEGMENTS CROSSING THE FORECAST AREA AT THIS TIME. THIS MODEL DEPICTS MORE AREAS OF RAIN MOVING THROUGH THE REGION LATE TONIGHT AND SATURDAY MORNING. WILL CONTINUE TO MONITOR COLD AIR RUSHING INTO THE MTNS FROM CANADA OVERNIGHT. THERE COULD BE SOME MIXED SNOW AND RAIN OVER THE HIGHER TERRAIN FOR THIS STORM WHICH IS VERY SIMILAR TO THE MAY 26TH 1967 EVENT. HAVE ADJUSTED WINDS AND TEMPS FOR THE HIGHER TERRAIN. WINDS WILL BECOME RATHER GUSTY FOR ANY HIKERS OUT OF THE NORTH AND NORTH OVER THE NEXT COUPLE OF DAYS...WITH SOME SNOW ACROSS THE HIGH TERRAIN. PREV DISC... COLD FRONT CURRENTLY MOVING EAST THROUGH EASTERN NEW HAMPSHIRE AND NORTHWEST MAINE AND THIS BOUNDARY WILL CONTINUE TO PUSH OFF TO THE EAST THROUGH THE REMAINDER OF THE AFTERNOON. FRONT WILL STALL OFFSHORE THIS EVENING AND WILL BE THE FOCUS OF LIGHT TO MODERATE RAINFALL IN MID COAST AND CENTRAL MAINE DURING THE REMAINDER OF THE AFTERNOON INTO THIS EVENING. WILL SEE A BRIEF BREAK IN THE ACTION ACROSS NEW HAMPSHIRE DURING THE REST OF THE AFTERNOON BEFORE NEXT BATCH OF PRECIP EDGES IN FROM THE WEST. WILL TAKE SOME TIME FOR LOW PRESSURE TO GET SPUN UP OVERNIGHT SO THIS BREAK MAY TRANSLATE EASTWARD INTO WESTERN MAINE FOR THE EVENING HOURS BEFORE 850 OVER-RUNNING GETS GOING IN EARNEST ACROSS WESTERN MAINE AFTER MIDNIGHT. 12Z MODELS TRENDING FARTHER WEST WITH AXIS OF HEAVIEST PRECIP AND COMING INTO LINE WITH LAST NIGHT 00Z ECMWF. 24 HOUR QPF FOR THE MOUNTAINS AND CONNECTICUT VALLEY DOWN TO AROUND AN INCH TO 1.5 INCHES THROUGH 00Z SUN. WITH THIS IN MIND...DOESN`T APPEAR FLOODING WILL BE AN ISSUE CONSIDERING THE BREAK IN THE ACTION THIS AFTERNOON AND LONG DURATION OF THE EVENT ITSELF...SO HOLDING OFF ON ANY WATCHES AT THIS POINT IN TIME. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SUNDAY/... RAIN WILL CONTINUE SATURDAY THROUGH SATURDAY NIGHT AS SURFACE LOW BECOMES TRAPPED UNDER UPPER LEVEL SYSTEM AND MEANDERS AROUND THE GULF OF MAINE THROUGH SUNDAY MORNING. MAY SEE SOME WET SNOW OVER THE HIGHEST TERRAIN AT SOME POINT ON SATURDAY IN FAR WESTERN ZONES BUT ENOUGH WARM AIR WRAPS AROUND THE SYSTEM THAT THIS WOULD BE FAIRLY BRIEF. BETTER CHANCE FOR THIS WOULD BE IN THE GREENS OF VERMONT AND THE DACKS. WILL BE A COLD AND BLUSTERY DAY WITH TEMPS HOLDING IN THE 40S IN MOST AREAS AND SHOWING LITTLE CHANGE SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... UPR LVL AND SFC LOWS LIFTING NE ON SUNDAY WITH STEADIER PRCP BECOMING MORE SCT IN NATURE AND LIGHTER IN INTENSITY. ANY LEFTOVER SHRA ENDING SUNDAY NGT AS THE SYSTEM MOVES INTO THE MARITIMES. MEMORIAL DAY LOOKS LIKE FAIR WX NOW WITH SYSTEM PULLING OUT FAR ENOUGH TO THE NE. STILL SOME CYCLONIC FLOW ALOFT AND SOME LEFTOVER MOISTURE THAT COULD PRODUCE SOME CLOUDINESS ESPECIALLY IN THE N/MT ZONES DUE TO UPSLOPING NW SFC WINDS. MIGHT SEE AN ISOLD SHRA IN THE N/MT ZONES OTRW NO PRCP EXPECTED ON MEMORIAL DAY. HIGH PRES AND UPR LVL RIDGE BUILD IN FOR TUESDAY INTO WEDNESDAY. THE UPR LVL RIDGE HOLDS 0N OVER THE ERN U.S. BUT A SERIES OF WEAK UPR LVL SHORT WAVE TROFS DRIVE THRU THE RIDGE FOR LATE WEDNESDAY AND THURSDAY. THIS FORMS A WRM FRONTAL BOUNDARY TO OUR S THAT LIFTS N AND WILL PROVIDE SOME CLOUDINESS AND ISOLD TO SCT SHRA FROM LATE WEDNESDAY THRU THURSDAY. THE UPR LVL RIDGE BECOMES BETTER ESTABLISHED OVER THE E COAST THURSDAY NGT AND FRIDAY AS THE SHORT WAVES EXIT THE COAST. THIS SHOULD ALLOW WRM AIR TO CONT MOVING IN FROM THE SW. STILL CAN`T RULE OUT PSBL SHRA DUE TO WRM FNT MOVING THRU. GENERALLY USED BLEND OF GFS40/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5 THEN GFS40, GMOS, HPC QPF, MEX MOS AND WNA4 FOR THE REST OF THE LONG TERM FCST. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM...IFR/LIFR CEILINGS TONIGHT THROUGH SATURDAY NIGHT. LONG TERM /SUNDAY THROUGH WEDNESDAY/...MVFR TO PSBL IFR IN SHRA THAT WILL BE TAPERING OFF SUNDAY INTO SUNDAY NGT. MAINLY VFR MONDAY THRU TUESDAY AND MOST OF WEDNESDAY. && .MARINE... SHORT TERM...HAVE EXTENDED SCA TO GO RIGHT THROUGH SATURDAY. ALTHOUGH WINDS DROP OFF AT SOME POINT...WAVES WILL REMAIN AT LEAST IN THE 3 TO 5 FOOT RANGE...WITH GREATER SEAS OUT OVER THE OPEN WATERS. COASTAL FLOOD ADVISORY FOR MINOR SPLASH-OVER AROUND THE TIME OF HIGH TIDE. LONG TERM /SUNDAY THROUGH WEDNESDAY/...SCA WIND GUSTS AND SEAS PSBL SUNDAY THRU MOST OF SUNDAY NGT THEN HIGH PRES DROPS CONDITIONS BELOW SCA LEVELS MONDAY THRU WEDNESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ150>154. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE... FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
325 AM EDT SAT MAY 25 2013 .SHORT TERM...TODAY AND TONIGHT EARLY MORNING MSAS ANALYSIS IS SHOWING A SURFACE RIDGE EXTENDING SOUTHWARD THROUGH THE LAKE SUPERIOR/MICHIGAN/HURON BASINS. THE BEST SURFACE RIDGING COMPONENT INSIDE OF THE CWA IS ACROSS THE NORTHERN THUMB DOWN INTO PORT HURON. PERUSING THROUGH THE SURFACE OBSERVATIONS...FEELING IS THE BEST POTENTIAL FOR ANY FROST FORMATION WILL BE IN THE THUMB AND LOW LYING AREAS OF THE GLACIAL TERRAIN WITH THE LOCAL OFFICE TEMPERATURE AT 33 DEGREES AS OF 230 AM LDT. WILL MAINTAIN THE FROST ADVISORY AS IS FOR SIMPLICITY. THERE HAS BEEN A DECENT RADAR PRESENTATION OVERNIGHT ACROSS PORTIONS OF MN/WI/IA TIED TO THE AGEOSTROPHIC RESPONSE OF MERGING AND SHEARING OF SHORTWAVE ENERGY. ONE HR PRECIPITATION AMOUNTS HAVE BEEN LESSENING AS THE PRECIPITATION/VIRGA PUSHES FARTHER TO THE SOUTHEAST. THIS IS LIKELY IN RESPONSE TO INCREASING CONFLUENCE ALOFT AS THE ENTRANCE REGION LIES DIRECTLY OVER LOWER MICHIGAN. THE BEST UPPER LEVEL FORCING IN THE FORM OF 700-500MB FRONTOGENESIS WILL BRUSH FAR SOUTHWESTERN SECTIONS OF THE STATE BETWEEN 12-15Z...BEFORE PASSING HARMLESSLY TO THE SOUTH. THE AMOUNT OF AMBIENT DRY AIR IN THE LOWEST 12 KFT AGL SUPPORTS VIRTUALLY NO PRECIPITATION POTENTIAL TODAY. THE PREFERENCE REGARDING HIGH CLOUD PROG LIES WITH THE 25.05Z RUC WHICH BRINGS HIGH CLOUDS INTO THE SOUTHWESTERN 2/3RDS OF THE CWA BETWEEN 9-16Z THIS MORNING. INCREASED INSOLATION WITH SOME MODERATION OF THE AIRMASS WILL SUPPORT A SOLID 3-8F DEGREE UPTICK IN HIGH TEMPERATURES. EXPECT READINGS TO RANGE FROM THE MIDDLE 50S IN THE FAR NORTHERN THUMB/LAKE HURON SHORELINE TO THE MIDDLE 60S DETROIT SOUTHWARD. SURFACE HIGH PRESSURE WILL EXPAND ACROSS THE CENTRAL GREAT LAKES TONIGHT...BRINGING THE PROSPECTS OF ANOTHER COOL TO COLD NIGHT. DIFFERENTIAL AIRMASS RECOVERY SHOULD BE GOOD FOR A FEW DEGREES OFF THIS MORNINGS MINS. WORKED WITH A BLEND OF UNDERCUT GUIDANCE WITH SOME PERSISTENCE. EXPECTED LOWS TONIGHT SHOULD RANGE FROM THE LOWER TO MIDDLE 30S IN THE THUMB TO LOWER 40S SOUTHEAST OF THE TERRAIN. && .LONG TERM...SUNDAY THROUGH FRIDAY LOWER MICHIGAN WILL RESIDE BETWEEN A HIGH AMPLITUDE RIDGE ACROSS THE UPPER MIDWEST AND A DEEP UPPER LOW LIFTING FROM NEW ENGLAND INTO THE CANADIAN MARITIMES DURING THE LATER HALF OF THE WEEKEND...SUSTAINING A CONFLUENT FLOW ALOFT. AT THE SFC...THIS WILL TRANSLATE TO HIGH PRESSURE BUILDING FROM THE UPPER GREAT LAKES ON SUNDAY TO THE EASTERN GREAT LAKES ON MONDAY. OTHER THAN THE POTENTIAL FOR SOME HIGH CLOUDS...SKIES SHOULD REMAIN MAINLY CLEAR WITH VERY DRY AIR OVERHEAD. TEMPS WILL SLOWLY MODERATE...LEADING TO AN OVERALL WARMING TREND HEADING INTO MEMORIAL DAY. EXPECT MIXING DEPTHS MAY OVERACHIEVE WITH PLENTY OF SUNSHINE AND SUBSTANTIAL LOW LEVEL DRY AIR. THIS SUPPORTS LEANING TOWARD THE HIGHER END OF GUIDANCE MAX TEMPS /MID TO UPPER 60S SUNDAY AND AROUND 70 MONDAY/. THE DRY AIRMASS AND WEAK SFC GRADIENT WILL SUPPORT OPTIMAL RADIATIONAL COOLING POTENTIAL...SO MINS SUN NIGHT WILL CONTINUE TO BE QUITE COLD FOR LATE MAY /UPPER 30S TO MID 40S/. THE MID LEVEL RIDGE IS FORECAST TO BREAK DOWN EARLY NEXT WEAK AS NUMEROUS SHORT WAVE IMPULSES ARE EJECTED OUT OF THE LONG WAVE TROUGH OVER THE WRN US AND ACROSS THE CNTRL/NRN PLAINS. THE BULK OF THE 00Z MODEL SUITE SUGGEST MCS DEVELOPMENT ACROSS THE UPPER MIDWEST OR WRN GREAT LAKES MON AFTERNOON/NIGHT AS LOW LEVEL INFLOW STRENGTHENS. THE POTENTIAL FOR REMNANT MCS ACTIVITY TO ADVANCE INTO SE MI REMAINS HIGHLY UNCERTAIN AT THIS TIME. WHILE SEVERAL MODEL SOLUTIONS ARE QUITE BULLISH WITH QPF OVER SE MI MON NIGHT AND TUES...THERE IS LIKELY SOME SEMBLANCE OF CONVECTIVE FEEDBACK IN THE MODELS. THERE IS ALSO CONCERN THAT THE MODELS HAVE A POOR HANDLING OF MCS PROPAGATION...WHICH COULD LEAD TO REMNANT CONVECTION BEING MUCH FARTHER SOUTH. THUS PLAN TO CARRY VERY LOW CHANCE POPS TUESDAY. PERSISTENT LOW LEVEL S-SWLY FLOW SHOULD HOWEVER LIFT A WARMER AND MORE HUMID AIRMASS INTO SRN LOWER MI BY MID WEEK...MARKED BY THE PASSAGE OF A SFC WARM FRONT. THIS WILL JUSTIFY A CHANCE OF SHOWERS/THUNDERSTORMS LATE TUES THROUGH WED. THE ECMWF REMAINS STEADFAST IN DEVELOPING A MORE AMPLIFIED UPPER TROUGH OVER THE WRN US BY MIDWEEK AS ENERGY EJECTS OUT OF THE GULF OF ALASKA AND INTO THE WEST COAST. A SEASONALLY STRONG UPPER JET WITHIN THE BASE OF THE DEEP GULF OF ALASKA UPPER LOW AND CURRENT AMPLIFIED NATURE OF THE FLOW LENDS SUPPORT TO THE ECMWF. THIS SOLUTION BUILDS THE SUBTROPICAL RIDGE FARTHER NORTH INTO THE ERN US LATE IN THE WEEK AND SUGGESTS SE MI MAY BE CAPPED. EVEN THE LESS AMPLIFIED GFS BUILDS MID LEVEL HEIGHTS SUBSTANTIALLY ACROSS SE MI. THUS THE FORECAST FOR THE LATER HALF OF NEXT WEEK WILL HAVE VERY LOW POPS WITH MAX TEMPS WELL INTO THE 80S. && .MARINE... A STABLE ANTICYCLONE WILL EXPAND ACROSS THE GREAT LAKES THROUGH THE HOLIDAY WEEKEND. THIS WEATHER FEATURE WILL BE RESPONSIBLE FOR MORE TYPICAL MARINE CONDITIONS FOR LATE MAY. WAVE HEIGHTS ARE ONLY EXPECTED TO RANGE IN THE 1 TO 2 FOOT RANGE IN MANY AREAS THROUGHOUT THE WEEKEND. && .AVIATION...ISSUED 1148 PM EDT FRI MAY 24 2013 //DISCUSSION... HIGH PRESSURE WILL DOMINATE THE TAF PERIOD WITH NOTHING MORE THAN MID/HIGH CLOUDS SPREADING ACROSS SOUTHEAST MICHIGAN OVERNIGHT. HIGH PRESSURE WILL ALSO MAINTAIN A LIGHT NORTHEAST GRADIENT WELL INTO SATURDAY NIGHT. SCATTERED COVERAGE OF DIURNAL CU AROUND 5-6KFT IS LIKELY DURING PEAK HEATING ON SATURDAY. //DTW THRESHOLD THREATS... * NONE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060- MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082- MIZ083...UNTIL 8 AM SATURDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CB LONG TERM....SC MARINE.......CB AVIATION.....JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
344 AM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 344 AM CDT SAT MAY 25 2013 INITIAL SHIELD OF WAA SHOWERS THAT WAS DEPICTED WELL ON 310K ISENTROPIC SFC ON THE NAM/GFS IS FADING AWAY ACROSS WRN WI AS THIS BATCH OF FORCING WEAKENS AND DIVES SOUTHEAST. IN ITS WAKE...WE HAVE WAA AT H85...BUT THE DEEPER MOISTURE HAS PUSHED EAST...SO PRECIP HAS CUT OFF PRETTY QUICK. WITH THE WAA AND WEAK MOISTURE TRANSPORT...SHOULD BE ABLE TO GET SOME LIGHT SHOWERS/SPRINKLES ACROSS MN THIS MORNING...BUT NOT MUCH MORE THAN THAT. BEST CHANCE FOR RAIN TODAY WILL BE ACROSS SRN MN. WARM FRONT NOW CAN BE FOUND ACROSS SOUTH CENTRAL NEB INTO NE KAN...WITH A STRONG LLJ OVERRUNNING IT. THIS HAS GENERATED AN MCS OVER ERN NEB THIS MORNING. THUNDER STARTING TO INCREASE ACROSS IA AS WELL AS THE LLJ HAS SLOWLY WORKED EAST. MOST OF THIS THUNDERSTORM ACTIVITY WILL REMAIN SOUTH OF MN THROUGH THE DAY...BUT ALL HI-RES MODELS SHOW SOME OF THIS MOISTURE FROM IA SNEAKING UP INTO SOUTH CENTRAL MN THROUGH MORNING...WHERE SOME HIGH CHANCE/LIKELY POPS ARE CONTINUED THROUGH THE MORNING HOURS. FOR THE AFTERNOON...PRECIP LOOKS TO SHUT OFF...BUT WE WILL BE STUCK WITH FAIRLY BROAD CLOUD COVER...WITH THE ONLY HOPE FOR SOME BREAKS ACROSS THE NE MPX CWA THANKS TO THE INFLUENCE OF A DRY SFC HIGH THAT WILL BE SPLAYED OUT ACROSS THE GREAT LAKES. GIVEN THE CLOUD COVER WILL BE A COOL DAY...WITH TEMPERATURES IN SOUTH CENTRAL MN LIKELY STAYING IN THE 50S THANKS TO BETTER RAIN CHANCES AND THICKER CLOUD COVER. FOR TONIGHT...ALL MODELS SHOW ANOTHER ROUND OF CONVECTION RIDING ALONG NORTH OF THE WARM FRONT...KIND OF LIKE WHAT WE HAVE SEEN OVERNIGHT TO OUR SOUTHWEST. QUESTION BECOMES HOW FAR NORTH DOES THE ACTIVITY MAKE IT. CONSENSUS PLACEMENT FROM THE WARM FRONT PLACES IT BY 12Z SUNDAY MORNING FROM THE BLACK HILLS...DOWN THROUGH YANKTON...SD AND THEN DOWN TO THE CENTRAL IA/MO BORDER. ONCE AGAIN...WILL SEE A LLJ OVERRUNNING THIS FRONTAL FEATURE...WHICH SHOULD GENERATE YET ANOTHER MCS. GIVEN THE FRONTS PLACEMENT TO OUR SOUTHWEST...BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE SOUTH OF THE UPPER MN RIVER IN SW MN INTO SC MN. FOR TIMING...FAVORED HIGHEST POPS TO AFTER 6Z...AS CONVECTION SHOULD FIRE THIS EVENING OVER SE SODAK INTO NE NEB...THEN HEAD TOWARD SW/SC MN. ALL OF THIS ACTIVITY WOULD BE ELEVATED...SO SEVERE THREAT LOOKS MINIMAL...WITH THE MAIN IMPACT BEING THE POTENTIAL FOR HEAVY RAIN...AS WE HAVE SEEN THIS EVENING IN NEB. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 344 AM CDT SAT MAY 25 2013 THE LONG TERM PERIOD CONTINUES TO LOOK INCREASINGLY WET AND STORMY. THIS IS DUE TO THE REGION BEING SANDWICHED BETWEEN A BUILDING UPPER HIGH ALONG THE EASTERN SEABOARD... WHILE A VERY DEEP TROUGH PUSHES INTO THE WESTERN HALF OF THE UNITED STATES. THERE SHOULD BE A ROUND OF CONVECTION PASS ACROSS SOUTHERN MN SUNDAY MORNING...VERY SIMILAR TO WHAT HAS BEEN ONGOING OVERNIGHT ACROSS NE/IA. THE STORMS TO OUR SOUTH CURRENTLY HAVE BEEN BASICALLY SUB SEVERE... BUT VERY EFFICIENT RAIN PRODUCERS... WITH UPWARDS OF 1.75 INCHES OF RAIN IN THREE HOURS. THIS IS THE TREND EXPECTED SUNDAY MORNING ACROSS SOUTHERN MN... ESPECIALLY THE I-90 CORRIDOR. THEREAFTER... A SIGNIFICANT DIMINISHING TREND IN THE PRECIPITATION FOR SUNDAY AFTERNOON AND EVENING WITH THE NMM/ARW WRF/S IN AGREEMENT. MEMORIAL DAY IS LOOKING A LITTLE WORSE NOW WITH EVEN THE ECMWF DRIVING A WAVE OF CONVECTION ACROSS THE FA DURING THE DAY AND EVENING. JUST GENERAL THUNDER INDICATED ON SWODY2 WHICH SEEMS REASONABLE WITH THE MAIN WARM FRONTAL BOUNDARY MEANDERING FROM THE CENTRAL PLAINS TO THE LOWER OHIO VALLEY. AGAIN... THE CONCERN WILL BE LOCALIZED HEAVY RAINFALL. THE DETERMINISTIC RUNS WOULD ALSO SUGGEST ANOTHER ROUND OF CONVECTION FOR US LATE MONDAY NIGHT AND TUESDAY MORNING... ESPECIALLY ACROSS SOUTHERN MN. THIS REPEATING ROUNDS OF POTENTIAL CONVECTION IS DISTURBING WITH AREAS OF SOUTHERN AND ESPECIALLY SOUTHEAST MN RUNNING WELL ABOVE NORMAL ON RAINFALL FOR THE MONTH OF MAY. THE THREAT FOR FLASH FLOODING WILL BE ON THE INCREASE. IT WAS POINTED OUT ON FRIDAY IN THE WEATHERTALK FROM DR SEELY AT THE UMN THAT SINCE MARCH 1ST...(METEOROLOGICAL SPRING) IT HAS BEEN ONE OF THE WETTEST IN HISTORY FOR MANY AREAS OF MN. ADD THIS TO THE CIPS ANALOGS FOR 5 DAYS FROM NOW AND ONE SEES A VERY WET PATTERN ACROSS ALL OF THE REGION WITH 2 INCHES OF RAINFALL EXCEEDING 30 PERCENT PROBABILITY WITH EVEN WIDESPREAD 3 INCHES HAVING A 10 PERCENT PROBABILITY. THIS IS IN ADDITION TO THE RAINS SUNDAY THROUGH TUESDAY. NOT SURPRISING THEN ARE THE RUN TOTALS FROM THE GFS AND ECMWF THROUGH NEXT FRIDAY WHICH PAINT THE LANDSCAPE WITH 2 TO 4 INCHES OF RAIN... WITH 4 INCHES OR MORE SOUTH OF US. DIGRESSING FOR A MOMENT... ONE OF THE MONTHS/YEARS THAT HAS SHOWN UP IN THE CIPS ANALOGS RECENTLY IS JULY 1993... WITH RECORD FLOODING IN THIS PART OF THE COUNTRY. A REVIEW FROM NCDC SHOWED LOW PRESSURE ALOFT OVER THE WESTERN HIGH PLAINS WITH A STRONG SW JET AT 250 MB ACROSS OUR AREA. THE BERMUDA HIGH HAD PUSHED INTO THE SOUTHEAST UNITED STATES WITH ORGANIZED 850 MB WINDS FROM THE WESTERN GULF OF MEXICO TO THE WESTERN GREAT LAKES. HENCE... THE FLOODING POTENTIAL IS A BIG CONCERN FOR THE WEEK AHEAD AS THE PATTERN IN THE SUMMER OF 1993 MIMICS OUR WEEK AHEAD QUITE WELL. FINALLY... AND JUST AS IMPORTANT... WILL BE THE THREAT FOR SEVERE WEATHER NEXT WEEK AS THE WARM FRONT LIFTS NORTH INTO OUR AREA BEGINNING ON TUESDAY. NOT TOO CONCERN ABOUT SEVERE ON SUNDAY. THE CHANCE INCREASES SOME ON MONDAY (ISOLATED)...ESPECIALLY IF AFTERNOON CONVECTION DEVELOPS AS DEEP LAYER SHEAR RISES. THEN FROM TUESDAY ONWARD THERE IS SEVERE POTENTIAL EACH DAY. THE CIPS ANALOGS CONTAIN MANY SEVERE REPORTS FOR US FOR THE MIDDLE OF NEXT WEEK WITH SEVERE PROBABILITIES FROM 15 TO 30 PERCENT FOR THE ENTIRE FA USING THE TOP 8 ANALOGS. A COLD FRONT MAY MOVE ACROSS THE FA FROM FRIDAY INTO SATURDAY...DIMINISHING THE SEVERE WEATHER THREAT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1259 AM CDT SAT MAY 25 2013 BATCH OF WARM ADVECTIVE SHOWERS WORKING INTO WI TO START THE TAF...BUT DRY AIR IS STARTING TO TAKE ITS TOLL...WITH PRECIP COVERAGE BEGINNING TO DIMINISH. LLJ STARTING TO ORGANIZE INTO ERN NEB AT THE MOMENT...AND WILL LAY INTO IOWA OVERNIGHT. FOLLOWED IDEA OF HRRR AND OTHER HI-RES MODELS WITH SHOWERS CURRENTLY OVER THE MN/WI BORDER SLOWLY DIMINISHING THROUGH 10Z...WITH ANY SIGNIFICANT TSRA ACTIVITY STAYING SOUTH OF MN THE REST OF THE NIGHT. HOWEVER...WILL HAVE PLENTY OF CLOUD COVER AND WEAK MOISTURE TRANSPORT REMAINING INTO THE MORNING...WITH BOUTS OF SPRINKLES/LIGHT RAIN EXPECTED ACROSS MN...SO DID KEEP SOME VCSH MENTION GOING. OTHER CHANGE TO THESE TAFS WAS TO START SLOWING DOWN ARRIVAL OF MVFR CIGS LATER TODAY. BASED TIMING ON THE RAP/HRRR/NAM...WHICH SHOW MVFR CIGS CURRENTLY DEVELOPING OVER SE NEB NOT ARRIVING INTO THE RWF AREA UNTIL CLOSE TO 18Z. WITH WARM FRONT EXPECTED TO STAY DOWN ALONG THE IA/MO BORDER TODAY...EXPECT MAJORITY OF MVFR CIGS TO STAY DOWN IN IOWA THROUGH THE DAY...WITH A MORE SIGNIFICANT PUSH OF MVFR CIGS NORTH NOT EXPECTED UNTIL TONIGHT AS THE FRONT BEGINS A SLOW CRAWL NORTH ACROSS IOWA...BRINGING MVFR CIGS FURTHER NORTH AS WELL. AS RESULT...DELAYED ARRIVAL OF MVFR CIGS UNTIL AFTER 00Z FOR ALL MN TERMINALS EXCEPT RWF. KMSP...GIVEN HOW CIGS WITH RAIN ONLY DROPPED TO 6K FT AT BEST...FEEL CONFIDENT IN VFR CIGS REMAIN THROUGH THE COURSE OF THE DAY TODAY. SHOWER COVERAGE WILL BE DIMINISHING THROUGH 8Z...WITH NOT MUCH MORE THAN SPRINKLES EXPECTED THE REST OF THIS TAF PERIOD...AS LLJ FORCING REMAINS WELL SOUTH/WEST OF THE FIELD. HAVE MODERATE CONFIDENCE IN MVFR CIGS DEVELOPING SAT NIGHT...BUT WITH THE WARM FRONT ONLY MAKING IT INTO CENTRAL IA...MSP MAY REMAIN NE OF THE MAIN MVFR CIG SHIELD THROUGH THE 30 HRS OF THE TAF. /OUTLOOK FOR KMSP/ SUN...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS. MON...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10 KTS. TUE...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SSE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
327 AM CDT SAT MAY 25 2013 .SHORT TERM...TODAY THROUGH SUNDAY... AXIS OF WEAK WARM ADVECTION AND FRONTOGENESIS MAXED OUT IN THE 700-600MB LAYER CONTINUES TO TRANSLATE SLOWLY EASTWARD ACROSS EASTERN MINNESOTA EARLY THIS MORNING WHILE SLOWLY WEAKENING. NW-SE ORIENTED BAND OF SHOWERS HAS SLOWLY DIMINISHED IN BOTH COVERAGE AND INTENSITY OVER THE PAST COUPLE OF HOURS..AND SHOULD CONTINUE TO DO SO THROUGH MID MORNING TODAY. HOWEVER..UNTIL LOW-MID LEVEL FLOW BACKS AS IT STARTS TO FEEL THE INFLUENCE OF THE NEXT WAVE MOVING FROM THE ROCKIES INTO THE NRN PLAINS THERE WILL BE AT LEAST SOME MODEST FORCING FOR ASCENT..AND A FEW SHOWERS COULD PERSIST INTO LATE MORNING. BY THIS AFTERNOON..MAIN THREAT FOR ADDITIONAL SHOWERS/TSTORMS IS EXPECTED TO CONSOLIDATE TO AREAS MOSTLY SOUTH AND WEST OF THE DULUTH CWA IN CLOSER PROXIMITY TO LOW LEVEL BAROCLINIC ZONE FROM THE DAKOTAS INTO THE MID MISSOURI VALLEY. AS A RESULT..WE HAVE CONTINUED THE PREVIOUS TREND OF A DRY FORECAST FOR THIS AFTERNOON IN MOST AREAS AS EAST/SOUTHEAST LOW LEVEL FLOW BRINGS A FLUX OF DRIER AIR INTO THE REGION. THE FAR SOUTHWEST CWA WILL REMAIN CLOSE ENOUGH TO THE LOW LEVEL THERMAL/MOISTURE GRADIENT TO WARRANT AT LEAST A MENTION OF A FEW SHOWERS TONIGHT. CHANCES FOR SHOWERS THEN EXPAND A BIT FARTHER EASTWARD ON SUNDAY AS NEXT WAVE BRUSHES NORTHEASTWARD..ALONG WITH SOME CONTRIBUTION FROM ENHANCED WARM/MOIST ADVECTION BY THE LLJ LATE SAT NIGHT AND SUNDAY MORNING. EASTERLY BOUNDARY LAYER FLOW WILL ALSO KEEP AREAS NEAR LAKE SUPERIOR COOLER TODAY AND SUNDAY..ALONG WITH LOCALLY GUSTY WINDS IN SOME OF THE FAVORED LOCATIONS NEAR THE TWIN PORTS AND ASHLAND. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY NIGHT... A PERIOD OF ACTIVE WEATHER WILL DEVELOP THIS WEEK WITH MULTIPLE DISTURBANCES MOVING ACROSS THE UPPER MIDWEST...PRODUCING RAIN SHOWERS AND THUNDERSTORMS MONDAY THROUGH SATURDAY. UPPER LEVEL RIDGE AXIS ACROSS THE REGION LATE THIS WEEKEND WILL SHIFT EWD ON MONDAY AS A 500MB S/W PUSHES INTO THE RIDGE ACROSS THE NRN PLAINS ON THE LEADING EDGE OF A LONG WAVE TROUGH OVER THE WRN CONUS. THIS S/W IS EXPECTED TO HAVE AN ASSOCIATED SFC INVERTED TROUGH/WARM FRONT LIFT NWD THROUGH CNTRL MN ON MONDAY. RAIN SHOWER CHANCES WILL INCREASE DURING THE DAY MONDAY...ALONG WITH A SLIGHT CHC OF T-STORMS. A LLJ WILL DEVELOP MON NIGHT/TUE MORNING AND USHER IN A MOIST UNSTABLE AIR MASS ACROSS THE REGION. THE INTERACTION OF THIS S/W AND INCREASED INSTABILITY/MOISTURE WILL ALLOW FOR THE POTENTIAL OF MDT/HVY RAIN SHOWERS AND EVEN A FEW STRONG STORMS THROUGH TUE MORNING. THE ACTIVE PATTERN CONTINUES THROUGH THE MIDDLE AND LATTER PART OF THE WEEK AS THE LONG WAVE TROUGH OVER THE WEST TRANSITIONS EASTWARD AND CONTINUES TO DRAW UP A ROBUST AMT OF WARM MOIST AIR FROM THE SOUTH AND PRODUCES RAIN SHOWERS AND SCATTERED T-STORMS ACROSS THE NORTHLAND INTO THE EARLY PART OF THE WEEKEND. THERE ARE NOTABLE DIFFERENCES IN THE SYNOPTIC PATTERNS OF THE ECMWF AND GFS DURING THIS WEEK...WHICH LEAD TO UNRESOLVABLE CONVECTIVE MODES. AT THIS TIME...WILL CONTINUE WITH HIGH CHC POPS...LOW LIKELY POPS. IT WILL BE DIFFICULT TO NAIL DOWN SPECIFIC TIMES/LOCATIONS OF THE BEST/HEAVIEST PRECIP AND ANY T-STORM CHANCES UNTIL WELL INTO THE WEEK. TEMPERATURES WILL CONTINUE ON THE WARMING TREND THROUGH THE WEEK WITH HIGHS ON MONDAY IN THE 60S...AND OVERNIGHT LOWS IN THE 40S. BY WEDNESDAY...HIGHS WILL BE TOPPING OUT IN THE 70S AND LOWER 80S...WITH NIGHT TIME LOWS IN THE 50S AND 60S. && .AVIATION...06Z TAF ISSUANCE... VFR CONDITIONS PREVAILED ACROSS THE NORTHLAND LATE THIS EVENING. AN AREA OF SHOWERS STRETCHED FROM NORTHWEST MINNESOTA INTO SOUTHEAST MINNESOTA. AN AREA OF MID LEVEL FGEN WAS HELPING TO DRIVE THESE SHOWERS...AND THIS MOVES EAST THEN DIMINISHES OVERNIGHT. MVFR CONDITIONS WILL BE POSSIBLE IN THE HEAVIER SHOWERS...BUT THE OVERALL CHANCE OF THAT IS LOW AND MOST LIKELY TOWARD KBRD. AN AREA OF MVFR CEILINGS EXISTS OVER PORTIONS OF CENTRAL NEBRASKA LATE THIS EVENING...AND THE RAP SHOWS THOSE MOVING QUICKLY NORTH INTO SOUTHWEST MINNESOTA TONIGHT BUT DOES NOT BRING THEM INTO KBRD ON SATURDAY. WE`LL HAVE TO MONITOR THE PROGRESSION OF THESE CLOUDS...AS WE WENT VFR FOR PREVAILING CONDITIONS AT KBRD THROUGH THE PERIOD. && .POINT TEMPS/POPS... DLH 57 42 60 45 / 20 10 10 10 INL 64 44 68 47 / 10 10 10 20 BRD 61 46 62 50 / 40 20 30 40 HYR 63 42 67 47 / 20 10 10 20 ASX 60 40 61 43 / 10 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...MILLER LONG TERM....TENTINGER AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
