Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 04/26/12


AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
430 PM EDT TUE APR 24 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 340 PM EDT TUE APR 24 2012 A WARM FRONT TAKING SHAPE OVER THE PLAINS AND AN UPPER WAVE MOVING IN FROM THE NORTHERN PLAINS SHOULD BRING CHANCES FOR THUNDERSTORMS TO THE AREA WEDNESDAY AFTERNOON AND INTO THURSDAY. BY THURSDAY NIGHT ANOTHER FRONTAL SYSTEM WILL BRING MORE CHANCES TO THE AREA FOR MUCH OF THE WEEKEND BY STALLING THE FRONT AND HAVING SEVERAL WAVES MOVE ALONG IT. BY SUNDAY NIGHT UPPER RIDGING FINALLY STARTS MOVING IN TO DRY THINGS OUT UNTIL TUESDAY. && .NEAR TERM /TONIGHT/... ISSUED AT 340 PM EDT TUE APR 24 2012 RADAR ECHOES ACROSS WESTERN INDIANA AT 19Z ARE NOT PRODUCING ANYTHING BUT VIRGA AT THIS POINT. THOSE OVER ILLINOIS ARE OCCASIONALLY BEING OBSERVED BY ASOS BUT STILL HAVE NOT SEEN ANYTHING MEASURABLE THERE EITHER. WITH THIS IN MIND AND NO FORCING ARRIVING TO INTENSIFY THE LIFT OR ADVECT IN MUCH BETTER MOISTURE HAVE DECIDED TO GO DRIER THAN GUIDANCE AND HRRR AND MAINTAIN JUST A SLIGHT CHANCE IN THE SOUTHWESTERN COUNTIES WHERE DEW POINTS AT LEAST ARE IN THE 30S AND LOW 40S. WITH THE DRY AIR IT WILL JUST BE VERY DIFFICULT FOR ANY SORT OF MEASURABLE PRECIPITATION TO TAKE PLACE. WENT DRY AFTER 6Z. FOR TEMPERATURES STUCK CLOSE TO WARMER MAV NUMBERS AS THESE HAVE BEEN VERIFYING BETTER LATELY AND THAT PRODUCED LOWS IN THE 40S. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... ISSUED AT 340 PM EDT TUE APR 24 2012 FORECAST FOCUS IS ON POPS/THUNDER POTENTIAL. MODELS ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS APPROACH FOR THE MOST PART. WEDNESDAY SHOULD START OUT DRY WITH INCREASING CLOUDS AS A WARM FRONT FIRMS UP A BIT MORE SOUTH OF THE AREA AND AN UPPER WAVE APPROACHES FROM THE NORTHWEST. BY AFTERNOON THESE AFOREMENTIONED FEATURES SHOULD BRING CHANCES FOR THUNDERSTORMS TO THE AREA. OVERNIGHT THE SURFACE LOW WILL DRAG A COLD FRONT THROUGH THE AREA AND AN UPPER WAVE WILL MOVE THROUGH AS WELL...AND THIS SHOULD BRING THE BEST CHANCES FOR PRECIPITATION IN THE SHORT TERM. THUS WENT ALONG WITH LIKELIES IN THE MAV. DID CUT THE NORTH FROM THEIR LOW END CATEGORICAL OF THE MAV AS COVERAGE MAY NOT BE QUITE THAT GREAT BUT THOUGHT HIGH END LIKELIES CAPTURED THE THREAT WELL. ENTIRE FORECAST AREA IS IN A DAY 2 SLIGHT RISK BASED ON STEEP MID LEVEL LAPSE RATES BEING ABLE TO AID IN HAIL PRODUCTION...BUT WITH MODELS OVERDOING MOISTURE RETURN AND THUS INSTABILITY THINK WIDESPREAD SEVERE POTENTIAL IS LOW AND MORE INCLINED TO BELIEVE MOST STORMS WILL PRODUCE LOW END HAIL AND ONLY ISOLATED STORMS WILL PRODUCE EVEN QUARTER SIZE HAIL. FOR THURSDAY THERE IS SOME DISAGREEMENT ON HOW FAR SOUTH THE FRONT WILL GET. THUS THURSDAY MORNING MAINTAINED A CHANCE ACROSS SOUTHERN HALF OR SO OF THE AREA TAPERING TO DRY IN THE NORTH. BY AFTERNOON THE FRONT SHOULD BE FAR ENOUGH AWAY THAT DROPPED TO JUST A SLIGHT CHANCE ON THE SOUTHERN BORDER. MODELS ARE FASTER WITH PROGRESSING ANOTHER FRONT FROM THE PLAINS HOWEVER AND BRINGING SOME ISENTROPIC LIFT OVERNIGHT THURSDAY SO EXPANDED POPS A BIT MORE TO ALL BUT THE NORTHEASTERN COUNTIES. ON FRIDAY THIS FRONT SHOULD BE MOVING NORTH INTO THE AREA AND WENT WITH CHANCE ACROSS THE ENTIRE AREA. DEPENDING ON IF THIS FRONT STALLS AND STAYS FAIRLY STATIONARY INTO THE WEEKEND AS SOME MODELS ARE PREDICTING...COULD SEE SOME DECENT RAINFALL AMOUNTS. FOR TEMPERATURES GENERALLY WENT CLOSER TO WARMER GUIDANCE NUMBERS AS THIS HAS BEEN VERIFYING BETTER LATELY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... ISSUED AT 340 PM EDT TUE APR 24 2012 THERE IS A BETTER CONSENSUS AMONG THE MODELS ON WHEN THE PRECIPITATION WILL OCCUR DURING THE EXTENDED PERIOD. REALLY THE BEST CHANCES WILL RUN FROM FRIDAY THROUGH SATURDAY...WITH SOME LOWER CHANCES SATURDAY NIGHT AND ONLY A SLIGHT CHANCE BY SUNDAY. FELT CONFIDENT ENOUGH IN LONG TERM ENSEMBLES TO BUMPED POPS UP TO LIKELY FRIDAY NIGHT THROUGH SATURDAY...THOUGH CHANCES FOR CONVECTION LOOK LOW/WEAK AND KEPT THUNDER MENTION AT CHANCE TO ISOLATED. THE BULK OF THE INSTABILITY LIES FARTHER SOUTH OF THE FORECAST AREA...CLOSER TO THE FRONTAL BOUNDARY. LOOKS DRY FOR EARLY NEXT WORK WEEK AS RIDGE BUILDS BACK OVER THE REGION. && .AVIATION /DISCUSSION FOR THE 242100Z TAF UPDATES/... ISSUED AT 430 PM EDT TUE APR 24 2012 HAD TO DECREASE WINDS BASED ON OBSERVATIONAL TRENDS...OTHERWISE NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... VFR CONDITIONS EXPECTED FOR THE NEXT 24 HRS... GENERALLY QUIET WEATHER CONTINUES FOR CENTRAL INDIANA AS A RIDGE OF HIGH PRESSURE SLOWLY SLIDES EAST OVER THE REGION. A FEW MID LEVEL CLOUDS AND POSSIBLY A FEW SPRINKLES (THOUGH THE LATTER HAVE NOT BEEN REPORTED YET) HAVE MOVED OVER THE WESTERN CWA. THIS CLOUD DECK WILL SLOWLY SHIFT EASTWARD AND ENVELOPE THE REST OF THE TAF SITES THIS AFTERNOON. THIS WILL NOT HAVE AN IMPACT ON THE FLIGHT CATEGORY AS VFR CONDITIONS WILL BE THE PREVAILING FLIGHT CATEGORY FOR ENTIRE TAF PERIOD. HOWEVER...AS EXPECTED WINDS BEGAN TO PICK UP AND GUST ONCE AGAIN AROUND 15-16Z THIS AFTERNOON...THOUGH NOT EVEN CLOSE TO AS STRONG AS YESTERDAY...THIS AFTERNOON ONLY AROUND 20-22KT. LOCATIONS SUCH AS KHUF AND KBMG ARE NOT EXPECTING TO GUST OFTEN SO THIS WAS LEFT OUT OF THEIR TAFS. CLOUDS WILL BE ON THE INCREASE TOMORROW AHEAD OF A FRONT AND VCSH WAS INTRODUCED BY THE END OF KIND TAF PERIOD. MORE WIDESPREAD RAIN SHOWERS ARE ANTICIPATED BY WED NIGHT WITH A CHANCE FOR THUNDERSTORMS...SO THIS WILL LIKELY BE ADDED IN FORTHCOMING AVIATION FORECAST ISSUANCES. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....SMF AVIATION...SMF/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
342 PM EDT TUE APR 24 2012 .UPDATE... THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 340 PM EDT TUE APR 24 2012 A WARM FRONT TAKING SHAPE OVER THE PLAINS AND AN UPPER WAVE MOVING IN FROM THE NORTHERN PLAINS SHOULD BRING CHANCES FOR THUNDERSTORMS TO THE AREA WEDNESDAY AFTERNOON AND INTO THURSDAY. BY THURSDAY NIGHT ANOTHER FRONTAL SYSTEM WILL BRING MORE CHANCES TO THE AREA FOR MUCH OF THE WEEKEND BY STALLING THE FRONT AND HAVING SEVERAL WAVES MOVE ALONG IT. BY SUNDAY NIGHT UPPER RIDGING FINALLY STARTS MOVING IN TO DRY THINGS OUT UNTIL TUESDAY. && .NEAR TERM /TONIGHT/... ISSUED AT 340 PM EDT TUE APR 24 2012 RADAR ECHOES ACROSS WESTERN INDIANA AT 19Z ARE NOT PRODUCING ANYTHING BUT VIRGA AT THIS POINT. THOSE OVER ILLINOIS ARE OCCASIONALLY BEING OBSERVED BY ASOS BUT STILL HAVE NOT SEEN ANYTHING MEASURABLE THERE EITHER. WITH THIS IN MIND AND NO FORCING ARRIVING TO INTENSIFY THE LIFT OR ADVECT IN MUCH BETTER MOISTURE HAVE DECIDED TO GO DRIER THAN GUIDANCE AND HRRR AND MAINTAIN JUST A SLIGHT CHANCE IN THE SOUTHWESTERN COUNTIES WHERE DEW POINTS AT LEAST ARE IN THE 30S AND LOW 40S. WITH THE DRY AIR IT WILL JUST BE VERY DIFFICULT FOR ANY SORT OF MEASURABLE PRECIPITATION TO TAKE PLACE. WENT DRY AFTER 6Z. FOR TEMPERATURES STUCK CLOSE TO WARMER MAV NUMBERS AS THESE HAVE BEEN VERIFYING BETTER LATELY AND THAT PRODUCED LOWS IN THE 40S. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... ISSUED AT 340 PM EDT TUE APR 24 2012 FORECAST FOCUS IS ON POPS/THUNDER POTENTIAL. MODELS ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS APPROACH FOR THE MOST PART. WEDNESDAY SHOULD START OUT DRY WITH INCREASING CLOUDS AS A WARM FRONT FIRMS UP A BIT MORE SOUTH OF THE AREA AND AN UPPER WAVE APPROACHES FROM THE NORTHWEST. BY AFTERNOON THESE AFOREMENTIONED FEATURES SHOULD BRING CHANCES FOR THUNDERSTORMS TO THE AREA. OVERNIGHT THE SURFACE LOW WILL DRAG A COLD FRONT THROUGH THE AREA AND AN UPPER WAVE WILL MOVE THROUGH AS WELL...AND THIS SHOULD BRING THE BEST CHANCES FOR PRECIPITATION IN THE SHORT TERM. THUS WENT ALONG WITH LIKELIES IN THE MAV. DID CUT THE NORTH FROM THEIR LOW END CATEGORICAL OF THE MAV AS COVERAGE MAY NOT BE QUITE THAT GREAT BUT THOUGHT HIGH END LIKELIES CAPTURED THE THREAT WELL. ENTIRE FORECAST AREA IS IN A DAY 2 SLIGHT RISK BASED ON STEEP MID LEVEL LAPSE RATES BEING ABLE TO AID IN HAIL PRODUCTION...BUT WITH MODELS OVERDOING MOISTURE RETURN AND THUS INSTABILITY THINK WIDESPREAD SEVERE POTENTIAL IS LOW AND MORE INCLINED TO BELIEVE MOST STORMS WILL PRODUCE LOW END HAIL AND ONLY ISOLATED STORMS WILL PRODUCE EVEN QUARTER SIZE HAIL. FOR THURSDAY THERE IS SOME DISAGREEMENT ON HOW FAR SOUTH THE FRONT WILL GET. THUS THURSDAY MORNING MAINTAINED A CHANCE ACROSS SOUTHERN HALF OR SO OF THE AREA TAPERING TO DRY IN THE NORTH. BY AFTERNOON THE FRONT SHOULD BE FAR ENOUGH AWAY THAT DROPPED TO JUST A SLIGHT CHANCE ON THE SOUTHERN BORDER. MODELS ARE FASTER WITH PROGRESSING ANOTHER FRONT FROM THE PLAINS HOWEVER AND BRINGING SOME ISENTROPIC LIFT OVERNIGHT THURSDAY SO EXPANDED POPS A BIT MORE TO ALL BUT THE NORTHEASTERN COUNTIES. ON FRIDAY THIS FRONT SHOULD BE MOVING NORTH INTO THE AREA AND WENT WITH CHANCE ACROSS THE ENTIRE AREA. DEPENDING ON IF THIS FRONT STALLS AND STAYS FAIRLY STATIONARY INTO THE WEEKEND AS SOME MODELS ARE PREDICTING...COULD SEE SOME DECENT RAINFALL AMOUNTS. FOR TEMPERATURES GENERALLY WENT CLOSER TO WARMER GUIDANCE NUMBERS AS THIS HAS BEEN VERIFYING BETTER LATELY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... ISSUED AT 340 PM EDT TUE APR 24 2012 THERE IS A BETTER CONSENSUS AMONG THE MODELS ON WHEN THE PRECIPITATION WILL OCCUR DURING THE EXTENDED PERIOD. REALLY THE BEST CHANCES WILL RUN FROM FRIDAY THROUGH SATURDAY...WITH SOME LOWER CHANCES SATURDAY NIGHT AND ONLY A SLIGHT CHANCE BY SUNDAY. FELT CONFIDENT ENOUGH IN LONG TERM ENSEMBLES TO BUMPED POPS UP TO LIKELY FRIDAY NIGHT THROUGH SATURDAY...THOUGH CHANCES FOR CONVECTION LOOK LOW/WEAK AND KEPT THUNDER MENTION AT CHANCE TO ISOLATED. THE BULK OF THE INSTABILITY LIES FARTHER SOUTH OF THE FORECAST AREA...CLOSER TO THE FRONTAL BOUNDARY. LOOKS DRY FOR EARLY NEXT WORK WEEK AS RIDGE BUILDS BACK OVER THE REGION. && .AVIATION /DISCUSSION FOR THE 241800Z TAF ISSUANCE/... ISSUED AT 1256 PM EDT TUE APR 24 2012 VFR CONDITIONS EXPECTED FOR THE NEXT 24 HRS... GENERALLY QUIET WEATHER CONTINUES FOR CENTRAL INDIANA AS A RIDGE OF HIGH PRESSURE SLOWLY SLIDES EAST OVER THE REGION. A FEW MID LEVEL CLOUDS AND POSSIBLY A FEW SPRINKLES (THOUGH THE LATTER HAVE NOT BEEN REPORTED YET) HAVE MOVED OVER THE WESTERN CWA. THIS CLOUD DECK WILL SLOWLY SHIFT EASTWARD AND ENVELOPE THE REST OF THE TAF SITES THIS AFTERNOON. THIS WILL NOT HAVE AN IMPACT ON THE FLIGHT CATEGORY AS VFR CONDITIONS WILL BE THE PREVAILING FLIGHT CATEGORY FOR ENTIRE TAF PERIOD. HOWEVER...AS EXPECTED WINDS BEGAN TO PICK UP AND GUST ONCE AGAIN AROUND 15-16Z THIS AFTERNOON...THOUGH NOT EVEN CLOSE TO AS STRONG AS YESTERDAY...THIS AFTERNOON ONLY AROUND 20-22KT. LOCATIONS SUCH AS KHUF AND KBMG ARE NOT EXPECTING TO GUST OFTEN SO THIS WAS LEFT OUT OF THEIR TAFS. CLOUDS WILL BE ON THE INCREASE TOMORROW AHEAD OF A FRONT AND VCSH WAS INTRODUCED BY THE END OF KIND TAF PERIOD. MORE WIDESPREAD RAIN SHOWERS ARE ANTICIPATED BY WED NIGHT WITH A CHANCE FOR THUNDERSTORMS...SO THIS WILL LIKELY BE ADDED IN FORTHCOMING AVIATION FORECAST ISSUANCES. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....SMF AVIATION...SMF
AREA FORECAST DISCUSSION
NWS JACKSON KY
1022 PM EDT WED APR 25 2012 .UPDATE... ISSUED AT 1015 PM EDT WED APR 25 2012 SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO CROSS ERN KY THIS EVENING. STRONGEST STORMS PRODUCING SOME LIGHTNING AND RADAR ESTIMATED TENTH OF AN INCH OF RAINFALL PER HOUR. STORMS ARE MOVING EAST...100 DEG...AT NEARLY 40 PH SO NO STORM IS PRODUCING HEAVY RAIN RFOR ANY GIVEN LOCATION. PARENT LOW IS STILL LOCATED OVER WRN IL WITH A WARM FRONT EXTENDING THRU ERN KY JUST NORTH OF LEX AND JUST SOUTH OF JKL/PIKEVILLE. LOW PRESSURE SHOULD CONTINUE TO TRACK EAST WITH THE WARM FRONT LIFTING TOWARD CVG AND PULLING MUCH OF THE PCPN NORTH OF THE AREA. EXPECTING SRN KY TO SEE LITTLE ADDITIONAL PCPN WHILE NRN KY WILL SEE ADDITIONAL ROUNDS OF SHRA THRU MUCH OF THE NIGHT. SPEED OF THE STORMS WILL LIMIT TOTAL ACCUMULATION. GRIDS HAVE BEEN UPDATED WITH EXPECTED POPS AND TEMPS. ZONES IN GOOD SHAPE WITH NO UPDATE REQUIRED. UPDATE ISSUED AT 757 PM EDT WED APR 25 2012 UPDATED FOR SHRA CROSSING ERN KY. ACTIVITY SHOULD BECOME RATHE PERSISTENT FOR OUR NRN COUNTIES AND SHOULD SEE BREAKS IN THE ACTIVITY FOR THE SWRN THIRD. TEMPS ON TRACK BUT HAVE TWEAKED SLIGHTLY TO ACCOUNT FOR THE EARLIER ONSET OF PCPN. NOT SEEING ANY LIGHTNING AND HAVE DOWNGRADED THE THUNDER CHANCES. MAY NEED TO TAKE THEM OUT COMPLETELY LATER TONIGHT. WILL CONTINUE TO MONITOR. UPDATE ISSUED AT 449 PM EDT WED APR 25 2012 TIMING OF CONVECTION APPROACHING FROM THE WEST AND FURTHER CONVECTION ANTICIPATED LATER THIS EVENING AS WELL AS ASSOCIATED SKY COVER WAS ADJUSTED BASED ON THE LATEST SAT AND RADAR TRENDS. OVERALL...THE 18Z NAM HAS A DECENT HANDLE ON THE APPROACHING CONVECTION...BUT APPEARS TO BE A BIT TOO SLOW. CONVECTION OVER THE NEXT 2 HOURS OR SO SHOULD GENERALLY BE OVER THE SW CWA AND THEN PROBABLY BECOME FOCUS MORE TO THE NE CLOSER TO THE WARM FRONT AND GREATER THETA AND DEWPOINT GRADIENTS AS THE EVENING WEARS ON. CONVECTION THIS EVENING OR EARLY TONIGHT IS STILL CAPABLE OF PRODUCING SOME HAIL OR STRONG WIND GUSTS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 325 PM EDT WED APR 25 2012 A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM. AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL KY. OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD THE CWA FROM LATE ON THU INTO THU NIGHT. THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA. SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA. ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA. IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON. AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 325 PM EDT WED APR 25 2012 MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE WEEKEND AND BEYOND. THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY. HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY. A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH THIS BOUNDARY AROUND OUR REGION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 740 PM EDT WED APR 25 2012 SCATTERED SHRA MOVING FROM NW TO SE ACROSS ERN KY. THE GREATEST PROBABILITY FOR CONVECTION STILL APPEARS TO BE FROM ABOUT 03Z- 10Z...ESPECIALLY ALONG AND NORTH OF A KLEX TO KHAZ TO KLNP LINE. THESE COULD BRIEFLY BRING CONDITIONS AS LOW AS MVFR ALONG WITH GUSTY WINDS AND PERHAPS SOME HAIL OR AT LEAST HAIL ALOFT. ENOUGH SATURATION SHOULD OCCUR NEARER TO THE COLD FRONT THAT WILL DROP INTO THE AREA TONIGHT THAT AFTER THE 10Z TIME FRAME...SOME PREVAILING MVFR SHOULD DEVELOP AND PERSIST FOR MOST OF THE OVERNIGHT PERIOD WITH CONDITIONS RETURNING TO VFR FOR THE AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DUSTY SHORT TERM...JP LONG TERM....KAS AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS JACKSON KY
801 PM EDT WED APR 25 2012 .UPDATE... ISSUED AT 757 PM EDT WED APR 25 2012 UPDATED FOR SHRA CROSSING ERN KY. ACTIVITY SHOULD BECOME RATHE PERSISTENT FOR OUR NRN COUNTIES AND SHOULD SEE BREAKS IN THE ACTIVITY FOR THE SWRN THIRD. TEMPS ON TRACK BUT HAVE TWEAKED SLIGHTLY TO ACCOUNT FOR THE EARLIER ONSET OF PCPN. NOT SEEING ANY LIGHTNING AND HAVE DOWNGRADED THE THUNDER CHANCES. MAY NEED TO TAKE THEM OUT COMPLETELY LATER TONIGHT. WILL CONTINUE TO MONITOR. UPDATE ISSUED AT 449 PM EDT WED APR 25 2012 TIMING OF CONVECTION APPROACHING FROM THE WEST AND FURTHER CONVECTION ANTICIPATED LATER THIS EVENING AS WELL AS ASSOCIATED SKY COVER WAS ADJUSTED BASED ON THE LATEST SAT AND RADAR TRENDS. OVERALL...THE 18Z NAM HAS A DECENT HANDLE ON THE APPROACHING CONVECTION...BUT APPEARS TO BE A BIT TOO SLOW. CONVECTION OVER THE NEXT 2 HOURS OR SO SHOULD GENERALLY BE OVER THE SW CWA AND THEN PROBABLY BECOME FOCUS MORE TO THE NE CLOSER TO THE WARM FRONT AND GREATER THETA AND DEWPOINT GRADIENTS AS THE EVENING WEARS ON. CONVECTION THIS EVENING OR EARLY TONIGHT IS STILL CAPABLE OF PRODUCING SOME HAIL OR STRONG WIND GUSTS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 325 PM EDT WED APR 25 2012 A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM. AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL KY. OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD THE CWA FROM LATE ON THU INTO THU NIGHT. THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA. SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA. ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA. IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON. AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 325 PM EDT WED APR 25 2012 MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE WEEKEND AND BEYOND. THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY. HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY. A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH THIS BOUNDARY AROUND OUR REGION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 740 PM EDT WED APR 25 2012 SCATTERED SHRA MOVING FROM NW TO SE ACROSS ERN KY. THE GREATEST PROBABILITY FOR CONVECTION STILL APPEARS TO BE FROM ABOUT 03Z- 10Z...ESPECIALLY ALONG AND NORTH OF A KLEX TO KHAZ TO KLNP LINE. THESE COULD BRIEFLY BRING CONDITIONS AS LOW AS MVFR ALONG WITH GUSTY WINDS AND PERHAPS SOME HAIL OR AT LEAST HAIL ALOFT. ENOUGH SATURATION SHOULD OCCUR NEARER TO THE COLD FRONT THAT WILL DROP INTO THE AREA TONIGHT THAT AFTER THE 10Z TIME FRAME...SOME PREVAILING MVFR SHOULD DEVELOP AND PERSIST FOR MOST OF THE OVERNIGHT PERIOD WITH CONDITIONS RETURNING TO VFR FOR THE AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DUSTY SHORT TERM...JP LONG TERM....KAS AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS JACKSON KY
742 PM EDT WED APR 25 2012 .UPDATE... ISSUED AT 449 PM EDT WED APR 25 2012 TIMING OF CONVECTION APPROACHING FROM THE WEST AND FURTHER CONVECTION ANTICIPATED LATER THIS EVENING AS WELL AS ASSOCIATED SKY COVER WAS ADJUSTED BASED ON THE LATEST SAT AND RADAR TRENDS. OVERALL...THE 18Z NAM HAS A DECENT HANDLE ON THE APPROACHING CONVECTION...BUT APPEARS TO BE A BIT TOO SLOW. CONVECTION OVER THE NEXT 2 HOURS OR SO SHOULD GENERALLY BE OVER THE SW CWA AND THEN PROBABLY BECOME FOCUS MORE TO THE NE CLOSER TO THE WARM FRONT AND GREATER THETA AND DEWPOINT GRADIENTS AS THE EVENING WEARS ON. CONVECTION THIS EVENING OR EARLY TONIGHT IS STILL CAPABLE OF PRODUCING SOME HAIL OR STRONG WIND GUSTS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 325 PM EDT WED APR 25 2012 A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM. AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL KY. OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD THE CWA FROM LATE ON THU INTO THU NIGHT. THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA. SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA. ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA. IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON. AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 325 PM EDT WED APR 25 2012 MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE WEEKEND AND BEYOND. THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY. HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY. A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH THIS BOUNDARY AROUND OUR REGION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 740 PM EDT WED APR 25 2012 SCATTERED SHRA MOVING FROM NW TO SE ACROSS ERN KY. THE GREATEST PROBABILITY FOR CONVECTION STILL APPEARS TO BE FROM ABOUT 03Z- 10Z...ESPECIALLY ALONG AND NORTH OF A KLEX TO KHAZ TO KLNP LINE. THESE COULD BRIEFLY BRING CONDITIONS AS LOW AS MVFR ALONG WITH GUSTY WINDS AND PERHAPS SOME HAIL OR AT LEAST HAIL ALOFT. ENOUGH SATURATION SHOULD OCCUR NEARER TO THE COLD FRONT THAT WILL DROP INTO THE AREA TONIGHT THAT AFTER THE 10Z TIME FRAME...SOME PREVAILING MVFR SHOULD DEVELOP AND PERSIST FOR MOST OF THE OVERNIGHT PERIOD WITH CONDITIONS RETURNING TO VFR FOR THE AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...JP LONG TERM....KAS AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1021 PM EDT WED APR 25 2012 .SYNOPSIS... ISSUED AT 353 PM EDT WED APR 25 2012 RAIN IS EXPECTED OVERNIGHT WITH ISOLATED THUNDERSTORMS POSSIBLE SOUTH OF INTERSTATE 96. AFTER A DRY FRIDAY...A CHANCE FOR RAIN WILL RETURN SATURDAY...AGAIN MAINLY SOUTH OF I-96. THE WEEKEND WILL BE SEASONABLY COOL. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN BY THE MIDDLE OF NEXT WORK WEEK WITH TEMPERATURES GRADUALLY RISING TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES. && .UPDATE... ISSUED AT 1021 PM EDT WED APR 25 2012 MADE A COUPLE OF TWEAKS TO THE GRIDS. REGIONAL RADAR SHOWS SHOWERS MOVING SOUTHEAST ACROSS THE CWA AS LOW PRESSURE OVER ILLINOIS MOVES BY TO THE SOUTH. I THINK THE THUNDER THREAT IS OVER AND HAVE REMOVED THUNDER FROM THE GRIDS. ALSO ADJUSTED THE TIMING OF THE FREEZE WARNING. WE/LL LIKELY NOT SEE FROST OR FREEZING TEMPS UNTIL AFTER 06Z FRIDAY AND HAVE ADJUSTED THE GRIDS ACCORDINGLY. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 353 PM EDT WED APR 25 2012 MAIN CONCERN IS PRECIPITATION OVERNIGHT. THE ONLY CHANGES TO THE PREVIOUS FORECAST WERE TO DELAY THE ONSET OF PRECIPITATION SLIGHTLY AND TO INCREASE POPS DUE TO EXPECTED WIDESPREAD COVERAGE OF RAIN. SPC OUTLOOKS AND CALIBRATED SREF GUIDANCE CONTINUE TO ADVERTISE THUNDER POTENTIAL GENERALLY SOUTH OF I-96 FROM THIS EVENING THROUGH EARLY THURSDAY MORNING. OTHER CONCERN IS FREEZING TEMPERATURES FRIDAY MORNING. HAVE ISSUED A FREEZE WATCH FOR THE ENTIRE FORECAST AREA...AND THERE IS A VERY GOOD CHANCE THIS WILL NEED TO BECOME A WARNING AS GUIDANCE TEMPERATURES CURRENTLY SUGGEST SEVERAL HOURS OF SUB-30 TEMPERATURES OVER NEARLY ALL OF THE WATCH AREA. THANKS TO IWX FOR COORDINATION. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 408 PM EDT WED APR 25 2012 LONG TERM BEGINS WITH RIDGING IN PLACE BOTH AT THE SURFACE AND ALOFT. A SHORTWAVE TRIES TO SLIDE IN FROM THE WEST FRIDAY NIGHT AND HAVE CHANCES POPS IN THE SOUTH AT THIS POINT. THE WAVE IS BEING ABSORBED BY THE RIDGE A BIT...ESPECIALLY IN THE EUROPEAN. THE GFS HANGS ON TO THE SHORTWAVE A BIT MORE AND HAS MORE RAIN. DIFFERENCES RANGE FROM A QUARTER INCH IN THE SOUTHWEST FRIDAY NIGHT TO LESS THAN A TENTH OF AN INCH IN THE EURO. THE LOW SLIDES EAST ON SATURDAY WITH CONTINUED RAIN CHANCES IN THE SOUTH VIA BOTH MODELS. THE GFS WOULD EVEN SUGGEST SOME SNOW IS POSSIBLE...BUT HAVE KEPT THINGS ALL RAIN AT THIS POINT. RIDGING GRADUALLY SETTLES INTO THE GREAT LAKES SATURDAY NIGHT INTO SUNDAY AND KEEPS CONDITIONS DRY AND COOL INTO MONDAY NIGHT. HEIGHTS RISE INTO MID NEXT WEEK...WITH A WARMING TREND. LOW PRESSURE WILL MOVE INTO THE NORTHERN PLAINS STATES MID WEEK WHICH WILL BRING A SOUTHERLY FLOW AND CHANCES FOR SHOWERS TUESDAY AND WEDNESDAY. THUNDERSTORM CHANCES EXIST ON WEDNESDAY AS INSTABILITY DEVELOPS. BOTTOM LINE IS...RAIN CHANCES FRIDAY NIGHT INTO SATURDAY ESPECIALLY IN THE SOUTH. SNOW NOT OUT OF THE REALM OF POSSIBILITIES SATURDAY MORNING. DRY AND COOL FROM THE WEEKEND INTO EARLY NEXT WEEK...FOLLOWED BY A SOLID WARM UP TUESDAY/WEDNESDAY. 70S NOT OUT OF THE QUESTION ON WEDNESDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 748 PM EDT WED APR 25 2012 FOR THE MOST PART THIS EVENING VFR CIGS/VSBY SHOULD PREVAIL EVEN THROUGH RAIN SHOWERS WILL OCCUR FROM TIME TO TIME. EXPECT GUSTY WINDS WITH THOSE SHOWERS UNTIL AROUND 03Z. THE RUC MODEL SOUNDINGS SHOWS 30 TO 35 KNOTS BETWEEN 1000 FT AGL AND 2000 FT AGL WITH AN INVERTED "V" LOOK TO THEM. THAT WILL ALLOW SOME OF THOSE STRONG WINDS TO BE BROUGHT DOWN THE SURFACE. BY 03Z- 04Z THE LOW LEVELS SHOULD MOISTEN ENOUGH FOR THAT TO NO LONGER BE AN ISSUE. THERE IS ELEVATED INSTABILITY INTO THE EARLY MORNING HOURS... MOSTLY NEAR AND SOUTH OF I-94. EVEN THROUGH MOST OF THE THUNDERSTORMS SHOULD STAY WELL SOUTH OF THE GRR CWA TONIGHT... IT WOULD NOT BE OUT OF THE QUESTION FOR AN ISOLATED THUNDERSTORMS. I KEPT THE VCTS IN THE I-94 TAFS TO COVER THAT ISSUE. AFTER THE SHOWERS ARE DONE... AFTER 06Z OR SO... THE LOW LEVELS MOISTEN UP SO EXPECT CIGS TO BECOME IFR UNTIL THE COLD FRONT COMES THROUGH AROUND 12Z OR SO. RAPID CLEARING WILL FOLLOW THE COLD FRONT. && .MARINE... ISSUED AT 353 PM EDT WED APR 25 2012 AFTER COORDINATION WITH LOT AND IWX...HAVE ISSUED A SCA BEGINNING THURSDAY MORNING WHEN WINDS AND WAVES SHOULD RAMP UP QUICKLY. BORDERLINE GALES WILL BE POSSIBLE FARTHER NORTH NEAR THE SABLE POINTS WHERE THE WATERS WILL HAVE A BETTER EXPOSURE TO EXPECTED NORTH WINDS. && .HYDROLOGY... ISSUED AT 353 PM EDT WED APR 25 2012 NO CONCERNS ARE ANTICIPATED. QPF TOTALS BY THURSDAY AFTERNOON RANGE BETWEEN 0.20 TO 0.60 INCHES GOING FROM NORTHEAST TO SOUTHWEST. RIVER BASE FLOWS ARE LOW ENOUGH TO ACCOMMODATE THIS WITH LITTLE OR NO IMPACT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR MIZ037>040-043>046-050>052-056>059-064>067-071>074. LM...SMALL CRAFT ADVISORY FROM 8 AM THURSDAY TO 11 AM EDT FRIDAY FOR LMZ844>849. && $$ UPDATE...93 SYNOPSIS...TJT SHORT TERM...TJT LONG TERM...DUKE AVIATION...WDM HYDROLOGY...TJT MARINE...TJT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
748 PM EDT WED APR 25 2012 .SYNOPSIS... ISSUED AT 353 PM EDT WED APR 25 2012 RAIN IS EXPECTED OVERNIGHT WITH ISOLATED THUNDERSTORMS POSSIBLE SOUTH OF INTERSTATE 96. AFTER A DRY FRIDAY...A CHANCE FOR RAIN WILL RETURN SATURDAY...AGAIN MAINLY SOUTH OF I-96. THE WEEKEND WILL BE SEASONABLY COOL. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN BY THE MIDDLE OF NEXT WORK WEEK WITH TEMPERATURES GRADUALLY RISING TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 353 PM EDT WED APR 25 2012 MAIN CONCERN IS PRECIPITATION OVERNIGHT. THE ONLY CHANGES TO THE PREVIOUS FORECAST WERE TO DELAY THE ONSET OF PRECIPITATION SLIGHTLY AND TO INCREASE POPS DUE TO EXPECTED WIDESPREAD COVERAGE OF RAIN. SPC OUTLOOKS AND CALIBRATED SREF GUIDANCE CONTINUE TO ADVERTISE THUNDER POTENTIAL GENERALLY SOUTH OF I-96 FROM THIS EVENING THROUGH EARLY THURSDAY MORNING. OTHER CONCERN IS FREEZING TEMPERATURES FRIDAY MORNING. HAVE ISSUED A FREEZE WATCH FOR THE ENTIRE FORECAST AREA...AND THERE IS A VERY GOOD CHANCE THIS WILL NEED TO BECOME A WARNING AS GUIDANCE TEMPERATURES CURRENTLY SUGGEST SEVERAL HOURS OF SUB-30 TEMPERATURES OVER NEARLY ALL OF THE WATCH AREA. THANKS TO IWX FOR COORDINATION. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 408 PM EDT WED APR 25 2012 LONG TERM BEGINS WITH RIDGING IN PLACE BOTH AT THE SURFACE AND ALOFT. A SHORTWAVE TRIES TO SLIDE IN FROM THE WEST FRIDAY NIGHT AND HAVE CHANCES POPS IN THE SOUTH AT THIS POINT. THE WAVE IS BEING ABSORBED BY THE RIDGE A BIT...ESPECIALLY IN THE EUROPEAN. THE GFS HANGS ON TO THE SHORTWAVE A BIT MORE AND HAS MORE RAIN. DIFFERENCES RANGE FROM A QUARTER INCH IN THE SOUTHWEST FRIDAY NIGHT TO LESS THAN A TENTH OF AN INCH IN THE EURO. THE LOW SLIDES EAST ON SATURDAY WITH CONTINUED RAIN CHANCES IN THE SOUTH VIA BOTH MODELS. THE GFS WOULD EVEN SUGGEST SOME SNOW IS POSSIBLE...BUT HAVE KEPT THINGS ALL RAIN AT THIS POINT. RIDGING GRADUALLY SETTLES INTO THE GREAT LAKES SATURDAY NIGHT INTO SUNDAY AND KEEPS CONDITIONS DRY AND COOL INTO MONDAY NIGHT. HEIGHTS RISE INTO MID NEXT WEEK...WITH A WARMING TREND. LOW PRESSURE WILL MOVE INTO THE NORTHERN PLAINS STATES MID WEEK WHICH WILL BRING A SOUTHERLY FLOW AND CHANCES FOR SHOWERS TUESDAY AND WEDNESDAY. THUNDERSTORM CHANCES EXIST ON WEDNESDAY AS INSTABILITY DEVELOPS. BOTTOM LINE IS...RAIN CHANCES FRIDAY NIGHT INTO SATURDAY ESPECIALLY IN THE SOUTH. SNOW NOT OUT OF THE REALM OF POSSIBILITIES SATURDAY MORNING. DRY AND COOL FROM THE WEEKEND INTO EARLY NEXT WEEK...FOLLOWED BY A SOLID WARM UP TUESDAY/WEDNESDAY. 70S NOT OUT OF THE QUESTION ON WEDNESDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 748 PM EDT WED APR 25 2012 FOR THE MOST PART THIS EVENING VFR CIGS/VSBY SHOULD PREVAIL EVEN THROUGH RAIN SHOWERS WILL OCCUR FROM TIME TO TIME. EXPECT GUSTY WINDS WITH THOSE SHOWERS UNTIL AROUND 03Z. THE RUC MODEL SOUNDINGS SHOWS 30 TO 35 KNOTS BETWEEN 1000 FT AGL AND 2000 FT AGL WITH AN INVERTED "V" LOOK TO THEM. THAT WILL ALLOW SOME OF THOSE STRONG WINDS TO BE BROUGHT DOWN THE SURFACE. BY 03Z- 04Z THE LOW LEVELS SHOULD MOISTEN ENOUGH FOR THAT TO NO LONGER BE AN ISSUE. THERE IS ELEVATED INSTABILITY INTO THE EARLY MORNING HOURS... MOSTLY NEAR AND SOUTH OF I-94. EVEN THROUGH MOST OF THE THUNDERSTORMS SHOULD STAY WELL SOUTH OF THE GRR CWA TONIGHT... IT WOULD NOT BE OUT OF THE QUESTION FOR AN ISOLATED THUNDERSTORMS. I KEPT THE VCTS IN THE I-94 TAFS TO COVER THAT ISSUE. AFTER THE SHOWERS ARE DONE... AFTER 06Z OR SO... THE LOW LEVELS MOISTEN UP SO EXPECT CIGS TO BECOME IFR UNTIL THE COLD FRONT COMES THROUGH AROUND 12Z OR SO. RAPID CLEARING WILL FOLLOW THE COLD FRONT. && .MARINE... ISSUED AT 353 PM EDT WED APR 25 2012 AFTER COORDINATION WITH LOT AND IWX...HAVE ISSUED A SCA BEGINNING THURSDAY MORNING WHEN WINDS AND WAVES SHOULD RAMP UP QUICKLY. BORDERLINE GALES WILL BE POSSIBLE FARTHER NORTH NEAR THE SABLE POINTS WHERE THE WATERS WILL HAVE A BETTER EXPOSURE TO EXPECTED NORTH WINDS. && .HYDROLOGY... ISSUED AT 353 PM EDT WED APR 25 2012 NO CONCERNS ARE ANTICIPATED. QPF TOTALS BY THURSDAY AFTERNOON RANGE BETWEEN 0.20 TO 0.60 INCHES GOING FROM NORTHEAST TO SOUTHWEST. RIVER BASE FLOWS ARE LOW ENOUGH TO ACCOMMODATE THIS WITH LITTLE OR NO IMPACT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...FREEZE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR MIZ037>040-043>046-050>052-056>059-064>067-071>074. LM...SMALL CRAFT ADVISORY FROM 8 AM THURSDAY TO 11 AM EDT FRIDAY FOR LMZ844>849. && $$ SYNOPSIS...TJT SHORT TERM...TJT LONG TERM...DUKE AVIATION...WDM HYDROLOGY...TJT MARINE...TJT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
741 PM EDT WED APR 25 2012 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 414 PM EDT WED APR 25 2012 SEVERAL EMBEDDED SHORTWAVES HAVE BEEN MOVING THROUGH THE NW FLOW ACROSS THE UPPER MISS VALLEY AND UPPER GREAT LKS TODAY. WHEN THESE WAVES HAVE INTERACTED WITH THE H925-700 WAA UNDER WEAK SW FLOW...AS SEEN ON RUC ANALYSIS...THEY HAVE PRODUCED AREAS OF LIGHT RAIN SHOWERS OVER NE MN...NW WI AND ALONG THE WI/MI BORDER. WITH THE LLVL DRY AIR IN PLACE OVER MUCH OF UPPER MI AND LITTLE ESE MOVEMENT OF THE SHOWERS...THEY HAVE STRUGGLED TO EFFECT THE AREA. ATTENTION THEN TURNS FARTHER UPSTREAM IN SW ONTARIO WHERE ANOTHER SHORTWAVE AND WEAK WAA HAS BEEN SLOWLY MOVING SE INTO WRN LK SUPERIOR. THIS AREA OF MOISTURE/WAA WILL MERGE WITH SHORTWAVE DROPPING S JUST E OF LK WINNIPEG AND MOVE ACROSS LAKE SUPERIOR TONIGHT. 06 AND 12Z MODEL RUNS REALLY TRENDED THAT DIRECTION AND EARLIER UPDATE TO THE FORECAST WENT WITH THIS IDEA. THINK THESE SHOWERS WILL SLIDE INTO THE WRN PART OF UPPER MI THIS EVENING AND TRY TO SPEED UP AS FRONTAL BOUNDARY ASSOCIATED WITH THE SHORTWAVE PUSHES IT TO THE SE. AS THIS SLIDES ESE ACROSS THE AREA...IT WILL BE INTERACTING WITH THE LINGERING DRY LLVL AIR. MODELS CONSISTENT ON THIS PCPN DIMINISHING SOME AS IT HITS THE DRIER AIR...SO HAVE THE LIKELY POPS OVER THE WRN HALF OF THE CWA AN DIMINISHED TO CHANCES AS IT MOVES INTO THE DRIER AIR. AFTER THE INITIAL PCPN SLIDES THROUGH...COULD HAVE A SECONDARY AREA ASSOCIATED WITH THE SFC-H850 FRONT MOVING THROUGH AFTER 6Z. FORCING ALONG THE FRONT...ALONG WITH THE STRONG SHORTWAVE...SHOULD LEAD TO ANOTHER BAND OF RAIN...POTENTIALLY MIXING WITH OR CHANGING TO SNOW AFFECTING THE NRN HALF OF THE CWA. SOME OF THESE SHOWERS WILL BE ENHANCED IN THE UPSLOPE N FLOW AREAS...WHICH IF IT CHANGES TO ALL SNOW...COULD PRODUCE A LIGHT DUSTING OF SNOW OVER THE WEST AND NCNTRL. EXPECT WINDS TO QUICKLY PICKUP ALONG THIS FRONT AND GUST TO 25-30KTS NEAR LK SUPERIOR LATE TONIGHT AND INTO THURS MORNING. CONSIDERED PUTTING UP A GALE FOR THE ERN HALF OF LK SUPERIOR...AS WINDS RIGHT ALONG THE FRONT WILL GUST TO 35 AND POTENTIALLY 40KTS...BUT SHOULD ONLY BE FOR A BRIEF 1-2HR WINDOW BEFORE DIMINISHING BACK BELOW 35KTS. AS THE FRONT QUICKLY MOVES THROUGH...H850 TEMPS AROUND -9C WILL PROVIDE ENOUGH DELTA-T FOR CLOUDS AS LONG AS MOISTURE REMAINS. SHOULD BE ENOUGH LLVL MOISTURE...AROUND H925-850...TO SUSTAIN CLOUDS NEAR LK SUPERIOR FOR THE FIRST PART OF THE MORNING OVER THE WEST AND INTO THE AFTN OVER THE EAST. DID LEAVE SOME LINGERING -SHSN FOR UPSLOPE LOCATIONS NEAR LK SUPERIOR OVER THE NCNTRL AND EAST...BUT SHOULD DIMINISH FAIRLY QUICKLY WITH THE DRY AIR AND SUBSIDENCE FROM HIGH PRESSURE RIDGE MOVING OVER WRN LK SUPERIOR. IT WILL FEEL MUCH COOLER THAN TODAY OVER MUCH OF THE AREA...BUT ESPECIALLY OVER THE N HALF...AS THE COLD AIR AND WINDS OFF LK SUPERIOR WILL MAKE IT FEEL MUCH COLDER THAT THE LOW-MID 40S HIGHS. IN ADDITION...WITH THE DRY AIR ALOFT AND MIXING WITH THE WINDS WILL LEAD TO FALLING DEWPOINTS FROM WEST TO EAST. RH FALLING TO 25-30 PERCENT OVER THE WEST...BUT FORTUNATELY THE WINDS WILL BE DIMINISHING AND COOLER TEMPS WILL LIMIT FIRE WX CONCERN. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 414 PM EDT WED APR 25 2012 DRY CONDITIONS MAIN THEME OF LONG TERM. VERY LIMITED OPPORTUNITIES FOR RAINFALL IS IN THE FCST THROUGH MONDAY AS HIGH PRESSURE REGINS OVR THE REGION. INITIALLY WINDS WILL BE OUT OF THE NORTH OR NORTHEAST AS THE HIGH CENTER SETTLES FM NORTHERN MANITOBA AND NINAVUT CANADA ACROSS MUCH OF THE EASTERN CONUS BY EARLY NEXT WEEK. HIGH IS FCST TO PUSH TOWARD EAST CONUS COAST BY TUESDAY ALLOWING SOUTH TO SOUTHWEST RETURN FLOW TO FORM FM THE PLAINS INTO THE WESTERN GREAT LAKES. MOISTURE RETURN INTO GREAT LAKES IS MINIMAL AND DESPITE APPROACH OF A SFC-H85 TROUGH BELIEVE CHANCES OF ANY PRECIPITATION ARE PRETTY SMALL. CONSENSUS OF AVAILABLE MODELS GIVES LOW CHANCE POPS TUESDAY THROUGH WEDNESDAY AS THE TROUGH WORKS THROUGH. LARGE TROUGH RESIDING OVER MUCH OF EASTERN CANADA AND NORTHEAST CONUS WILL KEEP TEMPS GENERALLY AT OR BLO NORMAL THROUGH MUCH OF THE PERIOD...ESPECIALLY NEAR LK SUPERIOR WITH PERSISTENT ONSHORE FLOW. NEAR NORMAL OR POSSIBLY SLIGHTLY ABOVE NORMAL TEMPS MAY OCCUR OVR INTERIOR CNTRL TOWARD WI BORDER AS DEEP MIXING OFFSETS NORTHERLY WINDS. PRIME ISSUE THROUGH THE EXTENDED PERIOD REALLY IS DWPNTS/RH VALUES WITH THE DRY HIGH DOMINATING. CORE OF DRIEST AIR IS OVER THE AREA THURSDAY NIGHT THROUGH MONDAY. LOWERED DWPNTS MORE TOWARD MIXED LAYER DWPNT TOOL OUTPUT FOR AFTN HOURS ON FRIDAY...SATURDAY...AND SUNDAY. SIMILAR TO EARLIER THIS WEEK...GIVEN EXTENT OF DRY AIRMASS OVERHEAD /PWATS 10-20 PCT OF NORMAL/...WOULD NOT BE SHOCKED AT ALL TO SEE AFTN DWPNTS NEAR 0F AND RH VALUES WELL BLO 20 PCT. NNW GRADIENT WINDS STRONGEST ON FRIDAY AFTN OVR EAST HALF...SO THAT IS PROBABLY WHEN FIRE WX ISSUES WOULD BE MAXIMIZED. OTHERWISE...THROUGH THE WEEKEND...WINDS BECOME PRETTY LIGHT AS HIGH PRESSURE RIDGE AXIS IS OVERHEAD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 740 PM EDT WED APR 25 2012 PER SATELLITE AND RADAR IMAGERY...VIGOROUS DISTURBANCE DROPPING SE THRU NRN ONTARIO TOWARD LAKE SUPERIOR WILL BRING -SHRA TO KIWD/KCMX/KSAW TONIGHT. BASED ON UPSTREAM OBS...EXPECT CIGS TO DROP TO MVFR SOON AFTER THE -SHRA BEGIN. VIS SHOULD GENERALLY REMAIN VFR AS PCPN WILL MOSTLY BE LIGHT. ONCE ASSOCIATED COLD FRONT PASSES AND WINDS SHIFT NORTHERLY/INCREASE...NOT OUT OF THE QUESTION THAT A PERIOD OF IFR CIGS COULD OCCUR OVERNIGHT...ESPECIALLY AT KIWD/KSAW SINCE WINDS AT THOSE SITES WILL HAVE A MORE DIRECT UPSLOPE COMPONENT. -SHRA WILL MIX WITH OR CHANGE TO -SHSN LATE IN THE NIGHT AS COLDER AIR SURGES INTO THE AREA...BUT PCPN WILL END EARLY TO MID MORNING AS CLOUD DECK THINS UNDER ADVECTION OF DRIER AIR. CLOUDS SHOULD SCATTER OUT OR CLEAR AT KIWD/KCMX BY LATE MORNING...BUT NOT UNTIL EARLY AFTN AT KSAW. IN ADDITION...EXPECT GUSTY WINDS BEHIND FRONT OVERNIGHT THRU AT LEAST MID AFTN THU AS LOW-LEVELS WILL BE UNSTABLE...RESULTING IN EFFICIENT MIXING. GUSTS TO 25-30KT WILL BE COMMON AT KCMX/KSAW...ESPECIALLY AT KSAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 414 PM EDT WED APR 25 2012 LOW PRESSURE OVER IOWA WILL SLIDE SE TONIGHT AND DRAG A SFC TROUGH SE ACROSS LAKE SUPERIOR. STRONG CANADIAN HIGH TRIES TO PUSH IN BEHIND IT AND WILL LEAD TO GUSTY NNW WINDS LATE TONIGHT INTO THURS MORNING. EXPECT A FEW GALE FORCE GUSTS TO 35KTS OVER CNTRL/ERN LK SUPERIOR WITH THIS STRONG GRADIENT. CONSIDERED PUTTING UP A GALE FOR A COUPLE HOUR PERIOD AS THIS BOUNDARY MOVES ACROSS LK SUPERIOR...BUT WITH THE SHORT TIME PERIOD...OPTED TO MENTION THE GUSTS AT THIS TIME. THE CANADIAN HIGH PRESSURE RIDGE WILL THEN MOVE OVER THE UPPER GREAT LKS BY THURS NIGHT DIMINISHING THE WINDS BELOW 20KTS. THIS WILL CONTINUE THROUGH MONDAY...AS THE HIGH MOVES SOUTHEAST ACROSS THE GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SHORT TERM...SRF LONG TERM...JLA AVIATION...ROLFSON MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 AM EDT TUE APR 24 2012 .SYNOPSIS... ISSUED AT 414 PM EDT MON APR 23 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A HIGH AMPLITUDE PATTERN WITH A MID/UPPER LEVEL RIDGE OVER THE WRN CONUS AND A TROUGH OVER THE EAST RESULTING IN CONFLUENT NRLY FLOW THROUGH THE UPPER GREAT LAKES. AN UPSTREAM SHORTWAVE TROUGH MOVING INTO NRN MANITOBA SUPPORTED AN EXTENSIVE AREA OF CLOUDS AND A FEW LIGHT SHOWERS. AT THE SFC...THE GRADIENT WAS INCREASING BTWN LOW PRESSURE OVER ERN NY AND A RIDGE OVER THE UPPER MS VALLEY. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 414 PM EDT MON APR 23 2012 AS THE SHORTWAVE TROUGH MOVES TOWARD THE AREA...EXPECT MID CLOUDS TO INCREASE LATE TONIGHT. THE GFS WAS MORE AGGRESSIVE WITH 290K ISENTROPIC LIFT AND PCPN POTENTIAL COMPARED TO THE REST OF THE MODELS. SO...GIVEN THE LACK OF MOISTURE AVBL AND THE RELATIVELY MODEST DYNAMICS...ONLY SLIGHT CHANCE POPS WERE INCLUDED OVER WEST. SOME INLAND TEMPS MAY FALL TO NEAR FREEZING BUT SOUNDINGS SUGGEST THAT PCPN TYPE WOULD BE RAIN. RELATIVELY POOR RH RECOVERY IS EXPECTED OVERNIGHT ACROSS THE AREA...BUT MOST SIGNIFICANTLY OVER THE EASTERN HALF. EVEN WITH THE LOSS OF DAYTIME HEATING/MIXING 9250 MB WINDS IN THE 40 TO 45 KT RANGE...FROM 03Z TO 15Z TUESDAY. AFTER AREAS OF CLOUDS WITH THE SHRTWV MOVE OUT BY AFTERNOON...SUNSHINE AND MIXING SHOULD AGAIN DROP DEWPOINTS BLO GUIDANCE TO AROUND 20F. WITH TEMPERATURES INTO THE MID AND UPPER 50S...RH VALUES NEAR 25 PCT WILL AGAIN LEAD TO ELEVATED WILD FIRE RISK. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 414 PM EDT MON APR 23 2012 LOW PRESSURE SYSTEM CURRENTLY OVER NEW YORK WILL BE LOCATED OVER WRN QUEBEC AT THE START OF THE PERIOD AND WILL PUSH N AND WEAKEN WHILE THE UPPER RIDGE THAT HAS BEEN OVER THE WRN CONUS APPROACHES THE WRN GREAT LKS. WEAK SHORTWAVE MOVING THROUGH THE NW FLOW ALOFT ON TUES NIGHT INTO WED...WHILE ASSOCIATED SFC LOW SLIDES FROM THE DAKOTAS TOWARDS THE LOWER GREAT LAKES. BROAD H850-500 WAA...Q-VECTOR CONV...AND MOISTURE PUSHING IN SLOWLY TUES EVENING AND CONTINUES THROUGH WED. ECMWF FARTHEST SW WITH THE BEST WAA...WHILE NAM/GFS/GEM ALL TRY TO FOCUS A STRONGER AREA OF WAA OVER THE NRN CWA ON WED. THESE DIFFERENCES LEAD TO SOME UNCERTAINTY ON THE EXACT LOCATION OF THE RAIN. IN ADDITION...DRY AIR BELOW H800 WILL TRY TO LIMIT PCPN CHANCES THROUGH MUCH OF THE OVERNIGHT HOURS OVER THE FAR WRN CWA. ATMO DOESN/T REALLY SEEM TO MOISTEN UP UNTIL DAYLIGHT HOURS ON WED. THIS DELAYED MOISTENING WILL LIMIT PCPN ACROSS THE REST OF THE CWA FOR THE FIRST PART OF WED. HAVE TRIED TO PUT SOME TIMING IN FOR THIS DRY AIR HOLDING OFF PCPN. EVEN WITH THE DRY AIR...SEEM TO HAVE ENOUGH SIGNALS TO BUMP CHANCE POPS UP A LITTLE MORE...ESPECIALLY OVER THE WRN CWA DURING THE DAY WED. THE INITIAL DRY AIR AND POSITIONING OF THE PCPN PROVIDES A LITTLE TOO MUCH UNCERTAINTY TO BUMP THEM UP TO LIKELY VALES. MUCH STRONGER WAVE AND ASSOCIATED HEIGHT FALLS ARRIVES LATE WED NIGHT AND THURS MORNING...WHICH BRING THE MUCH COOLER H850 TEMPS TO THE AREA. THE COLD AIR ON THE BACK SIDE OF THE SYSTEM COULD LEAD TO LK ENHANCED CLOUDS/PCPN LINGERING BEHIND THE WAVE INTO THURS MORNING. NAM HOLDING ON TO THE LLVL MOISTURE THROUGH THE MORNING HOURS BEFORE THE DRIER AIR AND SUBSIDENCE FROM THE HIGH PRESSURE RIDGE START TO TAKE OVER. WITH THE NRLY FLOW OVER THE AREA DURING THE MORNING...COMBINING WITH A BRIEF OVERLAP OF THE H850 TEMPS TO -8C AND MOISTURE...THINK THERE WILL BE A BRIEF PERIOD OF STRONGER RAIN/SNOW SHOWERS OVER THE NCNTRL UPSLOPE LOCATIONS MAINLY FROM 06-15Z. MAIN CONCERN WITH SNOW IS THAT THE LLVL TEMPS MIGHT NOT GET COLD ENOUGH TO SUPPORT SNOW UNTIL THE BEST MOISTURE DEPARTS. THUS...DELAYED THE SNOW CHANGE OVER TO OCCUR LATER IN THE NIGHT AND DURING THE FIRST PART OF THURS MORNING. SNOW WILL OCCUR A LITTLE EARLY OVER THE NW HALF OF THE CWA...BUT BOTH CASES WILL NEED A LITTLE WHILE TO COOL CLOUD TEMPS AND GET ICE CRYSTALS BACK IN THE CLOUD DUE TO THE DRY H750 AIR ARRIVING WED EVENING. WITH THE HIGH PRESSURE RIDGE QUICKLY MOVING IN ON THURS AND LLVL MOISTURE DEPARTING FOR ALL BUT FAR ERN UPPER MI...WILL DECREASE THE CLOUDS ACROSS THE AREA EVEN THOUGH H850 TEMPS ARE STILL AROUND -6 OR -7C. COULD BE A LITTLE GUSTY WITH THE STRONG PRESSURE GRADIENT LATE WED NIGHT INTO THURS. WITH THE COLD AIR ARRIVING AND H925 WINDS TO 30KTS...SHOULD SEE GUSTS IN THE 30-35MPH RANGE NEAR LK SUPERIOR IN THE MORNING AND THEN DIMINISHING FORM WEST TO EAST THROUGH THE DAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1241 AM EDT TUE APR 24 2012 VFR CONDITIONS SHOULD REMAIN THROUGH THE NEXT 24 HOURS AT ALL SITES. A WEATHER SYSTEM APPROACHING ON WED WILL BRING SOME MID CLOUDS INTO THE AREA TUE NIGHT. GUSTY WINDS OFF THE SFC AT KSAW WILL CAUSE LLWS OVERNIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 414 PM EDT MON APR 23 2012 A STRONG LOW PRESSURE SYSTEM WILL MOVE NNE INTO THE ERN GREAT LAKES BY THIS EVENING. THIS HAS RESULTED IN INCREASING NNW WINDS...UP TO 30KTS OVER ERN LK SUPERIOR WHICH WILL CONTINUE INTO TUESDAY MORNING. A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE UPPER LAKES ON WED WHILE BEFORE STRONG HIGH PRESSURE BUILDS FROM CENTRAL CANADA INTO THE GREAT LAKES WEDNESDAY NIGHT INTO THURSDAY. THE STRONG GRADIENT BETWEEN THESE SYSTEMS WILL LEAD TO NORTHERLY GUSTS UP TO 30KTS OVER CENTRAL AND EASTERN LAKE SUPERIOR WEDNESDAY NIGHT INTO THURSDAY MORNING. A FEW GALE FORCE GUSTS TO 35KTS ARE ALSO POSSIBLE DURING THIS TIME. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB EXTENDED...JMW AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
