Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/12/14


AREA FORECAST DISCUSSION
NWS NEW YORK NY
702 PM EDT SAT MAY 10 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS LATE TONIGHT. HIGH PRESSURE THEN BUILDS OVER THE AREA ON SUNDAY AND SUNDAY NIGHT. HIGH PRESSURE DEPARTS ON MONDAY...AND THEN A SERIES OF FRONTAL BOUNDARIES AND WEAK LOW PRESSURE SYSTEMS WILL MOVE ACROSS THE REGION THROUGH THE MIDDLE OF THE WEEK. A STRONGER COLD FRONT IMPACTS THE REGION LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... SOME BREAK IN CONVECTIVE ACTIVITY WILL BE SEEN ACROSS MUCH OF THE REGION OUTSIDE OF INTERIOR SOUTHERN CT BEFORE 10 PM. SOME SCATTERED CONVECTION WILL STILL BE IN THE FORECAST THIS EVENING. THE CHANCE INCREASES LATER THIS EVENING WHEN ANOTHER AREA OF SHOWERS WILL BE APPROACHING FROM SOUTH CENTRAL PA. THIS IS MODELED BY THE HRRR TO MOVE THROUGH BETWEEN 03-07Z. INSTABILITY WILL BE LOWERING GOING THROUGH THE EVENING...ALLOWING THUNDERSTORMS TO BECOME LESS IN COVERAGE. OTHERWISE...JUST SOME MINOR ADJUSTMENTS MADE TO TEMPS AND DEWPOINTS WITH NO OTHER REMARKABLE CHANGES MADE. THROUGH EARLY THIS EVENING...MAIN THREAT WITH ANY THUNDERSTORMS WILL BE BRIEF GUSTY WINDS AND HEAVY DOWNPOURS. FOR THE NEXT FEW ROUNDS OF CONVECTION BACK IN PA THROUGH CENTRAL NY...THEY WILL BE ARRIVING INTO A COOLER BUT STILL MOIST AIRMASS LATER THIS EVENING. EXPECTING THE THUNDERSTORMS TO BE LESS COVERAGE GOING TO MID TO LATE EVENING AS TEMPERATURES COOL AND FORCING JUST REMAINS AHEAD OF THE SHORTWAVE AND COLD FRONT AT THE SURFACE. THE JET STREAM ALOFT WILL MOVE NEAR THE REGION THIS EVENING AND SHOULD KEEP DIVERGENCE GOING ALOFT...ALLOWING FOR A HIGHER CHANCE OF PRECIP. ALSO...WITH RATHER LIGHT WESTERLY FLOW BEHIND THE FRONT...THINKING LOW LEVELS WILL BE SLOWER TO DRY OUT LATE TONIGHT. THEREFORE...HAVE PATCHY FOG DEVELOPING LATE. LOWS WERE A BLEND OF NAM12 AND MET GUIDANCE...HIGHER SIDE OF GUIDANCE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... BEHIND THE COLD FRONT...MID LEVEL RIDGING WITH HIGH PRESSURE BUILDING IN AT THE SURFACE FROM THE SOUTH AND WEST WILL PROMOTE DRY WEATHER DURING THIS PERIOD. WITH THE WESTERLY FLOW SUNDAY...EXPECTING A QUICK INCREASE TO TEMPERATURES IN THE MORNING WITH HIGHS WELL ABOVE NORMAL ONCE AGAIN...IN THE MID 70S TO LOWER 80S RANGE FOR MOST PLACES. THE JET STREAM ALOFT WILL BE LIFTING FARTHER NORTH OF THE REGION WITH THE RIDGING. HIGHS WERE TAKEN FROM MAVS AND INCREASED TWO DEGREES. SKIES WILL BE CLEARING SUNDAY AND THESE MOSTLY CLEAR SKIES LINGER INTO SUNDAY NIGHT. LOWS SUNDAY NIGHT WILL BE COOLER THAN OF RECENT NIGHTS WITH RADIATIONAL COOLING AS WINDS WILL BE LIGHT. LOWS SUNDAY NIGHT WERE TAKEN FROM ECS AND CONVEY A RANGE FROM THE MID 40S ACROSS RURAL AND INTERIOR LOCATIONS TO THE LOWER 60S NEAR NYC. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGH PRES DEPARTS ON MONDAY AS A DEEP UPPER TROUGH DIGS INTO THE CENTRAL U.S. THIS TROUGH WILL EXTEND FROM CANADA INTO THE GULF OF MEXICO...AND SFC LOW PRES WILL DEVELOP OVER THE WESTERN GREAT LAKES BEFORE TRACKING TO THE NORTHEAST INTO CANADA. MEANWHILE...A WARM FRONT APPROACHES ON MONDAY...AND THEN WEAK LOW PRES FORMS ALONG THE BOUNDARY AS IT LIFTS TO THE NORTH. THAT BOUNDARY WILL BECOME NEARLY STATIONARY NORTH OF THE REGION ON TUESDAY. AS A RESULT...WILL EXPECT SCATTERED SHOWERS AND TSTMS TO DEVELOP MONDAY AFTERNOON...MAINLY ACROSS NORTHERN ZONES. UNSETTLED WEATHER CONTINUES INTO TUESDAY AS HIGH PRES OVER EASTERN CANADA DROPS SOUTH INTO THE GOLF OF MAINE. THE STATIONARY FRONT NORTH OF THE AREA WILL PUSH TO THE SOUTH AS A BACK DOOR COLD FRONT...AND THEN THE HIGH ANCHORS ITSELF OVER THE WESTERN ATLANTIC THROUGH THE END OF THE WEEK. THE UPPER TROUGH OVER THE MIDWEST WILL SLOWLY TRACK EAST...BUT WILL EFFECTIVELY BECOME BLOCKED BY THE OFFSHORE HIGH. SEVERAL WEAK IMPULSES WILL DEVELOP AT THE BASE OF THE TROUGH...AND THOSE WILL TRACK TOWARDS THE REGION...KEEPING UNSETTLED WEATHER IN THE FORECAST THROUGH THE END OF THE WEEK. THE HIGH MOVES TO THE EAST THURSDAY NIGHT...AND THEN THE UPPER TROUGH MOVES INTO THE EASTERN U.S. THERE ARE SOME INDICATIONS THAT THE TROUGH BECOMES NEGATIVELY TILTED...AND THEN LOW PRES WILL DEVELOP OVER THE MID-ATLANTIC BEFORE MOVING THROUGH THE REGION THURSDAY NIGHT THROUGH FRIDAY. WILL BUMP UP POPS TO LIKELY FOR MOST OF THE REGION FOR THAT TIME FRAME. COULD BE SOME LINGERING SHOWERS INTO SATURDAY AS SEVERAL STRONG SHORTWAVES DIVE INTO THE REGION AS THE TROUGH MOVES OVERHEAD. SUMMER-LIKE TEMPS CONTINUE ON MONDAY WITH HIGHS WELL ABOVE NORMAL...TOPPING OFF IN THE LOW 80S WEST OF THE HUDSON RIVER AND IN THE MID TO UPPER 70S MOST ELSEWHERE...AND COOLER NEAR THE COASTS. TEMPS RETURN CLOSER TO NORMAL ON TUESDAY...TOPPING OFF IN THE UPPER 60S TO LOWER 70S WITH THE WARMEST TEMPS ONCE AGAIN WEST OF THE HUDSON RIVER. BY WEDNESDAY...BEHIND THE BACK DOOR COLD FRONT AND WITH ONSHORE FLOW...HIGHS WILL RANGE FROM THE UPPER 50S NEAR THE COASTS TO THE MID 60S ACROSS THE INTERIOR. TEMPS WILL THEN TOP OFF AROUND NORMAL TO CLOSE OUT THE WEEK...GENERALLY IN THE UPPER 60S. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS THIS AFTN INTO THE EVENING. A COLD FRONT APPROACHES AND PASSES TONIGHT...BRINGING PERIODS OF SUB-VFR CONDITIONS. SW FLOW THIS AFTN/EVENING...GENERALLY 8-13 KTS. OCNL GUSTS PSBL 18-25 KTS. GUSTS WILL SUBSIDE AFTR 00Z. VIS MAINLY P6SM...THOUGH ANY PCPN COULD DROP VIS TO 3-5SM FOR A PERIOD. CIGS MAINLY VFR...WITH INCREASING MID AND HIGH LEVEL CLOUDS. CIGS COULD DROP TO 1500-2500 FT WITH ANY PCPN. PSBL STRATUS OVER EASTERN AREAS AS WELL THIS EVENING AHEAD OF FRONTAL PASSAGE. FIRST ROUND OF PCPN PSBL AFTR 19Z...WITH HIGHER CONFIDENCE OF THE 21-01Z TIME FRAME. MAINLY SHRA BUT COULD SEE ISO TSTM...LOW CONFIDENCE OF COVERAGE/TIMING AT THIS TIME AND WILL NOT INCLUDE. ANOTHER ROUND OF PCPN THIS EVENING/EARLY OVERNIGHT RIGHT AHEAD OF FRONT...MAINLY SHRA. WILL BRING SUB-VFR CONDITIONS FOR BOTH VIS/CIGS. WINDS SHIFT BEHIND FRONT AFTR 06Z TO WNW FLOW. .OUTLOOK FOR 18Z SUN THROUGH THURSDAY... .SUN-MON...VFR WITH W/NW FLOW. .MON NIGHT-THURS...PERIODS OF MVFR OR LOWER WITH PCPN. && .MARINE... PATCHY FOG CAN BE EXPECTED ACROSS THE WATERS TONIGHT WITH MOIST LOW LEVELS. SCA CONDITIONS STILL EXPECTED FOR THE OCEAN BUT SYNOPTIC GUSTS WILL BE MARGINAL...NEAR 25 KT BUT FREQUENCY MAY BE MORE OCCASIONAL WITH THIS. HOWEVER...EXPECTING THE INCREASING SW FETCH WILL HELP BUILD SEAS AS WELL TO 5 FT ACROSS THE OCEAN ZONES. JUST EASTERN OCEAN ZONES HAVE SCA CONDITIONS THROUGH TONIGHT WITH WESTERN OCEAN UNTIL MIDNIGHT. FOR SUNDAY AND SUNDAY NIGHT...SUB SCA CONDITIONS ARE EXPECTED WITH HIGH PRESSURE IN CONTROL. SUB-SCA CONDITIONS ON TAP FOR THE START THE NEW WEEK. BY THE MIDDLE OF NEXT WEEK...SMALL CRAFT CONDITIONS RETURN AS A PERSISTENT ONSHORE FLOW WILL HELP PUSH OCEAN SEAS UP TO 3-5 FT. && .HYDROLOGY... AROUND THREE TENTHS TO A HALF INCH OF BASIN AVERAGE QPF IS EXPECTED THROUGH TONIGHT WITH SOME HIGHER AMOUNTS FROM CONVECTION. ANY FLOODING POTENTIAL IS EXPECTED TO BE GENERALLY MINOR...PARTICULARLY FOR THOSE LOCATIONS GETTING MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS. SCATTERED SHOWERS/TSTMS COULD PRODUCE LOCALLY HEAVY RAIN FOR MOST OF THE UPCOMING WEEK...BUT WIDESPREAD ORGANIZED PRECIPITATION OF 1/2" QPF OR MORE WILL HOLD OFF UNTIL LATE NEXT WEEK WHEN LOW PRESSURE TRACKS THROUGH THE REGION. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ355. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ350-353. && $$ SYNOPSIS...JM/MPS NEAR TERM...JM SHORT TERM...JM LONG TERM...MPS AVIATION...SEARS MARINE...JM/MPS HYDROLOGY...JM/MPS
AREA FORECAST DISCUSSION
NWS ALBANY NY
423 AM EDT SAT MAY 10 2014 .SYNOPSIS... A WARM FRONT WILL CONTINUE TO LIFT ACROSS THE REGION DURING THE MORNING HOURS WITH SOME SHOWERS AND ISOLATED THUNDERSTORMS. LATER DURING THE DAY TODAY...A WEAK COLD FRONT WILL CROSS THE REGION...BRINGING SOME ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE AREA FOR THIS AFTERNOON INTO THIS EVENING. HIGH PRESSURE WILL BUILD IN FOR TOMORROW WITH FAIR AND MILD WEATHER. A FRONTAL BOUNDARY APPROACHING FROM THE NORTH WILL RETURN THE THREAT FOR SOME RAIN SHOWERS ON MONDAY...WITH CONTINUED WARM TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 423 AM EDT...AN UPPER LEVEL SHORTWAVE TROUGH IS SITUATED OVER THE GREAT LAKES. AHEAD OF THIS SYSTEM...A MOIST SW FLOW RIGHT OUT OF THE GULF OF MEXICO IS TRANSPORTING PLENTY OF AMPLE MOISTURE TOWARDS UPSTATE NY AND NEW ENGLAND. PWAT VALUES WERE AROUND 1.00 INCH ON THE 00Z KALY SOUNDING...AND MODELS PROJECTIONS SHOW THIS RISING TO NEARLY 1.50 INCHES AT ALBANY TOWARDS SUNRISE...WHICH WOULD BE NEARING ABOUT 2 STD ABOVE NORMAL. AT THE SURFACE...A NORTH TO SOUTH ORIENTED WARM FRONT OVER CENTRAL NEW YORK IS FINALLY MAKING ITS WAY ACROSS OUR REGION FROM WEST TO EAST. THIS WARM FRONT HAS BEEN HUNG UP JUST SOUTH AND WEST OF OUR AREA FOR NEARLY TWO DAYS...AND IS FINALLY GETTING THE PUSH IT NEEDS TO OVERCOME THE STABLE MARINE LAYER THAT HAS BEEN IN PLACE ACROSS OUR AREA. A WIDESPREAD AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS ARE CURRENTLY MOVING ACROSS THE NORTHERN PART OF THE AREA...AND THIS LOOKS TO CONTINUE FOR THE NEXT FEW HOURS AS THE WARM FRONT MOVES ACROSS THE REGION THIS MORNING. WHILE SOME SHOWERS OR ISOLATED THUNDERSTORMS ARE POSSIBLE EVERYWHERE...RADAR TRENDS AND HIRES MODEL OUTPUT FROM THE 3KM HRRR AND LOCAL WRF ALL SUGGEST THAT NORTHERN HALF OF THE AREA WILL HAVE THE MOST CONCENTRATED ACTIVITY. ANY THUNDER LOOKS RATHER ISOLATED DUE TO THE STABLE LOW LEVELS...BUT WITH SHOWALTER VALUES CLOSE TO ZERO...THERE MAY BE JUST ENOUGH ELEVATED INSTABILITY FOR A FEW RUMBLES OF THUNDER HERE AND THERE. THE WARM FRONT SHOULD BE THROUGH BY THE MID TO LATE MORNING...AND THERE SHOULD BE BREAK IN THE ACTIVITY. THE COLD FRONT WILL REMAIN UPSTREAM OVER THE EASTERN GREAT LAKES...AND WITH OUR REGION IN THE WARM SECTOR...WE WILL HAVE A MILD DAY. ALTHOUGH THERE WILL BE PLENTY OF LOW STRATUS TO START THE DAY...SOME BREAKS OF SUNSHINE SHOULD OCCUR BY THE LATE MORNING OR EARLY AFTERNOON...AND DECENT MIXING WILL OCCUR...AS A S-SW BREEZE AT LOW LEVELS WILL BE IN PLACE. MAX TEMPS LOOK TO REACH WELL INTO THE 70S FOR VALLEY LOCATIONS...WITH UPPER 60S OVER THE HIGH TERRAIN. WITH THE COLD FRONT PASSING THROUGH LATE IN THE DAY...THERE LOOKS TO BE SOME ADDITIONAL SCATTED SHOWERS AND THUNDERSTORMS...MAINLY FOR AREAS FROM THE CAPITAL REGION ON SOUTH. WITH THE BREAKS OF SUN...THERE MAY BE BETTER INSTABILITY THAN EARLIER IN THE DAY TO ALLOW FOR A LITTLE MORE THUNDER. STILL...NO SEVERE WX IS ANTICIPATED...AS INSTABILITY WILL BE MEAGER...AND LOW DEWPOINTS/WEAK FORCING WILL PREVENT ANY STORM FROM BECOMING TOO STRONG. THE THREAT FOR SHOWERS/TSTMS WILL END FROM NORTH TO SOUTH DURING THE EVENING AS THE COLD FRONT PASSES THROUGH THE AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... ANY LINGERING SHOWERS DOWN SOUTH WILL END SHORTLY AFTER SUNSET THIS EVENING AS THE COLD FRONT STARTS TO SHIFT SOUTH AND EAST OF THE REGION...AND HIGH PRESSURE BEGINS TO BUILD IN FROM THE GREAT LAKES. CLOUDS WILL CLEAR OUT AND A COOLER AND LESS HUMID NIGHT IS EXPECTED TONIGHT...WITH LOWS IN THE 40S TO LOW 50S. DRY AND PLEASANT WEATHER IS EXPECTED ON SUNDAY WITH LOW HUMIDITY AND DEEP MIXING. WESTERLY WINDS WILL BE BREEZY WITH PLENTY OF SUNSHINE...AND MAX TEMPS LOOK TO REACH INTO THE 70S FOR MANY AREAS. WITH HIGH PRESSURE NEARBY...DRY WEATHER WILL CONTINUE AND MIN TEMPS WILL BE COOL FOR SUNDAY NIGHT...WITH UPPER 30S TO UPPER 40S ACROSS THE REGION. ANOTHER FRONTAL BOUNDARY LOOKS TO DROP ACROSS THE REGION FOR MONDAY. THIS BOUNDARY WILL BE RATHER WEAK...BUT WITH DAYTIME HEATING...SOME SHOWERS WILL BE POSSIBLE BY THE AFTN HOURS. TEMPERATURES WILL VARY ACROSS THE REGION THANKS TO THE BOUNDARY...AS NORTHERN AREAS MAY ONLY REACH THE UPPER 60S TO LOW 70S...WHILE SOUTH OF THE BOUNDARY ACROSS THE MID HUDSON VALLEY...MAX TEMPS MAY REACH IN THE LOW 80S. THE BEST CHC OF SEEING A SHOWER WILL BE ACROSS THE ADIRONDACKS. WE WONT INCLUDE THUNDER JUST YET...AS INSTABILITY AND DEEP MOISTURE DOESN/T LOOK TOO HIGH JUST YET...LIMITING THE THUNDER THREAT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MOST OF THE UPCOMING WEEK WILL BE UNSETTLED AS UPPER PATTEN BECOMES INCREASINGLY AMPLIFIED ACROSS NOAM. MONDAY NIGHT... CENTRAL CONUS WILL BECOME UNDER THE INFLUENCE OF AN AMPLIFYING UPPER TROUGH. MEANWHILE...RIDGE WILL AMPLIFY ACROSS JAMES/HUDSON BAY AND JUST OFF THE SOUTHEAST CONUS. THIS WILL SET THE STAGE FOR AN ACTIVE WARM FRONT TO BE SITUATED IN THE VICINITY OF THE LOCAL REGION WITH AN INCREASING PROBABILITY FOR SHOWERS AND THUNDERSTORMS. GUIDANCE NUMBERS ARE CLOSE TO WPC GUIDANCE AND WAS FOLLOWED. TUESDAY AND TUESDAY NIGHT... GLOBAL MODEL TRENDS ARE TO STRENGTHEN THE UPPER RIDGE AND RISING SURFACE PRESSURES ACROSS NEW ENGLAND AND INTO PORTIONS OF THE MID ATLANTIC. THIS WILL LIKELY RESULT IN A SLOWER FORWARD PROGRESS OF THE WARM FRONT. AT THIS TIME...IT APPEARS LOCATIONS EAST OF THE HUDSON RIVER WILL SEE A DIMINISHING THREAT FOR WET WEATHER WITH WESTERN AREAS REMAINING UNDER THE INFLUENCE OF THE WARM FRONT. HOWEVER...THE UPPER RIDGE WILL BE BUILDING WITH RISING HEIGHTS WHICH SUGGESTS ANY SHOWERS WILL BE RATHER SCATTERED. IT SHOULD BE RATHER MILD AND A BIT MORE HUMID WITH MANY AREAS CLIMBING WELL INTO THE 60S AND OVERNIGHT LOWS MAINLY INTO THE 50S. WEDNESDAY... THE UPPER RIDGE AXIS SLIDES JUST TO THE EAST WITH LOW LEVEL FLOW TRAJECTORIES FORECAST TO ORIGINATE FROM THE SOUTHEAST. THIS SHOULD ALLOW FOR AN INCREASE INFLUENCE FROM THE ATLANTIC OCEAN TO BRING ABOUT A MARINE INFLUENCE. SO ADDITIONAL CLOUD COVER AND THE THREAT FOR ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM WITH HIGHS ONCE AGAIN WELL INTO THE 60S TO NEAR 70 FOR VALLEY LOCATIONS. WEDNESDAY NIGHT INTO THURSDAY... THIS IS WHERE THE GLOBAL MODELS DIFFER WITH TIMING AND PLACEMENT OF THE APPROACHING COLD FRONT. THE 00Z/GFS REMAINS THE MOST PROGRESSIVE DURING THIS TIME FRAME WITH THE 00Z/ECMWF AND 18Z/0509 DGEX KEEPING THE FRONT FURTHER UPSTREAM AS RIDGE STRENGTHENS OVER THE WESTERN ATLANTIC. THE GGEM IS SOMEWHAT OF A COMPROMISE WITH A LITTLE SLOWER FORWARD PROGRESSION OF THE COLD FRONT BUT STILL KEEPING CLOUDS AND THE THREAT FOR CONVECTION IN THE FORECAST. THURSDAY NIGHT INTO FRIDAY... EVENTUALLY THE UPPER TROUGH UPSTREAM WILL BECOME NEGATIVELY TILTED AND ADVECT IN A HEALTHY AREA OF HIGHER PWATS INTO THE REGION. THIS APPEARS TO BE THE BEST CHANCE FOR A MORE WIDESPREAD SHOWERS/THUNDERSTORMS OR A PERIOD OF RAIN FOR ENTIRE REGION. AT THIS TIME...IT DOES APPEAR THIS WILL BE RATHER PROGRESSIVE TO LIMIT TOO MUCH RAIN BUT THIS WILL NEED TO BE MONITORED CLOSELY. STILL RATHER MILD BUT NOT FULLY REALIZING THE VERY WARM TEMPS ALOFT DUE TO LIMITED MIXING AND CLOUD COVER. OVERALL...PRECIPITATION TRENDS ARE TOWARD ABOVE NORMAL WITH TEMPERATURES NEAR NORMAL. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... THE REGION REMAINS WELL ENTRENCHED IN A MARINE TYPE ENVIRONMENT WITH MVFR/IFR CIGS WITH AN OCCASIONAL DRIZZLE BEING OBSERVED. REGIONAL RADAR REVEALS A BAND OF SCT-BKN SHOWERS OVER WESTERN NEW YORK THAT WILL MOVE ACROSS THE TERMINALS DURING THE OVERNIGHT PERIOD. PER EXPERIMENTAL REFLECTIVITIES FORECASTS...MOST OF THE SHOWERS SHOULD BE DEPARTING BETWEEN 11-13Z AND HAVE FORECAST THIS WITHIN THE TAFS. THERE IS A SMALL CHANCE FOR THUNDER BUT CONFIDENCE IS TOO LOW TO MENTION IN THE FORECAST. IN THE WAKE OF THE SHOWERS...MAIN FRONT REMAINS UPSTREAM AND WITH THE DAYTIME HEATING...ADDITIONAL SHOWERS WILL BE POSSIBLE AS WE WILL PLACE A VCSH IN THE TAFS AT THIS TIME. THE CHANCE FOR SHOWERS WILL QUICKLY DISSIPATE CLOSE TO SUNSET WITH IMPROVING AVIATION CONDITIONS INTO THE SATURDAY EVENING HOURS. WINDS WILL BE SOUTHEAST AROUND 10 KTS WITH SOME OCCASIONAL HIGHER GUSTS...BECOMING SOUTHWESTERLY SATURDAY MORNING AND INCREASING TO AROUND 10-15 KT WITH SOME HIGHER GUSTS INTO THE 20 KT RANGE. OUTLOOK... SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. WEDNESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA. WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. && .FIRE WEATHER... A FRONTAL SYSTEM MOVING ACROSS THE REGION WILL BRING SHOWERS AND THUNDERSTORMS TODAY. RH VALUES WILL ONLY DROP TO 40 TO 55 PERCENT THIS AFTERNOON ALONG WITH S-SW WINDS OF 10 TO 15 MPH. RH VALUES WILL RECOVER TO NEAR 100 PERCENT TONIGHT WITH WEST WINDS OF 5 TO 10 MPH. DRY WEATHER IS EXPECTED ON SUNDAY...WITH RH VALUES DROPPING AS LOW AS 25 TO 35 PERCENT IN THE AFTERNOON HOURS. WINDS ON SUNDAY ARE EXPECTED TO BE WEST AT 10 TO 20 MPH...WITH THE HIGHEST SPEEDS IN THE AFTERNOON. && .HYDROLOGY... NO WIDESPREAD HYDROLOGIC ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. A FRONTAL SYSTEM WILL CONTINUE TO BRING SOME SHOWERS AND THUNDERSTORMS TODAY. THE THREAT FOR RAIN WILL END BY LATE THIS EVENING AS THE COLD FRONT CROSSES THE ENTIRE AREA. HIGH PRESSURE WILL ALLOW FOR DRY WEATHER ON SUNDAY...BUT A WEAK FRONT DROPPING FROM THE NORTH WILL RETURN THE THREAT FOR SOME SCATTERED LIGHT RAIN SHOWERS ON MONDAY. THERE WILL BE A THREAT FOR ADDITIONAL SHOWERS AND THUNDERSTORMS INTO THE MIDDLE OF NEXT WEEK...AS THE FRONTAL BOUNDARY REMAINS NEARBY THE AREA. RAINFALL TODAY MAY ALLOW FOR SOME MINOR RISES ON RIVERS AND STREAMS...BUT ALL WATERWAYS ARE EXPECTED TO REMAIN WITHIN THEIR BANKS. ALTHOUGH PRECIPITATION NEXT WEEK WILL INITIALLY BE SCATTERED AND LIGHT IN NATURE...WE WILL HAVE TO WATCH MODELS TRENDS CLOSELY FOR LATER IN THE WEEK...AS MORE CONCENTRATED AND HEAVIER RAINFALL COULD EVENTUALLY OCCUR SOMEWHERE IN OR NEAR OUR AREA. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS NEAR TERM...FRUGIS SHORT TERM...FRUGIS LONG TERM...BGM AVIATION...BGM FIRE WEATHER...FRUGIS HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
130 AM EDT SAT MAY 10 2014 .SYNOPSIS... A WARM FRONT WILL CONTINUE TO LIFT ACROSS THE REGION DURING THE EARLY MORNING HOURS WITH SOME SHOWERS AND ISOLATED THUNDERSTORMS. LATER DURING THE DAY ON SATURDAY...A WEAK COLD FRONT WILL CROSS THE REGION...BRINGING SOME ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE AREA. HIGH PRESSURE WILL BUILD IN FOR SUNDAY WITH FAIR AND MILD WEATHER. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM EDT...A WARM FRONT OVER CENTRAL NEW YORK IS CONTINUING TO MOVE EASTWARD TOWARDS OUR AREA. THE FRONT...WHICH HAD BEEN STALLED FOR MUCH OF THE DAY FRIDAY OVER WESTERN NEW YORK...IS NOW LOCATED JUST WEST OF OUR CWA. A BATCH OF SHOWERS ASSOCIATED WITH THIS BOUNDARY IS JUST NOW ENTERING THE WESTERN MOHAWK VALLEY AND WESTERN ADIRONDACKS. MUCH OF OUR AREA CONTINUES TO BE REMAIN SOCKED IN WITH LOW STRATUS CLOUDS COURTESY OF A MARINE INFLUENCE WITH A SOUTHEAST FLOW OFF THE OCEAN. THE STRATUS DECK WILL LINGER THROUGH THE OVERNIGHT HOURS WITH A STRONG LOW LEVEL INVERSION IN PLACE. MID LEVEL LAPSE RATES ABOVE THE INVERSION ARE FAIRLY STEEP SO WILL CONTINUE TO MENTION A SLIGHT CHANCE OF THUNDER OVERNIGHT. HI RES MODELS...SUCH AS THE HRRR AND LOCAL WRF...CONTINUE TO INDICATE A FAIRLY WIDESPREAD BATCH OF SHOWERS WITH EMBEDDED THUNDER MOVING ACROSS THE AREA INTO EARLY SATURDAY MORNING ASSOCIATED WITH THE PASSAGE OF THE SURFACE WARM FRONT AND UPPER LEVEL HEIGHT FALLS...SO POPS WILL RISE THROUGH THE OVERNIGHT HOURS. OVERNIGHT TEMPERATURES WILL MAINLY HOLD STEADY AND REMAIN NEAR CURRENT READINGS...WITH UPPER 50S TO MID 60S ACROSS THE REGION. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/... AS THE WEAK COLD FRONT CROSSES THE REGION SATURDAY...THE SHOWERS WILL COME TO AN END ACROSS THE FAR NORTHWEST PART OF THE FORECAST AREA DURING THE AFTERNOON...BUT SHOWER/TSTM ACTIVITY WILL CONTINUE ACROSS THE SOUTH AS A WEAK UPPER LEVEL WAVE RIDES ALONG THE FRONTAL BOUNDARY DURING THE AFTERNOON AND EVENING. THIS WILL KEEP THE THREAT OF SHOWERS/TSTMS IN THESE AREAS GOING WELL INTO SATURDAY EVENING. BY LATE SATURDAY NIGHT THE SHOWERS WILL END IN ALL AREAS. HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY NIGHT IN THE 40S TO LOWER 50S. HIGH PRESSURE WILL BUILD IN ON SUNDAY WITH FAIR AND MILD WEATHER. IT WILL BE MOSTLY SUNNY WITH HIGHS IN THE UPPER 60S TO MID 70S. CLOUDS WILL BEGIN TO INCREASE AGAIN SUNDAY NIGHT AS OVERUNNING MOISTURE QUICKLY OVERSPREADS THE REGION AND A BACK DOOR COLD FRONT TRIES TO SLIP SOUTH INTO THE AREA BY MONDAY MORNING. HOWEVER...NO PCPN HAS BEEN FORECAST FOR SUNDAY NIGHT. LOWS WILL BE IN THE UPPER 40S TO MID 50S. && .LONG TERM /MONDAY THROUGH FRIDAY/... MUCH OF THE LONG TERM PERIOD LOOKS TO FEATURE UNSETTLED WEATHER...ALTHOUGH THERE WILL ALSO BE PERIODS OF PRECIP-FREE CONDITIONS. MONDAY WILL CONTINUE TO BE WARMER THAN NORMAL WITH A WEAK SURFACE TROUGH PROVIDING THE FOCUS FOR SOME WIDELY SCATTERED DIURNAL SHOWERS AND THUNDERSTORMS. TEMPERATURES COULD EVEN APPROACH 80 IN THE HUDSON VALLEY. AS UPPER LEVEL HEIGHTS FLATTEN OUT MONDAY NIGHT INTO TUESDAY...A FEW DISTURBANCES MOVING THROUGH IN THE INCREASING WESTERLY FLOW ALOFT WILL RESULT IN A CONTINUED CHANCE FOR CONVECTION. DUE TO LACK OF SIGNIFICANT INSTABILITY...ONLY GENERIC NON-SEVERE STORMS ARE EXPECTED. TUESDAY ALSO LOOKS TO BE A DAY OF TRANSITION IN TERM OF TEMPERATURES...AS BOTH GFS/ECMWF INDICATING A SIDE-DOOR COLD FRONT WILL PUSH WESTWARD FROM NEW ENGLAND AS THE PATTERN AMPLIFIES WITH HIGH PRESSURE NOSING SOUTHWARD INTO MAINE AND THE CANADIAN MARITIMES. IT LOOKS LIKE THE COLD FRONT WILL APPROACH LATE ON TUESDAY...SO WILL STILL MAINTAIN RELATIVELY WARM MAX TEMPERATURES. HOWEVER...ONCE THE FRONT MOVES THROUGH AN ABRUPT WIND SHIFT ALONG WITH DROPPING TEMPERATURES MAY OCCUR LATE IN THE DAY. AN UPPER LEVEL RIDGE AXIS IS FORECAST TO MOVE ACROSS THE AREA ON WEDNESDAY...ALTHOUGH AT THE SURFACE IT WILL BE CLOUDY AND COOL DUE TO CONTINUED EASTERLY FLOW COMPONENT. WE COULD GET A BREAK IN THE SHOWER ACTIVITY FOR A SHORT TIME AS WELL...ALTHOUGH THERE COULD STILL BE LIGHT RAIN OR DRIZZLE POSSIBLE. MORE WIDESPREAD WET WEATHER COULD DEVELOP THURSDAY INTO FRIDAY...AS A LONG WAVE TROUGH MOVING EASTWARD MAY STALL OVER OUR REGION AS IT ENCOUNTERS A STRONG RIDGE ALONG THE EASTERN SEABOARD. COMPLICATING MATTERS IS ALSO THE POTENTIAL FOR A CUT-OFF LOW TO DEVELOP OVER THE OHIO VALLEY DEPICTED BY THE ECMWF. THIS COULD RESULT IN SIGNIFICANT RAINFALL SOMEWHERE IN THE MID ATLANTIC REGION AND NORTHEAST...BUT IS TOO EARLY TO PINPOINT AT THIS TIME. WILL MAINTAIN CHANCE POPS THROUGH THE PERIOD TO ACCOUNT FOR UNSETTLED CONDITIONS. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... THE REGION REMAINS WELL ENTRENCHED IN A MARINE TYPE ENVIRONMENT WITH MVFR/IFR CIGS WITH AN OCCASIONAL DRIZZLE BEING OBSERVED. REGIONAL RADAR REVEALS A BAND OF SCT-BKN SHOWERS OVER WESTERN NEW YORK THAT WILL MOVE ACROSS THE TERMINALS DURING THE OVERNIGHT PERIOD. PER EXPERIMENTAL REFLECTIVITIES FORECASTS...MOST OF THE SHOWERS SHOULD BE DEPARTING BETWEEN 11-13Z AND HAVE FORECAST THIS WITHIN THE TAFS. THERE IS A SMALL CHANCE FOR THUNDER BUT CONFIDENCE IS TOO LOW TO MENTION IN THE FORECAST. IN THE WAKE OF THE SHOWERS...MAIN FRONT REMAINS UPSTREAM AND WITH THE DAYTIME HEATING...ADDITIONAL SHOWERS WILL BE POSSIBLE AS WE WILL PLACE A VCSH IN THE TAFS AT THIS TIME. THE CHANCE FOR SHOWERS WILL QUICKLY DISSIPATE CLOSE TO SUNSET WITH IMPROVING AVIATION CONDITIONS INTO THE SATURDAY EVENING HOURS. WINDS WILL BE SOUTHEAST AROUND 10 KTS WITH SOME OCCASIONAL HIGHER GUSTS...BECOMING SOUTHWESTERLY SATURDAY MORNING AND INCREASING TO AROUND 10-15 KT WITH SOME HIGHER GUSTS INTO THE 20 KT RANGE. OUTLOOK... SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA. SUNDAY: LOW OPERATIONAL IMPACT.BREEZY NO SIG WX. SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. && .FIRE WEATHER... A NEARLY STATIONARY WARM FRONT ACROSS THE REGION WILL LIFT NORTHEASTWARD BY LATE TONIGHT. ON SATURDAY A WEAK COLD FRONT WILL CROSS THE REGION. THESE FRONTAL BOUNDARIES WILL BE ACCOMPANIED BY SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE WILL BUILD IN FOR SUNDAY WITH FAIR AND MILD WEATHER. FIRE WEATHER CONCERNS THROUGH SATURDAY WILL BE MINIMAL. && .HYDROLOGY... NO WIDESPREAD HYDROLOGIC PROBLEMS ARE ANTICIPATED DURING THE NEXT FIVE DAYS. A NEARLY STATIONARY WARM FRONT ACROSS THE REGION WILL LIFT NORTHEASTWARD BY LATE TONIGHT. ON SATURDAY A WEAK COLD FRONT WILL CROSS THE REGION. THESE FRONTAL BOUNDARIES WILL BE ACCOMPANIED BY SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE WILL BUILD IN FOR SUNDAY WITH FAIR AND MILD WEATHER. BASIN AVERAGE RAINFALL FROM THESE FRONTAL BOUNDARIES WILL GENERALLY BE BETWEEN A QUARTER AND HALF AN INCH THROUGH SATURDAY NIGHT... ALTHOUGH LOCALIZED AMOUNTS OF AN INCH OR MORE ARE POSSIBLE WHERE THUNDERSTORMS OCCUR. WHILE THERE MAY BE SOME MINOR RISES ON RIVERS AND STREAMS...ALL WATERWAYS ARE EXPECTED TO STAY WITHIN THEIR BANKS...AND NO FLOODING IS ANTICIPATED AT THIS TIME. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/GJM NEAR TERM...FRUGIS/GJM/JPV SHORT TERM...GJM LONG TERM...JPV AVIATION...BGM FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
915 PM EDT SUN MAY 11 2014 .DISCUSSION... TONIGHT-MON...A POCKET OF DRIER AIR WAS ADVECTING IN FROM THE EAST/SOUTHEAST AS EVIDENCED BY BLENDED TOTAL PRECIPITABLE WATER VALUES AROUND ONE INCH OVER THE SOUTHERN PART OF THE STATE. SURFACE HIGH PRESSURE RIDGE WILL NUDGE JUST A LITTLE TO THE NORTH WHICH WILL BACK SURFACE WINDS TO THE EAST ON MON. THE PRESSURE GRADIENT WILL START TO TIGHTEN A BIT TOO AS EASTERLY WAVE MOVES ACROSS THE SOUTHERN BAHAMAS/CUBA. THEREFORE IT WILL GET ON THE WINDY SIDE ALONG THE SPACE/TREASURE COAST BEHIND THE SEA BREEZE ON MON. THE MAIN MOISTENING WITH THE EASTERLY WAVE WILL STAY WELL SOUTH OF THE AREA ON MON BUT WITH INCREASING EAST FLOW...EXPECT A FEW ATLANTIC CLOUD LINES TO SET UP. THE NAM/GFS ARE DRY TONIGHT/MON BUT THE HRRR AND LOCAL WRF INDICATE A FEW SHOWERS LATE TONIGHT ACROSS THE SOUTH. THEREFORE WILL RETAIN A LESS THAN 20 PERCENT POP THERE LATE TONIGHT. THE INCREASING ONSHORE FLOW WILL CAUSE ANY EAST/WEST COAST BOUNDARY INTERACTION LATE MON TO OCCUR OVER WEST CENTRAL FLORIDA. MOS POPS ARE BELOW 10 PERCENT...SO OTHER THAN A SLIGHT MORNING COASTAL POP POSSIBLE IN THE SOUTH...IT LOOKS LIKE A DRY DAY. FORECAST SOUNDINGS CONTINUE TO SHOW THAT THERE WILL BE SOME CIRRUS BUT STILL EXPECT PARTLY SUNNY SKIES. LITTLE CHANGE IN MAX TEMPS WITH MID 80S ALONG THE COAST AND AROUND 90 ACROSS THE INTERIOR. && .AVIATION... VFR. BREEZY CONDITIONS WILL RETURN BEHIND THE SEA BREEZE ON MON WITH GUSTS 20-25 KNOTS INDICATED KMLB-KSUA. && .MARINE... TONIGHT/MON...THERE WILL BE A GRADUAL DETERIORATION OF CONDITIONS FOR SMALL CRAFT. THE PRESSURE GRADIENT WILL TIGHTEN UP A BIT AND WINDS WILL BACK TO EASTERLY BY MON. EXERCISE CAUTION CONDITIONS LOOK LIKELY ON MON IN THE SOUTH. THE CENTRAL ZONES SHOULD BE 10-15 KNOTS EARLY MON BUT 15-17 KNOTS BY LATE AFTERNOON. THE NORTHERN ZONES LOOK CLOSE TO 10 KNOTS EARLY MON THEN CLOSE TO 15 KNOTS BY LATE DAY. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECASTS...LASCODY IMPACT WX...WEITLICH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1027 PM EDT SUN MAY 11 2014 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PREVAIL INTO THE MIDDLE OF THE WEEK. A COLD FRONT WILL PUSH THROUGH THE REGION LATER THURSDAY OR EARLY FRIDAY. COOLER AND DRIER HIGH PRESSURE WILL THEN BUILD INTO THE AREA THROUGH NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... PER LATE SUNDAY EVENING RADAR TRENDS...APPEARS THAT CONVECTION HAS ENDED FOR THE NIGHT ACROSS INTERIOR SE GA. ADJUSTED FORECASTS ACCORDINGLY. OVERNIGHT...THE RUC13 SUGGESTS THAT ADDITIONAL SHOWERS/THUNDERSTORMS WILL DEVELOP ACROSS SC COUNTIES LATE TONIGHT...ESPECIALLY CLOSE TO THE COAST. EVEN ACCOUNTING FOR DIURNAL STABILIZATION...THE 00Z KCHS SOUNDING REVEALED AMPLE INSTABILITY TO SUPPORT ADDITIONAL CONVECTION. HOWEVER...A MECHANISM TO INITIATE ADDITIONAL DEEP MOIST CONVECTION IS LACKING. ALSO...OTHER GUIDANCE INCLUDING THE 00Z NAM DOES NOT INDICATE ANY NEW CONVECTION OVERNIGHT. THUS...OVERNIGHT POPS REMAIN BELOW 15 PERCENT WITH NO MENTION OF PRECIPITATION ACROSS THE FORECAST AREA. LIGHT WINDS...CLEARING SKIES AND LOW LEVEL MOISTURE WILL SUPPORT PATCHY STRATUS/FOG OVERNIGHT...ESPECIALLY WHERE RAINFALL OCCURRED SUNDAY AFTERNOON/EVENING. TEMPERATURES WILL BOTTOM OUT IN THE UPPER 60S/LOWER 70S MOST AREAS. A FEW INLAND LOCATIONS COULD DROP INTO THE MIDDLE 60S TOWARD DAYBREAK. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... MONDAY THROUGH WEDNESDAY...THE PATTERN WILL BE DOMINATED WITH UPPER RIDGING POSITIONED ACROSS THE SOUTHEAST U.S. WITH THE AREA LOCATED ALONG THE WESTERN FRINGES OF ATLANTIC HIGH PRESSURE. THIS SYNOPTIC SETUP WILL FAVOR TYPICAL EARLY SUMMER WEATHER...FEATURING THE DEVELOPMENT OF DIURNALLY DRIVEN SHOWERS/TSTMS EACH AFTERNOON AND EVENING...MAINLY ALONG AND AHEAD OF THE SEA BREEZE. GIVEN THE STRENGTH OF THE UPPER RIDGE...POPS WILL BE CAPPED AT 20-30 PERCENT AND MAINLY CLUSTERED WEST OF THE I-95 CORRIDOR. HIGHS WILL GENERALLY TOP OUT IN THE UPPER 80S TO AROUND 90 INLAND WITH MID 80S JUST INLAND FROM THE BEACHES. OVERNIGHT LOWS WILL DROP INTO THE MID-UPPER 60S EACH NIGHT...LOCALLY WARMER ALONG THE BEACHES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... RAIN CHANCES WILL BE ON THE INCREASE WEDNESDAY NIGHT AND THURSDAY AS DEEP MOISTURE MOVES IN AHEAD OF A COLD FRONT. THERE REMAINS SOME UNCERTAINTY REGARDING THE EXACT TIMING OF THE FRONTAL PASSAGE AND THIS WILL IMPACT THE AMOUNT OF INSTABILITY AVAILABLE FOR THUNDERSTORMS. DEEP LAYER SHEAR APPEARS SUBSTANTIAL ENOUGH TO SUPPORT SEVERE STORMS SO WILL HAVE TO MONITOR THIS THROUGH THE WEEK. WILL ALSO KEEP WATCHING A WAVE OF LOW PRESSURE TRACKING ACROSS THE NORTHERN CARIBBEAN TOWARD THE BAHAMAS WHICH SHOULD REMAIN OFFSHORE THE SOUTHEAST COAST BUT COULD BRING A BIT MORE MOISTURE TO THE REGION. DRIER AND UNSEASONABLY COOL AIR LOOKS TO MOVE IN FRIDAY AND SATURDAY BEFORE ANOTHER COLD FRONT POSSIBLY AFFECTS THE AREA SUNDAY. SOME INLAND LOCALES COULD SEE MIN TEMPS IN THE UPPER 40S OVER THE WEEKEND. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL UNTIL LATER TONIGHT. THEN...LOW LEVEL MOISTURE ENHANCED BY RAINFALL WILL SUPPORT AT LEAST OCCASIONAL MVFR CONDITIONS AT BOTH TERMINALS...AND BRIEF IFR OR LOWER CONDITIONS CANNOT BE RULED OUT. VFR CONDITIONS ARE THEN EXPECTED BY MID-MORNING MONDAY THROUGH THE REMAINDER OF THE 00Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...GENERALLY VFR THROUGH WED WITH THE PROBABILITY OF ANY SIGNIFICANT IMPACTS LESS THAN 30 PERCENT. A COLD FRONT PUSHING THROUGH THURSDAY OR THURSDAY NIGHT WILL LIKELY BRING MVFR OR LOWER CIGS/VSBYS DUE TO SHOWERS AND THUNDERSTORMS. && .MARINE... TRANQUIL CONDITIONS ARE EXPECTED ACROSS COASTAL WATERS OVERNIGHT. SOUTHERLY WINDS GENERALLY LESS THAN 15 KT AND SEAS 1-3 FT WILL PREVAIL. MONDAY THROUGH FRIDAY...NO SIGNIFICANT IMPACTS EXPECTED THROUGH WED WITH ATLANTIC HIGH PRESSURE DOMINATING. SOUTHERLY WIND REGIME WILL CONTINUE WITH SPEEDS GENERALLY 15 KT OR LESS WITH SIGNIFICANT WAVE HEIGHTS 3 FT OR LESS WITHIN 20 NM AND UP TO 4 FT OVER THE GA 20-60 NM ZONE. THERE IS SOME UNCERTAINTY REGARDING THE STRENGTH AND TIMING OF A COLD FRONT THURSDAY...ALONG WITH A WAVE OF LOW PRESSURE TRACKING THROUGH THE NORTHERN CARIBBEAN AND BAHAMAS. ANY WAVE SHOULD REMAIN OFFSHORE GIVEN THE APPROACHING FRONT BUT WINDS AND SEAS COULD STILL BE HIGHER THAN CURRENTLY FORECAST DEPENDING ON THE STRENGTH OF THE FRONT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...SPR SHORT TERM...ST LONG TERM...RJB AVIATION...SPR/ST MARINE...SPR/ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
922 PM EDT SUN MAY 11 2014 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PREVAIL INTO THE MIDDLE OF THE WEEK BEFORE A COLD FRONT LIKELY PUSHES THROUGH THURSDAY OR THURSDAY NIGHT. UNSEASONABLY COOL HIGH PRESSURE WILL THEN MOVE IN THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS WILL CONTINUE TO DEVELOP AND DISSIPATE ALONG INTERSECTING MESOSCALE BOUNDARIES ACROSS INTERIOR SOUTHEAST GEORGIA THIS EVENING...ESPECIALLY ALONG THE I-16 CORRIDOR WELL WEST OF I-95. MLCAPES 1500-2000 J/KG AND DOWNDRAFT CAPES AROUND 1000 J/KG COULD SUPPORT LOCALLY GUSTY WINDS...WHILE SLOW STORM PROPAGATION COULD SUPPORT LOCALLY HEAVY RAIN. THEN... POPS IN THIS AREA FALL BELOW 15 PERCENT BY MIDNIGHT AS BOUNDARIES PUSH INLAND AND DIURNAL STABILIZATION CONTINUES. OVERNIGHT...THE RUC13 SUGGESTS THAT ADDITIONAL SHOWERS/THUNDERSTORMS WILL DEVELOP ACROSS SC COUNTIES...ESPECIALLY CLOSE TO THE COAST. THE 00Z KCHS SOUNDING REVEALED AMPLE INSTABILITY TO SUPPORT ADDITIONAL CONVECTION...BUT A MECHANISM TO INITIATE ADDITIONAL DEEP MOIST CONVECTION IS LACKING. ALSO...OTHER HIGH RESOLUTION GUIDANCE DOES NOT INDICATE ANY NEW CONVECTION OVERNIGHT. THUS...OVERNIGHT POPS REMAIN BELOW 15 PERCENT WITH NO MENTION OF PRECIPITATION ACROSS THE FORECAST AREA. LIGHT WINDS...CLEARING SKIES AND LOW LEVEL MOISTURE WILL SUPPORT PATCHY FOG OVERNIGHT...ESPECIALLY WHERE RAINFALL OCCURRED SUNDAY AFTERNOON/EVENING. TEMPERATURES WILL BOTTOM OUT IN THE UPPER 60S/LOWER 70S MOST AREAS. A FEW INLAND LOCATIONS COULD DROP INTO THE MIDDLE 60S TOWARD DAYBREAK. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... MONDAY THROUGH WEDNESDAY...THE PATTERN WILL BE DOMINATED WITH UPPER RIDGING POSITIONED ACROSS THE SOUTHEAST U.S. WITH THE AREA LOCATED ALONG THE WESTERN FRINGES OF ATLANTIC HIGH PRESSURE. THIS SYNOPTIC SETUP WILL FAVOR TYPICAL EARLY SUMMER WEATHER...FEATURING THE DEVELOPMENT OF DIURNALLY DRIVEN SHOWERS/TSTMS EACH AFTERNOON AND EVENING...MAINLY ALONG AND AHEAD OF THE SEA BREEZE. GIVEN THE STRENGTH OF THE UPPER RIDGE...POPS WILL BE CAPPED AT 20-30 PERCENT AND MAINLY CLUSTERED WEST OF THE I-95 CORRIDOR. HIGHS WILL GENERALLY TOP OUT IN THE UPPER 80S TO AROUND 90 INLAND WITH MID 80S JUST INLAND FROM THE BEACHES. OVERNIGHT LOWS WILL DROP INTO THE MID-UPPER 60S EACH NIGHT...LOCALLY WARMER ALONG THE BEACHES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... RAIN CHANCES WILL BE ON THE INCREASE WEDNESDAY NIGHT AND THURSDAY AS DEEP MOISTURE MOVES IN AHEAD OF A COLD FRONT. THERE REMAINS SOME UNCERTAINTY REGARDING THE EXACT TIMING OF THE FRONTAL PASSAGE AND THIS WILL IMPACT THE AMOUNT OF INSTABILITY AVAILABLE FOR THUNDERSTORMS. DEEP LAYER SHEAR APPEARS SUBSTANTIAL ENOUGH TO SUPPORT SEVERE STORMS SO WILL HAVE TO MONITOR THIS THROUGH THE WEEK. WILL ALSO KEEP WATCHING A WAVE OF LOW PRESSURE TRACKING ACROSS THE NORTHERN CARIBBEAN TOWARD THE BAHAMAS WHICH SHOULD REMAIN OFFSHORE THE SOUTHEAST COAST BUT COULD BRING A BIT MORE MOISTURE TO THE REGION. DRIER AND UNSEASONABLY COOL AIR LOOKS TO MOVE IN FRIDAY AND SATURDAY BEFORE ANOTHER COLD FRONT POSSIBLY AFFECTS THE AREA SUNDAY. SOME INLAND LOCALES COULD SEE MIN TEMPS IN THE UPPER 40S OVER THE WEEKEND. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL PREVAIL UNTIL LATER TONIGHT. THEN...LOW LEVEL MOISTURE ENHANCED BY RAINFALL WILL SUPPORT AT LEAST OCCASIONAL MVFR CONDITIONS AT BOTH TERMINALS...AND BRIEF IFR OR LOWER CONDITIONS CANNOT BE RULED OUT. VFR CONDITIONS ARE THEN EXPECTED BY MID-MORNING MONDAY THROUGH THE REMAINDER OF THE 00Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...GENERALLY VFR THROUGH WED WITH THE PROBABILITY OF ANY SIGNIFICANT IMPACTS LESS THAN 30 PERCENT. A COLD FRONT PUSHING THROUGH THURSDAY OR THURSDAY NIGHT WILL LIKELY BRING MVFR OR LOWER CIGS/VSBYS DUE TO SHOWERS AND THUNDERSTORMS. && .MARINE... TRANQUIL CONDITIONS ARE EXPECTED ACROSS COASTAL WATERS OVERNIGHT. SOUTHERLY WINDS GENERALLY LESS THAN 15 KT AND SEAS 1-3 FT WILL PREVAIL. MONDAY THROUGH FRIDAY...NO SIGNIFICANT IMPACTS EXPECTED THROUGH WED WITH ATLANTIC HIGH PRESSURE DOMINATING. SOUTHERLY WIND REGIME WILL CONTINUE WITH SPEEDS GENERALLY 15 KT OR LESS WITH SIGNIFICANT WAVE HEIGHTS 3 FT OR LESS WITHIN 20 NM AND UP TO 4 FT OVER THE GA 20-60 NM ZONE. THERE IS SOME UNCERTAINTY REGARDING THE STRENGTH AND TIMING OF A COLD FRONT THURSDAY...ALONG WITH A WAVE OF LOW PRESSURE TRACKING THROUGH THE NORTHERN CARIBBEAN AND BAHAMAS. ANY WAVE SHOULD REMAIN OFFSHORE GIVEN THE APPROACHING FRONT BUT WINDS AND SEAS COULD STILL BE HIGHER THAN CURRENTLY FORECAST DEPENDING ON THE STRENGTH OF THE FRONT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...SPR SHORT TERM...ST LONG TERM...RJB AVIATION...SPR/ST MARINE...SPR/ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
416 PM EDT SAT MAY 10 2014 .SYNOPSIS... HIGH PRESSURE WILL RIDGE INTO THE FORECAST AREA FROM THE ATLANTIC TROUGH MONDAY. SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL LINGER. THE MOISTURE AND HEATING MAY HELP SUPPORT SHOWERS AND THUNDERSTORMS...BUT THE RIDGING SHOULD GENERALLY KEEP COVERAGE ISOLATED. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... THIS AFTERNOON...MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT...A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH...PLUS HEATING WILL HELP SUPPORT SHOWERS AND THUNDERSTORMS THIS AFTERNOON. EXPECT COVERAGE WILL REMAIN LIMITED BECAUSE OF A LACK OF DEEP MOISTURE. THE LATEST LAPS SOUNDINGS INDICATED JUST SHALLOW MOISTURE. THE LATEST HRRR SUPPORTED SCATTERED COVERAGE. OUR FORECAST OF CHANCE POPS APPEARS ON TRACK. LIMITED MOISTURE WILL PROBABLY KEEP THUNDERSTORMS WEAK...BUT SEVERE THUNDERSTORMS ARE NOT OUT OF THE QUESTION. EARLY AFTERNOON SURFACE-BASED LI/S WERE NEAR -5. THE KCAE 88D SHOWED UNI- DIRECTIONAL SHEAR WITH WINDS INCREASING TO 30 KNOTS AT 5000 FEET. THIS INSTABILITY AND SHEAR PLUS EVAPORATIVE COOLING IN THE MID- LEVELS POTENTIALLY AIDING DOWNDRAFTS COULD POSSIBLY HELP SUPPORT NEAR-SEVERE WIND GUSTS IN STRONGER THUNDERSTORMS. WET-BULB ZERO HEIGHTS NEAR 10000 FEET ALSO SUPPORT HAIL. TONIGHT...THUNDERSTORMS MAY LINGER THIS EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT COUPLED WITH WEAK INSTABILITY. THE HRRR INDICATED SCATTERED COVERAGE IN THE EVENING... WITH SOME CONCENTRATION IN THE SOUTH PART. AN AVERAGE OF THE GFS AND NAM MOS SUPPORTED POPS AROUND 20 PERCENT. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... THE GFS AND ESPECIALLY THE NAM SHOW MORE MOISTURE LINGERING MAINLY IN THE SOUTHEAST SECTION SUNDAY THROUGH MONDAY NIGHT. A WELL- DEFINED SURFACE FEATURE APPEARS TO BE LACKING. ALOFT...THE MODELS SHOW RISING H5 HEIGHT. WE USED THE LOWER GUIDANCE POPS. BELIEVE ANY SHOWERS AND THUNDERSTORMS WILL BE ISOLATED AND MAINLY TIED TO HEATING. KEPT HIGHS SLIGHTLY HIGHER THAN THE MOS GUIDANCE GIVEN RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. USED THE MOS CONSENSUS FOR THE LOW TEMPERATURES. && .LONG TERM /TUESDAY THROUGH SATURDAY/... MODELS IN GENERAL AGREEMENT ON TUESDAY WITH BERMUDA HIGH IN PLACE FOR THE SE US AND AN UPPER TROUGH OVER THE MID PART OF THE COUNTRY. THE PROGRESSION EASTWARD OF THE UPPER TROUGH HAS SLOWED IN LATEST MODEL RUNS. WHILE THE HIGH OFF THE COAST WILL DOMINATE INTO MID WEEK...INCREASING MOISTURE AND TEMPERATURES WILL RESULT IN A CHANCE OF A FEW AFTERNOON THUNDERSTORMS TUESDAY. THE DIURNAL ACTIVITY WILL DIMINISH OVERNIGHT AND THEN THE CHANCE OF AFTERNOON THUNDERSTORMS INCREASES WEDNESDAY. AS THE NEXT SYSTEM SLOWLY APPROACHES THE AREA AND MOVES THROUGH ON THURSDAY EXPECT THE CHANCE OF RAIN TO CONTINUE AND ATTM EXPECT THE HIGHEST CHANCE TO BE THURSDAY AFTERNOON/EVENING. WILL HAVE TO CONTINUE TO WATCH THE TIMING AND PROGRESSION OF THE UPPER TROUGH. TEMPERATURES AHEAD OF THE NEXT SYSTEM SHOULD BE ABOVE NORMAL IN THE UPPER 80S TUESDAY AND WEDNESDAY AND THEN AS CLOUDS AND PRECIPITATION MOVE IN...HIGHS WILL BE SOMEWHAT COOLER THE REMAINDER OF THE WEEK IN THE UPPER 70S TO AROUND 80. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FONT COMBINED WITH HEATING AND A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH HAS HELPED SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS. BELIEVE COVERAGE WILL REMAIN SCATTERED BECAUSE OF LIMITED MOISTURE. LINGERING THUNDERSTORMS WILL LIKELY DISSIPATE LATER THIS EVENING WITH THE LOSS OF HEATING. LIGHT WIND...SOME LOW-LEVEL MOISTURE AND NOCTURNAL COOLING MAY HELP CAUSE FOG LATE TONIGHT. SOME OF THE NAM AND GFS MOS INDICATE MVFR OR IFR FOG WITH THE GREATER RESTRICTIONS AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. HEATING AND MIXING SHOULD DISSIPATE ANY FOG BY 14Z. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH WEDNESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
203 PM EDT SAT MAY 10 2014 .SYNOPSIS... HIGH PRESSURE WILL RIDGE INTO THE FORECAST AREA FROM THE ATLANTIC TROUGH MONDAY. SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL LINGER. THE MOISTURE AND HEATING MAY HELP SUPPORT SHOWERS AND THUNDERSTORMS...BUT THE RIDGING SHOULD GENERALLY KEEP COVERAGE ISOLATED. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT...A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH...PLUS HEATING WILL HELP SUPPORT SHOWERS AND THUNDERSTORMS THIS AFTERNOON. EXPECT COVERAGE WILL REMAIN LIMITED BECAUSE OF A LACK OF DEEP MOISTURE. THE LATEST LAPS SOUNDINGS INDICATED JUST SHALLOW MOISTURE. THE LATEST HRRR SUPPORTED SCATTERED COVERAGE. OUR FORECAST OF CHANCE POPS APPEARS ON TRACK. LIMITED MOISTURE WILL PROBABLY KEEP THUNDERSTORMS WEAK...BUT SEVERE THUNDERSTORMS ARE NOT OUT OF THE QUESTION. EARLY AFTERNOON SURFACE-BASED LI/S WERE NEAR -5. THE KCAE 88D SHOWED UNI- DIRECTIONAL SHEAR WITH WINDS INCREASING TO 30 KNOTS AT 5000 FEET. THIS INSTABILITY AND SHEAR PLUS EVAPORATIVE COOLING IN THE MID- LEVELS POTENTIALLY AIDING DOWNDRAFTS COULD POSSIBLY HELP SUPPORT NEAR-SEVERE WIND GUSTS IN STRONGER THUNDERSTORMS. WET-BULB ZERO HEIGHTS NEAR 10000 FEET ALSO SUPPORT HAIL. TONIGHT...THUNDERSTORMS MAY LINGER THIS EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT COUPLED WITH WEAK INSTABILITY. THE HRRR INDICATED SCATTERED COVERAGE IN THE EVENING... WITH SOME CONCENTRATION IN THE SOUTH PART. AN AVERAGE OF THE GFS AND NAM MOS SUPPORTED POPS AROUND 20 PERCENT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE GFS AND ESPECIALLY THE NAM SHOW MORE MOISTURE LINGERING MAINLY IN THE SOUTHEAST SECTION SUNDAY THROUGH MONDAY NIGHT. A WELL- DEFINED SURFACE FEATURE APPEARS TO BE LACKING. ALOFT...THE MODELS SHOW RISING H5 HEIGHT. WE USED THE LOWER GUIDANCE POPS. BELIEVE ANY SHOWERS AND THUNDERSTORMS WILL BE ISOLATED AND MAINLY TIED TO HEATING. KEPT HIGHS SLIGHTLY HIGHER THAN THE MOS GUIDANCE GIVEN RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. USED THE MOS CONSENSUS FOR THE LOW TEMPERATURES. && .LONG TERM /TUESDAY THROUGH FRIDAY/... MODELS IN GENERAL AGREEMENT ON TUESDAY WITH BERMUDA HIGH IN PLACE FOR THE SE US AND AN UPPER TROUGH OVER THE MID PART OF THE COUNTRY. THE PROGRESSION EASTWARD OF THE UPPER TROUGH HAS SLOWED IN LATEST MODEL RUNS. WHILE THE HIGH OFF THE COAST WILL DOMINATE INTO MID WEEK...INCREASING MOISTURE AND TEMPERATURES WILL RESULT IN A CHANCE OF A FEW AFTERNOON THUNDERSTORMS TUESDAY. THE DIURNAL ACTIVITY WILL DIMINISH OVERNIGHT AND THEN THE CHANCE OF AFTERNOON THUNDERSTORMS INCREASES WEDNESDAY. AS THE NEXT SYSTEM SLOWLY APPROACHES THE AREA AND MOVES THROUGH ON THURSDAY EXPECT THE CHANCE OF RAIN TO CONTINUE AND ATTM EXPECT THE HIGHEST CHANCE TO BE THURSDAY AFTERNOON/EVENING. WILL HAVE TO CONTINUE TO WATCH THE TIMING AND PROGRESSION OF THE UPPER TROUGH. TEMPERATURES AHEAD OF THE NEXT SYSTEM SHOULD BE ABOVE NORMAL IN THE UPPER 80S TUESDAY AND WEDNESDAY AND THEN AS CLOUDS AND PRECIPITATION MOVE IN...HIGHS WILL BE SOMEWHAT COOLER THE REMAINDER OF THE WEEK IN THE UPPER 70S TO AROUND 80. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL BE IN THE FORECAST AREA THIS AFTERNOON AND EVENING. THE MOISTURE COMBINED WITH A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH WILL LIKELY SUPPORT THUNDERSTORMS. HOWEVER...THE MOISTURE WILL REMAIN LIMITED AND THE FORCING WILL BE WEAK. EXPECT SCATTERED COVERAGE. THE CHANCE OF THUNDERSTORMS IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. LIGHT WIND...SOME LOW-LEVEL MOISTURE AND NOCTURNAL COOLING MAY HELP CAUSE FOG LATE TONIGHT. SOME OF THE NAM AND GFS MOS INDICATE MVFR OR IFR FOG WITH THE GREATER RESTRICTIONS AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH WEDNESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
113 PM EDT SAT MAY 10 2014 .SYNOPSIS... HIGH PRESSURE WILL RIDGE INTO THE FORECAST AREA FROM THE ATLANTIC TROUGH MONDAY. SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL LINGER. THE MOISTURE AND HEATING MAY HELP SUPPORT SHOWERS AND THUNDERSTORMS...BUT THE RIDGING SHOULD GENERALLY KEEP COVERAGE ISOLATED. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT...A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH...PLUS HEATING WILL HELP SUPPORT SHOWERS AND THUNDERSTORMS THIS AFTERNOON. EXPECT COVERAGE WILL REMAIN LIMITED BECAUSE OF A LACK OF DEEP MOISTURE. THE LATEST LAPS SOUNDINGS INDICATED JUST SHALLOW MOISTURE. THE LATEST HRRR SUPPORTED SCATTERED COVERAGE. OUR FORECAST OF CHANCE POPS APPEARS ON TRACK. LIMITED MOISTURE WILL PROBABLY KEEP THUNDERSTORMS WEAK...BUT SEVERE THUNDERSTORMS ARE NOT OUT OF THE QUESTION. EARLY AFTERNOON SURFACE-BASED LI/S WERE NEAR -5. THE KCAE 88D SHOWED UNI- DIRECTIONAL SHEAR WITH WINDS INCREASING TO 30 KNOTS AT 5000 FEET. THIS INSTABILITY AND SHEAR PLUS EVAPORATIVE COOLING IN THE MID- LEVELS POTENTIALLY AIDING DOWNDRAFTS COULD POSSIBLY HELP SUPPORT NEAR-SEVERE WIND GUSTS IN STRONGER THUNDERSTORMS. WET-BULB ZERO HEIGHTS NEAR 10000 FEET ALSO SUPPORT HAIL. TONIGHT...THUNDERSTORMS MAY LINGER THIS EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT COUPLED WITH WEAK INSTABILITY. THE HRRR INDICATED SCATTERED COVERAGE IN THE EVENING... WITH SOME CONCENTRATION IN THE SOUTH PART. AN AVERAGE OF THE GFS AND NAM MOS SUPPORTED POPS AROUND 20 PERCENT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE GFS AND ESPECIALLY THE NAM SHOW MORE MOISTURE LINGERING MAINLY IN THE SOUTHEAST SECTION SUNDAY THROUGH MONDAY NIGHT. A WELL- DEFINED SURFACE FEATURE APPEARS TO BE LACKING. ALOFT...THE MODELS SHOW RISING H5 HEIGHT. WE USED THE LOWER GUIDANCE POPS. BELIEVE ANY SHOWERS AND THUNDERSTORMS WILL BE ISOLATED AND MAINLY TIED TO HEATING. KEPT HIGHS SLIGHTLY HIGHER THAN THE MOS GUIDANCE GIVEN RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. USED THE MOS CONSENSUS FOR THE LOW TEMPERATURES. && .LONG TERM /TUESDAY THROUGH FRIDAY/... MODELS IN GENERAL AGREEMENT ON TUESDAY WITH BERMUDA HIGH IN PLACE FOR THE SE US AND AN UPPER TROUGH OVER THE MID PART OF THE COUNTRY. THE PROGRESSION EASTWARD OF THE UPPER TROUGH HAS SLOWED IN LATEST MODEL RUNS. WHILE THE HIGH OFF THE COAST WILL DOMINATE INTO MID WEEK...INCREASING MOISTURE AND TEMPERATURES WILL RESULT IN A CHANCE OF A FEW AFTERNOON THUNDERSTORMS TUESDAY. THE DIURNAL ACTIVITY WILL DIMINISH OVERNIGHT AND THEN THE CHANCE OF AFTERNOON THUNDERSTORMS INCREASES WEDNESDAY. AS THE NEXT SYSTEM SLOWLY APPROACHES THE AREA AND MOVES THROUGH ON THURSDAY EXPECT THE CHANCE OF RAIN TO CONTINUE AND ATTM EXPECT THE HIGHEST CHANCE TO BE THURSDAY AFTERNOON/EVENING. WILL HAVE TO CONTINUE TO WATCH THE TIMING AND PROGRESSION OF THE UPPER TROUGH. TEMPERATURES AHEAD OF THE NEXT SYSTEM SHOULD BE ABOVE NORMAL IN THE UPPER 80S TUESDAY AND WEDNESDAY AND THEN AS CLOUDS AND PRECIPITATION MOVE IN...HIGHS WILL BE SOMEWHAT COOLER THE REMAINDER OF THE WEEK IN THE UPPER 70S TO AROUND 80. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL BE IN THE FORECAST AREA THIS AFTERNOON AND EVENING. THE MOISTURE COMBINED WITH A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH WILL LIKELY SUPPORT THUNDERSTORMS. HOWEVER...THE MOISTURE WILL REMAIN LIMITED AND THE FORCING WILL BE WEAK. EXPECT SCATTERED COVERAGE. THE CHANCE OF THUNDERSTORMS IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. LIGHT WIND...SOME LOW-LEVEL MOISTURE AND NOCTURNAL COOLING MAY HELP CAUSE FOG LATE TONIGHT. SOME OF THE NAM AND GFS MOS INDICATE MVFR OR IFR FOG WITH THE GREATER RESTRICTIONS AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH WEDNESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1115 AM EDT SAT MAY 10 2014 .SYNOPSIS... MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL SHIFT EAST OF THE FORECAST AREA TONIGHT. HIGH PRESSURE EXTENDING INTO THE FORECAST AREA FROM THE ATLANTIC WILL DOMINATE SUNDAY THROUGH TUESDAY. MOISTURE WILL INCREASE WEDNESDAY AHEAD OF A FRONTAL SYSTEM. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT...A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH...PLUS HEATING WILL HELP SUPPORT SHOWERS AND THUNDERSTORMS THIS AFTERNOON. EXPECT COVERAGE WILL REMAIN LIMITED BECAUSE OF A LACK OF DEEP MOISTURE. THE LATEST LAPS SOUNDINGS INDICATED JUST SHALLOW MOISTURE. THE LATEST HRRR SUPPORTED SCATTERED COVERAGE. OUR FORECAST OF CHANCE POPS APPEARS ON TRACK. LIMITED MOISTURE WILL PROBABLY KEEP THUNDERSTORMS WEAK...BUT SEVERE THUNDERSTORMS ARE NOT OUT OF THE QUESTION. LATE MORNING SURFACE- BASED LI/S WERE NEAR -4. EXPECT AFTERNOON VALUES AROUND -5. THE KCAE 88D SHOWED UNI-DIRECTIONAL SHEAR WITH WINDS INCREASING TO 30 KNOTS AT 5000 FEET. THIS INSTABILITY AND SHEAR PLUS EVAPORATIVE COOLING IN THE MID-LEVELS POTENTIALLY AIDING DOWNDRAFTS COULD POSSIBLY HELP SUPPORT NEAR-SEVERE WIND GUSTS IN STRONGER THUNDERSTORMS. WET-BULB ZERO HEIGHTS NEAR 10000 FEET ALSO SUPPORT HAIL. TONIGHT...THUNDERSTORMS MAY LINGER THIS EVENING ASSOCIATED WITH CONVERGENCE INTO THE WEAK LEE-SIDE TROUGH AND BAND OF MOISTURE FROM THE REMNANTS OF THE FRONT COUPLED WITH WEAK INSTABILITY. THE GUIDANCE CONSENSUS SUPPORTS POPS AROUND 20 PERCENT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE MODELS INDICATE RISING HEIGHTS SUNDAY INTO SUNDAY NIGHT. THE SURFACE SUBTROPICAL ATLANTIC RIDGE WILL SLOWLY BUILD WESTWARD INTO THE SOUTHEASTERN STATES. ENSEMBLE POPS REMAIN BELOW NORMAL... THOUGH CANNOT RULE OUT ISOLATED THUNDERSTORMS MAINLY ASSOCIATED WITH HEATING MONDAY AND TUESDAY. KEPT HIGHS SLIGHTLY HIGHER THAN MOS GUIDANCE GIVEN RECENT VERIFICATION...UPPER RIDGING...AND THE DRY ENVIRONMENTAL CONDITIONS. THE MOS CONSENSUS WAS USED FOR OVERNIGHT LOWS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... MODELS ARE IN RELATIVELY GOOD AGREEMENT THROUGH TUESDAY...THEN BEGIN TO DIFFER LATER IN THE WEEK. THE GFS MOVES THE UPPER LEVEL TROF AND SFC CDFNT OUT EARLIER WHILE THE ECMWF IS SLOWER BY 24HRS. AS A RESULT CHANCES OF RAIN AND TEMPS ARE DIFFERENT. FORECAST LEANS TOWARD THE SLOWER ECMWF FOR THE END OF NEXT WEEK. SHOULD SEE MAINLY DRY CONDITIONS THROUGH TUESDAY AS THE UPPER RIDGE BUILDS ACROSS THE REGION AND SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC RIDGES INTO THE SOUTHEASTERN STATES. THE NEXT CHANCE OF PRECIP ARRIVES MID-WEEK. MAX TEMPERATURES WILL BE AROUND 90 TUESDAY WITH UPPER 80S WEDNESDAY COOLING INTO THE UPPER 70S TO LOWER 80S THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE 60S THROUGH THURSDAY AND IN THE 50S FRIDAY. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... SOME MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONT WILL BE IN THE FORECAST AREA THIS AFTERNOON AND EVENING. THE MOISTURE COMBINED WITH A LITTLE CONVERGENCE INTO A WEAK LEE-SIDE TROUGH WILL LIKELY SUPPORT THUNDERSTORMS. HOWEVER...THE MOISTURE WILL REMAIN LIMITED AND THE FORCING WILL BE WEAK. EXPECT SCATTERED COVERAGE. THE CHANCE OF THUNDERSTORMS IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. LIGHT WIND...SOME LOW-LEVEL MOISTURE AND NOCTURNAL COOLING MAY HELP CAUSE FOG LATE TONIGHT. SOME OF THE NAM AND GFS MOS INDICATE MVFR OR IFR FOG WITH THE GREATER RESTRICTIONS AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. .EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED THROUGH WEDNESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
932 PM CDT SUN MAY 11 2014 .DISCUSSION... 930 PM CDT STORMS ACROSS THE FAR SOUTHERN FORECAST AREA HAVE SHOWN A CONSISTENT WEAKENING TREND IN THE PAST HOUR. STILL SOME CONVERGENCE ON THE OUTFLOW BOUNDARY WITH WARM/MOIST ADVECTION 850-925MB ADVECTION INTO THIS AREA. SO SOME REGENERATION OF STORMS MAY CONTINUE AS RADAR TRENDS HAVE INDICATED IN MCCLEAN COUNTY...ALTHOUGH THE REFLECTIVITY TREND IS GENERALLY DOWNWARDS. SO THE FLOODING THREAT IS GRADUALLY DIMINISHING. TEMPORARY SUPPRESSION AND MID-LEVEL DRYING BEHIND MCS SHOULD KEEP MUCH OF THE FORECAST AREA QUIET THROUGH 3 AM OR SO. WIDESPREAD CONVECTION ACROSS WESTERN IOWA SHOULD EVOLVE EAST NORTHEAST WITH POSSIBLE SCATTERED DEVELOPMENT AHEAD OF THIS ON THE LOW-LEVEL JET AND JUST INCREASING UPPER/MID-LEVEL FORCING. THIS IS MOST FAVORED IN NORTH CENTRAL ILLINOIS...INCLUDING TOWARD ROCKFORD. THIS WOULD HAVE A SMALL SEVERE WEATHER CHANCE. OVERALL BUILDING HEIGHTS SHOULD LIMIT A WELL-DEVELOPED MCS FROM THE WEST MOVING INTO THE FORECAST AREA. MTF && .PREV DISCUSSION... 300 PM CDT FORECAST CONCERNS ARE MAINLY ON THE IMMEDIATE SEVERE WEATHER CHANCES THROUGH EARLY/MID EVENING. ALSO FOCUS ON THE SEVERE WEATHER POTENTIAL ON MONDAY...PRIMARILY MONDAY LATE AFTERNOON INTO THE NIGHTTIME PERIOD. OVERNIGHT INTO MONDAY MORNING... STRONG UPPER JET WILL PROPAGATE AROUND THE UPPER TROUGH LATE TONIGHT INTO THE MORNING ON MONDAY AND WITH THAT LEAD TO FURTHER AMPLIFYING OF THE UPSTREAM RIDGE...INCLUDING BUILDING HEIGHTS ACROSS MUCH OF THE FORECAST AREA. MUCH OF THE FORCING FOR RAIN/STORMS IN THIS PERIOD WOULD BE FOCUSED TO THE WEST AND NORTH IN SUCH A PATTERN. THE STRONG LOW-LEVEL JET WILL AT LEAST IN PART BE OVER THE AREA...HOWEVER THE NOSE OF IT WILL BE POINTED FURTHER NORTH. CONVECTIVE CHANCES LOOK MINIMAL AND MAINLY THE NORTHWEST FORECAST AREA TOWARD ROCKFORD. CHANCES MAY BE INCREASED SOMEWHAT IF ANY ORGANIZED CONVECTION FROM THE CENTRAL PLAINS WERE TO PROPAGATE EASTWARD INTO NORTHERN IL...BUT THE GRADUALLY MORE MERIDIONAL FLOW AND ORIENTATION OF FORECAST CORFIDI VECTORS WOULD PUSH MUCH OF THE CONVECTION NORTH OF THE AREA. LOW TEMPS WILL BE BALMY WITH CONTINUED SOUTHERLY FLOW AND HIGH DEW POINT AIR...WITH SOME PLACES EXPERIENCING SOME WARMING OF TEMPS LATER THIS EVENING...ESPECIALLY THOSE IMPACTED BY EARLY EVE CONVECTION AND THOSE COMMUNITIES NEAR THE LAKE SHORE THAT HAD AFTERNOON/EVE COOLING. MONDAY AFTERNOON THROUGH TUESDAY... THE UPPER TROUGH WILL CONTINUE TO AMPLIFY AS THE UPPER JET TO ITS FRONT AND BACK INTENSITY. A WARM AND MUGGY DAY IS ANTICIPATED MONDAY. CONVECTIVE INHIBITION ON MONDAY AFTERNOON DOES LOOK TO BE OVERCOME BUT A FOCUS IS NOT OVERLY EVIDENT IN OUR FORECAST AREA. GRADUALLY MORE CONVERGENCE AND INCREASING DEEP LAYER MOISTURE AND UPWARD MOTION IS FORECAST TO MOVE EASTWARD ACROSS MAINLY NORTH CENTRAL ILLINOIS LATE IN THE DAY INTO EARLY EVE AND EASE ITS WAY EASTWARD THROUGH THE REMAINDER OF THE NIGHT. THIS LOOKS LIKE A PERIOD OF STORMS MOVING NORTHEAST WITHIN THE DEEP MOIST PLUME. THE SEVERE POTENTIAL WOULD SEEM MOST FAVORED WITH THE INITIAL CONVECTION IN THE LATE AFTERNOON/EVE AND THEN A GENERAL WANING LATER INTO THE NIGHT. LOCALLY HEAVY RAINFALL WILL BE PROBABLE IN SOME OF THESE STORMS AS THE PWATS ARE FORECAST TO BE AROUND 1.50 INCHES AND DEEP MOISTURE CONVERGENCE WILL BE ORIENTED PARALLEL TO THE UPPER FLOW. THIS PLUME WILL SHIFT EASTWARD THROUGH TUESDAY MORNING AND LIKELY POPS CERTAINLY SEEM JUSTIFIED TUESDAY MORNING. IF THE FRONT IS SLOW ENOUGH SOME AFTERNOON ENHANCEMENT OF A FEW STORMS COULD HAPPEN IN THE EAST...BUT THIS SEEMS MOST FAVORED EAST OF THE FORECAST AREA AT THIS TIME. THE COLD AIR ADVECTION WITH THE COLD FRONT...ALONG WITH POTENTIALLY SOME ANAFRONTAL SHOWERS...WILL LIKELY LEAD TO FALLING TEMPS IN SOME PLACES AT LEAST AT TIMES ON TUESDAY. WEDNESDAY AND BEYOND... LITTLE CHANGES MADE TO THIS PART OF THE FORECAST DUE TO ONGOING HIGHER IMPACT WEATHER. LARGE MODEL DIFFERENCES EXIST IN THE WED-THU TIME FRAME...WITH THE 12Z EC COMING IN SLOWER AND MORE AGGRESSIVE WITH A LOW RIDING UP THE BAROCLINIC ZONE TO OUR EAST. THIS PROVIDES WIDESPREAD SHOWERS WEDNESDAY AFTERNOON THROUGH EARLY THURSDAY AND PARTICULARY COOL TEMPS. WITH AN EC/GFS/GOING FORECAST BLEND THIS PROVIDES A FEW PERIODS OF CHANCE POPS. TEMPS TO LOOK TO BE BELOW NORMAL NO MATTER WHICH MODEL VERIFIES IN THE WED-FRI TIME FRAME. IF CONDITIONS CLEAR AND SURFACE RIDGING MOVES OVER...POSSIBLY THU NIGHT...THERE PROBABLY WILL BE A CONCERN FOR FROST. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * SHRA/TSRA THROUGH MID EVENING. * WIND DIRECTIONS THIS EVENING. * POSSIBLE MVFR CIGS MONDAY MORNING. * STRONG/GUSTY SOUTHERLY WINDS MONDAY. * POSSIBLE TSRA LATE MONDAY AFTERNOON/MONDAY EVENING. CMS //DISCUSSION...UPDATED 00Z... TSRA HAS CONTINUED TO CONSOLIDATE AND MOVE EAST. ADDITIONAL SHRA WITH AN OCCASIONAL LIGHTNING STRIKE WILL CONTINUE FOR THE NEXT HOUR OR TWO. THE BULK OF THIS ACTIVITY IS EXPECTED TO BE EAST OR SOUTHEAST OF THE CHICAGO AREA TERMINALS BY 02Z-03Z AND HAVE MAINTAINED SIMILAR TIMING/TRENDS FROM THE PREVIOUS FORECAST. ANOTHER LINE OF TSRA OVER THE PLAINS WILL NEED TO BE MONITORED AS IT MOVES EAST OVERNIGHT. CONFIDENCE IS LOW REGARDING HOW FAR EAST THIS WILL MOVE BEFORE DISSIPATING. SOME OF THE SHORT TERM GUIDANCE WOULD SUGGEST THAT THIS WILL MAKE IT INTO THE RFD AREA BY DAYBREAK. INCLUDED A VCSH MENTION THERE BUT FURTHER EAST...MAINTAINED DRY FORECAST AND TRENDS WILL NEED TO BE MONITORED THROUGH THE NIGHT. LOW CONFIDENCE CONTINUES FOR PRECIP CHANCES THROUGH SUNSET MONDAY. WHILE MUCH OF MONDAY LOOKS DRY...ITS POSSIBLE THAT ISOLATED TSRA MAY DEVELOP ACROSS PARTS OF NORTHERN IL...POSSIBLY REMAINING NORTH OF THE TERMINALS. WITH THE LOW LEVELS NOW SATURATED...AS LOW LEVEL MOISTURE INCREASES...THERE IS A POTENTIAL FOR LOW MVFR CIGS TO DEVELOP OVERNIGHT AND PERSIST INTO THE MID MORNING HOURS. CONFIDENCE IS NOT HIGH AND MAINTAINED SCATTERED MENTION FOR NOW. WINDS WILL SETTLE BACK TO SOUTHEAST AROUND 10KTS THIS EVENING THEN TURN MORE SOUTHERLY OVERNIGHT WITH THE POTENTIAL FOR SOME GUSTS INTO THE MID TEEN RANGE. WIND SPEEDS/GUSTS WILL THEN STEADILY INCREASE THROUGH THE MORNING WITH GUSTS INTO THE MID TO UPPER 20 KT RANGE FOR THE AFTERNOON. LOW LEVEL WINDS NOW APPEAR LOW ENOUGH OVERNIGHT INTO MONDAY MORNING THAT LOW LEVEL WIND SHEAR CRITERIA WILL NOT BE MET AND REMOVED IT FROM THIS FORECAST. CMS //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH FOR SHRA/TSRA EARLY THIS EVENING. * LOW FOR WIND DIRECTIONS THIS EVENING...MEDIUM FOR WINDS FOR THE REST OF THE PERIOD. * LOW FOR MVFR CIGS OVERNIGHT/MONDAY MORNING. * LOW FOR TSRA LATE MONDAY AFTERNOON/MONDAY NIGHT. CMS //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY IN THE MORNING. * WEDNESDAY...CHANCE OF SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY...DRY/VFR. && .MARINE... 242 PM...LOW PRESSURE OVER KANSAS WILL MOVE NORTHEAST TO LAKE SUPERIOR TUESDAY MORNING. AS IT DOES...A WARM FRONT EXTENDING EAST FROM THE LOW WILL MOVE NORTH ACROSS THE LAKE TONIGHT THROUGH MONDAY NIGHT...SHIFTING EASTERLY WINDS SOUTHERLY. LOW LEVEL MOISTURE WILL ALSO BE INCREASING AND AS IT SPREADS ACROSS THE COOLER LAKE...AREAS OF FOG ARE POSSIBLE AND SOME OF THE FOG MAY BECOME DENSE. CURRENT WIND SPEEDS ARE FAIRLY LIGHT IN THE 5-15 KT RANGE AND WILL INCREASE INTO THE 15-25KT RANGE AND REMAIN THERE UNTIL A COLD FRONT MOVES ACROSS THE LAKE TUESDAY MORNING. THERE IS A POTENTIAL FOR WINDS TO BE A BIT STRONGER ON MONDAY...ESPECIALLY WITH THE EASTERLY FLOW NORTH OF THE WARM FRONT ACROSS NORTHERN LAKE MICHIGAN. THERE REMAINS UNCERTAINTY REGARDING THE POTENTIAL FOR STRONG NORTHERLY WINDS WEDNESDAY NIGHT INTO THURSDAY AS LOW PRESSURE DEEPENS MOVING NORTH ACROSS THE GREAT LAKES REGION. THIS TIME PERIOD WILL NEED TO BE MONITORED FOR HIGHER NORTHERLY WIND SPEEDS. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 931 PM CDT Sun May 11 2014 .DISCUSSION... ISSUED 927 PM CDT Sun May 11 2014 The rest of WW #144 will be let go at 10 pm CDT. Most of the stronger storms have shifted off to our east with some lingering showers over north central McLean county. Large bow echo over western Iowa tracking east northeast at 45 to 50 mph. Latest HRRR model suggest what is left of the complex may get into western IL just before 12z. Will continue to keep low chance POPs across the north with the remainder of the area expecting to see dry conditions. Overall, the grids are in good shape. Will update the ZFP once our watch expires at 10 pm. Smith && .AVIATION... ISSUED 649 PM CDT Sun May 11 2014 VFR conditions expected across the central Illinois terminals through the 00Z TAF valid time. A warm front has lifted north of the area today, associated with a few showers/storms. However, now mainly dry conditions are anticipated until the trailing cold front associated with the same storm system pushes into the area Monday night. While this dry period should last across most of the area until after 00Z Tuesday, VFR low/mid cloud cigs will last for much of the next 24 hours. Gusty southerly winds will fall off this evening with the loss of diurnal heating/mixing. This, and an approaching low level jet, will allow LLWS to develop later tonight. The LLWS will end as deeper mixing and gustiness returns Monday morning. Bak && .PREV DISCUSSION... ISSUED 248 PM CDT Sun May 11 2014 Air mass destabilizing quickly across central and southeast Illinois early this afternoon. 18Z upper air sounding from our office showing CAPE of around 2600 J/kg with no convective inhibition, although shear values are not especially impressive. Latest SPC mesoanalysis indicates CAPE`s are over 3000 J/kg south of I-72, as dew points of 70 degrees have made it as far north as Taylorville. Warm front extends from southern Nebraska along the Iowa/Missouri border, but becomes more diffuse in northern Illinois where it is more of a dew point discontinuity. Thunderstorms have been percolating most of the day across the Ohio Valley, and a persistent, small MCS is advancing across Iowa. Some development has recently started as well across northeast Missouri south of the main MCS. Has been quiet in our area the last few hours, but latest radar returns are starting to show thunderstorms developing between Taylorville and St Louis. The primary forecast concern remains with the severe weather threat over the next 24 to 36 hours. SHORT TERM...Tonight through Tuesday: Latest runs of the HRRR have been persistent with the Iowa storms affecting more of the northern third of Illinois, with more scattered strong/severe storms affecting our area through about 7 pm. Shear parameters don`t really improve any in our area, so thinking that hail/wind threat will be the primary concerns here with the tornado threat closer to the warm front. After sunset, capping of the atmosphere will begin in the warm sector. Have maintained some 30-40% PoP`s after midnight northwest of the Illinois River, and slight chances as far east as I-55, with dry conditions across the southeast half of the forecast area. Similar convective parameters expected on Monday, with CAPE`s rising to 2500-3000 J/kg, although shear remains on the low side. Day2 slight risk basically along and northwest of the Illinois River, where the shear will be a bit higher as it is closer to the incoming cold front, and severe weather threat will mainly be mid afternoon to early evening. With the front slowing down a tad, will keep any PoP`s east of I-57 around 20% during the day, while likely PoP`s around 60% found during the afternoon along/west of the Illinois River. Have maintained the 60-70% PoP`s everywhere during the night as the front slowly moves through, and over the eastern CWA on Tuesday with some 80% values south of I-70 Tuesday. Severe weather threat on Tuesday appears minimal, and would be near the Indiana border if any did occur. LONG TERM...Wednesday through Sunday: A broad upper trough will be dominating much of the eastern half of the nation into the first part of the weekend, with cool conditions prevailing. The ECMWF has been persistent with a closed upper low forming by late Thursday over the Great Lakes, then lifting northward, while the GFS keeps a more progressive trough. Toward the end of the weekend, the trough will finally start to break down as an upper low digs southward across the Pacific Northwest, causing rising heights over the center of the nation. Most challenging area in this forecast period is with rain on Wednesday. The tail end of the NAM is trending toward the solution favored by the ECMWF and GEM for the last few days, with a surface low riding northeast along the base of the trough, although the NAM is much further west with it. The GFS has keep its surface features much weaker and further east. Have kept the likely PoP`s on Wednesday across the southeast third of the area, although the ECMWF/GEM solutions would likely require this to be expanded further northwest toward the I-55 corridor. Thursday and Friday, the rain will be much more scattered in nature, as weak troughs rotate around through the broad upper trough. Rain chances will diminish this weekend as the upper flow flattens. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
804 PM CDT SUN MAY 11 2014 .MESOSCALE DISCUSSION... 804 PM CDT THE TORNADO WARNED CELL ACROSS CENTRAL NEWTON AND JASPER COUNTIES IS FOR A RAPIDLY INTENSIFYING UPDRAFT WITH VERTICALLY CONSISTENT AND STRENGTHENING ROTATION. THIS STORM IS AT THE VERY SOUTHERN EDGE OF THE ONGOING CLUSTER/COMPLEX AND IS FEEDING ON 100-150 J/KG OF 0-3KM CAPE...AND A MODIFIED RAP SOUNDING DOES INDICATE LIFT FROM THE SURFACE ALONG WITH LOWERING LCLS FROM EARLIER ACTIVITY FURTHER WEST AND NORTH. THE 0-1KM SHEAR IS SLIGHTLY MARGINAL AT 15 KT BUT INCREASING WITH THE STRENGTHENING LOW-LEVEL JET. IN ADDITION...A FUNNEL CLOUD REPORT WAS RECEIVED FROM JUST NORTH OF BROOK INDIANA AT 757 PM WITH THIS STORM. MTF && .DISCUSSION... 300 PM CDT FORECAST CONCERNS ARE MAINLY ON THE IMMEDIATE SEVERE WEATHER CHANCES THROUGH EARLY/MID EVENING. ALSO FOCUS ON THE SEVERE WEATHER POTENTIAL ON MONDAY...PRIMARILY MONDAY LATE AFTERNOON INTO THE NIGHTTIME PERIOD. OVERNIGHT INTO MONDAY MORNING... STRONG UPPER JET WILL PROPAGATE AROUND THE UPPER TROUGH LATE TONIGHT INTO THE MORNING ON MONDAY AND WITH THAT LEAD TO FURTHER AMPLIFYING OF THE UPSTREAM RIDGE...INCLUDING BUILDING HEIGHTS ACROSS MUCH OF THE FORECAST AREA. MUCH OF THE FORCING FOR RAIN/STORMS IN THIS PERIOD WOULD BE FOCUSED TO THE WEST AND NORTH IN SUCH A PATTERN. THE STRONG LOW-LEVEL JET WILL AT LEAST IN PART BE OVER THE AREA...HOWEVER THE NOSE OF IT WILL BE POINTED FURTHER NORTH. CONVECTIVE CHANCES LOOK MINIMAL AND MAINLY THE NORTHWEST FORECAST AREA TOWARD ROCKFORD. CHANCES MAY BE INCREASED SOMEWHAT IF ANY ORGANIZED CONVECTION FROM THE CENTRAL PLAINS WERE TO PROPAGATE EASTWARD INTO NORTHERN IL...BUT THE GRADUALLY MORE MERIDIONAL FLOW AND ORIENTATION OF FORECAST CORFIDI VECTORS WOULD PUSH MUCH OF THE CONVECTION NORTH OF THE AREA. LOW TEMPS WILL BE BALMY WITH CONTINUED SOUTHERLY FLOW AND HIGH DEW POINT AIR...WITH SOME PLACES EXPERIENCING SOME WARMING OF TEMPS LATER THIS EVENING...ESPECIALLY THOSE IMPACTED BY EARLY EVE CONVECTION AND THOSE COMMUNITIES NEAR THE LAKE SHORE THAT HAD AFTERNOON/EVE COOLING. MONDAY AFTERNOON THROUGH TUESDAY... THE UPPER TROUGH WILL CONTINUE TO AMPLIFY AS THE UPPER JET TO ITS FRONT AND BACK INTENSITY. A WARM AND MUGGY DAY IS ANTICIPATED MONDAY. CONVECTIVE INHIBITION ON MONDAY AFTERNOON DOES LOOK TO BE OVERCOME BUT A FOCUS IS NOT OVERLY EVIDENT IN OUR FORECAST AREA. GRADUALLY MORE CONVERGENCE AND INCREASING DEEP LAYER MOISTURE AND UPWARD MOTION IS FORECAST TO MOVE EASTWARD ACROSS MAINLY NORTH CENTRAL ILLINOIS LATE IN THE DAY INTO EARLY EVE AND EASE ITS WAY EASTWARD THROUGH THE REMAINDER OF THE NIGHT. THIS LOOKS LIKE A PERIOD OF STORMS MOVING NORTHEAST WITHIN THE DEEP MOIST PLUME. THE SEVERE POTENTIAL WOULD SEEM MOST FAVORED WITH THE INITIAL CONVECTION IN THE LATE AFTERNOON/EVE AND THEN A GENERAL WANING LATER INTO THE NIGHT. LOCALLY HEAVY RAINFALL WILL BE PROBABLE IN SOME OF THESE STORMS AS THE PWATS ARE FORECAST TO BE AROUND 1.50 INCHES AND DEEP MOISTURE CONVERGENCE WILL BE ORIENTED PARALLEL TO THE UPPER FLOW. THIS PLUME WILL SHIFT EASTWARD THROUGH TUESDAY MORNING AND LIKELY POPS CERTAINLY SEEM JUSTIFIED TUESDAY MORNING. IF THE FRONT IS SLOW ENOUGH SOME AFTERNOON ENHANCEMENT OF A FEW STORMS COULD HAPPEN IN THE EAST...BUT THIS SEEMS MOST FAVORED EAST OF THE FORECAST AREA AT THIS TIME. THE COLD AIR ADVECTION WITH THE COLD FRONT...ALONG WITH POTENTIALLY SOME ANAFRONTAL SHOWERS...WILL LIKELY LEAD TO FALLING TEMPS IN SOME PLACES AT LEAST AT TIMES ON TUESDAY. WEDNESDAY AND BEYOND... LITTLE CHANGES MADE TO THIS PART OF THE FORECAST DUE TO ONGOING HIGHER IMPACT WEATHER. LARGE MODEL DIFFERENCES EXIST IN THE WED-THU TIME FRAME...WITH THE 12Z EC COMING IN SLOWER AND MORE AGGRESSIVE WITH A LOW RIDING UP THE BAROCLINIC ZONE TO OUR EAST. THIS PROVIDES WIDESPREAD SHOWERS WEDNESDAY AFTERNOON THROUGH EARLY THURSDAY AND PARTICULARY COOL TEMPS. WITH AN EC/GFS/GOING FORECAST BLEND THIS PROVIDES A FEW PERIODS OF CHANCE POPS. TEMPS TO LOOK TO BE BELOW NORMAL NO MATTER WHICH MODEL VERIFIES IN THE WED-FRI TIME FRAME. IF CONDITIONS CLEAR AND SURFACE RIDGING MOVES OVER...POSSIBLY THU NIGHT...THERE PROBABLY WILL BE A CONCERN FOR FROST. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * SHRA/TSRA THROUGH MID EVENING. * WIND DIRECTIONS THIS EVENING. * POSSIBLE MVFR CIGS MONDAY MORNING. * STRONG/GUSTY SOUTHERLY WINDS MONDAY. * POSSIBLE TSRA LATE MONDAY AFTERNOON/MONDAY EVENING. CMS //DISCUSSION...UPDATED 00Z... TSRA HAS CONTINUED TO CONSOLIDATE AND MOVE EAST. ADDITIONAL SHRA WITH AN OCCASIONAL LIGHTNING STRIKE WILL CONTINUE FOR THE NEXT HOUR OR TWO. THE BULK OF THIS ACTIVITY IS EXPECTED TO BE EAST OR SOUTHEAST OF THE CHICAGO AREA TERMINALS BY 02Z-03Z AND HAVE MAINTAINED SIMILAR TIMING/TRENDS FROM THE PREVIOUS FORECAST. ANOTHER LINE OF TSRA OVER THE PLAINS WILL NEED TO BE MONITORED AS IT MOVES EAST OVERNIGHT. CONFIDENCE IS LOW REGARDING HOW FAR EAST THIS WILL MOVE BEFORE DISSIPATING. SOME OF THE SHORT TERM GUIDANCE WOULD SUGGEST THAT THIS WILL MAKE IT INTO THE RFD AREA BY DAYBREAK. INCLUDED A VCSH MENTION THERE BUT FURTHER EAST...MAINTAINED DRY FORECAST AND TRENDS WILL NEED TO BE MONITORED THROUGH THE NIGHT. LOW CONFIDENCE CONTINUES FOR PRECIP CHANCES THROUGH SUNSET MONDAY. WHILE MUCH OF MONDAY LOOKS DRY...ITS POSSIBLE THAT ISOLATED TSRA MAY DEVELOP ACROSS PARTS OF NORTHERN IL...POSSIBLY REMAINING NORTH OF THE TERMINALS. WITH THE LOW LEVELS NOW SATURATED...AS LOW LEVEL MOISTURE INCREASES...THERE IS A POTENTIAL FOR LOW MVFR CIGS TO DEVELOP OVERNIGHT AND PERSIST INTO THE MID MORNING HOURS. CONFIDENCE IS NOT HIGH AND MAINTAINED SCATTERED MENTION FOR NOW. WINDS WILL SETTLE BACK TO SOUTHEAST AROUND 10KTS THIS EVENING THEN TURN MORE SOUTHERLY OVERNIGHT WITH THE POTENTIAL FOR SOME GUSTS INTO THE MID TEEN RANGE. WIND SPEEDS/GUSTS WILL THEN STEADILY INCREASE THROUGH THE MORNING WITH GUSTS INTO THE MID TO UPPER 20 KT RANGE FOR THE AFTERNOON. LOW LEVEL WINDS NOW APPEAR LOW ENOUGH OVERNIGHT INTO MONDAY MORNING THAT LOW LEVEL WIND SHEAR CRITERIA WILL NOT BE MET AND REMOVED IT FROM THIS FORECAST. CMS //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH FOR SHRA/TSRA EARLY THIS EVENING. * LOW FOR WIND DIRECTIONS THIS EVENING...MEDIUM FOR WINDS FOR THE REST OF THE PERIOD. * LOW FOR MVFR CIGS OVERNIGHT/MONDAY MORNING. * LOW FOR TSRA LATE MONDAY AFTERNOON/MONDAY NIGHT. CMS //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY IN THE MORNING. * WEDNESDAY...CHANCE OF SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY...DRY/VFR. && .MARINE... 242 PM...LOW PRESSURE OVER KANSAS WILL MOVE NORTHEAST TO LAKE SUPERIOR TUESDAY MORNING. AS IT DOES...A WARM FRONT EXTENDING EAST FROM THE LOW WILL MOVE NORTH ACROSS THE LAKE TONIGHT THROUGH MONDAY NIGHT...SHIFTING EASTERLY WINDS SOUTHERLY. LOW LEVEL MOISTURE WILL ALSO BE INCREASING AND AS IT SPREADS ACROSS THE COOLER LAKE...AREAS OF FOG ARE POSSIBLE AND SOME OF THE FOG MAY BECOME DENSE. CURRENT WIND SPEEDS ARE FAIRLY LIGHT IN THE 5-15 KT RANGE AND WILL INCREASE INTO THE 15-25KT RANGE AND REMAIN THERE UNTIL A COLD FRONT MOVES ACROSS THE LAKE TUESDAY MORNING. THERE IS A POTENTIAL FOR WINDS TO BE A BIT STRONGER ON MONDAY...ESPECIALLY WITH THE EASTERLY FLOW NORTH OF THE WARM FRONT ACROSS NORTHERN LAKE MICHIGAN. THERE REMAINS UNCERTAINTY REGARDING THE POTENTIAL FOR STRONG NORTHERLY WINDS WEDNESDAY NIGHT INTO THURSDAY AS LOW PRESSURE DEEPENS MOVING NORTH ACROSS THE GREAT LAKES REGION. THIS TIME PERIOD WILL NEED TO BE MONITORED FOR HIGHER NORTHERLY WIND SPEEDS. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
711 PM CDT SUN MAY 11 2014 .MESOSCALE DISCUSSION... 550 PM CDT THE SEVERE WEATHER THREAT CONTINUES ACROSS THE AREA. A LOCAL EXPANSION OF THE SEVERE THUNDERSTORM WATCH HAS BEEN DONE TO INCLUDE THE FAR SOUTHEAST COUNTY WARNING AREA. STORMS SOME OF WHICH ARE SEVERE CONTINUE TO PROPAGATE EAST FEEDING ON UNCAPPED AND VERY UNSTABLE AIR...WITH MLCAPE VALUES OF 2000-3000 J/KG ACROSS THE AREA. THIS AREA NORTH OF THE WARM FRONT HAD DEVELOPED FAIRLY STEEP LOW-LEVEL LAPSE RATES PER AMDAR SOUNDINGS AND THUS INCREASED SOME OF THE WIND POTENTIAL. RADAR HAS ALSO INDICATED SOME OUTFLOWS QUICKLY RACING OUT FROM THESE STORMS AS EVIDENCE TO THIS. WIND AND HAIL THREATS CONTINUE WITH THE STRONGEST CORES...INCLUDING ONE APPROACHING DOWNTOWN CHICAGO AS OF 550 PM. AN ARC OF SEVERE STORMS FROM NEAR KEWANEE EAST SOUTHEAST TOWARD WATSEKA IS LIFTING SLOWLY NORTHEAST. THIS IS JUST AHEAD OF REMNANT MCV. AS MID-LEVEL WINDS PICK UP FROM THE WEST...OVERALL SHEAR/INSTABILITY SPECTRUM WILL CONTINUE TO FAVOR SEVERE POTENTIAL WITH THESE AS WELL...WITH MODE LIKELY CONTINUING TO SHIFT TO LESS DISCRETE AS MESOSCALE COLD POOLS INTERACT. IN ADDITION...A HEAVY RAIN AND POSSIBLE FLOODING THREAT MAY TEMPORARILY EVOLVE EARLY THIS EVE NEAR THE I-80 CORRIDOR AS THIS AFOREMENTIONED ARC OF STORMS BECOMES MORE WEST-TO-EAST ORIENTED AHEAD OF MCV. COULD BE A 1-3 HOUR EPISODE OF MODERATE TO HEAVY RAINFALL RATES. THIS IS BEING MONITORED CLOSELY. THE SECONDARY WARM FRONT CONTINUES TO REMAIN PRIMARILY TO THE SOUTH OF THE AREA AND SOMEWHAT DIFFUSE. WHILE PRESSURE FALLS AND HIGHER DEW POINT AIR IS EVOLVING INTO THE SOUTHERN FORECAST AREA...THE DEGREE OF BACKING WINDS HAS NOT BEEN THAT NOTEWORTHY...AND THUS THE TORNADO THREAT IS DIMINISHING. STILL A NONZERO CHANCE THOUGH...MAINLY SOUTH OF INTERSTATE 80 AND WEST OF ILLINOIS HIGHWAY 47. MTF && .DISCUSSION... 300 PM CDT FORECAST CONCERNS ARE MAINLY ON THE IMMEDIATE SEVERE WEATHER CHANCES THROUGH EARLY/MID EVENING. ALSO FOCUS ON THE SEVERE WEATHER POTENTIAL ON MONDAY...PRIMARILY MONDAY LATE AFTERNOON INTO THE NIGHTTIME PERIOD. OVERNIGHT INTO MONDAY MORNING... STRONG UPPER JET WILL PROPAGATE AROUND THE UPPER TROUGH LATE TONIGHT INTO THE MORNING ON MONDAY AND WITH THAT LEAD TO FURTHER AMPLIFYING OF THE UPSTREAM RIDGE...INCLUDING BUILDING HEIGHTS ACROSS MUCH OF THE FORECAST AREA. MUCH OF THE FORCING FOR RAIN/STORMS IN THIS PERIOD WOULD BE FOCUSED TO THE WEST AND NORTH IN SUCH A PATTERN. THE STRONG LOW-LEVEL JET WILL AT LEAST IN PART BE OVER THE AREA...HOWEVER THE NOSE OF IT WILL BE POINTED FURTHER NORTH. CONVECTIVE CHANCES LOOK MINIMAL AND MAINLY THE NORTHWEST FORECAST AREA TOWARD ROCKFORD. CHANCES MAY BE INCREASED SOMEWHAT IF ANY ORGANIZED CONVECTION FROM THE CENTRAL PLAINS WERE TO PROPAGATE EASTWARD INTO NORTHERN IL...BUT THE GRADUALLY MORE MERIDIONAL FLOW AND ORIENTATION OF FORECAST CORFIDI VECTORS WOULD PUSH MUCH OF THE CONVECTION NORTH OF THE AREA. LOW TEMPS WILL BE BALMY WITH CONTINUED SOUTHERLY FLOW AND HIGH DEW POINT AIR...WITH SOME PLACES EXPERIENCING SOME WARMING OF TEMPS LATER THIS EVENING...ESPECIALLY THOSE IMPACTED BY EARLY EVE CONVECTION AND THOSE COMMUNITIES NEAR THE LAKE SHORE THAT HAD AFTERNOON/EVE COOLING. MONDAY AFTERNOON THROUGH TUESDAY... THE UPPER TROUGH WILL CONTINUE TO AMPLIFY AS THE UPPER JET TO ITS FRONT AND BACK INTENSITY. A WARM AND MUGGY DAY IS ANTICIPATED MONDAY. CONVECTIVE INHIBITION ON MONDAY AFTERNOON DOES LOOK TO BE OVERCOME BUT A FOCUS IS NOT OVERLY EVIDENT IN OUR FORECAST AREA. GRADUALLY MORE CONVERGENCE AND INCREASING DEEP LAYER MOISTURE AND UPWARD MOTION IS FORECAST TO MOVE EASTWARD ACROSS MAINLY NORTH CENTRAL ILLINOIS LATE IN THE DAY INTO EARLY EVE AND EASE ITS WAY EASTWARD THROUGH THE REMAINDER OF THE NIGHT. THIS LOOKS LIKE A PERIOD OF STORMS MOVING NORTHEAST WITHIN THE DEEP MOIST PLUME. THE SEVERE POTENTIAL WOULD SEEM MOST FAVORED WITH THE INITIAL CONVECTION IN THE LATE AFTERNOON/EVE AND THEN A GENERAL WANING LATER INTO THE NIGHT. LOCALLY HEAVY RAINFALL WILL BE PROBABLE IN SOME OF THESE STORMS AS THE PWATS ARE FORECAST TO BE AROUND 1.50 INCHES AND DEEP MOISTURE CONVERGENCE WILL BE ORIENTED PARALLEL TO THE UPPER FLOW. THIS PLUME WILL SHIFT EASTWARD THROUGH TUESDAY MORNING AND LIKELY POPS CERTAINLY SEEM JUSTIFIED TUESDAY MORNING. IF THE FRONT IS SLOW ENOUGH SOME AFTERNOON ENHANCEMENT OF A FEW STORMS COULD HAPPEN IN THE EAST...BUT THIS SEEMS MOST FAVORED EAST OF THE FORECAST AREA AT THIS TIME. THE COLD AIR ADVECTION WITH THE COLD FRONT...ALONG WITH POTENTIALLY SOME ANAFRONTAL SHOWERS...WILL LIKELY LEAD TO FALLING TEMPS IN SOME PLACES AT LEAST AT TIMES ON TUESDAY. WEDNESDAY AND BEYOND... LITTLE CHANGES MADE TO THIS PART OF THE FORECAST DUE TO ONGOING HIGHER IMPACT WEATHER. LARGE MODEL DIFFERENCES EXIST IN THE WED-THU TIME FRAME...WITH THE 12Z EC COMING IN SLOWER AND MORE AGGRESSIVE WITH A LOW RIDING UP THE BAROCLINIC ZONE TO OUR EAST. THIS PROVIDES WIDESPREAD SHOWERS WEDNESDAY AFTERNOON THROUGH EARLY THURSDAY AND PARTICULARY COOL TEMPS. WITH AN EC/GFS/GOING FORECAST BLEND THIS PROVIDES A FEW PERIODS OF CHANCE POPS. TEMPS TO LOOK TO BE BELOW NORMAL NO MATTER WHICH MODEL VERIFIES IN THE WED-FRI TIME FRAME. IF CONDITIONS CLEAR AND SURFACE RIDGING MOVES OVER...POSSIBLY THU NIGHT...THERE PROBABLY WILL BE A CONCERN FOR FROST. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * SHRA/TSRA THROUGH MID EVENING. * WIND DIRECTIONS THIS EVENING. * POSSIBLE MVFR CIGS MONDAY MORNING. * STRONG/GUSTY SOUTHERLY WINDS MONDAY. * POSSIBLE TSRA LATE MONDAY AFTERNOON/MONDAY EVENING. CMS //DISCUSSION...UPDATED 00Z... TSRA HAS CONTINUED TO CONSOLIDATE AND MOVE EAST. ADDITIONAL SHRA WITH AN OCCASIONAL LIGHTNING STRIKE WILL CONTINUE FOR THE NEXT HOUR OR TWO. THE BULK OF THIS ACTIVITY IS EXPECTED TO BE EAST OR SOUTHEAST OF THE CHICAGO AREA TERMINALS BY 02Z-03Z AND HAVE MAINTAINED SIMILAR TIMING/TRENDS FROM THE PREVIOUS FORECAST. ANOTHER LINE OF TSRA OVER THE PLAINS WILL NEED TO BE MONITORED AS IT MOVES EAST OVERNIGHT. CONFIDENCE IS LOW REGARDING HOW FAR EAST THIS WILL MOVE BEFORE DISSIPATING. SOME OF THE SHORT TERM GUIDANCE WOULD SUGGEST THAT THIS WILL MAKE IT INTO THE RFD AREA BY DAYBREAK. INCLUDED A VCSH MENTION THERE BUT FURTHER EAST...MAINTAINED DRY FORECAST AND TRENDS WILL NEED TO BE MONITORED THROUGH THE NIGHT. LOW CONFIDENCE CONTINUES FOR PRECIP CHANCES THROUGH SUNSET MONDAY. WHILE MUCH OF MONDAY LOOKS DRY...ITS POSSIBLE THAT ISOLATED TSRA MAY DEVELOP ACROSS PARTS OF NORTHERN IL...POSSIBLY REMAINING NORTH OF THE TERMINALS. WITH THE LOW LEVELS NOW SATURATED...AS LOW LEVEL MOISTURE INCREASES...THERE IS A POTENTIAL FOR LOW MVFR CIGS TO DEVELOP OVERNIGHT AND PERSIST INTO THE MID MORNING HOURS. CONFIDENCE IS NOT HIGH AND MAINTAINED SCATTERED MENTION FOR NOW. WINDS WILL SETTLE BACK TO SOUTHEAST AROUND 10KTS THIS EVENING THEN TURN MORE SOUTHERLY OVERNIGHT WITH THE POTENTIAL FOR SOME GUSTS INTO THE MID TEEN RANGE. WIND SPEEDS/GUSTS WILL THEN STEADILY INCREASE THROUGH THE MORNING WITH GUSTS INTO THE MID TO UPPER 20 KT RANGE FOR THE AFTERNOON. LOW LEVEL WINDS NOW APPEAR LOW ENOUGH OVERNIGHT INTO MONDAY MORNING THAT LOW LEVEL WIND SHEAR CRITERIA WILL NOT BE MET AND REMOVED IT FROM THIS FORECAST. CMS //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH FOR SHRA/TSRA EARLY THIS EVENING. * LOW FOR WIND DIRECTIONS THIS EVENING...MEDIUM FOR WINDS FOR THE REST OF THE PERIOD. * LOW FOR MVFR CIGS OVERNIGHT/MONDAY MORNING. * LOW FOR TSRA LATE MONDAY AFTERNOON/MONDAY NIGHT. CMS //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY IN THE MORNING. * WEDNESDAY...CHANCE OF SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY...DRY/VFR. && .MARINE... 242 PM...LOW PRESSURE OVER KANSAS WILL MOVE NORTHEAST TO LAKE SUPERIOR TUESDAY MORNING. AS IT DOES...A WARM FRONT EXTENDING EAST FROM THE LOW WILL MOVE NORTH ACROSS THE LAKE TONIGHT THROUGH MONDAY NIGHT...SHIFTING EASTERLY WINDS SOUTHERLY. LOW LEVEL MOISTURE WILL ALSO BE INCREASING AND AS IT SPREADS ACROSS THE COOLER LAKE...AREAS OF FOG ARE POSSIBLE AND SOME OF THE FOG MAY BECOME DENSE. CURRENT WIND SPEEDS ARE FAIRLY LIGHT IN THE 5-15 KT RANGE AND WILL INCREASE INTO THE 15-25KT RANGE AND REMAIN THERE UNTIL A COLD FRONT MOVES ACROSS THE LAKE TUESDAY MORNING. THERE IS A POTENTIAL FOR WINDS TO BE A BIT STRONGER ON MONDAY...ESPECIALLY WITH THE EASTERLY FLOW NORTH OF THE WARM FRONT ACROSS NORTHERN LAKE MICHIGAN. THERE REMAINS UNCERTAINTY REGARDING THE POTENTIAL FOR STRONG NORTHERLY WINDS WEDNESDAY NIGHT INTO THURSDAY AS LOW PRESSURE DEEPENS MOVING NORTH ACROSS THE GREAT LAKES REGION. THIS TIME PERIOD WILL NEED TO BE MONITORED FOR HIGHER NORTHERLY WIND SPEEDS. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 649 PM CDT Sun May 11 2014 .DISCUSSION... ISSUED 248 PM CDT Sun May 11 2014 Air mass destabilizing quickly across central and southeast Illinois early this afternoon. 18Z upper air sounding from our office showing CAPE of around 2600 J/kg with no convective inhibition, although shear values are not especially impressive. Latest SPC mesoanalysis indicates CAPE`s are over 3000 J/kg south of I-72, as dew points of 70 degrees have made it as far north as Taylorville. Warm front extends from southern Nebraska along the Iowa/Missouri border, but becomes more diffuse in northern Illinois where it is more of a dew point discontinuity. Thunderstorms have been percolating most of the day across the Ohio Valley, and a persistent, small MCS is advancing across Iowa. Some development has recently started as well across northeast Missouri south of the main MCS. Has been quiet in our area the last few hours, but latest radar returns are starting to show thunderstorms developing between Taylorville and St Louis. The primary forecast concern remains with the severe weather threat over the next 24 to 36 hours. SHORT TERM...Tonight through Tuesday: Latest runs of the HRRR have been persistent with the Iowa storms affecting more of the northern third of Illinois, with more scattered strong/severe storms affecting our area through about 7 pm. Shear parameters don`t really improve any in our area, so thinking that hail/wind threat will be the primary concerns here with the tornado threat closer to the warm front. After sunset, capping of the atmosphere will begin in the warm sector. Have maintained some 30-40% PoP`s after midnight northwest of the Illinois River, and slight chances as far east as I-55, with dry conditions across the southeast half of the forecast area. Similar convective parameters expected on Monday, with CAPE`s rising to 2500-3000 J/kg, although shear remains on the low side. Day2 slight risk basically along and northwest of the Illinois River, where the shear will be a bit higher as it is closer to the incoming cold front, and severe weather threat will mainly be mid afternoon to early evening. With the front slowing down a tad, will keep any PoP`s east of I-57 around 20% during the day, while likely PoP`s around 60% found during the afternoon along/west of the Illinois River. Have maintained the 60-70% PoP`s everywhere during the night as the front slowly moves through, and over the eastern CWA on Tuesday with some 80% values south of I-70 Tuesday. Severe weather threat on Tuesday appears minimal, and would be near the Indiana border if any did occur. LONG TERM...Wednesday through Sunday: A broad upper trough will be dominating much of the eastern half of the nation into the first part of the weekend, with cool conditions prevailing. The ECMWF has been persistent with a closed upper low forming by late Thursday over the Great Lakes, then lifting northward, while the GFS keeps a more progressive trough. Toward the end of the weekend, the trough will finally start to break down as an upper low digs southward across the Pacific Northwest, causing rising heights over the center of the nation. Most challenging area in this forecast period is with rain on Wednesday. The tail end of the NAM is trending toward the solution favored by the ECMWF and GEM for the last few days, with a surface low riding northeast along the base of the trough, although the NAM is much further west with it. The GFS has keep its surface features much weaker and further east. Have kept the likely PoP`s on Wednesday across the southeast third of the area, although the ECMWF/GEM solutions would likely require this to be expanded further northwest toward the I-55 corridor. Thursday and Friday, the rain will be much more scattered in nature, as weak troughs rotate around through the broad upper trough. Rain chances will diminish this weekend as the upper flow flattens. Geelhart && .AVIATION... ISSUED 649 PM CDT Sun May 11 2014 VFR conditions expected across the central Illinois terminals through the 00Z TAF valid time. A warm front has lifted north of the area today, associated with a few showers/storms. However, now mainly dry conditions are anticipated until the trailing cold front associated with the same storm system pushes into the area Monday night. While this dry period should last across most of the area until after 00Z Tuesday, VFR low/mid cloud cigs will last for much of the next 24 hours. Gusty southerly winds will fall off this evening with the loss of diurnal heating/mixing. This, and an approaching low level jet, will allow LLWS to develop later tonight. The LLWS will end as deeper mixing and gustiness returns Monday morning. Bak && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
100 PM CDT SAT MAY 10 2014 .DISCUSSION... 252 AM CDT PRIMARY FORECAST CHALLENGE THIS MORNING REMAINS THE CONVECTIVE POTENTIAL STARTING TONIGHT AND CONTINUING AT TIMES THROUGH MONDAY NIGHT. SECONDARY CONCERNS INCLUDE TEMPERATURES SUNDAY INTO MONDAY AND THEN PRECIP CHANCES NEXT WEEK. HIGH PRESSURE OVER THE REGION TODAY SHOULD RESULT IN A PRETTY NICE DAY OVERALL. SLUG OF HIGH CLOUDINESS OVER MISSOURI IS ASSOCIATED WITH A SHORTWAVE ALOFT...MUCH MORE DEFINED AT 250MB THAN AT 500MB WITH VERY LITTLE REFLECTION AT 700MB. DRY LOW LEVELS AND ABSENCE OF FORCING SHOULD KEEP THIS ONLY A HIGH CLOUD PRODUCER AND MAINLY THIS MORNING. LIGHT WIND REGIME SHOULD ALLOW LAKE BREEZE TO FORM BY EARLY AFTERNOON WITH FALLING TEMPS NEAR THE LAKE THIS AFTERNOON...BUT FAIRLY MILD CONDITIONS AWAY FROM THE LAKE. TONIGHT LOW LEVEL JET SHOULD RESULT IN STRENGTHENING LOW LEVEL THETA-E ADVECTION AND LIKELY THE DEVELOPING OF SHOWERS AND THUNDERSTORMS OVER MISSOURI THIS EVENING. THIS ACTIVITY IS EXPECTED TO PUSH EAST INTO ILLINOIS LATE TONIGHT...HOWEVER GUIDANCE IS INCREASINGLY SUGGESTING THAT THE STRONGEST MOISTURE CONVERGENCE WILL REMAIN FARTHER SOUTH ACROSS CENTRAL ILLINOIS WITH FAR LESSER SUPPORT FROM PRECIP FARTHER NORTH. HAVE DECREASED POPS CONSIDERABLY OVER NORTHERN 2/3RD OF CWA...MAINTAINING CHANCE POPS MOSTLY FOR CONTINUITY SAKE AS IT LOOKS MORE AND MORE LIKELY THAT IT COULD STAY DRY ALTOGETHER NORTH OF I-80. FAR SOUTHERN CWA STANDS A BETTER CHANCE OF SEEING SOME OF THIS CONVECTION AND HAVE MAINTAINED HIGHER POPS THERE. SUNDAY SHOULD SEE DEVELOPING SOUTHERLY FLOW AS CYCLOGENESIS TAKES PLACE OVER THE PLAINS WITH STRENGTHENING WARM AND MOIST ADVECTION INTO THE AREA. DOES APPEAR AS THOUGH A SOMEWHAT ILL DEFINED WARM FRONT WILL DEVELOP AND LIFT NORTH ACROSS THE CWA SUNDAY BUT OTHERWISE SYNOPTIC SCALE FORCING LOOKS SOMEWHAT NEBULOUS...PARTICULARLY IN LIGHT IN STRONG HEIGHT RISES DOWNSTREAM OF THE AMPLIFYING TROUGH TO OUR WEST. CERTAINLY PLAUSIBLE THAT REMNANT MCV FROM TODAY`S CONVECTION OVER THE PLAINS OR FORCING ALONG THE WEAK WARM FRONT COULD BE ENOUGH TO KICK OF THUNDERSTORMS SUNDAY AFTERNOON...BUT OVERALL SYNOPTIC PATTERN WOULD ARGUE FOR LARGELY A RAIN-FREE DAY ACROSS THE CWA AND HAVE ATTEMPTED TO SCALE BACK POPS SOME. WORTH NOTING HOWEVER...THAT MODERATE INSTABILITY SHOULD DEVELOP WITH THE INCREASINGLY WARM/HUMID AIRMASS AND WITH STILL RESPECTABLE VALUES OF DEEP LAYER SHEAR THREAT DOES EXISTS FOR ANY CONVECTION THAT DOES DEVELOP SUNDAY AFTERNOON TO BE SEVERE. NOT TO MENTION THAT ILLINOIS WARM FRONTS SEEM TO LIKE TO PRODUCE "SURPRISES" THIS TIME OF YEAR. SOUTHERLY WINDS ON SUNDAY LOOK LIGHT ENOUGH FOR AT LEAST AN ILLINOIS SHORE LAKE BREEZE TO DEVELOP IN THE AFTERNOON...PARTICULARLY IF WARM FRONT BECOMES BETTER DEFINED AND WINDS MORE BACKED AHEAD OF IT. ASSUMING THIS SCENARIO PANS OUT DID KEEP LAKE COOLING IN THE GRIDS SUNDAY WITH FAIRLY WARM TEMPERATURES EXPECTED ELSEWHERE. BY SUNDAY NIGHT THE MAJORITY OF GUIDANCE AGREES THAT THE WARM FRONT WILL BECOME BETTER DEFINED TO OUR NORTH OVER WISCONSIN WITH FOCUS FOR POTENTIALLY SIGNIFICANT CONVECTIVE EVENT NORTH OF THE BORDER WITH OUR CWA JUST UNSEASONABLY WARM AND STEAMY WITH LOWS STRUGGLING TO DIP BELOW 70 DEGREES AS DEWPOINTS CLIMB WELL INTO THE 60S AND MODERATELY STRONG WINDS THROUGH THE NIGHT. GFS IS THE ODD MAN OUT KEEPING WARM FRONT AND SIGNIFICANT CONVECTION FARTHER SOUTH INTO OUR CWA. HAVE TRENDED POPS DOWN SUNDAY NIGHT...ESPECIALLY SOUTHERN CWA...BUT RELUCTANT TO GO TOO LOW GIVEN GFS SOLUTION AND POSSIBILITY THAT EVEN IF OTHER MODELS VERIFY OUTFLOW COULD PUSH SOUTH AND ALLOW CONVECTION TO PROPAGATE INTO OUR FAR NORTHERN CWA. UNUSUALLY HIGH PWATS AND SLOW MOVING NATURE OF WARM FRONT RAISE CONCERNS FOR HEAVY RAINFALL AND FLASH FLOODING...THOUGH THANKFULLY THAT APPEARS TO BE MORE OF A THREAT NORTH OF THE STATE LINE IN WISCONSIN. SUNDAY AFTERNOON`S LIKELY SEVERE CONVECTION OVER THE EASTERN PLAINS WILL PROBABLY SPILL A FAIR AMOUNT OF DEBRIS CLOUDINESS AND POSSIBLY SOME SHOWERS INTO THE AREA EARLY MONDAY...BUT AS THIS CONVECTION MOVES AWAY FROM BETTER UPPER SUPPORT AND INTO MORE CAPPED ENVIRONMENT TOWARD THE MS VALLEY WOULD EXPECT IT TO WEAKEN OR DISSIPATE ALTOGETHER. STRONG SOUTHERLY WINDS AND 925MB TEMPS PROGGED TO GET ABOVE 20C MONDAY COULD EASILY RESULT IN HIGHS IN THE UPPER 80S OVER MUCH OF THE CWA...THOUGH UNCERTAINTIES REGARDING EXTENT OF DEBRIS FROM SUNDAY`S PLAINS CONVECTION AND LOWER GUIDANCE VALUES HAVE PROMPTED ME TO BE MORE RESTRAINED IN MY BUMPING UP OVER TEMPS MONDAY. LOOKS LIKE STRONG TO SEVERE THUNDERSTORMS WILL DEVELOP TO OUR WEST MONDAY AFTERNOON WITH STORMS MOVING INTO OUR AREA MONDAY NIGHT IN ADVANCE OF APPROACHING STRONG COLD FRONT. GUIDANCE HAS CONTINUED TO KEEP THE STRONGER WINDS ALOFT BEHIND THE COLD FRONT RESULTING IN MORE MARGINAL SHEAR VALUES IN THE WARM SECTOR MONDAY. CERTAINLY LOOKS TO BE ENOUGH SHEAR FOR AN ORGANIZED MULTIPLE EVENT TO DEVELOP...BUT SOMEWHAT MARGINAL FOR A SUBSTANTIAL SEVERE THREAT LOCALLY...ESPECIALLY WITH TIMING OF STORMS ARRIVING AFTER DARK MONDAY NIGHT. THE GFS IS REALLY AGGRESSIVE IN DEVELOPING POST FRONTAL PRECIPITATION TUESDAY WITH OTHER GUIDANCE LESS GUNG-HO. OPTED TO HANG ONTO CHANCE POPS TUESDAY MORNING AS A NOD TO THE GFS BUT WOULDN`T BE SURPRISED IF MOST AREAS END UP DRY ALTOGETHER TUESDAY. PRETTY BIG UNCERTAINTIES LINGER WEDNESDAY THROUGH FRIDAY IN THE DETAILS OF ANY PRECIP CHANCES...THOUGH IT LOOKS LIKE THE MAJORITY OF THE TIME FRAME WILL BE DRY DESPITE THE NEED TO MAINTAIN LOW CHANCES POPS THROUGH THE PERIOD. HIGHER CONFIDENCE IN TEMPERATURES REMAINING BELOW AVERAGE AS GUIDANCE AGREES ON COLD UPPER TROUGH SETTING UP SHOP OVER THE AREA. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * TIMING OF WIND SHIFT TO EAST-SOUTHEAST WINDS LATE THIS AFTERNOON/EARLY EVENING. * WINDS AROUND DUE SOUTH AT TIMES ON SUNDAY. * SMALL CHANCE FOR THUNDERSTORMS VERY EARLY SUNDAY MORNING...THEN A BETTER CHANCE LATE SUNDAY AFTERNOON INTO THE EVENING. //DISCUSSION...UPDATED 18Z... HIGH PRESSURE OVER INDIANA AND EASTERN ILLINOIS WILL DEPART TO THE SOUTHEAST LATE TONIGHT. IN THE MEANTIME...THE LIGHT WIND REGIME FROM THE HIGH ALLOWED FOR A LAKE BREEZE TO DEVELOP. THIS LAKE BREEZE HOWEVER HAS HAD DIFFICULTY ADVANCING INLAND AS MIXING AND WEST TO SOUTHWEST GUSTS HAVE BEEN OBSERVED OVER INLAND PORTIONS OF NORTHERN ILLINOIS...INCLUDING ORD AND MDW. THE EFFECTS OF THESE WINDS HAVE ALREADY BEEN SEEN ON THE ORD TERMINAL DOPPLER WEATHER RADAR...WITH THE LAKE BREEZE HAVING BECOME STATIONARY...EVEN RETREATING SLIGHTLY. WITH LOSS OF MIXING LATE IN THE AFTERNOON/EARLY EVE...THE LAKE BREEZE SHOULD PROPAGATE INLAND SOME MORE. IN ADDITION...THE SYNOPTIC FLOW WILL TURN SOUTHEAST DURING THE EARLY TO MID EVE AS THE HIGH PRESSURE MOVES AWAY. THE SOUTHERLY WINDS WILL LIKELY PERSIST INTO SUNDAY AND INCREASE IN SPEED. THE OUTER EDGE OF WARM AIR ADVECTION AND ELEVATED INSTABILITY WILL LIFT OVER THE REGION LATE TONIGHT/VERY EARLY SUNDAY MORNING. ISOLATED/SCATTERED SHRA AND POSSIBLY A FEW TSRA ARE FAVORED TO ACCOMPANY THIS FORCING. A BETTER CHANCE FOR THUNDER WILL ARRIVE NEAR THE WARM FRONT LATER SUNDAY AFTERNOON INTO THE EVENING. SOME OF THESE STORMS MAY BE DEEPER AND STRONGER. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * LOW IN WIND SHIFT TIMING TO EAST SOUTHEAST AND MEDIUM THAT SPEEDS WILL BE 8 KT OR LESS AFTER SHIFTING TO SOUTHEAST. * MEDIUM IN WINDS ON SUNDAY. * LOW IN ANY STORMS VERY EARLY SUNDAY MORNING AND THEN MEDIUM IN ISOLATED/SCATTERED STORMS BY LATE SUNDAY AFTERNOON. //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PERIODS OF SHRA/TSRA POSSIBLE. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. GUSTY SOUTHWEST WINDS. TUESDAY THROUGH FRIDAY...CHANCE OF SHRA. MTF/KJB && .MARINE... 201 AM CDT A SURFACE RIDGE OF HIGH PRESSURE WILL MOVE ACROSS LAKE MICHIGAN LATER TODAY...AND THIS WILL PROVIDE A PERIOD OF LIGHT AND VARIABLE WINDS ACROSS THE SOUTHERN PORTION OF THE LAKE THIS AFTERNOON. LAKE BREEZE INFLUENCES WILL LIKELY PRODUCE A LIGHT ONSHORE FLOW ACROSS THE NEAR SHORE WATERS. THE WINDS WILL ULTIMATELY BECOME SOUTHERLY AGAIN BY SUNDAY IN RESPONSE TO LOW PRESSURE TAKING SHAPE ACROSS THE PLAINS. THIS AREA OF LOW PRESSURE IS EXPECTED TO SHIFT NORTHEASTWARD ACROSS THE MID AND UPPER MISSISSIPPI VALLEY BY LATE MONDAY. AS THIS OCCURS...AN ASSOCIATED WARM FRONT IS EXPECTED TO LIFT NORTHWARD UP THE LAKE. A PERIOD OF STRONGER SOUTHERLY WINDS UP AROUND 20-25 KT WILL LIKELY ENSUE IN THE WAKE OF THIS FRONTAL BOUNDARY...WITH AN EAST-SOUTHEASTERLY WIND COMPONENT LIKELY NORTH OF THE BOUNDARY. THESE SOUTHERLY WINDS WILL LIKELY CONTINUE THROUGH MONDAY NIGHT...BEFORE A COLD FRONT SHIFTS ACROSS THE LAKE SOMETIME ON TUESDAY...SHIFTING THE WINDS OUT OF THE WEST-NORTHWEST. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1232 PM CDT Sat May 10 2014 .DISCUSSION... ISSUED 945 AM CDT Sat May 10 2014 14z/9am surface analysis shows stationary frontal boundary draped across the far SE KILX CWA, generally south of a Robinson to Flora line. Warm/moist airmass is still in place near and south of the boundary where dewpoints are hovering in the middle 60s. Widely scattered thunderstorms are ongoing south of the front near the I-64 corridor: however, with a weak upper-level impulse currently tracking out of Missouri into the Ohio River Valley, would not be surprised to see a couple of cells develop further north near the front. Latest RAP model hints at this through early afternoon before upper wave exits into Indiana. As such, have decided to include isolated thunder south of I-70. Further north, mostly sunny and drier conditions are noted, with dewpoints only in the 40s. Another upper wave is evident on water vapor imagery over Nebraska: however, this feature will lift northeastward and not impact the weather across central Illinois today. End result will be a warm/dry day with highs in the upper 70s and lower 80s. As upper low over Washington/Oregon digs southward west of the Rockies, downstream ridging will allow frontal boundary to lift back northward tonight. Showers and thunderstorms will develop along the boundary, but precip will hold off until evening. Zone update has already been issued. Barnes && .AVIATION... ISSUED 1232 PM CDT Sat May 10 2014 Dry/stable airmass will remain in place across central Illinois this afternoon, resulting in mostly clear skies and light winds. As a warm frontal boundary begins to lift back northward tonight, scattered showers and thunderstorms will develop and track through the area. Timing of convection remains in question, as stable surface-based layer will slow eastward progression of any storms that develop west of the Mississippi River this afternoon. Most high-res model guidance suggests convective development along/north of the warm front across western Missouri over the next couple of hours, with storms tracking E/SE along the boundary into south-central Illinois by evening. Trajectory of storms may keep them south of the central Illinois terminals until later in the evening when front lifts further northward and low-level jet strengthens across the area. Due to low confidence concerning timing and areal coverage, have opted to only go with VCTS in the TAFs at this time. Will introduce VCTS at KSPI earliest by 03z, then further northeast at KCMI by 07z. Front will lift north of the area by Sunday morning, taking best focus for additional convection into northern Illinois. Light SE winds this afternoon will become southerly and will increase into the 10 to 15kt range behind the warm front on Sunday. Barnes && .PREV DISCUSSION... ISSUED 330 AM CDT Sat May 10 2014 SHORT TERM...Today through Tuesday A nice day in store for central IL today as skies become partly to mostly sunny and highs in the upper 70s to around 80F. A frontal boundary lingers in far southeast CWA early this morning and have isolated showers and thunderstorms possible near Lawrenceville until mid morning until front pushes slowly se of there. More active weather pattern takes shape from tonight through the middle of next week, with daily chances of showers and thunderstorms. SPC has areas sw of Canton to Lincoln to Effingham in a slight risk of severe storms tonight as warm front lift north with increasing chances of showers and thunderstorms from west to east during the night. Areas from I-72 north are in a slight risk of severe on Sunday afternoon into Sunday night. And areas from I-55 west are in a slight risk of severe storms again later Monday afternoon and Monday night as a cold front moves east across IL Monday night. Have lowered chances of showers and thunderstorms Sunday night and Monday morning especially southern counties as best convection chances shift north with warm front. Warm weather in store through Monday with highs Sunday/Monday in the low to mid 80s. Monday has potential to be the warmest day with 850 mb temps elevating to near 20C and this depends on how much sunshine we see. Will have breezy south southwest winds Monday and increase wind speeds then. On Tue kept likely chances of showers and isolated thunderstorms over eastern IL closer to departing cold front while chance of showers west of I-57 Tue. Highs Tue range from mid 60s over IL river valley to mid 70s near the Wabash River. LONG TERM...Tuesday night through Saturday Unsettled weather pattern looks to continue at least Tue night and Wed as strong upper level trof shifts east into IL and ECMWF model even shows surface low pressure lifting ne and passing se of central IL Wed and bringing widespread showers to the area. If this pans out may need to increase pops further on Wed and have cooler temps. Large upper level trof over the Midwest and Great Lakes region continues for 2nd half of next week keeping temps below normal along with lingering chances of light rain showers. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1056 AM CDT SAT MAY 10 2014 .DISCUSSION... 252 AM CDT PRIMARY FORECAST CHALLENGE THIS MORNING REMAINS THE CONVECTIVE POTENTIAL STARTING TONIGHT AND CONTINUING AT TIMES THROUGH MONDAY NIGHT. SECONDARY CONCERNS INCLUDE TEMPERATURES SUNDAY INTO MONDAY AND THEN PRECIP CHANCES NEXT WEEK. HIGH PRESSURE OVER THE REGION TODAY SHOULD RESULT IN A PRETTY NICE DAY OVERALL. SLUG OF HIGH CLOUDINESS OVER MISSOURI IS ASSOCIATED WITH A SHORTWAVE ALOFT...MUCH MORE DEFINED AT 250MB THAN AT 500MB WITH VERY LITTLE REFLECTION AT 700MB. DRY LOW LEVELS AND ABSENCE OF FORCING SHOULD KEEP THIS ONLY A HIGH CLOUD PRODUCER AND MAINLY THIS MORNING. LIGHT WIND REGIME SHOULD ALLOW LAKE BREEZE TO FORM BY EARLY AFTERNOON WITH FALLING TEMPS NEAR THE LAKE THIS AFTERNOON...BUT FAIRLY MILD CONDITIONS AWAY FROM THE LAKE. TONIGHT LOW LEVEL JET SHOULD RESULT IN STRENGTHENING LOW LEVEL THETA-E ADVECTION AND LIKELY THE DEVELOPING OF SHOWERS AND THUNDERSTORMS OVER MISSOURI THIS EVENING. THIS ACTIVITY IS EXPECTED TO PUSH EAST INTO ILLINOIS LATE TONIGHT...HOWEVER GUIDANCE IS INCREASINGLY SUGGESTING THAT THE STRONGEST MOISTURE CONVERGENCE WILL REMAIN FARTHER SOUTH ACROSS CENTRAL ILLINOIS WITH FAR LESSER SUPPORT FROM PRECIP FARTHER NORTH. HAVE DECREASED POPS CONSIDERABLY OVER NORTHERN 2/3RD OF CWA...MAINTAINING CHANCE POPS MOSTLY FOR CONTINUITY SAKE AS IT LOOKS MORE AND MORE LIKELY THAT IT COULD STAY DRY ALTOGETHER NORTH OF I-80. FAR SOUTHERN CWA STANDS A BETTER CHANCE OF SEEING SOME OF THIS CONVECTION AND HAVE MAINTAINED HIGHER POPS THERE. SUNDAY SHOULD SEE DEVELOPING SOUTHERLY FLOW AS CYCLOGENESIS TAKES PLACE OVER THE PLAINS WITH STRENGTHENING WARM AND MOIST ADVECTION INTO THE AREA. DOES APPEAR AS THOUGH A SOMEWHAT ILL DEFINED WARM FRONT WILL DEVELOP AND LIFT NORTH ACROSS THE CWA SUNDAY BUT OTHERWISE SYNOPTIC SCALE FORCING LOOKS SOMEWHAT NEBULOUS...PARTICULARLY IN LIGHT IN STRONG HEIGHT RISES DOWNSTREAM OF THE AMPLIFYING TROUGH TO OUR WEST. CERTAINLY PLAUSIBLE THAT REMNANT MCV FROM TODAY`S CONVECTION OVER THE PLAINS OR FORCING ALONG THE WEAK WARM FRONT COULD BE ENOUGH TO KICK OF THUNDERSTORMS SUNDAY AFTERNOON...BUT OVERALL SYNOPTIC PATTERN WOULD ARGUE FOR LARGELY A RAIN-FREE DAY ACROSS THE CWA AND HAVE ATTEMPTED TO SCALE BACK POPS SOME. WORTH NOTING HOWEVER...THAT MODERATE INSTABILITY SHOULD DEVELOP WITH THE INCREASINGLY WARM/HUMID AIRMASS AND WITH STILL RESPECTABLE VALUES OF DEEP LAYER SHEAR THREAT DOES EXISTS FOR ANY CONVECTION THAT DOES DEVELOP SUNDAY AFTERNOON TO BE SEVERE. NOT TO MENTION THAT ILLINOIS WARM FRONTS SEEM TO LIKE TO PRODUCE "SURPRISES" THIS TIME OF YEAR. SOUTHERLY WINDS ON SUNDAY LOOK LIGHT ENOUGH FOR AT LEAST AN ILLINOIS SHORE LAKE BREEZE TO DEVELOP IN THE AFTERNOON...PARTICULARLY IF WARM FRONT BECOMES BETTER DEFINED AND WINDS MORE BACKED AHEAD OF IT. ASSUMING THIS SCENARIO PANS OUT DID KEEP LAKE COOLING IN THE GRIDS SUNDAY WITH FAIRLY WARM TEMPERATURES EXPECTED ELSEWHERE. BY SUNDAY NIGHT THE MAJORITY OF GUIDANCE AGREES THAT THE WARM FRONT WILL BECOME BETTER DEFINED TO OUR NORTH OVER WISCONSIN WITH FOCUS FOR POTENTIALLY SIGNIFICANT CONVECTIVE EVENT NORTH OF THE BORDER WITH OUR CWA JUST UNSEASONABLY WARM AND STEAMY WITH LOWS STRUGGLING TO DIP BELOW 70 DEGREES AS DEWPOINTS CLIMB WELL INTO THE 60S AND MODERATELY STRONG WINDS THROUGH THE NIGHT. GFS IS THE ODD MAN OUT KEEPING WARM FRONT AND SIGNIFICANT CONVECTION FARTHER SOUTH INTO OUR CWA. HAVE TRENDED POPS DOWN SUNDAY NIGHT...ESPECIALLY SOUTHERN CWA...BUT RELUCTANT TO GO TOO LOW GIVEN GFS SOLUTION AND POSSIBILITY THAT EVEN IF OTHER MODELS VERIFY OUTFLOW COULD PUSH SOUTH AND ALLOW CONVECTION TO PROPAGATE INTO OUR FAR NORTHERN CWA. UNUSUALLY HIGH PWATS AND SLOW MOVING NATURE OF WARM FRONT RAISE CONCERNS FOR HEAVY RAINFALL AND FLASH FLOODING...THOUGH THANKFULLY THAT APPEARS TO BE MORE OF A THREAT NORTH OF THE STATE LINE IN WISCONSIN. SUNDAY AFTERNOON`S LIKELY SEVERE CONVECTION OVER THE EASTERN PLAINS WILL PROBABLY SPILL A FAIR AMOUNT OF DEBRIS CLOUDINESS AND POSSIBLY SOME SHOWERS INTO THE AREA EARLY MONDAY...BUT AS THIS CONVECTION MOVES AWAY FROM BETTER UPPER SUPPORT AND INTO MORE CAPPED ENVIRONMENT TOWARD THE MS VALLEY WOULD EXPECT IT TO WEAKEN OR DISSIPATE ALTOGETHER. STRONG SOUTHERLY WINDS AND 925MB TEMPS PROGGED TO GET ABOVE 20C MONDAY COULD EASILY RESULT IN HIGHS IN THE UPPER 80S OVER MUCH OF THE CWA...THOUGH UNCERTAINTIES REGARDING EXTENT OF DEBRIS FROM SUNDAY`S PLAINS CONVECTION AND LOWER GUIDANCE VALUES HAVE PROMPTED ME TO BE MORE RESTRAINED IN MY BUMPING UP OVER TEMPS MONDAY. LOOKS LIKE STRONG TO SEVERE THUNDERSTORMS WILL DEVELOP TO OUR WEST MONDAY AFTERNOON WITH STORMS MOVING INTO OUR AREA MONDAY NIGHT IN ADVANCE OF APPROACHING STRONG COLD FRONT. GUIDANCE HAS CONTINUED TO KEEP THE STRONGER WINDS ALOFT BEHIND THE COLD FRONT RESULTING IN MORE MARGINAL SHEAR VALUES IN THE WARM SECTOR MONDAY. CERTAINLY LOOKS TO BE ENOUGH SHEAR FOR AN ORGANIZED MULTIPLE EVENT TO DEVELOP...BUT SOMEWHAT MARGINAL FOR A SUBSTANTIAL SEVERE THREAT LOCALLY...ESPECIALLY WITH TIMING OF STORMS ARRIVING AFTER DARK MONDAY NIGHT. THE GFS IS REALLY AGGRESSIVE IN DEVELOPING POST FRONTAL PRECIPITATION TUESDAY WITH OTHER GUIDANCE LESS GUNG-HO. OPTED TO HANG ONTO CHANCE POPS TUESDAY MORNING AS A NOD TO THE GFS BUT WOULDN`T BE SURPRISED IF MOST AREAS END UP DRY ALTOGETHER TUESDAY. PRETTY BIG UNCERTAINTIES LINGER WEDNESDAY THROUGH FRIDAY IN THE DETAILS OF ANY PRECIP CHANCES...THOUGH IT LOOKS LIKE THE MAJORITY OF THE TIME FRAME WILL BE DRY DESPITE THE NEED TO MAINTAIN LOW CHANCES POPS THROUGH THE PERIOD. HIGHER CONFIDENCE IN TEMPERATURES REMAINING BELOW AVERAGE AS GUIDANCE AGREES ON COLD UPPER TROUGH SETTING UP SHOP OVER THE AREA. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * TIMING OF LAKE BREEZE AND WIND SHIFT TO EAST-SOUTHEAST WINDS LATE THIS AFTERNOON/EARLY EVENING. * INCREASING CHANCES OF THUNDERSTORMS INTO SUNDAY. MTF/KJB //DISCUSSION...UPDATED 12Z... OVERALL A FAIRLY QUIET WEATHER DAY APPEARS IN STORE FOR THE AREA TODAY. THE ONLY MINOR CONCERNS WILL BE THE POTENTIAL FOR A LAKE BREEZE TO SHIFT THE WINDS EASTERLY VERY LATE THIS AFTERNOON AT THE EASTERN TERMINALS...AND A SMALL CHANCE FOR THUNDERSTORMS LATE TONIGHT INTO EARLY SUNDAY. A SURFACE RIDGE OF HIGH PRESSURE...CURRENTLY IN PLACE ACROSS THE REGION...WILL CONTINUE TO SUPPORT A FAIRLY LIGHT SYNOPTIC WIND FIELD ACROSS THE AREA TODAY. THIS SHOULD PROMOTE A LAKE BREEZE TO DEVELOP ALONG THE NORTHEASTERN ILLINOIS SHORELINE LATER TODAY. THE EXACT TIMING OF THIS BOUNDARY...AND THE ASSOCIATED WIND SHIFT...REACHING KORD AND KMDW REMAINS A BIT UNCERTAIN. HOWEVER...IT APPEARS THAT THIS WIND SHIFT SHOULD OCCUR EITHER VERY LATE THIS AFTERNOON...AFTER 22 UTC...OR EARLY THIS EVENING AS THE LARGELY SCALE WIND PATTERN BEGINS TO FAVOR AN EAST-SOUTHEASTERLY WIND COMPONENT. WIND SPEEDS WITH THE WIND SHIFT LOOK TO REMAIN AT OR UNDER 10 KT. ANOTHER STORM SYSTEM WILL BE TAKING SHAPE ACROSS THE PLAINS STATES LATE TODAY AND TONIGHT. THIS SYSTEM WILL LIKELY BE THE CULPRIT FOR ANOTHER PERIOD OR TWO OF THUNDERSTORMS ACROSS THE AREA LATER IN THE WEEKEND THROUGH EARLY NEXT WEEK. SOME OF THESE SHOWERS AND THUNDERSTORMS COULD ENTER THE PICTURE AS EARLY AS LATER TONIGHT INTO EARLY SUNDAY. HOWEVER...IT APPEARS THAT THE BEST CHANCES FOR CONVECTIVE ACTIVITY TONIGHT WILL REMAIN SOUTH OF THE TERMINALS. BETTER CHANCES FOR CONVECTIVE ACTIVITY APPEAR TO BE IN STORE ACROSS NORTHERN ILLINOIS LATER SUNDAY AS A WARM FRONT LIFTS ACROSS THE AREA. THIS THREAT IS CURRENTLY BEYOND THE 30 HOUR KORD TAF. THE ONLY CHANGE TO THE EXTEND PORTION OF THE TAFS WAS TO ADD A PROB 30 GROUP FOR -SHRA LATE TONIGHT INTO EARLY SUNDAY TO COVER THE LOW THREAT FOR SOME ACTIVITY IMPACTING NORTHERN ILLINOIS. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM IN TIMING OF SHIFT TO EAST-SOUTHEAST THIS AFTERNOON/EVENING. LOW-MEDIUM IN SPEEDS BEING 8 KT OR LESS BEHIND WIND SHIFT. * LOW ON CONVECTIVE ACTIVITY IMPACTING THE TERMINALS LATE TONIGHT. MTF/KJB //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PERIODS OF SHRA/TSRA POSSIBLE. MONDAY...PERIODS OF SHRA/TSRA POSSIBLE. GUSTY SOUTHWEST WINDS. TUESDAY THROUGH FRIDAY...CHANCE OF SHRA. KJB && .MARINE... 201 AM CDT A SURFACE RIDGE OF HIGH PRESSURE WILL MOVE ACROSS LAKE MICHIGAN LATER TODAY...AND THIS WILL PROVIDE A PERIOD OF LIGHT AND VARIABLE WINDS ACROSS THE SOUTHERN PORTION OF THE LAKE THIS AFTERNOON. LAKE BREEZE INFLUENCES WILL LIKELY PRODUCE A LIGHT ONSHORE FLOW ACROSS THE NEAR SHORE WATERS. THE WINDS WILL ULTIMATELY BECOME SOUTHERLY AGAIN BY SUNDAY IN RESPONSE TO LOW PRESSURE TAKING SHAPE ACROSS THE PLAINS. THIS AREA OF LOW PRESSURE IS EXPECTED TO SHIFT NORTHEASTWARD ACROSS THE MID AND UPPER MISSISSIPPI VALLEY BY LATE MONDAY. AS THIS OCCURS...AN ASSOCIATED WARM FRONT IS EXPECTED TO LIFT NORTHWARD UP THE LAKE. A PERIOD OF STRONGER SOUTHERLY WINDS UP AROUND 20-25 KT WILL LIKELY ENSUE IN THE WAKE OF THIS FRONTAL BOUNDARY...WITH AN EAST-SOUTHEASTERLY WIND COMPONENT LIKELY NORTH OF THE BOUNDARY. THESE SOUTHERLY WINDS WILL LIKELY CONTINUE THROUGH MONDAY NIGHT...BEFORE A COLD FRONT SHIFTS ACROSS THE LAKE SOMETIME ON TUESDAY...SHIFTING THE WINDS OUT OF THE WEST-NORTHWEST. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 945 AM CDT Sat May 10 2014 .DISCUSSION... ISSUED 945 AM CDT Sat May 10 2014 14z/9am surface analysis shows stationary frontal boundary draped across the far SE KILX CWA, generally south of a Robinson to Flora line. Warm/moist airmass is still in place near and south of the boundary where dewpoints are hovering in the middle 60s. Widely scattered thunderstorms are ongoing south of the front near the I-64 corridor: however, with a weak upper-level impulse currently tracking out of Missouri into the Ohio River Valley, would not be surprised to see a couple of cells develop further north near the front. Latest RAP model hints at this through early afternoon before upper wave exits into Indiana. As such, have decided to include isolated thunder south of I-70. Further north, mostly sunny and drier conditions are noted, with dewpoints only in the 40s. Another upper wave is evident on water vapor imagery over Nebraska: however, this feature will lift northeastward and not impact the weather across central Illinois today. End result will be a warm/dry day with highs in the upper 70s and lower 80s. As upper low over Washington/Oregon digs southward west of the Rockies, downstream ridging will allow frontal boundary to lift back northward tonight. Showers and thunderstorms will develop along the boundary, but precip will hold off until evening. Zone update has already been issued. Barnes && .AVIATION... ISSUED 658 AM CDT Sat May 10 2014 The stationary front across southeast IL will linger in place south of the terminal sites today, with BKN high clouds north of the front in central Illinois through the day. Winds will generally be less than 10 kt from the east-southeast until afternoon, when wind speeds increase between 10-14kt for the western terminals. Storm chances will be tied to the northward advance of the front as a warm front tonight. Storms are forecast to develop across Missouri this evening and advance from west to east across the area tonight. It appears that storms could reach as far east as PIA to SPI by 02z. The NCEP 4km WRF output has the initial wave of storms in a 4 hour window, so tempo`s for MVFR vis in TSRA were included at all TAF sites for late evening to just after midnight. Storm chances could linger through morning under VCTS conditions, but SPI and PIA could see a break develop by 10z. Shimon && .PREV DISCUSSION... ISSUED 330 AM CDT Sat May 10 2014 SHORT TERM...Today through Tuesday A nice day in store for central IL today as skies become partly to mostly sunny and highs in the upper 70s to around 80F. A frontal boundary lingers in far southeast CWA early this morning and have isolated showers and thunderstorms possible near Lawrenceville until mid morning until front pushes slowly se of there. More active weather pattern takes shape from tonight through the middle of next week, with daily chances of showers and thunderstorms. SPC has areas sw of Canton to Lincoln to Effingham in a slight risk of severe storms tonight as warm front lift north with increasing chances of showers and thunderstorms from west to east during the night. Areas from I-72 north are in a slight risk of severe on Sunday afternoon into Sunday night. And areas from I-55 west are in a slight risk of severe storms again later Monday afternoon and Monday night as a cold front moves east across IL Monday night. Have lowered chances of showers and thunderstorms Sunday night and Monday morning especially southern counties as best convection chances shift north with warm front. Warm weather in store through Monday with highs Sunday/Monday in the low to mid 80s. Monday has potential to be the warmest day with 850 mb temps elevating to near 20C and this depends on how much sunshine we see. Will have breezy south southwest winds Monday and increase wind speeds then. On Tue kept likely chances of showers and isolated thunderstorms over eastern IL closer to departing cold front while chance of showers west of I-57 Tue. Highs Tue range from mid 60s over IL river valley to mid 70s near the Wabash River. LONG TERM...Tuesday night through Saturday Unsettled weather pattern looks to continue at least Tue night and Wed as strong upper level trof shifts east into IL and ECMWF model even shows surface low pressure lifting ne and passing se of central IL Wed and bringing widespread showers to the area. If this pans out may need to increase pops further on Wed and have cooler temps. Large upper level trof over the Midwest and Great Lakes region continues for 2nd half of next week keeping temps below normal along with lingering chances of light rain showers. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