100 AM CDT SAT MAY 25 2013 .UPDATE... 06Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 355 PM CDT FRI MAY 24 2013 SURFACE CYCLONE AND ASSOCIATED TROUGH NOTED ON IR SATELLITE IMAGERY FROM SOUTHERN ALBERTA INTO EASTERN WYOMING. WARM FRONT ASSOCIATED WITH THIS SYSTEM CURRENTLY FIRING UP SHIELD OF MAINLY LIGHT SHOWERS AND ISOLATED THUNDERSTORMS OVER FAR EASTERN SODAK AND WESTERN QUARTER OF OUR CWA. USED A COMBO OF HRRR...GFS40 305K SFC...AND THETA E ADVECTION TO PAINT PICTURE OF FORWARD PROGRESSION ACROSS REMAINDER OF CWA DURING THE OVERNIGHT. FAIRLY DRY COLUMN TO CONTEND WITH OVER MUCH OF THE FA THIS AFTERNOON AND EVENING...THUS AM EXPECTING MAINLY LIGHT PCPN FOR THIS FIRST WAVE OF ACTIVITY. ALTHOUGH K INDICES AND 850 LI`S INDICATING LITTLE CHANCE OF THUNDER ATTM...DECIDED TO INCLUDE ISOLATED CHANCE MOST AREAS INTO TOMORROW AFTN DUE TO FAIR AMOUNT OF LIGHTNING NOTED ON CURRENT 0.5 REFLECTIVITY. AS PREVIOUSLY ADVERTISED CHANCES FOR WIDESPREAD CONVECTIVE ACTIVITY DECREASE MARKEDLY AFTER ABOUT 25/15Z TIME FRAME...AS WARM FRONTAL BOUNDARY STALLS OVER NE MINNESOTA BY LATE SATURDAY MORNING. DECIDED TO INCREASE SATURDAY`S HIGHS BY ONE CATEGORY CONSIDERING LIMITED PCPN POTENTIAL AND POSSIBILITY OF MUCH LESS CLOUD COVER THEN CURRENTLY FORECAST. FOCUS FOR ANY CONVECTIVE ACTIVITY ON SATURDAY AFTERNOON DEFINITELY NOTED OVER FAR SOUTHERN MINNESOTA...WITH BEST UPPER LEVEL SUPPORT VIA 250MB WEAK TO MODERATE DIVERGENCE OVER THIS REGION. LEFT SLGT POPS OVER REMAINDER OF CWA TOMORROW AFTN DUE TO FAIRLY ROBUST 850-500MB LAPSE RATES. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 355 PM CDT FRI MAY 24 2013 THETA E ADVECTION BLOSSOMS FROM SOUTHWEST INTO CENTRAL MN ON SATURDAY NIGHT INTO SUNDAY...WHEN BOTH GFS AND NAM MODELS FORECAST A SHORTWAVE TO CARVE THROUGH THE MID LEVEL RIDGE. EXPECT TO SEE SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING...WITH THE HIGHEST COVERAGE OVER SOUTHWEST MN WHERE 850 MB MOISTURE TRANSPORT IS SLIGHTLY ENHANCED. HIGH TEMPERATURES ON SUNDAY WILL LIKELY MAX OUT IN THE UPPER 50S AND LOWER 60S...AS THE WARM FRONT REMAINS TO THE SOUTH OF THE AREA AND EXTENSIVE CLOUD COVER AND SHOWERS PERSIST. YET MORE WEAK SHORTWAVES RIDE NORTH OF THE WARM FRONT ON MEMORIAL DAY...AND CONTINUE THE POSSIBILITY OF SCATTERED SHOWERS AND THUNDERSTORMS. SHOULD SEE TEMPS MODERATE SLIGHTLY FOR THE HOLIDAY...ALTHOUGH IT WILL STILL BE ON THE COOL SIDE WITH UPPER 60S TO MID 70S. ON TUESDAY...THE AFOREMENTIONED WARM FRONT WILL BEGIN TO LIFT NORTH...AND ENTER THE FORECAST AREA FROM WEDNESDAY THROUGH THURSDAY. THIS WILL SIGNAL THE ARRIVAL OF SLIGHTLY WARMER TEMPERATURES AND AN INCREASE IN HUMIDITY...WITH HIGHS IN THE 75 TO 80 DEGREE RANGE. THE ARRIVAL OF THE FRONT WILL ALSO YIELD AN INCREASING THREAT FOR SEVERE WEATHER AND EXCESSIVE RAINFALL FOR THURSDAY AND FRIDAY. FORECAST PRECIPITABLE WATER VALUES INCREASE TO OVER 1.5 INCHES...WHICH ILLUSTRATES THE POTENTIAL FOR A DOUSING RAINFALL EVENT. THE SEVERE WEATHER POTENTIAL IS SOMEWHAT UNCERTAIN DUE TO THE DIFFERENCES IN THE MODELS WITH THE EVOLUTION OF THE WESTERN TROUGH...AND THE DEGREE OF SURFACE CYCLOGENESIS THAT ENSUES OVER THE NORTHERN PLAINS TOWARD THE END OF NEXT WEEK. HOWEVER...IF THE 24.12Z GFS SHEAR AND INSTABILITY PROGS WERE TO PAN OUT...THERE WOULD BE A FAIRLY HIGH THREAT FOR SEVERE WEATHER AND TORNADOES ACROSS CENTRAL AND SOUTHERN MN ON THURSDAY AFTERNOON/EVE. WILL CONTINUE TO MONITOR AND REFINE OVER THE NEXT FEW MODEL RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1259 AM CDT SAT MAY 25 2013 BATCH OF WARM ADVECTIVE SHOWERS WORKING INTO WI TO START THE TAF...BUT DRY AIR IS STARTING TO TAKE ITS TOLL...WITH PRECIP COVERAGE BEGINNING TO DIMINISH. LLJ STARTING TO ORGANIZE INTO ERN NEB AT THE MOMENT...AND WILL LAY INTO IOWA OVERNIGHT. FOLLOWED IDEA OF HRRR AND OTHER HI-RES MODELS WITH SHOWERS CURRENTLY OVER THE MN/WI BORDER SLOWLY DIMINISHING THROUGH 10Z...WITH ANY SIGNIFICANT TSRA ACTIVITY STAYING SOUTH OF MN THE REST OF THE NIGHT. HOWEVER...WILL HAVE PLENTY OF CLOUD COVER AND WEAK MOISTURE TRANSPORT REMAINING INTO THE MORNING...WITH BOUTS OF SPRINKLES/LIGHT RAIN EXPECTED ACROSS MN...SO DID KEEP SOME VCSH MENTION GOING. OTHER CHANGE TO THESE TAFS WAS TO START SLOWING DOWN ARRIVAL OF MVFR CIGS LATER TODAY. BASED TIMING ON THE RAP/HRRR/NAM...WHICH SHOW MVFR CIGS CURRENTLY DEVELOPING OVER SE NEB NOT ARRIVING INTO THE RWF AREA UNTIL CLOSE TO 18Z. WITH WARM FRONT EXPECTED TO STAY DOWN ALONG THE IA/MO BORDER TODAY...EXPECT MAJORITY OF MVFR CIGS TO STAY DOWN IN IOWA THROUGH THE DAY...WITH A MORE SIGNIFICANT PUSH OF MVFR CIGS NORTH NOT EXPECTED UNTIL TONIGHT AS THE FRONT BEGINS A SLOW CRAWL NORTH ACROSS IOWA...BRINGING MVFR CIGS FURTHER NORTH AS WELL. AS RESULT...DELAYED ARRIVAL OF MVFR CIGS UNTIL AFTER 00Z FOR ALL MN TERMINALS EXCEPT RWF. KMSP...GIVEN HOW CIGS WITH RAIN ONLY DROPPED TO 6K FT AT BEST...FEEL CONFIDENT IN VFR CIGS REMAIN THROUGH THE COURSE OF THE DAY TODAY. SHOWER COVERAGE WILL BE DIMINISHING THROUGH 8Z...WITH NOT MUCH MORE THAN SPRINKLES EXPECTED THE REST OF THIS TAF PERIOD...AS LLJ FORCING REMAINS WELL SOUTH/WEST OF THE FIELD. HAVE MODERATE CONFIDENCE IN MVFR CIGS DEVELOPING SAT NIGHT...BUT WITH THE WARM FRONT ONLY MAKING IT INTO CENTRAL IA...MSP MAY REMAIN NE OF THE MAIN MVFR CIG SHIELD THROUGH THE 30 HRS OF THE TAF. /OUTLOOK FOR KMSP/ SUN...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS. MON...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10 KTS. TUE...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SSE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...AJZ LONG TERM...LS AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1237 AM CDT SAT MAY 25 2013 .AVIATION...06Z TAFS VFR CONDITIONS PREVAILED ACROSS THE NORTHLAND LATE THIS EVENING. AN AREA OF SHOWERS STRETCHED FROM NORTHWEST MINNESOTA INTO SOUTHEAST MINNESOTA. AN AREA OF MID LEVEL FGEN WAS HELPING TO DRIVE THESE SHOWERS...AND THIS MOVES EAST THEN DIMINISHES OVERNIGHT. MVFR CONDITIONS WILL BE POSSIBLE IN THE HEAVIER SHOWERS...BUT THE OVERALL CHANCE OF THAT IS LOW AND MOST LIKELY TOWARD KBRD. AN AREA OF MVFR CEILINGS EXISTS OVER PORTIONS OF CENTRAL NEBRASKA LATE THIS EVENING...AND THE RAP SHOWS THOSE MOVING QUICKLY NORTH INTO SOUTHWEST MINNESOTA TONIGHT BUT DOES NOT BRING THEM INTO KBRD ON SATURDAY. WE`LL HAVE TO MONITOR THE PROGRESSION OF THESE CLOUDS...AS WE WENT VFR FOR PREVAILING CONDITIONS AT KBRD THROUGH THE PERIOD. && .PREV DISCUSSION... /ISSUED 646 PM CDT FRI MAY 24 2013/ UPDATE... AREA RADARS SHOW AN AREA OF RAIN...WITH A FEW THUNDERSTORMS...FROM FAR NORTHWEST MINNESOTA INTO SOUTH CENTRAL MINNESOTA AS OF EARLY EVENING. THIS IS TIED CLOSELY WITH AN AREA OF 700MB FGEN. THE FGEN WILL MOVE A BIT TO THE EAST TONIGHT...THEN DIMINISH BY 12Z. WE WILL UPDATE IN A BIT TO ADJUST POPS AND WE`LL USE THE 700MB FGEN AS A GUIDE TO WHERE TO PUT THE HIGHER POPS. AVIATION...00Z TAFS VFR CONDITIONS COVERED THE NORTHLAND AS OF EARLY EVENING...BUT AN AREA OF SHOWERS WERE MOVING EAST TOWARD KBRD/KXVG. WE EXPECT THIS AREA OF SHOWERS...AND POSSIBLY SOME THUNDERSTORMS...TO MOVE EAST THIS EVENING. IT SHOULD NOT OVERTAKE ALL AREAS AS DRIER AIR EXISTS OVER THE EAST...AND THE FORCING RESPONSIBLE DOES NOT MOVE THROUGH THE NORTHLAND EITHER. KBRD WILL HAVE THE BEST CHANCE AT SEEING RAIN TONIGHT. MVFR CONDITIONS WILL DEVELOP OVER PORTIONS OF THE WEST...WITH CEILINGS LOWERING OVER OTHER LOCATIONS THROUGH THE PERIOD. PREV DISCUSSION... /ISSUED 405 PM CDT FRI MAY 24 2013/ SHORT TERM...TONIGHT AND SATURDAY... AN AREA OF SHOWERS AND THUNDERSTORMS FROM THE EASTERN DAKOTAS AND WESTERN MN WILL SLOWLY SPREAD EAST THIS EVENING. THIS AREA IS AN AREA OF LOW LEVEL WARM AIR ADVECTION AND AN ASSOCIATED UPPER LEVEL VORT MAX ROUNDING OUT THE TOP OF UPPER RIDGE. MOST OF THE LIFT ASSOCIATE WITH THE SYSTEMS WILL SLIDE ACROSS THE SOUTHWEST SECTIONS OF THE CWA...WHERE THERE ARE THE HIGHER POPS. PUT SOME POPS IN FARTHER NORTH ALONG THE HIGHWAY 2 CORRIDOR IN MN AND NORTHWEST WI...BUT WITH DEW POINTS IN THE 20S...IT WILL TAKE AWHILE TO MOISTEN UP FOR RAIN. THE SHORT TERM MODELS...LOCAL AND THE SREF...ARE CONSISTENT IN SHOWING THE BAND OF SHOWERS OUT TO THE WEST WITH MORE SPOTTY SHOWERS OVER THE EAST LATE TONIGHT AND TOMORROW MORNING. BY AFTERNOON THE MAJOR AREA OF PRECIPITATION WILL MOSTLY BE ACROSS WESTERN AND SOUTHERN MINNESOTA...LEAVING MOST OF THE NORTHLAND UNDER CLOUDY SKIES. LONG TERM [SATURDAY NIGHT - THURSDAY]... HIGH PRESSURE OVER EASTERN CANADA AND THE EASTERN UNITED STATES WILL HELP TO SUPPRESS RAIN CHANCES ACROSS THE NORTHLAND SATURDAY NIGHT AND SUNDAY. THE NORTHLAND WILL BE HEADING INTO A POTENTIALLY WARM...WET...AND ACTIVE PERIOD NEXT WEEK. A MID/UPPER LEVEL RIDGE OVER THE CENTRAL UNITED STATES WILL BEGIN TO SHIFT EAST AS A MID/UPPER LEVEL TROUGH MOVES INTO THE WEST. THE MODELS INDICATE ONE OR MORE WARM FRONTS MAY MOVE THROUGH OR NEAR THE NORTHLAND DURING THE MID TO LATE WEEK PERIOD...WHICH COULD BE A STORMY PERIOD FOR THE NORTHLAND. && .POINT TEMPS/POPS... DLH 57 41 61 43 / 20 0 10 10 INL 62 43 67 45 / 20 10 0 10 BRD 58 46 63 50 / 50 10 30 30 HYR 61 41 67 47 / 30 0 10 20 ASX 60 39 63 44 / 20 0 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
428 AM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 423 AM CDT SAT MAY 25 2013 FOCUS REMAINS ON TSTM POTENTIAL. TSTMS CONTINUE EARLY THIS MORNING WITH MCS ROLLING EAST ACROSS CENTRAL/EASTERN NEBRASKA. MAIN IMPACT CURRENTLY FM CONVECTION IS HEAVY RAINFALL...WITH MANY LOCATIONS NORTH OF INTERSTATE 80 PICKING UP AT LEAST AN INCH OF RAIN. WE HAVE HAD ONE REPORT OF 3.13 INCHES SO FAR AT LOUP CITY WITH RAIN STILL FALLING. THIS INITIAL ROUND OF CONVECTION WILL CONTINUE TO MOVE EAST/END THIS MORNING THEN ATTENTION TURNS TO ADDITIONAL CHANCES FOR CONVECTION THIS AFTN. SFC BOUNDARY HAS SETTLED NEAR THE NEB/KS STATELINE AND FRONT IS PROGGED TO LIFT NORTHWARD THIS AFTN INTO SC NEB...WITH SFC LOW ORIENTED IN EASTERN COLORADO AND DRY LINE ALONG THE HIGH PLAINS REGION. FRONTAL BOUNDARY AND ANY RESIDUAL OUTFLOW BOUNDARIES WILL BE FOCUS FOR CONVECTION AGAIN THIS AFTN/EVE AND BOUNDARY PLACEMENT WILL NEED TO BE MONITORED CLOSELY. CAP LOOKS TO HOLD INITIALLY HOWEVER MODELS ARE INDICATING DEVELOPMENT ALONG THE DRY LINE AND ALONG/NORTH OF WARM FRONTAL BOUNDARY...AND HAVE FOLLOWED CLOSER TO RAP MODEL FOR POTENTIAL DEVELOPMENT THIS AFTN. STORMS FOR TODAY/TONIGHT HAVE THE POTENTIAL TO BE MORE VOLATILE WITH SEVERE PARAMETERS INDICATING POTENTIAL FOR SUPERCELLS. INSTABILITY IS PROGGED AROUND 4000 J/KG WITH SHEAR OF 40KTS OR SO AND STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS AND EVEN TORNADOES IN VCNTY OF BOUNDARIES. HEAVY RAINFALL/FLOODING ALSO REMAINS A CONCERN DUE TO THE HEAVY OVERNIGHT/EARLY THIS MORNING AND PRECIPITABLE WATER VALUES ARE ON THE ORDER OF AN INCH TO INCH AND A HALF AND ARE A 100 TO 150 PERCENT OF NORMAL. ALL OF THIS BEING SAID...MODELS ARE NOT CONSISTENT IN FRONTAL POSITION WHICH IS KEY TO DEVELOPMENT THIS AFTN. AGAIN FEEL RAP AND LATEST SREF RUN HAS A BETTER HANDLE ON THE FARTHER SOUTH WARM FRONTAL POSITION ACROSS OUR AREA TODAY...AND WILL NEED TO MONITOR CLOSELY. OTHERWISE...LOOK FOR SOME WARMER TEMPS THIS AFTN AND STEADY/GUSTY WINDS WITH THE HIGHEST WIND SPEEDS EXPECTED ACROSS NC KANSAS/SOUTH OF WARM FRONT...WHERE WINDY CONDITIONS ARE POSSIBLE WITH GUSTS OF 30+ MPH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 423 AM CDT SAT MAY 25 2013 SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MOST EVERY DAY AND TEMPERATURES THROUGH THE PERIOD. A VERY ACTIVE WEATHER PATTERN WILL AFFECT THE FORECAST AREA THROUGH THE PERIOD. AN UPPER LEVEL LOW DEVELOPS IN THE WESTERN CONUS AND GRADUALLY MOVES THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY FRIDAY. THIS UPPER LOW WILL SEND WAVES INTO THE FORECAST AREA THROUGH THE PERIOD. THE MODELS ARE SIMILAR IN THE MAIN FEATURES...BUT THE ECMWF HAS A LITTLE STRONGER AMPLITUDE MID WEEK. EACH OF THE WAVES WILL HAVE A CHANCE FOR SOME THUNDERSTORMS WHEN THEY MOVE THROUGH. IT CERTAINLY WILL NOT BE A RAIN OUT...IT WILL NOT RAIN ALL OF THE TIME...BUT THERE WILL BE CHANCES FOR SOME SHOWERS AND THUNDERSTORMS AT VARIOUS TIMES DURING THE PERIOD. THE BEST CHANCES FOR THUNDERSTORMS WILL BE SUNDAY AFTERNOON AND SUNDAY NIGHT...DURING WHICH TIME THE CAPE APPROACHES 5000 J/KG. ANOTHER GOOD CHANCE WILL BE MONDAY AFTERNOON AND MONDAY NIGHT WITH CAPES OVER 5000 J/KG AGAIN. BEYOND MONDAY THE MODELS HAVE A FEW TIMING DIFFERENCES WITH THE UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND THEREFORE TIMING THUNDERSTORMS IS MORE OF A CHALLENGE. TEMPERATURES WILL BE THE WARMEST SUNDAY THROUGH TUESDAY THEN SLOWLY COOL OFF TOWARD THE END OF THE WEEK. TEMPERATURES SHOULD STILL REMAIN ABOVE NORMAL FOR THIS TIME OF YEAR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 1217 AM CDT SAT MAY 25 2013 TSTMS WILL IMPACT THE TERMINAL INTO THE OVERNIGHT HOURS...WITH POTENTIAL FOR SEVERE WEATHER WITH DAMAGING WINDS...LARGE HAIL AND HEAVY RAINFALL. CHCS FOR TSTMS AND SEVERE WEATHER RETURN SATURDAY EVENING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY LONG TERM...JCB AVIATION...FAY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
109 AM EDT SAT MAY 25 2013 .SYNOPSIS... CHILLY HIGH PRESSURE TAKES CHARGE TONIGHT INTO SATURDAY. WARM FRONT LIFT NORTH INTO THE OHIO VALLEY AND WEST VIRGINIA EARLY TUESDAY. A WARMING TREND EXPECTED MEMORIAL DAY THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... 9 PM UPDATE. STILL GOING WITH A FROST SCENARIO FOR THE LOW LANDS UNDER A FROST ADVISORY. DEWPOINTS ACROSS THE NORTH ARE NOW IN THE LOW TO MID 30S ON A DECREASING NORTH WIND. WHILE THE MAJOR CITIES MAY ESCAPE FROST...THE OUTLYING AREAS AND FAVORED LOW SPOTS ARE INCREASINGLY LIKELY FOR SOME FROST. WILL MAKE NO CHANGE TO HEADLINES NOR CURRENT FORECAST. PREVIOUS DISCUSSION... VERY TOUGH FCST TONIGHT REGARDING FROST/FREEZE POTENTIAL. DWPTS CURRENTLY STRADDLING THE MARGINAL THRESHOLD FOR FROST TONIGHT GIVEN AFTN MIXING. NOT SURE IF THESE GO LWR NEXT FEW HRS BEFORE RECOVERING THIS EVE. GUIDANCE FOR METRO AREAS IN THE LOWLANDS RUN 32 TO 40F FROM KHTS TO KCRW. H925 WINDS STAY UP ARND 20 KTS OVERNIGHT AS SFC HIGH BUILDS IN TO ALLOW WINDS AT THE GROUND TO TRY TO GO CALM. ALL OF THIS COMPLICATES MATTERS FOR EXPANDING FROST ADV. HOWEVER...GIVEN TIME OF YEAR AND FACT THAT MOST FOLKS HAVE SOME OF THEIR VEGGIES IN THE GROUND ALONG WITH ANNUAL PLANT INVESTMENTS...FELT PRUDENT TO LEAN A LITTLE LIBERAL AND EXPAND TO ENCOMPASS REST OF CWA SAVE FOR S COAL FIELDS TO SW VA. OUTLYING AREAS WILL SEE BEST SHOT OF FROST. HEADLINE SHOULD GARNER MORE ATTENTION FOR FOLKS TO TAKE PRECAUTIONS TO BE ON SAFE SIDE. ALSO EXPANDED FRZ WARNING TO RALEIGH BASED ON GUIDANCE RANGING FROM 28F TO 33F. THEY WILL HAVE GET UNDER INVERSION THOUGH GIVEN H925 WINDS OFF MDLS OVERNIGHT. OTHER CONCERN IS STRATUS OVERNIGHT ACROSS THE N. NAM HAS BEEN WAY TOO FAST IN ERADICATING THE LLVL MOISTURE VS RUC WHICH HAS BEEN PRETTY STEADY. RUC SHOWS CLDS LIFTING AND SCT THIS EVE ACROSS THE N BEFORE REDEVELOPING IN N MTNS BY 06Z. NAM KEEPS ENTIRE COLUMN DRY BUT HAS NOT HANDLED TDY WELL AT ALL. SO WILL LEAN TOWARD RUC AND REDEVELOP SOME STRATUS IN N MTNS LATE TONIGHT. THIS MAY KEEP TEMPS UP TONIGHT ESPECIALLY IN VALLEYS...BUT STILL FEEL AOB FRZ TEMPS WILL BE REALIZED. UPR TROF AXIS SHIFTS TO E COAST ON SAT WITH SOME RECOVERY IN TEMPS COMPARED TO TDY. INHERITED TEMPS LOOKED GOOD AND ONLY NEEDED TWEAKING SOME...MAINLY ACROSS THE N. && .SHORT TERM /TONIGHT THROUGH MONDAY/... MADE MODIFICATIONS TO THE SHORT TERM FORECAST AS FOLLOWS: HIGH PRESSURE WILL BE IN CONTROL THROUGH THE WEEKEND...KEEPING DRY CONDITIONS AREAWIDE. MODELS SHOW A MID LEVEL SHORTWAVE...EVIDENT IN H5 CHARTS...UNDER NORTHWEST FLOW ALOFT...MOVING ACROSS SOUTHERN OH...SOUTHEAST INTO NORTHWEST KY. REMOVED ANY POPS FOR THE WEEKEND AS MOISTURE LOOKS VERY LIMITED OVER WV. IN FACT...THERE COULD BE SOME CLEARING SATURDAY NIGHT INTO SUNDAY MORNING...KEEPING TEMPERATURES AT OR JUST BELOW FREEZING OVER POCAHONTAS AND RANDOLPH COUNTIES. INCLUDED PATCHY FROST OVER NORTHEAST MOUNTAINS. HIGH PRESSURE MOVES EAST OVER THE MID ATLANTIC STATES KEEPING INFLUENCE OVER WV FOR A DRY SUNDAY THROUGH MONDAY NIGHT. MINOR CHANGES TO TEMPERATURES THROUGH THE PERIOD...PERHAPS A COUPLE DEGREES LOWER CLOSER TO THE COOLER MET. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ANOTHER SHORTWAVE UNDER NORTHWEST FLOW ALOFT PASSES ACROSS SOUTHEAST OH AND WV MONDAY AND TUESDAY. AT THE SAME TIME...A WARM FRONT LIFTS NORTH INTO SOUTHERN OH...ACROSS WV AND VA ORIENTED WEST TO EAST BY 12Z TUESDAY. THESE TWO FEATURES WILL BE CAPABLE TO PRODUCE SHOWERS AND STORMS LATE MONDAY INTO TUESDAY AS THE WARM FRONT MOVES NORTH OF THE AREA BY EARLY WEDNESDAY. INCREASED POPS TO CHANCE INCLUDING THUNDER IN WEATHER GRIDS ACCORDINGLY. HIGH PRESSURE TAKES CONTROL BY EARLY WEDNESDAY PROVIDING DRY WEATHER WITH A SLOW WARMING TREND THROUGH THE REST OF THE WEEK. TWEAKED COUPLE OF DEGREES DOWN FROM HPC GUIDANCE IN THE EXTENDED PERIODS. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS EXPECTED ACROSS THE FORECAST AREA THROUGH THE TAF PERIOD. ONE EXCEPTION IS SOME MVFR CEILINGS CURRENTLY IN EKN...AND COULD ALSO GET SOME MVFR VISIBILITY THERE BEFORE THE SUN COMES UP. EKN SHOULD RETURN TO VFR BY 13Z-14Z. VFR CU FIELD WILL DEVELOP TODAY...GENERALLY 6-9KFT. UPPER LEVEL DISTURBANCE BRINGS CLOUDS TO THE SOUTH TONIGHT...BUT AGAIN REMAINING VFR. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY... FORECAST CONFIDENCE...HIGH. ALTERNATE SCENARIOS: TIMING AND DENSITY OF FOG AT EKN MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 05/25/13 UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M M M M M M M M M M M PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H M M M H H H H H H H AFTER 06Z SUNDAY... NO WIDESPREAD IFR EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR WVZ005>011- 013>020-026>032-039-040. FREEZE WARNING UNTIL 8 AM EDT THIS MORNING FOR WVZ035>038-046- 047. OH...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR OHZ066-067-075- 076-083>087. KY...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR KYZ101>103-105. VA...NONE. && $$ SYNOPSIS...ARJ/30 NEAR TERM...JMV/30 SHORT TERM...ARJ LONG TERM...ARJ AVIATION...MZ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
431 AM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM CDT SAT MAY 25 2013 THUNDERSTORM COMPLEX OVER NEBRASKA OVERNIGHT CONTINUES EARLY THIS MORNING. SEEING SHOWERS AND STORMS BEGINNING TO EXPAND ACROSS NORTHWEST IOWA AS WELL AS LOW LEVEL THETAE ADVECTION INCREASES. HIGH RES MODEL SUITE LOOK TO HAVE A PRETTY GOOD HANDLE ON THIS ACTIVITY. EXPECT IT TO CONTINUE THIS MORNING AND POSSIBLY EXPAND A BIT FURTHER NORTH INTO PORTIONS OF SOUTHWEST MINNESOTA. LOWERED POPS ACROSS SOUTHEAST SOUTH DAKOTA...AS ALL INDICATIONS ARE THAT THESE STORMS WILL NOT DEVELOP NORTHWEST OF THEIR CURRENT LOCATION. MOST OF THE STORMS SHOULD BE EAST OF THE CWA BY 16Z. MAIN IMPACTS WILL BE BRIEFLY HEAVY RAIN AND POSSIBLY SMALL HAIL WITH THESE CELLS...AS EFFECTIVE SHEAR AND CAPE ARE TOO LOW FOR ANY SEVERE THREAT. MUCH OF THE AFTERNOON SHOULD THEN BE DRY ACROSS THE CWA WITH AN AREA OF SUBSIDENCE LIKELY BEHIND THIS MORNINGS SHORTWAVE. WARM FRONTAL BOUNDARY WILL POSITION ITSELF SOUTH OF THE MISSOURI RIVER THIS AFTERNOON. HRRR AND RAP TRY TO BREAK THE CAP THEIR THIS AFTERNOON...BUT BOTH THESE MODELS SEEM A BIT OVERDONE WITH DEWPOINTS AND INSTABILITY. FEEL MORE LIKELY SCENARIO IS ACTIVITY WAITS FOR THE LOW LEVEL JET TO KICK IN AFTER 0Z BEFORE IT GETS GOING. OTHER ISSUE TODAY IS CLOUD COVER AND HIGH TEMPERATURES. INTERESTINGLY THE HRRR AND RAP ARE COMPLETE OPPOSITE OF EACH OTHER...GIVING AROUND A 20 DEGREE DIFFERENCE IN HIGHS...WITH THE RAP HAVING MORE STRATUS AND COOLER TEMPERATURES. THE GEM AND ECMWF SIDE CLOSER TO THE RAP...WITH THE NAM IN BETWEEN. SINCE THE AREAL COVERAGE OF LOW STRATUS IS CURRENTLY LESS THAN EXPECTED...DID GO AHEAD AND RAISE HIGHS SEVERAL DEGREES FOR TODAY IN OUR CENTRAL AND WEST. ALSO THE HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION...SO ONE WOULD THINK ITS SHORT RANGE FORECAST SHOULD BE SOMEWHAT RELIABLE...AND IT HAS CONSISTENTLY BEEN WARM FOR TODAY. LOWERED HIGHS A FEW IN THE EAST WHERE IT IS RAINING...AND WHERE STRATUS SHOULD INDEED HOLD IN FOR MUCH OF THE DAY. AGAIN THIS IS A PRETTY LOW CONFIDENCE TEMPERATURE FORECAST FOR ANYWHERE EAST OF THE JAMES RIVER. BUT FEEL GOING FORECAST IS A DECENT STARTING POINT...WITH THE DAY SHIFT LIKELY HAVING TO ADJUST UP OR DOWN DEPENDING ON CLOUD COVER TRENDS. QUIET SHORT TERM CONDITIONS FROM THE AFTERNOON HOURS SHOULD TURN QUICKLY TO MORE STORMY CONDITIONS OVERNIGHT. GAVE A FAIR AMOUNT OF CREDIT TO THE CONSISTENCY OF THE 00Z HIGH RESOLUTION NAMDNG5 AND WRF-ARW SOLUTIONS...WHICH FIT THE OVERALL CONCEPTUAL MODEL FOR CONVECTIVE INITIATION TONIGHT. BOUNDARY FROM CURRENT NIGHT MCS WILL BE FESTERING AND DRIFTING NORTHWARD...WITH LIKELY 1000 TO 1500 J/KG ELEVATED CAPE LIFTED FROM 1 TO 1.5 KM AGL. AS 35 TO 40 KNOT LOW LEVEL JET DEVELOPS TONIGHT THROUGH THE CENTRAL PLAINS... SHOULD BECOME ENOUGH TO INITIATE ELEVATED THUNDERSTORMS NEAR/NORTH OF THE BOUNDARY WHICH WILL BE DRIFTING NORTHWARD OF INTERSTATE 80 DURING THE EVENING HOURS. EFFECTIVE SHEAR IN AREAS NORTH OF THE BOUNDARY WILL BE VERY CONCENTRATED IN THE 1-3KM LAYER WITH STRONGEST WINDS IN LOW LEVELS AND WEAKENING MID LEVEL WINDS ROUGHLY 20-30 KNOTS...WITH LESSER DEEP LAYER SHEAR CONTRIBUTIONS FROM ABOVE. ALL SUGGEST AT LEAST A MINIMAL THREAT FOR ISOLATED LARGER HAIL OR DAMAGING WINDS THROUGH THE MISSOURI RIVER CORRIDOR AND LIFTING SOMEWHAT NORTHWARD THROUGH 066-08Z. OTHER SIGNIFICANT CONVECTIVE INITIATION IS LIKELY TO OCCUR BACK THROUGH THE WESTERN HIGH PLAINS WHERE STRONGER SHEAR EXISTS WITH A BIT STRONGER MID LEVEL WINDS TO AROUND 25 KNOTS...AS WELL AS THE DEEP UPSLOPE TRANSPORT OF MOISTURE TO RESULT IN STRONGER INSTABILITY. EVENTUALLY...WHEN SUPERCELL MOTIONS WHICH WILL TAKE ACTION MORE SOUTHWARD THAN EAST START TO EASE...AND LOW LEVEL JET VEERS EASTWARD...WILL FIND A MORE LINEAR MCS LIKELY TAKING SHAPE. MANY HI RES MODELS SUGGEST THIS MCS WILL ZIPPER DOWN THE LOCATION OF THE WARM ADVECTION WING SPREADING NORTHWARD...MOVING TOWARD EAST CENTRAL SD AND SOUTHWEST MN LATE NIGHT. SEVERE THREAT WITH THIS FEATURE WOULD SEEM TO BE SOMEWHAT LOWER...BUT LIKELY TO GET SOME GUSTY WINDS AND AREAS OF HEAVY RAINFALL. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 430 AM CDT SAT MAY 25 2013 MCS EXPECTED TO WEAKEN AND SHIFT EAST ON SUNDAY...AND WITH MID LEVEL FORCING SHOWING TENDENCY TO FORCE SUBSIDENCE AROUND MIDDAY...AGAIN EXPECT THAT MUCH OF THE DAYTIME PERIOD WILL PROBABLY END UP PRECIPITATION FREE. HOWEVER...CLOUDS LIKELY TO PERSIST WITH STRATUS DEVELOPING IN WAKE OF SYSTEM. MOST LIKELY TO GET BREAKS THROUGH THE WESTERN AND SOUTHERN CWA DURING THE AFTERNOON...AND HAVE PUSHED EXPECTED TEMPS TO NEAR 80 THERE... WHILE MORE MID TO UPPER 60S LINGER IN THE FAR EAST. RESULT OF THIS WILL BE GENERATION OF DECENT POTENTIAL INSTABILITY OF 1500-2000 J/KG ACROSS THE AREA...WITH WEAKEST OF THE CAPPING INVERSION NEAR THE MISSOURI RIVER CORRIDOR. SHEAR BECOMES A BIT MORE DISTRIBUTED THROUGH THE EFFECTIVE LAYER...AND FAIRLY CLOSE TO THOSE VALUES FROM THIS EVENING FROM 30 TO 35 KNOTS. A FEW MORE SEVERE STORMS WOULD BE POSSIBLE MAINLY THROUGH THE SOUTHWEST HALF OF THE AREA DURING THE LATER AFTERNOON AND EVENING HOURS...AS INITIATION LIKELY TO BE A RESULT OF WEAK IMPULSE SLIDING UP BACK SIDE OF RIDGE IN THE LATER AFTERNOON AND EARLY EVENING. THE FURTHER ONE GOES INTO THE FORECAST...THE LESS RELIABLE ANY GUIDANCE BECOMES GIVEN THE ABUNDANCE OF CONVECTION...AND THE INCREASINGLY GREAT UNCERTAINTY AS TO WHERE CRITICAL BOUNDARIES MAY LIE. ONE THING FOR SURE...GIVEN THE CLOSED LOW ACROSS THE WESTERN U.S. AND THE SOUTHWEST FLOW ALOFT...DIFFICULT TO PINPOINT ANY TIME FROM MONDAY ON THAT ONE COULD SAY THERE WAS ABSOLUTELY NO CHANCE FOR PRECIPITATION...BUT ON THE SAME FRONT IT CERTAINLY WILL NOT BE AN ALL TIME WASHOUT WITH MANY BREAKS DEFINED ON THE MESOSCALE. MEMORIAL DAY AND MONDAY NIGHT WILL PLACE THE AREA ON THE SOUTHERN FLANK OF A COUPLE OF WAVES MOVING OVER THE RIDGE...SO LIKELY TO HAVE ENHANCEMENT OF PRECIPITATION IN THE NOCTURNALLY FAVORED PERIODS. WHILE A FEW SEVERE STORMS ARE AGAIN WELL WITHIN REASON...HIGH PRECIPITABLE WATER AND FAIRLY SLOW MOVING WIND PROFILES BRING THE CONCERN OF AREAS OF HEAVY RAINFALL...AT THIS RANGE HARD TO DEFINE. AT THE MOMENT...THE PROSPECT FOR MORE SIGNIFICANT CONVECTION AND SEVERE WEATHER WOULD APPEAR TO BE LATE DAY WEDNESDAY INTO THURSDAY...AS DEEP WESTERN CLOSED LOW KICKS STRONGER JET ENERGY INTO THE PLAINS. MOISTURE THROUGH LOWER LEVELS /THUS INSTABILITY/ WILL CONTINUE TO BENEFIT FROM PERSISTENT SOUTHERLY FLOW. TEMPERATURES WILL LIKELY GRAVITATE TO SOMEWHAT ABOVE NORMAL READINGS THROUGH THE UPCOMING WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1103 PM CDT FRI MAY 24 2013 MODELS CONTINUE TO SHOW CEILINGS DETERIORATING INTO MVFR-IFR RANGE LATER TONIGHT AT ALL TAF SITES. STARTING TO SEE HINTS OF MVFR CLOUDS IN EASTERN NEBRASKA AS OF 04Z...SO WILL CONTINUE THIS DOWNWARD TREND IN CEILINGS THROUGH THE FIRST 4-6 HOURS OF TAF PERIOD...WITH NEXT CHANCE OF RAIN EXPANDING INTO SOUTHERN PARTS OF THE AREA ALONG WITH THE LOWER CEILINGS. SOME MID LEVEL INSTABILITY PRESENT AS THE RAIN MOVES INTO SOUTHWEST PARTS OF THE FORECAST AREA...BUT PRECIP MOVES INTO MORE STABLE AIRMASS AS IT PROGRESSES EASTWARD...LEADING TO MORE ISOLATED THUNDER THREAT ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE LEFT MENTION OF THUNDER OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH CANNOT COMPLETELY BE RULED OUT 08Z-15Z...ESPECIALLY AT KSUX. BULK OF MVFR CEILINGS EXPECTED TO BECOME MORE SCATTERED THROUGH THE LATE MORNING/EARLY AFTERNOON SATURDAY...THOUGH WITH MORE ABUNDANT LOW LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS AT TIMES THROUGH THE AFTERNOON. GREATER CHANCE OF MVFR-IFR REDEVELOPMENT SATURDAY EVENING WITH NEXT CHANCE OF CONVECTION SPREADING INTO THE AREA. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN/CHENARD LONG TERM...CHAPMAN AVIATION...