213 PM CDT TUE APR 24 2012 .UPDATE... .AVIATION.../18Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED THROUGH THE PERIOD. THE BIGGEST CONCERN IS THE CHANCE OF THUNDERSTORMS FOR THE WESTERN PART OF THE STATE LATE TONIGHT. WARM ADVECTION BEGINS LATE TONIGHT WITH THE INSTABILITY GRADIENT INITIALLY STRONGEST OVER THAT AREA OF THE STATE. WILL JUST INCLUDE A VCTS AT KAXN AT THIS TIME. OTHERWISE AREAS OF SHOWERS WITH LOWER END VFR CIGS /050-060/ SPREADING ACROSS OTHER TAF SITES LATE TONIGHT AND WEDNESDAY MORNING. WILL NEED TO WATCH THE POSSIBILITY OF THUNDER OTHER SITES IN LATER FORECASTS. WINDS GENERALLY EAST TO SOUTHEAST 5 TO 10 KNOTS...BUT SWITCHING TO NORTHWEST NEAR THE END OF THE PERIOD VCNTY OF KAXN AND KRWF. KMSP...JUST SCT MID AND HIGH CLOUDS FOR THE AFTERNOON AND EVENING...THEN INCREASING CHANCE OF SHOWERS AFTER 09Z WITH LOWER END VFR CIGS / 050-060 /. HAVE NOT INCLUDED THUNDER AT THIS POINT BUT SOMETHING TO WATCH IN LATER FORECASTS. COLD FRONT TO MOVE INTO THE AREA AFTER 21Z WITH A WIND SHIFT TO THE NORTHWEST. OTHERWISE GENERALLY EAST TO SOUTHEAST 5 TO 10 KNOTS BUT SOME INCREASE 10 TO 15 KNOTS WEDNESDAY MORNING. && .DISCUSSION... STRONG MID LEVEL TEMPERATURE GRADIENT ACROSS THE AREA THIS MORNING BETWEEN ERN TROUGH AND WRN RIDGE HAS RESULTED IN A NICE BAND OF WAA/ISENTROPICALLY INDUCED MID LEVEL CLOUD COVER ACROSS ERN HALF OF THE MPX AREA. LAPS SOUNDINGS ACROSS THE AREA SHOW AIR BELOW H7 IS QUITE DRY...WHICH IS REFLECTED IN CLOUD HEIGHT AOA 8K FT. STILL...A FEW 50 DBZ PIXELS IN SHOWERS FROM TIME TO TIME IS AN INDICATION THAT ENOUGH PRECIP IS BEING GENERATED TO GET SOME BRIEF SHOWERS TO THE GROUND. HRRR REFLECTIVITY FORECASTS HANDLING THESE SHOWERS WELL THIS MORNING...AND HAS MOST OF THEM GONE BY 12Z AS AREA OF ISENTROPIC LIFT PUSHES SOUTH...SO LEFT NOTHING MORE THAN A SPRINKLE MENTION ACROSS ERN MN THROUGH 15Z. FOR THE REST OF TODAY...THERMAL GRADIENT AND UPPER JET CONFIGURATION WILL REMAIN IN PLACE...WHICH MAY RESULT IN CLOUDS REMAINING ACROSS WRN WI MUCH OF THE DAY. FOR HIGHS...SEEING A STRONG PUSH OF WARM AIR AT H85...BUT WITH THE DEEP AND COLD TROUGH TO THE EAST...DOES LOOK LIKE WARMER AIR DOES GET SLOWED UP SOME...WITH HIGHS IN WI LIKELY ONLY GETTING TO AROUND 60...EVEN IF THE CLOUDS CAN CLEAR OUT THIS AFTERNOON. OUT IN WRN MN...SHOULD SEE MORE WIDESPREAD 70S TODAY...BUT NOT EXPECTING ANY 80 DEGREE READINGS. THE +20C ISOTHERM AT H85 WAS A FAIRLY GOOD DEMARCATION FOR WHERE 80 DEGREE HIGHS WERE OBSERVED YESTERDAY...AND ALL MODELS KEEP THAT WEST OF MN TODAY. FOR TONIGHT AND WEDNESDAY...MODELS CONTINUE TO ADVERTISE THE WRN RIDGE FLATTENING OUT SOME...WITH SHORTWAVE ENERGY AND ASSOCIATED THUNDERSTORMS CURRENTLY NEAR THE IDAHO CHIMNEY DRIVING A SFC LOW ACROSS MN. STILL EXPECTING A STRONG WAA PUSH ALONG AND NORTH OF THE LOW TRACK...WHICH THE SREF/ECMWF CONTINUING TO BRING BASICALLY STRAIGHT DOWN I-94...WITH BEST RAINFALL CHANCES ALONG AND NORTH OF THE 94 CORRIDOR AS A RESULT. BEST RAIN CHANCES LOOK TO COME IN AFTER MIDNIGHT...WITH ELEVATED INSTABILITY STILL LOOKING TO BE MORE THAN SUFFICIENT TO CONTINUE THE MENTION OF THUNDER. FOR WEDNESDAY...TO SAY THE FORECAST IS COMPLEX IS AN UNDERSTATEMENT. BY THE AFTERNOON...SFC LOW LOOKS TO BE IN THE RED WING/LA CROSSE AREA AS A POLAR FRONT COMES SURGING SOUTH OUT OF CANADA. ANY PRECIP LOOKS TO CONTINUE TO BE ASSOCIATED WITH THE SFC LOW...BUT WITH THE FRONT COMING SOUTH IN THE AFTERNOON...DOES LOOK LIKE A LOW/TRIPLE POINT WILL BE SETTING UP OVER SE MN. WITH TEMPS WELL INTO THE 70S AND SFC DEWPS IN THE MID 50S AND BULK SHEAR UP AROUND 50 KTS...A SEVERE THREAT WOULD EXIST FOR ANY SFC BASED CONVECTION THAT CAN TAKE HOLD IN THE AFTERNOON. AT THIS POINT...THE BEST THREAT OF SEVERE WEATHER LOOKS TO BE JUST SE OF THE AREA...BUT SPC SREF CONDITIONAL SEVERE WEATHER PROBS FOR WEDNESDAY AFTERNOON DO SPIKE UP IN SE MN...WITH THE DAY2 OUTLOOK BRINGING MARGINAL SEVERE UP INTO THE SE MPX CWA. BESIDE THE THUNDER THREAT...THE TEMPERATURE FORECAST WAS QUITE THE HEADACHE AS WELL. THE 00Z ECMWF HAS HIGHS UP AROUND 80 FROM RWF DOWN TO FAIRMONT...WITH THE LADYSMITH AREA ONLY GETTING TO 50. WINDS AHEAD OF THE POLAR FRONT LOOK TO COME OUT OF THE WSW...SO DOES LOOK LIKE SWRN AREA COULD REALLY WARM UP QUITE A BIT WEDNESDAY...WHILE MOST MODELS SHOW SHOWERS/STATUS HANGING ON MOST OF THE DAY ACROSS WI...WITH TEMPERATURES STRUGGLING TO BUDGE THERE. THE POLAR FRONT LOOKS DRIVE ANY PRECIP SOUTH AND EAST OF THE AREA WEDNESDAY NIGHT. AN UPPER 1030S HIGH OVER HUDSON BAY WILL BE FILTERING MUCH COLDER AND DRIER AIR INTO THE AREA ON THURSDAY....WITH HIGHS ACROSS WRN/SRN MN RUNNING AS MUCH AS 20 DEGREES COLDER ON THURSDAY THAN ON WEDNESDAY. IT IS THE HIGH AND ASSOCIATED DRY AIR THAT WILL PLAY A LARGE ROLE IN NRN EXTENT OF PRECIP FRIDAY INTO SATURDAY. THE 00Z GEM/ECMWF BASICALLY KEEP ALL BUT THE I-90 CORRIDOR DRY DURING THIS PERIOD...WITH THE ECMWF DROPPING DEWPS DOWN INTO THE TEENS AND 20S BY FRIDAY MORNING ACROSS THE AREA. EVEN THE GFS HAS PULLED PRECIP FURTHER SOUTH...WITH THE NE CWA LOOKING TO REMAIN DRY WITH THIS SYSTEM. GIVEN THE STRENGTH OF THE HUDSON HIGH...AND THE REX BLOCK PROGGED TO BE OVER SRN CANADA BY THE END OF THE WEEK...LIKE THE IDEA OF IT BEING DIFFICULT FOR PRECIP TO MAKE IT MUCH FURTHER NORTH THAN THE MN RIVER...SIMILAR TO WHAT WE SAW WITH THE SYSTEM THAT IMPACTED SOUTHERN MN WED NIGHT/THU OF LAST WEEK. WHERE EVER THE RAIN DOES END UP THOUGH...IT DOES LOOK TO BE RATHER RAW...WITH TEMPS LIKELY STRUGGLING INTO THE LOWER 40S. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/JPR
AREA FORECAST DISCUSSION...UPDATED FOR 12Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
545 AM CDT TUE APR 24 2012 .DISCUSSION...ISSUED 421 AM CDT STRONG MID LEVEL TEMPERATURE GRADIENT ACROSS THE AREA THIS MORNING BETWEEN ERN TROUGH AND WRN RIDGE HAS RESULTED IN A NICE BAND OF WAA/ISENTROPICALLY INDUCED MID LEVEL CLOUD COVER ACROSS ERN HALF OF THE MPX AREA. LAPS SOUNDINGS ACROSS THE AREA SHOW AIR BELOW H7 IS QUITE DRY...WHICH IS REFLECTED IN CLOUD HEIGHT AOA 8K FT. STILL...A FEW 50 DBZ PIXELS IN SHOWERS FROM TIME TO TIME IS AN INDICATION THAT ENOUGH PRECIP IS BEING GENERATED TO GET SOME BRIEF SHOWERS TO THE GROUND. HRRR REFLECTIVITY FORECASTS HANDLING THESE SHOWERS WELL THIS MORNING...AND HAS MOST OF THEM GONE BY 12Z AS AREA OF ISENTROPIC LIFT PUSHES SOUTH...SO LEFT NOTHING MORE THAN A SPRINKLE MENTION ACROSS ERN MN THROUGH 15Z. FOR THE REST OF TODAY...THERMAL GRADIENT AND UPPER JET CONFIGURATION WILL REMAIN IN PLACE...WHICH MAY RESULT IN CLOUDS REMAINING ACROSS WRN WI MUCH OF THE DAY. FOR HIGHS...SEEING A STRONG PUSH OF WARM AIR AT H85...BUT WITH THE DEEP AND COLD TROUGH TO THE EAST...DOES LOOK LIKE WARMER AIR DOES GET SLOWED UP SOME...WITH HIGHS IN WI LIKELY ONLY GETTING TO AROUND 60...EVEN IF THE CLOUDS CAN CLEAR OUT THIS AFTERNOON. OUT IN WRN MN...SHOULD SEE MORE WIDESPREAD 70S TODAY...BUT NOT EXPECTING ANY 80 DEGREE READINGS. THE +20C ISOTHERM AT H85 WAS A FAIRLY GOOD DEMARCATION FOR WHERE 80 DEGREE HIGHS WERE OBSERVED YESTERDAY...AND ALL MODELS KEEP THAT WEST OF MN TODAY. FOR TONIGHT AND WEDNESDAY...MODELS CONTINUE TO ADVERTISE THE WRN RIDGE FLATTENING OUT SOME...WITH SHORTWAVE ENERGY AND ASSOCIATED THUNDERSTORMS CURRENTLY NEAR THE IDAHO CHIMNEY DRIVING A SFC LOW ACROSS MN. STILL EXPECTING A STRONG WAA PUSH ALONG AND NORTH OF THE LOW TRACK...WHICH THE SREF/ECMWF CONTINUING TO BRING BASICALLY STRAIGHT DOWN I-94...WITH BEST RAINFALL CHANCES ALONG AND NORTH OF THE 94 CORRIDOR AS A RESULT. BEST RAIN CHANCES LOOK TO COME IN AFTER MIDNIGHT...WITH ELEVATED INSTABILITY STILL LOOKING TO BE MORE THAN SUFFICIENT TO CONTINUE THE MENTION OF THUNDER. FOR WEDNESDAY...TO SAY THE FORECAST IS COMPLEX IS AN UNDERSTATEMENT. BY THE AFTERNOON...SFC LOW LOOKS TO BE IN THE RED WING/LA CROSSE AREA AS A POLAR FRONT COMES SURGING SOUTH OUT OF CANADA. ANY PRECIP LOOKS TO CONTINUE TO BE ASSOCIATED WITH THE SFC LOW...BUT WITH THE FRONT COMING SOUTH IN THE AFTERNOON...DOES LOOK LIKE A LOW/TRIPLE POINT WILL BE SETTING UP OVER SE MN. WITH TEMPS WELL INTO THE 70S AND SFC DEWPS IN THE MID 50S AND BULK SHEAR UP AROUND 50 KTS...A SEVERE THREAT WOULD EXIST FOR ANY SFC BASED CONVECTION THAT CAN TAKE HOLD IN THE AFTERNOON. AT THIS POINT...THE BEST THREAT OF SEVERE WEATHER LOOKS TO BE JUST SE OF THE AREA...BUT SPC SREF CONDITIONAL SEVERE WEATHER PROBS FOR WEDNESDAY AFTERNOON DO SPIKE UP IN SE MN...WITH THE DAY2 OUTLOOK BRINGING MARGINAL SEVERE UP INTO THE SE MPX CWA. BESIDE THE THUNDER THREAT...THE TEMPERATURE FORECAST WAS QUITE THE HEADACHE AS WELL. THE 00Z ECMWF HAS HIGHS UP AROUND 80 FROM RWF DOWN TO FAIRMONT...WITH THE LADYSMITH AREA ONLY GETTING TO 50. WINDS AHEAD OF THE POLAR FRONT LOOK TO COME OUT OF THE WSW...SO DOES LOOK LIKE SWRN AREA COULD REALLY WARM UP QUITE A BIT WEDNESDAY...WHILE MOST MODELS SHOW SHOWERS/STATUS HANGING ON MOST OF THE DAY ACROSS WI...WITH TEMPERATURES STRUGGLING TO BUDGE THERE. THE POLAR FRONT LOOKS DRIVE ANY PRECIP SOUTH AND EAST OF THE AREA WEDNESDAY NIGHT. AN UPPER 1030S HIGH OVER HUDSON BAY WILL BE FILTERING MUCH COLDER AND DRIER AIR INTO THE AREA ON THURSDAY....WITH HIGHS ACROSS WRN/SRN MN RUNNING AS MUCH AS 20 DEGREES COLDER ON THURSDAY THAN ON WEDNESDAY. IT IS THE HIGH AND ASSOCIATED DRY AIR THAT WILL PLAY A LARGE ROLE IN NRN EXTENT OF PRECIP FRIDAY INTO SATURDAY. THE 00Z GEM/ECMWF BASICALLY KEEP ALL BUT THE I-90 CORRIDOR DRY DURING THIS PERIOD...WITH THE ECMWF DROPPING DEWPS DOWN INTO THE TEENS AND 20S BY FRIDAY MORNING ACROSS THE AREA. EVEN THE GFS HAS PULLED PRECIP FURTHER SOUTH...WITH THE NE CWA LOOKING TO REMAIN DRY WITH THIS SYSTEM. GIVEN THE STRENGTH OF THE HUDSON HIGH...AND THE REX BLOCK PROGGED TO BE OVER SRN CANADA BY THE END OF THE WEEK...LIKE THE IDEA OF IT BEING DIFFICULT FOR PRECIP TO MAKE IT MUCH FURTHER NORTH THAN THE MN RIVER...SIMILAR TO WHAT WE SAW WITH THE SYSTEM THAT IMPACTED SOUTHERN MN WED NIGHT/THU OF LAST WEEK. WHERE EVER THE RAIN DOES END UP THOUGH...IT DOES LOOK TO BE RATHER RAW...WITH TEMPS LIKELY STRUGGLING INTO THE LOWER 40S. && .AVIATION.../12Z TAF ISSUANCE/ WDLY SCT -SHRA SHUD BE S OF MSP BY 12Z LEAVING SCT TO OCNL BKN CLDS AROUND 10K FOR RMDR OF DAY. SFC WINDS WILL BE LIGHT...GENERALY AOB 10 KTS WHICH WILL CAUSE SOME VARIABILITY IN DIRECTION...ESPECIALLLY AT WI TAFS AND TO SOME EXTEND AT MSP. SCT SHWRS WILL PUSH INTO W MN BY 06Z AND ACRS AREA AROUND 10Z. EXPECT CONDITIONS TO REMAIN VFR...BUT IF SUFFICIENT PCPN COULD SEE HIGH END MVFR ESPECIALLY AT STC/MSP AND WI TAFS LATE IN PRD. MSP...WILL CONTINUE TO SEE SOME VARIABILITY IN WIND DIRECION INTO THE MID MORNING...BUT WINDS WILL GENERALLY BE IN RANGE FROM 080 TO 130. SCT -SHWRS WILL BE S OF MSP BY 12Z LEAVING SCT-BKN100 FOR THE DAY. COULD SEE HIGH END MVFR CONDS AFTER 10Z IN SHWRS. //OUTLOOK...TUESDAY NIGHT THROUGH SUNDAY... .WED...CHANCE OF -SHRA/-TSRA INTO WEDNESDAY WITH MVFR CIGS/VSBY POSSIBLE. .WED NIGHT AND THU...VFR UNDER HIGH PRESSURE. .THU NIGHT THRU SUN...CHC OF -SHRA BUT MAINLY VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/BAP
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
421 AM CDT TUE APR 24 2012 .DISCUSSION... STRONG MID LEVEL TEMPERATURE GRADIENT ACROSS THE AREA THIS MORNING BETWEEN ERN TROUGH AND WRN RIDGE HAS RESULTED IN A NICE BAND OF WAA/ISENTROPICALLY INDUCED MID LEVEL CLOUD COVER ACROSS ERN HALF OF THE MPX AREA. LAPS SOUNDINGS ACROSS THE AREA SHOW AIR BELOW H7 IS QUITE DRY...WHICH IS REFLECTED IN CLOUD HEIGHT AOA 8K FT. STILL...A FEW 50 DBZ PIXELS IN SHOWERS FROM TIME TO TIME IS AN INDICATION THAT ENOUGH PRECIP IS BEING GENERATED TO GET SOME BRIEF SHOWERS TO THE GROUND. HRRR REFLECTIVITY FORECASTS HANDLING THESE SHOWERS WELL THIS MORNING...AND HAS MOST OF THEM GONE BY 12Z AS AREA OF ISENTROPIC LIFT PUSHES SOUTH...SO LEFT NOTHING MORE THAN A SPRINKLE MENTION ACROSS ERN MN THROUGH 15Z. FOR THE REST OF TODAY...THERMAL GRADIENT AND UPPER JET CONFIGURATION WILL REMAIN IN PLACE...WHICH MAY RESULT IN CLOUDS REMAINING ACROSS WRN WI MUCH OF THE DAY. FOR HIGHS...SEEING A STRONG PUSH OF WARM AIR AT H85...BUT WITH THE DEEP AND COLD TROUGH TO THE EAST...DOES LOOK LIKE WARMER AIR DOES GET SLOWED UP SOME...WITH HIGHS IN WI LIKELY ONLY GETTING TO AROUND 60...EVEN IF THE CLOUDS CAN CLEAR OUT THIS AFTERNOON. OUT IN WRN MN...SHOULD SEE MORE WIDESPREAD 70S TODAY...BUT NOT EXPECTING ANY 80 DEGREE READINGS. THE +20C ISOTHERM AT H85 WAS A FAIRLY GOOD DEMARCATION FOR WHERE 80 DEGREE HIGHS WERE OBSERVED YESTERDAY...AND ALL MODELS KEEP THAT WEST OF MN TODAY. FOR TONIGHT AND WEDNESDAY...MODELS CONTINUE TO ADVERTISE THE WRN RIDGE FLATTENING OUT SOME...WITH SHORTWAVE ENERGY AND ASSOCIATED THUNDERSTORMS CURRENTLY NEAR THE IDAHO CHIMNEY DRIVING A SFC LOW ACROSS MN. STILL EXPECTING A STRONG WAA PUSH ALONG AND NORTH OF THE LOW TRACK...WHICH THE SREF/ECMWF CONTINUING TO BRING BASICALLY STRAIGHT DOWN I-94...WITH BEST RAINFALL CHANCES ALONG AND NORTH OF THE 94 CORRIDOR AS A RESULT. BEST RAIN CHANCES LOOK TO COME IN AFTER MIDNIGHT...WITH ELEVATED INSTABILITY STILL LOOKING TO BE MORE THAN SUFFICIENT TO CONTINUE THE MENTION OF THUNDER. FOR WEDNESDAY...TO SAY THE FORECAST IS COMPLEX IS AN UNDERSTATEMENT. BY THE AFTERNOON...SFC LOW LOOKS TO BE IN THE RED WING/LA CROSSE AREA AS A POLAR FRONT COMES SURGING SOUTH OUT OF CANADA. ANY PRECIP LOOKS TO CONTINUE TO BE ASSOCIATED WITH THE SFC LOW...BUT WITH THE FRONT COMING SOUTH IN THE AFTERNOON...DOES LOOK LIKE A LOW/TRIPLE POINT WILL BE SETTING UP OVER SE MN. WITH TEMPS WELL INTO THE 70S AND SFC DEWPS IN THE MID 50S AND BULK SHEAR UP AROUND 50 KTS...A SEVERE THREAT WOULD EXIST FOR ANY SFC BASED CONVECTION THAT CAN TAKE HOLD IN THE AFTERNOON. AT THIS POINT...THE BEST THREAT OF SEVERE WEATHER LOOKS TO BE JUST SE OF THE AREA...BUT SPC SREF CONDITIONAL SEVERE WEATHER PROBS FOR WEDNESDAY AFTERNOON DO SPIKE UP IN SE MN...WITH THE DAY2 OUTLOOK BRINGING MARGINAL SEVERE UP INTO THE SE MPX CWA. BESIDE THE THUNDER THREAT...THE TEMPERATURE FORECAST WAS QUITE THE HEADACHE AS WELL. THE 00Z ECMWF HAS HIGHS UP AROUND 80 FROM RWF DOWN TO FAIRMONT...WITH THE LADYSMITH AREA ONLY GETTING TO 50. WINDS AHEAD OF THE POLAR FRONT LOOK TO COME OUT OF THE WSW...SO DOES LOOK LIKE SWRN AREA COULD REALLY WARM UP QUITE A BIT WEDNESDAY...WHILE MOST MODELS SHOW SHOWERS/STATUS HANGING ON MOST OF THE DAY ACROSS WI...WITH TEMPERATURES STRUGGLING TO BUDGE THERE. THE POLAR FRONT LOOKS DRIVE ANY PRECIP SOUTH AND EAST OF THE AREA WEDNESDAY NIGHT. AN UPPER 1030S HIGH OVER HUDSON BAY WILL BE FILTERING MUCH COLDER AND DRIER AIR INTO THE AREA ON THURSDAY....WITH HIGHS ACROSS WRN/SRN MN RUNNING AS MUCH AS 20 DEGREES COLDER ON THURSDAY THAN ON WEDNESDAY. IT IS THE HIGH AND ASSOCIATED DRY AIR THAT WILL PLAY A LARGE ROLE IN NRN EXTENT OF PRECIP FRIDAY INTO SATURDAY. THE 00Z GEM/ECMWF BASICALLY KEEP ALL BUT THE I-90 CORRIDOR DRY DURING THIS PERIOD...WITH THE ECMWF DROPPING DEWPS DOWN INTO THE TEENS AND 20S BY FRIDAY MORNING ACROSS THE AREA. EVEN THE GFS HAS PULLED PRECIP FURTHER SOUTH...WITH THE NE CWA LOOKING TO REMAIN DRY WITH THIS SYSTEM. GIVEN THE STRENGTH OF THE HUDSON HIGH...AND THE REX BLOCK PROGGED TO BE OVER SRN CANADA BY THE END OF THE WEEK...LIKE THE IDEA OF IT BEING DIFFICULT FOR PRECIP TO MAKE IT MUCH FURTHER NORTH THAN THE MN RIVER...SIMILAR TO WHAT WE SAW WITH THE SYSTEM THAT IMPACTED SOUTHERN MN WED NIGHT/THU OF LAST WEEK. WHERE EVER THE RAIN DOES END UP THOUGH...IT DOES LOOK TO BE RATHER RAW...WITH TEMPS LIKELY STRUGGLING INTO THE LOWER 40S. && .AVIATION.../06Z TAF ISSUANCE/ SURFACE HIGH PRESSURE RIDGE...MOVING EAST OVER THE NEXT 12 HOURS. SOME MID/HIGH CLOUDS ASSOCIATED WITH A WEAK WARM AIR ADVECTION...OCCURRING OVER THE UPPER MIDWEST...WILL CONTINUE TO DEVELOP OVER THE FORECAST AREA OVERNIGHT. CLOUDS WILL CONTINUE TO INCREASE AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. A WRM FNT WILL LIFT NORTHEAST FROM THE DAKOTAS TUESDAY AFTERNOON. AS MENTION BEFORE...SFC WINDS WILL BE THE TRICKY PART IN THIS TAF PERIOD...MAINLY DIRECTIONS. MITIGATING THESE CONCERNS IS THAT SPEEDS WILL BE LESS THAN 10 KT THROUGH THE PERIOD. OVERALL...VFR CONDITIONS PREVAIL. MSP...NO PROBLEMS OR CONCERN DURING THE TAF PERIOD. VFR CONDITIONS WILL PREVAIL THROUGH TUESDAY EVENING. CONDITIONS POSSIBLY LOWERING TO MVFR IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. WINDS LIGHT AND VARIABLE OVERNIGHT THEN BECOMING SOUTHEAST 5 TO 10 KNOTS BY TUESDAY EVENING. //OUTLOOK...TUESDAY NIGHT THROUGH SUNDAY... .TUE NIGHT AND WED...CHANCE OF -SHRA/-TSRA LATE TUESDAY NIGHT INTO WEDNESDAY WITH MVFR CIGS/VSBY POSSIBLE. .WED NIGHT AND THU...VFR UNDER HIGH PRESSURE. .THU NIGHT THRU SUN...CHC OF -SHRA THROUGHOUT THE PERIOD AS SEVERAL WAVES OF LOW PRESSURE MOVE THRU THE AREA. OCNL MVFR-IFR CONDITIONS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/JVM
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
824 PM CDT WED APR 25 2012 .UPDATE... ISSUED AT 809 PM CDT WED APR 25 2012 ...SEVERE THUNDERSTORM WATCH 187 IN EFFECT UNTIL 300 AM... A SEVERE THUNDERSTORM HAS DEVELOPED OVER SOUTHEAST IOWA AND IS MOVING THROUGH EXTREME NORTHEAST MISSOURI TOWARD WEST CENTRAL ILLINOIS. DEEP LAYER SHEAR AROUND 50KTS AND MLCAPE OVER 2500 J/KG ACCORDING TO THE RUC IS MORE THAN ENOUGH TO KEEP THIS STORM GOING. CAPE MAY BE OVER DONE DUE TO THE RUC NOT HANDLING THE DEWPOINTS VERY WELL. REGARDLESS...THE STORM IS OBVIOUSLY THERE...AND THERE`S ENOUGH INSTABILITY TO KEEP IT ALIVE AND SEVERE. RUC KEEPS IMPRESSIVE INSTABILITY OVER SOUTHWEST ILLINOIS AT LEAST UNTIL 06Z WITH A RELATIVELY WEAK CAP. WOULD EXPECT THE STORM TO CONTINUE AT LEAST UNTIL THEN...POTENTIALLY EXPANDING IN SIZE AND GROWING INTO A QLCS OR SEVERE CLUSTER. ADDITIONAL THUNDERSTORM DEVELOPMENT LOOKS LIKELY TO THE SOUTHWEST OF THE INITIAL STORM AS THE SURFACE COLD FRONT MOVES THROUGH THE REGION. CARNEY && .SHORT TERM... ISSUED AT 317 PM CDT WED APR 25 2012 (TONIGHT) STILL TRYING TO GET A HANDLE ON THE PRECIPITATION THREAT TONIGHT. PROBLEMS TO DEAL WITH ARE OVERFORECASTING OF THE SURFACE DEW POINTS AND HENCE INSTABILITY BY ALL OF THE MODELS. ALSO WHAT APPEARS TO BE AN OVERLY AGGRESSIVE QPF FORECAST FROM THE GFS AND ECMWF...WHILE THE OTHER MODELS ARE MUCH DRIER...ESPECIALLY THE NAM. THE LATEST WATER VAPOR IMAGERY AND PROFILERS SHOWED SEVERAL WEAK SHORT WAVES WITHIN THE NW FLOW ALOFT...OVER SE IA AND CENTERED THRU NEBRASKA. THE FIRST SHORT WAVE ALONG WITH LOW LEVEL WAA WAS HELPING MAINTAIN SOME SCATTERED HIGH BASED SHOWERS IN NE MO AND WEST CENTRAL IL. A COLD FRONT AND SFC LOW WAS ASSOCIATED WITH THE LATER SHORT WAVE...WITH THE SURFACE LOW IN CENTRAL IOWA AND COLD FRONT TRAILING THRU NW MO INTO KS...WHILE A WARM FRONT STRETCHED FROM THE SURFACE LOW SEWD SNAKING NEAR THE MS RIVER. THE LATEST SFC MESOANALYSIS GRAPHICS SHOWED THE WARM SECTOR WAS STRONGLY CAPPED. EXPECT FOR A SMALL AREA JUST TO THE NW OF ST LOUIS...THE WARM SECTOR WAS STRONGLY CAPPED AS WELL. THE GENERAL TREND SHOULD BE FOR THE SURFACE LOW TO MOVE ESEWD ACROSS CENTRAL IL THIS EVENING AND INTO THE OH VALLEY OVERNIGHT...WITH THE COLD FRONT DROPPING SOUTH THROUGH THE AREA AND WARM FRONT MOVING EAST ACROSS THE IL CWA COUNTIES THIS EVENING. I THINK THE WARM SECTOR WILL LARGELY REMAINED CAPPED AND THE PRECIPITATION THREAT APPEARS QUITE MINIMAL. THE AREA ALONG AND EAST OF THE WARM FRONT APPEARS TO HAVE THE BEST CONVECTIVE POTENTIAL CONSIDERING A WEAKER CAP...THE GREATEST LIFT WILL BE FOCUSED IN THIS ZONE...AND THIS IS THE AREA THROUGH WHICH THE SHORT WAVE WILL TRACK. I HAVE CHANCE POPS ALONG THE MS RIVER INCREASING TO HIGHER CHANCE OVER THE FAR EASTERN CWA. GLASS && .LONG TERM... ISSUED AT 317 PM CDT WED APR 25 2012 (THURSDAY THROUGH WEDNESDAY) FRONTAL BOUNDARY TO SINK SOUTH OF FORECAST AREA BY THURSDAY MORNING WITH SHOWERS AND THUNDERSTORMS COMING TO AN END. NOT A LOT OF COLD AIR BEHIND THIS BOUNDARY...SO HIGHS ON THURSDAY WILL BE IN THE LOW 70S FAR NORTH TO THE LOW 80S FAR SOUTH. THEN ON THURSDAY NIGHT...FRONTAL BOUNDARY TO BEGIN MOVING BACK NORTH AS A WARM FRONT WITH BEST CHANCE OF SHOWERS AND THUNDERSTORMS OVER SOUTHWESTERN AND WESTERN MO...WITH ACTIVITY INCREASING IN COVERAGE ACROSS THE FORECAST AREA ON FRIDAY. LOWS THURSDAY NIGHT WILL BE IN THE MID 40S TO MID 50S...WITH HIGHS ON FRIDAY IN THE MID 50S TO UPPER 60S. BY FRIDAY NIGHT...NEXT IN A SERIES OF SHORTWAVES/SURFACE LOWS TO SLIDE ALONG FRONT WITH SHOWERS AND THUNDERSTORMS LIKELY...MAINLY ALONG AND NORTH OF INTERSTATE 70. THEN FRONTAL BOUNDARY TO SINK SOUTH OF FORECAST AREA DURING THE DAY ON SATURDAY...WITH PRECIPITATION TAPERING OFF ONCE AGAIN. LOWS FRIDAY NIGHT WILL BE IN THE MID 40S TO AROUND 60...THEN HIGHS ON SATURDAY RANGING FROM THE MID 50S FAR NORTH TO THE MID 70S FAR SOUTH. BEYOND THAT...WE REMAIN IN ACTIVE PATTERN WITH CHANCES OF SHOWERS AND THUNDERSTORMS OFF AND ON THROUGH THE REST OF THE FORECAST PERIOD. TEMPS TO REMAIN A BIT COOLER THROUGH MONDAY...BEFORE MODERATING BY MID WEEK WITH HIGHS BACK IN THE MID TO UPPER 70S BY NEXT WEDNESDAY. BYRD && .AVIATION... ISSUED AT 554 PM CDT WED APR 25 2012 NO SIGNIFICANT CHANGES TO PREVIOUS THINKING. SCATTERED TSRA THAT DEVELOPED OVER CENTRAL ILLINOIS EARLIER HAS WEAKENED AND BELIEVE THE POTENTIAL FOR SHRA/TSRA AFFECTING ANY OF THE TERMINALS IS MINIMAL THIS EVENING. IF THERE IS REDEVELOPMENT...IT WILL LIKELY BE TO THE EAST OF THE ST. LOUIS METRO AREA SITES BETWEEN 00-02Z. OTHERWISE EXPECT DRY AND VFR CONDITIONS THROUGH THE PERIOD. COLD FRONT WILL MOVE SOUTHEAST ACROSS THE TAF SITES THIS EVENING CAUSING A WIND SHIFT FROM THE NORTHWEST. WINDS WILL SHOW A VERY SLOW VEERING TO THE NORTHEAST BY LATE THURSDAY AFTERNOON/EVENING. SPECIFICS FOR KSTL...AS MENTIONED ABOVE...EXPECT THE TERMINAL TO REMAIN DRY THIS EVENING AS ANY TSRA DEVELOPMENT WILL LIKELY OCCUR OVER IL THROUGH 02Z. WINDS WILL TURN OUT OF THE NORTHWEST BEHIND A COLD FROPA AROUND 06Z. DRY AND VFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD WITH SURFACE WINDS SLOWLY VEERING SURFACE WINDS. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
346 PM CDT Tue Apr 24 2012 .DISCUSSION... In the short term, primary concerns remain with slight convective chances through Wednesday along with temperatures. This afternoon, pesky altocumulus and cirrostratus have limited the upwards extend of temperatures to some degree. However, many areas will still climb nearly 10-15 degrees above seasonal normals. The warmest temperatures this afternoon have been located over central Kansas and southern Nebraska where many locations are now in the middle 90s. This airmass will gradually move eastward during the overnight hours. Tonight: 18z NAM, high-res WRF and HRRR continue to generate isolated to scattered showers or thunderstorms late tonight across central and southeastern Kansas along with western Missouri. This activity seems to be tied to a weak shortwave expected to cross eastward out of the central Rockies overnight. A slightly amplified low level jet will push an additional surge of mid-level moisture eastward, with an increase in elevated instability above 600 mb. An incredibly dry lower half of the troposphere should limit widespread precipitation, but if a thunderstorm could form would have to watch for the potential for some sort of stronger wind gust or heat burst. Wednesday: GFS which has handled today`s cloud cover adequately well is less bullish with mid-level cloud cover with EML shifting further east. Mid-level AC may fester Wednesday morning in central Missouri, delaying the rapid warmup. However, the remainder of the CWA will be highly capped, allowing for a significant warmup to near record levels in some locations. Fast moving shortwave trough will race into the western Great Lakes late Wednesday afternoon with a ill-defined surface trough over northern Missouri. Models still point to little in the way of development along this boundary as best dynamics are focused in the Great Lakes with the progressive shortwave. There may be enough surface convergence for a slightly higher chance for late afternoon or evening thunderstorms in northeastern Missouri. Wednesday night and Thursday: Models have again shifted the surface boundary a bit further south into central Missouri Wednesday night, with an slightly stronger influence from cooler Canadian air possible. Northeast winds should hold temperatures still above normal, but will lower temperatures a few degrees Thursday. By Thursday night, the next round of warm advection precipitation should begin as the next upper low begins to eject out of the southwestern United States. Dux Medium Range (Friday through Tuesday)... A quick deamplification of the upper pattern will bring about a more progressive and stormier pattern for the extended period. As upper ridging breaks down over the Midwest, a weak negatively-tilted shortwave will eject into the Plains early Friday, and quickly deamplify as it becomes absorbed by mean Great Lakes troughing on Saturday. The result will be a quickly filling surface low that is forecast to track across southern or central Missouri Friday night. Going off the more stable GFS solution suggests a more progressive and southerly forecast track that keeps much of the forecast area in the cool sector on Friday. This solution is backed up by the latest NAM which is even further south. This also sets up a tight baroclinic region marking the difference between temperatures near 50 across the north and in the mid 70s south. Bulk of precipitation Friday and Friday night will be focused near and just north of this boundary, which looks to set up near or just south of the US 50 corridor. Can`t rule out some elevated small hailers on Friday but any appreciable severe threat will remain south of the boundary, and capping may keep that threat to a minimum. Continued to lean toward the more progressive GFS solution for Saturday and Sunday so brought PoPs lower than consensus numbers for this period. In continued quasizonal flow, the next wave to impact the region will arrive Monday night and Tuesday. Surface baroclinic region will remain south of the region through early next week maintaining below average temperatures through the period. Hawblitzel && .CLIMATE... Record highs for Wednesday: CITY...........NORMAL HIGH........RECORD HIGH KANSAS CITY....69 DEGREES.........91 IN 1989 ST. JOESPH.....68 DEGREES.........92 IN 1989 DUX && .AVIATION... For the 18Z TAFs: VFR conditions are expected over the terminals through Wednesday morning. Edge of warm air aloft continues to push eastward over the terminals resulting in scattered mid-level clouds through the overnight hours. It is possible to have a few high based showers or even thunderstorms later tonight as the low level jet increases. However, probability of impacting the terminals is too low to include at this time. Winds are expected to turn more southerly tonight, before veering back to the southwest for the daytime hours of Wednesday. Dux && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 PM CDT WED APR 25 2012 .AVIATION...00Z TAF. AT THIS POINT...IT APPEARS VFR CONDITIONS WILL HOLD THIS FORECAST PERIOD. PRIMARILY LOOKING FOR GRADUAL INCREASE IN CLOUDS THROUGH THE LAST 18 HOURS OF THE FORECAST... WITH CEILINGS REMAINING ABOVE 8K. WINDS WILL TURN TO THE EAST EVENTUALLY AS HIGH PRESSURE TO THE NORTH CONTINUES TO INFLUENCE THE AREA. && .PREV DISCUSSION... /ISSUED 405 PM CDT WED APR 25 2012/ SHORT TERM...THROUGH THURSDAY AFTERNOON. PRIMARY CONCERN IN THE NEXT 24 HOURS IS HOW MUCH OF THE CWA STANDS TO SEE MEASURABLE RAINFALL...AND THE MAIN THEME HERE IS THAT THESE CHANCES CONTINUE TO DECREASE IN MOST AREAS...WITH MUCH BETTER CHANCES HOLDING OFF UNTIL THE THURSDAY NIGHT PERIOD AS DISCUSSED IN THE LONG TERM SECTION BELOW. ALSO...ALL MENTION OF THUNDERSTORMS HAS BEEN PULLED THROUGH THURSDAY AFTERNOON THANKS TO VERY MEAGER INSTABILITY. 19Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK 1000MB LOW OVER CENTRAL IA...WITH A TROUGH AXIS/WEAK COLD FRONT TRAILING SOUTHWESTWARD ACROSS EASTERN/SOUTH CENTRAL KS. IN THE WAKE OF THIS BOUNDARY...NORTH BREEZES GUSTING TO AROUND 30 MPH AND LOCALLY HIGHER HAVE BEEN COMMON ACROSS THE CWA THIS AFTERNOON. DESPITE NEUTRAL TO EVEN WEAK COLD AIR ADVECTION EVIDENT AT 850MB...TEMPS HAVE AGAIN SOARED TO AT LEAST NEAR-RECORD LEVELS IN MANY CENTRAL/SOUTHERN COUNTIES THANKS TO DEEP MIXING INTO THE 750-700MB RANGE PER FORECAST SOUNDINGS. SLIGHTLY COOLER TEMPS HAVE TAKEN HOLD IN THE NORTHWESTERN CWA...RESULTING IN A RANGE FROM LOW-MID 80S NORTHWEST TO MAINLY LOW 90S SOUTHEAST. UNLIKE YESTERDAY..IT APPEARS TRI-CITIES TEMP RECORDS FOR THE DAY ARE LIKELY SAFE. LOOKING ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM A BROAD RIDGE CENTERED OVER THE ROCKIES...WITH AN UPSTREAM TROUGH AND CLOSED 500MB LOW APPROACHING THE SOUTHERN CAL COAST. A SUBTROPICAL MOISTURE PLUME IN THE MID/UPPER LEVELS IS RIDING AROUND THE TOP OF THE RIDGE AND HAS RESULTED IN A FAIRLY THICK BUT NARROW PLUME OF CIRRUS OVERSPREADING MUCH OF THE SOUTHWEST 1/2 OF THE CWA TODAY. MEANWHILE...SOME HIGH BASED CUMULUS AND EVEN SOME WEAK THUNDERSHOWERS ARE POPPING AT THIS HOUR ALONG AN AXIS FROM THE WESTERN NEBRASKA SANDHILLS BACK UP INTO THE BLACK HILLS. LATE THIS AFTERNOON THROUGH AT LEAST MIDNIGHT...THE VAST MAJORITY...IF NOT THE ENTIRE CWA WILL STAY DRY AS THE AIRMASS OVER THE LOCAL AREA IS QUITE CAPPED TO LOW-LEVEL PARCELS. HOWEVER...AM A BIT WARY THAT A LIGHT SHOWER OR MAYBE EVEN A WEAKENING THUNDERSTORM OR TWO COULD TRY MAKING AN RUN AT A FEW OF THE NORTHWEST COUNTIES IN THE 22Z-02Z TIME FRAME...AS ACTIVITY DEVELOPING IN THE VERY STEEP LOW LEVEL LAPSE RATE ENVIRONMENT OFF THE SANDHILLS DRIFTS SOUTHEAST. THIS ACTIVITY IS WELL CAPTURED BY THE LATEST HRRR RUNS...BUT EVEN THIS MODEL...WHICH IS MOST AGGRESSIVE WITH THIS ACTIVITY FADES MOST OF IT OUT BEFORE IT ENTERS THE NORTHWEST COUNTIES. EVENING SHIFT WILL HAVE TO KEEP AN EYE ON THIS...BUT AM GOING TO ONLY GO WITH A SLIGHT CHANCE SPRINKLE MENTION FOR NOW...AND ASSUME THAT ANY HEAVIER SHOWERS OR WEAK THUNDERSTORMS LOSE STEAM BEFORE THEY WOULD GET IN. TURNING TO THE POST-MIDNIGHT HOURS...PULLED THUNDERSTORM MENTION ALTOGETHER...AND EVEN PULLED MEASURABLE POPS...LEAVING ONLY A SLIGHT CHANCE SPRINKLE MENTION IN FAR WESTERN COUNTIES AFTER 08Z. INSTABILITY IS VIRTUALLY NON-EXISTENT LATE TONIGHT...AND THE ONLY FORCING FOR PRECIP WILL BE A GRADUAL MID-LEVEL TOP-DOWN MOISTENING FROM WEST TO EAST EVIDENT IN THE DEWPOINT AND RH FIELD AT 700MB ON MODELS SUCH AS THE 12Z NAM. BETTER CHANCES FOR MEASURABLE LIGHT SHOWERS LATE TONIGHT WILL CERTAINLY RESIDE JUST WEST OF THE CWA OVER THE GLD FORECAST AREA. OTHERWISE...WINDS THIS EVENING WILL QUICKLY DIMINISH...WITH LIGHT FLOW GRADUALLY TURNING FROM NORTHERLY TO EASTERLY AS A SURFACE RIDGE AXIS CENTERED WELL TO THE NORTH MIGRATES EASTWARD. CHANGED LOW TEMPS LITTLE FROM PREVIOUS FORECAST...AND WITH MID LEVEL CLOUDS ON THE INCREASE...WILL KEEP THINGS GENERALLY 2-3 DEGREES ABOVE MET/MAV GUIDANCE CONSENSUS...BOTTOMING OUT MOST OF THE CWA BETWEEN 54-58 DEGREES. ON THURSDAY...THE HEART OF THE MID/UPPER RIDGE AXIS WILL PASS OVERHEAD...AS THE UPSTREAM COMPACT BUT STRONG CLOSED LOW GRADUALLY MIGRATES FROM NEAR THE FAR SOUTHERN TIP OF CAL AT 12Z TO NEAR THE 4-CORNERS BY 00Z. WITH THIS FEATURE REMAINING WELL OFF TO THE SOUTHWEST OF THE CWA...APPRECIABLE FORCING WILL REMAIN WEAK...DESPITE INCREASING MID/HIGH LEVEL CLOUD COVER AND WEAK FORCING ASSOCIATED WITH A SUBTLE LEAD WAVE. THE 12Z NAM WAS QUITE SUPPORTIVE OF PULLING THUNDER MENTION...WITH EVEN ELEVATED CAPE NEGLIGIBLE. HOWEVER...WILL FOLLOW NAM SOLUTION FAIRLY CLOSELY...WITH BEST CHANCE FOR LIGHT SHOWERS FOCUSED ACROSS THE NORTHWEST 1/4 OF THE CWA AS WEAK LIFT FROM THE LEAD SHORTWAVE KEEPS MID LEVEL THETA-E ADVECTION ALIVE. EVEN OUTSIDE THIS MOST FAVORED AREA...KEPT AT LEAST A SLIGHT CHANCE POP OR A SPRINKLE MENTION GOING CWA-WIDE ESPECIALLY DURING THE AFTERNOON...BUT WOULD BE SURPRISED TO SEE MOST AREAS MEASURE MORE THAN A FEW HUNDREDTHS OF AN INCH...AND A GOOD PERCENTAGE OF THE AREA LIKELY STAYING DRY. TEMPS WILL BE A BIT TRICKY...WITH PLENTIFUL CLOUD COVER AND INCREASING EASTERLY WINDS INTO THE 15-20 MPH RANGE DURING THE AFTERNOON. IT WILL CERTAINLY BE COOLER THAN THESE PAST FEW DAYS THOUGH. OPTED TO MAKE LITTLE CHANGE TO PREVIOUS FORECAST...AND DIDN/T STRAY MORE THAN A FEW DEGREES FROM MET/MAV GUIDANCE CONSENSUS...RESULTING IN A RANGE FROM LOW-MID 70S IN NEB ZONES...TO MID-UPPER 70S IN KS ZONES. THESE HIGHS COULD EASILY BE OFF A BIT THOUGH BASED ON CLOUD/PRECIP TRENDS OR LACK THEREOF. LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY. BEGINNING THE MID TERM PERIOD...THE UPPER LEVEL RIDGE WHICH BROUGHT WARM TEMPERATURES AND RECORD HIGHS TO THE PLAINS WILL BEGIN TO BREAK DOWN...MAINLY DUE TO AN UPPER LEVEL TROUGH PUSHING ACROSS THE WEST COAST. AHEAD OF THIS TROUGH...A BURST OF TROUGH ENERGY IN THE FORM OF A SHORT WAVE/CLOSED LOW WILL BEGIN TO SLIDE THROUGH THE PLAINS THURSDAY NIGHT INTO FRIDAY. AS LOW PRESSURE DEVELOPS ALONG THE FRONT RANGE OF THE ROCKIES...AN INCREASED PRESSURE GRADIENT WILL HELP INCREASE EASTERLY WINDS OVERNIGHT THURSDAY. A SURGE OF MOISTURE WILL MOVE INTO THE PLAINS OVERNIGHT...AND COMBINED WITH UPPER LEVEL FORCING AND ISENTROPIC LIFT...CREATE A GOOD CHANCE FOR PRECIPITATION DURING THE OVERNIGHT HOURS ON THURSDAY...ESPECIALLY AFTER MIDNIGHT. THUNDERSTORM CHANCES CERTAINLY REMAIN POSSIBLE ESPECIALLY ACROSS THE SOUTHWEST PORTIONS OF THE FORECAST AREA BEFORE MIDNIGHT AS THE THE DRY LINE MIXES EASTWARD. CANNOT RULE OUT A STRONG TO SEVERE THUNDERSTORM ACROSS THE SOUTHEAST...DEPENDENT UPON WHERE THE DRY LINE SETS UP. AFTER MIDNIGHT AND THROUGH THE DAY ON FRIDAY...BOTH THE GFS AND THE ECMWF SOLUTION KEEP THE SURFACE LOW WELL TO THE SOUTH OF THE FORECAST AREA...THUS KEEPING MUCH OF THE MAIN INSTABILITY AXIS TO THE SOUTH. THE NAM SOLUTION IS A BIT TRICKIER AND KEEPS THE LOW SLIGHTLY FURTHER NORTH. A LARGE AREA OF WRAP AROUND MOISTURE WILL INFILTRATE THE PLAINS...FUELED BY GOOD ISENTROPIC LIFT AND UPPER LEVEL DIFFLUENCE. AT THIS TIME...GIVEN THE DIFFERENCE IN SOLUTIONS...CANNOT RULE OUT ISOLATED THUNDERSTORM CHANCES THROUGH THE DAY ON FRIDAY. THE UPPER LEVEL SHORT WAVE BEGINS TO KICK OFF TO THE EAST BY SATURDAY MORNING...WITH LINGERING POPS ACROSS THE NORTHWEST. SATURDAY LOOKS TO BE PRECIPITATION FREE...WITH PARTLY CLOUDY SKIES. AS A RESULT...DECIDED TO UP TEMPERATURES SLIGHTLY ACROSS THE REGION...WITH MID 60S EXPECTED. THE MAIN UPPER LEVEL LOW FINALLY SHIFTS NORTHWARD BY SUNDAY EVENING. HOWEVER...NUMEROUS MID LEVEL SHORT WAVES CONTINUE TO IMPACT THE PLAINS THROUGH THE LONG TERM PERIOD. SEVERAL SURFACE LOWS DEVELOP ALONG THE FRONT RANGE...PROVIDING SEVERAL CHANCES FOR RAIN SHOWERS THROUGH THE PERIOD. SPECIFICALLY...MONDAY NIGHT THROUGH TUESDAY...AN AREA OF UPPER LEVEL POSITIVE VORTICITY COMBINED WITH SURFACE LOWS WILL BRING A DECENT SHOT OF RAIN SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. INSTABILITY PARAMETERS SUGGEST MUCAPES NEAR 500 J/KG. AT THIS TIME...CANNOT RULE OUT A STRONG THUNDERSTORM OR TWO. WHILE THE WEEKEND WILL BE FAIRLY COOL...WITH HIGHS IN THE UPPER 50S TO LOWER 60S...WARMER TEMPERATURES RETURN TO THE FORECAST AREA BY TUESDAY...WITH LOWER 70S EXPECTED. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