216 AM EDT SAT MAY 10 2014 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 251 PM EDT FRI MAY 9 2014 A FEW THUNDERSTORMS REMAIN POSSIBLE OVERNIGHT AS A COLD FRONT MOVES ACROSS CENTRAL INDIANA AFTER A MAINLY DRY SATURDAY...ANOTHER SYSTEM WILL RESULT IN PROLONGED THUNDERSTORM CHANCES FROM SATURDAY NIGHT THROUGH WEDNESDAY WITH LINGERING SHOWERS AFTER THAT. TEMPERATURES WILL REMAIN ABOVE NORMAL IN THE 70S AND 80S UNTIL A MIDWEEK COLD FRONT MOVES THROUGH NEXT WEEK. THEN...TEMPERATURES WILL BECOME BELOW NORMAL IN THE 60S AND CONTINUE THAT WAY THROUGH THE LATE WEEK. && .NEAR TERM /OVERNIGHT/... ISSUED AT 1017 PM EDT FRI MAY 9 2014 CONVECTION AHEAD OF THE FRONT HAS FINALLY MOVED OFF TO THE NORTHEAST WITH THE WEAKENING WAVE ALOFT. CLOUDS REMAIN ACROSS MUCH OF THE FORECAST AREA WITH SOME CLEARING INTO THE FAR NORTHWEST COUNTIES AS SOME SUBSIDENCE HAS WORKED IN BEHIND THE UPPER WAVE. TEMPS REMAINED LARGELY IN THE 60S AS OF 02Z. WHILE THE BULK OF THE CONVECTION HAS FINISHED FOR THE NIGHT... CANNOT ENTIRELY RULE OUT ANY ADDITIONAL ACTIVITY WITH THE FRONT TAKING MOST OF THE NIGHT TO SAG INTO SOUTHERN COUNTIES. 00Z NAM AND CURRENT HRRR HINT AT SOME REDEVELOPMENT OVERNIGHT...FOCUSED SOUTH OF INTERSTATE 70 AND MAINLY AFTER 07-08Z. HAVE ADJUSTED POPS DOWN TO 20-30 FOR ALL BUT THE NORTHWEST COUNTIES FOR THE REMAINDER OF THE NIGHT. ADJUSTED LOW TEMPS UP A DEGREE OR TWO IN THE SOUTH WITH THE FRONT NOT MAKING IT INTO SOUTHERN COUNTIES UNTIL LATE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 251 PM EDT FRI MAY 9 2014 SHOWER OR THUNDERSTORM CHANCES WILL BE THE MAIN CONCERN FOR THE SHORT TERM. THE 00Z ECMWF AND ITS ENSEMBLES HAVE BEEN MUCH MORE CONSISTENT WITH THE SHORT TERM SYNOPTIC PATTERN. A COLD FRONT WILL STALL NEAR OUR SOUTHERN BORDER ON SATURDAY MORNING AND RETURN NORTH AS A WARM FRONT SATURDAY NIGHT AND SUNDAY IN RESPONSE TO A SURFACE LOW NEAR THE OKLAHOMA PANHANDLE SPAWNED FROM AN UPSTREAM UPPER LOW NEAR THE FOUR CORNERS REGION. THUS...WITH THE FRONT NEARBY SATURDAY MORNING ALONG WITH LINGERING INSTABILITY...WILL HOLD ON TO SMALL THUNDERSTORM CHANCES SATURDAY MORNING AND BRING BACK HIGH CHANCES BY SATURDAY NIGHT AS THE WARM FRONT APPROACHES. THE AREA SHOULD BE IN THE WARM SECTOR AFTER THAT AS SURFACE LOW LIFTS NORTHEAST TO THE UPPER MIDWEST MONDAY. SO...KEPT POPS SUNDAY...ALBEIT LOW POPS WITH AN ASSOCIATED COLD FRONT WELL TO THE WEST...ACROSS THE PLAINS. BLEND OF COOLER 12Z NAM AND WARMER 12Z GFS LOOKS OK FOR THE SHORT TERM AND MATCHES WELL WITH 12Z ALLBLEND. SHOULD CONTINUE TO SEE ABOVE NORMAL TEMPERATURES WITH AFTERNOON HIGHS IN MID TO UPPER 70S SATURDAY AND UPPER 70S AND LOWER 80S SUNDAY AND MONDAY. && .LONG TERM /TUESDAY THROUGH SATURDAY/... ISSUED AT 207 AM EDT SAT MAY 10 2014 CONFIDENCE IS GROWING FOR A RAIN EVENING SOMETIME ON TUESDAY INTO WEDNESDAY HOWEVER CONFIDENCE IN TIMING REMAINS LOW. GFS AND ECMWF CONTINUE TO SUGGEST A WARM AND MOIST AIR MASS IN PLACE OVER INDIANA AHEAD OF AN APPROACHING COLD FRONT AND UPPER WAVE. FARTHER DOWNSTREAM A BLOCKING RIDGE WAS IN PLACE. THE GFS IS QUICKER WITH THE PROGRESSION OF THE FRONT THAN THE ECMWF AND WITH THE BLOCKING RIDGE IN PLACE TO THE EAST...A SLOWER PROGRESSION IS PREFERRED. NONETHELESS...PRECIP LOOKS LIKE A GOOD BET IN THE MIDDLE OF NEXT WEEK AS THIS SYSTEM PASSES. IN THE WAKE OF THAT FRONTAL PASSAGE...BOTH THE GFS AND ECMWF KEEP BROAD UPPER CYCLONIC FLOW ACROSS THE AREA...HOWEVER MOISTURE WILL REMAIN LIMITED IN THE LOWER LEVELS. WILL TREND POPS AND TEMPS LOWERS AMID A COOLER AND DRIER FLOW INTO THE AREA FOR LATE NEXT WEEK. && .AVIATION /DISCUSSION FOR 100600Z TAF UPDATE/... ISSUED AT 1208 PM EDT FRI MAY 9 2014 SHORT TERM MODELS SHOWING VARIABILITY ABOUT RAIN/THUNDER DURING THE OVERNIGHT...BUT A COUPLE ARE SHOWING THE FRONT STALLING OUT AND RAIN OR POSSIBLY THUNDER ALONG AN EAST-WEST AREA THAT WOULD INCLUDE ALL SITES BUT KLAF. PUT A TEMPO SHOWER IN AT KHUF AND KIND AND PUT A PREVAILING SHOWER IN AT KBMG. GUIDANCE INDICATES SOME MVFR CEILINGS/VISIBILITIES WITH THIS SO INCLUDED THEM AS WELL. ANY RESTRICTIONS THAT DO DEVELOP SHOULD BE GONE BY AROUND 13Z AND THEN VFR FOR THE DAY. WINDS WILL DROP OFF OVER THE NEXT COUPLE OF HOURS && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MK/RYAN NEAR TERM...RYAN SHORT TERM...MK LONG TERM....PUMA AVIATION...CP/JP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1208 PM EDT FRI MAY 9 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 251 PM EDT FRI MAY 9 2014 A FEW THUNDERSTORMS REMAIN POSSIBLE OVERNIGHT AS A COLD FRONT MOVES ACROSS CENTRAL INDIANA AFTER A MAINLY DRY SATURDAY...ANOTHER SYSTEM WILL RESULT IN PROLONGED THUNDERSTORM CHANCES FROM SATURDAY NIGHT THROUGH WEDNESDAY WITH LINGERING SHOWERS AFTER THAT. TEMPERATURES WILL REMAIN ABOVE NORMAL IN THE 70S AND 80S UNTIL A MIDWEEK COLD FRONT MOVES THROUGH NEXT WEEK. THEN...TEMPERATURES WILL BECOME BELOW NORMAL IN THE 60S AND CONTINUE THAT WAY THROUGH THE LATE WEEK. && .NEAR TERM /OVERNIGHT/... ISSUED AT 1017 PM EDT FRI MAY 9 2014 CONVECTION AHEAD OF THE FRONT HAS FINALLY MOVED OFF TO THE NORTHEAST WITH THE WEAKENING WAVE ALOFT. CLOUDS REMAIN ACROSS MUCH OF THE FORECAST AREA WITH SOME CLEARING INTO THE FAR NORTHWEST COUNTIES AS SOME SUBSIDENCE HAS WORKED IN BEHIND THE UPPER WAVE. TEMPS REMAINED LARGELY IN THE 60S AS OF 02Z. WHILE THE BULK OF THE CONVECTION HAS FINISHED FOR THE NIGHT... CANNOT ENTIRELY RULE OUT ANY ADDITIONAL ACTIVITY WITH THE FRONT TAKING MOST OF THE NIGHT TO SAG INTO SOUTHERN COUNTIES. 00Z NAM AND CURRENT HRRR HINT AT SOME REDEVELOPMENT OVERNIGHT...FOCUSED SOUTH OF INTERSTATE 70 AND MAINLY AFTER 07-08Z. HAVE ADJUSTED POPS DOWN TO 20-30 FOR ALL BUT THE NORTHWEST COUNTIES FOR THE REMAINDER OF THE NIGHT. ADJUSTED LOW TEMPS UP A DEGREE OR TWO IN THE SOUTH WITH THE FRONT NOT MAKING IT INTO SOUTHERN COUNTIES UNTIL LATE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 251 PM EDT FRI MAY 9 2014 SHOWER OR THUNDERSTORM CHANCES WILL BE THE MAIN CONCERN FOR THE SHORT TERM. THE 00Z ECMWF AND ITS ENSEMBLES HAVE BEEN MUCH MORE CONSISTENT WITH THE SHORT TERM SYNOPTIC PATTERN. A COLD FRONT WILL STALL NEAR OUR SOUTHERN BORDER ON SATURDAY MORNING AND RETURN NORTH AS A WARM FRONT SATURDAY NIGHT AND SUNDAY IN RESPONSE TO A SURFACE LOW NEAR THE OKLAHOMA PANHANDLE SPAWNED FROM AN UPSTREAM UPPER LOW NEAR THE FOUR CORNERS REGION. THUS...WITH THE FRONT NEARBY SATURDAY MORNING ALONG WITH LINGERING INSTABILITY...WILL HOLD ON TO SMALL THUNDERSTORM CHANCES SATURDAY MORNING AND BRING BACK HIGH CHANCES BY SATURDAY NIGHT AS THE WARM FRONT APPROACHES. THE AREA SHOULD BE IN THE WARM SECTOR AFTER THAT AS SURFACE LOW LIFTS NORTHEAST TO THE UPPER MIDWEST MONDAY. SO...KEPT POPS SUNDAY...ALBEIT LOW POPS WITH AN ASSOCIATED COLD FRONT WELL TO THE WEST...ACROSS THE PLAINS. BLEND OF COOLER 12Z NAM AND WARMER 12Z GFS LOOKS OK FOR THE SHORT TERM AND MATCHES WELL WITH 12Z ALLBLEND. SHOULD CONTINUE TO SEE ABOVE NORMAL TEMPERATURES WITH AFTERNOON HIGHS IN MID TO UPPER 70S SATURDAY AND UPPER 70S AND LOWER 80S SUNDAY AND MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 251 PM EDT FRI MAY 9 2014 A COLD FRONT IS PROGGED TO AFFECT CENTRAL INDIANA AT THE BEGINNING OF THE EXTENDED PERIOD. GFS AND EURO ARE IN GOOD AGREEMENT WITH TIMING...AND LATEST INITIALIZATION IS SHOWING LIKELY POPS FOR TUESDAY. AFTER A BRIEF DRY SLOT ON WEDNESDAY...MODELS HAVE A BROAD AREA OF LOW PRESSURE ALOFT EXTENDING FROM ONTARIO INTO THE MISSISSIPPI VALLEY. THIS SHOULD GENERATE ENOUGH LIFT FOR ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH THURSDAY NIGHT. AFTER THAT...A LARGE RIDGE OF SURFACE HIGH PRESSURE IS EXPECTED TO MOVE INTO THE CENTRAL PLAINS...BUT TIMING BECOMES INCONSISTENT IN MODELS AT THAT POINT. THE EURO BRINGS DRIER CONDITIONS INTO THE FORECAST AREA EARLIER THAN THE GFS. MEANWHILE...THE LATEST INITIALIZATION FAVORS SLIGHT CHANCE POPS THROUGH THE REMAINDER OF EXTENDED PERIOD. FOR NOW...WILL KEEP INITIALIZATION FORECAST UNTIL MODELS BECOME MORE CONSISTENT. TEMPERATURES WILL GRADUALLY DECREASE BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGHS ONLY TOPPING OFF IN THE 60S AND LOWS DIPPING INTO THE 40S. && .AVIATION /DISCUSSION FOR 100600Z TAF UPDATE/... ISSUED AT 1208 PM EDT FRI MAY 9 2014 SHORT TERM MODELS SHOWING VARIABILITY ABOUT RAIN/THUNDER DURING THE OVERNIGHT...BUT A COUPLE ARE SHOWING THE FRONT STALLING OUT AND RAIN OR POSSIBLY THUNDER ALONG AN EAST-WEST AREA THAT WOULD INCLUDE ALL SITES BUT KLAF. PUT A TEMPO SHOWER IN AT KHUF AND KIND AND PUT A PREVAILING SHOWER IN AT KBMG. GUIDANCE INDICATES SOME MVFR CEILINGS/VISIBILITIES WITH THIS SO INCLUDED THEM AS WELL. ANY RESTRICTIONS THAT DO DEVELOP SHOULD BE GONE BY AROUND 13Z AND THEN VFR FOR THE DAY. WINDS WILL DROP OFF OVER THE NEXT COUPLE OF HOURS AND THEN SHOULD REMAIN FAIRLY LIGHT THROUGH SATURDAY. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK/RYAN NEAR TERM...RYAN SHORT TERM...MK LONG TERM....TDUD AVIATION...CP/JP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
645 PM CDT SUN MAY 11 2014 .UPDATE... ISSUED AT 635 PM CDT SUN MAY 11 2014 DATA TRENDS THE PAST 3 HOURS NOW INDICATE THERE WILL BE A BREAK IN ACTIVITY DURING THE EVENING HOURS. THE CURRENT THUNDERSTORM COMPLEX IS SLOWLY MOVING INTO NORTHEAST ILLINOIS BUT BOUNDARIES LEFT OVER WILL ALLOW STORMS TO PERSIST OVER THE SOUTHERN PARTS OF THE AREA FOR THE NEXT SEVERAL HOURS. AN EFFECTIVE BOUNDARY IS EVIDENT ACROSS SOUTHERN IOWA WITH NO CELLULAR CLOUDS NORTH OF THE BOUNDARY AND DIURNAL CLOUDS ACROSS MISSOURI. THIS BOUNDARY MAY PROVIDE A FOCUS FOR ADDITIONAL ISOLATED TO SCATTERED STORMS THROUGH SUNSET. DATA STILL SUGGESTS THE STORMS IN NEBRASKA WILL EVOLVE INTO A NEW THUNDERSTORM COMPLEX ACROSS WESTERN IOWA THIS EVENING IN THE BETTER FORCING AND SLOWLY MOVE EASTWARD WITH ACTIVITY ENTERING THE NORTHWEST HALF OF THE AREA AFTER MIDNIGHT. && .SYNOPSIS... ISSUED AT 356 PM CDT SUN MAY 11 2014 12Z UA ANALYSIS HAS 850MB LOWS IN NORTHWEST MINNESOTA WITH A STRONG 850MB LOW IN WESTERN KANSAS. AN 850MB WARM FRONT RAN FROM THE KANSAS LOW INTO SOUTHERN IOWA. A STRONG LLJ RAN FROM THE GULF COAST INTO THE CENTRAL PLAINS. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON HAS CONVECTION ACROSS EASTERN IOWA AND NORTHERN ILLINOIS WITH NEW CONVECTION DEVELOPING IN THE PLAINS. 18Z SFC ANALYSIS HAS A WEAK LOW IN WESTERN WISCONSIN WITH A DEVELOPING WARM FRONT SOUTHEAST INTO CENTRAL LAKE MICHIGAN. AN IMPLIED LOW WAS IN SOUTHERN IOWA APPROACHING KOTM WITH ANOTHER LOW IN WESTERN KANSAS. A FRONTAL BOUNDARY RAN FROM THE KANSAS LOW INTO THE IOWA LOW NEAR KOTM WITH A WARM FRONT FROM NEAR KOTM NORTHEAST TO THE WISCONSIN/ILLINOIS BORDER. DEW POINTS SOUTH OF THE FRONT WERE IN THE 60S WITH 40S AND 50S IN THE NORTHERN PLAINS INTO THE GREAT LAKES NORTH OF THE FRONT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 356 PM CDT SUN MAY 11 2014 BOUNDARIES FROM THE NOCTURNAL THUNDERSTORM COMPLEX INITIATED A NEW STORM COMPLEX ALONG THE WARM FRONT IN SOUTHERN IOWA THIS MORNING. THIS NEW STORM COMPLEX MOVED EAST NORTHEAST AND IS SLOWLY DECAYING ACROSS THE AREA. HOWEVER...BOUNDARIES FROM THIS STORM ALONG WITH DIURNAL HEATING HAS INITIATED NEW DISCRETE STRONG TO SEVERE STORMS THAT WILL CONTINUE THROUGH LATE AFTERNOON. BASED ON SATELLITE...RADAR...AND RAP TRENDS...THERE MAY BE A BREAK IN STORM ACTIVITY THIS EVENING AS THE NEW SEVERE STORMS CONTINUE TO DEVELOP AND MOVE NORTHEAST WELL WEST OF THE AREA. AFTER MIDNIGHT THE STORMS OUT WEST WILL EVOLVE UPSCALE INTO ANOTHER NOCTURNAL THUNDERSTORM COMPLEX THAT WILL SLOWLY MOVE INTO THE NORTHWEST THIRD OF THE AREA. ISOLATED TO SCATTERED STORMS ARE VERY POSSIBLE AHEAD OF THIS STORM COMPLEX AS MOISTURE CONTINUES TO FEED INTO THE AREA. ON MONDAY THE BETTER RAIN CHANCES WILL BE OVER THE NORTHWEST HALF OF THE AREA DURING THE MORNING. DURING THE AFTERNOON...NEW CONVECTION IS EXPECTED TO DEVELOP AS ANOTHER DISTURBANCE ALOFT MOVES THROUGH THE AREA. BASED ON THE POSITION OF THE MAIN FEATURES AND OVERALL EXPECTED FORCING...SEVERE STORMS ARE POSSIBLE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 356 PM CDT SUN MAY 11 2014 MONDAY NIGHT THE MAIN COLD FRONT BEGINS MOVING THROUGH THE AREA. CONVECTION IS EXPECTED TO BE WIDESPREAD AND MAY EVOLVE INTO A BAND OF STRONG STORMS DURING THE EVENING HOURS. IF A BAND DOES FORM IT WILL SLOWLY MOVE EAST OVERNIGHT. ON TUESDAY...RAIN WILL END FROM WEST TO EAST DURING THE DAY WITH MOST OF THE AREA BEING DRY BY MID DAY. TEMPERATURES WILL BE WELL BELOW NORMAL. HIGH PRESSURE MOVING THROUGH THE MIDWEST TUESDAY NIGHT WILL RESULT IN DRY CONDITIONS WITH SEASONABLY COOL TEMPERATURES. ON WEDNESDAY THE NEXT STORM SYSTEM MOVES NORTHEAST FROM THE SOUTHERN PLAINS INTO THE OHIO VALLEY. THE TRENDS WITH THE MODELS HAVE BEEN TO SLOWLY PULL THE STORM SYSTEM TO THE NORTH AND WEST. WEDNESDAY NIGHT ON... THERE CONTINUES TO BE DIFFERENCES BETWEEN THE GLOBAL MODELS AS TO WHAT WILL OCCUR...BUT...ALL AGREE THAT TEMPERATURES WILL AVERAGE BELOW NORMAL WEDNESDAY NIGHT THROUGH SUNDAY. WEDNESDAY NIGHT/THURSDAY THE MODEL CONSENSUS HAS SLIGHT CHANCE TO CHANCE POPS AS THE NEXT SYSTEM MOVES UP THROUGH THE OHIO VALLEY. THE TREND IN THE MODELS HAS BEEN TO SLOWLY BRING THE STORM FURTHER TO THE NORTH AND WEST. THE MODEL CONSENSUS HAS MAINLY DRY CONDITIONS THURSDAY NIGHT AS THE STORM SYSTEM EXITS THE AREA. FRIDAY THROUGH SATURDAY THE MODEL CONSENSUS HAS MAINLY SLIGHT CHANCE POPS FRIDAY AND SATURDAY WITH MAINLY DRY CONDITIONS FRIDAY NIGHT. DISTURBANCES WILL CONTINUE TO ROTATE AROUND THE UPPER LOW OVER THE GREAT LAKES PRODUCING MAINLY DIURNAL SHOWERS. IF ENOUGH CLEARING CAN TAKE PLACE FRIDAY NIGHT AND WINDS REMAIN LIGHT...THERE MAY BE A POTENTIAL FOR FROST. DRY CONDITIONS SHOULD BE SEEN SATURDAY NIGHT AS HIGH PRESSURE MOVES THROUGH THE AREA. ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO CHANCE POPS FOR ROUGHLY THE WESTERN HALF OF THE AREA AS THE NEXT STORM SYSTEM MOVES EAST FROM THE PLAINS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 635 PM CDT SUN MAY 11 2014 VFR CONDITIONS WILL BE SEEN THROUGH 06Z/12 EXCEPT AROUND THE CONVECTION THAT MAY AFFECT KMLI/KBRL THROUGH 02Z/12. AFT 06Z/12 A THUNDERSTORM COMPLEX WILL DEVELOP IN WESTERN IOWA THAT SLOWLY MOVES EAST. THIS STORM COMPLEX SHOULD BEGIN ENTERING EASTERN IOWA PRIOR TO SUNRISE. VFR CONDITIONS SHOULD BE SEEN THROUGH SUNRISE WITH POSSIBLE MVFR CONDITIONS AS CONVECTION MOVES INTO EASTERN IOWA. AFT 12Z/12 BORDERLINE MVFR/VFR CONDITIONS ARE EXPECTED WITH SCATTERED TSRA. TSRA WILL DECAY/DISSIPATE MONDAY MORNING WITH NEW TSRA DEVELOPMENT AFT 18Z/12 WITH POSSIBLE MVFR CONDITIONS. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...08 SHORT TERM...08 LONG TERM...08 AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
103 PM CDT SAT MAY 10 2014 .SYNOPSIS... ISSUED AT 222 AM CDT SAT MAY 10 2014 00Z UPPER AIR ANALYSIS DEPICTED SHORTWAVE LIFTING NORTHEAST ACROSS WISCONSIN WITH WEAK RIDGING DEVELOPING ACROSS THE UPPER PLAINS. STRONG 130 KT JET ALSO ANALYZED COMING ONSHORE OVER CALIFORNIA. LATEST WV IMAGERY SHOWS SEVERAL OTHER WEAKER WAVES MOVING IN THE SEMI-ZONAL FLOW OVER THE PLAINS. THESE WAVES WERE RESPONSIBLE FOR THE INCREASING CLOUDS OVER THE CENTRAL CONUS. AT THE SURFACE...A RIDGE OF HIGH PRESSURE EXTENDED FROM FREEPORT ILLINOIS NORTHWEST INTO NORTH DAKOTA. TEMPERATURES AS OF 2AM WERE IN THE LOWER 40S TO LOWER 50S WITH THE LOWEST READINGS SEEN IN THE WAPSI RIVER VALLEY. DEWPOINTS WERE IN THE UPPER 30S TO MIDDLE 40S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 222 AM CDT SAT MAY 10 2014 FORECAST FOCUS ON PCPN CHANCES THIS EVENING AND INTO SUNDAY WITH A CHANCE OF A FEW STRONG TO SEVERE STORMS MAINLY IN THE FAR SOUTH PORTIONS OF THE CWA TODAY...SURFACE RIDGE AXIS TO MOVE EAST OVER THE GREAT LAKES TODAY RESULTING IN A S-SE RETURN FLOW. THIS COMBINED WITH SLOWLY WARMING TEMPERATURES ALOFT WILL ALLOW FOR A WARMER DAY THAN COMPARED TO YESTERDAY. DEEP MIXING...DEWPOINTS IN THE 40S...AND AT LEAST PARTLY SUNNY SKIES WILL BOOST TEMPERATURES WELL INTO THE 70S. A FEW LOCATIONS IN THE FAR SOUTH MAY EVEN APPROACH 80 DEGREES. SURFACE LOW TO DEVELOP ON LEE SIDE OF ROCKIES AND MOVE INTO WESTERN KANSAS BY THIS EVENING. LATEST HI-RES MODELS AND RAP TRENDS SHOW CONVECTION ACROSS NORTHWEST MISSOURI AROUND 21Z ALONG AND NORTH OF A WARM FRONT TODAY AND PROPAGATE EAST. SOME OF THESE STORMS MAY BECOME SEVERE DUE TO A FAVORABLE ENVIRONMENT WITH STEEP LOW LEVEL LAPSE RATES...MUCAPES OVER 2000 J/KG...AND 0-6KM SHEAR VALES IN EXCESS OF 50 KTS. AMOUNT OF DAYTIME HEATING WILL BE KEY AS TO WHEN STORMS INITIATE. LOW FREEZING LEVELS SUGGEST THAT THE PRIMARY THREAT WILL BE LARGE HAIL AS NOTED IN SPC DAY 1 OUTLOOK. LOW LEVEL SHEAR ALTHOUGH MARGINAL MAY BE ENOUGH FOR AN ISOLATED TORNADO THREAT AS WELL DUE TO THE CLOSE PROXIMITY OF THE WARM FRONT. THIS APPEARS AT THIS TIME A BETTER POSSIBLY JUST SOUTH AND WEST OF THE CWA. TONIGHT...FORCING PROGS AND TIME HEIGHT SECTIONS SHOW THE BEST FORCING AND LOW LEVEL MOISTURE ARRIVING AFTER 00Z SUN ESPECIALLY ACROSS THE SOUTH AS WARM FRONT IS DRAPED OVER NORTHERN MISSOURI INTO SOUTHERN ILLINOIS. INCREASING LLJ OVERNIGHT SHOULD ALLOW STORMS TO CONTINUE INTO THE NIGHT. QPF AMOUNTS WILL BE LESS THAN A QUARTER OF AN INCH BY 12Z SUNDAY ACROSS MOST AREAS EXCEPT FOR THOSE THAT RECEIVE A THUNDERSTORM. CLOUDS AND WAA ALOFT WILL ALLOW FOR A MILD NIGHT...WITH LOWS IN THE MIDDLE 50S NORTH TO THE LOWER 60S IN THE SOUTH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 222 AM CDT SAT MAY 10 2014 A DEEP UPPER TROF DEVELOPING OVER THE WESTERN U.S. WILL MOVE SLOWLY EAST PUSHING A COLD FRONT THROUGH THE REGION MONDAY AND MONDAY NIGHT. THE UPPER TROF AND COLD FRONT WILL KEEP THUNDERSTORM CHANCES OVER THE FORECAST AREA THROUGH MONDAY NIGHT. THE LONG RANGE MODELS ARE IN BETTER AGREEMENT ON THE 00Z RUN WITH THE TIMING OF THE SURFACE FRONT THROUGH THE FORECAST AREA...ALTHOUGH THE 00Z ECMWF CONTINUES TO LAG THE GFS/NAM TIMING. ALL MODEL SOLUTIONS ARE POINTING TO A POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT FOR THE MIDWEST SUNDAY AND SUNDAY NIGHT ALONG WITH A THREAT OF LOCALLY HEAVY RAINS. BY SUNDAY MORNING THE UPPER TROF IS PROGGED TO BE LOCATED OVER THE ROCKIES WITH A COLD FRONT FROM WESTERN KANSAS THROUGH NORTHWEST IOWA AND A WARM FRONT NEAR THE IA/MO BORDER. THE COLD FRONT WILL MOVE SLOWLY EAST AS AT LEAST A COUPLE OF WAVES MOVE NORTHEAST ALONG THE FRONT. THESE WAVES WILL KEEP THE FRONT FROM MOVING MUCH SUNDAY AND SUNDAY NIGHT...THEN THE BOUNDARY SHOULD PUSH EAST MONDAY AND EXIT THE FORECAST AREA MONDAY NIGHT. WARM MOIST AIR WILL SPREAD NORTH AHEAD OF THE FRONT BRINGING MORE WARM AND HUMID CONDITIONS TO THE REGION SUNDAY AND MONDAY. THE INFLUX OF THE WARM MOIST AIR WILL PROVIDE A GOOD SUPPLY OF UNSTABLE AIR TO FUEL THUNDERSTORMS ESPECIALLY SUNDAY AFTERNOON AND SUNDAY NIGHT. IT APPEARS THAT SOME OF THE STORMS DURING THIS PERIOD WILL BE SEVERE WITH THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS AND TORNADOES. THE TORNADIC THREAT WILL BE THE GREATEST NEAR A WARM FRONT THAT IS EXPECTED TO EXTEND THROUGH EAST CENTRAL OR NORTHEAST IOWA INTO NORTHERN ILLINOIS OR SOUTHERN WI BY SUNDAY EVENING. A HEAVY RAIN THREAT WILL ALSO EXIST SUNDAY AND SUNDAY NIGHT WITH PW/S EXPECTED TO BE AROUND 1.5 TO 1.75 INCHES. THE COLD FRONT TO THE WEST AND THE WARM FRONT WILL PROVIDE THE FOCUS FOR THE HEAVIER RAINFALL. LATEST WPC GUIDANCE SHOWS A SWATH OF 2 TO 4 INCHES OF RAIN SUNDAY AND SUNDAY NIGHT FROM NORTHEAST THROUGH SOUTHWEST IOWA. WHILE THE AMOUNTS LOOK REASONABLE GIVEN THE MOIST ENVIRONMENT THERE IS STILL SOME UNCERTAINTY ON THE LOCATION OF THE SURFACE BOUNDARIES...SO KEPT THE FORECAST QPF LOWER THAN WPC. THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE FORECAST AREA MONDAY OR MONDAY EVENING. THIS WILL KEEP THE CWFA IN THE UNSEASONABLY WARM AND MOIST AIRMASS FOR MOST IF NOT ALL OF MONDAY. THERE WILL ALSO BE A CONTINUED THREAT OF SEVERE THUNDERSTORMS UNTIL THE COLD FRONT MOVES THROUGH. FOR THE REST OF THE WEEK THE MODEL SOLUTIONS DIVERGE WITH RESPECT TO THE UPPER TROF. THE ECMWF CONTINUES TO FAVOR A SLOWER EASTWARD PROGRESSION THAN THE GFS. WITH THE SLOWER ECM PROGS WILL HAVE TO KEEP A CHANCE OF SHOWERS GOING MOST DAYS FROM TUESDAY THROUGH FRIDAY. AFTER THE COLD FROPA MONDAY NIGHT TEMPERATURES WILL RETURN TO BELOW NORMAL FOR THE REST OF THE WEEK. HIGHS SHOULD BE IN THE UPPER 50S TO MID 60S WITH LOWS MAINLY IN THE 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1249 PM CDT SAT MAY 10 2014 MAINLY VFR CONDITIONS EXPECTED THROUGH SUNDAY AM. FEW HIGH BASED LIGHT SHOWERS WILL MOVE ACROSS NORTHEAST IA EARLY THIS AFTERNOON. ADDITIONAL SCATTERED SHOWERS AND STORMS EXPECTED TO DEVELOP MID TO LATE AFTERNOON INTO EARLY EVENING TO W/SW OF CWA... AND ANTICIPATE BULK OF STORMS WITH POTENTIAL FOR STRONG TO SEVERE STORMS TO SLIDE E/SE SOUTH OF TERMINALS NORTH OF WARM FRONT ALONG MOISTURE GRADIENT. STILL EXPECT AT LEAST SOME SCATTERED SHOWERS AND POSSIBLY FEW STORMS AROUND THE AREA THIS EVENING EXITING OVERNIGHT WITH PASSAGE OF UPPER LEVEL DISTURBANCE. THEN... WILL HAVE POTENTIAL FOR ELEVATED SCATTERED SHOWERS AND STORMS DEVELOPING LATE TONIGHT FAR SOUTHEAST IA...NORTHEAST MO INTO WEST CENTRAL IL NORTH OF WARM FRONT. THIS ACTIVITY MAY CONTINUE TO DEVELOP AND/OR LIFT NORTHWARD THROUGH EASTERN IA SUNDAY AM. WINDS WILL REMAIN SOUTHERLY AROUND 10 KTS THROUGH THE PERIOD AND OCCASIONALLY GUST AROUND 20-25 KTS THIS AFTERNOON AND AGAIN MID TO LATE SUNDAY AM. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...GROSS SHORT TERM...GROSS LONG TERM...DLF AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
651 AM CDT SAT MAY 10 2014 .SYNOPSIS... ISSUED AT 222 AM CDT SAT MAY 10 2014 00Z UPPER AIR ANALYSIS DEPICTED SHORTWAVE LIFTING NORTHEAST ACROSS WISCONSIN WITH WEAK RIDGING DEVELOPING ACROSS THE UPPER PLAINS. STRONG 130 KT JET ALSO ANALYZED COMING ONSHORE OVER CALIFORNIA. LATEST WV IMAGERY SHOWS SEVERAL OTHER WEAKER WAVES MOVING IN THE SEMI-ZONAL FLOW OVER THE PLAINS. THESE WAVES WERE RESPONSIBLE FOR THE INCREASING CLOUDS OVER THE CENTRAL CONUS. AT THE SURFACE...A RIDGE OF HIGH PRESSURE EXTENDED FROM FREEPORT ILLINOIS NORTHWEST INTO NORTH DAKOTA. TEMPERATURES AS OF 2AM WERE IN THE LOWER 40S TO LOWER 50S WITH THE LOWEST READINGS SEEN IN THE WAPSI RIVER VALLEY. DEWPOINTS WERE IN THE UPPER 30S TO MIDDLE 40S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 222 AM CDT SAT MAY 10 2014 FORECAST FOCUS ON PCPN CHANCES THIS EVENING AND INTO SUNDAY WITH A CHANCE OF A FEW STRONG TO SEVERE STORMS MAINLY IN THE FAR SOUTH PORTIONS OF THE CWA TODAY...SURFACE RIDGE AXIS TO MOVE EAST OVER THE GREAT LAKES TODAY RESULTING IN A S-SE RETURN FLOW. THIS COMBINED WITH SLOWLY WARMING TEMPERATURES ALOFT WILL ALLOW FOR A WARMER DAY THAN COMPARED TO YESTERDAY. DEEP MIXING...DEWPOINTS IN THE 40S...AND AT LEAST PARTLY SUNNY SKIES WILL BOOST TEMPERATURES WELL INTO THE 70S. A FEW LOCATIONS IN THE FAR SOUTH MAY EVEN APPROACH 80 DEGREES. SURFACE LOW TO DEVELOP ON LEE SIDE OF ROCKIES AND MOVE INTO WESTERN KANSAS BY THIS EVENING. LATEST HI-RES MODELS AND RAP TRENDS SHOW CONVECTION ACROSS NORTHWEST MISSOURI AROUND 21Z ALONG AND NORTH OF A WARM FRONT TODAY AND PROPAGATE EAST. SOME OF THESE STORMS MAY BECOME SEVERE DUE TO A FAVORABLE ENVIRONMENT WITH STEEP LOW LEVEL LAPSE RATES...MUCAPES OVER 2000 J/KG...AND 0-6KM SHEAR VALES IN EXCESS OF 50 KTS. AMOUNT OF DAYTIME HEATING WILL BE KEY AS TO WHEN STORMS INITIATE. LOW FREEZING LEVELS SUGGEST THAT THE PRIMARY THREAT WILL BE LARGE HAIL AS NOTED IN SPC DAY 1 OUTLOOK. LOW LEVEL SHEAR ALTHOUGH MARGINAL MAY BE ENOUGH FOR AN ISOLATED TORNADO THREAT AS WELL DUE TO THE CLOSE PROXIMITY OF THE WARM FRONT. THIS APPEARS AT THIS TIME A BETTER POSSIBLY JUST SOUTH AND WEST OF THE CWA. TONIGHT...FORCING PROGS AND TIME HEIGHT SECTIONS SHOW THE BEST FORCING AND LOW LEVEL MOISTURE ARRIVING AFTER 00Z SUN ESPECIALLY ACROSS THE SOUTH AS WARM FRONT IS DRAPED OVER NORTHERN MISSOURI INTO SOUTHERN ILLINOIS. INCREASING LLJ OVERNIGHT SHOULD ALLOW STORMS TO CONTINUE INTO THE NIGHT. QPF AMOUNTS WILL BE LESS THAN A QUARTER OF AN INCH BY 12Z SUNDAY ACROSS MOST AREAS EXCEPT FOR THOSE THAT RECEIVE A THUNDERSTORM. CLOUDS AND WAA ALOFT WILL ALLOW FOR A MILD NIGHT...WITH LOWS IN THE MIDDLE 50S NORTH TO THE LOWER 60S IN THE SOUTH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 222 AM CDT SAT MAY 10 2014 A DEEP UPPER TROF DEVELOPING OVER THE WESTERN U.S. WILL MOVE SLOWLY EAST PUSHING A COLD FRONT THROUGH THE REGION MONDAY AND MONDAY NIGHT. THE UPPER TROF AND COLD FRONT WILL KEEP THUNDERSTORM CHANCES OVER THE FORECAST AREA THROUGH MONDAY NIGHT. THE LONG RANGE MODELS ARE IN BETTER AGREEMENT ON THE 00Z RUN WITH THE TIMING OF THE SURFACE FRONT THROUGH THE FORECAST AREA...ALTHOUGH THE 00Z ECMWF CONTINUES TO LAG THE GFS/NAM TIMING. ALL MODEL SOLUTIONS ARE POINTING TO A POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT FOR THE MIDWEST SUNDAY AND SUNDAY NIGHT ALONG WITH A THREAT OF LOCALLY HEAVY RAINS. BY SUNDAY MORNING THE UPPER TROF IS PROGGED TO BE LOCATED OVER THE ROCKIES WITH A COLD FRONT FROM WESTERN KANSAS THROUGH NORTHWEST IOWA AND A WARM FRONT NEAR THE IA/MO BORDER. THE COLD FRONT WILL MOVE SLOWLY EAST AS AT LEAST A COUPLE OF WAVES MOVE NORTHEAST ALONG THE FRONT. THESE WAVES WILL KEEP THE FRONT FROM MOVING MUCH SUNDAY AND SUNDAY NIGHT...THEN THE BOUNDARY SHOULD PUSH EAST MONDAY AND EXIT THE FORECAST AREA MONDAY NIGHT. WARM MOIST AIR WILL SPREAD NORTH AHEAD OF THE FRONT BRINGING MORE WARM AND HUMID CONDITIONS TO THE REGION SUNDAY AND MONDAY. THE INFLUX OF THE WARM MOIST AIR WILL PROVIDE A GOOD SUPPLY OF UNSTABLE AIR TO FUEL THUNDERSTORMS ESPECIALLY SUNDAY AFTERNOON AND SUNDAY NIGHT. IT APPEARS THAT SOME OF THE STORMS DURING THIS PERIOD WILL BE SEVERE WITH THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS AND TORNADOES. THE TORNADIC THREAT WILL BE THE GREATEST NEAR A WARM FRONT THAT IS EXPECTED TO EXTEND THROUGH EAST CENTRAL OR NORTHEAST IOWA INTO NORTHERN ILLINOIS OR SOUTHERN WI BY SUNDAY EVENING. A HEAVY RAIN THREAT WILL ALSO EXIST SUNDAY AND SUNDAY NIGHT WITH PW/S EXPECTED TO BE AROUND 1.5 TO 1.75 INCHES. THE COLD FRONT TO THE WEST AND THE WARM FRONT WILL PROVIDE THE FOCUS FOR THE HEAVIER RAINFALL. LATEST WPC GUIDANCE SHOWS A SWATH OF 2 TO 4 INCHES OF RAIN SUNDAY AND SUNDAY NIGHT FROM NORTHEAST THROUGH SOUTHWEST IOWA. WHILE THE AMOUNTS LOOK REASONABLE GIVEN THE MOIST ENVIRONMENT THERE IS STILL SOME UNCERTAINTY ON THE LOCATION OF THE SURFACE BOUNDARIES...SO KEPT THE FORECAST QPF LOWER THAN WPC. THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE FORECAST AREA MONDAY OR MONDAY EVENING. THIS WILL KEEP THE CWFA IN THE UNSEASONABLY WARM AND MOIST AIRMASS FOR MOST IF NOT ALL OF MONDAY. THERE WILL ALSO BE A CONTINUED THREAT OF SEVERE THUNDERSTORMS UNTIL THE COLD FRONT MOVES THROUGH. FOR THE REST OF THE WEEK THE MODEL SOLUTIONS DIVERGE WITH RESPECT TO THE UPPER TROF. THE ECMWF CONTINUES TO FAVOR A SLOWER EASTWARD PROGRESSION THAN THE GFS. WITH THE SLOWER ECM PROGS WILL HAVE TO KEEP A CHANCE OF SHOWERS GOING MOST DAYS FROM TUESDAY THROUGH FRIDAY. AFTER THE COLD FROPA MONDAY NIGHT TEMPERATURES WILL RETURN TO BELOW NORMAL FOR THE REST OF THE WEEK. HIGHS SHOULD BE IN THE UPPER 50S TO MID 60S WITH LOWS MAINLY IN THE 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 631 AM CDT SAT MAY 10 2014 VFR CONDITIONS EXPECTED THROUGH THE TAF CYCLE. SURFACE RIDGE TO CONTINUE TO MOVE EAST THIS MORNING RESULTING IN S-SE WINDS DEVELOPING. HIGH BASED STORMS TO FORM DURING THE LATE AFTERNOON IN NORTHWEST MISSOURI AND PUSH EAST AFFECTING THE TERMINALS MAINLY DURING THE LATE EVENING HOURS. THUNDERSTORM POTENTIAL GREATEST IN NORTHERN MISSOURI AND SOUTHEAST IOWA AND HAVE INCLUDED TEMPO GROUP AT THE BRL TERMINAL. ELEVATED STORMS WILL KEEP CIGS/VSBYS GENERALLY VFR THROUGH 12Z SUNDAY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...GROSS SHORT TERM...GROSS LONG TERM...DLF AVIATION...GROSS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
315 AM CDT SAT MAY 10 2014 .SYNOPSIS... ISSUED AT 222 AM CDT SAT MAY 10 2014 00Z UPPER AIR ANALYSIS DEPICTED SHORTWAVE LIFTING NORTHEAST ACROSS WISCONSIN WITH WEAK RIDGING DEVELOPING ACROSS THE UPPER PLAINS. STRONG 130 KT JET ALSO ANALYZED COMING ONSHORE OVER CALIFORNIA. LATEST WV IMAGERY SHOWS SEVERAL OTHER WEAKER WAVES MOVING IN THE SEMI-ZONAL FLOW OVER THE PLAINS. THESE WAVES WERE RESPONSIBLE FOR THE INCREASING CLOUDS OVER THE CENTRAL CONUS. AT THE SURFACE...A RIDGE OF HIGH PRESSURE EXTENDED FROM FREEPORT ILLINOIS NORTHWEST INTO NORTH DAKOTA. TEMPERATURES AS OF 2AM WERE IN THE LOWER 40S TO LOWER 50S WITH THE LOWEST READINGS SEEN IN THE WAPSI RIVER VALLEY. DEWPOINTS WERE IN THE UPPER 30S TO MIDDLE 40S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 222 AM CDT SAT MAY 10 2014 FORECAST FOCUS ON PCPN CHANCES THIS EVENING AND INTO SUNDAY WITH A CHANCE OF A FEW STRONG TO SEVERE STORMS MAINLY IN THE FAR SOUTH PORTIONS OF THE CWA TODAY...SURFACE RIDGE AXIS TO MOVE EAST OVER THE GREAT LAKES TODAY RESULTING IN A S-SE RETURN FLOW. THIS COMBINED WITH SLOWLY WARMING TEMPERATURES ALOFT WILL ALLOW FOR A WARMER DAY THAN COMPARED TO YESTERDAY. DEEP MIXING...DEWPOINTS IN THE 40S...AND AT LEAST PARTLY SUNNY SKIES WILL BOOST TEMPERATURES WELL INTO THE 70S. A FEW LOCATIONS IN THE FAR SOUTH MAY EVEN APPROACH 80 DEGREES. SURFACE LOW TO DEVELOP ON LEE SIDE OF ROCKIES AND MOVE INTO WESTERN KANSAS BY THIS EVENING. LATEST HI-RES MODELS AND RAP TRENDS SHOW CONVECTION ACROSS NORTHWEST MISSOURI AROUND 21Z ALONG AND NORTH OF A WARM FRONT TODAY AND PROPAGATE EAST. SOME OF THESE STORMS MAY BECOME SEVERE DUE TO A FAVORABLE ENVIRONMENT WITH STEEP LOW LEVEL LAPSE RATES...MUCAPES OVER 2000 J/KG...AND 0-6KM SHEAR VALES IN EXCESS OF 50 KTS. AMOUNT OF DAYTIME HEATING WILL BE KEY AS TO WHEN STORMS INITIATE. LOW FREEZING LEVELS SUGGEST THAT THE PRIMARY THREAT WILL BE LARGE HAIL AS NOTED IN SPC DAY 1 OUTLOOK. LOW LEVEL SHEAR ALTHOUGH MARGINAL MAY BE ENOUGH FOR AN ISOLATED TORNADO THREAT AS WELL DUE TO THE CLOSE PROXIMITY OF THE WARM FRONT. THIS APPEARS AT THIS TIME A BETTER POSSIBLY JUST SOUTH AND WEST OF THE CWA. TONIGHT...FORCING PROGS AND TIME HEIGHT SECTIONS SHOW THE BEST FORCING AND LOW LEVEL MOISTURE ARRIVING AFTER 00Z SUN ESPECIALLY ACROSS THE SOUTH AS WARM FRONT IS DRAPED OVER NORTHERN MISSOURI INTO SOUTHERN ILLINOIS. INCREASING LLJ OVERNIGHT SHOULD ALLOW STORMS TO CONTINUE INTO THE NIGHT. QPF AMOUNTS WILL BE LESS THAN A QUARTER OF AN INCH BY 12Z SUNDAY ACROSS MOST AREAS EXCEPT FOR THOSE THAT RECEIVE A THUNDERSTORM. CLOUDS AND WAA ALOFT WILL ALLOW FOR A MILD NIGHT...WITH LOWS IN THE MIDDLE 50S NORTH TO THE LOWER 60S IN THE SOUTH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 222 AM CDT SAT MAY 10 2014 A DEEP UPPER TROF DEVELOPING OVER THE WESTERN U.S. WILL MOVE SLOWLY EAST PUSHING A COLD FRONT THROUGH THE REGION MONDAY AND MONDAY NIGHT. THE UPPER TROF AND COLD FRONT WILL KEEP THUNDERSTORM CHANCES OVER THE FORECAST AREA THROUGH MONDAY NIGHT. THE LONG RANGE MODELS ARE IN BETTER AGREEMENT ON THE 00Z RUN WITH THE TIMING OF THE SURFACE FRONT THROUGH THE FORECAST AREA...ALTHOUGH THE 00Z ECMWF CONTINUES TO LAG THE GFS/NAM TIMING. ALL MODEL SOLUTIONS ARE POINTING TO A POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT FOR THE MIDWEST SUNDAY AND SUNDAY NIGHT ALONG WITH A THREAT OF LOCALLY HEAVY RAINS. BY SUNDAY MORNING THE UPPER TROF IS PROGGED TO BE LOCATED OVER THE ROCKIES WITH A COLD FRONT FROM WESTERN KANSAS THROUGH NORTHWEST IOWA AND A WARM FRONT NEAR THE IA/MO BORDER. THE COLD FRONT WILL MOVE SLOWLY EAST AS AT LEAST A COUPLE OF WAVES MOVE NORTHEAST ALONG THE FRONT. THESE WAVES WILL KEEP THE FRONT FROM MOVING MUCH SUNDAY AND SUNDAY NIGHT...THEN THE BOUNDARY SHOULD PUSH EAST MONDAY AND EXIT THE FORECAST AREA MONDAY NIGHT. WARM MOIST AIR WILL SPREAD NORTH AHEAD OF THE FRONT BRINGING MORE WARM AND HUMID CONDITIONS TO THE REGION SUNDAY AND MONDAY. THE INFLUX OF THE WARM MOIST AIR WILL PROVIDE A GOOD SUPPLY OF UNSTABLE AIR TO FUEL THUNDERSTORMS ESPECIALLY SUNDAY AFTERNOON AND SUNDAY NIGHT. IT APPEARS THAT SOME OF THE STORMS DURING THIS PERIOD WILL BE SEVERE WITH THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS AND TORNADOES. THE TORNADIC THREAT WILL BE THE GREATEST NEAR A WARM FRONT THAT IS EXPECTED TO EXTEND THROUGH EAST CENTRAL OR NORTHEAST IOWA INTO NORTHERN ILLINOIS OR SOUTHERN WI BY SUNDAY EVENING. A HEAVY RAIN THREAT WILL ALSO EXIST SUNDAY AND SUNDAY NIGHT WITH PW/S EXPECTED TO BE AROUND 1.5 TO 1.75 INCHES. THE COLD FRONT TO THE WEST AND THE WARM FRONT WILL PROVIDE THE FOCUS FOR THE HEAVIER RAINFALL. LATEST WPC GUIDANCE SHOWS A SWATH OF 2 TO 4 INCHES OF RAIN SUNDAY AND SUNDAY NIGHT FROM NORTHEAST THROUGH SOUTHWEST IOWA. WHILE THE AMOUNTS LOOK REASONABLE GIVEN THE MOIST ENVIRONMENT THERE IS STILL SOME UNCERTAINTY ON THE LOCATION OF THE SURFACE BOUNDARIES...SO KEPT THE FORECAST QPF LOWER THAN WPC. THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE FORECAST AREA MONDAY OR MONDAY EVENING. THIS WILL KEEP THE CWFA IN THE UNSEASONABLY WARM AND MOIST AIRMASS FOR MOST IF NOT ALL OF MONDAY. THERE WILL ALSO BE A CONTINUED THREAT OF SEVERE THUNDERSTORMS UNTIL THE COLD FRONT MOVES THROUGH. FOR THE REST OF THE WEEK THE MODEL SOLUTIONS DIVERGE WITH RESPECT TO THE UPPER TROF. THE ECMWF CONTINUES TO FAVOR A SLOWER EASTWARD PROGRESSION THAN THE GFS. WITH THE SLOWER ECM PROGS WILL HAVE TO KEEP A CHANCE OF SHOWERS GOING MOST DAYS FROM TUESDAY THROUGH FRIDAY. AFTER THE COLD FROPA MONDAY NIGHT TEMPERATURES WILL RETURN TO BELOW NORMAL FOR THE REST OF THE WEEK. HIGHS SHOULD BE IN THE UPPER 50S TO MID 60S WITH LOWS MAINLY IN THE 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1130 PM CDT FRI MAY 9 2014 SFC RIDGE CONTINUES TO MIGRATE EASTWARD ACRS THE REGION... MAINTAINING VFR CONDITIONS THROUGH SAT AFTERNOON. LIGHT AND VARIABLE WINDS ACRS THE AREA OVERNIGHT...WILL BECOME SOUTHERLY 10-15 KTS BEHIND PASSING RIDGE ON SAT. HIGH CLOUDS TO INCREASE AS SFC WINDS BACK MORE SOUTHEASTERLY BY LATE SAT AFTERNOON AND EARLY EVENING. ELEVATED PLUME OF WARM AIR ADVECTION MAY TOUCH OFF A FEW HIGH BASED SHOWERS AND THUNDERSTORMS BY MID SAT EVENING ACRS CENTRAL IA...WITH A CHANCE THAT SOME OF THESE MAKE IT FAR ENOUGH TO THE EAST TO GET IN THE VCNTY OF CID...DBQ AND POSSIBLY BRL FROM 03Z-06Z SUNDAY. WITH THE ELEVATED NATURE OF THESE SHOWERS/STORMS... CIGS STILL MAY REMAIN VFR THROUGH THE END OF THE TAF PERIOD. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...GROSS SHORT TERM...GROSS LONG TERM...DLF AVIATION...12
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1010 PM CDT Sun May 11 2014 ...UPDATE TO SYNOPSIS... .SYNOPSIS... ISSUED AT 1007 PM CDT SUN MAY 11 2014 Water vapor imagery and 00Z upper air analysis indicate a strong closed off upper level low shifting eastward across the Four Corners Region. A +70kt upper level jet is lifting northeast across western Kansas. Near the surface, a strong cold front extending from northeastern Kansas southwest into the Oklahoma panhandle, is pushing southeast across central Kansas. Much colder and drier air is spilling southward into western Kansas with surface dewpoints dropping mainly into the 40s(F) with a few 30s(F) out near the Colorado border. && .SHORT TERM...(This evening through Monday) ISSUED AT 254 PM CDT SUN MAY 11 2014 Abbreviated AFD due to ongoing warning operations. From my mesoscale discussion at 1:53 PM... (Convection already has developed by the same mesoscale assessments still applies) Special 18Z KDDC raob shows just a little bit of CIN remaining. Won`t be long before convection develops. Visible satellite imagery shows increasing cumulus along the dryline/front. HRRR indicates thunderstorms developing along the Highway 283 corridor in the 3-4 pm time range. Right moving Bunkers shows propagation vectors northeasterly at 45 kt. Initial threat will be large hail (up to 20! on the LHP using NAM thermodynamic and kinematic variables) and damaging outflow winds. There is an small window of tornadic opportunity between 7 and 9 pm as low level winds back across central/south central-Kansas but all the big wedge/strong tornadoes should remain across Nebraska/Iowa with just small spin ups/weak tornadoes in our area, if possible. Convection will depart the area tonight. Some light showers will be possible on the backside of the departing wave. It will be windy post frontal through tomorrow. Right now conditions look borderline for wind advisory criteria. .LONG TERM...(Monday night through Sunday) ISSUED AT 122 PM CDT SUN MAY 11 2014 An upper level longwave trough will be moving across the Plains on Tuesday but should be dry with the moisture pushed east of the area. Colder temperatures will accompany this trough with overnight lows on Monday night into the mid 30s and highs on Tuesday in the low to mid 60s. Strong northwest winds will mix down to the surface with winds of 15 to 30 mph and partly cloudy skies. For Wednesday into Thursday, dry northwesterly upper level flow will follow with highs slowly warming into the upper 60s and 70s. Wednesday morning may be the coldest morning with light winds and lows in the low to mid 30s. For Friday and Saturday, a few showers and thunderstorms may form as as some upper air disturbances in northwest flow aloft interact with increasing upslope moisture. Lows will be in the 40s and highs around 70 to 75. On Sunday, of next week, upper level ridging is forecast with dry and warmer temps around 80. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 649 PM CDT SUN MAY 11 2014 The severe weather threat will be diminishing early this evening for DDC and HYS terminals. Winds will become strong north- northwest this evening as the cold front moves through. Ceiling will fall to 2000 to 3000 feet behind the front with MVFR conditions expected through the night into tomorrow morning. VFR will resume by around midday to early afternoon, but northwest winds sustained around 20 knots will continue. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 56 35 63 / 20 10 0 0 GCK 42 53 34 62 / 20 20 0 0 EHA 42 55 34 61 / 10 10 0 10 LBL 44 58 34 62 / 10 10 0 10 HYS 46 53 35 63 / 80 30 0 0 P28 56 63 40 66 / 80 20 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY until 1 AM CDT /Midnight MDT/ Monday FOR KSZ030- 031-043>046-061>066-074>081-084>090. && $$ SYNOPSIS...JJohnson SHORT TERM...Sugden LONG TERM...Kruse AVIATION...Umscheid
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
653 PM CDT Sun May 11 2014 ...Updated aviation section... .SHORT TERM...(This evening through Monday) ISSUED AT 254 PM CDT SUN MAY 11 2014 Abbreviated AFD due to ongoing warning operations. From my mesoscale discussion at 1:53 PM... (Convection already has developed by the same mesoscale assessments still applies) Special 18Z KDDC raob shows just a little bit of CIN remaining. Won`t be long before convection develops. Visible satellite imagery shows increasing cumulus along the dryline/front. HRRR indicates thunderstorms developing along the Highway 283 corridor in the 3-4 pm time range. Right moving Bunkers shows propagation vectors northeasterly at 45 kt. Initial threat will be large hail (up to 20! on the LHP using NAM thermodynamic and kinematic variables) and damaging outflow winds. There is an small window of tornadic opportunity between 7 and 9 pm as low level winds back across central/south central-Kansas but all the big wedge/strong tornadoes should remain across Nebraska/Iowa with just small spin ups/weak tornadoes in our area, if possible. Convection will depart the area tonight. Some light showers will be possible on the backside of the departing wave. It will be windy post frontal through tomorrow. Right now conditions look borderline for wind advisory criteria. .LONG TERM...(Monday night through Sunday) ISSUED AT 122 PM CDT SUN MAY 11 2014 An upper level longwave trough will be moving across the Plains on Tuesday but should be dry with the moisture pushed east of the area. Colder temperatures will accompany this trough with overnight lows on Monday night into the mid 30s and highs on Tuesday in the low to mid 60s. Strong northwest winds will mix down to the surface with winds of 15 to 30 mph and partly cloudy skies. For Wednesday into Thursday, dry northwesterly upper level flow will follow with highs slowly warming into the upper 60s and 70s. Wednesday morning may be the coldest morning with light winds and lows in the low to mid 30s. For Friday and Saturday, a few showers and thunderstorms may form as as some upper air disturbances in northwest flow aloft interact with increasing upslope moisture. Lows will be in the 40s and highs around 70 to 75. On Sunday, of next week, upper level ridging is forecast with dry and warmer temps around 80. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 649 PM CDT SUN MAY 11 2014 The severe weather threat will be diminishing early this evening for DDC and HYS terminals. Winds will become strong north- northwest this evening as the cold front moves through. Ceiling will fall to 2000 to 3000 feet behind the front with MVFR conditions expected through the night into tomorrow morning. VFR will resume by around midday to early afternoon, but northwest winds sustained around 20 knots will continue. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 56 35 63 / 20 10 0 0 GCK 42 53 34 62 / 20 20 0 0 EHA 42 55 34 61 / 10 10 0 10 LBL 44 58 34 62 / 10 10 0 10 HYS 46 53 35 63 / 80 30 0 0 P28 56 63 40 66 / 80 20 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY until 8 PM CDT this evening FOR KSZ046-065-066- 078>081-088>090. RED FLAG WARNING until 9 PM CDT this evening FOR KSZ074>076- 084>086. && $$ SHORT TERM...Sugden LONG TERM...Kruse AVIATION...Umscheid
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CDT Sat May 10 2014 ...UPDATE TO AVIATION... .SYNOPSIS... ISSUED AT 955 PM CDT FRI MAY 9 2014 Water vapor imagery and 00Z upper air analysis indicate a zonal flow aloft prevailing across the Western High Plains. Meanwhile, an upper level trough is pushing southeast across the Pacific Northwest. Near the surface...a weak lee side trough of low pressure is set up along the Colorado and Kansas border. Drier air remains in place across the area with surface dewpoints in the 30s(F) across central and much of southwest Kansas. && .SHORT TERM...(This evening through Saturday) ISSUED AT 313 PM CDT FRI MAY 9 2014 The upper level jet is progged to continue moving east this afternoon with western Kansas coming under the left exit region of upper jet this evening. Model soundings from the NAM and RUC13 show fairly deep mixing with some small elevated CAPE developing along the Colorado border by late this afternoon. The last few runs of the HRRR have been consistent in showing isolated showers developing along the Colorado border and moving into west central and southwest Kansas for a few hours this evening. Will add this to the grids for this evening. As the weak shortwave moves over late tonight, another weak surge of high pressure will push into southwest Kansas late tonight and early Saturday. Overnight lows will drop into the mid 40s over west central Kansas where dewpoints will be lower and winds could go light for a few hours around sunrise. Low temperatures in south central Kansas may only drop into the mid 50s where dewpoints are higher. During the day Saturday, mid level flow over the central Plains gradually becomes southwesterly with time as an upper level shortwave trough digs into the western states. This will result in surface cyclogenesis over southeast Colorado during the afternoon. Areas of southwest Kansas along the Oklahoma border should see high temperatures rising into the upper 80s to near 90 degrees with southerly winds increasing during the day. This could result in critical fire weather conditions over far southwest Kansas in the afternoon. .LONG TERM...(Saturday night through Friday) ISSUED AT 349 PM CDT FRI MAY 9 2014 The first issue during this period will be Saturday night. Rich gulf moisture is not too far southeast, meaning it`s as close as extreme southeast Oklahoma and north Texas. With the vigorous jet and upper level anomaly digging into the Rockies, the surface response will be rapidly falling pressure in the lee of the Rockies. The surface low should deepen in southeast Colorado. Boundary layer winds will become east to southeast and the aforementioned rich moisture will begin stream northwest towards my forecast area. Warm frontogenesis will take place and this will advance rapidly north by Saturday night. I see a small opportunity of elevated and nocturnal convection developing along the nose of the moisture surge across my far southeast area after dark Saturday night. Confidence is not high though. Sunday will be the "warm" day in advance of a strong surge of cold air that will be sweeping into the plains as the digging system into the Rockies lifts out into the plains. There should be a rather tight gradient of temperatures across my area and will adjust the grids accordingly. With the rich gulf moisture, strong uvv and surface convergence along the front the chance for thunderstorms will be high late Sunday and Sunday evening. Behind the front there should be continued lift and with strong cold air advection there should be low stratus and at least drizzle, if not light rain. Monday should be a rather raw day with clouds, blustery winds and some precipitation. My forecast highs may be a little optimistic but the trend is to definitely cooler temperatures. Beyond Monday, the flow will be northwest flow aloft with perhaps another minor wave sliding southeast which might promote showers about mid week. Overall temperatures will be below normal seasonal normals. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) ISSUED AT 1200 AM CDT SAT MAY 10 2014 VFR conditions will prevail at all TAF sites through early Saturday evening. As for winds, light southeasterly winds will persist across central and southwest Kansas overnight as a lee side trough remains anchored along the Kansas and Colorado border. Winds will become more light and variable Saturday as the surface trough shifts slowly eastward across western Kansas. && .PRELIMINARY POINT TEMPS/POPS... DDC 55 81 43 57 / 0 20 50 40 GCK 52 77 41 55 / 0 10 50 50 EHA 53 78 41 55 / 0 10 30 30 LBL 55 82 43 59 / 0 10 30 20 HYS 55 77 44 56 / 0 10 60 50 P28 63 91 49 65 / 0 40 50 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJohnson SHORT TERM...Gerard LONG TERM...Hutton AVIATION...JJohnson
AREA FORECAST DISCUSSION
NWS PADUCAH KY
930 PM CDT Sun May 11 2014 .UPDATE... Issued at 930 PM CDT SUN MAY 11 2014 The likelihood of lightning strikes has dropped low enough this evening that there will be no mention of them in the HWO or the gridded products overnight. Despite ridging in the mid levels, the tepid lower trop is such that a stray light rain shower cannot be ruled out overnight, however. && .SHORT TERM...(Tonight through Tuesday night) Issued at 317 PM CDT SUN MAY 11 2014 Pockets of surface-based instability continue to expand over the WFO PAH CWA this afternoon, aided by decent insolation and weak to moderate directional shear (25-35 knots) aloft (as evidenced by the anvil rain plumes oriented from northwest to southeast). The old cold pool has eroded over southeast IL and southwest IN from the morning convection, so distinct theta-e gradients are in place. Given the GOES Water Vapor imagery, the moisture gradient aloft implies a gradient in lapse rates as well, helping to enhance updrafts. (This is evidenced by the newly organized storms with hail in Southeast IL). The 12km RUC also suggests that the expended CAPE along and north of the implied surface warm frontal reflection arcing from northwest to southeast through southeast Illinois into northwest Kentucky. Further expenditure of CAPE through 01z suggests that the pool of convective instability should drop markedly. In addition, model heights are expected to rise this evening with a subtle change in balance takes place between the eastern U.S. ridge and the center of the sharpening trough over Western Nebraska. Expect that rain chances will be essentially nil over the entire WFO PAH CWA by midnight, as the warm frontal boundary moves well north of the area and shear decreases with time. As mentioned in yesterday`s discussion, channeled vorticity along the eastern limb of the trough near the inflection point between the trough/ridge circulation (cyclonic/anticyclonic flow) will aid in creating some lift in advance of an approaching moisture plume from the Gulf of Mexico around daybreak on Monday. This transition zone for convection will move slowly east through Monday afternoon, as the main trough actually sharpens and becomes slightly negatively tilted west of Iowa and Missouri Monday night into Tuesday morning. By 09z (4 am CDT) Tuesday morning, the cold front associated with this trough is expected to move into western sections of the WFO PAH Forecast area (Southwest IL/Southeast MO). By late evening Monday and into early Tuesday, the coverage of showers and thunderstorms should pick up significantly. It is at this time, that my concern for heavy rain potential will increase, with the potential for at least minor flooding by daybreak on Tuesday over parts of Southeast Missouri northeast to the Mississippi River. QPF values in excess of two inches would not be out of the question during that time period. The 12km NAM-WRF is actually suggesting a new closed circulation will develop at the based of the mean trough over the upper Midwest, somewhere near the OK/TX panhandles by Tuesday night, moving into southern Missouri by Wednesday evening. This is similar to what the ECMWF advertised in the Friday/Saturday model runs. This will lead to enhanced precipitation, both pre/post frontal as the frontal boundary remains fixed along the Interstate 57/55 corridor in Southern IL/Southeast Missouri. Most of the upright (thunderstorm) instability may be mixed out by Tuesday afternoon and night, but warm top (satellite reference) convection processes will likely take over increasing the effectiveness of the rainfall from Tuesday into Wednesday. There is still some question with respect to severe potential during this time period, but heavy rainfall still remains the dominant threat Tuesday into Wednesday. .LONG TERM...(Wednesday through Sunday) Issued at 417 PM CDT SUN MAY 11 2014 Confidence is fairly high concerning the general synoptic pattern in the Wed-Sun time frame. It is looking more and more like a high amplitude mid level trof will be carved out from southeast Canada southward all the way into the Ms River Valley by the Wed/Thu period. On east side of the trof, broad swly flow aloft will be evident. As a sfc low lifts ne along the spine of the Appalachians Wed, it appears showers will once again overspread most of the forecast area. Highest rain amounts will probably be over wrn KY and sw IN. Once the sfc low pulls off to the northeast Wed night, and the h50 trof axis moves east of the region, rain chcs should decrease considerably for much of the remainder of the extended. However, very low height fields and extensive daytime cloudiness behind the system will likely lead to an extended period of below normal temperatures. Highs are only expected to reach the 60s most locations Thu/Fri/Sat. && .AVIATION... Issued at 636 PM CDT SUN MAY 11 2014 There are just a few isolated showers left across the region early this evening, and they should dissipate completely in the next hour or two. KEVV is the most likely terminal to be impacted, but suspect that those developed on outflow to the south of KEVV and that they will not survive long north of that boundary. Outflow has created a light east or east southeast wind at KEVV and KOWB, but a south wind near 10kts should develop there by late evening. Elsewhere the south winds will continue through the night. South southwest winds will gust 20-25kts across the area Monday. The area should be completely in the warm sector Monday, and that should lead to much less convection than today. In fact, there may not be any across the area. Will keep all of the TAFs dry. Cannot rule out a periodic lower VFR ceiling Monday, but figure that it will primarily be a scattered cu deck. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DB SHORT TERM...Smith LONG TERM...GM AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
636 PM CDT Sun May 11 2014 .UPDATE... Issued at 636 PM CDT SUN MAY 11 2014 The Lake Wind Advisory will expire at 7 PM. The AVIATION section has been updated for the 00Z TAF issuance. && .SHORT TERM...(Tonight through Tuesday night) Issued at 317 PM CDT SUN MAY 11 2014 Pockets of surface-based instability continue to expand over the WFO PAH CWA this afternoon, aided by decent insolation and weak to moderate directional shear (25-35 knots) aloft (as evidenced by the anvil rain plumes oriented from northwest to southeast). The old cold pool has eroded over southeast IL and southwest IN from the morning convection, so distinct theta-e gradients are in place. Given the GOES Water Vapor imagery, the moisture gradient aloft implies a gradient in lapse rates as well, helping to enhance updrafts. (This is evidenced by the newly organized storms with hail in Southeast IL). The 12km RUC also suggests that the expended CAPE along and north of the implied surface warm frontal reflection arcing from northwest to southeast through southeast Illinois into northwest Kentucky. Further expenditure of CAPE through 01z suggests that the pool of convective instability should drop markedly. In addition, model heights are expected to rise this evening with a subtle change in balance takes place between the eastern U.S. ridge and the center of the sharpening trough over Western Nebraska. Expect that rain chances will be essentially nil over the entire WFO PAH CWA by midnight, as the warm frontal boundary moves well north of the area and shear decreases with time. As mentioned in yesterday`s discussion, channeled vorticity along the eastern limb of the trough near the inflection point between the trough/ridge circulation (cyclonic/anticyclonic flow) will aid in creating some lift in advance of an approaching moisture plume from the Gulf of Mexico around daybreak on Monday. This transition zone for convection will move slowly east through Monday afternoon, as the main trough actually sharpens and becomes slightly negatively tilted west of Iowa and Missouri Monday night into Tuesday morning. By 09z (4 am CDT) Tuesday morning, the cold front associated with this trough is expected to move into western sections of the WFO PAH Forecast area (Southwest IL/Southeast MO). By late evening Monday and into early Tuesday, the coverage of showers and thunderstorms should pick up significantly. It is at this time, that my concern for heavy rain potential will increase, with the potential for at least minor flooding by daybreak on Tuesday over parts of Southeast Missouri northeast to the Mississippi River. QPF values in excess of two inches would not be out of the question during that time period. The 12km NAM-WRF is actually suggesting a new closed circulation will develop at the based of the mean trough over the upper Midwest, somewhere near the OK/TX panhandles by Tuesday night, moving into southern Missouri by Wednesday evening. This is similar to what the ECMWF advertised in the Friday/Saturday model runs. This will lead to enhanced precipitation, both pre/post frontal as the frontal boundary remains fixed along the Interstate 57/55 corridor in Southern IL/Southeast Missouri. Most of the upright (thunderstorm) instability may be mixed out by Tuesday afternoon and night, but warm top (satellite reference) convection processes will likely take over increasing the effectiveness of the rainfall from Tuesday into Wednesday. There is still some question with respect to severe potential during this time period, but heavy rainfall still remains the dominant threat Tuesday into Wednesday. .LONG TERM...(Wednesday through Sunday) Issued at 417 PM CDT SUN MAY 11 2014 Confidence is fairly high concerning the general synoptic pattern in the Wed-Sun time frame. It is looking more and more like a high amplitude mid level trof will be carved out from southeast Canada southward all the way into the Ms River Valley by the Wed/Thu period. On east side of the trof, broad swly flow aloft will be evident. As a sfc low lifts ne along the spine of the Appalachians Wed, it appears showers will once again overspread most of the forecast area. Highest rain amounts will probably be over wrn KY and sw IN. Once the sfc low pulls off to the northeast Wed night, and the h50 trof axis moves east of the region, rain chcs should decrease considerably for much of the remainder of the extended. However, very low height fields and extensive daytime cloudiness behind the system will likely lead to an extended period of below normal temperatures. Highs are only expected to reach the 60s most locations Thu/Fri/Sat. && .AVIATION... Issued at 636 PM CDT SUN MAY 11 2014 There are just a few isolated showers left across the region early this evening, and they should dissipate completely in the next hour or two. KEVV is the most likely terminal to be impacted, but suspect that those developed on outflow to the south of KEVV and that they will not survive long north of that boundary. Outflow has created a light east or east southeast wind at KEVV and KOWB, but a south wind near 10kts should develop there by late evening. Elsewhere the south winds will continue through the night. South southwest winds will gust 20-25kts across the area Monday. The area should be completely in the warm sector Monday, and that should lead to much less convection than today. In fact, there may not be any across the area. Will keep all of the TAFs dry. Cannot rule out a periodic lower VFR ceiling Monday, but figure that it will primarily be a scattered cu deck. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS SHORT TERM...Smith LONG TERM...GM AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
143 PM EDT SAT MAY 10 2014 .UPDATE... ISSUED AT 1234 PM EDT SAT MAY 10 2014 THE FORECAST HAS BEEN PRETTY MUCH ON TRACK SO FAR TODAY. THE LATEST MODEL DATA HAS BEEN ABOUT AN HOUR OR SLOW WITH ITS TIMING OF A LINE OF CONVECTION ACROSS EASTERN KENTUCKY THROUGH EARLY THIS AFTERNOON. THE INHERITED FORECAST HAS BEEN MUCH CLOSER TO REALITY THAN THE MODELS IN THAT REGARD SO FAR...SO NO MAJOR CHANGES WERE MADE TO THE PRECIPITATION PROBABILITIES OR TIMING OF SHOWERS AND STORMS AS THEY MOVE ACROSS OUR AREA TODAY. SOME MINOR CHANGES WERE MADE TO THE HOURLY TEMPERATURES AND TODAYS MAX TEMPS BASED ON TRENDS SEEN IN OBSERVED DATA AND THE INFLUENCE OF PRECIPITATION AT SEVERAL OBSERVING STATIONS TO THE WEST OF THE WEATHER OFFICE. ALSO REMOVED ANY OUTDATED MORNING OR AFTERNOON WORDING FROM THE ZONE FORECAST PRODUCT. THE UPDATED ZONE FORECAST HAS ALREADY BEEN ISSUED. UPDATE ISSUED AT 803 AM EDT SAT MAY 10 2014 UPPER LEVEL SHORT WAVE CURRENTLY MOVING THROUGH THE MID MISSISSIPPI VALLEY REGION. COLD FRONTAL BOUNDARY JUST NORTH OF THE OHIO RIVER WILL ONLY MAKE LITTLE IF ANY PROGRESS SOUTHWARD. WHAT HAS BEEN A STATIONARY BAND OF SHOWERS AND THUNDERSTORMS OVER WEST CENTRAL KY IS SHOWING SIGNS OF FINALLY BEING KICKED EASTWARD BY APPROACHING UPPER LEVEL SHORT WAVE. THIS BAND WILL GRADUALLY SHIFT EASTWARD ACROSS EASTERN KENTUCKY THROUGH THE DAY. A COUPLE OF THE MOST RECENT RUNS OF THE HRRR SUGGEST THIS BAND WILL LIFT NORTHEASTWARD BY 15Z...MISSING MOST OF OUR FORECAST AREA IN THE PROCESS. AFTER A LULL IN ACTIVITY THE HRRR THEN REDEVELOPS SHOWER AND THUNDERSTORMS IN A SECOND WAVE WHICH ENTERS INTO OUR AREA FROM THE WEST BY 17-18Z. SHOWER ACTIVITY LINGERS A BIT LONGER INTO THE EARLY EVENING AS WELL WHEN COMPARED TO LOWER RESOLUTION MODELS. CURRENT SWATH OF PRECIPITATION EXTENDS SOUTHWESTWARD...WELL BACK TOWARDS TEXARKANA. NOT SURE WHAT THE HRRR IS PICKING UP ON BUT THOUGHTS ARE THAT CURRENT BAND OF SHOWERS WILL NOT LIFT OUT TO THE NORTHEAST PER THE HRRR. SEEMS MORE LIKELY THE BAND WILL CONTINUE TO GRADUALLY SHIFT EASTWARD...WITH ADDITIONAL REDEVELOPMENT OF CLUSTERS/LINE SEGMENTS FURTHER WEST BEHIND THE ORIGINAL BAND AS WE PROGRESS THROUGH THE DAY. EITHER WAY IT APPEARS LIKELY THAT JUST ABOUT EVERYONE WILL SEE SOME RAINFALL TODAY...AND HEAR A FEW CLAPS OF THUNDER FROM TIME TO TIME AS WELL. WITH SLOW MOVEMENT OF LINE EASTWARD ONLY OTHER CONCERN WOULD BE POTENTIAL OF TRAINING CELLS WHICH COULD PRODUCE SOME LOCALLY HEAVIER RAINFALL...AND MINOR FLOODING IN SPOTS. BASED ON KY MESONET RAINFALL IN GENERAL HAS BEEN ON THE LIGHTER SIDE. BUT A COUPLE OF THE UPSTREAM GAGES ARE REPORTING TOTALS OVER AN INCH NOW...ONE IS REPORTING AN INCH AND A HALF. RADAR ESTIMATES ARE EVEN HIGHER IN A FEW LOCATIONS SUCH AS BUTLER COUNTY WITH ESTIMATES OF BETWEEN 4 AND 7 INCHES OF TOTAL RAINFALL SO FAR. UNFORTUNATELY THERE IS NO GROUND TRUTH THERE BUT LMK HAS CONFIRMED THE POTENTIAL BASED ON INCOMING COOP REPORTS. WILL PASS ON CONCERNS TO FOLLOWING SHIFT. THANKS TO LMK FOR CHAT... COLLABORATION ON CONCERNS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 300 AM EDT SAT MAY 10 2014 MODELS ARE IN GOOD AGREEMENT DURING THE SHORT TERM. HOWEVER THERE ARE DIFFERENCES IN THE DETAILS...PARTICULARLY WITH RESPECT TO TIMING A BAND OF PRECIPITATION TO OUR WEST THROUGH THE AREA THIS MORNING... TODAY. SWATH OF SHOWERS AND THUNDERSTORMS TO OUR WEST HAS BEEN CREEPING SLOWLY EASTWARD BUT SHOULD PICK UP SPEED LATER THIS MORNING AS AN UPPER LEVEL SHORTWAVE LIFTS THIS BAND EASTWARD WHILE MOVING ACROSS THE REGION. FORECAST SOUNDINGS ARE MORE STABLE THAN THE PREVIOUS 12 TO 24 HOURS AND THERE ARE PLENTY OF STRIKES ASSOCIATED WITH THE BAND...AND EVEN A FEW CLOUD TO CLOUD STRIKES WITH ACTIVITY ON THE EASTERN FRINGE. WHILE CAN NOT RULE OUT AN ISOLD STRONG/SEVERE STORM...OVERALL SEVERE THREAT APPEARS MINIMAL. ATMOSPHERE STABILIZES QUICKLY TONIGHT AS ACTIVITY DIES OUT. AM NOT REAL IMPRESSED WITH POTENTIAL OF SHOWERS AND THUNDERSTORMS SUNDAY AS UPPER LEVEL SHORT WAVE RIDGING HELPS BUILD A WEAK CAP ACROSS THE AREA. THE GFS IS STRONGER THAN THE NAM WITH THIS CAP...PROBABLY DUE TO THE NAMS TENDENCY TO OVERDO SFC MOISTURE AND CONSEQUENTLY INSTABILITY. BUT WILL LEAVE A SLIGHT POP IN THE FORECAST FOR GOOD MEASURE AS THE TRUTH WILL PROBABLY BE SOMEWHERE IN THE MIDDLE...AND TO MATCH UP BETTER WITH NEIGHBORS. OTHERWISE...NUDGED TEMPS TOWARDS LATEST BLEND OF MODEL GUIDANCE. OVERALL TEMPS APPEARED IN GREAT SHAPE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 300 AM EDT SAT MAY 10 2014 OVERALL...WHILE MODELS CONTINUE TO SHOW INCONSISTENCIES...THE TREND IS FOR A SLOWER PROGRESSION OF AN UPPER LEVEL TROUGH AS IT PUSHES INTO THE REGION MID TO LATE WEEK. THE GFS APPEARS TO BE TRENDING TOWARDS THE SLOWER ECWMF WITH EACH SUBSEQUENT RUN...SO CLEARLY...THE SLOWER TREND NEEDS TO BE ADDRESSED WITH HIGHER POPS INTO THE END OF THE WEEK. AS IT STANDS NOW...STRONG RIDGING WILL PERSIST OVER THE EASTERN US INTO TUESDAY...AND POSSIBLY WEDNESDAY...LEADING TO THE CONTINUATION OF MILD WEATHER WITH DAYTIME HIGHS INTO THE 80S WITH A OUTSIDE CHANCE OF AN ISOLATED SHOWER OR STORM EACH AFTERNOON. HOWEVER...WITH WINDS NEVER COMPLETELY GOING SOUTHWEST...WE MAY KEEP SOME DOWNSLOPE COMPONENT OF THE WIND...WHICH MAY LIMIT ANY SHOWER OR STORM POTENTIAL THROUGH AT LEAST TUESDAY NIGHT. BY WEDNESDAY...AND ESPECIALLY INTO THURSDAY...A SHARP MID/UPPER LEVEL TROUGH WILL PROGRESS INTO THE OHIO RIVER VALLEY...WITH A STRONG SURFACE COLD FRONT PUSHING ACROSS THE AREA. STILL PLENTY OF UNCERTAINTY WITH EXACT TIMING OF THE FRONT...BUT IT DOES APPEAR AFTER A LONG STRETCH OF MILD WEATHER...WE WILL TURN MUCH COOLER AND UNSETTLED BY WEEKS END AND INTO NEXT WEEKEND. HIGHS MAY STRUGGLE TO GET OUT OF THE 50S OR 60S...DEPENDING ON THE DEGREE OF CLOUD COVER AND PRECIPITATION WITH THE UPPER LEVEL FEATURE. THE UPPER LEVEL LOW WILL EVENTUALLY CUT OFF SOMEWHERE OVER THE OHIO VALLEY OR GREAT LAKES REGION...AND EXACT PLACEMENT WILL DETERMINE HOW UNSETTLED THE WEATHER WILL REMAIN INTO THE WEEKEND. THUS...FOR NOW...WILL TRAIL OFF POPS AS WE HEAD INTO THE WEEKEND...BUT IF THE UPPER LEVEL LOW BECOMES MORE ANCHORED OVER EASTERN KENTUCKY...WE COULD BE LOOKING AT UNSETTLED WEATHER THROUGH THE WEEKEND. STILL PLENTY OF TIME TO IRON OUT THESE DETAILS. ITS SEEMS THE COOLER WEATHER WILL PERSIST THROUGH NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 143 PM EDT SAT MAY 10 2014 A LINE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PUSH ACROSS EASTERN KENTUCKY THIS AFTERNOON. THIS INITIAL LINE HAS CLEARED THE AIRPORTS AT JKL...LOZ...AND SME. SJS WILL EXPERIENCE SHOWER AND STORM ACTIVITY THROUGH 19 OR 20Z BEFORE THINGS BEGIN TO TAPER. AFTER A BRIEF LULL IN ACTIVITY...ANOTHER AREA OF SHOWERS AND STORMS IS EXPECTED TO MOVE ACROSS THE AREA LATER THIS AFTERNOON...PERHAPS IN THE 20 TO 23Z RANGE. THIS SECOND AREA OF PRECIPITATION WILL BEAR WATCHING TO GET A BETTER HANDLE ON HOW WIDESPREAD IT BECOMES AND IT EXACT DIRECTION AND SPEED OF MOVEMENT. IN GENERAL THE TAF SITES WILL EXPERIENCE VFR TO MVFR CONDITIONS FROM ANY EXISTING SHOWERS AND STORMS AND ANY FOG ASSOCIATED WITH THEM. WORSE CONDITIONS WILL BE POSSIBLE DURING HEAVY DOWNPOURS AND WINDY CONDITIONS IN ANY THUNDERSTORMS OR INTENSE RAIN SHOWERS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...RAY LONG TERM...KAS AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
1234 PM EDT SAT MAY 10 2014 .UPDATE... ISSUED AT 1234 PM EDT SAT MAY 10 2014 THE FORECAST HAS BEEN PRETTY MUCH ON TRACK SO FAR TODAY. THE LATEST MODEL DATA HAS BEEN ABOUT AN HOUR OR SLOW WITH ITS TIMING OF A LINE OF CONVECTION ACROSS EASTERN KENTUCKY THROUGH EARLY THIS AFTERNOON. THE INHERITED FORECAST HAS BEEN MUCH CLOSER TO REALITY THAN THE MODELS IN THAT REGARD SO FAR...SO NO MAJOR CHANGES WERE MADE TO THE PRECIPITATION PROBABILITIES OR TIMING OF SHOWERS AND STORMS AS THEY MOVE ACROSS OUR AREA TODAY. SOME MINOR CHANGES WERE MADE TO THE HOURLY TEMPERATURES AND TODAYS MAX TEMPS BASED ON TRENDS SEEN IN OBSERVED DATA AND THE INFLUENCE OF PRECIPITATION AT SEVERAL OBSERVING STATIONS TO THE WEST OF THE WEATHER OFFICE. ALSO REMOVED ANY OUTDATED MORNING OR AFTERNOON WORDING FROM THE ZONE FORECAST PRODUCT. THE UPDATED ZONE FORECAST HAS ALREADY BEEN ISSUED. UPDATE ISSUED AT 803 AM EDT SAT MAY 10 2014 UPPER LEVEL SHORT WAVE CURRENTLY MOVING THROUGH THE MID MISSISSIPPI VALLEY REGION. COLD FRONTAL BOUNDARY JUST NORTH OF THE OHIO RIVER WILL ONLY MAKE LITTLE IF ANY PROGRESS SOUTHWARD. WHAT HAS BEEN A STATIONARY BAND OF SHOWERS AND THUNDERSTORMS OVER WEST CENTRAL KY IS SHOWING SIGNS OF FINALLY BEING KICKED EASTWARD BY APPROACHING UPPER LEVEL SHORT WAVE. THIS BAND WILL GRADUALLY SHIFT EASTWARD ACROSS EASTERN KENTUCKY THROUGH THE DAY. A COUPLE OF THE MOST RECENT RUNS OF THE HRRR SUGGEST THIS BAND WILL LIFT NORTHEASTWARD BY 15Z...MISSING MOST OF OUR FORECAST AREA IN THE PROCESS. AFTER A LULL IN ACTIVITY THE HRRR THEN REDEVELOPS SHOWER AND THUNDERSTORMS IN A SECOND WAVE WHICH ENTERS INTO OUR AREA FROM THE WEST BY 17-18Z. SHOWER ACTIVITY LINGERS A BIT LONGER INTO THE EARLY EVENING AS WELL WHEN COMPARED TO LOWER RESOLUTION MODELS. CURRENT SWATH OF PRECIPITATION EXTENDS SOUTHWESTWARD...WELL BACK TOWARDS TEXARKANA. NOT SURE WHAT THE HRRR IS PICKING UP ON BUT THOUGHTS ARE THAT CURRENT BAND OF SHOWERS WILL NOT LIFT OUT TO THE NORTHEAST PER THE HRRR. SEEMS MORE LIKELY THE BAND WILL CONTINUE TO GRADUALLY SHIFT EASTWARD...WITH ADDITIONAL REDEVELOPMENT OF CLUSTERS/LINE SEGMENTS FURTHER WEST BEHIND THE ORIGINAL BAND AS WE PROGRESS THROUGH THE DAY. EITHER WAY IT APPEARS LIKELY THAT JUST ABOUT EVERYONE WILL SEE SOME RAINFALL TODAY...AND HEAR A FEW CLAPS OF THUNDER FROM TIME TO TIME AS WELL. WITH SLOW MOVEMENT OF LINE EASTWARD ONLY OTHER CONCERN WOULD BE POTENTIAL OF TRAINING CELLS WHICH COULD PRODUCE SOME LOCALLY HEAVIER RAINFALL...AND MINOR FLOODING IN SPOTS. BASED ON KY MESONET RAINFALL IN GENERAL HAS BEEN ON THE LIGHTER SIDE. BUT A COUPLE OF THE UPSTREAM GAGES ARE REPORTING TOTALS OVER AN INCH NOW...ONE IS REPORTING AN INCH AND A HALF. RADAR ESTIMATES ARE EVEN HIGHER IN A FEW LOCATIONS SUCH AS BUTLER COUNTY WITH ESTIMATES OF BETWEEN 4 AND 7 INCHES OF TOTAL RAINFALL SO FAR. UNFORTUNATELY THERE IS NO GROUND TRUTH THERE BUT LMK HAS CONFIRMED THE POTENTIAL BASED ON INCOMING COOP REPORTS. WILL PASS ON CONCERNS TO FOLLOWING SHIFT. THANKS TO LMK FOR CHAT... COLLABORATION ON CONCERNS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 300 AM EDT SAT MAY 10 2014 MODELS ARE IN GOOD AGREEMENT DURING THE SHORT TERM. HOWEVER THERE ARE DIFFERENCES IN THE DETAILS...PARTICULARLY WITH RESPECT TO TIMING A BAND OF PRECIPITATION TO OUR WEST THROUGH THE AREA THIS MORNING... TODAY. SWATH OF SHOWERS AND THUNDERSTORMS TO OUR WEST HAS BEEN CREEPING SLOWLY EASTWARD BUT SHOULD PICK UP SPEED LATER THIS MORNING AS AN UPPER LEVEL SHORTWAVE LIFTS THIS BAND EASTWARD WHILE MOVING ACROSS THE REGION. FORECAST SOUNDINGS ARE MORE STABLE THAN THE PREVIOUS 12 TO 24 HOURS AND THERE ARE PLENTY OF STRIKES ASSOCIATED WITH THE BAND...AND EVEN A FEW CLOUD TO CLOUD STRIKES WITH ACTIVITY ON THE EASTERN FRINGE. WHILE CAN NOT RULE OUT AN ISOLD STRONG/SEVERE STORM...OVERALL SEVERE THREAT APPEARS MINIMAL. ATMOSPHERE STABILIZES QUICKLY TONIGHT AS ACTIVITY DIES OUT. AM NOT REAL IMPRESSED WITH POTENTIAL OF SHOWERS AND THUNDERSTORMS SUNDAY AS UPPER LEVEL SHORT WAVE RIDGING HELPS BUILD A WEAK CAP ACROSS THE AREA. THE GFS IS STRONGER THAN THE NAM WITH THIS CAP...PROBABLY DUE TO THE NAMS TENDENCY TO OVERDO SFC MOISTURE AND CONSEQUENTLY INSTABILITY. BUT WILL LEAVE A SLIGHT POP IN THE FORECAST FOR GOOD MEASURE AS THE TRUTH WILL PROBABLY BE SOMEWHERE IN THE MIDDLE...AND TO MATCH UP BETTER WITH NEIGHBORS. OTHERWISE...NUDGED TEMPS TOWARDS LATEST BLEND OF MODEL GUIDANCE. OVERALL TEMPS APPEARED IN GREAT SHAPE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 300 AM EDT SAT MAY 10 2014 OVERALL...WHILE MODELS CONTINUE TO SHOW INCONSISTENCIES...THE TREND IS FOR A SLOWER PROGRESSION OF AN UPPER LEVEL TROUGH AS IT PUSHES INTO THE REGION MID TO LATE WEEK. THE GFS APPEARS TO BE TRENDING TOWARDS THE SLOWER ECWMF WITH EACH SUBSEQUENT RUN...SO CLEARLY...THE SLOWER TREND NEEDS TO BE ADDRESSED WITH HIGHER POPS INTO THE END OF THE WEEK. AS IT STANDS NOW...STRONG RIDGING WILL PERSIST OVER THE EASTERN US INTO TUESDAY...AND POSSIBLY WEDNESDAY...LEADING TO THE CONTINUATION OF MILD WEATHER WITH DAYTIME HIGHS INTO THE 80S WITH A OUTSIDE CHANCE OF AN ISOLATED SHOWER OR STORM EACH AFTERNOON. HOWEVER...WITH WINDS NEVER COMPLETELY GOING SOUTHWEST...WE MAY KEEP SOME DOWNSLOPE COMPONENT OF THE WIND...WHICH MAY LIMIT ANY SHOWER OR STORM POTENTIAL THROUGH AT LEAST TUESDAY NIGHT. BY WEDNESDAY...AND ESPECIALLY INTO THURSDAY...A SHARP MID/UPPER LEVEL TROUGH WILL PROGRESS INTO THE OHIO RIVER VALLEY...WITH A STRONG SURFACE COLD FRONT PUSHING ACROSS THE AREA. STILL PLENTY OF UNCERTAINTY WITH EXACT TIMING OF THE FRONT...BUT IT DOES APPEAR AFTER A LONG STRETCH OF MILD WEATHER...WE WILL TURN MUCH COOLER AND UNSETTLED BY WEEKS END AND INTO NEXT WEEKEND. HIGHS MAY STRUGGLE TO GET OUT OF THE 50S OR 60S...DEPENDING ON THE DEGREE OF CLOUD COVER AND PRECIPITATION WITH THE UPPER LEVEL FEATURE. THE UPPER LEVEL LOW WILL EVENTUALLY CUT OFF SOMEWHERE OVER THE OHIO VALLEY OR GREAT LAKES REGION...AND EXACT PLACEMENT WILL DETERMINE HOW UNSETTLED THE WEATHER WILL REMAIN INTO THE WEEKEND. THUS...FOR NOW...WILL TRAIL OFF POPS AS WE HEAD INTO THE WEEKEND...BUT IF THE UPPER LEVEL LOW BECOMES MORE ANCHORED OVER EASTERN KENTUCKY...WE COULD BE LOOKING AT UNSETTLED WEATHER THROUGH THE WEEKEND. STILL PLENTY OF TIME TO IRON OUT THESE DETAILS. ITS SEEMS THE COOLER WEATHER WILL PERSIST THROUGH NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 803 AM EDT SAT MAY 10 2014 MODELS AND GUIDANCE ARE HOLDING OFF ON THE BULK OF SHOWER AND THUNDERSTORM ACTIVITY UNTIL LATER THIS MORNING AND MID DAY AS AN UPPER LEVEL DISTURBANCE PASSES THROUGH THE REGION TODAY. TRIED TO TIME ONSET OF SHOWERS INTO THE AREA BASED ON MOST RECENT HIGH RESOLUTION MODELS AND EXTRAPOLATION OF CURRENT BAND INTO THE AREA. FEEL THERE WILL BE A 4 TO 6 HOUR WINDOW OF SHOWER AND THUNDERSTORM ACTIVITY AT EACH TERMINAL CENTERED SOMEWHERE AROUND 17-20Z. IN GENERAL CIGS HAVE BEEN DROPPING TO ABOUT 3K FT AND VSBYS TO AROUND 1-2SM WITH PASSING THUNDERSTORM CELLS. CONDITIONS WOULD BE ONLY TEMPORARY WITH PASSING STORMS. WILL AMEND TAFS FOR TEMPO GROUPS ONCE WE ARE ABLE TO GET BETTER TIMING OF ANY STORMS ON STATION. SURFACE FRONTAL BOUNDARY WILL WASH OUT JUST TO OUR NORTH. WITH RAIN EXPECTED TODAY AND NO CLEAR PUSH OF DRIER AIR INTO OUR FORECAST AREA HELD ONTO SOME LIGHT MVFR MIST/FOG IN THE FORECAST AFTER 0Z. WINDS WILL BE SOUTHERLY AND LIGHT...WITH A TENDENCY TO INCREASE TO AROUND 10 KTS AND BECOME A BIT MORE WESTERLY LATER THIS AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...RAY LONG TERM...KAS AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
803 AM EDT SAT MAY 10 2014 .UPDATE... ISSUED AT 803 AM EDT SAT MAY 10 2014 UPPER LEVEL SHORT WAVE CURRENTLY MOVING THROUGH THE MID MISSISSIPPI VALLEY REGION. COLD FRONTAL BOUNDARY JUST NORTH OF THE OHIO RIVER WILL ONLY MAKE LITTLE IF ANY PROGRESS SOUTHWARD. WHAT HAS BEEN A STATIONARY BAND OF SHOWERS AND THUNDERSTORMS OVER WEST CENTRAL KY IS SHOWING SIGNS OF FINALLY BEING KICKED EASTWARD BY APPROACHING UPPER LEVEL SHORT WAVE. THIS BAND WILL GRADUALLY SHIFT EASTWARD ACROSS EASTERN KENTUCKY THROUGH THE DAY. A COUPLE OF THE MOST RECENT RUNS OF THE HRRR SUGGEST THIS BAND WILL LIFT NORTHEASTWARD BY 15Z...MISSING MOST OF OUR FORECAST AREA IN THE PROCESS. AFTER A LULL IN ACTIVITY THE HRRR THEN REDEVELOPS SHOWER AND THUNDERSTORMS IN A SECOND WAVE WHICH ENTERS INTO OUR AREA FROM THE WEST BY 17-18Z. SHOWER ACTIVITY LINGERS A BIT LONGER INTO THE EARLY EVENING AS WELL WHEN COMPARED TO LOWER RESOLUTION MODELS. CURRENT SWATH OF PRECIPITATION EXTENDS SOUTHWESTWARD...WELL BACK TOWARDS TEXARKANA. NOT SURE WHAT THE HRRR IS PICKING UP ON BUT THOUGHTS ARE THAT CURRENT BAND OF SHOWERS WILL NOT LIFT OUT TO THE NORTHEAST PER THE HRRR. SEEMS MORE LIKELY THE BAND WILL CONTINUE TO GRADUALLY SHIFT EASTWARD...WITH ADDITIONAL REDEVELOPMENT OF CLUSTERS/LINE SEGMENTS FURTHER WEST BEHIND THE ORIGINAL BAND AS WE PROGRESS THROUGH THE DAY. EITHER WAY IT APPEARS LIKELY THAT JUST ABOUT EVERYONE WILL SEE SOME RAINFALL TODAY...AND HEAR A FEW CLAPS OF THUNDER FROM TIME TO TIME AS WELL. WITH SLOW MOVEMENT OF LINE EASTWARD ONLY OTHER CONCERN WOULD BE POTENTIAL OF TRAINING CELLS WHICH COULD PRODUCE SOME LOCALLY HEAVIER RAINFALL...AND MINOR FLOODING IN SPOTS. BASED ON KY MESONET RAINFALL IN GENERAL HAS BEEN ON THE LIGHTER SIDE. BUT A COUPLE OF THE UPSTREAM GAGES ARE REPORTING TOTALS OVER AN INCH NOW...ONE IS REPORTING AN INCH AND A HALF. RADAR ESTIMATES ARE EVEN HIGHER IN A FEW LOCATIONS SUCH AS BUTLER COUNTY WITH ESTIMATES OF BETWEEN 4 AND 7 INCHES OF TOTAL RAINFALL SO FAR. UNFORTUNATELY THERE IS NO GROUND TRUTH THERE BUT LMK HAS CONFIRMED THE POTENTIAL BASED ON INCOMING COOP REPORTS. WILL PASS ON CONCERNS TO FOLLOWING SHIFT. THANKS TO LMK FOR CHAT... COLLABORATION ON CONCERNS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 300 AM EDT SAT MAY 10 2014 MODELS ARE IN GOOD AGREEMENT DURING THE SHORT TERM. HOWEVER THERE ARE DIFFERENCES IN THE DETAILS...PARTICULARLY WITH RESPECT TO TIMING A BAND OF PRECIPITATION TO OUR WEST THROUGH THE AREA THIS MORNING... TODAY. SWATH OF SHOWERS AND THUNDERSTORMS TO OUR WEST HAS BEEN CREEPING SLOWLY EASTWARD BUT SHOULD PICK UP SPEED LATER THIS MORNING AS AN UPPER LEVEL SHORTWAVE LIFTS THIS BAND EASTWARD WHILE MOVING ACROSS THE REGION. FORECAST SOUNDINGS ARE MORE STABLE THAN THE PREVIOUS 12 TO 24 HOURS AND THERE ARE PLENTY OF STRIKES ASSOCIATED WITH THE BAND...AND EVEN A FEW CLOUD TO CLOUD STRIKES WITH ACTIVITY ON THE EASTERN FRINGE. WHILE CAN NOT RULE OUT AN ISOLD STRONG/SEVERE STORM...OVERALL SEVERE THREAT APPEARS MINIMAL. ATMOSPHERE STABILIZES QUICKLY TONIGHT AS ACTIVITY DIES OUT. AM NOT REAL IMPRESSED WITH POTENTIAL OF SHOWERS AND THUNDERSTORMS SUNDAY AS UPPER LEVEL SHORT WAVE RIDGING HELPS BUILD A WEAK CAP ACROSS THE AREA. THE GFS IS STRONGER THAN THE NAM WITH THIS CAP...PROBABLY DUE TO THE NAMS TENDENCY TO OVERDO SFC MOISTURE AND CONSEQUENTLY INSTABILITY. BUT WILL LEAVE A SLIGHT POP IN THE FORECAST FOR GOOD MEASURE AS THE TRUTH WILL PROBABLY BE SOMEWHERE IN THE MIDDLE...AND TO MATCH UP BETTER WITH NEIGHBORS. OTHERWISE...NUDGED TEMPS TOWARDS LATEST BLEND OF MODEL GUIDANCE. OVERALL TEMPS APPEARED IN GREAT SHAPE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 300 AM EDT SAT MAY 10 2014 OVERALL...WHILE MODELS CONTINUE TO SHOW INCONSISTENCIES...THE TREND IS FOR A SLOWER PROGRESSION OF AN UPPER LEVEL TROUGH AS IT PUSHES INTO THE REGION MID TO LATE WEEK. THE GFS APPEARS TO BE TRENDING TOWARDS THE SLOWER ECWMF WITH EACH SUBSEQUENT RUN...SO CLEARLY...THE SLOWER TREND NEEDS TO BE ADDRESSED WITH HIGHER POPS INTO THE END OF THE WEEK. AS IT STANDS NOW...STRONG RIDGING WILL PERSIST OVER THE EASTERN US INTO TUESDAY...AND POSSIBLY WEDNESDAY...LEADING TO THE CONTINUATION OF MILD WEATHER WITH DAYTIME HIGHS INTO THE 80S WITH A OUTSIDE CHANCE OF AN ISOLATED SHOWER OR STORM EACH AFTERNOON. HOWEVER...WITH WINDS NEVER COMPLETELY GOING SOUTHWEST...WE MAY KEEP SOME DOWNSLOPE COMPONENT OF THE WIND...WHICH MAY LIMIT ANY SHOWER OR STORM POTENTIAL THROUGH AT LEAST TUESDAY NIGHT. BY WEDNESDAY...AND ESPECIALLY INTO THURSDAY...A SHARP MID/UPPER LEVEL TROUGH WILL PROGRESS INTO THE OHIO RIVER VALLEY...WITH A STRONG SURFACE COLD FRONT PUSHING ACROSS THE AREA. STILL PLENTY OF UNCERTAINTY WITH EXACT TIMING OF THE FRONT...BUT IT DOES APPEAR AFTER A LONG STRETCH OF MILD WEATHER...WE WILL TURN MUCH COOLER AND UNSETTLED BY WEEKS END AND INTO NEXT WEEKEND. HIGHS MAY STRUGGLE TO GET OUT OF THE 50S OR 60S...DEPENDING ON THE DEGREE OF CLOUD COVER AND PRECIPITATION WITH THE UPPER LEVEL FEATURE. THE UPPER LEVEL LOW WILL EVENTUALLY CUT OFF SOMEWHERE OVER THE OHIO VALLEY OR GREAT LAKES REGION...AND EXACT PLACEMENT WILL DETERMINE HOW UNSETTLED THE WEATHER WILL REMAIN INTO THE WEEKEND. THUS...FOR NOW...WILL TRAIL OFF POPS AS WE HEAD INTO THE WEEKEND...BUT IF THE UPPER LEVEL LOW BECOMES MORE ANCHORED OVER EASTERN KENTUCKY...WE COULD BE LOOKING AT UNSETTLED WEATHER THROUGH THE WEEKEND. STILL PLENTY OF TIME TO IRON OUT THESE DETAILS. ITS SEEMS THE COOLER WEATHER WILL PERSIST THROUGH NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 803 AM EDT SAT MAY 10 2014 MODELS AND GUIDANCE ARE HOLDING OFF ON THE BULK OF SHOWER AND THUNDERSTORM ACTIVITY UNTIL LATER THIS MORNING AND MID DAY AS AN UPPER LEVEL DISTURBANCE PASSES THROUGH THE REGION TODAY. TRIED TO TIME ONSET OF SHOWERS INTO THE AREA BASED ON MOST RECENT HIGH RESOLUTION MODELS AND EXTRAPOLATION OF CURRENT BAND INTO THE AREA. FEEL THERE WILL BE A 4 TO 6 HOUR WINDOW OF SHOWER AND THUNDERSTORM ACTIVITY AT EACH TERMINAL CENTERED SOMEWHERE AROUND 17-20Z. IN GENERAL CIGS HAVE BEEN DROPPING TO ABOUT 3K FT AND VSBYS TO AROUND 1-2SM WITH PASSING THUNDERSTORM CELLS. CONDITIONS WOULD BE ONLY TEMPORARY WITH PASSING STORMS. WILL AMEND TAFS FOR TEMPO GROUPS ONCE WE ARE ABLE TO GET BETTER TIMING OF ANY STORMS ON STATION. SURFACE FRONTAL BOUNDARY WILL WASH OUT JUST TO OUR NORTH. WITH RAIN EXPECTED TODAY AND NO CLEAR PUSH OF DRIER AIR INTO OUR FORECAST AREA HELD ONTO SOME LIGHT MVFR MIST/FOG IN THE FORECAST AFTER 0Z. WINDS WILL BE SOUTHERLY AND LIGHT...WITH A TENDENCY TO INCREASE TO AROUND 10 KTS AND BECOME A BIT MORE WESTERLY LATER THIS AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...RAY LONG TERM...KAS AVIATION...RAY
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
109 AM EDT Sat May 10 2014 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1130 PM EDT Fri May 9 2014 Did an update to increase POPs west of I-65 overnight. Models aren`t handling this evening`s convection very well. Storms continue to re-generate from SE Missouri through south Indiana/central KY. This is courtesy of multiple waves riding northeast along the south side of an upper trough to our north. The associate sfc boundary still sits well to our west over central MO/IL. Therefore, feel scattered shower/storms will continue overnight. A few high-res models and the 18Z/0Z NAM runs indicate a more solid area of showers/storms may form in our area (mainly over KY) late tonight into tomorrow morning. Will continue 60-70% POPs during that time frame. Think that storms will be mostly sub-severe overnight in an elevated environment. Pea size hail and perhaps a wind gust up to 40 mph may be possible in the strongest storms. Only made minor tweaks to temps/dewpts. Low temps will be in the lower 60s overnight. Issued at 810 PM EDT Fri May 9 2014 Did a quick update to better time POPs as the line of showers and storms moves through the region. The line has become pretty solid as far as coverage goes, but overall strength of storms has declined. The strongest storms will likely contain 35 to 45 mph wind gusts and perhaps some small hail. However, the convection is moving into a more unfavorable environment so do expect storms to continue to decrease in strength as the evening wears on. This round of storms should pass through the area by midnight. We`ll see a break in convection with another round looking likely late tonight into tomorrow morning. .SHORT TERM (Now through Saturday Night)... Issued at 305 PM EDT Fri May 9 2014 In the near term, rainfall from this morning continues to move NE but is still hanging in there over east-central KY. The rain will exit our forecast area in the next 1-2 hrs. Otherwise, conditions are dry with ample cloud cover over the rest of the region, with some cumulus clouds now starting to emerge with modest diurnal warming and decent low-level moisture. Nevertheless, the atmosphere remains relatively stable at this time, as evidenced by current SPC mesoanalysis. Thus, expect mainly rain free weather for the next few hours over central KY and south-central IN as temperatures top out thru the 70s to around 80 west. Meanwhile, convection continues to slowly develop along and ahead of a low-level frontal boundary and confluent zone from southwest IL into south-central MO. Latest SPC mesoanalysis shows an axis of -4 to -6 surface-based LI values and around 1000 J/kg CAPE in this axis. All short-range models and the latest HRRR and SPC SREF suggest this convection will continue to develop and expand E-NE late this afternoon and evening. Model soundings in our area show lapse rates increasing late this afternoon and evening, especially aloft resulting in a more conducive environment in time to develop and maintain convection within. As a result, will ramp up POPs this evening, first over south-central IN and northwest KY, then eastward later tonight. The best chances for severe storms are to our west in the area of the current SPC severe thunderstorm watch, enhanced by good instability and deep-layer speed shear (with a strong upper jet advancing eastward). As the storms move east later tonight, they may have a tendency to become slightly elevated with modest nocturnal cooling over our area. Nevertheless, the boundary layer may stay adequately mixed to allow some downward momentum transport from the strongest cells to produce isolated strong or damaging winds, mainly along and west of the I-65 corridor. After the storms move through, can`t totally rule out additional scattered showers and isolated thunderstorms well after midnight and into Saturday morning as a mid-level shortwave approaches. During the day Saturday, the shortwave will pass through our area. This could continue the chance for scattered showers and storms over eastern and southern forecast area in the morning, but should effectively clear things out later in the day. As a result, much of the afternoon should be precipitation free with temperatures rising through the 70s. If enough sunshine occurs in the afternoon, could see around 80 or lower 80s in western half of forecast area. Air mass will begin to destabilize again Saturday afternoon in the wake of the morning showers, but forcing should be quite limited in the wake of the morning shortwave. Therefore, expect only isolated cell redevelopment by late afternoon mainly over western and northern areas of forecast area. This activity could become a little more prevalent, especially northern half of forecast area, Saturday night if a model weak signal of another approaching shortwave proves correct. .LONG TERM (Sunday through Friday)... Issued at 250 PM EDT Fri May 9 2014 The long term period will be fairly active with multiple chances for showers and thunderstorms. In addition, a big shift in the upper air pattern will bring much cooler temperatures by the end of the next work week. For Sunday through Monday ridging will be building aloft. At the surface, high pressure will be centered off the east coast. Southerly winds on the back side of this high pressure will usher in warm and moist air to the lower Ohio Valley. Temperatures on Sunday will warm into the lower to mid 80s. Soundings show surface based instability developing during the afternoon and little to no cap across the area. However, with the lack of a trigger, storms look to remain scattered in nature and should mostly dissipate during the evening hours. For Monday soundings show more of a cap in place, so rain chances look to be less than Sunday. However, isolated to scattered showers and storms will still be possible. Highs will be in the mid 80s. A cold front will approach and move through the area during the Tuesday through Wednesday time frame. There is still quite a bit of discrepancy in the timing of this frontal passage. Thus, have gone with pops over a wider time frame than is expected with the frontal passage to account for uncertainty. For now, it looks like Tuesday/Tuesday night will be the best chance for showers and storms. However, if slower solutions pan out, chances will linger into Wednesday. The timing issue with the front will also have quite an impact on temperatures mid week as a trough will move in behind this system. This will usher in cooler air for the end of the week. Highs Thursday and Friday will be in the lower to mid 60s with lows in the upper 40s. There may be a slight chance of rain toward the end of the long term as a weak disturbance moves through the flow aloft, but timing with these is usually fairly questionable this far out. && .AVIATION (06Z TAF Update)... Issued at 107 AM EDT Sat May 10 2014 A rather complex TAF forecast is in store, as several boundaries from earlier convection are currently sparking convection. Over the next couple of hours, convection should remain scattered in nature. However, there is a subtle signal in guidance that convection will increase before dawn as another shortwave trough ejects north into the region. The best coverage of this precip looks to be across KBWG and KLEX. KSDF looks to remain on the northern edge of the better coverage of showers and embedded thunderstorms, but certainly they cannot be ruled out at any time overnight into Saturday morning. MVFR ceilings will likely move into all terminals overnight, especially as the steadier precipitation pushes in just before dawn. After more widespread coverage of showers/storms Saturday morning, they should become more isolated in nature by the afternoon hours. Winds will be out of the SSW at 10-15 knots. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........AMS Short Term.....TWF Long Term......EER Aviation.......KJD
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1028 PM CDT SUN MAY 11 2014 .DISCUSSION... INTERESTING FORECAST UPDATE FOR THE REMAINDER OF THE OVERNIGHT HOURS. CONVECTION ACROSS NATCHITOCHES PARISH HAS FINALLY DISSIPATED BUT RENEWED CONVECTION CONTINUES TO DEVELOP ACROSS DEEP EAST TEXAS AND SHOWS SIGNS OF EXPANDING NORTH AND WEST. THIS WOULD MAKE SENSE AS LATEST RUN OF THE HRRR SUGGESTS INCREASING CAPE OVERNIGHT ACROSS OUR WESTERN HALF. CONVECTION IS PROBABLY BEING AIDED BY A 50KT LOW LEVEL JET OFF SHV`S WSR-88D VAD WIND PROFILER. A QUICK LOOK AT ISENTROPIC SFCS NEAR OR SLIGHTLY ABOVE THE 930MB LEVEL SUGGEST A CONTINUATION OF ISENTROPIC LIFT WITH LOW CONDENSATION PRESSURE DEFICITS ACROSS OUR WESTERN HALF AS WELL. HAVING SAID ALL THIS...FOR THE UPDATE...WILL CONTINUE WITH A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE REMAINDER OF THE NIGHT ACROSS ALL ZONES...EVEN THOUGH I`M A LITTLE MORE CERTAIN OF THE BEST COVERAGE BEING ACROSS OUR WESTERN ZONES WHERE THE INSTABILITY OVERNIGHT WILL BE GREATER. TEMPERATURES AS OF 03Z ARE RUNNING A LITTLE WARMER THAN THIS TIME AND GIVEN THE QUICK RETURN TO THE LOW LEVEL CLOUD COVER ALREADY SEEN ON IR IMAGERY ALONG AND SOUTH OF A LFK...SHV...MLU LINE...ANOTHER WARM NIGHT IS IN STORE ACROSS THE REGION. HOURLY TEMPS ARE ALMOST DEAD ON WITH FCST HOURLY TEMPS AND OVERNIGHT MINS ARE FORECAST TO BE SOME 2 TO 3 DEGREES WARMER THAN LAST NIGHT. FOR THAT REASON...TEMPS APPEAR TO BE IN PRETTY GOOD SHAPE. EXPECTING SOUTHEAST WINDS NEAR 10 TO 15 MPH AREAWIDE WITH AN OCCASIONAL GUST FROM TIME TO TIME GIVEN THE STRONG PRESSURE GRADIENT IN THE LOWER LEVELS. ONLY UPDATE NECESSARY APPEAR TO BE AN EXTENSION TO THE POP FORECAST SPATIALLY BUT OTHERWISE...NO OTHER CHANGES ARE NECESSARY. FCST UPDATE OUT SHORTLY...13. && .PREV DISCUSSION... /ISSUED 658 PM CDT SUN MAY 11 2014/ AVIATION... FOR THE 12/00Z TAF ISSUE...EXPECT VFR FLIGHT WEATHER TO BEGIN THE 24 HOUR FORECAST PERIOD MOST LOCATIONS. HOWEVER...THROUGH 02Z... ISOLATED TSTMS WILL BE ONGOING IN NORTH CENTRAL LOUISIANA INTO SOUTH CENTRAL ARKANSAS. THIS CONVECTION WILL BRING MODERATE TO SEVERE TURBULENCE AND SURFACE WIND GUSTS BETWEEN 30 AND 40 KTS. AFTER 06Z...MVFR TO IFR CONDITIONS WILL BEGIN TO RETURN...AS SOUTHERLY WIND CONTINUES TO BRING MOISTURE INTO THE REGION. EXPECT THE FIRST CIGS AROUND 2 KFT...HOWEVER BY 09Z AND CONTINUING UNTIL 14Z...IFR CIGS BETWEEN 5 HUNDRED AND 1 KFT WILL BE COMMON ACROSS THE REGION. LIGHT FOG WILL ACCOMPANY THE LOWER CIGS AT A FEW TERMINALS WITH VSBYS BETWEEN 3 AND 5 MILES. VFR SHOULD RETURN TO MOST LOCATIONS BY 15Z...WITH CIGS 3 TO 4 KFT. ISOLATED TSTMS WILL DEVELOP WITH AFTERNOON HEATING...BECOMING MORE NUMEROUS WESTERN AREAS AFTER 21Z. SURFACE WIND SOUTH 5 TO 10 KTS TONIGHT...INCREASING UP TO 15 KTS WITH GUSTS 20 TO 25 KTS AFTER 14Z. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 73 86 67 79 57 / 20 50 60 70 50 MLU 70 86 67 83 60 / 20 50 50 60 50 DEQ 71 82 60 70 51 / 20 60 80 70 50 TXK 71 83 62 72 54 / 20 60 80 70 50 ELD 70 84 66 78 55 / 20 50 60 70 50 TYR 73 84 61 70 52 / 20 60 80 60 50 GGG 73 85 65 74 54 / 20 50 80 70 50 LFK 73 87 69 79 55 / 20 50 60 70 50 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 13
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1238 PM CDT SAT MAY 10 2014 .AVIATION... VFR CONDITIONS EXPECTED TODAY AND THIS EVENING WITH HIGH BASED CEILINGS EVENTUALLY CLEARING FROM WEST TO EAST. MARINE LAYER CLOUDS LIKELY TO DEVELOP OVERNIGHT TO BRING A BRIEF PERIOD OF MVFR CIGS BASED AROUND 1500 FT THAT MIXES OUT AFTER 14Z. AIR MASS HAS BECOME LESS UNSTABLE AND CONVECTION SHOULD REMAIN LESS THAN 30 PERCENT COVERAGE/CONFIDENCE TO MENTION IN ANY TAF LOCATION. 24/RR && .PREV DISCUSSION... /ISSUED 1011 AM CDT SAT MAY 10 2014/ SOUNDING DISCUSSION... PW VALUES HAVE DROPPED FROM 2.17" AT 00Z(1900CST YESTERDAY) TO 1.68" AT 12Z THIS MORNING. THIS IS EVIDENT FROM THE DRY LAYER THAT HAS DEVELOPED BETWEEN THE SFC UP TO 850MB. YESTERDAYS SOUNDING SHOWED A VERY SHALLOW COOL POOL THAT WAS RESPONSIBLE FOR GIVING THE MUCH NEEDED INITIAL LIFT TO THE SFC PARCELS. ONCE PARCELS REACHED ~975MB OR ~1100 FEET...THE PARCEL BECAME MOIST ADIABATIC ALL THE WAY UP TO 300MB AND AT 14.5 G/KG MIXING RATIO(YES 14.5)...THESE VARIABLES POINT TO A VERY TROPICAL AIR MASS WHICH MAY HAVE CAME FROM THE DEEP MOISTURE LOADING FROM THE OLD TROPICAL SYSTEM OFF THE WEST COAST OF MEXICO. THIS MORNINGS SOUNDING DOES NOT SHOW THAT DEPTH OF MOISTURE ANY LONGER. PREV DISCUSSION... /ISSUED 856 AM CDT SAT MAY 10 2014/ UPDATE... SENDING UPDATED ZONES TO REMOVE HEADLINES AT TOP OF THE HOUR. FLASH FLOOD WATCH ALLOWED TO EXPRIRE AT 9 AM AS SCHEDULED. 24/RR PREV DISCUSSION... /ISSUED 342 AM CDT SAT MAY 10 2014/ SYNOPSIS... SURFACE LOW CENTERED OVER EASTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD AND SOUTHWESTWARD THROUGH THE OHIO VALLEY AND INTO SOUTH CENTRAL MISSOURI WHERE IT HAS BECOME STATIONARY. LARGE SHIELD OF LIGHT TO MODERATE RAINFALL OVER NORTHERN GULF COAST REGION IS GRADUALLY ERODING AS OUTFLOW BOUNDARY FROM EARLIER CONVECTION HELPS CUT OFF MOISTURE SOURCE. TEMPS SITTING IN THE MID TO UPPER 60S WITH DEWPOINTS IN THE LOW TO MID 60S. DISCUSSION... HAVE CHOSEN TO LEAVE THE FLASH FLOOD WATCH IN PLACE JUST IN CASE OF ANY UNEXPECTED REDEVELOPMENT OF HEAVIER STORMS DURING THE NEXT FEW HOURS. THE GROUND IS NOW SATURATED ACROSS MOST OF THE AREA AND RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR HAVE BEEN COMMON WITH THIS AIR MASS. ANY HEAVIER STORMS THAT REDEVELOP WILL EASILY PRODUCE SIMILAR RAINFALL RATES AND OVERWHELM NATURAL DRAINAGE. ASSUMING MOTHER NATURE COOPERATES...THE FLASH FLOOD THREAT SHOULD CONTINUE DIMINISHING THROUGH THE MORNING AND AN EXTENSION TO THE FLASH FLOOD WATCH IS NOT CURRENTLY ANTICIPATED. CONFIDENCE IN SHORT TERM FORECAST IS LOWER THAN NORMAL WITH FAIRLY SIGNIFICANT DIFFERENCES IN THE MODELS CONCERNING RAINFALL. EURO IS GENERALLY THE WETTEST OF THE MODELS WITH THE NAM BEING THE DRIEST AND THE GFS SOMEWHERE IN THE MIDDLE...THOUGH EVEN GFS ENSEMBLE MEMBERS GENERALLY INDICATE A 30 PERCENT SPREAD IN POP FORECASTS AT ANY GIVEN LOCATION FOR TODAY. GIVEN RECENT RADAR TRENDS...AM LEANING TOWARD THE LOWER POP SOLUTIONS FOR TODAY. THIS IS ALSO SUPPORTED BY THE LATEST HRRR RUNS WHICH HAVE BEEN FAIRLY ACCURATE AND CONSISTENT OVER THE PAST 8 RUNS. AM NOT QUITE AS AGGRESSIVE CLEARING THE AREA OUT AS THE HRRR WHICH CUTS OFF NEARLY ALL RAINFALL BY 15Z WITH LITTLE REDEVELOPMENT INDICATED DURING THE EARLY AFTERNOON HOURS. THOUGH THERE MAY BE A SIGNIFICANT BREAK IN THE RAIN...ESPECIALLY DURING THE LATE MORNING...BELIEVE THERE IS ENOUGH MOISTURE IN PLACE TO SEE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON HOURS SIMPLY DUE TO LIFT ASSOCIATED WITH DAYTIME HEATING. DEEP MOISTURE WILL REMAIN IN PLACE NEXT FEW DAYS AS PERSISTENT ONSHORE FLOW CONTINUES TO PUMP IN WARM AND MOIST AIR FROM THE GULF OF MEXICO. WITH WEAK AND BROAD RIDGING ALOFT AND A LACK OF ANY LARGE SCALE FORCING MECHANISM...WILL BE RELYING ON DIURNAL HEATING TO PROVIDE THE NECESSARY LIFT FOR CONVECTION. WITH TEMPS FORECAST TO TOP OUT IN THE MID TO UPPER 80S EACH DAY...THAT SHOULD BE ENOUGH TO FIRE OFF ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS SO AM CARRYING SLIGHT CHANCE TO LOW END CHANCE POPS EACH DAY THROUGH TUESDAY. BY TUESDAY...STRONG UPPER TROUGH WILL BE DIGGING INTO THE SOUTHERN PLAINS FORCING A COLD FRONT TOWARD THE AREA. MODELS CONTINUE TO STRUGGLE WITH TIMING OF THIS FRONT AND THERE IS STILL ABOUT A 12 TO 18 HOUR DIFFERENCE IN THE TIMING OF THE LOCAL FROPA. THE GFS CONTINUES TO BE THE MORE PROGRESSIVE OF THE MODELS WITH THE EURO BEING THE SLOWER SOLUTION. HAVE GENERALLY GONE WITH A BLEND... WHICH RESULTS IN A FROPA EARLY WEDNESDAY. GFS AND EURO BOTH AGREE THAT WE SHOULD SEE SOME DECENT COOLING BEHIND THIS FRONT WITH TEMPS DROPPING WELL BELOW NORMAL DURING THE OVERNIGHT HOURS WEDNESDAY NIGHT AND THURSDAY NIGHT. HIGHS WILL ALSO DROP SEVERAL DEGREES AND SHOULD TOP OUT IN THE UPPER 70S OR LOWER 80S WEDNESDAY AND THURSDAY. THESE COOLER TEMPS WILL ALSO BE ACCOMPANIED BY LOWER DEWPOINTS WHICH SHOULD MAKE THE AFTERNOONS DOWNRIGHT PLEASANT LATE IN THE WEEK IF THE FORECAST PANS OUT. AVIATION... WIDESPREAD MAINLY LIGHT TO MODERATE RAIN CONTINUES FALL ACROSS MOST OF THE FORECAST AREA EARLY THIS MORNING...AFFECTING ALL OF THE TERMINALS. MVFR CONDITIONS WILL BE THE RULE THROUGH THE EARLY MORNING HOURS WITH VFR CONDITIONS PREVAILING FROM MID MORNING ON AS THE RAINFALL ACROSS THE AREA DIMINISHES. MARINE... A RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE COASTAL WATERS WILL PERSIST THROUGH THE WEEKEND BEFORE SHIFTING EAST EARLY NEXT WEEK. A COLD FRONT WILL THEN PUSH ACROSS THE COASTAL WATERS TUESDAY NIGHT. MODERATE ONSHORE FLOW WILL GENERALLY PREVAIL THROUGH THE PERIOD IN ADVANCE OF THE COLD FRONT...WITH MODERATE OFFSHORE FLOW DEVELOPING IN ITS WAKE LATE TUESDAY NIGHT AND WEDNESDAY. DECISION SUPPORT... DSS CODE...YELLOW. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT MONITORING RIVER FLOODING DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 83 66 85 70 / 20 10 30 10 BTR 85 70 87 72 / 20 10 30 10 ASD 82 69 83 71 / 20 10 40 10 MSY 83 70 84 72 / 20 10 30 10 GPT 80 72 83 71 / 30 20 30 10 PQL 80 69 84 71 / 30 20 40 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1011 AM CDT SAT MAY 10 2014 .SOUNDING DISCUSSION... PW VALUES HAVE DROPPED FROM 2.17" AT 00Z(1900CST YESTERDAY) TO 1.68" AT 12Z THIS MORNING. THIS IS EVIDENT FROM THE DRY LAYER THAT HAS DEVELOPED BETWEEN THE SFC UP TO 850MB. YESTERDAYS SOUNDING SHOWED A VERY SHALLOW COOL POOL THAT WAS RESPONSIBLE FOR GIVING THE MUCH NEEDED INITIAL LIFT TO THE SFC PARCELS. ONCE PARCELS REACHED ~975MB OR ~1100 FEET...THE PARCEL BECAME MOIST ADIABATIC ALL THE WAY UP TO 300MB AND AT 14.5 G/KG MIXING RATIO(YES 14.5)...THESE VARIABLES POINT TO A VERY TROPICAL AIR MASS WHICH MAY HAVE CAME FROM THE DEEP MOISTURE LOADING FROM THE OLD TROPICAL SYSTEM OFF THE WEST COAST OF MEXICO. THIS MORNINGS SOUNDING DOES NOT SHOW THAT DEPTH OF MOISTURE ANY LONGER. && .PREV DISCUSSION... /ISSUED 856 AM CDT SAT MAY 10 2014/ UPDATE... SENDING UPDATED ZONES TO REMOVE HEADLINES AT TOP OF THE HOUR. FLASH FLOOD WATCH ALLOWED TO EXPRIRE AT 9 AM AS SCHEDULED. 24/RR && PREV DISCUSSION... /ISSUED 342 AM CDT SAT MAY 10 2014/ SYNOPSIS... SURFACE LOW CENTERED OVER EASTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD AND SOUTHWESTWARD THROUGH THE OHIO VALLEY AND INTO SOUTH CENTRAL MISSOURI WHERE IT HAS BECOME STATIONARY. LARGE SHIELD OF LIGHT TO MODERATE RAINFALL OVER NORTHERN GULF COAST REGION IS GRADUALLY ERODING AS OUTFLOW BOUNDARY FROM EARLIER CONVECTION HELPS CUT OFF MOISTURE SOURCE. TEMPS SITTING IN THE MID TO UPPER 60S WITH DEWPOINTS IN THE LOW TO MID 60S. DISCUSSION... HAVE CHOSEN TO LEAVE THE FLASH FLOOD WATCH IN PLACE JUST IN CASE OF ANY UNEXPECTED REDEVELOPMENT OF HEAVIER STORMS DURING THE NEXT FEW HOURS. THE GROUND IS NOW SATURATED ACROSS MOST OF THE AREA AND RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR HAVE BEEN COMMON WITH THIS AIR MASS. ANY HEAVIER STORMS THAT REDEVELOP WILL EASILY PRODUCE SIMILAR RAINFALL RATES AND OVERWHELM NATURAL DRAINAGE. ASSUMING MOTHER NATURE COOPERATES...THE FLASH FLOOD THREAT SHOULD CONTINUE DIMINISHING THROUGH THE MORNING AND AN EXTENSION TO THE FLASH FLOOD WATCH IS NOT CURRENTLY ANTICIPATED. CONFIDENCE IN SHORT TERM FORECAST IS LOWER THAN NORMAL WITH FAIRLY SIGNIFICANT DIFFERENCES IN THE MODELS CONCERNING RAINFALL. EURO IS GENERALLY THE WETTEST OF THE MODELS WITH THE NAM BEING THE DRIEST AND THE GFS SOMEWHERE IN THE MIDDLE...THOUGH EVEN GFS ENSEMBLE MEMBERS GENERALLY INDICATE A 30 PERCENT SPREAD IN POP FORECASTS AT ANY GIVEN LOCATION FOR TODAY. GIVEN RECENT RADAR TRENDS...AM LEANING TOWARD THE LOWER POP SOLUTIONS FOR TODAY. THIS IS ALSO SUPPORTED BY THE LATEST HRRR RUNS WHICH HAVE BEEN FAIRLY ACCURATE AND CONSISTENT OVER THE PAST 8 RUNS. AM NOT QUITE AS AGGRESSIVE CLEARING THE AREA OUT AS THE HRRR WHICH CUTS OFF NEARLY ALL RAINFALL BY 15Z WITH LITTLE REDEVELOPMENT INDICATED DURING THE EARLY AFTERNOON HOURS. THOUGH THERE MAY BE A SIGNIFICANT BREAK IN THE RAIN...ESPECIALLY DURING THE LATE MORNING...BELIEVE THERE IS ENOUGH MOISTURE IN PLACE TO SEE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON HOURS SIMPLY DUE TO LIFT ASSOCIATED WITH DAYTIME HEATING. DEEP MOISTURE WILL REMAIN IN PLACE NEXT FEW DAYS AS PERSISTENT ONSHORE FLOW CONTINUES TO PUMP IN WARM AND MOIST AIR FROM THE GULF OF MEXICO. WITH WEAK AND BROAD RIDGING ALOFT AND A LACK OF ANY LARGE SCALE FORCING MECHANISM...WILL BE RELYING ON DIURNAL HEATING TO PROVIDE THE NECESSARY LIFT FOR CONVECTION. WITH TEMPS FORECAST TO TOP OUT IN THE MID TO UPPER 80S EACH DAY...THAT SHOULD BE ENOUGH TO FIRE OFF ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS SO AM CARRYING SLIGHT CHANCE TO LOW END CHANCE POPS EACH DAY THROUGH TUESDAY. BY TUESDAY...STRONG UPPER TROUGH WILL BE DIGGING INTO THE SOUTHERN PLAINS FORCING A COLD FRONT TOWARD THE AREA. MODELS CONTINUE TO STRUGGLE WITH TIMING OF THIS FRONT AND THERE IS STILL ABOUT A 12 TO 18 HOUR DIFFERENCE IN THE TIMING OF THE LOCAL FROPA. THE GFS CONTINUES TO BE THE MORE PROGRESSIVE OF THE MODELS WITH THE EURO BEING THE SLOWER SOLUTION. HAVE GENERALLY GONE WITH A BLEND... WHICH RESULTS IN A FROPA EARLY WEDNESDAY. GFS AND EURO BOTH AGREE THAT WE SHOULD SEE SOME DECENT COOLING BEHIND THIS FRONT WITH TEMPS DROPPING WELL BELOW NORMAL DURING THE OVERNIGHT HOURS WEDNESDAY NIGHT AND THURSDAY NIGHT. HIGHS WILL ALSO DROP SEVERAL DEGREES AND SHOULD TOP OUT IN THE UPPER 70S OR LOWER 80S WEDNESDAY AND THURSDAY. THESE COOLER TEMPS WILL ALSO BE ACCOMPANIED BY LOWER DEWPOINTS WHICH SHOULD MAKE THE AFTERNOONS DOWNRIGHT PLEASANT LATE IN THE WEEK IF THE FORECAST PANS OUT. AVIATION... WIDESPREAD MAINLY LIGHT TO MODERATE RAIN CONTINUES FALL ACROSS MOST OF THE FORECAST AREA EARLY THIS MORNING...AFFECTING ALL OF THE TERMINALS. MVFR CONDITIONS WILL BE THE RULE THROUGH THE EARLY MORNING HOURS WITH VFR CONDITIONS PREVAILING FROM MID MORNING ON AS THE RAINFALL ACROSS THE AREA DIMINISHES. MARINE... A RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE COASTAL WATERS WILL PERSIST THROUGH THE WEEKEND BEFORE SHIFTING EAST EARLY NEXT WEEK. A COLD FRONT WILL THEN PUSH ACROSS THE COASTAL WATERS TUESDAY NIGHT. MODERATE ONSHORE FLOW WILL GENERALLY PREVAIL THROUGH THE PERIOD IN ADVANCE OF THE COLD FRONT...WITH MODERATE OFFSHORE FLOW DEVELOPING IN ITS WAKE LATE TUESDAY NIGHT AND WEDNESDAY. DECISION SUPPORT... DSS CODE...YELLOW. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT MONITORING RIVER FLOODING DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 83 66 85 70 / 20 10 30 10 BTR 85 70 87 72 / 20 10 30 10 ASD 82 69 83 71 / 40 20 40 10 MSY 83 70 84 72 / 40 20 30 10 GPT 80 72 83 71 / 50 20 30 10 PQL 80 69 84 71 / 50 30 40 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS NEW ORLEANS LA
856 AM CDT SAT MAY 10 2014 .UPDATE... SENDING UPDATED ZONES TO REMOVE HEADLINES AT TOP OF THE HOUR. FLASH FLOOD WATCH ALLOWED TO EXPRIRE AT 9 AM AS SCHEDULED. 24/RR && .DECISION SUPPORT... DSS CODE...BLUE. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT MONITORING RIVER FLOODING DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PREV DISCUSSION... /ISSUED 342 AM CDT SAT MAY 10 2014/ SYNOPSIS... SURFACE LOW CENTERED OVER EASTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD AND SOUTHWESTWARD THROUGH THE OHIO VALLEY AND INTO SOUTH CENTRAL MISSOURI WHERE IT HAS BECOME STATIONARY. LARGE SHIELD OF LIGHT TO MODERATE RAINFALL OVER NORTHERN GULF COAST REGION IS GRADUALLY ERODING AS OUTFLOW BOUNDARY FROM EARLIER CONVECTION HELPS CUT OFF MOISTURE SOURCE. TEMPS SITTING IN THE MID TO UPPER 60S WITH DEWPOINTS IN THE LOW TO MID 60S. DISCUSSION... HAVE CHOSEN TO LEAVE THE FLASH FLOOD WATCH IN PLACE JUST IN CASE OF ANY UNEXPECTED REDEVELOPMENT OF HEAVIER STORMS DURING THE NEXT FEW HOURS. THE GROUND IS NOW SATURATED ACROSS MOST OF THE AREA AND RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR HAVE BEEN COMMON WITH THIS AIR MASS. ANY HEAVIER STORMS THAT REDEVELOP WILL EASILY PRODUCE SIMILAR RAINFALL RATES AND OVERWHELM NATURAL DRAINAGE. ASSUMING MOTHER NATURE COOPERATES...THE FLASH FLOOD THREAT SHOULD CONTINUE DIMINISHING THROUGH THE MORNING AND AN EXTENSION TO THE FLASH FLOOD WATCH IS NOT CURRENTLY ANTICIPATED. CONFIDENCE IN SHORT TERM FORECAST IS LOWER THAN NORMAL WITH FAIRLY SIGNIFICANT DIFFERENCES IN THE MODELS CONCERNING RAINFALL. EURO IS GENERALLY THE WETTEST OF THE MODELS WITH THE NAM BEING THE DRIEST AND THE GFS SOMEWHERE IN THE MIDDLE...THOUGH EVEN GFS ENSEMBLE MEMBERS GENERALLY INDICATE A 30 PERCENT SPREAD IN POP FORECASTS AT ANY GIVEN LOCATION FOR TODAY. GIVEN RECENT RADAR TRENDS...AM LEANING TOWARD THE LOWER POP SOLUTIONS FOR TODAY. THIS IS ALSO SUPPORTED BY THE LATEST HRRR RUNS WHICH HAVE BEEN FAIRLY ACCURATE AND CONSISTENT OVER THE PAST 8 RUNS. AM NOT QUITE AS AGGRESSIVE CLEARING THE AREA OUT AS THE HRRR WHICH CUTS OFF NEARLY ALL RAINFALL BY 15Z WITH LITTLE REDEVELOPMENT INDICATED DURING THE EARLY AFTERNOON HOURS. THOUGH THERE MAY BE A SIGNIFICANT BREAK IN THE RAIN...ESPECIALLY DURING THE LATE MORNING...BELIEVE THERE IS ENOUGH MOISTURE IN PLACE TO SEE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON HOURS SIMPLY DUE TO LIFT ASSOCIATED WITH DAYTIME HEATING. DEEP MOISTURE WILL REMAIN IN PLACE NEXT FEW DAYS AS PERSISTENT ONSHORE FLOW CONTINUES TO PUMP IN WARM AND MOIST AIR FROM THE GULF OF MEXICO. WITH WEAK AND BROAD RIDGING ALOFT AND A LACK OF ANY LARGE SCALE FORCING MECHANISM...WILL BE RELYING ON DIURNAL HEATING TO PROVIDE THE NECESSARY LIFT FOR CONVECTION. WITH TEMPS FORECAST TO TOP OUT IN THE MID TO UPPER 80S EACH DAY...THAT SHOULD BE ENOUGH TO FIRE OFF ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS SO AM CARRYING SLIGHT CHANCE TO LOW END CHANCE POPS EACH DAY THROUGH TUESDAY. BY TUESDAY...STRONG UPPER TROUGH WILL BE DIGGING INTO THE SOUTHERN PLAINS FORCING A COLD FRONT TOWARD THE AREA. MODELS CONTINUE TO STRUGGLE WITH TIMING OF THIS FRONT AND THERE IS STILL ABOUT A 12 TO 18 HOUR DIFFERENCE IN THE TIMING OF THE LOCAL FROPA. THE GFS CONTINUES TO BE THE MORE PROGRESSIVE OF THE MODELS WITH THE EURO BEING THE SLOWER SOLUTION. HAVE GENERALLY GONE WITH A BLEND... WHICH RESULTS IN A FROPA EARLY WEDNESDAY. GFS AND EURO BOTH AGREE THAT WE SHOULD SEE SOME DECENT COOLING BEHIND THIS FRONT WITH TEMPS DROPPING WELL BELOW NORMAL DURING THE OVERNIGHT HOURS WEDNESDAY NIGHT AND THURSDAY NIGHT. HIGHS WILL ALSO DROP SEVERAL DEGREES AND SHOULD TOP OUT IN THE UPPER 70S OR LOWER 80S WEDNESDAY AND THURSDAY. THESE COOLER TEMPS WILL ALSO BE ACCOMPANIED BY LOWER DEWPOINTS WHICH SHOULD MAKE THE AFTERNOONS DOWNRIGHT PLEASANT LATE IN THE WEEK IF THE FORECAST PANS OUT. AVIATION... WIDESPREAD MAINLY LIGHT TO MODERATE RAIN CONTINUES FALL ACROSS MOST OF THE FORECAST AREA EARLY THIS MORNING...AFFECTING ALL OF THE TERMINALS. MVFR CONDITIONS WILL BE THE RULE THROUGH THE EARLY MORNING HOURS WITH VFR CONDITIONS PREVAILING FROM MID MORNING ON AS THE RAINFALL ACROSS THE AREA DIMINISHES. MARINE... A RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE COASTAL WATERS WILL PERSIST THROUGH THE WEEKEND BEFORE SHIFTING EAST EARLY NEXT WEEK. A COLD FRONT WILL THEN PUSH ACROSS THE COASTAL WATERS TUESDAY NIGHT. MODERATE ONSHORE FLOW WILL GENERALLY PREVAIL THROUGH THE PERIOD IN ADVANCE OF THE COLD FRONT...WITH MODERATE OFFSHORE FLOW DEVELOPING IN ITS WAKE LATE TUESDAY NIGHT AND WEDNESDAY. DECISION SUPPORT... DSS CODE...YELLOW. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT MONITORING RIVER FLOODING DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 83 66 85 70 / 20 10 30 10 BTR 85 70 87 72 / 20 10 30 10 ASD 82 69 83 71 / 40 20 40 10 MSY 83 70 84 72 / 40 20 30 10 GPT 80 72 83 71 / 50 20 30 10 PQL 80 69 84 71 / 50 30 40 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$ 24/RR