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
347 AM CDT SAT MAY 25 2013 .DISCUSSION... RADAR/SATELLITE LOOP INDICATES THAT THE WEAK MID LEVEL LOW IS LIKELY LOCATED NEAR ABILENE AND 00Z 500MB ANALYSIS CONFIRMS IT IS WARM-CORE IN NATURE. AS IS OFTEN THE CASE WITH WARM-CORE LOWS...CONVECTION IS FIRING BEFORE SUNRISE ACROSS THE HILL COUNTRY WITHIN A WEAK LOW LEVEL JET AXIS WHERE THETA-E ADVECTION AND OROGRAPHIC LIFT ARE OCCURRING. SHORT-TERM MODELS SUCH AS THE HRRR AND RUC SUGGEST THAT SCATTERED CONVECTION WILL CONTINUE TO EXPAND NORTHWARD FROM CENTRAL TEXAS INTO THE WESTERN ZONES DURING THE MORNING HOURS. THE GFS APPEARS TO BE SUFFERING FROM GRID SCALE CONVECTIVE FEEDBACK WHICH IS RESULTING IN VERY HIGH QPF AND CONTAMINATED MASS FIELDS...THUS THE GFS WILL NOT BE USED IN THE SHORT-TERM. THE NAM SEEMS TO BE MATCHING CURRENT TRENDS AND SHORT- TERM MODELS WELL AND THEREFORE IT GIVES CONFIDENCE TO RAISE POPS TODAY. WE EXPECT THE BEST COVERAGE OF CONVECTION IN THE WESTERN ZONES THIS MORNING. SCATTERED CONVECTION WILL BUILD/EXPAND EASTWARD INTO THE EASTERN ZONES DURING THE MIDDAY/AFTERNOON HOURS. THE AIRMASS OVER THE EASTERN ZONES WILL BE A BIT MORE UNSTABLE DUE TO BETTER INSOLATION AND A COUPLE OF STRONG STORMS WITH GUSTY WINDS WILL BE POSSIBLE...BUT DUE TO WEAK SHEAR THE SEVERE THREAT IS LOW. HIGHS TODAY IN THE WESTERN ZONES WILL ONLY BE IN THE UPPER 70S TO LOW 80S DUE TO CLOUDS/RAIN...WITH HIGHS IN THE EASTERN ZONES REACHING THE MID 80S. SCATTERED CONVECTION WILL CONTINUE INTO THE EVENING HOURS BEFORE DISSIPATING WITH LOSS OF HEATING. THE WARM CORE MID LEVEL LOW WILL BE EXITING THE REGION TO THE NORTHEAST TONIGHT...AND THEREFORE THE RAIN CHANCES WILL COME TO AN END. EXPECT A DRY SUNDAY WITH TEMPERATURES REBOUNDING INTO THE MID-UPPER 80S AREA WIDE. AS AN UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTER-MOUNTAIN WEST...A SURFACE LOW WILL DEEPEN IN THE HIGH PLAINS MONDAY. THIS WILL BRING BREEZY SOUTH WINDS TO THE REGION MONDAY WHICH WILL LIKELY PERSIST THROUGH THE WEEK. LOW TEMPS WILL WARM INTO THE 70S AREA WIDE BY MIDWEEK WITH HIGHS GENERALLY IN THE MID 80S EAST TO LOW 90S WEST. THE SOUTHWEST FLOW ABOVE THE SURFACE WILL BRING A THERMAL INVERSION INTO THE AREA. THUS THE FORECAST LOOKS DRY UNLESS/UNTIL FORCING ARRIVES TO WEAKEN THE CAP. MODEL GUIDANCE REMAINS IN POOR TO FAIR AGREEMENT REGARDING THE EVOLUTION/EJECTION OF THE WEST COAST UPPER TROUGH MID-LATE WEEK. THE ECMWF CONTINUES TO SHOW A VERY NEGATIVELY TILTED TROUGH SWINGING THROUGH THE REGION LATE WEDNESDAY AND THURSDAY WHICH WOULD BODE WELL FOR RAIN. BUT IT CONTINUES TO BE THE ONLY MODEL THAT SHOWS THE TROUGH EJECTION LIKE THIS...AND FRANKLY THE 500MB PATTERN IT PRESENTS JUST DOES NOT LOOK REALISTIC. IF IT WERE NOT FOR THE ECMWF BEING THE BETTER OF THE LONG RANGE MODELS...I WOULD DISCOUNT IT ALTOGETHER AND SHOW A DRY FORECAST ON THURSDAY...BUT FOR NOW HAVE RETAINED THE SLIGHT CHANCE POPS. THE GFS/UKMET/GEM FORECASTS SHOW THAT THE UPPER ENERGY NEEDED TO BREAK THE CAP WILL LIKELY REMAIN WELL NORTHWEST OF THE REGION. FURTHERMORE...THE DRYLINE ALSO LOOKS LIKE IT WILL REMAIN TOO FAR TO THE WEST...WITH THE GFS SHOWING IT AS FAR WEST AS THE TX PANHANDLE. STORM MOTIONS WILL GENERALLY BE NORTHEAST AND THIS MEANS STORMS WOULD NOT EVEN HAVE A CHANCE TO PROPAGATE INTO THE CWA EITHER. SO IN SUMMARY THE RAIN CHANCES ON THURSDAY AT THIS POINT ARE HINGING ON THE ECMWF BEING CORRECT...AND THIS MAY BE A BIT OF A LONG SHOT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 84 69 87 69 87 / 40 30 10 5 0 WACO, TX 83 68 87 68 89 / 50 30 10 5 0 PARIS, TX 83 67 85 66 85 / 30 30 10 5 0 DENTON, TX 85 67 86 68 87 / 40 30 10 5 0 MCKINNEY, TX 84 67 85 68 87 / 30 30 10 5 0 DALLAS, TX 85 71 87 70 89 / 30 30 10 5 0 TERRELL, TX 84 67 86 68 88 / 30 30 10 5 0 CORSICANA, TX 84 67 88 68 89 / 30 30 10 5 0 TEMPLE, TX 82 67 87 68 88 / 50 20 10 5 0 MINERAL WELLS, TX 81 66 87 67 89 / 40 20 10 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
246 AM PDT Sat May 25 2013 .SYNOPSIS... Memorial Day Weekend is expected to be a little cooler than average, and a series of weak upper level disturbances will bring the potential for scattered showers Sunday and Monday. The moist, showery weather pattern is expected to linger into late next week. && .DISCUSSION... Today through Sunday...General trof pattern continues to influence the sensible weather over Eastern Washington and Northern Idaho keeping it unsettled at times along with temperatures on the cool side of what would be considered normal this time of year. Last few HRRR model runs hit at surface based convection over the northern mountains after 11AM PDT today and upon further inspection GFS runs for this interval show the cold pool aloft at 500mb helping to keep the instability overhead extends west to overhang parts of the cascades...thus the minor mention of afternoon and early evening thunderstorms has been stretched westward to cover parts of the East Slopes of the Northern cascades roughly north of Leavenworth. Models also hint at a mesoscale shortwave or two producing enough forcing to allow for some minor mention of showers overnight...one near the cascades and the other passing over the Blue Mountains up into North Idaho Panhandle. Sunday the trof overhead is very very cluttered with synoptic and mesoscale shortwave propagation through it which allows for the mention of showers to persist. Forecast temps show a very slight cooling trend as the flow turns a bit more southerly, which is a warm trajectory most of the time, for Sunday. Additionally since the jet stream is south of the forecast area through this time interval resulting in a lowered tropopause (down to near 400mb) some of these showers could produce the typical early spring precipitation type (graupel or soft hail) for a spell along with mixing moderate wind gusts down to the surface which is something to keep in mind over the weekend. /Pelatti Sunday Night through Wednesday: The cool upper level trough that has been anchored over the Pacific Northwest since Wednesday is expected to pivot into western Montana Sunday night into Monday bringing scattered showers to the eastern third of Washington and northern Idaho. Despite the displacement of this upper low, our weather pattern isn`t expected to change much. There is good agreement between the medium range models that the Polar Jet will dive into southern Oregon and carve another upper level trough over the Pacific Northwest. The best jet dynamics (Q-Vector Divergence) Monday night into Tuesday should be over southern Oregon into the Great Basin, but there will be enough moisture and deep layer instability with the weakening frontal occlusion to maintain a good chance of showers Tuesday and Tuesday night. Depending on the timing of this system, we may need to add a mention of thunderstorms on Tuesday. The 00z GFS, Canadian and ECMWF are in pretty good agreement with a weak, negatively tilted trough over central and western Washington. The GFS and ECMWF are producing precipitation that looks convectively driven over the north Cascades. The potential for thunderstorms over the burn scars around Wenatchee, Ellensburg, and Chelan will be a concern through the summer and we will continue to monitor patterns like this one closely for mudslides and debris flows. The axis of a west to east oriented upper trough is expected to linger over the Pacific Northwest Wednesday and through the end of the week. It does look like Tuesday`s frontal occlusion will bring the most widespread shower activity to the region this week, but afternoon and early evening showers will be in the forecast for much of the week. /GKoch Wednesday Night through Friday Night: Through this time frame we continue to see an unsettled pattern that will continue to feature the chance for precipitation across most of the Inland NW especially for the higher terrains of the ID Panhandle along with Cascade Crests earlier in the period. Models are in pretty good agreement through Friday Afternoon by keeping a large scale negatively tilted trough pattern in place allowing for moisture to flow in behind the low center that pushes to our SE throughout the night on Wednesday. With the increased moisture, there will be thick cloud cover keeping temps in the lower 60s and 70s for most correlating to below normal temps for this time of year. Low temps will follow the same pattern of a couple degrees below normal due to the lack of daytime heating. Towards the end of the period models are indicating a ridge builds behind the exiting trough which should help to diminish the precipitation threat...lower the cloud coverage and ultimately push temperatures closer to seasonal averages as we approach next weekend. Overall not many changes were made to the forecast..just tinkered with the POPs slightly to reflect most recent model data and trended the temps in the same manner. /Fliehman && .AVIATION... 06Z TAFS: The Inland Northwest will be under a broad area of low pressure through tonight. Mid to high level cloud cover is expected over much of the region through Saturday morning. Some low level moisture across the northern valleys and Panhandle valleys tonight may result in some patchy fog by the morning hours. Another relatively weak system for Saturday afternoon will produce mainly mountain showers. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 63 44 65 46 65 47 / 20 10 30 50 30 10 Coeur d`Alene 63 42 65 45 64 44 / 20 20 30 50 40 10 Pullman 64 43 63 44 65 46 / 10 10 30 50 20 20 Lewiston 71 48 70 50 71 51 / 10 10 30 50 20 20 Colville 67 41 72 45 69 44 / 40 30 20 20 50 20 Sandpoint 63 39 66 43 63 42 / 30 20 20 40 50 20 Kellogg 61 44 63 46 62 47 / 40 20 30 60 50 20 Moses Lake 72 46 73 49 73 50 / 10 10 30 20 10 20 Wenatchee 68 47 70 49 71 51 / 10 10 30 10 10 20 Omak 68 41 71 45 70 46 / 30 20 30 10 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT FRI MAY 24 2013 .UPDATE... ISSUED AT 646 PM CDT FRI MAY 24 2013 QUICK UPDATE TO REFLECT THE FASTER TIMING OF PRECIPITATION CURRENTLY ACROSS WESTERN/CENTRAL MINNESOTA. THIS ACTIVITY IS RIDING ALONG MID LEVEL FRONTOGENESIS AND WARM AIR ADVECTION...AND COMBINED WITH SOME DECENT UPPER LEVEL FORCING / PV ADVECTION. MOST OF THE MESO-MODELS AND 18Z GUIDANCE SHOWS THIS SLIDING SOUTH/EAST MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER THROUGH THE OVERNIGHT. SO HAVE SPED UP PRECIPITATION WORDING TO ACCOUNT FOR THIS. OTHERWISE...FORECAST REMAINS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 334 PM CDT FRI MAY 24 2013 AT 3 PM...A 1003 MB HIGH PRESSURE SYSTEM...CENTERED OVER LAKE MICHIGAN...KEPT SKIES PARTLY SUNNY ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MEANWHILE FURTHER WEST...A SHORT WAVE WAS PRODUCING SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN QUARTER OF THE DAKOTAS AND WESTERN MINNESOTA. THE MESO AND DETERMINISTIC MODELS ARE CONTINUING TO STRUGGLE WITH THE EASTWARD PROGRESS OF THIS PRECIPITATION TONIGHT. THE ECMWF AND HRRR MOVE THIS PRECIPITATION ACROSS MOST OF FORECAST AREA BY 25.06Z. MEANWHILE THE NMM...ARW...GFS...GEM...RAP... AND NAM MAINLY CONFINE THE PRECIPITATION WEST OF THE MISSISSIPPI RIVER THIS EVENING...AND THEN MOVES IT ACROSS THE REMAINDER OF THE AREA OVERNIGHT. SINCE THE CONVECTION ACROSS THE DAKOTAS WILL BE MOVING INTO AN AREA WITH LESS FRONTOGENETIC FORCING...MOISTURE TRANSPORT...WEAK ISENTROPIC LIFT...AND DRIER AIR...DECIDED TO TREND THE FORECAST TOWARD THE LATTER MODEL SET. IN ADDITION...THE RADAR ECHOS ACROSS WESTERN MINNESOTA ARE SHOWING A DECREASING TREND. EVEN BY DOING THIS...THERE IS SOME VARIATIONS AMONGST THEM...SO TRIED TO GO WITH AN ENSEMBLE APPROACH WHEN ASSIGNING THE HOURLY PRECIPITATION CHANCES. THE HIGHEST PRECIPITATION CHANCE AND AMOUNTS /UP TO A HALF INCH/ WILL BE FOUND ACROSS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. ON SATURDAY...THE SHORT WAVE WILL MOVE EAST SOUTHEAST ACROSS IOWA. AS THIS OCCURS...THE 850 MB MOISTURE TRANSPORT AND ISENTROPIC LIFT WILL GRADUALLY WEAKEN. AS A RESULT...WENT WITH A DECREASING TREND IN THE PRECIPITATION TRENDS FROM LATE MORNING INTO THE AFTERNOON. ADDITIONAL RAINFALL AMOUNTS WILL BE LESS THAN 2 TENTHS OF AN INCH. WITH THE 24.12Z AND 24.18Z MODELS IN GOOD AGREEMENT THAT THERE WILL BE LESS THAN 100 J/KG CAPES...JUST KEPT AN ISOLATED THUNDERSTORM CHANCE MAINLY WEST AND SOUTH IF THE INTERSTATE 94 CORRIDOR. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 334 PM CDT FRI MAY 24 2013 FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE WARM FRONT WILL REMAIN WELL SOUTHWEST OF THE FORECAST AREA. AS A RESULT... SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN WILL REMAIN CLOUDY WITH PERIODIC SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM. OVER THE PAST 3 DAYS...THE CONSALL HAS CONTINUED TO TREND TOWARD COOLER HIGH TEMPERATURES FOR SUNDAY. IT NOW HAS HIGH TEMPERATURES AROUND 60. MEANWHILE THE ECMWF ONLY HAS HIGH TEMPERATURES IN THE LOWER 50S FOR THESE AREAS. SINCE THE ECMWF TYPICALLY VERIFIES THE BEST FOR THIS TIME PERIOD...WENT WITH A BLEND OF THE CONSALL...CONSALLBC...AND ECMWF. FROM MEMORIAL DAY INTO TUESDAY...THE MODELS ARE CONTINUING TO SHOW THAT A WARM FRONT WILL MOVE NORTHWARD INTO THE AREA. THIS WILL ALLOW ML CAPES TO CLIMB INTO THE 1K TO 3K J/KG RANGE. AS A RESULT...EXPECT THE THUNDERSTORM CHANCES TO INCREASE DURING THIS TIME PERIOD. THE 0-3KM SHEAR WOULD BE FAVORABLE FOR THE POSSIBILITY THAT A FEW THUNDERSTORMS MAY BE CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. FROM TUESDAY NIGHT INTO FRIDAY...THE MODELS CONTINUE TO STRUGGLE ON WHERE THE WARM SECTOR WILL BE LOCATED. THIS GREATLY AFFECTS THE WHERE THE PRECIPITATION MAY BE LOCATED. IN ADDITION...IT WILL ALSO AFFECT THE SHEAR AND INSTABILITY...THUS...THERE IS A LOT OF UNCERTAINTY ON WHETHER THERE WILL BE ANY SEVERE WEATHER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1148 PM CDT FRI MAY 24 2013 A BAND OF LIGHT TO MODERATE RAIN HAS SET UP ALONG AND JUST TO THE WEST OF THE MISSISSIPPI RIVER AND IS EXPECTED TO PERSIST THROUGH THE OVERNIGHT HOURS. AS THE FORCING WEAKENS LATER THIS MORNING...EXPECT THAT THE RAIN WILL COME TO AN END THOUGH SOME MVFR CEILINGS WILL BECOME POSSIBLE AT RST. CURRENT THINKING IS THAT CONDITIONS SHOULD MAINLY BE DRY THROUGH THE REST OF THE DAY WITH OVERALL FORCING BEING WEAK INTO THE NIGHT. THE MAIN QUESTION WILL BE WHETHER THERE WILL BE ENOUGH LOW LEVEL MOISTURE TRAPPED UNDER THE SHALLOW INVERSION AROUND 3KFT TO PRODUCE SOME MVFR CEILINGS...PARTICULARLY AT RST. WITH CONFIDENCE NOT AS HIGH AS IT PREVIOUSLY WAS...HAVE REMOVED IT FROM THE FORECAST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...ZT SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1011 AM CDT SAT MAY 25 2013 .DISCUSSION... ISSUED 1011 AM CDT SAT MAY 25 2013 OVERNIGHT MCS FROM IOWA HAS BEEN SHOWING SOME WARMING CLOUD TOPS AS IT DROPS SOUTHEAST INTO WESTERN ILLINOIS. HAVE BEEN SEEING SOME LIGHT ECHOES ON RADAR AS FAR EAST AS THE INDIANA BORDER...BUT THE AIR MASS OVER CENTRAL ILLINOIS IS VERY DRY AS EVIDENCED BY THE MORNING SOUNDING AND LAPS ANALYSIS...SO A LOT OF THIS HAS BEEN ALOFT. FINALLY SEEING SOME MEASURABLE RAIN AROUND GALESBURG THOUGH. RAP AND HRRR MODELS DOING A REASONABLE JOB WITH THE MCS ITSELF...AND SHOW THE RAIN MOST WIDESPREAD THROUGH EARLY AFTERNOON BEFORE BREAKING UP. MOST OF THE THUNDERSTORMS HAVE BEEN DROPPING SOUTHEASTWARD TOWARD WEST CENTRAL ILLINOIS...SO HAVE CUT BACK SOME ON THE THUNDER CHANCES...ESPECIALLY NORTH OF I-74. HAVE SENT OUT SOME UPDATES TO SIGNIFICANTLY INCREASE THE RAIN CHANCES ACROSS THE NORTHWEST HALF OF THE CWA...WITH LESSER CHANGES NEEDED ACROSS THE SOUTHEAST. GEELHART && .AVIATION... ISSUED 657 AM CDT SAT MAY 25 2013...FOR THE 12Z TAFS SHOWERS ARE ADVANCING INTO THE DRY AIR MASS ACROSS CENTRAL IL FROM THE W-NW. RADAR IMAGES ARE A LITTLE MISLEADING WITH MOST OF THE RETURNS BELOW 40 DBZ ASSOCIATED WITH VIRGA AT THIS POINT. THE AIRMASS WILL EVENTUALLY SUCCUMB TO THE ISENTROPIC LIFT...MOISTURE CONVERGENCE AND STRENGTHENING LOW LEVEL JET...AS HEAVIER RAINS AND A FEW THUNDERSTORMS BECOME MORE PROMINENT THIS AFTERNOON AND TONIGHT. MOST AREAS SHOULD REMAIN VFR WITH CLOUD HEIGHTS ABOVE 3K FT. VIS MAY DIP TO MVFR 3-5SM DURING HEAVIER SHOWERS AND STORMS...BUT ANY PERIODS OF IFR CONDITIONS DURING STORMS WILL BE BRIEF. FREQUENT RAINS AND ISOLATED THUNDERSTORMS WILL CONTINUE TONIGHT DESPITE LOSING LOW LEVEL INSTABILITY. A SATURATED AIRMASS AND WEAK INSTABILITY ABOVE AN ELEVATED MIXED LAYER WITH PROVIDE ENOUGH SUPPORT FOR SOME STORMS AND PERSISTENT RAIN. WINDS WILL START OUT EASTERLY...THEN VEER TO THE SOUTHEAST AND INCREASE INTO THE 10-14KT RANGE AS THE NEXT MESO-VORTEX ARRIVES FROM THE WEST LATER THIS MORNING AND AFTERNOON. WINDS MAY BACK TO THE EAST AGAIN THIS EVENING AS WARM FRONTOGENESIS INCREASES ACROSS CENTRAL IL FROM WEST TO EAST. SHIMON && .PREV DISCUSSION... ISSUED 242 AM CDT SAT MAY 25 2013 UNSETTLED WEATHER THROUGH THE MEMORIAL DAY WEEKEND...FOLLOWED BY MUCH WARMER/DRIER CONDITIONS FOR THE MIDDLE AND END OF NEXT WEEK. SHORT TERM...TODAY THROUGH MONDAY CONVECTION CURRENTLY DEVELOPING ALONG THE NOSE OF A 45-50KT LLJ OVER NEBRASKA IS EXPECTED TO TRACK E/SE INTO THE AREA TODAY. MAIN QUESTION WILL BE HOW FAR EAST THE PRECIP CAN PENETRATE INTO SPRAWLING SURFACE RIDGE AXIS EXTENDING FROM THE GREAT LAKES TO THE GULF COAST. 00Z KILX UPPER AIR SOUNDING SHOWED A VERY DRY PROFILE FROM THE SURFACE UP TO ABOUT 500MB. ANY PRECIP MOVING INTO THIS HOSTILE ENVIRONMENT WILL INITIALLY EVAPORATE UNTIL THE AIRMASS IS SUFFICIENTLY MOISTENED. DUE TO THE CONTINUED DRY E/NE LOW-LEVEL FLOW...HAVE REMOVED POPS ACROSS EAST-CENTRAL AND SOUTHEAST ILLINOIS FOR THE MORNING HOURS. FURTHER WEST...HIGH-RES HRRR SUGGESTS NEBRASKA CONVECTION WILL EVENTUALLY SPREAD INTO WEST-CENTRAL ILLINOIS TOWARD MIDDAY. WILL THEREFORE CARRY CHANCE POPS DURING THE MORNING...THEN LIKELY THIS AFTERNOON FOR LOCATIONS ALONG/WEST OF I-55. INITIAL AREA OF CONVECTION WILL DISSIPATE AS IT MOVES INTO EAST-CENTRAL ILLINOIS LATER THIS AFTERNOON AND EVENING. MEANWHILE...LOW-LEVEL JET WILL ONCE AGAIN STRENGTHEN AND FOCUS A RENEWED ROUND OF SHOWERS/THUNDER UPSTREAM ACROSS IOWA TONIGHT. THIS ACTIVITY IS THEN EXPECTED TO TRACK E/SE INTO CENTRAL ILLINOIS LATE TONIGHT INTO SUNDAY. WITH AIRMASS MOISTENED FROM INITIAL PRECIP TODAY...THINK RAIN CHANCES WILL BE HIGHER ACROSS THE BOARD TONIGHT/SUNDAY. WILL THEREFORE CARRY LIKELY POPS EVERYWHERE EXCEPT THE FAR SE CWA. ADDITIONAL SHOWERS/STORMS WILL FIRE ON MONDAY...AS PERSISTENT FRONTAL BOUNDARY FINALLY BEGINS TO SHIFT SLOWLY NORTHWARD ACROSS THE AREA. WILL CONTINUE TO HIT POPS HARD...ESPECIALLY ACROSS THE CENTRAL AND NORTHERN ZONES. TOTAL RAINFALL FROM THIS MULTI-DAY EVENT WILL BE LIGHTEST ALONG THE ILLINOIS/INDIANA BORDER WHERE AMOUNTS OF ONE HALF TO ONE INCH WILL BE COMMON. HIGHER RAIN TOTALS WILL BE FOCUSED FURTHER WEST...ESPECIALLY WEST OF I-55 WHERE ONE AND A HALF TO TWO INCHES WILL BE LIKELY. LONG TERM...TUESDAY THROUGH FRIDAY AS UPPER TROUGH DIGS OVER THE WESTERN CONUS...DOWNSTREAM RIDGE WILL BUILD ACROSS THE MIDWEST/OHIO RIVER VALLEY. THIS WILL FINALLY GIVE THE SURFACE FRONT A GOOD PUSH NORTHWARD BY TUESDAY...RESULTING IN LOWER POPS AND HIGHER TEMPS. WILL ONLY CARRY LOW CHANCE POPS ACROSS THE FAR NORTHERN CWA...WHILE HIGH TEMPS CLIMB INTO THE LOWER TO MIDDLE 80S. AFTER THAT...MODEL SOLUTIONS VARY SOMEWHAT CONCERNING HOW QUICKLY THE UPPER RIDGE EVENTUALLY BREAKS DOWN. GIVEN AMPLIFIED PATTERN...THINK THIS WILL BE LATER RATHER THAN SOONER...SO HAVE GONE WITH A VERY WARM AND DRY FORECAST THROUGH THURSDAY. WEAKENING FRONTAL BOUNDARY MAY PUSH INTO THE REGION BY THE END OF THE WEEK...SO HAVE INCLUDED CHANCE FOR SHOWERS/THUNDER ON FRIDAY WITH CONTINUED WARM TEMPS WELL INTO THE 80S. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
701 AM EDT SAT MAY 25 2013 .AVIATION... //DISCUSSION... AMBIENT DRY AIR THROUGH AN IMPRESSIVE DEPTH WILL KEEP THE DOOR SHUT ON PRECIPITATION CHANCES AS MIDLEVEL ENERGY PASSES THE STATE TO THE SOUTH. THE ONLY IMPACT ON AVIATION CONDITIONS WILL BE SOME BKN-OVC CEILINGS AT UPWARDS OF 25 KFT THIS MORNING. SURFACE WINDS TODAY ARE EXPECTED TO EMERGE LIGHT NORTHERLY COMMENCING ON BOUNDARY LAYER GROWTH. MODELS ARE HINTING AT SOME CUMULUS DEVELOPMENT THIS AFTERNOON BUT THAT SEEMS SUSPECT ATTM. //DTW THRESHOLD THREATS... * NONE. && .PREV DISCUSSION...ISSUED 325 AM EDT SAT MAY 25 2013 SHORT TERM...TODAY AND TONIGHT EARLY MORNING MSAS ANALYSIS IS SHOWING A SURFACE RIDGE EXTENDING SOUTHWARD THROUGH THE LAKE SUPERIOR/MICHIGAN/HURON BASINS. THE BEST SURFACE RIDGING COMPONENT INSIDE OF THE CWA IS ACROSS THE NORTHERN THUMB DOWN INTO PORT HURON. PERUSING THROUGH THE SURFACE OBSERVATIONS...FEELING IS THE BEST POTENTIAL FOR ANY FROST FORMATION WILL BE IN THE THUMB AND LOW LYING AREAS OF THE GLACIAL TERRAIN WITH THE LOCAL OFFICE TEMPERATURE AT 33 DEGREES AS OF 230 AM LDT. WILL MAINTAIN THE FROST ADVISORY AS IS FOR SIMPLICITY. THERE HAS BEEN A DECENT RADAR PRESENTATION OVERNIGHT ACROSS PORTIONS OF MN/WI/IA TIED TO THE AGEOSTROPHIC RESPONSE OF MERGING AND SHEARING OF SHORTWAVE ENERGY. ONE HR PRECIPITATION AMOUNTS HAVE BEEN LESSENING AS THE PRECIPITATION/VIRGA PUSHES FARTHER TO THE SOUTHEAST. THIS IS LIKELY IN RESPONSE TO INCREASING CONFLUENCE ALOFT AS THE ENTRANCE REGION LIES DIRECTLY OVER LOWER MICHIGAN. THE BEST UPPER LEVEL FORCING IN THE FORM OF 700-500MB FRONTOGENESIS WILL BRUSH FAR SOUTHWESTERN SECTIONS OF THE STATE BETWEEN 12-15Z...BEFORE PASSING HARMLESSLY TO THE SOUTH. THE AMOUNT OF AMBIENT DRY AIR IN THE LOWEST 12 KFT AGL SUPPORTS VIRTUALLY NO PRECIPITATION POTENTIAL TODAY. THE PREFERENCE REGARDING HIGH CLOUD PROG LIES WITH THE 25.05Z RUC WHICH BRINGS HIGH CLOUDS INTO THE SOUTHWESTERN 2/3RDS OF THE CWA BETWEEN 9-16Z THIS MORNING. INCREASED INSOLATION WITH SOME MODERATION OF THE AIRMASS WILL SUPPORT A SOLID 3-8F DEGREE UPTICK IN HIGH TEMPERATURES. EXPECT READINGS TO RANGE FROM THE MIDDLE 50S IN THE FAR NORTHERN THUMB/LAKE HURON SHORELINE TO THE MIDDLE 60S DETROIT SOUTHWARD. SURFACE HIGH PRESSURE WILL EXPAND ACROSS THE CENTRAL GREAT LAKES TONIGHT...BRINGING THE PROSPECTS OF ANOTHER COOL TO COLD NIGHT. DIFFERENTIAL AIRMASS RECOVERY SHOULD BE GOOD FOR A FEW DEGREES OFF THIS MORNINGS MINS. WORKED WITH A BLEND OF UNDERCUT GUIDANCE WITH SOME PERSISTENCE. EXPECTED LOWS TONIGHT SHOULD RANGE FROM THE LOWER TO MIDDLE 30S IN THE THUMB TO LOWER 40S SOUTHEAST OF THE TERRAIN. LONG TERM...SUNDAY THROUGH FRIDAY LOWER MICHIGAN WILL RESIDE BETWEEN A HIGH AMPLITUDE RIDGE ACROSS THE UPPER MIDWEST AND A DEEP UPPER LOW LIFTING FROM NEW ENGLAND INTO THE CANADIAN MARITIMES DURING THE LATER HALF OF THE WEEKEND...SUSTAINING A CONFLUENT FLOW ALOFT. AT THE SFC...THIS WILL TRANSLATE TO HIGH PRESSURE BUILDING FROM THE UPPER GREAT LAKES ON SUNDAY TO THE EASTERN GREAT LAKES ON MONDAY. OTHER THAN THE POTENTIAL FOR SOME HIGH CLOUDS...SKIES SHOULD REMAIN MAINLY CLEAR WITH VERY DRY AIR OVERHEAD. TEMPS WILL SLOWLY MODERATE...LEADING TO AN OVERALL WARMING TREND HEADING INTO MEMORIAL DAY. EXPECT MIXING DEPTHS MAY OVERACHIEVE WITH PLENTY OF SUNSHINE AND SUBSTANTIAL LOW LEVEL DRY AIR. THIS SUPPORTS LEANING TOWARD THE HIGHER END OF GUIDANCE MAX TEMPS /MID TO UPPER 60S SUNDAY AND AROUND 70 MONDAY/. THE DRY AIRMASS AND WEAK SFC GRADIENT WILL SUPPORT OPTIMAL RADIATIONAL COOLING POTENTIAL...SO MINS SUN NIGHT WILL CONTINUE TO BE QUITE COLD FOR LATE MAY /UPPER 30S TO MID 40S/. THE MID LEVEL RIDGE IS FORECAST TO BREAK DOWN EARLY NEXT WEAK AS NUMEROUS SHORT WAVE IMPULSES ARE EJECTED OUT OF THE LONG WAVE TROUGH OVER THE WRN US AND ACROSS THE CNTRL/NRN PLAINS. THE BULK OF THE 00Z MODEL SUITE SUGGEST MCS DEVELOPMENT ACROSS THE UPPER MIDWEST OR WRN GREAT LAKES MON AFTERNOON/NIGHT AS LOW LEVEL INFLOW STRENGTHENS. THE POTENTIAL FOR REMNANT MCS ACTIVITY TO ADVANCE INTO SE MI REMAINS HIGHLY UNCERTAIN AT THIS TIME. WHILE SEVERAL MODEL SOLUTIONS ARE QUITE BULLISH WITH QPF OVER SE MI MON NIGHT AND TUES...THERE IS LIKELY SOME SEMBLANCE OF CONVECTIVE FEEDBACK IN THE MODELS. THERE IS ALSO CONCERN THAT THE MODELS HAVE A POOR HANDLING OF MCS PROPAGATION...WHICH COULD LEAD TO REMNANT CONVECTION BEING MUCH FARTHER SOUTH. THUS PLAN TO CARRY VERY LOW CHANCE POPS TUESDAY. PERSISTENT LOW LEVEL S-SWLY FLOW SHOULD HOWEVER LIFT A WARMER AND MORE HUMID AIRMASS INTO SRN LOWER MI BY MID WEEK...MARKED BY THE PASSAGE OF A SFC WARM FRONT. THIS WILL JUSTIFY A CHANCE OF SHOWERS/THUNDERSTORMS LATE TUES THROUGH WED. THE ECMWF REMAINS STEADFAST IN DEVELOPING A MORE AMPLIFIED UPPER TROUGH OVER THE WRN US BY MIDWEEK AS ENERGY EJECTS OUT OF THE GULF OF ALASKA AND INTO THE WEST COAST. A SEASONALLY STRONG UPPER JET WITHIN THE BASE OF THE DEEP GULF OF ALASKA UPPER LOW AND CURRENT AMPLIFIED NATURE OF THE FLOW LENDS SUPPORT TO THE ECMWF. THIS SOLUTION BUILDS THE SUBTROPICAL RIDGE FARTHER NORTH INTO THE ERN US LATE IN THE WEEK AND SUGGESTS SE MI MAY BE CAPPED. EVEN THE LESS AMPLIFIED GFS BUILDS MID LEVEL HEIGHTS SUBSTANTIALLY ACROSS SE MI. THUS THE FORECAST FOR THE LATER HALF OF NEXT WEEK WILL HAVE VERY LOW POPS WITH MAX TEMPS WELL INTO THE 80S. MARINE... A STABLE ANTICYCLONE WILL EXPAND ACROSS THE GREAT LAKES THROUGH THE HOLIDAY WEEKEND. THIS WEATHER FEATURE WILL BE RESPONSIBLE FOR MORE TYPICAL MARINE CONDITIONS FOR LATE MAY. WAVE HEIGHTS ARE ONLY EXPECTED TO RANGE IN THE 1 TO 2 FOOT RANGE IN MANY AREAS THROUGHOUT THE WEEKEND. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060- MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082- MIZ083...UNTIL 8 AM SATURDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....CB SHORT TERM...CB LONG TERM....SC MARINE.......CB YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
600 AM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 344 AM CDT SAT MAY 25 2013 INITIAL SHIELD OF WAA SHOWERS THAT WAS DEPICTED WELL ON 310K ISENTROPIC SFC ON THE NAM/GFS IS FADING AWAY ACROSS WRN WI AS THIS BATCH OF FORCING WEAKENS AND DIVES SOUTHEAST. IN ITS WAKE...WE HAVE WAA AT H85...BUT THE DEEPER MOISTURE HAS PUSHED EAST...SO PRECIP HAS CUT OFF PRETTY QUICK. WITH THE WAA AND WEAK MOISTURE TRANSPORT...SHOULD BE ABLE TO GET SOME LIGHT SHOWERS/SPRINKLES ACROSS MN THIS MORNING...BUT NOT MUCH MORE THAN THAT. BEST CHANCE FOR RAIN TODAY WILL BE ACROSS SRN MN. WARM FRONT NOW CAN BE FOUND ACROSS SOUTH CENTRAL NEB INTO NE KAN...WITH A STRONG LLJ OVERRUNNING IT. THIS HAS GENERATED AN MCS OVER ERN NEB THIS MORNING. THUNDER STARTING TO INCREASE ACROSS IA AS WELL AS THE LLJ HAS SLOWLY WORKED EAST. MOST OF THIS THUNDERSTORM ACTIVITY WILL REMAIN SOUTH OF MN THROUGH THE DAY...BUT ALL HI-RES MODELS SHOW SOME OF THIS MOISTURE FROM IA SNEAKING UP INTO SOUTH CENTRAL MN THROUGH MORNING...WHERE SOME HIGH CHANCE/LIKELY POPS ARE CONTINUED THROUGH THE MORNING HOURS. FOR THE AFTERNOON...PRECIP LOOKS TO SHUT OFF...BUT WE WILL BE STUCK WITH FAIRLY BROAD CLOUD COVER...WITH THE ONLY HOPE FOR SOME BREAKS ACROSS THE NE MPX CWA THANKS TO THE INFLUENCE OF A DRY SFC HIGH THAT WILL BE SPLAYED OUT ACROSS THE GREAT LAKES. GIVEN THE CLOUD COVER WILL BE A COOL DAY...WITH TEMPERATURES IN SOUTH CENTRAL MN LIKELY STAYING IN THE 50S THANKS TO BETTER RAIN CHANCES AND THICKER CLOUD COVER. FOR TONIGHT...ALL MODELS SHOW ANOTHER ROUND OF CONVECTION RIDING ALONG NORTH OF THE WARM FRONT...KIND OF LIKE WHAT WE HAVE SEEN OVERNIGHT TO OUR SOUTHWEST. QUESTION BECOMES HOW FAR NORTH DOES THE ACTIVITY MAKE IT. CONSENSUS PLACEMENT FROM THE WARM FRONT PLACES IT BY 12Z SUNDAY MORNING FROM THE BLACK HILLS...DOWN THROUGH YANKTON...SD AND THEN DOWN TO THE CENTRAL IA/MO BORDER. ONCE AGAIN...WILL SEE A LLJ OVERRUNNING THIS FRONTAL FEATURE...WHICH SHOULD GENERATE YET ANOTHER MCS. GIVEN THE FRONTS PLACEMENT TO OUR SOUTHWEST...BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE SOUTH OF THE UPPER MN RIVER IN SW MN INTO SC MN. FOR TIMING...FAVORED HIGHEST POPS TO AFTER 6Z...AS CONVECTION SHOULD FIRE THIS EVENING OVER SE SODAK INTO NE NEB...THEN HEAD TOWARD SW/SC MN. ALL OF THIS ACTIVITY WOULD BE ELEVATED...SO SEVERE THREAT LOOKS MINIMAL...WITH THE MAIN IMPACT BEING THE POTENTIAL FOR HEAVY RAIN...AS WE HAVE SEEN THIS EVENING IN NEB. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 344 AM CDT SAT MAY 25 2013 THE LONG TERM PERIOD CONTINUES TO LOOK INCREASINGLY WET AND STORMY. THIS IS DUE TO THE REGION BEING SANDWICHED BETWEEN A BUILDING UPPER HIGH ALONG THE EASTERN SEABOARD... WHILE A VERY DEEP TROUGH PUSHES INTO THE WESTERN HALF OF THE UNITED STATES. THERE SHOULD BE A ROUND OF CONVECTION PASS ACROSS SOUTHERN MN SUNDAY MORNING...VERY SIMILAR TO WHAT HAS BEEN ONGOING OVERNIGHT ACROSS NE/IA. THE STORMS TO OUR SOUTH CURRENTLY HAVE BEEN BASICALLY SUB SEVERE... BUT VERY EFFICIENT RAIN PRODUCERS... WITH UPWARDS OF 1.75 INCHES OF RAIN IN THREE HOURS. THIS IS THE TREND EXPECTED SUNDAY MORNING ACROSS SOUTHERN MN... ESPECIALLY THE I-90 CORRIDOR. THEREAFTER... A SIGNIFICANT DIMINISHING TREND IN THE PRECIPITATION FOR SUNDAY AFTERNOON AND EVENING WITH THE NMM/ARW WRF/S IN AGREEMENT. MEMORIAL DAY IS LOOKING A LITTLE WORSE NOW WITH EVEN THE ECMWF DRIVING A WAVE OF CONVECTION ACROSS THE FA DURING THE DAY AND EVENING. JUST GENERAL THUNDER INDICATED ON SWODY2 WHICH SEEMS REASONABLE WITH THE MAIN WARM FRONTAL BOUNDARY MEANDERING FROM THE CENTRAL PLAINS TO THE LOWER OHIO VALLEY. AGAIN... THE CONCERN WILL BE LOCALIZED HEAVY RAINFALL. THE DETERMINISTIC RUNS WOULD ALSO SUGGEST ANOTHER ROUND OF CONVECTION FOR US LATE MONDAY NIGHT AND TUESDAY MORNING... ESPECIALLY ACROSS SOUTHERN MN. THIS REPEATING ROUNDS OF POTENTIAL CONVECTION IS DISTURBING WITH AREAS OF SOUTHERN AND ESPECIALLY SOUTHEAST MN RUNNING WELL ABOVE NORMAL ON RAINFALL FOR THE MONTH OF MAY. THE THREAT FOR FLASH FLOODING WILL BE ON THE INCREASE. IT WAS POINTED OUT ON FRIDAY IN THE WEATHERTALK FROM DR SEELY AT THE UMN THAT SINCE MARCH 1ST...(METEOROLOGICAL SPRING) IT HAS BEEN ONE OF THE WETTEST IN HISTORY FOR MANY AREAS OF MN. ADD THIS TO THE CIPS ANALOGS FOR 5 DAYS FROM NOW AND ONE SEES A VERY WET PATTERN ACROSS ALL OF THE REGION WITH 2 INCHES OF RAINFALL EXCEEDING 30 PERCENT PROBABILITY WITH EVEN WIDESPREAD 3 INCHES HAVING A 10 PERCENT PROBABILITY. THIS IS IN ADDITION TO THE RAINS SUNDAY THROUGH TUESDAY. NOT SURPRISING THEN ARE THE RUN TOTALS FROM THE GFS AND ECMWF THROUGH NEXT FRIDAY WHICH PAINT THE LANDSCAPE WITH 2 TO 4 INCHES OF RAIN... WITH 4 INCHES OR MORE SOUTH OF US. DIGRESSING FOR A MOMENT... ONE OF THE MONTHS/YEARS THAT HAS SHOWN UP IN THE CIPS ANALOGS RECENTLY IS JULY 1993... WITH RECORD FLOODING IN THIS PART OF THE COUNTRY. A REVIEW FROM NCDC SHOWED LOW PRESSURE ALOFT OVER THE WESTERN HIGH PLAINS WITH A STRONG SW JET AT 250 MB ACROSS OUR AREA. THE BERMUDA HIGH HAD PUSHED INTO THE SOUTHEAST UNITED STATES WITH ORGANIZED 850 MB WINDS FROM THE WESTERN GULF OF MEXICO TO THE WESTERN GREAT LAKES. HENCE... THE FLOODING POTENTIAL IS A BIG CONCERN FOR THE WEEK AHEAD AS THE PATTERN IN THE SUMMER OF 1993 MIMICS OUR WEEK AHEAD QUITE WELL. FINALLY... AND JUST AS IMPORTANT... WILL BE THE THREAT FOR SEVERE WEATHER NEXT WEEK AS THE WARM FRONT LIFTS NORTH INTO OUR AREA BEGINNING ON TUESDAY. NOT TOO CONCERN ABOUT SEVERE ON SUNDAY. THE CHANCE INCREASES SOME ON MONDAY (ISOLATED)...ESPECIALLY IF AFTERNOON CONVECTION DEVELOPS AS DEEP LAYER SHEAR RISES. THEN FROM TUESDAY ONWARD THERE IS SEVERE POTENTIAL EACH DAY. THE CIPS ANALOGS CONTAIN MANY SEVERE REPORTS FOR US FOR THE MIDDLE OF NEXT WEEK WITH SEVERE PROBABILITIES FROM 15 TO 30 PERCENT FOR THE ENTIRE FA USING THE TOP 8 ANALOGS. A COLD FRONT MAY MOVE ACROSS THE FA FROM FRIDAY INTO SATURDAY...DIMINISHING THE SEVERE WEATHER THREAT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 600 AM CDT SAT MAY 25 2013 LOTS OF CONVECTION ON THE RADAR...BUT IT IS ALL WELL TO THE SOUTH. MAY SEE A FEW SPRINKLES/LIGHT SHOWERS ACROSS MN THROUGH THE MORNING...WITH ANYTHING MORE SUBSTANTIAL STAYING CONFINED TO THE I-90 CORRIDOR. FOR THE REST OF THE DAY...WILL HAVE TO TRACK MVFR CIGS EMANATING FROM THE TSRA ACTIVITY IN IOWA. CONTINUED TO FAVOR A HRRR/RAP DEPICTION FOR THE HANDLING OF THESE LOW CLOUDS...KEEPING MVFR CIGS DURING THE DAY CONFINED TO RWF. WITH SE FLOW...NAM ALONG WITH THE RAP SHOW MVFR CIGS WORKING NW INTO NODAK...WHICH SHOULD BRING MVFR CIGS TO AXN THIS AFTERNOON OR EVENING. MSP/STC LOOK TO BE SITTING ON THE EDGE OF THE MVFR CIGS BY THE END OF THE TAF PERIOD AND AT THIS POINT...STUCK WITH VFR CONDITIONS AT BOTH LOCATIONS THROUGHOUT...THOUGH CERTAINLY SOME MVFR CIGS COULD BE SEEN AFTER 06Z. EXPECT ANOTHER ROUND OF THUNDERSTORMS TONIGHT...THOUGH WITH WARM FRONT DRIFTING NORTH...STORMS SATURDAY NIGHT SHOULD BE A BIT FARTHER NORTH OF WHERE THEY ARE NOW. BEST CHANCE FOR THUNDER LOOKS TO BE ALONG/SOUTH OF THE MN RIVER...SO INTRODUCED SOME VCTS TO THE END OF THE RWF TAF. FOR WINDS...THEY WILL BE REMARKABLY PERSISTENT THIS PERIOD OUT OF THE SOUTHEAST...WITH WINDS TODAY EXPECTED TO INCREASE TO NEAR WHAT WAS SEEN FRIDAY ACROSS MN. KMSP...CONFIDENCE HIGH IN TAF THROUGH 06Z. AFTER 06Z...MVFR CIGS THAT WILL BE SOUTHWEST OF THE FIELD WILL START TO PUSH NORTHEAST AND COULD BEGIN TO IMPACT THE FIELD. HOWEVER...STICKING WITH THE THEME OF THE GFS...WITH CIGS REMAINING ABOVE 4K FT. WILL ALSO HAVE TO WATCH HOW ACTIVITY EVOLVES TO THE SOUTHWEST LATE TONIGHT...AS THERE ARE INDICATIONS FROM THE GFS/ECMWF THAT SOME LIGHT ACTIVITY COULD APPROACH THE FIELD SUNDAY MORNING. HOWEVER...AT THIS TIME...WITH THE WARM FRONT EXPECTED DOWN ACROSS CENTRAL IOWA...FEEL BETTER SHRA/TSRA CHANCES SUNDAY MORNING WILL BE DOWN ACROSS SOUTH CENTRAL MN...SO KEPT ANY SORT OF PRECIP MENTION OUT OF THE TAF. /OUTLOOK FOR KMSP/ SUN...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS. MON...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10 KTS. TUE...CHC MVFR OR LOWER CIGS. TSRA LIKELY. WINDS SSE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