244 PM CDT TUE APR 24 2012 .SHORT TERM...TUESDAY NIGHT THROUGH WEDNESDAY. UPPER LEVEL ANALYSIS INDICATES A STRONG UPPER LEVEL RIDGE HAS BUILT IN ACROSS THE WESTERN HALF OF THE UNITED STATES. ALONG THIS RIDGE AXIS...A SURGE OF VERY WARM 850 MB TEMPS NEAR 28 TO 30 DEGREES CELSIUS HAS CONTINUED TO TRAVERSE NORTHWARD. AT THE SURFACE...A LOW PRESSURE SYSTEM PUSHING ACROSS THE NORTHERN PLAINS HAS ALLOWED A TROUGH AXIS TO MOVE THROUGH THE CENTRAL PLAINS. STRONG BOUNDARY LAYER MIXING AND INCREASED WINDS MAINLY ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA WILL CONTINUE TO ALLOW TEMPERATURES TO CLIMB THIS AFTERNOON. SEVERAL SITES ACROSS THE ARE HAVE ALREADY HIT 90 DEGREES AND COULD EASILY INCREASE A FEW MORE DEGREES. WITH SUCH WARMING TODAY...AND SEVERAL SITES EASILY REALIZING CONVECTIVE TEMPS...WE COULD SEE SCATTERED CUMULUS DEVELOP ACROSS THE REGION THIS AFTERNOON AND MAYBE EVEN A THUNDERSTORM OR TWO. RUC AND LAPS MODELS BOTH INDICATE SOME INSTABILITY ACROSS THE REGION. FOR WEDNESDAY...THE SURFACE LOW PRESSURE SYSTEM IS EXPECTED TO SHIFT JUST NORTHEAST OF THE REGION...DRAGGING A COLD FRONT ACROSS THE FORECAST AREA. BY AFTERNOON...WINDS ARE EXPECTED TO SHIFT TO THE NORTHWEST AND EVENTUALLY NORTH. 850 TEMPERATURES LOOK TO REMAIN QUITE WARM AGAIN ON WEDNESDAY. WITH MODEL SOUNDINGS INDICATING PLENTY OF BOUNDARY LAYER MIXING...DO NOT SEE A REASON WHY WEDNESDAY WILL NOT BE AS WARM AS TODAY. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. FRONTAL BOUNDARY WHICH PUSHES SOUTH DURING THE DAY WEDNESDAY STALLS ACROSS NORTH CENTRAL KANSAS WEDNESDAY NIGHT. MODELS...ESPECIALLY THE NAM INDICATES SOME DECENT MID LEVEL FRONTOGENESIS...BETWEEN H85 AND H7...ALONG/NORTH OF THE BOUNDARY AFTER MIDNIGHT WEDNESDAY NIGHT WITH LIFT ALSO ENHANCED AS H7 SHORTWAVE TROUGH LIFTS ACROSS THE CENTRAL PLAINS. WITH INCREASING LIFT OVERNIGHT WED NIGHT...ADDED IN SOME LOW POPS. ON THURSDAY...FRONT RESIDES ACROSS CENTRAL KANSAS TO OUR SOUTH WITH SURFACE TROUGH/DRYLINE EXTENDING ALONG THE HIGH PLAINS. SREF INDICATES MUCAPES OF 3000 J/KG ALONG/SOUTH OF THE BOUNDARY WITH 500 TO 1000 OR SO J/KG AHEAD OF DRY LINE ALONG HIGH PLAINS INTO SOUTHERN NEBRASKA. EFFECTIVE SHEAR PARAMETERS ARE PROGGED BETWEEN 40 AND 50KTS. EASTERLY UPSLOPE FLOW...CONVERGENCE ALONG BOUNDARY AND NEXT WAVE LIFTING OUT IS EXPECTED TO PROVIDE SUFFICIENT FORCING FOR CONVECTIVE DEVELOPMENT AND A STRONG TO SEVERE STORM IS POSSIBLE. OUR WESTERN CWA IS OUTLOOKED IN THE DAY3 FOR SEVERE WEATHER AND THIS STILL LOOKS REASONABLE BASED ON LATEST MODEL RUNS WITH HAIL/WIND LOOKING LIKE THE PRIMARY HAZARDS. LIFT CONTINUES THURSDAY NIGHT AHEAD OF THE UPPER LOW PRESSURE SYSTEM MOVING OUT OF THE SOUTH CENTRAL ROCKIES. THE ECMWF MAINTAINS A SLOWER PROGRESSION OF THE SYSTEM THAN OTHER MODELS...AND THE SYSTEM IS PROGGED TO LIFT ACROSS KANSAS INTO NEBRASKA ON FRIDAY. IT IS SHAPING UP TO EVOLVE INTO A WIDESPREAD RAINFALL EVENT FROM THURSDAY NIGHT AND LASTING POTENTIALLY INTO FRIDAY NIGHT WHEN THE SYSTEM FILLS AND LIFTS TO THE NORTHEAST. INSTABILITY DIMINISHES SO NOT LOOKING FOR A WHOLE LOT IN THE WAY OF THUNDER BUT SOME DECENT RAINFALL AMOUNTS ARE POSSIBLE AS PRECIPITABLE WATER VALUES AVERAGE AROUND AN INCH. AS WAVE MOVES OFF EARLY IN THE WEEKEND...ANOTHER TROUGH/LOW NOSES SOUTH ONTO THE PLAINS FM THE NC ROCKIES OVER THE WEEKEND PERIOD. ALTHOUGH THE WEEKEND ITSELF DOES NOT LOOK LIKE A COMPLETE RAINOUT...INTERMITTENT CHCS FOR RAINFALL DO EXIST. THE ECMWF ADVERTISES A COLDER AIRMASS OVER THE WEEKEND COMPARED TO THE GFS WITH H85 TEMPS DROPPING TO -3 OR -4C IN OUR NORTHERN ZONES...WHILE THE GFS HAS TRENDED SLIGHTLY WARMER AROUND -2C. WILL KEEP PCPN AS RAIN SHOWERS UNTIL THESE PERIODS GET CLOSER. CONFIDENCE IS NOT HIGH REGARDING PCPN CHCS HEADING INTO NEXT WEEK BUT CANNOT ARGUE WITH ENSEMBLE FORECAST ATTM. TROUGH AXIS LOOKS TO DEPART AROUND THE TUESDAY TIME FRAME...WITH HEIGHT RISES/MODERATING TEMPS BEHIND THE SYSTEM. FOR TEMPS...AFTER HOT CONDITIONS WEDNESDAY...THURSDAY WILL BE COOLER WITH A FAIRLY SHARP TEMP GRADIENT IN MAX TEMPS N/S...WARMING NEAR THE FRONTAL ZONE. TEMPS WILL LIKELY STRUGGLE FRIDAY IN CLOUDS/PCPN...THEN THE COLD AIRMASS SETTLES IN OVER THE WEEKEND. 50S LOOK TO HOLD SAT/SUN INTO MONDAY FOR HIGHS BEFORE AIRMASS MODERATES TUESDAY. WILL NEED TO CONTINUE TO MONITOR LOW TEMPS FOR FROST/FREEZE POTENTIAL. && .PREV DISCUSSION... /ISSUED 125 PM CDT TUE APR 24 2012/ AVIATION...18Z KGRI TAF UPDATE. VFR CONDITIONS WILL CONTINUE THROUGHOUT THE TAF PERIOD. ALTHOUGH STRONGER WIND GUSTS WERE OCCURRING THIS MORNING...THE MAIN TROUGH AXIS HAS BEGUN TO SHIFT ACROSS THE REGION. AS A RESULT...WINDS HAVE DECREASED TO LIGHT AND VARIABLE ACROSS THE REGION. WITH THE WARMER TEMPERATURES THIS AFTERNOON...A FEW CUMULUS CLOUDS COULD DEVELOP ACROSS THE REGION AND POSSIBLY SPAN A SHOWER OR THUNDERSTORM. AT THIS TIME...EXPECT ANY STORMS TO BE ISOLATED IN NATURE. BY THIS EVENING...WINDS WILL BECOME LIGHT AND VARIABLE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM/AVIATION...SALTZMAN LONG TERM...FAY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1149 PM EDT WED APR 25 2012 .SYNOPSIS... HIGH PRESSURE THAT BROUGHT DRY CONDITIONS AND A FAIR AMOUNT OF SUNSHINE TO THE AREA WILL SLIDE OFF THE EAST COAST TONIGHT. LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL PASS JUST SOUTH OF NEW YORK STATE ON THURSDAY AND BRING A GOOD CHANCE FOR SHOWERS. A NORTHWEST FLOW OF CHILLY AIR WILL FOLLOW ON FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... A RIDGE OF HIGH PRESSURE WILL SLIDE OFF THE EAST COAST OVERNIGHT AS LOW PRESSURE MOVES EAST FROM IOWA AND REACH THE VICINITY OF CENTRAL OHIO BY 12Z THURSDAY. MID LEVEL CLOUDS WILL INCREASE ACROSS OUR CWA OVERNIGHT AS THIS SYSTEMS APPROACHES. MEANWHILE...LOW CLOUDS HAVE MOVED FURTHER EAST OF LAKE ONTARIO...WHICH WILL ALLOW A PERIOD OF CLEAR SKIES AND LIGHT WINDS. WHILE STILL MARGINAL...DO EXPECT FROST TO DEVELOP IN THIS NARROW WINDOW OF OPPORTUNITY EAST OF LAKE ONTARIO...WITH LOWS AROUND FREEZING. WILL GO WITH A BRIEF FROST ADVISORY FOR OSWEGO/JEFFERSON/LEWIS COUNTIES. THIS SHOULD HAVE A MODEST IMPACT...WITH BRIEF AND NEAR FREEZING TEMPERATURES IMPACTING THE SENSITIVE VEGETATION. ELSEWHERE...HIGH CLOUDS AND AN INCREASING SE FLOW WILL CAUSE TEMPERATURES TO HOLD STEADY...AND EVENTUALLY RISE IN FAR WESTERN SECTIONS TOWARD DAYBREAK. OTHERWISE...RADAR SHOWS THAT SHOWERS ASSOCIATED WITH THE APPROACHING LOW ARE QUITE CONVECTIVE IN NATURE. BOTH MODEL AND RADAR TRENDS SUGGEST A SLIGHTLY SLOWER START TIME...AS SHOWERS CONTINUE TO SLIDE TO THE SE ON A TRAJECTORY TO STAY SOUTH OF THE CWA. 00Z RUNS OF THE NAM/RGEM AND THE LATEST HRRR ARE ALL DOWNPLAYING THE POTENTIAL FOR EARLY MORNING SHOWERS...WITH A MID- TO LATE MORNING TIMING NOW APPEARING MORE LIKELY. SHOWERS WILL EVENTUALLY MOVE INTO THE REGION THURSDAY MORNING. INCREASING LOW LEVEL MOISTURE WILL FOCUS ALONG A SURFACE TROUGH THAT IS FORECAST TO EXTEND NORTH OF THE PARENT LOW. THIS WILL LEAD TO A GOOD CHANCE FOR SHOWERS...ESPECIALLY ACROSS THE NORTH COUNTRY WHERE ADDITIONAL LIFT WILL BE GENERATED BY A POTENT SHORT WAVE AND INCREASING WARM AIR ADVECTION. RIGHT NOW...IT LOOKS LIKE THE STEADIEST PCPN WILL IMPACT WESTERN NEW YORK AND THE GENESEE VALLEY LATE MORNING AND EARLY AFTERNOON...THEN SHIFT INTO THE EASTERN FINGER LAKES AND NORTH COUNTRY DURING THE AFTERNOON HOURS. WHILE THE CHANCES ARE MINIMAL...MODEST LEVELS OF ELEVATED INSTABILITY SUGGEST THERE MAY BE AN ISOLATED RUMBLE OF THUNDER ACROSS THE SOUTHERN TIER ON THURSDAY MORNING. SOUTHERLY WINDS AHEAD OF THE SURFACE TROUGH WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 50S ON THURSDAY...BEFORE COLD AIR ADVECTION SETS UP BEHIND THE TROUGH LATER IN THE AFTERNOON. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW WILL BE IN THE PROCESS OF EXITING THE AREA AT THE START OF THE PERIOD. LOW LEVEL MOISTURE SHOULD REMAIN HIGH IN WAKE OF THE SYSTEM AND THIS COMBINED WITH INCREASING LOW LEVEL COLD AIR ADVECTION WILL CONTINUE THE THREAT FOR SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO DURING THE EVENING. 850 MB TEMPERATURES DROPPING TO BETWEEN -10C AND -12C COULD VERY EASILY BRING SOME LAKE RESPONSE...ESPECIALLY EAST OF LAKE ONTARIO AND THE WESTERN SOUTHERN TIER. BOUNDARY LAYER SHOULD GET COLDER ENOUGH TO SEE A CHANGE OVER TO ALL SNOW OVER THE HIGHER ELEVATIONS. MINOR ACCUMULATIONS IN THE 1 TO 2 INCH RANGE ARE POSSIBLE. SNOW/RAIN SHOWERS WILL LIKELY LINGER FRIDAY MORNING ACROSS EASTERN SECTIONS...BUT WITH SURFACE RIDGING AND ASSOCIATED DRIER AIR BUILDING INTO THE REGION WE WILL SEE AN IMPROVING TREND FOR FRIDAY. STILL PLENTY OF COLD AIR ALOFT WITH 850 MB TEMPERATURES BETWEEN -6C TO -10C...YIELDING DAYTIME HIGHS FRIDAY ONLY IN THE 40S. TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING WILL BE A CONCERN. CLEAR SKIES AND LIGHT WINDS WILL BRING WIDESPREAD FREEZE/FROST CONCERNS. MODEL CONSENSUS CONTINUES TO KEEP THE NORTHERN EDGE OF MOISTURE ALONG AND NORTH OF THE APPROACH WARM FRONT LIFTING UP ACROSS THE OHIO VALLEY TO THE SOUTH OF THE AREA FOR SATURDAY. THE GFS IS THE FARTHER NORTH OF THE SOLUTIONS AND JUST NUDGES THE SOUTHERN TIER WITH SOME VERY MINOR QPF...BUT THE NAM/GEM/ECMWF/SREF SOLUTIONS ALL KEEP HOLD THE PRECIPITATION SOUTH OF THE REGION. AT THIS POINT WILL STAY CLOSE TO MODEL CONSENSUS AND KEEP THE AREA DRY FOR SATURDAY. TEMPERATURES AGAIN SATURDAY NIGHT WILL BE A CONCERN...WITH THE POTENTIAL FOR MORE FREEZE/FROST CONCERNS AS THE HIGH REMAINS PARKED OVER THE REGION. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... LATEST MEDIUM RANGE MODELS AND ENSEMBLES CONTINUING TO SUGGEST THIS PERIOD WILL BE COOL WITH MAINLY QUIET WEATHER. WESTERN AND CENTRAL NEW YORK WILL REMAIN IN A NORTHWESTERLY FLOW REGIME BETWEEN SLOWLY DEPARTING UPPER LOW SPINNING ACROSS EASTERN CANADA AND A SLOWLY PROGRESSIVE RIDGE ACROSS CENTRAL CANADA. AT THE SURFACE...A SPRAWLING AREA OF HIGH PRESSURE WILL SLOWLY BUILD TO THE SOUTHEAST FROM CENTRAL CANADA...SETTLING OVER WESTERN AND CENTRAL NEW YORK DURING THE FIRST HALF OFF THE PERIOD. WARM FRONTAL PRECIPITATION LOOKS TO REMAIN WELL TO THE SOUTH OFF THE AREA DURING THE WEEKEND. THE HIGH REMAINS THE DOMINANT FEATURE TUESDAY...ALTHOUGH SHIFTING EAST OF THE REGION. THIS WILL ALLOW WARM AIR ADVECTION TO SET UP AHEAD OF A FAST MOVING PACIFIC SHORTWAVE WEDNESDAY. WEDNESDAY LOOKS TO HAVE THE BEST THREAT FOR PRECIPITATION AS THIS WAVE WORKS ACROSS THE REGION. BASICALLY...WITH THE CONTINENTAL POLAR AIRMASS REMAINING FIRMLY IN PLACE IN THE SUNDAY THROUGH TUESDAY TIME FRAME. THERE SHOULD BE PLENTY OF SUNSHINE WITH A GRADUAL WARMING TREND. WEDNESDAY LIKELY TO BE THE MILDEST DAY AS WARMER AIR CONTINUES TO SPREAD INTO THE REGION IN A STRENGTHENING RETURN FLOW. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... CONFIDENT IN VFR CONDITIONS THROUGH THIS EVENING...AS APPROACHING CLOUDS SHOULD BE IN THE MID AND UPPER LEVELS. THE COMBINATION OF LOW PRESSURE AND A TROF IN THE MID-LEVELS WILL CROSS FROM WEST TO EAST THURSDAY MORNING INTO THURSDAY AFTERNOON. WHILE SHOWERS MAY SPREAD OUT AHEAD OF THIS...MAINLY VFR CONDITIONS ARE LIKELY AHEAD OF THE WIND SHIFT...WITH CIGS/VSBY LIKELY TO REMAIN UP. AFTER THE WIND SHIFT...EXPECT CIGS TO LOWER...RESULTING IN FAIRLY WIDESPREAD MVFR TO POSSIBLY IFR CONDITIONS ACROSS WESTERN NEW YORK. THE RUC AND 00Z NAM DO SHOW A MODEST LOW LEVEL JET TO 35 KNOTS. AT BUF/IAG THIS SHOULD BE IN QUITE A DIFFERENT DIRECTION FROM SURFACE WINDS...SO WILL CARRY A BRIEF PERIOD OF LLWS. ITS ALSO MARGINAL AT JHW...BUT SEE A BETTER CHANCE FOR MIXING THERE...WITH BETTER ALIGNED WINDS LIKELY TO RESULT IN SOME GUSTS TO THE SURFACE MORE SO THAN SHEAR. OUTLOOK... FRIDAY...MAINLY VFR WITH CHANCE RAIN SATURDAY...MAINLY VFR. SUNDAY AND MONDAY...VFR. && .MARINE... LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL TRACK SOUTH OF NEW YORK STATE THURSDAY...THEN SETTLE OFF THE EAST COAST THURSDAY NIGHT. A BRISK WEST TO NORTHWEST FLOW IN THE WAKE OF THIS LOW WILL LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS THURSDAY NIGHT AND FRIDAY. HIGH PRESSURE WILL BRING QUIETER CONDITIONS SATURDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FROST ADVISORY UNTIL 7 AM EDT THURSDAY FOR NYZ006>008. MARINE...NONE. && $$ SYNOPSIS...TJP NEAR TERM...APFFEL/TJP SHORT TERM...TMA LONG TERM...TMA AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
954 PM EDT WED APR 25 2012 .SYNOPSIS... HIGH PRESSURE THAT BROUGHT DRY CONDITIONS AND A FAIR AMOUNT OF SUNSHINE TO THE AREA WILL SLIDE OFF THE EAST COAST TONIGHT. LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL PASS JUST SOUTH OF NEW YORK STATE ON THURSDAY AND BRING A GOOD CHANCE FOR SHOWERS. A NORTHWEST FLOW OF CHILLY AIR WILL FOLLOW ON FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... A RIDGE OF HIGH PRESSURE WILL SLIDE OFF THE EAST COAST OVERNIGHT AS LOW PRESSURE MOVES EAST FROM IOWA AND REACH THE VICINITY OF CENTRAL OHIO BY 12Z THURSDAY. MID LEVEL CLOUDS WILL INCREASE ACROSS OUR CWA OVERNIGHT AS THIS SYSTEMS APPROACHES. MEANWHILE...LOW CLOUDS HAVE MOVED FURTHER EAST OF LAKE ONTARIO...WHICH WILL ALLOW A PERIOD OF CLEAR SKIES AND LIGHT WINDS. WHILE STILL MARGINAL...DO EXPECT FROST TO DEVELOP IN THIS NARROW WINDOW OF OPPORTUNITY EAST OF LAKE ONTARIO...WITH LOWS AROUND FREEZING. WILL GO WITH A BRIEF FROST ADVISORY FOR OSWEGO/JEFFERSON/LEWIS COUNTIES. THIS SHOULD HAVE A MODEST IMPACT...WITH BRIEF AND NEAR FREEZING TEMPERATURES IMPACTING THE SENSITIVE VEGETATION. ELSEWHERE...HIGH CLOUDS AND AN INCREASING SE FLOW WILL CAUSE TEMPERATURES TO HOLD STEADY...AND EVENTUALLY RISE IN FAR WESTERN SECTIONS TOWARD DAYBREAK. OTHERWISE...RADAR SHOWS THAT SHOWERS ASSOCIATED WITH THE APPROACHING LOW ARE QUITE CONVECTIVE IN NATURE. THE MAJORITY OF MODELS (12Z RGEM/HRRR/18Z GFS) KEEP THIS JUST SOUTHWEST OF THE CWA THROUGH 12Z THURSDAY...HOWEVER SOME MODELS (18Z NAM) DO CLIP WESTERN PORTIONS OF THE SOUTHERN TIER. LOOKING AT THE BUFKIT FROM THE NAM...MOST OF THE LIFT APPEARS TO BE FROM ELEVATED INSTABILITY AS UPSTREAM SHOWERS ADVECT INTO THE REGION. WITH RADAR TRENDS SUGGESTING SHOWERS WILL CONTINUE TO SLIDE TO THE SOUTHEAST...HAVE PUSHED BACK THE TIMING OF SHOWERS TO AROUND DAYBREAK ON THURSDAY. EXPECT SHOWERS WILL MOVE INTO THE REGION THURSDAY MORNING. INCREASING LOW LEVEL MOISTURE WILL FOCUS ALONG A SURFACE TROUGH THAT IS FORECAST TO EXTEND NORTH OF THE PARENT LOW. THIS WILL LEAD TO A GOOD CHANCE FOR SHOWERS...ESPECIALLY ACROSS THE NORTH COUNTRY WHERE ADDITIONAL LIFT WILL BE GENERATED BY A POTENT SHORT WAVE AND INCREASING WARM AIR ADVECTION. RIGHT NOW...IT LOOKS LIKE THE STEADIEST PCPN WILL IMPACT WESTERN NEW YORK AND THE GENESEE VALLEY LATE MORNING AND EARLY AFTERNOON...THEN SHIFT INTO THE EASTERN FINGER LAKES AND NORTH COUNTRY DURING THE AFTERNOON HOURS. WHILE THE CHANCES ARE MINIMAL...MODEST LEVELS OF ELEVATED INSTABILITY SUGGEST THERE MAY BE AN ISOLATED RUMBLE OF THUNDER ACROSS THE SOUTHERN TIER ON THURSDAY MORNING. SOUTHERLY WINDS AHEAD OF THE SURFACE TROUGH WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 50S ON THURSDAY...BEFORE COLD AIR ADVECTION SETS UP BEHIND THE TROUGH LATER IN THE AFTERNOON. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW WILL BE IN THE PROCESS OF EXITING THE AREA AT THE START OF THE PERIOD. LOW LEVEL MOISTURE SHOULD REMAIN HIGH IN WAKE OF THE SYSTEM AND THIS COMBINED WITH INCREASING LOW LEVEL COLD AIR ADVECTION WILL CONTINUE THE THREAT FOR SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO DURING THE EVENING. 850 MB TEMPERATURES DROPPING TO BETWEEN -10C AND -12C COULD VERY EASILY BRING SOME LAKE RESPONSE...ESPECIALLY EAST OF LAKE ONTARIO AND THE WESTERN SOUTHERN TIER. BOUNDARY LAYER SHOULD GET COLDER ENOUGH TO SEE A CHANGE OVER TO ALL SNOW OVER THE HIGHER ELEVATIONS. MINOR ACCUMULATIONS IN THE 1 TO 2 INCH RANGE ARE POSSIBLE. SNOW/RAIN SHOWERS WILL LIKELY LINGER FRIDAY MORNING ACROSS EASTERN SECTIONS...BUT WITH SURFACE RIDGING AND ASSOCIATED DRIER AIR BUILDING INTO THE REGION WE WILL SEE AN IMPROVING TREND FOR FRIDAY. STILL PLENTY OF COLD AIR ALOFT WITH 850 MB TEMPERATURES BETWEEN -6C TO -10C...YIELDING DAYTIME HIGHS FRIDAY ONLY IN THE 40S. TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING WILL BE A CONCERN. CLEAR SKIES AND LIGHT WINDS WILL BRING WIDESPREAD FREEZE/FROST CONCERNS. MODEL CONSENSUS CONTINUES TO KEEP THE NORTHERN EDGE OF MOISTURE ALONG AND NORTH OF THE APPROACH WARM FRONT LIFTING UP ACROSS THE OHIO VALLEY TO THE SOUTH OF THE AREA FOR SATURDAY. THE GFS IS THE FARTHER NORTH OF THE SOLUTIONS AND JUST NUDGES THE SOUTHERN TIER WITH SOME VERY MINOR QPF...BUT THE NAM/GEM/ECMWF/SREF SOLUTIONS ALL KEEP HOLD THE PRECIPITATION SOUTH OF THE REGION. AT THIS POINT WILL STAY CLOSE TO MODEL CONSENSUS AND KEEP THE AREA DRY FOR SATURDAY. TEMPERATURES AGAIN SATURDAY NIGHT WILL BE A CONCERN...WITH THE POTENTIAL FOR MORE FREEZE/FROST CONCERNS AS THE HIGH REMAINS PARKED OVER THE REGION. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... LATEST MEDIUM RANGE MODELS AND ENSEMBLES CONTINUING TO SUGGEST THIS PERIOD WILL BE COOL WITH MAINLY QUIET WEATHER. WESTERN AND CENTRAL NEW YORK WILL REMAIN IN A NORTHWESTERLY FLOW REGIME BETWEEN SLOWLY DEPARTING UPPER LOW SPINNING ACROSS EASTERN CANADA AND A SLOWLY PROGRESSIVE RIDGE ACROSS CENTRAL CANADA. AT THE SURFACE...A SPRAWLING AREA OF HIGH PRESSURE WILL SLOWLY BUILD TO THE SOUTHEAST FROM CENTRAL CANADA...SETTLING OVER WESTERN AND CENTRAL NEW YORK DURING THE FIRST HALF OFF THE PERIOD. WARM FRONTAL PRECIPITATION LOOKS TO REMAIN WELL TO THE SOUTH OFF THE AREA DURING THE WEEKEND. THE HIGH REMAINS THE DOMINANT FEATURE TUESDAY...ALTHOUGH SHIFTING EAST OF THE REGION. THIS WILL ALLOW WARM AIR ADVECTION TO SET UP AHEAD OF A FAST MOVING PACIFIC SHORTWAVE WEDNESDAY. WEDNESDAY LOOKS TO HAVE THE BEST THREAT FOR PRECIPITATION AS THIS WAVE WORKS ACROSS THE REGION. BASICALLY...WITH THE CONTINENTAL POLAR AIRMASS REMAINING FIRMLY IN PLACE IN THE SUNDAY THROUGH TUESDAY TIME FRAME. THERE SHOULD BE PLENTY OF SUNSHINE WITH A GRADUAL WARMING TREND. WEDNESDAY LIKELY TO BE THE MILDEST DAY AS WARMER AIR CONTINUES TO SPREAD INTO THE REGION IN A STRENGTHENING RETURN FLOW. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... CONFIDENT IN VFR CONDITIONS THROUGH THIS EVENING...AS APPROACHING CLOUDS SHOULD BE IN THE MID AND UPPER LEVELS. THE COMBINATION OF LOW PRESSURE AND A TROF IN THE MID-LEVELS WILL CROSS FROM WEST TO EAST THURSDAY MORNING INTO THURSDAY AFTERNOON. WHILE SHOWERS MAY SPREAD OUT AHEAD OF THIS...MAINLY VFR CONDITIONS ARE LIKELY AHEAD OF THE WIND SHIFT...WITH CIGS/VSBY LIKELY TO REMAIN UP. AFTER THE WIND SHIFT...EXPECT CIGS TO LOWER...RESULTING IN FAIRLY WIDESPREAD MVFR TO POSSIBLY IFR CONDITIONS ACROSS WESTERN NEW YORK. ALSO...THE RUC AND TO A LESSER EXTENT NAM/GFS...BRING A MODEST LOW LEVEL JET OUT AHEAD OF THE LOW. CURRENT FORECASTS ARE IN THE 30 TO 35 KT BALLPARK...WHICH IS GENERALLY SHY OF LLWS CRITERIA...BUT CLOSE. FOR NOW...LEAVE LLWS OUT OF TAFS...BUT WILL MONITOR AND CONSIDER ADDING TO SOME TAFS SHEAR IF THERE IS INDICATION THAT THIS LOW LEVEL JET WILL BE STRONGER. OUTLOOK... FRIDAY...MAINLY VFR WITH CHANCE RAIN SATURDAY...MAINLY VFR. SUNDAY AND MONDAY...VFR. && .MARINE... LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL TRACK SOUTH OF NEW YORK STATE THURSDAY...THEN SETTLE OFF THE EAST COAST THURSDAY NIGHT. A BRISK WEST TO NORTHWEST FLOW IN THE WAKE OF THIS LOW WILL LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS THURSDAY NIGHT AND FRIDAY. HIGH PRESSURE WILL BRING QUIETER CONDITIONS SATURDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FROST ADVISORY FROM 1 AM TO 7 AM EDT THURSDAY FOR NYZ006>008. MARINE...NONE. && $$ SYNOPSIS...TJP NEAR TERM...APFFEL/TJP SHORT TERM...TMA LONG TERM...TMA AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
737 PM EDT WED APR 25 2012 .SYNOPSIS... HIGH PRESSURE THAT BROUGHT DRY CONDITIONS AND A FAIR AMOUNT OF SUNSHINE TO THE AREA WILL SLIDE OFF THE EAST COAST TONIGHT. LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL PASS JUST SOUTH OF NEW YORK STATE ON THURSDAY AND BRING A GOOD CHANCE FOR SHOWERS. A NORTHWEST FLOW OF CHILLY AIR WILL FOLLOW ON FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... A RIDGE OF HIGH PRESSURE WILL SLIDE OFF THE EAST COAST OVERNIGHT AS LOW PRESSURE MOVES EAST FROM IOWA AND REACH THE VICINITY OF CENTRAL OHIO BY 12Z THURSDAY. MID LEVEL CLOUDS WILL INCREASE ACROSS OUR CWA OVERNIGHT AS THIS SYSTEMS APPROACHES. THE INCREASING CLOUD COVER WILL KEEP OVERNIGHT LOWS ABOVE FREEZING ACROSS MOST AREAS WEST OF THE NORTH COUNTRY. EAST OF LAKE ONTARIO...TEMPERATURES MAY DIP TO FREEZING FOR A FEW HOURS BEFORE THE CLOUDS MOVE IN...THEN SHOW A MODERATING TREND BEFORE DAYBREAK. EXPECT THE INCREASING CLOUD COVER AND WET/WARMER GROUND TO PRECLUDE THE DEVELOPMENT OF A WIDESPREAD FROST/FREEZE. BUT...THIS SITUATION WILL HAVE TO BE MONITORED CLOSELY THIS EVENING. OTHERWISE...RADAR SHOWS THAT SHOWERS FORMING AHEAD OF THE WARM FRONT ARE QUITE CONVECTIVE IN NATURE. THE MAJORITY OF MODELS (12Z RGEM/HRRR/18Z GFS) SLIDE KEEP THIS JUST SOUTHWEST OF THE CWA THROUGH 12Z THURSDAY...HOWEVER SOME MODELS (18Z NAM) DO CLIP WESTERN PORTIONS OF THE SOUTHERN TIER. THE 18Z NAM DOES FORECAST SHOWERS TO REACH CHAUTAUQUA COUNTY LATE TONIGHT...WITH MOST OF THE LIFT COMING FROM ELEVATED INSTABILITY AS UPSTREAM SHOWERS ADVECT INTO THE REGION. WILL MONITOR UPSTREAM...SINCE IF THE NAM IS WRONG IN ITS FORECAST OF SHOWERS UPSTREAM...THEN WESTERN NEW YORK WILL LIKELY REMAIN DRY THROUGH DAYBREAK. EITHER WAY...STEADIER SHOWERS WILL MOVE INTO THE REGION ON THURSDAY MORNING. INCREASING LOW LEVEL MOISTURE WILL FOCUS ALONG A SURFACE TROUGH THAT IS FORECAST TO EXTEND NORTH OF THE PARENT LOW. THIS WILL LEAD TO A GOOD CHANCE FOR SHOWERS...ESPECIALLY ACROSS THE NORTH COUNTRY WHERE ADDITIONAL LIFT WILL BE GENERATED BY A POTENT SHORT WAVE THAT WILL BE DROPPING SOUTH TOWARD NORTHERN NEW YORK STATE. RIGHT NOW...IT LOOKS LIKE THE STEADIEST PCPN WILL IMPACT WESTERN NEW YORK AND THE GENESEE VALLEY DURING THE MORNING...THEN SHIFT INTO THE EASTERN FINGER LAKES AND NORTH COUNTRY DURING THE AFTERNOON. SOUTHERLY WINDS AHEAD OF THE SURFACE TROUGH WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 50S ON THURSDAY...BEFORE COLD AIR ADVECTION SETS UP BEHIND THE TROUGH LATER IN THE AFTERNOON. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW WILL BE IN THE PROCESS OF EXITING THE AREA AT THE START OF THE PERIOD. LOW LEVEL MOISTURE SHOULD REMAIN HIGH IN WAKE OF THE SYSTEM AND THIS COMBINED WITH INCREASING LOW LEVEL COLD AIR ADVECTION WILL CONTINUE THE THREAT FOR SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO DURING THE EVENING. 850 MB TEMPERATURES DROPPING TO BETWEEN -10C AND -12C COULD VERY EASILY BRING SOME LAKE RESPONSE...ESPECIALLY EAST OF LAKE ONTARIO AND THE WESTERN SOUTHERN TIER. BOUNDARY LAYER SHOULD GET COLDER ENOUGH TO SEE A CHANGE OVER TO ALL SNOW OVER THE HIGHER ELEVATIONS. MINOR ACCUMULATIONS IN THE 1 TO 2 INCH RANGE ARE POSSIBLE. SNOW/RAIN SHOWERS WILL LIKELY LINGER FRIDAY MORNING ACROSS EASTERN SECTIONS...BUT WITH SURFACE RIDGING AND ASSOCIATED DRIER AIR BUILDING INTO THE REGION WE WILL SEE AN IMPROVING TREND FOR FRIDAY. STILL PLENTY OF COLD AIR ALOFT WITH 850 MB TEMPERATURES BETWEEN -6C TO -10C...YIELDING DAYTIME HIGHS FRIDAY ONLY IN THE 40S. TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING WILL BE A CONCERN. CLEAR SKIES AND LIGHT WINDS WILL BRING WIDESPREAD FREEZE/FROST CONCERNS. MODEL CONSENSUS CONTINUES TO KEEP THE NORTHERN EDGE OF MOISTURE ALONG AND NORTH OF THE APPROACH WARM FRONT LIFTING UP ACROSS THE OHIO VALLEY TO THE SOUTH OF THE AREA FOR SATURDAY. THE GFS IS THE FARTHER NORTH OF THE SOLUTIONS AND JUST NUDGES THE SOUTHERN TIER WITH SOME VERY MINOR QPF...BUT THE NAM/GEM/ECMWF/SREF SOLUTIONS ALL KEEP HOLD THE PRECIPITATION SOUTH OF THE REGION. AT THIS POINT WILL STAY CLOSE TO MODEL CONSENSUS AND KEEP THE AREA DRY FOR SATURDAY. TEMPERATURES AGAIN SATURDAY NIGHT WILL BE A CONCERN...WITH THE POTENTIAL FOR MORE FREEZE/FROST CONCERNS AS THE HIGH REMAINS PARKED OVER THE REGION. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... LATEST MEDIUM RANGE MODELS AND ENSEMBLES CONTINUING TO SUGGEST THIS PERIOD WILL BE COOL WITH MAINLY QUIET WEATHER. WESTERN AND CENTRAL NEW YORK WILL REMAIN IN A NORTHWESTERLY FLOW REGIME BETWEEN SLOWLY DEPARTING UPPER LOW SPINNING ACROSS EASTERN CANADA AND A SLOWLY PROGRESSIVE RIDGE ACROSS CENTRAL CANADA. AT THE SURFACE...A SPRAWLING AREA OF HIGH PRESSURE WILL SLOWLY BUILD TO THE SOUTHEAST FROM CENTRAL CANADA...SETTLING OVER WESTERN AND CENTRAL NEW YORK DURING THE FIRST HALF OFF THE PERIOD. WARM FRONTAL PRECIPITATION LOOKS TO REMAIN WELL TO THE SOUTH OFF THE AREA DURING THE WEEKEND. THE HIGH REMAINS THE DOMINANT FEATURE TUESDAY...ALTHOUGH SHIFTING EAST OF THE REGION. THIS WILL ALLOW WARM AIR ADVECTION TO SET UP AHEAD OF A FAST MOVING PACIFIC SHORTWAVE WEDNESDAY. WEDNESDAY LOOKS TO HAVE THE BEST THREAT FOR PRECIPITATION AS THIS WAVE WORKS ACROSS THE REGION. BASICALLY...WITH THE CONTINENTAL POLAR AIRMASS REMAINING FIRMLY IN PLACE IN THE SUNDAY THROUGH TUESDAY TIME FRAME. THERE SHOULD BE PLENTY OF SUNSHINE WITH A GRADUAL WARMING TREND. WEDNESDAY LIKELY TO BE THE MILDEST DAY AS WARMER AIR CONTINUES TO SPREAD INTO THE REGION IN A STRENGTHENING RETURN FLOW. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... CONFIDENT IN VFR CONDITIONS THROUGH THIS EVENING...AS APPROACHING CLOUDS SHOULD BE IN THE MID AND UPPER LEVELS. THE COMBINATION OF LOW PRESSURE AND A TROF IN THE MID-LEVELS WILL CROSS FROM WEST TO EAST THURSDAY MORNING INTO THURSDAY AFTERNOON. WHILE SHOWERS MAY SPREAD OUT AHEAD OF THIS...MAINLY VFR CONDITIONS ARE LIKELY AHEAD OF THE WIND SHIFT...WITH CIGS/VSBY LIKELY TO REMAIN UP. AFTER THE WIND SHIFT...EXPECT CIGS TO LOWER...RESULTING IN FAIRLY WIDESPREAD MVFR TO POSSIBLY IFR CONDITIONS ACROSS WESTERN NEW YORK. ALSO...THE RUC AND TO A LESSER EXTENT NAM/GFS...BRING A MODEST LOW LEVEL JET OUT AHEAD OF THE LOW. CURRENT FORECASTS ARE IN THE 30 TO 35 KT BALLPARK...WHICH IS GENERALLY SHY OF LLWS CRITERIA...BUT CLOSE. FOR NOW...LEAVE LLWS OUT OF TAFS...BUT WILL MONITOR AND CONSIDER ADDING TO SOME TAFS SHEAR IF THERE IS INDICATION THAT THIS LOW LEVEL JET WILL BE STRONGER. OUTLOOK... FRIDAY...MAINLY VFR WITH CHANCE RAIN SATURDAY...MAINLY VFR. SUNDAY AND MONDAY...VFR. && .MARINE... WIND AND WAVES ON THE LAKES WILL CONTINUE TO SUBSIDE THIS AFTERNOON AND EVENING AS THE PRESSURE GRADIENT WEAKENS. THEREFORE...ALL SMALL CRAFT ADVISORIES WILL BE ALLOWED TO EXPIRE. MEANWHILE...LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL TRACK SOUTH OF NEW YORK STATE THURSDAY...THEN SETTLE OFF THE EAST COAST THURSDAY NIGHT. A BRISK WEST TO NORTHWEST FLOW IN THE WAKE OF THIS LOW WILL LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS THURSDAY NIGHT AND FRIDAY. HIGH PRESSURE WILL BRING QUIETER CONDITIONS SATURDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...TJP NEAR TERM...APFFEL/TJP SHORT TERM...TMA LONG TERM...TMA AVIATION...APFFEL MARINE...TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 AM EDT TUE APR 24 2012 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL DIVE SOUTHEASTWARD ACROSS OUR REGION THIS AFTERNOON AND EVENING. WEAK HIGH PRESSURE WILL FOLLOW FOR LATER TONIGHT THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10 PM MONDAY... DEEP LOW PRESSURE OVER THE NORTHEAST US IS EXPECTED TO BECOME VERTICALLY STACKED BY DAYBREAK. SCATTERED SHOWERS SEEN EARLIER THIS EVENING HAVE LONG ENDED AND SOME BREAKS HAVE STARTED TO DEVELOP IN THE RATHER EXTENSIVE CLOUD SHIELD AS CENTRAL NC WILL SEE A PERIOD OF SUBSIDENCE OVERNIGHT BETWEEN THE NEXT SUBSTANTIAL VORT MAX PIVOTS ACROSS THE AREA. THIS SHOULD RESULT IN A CONTINUED DECREASE IN CLOUDS WITH MOSTLY CLEAR SKIES EXPECTED BY DAYBREAK. WINDS APPEAR AS IF THEY WILL REMAIN UP OVERNIGHT WITH LATEST SFC ANALYSIS AND RUC FORECAST MSL PRESSURE CONTINUING TO DEPICT A GOOD 4 TO 5 MB PRESSURE GRADIENT OVER THE AREA TONIGHT...WHICH SHOULD KEEP WINDS STIRRING BETWEEN 4 TO 6 KTS. THIS MIXING COUPLED WITH GRADUAL CLEARING SHOULD RESULT IN A SLOW TEMPERATURE FALL OVERNIGHT WITH TEMPERATURES MOSTLY IN THE UPPER 30S TO LOWER 40S. A FEW OUTLYING/SHELTERED AREAS COULD FALL INTO THE MID 30S(34-35)FOR A BRIEF...ONE TO TWO HOUR WINDOW JUST BEFORE DAYBREAK...WHICH COULD RESULT IN SOME VERY PATCHY FROST AT BEST. GIVEN THE UNFAVORABLE CONDITIONS AND THE EXPECTED LIMITED NATURE IN FROST DEVELOPMENT...WILL CONTINUE TO MENTION PATCHY FROST IN HWO ONLY...WITH NO PLANS ON ISSUING AN ADVISORY. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 310 PM MONDAY... ANOTHER VORT MAXIMUM IN NW FLOW BEHIND DEPARTING UPPER LEVEL LOW WILL APPROACH OUR REGION TUESDAY MORNING AND AFFECT OUR AREA TUESDAY AFTERNOON-EVENING. MODEL GUIDANCE HAS COME INTO BETTER CONSENSUS AS FAR AS PATH AND TIMING. ASSOCIATED MID LEVEL COOL POOL WITH THIS FEATURE WILL YIELD MID LEVEL LAPSE RATES 7-8 DEGREE C/KM. IF SHOWERS OBTAIN SUFFICIENT DEPTH...MAY SEE A FEW LIGHTNING STRIKES AND SMALL HAIL WITH THE STRONGER CORES. ALSO INVERTED VEE SOUNDINGS SUGGEST POTENTIAL FOR GUSTY WINDS...THOUGH WIND PROFILE THROUGH THE COLUMN (BELOW 12K FT) AOB 25KTS. THUS GUSTS SHOULD BE BELOW SEVERE CRITERIA. SHOULD SEE DECENT DISPLAY OF SUN THROUGH THE THE MORNING AND POSSIBLY EARLY AFTERNOON HOURS BEFORE CLOUDS INCREASE THICKEN. THICKNESSES TUESDAY RECOVER ABOUT 15M FROM TODAY`S UNSEASONABLY LOW VALUES (ABOUT 40M BELOW NORMAL). STILL...MAX TEMPS WILL AVERAGE 10 DEGREES BE NORMAL IN THE MID-UPPER 60S. IF CLOUDS DEVELOP SOONER THAN EXPECTED....MAX TEMPS MAY END UP BEING 3-4 DEGREES COOLER...ESPECIALLY SW HALF. ANOTHER BREEZY DAY EXPECTED TUESDAY DUE TO DEEP LOW OVER THE EASTERN LAKES/SOUTHERN NEW ENGLAND AND HIGH PRESSURE OVER THE LOWER MS VALLEY. EXPECT WLY WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH. WINDS WILL SUBSIDE A BIT IN THE AFTERNOON AS CLOUD COVERAGE INCREASES/THICKENS. TUESDAY NIGHT...VORT MAX WILL SLIDE JUST SW OF OUR REGION IN THE EVENING...ITS INFLUENCE WANING BY MIDNIGHT. THIS SHOULD LEAD TO DECREASING CLOUD COVERAGE. MIN TEMPS UPPER 30S NE TO THE LOW-MID 40S WEST AND SOUTH. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 300 PM MONDAY... WITH SURFACE HIGH PRESSURE CENTERED OVER FL 12Z WEDNESDAY AND RIDGING INTO NC...EXPECT WEDNESDAY TO REMAIN DRY FOR THE MOST PART WITH SOME SHOWERS APPROACHING FROM THE WEST WEDNESDAY AND INTO WEDNESDAY NIGHT. HIGH TEMPS WEDNESDAY RANGING FROM THE UPPER 60S N TO MID 70S SW. MODEL SOLUTIONS ARE STILL NOT IN VERY GOOD AGREEMENT WITH THE POTENTIAL SHORT WAVES IMPACTING NC OVER THE REMAINDER OF THE FORECAST PERIOD. THAT BEING SAID...BOTH THE GFS AND ECMWF INDICATE THE SHORT WAVE MOVING OVER NC THURSDAY NIGHT SO THERE IS CONFIDENCE THAT AT LEAST THE NORTHERN HALF OF THE AREA WILL GET SOME PRECIP. HAVE CONTINUED CHANCE POPS THURSDAY AFTERNOON AND THURSDAY NIGHT WITH THE CHANCE FOR SOME ISOLATED THUNDER THURSDAY EVENING. LOWS WEDNESDAY NIGHT AND THURSDAY NIGHT IN THE MID TO UPPER 50S...WITH HIGHS THURSDAY IN THE UPPER 70S NORTH TO LOW 80S SOUTH. EXPECT WINDS TO BE 10-15 KTS THURSDAY AFTERNOON. AS STATED IN THE PREVIOUS DISCUSSION...FRIDAYS FORECAST WILL BE DETERMINED BY HOW FAR SOUTH THE EAST WEST FRONT TRAILING AN OFFSHORE SURFACE LOW WILL PUSH... AND IF HIGH PRESSURE WILL BE ABLE TO SPILL OVER THE MID ATLANTIC MOUNTAINS AND SOUTH... OR REMAIN MORE CONFINED WEST OF THE APPALACHIANS. ALTHOUGH CONFIDENCE IS NOT HIGH...HAVE LEANED MORE TOWARD THE GFS SOLUTIONS FOR FRIDAY AND FRIDAY NIGHT WHICH DEPICT A SFC LOW DEVELOPING OVER NC FRIDAY NIGHT. AS SUCH...HAVE LEFT THE CHANCE FOR PRECIP ACROSS THE NE WITH SLIGHT CHANCE ELSEWHERE. HIGHS FRIDAY IN THE LOW TO MID 70S AND LOWS IN THE UPPER 40S TO MID 50S...HOWEVER THIS IS DEPENDENT ON WHETHER OR NOT PRECIP DOES IN FACT DEVELOP AND ARE SUBJECT TO CHANGE. HIGH PRESSURE SHOULD BUILD IN FOR SATURDAY AND SUNDAY BEFORE THE NEXT SYSTEM APPROACHES FROM THE NW SUNDAY NIGHT. HAVE KEPT THE FORECAST DRY THROUGH MONDAY. GIVEN THE DIFFERENCES IN MODEL SOLUTIONS REGARDING THE TIMING OF THE NEXT SYSTEM PRECIP IS POSSIBLE SUNDAY NIGHT INTO MONDAY...HOWEVER CONFIDENCE IS TOO LOW ON WHEN IT WILL OCCUR THAT HAVE LEFT POPS JUST UNDER SLIGHT CHANCE. HIGHS SATURDAY IN THE UPPER 60S TO MID 70S NE TO SW. WARMER SUNDAY AND MONDAY WITH HIGHS IN THE 70S. LOWS SATURDAY AND SUNDAY NIGHT NEAR 50 NORTH AND MID 50S SOUTH. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 135 AM TUESDAY... CLEARING SKIES AND LIGHT SOUTHWEST WINDS WILL RULE THROUGH 12-14Z...BEFORE RESIDUALLY STRONG CYCLONIC FLOW AROUND AN OCCLUDING LOW PRESSURE SYSTEM NEAR LAKE ERIE MIXES THROUGH THE BOUNDARY LAYER WITH DAYTIME HEATING AND YIELDS STRONG WESTERLY SURFACE WINDS -- SUSTAINED 15-20 KTS WITH GUSTS OF 20-25 KTS -- FOR THE REMAINDER OF THE DAY. INITIALLY CLEAR SKIES WILL FILL WITH BROKEN HIGH-BASED CUMULUS BETWEEN 7-8 THOUSAND FEET DURING THE AFTERNOON OWING TO THE APPROACH OF A COMPACT MID-UPPER LEVEL DISTURBANCE IN NORTHWESTERLY FLOW ALOFT; AND SOME OF THESE CUMULUS WILL DEEPEN SUFFICIENTLY TO PRODUCE WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITH GUSTY SURFACE WINDS OF UP TO 40-45 KTS BETWEEN 22Z-05Z. HAVE ACCORDINGLY INCLUDED VICINITY SHOWERS IN ALL TAFS TO ACCOUNT FOR THIS PROBABILITY. SURFACE WINDS WILL DIMINISH WITH LOSS OF HEATING AND RESULTANT BOUNDARY LAYER MIXING DURING THE EVENING...WITH JUST SCATTERED MID-HIGH LEVEL CLOUDS AT WORST EXPECTED FOR THE REMAINDER OF THE NIGHT. OUTLOOK: BRIEF EPISODES OF SHOWERS AND STORMS AND SUB-VFR CONDITIONS WILL BE POSSIBLE OWING TO THE PASSAGE OF A FEW FAST-MOVING LOW PRESSURE SYSTEMS FROM LATE WED NIGHT THROUGH THE WEEKEND...BUT GENERALLY VFR CONDITIONS ARE OTHERWISE EXPECTED. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...CBL/WSS SHORT TERM...WSS LONG TERM...KC AVIATION...MWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1006 AM CDT TUE APR 24 2012 .DISCUSSION...THIS MORNING A WARM/STATIONARY FRONTAL BOUNDARY FROM SOUTHERN SASKATCHEWAN THROUGH CENTRAL SOUTH DAKOTA AND LYING ACROSS WESTERN NORTH DAKOTA WILL BE THE FOCUS FOR ISOLATED THUNDERSTORMS TODAY. SATELLITE PICS AND RADAR SHOW SOME SCATTERED SHOWERS NOW IN NORTH CENTRAL NORTH DAKOTA. THE LATEST HRRR MESO MODEL DOES INDICATE THIS AREA FOR FOCUS DURING THE NEXT 3 HOURS. SO ANTICIPATE THUNDERSTORMS INITIALLY IN THE NORTH CENTRAL MOVING SOUTHEAST. FROM THE SPC OUTLOOK THERE IS POTENTIAL FOR AN ISOLATED SEVERE STORM THIS AFTERNOON IF THE CELLS BREAK THE ELEVATED MIXED LAYER CAP. SO ADDED CHANCE FOR THUNDERSTORMS AND RAISED THE POPS NORTH CENTRAL. OTHERWISE CURRENT FORECAST LOOKS GOOD. && .AVIATION... A FEW SHOWERS WILL PERSIST INVOF KMOT THIS MORNING IN RESPONSE TO A WEAK SHORT WAVE TROUGH...AND HAVE INCLUDED A BRIEF VCSH MENTION THROUGH 17Z. ISOLATED HIGH BASED THUNDERSTORMS DURING THE LATE AFTERNOON AND EARLY EVENING HOURS WILL BE THE MAIN IMPACT THROUGH 25/12Z. AT THIS TIME...THE EXPECTED COVERAGE AND LOW PROBABILITY OF THUNDERSTORMS DO NOT WARRANT MORE THAN A CB GROUP IN TAFS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...WAA AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
945 AM CDT TUE APR 24 2012 .DISCUSSION...FORECAST CHALLENGE FOR UPDATE CONCERNS MAXIMUM TEMPERATURES AND CONVECTIVE POTENTIAL. SURFACE BOUNDARY EXTENDS FROM NW CORNER OF ND NEAR ISN TO SE CORNER OF SD NEAR FSD WITH SURFACE LOWS ACROSS S CENTRAL SASK AND FSD. BOUNDARY FORECAST BY MODELS TO REACH CENTRAL ND BY 00Z. REGION WILL REMAIN IN WARM SECTOR FOR THE DAY. CLOUD COVER AHEAD OF BOUNDARY SPARSE WITH MAINLY SOME SCT ACCAS WHICH SHOULD ALLOW FOR GOOD SOLAR TODAY. LAST TWO DAYS MAX TEMPERATURES HAVE BEEN UNDERESTIMATED SO WILL STICK WITH CURRENT FORECAST WHICH NUDGED MAX TEMPERATURES ABOVE FAVORED NUMERICAL GUIDANCE. WITH REGION IN WARM SECTOR RUC SHOWING RESPECTABLE INSTABILITY AND CAPE HOWEVER AIRMASS FAIRLY CAPPED WITH CONVECTIVE TEMPERATURES WELL INTO THE 80S ALONG WITH SUFFICIENT CIN TO INHIBIT CONVECTION. RUC MAY BE OVERDOING INSTABILITY AS IT BRINGS MID 50 DEWPOINTS WELL NORTH INTO ND WHICH MAY BE A LITTLE OVERDONE. LOW LEVEL MOIST AXIS EXTENDS FROM SE SD INTO CENTRAL ND NEAR BOUNDARY AND THIS LOOKS LIKE FAVORED AREA FOR ANY AFTERNOON DEVELOPMENT. BETTER CHANCE THIS EVENING WHEN MORE FAVORED UPPER SUPPORT ARRIVES SO WILL FORECAST DRY DURING THE DAY. && .AVIATION... VFR CONDITIONS TODAY WITH LIGHT SE WINDS AND INCREASING MID CLOUDS THIS AFTERNOON AND EVENING AS CHC OF TSTORMS OR SHRA DEVELOPS. WIND SHIFT OCCURS LATER TONIGHT AS COLD FRONT MOVES THROUGH. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