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
342 AM CDT SAT MAY 10 2014 .SYNOPSIS... SURFACE LOW CENTERED OVER EASTERN ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD AND SOUTHWESTWARD THROUGH THE OHIO VALLEY AND INTO SOUTH CENTRAL MISSOURI WHERE IT HAS BECOME STATIONARY. LARGE SHIELD OF LIGHT TO MODERATE RAINFALL OVER NORTHERN GULF COAST REGION IS GRADUALLY ERODING AS OUTFLOW BOUNDARY FROM EARLIER CONVECTION HELPS CUT OFF MOISTURE SOURCE. TEMPS SITTING IN THE MID TO UPPER 60S WITH DEWPOINTS IN THE LOW TO MID 60S. && .DISCUSSION... HAVE CHOSEN TO LEAVE THE FLASH FLOOD WATCH IN PLACE JUST IN CASE OF ANY UNEXPECTED REDEVELOPMENT OF HEAVIER STORMS DURING THE NEXT FEW HOURS. THE GROUND IS NOW SATURATED ACROSS MOST OF THE AREA AND RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR HAVE BEEN COMMON WITH THIS AIR MASS. ANY HEAVIER STORMS THAT REDEVELOP WILL EASILY PRODUCE SIMILAR RAINFALL RATES AND OVERWHELM NATURAL DRAINAGE. ASSUMING MOTHER NATURE COOPERATES...THE FLASH FLOOD THREAT SHOULD CONTINUE DIMINISHING THROUGH THE MORNING AND AN EXTENSION TO THE FLASH FLOOD WATCH IS NOT CURRENTLY ANTICIPATED. CONFIDENCE IN SHORT TERM FORECAST IS LOWER THAN NORMAL WITH FAIRLY SIGNIFICANT DIFFERENCES IN THE MODELS CONCERNING RAINFALL. EURO IS GENERALLY THE WETTEST OF THE MODELS WITH THE NAM BEING THE DRIEST AND THE GFS SOMEWHERE IN THE MIDDLE...THOUGH EVEN GFS ENSEMBLE MEMBERS GENERALLY INDICATE A 30 PERCENT SPREAD IN POP FORECASTS AT ANY GIVEN LOCATION FOR TODAY. GIVEN RECENT RADAR TRENDS...AM LEANING TOWARD THE LOWER POP SOLUTIONS FOR TODAY. THIS IS ALSO SUPPORTED BY THE LATEST HRRR RUNS WHICH HAVE BEEN FAIRLY ACCURATE AND CONSISTENT OVER THE PAST 8 RUNS. AM NOT QUITE AS AGGRESSIVE CLEARING THE AREA OUT AS THE HRRR WHICH CUTS OFF NEARLY ALL RAINFALL BY 15Z WITH LITTLE REDEVELOPMENT INDICATED DURING THE EARLY AFTERNOON HOURS. THOUGH THERE MAY BE A SIGNIFICANT BREAK IN THE RAIN...ESPECIALLY DURING THE LATE MORNING...BELIEVE THERE IS ENOUGH MOISTURE IN PLACE TO SEE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON HOURS SIMPLY DUE TO LIFT ASSOCIATED WITH DAYTIME HEATING. DEEP MOISTURE WILL REMAIN IN PLACE NEXT FEW DAYS AS PERSISTENT ONSHORE FLOW CONTINUES TO PUMP IN WARM AND MOIST AIR FROM THE GULF OF MEXICO. WITH WEAK AND BROAD RIDGING ALOFT AND A LACK OF ANY LARGE SCALE FORCING MECHANISM...WILL BE RELYING ON DIURNAL HEATING TO PROVIDE THE NECESSARY LIFT FOR CONVECTION. WITH TEMPS FORECAST TO TOP OUT IN THE MID TO UPPER 80S EACH DAY...THAT SHOULD BE ENOUGH TO FIRE OFF ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS SO AM CARRYING SLIGHT CHANCE TO LOW END CHANCE POPS EACH DAY THROUGH TUESDAY. BY TUESDAY...STRONG UPPER TROUGH WILL BE DIGGING INTO THE SOUTHERN PLAINS FORCING A COLD FRONT TOWARD THE AREA. MODELS CONTINUE TO STRUGGLE WITH TIMING OF THIS FRONT AND THERE IS STILL ABOUT A 12 TO 18 HOUR DIFFERENCE IN THE TIMING OF THE LOCAL FROPA. THE GFS CONTINUES TO BE THE MORE PROGRESSIVE OF THE MODELS WITH THE EURO BEING THE SLOWER SOLUTION. HAVE GENERALLY GONE WITH A BLEND... WHICH RESULTS IN A FROPA EARLY WEDNESDAY. GFS AND EURO BOTH AGREE THAT WE SHOULD SEE SOME DECENT COOLING BEHIND THIS FRONT WITH TEMPS DROPPING WELL BELOW NORMAL DURING THE OVERNIGHT HOURS WEDNESDAY NIGHT AND THURSDAY NIGHT. HIGHS WILL ALSO DROP SEVERAL DEGREES AND SHOULD TOP OUT IN THE UPPER 70S OR LOWER 80S WEDNESDAY AND THURSDAY. THESE COOLER TEMPS WILL ALSO BE ACCOMPANIED BY LOWER DEWPOINTS WHICH SHOULD MAKE THE AFTERNOONS DOWNRIGHT PLEASANT LATE IN THE WEEK IF THE FORECAST PANS OUT. && .AVIATION... WIDESPREAD MAINLY LIGHT TO MODERATE RAIN CONTINUES FALL ACROSS MOST OF THE FORECAST AREA EARLY THIS MORNING...AFFECTING ALL OF THE TERMINALS. MVFR CONDITIONS WILL BE THE RULE THROUGH THE EARLY MORNING HOURS WITH VFR CONDITIONS PREVAILING FROM MID MORNING ON AS THE RAINFALL ACROSS THE AREA DIMINISHES. && .MARINE... A RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE COASTAL WATERS WILL PERSIST THROUGH THE WEEKEND BEFORE SHIFTING EAST EARLY NEXT WEEK. A COLD FRONT WILL THEN PUSH ACROSS THE COASTAL WATERS TUESDAY NIGHT. MODERATE ONSHORE FLOW WILL GENERALLY PREVAIL THROUGH THE PERIOD IN ADVANCE OF THE COLD FRONT...WITH MODERATE OFFSHORE FLOW DEVELOPING IN ITS WAKE LATE TUESDAY NIGHT AND WEDNESDAY. && .DECISION SUPPORT... DSS CODE...YELLOW. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT MONITORING RIVER FLOODING DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 83 66 85 70 / 40 10 30 10 BTR 85 70 87 72 / 40 10 30 10 ASD 82 69 83 71 / 60 20 40 10 MSY 83 70 84 72 / 60 20 30 10 GPT 80 72 83 71 / 70 20 30 10 PQL 80 69 84 71 / 70 30 40 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH UNTIL 9 AM SATURDAY FOR THE FOLLOWING ZONES: ASCENSION...ASSUMPTION...EAST BATON ROUGE...EAST FELICIANA...IBERVILLE...LIVINGSTON...LOWER JEFFERSON...LOWER LAFOURCHE...LOWER PLAQUEMINES...LOWER ST. BERNARD...LOWER TERREBONNE...NORTHERN TANGIPAHOA...ORLEANS...POINTE COUPEE...SOUTHERN TANGIPAHOA...ST. CHARLES...ST. HELENA...ST. JAMES...ST. JOHN THE BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER TERREBONNE...WASHINGTON...WEST BATON ROUGE...AND WEST FELICIANA. GM...NONE. MS...FLASH FLOOD WATCH UNTIL 9 AM SATURDAY FOR THE FOLLOWING ZONES: AMITE...HANCOCK...HARRISON...JACKSON...PEARL RIVER...PIKE...WALTHALL...AND WILKINSON. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
650 PM EDT SAT MAY 10 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA TONIGHT. A BACKDOOR COLD FRONT WILL MOVE IN FROM THE NORTHEAST SUNDAY NIGHT AND MONDAY WITH COOLER TEMPERATURES AND A CHANCE OF SHOWERS. HIGH PRESSURE BUILDS IN TUESDAY AND TUESDAY NIGHT BEFORE MOIST SOUTHERLY FLOW RETURNS MID TO LATE WEEK.&& .NEAR TERM /THROUGH SUNDAY/... UPDATE: NOT MUCH HAPPENING ACROSS THE AREA AS SHOWERS/STORMS HAVING A TUF TIME GETTING ORGANIZED. AN ISOLD SHOWER PAST HR MOVD THRU PQI AND NOW INTO WRN NB W/ JUST SOME LGT TO BRIEFLY MDT RAIN RPTD. HRRR SUGGESTS SOME SHOWERS/STORMS CURRENTLY NW OF THE AREA MAY BUILD SWWRD AND MOVE ACROSS OUR NRN AREAS LATER THIS EVE. HAVE ADJUSTED POPS/WX TO BETTER REFLECT CURRENT AND EXPECTED TRENDS... PREV DISC: CLEARING OVER WESTERN MAINE AND THE QUEBEC EASTERN TOWNSHIPS HAS ALLOWED FOR DESTABILIZING AHEAD OF THE SURFACE COLD FRONT, WITH CONVECTION. EXPECT SCATTERED SHOWERS AND STORMS MAINLY OVER NORTHERN AND CENTRAL PORTIONS OF THE AREA, WITH STRONG WINDS BEING THE PRIMARY THREAT WITH THE STORMS. DO NOT EXPECT ANYTHING SEVERE. WEAK COLD FRONT PASSES THROUGH THIS EVENING AND DRIER AIR MOVES IN. FOR SUNDAY, WITH WESTERLY FLOW OVER THE AREA, LOOK FOR A PARTLY CLOUDY, BREEZY, AND WARM DAY DOWNEAST, BUT MOSTLY CLOUDY OVER THE NORTH WITH A CHANCE OF SHOWERS AS A BACKDOOR COLD FRONT APPROACHES FROM THE NORTHEAST. THIS COLD FRONT WILL MOVE INTO NORTHEASTERN MAINE IN THE EVENING. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... CYCLONIC FLOW ALOFT WITH EMBEDDED SHORTWAVES WILL AFFECT OUR FCST AREA THROUGH MOST OF THE SHORT TERM PERIOD. THIS WILL KEEP MUCH OF THE AREA UNDER A CHANCE OF SHOWERS SUNDAY NIGHT THROUGH MONDAY. FINALLY ON MONDAY NIGHT AND TUESDAY...CONDITIONS WILL BECOME MOSTLY DRY BUT SEASONALLY COOL AS A RIDGE OF HIGH PRESSURE BUILDS ACROSS THE NORTHEAST. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... THE AFOREMENTIONED RIDGE WILL GRADUALLY DRIFT EWD THROUGH THE EARLY PART OF THE EXTENDED FCST PERIOD. BY THE WED/TUES TIME FRAME...MORE UNSETTLED CONDITIONS WILL DEVELOP ACROSS OUR WRN ZONES IN RESPONSE TO RETURN SRLY FLOW AHEAD OF AN APPROACHING COLD FRONT. THE MEDIUM RANGE MODEL THEN DIVERGE IN THEIR SOLUTIONS FOR FRIDAY INTO SATURDAY OF NEXT WEEK...WITH THE GFS BEING MORE AGGRESSIVE BRINGING LOW FROM THE SOUTHWEST ACROSS NEW ENGLAND WITH WIDESPREAD PRECIP. THE ECMWF IS SLOWER WITH NO LOW DEVELOPING ALONG THE MID-ATLANTIC. THE COLD FRONT IS EXPECTED MOVE OVER THE CWA ON SATURDAY...BEFORE WASHING OUT. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... NEAR TERM: LATE THIS AFTERNOON, EXPECT ANY REMAINING IFR TO DISSIPATE FROM WEST TO EAST. GENERALLY VFR LATE AFTERNOON INTO OVERNIGHT HOURS, ALTHOUGH SCATTERED STORMS LATE THIS AFTERNOON COULD LEAD TO LOCALLY GUSTY WINDS AND BRIEF MVFR CONDITIONS. MAINLY VFR ON SUNDAY, ALTHOUGH A FRONT MOVING INTO NORTHERN MAINE LATE IN THE AFTERNOON COULD LEAD TO MVFR CEILINGS EITHER LATE SUNDAY AFTERNOON OR SUNDAY NIGHT. WINDS WILL BE FAIRLY GUSTY OUT OF THE WEST ON SUNDAY. SHORT TERM: MVFR CEILINGS POSSIBLE SUNDAY NIGHT INTO MONDAY, MAINLY NORTH OF BANGOR. CLEARING WITH VFR FOR TUESDAY. && .MARINE... NEAR TERM: SOUTH WINDS WILL DIMINISH TO BELOW SMALL CRAFT LEVELS THIS EVENING, WITH SEAS FALLING BELOW SMALL CRAFT LEVELS (5 FEET) AROUND DAYBREAK SUNDAY. WINDS SWITCH TO OFFSHORE FOR SUNDAY, AND MAY PICK UP TO SMALL CRAFT CONDITIONS IN THE AFTERNOON. SHORT TERM: WINDS AND WAVES WILL INCREASE FOR THE SHORT TERM...POSSIBLY REACHING MARGINAL SMALL CRAFT ADVISORY LEVELS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ050-051. && $$ NEAR TERM...KHW/FOISY SHORT TERM...RB LONG TERM...RB AVIATION...KHW MARINE...KHW/FOISY/RB
AREA FORECAST DISCUSSION
NWS GRAY ME
254 PM EDT SAT MAY 10 2014 .SYNOPSIS... A COLD FRONT WILL STALL BRIEFLY OFFSHORE TONIGHT. HIGH PRESSURE WILL BUILD IN FOR SUNDAY AND MONDAY. A BACK DOOR COLD FRONT TRACKS SOUTHWEST ACROSS THE AREA MONDAY NIGHT AND TUESDAY MORNING. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHEAST THROUGH WEDNESDAY. A SLOW MOVING COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY AND CROSS THE AREA FRIDAY. HIGH PRESSURE WILL ENTER THE REGION NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... CLOUDS AND FOG ARE HANGING IN TOUGH OVER EASTERN AREAS LATE THIS AFTERNOON. OTHERWISE...CLEARING AND SOMEWHAT DRIER AIR CONTINUES TO MOVE IN FROM THE WEST. THERE IS CONVECTION OVER SOUTHERN NYS WHICH WILL CONTINUE TO MOVE ENE PER LATEST HRRR MODEL RUN. CONVECTION MAY BRIEFLY REACH SOUTHERNMOST PORTIONS OF THE FORECAST AREA THIS EVENING...AND HAVE INCLUDED CHC POPS FOR THIS REGION FOR A COUPLE HOURS. OTHERWISE...THERE APPEARS TO BE SUFFICIENT GRADIENT OVERNIGHT TO KEEP FOG FROM FORMING. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... OFFSHORE FLOW WILL ALLOW FOR WARM TEMPERATURES ON SUNDAY FOR ALL AREAS. THIS WILL BRING TEMPERATURES IN THE 70S FOR MANY SECTIONS...THE FIRST TIME IN QUITE A PERIOD. CYCLONIC FLOW MAY INDUCE A COUPLE SHOWERS OVER THE FAR NRN MOUNTAINS DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. IT WILL BE DRY SUNDAY NIGHT. HOWEVER...A BACK DOOR COLD FRONT MAY BE APPROACHING THE REGION...RETROGRADING INTO OUR AREA FROM NORTHEAST TO SOUTHWEST. && .LONG TERM /MONDAY THROUGH SATURDAY/... MODELS ARE IN GOOD AGREEMENT THROUGH LATE NEXT WEEK ON LONGWAVE PATTERN. THE UPPER TROUGH OVER NEW ENGLAND IS LIFTING OUT AS WE BEGIN THE PERIOD ON MONDAY WITH UPPER RIDGE PROGRESSING EASTWARD INTO THE REGION THROUGH MIDWEEK BEFORE SLIDING OFFSHORE BY THURSDAY. AN UNUSUALLY DEEP TROUGH FOR THIS TIME OF YEAR THEN ARRIVES BY LATE IN THE WEEK BEFORE CLOSING OFF OVER THE GREAT LAKES. OVERALL...EXPECT ONE WELL ABOVE NORMAL DAY MONDAY FOLLOWED BY SEVERAL DAYS OF WELL BELOW NORMAL TEMPERATURES AS FLOW TURNS ONSHORE. IN THE DAILIES...WE BEGIN THE PERIOD WITH A FRONT STALLED TO OUR SOUTH AND WEST AS HIGH PRESSURE BUILDS BY TO OUR NORTH...BEFORE THE HIGH SLIDES OFFSHORE ON WEDNESDAY. A WARM WESTERLY FLOW ON MONDAY IS REPLACED BY A COOL ONSHORE FLOW FOR TUESDAY AND WEDNESDAY. WHILE THE RIDGE WILL KEEP THE FRONT STALLED TO OUR WEST THROUGH WEDNESDAY...THE PERSISTENT ONSHORE FLOW MAY EVENTUALLY PRODUCE MARINE STRATUS AND DRIZZLE BY TUESDAY NIGHT OR WEDNESDAY. WE BECOME INCREASINGLY UNSETTLED AFTER THAT AS THE FRONTAL BOUNDARY MEANDERS EASTWARD AND THE UPPER TROUGH CLOSES OFF TO OUR WEST. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SHORT TERM...LOCAL LIFR CONDITIONS EARLY EAST...OTHERWISE IMPROVING TO VFR. LONG TERM... WED - THU...AREAS OF MVFR IN MARINE STRATUS WITH LCL IFR POSSIBLE IN FOG AND DRIZZLE. && .MARINE... SHORT TERM...SCA TO REMAIN IN EFFECT FOR SEAS. LONG TERM... TUE - THU...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .FIRE WEATHER... SHOWERS TODAY HAVE LEFT HUMIDITY LEVELS HIGH AND FIRE CONCERNS LOW. HOWEVER...DRIER CONDITIONS RETURN ON SUNDAY. WITH DEEP MIXING THE HUMIDITY LEVELS WILL FALL TO 25 TO 30 PERCENT ON THE COASTAL SIDE OF THE MOUNTAINS DURING THE AFTERNOON SUNDAY ALONG WITH WINDS GUSTING TO 20 MPH. THIS BORDERLINES BUT DOES NOT EXCEED RED FLAG WARNING CONDITIONS. SOME WETTING TODAY HAS HELPED FUEL CONDITIONS WILL BE COORDINATING WITH MAINE LATER TODAY. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ150-152. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ154. && $$
AREA FORECAST DISCUSSION
NWS GRAY ME
952 AM EDT SAT MAY 10 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA THIS AFTERNOON...WHICH WILL STALL BRIEFLY OFFSHORE TONIGHT. HIGH PRESSURE WILL BUILD IN FOR SUNDAY AND MONDAY. A BACK DOOR COLD FRONT TRACKS SOUTHWEST ACROSS THE AREA MONDAY NIGHT AND TUESDAY MORNING. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHEAST THROUGH WEDNESDAY. A SLOW MOVING COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY AND CROSS THE AREA FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 1347Z UPDATE...HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. LOW CLOUDS...FOG AND SHOWERS CONTINUE ACROSS PORTIONS OF THE FORECAST AREA. THERE ARE ALSO A FEW LIGHTNING STROKES ALONG THE COAST AND THE OFFSHORE WATERS WHICH WILL LAST FOR ANOTHER HOUR OR TWO. LATEST HRRR RUN CONTINUES TO SHOW THIS PRECIPITATION EXITING EASTERN PORTIONS OF THE FORECAST AREA BY AROUND 18Z. CLEARING TO TAKE PLACE THIS AFTERNOON...HOWEVER THE PRECISE TIME OF THIS...ESPECIALLY ALONG THE COAST WILL BE CHALLENGING. LATEST STLT IMAGERY CONTINUES TO SHOW A SHARP CLEARING LINE OVER VERMONT AND EASTERNMOST NYS. COASTAL LOW CLOUDS WILL HANG ON TOUGH THROUGH EARLY THIS AFTERNOON HOWEVER...ESPECIALLY AS YOU HEAD EAST TOWARDS PENOBSCOT BAY. PREV DISC... RAIN HAS MOVED INTO NORTHERN/CENTRAL NEW HAMPSHIRE AND NORTHWEST MAINE. THIS SHOULD CONTINUE FOR ABOUT 3 HOURS BEFORE ENDING FROM WEST TO EAST. THE BACK EDGE OF THIS PRECIPITATION IS ALREADY VISIBLE ON REGIONAL RADAR IMAGERY IN NEW YORK STATE... WITH A TRACK SET TO ARRIVE IN NEW HAMPSHIRE AT ABOUT 10AM. HAVE ADJUSTED POP FORECAST TO BETTER REFLECT CERTAINTY OF PRECIPITATION ACROSS MUCH OF NORTHERN AREAS AS WELL AS TIMING OF ARRIVAL AND DEPARTURE OF THE AREA OF RAIN. NO OTHER CHANGES WERE MADE TO THE FORECAST. ORIGINAL DISCUSSION... AS THE RIDGE GRADUALLY SHIFTS EAST THIS MORNING... IT WILL BE REPLACED BY A SHORTWAVE TROUGH MOVING OUT OF THE GREAT LAKES. THIS TROUGH IS ALREADY PRODUCING WIDESPREAD SHOWERS ACROSS UPSTATE NEW YORK. THIS SHOWER ACTIVITY WILL SPREAD ACROSS NEW HAMPSHIRE AND MAINE DURING THE MORNING HOURS AHEAD OF THE FRONT. AN ISOLATED THUNDERSTORM IS POSSIBLE AS WELL. EXPECT SHOWERS TO END FROM WEST TO EAST DURING THE MORNING TO EARLY AFTERNOON. WINDS BEHIND THE FRONT SHIFT TO THE WEST AND CLOUDS WILL CLEAR OUT. TEMPERATURES WILL WARM INTO THE 70S... THOUGH NEAR THE COAST FROM PORTLAND EASTWARD MAY STAY IN THE 60S. PARTS OF SOUTHERN AND CENTRAL NEW HAMPSHIRE COULD GET CLOSE TO 80 DEGREES. IF PORTLAND REACHES 70 DEGREES IT WILL BE THE FIRST TIME THIS YEAR. THAT IS ABOUT 3 WEEKS LATER THAN NORMAL FOR THE FIRST 70 DEGREE DAY. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... ANOTHER SHORTWAVE TROUGH WILL TRACK THROUGH THE MID ATLANTIC AND SOUTHERN NEW ENGLAND TONIGHT. THIS IS EXPECTED TO PRODUCE SHOWERS OVERNIGHT. SOUTHERN NEW HAMPSHIRE AND COASTAL MAINE MAY BE BRUSHED BY A FEW SHOWERS OVERNIGHT FROM THIS FEATURE BUT MOST OF THE AREA WILL REMAIN DRY. TEMPERATURES BOTTOM OUT IN THE 40S AND 50S. SHOULD BE ANOTHER MOSTLY SUNNY AND WARM DAY ON SUNDAY. WARM/DRY AIR ALOFT WILL ALLOW FOR GOOD MIXING WITH WINDS GUSTING AS HIGH AS 25 MPH. THIS SHOULD BE ENOUGH TO PREVENT THE SEA BREEZE FROM REACHING THE COAST... AND THUS EVEN COASTAL AREAS SHOULD SEE 70+ DEGREES ON SUNDAY. && .LONG TERM /MONDAY THROUGH FRIDAY/... SURFACE RIDGE LOOKS TO HOLD SUNDAY NIGHT INTO AT LEAST PART OF THE DAY ON MONDAY...WHICH WILL MAKE FOR ANOTHER WARM AND GENERALLY FAIR DAY...ALTHOUGH WILL HAVE TO WATCH FOR INCREASED CLOUDS OR SHOWERS IN NE ZONES IN THE AFTERNOON AS WEAK WAVE AT 500 MB...AND BACK DOOR SURFACE COLD FRONT APPROACHES. IN AND OF ITSELF THIS BACK DOOR COLD FRONT IS NOT THAT IMPRESSIVE...BUT MODELS WANT TO BRING A REMNANT MCS-LIKE SYSTEM OVER THE TOP OF THE RIDGE ASSOCIATED WITH MID LEVEL JET MAX. THIS COMBINATION INCREASES THE CHANCES OF SHOWERS ACROSS THE FORECAST AREA MONDAY NIGHT INTO EARLY TUESDAY. ONCE THE SYSTEMS CLEAR OUT OF THE AREA TUESDAY...COOLER SURFACE HIGH BUILDS SOUTHWARD...AND WE WILL SEE SOME CLEARING WITH HIGHS THE 60S TUESDAY INTO WEDNESDAY. 500MB PATTERN BECOMES QUITE AMPLIFIED BY WEDNESDAY...AS 500MB CLOSED LOW DEVELOPS TO THE WEST...AND RIDGE AMPLIFIES TO THE EAST. THIS WILL PRODUCE A SLOW MOVING COLD FRONT TO OUR WEST WHICH WILL TRACK SLOWLY TO THE EAST THURSDAY-FRIDAY AND WILL BRING A THREAT OF SHOWERS...ALTHOUGH MODELS CONTINUE TO PROLONG THE ARRIVAL OF THE FRONT...WHICH LOOKS TO BE LATE FRIDAY OR SATURDAY AT THIS POINT...WHICH WOULD BE THE BEST SHOT FOR RAIN. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM... IFR CEILINGS AND SHOWERS CONTINUE THROUGH THE MORNING. WINDS SHIFT TO THE WEST BEHIND A FRONT LATE IN THE MORNING OR EARLY AFTERNOON. THIS SHOULD BE ENOUGH TO CLEAR OUT THE LOW CLOUDS AND BRING CONDITIONS BACK TO VFR. VFR CONTINUES ON SUNDAY WITH GUSTY NORTHWEST WINDS. LONG TERM... MAINLY VFR SUNDAY NIGHT THRU WEDNESDAY. SOME POSSIBLE FLIGHT RESTRICTIONS MONDAY NIGHT IN SHOWERS. && .MARINE... SHORT TERM... SMALL CRAFT ADVISORY FOR PENOBSCOT BAY WAS DROPPED AS WAVE HEIGHTS ARE NOT EXPECTED TO REACH 5 FEET INSIDE THE ISLANDS. THE SOUTHERLY FLOW TODAY WILL PROVIDE A LONG ENOUGH FETCH TO PRODUCE WAVE HEIGHTS OF 5 TO 7 FEET OVER THE OUTER WATERS... ESPECIALLY IN THE EASTERN WATERS. WINDS SHIFT TO THE WEST THIS EVENING BEHIND THE FRONT. WAVE HEIGHTS SHOULD FALL BELOW 5 FEET AGAIN OVERNIGHT. LONG TERM...SCA CONDITIONS NOT EXPECTED SUNDAY NIGHT THRU WEDNESDAY. && .FIRE WEATHER... SHOWERS TODAY WILL KEEP HUMIDITY LEVELS HIGH AND FIRE CONCERNS LOW. HOWEVER... DRIER CONDITIONS RETURN ON SUNDAY. WITH DEEP MIXING THE HUMIDITY LEVELS WILL FALL TO 20 TO 30 PERCENT ON THE COASTAL SIDE OF THE MOUNTAINS DURING THE AFTERNOON SUNDAY ALONG WITH WINDS GUSTING TO 25 MPH. THIS COULD WARRANT A RED FLAG WARNING DEPENDING ON FUEL CONDITIONS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ150-152. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ154. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
612 AM EDT SAT MAY 10 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION LATER TODAY INTO TONIGHT. AN UPPER LEVEL DISTURBANCE IS EXPECTED TO SLIDE ACROSS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... 615 AM UPDATE...MINOR ADJUSTMENTS TO HRLY TEMPS...OTHERWISE PREVIOUS FORECAST REMAINS ON TRACK. PREVIOUS DISCUSSION...THE UPPER RIDGE SHIFT EAST OF THE AREA AS THE COLD FRONT MOVES ACROSS NH. PARTIAL CLEARING THIS MORNING INTO THE EARLY AFTERNOON IN THE WARM SECTOR COULD ALLOW FOR SOME THUNDERSTORM ACTIVITY ACROSS INTERIOR DOWNEAST AND THE INTERIOR HIGH LANDS TOMORROW AFTERNOON IN ADVANCE OF THE APPROACHING COLD FRONT. THE COLD FRONT WILL MOVE THROUGH LATE AFTERNOON EARLY IN THE EVENING. HIGHER PRESSURE WILL BUILD IN BEHIND THE COLD FRONT AND WILL DOMINATE THROUGH THE END OF THE PERIOD. LOADED HRRR FOR SKY/POP GRIDS THROUGH 12Z USED A BLEND OF NAM/GEM/GFS/ECMWF FOR BALANCE OF PERIOD. LOADED NAM/GEM/GFS/ECMWF FOR HRLY TEMP/DP/WNDS. HPC GUIDANCE FOR QPF. ADDED 15 PERCENT TO WNDS FOR GUSTS OVER LAND...20 PERCENT OVER WATER. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UNSETTLED CONDITIONS IN MONDAY WITH A BLOCKING PATTERN IN PLACE. A SFC TROF IS FORECAST TO SWING ACROSS THE REGION ON SUNDAY. BEST UPPER LEVEL SUPPORT IS SLATED TO BE ACROSS THE FAR N AND W. DECIDED TO FOLLOW THE DAYCREW`S SETUP AND CONTINUE W/A CHANCE FOR SHOWERS(30-40%) INTO SUNDAY NIGHT. THE AXIS OF SHOWER ACTIVITY DOES SHIFT TO THE N AND E AND THIS IS SUPPORTED BY THE ECMWF/GFS AND SREF. FURTHER S ACROSS THE CENTRAL HIGHLANDS AND INTO THE DOWNEAST, PRETTY MUCH RAIN-FREE SUNDAY INTO SUNDAY NIGHT W/THE POTENTIAL FOR PARTIAL CLEARING. DAYTIME HIGH TEMPERATURES ON SUNDAY WILL BE DEPENDENT ON SUNSHINE AND THEREFORE, DECIDED TO GO W/MID TO UPPER 60S ACROSS THE CENTRAL AND DOWENAST AREAS AND SLIGHTLY COOLER ACROSS THE NORTHERN 1/2 OF THE CWA W/UPPER 50S TO AROUND 60. THE BIGGER CHALLENGE WILL BE MONDAY AS THE MEDIUM RANGE GUIDANCE IS SHOWING DISCONTINUITY W/THE BLOCKING PATTERN. THE ECMWF CONTINUES TO HOLD ITS COURSE OF BRINGING ANOTHER DISTURBANCE THROUGH THE REGION WHILE THE GFS WANT TO DRY IT OUT W/HIGH PRES NOSING DOWN FROM CANADA. THE GFS ENSEMBLE KEEPS THE FRONT LINGERING ACROSS NORTHERN AND SECTIONS. STAYED CLOSER TO AN ENSEMBLE APPROACH BLENDING IN THE ECMWF AND KEPT A CHANCE FOR SHOWERS IN THE AFOREMENTIONED AREAS FOR MONDAY INTO MONDAY EVENING. TEMPERATURES ON MONDAY ARE EXPECTED TO MID TO UPPER 50S ACROSS THE NORTH AND WEST AND LOW TO MID 60S CENTRAL AND DOWNEAST. QPF FOR THIS TERM IS FORECAST TO BE LESS THAN 0.15". && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE UNSETTLED PATTERN CONTINUES THROUGH THIS TERM. DRY WEATHER LOOKS TO RETURN FOR TUESDAY INTO MIDDAY WEDNESDAY AS HIGH PRES BUILDS DOWN FROM CANADA. COOLER FOR TUESDAY W/AOB NORMAL TEMPERATURES AND THEN TEMPERATURES ARE EXPECTED TO RISE INTO LOWER 60S BY WEDNESDAY. HIGH PRES IS FORECAST TO SLIDE OFF THE E BY THURSDAY W/A CHANCE FOR SHOWERS AS A FRONTAL BOUNDARY SLOWLY APPROACHES FROM THE WEST. DECIDED TO CONTINUE THE DAYCREW`S TREND AND CARRY THE CHANCE FOR SHOWERS INTO FRIDAY. THE UPSIDE TO THIS IS THAT TEMPERATURES ARE FORECAST TO BE IN THE 60S BOTH THURSDAY AND FRIDAY. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: IFR CONDITIONS ALL SITES EARLY THIS MORNING WITH SCT SHOWERS AND ISOLATED TSTMS. SKYCON WILL BREAK LATE MORNING BECMG MVFR INTO MID AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. SCT SHOWERS AND TSTMS WILL RETURN MID TO LATE AFTERNOON THROUGH EARLY EVENING WITH THE PASSING OF THE COLD FRONT. IMPROVING CONDITIONS OVERNIGHT AS HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT. SHORT TERM: MVFR POSSIBLE FOR THE NORTHERN TERMINALS ON SUNDAY MAINLY N OF KHUL. MVFR CONDITIONS AGAIN ON MONDAY ALL THE WAY TO KHUL AND VFR FOR KBGR AND KBHB. MVFR CIGS COULD POSE A PROBLEM FOR KBGR AND KBHB MONDAY NIGHT AND TUESDAY AS A ENE FLOW SETS UP. && .MARINE... NEAR TERM: AN SCA IS IN EFFECT FOR THE OUTER WATERS FOR WINDS AND SEAS. WINDS AND SEAS WILL FALL BELOW SCA CRITERIA LATE IN THE PERIOD. SHORT TERM: NO HEADLINES EXPECTED FOR THIS TERM. WINDS 10-15 KTS W/GUST TO 20 KTS ON SUNDAY DROPPING OFF TO 10 KTS OR LESS SUNDAY NIGHT THROUGH MONDAY. WINDS ARE EXPECTED TO PICK UP TO 10-15 KTS W/GUSTS NEAR 20 KTS MONDAY NIGHT INTO TUESDAY AS HIGH PRES BUILDS DOWN FROM CANADA AND THE FLOW BECOME ENE. WAVE HEIGHTS WILL RANGE FROM 2-4 FT MAINLY AWAY FROM THE INTRA COASTAL AREAS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ050-051. && $$ NEAR TERM...NORTON SHORT TERM...HEWITT LONG TERM...HEWITT AVIATION...NORTON/HEWITT MARINE...NORTON/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
456 AM EDT SAT MAY 10 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION LATER TODAY INTO TONIGHT. AN UPPER LEVEL DISTURBANCE IS EXPECTED TO SLIDE ACROSS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AT THE START OF THE NEAR TERM PERIOD THE WARM FRONT MOVES INTO NRN MAINE. THE UPPER RIDGE SHIFT EAST OF THE AREA AS THE COLD FRONT MOVES ACROSS NH. PARTIAL CLEARING TOMORROW MORNING INTO THE EARLY AFTERNOON IN THE WARM SECTOR COULD ALLOW FOR SOME THUNDERSTORM ACTIVITY ACROSS INTERIOR DOWNEAST AND THE INTERIOR HIGH LANDS TOMORROW AFTERNOON IN ADVANCE OF THE APPROACHING COLD FRONT. THE COLD FRONT WILL MOVE THROUGH LATE AFTERNOON EARLY IN THE EVENING. HIGHER PRESSURE WILL BUILD IN BEHIND THE COLD FRONT AND WILL DOMINATE THROUGH THE END OF THE PERIOD. LOADED HRRR FOR SKY/POP GRIDS THROUGH 12Z USED A BLEND OF NAM/GEM/GFS/ECMWF FOR BALANCE OF PERIOD. LOADED NAM/GEM/GFS/ECMWF FOR HRLY TEMP/DP/WNDS. HPC GUIDANCE FOR QPF. ADDED 15 PERCENT TO WNDS FOR GUSTS OVER LAND...20 PERCENT OVER WATER. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UNSETTLED CONDITIONS IN MONDAY WITH A BLOCKING PATTERN IN PLACE. A SFC TROF IS FORECAST TO SWING ACROSS THE REGION ON SUNDAY. BEST UPPER LEVEL SUPPORT IS SLATED TO BE ACROSS THE FAR N AND W. DECIDED TO FOLLOW THE DAYCREW`S SETUP AND CONTINUE W/A CHANCE FOR SHOWERS(30-40%) INTO SUNDAY NIGHT. THE AXIS OF SHOWER ACTIVITY DOES SHIFT TO THE N AND E AND THIS IS SUPPORTED BY THE ECMWF/GFS AND SREF. FURTHER S ACROSS THE CENTRAL HIGHLANDS AND INTO THE DOWNEAST, PRETTY MUCH RAIN-FREE SUNDAY INTO SUNDAY NIGHT W/THE POTENTIAL FOR PARTIAL CLEARING. DAYTIME HIGH TEMPERATURES ON SUNDAY WILL BE DEPENDENT ON SUNSHINE AND THEREFORE, DECIDED TO GO W/MID TO UPPER 60S ACROSS THE CENTRAL AND DOWENAST AREAS AND SLIGHTLY COOLER ACROSS THE NORTHERN 1/2 OF THE CWA W/UPPER 50S TO AROUND 60. THE BIGGER CHALLENGE WILL BE MONDAY AS THE MEDIUM RANGE GUIDANCE IS SHOWING DISCONTINUITY W/THE BLOCKING PATTERN. THE ECMWF CONTINUES TO HOLD ITS COURSE OF BRINGING ANOTHER DISTURBANCE THROUGH THE REGION WHILE THE GFS WANT TO DRY IT OUT W/HIGH PRES NOSING DOWN FROM CANADA. THE GFS ENSEMBLE KEEPS THE FRONT LINGERING ACROSS NORTHERN AND SECTIONS. STAYED CLOSER TO AN ENSEMBLE APPROACH BLENDING IN THE ECMWF AND KEPT A CHANCE FOR SHOWERS IN THE AFOREMENTIONED AREAS FOR MONDAY INTO MONDAY EVENING. TEMPERATURES ON MONDAY ARE EXPECTED TO MID TO UPPER 50S ACROSS THE NORTH AND WEST AND LOW TO MID 60S CENTRAL AND DOWNEAST. QPF FOR THIS TERM IS FORECAST TO BE LESS THAN 0.15". && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE UNSETTLED PATTERN CONTINUES THROUGH THIS TERM. DRY WEATHER LOOKS TO RETURN FOR TUESDAY INTO MIDDAY WEDNESDAY AS HIGH PRES BUILDS DOWN FROM CANADA. COOLER FOR TUESDAY W/AOB NORMAL TEMPERATURES AND THEN TEMPERATURES ARE EXPECTED TO RISE INTO LOWER 60S BY WEDNESDAY. HIGH PRES IS FORECAST TO SLIDE OFF THE E BY THURSDAY W/A CHANCE FOR SHOWERS AS A FRONTAL BOUNDARY SLOWLY APPROACHES FROM THE WEST. DECIDED TO CONTINUE THE DAYCREW`S TREND AND CARRY THE CHANCE FOR SHOWERS INTO FRIDAY. THE UPSIDE TO THIS IS THAT TEMPERATURES ARE FORECAST TO BE IN THE 60S BOTH THURSDAY AND FRIDAY. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: IFR CONDITIONS ALL SITES EARLY THIS MORNING WITH SCT SHOWERS AND ISOLATED TSTMS. SKYCON WILL BREAK LATE MORNING BECMG MVFR INTO MID AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. SCT SHOWERS AND TSTMS WILL RETURN MID TO LATE AFTERNOON THROUGH EARLY EVENING WITH THE PASSING OF THE COLD FRONT. IMPROVING CONDITIONS OVERNIGHT AS HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT. SHORT TERM: MVFR POSSIBLE FOR THE NORTHERN TERMINALS ON SUNDAY MAINLY N OF KHUL. MVFR CONDITIONS AGAIN ON MONDAY ALL THE WAY TO KHUL AND VFR FOR KBGR AND KBHB. MVFR CIGS COULD POSE A PROBLEM FOR KBGR AND KBHB MONDAY NIGHT AND TUESDAY AS A ENE FLOW SETS UP. && .MARINE... NEAR TERM: AN SCA IS IN EFFECT FOR THE OUTER WATERS FOR WINDS AND SEAS. WINDS AND SEAS WILL FALL BELOW SCA CRITERIA LATE IN THE PERIOD. SHORT TERM: NO HEADLINES EXPECTED FOR THIS TERM. WINDS 10-15 KTS W/GUST TO 20 KTS ON SUNDAY DROPPING OFF TO 10 KTS OR LESS SUNDAY NIGHT THROUGH MONDAY. WINDS ARE EXPECTED TO PICK UP TO 10-15 KTS W/GUSTS NEAR 20 KTS MONDAY NIGHT INTO TUESDAY AS HIGH PRES BUILDS DOWN FROM CANADA AND THE FLOW BECOME ENE. WAVE HEIGHTS WILL RANGE FROM 2-4 FT MAINLY AWAY FROM THE INTRA COASTAL AREAS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 AM EDT SUNDAY FOR ANZ050-051. && $$ NEAR TERM...NORTON SHORT TERM...HEWITT LONG TERM...HEWITT AVIATION...NORTON/HEWITT MARINE...NORTON/HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
904 PM EDT SUN MAY 11 2014 .SYNOPSIS... ALTHOUGH WARM WEATHER WILL QUICKLY RETURN...THE CHANCE FOR RAIN INCREASES AS THE WEEK PROGRESSES. && .NEAR TERM /THROUGH MONDAY/... CLUSTER OF STORMS OVER CENTRAL OHIO CONTINUES TO SLOWLY MOVE EASTWARD THIS EVENING. MODERATE CAPE AND WEAK SHEAR HAS SUPPORTED A FEW STORMS TO SEVERE LEVELS OVER OHIO BUT EXPECT THIS TREND TO QUICKLY DIMINISH AS INSTABILITY WEAKENS. THE MESOANALYSIS CONTINUES TO SHOW THAT MUCH OF OUR REGION IS CAPPED AND EARLIER SATELLITE DATA SHOWED VERY LITTLE CU DEVELOPMENT OVER OUR REGION WHICH REINFORCES THIS. HAVE UPPED THE POPS OVER OHIO BUT DO NOT THINK THERE IS MUCH OF A SEVERE THREAT. THE HRRR HAS CONSISTENTLY SUGGESTED THAT ANOTHER CLUSTER OF THUNDERSTORMS JUST SOUTH OF LAKE MICHIGAN WILL DIVE SOUTHEASTWARD TOWARDS THE REGION BY MORNING. WHETHER THESE SHOWERS AND STORMS HOLD TOGETHER REMAINS IN QUESTION BUT FOR NOW OPTED TO KEEP AT LEAST CHANCE POPS FOR THE WESTERNMOST ZONES FOR MUCH OF THE NIGHT...EXPANDING EASTWARD BY MORNING. WILL CONTINUE TO MONITOR RADAR TRENDS AND ADJUST FORECAST AS NEEDED. PRECIP CHANCES WILL CONTINUE THROUGH THE DAY ON MONDAY...INCREASING DURING THE AFTERNOON AS INSTABILITY INCREASES WITH DAYTIME HEATING. MOISTURE ADVECTION WILL INCREASE IN THE RESULTING SOUTH/SOUTHWEST FLOW PUSHING PWAT VALUES BACK UP TO JUST BELOW 1.5" WHICH IS NEARLY TWO STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. THERE IS A LARGE DIFFERENCE IN MODEL FORECAST CAPE VALUES FOR MONDAY AFTERNOON RANGING FROM 500 TO 1500 J/KG...BUT IN ANY CASE WITH RELATIVELY WEAK SHEAR AND STORM MOTION AROUND 15KTS...THE POTENTIAL FOR SEVERE WEATHER LOOKS LOW ATTM. WARM ADVECTION SHOULD ALLOW FOR TEMPERATURES TO BE APPROXIMATELY 15 DEGREES ABOVE MONDAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... WITH THE WESTERN TOUGH SLOWLY TRANSITIONING EAST...NOT MUCH CHANGE IS IN STORE FOR TUESDAY WITH MAX TEMPERATURES NOSING UP FURTHER AND SHOWER/THUNDERSTORM CHANCES AGAIN MAINLY DURING THE AFTERNOON AND EARLY EVENING. BY WEDNESDAY THE LONGWAVE TROUGH WILL HAVE MOVED FAR ENOUGH EAST TO INCREASE DYNAMICS ACROSS THE FORECAST AREA AND WITH PLENTY OF MOISTURE AND INSTABILITY ALREADY IN PLACE IT LOOKS LIKELY THAT THERE WILL BE MORE WIDESPREAD THUNDERSTORM COVERAGE. INCREASED DIRECTIONAL AND SPEED SHEAR ALOFT ALSO RAISES THE POTENTIAL FOR MORE ORGANIZED CONVECTION BY WEDNESDAY...BUT ATTM VALUES ARE STILL MARGINAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... GIVEN THE AMPLITUDE OF THE FLOW PTN PROGGED FOR THIS WEEK...EXPECT THAT TIMING ADJUSTMENTS FOR THE EWD PROGRESS OF THE UPR TROF/CDFNT SHOULD BE ANTICIPATED. NEVERTHELESS...THE LONG TERM FORECAST FEATURES A CONTINUATION OF LIKELY POPS THROUGH THURSDAY FOLLOWED BY CHC NMBRS INTO THE WEEKEND TO ACCOUNT FOR THE ADVN OF THE TROF AND CURRENTLY PROGGED CUTOFF OVR THE GREAT LAKES REGION. PCPN AND FRONTAL PASSAGE WL SPPRT TEMPS NR...THEN BLO THE SEASONAL AVGS FOR THE PD. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... SCT MID CLOUDS AND A CANOPY OF CIRRUS DOMINATE THE FORECAST. SHOWERS AND THUNDERSTORMS OVER IL/IA AS OF 23Z COULD HOLD TOGETHER AND CROSS THE REGION DURING THE EARLY MORNING HOURS MONDAY ACCORDING TO THE HRRR. DO NOT FORESEE ANYWHERE NEAR THE INTENSITY THEY CURRENTLY HAVE...HOWEVER A BRIEF DROP TO MVFR VIS/CIGS IS POSSIBLE. GIVEN CONFIDENCE IS LOW...DID NOT INCLUDE ANY PCPN MENTION IN THE TERMINALS. SHOWERS AND THUNDERSTORMS OVER WRN OH HAVE A LOW PROBABILITY OF IMPACTING ZZV LATER TONIGHT...IF PCPN DOES OCCUR MVFR FOG IS POSSIBLE TOWARD DAWN MONDAY MORNING. .OUTLOOK.../00Z TUESDAY MONDAY THROUGH FRIDAY/... MVFR AND PERHAPS BRIEF IFR WEATHER IS POSSIBLE IN SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF A COLD FRONT THAT CROSSES MID WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
851 PM EDT SUN MAY 11 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE INTO THE SOUTHEAST STATES TONIGHT...LEADING TO WARM CONDITIONS THROUGH THE FIRST PART OF THE WEEK. A COLD FRONT WILL MOVE INTO THE REGION WEDNESDAY AND REMAIN OVER THE AREA THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... HIGH PRESSURE IS LOCATED ACROSS THE MID ATLANTIC AND SOUTHEASTERN COAST THIS EVENING. A DISTURBANCE MOVING IN ZONAL FLOW ALOFT HAS PRODUCED SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE MIDWEST AND CLOUD DEBRIS WILL ENTER THE POTOMAC HIGHLANDS AND CENTRAL FOOTHILLS TONIGHT. A SUBTROPICAL RIDGE ACROSS THE GULF COAST STATES WILL WILL PUSH NORTHWARD THROUGH THE START OF THE WORK WEEK. HIGH PRESSURE WILL MOVE OFF THE COAST TONIGHT AND RETURN FLOW WILL INCREASE DEWPTS OVERNIGHT AND MONDAY. MOISTURE FROM THE ACTIVITY IN THE MID WEST WILL MOVE EASTWARD CROSSING THE OHIO VALLEY AND NRN PORTIONS OF THE MID ATLANTIC BY SUNRISE. HI RES MODELS HAVE SHOWERS DISSAPATING AS THEY REACH THE POTOMAC HIGHLANDS LATE TONIGHT. THE MID ATLANTIC WILL BE LOCATED ON THE NORTHERN EDGE OF A NORTHWARD ADVANCING SUBTROPICAL RIDGE MONDAY. DAYTIME HEATING WILL RESULT IN A CU FIELD ACROSS THE REGION AND SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE HIGHER ELEVATIONS SUCH AS THE POTOMAC HIGHLANDS AND BLUE RIDGE BY MIDDAY. A LEE TROUGH IS ALSO EXPECTED TO FORM ALONG AND EAST OF THE BLUE RIDGE BY MONDAY AFTERNOON WHICH MAY PRODUCE A ZONE FOR CONVECTIVE DEVELOPMENT. WESTERLY FLOW ALOFT WILL LEAD TO THE POTENTIAL OF THIS ACTIVITY TO MOVE EASTWARD AND REACH THE I-95 CORRIDOR BY MONDAY AFTERNOON. NAM FCST SOUNDINGS SHOW A SLIGHT CAP BUT GFS AND RAP SHOW LITTLE INHIBITION ACROSS THE REGION TOMORROW. SFC DEWPTS AND CLOUD COVER WILL BE FACTORS IN THE COVERAGE OF SHOWERS AND THUNDERSTORMS EAST OF THE BLUE RIDGE BUT AT THIS TIME DEWPTS ARE FCST TO REACH THE LOW TO MID 60S EAST OF THE BLUE RIDGE. THIN CLOUD DEBRIS IS EXPECTED ACROSS THE REGION BY MONDAY MORNING DUE TO THE ACTIVITY IN THE MIDWEST. THE AIRMASS OVER THE MIDWEST TONIGHT WILL BE MOVING OVER THE MID ATLANTIC MONDAY SETTING THE STAGE FOR THE POTENTIAL FOR SHOWERS AND POSSIBLY THUNDERSTORMS. THE SVR THREAT IS LOW DUE TO WEAK FORCING AND MARGINAL INSTABILITY AND SHEAR. TEMPS WILL RISE INTO THE MID TO UPPER 80S MONDAY AFTERNOON AND A RIVER/BAY BREEZE MAY ALSO PRODUCE LOW LEVEL CONVERGENCE TO FORM SHOWERS AND POSSIBLY THUNDERSTORMS. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... IN TERMS OF CONVECTIVE INSTABILITY OVER A MULTI-DAY PERIOD...THE NEXT FEW DAYS WILL BE THE MOST UNSTABLE FOR OUR REGION SO FAR THIS YEAR. THE PASSAGE OF ANY ORGANIZED SYNOPTIC-SCALE FEATURE WILL BE A SLOW BOIL HOWEVER...W/ EACH DAY FOR THE UPCOMING WORK WEEK HAVING THE POTENTIAL FOR SOME WEAK CONVERGENCE/DIURNAL CONVECTION. AN OFFSHORE HIGH WILL SUPPLY THE MUCH-ABOVE AVG TEMPS AND MOISTURE. A DEEPENING UPPER TROUGH TO OUR WEST WILL SUPPLY THE GRADUALLY ENVIRONMENT FOR STEEPER LAPSE RATES. DESPITE THESE MORE FAVORABLE CONVECTIVE CONDITIONS...ONLY LOCAL-SCALE AND/OR WEAK CONVERGENCE ZONES WILL HELP DEVELOP OUR SHOWER/TSTM CHANCES FOR THE NEXT FEW DAYS. AFTER SOME SCATTERED/ISOLATED TSTMS ON MON-MON EVE...CONDITIONS WILL SETTLE DOWN AGAIN W/ A WARM OVERNIGHT THAT WILL SET US UP FOR ANOTHER HOT DAY ON TUE. WHILE MIDWEST AND MS VLY ARE UNDER THE CONVECTIVE CROSSHAIRS MON-TUE...A NEARBY WARM FRONT AND SOME WEAK LEE TROUGH ACTIVITY WILL HELP DEVELOP TSTMS OVER THE MID ATLC ON TUE AFTN. GIVEN SOME CONVECTION INITIATION...THERE WILL BE AMPLE INSTABILITY FOR INDIVIDUAL CELLS TO PRODUCE STRONG-SEVERE WX IN ISOLATED AREAS. WE`LL BE EXPERIENCING SOME OF THE HIGHEST DEWPOINTS OF THE YEAR SO FAR ON TUE AFTN. COUPLE THAT W/ TEMPS ON DOORSTEP OF THE 90F MARK AND WE`LL SEE SOME OF THE WARMEST HEAT INDICES OF THE YEAR...POTENTIALLY IN THE M90S. THE FRONTAL SYSTEM CAUSING LIKELY WIDESPREAD CONVECTION A COUPLE OF STATES TO OUR WEST ON TUE WILL BREAK OFF FROM ANOTHER UPPER WAVE OVER THE SRN PLAINS AND TAKE OFF TO THE NE - WELL AWAY FROM OUR AREA. THE COLD FRONT WON`T EVEN PASS OVER OUR AREA AS THE SRN PLAINS UPPER WAVE GEARS-UP TO DEVELOP IT`S OWN LOW PRESSURE SYSTEM. A SFC HIGH WILL DEVELOP OFF THE NEW ENGLAND COASTLINE LATE TUE INTO WED...SETTING-UP AN ONSHORE ELY FLOW OVER THE MID ATLC - ADDING SOME STABILITY AND COOLER CONDITIONS FOR AREAS E OF THE BLUE RIDGE ON WED. TEMPS WILL TAKE A BREAK FROM THE U80S ON WED...LIKELY STRUGGLING TO REACH THE L80S - OUTSIDE OF THE LOWER SHEN VLY/VA PIEDMONT. TSTMS WILL STILL BE POSSIBLE ACROSS THE AREA LATER IN THE DAY AS THE ONSHORE FLOW SUBSIDES AND SOME HEATING PUSHES THRU THE MARINE LAYER. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... STILL LOOKING GOOD FOR POTENTIAL HEAVY RAIN THURSDAY DESPITE SOME TIMING DIFFERENCES IN GFS/ECMWF WITH FROPA. LONG SOUTHERLY FETCH AHEAD OF DEEP LONG WAVE TROUGH DRAWS IN AMPLE MOISTURE FROM GULF/CARIBBEAN THROUGH MID WEEK. MOISTURE AXIS IMPINGING LOW LEVEL THERMAL BOUNDARY WILL PROVIDE FOCUSED LOW LEVEL LIFT AND SOUTHERLY SHORT WAVE LIFTING NORTH ON THE FRONT SIDE OF THE UPPER TROUGH WILL PROVIDE SYNOPTIC LIFT FOR NUMEROUS SHOWERS/STORMS THURSDAY. FORECAST SOUNDINGS SHOW THIN CAPE PROFILES AND DEEP WARM CLOUD LAYER...FAVORABLE FOR COLLISION-COALESCENCE HEAVY RAIN PROCESSES. THE FRONT IS SOMEWHAT PROGRESSIVE HOWEVER WHICH LOOKS TO HINDER TRAINING ECHOES AS DRY AIR PUSHES IN POST COLD FRONT LATE THURSDAY NIGHT INTO FRIDAY. COOLER AIRMASS BUILDS IN AS UPPER TROUGH MOVES ACROSS THE GREAT LAKE FRIDAY INTO THE WEEKEND. THIS COOLER POOL ALOFT COMBINED WITH DAYTIME SURFACE HEATING MAY PRODUCE SOME INSTABILITY CONVECTION AND HAVE MAINTAINED POPS FOR THIS SHOWER POTENTIAL. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL CONTINUE ACROSS THE AREA TONIGHT BEFORE MOVING OFF THE EAST COAST BY MONDAY. NO VIS/CIG FLIGHT RESTRICTIONS EXPECTED DURING THE VALID TAF PERIOD. SHOWERS AND THUNDERSTORMS MAY FORM AT HIGHER ELEVATIONS BY MONDAY AFTERNOON AND A FEW MAY MOVE INTO THE TAF SITES BY SUNSET. SOUTHERLY WINDS EXPECTED THROUGH TUESDAY. WHILE A LARGE-SCALE LOW PRESSURE TROUGH BUILDS WELL TO OUR WEST EARLY THIS WEEK...THE EASTERN SEABOARD WILL WARM-UP AND THE ENVIRONMENT WILL BECOME MORE UNSTABLE. DAYTIME HEATING WILL PROVIDE THE SET-UP FOR CONVECTIVE POTENTIAL BUT THE TRIGGER FOR DEVELOPING SHOWERS AND TSTMS WILL BE LIMITED. A CHANCE OF PRECIP POSSIBLE THROUGHOUT MUCH OF THE WEEK...THOUGH THE FIRST HALF WILL BE THE WARMEST PERIOD. A SLOW MOVING COLD FRONT IS EXPECTED TO BRING UNSETTLED WEATHER WITH CHANCES OF STORMS/HEAVY RAIN FOR MAINLY THURSDAY AND THURSDAY NIGHT. && .MARINE... HIGH PRESSURE SHIFTS SOUTH OF THE WATERS TONIGHT. WEAK NW WIND WILL BECOME TO THE S BY EVENING. S WINDS LIKELY INCREASE TONIGHT INTO MONDAY...POSSIBLY TO AROUND 15 KT UP THE BAY. BUT WITH RELATIVELY WEAK GRADIENT...SCA CONDITIONS ARE NOT EXPECTED AT THIS TIME. A FEW SCT SHOWERS ARE POSSIBLE ACROSS THE WATERS LATE MONDAY AFTERNOON INTO EARLY EVENING. HIGH PRESSURE WILL BE IN PLACE FOR THE FIRST HALF OF THE WEEK... KEEPING THE WATERS RELATIVELY QUIET. SOME SLY CHANNELING LATE MON INTO TUE...W/ THE MAIN THREATS BEING POTENTIAL TSTMS EACH AFTN/EVE THRU MID WEEK. UNSETTLED WEATHER CONDITIONS WITH CHANCES OF STORMS/HEAVY RAIN ARE EXPECTED MAINLY THURSDAY AND THURSDAY NIGHT DUE TO A SLOW MOVING COLD FRONT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BPP NEAR TERM...BPP/HAS SHORT TERM...GMS LONG TERM...AEB AVIATION...HAS/GMS/AEB MARINE...HAS/GMS/AEB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
751 PM EDT SUN MAY 11 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 347 PM EDT SUN MAY 11 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE ENERGY ROUNDING BASE OF AMPLIFIED TROF OVER THE FOUR CORNERS REGION OF THE SW CONUS. MODELS SHOW THIS STRONG SHORTWAVE BEGINNING TO EJECT NE FROM WRN/CENTRAL PLAINS TONIGHT AS ITS ASSOC SFC LOW LIFTS NE THROUGH THE PLAINS. INCREASING MOISTURE AND ISENTROPIC ASCENT AHEAD OF THIS LOW PRES SYSTEM SHOULD SIGNAL THE BEGINNING OF A FAIRLY WET PERIOD FOR THE CWA STARTING LATE TONIGHT AND CONTINUING INTO EARLY TUESDAY. TONIGHT...AS THE STRONGER SHORTWAVE BEGINS TO EJECT OUT OF THE DEEPENING UPPER TROF THE SFC LOW PRES WILL IN TURN LIFT NE THRU THE PLAINS. THE EVENING SHOULD REMAIN DRY...AND PERHAPS CONTINUE INTO THE OVERNIGHT OVER THE NE HALF OF THE FCST AREA CLOSER TO DRY LOW-LEVEL NE TRAJECTORIES OUT OF SFC HIGH PRES IN ONTARIO. MOST OF THE MODELS SHOW INCREASING 850-700 MB MOISTURE TRANSPORT AND ADVECTION INTO THE AREA FM THE SOUTH BTWN 06-12Z ALONG WITH INCREASING 300-305K WAA/ISENTROPIC ASCENT AHEAD OF THE APPROACHING LOW PRES SYSTEM. MODELS ALSO INDICATE A SUBTLE SHORTWAVE WILL LIFT NE INTO THE UPPER MISSISSIPPI VALLEY LATE TONIGHT THAT WILL FURTHER AID THE DEVELOPMENT/SPREAD OF SHRA NE INTO UPPER MI DURING THE OVERNIGHT. NOT MUCH INSTABILITY IS NOTED PER 0-3KM MUCAPE OFF THE NAM/GFS. WITH A COUPLE HUNDRED J/KG AND SHOWALTER INDEX FALLING JUST BLO 0C OVER THE FAR SCNTRL LATE TONIGHT IN MOST MODEL GUIDANCE...WILL CONTINUE THE MENTION OF THUNDER IN THAT AREA LATE TONIGHT. MONDAY...WITH H85 WARM FRONT IN THE VICINITY...MODELS SHOW CONTINUED MOISTURE TRANSPORT/ADVECTION AT H85-H7 ACROSS THE FRONTAL BOUNDARY AS PWATS OVER OUR AREA RISE TO AROUND 1.5 INCHES OR WELL OVER 200 PCT OF NORMAL. SHORTWAVE/PV ANAMOLY EMERGING NORTHEAST OUT OF THE WESTERN CONUS TROUGH WILL SPREAD AREA OF H85-H5 Q-VECTOR CONVERGENCE INTO THE UPPER GREAT LAKES BY MONDAY AFTERNOON. DESPITE THESE FAVORABLE FACTORS FOR SHOWERS...MODELS STILL DIFFER SOMEWHAT ON PLACEMENT OF MAXIMUM MOISTURE ADVECTION...WITH THE GFS AND NAM INDICATING BEST MOISTURE ADVECTION WEST AND THE REG GEM TO THE EAST. HOWEVER CORFIDI VECTORS...BOTH FORWARD AND BACKWARD PROPAGATING...ARE GENERALLY ORIENTED FROM WEST TO EAST ACROSS THE FCST AREA WHICH WOULD ARGUE SHOWERS MAKING IT INTO THE WRN FCST AREA SHOULD ADVECT INTO THE ERN COUNTIES AS WELL. GOING FCST LIKELY POPS STILL SEEM REASONABLE CONSIDERING THE H85 FRONT IS IN THE VICINTY. WILL CONTINUE IDEA OF LIKELY POPS WEST IN THE MORNING SPREADING EAST INTO THE AFTERNOON HRS. ALSO WILL CONTINUE TO KEEP MENTION OF TSRA MAINLY OVER SOUTH HALF INTO THE WESTERN CWA ALONG NORTHERN GRADIENT OF ELEVATED INSTABILITY WITH SEVERAL HUNDRED J/KG OF ELEVATED CAPE AND NEG SHOWALTER INDICES. BIGGEST THREAT WITH ANY TSRA WILL BE HEAVY RAIN GIVEN HIGH PWATS ACROSS AREA. ANY HEAVY RAIN OVER THE WRN COUNTIES WILL CONTINUE TO ADD MORE RUNOFF TO RIVERS ALREADY RUNNING NEAR BANKFULL...ESPECIALLY THE STURGEON...TRAP ROCK AND MICHIGAMME RIVERS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 329 PM EDT SUN MAY 11 2014 AT THE START OF THE PERIOD /00Z TUE/ MODELS ARE IN DECENT LARGE SCALE AGREEMENT IN SHOWING A SHARP AND DEEP 500MB TROUGH FROM THE SASK/MANITOBA BORDER S ACROSS THE DAKOTAS THEN TO THE FOUR CORNERS REGION. A 1004MB SFC LOW WILL BE SOMEWHERE IN THE SERN MN TO NWRN WI. MODELS HAVE BEEN TRENDING TOWARD THE CURRENT SOLUTION THAT TAKES THE SFC LOW W OF THE CWA TO JUST N OF THE MN ARROWHEAD BY 12Z TUE. WITH THE MORE NLY TRACK...MODELS ARE NOW SHOWING THE SFC WARM FRONT MOVING INTO THE FAR SRN CWA MON NIGHT...BUT WITH COLD LAKE TEMPS AND CONVECTION EXPECTED ALONG THE FRONT...CONFIDENCE IN THE FRONT MOVING THAT FAR N IS LOW. FORCING FROM UPPER LEVEL HEIGHT FALLS FROM THE DEEPENING TROUGH...GOOD MOISTURE TRANSPORT AND ISENTROPIC ASCENT WILL FAVOR PERIODS OF MODERATE RAIN SHOWERS MON NIGHT INTO EARLY TUE. THE OCCLUDED/COLD FRONT WILL MOVE THROUGH FROM LATE MON NIGHT INTO TUE...BRINGING AN END TO THE BULK OF THE PRECIP. SOME SHOWERS COULD REDEVELOP BEHIND THE FRONT AS CLEARING OVER THE WRN U.P. MAY ALLOW FOR ENOUGH INSTABILITY. MODELS GENERALLY SHOW ADDITIONAL QPF AMOUNTS OF AN INCH...BUT THAT WILL BE HIGHLY DEPENDENT ON EXACT DETAILS OF CONVECTION...MAKING EXACT PRECIP AMOUNTS HIGHLY UNCERTAIN. INSTABILITY FOR CONVECTION WILL ALSO BE HIGHLY UNCERTAIN DUE TO DEPENDENCY ON WARM FRONTAL LOCATION AND OTHER CONVECTION. IF THE FRONT CAN MAKE IT FARTHER N...THE WARM NOSE AT 900MB MAY BE STRONG ENOUGH TO LEAD TO GREATER ELEVATED CONVECTION. GFS AND NAM ARE SHOWING UP TO AROUND 1000 J/KG OF ELEVATED CAPE OVER THE SCENTRAL CWA...BUT STILL THINK THAT IS NOT AS LIKELY AS THE FRONT WILL PROBABLY STAY FARTHER S. IF THE WORST CASE SCENARIO OF THE FARTHER N FRONTAL POSITION DOES OCCUR...SOME HAIL WOULD BE POSSIBLE SCENTRAL. THE ADDITIONAL QPF AMOUNTS /COMBINED WITH PRECIP ON MON/ WOULD LIKELY LEAD TO ADDITIONAL FLOODING CONCERNS ON AREA RIVERS THAT ALREADY HAVE ELEVATED LEVELS. THE UPPER TROUGH MOVES OVERHEAD THROUGH MUCH OF THE REST OF THE WORK WEEK...ALTHOUGH THE ECMWF CLOSES IT OFF INTO A LOW THU INTO FRI. THE ECMWF SOLUTION WOULD RESULT IN MORE WIDESPREAD PRECIP THU INTO FRI...BUT THE GFS AND GEM SOLUTIONS WITH THE OPEN TROUGH WOULD LEAD TO SCATTERED SHOWER ACTIVITY MAINLY DURING PEAK HEATING WED THROUGH FRI. THIS DUE TO 850MB TEMPS OF -2C TO -4C WED THROUGH FRI NIGHT /AND AS COLD AS -7C IF THE ECMWF SOLUTION PANS OUT/. OF COURSE...THIS WILL LEAD TO A RETURN OF SIGNIFICANTLY BELOW NORMAL TEMPS /10-15 DEGREES BELOW NORMAL/. NEXT WEEKEND LOOKS DRIER AND WARMER AS RIDGING MOVES OVERHEAD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 751 PM EDT SUN MAY 11 2014 LINGERING DRY AIR AT THE LOW LEVELS WILL ENSURE VFR CONDITIONS THROUGH THIS EVENING. LATE TONIGHT...NORTHWARD ADVANCING LOW PRESSURE AND A WARM FRONT WILL SPREAD SHRA INTO UPPER MI. THERE IS STILL SOME UNCERTAINTY IN HOW FAST PCPN WILL DEVELOP. KIWD HAS THE BEST CHC OF CONDITIONS FALLING TO MVFR AROUND 08Z WITH THE ONSET OF RAIN. EXPECT ALL SITES TO QUICKLY FALL TO IFR OR LIFR IN LOWERING STRATUS BY 12Z OR SHORTLY THEREAFTER WITH CONTINUED SHOWERS AND ADVECTION OF HIGHER DEWPOINTS INTO THE AREA. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 347 PM EDT SUN MAY 11 2014 NE WINDS 15-25 KTS THIS EVENING WILL BEGIN TO INCREASE OVER WESTERN PORTIONS OF LK SUPERIOR LATE TONIGHT AND MORE SO ON MONDAY AS LOW PRESSURE APPROACHES FROM THE SOUTHWEST. DECIDED TO REPLACE GALE WATCH WITH GALE WARNING OVER WESTERN TWO ZONES LATE TONIGHT THROUGH TUE EVENING. WINDS OVER THE REST OF THE LAKE WILL STAY AT OR BLO 30 KTS. WINDS DIMINISH LATER MONDAY NIGHT AND THEN SWITCH TO THE WEST TO 20-25 KTS ON TUESDAY. LOW SLOWLY SLIDES TO THE NORTHEAST OF LK SUPERIOR REST OF THE WEEK...RESULTING IN NORTHWEST WINDS MAINLY STAYING BLO 20 KTS. && .HYDROLOGY... ISSUED AT 329 PM EDT SUN MAY 11 2014 HIGHS MOSTLY IN THE 60S TODAY WILL RESULT IN ADDITIONAL SNOWMELT OVER HIGHER TERRAIN OF NORTHERN UPR MICHIGAN. MINIMAL RAIN AMOUNTS ARE EXPECTED THROUGH AT LEAST EARLY TONIGHT...BUT RAIN CHANCES INCREASE LATE TONIGHT INTO TUESDAY MORNING. THERE IS A POTENTIAL FOR MODERATE TO HEAVY RAIN OVER THE AREAS THAT ARE STILL MELTING SNOW...SO THE RECENT HIGHER RIVER LEVELS WILL CONTINUE THROUGH MUCH OF THE UPCOMING WEEK. THE FLOOD WARNING CONTINUES FOR THE STURGEON RIVER NEAR CHASSELL...WHILE ADVISORIES ARE IN PLACE FOR OTHER PORTIONS OF THE STURGEON RIVER IN HOUGHTON AND BARAGA COUNTIES AS WELL AS PORTIONS OF THE MICHIGAMME RIVER. IF HEAVIER RAINS MATERIALIZE EARLY THIS WEEK... ADDITIONAL ADVISORIES AND WARNINGS MAY BE NEEDED. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 6 AM EDT /5 AM CDT/ MONDAY TO MIDNIGHT EDT /11 PM CDT/ MONDAY NIGHT FOR LSZ162. GALE WARNING FROM 10 AM TO 11 PM EDT MONDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...TITUS AVIATION...JLB MARINE...VOSS HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1202 AM EDT SAT MAY 10 2014 .AVIATION... //DISCUSSION... THE COLD FRONT WILL BE THROUGH ALL TERMINAL LOCATIONS TO START THE FORECAST LEAVING A CLEARING TREND BEHIND THROUGH THE EARLY MORNING. THE EXCEPTION WILL BE IN THE MBS AREA WHERE A FIELD OF VFR STRATUS WILL SPREAD IN FROM WESTERN LOWER MICHIGAN. TRENDS IN SATELLITE IMAGERY SUGGEST IT WILL NOT BE ABLE TO REACH SOUTH OF FNT BEFORE MOVING INTO ONTARIO TOWARD SUNRISE. THE CLOUDS WILL BE DRIVEN OUT OF THE AREA BY HIGH PRESSURE BUILDING IN DURING THE MORNING. THE HIGH PRESSURE WILL BRING IN AND MAINTAIN VFR CONDITIONS THROUGH SATURDAY EVENING. //DTW THRESHOLD THREATS... * NONE. && .PREV DISCUSSION...ISSUED 945 PM EDT FRI MAY 9 2014 UPDATE... SURFACE ANALYSIS AND OBSERVATIONS INDICATE THE COLD FRONT SURGING THROUGH THE TRI CITIES AND ABOUT TO PASS THROUGH FLINT AT PRESS TIME. THE FRONT WILL SUPPORT A FEW MORE POCKETS OF SHOWERS AND THUNDERSTORMS BUT THE STRENGTH OF ANY STORMS WILL BE LIMITED BY INSTABILITY WANING AFTER SUNSET. EARLIER UPDATES SHIFTED THE FOCUS ON PRECIPITATION FROM THE PREFRONTAL LINE EXITING INTO ONTARIO TO THE ACTUAL COLD FRONT FOR THE REST OF THE EVENING. EXPECT THE FRONT TO BE THROUGH THE ENTIRE AREA SHORTLY AFTER MIDNIGHT AND LEAVE SE MICHIGAN WITH DRY CONDITIONS AND A CLEARING TREND THROUGH THE EARLY OVERNIGHT. THIS WILL BE FOLLOWED BY STRATUS MOVING IN FROM WISCONSIN AND WESTERN LOWER MICHIGAN LATER IN THE NIGHT THAT SHOULD MOVE OVER MOST OF THE REGION NORTH OF INTERSTATE 69. THESE CLOUD EXPECTATIONS WILL BE REFINED WITH ONE MORE UPDATE TO COVER TRENDS THROUGH SATURDAY MORNING. PREV DISCUSSION...ISSUED 400 PM EDT FRI MAY 9 2014 SHORT TERM...THIS EVENING AND TONIGHT CLOUDS AND SHALLOW EARLY AFTERNOON CONVECTION HAVE RESULTED IN A RATHER NEBULOUS PICTURE FOR THUNDERSTORM POTENTIAL THIS EVENING. ABUNDANT MID AND HIGH CLOUDS HAVE LIMITED BOUNDARY LAYER RECOVERY IN THE WAKE OF THE PASSING CONVECTION, ALTHOUGH MID 70S TEMPS AND DEWPOINTS AROUND 60 ARE MAKING A RENEWED PUSH INTO SOUTHWEST LOWER MICHIGAN DURING THE MID AFTN AND CLOUD OPACITY IS DECREASING. MESOANALYSIS SHOWS MUCAPES AT A RATHER MODEST 500 J/KG OVER WESTERN LOWER FOR NOW...BUT THE 12Z NAM AND RECENT RUNS OF THE RUC SUGGEST A RECOVERY TO 1000 J/KG CAPE BY AROUND 22Z IN ADVANCE OF THE APPROACHING COLD FRONT. THE OVERZEALOUS HANDLING OF QPF BY TODAY`S NWP MAKES THE PROGGED RECOVERY ALL THE MORE IMPRESSIVE. HOWEVER, IN AND AN ATTEMPT TO ADDRESS UNCERTAINTIES REGARDING BOTH THE MID-LEVEL AND LOW-LEVEL THERMODYNAMIC ENVIRONMENT RESULTING FROM BOTH POOR MODEL PERFORMANCE AND EARLY CONVECTION, A SPECIAL SOUNDING WAS LAUNCHED AT APPROXIMATELY 1930Z. THE DATA WILL BECOME AVAILABLE SHORTLY AFTER ISSUANCE OF THE AFTERNOON PACKAGE. FINALLY, ALTHOUGH ANY CONVECTION THAT BUBBLES UP IN ADVANCE OF THE FRONT MAY BEGIN TO LOOSE FOOTING IN THE BOUNDARY LAYER AROUND 00Z...STEEPENING MID-LEVEL LAPSE RATES WILL MAINTAIN RESPECTABLE MID-LEVEL INSTABILITY WELL INTO THE EVENING HOURS AND MAY EVEN ALLOW A HAIL THREAT TO DEVELOP IN ADDITION TO WIND AS UPDRAFTS ARE ALLOWED TO DEEPEN. WIDESPREAD SEVERE WEATHER IS NOT EXPECTED...PARTICULARLY GIVEN PARALLEL NATURE OF THE MEAN FLOW TO THE INITIATING BOUNDARY...BUT AT LEAST A MARGINAL THREAT WILL EXIST DEPENDING ON THE BEHAVIOR OF INDIVIDUAL CELLS. WILL MAINTAIN CHANCE POPS THROUGH THE EVENING HOURS AND MENTION A RISK OF AT LEAST ISOLATED WIND/HAIL THREATS DEVELOPING OVER THE NEXT SEVERAL HOURS IN THE HWO. THE GREATEST THREAT WILL BE FOCUSED FURTHER SOUTH AND WEST WHERE INSTABILITY WILL BE MAXIMIZED. LONG TERM... DIFFERENTIAL HEIGHT RISES BEHIND THE DEPARTING SHARP MIDLEVEL TROUGH AXIS WILL LEAD TO A SURFACE RIDGE ACROSS SOUTHEASTERN MICHIGAN ON SATURDAY. DRYING SIGNAL IN THE 925-850MB LAYER SUPPORTS THE FORECAST SOUNDINGS OF LCL HEIGHTS EVENTUALLY REACHING A VERY HIGH 6000 FT AGL. THE ENVIRONMENT FAVORABLE FOR DEEP TURBULENT MIXING WILL EVENTUALLY ALLOW BREEZY WESTERLIES TO DEVELOP DURING THE LATE AFTERNOON. SURFACE WIND GUSTS ARE EXPECTED TO REACH 25 TO 30 KNOTS. FORECASTED SOUNDINGS FOR SATURDAY ARE NOW QUITE A BIT DIFFERENT WITH ANY EXPECTED MIDLEVEL LAPSE RATES. IN FACT...POCKET OF STEEP MIDLEVEL LAPSE RATES IS NOWHERE TO BE SEEN...SUGGESTING THAT EVEN A SCATTERED CU FIELD WILL BE DIFFICULT. HIGHS SATURDAY WILL BE COOLER...READING REACHING THE UPPER 60S FOR MANY AREAS...72 OR 73 DEGREES FOR THE HIGHER SURFACE PRESSURE/LOWER TERRAIN LOCATIONS ACROSS THE EXTREME SOUTHEAST. THE INBOUND LONGWAVE RIDGE WILL BE VERY PROGRESSIVE DURING THE LATTER HALF OF THE WEEKEND...AMPLIFYING AS WELL. PRECEDING MID TO UPPER LEVEL TROPOSPHERIC DEFORMATION IS PROGGED TO BE VERY GOOD WHICH WILL AID IN THE RAPID DEVELOPMENT OF A WARM FRONT BY SUNDAY. EARLY PART OF THE DAY IS EXPECTED TO BE QUIET WITH VERY DRY AIR IN RESIDENCE DURING THE MORNING. WIND TRAJECTORIES WILL EVENTUALLY VEER SOUTHWESTERLY WHICH WILL ALLOW WARMTH AND INSTABILITY TO INCREASE FOR THE AFTERNOON. THE SUNDAY PERIOD HAS BEEN A NOISY ONE WITHIN THE MODELS SO CONFIDENCE IS NOT OVERLY HIGH...ESPECIALLY WITH REGARDS TO TIMING. HOWEVER...ENOUGH UPPER LEVEL FORCING APPEARS TO BE COMING TOGETHER SUPPORTIVE OF A MID CHANCE POP IN THUNDERSTORMS FOR THE SOUTHERN HALF OF THE CWA. THE LATE AFTERNOON PUSH WITH WARMTH WILL ALLOW TEMPERATURES TO REACH THE MID 70S FOR MANY LOCATIONS. MONDAY WILL BEGIN A PERIOD OF ACTIVE WEATHER FOR THE EXTENDED AS A WARM FRONT LIFTS NORTH INTO THE TRI CITIES AREA. AGAIN...WARM AND MOIST AIR WILL ADVECT NORTH VIA A 40KT H85 JET. THIS WILL BRING PWAT VALUES OVER 1.5 INCHES. WILL CONTINUE TO TREND UPWARD WITH POPS 50 TO 60 PERCENT. THE COLD FRONT WILL SWING THROUGH ON TUESDAY AND CONTINUE THE HIGH POP EVENT. BOTH DAYS POSE THE THREAT FOR THUNDER AS LI/S WILL BE NEGATIVE. MUCH LIKE THE PAST 2 DAYS HERE...MONDAY IN THE WARM SECTOR WILL REMAIN CAPPED BUT WITH CAPE WELL OVER 2500 J/KG. TUESDAY WILL HAVE MORE POTENTIAL WITH THE STRONGER FORCING...BUT LOWER CAPE VALUES. CHANCE POPS WILL ALSO BE IN THE FORECAST WEDNESDAY AS REMNANT MOISTURE FROM THE SLOW CHURNING LOW PRESSURE REMAINS PROXIMAL TO THE AREA. THIS WILL BE ALONG WITH A GENERAL THUNDER THREAT. THE REST OF THE PERIOD STILL LOOKS TO REMAIN COOL WITH TEMPS BELOW CLIMO. MARINE... A STRONGLY STABLE PROFILE OVER THE GREAT LAKES WILL KEEP WIND GUSTS MAINLY UNDER 30 KNOTS. THE COLD FRONT WILL TRACK ACROSS LAKE HURON THIS EVENING AND WILL BE MARKED BY A VEERING OF THE WIND TO THE SOUTHWEST. THE POST FRONTAL COLD AIR ADVECTION IN THE WAKE OF THE FRONT WILL NOT BE SIGNIFICANT ENOUGH TO OVERCOME THE STRONG OVER LAKE STABILITY. THUS WINDS WILL REMAIN MAINLY UNDER 25 KNOTS ON SATURDAY. WINDS WILL QUICKLY DIMINISH SATURDAY NIGHT AS SFC HIGH PRESSURE MOVES OVER THE LAKES. A WARM FRONT WILL SLOWLY LIFT ACROSS THE REGION SUN NIGHT THROUGH MONDAY NIGHT. THE CONTINUED STRONG STABILITY WILL KEEP WINDS AND WAVES IN CHECK. HOWEVER...THERE WILL BE A GOOD CHANCE FOR THUNDERSTORMS THROUGH THE PERIOD. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BT UPDATE.......BT SHORT TERM...JVC LONG TERM....CB/MM 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
759 PM CDT SUN MAY 11 2014 .UPDATE... ISSUED AT 725 PM CDT SUN MAY 11 2014 UPDATED TO INCLUDE 00Z AVIATION DISCUSSION BELOW. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 355 PM CDT SUN MAY 11 2014 EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH RAP 500MB HEIGHTS AND WINDS IDENTIFIED A VIGOROUS SHORTWAVE ROTATING OVER THE 4-CORNERS REGION...WITH AN MCS ONGOING IN EASTERN IA. VISIBLE SATELLITE SHOWED CLEARING BEHIND THIS MCS...AND THE SURFACE OBS HAVE ALREADY REFLECTED THE BOUNDARY LAYER DESTABILIZATION AS TEMPERATURES HAVE INCREASED 5DEG/HR BUT KEPT THE EASTERLY COMPONENT IN THE WIND FIELD. THIS WIND SHIFT MARKED THE STOUT FRONTAL BOUNDARY WHICH WILL BE THE FOCUS FOR TORNADOES LATER THIS AFTERNOON ACROSS EASTERN NE AND WESTERN IA. TEMPERATURES WERE IN THE MID 80S SOUTH OF THIS WARM FRONT WITH SOUTHERLY WINDS...WHILE NORTH OF THE WARM FRONT TEMPERATURES WERE IN THE LOW TO MID 70S WITH DEWPOINTS IN THE MID 60S. THE MLCAPE GRADIENT MIRRORED THE POSITION OF THE EAST/WEST ORIENTED WARM FRONT...BUT INSTABILITY WAS BUILDING WELL NORTH OF THE FRONT AS EVIDENT BY THE 3HR SBCAPE CHANGE ON THE SPC MESOANALYSIS PAGE. THE FINAL POSITION OF THE WARM FRONT WILL DICTATE WHERE THE SURFACE BASED STORMS ARE...AND THUS THE BEST THREAT FOR TORNADOES. AT THIS TIME IT APPEARS THAT THE THREAT WILL REMAIN WELL SOUTH OF THE CWA. HOWEVER...THE LAST FEW RUNS OF THE HRRR AND HOPWRF INDICATE THAT A FEW ELEVATED STORMS ARE EXPECTED AFTER 00Z ACROSS THE SOUTHERN PART OF THE FORECAST AREA. THESE STORMS WILL HAVE 1000-1500J/KG OF MUCAPE TO WORK WITH DEEP SHEAR FAVORABLE FOR ORGANIZED CONVECTION. A FEW STORMS WILL HAVE THE POTENTIAL FOR PRODUCE SEVERE HAIL...MAINLY ALONG THE I-90 CORRIDOR. HEAVY RAIN IS ALSO A THREAT...PERHAPS MORESO THAN THE SEVERE WEATHER. AT THIS TIME...IT APPEARS THAT THE HEAVIEST RAINFALL WILL FALL JUST SOUTH AND EAST OF THE FORECAST AREA ALONG A LINE FROM OMAHA TO LA CROSSE WI. IT IS WITHIN THIS LINE THAT A HP SUPERCELLS ARE EXPECTED WHICH WILL BE CAPABLE OF PRODUCING 2-3IN/HR RAINFALL RATES AND FLASH FLOODING GIVEN THE RAINFALL THAT OCCURRED EARLIER THIS MORNING. IN OUR CWA...WE DID NOT HAVE THE MORNING RAINFALL...AND SUPERCELLS APPEAR LESS LIKELY...SO ALTHOUGH WE MAY GET A QUICK 1-2 INCHES OF RAIN WITH A FEW OF THE HEAVIER CELLS...THIS IS ABOVE FLASH FLOOD GUIDANCE. THEREFORE HAVE OPTED TO HOLD OFF ON A FLOOD WATCH FOR NOW. TO TIE BACK INTO THE HIRES MODELS...THE PROGRESSIVE NATURE OF THE EASTWARD MOVING STORMS ALSO SUPPORTS NOT ISSUING A FLOOD WATCH. THERE WILL BE A LULL IN THE PRECIP ACROSS CENTRAL MN AS THE SURFACE LOW TRACKS NORTHEASTWARD OVERNIGHT. MEANWHILE LIGHT RAIN WILL CONTINUE ACROSS THE WESTERN CWA IN THE DEFORMATION AREA OF THE UPPER LEVEL WAVE. FORECAST MODELS SHOW THE POTENTIAL FOR SOME CONVECTION REDEVELOPING IN THE WARM SECTOR OF THE SURFACE LOW ACROSS EASTERN MN AND WESTERN WI...SO TRIED TO REFLECT THAT IN THE AFTERNOON POP GRIDS. THESE STORMS DO HAVE THE POTENTIAL TO BE SEVERE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 355 PM CDT SUN MAY 11 2014 NOT MUCH IN THE WAY OF CHANGE TO THE EXTENDED PORTION OF THE FORECAST...WITH THE UPCOMING WEEK BEING MARKED BY COOL TEMPERATURES AND PERIODIC SCATTERED LIGHT SHOWERS AS A DEEPLY AMPLIFIED LONGWAVE TROUGH PIVOTS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGIONS. THE BEGINNING OF THE LONG TERM PERIOD /MONDAY NIGHT/ WILL FEATURE RAIN SHOWERS WINDING DOWN AS THE LOW LIFTS TO LAKE SUPERIOR. ADDITIONAL RAINFALL AMOUNTS SHOULD BE AROUND A COUPLE TENTHS OF AN INCH OR LESS. TUESDAY THROUGH FRIDAY BRINGS CYCLONIC FLOW WITH COOLER THAN NORMAL TEMPERATURES AND THE POTENTIAL FOR OCCASIONAL SCATTERED SHOWERS AS THE TROUGH BLANKETS THE REGION. HIGHS WILL BE IN THE 50S AND LOWS WILL DIP INTO THE LOWER 30S AND 40S. THE POTENTIAL FOR FROST LOOKS TO BE TUESDAY THROUGH THURSDAY NIGHTS. TEMPERATURES MODERATE NEXT WEEKEND AS WESTERN UPPER RIDGING BUILDS INTO THE CENTRAL CONUS. HIGHS IN THE 60S LOOK LIKE A GOOD BET FOR NEXT WEEKEND...ALTHOUGH A FEW SHOWERS MAY BE LURKING ON SUNDAY IF THE ECMWF SOLUTION VERIFIES /WHICH INDICATES A TROUGH WILL BUST IN FROM THE PACIFIC NORTHWEST AND BREAK DOWN THE RIDGE/. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 725 PM CDT SUN MAY 11 2014 NWD MOVG WMFNT WILL SPREAD SHWRS/TSTMS ACRS THE REGION THRU THE REST OF THE EVENING INTO THE OVERNIGHT HRS. THIS PRESENTS THE FIRST ISSUE OF THE 12/00Z TAFS - TIMING OF TSRA. INITIAL RADAR TRENDS FOLLOW LOCAL MODEL INITIALIZATIONS SO EXTRAPOLATING THAT BRINGS CONVECTION INTO ALL SITES EXCEPT KAXN AS THE WMFNT LOOKS TO HOLD OFF PUSHING INTO WRN MN...SO THE REMAINDER OF THE TAF SITES DO HAVE A BRIEF WINDOW DURING WHICH IFR CONDS DUE TO TSTMS LOOKS TO OCCUR...MAINLY UP THRU 07Z IN MN AND IN THE 04Z-10Z TIMEFRAME IN WI. THOUGH THE REDUCTION IN VSBY WILL BE DUE TO PRECIP INTENSITY...THERE IS A GOOD LIKELIHOOD OF FLIGHT COND REDUCTION DUE TO LOW STRATUS...WHICH IS THE NEXT ISSUE. AFTER THE PRECIP ENDS LATE THIS EVENING INTO THE OVERNIGHT...WINDS WILL DROP OFF TO ARND 5 KT OR SLIGHTLY LESS WITH VRBL DIRECTION...AND WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE...LOW STRATUS WILL BE AN ISSUE. WOULD THINK MORE FOG IF WINDS WENT CALM...BUT SFC WINDS LOOK TO STAY 4-5 KT SO AM THINKING MORE LOW STRATUS WITH LESSER FOG. THE LAST ISSUE THEN BECOMES TIMING ANOTHER PRECIP WINDOW LATE TMRW MRNG INTO TMRW AFTN ON THE BACKSIDE OF THE DEPARTING LOW PRES CENTER...WHEN WINDS WILL SHIFT ARND TO W AND NW. NO CONVECTION XPCTD AT THAT TIME...BUT LOW STRATUS WILL CONTINUE THRU TMRW. KMSP...VFR TO START AND INTO THE FIRST COUPLE HRS OF THE TAF THEN CONDITIONS DETERIORATE LATER THIS EVENING AS SHWRS/TSTMS IMPACT THE TERMINAL. MAINLY VFR BUT OCNL TSTMS MOVG ACRS THE AREA MAY WELL DROP VSBY INTO IFR ALONG WITH CIGS SUB-1700 FT. ONCE THE PRECIP ENDS AND WINDS DROP OFF SLIGHTLY...LOW STRATUS WILL BECOME AN ISSUE...LEAVING CEILINGS BELOW 1700 FT...AND POSSIBLY UNDER 1000 FT...FOR MUCH THE MORNING PUSH INTO MIDDAY MON. CONDS IMPROVE SLIGHTLY TMRW AFTN WHEN ANOTHER BATCH OF -RA IS XPCTD BUT CIGS ARE STILL LIKELY TO REMAIN BELOW 1700 FT THRU TMRW EVE. WINDS SHIFT TO WLY TMRW AFTN AND INCRS TO ARND 10 KT. /OUTLOOK FOR KMSP/ TUE...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 15-20 KTS. WED...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 5-15 KTS. THU...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS NW 5-15 KTS. && .HYDROLOGY... ISSUED AT 355 PM CDT SUN MAY 11 2014 AT THIS TIME RIVER FLOODING APPEARS TO BE THE PRIMARY CONCERN MAINLY IN WESTERN WI AND THE MAINSTEM OF THE MISSISSIPPI RIVER. ANOTHER ROUND OF 1 TO 2 INCHES OF BASIN-WIDE RAINFALL IS EXPECTED OVER THE NEXT 24 HRS. AT THIS TIME...THE THREAT FOR THE HEAVIEST RAIN AND FLASH FLOODING APPEARS TO BE ACROSS IOWA...SO NOT ANTICIPATING ANY FLASH FLOODING IN MN OR WI. IF IT WERE TO HAPPEN...IT WOULD BE IN FAR SOUTHERN MN. LASTLY, IF THE FORECAST RAINFALL AMOUNTS TREND HIGHER THAN CURRENTLY EXPECTED...THE FLOODING POTENTIAL WILL INCREASE AS WELL. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE...JPC SHORT TERM...JRB LONG TERM...LS AVIATION...JPC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
234 PM CDT SAT MAY 10 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 235 PM CDT SAT MAY 10 2014 SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE FORECAST AREA THROUGH MIDNIGHT. THE THREAT FOR SEVERE WEATHER IS LOW...AND THE BEST CHANCE FOR HAIL AND WIND EXISTS ACROSS WEST CENTRAL AND SOUTHWEST MINNESOTA. WEAK SURFACE LOW NEARLY CO-LOCATED WITH NICE SHORTWAVE DIGGING IN ACROSS SOUTH DAKOTA THIS AFTERNOON. THE COMBINATION OF SURFACE HEATING...WEAK MOISTURE TRANSPORT AND LIFT IS PROMOTING CONVECTIVE INITIATION ACROSS SOUTHWEST MINNESOTA AND NORTHERN IOWA. THE CURRENT SHOWERS EXTEND ALONG A NW-SE AXIS OF HIGHER PWATS /0.70"-0.90"/ PER THE 19Z SURFACE RAP ANALYSIS. THE SBCAPE IS WEAK BUT THE APPROACH SHORTWAVE IS HELPING TO STEEPEN THE MID LEVEL LAPSE RATE TO 7-7.5C/KM IN WESTERN MINNESOTA. THE UPPER FLOW IS PRETTY WEAK BUT THERE SHOULD BE ENOUGH FORCING AND SHEAR TO PROMOTE MULTI-CELL CONVECTIVE MODE AND A SLIGHT CHANCE FOR HAIL AND GUSTY WINDS WITH THE STRONGEST UPDRAFTS. THIS IS ESPECIALLY TRUE FROM 4-7PM WHERE THE SFC-6KM MAX LAYER THETA-E DIFFERENCE IS BETWEEN -15C AND -20C IN WESTERN MN. FARTHER EAST IN EASTERN MN AND WESTERN WI...THE CONVECTIVE POTENTIAL IS LOWER /ALTHOUGH THERE SHOULD STILL BE A HEALTHY BAND OF SHOWERS WITH GOOD VERTICAL EXTENT AND IN-CLOUD LIGHTNING/. MANY OF THE HI-RES WRF SIMULATIONS /SPC...HOPWRF...NCEP/ HAVE THE RAIN CLEARING MN BY ABOUT 9PM AND WESTERN WI BY ABOUT MIDNIGHT. THERE WILL BE A BREAK IN THE PRECIP BEFORE ISENTROPIC LIFT WITH THE STRENGTHENING SOUTHERN PLAINS LOW STARTS TO SPREAD SHOWERS AND STORMS INTO SOUTHERN MINNESOTA BY TOMORROW AFTERNOON. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 235 PM CDT SAT MAY 10 2014 THE LONG TERM PORTION OF THE FORECAST WILL BE ACTIVE FROM THE GET- GO...WITH A SURFACE TROUGH EXPECTED TO BE NOSING INTO SOUTHERN MN AT 00Z MONDAY. THUNDERSTORMS /LIKELY SEVERE/ ARE EXPECTED TO BE ONGOING TO THE SOUTH...WITH THE THREAT FOR STRONG THUNDERSTORMS SHIFTING NORTH INTO SOUTH CENTRAL/EAST MN AND WEST CENTRAL WI ON SUNDAY NIGHT AS THE INSTABILITY GRADIENT LIFTS NORTH. PRECIPITABLE WATER VALUES INCREASE TO AROUND 200 PERCENT OF NORMAL /1.5 INCHES/...SO HEAVY RAIN PRODUCING THUNDERSTORMS ARE CERTAINLY A POSSIBILITY AS LLVL MOISTURE TRANSPORT ENSUES SUNDAY NIGHT AND MONDAY. COULD STILL POTENTIALLY SEE AMOUNTS CURTAILED A BIT DUE TO THE CONVECTION TO THE SOUTH...BUT STILL THINK 1-2 INCH TOTALS ARE QUITE POSSIBLE BETWEEN SUNDAY EVENING AND MONDAY MORNING ALONG THE INTERSTATE 90 CORRIDOR OF SOUTH CENTRAL AND SOUTHEAST MN...AND EAST OF INTERSTATE 35 FROM THE TWIN CITIES ACROSS WEST CENTRAL WI. MONDAY AFTERNOON/EVE WILL BE ANOTHER WINDOW OF TIME WHEN STRONG TO SEVERE STORMS COULD SKIRT THE SOUTHEASTERN BORDER OF THE FORECAST AREA...NAMELY ACROSS WEST CENTRAL WI. MONDAY NIGHT AND TUESDAY THE MID LEVEL TROUGH PIVOTS ACROSS THE AREA AND SUPPLIES ANOTHER ROUND OF SHOWERS...ALTHOUGH THE THUNDER POTENTIAL WILL HAVE LOWERED NOTABLY AND COVERAGE SHOULD BE MORE SCATTERED IN NATURE. MODEL TRENDS FOR WEDNESDAY...PARTICULARLY THE 10.12Z ECMWF WERE TO KEEP THE NORTHERN AND SOUTHERN STREAM ENERGY A BIT MORE DISJOINTED...HENCE LEAVING THE LOCAL AREA IN BETWEEN THE MAIN AREAS OF FORCING. HOWEVER...COULD STILL SEE A FEW INSTABILITY SHOWERS ON WEDNESDAY THROUGH THE END OF THE WEEK AS THE NORTHERN STREAM TROUGH SAGS INTO THE UPPER MIDWEST AND GREAT LAKES REGION. NO SURPRISE THAT TEMPERATURES WILL BE COOL NEXT WEEK...AS H85 TEMPERATURES FLIRT WITH 0 CELSIUS FROM TUESDAY THROUGH FRIDAY. WILL NEED TO MONITOR THE POTENTIAL FOR FROST DURING THE OVERNIGHT PERIODS...WITH THE GROWING SEASON NEARING. BETTER NEWS /IN THE FORM OF WARMER TEMPERATURES/ IS EXPECTED TO ARRIVE FOR NEXT WEEKEND...AS THE TROUGH LIFTS TO HUDSON BAY AND WESTERN RIDGING BUILDS TOWARD THE CENTRAL CONUS. EXPECT TO SEE 60S BACK IN THE FORECAST FOR NEXT SATURDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 148 PM CDT SAT MAY 10 2014 SHOWERS AND THUNDERSTORMS WILL CONTINUE TO EXPAND TO THE NORTHEAST OVER THE NEXT SEVERAL HOURS. THUNDER CHANCES TODAY ARE DEFINITELY BETTER AT KAXN/KRWF/KSTC...THAN THE TAF SITES TO THE EAST. VFR CONDITIONS SHOULD STILL DOMINATE OUTSIDE MVFR CEILINGS AND BRIEF MVFR/IFR VISIBILITY WITH HEAVIER DOWNPOURS OF RAIN. THE RAIN WILL CLEAR THIS EVENING. KMSP... WE ARE HIGHLY CONFIDENT IN RAIN LATE THIS AFTERNOON AND EARLY EVENING...BUT THE THREAT FOR THUNDER IS ADMITTEDLY BETTER TO THE WEST OF THE AIRPORT. WE STILL EXPECT HEALTHY SHOWER WITH AT LEAST IN CLOUD LIGHTNING OVER KMSP BETWEEN 5-7 PM. /OUTLOOK FOR KMSP/ SUN...MVFR POSSIBLE. LIKELY -SHRA. WINDS SW TO NW 10-15KTS. MON...MVFR LIKELY. IFR POSSIBLE. LIKELY -SHRA. WINDS NW 10KTS. TUE...MVFR POSSIBLE. ISO-SCT -SHRA. WINDS W-NW 15-25KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...CLF LONG TERM...LS AVIATION...CLF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1225 AM CDT SAT MAY 10 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 252 PM CDT FRI MAY 9 2014 MAIN FORECAST CONCERNS WILL BE CHANCE FOR SPRINKLES AND LATE TONIGHT AND INTO SATURDAY MORNING AND TEMPERATURES THROUGH THE PERIOD. A WEAK SURFACE HIGH PRESSURE SYSTEM IS DRIFTING THROUGH THE CENTRAL PLAINS TODAY. THIS HAS KEPT SKIES MOSTLY CLEAR AND WINDS FAIRLY LIGHT AND VARIABLE. THE SURFACE HIGH IS EXPECTED TO SLIDE TO THE SOUTHEAST LATE THIS AFTERNOON AND THIS EVENING. WINDS WILL CONTINUE TO TURN TO THE SOUTHWEST OR WEST THROUGH THE EVENING HOURS. AN UPPER LEVEL WAVE WILL MOVE INTO THE AREA TONIGHT. SO FAR THE LOWER LAYERS ARE FAIRLY DRY...BUT BOTH THE GFS AND NAM BRING IN SOME SPOTTY PRECIPITATION TONIGHT AND THE HRRR AND WRF ALSO HINT AS SOMETHING VERY SPOTTY ACROSS THE AREA. WITH THE DRY LOWER LEVELS HAVE KEPT A FEW SPRINKLES MAINLY IN THE NORTHERN PART OF THE FORECAST AREA BECAUSE CONFIDENCE IS LOW THERE WOULD BE ANYTHING MEASURABLE. A WEAK COLD FRONT WILL MOVE INTO THE AREA LATE TONIGHT...MOVING THROUGH THE AREA SATURDAY MORNING. FOR A FEW HOURS BEHIND THE FRONT THERE WILL BE A LITTLE BREEZIER CONDITIONS...BUT BEFORE MID AFTERNOON THE WINDS START TO DIMINISH A LITTLE. EVEN BEHIND THE COLD FRONT THE TEMPERATURES ON SATURDAY WILL BE FAIRLY WARM. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 252 PM CDT FRI MAY 9 2014 GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST QUASI- ZONAL UPPER TROPOSPHERIC FLOW WILL EXIST ACROSS MUCH OF THE CONUS AT 00Z SUNDAY...ALTHOUGH A STRENGTHENING UPPER TROPOSPHERIC SHORT WAVE OVER THE SOUTHWESTERN CONUS WILL BEGIN TURNING THE FLOW OVER OUR AREA MORE SOUTHWESTERLY BY 12Z SUNDAY. EVENTUALLY AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS IS EXPECTED TO DEVELOP FROM SOUTH CENTRAL CANADA INTO THE SOUTHWESTERN CONUS BY 00Z MONDAY...WITH THE TROUGH AXIS EXPECTED TO MOVE EAST ACROSS ACROSS OUR AREA MONDAY NIGHT INTO TUESDAY...RESULTING IN NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA TUESDAY NIGHT ONWARD. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS EXPECTED ACROSS WESTERN KANSAS AND EASTERN COLORADO AT 00Z SUNDAY. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST...LIKELY NEARING NORTHEAST KANSAS BY 00Z MONDAY AND THE UPPER MISSISSIPPI VALLEY BY 00Z TUESDAY. SO ALTHOUGH THE LOWER TROPOSPHERIC FLOW ACROSS OUR AREA WILL START THE LONG TERM FORECAST PERIOD FROM THE EAST/SOUTHEAST...A TRANSITION TO THE NORTHEAST IS EXPECTED ACROSS MUCH OF THE AREA DURING THE DAY SUNDAY...AND TO THE NORTHWEST SUNDAY NIGHT THROUGH MUCH OF THE REST OF THE LONG TERM FORECAST PERIOD. THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST A 50-60KT JET STREAK JUST ABOVE THE BOUNDARY LAYER WILL PROMOTE ENOUGH THERMAL ADVECTION FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE CWA SATURDAY NIGHT ...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA WHERE THERMAL ADVECTION...AS WELL AS MOISTURE CONVERGENCE...WILL BE ENHANCED. GIVEN THIS...WENT AHEAD WITH 20-70% POPS ACROSS MUCH OF THE CWA SATURDAY NIGHT...WITH THE HIGHEST POPS RELEGATED ACROSS OUR EAST. AT THIS TIME ANY CONVECTION THAT IS REALIZED SATURDAY NIGHT IS EXPECTED TO REMAIN WEAK. ANY OVERNIGHT CONVECTION SHOULD DEPART TO THE EAST/NORTHEAST BY DAYBREAK SUNDAY AS THE LOWER TROPOSPHERIC JET STREAK ALSO SHIFTS TO THE EAST. THIS MAY ALLOW FOR A BREAK IN PRECIPITATION AT SOME POINT SUNDAY MORNING...BUT POPS STILL REMAIN INTACT FOR THE ENTIRE CWA ON SUNDAY AS THERMAL ADVECTION AHEAD OF THE APPROACHING UPPER TROPOSPHERIC TROUGH INCREASES. AS THE AFOREMENTIONED SURFACE LOW MOVES INTO NORTHEASTERN KANSAS SUNDAY AFTERNOON AND EVENING...AN ASSOCIATED LOWER TROPOSPHERIC BAROCLINIC ZONE IS EXPECTED TO BACK NORTHWEST AS A WARM FRONT...PERHAPS PUSHING INTO OUR EXTREME EAST/SOUTHEASTERN CWA. LOWER TROPOSPHERIC CONVERGENCE AND RESULTANT LIFT ALONG THIS BAROCLINIC ZONE...ALONG WITH INCREASING SYNOPTIC- SCALE OMEGA DUE TO INCREASING UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH...APPEARS AS THOUGH THEY WILL BE SUFFICIENT FOR CONVECTIVE INITIATION SUNDAY AFTERNOON AND EVENING. SOME OF THIS CONVECTION COULD CERTAINLY BE REALIZED OVER OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING. THE BAROCLINIC ZONE SHOULD QUICKLY DEPART OUR AREA TO THE EAST/SOUTHEAST SUNDAY EVENING AS THE SURFACE LOW MOVES NORTHEAST...THUS ALLOWING A MUCH COOLER AND DRIER LOWER TROPOSPHERIC AIR MASS INTO THE AREA. THIS WILL RESULT IN RAPIDLY DECREASING POTENTIAL INSTABILITY THUS ELIMINATING ANY CHANCE OF DEEP CONVECTION ACROSS OUR AREA. THAT BEING SAID...CONTINUED THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH APPEARS IT WILL STILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION HEADING INTO THE REMAINDER OF SUNDAY NIGHT AND EVEN MONDAY. AS A RESULT...POPS REMAIN INTACT ACROSS MUCH OF THE CWA SUNDAY NIGHT INTO MONDAY. BY MONDAY NIGHT...UPPER TROPOSPHERIC THERMAL ADVECTION SHOULD DIMINISH AS THE TROUGH AXIS BEGINS CLEARING THE AREA. DRY CONDITIONS ARE CURRENTLY FORECAST MONDAY NIGHT THROUGH WEDNESDAY AS A RESULT. WEDNESDAY NIGHT INTO THURSDAY...THERE ARE INDICATIONS FROM THE OPERATIONAL GFS...AND TO A LESSER EXTENT THE NAM...OF A WEAK UPPER TROPOSPHERIC PERTURBATION MOVING ACROSS THE REGION AND PERHAPS PROVIDING A PERIOD OF LIGHT PRECIPITATION. CONFIDENCE REGARDING THIS FEATURE IS NOT HIGH...BUT ALLBLEND PRESENTED A ~20% POP TO OUR NORTH/NORTHEAST WEDNESDAY NIGHT INTO THURSDAY AND OPTED TO KEEP THIS POP AS IS. GUIDANCE SUGGESTS DEW POINT READINGS WELL INTO THE 60S WILL INFILTRATE MUCH OF EASTERN KANSAS SUNDAY AFTERNOON ON THE WARM SIDE OF THE BAROCLINIC ZONE. THE MOISTURE CONTENT OF THE LOWER TROPOSPHERIC AIR MASS IS NOT EXPECTED TO BE NEARLY AS ROBUST FARTHER NORTHWEST INTO OUR AREA...BUT AGAIN IF THE BAROCLINIC ZONE CAN SNEAK INTO OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING...THEN POTENTIAL INSTABILITY VALUES COULD CERTAINLY CLIMB INTO THE 1000- 2000J/KG RANGE. DEEP LAYER BULK SHEAR VALUES ON THE ORDER OF ~50KTS ARE ALSO FORECAST ACROSS OUR EAST/SOUTHEAST SUNDAY AFTERNOON AND EVENING. SO...ALTHOUGH IT APPEARS THE BULK OF THE SEVERE WEATHER SHOULD REMAIN SOUTH AND EAST OF OUR CWA...IT STILL APPEARS THERE WILL BE A BRIEF WINDOW OF OPPORTUNITY FOR STRONG THUNDERSTORM ACTIVITY ACROSS PORTIONS OF OUR CWA...GENERALLY ALONG AND SOUTHEAST OF A LINE FROM ALMA TO YORK. A THREAT FOR SEVERE WEATHER WILL RESIDE FARTHER SOUTHEAST...GENERALLY ALONG AND SOUTHEAST OF A LINE FROM BELOIT TO HEBRON. WILL GO AHEAD AND MENTION THESE THREATS IN THE HWO FOR SUNDAY. GUIDANCE ALSO SUGGESTS LOWER TROPOSPHERIC PRESSURE RISES POST-FROPA COULD PROVIDE A STRONG LOWER TROPOSPHERIC WIND FIELD ACROSS NORTHWESTERN PORTIONS OF THE CWA SUNDAY AFTERNOON INTO SUNDAY EVENING. GUIDANCE SUGGESTS A SUSTAINED WIND OF 25-30KTS WITH LOCALLY HIGHER GUSTS WILL BE REALIZED AND AS A RESULT...WILL MENTION SUCH CONDITIONS IN THE HWO. A COOLER LOWER TROPOSPHERIC AIR MASS WILL INFILTRATE THE AREA FOLLOWING THE PASSAGE OF THE BAROCLINIC ZONE SUNDAY...WITH HIGHS GENERALLY IN THE 50 ON MONDAY AND IN THE 60S TUESDAY THROUGH FRIDAY. OVERNIGHT LOWS IN THE 40S ARE FORECAST FOR THE MOST PART THROUGH THE LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1219 AM CDT SAT MAY 10 2014 VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD. A SURFACE TROUGH WILL BE WORKING EAST ACROSS THE CENTRAL PLAINS OVERNIGHT AND EARLY SATURDAY MORNING. WINDS WILL BE LIGHT FROM THE SOUTH INITIALLY DURING THE TAF PERIOD...HOWEVER ABOVE THE SFC WINDS WILL BE MUCH STRONGER DUE TO A STRENGTHENING LLVL JET AND INCLUDED A PERIOD OF LLVL WIND SHEAR. BEHIND THE SURFACE BOUNDARY WINDS WILL TRANSITION WESTERLY AND NORTHWESTERLY ON SATURDAY. IN DEEP MIXING WIND GUSTS OVER 20KT ARE POSSIBLE. SFC HIGH PRESSURE WILL BUILD SOUTHEAST BEHIND THE FRONT AND WINDS WILL DROP OFF AND SWITCH NORTHEASTERLY TOWARD THE LATTER TAF HOURS. CLOUDS WILL BE LIMITED TO THE MID/HIGH LEVELS. && .FIRE WEATHER... ISSUED AT 252 PM CDT FRI MAY 9 2014 RELATIVE HUMIDITY LEVELS ARE EXPECTED TO DROP BELOW 25 PERCENT FOR NORTH CENTRAL KANSAS AND FAR SOUTHERN SOUTH CENTRAL NEBRASKA FOR SATURDAY AFTERNOON. DURING THE MORNING THE WINDS WILL BE WEST OR NORTHWEST AT 15 TO 20 MPH WITH GUSTS TO AROUND 25 MPH...BUT BY AFTERNOON...WHEN THE RELATIVE HUMIDITY WILL BE THE LOWEST...THE WINDS WILL HAVE DIMINISHED TO 10 TO 15 MPH WITH GUSTS TO 20 MPH. EXPECT THERE TO ONLY BE A SMALL TIME FRAME WHERE NEAR CRITICAL FIRE DANGER IS EVEN CLOSE. WILL LEAVE IT OUT OF THE HWO AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...BRYANT AVIATION...FAY FIRE WEATHER...JCB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1128 PM EDT SUN MAY 11 2014 .SYNOPSIS... HIGH PRESSURE OFFSHORE WILL MAINTAIN WELL ABOVE NORMAL TEMPERATURES THROUGH THE MIDDLE OF THE UPCOMING WEEK. A COLD FRONT WILL APPROACH THURSDAY BEFORE CROSSING OFFSHORE ON FRIDAY...BRINGING A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS. COOLER TEMPERATURES WILL DEVELOP IN THE WAKE OF THIS COLD FRONT INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1045 PM SUNDAY...RIDGING ALOFT AND ITS AXIS NEARLY OVERHEAD...WILL AMPLIFY-SOME ACROSS THE BI-STATE REGION OVERNIGHT AND INTO THE SHORT TERM PERIOD. THIS WILL DEFLECT ANY S/W TROFS ALOFT TO THE WEST AND NORTH OF THE FA. AT THE SFC...MODEST HIGH PRESSURE CENTERED OFFSHORE AND EAST OF THE CAROLINAS...WILL RIDGE BACK ACROSS THE REGION...AND PREVAIL GOING INTO THE SHORT TERM PERIOD. FOR THE REMAINDER OF THIS EVENING AND OVERNIGHT...THE DIURNALLY INDUCED CONVECTION HAS DISSIPATED LEAVING A FEW OUTFLOW BOUNDARIES ACROSS PORTIONS OF THE FA GOING INTO DAYLIGHT MONDAY. WITH THE MAJORITY OF THE LEFTOVER CONVECTIVE CLOUDINESS DISSIPATING...A SFC BASED INVERSION SHOULD DEVELOP COURTESY OF THE HOURLY NAMBUFR SOUNDINGS. LOW LEVEL STRATUS BELOW 1K FEET WILL DEVELOP ACROSS THE FA VIA LATEST HRRR MODEL RUNS. MIN TEMPS HAVE BEEN MASSAGED UPWARDS ESPECIALLY WITH LOW LEVEL STRATUS OVERTAKING THE FA AND SFC DEWPOINTS REMAINING WELL INTO THE 60S ACROSS THE MAJORITY OF THE FA. PATCHY TO AREAS OF FOG WILL ALSO BE ADVERTISED ACROSS THE FA...FOR MAINLY THE HOURS BETWEEN MIDNIGHT TO JUST AFTER SUNRISE. COULD BE ONE OF THOSE NIGHTS WHERE LOW LEVEL STRATUS AND FOG DUEL WITH ONE ANOTHER IN SEEING WHO WILL PREVAIL OVER THE OTHER. PREVIOUS DISCUSSION............................................ AS OF 300 PM SUNDAY...ISOLATED TO WIDELY SCATTERED SHOWERS ARE BREAKING OUT ACROSS THE FORECAST AREA EARLY THIS AFTERNOON. SO FAR HAVE NOTED ONLY ONE BRIEF THUNDERSTORM OVER COASTAL GEORGETOWN COUNTY. WITH A MODERATELY UNSTABLE ATMOSPHERE AND MOIST LOW LEVELS EXPECT THIS ACTIVITY TO CONTINUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY EVENING. BOTH GFS AND NAM INDICATE COLUMN MOISTURE BECOMING MORE SHALLOW AFTER SUNSET AND WITH AN UPPER RIDGE BUILDING IN SEE LITTLE CHANCE FOR SIGNIFICANT OVERNIGHT PRECIPITATION. SO...AS THIS ACTIVITY SEEMS DIURNALLY DRIVEN WITH NO STRONG FORCING MECHANISM PRESENT...EXPECT CONVECTION TO FADE WITH THE SETTING SUN AND TO BE OVER WITH BY MIDNIGHT. HAVE CONTINUED RECENT TREND OF FORECASTING MINIMUM TEMPERATURES A FEW DEGREES ABOVE GUIDANCE. THIS METHOD HAS BEEN VERIFYING WELL AGAINST GUIDANCE RECENTLY AND GIVES US OVERNIGHT MINIMUMS IN THE MID 60S FOR MOST PLACES. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...SUMMERTIME PATTERN AMPLIFIES DURING THE BEGINNING OF THE WEEK THANKS TO A STRENGTHENING 5H RIDGE. THIS WILL DRIVE TEMPERATURES WELL INTO THE 80S TO AROUND 90 MONDAY AND TUESDAY AWAY FROM THE COAST...WITH LOW 80S ANTICIPATED AT THE BEACHES. THESE VERY WARM TEMPS...COMBINED WITH STILL COOL OCEAN TEMPS...AND A WEAK GRADIENT BOTH AT THE SURFACE AND ALOFT...SHOULD ALLOW DECENT INLAND PENETRATION OF THE SEA BREEZE BOTH DAYS. THIS WILL HAVE ONLY LIMITED IMPACT ON HIGHS THOUGH SINCE TEMPS WILL SOAR QUICKLY DURING LATE MORNING EARLY AFTN...THANKS TO LOWS ONLY FALLING INTO THE MID/UPR 60S...70 AT THE COAST. MORE QUESTIONABLE PORTION OF THE FORECAST INVOLVES CONVECTIVE POTENTIAL THROUGH EARLY WEEK. GUIDANCE IS STUBBORNLY DEPICTING SCATTERED SHOWERS/TSTMS BOTH MONDAY AND TUESDAY AFTNS...FOCUSED PRIMARILY ON THE SEA BREEZE. SPC HAS GENERAL RISK ACROSS THE AREA BOTH DAYS AS WELL. AM STRUGGLING TO FIND REASONS TO INCLUDE CONVECTION IN THE FORECAST...OTHER THAN DEWPOINTS WELL INTO THE 60S AND STEEP SURFACE-BASED LAPSE RATES. HOWEVER...PRETTY MUCH EVERYTHING ELSE POINTS TO THE NEXT TWO DAYS BEING DRY. 500MB RIDGE AXIS SITS NEARLY OVERHEAD...PROVIDING A SUBSIDENT LID WITH VERY WEAK MID-LEVEL LAPSE RATES. 700MB RIDGE REMAINS ANCHORED OVERHEAD AS WELL...FORCING ANY MOISTURE AROUND TO THE WEST OF THE AREA...WHICH IS ALSO ECHOED BY WEAK 850-700MB MOISTURE TRANSPORT VECTORS AND DRYING FORECAST SOUNDINGS. LCL`S ARE AT THE TOP OF WHATEVER RESIDUAL MOIST LAYER EXISTS MONDAY AND TUESDAY...SO UPDRAFTS SHOULD SUFFER FROM SIGNIFICANT DRY AIR ENTRAINMENT...FURTHER LIMITING CONVECTIVE POTENTIAL. STILL...INHERITED HAS SCHC MONDAY AND SURROUNDING WFO`S HAVE AT LEAST THAT...SO WILL KEEP SCHC MONDAY FOR ISOLATED SHOWERS...BUT DROP POP TO SILENT ON TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...THE BIG WEATHER MAKER IN THE LONG TERM WILL BE AN EASTWARD-MOVING COLD FRONT THURSDAY...PUSHED ALONG BY A FULL LATITUDE UPPER TROUGH EXTENDING FROM HUDSON BAY TO THE GULF COAST. THE WESTERN EXTENSION OF THE BERMUDA HIGH WILL COVER THE AREA WEDNESDAY. RELATIVELY STABLE ONSHORE WINDS AND PLENTY OF DRY AIR ASSOCIATED WITH THE DEEP-LAYER RIDGING SHOULD KEEP THINGS MOSTLY SUNNY AND DRY WITH HIGHS IN THE UPPER 80S INLAND AND AROUND 80 ON THE BEACHES. PRESSURES WILL BEGIN TO FALL WEDNESDAY NIGHT AS THE AFOREMENTIONED FRONT CROSSES THE LOWER MISSISSIPPI VALLEY. INCREASING SOUTHERLY FLOW WILL BEGIN TO MOISTEN OUR AIRMASS...AND PRECIPITABLE WATER VALUES SHOULD CLIMB FROM AROUND 1 INCH WEDNESDAY TO 1.5 INCHES BY LATE WEDNESDAY NIGHT. INTEGRATED COLUMN MOISTURE PEAKS JUST AHEAD OF THE FRONT THURSDAY EVENING WITH PW VALUES NEAR 1.9 INCHES. 850 MB WINDS DO NOT BECOME PARTICULARLY STRONG...20-30 KT DEPENDING ON YOUR MODEL...AND KINEMATIC FIELDS ARE NOT OVERLY CONCERNING FOR A SEVERE WEATHER RISK. GIVEN MODEST FORECAST INSTABILITY (CAPE 1000-1500 J/KG) AND SUCH MOIST SOUNDINGS THE LARGEST CONCERN COULD BE LOCALLY HEAVY RAIN AND PERHAPS A WET DOWNBURST IN STRONGER CELLS. THE BULK OF THE LATEST OPERATIONAL MODEL RUNS SHOW THE COLD FRONT PUSHING ACROSS THE EASTERN CAROLINAS THURSDAY NIGHT...HOWEVER THE 12Z CANADIAN AS WELL AS ABOUT 25% OF THE 00Z & 06Z GFS ENSEMBLE MEMBERS ARE SLOWER MOVING THE BOUNDARY OFF THE COAST. I HAVE THEREFORE MAINTAINED A 30-40 POP INTO FRIDAY. DRY WEATHER SHOULD ALMOST CERTAINLY DEVELOP BY FRIDAY EVENING LASTING INTO SATURDAY AS HIGH PRESSURE BUILDS OVER THE CAROLINAS. THE MOST NOTABLE FEATURE ABOUT THIS INCOMING AIRMASS WILL BE HOW MILD TEMPERATURES WILL BE COMPARED TO WHAT WE HAVE EXPERIENCED THE PAST WEEK. WITH 850 MB TEMPS PROGGED +8C TO +10C BOTH FRIDAY AND SATURDAY...HIGHS SHOULD REMAIN IN THE UPPER 70S FOR MOST AREAS WITH LOWS IN THE 50S. BY NEXT SUNDAY BOTH THE GFS AND ECMWF SHOW THE TRAILING END OF A POTENT UPPER LEVEL DISTURBANCE MOVING ACROSS THE CAROLINAS. EVEN WITH NO LOW-LEVEL GULF OR ATLANTIC INFLOW...MODELS SHOW ENOUGH PACIFIC MOISTURE COMING ACROSS AT AND ABOVE 850 MB THAT A 30 POP FOR SHOWERS APPEARS WARRANTED. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...THE RADAR IS QUIET THIS EVENING AS DIURNAL CONVECTION FROM EARLIER TODAY HAS DISSIPATED. SATELLITE IMAGERY SHOWS MID LEVEL CLOUDS ARE RAPIDLY DIMINISHING...WHICH ENHANCES THE POTENTIAL FOR MVFR/IFR FOG OVERNIGHT. WEAK PRESSURE GRADIENT SHOULD ALLOW WINDS TO BECOME CALM LATER TONIGHT...AND UPPER 60S DEWPOINTS INDICATE THE LOW LEVEL ENVIRONMENT IS PRIMED FOR FOG. VSBYS WILL LIKELY DROP FIRST AT KCRE/KMYR GIVEN THEIR SMALL TEMP/DEWPOINT SPREADS. THESE TERMS COULD SEE IFR VSBYS DEVELOP BEFORE 06Z. ELSEWHERE...IFR FOG IS EXPECTED TO HOLD OFF UNTIL AFTER 06Z. GIVEN THE AGREEMENT IN FCST SOUNDINGS AND MAV/MET GUIDANCE...AT LEAST PERIODS OF IFR VSBYS APPEAR LIKELY AT ALL TAF SITES OVERNIGHT. THE MID LEVEL MOISTURE THAT HELPED FUEL STORMS TODAY WILL BE DISPLACED SOUTHWARD TOMORROW. THEREFORE... EXPECT VFR ON MONDAY WITH SCT AFTN CU AND SOUTH WINDS AOB 10 KTS. EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR FOG/STRATUS IS POSSIBLE THROUGH THURSDAY. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY. SHOWERS/TSTMS EXPECTED THURSDAY THROUGH EARLY FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM SUNDAY...ORIENTATION OF THE SFC RIDGE AXIS EXTENDING ACROSS THE AREA WATERS FROM THE HIGHS CENTER OFFSHORE AND EAST OF THE CAROLINAS...WILL DETERMINE WIND DIRECTIONS. AT THIS POINT...MODELS INDICATE WINDS BECOMING SW-WSW NORTH OF LITTLE RIVER INLET...AND S TO SSW SOUTH OF THIS INLET. THIS TO OCCUR AFTER THE DEMISE OF THE SEA BREEZE CIRCULATION. THE LOOSE SYNOPTIC SFC PRESSURE GRADIENT WILL KEEP WIND SPEEDS AT OR BELOW 10 KT. SIGNIFICANT SEAS WILL RUN 2 TO OCCASIONALLY 3 FT...AND MAINLY BE COMPRISED OF WIND DRIVEN WAVES WITH PERIODS OF 5 TO 6 SECONDS. AT THIS POINT...THE 11 TO 13 SECOND PERIOD EASTERLY GROUND SWELL REMAINS NEGLIGIBLE FOR ANY INPUT INTO THE SIGNIFICANT SEAS. PREVIOUS DISCUSSION.......................... AS OF 300 PM SUNDAY...MANAGEABLE MARINE CONDITIONS EXPECTED. EXPECT A LIGHT SW WIND FLOW ACROSS THE WATERS THROUGH TONIGHT. SEAS GENERALLY 2-3 FEET...IN A MIX OF SSW WAVES 1-2 FEET EVERY 4-5 SEC AND SE WAVES 1-2 FT EVERY 7-8 SECONDS. ISOLATED TSTMS ARE POSSIBLE NEAR SHORE THIS AFTERNOON INTO THIS EVENING...AND THE MOTION WILL BE FROM SW TO NE. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...PRIMARILY UNIFORM WIND/WAVE CONDITIONS DURING THE SHORT TERM AS BERMUDA HIGH PRESSURE SITS OFFSHORE INTO MID-WEEK. RETURN FLOW AROUND THIS HIGH PRODUCES SW WINDS OF 10-15 KTS DURING THE DAY...AND 5-10 KTS AT NIGHT. THE EXCEPTION WILL BE IN THE NEAR-SHORE WATERS WHERE A SEA BREEZE WILL CAUSE WINDS TO GUST UP TO 20 KTS FOR A FEW HOURS EACH AFTN/EVE. THESE WINDS COMBINED WITH THE LONG FETCH AROUND THE HIGH PRESSURE WILL BUILD SEAS TO 2-3 FT THROUGH THE PERIOD...WITH A 5 SEC S/SW WIND WAVE AND A 7 SEC SE GROUND SWELL COMPRISING THE SPECTRUM. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...HIGH PRESSURE JUST OFFSHORE WEDNESDAY SHOULD PROVIDE GENTLE ONSHORE WINDS AND DRY WEATHER. MOISTURE WILL INCREASE THURSDAY AHEAD OF A COLD FRONT...EXPECTED TO MOVE OFF THE COAST FRIDAY MORNING. THIS FRONT SHOULD BE PRECEDED BY WAVES OF SHOWERS AND EMBEDDED THUNDERSTORMS...ESPECIALLY LATE THURSDAY AFTERNOON INTO THURSDAY NIGHT. ONCE THE FRONT MOVES FARTHER OFFSHORE FRIDAY... CLEARING CONDITIONS ARE EXPECTED ALONG WITH BREEZY NORTH TO NORTHWEST WINDS. AT THIS TIME IT APPEARS CONDITIONS SHOULD REMAIN BELOW ADVISORY THRESHOLDS...ALTHOUGH WINDS BOTH AHEAD OF AND BEHIND THE FRONT COULD APPROACH 20 KNOTS SOUTHEAST OF CAPE FEAR WHERE SEA SURFACE TEMPERATURES ARE CURRENTLY HIGHEST. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH/REK SHORT TERM...JDW LONG TERM...TRA AVIATION...BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
650 AM EDT SAT MAY 10 2014 .SYNOPSIS...AS A COLD FRONT MOVES TOWARD THE REGION FROM THE NORTHWEST...AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE REGION THIS AFTERNOON AND EVENING. THE COLD FRONT WEAKENS AS IT APPROACHES THE CAROLINAS LATE TONIGHT AND EARLY SUNDAY. THE FRONT MOVES BACK NORTH BY MONDAY AS HIGH PRESSURE BUILDS IN FROM THE EAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 310 AM SATURDAY... THE LATEST SURFACE ANALYSIS SHOWED THE WESTERN END OF HIGH PRESSURE OVER CENTRAL NORTH CAROLINA WITH A WARM FRONT TO OUR NORTHEAST AND A COLD FRONT MOVING GRADUALLY SOUTHEAST ACROSS THE GREAT LAKES. FOR TODAY...AS THE FRONT HEADS TOWARD THE MID-ATLANTIC...BOTH THE NAM AND THE GFS MOVE A MODEST MID-LEVEL SHORTWAVE THROUGH CENTRAL NORTH CAROLINA DURING THE AFTERNOON AND EVENING HOURS. ALONG WITH THE MID- LEVEL WAVE IS AN INCREASE IN MID- AND UPPER-LEVEL WINDS...WITH THE GFS FORECASTING THE RIGHT ENTRANCE REGION OF A 75KT 300MB JETLET AND A 55KT 500MB JETLET MOVING ACROSS THE AREA INTO SOUTHERN VIRGINIA DURING THE AFTERNOON AND EARLY EVENING. UPPER DIVERGENCE ALSO INCREASES SLIGHTLY WITH THE APPROACH AND PASSAGE OF THE SHORTWAVE AND JETLETS...WITH MODEST 850MB THETA-E RIDGING IN PLACE THROUGH ABOUT 18Z. AFTER ABOUT 18Z...FORECAST CONFIDENCE IN THE DETAILS DECREASES SOME. MOS GUIDANCE SURFACE DEW POINTS ARE FORECAST TO REMAIN HIGH...IN GENERAL AROUND 60F...WHILE BOTH THE HRRR AND PARTICULARLY THE RAP MARKEDLY DIMINISH SURFACE DEW POINTS THIS AFTERNOON...THE LATTER WELL INTO THE 40S OR BELOW ESPECIALLY OVER THE SOUTHEAST PART OF CENTRAL NORTH CAROLINA. WHILE THIS MAY BE OVERDONE...THE GFS DOES SHOW A LARGE DECREASE IN 850MB THETA-E VALUES THIS AFTERNOON...SUCH THAT THERE IS AN 850MB THETA-E MINIMUM BISECTING CENTRAL NORTH CAROLINA BY 00Z. LAPSE RATES STEEPEN ESPECIALLY BETWEEN 850MB AND 500MB THIS AFTERNOON...BUT THE GFS ONLY FORECASTS SUCH LAPSE RATES TO ABOUT WHAT THEY WERE SATURDAY WHILE THE NAM IS NOTICEABLY MORE UNSTABLE. CONVECTIVE-ALLOWING MODELS SUGGEST THE BEST CHANCES FOR PRECIPITATION THIS AFTERNOON IS IN THE REGIME OF BETTER 850MB CONVERGENCE AND UPPER-LEVEL DIVERGENCE OVER THE WESTERN PIEDMONT ABOUT THE TIME OF INITIAL SHORTWAVE AND JETLET APPROACH...WITH LESSER CHANCES PARTICULARLY FROM U.S. 1 AND EAST. THIS FORECAST WILL GRADUATE POPS SIMILARLY...HIGH CHANCE OVER THE WESTERN PIEDMONT AND SLIGHT CHANCE TO LOW CHANCE ALONG AND EAST OF U.S. 1. IN TERMS OF THE POTENTIAL FOR SEVERE WEATHER...850MB WINDS DO INCREASE THIS AFTERNOON TO NEAR 40KT...AND IF THE LOW-LEVELS DO MIX MORE THAN EXPECTED...THEN AN ISOLATED NEAR-SEVERE OR SEVERE GUST IS POSSIBLE IN THE STRONGEST ECHOES. ON SATURDAY...EVEN MODEST SHOWERS WERE APPARENTLY RESULTING IN SOME WIND GUSTS NEAR 40 MPH. IN THE HWO WILL LIKELY MENTION THE POTENTIAL FOR A STRONG STORM WITH A WIND GUST TO 50 MPH AS THE BEST TEMPERATURE RISE AND INSTABILITY SHOULD LIE FARTHER EAST WHERE THE CHANCES FOR DEEP CONVECTION IS LESS. OVERNIGHT...THE SURFACE FRONT WEAKENS AS IT APPROACHES FROM THE NORTH. PRECIPITABLE WATER VALUES DIMINISH LATE...AND WILL HOLD ONTO THE POTENTIAL FOR A SLIGHT CHANCE OR AN ISOLATED SHOWER UNTIL LATE AT NIGHT...AHEAD OF THE FRONT. HIGHS TODAY...LOWER 80S FAR NORTHWEST TO UPPER 80S FAR SOUTHEAST...WITH WIND GUSTS AROUND 25 MPH AT TIMES FROM LATE MORNING THROUGH THE AFTERNOON...POSSIBLY TO AROUND 30 MPH DESPITE THE CLOUDS TOWARD THE TRIAD. OVERNIGHT LOWS AROUND 60 IN THE NORTHWEST PIEDMONT TO THE MID 60S TOWARD KFAY AND KCTZ. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 310 AM SATURDAY... A WEAK SURFACE FRONT MAY BE OVER OR NEAR THE AREA...BUT THIS BOUNDARY SHOULD HAVE LIMITED LOW-LEVEL CONVERGENCE ASSOCIATED WITH IT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS APPEAR CAPPED TO DEEP CONVECTION...AND WHILE THE GFS DOES SHOW A FEW HUNDREDTHS INCH OF PRECIPITATION MAINLY OVER THE COASTAL PLAIN SUNDAY AFTERNOON NEAR THE WEAK SURFACE BOUNDARY...MID-LEVEL FEATURES CURRENTLY SEEM TO STAY SOUTH OF THE AREA AND SHEAR IS VERY WEAK. IF A SHOWER DOES OCCUR...CURRENTLY IT IS ANTICIPATED TO BE HIGHLY ISOLATED. PRECIPITABLE WATER VALUES OVERALL ARE ONLY NEAR AN INCH TOWARD THE VIRGINIA BORDER AND THE NORTHWEST PIEDMONT...TO NEAR 1.25 INCHES TOWARD THE SANDHILLS AND SOUTHERN COASTAL PLAIN...STILL LESS THAN VALUES EXPECTED THIS AFTERNOON. WILL SHOW A DRY FORECAST SUNDAY AND SUNDAY NIGHT WITH DIMINISHING CLOUDS IN THE MORNING ESPECIALLY SOUTHEAST OF THE TRIANGLE...PARTLY TO MOSTLY SUNNY ELSEWHERE. HIGHS IN THE MID TO UPPER 80S WITH OVERNIGHT LOWS IN THE LOWER TO MID 60S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 310 AM SATURDAY... MONDAY THROUGH TUESDAY NIGHT: RIDGING ALOFT AND A BERMUDA HIGH OFF THE COAST WILL DOMINATE THIS PERIOD...RESULTING IN WARM MOIST RETURN FLOW INTO THE AREA. THE INCREASING TEMPS AND MOISTURE WILL RESULT IN MARGINAL INSTABILITY...AND WITH WEAK SHEAR OVER THE AREA...THERE WILL CONTINUE TO BE THE CHANCE FOR DIURNAL SHOWERS AND STORMS TO DEVELOP...ALTHOUGH THE CHANCE OF SEVERE STORMS CONTINUES TO BE LOW AT THIS TIME. OTHERWISE...EXPECT MAINLY DRY CONDITIONS. HIGHS IN THE MID 80S TO AROUND 90 DEGREES AND LOWS IN THE MID 60S. WEDNESDAY THROUGH FRIDAY: THERE CONTINUES TO BE A LOT OF UNCERTAINTY FOR THIS PART OF THE FORECAST...AS THE GFS (FASTER) AND ECMWF (SLOWER) CONTINUE TO DIFFER IN TIMING BY APPROX 24 HOURS OR SO... BOTH HAVING SLOWED DOWN SOME OVER THE LAST COUPLE OF MODEL RUNS. WILL CONTINUE TO LEAN MORE TOWARD THE SLOWER ECMWF PROGRESSION OF THIS SYSTEM...WITH CONFIDENCE REMAINING LOW. REGARDLESS...EXPECT INCREASING CHANCES OF SHOWERS AND STORMS THROUGH THE PERIOD...WITH THE BEST CHANCES FOR RAIN AND STRONGEST STORMS BEING THURSDAY AFT/EVE. THE SHEAR AND INSTABILITY WILL BE BEST ALONG THE FRONT... AND WITH THE BETTER FORCING DURING THIS TIME...MAY MAKE MENTION OF SOME POSSIBLE STRONG STORMS MID TO LATE WEEK IN THE HWO. WILL BE CLOSELY MONITORING THE EVOLUTION OF THIS SYSTEM AS IT APPROACHES IN HOPES OF NARROWING DOWN TIMING AND INTENSITY...AND HOPEFULLY INCREASING CONFIDENCE. EXPECT PRECIP CHANCES AND TEMPERATURES TO DECREASE BEHIND THE FRONT. THOUGH THEY WILL DEPEND ON THE TIMING OF THE FRONT AND THUS ARE LIKELY TO CHANGE OVER THE NEXT SEVERAL DAYS...GENERALLY EXPECT TEMPERATURES TO DECREASE DURING THIS PERIOD. FOR NOW EXPECT HIGHS GENERALLY IN THE MID TO UPPER 80S WEDNESDAY... DECREASING INTO THE MID TO UPPER 70S BY FRIDAY. LOWS IN THE MID 60S WEDNESDAY NIGHT...DECREASING INTO THE LOW TO MID 50S BY THE END OF THE WEEK. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 650 AM SATURDAY... VFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE 12Z VALID TAF PERIOD OUTSIDE OF ANY SHOWER OR THUNDERSTORM...AND A FEW AREAS OF EARLY MORNING LOW CLOUDS TOWARD KFAY AS NOTED BY THE SURFACE OBSERVATIONS AROUND 11Z. OUTSIDE OF A VERY ISOLATED SHOWER THIS MORNING THROUGHOUT CENTRAL NORTH CAROLINA...THE BETTER CHANCE OF A SHOWER OR THUNDERSTORM THIS AFTERNOON APPEARS TO BE ALONG AND WEST OF U.S. 1...OR AT THE KRDU AND PARTICULARLY THE TRIAD TAF SITES. THE LOW-LEVEL WIND FIELD INCREASES SUCH THAT ANY SHOWER OR THUNDERSTORM COULD PRODUCE A GUSTY WIND...AND HAVE MENTIONED THIS POSSIBILITY... FOR NOW TO 35KT...AT THE KINT AND KGSO TAF SITES. ANY SHOWERS THIS EVENING SHOULD BECOME ISOLATED AND WINDS WILL DIMINISH FROM THE SOUTH TO SOUTHWEST. BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS SHOULD BE THE RULE FOR THE REST OF THE WEEKEND. THR PROBABILITY OF LATE NIGHT AND EARLY MORNING LOW CLOUDS GRADUALLY INCREASES...CURRENTLY FIRST TOWARD THE TRIAD BY TUESDAY...AND THEN ACROSS CENTRAL NORTH CAROLINA BY WEDNESDAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS AND THEIR ASSOCIATED SUB-VFR CONDITIONS INCREASE AGAIN OVER CENTRAL NORTH CAROLINA BY WEDNESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF LONG TERM...KCP AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT SAT MAY 10 2014 .SYNOPSIS...AS A COLD FRONT MOVES TOWARD THE REGION FROM THE NORTHWEST...AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE REGION THIS AFTERNOON AND EVENING. THE COLD FRONT WEAKENS AS IT APPROACHES THE CAROLINAS LATE TONIGHT AND EARLY SUNDAY. THE FRONT MOVES BACK NORTH BY MONDAY AS HIGH PRESSURE BUILDS IN FROM THE EAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 310 AM SATURDAY... THE LATEST SURFACE ANALYSIS SHOWED THE WESTERN END OF HIGH PRESSURE OVER CENTRAL NORTH CAROLINA WITH A WARM FRONT TO OUR NORTHEAST AND A COLD FRONT MOVING GRADUALLY SOUTHEAST ACROSS THE GREAT LAKES. FOR TODAY...AS THE FRONT HEADS TOWARD THE MID-ATLANTIC...BOTH THE NAM AND THE GFS MOVE A MODEST MID-LEVEL SHORTWAVE THROUGH CENTRAL NORTH CAROLINA DURING THE AFTERNOON AND EVENING HOURS. ALONG WITH THE MID- LEVEL WAVE IS AN INCREASE IN MID- AND UPPER-LEVEL WINDS...WITH THE GFS FORECASTING THE RIGHT ENTRANCE REGION OF A 75KT 300MB JETLET AND A 55KT 500MB JETLET MOVING ACROSS THE AREA INTO SOUTHERN VIRGINIA DURING THE AFTERNOON AND EARLY EVENING. UPPER DIVERGENCE ALSO INCREASES SLIGHTLY WITH THE APPROACH AND PASSAGE OF THE SHORTWAVE AND JETLETS...WITH MODEST 850MB THETA-E RIDGING IN PLACE THROUGH ABOUT 18Z. AFTER ABOUT 18Z...FORECAST CONFIDENCE IN THE DETAILS DECREASES SOME. MOS GUIDANCE SURFACE DEW POINTS ARE FORECAST TO REMAIN HIGH...IN GENERAL AROUND 60F...WHILE BOTH THE HRRR AND PARTICULARLY THE RAP MARKEDLY DIMINISH SURFACE DEW POINTS THIS AFTERNOON...THE LATTER WELL INTO THE 40S OR BELOW ESPECIALLY OVER THE SOUTHEAST PART OF CENTRAL NORTH CAROLINA. WHILE THIS MAY BE OVERDONE...THE GFS DOES SHOW A LARGE DECREASE IN 850MB THETA-E VALUES THIS AFTERNOON...SUCH THAT THERE IS AN 850MB THETA-E MINIMUM BISECTING CENTRAL NORTH CAROLINA BY 00Z. LAPSE RATES STEEPEN ESPECIALLY BETWEEN 850MB AND 500MB THIS AFTERNOON...BUT THE GFS ONLY FORECASTS SUCH LAPSE RATES TO ABOUT WHAT THEY WERE SATURDAY WHILE THE NAM IS NOTICEABLY MORE UNSTABLE. CONVECTIVE-ALLOWING MODELS SUGGEST THE BEST CHANCES FOR PRECIPITATION THIS AFTERNOON IS IN THE REGIME OF BETTER 850MB CONVERGENCE AND UPPER-LEVEL DIVERGENCE OVER THE WESTERN PIEDMONT ABOUT THE TIME OF INITIAL SHORTWAVE AND JETLET APPROACH...WITH LESSER CHANCES PARTICULARLY FROM U.S. 1 AND EAST. THIS FORECAST WILL GRADUATE POPS SIMILARLY...HIGH CHANCE OVER THE WESTERN PIEDMONT AND SLIGHT CHANCE TO LOW CHANCE ALONG AND EAST OF U.S. 1. IN TERMS OF THE POTENTIAL FOR SEVERE WEATHER...850MB WINDS DO INCREASE THIS AFTERNOON TO NEAR 40KT...AND IF THE LOW-LEVELS DO MIX MORE THAN EXPECTED...THEN AN ISOLATED NEAR-SEVERE OR SEVERE GUST IS POSSIBLE IN THE STRONGEST ECHOES. ON SATURDAY...EVEN MODEST SHOWERS WERE APPARENTLY RESULTING IN SOME WIND GUSTS NEAR 40 MPH. IN THE HWO WILL LIKELY MENTION THE POTENTIAL FOR A STRONG STORM WITH A WIND GUST TO 50 MPH AS THE BEST TEMPERATURE RISE AND INSTABILITY SHOULD LIE FARTHER EAST WHERE THE CHANCES FOR DEEP CONVECTION IS LESS. OVERNIGHT...THE SURFACE FRONT WEAKENS AS IT APPROACHES FROM THE NORTH. PRECIPITABLE WATER VALUES DIMINISH LATE...AND WILL HOLD ONTO THE POTENTIAL FOR A SLIGHT CHANCE OR AN ISOLATED SHOWER UNTIL LATE AT NIGHT...AHEAD OF THE FRONT. HIGHS TODAY...LOWER 80S FAR NORTHWEST TO UPPER 80S FAR SOUTHEAST...WITH WIND GUSTS AROUND 25 MPH AT TIMES FROM LATE MORNING THROUGH THE AFTERNOON...POSSIBLY TO AROUND 30 MPH DESPITE THE CLOUDS TOWARD THE TRIAD. OVERNIGHT LOWS AROUND 60 IN THE NORTHWEST PIEDMONT TO THE MID 60S TOWARD KFAY AND KCTZ. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 310 AM SATURDAY... A WEAK SURFACE FRONT MAY BE OVER OR NEAR THE AREA...BUT THIS BOUNDARY SHOULD HAVE LIMITED LOW-LEVEL CONVERGENCE ASSOCIATED WITH IT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS APPEAR CAPPED TO DEEP CONVECTION...AND WHILE THE GFS DOES SHOW A FEW HUNDREDTHS INCH OF PRECIPITATION MAINLY OVER THE COASTAL PLAIN SUNDAY AFTERNOON NEAR THE WEAK SURFACE BOUNDARY...MID-LEVEL FEATURES CURRENTLY SEEM TO STAY SOUTH OF THE AREA AND SHEAR IS VERY WEAK. IF A SHOWER DOES OCCUR...CURRENTLY IT IS ANTICIPATED TO BE HIGHLY ISOLATED. PRECIPITABLE WATER VALUES OVERALL ARE ONLY NEAR AN INCH TOWARD THE VIRGINIA BORDER AND THE NORTHWEST PIEDMONT...TO NEAR 1.25 INCHES TOWARD THE SANDHILLS AND SOUTHERN COASTAL PLAIN...STILL LESS THAN VALUES EXPECTED THIS AFTERNOON. WILL SHOW A DRY FORECAST SUNDAY AND SUNDAY NIGHT WITH DIMINISHING CLOUDS IN THE MORNING ESPECIALLY SOUTHEAST OF THE TRIANGLE...PARTLY TO MOSTLY SUNNY ELSEWHERE. HIGHS IN THE MID TO UPPER 80S WITH OVERNIGHT LOWS IN THE LOWER TO MID 60S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 310 AM SATURDAY... MONDAY THROUGH TUESDAY NIGHT: RIDGING ALOFT AND A BERMUDA HIGH OFF THE COAST WILL DOMINATE THIS PERIOD...RESULTING IN WARM MOIST RETURN FLOW INTO THE AREA. THE INCREASING TEMPS AND MOISTURE WILL RESULT IN MARGINAL INSTABILITY...AND WITH WEAK SHEAR OVER THE AREA...THERE WILL CONTINUE TO BE THE CHANCE FOR DIURNAL SHOWERS AND STORMS TO DEVELOP...ALTHOUGH THE CHANCE OF SEVERE STORMS CONTINUES TO BE LOW AT THIS TIME. OTHERWISE...EXPECT MAINLY DRY CONDITIONS. HIGHS IN THE MID 80S TO AROUND 90 DEGREES AND LOWS IN THE MID 60S. WEDNESDAY THROUGH FRIDAY: THERE CONTINUES TO BE A LOT OF UNCERTAINTY FOR THIS PART OF THE FORECAST...AS THE GFS (FASTER) AND ECMWF (SLOWER) CONTINUE TO DIFFER IN TIMING BY APPROX 24 HOURS OR SO... BOTH HAVING SLOWED DOWN SOME OVER THE LAST COUPLE OF MODEL RUNS. WILL CONTINUE TO LEAN MORE TOWARD THE SLOWER ECMWF PROGRESSION OF THIS SYSTEM...WITH CONFIDENCE REMAINING LOW. REGARDLESS...EXPECT INCREASING CHANCES OF SHOWERS AND STORMS THROUGH THE PERIOD...WITH THE BEST CHANCES FOR RAIN AND STRONGEST STORMS BEING THURSDAY AFT/EVE. THE SHEAR AND INSTABILITY WILL BE BEST ALONG THE FRONT... AND WITH THE BETTER FORCING DURING THIS TIME...MAY MAKE MENTION OF SOME POSSIBLE STRONG STORMS MID TO LATE WEEK IN THE HWO. WILL BE CLOSELY MONITORING THE EVOLUTION OF THIS SYSTEM AS IT APPROACHES IN HOPES OF NARROWING DOWN TIMING AND INTENSITY...AND HOPEFULLY INCREASING CONFIDENCE. EXPECT PRECIP CHANCES AND TEMPERATURES TO DECREASE BEHIND THE FRONT. THOUGH THEY WILL DEPEND ON THE TIMING OF THE FRONT AND THUS ARE LIKELY TO CHANGE OVER THE NEXT SEVERAL DAYS...GENERALLY EXPECT TEMPERATURES TO DECREASE DURING THIS PERIOD. FOR NOW EXPECT HIGHS GENERALLY IN THE MID TO UPPER 80S WEDNESDAY... DECREASING INTO THE MID TO UPPER 70S BY FRIDAY. LOWS IN THE MID 60S WEDNESDAY NIGHT...DECREASING INTO THE LOW TO MID 50S BY THE END OF THE WEEK. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 200 AM SATURDAY... VFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE 06Z VALID TAF PERIOD OUTSIDE OF ANY SHOWER OR THUNDERSTORM. OUTSIDE OF AN ISOLATED SHOWER EARLY THIS MORNING THROUGHOUT CENTRAL NORTH CAROLINA...THE BETTER CHANCE OF A SHOWER OR THUNDERSTORM FROM LATE MORNING THROUGH THE AFTERNOON APPEARS TO BE ALONG AND WEST OF U.S. 1...OR AT THE KRDU AND PARTICULARLY THE TRIAD TAF SITES. THE LOW-LEVEL WIND FIELD INCREASES SUCH THAT ANY SHOWER OR THUNDERSTORM COULD PRODUCE A GUSTY WIND...AND HAVE MENTIONED THIS POSSIBILITY...FOR NOW TO 35KT...AT THE KINT AND KGSO TAF SITES. ANY SHOWERS THIS EVENING SHOULD BE ISOLATED AND WINDS DIMINISH FROM THE SOUTH TO SOUTHWEST. BEYOND THE 06Z VALID TAF PERIOD...VFR CONDITIONS SHOULD BE THE RULE FOR THE REST OF THE WEEKEND. THR PROBABILITY OF LATE NIGHT AND EARLY MORNING LOW CLOUDS GRADUALLY INCREASES...CURRENTLY FIRST TOWARD THE TRIAD BY TUESDAY...AND THEN ACROSS CENTRAL NORTH CAROLINA BY WEDNESDAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS AND THEIR ASSOCIATED SUB-VFR CONDITIONS INCREASE AGAIN OVER CENTRAL NORTH CAROLINA BY WEDNESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF LONG TERM...KCP AVIATION...DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
407 PM CDT SAT MAY 10 2014 .UPDATE... ISSUED AT 350 PM CDT SAT MAY 10 2014 ADDED THIS UPDATE FOR SCATTERED TO ISOLATED THUNDERSTORMS NORTHWEST REMAINDER OF THIS AFTERNOON. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 233 PM CDT SAT MAY 10 2014 THE MAIN FORECAST ISSUES IN THE SHORT TERM PERIOD ARE PRECIPITATION TRENDS AND AMOUNTS TONIGHT THROUGH SUNDAY. IN THE NEAR TERM...SHOWERS ARE MOST WIDESPREAD ACROSS THE JAMES RIVER VALLEY...THEN STRETCHING WEST ALONG THE I-94 CORRIDOR INTO THE SOUTHWEST COUNTIES. THE MODEL CONSENSUS...INCLUDING THE HIGH RESOLUTION HRRR AND WRF...INDICATE THE FOCUS OF THE HEAVIER RAIN WILL SHIFT INTO THE NORTHWEST AND NORTH CENTRAL COUNTIES LATER TONIGHT INTO SUNDAY MORNING. LINGERING SHOWERS ARE POSSIBLE ACROSS THE EAST SUNDAY AFTERNOON. ELEVATED INSTABILITY FAVORS ISOLATED LATE AFTERNOON/EVENING THUNDERSTORMS MAINLY EAST OF BISMARCK INTO THE JAMES RIVER VALLEY...BUT NO SEVERE WEATHER IS EXPECTED. FOR SUNDAY...EXPECT A CHILLY AND RAW DAY...WITH HIGHS IN THE UPPER 40S TO UPPER 50S...ABOUT 10-15 DEGREES BELOW NORMAL. A NORTHWEST WIND WILL BE SUSTAINED AT 20 TO 25 MPH AND MAY FLIRT WITH ADVISORY CRITERIA ACROSS THE FAR SOUTHWEST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 233 PM CDT SAT MAY 10 2014 AN SEMI-ACTIVE AND COOL WEATHER PATTERN WILL BE THE MAIN STORY THROUGH THE LONG TERM FORECAST PERIOD. UPPER LEVEL TROUGH OVER THE ROCKIES WILL MOVE SLOWLY EAST INTO THE CENTRAL CONUS SUNDAY NIGHT INTO MONDAY...THEN OFF TO OUR EAST TUESDAY FOLLOWED BY A QUASI-ACTIVE NORTHWEST FLOW PATTERN FOR THE REST OF THE WORK WEEK. FOR SUNDAY NIGHT-MONDAY...SUBSIDENCE ACROSS THE WESTERN HALF OF THE STATE WILL DRY THINGS OUT WITH LINGERING MOISTURE EAST ALONG THE UPPER TROUGH. WITH THE TROUGH SLOW TO MOVE EAST...DIURNALLY DRIVEN SHOWERS WILL BE POSSIBLE BOTH MONDAY AND TUESDAY. MAY BE COLD ENOUGH DURING THE OVERNIGHT/MORNING PERIODS FOR A RAIN/SNOW MIX SOME LOCATIONS. NORTHWEST FLOW WED-FRI WITH POSSIBLE EMBEDDED WAVES AND THE UPPER JET ALOFT CONTINUING THE THREAT FOR PERIODS OF LIGHT PRECIPITATION. TEMPERATURES COOL (HIGHS 40S/50S AND LOWS 30S) THROUGH MID WEEK...WITH A MODERATION IN TEMPERATURES TOWARDS NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 350 PM CDT SAT MAY 10 2014 SURFACE LOW PRESSURE ACROSS SOUTH CENTRAL NORTH DAKOTA WILL LIFT EAST NORTHEAST THROUGH TODAY. THE LOW WILL SPREAD SHOWERS ACROSS WESTERN AND NORTHERN NORTH DAKOTA THIS AFTERNOON AND TONIGHT. HAZARDS TO AVIATION SCATTERED TO ISOLATED THUNDERSTORMS FROM KJMS- KMOT THROUGH 06Z...AND LOW VFR BECOMING MVFR AFTER 02Z...THEN LOWERING TO IFR CEILINGS AFTER 06Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA LONG TERM...NH AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
233 PM CDT SAT MAY 10 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 233 PM CDT SAT MAY 10 2014 THE MAIN FORECAST ISSUES IN THE SHORT TERM PERIOD ARE PRECIPITATION TRENDS AND AMOUNTS TONIGHT THROUGH SUNDAY. IN THE NEAR TERM...SHOWERS ARE MOST WIDESPREAD ACROSS THE JAMES RIVER VALLEY...THEN STRETCHING WEST ALONG THE I-94 CORRIDOR INTO THE SOUTHWEST COUNTIES. THE MODEL CONSENSUS...INCLUDING THE HIGH RESOLUTION HRRR AND WRF...INDICATE THE FOCUS OF THE HEAVIER RAIN WILL SHIFT INTO THE NORTHWEST AND NORTH CENTRAL COUNTIES LATER TONIGHT INTO SUNDAY MORNING. LINGERING SHOWERS ARE POSSIBLE ACROSS THE EAST SUNDAY AFTERNOON. ELEVATED INSTABILITY FAVORS ISOLATED LATE AFTERNOON/EVENING THUNDERSTORMS MAINLY EAST OF BISMARCK INTO THE JAMES RIVER VALLEY...BUT NO SEVERE WEATHER IS EXPECTED. FOR SUNDAY...EXPECT A CHILLY AND RAW DAY...WITH HIGHS IN THE UPPER 40S TO UPPER 50S...ABOUT 10-15 DEGREES BELOW NORMAL. A NORTHWEST WIND WILL BE SUSTAINED AT 20 TO 25 MPH AND MAY FLIRT WITH ADVISORY CRITERIA ACROSS THE FAR SOUTHWEST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 233 PM CDT SAT MAY 10 2014 AN SEMI-ACTIVE AND COOL WEATHER PATTERN WILL BE THE MAIN STORY THROUGH THE LONG TERM FORECAST PERIOD. UPPER LEVEL TROUGH OVER THE ROCKIES WILL MOVE SLOWLY EAST INTO THE CENTRAL CONUS SUNDAY NIGHT INTO MONDAY...THEN OFF TO OUR EAST TUESDAY FOLLOWED BY A QUASI-ACTIVE NORTHWEST FLOW PATTERN FOR THE REST OF THE WORK WEEK. FOR SUNDAY NIGHT-MONDAY...SUBSIDENCE ACROSS THE WESTERN HALF OF THE STATE WILL DRY THINGS OUT WITH LINGERING MOISTURE EAST ALONG THE UPPER TROUGH. WITH THE TROUGH SLOW TO MOVE EAST...DIURNALLY DRIVEN SHOWERS WILL BE POSSIBLE BOTH MONDAY AND TUESDAY. MAY BE COLD ENOUGH DURING THE OVERNIGHT/MORNING PERIODS FOR A RAIN/SNOW MIX SOME LOCATIONS. NORTHWEST FLOW WED-FRI WITH POSSIBLE EMBEDDED WAVES AND THE UPPER JET ALOFT CONTINUING THE THREAT FOR PERIODS OF LIGHT PRECIPITATION. TEMPERATURES COOL (HIGHS 40S/50S AND LOWS 30S) THROUGH MID WEEK...WITH A MODERATION IN TEMPERATURES TOWARDS NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 110 PM CDT SAT MAY 10 2014 CONFIDENCE IS INCREASING ON COVERAGE OF SHOWERS DURING THE AFTERNOON AND TONIGHT...AS WELL AS MVFR CEILINGS AND VISIBILITIES IN SHOWERS AND LIGHT FOG. THESE CONDITIONS ARE EXPECTED TO DEVELOP THIS AFTERNOON AT KDIK/KBIS/KISN...THEN KMOT/KJMS LATER TONIGHT. PERIODS OF IFR CEILINGS ALSO POSSIBLE. WINDS WILL TRANSITION TO N/NW TONIGHT FOLLOWING THE PASSAGE OF A SURFACE LOW. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM/AVIATION...RP KINNEY LONG TERM...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