920 AM CDT SAT MAY 25 2013 .UPDATE... ISSUED AT 920 AM CDT SAT MAY 25 2013 MCS HAS BASICALLY EXITED. RADAR IS SHOWING SOME SHWRS STILL PERCOLATING FROM HLC-PHG AND DRIFTING NE TOWARD THE STATE LINE. THESE SHWRS /WITH AN OCCASIONAL RUMBLE OF THUNDER/ WERE DEVELOPING AS THE REMAINS OF THE LLJ ARE STILL LARGELY PERPENDICULAR TO THE CONVECTIVELY-REINFORCED WARM FRONT THAT EXTENDS W-E ACROSS NRN KS. EXPECT THESE SHWRS TO EVENTUALLY END. SO SHORT-TERM ADJUSTMENTS THRU NOON HAVE ADJUSTED POPS AND SKYCOVER ACCORDINGLY. 12Z LBF/OAX/TOP SOUNDINGS SUPPORT HIGH TEMPS IN THE LOW-MID 80S E OF HWY 281 AND MID-UPR 80S TO THE W. WE WILL CONT TO EVALUATE TSTM AND SVR WX POTENTIAL FOR THIS AFTN- EVE. CERTAINLY THE BOUNDARY LAID DOWN FROM THIS MCS WILL BE WATCHED CLOSELY. PLEASE FOLLOW OUR LSR/RTP/LCO PRODUCTS FOR THE IMPRESSIVE RAINFALL TOTALS OVERNGT. MANY REPORTS OF 2-3" IN A SWATH FROM SHERMAN-HALL- HAMILTON-CLAY-THAYER COUNTIES. THIS MAY SET THE STAGE FOR SOME FLOODING WITH MULTIPLE THREATS OF TSTMS THE NEXT SVRL DAYS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 423 AM CDT SAT MAY 25 2013 FOCUS REMAINS ON TSTM POTENTIAL. TSTMS CONTINUE EARLY THIS MORNING WITH MCS ROLLING EAST ACROSS CENTRAL/EASTERN NEBRASKA. MAIN IMPACT CURRENTLY FM CONVECTION IS HEAVY RAINFALL...WITH MANY LOCATIONS NORTH OF INTERSTATE 80 PICKING UP AT LEAST AN INCH OF RAIN. WE HAVE HAD ONE REPORT OF 3.13 INCHES SO FAR AT LOUP CITY WITH RAIN STILL FALLING. THIS INITIAL ROUND OF CONVECTION WILL CONTINUE TO MOVE EAST/END THIS MORNING THEN ATTENTION TURNS TO ADDITIONAL CHANCES FOR CONVECTION THIS AFTN. SFC BOUNDARY HAS SETTLED NEAR THE NEB/KS STATELINE AND FRONT IS PROGGED TO LIFT NORTHWARD THIS AFTN INTO SC NEB...WITH SFC LOW ORIENTED IN EASTERN COLORADO AND DRY LINE ALONG THE HIGH PLAINS REGION. FRONTAL BOUNDARY AND ANY RESIDUAL OUTFLOW BOUNDARIES WILL BE FOCUS FOR CONVECTION AGAIN THIS AFTN/EVE AND BOUNDARY PLACEMENT WILL NEED TO BE MONITORED CLOSELY. CAP LOOKS TO HOLD INITIALLY HOWEVER MODELS ARE INDICATING DEVELOPMENT ALONG THE DRY LINE AND ALONG/NORTH OF WARM FRONTAL BOUNDARY...AND HAVE FOLLOWED CLOSER TO RAP MODEL FOR POTENTIAL DEVELOPMENT THIS AFTN. STORMS FOR TODAY/TONIGHT HAVE THE POTENTIAL TO BE MORE VOLATILE WITH SEVERE PARAMETERS INDICATING POTENTIAL FOR SUPERCELLS. INSTABILITY IS PROGGED AROUND 4000 J/KG WITH SHEAR OF 40KTS OR SO AND STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS AND EVEN TORNADOES IN VCNTY OF BOUNDARIES. HEAVY RAINFALL/FLOODING ALSO REMAINS A CONCERN DUE TO THE HEAVY OVERNIGHT/EARLY THIS MORNING AND PRECIPITABLE WATER VALUES ARE ON THE ORDER OF AN INCH TO INCH AND A HALF AND ARE A 100 TO 150 PERCENT OF NORMAL. ALL OF THIS BEING SAID...MODELS ARE NOT CONSISTENT IN FRONTAL POSITION WHICH IS KEY TO DEVELOPMENT THIS AFTN. AGAIN FEEL RAP AND LATEST SREF RUN HAS A BETTER HANDLE ON THE FARTHER SOUTH WARM FRONTAL POSITION ACROSS OUR AREA TODAY...AND WILL NEED TO MONITOR CLOSELY. OTHERWISE...LOOK FOR SOME WARMER TEMPS THIS AFTN AND STEADY/GUSTY WINDS WITH THE HIGHEST WIND SPEEDS EXPECTED ACROSS NC KANSAS/SOUTH OF WARM FRONT...WHERE WINDY CONDITIONS ARE POSSIBLE WITH GUSTS OF 30+ MPH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 423 AM CDT SAT MAY 25 2013 SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MOST EVERY DAY AND TEMPERATURES THROUGH THE PERIOD. A VERY ACTIVE WEATHER PATTERN WILL AFFECT THE FORECAST AREA THROUGH THE PERIOD. AN UPPER LEVEL LOW DEVELOPS IN THE WESTERN CONUS AND GRADUALLY MOVES THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY FRIDAY. THIS UPPER LOW WILL SEND WAVES INTO THE FORECAST AREA THROUGH THE PERIOD. THE MODELS ARE SIMILAR IN THE MAIN FEATURES...BUT THE ECMWF HAS A LITTLE STRONGER AMPLITUDE MID WEEK. EACH OF THE WAVES WILL HAVE A CHANCE FOR SOME THUNDERSTORMS WHEN THEY MOVE THROUGH. IT CERTAINLY WILL NOT BE A RAIN OUT...IT WILL NOT RAIN ALL OF THE TIME...BUT THERE WILL BE CHANCES FOR SOME SHOWERS AND THUNDERSTORMS AT VARIOUS TIMES DURING THE PERIOD. THE BEST CHANCES FOR THUNDERSTORMS WILL BE SUNDAY AFTERNOON AND SUNDAY NIGHT...DURING WHICH TIME THE CAPE APPROACHES 5000 J/KG. ANOTHER GOOD CHANCE WILL BE MONDAY AFTERNOON AND MONDAY NIGHT WITH CAPES OVER 5000 J/KG AGAIN. BEYOND MONDAY THE MODELS HAVE A FEW TIMING DIFFERENCES WITH THE UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND THEREFORE TIMING THUNDERSTORMS IS MORE OF A CHALLENGE. TEMPERATURES WILL BE THE WARMEST SUNDAY THROUGH TUESDAY THEN SLOWLY COOL OFF TOWARD THE END OF THE WEEK. TEMPERATURES SHOULD STILL REMAIN ABOVE NORMAL FOR THIS TIME OF YEAR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 540 AM CDT SAT MAY 25 2013 TSTMS CONTINUE IN THE VICINITY OF KGRI EARLY THIS MORNING. THIS INITIAL ROUND OF CONVECTION WILL END THIS MORNING WITH REDEVELOPMENT OF STORMS FORECAST THIS AFTN AND EVENING. LOOK FOR VARIABLE WINDS TO TRANSITIION SOUTHERLY TODAY...BUT WILL BE VARIABLE/GUSTY IN VCNTY OF STORMS. CIGS/VSBYS WILL MAINLY BE VFR BUT WILL DROP TO MVFR AND POTENTIALLY NEAR IFR DURING TSTM ACTIVITY. SEVERE STORMS ARE POSSIBLE LATER TODAY/TONIGHT WITH LARGE HAIL/DAMAGING WINDS/HEAVY RAINFALL THE MAIN HAZARDS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...FAY LONG TERM...JCB AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
543 AM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 423 AM CDT SAT MAY 25 2013 FOCUS REMAINS ON TSTM POTENTIAL. TSTMS CONTINUE EARLY THIS MORNING WITH MCS ROLLING EAST ACROSS CENTRAL/EASTERN NEBRASKA. MAIN IMPACT CURRENTLY FM CONVECTION IS HEAVY RAINFALL...WITH MANY LOCATIONS NORTH OF INTERSTATE 80 PICKING UP AT LEAST AN INCH OF RAIN. WE HAVE HAD ONE REPORT OF 3.13 INCHES SO FAR AT LOUP CITY WITH RAIN STILL FALLING. THIS INITIAL ROUND OF CONVECTION WILL CONTINUE TO MOVE EAST/END THIS MORNING THEN ATTENTION TURNS TO ADDITIONAL CHANCES FOR CONVECTION THIS AFTN. SFC BOUNDARY HAS SETTLED NEAR THE NEB/KS STATELINE AND FRONT IS PROGGED TO LIFT NORTHWARD THIS AFTN INTO SC NEB...WITH SFC LOW ORIENTED IN EASTERN COLORADO AND DRY LINE ALONG THE HIGH PLAINS REGION. FRONTAL BOUNDARY AND ANY RESIDUAL OUTFLOW BOUNDARIES WILL BE FOCUS FOR CONVECTION AGAIN THIS AFTN/EVE AND BOUNDARY PLACEMENT WILL NEED TO BE MONITORED CLOSELY. CAP LOOKS TO HOLD INITIALLY HOWEVER MODELS ARE INDICATING DEVELOPMENT ALONG THE DRY LINE AND ALONG/NORTH OF WARM FRONTAL BOUNDARY...AND HAVE FOLLOWED CLOSER TO RAP MODEL FOR POTENTIAL DEVELOPMENT THIS AFTN. STORMS FOR TODAY/TONIGHT HAVE THE POTENTIAL TO BE MORE VOLATILE WITH SEVERE PARAMETERS INDICATING POTENTIAL FOR SUPERCELLS. INSTABILITY IS PROGGED AROUND 4000 J/KG WITH SHEAR OF 40KTS OR SO AND STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS AND EVEN TORNADOES IN VCNTY OF BOUNDARIES. HEAVY RAINFALL/FLOODING ALSO REMAINS A CONCERN DUE TO THE HEAVY OVERNIGHT/EARLY THIS MORNING AND PRECIPITABLE WATER VALUES ARE ON THE ORDER OF AN INCH TO INCH AND A HALF AND ARE A 100 TO 150 PERCENT OF NORMAL. ALL OF THIS BEING SAID...MODELS ARE NOT CONSISTENT IN FRONTAL POSITION WHICH IS KEY TO DEVELOPMENT THIS AFTN. AGAIN FEEL RAP AND LATEST SREF RUN HAS A BETTER HANDLE ON THE FARTHER SOUTH WARM FRONTAL POSITION ACROSS OUR AREA TODAY...AND WILL NEED TO MONITOR CLOSELY. OTHERWISE...LOOK FOR SOME WARMER TEMPS THIS AFTN AND STEADY/GUSTY WINDS WITH THE HIGHEST WIND SPEEDS EXPECTED ACROSS NC KANSAS/SOUTH OF WARM FRONT...WHERE WINDY CONDITIONS ARE POSSIBLE WITH GUSTS OF 30+ MPH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 423 AM CDT SAT MAY 25 2013 SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MOST EVERY DAY AND TEMPERATURES THROUGH THE PERIOD. A VERY ACTIVE WEATHER PATTERN WILL AFFECT THE FORECAST AREA THROUGH THE PERIOD. AN UPPER LEVEL LOW DEVELOPS IN THE WESTERN CONUS AND GRADUALLY MOVES THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY FRIDAY. THIS UPPER LOW WILL SEND WAVES INTO THE FORECAST AREA THROUGH THE PERIOD. THE MODELS ARE SIMILAR IN THE MAIN FEATURES...BUT THE ECMWF HAS A LITTLE STRONGER AMPLITUDE MID WEEK. EACH OF THE WAVES WILL HAVE A CHANCE FOR SOME THUNDERSTORMS WHEN THEY MOVE THROUGH. IT CERTAINLY WILL NOT BE A RAIN OUT...IT WILL NOT RAIN ALL OF THE TIME...BUT THERE WILL BE CHANCES FOR SOME SHOWERS AND THUNDERSTORMS AT VARIOUS TIMES DURING THE PERIOD. THE BEST CHANCES FOR THUNDERSTORMS WILL BE SUNDAY AFTERNOON AND SUNDAY NIGHT...DURING WHICH TIME THE CAPE APPROACHES 5000 J/KG. ANOTHER GOOD CHANCE WILL BE MONDAY AFTERNOON AND MONDAY NIGHT WITH CAPES OVER 5000 J/KG AGAIN. BEYOND MONDAY THE MODELS HAVE A FEW TIMING DIFFERENCES WITH THE UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND THEREFORE TIMING THUNDERSTORMS IS MORE OF A CHALLENGE. TEMPERATURES WILL BE THE WARMEST SUNDAY THROUGH TUESDAY THEN SLOWLY COOL OFF TOWARD THE END OF THE WEEK. TEMPERATURES SHOULD STILL REMAIN ABOVE NORMAL FOR THIS TIME OF YEAR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 540 AM CDT SAT MAY 25 2013 TSTMS CONTINUE IN THE VICINITY OF KGRI EARLY THIS MORNING. THIS INITIAL ROUND OF CONVECTION WILL END THIS MORNING WITH REDEVELOPMENT OF STORMS FORECAST THIS AFTN AND EVENING. LOOK FOR VARIABLE WINDS TO TRANSITIION SOUTHERLY TODAY...BUT WILL BE VARIABLE/GUSTY IN VCNTY OF STORMS. CIGS/VSBYS WILL MAINLY BE VFR BUT WILL DROP TO MVFR AND POTENTIALLY NEAR IFR DURING TSTM ACTIVITY. SEVERE STORMS ARE POSSIBLE LATER TODAY/TONIGHT WITH LARGE HAIL/DAMAGING WINDS/HEAVY RAINFALL THE MAIN HAZARDS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY LONG TERM...JCB AVIATION...FAY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
639 AM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM CDT SAT MAY 25 2013 THUNDERSTORM COMPLEX OVER NEBRASKA OVERNIGHT CONTINUES EARLY THIS MORNING. SEEING SHOWERS AND STORMS BEGINNING TO EXPAND ACROSS NORTHWEST IOWA AS WELL AS LOW LEVEL THETAE ADVECTION INCREASES. HIGH RES MODEL SUITE LOOK TO HAVE A PRETTY GOOD HANDLE ON THIS ACTIVITY. EXPECT IT TO CONTINUE THIS MORNING AND POSSIBLY EXPAND A BIT FURTHER NORTH INTO PORTIONS OF SOUTHWEST MINNESOTA. LOWERED POPS ACROSS SOUTHEAST SOUTH DAKOTA...AS ALL INDICATIONS ARE THAT THESE STORMS WILL NOT DEVELOP NORTHWEST OF THEIR CURRENT LOCATION. MOST OF THE STORMS SHOULD BE EAST OF THE CWA BY 16Z. MAIN IMPACTS WILL BE BRIEFLY HEAVY RAIN AND POSSIBLY SMALL HAIL WITH THESE CELLS...AS EFFECTIVE SHEAR AND CAPE ARE TOO LOW FOR ANY SEVERE THREAT. MUCH OF THE AFTERNOON SHOULD THEN BE DRY ACROSS THE CWA WITH AN AREA OF SUBSIDENCE LIKELY BEHIND THIS MORNINGS SHORTWAVE. WARM FRONTAL BOUNDARY WILL POSITION ITSELF SOUTH OF THE MISSOURI RIVER THIS AFTERNOON. HRRR AND RAP TRY TO BREAK THE CAP THEIR THIS AFTERNOON...BUT BOTH THESE MODELS SEEM A BIT OVERDONE WITH DEWPOINTS AND INSTABILITY. FEEL MORE LIKELY SCENARIO IS ACTIVITY WAITS FOR THE LOW LEVEL JET TO KICK IN AFTER 0Z BEFORE IT GETS GOING. OTHER ISSUE TODAY IS CLOUD COVER AND HIGH TEMPERATURES. INTERESTINGLY THE HRRR AND RAP ARE COMPLETE OPPOSITE OF EACH OTHER...GIVING AROUND A 20 DEGREE DIFFERENCE IN HIGHS...WITH THE RAP HAVING MORE STRATUS AND COOLER TEMPERATURES. THE GEM AND ECMWF SIDE CLOSER TO THE RAP...WITH THE NAM IN BETWEEN. SINCE THE AREAL COVERAGE OF LOW STRATUS IS CURRENTLY LESS THAN EXPECTED...DID GO AHEAD AND RAISE HIGHS SEVERAL DEGREES FOR TODAY IN OUR CENTRAL AND WEST. ALSO THE HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION...SO ONE WOULD THINK ITS SHORT RANGE FORECAST SHOULD BE SOMEWHAT RELIABLE...AND IT HAS CONSISTENTLY BEEN WARM FOR TODAY. LOWERED HIGHS A FEW IN THE EAST WHERE IT IS RAINING...AND WHERE STRATUS SHOULD INDEED HOLD IN FOR MUCH OF THE DAY. AGAIN THIS IS A PRETTY LOW CONFIDENCE TEMPERATURE FORECAST FOR ANYWHERE EAST OF THE JAMES RIVER. BUT FEEL GOING FORECAST IS A DECENT STARTING POINT...WITH THE DAY SHIFT LIKELY HAVING TO ADJUST UP OR DOWN DEPENDING ON CLOUD COVER TRENDS. QUIET SHORT TERM CONDITIONS FROM THE AFTERNOON HOURS SHOULD TURN QUICKLY TO MORE STORMY CONDITIONS OVERNIGHT. GAVE A FAIR AMOUNT OF CREDIT TO THE CONSISTENCY OF THE 00Z HIGH RESOLUTION NAMDNG5 AND WRF-ARW SOLUTIONS...WHICH FIT THE OVERALL CONCEPTUAL MODEL FOR CONVECTIVE INITIATION TONIGHT. BOUNDARY FROM CURRENT NIGHT MCS WILL BE FESTERING AND DRIFTING NORTHWARD...WITH LIKELY 1000 TO 1500 J/KG ELEVATED CAPE LIFTED FROM 1 TO 1.5 KM AGL. AS 35 TO 40 KNOT LOW LEVEL JET DEVELOPS TONIGHT THROUGH THE CENTRAL PLAINS... SHOULD BECOME ENOUGH TO INITIATE ELEVATED THUNDERSTORMS NEAR/NORTH OF THE BOUNDARY WHICH WILL BE DRIFTING NORTHWARD OF INTERSTATE 80 DURING THE EVENING HOURS. EFFECTIVE SHEAR IN AREAS NORTH OF THE BOUNDARY WILL BE VERY CONCENTRATED IN THE 1-3KM LAYER WITH STRONGEST WINDS IN LOW LEVELS AND WEAKENING MID LEVEL WINDS ROUGHLY 20-30 KNOTS...WITH LESSER DEEP LAYER SHEAR CONTRIBUTIONS FROM ABOVE. ALL SUGGEST AT LEAST A MINIMAL THREAT FOR ISOLATED LARGER HAIL OR DAMAGING WINDS THROUGH THE MISSOURI RIVER CORRIDOR AND LIFTING SOMEWHAT NORTHWARD THROUGH 066-08Z. OTHER SIGNIFICANT CONVECTIVE INITIATION IS LIKELY TO OCCUR BACK THROUGH THE WESTERN HIGH PLAINS WHERE STRONGER SHEAR EXISTS WITH A BIT STRONGER MID LEVEL WINDS TO AROUND 25 KNOTS...AS WELL AS THE DEEP UPSLOPE TRANSPORT OF MOISTURE TO RESULT IN STRONGER INSTABILITY. EVENTUALLY...WHEN SUPERCELL MOTIONS WHICH WILL TAKE ACTION MORE SOUTHWARD THAN EAST START TO EASE...AND LOW LEVEL JET VEERS EASTWARD...WILL FIND A MORE LINEAR MCS LIKELY TAKING SHAPE. MANY HI RES MODELS SUGGEST THIS MCS WILL ZIPPER DOWN THE LOCATION OF THE WARM ADVECTION WING SPREADING NORTHWARD...MOVING TOWARD EAST CENTRAL SD AND SOUTHWEST MN LATE NIGHT. SEVERE THREAT WITH THIS FEATURE WOULD SEEM TO BE SOMEWHAT LOWER...BUT LIKELY TO GET SOME GUSTY WINDS AND AREAS OF HEAVY RAINFALL. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 430 AM CDT SAT MAY 25 2013 MCS EXPECTED TO WEAKEN AND SHIFT EAST ON SUNDAY...AND WITH MID LEVEL FORCING SHOWING TENDENCY TO FORCE SUBSIDENCE AROUND MIDDAY...AGAIN EXPECT THAT MUCH OF THE DAYTIME PERIOD WILL PROBABLY END UP PRECIPITATION FREE. HOWEVER...CLOUDS LIKELY TO PERSIST WITH STRATUS DEVELOPING IN WAKE OF SYSTEM. MOST LIKELY TO GET BREAKS THROUGH THE WESTERN AND SOUTHERN CWA DURING THE AFTERNOON...AND HAVE PUSHED EXPECTED TEMPS TO NEAR 80 THERE... WHILE MORE MID TO UPPER 60S LINGER IN THE FAR EAST. RESULT OF THIS WILL BE GENERATION OF DECENT POTENTIAL INSTABILITY OF 1500-2000 J/KG ACROSS THE AREA...WITH WEAKEST OF THE CAPPING INVERSION NEAR THE MISSOURI RIVER CORRIDOR. SHEAR BECOMES A BIT MORE DISTRIBUTED THROUGH THE EFFECTIVE LAYER...AND FAIRLY CLOSE TO THOSE VALUES FROM THIS EVENING FROM 30 TO 35 KNOTS. A FEW MORE SEVERE STORMS WOULD BE POSSIBLE MAINLY THROUGH THE SOUTHWEST HALF OF THE AREA DURING THE LATER AFTERNOON AND EVENING HOURS...AS INITIATION LIKELY TO BE A RESULT OF WEAK IMPULSE SLIDING UP BACK SIDE OF RIDGE IN THE LATER AFTERNOON AND EARLY EVENING. THE FURTHER ONE GOES INTO THE FORECAST...THE LESS RELIABLE ANY GUIDANCE BECOMES GIVEN THE ABUNDANCE OF CONVECTION...AND THE INCREASINGLY GREAT UNCERTAINTY AS TO WHERE CRITICAL BOUNDARIES MAY LIE. ONE THING FOR SURE...GIVEN THE CLOSED LOW ACROSS THE WESTERN U.S. AND THE SOUTHWEST FLOW ALOFT...DIFFICULT TO PINPOINT ANY TIME FROM MONDAY ON THAT ONE COULD SAY THERE WAS ABSOLUTELY NO CHANCE FOR PRECIPITATION...BUT ON THE SAME FRONT IT CERTAINLY WILL NOT BE AN ALL TIME WASHOUT WITH MANY BREAKS DEFINED ON THE MESOSCALE. MEMORIAL DAY AND MONDAY NIGHT WILL PLACE THE AREA ON THE SOUTHERN FLANK OF A COUPLE OF WAVES MOVING OVER THE RIDGE...SO LIKELY TO HAVE ENHANCEMENT OF PRECIPITATION IN THE NOCTURNALLY FAVORED PERIODS. WHILE A FEW SEVERE STORMS ARE AGAIN WELL WITHIN REASON...HIGH PRECIPITABLE WATER AND FAIRLY SLOW MOVING WIND PROFILES BRING THE CONCERN OF AREAS OF HEAVY RAINFALL...AT THIS RANGE HARD TO DEFINE. AT THE MOMENT...THE PROSPECT FOR MORE SIGNIFICANT CONVECTION AND SEVERE WEATHER WOULD APPEAR TO BE LATE DAY WEDNESDAY INTO THURSDAY...AS DEEP WESTERN CLOSED LOW KICKS STRONGER JET ENERGY INTO THE PLAINS. MOISTURE THROUGH LOWER LEVELS /THUS INSTABILITY/ WILL CONTINUE TO BENEFIT FROM PERSISTENT SOUTHERLY FLOW. TEMPERATURES WILL LIKELY GRAVITATE TO SOMEWHAT ABOVE NORMAL READINGS THROUGH THE UPCOMING WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 619 AM CDT SAT MAY 25 2013 LOW CONFIDENCE TAF FORECAST. MANY GUIDANCE SOLUTIONS SHOWING IFR TO MVFR STRATUS THIS MORNING. THESE SOLUTIONS SHOW IT DEVELOPING OVER NEBRASKA AND IOWA AND ADVECTING INTO OUR AREA. WINDS ARE SOUTHEASTERLY FROM 1500 FEET AND BELOW AND SOUTHWESTERLY ABOVE THAT. THAT SOUTHWESTERLY WIND IS ADVECTING IN DRY AIR...THUS ONLY STRATUS BELOW 1500 FEET WOULD BE ABLE TO ADVECT INTO THE AREA. CURRENTLY NOT SEEING MUCH OF THAT OUT THERE. THUS CUT BACK ON THE LOW CIGS AND KEPT MOST OF OUR AREA VFR. HOWEVER WILL HAVE TO MONITOR THINGS THROUGH THE MORNING. NOT OUT OF THE QUESTION THAT LOW STRATUS STILL FORMS...OR THAT WE GET SOME MVFR STRATOCU AFTER SUNRISE. NEXT PROBLEM IS CONVECTION. THIS MORNINGS ACTIVITY SHOULD REMAIN EAST OF THE TAF SITES AND EXIT THE CWA BY MID TO LATE MORNING. TONIGHT...EXPECT ACTIVITY TO GET GOING IN THE VICINITY OF A LOW LEVEL WARM FRONT AFTER 03Z. WHERE THIS EXACTLY HAPPENS REMAINS UNCERTAIN. AT THIS POINT IT APPEAR THAT AREAS NEAR THE MISSOURI RIVER HAVE THE BEST SHOT. ALSO EXPECT A THUNDERSTORM COMPLEX TO FORM TO OUR NORTHWEST...AND DIVE THROUGH THE AREA AFTER 7Z INTO THE MORNING HOURS. MAIN THREATS WILL BE REDUCTIONS TO IFR VIS/CIG IN THE HEAVIER RAIN...BUT SOME HAIL AND GUSTY WINDS ARE ALSO POSSIBLE. STRATUS MAY ALSO TRY TO FORM TONIGHT...BUT THAT WILL BE DEPENDENT ON HOW WELL WE MIX OUT THE LOW LEVEL MOISTURE TODAY. DID PUT MVFR CIGS IN THE TAFS STARTING THIS EVENING...BUT THIS IS ALSO UNFORTUNATELY UNCERTAIN. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN/CHENARD LONG TERM...CHAPMAN AVIATION...CHENARD
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
631 AM CDT SAT MAY 25 2013 .AVIATION... THE WEAK UPPER LOW OVER THE REGION WILL AGAIN RESULT IN AREAS OF SHRA/TSRA THROUGHOUT THE DAY. RADAR MOSAIC SHOWS THIS ACTIVITY CURRENTLY FROM THE KAUS/KSAT AREA NORTHWARD TO THE RED RIVER. AS THE DAY PROGRESSES EXPECT CONVECTION TO INCREASE IN COVERAGE WITH SOME AFFECTING THE TAF SITES MAINLY THIS AFTERNOON. AS THE UPPER LOW MOVES FARTHER NORTHEAST TONIGHT...SOME ACTIVITY WILL LINGER OVER THE AREA BUT IT SHOULD BE MOSTLY -RA AFTER 26/03Z. AIRPORT OPERATIONS WILL BE AFFECTED BY LIGHTNING STRIKES...WET RUNWAYS AND REDUCTIONS IN CIGS AND VIS DURING CONVECTION. KDFW OPERATIONS SHOULD EXPECT AN AIRPORT WEATHER WARNING TO BE ISSUED LATER TODAY AS LIGHTNING NEARS THE AIRPORT. FOR THIS TAF CYCLE...MVFR CIGS ARE ON GOING AT KACT BUT THEY SHOULD ARRIVE AT THE METROPLEX AIRPORTS 13-14Z. CIGS WILL LIFT TO VFR BY LATE MORNING. MVFR CIGS WILL RETURN TO KDFW LATE TONIGHT AROUND 26/09Z AND SHOULD END AROUND 26/16Z. 75 && .PREV DISCUSSION... /ISSUED 347 AM CDT SAT MAY 25 2013/ RADAR/SATELLITE LOOP INDICATES THAT THE WEAK MID LEVEL LOW IS LIKELY LOCATED NEAR ABILENE AND 00Z 500MB ANALYSIS CONFIRMS IT IS WARM-CORE IN NATURE. AS IS OFTEN THE CASE WITH WARM-CORE LOWS...CONVECTION IS FIRING BEFORE SUNRISE ACROSS THE HILL COUNTRY WITHIN A WEAK LOW LEVEL JET AXIS WHERE THETA-E ADVECTION AND OROGRAPHIC LIFT ARE OCCURRING. SHORT-TERM MODELS SUCH AS THE HRRR AND RUC SUGGEST THAT SCATTERED CONVECTION WILL CONTINUE TO EXPAND NORTHWARD FROM CENTRAL TEXAS INTO THE WESTERN ZONES DURING THE MORNING HOURS. THE GFS APPEARS TO BE SUFFERING FROM GRID SCALE CONVECTIVE FEEDBACK WHICH IS RESULTING IN VERY HIGH QPF AND CONTAMINATED MASS FIELDS...THUS THE GFS WILL NOT BE USED IN THE SHORT-TERM. THE NAM SEEMS TO BE MATCHING CURRENT TRENDS AND SHORT- TERM MODELS WELL AND THEREFORE IT GIVES CONFIDENCE TO RAISE POPS TODAY. WE EXPECT THE BEST COVERAGE OF CONVECTION IN THE WESTERN ZONES THIS MORNING. SCATTERED CONVECTION WILL BUILD/EXPAND EASTWARD INTO THE EASTERN ZONES DURING THE MIDDAY/AFTERNOON HOURS. THE AIRMASS OVER THE EASTERN ZONES WILL BE A BIT MORE UNSTABLE DUE TO BETTER INSOLATION AND A COUPLE OF STRONG STORMS WITH GUSTY WINDS WILL BE POSSIBLE...BUT DUE TO WEAK SHEAR THE SEVERE THREAT IS LOW. HIGHS TODAY IN THE WESTERN ZONES WILL ONLY BE IN THE UPPER 70S TO LOW 80S DUE TO CLOUDS/RAIN...WITH HIGHS IN THE EASTERN ZONES REACHING THE MID 80S. SCATTERED CONVECTION WILL CONTINUE INTO THE EVENING HOURS BEFORE DISSIPATING WITH LOSS OF HEATING. THE WARM CORE MID LEVEL LOW WILL BE EXITING THE REGION TO THE NORTHEAST TONIGHT...AND THEREFORE THE RAIN CHANCES WILL COME TO AN END. EXPECT A DRY SUNDAY WITH TEMPERATURES REBOUNDING INTO THE MID-UPPER 80S AREA WIDE. AS AN UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTER-MOUNTAIN WEST...A SURFACE LOW WILL DEEPEN IN THE HIGH PLAINS MONDAY. THIS WILL BRING BREEZY SOUTH WINDS TO THE REGION MONDAY WHICH WILL LIKELY PERSIST THROUGH THE WEEK. LOW TEMPS WILL WARM INTO THE 70S AREA WIDE BY MIDWEEK WITH HIGHS GENERALLY IN THE MID 80S EAST TO LOW 90S WEST. THE SOUTHWEST FLOW ABOVE THE SURFACE WILL BRING A THERMAL INVERSION INTO THE AREA. THUS THE FORECAST LOOKS DRY UNLESS/UNTIL FORCING ARRIVES TO WEAKEN THE CAP. MODEL GUIDANCE REMAINS IN POOR TO FAIR AGREEMENT REGARDING THE EVOLUTION/EJECTION OF THE WEST COAST UPPER TROUGH MID-LATE WEEK. THE ECMWF CONTINUES TO SHOW A VERY NEGATIVELY TILTED TROUGH SWINGING THROUGH THE REGION LATE WEDNESDAY AND THURSDAY WHICH WOULD BODE WELL FOR RAIN. BUT IT CONTINUES TO BE THE ONLY MODEL THAT SHOWS THE TROUGH EJECTION LIKE THIS...AND FRANKLY THE 500MB PATTERN IT PRESENTS JUST DOES NOT LOOK REALISTIC. IF IT WERE NOT FOR THE ECMWF BEING THE BETTER OF THE LONG RANGE MODELS...I WOULD DISCOUNT IT ALTOGETHER AND SHOW A DRY FORECAST ON THURSDAY...BUT FOR NOW HAVE RETAINED THE SLIGHT CHANCE POPS. THE GFS/UKMET/GEM FORECASTS SHOW THAT THE UPPER ENERGY NEEDED TO BREAK THE CAP WILL LIKELY REMAIN WELL NORTHWEST OF THE REGION. FURTHERMORE...THE DRYLINE ALSO LOOKS LIKE IT WILL REMAIN TOO FAR TO THE WEST...WITH THE GFS SHOWING IT AS FAR WEST AS THE TX PANHANDLE. STORM MOTIONS WILL GENERALLY BE NORTHEAST AND THIS MEANS STORMS WOULD NOT EVEN HAVE A CHANCE TO PROPAGATE INTO THE CWA EITHER. SO IN SUMMARY THE RAIN CHANCES ON THURSDAY AT THIS POINT ARE HINGING ON THE ECMWF BEING CORRECT...AND THIS MAY BE A BIT OF A LONG SHOT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 84 69 87 69 87 / 40 30 10 5 0 WACO, TX 83 68 87 68 89 / 50 30 10 5 0 PARIS, TX 83 67 85 66 85 / 30 30 10 5 0 DENTON, TX 84 67 86 68 87 / 40 30 10 5 0 MCKINNEY, TX 84 67 85 68 87 / 30 30 10 5 0 DALLAS, TX 85 71 87 70 89 / 30 30 10 5 0 TERRELL, TX 84 67 86 68 88 / 30 30 10 5 0 CORSICANA, TX 84 67 88 68 89 / 30 30 10 5 0 TEMPLE, TX 82 67 87 68 88 / 50 20 10 5 0 MINERAL WELLS, TX 81 66 87 67 89 / 40 20 10 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 75/
AREA FORECAST DISCUSSION
NWS SPOKANE WA
833 AM PDT Sat May 25 2013 .SYNOPSIS... Memorial Day Weekend is expected to be a little cooler than average, and a series of weak upper level disturbances will bring the potential for scattered showers Sunday and Monday. The moist, showery weather pattern is expected to linger into late next week. && .DISCUSSION... Update: Satellite imagery from this morning shows two closed lows...one near the north Washington coast and another over southern Alberta. Models show these two features moving very little today. With no strong forcing mechanism to generate showers...there should be less shower activity today compared to yesterday. The 13z HRRR model shows most of the showers today will be along the East Slopes of the Cascades and north of the Columbia Basin over the northern mountains. This make sense given these areas are in closest proximity to the two aforementioned lows...and that showers are more likely to develop over the mountainous terrain. Forecast has this part of the forecast well handled with only change to lower mountain pops to 20 percent through the morning with better chances holding off til afternoon when instability increases. Latest SREF and SPC guidance, as well as the 13z HRRR model shows minimal thunder chances today. The better chances will be north of the Canadian border...and over the Clearwaters. With cloud cover this morning extensive over the Idaho Panhandle and northeast Washington mountains...this will further lower convective potential. Cloud cover was increased this morning over North Idaho, and thunder was removed from the northern mountains, but a slight chance was kept for the Camas Prairie with this area on the edge of the best convective potential. Also lowered high temperatures today a few degrees for Sandpoint and Kellogg. JW && .AVIATION... 12Z TAFS: General trof over Eastern Washington and Northern Idaho continues through this interval. Some late night and early morning valley fog primarily in northern valleys with some showers at times...primarily in the afternoon and early evening. VFR ceilings and visibilities are expected to prevail through the 24 hour interval. /Pelatti && .PRELIMINARY POINT TEMPS/POPS... Spokane 63 44 65 46 65 47 / 20 10 30 40 30 10 Coeur d`Alene 63 42 65 45 64 44 / 20 20 30 40 40 10 Pullman 64 43 63 44 65 46 / 10 10 30 40 20 20 Lewiston 71 48 70 50 71 51 / 10 10 30 40 20 20 Colville 67 41 72 45 69 44 / 40 30 20 20 50 20 Sandpoint 61 39 66 43 63 42 / 30 20 20 40 50 20 Kellogg 59 44 63 46 62 47 / 40 20 30 50 50 20 Moses Lake 72 46 73 49 73 50 / 10 10 30 20 10 20 Wenatchee 68 47 70 49 71 51 / 10 10 30 10 10 20 Omak 68 41 71 45 70 46 / 30 20 30 10 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
427 AM PDT Sat May 25 2013 .SYNOPSIS... Memorial Day Weekend is expected to be a little cooler than average, and a series of weak upper level disturbances will bring the potential for scattered showers Sunday and Monday. The moist, showery weather pattern is expected to linger into late next week. && .DISCUSSION... Today through Sunday...General trof pattern continues to influence the sensible weather over Eastern Washington and Northern Idaho keeping it unsettled at times along with temperatures on the cool side of what would be considered normal this time of year. Last few HRRR model runs hit at surface based convection over the northern mountains after 11AM PDT today and upon further inspection GFS runs for this interval show the cold pool aloft at 500mb helping to keep the instability overhead extends west to overhang parts of the cascades...thus the minor mention of afternoon and early evening thunderstorms has been stretched westward to cover parts of the East Slopes of the Northern cascades roughly north of Leavenworth. Models also hint at a mesoscale shortwave or two producing enough forcing to allow for some minor mention of showers overnight...one near the cascades and the other passing over the Blue Mountains up into North Idaho Panhandle. Sunday the trof overhead is very very cluttered with synoptic and mesoscale shortwave propagation through it which allows for the mention of showers to persist. Forecast temps show a very slight cooling trend as the flow turns a bit more southerly, which is a warm trajectory most of the time, for Sunday. Additionally since the jet stream is south of the forecast area through this time interval resulting in a lowered tropopause (down to near 400mb) some of these showers could produce the typical early spring precipitation type (graupel or soft hail) for a spell along with mixing moderate wind gusts down to the surface which is something to keep in mind over the weekend. /Pelatti Sunday Night through Wednesday: The cool upper level trough that has been anchored over the Pacific Northwest since Wednesday is expected to pivot into western Montana Sunday night into Monday bringing scattered showers to the eastern third of Washington and northern Idaho. Despite the displacement of this upper low, our weather pattern isn`t expected to change much. There is good agreement between the medium range models that the Polar Jet will dive into southern Oregon and carve another upper level trough over the Pacific Northwest. The best jet dynamics (Q-Vector Divergence) Monday night into Tuesday should be over southern Oregon into the Great Basin, but there will be enough moisture and deep layer instability with the weakening frontal occlusion to maintain a good chance of showers Tuesday and Tuesday night. Depending on the timing of this system, we may need to add a mention of thunderstorms on Tuesday. The 00z GFS, Canadian and ECMWF are in pretty good agreement with a weak, negatively tilted trough over central and western Washington. The GFS and ECMWF are producing precipitation that looks convectively driven over the north Cascades. The potential for thunderstorms over the burn scars around Wenatchee, Ellensburg, and Chelan will be a concern through the summer and we will continue to monitor patterns like this one closely for mudslides and debris flows. The axis of a west to east oriented upper trough is expected to linger over the Pacific Northwest Wednesday and through the end of the week. It does look like Tuesday`s frontal occlusion will bring the most widespread shower activity to the region this week, but afternoon and early evening showers will be in the forecast for much of the week. /GKoch Wednesday Night through Friday Night: Through this time frame we continue to see an unsettled pattern that will continue to feature the chance for precipitation across most of the Inland NW especially for the higher terrains of the ID Panhandle along with Cascade Crests earlier in the period. Models are in pretty good agreement through Friday Afternoon by keeping a large scale negatively tilted trough pattern in place allowing for moisture to flow in behind the low center that pushes to our SE throughout the night on Wednesday. With the increased moisture, there will be thick cloud cover keeping temps in the lower 60s and 70s for most correlating to below normal temps for this time of year. Low temps will follow the same pattern of a couple degrees below normal due to the lack of daytime heating. Towards the end of the period models are indicating a ridge builds behind the exiting trough which should help to diminish the precipitation threat...lower the cloud coverage and ultimately push temperatures closer to seasonal averages as we approach next weekend. Overall not many changes were made to the forecast..just tinkered with the POPs slightly to reflect most recent model data and trended the temps in the same manner. /Fliehman && .AVIATION... 12Z TAFS: General trof over Eastern Washington and Northern Idaho continues through this interval. Some late night and early morning valley fog primarily in northern valleys with some showers at times...primarily in the afternoon and early evening. VFR ceilings and visibilities are expected to pravail through the 24 hour interval. /Pelatti && .PRELIMINARY POINT TEMPS/POPS... Spokane 63 44 65 46 65 47 / 20 10 30 50 30 10 Coeur d`Alene 63 42 65 45 64 44 / 20 20 30 50 40 10 Pullman 64 43 63 44 65 46 / 10 10 30 50 20 20 Lewiston 71 48 70 50 71 51 / 10 10 30 50 20 20 Colville 67 41 72 45 69 44 / 40 30 20 20 50 20 Sandpoint 63 39 66 43 63 42 / 30 20 20 40 50 20 Kellogg 61 44 63 46 62 47 / 40 20 30 60 50 20 Moses Lake 72 46 73 49 73 50 / 10 10 30 20 10 20 Wenatchee 68 47 70 49 71 51 / 10 10 30 10 10 20 Omak 68 41 71 45 70 46 / 30 20 30 10 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