132 AM EDT TUE APR 24 2012 .SYNOPSIS... DEEP LOW PRESSURE OVER EASTERN NEW YORK WILL MOVE TO NORTH OF LAKE ONTARIO TONIGHT. THE LOW WILL WEAKEN AS IT MOVES NORTHEAST TUESDAY AND TUESDAY NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD NORTHEAST ACROSS THE LOCAL AREA TUESDAY AFTERNOON THROUGH WEDNESDAY. WEAK LOW PRESSURE WILL MOVE EAST ACROSS THE CENTRAL GREAT LAKES FORCING A COLD FRONT THROUGH THE AREA THURSDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... TOUGH OVERNIGHT FORECAST FOR THE LAKESHORE OF NW PA. ON THE EDGE ABOUT WHETHER A WARNING OR ADVISORY IS NEEDED. ANOTHER SURGE OF MOISTURE AND OMEGA IS EXPECTED OVERNIGHT AND THE NORTHWEST WINDS WILL BECOME MORE WEST NORTHWEST. THIS MAY BRING IN SOME BANDS OF LAKE EFFECT SNOW INTO THE LAKESHORE COUNTIES. WITH THE WIND AND THE SNOW BEING WET...THIS COULD CAUSE SOME PROBLEMS. LEFT THE WARNING GOING...BUT THE BEST CHANCE FOR SIGNIFICANT SNOWFALL WILL BE FROM INTERSTATE 90 AND SOUTH. OVER NORTHWEST OHIO SOME CLOUDS AND SOME WIND WILL OCCUR. EVEN THOUGH THE WINDS HAVE DECREASED AFTER SUNSET...THEY SHOULD INCREASE AGAIN...JUST ENOUGH TO KEEP THE LOWS FROM GETTING TOO COLD AND EXTENSIVE FROST. THUS NO HEADLINES FOR THAT AREA. ELSEWHERE OVER NORTHEAST OHIO...INCREASING CLOUDS. THE PRECIPITATION MAY NOT GET TOO FAR WEST OF ASHTABULA COUNTY. GOING WITH THE HRRR MODEL ON THIS...LOWERED THE POPS OVER PARTS OF NORTHEAST OHIO. MADE SOME ADJUSTMENTS TO THE LOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... WARM AIR ADVECTION BEGINS TOMORROW AS THE SURFACE LOW BEGINS TO LIFT NE. IT SHOULD BECOME WARM ENOUGH FOR ALL RAIN BY MIDDAY TUESDAY. HAVE SHORTENED THE WARNING BY A FEW HOURS. WESTERN AREAS SHOULD SEE A FAIR AMOUNT OF SUNSHINE. WEAK HIGH PRESSURE WILL BEGIN TO BUILD IN LATE TOMORROW AND THIS SHOULD END ANY LINGERING PRECIP TO THE EAST OF CLEVELAND TOMORROW EVENING. HIGH PRESSURE WILL REMAIN IN CONTROL WEDNESDAY. MODELS STILL SHOWING ANOTHER SYSTEM DIVING SE ACROSS THE REGION ON THURSDAY. HAVE ADJUSTED POPS SLIGHTLY. SUSPECT THAT WE WILL NEED LIKELY POPS FOR A PERIOD OR TWO. RIGHT NOW IT APPEARS BEST CHANCES FOR PRECIP WILL BE LATE WEDNESDAY NIGHT AND THURSDAY MORNING. A COLD FRONT WILL MOVE SE ACROSS THE REGION DURING THE DAY AND WILL TRY TO DRY THINGS OUT THURSDAY NIGHT. HAVE TRENDED SLIGHTLY COOLER THAN GUIDANCE THE NEXT COUPLE OF DAYS...ESPECIALLY IN NW PA WHERE THERE WILL BE SOME SNOW COVER. && .LONG TERM /FRIDAY THROUGH MONDAY/... LITTLE CHANGE FOR THE EXTENDED PERIOD. GFS CONTINUES TO MOVE LOW PRESSURE ACROSS THE OHIO VALLEY/LOWER GREAT LAKES WITH RAIN DEVELOPING ACROSS AREA ON SATURDAY. ECMWF ON THE OTHER HAND CONTINUES TO BE FURTHER NORTH WITH THE LOW AND 6-12 HOURS SLOWER WITH THE RAIN. SINCE LOW CONFIDENCE CONTINUED WITH CHANCE POPS SATURDAY INTO SUNDAY. KEPT MONDAY DRY AND A LITTLE WARMER AS HIGH PRESSURE BUILDS OVER THE AREA. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... SURFACE LOW OVER SOUTHEAST ONTARIO WILL MOVE NORTH TO QUEBEC TODAY. MOISTURE CONTINUES TO ROTATE AROUND THE LOW AND INTO NORTHEAST OHIO AND NORTHWEST PA ALTHOUGH MOST PRECIP HAS BEEN OVER NWRN PA. MODELS SHOW MOISTURE ROTATING BACK WEST INTO NERN OHIO AFTER 15Z AS A SHORT WAVE DROPS ACROSS THE AREA. A VERY LEAST WOULD EXPECT A LOWER OR MID DECK CIG TO GET BACK INTO KCLE AND KCAK FOR THE LATE MORNING AND EARLY AFTERNOON. COULD ALSO SEE A FEW SNOW SHOWERS BUT AT PRESENT DO NOT EXPECT MORE THAN A FLURRY. KYNG BROUGHT IN AN MVFR CIGS WITH MVFR SNOW SHOWERS AS LOWER LEVEL MOISTURE SEEMS TO GET INTO THE AREA. KERI SHOULD CONTINUE TO BE IN AND OUT OF RAIN/SNOW SHOWERS AND THEREFORE IN AND OUT OF MVFR CONDITIONS THROUGH MUCH OF THE PERIOD. WINDS WILL AGAIN BECOME GUSTY FROM THE NORTHWEST DURING THE LATE MORNING AND AFTERNOON HOURS. TOOK WINDS TO ABOUT 20 KNOTS WITH GUSTS AROUND 30. .OUTLOOK...NON VFR LIKELY AGAIN WEDNESDAY NIGHT AND THURSDAY. NON VFR RETURNING ON SATURDAY. && .MARINE... LOW PRESSURE OVER EASTERN NEW YORK WILL LINGER OVER NEW YORK STATE TONIGHT AND THEN GRADUALLY MOVE NORTH INTO ONTARIO AND QUEBEC ON TUESDAY. THE GALE WARNING HAS BEEN CANCELLED FOR AREAS WEST OF VERMILLION AS WINDS HAVE DROPPED TO 15 TO 20 KNOTS. SOME INCREASE IN WINDS IS POSSIBLE ACROSS CENTRAL AND EASTERN LAKE ERIE OVERNIGHT SO HAVE LEFT THE GALE WARNING IN EFFECT WITH WINDS TO 35 KNOTS FOR THE OVERNIGHT HOURS. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR NEARSHORE WATERS WEST OF VERMILLION AND WILL BE NEEDED FOR THE REMAINDER OF THE NEARSHORE WATERS ON TUESDAY AS NORTHWEST WINDS OF 15 TO 25 KNOTS CONTINUE TO GENERATE HIGH WAVES ALONG THE LAKESHORE. WINDS AND WAVES WILL DECREASE TUESDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS OVER THE LAKE. HIGH PRESSURE WILL MOVE TO THE EAST AS LOW PRESSURE AND A COLD FRONT MOVES ACROSS THE LAKE THURSDAY. NORTHWEST WINDS MAY BE STRONG ENOUGH TO CAUSE SMALL CRAFT ADVISORY CONDITIONS THURSDAY NIGHT...BUT THEN WINDS SHOULD DIMINISH AS A RIDGE BUILDS OVER THE LAKE FRIDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...WINTER STORM WARNING UNTIL 11 AM EDT THIS MORNING FOR PAZ001>003. MARINE...GALE WARNING UNTIL 5 AM EDT EARLY THIS MORNING FOR LEZ061- 145>149-165>169. SMALL CRAFT ADVISORY UNTIL 4 AM EDT WEDNESDAY FOR LEZ142>144. && $$ SYNOPSIS...KUBINA NEAR TERM...KIELTYKA SHORT TERM...KUBINA LONG TERM...DJB AVIATION...TK MARINE...ABE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
929 PM CDT WED APR 25 2012 .UPDATE... LATEST WRF AND RUC SOLUTIONS NOT SHOWING MUCH IN THE WAY OF REDEVELOPMENT ACROSS OUR SOUTHWESTERN COUNTIES. THE 18Z GFS RUN DOES SHOW AN AREA OF CONVECTION MOVING ACROSS MUCH OF THE WESTERN PORTIONS OF THE MID STATE AFTER 06Z. HOWEVER...THIS ACTIVITY IS IN THE FORM OF AN MCS WHICH IS EXPECTED TO MOVE SOUTHEAST FROM MO. LATEST RADAR IMAGERY IS NOT SHOWING MUCH IN THE WAY OF DEVELOPMENT THERE. THEREFORE...WILL LOWER POPS...PARTICULARLY ACROSS SOUTHEASTERN ZONES. REMAINDER OF FCST LOOKS OK. && KOHXZFPOHX.PREV DISCUSSION... /ISSUED 656 PM CDT WED APR 25 2012/ UPDATE...FOR 00Z AVIATION DISCUSSION. AVIATION...00Z AVIATION DISCUSSION. WILL MENTION VCSH THRU 26/13Z PER CONFIDENCE IN OCCURRENCE/BUT LOCATION UNCERTAINTY. PROGRESSIVE WRLY LLJ STRUCTURE WILL RESULT IN LLWS AT TAF SITES AROUND 26/06Z-26/11Z. WITH SHORTWAVE EXPECTED TO MOVE INTO MID STATE AFTER 26/06Z...WILL NOT MENTION TSRA UNTIL 26/06Z-26/10Z. BELIEVE ACTIVITY WILL WEAKEN BY 26/13Z WITH IFR CEILING PREDOMINATE. CEILINGS SHOULD LIFT INTO THE MVFR RANGE BY 26/15Z-26/16Z WITH A COLD FRONT SAGGING SWD INTO MID STATE BY 26/18Z...PROVIDING A FOCUSING MECHANISM FOR SCT SHWRS/TSTMS...WITH LOCATION UNCERTAINTY...THRU 26/24Z. PREV DISCUSSION.../ISSUED 606 PM CDT WED APR 25 2012/ UPDATE... FRONTAL BOUNDARY LOCATED WELL TO THE NW OF MIDDLE TN AND IS LOCATED ACROSS NORTHERN MO AND SW THROUGH SRN KN. SHORTWAVE IMPULSES AND NOT EXPECTED TO ARRIVE UNTIL LATE TONIGHT. THUS...WITH A RATHER INACTIVE RADAR RIGHT NOW...WILL OPT TO ADJUST THE ONE WORDING TO REFLECT AFT MIDNIGHT WORDING. THROUGH THIS EVENING THE ACTIVITY LOOKS ISOLATED TO SCT AT BEST. OTW...REMAINDER OF FCST APPEARS TO BE IN GOOD SHAPE. DEW POINTS ACROSS THE AREA ARE IN THE LOWER 60S WHICH IS THE FCST LOW. SOUTHERLY WIND FLOW OF 5-15 MPH EXPECTED TO CONTINUE OVERNIGHT. WILL MAKE GRID ADJUSTMENTS TO INCREASE CLOUD COVERAGE ACROSS THE SOUTH. ALSO...WILL INCLUDE A 6HR SPLIT OF THE WEATHER GRIDS. UPDATE OUT SHORTLY. PREV DISCUSSION... /ISSUED 243 PM CDT WED APR 25 2012/ DISCUSSION... WARM FRONT HAS LIFTED NORTH AND INTO KENTUCKY AT MID AFTERNOON. A FEW SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED ALONG AND SOUTH OF WARM FRONTAL BOUNDARY AND IN WESTERN KENTUCKY AND WESTERN TENNESSEE THIS AFTERNOON. THIS HAS BEEN MAINLY WARM ADVECTION TYPE SHOWERS AND STORMS. SURFACE TEMPS HAVE WARMED INTO THE 70S AT MANY LOCATIONS WITH 83 AT NASHVILLE. MOISTURE IS INCREASING IN THE LOWER LEVELS THIS AFTERNOON BUT SLOWLY WITH DEWPOINT TEMPS CURRENTLY MOSTLY IN THE 50S. AS UPPER LEVEL FLOW CONTINUES OUT OF THE NORTHWEST TONIGHT MID STATE WILL BE IN WARM SECTOR WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS. BELIEVE A BETTER CHANCE WILL COME TOWARD MIDNIGHT NEAR KENTUCKY BORDER AND EXPECT THIS ACTIVITY TO SINK SOUTHWARD DURING THE LATE NIGHT. THIS IS DUE IN PART TO A SHORT WAVE THAT WILL BE DROPPING SOUTHEAST EMBEDDED IN NORTHWEST FLOW ALOFT. A WEAK COOL FRONT WILL ALSO APPROACH FROM THE NORTHWEST AND EXTEND ALONG THE OHIO RIVER BACK DOWN THROUGH SOUTHEAST MISSOURI AROUND 12Z THURSDAY. THINK BEST SEVERE THREAT WILL BE ACROSS OHIO VALLEY TONIGHT. COULD SEE AN MCS DEVELOP THIS EVENING OVER CENTRAL AND SOUTHERN ILLINOIS SO WILL KEEP AN EYE OUT TO THE NORTHWEST. COOL FRONT PULLS UP ALONG TENNESSEE/KENTUCKY BORDER ON THURSDAY THEN LIFTS BACK NORTH LATE IN THE DAY AS A WARM FRONT. SO EXPECT TO SEE SCATTERED SHOWERS AND STORMS ON THURSDAY. IN FACT IT LOOKS LIKE AN UNSETTLED PERIOD COMING UP FOR THE NEXT SEVERAL DAYS WITH SHOWER AND STORM CHANCES. LOOKS LIKE TEMPS WILL AVERAGE ABOVE CLIMATOLOGY FOR THE NEXT SEVEN DAYS. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
616 PM CDT WED APR 25 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY 338 PM CDT WED APR 25 2012 AT 3 PM...A SURFACE LOW WAS LOCATED JUST WEST OF CHARLES CITY IOWA. A WARM FRONT EXTENDED SOUTHEAST OF THIS LOW INTO CENTRAL ILLINOIS...AND A COLD FRONT EXTENDED WEST ACROSS WEST-CENTRAL IOWA. TEMPERATURES ACROSS WESTERN AND SOUTHERN IOWA HAVE WARMED WELL INTO THE 80S. THERE WERE EVEN A FEW 90S. MEANWHILE NORTH OF THE WARM FRONT...THE TEMPERATURES RANGED FROM THE 40S ACROSS NORTHERN WISCONSIN TO THE 60S ACROSS MUCH OF OUR FORECAST AREA. ML CAPES HAVE CLIMB UP TO 250 J/KG ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN WHICH WAS JUST ENOUGH INSTABILITY FOR THE LOW PRESSURE AREA TO GENERATE A FEW SHOWERS ACROSS THIS AREA. THE LATEST HRRR AND SPC WRF SHOW THAT THESE SHOWERS WILL MOVE SOUTHEAST OF THE AREA BY 6 PM. FURTHER TO THE NORTHWEST SOME ADDITIONAL SHOWERS WERE MOVING EAST SOUTHEAST ACROSS NORTHERN WISCONSIN. THESE SHOWERS WERE ASSOCIATED WITH A POTENTIAL VORTICITY ANOMALY MOVING SOUTHEAST ACROSS NORTHERN AND EASTERN WISCONSIN. THESE SHOWERS HAVE BEEN MAINLY EAST AND NORTH OF TAYLOR COUNTY...SO JUST WENT DRY THERE FOR TONIGHT. ON THURSDAY...HIGH PRESSURE WILL NOSE SOUTHWARD INTO THE UPPER MISSISSIPPI RIVER VALLEY. WITH ABUNDANT SUNSHINE...MUCH OF THE AREA WILL MIX UP TO AROUND 850 MB. AS THIS OCCURS...DRIER AIR FROM ALOFT WILL MIX TO THE SURFACE. THIS WILL LOW THE DEW POINTS TO AROUND 20 NORTH OF THE INTERSTATE 94 CORRIDOR...AND IN THE LOWER AND MID 20S ACROSS THE REMAINDER OF THE AREA. THIS IS ABOUT 3 TO 5 DEGREES LOWER THAN THE MOS DEW POINTS. ON THURSDAY NIGHT...THE DEW POINTS WILL REMAIN RATHER DRY. THIS WILL ALLOW THE TEMPERATURES TO DROP OFF RATHER RAPIDLY ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. LOW TEMPERATURES ACROSS THIS AREA WILL LIKELY FALL INTO THE MID AND UPPER 20S. WITH TEMPERATURE AND DEW POINT SPREADS GREATER THAN 8F...CONCERNED THAT THERE WILL BE NO FROST DEVELOPMENT. HOWEVER THESE TEMPERATURES WILL STILL BE COLD ENOUGH TO CAUSE SOME DAMAGE TO UNPROTECTED FRUIT CROPS AND COLD-SENSITIVE FLOWERS. MEANWHILE FURTHER WEST AND SOUTH...THERE WILL INCREASE IN THE CLOUD COVER FROM THE LATE EVENING INTO THE OVERNIGHT. THIS WILL TEMPER THE POTENTIAL FALL IN THE TEMPERATURES AND FROST DEVELOPMENT IN THOSE AREAS. FROM FRIDAY INTO SATURDAY...A LONG WAVE TROUGH WILL BE DIGGING INTO THE WESTERN CONUS. AS THIS OCCURS...THE RIDGE WILL BE AMPLIFYING ACROSS THE CENTRAL UNITED STATES AND CANADIAN PRAIRIES. THIS PATTERN SHIFT STARTED TO DEVELOP LAST NIGHT AND CONTINUED INTO TODAY. AS A RESULT...THE STRONG 800 TO 500 MB FRONTOGENESIS HAS MOVED BACK NORTHWARD INTO SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHERN HALF OF WISCONSIN. DUE TO THIS...THE PRECIPITATION PROBABILITIES WERE RAISED AND MOVED NORTH. 25.12Z GFS AND NAM/WRF BUFKIT SOUNDINGS SUGGEST THAT THE COLUMN WILL BE COLD ENOUGH AND THERE WILL BE THE INTRODUCTION OF ICE CRYSTALS AT TIMES FOR THE RAIN TO CHANGE OVER TO SNOW AT TIMES IN THESE AREAS. THE 25.12Z ECMWF AND 25.18Z NAM/WRF ALSO SHOWS POSSIBILITY. HOWEVER IT IS A BIT FURTHER NORTH AND EAST. THIS MAY SHIFT EVEN FURTHER NORTHWEST IF THE TROUGH IN THE WESTERN CONUS DIGS EVEN MORE. SINCE THE POSSIBILITY OF SNOW HAS BEEN CONSISTENT FOR THE LAST 3 MODEL RUN...JUST INTRODUCED A CHANCE OF SNOW AT THIS TIME. IN ADDITION WITH MORE PRECIPITATION AND CLOUD COVER EXPECTED...HIGH TEMPERATURES FOR SATURDAY HAD TO BE COOLED A FEW MORE DEGREES...AND THIS MAY NOT BE ENOUGH YET. THE FORECAST FOR THIS TIME PERIOD WILL LIKELY REMAIN RATHER FLUENT UNTIL THIS SYSTEM IS SAMPLED FULLY BY THE UPPER AIR NETWORK ON THURSDAY NIGHT. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 338 PM CDT WED APR 25 2012 ON SATURDAY NIGHT...WE MAY HAVE THE POTENTIAL FOR ANOTHER FROST OR FREEZE AS A HIGH PRESSURE SYSTEM BUILD ACROSS THE REGION. THE MAIN QUESTION AT THIS TIME IS HOW FAST WILL THE AREA CLEAR OUT AND WHEN THE WINDS MAY DECOUPLE. FROM MONDAY NIGHT THROUGH WEDNESDAY...THE 25.12Z MODELS CONTINUE TO STRUGGLE ON THE TIMING OF A LONG WAVE TROUGH MOVING OUT OF THE CENTRAL PLAINS. THE ECMWF IS ABOUT 12 HOURS SOONER THAN THE GFS AND HAS ITS PRECIPITATION CHANCES RUNNING FROM MONDAY NIGHT INTO TUESDAY. WITH THE MODELS CONTINUING TO STRUGGLE WITH ITS TIMING JUST STAYED WITH THE ALL BLEND TIMING FOR NOW. && .AVIATION...TONIGHT AND THURSDAY 615 PM CDT WED APR 25 2012 BAND OF MID LEVEL CLOUDS ASSOCIATED WITH AN AREA OF LOW PRESSURE OVER SOUTHERN IOWA ARE MOVING SOUTH AND SHOULD CLEAR BOTH TAF SITES EARLY THIS EVENING. A TROUGH OF LOW PRESSURE EXTENDS NORTH THROUGH MINNESOTA FROM THE MAIN SURFACE LOW. AN AREA OF VFR CEILINGS AROUND 4 TO 5 THOUSAND FEET IS SLOWLY EXPANDING AS IT MOVES SOUTH/SOUTHEAST ON THE EAST SIDE OF THIS TROUGH OF LOW PRESSURE. THE 25.18Z NAM BUFKIT SOUNDING SUGGESTS THESE CLOUDS WILL GET INTO BOTH TAF SITES OVERNIGHT BUT WITH THE CURRENT MOVEMENT THEY COULD ALSO SLIP OFF TO THE EAST. FOR NOW...HAVE INCLUDED SOME SCATTERED CLOUDS ABOUT THE TIME THEY SHOULD ARRIVE IF THEY HOLD TOGETHER. SOME STEEP LOW LEVEL LAPSE RATES WILL QUICKLY DEVELOP AFTER SUNRISE THURSDAY TO ALLOW FOR A PERIOD OF SOME GUSTY WINDS AT KRST BEFORE HIGH PRESSURE BUILDS IN DIMINISHING THE WINDS IN THE MIXED LAYER ALLOWING THE GUSTS TO DISSIPATE DURING THE MID TO LATE AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... 338 PM CDT WED APR 25 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
552 PM CDT TUE APR 24 2012 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW PRESSURE SITUATED OVER SE SASKATCHEWAN EARLY THIS AFTERNOON...AND WARM FRONT STRETCHING SOUTHEAST OVER THE NORTHERN PLAINS. WISCONSIN STILL RESIDES WITHIN CYCLONIC AND NORTHERLY FLOW AROUND A DEEP LOW PRESSURE SYSTEM OVER QUEBEC. MID-LEVEL MOISTURE...DIURNAL HEATING...AND DEEP MIXING HAS CONTRIBUTED TO A WIDESPREAD CU FIELD OVER NE WISCONSIN. TEMPS HAVE WARMED QUICKLY TODAY INTO THE 60S EXCEPT NEAR LAKE MICHIGAN AND OVER FAR NORTHERN WISCONSIN. AS LOW PRESSURE MOVE SE FROM THE NORTHERN PLAINS INTO ILLINOIS TONIGHT INTO WEDNESDAY...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LOW PRESSURE OVER SE SASKATCHEWAN WILL SLIDE SE ALONG A BAROCLINIC ZONE STRETCHING FROM THE NORTHERN PLAINS TO THE OHIO VALLEY. FGEN NORTH OF THIS BAROCLINIC ZONE OVER SASKATCHEWAN AND MANITOBA WILL SLIDE SE AS WELL INTO THE NORTHERN MISSISSIPPI VALLEY BY 12Z WEDNESDAY. THOUGH CLOUDS WILL BE INCREASING AHEAD OF THE FGEN BAND LATE TONIGHT...AND LOWERING AS WELL...AM COUNTING ON DRY SE FLOW IN THE LOW LEVELS TO KEEP PRECIP WEST OF THE REGION TONIGHT. INHERITED LOW CHANCE POPS OVER NORTH-CENTRAL WISCONSIN...AND WILL KEEP THEM JUST IN CASE SHOWERS BECOME A TAD MORE AMBITIOUS THAN THE CURRENT THINKING. TEMPERATURES RANGING FROM THE MID 30S NORTH TO LOW 40S SOUTH. WEDNESDAY...MODELS HAVE COME INTO BETTER AGREEMENT TRACKING THE SURFACE LOW PRESSURE FROM SW MINNESOTA TO NORTHWEST ILLINOIS BY 00Z THU. THE TIGHTER BAROCLINIC ZONE UPSTREAM WILL SHIFT EAST INTO SW WISCONSIN...WITH MID-LEVEL FGEN AND UPPER DIVERGENCE INCREASING ACROSS THE AREA DURING THE MORNING...THEN PASSING ACROSS THE AREA DURING THE AFTERNOON. THIS SHOULD LEAD TO A PRETTY GOOD SWATH OF SHOWERS THROUGH THE DAY OVER CENTRAL WISCONSIN WHERE THE BEST FORCING WILL RESIDE...THOUGH ALL AREAS STAND TO GET SOME RAIN. WILL INCREASE POPS AND QPF. CLOUDS...RAIN...AND SE FLOW WILL LEAD TO A CONSIDERABLY COOLER DAY. HAVE SIDED WITH THE COOLER GUIDANCE WHICH PLACES HIGHS IN THE MID 50S NORTH TO NEAR 60 SOUTH. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY...MAIN FCST CONCERNS ARE PCPN TRENDS WEDS NGT...POTENTIAL FOR MORE HARD FREEZES LATE IN THE WEEK...THEN WHETHER OR NOT TO KEEP SMALL POPS IN THE FCST FOR THE WEEKEND. ISENT LIFT AND ASSOCIATED SHOWERS WILL BE ONGOING EARLY WEDS EVENING...IN ADVANCE OF A COLD FRONT. IN ADDITION...A SHORT-WAVE TROF IS EXPECTED TO BRUSH PAST NE WI DURING THE NIGHT. HAVE RAISED POPS TO LIKELY OVER FAR NE WI FOR THE EVG HOURS...THEN CONTINUED THE TREND OF DECREASING SHOWERS FOR THE OVERNIGHT PERIOD. CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD FRONT ON THURSDAY AND FRIDAY...BRINGING DRY AND COOLER CONDITIONS. SUB-FREEZING TEMPERATURES APPEAR LIKELY OVER NEARLY ALL OF THE CWA ON THURSDAY NIGHT. LOWERED MIN TEMPS OVER THE ENTIRE AREA...WITH READINGS AS LOW AS 20 IN THE TYPICAL COLD SPOTS IN NC WI. WOULD NOT BE SURPRISED IF A FEW LOCATIONS GET INTO THE TEENS. MODELS HAVE TRENDED FARTHER SOUTH WITH LOW PRESSURE MOVG THROUGH THE UPPER MIDWEST OVER THE WEEKEND...AND KEEP C/NE WI ENTRENCHED IN DRY AIR FEEDING OUT OF THE MASSIVE CANADIAN HIGH. HAVE REMOVED ALL PCPN FROM THE WEEKEND FCST...AND DON`T BRING ANY RAIN BACK INTO THE FCST UNTIL THE CANADIAN HIGH SHIFTS EAST MONDAY NIGHT INTO TUESDAY. THIS WILL MEAN THAT THERE WILL BE CONTINUED POTENTIAL FOR FREEZING NIGHTTIME TEMPERATURES DURING THIS PERIOD...SO THOSE WITH AGRICULTURAL CONCERNS SHOULD STAY TUNED TO THE LATEST FCSTS. && .AVIATION...MID LEVEL VFR CIGS WILL INCREASE FROM THE NORTH OVERNIGHT. CIGS WILL LOWER TO AROUND 4000 TO 5000 FT LEVELS ON WEDNESDAY AS RAIN SPREADS OVER THE AREA. TDH && .FIRE WEATHER...ALTHOUGH SHOWER ACTIVITY WILL RESULT IN A BRIEF REPRIEVE FROM THE LOW HUMIDITY ON WEDNESDAY...A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL RETURN TO THE REGION ON THURSDAY... AND REMAIN OVER THE AREA THROUGH ABOUT NEXT MONDAY. WITH VERY DRY AIR ENTRENCHED OVER THE REGION...HUMIDITY READINGS WILL LIKELY DROP TO NEAR CRITICAL LEVELS AGAIN FOR THE END OF THE WORK WEEK AND THE WEEKEND. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
239 PM CDT TUE APR 24 2012 .SHORT TERM...TONIGHT AND WEDNESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW PRESSURE SITUATED OVER SE SASKATCHEWAN EARLY THIS AFTERNOON...AND WARM FRONT STRETCHING SOUTHEAST OVER THE NORTHERN PLAINS. WISCONSIN STILL RESIDES WITHIN CYCLONIC AND NORTHERLY FLOW AROUND A DEEP LOW PRESSURE SYSTEM OVER QUEBEC. MID-LEVEL MOISTURE...DIURNAL HEATING...AND DEEP MIXING HAS CONTRIBUTED TO A WIDESPREAD CU FIELD OVER NE WISCONSIN. TEMPS HAVE WARMED QUICKLY TODAY INTO THE 60S EXCEPT NEAR LAKE MICHIGAN AND OVER FAR NORTHERN WISCONSIN. AS LOW PRESSURE MOVE SE FROM THE NORTHERN PLAINS INTO ILLINOIS TONIGHT INTO WEDNESDAY...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LOW PRESSURE OVER SE SASKATCHEWAN WILL SLIDE SE ALONG A BAROCLINIC ZONE STRETCHING FROM THE NORTHERN PLAINS TO THE OHIO VALLEY. FGEN NORTH OF THIS BAROCLINIC ZONE OVER SASKATCHEWAN AND MANITOBA WILL SLIDE SE AS WELL INTO THE NORTHERN MISSISSIPPI VALLEY BY 12Z WEDNESDAY. THOUGH CLOUDS WILL BE INCREASING AHEAD OF THE FGEN BAND LATE TONIGHT...AND LOWERING AS WELL...AM COUNTING ON DRY SE FLOW IN THE LOW LEVELS TO KEEP PRECIP WEST OF THE REGION TONIGHT. INHERITED LOW CHANCE POPS OVER NORTH-CENTRAL WISCONSIN...AND WILL KEEP THEM JUST IN CASE SHOWERS BECOME A TAD MORE AMBITIOUS THAN THE CURRENT THINKING. TEMPERATURES RANGING FROM THE MID 30S NORTH TO LOW 40S SOUTH. WEDNESDAY...MODELS HAVE COME INTO BETTER AGREEMENT TRACKING THE SURFACE LOW PRESSURE FROM SW MINNESOTA TO NORTHWEST ILLINOIS BY 00Z THU. THE TIGHTER BAROCLINIC ZONE UPSTREAM WILL SHIFT EAST INTO SW WISCONSIN...WITH MID-LEVEL FGEN AND UPPER DIVERGENCE INCREASING ACROSS THE AREA DURING THE MORNING...THEN PASSING ACROSS THE AREA DURING THE AFTERNOON. THIS SHOULD LEAD TO A PRETTY GOOD SWATH OF SHOWERS THROUGH THE DAY OVER CENTRAL WISCONSIN WHERE THE BEST FORCING WILL RESIDE...THOUGH ALL AREAS STAND TO GET SOME RAIN. WILL INCREASE POPS AND QPF. CLOUDS...RAIN...AND SE FLOW WILL LEAD TO A CONSIDERABLY COOLER DAY. HAVE SIDED WITH THE COOLER GUIDANCE WHICH PLACES HIGHS IN THE MID 50S NORTH TO NEAR 60 SOUTH. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY...MAIN FCST CONCERNS ARE PCPN TRENDS WEDS NGT...POTENTIAL FOR MORE HARD FREEZES LATE IN THE WEEK...THEN WHETHER OR NOT TO KEEP SMALL POPS IN THE FCST FOR THE WEEKEND. ISENT LIFT AND ASSOCIATED SHOWERS WILL BE ONGOING EARLY WEDS EVENING...IN ADVANCE OF A COLD FRONT. IN ADDITION...A SHORT-WAVE TROF IS EXPECTED TO BRUSH PAST NE WI DURING THE NIGHT. HAVE RAISED POPS TO LIKELY OVER FAR NE WI FOR THE EVG HOURS...THEN CONTINUED THE TREND OF DECREASING SHOWERS FOR THE OVERNIGHT PERIOD. CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF THE COLD FRONT ON THURSDAY AND FRIDAY...BRINGING DRY AND COOLER CONDITIONS. SUB-FREEZING TEMPERATURES APPEAR LIKELY OVER NEARLY ALL OF THE CWA ON THURSDAY NIGHT. LOWERED MIN TEMPS OVER THE ENTIRE AREA...WITH READINGS AS LOW AS 20 IN THE TYPICAL COLD SPOTS IN NC WI. WOULD NOT BE SURPRISED IF A FEW LOCATIONS GET INTO THE TEENS. MODELS HAVE TRENDED FARTHER SOUTH WITH LOW PRESSURE MOVG THROUGH THE UPPER MIDWEST OVER THE WEEKEND...AND KEEP C/NE WI ENTRENCHED IN DRY AIR FEEDING OUT OF THE MASSIVE CANADIAN HIGH. HAVE REMOVED ALL PCPN FROM THE WEEKEND FCST...AND DON`T BRING ANY RAIN BACK INTO THE FCST UNTIL THE CANADIAN HIGH SHIFTS EAST MONDAY NIGHT INTO TUESDAY. THIS WILL MEAN THAT THERE WILL BE CONTINUED POTENTIAL FOR FREEZING NIGHTTIME TEMPERATURES DURING THIS PERIOD...SO THOSE WITH AGRICULTURAL CONCERNS SHOULD STAY TUNED TO THE LATEST FCSTS. && .AVIATION...SCT TO BKN MID DECK OVER EASTERN WISCONSIN THIS AFTERNOON AS DEEP MIXING GENERATES DIURNAL CU. CLOUDS WILL BE ON THE INCREASE AND LOWER THROUGH THE NIGHT AS A STORM SYSTEM OVER THE NORTHERN PLAINS MOVES SOUTHEAST INTO THE NORTHERN MISSISSIPPI VALLEY. SHOWERS FROM THE WEST WILL PUSH ACROSS THE AREA DURING THE MORNING HOURS AS SOUTHEAST WINDS DEVELOP. HAVE LEFT CONDITIONS VFR AS DRY AIR WILL LIKELY ERODE CLOUD COVER AND PRECIP AS THEY ARRIVE. CONDITIONS TO FALL TO MVFR TOMORROW AFTERNOON ONCE THE LOW LEVELS MOISTEN. MPC && .FIRE WEATHER...ALTHOUGH SHOWER ACTIVITY WILL RESULT IN A BRIEF REPRIEVE FROM THE LOW HUMIDITY ON WEDNESDAY...A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL RETURN TO THE REGION ON THURSDAY... AND REMAIN OVER THE AREA THROUGH ABOUT NEXT MONDAY. WITH VERY DRY AIR ENTRENCHED OVER THE REGION...HUMIDITY READINGS WILL LIKELY DROP TO NEAR CRITICAL LEVELS AGAIN FOR THE END OF THE WORK WEEK AND THE WEEKEND. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MPC/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS TUCSON AZ
905 PM MST WED APR 25 2012 .SYNOPSIS...A STRONG LOW PRESSURE SYSTEM ON THURSDAY WILL BRING GUSTY WINDS...MUCH COOLER TEMPERATURES...AND A FEW SHOWERS TO THE AREA. DRY CONDITIONS WITH A WARMING TREND WILL START FRIDAY AND CONTINUE INTO EARLY NEXT WEEK. && .DISCUSSION...UPPER LOW APPROACHING THE SRN CALIFORNIA COAST WITH ABUNDANT MID AND HIGH-LEVEL CLOUDS MOVING NEWD ACROSS SE AZ AT THIS TIME. LIGHTNING STRIKES HAVE BEEN DETECTED THIS EVENING ASSOCIATED JUST AHEAD OF THE UPPER LOW PRESSURE SYSTEM. 26/00Z NAM DEPICTS PRECIP-FREE CONDITIONS ACROSS SE AZ THRU 26/09Z...THEN A FEW HUNDREDTHS OF AN INCH DEVELOPS SOUTH OF TUCSON ACROSS SANTA CRUZ COUNTY AS WELL AS ACROSS WRN PIMA COUNTY AROUND SUNRISE THUR. THEREAFTER...NAM AND RUC HRRR WERE SIMILAR WITH KEEPING MEASURABLE PRECIP NORTH OF TUCSON ON THUR. HAVE NOTED THAT THE SUSTAINED WINDS FOR KDUG VIA THE NAM MOS GUIDANCE PRODUCT WOULD ACHIEVE WIND ADVISORY CRITERIA THUR AFTERNOON. NO UPDATES PLANNED AT THIS TIME. PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION FOR ADDITIONAL DETAIL. && .PREV DISCUSSION...MODELS INDICATE THAT THE UPPER LOW WILL MOVE VERY CLOSE TO THE EXTREME SOUTHERN CALIFORNIA COAST BY AROUND MIDNIGHT TONIGHT...THEN ACROSS SOUTHWEST ARIZONA BY MIDDAY THURSDAY. THE MODELS SUGGEST THAT PRECIPITABLE WATER VALUES WILL INCREASE WITH A THIN BAND OF 1 INCH PW AMOUNTS MAINLY TO THE WEST OF TUCSON OVER THE FAR WESTERN DESERTS OF PIMA COUNTY AND INTO WESTERN MARICOPA COUNTY BETWEEN 12 AND 18Z. DURING THE AFTERNOON HOURS THE PW`S DROP OFF WELL BELOW THREE QUARTERS OF AN INCH. MOS POP NUMBERS WITH THIS SYSTEM ARE EXTREMELY LOW...AT LEAST THIS FAR SOUTH. THE 12Z NAM MOS POP FOR TUCSON IS ONLY SHOWING 3 PERCENT FOR THURSDAY AND THE GFS ONLY 23 PERCENT. MOS NUMBERS ARE HIGHER TO THE NORTH TOWARD THE PHOENIX AREA...BUT THIS FAR SOUTH THE THREAT FOR PRECIP SHOULD BE FAIRLY LOW. THAT SAID...I ONLY MADE SOME MINOR CHANGES TO THE POPS AND KEPT THE TREND OF LOWERING POPS THAT THE MIDNIGHT SHIFT STARTED LAST NIGHT. BASICALLY THIS MEANS A FAIRLY STEEP POP GRADIENT WILL EXIST ACROSS MY FORECAST AREA FROM SOUTH TO NORTH WITH HIGHER POPS OVER THE CENTRAL AND NORTHERN PORTIONS OF THE STATE. THE SYSTEM QUICKLY EXITS THE REGION TO THE NORTHEAST LATE THURSDAY. NORTHWEST TO NEARLY ZONAL FLOW ALOFT WILL RESIDE ACROSS THE DESERT SOUTHWEST THROUGH SATURDAY AS WEAK DISTURBANCES MOVE THROUGH THE FLOW TO OUR NORTH. BY LATE THIS WEEKEND AND EARLY NEXT WEEK A BAGGY TROUGH DEVELOPS ACROSS THE WEST AND THEN THE MODELS BEGIN TO DIVERGE IN THEIR SOLUTIONS BY MONDAY. AT ANY RATE IT LOOKS LIKE A DRY FORECAST THROUGH NEXT WEDNESDAY. HIGHS WILL GENERALLY BE 2 TO 5 DEGS BELOW NORMAL THURSDAY AND FRIDAY...THEN 2 TO 4 DEGS ABOVE NORMAL FOR SATURDAY. THEREAFTER... HIGHS WILL BE 5 TO 7 DEGS ABOVE NORMAL. LOWS WILL BE 10 TO 12 DEGS ABOVE NORMAL TONIGHT/EARLY THURSDAY...THEN SLIGHTLY BELOW NORMAL FRIDAY. A WARMING TREND WILL BEGIN ON SATURDAY AND LOWS WILL BE AROUND 3 TO 6 DEGS ABOVE NORMAL SUNDAY THROUGH WEDNESDAY. && .AVIATION...SCT-BKN CLOUDS MOSTLY ABOVE 15K FT AGL THE REST OF TONIGHT THEN CLOUD DECKS LOWERING TO 5-10K FT AGL AROUND DAYBREAK THURSDAY AND CONTINUING THRU THURSDAY AFTERNOON. ISOLD-SCT -SHRA AND A SLIGHT CHANCE OF -TSRA MAINLY NORTH OF KTUS THURSDAY. DECREASING CLOUDINESS THURSDAY AFTERNOON THEN SKC BY FRIDAY MORNING. SURFACE WIND GENERALLY LESS THAN 10 KTS THRU EARLY THURSDAY MORNING...THEN SURFACE WIND WLY/SWLY 15-25 KTS WITH GUSTS TO 40 KTS THURSDAY AFTERNOON. SURFACE WIND GENERALLY LESS THAN 10 KTS THURSDAY NIGHT. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...STRONGER WINDS ARE EXPECTED ON THURSDAY AS A STORM SYSTEM MOVES ACROSS THE STATE. THIS SYSTEM WILL RESULT IN MUCH COOLER TEMPERATURES...A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS THURSDAY. A RAPID WARMING TREND WILL THEN OCCUR BEHIND THE SYSTEM FRIDAY AND SATURDAY. WITH THE STRONGER WINDS ON THURSDAY...FAR EASTERN AREAS WHERE THE MOISTURE MOVES IN LAST...MAY BRIEFLY APPROACH CRITICAL FIRE WEATHER THRESHOLDS THURSDAY AFTERNOON. THE AREA OF STRONGER WINDS AND LOW RELATIVE HUMIDITIES IS NOT EXPECTED TO BE WIDESPREAD EITHER... CONFINED MAINLY TO NEW MEXICO BORDER...OR EAST OF A DOUGLAS TO WILLCOX TO SAFFORD LINE. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. $$ WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS JACKSON KY
206 AM EDT THU APR 26 2012 .UPDATE... ISSUED AT 206 AM EDT THU APR 26 2012 A WARM FRONT IS CURRENTLY ALIGNED ACROSS THE I-64 CORRIDOR...WITH TRAINING CONVECTION ONGOING IN THE FAR NORTHEAST. AN INCREASING LOW LEVEL JET WILL CONTINUE TO FEED MOISTURE ALONG THIS AXIS...WHICH SHOULD SUSTAIN THIS ACTIVITY FOR THE NEXT FEW HOURS. CONVECTION FURTHER SOUTHWEST HAS WANED. AS SUCH...HAVE REALLY TIGHTENED UP THE GRADIENT OF POPS...REDUCING TO SLIGHT CHANCE FOR THE SOUTHWESTERN TWO THIRDS...AND THEN CATEGORICAL ACROSS THE FAR NORTHEAST. LOW TEMPERATURES HAVE LIKELY ALREADY BEEN ESTABLISHED AT MOST LOCATIONS...AND EXPECT A STEADY OR SLOW RISE AT THIS POINT AS SOUTH TO SOUTHWEST WINDS PICK UP. THE COLD FRONT LOOKS TO BE A LITTLE MORE DELAYED TO PASS THROUGH THE AREA ON THURSDAY...WHICH WILL LIKELY RESULT IN A BETTER CHANCE OF CONVECTION RE-FIRING DEPENDING UPON HOW MUCH HEATING OCCURS. WILL WAIT FOR THE NEXT ISSUANCE PACKAGE TO ADDRESS THIS CONCERN. UPDATE ISSUED AT 1015 PM EDT WED APR 25 2012 SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO CROSS ERN KY THIS EVENING. STRONGEST STORMS PRODUCING SOME LIGHTNING AND RADAR ESTIMATED TENTH OF AN INCH OF RAINFALL PER HOUR. STORMS ARE MOVING EAST...100 DEG...AT NEARLY 40 PH SO NO STORM IS PRODUCING HEAVY RAIN FOR ANY GIVEN LOCATION. PARENT LOW IS STILL LOCATED OVER WRN IL WITH A WARM FRONT EXTENDING THRU ERN KY JUST NORTH OF LEX AND JUST SOUTH OF JKL/PIKEVILLE. LOW PRESSURE SHOULD CONTINUE TO TRACK EAST WITH THE WARM FRONT LIFTING TOWARD CVG AND PULLING MUCH OF THE PCPN NORTH OF THE AREA. EXPECTING SRN KY TO SEE LITTLE ADDITIONAL PCPN WHILE NRN KY WILL SEE ADDITIONAL ROUNDS OF SHRA THRU MUCH OF THE NIGHT. SPEED OF THE STORMS WILL LIMIT TOTAL ACCUMULATION. GRIDS HAVE BEEN UPDATED WITH EXPECTED POPS AND TEMPS. ZONES IN GOOD SHAPE WITH NO UPDATE REQUIRED. UPDATE ISSUED AT 757 PM EDT WED APR 25 2012 UPDATED FOR SHRA CROSSING ERN KY. ACTIVITY SHOULD BECOME RATHER PERSISTENT FOR OUR NRN COUNTIES AND SHOULD SEE BREAKS IN THE ACTIVITY FOR THE SWRN THIRD. TEMPS ON TRACK BUT HAVE TWEAKED SLIGHTLY TO ACCOUNT FOR THE EARLIER ONSET OF PCPN. NOT SEEING ANY LIGHTNING AND HAVE DOWNGRADED THE THUNDER CHANCES. MAY NEED TO TAKE THEM OUT COMPLETELY LATER TONIGHT. WILL CONTINUE TO MONITOR. UPDATE ISSUED AT 449 PM EDT WED APR 25 2012 TIMING OF CONVECTION APPROACHING FROM THE WEST AND FURTHER CONVECTION ANTICIPATED LATER THIS EVENING AS WELL AS ASSOCIATED SKY COVER WAS ADJUSTED BASED ON THE LATEST SAT AND RADAR TRENDS. OVERALL...THE 18Z NAM HAS A DECENT HANDLE ON THE APPROACHING CONVECTION...BUT APPEARS TO BE A BIT TOO SLOW. CONVECTION OVER THE NEXT 2 HOURS OR SO SHOULD GENERALLY BE OVER THE SW CWA AND THEN PROBABLY BECOME FOCUS MORE TO THE NE CLOSER TO THE WARM FRONT AND GREATER THETA AND DEWPOINT GRADIENTS AS THE EVENING WEARS ON. CONVECTION THIS EVENING OR EARLY TONIGHT IS STILL CAPABLE OF PRODUCING SOME HAIL OR STRONG WIND GUSTS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 325 PM EDT WED APR 25 2012 A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM. AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL KY. OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD THE CWA FROM LATE ON THU INTO THU NIGHT. THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA. SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA. ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA. IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON. AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 325 PM EDT WED APR 25 2012 MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE WEEKEND AND BEYOND. THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY. HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY. A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH THIS BOUNDARY AROUND OUR REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 206 AM EDT THU APR 26 2012 EXPECT VFR CONDITIONS TO HOLD ACROSS THE TAF SITES THROUGH DAWN...AS CONVECTION HAS ORGANIZED ACROSS FAR NORTHEASTERN KENTUCKY. HAVE INCLUDED A VCTS AT JKL...AS SOME SCATTERED SHOWERS AND THUNDERSTORMS WILL BRUSH BY TO THE NORTH AND EAST THROUGH THE NIGHT. A PASSING COLD FRONT WILL LIKELY RE-FIRE SOME CONVECTION ACROSS THE AREA DURING THE DAY ON THURSDAY...HOWEVER WILL AWAIT FOR LATER GUIDANCE BEFORE TRYING TO NAIL DOWN A BETTER WINDOW OF TIMING. FOR NOW...HAVE INCLUDED VCTS AT ALL LOCATIONS. THE COLD FRONT WILL MOVE THROUGH LATE IN THE AFTERNOON...WITH SOME MVFR OR LOWER POST-FRONTAL STRATOCU ON W TO NW WINDS FOLLOWING. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...JP LONG TERM....KAS AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 AM EDT THU APR 26 2012 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 414 PM EDT WED APR 25 2012 SEVERAL EMBEDDED SHORTWAVES HAVE BEEN MOVING THROUGH THE NW FLOW ACROSS THE UPPER MISS VALLEY AND UPPER GREAT LKS TODAY. WHEN THESE WAVES HAVE INTERACTED WITH THE H925-700 WAA UNDER WEAK SW FLOW...AS SEEN ON RUC ANALYSIS...THEY HAVE PRODUCED AREAS OF LIGHT RAIN SHOWERS OVER NE MN...NW WI AND ALONG THE WI/MI BORDER. WITH THE LLVL DRY AIR IN PLACE OVER MUCH OF UPPER MI AND LITTLE ESE MOVEMENT OF THE SHOWERS...THEY HAVE STRUGGLED TO EFFECT THE AREA. ATTENTION THEN TURNS FARTHER UPSTREAM IN SW ONTARIO WHERE ANOTHER SHORTWAVE AND WEAK WAA HAS BEEN SLOWLY MOVING SE INTO WRN LK SUPERIOR. THIS AREA OF MOISTURE/WAA WILL MERGE WITH SHORTWAVE DROPPING S JUST E OF LK WINNIPEG AND MOVE ACROSS LAKE SUPERIOR TONIGHT. 06 AND 12Z MODEL RUNS REALLY TRENDED THAT DIRECTION AND EARLIER UPDATE TO THE FORECAST WENT WITH THIS IDEA. THINK THESE SHOWERS WILL SLIDE INTO THE WRN PART OF UPPER MI THIS EVENING AND TRY TO SPEED UP AS FRONTAL BOUNDARY ASSOCIATED WITH THE SHORTWAVE PUSHES IT TO THE SE. AS THIS SLIDES ESE ACROSS THE AREA...IT WILL BE INTERACTING WITH THE LINGERING DRY LLVL AIR. MODELS CONSISTENT ON THIS PCPN DIMINISHING SOME AS IT HITS THE DRIER AIR...SO HAVE THE LIKELY POPS OVER THE WRN HALF OF THE CWA AN DIMINISHED TO CHANCES AS IT MOVES INTO THE DRIER AIR. AFTER THE INITIAL PCPN SLIDES THROUGH...COULD HAVE A SECONDARY AREA ASSOCIATED WITH THE SFC-H850 FRONT MOVING THROUGH AFTER 6Z. FORCING ALONG THE FRONT...ALONG WITH THE STRONG SHORTWAVE...SHOULD LEAD TO ANOTHER BAND OF RAIN...POTENTIALLY MIXING WITH OR CHANGING TO SNOW AFFECTING THE NRN HALF OF THE CWA. SOME OF THESE SHOWERS WILL BE ENHANCED IN THE UPSLOPE N FLOW AREAS...WHICH IF IT CHANGES TO ALL SNOW...COULD PRODUCE A LIGHT DUSTING OF SNOW OVER THE WEST AND NCNTRL. EXPECT WINDS TO QUICKLY PICKUP ALONG THIS FRONT AND GUST TO 25-30KTS NEAR LK SUPERIOR LATE TONIGHT AND INTO THURS MORNING. CONSIDERED PUTTING UP A GALE FOR THE ERN HALF OF LK SUPERIOR...AS WINDS RIGHT ALONG THE FRONT WILL GUST TO 35 AND POTENTIALLY 40KTS...BUT SHOULD ONLY BE FOR A BRIEF 1-2HR WINDOW BEFORE DIMINISHING BACK BELOW 35KTS. AS THE FRONT QUICKLY MOVES THROUGH...H850 TEMPS AROUND -9C WILL PROVIDE ENOUGH DELTA-T FOR CLOUDS AS LONG AS MOISTURE REMAINS. SHOULD BE ENOUGH LLVL MOISTURE...AROUND H925-850...TO SUSTAIN CLOUDS NEAR LK SUPERIOR FOR THE FIRST PART OF THE MORNING OVER THE WEST AND INTO THE AFTN OVER THE EAST. DID LEAVE SOME LINGERING -SHSN FOR UPSLOPE LOCATIONS NEAR LK SUPERIOR OVER THE NCNTRL AND EAST...BUT SHOULD DIMINISH FAIRLY QUICKLY WITH THE DRY AIR AND SUBSIDENCE FROM HIGH PRESSURE RIDGE MOVING OVER WRN LK SUPERIOR. IT WILL FEEL MUCH COOLER THAN TODAY OVER MUCH OF THE AREA...BUT ESPECIALLY OVER THE N HALF...AS THE COLD AIR AND WINDS OFF LK SUPERIOR WILL MAKE IT FEEL MUCH COLDER THAT THE LOW-MID 40S HIGHS. IN ADDITION...WITH THE DRY AIR ALOFT AND MIXING WITH THE WINDS WILL LEAD TO FALLING DEWPOINTS FROM WEST TO EAST. RH FALLING TO 25-30 PERCENT OVER THE WEST...BUT FORTUNATELY THE WINDS WILL BE DIMINISHING AND COOLER TEMPS WILL LIMIT FIRE WX CONCERN. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 414 PM EDT WED APR 25 2012 DRY CONDITIONS MAIN THEME OF LONG TERM. VERY LIMITED OPPORTUNITIES FOR RAINFALL IS IN THE FCST THROUGH MONDAY AS HIGH PRESSURE REIGNS OVR THE REGION. INITIALLY WINDS WILL BE OUT OF THE NORTH OR NORTHEAST AS THE HIGH CENTER SETTLES FM NORTHERN MANITOBA AND NINAVUT CANADA ACROSS MUCH OF THE EASTERN CONUS BY EARLY NEXT WEEK. HIGH IS FCST TO PUSH TOWARD EAST CONUS COAST BY TUESDAY ALLOWING SOUTH TO SOUTHWEST RETURN FLOW TO FORM FM THE PLAINS INTO THE WESTERN GREAT LAKES. MOISTURE RETURN INTO GREAT LAKES IS MINIMAL AND DESPITE APPROACH OF A SFC-H85 TROUGH BELIEVE CHANCES OF ANY PRECIPITATION ARE PRETTY SMALL. CONSENSUS OF AVAILABLE MODELS GIVES LOW CHANCE POPS TUESDAY THROUGH WEDNESDAY AS THE TROUGH WORKS THROUGH. LARGE TROUGH RESIDING OVER MUCH OF EASTERN CANADA AND NORTHEAST CONUS WILL KEEP TEMPS GENERALLY AT OR BLO NORMAL THROUGH MUCH OF THE PERIOD...ESPECIALLY NEAR LK SUPERIOR WITH PERSISTENT ONSHORE FLOW. NEAR NORMAL OR POSSIBLY SLIGHTLY ABOVE NORMAL TEMPS MAY OCCUR OVR INTERIOR CNTRL TOWARD WI BORDER AS DEEP MIXING OFFSETS NORTHERLY WINDS. PRIME ISSUE THROUGH THE EXTENDED PERIOD REALLY IS DWPNTS/RH VALUES WITH THE DRY HIGH DOMINATING. CORE OF DRIEST AIR IS OVER THE AREA THURSDAY NIGHT THROUGH MONDAY. LOWERED DWPNTS MORE TOWARD MIXED LAYER DWPNT TOOL OUTPUT FOR AFTN HOURS ON FRIDAY...SATURDAY...AND SUNDAY. SIMILAR TO EARLIER THIS WEEK...GIVEN EXTENT OF DRY AIRMASS OVERHEAD /PWATS 10-20 PCT OF NORMAL/...WOULD NOT BE SHOCKED AT ALL TO SEE AFTN DWPNTS NEAR 0F AND RH VALUES WELL BLO 20 PCT. NNW GRADIENT WINDS STRONGEST ON FRIDAY AFTN OVR EAST HALF...SO THAT IS PROBABLY WHEN FIRE WX ISSUES WOULD BE MAXIMIZED. OTHERWISE...THROUGH THE WEEKEND...WINDS BECOME PRETTY LIGHT AS HIGH PRESSURE RIDGE AXIS IS OVERHEAD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 124 AM EDT THU APR 26 2012 VIGOROUS DISTURBANCE DROPPING SE THRU NRN ONTARIO TOWARD LAKE SUPERIOR WILL DRIVE A COLD FRONT ACROSS THE AREA OVERNIGHT. ALONG/AHEAD OF FRONT...EXPECT SOME -SHRA AT KIWD/KCMX/KSAW WITH CIGS GENERALLY IN THE MVFR RANGE PER UPSTREAM OBS...ALTHOUGH KIWD DID COME IN WITH A 300 FT CIG IN THE PAST HR SO DID ACCOUNT FOR THIS WITH THE 06Z ISSUANCE. ONCE WINDS SHIFT NORTHERLY/INCREASE AFTER FROPA...NOT OUT OF THE QUESTION THAT A PERIOD OF IFR CIGS COULD OCCUR...ESPECIALLY AT KIWD/KSAW SINCE WINDS AT THOSE SITES WILL HAVE A MORE DIRECT UPSLOPE COMPONENT. -SHRA WILL MIX WITH OR CHANGE TO -SHSN LATE IN THE NIGHT AS COLDER AIR SURGES INTO THE AREA...BUT PCPN WILL END EARLY TO MID MORNING AS CLOUD DECK THINS UNDER ADVECTION OF DRIER AIR. CLOUDS SHOULD THEN SCATTER OUT OR CLEAR AT KIWD/KCMX BY LATE MORNING/EARLY AFTN...BUT NOT UNTIL MID AFTN AT KSAW. IN ADDITION...EXPECT GUSTY WINDS BEHIND FRONT OVERNIGHT THRU AT LEAST MID AFTN AS UNSTABLE LOW- LEVELS RESULT IN EFFICIENT MIXING. GUSTS TO 25-30KT WILL BE COMMON AT KCMX/KSAW... ESPECIALLY AT KSAW. WINDS WILL DIMINISH IN THE EVENING UNDER CLEAR SKIES. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 414 PM EDT WED APR 25 2012 LOW PRESSURE OVER IOWA WILL SLIDE SE TONIGHT AND DRAG A SFC TROUGH SE ACROSS LAKE SUPERIOR. STRONG CANADIAN HIGH TRIES TO PUSH IN BEHIND IT AND WILL LEAD TO GUSTY NNW WINDS LATE TONIGHT INTO THURS MORNING. EXPECT A FEW GALE FORCE GUSTS TO 35KTS OVER CNTRL/ERN LK SUPERIOR WITH THIS STRONG GRADIENT. CONSIDERED PUTTING UP A GALE FOR A COUPLE HOUR PERIOD AS THIS BOUNDARY MOVES ACROSS LK SUPERIOR...BUT WITH THE SHORT TIME PERIOD...OPTED TO MENTION THE GUSTS AT THIS TIME. THE CANADIAN HIGH PRESSURE RIDGE WILL THEN MOVE OVER THE UPPER GREAT LKS BY THURS NIGHT DIMINISHING THE WINDS BELOW 20KTS. THIS WILL CONTINUE THROUGH MONDAY...AS THE HIGH MOVES SOUTHEAST ACROSS THE GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 5 AM TO 11 AM EDT THIS MORNING FOR LSZ244-245- 248>250-264>266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...JLA AVIATION...ROLFSON MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1235 AM CDT THU APR 26 2012 .AVIATION...06Z KGRI TAF...CLOUDS WILL THICKEN OVER THE NEXT 24 HOURS AND WINDS WILL INCREASE AND SHIFT SOUTHEASTERLY THROUGH THE DAY ON THURSDAY...WITH VFR CONDS EXPECTED TO HOLD THROUGH THE PERIOD. ALREADY SEEING SIGNIFICANT HIGH CLOUD COVER ADVECTING ACROSS THE LOCAL AREA EARLY THIS MORNING...WITH CIGS EXPECTED TO LOWER GRADUALLY OVER THE NEXT 12-18 HOURS AS AN AREA OF LOW PRESSURE ACROSS THE WEST COAST BEGINS TO LIFT NORTHEASTWARD TOWARDS THE LOCAL AREA. WENT AHEAD A INTRODUCED A VCSH AFT 26/23Z ALONG WITH CIGS AROUND 5KFT...BUT THINK BETTER CHANCE FOR SHOWER AND THUNDERSTORM ACTIVITY LIES JUST BEYOND CURRENT VALID PERIOD OF TAF...AND LEFT OUT PREVAILING PRECIP AND MVFR CIGS AT THIS TIME. EASTERLY WINDS AROUND 8-10KTS ARE EXPECTED TO DEVELOP ACROSS THE LOCAL AREA AROUND DAYBREAK THURSDAY...STEADILY INCREASING AND BECOMING MORE SOUTHEASTERLY AS WE HEAD TOWARDS AFTERNOON HOURS AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN ACROSS THE REGION AHEAD OF THE APPROACHING DISTURBANCE. && .PREV DISCUSSION... /ISSUED 405 PM CDT WED APR 25 2012/ SHORT TERM...THROUGH THURSDAY AFTERNOON. PRIMARY CONCERN IN THE NEXT 24 HOURS IS HOW MUCH OF THE CWA STANDS TO SEE MEASURABLE RAINFALL...AND THE MAIN THEME HERE IS THAT THESE CHANCES CONTINUE TO DECREASE IN MOST AREAS...WITH MUCH BETTER CHANCES HOLDING OFF UNTIL THE THURSDAY NIGHT PERIOD AS DISCUSSED IN THE LONG TERM SECTION BELOW. ALSO...ALL MENTION OF THUNDERSTORMS HAS BEEN PULLED THROUGH THURSDAY AFTERNOON THANKS TO VERY MEAGER INSTABILITY. 19Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK 1000MB LOW OVER CENTRAL IA...WITH A TROUGH AXIS/WEAK COLD FRONT TRAILING SOUTHWESTWARD ACROSS EASTERN/SOUTH CENTRAL KS. IN THE WAKE OF THIS BOUNDARY...NORTH BREEZES GUSTING TO AROUND 30 MPH AND LOCALLY HIGHER HAVE BEEN COMMON ACROSS THE CWA THIS AFTERNOON. DESPITE NEUTRAL TO EVEN WEAK COLD AIR ADVECTION EVIDENT AT 850MB...TEMPS HAVE AGAIN SOARED TO AT LEAST NEAR-RECORD LEVELS IN MANY CENTRAL/SOUTHERN COUNTIES THANKS TO DEEP MIXING INTO THE 750-700MB RANGE PER FORECAST SOUNDINGS. SLIGHTLY COOLER TEMPS HAVE TAKEN HOLD IN THE NORTHWESTERN CWA...RESULTING IN A RANGE FROM LOW-MID 80S NORTHWEST TO MAINLY LOW 90S SOUTHEAST. UNLIKE YESTERDAY..IT APPEARS TRI-CITIES TEMP RECORDS FOR THE DAY ARE LIKELY SAFE. LOOKING ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM A BROAD RIDGE CENTERED OVER THE ROCKIES...WITH AN UPSTREAM TROUGH AND CLOSED 500MB LOW APPROACHING THE SOUTHERN CAL COAST. A SUBTROPICAL MOISTURE PLUME IN THE MID/UPPER LEVELS IS RIDING AROUND THE TOP OF THE RIDGE AND HAS RESULTED IN A FAIRLY THICK BUT NARROW PLUME OF CIRRUS OVERSPREADING MUCH OF THE SOUTHWEST 1/2 OF THE CWA TODAY. MEANWHILE...SOME HIGH BASED CUMULUS AND EVEN SOME WEAK THUNDERSHOWERS ARE POPPING AT THIS HOUR ALONG AN AXIS FROM THE WESTERN NEBRASKA SANDHILLS BACK UP INTO THE BLACK HILLS. LATE THIS AFTERNOON THROUGH AT LEAST MIDNIGHT...THE VAST MAJORITY...IF NOT THE ENTIRE CWA WILL STAY DRY AS THE AIRMASS OVER THE LOCAL AREA IS QUITE CAPPED TO LOW-LEVEL PARCELS. HOWEVER...AM A BIT WARY THAT A LIGHT SHOWER OR MAYBE EVEN A WEAKENING THUNDERSTORM OR TWO COULD TRY MAKING AN RUN AT A FEW OF THE NORTHWEST COUNTIES IN THE 22Z-02Z TIME FRAME...AS ACTIVITY DEVELOPING IN THE VERY STEEP LOW LEVEL LAPSE RATE ENVIRONMENT OFF THE SANDHILLS DRIFTS SOUTHEAST. THIS ACTIVITY IS WELL CAPTURED BY THE LATEST HRRR RUNS...BUT EVEN THIS MODEL...WHICH IS MOST AGGRESSIVE WITH THIS ACTIVITY FADES MOST OF IT OUT BEFORE IT ENTERS THE NORTHWEST COUNTIES. EVENING SHIFT WILL HAVE TO KEEP AN EYE ON THIS...BUT AM GOING TO ONLY GO WITH A SLIGHT CHANCE SPRINKLE MENTION FOR NOW...AND ASSUME THAT ANY HEAVIER SHOWERS OR WEAK THUNDERSTORMS LOSE STEAM BEFORE THEY WOULD GET IN. TURNING TO THE POST-MIDNIGHT HOURS...PULLED THUNDERSTORM MENTION ALTOGETHER...AND EVEN PULLED MEASURABLE POPS...LEAVING ONLY A SLIGHT CHANCE SPRINKLE MENTION IN FAR WESTERN COUNTIES AFTER 08Z. INSTABILITY IS VIRTUALLY NON-EXISTENT LATE TONIGHT...AND THE ONLY FORCING FOR PRECIP WILL BE A GRADUAL MID-LEVEL TOP-DOWN MOISTENING FROM WEST TO EAST EVIDENT IN THE DEWPOINT AND RH FIELD AT 700MB ON MODELS SUCH AS THE 12Z NAM. BETTER CHANCES FOR MEASURABLE LIGHT SHOWERS LATE TONIGHT WILL CERTAINLY RESIDE JUST WEST OF THE CWA OVER THE GLD FORECAST AREA. OTHERWISE...WINDS THIS EVENING WILL QUICKLY DIMINISH...WITH LIGHT FLOW GRADUALLY TURNING FROM NORTHERLY TO EASTERLY AS A SURFACE RIDGE AXIS CENTERED WELL TO THE NORTH MIGRATES EASTWARD. CHANGED LOW TEMPS LITTLE FROM PREVIOUS FORECAST...AND WITH MID LEVEL CLOUDS ON THE INCREASE...WILL KEEP THINGS GENERALLY 2-3 DEGREES ABOVE MET/MAV GUIDANCE CONSENSUS...BOTTOMING OUT MOST OF THE CWA BETWEEN 54-58 DEGREES. ON THURSDAY...THE HEART OF THE MID/UPPER RIDGE AXIS WILL PASS OVERHEAD...AS THE UPSTREAM COMPACT BUT STRONG CLOSED LOW GRADUALLY MIGRATES FROM NEAR THE FAR SOUTHERN TIP OF CAL AT 12Z TO NEAR THE 4-CORNERS BY 00Z. WITH THIS FEATURE REMAINING WELL OFF TO THE SOUTHWEST OF THE CWA...APPRECIABLE FORCING WILL REMAIN WEAK...DESPITE INCREASING MID/HIGH LEVEL CLOUD COVER AND WEAK FORCING ASSOCIATED WITH A SUBTLE LEAD WAVE. THE 12Z NAM WAS QUITE SUPPORTIVE OF PULLING THUNDER MENTION...WITH EVEN ELEVATED CAPE NEGLIGIBLE. HOWEVER...WILL FOLLOW NAM SOLUTION FAIRLY CLOSELY...WITH BEST CHANCE FOR LIGHT SHOWERS FOCUSED ACROSS THE NORTHWEST 1/4 OF THE CWA AS WEAK LIFT FROM THE LEAD SHORTWAVE KEEPS MID LEVEL THETA-E ADVECTION ALIVE. EVEN OUTSIDE THIS MOST FAVORED AREA...KEPT AT LEAST A SLIGHT CHANCE POP OR A SPRINKLE MENTION GOING CWA-WIDE ESPECIALLY DURING THE AFTERNOON...BUT WOULD BE SURPRISED TO SEE MOST AREAS MEASURE MORE THAN A FEW HUNDREDTHS OF AN INCH...AND A GOOD PERCENTAGE OF THE AREA LIKELY STAYING DRY. TEMPS WILL BE A BIT TRICKY...WITH PLENTIFUL CLOUD COVER AND INCREASING EASTERLY WINDS INTO THE 15-20 MPH RANGE DURING THE AFTERNOON. IT WILL CERTAINLY BE COOLER THAN THESE PAST FEW DAYS THOUGH. OPTED TO MAKE LITTLE CHANGE TO PREVIOUS FORECAST...AND DIDN/T STRAY MORE THAN A FEW DEGREES FROM MET/MAV GUIDANCE CONSENSUS...RESULTING IN A RANGE FROM LOW-MID 70S IN NEB ZONES...TO MID-UPPER 70S IN KS ZONES. THESE HIGHS COULD EASILY BE OFF A BIT THOUGH BASED ON CLOUD/PRECIP TRENDS OR LACK THEREOF. LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY. BEGINNING THE MID TERM PERIOD...THE UPPER LEVEL RIDGE WHICH BROUGHT WARM TEMPERATURES AND RECORD HIGHS TO THE PLAINS WILL BEGIN TO BREAK DOWN...MAINLY DUE TO AN UPPER LEVEL TROUGH PUSHING ACROSS THE WEST COAST. AHEAD OF THIS TROUGH...A BURST OF TROUGH ENERGY IN THE FORM OF A SHORT WAVE/CLOSED LOW WILL BEGIN TO SLIDE THROUGH THE PLAINS THURSDAY NIGHT INTO FRIDAY. AS LOW PRESSURE DEVELOPS ALONG THE FRONT RANGE OF THE ROCKIES...AN INCREASED PRESSURE GRADIENT WILL HELP INCREASE EASTERLY WINDS OVERNIGHT THURSDAY. A SURGE OF MOISTURE WILL MOVE INTO THE PLAINS OVERNIGHT...AND COMBINED WITH UPPER LEVEL FORCING AND ISENTROPIC LIFT...CREATE A GOOD CHANCE FOR PRECIPITATION DURING THE OVERNIGHT HOURS ON THURSDAY...ESPECIALLY AFTER MIDNIGHT. THUNDERSTORM CHANCES CERTAINLY REMAIN POSSIBLE ESPECIALLY ACROSS THE SOUTHWEST PORTIONS OF THE FORECAST AREA BEFORE MIDNIGHT AS THE THE DRY LINE MIXES EASTWARD. CANNOT RULE OUT A STRONG TO SEVERE THUNDERSTORM ACROSS THE SOUTHEAST...DEPENDENT UPON WHERE THE DRY LINE SETS UP. AFTER MIDNIGHT AND THROUGH THE DAY ON FRIDAY...BOTH THE GFS AND THE ECMWF SOLUTION KEEP THE SURFACE LOW WELL TO THE SOUTH OF THE FORECAST AREA...THUS KEEPING MUCH OF THE MAIN INSTABILITY AXIS TO THE SOUTH. THE NAM SOLUTION IS A BIT TRICKIER AND KEEPS THE LOW SLIGHTLY FURTHER NORTH. A LARGE AREA OF WRAP AROUND MOISTURE WILL INFILTRATE THE PLAINS...FUELED BY GOOD ISENTROPIC LIFT AND UPPER LEVEL DIFFLUENCE. AT THIS TIME...GIVEN THE DIFFERENCE IN SOLUTIONS...CANNOT RULE OUT ISOLATED THUNDERSTORM CHANCES THROUGH THE DAY ON FRIDAY. THE UPPER LEVEL SHORT WAVE BEGINS TO KICK OFF TO THE EAST BY SATURDAY MORNING...WITH LINGERING POPS ACROSS THE NORTHWEST. SATURDAY LOOKS TO BE PRECIPITATION FREE...WITH PARTLY CLOUDY SKIES. AS A RESULT...DECIDED TO UP TEMPERATURES SLIGHTLY ACROSS THE REGION...WITH MID 60S EXPECTED. THE MAIN UPPER LEVEL LOW FINALLY SHIFTS NORTHWARD BY SUNDAY EVENING. HOWEVER...NUMEROUS MID LEVEL SHORT WAVES CONTINUE TO IMPACT THE PLAINS THROUGH THE LONG TERM PERIOD. SEVERAL SURFACE LOWS DEVELOP ALONG THE FRONT RANGE...PROVIDING SEVERAL CHANCES FOR RAIN SHOWERS THROUGH THE PERIOD. SPECIFICALLY...MONDAY NIGHT THROUGH TUESDAY...AN AREA OF UPPER LEVEL POSITIVE VORTICITY COMBINED WITH SURFACE LOWS WILL BRING A DECENT SHOT OF RAIN SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. INSTABILITY PARAMETERS SUGGEST MUCAPES NEAR 500 J/KG. AT THIS TIME...CANNOT RULE OUT A STRONG THUNDERSTORM OR TWO. WHILE THE WEEKEND WILL BE FAIRLY COOL...WITH HIGHS IN THE UPPER 50S TO LOWER 60S...WARMER TEMPERATURES RETURN TO THE FORECAST AREA BY TUESDAY...WITH LOWER 70S EXPECTED. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS BUFFALO NY
149 AM EDT THU APR 26 2012 .SYNOPSIS... HIGH PRESSURE THAT BROUGHT DRY CONDITIONS AND A FAIR AMOUNT OF SUNSHINE TO THE AREA WILL SLIDE OFF THE EAST COAST TONIGHT. LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL PASS JUST SOUTH OF NEW YORK STATE ON THURSDAY AND BRING A GOOD CHANCE FOR SHOWERS. A NORTHWEST FLOW OF CHILLY AIR WILL FOLLOW ON FRIDAY. && .NEAR TERM /THROUGH TODAY/... A RIDGE OF HIGH PRESSURE WILL SLIDE OFF THE EAST COAST OVERNIGHT AS LOW PRESSURE MOVES EAST FROM IOWA AND REACH THE VICINITY OF CENTRAL OHIO BY 12Z THURSDAY. MID LEVEL CLOUDS WILL INCREASE ACROSS OUR CWA OVERNIGHT AS THIS SYSTEMS APPROACHES. MEANWHILE...LOW CLOUDS HAVE MOVED FURTHER EAST OF LAKE ONTARIO...WHICH WILL ALLOW A PERIOD OF CLEAR SKIES AND LIGHT WINDS. WHILE STILL MARGINAL...DO EXPECT FROST TO DEVELOP IN THIS NARROW WINDOW OF OPPORTUNITY EAST OF LAKE ONTARIO...WITH LOWS AROUND FREEZING. WILL GO WITH A BRIEF FROST ADVISORY FOR OSWEGO/JEFFERSON/LEWIS COUNTIES. THIS SHOULD HAVE A MODEST IMPACT...WITH BRIEF AND NEAR FREEZING TEMPERATURES IMPACTING THE SENSITIVE VEGETATION. ELSEWHERE...HIGH CLOUDS AND AN INCREASING SE FLOW WILL CAUSE TEMPERATURES TO HOLD STEADY...AND EVENTUALLY RISE IN FAR WESTERN SECTIONS TOWARD DAYBREAK. OTHERWISE...RADAR SHOWS THAT SHOWERS ASSOCIATED WITH THE APPROACHING LOW ARE QUITE CONVECTIVE IN NATURE. BOTH MODEL AND RADAR TRENDS SUGGEST A SLIGHTLY SLOWER START TIME...AS SHOWERS CONTINUE TO SLIDE TO THE SE ON A TRAJECTORY TO STAY SOUTH OF THE CWA. 00Z RUNS OF THE NAM/RGEM AND THE LATEST HRRR ARE ALL DOWNPLAYING THE POTENTIAL FOR EARLY MORNING SHOWERS...WITH A MID- TO LATE MORNING TIMING NOW APPEARING MORE LIKELY. SHOWERS WILL EVENTUALLY MOVE INTO THE REGION THURSDAY MORNING. INCREASING LOW LEVEL MOISTURE WILL FOCUS ALONG A SURFACE TROUGH THAT IS FORECAST TO EXTEND NORTH OF THE PARENT LOW. THIS WILL LEAD TO A GOOD CHANCE FOR SHOWERS...ESPECIALLY ACROSS THE NORTH COUNTRY WHERE ADDITIONAL LIFT WILL BE GENERATED BY A POTENT SHORT WAVE AND INCREASING WARM AIR ADVECTION. RIGHT NOW...IT LOOKS LIKE THE STEADIEST PCPN WILL IMPACT WESTERN NEW YORK AND THE GENESEE VALLEY LATE MORNING AND EARLY AFTERNOON...THEN SHIFT INTO THE EASTERN FINGER LAKES AND NORTH COUNTRY DURING THE AFTERNOON HOURS. WHILE THE CHANCES ARE MINIMAL...MODEST LEVELS OF ELEVATED INSTABILITY SUGGEST THERE MAY BE AN ISOLATED RUMBLE OF THUNDER ACROSS THE SOUTHERN TIER ON THURSDAY MORNING. SOUTHERLY WINDS AHEAD OF THE SURFACE TROUGH WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 50S ON THURSDAY...BEFORE COLD AIR ADVECTION SETS UP BEHIND THE TROUGH LATER IN THE AFTERNOON. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW WILL BE IN THE PROCESS OF EXITING THE AREA AT THE START OF THE PERIOD. LOW LEVEL MOISTURE SHOULD REMAIN HIGH IN WAKE OF THE SYSTEM AND THIS COMBINED WITH INCREASING LOW LEVEL COLD AIR ADVECTION WILL CONTINUE THE THREAT FOR SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO DURING THE EVENING. 850 MB TEMPERATURES DROPPING TO BETWEEN -10C AND -12C COULD VERY EASILY BRING SOME LAKE RESPONSE...ESPECIALLY EAST OF LAKE ONTARIO AND THE WESTERN SOUTHERN TIER. BOUNDARY LAYER SHOULD GET COLDER ENOUGH TO SEE A CHANGE OVER TO ALL SNOW OVER THE HIGHER ELEVATIONS. MINOR ACCUMULATIONS IN THE 1 TO 2 INCH RANGE ARE POSSIBLE. SNOW/RAIN SHOWERS WILL LIKELY LINGER FRIDAY MORNING ACROSS EASTERN SECTIONS...BUT WITH SURFACE RIDGING AND ASSOCIATED DRIER AIR BUILDING INTO THE REGION WE WILL SEE AN IMPROVING TREND FOR FRIDAY. STILL PLENTY OF COLD AIR ALOFT WITH 850 MB TEMPERATURES BETWEEN -6C TO -10C...YIELDING DAYTIME HIGHS FRIDAY ONLY IN THE 40S. TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING WILL BE A CONCERN. CLEAR SKIES AND LIGHT WINDS WILL BRING WIDESPREAD FREEZE/FROST CONCERNS. MODEL CONSENSUS CONTINUES TO KEEP THE NORTHERN EDGE OF MOISTURE ALONG AND NORTH OF THE APPROACH WARM FRONT LIFTING UP ACROSS THE OHIO VALLEY TO THE SOUTH OF THE AREA FOR SATURDAY. THE GFS IS THE FARTHER NORTH OF THE SOLUTIONS AND JUST NUDGES THE SOUTHERN TIER WITH SOME VERY MINOR QPF...BUT THE NAM/GEM/ECMWF/SREF SOLUTIONS ALL KEEP HOLD THE PRECIPITATION SOUTH OF THE REGION. AT THIS POINT WILL STAY CLOSE TO MODEL CONSENSUS AND KEEP THE AREA DRY FOR SATURDAY. TEMPERATURES AGAIN SATURDAY NIGHT WILL BE A CONCERN...WITH THE POTENTIAL FOR MORE FREEZE/FROST CONCERNS AS THE HIGH REMAINS PARKED OVER THE REGION. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... LATEST MEDIUM RANGE MODELS AND ENSEMBLES CONTINUING TO SUGGEST THIS PERIOD WILL BE COOL WITH MAINLY QUIET WEATHER. WESTERN AND CENTRAL NEW YORK WILL REMAIN IN A NORTHWESTERLY FLOW REGIME BETWEEN SLOWLY DEPARTING UPPER LOW SPINNING ACROSS EASTERN CANADA AND A SLOWLY PROGRESSIVE RIDGE ACROSS CENTRAL CANADA. AT THE SURFACE...A SPRAWLING AREA OF HIGH PRESSURE WILL SLOWLY BUILD TO THE SOUTHEAST FROM CENTRAL CANADA...SETTLING OVER WESTERN AND CENTRAL NEW YORK DURING THE FIRST HALF OFF THE PERIOD. WARM FRONTAL PRECIPITATION LOOKS TO REMAIN WELL TO THE SOUTH OFF THE AREA DURING THE WEEKEND. THE HIGH REMAINS THE DOMINANT FEATURE TUESDAY...ALTHOUGH SHIFTING EAST OF THE REGION. THIS WILL ALLOW WARM AIR ADVECTION TO SET UP AHEAD OF A FAST MOVING PACIFIC SHORTWAVE WEDNESDAY. WEDNESDAY LOOKS TO HAVE THE BEST THREAT FOR PRECIPITATION AS THIS WAVE WORKS ACROSS THE REGION. BASICALLY...WITH THE CONTINENTAL POLAR AIRMASS REMAINING FIRMLY IN PLACE IN THE SUNDAY THROUGH TUESDAY TIME FRAME. THERE SHOULD BE PLENTY OF SUNSHINE WITH A GRADUAL WARMING TREND. WEDNESDAY LIKELY TO BE THE MILDEST DAY AS WARMER AIR CONTINUES TO SPREAD INTO THE REGION IN A STRENGTHENING RETURN FLOW. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE EXITING ACROSS NEW ENGLAND DURING THE PRE DAWN HOURS WILL KEEP VFR CONDITIONS IN PLACE THROUGH AT LEAST LATE MORNING... ALTHOUGH HIGH CLOUDINESS WILL THICKEN FROM WEST TO EAST. THE ONLY PROBLEM DURING THIS PERIOD WILL BE SOME MARGINAL LOW LEVEL WIND SHEAR CONDITIONS THAT WILL BE FOUND OVER THE WESTERN COUNTIES AS A 35KT SOUTHERLY LOW LEVEL JET WILL BE SET UP BETWEEN 1000-1500 FT. AS THE UPCOMING AFTERNOON PROGRESSES THOUGH...AN AREA OF LOW PRESSURE WILL PASS BY ACROSS PENNSYLVANIA. THIS WILL GENERATE A 3 TO 5 HR PERIOD OF SHOWERS THAT WILL MOVE ACROSS THE REGION WITH CIGS DROPPING TO BETWEEN 2500-3500 FT. AS THE SHOWERS PUSH OFF TO THE EAST THURSDAY EVENING...CIGS SHOULD BE AT MVFR LEVELS WITH WEST TO NORTHWEST WINDS BECOMING GUSTY. OUTLOOK... FRIDAY...MAINLY VFR WITH CHANCE RAIN SATURDAY...MAINLY VFR. SUNDAY AND MONDAY...VFR. && .MARINE... LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL TRACK SOUTH OF NEW YORK STATE THURSDAY...THEN SETTLE OFF THE EAST COAST THURSDAY NIGHT. A BRISK WEST TO NORTHWEST FLOW IN THE WAKE OF THIS LOW WILL LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS THURSDAY NIGHT AND FRIDAY. HIGH PRESSURE WILL BRING QUIETER CONDITIONS SATURDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FROST ADVISORY UNTIL 7 AM EDT THIS MORNING FOR NYZ006>008. MARINE...NONE. && $$ SYNOPSIS...TJP NEAR TERM...APFFEL/TJP SHORT TERM...TMA LONG TERM...TMA AVIATION...RSH MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
209 AM EDT THU APR 26 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE ACROSS THE REGION LATE TONIGHT THROUGH THURSDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES ON FRIDAY. A WARM FRONT WILL DEVELOP JUST SOUTH OF THE REGION ON SATURDAY. && .NEAR TERM /UNTIL NOON TODAY/... HAVE ADJUSTED TEMPERATURES DOWNWARD FOR TONIGHT AS THE RAIN COOLED AIR NOTED BY THE HRRR MODEL MORE ACCURATELY REPRESENTS WHAT IS BEING OBSERVED. THE PREVIOUS RISING TEMPERATURES WITH THE SOUTHWEST WINDS ON THE WARM SIDE OF THE APPROACHING LOW WERE A BIT TOO WARM FOR DAYBREAK TEMPERATURES. I BLENDED IN TOWARDS THE EARLY AFTERNOON FOR TOMORROW AS MIXING WILL DEFINITELY LET THE AIRMASS REACH THE WARMER READINGS WE HAVE IN FOR THIS TIME...ESPECIALLY IN SOUTHERN CWA. NORTHERN CWA WAS A LITTLE COOLER WITH THE OBSERVED TEMPERATURES AND THIS ALSO WORKED WELL WITH THE HRRR READINGS THAT WERE STRONGLY LEANED TOWARDS FOR THE NEXT 12 HOURS OR SO. SOME MODELS WERE LINGERING PRECIP A BIT LONGER INTO THE MORNING HOURS AND SEEING MORE RETURNS COMING IN FROM UPSTREAM I WAS INCLINED TO LINGER LOW CHANCE PROBABILITIES OF SHOWERS THROUGH THE MORNING IN THE EASTERN AND SERN CWA THROUGH ABOUT NOON...BLENDING IN WITH A STRONG CUTOFF TO NO POPS BY THE AFTERNOON HOURS. && .SHORT TERM /NOON TODAY THROUGH 6 PM FRIDAY/... SOME SHOWERS AND THUNDERSTORMS MAY BE ONGOING AT THE BEGINNING OF THE PERIOD. BUT THESE WILL COME TO AN END AS LOW PRESSURE OVER THE AREA MOVES OFF TO THE EAST. MODELS SHOWING QUITE A BIT OF LOW LEVEL MOISTURE LINGERING IN THE WAKE OF THE LOW. SO EXPECT CLOUDS TO PERSIST THROUGH MUCH OF THE DAY. GRADIENT TIGHTENS BEHIND THE LOW RESULTING IN STRENGTHENING WINDS. HOWEVER LOW LEVEL INVERSION SHOULD LIMIT GUSTINESS. HIGH PRESSURE BUILDS IN THURSDAY NIGHT WITH CLEARING. GFS MOS TEMPERATURES LOOKED REASONABLE FOR THE MOST PART. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... CONTINUED MANY OF THE SAME THEMES FROM YESTERDAY/S FORECAST AND DISCUSSION. AT THE BEGINNING OF THE PERIOD /FRIDAY/...VERY AMPLIFIED NRN STREAM CONTINUES WITH A VERY BLOCKY REGIME. SEVERAL PIECES OF SHORTWAVE ENERGY ARE FOCUS...ONE BEING HEIGHT FALLS DIGGING INTO THE PAC NW...THE OTHER BEING A DETERMINED SHORTWAVE ATTEMPTING TO UNDERCUT THE LARGER SCALE BLOCKING RIDGE OFF TO ITS NORTH. THIS WAVE WILL BE NEAR DENVER COLORADO ON FRIDAY MORNING...AND WILL DAMPEN OUT/FLATTEN AS IT MOVES THROUGH THE MEAN RIDGE POSITION ON FRIDAY. BY SATURDAY...NOT MUCH WILL REMAIN AS IT SHEARS INTO THE FLAT/FAST FLOW WHICH IS THE BASE OF THE NERN CONUS LONGWAVE TROUGH. THEREAFTER...UNCERTAINTY INCREASES IN THE PATTERN AS THERE HAS BEEN A MIGRATION AWAY FROM THE MAINTENANCE OF THE NERN CONUS TROUGH...AND VERY SLOW PROGRESSION EASTWARD OF THE HIGH-LATITUDE RIDGE OVER THE NCNTL CONUS. THERE DOES SEEM ENOUGH AGREEMENT/CONFIDENCE TO BEGIN WARMING EARLY NEXT WEEK MORE AGGRESSIVELY. IN THE DETAILS...ISENTROPIC ASCENT/WARM ADVECTION WILL BEGIN WELL ALOFT ON FRIDAY AFTERNOON OVER A VERY DRY BOUNDARY LAYER WHERE DWPTS WILL BE IN THE 20S MOST AREAS. AS FLOW BACKS DOWNSTREAM OF THE DAMPENING WAVE...MOISTURE WILL CONTINUE TO BE TRANSPORTED INTO THE AREA AND THUS EXPECTED HIGH-BASED SHOWERS/AREAS OF RAIN TO STREAK INTO IND/WRN OHIO BY LATE FRI AFTN OR FRI EVENING. A FAIRLY NICE OVERRUNNING EVENT WILL THEN DEVELOP NORTH OF THE TIGHTENING BAROCLINIC ZONE ON SATURDAY AND/OR SATURDAY NIGHT WITH A COLD RAIN AMIDST NELY BOUNDARY LAYER FLOW...ESPECIALLY NRN FORECAST AREA. 25.12Z ECMWF HAS SLOWED A BIT WITH THIS WAVE/FORCING AND NOW PLACES SATURDAY NIGHT AS THE BETTER RAIN CHANCES. THIS IS A CHANCE AND DIFFERENCE FROM PREVIOUS/CONSENSUS RAINS...SO WILL CONTINUE TO FOCUS ON SATURDAY AFTERNOON FOR BEST RAIN CHANCES. TEMPS WILL STRUGGLE MIGHTILY IN THIS REGIME ESP NORTH OF I-70 TO GET MUCH ABOVE THE MID 40S. THE VERY TIGHT THERMAL GRADIENT /70S OVER CNTL KY/ WILL INDUCE INSTABILITY AND LOW CONFIDENCE TEMP FORECAST ALONG/SOUTH OF OHIO RIVER WHERE HIGHS IN THE 50S JUST AS POSSIBLE AS HIGHS IN THE 70S DEPENDING ON WHERE FRONT SETS UP. AND THERE IS SLUG OF ELEVATED CAPE ACROSS SRN FORECAST AREA SO CONTINUED THREAT OF STORMS IN THE SOUTH ON SATURDAY. EXPECT AS THIS WAVE SHIFTS THROUGH QUICKLY SAT NIGHT PRECIP ENDING FROM NORTH TO SOUTH...AND SUNDAY TO BE DRY/COOL WITH AGAIN ANOTHER INTRUSION OF NELY FLOW AND LOW DEWPOINTS. KEEPING THE FORECAST DRY THROUGH MONDAY WITH SLOW WARMING. REMNANTS OF THE PAC NW/SWRN CANADA HEIGHT FALLS FINALLY SLIDE INTO THE GREAT LAKES TUESDAY/WEDNESDAY WITH THREAT OF STORMS. DID NOT WARM AS AGGRESSIVELY AS ECMWF/GFS MOS GUIDANCE BUT DID TURN IT AROUND A LITTLE MORE QUICKLY FROM PREVIOUS FORECAST. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... INITIAL BATCH OF CONVECTION HAS PUSHED THRU THE TAFS. ANOTHER PATCH IS TRYING TO DEVELOP ALONG AND E OF I-75 ALONG A CONVERGENCE BOUNDARY. THESE SHRA ARE EXPECTED TO MAINLY AFFECT CMH/LCK OVER THE NEXT HOUR OR TWO. EXCEPT FOR CMH/LCK...BACKED OFF ON THE MVFR CIGS FOR THE MOMENT. AS SURFACE LOW APPROACHES LATER THIS MORNING...EXPECT IT BRING THE MVFR CIGS TO ALL THE TAFS. LOW AND CDFNT WILL CROSS THE TAFS FROM 10-12Z. WINDS WILL TURN TO THE NORTHWEST AND INCREASE TO 10 TO 15 KT...GUSTING AS HIGH AS 25KT. REMNANT LOW LEVEL MOISTURE WILL KEEP MVFR CLOUDS ACROSS THE AREA FOR MUCH OF THE DAY. MVFR CIGS SHOULD DISSIPATE QUICKLY AROUND 00Z AS HIGH PRESSURE BUILDS IN FROM THE NW. OUTLOOK...SHOWERS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY NIGHT THROUGH SATURDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS... NEAR TERM...FRANKS SHORT TERM... LONG TERM...BINAU AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1229 AM EDT THU APR 26 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE ACROSS THE REGION LATE TONIGHT THROUGH THURSDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES ON FRIDAY. A WARM FRONT WILL DEVELOP JUST SOUTH OF THE REGION ON SATURDAY. && .NEAR TERM /UNTIL NOON TODAY/... HAVE ADJUSTED TEMPERATURES DOWNWARD FOR TONIGHT AS THE RAIN COOLED AIR NOTED BY THE HRRR MODEL MORE ACCURATELY REPRESENTS WHAT IS BEING OBSERVED. THE PREVIOUS RISING TEMPERATURES WITH THE SOUTHWEST WINDS ON THE WARM SIDE OF THE APPROACHING LOW WERE A BIT TOO WARM FOR DAYBREAK TEMPERATURES. I BLENDED IN TOWARDS THE EARLY AFTERNOON FOR TOMORROW AS MIXING WILL DEFINITELY LET THE AIRMASS REACH THE WARMER READINGS WE HAVE IN FOR THIS TIME...ESPECIALLY IN SOUTHERN CWA. NORTHERN CWA WAS A LITTLE COOLER WITH THE OBSERVED TEMPERATURES AND THIS ALSO WORKED WELL WITH THE HRRR READINGS THAT WERE STRONGLY LEANED TOWARDS FOR THE NEXT 12 HOURS OR SO. SOME MODELS WERE LINGERING PRECIP A BIT LONGER INTO THE MORNING HOURS AND SEEING MORE RETURNS COMING IN FROM UPSTREAM I WAS INCLINED TO LINGER LOW CHANCE PROBABILITIES OF SHOWERS THROUGH THE MORNING IN THE EASTERN AND SERN CWA THROUGH ABOUT NOON...BLENDING IN WITH A STRONG CUTOFF TO NO POPS BY THE AFTERNOON HOURS. && .SHORT TERM /NOON TODAY THROUGH 6 PM FRIDAY/... SOME SHOWERS AND THUNDERSTORMS MAY BE ONGOING AT THE BEGINNING OF THE PERIOD. BUT THESE WILL COME TO AN END AS LOW PRESSURE OVER THE AREA MOVES OFF TO THE EAST. MODELS SHOWING QUITE A BIT OF LOW LEVEL MOISTURE LINGERING IN THE WAKE OF THE LOW. SO EXPECT CLOUDS TO PERSIST THROUGH MUCH OF THE DAY. GRADIENT TIGHTENS BEHIND THE LOW RESULTING IN STRENGTHENING WINDS. HOWEVER LOW LEVEL INVERSION SHOULD LIMIT GUSTINESS. HIGH PRESSURE BUILDS IN THURSDAY NIGHT WITH CLEARING. GFS MOS TEMPERATURES LOOKED REASONABLE FOR THE MOST PART. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... CONTINUED MANY OF THE SAME THEMES FROM YESTERDAY/S FORECAST AND DISCUSSION. AT THE BEGINNING OF THE PERIOD /FRIDAY/...VERY AMPLIFIED NRN STREAM CONTINUES WITH A VERY BLOCKY REGIME. SEVERAL PIECES OF SHORTWAVE ENERGY ARE FOCUS...ONE BEING HEIGHT FALLS DIGGING INTO THE PAC NW...THE OTHER BEING A DETERMINED SHORTWAVE ATTEMPTING TO UNDERCUT THE LARGER SCALE BLOCKING RIDGE OFF TO ITS NORTH. THIS WAVE WILL BE NEAR DENVER COLORADO ON FRIDAY MORNING...AND WILL DAMPEN OUT/FLATTEN AS IT MOVES THROUGH THE MEAN RIDGE POSITION ON FRIDAY. BY SATURDAY...NOT MUCH WILL REMAIN AS IT SHEARS INTO THE FLAT/FAST FLOW WHICH IS THE BASE OF THE NERN CONUS LONGWAVE TROUGH. THEREAFTER...UNCERTAINTY INCREASES IN THE PATTERN AS THERE HAS BEEN A MIGRATION AWAY FROM THE MAINTENANCE OF THE NERN CONUS TROUGH...AND VERY SLOW PROGRESSION EASTWARD OF THE HIGH-LATITUDE RIDGE OVER THE NCNTL CONUS. THERE DOES SEEM ENOUGH AGREEMENT/CONFIDENCE TO BEGIN WARMING EARLY NEXT WEEK MORE AGGRESSIVELY. IN THE DETAILS...ISENTROPIC ASCENT/WARM ADVECTION WILL BEGIN WELL ALOFT ON FRIDAY AFTERNOON OVER A VERY DRY BOUNDARY LAYER WHERE DWPTS WILL BE IN THE 20S MOST AREAS. AS FLOW BACKS DOWNSTREAM OF THE DAMPENING WAVE...MOISTURE WILL CONTINUE TO BE TRANSPORTED INTO THE AREA AND THUS EXPECTED HIGH-BASED SHOWERS/AREAS OF RAIN TO STREAK INTO IND/WRN OHIO BY LATE FRI AFTN OR FRI EVENING. A FAIRLY NICE OVERRUNNING EVENT WILL THEN DEVELOP NORTH OF THE TIGHTENING BAROCLINIC ZONE ON SATURDAY AND/OR SATURDAY NIGHT WITH A COLD RAIN AMIDST NELY BOUNDARY LAYER FLOW...ESPECIALLY NRN FORECAST AREA. 25.12Z ECMWF HAS SLOWED A BIT WITH THIS WAVE/FORCING AND NOW PLACES SATURDAY NIGHT AS THE BETTER RAIN CHANCES. THIS IS A CHANCE AND DIFFERENCE FROM PREVIOUS/CONSENSUS RAINS...SO WILL CONTINUE TO FOCUS ON SATURDAY AFTERNOON FOR BEST RAIN CHANCES. TEMPS WILL STRUGGLE MIGHTILY IN THIS REGIME ESP NORTH OF I-70 TO GET MUCH ABOVE THE MID 40S. THE VERY TIGHT THERMAL GRADIENT /70S OVER CNTL KY/ WILL INDUCE INSTABILITY AND LOW CONFIDENCE TEMP FORECAST ALONG/SOUTH OF OHIO RIVER WHERE HIGHS IN THE 50S JUST AS POSSIBLE AS HIGHS IN THE 70S DEPENDING ON WHERE FRONT SETS UP. AND THERE IS SLUG OF ELEVATED CAPE ACROSS SRN FORECAST AREA SO CONTINUED THREAT OF STORMS IN THE SOUTH ON SATURDAY. EXPECT AS THIS WAVE SHIFTS THROUGH QUICKLY SAT NIGHT PRECIP ENDING FROM NORTH TO SOUTH...AND SUNDAY TO BE DRY/COOL WITH AGAIN ANOTHER INTRUSION OF NELY FLOW AND LOW DEWPOINTS. KEEPING THE FORECAST DRY THROUGH MONDAY WITH SLOW WARMING. REMNANTS OF THE PAC NW/SWRN CANADA HEIGHT FALLS FINALLY SLIDE INTO THE GREAT LAKES TUESDAY/WEDNESDAY WITH THREAT OF STORMS. DID NOT WARM AS AGGRESSIVELY AS ECMWF/GFS MOS GUIDANCE BUT DID TURN IT AROUND A LITTLE MORE QUICKLY FROM PREVIOUS FORECAST. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... A SURFACE LOW DEVELOPING AND PUSHING EAST ACROSS OUR AREA TONIGHT WILL COMBINE WITH A WARM FRONT OVER OUR TO PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS. MOST OF THE ACTIVITY IS EXPECTED TO OCCUR BETWEEN 01Z AND 07Z TONIGHT ACROSS OUR TAF TERMINALS. MAINLY MVFR...WITH ISOLATED IFR CONDITIONS WILL OCCUR IN HEAVIER STORMS. AFTER 07Z...THE FOCUS OF THE HEAVIER ACTIVITY WILL SHIFT SOUTHEAST OF THE TAF TERMINALS. AS THE SURFACE LOW MOVES OVER OUR AREA LATE TONIGHT...CIGS WILL LOWER TO MVFR WITH SCATTERED SHOWERS MOVING THROUGH THE AREA. AFTER SUNRISE...SHOWERS WILL COME TO AN END ACROSS THE AREA. AROUND THAT TIME...A COLD FRONT WILL PUSH SOUTHEASTWARD ACROSS THE THE TERMINALS. THIS WILL CAUSE WINDS WILL VEER TO THE NORTHWEST AND INCREASE TO 10 TO 15 KT...GUSTING AS HIGH AS 25KT. REMNANT LOW LEVEL MOISTURE WILL KEEP MVFR CLOUDS ACROSS THE AREA FOR MUCH OF THE DAY. OUTLOOK...SHOWERS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY NIGHT THROUGH SATURDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS... NEAR TERM...FRANKS SHORT TERM... LONG TERM...BINAU AVIATION...LATTO
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1156 PM CDT WED APR 25 2012 .UPDATE...FOR 06Z AVIATION DISCUSSION. && .AVIATION...FOR 06Z AVIATION DISCUSSION. PROGRESSIVE WRLY LLJ STRUCTURE WILL RESULT IN LLWS AT TAF SITES AROUND 26/06Z-26/08Z. WITH NO NOTICEABLE SHWRS/TSTMS TO OUR NW... WILL NOT MENTION SHWRS/TSTMS UNTIL AFTER 26/15Z. WITH THE COLD FRONT SAGGING SWD INTO MID STATE BY 26/18Z...PROVIDING A FOCUSING MECHANISM FOR SCT SHWRS/TSTMS...WITH LOCATION UNCERTAINTY... THRU 27/02Z...WHEN DIURNAL INFLUENCES WEAKEN AND SHWRS DISSIPATE. && .PREV DISCUSSION.../ISSUED 929 PM CDT WED APR 25 2012/ UPDATE... LATEST WRF AND RUC SOLUTIONS NOT SHOWING MUCH IN THE WAY OF REDEVELOPMENT ACROSS OUR SOUTHWESTERN COUNTIES. THE 18Z GFS RUN DOES SHOW AN AREA OF CONVECTION MOVING ACROSS MUCH OF THE WESTERN PORTIONS OF THE MID STATE AFTER 06Z. HOWEVER...THIS ACTIVITY IS IN THE FORM OF AN MCS WHICH IS EXPECTED TO MOVE SOUTHEAST FROM MO. LATEST RADAR IMAGERY IS NOT SHOWING MUCH IN THE WAY OF DEVELOPMENT THERE. THEREFORE...WILL LOWER POPS...PARTICULARLY ACROSS SOUTHEASTERN ZONES. REMAINDER OF FCST LOOKS OK. .PREV DISCUSSION.../ISSUED 656 PM CDT WED APR 25 2012/ UPDATE...FOR 00Z AVIATION DISCUSSION. AVIATION...00Z AVIATION DISCUSSION. WILL MENTION VCSH THRU 26/13Z PER CONFIDENCE IN OCCURRENCE/BUT LOCATION UNCERTAINTY. PROGRESSIVE WRLY LLJ STRUCTURE WILL RESULT IN LLWS AT TAF SITES AROUND 26/06Z-26/11Z. WITH SHORTWAVE EXPECTED TO MOVE INTO MID STATE AFTER 26/06Z...WILL NOT MENTION TSRA UNTIL 26/06Z-26/10Z. BELIEVE ACTIVITY WILL WEAKEN BY 26/13Z WITH IFR CEILING PREDOMINATE. CEILINGS SHOULD LIFT INTO THE MVFR RANGE BY 26/15Z-26/16Z WITH A COLD FRONT SAGGING SWD INTO MID STATE BY 26/18Z...PROVIDING A FOCUSING MECHANISM FOR SCT SHWRS/TSTMS...WITH LOCATION UNCERTAINTY...THRU 26/24Z. PREV DISCUSSION.../ISSUED 606 PM CDT WED APR 25 2012/ UPDATE... FRONTAL BOUNDARY LOCATED WELL TO THE NW OF MIDDLE TN AND IS LOCATED ACROSS NORTHERN MO AND SW THROUGH SRN KN. SHORTWAVE IMPULSES AND NOT EXPECTED TO ARRIVE UNTIL LATE TONIGHT. THUS...WITH A RATHER INACTIVE RADAR RIGHT NOW...WILL OPT TO ADJUST THE ONE WORDING TO REFLECT AFT MIDNIGHT WORDING. THROUGH THIS EVENING THE ACTIVITY LOOKS ISOLATED TO SCT AT BEST. OTW...REMAINDER OF FCST APPEARS TO BE IN GOOD SHAPE. DEW POINTS ACROSS THE AREA ARE IN THE LOWER 60S WHICH IS THE FCST LOW. SOUTHERLY WIND FLOW OF 5-15 MPH EXPECTED TO CONTINUE OVERNIGHT. WILL MAKE GRID ADJUSTMENTS TO INCREASE CLOUD COVERAGE ACROSS THE SOUTH. ALSO...WILL INCLUDE A 6HR SPLIT OF THE WEATHER GRIDS. UPDATE OUT SHORTLY. PREV DISCUSSION.../ISSUED 243 PM CDT WED APR 25 2012/ DISCUSSION... WARM FRONT HAS LIFTED NORTH AND INTO KENTUCKY AT MID AFTERNOON. A FEW SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED ALONG AND SOUTH OF WARM FRONTAL BOUNDARY AND IN WESTERN KENTUCKY AND WESTERN TENNESSEE THIS AFTERNOON. THIS HAS BEEN MAINLY WARM ADVECTION TYPE SHOWERS AND STORMS. SURFACE TEMPS HAVE WARMED INTO THE 70S AT MANY LOCATIONS WITH 83 AT NASHVILLE. MOISTURE IS INCREASING IN THE LOWER LEVELS THIS AFTERNOON BUT SLOWLY WITH DEWPOINT TEMPS CURRENTLY MOSTLY IN THE 50S. AS UPPER LEVEL FLOW CONTINUES OUT OF THE NORTHWEST TONIGHT MID STATE WILL BE IN WARM SECTOR WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS. BELIEVE A BETTER CHANCE WILL COME TOWARD MIDNIGHT NEAR KENTUCKY BORDER AND EXPECT THIS ACTIVITY TO SINK SOUTHWARD DURING THE LATE NIGHT. THIS IS DUE IN PART TO A SHORT WAVE THAT WILL BE DROPPING SOUTHEAST EMBEDDED IN NORTHWEST FLOW ALOFT. A WEAK COOL FRONT WILL ALSO APPROACH FROM THE NORTHWEST AND EXTEND ALONG THE OHIO RIVER BACK DOWN THROUGH SOUTHEAST MISSOURI AROUND 12Z THURSDAY. THINK BEST SEVERE THREAT WILL BE ACROSS OHIO VALLEY TONIGHT. COULD SEE AN MCS DEVELOP THIS EVENING OVER CENTRAL AND SOUTHERN ILLINOIS SO WILL KEEP AN EYE OUT TO THE NORTHWEST. COOL FRONT PULLS UP ALONG TENNESSEE/KENTUCKY BORDER ON THURSDAY THEN LIFTS BACK NORTH LATE IN THE DAY AS A WARM FRONT. SO EXPECT TO SEE SCATTERED SHOWERS AND STORMS ON THURSDAY. IN FACT IT LOOKS LIKE AN UNSETTLED PERIOD COMING UP FOR THE NEXT SEVERAL DAYS WITH SHOWER AND STORM CHANCES. LOOKS LIKE TEMPS WILL AVERAGE ABOVE CLIMATOLOGY FOR THE NEXT SEVEN DAYS. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
355 AM CDT THU APR 26 2012 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT 355 AM CDT THU APR 26 2012 MAIN FORECAST CONCERNS THIS PACKAGE...LOWS AND FROST THREAT LATE TONIGHT...RAIN CHANCES FRI THROUGH SAT NIGHT...SNOW POSSIBILITY LATE FRI NIGHT/SAT MORNING. 06Z DATA ANALYSIS HAD LOW PRESSURE OVER CENTRAL IL AND A BROAD AREA OF HIGH PRESSURE BUILDING SOUTH OUT OF NORTHERN MAN/SASKAT. WIND FIELD ACROSS MN/WI INDICATED A FRONTAL BOUNDARY ON THE LEADING EDGE OF THE HIGH FROM NORTH-CENTRAL WI TO FAR NORTHWEST IA...WITH LIGHT/ VARIABLE WINDS SOUTH OF THE BOUNDARY AND NORTH/NORTHWEST WINDS GUSTING UP TO 20 KTS BEHIND THE BOUNDARY. LITTLE TEMP DIFFERENCE ACROSS THE BOUNDARY...BUT MORE NORTH/NORTHEAST LOW LEVEL FLOW BEHIND IT WERE ADVECTING STRATUS CLOUDS SOUTH ACROSS EASTERN MN/NORTHERN WI. WIDE RANGE OF TEMPS ACROSS THE REGION THIS MORNING...AROUND 40 NEAR LK SUPERIOR TO MID 60S IN PARTS OF CENTRAL IA. NO BIG ERRORS NOTED WITH 26.00Z MODEL INITIALIZATIONS...HOWEVER GFS IS AGAIN SOME 5F TO 8F TOO HIGH WITH SFC DEW POINT OVER THE MID MS VALLEY INTO THE SOUTHERN PLAINS. SOLUTIONS SIMILAR THRU TONIGHT THEN DIVERGE WITH TIMING OF THE RAIN SPREADING INTO THE AREA FRI THEN OUT OF THE AREA SAT/SAT NIGHT. DPROG/DT OF 500MB HGTS AT 26.00Z SHOWED MODEL RUNS OF 24.00Z AND 25.00Z VERIFIED WELL ACROSS NOAM AND OFF THE BC/OR/WA COAST BUT THE TREND WAS SLOWER WITH THE TROUGHING APPROACHING SOUTHERN CA. MODELS COMING INTO BETTER/TIGHTER CONSENSUS WITH THE SOUTHERN CA TROUGHING INTO CO/KS BY FRI MORNING...FAVORING SLOWER OF THE EARLIER RUNS. TREND WAS SLOWER WITH THE EASTERN CONUS TROUGH AS WELL. TREND THRU FRI/FRI NIGHT IS FOR MORE TROUGHING OVER THE CENTRAL/NORTHERN ROCKIES WITH THE CO/KS ENERGY EJECTING FURTHER NORTH INTO THE MID/UPPER MS VALLEY BY SAT MORNING. IMPROVING CONSENSUS TROUGHING OVER THE NORTHEAST CONUS AND ROCKIES AND RIDGING OVER THE MID/UPPER MS VALLEY INTO MAN/WESTERN ONT. WITH THE SHIFTS BY FRI NIGHT...RUN-TO-RUN CONSISTENCY TAKES A HIT FOR FRI NIGHT THRU SAT NIGHT. CHECK OF OBS VS. MODEL DATA AT 06Z SHOWED ALL QUITE GOOD WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS...HOWEVER ALL STRUGGLING A BIT WITH THE CLOUDS/MOISTURE SPREADING SOUTH ACROSS MN/WI EARLY THIS MORNING. PER WV IMAGERY GFS/GEM/ECMWF LOOKED BETTER WITH THE SHORTWAVE DETAILS ALONG/OFF THE WEST COAST. NO CLEAR MODEL FAVORITE AGAIN AND WITH THE TREND TOWARD A TIGHTER CONSENSUS THRU SAT NIGHT...FAVORED THE CONSENSUS. SHORT-TERM FCST CONFIDENCE GOOD THRU TONIGHT...THEN AVERAGE FRI THRU SAT NIGHT WITH THE PRECIP TIMING/LOCATION DIFFERENCES THAT APPEAR AMONG THE MODELS. IN THE SHORT TERM...COOLER CAN HIGH PRESSURE WILL CONTINUE TO BUILD SOUTH INTO THE UPPER MIDWEST TODAY. CLOUDS TO OUR NORTH WILL BE PROBLEMATIC THIS MORNING BUT ALL MODELS INDICATE STRONGER 925-850MB COLD ADVECTION/SUBSIDENCE/DRYING...LOW LEVEL ANTICYCLONIC FLOW AND STEEP LOW LEVEL LAPSE RATES WILL ERODE/MIX OUT THE CLOUDS DURING THE LATE MORNING/EARLY AFTERNOON. 925MB TEMPS IN THE +4C TO +8C RANGE BY 00Z FRI...FOR A MUCH COOLER DAY OVER PORTIONS OF THE FCST AREA AS THE HIGH BUILDS IN. STILL QUESTIONS ABOUT LOWS TONIGHT AND FROST POTENTIAL OVER THE NORTHEAST 1/3 OF THE FCST AREA. GOOD CONSENSUS FOR THE SFC RIDGE AXIS TO BUILD INTO EASTERN WI/LK MI BY 12Z FRI. THIS WOULD ALLOW FOR A BIT MORE GRADIENT WIND ACROSS THE FCST AREA THRU TONIGHT FOR BOUNDARY LAYER MIXING. MODELS ALL CONTINUE TO INDICATE AN INCREASE OF HIGH LEVEL MOISTURE/CLOUDS OVER THE AREA LATER TONIGHT AS MOISTURE AHEAD OF THE TROUGHING INTO CO/KS BY FRI MORNING STREAMS INTO THE RIGHT ENTRANCE REGION OF A 120KT JET MAX OVER THE GREAT LAKES. THIS WOULD LIMIT RADIATIONAL COOLING LATER TONIGHT. LEFT PATCHY TO AREAS OF FROST IN THE GRIDS BETWEEN 05-13Z FRI BUT WILL HOLD OFF ON ANY POSSIBLE FROST HEADLINES AND LET DAY CREW HAVE ANOTHER SET OF MODELS AND 12HRS OF OBS TO EVALUATE. STRENGTHENING WARM ADVECTION/ISENTROPIC LIFT IN THE 700-500MB LAYER ALONG WITH DEEPENING MOISTURE SPREAD INTO THE WEST END OF THE FCST AREA LATE TONIGHT...UNDER THE RIGHT ENTRANCE REGION OF THE GREAT LAKES JET MAX. BROAD ASCENT/SATURATION INDICATED IN THE 700-300MB LAYER...WITH THE SFC-800MB LAYER REMAINING ON THE DRY SIDE...MUCH LIKE LATE TUE NIGHT/WED MORNING WERE. CONTINUED A SMALL -SHRA CHANCE OVER THE WEST END OF THE FCST LATE TONIGHT. MOISTURE/LIFT CONTINUE TO SLOWLY INCREASE AND SPREAD NORTHEAST INTO THE FCST AREA FRI/FRI NIGHT. STRONGEST/DEEPEST OF THIS REMAINS OVER THE CENTRAL/SOUTHWEST PARTS OF THE FCST AREA FRI/FRI NIGHT AND INTO SAT. WITH THE SHIFT OF THE MODEL CONSENSUS NORTHWARD WITH THE FORCING/MOISTURE AND A BROAD BAND OF RA/SHRA...GRADUALLY RAISED RAIN CHANCES OVER THE SOUTHWEST 2/3 OF THE FCST AREA THRU FRI THEN RAISED THESE TO 60-80 PERCENT THESE AREAS FRI NIGHT. WITH THE DRIER SFC-800MB AIRMASS...MODEL SOUNDINGS INDICATE LOWER LEVEL EVAPORATIVE COOLING MAY ALLOW FOR A MIX OF -RA/-SN OR SOME WET SNOW LATE TONIGHT INTO SAT MORNING ACROSS MUCH OF THE FCST AREA. HOWEVER...THERE MAY BE ISSUES WITH ICE INTRODUCTION INTO THE TOPS OF THE CLOUDS. SOUNDINGS SHOWING CLOUD TOP TEMPS MAY BE AT OR WARMER THAN -10C AT 12Z SAT...WITH LITTLE OR NO ICE IN THE CLOUDS AND PRECIP FALLING AS A COLD RAIN. DID LEAVE A -RA/-SN MIX IN FCST GRIDS FOR LATE FRI NIGHT THRU 15Z SAT FOR THE POSSIBILITY OF SOME SNOWFLAKES. ALL MODELS BUT GFS INDICATE WEAK CONVERGENCE AND MOISTURE IN THE SFC-700MB TROUGH AXIS REMAIN OVER THE AREA ON SAT...WITH SOME THIS LINGERING/CONTINUING TO WEAKEN OVER THE AREA SAT NIGHT. RAISED PRECIP CHANCES INTO THE 25-65 PERCENT RANGE /HIGHEST OVER THE SOUTHWEST 2/3 OF THE FCST AREA/ SAT AND LINGERED A SMALL -RA CHANCE SAT NIGHT. GENERALLY FAVORED A BLEND OF THE NUMERICAL GUIDANCE HIGHS/LOWS FOR TONIGHT THRU SAT NIGHT. .LONG TERM...SUNDAY THROUGH WEDNESDAY 355 AM CDT THU APR 26 2012 26.00Z MEDIUM RANGE MODELS IN GENERALLY GOOD AGREEMENT FOR SUN THRU WED AS THE NORTHERN ROCKIES TROUGHING EVENTUALLY PROGRESSES EAST ACROSS THE AREA MON...THEN WITH AN ACTIVE QUASI-ZONAL FLOW FLOW ACROSS THE NORTHERN CONUS IN TO THE MIDDLE OF NEXT WEEK. APPEARS BEST CHANCE FOR A DRY DAY IN THE DAY 4-7 PERIOD WILL BE SUN WITH SHORTWAVE RIDGING ALOFT AND SFC HIGH PRESSURE OVER THE REGION. FALLING HGTS ALOFT WITH THE TROUGH AND PIECES OF SHORTWAVE ENERGY ROTATING THRU THE FLOW WILL BRING PERIODIC ROUNDS OF DEEPER FORCING/LIFT ACROSS THE AREA IN THE MON-WED PERIOD. PLENTY OF MODEL DETAIL/TIMING DIFFERENCES WITH THESE SHORTWAVE FEATURES AND LOWER LEVEL MOISTURE/THERMO-DYNAMIC FORCING PARAMETERS BY MON-WED. WITH SFC LOWS PASSING NORTH OF THE AREA TUE/WED AND DEEP SOUTH/SOUTHWEST FLOW TAPPING INTO SOME GULF MOISTURE...INSTABILITY LOOKS TO INCREASE OVER THE AREA FOR TUE/WED. AFTER A SHRA CHANCE MON ADDED MORE TSRA TO THE FCST GRIDS FOR TUE/WED. TEMPS TO WARM THRU THE LONG TERM PERIOD WITH RATHER PERSISTENT SOUTH/SOUTHWEST FLOW...BELOW NORMAL SUN TO ABOVE NORMAL BY TUE/WED. MODEL/ENSEMBLE CONSENSUS DATA IN THE DAY 4-7 FCST GRIDS HAS THIS WELL TRENDED FOR NOW. && .AVIATION...THROUGH 06Z FRIDAY 1148 PM CDT WED APR 25 2012 A TROUGH OF LOW PRESSURE EXTENDS INTO CENTRAL MINNESOTA FROM AN AREA OF LOW PRESSURE OVER WEST CENTRAL ILLINOIS. HIGH PRESSURE WAS OVER CENTRAL CANADA WITH THE RIDGE AXIS EXTENDING SOUTH INTO NORTH DAKOTA. ENOUGH OF A CYCLONIC FLOW EXISTS BETWEEN THESE TWO FEATURES TO CONTINUE TO PRODUCE SOME CLOUDS OVER NORTHEAST MINNESOTA INTO NORTHERN WISCONSIN. THESE CLOUDS HAVE BEEN TRYING TO WORK SOUTH TOWARD THE AREA BUT AS THEY DUE THEY BECOME SCATTERED AND THEN DISSIPATE. THROUGH THE NIGHT...THE CYCLONIC FLOW SHOULD GRADUALLY SLIP SOUTH INTO THE AREA ALLOWING SOME OF THESE CLOUDS TO GET INTO THE AREA. BOTH THE 26.00Z NAM AND 26.02Z RUC WANT TO BRING IN A BROKEN MVFR TO VFR DECK FOR THE OVERNIGHT HOURS...BUT THIS LOOKS OVER DONE BASED ON CURRENT SATELLITE TRENDS AND OBSERVATIONS. WILL ONLY BRING IN SOME SCATTERED CLOUDS AND IF A CEILING DOES DEVELOP WOULD EXPECT IT TO BE VFR. STEEP LOW LEVEL LAPSE RATES ARE ALSO EXPECTED TO DEVELOP LATE TONIGHT AND PERSIST INTO THURSDAY AFTERNOON ALLOWING SOME GUSTY NORTH WINDS TO DEVELOP AT BOTH SITES. EXPECT THE GUSTS TO BE IN THE 20 TO 25 KNOT RANGE UNTIL THE SURFACE RIDGE BUILDS IN ENOUGH THURSDAY AFTERNOON TO ALLOW THE WINDS TO SETTLE DOWN. && .ARX WATCHES/WARNINGS/ADVISORIES... 355 AM CDT THU APR 26 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RRS LONG TERM....RRS AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT WED APR 25 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY 338 PM CDT WED APR 25 2012 AT 3 PM...A SURFACE LOW WAS LOCATED JUST WEST OF CHARLES CITY IOWA. A WARM FRONT EXTENDED SOUTHEAST OF THIS LOW INTO CENTRAL ILLINOIS...AND A COLD FRONT EXTENDED WEST ACROSS WEST-CENTRAL IOWA. TEMPERATURES ACROSS WESTERN AND SOUTHERN IOWA HAVE WARMED WELL INTO THE 80S. THERE WERE EVEN A FEW 90S. MEANWHILE NORTH OF THE WARM FRONT...THE TEMPERATURES RANGED FROM THE 40S ACROSS NORTHERN WISCONSIN TO THE 60S ACROSS MUCH OF OUR FORECAST AREA. ML CAPES HAVE CLIMB UP TO 250 J/KG ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN WHICH WAS JUST ENOUGH INSTABILITY FOR THE LOW PRESSURE AREA TO GENERATE A FEW SHOWERS ACROSS THIS AREA. THE LATEST HRRR AND SPC WRF SHOW THAT THESE SHOWERS WILL MOVE SOUTHEAST OF THE AREA BY 6 PM. FURTHER TO THE NORTHWEST SOME ADDITIONAL SHOWERS WERE MOVING EAST SOUTHEAST ACROSS NORTHERN WISCONSIN. THESE SHOWERS WERE ASSOCIATED WITH A POTENTIAL VORTICITY ANOMALY MOVING SOUTHEAST ACROSS NORTHERN AND EASTERN WISCONSIN. THESE SHOWERS HAVE BEEN MAINLY EAST AND NORTH OF TAYLOR COUNTY...SO JUST WENT DRY THERE FOR TONIGHT. ON THURSDAY...HIGH PRESSURE WILL NOSE SOUTHWARD INTO THE UPPER MISSISSIPPI RIVER VALLEY. WITH ABUNDANT SUNSHINE...MUCH OF THE AREA WILL MIX UP TO AROUND 850 MB. AS THIS OCCURS...DRIER AIR FROM ALOFT WILL MIX TO THE SURFACE. THIS WILL LOW THE DEW POINTS TO AROUND 20 NORTH OF THE INTERSTATE 94 CORRIDOR...AND IN THE LOWER AND MID 20S ACROSS THE REMAINDER OF THE AREA. THIS IS ABOUT 3 TO 5 DEGREES LOWER THAN THE MOS DEW POINTS. ON THURSDAY NIGHT...THE DEW POINTS WILL REMAIN RATHER DRY. THIS WILL ALLOW THE TEMPERATURES TO DROP OFF RATHER RAPIDLY ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. LOW TEMPERATURES ACROSS THIS AREA WILL LIKELY FALL INTO THE MID AND UPPER 20S. WITH TEMPERATURE AND DEW POINT SPREADS GREATER THAN 8F...CONCERNED THAT THERE WILL BE NO FROST DEVELOPMENT. HOWEVER THESE TEMPERATURES WILL STILL BE COLD ENOUGH TO CAUSE SOME DAMAGE TO UNPROTECTED FRUIT CROPS AND COLD-SENSITIVE FLOWERS. MEANWHILE FURTHER WEST AND SOUTH...THERE WILL INCREASE IN THE CLOUD COVER FROM THE LATE EVENING INTO THE OVERNIGHT. THIS WILL TEMPER THE POTENTIAL FALL IN THE TEMPERATURES AND FROST DEVELOPMENT IN THOSE AREAS. FROM FRIDAY INTO SATURDAY...A LONG WAVE TROUGH WILL BE DIGGING INTO THE WESTERN CONUS. AS THIS OCCURS...THE RIDGE WILL BE AMPLIFYING ACROSS THE CENTRAL UNITED STATES AND CANADIAN PRAIRIES. THIS PATTERN SHIFT STARTED TO DEVELOP LAST NIGHT AND CONTINUED INTO TODAY. AS A RESULT...THE STRONG 800 TO 500 MB FRONTOGENESIS HAS MOVED BACK NORTHWARD INTO SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHERN HALF OF WISCONSIN. DUE TO THIS...THE PRECIPITATION PROBABILITIES WERE RAISED AND MOVED NORTH. 25.12Z GFS AND NAM/WRF BUFKIT SOUNDINGS SUGGEST THAT THE COLUMN WILL BE COLD ENOUGH AND THERE WILL BE THE INTRODUCTION OF ICE CRYSTALS AT TIMES FOR THE RAIN TO CHANGE OVER TO SNOW AT TIMES IN THESE AREAS. THE 25.12Z ECMWF AND 25.18Z NAM/WRF ALSO SHOWS POSSIBILITY. HOWEVER IT IS A BIT FURTHER NORTH AND EAST. THIS MAY SHIFT EVEN FURTHER NORTHWEST IF THE TROUGH IN THE WESTERN CONUS DIGS EVEN MORE. SINCE THE POSSIBILITY OF SNOW HAS BEEN CONSISTENT FOR THE LAST 3 MODEL RUN...JUST INTRODUCED A CHANCE OF SNOW AT THIS TIME. IN ADDITION WITH MORE PRECIPITATION AND CLOUD COVER EXPECTED...HIGH TEMPERATURES FOR SATURDAY HAD TO BE COOLED A FEW MORE DEGREES...AND THIS MAY NOT BE ENOUGH YET. THE FORECAST FOR THIS TIME PERIOD WILL LIKELY REMAIN RATHER FLUENT UNTIL THIS SYSTEM IS SAMPLED FULLY BY THE UPPER AIR NETWORK ON THURSDAY NIGHT. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 338 PM CDT WED APR 25 2012 ON SATURDAY NIGHT...WE MAY HAVE THE POTENTIAL FOR ANOTHER FROST OR FREEZE AS A HIGH PRESSURE SYSTEM BUILD ACROSS THE REGION. THE MAIN QUESTION AT THIS TIME IS HOW FAST WILL THE AREA CLEAR OUT AND WHEN THE WINDS MAY DECOUPLE. FROM MONDAY NIGHT THROUGH WEDNESDAY...THE 25.12Z MODELS CONTINUE TO STRUGGLE ON THE TIMING OF A LONG WAVE TROUGH MOVING OUT OF THE CENTRAL PLAINS. THE ECMWF IS ABOUT 12 HOURS SOONER THAN THE GFS AND HAS ITS PRECIPITATION CHANCES RUNNING FROM MONDAY NIGHT INTO TUESDAY. WITH THE MODELS CONTINUING TO STRUGGLE WITH ITS TIMING JUST STAYED WITH THE ALL BLEND TIMING FOR NOW. && .AVIATION...THROUGH 06Z FRIDAY 1148 PM CDT WED APR 25 2012 A TROUGH OF LOW PRESSURE EXTENDS INTO CENTRAL MINNESOTA FROM AN AREA OF LOW PRESSURE OVER WEST CENTRAL ILLINOIS. HIGH PRESSURE WAS OVER CENTRAL CANADA WITH THE RIDGE AXIS EXTENDING SOUTH INTO NORTH DAKOTA. ENOUGH OF A CYCLONIC FLOW EXISTS BETWEEN THESE TWO FEATURES TO CONTINUE TO PRODUCE SOME CLOUDS OVER NORTHEAST MINNESOTA INTO NORTHERN WISCONSIN. THESE CLOUDS HAVE BEEN TRYING TO WORK SOUTH TOWARD THE AREA BUT AS THEY DUE THEY BECOME SCATTERED AND THEN DISSIPATE. THROUGH THE NIGHT...THE CYCLONIC FLOW SHOULD GRADUALLY SLIP SOUTH INTO THE AREA ALLOWING SOME OF THESE CLOUDS TO GET INTO THE AREA. BOTH THE 26.00Z NAM AND 26.02Z RUC WANT TO BRING IN A BROKEN MVFR TO VFR DECK FOR THE OVERNIGHT HOURS...BUT THIS LOOKS OVER DONE BASED ON CURRENT SATELLITE TRENDS AND OBSERVATIONS. WILL ONLY BRING IN SOME SCATTERED CLOUDS AND IF A CEILING DOES DEVELOP WOULD EXPECT IT TO BE VFR. STEEP LOW LEVEL LAPSE RATES ARE ALSO EXPECTED TO DEVELOP LATE TONIGHT AND PERSIST INTO THURSDAY AFTERNOON ALLOWING SOME GUSTY NORTH WINDS TO DEVELOP AT BOTH SITES. EXPECT THE GUSTS TO BE IN THE 20 TO 25 KNOT RANGE UNTIL THE SURFACE RIDGE BUILDS IN ENOUGH THURSDAY AFTERNOON TO ALLOW THE WINDS TO SETTLE DOWN. && .ARX WATCHES/WARNINGS/ADVISORIES... 338 PM CDT WED APR 25 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