141 PM CDT SAT MAY 10 2014 .UPDATE... ISSUED AT 110 PM CDT SAT MAY 10 2014 EARLY AFTERNOON UPDATE FOR MORE ADJUSTMENT TO POPS AND TEMPERATURE TRENDS. THE MAIN CHANGE FOR TEMPS WAS LOWERING THE HIGHS ACROSS THE SOUTHWEST IN SHOWERS AND CLOUDS. ELEVATED INSTABILITY WILL BE CONFINED MAINLY TO THE SOUTHEAST...WHERE AN AFTERNOON THUNDERSTORM IS POSSIBLE. UPDATE ISSUED AT 947 AM CDT SAT MAY 10 2014 MORNING UPDATE FOR MINOR ADJUSTMENTS TO POPS TODAY. SCATTERED SHOWERS CONTINUE TO INCREASE IN COVERAGE ACROSS THE SOUTH CENTRAL...WHILE BROADER RAIN COVERAGE WILL HOLD OFF UNTIL THIS AFTERNOON IN THE WEST. POINTS SOUTH AND EAST OF BISMARCK ARE FAVORED FOR ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING...WITH NO SEVERE WEATHER EXPECTED. UPDATE ISSUED AT 634 AM CDT SAT MAY 10 2014 WATER VAPOR IMAGERY SHOWS A SHORTWAVE PIVOTING NORTH OVER WESTERN NORTH DAKOTA THIS MORNING. THIS FEATURE HAS GENERATED AN AREA OF RAIN SHOWERS ROTATING NORTH OVER SOUTHWESTERN NORTH DAKOTA. THE LATEST HRRR PROGS THIS ACTIVITY TO CONTINUE TO ROTATE NORTH OVER WESTERN NORTH DAKOTA THROUGH THE DAY...WITH INCREASING INSTABILITY DEVELOPING OVER THE SOUTHERN JAMES RIVER BASIN THIS AFTERNOON. THIS INSTABILITY WILL ALLOW FOR SHOWERS AND POSSIBLE THUNDERSTORMS TO DEVELOP EAST OF HIGHWAY 83 THIS AFTERNOON. HOWEVER...WEAK DEEP LAYER SHEAR WILL PRECLUDE ANY SEVERE DEVELOPMENT. ONLY MADE MINOR MODIFICATIONS TO THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. OTHERWISE...THE CURRENT FORECAST IS ON TRACK. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 354 AM CDT SAT MAY 10 2014 FOCUS IN THE SHORT TERM WILL BE ON THE ONSET OF PRECIPITATION TONIGHT AND CHANCES FOR THUNDERSTORMS TOMORROW AFTERNOON AND NIGHT. LATEST RADAR REFLECTIVITIES STILL SHOW PRECIPITATION JUST ACROSS THE BORDER IN EASTERN MONTANA AND NORTHWEST SOUTH DAKOTA. NEARLY ALL MODELS BROUGHT RAIN SHOWERS IN TO EARLY TONIGHT AND THUS HAVE CONTINUOUSLY BACKED OFF POPS IN THE VERY SHORT TERM THROUGH THE NIGHT. THAT SAID SHOWERS ARE BEGINNING TO FILL IN OVER WESTERN SOUTH DAKOTA AND THE LATEST MODEL CONSENSUS ON SHOWERS MOVING IN FROM SOUTH SOUTHWEST TO NORTH NORTHEAST IS GOOD IN THE EARLY MORNING HOURS THROUGH THE AFTERNOON AND EVENING. THERE MAY BE AN OPPORTUNITY FOR CONVECTION IN THE SOUTH CENTRAL NEAR THE SURFACE LOW AND ON THE BACK EDGE OF PRECIPITATION SHIELD IN THE AFTERNOON INTO THE EVENING. NOT EXPECTING ANY SEVERE STORMS IN BUT EMBEDDED THUNDER CAN NOT BE RULED OUT YET. BEYOND 00 UTC SUNDAY EMBEDDED THUNDER MAY PROGRESS AS FAR NORTH AS THE INTERNATIONAL BORDER WHILE ALSO SLIGHT CHANCES FOR STRAY THUNDERSTORMS WILL ALSO BE POSSIBLE FURTHER SOUTH IN THE JAMES RIVER VALLEY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 354 AM CDT SAT MAY 10 2014 THE MEDIUM RANGE MODELS ARE IN A LITTLE BETTER AGREEMENT WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY. HOWEVER...MODEL SOLUTIONS DIVERGE MONDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...UNCERTAINTY ABOUNDS REGARDING THE FORECAST DURING THE WORK WEEK. THE MAIN WEATHER DRIVER WILL BE THE POSITION OF AN UPPER LOW PROGGED TO AFFECT THE NORTHERN PLAINS SUNDAY-TUESDAY. THE 00Z GFS/ECMWF/GEM PROG THE LOW TO SET UP OVER SOUTHERN SASKATCHEWAN SUNDAY. THE WESTERN AND SOUTHERN COUNTIES ARE FORECAST TO GET DRY SLOTTED WITH SLIGHT CHANCE POPS INDICATED. BY MONDAY...THE 00Z GFS PROGS THE LOW TO DIP INTO NORTH CENTRAL NORTH DAKOTA WHEREAS THE 00Z GEM/ECMWF PROG THE LOW TO BECOME AN OPEN WAVE OVER SOUTHEASTERN SASKATCHEWAN/WESTERN NORTH DAKOTA. THE 00Z GFS DRY SLOTS NORTH DAKOTA WHEREAS THE 00Z ECMWF/GEM PAINT CHANCE POPS OVER EASTERN NORTH DAKOTA. FOR THE SAKE OF CONSISTENCY...WILL CONTINUE TO FOLLOW THE ECMWF/GEM SOLUTIONS FOR THIS PERIOD AND INDICATE CHANCE POPS ALONG AND EAST OF HIGHWAY 83. BY TUESDAY...THE GEM/GFS/ECMWF PROG THE LOW/OPEN WAVE TO SHIFT EAST INTO MINNESOTA...WITH NORTHWESTERLY FLOW ALOFT DEVELOPING OVER THE STATE. THIS SYNOPTIC REGIME IS FORECAST TO CONTINUE THROUGH WEDNESDAY. EMBEDDED SHORTWAVES IN THE NORTHWESTERLY FLOW ALOFT SHOULD PROVIDE AT LEAST A SLIGHT CHANCE OF RAIN SHOWERS THROUGH WEDNESDAY. BY THURSDAY...SYNOPTIC SUBSIDENCE IS PROGGED TO OVERSPREAD THE STATE AHEAD OF A SUBTLE PACIFIC RIDGE. THIS SHOULD LEAD TO MAINLY DRY CONDITIONS WITH HIGHS POSSIBLY IN THE 60S AGAIN BY FRIDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 110 PM CDT SAT MAY 10 2014 CONFIDENCE IS INCREASING ON COVERAGE OF SHOWERS DURING THE AFTERNOON AND TONIGHT...AS WELL AS MVFR CEILINGS AND VISIBILITIES IN SHOWERS AND LIGHT FOG. THESE CONDITIONS ARE EXPECTED TO DEVELOP THIS AFTERNOON AT KDIK/KBIS/KISN...THEN KMOT/KJMS LATER TONIGHT. PERIODS OF IFR CEILINGS ALSO POSSIBLE. WINDS WILL TRANSITION TO N/NW TONIGHT FOLLOWING THE PASSAGE OF A SURFACE LOW. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM...MM LONG TERM...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1004 AM CDT SAT MAY 10 2014 .UPDATE... ISSUED AT 947 AM CDT SAT MAY 10 2014 MORNING UPDATE FOR MINOR ADJUSTMENTS TO POPS TODAY. SCATTERED SHOWERS CONTINUE TO INCREASE IN COVERAGE ACROSS THE SOUTH CENTRAL...WHILE BROADER RAIN COVERAGE WILL HOLD OFF UNTIL THIS AFTERNOON IN THE WEST. POINTS SOUTH AND EAST OF BISMARCK ARE FAVORED FOR ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING...WITH NO SEVERE WEATHER EXPECTED. UPDATE ISSUED AT 634 AM CDT SAT MAY 10 2014 WATER VAPOR IMAGERY SHOWS A SHORTWAVE PIVOTING NORTH OVER WESTERN NORTH DAKOTA THIS MORNING. THIS FEATURE HAS GENERATED AN AREA OF RAIN SHOWERS ROTATING NORTH OVER SOUTHWESTERN NORTH DAKOTA. THE LATEST HRRR PROGS THIS ACTIVITY TO CONTINUE TO ROTATE NORTH OVER WESTERN NORTH DAKOTA THROUGH THE DAY...WITH INCREASING INSTABILITY DEVELOPING OVER THE SOUTHERN JAMES RIVER BASIN THIS AFTERNOON. THIS INSTABILITY WILL ALLOW FOR SHOWERS AND POSSIBLE THUNDERSTORMS TO DEVELOP EAST OF HIGHWAY 83 THIS AFTERNOON. HOWEVER...WEAK DEEP LAYER SHEAR WILL PRECLUDE ANY SEVERE DEVELOPMENT. ONLY MADE MINOR MODIFICATIONS TO THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. OTHERWISE...THE CURRENT FORECAST IS ON TRACK. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 354 AM CDT SAT MAY 10 2014 FOCUS IN THE SHORT TERM WILL BE ON THE ONSET OF PRECIPITATION TONIGHT AND CHANCES FOR THUNDERSTORMS TOMORROW AFTERNOON AND NIGHT. LATEST RADAR REFLECTIVITIES STILL SHOW PRECIPITATION JUST ACROSS THE BORDER IN EASTERN MONTANA AND NORTHWEST SOUTH DAKOTA. NEARLY ALL MODELS BROUGHT RAIN SHOWERS IN TO EARLY TONIGHT AND THUS HAVE CONTINUOUSLY BACKED OFF POPS IN THE VERY SHORT TERM THROUGH THE NIGHT. THAT SAID SHOWERS ARE BEGINNING TO FILL IN OVER WESTERN SOUTH DAKOTA AND THE LATEST MODEL CONSENSUS ON SHOWERS MOVING IN FROM SOUTH SOUTHWEST TO NORTH NORTHEAST IS GOOD IN THE EARLY MORNING HOURS THROUGH THE AFTERNOON AND EVENING. THERE MAY BE AN OPPORTUNITY FOR CONVECTION IN THE SOUTH CENTRAL NEAR THE SURFACE LOW AND ON THE BACK EDGE OF PRECIPITATION SHIELD IN THE AFTERNOON INTO THE EVENING. NOT EXPECTING ANY SEVERE STORMS IN BUT EMBEDDED THUNDER CAN NOT BE RULED OUT YET. BEYOND 00 UTC SUNDAY EMBEDDED THUNDER MAY PROGRESS AS FAR NORTH AS THE INTERNATIONAL BORDER WHILE ALSO SLIGHT CHANCES FOR STRAY THUNDERSTORMS WILL ALSO BE POSSIBLE FURTHER SOUTH IN THE JAMES RIVER VALLEY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 354 AM CDT SAT MAY 10 2014 THE MEDIUM RANGE MODELS ARE IN A LITTLE BETTER AGREEMENT WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY. HOWEVER...MODEL SOLUTIONS DIVERGE MONDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...UNCERTAINTY ABOUNDS REGARDING THE FORECAST DURING THE WORK WEEK. THE MAIN WEATHER DRIVER WILL BE THE POSITION OF AN UPPER LOW PROGGED TO AFFECT THE NORTHERN PLAINS SUNDAY-TUESDAY. THE 00Z GFS/ECMWF/GEM PROG THE LOW TO SET UP OVER SOUTHERN SASKATCHEWAN SUNDAY. THE WESTERN AND SOUTHERN COUNTIES ARE FORECAST TO GET DRY SLOTTED WITH SLIGHT CHANCE POPS INDICATED. BY MONDAY...THE 00Z GFS PROGS THE LOW TO DIP INTO NORTH CENTRAL NORTH DAKOTA WHEREAS THE 00Z GEM/ECMWF PROG THE LOW TO BECOME AN OPEN WAVE OVER SOUTHEASTERN SASKATCHEWAN/WESTERN NORTH DAKOTA. THE 00Z GFS DRY SLOTS NORTH DAKOTA WHEREAS THE 00Z ECMWF/GEM PAINT CHANCE POPS OVER EASTERN NORTH DAKOTA. FOR THE SAKE OF CONSISTENCY...WILL CONTINUE TO FOLLOW THE ECMWF/GEM SOLUTIONS FOR THIS PERIOD AND INDICATE CHANCE POPS ALONG AND EAST OF HIGHWAY 83. BY TUESDAY...THE GEM/GFS/ECMWF PROG THE LOW/OPEN WAVE TO SHIFT EAST INTO MINNESOTA...WITH NORTHWESTERLY FLOW ALOFT DEVELOPING OVER THE STATE. THIS SYNOPTIC REGIME IS FORECAST TO CONTINUE THROUGH WEDNESDAY. EMBEDDED SHORTWAVES IN THE NORTHWESTERLY FLOW ALOFT SHOULD PROVIDE AT LEAST A SLIGHT CHANCE OF RAIN SHOWERS THROUGH WEDNESDAY. BY THURSDAY...SYNOPTIC SUBSIDENCE IS PROGGED TO OVERSPREAD THE STATE AHEAD OF A SUBTLE PACIFIC RIDGE. THIS SHOULD LEAD TO MAINLY DRY CONDITIONS WITH HIGHS POSSIBLY IN THE 60S AGAIN BY FRIDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 947 AM CDT SAT MAY 10 2014 EXPECTING MVFR TO LOW VFR CEILINGS IN SHOWERS THIS AFTERNOON/EVENING AT KDIK/KISN/KBIS/KJMS...AND LATER TONIGHT AT KMOT. AN ISOLATED AFTERNOON/EVENING THUNDERSTORM IS NOT OUT OF THE QUESTION AT KJMS. WINDS WILL BECOME NORTHWESTERLY FROM WEST TO EAST TONIGHT AFTER THE PASSAGE OF A SURFACE LOW/TROUGH. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM...MM LONG TERM...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
634 AM CDT SAT MAY 10 2014 .UPDATE... ISSUED AT 634 AM CDT SAT MAY 10 2014 WATER VAPOR IMAGERY SHOWS A SHORTWAVE PIVOTING NORTH OVER WESTERN NORTH DAKOTA THIS MORNING. THIS FEATURE HAS GENERATED AN AREA OF RAIN SHOWERS ROTATING NORTH OVER SOUTHWESTERN NORTH DAKOTA. THE LATEST HRRR PROGS THIS ACTIVITY TO CONTINUE TO ROTATE NORTH OVER WESTERN NORTH DAKOTA THROUGH THE DAY...WITH INCREASING INSTABILITY DEVELOPING OVER THE SOUTHERN JAMES RIVER BASIN THIS AFTERNOON. THIS INSTABILITY WILL ALLOW FOR SHOWERS AND POSSIBLE THUNDERSTORMS TO DEVELOP EAST OF HIGHWAY 83 THIS AFTERNOON. HOWEVER...WEAK DEEP LAYER SHEAR WILL PRECLUDE ANY SEVERE DEVELOPMENT. ONLY MADE MINOR MODIFICATIONS TO THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. OTHERWISE...THE CURRENT FORECAST IS ON TRACK. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 354 AM CDT SAT MAY 10 2014 FOCUS IN THE SHORT TERM WILL BE ON THE ONSET OF PRECIPITATION TONIGHT AND CHANCES FOR THUNDERSTORMS TOMORROW AFTERNOON AND NIGHT. LATEST RADAR REFLECTIVITIES STILL SHOW PRECIPITATION JUST ACROSS THE BORDER IN EASTERN MONTANA AND NORTHWEST SOUTH DAKOTA. NEARLY ALL MODELS BROUGHT RAIN SHOWERS IN TO EARLY TONIGHT AND THUS HAVE CONTINUOUSLY BACKED OFF POPS IN THE VERY SHORT TERM THROUGH THE NIGHT. THAT SAID SHOWERS ARE BEGINNING TO FILL IN OVER WESTERN SOUTH DAKOTA AND THE LATEST MODEL CONSENSUS ON SHOWERS MOVING IN FROM SOUTH SOUTHWEST TO NORTH NORTHEAST IS GOOD IN THE EARLY MORNING HOURS THROUGH THE AFTERNOON AND EVENING. THERE MAY BE AN OPPORTUNITY FOR CONVECTION IN THE SOUTH CENTRAL NEAR THE SURFACE LOW AND ON THE BACK EDGE OF PRECIPITATION SHIELD IN THE AFTERNOON INTO THE EVENING. NOT EXPECTING ANY SEVERE STORMS IN BUT EMBEDDED THUNDER CAN NOT BE RULED OUT YET. BEYOND 00 UTC SUNDAY EMBEDDED THUNDER MAY PROGRESS AS FAR NORTH AS THE INTERNATIONAL BORDER WHILE ALSO SLIGHT CHANCES FOR STRAY THUNDERSTORMS WILL ALSO BE POSSIBLE FURTHER SOUTH IN THE JAMES RIVER VALLEY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 354 AM CDT SAT MAY 10 2014 THE MEDIUM RANGE MODELS ARE IN A LITTLE BETTER AGREEMENT WITH RESPECT TO THE UPPER PATTERN OVER THE CONUS SUNDAY. HOWEVER...MODEL SOLUTIONS DIVERGE MONDAY THROUGH THE REMAINDER OF THE PERIOD. THEREFORE...UNCERTAINTY ABOUNDS REGARDING THE FORECAST DURING THE WORK WEEK. THE MAIN WEATHER DRIVER WILL BE THE POSITION OF AN UPPER LOW PROGGED TO AFFECT THE NORTHERN PLAINS SUNDAY-TUESDAY. THE 00Z GFS/ECMWF/GEM PROG THE LOW TO SET UP OVER SOUTHERN SASKATCHEWAN SUNDAY. THE WESTERN AND SOUTHERN COUNTIES ARE FORECAST TO GET DRY SLOTTED WITH SLIGHT CHANCE POPS INDICATED. BY MONDAY...THE 00Z GFS PROGS THE LOW TO DIP INTO NORTH CENTRAL NORTH DAKOTA WHEREAS THE 00Z GEM/ECMWF PROG THE LOW TO BECOME AN OPEN WAVE OVER SOUTHEASTERN SASKATCHEWAN/WESTERN NORTH DAKOTA. THE 00Z GFS DRY SLOTS NORTH DAKOTA WHEREAS THE 00Z ECMWF/GEM PAINT CHANCE POPS OVER EASTERN NORTH DAKOTA. FOR THE SAKE OF CONSISTENCY...WILL CONTINUE TO FOLLOW THE ECMWF/GEM SOLUTIONS FOR THIS PERIOD AND INDICATE CHANCE POPS ALONG AND EAST OF HIGHWAY 83. BY TUESDAY...THE GEM/GFS/ECMWF PROG THE LOW/OPEN WAVE TO SHIFT EAST INTO MINNESOTA...WITH NORTHWESTERLY FLOW ALOFT DEVELOPING OVER THE STATE. THIS SYNOPTIC REGIME IS FORECAST TO CONTINUE THROUGH WEDNESDAY. EMBEDDED SHORTWAVES IN THE NORTHWESTERLY FLOW ALOFT SHOULD PROVIDE AT LEAST A SLIGHT CHANCE OF RAIN SHOWERS THROUGH WEDNESDAY. BY THURSDAY...SYNOPTIC SUBSIDENCE IS PROGGED TO OVERSPREAD THE STATE AHEAD OF A SUBTLE PACIFIC RIDGE. THIS SHOULD LEAD TO MAINLY DRY CONDITIONS WITH HIGHS POSSIBLY IN THE 60S AGAIN BY FRIDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 634 AM CDT SAT MAY 10 2014 A FRONTAL BOUNDARY SITS ACROSS EASTERN MONTANA INTO WESTERN SOUTH DAKOTA. EXPECT RAIN SHOWERS TO MOVE SOUTHWEST TO NORTHEAST ACROSS NORTH DAKOTA AS THE FRONTAL BOUNDER MOVES EAST ACROSS THE REGION. MVFR CONDITIONS ARE BEING SEEN IN SOME LOCATIONS RECEIVING RAINFALL IN EASTERN MONTANA AND WESTERN SOUTH DAKOTA EARLY THIS MORNING...THUS HAVE GONE AHEAD AND PUT MVFR CONDITIONS IN FOR KDIK...KISN...KJMS...AND KBIS AT THE TIME RAIN SHOWERS ARE EXPECTED. AT THIS TIME NOTHING LESS THAN MVFR IS EXPECTED WITH THE RAIN SHOWERS...HOWEVER CEILINGS MAY DROP TO IFR CATEGORY IN MORE MODERATE SHOWERS...ESPECIALLY AT SITES KDIK AND KISN. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...MM LONG TERM...TM AVIATION...MM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1250 AM CDT SAT MAY 10 2014 .UPDATE... ISSUED AT 1242 AM CDT SAT MAY 10 2014 UPDATE TO POPS ACROSS THE WEST AS SCATTERED SHOWER ACTIVITY REMAINS OVER EASTERN MONTANA AND FAR NORTHWEST SOUTH DAKOTA. LATEST HRRR MOVES SHOWERS INTO THE FAR SOUTHWEST AFTER 2 AM. UPDATE ISSUED AT 940 PM CDT FRI MAY 9 2014 SHOWERS TAKING A SLIGHTLY SLOWER EASTWARD TREND AS THEY BEGIN TO MOVE TO EASTERN MONTANA THIS EVENING. EXPECT SHOWERS MAINLY AFTER MIDNIGHT CDT ACROSS THE WEST. NEW NAM BRINGS A CHANCE OF SHOWERS SOUTH CENTRAL AFTER NOON SATURDAY WITH MOST OF THE PRECIP LIMITED TO THE NORTHWEST DURING THE DAY ON SATURDAY. UPDATE ISSUED AT 630 PM CDT FRI MAY 9 2014 SLOW MOVING AREA OF SHOWERS IN EASTERN MONTANA LIKELY WILL BEGIN TO MOVE INTO FAR WESTERN NORTH DAKOTA THIS EVENING...BUT A BIT SLOWER. ADJUSTED THIS TO A MORE MID EVENING TIME FRAME...WITH INITIALLY LOW POPS MOVING IN. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 255 PM CDT FRI MAY 9 2014 THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE PRECIPITATION CHANCES TONIGHT AND SATURDAY. ECMWF HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC MODELS AND WILL USE FOR PRECIPITATION DETAILS. CURRENTLY...SUNNY SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH INCREASING CLOUDS MOVING FROM CENTRAL INTO EASTERN MONTANA. TEMPERATURES ARE RANGING FROM THE MID 50S TO LOWER 60S ACROSS THE STATE. FOR TONIGHT...MODELS HAVE BEEN TRENDING A LITTLE SLOWER WITH THE INITIAL PRECIPITATION MOVING INTO WESTERN NORTH DAKOTA TONIGHT AND HAVE ADJUSTED POPS ACCORDINGLY. IN ADDITION...WITH THE SLOWER MOVEMENT...LATEST 17 UTC HRRR AND 18 UTC RAP ARE INDICATING BEST MOISTURE AND INSTABILITY NOT MAKING IT INTO WESTERN NORTH DAKOTA UNTIL AROUND MIDNIGHT...OR AFTER. BY THIS TIME THINK THE POSSIBILITY OF CONVECTION WILL BE MINIMAL SO WILL LEAVE OUT THE MENTION OF THUNDER. SATURDAY...A SPLIT UPPER LEVEL TROUGH TAKES SHAPE OVER THE WESTERN U.S. WITH LEAD SHORTWAVE ENERGY FROM THE SOUTHERN WAVE EJECTING INTO THE DAKOTAS. WITH AN ASSOCIATED SURFACE LOW LIFTING FROM SOUTH DAKOTA INTO CENTRAL NORTH DAKOTA. PRECIPITATION CHANCES WILL SPREAD SOUTHWEST TO NORTHEAST ACROSS THE CWA DURING THE DAY. THERE MAY BE A BRIEF OPPORTUNITY FOR CONVECTION NEAR THE SURFACE LOW AND ON THE BACK EDGE OF PRECIPITATION SHIELD IN THE SOUTH CENTRAL SATURDAY AFTERNOON. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 255 PM CDT FRI MAY 9 2014 AN ACTIVE AND COOL WEATHER PATTERN WILL BE THE MAIN STORY THROUGH THE LONG TERM FORECAST PERIOD. UPPER LOW/TROUGH OVER THE PACIFIC NORTHWEST DIGS ACROSS THE WESTERN CONUS INTO SATURDAY...MOVING OVER THE ROCKIES SUNDAY. 12Z MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE TROUGH LINGERING ACROSS THE NORTHERN PLAINS INTO TUESDAY...FOLLOWED BY AN ACTIVE NORTHWEST FLOW PATTERN FOR THE REST OF THE WORK WEEK. WILL MAINTAIN CHANCES FOR PRECIPITATION THROUGH MUCH OF THE PERIOD ALONG WITH CONTINUED COOL/BELOW AVERAGE TEMPERATURES. FOR SATURDAY NIGHT-SUNDAY...EMBEDDED UPPER LEVEL LOW LIFTS SLOWLY NORTH ACROSS THE DAKOTAS...PUTTING BEST PRECIP CHANCES NORTH AND WRAP AROUND MOISTURE WEST. MIX OF RAIN/SNOW POSSIBLE WEST SUNDAY MORNING AS COLDER AIR IS PULLED SOUTH FROM CANADA. SHOWERS CONTINUE EAST AND NORTH DURING THE DAY SUNDAY ALONG WITH INCREASING NORTHWESTERLY WINDS FROM WEST TO EAST BEHIND A SFC LOW. SUBSIDENCE ACROSS THE WESTERN HALF OF THE STATE SUNDAY NIGHT SHOULD DRY THINGS OUT WITH LINGERING MOISTURE EAST ALONG THE UPPER TROUGH. WITH THE TROUGH SLOW TO MOVE EAST...DIURNALLY DRIVEN SHOWERS WILL BE POSSIBLE BOTH MONDAY AND TUESDAY. MAY BE COLD ENOUGH DURING THE OVERNIGHT/MORNING PERIODS FOR A RAIN/SNOW MIX SOME LOCATIONS. NORTHWEST FLOW WED-FRI WITH POSSIBLE EMBEDDED WAVES AND THE UPPER JET ALOFT CONTINUING THE THREAT FOR PRECIPITATION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1250 AM CDT SAT MAY 10 2014 FRONTAL BOUNDARY SITS JUST WEST OF THE MONTANA DAKOTA BORDER AT 06 UTC TONIGHT. THIS BOUNDARY WILL SLOWLY PROGRESS EAST THROUGH THE 06 UTC TAF CYCLE. RAIN SHOWERS WILL ACCOMPANY THE FRONT FROM WEST TO EAST. AT THIS TIME VFR CONDITIONS ARE ANTICIPATED AT ALL SITES EXCEPT KISN...MVFR...STARTING AT 03 UTC. HOWEVER WITH THE SHOWERS MVFR CONDITIONS COULD BECOME COMMON ACROSS WESTERN AND CENTRAL NORTH DAKOTA. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MM SHORT TERM...TWH LONG TERM...NH AVIATION...MM
AREA FORECAST DISCUSSION
NWS TULSA OK
1149 PM CDT FRI MAY 9 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. AN ISOLATED SHOWER OR THUNDERSTORM COULD AFFECT THE NORTHWEST ARKANSAS TAF SITES IN THE FIRST COUPLE HOURS OF THE FORECAST PERIOD...BUT THE CHANCES ARE TOO LOW TO INCLUDE IN THE TAFS. MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD WITH GUSTY SOUTH WINDS DEVELOPING DURING THE DAY SATURDAY. THE ARKANSAS TAF SITES MAY SEE VISIBILITIES OCCASIONALLY FALL INTO THE MVFR CATEGORY IN LIGHT FOG LATE TONIGHT AND EARLY SATURDAY. && .PREV DISCUSSION... /ISSUED 843 PM CDT FRI MAY 9 2014/ ..UPDATE... DISCUSSION... MAIN UPDATE TO THE GOING FORECAST HAS BEEN TO PULL THUNDERSTORM CHANCES BACK TO THE NORTHWEST A BIT OVERNIGHT INTO PARTS OF NORTHEAST AND EAST CENTRAL OKLAHOMA AND ALSO MOST OF NORTHWEST ARKANSAS. BOTH THE HRRR AND THE LOCAL WRF FAVORING SOME THUNDERSTORM DEVELOPMENT ALONG THE DIFFUSE BOUNDARY TOWARD MIDNIGHT IN EAST CENTRAL OKLAHOMA AND NORTHWEST ARKANSAS AS THE MID LEVEL VORT MAX SWINGS ACROSS EASTERN OKLAHOMA AND INTO WESTERN ARKANSAS. SOME SEVERE POTENTIAL WOULD EXIST WITH ANY DEVELOPMENT ESPECIALLY GIVEN COLDER UPPER LEVEL TEMPS ASSOCIATED WITH THE VORT MAX. REMAINDER OF THE GOING FORECAST OKAY. PREV DISCUSSION... /ISSUED 619 PM CDT FRI MAY 9 2014/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. VISIBILITIES MAY BE REDUCED INTO THE MVFR CATEGORY AT TIMES IN LIGHT FOG LATE TONIGHT AND EARLY SATURDAY...MAINLY AT THE ARKANSAS TAF SITES. PREV DISCUSSION... /ISSUED 304 PM CDT FRI MAY 9 2014/ DISCUSSION... DIFFUSE SURFACE FRONT CONTINUES TO SLIDE VERY SLOWLY SE THIS AFTERNOON...AND ESSENTIALLY SEPARATES THE 45-60F DEWPOINTS IN NE OK AND 60+ DEWPOINTS ELSEWHERE. THERE REMAINS A SLIM CHANCE OF THUNDERSTORM DEVELOP LATER THIS AFTERNOON NEAR AND AHEAD OF THE QUASI-STATIONARY BOUNDARY...ALTHOUGH BEST CHANCES WILL LIKELY REMAIN EAST OF OUR FORECAST AREA. THE SURFACE FRONT WILL LIFT BACK N THROUGH THE AREA OVERNIGHT...AND COULD SEE SOME ELEVATED MORNING CONVECTION ACROSS PARTS OF NE OK/NW AR SATURDAY MORNING. AFTERNOON DESTABILIZATION SHOULD EVENTUALLY LEAD TO THUNDERSTORM DEVELOPMENT ALONG THE STRENGTHENING COLD FRONT OVER ERN KS SWWD TO THE TRIPLE POINT REGION OVER NWRN OK BY LATE AFTERNOON/EARLY EVENING. BULK OF CONVECTION IS EXPECTED TO REMAIN ACROSS KS THROUGH THE OVERNIGHT HOURS...ALTHOUGH COULD SEE SOME ACTIVITY ACROSS NE OK...IN ZONE OF 45-55KT LOW-LEVEL JET. UPPER SYSTEM CURRENTLY OFF THE PAC NW COAST WILL MOVE INLAND TODAY...AND EVENTUALLY CARVE OUT A LARGE-SCALE UPPER LOW ACROSS THE SWRN STATES. PERSISTENT/MOIST SWLY UPPER FLOW IS FORECAST FOR THE EARLY PART OF NEXT WEEK...AS THE UPPER LOW EJECTS OUT INTO THE PLAINS IN SEVERAL PIECES. RAIN CHANCES INCREASE BY SUNDAY NIGHT AND ESPECIALLY MONDAY/MONDAY NIGHT AS THE COLD FRONT ENTERS THE AREA. THE SWLY UPPER FLOW WILL FAVOR BOTH PRE AND POST-FRONTAL CONVECTION...WITH HEAVY RAINFALL LIKELY AT LEAST INTO TUESDAY MORNING. WILL CONTINUE TO FAVOR THE SLIGHTLY SLOWER SOLUTION OF THE ECMWF/CMC OVER THE MORE PROGRESSIVE GFS/DGEX...ALTHOUGH CONFIDENCE FALLS OFF SOME TOWARD THE MIDDLE OF THE WEEK AS THE ECMWF/CMC HANG ON TO RAINFALL WELL INTO WEDNESDAY. COOLER/DRIER WEATHER IS EXPECTED THE REMAINDER OF THE WEEK. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...05
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
113 AM EDT SAT MAY 10 2014 .SYNOPSIS... A WEAK FRONT WILL APPROACH THE CAROLINAS FROM THE WEST THIS EVENING AND MOVE OVER THE REGION AND THEN WASH OUT ON SATURDAY. IN THE FRONTS WAKE...VERY WARM SOUTHERLY FLOW WILL SPREAD BACK OVER THE REGION AND PERSIST UNTIL ANOTHER FRONT APPROACHES THE REGION BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... 0515 UTC UPDATE...SKY COVER HAS BEEN ADJUSTED BASED ON THE LATEST INFRARED SATELLITE IMAGERY. POPS HAVE BEEN ADJUSTED PER RADAR TRENDS...FAVORING A DECREASE IN THE SC PIEDMONT AND THE NC MOUNTAINS. AS 1015 PM...KGSP 88D INDICATED SEVERAL PATCHES OF LIGHT RETURNS ACROSS THE REGION. LATEST MESOSCALE ANALYSIS INDICATED WIDESPREAD CIN WITH VERY LIMITED CAPE. THE ONGOING LIGHT RAIN SHOULD GRADUALLY DECREASE THROUGH THE REST OF TONIGHT...I WILL KEEP LOW CHC TO SCHC POPS. THE HRRR INDICATES A FEW POCKETS OF SFC LOW COND PRES DEF ACROSS THE WESTERN NC MTNS AND I-77 CORRDIOR BY DAYBREAK. IT IS POSSIBLE THAT PATCHY FOG COULD DEVELOP OVER WET GROUND. AS OF 750 PM...A LINE OF SHOWERS AND THUNDERSTORMS WAS RUNNING FROM THE UPPER SAVANNAH RIVER VALLEY NE INTO THE NC FOOTHILLS...MOVING EAST AT 20 MPH. AT THIS RATE...THE LINE WOULD REACH KAND AT 0025 Z...KGMU 0035Z...AND KGSP AROUND 1Z. I WILL UPDATE THE FORECAST TO ADJUST TIMING. AS OF 535 PM...TCLT AND KGSP RADARS INDICATE A CLUSTER OF THUNDERSTORM SOUTH OF THE CLT METRO AREA AND A LINE OF THUNDERSTORMS ARRIVING OVER EXTREME NE GA. THE STORMS ACROSS THE PIEDMONT HAVE A HISTORY OF STRONG GUSTY WINDS WITH SMALL HAIL. THE THREAT OF GUSTY WINDS SHOULD REMAIN AS DCAPE VALUES BORDER ON 1000 J/KG. IN ADDITION...TORRENTIAL DOWNPOURS SHOULD RESULT AS THE CLUSTER TRACK NE ACROSS CLT. THE LINE TO THE WEST SHOULD SWEEP EAST OVER THE NEXT THREE HOURS. I WILL MAKE CHANGES TO MOST FORECAST FIELDS TO ALIGN WITH LATEST OBS AND THINKING. AS OF 230 PM...THE LATEST HIGH-RES MODEL RUNS ARE FINALLY STARTING TO CATCH UP WITH THE DEVELOPING CONVECTION ACRS THE ERN UPSTATE AND THE NC PIEDMONT (WHERE THEY EARLIER SHOWED LITTLE ACTIVITY) THIS AFTN. I HAVE BUMPED UP POP TO CHC IN THE ERN ZONES WHERE IT USED TO BE DRY OR ONLY SLGT CHC. THERE IS STILL ONLY 500-1000 J/KG OF SBCAPE PER THE LAPS ANALYSIS...AND SHEAR IS WEEK. SO EXPECT MAINLY SHWRS AND A FEW GARDEN VARIETY TSTMS. WITH THAT SAID...THE SPC MESOANALYSIS PAGE SHOWS DCAPE OF 1000-1200 J/KG ACRS THE ERN 1/3RD OF THE CWFA. SO EVEN SHWRS MAY PRODUCE SOME GUSTY WINDS. STILL THINK SEVERE THREAT IS LOW...GIVEN THE LOW CAPE AND SHEAR. TO THE WEST...THE EXTENSIVE CLOUDS ARE KEEPING THINGS CAPPED...WITH JUST SPOTTY LIGHT SHWRS ACRS THE NC MTNS. LATER THIS AFTN INTO THIS EVENING...SHWRS SHUD CONTINUE TO INCREASE IN COVERAGE AS DEEP LAYER MOISTURE CONTINUES TO WORK IN FROM THE WEST. BETTER INSTBY AND UPPER SUPPORT WILL ALSO SPREAD INTO THE SWRN AND CENTRAL NC MTNS...INCREASING THE THREAT FOR TSTMS. AGAIN...NOT EXPECTING MUCH SEVERE THREAT. SO THE POPS RAMPING UP TO SOLID CHC TO LIKELY INTO THIS EVENING...HIGHEST WEST...STILL LOOKS GOOD. TONIGHT...THE DEEP LAYER RH MAXIMUM AXIS WILL SPREAD INTO THE CWFA AHEAD OF A WEAKENING COLD FRONT...WHICH WILL STILL BE BACK WEST ACRS THE OH/TN VLYS. MOST OF THE GUIDANCE SEEMS TO AGREE IN GENERAL FOR A DECREASING TREND IN SHWR COVERAGE AND INTENSITY. BUT WITH PLENTY OF MOISTURE...THERE WILL PROBABLY BE AT LEAST SCATTERED LINGERING ACTIVITY THRU THE OVERNIGHT. THE CLOUDS AND MOISTURE WILL KEEP TEMPS ELEVATED ABOVE NORMAL...MAINLY IN THE 50S MTNS AND LWR-MID 60S PIEDMONT. SATURDAY...SOME OF THE CONVECTION-ALLOWING MODELS SHOW SOME SORT OF MCS ACRS THE OH VLY...TURNING TOWARD THE SW TOWARD THE NRN MTNS AROUND DAYBREAK. CONFIDENCE IS LOW...WITH NO MENTION OF THIS IN THE SPC OUTLOOKS. OTHERWISE...I ACTUALLY EXPECT A LULL IN COVERAGE DURING THE MORNING HOURS...AS INSTBY WILL BE AT ITS LOWEST. STILL...POPS ONLY DROP SLIGHTLY BASED ON THE ONGOING MOIST SW FLOW. THERE SHUD BE PLENTY OF CLOUD COVER THRU THE DAY...SO IT/S DIFFICULT TO SAY HOW MUCH INSTBY THERE WILL BE FOR REDEVELOPMENT DURING THE AFTN. WILL GO WITH HIGH-END CHC EAST TO LIKELY WEST FOR SHWRS AND SCATTERED TSTMS. PROFILES CONTINUE TO SHOW FAIRLY MODEST CAPE AND SHEAR FOR MORE ROBUST CONVECTION. SO SEVERE THREAT REMAINS LOW. THE DAY 2 CONVECTIVE OUTLOOK KEEPS OUR AREA IN GENERAL THUNDER. THE CLOUD COVER AND PRECIP SHUD KEEP TEMPS PRIMARILY IN THE 70S WEST TO LWR 80S EAST. && .SHORT TERM /TONIGHT THROUGH MONDAY/... AS OF 215 PM EDT FRI...MAJOR HEIGHT FALLS FROM THE ROCKIES TO THE PLAINS SAT NIGHT THROUGH SUNDAY WILL ALLOW A RIDGE TO GRADUALLY BUILD ACROSS THE SE LATE THIS WEEKEND. THE HIGHLY AMPLIFIED PATTERN WILL BE FULLY IN PLACE BY MON...WITH A 588 DM H5 RIDGE ENTRENCHED OVER THE SE. MAINLY A DIURNAL CONVECTIVE PATTERN IS EXPECTED UNDER THE BUILDING RIDGE SUN AND MON AFTN/EVENING...BUT PERSISTENT S TO SW LOW LEVEL FLOW COULD PROVIDE ISOLD SHRA COVERAGE IN UPSLOPE AREAS EVEN DURING THE MORNING HOURS. THE STRONGEST CONVECTION OF THE WEEKEND MAY ACTUALLY OCCUR SUNDAY AFTERNOON AND EVENING AS INSOLATION IMPROVES...BOUNDARY LAYER MOISTURE REMAINS AND SLIGHT MID LEVEL DRYING OCCURS BEFORE THE SE RIDGE REBOUNDS IN EARNEST. WILL FEATURE SOLID SCATTERED DIURNAL POPS...MAINLY OVER THE MTNS...EACH AFTN/EVENING. EXPECT MINS AND MAXES TO RUN TWO CATEGORIES OR MORE ABOVE CLIMO THROUGH THE SHORT RANGE PERIOD. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 130 PM EDT THURSDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON TUESDAY WITH UPPER RIDGING IN PLACE OVER THE SE CONUS AND DEEP UPPER TROFFING OVER THE CENTRAL AND SOUTHERN ROCKIES. OVER THE NEXT FEW DAYS...THE TROF WILL GRADUALLY MAKE ITS WAY EAST AND TOWARDS THE CAROLINAS AS THE RIDGE GETS PUSHED OFFSHORE. THE TIMING DIFFERENCES AMONG THE LONG MODELS HAVE BEEN REDUCED SINCE YESTERDAYS FCST YET THE GFS IS STILL ABOUT 12 TO 24HRS FASTER WITH THE TROFS APPROACH COMPARED TO THE GFS AND THE CANADIAN. THE OVERALL TREND OF THE FCST HAS BEEN TO LEAN MORE TOWARDS A SLOWER...ECMWF TYPE SOLUTION WHICH I WILL CONTINUE TO ADVERTISE. AT ANY RATE...THE MODELS DO AGREE THAT THE TROF SHOULD SLOW DOWN AS IT MOVES OVER THE EASTERN CONUS TOWARDS THE END OF THE MEDIUM RANGE AND STILL BE OVER THE REGION BY NEW DAY 7. AT THE SFC...THE BERMUDA HIGH WILL BE FIRMLY IN PLACE OVER THE REGION AT THE START OF THE PERIOD WITH WARM SLY LOW LVL FLOW PERSISTING OVER THE CWFA FOR MOST OF THE PERIOD. AS WITH THE UPPER LVL PATTERN...THE GFS HAS BEEN SLOWING THE APPROACH OF THE NEXT FRONTAL SYSTEM AND IS NOW MORE IN LINE WITH THE ECMWF. THE FRONT IS NOW MORE LIKELY TO MOVE INTO THE WESTERN CAROLINAS BY LATE WED/EARLY THURS AND BY EARLY FRI...THE SYSTEM SHOULD EAST OF THE CWFA. SOME DEGREE OF DRIER AND COOLER SFC RIDGING SHOULD MOVE IN BEHIND THE FROPA FOR THE REMAINDER OF THE PERIOD WITH LITTLE CHANCE FOR PRECIP. THE ECMWF AND ESPECIALLY THE CANADIAN MODELS STILL DEVELOP SOME SORT OF LOW TO OUR SE JUST OFF THE COAST OF FLORIDA BY THE END OF THE PERIOD...THE CANADIAN NOW TRYING TO SPIN UP A FULL BLOWN TROPICAL SYSTEM. AS FOR THE SENSIBLE FCST...NO SIGNIFICANT CHANGES WERE NEEDED. I DID PUSH BACK THE BEST WINDOW FOR WIDESPREAD SHOWERS AND TS BY ABOUT 6 TO 12HRS BASED ON A SLOWER FRONTAL APPROACH AND FROPA. BY 00Z FRI...ONLY A SLIGHT CHANCE LINGERS OVER THE EASTERN ZONES WITH A DRY FCST FOR THE REST OF FRI. TEMPS WILL DROP A FAIR AMOUNT ON WED AND THURS AS CLOUD COVER INCREASES AND THE FRONT PASSES THRU. ON FRI...VALUES WILL PERSIST AROUND NORMAL FOR MID MAY. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...THE LATEST MODEL GUIDANCE SUGGESTS BRIEF LOW VFR CIGS BEFORE DAWN...OTHERWISE A MID TO HIGH CIG WILL PERSIST UNTIL LATE AFTERNOON OR EARLY EVENING. MODEL GUIDANCE STILL HAS VFR VSBY AT DAYBREAK...BUT WITH RAIN SOAKED GROUND IN THE AREA...CONFIDENCE IS LOWER ON VFR. ARES JUST WEST OF KCLT HAVE A BETTER CHANCE OF FOG. SW WINDS WILL INCREASE AND BECOME GUSTY AFTER DAWN....DIMINISHING AFTER SUNSET. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED DURING THE DAY...AS A WEAKENING COLD FRONT ARRIVES...WITH THE BEST CHANCE IN THE AFTERNOON. ELSEWHERE...SOME MODEL GUIDANCE MEMBERS ARE SUPPORTIVE OF FOG RELATED VSBY RESTRICITONS TOWARD DAYBREAK...ESPECIALLY IN THE MOUNTAINS AND UPPER SAVANNAH RIVER VALLEY...AND WITH RAIN SOAKED GROUND...THE FORECAST WILL LEAN IN THAT DIRECTION. GUIDANCE SUPPORTS LOW VFR CIGS DEVELOPING BENEATH MID TO HIGH CLOUDS BY DAWN...THAT GRADUALLY BREAK UP IN THE AFTERNOON. SW WINDS WILL INCREASE AND BECOME GUSTY DURING THE DAY...THEN DIMINISH IN THE EVENING. AN APPROACHING COLD FRONT WILL SUPPORT MORE THUNDERSTORMS TODAY...WITH THE BEST CHANCE IN THE AFTERNOON DURING MAXIMUM HEATING. OUTLOOK...A WEAK COLD FRONT WILL BRING CHANCES FOR PRECIPITATION THROUGH SATURDAY NIGHT...WITH RESTRICTIONS POSSIBLE IN THUNDERSTORMS. HIGH PRESSURE RETURNS SUNDAY AND MONDAY...BUT AFTERNOON AND EVENING CONVECTION WILL BE POSSIBLE BOTH DAYS. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-05Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 95% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 95% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 95% 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...JPT NEAR TERM...ARK/JAT/NED SHORT TERM...HG LONG TERM...JPT AVIATION...JAT
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
917 PM CDT SUN MAY 11 2014 .DISCUSSION...MINOR TEMPERATURE/DEW POINT ADJUSTMENTS TO FALL IN LINE WITH CURRENT/FORECAST TEMPERATURES. SEE NO REASON AT THIS TIME TO MAKE OTHER CHANGES INLAND AREAS. && .MARINE...INCLUDED PATCHY FOG FOR THE MARINE ZONES AND SOME LOCATIONS REPORTING 2-5SM. WILL PUT A BRIEF MENTION OF THIS IN MWW. AM KEEPING SCA GOING AS THIS IS WHAT THE RUC IS SHOWING AND OTHER MODELS TOO. && .PREV DISCUSSION... /ISSUED 644 PM CDT SUN MAY 11 2014/ DISCUSSION...UPDATE FOR 00Z AVIATION DISCUSSION. AVIATION...DETERIORATING FLIGHT RULES OVERNIGHT. MVFR EARLY IN THE TAF PERIOD AT KCRP/KVCT/KALI WITH CONDITIONS QUICKLY LOWERING TO IFR BY MID EVENING...AND REMAINING AT IFR OVERNIGHT. KLRD SHOULD REMAIN VFR THRU MUCH OF THE NIGHT WITH CIGS LOWERING TO IFR BY LATE IN THE NIGHT. CIGS AT ALL TERMINALS WILL SLOWLY RISE MON MRNG WITH MVFR TO VFR RETURNING TO KLRD BY LATE MRNG...KALI BY MIDDAY...WITH KCRP/KVCT LIKELY REMAINING AT MVFR THRU MON AFTN. ISO CONVECTION MAY APPROACH KLRD BY LATE MON AFTN BUT BETTER CHANCES WILL OCCUR JUST BEYOND VALID TAF TIME FRAME...SO WILL ONLY INCLUDE VCTS FOR NOW. ELSEWHERE...CURRENTLY XPCT KCRP/KVCT/KALI TO REMAIN DRY THRU THE TAF PERIOD ASIDE FROM SOME BRIEF -DZ. MODERATE/GUSTY SE WINDS THIS EVENING WILL REMAIN BETWEEN 08-14 KTS OVERNIGHT...WITH GUSTY SE WINDS RETURNING FOR MIDDAY/AFTN HRS OF MON. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 75 88 73 76 59 / 10 30 50 70 60 VICTORIA 74 88 72 75 57 / 10 30 60 70 60 LAREDO 77 96 74 80 61 / 10 40 70 60 40 ALICE 74 91 72 77 58 / 10 30 60 70 60 ROCKPORT 75 84 73 75 62 / 10 20 40 70 60 COTULLA 75 92 71 77 57 / 10 40 70 50 40 KINGSVILLE 76 90 73 77 59 / 10 30 50 70 60 NAVY CORPUS 75 84 73 75 61 / 10 20 40 60 60 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT MONDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. && $$ GW/86...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
813 PM CDT Sun May 11 2014 .DISCUSSION... Despite the instability in place and persistent cumulus field, thunderstorms have not developed along the dryline so far this evening in the eastern TX Panhandle or Low Rolling Plains east of Lubbock. Surface convergence is weak and upper forcing is still lagging to the west over the southern Rockies. The dryline farther south is retreating to the west. The GFS looks to be the the most optimistic with convective development early tonight before 06Z in our northern and western counties. Recent HRRR and Texas Tech WRF, however, hold off with shower/thunderstorm development until 2-3 hours after Midnight across our far western counties. The Texas Tech WRF indicates possibility of isolated thunderstorm development near our northwestern border counties (Fisher and Nolan Counties) late this evening/early tonight. Given the satellite and model trends, have scaled back the PoPs early tonight with slight chance confined to the the area west of Haskell to Sweetwater before 2 AM. With the instability and deep layer shear, severe potential remains for any storms which can develop on the dryline. As large scale ascent begins to impinge on the area late tonight, could have shower/thunderstorm development across our west and northwest counties, spreading east overnight and early Monday morning. Carrying 30-40 PoPs across the area north and west of a San Angelo to Baird line late tonight. Have also adjusted sky condition to clear skies this evening based on satellite indications. Updated forecast will be out shortly. 19 && .PREV DISCUSSION... /ISSUED 650 PM CDT SUN MAY 11 2014/ AVIATION... /00Z TAFS/ Thunderstorms and MVFR ceilings are possible across West Central Texas during the next 24 hours. Forecast models indicate stratus will return to our southern terminals a couple hours after midnight. The best timing for thunderstorms will also begin after midnight and continue through tomorrow, as another cold front moves into West Central Texas. Huber PREV DISCUSSION... /ISSUED 335 PM CDT SUN MAY 11 2014/ SHORT TERM... (Tonight and Monday) A fairly complex weather forecast can be expected through the next 24 hours. Currently a dryline is located west of the area, with all of West Central Texas experiencing dewpoints in the mid 50s to lower 60s. The dryline is forecast to continue to sharpen to our west this afternoon, with an increasingly unstable atmosphere ahead of it. The main caveat is the lack of upper level forcing, and whether we are able to break the cap late this afternoon or early this evening. My current thinking is that we will see at least isolated convection along the dryline, mainly beginning this evening as better upper level forcing arrives, then moving east late this evening and early Monday morning. A strengthening low level jet should help to sustain any convection that does develop, with most convection waning by sunrise. Any storms that do develop this evening, have the potential to become strong to severe, with large hail and damaging winds being the main hazards. The main feature of interest on Monday is a cold front that will slowly move through the area. The front is forecast to move into the northern Big Country late Monday morning, then into the Concho Valley during the afternoon, with a dryline extending south across the northern Edwards Plateau. Showers and thunderstorms are forecast to develop along and ahead of the front late in the morning, then increase in coverage by mid to late afternoon. At this time, the best coverage and heaviest rainfall looks to generally east of a Cross Plains, to Eden, to Junction line, where precipitable water values of 1 to 1.5 inches are forecast. Again, a few storms could become strong to severe, with large hail and damaging winds being the main hazards. Daniels LONG TERM... (Monday night through Sunday) ..A heavy rainfall threat will exist through Monday night... A very slow moving cold front will ease across the southeast quadrant of the CWA Monday night, providing a low-level focus for convective development. Ascent will be aided by strong upper-level divergence in the right entrance region to the polar jet. Forecast precipitable water values Monday night are progged to be in the 1.4 to 1.7" range, about 2 standard deviations above the mean for this time of year. The 0-6km shear vector will be nearly parallel with the aforementioned frontal boundary, suggesting that storms may train along the baroclinic zone, enhancing the potential for locally heavy rainfall. Widespread showers and thunderstorms will result in general rainfall amounts of 1-3", with locally higher amounts, generally east of a Cross Plains to Junction line. Farther west, QPF amounts are quite a bit lighter, but a good 1/4" of rain or more is expected from Sweetwater south to Sonora. There is a threat for severe thunderstorms as well, mainly during the afternoon and evening hours before convection congeals into a multicell mess. The primary threats will be large hail and damaging winds. The cold front will be south of the area by Tuesday morning with north winds of 15-20 mph expected throughout the day. Upper-level forcing will remain present, but without the frontal forcing, it looks like precipitation will be weaker, with thunder becoming less likely. PoPs in the 20-40% range were carried southeast of an Ozona to Cross Plains line, but rainfall amounts should remain less than 1/4" on average. Temperatures will be noticeably cooler on Tuesday with highs generally in the mid 60s. The NAM is still keeping highs in the 50s across the area but this seems a bit extreme. Precip is expected to come to an end by Tuesday evening with drier air advecting into the area overnight. As winds decrease, the dry air should allow fairly strong decoupling of the boundary layer. With skies clearing, temps are expected to fall into the low/mid 40s. North to northeast winds on Wednesday will keep temps on the cool side, with highs only the 70s. We`re in store for another cool morning on Thursday with 40s once again expected across most of the area. Generally benign weather conditions are expected through the remainder of the forecast period. Dry northwesterly flow downstream of the western CONUS ridge will promote mostly clear skies. Southerly winds will resume across the area by Thursday as lee cyclogenesis ramps up. With the return flow, temps will rebound quickly into the 80s with highs expected to reach 90 degrees over the weekend. This is a potential cold front we`ll have to watch out for Friday into Saturday as a potent shortwave trough moves across the central Plains. However, the current model guidance stalls this boundary near the Red River, maintaining southerly winds across the region. Johnson FIRE WEATHER... Elevated fire weather conditions are forecast across the western Concho Valley and Crockett County Monday afternoon. Minimum relative humidity values will drop below 20 percent, but 20 foot winds will remain light. Elevated fire weather conditions will once again be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 69 80 50 66 46 / 30 40 20 10 5 San Angelo 69 84 52 65 44 / 30 30 30 10 5 Junction 72 82 57 68 47 / 10 50 70 40 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
805 PM CDT Sun May 11 2014 .DISCUSSION... Despite the instability in place and persistent cumulus field, thunderstorms have not developed along the dryline so far this evening in the eastern TX Panhandle or Low Rolling Plains east of Lubbock. Surface convergence is weak and upper forcing is still lagging to the west over the southern Rockies. The dryline farther south is retreating to the west. The GFS looks to be the the most optimistic with convective development early tonight before 06Z in our northern and western counties. Recent HRRR and Texas Tech WRF, however, hold off with shower/thunderstorm development until 2-3 hours after Midnight across our far western counties. The Texas Tech 3km WRF indicates possibility of isolated thunderstorm development near our northwestern border counties (Fisher and Nolan Counties) late this evening/early tonight. Given the satellite and model trends, have scaled back the PoPs early tonight with slight chance confined to the the area west of Haskell to Sweetwater before 2 AM. With the instability and deep layer shear, severe potential remains for any storms which can develop on the dryline. As large scale ascent begins to impinge on the area late tonight, could have shower/thunderstorm development across our west and northwest counties, spreading east overnight and early Monday morning. To varying extent, the HRRR and Texas Tech 3 Carrying 30-40 PoPs across the area north and west of a San Angelo to Baird line late tonight. Have also adjusted sky condition to clear skies this evening based on satellite indications. Updated forecast will be out shortly. 19 && .PREV DISCUSSION... /ISSUED 650 PM CDT SUN MAY 11 2014/ AVIATION... /00Z TAFS/ Thunderstorms and MVFR ceilings are possible across West Central Texas during the next 24 hours. Forecast models indicate stratus will return to our southern terminals a couple hours after midnight. The best timing for thunderstorms will also begin after midnight and continue through tomorrow, as another cold front moves into West Central Texas. Huber PREV DISCUSSION... /ISSUED 335 PM CDT SUN MAY 11 2014/ SHORT TERM... (Tonight and Monday) A fairly complex weather forecast can be expected through the next 24 hours. Currently a dryline is located west of the area, with all of West Central Texas experiencing dewpoints in the mid 50s to lower 60s. The dryline is forecast to continue to sharpen to our west this afternoon, with an increasingly unstable atmosphere ahead of it. The main caveat is the lack of upper level forcing, and whether we are able to break the cap late this afternoon or early this evening. My current thinking is that we will see at least isolated convection along the dryline, mainly beginning this evening as better upper level forcing arrives, then moving east late this evening and early Monday morning. A strengthening low level jet should help to sustain any convection that does develop, with most convection waning by sunrise. Any storms that do develop this evening, have the potential to become strong to severe, with large hail and damaging winds being the main hazards. The main feature of interest on Monday is a cold front that will slowly move through the area. The front is forecast to move into the northern Big Country late Monday morning, then into the Concho Valley during the afternoon, with a dryline extending south across the northern Edwards Plateau. Showers and thunderstorms are forecast to develop along and ahead of the front late in the morning, then increase in coverage by mid to late afternoon. At this time, the best coverage and heaviest rainfall looks to generally east of a Cross Plains, to Eden, to Junction line, where precipitable water values of 1 to 1.5 inches are forecast. Again, a few storms could become strong to severe, with large hail and damaging winds being the main hazards. Daniels LONG TERM... (Monday night through Sunday) ..A heavy rainfall threat will exist through Monday night... A very slow moving cold front will ease across the southeast quadrant of the CWA Monday night, providing a low-level focus for convective development. Ascent will be aided by strong upper-level divergence in the right entrance region to the polar jet. Forecast precipitable water values Monday night are progged to be in the 1.4 to 1.7" range, about 2 standard deviations above the mean for this time of year. The 0-6km shear vector will be nearly parallel with the aforementioned frontal boundary, suggesting that storms may train along the baroclinic zone, enhancing the potential for locally heavy rainfall. Widespread showers and thunderstorms will result in general rainfall amounts of 1-3", with locally higher amounts, generally east of a Cross Plains to Junction line. Farther west, QPF amounts are quite a bit lighter, but a good 1/4" of rain or more is expected from Sweetwater south to Sonora. There is a threat for severe thunderstorms as well, mainly during the afternoon and evening hours before convection congeals into a multicell mess. The primary threats will be large hail and damaging winds. The cold front will be south of the area by Tuesday morning with north winds of 15-20 mph expected throughout the day. Upper-level forcing will remain present, but without the frontal forcing, it looks like precipitation will be weaker, with thunder becoming less likely. PoPs in the 20-40% range were carried southeast of an Ozona to Cross Plains line, but rainfall amounts should remain less than 1/4" on average. Temperatures will be noticeably cooler on Tuesday with highs generally in the mid 60s. The NAM is still keeping highs in the 50s across the area but this seems a bit extreme. Precip is expected to come to an end by Tuesday evening with drier air advecting into the area overnight. As winds decrease, the dry air should allow fairly strong decoupling of the boundary layer. With skies clearing, temps are expected to fall into the low/mid 40s. North to northeast winds on Wednesday will keep temps on the cool side, with highs only the 70s. We`re in store for another cool morning on Thursday with 40s once again expected across most of the area. Generally benign weather conditions are expected through the remainder of the forecast period. Dry northwesterly flow downstream of the western CONUS ridge will promote mostly clear skies. Southerly winds will resume across the area by Thursday as lee cyclogenesis ramps up. With the return flow, temps will rebound quickly into the 80s with highs expected to reach 90 degrees over the weekend. This is a potential cold front we`ll have to watch out for Friday into Saturday as a potent shortwave trough moves across the central Plains. However, the current model guidance stalls this boundary near the Red River, maintaining southerly winds across the region. Johnson FIRE WEATHER... Elevated fire weather conditions are forecast across the western Concho Valley and Crockett County Monday afternoon. Minimum relative humidity values will drop below 20 percent, but 20 foot winds will remain light. Elevated fire weather conditions will once again be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 69 80 50 66 46 / 30 40 20 10 5 San Angelo 69 84 52 65 44 / 30 30 30 10 5 Junction 72 82 57 68 47 / 10 50 70 40 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1247 PM CDT SAT MAY 10 2014 .AVIATION... CONTINUED VFR WITH 15-20 KNOT SOUTHWEST WINDS BACKING SOUTH AROUND SUNSET. SLIM CHANCE THAT A FEW LOW CLOUDS COULD SNEAK INTO THE TERMINALS SUN MORNING EAST OF A DRYLINE BEFORE GUSTY SW WINDS RESUME AT THE TERMINALS AROUND 18Z. && PREV DISCUSSION... /ISSUED 440 AM CDT SAT MAY 10 2014/ SHORT TERM... LATER THIS MORNING...WINDS WILL INITIALLY INCREASE WITH LOW LEVEL JET WINDS QUICKLY MIXING DOWN TO THE SURFACE...ESPECIALLY FOR AREAS OFF THE CAPROCK. OBSERVATIONAL ANALYSIS AND RAP FORECASTS SHOW 40-50KT WINDS WITHIN 1 KFT OF THE SURFACE EARLY THIS MORNING MAXIMIZED OVER THE ROLLING PLAINS. THERE WILL THEN LIKELY BE A SLIGHT LULL IN WINDS LATE MORNING BEFORE STRONG WINDS TAKE OVER IN THE AFTERNOON. DEEP MIXING IS PROGGED TO BE APPROXIMATELY TO 600MB. HOWEVER...WINDS AROUND THIS LEVEL ARE NOT THAT NOTABLE. AN INCREASE IN THESE WINDS WILL OCCUR BY LATE IN THE AFTERNOON BUT THIS IS MORE ASSOCIATED WITH THE APPROACHING TROUGH WHICH IS CURRENTLY NEAR TROUTDALE OR. STRENGTHENING SURFACE CYCLOGENESIS OVER SOUTHEASTERN COLORADO WILL BRING THE WINDS UP DURING THE AFTERNOON. THE APPROACHING TROUGH WILL ASSIST IN A MOISTURE SURGE BACK TO THE WEST AND POSSIBLY TO THE STATE LINE ON SUNDAY MORNING. THERE MAY BE A SHOT AT SOME BRIEF LOW STRATUS ON SUNDAY MORNING COMING UP FROM THE SOUTHEAST. LONG TERM... PRIMARY FOCUS REVOLVED AROUND THE IMPACTS OF A DEEPENING UPPER LEVEL LOW PRESSURE SYSTEM ROLLING THROUGH THE FOUR-CORNERS LATE SUNDAY. SHALLOW RICH MOISTURE EARLY SUNDAY IS EXPECTED TO BE SHUNTED EAST WITH ONSET OF MIXING AND FAIRLY STRONG DOWNSLOPE WINDS...WITH A MORE DIFFUSE DRY-LINE EVENTUALLY RESIDING OVER OUR EASTERN AND SOUTHEAST BORDER AREAS LATE IN THE DAY. BACKING FLOW SUNDAY EVENING SHOULD PULL TIGHTENED DRY-LINE WEST TO NEAR THE CAP-ROCK AS AIRMASS DESTABILIZES THOUGH STILL DISAGREEMENT OVER ABILITY OF THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE ITSELF. A SHARP COLD FRONT DRIVING SOUTHWARD SUNDAY NIGHT MAY BE NEEDED TO ACTIVATE THUNDERSTORMS...ESPECIALLY AS IT NEARS THE DRY-LINE. WE MADE ONLY MINOR ADJUSTMENTS WITH THIS ATTEMPT WITH NET IMPACT TO RETAIN PREVIOUS LOW MENTION MAINLY EASTERN ZONES SUNDAY NIGHT. MUCH COOLER/COLDER AIR WILL SWEEP SOUTHWARD EARLY MONDAY WITH STIFF NORTHERLY BREEZES AS A 1030+ MB SURFACE RIDGE PRESSES SOUTHWARD FROM THE ROCKIES. THIS EVENTUALLY MAY LEAD TO A RISK FOR A LIGHT FREEZE OR FROST ACROSS OUR NORTHWEST ZONES TUESDAY AND WEDNESDAY MORNINGS. LATEST WRF/NAM THREW A BIT MORE DOUBT INTO THE EARLY WEEK FORECAST WITH A SHARPER TROUGH DIGGING THROUGH THE SOUTHERN ROCKIES TOWARDS SOUTHERN HIGH PLAINS EARLY TUESDAY ALONG WITH MORE WIDESPREAD LIGHT PRECIPITATION IN THE COLD AIR. WE HAVE EXPANDED CLOUD COVER MONDAY NIGHT INTO TUESDAY AND ALSO LOWERED TUESDAY MAXIMUMS A LITTLE MORE THOUGH NOT ENOUGH AGREEMENT AMONG VARIOUS SOLUTIONS FOR A MENTION OF PRECIPITATION TUESDAY. DRY OTHERWISE WITH SLOW WARMING LATER IN THE WEEK. SIGNIFICANT LOW LEVEL MOISTURE UNLIKELY TO RETURN THROUGH NEXT WEEK. RMCQUEEN FIRE WEATHER... THIS AFTERNOON WILL LIKELY SEE MORE WIDE SPREAD FIRE WEATHER CONCERNS BUT LOW END CRITICAL CONDITIONS ARE EXPECTED TO BE BRIEF AND INTERMITTENT. WINDS WILL INCREASE BY EARLY AFTERNOON WITH HIGHEST WINDS EXPECTED TO BE ACROSS THE WESTERN SOUTH PLAINS. WINDS AT THE 20 FOOT LEVEL WILL LIKELY BE AROUND OR JUST SLIGHTLY ABOVE 20 MPH AT THE PEAK. TEMPERATURES AROUND 10 DEGREES ABOVE SEASONAL AVERAGES AND VERY DRY AIR WILL HAVE NO ISSUE IN GENERATING RELATIVE HUMIDITY VALUES BELOW 10 PERCENT. SUNDAY CONTINUES TO LOOK LIKELY AS A CRITICAL FIRE WEATHER DAY AS SHARP UPPER LEVEL LOW PRESSURE SYSTEM DIGS INTO THE FOUR-CORNERS AREA LATE BY 00Z MONDAY. THIS SHOULD SPREAD STRONGER WIND FIELDS ACROSS THE REGION LATE SUNDAY AFTERNOON AND MAY EVEN LEAD TO EXTREMELY CRITICAL CONDITIONS AS NOTED BY THE SPC. WE CONTINUE TO HAVE QUESTION ABOUT THE TOTAL MASS AND CONTINUITY OF FUEL LOAD ESPECIALLY OVER THE HIGH PLAINS GIVEN THE ON-GOING DROUGHT THOUGH AGREE THAT EVEN MORE LIMITED FUELS WILL BE PUSHED HARD BY SUNDAYS EXPECTED 25-30 MPH WIND SPEEDS COMBINED WITH THE HOT TEMPERATURES AND VERY LOW HUMIDITY. PREVIOUS WATCH AREA STILL VALID SO NO CHANGES THIS FORECAST. RMCQUEEN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 88 54 88 42 62 / 0 0 0 10 0 TULIA 90 59 92 45 64 / 0 0 0 10 0 PLAINVIEW 92 61 93 47 66 / 0 0 0 10 0 LEVELLAND 92 57 93 48 69 / 0 0 0 10 0 LUBBOCK 95 63 95 49 70 / 0 0 0 10 0 DENVER CITY 92 55 92 50 72 / 0 0 0 10 0 BROWNFIELD 93 59 93 51 72 / 0 0 0 10 0 CHILDRESS 96 64 98 56 70 / 0 0 10 30 10 SPUR 95 65 97 57 73 / 0 0 0 20 10 ASPERMONT 98 68 98 62 75 / 0 0 10 30 10 && .LUB WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: TXZ021>025-027>031-033>037-039>042. && $$ 93
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
440 AM CDT SAT MAY 10 2014 .SHORT TERM... LATER THIS MORNING...WINDS WILL INITIALLY INCREASE WITH LOW LEVEL JET WINDS QUICKLY MIXING DOWN TO THE SURFACE...ESPECIALLY FOR AREAS OFF THE CAPROCK. OBSERVATIONAL ANALYSIS AND RAP FORECASTS SHOW 40-50KT WINDS WITHIN 1 KFT OF THE SURFACE EARLY THIS MORNING MAXIMIZED OVER THE ROLLING PLAINS. THERE WILL THEN LIKELY BE A SLIGHT LULL IN WINDS LATE MORNING BEFORE STRONG WINDS TAKE OVER IN THE AFTERNOON. DEEP MIXING IS PROGGED TO BE APPROXIMATELY TO 600MB. HOWEVER...WINDS AROUND THIS LEVEL ARE NOT THAT NOTABLE. AN INCREASE IN THESE WINDS WILL OCCUR BY LATE IN THE AFTERNOON BUT THIS IS MORE ASSOCIATED WITH THE APPROACHING TROUGH WHICH IS CURRENTLY NEAR TROUTDALE OR. STRENGTHENING SURFACE CYCLOGENESIS OVER SOUTHEASTERN COLORADO WILL BRING THE WINDS UP DURING THE AFTERNOON. THE APPROACHING TROUGH WILL ASSIST IN A MOISTURE SURGE BACK TO THE WEST AND POSSIBLY TO THE STATE LINE ON SUNDAY MORNING. THERE MAY BE A SHOT AT SOME BRIEF LOW STRATUS ON SUNDAY MORNING COMING UP FROM THE SOUTHEAST. && .LONG TERM... PRIMARY FOCUS REVOLVED AROUND THE IMPACTS OF A DEEPENING UPPER LEVEL LOW PRESSURE SYSTEM ROLLING THROUGH THE FOUR-CORNERS LATE SUNDAY. SHALLOW RICH MOISTURE EARLY SUNDAY IS EXPECTED TO BE SHUNTED EAST WITH ONSET OF MIXING AND FAIRLY STRONG DOWNSLOPE WINDS...WITH A MORE DIFFUSE DRY-LINE EVENTUALLY RESIDING OVER OUR EASTERN AND SOUTHEAST BORDER AREAS LATE IN THE DAY. BACKING FLOW SUNDAY EVENING SHOULD PULL TIGHTENED DRY-LINE WEST TO NEAR THE CAP-ROCK AS AIRMASS DESTABILIZES THOUGH STILL DISAGREEMENT OVER ABILITY OF THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE ITSELF. A SHARP COLD FRONT DRIVING SOUTHWARD SUNDAY NIGHT MAY BE NEEDED TO ACTIVATE THUNDERSTORMS...ESPECIALLY AS IT NEARS THE DRY-LINE. WE MADE ONLY MINOR ADJUSTMENTS WITH THIS ATTEMPT WITH NET IMPACT TO RETAIN PREVIOUS LOW MENTION MAINLY EASTERN ZONES SUNDAY NIGHT. MUCH COOLER/COLDER AIR WILL SWEEP SOUTHWARD EARLY MONDAY WITH STIFF NORTHERLY BREEZES AS A 1030+ MB SURFACE RIDGE PRESSES SOUTHWARD FROM THE ROCKIES. THIS EVENTUALLY MAY LEAD TO A RISK FOR A LIGHT FREEZE OR FROST ACROSS OUR NORTHWEST ZONES TUESDAY AND WEDNESDAY MORNINGS. LATEST WRF/NAM THREW A BIT MORE DOUBT INTO THE EARLY WEEK FORECAST WITH A SHARPER TROUGH DIGGING THROUGH THE SOUTHERN ROCKIES TOWARDS SOUTHERN HIGH PLAINS EARLY TUESDAY ALONG WITH MORE WIDESPREAD LIGHT PRECIPITATION IN THE COLD AIR. WE HAVE EXPANDED CLOUD COVER MONDAY NIGHT INTO TUESDAY AND ALSO LOWERED TUESDAY MAXIMUMS A LITTLE MORE THOUGH NOT ENOUGH AGREEMENT AMONG VARIOUS SOLUTIONS FOR A MENTION OF PRECIPITATION TUESDAY. DRY OTHERWISE WITH SLOW WARMING LATER IN THE WEEK. SIGNIFICANT LOW LEVEL MOISTURE UNLIKELY TO RETURN THROUGH NEXT WEEK. RMCQUEEN && .FIRE WEATHER... THIS AFTERNOON WILL LIKELY SEE MORE WIDE SPREAD FIRE WEATHER CONCERNS BUT LOW END CRITICAL CONDITIONS ARE EXPECTED TO BE BRIEF AND INTERMITTENT. WINDS WILL INCREASE BY EARLY AFTERNOON WITH HIGHEST WINDS EXPECTED TO BE ACROSS THE WESTERN SOUTH PLAINS. WINDS AT THE 20 FOOT LEVEL WILL LIKELY BE AROUND OR JUST SLIGHTLY ABOVE 20 MPH AT THE PEAK. TEMPERATURES AROUND 10 DEGREES ABOVE SEASONAL AVERAGES AND VERY DRY AIR WILL HAVE NO ISSUE IN GENERATING RELATIVE HUMIDITY VALUES BELOW 10 PERCENT. SUNDAY CONTINUES TO LOOK LIKELY AS A CRITICAL FIRE WEATHER DAY AS SHARP UPPER LEVEL LOW PRESSURE SYSTEM DIGS INTO THE FOUR-CORNERS AREA LATE BY 00Z MONDAY. THIS SHOULD SPREAD STRONGER WIND FIELDS ACROSS THE REGION LATE SUNDAY AFTERNOON AND MAY EVEN LEAD TO EXTREMELY CRITICAL CONDITIONS AS NOTED BY THE SPC. WE CONTINUE TO HAVE QUESTION ABOUT THE TOTAL MASS AND CONTINUITY OF FUEL LOAD ESPECIALLY OVER THE HIGH PLAINS GIVEN THE ON-GOING DROUGHT THOUGH AGREE THAT EVEN MORE LIMITED FUELS WILL BE PUSHED HARD BY SUNDAYS EXPECTED 25-30 MPH WIND SPEEDS COMBINED WITH THE HOT TEMPERATURES AND VERY LOW HUMIDITY. PREVIOUS WATCH AREA STILL VALID SO NO CHANGES THIS FORECAST. RMCQUEEN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 88 56 88 42 62 / 0 0 0 10 0 TULIA 90 59 91 45 64 / 0 0 0 10 0 PLAINVIEW 92 62 92 47 66 / 0 0 0 10 0 LEVELLAND 92 60 92 48 69 / 0 0 0 10 0 LUBBOCK 95 64 93 49 70 / 0 0 0 10 0 DENVER CITY 92 58 93 50 72 / 0 0 0 10 0 BROWNFIELD 93 62 93 51 72 / 0 0 10 10 0 CHILDRESS 96 69 96 56 70 / 0 0 10 20 10 SPUR 95 69 96 57 73 / 0 0 10 20 10 ASPERMONT 98 71 97 62 75 / 0 0 10 20 10 && .LUB WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: TXZ021>025-027>031-033>037-039>042. && $$ 01/05
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
938 PM CDT SUN MAY 11 2014 .UPDATE... ISSUED AT 938 PM CDT SUN MAY 11 2014 WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR POSSIBLE OVERNIGHT AND GRB ADDING A FLASH FLOOD WATCH FOR SOME OF THEIR COUNTIES IN NORTH CENTRAL WISCONSIN...HAVE DECIDED TO CHANGE OVER THE FLOOD WATCH TO A FLASH FLOOD WATCH AND EXTEND IT THROUGH 6Z TUESDAY WHEN THE COLD FRONT SHOULD BE CLEAR OF THE REGION. TIMING OF THE COMPLEX MAKING IT INTO NORTHEAST IOWA STILL LOOKS GOOD FOR AROUND MIDNIGHT NEAR THE I-35 CORRIDOR...IT IS JUST A MATTER OF HOW INTENSE IT WILL BE AS IT GETS IN. UPDATE ISSUED AT 855 PM CDT SUN MAY 11 2014 THE MAIN FOCUS WITH THE FORECAST IS WITH THE SEVERE WEATHER POTENTIAL OVERNIGHT. CURRENT SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM CENTERED NEAR OMAHA WHERE A BOWING COMPLEX HAS EMERGED FROM A LONG TRACK HP SUPERCELL THAT TRACKED ACROSS SOUTHEAST NEBRASKA THIS AFTERNOON. THE MAIN SURFACE WARM FRONT APPEARS TO EXTEND EAST FROM OMAHA ACROSS SOUTHERN IOWA WITH AN INVERTED TROUGH EXTENDING NORTH FROM THE LOW INTO SOUTHWEST MINNESOTA. ANOTHER DEW POINT GRADIENT EXISTS ALONG THE MINNESOTA/IOWA BORDER WHERE DEW POINTS GO FROM THE MID 50S IN SOUTHEAST MINNESOTA TO THE LOW 60S IN NORTHEAST IOWA. 12.00Z RAP ANALYSIS SUGGESTS THAT THERE STILL IS QUITE A BIT OF INSTABILITY AHEAD OF THIS COMPLEX RUNNING EAST ACROSS IOWA WITH 0-3KM MUCAPE AROUND 2000 J/KG FROM DES MOINES EAST AND AROUND 1000 J/KG RUNNING ALONG THE MINNESOTA/IOWA BORDER. SURFACE BASED CAPE IS STARTING TO DECREASE...BUT IS STILL FAIRLY DECENT OUT AHEAD OF THE BOW AT 2000 J/KG. SHORT TERM GUIDANCE HAS BEEN VERY CONSISTENT THIS AFTERNOON/EARLY EVENING WITH SHOWING AN INITIAL BAND OF MAINLY WEAK CONVECTION DEVELOPING ALONG THE LEADING EDGE OF THE 925-850MB MOISTURE TRANSPORT AND LIFTING NORTH THROUGH THE EVENING. THE MAIN QUESTION IS WITH WHERE THE COMPLEX IN WESTERN IOWA WILL TRACK. WITH THE 925MB JET AND MOISTURE TRANSPORT INCREASING AND LIFTING NORTH OVERNIGHT...THE SUPPORT IS THERE FOR ANY CONVECTION TO CONTINUE TO TRACK EAST-NORTHEAST. FORWARD PROPAGATING CORFIDI VECTORS AND 0-3KM SHEAR IS ALL POINTING FROM THE SOUTHWEST TO THE NORTHEAST AND THAT HAS BEEN BACKED BY THE INITIAL TRENDS WITH THE BOW. CURRENT EXTRAPOLATION AND MESO-MODELS WOULD SAY THAT THE LEADING EDGE OF THIS COMPLEX WOULD BE INTO THE CHARLES CITY IOWA AREA AROUND OR SHORTLY AFTER MIDNIGHT...TO THE MISSISSIPPI RIVER IN NE IA/SW WI AROUND 3AM...AND ON INTO SOUTH CENTRAL WISCONSIN BY 5AM. THIS LINE OF STORMS HAS ALREADY PRODUCED 80MPH WIND GUSTS AT OMAHA...BUT DO NOT EXPECT IT TO BE AT THAT STRENGTH...BUT STILL POSSIBLY SEVERE...AS IT GETS INTO THE REGION. AM CONSIDERING CHANGING THE FLOOD WATCH TO A FLASH FLOOD WATCH SINCE THERE APPEARS TO BE A CHANCE THAT THIS COMPLEX SLOWS DOWN AND PRODUCES SOME HEAVY RAINFALL OVER A SHORT PERIOD OVERNIGHT THAT IS TIED MORE TO CONVECTION THAN A LONG LIVED MODERATE RAIN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 325 PM CDT SUN MAY 11 2014 FOCUS OF THE FORECAST IS ON RAIN THROUGH TUESDAY. REGIONAL RADARS SHOW A CONVECTIVE COMPLEX HAS SURVIVED FROM THE OVERNIGHT HOURS AND CONTINUES TO TRANSLATE ACROSS SOUTHERN IOWA. THAT HAS EFFECTIVELY PINNED THE WARM FRONT WELL SOUTH OF THE AREA ALONG THE IOWA/MISSOURI BORDER. THIS HAS ALSO PINNED MOST OF THE CAPE TO THE SOUTH WITH THE 19Z MU CAPE SHOWING LESS THAN 500 J/KG ACROSS THE AREA. THE CONCERN BECOMES WHAT HAPPENS THIS EVENING AS THE COMPLEX CONTINUES TO MOVE EAST AND IF THE WARM FRONT CAN MAKE A MOVE NORTH. THE 11.17Z HRRR SUGGESTS THAT THE WARM FRONT WILL START TO PUSH NORTH THIS EVENING BUT MAY STILL BE ONLY ABOUT AS FAR NORTH AS THE INTERSTATE 80 CORRIDOR BY 03Z. THE WARM FRONT COULD THEN GET PUSHED NORTHEAST THROUGH THE REST OF THE EVENING AND NIGHT AS A STRONG SHORT WAVE TROUGH MOVES NORTHEAST ACROSS THE REGION. THE 11.12Z NAM DOES SUGGEST BETWEEN 1000-1500 J/KG OF ML CAPE WILL BE IN PLACE ALONG AND NEAR THE WARM FRONT...BUT IF THE WARM FRONT GETS PUSHED NORTHEAST...THIS CAPE MAY JUST CLIP THE SOUTHEAST PORTIONS OF THE AREA. HOWEVER...IF THIS SCENARIO DOES NOT PLAY OUT AND THE CAPE IS FARTHER WEST...THERE WILL STILL BE A SEVERE THREAT. THE 0-6KM SHEAR THIS EVENING SHOULD INCREASE TO A RANGE OF 30 TO 50 KNOTS THIS EVENING THEN TO AROUND 60 KNOTS FOR THE OVERNIGHT HOURS. THE NAM REMAINS CONSISTENT SHOWING 200-300 M2/S2 OF HELICITY OVER THE AREA IN THE 0-3KM LAYER WITH THE BULK OF THE RESIDING THE 0-1KM LAYER. SO IF THE WARM FRONT CAN GET INTO THE AREA...THERE WOULD STILL BE A THREAT FOR AN ISOLATED TORNADO...BUT CONFIDENCE ON THE POSITION OF THE WARM FRONT IS NOT VERY HIGH. CONFIDENCE IS HIGH THAT IT WILL RAIN TONIGHT. THE MODELS HAVE BEEN CONVERGING TOWARD THE SCENARIO THAT AS THE SHORT WAVE TROUGH COMES OUT OF THE CENTRAL PLAINS AND MOVES NORTHEAST OVER THE REGION TONIGHT THAT CONVECTION WILL FORM ALONG AN INVERTED TROUGH. THIS TROUGH CURRENTLY EXTENDS FROM THE SOUTHWEST KANSAS ACROSS WESTERN IOWA INTO WESTERN WISCONSIN. AS THE SHORT WAVE TROUGH COMES OUT...MODERATE PV ADVECTION IN THE 500-300 MB LAYER IS EXPECTED TO OCCUR. IN THE LOW LEVELS...THE WARM AIR ADVECTION WILL INCREASE AHEAD OF THE WAVE WITH 5 TO 7 UBAR/S OF UP GLIDE ON THE 300K ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS LEVEL RIGHT INTO THE AREA. EXPECT TO SEE THE LINE OF CONVECTION DEVELOP IN RESPONSE TO THIS WAVE FROM SOUTHERN MINNESOTA INTO KANSAS AND THEN MOVE NORTHEAST ACROSS THE AREA THROUGH THE NIGHT. ONCE THE SHORT WAVE TROUGH MOVES PAST...THE FORCING WILL SHIFT BACK TO THE WEST AGAIN AHEAD OF THE MAIN LONG WAVE TROUGH AND THE EMBEDDED SHORT WAVE TROUGH. THIS IS EXPECTED TO MAKE THE MAIN SURFACE LOW MOVE FROM KANSAS INTO MINNESOTA OR WISCONSIN DURING THE DAY MONDAY WITH THE COLD FRONT ADVANCING EAST INTO THE AREA. ANOTHER ROUND OF VERY SIMILAR ISENTROPIC UP GLIDE AND MOISTURE TRANSPORT IS EXPECTED ON THE 300K SURFACE FOR CONTINUED SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT. EVERYTHING THEN STARTS TO TRANSLATE EAST FOR MONDAY NIGHT WITH THE RAIN CHANCES ENDING FROM WEST TO EAST THROUGH TUESDAY MORNING. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 325 PM CDT SUN MAY 11 2014 WILL CARRY SOME SMALL RAIN CHANCES FOR WEDNESDAY THROUGH FRIDAY AND THEN SOME ON AND OFF CHANCES OVER THE WEEKEND. ONCE THE SYSTEM FROM EARLY IN THE WEEK MOVES PAST...THE LONG WAVE TROUGH LOOKS TO REMAIN OVER THE CENTRAL PART OF THE COUNTRY WITH A NORTHWEST FLOW FROM NORTHWEST CANADA. THIS SHOULD ALLOW SEVERAL WEAK SHORT WAVE TROUGHS TO ROTATE THROUGH THE LONG WAVE TROUGH TO SUPPORT THE RAIN CHANCES. THIS FLOW WILL ALSO HELP TO KEEP TEMPERATURES BELOW NORMAL WITH HIGHS IN THE 50S TO END THE WEEK AND THEN CREEPING BACK INTO THE 60S FOR THE WEEKEND. OVERNIGHT LOWS WILL BE IN THE 30S AND MAY HAVE TO DEAL WITH SOME FROST HEADLINES TOWARD THE END OF THE WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 638 PM CDT SUN MAY 11 2014 CONFIDENCE REMAINS HIGH THAT RAIN SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE REGION THIS EVENING AND OVERNIGHT WITH IFR CONDITIONS LIKELY WITHIN THE THUNDERSTORM CLUSTERS. THE FIRST WAVE OF SHOWERS AND STORMS ARE CURRENTLY MOVING NORTH ACROSS NORTHEAST IOWA AND SHOULD BE INTO THE RST VICINITY AROUND 1Z AND LSE VICINITY AROUND 3Z. THE MORE WIDESPREAD THUNDERSTORMS ARE EXPECTED TO COME THROUGH LATE THIS EVENING AND OVERNIGHT BEFORE TRACKING TO THE EAST BY DAYBREAK. A BREAK IS EXPECTED TO OCCUR WITH ANOTHER ROUND OF STORMS EXPECTED TOMORROW AFTERNOON. && .HYDROLOGY... ISSUED AT 325 PM CDT SUN MAY 11 2014 RAINFALL FROM THIS SYSTEM THROUGH MONDAY SHOULD AVERAGE AROUND 2 INCHES FOR MUCH OF THE FORECAST AREA WITH LOCALIZED HIGHER AMOUNTS EXPECTED. MANY OF THE RIVERS REMAIN HIGH FROM RECENT RUN OFFS AND THE LATEST FORECASTS FROM THE RFC INDICATED WITHIN BANK RISES FOR MANY OF THE TRIBUTARIES WITH RENEWED FLOODING POSSIBLE AT SOME SPOTS ALONG THE MISSISSIPPI. IF THE RAINFALL ENDS UP BEING HIGHER THAN THE QPF USED BY THE RFC...WHICH IS HIGH PROBABILITY...SOME THE TRIBUTARIES COULD ALSO GO TO FLOOD. BASED ON THIS...HAVE OPTED TO ISSUE A FLOOD WATCH FOR THE ENTIRE AREA FOR TONIGHT AND MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR WIZ017-029- 032>034-041>044-053>055-061. MN...FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR IAZ008>011-018- 019-029-030. && $$ UPDATE...HALBACH SHORT TERM...04 LONG TERM...04 AVIATION...HALBACH HYDROLOGY...04
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
936 PM CDT SUN MAY 11 2014 .UPDATE... EXPECTED LULL OCCURRING AFTER LATE AFTERNOON/EARLY EVENING STRONG/SEVERE CONVECTION. WATCHING WRN IOWA CONVECTION AS MODELS ARE TAKING THIS COMPLEX AND LIFTING IT TO THE NNE ON LOW-LEVEL JET. THE BAND OF BROKEN CONVECTION OVER SRN MN IN CONVERGENCE ZONE ON THE LEADING EDGE OF THE STRONGER 850 MB WINDS...WHICH MODELS KEEP WEST OF SRN WI FOR MOST OF THE OVERNIGHT. STILL CHANCES OF THUNDER INCREASE AFTER MIDNIGHT AS LOW-LEVEL WINDS HEEL OVER TOWARD FORECAST AREA...ESPECIALLY AFTER 09Z...THOUGH THEY DO WEAKEN. COULD SEE SOME HEAVY RAIN TOTALS IN A SHORT AMOUNT OF TIME WITH ANY OVERNIGHT CONVECTION WITH PRECIPITABLE WATER VALUES RISING FROM 1.2 TO 1.5 INCHES. WILL KEEP HIGHLIGHTED WORDING IN ZFP AND HWO THOUGH LATEST NAM AND HRRR INDICATE BEST POTENTIAL FOR HEAVIEST RAIN WILL BE NORTH AND WEST OF CWA. && .AVIATION/06Z TAFS/... WILL KEEP PREVIOUS TREND OF LOWERING CIGS WITH APPROACH OF WARM FRONT THAT EARLIER CONVECTION HAS NOW PUSHED SOUTH INTO CENTRAL IL...BUT SHOULD BEGIN A NORTHWARD TREK OVERNIGHT AS LOW PRESSURE LIFTS UP THROUGH KS AND IA. WILL SEE A CONTINUED BREAK IN PCPN UNTIL AFTER 06Z...AND POSSIBLY CLOSER TO 09Z...WHEN LOW-LEVEL JET WINDS HEEL OVER TOWARD SRN WI. THEN ANOTHER BREAK WITH ONLY A FEW SCATTERED SHOWERS UNTIL COLD FRONT PUSHES WEST TO EAST MONDAY EVENING/OVERNIGHT. HAVE A CHANCE OF SEEING SEVERE STORMS ALONG THIS LINE WITH GUSTY WINDS AND HAIL. && .PREV DISCUSSION... /ISSUED 225 PM CDT SUN MAY 11 2014/ REST OF THIS AFTERNOON AND TONIGHT - CONFIDENCE...MEDIUM SPC MESO PAGE CONTINUES TO SHOW DESTABILIZATION IN THE MID LEVELS WITH MUCAPE INCREASING. ELEVATED HAIL PRODUCING STORMS WILL MOVE TAKING SHAPE ACRS NE IA. LOW LEVELS ALSO DESTABLIZED. SSW WINDS HAVE BROUGHT 60 PLUS DEW POINT AIR INTO PARTS OF SC WI. HAIL AND HEAVY RAIN APPEAR TO BE THE MAIN THREATS DUE TO FAVORABLE MID LEVEL LAPSE RATES AND MOISTURE ADVECTION. 0-6KM SHEAR NOT THAT FAVORABLE. FOR LATER TONIGHT...UPPER TROUGH AND PRIMARY SHORTWAVE ENERGY AT THE BASE OF TROUGH WILL CONTINUE TO SHIFT EAST FROM THE ROCKIES. A LEAD SHORTWAVE PICKED UP BY THE MODELS IS EXPECTED TO REACH NW WI BY 12Z. SURFACE LOW WILL HEAD NORTHEAST AND BECOME SOMEWHAT ELONGATED FROM MN THROUGH WRN IA. WIND FLOW WILL RESPOND AND INCREASE FROM THE SOUTH. LOW LEVEL JET DOES TRANSLATE EASTWARD A BUT THOUGH PRIMARY FORCING IS WEST. HOWEVER ENOUGH MOISTURE ADVECTION AND SPEED CONVERGENCE TO SUPPORT TSRA ACRS THE CWA. HRRR SHOWING POTENTIAL MCS ARRIVING AFTER 7Z OR SO INTO WRN CWA. 12Z NAM AND 12Z GFS DO FOCUS THE STRONGEST CONVECTION CLOSER TO THE NOSE OF THE JET TO OUR WEST...HOWEVER 12Z ECMWF/12Z GEM LEAN THE JET CLOSER TO SRN WI WITH QPF PANELS RESPONDING WITH A MORE ORGANIZED CONVECTIVE COMPLEX TAKING SHAPE. GIVEN THE SHORTWAVE RIDING NORTHEAST AND PLACEMENT OF LLJ AXIS...WILL PLAY IT THAT MORE ORGANIZED CONVECTION RETURNS LATER TONIGHT AFTER A BREAK BETWEEN THE AFTN/EARLY EVE STORMS. MONDAY - CONFIDENCE...MEDIUM LEADING EDGE OF UPPER TROUGH DYNAMICS PUSH INTO WRN IA AND WRN MN. STRONG SOUTHWEST UPPER FLOW ACRS SRN WI. WARM SECTOR WILL BE WELL ENTRENCHED ACRS SRN WI. MODELS IN GENERAL GREEMENT IN TAKING SURFACE LOW FROM MN TOWARDS NW WI. WARM...MOIST AND UNSTABLE AIRMASS IN PLACE. THE UPPER JET WILL BE WELL TO OUR WEST THOUGH MODELS HINTING AT SOME UPPER DIVERGENCE HERE. BUFKIT SOUNDINGS SHOW DECENT MOISTURE WITH CAPES OVER 1000 J/KG. SO REAL EMPHASIS WILL BE ON THE TRIGGER. 4KM SPC WRF SHOWS GENERAL WARM SECTOR/AIRMASS DEVELOPMENT WITH MAIN FOCUS FURTHER WEST IN CLOSER PROXIMITY TO THE COLD FRONT. 925 TEMPS WILL BE AROUND 20C... SOME LAKE COOLING POSSIBLE BUT NOT EXPECTING MUCH OF AN INLAND PUSH WITH THAT...SO EXPECT HIGHS WELL INTO THE 70S WITH A FEW LOW 80S. MONDAY NIGHT...FORECAST CONFIDENCE - MEDIUM. RIGHT ENTRANCE REGION OF UPPER JET PASSES ACROSS SRN WI AS SFC CDFNT MOVES ACROSS. PWAT VALUES WILL REMAIN IN THE 1.5 INCH RANGE AHEAD OF THE FRONT WITH DEEP WARM CLOUD DEPTH AND MBE VELOCITY LESS THAN 10 KNOTS MOST OF THE NIGHT. 925-850MB MOISTURE FLUX CONVERGENCE INCREASES ONCE AGAIN BUT DOES NOT REMAIN ORIENTATED WITH THE MEAN STEERING FLOW. NEVER THE LESS...POTENTIAL FOR HEAVY RAINFALL WL CONTINUE DURING THIS PD DUE TO STRONG FORCING AND DEEP MOISTURE. TUESDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE - HIGH. SFC CDFNT WILL BE EXITING SOUTHEAST WISCONSIN EARLY TUESDAY MORNING. LINGERING SHRA IN ITS WAKE SHOULD GRADUALLY DIMINISH FROM WEST TO EAST AS COOLER...DRIER AIR SLOWLY WORKS ITS WAY ACROSS SRN WI AND LOW LEVEL FRONTOGENETICAL FORCING SLIDES OFF TO THE EAST. A QUIET AND COOL NIGHT IS EXPECTED TUESDAY NIGHT AS ANY INSTABILITY -SHRA THAT WILL HAVE FORMED UPSTREAM IN THE AREA OF STEEP LOW TO MID LEVEL LAPSE RATES SHOULD END WITH INSOLATION LOSS. ON WEDNESDAY...MOST OF THE SHORT TERM GUIDANCE HINTING AT NEW SHORT WAVE ROUNDING BASE OF LONG WAVE TROUGH OVER CENTRAL CONUS AND TAKING NORTHEAST TRACK ALONG BAROCLINIC ZONE THROUGH TN AND OH VALLEY REGION WED AND WED NGT. WL CONTINUE LOWER POPS FOR NOW WITH HIGHEST IN THE SOUTHEAST WHERE PORTIONS OF SOUTHERN WI MAY BE ON THE NORTHWEST SIDE OF THE EXPANDING PRECIP SHIELD WITH THIS SYSTEM. WEDNESDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE - MEDIUM. BROADSCALE AGREEMENT IN THE MEDIUM RANGE GUIDANCE ON COOLER AIR SETTLING INTO THE REGION AND LINGERING THROUGH THE END OF THE WEEK. THIS WILL BE DUE TO LINGERING LONG WAVE TROUGH OVER CENTRAL CONUS WHICH WILL BE SPREADING SLOWLY EWD THROUGH THE END OF THE WEEK. EWD PROGRESSION OF TROUGH WL BE SLOWED BY WESTERN ATLANTIC BLOCKING RIDGE. MID-UPPER LEVEL RIDGE AXIS EXPCD TO PERSIST OVER WI THROUGH FRI. SHORT WAVE TROUGH APPROACHING PACIFIC NW WILL FINALLY NUDGE TROF TO THE EAST OF WI FOR THE WEEKEND. HENCE THE COOLER THAN NORMAL TEMPERATURES THAT WILL HAVE SETTLED OVER SRN WI BY WED ARE EXPECTED TO LINGER INTO THE WEEKEND BEFORE GRADUALLY WARMING. 85H TEMPS WL HAVE COOLED TO AROUND 0C BY WED AND WL REMAIN A FEW DEGREES WITH 0C INTO SAT. IN ADDITION...WEAKER SHORT WAVES ROTATING AROUND PARENT LONG WAVE TROUGH MAY BRING SOME -SHRA TO SRN WI FROM WED THROUGH FRI. LAST SEVERAL RUNS OF THE ECMWF HAVE BEEN SHOWING MORE POTENT LOW PRESSURE MOVING NORTHWARD THROUGH TN/OH VALLEYS WED NGT INTO THU...WITH THE POTENTIAL FOR PORTIONS OF SRN WI ON THE NORTHWEST WIDE OF THE -RA SHIELD FROM THIS SYSTEM. CANADIAN AND GFS SHOW WEAKER RIPPLE AND ECMWF ENSEMBLE FLATTENS THIS STRONGER SYSTEM AS WELL. HENCE FOR NOW WL CONTINUE LOWER POPS FOR -SHRA WED NIGHT INTO THU. EXPECTING MORE CLOUDS AND WEAK BOUNDARY LAYER MIXING TO KEEP OVERNIGHT TEMPERATURES IN THE MIDDLE 30S TO LOWER 40S THURSDAY NIGHT AND AGAIN FRIDAY NIGHT. HOWEVER IF MORE CLEARING IS EXPECTED IN THESE PERIODS IN LATER FORECAST PERIODS...WL NEED TO CONSIDER ADDING FROST TO THE LATE NIGHT FORECASTS. AVIATION/12Z TAFS/...HRRR AND 4KM SPC WRF SHOW SOME ELEVATED STORMS INTO SRN WI THIS AFTN/EVE WHICH LOOKS RIGHT ON GIVEN TRENDS IN 88-D. LOOKING AT A BREAK A BIT LATER THIS EVE BEFORE POTENTIAL MCS ARRIVES AFTER MIDNIGHT. THREAT THIS EVE LOOKS TO BE HAIL WITH DECENT MID LEVEL LAPSE RATES. MORE DEVELOPMENT LIKELY TONIGHT AS LLJ REFOCUSES TO OUR WEST AND THE LOW TO OUR WEST STRENGTHENS. NAM/GFS KEYING ON IA/SE MN/ CNTRL/NRN WI THOUGH 12Z ECMWF/GEM AND HRRR SUGGEST STORMS FOCUSED MORE INTO SRN WI. POTENTIAL FOR MORE SHRA/TSRA ON MONDAY WITH WARM/HUMID/UNSTABLE AIRMASS THOUGH COLD FRONT STILL BACK TO OUR WEST AND NOT EXPECTED TO ARRIVE UNTIL MONDAY NIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...REM TONIGHT/MONDAY AND AVIATION/MARINE...COLLAR MONDAY NIGHT THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
855 PM CDT SUN MAY 11 2014 .UPDATE... ISSUED AT 855 PM CDT SUN MAY 11 2014 THE MAIN FOCUS WITH THE FORECAST IS WITH THE SEVERE WEATHER POTENTIAL OVERNIGHT. CURRENT SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM CENTERED NEAR OMAHA WHERE A BOWING COMPLEX HAS EMERGED FROM A LONG TRACK HP SUPERCELL THAT TRACKED ACROSS SOUTHEAST NEBRASKA THIS AFTERNOON. THE MAIN SURFACE WARM FRONT APPEARS TO EXTEND EAST FROM OMAHA ACROSS SOUTHERN IOWA WITH AN INVERTED TROUGH EXTENDING NORTH FROM THE LOW INTO SOUTHWEST MINNESOTA. ANOTHER DEW POINT GRADIENT EXISTS ALONG THE MINNESOTA/IOWA BORDER WHERE DEW POINTS GO FROM THE MID 50S IN SOUTHEAST MINNESOTA TO THE LOW 60S IN NORTHEAST IOWA. 12.00Z RAP ANALYSIS SUGGESTS THAT THERE STILL IS QUITE A BIT OF INSTABILITY AHEAD OF THIS COMPLEX RUNNING EAST ACROSS IOWA WITH 0-3KM MUCAPE AROUND 2000 J/KG FROM DES MOINES EAST AND AROUND 1000 J/KG RUNNING ALONG THE MINNESOTA/IOWA BORDER. SURFACE BASED CAPE IS STARTING TO DECREASE...BUT IS STILL FAIRLY DECENT OUT AHEAD OF THE BOW AT 2000 J/KG. SHORT TERM GUIDANCE HAS BEEN VERY CONSISTENT THIS AFTERNOON/EARLY EVENING WITH SHOWING AN INITIAL BAND OF MAINLY WEAK CONVECTION DEVELOPING ALONG THE LEADING EDGE OF THE 925-850MB MOISTURE TRANSPORT AND LIFTING NORTH THROUGH THE EVENING. THE MAIN QUESTION IS WITH WHERE THE COMPLEX IN WESTERN IOWA WILL TRACK. WITH THE 925MB JET AND MOISTURE TRANSPORT INCREASING AND LIFTING NORTH OVERNIGHT...THE SUPPORT IS THERE FOR ANY CONVECTION TO CONTINUE TO TRACK EAST-NORTHEAST. FORWARD PROPAGATING CORFIDI VECTORS AND 0-3KM SHEAR IS ALL POINTING FROM THE SOUTHWEST TO THE NORTHEAST AND THAT HAS BEEN BACKED BY THE INITIAL TRENDS WITH THE BOW. CURRENT EXTRAPOLATION AND MESO-MODELS WOULD SAY THAT THE LEADING EDGE OF THIS COMPLEX WOULD BE INTO THE CHARLES CITY IOWA AREA AROUND OR SHORTLY AFTER MIDNIGHT...TO THE MISSISSIPPI RIVER IN NE IA/SW WI AROUND 3AM...AND ON INTO SOUTH CENTRAL WISCONSIN BY 5AM. THIS LINE OF STORMS HAS ALREADY PRODUCED 80MPH WIND GUSTS AT OMAHA...BUT DO NOT EXPECT IT TO BE AT THAT STRENGTH...BUT STILL POSSIBLY SEVERE...AS IT GETS INTO THE REGION. AM CONSIDERING CHANGING THE FLOOD WATCH TO A FLASH FLOOD WATCH SINCE THERE APPEARS TO BE A CHANCE THAT THIS COMPLEX SLOWS DOWN AND PRODUCES SOME HEAVY RAINFALL OVER A SHORT PERIOD OVERNIGHT THAT IS TIED MORE TO CONVECTION THAN A LONG LIVED MODERATE RAIN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 325 PM CDT SUN MAY 11 2014 FOCUS OF THE FORECAST IS ON RAIN THROUGH TUESDAY. REGIONAL RADARS SHOW A CONVECTIVE COMPLEX HAS SURVIVED FROM THE OVERNIGHT HOURS AND CONTINUES TO TRANSLATE ACROSS SOUTHERN IOWA. THAT HAS EFFECTIVELY PINNED THE WARM FRONT WELL SOUTH OF THE AREA ALONG THE IOWA/MISSOURI BORDER. THIS HAS ALSO PINNED MOST OF THE CAPE TO THE SOUTH WITH THE 19Z MU CAPE SHOWING LESS THAN 500 J/KG ACROSS THE AREA. THE CONCERN BECOMES WHAT HAPPENS THIS EVENING AS THE COMPLEX CONTINUES TO MOVE EAST AND IF THE WARM FRONT CAN MAKE A MOVE NORTH. THE 11.17Z HRRR SUGGESTS THAT THE WARM FRONT WILL START TO PUSH NORTH THIS EVENING BUT MAY STILL BE ONLY ABOUT AS FAR NORTH AS THE INTERSTATE 80 CORRIDOR BY 03Z. THE WARM FRONT COULD THEN GET PUSHED NORTHEAST THROUGH THE REST OF THE EVENING AND NIGHT AS A STRONG SHORT WAVE TROUGH MOVES NORTHEAST ACROSS THE REGION. THE 11.12Z NAM DOES SUGGEST BETWEEN 1000-1500 J/KG OF ML CAPE WILL BE IN PLACE ALONG AND NEAR THE WARM FRONT...BUT IF THE WARM FRONT GETS PUSHED NORTHEAST...THIS CAPE MAY JUST CLIP THE SOUTHEAST PORTIONS OF THE AREA. HOWEVER...IF THIS SCENARIO DOES NOT PLAY OUT AND THE CAPE IS FARTHER WEST...THERE WILL STILL BE A SEVERE THREAT. THE 0-6KM SHEAR THIS EVENING SHOULD INCREASE TO A RANGE OF 30 TO 50 KNOTS THIS EVENING THEN TO AROUND 60 KNOTS FOR THE OVERNIGHT HOURS. THE NAM REMAINS CONSISTENT SHOWING 200-300 M2/S2 OF HELICITY OVER THE AREA IN THE 0-3KM LAYER WITH THE BULK OF THE RESIDING THE 0-1KM LAYER. SO IF THE WARM FRONT CAN GET INTO THE AREA...THERE WOULD STILL BE A THREAT FOR AN ISOLATED TORNADO...BUT CONFIDENCE ON THE POSITION OF THE WARM FRONT IS NOT VERY HIGH. CONFIDENCE IS HIGH THAT IT WILL RAIN TONIGHT. THE MODELS HAVE BEEN CONVERGING TOWARD THE SCENARIO THAT AS THE SHORT WAVE TROUGH COMES OUT OF THE CENTRAL PLAINS AND MOVES NORTHEAST OVER THE REGION TONIGHT THAT CONVECTION WILL FORM ALONG AN INVERTED TROUGH. THIS TROUGH CURRENTLY EXTENDS FROM THE SOUTHWEST KANSAS ACROSS WESTERN IOWA INTO WESTERN WISCONSIN. AS THE SHORT WAVE TROUGH COMES OUT...MODERATE PV ADVECTION IN THE 500-300 MB LAYER IS EXPECTED TO OCCUR. IN THE LOW LEVELS...THE WARM AIR ADVECTION WILL INCREASE AHEAD OF THE WAVE WITH 5 TO 7 UBAR/S OF UP GLIDE ON THE 300K ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS LEVEL RIGHT INTO THE AREA. EXPECT TO SEE THE LINE OF CONVECTION DEVELOP IN RESPONSE TO THIS WAVE FROM SOUTHERN MINNESOTA INTO KANSAS AND THEN MOVE NORTHEAST ACROSS THE AREA THROUGH THE NIGHT. ONCE THE SHORT WAVE TROUGH MOVES PAST...THE FORCING WILL SHIFT BACK TO THE WEST AGAIN AHEAD OF THE MAIN LONG WAVE TROUGH AND THE EMBEDDED SHORT WAVE TROUGH. THIS IS EXPECTED TO MAKE THE MAIN SURFACE LOW MOVE FROM KANSAS INTO MINNESOTA OR WISCONSIN DURING THE DAY MONDAY WITH THE COLD FRONT ADVANCING EAST INTO THE AREA. ANOTHER ROUND OF VERY SIMILAR ISENTROPIC UP GLIDE AND MOISTURE TRANSPORT IS EXPECTED ON THE 300K SURFACE FOR CONTINUED SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT. EVERYTHING THEN STARTS TO TRANSLATE EAST FOR MONDAY NIGHT WITH THE RAIN CHANCES ENDING FROM WEST TO EAST THROUGH TUESDAY MORNING. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 325 PM CDT SUN MAY 11 2014 WILL CARRY SOME SMALL RAIN CHANCES FOR WEDNESDAY THROUGH FRIDAY AND THEN SOME ON AND OFF CHANCES OVER THE WEEKEND. ONCE THE SYSTEM FROM EARLY IN THE WEEK MOVES PAST...THE LONG WAVE TROUGH LOOKS TO REMAIN OVER THE CENTRAL PART OF THE COUNTRY WITH A NORTHWEST FLOW FROM NORTHWEST CANADA. THIS SHOULD ALLOW SEVERAL WEAK SHORT WAVE TROUGHS TO ROTATE THROUGH THE LONG WAVE TROUGH TO SUPPORT THE RAIN CHANCES. THIS FLOW WILL ALSO HELP TO KEEP TEMPERATURES BELOW NORMAL WITH HIGHS IN THE 50S TO END THE WEEK AND THEN CREEPING BACK INTO THE 60S FOR THE WEEKEND. OVERNIGHT LOWS WILL BE IN THE 30S AND MAY HAVE TO DEAL WITH SOME FROST HEADLINES TOWARD THE END OF THE WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 638 PM CDT SUN MAY 11 2014 CONFIDENCE REMAINS HIGH THAT RAIN SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE REGION THIS EVENING AND OVERNIGHT WITH IFR CONDITIONS LIKELY WITHIN THE THUNDERSTORM CLUSTERS. THE FIRST WAVE OF SHOWERS AND STORMS ARE CURRENTLY MOVING NORTH ACROSS NORTHEAST IOWA AND SHOULD BE INTO THE RST VICINITY AROUND 1Z AND LSE VICINITY AROUND 3Z. THE MORE WIDESPREAD THUNDERSTORMS ARE EXPECTED TO COME THROUGH LATE THIS EVENING AND OVERNIGHT BEFORE TRACKING TO THE EAST BY DAYBREAK. A BREAK IS EXPECTED TO OCCUR WITH ANOTHER ROUND OF STORMS EXPECTED TOMORROW AFTERNOON. && .HYDROLOGY... ISSUED AT 325 PM CDT SUN MAY 11 2014 RAINFALL FROM THIS SYSTEM THROUGH MONDAY SHOULD AVERAGE AROUND 2 INCHES FOR MUCH OF THE FORECAST AREA WITH LOCALIZED HIGHER AMOUNTS EXPECTED. MANY OF THE RIVERS REMAIN HIGH FROM RECENT RUN OFFS AND THE LATEST FORECASTS FROM THE RFC INDICATED WITHIN BANK RISES FOR MANY OF THE TRIBUTARIES WITH RENEWED FLOODING POSSIBLE AT SOME SPOTS ALONG THE MISSISSIPPI. IF THE RAINFALL ENDS UP BEING HIGHER THAN THE QPF USED BY THE RFC...WHICH IS HIGH PROBABILITY...SOME THE TRIBUTARIES COULD ALSO GO TO FLOOD. BASED ON THIS...HAVE OPTED TO ISSUE A FLOOD WATCH FOR THE ENTIRE AREA FOR TONIGHT AND MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLOOD WATCH THROUGH MONDAY EVENING FOR WIZ017-029-032>034- 041>044-053>055-061. MN...FLOOD WATCH THROUGH MONDAY EVENING FOR MNZ079-086>088-094>096. IA...FLOOD WATCH THROUGH MONDAY EVENING FOR IAZ008>011-018-019-029- 030. && $$ UPDATE...HALBACH SHORT TERM...04 LONG TERM...04 AVIATION...HALBACH HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
638 PM CDT SUN MAY 11 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 325 PM CDT SUN MAY 11 2014 FOCUS OF THE FORECAST IS ON RAIN THROUGH TUESDAY. REGIONAL RADARS SHOW A CONVECTIVE COMPLEX HAS SURVIVED FROM THE OVERNIGHT HOURS AND CONTINUES TO TRANSLATE ACROSS SOUTHERN IOWA. THAT HAS EFFECTIVELY PINNED THE WARM FRONT WELL SOUTH OF THE AREA ALONG THE IOWA/MISSOURI BORDER. THIS HAS ALSO PINNED MOST OF THE CAPE TO THE SOUTH WITH THE 19Z MU CAPE SHOWING LESS THAN 500 J/KG ACROSS THE AREA. THE CONCERN BECOMES WHAT HAPPENS THIS EVENING AS THE COMPLEX CONTINUES TO MOVE EAST AND IF THE WARM FRONT CAN MAKE A MOVE NORTH. THE 11.17Z HRRR SUGGESTS THAT THE WARM FRONT WILL START TO PUSH NORTH THIS EVENING BUT MAY STILL BE ONLY ABOUT AS FAR NORTH AS THE INTERSTATE 80 CORRIDOR BY 03Z. THE WARM FRONT COULD THEN GET PUSHED NORTHEAST THROUGH THE REST OF THE EVENING AND NIGHT AS A STRONG SHORT WAVE TROUGH MOVES NORTHEAST ACROSS THE REGION. THE 11.12Z NAM DOES SUGGEST BETWEEN 1000-1500 J/KG OF ML CAPE WILL BE IN PLACE ALONG AND NEAR THE WARM FRONT...BUT IF THE WARM FRONT GETS PUSHED NORTHEAST...THIS CAPE MAY JUST CLIP THE SOUTHEAST PORTIONS OF THE AREA. HOWEVER...IF THIS SCENARIO DOES NOT PLAY OUT AND THE CAPE IS FARTHER WEST...THERE WILL STILL BE A SEVERE THREAT. THE 0-6KM SHEAR THIS EVENING SHOULD INCREASE TO A RANGE OF 30 TO 50 KNOTS THIS EVENING THEN TO AROUND 60 KNOTS FOR THE OVERNIGHT HOURS. THE NAM REMAINS CONSISTENT SHOWING 200-300 M2/S2 OF HELICITY OVER THE AREA IN THE 0-3KM LAYER WITH THE BULK OF THE RESIDING THE 0-1KM LAYER. SO IF THE WARM FRONT CAN GET INTO THE AREA...THERE WOULD STILL BE A THREAT FOR AN ISOLATED TORNADO...BUT CONFIDENCE ON THE POSITION OF THE WARM FRONT IS NOT VERY HIGH. CONFIDENCE IS HIGH THAT IT WILL RAIN TONIGHT. THE MODELS HAVE BEEN CONVERGING TOWARD THE SCENARIO THAT AS THE SHORT WAVE TROUGH COMES OUT OF THE CENTRAL PLAINS AND MOVES NORTHEAST OVER THE REGION TONIGHT THAT CONVECTION WILL FORM ALONG AN INVERTED TROUGH. THIS TROUGH CURRENTLY EXTENDS FROM THE SOUTHWEST KANSAS ACROSS WESTERN IOWA INTO WESTERN WISCONSIN. AS THE SHORT WAVE TROUGH COMES OUT...MODERATE PV ADVECTION IN THE 500-300 MB LAYER IS EXPECTED TO OCCUR. IN THE LOW LEVELS...THE WARM AIR ADVECTION WILL INCREASE AHEAD OF THE WAVE WITH 5 TO 7 UBAR/S OF UP GLIDE ON THE 300K ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS LEVEL RIGHT INTO THE AREA. EXPECT TO SEE THE LINE OF CONVECTION DEVELOP IN RESPONSE TO THIS WAVE FROM SOUTHERN MINNESOTA INTO KANSAS AND THEN MOVE NORTHEAST ACROSS THE AREA THROUGH THE NIGHT. ONCE THE SHORT WAVE TROUGH MOVES PAST...THE FORCING WILL SHIFT BACK TO THE WEST AGAIN AHEAD OF THE MAIN LONG WAVE TROUGH AND THE EMBEDDED SHORT WAVE TROUGH. THIS IS EXPECTED TO MAKE THE MAIN SURFACE LOW MOVE FROM KANSAS INTO MINNESOTA OR WISCONSIN DURING THE DAY MONDAY WITH THE COLD FRONT ADVANCING EAST INTO THE AREA. ANOTHER ROUND OF VERY SIMILAR ISENTROPIC UP GLIDE AND MOISTURE TRANSPORT IS EXPECTED ON THE 300K SURFACE FOR CONTINUED SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT. EVERYTHING THEN STARTS TO TRANSLATE EAST FOR MONDAY NIGHT WITH THE RAIN CHANCES ENDING FROM WEST TO EAST THROUGH TUESDAY MORNING. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 325 PM CDT SUN MAY 11 2014 WILL CARRY SOME SMALL RAIN CHANCES FOR WEDNESDAY THROUGH FRIDAY AND THEN SOME ON AND OFF CHANCES OVER THE WEEKEND. ONCE THE SYSTEM FROM EARLY IN THE WEEK MOVES PAST...THE LONG WAVE TROUGH LOOKS TO REMAIN OVER THE CENTRAL PART OF THE COUNTRY WITH A NORTHWEST FLOW FROM NORTHWEST CANADA. THIS SHOULD ALLOW SEVERAL WEAK SHORT WAVE TROUGHS TO ROTATE THROUGH THE LONG WAVE TROUGH TO SUPPORT THE RAIN CHANCES. THIS FLOW WILL ALSO HELP TO KEEP TEMPERATURES BELOW NORMAL WITH HIGHS IN THE 50S TO END THE WEEK AND THEN CREEPING BACK INTO THE 60S FOR THE WEEKEND. OVERNIGHT LOWS WILL BE IN THE 30S AND MAY HAVE TO DEAL WITH SOME FROST HEADLINES TOWARD THE END OF THE WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 638 PM CDT SUN MAY 11 2014 CONFIDENCE REMAINS HIGH THAT RAIN SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE REGION THIS EVENING AND OVERNIGHT WITH IFR CONDITIONS LIKELY WITHIN THE THUNDERSTORM CLUSTERS. THE FIRST WAVE OF SHOWERS AND STORMS ARE CURRENTLY MOVING NORTH ACROSS NORTHEAST IOWA AND SHOULD BE INTO THE RST VICINITY AROUND 1Z AND LSE VICINITY AROUND 3Z. THE MORE WIDESPREAD THUNDERSTORMS ARE EXPECTED TO COME THROUGH LATE THIS EVENING AND OVERNIGHT BEFORE TRACKING TO THE EAST BY DAYBREAK. A BREAK IS EXPECTED TO OCCUR WITH ANOTHER ROUND OF STORMS EXPECTED TOMORROW AFTERNOON. && .HYDROLOGY... ISSUED AT 325 PM CDT SUN MAY 11 2014 RAINFALL FROM THIS SYSTEM THROUGH MONDAY SHOULD AVERAGE AROUND 2 INCHES FOR MUCH OF THE FORECAST AREA WITH LOCALIZED HIGHER AMOUNTS EXPECTED. MANY OF THE RIVERS REMAIN HIGH FROM RECENT RUN OFFS AND THE LATEST FORECASTS FROM THE RFC INDICATED WITHIN BANK RISES FOR MANY OF THE TRIBUTARIES WITH RENEWED FLOODING POSSIBLE AT SOME SPOTS ALONG THE MISSISSIPPI. IF THE RAINFALL ENDS UP BEING HIGHER THAN THE QPF USED BY THE RFC...WHICH IS HIGH PROBABILITY...SOME THE TRIBUTARIES COULD ALSO GO TO FLOOD. BASED ON THIS...HAVE OPTED TO ISSUE A FLOOD WATCH FOR THE ENTIRE AREA FOR TONIGHT AND MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLOOD WATCH THROUGH MONDAY EVENING FOR WIZ017-029-032>034- 041>044-053>055-061. MN...FLOOD WATCH THROUGH MONDAY EVENING FOR MNZ079-086>088-094>096. IA...FLOOD WATCH THROUGH MONDAY EVENING FOR IAZ008>011-018-019-029- 030. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...HALBACH HYDROLOGY...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY ISSUED AT 324 PM CDT SAT MAY 10 2014 CONCERN ON PCPN CHANCES TONIGHT INTO SUNDAY. HIGH PRESSURE OVER STATE...LEADING TO DEEP MIXING AND DEW POINTS IN THE LOWER 20S IN SOME OF OUR DRIER SPOTS. MORNING SOUNDINGS MSP AND GRB SHOWING THIS DRY AIR. AREA OF CLOUDS/SHOWERS WITH SHORT WAVE HAVING HARD TIME MOVING NORTH. HRRR SHOWS THE AREA DRYING UP AS MOVES INTO SOUTHWEST WI. HAVE BACKED OFF ON CLOUDS/POPS THROUGH EARLY EVENING HOURS. SHORT WAVE TO WEAKEN AS IT LIFTS NORTH TO THE WEST OF STATE. MODELS TRENDS HAVE BEEN WEST WITH PCPN WITH LOW LEVEL FLOW FOCUSED INTO SOUTHERN MN...SHIFTING SOUTHWEST INTO WESTERN WI LATE. HAVE BACKED OFF ON EASTWARD PROGRESSION WITH POPS...THINKING BEST POPS NORTH LATE TONIGHT WITH 850 FRONT LIFTING INTO THE AREA. PCPN WITH THE LEAD WAVE EXPECTED TO EXIT THE N DURING THE MORNING...THEN EXPECT A LULL FOR THE MUCH OF THE DAY. MADE LITTLE CHANGE TO PREVIOUS FORECAST FOR TEMPS/AFTN POPS. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY ISSUED AT 324 PM CDT SAT MAY 10 2014 MAIN CONCERN WILL BE THE SYSTEM SUNDAY NIGHT INTO TUESDAY MORNING. LOW LEVEL JET IS EXPECTED TO INCREASE TO 50 TO 60 KTS SUNDAY NIGHT. MID LEVEL LAPSE RATES WERE NEAR 6 C/KM. THERE IS CONSIDERABLE CONCERN WHERE AXIS OF HEAVY RAIN WILL SET UP. BASED ON POSITION OF THE SURFACE WARM FRONT...WRF MODEL TOO FAR NORTH WHILE THE GFS IS FURTHER SOUTH COMPARED TO THE CANADIAN/ECMWF. IF GFS IS CORRECT...THE HEAVY RAIN SUNDAY NIGHT WOULD BE SOUTH OF OUR AREA AND THE WARM FRONT WILL BE NO WHERE CLOSE TO OUR FORECAST AREA AS OUTFLOW BOUNDARIES SHOULD SHOVE THE FRONT SOUTH. IF THE ECMWF/CANADIAN ARE CORRECT...OUR SOUTHERN FORECAST AREA WILL BE ON THE NORTHERN EDGE OF THE HEAVY RAIN. MAIN CONCERN FOR LATER SUNDAY NIGHT WILL BE THE POTENTIAL FOR HEAVY RAIN AND SMALL HAIL. EITHER WAY...SURFACE WARM FRONT WILL BE SOUTH OF OUR AREA ON MONDAY. ONGOING CONVECTION/OUTFLOW BOUNDARIES FROM OVERNIGHT CONVECTION THAT LINGERS INTO MONDAY MORNING WILL SLOW THE NORTHWARD PROGRESS OF THE WARM FRONT. THE SEVERE POTENTIAL REMAINS UNCERTAIN FOR THESE REASONS. IF WE DO GET SOME CLEARING ACROSS THE SOUTH ON MONDAY...SOME OF THE STORMS COULD BECOME STRONG OR SEVERE... ESPECIALLY SOUTH OF HIGHWAY 29. A SECONDARY WAVE IS EXPECTED TO MOVE ALONG THE FRONT MONDAY NIGHT INTO TUESDAY MORNING...BRINGING MORE LOCALLY HEAVY RAIN. RAINFALL TOTALS OF 1 TO 2 INCHES ARE EXPECTED ACROSS MUCH OF THE AREA...WITH LOCALLY HIGHER AMOUNTS ACROSS THE SOUTH. HIGH PRESSURE BUILDS INTO THE REGION TUESDAY NIGHT. COOL CYCLONIC FLOW EXPECTED FOR THE REMAINDER OF THE WORK WEEK...BRINGING A CHANCE FOR INSTABILITY SHOWERS WEDNESDAY THROUGH FRIDAY. THE GREATEST CONCENTRATION OF SHOWERS WILL BE DURING THE AFTERNOON AND EARLY EVENING HOURS. CAN NOT RULE OUT ISOLATED/SCATTERED SHOWERS OUTSIDE THIS PERIOD EACH DAY DUE TO WEAK DISTURBANCES MOVING WITH THE MEAN FLOW. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1201 PM CDT SAT MAY 10 2014 MAINLY VFR CONDITIONS EXPECTED THROUGHOUT THE TAF PERIOD. MODELS TRENDING WEST AND NORTH WITH PCPN TONIGHT...WHICH IN TURN HAS TO DEAL WITH RATHER DRY AIRMASS TODAY. PCPN THAT DEVELOPS TNGT SHOULD BE PRIMARY OUT OF A MIDDLE CLOUD DECK... THOUGH COULD GET SOME BRIEF MVFR CIGS WITH ANY HEAVIER SHOWERS MAINLY NORTH CENTRAL. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....TE LONG TERM......ECKBERG AVIATION.......TE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
310 PM CDT SAT MAY 10 2014 .SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT) ISSUED AT 310 PM CDT SAT MAY 10 2014 MAIN FORECAST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES THIS EVENING AND AGAIN SUN AFTERNOON/NIGHT. POTENTIAL HEAVY RAINS SUN NIGHT. 18Z DATA ANALYSIS HAD A WEAK RIDGE OF HIGH PRESSURE FROM NORTHEAST MN THRU SOUTHEAST WI. SUNNY...QUIET DAY OVER THE NORTHEAST HALF OF THE REGION. WV IMAGERY SHOWED A MORE ROBUST LOOKING SHORTWAVE LIFTING NORTHEAST ACROSS SD/NEB EARLY THIS AFTERNOON. THIS WAVE AND SOME 850-700MB MOISTURE TRANSPORT/THERMO-DYNAMIC FORCING RESPONSIBLE FOR A BROAD BAND OF SCT SHRA/ISOLATED TSRA LIFTING ACROSS NORTHERN IA/SOUTHWEST MN. PER 10.12Z KMPX SOUNDING...PLENTY OF DRY AIR ABOVE 850MB AHEAD OF THIS BAND OF SHRA/TSRA TO OVERCOME BEFORE PRECIP REACHES THE GROUND...AND MOST RAIN AMOUNTS SO FAR TODAY HAVE BEEN A TRACE TO A FEW HUNDREDTHS OF AN INCH. 10.12Z MODELS INITIALIZED WELL...BUT FOR GFS ABOUT 5F HIGH ON SFC DEW POINTS ACROSS THE SOUTH HALF OF THE UPPER MS VALLEY. SOLUTIONS CONTINUE TO OFFER A TIGHTER CONSENSUS ON THE SHORTWAVE TO LIFT ACROSS THE UPPER MIDWEST TONIGHT AND THE NEXT STRONG TROUGHING/ ENERGY TO CROSS THE ROCKIES SUN/SUN NIGHT. SLOWER/STRONGER ECMWF/ CAN-GEM OFFERING THE BETTER RUN-TO-RUN CONSISTENCY WITH THE ROCKIES TROUGHING LATE SUN/SUN NIGHT WITH GFS/NAM SLOWING TO MATCH UP. NAM APPEARS AS BIT OF AN OUTLIER AT 12Z MON WITH A FURTHER NORTH/EAST SFC LOW/TRAILING COLD FRONT AND ITS SOLUTION GENERALLY DISCOUNTED. GIVEN THE NOW RATHER TIGHT NON- NAM CONSENSUS THRU 12Z MON...SHORT- TERM FCST CONFIDENCE FOR A RATHER ACTIVE PERIOD IS GOOD THIS CYCLE. FIRST SHORTWAVE CROSSING THE UPPER MIDWEST TONIGHT WEAKENS AS LOOSES THE BATTLE WITH THE RISING HGTS/RIDGING AHEAD OF THE STRONGER TROUGHING DIGGING INTO THE ROCKIES. 925-700MB MOISTURE TRANSPORT/ WARM ADVECTION AND SOME 295-305K ISENTROPIC LIFT STILL SPREADS NORTHEAST ACROSS THE FCST AREA MAINLY LATE THIS AFTERNOON/EVENING... WITH STEEPER MID LEVEL LAPSE RATES AND WEAK INSTABILITY. WILL CONTINUE SHRA/TSRA CHANCES THRU THE EVENING...IN THE 20-50 PERCENT RANGE...THEN TAPER/END THEM AFTER MIDNIGHT AS THE LOWER LEVEL FORCING WEAKENS/MOVES EAST OF THE FCST AREA. MOST RAIN AMOUNTS TONIGHT TO BE QUITE LIGHT. BREAK FROM THE RAIN CHANCES LATE TONIGHT/SUN MORNING AS SOME 850- 700MB DRYING TEMPORARILY SPREADS ACROSS THE AREA. MOISTURE RETURN AHEAD OF THE CENTRAL PLAINS LEE LOW ALREADY SPREAD ACROSS THE AREA SUN MORNING...WITH THE 700MB MOISTURE ARRIVING DURING THE LATER MORNING/EARLY AFTERNOON HOURS AND 925-50MB MOISTURE ARRIVING DURING THE AFTERNOON. PW VALUES OF AROUND 1.5 INCHES TO SPREAD NORTH ACROSS THE AREA FOR SUN AFTERNOON/NIGHT. QUESTION NO LONGER SEEMS IF ITS GOING TO RAIN LATE SUN AFTERNOON/NIGHT BUT HOW MUCH. BROAD/DEEP LAYERED FORCING/LIFT AHEAD OF THE SFC THRU MID LEVEL TROUGH SPREADS ACROSS WITH THE MOISTURE INCREASE SUN AFTERNOON/NIGHT. AT 00Z MON...MODEL SOUNDINGS SHOWING STABILITY/CIN OF 50-150IN THE SFC-700MB LAYER WITH MUCAPES OF 500-1500 J/KG OVER MAINLY THE SOUTH 1/3 OF THE FCST AREA. LFC AROUND 700MB IN THE SOUNDINGS WITH THE CIN IN A RATHER DEEP 900-700MB LAYER. CAPE PROFILE IS DEEP...BUT SKINNY. WITH WARM CLOUD DEPTH OF AROUND 3500 METERS...THE SKINNY CAPE OF 500- 1500 J/KG DOES NOT SEEM LIKE ENOUGH FOR A BIG HAIL THREAT. WITH THE AREA LOOKING TO BE NORTH OF THE WARM FRONT SUN EVENING AND THE CIN BELOW 700MB...APPEARS MAIN TORNADO AND STRONG WIND THREAT WOULD BE SOUTH OF THE FCST AREA. ALSO...NUMEROUS SHRA/TSRA EXPECTED TO BE SPREADING INTO/ACROSS THE AREA SUN AFTERNOON/ EVENING...ALL COMPETING FOR THE SAME CAPE/SHEAR...WILL REDUCE THE SEVERE THREAT FROM ANY ONE TSRA. CONCERNS AS WELL ON SUN WITH HIGH TEMPS BEING TOO WARM AND CAPE ON THE HIGH SIDE GIVEN THICKENING CLOUDS/SHRA/TSRA SPREADING NORTH INTO THE AREA DURING THE AFTERNOON. THE 3500 METER WARM CLOUD DEPTH...A WARM FRONT TO THE SOUTH FOR LIFTING...PW VALUES NEAR 200 PERCENT OF NORMAL AND A FEED OF THIS MOISTURE ON A 40-50KT 850MB JET SUN NIGHT ALL POINT TSRA BEING EFFICIENT RAIN MAKERS AND A HEAVY RAIN THREAT. CONSIDERED A FLOOD WATCH FOR SUN NIGHT/MON...BUT IT WOULD HAVE AND TO BE RATHER BROAD WITH QPF DETAIL DIFFERENCES AMONG THE MODELS. WILL ISSUE AND ESF FOR NOW AND PASS ALONG CONCERNS TO THE MIDNIGHT CREW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 310 PM CDT SAT MAY 10 2014 MAIN FORECAST CONCERNS MON THRU TUE NIGHT...SHRA/TSRA CHANCES/RAIN AMOUNTS MON INTO MON NIGHT...COOLING TEMPERATURES. MODEL RUNS OF 10.12Z OFFERING A TIGHTER CONSENSUS MON/MON NIGHT AS THE MID LEVEL TROUGH LIFTS INTO THE UPPER MIDWEST AND THE SFC LOW LIFTS TO LK SUPERIOR. TREND IS TOWARD COMPROMISE OF THE EARLIER RUNS ON STRENGTH/TIMING OF THE MID LEVEL TROUGH INTO THE REGION WITH SOMEWHAT BETTER RUN-TO-RUN CONSISTENCY BY THE ECMWF. IMPROVING CONSENSUS TUE/TUE NIGHT AS THE TROUGH VIRTUALLY STALLS OVER THE CENTRAL CONUS. FCST CONFIDENCE IN THE MON-TUE NIGHT PERIOD IS AVERAGE TO GOOD THIS CYCLE. BROAD/DEEP FORCING/LIFT CONTINUES OVER THE AREA MON...ALONG WITH A FEED OF THE 1.5 INCH PW VALUES ON A 30-40KT 850MB JET. STRONGEST OF THIS IS OVER THE FCST AREA IN THE MORNING...GRADUALLY TRANSLATING EAST MON AFTERNOON/EVENING AS THE SFC THRU 850MB COLD FRONT/TROUGH MOVE EAST INTO/ACROSS THE AREA. PLENTY OF FORCING/LIFT REMAINS OVER THE WEST SIDE OF THE FCST AREA MON AFTERNOON/EVENING...WITH THE 700- 500MB TROUGH AXIS STILL WEST OF THE AREA AND SHORTWAVES LIFT UP THE EAST SIDE OF THE TROUGH THRU WESTERN MN. HEAVIEST RAIN THREAT SHIFTS EAST OF THE AREA THRU MON AFTERNOON/EVENING...BUT SHRA/TSRA LOOK TO CONTINUE ACROSS THE ENTIRE FCST AREA MON AFTERNOON. AFTER A POSSIBLE 1 TO 2 INCHES OF RAIN SUN NIGHT...ANOTHER 1/4 TO 3/4 INCH OF RAIN POSSIBLE MONDAY. SHRA/TSRA THEN TAPER OFF AND EXIT EAST THRU MON NIGHT/TUE MORNING AS THE SFC-850MB TROUGH/FRONT MOVE EAST OF THE AREA. CONCERNS WITH THE SEVERE THREAT DEPICTED IN DAY 3 SIMILAR TO THOSE CENTERED ON SUN EVENING. SHRA/TSRA SHOULD BE ONGOING ACROSS MUCH OF THE UPPER MIDWEST MON MORNING...AND CONTINUE MUCH OF THE DAY. DEBRIS CLOUDS AND THE RAIN SHOULD LIMIT HIGH TEMPS AND POTENTIAL FOR CAPE TO BUILD ACROSS THE AREA. USED THE MODEL/ENSEMBLE CONSENSUS HIGHS FOR MON BUT IF CLOUDS/SHRA/TSRA PREVAIL...THESE ARE LIKELY TOO WARM RESULTING IN TOO MUCH CAPE IN THE PROGS. MON CAPE PROFILES ALSO DEEP AND SKINNY SIMILAR TO SUN EVENING. NUMEROUS SHRA/TSRA ALL COMPETING FOR THE SAME CAPE/SHEAR WILL AGAIN LIMIT THE SEVERE POTENTIAL WITH ANY ONE STORM. DRIER/COOLER 925-700MB AIR WRAPS ACROSS THE AREA FOR TUE AFTERNOON/ NIGHT FOR WHAT SHOULD BE DRY PERIODS AND A DECREASE OF CLOUDS. 850MB TEMPS IN THE +2C TO -1C RANGE BY 12Z WED. THIS PLUS LIGHT WINDS AND MOSTLY CLEAR SKIES TUE NIGHT...LOWS IN THE UPPER 30S-LOW 40S WED MORNING APPEAR REASONABLE. FOR WEDNESDAY THRU SATURDAY.../DAYS 4 TO 7/... MAIN FORECAST CONCERNS THIS PERIOD...COOL TEMPERATURES AND -SHRA CHANCES THRU THE PERIOD. MEDIUM RANGE MODEL RUNS OF 10.00Z/10.12Z HAVE COME INTO BETTER AGREEMENT WED/THU ON LOCATION/STRENGTH OF THE TROUGHING TO SLOWLY MOVE ACROSS CENTRAL NOAM. MODELS CONVERGING TOWARD THE EARLIER ECMWF RUNS. IMPROVING CONSENSUS FOR SOME NORTHERN STREAM ENERGY TO DROP INTO THE UPPER MIDWEST THU/FRI...FURTHER DEEPENING THE TROUGH AND CARVING OUT A MID LEVEL OVER THE WESTERN GREAT LAKES FOR FRI INTO SAT. GIVEN THE IMPROVED MEDIUM RANGE MODEL CONSENSUS...DAY 4-7 FCST CONFIDENCE IS GENERALLY GOOD THIS CYCLE...ESPECIALLY FOR BELOW NORMAL TEMPERATURES. ONE SURGE OF COLDER LOW LEVEL HAS ALREADY SETTLED OVER THE REGION BY WED. A SECONDARY...EVEN COLDER SURGE IS POISED TO DROP SOUTH INTO THE REGION FOR THU/FRI. 850MB TEMPS PROGGED TO BOTTOM OUT IN THE -1C TO -3C RANGE AT 12Z FRI. SOME TEMP RECOVERY SAT AS WARMER AIR ACTUALLY WRAPS IN FROM THE NORTH. SIGNAL REMAINS CONSISTENT FOR 850MB TEMPS TO BE SOME 1.5 TO 2 STANDARD DEVIATIONS BELOW NORMAL ACROSS THE UPPER MIDWEST FOR MOST OF THE WE-SAT PERIOD. CONFIDENCE IS GOOD FOR DAY 4-7 HIGHS TO BE SOME 10-15F BELOW NORMAL. LOWS THRU THE PERIOD A LITTLE TRICKER AND DEPENDENT ON EXTENT OF CLOUD COVER ANY ONE NIGHT. WITH MODEST 925-700MB MOISTURE AND THE DEEP COLD CORE TROUGH/LOW AND CYCLONIC FLOW OVER THE REGION...CLOUDS EXPECTED TO PREVAIL MUCH OF THE WED-SAT PERIOD. IF ANY ONE OF THE NIGHTS ENDS UP MORE CLEAR THAN CLOUDY...PATCHY FROST WOULD BE EXPECTED...ESPECIALLY ALONG/NORTHEAST OF I-94 THU/FRI NIGHTS. FOR NOW THE MODEL/ENSEMBLE CONSENSUS HIGHS/LOWS FOR WED- SAT ARE WELL TRENDED. LESS CONFIDENCE ON -SHRA CHANCES IN THE WED-SAT PERIOD AS THESE CHANCES WILL DEPEND ON THE TIMING OF STRONGER SHORTWAVES THRU THE PERSISTENT TROUGHING OVER THE REGION. PRESENT TIMING HAS ONE STRONGER SHORTWAVE DROPPING INTO THE REGION WED THEN MORE SHORTWAVE ENERGY ROTATING AROUND THE DEEP TROUGH/MID LEVEL LOW OVER THE WESTERN GREAT LAKES FRI/SAT. WITH THE DEEP CYCLONIC FLOW...COLD CORE OF 850-700MB TEMPS OVER THE REGION...STEEP SFC- 700MB LAPSE...RATES/WEAK INSTABILITY DURING THE AFTERNOON HOURS...ANY SHORTWAVE WOULD BE CAPABLE OF TRIGGERING SCT -SHRA. SMALL -SHRA CHANCES MUCH OF THE WED-SAT PERIOD STILL LOOK REASONABLE UNTIL THE SHORTWAVE TIMING DETAILS CAN BE SORTED OUT. ANY PRECIP DURING THE WED-SAT WOULD BE SCT AND LIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1207 PM CDT SAT MAY 10 2014 SMALL AREA OF LIGHT SHOWERS/SPRINKLES CONTINUES TO ADVANCE NORTHEAST AHEAD OF A WEAK SHORT WAVE TROUGH. THE 10.14Z HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE SHOWERS AND BRINGS THEM EASTWARD WHILE WEAKENING THEM. WILL SHOW A VCSH FOR THESE SHOWERS THROUGH ABOUT THE MIDDLE OF THE AFTERNOON. THERE SHOULD THEN BE A BREAK IN THE ACTIVITY BEFORE THE NEXT SHORT WAVE TROUGH COMES IN AND BRINGS ANOTHER CHANCE FOR SOME ACTIVITY. EXPECTING THIS NEXT ROUND OF ACTIVITY TO APPROACH THE TAF SITES AROUND 00Z AND THERE COULD BE SOME THUNDER WITH IT AS THE 10.12Z NAM BUFKIT SOUNDINGS SHOW 200-400 J/KG OF ELEVATED SKINNY CAPE. WILL HAVE A VCTS FOR THIS NEXT ROUND BASED ON THIS AVAILABLE CAPE...BUT NOT SURE HOW LONG TO HOLD ONTO THE CHANCES AS THE HRRR WOULD PUSH IT THROUGH DURING THE EVENING HOURS WHILE THE NAM WOULD HOLD ONTO SOME CHANCES THROUGH MUCH OF THE NIGHT. FOR NOW...WILL LIMIT THE CHANCES TO THE EVENING HOURS AS BOTH THE 10.12Z GFS AND 10.00Z ECMWF WOULD ALSO SUGGEST THE BETTER CHANCES WILL BE IN THE EVENING. THROUGH THE ENTIRE PERIOD...THE BEST MOISTURE LOOKS TO BE MAINLY IN THE MID LEVELS SO EXPECT CEILINGS TO REMAIN VFR. && .HYDROLOGY... ISSUED AT 310 PM CDT SAT MAY 10 2014 MINOR FLOODING/HIGH WATER CONTINUES ALONG PORTIONS OF THE MISSISSIPPI RIVER. LATER SUN AFTERNOON INTO MON EVENING WILL BE A WET PERIOD...WITH POTENTIAL FOR 1 TO 2 OR MORE INCHES OF RAINFALL DURING THAT PERIOD. THE HEAVIEST RAIN/HIGHEST TOTALS WILL FALL SUNDAY NIGHT INTO MONDAY MORNING. THESE RAINS COULD HAVE ADDITIONAL IMPACTS ON BOTH TRIBUTARIES AND THE MISSISSIPPI RIVER...SLOWING THE RATES OF FALL...PRODUCE ADDITIONAL RISES OR RENEWED FLOODING. WILL ISSUE AN ESF CONCERNING THE POTENTIAL HEAVY RAINS SUN NIGHT/MON AND RISING RIVER LEVELS/FLOODING THREAT. CHECK THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RRS LONG TERM....RRS AVIATION.....04 HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1207 PM CDT SAT MAY 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 300 AM CDT SAT MAY 10 2014 GFS/NAM IN GOOD AGREEMENT WITH SPINNING AN UPPER LEVEL SHORTWAVE TROUGH ACROSS THE NORTHERN PLAINS THIS AFTERNOON...TRACKING ACROSS THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT. 500-1000 J/KG MUCAPE VIA THE GFS/NAM AT 00Z ACROSS SOUTHERN MN/WESTERN WI FOR THE SHORTWAVE TO WORK ON. BUFKIT SOUNDINGS POINT TO SKINNY CAPE THOUGH...NOT FAVORABLE FOR STRONG UPDRAFTS. SOME 0-6 KM SHEAR BY 06Z...40-50 KTS...BUT THE INSTABILITY IS WEAKENED/NIL BY THAT TIME. THIS SYSTEM IS PACKING A BIT MORE PUNCH THAN PREVIOUS MODEL RUNS SUGGESTED...MAKING A PERIOD OF SHOWERS/STORMS MORE LIKELY FOR THE SAT NIGHT. SOME HINTS THAT THE CENTER OF THE FORECAST AREA COULD MISS OUT ON MOST OF THE ACTIVITY...WITH A PIECE OF THE LOW LEVEL MOISTURE TRANSPORT INTO THE SHORTWAVE...WHILE THE BULK OF IT FOCUSES INTO A WEST-EAST RUNNING WARM FRONT ACROSS THE IA/MO BORDER. DRY SUB CLOUD LAYER PER SOUNDINGS SUGGEST SOME ENHANCED GUSTINESS POSSIBLE AROUND ANY OF THE ANTICIPATED STORMS. SKINNY CAPE WOULDN/T SUPPORT LARGE HAIL FORMATION...ALTHOUGH SOME PEA SIZED CAN/T BE RULED OUT. OVERALL...SEVERE THREAT LOOKS MINIMAL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 230 AM CDT SAT MAY 10 2014 WEST COAST LONGWAVE UPPER LEVEL TROUGH GOING TO SLOWLY PUSH INTO THE PLAINS SUN/MON...EJECTING PIECES OF ENERGY NORTHEAST TOWARD THE LOCAL AREA. A COLD FRONT/SFC LOW DEVELOPS IN RESPONSE TO THE FORCING...EXTENDING FROM CENTRAL MN INTO THE SOUTHERN PLAINS BY 00Z MON...GRADUALLY EASING INTO EASTERN WI MONDAY NIGHT. LOW LEVEL MOISTURE TRANSPORT RAMPS UP AHEAD OF A SFC FRONT...WITH THE NOSE OF A 40-50 KT 850 MB POINTING INTO SOUTHWEST WI SUN EVENING. THE STEADY RIBBON OF LOW LEVEL MOISTURE PERSISTS ALONG/AHEAD OF THE SFC FRONT INTO MONDAY. GFS/NAM A BIT MORE BULLISH ON THE INSTABILITY WITH THEIR 00Z RUNS COMPARED TO PREVIOUS DAYS...WITH 1000-2000 J/KG OF MUCAPE PUSHING ACROSS WESTERN WI BY 18-00Z SUN/MON. 0-6 KM SHEAR 45-50 KTS BY 00Z...WITH 30+ KTS IN THE 0-3 KM LAYER. SEVERE PARAMETERS INCREASING FOR THE FORECAST AREA. PW/S CLIMB TO OVER 1 1/2 INCHES. THE HIGHER SEVERE THREAT WILL CONTINUE TO BE TO THE SOUTH...BUT THE THREAT FOR STRONG/SEVERE STORMS IS INCREASING. A LOT IS UNCERTAIN...AS IN WHERE VARIOUS SFC BOUNDARIES FROM PREVIOUS CONVECTION COULD LIE...IF ANY CONVECTION WILL GET GOING BEFORE THE MAIN SURGE OF LOW LEVEL MOISTURE/FORCING SUN EVENING...HOW MUCH A SOUTHERN BOUNDARY/WARM FRONT WILL IMPACT SEVERE POTENTIAL ADVANCING NORTH ETC. IT SHOULD BE NOTED THAT SOUNDINGS LEAN TOWARD A SKINNY CAPE PROFILE TOO...AGAIN...NOT FAVORABLE FOR STRONG UPDRAFTS/EXPLOSIVE GROWTH. STAY TUNED. PERIODS OF SHOWERS WILL PERSIST FOR MUCH OF MONDAY AS THE UPPER LEVEL TROUGH STILL HANGS JUST EAST AND THE COLD FRONT TAKES ITS TIME GOING EAST. GFS/ECMWF FAVOR KEEPING THE REGION UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGH INTO NEXT WEEKEND. THE PERSISTENT NORTHWEST FLOW WILL USHER IN ANOTHER ROUND OF COLDER AIR...WITH 850 MB TEMP ANOMALIES VIA THE EC AROUND -1 MUCH OF THE WEEK. HIGHS WILL PROBABLY STRUGGLE TO REACH 60 MANY OF THE DAYS. MEANWHILE...SOME DIFFERENCES BETWEEN THE EC AND GFS ON WHETHER OR NOT RIPPLES IN THE UPPER LEVEL FLOW WILL TRACK ACROSS THE REGION...AND THEN...IF THERE WOULD BE ANY PCPN CHANCES WITH THEM. CONFIDENCE LOW IN THESE DETAILS...SO WILL STICK WITH THE CONSENSUS SOLUTION FOR THE MOMENT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1207 PM CDT SAT MAY 10 2014 SMALL AREA OF LIGHT SHOWERS/SPRINKLES CONTINUES TO ADVANCE NORTHEAST AHEAD OF A WEAK SHORT WAVE TROUGH. THE 10.14Z HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE SHOWERS AND BRINGS THEM EASTWARD WHILE WEAKENING THEM. WILL SHOW A VCSH FOR THESE SHOWERS THROUGH ABOUT THE MIDDLE OF THE AFTERNOON. THERE SHOULD THEN BE A BREAK IN THE ACTIVITY BEFORE THE NEXT SHORT WAVE TROUGH COMES IN AND BRINGS ANOTHER CHANCE FOR SOME ACTIVITY. EXPECTING THIS NEXT ROUND OF ACTIVITY TO APPROACH THE TAF SITES AROUND 00Z AND THERE COULD BE SOME THUNDER WITH IT AS THE 10.12Z NAM BUFKIT SOUNDINGS SHOW 200-400 J/KG OF ELEVATED SKINNY CAPE. WILL HAVE A VCTS FOR THIS NEXT ROUND BASED ON THIS AVAILABLE CAPE...BUT NOT SURE HOW LONG TO HOLD ONTO THE CHANCES AS THE HRRR WOULD PUSH IT THROUGH DURING THE EVENING HOURS WHILE THE NAM WOULD HOLD ONTO SOME CHANCES THROUGH MUCH OF THE NIGHT. FOR NOW...WILL LIMIT THE CHANCES TO THE EVENING HOURS AS BOTH THE 10.12Z GFS AND 10.00Z ECMWF WOULD ALSO SUGGEST THE BETTER CHANCES WILL BE IN THE EVENING. THROUGH THE ENTIRE PERIOD...THE BEST MOISTURE LOOKS TO BE MAINLY IN THE MID LEVELS SO EXPECT CEILINGS TO REMAIN VFR. && .HYDROLOGY... ISSUED AT 300 AM CDT SAT MAY 10 2014 MINOR FLOODING/HIGH WATER CONTINUES ALONG PORTIONS OF THE MISSISSIPPI RIVER. TODAY THROUGH MONDAY WILL BE A WET PERIOD...WITH ADDITIONAL AMOUNTS FROM 1 TO 2 INCHES POSSIBLE. THE HEAVIEST RAIN/HIGHEST TOTALS WILL FALL SUNDAY NIGHT. THESE RAINS COULD HAVE ADDITIONAL IMPACTS ON BOTH TRIBUTARIES AND THE MISSISSIPPI RIVER...SLOWING THE RATES OF FALL OR PRODUCE ADDITIONAL RISES. CHECK THE LATEST HYDROLOGIC STATEMENTS FOR THE DETAILS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04 HYDROLOGY....RIECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1118 PM MDT SUN MAY 11 2014 .UPDATE... ISSUED AT 1108 PM MDT SUN MAY 11 2014 UPDATED TO CANCEL WINTER WX ADVISORY FOR SOUTHERN EL PASO COUNTY AND TO ADD OTERO COUNTY TO THE FREEZE WARNING. ALSO ADJUSTED SNOW AMOUNTS FOR TONIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 258 PM MDT SUN MAY 11 2014 ...SIGNIFICANT SNOWS EXPECTED TO CONTINUE ACROSS THE CENTRAL MOUNTAINS AND PIKES PEAK REGION... UPPER LOW NEARING THE FOUR CORNERS REGION THIS AFTERNOON WILL BE LIFTING NORTHEASTWARD OVERNIGHT INTO NORTHEAST CO BY 18Z MONDAY. SURFACE FRONT HAS PUSHED THROUGH ALL OF THE SOUTHEAST PLAINS AS OF 21Z. SNOWFALL AMOUNTS SO FAR HAVE BEEN HIGHLY DETERMINED BY THE SNOW LEVELS AND WARM GROUND. PIKES PEAK REGION HAS ALREADY DROPPED INTO THE LOWER TO MID 30S...WITH UPPER 20S ACROSS TELLER COUNTY. THIS HAS BEEN THE AREA WHICH HAS RECEIVED THE MOST SNOW...THOUGH A LOOK AT WEB CAMS ACROSS THE AREA SHOWS THAT WARM GROUND HAS MITIGATED ACCUMULATIONS SOME. MAINLY GRASSY SURFACES HAVE ACCUMULATION...BUT OCCASIONALLY HAVE SEEN SOME SNOW ON THE PAVEMENT DURING THE HEAVIER SNOW BURSTS. STILL WAITING FOR SNOW LEVELS TO DROP ACROSS THE UPPER ARKANSAS RIVER VALLEY...WITH SALIDA AND BUENA VISTA AIRPORTS STILL IN THE 40S AS OF 21Z. DOWN AROUND COLORADO CITY AND RYE...TEMPERATURES ARE STILL IN THE UPPER 30S AND LOWER 40S...BUT TEMPERATURES HAVE BEEN DROPPING QUICKLY THIS LAST HOUR AND SUSPECT RAIN/SNOW SWITCH OVER FOR THE UPPER ARKANSAS RIVER VALLEY OF FREMONT AND CHAFFEE AND THE LOWER ELEVATION OF THE WET MOUNTAINS IS NOT LONG OFF. AS FOR HIGHLIGHTS...HAVE LEFT THEM AS IS. A LITTLE CONCERNED THAT LATER SWITCH OVER TO SNOW ACROSS LOWER ELEVATIONS OF CHAFFEE COUNTY MAY HURT SNOW TOTALS SOME...BUT BEST FORCING WILL CONTINUE TO TREK ACROSS THIS AREA THROUGH THE EVENING...AND LATEST 18Z NAM IS NOW HITTING THIS AREA WITH AROUND 4 INCHES OF SNOW THROUGH THE EVENING HOURS. ONCE THE SWITCH OVER OCCURS...IT WILL NOT TAKE LONG FOR ACCUMULATIONS TO START STACKING UP...THOUGH SUSPECT THE WARM GROUND WILL MAKE FOR A WIDE RANGE OF ACCUMULATIONS WITH LOCATIONS LIKE SALIDA COMING UP ON THE LOW END. ON THE FENCE WITH UPGRADING TO A WINTER STORM WARNING FOR THE LOWER ELEVATIONS OF THE WET MOUNTAINS AND THE NORTHERN SANGRE DE CRISTO MOUNTAINS. THERE COULD BE A FEW AREAS THAT HIT AROUND 12 INCHES...BUT THE LATE TRANSITION OVER TO SNOW WILL LARGELY KEEP AMOUNTS MORE IN THE ADVISORY RANGE. AS FOR TIMING OF THE HEAVIER SNOWS...HEAVIEST SHOULD FALL NOW THROUGH MIDNIGHT. AFTER MIDNIGHT...BEST FORCING SHIFTS NORTH OF THE AREA...AND ALTHOUGH THERE WILL STILL BE SOME WRAP AROUND SNOWS ACROSS THE CENTRAL MOUNTAINS/PIKES PEAK AREA...DOWNSLOPE NORTHERLY WINDS OFF THE PALMER DIVIDE SHOULD OPEN UP THE PRECIPITATION MINIMUM ACROSS SOUTHERN EL PASO AND NORTHERN PUEBLO COUNTIES. THIS COULD OCCUR AS EARLY AS 10 PM. WINTER WEATHER ADVISORIES FOR SOUTHERN EL PASO COUNTY MAY RUN A TAD TOO LONG...BUT WILL LET LATER SHIFTS MONITOR TRENDS AND MAKE ANY NEEDED ADJUSTMENTS. THE WET MOUNTAINS AND SOUTHERN I-25 CORRIDOR WILL SEE MORE CONVECTIVE BURSTS OF RAIN/SNOW...WHICH SHOULD SWITCH OVER TO ALL SNOW BY AROUND 6 PM. HOWEVER...MAJORITY OF THE HEAVIER SNOW MAY BE DONE BY 6 AM...AND POSSIBLY EVEN SOONER IF LATEST HRRR IS CORRECT. AS FOR THE SOUTHEAST PLAINS...HAVE EXTENDED THE FREEZE WARNING TO INCLUDE CROWLEY COUNTY...AS AM GETTING A FEW HOURS OF SUBFREEZING TEMPERATURES THERE. NOT MUCH SNOW IS EXPECTED...THOUGH SWITCH OVER COULD OCCUR AROUND 6 PM FOR PUB...AROUND MIDNIGHT FOR LHX...AND EVEN LATER FOR POINTS FARTHER EAST WHERE IT MAY STAY ALL RAIN...OR GO TO A BRIEF RAIN/SNOW MIX TOWARDS MORNING BEFORE IT ENDS. GRASSY SURFACES AROUND PUEBLO...WALSENBURG...TRINIDAD COULD SEE AN INCH OR TWO AT ANY TIME...BUT WARM GROUND MAY MELT IT OFF QUICKLY. ON MONDAY...ANOTHER TRAILING DISTURBANCE DROPS IN IN NORTHWEST FLOW ALOFT...AND SENDS ANOTHER ROUND OF SNOW INTO THE MOUNTAIN AREAS...PARTICULARLY ALONG THE CONTINENTAL DIVIDE. THIS CONTINUES INTO MONDAY EVENING. ITS POSSIBLE THESE AREAS MAY NEED ANOTHER HIGHLIGHT...MOST LIKELY AN ADVISORY...BUT SINCE THERE SEEMS TO BE A DISTINCT BREAK BETWEEN THE TWO SYSTEMS...WILL LET LATER SHIFTS DETERMINE WHAT IF ANY HIGHLIGHTS WILL BE NEEDED. SUSPECT THAT TO SOME EXTENT...THE HIGHER SNOWFALL AMOUNTS IN THE GFS MAY BE A TAD OVERDONE DUE TO SOME CONVECTIVE COMPONENT...AND HAVE GONE CLOSER TO THE NAM FOR NOW. -KT .