302 PM MDT SAT MAY 25 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 301 PM MDT SAT MAY 25 2013 ...FIRE WEATHER CONCERNS CONTINUE ACROSS THE MTS...AND INCREASE ACROSS THE SOUTHERN PLAINS ON SUNDAY.. DEEPENING SFC LOW IN VCNTY OF KLHX HAS SPREAD SOME GUSTY SOUTHWEST WINDS ACROSS THE MOUNTAINS AND SOUTHERN PORTIONS OF THE SE PLAINS. AS OF 20Z...SFC DRY LINE IS LOCATED ALONG A LINE FROM JUST EAST OF KLAA...TO NEAR KSPD. TO THE WEST OF THIS LINE...DEW POINTS HAVE BEEN DROPPING INTO THE SINGLE DIGITS...TEENS AND EVEN SOME NEGATIVE READINGS ACROSS THE MOUNTAINS. TO THE EAST OF THE DRY LINE...DEW POINTS ARE STILL IN THE UPPER 40S TO LOWER 50S. LATEST HRRR STILL PUSHES THE DRY LINE INTO WESTERN KS BY 22Z...WITH DEW POINTS DROPPING INTO THE 30S ALONG THE EASTERN BORDER. STILL CONCERNED THAT SOME INITIAL CONVECTION MAY FIRE ALONG THE DRY LINE LATE THIS AFTERNOON...SO WILL MAINTAIN SOME ISOLATED POPS OUT THAT WAY. MOST OF IT WILL BE HIGH BASED...WITH GUSTY WINDS AND LIGHTNING THE MOST LIKELY THREATS. COULDN`T RULE OUT SOME MARGINAL SEVERE HAIL AND WIND GUSTS NEAR THE CO/KS BORDER IF CAPES CAN STAY UP HIGH ENOUGH. SPC HAS UPDATED THE LATEST OUTLOOK TO INCLUDE EASTERN KIOWA...PROWERS...AND BACA COUNTIES. INITIALLY 0-6 KM SHEAR VALUES ARE AROUND 20-30 KTS WHICH IS MARGINAL FOR SEVERE...BUT THESE VALUES DO INCREASE INTO THE EVENING...SO THIS AREA WILL NEED TO BE MONITORED. EXPECT CONVECTION TO SHIFT QUICKLY EASTWARD INTO KS THROUGH THE LATE AFTN/EARLY EVENING...THOUGH OUTFLOWS MAY AID WESTWARD RETREAT OF THE DRY LINE. OVERNIGHT...DRY LINE PROGRESSES BACK WESTWARD BEFORE MIXING BACK EASTWARD DURING THE DAY ON SUNDAY AS AN UPPER JET IN SOUTHWEST FLOW ALOFT MOVES ACROSS THE AREA. CURRENT FIRE WEATHER WATCH WILL BE UPGRADED TO A RED FLAG WARNING WITH THE AFTERNOON PACKAGE AS ALL AREAS LOOK TO MEET CRITICAL FIRE WEATHER CONDITIONS. SFC BOUNDARY HANGS UP JUST NORTH OF THE AREA AND WITH DRY LINE EXPECTED TO PUSH INTO WESTERN KS DURING THE AFTERNOON...WILL GO WITH NIL POPS FOR THE ENTIRE CWA. LOOKS LIKE HIGHS TOMORROW SHOULD STAY AROUND 3-5 DEGREES BELOW RECORDS (COS 90...2012 PUB 97...2012 ALS 84...1969)...THOUGH STILL WAY ABOVE CLIMATOLOGICAL AVERAGES. -KT .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 301 PM MDT SAT MAY 25 2013 SUNDAY NIGHT-MONDAY NIGHT...MODERATE WARM AND DRY SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE REGION AS A BROAD UPPER TROUGH SLOWLY DIGS ACROSS THE PAC NORTHWEST AND INTO THE GREAT BASIN. MODELS CONTINUE TO INDICATE A WEAK EMBEDDED SHORT WAVE TRANSLATING ACROSS THE ROCKIES SUNDAY NIGHT WITH ANOTHER MINOR WAVE MOVING ACROSS THE STATE LATE MONDAY AFTERNOON. FIRST WAVE SENDS A WEAK BACKDOOR COLD FRONT ACROSS EASTERN COLORADO EARLY MONDAY MORNING BEFORE FRONT MIXES OUT THROUGH THE EARLY AFTERNOON. MODELS ALSO INDICATING INCREASING MID AND HIGH LEVEL MOISTURE ASSOCIATED WITH SECOND WAVE SPREADING ACROSS THE AREA THROUGH THE DAY ON MONDAY...WHICH LOOKS TO LIMIT STRONGER WINDS ALOFT FROM MIXING DOWN THROUGH THE AFTERNOON. AT ANY RATE...COULD SEE BRIEF RED FLAG CONDITIONS DEVELOPING ACROSS THE EASTERN MTS LATE MONDAY AFTERNOON...BUT LOOKS TO BE TOO MARGINAL TO ISSUE ANY HIGHLIGHTS AT THIS TIME. WITH THE PASSING WAVES...COULD SEE SOME HIGH BASED CONVECTION MONDAY AFTERNOON AND EARLY EVENING ACROSS MAINLY THE CENTRAL AND EASTERN MTS WITH HIGHS EXPECTED TO BE ONLY SLIGHTLY COOLER THAN SUNDAY. TUESDAY-THURSDAY NIGHT...FIRE DANGER EXPECTED TO INCREASE ACROSS SOUTHERN COLORADO AS GREAT BASIN UPPER TROUGH SLOWLY LIFTS OUT ACROSS THE NORTHERN ROCKIES THROUGH THE PERIOD. INCREASING SOUTH TO SOUTHWEST FLOW ACROSS THE AREA TUESDAY DEVELOPS A LA JUNTA LOW TUESDAY AFTERNOON SUPPORTING THE POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS ACROSS THE SOUTHERN MTS AND ADJACENT PLAINS AS WELL AS ACROSS THE FAR SOUTHEAST PLAINS...WITH SOME MORE HIGH BASED STORMS POSSIBLE ACROSS THE CENTRAL MTS AND SOUTHWEST MTS. MORE WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS LOOK TO BE POSSIBLE ACROSS SOUTHERN COLORADO WEDNESDAY AND THURSDAY WITH BREEZY TO WINDY WEST TO SOUTHWEST FLOW ALOFT. PASSING TROUGH KEEPS CHANCE AND SLIGHT CHANCES OF THUNDERSTORMS ACROSS THE AREA TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WITH BEST CHANCES ACROSS NORTHERN PORTIONS OF THE AREA. MODELS KEEP BEST LOW LEVEL MOISTURE WELL INTO WESTERN KANSAS THOUGH LATEST ECMWF IS A TAD FURTHER WEST WITH DRY LINE WEDNESDAY AFTERNOON AND WILL NEED TO MONITOR FOR POSSIBLE STORMS ACROSS THE FAR SE PLAINS. AS FOR TEMPS...SHOULD SEE HIGHS FALLING BACK TO AROUND SEASONAL AVERAGES THROUGH THE PERIOD WITH COOLING ALOFT. FRIDAY-SATURDAY...COOL AND DRY NORTHWEST FLOW PROGGED TO DEVELOP BEHIND PASSING TROUGH...KEEPING SLIGHT POPS DIURNAL POPS IN PLACE ACROSS THE HIGH TERRAIN ALONG WITH TEMPERATURES SLIGHTLY BELOW AVERAGE INTO THE EARLY WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 301 PM MDT SAT MAY 25 2013 VFR CONDITIONS EXPECTED AT TAF SITES WITH BREEZY SOUTH TO SOUTHWEST WINDS GUSTING TO 25-30 KTS DECREASING TOWARDS 02Z. SHOULD SEE LIGHT DIURNALLY DRIVEN WINDS OVERNIGHT...WITH BREEZY SOUTHWEST WINDS RETURNING FOR THE TAF SITES SUNDAY AFTERNOON. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ221-222-225- 227. RED FLAG WARNING FROM 11 AM TO 9 PM MDT SUNDAY FOR COZ221-222- 225-227-233-237. && $$ SHORT TERM...KT LONG TERM...MW AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1105 AM MDT SAT MAY 25 2013 .UPDATE... ISSUED AT 1009 AM MDT SAT MAY 25 2013 WINDS HAVE ALREADY BEEN QUITE GUSTY ACROSS SOUTHERN PORTIONS OF THE SOUTHEAST PLAINS AND SOME MOUNTAIN AREAS THIS MORNING...AND IS FORECAST TO SPREAD INTO MOST OF THE LOWER ELEVATIONS BY THIS AFTERNOON. WHERE FUELS ARE CRITICAL THIS WILL RESULT IN HIGH FIRE DANGER. MAIN CHANGE TO THE GRIDS WAS TO DROP SFC DEW POINTS ACROSS THE MTS/I-25 CORRIDOR AS YESTERDAY THEY DROPPED INTO THE SINGLE DIGITS AND LOWER TEENS AND SEE NO REASON WHY THEY WON`T DO THE SAME TODAY. HRRR SEEMS TO HAVE LATCHED ON TO THIS WELL AND HAVE USED THESE GRIDS TO BLEND TOWARDS. SHORT RANGE HIGH RES MODELS POINT TO BEST POTENTIAL FOR THUNDERSTORMS ALONG THE CO/KS BORDER DURING THE LATE AFTERNOON. HAVE TRIMMED BACK WESTERN EXTENT OF POPS TO BETTER REFLECT THIS. LOOKS LIKE PORTIONS OF EASTERN LAS ANIMAS AND WESTERN BACA COUNTY COULD SEE AN HOUR OR TWO OF CRITICAL TO NEAR CRITICAL FIRE WEATHER CONDITIONS THIS AFTERNOON. HOWEVER DRY LINE SHOULD WAVER BACK WESTWARD INTO BACA COUNTY EARLY THIS EVENING AS CONVECTION FIRES ALONG THE DRY LINE. WINDS ALSO APPEAR TO SLACKEN OFF SOME ACROSS EASTERN LAS ANIMAS COUNTY AS THE SFC TROF DEEPENS AND BEST GRADIENT SHIFTS SOUTH AND EASTWARD. THUS WILL HOLD OFF ON FIRE WEATHER HIGHLIGHTS FOR THESE AREAS. -KT && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 440 AM MDT SAT MAY 25 2013 ...HOT... JULY-LIKE WX EXPECTED TODAY AS DRY SW WINDS ALOFT CONTINUE TO OVERSPREAD THE AREA...AND PRECIP REMAINS MOSTLY OUTSIDE OUR CWA. H7 TEMPS RISE ANOTHER DEGREE OR SO...AND AFTER GETTING BURNED BY MX TEMPS YESTERDAY ACROSS THE PLAINS...WILL NOT MAKE THE SAME MISTAKE TODAY AND HAVE GONE ON THE HIGH SIDE OF GUIDANCE...GIVING US LOWER TO MID 90S ACROSS THE PLAINS. FORECAST HIGH OF 95 FOR KPUB THIS AFTERNOON WOULD BREAK THE OLD RECORD OF 94 FOR THIS DATE. FIRE WX STILL A CONCERN THRU THIS AFTERNOON. RED FLAG CONDITIONS LOOK A BIT SPOTTY ACROSS THE AREA TODAY...MAINLY DUE TO MARGINAL WIND GUSTS...BUT WITH DRY AND VERY WARM CONDITIONS WILL KEEP THE RED FLAG WARNING GOING AS ISSUED. WITH THE HOLIDAY WEEKEND...IT WILL BE PARTICULARLY IMPORTANT TO GUARD AGAINST FIRE STARTS THE NEXT COUPLE DAYS. THUNDERSTORMS ACROSS THE NM BORDER ARE SLOWLY DIMINISHING THIS MORNING AND SHOULD WRAP UP BY SUNRISE. THE DRYLINE RETREATS TO THE KS BORDER THIS AFTERNOON...SO ONLY A SLIGHT THREAT FOR TS ACTIVITY...MAINLY ALONG AND E OF HGWY 287 THROUGH BACA...PROWERS AND KIOWA COUNTIES. THERE COULD POTENTIALLY BE A STRONG STORM OR TWO RIGHT NR THE BORDER BY LATER THIS AFTERNOON. STORMS WILL GRADUALLY DIMINISH AFTER SUNSET. WILL BE A RATHER MILD NIGHT AS TEMPS ALOFT STAY RATHER HIGH...AND S-SW WINDS ARE SLOW TO DIMINISH THROUGH THE NIGHT...PARTICULARLY OVER THE FAR ERN COUNTIES. ROSE .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 440 AM MDT SAT MAY 25 2013 .SUNDAY AND MONDAY...DRY AND WARM SOUTHWEST FLOW ALOFT CONTINUES OVER THE REGION AHEAD OF THE TROUGH OVER THE PACIFIC NORTHWEST. DRY LINE MAY MOVE WEST OF THE KANSAS BORDER DURING THE NIGHT...BUT IT WILL MOVE EAST OF THE KANSAS BORDER DURING THE DAY. HAVE ISSUED A FIRE WEATHER WATCH FOR SUNDAY FOR ALL REGIONS OF THE CWA WITH CRITICAL FUELS. THERE WILL NOT BE MUCH OF A PROBLEM REACHING THE RELATIVE HUMIDITY CRITERIA AS MINIMUM HUMIDITIES ARE MOSTLY IN THE SINGLE DIGITS. WINDS ARE MORE OF A CONCERN...BUT THERE SHOULD BE FREQUENT GUSTS ABOVE 25 MPH ON SUNDAY. ON MONDAY...WINDS MAY BE LIGHTER...ESPECIALLY OVER THE NORTHERN SECTIONS. WOULD NOT BE SURPRISED LATER SHIFTS ISSUE FIRE WEATHER WATCHES FOR MONDAY FOR PARTS OF THE REGION. GRIDS ONLY HAVE SILENT POPS FOR BOTH DAYS GIVEN DRY AIRMASS OVER THE REGION. .TUESDAY...UPPER TROUGH WILL START APPROACHING COLORADO. MID LEVEL MOISTURE WILL MOVE INTO CENTRAL COLORADO...WITH A CHANCE FOR SOME AFTERNOON THUNDERSTORMS OVER THE CENTRAL MOUNTAINS. DRY SOUTHWEST FLOW MAY CONTINUE OVER THE EASTERN TWO THIRDS OF THE CWA. SOME FIRE WEATHER HIGHLIGHTS MAY EVENTUALLY BE NEEDED FOR PORTIONS OF THE CWA ON TUESDAY. .WEDNESDAY THROUGH FRIDAY...EC AND GFS CONTINUE TO DISAGREE ON THE SPEED AND TRAJECTORY OF THE STRONGER UPPER TROUGH. EC HAS CONSISTENTLY BEEN MORE AMPLIFIED AND SLOWER WITH THE TROUGH. THE EC SOLUTION COULD ALLOW FOR SOME LOW LEVEL MOISTURE TO ADVECT INTO EASTERN COLORADO RESULTING IN PRECIPITATION OVER MUCH OF THE REGION WEDNESDAY. THE GFS IS FASTER AND FURTHER NORTH...KEEPING WESTERLY WINDS OVER MUCH OF THE REGION. THE GFS SOLUTION WOULD ONLY PRODUCE LIGHT RAIN...IF ANY...FOR MUCH OF THE REGION. A FEW ENSEMBLE MEMBERS SUPPORT THE EC SOLUTION...BUT A MAJORITY FOLLOW THE OPERATIONAL GFS. GEM ALSO FOLLOWS GFS SOLUTION. WHILE MAJORITY OF GUIDANCE FOLLOWS GFS...AM NOT DISMISSING EC SOLUTION YET GIVEN EC PAST TRACK RECORD. .THURSDAY AND FRIDAY...MODELS AGREE WITH UPPER LOW DEVELOPING OVER THE NORTHERN ROCKIES...THEN MOVING EASTWARD INTO THE NORTHERN PLAINS. THIS PATTERN WOULD CONFINE PRECIPITATION MOSTLY TO NORTHERN AND CENTRAL COLORADO MOUNTAINS. TEMPERATURES WILL BE COOLER DUE TO COOLER AIR ALOFT...BUT WESTERLY FLOW WOULD LIMIT ANY PRECIPITATION TO LIGHT SHOWERS. --PGW-- && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1104 AM MDT SAT MAY 25 2013 VFR CONDITIONS EXPECTED AT TAF SITES WITH GUSTY SOUTH TO SOUTHWEST WINDS EXPECTED TO INCREASE FOR ALL THREE LOCATIONS DURING THE AFTERNOON. GUSTS TO 25KTS WILL BE POSSIBLE...WITH HIGHER GUSTS TO AROUND 30-35 KTS POSSIBLE OVER/NEAR THE MOUNTAINS THROUGH THE AFTERNOON. WINDS SHOULD DECREASE AROUND 02Z...WITH LIGHT DRAINAGE WINDS EXPECTED OVERNIGHT. ISOLATED -TSRA WILL BE POSSIBLE LATE THIS AFTERNOON THROUGH THIS EVENING ALONG THE CO/KS BORDER. && .PUB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ221-222-225- 227. FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR COZ221-222-225-227-233-237. && $$ UPDATE...KT SHORT TERM...ROSE LONG TERM...PGW AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1022 AM MDT SAT MAY 25 2013 .UPDATE... ISSUED AT 1009 AM MDT SAT MAY 25 2013 WINDS HAVE ALREADY BEEN QUITE GUSTY ACROSS SOUTHERN PORTIONS OF THE SOUTHEAST PLAINS AND SOME MOUNTAIN AREAS THIS MORNING...AND IS FORECAST TO SPREAD INTO MOST OF THE LOWER ELEVATIONS BY THIS AFTERNOON. WHERE FUELS ARE CRITICAL THIS WILL RESULT IN HIGH FIRE DANGER. MAIN CHANGE TO THE GRIDS WAS TO DROP SFC DEW POINTS ACROSS THE MTS/I-25 CORRIDOR AS YESTERDAY THEY DROPPED INTO THE SINGLE DIGITS AND LOWER TEENS AND SEE NO REASON WHY THEY WON`T DO THE SAME TODAY. HRRR SEEMS TO HAVE LATCHED ON TO THIS WELL AND HAVE USED THESE GRIDS TO BLEND TOWARDS. SHORT RANGE HIGH RES MODELS POINT TO BEST POTENTIAL FOR THUNDERSTORMS ALONG THE CO/KS BORDER DURING THE LATE AFTERNOON. HAVE TRIMMED BACK WESTERN EXTENT OF POPS TO BETTER REFLECT THIS. LOOKS LIKE PORTIONS OF EASTERN LAS ANIMAS AND WESTERN BACA COUNTY COULD SEE AN HOUR OR TWO OF CRITICAL TO NEAR CRITICAL FIRE WEATHER CONDITIONS THIS AFTERNOON. HOWEVER DRY LINE SHOULD WAVER BACK WESTWARD INTO BACA COUNTY EARLY THIS EVENING AS CONVECTION FIRES ALONG THE DRY LINE. WINDS ALSO APPEAR TO SLACKEN OFF SOME ACROSS EASTERN LAS ANIMAS COUNTY AS THE SFC TROF DEEPENS AND BEST GRADIENT SHIFTS SOUTH AND EASTWARD. THUS WILL HOLD OFF ON FIRE WEATHER HIGHLIGHTS FOR THESE AREAS. -KT && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 440 AM MDT SAT MAY 25 2013 ...HOT... JULY-LIKE WX EXPECTED TODAY AS DRY SW WINDS ALOFT CONTINUE TO OVERSPREAD THE AREA...AND PRECIP REMAINS MOSTLY OUTSIDE OUR CWA. H7 TEMPS RISE ANOTHER DEGREE OR SO...AND AFTER GETTING BURNED BY MX TEMPS YESTERDAY ACROSS THE PLAINS...WILL NOT MAKE THE SAME MISTAKE TODAY AND HAVE GONE ON THE HIGH SIDE OF GUIDANCE...GIVING US LOWER TO MID 90S ACROSS THE PLAINS. FORECAST HIGH OF 95 FOR KPUB THIS AFTERNOON WOULD BREAK THE OLD RECORD OF 94 FOR THIS DATE. FIRE WX STILL A CONCERN THRU THIS AFTERNOON. RED FLAG CONDITIONS LOOK A BIT SPOTTY ACROSS THE AREA TODAY...MAINLY DUE TO MARGINAL WIND GUSTS...BUT WITH DRY AND VERY WARM CONDITIONS WILL KEEP THE RED FLAG WARNING GOING AS ISSUED. WITH THE HOLIDAY WEEKEND...IT WILL BE PARTICULARLY IMPORTANT TO GUARD AGAINST FIRE STARTS THE NEXT COUPLE DAYS. THUNDERSTORMS ACROSS THE NM BORDER ARE SLOWLY DIMINISHING THIS MORNING AND SHOULD WRAP UP BY SUNRISE. THE DRYLINE RETREATS TO THE KS BORDER THIS AFTERNOON...SO ONLY A SLIGHT THREAT FOR TS ACTIVITY...MAINLY ALONG AND E OF HGWY 287 THROUGH BACA...PROWERS AND KIOWA COUNTIES. THERE COULD POTENTIALLY BE A STRONG STORM OR TWO RIGHT NR THE BORDER BY LATER THIS AFTERNOON. STORMS WILL GRADUALLY DIMINISH AFTER SUNSET. WILL BE A RATHER MILD NIGHT AS TEMPS ALOFT STAY RATHER HIGH...AND S-SW WINDS ARE SLOW TO DIMINISH THROUGH THE NIGHT...PARTICULARLY OVER THE FAR ERN COUNTIES. ROSE .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 440 AM MDT SAT MAY 25 2013 .SUNDAY AND MONDAY...DRY AND WARM SOUTHWEST FLOW ALOFT CONTINUES OVER THE REGION AHEAD OF THE TROUGH OVER THE PACIFIC NORTHWEST. DRY LINE MAY MOVE WEST OF THE KANSAS BORDER DURING THE NIGHT...BUT IT WILL MOVE EAST OF THE KANSAS BORDER DURING THE DAY. HAVE ISSUED A FIRE WEATHER WATCH FOR SUNDAY FOR ALL REGIONS OF THE CWA WITH CRITICAL FUELS. THERE WILL NOT BE MUCH OF A PROBLEM REACHING THE RELATIVE HUMIDITY CRITERIA AS MINIMUM HUMIDITIES ARE MOSTLY IN THE SINGLE DIGITS. WINDS ARE MORE OF A CONCERN...BUT THERE SHOULD BE FREQUENT GUSTS ABOVE 25 MPH ON SUNDAY. ON MONDAY...WINDS MAY BE LIGHTER...ESPECIALLY OVER THE NORTHERN SECTIONS. WOULD NOT BE SURPRISED LATER SHIFTS ISSUE FIRE WEATHER WATCHES FOR MONDAY FOR PARTS OF THE REGION. GRIDS ONLY HAVE SILENT POPS FOR BOTH DAYS GIVEN DRY AIRMASS OVER THE REGION. .TUESDAY...UPPER TROUGH WILL START APPROACHING COLORADO. MID LEVEL MOISTURE WILL MOVE INTO CENTRAL COLORADO...WITH A CHANCE FOR SOME AFTERNOON THUNDERSTORMS OVER THE CENTRAL MOUNTAINS. DRY SOUTHWEST FLOW MAY CONTINUE OVER THE EASTERN TWO THIRDS OF THE CWA. SOME FIRE WEATHER HIGHLIGHTS MAY EVENTUALLY BE NEEDED FOR PORTIONS OF THE CWA ON TUESDAY. .WEDNESDAY THROUGH FRIDAY...EC AND GFS CONTINUE TO DISAGREE ON THE SPEED AND TRAJECTORY OF THE STRONGER UPPER TROUGH. EC HAS CONSISTENTLY BEEN MORE AMPLIFIED AND SLOWER WITH THE TROUGH. THE EC SOLUTION COULD ALLOW FOR SOME LOW LEVEL MOISTURE TO ADVECT INTO EASTERN COLORADO RESULTING IN PRECIPITATION OVER MUCH OF THE REGION WEDNESDAY. THE GFS IS FASTER AND FURTHER NORTH...KEEPING WESTERLY WINDS OVER MUCH OF THE REGION. THE GFS SOLUTION WOULD ONLY PRODUCE LIGHT RAIN...IF ANY...FOR MUCH OF THE REGION. A FEW ENSEMBLE MEMBERS SUPPORT THE EC SOLUTION...BUT A MAJORITY FOLLOW THE OPERATIONAL GFS. GEM ALSO FOLLOWS GFS SOLUTION. WHILE MAJORITY OF GUIDANCE FOLLOWS GFS...AM NOT DISMISSING EC SOLUTION YET GIVEN EC PAST TRACK RECORD. .THURSDAY AND FRIDAY...MODELS AGREE WITH UPPER LOW DEVELOPING OVER THE NORTHERN ROCKIES...THEN MOVING EASTWARD INTO THE NORTHERN PLAINS. THIS PATTERN WOULD CONFINE PRECIPITATION MOSTLY TO NORTHERN AND CENTRAL COLORADO MOUNTAINS. TEMPERATURES WILL BE COOLER DUE TO COOLER AIR ALOFT...BUT WESTERLY FLOW WOULD LIMIT ANY PRECIPITATION TO LIGHT SHOWERS. --PGW-- && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 440 AM MDT SAT MAY 25 2013 VFR CONDITIONS EXPECTED FOR THE TAF SITES NEXT 24 H. STORMS WILL BE CONFINED TO NEAR THE KS BORDER LATE THIS AFTERNOON...BUT A COUPLE COULD BE ON THE STRONG SIDE WITH SOME HAIL. WINDS WILL ALSO BE A BIT GUSTY FROM THE S TO SW OVR THE ERN CO PLAINS. ROSE && .PUB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ221-222-225- 227. FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR COZ221-222-225-227-233-237. && $$ UPDATE...KT SHORT TERM...ROSE LONG TERM...PGW AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS MIAMI FL
236 PM EDT SAT MAY 25 2013 .SHORT TERM (TONIGHT-MONDAY NIGHT)... PLENTY OF DRY AIR ALONG WITH RISING UPPER HEIGHTS IN THE WAKE OF THE FRONTAL BOUNDARY THAT PASSED THROUGH TODAY WILL LEAD TO MORE OF A SUPPRESSED ENVIRONMENT THROUGH THE REMAINDER OF THE WEEKEND. MODEL TIME HEIGHTS/SOUNDINGS AROUND THE LOCAL AREA REFLECT THIS AND GENERALLY INDICATE MOST OF THE MOISTURE REMAINING CONFINED WITHIN THE LOWER 4 KFT UNDERNEATH A STRONG SUBSIDENCE INVERSION. PRECIPITABLE WATER VALUES ARE FORECAST TO STEADILY DROP TONIGHT AND BOTTOM OUT JUST ABOVE HALF OF AN INCH SUNDAY BEFORE STEADILY TRENDING BACK UP INTO THE UPCOMING WEEK. HOWEVER...MODERATE NORTHEASTERLY WINDS AND PLENTY OF LOW-LEVEL MOISTURE MAY ALLOW FOR A FEW SHALLOW BRIEF SHOWERS TO DEVELOP OVER THE ADJACENT ATLANTIC WATERS AND SPREAD ASHORE THROUGH THE REMAINDER OF THE WEEKEND...ESPECIALLY THROUGH THE OVERNIGHT AND EARLY MORNING HOURS. THIS LINES UP WELL WITH THE LATEST WRF SOLUTIONS...WHICH INDICATE A FEW LIGHT SHOWERS DEVELOPING AND SPREADING ASHORE OVER THE NORTHERN AREAS LATER TONIGHT INTO SUNDAY. ON MONDAY...DEEP EASTERLY FLOW UP TO AROUND 18 KFT ALONG WITH INCREASING MOISTURE MAY LEAD TO FEW SHOWERS DEVELOPING INLAND AND TOWARD THE GULF COAST AREAS THROUGH THE AFTERNOON/EVENING HOURS. HOWEVER...IN THE ABSENCE OF A GULF COAST SEA BREEZE DUE TO THE MODERATE EASTERLY FLOW IN PLACE ALONG WITH THE MID-LEVEL DRY AIR...MAINLY BRIEF SHOWERS WILL BE ANTICIPATED. ALONG THE EAST COAST...TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL EACH DAY. 85/AG .LONG TERM (TUESDAY-FRIDAY)... ADDITIONAL MOISTURE IS FORECAST TO ENTER THE REGION EARLY NEXT WEEK AS A MID TO UPPER LEVEL TROUGH IS FORECAST TO DEEPEN IN THE EASTERN GULF WITH A CHANCE OF SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. THERE IS SOME CONSENSUS AMONGST THE MODEL GUIDANCE THAT DEEPER LAYERED TROPICAL MOISTURE AND A DEEPENING OF THE MID TO UPPER LEVEL TROUGH COULD OCCUR AROUND MID-WEEK AND PERSIST FOR A COUPLE OF DAYS WITH MORE WIDESPREAD CONVECTION POSSIBLE. WILL HAVE TO WAIT AND SEE IF FUTURE GUIDANCE PERSISTS WITH THESE SYNOPTIC FEATURES. BD && .AVIATION... EASTERLY FLOW WILL PREVAIL THROUGH THE REMAINDER OF THE AFTERNOON ACROSS THE SOUTH FLORIDA AREA WITH VFR CONDITIONS. A FEW SHOWERS HAVE DEVELOPED THIS AFTERNOON ACROSS EXTREME SOUTHERN MAINLAND MONROE COUNTY. THE LATEST HRRR DEPICTS A FEW MORE SHOWERS DEVELOPING ACROSS THIS AREA AND IN COLLIER COUNTY OVER THE NEXT FEW HOURS...POSSIBLY AFFECTING KAPF. BELIEVE THE SHOWER COVERAGE WILL BE SPARSE AND DID NOT CARRY ANY MENTION FOR THE KAPF TAF. EASTERLY FLOW SHOULD CONTINUE OVERNIGHT AT AROUND 10 KNOTS AT ALL TAF SITES BEFORE BECOMING GUSTY AGAIN TOMORROW. && .MARINE... WINDS AND SEAS WILL QUICKLY INCREASE THROUGH THE REMAINDER OF THE WEEKEND IN THE WAKE OF A WEAK FRONTAL BOUNDARY AS HIGH PRESSURE BUILDS OVER THE REGION. ALTHOUGH ADVISORY LEVEL WINDS AND SEAS ARE NOT ANTICIPATED AT THIS TIME...MARINERS OPERATING SMALL CRAFT ARE ENCOURAGED TO EXERCISE CAUTION...MAINLY OVER THE ATLANTIC WATERS THIS WEEKEND. AT THE EAST COAST BEACHES...STRONG RIP CURRENTS WILL BE LIKELY BY SUNDAY DUE TO MODERATE ONSHORE WINDS AND BUILDING SURF. && .FIRE WEATHER... DESPITE THE DRIER AIR THAT IS FORECAST TO SPREAD OVER THE AREA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE UPCOMING WEEK...RELATIVE HUMIDITIES ARE FORECAST TO REMAIN ABOVE CRITICAL LEVELS EACH DAY. EASTERLY WINDS WILL BECOME GUSTY THROUGH THE AFTERNOON PERIODS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 72 82 73 83 / - 10 10 10 FORT LAUDERDALE 76 85 77 86 / - 10 20 10 MIAMI 75 84 75 85 / - 10 20 20 NAPLES 69 91 69 91 / - 10 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT-TERM DISCUSSION/MARINE/FIRE...85/AG LONG-TERM DISCUSSION...BD AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS LINCOLN IL
315 PM CDT SAT MAY 25 2013 .DISCUSSION... ISSUED 253 PM CDT SAT MAY 25 2013 HIGH PRESSURE RIDGE JUST TO THE EAST NOT QUITE STRONG ENOUGH TO DAMPEN LEFTOVER MCS ACTIVITY MOVING INTO CENTRAL ILLINOIS THIS AFTERNOON. WIDESPREAD SHOWERS AND ISOLATED THUNDER THROUGHOUT THE EARLY AFTERNOON HOURS SLOWLY LOSING ITS STRENGTH AND THUNDER. CLEARING SLOWLY MOVING TO THE EAST...THOUGH PLENTY OF -RA AND SPRINKLES LIKELY. 4KM WRF DOING A FAIR JOB...IF NOT A FEW HOURS BEHIND SCHEDULE. EXTRAPOLATING THE ERROR WOULD GIVE A BRIEF BREAK WITH MORE SCATTERED ACTIVITY BEFORE THE NEXT ROUND. TODAYS WEATHER EXPECTED TO CONTINUE THROUGH MONDAY BEFORE SLOWING ON TUESDAY. MODELS IN PRETTY DECENT AGREEMENT THROUGH MID WEEK BEFORE DIVERGING ON THE HANDLING OF THE UPPER WAVE PATTERN WITH THE TROF OVER THE ERN HALF OF THE CONUS...AND ITS MOVEMENT AND TILT AS IT PUSHES THE UPPER RIDGE OUT OF THE MIDWEST. TIMING ET AL IN COMPLETE DISAGREEMENT BEYOND FH120. SHORT TERM...TONIGHT THROUGH MONDAY... PERIODIC SHOWERS AND THUNDERSTORMS LIKELY THROUGH MONDAY. WARM AIR BUILDING UNDER THE RIDGE OVER THE PLAINS...AND A FRONT DELINEATING THE BOUNDARY BETWEEN THE WARMER AIR TO THE SW AND THE COOLER AIR OVER THE REGION ALMOST QUASI STATIONARY ALONG THE MISS RIVER VALLEY FOR THE REMAINDER OF THE HOLIDAY WEEKEND. A SERIES OF SHORT WAVES TOPPING THE RIDGE AND DIVING INTO ILX WILL KEEP THE POPS IN PLACE THROUGH THE HOLIDAY WEEKEND. TEMPS CONTINUE TO REMAIN MILD...EVEN THOUGH WARMING A COUPLE DEGREES EACH DAY...UNTIL THE WARM FRONT FINALLY PASSES THROUGH THE AREA MON NIGHT/TUESDAY. LONG TERM...TUESDAY THROUGH FRIDAY... WARM FRONT LIFTING THROUGH THE REGION MON NIGHT AS THE ERN EDGE OF THE RIDGE BREAKS DOWN AND PLENTY OF WARM AIR MOVES IN AT MIDLEVELS. PRECIP SLOWLY REDUCING IN COVERAGE AND MUCH WARMER INTO THE WORK WEEK. WESTERN TROF DIGS IN...AMPLIFYING THE WAVE PATTERN OVER THE CONUS AND LEAVING THE UPPER MIDWEST IN SWRLY FLOW...AND MUCH OF IL IN WEAK FLOW...IF ANY...UNDER THE BUILDING RIDGE. VERY WARM MIDLEVELS AND THE GUIDANCE STILL BEING PULLED DOWN A BIT BY CLIMATOLOGY INFLUENCE. HAVE BOOSTED TEMPS TO COMPENSATE...STILL MAY NOT BE ENOUGH. RETURNING POPS ON THURS NIGHT/FRI GETTING DELAYED A BIT MORE IN THIS RUN....AND STILL VERY MUCH IN DEBATE AS THE GFS AND ECMWF DIVERGE QUITE A BIT WITH THE PROGRESSION OF THE WAVE PATTERN AT DAY 7/8. HJS && .AVIATION... ISSUED 1243 PM CDT SAT MAY 25 2013 LARGE RAIN SHIELD HAS OVERSPREAD THE CENTRAL ILLINOIS TAF SITES AT MIDDAY. THUNDER HAS BEEN ON THE WANE...AND HAVE REMOVED THUNDER AT ALL SITES BY ABOUT 21-22Z. HAVE SEEN SOME MVFR VISIBILITIES AT TIMES IN THE HEAVIER SHOWERS...BUT CEILINGS WILL REMAIN FAIRLY HIGH. MAIN QUESTION LATER ON IS WITH REDEVELOPMENT OF NOCTURNAL CONVECTION TO THE NORTHWEST. MOST MODELS FAVOR IT DEVELOPING IN IOWA SIMILAR TO LAST NIGHT THEN MOVING SOUTHEAST...ALTHOUGH THE LATEST RAP MODEL IS INDICATING NORTHEAST MISSOURI AND WESTERN ILLINOIS FOR INITIATION. HAVE MADE LITTLE CHANGE TO EARLIER TAFS IN REGARDS TO THIS...ASIDE FROM MINOR TIMING ADJUSTMENTS...FAVORING RAIN AND VCTS MENTIONS WHILE THE POTENTIAL CONTINUES TO BE EVALUATED OVER THE NEXT FEW HOURS. HAVE TRIED TO INDICATE A FEW HOURS OF DRIER CONDITIONS LATE IN THE PERIOD...BUT CONFIDENCE IS LOW AT THIS TIME DUE TO THE EARLIER QUESTION OF OVERNIGHT CONVECTION. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1243 PM CDT SAT MAY 25 2013 .DISCUSSION... ISSUED 1011 AM CDT SAT MAY 25 2013 OVERNIGHT MCS FROM IOWA HAS BEEN SHOWING SOME WARMING CLOUD TOPS AS IT DROPS SOUTHEAST INTO WESTERN ILLINOIS. HAVE BEEN SEEING SOME LIGHT ECHOES ON RADAR AS FAR EAST AS THE INDIANA BORDER...BUT THE AIR MASS OVER CENTRAL ILLINOIS IS VERY DRY AS EVIDENCED BY THE MORNING SOUNDING AND LAPS ANALYSIS...SO A LOT OF THIS HAS BEEN ALOFT. FINALLY SEEING SOME MEASURABLE RAIN AROUND GALESBURG THOUGH. RAP AND HRRR MODELS DOING A REASONABLE JOB WITH THE MCS ITSELF...AND SHOW THE RAIN MOST WIDESPREAD THROUGH EARLY AFTERNOON BEFORE BREAKING UP. MOST OF THE THUNDERSTORMS HAVE BEEN DROPPING SOUTHEASTWARD TOWARD WEST CENTRAL ILLINOIS...SO HAVE CUT BACK SOME ON THE THUNDER CHANCES...ESPECIALLY NORTH OF I-74. HAVE SENT OUT SOME UPDATES TO SIGNIFICANTLY INCREASE THE RAIN CHANCES ACROSS THE NORTHWEST HALF OF THE CWA...WITH LESSER CHANGES NEEDED ACROSS THE SOUTHEAST. GEELHART && .AVIATION... ISSUED 1243 PM CDT SAT MAY 25 2013 LARGE RAIN SHIELD HAS OVERSPREAD THE CENTRAL ILLINOIS TAF SITES AT MIDDAY. THUNDER HAS BEEN ON THE WANE...AND HAVE REMOVED THUNDER AT ALL SITES BY ABOUT 21-22Z. HAVE SEEN SOME MVFR VISIBILITIES AT TIMES IN THE HEAVIER SHOWERS...BUT CEILINGS WILL REMAIN FAIRLY HIGH. MAIN QUESTION LATER ON IS WITH REDEVELOPMENT OF NOCTURNAL CONVECTION TO THE NORTHWEST. MOST MODELS FAVOR IT DEVELOPING IN IOWA SIMILAR TO LAST NIGHT THEN MOVING SOUTHEAST...ALTHOUGH THE LATEST RAP MODEL IS INDICATING NORTHEAST MISSOURI AND WESTERN ILLINOIS FOR INITIATION. HAVE MADE LITTLE CHANGE TO EARLIER TAFS IN REGARDS TO THIS...ASIDE FROM MINOR TIMING ADJUSTMENTS...FAVORING RAIN AND VCTS MENTIONS WHILE THE POTENTIAL CONTINUES TO BE EVALUATED OVER THE NEXT FEW HOURS. HAVE TRIED TO INDICATE A FEW HOURS OF DRIER CONDITIONS LATE IN THE PERIOD...BUT CONFIDENCE IS LOW AT THIS TIME DUE TO THE EARLIER QUESTION OF OVERNIGHT CONVECTION. GEELHART && .PREV DISCUSSION... ISSUED 242 AM CDT SAT MAY 25 2013 UNSETTLED WEATHER THROUGH THE MEMORIAL DAY WEEKEND...FOLLOWED BY MUCH WARMER/DRIER CONDITIONS FOR THE MIDDLE AND END OF NEXT WEEK. SHORT TERM...TODAY THROUGH MONDAY CONVECTION CURRENTLY DEVELOPING ALONG THE NOSE OF A 45-50KT LLJ OVER NEBRASKA IS EXPECTED TO TRACK E/SE INTO THE AREA TODAY. MAIN QUESTION WILL BE HOW FAR EAST THE PRECIP CAN PENETRATE INTO SPRAWLING SURFACE RIDGE AXIS EXTENDING FROM THE GREAT LAKES TO THE GULF COAST. 00Z KILX UPPER AIR SOUNDING SHOWED A VERY DRY PROFILE FROM THE SURFACE UP TO ABOUT 500MB. ANY PRECIP MOVING INTO THIS HOSTILE ENVIRONMENT WILL INITIALLY EVAPORATE UNTIL THE AIRMASS IS SUFFICIENTLY MOISTENED. DUE TO THE CONTINUED DRY E/NE LOW-LEVEL FLOW...HAVE REMOVED POPS ACROSS EAST-CENTRAL AND SOUTHEAST ILLINOIS FOR THE MORNING HOURS. FURTHER WEST...HIGH-RES HRRR SUGGESTS NEBRASKA CONVECTION WILL EVENTUALLY SPREAD INTO WEST-CENTRAL ILLINOIS TOWARD MIDDAY. WILL THEREFORE CARRY CHANCE POPS DURING THE MORNING...THEN LIKELY THIS AFTERNOON FOR LOCATIONS ALONG/WEST OF I-55. INITIAL AREA OF CONVECTION WILL DISSIPATE AS IT MOVES INTO EAST-CENTRAL ILLINOIS LATER THIS AFTERNOON AND EVENING. MEANWHILE...LOW-LEVEL JET WILL ONCE AGAIN STRENGTHEN AND FOCUS A RENEWED ROUND OF SHOWERS/THUNDER UPSTREAM ACROSS IOWA TONIGHT. THIS ACTIVITY IS THEN EXPECTED TO TRACK E/SE INTO CENTRAL ILLINOIS LATE TONIGHT INTO SUNDAY. WITH AIRMASS MOISTENED FROM INITIAL PRECIP TODAY...THINK RAIN CHANCES WILL BE HIGHER ACROSS THE BOARD TONIGHT/SUNDAY. WILL THEREFORE CARRY LIKELY POPS EVERYWHERE EXCEPT THE FAR SE CWA. ADDITIONAL SHOWERS/STORMS WILL FIRE ON MONDAY...AS PERSISTENT FRONTAL BOUNDARY FINALLY BEGINS TO SHIFT SLOWLY NORTHWARD ACROSS THE AREA. WILL CONTINUE TO HIT POPS HARD...ESPECIALLY ACROSS THE CENTRAL AND NORTHERN ZONES. TOTAL RAINFALL FROM THIS MULTI-DAY EVENT WILL BE LIGHTEST ALONG THE ILLINOIS/INDIANA BORDER WHERE AMOUNTS OF ONE HALF TO ONE INCH WILL BE COMMON. HIGHER RAIN TOTALS WILL BE FOCUSED FURTHER WEST...ESPECIALLY WEST OF I-55 WHERE ONE AND A HALF TO TWO INCHES WILL BE LIKELY. LONG TERM...TUESDAY THROUGH FRIDAY AS UPPER TROUGH DIGS OVER THE WESTERN CONUS...DOWNSTREAM RIDGE WILL BUILD ACROSS THE MIDWEST/OHIO RIVER VALLEY. THIS WILL FINALLY GIVE THE SURFACE FRONT A GOOD PUSH NORTHWARD BY TUESDAY...RESULTING IN LOWER POPS AND HIGHER TEMPS. WILL ONLY CARRY LOW CHANCE POPS ACROSS THE FAR NORTHERN CWA...WHILE HIGH TEMPS CLIMB INTO THE LOWER TO MIDDLE 80S. AFTER THAT...MODEL SOLUTIONS VARY SOMEWHAT CONCERNING HOW QUICKLY THE UPPER RIDGE EVENTUALLY BREAKS DOWN. GIVEN AMPLIFIED PATTERN...THINK THIS WILL BE LATER RATHER THAN SOONER...SO HAVE GONE WITH A VERY WARM AND DRY FORECAST THROUGH THURSDAY. WEAKENING FRONTAL BOUNDARY MAY PUSH INTO THE REGION BY THE END OF THE WEEK...SO HAVE INCLUDED CHANCE FOR SHOWERS/THUNDER ON FRIDAY WITH CONTINUED WARM TEMPS WELL INTO THE 80S. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