AREA FORECAST DISCUSSION
NWS ALBANY NY
1047 AM EDT THU APR 26 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE EASTWARD ACROSS THE EASTERN GREAT LAKES THIS AFTERNOON...THEN TRACK ACROSS NORTHERN NEW YORK STATE AND NEW ENGLAND TONIGHT. THIS SYSTEM WILL BRING RAIN SHOWERS TO MUCH OF THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. THE LOW WILL STRENGTHEN CONSIDERABLY AS IT LIFTS INTO THE CANADIAN MARITIMES ON FRIDAY...RESULTING IN WINDY AND COOL CONDITIONS ACROSS OUR REGION. HIGH PRESSURE OVER THE UPPER GREAT LAKES AND MIDWEST WILL KEEP US DRY AND UNSEASONABLY COOL THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1047 AM EDT...CLOUDS HAVE BEGUN TO INCREASE ACROSS SOUTHERN AND WESTERN AREAS...HOWEVER...MOSTLY CLEAR SKIES ARE STILL IN PLACE FROM THE CAPITAL REGION NORTHEASTWARD. CLOUDS WILL START TO INCREASE DURING THE NEXT FEW HOURS...WITH MOST AREAS MOSTLY CLOUDY OR CLOUDY BY MID AFTN. THE LATEST LOCAL ESTFWRF AND 3KM HRRR BOTH SHOW RAIN SHOWERS MAKING THEIR WAY INTO THE WESTERN ADIRONDACKS BY THE MID AFTN. HOWEVER...IT MAY TAKE UNTIL THE EVENING FOR SHOWERS TO REACH THE CAPITAL REGION AND POINTS SOUTH AND EAST...SO HAVE ADJUSTED POPS TO SHOW MAINLY CHC POPS FOR MUCH OF THE AFTN...WITH LIKELY/CATEGORICAL POPS NOT ARRIVED TILL ALMOST 00 UTC. TWO SEPARATE SYSTEMS WILL BE AFFECTING THE EASTERN CONUS THIS AFTERNOON INTO TONIGHT. THE FIRST SYSTEM IS A POTENT SHORT WAVE TROUGH EMBEDDED IN NW ZONAL FLOW ACROSS CURRENTLY OVER THE OHIO/WV AREA. AHEAD OF THIS SYSTEM SEVERAL BOUTS OF CONVECTION HAVE BEEN FIRING THIS MORNING DOWNSTREAM OVER THE MID ATLANTIC REGION. THERE IS A DISTINCT AIR MASS CHANGE TO THE SOUTH OF THE MASON DIXON LINE...WITH GREATER MOISTURE AND INSTABILITY. THE AIR MASS OVER THE NORTHEAST WILL REMAIN MORE STABLE. THE SYSTEM THAT WE WILL BE DEALING WITH IN THE NORTHEAST CONUS IS A NORTHERN STREAM SHORT WAVE TROUGH ROUNDING THE BASE OF AN UPPER LEVEL LOW MOVING INTO QUEBEC. THIS WAVE IS CURRENTLY MOVING ACROSS THE EASTERN GREAT LAKES. ISENTROPIC LIFT ASSOCIATED WITH THIS SYSTEM WILL BE RESPONSIBLE FOR THE SHOWERS THIS AFTERNOON. THE SURFACE LOW SHOULD TRACK NORTH OF THE AREA...SO SOME MILDER AIR WILL BRIEFLY MOVE OVERHEAD. WITH RAIN DELAYED UNTIL LATER IN THE AFTERNOON OR EVENING...WILL FORECAST WARMER TEMPS THAN PREVIOUSLY FORECAST WITH GENERALLY LOWER 60S FOR MOST VALLEY LOCATIONS POSSIBLY MID 60S SOUTH OF ALBANY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... THE SYSTEM MENTIONED IN THE NEAR TERM WILL PASS THROUGH DURING THE EVENING HOURS...WITH RAIN CONTINUING THROUGH AROUND MIDNIGHT THEN TAPERING OFF IN MOST AREAS THEREAFTER. THE ONLY EXCEPTION WILL BE ACROSS THE HIGHER TERRAIN MAINLY NORTH OF THE CAPITAL REGION...WHERE WRAP-AROUND MOISTURE AND A NORTHWESTERLY UPSLOPE FLOW WILL RESULT IN SCATTERED TO NUMEROUS RAIN SHOWERS CHANGING TO SNOW SHOWERS AS COLDER AIR FILTERS IN. ANY ACCUMULATIONS WILL BE VERY MINOR AND OVER THE MOUNTAINOUS AREAS. WEST-NORTHWEST WINDS WILL START TO INCREASE SUBSTANTIALLY AFTER MIDNIGHT AS LOW PRESSURE DEEPENS AS IT MOVES INTO NORTHERN NEW ENGLAND AND SPRAWLING HIGH PRESSURE STARTS TO BUILD SOUTHWARD FROM CENTRAL CANADA INTO THE GREAT LAKES. FRIDAY WILL BE A COOL AND WINDY DAY ACROSS THE AREA...AS SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IS MOVES FROM NORTHERN MAINE INTO THE CANADIAN MARITIMES. THE AFOREMENTIONED RIDGE WILL NOT MAKE MUCH EASTWARD PROGRESS...THUS RESULTING IN A STRENGTHENING PRESSURE GRADIENT. WINDS WILL BECOME STRONG AND GUSTY BY LATE MORNING AND ESPECIALLY DURING THE AFTERNOON. ADVISORY LEVEL WINDS OF OVER 30 MPH SUSTAINED AND 45+ MPH GUSTS MAY OCCUR...ESPECIALLY ACROSS THE SOUTHERN 2/3 OF THE AREA. THE ONLY POTENTIAL MITIGATING FACTOR WILL BE MIXING DEPTHS MAY BE RATHER SHALLOW ESPECIALLY IF AN EXPANSIVE STRATOCU CLOUD DECK FORMS IN THE CYCLONIC FLOW REGIME. STILL HAVE ENOUGH CONFIDENCE TO MENTION POTENTIAL FOR ADVISORY LEVEL WINDS IN THE HWO. TEMPS WILL BE AROUND 10-15 DEGREES BELOW NORMAL FOR HIGHS WITH THE WIND MAKING IT FEEL EVEN COLDER. SOME LINGERING UPSLOPE RAIN/SNOW SHOWERS WILL LINGER OVER FAVORED AREAS ESPECIALLY THROUGH THE MORNING BUT SHOULD TEND TO DIMINISH DURING THE AFTERNOON AS DRIER AIR STARTS TO WORK IN. WINDS WILL START TO DECREASE FRIDAY NIGHT AS THE PRESSURE GRADIENT SLACKENS SOMEWHAT WITH THE LOW MOVING FARTHER AWAY FROM THE REGION. COLD TEMPS WILL BE THE MAIN STORY...AS DESPITE A LINGERING BREEZE...A WIDESPREAD ADVECTIVE FREEZE IS EXPECTED ACROSS THE ENTIRE AREA. WILL MENTION POTENTIAL FOR EVENTUAL FREEZE WARNINGS IN THE HWO. DRY AND COOL CONDITIONS WILL CONTINUE THROUGH SATURDAY AS NORTHERN STREAM NW FLOW PERSISTS. ALL SOURCES OF MODEL GUIDANCE CONTINUE TO INDICATE AN WEST-EAST ORIENTED FRONTAL BOUNDARY WITH WEAK WAVES MOVING ALONG THIS BOUNDARY TO BE CONFINED TO AREAS SOUTH OF OUR REGION TOWARDS THE MID ATLANTIC. SOME ADDED CLOUD COVER WILL BE POSSIBLE SATURDAY AFTERNOON FROM THIS SYSTEM BUT CONDITIONS SHOULD REMAIN DRY. TEMPS ARE ONLY EXPECTED TO WARM A FEW DEGREES FROM FRIDAY`S READINGS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A LARGE AND UNSEASONABLY COLD CANADIAN HIGH PRESSURE SYSTEM WILL BE OVER THE REGION SATURDAY NIGHT THROUGH SUNDAY NIGHT. AS THE HIGH MOVES OFF THE NEW ENGLAND COAST MONDAY...TEMPS WILL BEGIN TO MODERATE MONDAY INTO TUESDAY...BUT THE HIGH WILL STILL BE CLOSE ENOUGH FOR DRY WEATHER TO CONTINUE THROUGH TUESDAY. LOWS SATURDAY NIGHT WILL GENERALLY BE BETWEEN 20S AND 30...WITH SOME UPPER TEENS OVER THE ADIRONDACKS. HIGHS SUNDAY IN THE 40S TO THE MID 50S. LOWS SUNDAY NIGHT IN THE 20S TO LOWER 30S. THE WARMUP WILL BEGIN MONDAY WITH HIGHS IN THE UPPER 40S TO AROUND 60. LOWS MONDAY NIGHT WILL BE IN THE 30S...AND HIGHS TUESDAY IN THE MID 50S TO MID 60S. AFTER THE SYSTEM PASSES BY TO OUR SOUTH SATURDAY NIGHT...SKIES WILL BEGIN TO CLEAR...AND EXPECT MAINLY CLEAR TO CLEAR CONDITIONS SUNDAY THROUGH MONDAY NIGHT...AND MOSTLY TO PARTLY SUNNY ON TUESDAY. THE WARMUP WILL CONTINUE INTO WEDNESDAY...BUT THERE WILL ALSO BE INCREASING MOISTURE AS THE SOUTHERLY FLOW PERSISTS AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST. LOWS TUESDAY NIGHT WILL BE IN THE UPPER 30S TO MID 40S. HIGHS WEDNESDAY IN THE UPPER 50S TO MID 60S. SKIES WILL BE PARTLY TO MOSTLY CLOUDY. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS EXPECTED THROUGH MID MORNING. CLOUDS WILL THEN INCREASE AND LOWER AHEAD OF AN APPROACHING WARM FRONT FROM THE SOUTHWEST. RAIN WILL MOVE IN DURING THE MID TO LATE AFTERNOON. CONDITIONS WILL INITIALLY REMAIN VFR IN THE RAIN...BUT EXPECT MVFR CONDITIONS TO MOVE INTO THE KGFL/KALB/KPOU TAF SITES AROUND 21Z- 22Z...AND LOWER TO IFR CIGS AFTER 27/0000Z. BETWEEN 04Z AND 06Z CIGS/VSBYS WILL IMPROVE TO VFR AS STRONG NW WINDS BEGIN TO BLOW. SURFACE WINDS TODAY WILL BECOME SOUTH AND INCREASE TO 8 TO 12 KTS...WITH GUSTS OF 15 TO 20 KTS AT KGFL AND KALB DURING THE AFTERNOON. DURING THURSDAY EVENING WINDS WILL SHIFT TO WESTERLY AT AROUND 10 KTS...AND AFTER MIDNIGHT THE WINDS WILL BEGIN TO INCREASE...REACHING SPEEDS OF 10 TO 15 KTS WITH GUSTS TO 25 KTS. .OUTLOOK... FRI...VFR. VERY WINDY. FRI NIGHT-MON...VFR...NO SIG WX. && .FIRE WEATHER... LOW PRESSURE WILL MOVE EASTWARD ACROSS THE EASTERN GREAT LAKES TODAY...THEN TRACK ACROSS NORTHERN NEW YORK STATE AND NEW ENGLAND TONIGHT. THIS SYSTEM WILL BRING RAINFALL TO MUCH OF THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. THE LOW WILL STRENGTHEN CONSIDERABLY AS IT LIFTS INTO THE CANADIAN MARITIMES ON FRIDAY...RESULTING IN WINDY AND COOL CONDITIONS ACROSS OUR REGION. RELATIVE HUMIDITY VALUES WILL DROP TO A MINIMUM OF AROUND 35 TO 45 PERCENT THIS AFTERNOON. RH VALUES WILL INCREASE TO 80 TO 100 PERCENT TONIGHT...THEN DROP TO BETWEEN 30 AND 45 PERCENT FRIDAY AFTERNOON. WINDS TODAY WILL BE SOUTHERLY AROUND 10 TO 15 MPH. WINDS TONIGHT WILL SHIFT TO THE WEST AND INCREASE TO 10 TO 20 MPH WITH GUSTS TO 30 MPH. WINDS ON FRIDAY WILL BECOME WEST-NORTHWEST AND INCREASE FURTHER TO BETWEEN 20 TO 30 MPH WITH GUSTS OF 40+ MPH LIKELY. && .HYDROLOGY... LOW PRESSURE APPROACHING FROM THE UPPER GREAT LAKES WILL BRING A FAIRLY WIDESPREAD RAINFALL TO THE AREA THIS AFTERNOON INTO THIS EVENING. FORECAST AMOUNTS EXPECTED TO BE AROUND ONE TENTH TO ONE QUARTER OF AN INCH FROM ALBANY SOUTHWARD...WITH ONE QUARTER TO ONE HALF INCH NORTH. THESE RAINFALL AMOUNTS WILL HAVE LITTLE EFFECT ON THE RIVERS...WITH SOME SLIGHT RISES POSSIBLE ACROSS THE UPPER MOHAWK...ADIRONDACK AND UPPER HUDSON BASINS. SOME LIGHT RAIN/SNOW SHOWERS POSSIBLE OVER THE HIGHER TERRAIN LATE TONIGHT. OTHERWISE DRY AND WINDY CONDITIONS ARE EXPECTED FOR FRIDAY. DRY WEATHER IS EXPECTED TO LAST THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK AS WELL. 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. && .EQUIPMENT... DUAL-POLARIZATION UPGRADE STARTED MONDAY...APRIL 23RD...FOR THE NWS ALBANY RADAR KENX AND THE RADAR WILL BE OUT OF SERVICE THROUGH AT LEAST FRIDAY. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/JPV NEAR TERM...FRUGIS/KL/JPV SHORT TERM...JPV LONG TERM...GJM AVIATION...KL/GJM FIRE WEATHER...JPV HYDROLOGY...JPV EQUIPMENT...WFO ALY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
748 AM EDT THU APR 26 2012 .SYNOPSIS... A DEEP LAYERED RIDGE WILL REMAIN TO THE SOUTH...WHILE A COLD FRONT DRIFTS INTO THE FORECAST AREA FRIDAY AND LIFTS NORTH ON SATURDAY. A COLD FRONT WILL MOVE INTO THE AREA LATE SUNDAY INTO MONDAY...AS HIGH PRESSURE BUILDS IN FROM THE NORTH THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DAYBREAK...BROKEN CLOUDS ACROSS THE REGION WITH TEMPS IN THE LOWER TO MID 60S AND WINDS ALREADY GUSTING IN A FEW AREAS GIVEN THE 35-40 KT OF WIND IN THE FIRST 2 KFT FEET OF THE ATMOSPHERE. RADAR HAS SHOWN SOME RETURNS WHICH ARE LIKELY VIRGA. AN EXCELLENT SETUP TODAY FOR BREEZY TO WINDY CONDITIONS TO DEVELOP ACROSS THE FORECAST AREA AS A STRONG SHORT WAVE MOVES INTO THE MID ATLC REGION AND A LONGWAVE TROUGH DIPS THROUGH THE GREAT LAKES. THESE FEATURES AND THE PRESENCE OF A LARGE DEEP LAYERED SUBTROPICAL RIDGE TO OUR S WILL ACT TO TIGHTEN THE LOW LEVEL PRES GRADIENT. LOW LEVEL FIELDS ARE SUBSTANTIAL ON THE ORDER OF 40 TO 50 KT WITH THE NAM INDICATING CLOSE TO 40 KT OF MEAN WIND AROUND CHARLESTON AT 18Z BETWEEN 925 MB AND 800 MB. WE HAVE ISSUED A WIND ADVISORY TODAY FOR OUR NORTHERN ZONES INCLUDING AND CENTERED ON THE CHARLESTON AREA. THE LATEST RUC SHOWS 925 MB EVEN STRONGER AND MORNING CLOUDS ARE EXPECTED TO GIVE WAY TO DEEP MIXING THIS AFTERNOON AND STRONG GUSTY SOUTHWEST WINDS WHICH WILL PROVE FOR DIFFICULT DRIVING ON BRIDGES AND OVERPASSES. HIGHS TODAY SHOULD SOAR TO MID TO UPPER 80S GIVEN LOW LEVEL THICKNESS VALUES AROUND 90 DEGREES AND MORE SUNSHINE ANTICIPATED THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... A SECONDARY SHORT WAVE IS PROGGED TO DIVE SE THROUGH THE MID ATLC AREA TO OUR N TONIGHT AND SOME CONVECTION MAY BRUSH PARTS OF THE CAROLINAS WELL TO OUR N. SOME CLOUDS AND MILD TEMPS WILL PREVAIL ONCE AGAIN WITH A BREEZY EVENING IN PARTS OF COASTAL SOUTH CAROLINA AND WINDS DIMINISHING AFTER DUSK ELSEWHERE. WINDS SHOULD CONTINUE TO DIE DOWN IN THE OVERNIGHT HOURS. TEMPS WILL BE IN THE 60S ALL AREAS. FRIDAY...LATEST 00Z MODEL GUIDANCE IS NOW INDICATING THAT THE BACKDOOR FRONT LINGERING TO THE NORTH COULD DESCEND TO THE SANTEE RIVER BY FRIDAY AFTERNOON. DEEP MOISTURE WILL ALSO INCREASE ALONG THE BOUNDARY AS THE DAY PROGRESSES...THE RESULT OF A DECENT SHORTWAVE TRACKING INTO THE AREA ALONG NEARLY ZONAL FLOW ALOFT. HAVE INTRODUCED A SLIGHT CHANCE FOR SHOWERS/THUNDERSTORMS FRIDAY AFTERNOON ACROSS AREAS NORTH OF THE SAVANNAH RIVER...AS THESE LOCATIONS WILL BE CLOSEST THE MEANDERING FRONT AND ITS ASSOCIATED CONVERGENCE. ONCE THE SHORTWAVE PASSES ACROSS THE SOUTHEAST STATES FRIDAY NIGHT...THE FRONT WILL ONCE AGAIN DRIFT NORTH OF THE FORECAST AREA...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH ACCORDINGLY. HIGH TEMPERATURES ON FRIDAY COULD BE IMPACTED BY THE LOCATION OF THE BACKDOOR FRONT. WILL INDICATE TEMPERATURES REACHING THE LOW TO MID 80S FAR NORTH WHERE THE FRONT COULD LINGER...WHILE CONDITIONS WARM INTO THE UPPER 80S ACROSS SOUTHEAST GEORGIA. SATURDAY...THE BACKDOOR FRONT WILL CONTINUE TO LIFT FARTHER NORTH OF THE FORECAST AREA...WITH DEEP MOISTURE AND CONVERGENCE ALSO MOVING AWAY FROM THE REGION. UPPER RIDGING ACROSS THE BAHAMAS WILL BUILD BACK INTO THE REGION ON SATURDAY...AND WITH A NOTABLE AREA OF NEGATIVE VORTICITY OPENING OVER SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA...RAIN CHANCES WILL BE LESS THAN 10 PERCENT. RISING HEIGHTS ALOFT AND CONTINUED WARM SOUTH/SOUTHWEST FLOW WILL SUPPORT HIGH TEMPERATURES WELL ABOVE SEASONAL NORMALS...REACHING THE UPPER 80S AWAY FROM THE LOCALLY COOLER COASTLINE. SUNDAY...A SHORTWAVE TROUGH WILL DESCEND FROM EASTERN CANADA INTO THE NEW ENGLAND STATES ON SUNDAY...WHILE STRONG CANADIAN SURFACE HIGH PRESSURE SLIPS INTO THE GREAT LAKES REGION AND GRADUALLY BUILDS DOWN THE EAST COAST. THE WEAK BOUNDARY TO THE NORTH WILL BE OVERCOME BY A STRONGER COLD FRONT ALONG THE LEADING EDGE OF THE CANADIAN HIGH...PROGRESSING INTO THE FORECAST AREA SUNDAY NIGHT. THE MAJORITY OF COLD ADVECTION WITH THIS FRONT IS EXPECTED TO BE DELAYED UNTIL AT LEAST THE SUNDAY EVENING HOURS...AND WILL THUS MAINTAIN A HIGH TEMPERATURE FORECAST IN THE MID TO UPPER 80S. PRECIPITATION POTENTIAL ASSOCIATED WITH THE PROGRESSION OF THE FRONT IS MUCH MORE UNCERTAIN...AS STRONG RIDGING FROM THE SOUTH WILL PERSIST WHILE DEEP MOISTURE LOOKS QUITE LIMITED. HAVE THUS INDICATED ONLY SLIGHT CHANCE POPS SUNDAY AND SUNDAY NIGHT FOR PORTIONS OF THE FORECAST AREA. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... MONDAY...DUE TO SOME TIMING DIFFERENCES BETWEEN MEDIUM RANGE MODEL SOLUTIONS REGARDING THE PROGRESSION OF THE COLD FRONT FROM THE NORTH...HAVE CAPPED RAIN CHANCES BELOW 15 PERCENT ON MONDAY. NOTABLE COLD ADVECTION BEHIND THE DESCENDING FRONT WILL SUPPORT COOLER HIGH TEMPERATURES...RANGING FROM THE MID 70S CHARLESTON TRI COUNTY REGION TO THE LOWER 80S FAR SOUTHEAST GEORGIA. TUESDAY THROUGH THURSDAY...THE SURFACE HIGH TO THE NORTH WILL STEADILY SHIFT OFF THE NEW ENGLAND AND MID ATLANTIC COASTLINE TUESDAY THROUGH MID WEEK...WHILE STRONG UPPER RIDGING REMAINS IN CONTROL OF THE PATTERN ALOFT. WINDS WILL VEER AROUND TO EAST AND SOUTHEAST TUESDAY THROUGH THURSDAY...SUPPORTING HIGH TEMPERATURES RISING BACK INTO THE LOW TO MID 80S BY MID WEEK. WILL CAP RAIN CHANCES BELOW 15 PERCENT THROUGH THE EXTENDED PERIOD...CONSIDERING THE DEEP UPPER RIDGING AND ASSOCIATED SUBSIDENCE PERSISTING INTO MID WEEK. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z/27. THE LOW LEVEL INVERSION WILL BREAK SHORTLY GIVING WAY TO A WINDY DAY. THE STRONGEST GUSTS WILL OCCUR AT KCHS DURING THE AFTERNOON... REACHING 30-35 KT AT TIMES...WHEREAS GUSTS AT KSAV SHOULD TOP OUT AROUND 25 KT THIS AFTERNOON. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS EXPECTED TO PREVAIL. && .MARINE... PERIODIC SMALL CRAFT ADVISORY CONDITIONS WERE A BIT OF SURPRISE OVERNIGHT AT GRAYS REEF OVERNIGHT BUT SW FLOW DURING THIS TIME OF YEAR CAN OFTEN PRODUCE LOCALIZED NOCTURNAL ROLLING AND JETTING OFF OUR COAST WHICH CAN LOCALLY ENHANCE WINDS DURING EVENTS WITH STRONGER LOW LEVEL JETS. TODAY...WE THINK THE NOCTURNAL SURGING IN THE NEAR SHORE GEORGIA WATERS WILL EBB WELL BELOW SCA CRITERIA AS THE LAND MASS HEATS AND MIXES WITH THE MARINE INVERSION TAKING PRECEDENCE. ELSEWHERE SCA CONDITIONS ARE LIKELY WITH STRONG GUSTS ALONG THE LAND/SEA INTERFACE IN COASTAL SOUTH CAROLINA AND MARGINAL SCA CONDITIONS OVER OUTER GEORGIA WATERS. THE CHARLESTON HARBOR WILL SEE ANOTHER STRONG RESULTANT SEA BREEZE TAKE SHAPE AND WIND WILL SURGE 20-25 KT THIS AFTERNOON WITH LOCALLY STRONGER GUSTS A GOOD BET. THE SAVANNAH RIVER ENTRANCE SHOULD BECOME GUSTY AT TIMES THIS AFTERNOON BUT SPEEDS SHOULD BE STRONGER INLAND FROM THE INTRACOASTAL. SCA CONDITIONS WILL LINGER THIS EVENING AND DIMINISH LATER TONIGHT AS THE LOW LEVEL JET WEAKENS. WILL STILL NEED TO WATCH FOR SOME LOCAL JETTING CONDITIONS GIVEN THE PATTERN. A WEAK BACKDOOR FRONT COULD DRIFT INTO THE WATERS ADJACENT THE SANTEE RIVER ON FRIDAY...BEFORE QUICKLY LIFTING BACK TO THE NORTH BY FRIDAY NIGHT. SOUTHWEST FLOW WILL PREVAIL SATURDAY AND SUNDAY...LIKELY INCREASING LATE SUNDAY AS A SECONDARY STRONGER FRONT FROM NORTH THE PRESSES TOWARD THE FORECAST AREA. ALTHOUGH THERE ARE SOME TIMING DIFFERENCES EVIDENT IN NUMERICAL MODEL GUIDANCE...PREFER TO INDICATE THE COLD FRONT MOVING INTO THE NORTHERN WATERS BY SUNDAY AFTERNOON AND PUSHING SOUTHWARD THROUGH SUNDAY EVENING. DECENT COLD ADVECTION AND AN ENHANCED PRESSURE GRADIENT COULD SUPPORT SMALL CRAFT ADVISORY WINDS AND SEAS FOR PORTIONS OF THE WATERS LATE SUNDAY INTO MONDAY...AS NORTHEAST FLOW SURGES BEHIND THE FRONT. RIP CURRENTS...GIVEN THE STRONG SW FLOW ASSOCIATED WITH THE RESULTANT SEA BREEZE TODAY...WE HAVE UPGRADED THE RIP CURRENT RISK TO MODERATE ALONG CHARLESTON COUNTY...LOW RISK ELSEWHERE. && .FIRE WEATHER... STRONG AND GUSTY SW WINDS AND EVEN WARMER TEMPERATURES ARE EXPECTED TODAY. HOWEVER RH/S APPEAR TO BE HIGHER THAN PREVIOUS DAYS WITH MINIMUM VALUES ONLY FALLING INTO THE 30-40 PERCENT RANGE. A FIRE DANGER STATEMENT WILL BE ISSUED FOR PORTIONS OF THE FORECAST AREA GIVEN THE VERY WARM TEMPS AND GUSTY WINDS... LOWEST RH VALUES MAINLY ALONG AND W OF I-95 THIS AFTERNOON. A FEW AREAS IN TATTNALL...EVANS...AND CANDLER COUNTIES COULD SEE RH DROP INTO THE 25-30 PERCENT THIS AFTERNOON...NEARING RED FLAG CRITERIA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR SCZ043>045-049-050-052. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR AMZ352. SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR AMZ350-374. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ330. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...79 LONG TERM...79 AVIATION... MARINE...79 FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
948 AM CDT THU APR 26 2012 .DISCUSSION... ISSUED 948 AM CDT THU APR 26 2012 LARGE AREA OF STRATOCUMULUS HAS PUSHED SOUTHWARD INTO FAR NORTHERN ILLINOIS. RUC MODEL LAYER HUMIDITY PLOT INDICATES SOME BREAKS DEVELOPING AS IT MOVES INTO CENTRAL ILLINOIS AROUND MIDDAY. ADDITIONAL DIURNAL CUMULUS EXPECTED TO FORM AROUND MIDDAY AS WELL...ALTHOUGH CU-RULE BEGINS TO ERODE THIS BY MID AFTERNOON. COLD-AIR ADVECTION WILL LIKELY HOLD TEMPERATURES STEADY EARLY THIS AFTERNOON...BEFORE BEGINNING A SLOW FALL. HAVE SENT SOME UPDATES TO THE HOURLY TEMPERATURE AND SKY GRIDS...BUT THESE DO NOT HAVE AN IMPACT ON THE WORDED FORECASTS. GEELHART && .AVIATION... ISSUED 658 AM CDT THU APR 26 2012 HIGH PRESSURE WILL BUILD ACROSS THE CENTRAL ILLINOIS TERMINALS THROUGH THE 12Z TAF VALID TIME. THE HIGH AND ASSOCIATED DRY AIRMASS WILL HELP PROVIDE VFR CONDITIONS THROUGH MOST OF THE PERIOD. HOWEVER...WILL NEED TO KEEP AN EYE ON SOME LOW CLOUDS UPSTREAM ACROSS THE GREAT LAKES AND UPPER MIDWEST. WHILE MUCH OF THIS CLOUD COVER SHOULD MIX OUT TODAY...ENOUGH MAY HOLD TOGETHER TO PRODUCE A PERIOD OF MVFR CIGS LATER TODAY. MID/HIGH CLOUD CLOUDINESS WILL SPREAD ACROSS THE REGION FROM THE SOUTHWEST OVERNIGHT IN ADVANCE OF THE NEXT FEATHER SYSTEM. NORTHERLY WINDS WILL BECOME GUSTY TODAY AS DIURNAL MIXING DEEPENS. THE WINDS ARE EXPECTED TO DIMINISH THIS EVENING AND TREND EASTERLY AS THE CENTER OF THE SURFACE HIGH PASSES TO OUR NORTH. BAK && .PREV DISCUSSION... ISSUED 330 AM CDT THU APR 26 2012 SHORT TERM...TODAY THROUGH SUNDAY STRONG THUNDERSTORMS HAVE JUST PASSED SE OF CLAY COUNTY WITH BRUNT OF THUNDERSTORMS MOVING SE OF THE OHIO RIVER INTO NW KY. THESE WERE THE STRONG TO POTENTIALLY SEVERE THUNDERSTORMS THAT AFFECTED THE SW COUNTIES PAST 6 HOURS AND ARE EXITING WITH A SHORT WAVE. 1001 MB LOW PRESSURE OVER WEST CENTRAL INDIANA WITH ITS COLD FRONT EXTENDING WESTWARD TO NEAR I-72. SURFACE LOW PRESSURE WILL EXIT QUICKLY EAST INTO WESTERN PA BY NOON AND SWEEP THE COLD FRONT THRU SE IL BY MID MORNING. 1033 MB CANADIAN HIGH PRESSURE OVER NORTHERN PARTS OF SASKATCHEWAN AND MANITOBA AND RIDGING SOUTHWARD INTO THE UPPER MIDWEST WILL NOSE INTO IL BY SUNSET AND PROVIDE MOSTLY SUNNY SKIES. COOLER HIGHS TODAY RANGE FROM THE UPPER 60S FROM I-74 NE AND 70-75 SW AREAS. TEMPS WILL SLIP QUICKER THAN NORMAL LATER THIS AFTERNOON DUE TO COLD AIR ADVECTION ESPECIALLY NE AREAS. CANADIAN HIGH PRESSURE RIDGE OVER WI/IL/IN TONIGHT AND PROVIDES FAIR AND MUCH COLDER WEATHER WITH LOWS IN THE MID TO UPPER 30S. MET AND MAV GUIDANCE LOWS AT CHAMPAIGN ARE EVEN NEAR FREEZING. FREEZE WATCHES ARE POSTED NE OF CENTRAL IL OVER NORTHERN INDIANA FOR OVERNIGHT. COOLED LOWS A FEW DEGREES TONIGHT BUT DID NOT GO AS COLD AS FREEZING YET OVER EAST CENTRAL IL SINCE WINDS DO NOT TOTALLY GO LIGHT. MODELS CONTINUE SLOWER WITH RETURNING CONVECTION CHANCES FRIDAY AND LOWER POPS FRIDAY WITH DRY CONDITIONS FRIDAY MORNING WITH 20-30% CHANCE FRIDAY AFTERNOON WITH HIGHEST POPS SW AREAS FRI AFTERNOON. THIS DUE TO LOW PRESSURE EMERGING INTO THE CENTRAL PLAINS WITH A FRONTAL BOUNDARY JUST SOUTH OF MO/IL TRYING TO LIFT BACK NORTH FRIDAY NIGHT INTO SOUTHERN IL AS SURFACE LOW WEAKENS AS IT MOVES INTO SOUTHERN IL BY DAWN SAT. BEST CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS WILL BE OVERNIGHT FRI NIGHT INTO SAT MORNING. MUCH COOLER HIGHS IN THE MID 50S TO NEAR 60F FRI AND SAT OVER CENTRAL IL AND LOWER 60S IN SE IL FRI AND MID TO UPPER 60S SAT. HIGH TEMPERATURE FORECAST TRICKY OVER SE IL SAT DEPENDING ON HOW FAR NORTH WARM FRONT GETS AND WILL BE 70S IN THE WARM SECTOR OVER SOUTHERN IL ALONG AND SOUTH OF I-64. SHOWER CHANCES DIMINISH OVERNIGHT SAT NIGHT THEN DRY SUNDAY WITH STILL BELOW NORMAL HIGHS IN THE UPPER 50S AND LOWER 60S. LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY UNSETTLED WEATHER PATTERN LOOKS TO RETURN DURING THIS TIME PERIOD AND 00Z ECMWF MODEL IS FAVORED OVER THE DRIER GFS MODEL DUE TO ITS RECENT BETTER TRACK RECORD. IL BACK INTO A WSW UPPER LEVEL FLOW DURING THIS TIME WITH NEXT SHORT WAVE EJECTING NE SUNDAY NIGHT AND CHANCES OF SHOWERS AND THUNDERSTORMS. STILL LOOKS LIKE THE BEST CHANCES WILL BE MONDAY NIGHT THROUGH TUE EVENING WITH YET ANOTHER SHORT WAVE EJECTING NE FROM THE CENTRAL PLAINS. TEMPS TO WARM BACK TO ABOVE NORMAL DURING MIDDLE OF NEXT WEEK. KH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1005 AM EDT THU APR 26 2012 .Forecast Update... Issued at 1000 AM EDT Apr 26 2012 Today`s forecast challenge will be to see if another round of thunderstorms fires up out ahead of the slow eastbound cold front currently draped over eastern Kentucky. As the pre-dawn convection continues to move out over the Appalachians, a stable atmosphere took over central Kentucky and southern Indiana in its wake. However, mesoscale models are indicating a refire of the convection over the eastern portions of the forecast area, out ahead of that cold front. This is due to continued diurnal heating and southwesterly flow allowing for warming at the surface and for CIN to diminish. The RUC shows SBCAPE values reaching up to 2000-2500 J/kg with no cap to keep it contained. Bottom line - going to have to monitor this closely as the moisture seems to be the big question right now. Model soundings as well as current WV sat imagery is indicating dry air aloft pushing into the region. Issued at 650 AM EDT Apr 26 2012 Have trimmed back the Severe Thunderstorm Watch some more this morning. Removed all the counties except for the far southeastern CWA where we have seen some renewed convection in the wake of the stronger line. These storms will move out of the area during the next hour. Beyond this morning, we will continue the mention for some shower/thunderstorms over the eastern portion of the forecast area through the afternoon hours. Issued at 600 AM EDT Apr 26 2012 The strongest thunderstorms this morning continue to move south and east across south central Kentucky. Have cancelled a large portion of the watch this morning. Have kept the watch out over the Bluegrass as there are a few stronger storms just to the north of the forecast area. However, any severe weather should be isolated at best. .Short Term (Today through Friday)... Issued at 350 AM EDT Apr 26 2012 The immediate concern this morning is the strong to severe thunderstorms moving into the northwestern portion of the forecast area. The isolated earlier storms have congealed into a larger bowing MCS. Relatively warm temperatures and a strong shortwave have contributed to the enhancement of this system. These storms are expected to continue to remain strong as they track east across the forecast area. We have therefore expanded the Severe Thunderstorm Watch across most of the forecast area this morning. This watch goes through 13Z, with most of the storms expected to be exiting to the east by this time. Large hail will still be a concern with these storms. However, the wind threat is increasing as a bowing line develops and winds may become the main concern as the system moves east. For the rest of the day, rain chances will rapidly decrease. We may have some lingering showers or thunderstorms across east central Kentucky through the afternoon hours. There is a bit of uncertainty however as the atmosphere should be fairly worked over in the wake of this morning`s convection. Winds will shift this afternoon as the cold front moves through. Winds are expected to become gusty ahead of and behind this front. Gusts of 20-25 mph can be expected through the late morning and afternoon hours. Highs today will be in the mid 70s north to the upper 70s in the south. We will dry out tonight as the cold front sinks south of the area. Skies will become partly cloudy to mostly clear with temperatures dropping into the lower 40s in the north to the lower 50s in the south. For Friday, the front to the south of the region will begin to move back to the north as a warm front. Ahead of this front, clouds will overspread the area. We should remain dry through mid day. Showers and thunderstorms will then begin to move in from the southwest. Think that coverage in the afternoon will be fairly limited, so have reduced pops for tomorrow into the low chance range. .Long Term (Friday Night through Wednesday)... Issued at 251 AM EDT Apr 26 2012 Friday Night through Sunday Night... Combination and of deterministic and ensemble guidance continues to show a bit of spread throughout the long term forecast period. In general, this will result in lower than normal forecast confidence. Upper air pattern over the eastern third of the US will remain generally zonal in nature with multiple short waves moving through within the mean flow. So we`ll likely see heights rising and lowering during the period with chances of precipitation occurring as each wave passes through. Previous forecast still looks fairly good compared to this evening`s model runs. Stalled out frontal boundary to the south will likely lift back northward as a warm front Friday evening as an area of low pressure moves out of the Plains and into the upper Midwest. Just how far north this front will lift northward on Saturday is still quite questionable. This will lead to a large gradient of temperatures across the region. We could see as much as a 15-20 degree gradient from south to north with highs in the lower 60s in the north and readings in the upper 70s to the lower 80s in the south. The front looks to sag back south of the area on Sunday resulting a slightly drier forecast for now. Highs Sunday will range from the lower 60s in the north tot he upper 60s to around 70 in the south...with overnight lows dropping into the upper 40s to the lower 50s. Monday through Wednesday... Did not make many changes through this period given the wide spreads in both the deterministic and ensemble guidance. The Ohio Valley looks to remain in a baroclinic zone through the period as a surface frontal boundary remains near the area. This boundary will start off to the south of the area at the beginning of the period and gradually lift northward once again. As multiple mid-level waves aloft scoot past, they will likely result in off and showers and storms. The predictability of the timing of these waves is quite low...thus plan on leaving low chance PoPs in the forecast throughout the period for now. It does appear that the front will likely lift north of the Ohio Valley toward the end of the period resulting in drier and warmer conditions as we head toward the end of the workweek. Highs Mon/Tue should warm into the 70s with upper 70s to the lower 80s returning by Wednesday. Overnight lows will generally be in the 50-60s. && .Aviation (12Z TAF Issuance)... Updated at 650 AM EDT Apr 26 2012 By 12Z the rain should be east of all the TAF sites. The models continue to indicate a layer of moisture moving in this morning and bringing MVFR ceilings. However, looking at satellite and upstream observations, it is hard to find any indication of this. Will therefore keep ceilings VFR at all the TAF sites. Winds will increase this morning ahead of a cold front and wind shift this afternoon. Sustained winds will be 12-15 knots with gusts to 20+ knots. Winds will initially be out of the SW, shifting to the NW by late this afternoon. Skies should become mostly clear overnight with winds dropping below 5 knots out of the north. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........LG Short Term.......EER Long Term........MJ Aviation.........EER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1107 AM EDT THU APR 26 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA THIS AFTERNOON AND BRING THE CHANCE OF SHOWERS TO THE AREA UNTIL THIS EVENING. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA DRY TONIGHT THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... 15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO INCREASE TEMPS ACROSS THE AREA AND LOWER POPS ACROSS THE SOUTH. THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SLIDING ACROSS THE NORTHERN GREAT LAKES, LEAVING THE UPPER OHIO VALLEY IN A WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A LOW IS CENTERED ACROSS THE INDIANA-OHIO BORDER WITH A POORLY DEFINED WARM FRONT EXTENDING EASTWARD ACROSS OHIO AND INTO WESTERN PA. WITH THE WARM FRONT PUSHING INTO THE AREA, WARM AIR ADVECTION HAS ALLOWED TEMPS TO WARM INTO THE 50S ACROSS MUCH OF THE AREA. ALONG AND BEHIND THE LOW, SAT WV IMAGERY INDICATES A DRY PUNCH OF AIR WITH COOLER TDS FILTERING IN ITS WAKE. THE WEAK SURFACE LOW WILL MOVE INTO WESTERN PA THIS AFTERNOON WITH WEAK ISENTROPIC LIFT IN WARM AIR ADVECTION AHEAD OF IT PROVIDING THE CHANCE FOR SHOWERS ACROSS THE AREA. A SCHC OF THUNDER HAS BEEN MENTIONED ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV WITH THE RUC INDICATING MODERATE ELEVATED INSTABILITY THERE. DEEPER MOISTURE WILL SHIFT EAST OF THE AREA BEHIND THE LOW, WITH THE CHANCE OF SHOWERS DIMINISHING FROM WEST TO EAST BY 00Z. WITH SURFACE OBS TRENDING WARMER, FORECAST IS A BLEND OF THE LAMP/HRRR FOR HIGH TEMPS, REACHING THE LOWER TO MID 60S ACROSS MUCH OF THE AREA. TONIGHT...THE LOW WILL SHIFT EAST OF THE AREA WITH COOLER, CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH. GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE LOWER 30S ACROSS THE EASTERN RIDGES. WITH TEMPS FORECAST TO DROP TO MARGINALLY NEAR FREEZING AND UNCERTAINTY WITH CLOUD COVERAGE, A FREEZE WATCH REMAINS IN EFFECT FOR THE HIGHER ELEVATIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... BOUNDARY WILL PUSH SOUTH OF REGION FRIDAY AS PIECE OF COLD CANADIAN HIGH MOVES ACROSS AREA. BOUNDARY WILL QUICKLY RETURN FRIDAY NIGHT AS SHORTWAVE AND SURFACE LOW PRESSURE MOVE FROM THE CENTRAL PLAINS TO THE MID ATLANTIC STATES ALONG FRONT. RAIN WILL SPREAD NORTH ACROSS AREA SATURDAY MORNING WITH LIKELY POPS FOR THE AFTERNOON. 850MB TEMPS NEAR -2C AND BORDERLINE 1000-850MB THICKNESS MAY ALLOW FOR A BIT OF SNOW TO MIX IN AT THE START ACROSS THE NORTH AND SINCE THIS WAS ALREADY IN PREVIOUS FORECAST LEFT AS IS. SURFACE LOW EXITS OFF THE EAST COAST AND PULLS COLD FRONT SOUTH OF REGION SATURDAY NIGHT AND ANOTHER COLD CANADIAN HIGH MOVES SOUTH ACROSS THE REGION. FORECAST USED A BLEND OF THE GFS/ECMWF. TEMPERATURES WILL AVERAGE AT LEAST 10 DEGREES BELOW AVERAGE THROUGH PERIOD. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... COLD HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS SUNDAY WITH A WARMER DAY MONDAY WITH RETURN SOUTHERLY FLOW ON BACKSIDE OF HIGH MONDAY. ANOTHER APPROACHING WARM FRONT WILL SPREAD SCATTERED PRECIPITATION BACK INTO THE REGION TUESDAY AND WEDNESDAY. TEMPERATURES ARE FORECAST TO BE AROUND 10 DEGREES BELOW NORMAL SUNDAY...CLOSE TO NORMAL MONDAY...THEN WARM TO A FEW DEGREES ABOVE NORMAL BY WEDNESDAY. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... A SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW WILL MOVE SOUTHEAST FROM THE UPPER MS VALLEY AND ACROSS THE OH VALLEY LATE TONIGHT AND THURSDAY MORNING. MVFR RESTRICTIONS AND PATCHY IFR CAN BE EXPECTED IN SHOWERS AND ISOLATED THUNDERSTORMS THROUGH THE MORNING HOURS. A FRONT WILL CROSS THE REGION BY LATE DAY CONTINUING THE CHANCE FOR MVFR RESTRICTIONS...AS SUGGESTED BY BOTH LAMP GUIDANCE AND SREF PROBABILITIES. WINDS WILL GENERALLY REMAIN LIGHT OVERNIGHT...WITH THE EXCEPTION OF ANY TAF LOCATION THAT EXPERIENCES A THUNDERSTORM. WINDS WILL SHIFT FROM SE-NW AND BECOME GUSTY TO 25KTS IN THE AFTERNOON WITH THE PASSAGE OF THE FRONT. .OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... A SURFACE RIDGE SHOULD SUPPORT VFR WEATHER FOR THURSDAY NIGHT INTO FRIDAY BEFORE ANOTHER QUICK MOVING LOW PRESSURE SYSTEM BRINGS AREAS OF RAIN WITH MVFR/IFR RESTRICTIONS FRIDAY NIGHT AND SATURDAY. VFR WEATHER SHOULD RETURN FOR SUNDAY AND MONDAY AS HIGH PRESSURE BUILDS SOUTHWARD ACROSS THE GREAT LAKES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR MDZ001. OH...NONE. PA...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR PAZ074-076. WV...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS JACKSON MS