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 258 PM MDT SUN MAY 11 2014 SECONDARY UPPER LOW AND UPSLOPE FLOW WILL KEEP SOME SNOW GOING OVER THE SAN JUANS/SANGRES MON EVENING...AND SOME ADDITIONAL LIGHT ACCUMULATION IS POSSIBLE WITH BEST CHANCE OVER THE EASTERN SAN JUANS. PRECIP THEN SLOWLY SHIFTS SOUTH OVERNIGHT AS UPPER TROUGH MOVES EAST...WHICH WILL END MOST ACCUMULATING SNOW BY EARLY TUESDAY MORNING. MANY AREAS WILL HAVE THE POTENTIAL FOR FREEZING TEMPS ONCE AGAIN BY EARLY TUE MORNING...THOUGH AMOUNT OF MID LEVEL CLOUDINESS MAY BE THE DETERMINING FACTOR ON HOW WIDESPREAD COLD TEMPS BECOME. VERY GRADUAL WARMING AND DRYING TREND BEGINS TUESDAY AFTERNOON...THOUGH SOME RESIDUAL MOISTURE/INSTABILITY OVER THE MOUNTAINS MAY PRODUCE A FEW LIGHT SHOWERS TUE AFTERNOON. NEUTRAL TO WEAK WARM ADVECTION...COMBINED WITH INCREASING MAY SUN SHOULD BOOST MAX TEMPS SEVERAL DEGF VERSUS MONDAYS HIGHS...THOUGH READINGS WILL STILL RUN WELL BELOW SEASONAL AVERAGES. ANOTHER THREAT OF SOME PATCHY FROST TUE NIGHT/WED MORNING AS SKIES CLEAR...ESPECIALLY EL PASO COUNTY/LOW LYING AREAS OF PUEBLO COUNTY. UPPER RIDGE THEN BUILDS OVER THE WESTERN U.S. FOR MID-WEEK...THEN GRADUALLY FLATTENS NEXT WEEKEND. IN GENERAL...GRADUAL WARMING/DRYING TREND IN STORE FOR THE AREA THROUGH THE PERIOD...THOUGH A COUPLE WAVES EMBEDDED IN THE NW FLOW MAY PRODUCE AT LEAST SOME ISOLATED -TSRA/-SHRA OVER THE EASTERN MOUNTAINS AND PLAINS THU/FRI AS MODEST LOW LEVEL MOISTURE RETURNS SLOWLY INTO THE HIGH PLAINS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1108 PM MDT SUN MAY 11 2014 KALS...VFR CONDITIONS EXPECTED FOR ALS FOR THE NEXT 24 HRS...WITH SHOWERS IN THE VCNTY THROUGH 18Z TODAY. AFTER 18Z...A BRIEF BREAK THEN SHOWERS WILL REDEVELOP OVER THE MTS TO THE WEST. KCOS AND KPUB...IFR CONDITIONS WITH -SHRASN IN THE VCNTY THROUGH 18Z AND STRONG NORTH WINDS WITH GUSTS UP TO 35 MPH EXPECTED. VFR CONDITIONS THEN DEVELOPING AFTER 18Z AS THE UPPER SYSTEM LIFTS OUT TO THE EAST. MOORE && .PUB WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 8 AM MDT MONDAY FOR COZ083>089-093-094. WINTER STORM WARNING UNTIL 9 AM MDT MONDAY FOR COZ058>063-073- 076-080>082-084. WINTER WEATHER ADVISORY UNTIL 9 AM MDT MONDAY FOR COZ072-074-075- 077>079. WINTER WEATHER ADVISORY UNTIL 6 AM MDT MONDAY FOR COZ066-068. && $$ UPDATE...28 SHORT TERM...KT LONG TERM...PETERSEN AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 AM CDT MON MAY 12 2014 .DISCUSSION... 930 PM CDT STORMS ACROSS THE FAR SOUTHERN FORECAST AREA HAVE SHOWN A CONSISTENT WEAKENING TREND IN THE PAST HOUR. STILL SOME CONVERGENCE ON THE OUTFLOW BOUNDARY WITH WARM/MOIST ADVECTION 850-925MB ADVECTION INTO THIS AREA. SO SOME REGENERATION OF STORMS MAY CONTINUE AS RADAR TRENDS HAVE INDICATED IN MCCLEAN COUNTY...ALTHOUGH THE REFLECTIVITY TREND IS GENERALLY DOWNWARDS. SO THE FLOODING THREAT IS GRADUALLY DIMINISHING. TEMPORARY SUPPRESSION AND MID-LEVEL DRYING BEHIND MCS SHOULD KEEP MUCH OF THE FORECAST AREA QUIET THROUGH 3 AM OR SO. WIDESPREAD CONVECTION ACROSS WESTERN IOWA SHOULD EVOLVE EAST NORTHEAST WITH POSSIBLE SCATTERED DEVELOPMENT AHEAD OF THIS ON THE LOW-LEVEL JET AND JUST INCREASING UPPER/MID-LEVEL FORCING. THIS IS MOST FAVORED IN NORTH CENTRAL ILLINOIS...INCLUDING TOWARD ROCKFORD. THIS WOULD HAVE A SMALL SEVERE WEATHER CHANCE. OVERALL BUILDING HEIGHTS SHOULD LIMIT A WELL-DEVELOPED MCS FROM THE WEST MOVING INTO THE FORECAST AREA. MTF //PREV DISCUSSION... 300 PM CDT FORECAST CONCERNS ARE MAINLY ON THE IMMEDIATE SEVERE WEATHER CHANCES THROUGH EARLY/MID EVENING. ALSO FOCUS ON THE SEVERE WEATHER POTENTIAL ON MONDAY...PRIMARILY MONDAY LATE AFTERNOON INTO THE NIGHTTIME PERIOD. OVERNIGHT INTO MONDAY MORNING... STRONG UPPER JET WILL PROPAGATE AROUND THE UPPER TROUGH LATE TONIGHT INTO THE MORNING ON MONDAY AND WITH THAT LEAD TO FURTHER AMPLIFYING OF THE UPSTREAM RIDGE...INCLUDING BUILDING HEIGHTS ACROSS MUCH OF THE FORECAST AREA. MUCH OF THE FORCING FOR RAIN/STORMS IN THIS PERIOD WOULD BE FOCUSED TO THE WEST AND NORTH IN SUCH A PATTERN. THE STRONG LOW-LEVEL JET WILL AT LEAST IN PART BE OVER THE AREA...HOWEVER THE NOSE OF IT WILL BE POINTED FURTHER NORTH. CONVECTIVE CHANCES LOOK MINIMAL AND MAINLY THE NORTHWEST FORECAST AREA TOWARD ROCKFORD. CHANCES MAY BE INCREASED SOMEWHAT IF ANY ORGANIZED CONVECTION FROM THE CENTRAL PLAINS WERE TO PROPAGATE EASTWARD INTO NORTHERN IL...BUT THE GRADUALLY MORE MERIDIONAL FLOW AND ORIENTATION OF FORECAST CORFIDI VECTORS WOULD PUSH MUCH OF THE CONVECTION NORTH OF THE AREA. LOW TEMPS WILL BE BALMY WITH CONTINUED SOUTHERLY FLOW AND HIGH DEW POINT AIR...WITH SOME PLACES EXPERIENCING SOME WARMING OF TEMPS LATER THIS EVENING...ESPECIALLY THOSE IMPACTED BY EARLY EVE CONVECTION AND THOSE COMMUNITIES NEAR THE LAKE SHORE THAT HAD AFTERNOON/EVE COOLING. MONDAY AFTERNOON THROUGH TUESDAY... THE UPPER TROUGH WILL CONTINUE TO AMPLIFY AS THE UPPER JET TO ITS FRONT AND BACK INTENSITY. A WARM AND MUGGY DAY IS ANTICIPATED MONDAY. CONVECTIVE INHIBITION ON MONDAY AFTERNOON DOES LOOK TO BE OVERCOME BUT A FOCUS IS NOT OVERLY EVIDENT IN OUR FORECAST AREA. GRADUALLY MORE CONVERGENCE AND INCREASING DEEP LAYER MOISTURE AND UPWARD MOTION IS FORECAST TO MOVE EASTWARD ACROSS MAINLY NORTH CENTRAL ILLINOIS LATE IN THE DAY INTO EARLY EVE AND EASE ITS WAY EASTWARD THROUGH THE REMAINDER OF THE NIGHT. THIS LOOKS LIKE A PERIOD OF STORMS MOVING NORTHEAST WITHIN THE DEEP MOIST PLUME. THE SEVERE POTENTIAL WOULD SEEM MOST FAVORED WITH THE INITIAL CONVECTION IN THE LATE AFTERNOON/EVE AND THEN A GENERAL WANING LATER INTO THE NIGHT. LOCALLY HEAVY RAINFALL WILL BE PROBABLE IN SOME OF THESE STORMS AS THE PWATS ARE FORECAST TO BE AROUND 1.50 INCHES AND DEEP MOISTURE CONVERGENCE WILL BE ORIENTED PARALLEL TO THE UPPER FLOW. THIS PLUME WILL SHIFT EASTWARD THROUGH TUESDAY MORNING AND LIKELY POPS CERTAINLY SEEM JUSTIFIED TUESDAY MORNING. IF THE FRONT IS SLOW ENOUGH SOME AFTERNOON ENHANCEMENT OF A FEW STORMS COULD HAPPEN IN THE EAST...BUT THIS SEEMS MOST FAVORED EAST OF THE FORECAST AREA AT THIS TIME. THE COLD AIR ADVECTION WITH THE COLD FRONT...ALONG WITH POTENTIALLY SOME ANAFRONTAL SHOWERS...WILL LIKELY LEAD TO FALLING TEMPS IN SOME PLACES AT LEAST AT TIMES ON TUESDAY. WEDNESDAY AND BEYOND... LITTLE CHANGES MADE TO THIS PART OF THE FORECAST DUE TO ONGOING HIGHER IMPACT WEATHER. LARGE MODEL DIFFERENCES EXIST IN THE WED-THU TIME FRAME...WITH THE 12Z EC COMING IN SLOWER AND MORE AGGRESSIVE WITH A LOW RIDING UP THE BAROCLINIC ZONE TO OUR EAST. THIS PROVIDES WIDESPREAD SHOWERS WEDNESDAY AFTERNOON THROUGH EARLY THURSDAY AND PARTICULARY COOL TEMPS. WITH AN EC/GFS/GOING FORECAST BLEND THIS PROVIDES A FEW PERIODS OF CHANCE POPS. TEMPS TO LOOK TO BE BELOW NORMAL NO MATTER WHICH MODEL VERIFIES IN THE WED-FRI TIME FRAME. IF CONDITIONS CLEAR AND SURFACE RIDGING MOVES OVER...POSSIBLY THU NIGHT...THERE PROBABLY WILL BE A CONCERN FOR FROST. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * POSSIBLE MVFR CIGS EARLY THIS MORNING. * GUSTY SOUTHERLY WINDS TODAY. * TIMING AND CHANCES OF ADDITIONAL TSRA TODAY AND TONIGHT. KJB //DISCUSSION...UPDATED 06Z... CHANCES AND TIMING OF ADDITIONAL CONVECTIVE ACTIVITY WILL BE THE PRIMARILY WEATHER CONCERN ACROSS THE NORTHERN ILLINOIS TERMINALS AGAIN TODAY AND TONIGHT. UNFORTUNATELY...CONFIDENCE IS LOW ON ANY CONVECTIVE ACTIVITY MATERIALIZING ACROSS THE EASTERN TERMINALS TODAY...AND FOR THIS REASON...THE FORECAST REMAINS DRY FOR THE AREA. THE MAIN ATTENTION EARLY THIS MORNING IS OUT WEST ACROSS CENTRAL IOWA...WHERE A COMPLEX OF THUNDERSTORMS IS MOVING EASTWARD. THIS ACTIVITY COULD IMPACT THE TERMINALS LATER THIS MORNING IF IT HOLDS TOGETHER. HOWEVER...CONFIDENCE ON THIS MAKING IT TO THE EASTERN TERMINALS BEFORE WEAKENING...IS TOO LOW TO INCLUDE A MENTION IN THE TAF. TRAJECTORIES FOR THE STORM MOTIONS TEND TO SUPPORT AN EAST-NORTHEASTERLY MOVEMENT OF THROUGH THE EARLY MORNING HOURS...SO I HAVE INCLUDED THE MENTION OF A VCTS IN THE KRFD TAF AFTER 10 UTC THIS MORNING...TO ACCOUNT FOR ANY OF THE REMNANTS OF THIS ACTIVITY POSSIBLY IMPACTING THE TERMINAL. THE WINDS SHOULD BECOME SOUTHERLY TOWARDS DAYBREAK WITH THE SURFACE WARM FRONT STILL EXPECTED TO LIFT NORTH OF THE AREA. AS THIS OCCURS...IT IS POSSIBLE THAT A FEW LOW CLOUDS OR A BRIEF PERIOD OF LOWER CIGS COULD DEVELOP TOWARDS DAYBREAK AS LOWER LEVEL MOISTURE CONTINUES TO STREAM NORTHWARD OVER THE AREA. I CONTINUED THE MENTION OF SOME SCT015 CLOUDS IN THE GOING TAF. THERE IS A SMALL THREAT FOR AN MVFR CIG AROUND 1500 FEET TO DEVELOP FOR A BRIEF PERIOD THIS MORNING...BUT ANY LOWER CIGS SHOULD IMPROVE SHORTLY AFTER DAYBREAK TODAY. THE THREAT FOR CONVECTIVE ACTIVITY OVER OR NEAR THE TERMINALS THROUGH THE DAY TODAY APPEARS LOW...BUT NOT ZERO. IT APPEARS THAT ANY ACTIVITY...IF IT WERE TO DEVELOP ACROSS THE AREA...WOULD BE OF FAIRLY LOW AREAL COVERAGE DUE THE LACK OF ANY SIGNIFICANT TRIGGER MECHANISM ACROSS THE AREA. THERE ARE ALSO SOME CONCERNS ABOUT THE POSSIBILITY OF HIGHER LEVEL CLOUD DEBRIS...FROM THE OVERNIGHT STORMS...LINGERING OVER THE AREA TODAY AND LIMITING THE THREAT FOR ADDITIONAL DEVELOPMENT. THE NEXT MAIN THREAT FOR A PERIOD OF POSSIBLY MORE WIDESPREAD SHOWERS AND STORMS WILL LIKELY BE EITHER LATE MONDAY NIGHT OR EARLY TUESDAY AHEAD OF AN APPROACHING COLD FRONT. KJB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW FOR MVFR CIGS OVERNIGHT/EARLY MORNING. * LOW FOR TSRA DURING THE DAY TODAY. KJB //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... * TUESDAY...TSRA LIKELY IN THE MORNING. * WEDNESDAY...CHANCE OF SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY...DRY/VFR. && .MARINE... 242 PM...LOW PRESSURE OVER KANSAS WILL MOVE NORTHEAST TO LAKE SUPERIOR TUESDAY MORNING. AS IT DOES...A WARM FRONT EXTENDING EAST FROM THE LOW WILL MOVE NORTH ACROSS THE LAKE TONIGHT THROUGH MONDAY NIGHT...SHIFTING EASTERLY WINDS SOUTHERLY. LOW LEVEL MOISTURE WILL ALSO BE INCREASING AND AS IT SPREADS ACROSS THE COOLER LAKE...AREAS OF FOG ARE POSSIBLE AND SOME OF THE FOG MAY BECOME DENSE. CURRENT WIND SPEEDS ARE FAIRLY LIGHT IN THE 5-15 KT RANGE AND WILL INCREASE INTO THE 15-25KT RANGE AND REMAIN THERE UNTIL A COLD FRONT MOVES ACROSS THE LAKE TUESDAY MORNING. THERE IS A POTENTIAL FOR WINDS TO BE A BIT STRONGER ON MONDAY...ESPECIALLY WITH THE EASTERLY FLOW NORTH OF THE WARM FRONT ACROSS NORTHERN LAKE MICHIGAN. THERE REMAINS UNCERTAINTY REGARDING THE POTENTIAL FOR STRONG NORTHERLY WINDS WEDNESDAY NIGHT INTO THURSDAY AS LOW PRESSURE DEEPENS MOVING NORTH ACROSS THE GREAT LAKES REGION. THIS TIME PERIOD WILL NEED TO BE MONITORED FOR HIGHER NORTHERLY WIND SPEEDS. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1118 PM CDT Sun May 11 2014 .DISCUSSION... ISSUED 927 PM CDT Sun May 11 2014 The rest of WW #144 will be let go at 10 pm CDT. Most of the stronger storms have shifted off to our east with some lingering showers over north central McLean county. Large bow echo over western Iowa tracking east northeast at 45 to 50 mph. Latest HRRR model suggest what is left of the complex may get into western IL just before 12z. Will continue to keep low chance POPs across the north with the remainder of the area expecting to see dry conditions. Overall, the grids are in good shape. Will update the ZFP once our watch expires at 10 pm. && .AVIATION... ISSUED 1115 PM CDT Sun May 11 2014 Main concern will be with the potential for convection, currently over central Iowa, to make it into at least our northern TAF sites by morning. Based on the current movement of the large complex of storms over central Iowa, have decided to add a VCTS group to PIA and BMI between 11z and 14z. Until then, VFR conditions will continue. We should see VFR cigs during the day on Monday with any early morning showers out of the way by 16z or 17z. Then we will wait for more storms along a cold front to move in after 23z from west to east Monday evening. Confidence on coverage not very high this far out for convection so will just include a VCTS group for each site starting out west around 00z with the potential reaching our eastern counties by 03z. Surface winds will be from a 130-160 direction tonight and then turn more southerly on Monday with speeds tonight in the 8 to 13 kt range and then increase in speed to between 12 to 17 kts on Monday with gusts up to 25 kts at times by late morning into the afternoon hours. Smith && .PREV DISCUSSION... ISSUED 248 PM CDT Sun May 11 2014 Air mass destabilizing quickly across central and southeast Illinois early this afternoon. 18Z upper air sounding from our office showing CAPE of around 2600 J/kg with no convective inhibition, although shear values are not especially impressive. Latest SPC mesoanalysis indicates CAPE`s are over 3000 J/kg south of I-72, as dew points of 70 degrees have made it as far north as Taylorville. Warm front extends from southern Nebraska along the Iowa/Missouri border, but becomes more diffuse in northern Illinois where it is more of a dew point discontinuity. Thunderstorms have been percolating most of the day across the Ohio Valley, and a persistent, small MCS is advancing across Iowa. Some development has recently started as well across northeast Missouri south of the main MCS. Has been quiet in our area the last few hours, but latest radar returns are starting to show thunderstorms developing between Taylorville and St Louis. The primary forecast concern remains with the severe weather threat over the next 24 to 36 hours. SHORT TERM...Tonight through Tuesday: Latest runs of the HRRR have been persistent with the Iowa storms affecting more of the northern third of Illinois, with more scattered strong/severe storms affecting our area through about 7 pm. Shear parameters don`t really improve any in our area, so thinking that hail/wind threat will be the primary concerns here with the tornado threat closer to the warm front. After sunset, capping of the atmosphere will begin in the warm sector. Have maintained some 30-40% PoP`s after midnight northwest of the Illinois River, and slight chances as far east as I-55, with dry conditions across the southeast half of the forecast area. Similar convective parameters expected on Monday, with CAPE`s rising to 2500-3000 J/kg, although shear remains on the low side. Day2 slight risk basically along and northwest of the Illinois River, where the shear will be a bit higher as it is closer to the incoming cold front, and severe weather threat will mainly be mid afternoon to early evening. With the front slowing down a tad, will keep any PoP`s east of I-57 around 20% during the day, while likely PoP`s around 60% found during the afternoon along/west of the Illinois River. Have maintained the 60-70% PoP`s everywhere during the night as the front slowly moves through, and over the eastern CWA on Tuesday with some 80% values south of I-70 Tuesday. Severe weather threat on Tuesday appears minimal, and would be near the Indiana border if any did occur. LONG TERM...Wednesday through Sunday: A broad upper trough will be dominating much of the eastern half of the nation into the first part of the weekend, with cool conditions prevailing. The ECMWF has been persistent with a closed upper low forming by late Thursday over the Great Lakes, then lifting northward, while the GFS keeps a more progressive trough. Toward the end of the weekend, the trough will finally start to break down as an upper low digs southward across the Pacific Northwest, causing rising heights over the center of the nation. Most challenging area in this forecast period is with rain on Wednesday. The tail end of the NAM is trending toward the solution favored by the ECMWF and GEM for the last few days, with a surface low riding northeast along the base of the trough, although the NAM is much further west with it. The GFS has keep its surface features much weaker and further east. Have kept the likely PoP`s on Wednesday across the southeast third of the area, although the ECMWF/GEM solutions would likely require this to be expanded further northwest toward the I-55 corridor. Thursday and Friday, the rain will be much more scattered in nature, as weak troughs rotate around through the broad upper trough. Rain chances will diminish this weekend as the upper flow flattens. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 AM CDT MON MAY 12 2014 .SYNOPSIS... ISSUED AT 321 AM CDT MON MAY 12 2014 LOW PRESSURE MOVING INTO WESTERN IA WILL LIFT NORTHEAST AS COLD FRONT SWEEPS ACROSS THE STATE BY LATE TONIGHT. PATTERN WILL CHANGE TO A MUCH COOLER REGIME AS CANADIAN HIGH PRESSURE DOMINATES THROUGH THE REST OF THE WORK WEEK. && .SHORT TERM /TODAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 TWO PROBLEMS TODAY ARE BOTH WITH CONVECTION THE EARLY MORNING CONVECTION WILL BE AN ISSUE WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL MOVING INTO ALREADY SATURATED AREAS. THIS IS ASSOCIATED WITH A WEAK WAVE IN THE FLOW THAT IS LIFTING NORTHEAST ACROSS THE STATE. ADDITIONAL DEVELOPMENT IS LIKELY OVER THE SOUTHEAST HALF OF THE STATE WITH THE COLD FRONT PROGRESSING EAST. THE HRRR HAS WHAT SEEMS TO BE A REASONABLE HANDLE ON THIS. SEVERITY WILL DEPEND ON HOW MUCH RECOVERY WE CAN ACHIEVE AFTER THE MORNING CONVECTION. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 PRECIPITATION WILL MOVE OUT OF THE STATE BY 06Z AS THE PATTERN CHANGES FROM A SOUTHWEST FLOW TO A NORTHWEST FLOW. CANADIAN HIGH PRESSURE WILL DOMINATE THE WEEKS WEATHER WITH TEMPERATURES WELL BELOW NORMAL. WILL POTENTIAL NEED TO CONSIDER SOME FROST WORDING LATER IN THE WEEK, BUT CERTAINTY IS NOT THERE AT THIS TIME BECAUSE OF THE POTENTIAL FOR SOME CLOUD COVER. IT WILL LIKELY TAKE UNTIL THE WEEKEND BEFORE THE COOL HIGH PRESSURE MOVES OFF TO THE EAST. WARMING AND AN INCREASED CHANCE FOR THUNDERSTORMS IS EXPECTED LATER IN THE WEEKEND. && .AVIATION...12/06Z ISSUED AT 1249 AM CDT MON MAY 12 2014 THUNDERSTORMS WILL REMAIN POSSIBLE OVERNIGHT ESPECIALLY OVER THE SOUTHEAST SITES. GUSTY WINDS FROM THE WEST TO SOUTHWEST ARE POSSIBLE WITH STORM OUTFLOW ALONG WITH GREATLY REDUCED VSBYS WITH HEAVY RAINFALL. THE PRECIPITATION SHOULD DIMINISH EARLY MONDAY MORNING BEFORE INCREASING AGAIN LATE MORNING AND INTO THE AFTERNOON. MVFR CIGS ARE EXPECTED TO DEVELOP MONDAY. A FRONTAL BOUNDARY WILL ARRIVE LATE WITH A SWITCH TO WESTERLY WINDS. && .HYDROLOGY... ISSUED AT 321 AM CDT MON MAY 12 2014 THEN ENVIRONMENT REMAINS FAVORABLE FOR HEAVY RAINFALL AT LEAST THROUGH EARLY THIS MORNING WITH THE LOW PRESSURE AND COLD FRONT CLOSE. DECENT DEVELOPMENT OVER WESTERN IOWA AND TO THE SOUTHWEST OF THE STATE WILL MOVE NORTHEAST THROUGH THE STATE THIS MORNING. MOST VULNERABLE AREAS WILL BE THE SOUTHWEST AND SOUTH CENTRAL AREAS...AND SOME IN THE NORTHWEST...WHERE RAINFALL TOTALS HAVE BEEN IN THE 2 TO 3 INCH RAIN LOCALLY WITH SOME HIGHER TOTALS. ADDITIONAL THUNDERSTORM DEVELOPMENT LATER IN THE DAY IS LIKELY TO BE EAST OF THESE AREAS AND TO NOW ANTICIPATE EXTENDING THE FLASH FLOOD WATCH AT THIS TIME. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR ADAIR-ADAMS- AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-CASS- CERRO GORDO-CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GRUNDY-GUTHRIE- HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-MADISON-MARSHALL-PALO ALTO-POCAHONTAS-POLK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-UNION- WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SYNOPSIS...MS MAY 14 SHORT TERM...MS MAY 14 LONG TERM...MS MAY 14 AVIATION...DONAVON HYDROLOGY...MS MAY 14
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 PM CDT SUN MAY 11 2014 .UPDATE... ISSUED AT 635 PM CDT SUN MAY 11 2014 DATA TRENDS THE PAST 3 HOURS NOW INDICATE THERE WILL BE A BREAK IN ACTIVITY DURING THE EVENING HOURS. THE CURRENT THUNDERSTORM COMPLEX IS SLOWLY MOVING INTO NORTHEAST ILLINOIS BUT BOUNDARIES LEFT OVER WILL ALLOW STORMS TO PERSIST OVER THE SOUTHERN PARTS OF THE AREA FOR THE NEXT SEVERAL HOURS. AN EFFECTIVE BOUNDARY IS EVIDENT ACROSS SOUTHERN IOWA WITH NO CELLULAR CLOUDS NORTH OF THE BOUNDARY AND DIURNAL CLOUDS ACROSS MISSOURI. THIS BOUNDARY MAY PROVIDE A FOCUS FOR ADDITIONAL ISOLATED TO SCATTERED STORMS THROUGH SUNSET. DATA STILL SUGGESTS THE STORMS IN NEBRASKA WILL EVOLVE INTO A NEW THUNDERSTORM COMPLEX ACROSS WESTERN IOWA THIS EVENING IN THE BETTER FORCING AND SLOWLY MOVE EASTWARD WITH ACTIVITY ENTERING THE NORTHWEST HALF OF THE AREA AFTER MIDNIGHT. && .SYNOPSIS... ISSUED AT 356 PM CDT SUN MAY 11 2014 12Z UA ANALYSIS HAS 850MB LOWS IN NORTHWEST MINNESOTA WITH A STRONG 850MB LOW IN WESTERN KANSAS. AN 850MB WARM FRONT RAN FROM THE KANSAS LOW INTO SOUTHERN IOWA. A STRONG LLJ RAN FROM THE GULF COAST INTO THE CENTRAL PLAINS. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON HAS CONVECTION ACROSS EASTERN IOWA AND NORTHERN ILLINOIS WITH NEW CONVECTION DEVELOPING IN THE PLAINS. 18Z SFC ANALYSIS HAS A WEAK LOW IN WESTERN WISCONSIN WITH A DEVELOPING WARM FRONT SOUTHEAST INTO CENTRAL LAKE MICHIGAN. AN IMPLIED LOW WAS IN SOUTHERN IOWA APPROACHING KOTM WITH ANOTHER LOW IN WESTERN KANSAS. A FRONTAL BOUNDARY RAN FROM THE KANSAS LOW INTO THE IOWA LOW NEAR KOTM WITH A WARM FRONT FROM NEAR KOTM NORTHEAST TO THE WISCONSIN/ILLINOIS BORDER. DEW POINTS SOUTH OF THE FRONT WERE IN THE 60S WITH 40S AND 50S IN THE NORTHERN PLAINS INTO THE GREAT LAKES NORTH OF THE FRONT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 356 PM CDT SUN MAY 11 2014 BOUNDARIES FROM THE NOCTURNAL THUNDERSTORM COMPLEX INITIATED A NEW STORM COMPLEX ALONG THE WARM FRONT IN SOUTHERN IOWA THIS MORNING. THIS NEW STORM COMPLEX MOVED EAST NORTHEAST AND IS SLOWLY DECAYING ACROSS THE AREA. HOWEVER...BOUNDARIES FROM THIS STORM ALONG WITH DIURNAL HEATING HAS INITIATED NEW DISCRETE STRONG TO SEVERE STORMS THAT WILL CONTINUE THROUGH LATE AFTERNOON. BASED ON SATELLITE...RADAR...AND RAP TRENDS...THERE MAY BE A BREAK IN STORM ACTIVITY THIS EVENING AS THE NEW SEVERE STORMS CONTINUE TO DEVELOP AND MOVE NORTHEAST WELL WEST OF THE AREA. AFTER MIDNIGHT THE STORMS OUT WEST WILL EVOLVE UPSCALE INTO ANOTHER NOCTURNAL THUNDERSTORM COMPLEX THAT WILL SLOWLY MOVE INTO THE NORTHWEST THIRD OF THE AREA. ISOLATED TO SCATTERED STORMS ARE VERY POSSIBLE AHEAD OF THIS STORM COMPLEX AS MOISTURE CONTINUES TO FEED INTO THE AREA. ON MONDAY THE BETTER RAIN CHANCES WILL BE OVER THE NORTHWEST HALF OF THE AREA DURING THE MORNING. DURING THE AFTERNOON...NEW CONVECTION IS EXPECTED TO DEVELOP AS ANOTHER DISTURBANCE ALOFT MOVES THROUGH THE AREA. BASED ON THE POSITION OF THE MAIN FEATURES AND OVERALL EXPECTED FORCING...SEVERE STORMS ARE POSSIBLE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 356 PM CDT SUN MAY 11 2014 MONDAY NIGHT THE MAIN COLD FRONT BEGINS MOVING THROUGH THE AREA. CONVECTION IS EXPECTED TO BE WIDESPREAD AND MAY EVOLVE INTO A BAND OF STRONG STORMS DURING THE EVENING HOURS. IF A BAND DOES FORM IT WILL SLOWLY MOVE EAST OVERNIGHT. ON TUESDAY...RAIN WILL END FROM WEST TO EAST DURING THE DAY WITH MOST OF THE AREA BEING DRY BY MID DAY. TEMPERATURES WILL BE WELL BELOW NORMAL. HIGH PRESSURE MOVING THROUGH THE MIDWEST TUESDAY NIGHT WILL RESULT IN DRY CONDITIONS WITH SEASONABLY COOL TEMPERATURES. ON WEDNESDAY THE NEXT STORM SYSTEM MOVES NORTHEAST FROM THE SOUTHERN PLAINS INTO THE OHIO VALLEY. THE TRENDS WITH THE MODELS HAVE BEEN TO SLOWLY PULL THE STORM SYSTEM TO THE NORTH AND WEST. WEDNESDAY NIGHT ON... THERE CONTINUES TO BE DIFFERENCES BETWEEN THE GLOBAL MODELS AS TO WHAT WILL OCCUR...BUT...ALL AGREE THAT TEMPERATURES WILL AVERAGE BELOW NORMAL WEDNESDAY NIGHT THROUGH SUNDAY. WEDNESDAY NIGHT/THURSDAY THE MODEL CONSENSUS HAS SLIGHT CHANCE TO CHANCE POPS AS THE NEXT SYSTEM MOVES UP THROUGH THE OHIO VALLEY. THE TREND IN THE MODELS HAS BEEN TO SLOWLY BRING THE STORM FURTHER TO THE NORTH AND WEST. THE MODEL CONSENSUS HAS MAINLY DRY CONDITIONS THURSDAY NIGHT AS THE STORM SYSTEM EXITS THE AREA. FRIDAY THROUGH SATURDAY THE MODEL CONSENSUS HAS MAINLY SLIGHT CHANCE POPS FRIDAY AND SATURDAY WITH MAINLY DRY CONDITIONS FRIDAY NIGHT. DISTURBANCES WILL CONTINUE TO ROTATE AROUND THE UPPER LOW OVER THE GREAT LAKES PRODUCING MAINLY DIURNAL SHOWERS. IF ENOUGH CLEARING CAN TAKE PLACE FRIDAY NIGHT AND WINDS REMAIN LIGHT...THERE MAY BE A POTENTIAL FOR FROST. DRY CONDITIONS SHOULD BE SEEN SATURDAY NIGHT AS HIGH PRESSURE MOVES THROUGH THE AREA. ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO CHANCE POPS FOR ROUGHLY THE WESTERN HALF OF THE AREA AS THE NEXT STORM SYSTEM MOVES EAST FROM THE PLAINS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1133 PM CDT SUN MAY 11 2014 A LARGE...BUT PROGRESSIVELY MORE LOOSELY ORGANIZED COMPLEX OF STORMS WILL SPREAD EAST FROM CENTRAL IOWA INTO EASTERN IOWA AND NORTHWEST ILLINOIS THE REST OF TONIGHT. THIS MAY BRING SOME GUSTY WINDS...ESPECIALLY TO NORTHEAST IOWA. VFR CONDITIONS WILL DROP TO MVFR/HIGHER IFR AT TIMES IN ANY STORM. MONDAY WILL CONTINUE TO SEE A RISK FOR SHOWERS AND STORMS...MOST WIDESPREAD IN THE LATE AFTERNOON AND EVENING HOURS. AT THAT TIME...ANOTHER ROUND OF POTENTIAL MVFR/IFR IS LIKELY IN STORMS. WINDS WILL BE SOUTH TO SOUTHEAST AROUND 10 KTS THROUGH THE PERIOD. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...08 SHORT TERM...08 LONG TERM...08 AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1215 AM CDT Mon May 12 2014 ...UPDATE TO AVIATION... .SYNOPSIS... ISSUED AT 1007 PM CDT SUN MAY 11 2014 Water vapor imagery and 00Z upper air analysis indicate a strong closed off upper level low shifting eastward across the Four Corners Region. A +70kt upper level jet is lifting northeast across western Kansas. Near the surface, a strong cold front extending from northeastern Kansas southwest into the Oklahoma panhandle, is pushing southeast across central Kansas. Much colder and drier air is spilling southward into western Kansas with surface dewpoints dropping mainly into the 40s(F) with a few 30s(F) out near the Colorado border. && .SHORT TERM...(This evening through Monday) ISSUED AT 254 PM CDT SUN MAY 11 2014 Abbreviated AFD due to ongoing warning operations. From my mesoscale discussion at 1:53 PM... (Convection already has developed by the same mesoscale assessments still applies) Special 18Z KDDC raob shows just a little bit of CIN remaining. Won`t be long before convection develops. Visible satellite imagery shows increasing cumulus along the dryline/front. HRRR indicates thunderstorms developing along the Highway 283 corridor in the 3-4 pm time range. Right moving Bunkers shows propagation vectors northeasterly at 45 kt. Initial threat will be large hail (up to 20! on the LHP using NAM thermodynamic and kinematic variables) and damaging outflow winds. There is an small window of tornadic opportunity between 7 and 9 pm as low level winds back across central/south central-Kansas but all the big wedge/strong tornadoes should remain across Nebraska/Iowa with just small spin ups/weak tornadoes in our area, if possible. Convection will depart the area tonight. Some light showers will be possible on the backside of the departing wave. It will be windy post frontal through tomorrow. Right now conditions look borderline for wind advisory criteria. .LONG TERM...(Monday night through Sunday) ISSUED AT 122 PM CDT SUN MAY 11 2014 An upper level longwave trough will be moving across the Plains on Tuesday but should be dry with the moisture pushed east of the area. Colder temperatures will accompany this trough with overnight lows on Monday night into the mid 30s and highs on Tuesday in the low to mid 60s. Strong northwest winds will mix down to the surface with winds of 15 to 30 mph and partly cloudy skies. For Wednesday into Thursday, dry northwesterly upper level flow will follow with highs slowly warming into the upper 60s and 70s. Wednesday morning may be the coldest morning with light winds and lows in the low to mid 30s. For Friday and Saturday, a few showers and thunderstorms may form as as some upper air disturbances in northwest flow aloft interact with increasing upslope moisture. Lows will be in the 40s and highs around 70 to 75. On Sunday, of next week, upper level ridging is forecast with dry and warmer temps around 80. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) ISSUED AT 1215 AM CDT MON MAY 12 2014 MVFR/IFR cigs will prevail at all TAF sites through early this afternoon as low level stratus developing behind the exiting cold front persists across central and southwest Kansas. The cigs will continue to lift through the afternoon with VFR returning by Monday evening. As for winds, surface high pressure across the Northern Rockies will build southeast into the Colorado Rockies today. As a result, northwesterly winds of around 15 to 30kt will persist through Monday afternoon. && .PRELIMINARY POINT TEMPS/POPS... DDC 35 63 37 69 / 0 0 0 0 GCK 34 62 37 68 / 0 0 0 0 EHA 34 61 35 68 / 0 10 0 0 LBL 34 62 36 70 / 0 10 0 0 HYS 35 63 38 69 / 0 0 0 0 P28 40 66 42 70 / 0 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY until 1 AM CDT /Midnight MDT/ early this morning FOR KSZ030-031-043>046-061>066-074>081-084>090. && $$ SYNOPSIS...JJohnson SHORT TERM...Sugden LONG TERM...Kruse AVIATION...JJohnson
AREA FORECAST DISCUSSION
NWS JACKSON KY
215 AM EDT MON MAY 12 2014 .UPDATE... ISSUED AT 215 AM EDT MON MAY 12 2014 A FEW SHOWERS HAVE DEVELOPED OVER THE NE PART OF THE FORECAST AREA. THE HRRR MODEL HAS THIS IN HAND...AND IS SHOWING THE PRECIP HEADING OUT TO THE EAST OVERNIGHT. HAVE UPDATED TO INCLUDE A SLIGHT CHANCE OF PRECIP IN THAT AREA FOR A SHORT TIME OVERNIGHT. UPDATE ISSUED AT 1109 PM EDT SUN MAY 11 2014 THE FORECAST REMAINS ON TRACK TONIGHT. SOME OF THE MORE SHELTERED VALLEYS HAVE DROPPED OFF INTO THE MID 60S...SO A FEW UPPER 50S STILL LOOK ACHIEVABLE. THICKER HIGH CLOUD BLOW OFF FROM EARLIER CONVECTION IS ALSO THINNING ACROSS THE NORTHERN HALF OF THE AREA...SO WILL MAINTAIN PARTLY CLOUDY SKIES NORTH AND MOSTLY CLEAR SKY CONDITIONS SOUTH...BESIDES A FEW PATCHES OF MID-LEVEL CLOUDS DEVELOPING FROM TIME TO TIME. FRESHENED UP THE HOURLY SKY COVER...TEMPERATURES...AND DEW POINTS ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 301 PM EDT SUN MAY 11 2014 FAIRLY QUIET PATTERN IN STORE FOR EASTERN KENTUCKY THROUGH TUESDAY MORNING. A RIDGE OF HIGH PRESSURE SHOULD KEEP THINGS HIGH AND DRY OVERNIGHT INTO EARLY MONDAY MORNING. THE MODEL DATA IS ALL SUGGESTING THAT JUST ENOUGH INSTABILITY AND LOW LEVEL MOISTURE WILL BE AVAILABLE TO SPARK SHOWER AND THUNDERSTORMS ACROSS THE AREA...WITH THE AFTERNOON PEAK HEATING HOURS PREFERRED. THE LATEST MOS GUIDANCE AND MODEL TIME HEIGHTS AND SOUNDINGS ALSO SUGGEST THIS POSSIBILITY. WITH THE MODELS ALL SHOWING FAIRLY SIMILAR SOLUTIONS FOR THE AREA FROM LATE TONIGHT THROUGH TUESDAY MORNING...THE NAM12 SOLUTION SEEMED AS GOOD AS ANY FOR THIS GO ROUND. IN SPITE OF A GOOD DEAL OF SHOWER AND STORM ACTIVITY ONGOING ACROSS CENTRAL AND WESTERN KENTUCKY AND SOUTHERN INDIANA...IT APPEARS THAT IT WILL BE TOO DRY SHOWERS OR STORMS TO FORM ACROSS EASTERN KENTUCKY TODAY AND TONIGHT. THEREFORE...THE NEW FORECAST WILL FEATURE A DRY OVERNIGHT PERIOD...WITH ISOLATED SHOWERS AND STORMS BEGINNING TO FIRE UP BETWEEN 16 AND 17Z ON MONDAY. ONCE THE SUN BEGINS TO SET AND HEATING IS LOST...ANY EXISTING SHOWERS OR STORMS WILL DISSIPATE QUICKLY LATE TOMORROW AFTERNOON. MONDAY NIGHT AND TUESDAY LOOK TO BE WARM AND DRY AS HIGH PRESSURE BUILDS WESTWARD AND KEEPS PRECIPITATION PUSHED OFF TO OUR WEST. TEMPERATURES WILL BE WELL ABOVE NORMAL THE NEXT COUPLE OF DAYS...WITH TOMORROWS HIGHS TOPPING OUT IN THE MID 80S AND LOWS ON MAKING IT INTO THE UPPER 50S AND LOWER 60S THE NEXT TWO NIGHTS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 425 PM EDT SUN MAY 11 2014 THE PERIOD WILL BEGIN WITH AN UPPER LEVEL RIDGE CENTERED OFF THE SOUTHEAST UNITED STATES WITH RIDGING NORTH INTO THE CENTRAL APPALACHIANS. ANOTHER RIDGE IS EXPECTED TO BE IN PLACE ALONG THE WEST COAST WITH A TROUGH EXPENDING FROM CENTRAL CANADA SOUTH INTO THE PLAINS AND SOUTHERN ROCKIES. BY THE START OF THE PERIOD...THE ECMWF IS QUICKER MOVING A SHORTWAVE TROUGH NEAR THE US/CANADIAN BORDER EAST AS IT IS WITH A MORE SOUTHERN SHORTWAVE WORKING THROUGH THE ROCKIES. DOWNSTREAM OF THIS TROUGH THE ECMWF IS ALSO FURTHER WEST WITH THE TROUGH AXIS OVER THE EASTERN CONUS. THROUGH WED EVENING...THE TROUGH AXIS WILL GRADUALLY WORK EAST AND APPROACH THE MS VALLEY REGION AS THE AXIS OF THE RIDGE TO THE EAST MOVES OFF INTO THE ATLANTIC AND THE RIDGE AXIS MOVES ONTO THE US WEST COAST. AT THE SFC...A PARENT SFC LOW SHOULD TRACK WELL NORTH OF THE REGION INTO QUEBEC BY WED EVENING. THE TRAILING SFC COLD FRONT WILL ENTER THE COMMONWEALTH ON TUE AFTERNOON AND BEGIN TO BECOME STATIONARY AS IT NEAR THE MID AND UPPER OH VALLEY AND APPALACHIANS. A SFC WAVE IS PROGGED TO DEVELOP ALONG THE BOUNDARY TUE NIGHT AND TRACK INTO THE COMMONWEALTH BY WED EVENING. THE ECMWF CONTINUES TO BE DEEPER WITH THE INITIAL SOUTHERN ROCKIES SHORTWAVE AS IT MOVES TOWARD THE MID MS VALLEY REGION. THIS LEADS TO MODEL DIFFERENCES WITH A MORE WESTERN AND DEEPER SFC WAVE DEVELOPMENT TUE NIGHT INTO WED. THE SFC LOW SHOULD EVENTUALLY TRACK INTO THE GREAT LAKES REGION BY LATE WED NIGHT OR THU AND SEND THE COLD FRONT TO THE EAST OF THE REGION BY MIDDAY ON THU. DEEPER MOISTURE SHOULD ALSO DEPART TO THE EAST AT THAT TIME...BUT THE UPPER TROUGH AXIS WILL NOT WORK ACROSS THE AREA UNTIL FRIDAY. A WESTERN RIDGE AND EASTERN TROUGH IS EXPECTED TO START THE WEEKEND...WITH THE RIDGE AXIS WORKING INTO THE PLAINS BY THE END OF THE PERIOD AND AT THAT TIME...THE TROUGH AXIS SHOULD MOVE TOWARD THE EASTERN SEABOARD. CONVECTION CHANCES WILL SOMEWHAT DIURNALLY DRIVEN EARLY IN THE PERIOD...BUT AS THE SFC FRONT APPROACHES LATE TUE NIGHT AND WED MOISTURE WILL INCREASE AND A WEAK LEAD SHORTWAVE MAY APPROACH FROM THE SOUTHWEST. HOWEVER...AS THE MAIN SHORTWAVE APPROACHES AND THE SFC WAVE TRACKS THROUGH THE OH VALLEY LATER WED INTO THU AM...CONVECTION CHANCES WILL BE BEST. UNSETTLED WEATHER WILL STILL REMAIN POSSIBLE INTO THE START OF THE WEEKEND...BEFORE THE TROUGH AXIS MOVES TO THE EAST. TEMPERATURES WILL BEGIN THE PERIOD ABOVE NORMAL...BUT BELOW NORMAL TEMPERATURES...AVERAGE ABOUT 10 OR MORE DEGREES BELOW NORMAL ARE EXPECTED BEHIND THE FRONT...FROM THU INTO SUN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 215 AM EDT MON MAY 12 2014 A FEW SHOWERS WERE OCCURRING OVER THE NE PART OF THE FORECAST AREA AT THE START OF THE PERIOD. THEY SHOULD MOVE OUT BEFORE DAWN...AND PROVIDE LITTLE IN THE WAY OF CEILING/VISIBILITY RESTRICTIONS. HOWEVER...FOG WILL AFFECT THE DEEPER VALLEYS IN EASTERN KY WITH LOCALIZED VISIBILITY LESS THAN A MILE UNTIL SHORTLY PAST SUNRISE. THERE IS A POSSIBILITY OF SHOWERS POPPING UP DURING THE DAY ON MONDAY...AND A FEW THUNDERSTORMS CAN NOT BE RULED OUT. THE PROBABILITY AT ANY GIVEN LOCATION IS RATHER LOW...AND ONLY VCSH HAS BEEN USED IN TAFS. OUTSIDE OF HEAVIER SHOWERS...VFR IS ANTICIPATED THROUGH MOST OF THE DAY. WILL LOOK FOR ANY PRECIP TO DIE OUT TOWARD EVENING. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL/GEOGERIAN SHORT TERM...AR LONG TERM...JP AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1156 PM CDT Sun May 11 2014 .UPDATE... Issued at 1155 PM CDT SUN MAY 11 2014 The AVIATION section has been updated for the 06Z TAF issuance. UPDATE Issued at 930 PM CDT SUN MAY 11 2014 The likelihood of lightning strikes has dropped low enough this evening that there will be no mention of them in the HWO or the gridded products overnight. Despite ridging in the mid levels, the tepid lower trop is such that a stray light rain shower cannot be ruled out overnight, however. && .SHORT TERM...(Tonight through Tuesday night) Issued at 317 PM CDT SUN MAY 11 2014 Pockets of surface-based instability continue to expand over the WFO PAH CWA this afternoon, aided by decent insolation and weak to moderate directional shear (25-35 knots) aloft (as evidenced by the anvil rain plumes oriented from northwest to southeast). The old cold pool has eroded over southeast IL and southwest IN from the morning convection, so distinct theta-e gradients are in place. Given the GOES Water Vapor imagery, the moisture gradient aloft implies a gradient in lapse rates as well, helping to enhance updrafts. (This is evidenced by the newly organized storms with hail in Southeast IL). The 12km RUC also suggests that the expended CAPE along and north of the implied surface warm frontal reflection arcing from northwest to southeast through southeast Illinois into northwest Kentucky. Further expenditure of CAPE through 01z suggests that the pool of convective instability should drop markedly. In addition, model heights are expected to rise this evening with a subtle change in balance takes place between the eastern U.S. ridge and the center of the sharpening trough over Western Nebraska. Expect that rain chances will be essentially nil over the entire WFO PAH CWA by midnight, as the warm frontal boundary moves well north of the area and shear decreases with time. As mentioned in yesterday`s discussion, channeled vorticity along the eastern limb of the trough near the inflection point between the trough/ridge circulation (cyclonic/anticyclonic flow) will aid in creating some lift in advance of an approaching moisture plume from the Gulf of Mexico around daybreak on Monday. This transition zone for convection will move slowly east through Monday afternoon, as the main trough actually sharpens and becomes slightly negatively tilted west of Iowa and Missouri Monday night into Tuesday morning. By 09z (4 am CDT) Tuesday morning, the cold front associated with this trough is expected to move into western sections of the WFO PAH Forecast area (Southwest IL/Southeast MO). By late evening Monday and into early Tuesday, the coverage of showers and thunderstorms should pick up significantly. It is at this time, that my concern for heavy rain potential will increase, with the potential for at least minor flooding by daybreak on Tuesday over parts of Southeast Missouri northeast to the Mississippi River. QPF values in excess of two inches would not be out of the question during that time period. The 12km NAM-WRF is actually suggesting a new closed circulation will develop at the based of the mean trough over the upper Midwest, somewhere near the OK/TX panhandles by Tuesday night, moving into southern Missouri by Wednesday evening. This is similar to what the ECMWF advertised in the Friday/Saturday model runs. This will lead to enhanced precipitation, both pre/post frontal as the frontal boundary remains fixed along the Interstate 57/55 corridor in Southern IL/Southeast Missouri. Most of the upright (thunderstorm) instability may be mixed out by Tuesday afternoon and night, but warm top (satellite reference) convection processes will likely take over increasing the effectiveness of the rainfall from Tuesday into Wednesday. There is still some question with respect to severe potential during this time period, but heavy rainfall still remains the dominant threat Tuesday into Wednesday. .LONG TERM...(Wednesday through Sunday) Issued at 417 PM CDT SUN MAY 11 2014 Confidence is fairly high concerning the general synoptic pattern in the Wed-Sun time frame. It is looking more and more like a high amplitude mid level trof will be carved out from southeast Canada southward all the way into the Ms River Valley by the Wed/Thu period. On east side of the trof, broad swly flow aloft will be evident. As a sfc low lifts ne along the spine of the Appalachians Wed, it appears showers will once again overspread most of the forecast area. Highest rain amounts will probably be over wrn KY and sw IN. Once the sfc low pulls off to the northeast Wed night, and the h50 trof axis moves east of the region, rain chcs should decrease considerably for much of the remainder of the extended. However, very low height fields and extensive daytime cloudiness behind the system will likely lead to an extended period of below normal temperatures. Highs are only expected to reach the 60s most locations Thu/Fri/Sat. && .AVIATION... Issued at 1155 PM CDT SUN MAY 11 2014 The latest guidance seems to be trending wetter for Monday, but figure with the entire area in the warm sector, diurnal convection will be very sparse in coverage. Kept the TAFs dry for the entire period. South southwest winds should gust 20-25kts for much of the day. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS SHORT TERM...Smith LONG TERM...GM AVIATION...DRS
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1135 PM CDT SUN MAY 11 2014 .AVIATION... FOR THE 12/06Z TAF ISSUE...EXPECT MVFR CIGS TO CONTINUE SPREADING NORTHWARD INTO EAST TEXAS AND WESTERN LOUISIANA. ISOLATED SHWRS AND TSTMS WILL ALSO BE ONGOING IN THE EAST TEXAS LAKES AREA AS WELL AS NORTH CENTRAL LOUISIANA. BY 09Z AND CONTINUING UNTIL 14Z...IFR CIGS BETWEEN 5 HUNDRED AND 1 KFT WILL BE COMMON ACROSS THE REGION. LIGHT FOG WILL ACCOMPANY THE LOWER CIGS AT A FEW TERMINALS WITH VSBYS BETWEEN 3 AND 5 MILES. VFR SHOULD RETURN TO MOST LOCATIONS BETWEEN 15Z AND 16Z...WITH CIGS 3 TO 4 KFT. ISOLATED TSTMS WILL DEVELOP WITH AFTERNOON HEATING...BECOMING MORE NUMEROUS FROM SE OK INTO E TX AFTER 21Z. SURFACE WIND SOUTH TO SOUTHEAST 10 TO 15 KTS TONIGHT AND INTO MONDAY WITH GUSTS 20 TO 25 KTS AFTER 14Z. /14/ && .PREV DISCUSSION... /ISSUED 1028 PM CDT SUN MAY 11 2014/ DISCUSSION... INTERESTING FORECAST UPDATE FOR THE REMAINDER OF THE OVERNIGHT HOURS. CONVECTION ACROSS NATCHITOCHES PARISH HAS FINALLY DISSIPATED BUT RENEWED CONVECTION CONTINUES TO DEVELOP ACROSS DEEP EAST TEXAS AND SHOWS SIGNS OF EXPANDING NORTH AND WEST. THIS WOULD MAKE SENSE AS LATEST RUN OF THE HRRR SUGGESTS INCREASING CAPE OVERNIGHT ACROSS OUR WESTERN HALF. CONVECTION IS PROBABLY BEING AIDED BY A 50KT LOW LEVEL JET OFF SHV`S WSR-88D VAD WIND PROFILER. A QUICK LOOK AT ISENTROPIC SFCS NEAR OR SLIGHTLY ABOVE THE 930MB LEVEL SUGGEST A CONTINUATION OF ISENTROPIC LIFT WITH LOW CONDENSATION PRESSURE DEFICITS ACROSS OUR WESTERN HALF AS WELL. HAVING SAID ALL THIS...FOR THE UPDATE...WILL CONTINUE WITH A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE REMAINDER OF THE NIGHT ACROSS ALL ZONES...EVEN THOUGH I`M A LITTLE MORE CERTAIN OF THE BEST COVERAGE BEING ACROSS OUR WESTERN ZONES WHERE THE INSTABILITY OVERNIGHT WILL BE GREATER. TEMPERATURES AS OF 03Z ARE RUNNING A LITTLE WARMER THAN THIS TIME AND GIVEN THE QUICK RETURN TO THE LOW LEVEL CLOUD COVER ALREADY SEEN ON IR IMAGERY ALONG AND SOUTH OF A LFK...SHV...MLU LINE...ANOTHER WARM NIGHT IS IN STORE ACROSS THE REGION. HOURLY TEMPS ARE ALMOST DEAD ON WITH FCST HOURLY TEMPS AND OVERNIGHT MINS ARE FORECAST TO BE SOME 2 TO 3 DEGREES WARMER THAN LAST NIGHT. FOR THAT REASON...TEMPS APPEAR TO BE IN PRETTY GOOD SHAPE. EXPECTING SOUTHEAST WINDS NEAR 10 TO 15 MPH AREAWIDE WITH AN OCCASIONAL GUST FROM TIME TO TIME GIVEN THE STRONG PRESSURE GRADIENT IN THE LOWER LEVELS. ONLY UPDATE NECESSARY APPEAR TO BE AN EXTENSION TO THE POP FORECAST SPATIALLY BUT OTHERWISE...NO OTHER CHANGES ARE NECESSARY. FCST UPDATE OUT SHORTLY...13. && .PRELIMINARY POINT TEMPS/POPS... SHV 73 86 67 79 57 / 20 50 60 70 50 MLU 70 86 67 83 60 / 20 50 50 60 50 DEQ 71 82 60 70 51 / 20 60 80 70 50 TXK 71 83 62 72 54 / 20 60 80 70 50 ELD 70 84 66 78 55 / 20 50 60 70 50 TYR 73 84 61 70 52 / 20 60 80 60 50 GGG 73 85 65 74 54 / 20 50 80 70 50 LFK 73 87 69 79 55 / 20 50 60 70 50 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
516 AM EDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 515 AM EDT MON MAY 12 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A BUILDING RIDGE ALONG THE W COAST OF NAMERICA WITH AMPLIFIED DOWNSTREAM TROF OVER THE ROCKIES. MAIN PIECE OF ENERGY IS IN THE BASE OF THE TROF OVER COLORADO. WAA/ISENTROPIC ASCENT DOWNSTREAM INTO THE UPPER LAKES IS SUPPORTING A LARGE AREA OF SHRA/TSRA LIFTING NE ACROSS MN/WI EARLY THIS MORNING. SHORTWAVE MOVING NE INTO WRN WI IS FURTHER AIDING THE PCPN. INSTABILITY HAS BEEN SLOW TO ADVANCE N PER SPC MESOANALYIS...SO WHILE SHRA ARE ADVANCING STEADILY N AND E...TSRA ARE LAGGING FARTHER AND FARTHER S WITHIN THE OVERALL SHRA AREA. HIGH RES MODEL GUIDANCE...PARTICULARLY THE HIGH RES RAPID REFRESH... HAS A DECENT HANDLE ON APPROACHING SHRA. UTILIZED RADAR TRENDS AND HIGH RES GUIDANCE TO SWING A PERIOD OF CATEGORICAL POPS ACROSS THE FCST AREA THIS MORNING. FORTUNATELY...PCPN AMOUNTS DON`T LOOK TO BE EXCESSIVE AS MAIN AREA OF TSRA WILL PASS BY TO THE S. STILL... EXPECT ROUGHLY 0.5 TO 0.75 INCHES WHICH WILL GIVE AREA RIVERS/STREAMS A BOOST IN FLOW. AS SUPPORTING SHORTWAVE MOVES NE OF THE AREA...MUCH OF THE AFTN MAY TURN DRY IN ITS WAKE. POPS WERE LOWERED INTO THE CHC/SCT CATEGORY...BUT BELIEVE MANY AREAS WILL PROBABLY SEE A GOOD PERIOD OF DRY WEATHER THIS AFTN. WITH PCPN AT A MINIMUM DURING THE AFTN...TEMPS WILL HAVE A CHANCE TO RESPOND...AT LEAST IN AREAS WHERE GENERAL EASTERLY FLOW IS NOT OFF THE GREAT LAKES. BUMPED TEMPS UP INTO THE UPPER 50S/LWR 60S ACROSS MUCH OF THE INTERIOR. HIGH RES RAPID REFRESH SHOWS TEMPS RISING TO AROUND 70F OVER THE INTERIOR W THIS AFTN...CERTAINLY POSSIBLE IF CLOUDS THIN OUT SUFFICIENTLY. AS SFC LOW PRES LIFTS FROM WRN WI ACROSS WRN LAKE SUPERIOR TONIGHT...WARM FRONT WILL ATTEMPT TO MOVE INTO UPPER MI. AT THIS POINT...IT APPEARS THE WARM FRONT MAY JUST SLIP INTO FAR SRN UPPER MI. ADDITIONAL SHRA/TSRA WILL LIKELY DEVELOP AS SFC LOW/WARM FRONT LIFT N...THOUGH PCPN COVERAGE PROBABLY WON`T BE AS WIDESPREAD AS WHAT WILL OCCUR THIS MORNING. WITH ELEVATED CAPE UP AROUND 1000J/KG AND DEEP LAYER SHEAR AROUND 30KT OR SO...STORMS WILL HAVE THE POTENTIAL TO BECOME ORGANIZED WITH ISOLD SVR POSSIBLE...MAINLY OVER FAR SCNTRL UPPER MI...CLOSER TO WARM FRONT. MAIN THREAT SHOULD BE HAIL...BUT WITH PRECIPITABLE WATER 200-250PCT OF NORMAL...HVY RAINFALL WILL BE A GOOD BET WITH ANY TSRA. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 504 AM EDT MON MAY 12 2014 DEEP TROUGH FOR MAY AND REALLY ANYTIME OF THE YEAR STRETCHES FROM CENTRAL CANADA TO THE SOUTHERN PLAINS ON TUESDAY. SFC LOW CURRENTLY OVER THE CENTRAL PLAINS SHOULD BE JUST NORTHWEST OF LK SUPERIOR DAYBREAK ON TUESDAY. OCCLUDED FRONT WILL BE SLICING ACROSS CWA THROUGH MID MORNING...EXITING EASTERN CWA BY EARLY AFTN. SHOULD BE AT LEAST SCT SHRA/TSRA EXPECTED ALONG AND AHEAD OF FRONT AS HIGHER 1000-850MB THETA-E POOLS ALONG THE BOUNDARY. SHARP DRYING ENDS ANY RAIN QUICKLY OVER WEST HALF IN THE MORNING...BUT MAY SEE ISOLD SHRA/TSRA OVER FAR SOUTHEAST CWA AS WEAK LOW-LEVEL CONVERGENCE LINGERS AND AS ANOTHER WEAKER SHORTWAVE/Q-VECTOR CONVERGENCE AT H85-H5 LIFTS OVER FAR EAST CWA. ANY STORMS AHAEAD OF FRONT IN THE MORNING SHOULD BE WEAK AS 1-6KM MUCAPE AND MLCAPE BOTH DIMINISH STEADILY COMPARED TO THE OVERNIGHT HOURS. TEMPS WILL RISE INTO THE 60S OVER THE CNTRL WHERE WEST WINDS DOWNSLOPE...IMT-ESC-MNM...BUT WILL STAY IN THE 50S OVER THE WESTERN/NORTHWEST CWA WITH GRADIENT WINDS OFF LK SUPERIOR. THOSE WINDS COULD BE QUITE GUSTY...ESPECIALLY OVER THE MORE EXPOSED KEWEENAW...WHERE NAM/GFS SOUNDINGS INDICATE MIXED LAYER BUILDING TO H85-H8 WITH WINDS OVER 35 KTS IN THE MIXED LAYER. QUIET WEATHER TUESDAY NIGHT AND WEDNESDAY AS DEEP SFC LOW SLOWLY LIFTS TO JAMES BAY/HUDSON BAY. GRADIENT WEST FLOW STAYS OVER UPR MICHIGAN...BUT WILL LIGHTEN ENOUGH ON WEDNESDAY TO RESULT IN LAKE BREEZES. SLIM CHANCE THAT RESULTING LOW-LEVEL CONVERGENCE ADDED TO WEAK H7-H5 FORCING FM SHORTWAVE DROPPING ACROSS ON PERIFERY OF DEEP TROUGH ALOFT COULD TRIGGER A FEW SHOWERS/SPRINKLES INTERIOR CENTRAL. DEEP MIXING TO H8 WILL LIMIT POTENTIAL THOUGH AS LOW-LEVEL RH VALUES DROP OFF BLO 40 PCT. MAX TEMPS SHOULD PUSH INTO THE 50S INLAND AND FALL BACK INTO THE 40S NEAR LK SUPERIOR ONCE LAKE BREEZE DEVELOPS. THE FORECAST FOR THURSDAY INTO FRIDAY REMAINS UNCERTAIN. AT THE LEAST...TEMPS WILL BE BLO NORMAL FOR MOST CWA...PERHAPS BY MORE THAN 10-15F OVER THE NORTHERN CWA. ECMWF STILL SUPPORTS POTENTIAL FOR ACCUMULATING SNOW...NOW MAINLY DELAYED UNTIL THURSDAY NIGHT THROUGH FRIDAY AND POSSIBLY INTO FRIDAY NIGHT. LATEST UKMET ALSO IN LINE WITH THE ECMWF IDEA. MEANWHILE...GFS AND GEM-NH STAY WITH PROGRESSIVE IDEA INDICATING STRONG SHORTWAVE ROUNDING BASE OF DEEP TROUGH STAYS SEPARATE ENOUGH FROM TROUGH FROM HUDSON BAY TO THE NORTHERN PLAINS TO LIMIT PHASING. IF GFS THEME IDEA IS RIGHT...WOULD SEE SETUP WITH MORE DIURNALLY DRIVEN MAINLY RAIN SHOWERS DUE TO INSTABILITY ALOFT BENEATH THE TROUGH AXIS. IF THE ECMWF AND UKMET ARE ON THE RIGHT TRACK...THEY INDICATE ENOUGH PHASING BTWN THE LARGE SCALE TROUGHS TO DRAG A SFC LOW PRESSURE SYSTEM NORTHWARD OVER THE CNTRL GREAT LAKES INTO TOWARD THE UPPER GREAT LAKES THURSDAY INTO FRIDAY. WITH THAT SCNEARIO...WIDESPREAD RAIN AND SNOW THURSDAY EVENING WOULD CHANGE TO SNOW THURSDAY NIGHT INTO MUCH OF FRIDAY AND NORTHERLY FLOW WOULD ONLY BOOST THE SNOW OVER HIGHER TERRAIN AREAS NEAR LK SUPERIOR. SNOW COULD BE PRETTY WIDESRPEAD AS PYTPE WITH H85 TEMPS DROPPING BLO -5C AND SINCE 1000-850MB THICKNESSES FALL BLO 1300M. PHASING SYSTEMS ARE ALWAYS TOUGH TO FORECAST. ADD TO THAT FACT THAT WE ARE PUSHING INTO MIDDLE OF MAY AND IT MAKES IT REALLY TOUGH TO SAY IF UKMET AND ECMWF SOLUTION WILL WORK OUT AS FORECAST. SINCE ECMWF ENSEMBLE MEAN WOULD ALSO SUPPORT SIMILAR IDEA AND SOME CANADIAN ENSEMBLES HAVE SHOWN THIS RECENTLY IT DOES SUGGEST THE IDEA AT LEAST HAS SOME MERIT COMPARED TO JUST ONE ROUGE OPERATIONAL MODEL RUN SHOWING A BIG STORM IN THE FAR REACHES OF THE EXTENDED. ONCE THE SYSTEM OR JUST THE OPEN TROUGH MOVES BY...WEEKEND LOOKS DRIER WITH GRADUAL WARMING TREND. DID NOT STRAY FROM CONSENSUS LOW CHANCE POPS FOR NEXT WEEKEND ATTM. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 128 AM EDT MON MAY 12 2014 LINGERING DRY AIR AT THE LOW LEVELS WITH PREVAILING VFR CONDITIONS ARE EXPECTED TIL LATE IN THE NIGHT. A NORTHWARD MOVING LOW AND A WARM FRONT WILL SPREAD SHRA INTO UPPER MI...MAINLY AFT 09Z ALTHOUGH THERE IS STILL SOME UNCERTAINTY IN HOW FAST PCPN WILL DEVELOP. KIWD HAS THE BEST CHC OF CONDITIONS FALLING TO MVFR OVERNIGHT WITH THE ONSET OF RAIN. EXPECT ALL SITES TO QUICKLY FALL TO IFR OR LIFR IN LOWERING STRATUS BY 12Z OR SHORTLY THEREAFTER WITH CONTINUED SHOWERS AND ADVECTION OF HIGHER DEWPOINTS INTO THE AREA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 504 AM EDT MON MAY 12 2014 EXPECT PERIOD OF STRONGER WINDS OVER LAKE SUPERIOR. APPROACHING LOW PRESSURE SYSTEM RESULTS IN NORTHEAST WINDS INCREASING TO GALES BY AFTN OVER WEST HALF OF LK SUPERIOR. WINDS TO 30 KTS OVER REST OF LK SUPERIOR. STRONG WINDS DIMINISH BRIEFLY LATER THIS EVENING AND OVERNIGHT TONIGHT AS THE LOW SLIDES ACROSS WESTERN LK SUPERIOR. ONCE THE LOW MOVES NORTH OF THE LAKE ON TUESDAY MORNING...STRONG WEST WINDS KICK UP. EXPECT THESE STRONG WESTERLIES...PROBABLY REACHING GALES ON TUESDAY OVER NCNTRL LK SUPERIOR...TO SLOWLY FADE BLO 25 KTS BY WEDNESDAY MORNING. WINDS REST OF THE WEEK WILL MAINLY BE BLO 20 KTS. HOWEVER...A LOW PRESSURE SYSTEM COULD IMPACT THE REGION LATE THIS WEEK WITH WINDS OVER 25 KTS THURSDAY INTO FRIDAY. UNCERTAINTY IS HIGH WITH THAT SYSTEM THOUGH...SO CURRENT FORECAST WILL ONLY CALL FOR NORTHWEST TO 20 KTS AT THIS TIME. && .HYDROLOGY... ISSUED AT 504 AM EDT MON MAY 12 2014 WIDESRPEAD MODERATE TO HEAVY RAIN WILL AFFECT ALL OF UPR MICHIGAN THROUGH EARLY THIS AFTN BEFORE DIMINISHING...THEN THERE MAY BE ANOTHER PERIOD OF MODERATE RAINFALL TONIGHT. RAINFALL AMOUNTS MAY EXCEED ONE INCH TODAY OVER PORTIONS OF WESTERN UPR MICHIGAN. RAIN CHANCES DIMINISH FROM WEST TO EAST ON TUESDAY AS A FRONTAL BOUNDARY EXITS THE REGION. RAINFALL WILL ONLY ADD TO THE ONGOING SNOWMELT AND ALREADY HIGH FLOWS ON AREA RIVERS AND STREAMS. THE PRIMARY CHANGE TO ONGOING HEADLINES WAS LAST EVENING...WHEN BASED ON EXPECTED RAINFALL...WHICH LOOKS LIKE IT IS WORKING OUT...ADVISORIES WERE UPGRADED TO WARNINGS FOR THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. THE WARNING FOR THE STURGEON RIVER NEAR CHASSELL AND THE ADVISORY FOR THE STURGEON RIVER NEAR ALSTON CONTINUE...AS DOES THE ADVISORY FOR THE MICHIGAMME RIVER DOWNSTREAM OF WAY DAM...TO THE EAST OF CRYSTAL FALLS IN IRON COUNTY. GIVEN THE RAINFALL THAT WILL AFFECT THE AREA THE NEXT 24-36 HOURS...RIVER LEVELS WILL KEEP RISING AND ADJUSTMENTS WILL LIKELY BE NEEDED BASED ON LATEST TRENDS. ALL THIS WATER DUE TO THE SNOWMELT AND THE RAINFALL WILL TAKE A WHILE TO WORK THROUGH THE RIVERS...SO IT IS QUITE LIKELY THAT HIGHER RIVER FLOWS AND THE ASSOCIATED ADVISORIES AND WARNINGS ON AREA RIVERS WILL CONTINUE THROUGH LATE THIS WEEK...IF NOT INTO NEXT WEEKEND. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING FROM 10 AM THIS MORNING TO 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...JLB MARINE...JLA HYDROLOGY...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 AM EDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 347 PM EDT SUN MAY 11 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE ENERGY ROUNDING BASE OF AMPLIFIED TROF OVER THE FOUR CORNERS REGION OF THE SW CONUS. MODELS SHOW THIS STRONG SHORTWAVE BEGINNING TO EJECT NE FROM WRN/CENTRAL PLAINS TONIGHT AS ITS ASSOC SFC LOW LIFTS NE THROUGH THE PLAINS. INCREASING MOISTURE AND ISENTROPIC ASCENT AHEAD OF THIS LOW PRES SYSTEM SHOULD SIGNAL THE BEGINNING OF A FAIRLY WET PERIOD FOR THE CWA STARTING LATE TONIGHT AND CONTINUING INTO EARLY TUESDAY. TONIGHT...AS THE STRONGER SHORTWAVE BEGINS TO EJECT OUT OF THE DEEPENING UPPER TROF THE SFC LOW PRES WILL IN TURN LIFT NE THRU THE PLAINS. THE EVENING SHOULD REMAIN DRY...AND PERHAPS CONTINUE INTO THE OVERNIGHT OVER THE NE HALF OF THE FCST AREA CLOSER TO DRY LOW-LEVEL NE TRAJECTORIES OUT OF SFC HIGH PRES IN ONTARIO. MOST OF THE MODELS SHOW INCREASING 850-700 MB MOISTURE TRANSPORT AND ADVECTION INTO THE AREA FM THE SOUTH BTWN 06-12Z ALONG WITH INCREASING 300-305K WAA/ISENTROPIC ASCENT AHEAD OF THE APPROACHING LOW PRES SYSTEM. MODELS ALSO INDICATE A SUBTLE SHORTWAVE WILL LIFT NE INTO THE UPPER MISSISSIPPI VALLEY LATE TONIGHT THAT WILL FURTHER AID THE DEVELOPMENT/SPREAD OF SHRA NE INTO UPPER MI DURING THE OVERNIGHT. NOT MUCH INSTABILITY IS NOTED PER 0-3KM MUCAPE OFF THE NAM/GFS. WITH A COUPLE HUNDRED J/KG AND SHOWALTER INDEX FALLING JUST BLO 0C OVER THE FAR SCNTRL LATE TONIGHT IN MOST MODEL GUIDANCE...WILL CONTINUE THE MENTION OF THUNDER IN THAT AREA LATE TONIGHT. MONDAY...WITH H85 WARM FRONT IN THE VICINITY...MODELS SHOW CONTINUED MOISTURE TRANSPORT/ADVECTION AT H85-H7 ACROSS THE FRONTAL BOUNDARY AS PWATS OVER OUR AREA RISE TO AROUND 1.5 INCHES OR WELL OVER 200 PCT OF NORMAL. SHORTWAVE/PV ANAMOLY EMERGING NORTHEAST OUT OF THE WESTERN CONUS TROUGH WILL SPREAD AREA OF H85-H5 Q-VECTOR CONVERGENCE INTO THE UPPER GREAT LAKES BY MONDAY AFTERNOON. DESPITE THESE FAVORABLE FACTORS FOR SHOWERS...MODELS STILL DIFFER SOMEWHAT ON PLACEMENT OF MAXIMUM MOISTURE ADVECTION...WITH THE GFS AND NAM INDICATING BEST MOISTURE ADVECTION WEST AND THE REG GEM TO THE EAST. HOWEVER CORFIDI VECTORS...BOTH FORWARD AND BACKWARD PROPAGATING...ARE GENERALLY ORIENTED FROM WEST TO EAST ACROSS THE FCST AREA WHICH WOULD ARGUE SHOWERS MAKING IT INTO THE WRN FCST AREA SHOULD ADVECT INTO THE ERN COUNTIES AS WELL. GOING FCST LIKELY POPS STILL SEEM REASONABLE CONSIDERING THE H85 FRONT IS IN THE VICINTY. WILL CONTINUE IDEA OF LIKELY POPS WEST IN THE MORNING SPREADING EAST INTO THE AFTERNOON HRS. ALSO WILL CONTINUE TO KEEP MENTION OF TSRA MAINLY OVER SOUTH HALF INTO THE WESTERN CWA ALONG NORTHERN GRADIENT OF ELEVATED INSTABILITY WITH SEVERAL HUNDRED J/KG OF ELEVATED CAPE AND NEG SHOWALTER INDICES. BIGGEST THREAT WITH ANY TSRA WILL BE HEAVY RAIN GIVEN HIGH PWATS ACROSS AREA. ANY HEAVY RAIN OVER THE WRN COUNTIES WILL CONTINUE TO ADD MORE RUNOFF TO RIVERS ALREADY RUNNING NEAR BANKFULL...ESPECIALLY THE STURGEON...TRAP ROCK AND MICHIGAMME RIVERS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 504 AM EDT MON MAY 12 2014 DEEP TROUGH FOR MAY AND REALLY ANYTIME OF THE YEAR STRETCHES FROM CENTRAL CANADA TO THE SOUTHERN PLAINS ON TUESDAY. SFC LOW CURRENTLY OVER THE CENTRAL PLAINS SHOULD BE JUST NORTHWEST OF LK SUPERIOR DAYBREAK ON TUESDAY. OCCLUDED FRONT WILL BE SLICING ACROSS CWA THROUGH MID MORNING...EXITING EASTERN CWA BY EARLY AFTN. SHOULD BE AT LEAST SCT SHRA/TSRA EXPECTED ALONG AND AHEAD OF FRONT AS HIGHER 1000-850MB THETA-E POOLS ALONG THE BOUNDARY. SHARP DRYING ENDS ANY RAIN QUICKLY OVER WEST HALF IN THE MORNING...BUT MAY SEE ISOLD SHRA/TSRA OVER FAR SOUTHEAST CWA AS WEAK LOW-LEVEL CONVERGENCE LINGERS AND AS ANOTHER WEAKER SHORTWAVE/Q-VECTOR CONVERGENCE AT H85-H5 LIFTS OVER FAR EAST CWA. ANY STORMS AHAEAD OF FRONT IN THE MORNING SHOULD BE WEAK AS 1-6KM MUCAPE AND MLCAPE BOTH DIMINISH STEADILY COMPARED TO THE OVERNIGHT HOURS. TEMPS WILL RISE INTO THE 60S OVER THE CNTRL WHERE WEST WINDS DOWNSLOPE...IMT-ESC-MNM...BUT WILL STAY IN THE 50S OVER THE WESTERN/NORTHWEST CWA WITH GRADIENT WINDS OFF LK SUPERIOR. THOSE WINDS COULD BE QUITE GUSTY...ESPECIALLY OVER THE MORE EXPOSED KEWEENAW...WHERE NAM/GFS SOUNDINGS INDICATE MIXED LAYER BUILDING TO H85-H8 WITH WINDS OVER 35 KTS IN THE MIXED LAYER. QUIET WEATHER TUESDAY NIGHT AND WEDNESDAY AS DEEP SFC LOW SLOWLY LIFTS TO JAMES BAY/HUDSON BAY. GRADIENT WEST FLOW STAYS OVER UPR MICHIGAN...BUT WILL LIGHTEN ENOUGH ON WEDNESDAY TO RESULT IN LAKE BREEZES. SLIM CHANCE THAT RESULTING LOW-LEVEL CONVERGENCE ADDED TO WEAK H7-H5 FORCING FM SHORTWAVE DROPPING ACROSS ON PERIFERY OF DEEP TROUGH ALOFT COULD TRIGGER A FEW SHOWERS/SPRINKLES INTERIOR CENTRAL. DEEP MIXING TO H8 WILL LIMIT POTENTIAL THOUGH AS LOW-LEVEL RH VALUES DROP OFF BLO 40 PCT. MAX TEMPS SHOULD PUSH INTO THE 50S INLAND AND FALL BACK INTO THE 40S NEAR LK SUPERIOR ONCE LAKE BREEZE DEVELOPS. THE FORECAST FOR THURSDAY INTO FRIDAY REMAINS UNCERTAIN. AT THE LEAST...TEMPS WILL BE BLO NORMAL FOR MOST CWA...PERHAPS BY MORE THAN 10-15F OVER THE NORTHERN CWA. ECMWF STILL SUPPORTS POTENTIAL FOR ACCUMULATING SNOW...NOW MAINLY DELAYED UNTIL THURSDAY NIGHT THROUGH FRIDAY AND POSSIBLY INTO FRIDAY NIGHT. LATEST UKMET ALSO IN LINE WITH THE ECMWF IDEA. MEANWHILE...GFS AND GEM-NH STAY WITH PROGRESSIVE IDEA INDICATING STRONG SHORTWAVE ROUNDING BASE OF DEEP TROUGH STAYS SEPARATE ENOUGH FROM TROUGH FROM HUDSON BAY TO THE NORTHERN PLAINS TO LIMIT PHASING. IF GFS THEME IDEA IS RIGHT...WOULD SEE SETUP WITH MORE DIURNALLY DRIVEN MAINLY RAIN SHOWERS DUE TO INSTABILITY ALOFT BENEATH THE TROUGH AXIS. IF THE ECMWF AND UKMET ARE ON THE RIGHT TRACK...THEY INDICATE ENOUGH PHASING BTWN THE LARGE SCALE TROUGHS TO DRAG A SFC LOW PRESSURE SYSTEM NORTHWARD OVER THE CNTRL GREAT LAKES INTO TOWARD THE UPPER GREAT LAKES THURSDAY INTO FRIDAY. WITH THAT SCNEARIO...WIDESPREAD RAIN AND SNOW THURSDAY EVENING WOULD CHANGE TO SNOW THURSDAY NIGHT INTO MUCH OF FRIDAY AND NORTHERLY FLOW WOULD ONLY BOOST THE SNOW OVER HIGHER TERRAIN AREAS NEAR LK SUPERIOR. SNOW COULD BE PRETTY WIDESRPEAD AS PYTPE WITH H85 TEMPS DROPPING BLO -5C AND SINCE 1000-850MB THICKNESSES FALL BLO 1300M. PHASING SYSTEMS ARE ALWAYS TOUGH TO FORECAST. ADD TO THAT FACT THAT WE ARE PUSHING INTO MIDDLE OF MAY AND IT MAKES IT REALLY TOUGH TO SAY IF UKMET AND ECMWF SOLUTION WILL WORK OUT AS FORECAST. SINCE ECMWF ENSEMBLE MEAN WOULD ALSO SUPPORT SIMILAR IDEA AND SOME CANADIAN ENSEMBLES HAVE SHOWN THIS RECENTLY IT DOES SUGGEST THE IDEA AT LEAST HAS SOME MERIT COMPARED TO JUST ONE ROUGE OPERATIONAL MODEL RUN SHOWING A BIG STORM IN THE FAR REACHES OF THE EXTENDED. ONCE THE SYSTEM OR JUST THE OPEN TROUGH MOVES BY...WEEKEND LOOKS DRIER WITH GRADUAL WARMING TREND. DID NOT STRAY FROM CONSENSUS LOW CHANCE POPS FOR NEXT WEEKEND ATTM. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 128 AM EDT MON MAY 12 2014 LINGERING DRY AIR AT THE LOW LEVELS WITH PREVAILING VFR CONDITIONS ARE EXPECTED TIL LATE IN THE NIGHT. A NORTHWARD MOVING LOW AND A WARM FRONT WILL SPREAD SHRA INTO UPPER MI...MAINLY AFT 09Z ALTHOUGH THERE IS STILL SOME UNCERTAINTY IN HOW FAST PCPN WILL DEVELOP. KIWD HAS THE BEST CHC OF CONDITIONS FALLING TO MVFR OVERNIGHT WITH THE ONSET OF RAIN. EXPECT ALL SITES TO QUICKLY FALL TO IFR OR LIFR IN LOWERING STRATUS BY 12Z OR SHORTLY THEREAFTER WITH CONTINUED SHOWERS AND ADVECTION OF HIGHER DEWPOINTS INTO THE AREA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 504 AM EDT MON MAY 12 2014 EXPECT PERIOD OF STRONGER WINDS OVER LAKE SUPERIOR. APPROACHING LOW PRESSURE SYSTEM RESULTS IN NORTHEAST WINDS INCREASING TO GALES BY AFTN OVER WEST HALF OF LK SUPERIOR. WINDS TO 30 KTS OVER REST OF LK SUPERIOR. STRONG WINDS DIMINISH BRIEFLY LATER THIS EVENING AND OVERNIGHT TONIGHT AS THE LOW SLIDES ACROSS WESTERN LK SUPERIOR. ONCE THE LOW MOVES NORTH OF THE LAKE ON TUESDAY MORNING...STRONG WEST WINDS KICK UP. EXPECT THESE STRONG WESTERLIES...PROBABLY REACHING GALES ON TUESDAY OVER NCNTRL LK SUPERIOR...TO SLOWLY FADE BLO 25 KTS BY WEDNESDAY MORNING. WINDS REST OF THE WEEK WILL MAINLY BE BLO 20 KTS. HOWEVER...A LOW PRESSURE SYSTEM COULD IMPACT THE REGION LATE THIS WEEK WITH WINDS OVER 25 KTS THURSDAY INTO FRIDAY. UNCERTAINTY IS HIGH WITH THAT SYSTEM THOUGH...SO CURRENT FORECAST WILL ONLY CALL FOR NORTHWEST TO 20 KTS AT THIS TIME. && .HYDROLOGY... ISSUED AT 504 AM EDT MON MAY 12 2014 WIDESRPEAD MODERATE TO HEAVY RAIN WILL AFFECT ALL OF UPR MICHIGAN THROUGH EARLY THIS AFTN BEFORE DIMINISHING...THEN THERE MAY BE ANOTHER PERIOD OF MODERATE RAINFALL TONIGHT. RAINFALL AMOUNTS MAY EXCEED ONE INCH TODAY OVER PORTIONS OF WESTERN UPR MICHIGAN. RAIN CHANCES DIMINISH FROM WEST TO EAST ON TUESDAY AS A FRONTAL BOUNDARY EXITS THE REGION. RAINFALL WILL ONLY ADD TO THE ONGOING SNOWMELT AND ALREADY HIGH FLOWS ON AREA RIVERS AND STREAMS. THE PRIMARY CHANGE TO ONGOING HEADLINES WAS LAST EVENING...WHEN BASED ON EXPECTED RAINFALL...WHICH LOOKS LIKE IT IS WORKING OUT...ADVISORIES WERE UPGRADED TO WARNINGS FOR THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. THE WARNING FOR THE STURGEON RIVER NEAR CHASSELL AND THE ADVISORY FOR THE STURGEON RIVER NEAR ALSTON CONTINUE...AS DOES THE ADVISORY FOR THE MICHIGAMME RIVER DOWNSTREAM OF WAY DAM...TO THE EAST OF CRYSTAL FALLS IN IRON COUNTY. GIVEN THE RAINFALL THAT WILL AFFECT THE AREA THE NEXT 24-36 HOURS...RIVER LEVELS WILL KEEP RISING AND ADJUSTMENTS WILL LIKELY BE NEEDED BASED ON LATEST TRENDS. ALL THIS WATER DUE TO THE SNOWMELT AND THE RAINFALL WILL TAKE A WHILE TO WORK THROUGH THE RIVERS...SO IT IS QUITE LIKELY THAT HIGHER RIVER FLOWS AND THE ASSOCIATED ADVISORIES AND WARNINGS ON AREA RIVERS WILL CONTINUE THROUGH LATE THIS WEEK...IF NOT INTO NEXT WEEKEND. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING FROM 10 AM THIS MORNING TO 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...JLB MARINE...JLA HYDROLOGY...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 AM EDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 347 PM EDT SUN MAY 11 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE ENERGY ROUNDING BASE OF AMPLIFIED TROF OVER THE FOUR CORNERS REGION OF THE SW CONUS. MODELS SHOW THIS STRONG SHORTWAVE BEGINNING TO EJECT NE FROM WRN/CENTRAL PLAINS TONIGHT AS ITS ASSOC SFC LOW LIFTS NE THROUGH THE PLAINS. INCREASING MOISTURE AND ISENTROPIC ASCENT AHEAD OF THIS LOW PRES SYSTEM SHOULD SIGNAL THE BEGINNING OF A FAIRLY WET PERIOD FOR THE CWA STARTING LATE TONIGHT AND CONTINUING INTO EARLY TUESDAY. TONIGHT...AS THE STRONGER SHORTWAVE BEGINS TO EJECT OUT OF THE DEEPENING UPPER TROF THE SFC LOW PRES WILL IN TURN LIFT NE THRU THE PLAINS. THE EVENING SHOULD REMAIN DRY...AND PERHAPS CONTINUE INTO THE OVERNIGHT OVER THE NE HALF OF THE FCST AREA CLOSER TO DRY LOW-LEVEL NE TRAJECTORIES OUT OF SFC HIGH PRES IN ONTARIO. MOST OF THE MODELS SHOW INCREASING 850-700 MB MOISTURE TRANSPORT AND ADVECTION INTO THE AREA FM THE SOUTH BTWN 06-12Z ALONG WITH INCREASING 300-305K WAA/ISENTROPIC ASCENT AHEAD OF THE APPROACHING LOW PRES SYSTEM. MODELS ALSO INDICATE A SUBTLE SHORTWAVE WILL LIFT NE INTO THE UPPER MISSISSIPPI VALLEY LATE TONIGHT THAT WILL FURTHER AID THE DEVELOPMENT/SPREAD OF SHRA NE INTO UPPER MI DURING THE OVERNIGHT. NOT MUCH INSTABILITY IS NOTED PER 0-3KM MUCAPE OFF THE NAM/GFS. WITH A COUPLE HUNDRED J/KG AND SHOWALTER INDEX FALLING JUST BLO 0C OVER THE FAR SCNTRL LATE TONIGHT IN MOST MODEL GUIDANCE...WILL CONTINUE THE MENTION OF THUNDER IN THAT AREA LATE TONIGHT. MONDAY...WITH H85 WARM FRONT IN THE VICINITY...MODELS SHOW CONTINUED MOISTURE TRANSPORT/ADVECTION AT H85-H7 ACROSS THE FRONTAL BOUNDARY AS PWATS OVER OUR AREA RISE TO AROUND 1.5 INCHES OR WELL OVER 200 PCT OF NORMAL. SHORTWAVE/PV ANAMOLY EMERGING NORTHEAST OUT OF THE WESTERN CONUS TROUGH WILL SPREAD AREA OF H85-H5 Q-VECTOR CONVERGENCE INTO THE UPPER GREAT LAKES BY MONDAY AFTERNOON. DESPITE THESE FAVORABLE FACTORS FOR SHOWERS...MODELS STILL DIFFER SOMEWHAT ON PLACEMENT OF MAXIMUM MOISTURE ADVECTION...WITH THE GFS AND NAM INDICATING BEST MOISTURE ADVECTION WEST AND THE REG GEM TO THE EAST. HOWEVER CORFIDI VECTORS...BOTH FORWARD AND BACKWARD PROPAGATING...ARE GENERALLY ORIENTED FROM WEST TO EAST ACROSS THE FCST AREA WHICH WOULD ARGUE SHOWERS MAKING IT INTO THE WRN FCST AREA SHOULD ADVECT INTO THE ERN COUNTIES AS WELL. GOING FCST LIKELY POPS STILL SEEM REASONABLE CONSIDERING THE H85 FRONT IS IN THE VICINTY. WILL CONTINUE IDEA OF LIKELY POPS WEST IN THE MORNING SPREADING EAST INTO THE AFTERNOON HRS. ALSO WILL CONTINUE TO KEEP MENTION OF TSRA MAINLY OVER SOUTH HALF INTO THE WESTERN CWA ALONG NORTHERN GRADIENT OF ELEVATED INSTABILITY WITH SEVERAL HUNDRED J/KG OF ELEVATED CAPE AND NEG SHOWALTER INDICES. BIGGEST THREAT WITH ANY TSRA WILL BE HEAVY RAIN GIVEN HIGH PWATS ACROSS AREA. ANY HEAVY RAIN OVER THE WRN COUNTIES WILL CONTINUE TO ADD MORE RUNOFF TO RIVERS ALREADY RUNNING NEAR BANKFULL...ESPECIALLY THE STURGEON...TRAP ROCK AND MICHIGAMME RIVERS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 329 PM EDT SUN MAY 11 2014 AT THE START OF THE PERIOD /00Z TUE/ MODELS ARE IN DECENT LARGE SCALE AGREEMENT IN SHOWING A SHARP AND DEEP 500MB TROUGH FROM THE SASK/MANITOBA BORDER S ACROSS THE DAKOTAS THEN TO THE FOUR CORNERS REGION. A 1004MB SFC LOW WILL BE SOMEWHERE IN THE SERN MN TO NWRN WI. MODELS HAVE BEEN TRENDING TOWARD THE CURRENT SOLUTION THAT TAKES THE SFC LOW W OF THE CWA TO JUST N OF THE MN ARROWHEAD BY 12Z TUE. WITH THE MORE NLY TRACK...MODELS ARE NOW SHOWING THE SFC WARM FRONT MOVING INTO THE FAR SRN CWA MON NIGHT...BUT WITH COLD LAKE TEMPS AND CONVECTION EXPECTED ALONG THE FRONT...CONFIDENCE IN THE FRONT MOVING THAT FAR N IS LOW. FORCING FROM UPPER LEVEL HEIGHT FALLS FROM THE DEEPENING TROUGH...GOOD MOISTURE TRANSPORT AND ISENTROPIC ASCENT WILL FAVOR PERIODS OF MODERATE RAIN SHOWERS MON NIGHT INTO EARLY TUE. THE OCCLUDED/COLD FRONT WILL MOVE THROUGH FROM LATE MON NIGHT INTO TUE...BRINGING AN END TO THE BULK OF THE PRECIP. SOME SHOWERS COULD REDEVELOP BEHIND THE FRONT AS CLEARING OVER THE WRN U.P. MAY ALLOW FOR ENOUGH INSTABILITY. MODELS GENERALLY SHOW ADDITIONAL QPF AMOUNTS OF AN INCH...BUT THAT WILL BE HIGHLY DEPENDENT ON EXACT DETAILS OF CONVECTION...MAKING EXACT PRECIP AMOUNTS HIGHLY UNCERTAIN. INSTABILITY FOR CONVECTION WILL ALSO BE HIGHLY UNCERTAIN DUE TO DEPENDENCY ON WARM FRONTAL LOCATION AND OTHER CONVECTION. IF THE FRONT CAN MAKE IT FARTHER N...THE WARM NOSE AT 900MB MAY BE STRONG ENOUGH TO LEAD TO GREATER ELEVATED CONVECTION. GFS AND NAM ARE SHOWING UP TO AROUND 1000 J/KG OF ELEVATED CAPE OVER THE SCENTRAL CWA...BUT STILL THINK THAT IS NOT AS LIKELY AS THE FRONT WILL PROBABLY STAY FARTHER S. IF THE WORST CASE SCENARIO OF THE FARTHER N FRONTAL POSITION DOES OCCUR...SOME HAIL WOULD BE POSSIBLE SCENTRAL. THE ADDITIONAL QPF AMOUNTS /COMBINED WITH PRECIP ON MON/ WOULD LIKELY LEAD TO ADDITIONAL FLOODING CONCERNS ON AREA RIVERS THAT ALREADY HAVE ELEVATED LEVELS. THE UPPER TROUGH MOVES OVERHEAD THROUGH MUCH OF THE REST OF THE WORK WEEK...ALTHOUGH THE ECMWF CLOSES IT OFF INTO A LOW THU INTO FRI. THE ECMWF SOLUTION WOULD RESULT IN MORE WIDESPREAD PRECIP THU INTO FRI...BUT THE GFS AND GEM SOLUTIONS WITH THE OPEN TROUGH WOULD LEAD TO SCATTERED SHOWER ACTIVITY MAINLY DURING PEAK HEATING WED THROUGH FRI. THIS DUE TO 850MB TEMPS OF -2C TO -4C WED THROUGH FRI NIGHT /AND AS COLD AS -7C IF THE ECMWF SOLUTION PANS OUT/. OF COURSE...THIS WILL LEAD TO A RETURN OF SIGNIFICANTLY BELOW NORMAL TEMPS /10-15 DEGREES BELOW NORMAL/. NEXT WEEKEND LOOKS DRIER AND WARMER AS RIDGING MOVES OVERHEAD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 128 AM EDT MON MAY 12 2014 LINGERING DRY AIR AT THE LOW LEVELS WITH PREVAILING VFR CONDITIONS ARE EXPECTED TIL LATE IN THE NIGHT. A NORTHWARD MOVING LOW AND A WARM FRONT WILL SPREAD SHRA INTO UPPER MI...MAINLY AFT 09Z ALTHOUGH THERE IS STILL SOME UNCERTAINTY IN HOW FAST PCPN WILL DEVELOP. KIWD HAS THE BEST CHC OF CONDITIONS FALLING TO MVFR OVERNIGHT WITH THE ONSET OF RAIN. EXPECT ALL SITES TO QUICKLY FALL TO IFR OR LIFR IN LOWERING STRATUS BY 12Z OR SHORTLY THEREAFTER WITH CONTINUED SHOWERS AND ADVECTION OF HIGHER DEWPOINTS INTO THE AREA. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 347 PM EDT SUN MAY 11 2014 NE WINDS 15-25 KTS THIS EVENING WILL BEGIN TO INCREASE OVER WESTERN PORTIONS OF LK SUPERIOR LATE TONIGHT AND MORE SO ON MONDAY AS LOW PRESSURE APPROACHES FROM THE SOUTHWEST. DECIDED TO REPLACE GALE WATCH WITH GALE WARNING OVER WESTERN TWO ZONES LATE TONIGHT THROUGH TUE EVENING. WINDS OVER THE REST OF THE LAKE WILL STAY AT OR BLO 30 KTS. WINDS DIMINISH LATER MONDAY NIGHT AND THEN SWITCH TO THE WEST TO 20-25 KTS ON TUESDAY. LOW SLOWLY SLIDES TO THE NORTHEAST OF LK SUPERIOR REST OF THE WEEK...RESULTING IN NORTHWEST WINDS MAINLY STAYING BLO 20 KTS. && .HYDROLOGY... ISSUED AT 329 PM EDT SUN MAY 11 2014 HIGHS MOSTLY IN THE 60S TODAY WILL RESULT IN ADDITIONAL SNOWMELT OVER HIGHER TERRAIN OF NORTHERN UPR MICHIGAN. MINIMAL RAIN AMOUNTS ARE EXPECTED THROUGH AT LEAST EARLY TONIGHT...BUT RAIN CHANCES INCREASE LATE TONIGHT INTO TUESDAY MORNING. THERE IS A POTENTIAL FOR MODERATE TO HEAVY RAIN OVER THE AREAS THAT ARE STILL MELTING SNOW...SO THE RECENT HIGHER RIVER LEVELS WILL CONTINUE THROUGH MUCH OF THE UPCOMING WEEK. THE FLOOD WARNING CONTINUES FOR THE STURGEON RIVER NEAR CHASSELL...WHILE ADVISORIES ARE IN PLACE FOR OTHER PORTIONS OF THE STURGEON RIVER IN HOUGHTON AND BARAGA COUNTIES AS WELL AS PORTIONS OF THE MICHIGAMME RIVER. IF HEAVIER RAINS MATERIALIZE EARLY THIS WEEK... ADDITIONAL ADVISORIES AND WARNINGS MAY BE NEEDED. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 6 AM EDT /5 AM CDT/ THIS MORNING TO MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING FROM 10 AM THIS MORNING TO 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...TITUS AVIATION...JLB MARINE...VOSS HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
421 AM CDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 334 AM CDT MON MAY 12 2014 SHOWERS ARE PUSHING EAST OF OUR WEST CENTRAL WI COUNTIES EARLY THIS MORNING WITH JUST A FEW SCATTERED SHOWERS ACROSS THE MN COUNTIES. RAINFALL AMOUNTS OVERNIGHT FROM 1 TO 1.50 INCHES HAVE BEEN COMMON ACROSS SOUTHERN MN AND ADJOINING AREAS OF WEST CENTRAL WI. RAINFALL AMOUNTS DROP OFF TO AROUND A HALF INCH FROM WEST CENTRAL MN TO NW WI. THE DAY AHEAD WILL FEATURE A LOW PRESSURE SYSTEM MOVING SLOWLY NORTHEAST FROM IA TO THE SOUTHERN TWIN CITIES METRO BY EARLY THIS AFTERNOON. THE LOW SHOULD REACH FAR NORTHERN WI BY LATE THIS EVENING. THERE IS PLENTY OF POTENTIAL FOR SEVERE STORMS TO DEVELOP THIS AFTERNOON/EVENING IN THE VICINITY OF THE SURFACE LOW AND WARM FRONT EXTENDING TO THE EAST. LIMITING FACTORS WILL BE THE EXTENSIVE CLOUDINESS THAT WILL HOLD DOWN ON THE DESTABILIZATION. RAP DATA SHOWS A WARM POCKET MOVING NORTHEAST FROM IA THIS MORNING BETWEEN 650-700MB. THIS IS SQUARELY OVER WEST CENTRAL WI EARLY THIS AFTERNOON. LOW LEVEL LAPSE RATES SUFFER AS WELL AS SURFACE BASED CAPE. HOWEVER...BY LATE IN THE AFTERNOON...SOUNDING DATA FOR KEAU SHOWS THE POTENTIAL TO WARM ENOUGH TO GET PAST THE MID LEVEL WARM POCKET. SURFACE BASED CAPE REACHES A LITTLE MORE THAN 2000 J/KG. SHEAR IS ADEQUATE WITH 0-1KM REACHING 25 KNOTS WITH 0-6KM BETTER THAN 45 KNOTS. 500MB WINDS ARE VERY IMPRESSIVE WITH A CORE OF 60-70 KNOT WINDS PROGGED ACROSS THE TWIN CITIES AND WEST CENTRAL WI THIS AFTERNOON. OUR MPXWRF...THE HOPWRF AND THE SPCWRF START BREWING TROUBLE ALONG OUR MN/WI BORDER AREA BY 21Z WITH THE HINT OF A FEW SUPERCELLS ACROSS WEST CENTRAL WI INTO THE EARLY EVENING. GIVEN THE LOW LCLS...SHEAR AND WARM FRONT...A TORNADO OR TWO CAN NOT BE RULED OUT. IN FACT...THERE HAVE BEEN TORNADOES THE PAST TWO DAYS NEAR THE SURFACE LOW AND WARM FRONT. NORTHWEST WINDS WILL STRENGTHEN ACROSS THE FA TONIGHT IN THE WAKE OF THE LOW PRESSURE SYSTEM. THIS WILL USHER IN MUCH COOLER AIR THAT WILL BE WITH US FOR THE BALANCE OF THE WEEK AS A LARGE TROUGH ALOFT DOMINATES ACROSS THE MISSISSIPPI VALLEY REGION. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 334 AM CDT MON MAY 12 2014 THE THEME FOR THE LONG TERM PERIOD IS DRY WEATHER FOR THE UPPER MIDWEST. ALTHOUGH...IT WILL ALSO BE A COOL PERIOD MAINLY TUESDAY THROUGH FRIDAY AS TEMPERATURES WILL RUN 10 TO 15 DEGREES BELOW NORMAL. PICKING UP TUESDAY MORNING...THE UPPER LEVEL TROUGH AXIS WILL BE IN THE VICINITY OF THE WESTERN MN/EASTERN DAKOTAS BORDER. THE SURFACE LOW WILL HAVE LIFTED UP INTO ONTARIO NORTH OF LAKE SUPERIOR. THE NAM REMAINS STUBBORN IN HAVING THE MOVEMENT OF THE LOW A TAD SLOWER/GIVEN ITS DEEPER SOLUTION WITH THE TROUGH MONDAY NIGHT/...BUT IT HAS STARTED TO MOVE TOWARD THE GFS/EC SOLUTIONS. PREFERRED A EC/GFS BLEND THAT HAS THE LOW QUICKLY MOVING NORTH. THE UPPER TROUGH AND MOISTURE ON THE BACK SIDE OF THE LOW WARRANTED THE MENTION OF POPS ACROSS THE NORTHERN PART OF THE FA...BUT ANY PRECIPITATION WILL BE VERY LIGHT. WITH THE UPPER TROUGH OVERHEAD...TEMPERATURES WILL BE HELD IN THE 50S DURING THE DAY...AND WITH THE DEPARTING LOW NORTHWEST WINDS WILL BE BLUSTERY AND MAKE FOR A COOL DAY. WINDS SHOULD SLACKEN AND SKY COVER BEGIN TO BREAK UP TUESDAY EVENING. 850H TEMPS WILL FALL BELOW ZERO OVERNIGHT AND GIVEN WEAKENING WINDS AND AND DIMINISHING SKY COVER OVERNIGHT...TEMPERATURES BY EARLY WEDNESDAY MORNING WILL BE IN THE 30S ACROSS THE FA. LITTLE CHANGE IS EXPECTED WEDNESDAY AS THE AMPLIFIED UPPER TROUGH AND CORE OF THE COOL AIR REMAINS OVERHEAD. MEANWHILE...BOTH THE EAST COAST AND WEST COAST WILL HAVE HIGHLY AMPLIFIED RIDGING AND WARM TEMPERATURES. SLIGHT CHANCE POPS DO SHOW UP AGAIN WEDNESDAY AFTERNOON ACROSS THE WEST AS ADDITIONAL MOISTURE ALOFT ROTATES SOUTH ON THE BACK SIDE OF THE UPPER TROUGH. WOULD NOT BE SURPRISED IF LOW LEVEL DRY AIR PREVENTS ANYTHING FROM REACHING THE GROUND. WEDNESDAY NIGHT WILL BE COLDER AS 850H TEMPS DROP TO -2C TO -6C GENERALLY ACROSS THE FA. WIDESPREAD 30S ARE EXPECTED WITH SOME SPOTS HITTING THE FREEZING MARK. THE AMPLIFIED TROUGH WILL PUSH SLIGHTLY EAST AND BECOME A CLOSED UPPER LOW OVER WISCONSIN THURSDAY NIGHT INTO FRIDAY SO CYCLONICALLY CURVED FLOW MAY AGAIN PRODUCE VERY LIGHT PRECIP THURSDAY AFTERNOON. THE POPS ASSOCIATED WITH THIS TROUGH DURING THE MIDWEEK MAY BE OVERDONE BY THE LARGE SCALE SYNOPTIC MODELS...HOWEVER...SO WHILE THERE ARE SOME POPS IN THE FORECAST FOR THE MIDWEEK TIME FRAME...TOTAL AMOUNTS WILL BE UNDER A TENTH OF AN INCH...AND WILL LIKELY BE ZERO FOR PARTS OF THE AREA. WE`LL SEE THE CORE OF THE COOL AIR ALOFT PUSH EAST AT THE START OF THE WEEKEND AS THE WESTERN CONUS RIDGE STARTS PUSHING INTO THE CENTER OF THE COUNTRY BY SUNDAY. BESIDES A COOL START...THE WEEKEND LOOKS DRY...PARTLY CLOUDY...AND WARMER THAN THE COLD MIDWEEK AHEAD. BEYOND THE WEEKEND...THE RIDGE AXIS WILL PUSH OVER OUR AREA EARLY NEXT WEEK AND TEMPERATURES WILL CONTINUE TO WARM. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1221 AM CDT MON MAY 12 2014 RAIN WITH EMBEDDED TSTMS SPREAD ACROS ENTIRE COVERAGE AREA... ALTHOUGH BACK EDGE HAS ENTERED SWRN MN AND IS PROGRESSING NEWD. HAVE TRIED TO TIME THIS BACK EDGE ACRS ALL TAF SITES DURING THE FIRST PORTION OF THE 12/06Z TAF SET. CEILINGS HAVE STEADILY LOWERED...AND ONCE THE PRECIP ENDS...AM LOOKING FOR CIGS TO DROP INTO IFR RANGE DUE TO LOW LEVEL MOISTURE CAUSING LOW STRATUS DEVELOPMENT. WITH WINDS NOT GOING CALM...STAYING CLOSE TO 5 KT OVERNIGHT EVEN WHEN GOING VRBL IN ERN MN INTO WRN WI...NOT LOOKING FOR ANYTHING WORSE THAN MVFR VSBY. THERE LOOKS TO BE A SECOND BATCH OF -RA FOR LATE TMRW MRNG INTO TMRW AFTN. THERE ARE ENOUGH QUESTIONS REGARDING CONVECTIVE POTENTIAL SO HAVE OPTED TO OMIT ITS MENTION ATTM...BUT WILL ANALYZE LATEST MODELS AND DETERMINE IF CONVECTION NEEDS TO BE ADDED TO LATER TAFS. WINDS FROM THE E AND SE WILL GO VRBL ARND DAYBREAK THEN ALL SITES WILL SWING TO THE W AND NW THIS AFTN AND REMAIN THERE THRU THE EVE. SUSTAINED SPEEDS WILL INCRS TO 10-15 KT WITH GUSTS NEAR 25 KT THIS AFTN AND EVE BEFORE SLIGHTLY DIMINISHING THIS EVE. KMSP...VFR CONDS TO START DESPITE WIDESPREAD -RA WITH A FEW TSRA...MAINLY S AND E OF MSP. STILL MAY BE POCKETS OF MOD/HVY RAIN IN THE FIRST COUPLE OF HRS THAT WILL DROP VSBY INTO IFR RANGE. ONCE THE RAIN EXITS...LOW STRATUS WITH MVFR VSBY WILL PREVAIL FOR THE REST OF THE EARLY MRNG HRS THRU ARND NOON. THEN THE NEXT BATCH OF RAIN WILL PUSH THRU...SLIGHTLY IMPROVING CONDITIONS AS THE RAIN HELPS WASH OUT SOME OF THE LOW LEVEL MOISTURE. AFTER THIS BATCH...THEN THE IFR CEILINGS ARE EXPECTED TO REDEVELOP. THAT SAID...CEILINGS SUB-1700 FT WILL LIKELY PREVAIL FOR MUCH OF THE TAF PERIOD STARTING OVERNIGHT AND PERSISTING THRU THE REST OF THIS TAF PERIOD. /OUTLOOK FOR KMSP/ TUE...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 15-20 KTS. WED...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 5-15 KTS. THU...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS NW 5-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...RAH LONG TERM...SPD AVIATION...JPC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1240 AM CDT MON MAY 12 2014 .UPDATE... ISSUED AT 1221 AM CDT MON MAY 12 2014 UPDATED TO INCLUDE 06Z AVIATION DISCUSSION BELOW. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 355 PM CDT SUN MAY 11 2014 EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH RAP 500MB HEIGHTS AND WINDS IDENTIFIED A VIGOROUS SHORTWAVE ROTATING OVER THE 4-CORNERS REGION...WITH AN MCS ONGOING IN EASTERN IA. VISIBLE SATELLITE SHOWED CLEARING BEHIND THIS MCS...AND THE SURFACE OBS HAVE ALREADY REFLECTED THE BOUNDARY LAYER DESTABILIZATION AS TEMPERATURES HAVE INCREASED 5DEG/HR BUT KEPT THE EASTERLY COMPONENT IN THE WIND FIELD. THIS WIND SHIFT MARKED THE STOUT FRONTAL BOUNDARY WHICH WILL BE THE FOCUS FOR TORNADOES LATER THIS AFTERNOON ACROSS EASTERN NE AND WESTERN IA. TEMPERATURES WERE IN THE MID 80S SOUTH OF THIS WARM FRONT WITH SOUTHERLY WINDS...WHILE NORTH OF THE WARM FRONT TEMPERATURES WERE IN THE LOW TO MID 70S WITH DEWPOINTS IN THE MID 60S. THE MLCAPE GRADIENT MIRRORED THE POSITION OF THE EAST/WEST ORIENTED WARM FRONT...BUT INSTABILITY WAS BUILDING WELL NORTH OF THE FRONT AS EVIDENT BY THE 3HR SBCAPE CHANGE ON THE SPC MESOANALYSIS PAGE. THE FINAL POSITION OF THE WARM FRONT WILL DICTATE WHERE THE SURFACE BASED STORMS ARE...AND THUS THE BEST THREAT FOR TORNADOES. AT THIS TIME IT APPEARS THAT THE THREAT WILL REMAIN WELL SOUTH OF THE CWA. HOWEVER...THE LAST FEW RUNS OF THE HRRR AND HOPWRF INDICATE THAT A FEW ELEVATED STORMS ARE EXPECTED AFTER 00Z ACROSS THE SOUTHERN PART OF THE FORECAST AREA. THESE STORMS WILL HAVE 1000-1500J/KG OF MUCAPE TO WORK WITH DEEP SHEAR FAVORABLE FOR ORGANIZED CONVECTION. A FEW STORMS WILL HAVE THE POTENTIAL FOR PRODUCE SEVERE HAIL...MAINLY ALONG THE I-90 CORRIDOR. HEAVY RAIN IS ALSO A THREAT...PERHAPS MORESO THAN THE SEVERE WEATHER. AT THIS TIME...IT APPEARS THAT THE HEAVIEST RAINFALL WILL FALL JUST SOUTH AND EAST OF THE FORECAST AREA ALONG A LINE FROM OMAHA TO LA CROSSE WI. IT IS WITHIN THIS LINE THAT A HP SUPERCELLS ARE EXPECTED WHICH WILL BE CAPABLE OF PRODUCING 2-3IN/HR RAINFALL RATES AND FLASH FLOODING GIVEN THE RAINFALL THAT OCCURRED EARLIER THIS MORNING. IN OUR CWA...WE DID NOT HAVE THE MORNING RAINFALL...AND SUPERCELLS APPEAR LESS LIKELY...SO ALTHOUGH WE MAY GET A QUICK 1-2 INCHES OF RAIN WITH A FEW OF THE HEAVIER CELLS...THIS IS ABOVE FLASH FLOOD GUIDANCE. THEREFORE HAVE OPTED TO HOLD OFF ON A FLOOD WATCH FOR NOW. TO TIE BACK INTO THE HIRES MODELS...THE PROGRESSIVE NATURE OF THE EASTWARD MOVING STORMS ALSO SUPPORTS NOT ISSUING A FLOOD WATCH. THERE WILL BE A LULL IN THE PRECIP ACROSS CENTRAL MN AS THE SURFACE LOW TRACKS NORTHEASTWARD OVERNIGHT. MEANWHILE LIGHT RAIN WILL CONTINUE ACROSS THE WESTERN CWA IN THE DEFORMATION AREA OF THE UPPER LEVEL WAVE. FORECAST MODELS SHOW THE POTENTIAL FOR SOME CONVECTION REDEVELOPING IN THE WARM SECTOR OF THE SURFACE LOW ACROSS EASTERN MN AND WESTERN WI...SO TRIED TO REFLECT THAT IN THE AFTERNOON POP GRIDS. THESE STORMS DO HAVE THE POTENTIAL TO BE SEVERE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 355 PM CDT SUN MAY 11 2014 NOT MUCH IN THE WAY OF CHANGE TO THE EXTENDED PORTION OF THE FORECAST...WITH THE UPCOMING WEEK BEING MARKED BY COOL TEMPERATURES AND PERIODIC SCATTERED LIGHT SHOWERS AS A DEEPLY AMPLIFIED LONGWAVE TROUGH PIVOTS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGIONS. THE BEGINNING OF THE LONG TERM PERIOD /MONDAY NIGHT/ WILL FEATURE RAIN SHOWERS WINDING DOWN AS THE LOW LIFTS TO LAKE SUPERIOR. ADDITIONAL RAINFALL AMOUNTS SHOULD BE AROUND A COUPLE TENTHS OF AN INCH OR LESS. TUESDAY THROUGH FRIDAY BRINGS CYCLONIC FLOW WITH COOLER THAN NORMAL TEMPERATURES AND THE POTENTIAL FOR OCCASIONAL SCATTERED SHOWERS AS THE TROUGH BLANKETS THE REGION. HIGHS WILL BE IN THE 50S AND LOWS WILL DIP INTO THE LOWER 30S AND 40S. THE POTENTIAL FOR FROST LOOKS TO BE TUESDAY THROUGH THURSDAY NIGHTS. TEMPERATURES MODERATE NEXT WEEKEND AS WESTERN UPPER RIDGING BUILDS INTO THE CENTRAL CONUS. HIGHS IN THE 60S LOOK LIKE A GOOD BET FOR NEXT WEEKEND...ALTHOUGH A FEW SHOWERS MAY BE LURKING ON SUNDAY IF THE ECMWF SOLUTION VERIFIES /WHICH INDICATES A TROUGH WILL BUST IN FROM THE PACIFIC NORTHWEST AND BREAK DOWN THE RIDGE/. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1221 AM CDT MON MAY 12 2014 RAIN WITH EMBEDDED TSTMS SPREAD ACROS ENTIRE COVERAGE AREA... ALTHOUGH BACK EDGE HAS ENTERED SWRN MN AND IS PROGRESSING NEWD. HAVE TRIED TO TIME THIS BACK EDGE ACRS ALL TAF SITES DURING THE FIRST PORTION OF THE 12/06Z TAF SET. CEILINGS HAVE STEADILY LOWERED...AND ONCE THE PRECIP ENDS...AM LOOKING FOR CIGS TO DROP INTO IFR RANGE DUE TO LOW LEVEL MOISTURE CAUSING LOW STRATUS DEVELOPMENT. WITH WINDS NOT GOING CALM...STAYING CLOSE TO 5 KT OVERNIGHT EVEN WHEN GOING VRBL IN ERN MN INTO WRN WI...NOT LOOKING FOR ANYTHING WORSE THAN MVFR VSBY. THERE LOOKS TO BE A SECOND BATCH OF -RA FOR LATE TMRW MRNG INTO TMRW AFTN. THERE ARE ENOUGH QUESTIONS REGARDING CONVECTIVE POTENTIAL SO HAVE OPTED TO OMIT ITS MENTION ATTM...BUT WILL ANALYZE LATEST MODELS AND DETERMINE IF CONVECTION NEEDS TO BE ADDED TO LATER TAFS. WINDS FROM THE E AND SE WILL GO VRBL ARND DAYBREAK THEN ALL SITES WILL SWING TO THE W AND NW THIS AFTN AND REMAIN THERE THRU THE EVE. SUSTAINED SPEEDS WILL INCRS TO 10-15 KT WITH GUSTS NEAR 25 KT THIS AFTN AND EVE BEFORE SLIGHTLY DIMINISHING THIS EVE. KMSP...VFR CONDS TO START DESPITE WIDESPREAD -RA WITH A FEW TSRA...MAINLY S AND E OF MSP. STILL MAY BE POCKETS OF MOD/HVY RAIN IN THE FIRST COUPLE OF HRS THAT WILL DROP VSBY INTO IFR RANGE. ONCE THE RAIN EXITS...LOW STRATUS WITH MVFR VSBY WILL PREVAIL FOR THE REST OF THE EARLY MRNG HRS THRU ARND NOON. THEN THE NEXT BATCH OF RAIN WILL PUSH THRU...SLIGHTLY IMPROVING CONDITIONS AS THE RAIN HELPS WASH OUT SOME OF THE LOW LEVEL MOISTURE. AFTER THIS BATCH...THEN THE IFR CEILINGS ARE EXPECTED TO REDEVELOP. THAT SAID...CEILINGS SUB-1700 FT WILL LIKELY PREVAIL FOR MUCH OF THE TAF PERIOD STARTING OVERNIGHT AND PERSISTING THRU THE REST OF THIS TAF PERIOD. /OUTLOOK FOR KMSP/ TUE...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 15-20 KTS. WED...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 5-15 KTS. THU...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS NW 5-15 KTS. && .HYDROLOGY... ISSUED AT 355 PM CDT SUN MAY 11 2014 AT THIS TIME RIVER FLOODING APPEARS TO BE THE PRIMARY CONCERN MAINLY IN WESTERN WI AND THE MAINSTEM OF THE MISSISSIPPI RIVER. ANOTHER ROUND OF 1 TO 2 INCHES OF BASIN-WIDE RAINFALL IS EXPECTED OVER THE NEXT 24 HRS. AT THIS TIME...THE THREAT FOR THE HEAVIEST RAIN AND FLASH FLOODING APPEARS TO BE ACROSS IOWA...SO NOT ANTICIPATING ANY FLASH FLOODING IN MN OR WI. IF IT WERE TO HAPPEN...IT WOULD BE IN FAR SOUTHERN MN. LASTLY, IF THE FORECAST RAINFALL AMOUNTS TREND HIGHER THAN CURRENTLY EXPECTED...THE FLOODING POTENTIAL WILL INCREASE AS WELL. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE...JPC SHORT TERM...JRB LONG TERM...LS AVIATION...JPC
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
346 AM CDT Mon May 12 2014 .SHORT TERM: (Today and Tonight) Issued at 330 AM CDT Mon May 12 2014 Main forecast issues for today are the probability of thunderstorms and any severe potental, as well as just how warm it may get. Current thinking is there should be a gradual upswing in convection as the day progresses, primarily during the later half of the afternoon. It appears that northeast Missouri will be the area we will have to watch most closely through mid morning. Two things to key an eye on - an outflow boundary pushing southeastward across eastern Iowa as a focus for additional thunderstorms, and also a cluster of thunderstorms across eastern Kansas just southwest of Kansas City and if they will hold together as they move northeastward. Otherwise I think that there will be a general decrease in the convective cloud debris during the morning, which given the mild early morning temperatures should allow for a quick warm-up by early afternoon. The convection allowing models and more specifically the HRRR is suggesting that by mid morning, isolated showers or thunderstorms could develop just about anywhere within the CWA, but most favored across southeast Missouri and southern Illinois. The main action still looks like the later half of the afternoon. The warm sector air mass ahead of the cold front will become quite unstable by mid-late afternoon with SBCAPE in excess of 2000 J/KG and little CIN. Expecting numerous thunderstorms to develop across western Missouri into central and northeast Missouri. Deep layer shear of 20-30 kts and the anticipated CAPE would support a few severe storms capable of large hail and damaging winds from the afternoon into about mid-evening. The front moves through all but the far eastern sections of the CWA tonight accompanied by widespread showers and thunderstorms and ushering much cooler air into the region in its wake. It also appears that there will be an increasing amount of post-frontal showers overnight immediately in the cool air in response to large scale forcing. Glass .LONG TERM: (Tuesday through Sunday) Issued at 330 AM CDT Mon May 12 2014 This marks the beginning of a cooler than normal period with a slow-moving and deep upper trof dominating the region through the week. The front will quickly exit the remainder of the CWA early Tuesday morning with post-frontal showers impacting eastern Missouri and southwest Illinois in the morning and exiting by early-mid afternoon. Highs on Tuesday will be around 20 degrees cooler than today. A strong short-wave and possibly upper low will then migrate through the base of the deep trof from the southern Plains and into the mid MS valley Tuesday night-Wednesday night. More reminiscent of Fall or early Spring, large scale ascent with this system should produce a large area of showers or rain spreading into the area late Tuesday night into Wednesday. Its northward extent and longevity is all dependent on the strength of the system, and NAM featuring a closed low and large deformation zone, has the greatest northward push and keeps precipitation well into Wednesday night. Regardless the precipitation and accompanying overcast low clouds will keep temperatures well below average on Wednesday. We could continue to see a periodic shower threat through the end of the week as we get into deeper cyclonic flow on the backside of the slow-moving deep upper trof. Temperatures will remain below average into at least Friday. Glass && .AVIATION: (For the 06z TAFs through 06z Monday Night) Issued at 1136 PM CDT Sun May 11 2014 Expecting VFR flight conditions to prevail across most of the area for the rest of the night. Low level wind shear conditions will spread further than previously thought; probably as far east as southwest Illinois. Have included LLWS in all terminal forecasts. Thunderstorms over Iowa are trying to spread a bit further south into northern Missouri, however most guidance agrees that storms will be weakening as they get far enough east to threaten our area. Some widely scattered showers or storms may develop as diurnal heating increases during the late morning or early afternoon, but the primary threat for thunderstorms will be during the late afternoon and evening ahead of the cold front. Guidance seems to be in good agreement that there will be a line of storms marching eastward from western Missouri in the afternoon, reaching eastern Missouri by early evening. With these high precipitation chances in guidance, feel it`s ok to go ahead and star TEMPOs in the terminal forecasts. Specifics for KSTL: VFR flight conditions are expected to continue at Lambert tonight. Low level wind shear looks to spread further east than previously forecast with 45kt or higher winds around 1500-2000ft, so have included it until 12Z. The guidance suite seems to be in good agreement that the storms over Iowa won`t spread south to affect Lambert through the morning, but there may be some widely scattered showers or storms developing during the late morning or early afternoon. Think coverage will be pretty low though so have not mentioned it in this update. The primary threat for thunderstorms will come during the early evening ahead of a cold front. While timing is still uncertain, it looks very likely that Lambert will receive a period of thunderstorms in the early evening followed by lighter rain later in the evening/overnight. Carney && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
130 AM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE OFFSHORE WILL MAINTAIN WELL ABOVE NORMAL TEMPERATURES THROUGH THE MIDDLE OF THE UPCOMING WEEK. A COLD FRONT WILL APPROACH THURSDAY BEFORE CROSSING OFFSHORE ON FRIDAY...BRINGING A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS. COOLER TEMPERATURES WILL DEVELOP IN THE WAKE OF THIS COLD FRONT INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1045 PM SUNDAY...RIDGING ALOFT AND ITS AXIS NEARLY OVERHEAD...WILL AMPLIFY-SOME ACROSS THE BI-STATE REGION OVERNIGHT AND INTO THE SHORT TERM PERIOD. THIS WILL DEFLECT ANY S/W TROFS ALOFT TO THE WEST AND NORTH OF THE FA. AT THE SFC...MODEST HIGH PRESSURE CENTERED OFFSHORE AND EAST OF THE CAROLINAS...WILL RIDGE BACK ACROSS THE REGION...AND PREVAIL GOING INTO THE SHORT TERM PERIOD. FOR THE REMAINDER OF THIS EVENING AND OVERNIGHT...THE DIURNALLY INDUCED CONVECTION HAS DISSIPATED LEAVING A FEW OUTFLOW BOUNDARIES ACROSS PORTIONS OF THE FA GOING INTO DAYLIGHT MONDAY. WITH THE MAJORITY OF THE LEFTOVER CONVECTIVE CLOUDINESS DISSIPATING...A SFC BASED INVERSION SHOULD DEVELOP COURTESY OF THE HOURLY NAMBUFR SOUNDINGS. LOW LEVEL STRATUS BELOW 1K FEET WILL DEVELOP ACROSS THE FA VIA LATEST HRRR MODEL RUNS. MIN TEMPS HAVE BEEN MASSAGED UPWARDS ESPECIALLY WITH LOW LEVEL STRATUS OVERTAKING THE FA AND SFC DEWPOINTS REMAINING WELL INTO THE 60S ACROSS THE MAJORITY OF THE FA. PATCHY TO AREAS OF FOG WILL ALSO BE ADVERTISED ACROSS THE FA...FOR MAINLY THE HOURS BETWEEN MIDNIGHT TO JUST AFTER SUNRISE. COULD BE ONE OF THOSE NIGHTS WHERE LOW LEVEL STRATUS AND FOG DUEL WITH ONE ANOTHER IN SEEING WHO WILL PREVAIL OVER THE OTHER. PREVIOUS DISCUSSION............................................ AS OF 300 PM SUNDAY...ISOLATED TO WIDELY SCATTERED SHOWERS ARE BREAKING OUT ACROSS THE FORECAST AREA EARLY THIS AFTERNOON. SO FAR HAVE NOTED ONLY ONE BRIEF THUNDERSTORM OVER COASTAL GEORGETOWN COUNTY. WITH A MODERATELY UNSTABLE ATMOSPHERE AND MOIST LOW LEVELS EXPECT THIS ACTIVITY TO CONTINUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY EVENING. BOTH GFS AND NAM INDICATE COLUMN MOISTURE BECOMING MORE SHALLOW AFTER SUNSET AND WITH AN UPPER RIDGE BUILDING IN SEE LITTLE CHANCE FOR SIGNIFICANT OVERNIGHT PRECIPITATION. SO...AS THIS ACTIVITY SEEMS DIURNALLY DRIVEN WITH NO STRONG FORCING MECHANISM PRESENT...EXPECT CONVECTION TO FADE WITH THE SETTING SUN AND TO BE OVER WITH BY MIDNIGHT. HAVE CONTINUED RECENT TREND OF FORECASTING MINIMUM TEMPERATURES A FEW DEGREES ABOVE GUIDANCE. THIS METHOD HAS BEEN VERIFYING WELL AGAINST GUIDANCE RECENTLY AND GIVES US OVERNIGHT MINIMUMS IN THE MID 60S FOR MOST PLACES. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...SUMMERTIME PATTERN AMPLIFIES DURING THE BEGINNING OF THE WEEK THANKS TO A STRENGTHENING 5H RIDGE. THIS WILL DRIVE TEMPERATURES WELL INTO THE 80S TO AROUND 90 MONDAY AND TUESDAY AWAY FROM THE COAST...WITH LOW 80S ANTICIPATED AT THE BEACHES. THESE VERY WARM TEMPS...COMBINED WITH STILL COOL OCEAN TEMPS...AND A WEAK GRADIENT BOTH AT THE SURFACE AND ALOFT...SHOULD ALLOW DECENT INLAND PENETRATION OF THE SEA BREEZE BOTH DAYS. THIS WILL HAVE ONLY LIMITED IMPACT ON HIGHS THOUGH SINCE TEMPS WILL SOAR QUICKLY DURING LATE MORNING EARLY AFTN...THANKS TO LOWS ONLY FALLING INTO THE MID/UPR 60S...70 AT THE COAST. MORE QUESTIONABLE PORTION OF THE FORECAST INVOLVES CONVECTIVE POTENTIAL THROUGH EARLY WEEK. GUIDANCE IS STUBBORNLY DEPICTING SCATTERED SHOWERS/TSTMS BOTH MONDAY AND TUESDAY AFTNS...FOCUSED PRIMARILY ON THE SEA BREEZE. SPC HAS GENERAL RISK ACROSS THE AREA BOTH DAYS AS WELL. AM STRUGGLING TO FIND REASONS TO INCLUDE CONVECTION IN THE FORECAST...OTHER THAN DEWPOINTS WELL INTO THE 60S AND STEEP SURFACE-BASED LAPSE RATES. HOWEVER...PRETTY MUCH EVERYTHING ELSE POINTS TO THE NEXT TWO DAYS BEING DRY. 500MB RIDGE AXIS SITS NEARLY OVERHEAD...PROVIDING A SUBSIDENT LID WITH VERY WEAK MID-LEVEL LAPSE RATES. 700MB RIDGE REMAINS ANCHORED OVERHEAD AS WELL...FORCING ANY MOISTURE AROUND TO THE WEST OF THE AREA...WHICH IS ALSO ECHOED BY WEAK 850-700MB MOISTURE TRANSPORT VECTORS AND DRYING FORECAST SOUNDINGS. LCL`S ARE AT THE TOP OF WHATEVER RESIDUAL MOIST LAYER EXISTS MONDAY AND TUESDAY...SO UPDRAFTS SHOULD SUFFER FROM SIGNIFICANT DRY AIR ENTRAINMENT...FURTHER LIMITING CONVECTIVE POTENTIAL. STILL...INHERITED HAS SCHC MONDAY AND SURROUNDING WFO`S HAVE AT LEAST THAT...SO WILL KEEP SCHC MONDAY FOR ISOLATED SHOWERS...BUT DROP POP TO SILENT ON TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...THE BIG WEATHER MAKER IN THE LONG TERM WILL BE AN EASTWARD-MOVING COLD FRONT THURSDAY...PUSHED ALONG BY A FULL LATITUDE UPPER TROUGH EXTENDING FROM HUDSON BAY TO THE GULF COAST. THE WESTERN EXTENSION OF THE BERMUDA HIGH WILL COVER THE AREA WEDNESDAY. RELATIVELY STABLE ONSHORE WINDS AND PLENTY OF DRY AIR ASSOCIATED WITH THE DEEP-LAYER RIDGING SHOULD KEEP THINGS MOSTLY SUNNY AND DRY WITH HIGHS IN THE UPPER 80S INLAND AND AROUND 80 ON THE BEACHES. PRESSURES WILL BEGIN TO FALL WEDNESDAY NIGHT AS THE AFOREMENTIONED FRONT CROSSES THE LOWER MISSISSIPPI VALLEY. INCREASING SOUTHERLY FLOW WILL BEGIN TO MOISTEN OUR AIRMASS...AND PRECIPITABLE WATER VALUES SHOULD CLIMB FROM AROUND 1 INCH WEDNESDAY TO 1.5 INCHES BY LATE WEDNESDAY NIGHT. INTEGRATED COLUMN MOISTURE PEAKS JUST AHEAD OF THE FRONT THURSDAY EVENING WITH PW VALUES NEAR 1.9 INCHES. 850 MB WINDS DO NOT BECOME PARTICULARLY STRONG...20-30 KT DEPENDING ON YOUR MODEL...AND KINEMATIC FIELDS ARE NOT OVERLY CONCERNING FOR A SEVERE WEATHER RISK. GIVEN MODEST FORECAST INSTABILITY (CAPE 1000-1500 J/KG) AND SUCH MOIST SOUNDINGS THE LARGEST CONCERN COULD BE LOCALLY HEAVY RAIN AND PERHAPS A WET DOWNBURST IN STRONGER CELLS. THE BULK OF THE LATEST OPERATIONAL MODEL RUNS SHOW THE COLD FRONT PUSHING ACROSS THE EASTERN CAROLINAS THURSDAY NIGHT...HOWEVER THE 12Z CANADIAN AS WELL AS ABOUT 25% OF THE 00Z & 06Z GFS ENSEMBLE MEMBERS ARE SLOWER MOVING THE BOUNDARY OFF THE COAST. I HAVE THEREFORE MAINTAINED A 30-40 POP INTO FRIDAY. DRY WEATHER SHOULD ALMOST CERTAINLY DEVELOP BY FRIDAY EVENING LASTING INTO SATURDAY AS HIGH PRESSURE BUILDS OVER THE CAROLINAS. THE MOST NOTABLE FEATURE ABOUT THIS INCOMING AIRMASS WILL BE HOW MILD TEMPERATURES WILL BE COMPARED TO WHAT WE HAVE EXPERIENCED THE PAST WEEK. WITH 850 MB TEMPS PROGGED +8C TO +10C BOTH FRIDAY AND SATURDAY...HIGHS SHOULD REMAIN IN THE UPPER 70S FOR MOST AREAS WITH LOWS IN THE 50S. BY NEXT SUNDAY BOTH THE GFS AND ECMWF SHOW THE TRAILING END OF A POTENT UPPER LEVEL DISTURBANCE MOVING ACROSS THE CAROLINAS. EVEN WITH NO LOW-LEVEL GULF OR ATLANTIC INFLOW...MODELS SHOW ENOUGH PACIFIC MOISTURE COMING ACROSS AT AND ABOVE 850 MB THAT A 30 POP FOR SHOWERS APPEARS WARRANTED. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...EXPECT IFR CIGS/VSBYS ACROSS THE CWA TONIGHT AS NEARLY CALM CONDITIONS PROMOTE FOG AND STRATUS. WIDESPREAD STRATUS AND SOME FOG WAS ALREADY OCCURRING ACROSS THE COASTAL TAF SITES...PRODUCING IFR OR LOWER CONDITIONS. WE EXPECT THESE SAME CONDITIONS WILL OVERSPREAD KLBT AND KFLO THROUGH 08Z. CONDITIONS SHOULD IMPROVE TO VFR BY 13Z OR SO...WITH LIGHT AND VRB WINDS EARLY BECOMING SOUTH AOB 10 KT IN THE AFTERNOON. FCST SOUNDINGS SHOW A LOT OF DRY MID-LEVEL AIR DURING THE DAY...SO CONVECTION SHOULD BE ISOLATED AT BEST AS DIURNAL CU BUILDS WITH DAYTIME HEATING. EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR FOG/STRATUS IS POSSIBLE THROUGH THURSDAY. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY. SHOWERS/TSTMS EXPECTED THURSDAY THROUGH EARLY FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM SUNDAY...ORIENTATION OF THE SFC RIDGE AXIS EXTENDING ACROSS THE AREA WATERS FROM THE HIGHS CENTER OFFSHORE AND EAST OF THE CAROLINAS...WILL DETERMINE WIND DIRECTIONS. AT THIS POINT...MODELS INDICATE WINDS BECOMING SW-WSW NORTH OF LITTLE RIVER INLET...AND S TO SSW SOUTH OF THIS INLET. THIS TO OCCUR AFTER THE DEMISE OF THE SEA BREEZE CIRCULATION. THE LOOSE SYNOPTIC SFC PRESSURE GRADIENT WILL KEEP WIND SPEEDS AT OR BELOW 10 KT. SIGNIFICANT SEAS WILL RUN 2 TO OCCASIONALLY 3 FT...AND MAINLY BE COMPRISED OF WIND DRIVEN WAVES WITH PERIODS OF 5 TO 6 SECONDS. AT THIS POINT...THE 11 TO 13 SECOND PERIOD EASTERLY GROUND SWELL REMAINS NEGLIGIBLE FOR ANY INPUT INTO THE SIGNIFICANT SEAS. PREVIOUS DISCUSSION.......................... AS OF 300 PM SUNDAY...MANAGEABLE MARINE CONDITIONS EXPECTED. EXPECT A LIGHT SW WIND FLOW ACROSS THE WATERS THROUGH TONIGHT. SEAS GENERALLY 2-3 FEET...IN A MIX OF SSW WAVES 1-2 FEET EVERY 4-5 SEC AND SE WAVES 1-2 FT EVERY 7-8 SECONDS. ISOLATED TSTMS ARE POSSIBLE NEAR SHORE THIS AFTERNOON INTO THIS EVENING...AND THE MOTION WILL BE FROM SW TO NE. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...PRIMARILY UNIFORM WIND/WAVE CONDITIONS DURING THE SHORT TERM AS BERMUDA HIGH PRESSURE SITS OFFSHORE INTO MID-WEEK. RETURN FLOW AROUND THIS HIGH PRODUCES SW WINDS OF 10-15 KTS DURING THE DAY...AND 5-10 KTS AT NIGHT. THE EXCEPTION WILL BE IN THE NEAR-SHORE WATERS WHERE A SEA BREEZE WILL CAUSE WINDS TO GUST UP TO 20 KTS FOR A FEW HOURS EACH AFTN/EVE. THESE WINDS COMBINED WITH THE LONG FETCH AROUND THE HIGH PRESSURE WILL BUILD SEAS TO 2-3 FT THROUGH THE PERIOD...WITH A 5 SEC S/SW WIND WAVE AND A 7 SEC SE GROUND SWELL COMPRISING THE SPECTRUM. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...HIGH PRESSURE JUST OFFSHORE WEDNESDAY SHOULD PROVIDE GENTLE ONSHORE WINDS AND DRY WEATHER. MOISTURE WILL INCREASE THURSDAY AHEAD OF A COLD FRONT...EXPECTED TO MOVE OFF THE COAST FRIDAY MORNING. THIS FRONT SHOULD BE PRECEDED BY WAVES OF SHOWERS AND EMBEDDED THUNDERSTORMS...ESPECIALLY LATE THURSDAY AFTERNOON INTO THURSDAY NIGHT. ONCE THE FRONT MOVES FARTHER OFFSHORE FRIDAY... CLEARING CONDITIONS ARE EXPECTED ALONG WITH BREEZY NORTH TO NORTHWEST WINDS. AT THIS TIME IT APPEARS CONDITIONS SHOULD REMAIN BELOW ADVISORY THRESHOLDS...ALTHOUGH WINDS BOTH AHEAD OF AND BEHIND THE FRONT COULD APPROACH 20 KNOTS SOUTHEAST OF CAPE FEAR WHERE SEA SURFACE TEMPERATURES ARE CURRENTLY HIGHEST. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH/REK SHORT TERM...JDW LONG TERM...TRA AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1214 AM CDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 347 PM CDT SUN MAY 11 2014 COMPLEX FORECAST CONTINUES THIS AFTERNOON INTO THE OVERNIGHT. CURRENT ANALYSIS SHOWS SURFACE LOW PRESSURE OVER WESTERN KANSAS. KIND OF A DUAL WARM FRONT SIGNATURE. WITH MAIN AND STRONGEST WARM FRONT ACROSS FAR SOUTHERN NEBRASKA INTO SOUTHWEST IOWA...WHICH WAS REINFORCED BY THE OVERNIGHT MCS. MODELS IN GOOD AGREEMENT WITH THE POSITION OF THIS FRONT...AND ALL GUIDANCE SUGGESTS IT WILL ONLY SLOWLY MOVE NORTH TODAY. THIS IS THE AREA...SOUTHEASTERN NEBRASKA INTO SOUTHWESTERN IOWA...AT GREATEST RISK FOR SEVERE WEATHER AND TORNADOES...AS HIGHLIGHTED BY THE SPC OUTLOOK. FURTHER NORTH WE HAVE A SECONDARY WARM FRONT RUNNING FROM THE TRIPLE POINT OVER SOUTHERN NEBRASKA...NORTHEAST TO JUST SOUTH OF STORM LAKE. MARGINAL SURFACE INSTABILITY IS BEGINNING TO FORM IN THIS AREA...ALTHOUGH MOST OF IT IS REMAINING SOUTH OF OUR CWA. ALSO LARGE SCALE LIFT INCREASING ON THE NOSE OF A PV WAVE IS HELPING TO TRIGGER ELEVATED SHOWERS AND THUNDERSTORMS ACROSS THE NORTHWEST HALF OF THE CWA. THESE SHOULD STAY BELOW SEVERE LIMITS AND PUSH NORTH OF THE AREA BY THIS EVENING. DAYTIME HEATING AND INCREASING FORCING HAS ALSO HELPED FIRE CONVECTION ACROSS SOUTH CENTRAL NEBRASKA. THE STRONGEST SURFACE BASED SUPERCELLS WILL LIKELY RIDE FROM NEAR THE SOUTHERN WARM FRONT TO THE SECONDARY WARM FRONT...AND THUS STAY SOUTH OF OUR CWA. ALTHOUGH WILL NEED TO WATCH AREAS FROM SIOUX CITY TO STORM LAKE. LOW LEVELS REMAIN STABLE...BUT ENOUGH DESTABILIZATION IS POSSIBLE FOR STORMS MOVING INTO THIS AREA TO TAP INTO THE NEAR SURFACE LAYER. IF THIS HAPPENED AN ISOLATED TORNADO WOULD BE POSSIBLE. WHILE THIS STILL SEEMS TO BE A LOW THREAT...IT IS NOT IMPOSSIBLE AND WILL NEED TO MONITOR TRENDS. SEEMS MORE LIKELY THAT STORMS THAT FORM AND MOVE INTO OUR CWA WILL STAY ELEVATED...BASED ABOVE THE LOW LEVEL STABLE LAYER. DECENT ELEVATED INSTABILITY SHOULD INCREASE AND COULD MAKE IT ALL THE WAY TO ALMOST THE JAMES RIVER. QUESTION IS HOW MUCH MOISTURE WE CAN GET ADVECTED INTO THE CWA...WITH THE CONVECTION TO OUR SOUTH HAMPERING THIS TO A DEGREE. SEEMS LIKE A GOOD BET THAT NORTHWEST IOWA AND SOUTHWEST MINNESOTA WILL GET INTO THE ACTION...LESS CERTAIN FURTHER NORTHWEST. WITH THE ELEVATED WARM FRONT WELL TO OUR NORTH...EVEN PARCELS LIFTED FROM NEAR 750 MB SHOULD HAVE AROUND 40 KTS OF SHEAR TO WORK WITH. SO THOUGHT IS ELEVATED SUPERCELLS WILL BE POSSIBLE IF WE CAN GET THE MOISTURE AND ELEVATED INSTABILITY INTO THE AREA. MAIN THREAT WOULD BE LARGE HAIL WITH ANY STORM. AGAIN HIGHEST SEVERE THREAT SHOULD BE ACROSS NORTHWEST IOWA AND ADJACENT AREAS OF SOUTHWEST MINNESOTA WHERE CONFIDENCE IS HIGHEST ON INSTABILITY...THREAT IS MORE CONDITIONAL TOWARDS INTERSTATE 29. DO LIKE THE HRRR IDEA OF PUSHING EVERYTHING EAST BY LATER THIS EVENING AS STORMS ORGANIZE AND HELP PUSH THE FRONT EATS OF THE CWA. STILL COULD BE SOME SCATTERED SHOWERS...BUT MOST OF THE OVERNIGHT MAY END UP FREE OF HEAVY RAIN. ANOTHER PUSH OF THETAE ADVECTION LATE TONIGHT INTO EARLY MONDAY AS THE WHOLE SYSTEM BEGINS MOVING NORTHEAST. PRETTY GOOD LARGE SCALE LIFT TOO AS A STRONG JET ROUNDS THE BASE OF THE TROUGH. THUS THINKING PRECIPITATION COVERAGE WILL RAPIDLY INCREASE LATER TONIGHT INTO TOMORROW. MOST OF THIS WEST OF THE JAMES RIVER WILL BE MORE STABLE SHOWERY PRECIPITATION. DOES LOOK LIKE ELEVATED INSTABILITY WILL REMAIN TO THE EAST...THUS SHOULD GET SOME THUNDER OUT OF THE ACTIVITY. MAYBE EVEN SOME MARGINALLY SEVERE HAIL LATE TONIGHT INTO MONDAY MORNING GIVEN THE WIND PROFILES IF ENOUGH INSTABILITY IS PRESENT. ANY SURFACE BASED SEVERE WEATHER SHOULD STAY EAST OF THE CWA. SO OVERALL MONDAY LOOKS LIKE A PRETTY WET DAY WITH HIGHS IN THE 40S AND 50S. WINDS WILL BE ON THE INCREASE AS WELL...WITH AROUND 35 KTS AT 925 MB. WILL BE VERY CLOSE TO WIND ADVISORY CRITERIA ALONG AND WETS OF THE JAMES RIVER...WITH GUSTS APPROACHING 40 KTS. GIVEN EXPECTED WEAK MIXING DUE TO THE RAIN AND MARGINAL WINDS ALOFT...WILL HOLD OFF ON AN ADVISORY FOR NOW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 347 PM CDT SUN MAY 11 2014 IN THE LONGER TERM...THE WEATHER IS HIGHLIGHTED BY MUCH BELOW NORMAL TEMPERATURES FOR A BULK OF THE UPCOMING WEEK. FOR MONDAY NIGHT...DECIDED TO RAISE POPS TO A LOW END LIKELY CATEGORY IN SOME OF OUR WESTERN ZONES. ALTHOUGH THE GFS IS DRY BY MONDAY EVENING... THE HIGHER RESOLUTION MODELS DO HANG BACK DEEPER RESIDUAL MOISTURE IN OUR FORECAST AREA...ESPECIALLY FOR LOCATIONS WEST OF I 29. IN ADDITION...BOTH THE NAM AND GFS SHOW TROWALING MONDAY EVENING IN THE 305-315K LAYER. STILL...RAINFALL WILL BE LIGHT EVEN IN OUR WESTERN ZONES...WITH OUR EASTERN ZONES NOT SEEING MUCH OF A RAINFALL POTENTIAL. ALTHOUGH COOL...THE CLOUD COVER AND WIND WILL HELP OUR LOWS FROM PLUMMETING TOO FAR MONDAY NIGHT WITH READINGS MOSTLY A COUPLE OF DEGREES EITHER SIDE OF 40. THEN THE UPPER LOW BEGINS TO MEANDER ACROSS SOUTHERN CANADA AND THE NORTHERN MS VALLEY ALL THE WAY FROM TUESDAY THROUGH THURSDAY... EVENTUALLY LIFTING INTO THE WESTERN GREAT LAKES BY FRIDAY. THEREFORE VERY CHILLY WEATHER FOR THIS TIME OF YEAR WILL FOLLOW SUIT. EVEN THE BIAS CORRECTED TEMPERATURES ARE NOW COLD...AND THEY HAVE BEEN THE BEST RECENTLY IN OUR FORECAST AREA IN CAPTURING WARM... MIXED OUT TEMPERATURES DURING THE DAYTIME. INSTABILITY CU WILL POP ON TUESDAY WITH A STRONG UPPER CYCLONIC FLOW EXISTING...WITH A SMALL CHANCE FOR LIGHT SHOWERS AROUND BROOKINGS AND SOUTHWEST MN. AFTER SUNSET...SKIES WILL CLEAR TUESDAY NIGHT FOLLOWED BY SOME MORE INSTABILITY DAYTIME CU ON WEDNESDAY...AND THERE ARE STRONG INDICATIONS THAT A SHORT WAVE WILL DIVE DOWN THE NORTHWEST FLOW ALOFT GIVING THE POSSIBILITY OF MORE WIDELY SCATTERED LIGHT SHOWERS ACROSS THE ENTIRE FORECAST AREA. BUT LOW POPS ARE STILL WARRANTED AS A QUESTION EXISTS AS TO HOW MUCH OF THIS RAINFALL WILL ACTUALLY MEASURE. ULTIMATELY...THIS SHORT WAVE WILL REINFORCE THE PARENT UPPER LOW AND KEEP OUR CYCLONIC FLOW GOING WITH A FEW SHOWERS AGAIN POSSIBLE ON THURSDAY. AS MENTIONED ABOVE...TUESDAY THROUGH THURSDAY WILL BE COLD WITH HIGHS ONLY IN THE 50S TO AROUND 60. FURTHERMORE...MIXED LAYER WINDS ARE STOUT ON TUESDAY PROMISING BREEZY CONDITIONS...LESS SO ON WEDNESDAY BUT STILL THE WIND WILL BE STRONG ENOUGH TO GIVE A RATHER RAW DAY. ONE THING TO WATCH FOR BOTH TUESDAY NIGHT AND WEDNESDAY NIGHT AS SKIES CLEAR AFTER SUNSET AND WINDS SUBSIDE...IS THE POSSIBILITY OF FROST HERE AND THERE. DID NOT PUT THEM IN THE GRIDS YET...AND CERTAINLY DID NOT ISSUE ANY FROST HEADLINES. BUT SOME OF OUR LOWS DO FALL INTO THE MID 30S SO WOULD NOT BE SURPRISED TO SEE SOME LIGHT FROST IN LOW LYING AREAS. FURTHER OUT FRIDAY THROUGH SUNDAY...THE UPPER LOW FINALLY MOVES INTO THE GREAT LAKES...THE NORTH OF THE GREAT LAKES ALLOWING THE FLOW TO BECOME QUASI ZONAL. THERE MAY BE SOME WARM AIR ADVECTION SHOWERS ON SUNDAY AS THE NEXT UPPER TROUGH BEGINS TO DIG DOWN THE WESTERN U.S. COAST. THEREFORE HIGHS WILL FINALLY WARM UP INTO THE 60S FRIDAY THROUGH SUNDAY WITH LOWS ALSO MODERATING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1204 AM CDT MON MAY 12 2014 WIDESPREAD SHOWERS AND STORMS HAVE MOVED EAST OF THE AREA...HOWEVER COULD SEE AN ADDITIONAL CLUSTER OF SHOWERS AND STORMS MOVE ACROSS OUR FAR SOUTHEAST COUNTIES...INCLUDING KSUX THROUGH AROUND 09Z. ANOTHER BAND OF RAINFALL IS EXPECTED TO LIFT ACROSS SOUTHEAST SOUTH DAKOTA...WITH MORE SCATTERED COVERAGE INTO SOUTHWEST MINNESOTA AFTER 07Z. ALONG WITH OCCASIONAL RAINFALL...MVFR TO IFR CEILINGS ARE EXPECTED TO SPREAD NORTHEAST...BECOMING WIDESPREAD OVERNIGHT. THESE CEILINGS WILL STICK AROUND THROUGH THE DAY ON MONDAY AND COULD BEGIN LIFTING ACROSS THE WEST AFTER 00Z TUESDAY...POSSIBLY ALSO NEAR THE MISSOURI VALLEY...INCLUDING KHON AND KSUX. WINDS WILL BE GUSTY FROM THE NORTHWEST THROUGHOUT THE PERIOD...AVERAGING 15 TO 25 KT WITH GUSTS AS HIGH AS 35 KT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...MJ AVIATION...