125 PM EDT SAT MAY 25 2013 .AVIATION... //DISCUSSION... DRY AND STABLE CONDITIONS WILL EXIST THROUGH THE TAF PERIOD AS HIGH PRESSURE REMAINS CONTROL. RIDGE POSITIONING WILL FAVOR A LIGHT NORTHERLY WIND COMPONENT. FEW DIURNAL CU WILL QUICKLY DISSIPATE WITH THE LOSS OF HEATING. SE MICHIGAN WILL REMAIN ALONG THE EASTERN FRINGE OF A THICKER MID LEVEL CLOUD DECK WITH A BRIEF PERIOD OF BKN CIRRUS POSSIBLE THROUGH THE LATTER HALF OF THE DAY. //DTW THRESHOLD THREATS... * NONE. && .PREV DISCUSSION...ISSUED 325 AM EDT SAT MAY 25 2013 SHORT TERM...TODAY AND TONIGHT EARLY MORNING MSAS ANALYSIS IS SHOWING A SURFACE RIDGE EXTENDING SOUTHWARD THROUGH THE LAKE SUPERIOR/MICHIGAN/HURON BASINS. THE BEST SURFACE RIDGING COMPONENT INSIDE OF THE CWA IS ACROSS THE NORTHERN THUMB DOWN INTO PORT HURON. PERUSING THROUGH THE SURFACE OBSERVATIONS...FEELING IS THE BEST POTENTIAL FOR ANY FROST FORMATION WILL BE IN THE THUMB AND LOW LYING AREAS OF THE GLACIAL TERRAIN WITH THE LOCAL OFFICE TEMPERATURE AT 33 DEGREES AS OF 230 AM LDT. WILL MAINTAIN THE FROST ADVISORY AS IS FOR SIMPLICITY. THERE HAS BEEN A DECENT RADAR PRESENTATION OVERNIGHT ACROSS PORTIONS OF MN/WI/IA TIED TO THE AGEOSTROPHIC RESPONSE OF MERGING AND SHEARING OF SHORTWAVE ENERGY. ONE HR PRECIPITATION AMOUNTS HAVE BEEN LESSENING AS THE PRECIPITATION/VIRGA PUSHES FARTHER TO THE SOUTHEAST. THIS IS LIKELY IN RESPONSE TO INCREASING CONFLUENCE ALOFT AS THE ENTRANCE REGION LIES DIRECTLY OVER LOWER MICHIGAN. THE BEST UPPER LEVEL FORCING IN THE FORM OF 700-500MB FRONTOGENESIS WILL BRUSH FAR SOUTHWESTERN SECTIONS OF THE STATE BETWEEN 12-15Z...BEFORE PASSING HARMLESSLY TO THE SOUTH. THE AMOUNT OF AMBIENT DRY AIR IN THE LOWEST 12 KFT AGL SUPPORTS VIRTUALLY NO PRECIPITATION POTENTIAL TODAY. THE PREFERENCE REGARDING HIGH CLOUD PROG LIES WITH THE 25.05Z RUC WHICH BRINGS HIGH CLOUDS INTO THE SOUTHWESTERN 2/3RDS OF THE CWA BETWEEN 9-16Z THIS MORNING. INCREASED INSOLATION WITH SOME MODERATION OF THE AIRMASS WILL SUPPORT A SOLID 3-8F DEGREE UPTICK IN HIGH TEMPERATURES. EXPECT READINGS TO RANGE FROM THE MIDDLE 50S IN THE FAR NORTHERN THUMB/LAKE HURON SHORELINE TO THE MIDDLE 60S DETROIT SOUTHWARD. SURFACE HIGH PRESSURE WILL EXPAND ACROSS THE CENTRAL GREAT LAKES TONIGHT...BRINGING THE PROSPECTS OF ANOTHER COOL TO COLD NIGHT. DIFFERENTIAL AIRMASS RECOVERY SHOULD BE GOOD FOR A FEW DEGREES OFF THIS MORNINGS MINS. WORKED WITH A BLEND OF UNDERCUT GUIDANCE WITH SOME PERSISTENCE. EXPECTED LOWS TONIGHT SHOULD RANGE FROM THE LOWER TO MIDDLE 30S IN THE THUMB TO LOWER 40S SOUTHEAST OF THE TERRAIN. LONG TERM...SUNDAY THROUGH FRIDAY LOWER MICHIGAN WILL RESIDE BETWEEN A HIGH AMPLITUDE RIDGE ACROSS THE UPPER MIDWEST AND A DEEP UPPER LOW LIFTING FROM NEW ENGLAND INTO THE CANADIAN MARITIMES DURING THE LATER HALF OF THE WEEKEND...SUSTAINING A CONFLUENT FLOW ALOFT. AT THE SFC...THIS WILL TRANSLATE TO HIGH PRESSURE BUILDING FROM THE UPPER GREAT LAKES ON SUNDAY TO THE EASTERN GREAT LAKES ON MONDAY. OTHER THAN THE POTENTIAL FOR SOME HIGH CLOUDS...SKIES SHOULD REMAIN MAINLY CLEAR WITH VERY DRY AIR OVERHEAD. TEMPS WILL SLOWLY MODERATE...LEADING TO AN OVERALL WARMING TREND HEADING INTO MEMORIAL DAY. EXPECT MIXING DEPTHS MAY OVERACHIEVE WITH PLENTY OF SUNSHINE AND SUBSTANTIAL LOW LEVEL DRY AIR. THIS SUPPORTS LEANING TOWARD THE HIGHER END OF GUIDANCE MAX TEMPS /MID TO UPPER 60S SUNDAY AND AROUND 70 MONDAY/. THE DRY AIRMASS AND WEAK SFC GRADIENT WILL SUPPORT OPTIMAL RADIATIONAL COOLING POTENTIAL...SO MINS SUN NIGHT WILL CONTINUE TO BE QUITE COLD FOR LATE MAY /UPPER 30S TO MID 40S/. THE MID LEVEL RIDGE IS FORECAST TO BREAK DOWN EARLY NEXT WEAK AS NUMEROUS SHORT WAVE IMPULSES ARE EJECTED OUT OF THE LONG WAVE TROUGH OVER THE WRN US AND ACROSS THE CNTRL/NRN PLAINS. THE BULK OF THE 00Z MODEL SUITE SUGGEST MCS DEVELOPMENT ACROSS THE UPPER MIDWEST OR WRN GREAT LAKES MON AFTERNOON/NIGHT AS LOW LEVEL INFLOW STRENGTHENS. THE POTENTIAL FOR REMNANT MCS ACTIVITY TO ADVANCE INTO SE MI REMAINS HIGHLY UNCERTAIN AT THIS TIME. WHILE SEVERAL MODEL SOLUTIONS ARE QUITE BULLISH WITH QPF OVER SE MI MON NIGHT AND TUES...THERE IS LIKELY SOME SEMBLANCE OF CONVECTIVE FEEDBACK IN THE MODELS. THERE IS ALSO CONCERN THAT THE MODELS HAVE A POOR HANDLING OF MCS PROPAGATION...WHICH COULD LEAD TO REMNANT CONVECTION BEING MUCH FARTHER SOUTH. THUS PLAN TO CARRY VERY LOW CHANCE POPS TUESDAY. PERSISTENT LOW LEVEL S-SWLY FLOW SHOULD HOWEVER LIFT A WARMER AND MORE HUMID AIRMASS INTO SRN LOWER MI BY MID WEEK...MARKED BY THE PASSAGE OF A SFC WARM FRONT. THIS WILL JUSTIFY A CHANCE OF SHOWERS/THUNDERSTORMS LATE TUES THROUGH WED. THE ECMWF REMAINS STEADFAST IN DEVELOPING A MORE AMPLIFIED UPPER TROUGH OVER THE WRN US BY MIDWEEK AS ENERGY EJECTS OUT OF THE GULF OF ALASKA AND INTO THE WEST COAST. A SEASONALLY STRONG UPPER JET WITHIN THE BASE OF THE DEEP GULF OF ALASKA UPPER LOW AND CURRENT AMPLIFIED NATURE OF THE FLOW LENDS SUPPORT TO THE ECMWF. THIS SOLUTION BUILDS THE SUBTROPICAL RIDGE FARTHER NORTH INTO THE ERN US LATE IN THE WEEK AND SUGGESTS SE MI MAY BE CAPPED. EVEN THE LESS AMPLIFIED GFS BUILDS MID LEVEL HEIGHTS SUBSTANTIALLY ACROSS SE MI. THUS THE FORECAST FOR THE LATER HALF OF NEXT WEEK WILL HAVE VERY LOW POPS WITH MAX TEMPS WELL INTO THE 80S. MARINE... A STABLE ANTICYCLONE WILL EXPAND ACROSS THE GREAT LAKES THROUGH THE HOLIDAY WEEKEND. THIS WEATHER FEATURE WILL BE RESPONSIBLE FOR MORE TYPICAL MARINE CONDITIONS FOR LATE MAY. WAVE HEIGHTS ARE ONLY EXPECTED TO RANGE IN THE 1 TO 2 FOOT RANGE IN MANY AREAS THROUGHOUT THE WEEKEND. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MR SHORT TERM...CB LONG TERM....SC MARINE.......CB YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
603 PM CDT Sat May 25 2013 .SHORT TERM...(This Evening through Sunday) Issued at 345 PM CDT SAT MAY 25 2013 Very few changes were needed to the forecast through tomorrow. Based on latest high res models, radar, and satellite trends it appears, other than a stray shower across the MO/IA border, the CWA should remain dry this evening. Later tonight a small cluster of storms is progged to work in from the west, but the latest HRRR depicts a weaker system than what much of the NRN third of the CWA experienced early this morning. At this time I have an overnight precip forecast that favors the northern half of the CWA with higher chance pops compared to lower chances to the south. As for tomorrow, more of the same with lingering scattered morning showers and weak thunderstorms with perhaps redevelopment in the afternoon. Temperature wise the CWA will remain mild and rather muggy as compared to the past several days under partly to mostly cloudy skies. .LONG TERM...(Sunday Night through Saturday) Issued at 345 PM CDT SAT MAY 25 2013 The potential for wet weather looks to bracket either end of the work week, though there will be plenty of dry days in between. Shortwave ridge will be dominating the Central Plains as Memorial Day dawns, with nocturnal thunderstorm activity likely lingering through the morning hours. In general, operational and ensemble models continue to advertise that this modest ridge will stay in place across the Plains States through Tuesday, when the west CONUS trough will finally begin to shift east. As the trough begins to move into the Plains the storm track will shift farther north which should give most locations in our forecast areas a break from the rain chances. However, given the negative tilt to the trough as it shifts into the Plains, and the general synoptic pattern, thoughts are that storms will not only return tot he forecast, but severe weather may plague the region by the end of the work week. Currently, the best potential for storms looks to be Thursday night and Friday night as the nocturnal jet cranks up ahead of the west CONUS trough. Otherwise, with the prevailing storm track, and by extension the prevailing westerlies, remaining to the north of Kansas and Missouri through the work week we expect temperatures to rise to a category or two above normal through the week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday Evening) Issued at 603 PM CDT SAT MAY 25 2013 Convection has blossomed across western Kansas however models seem to be evaporating this convection as it moves eastward tonight. With temperature/dewpoint spreads of 15-20 degrees across the area, that seems reasonable so have left TAFs dry overnight. It appears better chance for convection may come tomorrow afternoon but no confidence in timing or placement to include in the TAF at the moment. GFS MOS/LAMP as well as NAM BUFR soundings are hinting at MVFR cigs tomorrow morning but continue to think boundary layer is too moist so have held off on inclusion in the TAF. Winds will be out of the south between 10-15kts through tomorrow afternoon when they will become gusty around 20-25kts. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ SHORT TERM...Pietrycha LONG TERM...Cutter AVIATION...73
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
347 PM CDT Sat May 25 2013 .SHORT TERM...(This Evening through Sunday) Issued at 345 PM CDT SAT MAY 25 2013 Very few changes were needed to the forecast through tomorrow. Based on latest high res models, radar, and satellite trends it appears, other than a stray shower across the MO/IA border, the CWA should remain dry this evening. Later tonight a small cluster of storms is progged to work in from the west, but the latest HRRR depicts a weaker system than what much of the NRN third of the CWA experienced early this morning. At this time I have an overnight precip forecast that favors the northern half of the CWA with higher chance pops compared to lower chances to the south. As for tomorrow, more of the same with lingering scattered morning showers and weak thunderstorms with perhaps redevelopment in the afternoon. Temperature wise the CWA will remain mild and rather muggy as compared to the past several days under partly to mostly cloudy skies. .LONG TERM...(Sunday Night through Saturday) Issued at 345 PM CDT SAT MAY 25 2013 The potential for wet weather looks to bracket either end of the work week, though there will be plenty of dry days in between. Shortwave ridge will be dominating the Central Plains as Memorial Day dawns, with nocturnal thunderstorm activity likely lingering through the morning hours. In general, operational and ensemble models continue to advertise that this modest ridge will stay in place across the Plains States through Tuesday, when the west CONUS trough will finally begin to shift east. As the trough begins to move into the Plains the storm track will shift farther north which should give most locations in our forecast areas a break from the rain chances. However, given the negative tilt to the trough as it shifts into the Plains, and the general synoptic pattern, thoughts are that storms will not only return tot he forecast, but severe weather may plague the region by the end of the work week. Currently, the best potential for storms looks to be Thursday night and Friday night as the nocturnal jet cranks up ahead of the west CONUS trough. Otherwise, with the prevailing storm track, and by extension the prevailing westerlies, remaining to the north of Kansas and Missouri through the work week we expect temperatures to rise to a category or two above normal through the week. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1232 PM CDT SAT MAY 25 2013 For this afternoon, I am expecting VFR cigs and vis along with south to southwest winds under 10 kts with brief gusts to 15 kts. Later tonight the possibility exists for the development of scattered SHRA and TSRA. Forecast confidence is low as to whether the three terminals will see any of the activity. For that reason have placed VCTS in the TAFS beginning late tonight. The scattered SHRA/TSRA are expected to persist through the remainder of the TAF period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ SHORT TERM...Pietrycha LONG TERM...Cutter AVIATION...Pietrycha
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
311 PM CDT SAT MAY 25 2013 .DISCUSSION... ALTHOUGH TIMING OF HIGHEST CONCENTRATION OF ANY CONVECTION IS THE MAIN CHALLENGE FOR ANY GIVEN PERIOD WELL INTO NEXT WEEK...PATTERN LOOKS TO REMAIN ACTIVE WITH PRECIP CHANCES GOOD IF NOT LIKELY MOST AREAS MOST EVENINGS/OVERNIGHT PDS. AT 19Z SURFACE BOUNDARY EXTENDED FROM JUST N OF FNB TO JUST SW OF OLU/BVN WITH RESIDUAL COOL OUTFLOW FROM MORNING CONVECTION REINFORCING FRONT. CONVERGENCE NEAR BOUNDARY HAD INCREASED CU FIELD WCNTRL ZONES AND LATEST RAP MESO ANALYSIS PLACED AXIS OF 2000-3000 J/KG ML CAPE ACROSS THAT AREA WITH LITTLE/NO CIN. SO THERE REMAINS SOME POSSIBILITY OF CONVECTION DEVELOPING NEAR/N OF THIS BOUNDARY EARLY THIS EVENING...ESPECIALLY AS ANY SUBSIDENCE EFFECTS OF DEPARTING MCV FROM EARLIER CONVECTION GETS FARTHER REMOVED. LATER THIS EVENING/OVERNIGHT HIGH PLAINS CONVECTION WILL PROBABLY MAKE A RUN TOWARD/INTO FA...POSSIBLY CONSOLIDATING MORE ACROSS NRN ZONES AIDED BY RR ENTRANCE REGION OF WEAK UPPER JET SEGMENT. HOWEVER...CAN/T RULE OUT ACTIVITY FARTHER S AS WELL SINCE BOUNDARY MAY NOT MOVE MUCH TONIGHT. LOW LEVEL JET DOES STRENGTHEN SOME INTO FRONT OVERNIGHT...BUT STRONGEST/MORE CONVERGENT AREA NOT NECESSARILY FOCUSED ACROSS THE FORECAST AREA...SO CONFIDENCE ON WIDESPREAD HEAVY RAINFALL NOT VERY GOOD. THAT SAID...SMALL AREA OF NRN IA ZONES DID PICK UP 1-2+ INCHES OF RAIN LAST NIGHT AND THAT AREA APPEARS TO HAVE THE HIGHEST CHANCE OF SIGNIFICANT RAINS TONIGHT AS MOISTURE REMAINS PLENTIFUL WITH PWATS AROUND 1.5 INCHES. THUS ISSUED A SMALL FLASH FLOOD WATCH NE OF OMAHA TO MATCH UP WITH DMX WHERE HEAVIER RAIN WAS MORE WIDESPREAD. DECREASED POPS DIURNALLY ON SUNDAY LIKE TODAY ALTHOUGH IT WAS NOTED THAT FOR SEVERAL RUNS NOW NAM HAD DEVELOPED A SMALL MCS AND DROPPED IT SE ACROSS FA DURING THE AFTERNOON. FORECAST WAS NOT BASED ON THAT SCENARIO. ALSO MODELS HINTING AT MORE LOW LEVEL MOISTURE WITH LOW CLOUDS POSSIBLY LINGERING INTO THE AFTERNOON. THUS INCREASED SKY COVER. IF CLOUDS HOLD ALL DAY CONVECTIVE DEVELOPMENT COULD BE ALTERED AS WELL AS HIGH TEMPERATURES. OTHERWISE...LIKELY POPS MANY AREAS AGAIN WERE MENTIONED SUN NIGHT. MONDAY POSSIBLY A VERY SIMILAR SCENARIO...ALTHOUGH FINER DETAILS PROBABLY IMPACTED BY PREVIOUS PERIODS CONVECTION BOTH DAYS. SOME INDICATION BY MODELS THAT A FRONT...POSSIBLY AIDED BY OVERNIGHT CONVECTION...WILL PUSH S INTO NRN ZONES ON TUESDAY AS A STRONGER WAVE EJECTS ACROSS CANADIAN PRAIRIE. COOLING AT H85 MINIMAL FOR THAT AREA...BUT NE WINDS AND POSSIBLE LOW CLOUDS COULD KEEP MAX TEMPS COOLER AND THIS COULD NEED ATTENTION IN LATER FORECASTS. OTHERWISE...THIS BOUNDARY AND UPPER TROUGH BEGINNING TO APPROACH AREA WILL KEEP AREA ACTIVE TUESDAY/TUE NGT. WEDNESDAY COULD POSSIBLY BE MORE OF A LULL WITH WARMER TEMPERATURES BEFORE STRONGER ENERGY PUNCHES ACROSS CNTRL PLAINS WED NGT/THURSDAY INCREASING COVERAGE/CHCS AGAIN. ALTHOUGH SEVERE POTENTIAL WILL EXIST INTO TUESDAY...THIS STRONGER TROUGH COULD BRING A HEIGHTENED RISK OF SVR WEATHER TO AREA LATE NEXT WEEK. CHERMOK && .AVIATION... 18Z TAFS FOR KOMA...KLNK AND KOFK. A WARM FRONT SLOWLY LIFTING OVER THE CNTRL PLAINS WILL BE THE FOCUS FOR TSRA ACTIVITY OVER ERN NEB LATER TONIGHT. LLVL MOISTURE WILL CONTINUE STREAMING NWD INTO THE REGION THROUGH THIS EVENING. THIS ALONG WITH A STRENGTHENING LLVL JET...TSRA ACTIVITY SHOULD INCREASE SOMEWHAT IN AREAL COVERAGE...MAINLY OVER NERN NEB. DUE TO SOME UNCERTAINTY THOUGH HOW FAST THE SFC BNDRY WILL LIFT...HAVE DECIDED TO JUST COVER ALL SITES WITH PROB30 GROUPS BTWN 26/03Z- 12Z. MEANWHILE...WITH PERSISTENT MOISTURE ADVECTION EXPECTED...CONDITIONS SHOULD BEGIN DETERIORATING FROM VFR TO IFR BY OR SHORTLY AFT 26/06Z. GOOD INDICATION FROM MODEL GUIDANCE THAT MVFR CONDITIONS THEN WILL PREVAIL THE REST OF THE FCST PD. DEE && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...FLASH FLOOD WATCH FROM MIDNIGHT CDT TONIGHT THROUGH SUNDAY MORNING FOR IAZ043-055-056. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1245 PM CDT SAT MAY 25 2013 .UPDATE... ISSUED AT 1131 AM CDT SAT MAY 25 2013 THIS WILL SERVE AS THE NOON ESTF UPDATE. TEMPS OVER OUR KS COUNTIES ARE RAPIDLY APPROACHING 80F. SO HIGH TEMPS HAVE BEEN RAISED ALL AREAS FOR THIS AFTN. THE FLOOD WARNING FOR SHERMAN/HOWARD COUNTIES WAS ALLOWED TO EXPIRE AT 1030AM. CALLS TO REGIONAL DISPATCH INDICATE WATERS WERE RECEDING. HOWEVER...COORDINATED WITH THE RFC AND WE WILL BE CLOSELY MONITORING AREA RIVERS PARTICULARLY N OF I-80 AFTER THE VERY HVY RAINS LAST NGT. HIGHEST TOTAL SO FAR IS 4.28" 2 W OF LOUP CITY. THANK YOU VERY MUCH TO ALL COOP/SPOTTER/NE-RAIN/COCORAHS OBSERVERS. THE BOUNDARY LEFT BY LAST NGT`S MCS WILL PLAY AN IMPORTANT ROLE IN TSTM DEVELOPMENT THIS AFTN-EVE. MEAN S LOW-LVL FLOW WILL BE MAINTAINED JUST E OF THE LEE TROF WHICH WILL RESULT IN CONVERGENCE AND ASCENT ALONG THIS BOUNDARY. WE/VE NOTED A PLUME OF VERY WARM MID-LVL TEMPS ON THE DDC SOUNDING WHICH WILL ADVECT OVER THE FCST AREA TODAY. THIS WILL DELAY TSTM DEVELOP UNTIL LATE...AND COULD KEEP IT FROM OCCURRING AT ALL S OF THE BOUNDARY. RADAR AND VIS SATELLITE SHOWS AN MCV JUST SW OF THE FCST AREA NEAR HYS. THIS WILL BE A WILDCARD AS IT COULD TRIGGER TSTMS IN THE WARM SECTOR...BUT DOES IT OCCUR DURING THE DAYLGT HRS? IT/S HEADING NE AND WILL MOVE ACROSS OUR SE COUNTIES. IF IT HOLDS OFF UNTIL TNGT THEN IT COULD BE E OF THE FCST AREA. WITH VERY LITTLE CLOUD COVER N OF THE BOUNDARY...DIABATIC HEATING WILL DESTABILIZE THE ATMS. TEMPS IN THE 80S...DWPTS IN THE 60S AND MID-LVL LAPSE RATES OF 8 DEG C/KM WILL RESULT IN MLCAPE OF 2000-3000 J/KG. MID-LVL SHEAR WILL BE AROUND 30 KTS...SUPPORTIVE OF SUPERCELLS DUE TO BACKED LOW-LVL SE WINDS. 0-1 KM EHI WILL BE IN EXCESS OF 1 WHERE WINDS ARE BACKED. THIS COMBINED WITH LOWEST LCL HGTS SUGGESTS TORNADO POTENTIAL WILL BE ALONG AND N OF A LINE FROM LXN-HJH. SATELLITE-DERIVED PW SHOWS A PLUME OF SUBTROPICAL MSTR EXTENDING N FROM THE CARIBBEAN INTO THE CNTRL PLAINS. LBF/OAX/TOP 12Z SOUNDINGS ARE ALL 150-170% OF NORMAL. ANY CLUSTERING OF TSTMS WILL THREATEN FLASH FLOODING...ESPECIALLY HERE HVY RAIN OCCURRED LAST NGT. ORDINARY STORM MVMT WILL BE 05025 KTS. SUPERCELL MVMT: E 10-15 KTS WHICH COULD ALSO BE TROUBLE FOR EXCESSIVE RAINFALL. HWO AND EHWO HAVE BEEN UPDATED WITH OUR LATEST THINKING. UPDATE ISSUED AT 920 AM CDT SAT MAY 25 2013 MCS HAS BASICALLY EXITED. RADAR IS SHOWING SOME SHWRS STILL PERCOLATING FROM HLC-PHG AND DRIFTING NE TOWARD THE STATE LINE. THESE SHWRS /WITH AN OCCASIONAL RUMBLE OF THUNDER/ WERE DEVELOPING AS THE REMAINS OF THE LLJ ARE STILL LARGELY PERPENDICULAR TO THE CONVECTIVELY-REINFORCED WARM FRONT THAT EXTENDS W-E ACROSS NRN KS. EXPECT THESE SHWRS TO EVENTUALLY END. SO SHORT-TERM ADJUSTMENTS THRU NOON HAVE ADJUSTED POPS AND SKYCOVER ACCORDINGLY. 12Z LBF/OAX/TOP SOUNDINGS SUPPORT HIGH TEMPS IN THE LOW-MID 80S E OF HWY 281 AND MID-UPR 80S TO THE W. WE WILL CONT TO EVALUATE TSTM AND SVR WX POTENTIAL FOR THIS AFTN- EVE. CERTAINLY THE BOUNDARY LAID DOWN FROM THIS MCS WILL BE WATCHED CLOSELY. PLEASE FOLLOW OUR LSR/RTP/LCO PRODUCTS FOR THE IMPRESSIVE RAINFALL TOTALS OVERNGT. MANY REPORTS OF 2-3" IN A SWATH FROM SHERMAN-HALL- HAMILTON-CLAY-THAYER COUNTIES. THIS MAY SET THE STAGE FOR SOME FLOODING WITH MULTIPLE THREATS OF TSTMS THE NEXT SVRL DAYS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 423 AM CDT SAT MAY 25 2013 FOCUS REMAINS ON TSTM POTENTIAL. TSTMS CONTINUE EARLY THIS MORNING WITH MCS ROLLING EAST ACROSS CENTRAL/EASTERN NEBRASKA. MAIN IMPACT CURRENTLY FM CONVECTION IS HEAVY RAINFALL...WITH MANY LOCATIONS NORTH OF INTERSTATE 80 PICKING UP AT LEAST AN INCH OF RAIN. WE HAVE HAD ONE REPORT OF 3.13 INCHES SO FAR AT LOUP CITY WITH RAIN STILL FALLING. THIS INITIAL ROUND OF CONVECTION WILL CONTINUE TO MOVE EAST/END THIS MORNING THEN ATTENTION TURNS TO ADDITIONAL CHANCES FOR CONVECTION THIS AFTN. SFC BOUNDARY HAS SETTLED NEAR THE NEB/KS STATELINE AND FRONT IS PROGGED TO LIFT NORTHWARD THIS AFTN INTO SC NEB...WITH SFC LOW ORIENTED IN EASTERN COLORADO AND DRY LINE ALONG THE HIGH PLAINS REGION. FRONTAL BOUNDARY AND ANY RESIDUAL OUTFLOW BOUNDARIES WILL BE FOCUS FOR CONVECTION AGAIN THIS AFTN/EVE AND BOUNDARY PLACEMENT WILL NEED TO BE MONITORED CLOSELY. CAP LOOKS TO HOLD INITIALLY HOWEVER MODELS ARE INDICATING DEVELOPMENT ALONG THE DRY LINE AND ALONG/NORTH OF WARM FRONTAL BOUNDARY...AND HAVE FOLLOWED CLOSER TO RAP MODEL FOR POTENTIAL DEVELOPMENT THIS AFTN. STORMS FOR TODAY/TONIGHT HAVE THE POTENTIAL TO BE MORE VOLATILE WITH SEVERE PARAMETERS INDICATING POTENTIAL FOR SUPERCELLS. INSTABILITY IS PROGGED AROUND 4000 J/KG WITH SHEAR OF 40KTS OR SO AND STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS AND EVEN TORNADOES IN VCNTY OF BOUNDARIES. HEAVY RAINFALL/FLOODING ALSO REMAINS A CONCERN DUE TO THE HEAVY OVERNIGHT/EARLY THIS MORNING AND PRECIPITABLE WATER VALUES ARE ON THE ORDER OF AN INCH TO INCH AND A HALF AND ARE A 100 TO 150 PERCENT OF NORMAL. ALL OF THIS BEING SAID...MODELS ARE NOT CONSISTENT IN FRONTAL POSITION WHICH IS KEY TO DEVELOPMENT THIS AFTN. AGAIN FEEL RAP AND LATEST SREF RUN HAS A BETTER HANDLE ON THE FARTHER SOUTH WARM FRONTAL POSITION ACROSS OUR AREA TODAY...AND WILL NEED TO MONITOR CLOSELY. OTHERWISE...LOOK FOR SOME WARMER TEMPS THIS AFTN AND STEADY/GUSTY WINDS WITH THE HIGHEST WIND SPEEDS EXPECTED ACROSS NC KANSAS/SOUTH OF WARM FRONT...WHERE WINDY CONDITIONS ARE POSSIBLE WITH GUSTS OF 30+ MPH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 423 AM CDT SAT MAY 25 2013 SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MOST EVERY DAY AND TEMPERATURES THROUGH THE PERIOD. A VERY ACTIVE WEATHER PATTERN WILL AFFECT THE FORECAST AREA THROUGH THE PERIOD. AN UPPER LEVEL LOW DEVELOPS IN THE WESTERN CONUS AND GRADUALLY MOVES THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY FRIDAY. THIS UPPER LOW WILL SEND WAVES INTO THE FORECAST AREA THROUGH THE PERIOD. THE MODELS ARE SIMILAR IN THE MAIN FEATURES...BUT THE ECMWF HAS A LITTLE STRONGER AMPLITUDE MID WEEK. EACH OF THE WAVES WILL HAVE A CHANCE FOR SOME THUNDERSTORMS WHEN THEY MOVE THROUGH. IT CERTAINLY WILL NOT BE A RAIN OUT...IT WILL NOT RAIN ALL OF THE TIME...BUT THERE WILL BE CHANCES FOR SOME SHOWERS AND THUNDERSTORMS AT VARIOUS TIMES DURING THE PERIOD. THE BEST CHANCES FOR THUNDERSTORMS WILL BE SUNDAY AFTERNOON AND SUNDAY NIGHT...DURING WHICH TIME THE CAPE APPROACHES 5000 J/KG. ANOTHER GOOD CHANCE WILL BE MONDAY AFTERNOON AND MONDAY NIGHT WITH CAPES OVER 5000 J/KG AGAIN. BEYOND MONDAY THE MODELS HAVE A FEW TIMING DIFFERENCES WITH THE UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND THEREFORE TIMING THUNDERSTORMS IS MORE OF A CHALLENGE. TEMPERATURES WILL BE THE WARMEST SUNDAY THROUGH TUESDAY THEN SLOWLY COOL OFF TOWARD THE END OF THE WEEK. TEMPERATURES SHOULD STILL REMAIN ABOVE NORMAL FOR THIS TIME OF YEAR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1244 PM CDT SAT MAY 25 2013 UNCERTAINTY IS ABOVE AVERAGE DUE TO TSTM POTENTIAL. THIS AFTN: VFR WITH A SLGT CHC OF AN IFR TSTM AFTER 21Z. SSE WINDS WILL GUST TO AROUND 22 KTS. TNGT: VFR MUCH OF THE NGT BUT THERE IS A SLGT CHC OF A TSTM. JUST CANNOT PINPOINT IT ATTM. GUSTINESS OF SSE WINDS WILL DIMINISH AROUND SUNSET...BUT THERE COULD BE SOME OCCASIONAL GUSTS TO NEAR 20 KTS. SUN THRU 18Z: VFR. SSE WINDS GUST UP TO 25 KTS. CIG CONFIDENCE: MEDIUM VSBY CONFIDENCE: MEDIUM WIND CONFIDENCE: HIGH EXCEPT NEAR TSTMS WX CONFIDENCE: LOW DUE TO TSTM POTENTIAL && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...FAY LONG TERM...JCB AVIATION...HALBLAUB
AREA FORECAST DISCUSSION...CORRECTED
NWS HASTINGS NE
1138 AM CDT SAT MAY 25 2013 .UPDATE... ISSUED AT 1131 AM CDT SAT MAY 25 2013 THIS WILL SERVE AS THE NOON ESTF UPDATE. TEMPS OVER OUR KS COUNTIES ARE RAPIDLY APPROACHING 80F. SO HIGH TEMPS HAVE BEEN RAISED ALL AREAS FOR THIS AFTN. THE FLOOD WARNING FOR SHERMAN/HOWARD COUNTIES WAS ALLOWED TO EXPIRE AT 1030AM. CALLS TO REGIONAL DISPATCH INDICATE WATERS WERE RECEDING. HOWEVER...COORDINATED WITH THE RFC AND WE WILL BE CLOSELY MONITORING AREA RIVERS PARTICULARLY N OF I-80 AFTER THE VERY HVY RAINS LAST NGT. HIGHEST TOTAL SO FAR IS 4.28" 2 W OF LOUP CITY. THANK YOU VERY MUCH TO ALL COOP/SPOTTER/NE-RAIN/COCORAHS OBSERVERS. THE BOUNDARY LEFT BY LAST NGT`S MCS WILL PLAY AN IMPORTANT ROLE IN TSTM DEVELOPMENT THIS AFTN-EVE. MEAN S LOW-LVL FLOW WILL BE MAINTAINED JUST E OF THE LEE TROF WHICH WILL RESULT IN CONVERGENCE AND ASCENT ALONG THIS BOUNDARY. WE/VE NOTED A PLUME OF VERY WARM MID-LVL TEMPS ON THE DDC SOUNDING WHICH WILL ADVECT OVER THE FCST AREA TODAY. THIS WILL DELAY TSTM DEVELOP UNTIL LATE...AND COULD KEEP IT FROM OCCURRING AT ALL S OF THE BOUNDARY. RADAR AND VIS SATELLITE SHOWS AN MCV JUST SW OF THE FCST AREA NEAR HYS. THIS WILL BE A WILDCARD AS IT COULD TRIGGER TSTMS IN THE WARM SECTOR...BUT DOES IT OCCUR DURING THE DAYLGT HRS? IT/S HEADING NE AND WILL MOVE ACROSS OUR SE COUNTIES. IF IT HOLDS OFF UNTIL TNGT THEN IT COULD BE E OF THE FCST AREA. WITH VERY LITTLE CLOUD COVER N OF THE BOUNDARY...DIABATIC HEATING WILL DESTABILIZE THE ATMS. TEMPS IN THE 80S...DWPTS IN THE 60S AND MID-LVL LAPSE RATES OF 8 DEG C/KM WILL RESULT IN MLCAPE OF 2000-3000 J/KG. MID-LVL SHEAR WILL BE AROUND 30 KTS...SUPPORTIVE OF SUPERCELLS DUE TO BACKED LOW-LVL SE WINDS. 0-1 KM EHI WILL BE IN EXCESS OF 1 WHERE WINDS ARE BACKED. THIS COMBINED WITH LOWEST LCL HGTS SUGGESTS TORNADO POTENTIAL WILL BE ALONG AND N OF A LINE FROM LXN-HJH. SATELLITE-DERIVED PW SHOWS A PLUME OF SUBTROPICAL MSTR EXTENDING N FROM THE CARIBBEAN INTO THE CNTRL PLAINS. LBF/OAX/TOP 12Z SOUNDINGS ARE ALL 150-170% OF NORMAL. ANY CLUSTERING OF TSTMS WILL THREATEN FLASH FLOODING...ESPECIALLY HERE HVY RAIN OCCURRED LAST NGT. ORDINARY STORM MVMT WILL BE 05025 KTS. SUPERCELL MVMT: E 10-15 KTS WHICH COULD ALSO BE TROUBLE FOR EXCESSIVE RAINFALL. HWO AND EHWO HAVE BEEN UPDATED WITH OUR LATEST THINKING. UPDATE ISSUED AT 920 AM CDT SAT MAY 25 2013 MCS HAS BASICALLY EXITED. RADAR IS SHOWING SOME SHWRS STILL PERCOLATING FROM HLC-PHG AND DRIFTING NE TOWARD THE STATE LINE. THESE SHWRS /WITH AN OCCASIONAL RUMBLE OF THUNDER/ WERE DEVELOPING AS THE REMAINS OF THE LLJ ARE STILL LARGELY PERPENDICULAR TO THE CONVECTIVELY-REINFORCED WARM FRONT THAT EXTENDS W-E ACROSS NRN KS. EXPECT THESE SHWRS TO EVENTUALLY END. SO SHORT-TERM ADJUSTMENTS THRU NOON HAVE ADJUSTED POPS AND SKYCOVER ACCORDINGLY. 12Z LBF/OAX/TOP SOUNDINGS SUPPORT HIGH TEMPS IN THE LOW-MID 80S E OF HWY 281 AND MID-UPR 80S TO THE W. WE WILL CONT TO EVALUATE TSTM AND SVR WX POTENTIAL FOR THIS AFTN- EVE. CERTAINLY THE BOUNDARY LAID DOWN FROM THIS MCS WILL BE WATCHED CLOSELY. PLEASE FOLLOW OUR LSR/RTP/LCO PRODUCTS FOR THE IMPRESSIVE RAINFALL TOTALS OVERNGT. MANY REPORTS OF 2-3" IN A SWATH FROM SHERMAN-HALL- HAMILTON-CLAY-THAYER COUNTIES. THIS MAY SET THE STAGE FOR SOME FLOODING WITH MULTIPLE THREATS OF TSTMS THE NEXT SVRL DAYS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 423 AM CDT SAT MAY 25 2013 FOCUS REMAINS ON TSTM POTENTIAL. TSTMS CONTINUE EARLY THIS MORNING WITH MCS ROLLING EAST ACROSS CENTRAL/EASTERN NEBRASKA. MAIN IMPACT CURRENTLY FM CONVECTION IS HEAVY RAINFALL...WITH MANY LOCATIONS NORTH OF INTERSTATE 80 PICKING UP AT LEAST AN INCH OF RAIN. WE HAVE HAD ONE REPORT OF 3.13 INCHES SO FAR AT LOUP CITY WITH RAIN STILL FALLING. THIS INITIAL ROUND OF CONVECTION WILL CONTINUE TO MOVE EAST/END THIS MORNING THEN ATTENTION TURNS TO ADDITIONAL CHANCES FOR CONVECTION THIS AFTN. SFC BOUNDARY HAS SETTLED NEAR THE NEB/KS STATELINE AND FRONT IS PROGGED TO LIFT NORTHWARD THIS AFTN INTO SC NEB...WITH SFC LOW ORIENTED IN EASTERN COLORADO AND DRY LINE ALONG THE HIGH PLAINS REGION. FRONTAL BOUNDARY AND ANY RESIDUAL OUTFLOW BOUNDARIES WILL BE FOCUS FOR CONVECTION AGAIN THIS AFTN/EVE AND BOUNDARY PLACEMENT WILL NEED TO BE MONITORED CLOSELY. CAP LOOKS TO HOLD INITIALLY HOWEVER MODELS ARE INDICATING DEVELOPMENT ALONG THE DRY LINE AND ALONG/NORTH OF WARM FRONTAL BOUNDARY...AND HAVE FOLLOWED CLOSER TO RAP MODEL FOR POTENTIAL DEVELOPMENT THIS AFTN. STORMS FOR TODAY/TONIGHT HAVE THE POTENTIAL TO BE MORE VOLATILE WITH SEVERE PARAMETERS INDICATING POTENTIAL FOR SUPERCELLS. INSTABILITY IS PROGGED AROUND 4000 J/KG WITH SHEAR OF 40KTS OR SO AND STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS AND EVEN TORNADOES IN VCNTY OF BOUNDARIES. HEAVY RAINFALL/FLOODING ALSO REMAINS A CONCERN DUE TO THE HEAVY OVERNIGHT/EARLY THIS MORNING AND PRECIPITABLE WATER VALUES ARE ON THE ORDER OF AN INCH TO INCH AND A HALF AND ARE A 100 TO 150 PERCENT OF NORMAL. ALL OF THIS BEING SAID...MODELS ARE NOT CONSISTENT IN FRONTAL POSITION WHICH IS KEY TO DEVELOPMENT THIS AFTN. AGAIN FEEL RAP AND LATEST SREF RUN HAS A BETTER HANDLE ON THE FARTHER SOUTH WARM FRONTAL POSITION ACROSS OUR AREA TODAY...AND WILL NEED TO MONITOR CLOSELY. OTHERWISE...LOOK FOR SOME WARMER TEMPS THIS AFTN AND STEADY/GUSTY WINDS WITH THE HIGHEST WIND SPEEDS EXPECTED ACROSS NC KANSAS/SOUTH OF WARM FRONT...WHERE WINDY CONDITIONS ARE POSSIBLE WITH GUSTS OF 30+ MPH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 423 AM CDT SAT MAY 25 2013 SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MOST EVERY DAY AND TEMPERATURES THROUGH THE PERIOD. A VERY ACTIVE WEATHER PATTERN WILL AFFECT THE FORECAST AREA THROUGH THE PERIOD. AN UPPER LEVEL LOW DEVELOPS IN THE WESTERN CONUS AND GRADUALLY MOVES THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY FRIDAY. THIS UPPER LOW WILL SEND WAVES INTO THE FORECAST AREA THROUGH THE PERIOD. THE MODELS ARE SIMILAR IN THE MAIN FEATURES...BUT THE ECMWF HAS A LITTLE STRONGER AMPLITUDE MID WEEK. EACH OF THE WAVES WILL HAVE A CHANCE FOR SOME THUNDERSTORMS WHEN THEY MOVE THROUGH. IT CERTAINLY WILL NOT BE A RAIN OUT...IT WILL NOT RAIN ALL OF THE TIME...BUT THERE WILL BE CHANCES FOR SOME SHOWERS AND THUNDERSTORMS AT VARIOUS TIMES DURING THE PERIOD. THE BEST CHANCES FOR THUNDERSTORMS WILL BE SUNDAY AFTERNOON AND SUNDAY NIGHT...DURING WHICH TIME THE CAPE APPROACHES 5000 J/KG. ANOTHER GOOD CHANCE WILL BE MONDAY AFTERNOON AND MONDAY NIGHT WITH CAPES OVER 5000 J/KG AGAIN. BEYOND MONDAY THE MODELS HAVE A FEW TIMING DIFFERENCES WITH THE UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND THEREFORE TIMING THUNDERSTORMS IS MORE OF A CHALLENGE. TEMPERATURES WILL BE THE WARMEST SUNDAY THROUGH TUESDAY THEN SLOWLY COOL OFF TOWARD THE END OF THE WEEK. TEMPERATURES SHOULD STILL REMAIN ABOVE NORMAL FOR THIS TIME OF YEAR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 540 AM CDT SAT MAY 25 2013 TSTMS CONTINUE IN THE VICINITY OF KGRI EARLY THIS MORNING. THIS INITIAL ROUND OF CONVECTION WILL END THIS MORNING WITH REDEVELOPMENT OF STORMS FORECAST THIS AFTN AND EVENING. LOOK FOR VARIABLE WINDS TO TRANSITIION SOUTHERLY TODAY...BUT WILL BE VARIABLE/GUSTY IN VCNTY OF STORMS. CIGS/VSBYS WILL MAINLY BE VFR BUT WILL DROP TO MVFR AND POTENTIALLY NEAR IFR DURING TSTM ACTIVITY. SEVERE STORMS ARE POSSIBLE LATER TODAY/TONIGHT WITH LARGE HAIL/DAMAGING WINDS/HEAVY RAINFALL THE MAIN HAZARDS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...FAY LONG TERM...JCB AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1132 AM CDT SAT MAY 25 2013 .UPDATE... ISSUED AT 1131 AM CDT SAT MAY 25 2013 THIS WILL SERVE AS THE NOON ESTF UPDATE. TEMPS OVER OUR KS COUNTIES ARE RAPIDLY APPROACHING 80F. SO HIGH TEMPS HAVE BEEN RAISED ALL AREAS FOR THIS AFTN. THE FLOOD WARNING FOR SHERMAN/HOWARD COUNTIES WAS ALLOWED TO EXPIRE AT 1030AM. CALLS TO REGIONAL DISPATCH INDICATE WATERS WERE RECEDING. HOWEVER...COORDINATED WITH THE RFC AND WE WILL BE CLOSELY MONITORING AREA RIVERS PARTICULARLY N OF I-80 AFTER THE VERY HVY RAINS LAST NGT. HIGHEST TOTAL SO FAR IS 4.28" 2 W OF LOUP CITY. THANK YOU VERY MUCH TO ALL COOP/SPOTTER/NE-RAIN/COCORAHS OBSERVERS. WE BOUNDARY LEFT BY LAST NGT`S MCS WILL PLAY AN IMPORTANT ROLE IN TSTM DEVELOPMENT THIS AFTN-EVE. MEAN S LOW-LVL FLOW WILL BE MAINTAINED JUST E OF THE LEE TROF WHICH WILL RESULT IN CONVERGENCE AND ASCENT ALONG THIS BOUNDARY. WE/VE NOTED A PLUME OF VERY WARM MID-LVL TEMPS ON THE DDC SOUNDING WHICH WILL ADVECT OVER THE FCST AREA TODAY. THIS WILL DELAY TSTM DEVELOP UNTIL LATE...AND COULD KEEP IT FROM OCCURRING AT ALL S OF THE BOUNDARY. RADAR AND VIS SATELLITE SHOWS AN MCV JUST SW OF THE FCST AREA NEAR HYS. THIS WILL BE A WILDCARD AS IT COULD TRIGGER TSTMS IN THE WARM SECTOR...BUT DOES IT OCCUR DURING THE DAYLGT HRS? IT/S HEADING NE AND WILL MOVE ACROSS OUR SE COUNTIES. IF IT HOLDS OFF UNTIL TNGT THEN IT COULD BE E OF THE FCST AREA. WITH VERY LITTLE CLOUD COVER N OF THE BOUNDARY...DIABATIC HEATING WILL DESTABILIZE THE ATMS. TEMPS IN THE 80S...DWPTS IN THE 60S AND MID-LVL LAPSE RATES OF 8 DEG C/KM WILL RESULT IN MLCAPE OF 2000-3000 J/KG. MID-LVL SHEAR WILL BE AROUND 30 KTS...SUPPORTIVE OF SUPERCELLS DUE TO BACKED LOW-LVL SE WINDS. 