1050 AM CDT THU APR 26 2012 .UPDATE...LATEST NAM AND OTHER HIRES MODELS SHOW A FEW SHOWERS DEVELOPING OVER THE NORTHERN PORTIONS OF THE CWA THIS AFTERNOON INTO THE EVENING. JAN SOUNDING WAS VERY DRY AND CAPPED. TEMPERATURES IN THE MID 80S MAY BREAK THE CAP BUT THERE WERE ALREADY MID LEVEL CLOUDS ACROSS THE DELTA INHIBITING FULL INSOLATION. WL ADD MENTION OF SPRINKLES FOR THIS AFTERNOON ALONG AND NORTH OF HIGHWAY 82 CORRIDOR AND LOOK AT SOME OTHER INFO BEFORE CARRYING ANY POPS THIS EVENING. A FEW SUBTLE WAVES WERE SHOWING UP IN THE NORTHWEST FLOW ALOFT VIA SATELLITE IMAGERY AND RUC ANALYSIS. SURFACE BOUNDARY WAS STILL WELL NORTH DROPPING JUST SOUTH OF THE MID MISSISSIPPI RIVER VALLEY AND WL STALL NORTH OF OUR CWA. HIGH PRESSURE WAS NOTED OVER THE GULF AND PROVIDING A WARM SOUTH TO SOUTHWEST WIND. MID 80S CENTRAL AND SOUTH LOOK ON TARGET. /22/ && .AVIATION...MIXTURE OF VFR AND MVFR THIS MNG ACROSS ARKLAMISS REGION. KGLH/KHBG ARE MVFR /BKN015 CIGS/ AS OF 1430Z AND WILL BECOME VFR OVER THE NEXT COUPLE OF HOURS WITH KGLH HOLING ON TO MVFR POSSIBLY THROUGH 17Z DUE TO OVC150 NOT READILY ALLOWING LOW-LVL MIXING OF THE CURRENT BKN015 STRATUS DECK. A FEW LIGHT SHOWERS COULD BE POSSIBLE ACROSS N/W AREAS THIS AFTN BUT PROBS NOT GREAT ENOUGH TO MENTION IN TAFS ATTM. SW/S WINDS WILL BE ELEVATED LATE MNG-AFTN WITH SUSTAINED WINDS 10-15KT AND GUSTS TO 23KT POSSIBLE (ESPECIALLY FOR NRN SITES). WINDS WILL SUBSIDE OVERNIGHT WITH PATCHY MVFR STRATUS/FOG OCCURRING 27/07-14Z AND MIX OUT THROUGH MID-MNG FRIDAY. /ALLEN/ && .PREV DISCUSSION... /ISSUED 354 AM CDT THU APR 26 2012/ SHORT TERM...TODAY THROUGH FRIDAY NIGHT...STRONG SURFACE HIGH PRESSURE RIDGING WILL PREVAIL OVER MUCH OF THE STATE TODAY...BUT A BOUNDARY WILL DROP SOUTH INTO NORTHERN MISSISSIPPI LATER THIS AFTERNOON. THE MODELS SUGGEST QUITE A BIT OF INSTABILITY ACROSS THE NORTHERN PORTIONS OF THE AREA ALONG WITH PWATS AROUND 1.3 TO 1.4 INCHES LATER THIS AFTERNOON. EXPECT THE CONVECTION TO REMAIN NORTH OF OUR AREA CLOSER TO THE BOUNDARY THIS AFTERNOON THOUGH...AS STRONG CAPPING LOOKS LIKE IT WILL INHIBIT CONVECTIVE DEVELOPMENT OVER OUR AREA. HI-RES MODELS ARE ALSO MAINLY DEVELOPING CONVECTION NORTH OF OUR AREA THIS AFTERNOON AND EVENING. RIDGING AT THE SURFACE AND ALOFT WILL STRENGTHEN OVER THE AREA ON FRIDAY AND FRIDAY NIGHT. TEMPS ARE GOING TO BE VERY WARM THE NEXT COUPLE OF DAYS WITH HIGHS IN THE MID TO UPPER 80S. THE SURFACE PRESSURE GRADIENT WILL TIGHTEN EACH AFTERNOON TODAY AND FRIDAY WITH GUSTS FROM 25-30 MPH LIKELY...ESPECIALLY UP IN THE DELTA. MADE A FEW ADJUSTMENTS TO GUIDANCE...MAINLY TO HIGH TEMPS AND POPS IN THE NORTH. EXPECT TEMPS TO BE SLIGHTLY HIGHER THAN WHAT MAV IS INDICATING...SO BUMPED HIGHS UP A DEGREE OR TWO OVER MOST OF THE AREA. AS PREVIOUSLY TALKED ABOUT EXPECT THE STRONG CAP TO INHIBIT CONVECTIVE DEVELOPMENT OVER THE AREA...SO CUT POPS IN THE NORTH./15/ LONG TERM...UPPER RIDGING PERSISTS THIS WEEKEND...ALONG WITH GENERALLY ANTICYCLONIC FLOW AT 850 MB. THE REMNANTS OF THE SURFACE TROUGH DROP INTO THE REGION BY SUNDAY BUT WEAK SURFACE CONVERGENCE ASSOCIATED WITH THIS SHOULD NOT OVERCOME THE HEALTHY CAPPING/CIN VALUES THAT WILL CONTINUE. ALTHOUGH CAPPING WILL REMAIN IN PLACE THIS WEEKEND AND CHANCES OF AFTERNOON CONVECTION ARE VERY LOW...OF SOME CONCERN IS THE FACT THAT INCREASING CAPE AND HIGH LAPSE RATES INDICATE THAT IF AN ISOLATED CELL CAN GET GOING AND PUSH THROUGH THE CAP THEN A SEVERE STORM COULD DEVELOP BUT WITH CHANCES SO LOW NO MENTION OF PRECIP WILL BE ADDED AT THIS TIME FOR SATURDAY OR SUNDAY. MODELS BEGIN TO TRY TO ERODE THE UPPER RIDGE MONDAY AND TUESDAY...WEAK WAVES LIFTING INTO THE REGION IN SWLY FLOW ALOFT ON THE WRN FRINGES OF THE HIGH. WEAK CAPPING CONTINUES BUT WILL BE LESS PRONOUNCED THAN OVER THE WEEKEND AND LAPSE RATES WILL REMAIN HIGH. SLIGHT CHANCE POPS PAINTED BY MOS FOR EARLY NEXT WEEK LOOK REASONABLE IF THE RIDGE DOES INDEED BEGINS TO WEAKEN. WITH RELATIVELY LOW COVERAGE A RELATIVELY LONG PERIOD AWAY WILL NOT ADD CONVECTION RISKS TO THE HWO AT THIS TIME FOR NEXT WEEK BUT A SLIGHT POTENTIAL DOES EXIST IF THE UPPER RIDGE DOES BEGIN TO GIVE WAY. PERSISTENT UPPER RIDGING WILL RESULT IN A CONTINUED WARM SPELL ACROSS THE AREA...PARTICULARLY FOR AFTERNOON HIGHS. DAYTIME READINGS IN THE UPPER 80S ARE FORECAST BY MEX MOS FOR SUNDAY/MONDAY DURING AND IMMEDIATELY FOLLOWING THE PEAK OF UPPER RIDGING. CONSIDERING THAT MANY LOCATIONS CLIMBED INTO THE MID 80S YESTERDAY AND RECORD HIGHS CLIMB INTO THE LOW TO MID 90S BY MONDAY...MEX MOS NUMBERS DO NOT LOOK UNREASONABLE AND WILL BE FOLLOWED. /03/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 85 62 86 63 / 9 8 9 11 MERIDIAN 87 61 87 61 / 10 11 7 13 VICKSBURG 86 62 85 62 / 9 7 11 12 HATTIESBURG 88 63 86 62 / 3 5 2 7 NATCHEZ 85 63 85 64 / 4 6 2 7 GREENVILLE 84 65 85 65 / 17 14 12 13 GREENWOOD 83 64 84 64 / 17 13 11 13 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22/ALLEN/15/03
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1045 AM EDT THU APR 26 2012 .SYNOPSIS... ...STRONG AND GUSTY SOUTHWEST WINDS INTO THIS EVENING...STRONG LOW PRESSURE WILL PASS TO OUR NORTH TODAY...ACCOMPANIED BY STRONG WINDS. SCATTERED THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING COULD BRING EVEN STRONGER WIND GUSTS...ESPECIALLY ACROSS NORTH CAROLINA. A COLD FRONT WILL DIP INTO THE COASTAL CAROLINAS LATE TONIGHT... STALLING FRIDAY...THEN LIFTING NORTH SATURDAY. THE FRONT WILL RETURN SOUTH LATE SATURDAY NIGHT AS CANADIAN HIGH PRESSURE SURGES SOUTH ALONG THE ATLANTIC COAST INTO MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM THURSDAY...SURFACE LOW PRESSURE IN OHIO WILL MOVE INTO NEW ENGLAND TONIGHT...AS A SECONDARY LOW DEVELOPS ACROSS VIRGINIA AND MOVES OFFSHORE THIS EVENING. BOTH OF THESE LOWS ARE THE RESULT OF UPPER DISTURBANCES: A STRONG ONE OVER LAKE SUPERIOR AND A WEAKER ONE MOVING INTO THE VIRGINIA/NC MOUNTAINS THIS MORNING. AN IMPRESSIVE SQUALL LINE ACROSS THE SOUTHERN APPALACHIANS THIS MORNING HAS PUSHED EAST OF THE MOUNTAINS AND TO INTERSTATE 77 AT THE TIME OF THIS WRITING. EVEN THE HOURLY HRRR RUNS HAVE FAILED TO KEEP UP WITH THE RAPID SOUTH AND EASTWARD MOTION OF THIS LINE. TYPICALLY WE EXPECT ORGANIZED CONVECTIVE SYSTEMS TO WEAKEN DURING THE LATE MORNING DUE TO DETERIORATION OF THE LOW-LEVEL JET AS SUNSHINE STEEPENS LOW-LEVEL LAPSE RATES AND THE MOMENTUM OF THE JET BECOMES DISTRIBUTED OVER A DEEPER LAYER DOWN TO THE SURFACE. THE HRRR SHOWS WEAKENING OF THE LINE BETWEEN NOW AND 16Z/NOON EDT...BUT STILL MAINTAINS AT LEAST SOME CONVECTIVE ACTIVITY ARRIVING IN THE BENNETTSVILLE AND LUMBERTON AREAS BY 17-18Z/1-2 PM EDT. THE ATMOSPHERE WILL BECOME MODERATELY UNSTABLE ACROSS THIS REGION WITH SURFACE-BASED CAPE RISING TO 1500 J/KG...-5 LIFTED INDICES...AND LITTLE CAPPING. FORECAST WIND PROFILES ALSO SHOW SUFFICIENT VERTICAL SHEAR FOR ORGANIZED STORMS (0-6 KM BULK SHEAR 30-40 KT). ANY ACTIVITY SHOULD MOVE EAST ACROSS INTERIOR SOUTHEAST NORTH CAROLINA DURING THE AFTERNOON...WITH DAMAGING WIND GUSTS THE PRIMARY THREAT. FARTHER SOUTH INTO SOUTH CAROLINA...A CONVECTIVE CAP BETWEEN 800-700 MB (6500-10000 FT AGL) WILL ACT TO INHIBIT STORM DEVELOPMENT AND THERE IS A MUCH LOWER CHANCE OF STORMS HERE DURING THE DAYLIGHT HOURS. EVEN THE SEABREEZE MAY NOT EXTEND HIGH ENOUGH INTO THE ATMOSPHERE TO OVERCOME THIS CAP AND WE ARE MAINTAINING A DRY FORECAST INTO LATE AFTERNOON AWAY FROM THE NORTH CAROLINA STATE LINE. VERY BREEZY CONDITIONS ARE EXPECTED TODAY DUE TO A TIGHT PRESSURE GRADIENT ALONG THE SOUTH SIDE OF THE DEVELOPING SURFACE LOW IN VIRGINIA. RADAR WIND PROFILES SHOW 50 KT WINDS AS LOW AS 4000 FT AGL...AND 30-40 KT WINDS AT 1000-2000 FT AGL. STRONG INSOLATION SHOULD STEEPEN LAPSE RATES SUFFICIENTLY TO BRING GUSTS TO 30 KT (35 MPH) TO THE SURFACE RATHER EASILY TODAY EVEN OUTSIDE OF THUNDERSTORMS. TONIGHT MODELS SHOW A SECOND UPPER DISTURBANCE DIVING SOUTHEAST ACROSS THE AREA. EARLIER STORMS ACROSS CENTRAL NORTH CAROLINA SHOULD HAVE SHARPENED UP A FRONTAL BOUNDARY WHICH MAY ACT TO PROVIDE A LITTLE STRONGER FOCUS FOR STORMS AFTER DARK. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT IN THE AREA FRI WITH THE LATEST GUIDANCE NOW STALLING THE FRONT ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA AT THE START OF THE PERIOD. FRONT SLOWLY LIFTS NORTH LATER FRI INTO FRI NIGHT AS SURFACE WAVE AND SHORTWAVE ALOFT MOVE EAST ACROSS THE AREA. FORECAST SOUNDINGS AND CROSS SECTIONS SHOW A NARROW BAND OF DEEP MOISTURE LIFTING INTO THE AREA LATE FRI NIGHT. WHILE THERE IS NO SURFACE BASED INSTABILITY TO SPEAK OF THERE IS SOME ISENTROPIC LIFT ALONG THE FRONT COINCIDENT WITH DIVERGENCE ALOFT. IT NOW APPEARS THE BEST PRECIP CHANCES WILL BE FRI NIGHT AS THE FRONT LIFTS BACK NORTH AND WEAK SURFACE WAVE TRAVELS EAST. LACK OF STRONG FORCING AND NOCTURNAL TIMING WILL LIKELY RESULT IN LIGHT PATCHES OF RAIN OVERNIGHT...LOW CHANCE SHOULD COVER MOST OF THE AREA WITH ONLY A COUPLE HUNDREDTHS OF QPF. FORECAST FOR SAT REMAINS UP IN THE AIR. 00Z GFS PUSHES THE SURFACE FRONT NORTH OF THE REGION AS WEAK 5H RIDGE BUILDS NORTH AND LOW PRESSURE MOVES THROUGH THE KY VALLEY. HOWEVER THE NAM/CANADIAN/AND 12Z ECMWF KEEP THE FRONT STALLED IN THE AREA WITH SHOWERS AND THUNDERSTORMS DEVELOPING IN THE AFTERNOON. GIVEN THE CONSENSUS BETWEEN THE 00Z NAM/CANADIAN...12Z ECMWF AND HPC WILL FAVOR THE WETTER COOLER SOLUTION FOR SAT. GOING TO INTRODUCE POP FOR SAT/SAT NIGHT...THOUGH ONLY SLIGHT CHANCE FOR NOW AND KNOCK BACK TEMPS A DEGREE OR TWO. HOWEVER...IF THE GFS SOLUTION IS THE CORRECT ONE TEMPERATURES COULD BE 5 DEGREES WARMER SAT AFTERNOON WITH NO THREAT OF PRECIP. FRONT EVENTUALLY PUSHES NORTH OF THE AREA LATE SAT OR SAT NIGHT WITH WEAK WARM ADVECTION KEEPING TEMPERATURES ABOVE CLIMO OVERNIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT WILL DROP SOUTH ACROSS THE AREA SUN...FOLLOWED BY STRONG CANADIAN HIGH RIDGING DOWN THE COAST. PASSAGE OF THE FRONT IS LOOKING LESS AND LESS LIKE A PRECIP EVENT. DEEP WEST TO NORTHWEST FLOW AHEAD OF THE FRONT HELPS DRY THE COLUMN...AIDED BY WEAK 5H RIDGE BUILDING OVER THE SOUTHEAST. NORTHEAST FLOW CONTINUES MON INTO TUE WITH SURFACE HIGH WEDGING DOWN THE EASTERN SEABOARD. SURFACE RIDGE AXIS STARTS TO SHIFT OFFSHORE LATE TUE BUT IS INITIALLY SLOW TO MOVE SOUTHEAST OF THE AREA. RETURN FLOW STARTS TO DEVELOP ON WED AS THE CENTER OF THE HIGH PUSHES FARTHER OFF THE EAST COAST. DO SEE A HINT OF A WEAK COASTAL TROUGH DEVELOP TUE NIGHT INTO WED BUT VERY DRY AIR IN PLACE MINIMIZES THE THREAT OF PRECIP. PERIOD REMAINS DRY WITH SURFACE AND UPPER RIDGING IN PLACE. TEMPERATURES SUN AHEAD OF THE FRONT SHOULD BE NEAR CLIMO...BUT THEN MON AND TUE END UP BELOW CLIMO IN COOL NORTHEAST FLOW. MON WILL LIKELY BE THE COOLEST DAY WITH SOME WARMING TUE AS THE AIR MASS MODIFIES. RETURN FLOW AT THE END OF THE PERIOD WILL RETURN TEMPS BACK TO CLIMO. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 12Z...STRONG LOW LEVEL JET WILL CAUSE SOME WIND SHEAR EARLY IN THE PERIOD UNTIL MIXING PRODUCES STRONGER WINDS AT THE SURFACE. TIGHT SOUTHWESTERLY GRADIENT WILL PRODUCE WIND GUSTS TO NEAR 30 KTS TODAY. A SHORT WAVE MOVING INTO WESTERN NORTH CAROLINA WILL MOVE INTO THE WESTERN TERMINALS BY MID AFTERNOON...REACHING THE COAST BY LATE AFTERNOON. MODERATE UNCERTAINTY WITH RESPECT TO COVERAGE AND TIMING. BRIEF HEAVY RAIN IS POSSIBLE. TONIGHT...SOME LINGERING CONVECTION IS POSSIBLE...BUT SHOULD BE ISOLATED. WINDS WILL DIMINISH A BIT...BUT SHOULD REMAIN AROUND 10-15 KTS. EXTENDED OUTLOOK...VFR WITH LOW CHANCES OF PRECIPITATION THROUGH THE PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM THURSDAY...A TIGHT PRESSURE GRADIENT ALONG THE SOUTH SIDE OF LOW PRESSURE IN VIRGINIA WILL MAINTAIN WINDY CONDITIONS ACROSS THE COASTAL WATERS TODAY. SUSTAINED WINDS HAVE ALREADY REACHED 25 KT WITH GUSTS NEAR 30 KT AT THE FRYING PAN SHOALS WEATHER BUOY. SUSTAINED WINDS COULD APPROACH 30 KT LATER THIS AFTERNOON AS THE CORE OF THE STRONGEST WINDS MOVES ACROSS THE AREA. WIND SPEEDS SHOULD REMAIN JUST BELOW GALE (34 KT) CRITERIA...BUT THIS SHOULD CERTAINLY BE THOUGHT OF AS A "HIGH END" SMALL CRAFT ADVISORY. RADAR COMPOSITES SHOW A SQUALL LINE ACROSS THE WESTERN CAROLINAS THAT SHOULD DIE OUT BEFORE MAKING IT OFFSHORE THIS AFTERNOON. MODELS DO SHOW HOWEVER A SECOND UPPER DISTURBANCE DIVING SOUTHEAST INTO THE REGION TONIGHT THAT MAY IGNITE SOME SHOWERS AND STORMS...ESPECIALLY ACROSS THE NC WATERS. SEAS HAVE BUILT AS HIGH AS 8 FEET OUT AT THE FRYING PAN SHOALS BUOY...3-4 FT AT OUR NEARSHORE CORMP BUOYS. SEAS SHOULD BUILD ANOTHER 1-2 FT BY LATE THIS AFTERNOON. WITH THE STRONG SOUTHWEST WINDS CONTINUING. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 AM THURSDAY...SOUTHWEST FLOW OVER THE WATERS AT THE START OF THE PERIOD WILL DECREASE AND BECOME HIGHLY VARIABLE AS COLD FRONT DROPS IN FROM THE NORTH. APPEARS FRONT WILL STALL ACROSS THE WATERS...NEAR CAPE FEAR. THE RESULT BEING LIGHT WINDS WITH A NORTHERLY COMPONENT ON THE NORTH SIDE OF THE FRONT AND WHILE LIGHT SOUTHERLY WINDS ARE FOUND SOUTH OF THE BOUNDARY. STALLED BOUNDARY LIFTS NORTH AS A WARM FRONT FRI NIGHT WITH SOUTHERLY FLOW DEVELOPING ACROSS ALL WATERS EARLY SAT. GRADIENT BECOMES PINCHED LATE SAT AND SAT NIGHT WITH SPEEDS INCREASING TO 15 TO 20 KT BY THE END OF THE PERIOD. SEAS 3 TO 5 FT FRI MORNING SUBSIDING TO 2 TO 4 FT LATE FRI INTO SAT BEFORE INCREASE IN WINDS SAT NIGHT RETURNS SEAS TO 3 TO 5 FT. MAIN WAVE COMPONENT WILL BE SOUTHERLY SWELL FROM PROLONGED SOUTH TO SOUTHWEST WINDS. LIGHT NORTHEAST FLOW DEVELOPING FRI MAY ADD A LITTLE CHOP TO NC WATERS. LONG TERM /SUNDAY THROUGH MONDAY/... AS OF 3 AM THURSDAY...COLD FRONT WILL DROP SOUTH ACROSS THE WATERS FROM THE NORTH ON SUN WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT. BRIEF PERIOD OF SOUTHERLY FLOW SUN MORNING WILL BE REPLACED BY NORTH TO NORTHEAST FLOW BY MIDDAY. INITIALLY GRADIENT WILL BE ON THE WEAK SIDE WITH NORTH TO NORTHEAST FLOW AROUND 10 KT. COLD SURGE SUN NIGHT AS THE HIGH PUSHES SOUTH HELPS TIGHTEN THE GRADIENT WITH SPEEDS INCREASE TO 15 TO 20 KT AFTER MIDNIGHT. NORTHEAST FLOW REMAINS 15 TO 20 KT INTO MON AFTERNOON BEFORE GRADIENT STARTS TO RELAX AND SPEEDS DROP CLOSER TO 15 KT. SEAS START OUT 3 TO 4 FT BUT ONCE NORTHEAST FLOW PICKS UP SUN NIGHT SEAS START TO BUILD. HEADLINES MAY BE REQUIRED SUN NIGHT AND MON. DEVELOPING NORTHEAST WIND WAVE ON TOP OF SOUTHERLY SWELL WILL CREATE CHAOTIC SEAS ON MON. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252. && $$ NEAR TERM...TRA SHORT TERM...III LONG TERM...III AVIATION...43
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1103 AM EDT THU APR 26 2012 .SYNOPSIS... A COMPLEX AREA OF LOW PRESSURE AND TRAILING COLD FRONT WILL CROSS THE CENTRAL PENNSYLVANIA TODAY. EXPECT AN INCREASING CHANCE OF SHOWERS ACROSS THE AREA THIS AFTERNOON. HIGH PRESSURE WILL SPREAD INTO THE REGION TONIGHT AND FRIDAY BRINGING COOLER AND DRIER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... FRONTAL SYSTEM WITH BROKEN LINE OF SHOWERS HEADING INTO CWA LATE THIS MORNING. NUDGED POPS WITH A BLEND OF HRRR AND NAM. INSTABILITY MARGINAL AND WITH MINIMAL CHANCES OF THUNDER. LITTLE ELSE CHANGED IN FORECAST AS QPF TEMPS AND WIND LOOK SOLID. TONIGHT...A MUCH DRIER AIR MASS OVERSPREADS THE REGION IN WAKE OF COLD FRONT WITH GEFS PWATS FALLING TO BTWN 1-2SD BLW NORMAL TONIGHT. OVER THE BULK OF CENTRAL PA...THIS WILL RESULT IN CLEARING SKIES. HOWEVER...AIR MASS WILL BE COLD ENOUGH TO SUPPORT LAKE EFFECT STRATO-CU AND SCT -SHSN ACROSS THE NW MTNS THRU THE NIGHT. NO ACCUMS MENTIONED...AS BULK OF ACTIVITY SHOULD DIE DOWN BEFORE SFC TEMPS REACH FREEZING. AS A SECONDARY LOW DEVELOPS ALONG THE NEW ENG COAST AND TRACKS NEWD TWD THE MARITIMES...EXPECT A BREEZY THURS NGT AS GRADIENT TIGHTENS WITH SFC RIDGE SHIFTING SEWD THRU THE GRT LKS. DESPITE THE CLOUD COVER AND WINDS...NWP GUIDANCE INDICATES AIR MASS MAY BE COLD ENOUGH TO PUSH TEMPS BLW FREEZING ACROSS THE ALLEGHENY MTNS. HAVE THUS ISSUED A FREEZE WATCH FOR OUR NORTHERN AND WESTERN MTNS TONIGHT. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... SFC RIDGE AXIS WILL SHIFT EWD FM THE UPPER MIDWEST ON FRI REACHING CENTRAL PA FRI NGT. THE MAIN FCST ISSUES FOR FRIDAY ARE FIRE WEATHER DURING THE DAY AND FROST/FREEZE AT NIGHT. DEEP BLYR MIXING WILL TAP STG WINDS ALOFT...AND LLVL CAA WILL HELP PROMOTE FQNT SFC WNDS GUSTS BTWN 20-30KTS. THE DEEP BLYR MIXING SHOULD ALSO DROP DEWPOINTS THRU THE AFTN WITH FCST RH VALUES FALLING INTO THE UPPER 20S TO LOW 30S OVER MUCH OF THE S-CENTRAL MTNS AND LOWER SUSQ VLY. DEPENDING ON HOW MUCH RAIN FALLS OVER THIS AREA TDY...THERE IS A GOOD CHANCE OF ELEVATED FIRE WEATHER CONDS TOMORROW AFTN. THE FOCUS WILL SHIFT TO POTENTIAL FROST/FREEZE HEADLINES TOMORROW NGT AS ENSEMBLE THREATS PAGE SHOWS A HIGH PROBABILITY/CONFIDENCE IN FROST/FREEZE CONDS. THIS WILL LKLY BE THE FIRST OF SEVERAL FROST/FREEZE HEADLINES ESPECIALLY FOR THE NRN MTNS. CONSIDERED ISSUING A FREEZE WATCH FOR TOMORROW NGT BUT AFTER COLLABORATION WILL JUST KEEP MENTION IN HWO. CONFIDENCE IN THE FCST HAS DROPPED BELOW AVG THROUGH THE WEEKEND. THIS IS MAINLY DUE TO INCREASING COMPLEXITIES IN THE LG SCALE FLOW PATTERN. THERE ARE MULTIPLE FEATURES TO CONTEND WITH INCLUDING THE EJECTION OF SW UPPER LOW ENERGY ON THURS...EVOLUTION OF TROUGH-RIDGE CONFIGURATION OVR THE NRN PLAINS AND UPPER MS VLY AND EVENTUAL INTERACTIONS WITH THE NERN CONUS TROUGH. FOLLOWED HPC RECOMMENDATIONS VERY CLOSELY AS A RESULT AND BLENDED THE OP ECMWF/CANADIAN GLOBAL WITH PREV FCST TO DERIVE TONIGHT`S NDFD GRIDS. THESE MODELS SEEMED TO PROVIDE A BETTER INTERMEDIATE TIMING/AMPLITUDE OF THE SERN CANADA/NE CONUS FLOW. THERE IS CONSIDERABLE UNCERTAINTY IN THE SPECIFICS BUT FOLLOWING THE PREFERRED SOLN YIELDS THE BEST CHC OF RAIN ON SAT AFTN BEFORE THE E-W FNTL ZONE IS SHUNTED SWD ON SUN BY SPRAWLING CANADIAN HIGH BECOMING ANCHORED OVER ONT/QUE. DAYTIME HIGHS WILL BE WELL BELOW CLIMATE NORMALS ESPECIALLY ON SATURDAY. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... THE LATEST MEDIUM RANGE GUIDANCE SHOWS THE NERN CONUS TROF PUSHING OFF THE ECOAST AS AN UPPER RIDGE SLIDES EWD FROM THE OH VLY AND GRT LKS. FOLLOWING A COOL END TO THE MONTH OF APRIL...RETURN FLOW AND RISING HEIGHTS WILL SPELL A WARMING TREND INTO EARLY MAY. INDIVIDUAL SHORTWAVES...WHICH ARE VERY HARD TO RESOLVE AT THESE RANGES...WILL MODULATE OPPORTUNITIES OF PCPN. INTRODUCED POPS STARTING MONDAY NGT AND CARRIED SCHC/CHC THRU WED. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... LOW PRESSURE APPROACHING FROM THE MIDWEST WILL SPREAD LOWERING CLOUDS ACROSS CENTRAL PA EARLY THIS MORNING AND EVEN A FEW SPRINKLES ACROSS SOUTHERN PA. HOWEVER...DUE TO DRY AIR IN THE LOW LEVELS EXPECT CIGS TO REMAIN VFR WITH A LGT SE WIND UNTIL LATE MORNING. AS LOW PRES NEARS THE AREA...EXPECT SHRA TO BECOME NUMEROUS WITH WIDESPREAD MVFR CIGS LIKELY BY AFTN. TRAILING COLD FRONT WILL SWEEP THRU THE AREA BTWN 21Z-01Z...ACCOMPANIED BY A WIND SHIFT FROM THE S TO THE NW. FOR MUCH OF THE AREA...EXPECT CLEARING TO DEVELOP AFTER PASSAGE OF THE COLD FRONT. HOWEVER...RESIDUAL LOW LVL MOISTURE ASCENDING THE W MTNS MAY PRODUCE A PERIOD OF IFR CIGS AT JST DURING THE EVENING HRS. AT BFD...MOISTURE FLOWING OFF OF LK ERIE WILL LIKELY RESULT IN PERSISTENT MVFR STRATO-CU THRU 06Z. OUTLOOK... FRI...VFR. SAT...CHC RAIN/LOW CIGS SOUTH...POSS MIX WITH SNOW LAURELS/SC MTNS. SUN-MON...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR PAZ004>006-010>012-017-018-024-033-037-041-042. && $$ SYNOPSIS...ROSS/STEINBUGL NEAR TERM...ROSS/FITZGERALD SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS PUEBLO CO
205 PM MDT THU APR 26 2012 .SHORT TERM... (TONIGHT AND FRIDAY) ...MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE POTENTIAL FOR PORTIONS OF THE SOUTHEAST PLAINS THROUGH THE OVERNIGHT HOURS... COMPACT CLOSED LOW CIRCULATION ACROSS AZ WILL CONTINUE TO LIFT TO THE NORTHEAST ACROSS SOUTHERN AND SOUTHEAST COLORADO BETWEEN 06Z AND 12Z. SE SFC WINDS HAVE ADVECTED LOWER 50 DEW POINTS INTO BACA COUNTY...WITH 40S ALONG THE ARKANSAS RIVER TO THE NORTH. MEANWHILE...SOUTHWEST WINDS HAVE DROPPED DEW POINTS INTO THE 20S ACROSS THE HIGH VALLEYS...WITH DEW POINTS DROPPING ACROSS THE NRN RATON MESA AND PALMER DIVIDE AS DRY LINE TAKES SHAPE. MODELS STILL PAINT THE SCENARIO OF A COUPLE OF WAVES OF CONVECTION DEVELOPING ACROSS THE MOUNTAINS AND MOVING OFF INTO THE SOUTHEAST PLAINS. FIRST WAVE IS CURRENTLY DEVELOPING ACROSS THE MTS NOW...AND EXPECT CONVECTION TO DEVELOP ALONG THE SFC TROF/DRY LINE BY 20-21Z. SPC MESO ANALYSIS CURRENTLY SHOWING CAPES OF AROUND 1000 TO NEAR 1500 J/KG ACROSS THE SOUTHEAST PLAINS WITH DEEP LAYER SHEARS RUNNING AROUND 40-50 KTS. HRRR...RUC13...AND NAM12 MIX THE DEW POINTS OUT ALONG THE I-25 CORRIDOR BACK INTO THE 30S...THOUGH HANG TOUGH WITH THE 40S-LOWER 50 DEW POINTS ACROSS THE SOUTHEAST COUNTIES OF KIOWA...BENT...PROWERS...AND BACA...AS WELL AS EASTERN PORTIONS OF CROWLEY...OTERO...AND LAS ANIMAS COUNTIES. INITIALLY LCLS WILL START OUT RATHER HIGH...WITH THE PROXY T/TD SPREADS RUNNING AROUND 30 DEGREES ACROSS THIS REGION. HOWEVER...WITH THE APPROACH OF THE UPPER TROF...STRENGTHENING SOUTHEASTERLY WINDS WILL ADVECT 40 DEW POINTS BACK INTO THE NRN I-25 CORRIDOR...WITH 50S TO LOWER 60 DEW POINTS ACROSS THE SOUTHEAST PLAINS. COUPLED WITH COOLING TEMPS ALOFT WITH INCOMING SYSTEM...THIS SHOULD AMP UP CAPE VALUES TO BETWEEN 1500-2500 J/KG...WITH HIGHEST VALUES ACROSS BACA COUNTY BY 06Z. HELICITIES INCREASE TO 500+ M2/S2 BY 06Z WITH FORCING FROM THE SYSTEM LIKELY TO WEAKEN OR BREAK THROUGH WHATEVER CAP REMAINS. THUS...SEVERE WEATHER EVENT LOOKS TO START OUT AS A LARGE HAIL...AND DAMAGING WIND SCENARIO THIS AFTERNOON...AND EVOLVE TO INCLUDE AN ISOLATED TORNADO POTENTIAL AFTER 9 PM ACROSS THE FAR EASTERN COUNTIES. THIS ATYPICAL LATE NIGHT TORNADO THREAT FOR THIS REGION SHOULD LAST UNTIL AROUND 2 AM. STILL THINK THE MAIN THREAT AREA WILL EXTEND EAST OF A LINE FROM LIMON...TO LA JUNTA...TO KIM. THOUGH IF RUC IS CORRECT IN SPREADING 40 TO LOWER 50 DEW POINTS BACK WESTWARD INTO THE I-25 CORRIDOR AFTER THE FIRST ROUND OF AFTERNOON THUNDERSTORMS...THEN PLENTY OF MOISTURE WILL BE AVAILABLE TO BOOST CAPES UP FOR THE I-25 CORRIDOR FROM AROUND PUB NORTHWARD FOR THE 2ND ROUND OF THUNDERSTORMS WHICH SPREADS OFF THE SOUTHEAST MOUNTAINS DURING THE LATE EVENING. IF THIS OCCURS...THEN HAIL TO NEAR 1 INCH IN DIAMETER ALONG WITH DAMAGING WINDS MAY BE POSSIBLE FOR KCOS AND KPUB AS WELL. WILL CONTINUE TO MONITOR THIS POTENTIAL AS SCENARIO EVOLVES. ACROSS THE REMAINDER OF THE AREA...WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS AFTERNOON WITH SNOW LEVELS DROPPING ACROSS THE MOUNTAINS DURING THE EVENING WHEN BEST FORCING WITH UPPER LEVEL SYSTEM MOVES THROUGH. COULD SEE ANYWHERE FROM 2 TO 6 INCHES OF SNOW ACROSS THE HIGHER PEAKS...WITH MAJORITY OF SNOWFALL ABOVE 10KFT. PRECIPITATION WILL LIFT OFF TO THE NORTHEAST WITH THE PARENT UPPER LOW ON FRIDAY WITH PRECIPITATION TAILING OFF ACROSS THE OROGRAPHICALLY FAVORED NORTHWEST FACING SLOPES OF THE SAWATCH AND MOSQUITOS IN THE MORNING. COULD ALSO SEE A PERIOD OF WRAP AROUND PCPN ACROSS THE SOUTHEAST PLAINS DURING THE EARLY MORNING...BUT THIS SHOULD DIMINISH BY AFTERNOON. OTHERWISE...COOLER TEMPERATURES FOR FRIDAY...THOUGH WITH GUSTY NORTHWEST TO WEST WINDS BEHIND THE DEPARTING SYSTEM...DEEP MIXING WILL OFFSET THE COOLING ALOFT SOME TO STILL YIELD TEMPS IN THE 70S. -KT .LONG TERM... (FRIDAY NIGHT THROUGH THURSDAY) FRIDAY NIGHT AND SATURDAY NIGHT...CLOSED UPPER LOW OVER NORTHWEST WYOMING EARLY FRIDAY EVENING MEANDERS INTO THE WESTERN DAKOTAS THROUGH SATURDAY NIGHT. AT THE SURFACE...UPSLOPE FLOW CONTINUES ON THE SOUTHEAST CO PLAINS. NAM BREAKS OUT PRECIPITATION ALONG THE SOUTHEAST MOUNTAINS SATURDAY EVENING...BUT THEN PRECIPITATION AREAS SHIFT INTO NORTHEAST COLORADO AND FAR SOUTHEASTERN CO. GFS DOESN`T HAVE MUCH QPF OVER THE MOUNTAINS...BUT HIGHLIGHTS NORTHEAST AND FAR SOUTHEAST CORNER OF THE STATE LATE SATURDAY EVENING. GIVEN THE UPSLOPE FLOW...COOL AIR ALOFT AND STEEP LAPSE RATES...KEPT SOME LOW POPS IN ALONG THE MOUNTAINS AND SPREAD EASTWARD ONTO THE PLAINS SATURDAY NIGHT. TEMPERATURES SATURDAY SHOULD BE FAIRLY COOL. KEPT THE PLAINS IN THE MID 50S TO MID 60S FOR HIGHS DESPITE A LARGE SPREAD IN THE GUIDANCE HIGHS. SUNDAY AND SUNDAY NIGHT...GFS/ECMWF STILL BULLISH WITH PRECIPITATION DEVELOPING ACROSS THE SOUTHEAST PLAINS SUNDAY EVENING WITH SHORT WAVE MOVING ACROSS SOUTHERN COLORADO. NOT AS COOL WITH HIGHS WARMING INTO THE LOWER 60S TO LOWER 70S ON THE PLAINS. MONDAY-TUESDAY...GFS/ECMWF BOTH CONTINUE TO SHOW WEST TO SOUTHWEST FLOW ALOFT OVER COLORADO EARLY IN THE WORK WEEK AHEAD OF A STRONGER TROF PROGGED TO MOVE THROUGH WY WEDNESDAY. DESPITE WARMER AND DRIER AIR MOVING INTO THE FORECAST AREA...MODELS SHOW SOME MID LEVEL MOISTURE AND A FEW WEAK WAVES TRIGGERING SHOWERS/THUNDERSTORMS OVER THE MOUNTAINS. WEDNESDAY-THURSDAY...UPPER LEVEL SHORTWAVE TROF MOVES EAST ACROSS WY WEDNESDAY. AT THE SURFACE...COLD FRONT MOVES SOUTHEAST THROUGH THE PLAINS WEDNESDAY NIGHT. DRY LOW LEVEL AIRMASS ON THE PLAINS KEEPS SHOWER ACTIVITY TIED TO THE MOUNTAINS. TROF AXIS SHIFTS EAST INTO THE PLAINS STATES WITH RIDGE BUILDING OVER CO ON THURSDAY. STARK && .AVIATION... A COUPLE OF ROUNDS OF -TSRA MAY AFFECT KCOS AND KPUB TAF SITES...ONE LATE THIS AFTERNOON...AND ANOTHER DURING THE EVENING AS THE POTENT UPPER LEVEL STORM SYSTEM MOVES THROUGH THE REGION. FIRST ROUND OF THUNDERSTORMS WILL PRODUCE ERRATIC GUSTY WINDS UP TO 40 KTS...ALONG WITH LIGHTNING AND BRIEF HEAVY RAINFALL. THE 2ND ROUND WHICH WILL SPREAD OFF THE MTNS INTO THE TAF SITES AROUND/AFTER 02Z...COULD BE STRONGER WITH THE POTENTIAL TO PRODUCE SOME SMALL HAIL UP TO 1 INCH IN DIAMETER AS WELL AS GUSTY ERRATIC WINDS. THUNDERSTORMS SHOULD END FOR BOTH KPUB AND KCOS AROUND 06Z WITH NORTH WINDS GUSTING TO 25 TO 30 KTS. BEST WINDOW FOR -TSRA AT KALS WILL BE FROM 01Z-04Z...WITH A ROUND OF GUSTY WINDS...AND LIGHTNING AND BRIEF MODERATE RAINFALL THE MAIN THREATS. MTN AREAS WILL SEE WIDESPREAD MTN OBSCURATIONS THROUGH THE EVENING WITH POTENTIAL FOR 2-6 INCHES OF SNOW DURING THE OVERNIGHT HOURS ACROSS THE HIGHER PEAKS. GUSTY NORTH TO NW WINDS WILL CONTINUE AT THE TAF SITES THROUGH FRIDAY...WITH VFR CONDITIONS. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31/40
AREA FORECAST DISCUSSION
NWS DENVER CO
1005 AM MDT THU APR 26 2012 .UPDATE...FIRST WAVE EXITING NORTHEAST COLORADO WITH SCATTERED CONVECTION OVER THE NORTHEASET CORNER. NEXT WAVE SHOWING UP IN NORTHWEST ARIZONA WITH SOME LIGHTNING.. DRY CONDITIONS IN BETWEEN SYSTEMS WITH MAINLY SCATTERED CLOUDS OVER MOUNTAINS AND URBAN CORRIDOR. LATEST RUC SHOWS NEXT WAVE REACHING 4 CORNERS AROUND 00Z WITH INCREASING QG ASCENT AND INSTABILITY SPREADING NORTHEAST INTO CFWA. SHOULD SEE SOME CONVECTION REDEVELOPING ACROSS MOUNTAINS BY THE AFTERNOON...SPREADING ACROSS PLAINS DURING THE AFTERNOON. CAPES INITIALLY NOT ALL THAT IMPRESSIVE...GENERALLY UNDER 1000 J/KG. STILL POTENTIAL FOR SOME SMALL HAIL AND GUSTY WINDS WITH THE STORMS THIS AFTERNOON. BEST CHANCE FOR SEVERE STILL LOOKING ALONG AND EAST OF A FORT MORGAN TO LIMON LINE THIS EVENING WHEN LOW LEVEL SOUTHEASTERLIES WILL BE CRANKING AND INCREASING THE SHEAR WITH POTENTIAL FOR A FEW TORNADOES. OVERALL CURRENT FORECASTS SEEM ON TRACK...WILL MAKE MINOR ADJUSTMENTS TO CURRENT CONDITIONS. && .AVIATION...WINDS A BIT MORE SOUTHERLY BEHIND EXITING SYSTEM...SHOULD SHIFT TO THE SOUTHEAST AS LOW LEVEL WINDS INCREASE AHEAD OF APPROACHING TROUGH. SCATTERED SHOWERS AND STORMS TO BEGIN DEVELOPING OVER MOUNTAINS BY THE AFTERNOON...SPREADING ACROSS THE DENVER AREA DURING THE AFTERNOON. CURRENT TAF TRENDS STILL LOOKING ON TRACK...WITH FIRST BATCH OF STORMS AROUND 20Z THEN ANOTHER ROUND NEAR 01Z. GUSTY OUTFLOW WINDS TO 40 KTS STILL POSSIBLE WITH THE STORMS. VFR CONDITIONS TO PREVAIL...THOUGH CEILINGS AROUND 7000 FEET AGL POSSIBLE. && .HYDROLOGY...SHOWERS AND STORMS POSSIBLE ACROSS MOUNTAINS AND FOOTHILLS THOUGH THIS EVENING...CAPABLE OF PRODUCING RAINFALL AMOUNTS OF UP TO A QUARTER OF AN INCH IN 30 MINUTES OR LESS. STORMS ARE EXPECTED TO BE FAST MOVING...SO FLOODING IS NOT ANTICIPATED. && .PREV DISCUSSION... /ISSUED 454 AM MDT THU APR 26 2012/ SHORT TERM...AT THIS HOUR...A WEAK MID-LEVEL SHORT WAVE WAS PASSING OVER EXTREME EASTERN CO AND A SFC LOW WAS CENTERED JUST EAST OF PUEBLO. THE TWO HAVE COMBINED TO GENERATE SOME QG-LIFT AND UPSLOPE FLOW WHICH AS RESULTED IN A COUPLE BANDS OF LIGHT/MODERATE RAINFALL FROM JUST EAST OF DENVER TO THE KANSAS LINE. SHOWERS HAVE SHOWN SOME STRENGTHENING IN THE PAST HOUR AS THEY DRIFT NORTHEAST INTO DEEPER MOISTURE. AT THEIR PRESENT SPEED SHOULD SEE MOST OF THESE SHOWERS MOVING OUT OF THE FCST AREA BY 14Z THIS MORNING. BEFORE THEY DO COULD SEE A COUPLE LOW TOP T-STORMS POP UP. SYNOPTICALLY...A SHARPLY CURVED UPPER LEVEL SHORT WAVE TROUGH/LOW COMING ONSHORE IN SOUTHERN CALIFORNIA AT THIS TIME IS PROGGED TO RACE EAST-NORTHEASTWARD PASSING OVER THE 4-CORNERS AREA AROUND 00Z TODAY...AND EVENTUALLY OVER NORTHEAST COLORADO SOMETIME BETWEEN 06Z AND 09Z TONIGHT. LOOKS AS THOUGH WE COULD SEE TWO ROUNDS OF CONVECTION/T-STORM DEVELOPMENT PRIOR ITS ARRIVAL. FIRST ROUND OF STORMS EXPECTED TO FORM OVER THE MTNS AND FRONT RANGE FOOTHILLS BY EARLY THIS AFTERNOON WITH STG DAYTIME HEATING. THAT/S ASSUMING THE OVERLYING CIRRUS CLOUD SHIELD DOESN/T BECOME TOO THICK BEFORE CONVECTIVE TEMPERATURES ARE REACHED. INCREASING SWLY FLOW ALOFT SHOULD MOVE THIS CONVECTION OUT OVER THE PLAINS DURING THE AFTERNOON. DUE TO LIMITED LOW-LEVEL MOISTURE ON THE PLAINS AT THAT TIME CAPE VALUES ARE PRESUMABLY UNDER 1000 J/KG. STILL SUFFICIENT ENOUGH TO GENERATE STORM UPDRAFTS CAPABLE OF SMALL HAIL AND BRIEF MODERATE TO HEAVY RAINFALL. ABI IR 10.35U SAT LOOP SHOWS THIS DEVELOPMENT AND PROGRESSION NICELY. THIS FIRST WAVE OF STORMS LIKELY TO REACH THE EASTERN BORDER OF CO BY 00Z/TODAY. MODELS AND THE ARI SAT LOOP THEN SHOW A SECOND WAVE OF T-STORMS ASSOCIATED WITH THE UPPER TROUGH MOVING OUT OF THE CNTRL COLORADO MTNS AND ONTO THE NERN PLAINS OF CO DURING THE EVENING HOURS. BY THAT TIME...LOW LEVEL MOISTURE ON THE PLAINS SHOULD HAVE INCREASED CONSIDERABLY WITH STG S-SELY BNDRY LAYER FLOW ON THE WRN EDGE OF A 35-45KT LOW LEVEL JET ALONG THE CO/KS BORDER. LOW LEVEL SHEAR LOOKS QUITE IMPRESSIVE ON MODEL SOUNDS IN THIS AREA...BUT CAPES ONLY SLIGHTLY BETTER THAN THOSE PROGGED FOR EARLIER IN THE DAY. NEVERTHELESS...COUNTING ON AT LEAST ISOLATED SEVERE T-STORMS/ SUPERCELLS CAPABLE OF LARGE HAIL...POTENTIALLY DAMAGING WINDS AND EVEN A WEAK TORNADO OR TWO WITH FAVORABLE SHEAR PROFILE IN PLACE. BEST CHANCE FOR SVR APPEARS TO EXIST EAST OF A FORT MORGAN-TO- LIMON LINE. SPC CONVECTIVE DAY-1 OUTLOOK HAS THIS AREA IN A SLIGHT RISK. NO ARGUMENT WITH THAT. IN THE HIGH COUNTRY FALLING TEMPERATURES OVERNIGHT WITH THE PASSING TROUGH SHOULD DROP THE SNOW LEVEL TO AROUND 8500 OR 9000 FEET BY MORNING. THE HIGHER MTN RIDGES AND PASSES COULD PICK UP A FEW INCHES OF SNOW BY MORNING. AS FOR HIGH TEMPERATURES TODAY...GOING FOR MID TO UPPER 70S ON THE PLAINS AND 45 TO 60 IN THE HIGH COUNTRY...ASSUMING WE SEE ENOUGH SUNSHINE. THAT/S STILL SEVERAL DEGS ABOVE AVERAGE FOR THE DATE. LONG TERM...THE UPPER LOW WILL MOVE OVER NORTHEAST COLORADO FRIDAY MORNING THEN STRONG DRYING AND SUBSIDENCE KICKS IN BY AFTERNOON BEHIND THE LOW. THE MAIN CONCERN FOR THE FRIDAY PERIOD IS THE POTENTIAL FOR HIGH WINDS. FAIRLY DECENT QG DOWNWARD FORCING WITH THIS EJECTING LOW BUT QUESTIONABLE ON HOW STRONG THE WINDS MAY GET. THE GFS IS STRONGER THAN THE NAM BUT AT THIS TIME WILL PLAY SPEEDS JUST UNDER HIGH WIND CRITERIA. LOOKS LIKE THE STRONGEST WINDS WILL BE NEAR THE WYOMING BORDER AND THEN SPILLING OUT OVER THE NORTHEAST PLAINS. THE URBAN CORRIDOR LOOKS TO BE A BIT LIGHTER ON THE SPEEDS. ONCE THE LOW GETS ONSHORE THIS MORNING NEXT SHIFT MAY BE ABLE TO SEE IF INDEED THERE IS ENOUGH WIND TO WARRANT ANY HILITES. THE WINDS WILL BE ON THE DECLINE FRIDAY EVENING AS THE LOW PULLS FURTHER AWAY. SATURDAY WILL START OUT DRY BUT THE NEXT WAVE ROTATING AROUND THE MAIN LOW WILL MOVE INTO COLORADO SATURDAY NIGHT. OVERALL MOISTURE AND INSTABILITY LOOK MARGINAL AND WILL CONTINUE WITH SLIGHT CHANCE POPS OVER THE PLAINS FOR ALL OF SATURDAY NIGHT AND SUNDAY. FROM MONDAY THROUGH THE MIDDLE OF NEXT WEEK COLORADO WILL BE UNDER A MODERATE WESTERLY FLOW WITH WEAK RIPPLES IN THE FLOW. ENOUGH MOISTURE TO KEEP THE MENTION OF SHOWERS/STORMS IN THE FORECAST. TEMPERATURES THROUGH THE PERIOD WILL BE AROUND NORMALS OR JUST A BIT ABOVE. AVIATION...LIGHT DRAINAGE WINDS THIS MORNING BECOME SOUTHEASTERLY AND INCREASE IN SPEED THIS AFTERNOON. SCATTERED THUNDERSTORMS ARE EXPECTED TO BEGIN FORMING OVER THE HIGHER TERRAIN TO THE WEST AND SOUTHWEST OF DENVER AROUND 19Z TODAY. SOUTHWEST FLOW ALOFT WILL CARRY THESE STORMS ACROSS THE DENVER METRO AREA DURING THE AFTERNOON...SOME CAPABLE OF SMALL HAIL...FREQUENT LIGHTNING AND WIND GUSTS TO AROUND 40KTS. THIS FIRST WAVE OF STORMS IS EXPECTED TO MOVE EAST OF THE METRO AREA BY 00Z...ONLY TO BE FOLLOWED BY A SECOND WAVE OF SHOWERS AND T-STORMS WITH THE UPPER LEVEL TROUGH. THESE STORMS AREA NOT EXPECTED TO PRODUCE AS MUCH RAIN OR WIND...AT LEAST NOT UNTIL THEY MOVE FARTHER OUT ONTO THE PLAINS WHERE THE AIRMASS WILL BE FAR MORE MOIST AND UNSTABLE. CONDITIONS ARE LIKELY TO IMPROVE IN THE DENVER AREA AFTER 06Z WITH THE DEVELOP OF A DRY AND GUSTY DOWNSLOPE FLOW OFF THE FOOTHILLS. HYDROLOGY...SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL BE CAPABLE OF RAINFALL AMOUNTS UP TO A QUARTER INCH UNDER 20 MINUTES. SHOWERS THIS EVENING MAY LAY DOWN ANOTHER QUARTER INCH OF RAIN IN UNDER AN HOUR BEFORE MOVING ON. DUE THE FAIRLY FAST MOVEMENT OF THESE STORMS...FLOODING RAINFALL IS NOT ANTICIPATED IN THE BURN AREAS ALONG THE FRONT RANGE. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....ENTREKIN AVIATION...D-L
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1210 PM CDT THU APR 26 2012 .DISCUSSION... ISSUED 948 AM CDT THU APR 26 2012 LARGE AREA OF STRATOCUMULUS HAS PUSHED SOUTHWARD INTO FAR NORTHERN ILLINOIS. RUC MODEL LAYER HUMIDITY PLOT INDICATES SOME BREAKS DEVELOPING AS IT MOVES INTO CENTRAL ILLINOIS AROUND MIDDAY. ADDITIONAL DIURNAL CUMULUS EXPECTED TO FORM AROUND MIDDAY AS WELL...ALTHOUGH CU-RULE BEGINS TO ERODE THIS BY MID AFTERNOON. COLD-AIR ADVECTION WILL LIKELY HOLD TEMPERATURES STEADY EARLY THIS AFTERNOON...BEFORE BEGINNING A SLOW FALL. HAVE SENT SOME UPDATES TO THE HOURLY TEMPERATURE AND SKY GRIDS...BUT THESE DO NOT HAVE AN IMPACT ON THE WORDED FORECASTS. GEELHART && .AVIATION... ISSUED 1210 PM CDT THU APR 26 2012 DIURNAL STRATOCUMULUS HAS FORMED AHEAD OF A LARGER AREA OF BROKEN CLOUDS DESCENDING FROM NORTHERN ILLINOIS. SURFACE OBSERVATIONS THE LAST COUPLE HOURS HAS SHOWN THESE CLOUDS TO BE STEADILY RISING... SO ANY BROKEN CEILINGS WILL BE IN THE VFR RANGE. NORTHERLY WINDS TO CONTINUE GUSTING OVER 20 KNOTS AT TIMES THIS AFTERNOON...THEN DIMINISH ALONG WITH THE CLOUDS TOWARD SUNSET. WINDS WILL TREND MORE EASTERLY LATE THIS EVENING AS HIGH PRESSURE RIDGING MOVES ACROSS THE GREAT LAKES. STORM SYSTEM CURRENTLY OVER THE PLAINS WILL BEGIN TO SPREAD IN SOME HIGHER CEILINGS LATE TONIGHT AND PERSIST THROUGH FRIDAY MORNING. GEELHART && .PREV DISCUSSION... ISSUED 330 AM CDT THU APR 26 2012 SHORT TERM...TODAY THROUGH SUNDAY STRONG THUNDERSTORMS HAVE JUST PASSED SE OF CLAY COUNTY WITH BRUNT OF THUNDERSTORMS MOVING SE OF THE OHIO RIVER INTO NW KY. THESE WERE THE STRONG TO POTENTIALLY SEVERE THUNDERSTORMS THAT AFFECTED THE SW COUNTIES PAST 6 HOURS AND ARE EXITING WITH A SHORT WAVE. 1001 MB LOW PRESSURE OVER WEST CENTRAL INDIANA WITH ITS COLD FRONT EXTENDING WESTWARD TO NEAR I-72. SURFACE LOW PRESSURE WILL EXIT QUICKLY EAST INTO WESTERN PA BY NOON AND SWEEP THE COLD FRONT THRU SE IL BY MID MORNING. 1033 MB CANADIAN HIGH PRESSURE OVER NORTHERN PARTS OF SASKATCHEWAN AND MANITOBA AND RIDGING SOUTHWARD INTO THE UPPER MIDWEST WILL NOSE INTO IL BY SUNSET AND PROVIDE MOSTLY SUNNY SKIES. COOLER HIGHS TODAY RANGE FROM THE UPPER 60S FROM I-74 NE AND 70-75 SW AREAS. TEMPS WILL SLIP QUICKER THAN NORMAL LATER THIS AFTERNOON DUE TO COLD AIR ADVECTION ESPECIALLY NE AREAS. CANADIAN HIGH PRESSURE RIDGE OVER WI/IL/IN TONIGHT AND PROVIDES FAIR AND MUCH COLDER WEATHER WITH LOWS IN THE MID TO UPPER 30S. MET AND MAV GUIDANCE LOWS AT CHAMPAIGN ARE EVEN NEAR FREEZING. FREEZE WATCHES ARE POSTED NE OF CENTRAL IL OVER NORTHERN INDIANA FOR OVERNIGHT. COOLED LOWS A FEW DEGREES TONIGHT BUT DID NOT GO AS COLD AS FREEZING YET OVER EAST CENTRAL IL SINCE WINDS DO NOT TOTALLY GO LIGHT. MODELS CONTINUE SLOWER WITH RETURNING CONVECTION CHANCES FRIDAY AND LOWER POPS FRIDAY WITH DRY CONDITIONS FRIDAY MORNING WITH 20-30% CHANCE FRIDAY AFTERNOON WITH HIGHEST POPS SW AREAS FRI AFTERNOON. THIS DUE TO LOW PRESSURE EMERGING INTO THE CENTRAL PLAINS WITH A FRONTAL BOUNDARY JUST SOUTH OF MO/IL TRYING TO LIFT BACK NORTH FRIDAY NIGHT INTO SOUTHERN IL AS SURFACE LOW WEAKENS AS IT MOVES INTO SOUTHERN IL BY DAWN SAT. BEST CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS WILL BE OVERNIGHT FRI NIGHT INTO SAT MORNING. MUCH COOLER HIGHS IN THE MID 50S TO NEAR 60F FRI AND SAT OVER CENTRAL IL AND LOWER 60S IN SE IL FRI AND MID TO UPPER 60S SAT. HIGH TEMPERATURE FORECAST TRICKY OVER SE IL SAT DEPENDING ON HOW FAR NORTH WARM FRONT GETS AND WILL BE 70S IN THE WARM SECTOR OVER SOUTHERN IL ALONG AND SOUTH OF I-64. SHOWER CHANCES DIMINISH OVERNIGHT SAT NIGHT THEN DRY SUNDAY WITH STILL BELOW NORMAL HIGHS IN THE UPPER 50S AND LOWER 60S. LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY UNSETTLED WEATHER PATTERN LOOKS TO RETURN DURING THIS TIME PERIOD AND 00Z ECMWF MODEL IS FAVORED OVER THE DRIER GFS MODEL DUE TO ITS RECENT BETTER TRACK RECORD. IL BACK INTO A WSW UPPER LEVEL FLOW DURING THIS TIME WITH NEXT SHORT WAVE EJECTING NE SUNDAY NIGHT AND CHANCES OF SHOWERS AND THUNDERSTORMS. STILL LOOKS LIKE THE BEST CHANCES WILL BE MONDAY NIGHT THROUGH TUE EVENING WITH YET ANOTHER SHORT WAVE EJECTING NE FROM THE CENTRAL PLAINS. TEMPS TO WARM BACK TO ABOVE NORMAL DURING MIDDLE OF NEXT WEEK. KH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