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
442 AM CDT MON MAY 12 2014 .SHORT TERM... (Today and Tonight) WV imagery this morning was showing and a strong upper level trough over the central and southern Rockies with a mid level speed max of 50 to 70 knots rotating out in the Plains. Upper level flow has backed to southwest over Texas. Also, a lot mid and upper subsidence evident which is still resulting in a strong cap over West Central Texas. At the surface, a cold front was located along a Quanah to Seminole line. A dryline extended south along a Wink to Sanderson line. Not much happening yet convection wise as low level inhibition and cap is still holding strong. A few showers have developed just behind the cold front across northwest Texas. The airmass was very moist across our area with southerly flow and dewpoints in the mid to upper 60s. For today, the chance of showers and thunderstorms will increase mid morning through the afternoon across mainly the eastern half of the CWFA. The cold front will continue southeast into West Central Texas and will probably slow its forward speed. Scattered showers and thunderstorms will develop along and behind the front as elevated instability erases the cap. The HRRR convective allowing model is showing best coverage of activity east of an Abilene to San Angelo line. The combination of good instability in the warm sector and weak 0-6KM shear of 25 to 30 knots will result in multicell storms with possible brief supercell structures. A few strong to severe storms are possible across mainly the Heartland and Northwest Hill Country. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning. Going with mainly chance to slight chance POPS for today. Temperatures will be cooler with highs in the 80s. For tonight, There will be a chance of showers thunderstorms across much of our area with better coverage of storms east of a Coleman to Sonora line. a few storms may be severe. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning mainly before 06Z Tuesday. The bigger focus will be the potential for locally heavy rainfall across the Heartland and Northwest Hill Country, due to good low level southerly flow. moisture flux convergence along a slow moving cold front, PWAT values of 1.5 to 1.75 inches and in the RRQ of highly amplified 250MB jet. Rainfall amounts of 1 to 2 inches with locally heavy amounts are possible along and east of a Brownwood to Junction line. Also, going with LKLY to CAT POPS across the southeast CWFA. .LONG TERM... (Tuesday through next Monday) The cold front will be well south of the area early Tuesday morning, with the upper level trough axis over New Mexico. Showers and thunderstorms may be ongoing across far southeast sections early Tuesday morning but will move east of the area by mid to late morning. Additional showers and isolated thunderstorms will be possible across much of the area during the day as lift increases ahead of the approaching upper trough. Moisture will be limited, so precipitation is expected to be light, with most areas seeing one tenth inch or less of rainfall. It will be considerably cooler on Tuesday with highs well below normal for this time of year. NAM guidance looks too cool with highs in the upper 50s, so went with a GFS/NAM blend, which looks more reasonable with highs topping out in the lower 60s. Lingering showers will be possible Tuesday evening over southeast sections, otherwise dry conditions are expected overnight with clearing skies, as drier air filters in behind the departing upper trough. Temperatures will be very chilly Wednesday night with overnight lows in the lower and middle 40s. Dry and cool weather will continue on Wednesday with sunny skies, light winds and highs in the lower 70s. Another cool night is in store Wednesday night with low temperatures again in the 40s. Will maintain a dry forecast Thursday into next weekend with a warming trend through the period. Northwest flow aloft is expected through Saturday, with a short wave ridge overspreading the Plains on Sunday. High temperatures will warm from the mid 80s late week, to the upper 80s and lower 90s by the end of the weekend. Expect overnight lows in the 50s, warming into the 60s through the period. && .FIRE WEATHER... Elevated fire weather conditions will be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 80 50 63 45 72 / 40 20 20 10 0 San Angelo 86 52 62 43 73 / 30 20 20 10 0 Junction 85 57 64 46 73 / 50 70 40 20 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21/24
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
437 AM CDT MON MAY 12 2014 .DISCUSSION... THE POTENT UPPER LEVEL LOW OVER THE FOUR CORNERS THAT WAS RESPONSIBLE FOR SNOW IN DENVER YESTERDAY WILL EJECT NORTHEAST OUT INTO THE PLAINS TODAY...BUT ADDITIONAL UPPER ENERGY WILL DROP INTO THE BASE OF A DEEPENING LONGWAVE TROUGH TODAY. THIS UPPER TROUGH WILL ENGULF THE CENTRAL US BY TOMORROW...A PATTERN THAT IS VERY UNUSUAL FOR MID MAY. THIS SYSTEM HAS TAPPED INTO A CANADIAN AIRMASS AND HAS SENT AN UNSEASONABLY STRONG COLD FRONT BARRELING SOUTH. AT 4AM...THIS FRONT WAS LOCATED JUST SOUTH OF LUBBOCK TO NEAR VERNON TO EL RENO OKLAHOMA AND WAS MOVING SOUTHEAST AT 15 TO 20MPH. THE FRONT IS AHEAD OF MOST MODEL PROJECTIONS...WHICH IS NOT SURPRISING GIVEN THE COLD AIR BEHIND IT. THE RAP HAS A GOOD HANDLE ON THE FRONT/S SPEED AND IT WILL BE USED FOR TIMING. THE FRONT WILL ARRIVE INTO THE NORTHWEST CWA BY MID-MORNING AND CONTINUE TO TRACK SOUTHEAST...BUT SLOW DOWN A BIT DUE TO DAYTIME HEATING. THE FRONT SHOULD REACH A SHERMAN TO DFW TO COMANCHE LINE BY MID-AFTERNOON. THE AIRMASS AHEAD OF THE FRONT WILL BE WARM AND MOIST...WITH SEVERAL DAYS OF SOUTHERLY FLOW NOW BRINGING PRECIPITABLE WATER VALUES UP TO 1.75 TO 2 INCHES. SURFACE BASED CAPE WILL PEAK AROUND 2000-2500 J/KG THIS AFTERNOON AS TEMPS WARM INTO THE MID 80S. DAYTIME HEATING AND FORCING FOR ASCENT FROM THE UPPER LEVEL TROUGH WILL LIFT/ERODE THE WEAK CAPPING INVERSION...AND THUS CONVECTION WILL INCREASE IN COVERAGE ALONG THE FRONT BY LATE MORNING. BULK LAYER SHEAR IS FAIRLY WEAK...ON THE ORDER OF 25KT...SO MULTICELLULAR CONVECTIVE MODES ARE EXPECTED. GIVEN THE HIGH INSTABILITY AND WEAK SHEAR...SOME SEVERE WIND/HAIL REPORTS ARE POSSIBLE TODAY WITH THE STRONGEST STORMS. CONVECTION ALONG THE FRONT WILL LIKELY CONGEAL INTO A SOLID LINE OF THUNDERSTORMS BY MID-AFTERNOON...WITH THE LINE CONTINUING TO GROW UPSCALE INTO A FORMIDABLE LINEAR MCS BY THE EVENING HOURS. MCS PROPAGATION VECTORS AND DIFFLUENT THICKNESS FIELDS ALOFT SUGGEST THAT THE MOVEMENT OF THIS SYSTEM WILL REMAIN FAIRLY SLOW...LIKELY LESS THAN 10-15MPH. THIS FORWARD SPEED SHOULD IN THEORY LIMIT THE DAMAGING WIND THREAT THIS EVENING OVER THE SOUTHEAST HALF OF THE CWA...BUT WILL RESULT IN ENHANCED RAINFALL TOTALS. THE MCS WILL LIKELY HAVE SLOWER WEST TO EAST MOVEMENT THAN NORTH TO SOUTH...AND THUS THE ORIENTATION OF THE LINE SUGGESTS THAT EASTERN ZONES WILL HAVE A GREATER RISK FOR PROLONGED HEAVY RAINFALL. EXPECT THE LINE TO PUSH THROUGH THE SOUTHWEST ZONES FAIRLY QUICKLY...LIKELY REACHING A LAMPASAS TO WACO LINE BY 6 PM. A TIGHT RAINFALL GRADIENT IS FORECAST OVER THE CWA WITH LESS THAN A HALF INCH EXPECTED OVER THE NW ZONES...TO 1-2 INCHES IN A BAND FROM THE SHERMAN AREA TO THE METROPLEX TO COMANCHE...AND 2-3 INCHES SOUTH AND EAST OF A PARIS TO GREENVILLE TO HILLSBORO LINE. THIS LATTER REGION WAS THE SAME AREA THAT RECEIVED A SWATH OF 2-4 INCHES OF RAIN THURSDAY AND SOILS ARE ALREADY SATURATED. THUS A FLASH FLOOD WATCH WAS ISSUED FOR LOCATIONS ALONG AND SOUTHEAST OF A BONHAM TO DALLAS TO TEMPLE LINE. WHILE WE DONT EXPECT MOST OF DALLAS AND COLLIN COUNTIES TO RECEIVE MORE THAN 2 INCHES...GIVEN THE URBAN DEVELOPMENT THERE AND THE FACT THAT THE SOUTHEAST PARTS OF THESE COUNTIES DID SEE OVER 4 INCHES...FELT IT WAS BEST TO INCLUDE THEM. FARTHER SOUTH...FROM WACO TO ATHENS...LESS RAIN FELL IN THIS AREA LAST THURSDAY...BUT QUICK TOTALS OF 2-3 INCHES ARE POSSIBLE THIS EVENING. FOR WACO/TEMPLE/KILLEEN ONLY AROUND 2 INCHES ARE FORECAST...BUT AGAIN URBAN INFRASTRUCTURE MAY EXACERBATE ANY FLOODING...SO THEY WERE INCLUDED IN THE WATCH TOO. BECAUSE THE UPPER LEVEL TROUGH WILL BE SLOW TO MOVE EAST...CONTINUED SOUTHERLY FLOW ALOFT BEHIND THE FRONT/LINE OF STORMS WILL OCCUR THIS EVENING. THUS THE LINE OF STORMS WILL LIKELY BE SUCCEEDED BY A FEW HOURS OF STEADY LIGHT TO MODERATE STRATIFORM RAINS...ESPECIALLY ACROSS THE WATCH AREA. THIS ACTIVITY SHOULD END FROM NORTHWEST TO SOUTHEAST LATE TONIGHT...BUT MAY LINGER OVER THE SOUTHEAST ZONES INTO TUESDAY MORNING. TUESDAY SHOULD BE DRY FOR THE REMAINDER OF THE AREA WITH MOSTLY CLOUDY AND COOL CONDITIONS AS COOLER AIR POURS INTO THE REGION BEHIND THE FRONT. FORECAST HIGH TEMPS MAY BE TOO WARM...BUT IT WOULD ONLY TAKE AN HOUR OR TWO OF AFTERNOON MAY SUNSHINE TO WARM US INTO THE MID 60S...SO STAYED CONSERVATIVE THERE. THE STRONGEST UPPER LEVEL FORCING WILL CROSS THE REGION TUESDAY EVENING BUT THE AIRMASS WILL BE PRETTY WORKED OVER. HOWEVER THIS FORCING SHOULD RESULT IN SCATTERED ELEVATED SHOWERS AND A FEW STORMS OVER THE REGION AND SHOULD SQUEEZE OUT ANOTHER TENTH TO QUARTER INCH OF RAINFALL. HAVE BUMPED POPS UP TUESDAY NIGHT AS MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT ON THIS ROUND. OTHERWISE THE REMAINDER OF THE FORECAST LOOKS QUIET AND VERY NICE FOR MID TO LATE MAY. DRY NORTHWESTERLY FLOW ALOFT WILL PREVAIL THROUGH THE WEEKEND LEADING TO CLEAR SKIES AND LIGHT WINDS. GOOD RADIATIONAL COOLING WEDNESDAY NIGHT WILL SEND LOW TEMPS DOWN INTO THE 40S AREA WIDE...AND WACO MAY BREAK ITS RECORD LOW OF 46. HIGHS IN THE UPPER 60S ARE EXPECTED THURSDAY...BUT TEMPS SHOULD WARM INTO THE 70S FRIDAY AND THE 80S BY THE WEEKEND. DRY WEATHER WILL CONTINUE INTO NEXT WEEK WITH TEMPS WARMING TO ABOVE NORMAL. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 83 54 66 51 68 / 90 80 20 40 10 WACO, TX 87 57 65 51 69 / 70 100 40 60 10 PARIS, TX 84 56 63 51 64 / 70 90 20 50 20 DENTON, TX 80 52 65 49 68 / 80 70 20 40 10 MCKINNEY, TX 83 53 64 50 68 / 90 80 20 40 10 DALLAS, TX 84 55 65 52 68 / 90 80 20 50 10 TERRELL, TX 85 57 64 51 67 / 70 90 20 50 20 CORSICANA, TX 86 59 64 52 67 / 60 100 40 60 20 TEMPLE, TX 87 58 64 52 69 / 50 100 50 60 10 MINERAL WELLS, TX 79 50 66 47 71 / 70 60 20 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM THIS AFTERNOON THROUGH LATE TONIGHT FOR TXZ094-095-104>107-119>123-134-135-145>148-158>162-174-175. && $$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1248 AM CDT MON MAY 12 2014 .DISCUSSION...NOTE AVIATION DISCUSSION BELOW. && .AVIATION...MVFR/IFR CEILINGS EXPECTED OVERNIGHT. MVFR/VFR CEILINGS EXPECTED DRG THE DAYTIME MONDAY ALONG WITH THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS...WITH MVFR VISIBILITIES... DRG THE AFTN MAINLY WEST OF U.S. ROUTE 77. THE CHANCE FOR SHOWERS AND THUNDERSTORMS WL INCREASE MONDAY EVENING/NIGHT. ANTICIPATE THAT VERTICAL WIND SHEAR WL REMAIN BELOW NON-CONVECTIVE LLWS CRITERION OVERNIGHT. MODERATE/BREEZY ONSHORE FLOW EXPECTED DRG THE LATE MORNING/AFTN. && .PREV DISCUSSION... /ISSUED 917 PM CDT SUN MAY 11 2014/ DISCUSSION...MINOR TEMPERATURE/DEW POINT ADJUSTMENTS TO FALL IN LINE WITH CURRENT/FORECAST TEMPERATURES. SEE NO REASON AT THIS TIME TO MAKE OTHER CHANGES INLAND AREAS. MARINE...INCLUDED PATCHY FOG FOR THE MARINE ZONES AND SOME LOCATIONS REPORTING 2-5SM. WILL PUT A BRIEF MENTION OF THIS IN MWW. AM KEEPING SCA GOING AS THIS IS WHAT THE RUC IS SHOWING AND OTHER MODELS TOO. PREV DISCUSSION... /ISSUED 644 PM CDT SUN MAY 11 2014/ DISCUSSION...UPDATE FOR 00Z AVIATION DISCUSSION. AVIATION...DETERIORATING FLIGHT RULES OVERNIGHT. MVFR EARLY IN THE TAF PERIOD AT KCRP/KVCT/KALI WITH CONDITIONS QUICKLY LOWERING TO IFR BY MID EVENING...AND REMAINING AT IFR OVERNIGHT. KLRD SHOULD REMAIN VFR THRU MUCH OF THE NIGHT WITH CIGS LOWERING TO IFR BY LATE IN THE NIGHT. CIGS AT ALL TERMINALS WILL SLOWLY RISE MON MRNG WITH MVFR TO VFR RETURNING TO KLRD BY LATE MRNG...KALI BY MIDDAY...WITH KCRP/KVCT LIKELY REMAINING AT MVFR THRU MON AFTN. ISO CONVECTION MAY APPROACH KLRD BY LATE MON AFTN BUT BETTER CHANCES WILL OCCUR JUST BEYOND VALID TAF TIME FRAME...SO WILL ONLY INCLUDE VCTS FOR NOW. ELSEWHERE...CURRENTLY XPCT KCRP/KVCT/KALI TO REMAIN DRY THRU THE TAF PERIOD ASIDE FROM SOME BRIEF -DZ. MODERATE/GUSTY SE WINDS THIS EVENING WILL REMAIN BETWEEN 08-14 KTS OVERNIGHT...WITH GUSTY SE WINDS RETURNING FOR MIDDAY/AFTN HRS OF MON. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 88 73 76 59 75 / 30 50 70 60 20 VICTORIA 88 72 75 57 75 / 30 60 70 60 20 LAREDO 96 74 80 61 79 / 40 70 60 40 10 ALICE 91 72 77 58 76 / 30 60 70 60 20 ROCKPORT 84 73 75 62 74 / 20 40 70 60 20 COTULLA 92 71 77 57 78 / 40 70 50 40 10 KINGSVILLE 90 73 77 59 76 / 30 50 70 60 20 NAVY CORPUS 84 73 75 61 74 / 20 40 60 60 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. && $$ WC/87...AVIATION
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1157 PM CDT SUN MAY 11 2014 .AVIATION... /06Z TAFS/ Thunderstorms and widespread MVFR ceilings do not look likely for the remainder of tonight. The latest satellite imagery indicates stratus is returning. However, the latest METAR for Junction indicates a broken ceiling at only twenty nine hundred feet above ground level. So, stratus may not be as low as the previous forecast package indicated. Thunderstorms, associated with the cold front, still look possible for tomorrow. && .PREV DISCUSSION... /ISSUED 813 PM CDT SUN MAY 11 2014/ DISCUSSION... Despite the instability in place and persistent cumulus field, thunderstorms have not developed along the dryline so far this evening in the eastern TX Panhandle or Low Rolling Plains east of Lubbock. Surface convergence is weak and upper forcing is still lagging to the west over the southern Rockies. The dryline farther south is retreating to the west. The GFS looks to be the the most optimistic with convective development early tonight before 06Z in our northern and western counties. Recent HRRR and Texas Tech WRF, however, hold off with shower/thunderstorm development until 2-3 hours after Midnight across our far western counties. The Texas Tech WRF indicates possibility of isolated thunderstorm development near our northwestern border counties (Fisher and Nolan Counties) late this evening/early tonight. Given the satellite and model trends, have scaled back the PoPs early tonight with slight chance confined to the the area west of Haskell to Sweetwater before 2 AM. With the instability and deep layer shear, severe potential remains for any storms which can develop on the dryline. As large scale ascent begins to impinge on the area late tonight, could have shower/thunderstorm development across our west and northwest counties, spreading east overnight and early Monday morning. Carrying 30-40 PoPs across the area north and west of a San Angelo to Baird line late tonight. Have also adjusted sky condition to clear skies this evening based on satellite indications. Updated forecast will be out shortly. 19 PREV DISCUSSION... /ISSUED 650 PM CDT SUN MAY 11 2014/ AVIATION... /00Z TAFS/ Thunderstorms and MVFR ceilings are possible across West Central Texas during the next 24 hours. Forecast models indicate stratus will return to our southern terminals a couple hours after midnight. The best timing for thunderstorms will also begin after midnight and continue through tomorrow, as another cold front moves into West Central Texas. PREV DISCUSSION... /ISSUED 335 PM CDT SUN MAY 11 2014/ SHORT TERM... (Tonight and Monday) A fairly complex weather forecast can be expected through the next 24 hours. Currently a dryline is located west of the area, with all of West Central Texas experiencing dewpoints in the mid 50s to lower 60s. The dryline is forecast to continue to sharpen to our west this afternoon, with an increasingly unstable atmosphere ahead of it. The main caveat is the lack of upper level forcing, and whether we are able to break the cap late this afternoon or early this evening. My current thinking is that we will see at least isolated convection along the dryline, mainly beginning this evening as better upper level forcing arrives, then moving east late this evening and early Monday morning. A strengthening low level jet should help to sustain any convection that does develop, with most convection waning by sunrise. Any storms that do develop this evening, have the potential to become strong to severe, with large hail and damaging winds being the main hazards. The main feature of interest on Monday is a cold front that will slowly move through the area. The front is forecast to move into the northern Big Country late Monday morning, then into the Concho Valley during the afternoon, with a dryline extending south across the northern Edwards Plateau. Showers and thunderstorms are forecast to develop along and ahead of the front late in the morning, then increase in coverage by mid to late afternoon. At this time, the best coverage and heaviest rainfall looks to generally east of a Cross Plains, to Eden, to Junction line, where precipitable water values of 1 to 1.5 inches are forecast. Again, a few storms could become strong to severe, with large hail and damaging winds being the main hazards. Daniels LONG TERM... (Monday night through Sunday) ..A heavy rainfall threat will exist through Monday night... A very slow moving cold front will ease across the southeast quadrant of the CWA Monday night, providing a low-level focus for convective development. Ascent will be aided by strong upper-level divergence in the right entrance region to the polar jet. Forecast precipitable water values Monday night are progged to be in the 1.4 to 1.7" range, about 2 standard deviations above the mean for this time of year. The 0-6km shear vector will be nearly parallel with the aforementioned frontal boundary, suggesting that storms may train along the baroclinic zone, enhancing the potential for locally heavy rainfall. Widespread showers and thunderstorms will result in general rainfall amounts of 1-3", with locally higher amounts, generally east of a Cross Plains to Junction line. Farther west, QPF amounts are quite a bit lighter, but a good 1/4" of rain or more is expected from Sweetwater south to Sonora. There is a threat for severe thunderstorms as well, mainly during the afternoon and evening hours before convection congeals into a multicell mess. The primary threats will be large hail and damaging winds. The cold front will be south of the area by Tuesday morning with north winds of 15-20 mph expected throughout the day. Upper-level forcing will remain present, but without the frontal forcing, it looks like precipitation will be weaker, with thunder becoming less likely. PoPs in the 20-40% range were carried southeast of an Ozona to Cross Plains line, but rainfall amounts should remain less than 1/4" on average. Temperatures will be noticeably cooler on Tuesday with highs generally in the mid 60s. The NAM is still keeping highs in the 50s across the area but this seems a bit extreme. Precip is expected to come to an end by Tuesday evening with drier air advecting into the area overnight. As winds decrease, the dry air should allow fairly strong decoupling of the boundary layer. With skies clearing, temps are expected to fall into the low/mid 40s. North to northeast winds on Wednesday will keep temps on the cool side, with highs only the 70s. We`re in store for another cool morning on Thursday with 40s once again expected across most of the area. Generally benign weather conditions are expected through the remainder of the forecast period. Dry northwesterly flow downstream of the western CONUS ridge will promote mostly clear skies. Southerly winds will resume across the area by Thursday as lee cyclogenesis ramps up. With the return flow, temps will rebound quickly into the 80s with highs expected to reach 90 degrees over the weekend. This is a potential cold front we`ll have to watch out for Friday into Saturday as a potent shortwave trough moves across the central Plains. However, the current model guidance stalls this boundary near the Red River, maintaining southerly winds across the region. Johnson FIRE WEATHER... Elevated fire weather conditions are forecast across the western Concho Valley and Crockett County Monday afternoon. Minimum relative humidity values will drop below 20 percent, but 20 foot winds will remain light. Elevated fire weather conditions will once again be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 69 80 50 66 46 / 30 40 20 10 5 San Angelo 69 84 52 65 44 / 30 30 30 10 5 Junction 72 82 57 68 47 / 10 50 70 40 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
501 AM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST IS GOING TO KEEP OUR REGION IN A INCREASINGLY HUMID AIRMASS. A SLOW MOVING FRONT ENTERS THE REGION BY THURSDAY AND SLIDES EAST FRIDAY. A COOLER AIRMASS FOLLOWS THIS FRONT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 400 AM EDT MONDAY... DESPITE INCREASING 5H HEIGHTS TODAY...WILL STILL SEE A COUPLE OF EMBEDDED SHORTWAVES RIDE THE NRN CENTER OF THE HIGH ACROSS OUR AREA. EARLY THIS MORNING...THERE IS A WEAK SHORTWAVE MOVING ACROSS WV WITH TAIL END OF SHOWERS PUSHING EAST BETWEEN BKW-CRW BUT WEAKENING. THE LATEST HRRR SHOWS THIS AREA MAYBE SCRAPING NRN GREENBRIER AND BATH. OVERALL...SHOULD BE A DRY MORNING WITH PATCH FOG IN THE VALLEYS/RIVER AREAS. TODAY...THE SFC HIGH OFF THE COAST WILL CONTINUE TO KEEP MOISTURE STREAMING NWD INTO THE CENTRAL APPALACHIANS. HEATING WILL LEAD TO INSTABILITY AND OVERALL WEAK FORCING FAVORS SCATTERED SHOWERS AND STORMS POPPING AROUND MIDDAY IN THE MTNS WITH STEERING FLOW TAKING THEM EAST TO THE BLUE RIDGE AND FOOTHILLS DURING THE AFTERNOON. FURTHER SOUTH ACROSS NC/SOUTHSIDE VA...AIRMASS MAY BE JUST CAPPED ENOUGH TO LIMIT CONVECTION...ALTHOUGH A FEW SHOULD SKIRT BY THIS EVENING WHEN CAP WEAKENS. OVERALL KEPT POPS UNDER HIGH CHANCE...BUT WILL BE A CASE WHERE 1/3-1/2 OF A COUNTY GETS RAINED ON...WHILE THE OTHER HALF MISSES OUT. FOR HIGHS WILL SEE MOSTLY SUNNY SKIES EARLY WITH CU/TCU DEVELOPING WITH SOME AC/CI OVERTOP. THIS WILL LIMIT HEATING MAINLY OVER THE MOUNTAINS BUT STILL LOOKING AT TEMPS RUNNING AROUND 10 DEGREES ABOVE NORMAL. HIGHS RANGING FROM THE UPPER 70S/LOWER 80S WEST TO NEAR 90 SOUTHEAST. TONIGHT...CONVECTION WEAKENS WITH LOSS OF HEATING. THE 00Z WRF/NAM HOLD ONTO ACTIVITY INTO LATE EVENING WHILE THE OTHER MODELS SHOWING LITTLE TO NONE AFTER 00Z/8 PM. WILL LEAN TOWARD THE HIGHER RES MODELS SINCE ANY OUTFLOW COULD KEEP A SHOWER/STORM GOING PAST 8 PM. BY MIDNIGHT WILL BE CLEAR TO PARTLY CLOUDY AND HUMID WITH LOWS IN THE UPPER 50S TO LOWER 60S. FOG COULD BECOME AN ISSUE SINCE RAIN SHOWERS ARE EXPECTED THIS AFTERNOON...ALTHOUGH COVERAGE WILL BE PATCHY. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 415 AM EDT MONDAY... UPPER LEVEL RIDGING WILL BE FIRMLY IN PLACE TUESDAY MORNING ACROSS THE EASTERN SEABOARD...WHICH WILL RESULT IN VERY SUMMER LIKE TEMPERATURES. EXPECT AFTERNOON HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS... TO THE LOW 90S ACROSS THE SOUTHSIDE. STRONG HEATING AND CONTINUED MOISTURE INFLOW SHOULD HELP KICK OFF A FEW SHOWERS AND THUNDERSTORMS DURING LATE AFTERNOON AND EARLY EVENING... HOWEVER THE RIDGING WILL KEEP THIS ACTIVITY SPOTTY AT BEST AND DISORGANIZED. WILL BE KEEPING AN EYE ON A COLD FRONT BACK DOORING ITS WAY SOUTHWARD FROM NEW ENGLAND DURING THE AFTERNOON AND EVENING...BUT DO NOT THINK IT WILL APPROACH CLOSE ENOUGH TO ENHANCE CONVECTION OVER OUR AREA. AT ANY RATE...ANY CONVECTION SHOULD GRADUALLY FIZZLE TOWARD SUNSET...AND PATCHY FOG WILL BE POSSIBLE TUESDAY NIGHT...ESPECIALLY IN AREAS WHICH DO RECEIVE A DOWNPOUR. BETTER CHANCES FOR SHOWER AND THUNDERSTORMS WILL OCCUR ON WEDNESDAY AS UPPER LEVEL RIDGING BEGINS TO SHIFT EAST...WHILE THE BACK DOOR FRONT STALLS ACROSS NORTHERN VIRGINIA JUST OUTSIDE OUR FORECAST REGION. ANOTHER DAY OF STRONG HEATING AS HIGHS REACH INTO THE 80S MOST LOCATIONS...COMBINED WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE NEARBY FRONT...WILL LEAD TO HIGHER RAIN CHANCES ACROSS THE MOUNTAINS AND THE PIEDMONT NORTH OF HIGHWAY 460. THE INCREASED INSTABILITY WILL ALLOW FOR GREATER POTENTIAL FOR ORGANIZED THUNDERSTORM ACTIVITY...AND A FEW STORMS WILL LIKELY BECOME STRONG DURING LATE AFTERNOON AND EARLY EVENING...CAPABLE OF PRODUCING LOCALLY STRONG WINDS AND HAIL. WILL SEE THE BOUNDARY ACROSS NORTHERN VIRGINIA LIFT TOWARD NEW ENGLAND DURING LATE EVENING AS A WARM FRONT...WHILE A STRONG COLD FRONT APPROACHES OUR REGION FROM THE WEST. THE COLD FRONT WILL ENTER OUR WESTERN MOST COUNTIES DURING MID AFTERNOON...RESULTING IN WAVES OF LOCALLY HEAVY RAIN AS UPPER LEVEL DISTURBANCES PASS OVERHEAD ALONG THE BOUNDARY. MODELS ARE PICKING UP ON AT LEAST ONE STRONG WAVE POTENTIALLY BRINGING HEAVY RAIN TO THE FOOTHILLS AND THE PIEDMONT DURING THE EVENING...AND POSSIBLY A SECOND WAVE IF THE COLD FRONT SLOWS/STALLS BEFORE EXITING OUR REGION DURING EARLY FRIDAY MORNING. STILL NOT ENOUGH CONFIDENCE IN THE MODELS TO TACK DOWN RAINFALL AMOUNTS...BUT IT IS LOOKING SAFE TO SAY THAT THE MUCH OF THE REGION WILL RECEIVE BETWEEN ONE AND TWO INCHES FOR THE THURSDAY AND EARLY FRIDAY TIME PERIOD...WITH SOME AREAS PICKING IN EXCESS OF 3 INCHES...ESPECIALLY ALONG THE BLUE RIDGE. MODELS ARE IN DECENT AGREEMENT THAT THE FRONT AND ASSOCIATED HEAVY RAIN WILL BE EAST OF OUR AREA DURING EARLY FRIDAY AFTERNOON... LEAVING ONLY RESIDUAL SHOWER ACTIVITY...AS WELL AS A SHARP DROP IN TEMPERATURES AS A DEEP UPPER TROUGH APPROACHES FROM THE WEST. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 400 PM EDT SUNDAY... AN AMPLIFIED MID-UPPER LEVEL MEAN TROUGH SETTLES OVER THE ERN HALF OF THE CONUS FOR THE LATTER HALF OF THE WEEK AND INTO NEXT WEEKEND. AS WE TRANSITION INTO THE WEEKEND...FLOW BECOMES BLOCKY WITH A DEEP QUASI-STATIONARY...ALMOST WINTERLIKE UPPER LOW PARKED OVER THE GREAT LAKES REGION. 850MB TEMPS WILL DROP INTO THE 3C TO 6C RANGE FOR MOST OF THE CWA AND LINGER IN THIS RANGE FOR SEVERAL DAYS. SEVERAL SPOKES OF PVA ARE EXPECTED TO ROTATE AROUND THIS UPPER LOW WHICH SUGGESTS POTENTIAL FOR CLOUDS AND SHOWERS... ESPECIALLY ACROSS THE MOUNTAINS. TEMPERATURES WILL TREND TO THE COOLER SIDE OF NORMAL. FORTUNATELY...CLOUDS...SHOWERS...AND A BIT OF A NW BREEZE SHOULD MITIGATE FROST POTENTIAL. NONETHELESS...IT WILL BE QUITE CHILLY WITH HIGHS IN THE 60S AND LOWS IN THE 40S ACROSS MUCH OF THE REGION...A BIG CONTRAST FROM THE WARMTH THE FIRST HALF OF THIS WEEK. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... AS OF 120 AM EDT MONDAY... CIRRUS FROM UPSTREAM CONVECTION ALONG WITH SCATTERED AC WILL BE PUSHING ACROSS SE WV THIS MORNING AND PORTIONS OF THE ROA/BCB CORRIDOR. OVERALL THE CONDITIONS WILL BE VFR...WITH MOISTURE SITUATED IN THE SFC LAYER TO PROVIDE FOG POTENTIAL AT ALL SITES WITH BEST THREAT AT BCB/LWB...TO GO AS LOW AS LIFR AROUND 09-12Z. THE HIGH CLOUDINESS IF IT HANGS AROUND WILL PRECLUDE THIS BUT CONFIDENCE IS ENOUGH THINNING AND CALM WINDS TO ADD IT TO THE TAFS. TODAY...ANY FOG BURNS OFF AROUND 12-13Z. SW FLOW ALOFT PLUS HEATING THROUGH THE DAY WILL BE ENOUGH TO PRODUCE SCT/BKN CU...WITH HIGHER COVERAGE OVER THE MOUNTAINS. PER LATEST NAM/WRF...SHOULD SEE ISOLATED COVERAGE OF SHOWERS/STORMS IN THE PIEDMONT THIS AFTERNOON WITH SCATTERED COVERAGE ALONG AND WEST OF THE BLUE RIDGE. THINK HIGH PRESSURE ALOFT MAY CAP THINGS ACROSS SOUTHSIDE VA/DAN AND POINTS SOUTH. FOR NOW HAVE VCTS AT ALL BUT DAN DURING THE AFTERNOON...BEFORE TAKING IT OUT AROUND 0Z TUE. UPPER RIDGE ALOFT STRENGTHENS OVER THE REGION TUESDAY...PROVIDING MAINLY VFR CONDITIONS. THE UPPER RIDGE WILL SHIFT EAST OF THE REGION WEDNESDAY AS A STRONG COLD FRONT AND DEEPENING UPPER LOW MOVE INTO THE AREA FROM THE CENTRAL UNITED STATES. THIS SYSTEM HAS THE POTENTIAL TO BRING AN EXTENDED PERIOD OF SHRA/TSRA AND ASSOCIATED MVFR OR LOWER CIGS AND VSBYS TO THE REGION...LINGERING PERHAPS INTO EARLY FRIDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PC/WP NEAR TERM...WP SHORT TERM...NF LONG TERM...PM AVIATION...RCS/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1133 PM CDT SUN MAY 11 2014 .UPDATE... ISSUED AT 938 PM CDT SUN MAY 11 2014 WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR POSSIBLE OVERNIGHT AND GRB ADDING A FLASH FLOOD WATCH FOR SOME OF THEIR COUNTIES IN NORTH CENTRAL WISCONSIN...HAVE DECIDED TO CHANGE OVER THE FLOOD WATCH TO A FLASH FLOOD WATCH AND EXTEND IT THROUGH 6Z TUESDAY WHEN THE COLD FRONT SHOULD BE CLEAR OF THE REGION. TIMING OF THE COMPLEX MAKING IT INTO NORTHEAST IOWA STILL LOOKS GOOD FOR AROUND MIDNIGHT NEAR THE I-35 CORRIDOR...IT IS JUST A MATTER OF HOW INTENSE IT WILL BE AS IT GETS IN. UPDATE ISSUED AT 855 PM CDT SUN MAY 11 2014 THE MAIN FOCUS WITH THE FORECAST IS WITH THE SEVERE WEATHER POTENTIAL OVERNIGHT. CURRENT SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM CENTERED NEAR OMAHA WHERE A BOWING COMPLEX HAS EMERGED FROM A LONG TRACK HP SUPERCELL THAT TRACKED ACROSS SOUTHEAST NEBRASKA THIS AFTERNOON. THE MAIN SURFACE WARM FRONT APPEARS TO EXTEND EAST FROM OMAHA ACROSS SOUTHERN IOWA WITH AN INVERTED TROUGH EXTENDING NORTH FROM THE LOW INTO SOUTHWEST MINNESOTA. ANOTHER DEW POINT GRADIENT EXISTS ALONG THE MINNESOTA/IOWA BORDER WHERE DEW POINTS GO FROM THE MID 50S IN SOUTHEAST MINNESOTA TO THE LOW 60S IN NORTHEAST IOWA. 12.00Z RAP ANALYSIS SUGGESTS THAT THERE STILL IS QUITE A BIT OF INSTABILITY AHEAD OF THIS COMPLEX RUNNING EAST ACROSS IOWA WITH 0-3KM MUCAPE AROUND 2000 J/KG FROM DES MOINES EAST AND AROUND 1000 J/KG RUNNING ALONG THE MINNESOTA/IOWA BORDER. SURFACE BASED CAPE IS STARTING TO DECREASE...BUT IS STILL FAIRLY DECENT OUT AHEAD OF THE BOW AT 2000 J/KG. SHORT TERM GUIDANCE HAS BEEN VERY CONSISTENT THIS AFTERNOON/EARLY EVENING WITH SHOWING AN INITIAL BAND OF MAINLY WEAK CONVECTION DEVELOPING ALONG THE LEADING EDGE OF THE 925-850MB MOISTURE TRANSPORT AND LIFTING NORTH THROUGH THE EVENING. THE MAIN QUESTION IS WITH WHERE THE COMPLEX IN WESTERN IOWA WILL TRACK. WITH THE 925MB JET AND MOISTURE TRANSPORT INCREASING AND LIFTING NORTH OVERNIGHT...THE SUPPORT IS THERE FOR ANY CONVECTION TO CONTINUE TO TRACK EAST-NORTHEAST. FORWARD PROPAGATING CORFIDI VECTORS AND 0-3KM SHEAR IS ALL POINTING FROM THE SOUTHWEST TO THE NORTHEAST AND THAT HAS BEEN BACKED BY THE INITIAL TRENDS WITH THE BOW. CURRENT EXTRAPOLATION AND MESO-MODELS WOULD SAY THAT THE LEADING EDGE OF THIS COMPLEX WOULD BE INTO THE CHARLES CITY IOWA AREA AROUND OR SHORTLY AFTER MIDNIGHT...TO THE MISSISSIPPI RIVER IN NE IA/SW WI AROUND 3AM...AND ON INTO SOUTH CENTRAL WISCONSIN BY 5AM. THIS LINE OF STORMS HAS ALREADY PRODUCED 80MPH WIND GUSTS AT OMAHA...BUT DO NOT EXPECT IT TO BE AT THAT STRENGTH...BUT STILL POSSIBLY SEVERE...AS IT GETS INTO THE REGION. AM CONSIDERING CHANGING THE FLOOD WATCH TO A FLASH FLOOD WATCH SINCE THERE APPEARS TO BE A CHANCE THAT THIS COMPLEX SLOWS DOWN AND PRODUCES SOME HEAVY RAINFALL OVER A SHORT PERIOD OVERNIGHT THAT IS TIED MORE TO CONVECTION THAN A LONG LIVED MODERATE RAIN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 325 PM CDT SUN MAY 11 2014 FOCUS OF THE FORECAST IS ON RAIN THROUGH TUESDAY. REGIONAL RADARS SHOW A CONVECTIVE COMPLEX HAS SURVIVED FROM THE OVERNIGHT HOURS AND CONTINUES TO TRANSLATE ACROSS SOUTHERN IOWA. THAT HAS EFFECTIVELY PINNED THE WARM FRONT WELL SOUTH OF THE AREA ALONG THE IOWA/MISSOURI BORDER. THIS HAS ALSO PINNED MOST OF THE CAPE TO THE SOUTH WITH THE 19Z MU CAPE SHOWING LESS THAN 500 J/KG ACROSS THE AREA. THE CONCERN BECOMES WHAT HAPPENS THIS EVENING AS THE COMPLEX CONTINUES TO MOVE EAST AND IF THE WARM FRONT CAN MAKE A MOVE NORTH. THE 11.17Z HRRR SUGGESTS THAT THE WARM FRONT WILL START TO PUSH NORTH THIS EVENING BUT MAY STILL BE ONLY ABOUT AS FAR NORTH AS THE INTERSTATE 80 CORRIDOR BY 03Z. THE WARM FRONT COULD THEN GET PUSHED NORTHEAST THROUGH THE REST OF THE EVENING AND NIGHT AS A STRONG SHORT WAVE TROUGH MOVES NORTHEAST ACROSS THE REGION. THE 11.12Z NAM DOES SUGGEST BETWEEN 1000-1500 J/KG OF ML CAPE WILL BE IN PLACE ALONG AND NEAR THE WARM FRONT...BUT IF THE WARM FRONT GETS PUSHED NORTHEAST...THIS CAPE MAY JUST CLIP THE SOUTHEAST PORTIONS OF THE AREA. HOWEVER...IF THIS SCENARIO DOES NOT PLAY OUT AND THE CAPE IS FARTHER WEST...THERE WILL STILL BE A SEVERE THREAT. THE 0-6KM SHEAR THIS EVENING SHOULD INCREASE TO A RANGE OF 30 TO 50 KNOTS THIS EVENING THEN TO AROUND 60 KNOTS FOR THE OVERNIGHT HOURS. THE NAM REMAINS CONSISTENT SHOWING 200-300 M2/S2 OF HELICITY OVER THE AREA IN THE 0-3KM LAYER WITH THE BULK OF THE RESIDING THE 0-1KM LAYER. SO IF THE WARM FRONT CAN GET INTO THE AREA...THERE WOULD STILL BE A THREAT FOR AN ISOLATED TORNADO...BUT CONFIDENCE ON THE POSITION OF THE WARM FRONT IS NOT VERY HIGH. CONFIDENCE IS HIGH THAT IT WILL RAIN TONIGHT. THE MODELS HAVE BEEN CONVERGING TOWARD THE SCENARIO THAT AS THE SHORT WAVE TROUGH COMES OUT OF THE CENTRAL PLAINS AND MOVES NORTHEAST OVER THE REGION TONIGHT THAT CONVECTION WILL FORM ALONG AN INVERTED TROUGH. THIS TROUGH CURRENTLY EXTENDS FROM THE SOUTHWEST KANSAS ACROSS WESTERN IOWA INTO WESTERN WISCONSIN. AS THE SHORT WAVE TROUGH COMES OUT...MODERATE PV ADVECTION IN THE 500-300 MB LAYER IS EXPECTED TO OCCUR. IN THE LOW LEVELS...THE WARM AIR ADVECTION WILL INCREASE AHEAD OF THE WAVE WITH 5 TO 7 UBAR/S OF UP GLIDE ON THE 300K ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS LEVEL RIGHT INTO THE AREA. EXPECT TO SEE THE LINE OF CONVECTION DEVELOP IN RESPONSE TO THIS WAVE FROM SOUTHERN MINNESOTA INTO KANSAS AND THEN MOVE NORTHEAST ACROSS THE AREA THROUGH THE NIGHT. ONCE THE SHORT WAVE TROUGH MOVES PAST...THE FORCING WILL SHIFT BACK TO THE WEST AGAIN AHEAD OF THE MAIN LONG WAVE TROUGH AND THE EMBEDDED SHORT WAVE TROUGH. THIS IS EXPECTED TO MAKE THE MAIN SURFACE LOW MOVE FROM KANSAS INTO MINNESOTA OR WISCONSIN DURING THE DAY MONDAY WITH THE COLD FRONT ADVANCING EAST INTO THE AREA. ANOTHER ROUND OF VERY SIMILAR ISENTROPIC UP GLIDE AND MOISTURE TRANSPORT IS EXPECTED ON THE 300K SURFACE FOR CONTINUED SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT. EVERYTHING THEN STARTS TO TRANSLATE EAST FOR MONDAY NIGHT WITH THE RAIN CHANCES ENDING FROM WEST TO EAST THROUGH TUESDAY MORNING. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 325 PM CDT SUN MAY 11 2014 WILL CARRY SOME SMALL RAIN CHANCES FOR WEDNESDAY THROUGH FRIDAY AND THEN SOME ON AND OFF CHANCES OVER THE WEEKEND. ONCE THE SYSTEM FROM EARLY IN THE WEEK MOVES PAST...THE LONG WAVE TROUGH LOOKS TO REMAIN OVER THE CENTRAL PART OF THE COUNTRY WITH A NORTHWEST FLOW FROM NORTHWEST CANADA. THIS SHOULD ALLOW SEVERAL WEAK SHORT WAVE TROUGHS TO ROTATE THROUGH THE LONG WAVE TROUGH TO SUPPORT THE RAIN CHANCES. THIS FLOW WILL ALSO HELP TO KEEP TEMPERATURES BELOW NORMAL WITH HIGHS IN THE 50S TO END THE WEEK AND THEN CREEPING BACK INTO THE 60S FOR THE WEEKEND. OVERNIGHT LOWS WILL BE IN THE 30S AND MAY HAVE TO DEAL WITH SOME FROST HEADLINES TOWARD THE END OF THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1133 PM CDT SUN MAY 11 2014 A BAND OF SHOWERS AND THUNDERSTORMS ARE CURRENTLY MOVING ACROSS SOUTHEAST MINNESOTA AND NORTH CENTRAL IOWA AND WILL CONTINUE TO TRACK TO THE EAST THROUGH THE EARLY MORNING HOURS. VISIBILITY HAS DROPPED TO 1SM WITH SOME OF THE STRONGER THUNDERSTORMS...SO HAVE KEPT THAT AS THE TEMPO GROUP THROUGH 10Z AT LSE AND 8Z AT RST. IT APPEARS THAT THIS RAIN WILL TRACK EAST WITH A DRY PERIOD POSSIBLE THROUGH THE REST OF THE MORNING. ANOTHER ROUND OF CONVECTION WILL DEVELOP IN THE AFTERNOON...BUT CONFIDENCE IS NOT VERY HIGH AT THIS POINT WITH HOW IT WILL PAN OUT AND WHEN IT WILL COME THROUGH THE TAF SITES. && .HYDROLOGY... ISSUED AT 325 PM CDT SUN MAY 11 2014 RAINFALL FROM THIS SYSTEM THROUGH MONDAY SHOULD AVERAGE AROUND 2 INCHES FOR MUCH OF THE FORECAST AREA WITH LOCALIZED HIGHER AMOUNTS EXPECTED. MANY OF THE RIVERS REMAIN HIGH FROM RECENT RUN OFFS AND THE LATEST FORECASTS FROM THE RFC INDICATED WITHIN BANK RISES FOR MANY OF THE TRIBUTARIES WITH RENEWED FLOODING POSSIBLE AT SOME SPOTS ALONG THE MISSISSIPPI. IF THE RAINFALL ENDS UP BEING HIGHER THAN THE QPF USED BY THE RFC...WHICH IS HIGH PROBABILITY...SOME THE TRIBUTARIES COULD ALSO GO TO FLOOD. BASED ON THIS...HAVE OPTED TO ISSUE A FLOOD WATCH FOR THE ENTIRE AREA FOR TONIGHT AND MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR WIZ017-029- 032>034-041>044-053>055-061. MN...FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR IAZ008>011-018- 019-029-030. && $$ UPDATE...HALBACH SHORT TERM...04 LONG TERM...04 AVIATION...HALBACH HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1014 AM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE REMAINS IN CONTROL THROUGH TODAY THEN A BACK DOOR COLD FRONT STARTS MOVING THROUGH THE REGION LATE TONIGHT INTO TUESDAY. MARITIME HIGH PRESSURE WEDNESDAY PROVIDES BELOW AVERAGE TEMPERATURES FOLLOWED BY A PERIOD OF UNSETTLED WEATHER THURSDAY THROUGH SATURDAY. BEST CHANCE OF HEAVY RAIN AND POSSIBLE THUNDERSTORMS EXPECTED FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 10 AM UPDATE... ANOTHER SPECTACULAR DAY IN PROGRESS WITH DEEP LAYER RIDGE OVER THE EASTERN GREAT LAKES AND SURFACE HIGH SOUTH OF NEW ENGLAND. THIS SETUP IS PROVIDING LARGE SCALE SUBSIDENCE OVER THE REGION ALONG WITH LOW LEVEL WESTERLY FLOW. THUS ABUNDANT SUNSHINE PREVAILS ALONG WITH COMFORTABLE HUMIDITY WITH DEW PTS IN THE 30S AND 40S. UPSTREAM SOUNDING AT ALBANY NY SUPPORTS HIGHS AROUND 80F WITH 850 TEMPS OF +11C. HOWEVER WITH BLYR EXTENDING UP TO 700 MB ALONG WITH WESTERLY BLYR WINDS HIGHS WILL CLIMB INTO THE M80S WITH A LOW PROBABILITY OF A FEW SPOTS BRIEFLY GETTING INTO THE U80S! THUS HAVE INCREASED HIGHS A TAD FROM PREVIOUS FORECAST. THINK DRY WEATHER WILL PREVAIL TODAY DESPITE BACKDOOR FRONT APPROACHING FROM MAINE. PREFRONTAL AIRMASS IS VERY DRY WITH DEW PTS IN THE 30S AND 40S. THIS RESULTS IN VERY LITTLE TO ANY AVAILABLE INSTABILITY. IN ADDITION AS BLYR DEEPENS WINDS BECOME WEST AND LIMIT SURFACE CONVERGENCE. HENCE DRY WEATHER SHOULD PREVAIL THRU SUNSET. THIS IS TYPICALLY THE CASE AHEAD OF BACKDOOR FRONTS. IN ADDITION LATEST HRRR KEEPS SOUTHERN NEW ENGLAND DRY THRU 23Z FOLLOWED BY A FEW POSSIBLE SHOWERS/TSTMS ZIPPING ACROSS WESTERN CT THEREAFTER. HOWEVER THIS IS A VERY LOW PROB. OTHERWISE PREVIOUS FORECAST IN GOOD SHAPE AND NO MAJOR CHANGES PLANNED. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT...AN APPROACHING WARM FRONT WILL BE STALLED BY A LOW PRESSURE MOVING EAST INTO MAINE. ONCE THIS LOW PRESSURE MOVES QUICKLY EAST...A STRONG HIGH PRESSURE WILL START TO BUILD SOUTH ACROSS NORTHERN NEW ENGLAND. THIS HIGH PRESSURE WILL PUSH A BACK DOOR COLD FRONT INTO SOUTHERN NEW ENGLAND LATE TONIGHT INTO TUESDAY. WILL CONTINUE THE CHANCE FOR SOME SHOWERS INTO PARTS OF OUR REGION TONIGHT...AT LEAST UNTIL THE SUBSIDENCE BECOMES DOMINANT. THERE IS STILL SOME QUESTION AS TO WHEN THIS OCCURS... BUT THE LATEST THINKING IS IT MAY TAKE MOST OF THE NIGHT. COOLER OVERNIGHT TEMPERATURES ARE EXPECTED AS WINDS SHIFT TO THE NORTH AND NORTHEAST BEHIND THE BACK DOOR COLD FRONT. TUESDAY... BACK-DOOR COLD FRONT CONTINUES TO MOVE WEST AS A HIGH PRESSURE BUILDS OVER THE GULF OF MAINE. IT WILL TURN UNSEASONABLY COOL WITH ONSHORE FLOW OFF ROUGHLY UPPER 40S DEGREE WATER. LIKELY TO BE FAIRLY CLOUDY WITH A LONG FETCH OF EASTERLY FLOW UNDERGOING WEAK UPSLOPE AS OVERRUNNING REMAINS PREVALENT ALONG THE LOW- TO MID- LEVEL FRONTAL BOUNDARY SITUATED ACROSS AND TO THE WEST OF NEW ENGLAND. AS SUCH CANNOT COMPLETELY RULE OUT A STRAY SHOWER OR TWO. HOWEVER...EXPECTING MAINLY DRY CONDITIONS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * HIGH PRESSURE ON WEDNESDAY WITH UNSEASONABLE TEMPS ALONG E COAST * SEASONABLE TEMPS AND UNSETTLED WEATHER THURSDAY THROUGH THE WEEKEND * POTENTIALLY TURNING CHILLY WITH SHOWERS INTO EARLY NEXT WEEK MODELS AND CONFIDENCE... LATEST 00Z GUIDANCE IS IN AGREEMENT SHOWING A STRONG WEST COAST RIDGE WHICH WILL SUPPORT A BROAD/DEEP TROUGH SETTLING OVER THE ERN HALF OF THE CONUS. CLOSER AT HOME...HIGH PRESSURE WILL BE BUILDING IN THE GULF OF MAINE ON WEDNESDAY ALLOWING FOR DRY WEATHER. AS THE TROUGH MOVES TOWARDS NEW ENGLAND...A NORTH ATLANTIC RIDGE WILL HOLD STEADY...AND EVENTUALLY BLOCKS THE PROGRESSION OF THE TROUGH. A SFC LOW PRES WILL INTENSIFIES OVER THE MID-ATLANTIC AS SEVERAL STRONG SHORTWAVES DIG INTO THE BASE OF THE TROUGH. THAT LOW WILL THEN SLIDE UP THE EAST COAST FRIDAY...AND DRAG A COLD FRONT ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY. STILL A LOT OF TIMING ISSUES WITH THIS FORECAST BUT CONFIDENCE IS INCREASING THAT ASIDE FROM HIT OR MISS SHOWERS IN THE MEDIUM RANGE...THE LONG TERM WILL BE VERY UNSETTLED WITH POSSIBLE HEAVY RAIN/FLOODING ISSUES. SOLUTION SPREAD IS GRADUALLY NARROWING BUT GFS/GEFS ARE CONTINUING LEADING HGT FALLS INTO THE EAST FASTER THAN MOST OTHER GUIDANCE IN THE MID-LATE WEEK TIME FRAME. ALTHOUGH LATEST EC GUIDANCE IS ON THE SLOWER SIDE OF THE ENVELOPE WITH THE CMC ACTUALLY BEING IN THE MIDDLE OF THE SOLUTIONS AND ENSEMBLES. TRENDS AND CONTINUITY OVER MULTIPLE DAYS HAVE BEEN FAVORING SLOWER TIMING AS SUPPORTED BY THE AMPLIFIED NATURE OF THE APPROACHING TROUGH AS WELL AS BLOCKY PATTERN IN THE ATLANTIC...WHICH IS SUPPORTED WITH NAO TRENDING NEGATIVE. THEREFORE TRENDED THIS FORECAST TOWARDS THE ENSEMBLES AS WELL AS WPC. DETAILS... WEDNESDAY... HIGH PRESSURE WILL BUILD IN ACROSS THE GULF OF MAINE KEEPING MOST OF THE REGION DRY. TEMPS WILL BE SEASONABLE EXCEPT ALONG THE EASTERN COASTLINE AS ONSHORE FLOW WILL KEEP THE MARITIME AIR AROUND ON WEDNESDAY. HOWEVER STALLED BOUNDARY ACROSS CENTRAL NY MAY ALLOW FOR SOME ISO SHOWERS ACROSS WESTERN ZONES. THURSDAY INTO SATURDAY... STRONG ATLANTIC RIDGE TO THE EAST WILL SLOW THE PROGRESSION OF THE DIGGING TROUGH AND STALL IT JUST WEST OF THE REGION. HOWEVER BY THURSDAY...THE RIDGE WILL BREAK DOWN TEMPORARILY AS STRONG WESTERN RIDGE PUSHES THE TROUGH TOWARDS THE NORTHEAST. EXPECT SEVERAL WEAK WAVES TO DEVELOP AHEAD OF THIS TROUGH WHICH WILL APPROACH THE AREA. HIT OR MISS SHOWERS/T-STORMS POSSIBLE ON THURSDAY WITH MORE WIDESPREAD RAINFALL ON FRIDAY INTO SATURDAY. ALTHOUGH EXACT TIMING OF EACH WAVE IS STILL UNCERTAIN...IT APPEARS THAT THE BEST CHANCE FOR HIGHER PRECIP LOOKS TO BE FRIDAY NIGHT AS LOW PRESSURE SYSTEM DEVELOPS ALONG THE FRONT. STRONG LLJ AND INCREASING MOISTURE TRANSPORT SUPPORTS THE IDEA OF THE POSSIBILITY OF HEAVY RAINFALL. ESPECIALLY SINCE THE TROUGH IS TAPPING INTO DEEP GULF MOISTURE ALLOWING PWAT VALUES TO BE 3 STANDARD DEVIATIONS AWAY. INCREASING CONFIDENCE THAT HEAVY RAINFALL WILL OCCUR BUT THERE IS STILL SOME UNCERTAINTY ON EXACT TIMING...THEREFORE CONTINUED TO MENTION LIKELY POPS FOR FRIDAY INTO SATURDAY. ALSO A LOW CONFIDENCE ON FLOODING POTENTIAL AS FLASH FLOOD GUIDANCE IS APPROX 3 INCHES FOR MUCH OF THE AREA. IN FACT WPC IS FORECASTING 2.5 INCHES OF QPF. SO IF THIS FRONT STALLS/OR SLOWS DOWN ANY MORE WE MAY SEE SIGNIFICANT RAIN FALL AMOUNTS NEAR FLASH FLOOD GUIDANCE. A SEASONABLE BUT HUMID AIR MASS WILL OVERSPREAD THE REGION WITH SW FLOW TAPPING INTO THE GULF...ADVECTING HIGHER DEWPOINTS AHEAD OF THE TROUGH. FOG IS A POSSIBILITY ON WED NIGHT INTO THURSDAY AND AGAIN ON FRIDAY. HIGHS WILL GENERALLY TOP OFF IN THE UPPER 60S TO MID 70S WITH COOLER CONDITIONS ALONG THE COAST...ESP THE SOUTH COAST DUE TO SOUTHERLY FLOW. SUNDAY AND BEYOND... MODELS DIFFER ON THE TIMING ON THE EXIT OF THE SYSTEM LATE SATURDAY INTO SUNDAY. HAVE LOW CONFIDENCE ON WHEN THE FRONT WILL SWEEP EASTWARD AS A SLIGHT CHANGE IN THE PATH COULD LEAD TO A SIGNIFICANT CHANGE IN THE WEATHER FOR THE WEEKEND. OVERALL IT APPEARS THAT THE STRONG ATLANTIC HIGH PRESSURE WILL STALL THE SYSTEM JUST EAST OF THE REGION ON SUNDAY WITH AN UPPER LEVEL CUT OFF LOW FORMING. THIS LOW WILL KEEP THE REGION SHOWERY AS WELL AS COOLER DUE TO THE COLD CORE LOW WOBBLING OVER THE AREA. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/...HIGH CONFIDENCE. VFR. VERY LOW PROB OF AN ISOLATED SHOWER/TSTM NEAR BDL/BAF TOWARD 00Z. OTHERWISE DRY WEATHER PREVAILS. LIGHT/VARIABLE WINDS THIS MORNING BECOME WESTERLY THIS AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. LIGHT/VARIABLE WINDS BECOME WEST BY NOON. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE. EASTERLY WINDS. VFR WITH POSSIBLE MVFR CIGS ANTICIPATED. IFR OVERNIGHT IS POSSIBLE AS WINDS SWITCH BACK TO THE SOUTH. THURSDAY INTO FRIDAY...MODERATE CONFIDENCE. VFR FOR THURSDAY. CONDITIONS DETERIORATING FRIDAY TO IFR WITH INCREASING AREAL EXTENT OF SHRA AND POSSIBLE TSRA. SOUTHERLY WINDS ON THURSDAY CONTINUING INTO FRIDAY WITH GUSTS UP AROUND 25-30 KTS POSSIBLE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUESDAY. WINDS AND SEAS EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA THROUGH TODAY. WINDS INCREASE AS A BACK DOOR COLD FRONT MOVES FROM NORTHEAST TO SOUTHWEST TONIGHT. SMALL CRAFT ADVISORIES MAY AGAIN BE NECESSARY FOR A TIME TONIGHT INTO TUESDAY...THOUGH SEAS LOOK TO REMAIN BELOW 5 FEET. AT THIS POINT...DO NOT HAVE ENOUGH CONFIDENCE IN REACHING 25 KT GUSTS OR 5 FOOT SEAS TO ISSUE SMALL CRAFT ADVISORIES NOW. IT DOES REMAIN A POSSIBILITY...AND IS SOMETHING FUTURE SHIFTS WILL HAVE TO CONSIDER. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. HIGH PRESSURE WILL BUILD OVER THE EASTERN WATERS TUESDAY NIGHT AND INTO WEDNESDAY. EXPECT EASTERLY WINDS TO CONTINUE...ALLOWING FOR EASTERLY SWELL TO BUILD. FOG AND DRIZZLE POSSIBLE BY LATE WEDNESDAY AS FLOW SWITCH TO THE SOUTH. SCA MAY BE NEEDED FOR THE PERIOD. THURSDAY INTO FRIDAY...LOW CONFIDENCE. LINGER 5FT SEAS TO START INCREASING THROUGHOUT THE DAY WITH THE POSSIBILITY FOR A FEW SHOWERS ON THURSDAY. CONDITIONS DETERIORATE ON FRIDAY AS FRONT APPROACHES THE WATERS. SEAS AND WINDS WILL BUILD IN RESPONSE AS WELL AS HEAVY DOWNPOURS AND ISO THUNDER. SCA WILL BE NEEDED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...BELK/NOCERA/DUNTEN SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...BELK/NOCERA/DUNTEN MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
924 AM EDT MON MAY 12 2014 .SYNOPSIS...HIGH PRESSURE SLIDES OUT TO SEA OFF THE MID ATLANTIC COAST TODAY. AFTER A DELIGHTFULL SUNNY WARM DAY OUR WEATHER WILL TURN INCREASINGLY UNSETTLED AS THE WEEK PROGRESSES. LATE TODAY A BACK DOOR COLD FRONT WILL DROP SOUTH THROUGH THE REGION...STALLING ACROSS THE MID ATLANTIC STATES. BY MIDWEEK A LARGE FRONTAL SYSTEM IN THE GREAT LAKES WILL PUSH TOWARD THE EASTERN SEABOARD. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 915AM SOME HI CLOUDS ASSOC WITH CONVECTIVE DEBRIS FROM THE OVERNIGHT OHIO MCS WERE SPILLING OVER S PRTNS OF FCA...BUT THESE SHOULD THIN AND SHIFT SOUTH DURING THE REST OF THE DAY...UNTIL THE NEXT RIDGE ROLLER STARTS SPILLING CI/MID INTO FCA TWRD EVNG. TEMPS ARE A FEW DEG ABV CURRENT FCST...AND NUDGED MAXES 1-3 DEG BASED ON CURRENT TEMPS AND 06UTC MOS/MET. HRRR AND LOCAL WRF REFLECTIVITIES SUGGEST STILL THE POTENTIAL FOR SOME SHOWERS DEVELOPING ACROSS THE CATSKILLS. ALTHOUGH CONVECTIVE TEMP AT ALB ON MRNG SNDGS IS 103F. WILL CONT POPS BUT LOWERED TO SLGT CHC THERE. THE IR SATELLITE IMAGERY ALONG WITH SURFACE FRONT ANALYSIS REVEALS A BACKDOOR COLD FRONT HAS REACHED THE ST LAWRENCE VALLEY. ONE MCS THAT MOVED THROUGH OHIO INTO WV HAS DISSIPATED TO -SHRA AND CLOUDS...ANOTHER MOVING FM WI INTO MICHIGAN IS ALSO WEAKENING. COMBINATION OF THIS FRONT AND CONVECTIVE CLOUD DEBRIS WILL BRING AN INCREASE IN HIGH AND MID LEVEL MOISTURE ACROSS THE REGION LATE TODAY. CLOUD OPAQUENESS WILL VARY BUT ENOUGH SUNSHINE SHOULD RESULT IN A RATHER MILD AFTERNOON WITH HIGHS AT OR JUST ABOVE 80F FOR SEVERAL VALLEY LOCATIONS AND MAINLY 70S FOR THE REMAINDER OF THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... INTO THIS EVENING...EXPERIENTIAL HIRES REFLECTIVITY FORECASTS FROM SPC/HRRR/WRF SUGGEST WIDESPREAD CONVECTION DEVELOPS ALONG A WARM FRONT NEAR THE NY/PA BORDER WITH ADDITIONAL SHOWER ACTIVITY ALONG THE BACKDOOR COLD FRONT INTO THE DACKS. WE WILL INCREASE POPS INTO THE SLIGHT CHANCE TO CHANCE CATEGORY FOR THE REGION WITH THE HIGHER VALUES INTO THE CATSKILLS AND MID HUDSON VALLEY. OTHERWISE...THERE WILL BE A NOTABLE INCREASE AND THICKENING CLOUD COVER ACROSS THE REGION WITH NEAR SEASONABLE OVERNIGHT LOWS FOR THE REGION WITH SLIGHTLY COOLER VALUES ACROSS THE LAKE GEORGE SARATOGA REGION AND WESTERN NEW ENGLAND AS SURFACE HIGH ACROSS NORTHEAST CANADA IS EXPECTED TO BUILD AND CREST INTO NEW ENGLAND TONIGHT. TUESDAY THROUGH WEDNESDAY...CONFIDENCE IS NOT PARTICULARLY HIGH WITH RESPECT TO PLACEMENT OF HIGHER PROBABILITIES OF SHOWERS/TSTORMS. NCEP MODEL SUITE AND INTERNATIONAL GUIDANCE FAVOR AN IDEA OF A WARM FRONT LIFTING EAST-NORTHEAST ACROSS THE REGION WITH RISING HEIGHTS ALOFT FOR A MORE ANTICYCLONIC FLOW. FURTHERMORE...BEST LOW LEVEL JET FORCING AND THETA-E ADVECTIVE PROPERTIES REMAIN UPSTREAM FROM THE LOCAL SERVICE AREA WHICH TOO LIMITS A MORE ORGANIZED PRECIPITATION EVENT. SO WE WILL KEEP POPS INTO THE SLIGHT CHANCE FOR PORTIONS OF NEW ENGLAND TO CHC-SCT VALUES FOR EASTERN NY /THE HIGHER POP VALUES WEST OF THE HUDSON RIVER/. GIVEN THE CONSIDERABLE CLOUD COVER EXPECTED...WE WILL KEEP TEMPERATURES AROUND SEASONABLE LEVELS DURING THIS TIME FRAME WITH A BLEND OF THE WARMER MAV GUIDANCE AND COOLER MET GUIDANCE WHICH IS SOMEWHAT CLOSE TO THE EXPERIMENTAL ECMWF MOS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... STRONG RIDGING WILL BE DEPARTING THE EASTERN SEABOARD AT THE START OF THE EXTENDED PERIOD...WHILE A DIGGING TROUGH MOVES ACROSS THE UPPER MIDWEST/GREAT PLAINS AND TOWARDS THE GREAT LAKES AND OHIO VALLEY. INITIALLY...THE BEST FORCING FOR PRECIP WILL BE LOCATED WEST OF OUR AREA...AND WHILE SOME STRAY SHOWERS/THUNDERSTORMS CANT BE RULED OUT FOR WESTERN PARTS OF THE CWA...IT LOOKS TO BE MAINLY DRY AND MILD FOR WED NIGHT INTO THURSDAY. MINS ON WED NIGHT WILL BE IN THE 50S...WITH HIGHS ON THURSDAY WELL INTO THE 70S...AS 850 HPA TEMPS OF 12-14 DEGREES C WILL SUPPORT QUITE A WARM DAY. EVENTUALLY...THE UPPER LEVEL TROUGH AND ASSOCIATED SLOW MOVING SFC FRONT WILL MOVE CLOSER TO OUR AREA AND PASS THROUGH FROM WEST TO EAST FOR THE LATE WEEK PERIOD. THIS WILL LIKELY BRING A BAND OF HEAVY RAIN SHOWERS ACROSS OUR REGION FOR SOMETIME BETWEEN THURSDAY NIGHT AND SATURDAY MORNING. WITH PWAT VALUES SURGING TO AROUND 1.50 INCHES...A PERIOD OF HEAVY RAIN WILL BE POSSIBLE WHEN THE BEST FORCING MOVES ACROSS THE AREA. IN ADDITION...THERE MAY BE SOME EMBEDDED CONVECTIVE ELEMENTS WITHIN THE BAND OF HEAVY RAIN SHOWERS...AS SHOWALTER VALUES DROPPING BELOW ZERO SHOW THERE MAY BE ELEVATED INSTABILITY...WHICH CAN ALSO CONTRIBUTE TO THE HEAVY RAIN POTENTIAL. IT WILL BE MILD AHEAD OF THE FRONTAL BOUNDARY WITH MINS IN THE MID 50S TO LOW 60S FOR THURSDAY NIGHT...AND TEMPS NEAR 70 ON FRIDAY. COOLER TEMPS WILL START TO MOVE IN FROM THE WEST FOR FRIDAY NIGHT...AS THE BOUNDARY STARTS TO CROSS THE REGION...WITH MID 40S TO MID 50S...AND HIGHS ON SATURDAY MAINLY IN THE 60S. OVER THE WEEKEND...THERE MAY BE SOME LINGERING RAIN SHOWERS...AS THE UPPER LEVEL TROUGH WILL STILL BE MOVING ACROSS THE AREA. IT/S STILL HARD TO SAY IF THE CORE OF THE UPPER LEVEL CLOSES OFF AND IF IT WILL CROSS OVER OUR AREA...OR IF IT WILL JUST PASS OFF TO OUR NORTH. IN EITHER CASE...A CONTINUED CHANCE FOR RAIN SHOWERS IS JUSTIFIED...ALONG WITH COOLER TEMPS FOR SAT NIGHT INTO SUNDAY. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... A BATCH OF SCT-BKN MID LEVEL CLOUDS AROUND 10 KFT HAVE MOVED ACROSS THE REGION EARLY THIS MORNING. THESE CLOUDS HAVE STARTED TO THIN OUT AND MOVE AWAY FOR NOW...BUT SOME ADDITIONAL MID AND HIGH LEVEL CLOUDS CAN BE SEEN UPSTREAM ON IR SATELLITE IMAGERY. DURING THE DAY TODAY...SOME DIURNAL CU WILL DEVELOP...ALONG WITH THE AFOREMENTIONED PASSING MID AND HIGH LEVEL CLOUDS. VFR CONDITIONS WILL CONTINUE FOR ALL TERMINALS THROUGHOUT THE ENTIRE DAY. AT THIS POINT...THE THREAT FOR RAIN SHOWERS APPEARS TO BE MINIMAL...AS ANY ACTIVITY SHOULD REMAIN TO THE WEST OF THE HUDSON VALLEY TAF SITES...SO NO RAIN SHOWERS WILL BE MENTIONED IN THE TAF AT THIS TIME. WINDS FROM A W-SW DIRECTION WILL INCREASE TO ABOUT 5-10 KTS DURING THE BEST DAYTIME MIXING IN THE AFTN/EARLY EVENING. BY EVENING...MID LEVEL CLOUDS WILL INCREASE AND BECOME BKN FOR ALL SITES. WINDS WILL SWITCH TO A N-NW DIRECTION AS A BACKDOOR FRONTAL BOUNDARY MOVES THROUGH THE AREA...BUT WIND SPEEDS SHOULD DECREASE TO 5 KTS OR LESS FOR TONIGHT. THE THREAT FOR RAIN SHOWERS CONTINUES TO BE RATHER LOW...SO WILL CONTINUE WITH A DRY TAF FORECAST FOR TONIGHT WITH CONTINUED VFR CONDITIONS. OUTLOOK... TUESDAY THROUGH THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA. FRIDAY NIGHT THROUGH SATURDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA. && .FIRE WEATHER... RH VALUES TODAY WILL LOWER TO BETWEEN 25 AND 35 PERCENT AS HIGH TEMPERATURES REACH THE MID 70S TO LOWER 80S. WINDS ARE EXPECTED TO BE 10 MPH OR LESS. THERE IS A CHANCE OF SHOWERS DURING THE LATE AFTERNOON HOURS. THE RH LEVELS RECOVER TONIGHT TO BETWEEN 60 AND 90 PERCENT TONIGHT WITH A LIGHT WIND. THE CHANCE FOR SHOWERS WILL CONTINUE FOR THE ENTIRE REGION WITH THE HIGHER PROBABILITIES WEST OF THE HUDSON RIVER. && .HYDROLOGY... NO WIDESPREAD HYDROLOGIC ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. A MAINLY DRY AND WARM DAY IS EXPECTED TODAY WITH THE CHANCE FOR SHOWERS ON THE INCREASE LATE IN THE DAY. THIS CHANCE FOR SHOWERS WILL CONTINUE FOR MOST THE REGION WITH THE INCREASE PROBABILITY FOR SOME HEAVIER RAINFALL TOWARD THE END OF THIS WEEK. HOWEVER...ANY RAINFALL DURING THE EARLY AND MIDDLE PART OF THE WEEK WILL BE LIGHT AND HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. THE RAINFALL LATER IN THE WEEK COULD BE HEAVY AND WE WILL NEED TO WATCH NUMERICAL TRENDS CLOSELY. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...SNYDER NEAR TERM...BGM/SNYDER SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...FRUGIS FIRE WEATHER...BGM HYDROLOGY...BGM
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1046 AM EDT MON MAY 12 2014 .UPDATE... HI RES MODELS ARE STILL IN GOOD AGREEMENT WITH ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT THIS AFTERNOON BUT SOME DIFFERENCES IN TIMING. HRRR IS QUICKER WITH INITIALIZATION THAN THE LOCAL WRF...16Z COMPARED TO ABOUT 20Z. OVERALL THE POP FORECAST IS ON TRACK AND DID NOT ADJUST THE SLIGHT CHANCE/CHANCE FOR THIS AFTERNOON. I DID HOWEVER END UP PUSHING BACK THE INITIATION TO 17Z. FORECAST DEW POINTS WERE A LITTLE ON THE LOW SIDE SO INCREASED THEM INTO THE AFTERNOON. 11 && .PREV DISCUSSION... /ISSUED 740 AM EDT MON MAY 12 2014/ SHORT TERM /TODAY THROUGH TUESDAY/... WEAK UPPER-LEVEL RIDGING CONTINUES OVER THE REGION TODAY...THEN BEGINS SHIFTING EAST INTO THE WESTERN ATLANTIC TUESDAY. THE RIDGE DOES NOT APPEAR TO BE DOMINANT ENOUGH TO SHUT OFF ALL CHANCES FOR CONVECTION BUT SHOULD LIMIT COVERAGE TO SCATTERED AT BEST AND DIURNALLY ORIENTED. MID-LEVEL LAPSE RATES AROUND 6DEGC/KM OR LESS KEEP INSTABILITY LIMITED WITH ANY THUNDERSTORMS EXPECTED TO REMAIN BELOW SEVERE LIMITS. FOR EARLY THIS MORNING...LOW-LEVEL MOISTURE AND MOIST SOILS ONCE AGAIN CONTRIBUTING TO AREAS OF FOG WITH PATCHY AREAS OF DENSE FOG. COVERAGE IS LESS THAN YESTERDAY MORNING AND IS EXPECTED TO REMAIN SO THIS MORNING AND IT DOES NOT APPEAR THAT THE AREAL COVERAGE OF VISIBILITIES BELOW 1/4 MILE WOULD BE SUFFICIENT FOR A DENSE FOG ADVISORY. 20 LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... LARGE HIGH AMPLITUDE H5 TROUGH OVER CENTRAL US FCST TO CONTINUE PROGRESSING SLOWLY EASTWARD REST OF THE WEEK. BY 12Z WED...TROUGH AXIS WILL STILL BE CENTERED ALONG 90W LONGITUDE BUT SWLY FLOW ALOFT AND WARM/MOIST ADVECTION AHEAD OF IT WILL INCREASE ACROSS THE SE STATES BRINGING CLOUDS AND SOME SCT SHRA WITH IT. INSTABILITY QUITE HIGH OVER THE CENTRAL STATES. HOWEVER AS THE TROUGH PUSHES EAST EACH DAY...LOW LEVEL FLOW PROGGED TO WEAKEN AND INSTABILITY DECREASES SOME. BY 12Z THURSDAY WHEN THE FRONT ASSOCIATED WITH THE UPPER TROUGH MOVES INTO THE STATE...MLCAPE VALUES ONLY AROUND 250-500 J/KG AND 0-1KM BULK SHEAR ONLY 10-20KTS. COULD ALSO SEE UPSTREAM CONVECTION ALONG THE CENTRAL GULF COAST AGAIN INHIBIT STORM DEVELOPMENT INLAND. DEEP SHEAR PROGGED TO REMAIN QUITE STRONG WITH 0-6KM BULK SHEAR 12Z THUR 40-50KTS...INDICATIVE OF STRONG TEMP GRADIENT ALONG FRONT AS WELL. EVEN WITH STRONG DEEP SHEAR...WITH LACK OF INSTABILITY AND LOW LEVEL SHEAR...SVR STORMS APPEAR UNLIKELY AT THIS TIME. COULD SEE PERIOD OF MDT TO HEAVY RAIN ON THURS...BUT WITH SLOW PROGRESSIVE NATURE OF SYSTEM...APPEARS ANY ONE AREA SHOULD NOT SEE MORE THAN 2 INCHES THROUGH 12Z FRI. AFTER FRONT AND ASSOCD SHORT WAVE PUSH THROUGH...UPPER TROUGH SLOW TO PUSH OUT OF EASTERN CONUS. ANOTHER WAVE IN NW FLOW OVER THE CENTRAL PLAINS PROGGED TO MOVE INTO THE TN VALLEY SAT. QUITE A BIT OF DISCREPANCY BETWEEN MED RANGE MODELS /00Z GFS...ECMWF AND CMC/ ON THIS FEATURE...ECMWF SOMEWHAT SLOWER. WITH DRY AIR MASS EXPECTED AS THIS SECOND WAVE APPROACHES...HAVE BACKED OFF A LITTLE ON POPS. NW FLOW CAN BE TRICKY IN THE WARM SEASON SO WILL NEED TO MONITOR THIS. INSTABILITY PROGGED TO BE LOW BUT NOT ZERO. SNELSON AVIATION... 12Z UPDATE... WIDE RANGE OF LIFR TO VFR CONDITIONS...MAINLY DUE TO FOG..CURRENTLY ACROSS THE FORECAST AREA. MVFR VISIBILITIES PREDOMINATE WITH SCATTERED VFR AND A FEW LOCAL LIFR VISIBILITIES. EXPECT MAINLY VFR CONDITIONS AFTER 14Z OUTSIDE OF ISOLATED TO SCATTERED CONVECTION EXPECTED BETWEEN 18-02Z. SCATTERED CUMULUS DEVELOPMENT AROUND 2-3KFT BY 14 THROUGH 18Z... LIFTING TO 4-5KFT AFTER 18Z. WINDS WILL BE LIGHT..LESS THAN 5KTS...AND SOMEWHAT VARIABLE IN DIRECTION THROUGH 14Z BUT WILL FAVOR SOUTHEAST. WIND SPEEDS WILL INCREASE TO 5-9KTS AFTER 14Z WITH DIRECTION VARYING BETWEEN SOUTHWEST AND SOUTHEAST. //ATL CONFIDENCE...12Z UPDATE... MEDIUM TO HIGH CONFIDENCE ON ALL ELEMENTS. 20 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 89 65 88 64 / 30 20 30 10 ATLANTA 87 68 86 66 / 30 20 30 10 BLAIRSVILLE 84 61 83 62 / 30 20 30 20 CARTERSVILLE 87 63 86 65 / 30 20 30 30 COLUMBUS 91 68 90 67 / 30 20 30 10 GAINESVILLE 85 66 84 65 / 30 20 30 20 MACON 90 65 89 65 / 30 20 30 10 ROME 87 63 86 63 / 30 20 30 30 PEACHTREE CITY 89 64 88 63 / 30 20 30 10 VIDALIA 90 67 89 68 / 30 20 30 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...11 LONG TERM....NLISTEMAA AVIATION...11
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1052 AM CDT MON MAY 12 2014 .DISCUSSION... 328 AM CDT AMONG THIS MORNING`S MANY RECAST CHALLENGES ARE TEMPS TODAY...PRECIP AND CONVECTIVE TRENDS THROUGH TONIGHT...RAIN CHANCES LATER IN THE WEEK WITH SECONDARY CYCLONE...AND MAGNITUDE OF COLD AIR MASS LATER THIS WEEK. IT IS FUNNY HOW OFTEN CONFIDENCE IN A FORECAST DECREASES AS THE FORECAST TIME NEARS. LAST NIGHT AT THIS TIME WAS FAIRLY CONFIDENT THAT CONVECTION TO OUR WEST WOULD DISSIPATE BEFORE MAKING IT INTO OUR AREA WITH THE FOCUS SHIFTING NORTH INTO WISCONSIN...BUT PLAYING A GAME OF METEOROLOGICAL CHICKEN WITH THE MCS OVER IOWA THAT CONTINUES TO CHARGE EAST TOWARD THE MISSISSIPPI RIVER EARLY THIS MORNING AND AM GROWING INCREASINGLY TEMPTED TO FLINCH AND BUMP UP POPS SOME THIS MORNING. THE ATMOSPHERE OVER NORTHERN ILLINOIS WAS SIGNIFICANTLY MODIFIED AND STABILIZED BY SUNDAY EVENING`S CONVECTION...BUT CONTRASTING THE 00Z SOUNDINGS FROM DVN AND ILX SHOW JUST HOW NEARBY THE CONVECTIVELY MOIST AND UNSTABLE AIR MASS LIES. THE COMPOSITE SECONDARY WARM FRONT/OUTFLOW BOUNDARY EXTENDING ROUGHLY FROM KLAF TO JUST SOUTH OF THE QUAD CITIES IS LIFTING NORTH AND/OR WASHING OUT WITH WINDS ACROSS NORTHERN ILLINOIS VEERING MORE SOUTHERLY AND HIGHER DEWPOINTS CREEPING NORTHWARD. SHORT RANGE GUIDANCE IS STRONGLY DIVIDED IN THE HANDLING OF THE MCS OVER IOWA...WITH ONE CAMP SHOWING A FAIRLY RAPID DEMISE OVER THE NEXT SEVERAL HOURS WITH ONLY SCTD SHRA/ISOLD TSRA POTENTIALLY MAKING IT INTO NW CWA WHILE ANOTHER CAMP OF MODELS IS MORE AGGRESSIVE IN BRINGING STORMS EAST ACROSS THE CWA THROUGH THE MORNING. THE IMPLICATIONS OF HOW THIS SCENARIO EVOLVES ARE HUGE FOR TEMPS...WINDS...AND SUBSEQUENT CONVECTIVE CHANCES WITH THE COLD FRONT. CONFIDENCE IS NOT HIGH...BUT LEANING TOWARD STAYING THE COURSE WITH THINKING FROM PREVIOUS FORECASTS WHICH SUGGEST A QUICK WEAKENING TREND WITHOUT MUCH CONVECTION MAKING IT FAR INTO OUR CWA. RECENT REGIONAL RADAR AND SATELLITE TRENDS SEEM TO FINALLY BE SUPPORTING THIS LINE OF THINKING WITH CLOUD TOPS BEGINNING TO QUICKLY WARM WITH DECREASING COVERAGE AND INTENSITY OF THE STORMS. SEVERAL MODELS ARE HINTING AT THE POTENTIAL FOR ADDITIONAL SCTD CONVECTION DEVELOPING IN THE WARM/MOIST/UNSTABLE AXIS EXTENDING FROM DOWNSTATE IL NNE INTO NNW INDIANA. DESPITE LEANING TOWARD THE DRIER SOLUTIONS FOR TODAY WILL BE MAINTAINING CHANCE POPS ACROSS THE CWA TO ALLOW FOR EITHER THE IOWA MCS PERSISTING LONGER AND/OR MOIST/UNSTABLE AXIS THIS AFTERNOON. HIGH TEMPS AND EVEN GUSTINESS OF THE WINDS TODAY WILL HINGE ON CLOUD COVER AND PRECIP. IF THE MCS CONTINUES TO QUICKLY WEAKEN AND DEBRIS CLOUDINESS DISSIPATE...THEN IT SHOULD ALLOW FOR PARTIAL SUNSHINE AND WHICH COULD SEND TIMES CLIMBING WELL INTO THE 80S AND ABOVE OBJECTIVE GUIDANCE. THIS IS THE CURRENT FORECAST AND RATHER THAN FLIP ONLY TO HAVE THE DAY SHIFT HAVE TO FLOP WILL STAY THE COURSE WITH ABOVE GUIDANCE HIGHS AND IF IT BECOMES CLEAR THAT CLOUDS WILL STICK AROUND THE DAY SHIFT CAN BACK OFF ON TEMPS WITH A MORNING UPDATE. THERE ARE A HANDFUL OF CONVECTIVE ALLOWING MODELS SHOWING A RELATIVE MIN IN CONVECTIVE REDEVELOPMENT OVER IOWA TONIGHT FOLLOWING THE STABILIZING EFFECTS OF CURRENT MCS...BUT WITH GREATER NUMBER OF MODELS SUPPORTING RE-DEVELOPMENT PLAN TO HANG ON TO LIKELY POPS TONIGHT AS THE FRONT MOVES EAST TOWARD THE AREA. MORE MARGINAL AND UNIDIRECTIONAL SHEAR PROFILES AND DECREASING INSTABILITY AT NIGHT BOTH WOULD ARGUE FOR STORMS MOVING INTO THE AREA TONIGHT TO BE IN A WEAKENING PHASE WITH SEVERE THREAT DECREASING WITH TIME AND EASTWARD EXTENT TONIGHT. RAIN COULD LINGER INTO TUESDAY...ESPECIALLY IN THE MORNING AND OVER THE EASTERN CWA BEFORE BETTER FORCING PUSHES OFF TO THE EAST AND DRIER AIR MOVES IN. TUESDAY AFTERNOON COULD BE SALVAGEABLE FOR MANY AREAS WITH NEAR NORMAL HIGHS AND LIKELY AN END TO THE PRECIPITATION. LATER WEDNESDAY INTO THURSDAY GUIDANCE REALLY RUNS THE GAMUT IN HANDLING OF THE SECONDARY SHORTWAVE TROUGH ROUNDING THE BASE OF THE DEEP UPPER TROUGH THAT WILL BECOME ESTABLISHED OVER EASTERN NOAM. WPC PREFERRED MODEL CHOICE WAS THE 00Z ECMWF WHICH IS CLOSE TO THE MIDDLE OF THE ROAD OF POSSIBLE SOLUTIONS AND SAW NO REASON TO DEVIATE FROM THIS LINE OF THINKING. ASSUMING THE ECMWF VERIFIES A SECONDARY WAVE OF LOW PRESSURE WILL TRACK NORTHEAST ALONG THE PASSING COLD FRONT AND PRODUCE A PERIOD OF RAIN/SHOWERS...MAINLY SOUTHEASTERN HALF OF THE CWA. REMARKABLY SOME GUIDANCE HAS 850MB TEMPS DROPPING TO 0 TO -2C DURING THE PRECIP WHICH WHILE COLD IS PROBABLY NOT COLD ENOUGH FOR ANY MIXED PRECIP GIVEN THE TIME YEAR BUT PERILOUSLY CLOSE. GIVEN THE MODEL SPREAD EARLY IN THE PERIOD PROBABLY NOT SURPRISING THAT THERE IS SUBSTANTIAL SPREAD IN THE INTENSITY OF THE UPPER TROUGH/LOW LATE IN THE WEEK AND SUBSEQUENT TEMPS WITH FAR MORE AMPLIFIED AND COLD SOLUTION IN THE ECMWF SUPPORTIVE OF TEMPS COLDER THAN WHAT OUR CURRENT FORECAST BUT WITH SO MUCH UNCERTAINTY SO NO REASON TO STRAY FROM THE BLENDED MODEL CONSENSUS. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * GUSTY SOUTHERLY TO SOUTH-SOUTHWESTERLY WINDS TODAY. * TIMING AND CHANCES OF ADDITIONAL TSRA TODAY AND TONIGHT. * LOWER MVFR CIGS POSS TUESDAY MORNING. KREIN //DISCUSSION...UPDATED 16Z... ADDED TEMPO GROUP FOR TSRA TO ALL TAFS FOR EARLY THIS AFTERNOON. FOLLOWING AN MCV OVER ERN IOWA AND TIMING WOULD BRING ANY ASSOCIATED THUNDERSTORM ACTIVITY TO THE RFD AREA BY ARND 18Z AND THE CHICAGO AREA BY ARND 19-20Z. THE CONVECTIVE ACTIVITY CURRENTLY ASSOCIATED WITH THE SYSTEM IS ON A WEAKENING TREND...BUT IT WILL BE MOVING INTO A MORE CONVECTIVELY FAVORABLY ENVIRONMENT OVER THE NEXT COUPLE HOURS...SO WILL NEED TO BE MONITORED CLOSELY. KREIN UPDATED 12Z... THE CHANCES AND TIMING OF ADDITIONAL CONVECTIVE ACTIVITY WILL BE THE PRIMARILY WEATHER CONCERN ACROSS THE NORTHERN ILLINOIS TERMINALS AGAIN TODAY AND TONIGHT. THE THREAT FOR CONVECTIVE ACTIVITY OVER OR NEAR THE TERMINALS THROUGH THE DAY TODAY APPEARS LOW...BUT NOT ZERO. A WARM...MOIST AND UNSTABLE AIR MASS WILL BE IN PLACE ACROSS THE AREA TODAY. HOWEVER...WITH THE LACK OF ANY SIGNIFICANT TRIGGER MECHANISM TO GET CONVECTION GOING...IT APPEARS THAT ANY ACTIVITY THAT DEVELOPS ACROSS THE AREA DURING THE DAY WILL BE OF FAIRLY LOW AREAL COVERAGE. WITH THIS IN MIND...I WILL CONTINUE TO KEEP THE MENTION OF THUNDER OUT OF THE TAF THROUGH THE DAY. THE NEXT MAIN THREAT FOR A PERIOD OF POSSIBLY MORE WIDESPREAD SHOWERS AND STORMS WILL TONIGHT AHEAD OF AN APPROACHING COLD FRONT. WINDS ARE EXPECTED TO BE GUSTY UP AROUND 25 KT OUT OF THE SOUTH- SOUTHWEST DURING THE DAY TODAY. A COLD FRONT WILL THEN SHIFT ACROSS THE AREA AROUND DAYBREAK ON TUESDAY. THIS WILL RESULT IN A WESTERLY WIND SHIFT ACROSS THE AREA...ALONG WITH THE POTENTIAL FOR SOME LOWER CIGS TO MOVE ACROSS THE AREA. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH CONFIDENCE IN WIND FORECAST. * LOW CONFIDENCE CONVECTIVE TIMING AND COVERAGE TODAY AND TONIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... * TUESDAY NIGHT...VFR. * WEDNESDAY...SLIGHT CHANCE OF PM SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY AND SUNDAY...DRY/VFR. KJB && .MARINE... 323 AM CDT AN AREA OF LOW PRESSURE ACROSS THE MID MISSOURI VALLEY EARLY THIS MORNING WILL TRACK NORTHEASTWARD TOWARDS LAKE SUPERIOR BY TONIGHT. AS THIS OCCURS...AN ASSOCIATED WARM FRONT IS EXPECTED TO LIFT NORTHWARD UP THE LAKE THROUGH TONIGHT. AREAS OF FOG...POTENTIALLY DENSE WILL BE LIKELY ACROSS PORTIONS OF THE LAKE TODAY AND TONIGHT AS THIS FRONT...AND THE ACCOMPANYING VERY MOIST AIR MASS MOVES OVER THE COOL LAKE WATERS. A MARINE DENSE FOG ADVISORY MAY BE NEEDED. THE OTHER CONCERN WILL BE THE WINDS TODAY AND TONIGHT WITH THIS WARM FRONT LIFTING UP THE LAKE. THE WINDS SOUTH OF THIS WARM FRONT WILL BECOME SOUTHERLY AROUND 25 KT TODAY...WHILE NORTH OF THE WARM FRONT...SOME STOUT EASTERLY WINDS WILL BE LIKELY. THESE GUSTY SOUTHERLY WINDS WILL RESULT IN LIKELY RESULT IN NEAR SMALL CRAFT ADVISORY WINDS OVER THE ILLINOIS AND INDIANA NEAR SHORE WATERS BY MIDDAY. HOWEVER...IN SPITE OF THIS...I HAVE OPTED TO HOLD OFF ON AN ADVISORY DUE TO THERE BEING SOME QUESTION AS TO EXACTLY HOW STRONG THE WINDS WILL BE OVER THE NEAR SHORE WATERS. IN ADDITION...WITH THE OFFSHORE COMPONENT...WAVES WILL LIKELY NOT BUILD OVER 4 FT IN THE NEAR SHORE WATERS. THE POTENTIAL IS CERTAINLY THERE FOR 25+ KT OFFSHORE FLOW TODAY...WITH THE POTENTIAL NEED FOR AN UPGRADE TO A SMALL CRAFT ADVISORY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM MONDAY. DENSE FOG ADVISORY...LMZ567-LMZ669-LMZ671-LMZ868-LMZ870-LMZ872 UNTIL 3 PM MONDAY. DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 1 AM TUESDAY. && $$ 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
  [top] Area Forecast Discussion National Weather Service Lincoln IL 949 AM CDT Mon May 12 2014 .DISCUSSION... ISSUED 949 AM CDT Mon May 12 2014 Another warm and humid day is unfolding across central Illinois, as 14z/9am temps have already risen well into the 70s. The area remains convection-free for the time being, but as weak capping is broken over the next couple of hours widely scattered thunderstorms will begin to develop. Enhanced Cu field is currently evident on visible satellite imagery from Arkansas northeastward across the eastern half of the KILX CWA. Latest mesoanalysis from SPC indicates deep layer moisture convergence maximized from southeast Missouri into southeast Illinois, where HRRR shows scattered thunderstorm development between now and 18z. Elsewhere around central Illinois, convection will likely remain more isolated in nature until later this afternoon when cold front begins to approach from the west. Front is still progged to reach the area after dark tonight, so best chances for widespread convection will likely hold off until late afternoon/early evening in the Illinois River Valley, then further east across the remainder of the area overnight. Barnes && .AVIATION... ISSUED 641 AM CDT Mon May 12 2014 VFR conditions will start each TAF most of the day. Mid and high clouds will remain over the area this morning and then around noon cigs will fall to around 6kft at all TAF sites, as CU thickens ahead of the cold front. Thunderstorms are expected to develop late this afternoon to the west of the area and then move east into the area...affecting each TAF site...tonight. Lots of uncertainty on timing of the next round of storms...so kept VCTS in TAFs as previously forecasted. Did add a TEMPO group at the end as best first guess on when storms will on station. Winds will be southerly through the period with gusty conditions during the day today. Auten && .PREV DISCUSSION... ISSUED 330 AM CDT Mon May 12 2014 SHORT TERM...Today through Wednesday night Quiet conditions temporarily returned to central and southeast IL early this morning as convection with MCS had shifted east of IL into east central IN and Ohio, and a larger area of convection with a couple MCSS was over WI/IA and eastern KS into far nw MO. Cold front over western IA and eastern KS into central OK and west Texas while warm front was over northern IL. Moist dewpoints in the upper 60s over central and southern IL and mild temps 69-75F with sse winds in warm sector. Strong upper level trof over the Rockies with 557 dm 500 mb low over western CO to eject surface 1002 mb low over east central KS ne into the upper MS river valley by midnight tonight and swing a cold front east across IL overnight. 00Z models are in fair agreement with timing of this cold frontal passage. Isolated to scattered thunderstorms to develop during today especially this afternoon over the IL river valley as air mass destabilizes with CAPES increasing to 1500-2500 J/kg. Best chances of convection will be tonight with slight chance of severe storms nw of IL river this evening. Best risk of severe supercells with possible tornados form mid afternoon into mid evening will be over eastern IA northern MO into far nw IL and sw WI where stronger wind shear will be. Another very warm and humid day with highs in the mid 80s with a few areas se of IL river even seeing upper 80s with enough sunshine. Cold front to pass east into Indiana early Tue morning and have highest chances of convection over eastern IL Tue morning and diminishing to the west. SPC has 5% risk of severe storms Tue from Wabash river east so mostly over IN. Highs Tue range from mid 60s from I-55 west to the low to mid 70s east of I-57 in eastern IL. Looks like a lull in shower chances over central IL Tue night though kept chances of showers over southern areas especially se IL closer to frontal boundary stalling just se of IL. Leaned on wetter ECMWF and NAM models with surface low ejecting ne Wed and passing just se of IL while GFS appears too weak and far to the east with its QPF fields. Have isolated thunderstorms Wed se of I-70 while SPC keeps slight risk of severe storms se of IL Wed. Showers to diminish from the west during Wed night with highest chances near the IN border Wed evening. Cooler highs in the upper 50s and lower 60s Wed and these cooler readings to linger Thu. LONG TERM...Thursday through Monday Medium to long range models and their ensembles continues to advertise large upper level trof over the MS river valley Thu and upper level low lifting north of the Great Lakes this weekend while trof shifts east into the eastern states. As core of coolest 850 mb air shifts ne of central IL during the weekend with upper level low, expect temperatures to modify during this weekend into early next week but generally still stay a below normal. Cool nights in the low to mid 40s Thu night through Sat night. Instability light rain showers possible Thu & Fri especially during the afternoon and early evening with disturbances pivoting thru the nearby upper level trof. Isolated light showers still possible Sat sw of I-74 while dry conditions then prevail from Sat night through Monday. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
708 AM CDT MON MAY 12 2014 .SYNOPSIS... ISSUED AT 321 AM CDT MON MAY 12 2014 LOW PRESSURE MOVING INTO WESTERN IA WILL LIFT NORTHEAST AS COLD FRONT SWEEPS ACROSS THE STATE BY LATE TONIGHT. PATTERN WILL CHANGE TO A MUCH COOLER REGIME AS CANADIAN HIGH PRESSURE DOMINATES THROUGH THE REST OF THE WORK WEEK. && .UPDATE... ISSUED AT 704 AM CDT MON MAY 12 2014 UPDATED FORECAST FOR MINOR ADJUSTMENTS TO PRECIP TRENDS AND TEMP TRENDS. ALSO FOR REMOVAL OF HEADLINES. && .SHORT TERM /TODAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 TWO PROBLEMS TODAY ARE BOTH WITH CONVECTION THE EARLY MORNING CONVECTION WILL BE AN ISSUE WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL MOVING INTO ALREADY SATURATED AREAS. THIS IS ASSOCIATED WITH A WEAK WAVE IN THE FLOW THAT IS LIFTING NORTHEAST ACROSS THE STATE. ADDITIONAL DEVELOPMENT IS LIKELY OVER THE SOUTHEAST HALF OF THE STATE WITH THE COLD FRONT PROGRESSING EAST. THE HRRR HAS WHAT SEEMS TO BE A REASONABLE HANDLE ON THIS. SEVERITY WILL DEPEND ON HOW MUCH RECOVERY WE CAN ACHIEVE AFTER THE MORNING CONVECTION. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 PRECIPITATION WILL MOVE OUT OF THE STATE BY 06Z AS THE PATTERN CHANGES FROM A SOUTHWEST FLOW TO A NORTHWEST FLOW. CANADIAN HIGH PRESSURE WILL DOMINATE THE WEEKS WEATHER WITH TEMPERATURES WELL BELOW NORMAL. WILL POTENTIAL NEED TO CONSIDER SOME FROST WORDING LATER IN THE WEEK, BUT CERTAINTY IS NOT THERE AT THIS TIME BECAUSE OF THE POTENTIAL FOR SOME CLOUD COVER. IT WILL LIKELY TAKE UNTIL THE WEEKEND BEFORE THE COOL HIGH PRESSURE MOVES OFF TO THE EAST. WARMING AND AN INCREASED CHANCE FOR THUNDERSTORMS IS EXPECTED LATER IN THE WEEKEND. && .AVIATION...12/12Z ISSUED AT 544 AM CDT MON MAY 12 2014 LOW PRESSURE OVER SERN NEBRASKA WILL MOVE NORTHEAST THROUGH WESTERN IA AND INTO MINNESOTA BY THIS EVENING. TRAILING COLD FRONT WILL MOVE EAST ACROSS THE TAF SITES LATER TODAY AND THIS EVENING. AREA OF THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THE COLD FRONT TODAY...WITH MVFR STRATUS SPREADING INTO THE AREA BEHIND THE COLD FRONT. MVFR CIGS WILL HOLD THROUGH THE NIGHT. OUTLOOK...HIGH PRESSURE WILL BUILD INTO THE AREA TUE AND WED AND DOMINATE THE WEATHER THROUGH THE WORK WEEK. SEVERAL MINOR DISTURBANCES WILL MOVE THROUGH...BUT CONDITIONS WILL REMAIN VFR. && .HYDROLOGY... ISSUED AT 704 AM CDT MON MAY 12 2014 THUNDERSTORMS CONTINUE TO LIVE NORTHEAST ACROSS THE STATE AHEAD OF THE APPROACHING COLD FRONT. THE HEAVIER STORMS WILL MOVE OVER AREAS THE DID NOT RECEIVE A LOT OF RAIN DURING THE PAST 24 HOURS. THE RAIN IS EXPECTED TO END BY MID MORNING. ADDITIONAL SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...ESPECIALLY EAST OF INTERSTATE 35. THEY ARE NOT EXPECTED TO PRODUCE FLASH FLOODING HOWEVER. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MS MAY 14 SYNOPSIS...MS MAY 14 SHORT TERM...MS MAY 14 LONG TERM...MS MAY 14 AVIATION...MS MAY 14 HYDROLOGY...MS MAY 14
AREA FORECAST DISCUSSION
NWS DES MOINES IA
547 AM CDT MON MAY 12 2014 .SYNOPSIS... ISSUED AT 321 AM CDT MON MAY 12 2014 LOW PRESSURE MOVING INTO WESTERN IA WILL LIFT NORTHEAST AS COLD FRONT SWEEPS ACROSS THE STATE BY LATE TONIGHT. PATTERN WILL CHANGE TO A MUCH COOLER REGIME AS CANADIAN HIGH PRESSURE DOMINATES THROUGH THE REST OF THE WORK WEEK. && .SHORT TERM /TODAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 TWO PROBLEMS TODAY ARE BOTH WITH CONVECTION THE EARLY MORNING CONVECTION WILL BE AN ISSUE WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL MOVING INTO ALREADY SATURATED AREAS. THIS IS ASSOCIATED WITH A WEAK WAVE IN THE FLOW THAT IS LIFTING NORTHEAST ACROSS THE STATE. ADDITIONAL DEVELOPMENT IS LIKELY OVER THE SOUTHEAST HALF OF THE STATE WITH THE COLD FRONT PROGRESSING EAST. THE HRRR HAS WHAT SEEMS TO BE A REASONABLE HANDLE ON THIS. SEVERITY WILL DEPEND ON HOW MUCH RECOVERY WE CAN ACHIEVE AFTER THE MORNING CONVECTION. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 PRECIPITATION WILL MOVE OUT OF THE STATE BY 06Z AS THE PATTERN CHANGES FROM A SOUTHWEST FLOW TO A NORTHWEST FLOW. CANADIAN HIGH PRESSURE WILL DOMINATE THE WEEKS WEATHER WITH TEMPERATURES WELL BELOW NORMAL. WILL POTENTIAL NEED TO CONSIDER SOME FROST WORDING LATER IN THE WEEK, BUT CERTAINTY IS NOT THERE AT THIS TIME BECAUSE OF THE POTENTIAL FOR SOME CLOUD COVER. IT WILL LIKELY TAKE UNTIL THE WEEKEND BEFORE THE COOL HIGH PRESSURE MOVES OFF TO THE EAST. WARMING AND AN INCREASED CHANCE FOR THUNDERSTORMS IS EXPECTED LATER IN THE WEEKEND. && .AVIATION...12/12Z ISSUED AT 544 AM CDT MON MAY 12 2014 LOW PRESSURE OVER SERN NEBRASKA WILL MOVE NORTHEAST THROUGH WESTERN IA AND INTO MINNESOTA BY THIS EVENING. TRAILING COLD FRONT WILL MOVE EAST ACROSS THE TAF SITES LATER TODAY AND THIS EVENING. AREA OF THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THE COLD FRONT TODAY...WITH MVFR STRATUS SPREADING INTO THE AREA BEHIND THE COLD FRONT. MVFR CIGS WILL HOLD THROUGH THE NIGHT. OUTLOOK...HIGH PRESSURE WILL BUILD INTO THE AREA TUE AND WED AND DOMINATE THE WEATHER THROUGH THE WORK WEEK. SEVERAL MINOR DISTURBANCES WILL MOVE THROUGH...BUT CONDITIONS WILL REMAIN VFR. && .HYDROLOGY... ISSUED AT 321 AM CDT MON MAY 12 2014 THEN ENVIRONMENT REMAINS FAVORABLE FOR HEAVY RAINFALL AT LEAST THROUGH EARLY THIS MORNING WITH THE LOW PRESSURE AND COLD FRONT CLOSE. DECENT DEVELOPMENT OVER WESTERN IOWA AND TO THE SOUTHWEST OF THE STATE WILL MOVE NORTHEAST THROUGH THE STATE THIS MORNING. MOST VULNERABLE AREAS WILL BE THE SOUTHWEST AND SOUTH CENTRAL AREAS...AND SOME IN THE NORTHWEST...WHERE RAINFALL TOTALS HAVE BEEN IN THE 2 TO 3 INCH RAIN LOCALLY WITH SOME HIGHER TOTALS. ADDITIONAL THUNDERSTORM DEVELOPMENT LATER IN THE DAY IS LIKELY TO BE EAST OF THESE AREAS AND TO NOW ANTICIPATE EXTENDING THE FLASH FLOOD WATCH AT THIS TIME. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR ADAIR-ADAMS- AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-CASS- CERRO GORDO-CRAWFORD-DALLAS-EMMET-FRANKLIN-GREENE-GRUNDY-GUTHRIE- HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-MADISON-MARSHALL-PALO ALTO-POCAHONTAS-POLK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-UNION- WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SYNOPSIS...MS MAY 14 SHORT TERM...MS MAY 14 LONG TERM...MS MAY 14 AVIATION...MS MAY 14 HYDROLOGY...MS MAY 14
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
610 AM CDT Mon May 12 2014 ...Updated aviation discussion... .SHORT TERM...(Today and tonight) ISSUED AT 200 AM CDT MON MAY 12 2014 A few high based showers will be possible across west central and portions of southwest Kansas through late morning as the closed off upper level low to our west opens up while moving east into the Western High Plains today. Much colder air aloft surging southward into the region will increase lapse rates aloft supporting the potential for a few isolated showers. Otherwise, tranquil conditions are likely Monday afternoon through Monday night as drier air continues move down into the high plains of western Kansas. Much cooler temperatures are on the way today as colder air surges southward into western Kansas through the period. The NAM/GFS show the H85 isotherm slipping southward nosing into west central and the I-70 corridor with H85 temperatures near 5C closer to the Oklahoma border. With low level stratus lingering through at least mid day, look for highs struggling to reach the 50s(F) across west central and central Kansas near the I-70 corridor with the upper 50s(F) to near 60F in south central Kansas. .LONG TERM...(Tuesday through Sunday) ISSUED AT 246 AM CDT MON MAY 12 2014 An upper level trough will slowly move east across western Kansas late Tuesday and Wednesday. Mid level moisture under the cool upper low appears to increase late Wednesday as 700mb warm air advection develops ahead of a north to south oriented upper level jet located on the western side of this upper level trough. Precipitation chances still appear small mid week, however increasing clouds are expected which may limit how warm temperatures will be mid week. At this time will lean towards the latest guidance for highs on Wednesday with temperatures mainly in the mid to upper 60s. Lows Tuesday night may also be impacted and given the potential for increasing clouds from the west towards daybreak will favor lows several degrees warmer than what the latest guidance suggests across far western Kansas. On Thursday a cold front will move into northern Kansas as an upper level disturbance drops south of of Canada and crosses the northern Plains. Timing issues exist on when this boundary will move into western Kansas. Given these timing issues with the frontal passage will stay close to the latest CRExtendFcst_Init on Temperatures Thursday and Friday. In addition to some cooler air returning to portions of northern Kansas behind the cold front late week there will also be improving chances for precipitation, especially across northern central Kansas. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 608 AM CDT MON MAY 12 2014 Model soundings indicating the depth of the low level moisture will decrease today as a surface ridge axis begins to build into western Kansas. Model soundings suggesting ceilings will improve to MVFR by 14z and VFR after 18z. HRRR also suggesting this trend as well. Gusty northwest winds of 20 to near 25 knots can be expected through at 00z Tuesday based on the mean mixed layer winds. After sunset winds will decrease to around 10 knots. && .PRELIMINARY POINT TEMPS/POPS... DDC 55 35 63 36 / 10 0 0 0 GCK 52 34 61 34 / 20 0 0 0 EHA 53 34 58 36 / 10 0 10 0 LBL 55 34 64 33 / 10 0 10 0 HYS 52 35 63 36 / 30 0 0 0 P28 62 40 65 39 / 20 0 10 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JJohnson LONG TERM...Burgert AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 515 AM EDT MON MAY 12 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A BUILDING RIDGE ALONG THE W COAST OF NAMERICA WITH AMPLIFIED DOWNSTREAM TROF OVER THE ROCKIES. MAIN PIECE OF ENERGY IS IN THE BASE OF THE TROF OVER COLORADO. WAA/ISENTROPIC ASCENT DOWNSTREAM INTO THE UPPER LAKES IS SUPPORTING A LARGE AREA OF SHRA/TSRA LIFTING NE ACROSS MN/WI EARLY THIS MORNING. SHORTWAVE MOVING NE INTO WRN WI IS FURTHER AIDING THE PCPN. INSTABILITY HAS BEEN SLOW TO ADVANCE N PER SPC MESOANALYIS...SO WHILE SHRA ARE ADVANCING STEADILY N AND E...TSRA ARE LAGGING FARTHER AND FARTHER S WITHIN THE OVERALL SHRA AREA. HIGH RES MODEL GUIDANCE...PARTICULARLY THE HIGH RES RAPID REFRESH... HAS A DECENT HANDLE ON APPROACHING SHRA. UTILIZED RADAR TRENDS AND HIGH RES GUIDANCE TO SWING A PERIOD OF CATEGORICAL POPS ACROSS THE FCST AREA THIS MORNING. FORTUNATELY...PCPN AMOUNTS DON`T LOOK TO BE EXCESSIVE AS MAIN AREA OF TSRA WILL PASS BY TO THE S. STILL... EXPECT ROUGHLY 0.5 TO 0.75 INCHES WHICH WILL GIVE AREA RIVERS/STREAMS A BOOST IN FLOW. AS SUPPORTING SHORTWAVE MOVES NE OF THE AREA...MUCH OF THE AFTN MAY TURN DRY IN ITS WAKE. POPS WERE LOWERED INTO THE CHC/SCT CATEGORY...BUT BELIEVE MANY AREAS WILL PROBABLY SEE A GOOD PERIOD OF DRY WEATHER THIS AFTN. WITH PCPN AT A MINIMUM DURING THE AFTN...TEMPS WILL HAVE A CHANCE TO RESPOND...AT LEAST IN AREAS WHERE GENERAL EASTERLY FLOW IS NOT OFF THE GREAT LAKES. BUMPED TEMPS UP INTO THE UPPER 50S/LWR 60S ACROSS MUCH OF THE INTERIOR. HIGH RES RAPID REFRESH SHOWS TEMPS RISING TO AROUND 70F OVER THE INTERIOR W THIS AFTN...CERTAINLY POSSIBLE IF CLOUDS THIN OUT SUFFICIENTLY. AS SFC LOW PRES LIFTS FROM WRN WI ACROSS WRN LAKE SUPERIOR TONIGHT...WARM FRONT WILL ATTEMPT TO MOVE INTO UPPER MI. AT THIS POINT...IT APPEARS THE WARM FRONT MAY JUST SLIP INTO FAR SRN UPPER MI. ADDITIONAL SHRA/TSRA WILL LIKELY DEVELOP AS SFC LOW/WARM FRONT LIFT N...THOUGH PCPN COVERAGE PROBABLY WON`T BE AS WIDESPREAD AS WHAT WILL OCCUR THIS MORNING. WITH ELEVATED CAPE UP AROUND 1000J/KG AND DEEP LAYER SHEAR AROUND 30KT OR SO...STORMS WILL HAVE THE POTENTIAL TO BECOME ORGANIZED WITH ISOLD SVR POSSIBLE...MAINLY OVER FAR SCNTRL UPPER MI...CLOSER TO WARM FRONT. MAIN THREAT SHOULD BE HAIL...BUT WITH PRECIPITABLE WATER 200-250PCT OF NORMAL...HVY RAINFALL WILL BE A GOOD BET WITH ANY TSRA. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 504 AM EDT MON MAY 12 2014 DEEP TROUGH FOR MAY AND REALLY ANYTIME OF THE YEAR STRETCHES FROM CENTRAL CANADA TO THE SOUTHERN PLAINS ON TUESDAY. SFC LOW CURRENTLY OVER THE CENTRAL PLAINS SHOULD BE JUST NORTHWEST OF LK SUPERIOR DAYBREAK ON TUESDAY. OCCLUDED FRONT WILL BE SLICING ACROSS CWA THROUGH MID MORNING...EXITING EASTERN CWA BY EARLY AFTN. SHOULD BE AT LEAST SCT SHRA/TSRA EXPECTED ALONG AND AHEAD OF FRONT AS HIGHER 1000-850MB THETA-E POOLS ALONG THE BOUNDARY. SHARP DRYING ENDS ANY RAIN QUICKLY OVER WEST HALF IN THE MORNING...BUT MAY SEE ISOLD SHRA/TSRA OVER FAR SOUTHEAST CWA AS WEAK LOW-LEVEL CONVERGENCE LINGERS AND AS ANOTHER WEAKER SHORTWAVE/Q-VECTOR CONVERGENCE AT H85-H5 LIFTS OVER FAR EAST CWA. ANY STORMS AHAEAD OF FRONT IN THE MORNING SHOULD BE WEAK AS 1-6KM MUCAPE AND MLCAPE BOTH DIMINISH STEADILY COMPARED TO THE OVERNIGHT HOURS. TEMPS WILL RISE INTO THE 60S OVER THE CNTRL WHERE WEST WINDS DOWNSLOPE...IMT-ESC-MNM...BUT WILL STAY IN THE 50S OVER THE WESTERN/NORTHWEST CWA WITH GRADIENT WINDS OFF LK SUPERIOR. THOSE WINDS COULD BE QUITE GUSTY...ESPECIALLY OVER THE MORE EXPOSED KEWEENAW...WHERE NAM/GFS SOUNDINGS INDICATE MIXED LAYER BUILDING TO H85-H8 WITH WINDS OVER 35 KTS IN THE MIXED LAYER. QUIET WEATHER TUESDAY NIGHT AND WEDNESDAY AS DEEP SFC LOW SLOWLY LIFTS TO JAMES BAY/HUDSON BAY. GRADIENT WEST FLOW STAYS OVER UPR MICHIGAN...BUT WILL LIGHTEN ENOUGH ON WEDNESDAY TO RESULT IN LAKE BREEZES. SLIM CHANCE THAT RESULTING LOW-LEVEL CONVERGENCE ADDED TO WEAK H7-H5 FORCING FM SHORTWAVE DROPPING ACROSS ON PERIFERY OF DEEP TROUGH ALOFT COULD TRIGGER A FEW SHOWERS/SPRINKLES INTERIOR CENTRAL. DEEP MIXING TO H8 WILL LIMIT POTENTIAL THOUGH AS LOW-LEVEL RH VALUES DROP OFF BLO 40 PCT. MAX TEMPS SHOULD PUSH INTO THE 50S INLAND AND FALL BACK INTO THE 40S NEAR LK SUPERIOR ONCE LAKE BREEZE DEVELOPS. THE FORECAST FOR THURSDAY INTO FRIDAY REMAINS UNCERTAIN. AT THE LEAST...TEMPS WILL BE BLO NORMAL FOR MOST CWA...PERHAPS BY MORE THAN 10-15F OVER THE NORTHERN CWA. ECMWF STILL SUPPORTS POTENTIAL FOR ACCUMULATING SNOW...NOW MAINLY DELAYED UNTIL THURSDAY NIGHT THROUGH FRIDAY AND POSSIBLY INTO FRIDAY NIGHT. LATEST UKMET ALSO IN LINE WITH THE ECMWF IDEA. MEANWHILE...GFS AND GEM-NH STAY WITH PROGRESSIVE IDEA INDICATING STRONG SHORTWAVE ROUNDING BASE OF DEEP TROUGH STAYS SEPARATE ENOUGH FROM TROUGH FROM HUDSON BAY TO THE NORTHERN PLAINS TO LIMIT PHASING. IF GFS THEME IDEA IS RIGHT...WOULD SEE SETUP WITH MORE DIURNALLY DRIVEN MAINLY RAIN SHOWERS DUE TO INSTABILITY ALOFT BENEATH THE TROUGH AXIS. IF THE ECMWF AND UKMET ARE ON THE RIGHT TRACK...THEY INDICATE ENOUGH PHASING BTWN THE LARGE SCALE TROUGHS TO DRAG A SFC LOW PRESSURE SYSTEM NORTHWARD OVER THE CNTRL GREAT LAKES INTO TOWARD THE UPPER GREAT LAKES THURSDAY INTO FRIDAY. WITH THAT SCNEARIO...WIDESPREAD RAIN AND SNOW THURSDAY EVENING WOULD CHANGE TO SNOW THURSDAY NIGHT INTO MUCH OF FRIDAY AND NORTHERLY FLOW WOULD ONLY BOOST THE SNOW OVER HIGHER TERRAIN AREAS NEAR LK SUPERIOR. SNOW COULD BE PRETTY WIDESRPEAD AS PYTPE WITH H85 TEMPS DROPPING BLO -5C AND SINCE 1000-850MB THICKNESSES FALL BLO 1300M. PHASING SYSTEMS ARE ALWAYS TOUGH TO FORECAST. ADD TO THAT FACT THAT WE ARE PUSHING INTO MIDDLE OF MAY AND IT MAKES IT REALLY TOUGH TO SAY IF UKMET AND ECMWF SOLUTION WILL WORK OUT AS FORECAST. SINCE ECMWF ENSEMBLE MEAN WOULD ALSO SUPPORT SIMILAR IDEA AND SOME CANADIAN ENSEMBLES HAVE SHOWN THIS RECENTLY IT DOES SUGGEST THE IDEA AT LEAST HAS SOME MERIT COMPARED TO JUST ONE ROUGE OPERATIONAL MODEL RUN SHOWING A BIG STORM IN THE FAR REACHES OF THE EXTENDED. ONCE THE SYSTEM OR JUST THE OPEN TROUGH MOVES BY...WEEKEND LOOKS DRIER WITH GRADUAL WARMING TREND. DID NOT STRAY FROM CONSENSUS LOW CHANCE POPS FOR NEXT WEEKEND ATTM. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 738 AM EDT MON MAY 12 2014 CHALLENGING FCST SHAPING OVER THE NEXT 24HRS AS LOW PRES AND WARM FRONT LIFT INTO THE UPPER GREAT LAKES. ONGOING SHRA WILL WORK TO MOISTEN THE LOW-LEVELS...AND EXPECT KIWD/KCMX/KSAW TO FALL TO MVFR THIS MORNING WITH SOME PERIODS OF IFR POSSIBLE. AS DISTURBANCE GENERATING THE MORNING SHRA EXITS TO THE NE...THERE MAY NOT BE ANY SHRA AT THE TERMINALS DURING THE AFTN HRS. WITH E UPSLOPE FLOW OFF CHILLY LAKE SUPERIOR...KCMX WILL PROBABLY SEE LIFR CONDITIONS DEVELOP. MAINTAINED MVFR CONDITIONS AT KIWD/KSAW. WITH MORE OF A DOWNSLOPE COMPONENT AT KIWD...EXPECT HIGHER CIGS THERE...AND ITS POSSIBLE THERE COULD BE SOME PERIODS OF VFR. ON THE OTHER HAND...UPSLOPE WIND AT KSAW COULD LEAD TO SOME PERIODS OF IFR. SHRA WILL REDEVELOP TONIGHT WITH LIFR/IFR CONDITIONS PREVAILING. COULD BE SOME TSRA AS WELL...PARTICULARLY AROUND KSAW...BUT LIMITED CONFIDENCE IN TIMING/COVERAGE OF TSRA PRECLUDES A MENTION IN THIS FCST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 504 AM EDT MON MAY 12 2014 EXPECT PERIOD OF STRONGER WINDS OVER LAKE SUPERIOR. APPROACHING LOW PRESSURE SYSTEM RESULTS IN NORTHEAST WINDS INCREASING TO GALES BY AFTN OVER WEST HALF OF LK SUPERIOR. WINDS TO 30 KTS OVER REST OF LK SUPERIOR. STRONG WINDS DIMINISH BRIEFLY LATER THIS EVENING AND OVERNIGHT TONIGHT AS THE LOW SLIDES ACROSS WESTERN LK SUPERIOR. ONCE THE LOW MOVES NORTH OF THE LAKE ON TUESDAY MORNING...STRONG WEST WINDS KICK UP. EXPECT THESE STRONG WESTERLIES...PROBABLY REACHING GALES ON TUESDAY OVER NCNTRL LK SUPERIOR...TO SLOWLY FADE BLO 25 KTS BY WEDNESDAY MORNING. WINDS REST OF THE WEEK WILL MAINLY BE BLO 20 KTS. HOWEVER...A LOW PRESSURE SYSTEM COULD IMPACT THE REGION LATE THIS WEEK WITH WINDS OVER 25 KTS THURSDAY INTO FRIDAY. UNCERTAINTY IS HIGH WITH THAT SYSTEM THOUGH...SO CURRENT FORECAST WILL ONLY CALL FOR NORTHWEST TO 20 KTS AT THIS TIME. && .HYDROLOGY... ISSUED AT 504 AM EDT MON MAY 12 2014 WIDESRPEAD MODERATE TO HEAVY RAIN WILL AFFECT ALL OF UPR MICHIGAN THROUGH EARLY THIS AFTN BEFORE DIMINISHING...THEN THERE MAY BE ANOTHER PERIOD OF MODERATE RAINFALL TONIGHT. RAINFALL AMOUNTS MAY EXCEED ONE INCH TODAY OVER PORTIONS OF WESTERN UPR MICHIGAN. RAIN CHANCES DIMINISH FROM WEST TO EAST ON TUESDAY AS A FRONTAL BOUNDARY EXITS THE REGION. RAINFALL WILL ONLY ADD TO THE ONGOING SNOWMELT AND ALREADY HIGH FLOWS ON AREA RIVERS AND STREAMS. THE PRIMARY CHANGE TO ONGOING HEADLINES WAS LAST EVENING...WHEN BASED ON EXPECTED RAINFALL...WHICH LOOKS LIKE IT IS WORKING OUT...ADVISORIES WERE UPGRADED TO WARNINGS FOR THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. THE WARNING FOR THE STURGEON RIVER NEAR CHASSELL AND THE ADVISORY FOR THE STURGEON RIVER NEAR ALSTON CONTINUE...AS DOES THE ADVISORY FOR THE MICHIGAMME RIVER DOWNSTREAM OF WAY DAM...TO THE EAST OF CRYSTAL FALLS IN IRON COUNTY. GIVEN THE RAINFALL THAT WILL AFFECT THE AREA THE NEXT 24-36 HOURS...RIVER LEVELS WILL KEEP RISING AND ADJUSTMENTS WILL LIKELY BE NEEDED BASED ON LATEST TRENDS. ALL THIS WATER DUE TO THE SNOWMELT AND THE RAINFALL WILL TAKE A WHILE TO WORK THROUGH THE RIVERS...SO IT IS QUITE LIKELY THAT HIGHER RIVER FLOWS AND THE ASSOCIATED ADVISORIES AND WARNINGS ON AREA RIVERS WILL CONTINUE THROUGH LATE THIS WEEK...IF NOT INTO NEXT WEEKEND. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA HYDROLOGY...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
706 AM CDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 334 AM CDT MON MAY 12 2014 SHOWERS ARE PUSHING EAST OF OUR WEST CENTRAL WI COUNTIES EARLY THIS MORNING WITH JUST A FEW SCATTERED SHOWERS ACROSS THE MN COUNTIES. RAINFALL AMOUNTS OVERNIGHT FROM 1 TO 1.50 INCHES HAVE BEEN COMMON ACROSS SOUTHERN MN AND ADJOINING AREAS OF WEST CENTRAL WI. RAINFALL AMOUNTS DROP OFF TO AROUND A HALF INCH FROM WEST CENTRAL MN TO NW WI. THE DAY AHEAD WILL FEATURE A LOW PRESSURE SYSTEM MOVING SLOWLY NORTHEAST FROM IA TO THE SOUTHERN TWIN CITIES METRO BY EARLY THIS AFTERNOON. THE LOW SHOULD REACH FAR NORTHERN WI BY LATE THIS EVENING. THERE IS PLENTY OF POTENTIAL FOR SEVERE STORMS TO DEVELOP THIS AFTERNOON/EVENING IN THE VICINITY OF THE SURFACE LOW AND WARM FRONT EXTENDING TO THE EAST. LIMITING FACTORS WILL BE THE EXTENSIVE CLOUDINESS THAT WILL HOLD DOWN ON THE DESTABILIZATION. RAP DATA SHOWS A WARM POCKET MOVING NORTHEAST FROM IA THIS MORNING BETWEEN 650-700MB. THIS IS SQUARELY OVER WEST CENTRAL WI EARLY THIS AFTERNOON. LOW LEVEL LAPSE RATES SUFFER AS WELL AS SURFACE BASED CAPE. HOWEVER...BY LATE IN THE AFTERNOON...SOUNDING DATA FOR KEAU SHOWS THE POTENTIAL TO WARM ENOUGH TO GET PAST THE MID LEVEL WARM POCKET. SURFACE BASED CAPE REACHES A LITTLE MORE THAN 2000 J/KG. SHEAR IS ADEQUATE WITH 0-1KM REACHING 25 KNOTS WITH 0-6KM BETTER THAN 45 KNOTS. 500MB WINDS ARE VERY IMPRESSIVE WITH A CORE OF 60-70 KNOT WINDS PROGGED ACROSS THE TWIN CITIES AND WEST CENTRAL WI THIS AFTERNOON. OUR MPXWRF...THE HOPWRF AND THE SPCWRF START BREWING TROUBLE ALONG OUR MN/WI BORDER AREA BY 21Z WITH THE HINT OF A FEW SUPERCELLS ACROSS WEST CENTRAL WI INTO THE EARLY EVENING. GIVEN THE LOW LCLS...SHEAR AND WARM FRONT...A TORNADO OR TWO CAN NOT BE RULED OUT. IN FACT...THERE HAVE BEEN TORNADOES THE PAST TWO DAYS NEAR THE SURFACE LOW AND WARM FRONT. NORTHWEST WINDS WILL STRENGTHEN ACROSS THE FA TONIGHT IN THE WAKE OF THE LOW PRESSURE SYSTEM. THIS WILL USHER IN MUCH COOLER AIR THAT WILL BE WITH US FOR THE BALANCE OF THE WEEK AS A LARGE TROUGH ALOFT DOMINATES ACROSS THE MISSISSIPPI VALLEY REGION. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 334 AM CDT MON MAY 12 2014 THE THEME FOR THE LONG TERM PERIOD IS DRY WEATHER FOR THE UPPER MIDWEST. ALTHOUGH...IT WILL ALSO BE A COOL PERIOD MAINLY TUESDAY THROUGH FRIDAY AS TEMPERATURES WILL RUN 10 TO 15 DEGREES BELOW NORMAL. PICKING UP TUESDAY MORNING...THE UPPER LEVEL TROUGH AXIS WILL BE IN THE VICINITY OF THE WESTERN MN/EASTERN DAKOTAS BORDER. THE SURFACE LOW WILL HAVE LIFTED UP INTO ONTARIO NORTH OF LAKE SUPERIOR. THE NAM REMAINS STUBBORN IN HAVING THE MOVEMENT OF THE LOW A TAD SLOWER/GIVEN ITS DEEPER SOLUTION WITH THE TROUGH MONDAY NIGHT/...BUT IT HAS STARTED TO MOVE TOWARD THE GFS/EC SOLUTIONS. PREFERRED A EC/GFS BLEND THAT HAS THE LOW QUICKLY MOVING NORTH. THE UPPER TROUGH AND MOISTURE ON THE BACK SIDE OF THE LOW WARRANTED THE MENTION OF POPS ACROSS THE NORTHERN PART OF THE FA...BUT ANY PRECIPITATION WILL BE VERY LIGHT. WITH THE UPPER TROUGH OVERHEAD...TEMPERATURES WILL BE HELD IN THE 50S DURING THE DAY...AND WITH THE DEPARTING LOW NORTHWEST WINDS WILL BE BLUSTERY AND MAKE FOR A COOL DAY. WINDS SHOULD SLACKEN AND SKY COVER BEGIN TO BREAK UP TUESDAY EVENING. 850H TEMPS WILL FALL BELOW ZERO OVERNIGHT AND GIVEN WEAKENING WINDS AND AND DIMINISHING SKY COVER OVERNIGHT...TEMPERATURES BY EARLY WEDNESDAY MORNING WILL BE IN THE 30S ACROSS THE FA. LITTLE CHANGE IS EXPECTED WEDNESDAY AS THE AMPLIFIED UPPER TROUGH AND CORE OF THE COOL AIR REMAINS OVERHEAD. MEANWHILE...BOTH THE EAST COAST AND WEST COAST WILL HAVE HIGHLY AMPLIFIED RIDGING AND WARM TEMPERATURES. SLIGHT CHANCE POPS DO SHOW UP AGAIN WEDNESDAY AFTERNOON ACROSS THE WEST AS ADDITIONAL MOISTURE ALOFT ROTATES SOUTH ON THE BACK SIDE OF THE UPPER TROUGH. WOULD NOT BE SURPRISED IF LOW LEVEL DRY AIR PREVENTS ANYTHING FROM REACHING THE GROUND. WEDNESDAY NIGHT WILL BE COLDER AS 850H TEMPS DROP TO -2C TO -6C GENERALLY ACROSS THE FA. WIDESPREAD 30S ARE EXPECTED WITH SOME SPOTS HITTING THE FREEZING MARK. THE AMPLIFIED TROUGH WILL PUSH SLIGHTLY EAST AND BECOME A CLOSED UPPER LOW OVER WISCONSIN THURSDAY NIGHT INTO FRIDAY SO CYCLONICALLY CURVED FLOW MAY AGAIN PRODUCE VERY LIGHT PRECIP THURSDAY AFTERNOON. THE POPS ASSOCIATED WITH THIS TROUGH DURING THE MIDWEEK MAY BE OVERDONE BY THE LARGE SCALE SYNOPTIC MODELS...HOWEVER...SO WHILE THERE ARE SOME POPS IN THE FORECAST FOR THE MIDWEEK TIME FRAME...TOTAL AMOUNTS WILL BE UNDER A TENTH OF AN INCH...AND WILL LIKELY BE ZERO FOR PARTS OF THE AREA. WE`LL SEE THE CORE OF THE COOL AIR ALOFT PUSH EAST AT THE START OF THE WEEKEND AS THE WESTERN CONUS RIDGE STARTS PUSHING INTO THE CENTER OF THE COUNTRY BY SUNDAY. BESIDES A COOL START...THE WEEKEND LOOKS DRY...PARTLY CLOUDY...AND WARMER THAN THE COLD MIDWEEK AHEAD. BEYOND THE WEEKEND...THE RIDGE AXIS WILL PUSH OVER OUR AREA EARLY NEXT WEEK AND TEMPERATURES WILL CONTINUE TO WARM. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 706 AM CDT MON MAY 12 2014 SURFACE LOW PRESSURE OVER FAR SOUTH CENTRAL MN WILL BE MOVING SLOWLY NORTHEAST TODAY...REACHING THE TWIN CITIES BY EARLY THIS AFTERNOON AND NORTHERN WI BY LATE THIS EVENING. IFR CEILINGS AND MVFR VSBYS IN -RA/DZ/BR ARE WIDESPREAD ON THE COLD SIDE OF THE LOW (KRWF/KSTC/KAXN). THESE SITES SHOULD STAY THIS WAY THROUGH THE DAY WITH ONLY A LITTLE IMPROVEMENT OVERNIGHT. CONFIDENCE IS LOWER FOR KMSP...KRNH AND KEAU WHERE MAINLY VFR CEILINGS EXISTS. HOWEVER...DUE TO THE HIGHS DEW POINTS AND NEAR SATURATION IN THE LOW LEVELS...MVFR OR LOWER CIGS SHOULD DEVELOP THIS MORNING AND PERSIST THROUGH THE AFTERNOON AND THEN LOWER TO IFR TONIGHT ON THE BACKSIDE OF THE LOW. SOME SHOWERS WILL MOVE THROUGH THIS MORNING WITH THE THREAT FOR THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING. CONFIDENCE IS HIGHEST FOR THUNDER AT KEAU DURING THE LATE AFTERNOON HOURS. SOUTHEAST WINDS AHEAD OF THE LOW ON THE WARM SIDE WITH NORTH TO NORTHWEST WINDS 10-15 KNOTS ON THE COLD SIDE. KMSP...LOW CONFIDENCE FORECAST ON MVFR CEILINGS THIS MORNING. ERRED ON THE LOW SIDE VERSUS VFR BEING OBSERVED FROM THE AIRFIELD ON SOUTH AND EAST. FIGURING A LITTLE HEATING THIS MORNING WITH THE SATURATED CONDITIONS WILL RESULT IN LOW CEILINGS DEVELOPING QUICKLY. CERTAINLY THIS AFTERNOON AS WE TRANSITION TO THE BACKSIDE OF THE APPROACHING LOW PRESSURE SYSTEM CEILINGS WILL DROP TO IFR AND STAY THERE THROUGH MUCH OF TONIGHT. SHOWER/TSRA CHANCES ARE BEST TO THE EAST AND SOUTH OF THE AIRFIELD TODAY WITH -RA/DZ MORE LIKELY LATER THIS AFTERNOON AND TONIGHT. WINDS HAVE DIMINISHED SINCE TAF ISSUANCE WITH LIGHT WINDS FOR THE NEXT FEW HOURS. THE WINDS SHOULD PICK UP LATER IN THE MORNING FROM THE NE AND THEN BECOME NW THIS AFTERNOON. /OUTLOOK FOR KMSP/ TUE...MVFR LIKELY. SLGT CHC -SHRA. WINDS W-NW 15-20 KTS. WED...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS W-NW 10-15 KTS. THU...MVFR POSSIBLE. SLGT CHC -SHRA. WINDS NW 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...RAH LONG TERM...SPD AVIATION...RAH
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