0-1 KM EHI WILL BE IN EXCESS OF 1 WHERE WINDS ARE BACKED. THIS COMBINED WITH LOWEST LCL HGTS SUGGESTS TORNADO POTENTIAL WILL BE ALONG AND N OF A LINE FROM LXN-HJH. SATELLITE-DERIVED PW SHOWS A PLUME OF SUBTROPICAL MSTR EXTENDING N FROM THE CARIBBEAN INTO THE CNTRL PLAINS. LBF/OAX/TOP 12Z SOUNDINGS ARE ALL 150-170% OF NORMAL. ANY CLUSTERING OF TSTMS WILL THREATEN FLASH FLOODING...ESPECIALLY HERE HVY RAIN OCCURRED LAST NGT. ORDINARY STORM MVMT WILL BE 05025 KTS. SUPERCELL MVMT: E 10-15 KTS WHICH COULD ALSO BE TROUBLE FOR EXCESSIVE RAINFALL. HWO AND EHWO HAVE BEEN UPDATED WITH OUR LATEST THINKING. UPDATE ISSUED AT 920 AM CDT SAT MAY 25 2013 MCS HAS BASICALLY EXITED. RADAR IS SHOWING SOME SHWRS STILL PERCOLATING FROM HLC-PHG AND DRIFTING NE TOWARD THE STATE LINE. THESE SHWRS /WITH AN OCCASIONAL RUMBLE OF THUNDER/ WERE DEVELOPING AS THE REMAINS OF THE LLJ ARE STILL LARGELY PERPENDICULAR TO THE CONVECTIVELY-REINFORCED WARM FRONT THAT EXTENDS W-E ACROSS NRN KS. EXPECT THESE SHWRS TO EVENTUALLY END. SO SHORT-TERM ADJUSTMENTS THRU NOON HAVE ADJUSTED POPS AND SKYCOVER ACCORDINGLY. 12Z LBF/OAX/TOP SOUNDINGS SUPPORT HIGH TEMPS IN THE LOW-MID 80S E OF HWY 281 AND MID-UPR 80S TO THE W. WE WILL CONT TO EVALUATE TSTM AND SVR WX POTENTIAL FOR THIS AFTN- EVE. CERTAINLY THE BOUNDARY LAID DOWN FROM THIS MCS WILL BE WATCHED CLOSELY. PLEASE FOLLOW OUR LSR/RTP/LCO PRODUCTS FOR THE IMPRESSIVE RAINFALL TOTALS OVERNGT. MANY REPORTS OF 2-3" IN A SWATH FROM SHERMAN-HALL- HAMILTON-CLAY-THAYER COUNTIES. THIS MAY SET THE STAGE FOR SOME FLOODING WITH MULTIPLE THREATS OF TSTMS THE NEXT SVRL DAYS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 423 AM CDT SAT MAY 25 2013 FOCUS REMAINS ON TSTM POTENTIAL. TSTMS CONTINUE EARLY THIS MORNING WITH MCS ROLLING EAST ACROSS CENTRAL/EASTERN NEBRASKA. MAIN IMPACT CURRENTLY FM CONVECTION IS HEAVY RAINFALL...WITH MANY LOCATIONS NORTH OF INTERSTATE 80 PICKING UP AT LEAST AN INCH OF RAIN. WE HAVE HAD ONE REPORT OF 3.13 INCHES SO FAR AT LOUP CITY WITH RAIN STILL FALLING. THIS INITIAL ROUND OF CONVECTION WILL CONTINUE TO MOVE EAST/END THIS MORNING THEN ATTENTION TURNS TO ADDITIONAL CHANCES FOR CONVECTION THIS AFTN. SFC BOUNDARY HAS SETTLED NEAR THE NEB/KS STATELINE AND FRONT IS PROGGED TO LIFT NORTHWARD THIS AFTN INTO SC NEB...WITH SFC LOW ORIENTED IN EASTERN COLORADO AND DRY LINE ALONG THE HIGH PLAINS REGION. FRONTAL BOUNDARY AND ANY RESIDUAL OUTFLOW BOUNDARIES WILL BE FOCUS FOR CONVECTION AGAIN THIS AFTN/EVE AND BOUNDARY PLACEMENT WILL NEED TO BE MONITORED CLOSELY. CAP LOOKS TO HOLD INITIALLY HOWEVER MODELS ARE INDICATING DEVELOPMENT ALONG THE DRY LINE AND ALONG/NORTH OF WARM FRONTAL BOUNDARY...AND HAVE FOLLOWED CLOSER TO RAP MODEL FOR POTENTIAL DEVELOPMENT THIS AFTN. STORMS FOR TODAY/TONIGHT HAVE THE POTENTIAL TO BE MORE VOLATILE WITH SEVERE PARAMETERS INDICATING POTENTIAL FOR SUPERCELLS. INSTABILITY IS PROGGED AROUND 4000 J/KG WITH SHEAR OF 40KTS OR SO AND STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS AND EVEN TORNADOES IN VCNTY OF BOUNDARIES. HEAVY RAINFALL/FLOODING ALSO REMAINS A CONCERN DUE TO THE HEAVY OVERNIGHT/EARLY THIS MORNING AND PRECIPITABLE WATER VALUES ARE ON THE ORDER OF AN INCH TO INCH AND A HALF AND ARE A 100 TO 150 PERCENT OF NORMAL. ALL OF THIS BEING SAID...MODELS ARE NOT CONSISTENT IN FRONTAL POSITION WHICH IS KEY TO DEVELOPMENT THIS AFTN. AGAIN FEEL RAP AND LATEST SREF RUN HAS A BETTER HANDLE ON THE FARTHER SOUTH WARM FRONTAL POSITION ACROSS OUR AREA TODAY...AND WILL NEED TO MONITOR CLOSELY. OTHERWISE...LOOK FOR SOME WARMER TEMPS THIS AFTN AND STEADY/GUSTY WINDS WITH THE HIGHEST WIND SPEEDS EXPECTED ACROSS NC KANSAS/SOUTH OF WARM FRONT...WHERE WINDY CONDITIONS ARE POSSIBLE WITH GUSTS OF 30+ MPH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 423 AM CDT SAT MAY 25 2013 SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MOST EVERY DAY AND TEMPERATURES THROUGH THE PERIOD. A VERY ACTIVE WEATHER PATTERN WILL AFFECT THE FORECAST AREA THROUGH THE PERIOD. AN UPPER LEVEL LOW DEVELOPS IN THE WESTERN CONUS AND GRADUALLY MOVES THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY FRIDAY. THIS UPPER LOW WILL SEND WAVES INTO THE FORECAST AREA THROUGH THE PERIOD. THE MODELS ARE SIMILAR IN THE MAIN FEATURES...BUT THE ECMWF HAS A LITTLE STRONGER AMPLITUDE MID WEEK. EACH OF THE WAVES WILL HAVE A CHANCE FOR SOME THUNDERSTORMS WHEN THEY MOVE THROUGH. IT CERTAINLY WILL NOT BE A RAIN OUT...IT WILL NOT RAIN ALL OF THE TIME...BUT THERE WILL BE CHANCES FOR SOME SHOWERS AND THUNDERSTORMS AT VARIOUS TIMES DURING THE PERIOD. THE BEST CHANCES FOR THUNDERSTORMS WILL BE SUNDAY AFTERNOON AND SUNDAY NIGHT...DURING WHICH TIME THE CAPE APPROACHES 5000 J/KG. ANOTHER GOOD CHANCE WILL BE MONDAY AFTERNOON AND MONDAY NIGHT WITH CAPES OVER 5000 J/KG AGAIN. BEYOND MONDAY THE MODELS HAVE A FEW TIMING DIFFERENCES WITH THE UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND THEREFORE TIMING THUNDERSTORMS IS MORE OF A CHALLENGE. TEMPERATURES WILL BE THE WARMEST SUNDAY THROUGH TUESDAY THEN SLOWLY COOL OFF TOWARD THE END OF THE WEEK. TEMPERATURES SHOULD STILL REMAIN ABOVE NORMAL FOR THIS TIME OF YEAR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 540 AM CDT SAT MAY 25 2013 TSTMS CONTINUE IN THE VICINITY OF KGRI EARLY THIS MORNING. THIS INITIAL ROUND OF CONVECTION WILL END THIS MORNING WITH REDEVELOPMENT OF STORMS FORECAST THIS AFTN AND EVENING. LOOK FOR VARIABLE WINDS TO TRANSITIION SOUTHERLY TODAY...BUT WILL BE VARIABLE/GUSTY IN VCNTY OF STORMS. CIGS/VSBYS WILL MAINLY BE VFR BUT WILL DROP TO MVFR AND POTENTIALLY NEAR IFR DURING TSTM ACTIVITY. SEVERE STORMS ARE POSSIBLE LATER TODAY/TONIGHT WITH LARGE HAIL/DAMAGING WINDS/HEAVY RAINFALL THE MAIN HAZARDS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...FAY LONG TERM...JCB AVIATION...FAY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1239 PM CDT SAT MAY 25 2013 .UPDATE... ISSUED AT 1239 PM CDT SAT MAY 25 2013 BASED ON LATEST MESOANALYSIS...ADDED A SLIGHT CHANCE THIS AFTERNOON FOR WESTERN CWA IN SOUTH CENTRAL SOUTH DAKOTA. LATEST SURFACE PLOT SHOWS THE NORTHWARD MOVING WARM FRONT NOW LOCATED FROM NORTH OF RAPID CITY...TO NORTH OF ALLIANCE/O`NEILL NEBRASKA...AND SOUTHEAST THROUGH SE NEBRASKA. CU ALSO DEVELOPING BETWEEN KIEN/KVTN WITH SURFACE HEATING. LATEST SPC MESOANALYSIS SHOWS AXIS OF LITTLE CIN AND SBCAPE OF 1500+ J/KG STRETCHED ACROSS SOUTH CENTRAL SOUTH DAKOTA. WITH DAYTIME HEATING AND WEAK VORT MAX IN FLOW ALOFT APPROACHING...ISOLATED CELL INITIATION IS POSSIBLE THIS AFTERNOON...ALTHOUGH MUCH OF THE INITIATION IS EXPECTED OUT IN WESTERN SODAK WITH STRONGER SHORT WAVE AND HIGHER INSTABILITY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM CDT SAT MAY 25 2013 THUNDERSTORM COMPLEX OVER NEBRASKA OVERNIGHT CONTINUES EARLY THIS MORNING. SEEING SHOWERS AND STORMS BEGINNING TO EXPAND ACROSS NORTHWEST IOWA AS WELL AS LOW LEVEL THETAE ADVECTION INCREASES. HIGH RES MODEL SUITE LOOK TO HAVE A PRETTY GOOD HANDLE ON THIS ACTIVITY. EXPECT IT TO CONTINUE THIS MORNING AND POSSIBLY EXPAND A BIT FURTHER NORTH INTO PORTIONS OF SOUTHWEST MINNESOTA. LOWERED POPS ACROSS SOUTHEAST SOUTH DAKOTA...AS ALL INDICATIONS ARE THAT THESE STORMS WILL NOT DEVELOP NORTHWEST OF THEIR CURRENT LOCATION. MOST OF THE STORMS SHOULD BE EAST OF THE CWA BY 16Z. MAIN IMPACTS WILL BE BRIEFLY HEAVY RAIN AND POSSIBLY SMALL HAIL WITH THESE CELLS...AS EFFECTIVE SHEAR AND CAPE ARE TOO LOW FOR ANY SEVERE THREAT. MUCH OF THE AFTERNOON SHOULD THEN BE DRY ACROSS THE CWA WITH AN AREA OF SUBSIDENCE LIKELY BEHIND THIS MORNINGS SHORTWAVE. WARM FRONTAL BOUNDARY WILL POSITION ITSELF SOUTH OF THE MISSOURI RIVER THIS AFTERNOON. HRRR AND RAP TRY TO BREAK THE CAP THEIR THIS AFTERNOON...BUT BOTH THESE MODELS SEEM A BIT OVERDONE WITH DEWPOINTS AND INSTABILITY. FEEL MORE LIKELY SCENARIO IS ACTIVITY WAITS FOR THE LOW LEVEL JET TO KICK IN AFTER 0Z BEFORE IT GETS GOING. OTHER ISSUE TODAY IS CLOUD COVER AND HIGH TEMPERATURES. INTERESTINGLY THE HRRR AND RAP ARE COMPLETE OPPOSITE OF EACH OTHER...GIVING AROUND A 20 DEGREE DIFFERENCE IN HIGHS...WITH THE RAP HAVING MORE STRATUS AND COOLER TEMPERATURES. THE GEM AND ECMWF SIDE CLOSER TO THE RAP...WITH THE NAM IN BETWEEN. SINCE THE AREAL COVERAGE OF LOW STRATUS IS CURRENTLY LESS THAN EXPECTED...DID GO AHEAD AND RAISE HIGHS SEVERAL DEGREES FOR TODAY IN OUR CENTRAL AND WEST. ALSO THE HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION...SO ONE WOULD THINK ITS SHORT RANGE FORECAST SHOULD BE SOMEWHAT RELIABLE...AND IT HAS CONSISTENTLY BEEN WARM FOR TODAY. LOWERED HIGHS A FEW IN THE EAST WHERE IT IS RAINING...AND WHERE STRATUS SHOULD INDEED HOLD IN FOR MUCH OF THE DAY. AGAIN THIS IS A PRETTY LOW CONFIDENCE TEMPERATURE FORECAST FOR ANYWHERE EAST OF THE JAMES RIVER. BUT FEEL GOING FORECAST IS A DECENT STARTING POINT...WITH THE DAY SHIFT LIKELY HAVING TO ADJUST UP OR DOWN DEPENDING ON CLOUD COVER TRENDS. QUIET SHORT TERM CONDITIONS FROM THE AFTERNOON HOURS SHOULD TURN QUICKLY TO MORE STORMY CONDITIONS OVERNIGHT. GAVE A FAIR AMOUNT OF CREDIT TO THE CONSISTENCY OF THE 00Z HIGH RESOLUTION NAMDNG5 AND WRF-ARW SOLUTIONS...WHICH FIT THE OVERALL CONCEPTUAL MODEL FOR CONVECTIVE INITIATION TONIGHT. BOUNDARY FROM CURRENT NIGHT MCS WILL BE FESTERING AND DRIFTING NORTHWARD...WITH LIKELY 1000 TO 1500 J/KG ELEVATED CAPE LIFTED FROM 1 TO 1.5 KM AGL. AS 35 TO 40 KNOT LOW LEVEL JET DEVELOPS TONIGHT THROUGH THE CENTRAL PLAINS... SHOULD BECOME ENOUGH TO INITIATE ELEVATED THUNDERSTORMS NEAR/NORTH OF THE BOUNDARY WHICH WILL BE DRIFTING NORTHWARD OF INTERSTATE 80 DURING THE EVENING HOURS. EFFECTIVE SHEAR IN AREAS NORTH OF THE BOUNDARY WILL BE VERY CONCENTRATED IN THE 1-3KM LAYER WITH STRONGEST WINDS IN LOW LEVELS AND WEAKENING MID LEVEL WINDS ROUGHLY 20-30 KNOTS...WITH LESSER DEEP LAYER SHEAR CONTRIBUTIONS FROM ABOVE. ALL SUGGEST AT LEAST A MINIMAL THREAT FOR ISOLATED LARGER HAIL OR DAMAGING WINDS THROUGH THE MISSOURI RIVER CORRIDOR AND LIFTING SOMEWHAT NORTHWARD THROUGH 066-08Z. OTHER SIGNIFICANT CONVECTIVE INITIATION IS LIKELY TO OCCUR BACK THROUGH THE WESTERN HIGH PLAINS WHERE STRONGER SHEAR EXISTS WITH A BIT STRONGER MID LEVEL WINDS TO AROUND 25 KNOTS...AS WELL AS THE DEEP UPSLOPE TRANSPORT OF MOISTURE TO RESULT IN STRONGER INSTABILITY. EVENTUALLY...WHEN SUPERCELL MOTIONS WHICH WILL TAKE ACTION MORE SOUTHWARD THAN EAST START TO EASE...AND LOW LEVEL JET VEERS EASTWARD...WILL FIND A MORE LINEAR MCS LIKELY TAKING SHAPE. MANY HI RES MODELS SUGGEST THIS MCS WILL ZIPPER DOWN THE LOCATION OF THE WARM ADVECTION WING SPREADING NORTHWARD...MOVING TOWARD EAST CENTRAL SD AND SOUTHWEST MN LATE NIGHT. SEVERE THREAT WITH THIS FEATURE WOULD SEEM TO BE SOMEWHAT LOWER...BUT LIKELY TO GET SOME GUSTY WINDS AND AREAS OF HEAVY RAINFALL. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 430 AM CDT SAT MAY 25 2013 MCS EXPECTED TO WEAKEN AND SHIFT EAST ON SUNDAY...AND WITH MID LEVEL FORCING SHOWING TENDENCY TO FORCE SUBSIDENCE AROUND MIDDAY...AGAIN EXPECT THAT MUCH OF THE DAYTIME PERIOD WILL PROBABLY END UP PRECIPITATION FREE. HOWEVER...CLOUDS LIKELY TO PERSIST WITH STRATUS DEVELOPING IN WAKE OF SYSTEM. MOST LIKELY TO GET BREAKS THROUGH THE WESTERN AND SOUTHERN CWA DURING THE AFTERNOON...AND HAVE PUSHED EXPECTED TEMPS TO NEAR 80 THERE... WHILE MORE MID TO UPPER 60S LINGER IN THE FAR EAST. RESULT OF THIS WILL BE GENERATION OF DECENT POTENTIAL INSTABILITY OF 1500-2000 J/KG ACROSS THE AREA...WITH WEAKEST OF THE CAPPING INVERSION NEAR THE MISSOURI RIVER CORRIDOR. SHEAR BECOMES A BIT MORE DISTRIBUTED THROUGH THE EFFECTIVE LAYER...AND FAIRLY CLOSE TO THOSE VALUES FROM THIS EVENING FROM 30 TO 35 KNOTS. A FEW MORE SEVERE STORMS WOULD BE POSSIBLE MAINLY THROUGH THE SOUTHWEST HALF OF THE AREA DURING THE LATER AFTERNOON AND EVENING HOURS...AS INITIATION LIKELY TO BE A RESULT OF WEAK IMPULSE SLIDING UP BACK SIDE OF RIDGE IN THE LATER AFTERNOON AND EARLY EVENING. THE FURTHER ONE GOES INTO THE FORECAST...THE LESS RELIABLE ANY GUIDANCE BECOMES GIVEN THE ABUNDANCE OF CONVECTION...AND THE INCREASINGLY GREAT UNCERTAINTY AS TO WHERE CRITICAL BOUNDARIES MAY LIE. ONE THING FOR SURE...GIVEN THE CLOSED LOW ACROSS THE WESTERN U.S. AND THE SOUTHWEST FLOW ALOFT...DIFFICULT TO PINPOINT ANY TIME FROM MONDAY ON THAT ONE COULD SAY THERE WAS ABSOLUTELY NO CHANCE FOR PRECIPITATION...BUT ON THE SAME FRONT IT CERTAINLY WILL NOT BE AN ALL TIME WASHOUT WITH MANY BREAKS DEFINED ON THE MESOSCALE. MEMORIAL DAY AND MONDAY NIGHT WILL PLACE THE AREA ON THE SOUTHERN FLANK OF A COUPLE OF WAVES MOVING OVER THE RIDGE...SO LIKELY TO HAVE ENHANCEMENT OF PRECIPITATION IN THE NOCTURNALLY FAVORED PERIODS. WHILE A FEW SEVERE STORMS ARE AGAIN WELL WITHIN REASON...HIGH PRECIPITABLE WATER AND FAIRLY SLOW MOVING WIND PROFILES BRING THE CONCERN OF AREAS OF HEAVY RAINFALL...AT THIS RANGE HARD TO DEFINE. AT THE MOMENT...THE PROSPECT FOR MORE SIGNIFICANT CONVECTION AND SEVERE WEATHER WOULD APPEAR TO BE LATE DAY WEDNESDAY INTO THURSDAY...AS DEEP WESTERN CLOSED LOW KICKS STRONGER JET ENERGY INTO THE PLAINS. MOISTURE THROUGH LOWER LEVELS /THUS INSTABILITY/ WILL CONTINUE TO BENEFIT FROM PERSISTENT SOUTHERLY FLOW. TEMPERATURES WILL LIKELY GRAVITATE TO SOMEWHAT ABOVE NORMAL READINGS THROUGH THE UPCOMING WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1239 PM CDT SAT MAY 25 2013 MVFR CIGS ACROSS SW MN AND NW IA DID ADVECT INTO THE FSD/SUX TAF SITES THIS MORNING WITH ESE LOW LEVEL FLOW IN PLACE. EXPECT MVFR CIGS TO CONTINUE THROUGH THIS AFTERNOON WITH THE EDGE RIGHT AT FSD POSSIBLY WAVERING...ALTHOUGH ADDITIONAL EXPANSION OF THIS STRATUS IS NOT EXPECTED TOWARD HON UNTIL LATER THIS EVENING. EXPECTING CONVECTION TO DEVELOP THIS EVENING ALONG THE WARM FRONT EXTENDING ACROSS SW SD AND NE NEBRASKA THEN PUSH EAST AND NORTHEAST ACROSS THE AREA LATE EVENING AND OVERNIGHT. IN ADDITION...LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE WITH ...RESULTING IN IFR CIGS WITH SOME AREAS OF HAZE LIKELY. BY EARLY MORNING /2Z/ CONVECTION SHOULD BE EXITING THE AREA...ALTHOUGH IFR/MVFR CIGS ARE EXPECTED TO PERSIST THROUGH MID MORNING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE... SHORT TERM...CHAPMAN/CHENARD LONG TERM...CHAPMAN AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
609 PM CDT SAT MAY 25 2013 .DISCUSSION...SEE 00Z AVIATION DISCUSSION. && .AVIATION...MVFR CONDITIONS ARE EXPECTED TO DEVELOP AGAIN AFTER SUNSET...STARTING AT KCRP AND KALI BETWEEN 03Z-04Z...THEN AT KVCT ABT 06Z...WITH MVFR CIGS AT KLRD BFR 12Z. VFR CONDITIONS SHOULD DEVELOP AOA 16Z AREA-WIDE. CONCERNING THUNDER/SHRA IN TAFS...ONLY HAVE THAT IN KVCT FOR NOW ENDING BY 03Z. THINK ANY OTHER CONVECTION TONIGHT WILL BE AWAY FROM TERMINALS...AND ANY WHICH MAY DEVELOP OVERNIGHT WILL BE TOO ISOLATED. CONCERNING WINDS... SOUTHEAST WINDS WILL TAPER OFF TONIGHT...WITH INCREASING WINDS WITH GUSTS AROUND 18Z...EXCEPT AT KLRD WHERE WINDS WILL BE SE WITH GUSTS LIMITED IF ANY. && .PREV DISCUSSION... /ISSUED 420 PM CDT SAT MAY 25 2013/ SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)...ACTIVE AFTERNOON WITH A WEAK PATTERN CONTINUES. GOOD CAPE...BUT MARGINAL LAPSE RATES AND WEAK SHEAR...BUT CONTINUE TO HAVE STORMS DEVELOP...A FEW PRODUCING BRIEF FUNNEL CLOUDS OR TORNADOES. FLOOD CONCERNS ARE DECREASING AS STORMS ARE MOVING BETTER THAN EARLIER IN THE DAY...AND NOT TRAINING. INITIAL VORT MAX CURRENTLY INTO NORTHEAST PORTIONS OF OUR FORECAST AREA BUT RUC GUIDANCE SHOWS ADDITIONAL VORT MAX COMING ACROSS OVERNIGHT. HAVE INCREASE POPS TO 30 OVERNIGHT...BUT SORT OF A HEDGE BET AT THIS POINT AS MESO MODELS ARENT SHOWING A WHOLE LOT. IF WE GET CONVECTION TO RE FIRE WITH THIS VORT MAX COULD BECOME ANOTHER MORE WIDE SPREAD EVENT OVERNIGHT. WILL KEEP ISOLATED SHOWERS AND STORMS IN THE FORECAST FOR TOMORROW AS WEAK SHORTWAVES CONTINUE TO AFFECT THE AREA. BY SUNDAY AFTERNOON THINGS SHOULD QUIET DOWN WITH PRECIP MOVING OUT OF THE AREA. COULD EVEN SEE SOME BREAKS IN THE CLOUDS BY THE AFTERNOON. MILD MIN TEMPS AND WARM HIGHS CONTINUE. LONG TERM...(MONDAY THROUGH FRIDAY)...DID NOT MAKE MANY CHANGES TO THE EXTENDED PART OF THE FORECAST. UPPER LEVEL RIDGE WILL BUILD IN FOR MONDAY WITH DRIER AIR ACROSS THE AREA. TEMPERATURES WILL REBOUND FOR THE EARLY PART OF THE WEEK WITH UPPER 90S OUT WEST TO UPPER 80S OVER THE VICTORIA CROSSROADS. RIDGE WILL BEGIN TO SHIFT EASTWARD TUESDAY INTO WEDNESDAY. MODELS NOW INDICATE UPPER TROUGH MOVING INTO THE FOUR CORNERS WEDNESDAY AND INTO THE PLAINS WEDNESDAY NIGHT. MOISTURE DOES INCREASE BY WEDNESDAY OVER THE RIO GRANDE PLAINS BUT BELIEVE ATMOSPHERE MAY BE CAPPED...SO WILL CONTINUE WITH POPS BELOW MENTIONABLE LEVELS. LEFT INHERITED LOW END POPS IN FOR THURSDAY FOR THE TIME BEING...BUT CAPPING COULD BE AN ISSUE THIS DAY AS WELL. ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE EXTENDED. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 76 89 73 88 75 / 20 20 10 10 10 VICTORIA 73 89 71 88 73 / 20 20 10 10 10 LAREDO 76 93 76 97 75 / 20 20 10 10 10 ALICE 72 90 72 91 74 / 20 20 10 10 10 ROCKPORT 76 86 76 86 76 / 20 20 10 10 10 COTULLA 72 92 72 93 73 / 20 20 10 10 10 KINGSVILLE 74 90 73 90 75 / 20 20 10 10 10 NAVY CORPUS 76 85 76 86 77 / 20 20 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
420 PM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)...ACTIVE AFTERNOON WITH A WEAK PATTERN CONTINUES. GOOD CAPE...BUT MARGINAL LAPSE RATES AND WEAK SHEAR...BUT CONTINUE TO HAVE STORMS DEVELOP...A FEW PRODUCING BRIEF FUNNEL CLOUDS OR TORNADOES. FLOOD CONCERNS ARE DECREASING AS STORMS ARE MOVING BETTER THAN EARLIER IN THE DAY...AND NOT TRAINING. INITIAL VORT MAX CURRENTLY INTO NORTHEAST PORTIONS OF OUR FORECAST AREA BUT RUC GUIDANCE SHOWS ADDITIONAL VORT MAX COMING ACROSS OVERNIGHT. HAVE INCREASE POPS TO 30 OVERNIGHT...BUT SORT OF A HEDGE BET AT THIS POINT AS MESO MODELS ARENT SHOWING A WHOLE LOT. IF WE GET CONVECTION TO RE FIRE WITH THIS VORT MAX COULD BECOME ANOTHER MORE WIDE SPREAD EVENT OVERNIGHT. WILL KEEP ISOLATED SHOWERS AND STORMS IN THE FORECAST FOR TOMORROW AS WEAK SHORTWAVES CONTINUE TO AFFECT THE AREA. BY SUNDAY AFTERNOON THINGS SHOULD QUIET DOWN WITH PRECIP MOVING OUT OF THE AREA. COULD EVEN SEE SOME BREAKS IN THE CLOUDS BY THE AFTERNOON. MILD MIN TEMPS AND WARM HIGHS CONTINUE. && .LONG TERM...(MONDAY THROUGH FRIDAY)...DID NOT MAKE MANY CHANGES TO THE EXTENDED PART OF THE FORECAST. UPPER LEVEL RIDGE WILL BUILD IN FOR MONDAY WITH DRIER AIR ACROSS THE AREA. TEMPERATURES WILL REBOUND FOR THE EARLY PART OF THE WEEK WITH UPPER 90S OUT WEST TO UPPER 80S OVER THE VICTORIA CROSSROADS. RIDGE WILL BEGIN TO SHIFT EASTWARD TUESDAY INTO WEDNESDAY. MODELS NOW INDICATE UPPER TROUGH MOVING INTO THE FOUR CORNERS WEDNESDAY AND INTO THE PLAINS WEDNESDAY NIGHT. MOISTURE DOES INCREASE BY WEDNESDAY OVER THE RIO GRANDE PLAINS BUT BELIEVE ATMOSPHERE MAY BE CAPPED...SO WILL CONTINUE WITH POPS BELOW MENTIONABLE LEVELS. LEFT INHERITED LOW END POPS IN FOR THURSDAY FOR THE TIME BEING...BUT CAPPING COULD BE AN ISSUE THIS DAY AS WELL. ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE EXTENDED. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 76 89 73 88 75 / 20 20 10 10 10 VICTORIA 73 89 71 88 73 / 20 20 10 10 10 LAREDO 76 93 76 97 75 / 20 20 10 10 10 ALICE 72 90 72 91 74 / 20 20 10 10 10 ROCKPORT 76 86 76 86 76 / 20 20 10 10 10 COTULLA 72 92 72 93 73 / 20 20 10 10 10 KINGSVILLE 74 90 73 90 75 / 20 20 10 10 10 NAVY CORPUS 76 85 76 86 77 / 20 20 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ PZ/83...SHORT TERM TB/78...LONG TERM
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
414 PM CDT SAT MAY 25 2013 .DISCUSSION... THROUGH TONIGHT...LEFT THE EARLY AFTERNOON UPDATE FORECAST DISCUSSION ATTACHED BELOW FOR REFERENCE AND MORE DETAILS ON THE SHORT TERM FORECAST CONCERNS. CHANGES FROM EARLIER DISCUSSION...THE MCV THAT WAS EXPECTED TO DEVELOP NEAR SAN ANTONIO WAS APPARENT IN REGIONAL RADAR RETURNS NEAR AUSTIN AND GONZALEZ AT THE TIME OF THIS DISCUSSION. ASSUMING THAT THIS IS THE PRIMARY MID-LEVEL LOW/MCV PRODUCED BY THE PERSISTENT SAN ANTONIO AREA CONVECTION THIS MORNING...ADJUSTED RAIN CHANCES THIS EVENING AND OVERNIGHT IN LINE WITH ITS EXPECTED TRAJECTORY. THE 19Z RUN OF THE RAP SEEMS TO HAVE A GOOD HANDLE ON THE POSITION OF THIS MCV...SO GENERALLY USED THIS MODEL FOR GUIDANCE OVER THE NEXT 12 TO 18 HRS. THE MCV IS EXPECTED TO MOVE GENERALLY IN A NORTHEASTERLY DIRECTION THROUGH TONIGHT...TAKING IT FROM ITS CURRENT LOCATION TO JUST NORTHEAST OF TYLER BY SUNRISE SUNDAY. THE GFS INDICATES THAT THE UPPER TROUGH THAT WAS ANALYZED IN THE 12Z RAOB ANALYSIS TO THE WEST OF THE CWA WILL INTERACT WITH THIS MCV FAVORABLY AND RESULT IN WIDESPREAD THUNDERSTORM ACTIVITY GENERALLY EAST OF I-35 AND SOUTH OF I-20 AFTER MIDNIGHT...SPREADING NORTHEAST INTO THE ARKLATEX AREA JUST AFTER SUNRISE. BOTH OF THESE FEATURES EXIST...SO THIS SOLUTION IS VIABLE...HOWEVER THE FORCING FOR ASCENT ADVERTISED BY THE GFS IS GREATLY ENHANCED BY CONVECTIVE FEEDBACK. THAT IS...MODEL GENERATED STORMS COOL OFF LOCATIONS DOWNSTREAM /NORTHEAST/ ALLOWING WARM AIR ADVECTION TO ARTIFICIALLY RAMP UP RESULTING IN THE GENERATION OF MORE STORMS. IN SHORT...A MODEL GENERATED FEEDBACK LOOP. THIS LOOP MAY VERIFY AND RESULT IN A HEAVY RAINFALL EVENT EAST OF I-35 TO THE ARKLATEX AREA TONIGHT THROUGH SUNDAY MORNING. HOWEVER THERE IS NOT REALLY ANY HIGH RESOLUTION MODEL OUTPUT SUPPORT FOR THIS SOLUTION AT THIS TIME...THEREFORE CONFIDENCE IS SOMEWHAT LOW IN A WIDESPREAD HEAVY RAIN EVENT. THAT SAID...MANY FACTORS ARE IN PLACE TO SUPPORT A LOCALIZED HEAVY RAINFALL EVENT ANYWHERE STORMS EXIST OVER THE NEXT 12 TO 18 HRS. PRECIPITABLE WATER VALUES ARE ABOVE THE 75TH PERCENTILE OF HISTORICAL PRECIPITABLE WATER VALUES FOR THIS REGION IN LATE MAY. MID-LEVEL LAPSE RATES ARE POOR BUT THE ENVIRONMENT IS UNCAPPED...IN SHORT A FAVORABLE ENVIRONMENT FOR VERY TALL RAIN SHOWERS WITH LITTLE LIGHTNING ACTIVITY AND ONLY WEAK GENERATION OF OUTFLOW BOUNDARIES. WEAK OUTFLOW MEANS THAT STORMS CAN REMAIN IN ONE PLACE FOR A LONGER PERIOD OF TIME INCREASING THE CHANCES FOR TRAINING OF STORMS AND A LOCALIZED FLOODING THREAT. AT THIS TIME WENT WITH A MENTION OF LOCALIZED HEAVY RAIN AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK AND WORDED FORECAST. WITH WEAK WIND SHEAR IN THIS THERMODYNAMIC ENVIRONMENT STORMS ARE EXPECTED TO BEHAVE IN A NEARLY TROPICAL NATURE WITH EFFICIENT RAINFALL PRODUCTION. THEREFORE CHANCES OF SEVERE WEATHER APPEAR TO BE VERY SMALL TONIGHT. WE WILL HAVE TO KEEP A CLOSE EYE ON THE EVOLUTION OF A LOCALIZED FLOODING EVENT...ESPECIALLY WITH MANY PEOPLE LIKELY CAMPING OUTDOORS IN FLOOD PRONE AREAS THROUGH TONIGHT. SUNDAY...SUNDAY MORNING WE WILL LIKELY HAVE SOME REMNANT POCKETS OF HEAVY RAIN ALONG A SULPHUR SPRINGS TO PALESTINE LINE...LIKELY MOVING NORTHEAST TOWARDS THE ARKLATEX REGION THROUGHOUT THE MORNING HOURS. FROM THE WEST...THE HRRR HAS CONSISTENTLY INDICATED THAT A SQUALL LINE WILL ORGANIZE OVER THE SOUTHERN HIGH PLAINS/TX PANHANDLE TONIGHT AND MOVE EAST TOWARDS OUR WESTERN CWA EARLY SUNDAY MORNING. WE WILL HAVE TO KEEP AN EYE ON THIS...NOT SO MUCH FROM A SEVERE WEATHER STAND POINT BUT FROM ANOTHER POTENTIAL SOURCE FOR MCV PRODUCTION. WITH THE SAN ANTONIO AREA MCV AND LARGER UPPER TROUGH MOVING EAST...SUBSIDENCE WILL LIKELY DOMINATE ANY MCV MOVING OFF THE HIGH PLAINS AND THRU NORTH TX TOMORROW. HOWEVER UNTIL WE GET SOME DRIER AIR IN OVER THE REGION CAPPING OFF THE ATMOSPHERE FOR THUNDERSTORM DEVELOPMENT...WILL HOLD ON TO A BROAD BRUSHED MENTION OF SHOWERS AND THUNDERSTORMS IN THE FORECAST ACROSS ALL OF NORTH TX THROUGH SUNDAY. NEXT WEEK...BEGINNING MONDAY A WESTERN CONUS TROUGH IS EXPECTED TO ORGANIZE SENDING THE WEAK UPPER LEVEL RIDGE AND ENTRAPPED MCV FEATURES OFF TO THE EAST OF THE REGION. THIS IS EXPECTED TO RESULT IN SOUTHWEST FLOW ALOFT OVER NORTH TX ON MONDAY WHICH SHOULD HELP TO ADVECT A RELATIVELY STOUT CAP IN PLACE OVER THE REGION BY MONDAY AFTERNOON. THIS CAP IS EXPECTED TO HOLD IN PLACE THROUGH THE WEEK UNLESS THE DRYLINE OR A STRONG SHORTWAVE TROUGH CAN LIFT THE CAP AND RESULT IN THUNDERSTORM INITIATION DURING THE WEEK AHEAD. WE ARE EXPECTED TO HAVE RELATIVELY PERSISTENT...BREEZY SOUTH WINDS IN PLACE BELOW THE CAP THROUGH THE WEEK. THIS WILL HELP KEEP GOOD GULF MOISTURE IN PLACE UNDER THE CAP PROVIDING PLENTY OF POSITIVE CAPE FOR THUNDERSTORM DEVELOPMENT IF ANYTHING CAN REMOVE THE CAP. WITHOUT STORMS...WE WILL LIKELY SEE HIGHS HOLD IN THE UPPER 80S WITH LOWS IN THE LOWER TO MID 70S EACH DAY. THE GFS AND ECMWF BOTH INDICATE THAT A STRONG SHORTWAVE TROUGH WILL MOVE OVER THE SOUTH PLAINS WEDNESDAY THROUGH WEDNESDAY EVENING. THE ECMWF REMAINS FURTHER SOUTH WITH THIS TROUGH WHICH IS WHAT WE WILL NEED TO LIFT THE CAP AND RESULT IN STORMS ACROSS THE CWA WEDNESDAY AFTERNOON AND EVENING. THE GFS INDICATES THE BEST FORCING STAYS NORTH OF THE CWA. WENT AHEAD WITH 20 TO 30 POPS WEST OF INTERSTATE 35...CLOSEST TO THE UPPER TROUGH WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS RESULT. REMOVED POPS THEREAFTER WITH ALL GUIDANCE INDICATING SUBSIDENCE BEHIND THIS UPPER TROUGH ON THURSDAY. CAVANAUGH && .PREV UPDATE FOR SHORT TERM FORECAST... THE PRIMARY FORECAST CHALLENGE FOR THE NEXT 24 HRS IS DETERMINING WHERE AND WHEN A MID-LEVEL LOW PRESSURE SYSTEM /MCV...CAUSED BY PERSISTENT THUNDERSTORM ACTIVITY THAT HAS DISSIPATED/ WILL MOVE OVER NORTH TX AND BRING US MORE THUNDERSTORM ACTIVITY. THE MID- LEVEL LOW FROM YESTERDAYS THUNDERSTORM ACTIVITY WAS DIFFICULT TO LOCATE THIS MORNING. 12Z UPPER AIR ANALYSIS INDICATED MID-LEVEL CYCLONIC CIRCULATIONS FROM NORTHWEST TX SOUTH TO THE HILL COUNTRY. IT IS POSSIBLE THAT THIS CYCLONIC SHEAR AXIS IS YESTERDAYS MID- LEVEL LOW...BUT SHEARED APART IN THE LARGER SCALE UPPER LEVEL RIDGE OVER THE REGION. JUST BEFORE NOON...THERE WAS A BAND OF RAIN SHOWERS AND EMBEDDED STORMS EXTENDING FROM STEPHENVILLE SOUTH TO THE AUSTIN AND SAN ANTONIO AREAS WHICH APPEARED TO BE ASSOCIATED WITH THIS SHEAR AXIS. THE MORE INTENSE THUNDERSTORMS AND RAIN SHOWERS WERE LOCATED AT THE FAR SOUTHERN END OF THIS LINE...CAUSING WIDESPREAD FLOODING AROUND THE CITY OF SAN ANTONIO AT THE TIME OF THIS DISCUSSION. DUE TO THE PERSISTENCE OF INTENSE RAIN SHOWER AND THUNDERSTORM ACTIVITY TO THE SOUTH OF THE CWA...WOULD EXPECT THAT A NEW OR REINFORCED MID-LEVEL LOW PRESSURE SYSTEM WOULD DEVELOP AROUND SAN ANTONIO SOMETIME TODAY. THERE HAS BEEN SOME INDICATION OF WEAK CYCLONIC CIRCULATIONS IN THE LIGHTER RAINFALL RETURNS TO THE NORTH OF SAN ANTONIO...IN BETWEEN TEMPLE AND AUSTIN. MID-LEVEL LOW PRESSURE SYSTEMS ARE CREATED BY THUNDERSTORMS DUE TO LARGE AMOUNTS OF LATENT HEAT RELEASED IN THE MIDDLE OF THE ATMOSPHERE DUE TO WATER VAPOR CONDENSING INTO WATER DROPLETS OR RAIN. BECAUSE THIS HAS BEEN GOING ON IN AN INTENSE FASHION NEAR SAN ANTONIO ALL MORNING...THINK THAT A MID-LEVEL LOW PRESSURE SYSTEM WILL LIKELY DEVELOP AROUND SAN ANTONIO /IF IT HAS NOT ALREADY/ AND BECOME THE DOMINANT MESOSCALE FEATURE DRIVING RAIN AND STORM CHANCES FOR NORTH TX OVER THE NEXT 24 HRS. THROUGH THIS AFTERNOON JUST ADJUSTED POPS TO HIGHLIGHT AREAS SOUTH OF INTERSTATE 20 AS HAVING THE HIGHEST RAIN CHANCES TODAY ASSUMING THE SAN ANTONIO LOW MOVES SLIGHTLY EAST THROUGH 7 PM. DID NOT REMOVE RAIN CHANCES TO THE NORTH BECAUSE THE WEAK CYCLONIC SHEAR AXIS STILL EXISTS AS FAR NORTH AS WICHITA FALLS...SO SOME RAIN AND THUNDERSTORM CHANCES ARE STILL WARRANTED NORTH OF INTERSTATE 20 THIS AFTERNOON. SEVERE WEATHER CHANCES REMAIN SMALL ACROSS ALL OF NORTH TX AS MID-LEVEL LAPSE RATES ARE POOR DUE TO YESTERDAYS THUNDERSTORM ACTIVITY AND DEEP LAYER SHEAR REMAINS WEAK AT THIS TIME. CAVANAUGH && .AVIATION... /18Z TAFS/ CONCERNS...THUNDER THROUGH THE EVENING AND MVFR CIGS THROUGH THE PERIOD. A MESSY TAF PERIOD CONTINUES WITH LOW CONFIDENCE IN CLOUD AND PRECIPITATION TRENDS FOR THE NEXT 18-24 HOURS. AT ALL THE TAF AIRPORTS...SCATTERED TO BROKEN MVFR CIGS WITH BASES BETWEEN 1200-2000 FEET PERSIST. HOWEVER...IFR CIGS ARE BEING REPORTED SOUTHWEST OF KACT WHERE LIGHT RAIN HAS PERSISTED FOR MUCH OF THE MORNING. CEILINGS SHOULD LIFT ABOVE 2000 FEET THIS AFTERNOON AND POSSIBLY INTO VFR CATEGORY BEFORE THE EVENING HOURS BUT THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS IN THE REGION MAY AFFECT IMPROVING CLOUD TRENDS. MOST OF THE PRECIPITATION THIS MORNING HAS REMAINED WEST OF THE AIRPORTS BUT RADAR INDICATES NEW DEVELOPMENT CLOSER TO THE TAF TERMINALS. EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP THROUGHOUT THE AFTERNOON. SHOWERS AND THUNDERSTORMS COULD DIRECTLY IMPACT ANY OF THE AIRPORTS THIS AFTERNOON BUT THINK KACT AS THE HIGHEST CHANCES OF BEING IMPACTS BY CONVECTION AND INCLUDED A TEMPO FROM 19-23Z FOR TSRA. ONCE AGAIN...EXPECT MOST OF THE CONVECTIVE ACTIVITY TO DECREASE THIS AFTERNOON AND A FAIRLY QUIET AND DRY OVERNIGHT PERIOD...BUT WILL BE MONITORING THE MOVEMENT OF AN UPPER LEVEL LOW OVER THE REGION FOR ANY CHANGES TO RAIN/CONVECTIVE CHANCES. ALSO WILL BE MONITORING FOR ANOTHER AREA OF WIDESPREAD RAIN/STORMS TO AFFECT ANY OF THE AIRPORTS LATER TODAY. MVFR CIGS WILL LIKELY RETURN TO ALL TAF AIRPORTS OVERNIGHT BETWEEN 09-11Z. 82/JLD && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 69 87 69 87 70 / 30 10 5 0 0 WACO, TX 68 87 68 89 71 / 30 10 5 0 0 PARIS, TX 67 85 66 85 67 / 30 10 5 0 0 DENTON, TX 67 86 68 87 68 / 30 10 5 0 0 MCKINNEY, TX 67 85 68 87 69 / 30 10 5 0 0 DALLAS, TX 71 87 70 89 72 / 30 10 5 0 0 TERRELL, TX 67 86 68 88 70 / 30 10 5 0 0 CORSICANA, TX 67 88 68 89 70 / 30 10 5 0 0 TEMPLE, TX 67 87 68 88 70 / 20 10 5 0 0 MINERAL WELLS, TX 66 87 67 89 68 / 20 10 5 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