650 AM CDT Mon May 12 2014 .SHORT TERM: (Today and Tonight) Issued at 330 AM CDT Mon May 12 2014 Main forecast issues for today are the probability of thunderstorms and any severe potental, as well as just how warm it may get. Current thinking is there should be a gradual upswing in convection as the day progresses, primarily during the later half of the afternoon. It appears that northeast Missouri will be the area we will have to watch most closely through mid morning. Two things to key an eye on - an outflow boundary pushing southeastward across eastern Iowa as a focus for additional thunderstorms, and also a cluster of thunderstorms across eastern Kansas just southwest of Kansas City and if they will hold together as they move northeastward. Otherwise I think that there will be a general decrease in the convective cloud debris during the morning, which given the mild early morning temperatures should allow for a quick warm-up by early afternoon. The convection allowing models and more specifically the HRRR is suggesting that by mid morning, isolated showers or thunderstorms could develop just about anywhere within the CWA, but most favored across southeast Missouri and southern Illinois. The main action still looks like the later half of the afternoon. The warm sector air mass ahead of the cold front will become quite unstable by mid-late afternoon with SBCAPE in excess of 2000 J/KG and little CIN. Expecting numerous thunderstorms to develop across western Missouri into central and northeast Missouri. Deep layer shear of 20-30 kts and the anticipated CAPE would support a few severe storms capable of large hail and damaging winds from the afternoon into about mid-evening. The front moves through all but the far eastern sections of the CWA tonight accompanied by widespread showers and thunderstorms and ushering much cooler air into the region in its wake. It also appears that there will be an increasing amount of post-frontal showers overnight immediately in the cool air in response to large scale forcing. Glass .LONG TERM: (Tuesday through Sunday) Issued at 330 AM CDT Mon May 12 2014 This marks the beginning of a cooler than normal period with a slow-moving and deep upper trof dominating the region through the week. The front will quickly exit the remainder of the CWA early Tuesday morning with post-frontal showers impacting eastern Missouri and southwest Illinois in the morning and exiting by early-mid afternoon. Highs on Tuesday will be around 20 degrees cooler than today. A strong short-wave and possibly upper low will then migrate through the base of the deep trof from the southern Plains and into the mid MS valley Tuesday night-Wednesday night. More reminiscent of Fall or early Spring, large scale ascent with this system should produce a large area of showers or rain spreading into the area late Tuesday night into Wednesday. Its northward extent and longevity is all dependent on the strength of the system, and NAM featuring a closed low and large deformation zone, has the greatest northward push and keeps precipitation well into Wednesday night. Regardless the precipitation and accompanying overcast low clouds will keep temperatures well below average on Wednesday. We could continue to see a periodic shower threat through the end of the week as we get into deeper cyclonic flow on the backside of the slow-moving deep upper trof. Temperatures will remain below average into at least Friday. Glass && .AVIATION: (For the 12z TAFs through 12z Tuesday Morning) Issued at 640 AM CDT Mon May 12 2014 Mvfr strato cu deck advecting northward in warm sector and will remain over region through mid morning before scattering out. Otherwise, main issue is the chance for showers and thunderstorms as cold front moves through region late this afternoon and tonight. Activity will be scattered ahead of boundary so added vcnty ts mention after 15z with tempo of thunderstorms later this afternoon, mainly after 21z. Once front moves through will still see some lingering showers through rest of forecast period. As for winds, to remain from the south and pickup with gusts to near 25kts at times today. Then veer to the west as front moves through and become northwesterly later tonight. Specifics for KSTL: Mvfr strato cu deck advecting northward in warm sector and will remain over region through mid morning before scattering out. Otherwise, main issue is the chance for showers and thunderstorms as cold front moves through region late this afternoon and tonight. Thunderstorms to develop and move in later this afternoon, mainly after 00z Tuesday. Once front moves through will still see some lingering showers through rest of forecast period. As for winds, to remain from the south and pickup with gusts to near 25kts at times today. Then veer to the west by 04z Tuesday as front moves through and become northwesterly after 09z Tuesday. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CDT MON MAY 12 2014 .UPDATE... ISSUED AT 1005 AM CDT MON MAY 12 2014 MADE SOME SLIGHT ADJUSTMENTS TO BUMP UP SKY COVER A LITTLE IN THE WEST THROUGH THIS MORNING. ALSO ADJUSTED PRECIPITATION BASED ON LATEST RADAR AND 12Z HRRR GUIDANCE. OTHERWISE NO SIGNIFICANT CHANGES TO THE GOING FORECAST. UPDATE ISSUED AT 639 AM CDT MON MAY 12 2014 NO MAJOR UPDATES ARE REQUIRED TO THE ONGOING FORECAST. THE CURRENT WIND ADVISORY STILL LOOKS GOOD FOR TODAY. ONLY MODIFIED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 353 AM CDT MON MAY 12 2014 MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE PRECIPITATION CHANCES OVER THE EASTERN THIRD OF THE FORECAST AREA TODAY...AND WINDS TODAY. CURRENTLY...FRONTAL BOUNDARY EXTENDED FROM LAKE WINNIPEG SOUTHEAST ACROSS MINNESOTA SOUTH INTO IOWA AND SOUTHWESTWARD TO KANSAS AND OKLAHOMA. HIGH PRESSURE EXTENDED ALONG THE FRONT RANGE OF THE ROCKIES. WIDESPREAD LOWER CLOUD COVER ACROSS EASTERN PORTIONS OF CENTRAL NORTH DAKOTA...WITH HIGHER CLOUDS TO THE WEST. AT UPPER LEVELS...A LARGE LONGWAVE TROUGH EXTENDED FROM NORTH CENTRAL CANADA SOUTHWARD ACROSS THE DAKOTAS TO THE 4-CORNERS AREA. MODELS ARE IN GOOD AGREEMENT KEEPING AN AREA OF SHOWERS MAINLY FROM SOUTH CENTRAL NORTH DAKOTA EAST OF THE MISSOURI RIVER TO THE JAMES AND DEVILS LAKE BASINS...MAINLY SOUTH AND EAST OF A LINE FROM LINTON TO HARVEY AND CARRINGTON. THERE MAY BE A RAIN/SNOW MIX ON THE FAR WESTERN EDGE OF THE PRECIPITATION - BUT WOULD BE VERY LIGHT. TEMPERATURES WEST OF THE PRECIPITATION AREA WERE IN THE LOWER 30S...WITH UPPER 30S TO 40 WHERE SCATTERED SHOWERS WERE OCCURRING. THE UPPER LEVEL TROUGH IS PROGGED TO MOVE EASTWARD SLOWLY TODAY - REACHING MINNESOTA BY DAYBREAK TUESDAY MORNING. MEANWHILE THE SURFACE FRONTAL BOUNDARY EVOLVES INTO A CLOSED LOW OVER WISCONSIN BY THIS EVENING...LIFTING NORTHWARD ACROSS LAKE SUPERIOR INTO WESTERN ONTARIO BY DAYBREAK TUESDAY. THIS WILL KEEP THE EASTERN THIRD OF NORTH DAKOTA WITHIN THE WESTERN BOUNDARY OF THE EXPECTED AREA OF SHOWERS TODAY THROUGH THIS EVENING...WITH CHANCES OF PRECIPITATION DECREASING DURING THE OVERNIGHT HOURS MONDAY NIGHT. THE WEST WILL CONTINUE TO DRY OUT AS HIGH PRESSURE CONTINUES TO MOVE SOUTH/SOUTHEAST INTO THE WESTERN PLAINS. THE PRESSURE GRADIENT BETWEEN THE STRONG LOW AND HIGH PRESSURE SYSTEMS WILL SET UP FOR WINDY CONDITIONS TODAY - AND THE CURRENT WIND ADVISORY FOR ALL BUT THE FAR NORTHWEST SEEMS REASONABLE AND WILL NOT CHANGE AREAL COVERAGE OR TIMING OF THE WIND ADVISORY. BUFR SOUNDINGS STILL INDICATE THAT BY AROUND 9-10 AM SHOULD SEE MIXING OF BOUNDARY LAYER WINDS...RESULTING IN AN AREA OF SUSTAINED 30 MPH WINDS WITH GUSTS TO 40 MPH AT TIMES. USED A CONSENSUS BLEND OF MODELS FOR WIND SPEEDS WHICH KEEPS THE ADVISORY CRITERIA ACROSS MOST OF THE CWA. WINDS SHOULD DECREASE FROM WEST TO EAST TONIGHT TO AROUND 10 TO 15 MPH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 353 AM CDT MON MAY 12 2014 THE 00Z GFS/GEM/ECMWF PROG AN UPPER LOW/WAVE TO CONTINUE TO MEANDER EAST INTO NORTHEASTERN MANITOBA/NORTHWESTERN ONTARIO TUESDAY. MOST OF THE MOISTURE/PRECIPITATION CHANCES OVER WESTERN AND CENTRAL NORTH DAKOTA WILL CONTINUE TO SHIFT EAST IN RESPONSE. BY WEDNESDAY AND THURSDAY...SYNOPTIC SUBSIDENCE IS PROGGED TO OVERSPREAD THE STATE LEADING TO DRY CONDITIONS. SURFACE HIGH PRESSURE IS PROGGED TO SETTLE ACROSS THE STATE THURSDAY MORNING. THIS COULD LEAD TO LOWS IN THE LOWER 30S/UPPER 20S THURSDAY MORNING...ESPECIALLY IN LOW-LYING AREAS. THE MEDIUM RANGE MODELS HAVE BACKED OFF ON A WEAK WAVE PREVIOUSLY FORECAST TO TRAVERSE NORTH DAKOTA FRIDAY/FRIDAY NIGHT. FOR THE SAKE OF CONSISTENCY...CONTINUED TO INDICATE SLIGHT CHANCE POPS FRIDAY/FRIDAY NIGHT. IF THE LATEST TRENDS CONTINUE...FUTURE SHIFTS MAY NEED TO REMOVE POPS FROM THE FRIDAY FORECAST ALTOGETHER. AN UPPER LEVEL RIDGE IS THEN FORECAST TO TRANSLATE EAST INTO THE GREAT PLAINS BY SATURDAY GENERATING DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. THE MEDIUM RANGE MODELS ARE SURPRISINGLY CONSISTENT PROGGING A PACIFIC NORTHWEST LONGWAVE TROUGH TO ENTER THE NORTHERN ROCKIES SUNDAY. THE POSITION OF THIS FEATURE WARRANTS A CHANCE OF SHOWERS MENTION FOR NOW...ESPECIALLY ACROSS WESTERN NORTH DAKOTA. COULD BEGIN TO SEE SOME THUNDER CHANCES SNEAK IN OVER WESTERN NORTH DAKOTA GIVEN THE FORECAST UPPER PATTERN SUNDAY. HOWEVER...WILL KEEP THUNDER OUT OF THE FORECAST FOR NOW DUE TO THE UNCERTAINTIES ASSOCIATED WITH A DAY 7 FORECAST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 1005 AM CDT MON MAY 12 2014 SCATTERED TO NUMEROUS SHOWERS EXPECTED AT KJMS WITH MVFR CEILINGS THE PREVAILING CONDITIONS. VFR CLOUDS WILL BE IN PLACE AT THE REMAINING TAF SITES. STRONG NORTH WINDS EXPECTED ACROSS MOST OF WESTERN AND CENTRAL NORTH DAKOTA TODAY. SUSTAINED WINDS AROUND 25 KTS AT KDID...KBIS...KMOT AND KJMS WITH GUSTS UP TO AROUND 35 KTS. WINDS WILL BE NOT AS STRONG AT KISN WITH SUSTAINED 15 T0 20 KNOTS AND GUSTS TO 30 KTS. WINDS TO SUBSIDE BY AROUND 00Z WEST TO 03Z EAST. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NDZ002>005-010>013-018>023-025-031>037-040>048-050-051. && $$ UPDATE...TWH SHORT TERM...JV LONG TERM...TM AVIATION...TWH
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1008 AM EDT MON MAY 12 2014 .DISCUSSION... AN UPPER-LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE ACROSS THE FORECAST AREA TODAY...AND HAS PROMOTED MOSTLY CLEAR CONDITIONS ACROSS THE TENNESSEE VALLEY THIS MORNING /EXCEPTION OF A FEW BANDS OF HIGH CLOUDS MOVING OVER THE NORTHERN PLATEAU AND CENTRAL VALLEY/. THE ABUNDANT SUNSHINE AND WARM TEMPERATURES ALOFT/HIGH THICKNESS VALUES WILL ALLOW FOR A QUICK WARM-UP INTO THE LOW 80S BY MIDDAY AND A EVENTUALLY INTO THE MID TO UPPER 80S ACROSS MUCH OF THE VALLEY AGAIN BY THE AFTERNOON /WITH A FEW SPOTS APPROACHING 90 DEGREES/. WITH MOISTURE UNDERNEATH THIS RIDGE HOWEVER...THE SOME DIURNALLY DRIVEN CONVECTION IS EXPECTED /PRIMARILY ALONG THE EAST TENNESSEE/WESTERN NORTH CAROLINA MOUNTAINS/ THIS AFTERNOON AND EVENING. MODELS ARE ALSO SHOWING SOME ADDITIONAL CONVECTION FIRING ACROSS SOUTHERN KENTUCKY AND MAKING ITS WAY ALONG THE NORTHERN PLATEAU AND SOUTHWEST VIRGINIA BY THE AFTERNOON. GIVEN THIS...HAVE LOW-END MENTIONABLE POPS IN THESE AREAS AND CHANCE POPS ALONG THE MOUNTAINS /AS THIS ACTIVITY SHOULD BE ISOLATED TO SCATTERED IN NATURE/. HOWEVER...KEPT MENTIONABLE POPS OUT OF THE VALLEY FOR NOW AS THINK MODELS ARE OVER DOING IT SOMEWHAT WITH THE CAP STILL IN PLACE. THIS THINKING IS SUPPORTED WELL BY THE HRRR WHICH SHOWS CONVECTION PRIMARILY ALONG THE MOUNTAINS AND LATE MOVING INTO SW VIRGINIA. THERE WILL BE ENOUGH INSTABILITY LATER TO SUPPORT SOME STRONG STORMS CAPABLE OF GUSTY WINDS AND SMALL HAIL ALONG THE MOUNTAINS...WITH THE POTENTIAL FOR A ROGUE SEVERE STORM OR TWO. HOWEVER...GIVEN THE LACK OF ORGANIZATION...AM NOT ANTICIPATING ANYTHING MORE THAN A VERY ISOLATED SEVERE THREAT FOR THOSE AFOREMENTIONED AREAS ATTM. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 88 65 87 64 / 10 10 30 40 KNOXVILLE MCGHEE TYSON AIRPORT, TN 87 63 86 63 / 10 10 30 30 OAK RIDGE, TN 87 63 85 63 / 10 10 30 40 TRI CITIES AIRPORT, TN 85 60 84 60 / 20 10 30 30 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ AMP
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1039 AM CDT MON MAY 12 2014 .UPDATE... CURRENT FORECAST IS IN GOOD SHAPE AND HAVE ONLY MADE SOME COSMETIC CHANGES TO THE HOURLY DATA AND MORNING POPS. LATEST SURFACE ANALYSIS INDICATES THAT THE COLD FRONT IS LOCATED ALONG A LINE ACROSS CENTRAL OKLAHOMA INTO NORTHWEST TEXAS BETWEEN BOWIE AND WICHITA FALLS SOUTHWARD TO BRECKENRIDGE. AHEAD OF THE COLD FRONT AN AREA OF SHOWERS AND THUNDERSTORMS INITIATED ON WHAT APPEARS TO BE AN INITIAL WAVE OF FORCING OR A SOUTHWARD PROPAGATING GRAVITY WAVE. EITHER WAY...AMDAR SOUNDING DATA FROM DFW AIRCRAFT INDICATE THAT STRONG CAPPING INVERSION NOTED ON 12Z FWD SOUNDING WAS ALL BUT COMPLETELY ERODED IN ABOUT 45 MINUTES. THIS INITIAL WAVE OF ACTIVITY HAS FAILED TO ORGANIZE OR REALLY TAKE OFF IN INTENSITY WHICH HAS LEFT THE LOW LEVEL WINDS AND MOISTURE IN PLACE BEHIND IT. THIS WILL LIKELY HELP TO INITIATE MORE ROBUST THUNDERSTORM ACTIVITY OVER THE NEXT FEW HOURS AS THE FRONT CONTINUES TO MOVE SOUTH. LATEST OBJECTIVE ANALYSIS ACROSS NORTH TEXAS SHOWS AROUND 2000 J/KG OF SURFACE BASED INSTABILITY SOUTH/EAST OF THE FRONT WHERE THE SUN HAS COME OUT A BIT WITH LITTLE INHIBITION LEFT. EXPECT THUNDERSTORMS TO BECOME MORE NUMEROUS IN COVERAGE THROUGH EARLY AFTERNOON. THE SEVERE THREAT REMAINS ACROSS NORTH TEXAS...ESPECIALLY GIVEN THE STRONG INSTABILITY...HOWEVER DEEP LAYER SHEAR ISNT ALL THAT STRONG SO MULTICELL CLUSTERS ARE EXPECTED. SOME SEVERE WIND GUSTS WOULD BE POSSIBLE ALONG WITH SEVERE HAIL. THE MORE SIGNIFICANT THREAT WILL BE FOR VERY HEAVY RAINFALL AND FLASH FLOODING...ESPECIALLY ACROSS THE EASTERN COUNTIES WHERE THE FRONT IS EXPECTED TO SLOWLY MOVE THROUGH TONIGHT. SOME AREAS COULD PICK UP IN EXCESS OF 3 INCHES OF RAIN IN A SHORT PERIOD OF TIME WITH ADDITIONAL RAINFALL PERSISTING INTO TONIGHT. DUNN && .AVIATION... CONCERNS...TIMING OF CONVECTION AND WIND SHIFT. ...WIDESPREAD DISRUPTIONS ARE EXPECTED THIS AFTERNOON AT DFW AIRPORT AND DALLAS LOVE FIELD... A COLD FRONT IS STEADILY APPROACHING FROM THE NORTHWEST. ALTHOUGH FRONTS TEND TO SLOW DOWN DURING THE DAYLIGHT HOURS...THE MOTION OF THE BOUNDARY TODAY WILL BE ENHANCED BY CONVECTION. SHOWERS AND THUNDERSTORMS HAVE ALREADY REDEVELOPED ALONG THE BOUNDARY DURING THE PREDAWN HOURS...AND ADDITIONAL ACTIVITY MAY DEVELOP WELL IN ADVANCE OF THE WIND SHIFT THIS MORNING. THIS ACTIVITY WILL PRIMARILY IMPACT NORTHWEST ARRIVALS THIS MORNING...BUT SOME SHOWERS OR STORMS COULD OCCUR NEAR METROPLEX AIRPORTS BEFORE MIDDAY. THE BULK OF THE THUNDERSTORM ACTIVITY IN THE IMMEDIATE METROPLEX WILL BE DURING THE AFTERNOON HOURS...WHEN A LINE OF STORMS MOVES SLOWLY THROUGH. WINDS MAY BE CHAOTIC WITH THE ACTIVITY...BUT NORTHWEST WINDS SHOULD PREVAIL BY MID-AFTERNOON. ALTHOUGH SOME STRONG OR MARGINALLY SEVERE STORMS WILL BE POSSIBLE WITHIN THE LINE...THE MAIN IMPACTS TO COMMERCIAL AVIATION TODAY WILL BE FROM LIGHTNING. SIMILAR IMPACTS ARE EXPECTED AT CENTRAL TEXAS AIRPORTS...BUT THE ACTIVITY AND WIND SHIFT WILL LIKELY OCCUR A FEW HOURS LATER THAN IN THE METROPLEX. THE FRONTAL PASSAGE WILL NOT BRING AN END TO THE PRECIPITATION... AND RAIN WILL CONTINUE MUCH OF THE EVENING. THE 850MB FRONT MAY BE AS MUCH AS 12 HOURS BEHIND THE SURFACE BOUNDARY...AND BUOYANT GULF AIR WILL MAINTAIN INSTABILITY ABOVE THE FRONTAL LAYER SUFFICIENT FOR THUNDER. HOWEVER...THE THUNDER THIS EVENING AND OVERNIGHT IS EXPECTED TO BE ISOLATED. TO REDUCE THE NUMBER OF HOURS WITH THUNDER IN THE TAFS...WILL CARRY PREVAILING RAIN WITHOUT THUNDER. 25 && .PREV DISCUSSION... /ISSUED 437 AM CDT MON MAY 12 2014/ THE POTENT UPPER LEVEL LOW OVER THE FOUR CORNERS THAT WAS RESPONSIBLE FOR SNOW IN DENVER YESTERDAY WILL EJECT NORTHEAST OUT INTO THE PLAINS TODAY...BUT ADDITIONAL UPPER ENERGY WILL DROP INTO THE BASE OF A DEEPENING LONGWAVE TROUGH TODAY. THIS UPPER TROUGH WILL ENGULF THE CENTRAL US BY TOMORROW...A PATTERN THAT IS VERY UNUSUAL FOR MID MAY. THIS SYSTEM HAS TAPPED INTO A CANADIAN AIRMASS AND HAS SENT AN UNSEASONABLY STRONG COLD FRONT BARRELING SOUTH. AT 4AM...THIS FRONT WAS LOCATED JUST SOUTH OF LUBBOCK TO NEAR VERNON TO EL RENO OKLAHOMA AND WAS MOVING SOUTHEAST AT 15 TO 20MPH. THE FRONT IS AHEAD OF MOST MODEL PROJECTIONS...WHICH IS NOT SURPRISING GIVEN THE COLD AIR BEHIND IT. THE RAP HAS A GOOD HANDLE ON THE FRONT/S SPEED AND IT WILL BE USED FOR TIMING. THE FRONT WILL ARRIVE INTO THE NORTHWEST CWA BY MID-MORNING AND CONTINUE TO TRACK SOUTHEAST...BUT SLOW DOWN A BIT DUE TO DAYTIME HEATING. THE FRONT SHOULD REACH A SHERMAN TO DFW TO COMANCHE LINE BY MID-AFTERNOON. THE AIRMASS AHEAD OF THE FRONT WILL BE WARM AND MOIST...WITH SEVERAL DAYS OF SOUTHERLY FLOW NOW BRINGING PRECIPITABLE WATER VALUES UP TO 1.75 TO 2 INCHES. SURFACE BASED CAPE WILL PEAK AROUND 2000-2500 J/KG THIS AFTERNOON AS TEMPS WARM INTO THE MID 80S. DAYTIME HEATING AND FORCING FOR ASCENT FROM THE UPPER LEVEL TROUGH WILL LIFT/ERODE THE WEAK CAPPING INVERSION...AND THUS CONVECTION WILL INCREASE IN COVERAGE ALONG THE FRONT BY LATE MORNING. BULK LAYER SHEAR IS FAIRLY WEAK...ON THE ORDER OF 25KT...SO MULTICELLULAR CONVECTIVE MODES ARE EXPECTED. GIVEN THE HIGH INSTABILITY AND WEAK SHEAR...SOME SEVERE WIND/HAIL REPORTS ARE POSSIBLE TODAY WITH THE STRONGEST STORMS. CONVECTION ALONG THE FRONT WILL LIKELY CONGEAL INTO A SOLID LINE OF THUNDERSTORMS BY MID-AFTERNOON...WITH THE LINE CONTINUING TO GROW UPSCALE INTO A FORMIDABLE LINEAR MCS BY THE EVENING HOURS. MCS PROPAGATION VECTORS AND DIFFLUENT THICKNESS FIELDS ALOFT SUGGEST THAT THE MOVEMENT OF THIS SYSTEM WILL REMAIN FAIRLY SLOW...LIKELY LESS THAN 10-15MPH. THIS FORWARD SPEED SHOULD IN THEORY LIMIT THE DAMAGING WIND THREAT THIS EVENING OVER THE SOUTHEAST HALF OF THE CWA...BUT WILL RESULT IN ENHANCED RAINFALL TOTALS. THE MCS WILL LIKELY HAVE SLOWER WEST TO EAST MOVEMENT THAN NORTH TO SOUTH...AND THUS THE ORIENTATION OF THE LINE SUGGESTS THAT EASTERN ZONES WILL HAVE A GREATER RISK FOR PROLONGED HEAVY RAINFALL. EXPECT THE LINE TO PUSH THROUGH THE SOUTHWEST ZONES FAIRLY QUICKLY...LIKELY REACHING A LAMPASAS TO WACO LINE BY 6 PM. A TIGHT RAINFALL GRADIENT IS FORECAST OVER THE CWA WITH LESS THAN A HALF INCH EXPECTED OVER THE NW ZONES...TO 1-2 INCHES IN A BAND FROM THE SHERMAN AREA TO THE METROPLEX TO COMANCHE...AND 2-3 INCHES SOUTH AND EAST OF A PARIS TO GREENVILLE TO HILLSBORO LINE. THIS LATTER REGION WAS THE SAME AREA THAT RECEIVED A SWATH OF 2-4 INCHES OF RAIN THURSDAY AND SOILS ARE ALREADY SATURATED. THUS A FLASH FLOOD WATCH WAS ISSUED FOR LOCATIONS ALONG AND SOUTHEAST OF A BONHAM TO DALLAS TO TEMPLE LINE. WHILE WE DONT EXPECT MOST OF DALLAS AND COLLIN COUNTIES TO RECEIVE MORE THAN 2 INCHES...GIVEN THE URBAN DEVELOPMENT THERE AND THE FACT THAT THE SOUTHEAST PARTS OF THESE COUNTIES DID SEE OVER 4 INCHES...FELT IT WAS BEST TO INCLUDE THEM. FARTHER SOUTH...FROM WACO TO ATHENS...LESS RAIN FELL IN THIS AREA LAST THURSDAY...BUT QUICK TOTALS OF 2-3 INCHES ARE POSSIBLE THIS EVENING. FOR WACO/TEMPLE/KILLEEN ONLY AROUND 2 INCHES ARE FORECAST...BUT AGAIN URBAN INFRASTRUCTURE MAY EXACERBATE ANY FLOODING...SO THEY WERE INCLUDED IN THE WATCH TOO. BECAUSE THE UPPER LEVEL TROUGH WILL BE SLOW TO MOVE EAST...CONTINUED SOUTHERLY FLOW ALOFT BEHIND THE FRONT/LINE OF STORMS WILL OCCUR THIS EVENING. THUS THE LINE OF STORMS WILL LIKELY BE SUCCEEDED BY A FEW HOURS OF STEADY LIGHT TO MODERATE STRATIFORM RAINS...ESPECIALLY ACROSS THE WATCH AREA. THIS ACTIVITY SHOULD END FROM NORTHWEST TO SOUTHEAST LATE TONIGHT...BUT MAY LINGER OVER THE SOUTHEAST ZONES INTO TUESDAY MORNING. TUESDAY SHOULD BE DRY FOR THE REMAINDER OF THE AREA WITH MOSTLY CLOUDY AND COOL CONDITIONS AS COOLER AIR POURS INTO THE REGION BEHIND THE FRONT. FORECAST HIGH TEMPS MAY BE TOO WARM...BUT IT WOULD ONLY TAKE AN HOUR OR TWO OF AFTERNOON MAY SUNSHINE TO WARM US INTO THE MID 60S...SO STAYED CONSERVATIVE THERE. THE STRONGEST UPPER LEVEL FORCING WILL CROSS THE REGION TUESDAY EVENING BUT THE AIRMASS WILL BE PRETTY WORKED OVER. HOWEVER THIS FORCING SHOULD RESULT IN SCATTERED ELEVATED SHOWERS AND A FEW STORMS OVER THE REGION AND SHOULD SQUEEZE OUT ANOTHER TENTH TO QUARTER INCH OF RAINFALL. HAVE BUMPED POPS UP TUESDAY NIGHT AS MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT ON THIS ROUND. OTHERWISE THE REMAINDER OF THE FORECAST LOOKS QUIET AND VERY NICE FOR MID TO LATE MAY. DRY NORTHWESTERLY FLOW ALOFT WILL PREVAIL THROUGH THE WEEKEND LEADING TO CLEAR SKIES AND LIGHT WINDS. GOOD RADIATIONAL COOLING WEDNESDAY NIGHT WILL SEND LOW TEMPS DOWN INTO THE 40S AREA WIDE...AND WACO MAY BREAK ITS RECORD LOW OF 46. HIGHS IN THE UPPER 60S ARE EXPECTED THURSDAY...BUT TEMPS SHOULD WARM INTO THE 70S FRIDAY AND THE 80S BY THE WEEKEND. DRY WEATHER WILL CONTINUE INTO NEXT WEEK WITH TEMPS WARMING TO ABOVE NORMAL. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 83 54 66 51 68 / 90 80 20 40 10 WACO, TX 87 57 65 51 69 / 70 100 40 60 10 PARIS, TX 84 56 63 51 64 / 70 90 20 50 20 DENTON, TX 80 52 65 49 68 / 80 70 20 40 10 MCKINNEY, TX 83 53 64 50 68 / 90 80 20 40 10 DALLAS, TX 84 55 65 52 68 / 90 80 20 50 10 TERRELL, TX 85 57 64 51 67 / 70 90 20 50 20 CORSICANA, TX 86 59 64 52 67 / 60 100 40 60 20 TEMPLE, TX 87 58 64 52 69 / 50 100 50 60 10 MINERAL WELLS, TX 80 50 66 47 71 / 70 60 20 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH LATE TONIGHT FOR TXZ094-095-104>107-119>123-134-135-145>148-158>162- 174-175. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
634 AM CDT MON MAY 12 2014 .AVIATION... /12Z TAFS/ Stratus will remain over the Heartland and Northwest Hill Country through mid morning and then will dissipate. Going with MVFR CIGS at the KJCT and KBBD terminals until 16Z. Mainly VFR conditions are expected the rest of the TAF forecast. Isolated to scattered thunderstorms will be possible east of an Abilene to San Angelo line mainly this afternoon and tonight. Storms may even be more numerous by tonight east of a Coleman to Junction line. The models are developing an MCS along a cold front by 06Z Tuesday and moving it slowly east into central Texas. However, confidence is only high enough to add VCTS to the terminals through 02Z Tuesday. Winds will be south and then become north as cold front moves through West Central Texas today and this evening. && .PREV DISCUSSION... /ISSUED 442 AM CDT MON MAY 12 2014/ SHORT TERM... (Today and Tonight) WV imagery this morning was showing and a strong upper level trough over the central and southern Rockies with a mid level speed max of 50 to 70 knots rotating out in the Plains. Upper level flow has backed to southwest over Texas. Also, a lot mid and upper subsidence evident which is still resulting in a strong cap over West Central Texas. At the surface, a cold front was located along a Quanah to Seminole line. A dryline extended south along a Wink to Sanderson line. Not much happening yet convection wise as low level inhibition and cap is still holding strong. A few showers have developed just behind the cold front across northwest Texas. The airmass was very moist across our area with southerly flow and dewpoints in the mid to upper 60s. For today, the chance of showers and thunderstorms will increase mid morning through the afternoon across mainly the eastern half of the CWFA. The cold front will continue southeast into West Central Texas and will probably slow its forward speed. Scattered showers and thunderstorms will develop along and behind the front as elevated instability erases the cap. The HRRR convective allowing model is showing best coverage of activity east of an Abilene to San Angelo line. The combination of good instability in the warm sector and weak 0-6KM shear of 25 to 30 knots will result in multicell storms with possible brief supercell structures. A few strong to severe storms are possible across mainly the Heartland and Northwest Hill Country. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning. Going with mainly chance to slight chance POPS for today. Temperatures will be cooler with highs in the 80s. For tonight, There will be a chance of showers thunderstorms across much of our area with better coverage of storms east of a Coleman to Sonora line. a few storms may be severe. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning mainly before 06Z Tuesday. The bigger focus will be the potential for locally heavy rainfall across the Heartland and Northwest Hill Country, due to good low level southerly flow. moisture flux convergence along a slow moving cold front, PWAT values of 1.5 to 1.75 inches and in the RRQ of highly amplified 250MB jet. Rainfall amounts of 1 to 2 inches with locally heavy amounts are possible along and east of a Brownwood to Junction line. Also, going with LKLY to CAT POPS across the southeast CWFA. LONG TERM... (Tuesday through next Monday) The cold front will be well south of the area early Tuesday morning, with the upper level trough axis over New Mexico. Showers and thunderstorms may be ongoing across far southeast sections early Tuesday morning but will move east of the area by mid to late morning. Additional showers and isolated thunderstorms will be possible across much of the area during the day as lift increases ahead of the approaching upper trough. Moisture will be limited, so precipitation is expected to be light, with most areas seeing one tenth inch or less of rainfall. It will be considerably cooler on Tuesday with highs well below normal for this time of year. NAM guidance looks too cool with highs in the upper 50s, so went with a GFS/NAM blend, which looks more reasonable with highs topping out in the lower 60s. Lingering showers will be possible Tuesday evening over southeast sections, otherwise dry conditions are expected overnight with clearing skies, as drier air filters in behind the departing upper trough. Temperatures will be very chilly Wednesday night with overnight lows in the lower and middle 40s. Dry and cool weather will continue on Wednesday with sunny skies, light winds and highs in the lower 70s. Another cool night is in store Wednesday night with low temperatures again in the 40s. Will maintain a dry forecast Thursday into next weekend with a warming trend through the period. Northwest flow aloft is expected through Saturday, with a short wave ridge overspreading the Plains on Sunday. High temperatures will warm from the mid 80s late week, to the upper 80s and lower 90s by the end of the weekend. Expect overnight lows in the 50s, warming into the 60s through the period. FIRE WEATHER... Elevated fire weather conditions will be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 80 50 63 45 72 / 40 20 20 10 0 San Angelo 86 52 62 43 73 / 30 20 20 10 0 Junction 85 57 64 46 73 / 50 70 40 20 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21/24
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
608 AM CDT MON MAY 12 2014 .AVIATION... CONCERNS...TIMING OF CONVECTION AND WIND SHIFT. ...WIDESPREAD DISRUPTIONS ARE EXPECTED THIS AFTERNOON AT DFW AIRPORT AND DALLAS LOVE FIELD... A COLD FRONT IS STEADILY APPROACHING FROM THE NORTHWEST. ALTHOUGH FRONTS TEND TO SLOW DOWN DURING THE DAYLIGHT HOURS...THE MOTION OF THE BOUNDARY TODAY WILL BE ENHANCED BY CONVECTION. SHOWERS AND THUNDERSTORMS HAVE ALREADY REDEVELOPED ALONG THE BOUNDARY DURING THE PREDAWN HOURS...AND ADDITIONAL ACTIVITY MAY DEVELOP WELL IN ADVANCE OF THE WIND SHIFT THIS MORNING. THIS ACTIVITY WILL PRIMARILY IMPACT NORTHWEST ARRIVALS THIS MORNING...BUT SOME SHOWERS OR STORMS COULD OCCUR NEAR METROPLEX AIRPORTS BEFORE MIDDAY. THE BULK OF THE THUNDERSTORM ACTIVITY IN THE IMMEDIATE METROPLEX WILL BE DURING THE AFTERNOON HOURS...WHEN A LINE OF STORMS MOVES SLOWLY THROUGH. WINDS MAY BE CHAOTIC WITH THE ACTIVITY...BUT NORTHWEST WINDS SHOULD PREVAIL BY MID-AFTERNOON. ALTHOUGH SOME STRONG OR MARGINALLY SEVERE STORMS WILL BE POSSIBLE WITHIN THE LINE...THE MAIN IMPACTS TO COMMERCIAL AVIATION TODAY WILL BE FROM LIGHTNING. SIMILAR IMPACTS ARE EXPECTED AT CENTRAL TEXAS AIRPORTS...BUT THE ACTIVITY AND WIND SHIFT WILL LIKELY OCCUR A FEW HOURS LATER THAN IN THE METROPLEX. THE FRONTAL PASSAGE WILL NOT BRING AN END TO THE PRECIPITATION... AND RAIN WILL CONTINUE MUCH OF THE EVENING. THE 850MB FRONT MAY BE AS MUCH AS 12 HOURS BEHIND THE SURFACE BOUNDARY...AND BUOYANT GULF AIR WILL MAINTAIN INSTABILITY ABOVE THE FRONTAL LAYER SUFFICIENT FOR THUNDER. HOWEVER...THE THUNDER THIS EVENING AND OVERNIGHT IS EXPECTED TO BE ISOLATED. TO REDUCE THE NUMBER OF HOURS WITH THUNDER IN THE TAFS...WILL CARRY PREVAILING RAIN WITHOUT THUNDER. 25 && .PREV DISCUSSION... /ISSUED 437 AM CDT MON MAY 12 2014/ THE POTENT UPPER LEVEL LOW OVER THE FOUR CORNERS THAT WAS RESPONSIBLE FOR SNOW IN DENVER YESTERDAY WILL EJECT NORTHEAST OUT INTO THE PLAINS TODAY...BUT ADDITIONAL UPPER ENERGY WILL DROP INTO THE BASE OF A DEEPENING LONGWAVE TROUGH TODAY. THIS UPPER TROUGH WILL ENGULF THE CENTRAL US BY TOMORROW...A PATTERN THAT IS VERY UNUSUAL FOR MID MAY. THIS SYSTEM HAS TAPPED INTO A CANADIAN AIRMASS AND HAS SENT AN UNSEASONABLY STRONG COLD FRONT BARRELING SOUTH. AT 4AM...THIS FRONT WAS LOCATED JUST SOUTH OF LUBBOCK TO NEAR VERNON TO EL RENO OKLAHOMA AND WAS MOVING SOUTHEAST AT 15 TO 20MPH. THE FRONT IS AHEAD OF MOST MODEL PROJECTIONS...WHICH IS NOT SURPRISING GIVEN THE COLD AIR BEHIND IT. THE RAP HAS A GOOD HANDLE ON THE FRONT/S SPEED AND IT WILL BE USED FOR TIMING. THE FRONT WILL ARRIVE INTO THE NORTHWEST CWA BY MID-MORNING AND CONTINUE TO TRACK SOUTHEAST...BUT SLOW DOWN A BIT DUE TO DAYTIME HEATING. THE FRONT SHOULD REACH A SHERMAN TO DFW TO COMANCHE LINE BY MID-AFTERNOON. THE AIRMASS AHEAD OF THE FRONT WILL BE WARM AND MOIST...WITH SEVERAL DAYS OF SOUTHERLY FLOW NOW BRINGING PRECIPITABLE WATER VALUES UP TO 1.75 TO 2 INCHES. SURFACE BASED CAPE WILL PEAK AROUND 2000-2500 J/KG THIS AFTERNOON AS TEMPS WARM INTO THE MID 80S. DAYTIME HEATING AND FORCING FOR ASCENT FROM THE UPPER LEVEL TROUGH WILL LIFT/ERODE THE WEAK CAPPING INVERSION...AND THUS CONVECTION WILL INCREASE IN COVERAGE ALONG THE FRONT BY LATE MORNING. BULK LAYER SHEAR IS FAIRLY WEAK...ON THE ORDER OF 25KT...SO MULTICELLULAR CONVECTIVE MODES ARE EXPECTED. GIVEN THE HIGH INSTABILITY AND WEAK SHEAR...SOME SEVERE WIND/HAIL REPORTS ARE POSSIBLE TODAY WITH THE STRONGEST STORMS. CONVECTION ALONG THE FRONT WILL LIKELY CONGEAL INTO A SOLID LINE OF THUNDERSTORMS BY MID-AFTERNOON...WITH THE LINE CONTINUING TO GROW UPSCALE INTO A FORMIDABLE LINEAR MCS BY THE EVENING HOURS. MCS PROPAGATION VECTORS AND DIFFLUENT THICKNESS FIELDS ALOFT SUGGEST THAT THE MOVEMENT OF THIS SYSTEM WILL REMAIN FAIRLY SLOW...LIKELY LESS THAN 10-15MPH. THIS FORWARD SPEED SHOULD IN THEORY LIMIT THE DAMAGING WIND THREAT THIS EVENING OVER THE SOUTHEAST HALF OF THE CWA...BUT WILL RESULT IN ENHANCED RAINFALL TOTALS. THE MCS WILL LIKELY HAVE SLOWER WEST TO EAST MOVEMENT THAN NORTH TO SOUTH...AND THUS THE ORIENTATION OF THE LINE SUGGESTS THAT EASTERN ZONES WILL HAVE A GREATER RISK FOR PROLONGED HEAVY RAINFALL. EXPECT THE LINE TO PUSH THROUGH THE SOUTHWEST ZONES FAIRLY QUICKLY...LIKELY REACHING A LAMPASAS TO WACO LINE BY 6 PM. A TIGHT RAINFALL GRADIENT IS FORECAST OVER THE CWA WITH LESS THAN A HALF INCH EXPECTED OVER THE NW ZONES...TO 1-2 INCHES IN A BAND FROM THE SHERMAN AREA TO THE METROPLEX TO COMANCHE...AND 2-3 INCHES SOUTH AND EAST OF A PARIS TO GREENVILLE TO HILLSBORO LINE. THIS LATTER REGION WAS THE SAME AREA THAT RECEIVED A SWATH OF 2-4 INCHES OF RAIN THURSDAY AND SOILS ARE ALREADY SATURATED. THUS A FLASH FLOOD WATCH WAS ISSUED FOR LOCATIONS ALONG AND SOUTHEAST OF A BONHAM TO DALLAS TO TEMPLE LINE. WHILE WE DONT EXPECT MOST OF DALLAS AND COLLIN COUNTIES TO RECEIVE MORE THAN 2 INCHES...GIVEN THE URBAN DEVELOPMENT THERE AND THE FACT THAT THE SOUTHEAST PARTS OF THESE COUNTIES DID SEE OVER 4 INCHES...FELT IT WAS BEST TO INCLUDE THEM. FARTHER SOUTH...FROM WACO TO ATHENS...LESS RAIN FELL IN THIS AREA LAST THURSDAY...BUT QUICK TOTALS OF 2-3 INCHES ARE POSSIBLE THIS EVENING. FOR WACO/TEMPLE/KILLEEN ONLY AROUND 2 INCHES ARE FORECAST...BUT AGAIN URBAN INFRASTRUCTURE MAY EXACERBATE ANY FLOODING...SO THEY WERE INCLUDED IN THE WATCH TOO. BECAUSE THE UPPER LEVEL TROUGH WILL BE SLOW TO MOVE EAST...CONTINUED SOUTHERLY FLOW ALOFT BEHIND THE FRONT/LINE OF STORMS WILL OCCUR THIS EVENING. THUS THE LINE OF STORMS WILL LIKELY BE SUCCEEDED BY A FEW HOURS OF STEADY LIGHT TO MODERATE STRATIFORM RAINS...ESPECIALLY ACROSS THE WATCH AREA. THIS ACTIVITY SHOULD END FROM NORTHWEST TO SOUTHEAST LATE TONIGHT...BUT MAY LINGER OVER THE SOUTHEAST ZONES INTO TUESDAY MORNING. TUESDAY SHOULD BE DRY FOR THE REMAINDER OF THE AREA WITH MOSTLY CLOUDY AND COOL CONDITIONS AS COOLER AIR POURS INTO THE REGION BEHIND THE FRONT. FORECAST HIGH TEMPS MAY BE TOO WARM...BUT IT WOULD ONLY TAKE AN HOUR OR TWO OF AFTERNOON MAY SUNSHINE TO WARM US INTO THE MID 60S...SO STAYED CONSERVATIVE THERE. THE STRONGEST UPPER LEVEL FORCING WILL CROSS THE REGION TUESDAY EVENING BUT THE AIRMASS WILL BE PRETTY WORKED OVER. HOWEVER THIS FORCING SHOULD RESULT IN SCATTERED ELEVATED SHOWERS AND A FEW STORMS OVER THE REGION AND SHOULD SQUEEZE OUT ANOTHER TENTH TO QUARTER INCH OF RAINFALL. HAVE BUMPED POPS UP TUESDAY NIGHT AS MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT ON THIS ROUND. OTHERWISE THE REMAINDER OF THE FORECAST LOOKS QUIET AND VERY NICE FOR MID TO LATE MAY. DRY NORTHWESTERLY FLOW ALOFT WILL PREVAIL THROUGH THE WEEKEND LEADING TO CLEAR SKIES AND LIGHT WINDS. GOOD RADIATIONAL COOLING WEDNESDAY NIGHT WILL SEND LOW TEMPS DOWN INTO THE 40S AREA WIDE...AND WACO MAY BREAK ITS RECORD LOW OF 46. HIGHS IN THE UPPER 60S ARE EXPECTED THURSDAY...BUT TEMPS SHOULD WARM INTO THE 70S FRIDAY AND THE 80S BY THE WEEKEND. DRY WEATHER WILL CONTINUE INTO NEXT WEEK WITH TEMPS WARMING TO ABOVE NORMAL. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 83 54 66 51 68 / 90 80 20 40 10 WACO, TX 87 57 65 51 69 / 70 100 40 60 10 PARIS, TX 84 56 63 51 64 / 70 90 20 50 20 DENTON, TX 80 52 65 49 68 / 80 70 20 40 10 MCKINNEY, TX 83 53 64 50 68 / 90 80 20 40 10 DALLAS, TX 84 55 65 52 68 / 90 80 20 50 10 TERRELL, TX 85 57 64 51 67 / 70 90 20 50 20 CORSICANA, TX 86 59 64 52 67 / 60 100 40 60 20 TEMPLE, TX 87 58 64 52 69 / 50 100 50 60 10 MINERAL WELLS, TX 79 50 66 47 71 / 70 60 20 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH LATE TONIGHT FOR TXZ094-095-104>107-119>123-134-135-145>148-158>162- 174-175. && $$ 25/92
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
843 AM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST IS GOING TO KEEP OUR REGION IN A INCREASINGLY HUMID AIRMASS. A SLOW MOVING FRONT ENTERS THE REGION BY THURSDAY AND SLIDES EAST FRIDAY. A COOLER AIRMASS FOLLOWS THIS FRONT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 700 AM EDT MONDAY... FEW SHOWERS ACROSS GREENBRIER COUNTY WV THIS MORNING...OTHERWISE MAINLY SEEING SOME AC/CI. UPDATES JUST REFLECT TRENDS IN TEMPS/SKY COVER WITH ISOLATED POPS IN THE NW CWA. PREVIOUS VALID DISCUSSION... DESPITE INCREASING 5H HEIGHTS TODAY...WILL STILL SEE A COUPLE OF EMBEDDED SHORTWAVES RIDE THE NRN CENTER OF THE HIGH ACROSS OUR AREA. EARLY THIS MORNING...THERE IS A WEAK SHORTWAVE MOVING ACROSS WV WITH TAIL END OF SHOWERS PUSHING EAST BETWEEN BKW-CRW BUT WEAKENING. THE LATEST HRRR SHOWS THIS AREA MAYBE SCRAPING NRN GREENBRIER AND BATH. OVERALL...SHOULD BE A DRY MORNING WITH PATCH FOG IN THE VALLEYS/RIVER AREAS. TODAY...THE SFC HIGH OFF THE COAST WILL CONTINUE TO KEEP MOISTURE STREAMING NWD INTO THE CENTRAL APPALACHIANS. HEATING WILL LEAD TO INSTABILITY AND OVERALL WEAK FORCING FAVORS SCATTERED SHOWERS AND STORMS POPPING AROUND MIDDAY IN THE MTNS WITH STEERING FLOW TAKING THEM EAST TO THE BLUE RIDGE AND FOOTHILLS DURING THE AFTERNOON. FURTHER SOUTH ACROSS NC/SOUTHSIDE VA...AIRMASS MAY BE JUST CAPPED ENOUGH TO LIMIT CONVECTION...ALTHOUGH A FEW SHOULD SKIRT BY THIS EVENING WHEN CAP WEAKENS. OVERALL KEPT POPS UNDER HIGH CHANCE...BUT WILL BE A CASE WHERE 1/3-1/2 OF A COUNTY GETS RAINED ON...WHILE THE OTHER HALF MISSES OUT. FOR HIGHS WILL SEE MOSTLY SUNNY SKIES EARLY WITH CU/TCU DEVELOPING WITH SOME AC/CI OVERTOP. THIS WILL LIMIT HEATING MAINLY OVER THE MOUNTAINS BUT STILL LOOKING AT TEMPS RUNNING AROUND 10 DEGREES ABOVE NORMAL. HIGHS RANGING FROM THE UPPER 70S/LOWER 80S WEST TO NEAR 90 SOUTHEAST. TONIGHT...CONVECTION WEAKENS WITH LOSS OF HEATING. THE 00Z WRF/NAM HOLD ONTO ACTIVITY INTO LATE EVENING WHILE THE OTHER MODELS SHOWING LITTLE TO NONE AFTER 00Z/8 PM. WILL LEAN TOWARD THE HIGHER RES MODELS SINCE ANY OUTFLOW COULD KEEP A SHOWER/STORM GOING PAST 8 PM. BY MIDNIGHT WILL BE CLEAR TO PARTLY CLOUDY AND HUMID WITH LOWS IN THE UPPER 50S TO LOWER 60S. FOG COULD BECOME AN ISSUE SINCE RAIN SHOWERS ARE EXPECTED THIS AFTERNOON...ALTHOUGH COVERAGE WILL BE PATCHY. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 415 AM EDT MONDAY... UPPER LEVEL RIDGING WILL BE FIRMLY IN PLACE TUESDAY MORNING ACROSS THE EASTERN SEABOARD...WHICH WILL RESULT IN VERY SUMMER LIKE TEMPERATURES. EXPECT AFTERNOON HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS... TO THE LOW 90S ACROSS THE SOUTHSIDE. STRONG HEATING AND CONTINUED MOISTURE INFLOW SHOULD HELP KICK OFF A FEW SHOWERS AND THUNDERSTORMS DURING LATE AFTERNOON AND EARLY EVENING... HOWEVER THE RIDGING WILL KEEP THIS ACTIVITY SPOTTY AT BEST AND DISORGANIZED. WILL BE KEEPING AN EYE ON A COLD FRONT BACK DOORING ITS WAY SOUTHWARD FROM NEW ENGLAND DURING THE AFTERNOON AND EVENING...BUT DO NOT THINK IT WILL APPROACH CLOSE ENOUGH TO ENHANCE CONVECTION OVER OUR AREA. AT ANY RATE...ANY CONVECTION SHOULD GRADUALLY FIZZLE TOWARD SUNSET...AND PATCHY FOG WILL BE POSSIBLE TUESDAY NIGHT...ESPECIALLY IN AREAS WHICH DO RECEIVE A DOWNPOUR. BETTER CHANCES FOR SHOWER AND THUNDERSTORMS WILL OCCUR ON WEDNESDAY AS UPPER LEVEL RIDGING BEGINS TO SHIFT EAST...WHILE THE BACK DOOR FRONT STALLS ACROSS NORTHERN VIRGINIA JUST OUTSIDE OUR FORECAST REGION. ANOTHER DAY OF STRONG HEATING AS HIGHS REACH INTO THE 80S MOST LOCATIONS...COMBINED WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE NEARBY FRONT...WILL LEAD TO HIGHER RAIN CHANCES ACROSS THE MOUNTAINS AND THE PIEDMONT NORTH OF HIGHWAY 460. THE INCREASED INSTABILITY WILL ALLOW FOR GREATER POTENTIAL FOR ORGANIZED THUNDERSTORM ACTIVITY...AND A FEW STORMS WILL LIKELY BECOME STRONG DURING LATE AFTERNOON AND EARLY EVENING...CAPABLE OF PRODUCING LOCALLY STRONG WINDS AND HAIL. WILL SEE THE BOUNDARY ACROSS NORTHERN VIRGINIA LIFT TOWARD NEW ENGLAND DURING LATE EVENING AS A WARM FRONT...WHILE A STRONG COLD FRONT APPROACHES OUR REGION FROM THE WEST. THE COLD FRONT WILL ENTER OUR WESTERN MOST COUNTIES DURING MID AFTERNOON...RESULTING IN WAVES OF LOCALLY HEAVY RAIN AS UPPER LEVEL DISTURBANCES PASS OVERHEAD ALONG THE BOUNDARY. MODELS ARE PICKING UP ON AT LEAST ONE STRONG WAVE POTENTIALLY BRINGING HEAVY RAIN TO THE FOOTHILLS AND THE PIEDMONT DURING THE EVENING...AND POSSIBLY A SECOND WAVE IF THE COLD FRONT SLOWS/STALLS BEFORE EXITING OUR REGION DURING EARLY FRIDAY MORNING. STILL NOT ENOUGH CONFIDENCE IN THE MODELS TO TACK DOWN RAINFALL AMOUNTS...BUT IT IS LOOKING SAFE TO SAY THAT THE MUCH OF THE REGION WILL RECEIVE BETWEEN ONE AND TWO INCHES FOR THE THURSDAY AND EARLY FRIDAY TIME PERIOD...WITH SOME AREAS PICKING IN EXCESS OF 3 INCHES...ESPECIALLY ALONG THE BLUE RIDGE. MODELS ARE IN DECENT AGREEMENT THAT THE FRONT AND ASSOCIATED HEAVY RAIN WILL BE EAST OF OUR AREA DURING EARLY FRIDAY AFTERNOON... LEAVING ONLY RESIDUAL SHOWER ACTIVITY...AS WELL AS A SHARP DROP IN TEMPERATURES AS A DEEP UPPER TROUGH APPROACHES FROM THE WEST. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 400 PM EDT SUNDAY... AN AMPLIFIED MID-UPPER LEVEL MEAN TROUGH SETTLES OVER THE ERN HALF OF THE CONUS FOR THE LATTER HALF OF THE WEEK AND INTO NEXT WEEKEND. AS WE TRANSITION INTO THE WEEKEND...FLOW BECOMES BLOCKY WITH A DEEP QUASI-STATIONARY...ALMOST WINTERLIKE UPPER LOW PARKED OVER THE GREAT LAKES REGION. 850MB TEMPS WILL DROP INTO THE 3C TO 6C RANGE FOR MOST OF THE CWA AND LINGER IN THIS RANGE FOR SEVERAL DAYS. SEVERAL SPOKES OF PVA ARE EXPECTED TO ROTATE AROUND THIS UPPER LOW WHICH SUGGESTS POTENTIAL FOR CLOUDS AND SHOWERS... ESPECIALLY ACROSS THE MOUNTAINS. TEMPERATURES WILL TREND TO THE COOLER SIDE OF NORMAL. FORTUNATELY...CLOUDS...SHOWERS...AND A BIT OF A NW BREEZE SHOULD MITIGATE FROST POTENTIAL. NONETHELESS...IT WILL BE QUITE CHILLY WITH HIGHS IN THE 60S AND LOWS IN THE 40S ACROSS MUCH OF THE REGION...A BIG CONTRAST FROM THE WARMTH THE FIRST HALF OF THIS WEEK. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... AS OF 710 AM EDT MONDAY... NOT MUCH CHANGE FROM PREVIOUS TAFS. MODELS STILL SHOWING A SCATTERING OF CONVECTION BETWEE 16-18Z TODAY OVER THE MOUNTAINS...AND SKIRTING TOWARD LYH BY 20Z. STILL TOO LOOSE OF COVERAGE TO HAVE ANYTHING MORE THAN VCTS IN THE TAFS ASIDE FROM BLF. ASIDE FROM THE STORMS...EXPECT VFR. THIS EVENING...CONVECTION WANES AND SKIES WILL BE CLEAR/PC AND VFR. SOME MVFR VSBYS AND POSSIBLY LOWER OVERNIGHT. WILL HAVE TO SEE WHERE IT RAINS THIS AFTERNOON WHICH CAN SET UP MORE FOG OVERNIGHT. RIGHT NOW CONFIDENCE HIGH THAT AT LEAST THE CLIMO FAVORED STATIONS OF LWB/BCB GET MVFR VSBYS OVERNIGHT. FORECAST FAVORS SLOWING OF THE FRONT SO THAT NOW EVEN WEDNESDAY COULD HAVE LESS COVERAGE. UNTIL THE FRONT GETS CLOSER EXPECT MAINLY VFR WITH POP UP STORMS IN THE AFTERNOON...AND MAYBE FOG ENTERING THE PICTURE MORE OVERNIGHT AT MOST SITES OUTSIDE OF BLF/LWB. HEAVY RAINS AND STORMS WILL BE AFFECTING OUR REGION BY THURSDAY AND COULD LINGER INTO EARLY FRIDAY. SO DURING THE WED-FRI TIME FRAME GOOD CHANCE OF SUB VFR VSBYS/CIGS. && .CLIMATE... TEMPERATURES REMAIN VERY WARM MONDAY AND TUESDAY. MONDAYS RECORD HIGH FOR BLUEFIELD WV IS 83 DEGREES AND IN BLACKSBURG VA IT IS 85 DEGREES. THESE ARE THE ONLY TWO LOCATIONS MONDAY WHERE HIGH TEMPERATURES MAY TIE OR EXCEED THE CURRENT RECORD HIGH TEMPERATURE. TEMPERATURES ARE EXPECTED TO BE EVEN WARMER ON TUESDAY ALLOWING ALL CLIMATE STATIONS TO HAVE A SHOT AT BREAKING A RECORD. HERE ARE THE CURRENT RECORD HIGH TEMPERATURES FOR TUESDAY: MAY 13 ROA92 (2000) LYH92 (1956) DAN93 (2000) BCB84 (2000) BLF83 (2010) LWB 84 (2000) && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PC/WP NEAR TERM...WP SHORT TERM...NF LONG TERM...PM AVIATION...RCS/WP CLIMATE...CF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
718 AM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTHEAST COAST IS GOING TO KEEP OUR REGION IN A INCREASINGLY HUMID AIRMASS. A SLOW MOVING FRONT ENTERS THE REGION BY THURSDAY AND SLIDES EAST FRIDAY. A COOLER AIRMASS FOLLOWS THIS FRONT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 700 AM EDT MONDAY... FEW SHOWERS ACROSS GREENBRIER COUNTY WV THIS MORNING...OTHERWISE MAINLY SEEING SOME AC/CI. UPDATES JUST REFLECT TRENDS IN TEMPS/SKY COVER WITH ISOLATED POPS IN THE NW CWA. PREVIOUS VALID DISCUSSION... DESPITE INCREASING 5H HEIGHTS TODAY...WILL STILL SEE A COUPLE OF EMBEDDED SHORTWAVES RIDE THE NRN CENTER OF THE HIGH ACROSS OUR AREA. EARLY THIS MORNING...THERE IS A WEAK SHORTWAVE MOVING ACROSS WV WITH TAIL END OF SHOWERS PUSHING EAST BETWEEN BKW-CRW BUT WEAKENING. THE LATEST HRRR SHOWS THIS AREA MAYBE SCRAPING NRN GREENBRIER AND BATH. OVERALL...SHOULD BE A DRY MORNING WITH PATCH FOG IN THE VALLEYS/RIVER AREAS. TODAY...THE SFC HIGH OFF THE COAST WILL CONTINUE TO KEEP MOISTURE STREAMING NWD INTO THE CENTRAL APPALACHIANS. HEATING WILL LEAD TO INSTABILITY AND OVERALL WEAK FORCING FAVORS SCATTERED SHOWERS AND STORMS POPPING AROUND MIDDAY IN THE MTNS WITH STEERING FLOW TAKING THEM EAST TO THE BLUE RIDGE AND FOOTHILLS DURING THE AFTERNOON. FURTHER SOUTH ACROSS NC/SOUTHSIDE VA...AIRMASS MAY BE JUST CAPPED ENOUGH TO LIMIT CONVECTION...ALTHOUGH A FEW SHOULD SKIRT BY THIS EVENING WHEN CAP WEAKENS. OVERALL KEPT POPS UNDER HIGH CHANCE...BUT WILL BE A CASE WHERE 1/3-1/2 OF A COUNTY GETS RAINED ON...WHILE THE OTHER HALF MISSES OUT. FOR HIGHS WILL SEE MOSTLY SUNNY SKIES EARLY WITH CU/TCU DEVELOPING WITH SOME AC/CI OVERTOP. THIS WILL LIMIT HEATING MAINLY OVER THE MOUNTAINS BUT STILL LOOKING AT TEMPS RUNNING AROUND 10 DEGREES ABOVE NORMAL. HIGHS RANGING FROM THE UPPER 70S/LOWER 80S WEST TO NEAR 90 SOUTHEAST. TONIGHT...CONVECTION WEAKENS WITH LOSS OF HEATING. THE 00Z WRF/NAM HOLD ONTO ACTIVITY INTO LATE EVENING WHILE THE OTHER MODELS SHOWING LITTLE TO NONE AFTER 00Z/8 PM. WILL LEAN TOWARD THE HIGHER RES MODELS SINCE ANY OUTFLOW COULD KEEP A SHOWER/STORM GOING PAST 8 PM. BY MIDNIGHT WILL BE CLEAR TO PARTLY CLOUDY AND HUMID WITH LOWS IN THE UPPER 50S TO LOWER 60S. FOG COULD BECOME AN ISSUE SINCE RAIN SHOWERS ARE EXPECTED THIS AFTERNOON...ALTHOUGH COVERAGE WILL BE PATCHY. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 415 AM EDT MONDAY... UPPER LEVEL RIDGING WILL BE FIRMLY IN PLACE TUESDAY MORNING ACROSS THE EASTERN SEABOARD...WHICH WILL RESULT IN VERY SUMMER LIKE TEMPERATURES. EXPECT AFTERNOON HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS... TO THE LOW 90S ACROSS THE SOUTHSIDE. STRONG HEATING AND CONTINUED MOISTURE INFLOW SHOULD HELP KICK OFF A FEW SHOWERS AND THUNDERSTORMS DURING LATE AFTERNOON AND EARLY EVENING... HOWEVER THE RIDGING WILL KEEP THIS ACTIVITY SPOTTY AT BEST AND DISORGANIZED. WILL BE KEEPING AN EYE ON A COLD FRONT BACK DOORING ITS WAY SOUTHWARD FROM NEW ENGLAND DURING THE AFTERNOON AND EVENING...BUT DO NOT THINK IT WILL APPROACH CLOSE ENOUGH TO ENHANCE CONVECTION OVER OUR AREA. AT ANY RATE...ANY CONVECTION SHOULD GRADUALLY FIZZLE TOWARD SUNSET...AND PATCHY FOG WILL BE POSSIBLE TUESDAY NIGHT...ESPECIALLY IN AREAS WHICH DO RECEIVE A DOWNPOUR. BETTER CHANCES FOR SHOWER AND THUNDERSTORMS WILL OCCUR ON WEDNESDAY AS UPPER LEVEL RIDGING BEGINS TO SHIFT EAST...WHILE THE BACK DOOR FRONT STALLS ACROSS NORTHERN VIRGINIA JUST OUTSIDE OUR FORECAST REGION. ANOTHER DAY OF STRONG HEATING AS HIGHS REACH INTO THE 80S MOST LOCATIONS...COMBINED WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE NEARBY FRONT...WILL LEAD TO HIGHER RAIN CHANCES ACROSS THE MOUNTAINS AND THE PIEDMONT NORTH OF HIGHWAY 460. THE INCREASED INSTABILITY WILL ALLOW FOR GREATER POTENTIAL FOR ORGANIZED THUNDERSTORM ACTIVITY...AND A FEW STORMS WILL LIKELY BECOME STRONG DURING LATE AFTERNOON AND EARLY EVENING...CAPABLE OF PRODUCING LOCALLY STRONG WINDS AND HAIL. WILL SEE THE BOUNDARY ACROSS NORTHERN VIRGINIA LIFT TOWARD NEW ENGLAND DURING LATE EVENING AS A WARM FRONT...WHILE A STRONG COLD FRONT APPROACHES OUR REGION FROM THE WEST. THE COLD FRONT WILL ENTER OUR WESTERN MOST COUNTIES DURING MID AFTERNOON...RESULTING IN WAVES OF LOCALLY HEAVY RAIN AS UPPER LEVEL DISTURBANCES PASS OVERHEAD ALONG THE BOUNDARY. MODELS ARE PICKING UP ON AT LEAST ONE STRONG WAVE POTENTIALLY BRINGING HEAVY RAIN TO THE FOOTHILLS AND THE PIEDMONT DURING THE EVENING...AND POSSIBLY A SECOND WAVE IF THE COLD FRONT SLOWS/STALLS BEFORE EXITING OUR REGION DURING EARLY FRIDAY MORNING. STILL NOT ENOUGH CONFIDENCE IN THE MODELS TO TACK DOWN RAINFALL AMOUNTS...BUT IT IS LOOKING SAFE TO SAY THAT THE MUCH OF THE REGION WILL RECEIVE BETWEEN ONE AND TWO INCHES FOR THE THURSDAY AND EARLY FRIDAY TIME PERIOD...WITH SOME AREAS PICKING IN EXCESS OF 3 INCHES...ESPECIALLY ALONG THE BLUE RIDGE. MODELS ARE IN DECENT AGREEMENT THAT THE FRONT AND ASSOCIATED HEAVY RAIN WILL BE EAST OF OUR AREA DURING EARLY FRIDAY AFTERNOON... LEAVING ONLY RESIDUAL SHOWER ACTIVITY...AS WELL AS A SHARP DROP IN TEMPERATURES AS A DEEP UPPER TROUGH APPROACHES FROM THE WEST. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 400 PM EDT SUNDAY... AN AMPLIFIED MID-UPPER LEVEL MEAN TROUGH SETTLES OVER THE ERN HALF OF THE CONUS FOR THE LATTER HALF OF THE WEEK AND INTO NEXT WEEKEND. AS WE TRANSITION INTO THE WEEKEND...FLOW BECOMES BLOCKY WITH A DEEP QUASI-STATIONARY...ALMOST WINTERLIKE UPPER LOW PARKED OVER THE GREAT LAKES REGION. 850MB TEMPS WILL DROP INTO THE 3C TO 6C RANGE FOR MOST OF THE CWA AND LINGER IN THIS RANGE FOR SEVERAL DAYS. SEVERAL SPOKES OF PVA ARE EXPECTED TO ROTATE AROUND THIS UPPER LOW WHICH SUGGESTS POTENTIAL FOR CLOUDS AND SHOWERS... ESPECIALLY ACROSS THE MOUNTAINS. TEMPERATURES WILL TREND TO THE COOLER SIDE OF NORMAL. FORTUNATELY...CLOUDS...SHOWERS...AND A BIT OF A NW BREEZE SHOULD MITIGATE FROST POTENTIAL. NONETHELESS...IT WILL BE QUITE CHILLY WITH HIGHS IN THE 60S AND LOWS IN THE 40S ACROSS MUCH OF THE REGION...A BIG CONTRAST FROM THE WARMTH THE FIRST HALF OF THIS WEEK. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... AS OF 710 AM EDT MONDAY... NOT MUCH CHANGE FROM PREVIOUS TAFS. MODELS STILL SHOWING A SCATTERING OF CONVECTION BETWEE 16-18Z TODAY OVER THE MOUNTAINS...AND SKIRTING TOWARD LYH BY 20Z. STILL TOO LOOSE OF COVERAGE TO HAVE ANYTHING MORE THAN VCTS IN THE TAFS ASIDE FROM BLF. ASIDE FROM THE STORMS...EXPECT VFR. THIS EVENING...CONVECTION WANES AND SKIES WILL BE CLEAR/PC AND VFR. SOME MVFR VSBYS AND POSSIBLY LOWER OVERNIGHT. WILL HAVE TO SEE WHERE IT RAINS THIS AFTERNOON WHICH CAN SET UP MORE FOG OVERNIGHT. RIGHT NOW CONFIDENCE HIGH THAT AT LEAST THE CLIMO FAVORED STATIONS OF LWB/BCB GET MVFR VSBYS OVERNIGHT. FORECAST FAVORS SLOWING OF THE FRONT SO THAT NOW EVEN WEDNESDAY COULD HAVE LESS COVERAGE. UNTIL THE FRONT GETS CLOSER EXPECT MAINLY VFR WITH POP UP STORMS IN THE AFTERNOON...AND MAYBE FOG ENTERING THE PICTURE MORE OVERNIGHT AT MOST SITES OUTSIDE OF BLF/LWB. HEAVY RAINS AND STORMS WILL BE AFFECTING OUR REGION BY THURSDAY AND COULD LINGER INTO EARLY FRIDAY. SO DURING THE WED-FRI TIME FRAME GOOD CHANCE OF SUB VFR VSBYS/CIGS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PC/WP NEAR TERM...WP SHORT TERM...NF LONG TERM...PM AVIATION...RCS/WP
AREA FORECAST DISCUSSION
NWS PUEBLO CO
341 PM MDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 340 PM MDT MON MAY 12 2014 ...HEAVY SNOW CONTINUES FOR THE CONTINENTAL DIVIDE...WITH FREEZING TEMPERATURES FOR THE SOUTHEAST PLAINS TONIGHT... ENERGY DROPPING DOWN THE WEST SIDE OF THE UPPER TROF WILL KEEP SNOW SHOWERS GOING ACROSS SOUTHERN AND WESTERN PORTIONS OF THE AREA. LAPSE RATES ARE STEEP BENEATH THE UPPER TROF ALOFT..AND SNOW HAS BEEN REALLY COMING DOWN IN WEB CAMS AT WOLF CREEK. VIS IS DOWN TO 1/4 MILE AS OF THIS LAST HOUR. ROADWAYS STILL LOOK CLEAR...BUT WITH TEMPERATURES ALREADY IN THE 20S ACROSS THE HIGHER ELEVATIONS...IT WOULD NOT TAKE MUCH MORE COOLING FOR SNOW TO BEGIN TO STICK. NAM12...GFS...AND RAP ALL KEEP HEAVY SNOW CONTINUING THROUGH THE OVERNIGHT HOURS...THOUGH MAJORITY WILL LIKELY FALL BEFORE MIDNIGHT. FOR THAT REASON...UPGRADED THE WINTER WEATHER ADVISORIES FOR THE HIGHER ELEVATIONS OF THE EASTERN SAN JUANS AND LA GARITAS TO A WINTER STORM WARNING WITH AN EARLIER FORECAST PACKAGE UPDATE. EASTERLY UPSLOPE FLOW INTO THE EASTERN SLOPES OF THESE RANGES WILL ALSO LEAD TO FAIRLY HEALTHY SNOW AMOUNTS FOR THE WESTERN SIDE OF THE SAN LUIS VALLEY. CDOT WEBCAM AT ANTONITO HAS SOME SNOW FALLING...THOUGH MOST IS MELTING ON PAVEMENT SURFACES...AND WITH TEMPERATURES STILL AROUND OR SLIGHTLY ABOVE FREEZING EXPECT THIS TO CONTINUE. HAVE PUT UP A WINTER WEATHER ADVISORY FOR THE LOWER ELEVATIONS OF THE EASTERN SAN JUANS AND LA GARITAS AS WELL AS THE HIGHER AREAS OF THE SAWATCH RANGE. WARNING AREAS COULD PICK UP A TOTAL OF 8 TO 16 INCHES...WITH 4 TO 8 INCHES FOR THE ADVISORY AREAS. THE WESTERN SIDE OF THE SAN LUIS VALLEY COULD SEE ON THE ORDER OF 1 TO 4 INCHES...BUT WARM GROUND MAY LIMIT ACCUMULATIONS TO LESSER AMOUNTS. THE SANGRES AND WETS COULD ALSO PICK UP SOME ADDITIONAL ACCUMULATIONS TONIGHT...WITH ANOTHER 1 TO 3 INCHES FOR THE LOWER ELEVATIONS...AND 2 TO 5 INCHES FOR THE HIGHER PEAKS. SNOW WILL WIND DOWN EARLY TOMORROW MORNING...SO HEADLINES WILL EXPIRE AT 6 AM. MEANWHILE...SOUTHEAST PLAINS WILL SEE A WIDESPREAD FREEZE TONIGHT...AND CURRENT FREEZE WARNING STILL LOOKS ON TRACK. UPPER TROF AXIS WILL SHIFT EAST OF THE AREA ON TUESDAY...BUT WITH LINGER MOISTURE AND INSTABILITY...EXPECT ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS ACROSS THE MOUNTAINS. TEMPERATURES WILL REBOUND A FEW DEGREES OVER THOSE OF TODAY...BUT HIGHER MOUNTAINS WILL STILL SEE PRECIPITATION IN THE FORM OF SNOW. ANY ACCUMULATIONS SHOULD REMAIN LIGHT...WITH A SPOTTY 1-3 INCHES POSSIBLE. -KT .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 340 PM MDT MON MAY 12 2014 TUESDAY NIGHT THROUGH SATURDAY...LONG RANGE MODELS INDICATE THAT THE UPPER SYSTEM WILL PARK OVER THE MIDWEST THROUGH MUCH OF THE WORK WEEK...KEEPING COLORADO UNDER NW FLOW ALOFT. THIS FLOW IS A COOLER ONE...SO THE WARM UP FOR THE FORECAST AREA IS EXPECTED TO BE SLOWER UNTIL THE UPPER PATTERN SHIFTS. THE UPPER RIDGE TO THE WEST IS FORECAST TO FINALLY FLATTEN AND SLIDE ACROSS THE STATE ON SAT. THIS TRANSLATES TO ANOTHER THREAT OF FREEZING TEMPS FOR THE PLAINS TUE NIGHT...THEN HIGH TEMPS ON WED IN THE 50S AND 60S. TEMPS GRADUALLY WARM THU THROUGH SAT WITH MAX TEMPS IN THE 70S FOR THE PLAINS...AND IN THE 60S FOR THE HIGH VALLEYS. EXTENDED MODELS ALSO HINT AT MORE OF A SUMMERTIME PATTERN WHEN IT COMES TO CONVECTION...WITH AN ISOLATED THREAT FOR SHOWERS AND STORMS OVER THE MTS EACH AFTN AND EARLY EVE THROUGH SAT. SUNDAY AND MONDAY...A LARGE UPPER TROUGH OF LOW PRESSURE MOVES ONSHORE ACROSS THE WEST COAST LATE SAT...PRODUCING INCREASING SW FLOW ALOFT FOR THE DESERT SW. LOOK FOR DRY AND VERY WARM CONDITIONS FOR THE FORECAST AREA BOTH SUN AND MON...WITH MAX TEMPS IN THE 80S FOR THE E PLAINS...AND IN THE 60S AND 70S FOR THE HIGH VALLEYS. MOORE && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 340 PM MDT MON MAY 12 2014 VFR CIGS EXPECTED AT KCOS AND KPUB...THOUGH KCOS COULD SEE A BRIEF DIP TO MVFR AS SHOWERS DROP DOWN OUT OF THE NORTH AND CLIP BY THE TERMINAL. NORTH WINDS OFF THE PALMER DIVIDE SHOULD PREVENT FOG FORMATION TOWARDS MORNING...THOUGH SOME MVFR STRATUS WILL BE POSSIBLE AT TIMES TUESDAY MORNING. KALS WILL SEE THE BEST CHANCE FOR SNOW SHOWERS...THOUGH ACCUMULATIONS AT THE TERMINAL SHOULD REMAIN AROUND AN INCH OR LESS...MAINLY ON GRASSY SURFACES. VFR CONDITIONS ARE EXPECTED ALL THREE TERMINALS TUESDAY AFTERNOON. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING FROM MIDNIGHT TONIGHT TO 8 AM MDT TUESDAY FOR COZ083>089-093>099. WINTER WEATHER ADVISORY UNTIL 6 AM MDT TUESDAY FOR COZ060-064- 067. WINTER STORM WARNING UNTIL 6 AM MDT TUESDAY FOR COZ066-068. && $$ SHORT TERM...KT LONG TERM...MOORE AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1217 PM MDT MON MAY 12 2014 .UPDATE... ISSUED AT 1208 PM MDT MON MAY 12 2014 ANOTHER DISTURBANCE COMING DOWN THE BACK SIDE OF THE UPPER TROF WILL KEEP SNOW GOING ALONG THE CONTINENTAL DIVIDE. NAM...GFS...AND RAP ALL SUGGEST WARNING CRITERIA SNOWFALL WILL OCCUR ACROSS THE HIGHER ELEVATIONS OF THE EASTERN SAN JUAN AND LA GARITAS WITH ADVISORY SNOWFALL AMOUNTS FOR THE LOWER ELEVATIONS. THIS SEEMS REASONABLE GIVEN THE FORCING AND INSTABILITY PRESENT. HAVE UPGRADED THE WINTER WEATHER ADVISORIES TO WARNINGS FOR ZONES 66 AND 68...AND HOISTED ADVISORIES FOR THE LOWER ELEVATIONS OF THE EASTERN SAN JUANS AND LA GARITAS...AS WELL AS THE HIGHER ELEVATIONS OF THE SAWATCH RANGE. AS TEMPERATURES DROP INTO THIS EVENING...EXPECT ROADWAYS WILL BECOME SLICK AND SNOW PACKED. WESTERN PORTIONS OF THE SAN LUIS VALLEY COULD PICK UP 1 TO 4 INCHES OF SNOW WITH EASTERLY UPSLOPE FLOW IMPINGING ON THE HIGHER TERRAIN...THOUGH SUSPECT THAT WARM GROUND WILL MELT SOME OF THIS OFF AS IT FALLS THIS AFTERNOON...SO NO HIGHLIGHTS APPEAR NEEDED. ANOTHER WAVE OF MODERATE TO HEAVY SNOW IS CURRENTLY FALLING ACROSS THE EASTERN SLOPES OF THE WETS AND SANGRES THIS AFTERNOON. HIGH RES HRRR WANES THIS OFF PRETTY QUICKLY THROUGH THE EARLY AFTERNOON...SO WILL NOT HOIST ANY HIGHLIGHTS JUST YET...BUT WILL MONITOR THESE AREAS CLOSELY. -KT UPDATE ISSUED AT 905 AM MDT MON MAY 12 2014 ANOTHER BAND OF SNOW IS MOVING INTO NORTHERN EL PASO AND TELLER COUNTIES THIS MORNING. ALTHOUGH ADDITIONAL SNOWFALL AMOUNTS WILL REMAIN LIGHT (1-2 INCHES)...GUSTY WINDS AND POOR VISIBILITIES WILL KEEP TRAVEL CONDITIONS POOR. HAVE OPTED TO ALLOW THE WINTER STORM WARNINGS FOR TELLER AND NORTHERN EL PASO COUNTY TO EXPIRE...BUT HAVE PUT UP A WINTER WEATHER ADVISORY UNTIL NOON TO ACCOUNT FOR CONTINUING SNOWFALL AND POOR VISIBILITY. ALL OTHER HIGHLIGHTS ASIDE FROM THE SOUTHWEST MOUNTAIN WINTER WEATHER ADVISORY...HAVE EXPIRED AT 9 PM. -KT UPDATE ISSUED AT 816 AM MDT MON MAY 12 2014 UPDATED TO TAKE DOWN FREEZE WARNINGS VALID FOR THIS MORNING. HOWEVER...ANOTHER ROUND OF FREEZING TEMPERATURES IS EXPECTED TONIGHT...AND FREEZE WARNINGS ARE ALREADY OUT. -KT && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM MDT MON MAY 12 2014 ...MAIN CONCERNS INCLUDE UNSEASONABLY COLD TEMPS FOR TODAY...FREEZING TEMPS FOR PLAINS TONIGHT...AND SNOWS FOR THE SW MTNS... CURRENTLY... WEATHER SYSTEM THAT HAS BROUGHT BENEFICIAL PRECIP TO THE REGION (ALONG WITH LATE SEASON SNOW) IS GRADUALLY WINDING DOWN OVER A GOOD PART OF THE REGION. MOST PRECIP OVER THE PLAINS IS DECREASING AT 3 AM WITH A SOME PRECIP STILL NOTED GENERALLY N OF HIGHWAY 50. PRECIP WAS STILL OCCURRING OVER THE MTNS AS PER RADAR...SFC OBS AND WEB CAMS. SAT PIX AND MOSAIC RADAR IMGY STILL SHOWS LOW SPINNING OVER THE CO REGION WITH 1 WELL DEFINED VORT CENTER OVER NC CO WHILE THE MAIN LOW WAS STILL BACK OVER THE 4 CORNERS REGION. TODAY... PRECIP OVER THE PLAINS WILL CONTINUE TO DECREASE AND EXPECT MOST IF NOT ALL OF IT TO BE OVER WITH BY MID TO LATE MORNING. ONLY EXCEPTION WILL BE OVER THE PALMER DVD WHERE SHOWERS MAY LINGER INTO EARLY AFTERNOON GIVEN THE STRONG NORTHERLY FLOW. MAIN AREA OF PRECIP WILL BE OVER THE GREATER SAN JUAN REGION. TROUGH IS GOING TO HOLD BACK OVER THIS AREA TODAY AND TONIGHT...AND FLOW AT 700 MB BECOMES EASTERLY OVER THE S CENTRAL CO REGION. THIS FLOW COMBINED WITH FAVORABLE LAPSE RATES AND QG FORCING SHOULD ALLOW FOR SEVERAL MORE INCHES OF SNOW FOR THE HIGHER ELEVATIONS OF THE SAN JUANS...ALONG WITH LOWER ELEVATION RAIN/SNOW SHOWERS. FOR THIS REASON I EXTENDED THE WINTER WX ADVISORIES FOR THE SAN JUAN REGION. IT IS QUITE POSSIBLE THAT WARNING CRITERIA MAY OCCUR GIVEN THE CONVECTIVE NATURE OF THE SNOW THAT WILL OCCUR TODAY. IT IS GOING TO BE QUITE COOL TODAY OVER THE REGION AND MAX TEMPS WILL RANGE 25 TO 30F DEGREES BELOW NORMAL. HIGHS WILL ONLY BE MAINLY IN THE 40S OVER THE PLAINS WITH A 50 OR TWO OVER THE FAR E PLAINS. TEMPS OVER THE PALMER DIVIDE WILL BE IN THE 30S. WE MAY SEE A MINIMUM MAX TEMP RECORD TODAY FOR AREAS OF THE PLAINS. GIVEN THE GUSTY NNW WINDS IT WILL EVEN FEEL COLDER. IN A NUTSHELL...IT WILL FEEL MORE LIKE MARCH THAN MID MAY. DRESS APPROPRIATELY. TONIGHT... FREEZE WARNINGS HAVE BEEN ISSUED FOR THE ENTIRE PLAINS. TEMPS ALONG THE LOWER ARK RVR VALLEY WILL GENERALLY BE AT OR AROUND 32 WITH TEMPS ON THE PALMER DVD AND RATON MESA IN THE 25 TO 30F DEGREE RANGE. SNOW WILL CONTINUE OVER THE SAN JUANS THIS EVENING BUT SHOULD DECREASE IN INTENSITY AND COVERAGE DURING THE EARLY MORNING HOURS AS THE LOW SHIFT EAST-SOUTHEAST INTO THE TX PHDL REGION. OVERALL...WE COULD SEE 4-8 OF ADDITIONAL SNOW FOR THE SAN JUANS TODAY THROUGH TONIGHT. /HODANISH .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 340 AM MDT MON MAY 12 2014 MODELS IN GOOD AGREEMENT THROUGH THE EXTENDED WITH A HIGHLY AMPLIFIED PATTERN ACROSS THE REGION. AN UPPER LEVEL STORM SYSTEM STRETCHING FROM THE NORTHERN PLAINS TO THE DESERT SOUTHWEST WILL BEGIN TO SLOWLY MOVE EASTWARD ON TUESDAY. A DISTURBANCE ALONG THE BACKSIDE OF THE MAIN TROUGH WILL BE TRACKING SOUTH ACROSS THE CONTINENTAL DIVIDE TUESDAY MORNING AND MOVE INTO NEW MEXICO BY TUESDAY AFTERNOON. MODELS ALL HAVE WIDESPREAD LIGHT TO MODERATE SNOWFALL FOR ALL MOUNTAIN AREAS TUESDAY MORNING. THE HEAVIEST SNOW WILL LIKELY FALL OVER THE SAN JUAN RANGE WHERE AN ADDITIONAL 2 TO 4 INCHES OF SNOW ARE EXPECTED. THE CENTRAL AND EASTERN MOUNTAINS WILL LIKELY SEE AN ADDITIONAL 1 TO 3 INCHES ON TUESDAY. ON THE PLAINS...EXPECT DRY AND BREEZY CONDITIONS WITH COOL AFTERNOON HIGHS IN THE 50S. MODELS ALL HAVE PRECIPITATION FOR THE MOUNTAINS COMING TO AN END BY TUESDAY EVENING AS THE UPPER SYSTEM SHIFTS EAST...AND THE DISTURBANCE EMBEDDED IN THE BACKSIDE FLOW IS SOUTH IN NEW MEXICO. OVERNIGHT LOWS TUESDAY NIGHT INTO WEDNESDAY MORNING WILL ONCE AGAIN DROP INTO THE UPPER 20S TO LOWER 30S. THOSE WITH SENSITIVE OUTDOOR PLANTS SHOULD BRING THEM INDOORS. THE PATTERN STALLS ON WEDNESDAY...WITH THE LARGE UPPER LEVEL TROUGH FROM THE GREAT LAKES INTO THE SOUTHERN PLAINS...WHILE AN UPPER LEVEL RIDGE BUILDS ALONG THE WEST COAST. THIS WILL PUT SOUTHERN COLORADO UNDER BROAD AND PERSISTENT NORTHWESTERLY FLOW. PRECIPITATION CHANCES WILL BE HIGHLY DEPENDENT ON EMBEDDED DISTURBANCES IN THE NORTHWEST FLOW THROUGH AT LEAST FRIDAY. PERIODS OF LIGHT SNOW WILL BE POSSIBLE ACROSS THE MOUNTAIN AREAS EACH DAY. AS FOR THE PLAINS...MODELS REMAIN CONSISTENT WITH A DISTURBANCE ON THURSDAY NIGHT INTO FRIDAY WHICH MAY BRING SHOWER ACTIVITY TO AT LEAST THE FAR EASTERN PLAINS. COVERAGE AND CONVECTIVE NATURE ARE HIGHLY UNCERTAIN FOR THE PLAINS AT THIS TIME BUT THE POSSIBILITY IS THERE. TEMPERATURES WILL GRADUALLY WARM WEDNESDAY THROUGH FRIDAY...WITH THE PLAINS REACHING THE 70S BY THURSDAY AND FRIDAY. THE PATTERN WILL BEGIN TO PROGRESS ON SATURDAY AS A STORM SYSTEM OFF THE BRITISH COLUMBIA COAST MOVES ONSHORE. THIS WILL FORCE THE UPPER RIDGE OVER COLORADO. EXPECT DRY CONDITIONS THROUGH THIS PERIOD WITH MUCH WARMER TEMPERATURES. HIGHS ACROSS THE EASTERN PLAINS WILL LIKELY REACH WELL INTO THE 80S WITH A FEW LOW 90S POSSIBLE. MOZLEY && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1141 AM MDT MON MAY 12 2014 CIGS WILL REMAIN MVFR TO VFR THROUGH THE AFTERNOON AT THE TAF SITES...THOUGH THERE IS THE POTENTIAL INTO THIS EVENING FOR KALS TO DROP DOWN INTO THE IFR CATEGORY IN SNOW SHOWERS AND FOG. KCOS WILL ALSO HAVE THE POTENTIAL FOR SOME STRATUS AND FOG TOWARDS MORNING...THOUGH HAVE KEPT CIGS IN THE MVFR RANGE FOR NOW. WINDS WILL REMAIN GUSTY OUT OF THE NORTH AT 20 TO 35 KTS FOR BOTH KCOS AND KPUB THROUGH THE AFTERNOON BEFORE DECREASING OVERNIGHT. WINDS AT KALS WILL REMAIN OUT OF THE EAST AT 10-15 KTS THROUGH THE AFTERNOON. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING FROM MIDNIGHT TONIGHT TO 8 AM MDT TUESDAY FOR COZ083>089-093>099. WINTER WEATHER ADVISORY UNTIL 6 AM MDT TUESDAY FOR COZ060-064- 067. WINTER STORM WARNING UNTIL 6 AM MDT TUESDAY FOR COZ066-068. && $$ UPDATE...KT SHORT TERM...HODANISH LONG TERM...MOZLEY AVIATION...KT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
305 PM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE REMAINS IN CONTROL THROUGH TODAY THEN A BACK DOOR COLD FRONT STARTS MOVING THROUGH THE REGION LATE TONIGHT INTO TUESDAY. MARITIME HIGH PRESSURE WEDNESDAY PROVIDES BELOW AVERAGE TEMPERATURES FOLLOWED BY A PERIOD OF UNSETTLED WEATHER THURSDAY INTO THE WEEKEND. THE BEST CHANCE OF HEAVY RAIN AND POSSIBLE THUNDERSTORMS IS EXPECTED FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 2 PM UPDATE... TEMPS NOW IN THE LOW TO MID 80S AT 2 PM ACROSS THE INTERIOR IN RESPONSE TO DEEP BLYR MIXING WITH SURFACE WINDS WSW UP TO 20-25 MPH. AT THE COAST PGRAD WEAK ENOUGH TO SUPPORT A SSW WIND. HOWEVER TEMPS AT THE SHORE STILL WARM WITH READINGS 75-80! WATCHING AREA OF CLOUD DEVELOPMENT OVER PA WITH NOTICEABLE CYCLONIC SWIRL AS LOW AMPLITUDE SHORT WAVE MOVES ACROSS THIS AREA. THIS SHOWS UP NICELY ON THE SPC MESOANALYSIS ESPECIALLY AT H7. SHOWERS TRYING TO DEVELOP BUT INSTABILITY IS LACKING...BOTH AT THE SURFACE AND ALOFT. DEW PTS ACROSS SOUTHERN NEW ENGLAND REMAIN DRY WITH VALUES IN THE U30S AND L40S. SOME INSTABILITY OVER SOUTHERN NJ THAT MAY ADVECT NORTHEAST INTO NYC/LONG ISLAND. THUS ANY SHOWER ACTIVITY SHOULD SLIDE ACROSS PA/NJ/NYC...PERHAPS CLIPPING SOUTHWEST CT. THEREFORE EXPECTING SOUTHERN NEW ENGLAND TO REMAIN DRY THRU THIS EVENING. PREVIOUS DISCUSSION BELOW. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ANOTHER SPECTACULAR DAY IN PROGRESS WITH DEEP LAYER RIDGE OVER THE EASTERN GREAT LAKES AND SURFACE HIGH SOUTH OF NEW ENGLAND. THIS SETUP IS PROVIDING LARGE SCALE SUBSIDENCE OVER THE REGION ALONG WITH LOW LEVEL WESTERLY FLOW. THUS ABUNDANT SUNSHINE PREVAILS ALONG WITH COMFORTABLE HUMIDITY WITH DEW PTS IN THE 30S AND 40S. UPSTREAM SOUNDING AT ALBANY NY SUPPORTS HIGHS AROUND 80F WITH 850 TEMPS OF +11C. HOWEVER WITH BLYR EXTENDING UP TO 700 MB ALONG WITH WESTERLY BLYR WINDS HIGHS WILL CLIMB INTO THE M80S WITH A LOW PROBABILITY OF A FEW SPOTS BRIEFLY GETTING INTO THE U80S! THUS HAVE INCREASED HIGHS A TAD FROM PREVIOUS FORECAST. THINK DRY WEATHER WILL PREVAIL TODAY DESPITE BACKDOOR FRONT APPROACHING FROM MAINE. PREFRONTAL AIRMASS IS VERY DRY WITH DEW PTS IN THE 30S AND 40S. THIS RESULTS IN VERY LITTLE TO ANY AVAILABLE INSTABILITY. IN ADDITION AS BLYR DEEPENS WINDS BECOME WEST AND LIMIT SURFACE CONVERGENCE. HENCE DRY WEATHER SHOULD PREVAIL THRU SUNSET. THIS IS TYPICALLY THE CASE AHEAD OF BACKDOOR FRONTS. IN ADDITION LATEST HRRR KEEPS SOUTHERN NEW ENGLAND DRY THRU 23Z FOLLOWED BY A FEW POSSIBLE SHOWERS/TSTMS ZIPPING ACROSS WESTERN CT THEREAFTER. HOWEVER THIS IS A VERY LOW PROB. OTHERWISE PREVIOUS FORECAST IN GOOD SHAPE AND NO MAJOR CHANGES PLANNED. && .SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY NIGHT/... TONIGHT...AN APPROACHING WARM FRONT WILL BE STALLED BY A LOW PRESSURE MOVING EAST INTO MAINE. ONCE THIS LOW PRESSURE MOVES QUICKLY EAST...A STRONG HIGH PRESSURE WILL START TO BUILD SOUTH ACROSS NORTHERN NEW ENGLAND. THIS HIGH PRESSURE WILL PUSH A BACK DOOR COLD FRONT INTO SOUTHERN NEW ENGLAND LATE TONIGHT INTO TUESDAY. WILL CONTINUE THE CHANCE FOR SOME SHOWERS INTO PARTS OF OUR REGION TONIGHT...AT LEAST UNTIL THE SUBSIDENCE BECOMES DOMINANT. THERE IS STILL SOME QUESTION AS TO WHEN THIS OCCURS... BUT THE LATEST THINKING IS IT MAY TAKE MOST OF THE NIGHT. COOLER OVERNIGHT TEMPERATURES ARE EXPECTED AS WINDS SHIFT TO THE NORTH AND NORTHEAST BEHIND THE BACK DOOR COLD FRONT. TUESDAY... BACK-DOOR COLD FRONT CONTINUES TO MOVE WEST AS A HIGH PRESSURE BUILDS OVER THE GULF OF MAINE. IT WILL TURN UNSEASONABLY COOL WITH ONSHORE FLOW OFF ROUGHLY UPPER 40S DEGREE WATER. LIKELY TO BE FAIRLY CLOUDY WITH A LONG FETCH OF EASTERLY FLOW UNDERGOING WEAK UPSLOPE AS OVERRUNNING REMAINS PREVALENT ALONG THE LOW- TO MID- LEVEL FRONTAL BOUNDARY SITUATED ACROSS AND TO THE WEST OF NEW ENGLAND. AS SUCH CANNOT COMPLETELY RULE OUT A STRAY SHOWER OR TWO. HOWEVER...EXPECTING MAINLY DRY CONDITIONS. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * DRY WEDNESDAY * UNSETTLED THU INTO WEEKEND WITH POTENTIAL FOR HEAVY RAIN * REMAINING COOL EARLY NEXT WEEK WITH SPOTTY SHOWERS FAIRLY CONFIDENT ON EVOLVING LARGE SCALE PATTERN LATER THIS WEEK AND THROUGH WEEKEND. BUILDING RIDGE OVER WEST COAST LEADS TO DEEPENING FULL LATITUDE TROUGH OVER EASTERN STATES...WHICH EVENTUALLY CLOSES ITSELF OFF OVER GREAT LAKES AS RIDGING PERSISTS ACROSS NORTH ATLANTIC. RESULT IS PERSISTENT S/SE FLOW WHICH WILL LEAD TO PERIODS OF AT LEAST ISOLATED OR SCATTERED SHOWERS. RAINFALL SHOULD BECOME MORE WIDESPREAD AS SLOW MOVING FRONT APPROACHES LATE FRI/SAT...WHEN LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE. WED... UPPER RIDGE BUILDS OVER NEW ENGLAND WHILE HIGH PRESSURE REMAINS OFFSHORE. THIS SHOULD MAINTAIN DRY WEATHER WITH NEAR SEASONABLE TEMPERATURES...ASIDE FROM IMMEDIATE COAST DUE TO ONSHORE FLOW. THU INTO SAT... MAY SEE FEW SHOWERS THU DUE MORE TO PROLONGED S FLOW AS OPPOSED TO SLOW MOVING COLD FRONT WHICH SHOULD STILL BE WELL TO OUR W. COULD BE RATHER WARM/MUGGY DAY THU AS WEAK RIDGING STILL PREVAILS... WHICH MAY ALLOW CLOUDS TO BREAK FOR A TIME. ENSEMBLES AND 12Z MODELS SUGGEST MAIN WINDOW FOR MORE WIDESPREAD SHOWERS/ISOLATED THUNDERSTORMS WILL BE LATE FRI INTO SAT MORNING AS FRONT PUSHES THROUGH. DEEP S FLOW WITH UPPER LOW CLOSING OFF ACROSS GREAT LAKES WILL BRING ANOMALOUSLY MOIST /+2 TO +3 SD/ AIRMASS INTO REGION ALONG WITH FAIRLY POTENT 850 MB JET. EARLY INDICATIONS ARE FOR AS MUCH AS 1 TO 2 INCHES OF RAIN DURING THIS TIME FRAME PER ENSEMBLE PROBABILITIES. SUN AND MON... DESPITE FRONT MOVING OFFSHORE...CLOSED UPPER LOW MEANS COOL/SHOWERY PERIOD MAY BE IN STORE. 12Z GFS IS MOST AGGRESSIVE WITH THIS FEATURE AS IT IS DAMPENED OUT IN ENSEMBLE MEANS. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/...HIGH CONFIDENCE. THRU 00Z...VFR WITH SSW WINDS ALONG THE COAST AND WSW INLAND GUSTING UP TO 20 KT. DRY WEATHER PREVAILS WITH ANY SHOWERS/TSTMS DEVELOPING OVER PA MOVING INTO NJ/NYC/LONG ISLAND AND OFFSHORE. LOW PROBABILITY OF THIS ACTIVITY CLIPPING WESTERN CT. AFTER 00Z...BACKDOOR FRONT FROM MAINE MOVES SOUTHWEST-WARD INTO MA/RI/CT BEGINNING 01Z/02Z FIRST ACROSS NORTHEAST MA AND THEN SOUTHWEST-WARD AS THE EVENING PROGRESSES. FRONT WILL COME THRU DRY WITH ANY SHOWER ACTIVITY ACROSS THE LOWER HUDSON VALLEY OF NY/NYC/LONG ISLAND...POSSIBLY CLIPPING CT. TUE AND TUE NIGHT...VFR WITH MAINLY DRY WEATHER. ANY PRECIP WOULD BE VERY LIGHT IN THE FORM OF SPRINKLES. NE WINDS TUE WITH GUSTS UP TO 20 KT ALONG THE COAST...BECOME SE TUE NIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. S WINDS BECOME SW AS THE AFTERNOON PROGRESSES. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY...HIGH CONFIDENCE. VFR WITH POSSIBLE MVFR CIGS NEAR COAST. THURSDAY...MODERATE CONFIDENCE. MVFR IN SCT SHOWERS. IFR POSSIBLE NEAR COAST IN FOG/DRIZZLE. FRIDAY INTO SATURDAY...MODERATE CONFIDENCE. MVFR/IFR IN MORE WIDESPREAD SHOWERS AND ISOLATED TSTMS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUESDAY. WINDS AND SEAS EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA THROUGH TODAY. WINDS INCREASE AS A BACK DOOR COLD FRONT MOVES FROM NORTHEAST TO SOUTHWEST TONIGHT. SMALL CRAFT ADVISORIES MAY AGAIN BE NECESSARY FOR A TIME TONIGHT INTO TUESDAY...THOUGH SEAS LOOK TO REMAIN BELOW 5 FEET. AT THIS POINT...DO NOT HAVE ENOUGH CONFIDENCE IN REACHING 25 KT GUSTS OR 5 FOOT SEAS TO ISSUE SMALL CRAFT ADVISORIES NOW. IT DOES REMAIN A POSSIBILITY...AND IS SOMETHING FUTURE SHIFTS WILL HAVE TO CONSIDER. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY...HIGH CONFIDENCE. HIGH PRESSURE REMAINS OFFSHORE WITH S/SE FLOW ACROSS WATERS. INCREASING E SWELL BUT SHOULD STAY BELOW SCA. MAY SEE AREAS OF FOG/DRIZZLE LATER IN DAY OR AT NIGHT. THURSDAY INTO SATURDAY...MODERATE CONFIDENCE. PERSISTENT S/SE WINDS SHOULD REMAIN BELOW 25 KT BUT SEAS WILL SLOWLY BUILD THROUGH PERIOD...PROBABLY REACHING 5 TO 8 FT ON OUTER WATERS. AREAS FOG SHOULD PREVAIL ALONG WITH AT LEAST SCATTERED SHOWERS. BETTER CHANCE OF WIDESPREAD SHOWERS/FEW THUNDERSTORMS LATE FRI INTO SAT AS SLOW MOVING COLD FRONT APPROACHES WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/JWD NEAR TERM...NOCERA SHORT TERM...BELK LONG TERM...JWD AVIATION...NOCERA/JWD MARINE...NOCERA/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
206 PM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE REMAINS IN CONTROL THROUGH TODAY THEN A BACK DOOR COLD FRONT STARTS MOVING THROUGH THE REGION LATE TONIGHT INTO TUESDAY. MARITIME HIGH PRESSURE WEDNESDAY PROVIDES BELOW AVERAGE TEMPERATURES FOLLOWED BY A PERIOD OF UNSETTLED WEATHER THURSDAY THROUGH SATURDAY. BEST CHANCE OF HEAVY RAIN AND POSSIBLE THUNDERSTORMS EXPECTED FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 2 PM UPDATE... TEMPS NOW IN THE LOW TO MID 80S AT 2 PM ACROSS THE INTERIOR IN RESPONSE TO DEEP BLYR MIXING WITH SURFACE WINDS WSW UP TO 20-25 MPH. AT THE COAST PGRAD WEAK ENOUGH TO SUPPORT A SSW WIND. HOWEVER TEMPS AT THE SHORE STILL WARM WITH READINGS 75-80! WATCHING AREA OF CLOUD DEVELOPMENT OVER PA WITH NOTICEABLE CYCLONIC SWIRL AS LOW AMPLITUDE SHORT WAVE MOVES ACROSS THIS AREA. THIS SHOWS UP NICELY ON THE SPC MESOANALYSIS ESPECIALLY AT H7. SHOWERS TRYING TO DEVELOP BUT INSTABILITY IS LACKING...BOTH AT THE SURFACE AND ALOFT. DEW PTS ACROSS SOUTHERN NEW ENGLAND REMAIN DRY WITH VALUES IN THE U30S AND L40S. SOME INSTABILITY OVER SOUTHERN NJ THAT MAY ADVECT NORTHEAST INTO NYC/LONG ISLAND. THUS ANY SHOWER ACTIVITY SHOULD SLIDE ACROSS PA/NJ/NYC...PERHAPS CLIPPING SOUTHWEST CT. THEREFORE EXPECTING SOUTHERN NEW ENGLAND TO REMAIN DRY THRU THIS EVENING. PREVIOUS DISCUSSION BELOW. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ANOTHER SPECTACULAR DAY IN PROGRESS WITH DEEP LAYER RIDGE OVER THE EASTERN GREAT LAKES AND SURFACE HIGH SOUTH OF NEW ENGLAND. THIS SETUP IS PROVIDING LARGE SCALE SUBSIDENCE OVER THE REGION ALONG WITH LOW LEVEL WESTERLY FLOW. THUS ABUNDANT SUNSHINE PREVAILS ALONG WITH COMFORTABLE HUMIDITY WITH DEW PTS IN THE 30S AND 40S. UPSTREAM SOUNDING AT ALBANY NY SUPPORTS HIGHS AROUND 80F WITH 850 TEMPS OF +11C. HOWEVER WITH BLYR EXTENDING UP TO 700 MB ALONG WITH WESTERLY BLYR WINDS HIGHS WILL CLIMB INTO THE M80S WITH A LOW PROBABILITY OF A FEW SPOTS BRIEFLY GETTING INTO THE U80S! THUS HAVE INCREASED HIGHS A TAD FROM PREVIOUS FORECAST. THINK DRY WEATHER WILL PREVAIL TODAY DESPITE BACKDOOR FRONT APPROACHING FROM MAINE. PREFRONTAL AIRMASS IS VERY DRY WITH DEW PTS IN THE 30S AND 40S. THIS RESULTS IN VERY LITTLE TO ANY AVAILABLE INSTABILITY. IN ADDITION AS BLYR DEEPENS WINDS BECOME WEST AND LIMIT SURFACE CONVERGENCE. HENCE DRY WEATHER SHOULD PREVAIL THRU SUNSET. THIS IS TYPICALLY THE CASE AHEAD OF BACKDOOR FRONTS. IN ADDITION LATEST HRRR KEEPS SOUTHERN NEW ENGLAND DRY THRU 23Z FOLLOWED BY A FEW POSSIBLE SHOWERS/TSTMS ZIPPING ACROSS WESTERN CT THEREAFTER. HOWEVER THIS IS A VERY LOW PROB. OTHERWISE PREVIOUS FORECAST IN GOOD SHAPE AND NO MAJOR CHANGES PLANNED. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT...AN APPROACHING WARM FRONT WILL BE STALLED BY A LOW PRESSURE MOVING EAST INTO MAINE. ONCE THIS LOW PRESSURE MOVES QUICKLY EAST...A STRONG HIGH PRESSURE WILL START TO BUILD SOUTH ACROSS NORTHERN NEW ENGLAND. THIS HIGH PRESSURE WILL PUSH A BACK DOOR COLD FRONT INTO SOUTHERN NEW ENGLAND LATE TONIGHT INTO TUESDAY. WILL CONTINUE THE CHANCE FOR SOME SHOWERS INTO PARTS OF OUR REGION TONIGHT...AT LEAST UNTIL THE SUBSIDENCE BECOMES DOMINANT. THERE IS STILL SOME QUESTION AS TO WHEN THIS OCCURS... BUT THE LATEST THINKING IS IT MAY TAKE MOST OF THE NIGHT. COOLER OVERNIGHT TEMPERATURES ARE EXPECTED AS WINDS SHIFT TO THE NORTH AND NORTHEAST BEHIND THE BACK DOOR COLD FRONT. TUESDAY... BACK-DOOR COLD FRONT CONTINUES TO MOVE WEST AS A HIGH PRESSURE BUILDS OVER THE GULF OF MAINE. IT WILL TURN UNSEASONABLY COOL WITH ONSHORE FLOW OFF ROUGHLY UPPER 40S DEGREE WATER. LIKELY TO BE FAIRLY CLOUDY WITH A LONG FETCH OF EASTERLY FLOW UNDERGOING WEAK UPSLOPE AS OVERRUNNING REMAINS PREVALENT ALONG THE LOW- TO MID- LEVEL FRONTAL BOUNDARY SITUATED ACROSS AND TO THE WEST OF NEW ENGLAND. AS SUCH CANNOT COMPLETELY RULE OUT A STRAY SHOWER OR TWO. HOWEVER...EXPECTING MAINLY DRY CONDITIONS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * HIGH PRESSURE ON WEDNESDAY WITH UNSEASONABLE TEMPS ALONG E COAST * SEASONABLE TEMPS AND UNSETTLED WEATHER THURSDAY THROUGH THE WEEKEND * POTENTIALLY TURNING CHILLY WITH SHOWERS INTO EARLY NEXT WEEK MODELS AND CONFIDENCE... LATEST 00Z GUIDANCE IS IN AGREEMENT SHOWING A STRONG WEST COAST RIDGE WHICH WILL SUPPORT A BROAD/DEEP TROUGH SETTLING OVER THE ERN HALF OF THE CONUS. CLOSER AT HOME...HIGH PRESSURE WILL BE BUILDING IN THE GULF OF MAINE ON WEDNESDAY ALLOWING FOR DRY WEATHER. AS THE TROUGH MOVES TOWARDS NEW ENGLAND...A NORTH ATLANTIC RIDGE WILL HOLD STEADY...AND EVENTUALLY BLOCKS THE PROGRESSION OF THE TROUGH. A SFC LOW PRES WILL INTENSIFIES OVER THE MID-ATLANTIC AS SEVERAL STRONG SHORTWAVES DIG INTO THE BASE OF THE TROUGH. THAT LOW WILL THEN SLIDE UP THE EAST COAST FRIDAY...AND DRAG A COLD FRONT ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY. STILL A LOT OF TIMING ISSUES WITH THIS FORECAST BUT CONFIDENCE IS INCREASING THAT ASIDE FROM HIT OR MISS SHOWERS IN THE MEDIUM RANGE...THE LONG TERM WILL BE VERY UNSETTLED WITH POSSIBLE HEAVY RAIN/FLOODING ISSUES. SOLUTION SPREAD IS GRADUALLY NARROWING BUT GFS/GEFS ARE CONTINUING LEADING HGT FALLS INTO THE EAST FASTER THAN MOST OTHER GUIDANCE IN THE MID-LATE WEEK TIME FRAME. ALTHOUGH LATEST EC GUIDANCE IS ON THE SLOWER SIDE OF THE ENVELOPE WITH THE CMC ACTUALLY BEING IN THE MIDDLE OF THE SOLUTIONS AND ENSEMBLES. TRENDS AND CONTINUITY OVER MULTIPLE DAYS HAVE BEEN FAVORING SLOWER TIMING AS SUPPORTED BY THE AMPLIFIED NATURE OF THE APPROACHING TROUGH AS WELL AS BLOCKY PATTERN IN THE ATLANTIC...WHICH IS SUPPORTED WITH NAO TRENDING NEGATIVE. THEREFORE TRENDED THIS FORECAST TOWARDS THE ENSEMBLES AS WELL AS WPC. DETAILS... WEDNESDAY... HIGH PRESSURE WILL BUILD IN ACROSS THE GULF OF MAINE KEEPING MOST OF THE REGION DRY. TEMPS WILL BE SEASONABLE EXCEPT ALONG THE EASTERN COASTLINE AS ONSHORE FLOW WILL KEEP THE MARITIME AIR AROUND ON WEDNESDAY. HOWEVER STALLED BOUNDARY ACROSS CENTRAL NY MAY ALLOW FOR SOME ISO SHOWERS ACROSS WESTERN ZONES. THURSDAY INTO SATURDAY... STRONG ATLANTIC RIDGE TO THE EAST WILL SLOW THE PROGRESSION OF THE DIGGING TROUGH AND STALL IT JUST WEST OF THE REGION. HOWEVER BY THURSDAY...THE RIDGE WILL BREAK DOWN TEMPORARILY AS STRONG WESTERN RIDGE PUSHES THE TROUGH TOWARDS THE NORTHEAST. EXPECT SEVERAL WEAK WAVES TO DEVELOP AHEAD OF THIS TROUGH WHICH WILL APPROACH THE AREA. HIT OR MISS SHOWERS/T-STORMS POSSIBLE ON THURSDAY WITH MORE WIDESPREAD RAINFALL ON FRIDAY INTO SATURDAY. ALTHOUGH EXACT TIMING OF EACH WAVE IS STILL UNCERTAIN...IT APPEARS THAT THE BEST CHANCE FOR HIGHER PRECIP LOOKS TO BE FRIDAY NIGHT AS LOW PRESSURE SYSTEM DEVELOPS ALONG THE FRONT. STRONG LLJ AND INCREASING MOISTURE TRANSPORT SUPPORTS THE IDEA OF THE POSSIBILITY OF HEAVY RAINFALL. ESPECIALLY SINCE THE TROUGH IS TAPPING INTO DEEP GULF MOISTURE ALLOWING PWAT VALUES TO BE 3 STANDARD DEVIATIONS AWAY. INCREASING CONFIDENCE THAT HEAVY RAINFALL WILL OCCUR BUT THERE IS STILL SOME UNCERTAINTY ON EXACT TIMING...THEREFORE CONTINUED TO MENTION LIKELY POPS FOR FRIDAY INTO SATURDAY. ALSO A LOW CONFIDENCE ON FLOODING POTENTIAL AS FLASH FLOOD GUIDANCE IS APPROX 3 INCHES FOR MUCH OF THE AREA. IN FACT WPC IS FORECASTING 2.5 INCHES OF QPF. SO IF THIS FRONT STALLS/OR SLOWS DOWN ANY MORE WE MAY SEE SIGNIFICANT RAIN FALL AMOUNTS NEAR FLASH FLOOD GUIDANCE. A SEASONABLE BUT HUMID AIR MASS WILL OVERSPREAD THE REGION WITH SW FLOW TAPPING INTO THE GULF...ADVECTING HIGHER DEWPOINTS AHEAD OF THE TROUGH. FOG IS A POSSIBILITY ON WED NIGHT INTO THURSDAY AND AGAIN ON FRIDAY. HIGHS WILL GENERALLY TOP OFF IN THE UPPER 60S TO MID 70S WITH COOLER CONDITIONS ALONG THE COAST...ESP THE SOUTH COAST DUE TO SOUTHERLY FLOW. SUNDAY AND BEYOND... MODELS DIFFER ON THE TIMING ON THE EXIT OF THE SYSTEM LATE SATURDAY INTO SUNDAY. HAVE LOW CONFIDENCE ON WHEN THE FRONT WILL SWEEP EASTWARD AS A SLIGHT CHANGE IN THE PATH COULD LEAD TO A SIGNIFICANT CHANGE IN THE WEATHER FOR THE WEEKEND. OVERALL IT APPEARS THAT THE STRONG ATLANTIC HIGH PRESSURE WILL STALL THE SYSTEM JUST EAST OF THE REGION ON SUNDAY WITH AN UPPER LEVEL CUT OFF LOW FORMING. THIS LOW WILL KEEP THE REGION SHOWERY AS WELL AS COOLER DUE TO THE COLD CORE LOW WOBBLING OVER THE AREA. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/...HIGH CONFIDENCE. THRU 00Z...VFR WITH SSW WINDS ALONG THE COAST AND WSW INLAND GUSTING UP TO 20 KT. DRY WEATHER PREVAILS WITH ANY SHOWERS/TSTMS DEVELOPING OVER PA MOVING INTO NJ/NYC/LONG ISLAND AND OFFSHORE. LOW PROBABILITY OF THIS ACTIVITY CLIPPING WESTERN CT. AFTER 00Z...BACKDOOR FRONT FROM MAINE MOVES SOUTHWEST-WARD INTO MA/RI/CT BEGINNING 01Z/02Z FIRST ACROSS NORTHEAST MA AND THEN SOUTHWEST-WARD AS THE EVENING PROGRESSES. FRONT WILL COME THRU DRY WITH ANY SHOWER ACTIVITY ACROSS THE LOWER HUDSON VALLEY OF NY/NYC/LONG ISLAND...POSSIBLY CLIPPING CT. TUE AND TUE NIGHT...VFR WITH MAINLY DRY WEATHER. ANY PRECIP WOULD BE VERY LIGHT IN THE FORM OF SPRINKLES. NE WINDS TUE WITH GUSTS UP TO 20 KT ALONG THE COAST...BECOME SE TUE NIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. S WINDS BECOME SW AS THE AFTERNOON PROGRESSES. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY THROUGH FRIDAY... WEDNESDAY...HIGH CONFIDENCE. EASTERLY WINDS. VFR WITH POSSIBLE MVFR CIGS ANTICIPATED. IFR OVERNIGHT IS POSSIBLE AS WINDS SWITCH BACK TO THE SOUTH. THURSDAY INTO FRIDAY...MODERATE CONFIDENCE. VFR FOR THURSDAY. CONDITIONS DETERIORATING FRIDAY TO IFR WITH INCREASING AREAL EXTENT OF SHRA AND POSSIBLE TSRA. SOUTHERLY WINDS ON THURSDAY CONTINUING INTO FRIDAY WITH GUSTS UP AROUND 25-30 KTS POSSIBLE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUESDAY. WINDS AND SEAS EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA THROUGH TODAY. WINDS INCREASE AS A BACK DOOR COLD FRONT MOVES FROM NORTHEAST TO SOUTHWEST TONIGHT. SMALL CRAFT ADVISORIES MAY AGAIN BE NECESSARY FOR A TIME TONIGHT INTO TUESDAY...THOUGH SEAS LOOK TO REMAIN BELOW 5 FEET. AT THIS POINT...DO NOT HAVE ENOUGH CONFIDENCE IN REACHING 25 KT GUSTS OR 5 FOOT SEAS TO ISSUE SMALL CRAFT ADVISORIES NOW. IT DOES REMAIN A POSSIBILITY...AND IS SOMETHING FUTURE SHIFTS WILL HAVE TO CONSIDER. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. HIGH PRESSURE WILL BUILD OVER THE EASTERN WATERS TUESDAY NIGHT AND INTO WEDNESDAY. EXPECT EASTERLY WINDS TO CONTINUE...ALLOWING FOR EASTERLY SWELL TO BUILD. FOG AND DRIZZLE POSSIBLE BY LATE WEDNESDAY AS FLOW SWITCH TO THE SOUTH. SCA MAY BE NEEDED FOR THE PERIOD. THURSDAY INTO FRIDAY...LOW CONFIDENCE. LINGER 5FT SEAS TO START INCREASING THROUGHOUT THE DAY WITH THE POSSIBILITY FOR A FEW SHOWERS ON THURSDAY. CONDITIONS DETERIORATE ON FRIDAY AS FRONT APPROACHES THE WATERS. SEAS AND WINDS WILL BUILD IN RESPONSE AS WELL AS HEAVY DOWNPOURS AND ISO THUNDER. SCA WILL BE NEEDED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...NOCERA SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
147 PM EDT MON MAY 12 2014 .PREV DISCUSSION... UPDATE... /ISSUED 1046 AM EDT MON MAY 12 2014/ HI RES MODELS ARE STILL IN GOOD AGREEMENT WITH ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT THIS AFTERNOON BUT SOME DIFFERENCES IN TIMING. HRRR IS QUICKER WITH INITIALIZATION THAN THE LOCAL WRF...16Z COMPARED TO ABOUT 20Z. OVERALL THE POP FORECAST IS ON TRACK AND DID NOT ADJUST THE SLIGHT CHANCE/CHANCE FOR THIS AFTERNOON. I DID HOWEVER END UP PUSHING BACK THE INITIATION TO 17Z. FORECAST DEW POINTS WERE A LITTLE ON THE LOW SIDE SO INCREASED THEM INTO THE AFTERNOON. 11 SHORT TERM /TODAY THROUGH TUESDAY/... WEAK UPPER-LEVEL RIDGING CONTINUES OVER THE REGION TODAY...THEN BEGINS SHIFTING EAST INTO THE WESTERN ATLANTIC TUESDAY. THE RIDGE DOES NOT APPEAR TO BE DOMINANT ENOUGH TO SHUT OFF ALL CHANCES FOR CONVECTION BUT SHOULD LIMIT COVERAGE TO SCATTERED AT BEST AND DIURNALLY ORIENTED. MID-LEVEL LAPSE RATES AROUND 6DEGC/KM OR LESS KEEP INSTABILITY LIMITED WITH ANY THUNDERSTORMS EXPECTED TO REMAIN BELOW SEVERE LIMITS. FOR EARLY THIS MORNING...LOW-LEVEL MOISTURE AND MOIST SOILS ONCE AGAIN CONTRIBUTING TO AREAS OF FOG WITH PATCHY AREAS OF DENSE FOG. COVERAGE IS LESS THAN YESTERDAY MORNING AND IS EXPECTED TO REMAIN SO THIS MORNING AND IT DOES NOT APPEAR THAT THE AREAL COVERAGE OF VISIBILITIES BELOW 1/4 MILE WOULD BE SUFFICIENT FOR A DENSE FOG ADVISORY. 20 LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... LARGE HIGH AMPLITUDE H5 TROUGH OVER CENTRAL US FCST TO CONTINUE PROGRESSING SLOWLY EASTWARD REST OF THE WEEK. BY 12Z WED...TROUGH AXIS WILL STILL BE CENTERED ALONG 90W LONGITUDE BUT SWLY FLOW ALOFT AND WARM/MOIST ADVECTION AHEAD OF IT WILL INCREASE ACROSS THE SE STATES BRINGING CLOUDS AND SOME SCT SHRA WITH IT. INSTABILITY QUITE HIGH OVER THE CENTRAL STATES. HOWEVER AS THE TROUGH PUSHES EAST EACH DAY...LOW LEVEL FLOW PROGGED TO WEAKEN AND INSTABILITY DECREASES SOME. BY 12Z THURSDAY WHEN THE FRONT ASSOCIATED WITH THE UPPER TROUGH MOVES INTO THE STATE...MLCAPE VALUES ONLY AROUND 250-500 J/KG AND 0-1KM BULK SHEAR ONLY 10-20KTS. COULD ALSO SEE UPSTREAM CONVECTION ALONG THE CENTRAL GULF COAST AGAIN INHIBIT STORM DEVELOPMENT INLAND. DEEP SHEAR PROGGED TO REMAIN QUITE STRONG WITH 0-6KM BULK SHEAR 12Z THUR 40-50KTS...INDICATIVE OF STRONG TEMP GRADIENT ALONG FRONT AS WELL. EVEN WITH STRONG DEEP SHEAR...WITH LACK OF INSTABILITY AND LOW LEVEL SHEAR...SVR STORMS APPEAR UNLIKELY AT THIS TIME. COULD SEE PERIOD OF MDT TO HEAVY RAIN ON THURS...BUT WITH SLOW PROGRESSIVE NATURE OF SYSTEM...APPEARS ANY ONE AREA SHOULD NOT SEE MORE THAN 2 INCHES THROUGH 12Z FRI. AFTER FRONT AND ASSOCD SHORT WAVE PUSH THROUGH...UPPER TROUGH SLOW TO PUSH OUT OF EASTERN CONUS. ANOTHER WAVE IN NW FLOW OVER THE CENTRAL PLAINS PROGGED TO MOVE INTO THE TN VALLEY SAT. QUITE A BIT OF DISCREPANCY BETWEEN MED RANGE MODELS /00Z GFS...ECMWF AND CMC/ ON THIS FEATURE...ECMWF SOMEWHAT SLOWER. WITH DRY AIR MASS EXPECTED AS THIS SECOND WAVE APPROACHES...HAVE BACKED OFF A LITTLE ON POPS. NW FLOW CAN BE TRICKY IN THE WARM SEASON SO WILL NEED TO MONITOR THIS. INSTABILITY PROGGED TO BE LOW BUT NOT ZERO. SNELSON && .AVIATION... 18Z UPDATE... WINDS WILL REMAIN SOUTHERLY THROUGH THIS EVENING AND WILL BE VRB AROUND SOUTH. OVERALL THOUGH...TREND SHOULD BE TOWARDS SSW THIS AFTERNOON AND TRANSITION TO SSE THIS EVENING. POP UP SHOWERS ARE DEVELOPING ACROSS THE AREA. FOR THE MOST PART...AM HANDLING THIS WITH A TEMPO SHRA FOR THE BEST TIMING /18-23Z RANGE/. THERE IS A CHANCE OF TS BUT NOT HIGH ENOUGH AT THIS POINT TO MENTION IN THE TAFS. //ATL CONFIDENCE...18Z UPDATE... LOW CONFIDENCE ON WIND DIRECTION DUE TO VARIABILITY AROUND SOUTH. HIGH CONFIDENCE ON CIGS. HIGH CONFIDENCE ON VSBYS EXCEPT MEDIUM DURING THE MORNING. MEDIUM CONFIDENCE ON SHRA OCCURRING AT THE AIRPORT. 11 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 89 65 88 64 / 30 20 20 20 ATLANTA 87 68 86 66 / 30 20 20 20 BLAIRSVILLE 84 61 83 62 / 30 20 30 20 CARTERSVILLE 87 63 86 65 / 30 20 20 20 COLUMBUS 91 68 90 67 / 30 20 20 10 GAINESVILLE 85 66 84 65 / 30 20 20 20 MACON 90 65 89 65 / 30 20 20 10 ROME 87 63 86 63 / 30 20 30 20 PEACHTREE CITY 89 64 88 63 / 30 20 20 20 VIDALIA 90 67 89 68 / 30 20 20 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...11 LONG TERM....NLISTEMAA AVIATION...11
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
321 PM CDT MON MAY 12 2014 .MESOSCALE DISCUSSION... 150 PM CDT THE OVERALL COVERAGE OF CONVECTION LOOKS TO BE LOW THROUGH MID AFTERNOON. THE MESOSCALE CONVECTIVE SYSTEM /MCS/ THAT TRACKED ACROSS SOUTHERN WISCONSIN EARLIER HAS PLACED AN OUTFLOW BOUNDARY OUT TO ITS SOUTH...WHICH IS LOCATED JUST NORTH OF THE IL/WI STATE LINE. WEAK TO MODERATE CONVERGENCE EXISTS ALONG THIS BOUNDARY THANKS TO THE MODEST SOUTH-SOUTHWEST FLOW WITHIN THE WARM SECTOR. THIS WOULD BE ONE AREA FOR POSSIBLE REDEVELOPMENT WITH STORMS LIKELY MOVING EAST-NORTHEAST IF THEY CAN SPARK. FURTHER TO THE SOUTH...OUTFLOW FROM THE EARLIER MCS ACROSS EASTERN IA HAS PROGRESSED EASTWARD WITH SOME OCCASIONAL MORE AGITATED CU SEEN FROM MORRIS/PERU AREAS SOUTHWESTWARD NEAR PEORIA. OVERALL THOUGH THE CU HAS APPEARED FAIRLY FLAT OVER A LOT OF THE AREA. SO DEVELOPMENT CONFIDENCE ALONG THIS EARLIER OUTFLOW BOUNDARY IS LOW. IT IS LOW CONFIDENCE THAT ANY SEVERE STORMS...AND EVEN POSSIBLY MUCH FOR STORMS ACROSS CHICAGO...WILL DEVELOP OVER A GOOD PORTION OF THE CURRENT WATCH THROUGH 5 PM. WILL CONTINUE THE WATCH LOCALLY HOWEVER BASED ON COLLABORATION WITH SPC AND WFO MKX. CONVECTION IS ALSO POSSIBLE LATE IN THE DAY INTO THE EVE AND AS STORMS IN SEVERE THUNDERSTORM WATCH 150 IN EFFECT IMMEDIATELY TO THE WEST OF THE AREA PROGRESS EAST. THAT COULD POSSIBLY RESULT IN A WATCH SOON AFTER THE CURRENT ONE...NAMELY FOR NORTH CENTRAL ILLINOIS...SO DO NOT WANT TO SEND ANY CONFUSING MESSAGES OF A WATCH CANCELLATION THEN A RE-ISSUANCE. MTF && .DISCUSSION... 244 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES THROUGH THE PERIOD INCLUDING THUNDERSTORM COVERAGE/TIMING THROUGH TUESDAY AFTERNOON ALONG WITH SEVERE/HEAVY RAIN POTENTIAL. THEN TURNING MUCH COLDER MIDWEEK WITH A PERIOD OF SHOWERS/RAIN FROM WEDNESDAY EVENING INTO THURSDAY. CONVECTIVE TRENDS OVER THE NEXT FEW HOURS DISCUSSED IN THE ABOVE/RECENT MESOSCALE DISCUSSION WITH ATTENTION NOW SHIFTING TO THUNDERSTORMS EXTENDING FROM CENTRAL IOWA SOUTH TO TEXAS...AHEAD OF THE SLOWLY ADVANCING COLD FRONT. SHORT TERM GUIDANCE CONTINUES TO SHOW ADDITIONAL ACTIVITY DEVELOPING AHEAD OF THE CURRENT LINE AS IT ALL SLOWLY SHIFTS EAST...WHICH WOULD BRING ACTIVITY INTO THE WESTERN CWA AS SOON AS 23Z-00Z. SEVERE POTENTIAL WOULD BE HIGHEST EARLIER WITH BETTER INSTABILITY BEFORE LOST OF DAYTIME HEATING...THOUGH TEMPS WILL ONLY SLOWLY DROP THROUGH THE 70S THIS EVENING. AS NOTED IN THE PREVIOUS DISCUSSION...DO ANTICIPATE ANOTHER WATCH LATER THIS EVENING BUT HOW FAR EAST AND COVERAGE OF SEVERE POTENTIAL WILL BE TIED TO TIMING. MAIN THREATS WOULD CONTINUE TO BE LARGE HAIL AND DAMAGING WIND GUSTS. PRECIPITABLE WATER VALUES INCREASE TO 1.5 INCHES AND EVEN A BIT HIGHER TONIGHT AND COMBINED WITH DEWPOINTS IN THE UPPER 60S AND EVEN A FEW LOWER 70S...HEAVY RAIN IS LIKELY. WHILE THE INDIVIDUAL STORMS WILL BE MOVING NORTHEAST FAIRLY QUICKLY...THE ENTIRE FRONTAL PROGRESSION EASTWARD WILL BE RELATIVELY SLOW THUS HEAVY RAIN OVER THE SAME AREAS COULD RESULT IN SOME FLOODING POTENTIAL. AND WITH THE HEAVY RAINS IN PARTS OF THE AREA SUNDAY EVENING...INCLUDING THE SOUTHERN SUBURBS AND NORTHWEST INDIANA...ADDITIONAL HEAVY RAIN COULD LEAD TO LOCALIZED FLASH FLOODING. HOWEVER...CONFIDENCE IS SOMEWHAT LOW WITH THE POTENTIAL FOR CONVECTION TO THE SOUTHWEST TO MOVE EAST SOUTH OF THE AREA AND POTENTIALLY CUT OFF STRONGER/HEAVIER PRECIP ACROSS NORTHERN IL. PRECIP PROGRESSION EASTWARD WILL LIKELY SLOW TUESDAY MORNING AS IT SLOWLY ENDS FROM WEST TO EAST BUT COULD CONTINUE INTO THE AFTERNOON ACROSS NORTHWEST INDIANA. TEMP TRENDS WILL ALSO BE TRICKY AS THEY WILL LIKELY FALL OR BECOME STEADY ACROSS THE EASTERN HALF WITH SOME RECOVERY IN THE WEST IN THE AFTERNOON. TEMPS WILL CONTINUE TO FALL INTO THE MID/UPPER 40S FOR LOWS BY WEDNESDAY MORNING AND WHILE THESE ARE CLOSE TO NORMAL FOR MID MAY...IT WILL LIKELY FEEL MUCH COLDER GIVEN THE CURRENT TEMPS AND DEWPOINTS. AS THE UPPER TROUGH DIGS ACROSS THE CENTRAL AND SOUTHERN PLAINS WEDNESDAY INTO WEDNESDAY NIGHT...NEW LOW PRESSURE WILL DEVELOP OVER THE OHIO VALLEY AND LIFT NORTHEAST ACROSS THE CENTRAL OR EASTERN GREAT LAKES REGION ON THURSDAY. WHILE CONFIDENCE IS INCREASING IN THE OVERALL TRENDS WITH THIS SYSTEM...ITS EXACT TRACK COULD STILL HAVE LARGE IMPACTS ON THE SPECIFICS OF THE FORECAST. FIRST...THERE WILL PROBABLY BE A SHARP PRECIP GRADIENT ON THE NORTHWEST SIDE OF THIS SYSTEM...WHICH WILL LIKELY BE ACROSS THE WESTERN CWA. THE CLOSER THE LOW TRACKS TO THE AREA...THE STRONGER THE NORTHERLY WINDS WILL BE...ESPECIALLY ACROSS THE EASTERN CWA. BUT AS CLOUDS AND SHOWERS SPREAD NORTH WEDNESDAY WITH A RATHER COLD/WET WEDNESDAY NIGHT/THURSDAY MORNING. HIGHS WEDNESDAY AND THURSDAY LIKELY ONLY IN THE 50S...THOUGH ANY SUNSHINE ESPECIALLY WESTERN AREAS COULD PUSH TEMPS INTO THE 60S. AS AN UPPER LOW DEVELOPS ACROSS THE NORTHERN LAKES REGION THURSDAY AND SLOWLY DRIFTS EAST THIS WEEKEND...WEAK IMPULSES COULD HELP TRIGGER AFTERNOON SHOWERS ON FRIDAY AND PERHAPS AGAIN ON SATURDAY THOUGH COVERAGE SHOULD BE MAINLY ISOLATED. TEMPERATURES WILL START A SLOW WARMING TREND THROUGH THE 60S THIS WEEKEND AND PERHAPS BACK INTO THE 70S EARLY NEXT WEEK. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SSWLY TO SWLY WINDS TO 25KT THIS AFTERNOON AND EVENING OUTSIDE OF THUNDERSTORMS. * TIMING AND CHANCES OF ADDITIONAL TSRA THIS AFTERNOON AND TONIGHT. * OCNL MVFR CIGS THIS AFTERNOON AND TONIGHT. KREIN //DISCUSSION...UPDATED 18Z... MAIN CONCERN CONTINUES TO BE THE CHANCES FOR THUNDERSTORMS THIS AFTERNOON AND TONIGHT...UNTIL A COLD FRONTAL PASSAGE TOMORROW MORNING. THE ENVIRONMENT OVER THE AREA IS WARM AND MOIST WITH TEMPERATURES IN THE 80S AND DEWPOINTS IN UPPER 60S. OLD OUTFLOW BOUNDARIES FROM EARLIER CONVECTIVE ACTIVITY CAN PROVIDE THE FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT...BUT TIMING IS VERY UNCERTAIN AND RESIDUAL CLOUD COVER MAY BE A LIMITING FACTOR FOR THE NEXT FEW HOURS AS BOTH CI AND LOWER STRATOCU ARE FILTERING TH SUNSHINE. ANTICIPATE THAT CLOUD COVER SHOULD THIN WITH TIME AND IS THE TREND IN THE LATEST SATELLITE IMAGERY...SO THERE WILL BE A CHANCE FOR SCATTERED THUNDERSTORM DEVELOPMENT THROUGH THE AFTERNOON AND EVENING. GIVEN THE TIMING AND COVERAGE UNCERTAINTIES...HAVE BACK OFF TO JUST VCTS MENTION...UNTIL A MORE ORGANIZED FOCUSING MECHANISM BECOMES APPARENT. HAVE MAINTAINED THE PROB30 MENTION FOR THUNDER FOR THE LATE NIGHT TO EARLY MORNING HOURS...IN CONJUNCTION WITH THE APPROACHING COLD FRONT. EXPECT THAT WINDS SHOULD SHIFT TO WESTERLY FOLLOWING THE FROPA...WHILE REMAINING RELATIVELY BRISK AND GUSTY. KREIN //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM TO HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE IN CEILING TRENDS. * LOW CONFIDENCE CONVECTIVE TIMING AND COVERAGE TODAY AND TONIGHT. * MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... * TUESDAY NIGHT...VFR. * WEDNESDAY...SLIGHT CHANCE OF PM SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY AND SUNDAY...DRY/VFR. KJB && .MARINE... 320 PM CDT AREAS OF DENSE FOG CONTINUE TO PERSIST LATE THIS AFTERNOON ACROSS NORTHERN LAKE MICHIGAN PER SHIP OBS AND SURROUNDING SFC COASTAL OBS NORTH OF THE WARM FRONT DRAPED WEST TO EAST ACROSS THE MIDDLE PART OF THE LAKE. THIS WARM FRONT EXTENDS BACK WEST TO LOW PRESSURE OVER E CENTRAL MN / NORTHWEST WI WHICH WILL CONTINUE TO MOVE NORTHEAST TONIGHT. THIS FRONTAL BOUNDARY WILL CONTINUE TO BE A FOCUS FOR SHOWER AND THUNDERSTORM DEVELOPMENT TONIGHT AS WELL. A COLD FRONT ASSOCIATED WITH THE LOW WILL SWEEP WEST TO EAST ACROSS THE LAKE AROUND DAYBREAK TUESDAY SWEEPING OUT THE FOG AND BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS INTO THE MORNING TUESDAY. WINDS OCCASIONALLY EXCEEDING SMALL CRAFT ADVISORY THRESHOLDS WILL CONTINUE INTO THIS EVENING ALONG THE ILLINOIS AND INDIANA SHORELINES. ONGOING CONVECTION HAS DISRUPTED THE WIND FIELD CAUSING AN ONSHORE LAKE BREEZE ESPECIALLY FARTHER NORTH CLOSER TO THE OUTFLOW FROM EARLIER THUNDERSTORMS ACROSS WISCONSIN AND CENTRAL LAKE MICHIGAN. AS THE SOUTHERLY GRADIENT REESTABLISHES ITSELF... NEW SCATTERED THUNDERSTORMS MAY ALSO CAUSE HIGHER WINDS AND WAVES INTO THE EVENING THROUGHOUT THE NEAR SHORE WATERS. ED F && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM MONDAY. DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 1 AM TUESDAY. && $$ 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