339 PM CDT SAT MAY 25 2013 .SHORT TERM... MOIST UPSLOPE FLOW ACROSS EASTERN NEW MEXICO HAS ALREADY SUPPORTED SCATTERED TSTMS FROM THE SACRAMENTOS NORTH TO SANTA ROSA. A SECOND AREA OF INTEREST IS EVIDENT ON VIS SATELLITE ALONG THE MESCALERO ESCARPMENT WHERE AGITATED CU HAVE RECENTLY DEVELOPED. HRRR AND NAM-WRF BOTH PROG TSTM DEVELOPMENT ALONG THIS CU LINE BEFORE 00Z AND CARRY IT EASTWARD TO VARIOUS DEGREES WITHIN 20 KNOTS OF 700-500MB FLOW. CONSIDERING CINH IS TRENDING NEGLIGIBLE ALONG THE NM/TX STATE LINE AND SBCAPE IS AROUND 2K J/KG...HAVE ADDED SEVERE MENTION TO OUR WESTERNMOST COUNTIES WHERE THIS ACTIVITY WILL LIKELY PEAK IN INTENSITY BEFORE DIMINISHING THEREAFTER AS THE MIXING LAYER DECOUPLES. LITTLE/NO BACKGROUND SUPPORT MAY FURTHER LIMIT THE CHANCES OF THIS PERSISTING OVER THE REMAINDER OF THE SOUTH PLAINS...BUT WILL KEEP SOME ISOLATED MENTION THROUGH 06Z. SUNDAY WILL SEE IMPROVED W-SWLY FLOW OVERSPREAD THE REGION RESULTING IN THE DRYLINE MIXING OUT OF NEW MEXICO AND STALLING SOMEWHERE OVER THE WESTERN 1/3 OF THE CWA. ALBEIT MODEST...AN ADDITIONAL INFLUX OF GULF MOISTURE BY EARLY SUNDAY IS PROGGED TO SECURE HIGHER SBCAPES GENERALLY AROUND 3500 J/KG ALONG THE DRYLINE WITH EVEN EXTREME VALUES IN THE ROLLING PLAINS...HOWEVER THE LATTER IS SHOWN TO REMAIN CAPPED AND TOO FAR REMOVED FROM THE DRYLINE. NO DISCERNIBLE SHORT WAVE TROUGHS ARE PROGGED...BUT AS IS THE CASE TODAY DEEP MIXING SHOULD PROVE MORE THAN ADEQUATE FOR AT LEAST ISO TSTMS. WINDOW FOR SUPERCELLS WILL BE OPENED 0-6KM BULK SHEAR VECTORS RISE TO NEARLY 40 KNOTS AND MAINTAIN A PERPENDICULAR ORIENTATION TO THE DRYLINE. ROBUST CAPE IN THE HAIL GROWTH LAYER COMBINED WITH RELATIVELY HIGH LCL VALUES WILL OPEN THE WINDOW FOR SOME VERY LARGE HAIL AND DMGG DOWNBURSTS. MOST HIGH TEMPS WERE KEPT A FEW DEGREES ABOVE MOS...PARTICULARLY WEST OF THE DRYLINE WHERE OUR HIGHEST ELEVATIONS COULD END UP WITH THE HOTTEST VALUES FOR THE DAY. && .LONG TERM... HIGH AMPLITUDE RIDGE ORIENTED FROM THE BIG BEND TO THE WESTERN GREAT LAKES THENCE WELL INTO CENTRAL CANADA WILL CONTINUE ITS SLOW EASTWARD PROGRESSION AS A COUPLE OF STORM SYSTEMS COME ASHORE THE PACIFIC NORTHWEST. TOWARD MID WEEK...FLOW ACROSS WEST TEXAS WILL STRENGTHEN AS NEGATIVELY TILTED TROUGH DEEPENS FROM THE PAC NW. THURSDAY SHOULD SEE A RETURN TO ZONAL FLOW AS UPPER LOW SETTLES ACROSS WYOMING THOUGH ANOTHER LOBE OF ENERGY ROTATING AROUND THE WY SYSTEM WILL APPROACH LATE THU/EARLY FRIDAY WITH SOUTHWESTERLIES PERSISTING THROUGH DAY 7. WILL CONTINUE MENTION OF TSRA INTO THE EVENING HOURS ON SUNDAY WITH CONDITIONS SETTLING AFTER SUNSET. DRYLINE SHOULD PUSH INTO NEW MEXICO OVERNIGHT THEN TIGHTEN UP AGAIN MONDAY AFTERNOON WITH CONVECTION LOOKING MOST LIKELY EAST OF A SILVERTON TO BROWNFIELD LINE THOUGH SOME VARIANCE WILL BE POSSIBLE GIVEN THE INFLUENCES OF SUNDAY NIGHT/S STORMS. WEDNESDAY LOOKS TO KEEP THE DRYLINE A BIT FURTHER WEST THUS GIVING MORE OF THE AREA A SHOT AT THE MUCH NEEDED RAINFALL. WITH THE MORE STRONGLY DIFLUENT FLOW ON WEDNESDAY...THIS COULD BE THE MOST PRONOUNCED OF THE SEVERE WEATHER THIS WEEK THOUGH EACH DAY WILL HAVE SEVERE POTENTIAL. THE LONG AND SHORT OF IT IS THAT EACH DAY OVER THE NEXT WEEK...WE WILL SEE AT LEAST SCATTERED CONVECTION POTENTIAL EACH AFTERNOON AS THE DRYLINE SLOSHES ACROSS THE REGION. AT PRESENT...IT WOULD APPEAR THE TORNADO THREAT THIS WEEK WOULD BE MAXIMIZED ACROSS THE NORTHEASTERN ZONES ON WEDNESDAY. TO THE WEST OF THE DRYLINE...ELEVATED TO LOW END CRITICAL FIRE WEATHER CONDITIONS WILL EXIST NEARLY EVERY AFTERNOON AS MIN AFTN RH DROPS TO THE LOWER TEENS WITH THE BREEZY WEST-OF-THE-DRYLINE WINDS. OUR NORTHWEST HAS SEEN THE LOWEST AMOUNT OF GREEN-UP DUE TO THE LACK OF PRECIPITATION THIS SPRING AND WHILE FUELS ARE NOT PLENTIFUL...WHAT IS THERE WOULD BE EXPECTED TO BURN QUITE EASILY GIVEN THE RIGHT METEOROLOGICAL CONDITIONS. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 61 94 62 94 61 / 30 20 20 10 10 TULIA 61 94 65 94 64 / 20 20 20 20 20 PLAINVIEW 62 93 65 95 65 / 20 20 20 20 20 LEVELLAND 63 95 68 95 67 / 20 20 20 20 20 LUBBOCK 65 94 67 95 67 / 20 20 20 20 20 DENVER CITY 62 95 68 95 68 / 20 10 10 10 20 BROWNFIELD 63 95 68 96 68 / 20 20 20 20 20 CHILDRESS 68 94 67 94 67 / 10 10 10 10 20 SPUR 65 92 68 95 68 / 10 10 10 10 20 ASPERMONT 68 93 69 92 69 / 10 10 10 10 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 93/26
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1247 PM CDT SAT MAY 25 2013 .AVIATION... /18Z TAFS/ CONCERNS...THUNDER THROUGH THE EVENING AND MVFR CIGS THROUGH THE PERIOD. A MESSY TAF PERIOD CONTINUES WITH LOW CONFIDENCE IN CLOUD AND PRECIPITATION TRENDS FOR THE NEXT 18-24 HOURS. AT ALL THE TAF AIRPORTS...SCATTERED TO BROKEN MVFR CIGS WITH BASES BETWEEN 1200-2000 FEET PERSIST. HOWEVER...IFR CIGS ARE BEING REPORTED SOUTHWEST OF KACT WHERE LIGHT RAIN HAS PERSISTED FOR MUCH OF THE MORNING. CEILINGS SHOULD LIFT ABOVE 2000 FEET THIS AFTERNOON AND POSSIBLY INTO VFR CATEGORY BEFORE THE EVENING HOURS BUT THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS IN THE REGION MAY AFFECT IMPROVING CLOUD TRENDS. MOST OF THE PRECIPITATION THIS MORNING HAS REMAINED WEST OF THE AIRPORTS BUT RADAR INDICATES NEW DEVELOPMENT CLOSER TO THE TAF TERMINALS. EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP THROUGHOUT THE AFTERNOON. SHOWERS AND THUNDERSTORMS COULD DIRECTLY IMPACT ANY OF THE AIRPORTS THIS AFTERNOON BUT THINK KACT AS THE HIGHEST CHANCES OF BEING IMPACTS BY CONVECTION AND INCLUDED A TEMPO FROM 19-23Z FOR TSRA. ONCE AGAIN...EXPECT MOST OF THE CONVECTIVE ACTIVITY TO DECREASE THIS AFTERNOON AND A FAIRLY QUIET AND DRY OVERNIGHT PERIOD...BUT WILL BE MONITORING THE MOVEMENT OF AN UPPER LEVEL LOW OVER THE REGION FOR ANY CHANGES TO RAIN/CONVECTIVE CHANCES. ALSO WILL BE MONITORING FOR ANOTHER AREA OF WIDESPREAD RAIN/STORMS TO AFFECT ANY OF THE AIRPORTS LATER TODAY. MVFR CIGS WILL LIKELY RETURN TO ALL TAF AIRPORTS OVERNIGHT BETWEEN 09-11Z. 82/JLD && .UPDATE... THE PRIMARY FORECAST CHALLENGE FOR THE NEXT 24 HRS IS DETERMINING WHERE AND WHEN A MID-LEVEL LOW PRESSURE SYSTEM /MCV...CAUSED BY PERSISTENT THUNDERSTORM ACTIVITY THAT HAS DISSIPATED/ WILL MOVE OVER NORTH TX AND BRING US MORE THUNDERSTORM ACTIVITY. THE MID- LEVEL LOW FROM YESTERDAYS THUNDERSTORM ACTIVITY WAS DIFFICULT TO LOCATE THIS MORNING. 12Z UPPER AIR ANALYSIS INDICATED MID-LEVEL CYCLONIC CIRCULATIONS FROM NORTHWEST TX SOUTH TO THE HILL COUNTRY. IT IS POSSIBLE THAT THIS CYCLONIC SHEAR AXIS IS YESTERDAYS MID- LEVEL LOW...BUT SHEARED APART IN THE LARGER SCALE UPPER LEVEL RIDGE OVER THE REGION. JUST BEFORE NOON...THERE WAS A BAND OF RAIN SHOWERS AND EMBEDDED STORMS EXTENDING FROM STEPHENVILLE SOUTH TO THE AUSTIN AND SAN ANTONIO AREAS WHICH APPEARED TO BE ASSOCIATED WITH THIS SHEAR AXIS. THE MORE INTENSE THUNDERSTORMS AND RAIN SHOWERS WERE LOCATED AT THE FAR SOUTHERN END OF THIS LINE...CAUSING WIDESPREAD FLOODING AROUND THE CITY OF SAN ANTONIO AT THE TIME OF THIS DISCUSSION. DUE TO THE PERSISTENCE OF INTENSE RAIN SHOWER AND THUNDERSTORM ACTIVITY TO THE SOUTH OF THE CWA...WOULD EXPECT THAT A NEW OR REINFORCED MID-LEVEL LOW PRESSURE SYSTEM WOULD DEVELOP AROUND SAN ANTONIO SOMETIME TODAY. THERE HAS BEEN SOME INDICATION OF WEAK CYCLONIC CIRCULATIONS IN THE LIGHTER RAINFALL RETURNS TO THE NORTH OF SAN ANTONIO...IN BETWEEN TEMPLE AND AUSTIN. MID-LEVEL LOW PRESSURE SYSTEMS ARE CREATED BY THUNDERSTORMS DUE TO LARGE AMOUNTS OF LATENT HEAT RELEASED IN THE MIDDLE OF THE ATMOSPHERE DUE TO WATER VAPOR CONDENSING INTO WATER DROPLETS OR RAIN. BECAUSE THIS HAS BEEN GOING ON IN AN INTENSE FASHION NEAR SAN ANTONIO ALL MORNING...THINK THAT A MID-LEVEL LOW PRESSURE SYSTEM WILL LIKELY DEVELOP AROUND SAN ANTONIO /IF IT HAS NOT ALREADY/ AND BECOME THE DOMINANT MESOSCALE FEATURE DRIVING RAIN AND STORM CHANCES FOR NORTH TX OVER THE NEXT 24 HRS. THROUGH THIS AFTERNOON JUST ADJUSTED POPS TO HIGHLIGHT AREAS SOUTH OF INTERSTATE 20 AS HAVING THE HIGHEST RAIN CHANCES TODAY ASSUMING THE SAN ANTONIO LOW MOVES SLIGHTLY EAST THROUGH 7 PM. DID NOT REMOVE RAIN CHANCES TO THE NORTH BECAUSE THE WEAK CYCLONIC SHEAR AXIS STILL EXISTS AS FAR NORTH AS WICHITA FALLS...SO SOME RAIN AND THUNDERSTORM CHANCES ARE STILL WARRANTED NORTH OF INTERSTATE 20 THIS AFTERNOON. SEVERE WEATHER CHANCES REMAIN SMALL ACROSS ALL OF NORTH TX AS MID-LEVEL LAPSE RATES ARE POOR DUE TO YESTERDAYS THUNDERSTORM ACTIVITY AND DEEP LAYER SHEAR REMAINS WEAK AT THIS TIME. CAVANAUGH && .PREV DISCUSSION... /ISSUED 347 AM CDT SAT MAY 25 2013/ RADAR/SATELLITE LOOP INDICATES THAT THE WEAK MID LEVEL LOW IS LIKELY LOCATED NEAR ABILENE AND 00Z 500MB ANALYSIS CONFIRMS IT IS WARM-CORE IN NATURE. AS IS OFTEN THE CASE WITH WARM-CORE LOWS...CONVECTION IS FIRING BEFORE SUNRISE ACROSS THE HILL COUNTRY WITHIN A WEAK LOW LEVEL JET AXIS WHERE THETA-E ADVECTION AND OROGRAPHIC LIFT ARE OCCURRING. SHORT-TERM MODELS SUCH AS THE HRRR AND RUC SUGGEST THAT SCATTERED CONVECTION WILL CONTINUE TO EXPAND NORTHWARD FROM CENTRAL TEXAS INTO THE WESTERN ZONES DURING THE MORNING HOURS. THE GFS APPEARS TO BE SUFFERING FROM GRID SCALE CONVECTIVE FEEDBACK WHICH IS RESULTING IN VERY HIGH QPF AND CONTAMINATED MASS FIELDS...THUS THE GFS WILL NOT BE USED IN THE SHORT-TERM. THE NAM SEEMS TO BE MATCHING CURRENT TRENDS AND SHORT- TERM MODELS WELL AND THEREFORE IT GIVES CONFIDENCE TO RAISE POPS TODAY. WE EXPECT THE BEST COVERAGE OF CONVECTION IN THE WESTERN ZONES THIS MORNING. SCATTERED CONVECTION WILL BUILD/EXPAND EASTWARD INTO THE EASTERN ZONES DURING THE MIDDAY/AFTERNOON HOURS. THE AIRMASS OVER THE EASTERN ZONES WILL BE A BIT MORE UNSTABLE DUE TO BETTER INSOLATION AND A COUPLE OF STRONG STORMS WITH GUSTY WINDS WILL BE POSSIBLE...BUT DUE TO WEAK SHEAR THE SEVERE THREAT IS LOW. HIGHS TODAY IN THE WESTERN ZONES WILL ONLY BE IN THE UPPER 70S TO LOW 80S DUE TO CLOUDS/RAIN...WITH HIGHS IN THE EASTERN ZONES REACHING THE MID 80S. SCATTERED CONVECTION WILL CONTINUE INTO THE EVENING HOURS BEFORE DISSIPATING WITH LOSS OF HEATING. THE WARM CORE MID LEVEL LOW WILL BE EXITING THE REGION TO THE NORTHEAST TONIGHT...AND THEREFORE THE RAIN CHANCES WILL COME TO AN END. EXPECT A DRY SUNDAY WITH TEMPERATURES REBOUNDING INTO THE MID-UPPER 80S AREA WIDE. AS AN UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTER-MOUNTAIN WEST...A SURFACE LOW WILL DEEPEN IN THE HIGH PLAINS MONDAY. THIS WILL BRING BREEZY SOUTH WINDS TO THE REGION MONDAY WHICH WILL LIKELY PERSIST THROUGH THE WEEK. LOW TEMPS WILL WARM INTO THE 70S AREA WIDE BY MIDWEEK WITH HIGHS GENERALLY IN THE MID 80S EAST TO LOW 90S WEST. THE SOUTHWEST FLOW ABOVE THE SURFACE WILL BRING A THERMAL INVERSION INTO THE AREA. THUS THE FORECAST LOOKS DRY UNLESS/UNTIL FORCING ARRIVES TO WEAKEN THE CAP. MODEL GUIDANCE REMAINS IN POOR TO FAIR AGREEMENT REGARDING THE EVOLUTION/EJECTION OF THE WEST COAST UPPER TROUGH MID-LATE WEEK. THE ECMWF CONTINUES TO SHOW A VERY NEGATIVELY TILTED TROUGH SWINGING THROUGH THE REGION LATE WEDNESDAY AND THURSDAY WHICH WOULD BODE WELL FOR RAIN. BUT IT CONTINUES TO BE THE ONLY MODEL THAT SHOWS THE TROUGH EJECTION LIKE THIS...AND FRANKLY THE 500MB PATTERN IT PRESENTS JUST DOES NOT LOOK REALISTIC. IF IT WERE NOT FOR THE ECMWF BEING THE BETTER OF THE LONG RANGE MODELS...I WOULD DISCOUNT IT ALTOGETHER AND SHOW A DRY FORECAST ON THURSDAY...BUT FOR NOW HAVE RETAINED THE SLIGHT CHANCE POPS. THE GFS/UKMET/GEM FORECASTS SHOW THAT THE UPPER ENERGY NEEDED TO BREAK THE CAP WILL LIKELY REMAIN WELL NORTHWEST OF THE REGION. FURTHERMORE...THE DRYLINE ALSO LOOKS LIKE IT WILL REMAIN TOO FAR TO THE WEST...WITH THE GFS SHOWING IT AS FAR WEST AS THE TX PANHANDLE. STORM MOTIONS WILL GENERALLY BE NORTHEAST AND THIS MEANS STORMS WOULD NOT EVEN HAVE A CHANCE TO PROPAGATE INTO THE CWA EITHER. SO IN SUMMARY THE RAIN CHANCES ON THURSDAY AT THIS POINT ARE HINGING ON THE ECMWF BEING CORRECT...AND THIS MAY BE A BIT OF A LONG SHOT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 84 69 87 69 87 / 40 30 10 5 0 WACO, TX 83 68 87 68 89 / 50 30 10 5 0 PARIS, TX 83 67 85 66 85 / 30 30 10 5 0 DENTON, TX 84 67 86 68 87 / 40 30 10 5 0 MCKINNEY, TX 84 67 85 68 87 / 30 30 10 5 0 DALLAS, TX 85 71 87 70 89 / 40 30 10 5 0 TERRELL, TX 84 67 86 68 88 / 40 30 10 5 0 CORSICANA, TX 84 67 88 68 89 / 40 30 10 5 0 TEMPLE, TX 82 67 87 68 88 / 60 20 10 5 0 MINERAL WELLS, TX 81 66 87 67 89 / 40 20 10 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 82/69
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1213 PM CDT SAT MAY 25 2013 .UPDATE... THE PRIMARY FORECAST CHALLENGE FOR THE NEXT 24 HRS IS DETERMINING WHERE AND WHEN A MID-LEVEL LOW PRESSURE SYSTEM /MCV...CAUSED BY PERSISTENT THUNDERSTORM ACTIVITY THAT HAS DISSIPATED/ WILL MOVE OVER NORTH TX AND BRING US MORE THUNDERSTORM ACTIVITY. THE MID- LEVEL LOW FROM YESTERDAYS THUNDERSTORM ACTIVITY WAS DIFFICULT TO LOCATE THIS MORNING. 12Z UPPER AIR ANALYSIS INDICATED MID-LEVEL CYCLONIC CIRCULATIONS FROM NORTHWEST TX SOUTH TO THE HILL COUNTRY. IT IS POSSIBLE THAT THIS CYCLONIC SHEAR AXIS IS YESTERDAYS MID- LEVEL LOW...BUT SHEARED APART IN THE LARGER SCALE UPPER LEVEL RIDGE OVER THE REGION. JUST BEFORE NOON...THERE WAS A BAND OF RAIN SHOWERS AND EMBEDDED STORMS EXTENDING FROM STEPHENVILLE SOUTH TO THE AUSTIN AND SAN ANTONIO AREAS WHICH APPEARED TO BE ASSOCIATED WITH THIS SHEAR AXIS. THE MORE INTENSE THUNDERSTORMS AND RAIN SHOWERS WERE LOCATED AT THE FAR SOUTHERN END OF THIS LINE...CAUSING WIDESPREAD FLOODING AROUND THE CITY OF SAN ANTONIO AT THE TIME OF THIS DISCUSSION. DUE TO THE PERSISTENCE OF INTENSE RAIN SHOWER AND THUNDERSTORM ACTIVITY TO THE SOUTH OF THE CWA...WOULD EXPECT THAT A NEW OR REINFORCED MID-LEVEL LOW PRESSURE SYSTEM WOULD DEVELOP AROUND SAN ANTONIO SOMETIME TODAY. THERE HAS BEEN SOME INDICATION OF WEAK CYCLONIC CIRCULATIONS IN THE LIGHTER RAINFALL RETURNS TO THE NORTH OF SAN ANTONIO...IN BETWEEN TEMPLE AND AUSTIN. MID-LEVEL LOW PRESSURE SYSTEMS ARE CREATED BY THUNDERSTORMS DUE TO LARGE AMOUNTS OF LATENT HEAT RELEASED IN THE MIDDLE OF THE ATMOSPHERE DUE TO WATER VAPOR CONDENSING INTO WATER DROPLETS OR RAIN. BECAUSE THIS HAS BEEN GOING ON IN AN INTENSE FASHION NEAR SAN ANTONIO ALL MORNING...THINK THAT A MID-LEVEL LOW PRESSURE SYSTEM WILL LIKELY DEVELOP AROUND SAN ANTONIO /IF IT HAS NOT ALREADY/ AND BECOME THE DOMINANT MESOSCALE FEATURE DRIVING RAIN AND STORM CHANCES FOR NORTH TX OVER THE NEXT 24 HRS. THROUGH THIS AFTERNOON JUST ADJUSTED POPS TO HIGHLIGHT AREAS SOUTH OF INTERSTATE 20 AS HAVING THE HIGHEST RAIN CHANCES TODAY ASSUMING THE SAN ANTONIO LOW MOVES SLIGHTLY EAST THROUGH 7 PM. DID NOT REMOVE RAIN CHANCES TO THE NORTH BECAUSE THE WEAK CYCLONIC SHEAR AXIS STILL EXISTS AS FAR NORTH AS WICHITA FALLS...SO SOME RAIN AND THUNDERSTORM CHANCES ARE STILL WARRANTED NORTH OF INTERSTATE 20 THIS AFTERNOON. SEVERE WEATHER CHANCES REMAIN SMALL ACROSS ALL OF NORTH TX AS MID-LEVEL LAPSE RATES ARE POOR DUE TO YESTERDAYS THUNDERSTORM ACTIVITY AND DEEP LAYER SHEAR REMAINS WEAK AT THIS TIME. CAVANAUGH && .AVIATION... THE WEAK UPPER LOW OVER THE REGION WILL AGAIN RESULT IN AREAS OF SHRA/TSRA THROUGHOUT THE DAY. RADAR MOSAIC SHOWS THIS ACTIVITY CURRENTLY FROM THE KAUS/KSAT AREA NORTHWARD TO THE RED RIVER. AS THE DAY PROGRESSES EXPECT CONVECTION TO INCREASE IN COVERAGE WITH SOME AFFECTING THE TAF SITES MAINLY THIS AFTERNOON. AS THE UPPER LOW MOVES FARTHER NORTHEAST TONIGHT...SOME ACTIVITY WILL LINGER OVER THE AREA BUT IT SHOULD BE MOSTLY -RA AFTER 26/03Z. AIRPORT OPERATIONS WILL BE AFFECTED BY LIGHTNING STRIKES...WET RUNWAYS AND REDUCTIONS IN CIGS AND VIS DURING CONVECTION. KDFW OPERATIONS SHOULD EXPECT AN AIRPORT WEATHER WARNING TO BE ISSUED LATER TODAY AS LIGHTNING NEARS THE AIRPORT. FOR THIS TAF CYCLE...MVFR CIGS ARE ON GOING AT KACT BUT THEY SHOULD ARRIVE AT THE METROPLEX AIRPORTS 13-14Z. CIGS WILL LIFT TO VFR BY LATE MORNING. MVFR CIGS WILL RETURN TO KDFW LATE TONIGHT AROUND 26/09Z AND SHOULD END AROUND 26/16Z. 75 && .PREV DISCUSSION... /ISSUED 347 AM CDT SAT MAY 25 2013/ RADAR/SATELLITE LOOP INDICATES THAT THE WEAK MID LEVEL LOW IS LIKELY LOCATED NEAR ABILENE AND 00Z 500MB ANALYSIS CONFIRMS IT IS WARM-CORE IN NATURE. AS IS OFTEN THE CASE WITH WARM-CORE LOWS...CONVECTION IS FIRING BEFORE SUNRISE ACROSS THE HILL COUNTRY WITHIN A WEAK LOW LEVEL JET AXIS WHERE THETA-E ADVECTION AND OROGRAPHIC LIFT ARE OCCURRING. SHORT-TERM MODELS SUCH AS THE HRRR AND RUC SUGGEST THAT SCATTERED CONVECTION WILL CONTINUE TO EXPAND NORTHWARD FROM CENTRAL TEXAS INTO THE WESTERN ZONES DURING THE MORNING HOURS. THE GFS APPEARS TO BE SUFFERING FROM GRID SCALE CONVECTIVE FEEDBACK WHICH IS RESULTING IN VERY HIGH QPF AND CONTAMINATED MASS FIELDS...THUS THE GFS WILL NOT BE USED IN THE SHORT-TERM. THE NAM SEEMS TO BE MATCHING CURRENT TRENDS AND SHORT- TERM MODELS WELL AND THEREFORE IT GIVES CONFIDENCE TO RAISE POPS TODAY. WE EXPECT THE BEST COVERAGE OF CONVECTION IN THE WESTERN ZONES THIS MORNING. SCATTERED CONVECTION WILL BUILD/EXPAND EASTWARD INTO THE EASTERN ZONES DURING THE MIDDAY/AFTERNOON HOURS. THE AIRMASS OVER THE EASTERN ZONES WILL BE A BIT MORE UNSTABLE DUE TO BETTER INSOLATION AND A COUPLE OF STRONG STORMS WITH GUSTY WINDS WILL BE POSSIBLE...BUT DUE TO WEAK SHEAR THE SEVERE THREAT IS LOW. HIGHS TODAY IN THE WESTERN ZONES WILL ONLY BE IN THE UPPER 70S TO LOW 80S DUE TO CLOUDS/RAIN...WITH HIGHS IN THE EASTERN ZONES REACHING THE MID 80S. SCATTERED CONVECTION WILL CONTINUE INTO THE EVENING HOURS BEFORE DISSIPATING WITH LOSS OF HEATING. THE WARM CORE MID LEVEL LOW WILL BE EXITING THE REGION TO THE NORTHEAST TONIGHT...AND THEREFORE THE RAIN CHANCES WILL COME TO AN END. EXPECT A DRY SUNDAY WITH TEMPERATURES REBOUNDING INTO THE MID-UPPER 80S AREA WIDE. AS AN UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTER-MOUNTAIN WEST...A SURFACE LOW WILL DEEPEN IN THE HIGH PLAINS MONDAY. THIS WILL BRING BREEZY SOUTH WINDS TO THE REGION MONDAY WHICH WILL LIKELY PERSIST THROUGH THE WEEK. LOW TEMPS WILL WARM INTO THE 70S AREA WIDE BY MIDWEEK WITH HIGHS GENERALLY IN THE MID 80S EAST TO LOW 90S WEST. THE SOUTHWEST FLOW ABOVE THE SURFACE WILL BRING A THERMAL INVERSION INTO THE AREA. THUS THE FORECAST LOOKS DRY UNLESS/UNTIL FORCING ARRIVES TO WEAKEN THE CAP. MODEL GUIDANCE REMAINS IN POOR TO FAIR AGREEMENT REGARDING THE EVOLUTION/EJECTION OF THE WEST COAST UPPER TROUGH MID-LATE WEEK. THE ECMWF CONTINUES TO SHOW A VERY NEGATIVELY TILTED TROUGH SWINGING THROUGH THE REGION LATE WEDNESDAY AND THURSDAY WHICH WOULD BODE WELL FOR RAIN. BUT IT CONTINUES TO BE THE ONLY MODEL THAT SHOWS THE TROUGH EJECTION LIKE THIS...AND FRANKLY THE 500MB PATTERN IT PRESENTS JUST DOES NOT LOOK REALISTIC. IF IT WERE NOT FOR THE ECMWF BEING THE BETTER OF THE LONG RANGE MODELS...I WOULD DISCOUNT IT ALTOGETHER AND SHOW A DRY FORECAST ON THURSDAY...BUT FOR NOW HAVE RETAINED THE SLIGHT CHANCE POPS. THE GFS/UKMET/GEM FORECASTS SHOW THAT THE UPPER ENERGY NEEDED TO BREAK THE CAP WILL LIKELY REMAIN WELL NORTHWEST OF THE REGION. FURTHERMORE...THE DRYLINE ALSO LOOKS LIKE IT WILL REMAIN TOO FAR TO THE WEST...WITH THE GFS SHOWING IT AS FAR WEST AS THE TX PANHANDLE. STORM MOTIONS WILL GENERALLY BE NORTHEAST AND THIS MEANS STORMS WOULD NOT EVEN HAVE A CHANCE TO PROPAGATE INTO THE CWA EITHER. SO IN SUMMARY THE RAIN CHANCES ON THURSDAY AT THIS POINT ARE HINGING ON THE ECMWF BEING CORRECT...AND THIS MAY BE A BIT OF A LONG SHOT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 84 69 87 69 87 / 40 30 10 5 0 WACO, TX 83 68 87 68 89 / 50 30 10 5 0 PARIS, TX 83 67 85 66 85 / 30 30 10 5 0 DENTON, TX 84 67 86 68 87 / 40 30 10 5 0 MCKINNEY, TX 84 67 85 68 87 / 30 30 10 5 0 DALLAS, TX 85 71 87 70 89 / 40 30 10 5 0 TERRELL, TX 84 67 86 68 88 / 40 30 10 5 0 CORSICANA, TX 84 67 88 68 89 / 40 30 10 5 0 TEMPLE, TX 82 67 87 68 88 / 60 20 10 5 0 MINERAL WELLS, TX 81 66 87 67 89 / 40 20 10 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1038 AM PDT Sat May 25 2013 .SYNOPSIS... Memorial Day Weekend is expected to be a little cooler than average, and a series of weak upper level disturbances will bring the potential for scattered showers Sunday and Monday. The moist, showery weather pattern is expected to linger into late next week. && .DISCUSSION... Update: Satellite imagery from this morning shows two closed lows...one near the north Washington coast and another over southern Alberta. Models show these two features moving very little today. With no strong forcing mechanism to generate showers...there should be less shower activity today compared to yesterday. The 13z HRRR model shows most of the showers today will be along the East Slopes of the Cascades and north of the Columbia Basin over the northern mountains. This make sense given these areas are in closest proximity to the two aforementioned lows...and that showers are more likely to develop over the mountainous terrain. Forecast has this part of the forecast well handled with only change to lower mountain pops to 20 percent through the morning with better chances holding off til afternoon when instability increases. Latest SREF and SPC guidance, as well as the 13z HRRR model shows minimal thunder chances today. The better chances will be north of the Canadian border...and over the Clearwaters. With cloud cover this morning extensive over the Idaho Panhandle and northeast Washington mountains...this will further lower convective potential. Cloud cover was increased this morning over North Idaho, and thunder was removed from the northern mountains, but a slight chance was kept for the Camas Prairie with this area on the edge of the best convective potential. Also lowered high temperatures today a few degrees for Sandpoint and Kellogg. JW && .AVIATION... 18Z TAFS: An upper level trough will remain over the Inland Northwest over the next 24 hours. Today showers will increase mainly over the mountains but instability is marginal for thunderstorms with none expected. These showers will die off after 03z with the loss of daytime heating. Another disturbance embedded within this trough will spreading thickening cloud cover into the region between after 14z Sunday especially KEAT/KMWH where a few showers may develop. The bulk of the showers should hold off til after 18z Sunday. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 63 44 65 46 65 47 / 20 10 30 40 30 10 Coeur d`Alene 63 42 65 45 64 44 / 20 20 30 40 40 10 Pullman 64 43 63 44 65 46 / 10 10 30 40 20 20 Lewiston 71 48 70 50 71 51 / 10 10 30 40 20 20 Colville 67 41 72 45 69 44 / 40 30 20 20 50 20 Sandpoint 61 39 66 43 63 42 / 30 20 20 40 50 20 Kellogg 59 44 63 46 62 47 / 40 20 30 50 50 20 Moses Lake 72 46 73 49 73 50 / 10 10 30 20 10 20 Wenatchee 68 47 70 49 71 51 / 10 10 30 10 10 20 Omak 68 41 71 45 70 46 / 30 20 30 10 20 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 PM CDT SAT MAY 25 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 341 PM CDT SAT MAY 25 2013 AT 3 PM...A DYING MESOSCALE CONVECTIVE COMPLEX WAS LOCATED OVER CENTRAL ILLINOIS. THIS SYSTEM PRODUCED UP TO 4 INCHES OF RAIN ACROSS PARTS OF STORY...MARSHALL...AND JASPER COUNTIES IN CENTRAL IOWA. MEANWHILE NORTHEAST IOWA AND MOWER COUNTY IN SOUTHEAST MINNESOTA...RECEIVED UP TO A THIRD OF AN INCH /KARX RADAR WAS OVERESTIMATING BY UP TO 300 PERCENT IN SOME LOCATIONS/. THE RAIN AND CLOUDS FROM THIS SYSTEM KEPT TEMPERATURES IN THE LOWER AND MID 50S IN THESE AREAS WHICH IS VERY CLOSE TO THE RECORD COLDEST MAXIMUM TEMPERATURES FOR THE DATE. THE RECORD COLD MAXIMUM FOR THE DATE IS 46 IN 1992 FOR AUSTIN MN...48 IN 1943 IN CHARLES CITY IA...AND 53 IN 1992 IN DECORAH IA. THE DECORAH RECORD IS THE ONLY ONE THAT COULD POSSIBLY BE BROKEN OR TIED. MEANWHILE AREAS NORTH OF INTERSTATE 94 SAW A BIT OF SUNSHINE AND THEY WERE ABLE TO WARM INTO THE MID 60S. FOR TONIGHT AND SUNDAY...THE MAIN CONCERN IS THE TRACK OF THE MESOSCALE CONVECTIVE COMPLEX OVER WESTERN NORTH DAKOTA. CORFIDI VECTORS SUGGEST THAT THIS SYSTEM WILL MOVE EAST ACROSS THE DAKOTAS THIS EVENING...AND THEN IT WILL MOVE SOUTHEAST ACROSS THE EASTERN THIRD OF SOUTH DAKOTA...SOUTHERN AND WESTERN MINNESOTA AND NORTHERN IOWA TONIGHT. OVERALL...THE 25.18Z HRRR HAS THE BEST HANDLE ON THIS SYSTEM AND IT HAS THIS SYSTEM OVER SOUTHWEST MINNESOTA BY 26.06Z. WITH THAT SPEED...IT SHOULD MOVE INTO NORTHEAST IOWA AND PARTS OF SOUTHEAST MINNESOTA BY 26.10Z...AND THEN LINGER ACROSS THESE AREAS THROUGH MUCH OF SUNDAY MORNING. AHEAD OF THIS SYSTEM...THE RAP...GFS...NAM/WRF...AND ECMWF SHOW THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP NORTH OF A WARM FRONT FROM NORTHWEST IOWA TO SOUTHEAST IOWA. THIS PRECIPITATION IS ASSOCIATED WITH MODERATE 925 TO 850 MB MOISTURE TRANSPORT AND 310K ISENTROPIC LIFT. LIKE TODAY...EXPECT THE LOW CLOUDS AND PRECIPITATION TO KEEP TEMPERATURES IN THE MID AND UPPER 50S ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN ON SUNDAY. MEANWHILE SOME SUN NORTH OF INTERSTATE 94 WILL ALLOW TEMPERATURES TO WARM INTO THE MID 60S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 341 PM CDT SAT MAY 25 2013 ON SUNDAY NIGHT AND MONDAY...THE WARM FRONT WILL MOVE INTO NORTH SOUTHWEST IOWA. WEAK TO MODERATE 925 AND 850 MB MOISTURE TRANSPORT WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS NORTH OF THE WARM FRONT FROM NORTH CENTRAL IOWA SOUTHEAST INTO SOUTHEAST IOWA. THE GFS...ECMWF...AND GEM SUGGEST THAT A MESOSCALE CONVECTIVE COMPLEX WILL DEVELOP ACROSS EASTERN SOUTH DAKOTA LATE SUNDAY NIGHT...AND THE DYING SYSTEM MOVES EAST THROUGH OUR AREA MONDAY. FROM MONDAY NIGHT INTO TUESDAY...THE MODELS ARE CONTINUING TO STRUGGLE WITH THE LOCATION OF THE WARM FRONT. THE NAM/WRF STALLS THE WARM FRONT NEAR THE MINNESOTA AND IOWA BORDER. THIS MAKES A LOT OF SENSE IF A LOT OF CONVECTION DEVELOPS NORTH OF THIS FRONT AND ITS COLD POOL PREVENTS THIS WARM FRONT MOVING ANY FURTHER NORTH. MEANWHILE THE GFS AND ECMWF WOULD SYNOPTICALLY FAVOR THAT THE WARM FRONT WOULD MOVE NORTHWARD THROUGH THE AREA. HOWEVER THE CAP IN THE WARM SECTOR REMAINS SOUTHWEST OF THE FORECAST AREA...THUS THERE WOULD BE THE POTENTIAL FOR A SERIES OF MESOSCALE CONVECTIVE SYSTEMS TO MOVE THROUGH THE AREA. SO IN EITHER SCENARIO...IT LOOKS LIKE THE FORECAST AREA WILL REMAIN WET. WITH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES AND WARM CLOUD LAYER DEPTHS UP TO 4KM...THERE WILL BE THE POTENTIAL FOR HEAVY RAIN FROM ANY SHOWERS AND THUNDERSTORMS THAT DEVELOP. IN ADDITION...WILL HAVE TO WATCH FOR THE POTENTIAL OF SEVERE WEATHER...BUT THIS IS HIGHLY DEPENDENT UPON THE LOCATION OF THE WARM FRONT. FROM TUESDAY NIGHT INTO SATURDAY...IT CONTINUES TO LOOK LIKE A SERIES OF SHORT WAVE TROUGHS WILL MOVE THROUGH THE REGION. HOWEVER THE TIMING OF THESE WAVES IS UNCERTAIN...THUS KEPT PRECIPITATION CHANCES IN THE 40 TO 60 PERCENT RANGE THROUGH THIS TIME PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1208 PM CDT SAT MAY 25 2013 AREA OF MVFR CEILINGS OVER SOUTHERN INTO WESTERN MINNESOTA HAS SLIPPED INTO KRST. THE 25.15Z RAP INDICATES THESE SHOULD REMAIN THROUGH ABOUT THE MIDDLE OF THE AFTERNOON BEFORE THEY RISE TO A LOW VFR LEVEL FROM THE HEATING OF THE DAY. THE CONCERN FOR THE OVERNIGHT HOURS IS WHETHER THE NEXT CONVECTIVE COMPLEX WILL IMPACT THE TAF SITES. THE 25.12Z NAM ALONG WITH THE 25.06Z HI-RES ARW BOTH SUGGEST THE WARM FRONT WILL REMAIN SOUTH OF THE AREA. THE NEXT COMPLEX IS EXPECTED TO DEVELOP OVER SOUTH DAKOTA AND THEN RIDE SOUTHEAST ALONG THE FRONT MOVING ACROSS IOWA INTO ILLINOIS STAYING SOUTH OF BOTH AIRPORTS. AT THIS POINT...WILL NOT EVEN INCLUDE A VCSH BUT WILL LOWER THE CEILINGS EXPECTING THE NORTHERN EDGE OF THE LOWER CLOUDS FROM THE CONVECTIVE COMPLEX TO IMPACT BOTH AIRPORTS. THE NAM BUFKIT SOUNDINGS SHOWS KRST GOING DOWN TO MVFR WITH KLSE STAYING VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1209 PM CDT SAT MAY 25 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 230 AM CDT SAT MAY 25 2013 LOW/MID LEVEL FRONTOGENETIC FORCING...COUPLED WITH SOME LOW LEVEL MOISTURE TRANSPORT AND A BIT OF UPPER LEVEL ENERGY...WERE HELPING CONTINUE AN AREA OF EAST/SOUTHEAST MOVING SHOWERS. TRENDS IN THE LATEST HRRR/NAM12 IS TO DIMINISH THIS ACTIVITY THROUGH THE PRE DAWN HOURS...WHILE FIRING CONVECTION OVER THE SOUTHERN PLAINS/WESTERN IA. SATELLITE IMAGERY AND RADAR RETURNS ALREADY SHOW THIS HAPPENING...WHERE THE NOSE OF THE LOW LEVEL JET/MOISTURE TRANSPORT WAS LOCATED. THIS COMPLEX SHOULD MOVE EAST THROUGH THE REST OF THE MORNING INTO THE AFTERNOON...RIDING ALONG AND NORTH OF A WARM FRONT. THIS REGION SHOULD SERVE AS THE FOCUS FOR MORE SHOWER/STORM DEVELOPMENT TONIGHT...WITH THE LOW LEVEL JET REASSERTING ITSELF AND SOME UPPER LEVEL ENERGY MOVING OUT OF A WEST COAST TROUGH. EASTWARD MOVEMENT WOULD AGAIN BE FAVORED...KEEPING THE BULK OF THE PCPN SOUTH OF THE FORECAST AREA. .LONG TERM...(SUNDAY THROUGH SATURDAY) ISSUED AT 230 AM CDT SAT MAY 25 2013 HIGH CONFIDENCE ITS GOING TO RAIN ACROSS PARTS OF THE REGION THROUGH THE UPCOMING WORK WEEK. TIMING AND PLACEMENT IS MORE SHAKY. THE FORECAST KEYS ON A FEW AREAS...A SFC WARM FRONT...LOW LEVEL JET/MOISTURE TRANSPORT...AND VARIOUS MCVS. WHERE THESE ELEMENTS ALL COME TOGETHER WILL BE WHERE THE GREATER THREAT FOR RAIN WILL LIE. CLARITY FOR THE MESOSCALE VORTICIES/SPAWNING GROUNDS AND MOVEMENT IS THE MAIN STICKING POINT FOR INCREASING CONFIDENCE. THE UPPER LEVEL PATTERN IS SLOW TO PROGRESS EAST AS THERE IS LITTLE IMPETUS VIA 250/300MB JET INTERACTION - RELATIVELY QUIET A LOFT. SO...THE 500 MB RIDGE WILL REMAIN ACROSS THE UPPER MISSISSIPPI RIVER VALLEY/GREAT LAKES INTO AT LEAST THE MIDDLE PART OF THE NEW WORK WEEK...WITH A BROAD TROUGH OVER THE WEST COAST. BITS OF ENERGY WILL SPIN OUT OF THE TROUGH...AND THEN ENHANCE VIA CONVECTION SPAWNED BY IT AND THE LOW LEVEL JET/MOISTURE TRANSPORT. WITH THE RIDGE OVERHEAD THE NEXT FEW DAYS...AND THE SFC WARM FRONT HOLDING TO THE SOUTH...THESE UPPER AIR INFLECTIONS ARE PROGGED TO RIDE ALONG AND NORTH OF THE WARM FRONT...KEEPING THE BEST RAIN CHANCES JUST SOUTH -BUT NOT COMPLETELY OUT- OF THE FORECAST AREA. THE WARM FRONT WILL START TO LIFT NORTH ON TUE...A FAIRLY CONSISTENT SIGNAL IN THE NAM/GFS/ECMWF. HOW FAR NORTH IS NOT THOUGH...WITH THE GFS APPEARING THE MORE AGGRESSIVE IN HOW FAR NORTH AND HOW FAST. RAIN CHANCES LOOK TO BECOME MORE WIDESPREAD FOR THE FORECAST AREA MON-TUE AS A RESULT. DEPENDING ON HOW QUICKLY AND HOW FAR NORTH THE WARM FRONT MAKES IT...THE AREA COULD GET INTO THE WARM SECTOR...WHICH WOULD HELP CAP OFF THE ATMOSPHERE TO CONVECTION - OUTSIDE OF A KICKER MOVING IN. MODEL DIFFERENCES START TO BECOME BIGGER AS WE MOVE TOWARD NEXT WEEKEND...WITH THE EC SUGGESTING A CLOSED LOW WILL DEVELOP IN THE WEST COAST TROUGH...SLOWLY PUSHING EAST ACROSS THE UPPER MISSISSIPPI RIVER VALLEY NEXT WEEKEND. THIS COULD LAY UP A SFC TROUGH ACROSS THE REGION FOR SEVERAL DAYS. THE GFS IS MORE PROGRESSIVE...MOVING THE UPPER LEVEL ENERGY NORTHEAST...BUT STILL HAS A COUPLE SFC BOUNDARIES THAT COULD ACT AS SHOWER/STORM PRODUCERS. WILL LIKELY STAY WITH THE CONSENSUS SOLUTION FOR THE DETAILS IN THIS PART OF THE FORECAST. AS FOR STORM CHANCES...INSTABILITY IS LIMITED THE NEXT COUPLE DAYS...AND SO SHOULD BE THE THUNDERSTORMS. THE CHANCE FOR BOOMERS WILL INCREASE WITH THE ENCROACHMENT OF THE WARM FRONT...AND SUBSEQUENT INCREASE IN CAPES. DON/T SEE A SIGNIFICANT THREAT FOR ORGANIZED SEVERE WEATHER THROUGH NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1208 PM CDT SAT MAY 25 2013 AREA OF MVFR CEILINGS OVER SOUTHERN INTO WESTERN MINNESOTA HAS SLIPPED INTO KRST. THE 25.15Z RAP INDICATES THESE SHOULD REMAIN THROUGH ABOUT THE MIDDLE OF THE AFTERNOON BEFORE THEY RISE TO A LOW VFR LEVEL FROM THE HEATING OF THE DAY. THE CONCERN FOR THE OVERNIGHT HOURS IS WHETHER THE NEXT CONVECTIVE COMPLEX WILL IMPACT THE TAF SITES. THE 25.12Z NAM ALONG WITH THE 25.06Z HI-RES ARW BOTH SUGGEST THE WARM FRONT WILL REMAIN SOUTH OF THE AREA. THE NEXT COMPLEX IS EXPECTED TO DEVELOP OVER SOUTH DAKOTA AND THEN RIDE SOUTHEAST ALONG THE FRONT MOVING ACROSS IOWA INTO ILLINOIS STAYING SOUTH OF BOTH AIRPORTS. AT THIS POINT...WILL NOT EVEN INCLUDE A VCSH BUT WILL LOWER THE CEILINGS EXPECTING THE NORTHERN EDGE OF THE LOWER CLOUDS FROM THE CONVECTIVE COMPLEX TO IMPACT BOTH AIRPORTS. THE NAM BUFKIT SOUNDINGS SHOWS KRST GOING DOWN TO MVFR WITH KLSE STAYING VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04