  [top] Area Forecast Discussion National Weather Service Lincoln IL 254 PM CDT Mon May 12 2014 .DISCUSSION... ISSUED 252 PM CDT Mon May 12 2014 Warm and rather humid day across the forecast area today, with dew points in the upper 60s to around 70 degrees and temperatures mostly in the 80s. Air mass over our area is uncapped and CAPE`s are from 3500-4000 J/kg in central Illinois, but so far convection in our CWA has been spotty. More widespread showers/storms have been occurring across the Ohio Valley. Main action has been filling in across Iowa and the northwest half of Missouri, along a cold front. SHORT TERM...Tonight through Thursday: Initial forecast concern is on the severe weather potential the next several hours. The individual storms to our west have been moving northeast with the overall area only slowly shifting eastward. The HRRR and NMM high-resolution models have that particular band of storms reaching the Illinois River around 6 to 7 pm and the I-55 corridor around 9 to 10 pm. Surface observations over the area are not showing any meaningful boundary currently present, thus the popcorn nature of the showers/storms so far. Infrared and water vapor imagery showing some anti-cyclonic motion over our CWA, which could be causing enough sinking of the air to keep the showers under control so far. 0-6km shear values expected to remain rather modest in most areas, so am thinking that the storms will remain rather disorganized but briefly severe until the main line gets here. Loss of daytime heating should weaken the line of storms somewhat as it moves through tonight, but CAPE`s remain 1000-2000 J/kg ahead of the front so there will still be some instability to work with. Morning model runs have the front roughly along the Indiana border by midday, with threat of thunder diminishing from west to east through the day. Have kept the dry weather west of I-55 for the afternoon with likely PoP`s across east central and southeast Illinois continuing in the afternoon. Temperatures across the east will be slowly falling in the afternoon behind the front. Long-advertised phasing of upper troughs in the north central and southwest U.S. will try to take place the next couple days, although the models keep them somewhat distinct through mid week. Development of a surface low will take place Tuesday night across the lower Mississippi Valley, and this low will be ejected northeast on the nose of a developing 90-110 knot jet. Dry northeast flow will erode the northern fringes of the rain shield some, so will continue to focus the higher PoP`s on Wednesday across the southeast half of the forecast area. As the surface low moves northeast, a large upper low will develop over the upper Mississippi Valley, so the threat of showers will continue even after the main precipitation shield exits. High temperatures both Wednesday and Thursday only expected to be in the upper 50s to around 60 most areas due to the cooler air aloft and the rain. LONG TERM...Friday through Monday: The cool and showery weather will continue into Friday, before the upper low starts to lift into Ontario and the upper pattern over the U.S. flattens out somewhat. A fast moving wave in the upper flow tracks an area of rain southeast later in the weekend, with the ECMWF model about 12-18 hours faster and a bit further north. Have limited PoP`s on Saturday night and Sunday to slight chances across the south half of the forecast area, but this may need to be bumped up if these trends persist on the next couple model runs. A more substantial warming trend will occur early next week, as ridging occurs across the Plains. Geelhart && .AVIATION... ISSUED 1253 PM CDT Mon May 12 2014 Main aviation concern during the 18z TAF period will be timing of potential convection later this afternoon into tonight. Model solutions are all over the place concerning convective initiation: however, best forcing associated with cold front and other mesoscale boundaries appears that it will stay west of the central Illinois terminals until evening. HRRR tries to develop scattered showers/storms west of I-55 between 20z and 23z, while NAM continues to focus mainly on the evening hours. Will include VCTS at all TAF sites from mid-afternoon on, but will not mention predominant thunder until later. Based on NAM solution, will include TSRA between 00z and 04z at KPIA, then further east to KCMI between 05z and 09z. Once initial line of storms passes, a period of light rain will likely linger along and just behind the cold front overnight into early Tuesday morning. Forecast soundings suggest MVFR ceilings with this precip. Winds will initially be from the S/SW this afternoon, gusting to between 20 and 25kt at times. S/SW winds will continue through the evening before veering to the W/NW after FROPA overnight. Winds will shift to the W/NW at KPIA by 09z, then further east to KCMI by 15z. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1256 PM CDT MON MAY 12 2014 .DISCUSSION... 1056 AM CDT A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR FAR NORTHERN ILLINOIS UNTIL 5 PM THAT COVERS BASICALLY THE INTERSTATE 88 CORRIDOR AND NORTHWARD. THIS INCLUDES ROCKFORD AND THE CITY OF CHICAGO. THE REALLY CHALLENGING FORECAST OF CONVECTIVE EVOLUTION CONTINUES WITH A COUPLE REGIONAL COMPLEXES OF STORMS PROPAGATING EASTWARD AT THE LEADING EDGE OF THE WARM AND MOIST LOW-LEVEL AIR. THE NORTHERN ONE ACROSS SOUTHERN WI IS THE MORE ROBUST ONE AND FEEDING ON BETTER UPPER AND MID-LEVEL SUPPORT. THE STORMS NEAR THE QUAD CITIES HAVE SHOWN A GENERAL WEAKENING TREND. THE ORIENTATION OF DEEP LAYER SHEAR VECTORS TO THESE COMPLEXES DO NOT INDICATE A RAPID WIND THREAT DEVELOPING FROM THESE...HOWEVER THE OVERALL CAPE/SHEAR SPECTRUM IS POTENTIALLY FAVORING SCATTERED SEVERE STORMS TO DEVELOP THROUGH THE AFTERNOON. THE 12Z RAOBS AT DVN AND ILX SOUNDING MODIFIED FOR FORECAST EARLY AFTERNOON TEMPERATURES INDICATED INSTABILITY IN EXCESS OF 2000 J/KG IN THE MIXED LAYER...AND POTENTIALLY TOPPING 3500 J/KG. AS THINNING OF HIGH CLOUDS CONTINUES OVER THE FORECAST AREA...THIS HIGH DEGREE OF DESTABILIZATION SHOULD BE REALIZED. WHILE EXACT EVOLUTION OF THESE COMPLEXES AS IT RELATES TO OUR FORECAST AREA IS UNCERTAIN...AT LEAST SCATTERED CONVECTIVE DEVELOPMENT IS BELIEVED TO BE PROBABLE FROM SURFACE AND/OR ELEVATED OUTFLOW BOUNDARIES OVER FAR NORTHERN ILLINOIS. CONVECTIVE ALLOWING MODELS CERTAINLY VARY IN THEIR SOLUTIONS...BUT GENERALLY HAVE BEEN TRENDING WITH MORE AFTERNOON CONVECTION ACROSS NORTHERN ILLINOIS. SO IT WAS THOUGHT BEST TO INCLUDE FAR NORTHERN ILLINOIS IN THIS SEVERE THUNDERSTORM WATCH THROUGH THIS AFTERNOON. THE PRIMARY HAZARDS WOULD BE WINDS AND LARGE HAIL...WITH MULTI- CELL CLUSTERS THE FAVORED MODE. MTF //PREV DISCUSSION... 328 AM CDT AMONG THIS MORNING`S MANY RECAST CHALLENGES ARE TEMPS TODAY...PRECIP AND CONVECTIVE TRENDS THROUGH TONIGHT...RAIN CHANCES LATER IN THE WEEK WITH SECONDARY CYCLONE...AND MAGNITUDE OF COLD AIR MASS LATER THIS WEEK. IT IS FUNNY HOW OFTEN CONFIDENCE IN A FORECAST DECREASES AS THE FORECAST TIME NEARS. LAST NIGHT AT THIS TIME WAS FAIRLY CONFIDENT THAT CONVECTION TO OUR WEST WOULD DISSIPATE BEFORE MAKING IT INTO OUR AREA WITH THE FOCUS SHIFTING NORTH INTO WISCONSIN...BUT PLAYING A GAME OF METEOROLOGICAL CHICKEN WITH THE MCS OVER IOWA THAT CONTINUES TO CHARGE EAST TOWARD THE MISSISSIPPI RIVER EARLY THIS MORNING AND AM GROWING INCREASINGLY TEMPTED TO FLINCH AND BUMP UP POPS SOME THIS MORNING. THE ATMOSPHERE OVER NORTHERN ILLINOIS WAS SIGNIFICANTLY MODIFIED AND STABILIZED BY SUNDAY EVENING`S CONVECTION...BUT CONTRASTING THE 00Z SOUNDINGS FROM DVN AND ILX SHOW JUST HOW NEARBY THE CONVECTIVELY MOIST AND UNSTABLE AIR MASS LIES. THE COMPOSITE SECONDARY WARM FRONT/OUTFLOW BOUNDARY EXTENDING ROUGHLY FROM KLAF TO JUST SOUTH OF THE QUAD CITIES IS LIFTING NORTH AND/OR WASHING OUT WITH WINDS ACROSS NORTHERN ILLINOIS VEERING MORE SOUTHERLY AND HIGHER DEWPOINTS CREEPING NORTHWARD. SHORT RANGE GUIDANCE IS STRONGLY DIVIDED IN THE HANDLING OF THE MCS OVER IOWA...WITH ONE CAMP SHOWING A FAIRLY RAPID DEMISE OVER THE NEXT SEVERAL HOURS WITH ONLY SCTD SHRA/ISOLD TSRA POTENTIALLY MAKING IT INTO NW CWA WHILE ANOTHER CAMP OF MODELS IS MORE AGGRESSIVE IN BRINGING STORMS EAST ACROSS THE CWA THROUGH THE MORNING. THE IMPLICATIONS OF HOW THIS SCENARIO EVOLVES ARE HUGE FOR TEMPS...WINDS...AND SUBSEQUENT CONVECTIVE CHANCES WITH THE COLD FRONT. CONFIDENCE IS NOT HIGH...BUT LEANING TOWARD STAYING THE COURSE WITH THINKING FROM PREVIOUS FORECASTS WHICH SUGGEST A QUICK WEAKENING TREND WITHOUT MUCH CONVECTION MAKING IT FAR INTO OUR CWA. RECENT REGIONAL RADAR AND SATELLITE TRENDS SEEM TO FINALLY BE SUPPORTING THIS LINE OF THINKING WITH CLOUD TOPS BEGINNING TO QUICKLY WARM WITH DECREASING COVERAGE AND INTENSITY OF THE STORMS. SEVERAL MODELS ARE HINTING AT THE POTENTIAL FOR ADDITIONAL SCTD CONVECTION DEVELOPING IN THE WARM/MOIST/UNSTABLE AXIS EXTENDING FROM DOWNSTATE IL NNE INTO NNW INDIANA. DESPITE LEANING TOWARD THE DRIER SOLUTIONS FOR TODAY WILL BE MAINTAINING CHANCE POPS ACROSS THE CWA TO ALLOW FOR EITHER THE IOWA MCS PERSISTING LONGER AND/OR MOIST/UNSTABLE AXIS THIS AFTERNOON. HIGH TEMPS AND EVEN GUSTINESS OF THE WINDS TODAY WILL HINGE ON CLOUD COVER AND PRECIP. IF THE MCS CONTINUES TO QUICKLY WEAKEN AND DEBRIS CLOUDINESS DISSIPATE...THEN IT SHOULD ALLOW FOR PARTIAL SUNSHINE AND WHICH COULD SEND TIMES CLIMBING WELL INTO THE 80S AND ABOVE OBJECTIVE GUIDANCE. THIS IS THE CURRENT FORECAST AND RATHER THAN FLIP ONLY TO HAVE THE DAY SHIFT HAVE TO FLOP WILL STAY THE COURSE WITH ABOVE GUIDANCE HIGHS AND IF IT BECOMES CLEAR THAT CLOUDS WILL STICK AROUND THE DAY SHIFT CAN BACK OFF ON TEMPS WITH A MORNING UPDATE. THERE ARE A HANDFUL OF CONVECTIVE ALLOWING MODELS SHOWING A RELATIVE MIN IN CONVECTIVE REDEVELOPMENT OVER IOWA TONIGHT FOLLOWING THE STABILIZING EFFECTS OF CURRENT MCS...BUT WITH GREATER NUMBER OF MODELS SUPPORTING RE-DEVELOPMENT PLAN TO HANG ON TO LIKELY POPS TONIGHT AS THE FRONT MOVES EAST TOWARD THE AREA. MORE MARGINAL AND UNIDIRECTIONAL SHEAR PROFILES AND DECREASING INSTABILITY AT NIGHT BOTH WOULD ARGUE FOR STORMS MOVING INTO THE AREA TONIGHT TO BE IN A WEAKENING PHASE WITH SEVERE THREAT DECREASING WITH TIME AND EASTWARD EXTENT TONIGHT. RAIN COULD LINGER INTO TUESDAY...ESPECIALLY IN THE MORNING AND OVER THE EASTERN CWA BEFORE BETTER FORCING PUSHES OFF TO THE EAST AND DRIER AIR MOVES IN. TUESDAY AFTERNOON COULD BE SALVAGEABLE FOR MANY AREAS WITH NEAR NORMAL HIGHS AND LIKELY AN END TO THE PRECIPITATION. LATER WEDNESDAY INTO THURSDAY GUIDANCE REALLY RUNS THE GAMUT IN HANDLING OF THE SECONDARY SHORTWAVE TROUGH ROUNDING THE BASE OF THE DEEP UPPER TROUGH THAT WILL BECOME ESTABLISHED OVER EASTERN NOAM. WPC PREFERRED MODEL CHOICE WAS THE 00Z ECMWF WHICH IS CLOSE TO THE MIDDLE OF THE ROAD OF POSSIBLE SOLUTIONS AND SAW NO REASON TO DEVIATE FROM THIS LINE OF THINKING. ASSUMING THE ECMWF VERIFIES A SECONDARY WAVE OF LOW PRESSURE WILL TRACK NORTHEAST ALONG THE PASSING COLD FRONT AND PRODUCE A PERIOD OF RAIN/SHOWERS...MAINLY SOUTHEASTERN HALF OF THE CWA. REMARKABLY SOME GUIDANCE HAS 850MB TEMPS DROPPING TO 0 TO -2C DURING THE PRECIP WHICH WHILE COLD IS PROBABLY NOT COLD ENOUGH FOR ANY MIXED PRECIP GIVEN THE TIME YEAR BUT PERILOUSLY CLOSE. GIVEN THE MODEL SPREAD EARLY IN THE PERIOD PROBABLY NOT SURPRISING THAT THERE IS SUBSTANTIAL SPREAD IN THE INTENSITY OF THE UPPER TROUGH/LOW LATE IN THE WEEK AND SUBSEQUENT TEMPS WITH FAR MORE AMPLIFIED AND COLD SOLUTION IN THE ECMWF SUPPORTIVE OF TEMPS COLDER THAN WHAT OUR CURRENT FORECAST BUT WITH SO MUCH UNCERTAINTY SO NO REASON TO STRAY FROM THE BLENDED MODEL CONSENSUS. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SSWLY TO SWLY WINDS TO 25KT THIS AFTERNOON AND EVENING OUTSIDE OF THUNDERSTORMS. * TIMING AND CHANCES OF ADDITIONAL TSRA THIS AFTERNOON TONIGHT. * OCNL MVFR CIGS THIS AFTERNOON AND TONIGHT. KREIN //DISCUSSION...UPDATED 18Z... MAIN CONCERN CONTINUES TO BE THE CHANCES FOR THUNDERSTORMS THIS AFTERNOON AND TONIGHT...UNTIL A COLD FRONTAL PASSAGE TOMORROW MORNING. THE ENVIRONMENT OVER THE AREA IS WARM AND MOIST WITH TEMPERATURES IN THE 80S AND DEWPOINTS IN UPPER 60S. OLD OUTFLOW BOUNDARIES FROM EARLIER CONVECTIVE ACTIVITY CAN PROVIDE THE FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT...BUT TIMING IS VERY UNCERTAIN AND RESIDUAL CLOUD COVER MAY BE A LIMITING FACTOR FOR THE NEXT FEW HOURS AS BOTH CI AND LOWER STRATOCU ARE FILTERING TH SUNSHINE. ANTICIPATE THAT CLOUD COVER SHOULD THIN WITH TIME AND IS THE TREND IN THE LATEST SATELLITE IMAGERY...SO THERE WILL BE A CHANCE FOR SCATTERED THUNDERSTORM DEVELOPMENT THROUGH THE AFTERNOON AND EVENING. GIVEN THE TIMING AND COVERAGE UNCERTAINTIES...HAVE BACK OFF TO JUST VCTS MENTION...UNTIL A MORE ORGANIZED FOCUSING MECHANISM BECOMES APPARENT. HAVE MAINTAINED THE PROB30 MENTION FOR THUNDER FOR THE LATE NIGHT TO EARLY MORNING HOURS...IN CONJUNCTION WITH THE APPROACHING COLD FRONT. EXPECT THAT WINDS SHOULD SHIFT TO WESTERLY FOLLOWING THE FROPA...WHILE REMAINING RELATIVELY BRISK AND GUSTY. KREIN //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM TO HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE IN CEILING TRENDS. * LOW CONFIDENCE CONVECTIVE TIMING AND COVERAGE TODAY AND TONIGHT. * MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... * TUESDAY NIGHT...VFR. * WEDNESDAY...SLIGHT CHANCE OF PM SHRA. * THURSDAY...CHANCE OF SHRA. * FRIDAY...SLIGHT CHANCE OF SHRA. * SATURDAY AND SUNDAY...DRY/VFR. KJB && .MARINE... 323 AM CDT AN AREA OF LOW PRESSURE ACROSS THE MID MISSOURI VALLEY EARLY THIS MORNING WILL TRACK NORTHEASTWARD TOWARDS LAKE SUPERIOR BY TONIGHT. AS THIS OCCURS...AN ASSOCIATED WARM FRONT IS EXPECTED TO LIFT NORTHWARD UP THE LAKE THROUGH TONIGHT. AREAS OF FOG...POTENTIALLY DENSE WILL BE LIKELY ACROSS PORTIONS OF THE LAKE TODAY AND TONIGHT AS THIS FRONT...AND THE ACCOMPANYING VERY MOIST AIR MASS MOVES OVER THE COOL LAKE WATERS. A MARINE DENSE FOG ADVISORY MAY BE NEEDED. THE OTHER CONCERN WILL BE THE WINDS TODAY AND TONIGHT WITH THIS WARM FRONT LIFTING UP THE LAKE. THE WINDS SOUTH OF THIS WARM FRONT WILL BECOME SOUTHERLY AROUND 25 KT TODAY...WHILE NORTH OF THE WARM FRONT...SOME STOUT EASTERLY WINDS WILL BE LIKELY. THESE GUSTY SOUTHERLY WINDS WILL RESULT IN LIKELY RESULT IN NEAR SMALL CRAFT ADVISORY WINDS OVER THE ILLINOIS AND INDIANA NEAR SHORE WATERS BY MIDDAY. HOWEVER...IN SPITE OF THIS...I HAVE OPTED TO HOLD OFF ON AN ADVISORY DUE TO THERE BEING SOME QUESTION AS TO EXACTLY HOW STRONG THE WINDS WILL BE OVER THE NEAR SHORE WATERS. IN ADDITION...WITH THE OFFSHORE COMPONENT...WAVES WILL LIKELY NOT BUILD OVER 4 FT IN THE NEAR SHORE WATERS. THE POTENTIAL IS CERTAINLY THERE FOR 25+ KT OFFSHORE FLOW TODAY...WITH THE POTENTIAL NEED FOR AN UPGRADE TO A SMALL CRAFT ADVISORY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM MONDAY. DENSE FOG ADVISORY...LMZ567-LMZ669-LMZ671-LMZ868-LMZ870-LMZ872 UNTIL 3 PM MONDAY. DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 1 AM TUESDAY. && $$ 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 National Weather Service Lincoln IL 1253 PM CDT Mon May 12 2014 .DISCUSSION... ISSUED 949 AM CDT Mon May 12 2014 Another warm and humid day is unfolding across central Illinois, as 14z/9am temps have already risen well into the 70s. The area remains convection-free for the time being, but as weak capping is broken over the next couple of hours widely scattered thunderstorms will begin to develop. Enhanced Cu field is currently evident on visible satellite imagery from Arkansas northeastward across the eastern half of the KILX CWA. Latest mesoanalysis from SPC indicates deep layer moisture convergence maximized from southeast Missouri into southeast Illinois, where HRRR shows scattered thunderstorm development between now and 18z. Elsewhere around central Illinois, convection will likely remain more isolated in nature until later this afternoon when cold front begins to approach from the west. Front is still progged to reach the area after dark tonight, so best chances for widespread convection will likely hold off until late afternoon/early evening in the Illinois River Valley, then further east across the remainder of the area overnight. Barnes && .AVIATION... ISSUED 1253 PM CDT Mon May 12 2014 Main aviation concern during the 18z TAF period will be timing of potential convection later this afternoon into tonight. Model solutions are all over the place concerning convective initiation: however, best forcing associated with cold front and other mesoscale boundaries appears that it will stay west of the central Illinois terminals until evening. HRRR tries to develop scattered showers/storms west of I-55 between 20z and 23z, while NAM continues to focus mainly on the evening hours. Will include VCTS at all TAF sites from mid-afternoon on, but will not mention predominant thunder until later. Based on NAM solution, will include TSRA between 00z and 04z at KPIA, then further east to KCMI between 05z and 09z. Once initial line of storms passes, a period of light rain will likely linger along and just behind the cold front overnight into early Tuesday morning. Forecast soundings suggest MVFR ceilings with this precip. Winds will initially be from the S/SW this afternoon, gusting to between 20 and 25kt at times. S/SW winds will continue through the evening before veering to the W/NW after FROPA overnight. Winds will shift to the W/NW at KPIA by 09z, then further east to KCMI by 15z. Barnes && .PREV DISCUSSION... ISSUED 330 AM CDT Mon May 12 2014 SHORT TERM...Today through Wednesday night Quiet conditions temporarily returned to central and southeast IL early this morning as convection with MCS had shifted east of IL into east central IN and Ohio, and a larger area of convection with a couple MCSS was over WI/IA and eastern KS into far nw MO. Cold front over western IA and eastern KS into central OK and west Texas while warm front was over northern IL. Moist dewpoints in the upper 60s over central and southern IL and mild temps 69-75F with sse winds in warm sector. Strong upper level trof over the Rockies with 557 dm 500 mb low over western CO to eject surface 1002 mb low over east central KS ne into the upper MS river valley by midnight tonight and swing a cold front east across IL overnight. 00Z models are in fair agreement with timing of this cold frontal passage. Isolated to scattered thunderstorms to develop during today especially this afternoon over the IL river valley as air mass destabilizes with CAPES increasing to 1500-2500 J/kg. Best chances of convection will be tonight with slight chance of severe storms nw of IL river this evening. Best risk of severe supercells with possible tornados form mid afternoon into mid evening will be over eastern IA northern MO into far nw IL and sw WI where stronger wind shear will be. Another very warm and humid day with highs in the mid 80s with a few areas se of IL river even seeing upper 80s with enough sunshine. Cold front to pass east into Indiana early Tue morning and have highest chances of convection over eastern IL Tue morning and diminishing to the west. SPC has 5% risk of severe storms Tue from Wabash river east so mostly over IN. Highs Tue range from mid 60s from I-55 west to the low to mid 70s east of I-57 in eastern IL. Looks like a lull in shower chances over central IL Tue night though kept chances of showers over southern areas especially se IL closer to frontal boundary stalling just se of IL. Leaned on wetter ECMWF and NAM models with surface low ejecting ne Wed and passing just se of IL while GFS appears too weak and far to the east with its QPF fields. Have isolated thunderstorms Wed se of I-70 while SPC keeps slight risk of severe storms se of IL Wed. Showers to diminish from the west during Wed night with highest chances near the IN border Wed evening. Cooler highs in the upper 50s and lower 60s Wed and these cooler readings to linger Thu. LONG TERM...Thursday through Monday Medium to long range models and their ensembles continues to advertise large upper level trof over the MS river valley Thu and upper level low lifting north of the Great Lakes this weekend while trof shifts east into the eastern states. As core of coolest 850 mb air shifts ne of central IL during the weekend with upper level low, expect temperatures to modify during this weekend into early next week but generally still stay a below normal. Cool nights in the low to mid 40s Thu night through Sat night. Instability light rain showers possible Thu & Fri especially during the afternoon and early evening with disturbances pivoting thru the nearby upper level trof. Isolated light showers still possible Sat sw of I-74 while dry conditions then prevail from Sat night through Monday. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
102 PM CDT MON MAY 12 2014 .SHORT TERM /TODAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 TWO PROBLEMS TODAY ARE BOTH WITH CONVECTION THE EARLY MORNING CONVECTION WILL BE AN ISSUE WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL MOVING INTO ALREADY SATURATED AREAS. THIS IS ASSOCIATED WITH A WEAK WAVE IN THE FLOW THAT IS LIFTING NORTHEAST ACROSS THE STATE. ADDITIONAL DEVELOPMENT IS LIKELY OVER THE SOUTHEAST HALF OF THE STATE WITH THE COLD FRONT PROGRESSING EAST. THE HRRR HAS WHAT SEEMS TO BE A REASONABLE HANDLE ON THIS. SEVERITY WILL DEPEND ON HOW MUCH RECOVERY WE CAN ACHIEVE AFTER THE MORNING CONVECTION. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 321 AM CDT MON MAY 12 2014 PRECIPITATION WILL MOVE OUT OF THE STATE BY 06Z AS THE PATTERN CHANGES FROM A SOUTHWEST FLOW TO A NORTHWEST FLOW. CANADIAN HIGH PRESSURE WILL DOMINATE THE WEEKS WEATHER WITH TEMPERATURES WELL BELOW NORMAL. WILL POTENTIAL NEED TO CONSIDER SOME FROST WORDING LATER IN THE WEEK, BUT CERTAINTY IS NOT THERE AT THIS TIME BECAUSE OF THE POTENTIAL FOR SOME CLOUD COVER. IT WILL LIKELY TAKE UNTIL THE WEEKEND BEFORE THE COOL HIGH PRESSURE MOVES OFF TO THE EAST. WARMING AND AN INCREASED CHANCE FOR THUNDERSTORMS IS EXPECTED LATER IN THE WEEKEND. && .AVIATION...12/18Z ISSUED AT 102 PM CDT MON MAY 12 2014 UNSETTLED WEATHER EXPECTED THRU THE TAF PD AS A SFC COLD FRONT SWEEPS THRU THE RGN. SHRA/TSRA POSSIBLE THRU THIS EVE AT THE KOTM...KDSM AND KALO TERMINALS. IFR/MVFR CIGS FILL IN BEHIND THE FROPA. IFR/MVFR CIGS EXPECTED TO LIFT BY 15Z TUE. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MS MAY 14 LONG TERM...MS MAY 14 AVIATION...ZOGG
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
318 PM CDT MON MAY 12 2014 .DISCUSSION... SIGNIFICANT HEAVY RAINFALL EVENT IS IN ITS BEGINNING STAGES ACROSS CENTRAL AND N TX THIS AFTN PER REGIONAL MOSAIC RADAR IMAGERY. MODELS ARE IN GOOD AGREEMENT THAT THIS EVENT WILL CONTINUE TO UNFOLD AS THE FRONT PUSHES EWD INTO OUR REGION THIS EVENING/TONIGHT. THE HEAVIEST RAINFALL IS EXPECTED TO FALL DURING THE OVERNIGHT HOURS...BEFORE THE FRONT OUTRUNS THE UPPER LEVEL SUPPORT. TRAINING OF STORMS...ESPECIALLY OVER AREAS THAT HAVE SEEN SIGNIFICANT RAINFALL WITHIN THE LAST 7 DAYS WILL BRING THE THREAT OF FLASH FLOODING TO MUCH OF E TX/SE OK/SW AR. IT APPEARS THAT THIS THREAT MAY BEGIN EARLIER THAN ANTICIPATED...SO HAVE PUSHED THE START TIME OF THE FLASH FLOOD WATCH UP TO 7 PM THIS EVENING. THE HEAVIEST RAINFALL IS EXPECTED TO FALL DURING THE OVERNIGHT HOURS...BEFORE THE FRONT OUTRUNS THE UPPER LEVEL SUPPORT. LIFT WILL BECOME MORE ISENTROPIC AS WE LOSE THE SFC FORCING DURING THE DAY TUESDAY... WHICH WILL LIKELY RESULT IN DECREASING RAIN RATES. DESPITE THIS... A CONTINUING THREAT FOR FLASH FLOODING MAY BE SEEN DUE TO THE OVERNIGHT RAINS...AND THE WATCH MAY NEED TO BE EXTENDED INTO WEDNESDAY. MODELS CONTINUE TO BE IN RESPECTABLE AGREEMENT WITH REGARD TO QPF...PAINTING A WIDESPREAD 3-5 INCHES /WITH HIGHER ISOLD TOTALS LIKELY/ ACROSS THE WATCH AREA...TAPERING OFF SIGNIFICANTLY TO THE SE. RAIN IS EXPECTED TO FINALLY COME TO AN END WEDNESDAY AFTERNOON/NIGHT...AS THE BASE OF THE UPPER TROF MOVES OVERHEAD. UNSEASONABLY COOL TEMPERATURES ARE STILL EXPECTED TUESDAY THROUGH THURSDAY AS NW FLOW ALOFT AND A COOL AIRMASS LINGER OVER THE REGION. MODELS CONTINUE TO TOY WITH A BACK-DOOR COLD FRONT DROPPING INTO OUR EXTREME N DURING FRI/SAT...WITH POSSIBLY SOME LIGHT PRECIP OVER THE NRN HALF OF OUR REGION. BOTH THE GFS AND EURO STALL THE FRONT TO OUR N...SO TEMPS ARE EXPECTED TO GRADUALLY WARM THROUGH THE WEEKEND. /12/ && .PREV DISCUSSION... /ISSUED 1229 PM CDT MON MAY 12 2014/ AVIATION... OBSERVED SOUNDING THIS MORNING FROM SHV SHOWED A NEARLY SATURATED SOUNDING TO NEAR 10KFT AND STRONG LOW LEVEL WINDS IN EXCESS OF 30KTS IN THE LOWEST 5KFT. LATE MORNING/EARLY AFTERNOON HEATING AND A WEAKLY CAPPED ENVIRONMENT HAS RESULTED IN THE DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN AND AROUND THE TERMINALS THIS AFTERNOON. CURRENTLY CEILINGS RANGE FROM NEAR 3KFT TO NEAR 6KFT BUT EXPECT BRIEF MVFR CONDITIONS WITH BOTH CEILINGS AND VSBYS IF AND WHEN ANY CONVECTION MOVES OVER A TERMINAL LOCATION. A STRONG PRESSURE GRADIENT WILL KEEP SSE WINDS SUSTAINED NEAR 10-12KTS WITH HIGHER GUSTS THROUGH THE EARLY EVENING HOURS. LATEST HRRR PROGS SHOW THIS SCATTERED ACTIVITY CONTINUING THROUGH THE AFTERNOON WITH MORE OF A SOLID LINE OF CONVECTION MOVING EASTWARD FROM N CENTRAL TEXAS/CENTRAL OK LATER THIS EVENING ALONG AND AHEAD OF A STRONG COLD FRONT. HANDLED THE SCATTERED AFTERNOON CONVECTION WITH VCTS WITH TEMPO GROUPS BUT PREVAILED TSRA DURING THE EVENING AND OVERNIGHT HOURS ACROSS ALL BUT OUR EASTERN MOST TERMINAL LOCATIONS BASED ON THE HRRR PROGRESSION ON THE CONVECTIVE LINE. /13/ && .PRELIMINARY POINT TEMPS/POPS... SHV 67 72 56 67 48 / 90 70 60 60 10 MLU 68 82 62 70 48 / 30 60 50 60 10 DEQ 59 65 52 65 40 / 100 60 60 50 10 TXK 60 66 54 64 46 / 100 70 60 60 10 ELD 66 72 55 65 43 / 70 70 50 60 10 TYR 60 64 53 67 46 / 100 60 60 30 10 GGG 62 67 54 66 45 / 100 70 60 30 10 LFK 69 73 56 69 47 / 80 70 50 40 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: ARZ050-051-059>061-070>072. LA...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: LAZ001>003. OK...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: OKZ077. TX...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138-149>151. && $$ 12
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1229 PM CDT MON MAY 12 2014 .AVIATION... OBSERVED SOUNDING THIS MORNING FROM SHV SHOWED A NEARLY SATURATED SOUNDING TO NEAR 10KFT AND STRONG LOW LEVEL WINDS IN EXCESS OF 30KTS IN THE LOWEST 5KFT. LATE MORNING/EARLY AFTERNOON HEATING AND A WEAKLY CAPPED ENVIRONMENT HAS RESULTED IN THE DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN AND AROUND THE TERMINALS THIS AFTERNOON. CURRENTLY CEILINGS RANGE FROM NEAR 3KFT TO NEAR 6KFT BUT EXPECT BRIEF MVFR CONDITIONS WITH BOTH CEILINGS AND VSBYS IF AND WHEN ANY CONVECTION MOVES OVER A TERMINAL LOCATION. A STRONG PRESSURE GRADIENT WILL KEEP SSE WINDS SUSTAINED NEAR 10-12KTS WITH HIGHER GUSTS THROUGH THE EARLY EVENING HOURS. LATEST HRRR PROGS SHOW THIS SCATTERED ACTIVITY CONTINUING THROUGH THE AFTERNOON WITH MORE OF A SOLID LINE OF CONVECTION MOVING EASTWARD FROM N CENTRAL TEXAS/CENTRAL OK LATER THIS EVENING ALONG AND AHEAD OF A STRONG COLD FRONT. HANDLED THE SCATTERED AFTERNOON CONVECTION WITH VCTS WITH TEMPO GROUPS BUT PREVAILED TSRA DURING THE EVENING AND OVERNIGHT HOURS ACROSS ALL BUT OUR EASTERN MOST TERMINAL LOCATIONS BASED ON THE HRRR PROGRESSION ON THE CONVECTIVE LINE. && .PREV DISCUSSION... /ISSUED 1055 AM CDT MON MAY 12 2014/ DISCUSSION... WIDELY SCATTERED SHWRS/TSTMS ONGOING THIS MORNING...MOSTLY ASSOCIATED WITH A WEAK PIECE OF ENERGY /BARELY VISIBLE IN WV IMAGERY/ MOVING SEWD ACROSS E TX. SCATTERED CONVECTION WILL CONTINUE TO DEVELOP WITH HEATING...BEFORE THE BIG SHOW BEGINS LATE THIS AFTERNOON/EARLY THIS EVENING WITH THE APPROACH OF THE FRONT. THE FRONT IS CURRENTLY ALONG A ABILENE/WICHITA FALLS/STILLWATER LINE AND MAKING SIGNIFICANT EWD PROGRESS. THAT SAID...CURRENT TEMP/POP FCST IS ON-TRACK...SO NO CHANGES TO THESE MAJOR FCST ELEMENTS ARE EXPECTED. WIND-WISE...WIND SPEEDS ARE RUNNING SIGNIFICANTLY LOWER THAN PREVIOUSLY ANTICIPATED...AND WELL BELOW LAKE WIND ADVISORY CRITERIA. HAVE GONE AHEAD AND MADE THE NECESSARY ADJUSTMENTS TO THE WIND GRIDS AND DROPPED THE ADVISORY. /12/ && .PRELIMINARY POINT TEMPS/POPS... SHV 68 70 56 66 49 / 70 70 60 50 10 MLU 67 80 62 69 48 / 50 60 60 60 20 DEQ 59 65 52 64 41 / 90 60 50 60 10 TXK 60 66 54 65 47 / 90 70 60 60 10 ELD 66 72 55 65 44 / 70 70 60 60 20 TYR 61 65 51 65 47 / 90 60 60 30 10 GGG 62 67 53 66 47 / 90 70 60 50 10 LFK 69 75 57 69 49 / 70 70 60 50 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: ARZ050-051-059>061-070>072. LA...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: LAZ001>003. OK...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: OKZ077. TX...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138-149>151. && $$ 13
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 420 PM EDT MON MAY 12 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A DEEP MID LEVEL TROUGH FROM WRN MANITOBA INTO THE SRN ROCKIES RESULTING IN SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. AT THE SFC... LOW PRES WAS LOCATED OVER WRN WI WITH A COLD FRONT TO THE SE THROUGH CNTRL IA AND A WARM FRONT INTO NRN WI. RADARS INDICATED THERE WAS A GAP IN THE PCPN OVER NRN WI AND UPPER MI AS ONE MCS SLIDES TO THE E INTO WRN LOWER MI AND ANOTHER LINE OF CONVECTION STRETCHED TO THE SW FROM ERN IA. WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA...AREAS OF FOG HAD DEVELOPED ESPECIALLY IN AREAS WITH UPSLOPE ERLY FLOW. TONIGHT...AS SFC LOW PRES LIFTS FROM WRN WI ACROSS WRN LAKE SUPERIOR TONIGHT...THE WARM FRONT WILL ATTEMPT TO MOVE INTO UPPER MI. AT THIS POINT...IT APPEARS THE WARM FRONT MAY JUST SLIP INTO FAR SRN UPPER MI. SHRA/TSRA ARE EXPECTED TO DEVELOP BUT THE GREATEST COVERAGE IS EXPECTED FROM WI INTO FAR SRN UPPER MI...CLOSER TO THE HIGHER INSTABILITY AND MORE FAVORABLE LOW LEVEL INFLOW. WITH ELEVATED CAPE UP AROUND 1000J/KG AND DEEP LAYER SHEAR AROUND 30KT OR SO...STORMS WILL HAVE THE POTENTIAL TO BECOME ORGANIZED WITH ISOLD SVR POSSIBLE...MAINLY OVER FAR SCNTRL UPPER MI...CLOSER TO WARM FRONT. THE MAIN THREAT SHOULD BE HAIL...BUT WITH PWATS NEAR 1.5 INCH ...HEAVY RAINFALL WILL ALSO BE POSSIBLE. ADDITIONAL SHRA/TSRA MAY ALSO DEVELOP LATE TONIGHT ALONG THE COLD FRONT AS IT MOVES INTO THE W HALF BTWN 06Z-12Z. TUE...SHRA/TSRA WILL BE LIKELY IN THE MORNING OVER THE EAST HALF AS THE COLD FRONT MOVES THROUGH THE AREA. OTHERWISE...STRONG DRYING WILL MOVE INTO THE REST OF THE CWA. TEMPERATURES MAY CLIMB TO AROUND 60 BEFORE CAA STRENGTHENS IN THE AFTERNOON. GUSTY WEST WINDS WILL ALSO DEVELOP ESPECIALLY ACROSS THE HIGHER TERRAIN OF THE KEWEENAW. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 401 PM EDT MON MAY 12 2014 NAM SHOWS A CLOSED 500 MB LOW OVER EASTERN MANITOBA 00Z WED WITH A TROUGH OVER THE UPPER GREAT LAKES AND A RIDGE ON THE WEST COAST. THIS TROUGH DOES NOT MOVE MUCH THROUGH THU. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE THROUGH THE PERIOD WITH THE STRONGEST CONVERGENCE OVER THE ERN CWA. MOISTURE STAYS LIMITED UNTIL THU AND WILL REMAIN DRY THROUGH WED NIGHT BEFORE MOISTURE MOVES IN. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THIS FORECAST PERIOD AND DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A RIDGE OVER THE WESTERN U.S. PATTERN CHANGES LITTLE 12Z SAT WITH THE RIDGE MOVING INTO THE PLAINS ON SUN AND THE TROUGH MOVING INTO THE LOWER GREAT LAKES. THE RIDGE MOVES INTO THE MISSISSIPPI RIVER VALLEY ON MON. TEMPERATURES LOOK TO STAY BELOW NORMAL THIS FORECAST PERIOD WITH A SLOW MODIFICATION TREND AND LOOKS WET THIS FORECAST PERIOD UNTIL SUN AND SUN NIGHT WHEN THE UPPER RIDGE MOVES IN. OTHERWISE...PCPN CHANCES WILL STAY LOW THROUGH THE PERIOD. HAVING SOME SNOW IN DURING THE LATE NIGHT AND EARLY MORNING HOURS THU NIGHT THROUGH SAT MORNING STILL LOOKS GOOD AS WELL WITH COLD ENOUGH TEMPERATURES TO NOT COMPLETELY RULE THIS POSSIBILITY OUT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 142 PM EDT MON MAY 12 2014 AFTER THE WIDESPREAD MODERATE RAINFALL...ABUNDANT LOW LEVEL MOISTURE WILL REMAIN ACROSS THE REGION THIS AFTERNOON EVEN THOUGH THERE WILL LITTLE ADDITIONAL RAIN. AS A RESULT...LIFR CONDITIONS WILL LINGER INTO THIS EVENING. SHRA WILL REDEVELOP TONIGHT WITH LIFR/IFR CONDITIONS PREVAILING. THERE COULD BE SOME TSRA AS WELL...PARTICULARLY AROUND KSAW...BUT LIMITED CONFIDENCE IN TIMING/COVERAGE OF TSRA PRECLUDES A MENTION IN THIS FCST. CONDITIONS WILL IMPROVE TO MVFR TUE MORNING WITH LOW LEVEL DRYING IN THE WAKE OF A COLD FRONT. WEST WINDS WILL ALSO BECOME GUSTY...ESPECIALLY AT CMX. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 420 PM EDT MON MAY 12 2014 NE GALES ACROSS WRN LAKE SUPERIOR LATE THIS AFTERNOON INTO THIS EVENING WILL DIMINISH OVERNIGHT AS LOW PRES LIFTS TOWARD THE AREA AND THE PRES GRADIENT WEAKENS. ONCE THE LOW MOVES NORTH OF THE LAKE TUE MORNING...STRONG WEST WINDS WILL DEVELOP. THE GUSTY WINDS WILL SLOWLY DIMINISHING BELOW 25 KTS BY WEDNESDAY MORNING. WINDS FOR THE REST OF THE WEEK WILL MAINLY BE BLO 20 KTS. HOWEVER...A LOW PRESSURE SYSTEM COULD IMPACT THE REGION LATE THIS WEEK WITH WINDS OVER 25 KTS THURSDAY INTO FRIDAY. UNCERTAINTY IS HIGH WITH THAT SYSTEM THOUGH...SO CURRENT FORECAST WILL ONLY CALL FOR NORTHWEST TO 20 KTS AT THIS TIME. && .HYDROLOGY... ISSUED AT 401 PM EDT MON MAY 12 2014 RAINFALL AMOUNTS FOR THIS WHOLE RAIN EVENT THROUGH TUE AFTERNOON MAY EXCEED ONE TO ONE AND A HALF INCHES OVER PORTIONS OF WESTERN UPR MICHIGAN. RAIN CHANCES DIMINISH FROM WEST TO EAST ON TUESDAY AS A FRONTAL BOUNDARY EXITS THE REGION. RAINFALL WILL ONLY ADD TO THE ONGOING SNOWMELT AND ALREADY HIGH FLOWS ON AREA RIVERS AND STREAMS. THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE...THE STURGEON RIVER AT CHASSELL AND ALSTON AND THE MICHIGAMME RIVER DOWNSTREAM OF THE WAY DAM TO THE EAST OF CRYSTAL FALLS ARE UNDER FLOOD WARNINGS. GIVEN THE RAINFALL THAT WILL OCCUR THE NEXT 24-36 HOURS...RIVER LEVELS WILL KEEP RISING AND ADJUSTMENTS WILL LIKELY BE NEEDED BASED ON LATEST TRENDS. ALL THIS WATER DUE TO THE SNOWMELT AND THE RAINFALL WILL TAKE A WHILE TO WORK THROUGH THE RIVERS...SO IT IS QUITE LIKELY THAT HIGHER RIVER FLOWS AND THE ASSOCIATED ADVISORIES AND WARNINGS ON AREA RIVERS WILL CONTINUE THROUGH LATE THIS WEEK...IF NOT INTO THIS WEEKEND. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...07 AVIATION...JLB MARINE...JLB HYDROLOGY...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 515 AM EDT MON MAY 12 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A BUILDING RIDGE ALONG THE W COAST OF NAMERICA WITH AMPLIFIED DOWNSTREAM TROF OVER THE ROCKIES. MAIN PIECE OF ENERGY IS IN THE BASE OF THE TROF OVER COLORADO. WAA/ISENTROPIC ASCENT DOWNSTREAM INTO THE UPPER LAKES IS SUPPORTING A LARGE AREA OF SHRA/TSRA LIFTING NE ACROSS MN/WI EARLY THIS MORNING. SHORTWAVE MOVING NE INTO WRN WI IS FURTHER AIDING THE PCPN. INSTABILITY HAS BEEN SLOW TO ADVANCE N PER SPC MESOANALYIS...SO WHILE SHRA ARE ADVANCING STEADILY N AND E...TSRA ARE LAGGING FARTHER AND FARTHER S WITHIN THE OVERALL SHRA AREA. HIGH RES MODEL GUIDANCE...PARTICULARLY THE HIGH RES RAPID REFRESH... HAS A DECENT HANDLE ON APPROACHING SHRA. UTILIZED RADAR TRENDS AND HIGH RES GUIDANCE TO SWING A PERIOD OF CATEGORICAL POPS ACROSS THE FCST AREA THIS MORNING. FORTUNATELY...PCPN AMOUNTS DON`T LOOK TO BE EXCESSIVE AS MAIN AREA OF TSRA WILL PASS BY TO THE S. STILL... EXPECT ROUGHLY 0.5 TO 0.75 INCHES WHICH WILL GIVE AREA RIVERS/STREAMS A BOOST IN FLOW. AS SUPPORTING SHORTWAVE MOVES NE OF THE AREA...MUCH OF THE AFTN MAY TURN DRY IN ITS WAKE. POPS WERE LOWERED INTO THE CHC/SCT CATEGORY...BUT BELIEVE MANY AREAS WILL PROBABLY SEE A GOOD PERIOD OF DRY WEATHER THIS AFTN. WITH PCPN AT A MINIMUM DURING THE AFTN...TEMPS WILL HAVE A CHANCE TO RESPOND...AT LEAST IN AREAS WHERE GENERAL EASTERLY FLOW IS NOT OFF THE GREAT LAKES. BUMPED TEMPS UP INTO THE UPPER 50S/LWR 60S ACROSS MUCH OF THE INTERIOR. HIGH RES RAPID REFRESH SHOWS TEMPS RISING TO AROUND 70F OVER THE INTERIOR W THIS AFTN...CERTAINLY POSSIBLE IF CLOUDS THIN OUT SUFFICIENTLY. AS SFC LOW PRES LIFTS FROM WRN WI ACROSS WRN LAKE SUPERIOR TONIGHT...WARM FRONT WILL ATTEMPT TO MOVE INTO UPPER MI. AT THIS POINT...IT APPEARS THE WARM FRONT MAY JUST SLIP INTO FAR SRN UPPER MI. ADDITIONAL SHRA/TSRA WILL LIKELY DEVELOP AS SFC LOW/WARM FRONT LIFT N...THOUGH PCPN COVERAGE PROBABLY WON`T BE AS WIDESPREAD AS WHAT WILL OCCUR THIS MORNING. WITH ELEVATED CAPE UP AROUND 1000J/KG AND DEEP LAYER SHEAR AROUND 30KT OR SO...STORMS WILL HAVE THE POTENTIAL TO BECOME ORGANIZED WITH ISOLD SVR POSSIBLE...MAINLY OVER FAR SCNTRL UPPER MI...CLOSER TO WARM FRONT. MAIN THREAT SHOULD BE HAIL...BUT WITH PRECIPITABLE WATER 200-250PCT OF NORMAL...HVY RAINFALL WILL BE A GOOD BET WITH ANY TSRA. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 401 PM EDT MON MAY 12 2014 NAM SHOWS A CLOSED 500 MB LOW OVER EASTERN MANITOBA 00Z WED WITH A TROUGH OVER THE UPPER GREAT LAKES AND A RIDGE ON THE WEST COAST. THIS TROUGH DOES NOT MOVE MUCH THROUGH THU. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE THROUGH THE PERIOD WITH THE STRONGEST CONVERGENCE OVER THE ERN CWA. MOISTURE STAYS LIMITED UNTIL THU AND WILL REMAIN DRY THROUGH WED NIGHT BEFORE MOISTURE MOVES IN. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THIS FORECAST PERIOD AND DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A RIDGE OVER THE WESTERN U.S. PATTERN CHANGES LITTLE 12Z SAT WITH THE RIDGE MOVING INTO THE PLAINS ON SUN AND THE TROUGH MOVING INTO THE LOWER GREAT LAKES. THE RIDGE MOVES INTO THE MISSISSIPPI RIVER VALLEY ON MON. TEMPERATURES LOOK TO STAY BELOW NORMAL THIS FORECAST PERIOD WITH A SLOW MODIFICATION TREND AND LOOKS WET THIS FORECAST PERIOD UNTIL SUN AND SUN NIGHT WHEN THE UPPER RIDGE MOVES IN. OTHERWISE...PCPN CHANCES WILL STAY LOW THROUGH THE PERIOD. HAVING SOME SNOW IN DURING THE LATE NIGHT AND EARLY MORNING HOURS THU NIGHT THROUGH SAT MORNING STILL LOOKS GOOD AS WELL WITH COLD ENOUGH TEMPERATURES TO NOT COMPLETELY RULE THIS POSSIBILITY OUT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 142 PM EDT MON MAY 12 2014 AFTER THE WIDESPREAD MODERATE RAINFALL...ABUNDANT LOW LEVEL MOISTURE WILL REMAIN ACROSS THE REGION THIS AFTERNOON EVEN THOUGH THERE WILL LITTLE ADDITIONAL RAIN. AS A RESULT...LIFR CONDITIONS WILL LINGER INTO THIS EVENING. SHRA WILL REDEVELOP TONIGHT WITH LIFR/IFR CONDITIONS PREVAILING. THERE COULD BE SOME TSRA AS WELL...PARTICULARLY AROUND KSAW...BUT LIMITED CONFIDENCE IN TIMING/COVERAGE OF TSRA PRECLUDES A MENTION IN THIS FCST. CONDITIONS WILL IMPROVE TO MVFR TUE MORNING WITH LOW LEVEL DRYING IN THE WAKE OF A COLD FRONT. WEST WINDS WILL ALSO BECOME GUSTY...ESPECIALLY AT CMX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 504 AM EDT MON MAY 12 2014 EXPECT PERIOD OF STRONGER WINDS OVER LAKE SUPERIOR. APPROACHING LOW PRESSURE SYSTEM RESULTS IN NORTHEAST WINDS INCREASING TO GALES BY AFTN OVER WEST HALF OF LK SUPERIOR. WINDS TO 30 KTS OVER REST OF LK SUPERIOR. STRONG WINDS DIMINISH BRIEFLY LATER THIS EVENING AND OVERNIGHT TONIGHT AS THE LOW SLIDES ACROSS WESTERN LK SUPERIOR. ONCE THE LOW MOVES NORTH OF THE LAKE ON TUESDAY MORNING...STRONG WEST WINDS KICK UP. EXPECT THESE STRONG WESTERLIES...PROBABLY REACHING GALES ON TUESDAY OVER NCNTRL LK SUPERIOR...TO SLOWLY FADE BLO 25 KTS BY WEDNESDAY MORNING. WINDS REST OF THE WEEK WILL MAINLY BE BLO 20 KTS. HOWEVER...A LOW PRESSURE SYSTEM COULD IMPACT THE REGION LATE THIS WEEK WITH WINDS OVER 25 KTS THURSDAY INTO FRIDAY. UNCERTAINTY IS HIGH WITH THAT SYSTEM THOUGH...SO CURRENT FORECAST WILL ONLY CALL FOR NORTHWEST TO 20 KTS AT THIS TIME. && .HYDROLOGY... ISSUED AT 401 PM EDT MON MAY 12 2014 RAINFALL AMOUNTS FOR THIS WHOLE RAIN EVENT THROUGH TUE AFTERNOON MAY EXCEED ONE TO ONE AND A HALF INCHES OVER PORTIONS OF WESTERN UPR MICHIGAN. RAIN CHANCES DIMINISH FROM WEST TO EAST ON TUESDAY AS A FRONTAL BOUNDARY EXITS THE REGION. RAINFALL WILL ONLY ADD TO THE ONGOING SNOWMELT AND ALREADY HIGH FLOWS ON AREA RIVERS AND STREAMS. THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE...THE STURGEON RIVER AT CHASSELL AND ALSTON AND THE MICHIGAMME RIVER DOWNSTREAM OF THE WAY DAM TO THE EAST OF CRYSTAL FALLS ARE UNDER FLOOD WARNINGS. GIVEN THE RAINFALL THAT WILL OCCUR THE NEXT 24-36 HOURS...RIVER LEVELS WILL KEEP RISING AND ADJUSTMENTS WILL LIKELY BE NEEDED BASED ON LATEST TRENDS. ALL THIS WATER DUE TO THE SNOWMELT AND THE RAINFALL WILL TAKE A WHILE TO WORK THROUGH THE RIVERS...SO IT IS QUITE LIKELY THAT HIGHER RIVER FLOWS AND THE ASSOCIATED ADVISORIES AND WARNINGS ON AREA RIVERS WILL CONTINUE THROUGH LATE THIS WEEK...IF NOT INTO THIS WEEKEND. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...07 AVIATION...JLB MARINE...JLA HYDROLOGY...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
144 PM EDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 515 AM EDT MON MAY 12 2014 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A BUILDING RIDGE ALONG THE W COAST OF NAMERICA WITH AMPLIFIED DOWNSTREAM TROF OVER THE ROCKIES. MAIN PIECE OF ENERGY IS IN THE BASE OF THE TROF OVER COLORADO. WAA/ISENTROPIC ASCENT DOWNSTREAM INTO THE UPPER LAKES IS SUPPORTING A LARGE AREA OF SHRA/TSRA LIFTING NE ACROSS MN/WI EARLY THIS MORNING. SHORTWAVE MOVING NE INTO WRN WI IS FURTHER AIDING THE PCPN. INSTABILITY HAS BEEN SLOW TO ADVANCE N PER SPC MESOANALYIS...SO WHILE SHRA ARE ADVANCING STEADILY N AND E...TSRA ARE LAGGING FARTHER AND FARTHER S WITHIN THE OVERALL SHRA AREA. HIGH RES MODEL GUIDANCE...PARTICULARLY THE HIGH RES RAPID REFRESH... HAS A DECENT HANDLE ON APPROACHING SHRA. UTILIZED RADAR TRENDS AND HIGH RES GUIDANCE TO SWING A PERIOD OF CATEGORICAL POPS ACROSS THE FCST AREA THIS MORNING. FORTUNATELY...PCPN AMOUNTS DON`T LOOK TO BE EXCESSIVE AS MAIN AREA OF TSRA WILL PASS BY TO THE S. STILL... EXPECT ROUGHLY 0.5 TO 0.75 INCHES WHICH WILL GIVE AREA RIVERS/STREAMS A BOOST IN FLOW. AS SUPPORTING SHORTWAVE MOVES NE OF THE AREA...MUCH OF THE AFTN MAY TURN DRY IN ITS WAKE. POPS WERE LOWERED INTO THE CHC/SCT CATEGORY...BUT BELIEVE MANY AREAS WILL PROBABLY SEE A GOOD PERIOD OF DRY WEATHER THIS AFTN. WITH PCPN AT A MINIMUM DURING THE AFTN...TEMPS WILL HAVE A CHANCE TO RESPOND...AT LEAST IN AREAS WHERE GENERAL EASTERLY FLOW IS NOT OFF THE GREAT LAKES. BUMPED TEMPS UP INTO THE UPPER 50S/LWR 60S ACROSS MUCH OF THE INTERIOR. HIGH RES RAPID REFRESH SHOWS TEMPS RISING TO AROUND 70F OVER THE INTERIOR W THIS AFTN...CERTAINLY POSSIBLE IF CLOUDS THIN OUT SUFFICIENTLY. AS SFC LOW PRES LIFTS FROM WRN WI ACROSS WRN LAKE SUPERIOR TONIGHT...WARM FRONT WILL ATTEMPT TO MOVE INTO UPPER MI. AT THIS POINT...IT APPEARS THE WARM FRONT MAY JUST SLIP INTO FAR SRN UPPER MI. ADDITIONAL SHRA/TSRA WILL LIKELY DEVELOP AS SFC LOW/WARM FRONT LIFT N...THOUGH PCPN COVERAGE PROBABLY WON`T BE AS WIDESPREAD AS WHAT WILL OCCUR THIS MORNING. WITH ELEVATED CAPE UP AROUND 1000J/KG AND DEEP LAYER SHEAR AROUND 30KT OR SO...STORMS WILL HAVE THE POTENTIAL TO BECOME ORGANIZED WITH ISOLD SVR POSSIBLE...MAINLY OVER FAR SCNTRL UPPER MI...CLOSER TO WARM FRONT. MAIN THREAT SHOULD BE HAIL...BUT WITH PRECIPITABLE WATER 200-250PCT OF NORMAL...HVY RAINFALL WILL BE A GOOD BET WITH ANY TSRA. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 504 AM EDT MON MAY 12 2014 DEEP TROUGH FOR MAY AND REALLY ANYTIME OF THE YEAR STRETCHES FROM CENTRAL CANADA TO THE SOUTHERN PLAINS ON TUESDAY. SFC LOW CURRENTLY OVER THE CENTRAL PLAINS SHOULD BE JUST NORTHWEST OF LK SUPERIOR DAYBREAK ON TUESDAY. OCCLUDED FRONT WILL BE SLICING ACROSS CWA THROUGH MID MORNING...EXITING EASTERN CWA BY EARLY AFTN. SHOULD BE AT LEAST SCT SHRA/TSRA EXPECTED ALONG AND AHEAD OF FRONT AS HIGHER 1000-850MB THETA-E POOLS ALONG THE BOUNDARY. SHARP DRYING ENDS ANY RAIN QUICKLY OVER WEST HALF IN THE MORNING...BUT MAY SEE ISOLD SHRA/TSRA OVER FAR SOUTHEAST CWA AS WEAK LOW-LEVEL CONVERGENCE LINGERS AND AS ANOTHER WEAKER SHORTWAVE/Q-VECTOR CONVERGENCE AT H85-H5 LIFTS OVER FAR EAST CWA. ANY STORMS AHAEAD OF FRONT IN THE MORNING SHOULD BE WEAK AS 1-6KM MUCAPE AND MLCAPE BOTH DIMINISH STEADILY COMPARED TO THE OVERNIGHT HOURS. TEMPS WILL RISE INTO THE 60S OVER THE CNTRL WHERE WEST WINDS DOWNSLOPE...IMT-ESC-MNM...BUT WILL STAY IN THE 50S OVER THE WESTERN/NORTHWEST CWA WITH GRADIENT WINDS OFF LK SUPERIOR. THOSE WINDS COULD BE QUITE GUSTY...ESPECIALLY OVER THE MORE EXPOSED KEWEENAW...WHERE NAM/GFS SOUNDINGS INDICATE MIXED LAYER BUILDING TO H85-H8 WITH WINDS OVER 35 KTS IN THE MIXED LAYER. QUIET WEATHER TUESDAY NIGHT AND WEDNESDAY AS DEEP SFC LOW SLOWLY LIFTS TO JAMES BAY/HUDSON BAY. GRADIENT WEST FLOW STAYS OVER UPR MICHIGAN...BUT WILL LIGHTEN ENOUGH ON WEDNESDAY TO RESULT IN LAKE BREEZES. SLIM CHANCE THAT RESULTING LOW-LEVEL CONVERGENCE ADDED TO WEAK H7-H5 FORCING FM SHORTWAVE DROPPING ACROSS ON PERIFERY OF DEEP TROUGH ALOFT COULD TRIGGER A FEW SHOWERS/SPRINKLES INTERIOR CENTRAL. DEEP MIXING TO H8 WILL LIMIT POTENTIAL THOUGH AS LOW-LEVEL RH VALUES DROP OFF BLO 40 PCT. MAX TEMPS SHOULD PUSH INTO THE 50S INLAND AND FALL BACK INTO THE 40S NEAR LK SUPERIOR ONCE LAKE BREEZE DEVELOPS. THE FORECAST FOR THURSDAY INTO FRIDAY REMAINS UNCERTAIN. AT THE LEAST...TEMPS WILL BE BLO NORMAL FOR MOST CWA...PERHAPS BY MORE THAN 10-15F OVER THE NORTHERN CWA. ECMWF STILL SUPPORTS POTENTIAL FOR ACCUMULATING SNOW...NOW MAINLY DELAYED UNTIL THURSDAY NIGHT THROUGH FRIDAY AND POSSIBLY INTO FRIDAY NIGHT. LATEST UKMET ALSO IN LINE WITH THE ECMWF IDEA. MEANWHILE...GFS AND GEM-NH STAY WITH PROGRESSIVE IDEA INDICATING STRONG SHORTWAVE ROUNDING BASE OF DEEP TROUGH STAYS SEPARATE ENOUGH FROM TROUGH FROM HUDSON BAY TO THE NORTHERN PLAINS TO LIMIT PHASING. IF GFS THEME IDEA IS RIGHT...WOULD SEE SETUP WITH MORE DIURNALLY DRIVEN MAINLY RAIN SHOWERS DUE TO INSTABILITY ALOFT BENEATH THE TROUGH AXIS. IF THE ECMWF AND UKMET ARE ON THE RIGHT TRACK...THEY INDICATE ENOUGH PHASING BTWN THE LARGE SCALE TROUGHS TO DRAG A SFC LOW PRESSURE SYSTEM NORTHWARD OVER THE CNTRL GREAT LAKES INTO TOWARD THE UPPER GREAT LAKES THURSDAY INTO FRIDAY. WITH THAT SCNEARIO...WIDESPREAD RAIN AND SNOW THURSDAY EVENING WOULD CHANGE TO SNOW THURSDAY NIGHT INTO MUCH OF FRIDAY AND NORTHERLY FLOW WOULD ONLY BOOST THE SNOW OVER HIGHER TERRAIN AREAS NEAR LK SUPERIOR. SNOW COULD BE PRETTY WIDESRPEAD AS PYTPE WITH H85 TEMPS DROPPING BLO -5C AND SINCE 1000-850MB THICKNESSES FALL BLO 1300M. PHASING SYSTEMS ARE ALWAYS TOUGH TO FORECAST. ADD TO THAT FACT THAT WE ARE PUSHING INTO MIDDLE OF MAY AND IT MAKES IT REALLY TOUGH TO SAY IF UKMET AND ECMWF SOLUTION WILL WORK OUT AS FORECAST. SINCE ECMWF ENSEMBLE MEAN WOULD ALSO SUPPORT SIMILAR IDEA AND SOME CANADIAN ENSEMBLES HAVE SHOWN THIS RECENTLY IT DOES SUGGEST THE IDEA AT LEAST HAS SOME MERIT COMPARED TO JUST ONE ROUGE OPERATIONAL MODEL RUN SHOWING A BIG STORM IN THE FAR REACHES OF THE EXTENDED. ONCE THE SYSTEM OR JUST THE OPEN TROUGH MOVES BY...WEEKEND LOOKS DRIER WITH GRADUAL WARMING TREND. DID NOT STRAY FROM CONSENSUS LOW CHANCE POPS FOR NEXT WEEKEND ATTM. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 142 PM EDT MON MAY 12 2014 AFTER THE WIDESPREAD MODERATE RAINFALL...ABUNDANT LOW LEVEL MOISTURE WILL REMAIN ACROSS THE REGION THIS AFTERNOON EVEN THOUGH THERE WILL LITTLE ADDITIONAL RAIN. AS A RESULT...LIFR CONDITIONS WILL LINGER INTO THIS EVENING. SHRA WILL REDEVELOP TONIGHT WITH LIFR/IFR CONDITIONS PREVAILING. THERE COULD BE SOME TSRA AS WELL...PARTICULARLY AROUND KSAW...BUT LIMITED CONFIDENCE IN TIMING/COVERAGE OF TSRA PRECLUDES A MENTION IN THIS FCST. CONDITIONS WILL IMPROVE TO MVFR TUE MORNING WITH LOW LEVEL DRYING IN THE WAKE OF A COLD FRONT. WEST WINDS WILL ALSO BECOME GUSTY...ESPECIALLY AT CMX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 504 AM EDT MON MAY 12 2014 EXPECT PERIOD OF STRONGER WINDS OVER LAKE SUPERIOR. APPROACHING LOW PRESSURE SYSTEM RESULTS IN NORTHEAST WINDS INCREASING TO GALES BY AFTN OVER WEST HALF OF LK SUPERIOR. WINDS TO 30 KTS OVER REST OF LK SUPERIOR. STRONG WINDS DIMINISH BRIEFLY LATER THIS EVENING AND OVERNIGHT TONIGHT AS THE LOW SLIDES ACROSS WESTERN LK SUPERIOR. ONCE THE LOW MOVES NORTH OF THE LAKE ON TUESDAY MORNING...STRONG WEST WINDS KICK UP. EXPECT THESE STRONG WESTERLIES...PROBABLY REACHING GALES ON TUESDAY OVER NCNTRL LK SUPERIOR...TO SLOWLY FADE BLO 25 KTS BY WEDNESDAY MORNING. WINDS REST OF THE WEEK WILL MAINLY BE BLO 20 KTS. HOWEVER...A LOW PRESSURE SYSTEM COULD IMPACT THE REGION LATE THIS WEEK WITH WINDS OVER 25 KTS THURSDAY INTO FRIDAY. UNCERTAINTY IS HIGH WITH THAT SYSTEM THOUGH...SO CURRENT FORECAST WILL ONLY CALL FOR NORTHWEST TO 20 KTS AT THIS TIME. && .HYDROLOGY... ISSUED AT 504 AM EDT MON MAY 12 2014 WIDESRPEAD MODERATE TO HEAVY RAIN WILL AFFECT ALL OF UPR MICHIGAN THROUGH EARLY THIS AFTN BEFORE DIMINISHING...THEN THERE MAY BE ANOTHER PERIOD OF MODERATE RAINFALL TONIGHT. RAINFALL AMOUNTS MAY EXCEED ONE INCH TODAY OVER PORTIONS OF WESTERN UPR MICHIGAN. RAIN CHANCES DIMINISH FROM WEST TO EAST ON TUESDAY AS A FRONTAL BOUNDARY EXITS THE REGION. RAINFALL WILL ONLY ADD TO THE ONGOING SNOWMELT AND ALREADY HIGH FLOWS ON AREA RIVERS AND STREAMS. THE PRIMARY CHANGE TO ONGOING HEADLINES WAS LAST EVENING...WHEN BASED ON EXPECTED RAINFALL...WHICH LOOKS LIKE IT IS WORKING OUT...ADVISORIES WERE UPGRADED TO WARNINGS FOR THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. THE WARNING FOR THE STURGEON RIVER NEAR CHASSELL AND THE ADVISORY FOR THE STURGEON RIVER NEAR ALSTON CONTINUE...AS DOES THE ADVISORY FOR THE MICHIGAMME RIVER DOWNSTREAM OF WAY DAM...TO THE EAST OF CRYSTAL FALLS IN IRON COUNTY. GIVEN THE RAINFALL THAT WILL AFFECT THE AREA THE NEXT 24-36 HOURS...RIVER LEVELS WILL KEEP RISING AND ADJUSTMENTS WILL LIKELY BE NEEDED BASED ON LATEST TRENDS. ALL THIS WATER DUE TO THE SNOWMELT AND THE RAINFALL WILL TAKE A WHILE TO WORK THROUGH THE RIVERS...SO IT IS QUITE LIKELY THAT HIGHER RIVER FLOWS AND THE ASSOCIATED ADVISORIES AND WARNINGS ON AREA RIVERS WILL CONTINUE THROUGH LATE THIS WEEK...IF NOT INTO NEXT WEEKEND. THOSE LIVING NEAR RIVERS...CREEKS...AND STREAMS SHOULD CONTINUE TO MONITOR THE LATEST RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR LSZ162. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...JLB MARINE...JLA HYDROLOGY...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1220 PM CDT MON MAY 12 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 334 AM CDT MON MAY 12 2014 SHOWERS ARE PUSHING EAST OF OUR WEST CENTRAL WI COUNTIES EARLY THIS MORNING WITH JUST A FEW SCATTERED SHOWERS ACROSS THE MN COUNTIES. RAINFALL AMOUNTS OVERNIGHT FROM 1 TO 1.50 INCHES HAVE BEEN COMMON ACROSS SOUTHERN MN AND ADJOINING AREAS OF WEST CENTRAL WI. RAINFALL AMOUNTS DROP OFF TO AROUND A HALF INCH FROM WEST CENTRAL MN TO NW WI. THE DAY AHEAD WILL FEATURE A LOW PRESSURE SYSTEM MOVING SLOWLY NORTHEAST FROM IA TO THE SOUTHERN TWIN CITIES METRO BY EARLY THIS AFTERNOON. THE LOW SHOULD REACH FAR NORTHERN WI BY LATE THIS EVENING. THERE IS PLENTY OF POTENTIAL FOR SEVERE STORMS TO DEVELOP THIS AFTERNOON/EVENING IN THE VICINITY OF THE SURFACE LOW AND WARM FRONT EXTENDING TO THE EAST. LIMITING FACTORS WILL BE THE EXTENSIVE CLOUDINESS THAT WILL HOLD DOWN ON THE DESTABILIZATION. RAP DATA SHOWS A WARM POCKET MOVING NORTHEAST FROM IA THIS MORNING BETWEEN 650-700MB. THIS IS SQUARELY OVER WEST CENTRAL WI EARLY THIS AFTERNOON. LOW LEVEL LAPSE RATES SUFFER AS WELL AS SURFACE BASED CAPE. HOWEVER...BY LATE IN THE AFTERNOON...SOUNDING DATA FOR KEAU SHOWS THE POTENTIAL TO WARM ENOUGH TO GET PAST THE MID LEVEL WARM POCKET. SURFACE BASED CAPE REACHES A LITTLE MORE THAN 2000 J/KG. SHEAR IS ADEQUATE WITH 0-1KM REACHING 25 KNOTS WITH 0-6KM BETTER THAN 45 KNOTS. 500MB WINDS ARE VERY IMPRESSIVE WITH A CORE OF 60-70 KNOT WINDS PROGGED ACROSS THE TWIN CITIES AND WEST CENTRAL WI THIS AFTERNOON. OUR MPXWRF...THE HOPWRF AND THE SPCWRF START BREWING TROUBLE ALONG OUR MN/WI BORDER AREA BY 21Z WITH THE HINT OF A FEW SUPERCELLS ACROSS WEST CENTRAL WI INTO THE EARLY EVENING. GIVEN THE LOW LCLS...SHEAR AND WARM FRONT...A TORNADO OR TWO CAN NOT BE RULED OUT. IN FACT...THERE HAVE BEEN TORNADOES THE PAST TWO DAYS NEAR THE SURFACE LOW AND WARM FRONT. NORTHWEST WINDS WILL STRENGTHEN ACROSS THE FA TONIGHT IN THE WAKE OF THE LOW PRESSURE SYSTEM. THIS WILL USHER IN MUCH COOLER AIR THAT WILL BE WITH US FOR THE BALANCE OF THE WEEK AS A LARGE TROUGH ALOFT DOMINATES ACROSS THE MISSISSIPPI VALLEY REGION. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 334 AM CDT MON MAY 12 2014 THE THEME FOR THE LONG TERM PERIOD IS DRY WEATHER FOR THE UPPER MIDWEST. ALTHOUGH...IT WILL ALSO BE A COOL PERIOD MAINLY TUESDAY THROUGH FRIDAY AS TEMPERATURES WILL RUN 10 TO 15 DEGREES BELOW NORMAL. PICKING UP TUESDAY MORNING...THE UPPER LEVEL TROUGH AXIS WILL BE IN THE VICINITY OF THE WESTERN MN/EASTERN DAKOTAS BORDER. THE SURFACE LOW WILL HAVE LIFTED UP INTO ONTARIO NORTH OF LAKE SUPERIOR. THE NAM REMAINS STUBBORN IN HAVING THE MOVEMENT OF THE LOW A TAD SLOWER/GIVEN ITS DEEPER SOLUTION WITH THE TROUGH MONDAY NIGHT/...BUT IT HAS STARTED TO MOVE TOWARD THE GFS/EC SOLUTIONS. PREFERRED A EC/GFS BLEND THAT HAS THE LOW QUICKLY MOVING NORTH. THE UPPER TROUGH AND MOISTURE ON THE BACK SIDE OF THE LOW WARRANTED THE MENTION OF POPS ACROSS THE NORTHERN PART OF THE FA...BUT ANY PRECIPITATION WILL BE VERY LIGHT. WITH THE UPPER TROUGH OVERHEAD...TEMPERATURES WILL BE HELD IN THE 50S DURING THE DAY...AND WITH THE DEPARTING LOW NORTHWEST WINDS WILL BE BLUSTERY AND MAKE FOR A COOL DAY. WINDS SHOULD SLACKEN AND SKY COVER BEGIN TO BREAK UP TUESDAY EVENING. 850H TEMPS WILL FALL BELOW ZERO OVERNIGHT AND GIVEN WEAKENING WINDS AND AND DIMINISHING SKY COVER OVERNIGHT...TEMPERATURES BY EARLY WEDNESDAY MORNING WILL BE IN THE 30S ACROSS THE FA. LITTLE CHANGE IS EXPECTED WEDNESDAY AS THE AMPLIFIED UPPER TROUGH AND CORE OF THE COOL AIR REMAINS OVERHEAD. MEANWHILE...BOTH THE EAST COAST AND WEST COAST WILL HAVE HIGHLY AMPLIFIED RIDGING AND WARM TEMPERATURES. SLIGHT CHANCE POPS DO SHOW UP AGAIN WEDNESDAY AFTERNOON ACROSS THE WEST AS ADDITIONAL MOISTURE ALOFT ROTATES SOUTH ON THE BACK SIDE OF THE UPPER TROUGH. WOULD NOT BE SURPRISED IF LOW LEVEL DRY AIR PREVENTS ANYTHING FROM REACHING THE GROUND. WEDNESDAY NIGHT WILL BE COLDER AS 850H TEMPS DROP TO -2C TO -6C GENERALLY ACROSS THE FA. WIDESPREAD 30S ARE EXPECTED WITH SOME SPOTS HITTING THE FREEZING MARK. THE AMPLIFIED TROUGH WILL PUSH SLIGHTLY EAST AND BECOME A CLOSED UPPER LOW OVER WISCONSIN THURSDAY NIGHT INTO FRIDAY SO CYCLONICALLY CURVED FLOW MAY AGAIN PRODUCE VERY LIGHT PRECIP THURSDAY AFTERNOON. THE POPS ASSOCIATED WITH THIS TROUGH DURING THE MIDWEEK MAY BE OVERDONE BY THE LARGE SCALE SYNOPTIC MODELS...HOWEVER...SO WHILE THERE ARE SOME POPS IN THE FORECAST FOR THE MIDWEEK TIME FRAME...TOTAL AMOUNTS WILL BE UNDER A TENTH OF AN INCH...AND WILL LIKELY BE ZERO FOR PARTS OF THE AREA. WE`LL SEE THE CORE OF THE COOL AIR ALOFT PUSH EAST AT THE START OF THE WEEKEND AS THE WESTERN CONUS RIDGE STARTS PUSHING INTO THE CENTER OF THE COUNTRY BY SUNDAY. BESIDES A COOL START...THE WEEKEND LOOKS DRY...PARTLY CLOUDY...AND WARMER THAN THE COLD MIDWEEK AHEAD. BEYOND THE WEEKEND...THE RIDGE AXIS WILL PUSH OVER OUR AREA EARLY NEXT WEEK AND TEMPERATURES WILL CONTINUE TO WARM. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1203 PM CDT MON MAY 12 2014 WEAK SFC LOW THAT WAS ACROSS EC MN THIS MORNING HAS SHIFTED FURTHER TO THE NE AND W/NW WINDS HAVE NEARLY MOVED THRU THE METRO AREA. ONLY AREAS WITH A SOUTHERLY WIND FLOW WAS ACROSS WC WI/SE MN WHERE THE BEST CHC OF ANY TSRA ACTIVITY IN THE NEXT 6 TO 12 HRS. IN ADDITION TO THE WINDS SHIFTING TO THE W/NW...CIGS DROP TO IFR/LIFR AND VSBYS DROP WITH DRIZZLE/-RA. MORE PERSISTENT SHRA WERE ACROSS SD/ND EARLY THIS AFTN. WILL CONTINUE CHC POPS...BUT IT WILL LIKELY BE MORE SCATTERED IN NATURE WITH A BETTER CHC OF WIDESPREAD ACTIVITY ACROSS WC MN DURING THE LATE AFTN AS THE MAIN UPPER LOW MOVES ACROSS THE UPPER MIDWEST. CIGS/VSBYS WILL REMAIN IFR/LIFR FOR THE BULK OF THE AFTN/EVENING ACROSS MN...WITH WC WI HAVING THE BEST CHC OF MVFR CIGS AND TSRA. CONFIDENCE IN TSRA REMAINS LOW FOR ALL MPX TAF SITES WITH THE EXCEPTION OF KEAU WHERE VCTS LOOKS REASONABLE FOR THIS AFTN/EVENING. WILL UPDATE KEAU AS PER LATEST RADAR AND ADJUST AS NEEDED. WINDS WILL REMAIN FROM THE NW/WNW THRU THE PERIOD ACROSS MN...WITH WINDS SHIFTING TO THE W/NW AT KRNH BY EARLY/MID AFTN...AND AT KEAU AFT 23Z. KMSP... WINDS HAVE SHIFTED TO THE NW IN THE LAST HR...WHICH BASICALLY CAUSES ANY CHC/S OF TSRA ALMOST NIL THIS AFTN WITH ONLY A SMALL CHC BASED ON MID LEVEL LAPSE RATES IN FAR EC MN. WILL LEAVE OUT VCTS ATTM...BUT WILL NEED TO SEE HOW CONVECTION DEVELOPS IN NC IA THIS AFTN. OTHERWISE...IFR CIGS WILL CONTINUE WITH VSBYS SLOWLY IMPROVING LATER THIS AFTN/EVENING AS WINDS INCREASE FROM THE WNW/NW AND BECOME GUSTY. SOME INSTABILITY SHRA ARE POSSIBLE TUESDAY AFTN...BUT NOT CONFIDENT ENOUGH TO WARRANT ANYTHING MORE THAN VCSH AFT 18Z. CIGS SHOULD BEGIN TO LIFT TUESDAY MORNING...WITH VFR CIGS DURING THE AFTN. /OUTLOOK FOR KMSP/ TUE AFTN...VFR. MVFR POSSIBLE IN -SHRA. WINDS W-NW 15-20 KTS. WED...VFR. WINDS W 5-15 KTS. THU...VFR. WINDS N/NE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...RAH LONG TERM...SPD AVIATION...JLT
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1239 PM CDT Mon May 12 2014 .SHORT TERM: (Today and Tonight) Issued at 330 AM CDT Mon May 12 2014 Main forecast issues for today are the probability of thunderstorms and any severe potential, as well as just how warm it may get. Current thinking is there should be a gradual upswing in convection as the day progresses, primarily during the later half of the afternoon. It appears that northeast Missouri will be the area we will have to watch most closely through mid morning. Two things to key an eye on - an outflow boundary pushing southeastward across eastern Iowa as a focus for additional thunderstorms, and also a cluster of thunderstorms across eastern Kansas just southwest of Kansas City and if they will hold together as they move northeastward. Otherwise I think that there will be a general decrease in the convective cloud debris during the morning, which given the mild early morning temperatures should allow for a quick warm-up by early afternoon. The convection allowing models and more specifically the HRRR is suggesting that by mid morning, isolated showers or thunderstorms could develop just about anywhere within the CWA, but most favored across southeast Missouri and southern Illinois. The main action still looks like the later half of the afternoon. The warm sector air mass ahead of the cold front will become quite unstable by mid-late afternoon with SBCAPE in excess of 2000 J/KG and little CIN. Expecting numerous thunderstorms to develop across western Missouri into central and northeast Missouri. Deep layer shear of 20-30 kts and the anticipated CAPE would support a few severe storms capable of large hail and damaging winds from the afternoon into about mid-evening. The front moves through all but the far eastern sections of the CWA tonight accompanied by widespread showers and thunderstorms and ushering much cooler air into the region in its wake. It also appears that there will be an increasing amount of post-frontal showers overnight immediately in the cool air in response to large scale forcing. Glass .LONG TERM: (Tuesday through Sunday) Issued at 330 AM CDT Mon May 12 2014 This marks the beginning of a cooler than normal period with a slow-moving and deep upper trof dominating the region through the week. The front will quickly exit the remainder of the CWA early Tuesday morning with post-frontal showers impacting eastern Missouri and southwest Illinois in the morning and exiting by early-mid afternoon. Highs on Tuesday will be around 20 degrees cooler than today. A strong short-wave and possibly upper low will then migrate through the base of the deep trof from the southern Plains and into the mid MS valley Tuesday night-Wednesday night. More reminiscent of Fall or early Spring, large scale ascent with this system should produce a large area of showers or rain spreading into the area late Tuesday night into Wednesday. Its northward extent and longevity is all dependent on the strength of the system, and NAM featuring a closed low and large deformation zone, has the greatest northward push and keeps precipitation well into Wednesday night. Regardless the precipitation and accompanying overcast low clouds will keep temperatures well below average on Wednesday. We could continue to see a periodic shower threat through the end of the week as we get into deeper cyclonic flow on the backside of the slow-moving deep upper trof. Temperatures will remain below average into at least Friday. Glass && .AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1227 PM CDT Mon May 12 2014 Specifics for KSTL, KSUS, KCPS, KUIN, KCOU: An approaching cold front will likely bring a period of SHRA/TSRA to all TAF sites during the late afternoon and evening. A stray shower or thunderstorm is possible early this afternoon, but the main precipitation threat is with the front. A broad area of MVFR cigs is located behind the front, and these clouds will remain over the terminals even after the front has moved eastward and precipitation has ended. Initially south to southwest winds will become northwesterly after fropa. Kanofsky && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
329 PM CDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 329 PM CDT MON MAY 12 2014 MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE WINDS ACROSS THE AREA THROUGH THE REMAINDER OF THE AFTERNOON...PRECIPITATION ENDING IN THE EAST THIS EVENING AND OVERNIGHT TEMPERATURES. CURRENTLY...SURFACE LOW PRESSURE OVER SOUTHEAST MINNESOTA WITH AN INVERTED TROUGH NORTH THROUGH NORTHERN MINNESOTA. THE DEFORMATION ZONE ASSOCIATED WITH THIS LOW PRESSURE SYSTEM WILL CONTINUE TO TRACK EAST THIS EVENING AND RAIN SHOWERS WILL END OVER THE JAMES RIVER VALLEY THIS EVENING. LATEST RAP SOUNDINGS INDICATE THAT AREAS ALONG AND WEST OF HIGHWAY 83 WILL SEE DIMINISHING WINDS THIS EVENING. IT MAY BE BREEZY THROUGH AROUND 9 PM BUT WINDS SHOULD REMAIN BELOW ADVISORY LEVELS. WINDS COULD HOLD ON OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA WITH KJMS AND CARRINGTON 19 UTC BUFR SOUNDINGS INDICATING THE BOUNDARY LAYER REMAINING LIFTED WITH 40 KNOT WINDS AVAILABLE TO WORK DOWN. GRADIENT WINDS WILL BE STRONGEST HERE ALSO...CLOSER TO THE SURFACE LOW. WILL KEEP THE ADVISORY GOING AND EVENING SHIFT WILL NEED TO LOOK INTO POSSIBLY EXTENDING EASTERN PORTIONS OF THE ADVISORY. CONVECTIVE CUMULUS FLATTENING OUT SHOULD SLOWLY DISSIPATE THIS EVENING. THUS MOSTLY CLEAR SKIES ARE EXPECTED BY MORNING. WILL SEE LOWS IN THE LOW TO MID 30S MOST AREAS. WINDS SHOULD REMAIN AT 5 TO 10 MPH OVERNIGHT...KEEPING TEMPERATURES FROM FALLING INTO THE 20S. MID 30S ARE EXPECTED OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA WHERE WINDS AND CLOUDS HANG ON LONGER TONIGHT. TUESDAY WILL BE MUCH NICER THAN TODAY OVER THE JAMES RIVER VALLEY...WITH NO RAIN...LESS WIND AND MORE SUN. ELSEWHERE...TUESDAY IS EXPECTED TO SIMILAR TO TODAY...BUT WITH A LITTLE LESS CLOUDS AND WINDS AND A LITTLE MORE SUNSHINE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 329 PM CDT MON MAY 12 2014 TROUGH MOVES EAST WEDNESDAY WITH NORTHWEST FLOW ALOFT DEVELOPING AND PERSISTING THROUGH THE FIRST HALF OF NEXT WEEKEND. EMBEDDED WAVE IS DEPICTED TO MOVE THROUGH SOMETIME THURSDAY NIGHT OR FRIDAY BRINGING A CHANCE FOR SHOWERS TO THE LOCAL AREA. OTHERWISE THE REST OF THE WORK WEEK APPEARS MAINLY DRY. 12Z GFS/ECMWF SHOW A SHORT WAVE RIDGE SATURDAY NIGHT FOLLOWED BY A MORE ACTIVE FLOW SUNDAY INTO MONDAY AHEAD AND ALONG A DEVELOPING TROUGH ORIGINATING OVER THE PACIFIC NORTHWEST AND PROGRESSING EASTWARD. MILDER TEMPERATURES OVER THE WEEKEND AS WELL...HELPING TO INCREASE THE POTENTIAL FOR THUNDERSTORMS SUNDAY-MONDAY. UNCERTAINTY STILL HIGH SO WILL LEAVE OUT OF THE FORECAST AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 329 PM CDT MON MAY 12 2014 MVFR CEILINGS WILL CONTINUE THROUGH THE AFTERNOON AT KJMS...WITH CEILINGS EXPECTED TO LIFT ABOVE MVFR MONDAY EVENING. ELSEWHERE VFR CEILINGS ARE EXPECTED THROUGH THE PERIOD. LOW VFR CEILINGS WILL CONTINUE TO LIFT AND DISSIPATE THIS EVENING...BECOMING MOSTLY CLEAR OVERNIGHT. STRONG NORTH WINDS THROUGH THE AFTERNOON WILL DIMINISH TONIGHT AND PICK UP AGAIN ON TUESDAY BUT ARE NOT EXPECTED TO BE AS STRONG...WITH MORE OF A NORTHWEST DIRECTION. WE MAY SEE A PERIOD OF LOW VFR CEILINGS IN CUMULUS EARLY TUESDAY AFTERNOON...JUST BEYOND THE TAF PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NDZ002>005-010>013-018>023-025-031>037-040>048-050-051. && $$ SHORT TERM...TWH LONG TERM...NH AVIATION...TWH
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
109 PM CDT MON MAY 12 2014 .AVIATION... MVFR CONDITIONS ARE EXPECTED FOR THIS FORECAST PERIOD AND WIDESPREAD DISRUPTIONS ARE EXPECTED THIS AFTERNOON AND EVENING DUE TO THUNDERSTORM ACTIVITY AFFECTING THE AREA. A COLD FRONT CONTINUES TO APPROACH FROM THE NORTHWEST. AT 1730Z... THE FRONT WAS LOCATED ALONG A LINE FROM JACKSBORO TO JUST WEST OF COMANCHE AND WAS MOVING EAST AROUND 14KTS. HOWEVER... THE SPEED OF THE FRONT MAY INCREASE DEPENDING ON THE INTENSITY OF THE CONVECTION ALONG THE BOUNDARY. WINDS WILL CONTINUE TO BE GUSTY BUT WILL SHIFT TO THE NORTH BEHIND THE FRONT. STORMS HAVE ALREADY BEGUN TO DEVELOP ALONG THE FRONT BUT CONVECTION WILL LIKELY AFFECT AREAS AHEAD OF THE PRIMARY WIND SHIFT. CONVECTION WILL BEGIN TO AFFECT DFW TAF SITES AROUND 20Z AND WACO AROUND 22Z. SOME OF THE STORMS MAY BE MARGINALLY SEVERE WITH A DAMAGING WIND THREAT BEING THE PRIMARY CONCERN. WINDS WILL LIKELY SHIFT TO THE NORTHWEST WITH CONVECTION ALONG THE FRONT. AMENDMENTS WILL LIKELY BE REQUIRED OVER THE NEXT COUPLE OF HOURS AS CONVECTION MOVES EAST TO ADDRESS WINDS/TIMING OF TSTMS. WHILE MVFR CONDITIONS ARE FORECAST...IFR VIS MAY BRIEFLY AFFECT TAF SITES DURING CONVECTION. IT WAS NOTED DURING THE MORNING CONVECTION THAT AFFECTED THE DFW METRO TAF SITES THAT THE RAINFALL APPEARED LIGHT ON RADAR...BUT RESULTED IN LOW VIS AND HIGHER RAINFALL AMOUNTS THAN EXPECTED. && .UPDATE... CURRENT FORECAST IS IN GOOD SHAPE AND HAVE ONLY MADE SOME COSMETIC CHANGES TO THE HOURLY DATA AND MORNING POPS. LATEST SURFACE ANALYSIS INDICATES THAT THE COLD FRONT IS LOCATED ALONG A LINE ACROSS CENTRAL OKLAHOMA INTO NORTHWEST TEXAS BETWEEN BOWIE AND WICHITA FALLS SOUTHWARD TO BRECKENRIDGE. AHEAD OF THE COLD FRONT AN AREA OF SHOWERS AND THUNDERSTORMS INITIATED ON WHAT APPEARS TO BE AN INITIAL WAVE OF FORCING OR A SOUTHWARD PROPAGATING GRAVITY WAVE. EITHER WAY...AMDAR SOUNDING DATA FROM DFW AIRCRAFT INDICATE THAT STRONG CAPPING INVERSION NOTED ON 12Z FWD SOUNDING WAS ALL BUT COMPLETELY ERODED IN ABOUT 45 MINUTES. THIS INITIAL WAVE OF ACTIVITY HAS FAILED TO ORGANIZE OR REALLY TAKE OFF IN INTENSITY WHICH HAS LEFT THE LOW LEVEL WINDS AND MOISTURE IN PLACE BEHIND IT. THIS WILL LIKELY HELP TO INITIATE MORE ROBUST THUNDERSTORM ACTIVITY OVER THE NEXT FEW HOURS AS THE FRONT CONTINUES TO MOVE SOUTH. LATEST OBJECTIVE ANALYSIS ACROSS NORTH TEXAS SHOWS AROUND 2000 J/KG OF SURFACE BASED INSTABILITY SOUTH/EAST OF THE FRONT WHERE THE SUN HAS COME OUT A BIT WITH LITTLE INHIBITION LEFT. EXPECT THUNDERSTORMS TO BECOME MORE NUMEROUS IN COVERAGE THROUGH EARLY AFTERNOON. THE SEVERE THREAT REMAINS ACROSS NORTH TEXAS...ESPECIALLY GIVEN THE STRONG INSTABILITY...HOWEVER DEEP LAYER SHEAR ISNT ALL THAT STRONG SO MULTICELL CLUSTERS ARE EXPECTED. SOME SEVERE WIND GUSTS WOULD BE POSSIBLE ALONG WITH SEVERE HAIL. THE MORE SIGNIFICANT THREAT WILL BE FOR VERY HEAVY RAINFALL AND FLASH FLOODING...ESPECIALLY ACROSS THE EASTERN COUNTIES WHERE THE FRONT IS EXPECTED TO SLOWLY MOVE THROUGH TONIGHT. SOME AREAS COULD PICK UP IN EXCESS OF 3 INCHES OF RAIN IN A SHORT PERIOD OF TIME WITH ADDITIONAL RAINFALL PERSISTING INTO TONIGHT. DUNN && .PREV DISCUSSION... /ISSUED 437 AM CDT MON MAY 12 2014/ THE POTENT UPPER LEVEL LOW OVER THE FOUR CORNERS THAT WAS RESPONSIBLE FOR SNOW IN DENVER YESTERDAY WILL EJECT NORTHEAST OUT INTO THE PLAINS TODAY...BUT ADDITIONAL UPPER ENERGY WILL DROP INTO THE BASE OF A DEEPENING LONGWAVE TROUGH TODAY. THIS UPPER TROUGH WILL ENGULF THE CENTRAL US BY TOMORROW...A PATTERN THAT IS VERY UNUSUAL FOR MID MAY. THIS SYSTEM HAS TAPPED INTO A CANADIAN AIRMASS AND HAS SENT AN UNSEASONABLY STRONG COLD FRONT BARRELING SOUTH. AT 4AM...THIS FRONT WAS LOCATED JUST SOUTH OF LUBBOCK TO NEAR VERNON TO EL RENO OKLAHOMA AND WAS MOVING SOUTHEAST AT 15 TO 20MPH. THE FRONT IS AHEAD OF MOST MODEL PROJECTIONS...WHICH IS NOT SURPRISING GIVEN THE COLD AIR BEHIND IT. THE RAP HAS A GOOD HANDLE ON THE FRONT/S SPEED AND IT WILL BE USED FOR TIMING. THE FRONT WILL ARRIVE INTO THE NORTHWEST CWA BY MID-MORNING AND CONTINUE TO TRACK SOUTHEAST...BUT SLOW DOWN A BIT DUE TO DAYTIME HEATING. THE FRONT SHOULD REACH A SHERMAN TO DFW TO COMANCHE LINE BY MID-AFTERNOON. THE AIRMASS AHEAD OF THE FRONT WILL BE WARM AND MOIST...WITH SEVERAL DAYS OF SOUTHERLY FLOW NOW BRINGING PRECIPITABLE WATER VALUES UP TO 1.75 TO 2 INCHES. SURFACE BASED CAPE WILL PEAK AROUND 2000-2500 J/KG THIS AFTERNOON AS TEMPS WARM INTO THE MID 80S. DAYTIME HEATING AND FORCING FOR ASCENT FROM THE UPPER LEVEL TROUGH WILL LIFT/ERODE THE WEAK CAPPING INVERSION...AND THUS CONVECTION WILL INCREASE IN COVERAGE ALONG THE FRONT BY LATE MORNING. BULK LAYER SHEAR IS FAIRLY WEAK...ON THE ORDER OF 25KT...SO MULTICELLULAR CONVECTIVE MODES ARE EXPECTED. GIVEN THE HIGH INSTABILITY AND WEAK SHEAR...SOME SEVERE WIND/HAIL REPORTS ARE POSSIBLE TODAY WITH THE STRONGEST STORMS. CONVECTION ALONG THE FRONT WILL LIKELY CONGEAL INTO A SOLID LINE OF THUNDERSTORMS BY MID-AFTERNOON...WITH THE LINE CONTINUING TO GROW UPSCALE INTO A FORMIDABLE LINEAR MCS BY THE EVENING HOURS. MCS PROPAGATION VECTORS AND DIFFLUENT THICKNESS FIELDS ALOFT SUGGEST THAT THE MOVEMENT OF THIS SYSTEM WILL REMAIN FAIRLY SLOW...LIKELY LESS THAN 10-15MPH. THIS FORWARD SPEED SHOULD IN THEORY LIMIT THE DAMAGING WIND THREAT THIS EVENING OVER THE SOUTHEAST HALF OF THE CWA...BUT WILL RESULT IN ENHANCED RAINFALL TOTALS. THE MCS WILL LIKELY HAVE SLOWER WEST TO EAST MOVEMENT THAN NORTH TO SOUTH...AND THUS THE ORIENTATION OF THE LINE SUGGESTS THAT EASTERN ZONES WILL HAVE A GREATER RISK FOR PROLONGED HEAVY RAINFALL. EXPECT THE LINE TO PUSH THROUGH THE SOUTHWEST ZONES FAIRLY QUICKLY...LIKELY REACHING A LAMPASAS TO WACO LINE BY 6 PM. A TIGHT RAINFALL GRADIENT IS FORECAST OVER THE CWA WITH LESS THAN A HALF INCH EXPECTED OVER THE NW ZONES...TO 1-2 INCHES IN A BAND FROM THE SHERMAN AREA TO THE METROPLEX TO COMANCHE...AND 2-3 INCHES SOUTH AND EAST OF A PARIS TO GREENVILLE TO HILLSBORO LINE. THIS LATTER REGION WAS THE SAME AREA THAT RECEIVED A SWATH OF 2-4 INCHES OF RAIN THURSDAY AND SOILS ARE ALREADY SATURATED. THUS A FLASH FLOOD WATCH WAS ISSUED FOR LOCATIONS ALONG AND SOUTHEAST OF A BONHAM TO DALLAS TO TEMPLE LINE. WHILE WE DONT EXPECT MOST OF DALLAS AND COLLIN COUNTIES TO RECEIVE MORE THAN 2 INCHES...GIVEN THE URBAN DEVELOPMENT THERE AND THE FACT THAT THE SOUTHEAST PARTS OF THESE COUNTIES DID SEE OVER 4 INCHES...FELT IT WAS BEST TO INCLUDE THEM. FARTHER SOUTH...FROM WACO TO ATHENS...LESS RAIN FELL IN THIS AREA LAST THURSDAY...BUT QUICK TOTALS OF 2-3 INCHES ARE POSSIBLE THIS EVENING. FOR WACO/TEMPLE/KILLEEN ONLY AROUND 2 INCHES ARE FORECAST...BUT AGAIN URBAN INFRASTRUCTURE MAY EXACERBATE ANY FLOODING...SO THEY WERE INCLUDED IN THE WATCH TOO. BECAUSE THE UPPER LEVEL TROUGH WILL BE SLOW TO MOVE EAST...CONTINUED SOUTHERLY FLOW ALOFT BEHIND THE FRONT/LINE OF STORMS WILL OCCUR THIS EVENING. THUS THE LINE OF STORMS WILL LIKELY BE SUCCEEDED BY A FEW HOURS OF STEADY LIGHT TO MODERATE STRATIFORM RAINS...ESPECIALLY ACROSS THE WATCH AREA. THIS ACTIVITY SHOULD END FROM NORTHWEST TO SOUTHEAST LATE TONIGHT...BUT MAY LINGER OVER THE SOUTHEAST ZONES INTO TUESDAY MORNING. TUESDAY SHOULD BE DRY FOR THE REMAINDER OF THE AREA WITH MOSTLY CLOUDY AND COOL CONDITIONS AS COOLER AIR POURS INTO THE REGION BEHIND THE FRONT. FORECAST HIGH TEMPS MAY BE TOO WARM...BUT IT WOULD ONLY TAKE AN HOUR OR TWO OF AFTERNOON MAY SUNSHINE TO WARM US INTO THE MID 60S...SO STAYED CONSERVATIVE THERE. THE STRONGEST UPPER LEVEL FORCING WILL CROSS THE REGION TUESDAY EVENING BUT THE AIRMASS WILL BE PRETTY WORKED OVER. HOWEVER THIS FORCING SHOULD RESULT IN SCATTERED ELEVATED SHOWERS AND A FEW STORMS OVER THE REGION AND SHOULD SQUEEZE OUT ANOTHER TENTH TO QUARTER INCH OF RAINFALL. HAVE BUMPED POPS UP TUESDAY NIGHT AS MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT ON THIS ROUND. OTHERWISE THE REMAINDER OF THE FORECAST LOOKS QUIET AND VERY NICE FOR MID TO LATE MAY. DRY NORTHWESTERLY FLOW ALOFT WILL PREVAIL THROUGH THE WEEKEND LEADING TO CLEAR SKIES AND LIGHT WINDS. GOOD RADIATIONAL COOLING WEDNESDAY NIGHT WILL SEND LOW TEMPS DOWN INTO THE 40S AREA WIDE...AND WACO MAY BREAK ITS RECORD LOW OF 46. HIGHS IN THE UPPER 60S ARE EXPECTED THURSDAY...BUT TEMPS SHOULD WARM INTO THE 70S FRIDAY AND THE 80S BY THE WEEKEND. DRY WEATHER WILL CONTINUE INTO NEXT WEEK WITH TEMPS WARMING TO ABOVE NORMAL. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 83 54 66 51 68 / 90 80 20 40 10 WACO, TX 87 57 65 51 69 / 70 100 40 60 10 PARIS, TX 84 56 63 51 64 / 70 90 20 50 20 DENTON, TX 80 52 65 49 68 / 80 70 20 40 10 MCKINNEY, TX 83 53 64 50 68 / 90 80 20 40 10 DALLAS, TX 84 55 65 52 68 / 90 80 20 50 10 TERRELL, TX 85 57 64 51 67 / 70 90 20 50 20 CORSICANA, TX 86 59 64 52 67 / 60 100 40 60 20 TEMPLE, TX 87 58 64 52 69 / 50 100 50 60 10 MINERAL WELLS, TX 80 50 66 47 71 / 70 60 20 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH LATE TONIGHT FOR TXZ094-095-104>107-119>123-134-135-145>148-158>162- 174-175. && $$ /
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1250 PM CDT MON MAY 12 2014 .AVIATION... /18Z TAFS/ A cold front has moved into the southeast half of the CWA this afternoon, with showers and thunderstorms developing in the warm sector. The greatest threat for thunderstorms will be from the KBWD, to KBBD, to KJCT terminals. VCTS remarks were included through early evening in these areas with winds eventually shifting to the northwest as the front moves slowly south. Behind the front, winds will remain from the northwest at near 15 kts, gusting up to 25 kts at times. MVFR ceilings will continue for a bit longer at KABI but VFR conditions will persist at KSJT. More widespread rain will be possible over the southeast terminals overnight, mainly at KJCT. The NAM model is suggesting very low clouds continuing across the southeast through the period but the GFS looks more reasonable, keeping prevailing ceilings above 3000 ft. Johnson && .PREV DISCUSSION... /ISSUED 1131 AM CDT MON MAY 12 2014/ UPDATE... The cold front is just a bit ahead of schedule, currently bifurcating the CWA from southwest to northeast (Ozona, to Paint Rock, to Cross Plains). Winds are from the north at 15-20 mph in the wake of this front. Temperatures remain in the 60s in areas that experienced the frontal passage early this morning, but have only regressed into the mid 70s at locations where the front as arrived in the past 1-2 hours. I lowered max temps across the Big Country and western Concho Valley a few degrees with only minor tweaks needed elsewhere. Other minor changes were made to the dewpoint/wind grids to account for the faster cold front. Convection is just now beginning to ramp up in the warm sector, primarily from Paint Rock to Brownwood. The EMC RAP meso-analysis provided by the SPC indicates MLCAPE values of 2000-3000 J/kg across the area with little/no CINH. Effective shear has increased over the past few hours and should be supportive of organized convection this afternoon and early this evening. Steep mid-level lapse rates will promote hail growth, however, the drier air behind this front may push the severe threat east of the area by early evening. During the late afternoon and evening hours, this convection should grow upscale, decreasing the severe threat and becoming more of a heavy rain producer. PREV DISCUSSION... /ISSUED 634 AM CDT MON MAY 12 2014/ AVIATION... /12Z TAFS/ Stratus will remain over the Heartland and Northwest Hill Country through mid morning and then will dissipate. Going with MVFR CIGS at the KJCT and KBBD terminals until 16Z. Mainly VFR conditions are expected the rest of the TAF forecast. Isolated to scattered thunderstorms will be possible east of an Abilene to San Angelo line mainly this afternoon and tonight. Storms may even be more numerous by tonight east of a Coleman to Junction line. The models are developing an MCS along a cold front by 06Z Tuesday and moving it slowly east into central Texas. However, confidence is only high enough to add VCTS to the terminals through 02Z Tuesday. Winds will be south and then become north as cold front moves through West Central Texas today and this evening. PREV DISCUSSION... /ISSUED 442 AM CDT MON MAY 12 2014/ SHORT TERM... (Today and Tonight) WV imagery this morning was showing and a strong upper level trough over the central and southern Rockies with a mid level speed max of 50 to 70 knots rotating out in the Plains. Upper level flow has backed to southwest over Texas. Also, a lot mid and upper subsidence evident which is still resulting in a strong cap over West Central Texas. At the surface, a cold front was located along a Quanah to Seminole line. A dryline extended south along a Wink to Sanderson line. Not much happening yet convection wise as low level inhibition and cap is still holding strong. A few showers have developed just behind the cold front across northwest Texas. The airmass was very moist across our area with southerly flow and dewpoints in the mid to upper 60s. For today, the chance of showers and thunderstorms will increase mid morning through the afternoon across mainly the eastern half of the CWFA. The cold front will continue southeast into West Central Texas and will probably slow its forward speed. Scattered showers and thunderstorms will develop along and behind the front as elevated instability erases the cap. The HRRR convective allowing model is showing best coverage of activity east of an Abilene to San Angelo line. The combination of good instability in the warm sector and weak 0-6KM shear of 25 to 30 knots will result in multicell storms with possible brief supercell structures. A few strong to severe storms are possible across mainly the Heartland and Northwest Hill Country. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning. Going with mainly chance to slight chance POPS for today. Temperatures will be cooler with highs in the 80s. For tonight, There will be a chance of showers thunderstorms across much of our area with better coverage of storms east of a Coleman to Sonora line. a few storms may be severe. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning mainly before 06Z Tuesday. The bigger focus will be the potential for locally heavy rainfall across the Heartland and Northwest Hill Country, due to good low level southerly flow. moisture flux convergence along a slow moving cold front, PWAT values of 1.5 to 1.75 inches and in the RRQ of highly amplified 250MB jet. Rainfall amounts of 1 to 2 inches with locally heavy amounts are possible along and east of a Brownwood to Junction line. Also, going with LKLY to CAT POPS across the southeast CWFA. LONG TERM... (Tuesday through next Monday) The cold front will be well south of the area early Tuesday morning, with the upper level trough axis over New Mexico. Showers and thunderstorms may be ongoing across far southeast sections early Tuesday morning but will move east of the area by mid to late morning. Additional showers and isolated thunderstorms will be possible across much of the area during the day as lift increases ahead of the approaching upper trough. Moisture will be limited, so precipitation is expected to be light, with most areas seeing one tenth inch or less of rainfall. It will be considerably cooler on Tuesday with highs well below normal for this time of year. NAM guidance looks too cool with highs in the upper 50s, so went with a GFS/NAM blend, which looks more reasonable with highs topping out in the lower 60s. Lingering showers will be possible Tuesday evening over southeast sections, otherwise dry conditions are expected overnight with clearing skies, as drier air filters in behind the departing upper trough. Temperatures will be very chilly Wednesday night with overnight lows in the lower and middle 40s. Dry and cool weather will continue on Wednesday with sunny skies, light winds and highs in the lower 70s. Another cool night is in store Wednesday night with low temperatures again in the 40s. Will maintain a dry forecast Thursday into next weekend with a warming trend through the period. Northwest flow aloft is expected through Saturday, with a short wave ridge overspreading the Plains on Sunday. High temperatures will warm from the mid 80s late week, to the upper 80s and lower 90s by the end of the weekend. Expect overnight lows in the 50s, warming into the 60s through the period. FIRE WEATHER... Elevated fire weather conditions will be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 50 63 44 71 45 / 20 20 10 0 0 San Angelo 52 62 42 72 42 / 20 20 10 0 0 Junction 57 64 46 72 41 / 70 40 20 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ Aviation: Johnson
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1131 AM CDT MON MAY 12 2014 .UPDATE... The cold front is just a bit ahead of schedule, currently bifurcating the CWA from southwest to northeast (Ozona, to Paint Rock, to Cross Plains). Winds are from the north at 15-20 mph in the wake of this front. Temperatures remain in the 60s in areas that experienced the frontal passage early this morning, but have only regressed into the mid 70s at locations where the front as arrived in the past 1-2 hours. I lowered max temps across the Big Country and western Concho Valley a few degrees with only minor tweaks needed elsewhere. Other minor changes were made to the dewpoint/wind grids to account for the faster cold front. Convection is just now beginning to ramp up in the warm sector, primarily from Paint Rock to Brownwood. The EMC RAP meso-analysis provided by the SPC indicates MLCAPE values of 2000-3000 J/kg across the area with little/no CINH. Effective shear has increased over the past few hours and should be supportive of organized convection this afternoon and early this evening. Steep mid-level lapse rates will promote hail growth, however, the drier air behind this front may push the severe threat east of the area by early evening. During the late afternoon and evening hours, this convection should grow upscale, decreasing the severe threat and becoming more of a heavy rain producer. && .PREV DISCUSSION... /ISSUED 634 AM CDT MON MAY 12 2014/ AVIATION... /12Z TAFS/ Stratus will remain over the Heartland and Northwest Hill Country through mid morning and then will dissipate. Going with MVFR CIGS at the KJCT and KBBD terminals until 16Z. Mainly VFR conditions are expected the rest of the TAF forecast. Isolated to scattered thunderstorms will be possible east of an Abilene to San Angelo line mainly this afternoon and tonight. Storms may even be more numerous by tonight east of a Coleman to Junction line. The models are developing an MCS along a cold front by 06Z Tuesday and moving it slowly east into central Texas. However, confidence is only high enough to add VCTS to the terminals through 02Z Tuesday. Winds will be south and then become north as cold front moves through West Central Texas today and this evening. PREV DISCUSSION... /ISSUED 442 AM CDT MON MAY 12 2014/ SHORT TERM... (Today and Tonight) WV imagery this morning was showing and a strong upper level trough over the central and southern Rockies with a mid level speed max of 50 to 70 knots rotating out in the Plains. Upper level flow has backed to southwest over Texas. Also, a lot mid and upper subsidence evident which is still resulting in a strong cap over West Central Texas. At the surface, a cold front was located along a Quanah to Seminole line. A dryline extended south along a Wink to Sanderson line. Not much happening yet convection wise as low level inhibition and cap is still holding strong. A few showers have developed just behind the cold front across northwest Texas. The airmass was very moist across our area with southerly flow and dewpoints in the mid to upper 60s. For today, the chance of showers and thunderstorms will increase mid morning through the afternoon across mainly the eastern half of the CWFA. The cold front will continue southeast into West Central Texas and will probably slow its forward speed. Scattered showers and thunderstorms will develop along and behind the front as elevated instability erases the cap. The HRRR convective allowing model is showing best coverage of activity east of an Abilene to San Angelo line. The combination of good instability in the warm sector and weak 0-6KM shear of 25 to 30 knots will result in multicell storms with possible brief supercell structures. A few strong to severe storms are possible across mainly the Heartland and Northwest Hill Country. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning. Going with mainly chance to slight chance POPS for today. Temperatures will be cooler with highs in the 80s. For tonight, There will be a chance of showers thunderstorms across much of our area with better coverage of storms east of a Coleman to Sonora line. a few storms may be severe. The main hazards will be large hail, damaging winds and dangerous cloud to ground lightning mainly before 06Z Tuesday. The bigger focus will be the potential for locally heavy rainfall across the Heartland and Northwest Hill Country, due to good low level southerly flow. moisture flux convergence along a slow moving cold front, PWAT values of 1.5 to 1.75 inches and in the RRQ of highly amplified 250MB jet. Rainfall amounts of 1 to 2 inches with locally heavy amounts are possible along and east of a Brownwood to Junction line. Also, going with LKLY to CAT POPS across the southeast CWFA. LONG TERM... (Tuesday through next Monday) The cold front will be well south of the area early Tuesday morning, with the upper level trough axis over New Mexico. Showers and thunderstorms may be ongoing across far southeast sections early Tuesday morning but will move east of the area by mid to late morning. Additional showers and isolated thunderstorms will be possible across much of the area during the day as lift increases ahead of the approaching upper trough. Moisture will be limited, so precipitation is expected to be light, with most areas seeing one tenth inch or less of rainfall. It will be considerably cooler on Tuesday with highs well below normal for this time of year. NAM guidance looks too cool with highs in the upper 50s, so went with a GFS/NAM blend, which looks more reasonable with highs topping out in the lower 60s. Lingering showers will be possible Tuesday evening over southeast sections, otherwise dry conditions are expected overnight with clearing skies, as drier air filters in behind the departing upper trough. Temperatures will be very chilly Wednesday night with overnight lows in the lower and middle 40s. Dry and cool weather will continue on Wednesday with sunny skies, light winds and highs in the lower 70s. Another cool night is in store Wednesday night with low temperatures again in the 40s. Will maintain a dry forecast Thursday into next weekend with a warming trend through the period. Northwest flow aloft is expected through Saturday, with a short wave ridge overspreading the Plains on Sunday. High temperatures will warm from the mid 80s late week, to the upper 80s and lower 90s by the end of the weekend. Expect overnight lows in the 50s, warming into the 60s through the period. FIRE WEATHER... Elevated fire weather conditions will be possible across much of West Central Texas Wednesday through Friday, as minimum relative humidity values drop to 15 to 20 percent, but 20 foot winds generally remain below 15 mph. && .PRELIMINARY POINT TEMPS/POPS... Abilene 76 50 63 45 72 / 40 20 20 10 0 San Angelo 85 52 62 43 73 / 20 20 20 10 0 Junction 84 57 64 46 73 / 30 70 40 20 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ Update: Johnson
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
328 PM CDT MON MAY 12 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 328 PM CDT MON MAY 12 2014 FOCUS OF THE FORECAST IS ON THE RAIN CHANCES AND IMPACTS TONIGHT. LATEST SURFACE ANALYSIS SUGGESTS THE INVERTED TROUGH/COLD FRONT EXTENDS FROM NORTHWEST WISCONSIN INTO WESTERN WISCONSIN. HARD TO DEFINE A COMPACT AREA OF LOW PRESSURE BUT LOOKS TO BE MORE OF AN ELONGATED FEATURE ALONG THE TROUGH/FRONT FROM SOUTHEAST MINNESOTA ACROSS MUCH OF IOWA. A WARM FRONT LOOKED TO EXTEND ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS...ROUGHLY ALONG THE HIGHWAY 20 CORRIDOR. LOCAL AND REGIONAL RADARS SHOWING A LINE OF CONVECTION ALONG THE COLD FRONT FROM NORTHEAST IOWA INTO WESTERN MISSOURI/EASTERN KANSAS. LATEST ANALYSIS INDICATES AROUND 500 J/KG OF SB CAPE WAS ALONG INTERSTATE 90 BUT THIS INCREASED TO ALMOST 2000 J/KG ALONG THE SOUTHERN BORDER OF THE FORECAST AREA. THE 12.18Z RAP SUGGESTS THESE HIGHER CAPE VALUES WILL SPREAD ACROSS THE EASTERN PARTS OF THE FORECAST AREA THROUGH THE REST OF THE AFTERNOON INTO THE EARLY EVENING. THE RAP BUFKIT SOUNDINGS STILL SUGGESTS THIS IS PRIMARILY A TALL SKINNY CAPE PROFILE WHICH WOULD SUGGEST THAT LARGE HAIL MAY NOT BE MUCH OF A THREAT. FOR ANY STORMS THAT GET INTO THE AREA AND CAN ORIENT WITH THE 0-3KM SHEAR VECTORS...DAMAGING WIND WILL BE POSSIBLE. CANNOT TOTALLY RULE OUT AN ISOLATED TORNADO AS THE WARM FRONT MOVES INTO THE AREA...BUT BECAUSE OF THE ELONGATED SURFACE LOW...NOT REALLY SEEING ANY LOCALIZED BACKING OF THE WINDS TO ENHANCE THE LOW LEVEL HELICITY. CURRENTLY EXPECTING THE LINE OF ACTIVITY ACROSS IOWA INTO MISSOURI TO CONTINUE TRANSLATING NORTHEAST AHEAD OF THE TROUGH/FRONT AND PRIMARILY AFFECTING THE EASTERN SECTIONS OF THE FORECAST AREA FROM NORTHEAST IOWA INTO CENTRAL WISCONSIN. HAVE LINED UP THE RAIN CHANCES WITH 80 PERCENT OVER THIS AREA TRAILING BACK TO ABOUT A 40 PERCENT CHANCE ACROSS THE WEST. AS THE TROUGH/COLD FRONT ADVANCES SLOWLY EAST TONIGHT...THE RAIN CHANCES WILL ESSENTIALLY END FROM WEST TO EAST AND EXPECT THE ENTIRE AREA TO BE DRY BY 12Z TUESDAY. AFTER TONIGHT...SOME SMALL RAIN CHANCES RETURN TO THE SOUTHEAST PARTS OF THE FORECAST AREA WEDNESDAY NIGHT. THE MEAN LONG WAVE TROUGH WILL REMAIN OVER THE CENTRAL PART OF THE COUNTRY THANKS TO AN UPPER LEVEL LOW NEAR HUDSON BAY AND ANOTHER SHORT WAVE TROUGH COMING OUT OF THE SOUTHWEST PART OF THE COUNTRY. THIS SHORT WAVE TROUGH IS EXPECTED TO PASS OFF JUST TO THE SOUTHEAST OF THE AREA ACROSS ILLINOIS WITH THE SURFACE LOW NEAR THE OHIO RIVER. THE DEFORMATION AREA OF RAIN ON THE NORTHWEST SIDE OF THE LOW COULD EXTEND BACK INTO THE AREA AND WILL HAVE THE SMALL RAIN CHANCES FOR THIS POSSIBILITY. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 328 PM CDT MON MAY 12 2014 THE LONG WAVE TROUGH WILL THEN MOVE SLOWLY NORTHEAST AS SEVERAL WEAKER SHORT WAVE TROUGHS COME INTO THE LONG WAVE TROUGH ON THE NORTHWEST FLOW FROM SOUTHERN AND WESTERN CANADA. THIS WILL PROVIDE JUST ENOUGH FORCING FOR SOME SMALL RAIN CHANCES THURSDAY THROUGH FRIDAY...SATURDAY AND AGAIN MONDAY. TEMPERATURES WILL STILL BE COOL TO CLOSE OUT THE WEEK BUT THEN START TO MODERATE FOR THE WEEKEND INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1247 PM CDT MON MAY 12 2014 MUCH OF THE AREA TO GET A BREAK FROM THE SHRA/TSRA DURING THE EARLY AFTERNOON HOURS. A SFC TROUGH/FRONT WILL SLIDE EAST INTO AND ACROSS THE TAF SITES LATER THIS AFTERNOON/EARLY THIS EVENING. ONE MORE ROUND OF SHRA/TSRA EXPECTED TO DEVELOP ALONG/AHEAD OF THIS BOUNDARY AND IMPACT THE TAF SITES MAINLY IN THE 20Z-01Z PERIOD THIS AFTERNOON/EARLY THIS EVENING. SHRA/TSRA WITH MVFR/IFR CIGS/VSBYS TO BE MORE OF AN IMPACT AT KLSE VS. KRST...CARRIED A PERIOD OF TEMPO TSRA AT KLSE AND ONLY VCTS/CB AT KRST DURING THIS TIME-FRAME. ONCE THE TROUGH/FRONT PUSHES THRU...CONCERN SHIFTS TO THE ABUNDANT LOW LEVEL MOISTURE AND IFR/LIFR CIGS BEHIND IT WHICH WILL SPREAD ACROSS THE TAF SITES FOR MUCH OF TONIGHT INTO TUE MORNING. A PERIOD OF MVFR VSBYS IN BR EXPECTED AS WELL. EVENTUALLY THE BRISK NORTHWEST WINDS/LOW LEVEL FLOW WILL SPREAD/MIX SOME DRIER BOUNDARY LAYER AIR INTO THE AREA WITH VSBYS EXPECTED TO IMPROVE TO VFR AND CIGS TO IMPROVE TO MVFR THRU TUE MORNING. && .HYDROLOGY... ISSUED AT 328 PM CDT MON MAY 12 2014 AS THE STORMS COME IN ACROSS THE EASTERN SECTIONS TONIGHT...THE TALL SKINNY CAPE PROFILE SHOULD LEAD TO MORE RAIN DROP PRODUCTION INSTEAD OF HAIL. THIS CAN ALSO BE SEEN IN THE WARM CLOUD DEPTHS...WHICH THE 12.18Z NAM CONTINUES TO SHOW TO BE AROUND 3500 METERS. WHILE THE QPF THAT FALLS THROUGH THE REST OF THE AFTERNOON AND EVENING MAY BE AN INCH OR LESS...IT WILL BE FALLING ON GROUND THAT RECEIVED UP TO 1.5 INCHES SUNDAY NIGHT. WITH THE GROUND BEING SATURATED FROM THESE PREVIOUS RAINS...THE ADDITIONAL RAIN COULD STILL PRODUCE SOME LOCALIZED FLOODING PROBLEMS AND WILL CONTINUE THE FLASH FLOOD WATCH FOR ALL BUT THE FAR NORTHWEST SECTION OF THE FORECAST AREA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH UNTIL 1 AM CDT TUESDAY FOR WIZ017-029-032>034- 041>044-053>055-061. MN...FLASH FLOOD WATCH UNTIL 1 AM CDT TUESDAY FOR MNZ088-095-096. IA...FLASH FLOOD WATCH UNTIL 1 AM CDT TUESDAY FOR IAZ009>011-018-019- 029-030. && $$ SHORT TERM...04 LONG TERM...04 AVIATION.....RRS HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
310 PM CDT MON MAY 12 2014 .REST OF THIS AFTERNOON AND TONIGHT - CONFIDENCE...MEDIUM ELONGATED LOW PRESSURE FROM ERN IA INTO WRN WI AREA WILL LIFT TO NORTH OF LAKE SUPERIOR. PLENTY OF MOIST AND UNSTABLE AIR RETURNING. SPC MESO CHARTS ARE SHOWING SOME VERY IMPRESSIVE PARAMETERS ESPECIALLY INTO SC WI. SO HEIGHTENED CONCERN FOR ALL FORMS OF SEVERE WEATHER AND THIS INCLUDES THE POTENTIAL FOR TORNADOGENESIS. OUTFLOW BOUNDARY SETTING UP FAR SRN WI WILL ONLY ADD TO THAT CONCERN. ISOLATED STORMS ALREADY FIRING ACRS NRN IL. 0-6KM SHEAR AND 0-1KM SHEAR GETS A LITTLE BETTER MOVING FROM IL INTO WI. LATEST HRRR SHOWING IA DEVELOPMENT SPREADS ACRS SRN WI LATE AFTN/ERLY EVE WITH LESS CONFIDENCE LATER IN THE NIGHT WITH THE APPROACH OF THE COLD FRONT. AIRMASS MAY BE PRETTY WORKED OVER BY THEN. TWO AREAS RECEIVED DECENT RAINS...ONE BEING IN THE NW CWA NEAR THE DELLS AND THE OTHER IN THE SE. WILL HOLD OFF ON FLASH FLOOD WATCH AS CONVECTION SHOULD BE ON THE MOVE BUT ANY TRAINING ALONG THE OUTFLOW COULD CAUSE PROBLEMS. .TUESDAY - CONFIDENCE...MEDIUM LOW PRESSURE WILL CONTINUE TO LIFT NNE INTO CANADA WITH COLD FRONT SHIFTING TO THE EAST. EXPECT SOME LINGERING SHRA IN ERN CWA DURG THE MRNG HRS. UPPER FLOW IS STILL SOUTHWEST SO THIS WILL LIKELY CARRY SOME WEAK DISTURBANCES ALONG AND AHEAD OF 850 FRONT TO MAINTAIN RAIN CHANCES IN THE MORNING ACROSS THE SE 1/2. THEN WITH THE COLD ADVECTION ON THE BACK SIDE OF THIS SYSTEM WE CAN TAKE ABOUT 10-15 DEGREES OFF THE 925 TEMPS. SO TURNING COOLER...LESS HUMID AND LIKELY A GOOD DEAL OF CLOUD COVER TO CONTEND WITH. LLVL RH PROGS AND MOS SKY COVER SUGGEST THIS... ESPECIALLY WITH THE INCOMING LOW LEVEL COOL POOL AND MID LEVEL TROUGH AXIS STILL TO THE WEST. .TUESDAY NIGHT - CONFIDENCE...HIGH A QUIET PERIOD AS DRY...COOLER AIR SETTLES INTO SOUTHERN WI. 85H TEMPS FALL TO AROUND 0C OVERNIGHT. BOUNDARY LAYER MIXING WILL KEEP THE LOWEST LEVELS STIRRED ENOUGH TO KEEP OVERNIGHT TEMPS MOSTLY 40 TO 45F. .WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE - MEDIUM. UNCERTAINTY CREEPS IN LATER WEDNESDAY THROUGH THURSDAY FOR PRECIP THREAT. SHORT TERM GUIDANCE IN GENERAL AGREEMENT ON CYCLOGENESIS OCCURRING OVER SOUTHERN PLAINS LATER WEDNESDAY WITH STRENGTHENING LOW PRESSURE TRACKING NORTHEAST THROUGH THE TN AND OH VALLEYS. MID- LEVEL CIRCULATION TRACKING ALONG BAROCLINIC ZONE OVER IL MAY BRING SOME -RA TO SOUTHEAST WI WED NGT INTO THU. HOWEVER LATEST CANADIAN A LITTLE FARTHER EAST WITH THE BAROCLINIC ZONE. DUE TO UNCERTAINTY...WL BUMP UP POPS TO HIGH CHANCE IN MY SOUTHEAST...DROPPING OFF FAIRLY QUICKLY TO LOW/SLIGHT CHANCE AS EXPECT A SHARP CUTOFF ACROSS SOUTHEAST WI. LOW LEVEL THERMAL PROFILE FAVORS RAIN...HOWEVER IF SLIGHT ADDITIONAL COOLING WERE TO TAKE PLACE...THEN COULD BE SOME SNOW MIXED IN WITH THE RAIN AT TIMES. .THURSDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE - MEDIUM. LOW MOVING NORTH FROM THE OH VALLEY ACROSS THE GTLAKES THU AND THU NIGHT WILL TRANSITION TO STATIONARY UPPER LOW OVER THE REGION FOR THE END OF THE WEEK...ON INTO THE WEEKEND. THIS WILL RESULT IN CONTINUED PERIOD OF COLD NORTHWEST WINDS REINFORCING CHILLY AIR OVER SRN WI INTO SATURDAY. THE UPPER LOW FINALLY STARTS TO BREAK DOWN OVER THE WEEKEND...WHICH WOULD ALLOW MILDER AIR TO RETURN TO THE AREA BEGINNING SUNDAY. OVERNIGHT LOWS EXPECTED TO DIP INTO THE 30S SEVERAL NIGHTS. WL NEED TO WATCH NIGHT TIME CLOUD COVER AND THINK ABOUT FROST POTENTIAL FOR THURSDAY NIGHT AND FRIDAY NIGHT. && .AVIATION/00Z TAFS/...MAIN SHORT TERM CONCERN WILL BE CONVECTION INTO THE EVENING HOURS. NEXT WAVE OF STORMS APPROACHING FROM IOWA WILL ARRIVE LATER THIS AFTN/EVE. ISOLATED STORMS FIRING VCNTY OUTFLOW BOUNDARY IN NRN IL. THESE MAY BECOME SVR. STORMS IN IA MOVG INTO WI THIS EVE MAY BE SVR AS WELL. LATEST HRRR SUGGESTS LESS ACTIVITY LATER IN THE NIGHT AS AIRMASS STABILIZES ONCE THIS SURGE PASSES. HOWEVER WILL STILL KEEP TSRA CHANCES DUE TO APPROACHING UPPER JET DYNAMICS AND SURFACE COLD FRONT DRAWING CLOSER. DENSE FOG CONCERNS ARE NORTH OF TAF SITES. && .MARINE...WILL RETAIN DENSE FOG ADVISORY THROUGH LATER IN THE NIGHT FOR PORT WASHINGTON TO SHEBOYGAN AS THAT AREA ENTRENCHED IN THE FOGGY CONDITIONS WITH COOL FLOW OFF THE LAKE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...DENSE FOG ADVY LMZ643 TIL 03Z/13. && $$ TONIGHT/TUESDAY AND AVIATION/MARINE...PC TUESDAY NIGHT THROUGH MONDAY...MBK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1119 AM CDT MON MAY 12 2014 .UPDATE...LOTS GOING ON FROM DENSE FOG IN PARTS OF EC WI AND OVER THE LAKE...TO LINE OF STORMS RACING EAST THROUGH SRN WI. SPC MESO PAGE SHOWS DECENT AIRMASS IN PLACE FOR THE STORMS IN NRN IL TO FEED OFF. LOTS OF CLOUDS UPSTREAM SO FURTHER DESTABILIZATION LATER WILL HINGE ON GETTING THINGS CLEARED OFF. BUT BETTER DYNAMICS AND COLD FRONT ARRIVES TONIGHT. LATEST HRRR DOES SHOW MORE CONVECTION ARRIVING TONIGHT WITH SLIGHT RISK STILL IN PLACE. PC && .AVIATION/18Z TAFS/...MAIN SHORT TERM CONCERN WILL BE ONGOING LINE OF STORMS SWEEPING THROUGH SRN WI. DENSE FOG CONCERNS ARE NORTH OF TAF SITES. WILL CLEAR CURRENT STORMS OUT OF THE FAR EAST BY 20Z OR SO THEN WAIT FOR POSSIBLE REDEVELOPMENT THIS EVENING AND OVERNIGHT AS COLD FRONT AND BETTER DYNAMICS GET A BIT CLOSER. PC && .PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 12 2014/ TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH THE UPPER LEVEL RIDGE OVER THE WESTERN GREAT LAKES AHEAD OF THE STRONG WESTERN TROUGH ACROSS THE ROCKIES WILL PUSH INTO THE EASTERN GREAT LAKES BY SUNRISE TUESDAY. THE 105 KNOT JET MAX WAS LIFTING NORTHEAST FROM THE BASE OF THE TROUGH THIS MORNING AND WILL REACH WESTERN MINNESOTA THIS EVENING STRENGTHENING TO 115 KNOTS. WEAK TO MODERATE UPPER DIVERGENCE CONTINUES ACROSS SOUTHERN WISCONSIN TODAY AND TONIGHT. A 700 MB WIND MAX OF 40 KNOTS PUSHES INTO CENTRAL WISCONSIN BY SUNRISE. A SECOND STRONGER 700 MB WIND MAX OF 55 KNOTS ASSOCIATED WITH THE MAIN TROUGH REACHES WESTERN WISCONSIN THIS EVENING AND PUSHES EAST EARLY TUESDAY MORNING. AT 850 MB A 50 KNOT LOW LEVEL JET ACROSS EASTERN KANSAS INTO SOUTHERN IOWA PUSHES INTO SOUTHWEST WISCONSIN JUST AFTER SUNRISE BEFORE WEAKENING AND LIFTING NORTH LATER THIS MORNING. A 45 KNOT 850 MB JET MAX ALSO MOVES ACROSS SOUTHERN WISCONSIN LATE TONIGHT. 700 MB MODERATE UPWARD MOTION OCCURS EARLY THIS MORNING WITH THE APPROACHING LOW LEVEL JET MAX AND 850 MB MOISTURE CONVERGENCE AS THE WARM FRONT ADVANCES NORTH. THEREFORE EXPECT AN AREA OF THUNDERSTORMS TO ROLL THROUGH THIS MORNING. SOME MAY PRODUCE BRIEF HEAVY RAINS. 850/700 MB DEW POINTS INCREASE THIS MORNING WITH 850 MB DEWPOINTS AROUND 11 TO 12 CELSIUS THIS EVENING UNTIL THE CONVECTION OCCURS. BY AFTERNOON SOUTH CENTRAL AND SOUTHEAST WISCONSIN WILL BE IN THE WARM SECTOR. UNTIL THEN EAST TO SOUTHEAST WINDS WILL KEEP THE LAKESHORE AREAS COOL WITH SOME FOG POSSIBLE AS THE AIRMASS DEW POINTS RISE INTO IN THE MID 60S...WITH SOME UPPER 60S POSSIBLE. INLAND AREAS SHOULD REACH 80...BUT AREAS ALONG THE LAKE...ESPECIALLY TOWARD SHEBOYGAN SHOULD STAY COOLER WITH SOUTH/SOUTHEAST FLOW MUCH OF THE DAY. WITH MODELS PRODUCING SOME PRECIPITATION TODAY IN THE WARM SECTOR...THE AMOUNT OF MODEL CAPE IS LIKELY LESS THAN WHAT WILL OCCUR. THERE WILL BE A CHANCE OF THUNDERSTORMS...BUT LIFTING MECHANISM DIFFICULT FOR TIMING DUE TO LIKELY MORNING CONVECTION AND BOUNDARIES. FOCUS FOR SEVERE WILL LIKELY BE IN AREAS WEST OF MADISON EARLY THIS EVENING AHEAD OF THE ADVANCING COLD FRONT. HELICITY VALUES DO RISE TO NEAR 200 WITH SOME LOW LEVEL VEERING. THEREFORE THERE WILL BE A TORNADO THREAT. COLD FRONT THEN MOVES ACROSS SOUTHERN WISCONSIN TONIGHT WITH A LINE OF THUNDERSTORMS EXPECTED. CAPE VALUES WILL DECREASE AS THE STORMS MOVE EAST DUE TO DIURNAL COOLING. LOCAL SEVERE PROBABILITY CWASP VALUES INCREASE TO 75 TO 80 PCT INTO PORTIONS OF SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND EARLY EVENING WITH 70 PCT EAST. TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...MEDIUM THE SURFACE COLD FRONT SHOULD BE THROUGH BY DAYBREAK TUESDAY...WITH A FEW SHOWERS/STORMS POSSIBLY LINGERING EAST IN THE MORNING. IT SHOULD BE DRY THEN THE REST OF THE DAY WITH MUCH COOLER TEMPS BEHIND THE DEPARTING FRONT. DRY WEATHER WILL THEN PERSIST TUESDAY NIGHT THROUGH AT LEAST WEDNESDAY MORNING. LOW PRESSURE PASSING BY WELL TO THE SOUTHEAST MAY BRING SOME LIGHT RAIN THEN LATE WEDNESDAY AFTERNOON INTO THE NIGHT...MAINLY ACROSS THE SOUTHEAST. EVEN COOLER TEMPS ARE LIKELY WEDNESDAY...STRUGGLING INTO THE UPPER 50S MOST PLACES. THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE...MEDIUM NORTHWEST FLOW WILL BRING CONTINUED BELOW NORMAL TEMPERATURES FOR THURSDAY THROUGH THE WEEKEND. A SERIES OF SHORTWAVES WILL ALSO BRING A CHANCE FOR SHOWERS AT TIMES. AVIATION/12Z TAFS/... STILL EXPECTING SOME MVFR CIGS/VSBYS AHEAD OF A WARM FRONT. THE WARM FRONT WILL LIFT NORTH THIS MORNING...BUT SOME SOUTHEAST FLOW MAY STILL AFFECT THE LAKESHORE AREAS OF LAKE MICHIGAN WITH MVFR VSBYS IN FOG/HAZE. EXPECT AN AREA OF THUNDERSTORMS THIS MORNING WITH THE WARM FRONT AND A CHANCE OF THUNDERSTORMS THIS AFTERNOON. THEN MORE THUNDERSTORMS LIKELY WITH A COLD FRONT TONIGHT. SOME OF THE STORMS COULD BE SEVERE...ESPECIALLY THIS AFTERNOON AND EVENING. IFR CONDITIONS IN ANY STORMS. MARINE... LIGHT EAST TO SOUTHEAST WINDS THIS MORNING AHEAD OF AN ADVANCING WARM FRONT WILL BRING AREAS OF FOG. THE WARM FRONT WILL MOVE NORTH LATER TODAY BUT A WEAK ONSHORE FLOW WILL LIKELY CONTINUE NORTH OF MILWAUKEE. LOOK FOR PERIODS OF THUNDERSTORMS TODAY AND TONIGHT. SOME MAY BE SEVERE ESPECIALLY TONIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ052. LM...DENSE FOG ADVISORY UNTIL 2 PM CDT THIS AFTERNOON FOR LMZ643. && $$ TODAY/TONIGHT AND AVIATION/MARINE...HENTZ TUESDAY THROUGH SUNDAY...DDV