358 PM CDT THU APR 26 2012 ...UPDATED FOR LONG TERM DISCUSSION... .SYNOPSIS... ISSUED AT 142 PM CDT THU APR 26 2012 EARLY THIS AFTERNOON...THE WATER VAPOR SATELLITE LOOP SHOWED THE CENTER OF A COMPACT AND INTENSE UPPER LOW OVER WESTERN ARIZONA. A FEW LIGHTNING STRIKES WERE NOTED JUST AHEAD OF THE INTENSE MID LEVEL POTENTIAL VORTICITY CENTER TIED TO THE LOW. SIGNIFICANT MID LEVEL DRYING ON WV LOOP WAS BEGINNING TO ADVANCE EASTWARD TOWARD WESTERN/CENTRAL NEW MEXICO. 12Z RAOB ANALYSIS REVEALED 140 TO 170 METER HEIGHT FALLS AT 500MB ACROSS FAR SOUTHERN CALIFORNIA WHEN THE LOW WAS CENTERED NEAR SAN DIEGO EARLIER THIS MORNING. IN THE LOW LEVELS...A SURFACE LOW WAS POSITIONED ALONG THE RED RIVER NEAR WICHITA FALLS, TX. THERE WAS A POOL OF SIGNIFICANT MOISTURE AT THE SURFACE IN THE EASTERLY FLOW NORTH OF THE SURFACE LOW OVER MUCH OF CENTRAL/SOUTHERN OKLAHOMA WITH 70 DEGREE DEWPOINTS COMMON AS OF MIDDAY. THE EASTERLY SURFACE WINDS WERE PULLING MID 60S DEWPOINTS AS FAR NORTHWEST AS LEFORS, TX IN THE EASTERN TEXAS PANHANDLE. THE EAST-SOUTHEAST WINDS CONTINUED TO ADVECT THIS MOISTURE NORTHWESTWARD DEEPER INTO THE PANHANDLES. && .SHORT TERM...(THIS EVENING THROUGH DAYBREAK FRIDAY) ISSUED AT 250 PM CDT THU APR 26 2012 SEVERE WEATHER TONIGHT IS THE MAIN CHALLENGE IN TERMS OF A) TIMING, B) CONVECTIVE MODE, C) MAIN HAZARDS. THE EVENT IS COMING INTO A BIT BETTER FOCUS NOW THAT THE EXPECTED BEGINNING OF THE SEVERE WX EVENT FOR SOUTHWEST KS IS 6-9 HOURS AWAY (AS OF 1930 UTC). SURFACE DEWPOINTS WILL BE INCREASING NORTHWESTWARD THROUGH THE EVENING WITH MOIST AXIS EXPECTED TO BE FROM WESTERN OKLAHOMA PANHANDLE INTO EASTERN TEXAS PANHANDLE WITH 60F ISODROSOTHERM NOSING UP INTO THE GUYMON, OK AREA BY 03Z. THIS YIELDS ABOUT 1800-2400 J/KG SBCAPE. THE STRONGEST SURFACE FORCING AT THIS TIME WILL BE JUST WEST OF THE INSTABILITY AXIS AND CONVECTION SHOULD BE ONGOING FROM SOUTHEAST COLORADO DOWN INTO THE NORTHWESTERN TEXAS PANHANDLE. AT LEAST THIS IS HOW THE LATEST RUC13 MODEL IS PLAYING THIS OUT IN THE CONVECTIVE QPF FIELDS, WHICH MAKES PHYSICAL SENSE GIVEN WHERE THE FORCING IS AT THAT TIME. THE THING THAT REALLY HAS US CONCERNED IS THE DEGREE OF SHEAR IN THE 0-1KM AGL LAYER. IN ADVANCE OF THE SMALL SCALE UPPER LOW...THE AGEOSTROPHIC RESPONSE IN THE LOW LEVELS WILL REALLY BE MAXIMIZED FROM 03-09Z TONIGHT...AND THE 0-1KM AGL HELICITY WILL EXCEED 300 M2/S2 OVER A LARGE AREA OF SOUTHWEST KANSAS. THE 0-1KM ENERGY-HELICITY INDEX WILL REACH THE 4 TO 5 LEVEL, WHICH IS EXTREMELY HIGH AND MORE THAN ENOUGH TO SUPPORT SIGNIFICANT LOW LEVEL ROTATION IN THE STRONGEST STORMS...INCLUDING TORNADOES. CONVECTIVE MODE IS THE REAL CHALLENGE. HOW LONG WILL THE SUPERCELL PHASE LAST? THE EARLY STORMS COMING OUT OF SOUTHEAST COLORADO WILL MOST LIKELY BE MORE SCATTERED WITH SOME DISTANCE STILL FROM THE STRONGEST 500-700MB COOLING AND MID LEVEL POTENTIAL VORTICITY (PV) ADVECTION. WHEN THE "WALL OF FORCING" COMES OUT WITH THE INTENSE MID LEVEL COLD ADVECTION AND PV ADVECTION...THE MODE WILL MOST LIKELY TRANSITION TO A QUASI-LINEAR CONVECTIVE SYSTEM (QLCS). WILL HAVE TO REALLY WATCH OUT FOR QLCS TORNADO EVENTS WHICH COULD BE SHORT-LIVED AND DIFFICULT TO WARN FOR WITH MUCH LEAD TIME GIVEN THE CHARACTERISTICS OF THIS TIME OF CONVECTIVE MODE AND THE ASSOCIATED LACK OF INTENSE MID LEVEL MESOCYCLONES. ANOTHER QUESTION IS HOW FAR SOUTH THIS THREAT WILL EXTEND INTO SOUTHWEST KANSAS. SEVERAL OF THE MODELS, MAINLY THE LARGER-SCALE MODELS, INDICATE FAIRLY ROBUST CONVECTIVE QPF AS FAR SOUTH AS THE OKLAHOMA BORDER BETWEEN 06-12Z. WILL PROBABLY EXTEND LIKELY POPS DOWN CLOSE TO THE OKLAHOMA BORDER GIVEN THIS. THE SEVERE WEATHER THREAT WILL CONTINUE ALL NIGHT AND THROUGH 12Z WITH THE 09-12Z THREAT AREA SHIFTING NORTHEAST TOWARD THE WAKEENEY-HAYS-LACROSSE AREAS. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 353 PM CDT THU APR 26 2012 STORM CHANCES WILL PERSIST IN CENTRAL KANSAS AROUND HAYS THROUGH 20Z SINCE THE UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE LOW WILL STILL BE IN THIS AREA THROUGH EARLY AFTERNOON. AS DISCUSSED IN THE SHORT TERM SECTION, THESE STORMS COULD BE SEVERE. IF STORMS PERSIST LONG ENOUGH FOR DAYTIME HEATING TO LEAD TO HIGHER CAPE, THEN VERY LARGE HAIL WOULD BE POSSIBLE AND POSSIBLY A TORNADO. SURFACE WINDS WILL BE STRONG BEHIND THIS SYSTEM TOMORROW. A WIND ADVISORY WAS ISSUED FOR MUCH OF SOUTHWEST KANSAS. AFTER THIS SYSTEM PASSES, THE ASSOCIATED COLD FRONT WILL PASS THROUGH KANSAS AND THEN STALL OUT ACROSS CENTRAL OKLAHOMA. THE UPSTREAM SYSTEM THAT CAUSED THE AFOREMENTIONED SYSTEM TO EJECT ACROSS THE PLAINS WILL HANG BACK OVER THE ROCKIES THROUGH SUNDAY AND MONDAY. THE ASSOCIATED JET STREAK WILL BE SITUATED ACROSS THE ROCKIES AND INTO KANSAS THROUGH THIS PERIOD. A WARM ADVECTION PATTERN WILL DEVELOP AHEAD OF THIS TROUGH. THE GFS/GEM/UKMET INDICATE QUITE A BIT OF PRECIPITATION ON THE COOL SIDE OF THE FRONT IN SOUTHWEST KANSAS. HOWEVER, THE ECMWF SCENARIO OF DEVELOPING WIDESPREAD THUNDERSTORMS ALONG THE FRONT OVER OKLAHOMA AND SOUTH CENTRAL KANSAS COULD PREVENT SIGNIFICANT RAINFALL FURTHER NORTH. HOWEVER, 20-40% THUNDERSTORM CHANCES WERE MAINTAINED FROM SATURDAY NIGHT THROUGH MONDAY GIVEN THE UNCERTAINTY. CLOUDS AND POSSIBLE PRECIPITATION CHANCES TO THE NORTH OF THE FRONT WILL PROBABLY KEEP HIGH TEMPERATURES IN THE 60S TO LOWER 70S WITH LOWS IN THE 40S AND 50S. BY TUESDAY AND WEDNESDAY, THE NEXT JET STREAK WILL BE MOVING ACROSS THE ROCKIES AND APPROACHING THE CENTRAL HIGH PLAINS. FRONTOLYSIS WILL OCCUR OVER OKLAHOMA, WITH ANOTHER FRONT DEVELOPING ACROSS THE NORTHERN OR CENTRAL PLAINS. A DRYLINE AND SURFACE FRONT WILL INTERSECT SOMEWHERE ACROSS THE CENTRAL HIGH PLAINS REGION. THUNDERSTORMS CANNOT BE RULED OUT EITHER DAY AS 60F DEWPOINTS WILL BE IN PLACE AHEAD OF THE DRYLINE. IT WILL BE WARMER BY THIS TIME, WITH HIGHS IN THE UPPER 70S AND 80S AND LOWS IN THE 50S TO LOWER 60S. THE HIGHEST MINIMUM TEMPERATURES, AS IS TYPICAL, WILL BE IN SOUTH CENTRAL KANSAS WHERE DEWPOINTS WILL BE HIGHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 115 PM CDT THU APR 26 2012 STRONG TO SEVERE STORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHWEST KANSAS TONIGHT AND AFFECT DDC, GCK, AND HYS TERMINALS. TIMING OF CONVECTION IS STILL A SUBSTANTIAL CHALLENGE...BUT THE BEST THINKING AT THIS TIME IS CONVECTION AFFECTING DDC AND GCK TERMINALS FROM ROUGHLY 06-10Z AND HYS LATER ON FROM ROUGHLY 10-14Z. THERE MAY EVEN BE MORE THAN ONE ROUND OF STORMS, BUT THIS CANNOT BE FORECAST IN THE TAF AT THIS TIME. THERE IS ALSO EXPECTED TO BE A 2 TO 4 HOUR PERIOD OF SOME LOW CEILINGS IN THE IFR CATEGORY AS LOW LEVEL MOISTURE MOVES NORTHWARD DURING THE 09-12Z TIME FRAME. DRY AIR WILL THEN MOVE QUICKLY NORTHEAST AFTER DAYBREAK FRIDAY WITH FLIGHT CATEGORY BACK TO VFR DURING THE 13-15Z TIME FRAME AT GCK/DDC...BUT NOT UNTIL EARLY AFTERNOON UP AT HYS. && .PRELIMINARY POINT TEMPS/POPS... DDC 61 78 45 69 / 80 70 0 0 GCK 56 77 43 68 / 80 40 0 0 EHA 53 77 43 68 / 70 10 0 0 LBL 56 79 45 69 / 70 20 0 0 HYS 61 74 43 67 / 70 80 0 0 P28 64 83 51 71 / 40 50 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ TO 8 PM CDT /7 PM MDT/ FRIDAY FOR KSZ043>045-061>065-075>080-086>088. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...FINCH AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
308 PM CDT THU APR 26 2012 .DISCUSSION... SHORT TERM (TODAY THROUGH FRIDAY)... 19Z WATER VAPOR SHOWS A SHORTWAVE LIFTING EAST THROUGH AZ WITH A LONG WAVE TROUGH OVER THE PACIFIC NORTHWEST. MID LEVEL RIDGING REMAINS OVER THE CENTRAL PLAINS. AT THE SFC 19Z OBS SHOWED RIDGING THROUGH MUCH OF KS WITH A FRONTAL BOUNDARY NEAR THE RED RIVER VALLEY. A BAND OF LIGHT SHOWER ACTIVITY HAS SET UP WITHIN A NARROW AXIS OF ISENTROPIC UPGLIDE ACROSS CENTRAL KS. FOR THIS AFTERNOON AND THIS EVENING...THE RUC AND NAM SHOW THE NARROW AXIS OF ISENTROPIC LIFT ON THE 310K SFC GRADUALLY LIFTING NORTH AND EAST. BECAUSE OF THIS HAVE INCLUDED SOME SCATTERED SHOWERS ACROSS NORTH CENTRAL KS WERE MID LEVEL MOISTURE IS A LITTLE BETTER. THE NEXT SHIFT WILL NEED TO WATCH THE EASTWARD PROGRESSION. BUT FOR NOT THINK SHOWERS WILL HAVE A HARD TIME MOVING EAST DUE TO A LITTLE MORE DRY AIR IN THE MID LEVELS. OVERNIGHT...THE SHORTWAVE OVER AZ WILL LIFT OUT OF THE SOUTHERN ROCKIES AND MOVE INTO SOUTHERN NEB THROUGH THE DAY FRIDAY. THIS WAVE IS EXPECTED TO PROVIDE THE FORCING TO SPARK CONVECTION LATE TONIGHT AND THROUGH THE DAY FRIDAY. AT THIS POINT IT LOOKS LIKE THERE COULD BE ELEVATED CONVECTION FORM DURING THE MORNING HOURS AND LIFT ACROSS NORTHEAST KS. BOTH THE NAM AND GFS SHOW A NARROW WARM SECTOR DESTABILIZING BY THE LATE MORNING OR EARLY AFTERNOON WITH SURFACE BASED CAPES ON THE ORDER OF 1000 TO 1500 J/KG. WHILE A LITTLE ON THE MARGINAL SIDE...DEEP LAYER SHEER OF 50 KTS WOULD BE SUFFICIENT FOR STORMS IN THE WARM SECTOR TO BECOME SUPERCELLS. AT THIS POINT THE MODELS PROG THE WARM FRONT TO SET UP JUST TO THE SOUTHWEST OF THE FORECAST AREA WITH IT LIFTING NORTHEAST TOWARDS A CNK TO EMP LINE BY FRIDAY EVENING. STORMS SOUTHWEST OF THIS LINE WILL HAVE THE GREATER LIKELY HOOD OF BECOMING SEVERE. ALTHOUGH ELEVATED STORMS ACROSS NORTHEAST KS COULD ALSO HAVE HAIL WITH THEM. THERE COULD BE AN ISOLATED TORNADO THREAT ALONG THE WARM FRONT AS WELL IF A STORM WERE TO DEVIATE TO THE SOUTHEAST AND RIDE ALONG THE BOUNDARY TAPPING INTO THE GREATER HELICITY JUST NORTH OF THE BOUNDARY. WITH A CONVERGENCE IN SOLUTIONS AMONG THE MODELS...HAVE INCREASED POPS INTO THE CATEGORICAL RANGE ACROSS NORTHERN KS WHERE THE BEST FORCING IS ANTICIPATED. HAVE LIKELY POPS ACROSS EAST CENTRAL KS THINKING THAT COVERAGE OF STORMS MAY BE A LITTLE MORE BROKEN IN NATURE. FRIDAY IS ALSO EXPECTED TO BECOME WINDY AS THE SFC LOW DEEPENS TO THE WEST. THE INCREASING PRESSURE GRADIENT WILL LIKELY CAUSE EAST AND SOUTHEAST WINDS TO GUST OVER 30 MPH. LOWS TONIGHT SHOULD NOT DROP OFF AS MUCH GIVEN INCREASING CLOUD COVER AND A BETTER MIXED BOUNDARY LAYER. THINK LOWS WILL BE IN THE MID 50S TO AROUND 60 FOR MOST LOCATIONS. EXPECT A GOOD GRADIENT IN MAX TEMPS FOR TOMORROW WITH CLOUDS AND EASTERLY WINDS KEEPING HIGHS IN THE LOW 60S OVER FAR NORTHEAST KS. NEAR AND SOUTHWEST OF THE WARM FRONT...HIGHS SHOULD WARM INTO THE MID 70S. WOLTERS MID TERM (FRIDAY EVENING THROUGH SUNDAY)... BY FRIDAY EVENING MODELS AGREE ON A SIMILAR POSITION OF THE UPPER TROUGH AND SURFACE LOW ACROSS CENTRAL INTO NORTHEAST KANSAS. SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE EARLY FRIDAY EVENING BEFORE THE SYSTEM QUICKLY EXITS NORTHEAST AND A DRIER AIR MASS FILLS IN ITS PLACE WITH THE PASSAGE OF A COLD FRONT. BY SATURDAY MORNING THE FRONTAL BOUNDARY WILL STALL NORTHEAST TO SOUTHWEST OVER SOUTHERN KANSAS INTO CENTRAL OKLAHOMA. SURFACE RIDGE SETTLING OVER THE CWA SHOULD KEEP MUCH OF THE AREA STABLE AND CAPPED THROUGHOUT THE SATURDAY AFTERNOON PERIOD BEFORE ADDITIONAL SHOWERS AND A POSSIBLE THUNDERSTORM OR TWO DEVELOPS ALONG AND NORTH OF THE BOUNDARY. WHILE MUCH OF THE INSTABILITY REMAINS JUST SOUTH OF THE CWA...WOULD NOT BE SURPRISED FOR AN ISOLATED THUNDERSTORM OR TWO. BEST CHANCE FOR PRECIP ATTM APPEARS TO BE SUNDAY AFTERNOON INTO THE EVENING HOURS AS ISENTROPIC LIFT INCREASES AND THE WARM FRONT LIFTS NORTHWARD. THE COVERAGE AND SEVERITY OF ANY THUNDERSTORM STILL REMAINS UNCERTAIN AS THE MODELS DEPICT VARYING SOLUTIONS ON THE PLACEMENT OF THE WARM FRONT WITH RESPECT TO OUR AREA. HOWEVER...AMPLE MOISTURE ASSOCIATED WITH THE BOUNDARY AND THE PRESENCE OF A SHORTWAVE TROUGH PASSING THROUGH SUNDAY EVENING LEADS TO A DECENT CHANCE FOR ADDITIONAL PRECIPITATION. TEMPERATURES STILL APPEAR TO BE ON TRACK FOR SATURDAY AS CLEARER SKIES AND WEAK COLD AIR ADVECTION BEHIND THE SYSTEM SHOULD HELP RAISE HIGHS INTO THE MIDDLE AND UPPER 60S TOWARDS EAST CENTRAL KANSAS. CLOUD COVER ON SUNDAY WILL INHIBIT TEMPS TO ONLY THE LOWER 60S. EXTENDED TERM (SUNDAY EVENING THROUGH THURSDAY)... VERY UNSETTLED PATTERN FOR THE EXTENDED TERM WITH CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY. A STALLED SURFACE FRONT SUNDAY EVENING INTO EARLY NEXT WEEK WILL PROVIDE THE SURFACE CONVERGENCE ALONG WITH A SERIES OF SHORTWAVES EJECTING FROM THE MAIN TROUGH OVER THE PACIFIC NORTHWEST INTO THE CENTRAL AND NORTHERN PLAINS. MODELS ARE STILL HAVING DIFFICULTY WITH RESPECT TO THE TIMING OF EACH SHORTWAVE TROUGH TO AFFECT THE CWA COMBINED LACK OF STRONG FORCING FROM ANY FRONTAL BOUNDARIES. REGARDLESS...CONTINUOUS WARM AIR ADVECTION AND DEWPOINTS RANGING FROM THE UPPER 50S TO MIDDLE 60S SUGGEST CONTINUING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THURSDAY. SOUNDING PROFILES SHOW 0-6KM BULK SHEAR VALUES MARGINAL AROUND 35 KTS WITH MIXED LAYER MUCAPE BETWEEN 1100 AND 1500 J/KG SUGGEST ANY STORMS ABLE TO DEVELOP WILL BE ELEVATED AND COULD BE STRONG. HEAVY RAIN MAY ALSO BE LIKELY AS BOTH THE GFS AND ECMWF SHOW PWAT VALUES WELL OVER AN INCH FOR EACH PERIOD IN THE FORECAST. MAIN CONCERN WILL BE IF THE MAIN FORCING ALOFT WILL COINCIDE WITH ANY SURFACE FEATURES TO ALLOW THE STRONGER STORMS TO FORM. BESIDES THE PRECIP POSSIBILITIES...NEAR NORMAL TEMPERATURES ON MONDAY ARE EXPECTED TO GRADUALLY WARM INTO THE UPPER 70S BY THURSDAY AS THE THERMAL RIDGE AXIS STRETCHES NORTHWARD OVER THE CENTRAL PLAINS. BOWEN && .AVIATION... WITH SFC RIDGING AND RELATIVELY DRY LOW LEVELS OF THE TROPOSPHERE... EXPECT VFR CONDITIONS TO PREVAIL THROUGH THIS EVENING UNTIL CYCLOGENESIS INCREASES OVER THE CENTRAL HIGH PLAINS. THE DEEPENING SFC LOW IS EXPECTED TO INCREASE THE PRESSURE GRADIENT AND CAUSE MOISTURE TO BE LIFTED UP OVER THE SHALLOW RIDGE OF HIGH PRESSURE. BECAUSE OF THIS HAVE INTRODUCED SOME MVFR CIGS TOWARDS DAY BREAK. ADDITIONALLY INCREASING FORCING FROM THE UPPER LEVEL WAVE APPROACHING FROM THE WEST SHOULD ALLOW PRECIP TO DEVELOP. THINK THE WARM FRONT WILL REMAIN TO THE SOUTHWEST OF THE TERMINALS THROUGH 18Z FRI. SO WITH SOME INHIBITION TO CONVECTION ROOTED IN THE BOUNDARY LAYER...ONLY HAVE A VCTS FOR FRIDAY MORNING SINCE IT IS UNCERTAIN WHERE ELEVATED CONVECTION MAY GO. WOLTERS && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
252 PM CDT THU APR 26 2012 ...UPDATED SHORT TERM SECTION DISCUSSING SEVERE WEATHER TONIGHT... .SYNOPSIS... ISSUED AT 142 PM CDT THU APR 26 2012 EARLY THIS AFTERNOON...THE WATER VAPOR SATELLITE LOOP SHOWED THE CENTER OF A COMPACT AND INTENSE UPPER LOW OVER WESTERN ARIZONA. A FEW LIGHTNING STRIKES WERE NOTED JUST AHEAD OF THE INTENSE MID LEVEL POTENTIAL VORTICITY CENTER TIED TO THE LOW. SIGNIFICANT MID LEVEL DRYING ON WV LOOP WAS BEGINNING TO ADVANCE EASTWARD TOWARD WESTERN/CENTRAL NEW MEXICO. 12Z RAOB ANALYSIS REVEALED 140 TO 170 METER HEIGHT FALLS AT 500MB ACROSS FAR SOUTHERN CALIFORNIA WHEN THE LOW WAS CENTERED NEAR SAN DIEGO EARLIER THIS MORNING. IN THE LOW LEVELS...A SURFACE LOW WAS POSITIONED ALONG THE RED RIVER NEAR WICHITA FALLS, TX. THERE WAS A POOL OF SIGNIFICANT MOISTURE AT THE SURFACE IN THE EASTERLY FLOW NORTH OF THE SURFACE LOW OVER MUCH OF CENTRAL/SOUTHERN OKLAHOMA WITH 70 DEGREE DEWPOINTS COMMON AS OF MIDDAY. THE EASTERLY SURFACE WINDS WERE PULLING MID 60S DEWPOINTS AS FAR NORTHWEST AS LEFORS, TX IN THE EASTERN TEXAS PANHANDLE. THE EAST-SOUTHEAST WINDS CONTINUED TO ADVECT THIS MOISTURE NORTHWESTWARD DEEPER INTO THE PANHANDLES. && .SHORT TERM...(THIS EVENING THROUGH DAYBREAK FRIDAY) ISSUED AT 250 PM CDT THU APR 26 2012 SEVERE WEATHER TONIGHT IS THE MAIN CHALLENGE IN TERMS OF A) TIMING, B) CONVECTIVE MODE, C) MAIN HAZARDS. THE EVENT IS COMING INTO A BIT BETTER FOCUS NOW THAT THE EXPECTED BEGINNING OF THE SEVERE WX EVENT FOR SOUTHWEST KS IS 6-9 HOURS AWAY (AS OF 1930 UTC). SURFACE DEWPOINTS WILL BE INCREASING NORTHWESTWARD THROUGH THE EVENING WITH MOIST AXIS EXPECTED TO BE FROM WESTERN OKLAHOMA PANHANDLE INTO EASTERN TEXAS PANHANDLE WITH 60F ISODROSOTHERM NOSING UP INTO THE GUYMON, OK AREA BY 03Z. THIS YIELDS ABOUT 1800-2400 J/KG SBCAPE. THE STRONGEST SURFACE FORCING AT THIS TIME WILL BE JUST WEST OF THE INSTABILITY AXIS AND CONVECTION SHOULD BE ONGOING FROM SOUTHEAST COLORADO DOWN INTO THE NORTHWESTERN TEXAS PANHANDLE. AT LEAST THIS IS HOW THE LATEST RUC13 MODEL IS PLAYING THIS OUT IN THE CONVECTIVE QPF FIELDS, WHICH MAKES PHYSICAL SENSE GIVEN WHERE THE FORCING IS AT THAT TIME. THE THING THAT REALLY HAS US CONCERNED IS THE DEGREE OF SHEAR IN THE 0-1KM AGL LAYER. IN ADVANCE OF THE SMALL SCALE UPPER LOW...THE AGEOSTROPHIC RESPONSE IN THE LOW LEVELS WILL REALLY BE MAXIMIZED FROM 03-09Z TONIGHT...AND THE 0-1KM AGL HELICITY WILL EXCEED 300 M2/S2 OVER A LARGE AREA OF SOUTHWEST KANSAS. THE 0-1KM ENERGY-HELICITY INDEX WILL REACH THE 4 TO 5 LEVEL, WHICH IS EXTREMELY HIGH AND MORE THAN ENOUGH TO SUPPORT SIGNIFICANT LOW LEVEL ROTATION IN THE STRONGEST STORMS...INCLUDING TORNADOES. CONVECTIVE MODE IS THE REAL CHALLENGE. HOW LONG WILL THE SUPERCELL PHASE LAST? THE EARLY STORMS COMING OUT OF SOUTHEAST COLORADO WILL MOST LIKELY BE MORE SCATTERED WITH SOME DISTANCE STILL FROM THE STRONGEST 500-700MB COOLING AND MID LEVEL POTENTIAL VORTICITY (PV) ADVECTION. WHEN THE "WALL OF FORCING" COMES OUT WITH THE INTENSE MID LEVEL COLD ADVECTION AND PV ADVECTION...THE MODE WILL MOST LIKELY TRANSITION TO A QUASI-LINEAR CONVECTIVE SYSTEM (QLCS). WILL HAVE TO REALLY WATCH OUT FOR QLCS TORNADO EVENTS WHICH COULD BE SHORT-LIVED AND DIFFICULT TO WARN FOR WITH MUCH LEAD TIME GIVEN THE CHARACTERISTICS OF THIS TIME OF CONVECTIVE MODE AND THE ASSOCIATED LACK OF INTENSE MID LEVEL MESOCYCLONES. ANOTHER QUESTION IS HOW FAR SOUTH THIS THREAT WILL EXTEND INTO SOUTHWEST KANSAS. SEVERAL OF THE MODELS, MAINLY THE LARGER-SCALE MODELS, INDICATE FAIRLY ROBUST CONVECTIVE QPF AS FAR SOUTH AS THE OKLAHOMA BORDER BETWEEN 06-12Z. WILL PROBABLY EXTEND LIKELY POPS DOWN CLOSE TO THE OKLAHOMA BORDER GIVEN THIS. THE SEVERE WEATHER THREAT WILL CONTINUE ALL NIGHT AND THROUGH 12Z WITH THE 09-12Z THREAT AREA SHIFTING NORTHEAST TOWARD THE WAKEENEY-HAYS-LACROSSE AREAS. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 334 AM CDT THU APR 26 2012 ON FRIDAY MORNING THE NEGATIVELY TILTED SHORTWAVE TROUGH WILL BE MOVING FROM THE CENTRAL PLAINS AND INTO THE MISSOURI VALLEY BY FRIDAY EVENING. ONGOING THUNDERSTORMS SHOULD CONTINUE NORTH OF A LINE FROM SCOTT CITY TO NEAR DODGE CITY AND MEDICINE LODGE WITH THE DRYLINE AND COLD FRONT IN THE EARLY MORNING THEN ENDING AROUND HAYS IN THE AFTERNOON. HIGH TEMPERATURES FOR FRIDAY WILL RANGE FROM THE LOW TO MID 70S NORTH FA TO THE MID 80S SOUTHEAST AROUND MEDICINE LODGE. FOR SATURDAY A BROAD UPPER LEVEL TROUGH WILL SLOWLY MOVE EAST INTO THE GREAT PLAINS WITH DRY WEATHER EXPECTED INTO KANSAS. SURFACE HIGH PRESSURE WILL DOMINATE THE CENTRAL PLAINS. MORNING LOWS WILL RANGE IN THE MID 40S NORTH TO THE LOW 50S SOUTH. HIGHS WILL BE MUCH COOLER AND ONLY IN THE MID 60S TO AROUND 70. SOME HIGH LEVEL MOISTURE STREAMING ACROSS THE ROCKIES COULD CREATE ABUNDANT CIRRUS CLOUDS WITH LIMITED INSOLATION. ON SUNDAY THE UPPER LEVEL TROUGH WILL MOVE NORTHEASTWARD INTO THE NORTHERN HIGH PLAINS AND DOWN ACROSS THE CENTRAL PLAINS. MOISTURE WILL RETURN AHEAD OF THE UPPER TROUGH AS UPSLOPE WINDS DEVELOP AS PRESSURES FALL IN THE LEE OF THE ROCKIES. COULD HAVE LOTS OF STRATUS AND FOG IN THE MORNING WITH LOWS IN THE MID TO UPPER 40S. THE CLOUDY TO MOSTLY CLOUDY SKIES COULD LINGER INTO THE AFTERNOON WITH HIGHS ONLY IN THE 60S. WILL KEEP A 20 TO 40 POP GOING FOR SHOWERS AND ISOLATED THUNDER WITH THE UPPER SYSTEM AND ELEVATED CAPE INTO SUNDAY NIGHT. RAINFALL AMOUNTS COULD RANGE FROM 1/4 OF AN INCH TO AROUND AN INCH IF THE GFS VERIFIES. THE NEW ECMWF HAS LESS QPF. ON MONDAY ANOTHER UPPER LEVEL SHORTWAVE TROUGH MOVES INTO THE NORTHERN AND CENTRAL PLAINS WITH SURFACE MOISTURE CONTINUING AHEAD OF A LEE LOW AS A WARM FRONT TRIES TO RETURN NORTH FROM TEXAS. WILL KEEP A 20 TO 40 POP WEST TO EAST WITH THE BEST MOISTURE EAST. MORE MAINLY ELEVATED SHOWERS AND THUNDERSTORMS COULD DEVELOP NEAR AND NORTH OF THE WARM FRONT. MORNING LOWS WILL BE MILD AND IN THE 50S WITH AFTERNOON HIGHS NEAR 80 IN THE SOUTHWEST WITH THE WARM FRONT AND UPPER 60S FAR NORTHEAST AROUND HAYS. SHOWERS AND THUNDERSTORMS COULD LINGER INTO TUESDAY AND TUESDAY NIGHT MAINLY IN THE EAST. HIGHS ON TUESDAY SHOULD BE IN THE LOW TO MID 80S SOUTHWEST AND NEAR 80 IN THE NORTH AND EAST FA. BY WEDNESDAY ANOTHER IN A SERIES OF UPPER LEVEL TROUGHS WILL MOVE ACROSS THE PLAINS WITH THE BEST MOISTURE SCOURED OUT INTO EASTERN KANSAS. STILL COULD HAVE MORE THUNDERSTORMS AGAIN IN THE EAST IF THE ECMWF IS CORRECT. LOWS ON WEDNESDAY MORNING WILL BE MILD AND IN THE 50S AND HIGHS AROUND 80. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 115 PM CDT THU APR 26 2012 STRONG TO SEVERE STORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHWEST KANSAS TONIGHT AND AFFECT DDC, GCK, AND HYS TERMINALS. TIMING OF CONVECTION IS STILL A SUBSTANTIAL CHALLENGE...BUT THE BEST THINKING AT THIS TIME IS CONVECTION AFFECTING DDC AND GCK TERMINALS FROM ROUGHLY 06-10Z AND HYS LATER ON FROM ROUGHLY 10-14Z. THERE MAY EVEN BE MORE THAN ONE ROUND OF STORMS, BUT THIS CANNOT BE FORECAST IN THE TAF AT THIS TIME. THERE IS ALSO EXPECTED TO BE A 2 TO 4 HOUR PERIOD OF SOME LOW CEILINGS IN THE IFR CATEGORY AS LOW LEVEL MOISTURE MOVES NORTHWARD DURING THE 09-12Z TIME FRAME. DRY AIR WILL THEN MOVE QUICKLY NORTHEAST AFTER DAYBREAK FRIDAY WITH FLIGHT CATEGORY BACK TO VFR DURING THE 13-15Z TIME FRAME AT GCK/DDC...BUT NOT UNTIL EARLY AFTERNOON UP AT HYS. && .PRELIMINARY POINT TEMPS/POPS... DDC 61 82 45 69 / 50 10 0 0 GCK 56 78 43 68 / 50 10 0 0 EHA 53 80 43 68 / 30 10 0 0 LBL 56 82 45 69 / 30 10 0 0 HYS 61 74 43 67 / 70 70 0 0 P28 64 85 51 71 / 40 30 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ TO 8 PM CDT /7 PM MDT/ FRIDAY FOR KSZ043>045-061>065-075>080-086>088. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...KRUSE AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
100 PM EDT THU APR 26 2012 .Forecast Update... Issued at 1000 AM EDT Apr 26 2012 Today`s forecast challenge will be to see if another round of thunderstorms fires up out ahead of the slow eastbound cold front currently draped over eastern Kentucky. As the pre-dawn convection continues to move out over the Appalachians, a stable atmosphere took over central Kentucky and southern Indiana in its wake. However, mesoscale models are indicating a refire of the convection over the eastern portions of the forecast area, out ahead of that cold front. This is due to continued diurnal heating and southwesterly flow allowing for warming at the surface and for CIN to diminish. The RUC shows SBCAPE values reaching up to 2000-2500 J/kg with no cap to keep it contained. Bottom line - going to have to monitor this closely as the moisture seems to be the big question right now. Model soundings as well as current WV sat imagery is indicating dry air aloft pushing into the region. Issued at 650 AM EDT Apr 26 2012 Have trimmed back the Severe Thunderstorm Watch some more this morning. Removed all the counties except for the far southeastern CWA where we have seen some renewed convection in the wake of the stronger line. These storms will move out of the area during the next hour. Beyond this morning, we will continue the mention for some shower/thunderstorms over the eastern portion of the forecast area through the afternoon hours. Issued at 600 AM EDT Apr 26 2012 The strongest thunderstorms this morning continue to move south and east across south central Kentucky. Have cancelled a large portion of the watch this morning. Have kept the watch out over the Bluegrass as there are a few stronger storms just to the north of the forecast area. However, any severe weather should be isolated at best. .Short Term (Today through Friday)... Issued at 350 AM EDT Apr 26 2012 The immediate concern this morning is the strong to severe thunderstorms moving into the northwestern portion of the forecast area. The isolated earlier storms have congealed into a larger bowing MCS. Relatively warm temperatures and a strong shortwave have contributed to the enhancement of this system. These storms are expected to continue to remain strong as they track east across the forecast area. We have therefore expanded the Severe Thunderstorm Watch across most of the forecast area this morning. This watch goes through 13Z, with most of the storms expected to be exiting to the east by this time. Large hail will still be a concern with these storms. However, the wind threat is increasing as a bowing line develops and winds may become the main concern as the system moves east. For the rest of the day, rain chances will rapidly decrease. We may have some lingering showers or thunderstorms across east central Kentucky through the afternoon hours. There is a bit of uncertainty however as the atmosphere should be fairly worked over in the wake of this morning`s convection. Winds will shift this afternoon as the cold front moves through. Winds are expected to become gusty ahead of and behind this front. Gusts of 20-25 mph can be expected through the late morning and afternoon hours. Highs today will be in the mid 70s north to the upper 70s in the south. We will dry out tonight as the cold front sinks south of the area. Skies will become partly cloudy to mostly clear with temperatures dropping into the lower 40s in the north to the lower 50s in the south. For Friday, the front to the south of the region will begin to move back to the north as a warm front. Ahead of this front, clouds will overspread the area. We should remain dry through mid day. Showers and thunderstorms will then begin to move in from the southwest. Think that coverage in the afternoon will be fairly limited, so have reduced pops for tomorrow into the low chance range. .Long Term (Friday Night through Wednesday)... Issued at 251 AM EDT Apr 26 2012 Friday Night through Sunday Night... Combination and of deterministic and ensemble guidance continues to show a bit of spread throughout the long term forecast period. In general, this will result in lower than normal forecast confidence. Upper air pattern over the eastern third of the US will remain generally zonal in nature with multiple short waves moving through within the mean flow. So we`ll likely see heights rising and lowering during the period with chances of precipitation occurring as each wave passes through. Previous forecast still looks fairly good compared to this evening`s model runs. Stalled out frontal boundary to the south will likely lift back northward as a warm front Friday evening as an area of low pressure moves out of the Plains and into the upper Midwest. Just how far north this front will lift northward on Saturday is still quite questionable. This will lead to a large gradient of temperatures across the region. We could see as much as a 15-20 degree gradient from south to north with highs in the lower 60s in the north and readings in the upper 70s to the lower 80s in the south. The front looks to sag back south of the area on Sunday resulting a slightly drier forecast for now. Highs Sunday will range from the lower 60s in the north tot he upper 60s to around 70 in the south...with overnight lows dropping into the upper 40s to the lower 50s. Monday through Wednesday... Did not make many changes through this period given the wide spreads in both the deterministic and ensemble guidance. The Ohio Valley looks to remain in a baroclinic zone through the period as a surface frontal boundary remains near the area. This boundary will start off to the south of the area at the beginning of the period and gradually lift northward once again. As multiple mid-level waves aloft scoot past, they will likely result in off and showers and storms. The predictability of the timing of these waves is quite low...thus plan on leaving low chance PoPs in the forecast throughout the period for now. It does appear that the front will likely lift north of the Ohio Valley toward the end of the period resulting in drier and warmer conditions as we head toward the end of the workweek. Highs Mon/Tue should warm into the 70s with upper 70s to the lower 80s returning by Wednesday. Overnight lows will generally be in the 50-60s. && .Aviation (18Z TAF Issuance)... Updated at 100 PM EDT Apr 26 2012 A CU field has been growing over the last few hours, causing most area terminals to go MVFR. This cloud cover is expected to continue to grow in coverage out ahead of an approaching cold front, currently running along the Ohio River and out toward southwestern Kentucky. A possibility exists for these clouds to grow into thunderstorms later this afternoon into the early evening hours as the atmosphere continues to destabilize under a warm, moist air mass. Aviation interests in southern Indiana should be in the clear but chances increase traveling southward, especially along the Tennessee border. Once the sun sets and the cold front passes through, VFR conditions can be anticipated through early tomorrow afternoon. There will be another increased chance for thunderstorms to develop again near the Tennessee border by later in the day on Friday. The only other concern for the rest of today would be the increasing winds/gusts as they shift from out of the southwest to the northwest after the frontal passage. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........LG Short Term.......EER Long Term........MJ Aviation.........LG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
634 PM EDT THU APR 26 2012 .SYNOPSIS... A COLD FRONT CROSSES THE AREA TONIGHT...THEN STALLS ACROSS THE CAROLINAS FRIDAY. HIGH PRESSURE BUILDS IN FROM THE NORTH FRIDAY. THE FRONT MOVES BACK NORTH AS A WARM FRONT SATURDAY MORNING... THEN STALLS ACROSS THE MID ATLANTIC REGION THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... FINAL BATCH OF PRECIP ASSOCIATED WITH MCV PUSHING OFFSHORE AS OF 22Z. EXPECT DRY CONDS IN MOST AREAS FOR THE REMAINDER OF THE NIGHT. STILL INCLUDED SLGT CHC FOR SH/TSTM THRU MIDNGT...BULK OF UPSTREAM ACTIVITY OVER EXTREME W VA IS NOT EXPECTED TO MAKE IT INTO THE WAKEFIELD CWA THOUGH LATEST HRRR AND RUC13 SHOW THE POSSIBILITY OF SOME PRECIP THIS EVNG. OTW...EXPECT DECREASING CLOUDINESS AS COLD FRNT PUSHES THRU THE AREA LATE OVRNGT. LOWS U40S-M50S. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... BOUNDARY PROGGED TO STALL ACROSS THE CAROLINAS SATURDAY AS HIGH PRESSURE BUILDS SOUTH ACROSS THE AREA. EXPECT A DRY DAY WITH A N-NW WIND BECOMING BREEZY AT TIMES (15-25 MPH). LOADED THE MIXED LAYERED DEW POINTS INTO THE GRIDS WHICH RESULTS IN RH VALUES BTWN 20-30 PERCENT DURING PEAK HEATING HOURS. GIVEN TODAYS RAINFALL... EXPECT THE FUEL MOISTURES TO STAY ELEVATED. HIGHS 60-65 EASTERN SHORE AREAS TO ARND 70 ACROSS THE PIEDMONT. FORECAST CONTINUES TO BE RATHER CHALLENGING FOR THE REST OF THE WEEKEND GIVEN THE DIFFERENT SOLUTIONS TO WHERE THE FRONTAL BOUNDARY ACTUALLY ENDS UP. CLOUDS INCREASE FRI NIGHT AS BOUNDARY BEGINS TO APPROACH FROM THE SOUTH. SOME WEAK H85 ADVECTION NOTED ACROSS WESTERN COUNTIES SO KEPT SLGHT CHC POPS THERE AFTER MIDNITE. LOWS MAINLY IN THE 40S...HOWEVER EXPECT ENOUGH CLR SKIES ACROSS THE EASTERN SHORE FOR TEMPS TO DROP INTO THE M-U30S IVOF SBY WITH STEADY TEMPS AFTER THAT. LATEST SUITE OF GUIDANCE SUPPORTS AT LEAST A CHC POPS ALL AREAS SAT AS BOUNDARY PROGGED TO STALL ACROSS THE REGION. TEMPS TRICKY AS A POTENTIAL IN-SITU WEDGE SCANARIO SETTING UP ACROSS THE PIEDMONT WHERE TEMPS MAY BE HARD PRESSED TO GET MUCH ABOVE 60...RANGING TO BTWN 65-70 SOUTH OF THE FRONT. KEPT CHC POPS SAT NIGHT TAPERING OFF TO SLGHT CHC ACROSS SOUTHERN AREAS. LOWS IN THE 40S TO L50S. LINGERING MOISTURE RESULTS IN A M CLDY DAY SUNDAY. STILL CAN NOT RULE OUT A SHOWER (20 POPS IN THE GRIDS ATTM). HIGHS M-U60S. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE UPPER LEVEL LOW THAT WILL IMPACT THE WEATHER OVER THE WEEKEND MOVES OFF TO THE NORTHEAST BY SUNDAY NIGHT AND MONDAY. UPPER LEVEL RIDGING WILL TAKE OVER TOWARD MID WEEK. THE COLD FRONTAL BOUNDARY WILL EXTEND THROUGH THE CAROLINAS AT THE BEGINNING OF THE LONG TERM PERIOD. STRONG SURFACE HIGH NORTH OF THE GREAT LAKES WILL RIDGE SOUTH THROUGH THE MID ATLANTIC STATES AND PUSH THE COLD FRONT INTO NORTHERN GEORGIA. IN THE MEANTIME...LOW PRESSURE WILL DEVELOP OVER THE MISSISSIPPI VALLEY AND HEAD E/NE THROUGH THE OHIO VALLEY TO NORTHERN PORTIONS OF THE MID ATLANTIC STATES. THIS WILL BRING THE FRONT BACK TO THE NORTH OF OUR AREA... INCREASING BOTH TEMPERATURE AND MOISTURE. UNCERTAINTY WITH THE TIMING OF ANY PCPN EXISTS FOR TUESDAY THROUGH THURSDAY. INTRODUCED CHC (30 PERCENT) SHOWERS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. UPPER LEVEL RIDGING MAY LIMIT PCPN POTENTIAL. HIGH TEMPERATURES IN THE 60S MONDAY WARM TO THE MID TO UPPER 70S (COOLER NEAR THE COAST) WEDNESDAY AND THURSDAY. LOWS AROUND 40 TO THE MID 40S MONDAY MORNING WARM TO THE MID TO UPPER 50S WEDNESDAY AND THURSDAY MORNINGS. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... A WEAKENING MESOSCALE CONVECTIVE VORTICITY MAX IS MOVING ACROSS THE AREA THIS AFTERNOON. THIS IS BEING ACCOMPANIED WITH SOME SHOWERS AND MAY EVEN PRODUCE AN ISOLATED THUNDERSTORM OVER NORTHEAST NORTH CAROLINA TO SOUTHEAST VIRGINIA. THIS WILL BE EAST OF THE AREA BY LATE AFTERNOON. A WARM FRONT IS MOVING SLOWLY NORTH AND TO THE NORTH OF IT FROM RIC TO SBY ARE AREA OF IFR CEILINGS. AS THE FRONT MOVES NORTH AND WINDS BECOME MORE SOUTHWEST EXPECT CEILINGS WILL LIFT TO MVFR TO VFR RANGE OVER THE ENTIRE AREA. A COLD FRONT WILL CROSS THE AREA TONIGHT AND THIS WILL CLEAR THE CLOUDS OUT OF THE AREA WITH VFR CONDITIONS FOR FRIDAY INTO FRIDAY NIGHT. WINDS WILL BE BREEZY ON FRIDAY. FOR THE WEEKEND A FRONTAL BOUNDARY WILL BE NEARLY STATIONARY CLOSE TO THE AREA WITH LOWS MOVING ALONG IT PROVIDING MVFR TO IFR CONDITIONS. && .MARINE... WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA UNTIL A COLD FRONTAL PASSAGE SHORTLY AFTER MIDNIGHT. N/NW WINDS INCREASE QUICKLY FROM NORTH TO SOUTH ACROSS THE WATERS AS A COLD SWEEPS THROUGH. A SCA IS IN EFFECT FOR ALL THE WATERS FROM 05 TO 18Z. SOME FINE TUNING FOR ENDING TIMES MAY BE NEEDED DURING FUTURE SHIFTS. A BROAD NORTHERLY FETCH IN THE OFFSHORE WATERS MAY PRODUCE 5 FT SEAS IN THE OUTER PORTIONS OF THE COASTAL ZONES ON SUNDAY. OTHERWISE NO MARINE ISSUES ARE CURRENTLY FORECAST BEYOND THE NW SURGE THAT OCCURS OVERNIGHT AND FRIDAY. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 2 PM EDT FRIDAY FOR ANZ630>638-650-652-654-656-658. && $$ SYNOPSIS...MPR NEAR TERM...MPR/MAS SHORT TERM...MPR LONG TERM...LSA AVIATION...JAB MARINE...LSA
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
336 PM EDT THU APR 26 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA THIS EVENING AND BRING THE CHANCE OF SHOWERS TO THE AREA. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA DRY THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH FRIDAY/... A SURFACE LOW IS CENTERED ALONG OHIO/PA BORDER WITH A POORLY DEFINED WARM FRONT EXTENDING EASTWARD ACROSS PA. WITH THE WARM FRONT PUSHING INTO THE AREA. WEAK ISNETROPIC UPLIFT IN THE WARM SECTOR AHEAD OF THE LOW IS ALLOWING FOR SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS TO MOVE ACROSS THE AREA. THE LOW WILL SHIFT EAST OF THE AREA TONIGHT WITH COOLER, CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH. GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE LOWER 30S ACROSS THE EASTERN RIDGES. A FREEZE WARNING HAS BEEN ISSUED FOR THE EASTERN RIDGES ALONG WITH FOREST COUNTY. THERE IS OPERATIONAL MODEL AGREEMENT THAT LOW-LEVEL MOISTURE WILL SHIFT EAST OF THE AREA FRIDAY MORNING WITH THE SURFACE HIGH MOVING FROM THE MIDWEST INTO THE OHIO VALLEY. A FEW DIURNAL CU MAY DEVELOP DURING THE DAY FRIDAY, ALTHOUGH SUBSIDENCE ABOVE 800MB WILL ALLOW FOR MOSTLY SUNNY SKIES. TEMPS ARE CLOSEST TO A MAV/MET BLEND, RANGING FROM NEAR 50 ALONG THE I-80 CORRIDOR AND EASTERN RIDGES TO THE THE UPPER 50S IN PORTIONS OF EASTERN OHIO. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... GFS/ECMWF INDICATE A FRONTAL BOUNDARY PULLING FROM THE TN VALLEY NORTHWARD INTO THE OH VALLEY FRIDAY NIGHT INTO SATURDAY. THE FRONTAL BOUNDARY IS PROGGED TO MAKE IT AS FAR NORTH AS NORTH-CENTRAL WV BEFORE RETREATING BACK SOUTHWARD SATURDAY NIGHT. THE NAM12 DEPICTS A WEAK LOW RIDING ALONG THE BOUNDARY WITH THE MORE COARSE GFS/ECMWF SOLUTIONS WASHING THIS FEATURE OUT. GFS INDICATES WEAK LIFT PUSHING NORTH OF THE BOUNDARY, AND THUS HAVE LIKELY POPS CLOSEST TO THE BOUNDARY IN N-CNTRL WV AND CHANCE POPS ELSEWHERE ON SATURDAY. IF THE NORTHERN EXTENT OF PRECIP CAN MAKE IT TO THE I-80 CORRIDOR, 1000-500MB THICKNESSES 5400M LINE SHOULD BE JUST NORTH AND THUS PRECIP IS FORECAST TO BE ALL RAIN. WEAK RIDGING WILL APPROACH FROM THE WEST WITH HIGH PRESSURE BUILDING IN FROM THE NORTHWEST ON SUNDAY. THIS WILL ALLOW FOR A DRY DAY. TEMPERATURE FORECAST IS A BIT CHALLENGING, DEPENDING ON THE NORTHWARD EXTENT OF THE STRONG THERMAL GRADIENT ALONG THE BOUNDARY. GIVEN THAT THE BOUNDARY IS PROGGED TO MOSTLY REMAIN SOUTH OF THE AREA, TEMPS ARE FORECAST TO BE QUITE COOL, AROUND 15-20 DEGREES BELOW NORMAL ON SATURDAY. ABUNDANT SUNSHINE ON SUNDAY WILL ALLOW FOR TEMPS TO RECOVER NICELY TO 5 TO 10 DEGREES BELOW NORMAL. LOWS TEMPS WILL DROP TO NEAR OR BELOW FREEZING NORTH AND EAST OF PITTSBURGH EACH NIGHT AND MENTION OF THIS HAS BEEN ADDED TO THE HWO. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... BLEND OF RECENT ENSEMBLE MEMBERS OF HPC-PREFERRED ECMWF AND GFS MODEL OUTPUT SHOW THE UPPER LEVEL JETSTREAM EVOLVING INTO A MORE ZONAL CONFIGURATION NEXT WEEK. HENCE EXPECT TEMPERATURES THIS PERIOD TO TREND TOWARD WARMER THAN NORMAL VALUES. EXPECT MONDAY TO BE DRY, AS CANADIAN HIGH PRESSURE CENTER PASSES EAST OF THE APPALACHIAN MOUNTAINS BY AFTERNOON. ECMWF AND GFS MOS SHOW MORNING LOWS CAN BE 10 TO 15 DEGREES COLDER THAN NORMAL AND SUBFREEZING IN SOME AREAS. AFTERNOON HIGHS MAY WARM TO NEAR SEASONABLE VALUES. A LOW PRESSURE SYSTEM, COMING EAST FROM COLORADO, WILL BRING THE UPPER OHIO VALLEY SHOWERS AND POSSIBLY THUNDERSTORMS LATE TUESDAY AND WEDNESDAY. WITH THE ZONAL JETSTREAM SHIFTING NORTH BY MID WEEK, THE NEXT LOW PRESSURE SYSTEM WILL COME EAST FROM MONTANA TO PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS WEDNESDAY NIGHT AND THURSDAY. FORECASTED TEMPERATURES TO GO AS WARM AS 10 DEGREES ABOVE NORMAL LATE TUESDAY INTO THURSDAY PER BLEND OF ECMWF AND GFS MOS. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR AND NAM MODEL OUTPUT, SHOW AREAS OF MVFR STRATOCUMULUS AND SCATTERED MVFR SHOWERS ACROSS THE UPPER OHIO VALLEY, ASSOCIATED WITH THE COLD FRONTAL PASSAGE, CONTINUING INTO EVENING. POST FRONTAL SUBSIDENCE WILL DISSIPATE ANY REMAINING MVFR STRATOCUMULUS BY 04Z. SURFACE WINDS WILL BECOME NORTHWEST, WITH GUSTS TO 25 KTS, WITH THE COLD FRONTAL PASSAGE. NORTHWEST WINDS WILL DECREASE TO 10 KTS BY 04Z. DAYTIME VERTICAL MIXING DAYTIME FRIDAY WILL PRODUCE VFR CUMULUS CLOUDS AND WIND GUSTS TO 25 KTS BY AFTERNOON. .OUTLOOK...THURSDAY NIGHT THROUGH TUESDAY... EXPECT RENEWED RESTRICTIONS FRIDAY NIGHT AND SATURDAY WITH SHOWERS ASSOCIATED WITH THE EASTWARD PASSAGE OF A LOW PRESSURE SYSTEM. VFR SUNDAY INTO TUESDAY. RESTRICTIONS WILL AGAIN BE POSSIBLE LATE TUESDAY DUE TO PREFRONTAL SHOWERS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR MDZ001. OH...NONE. PA...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR PAZ009-074-076. WV...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
213 PM EDT THU APR 26 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA THIS AFTERNOON AND BRING THE CHANCE OF SHOWERS TO THE AREA UNTIL THIS EVENING. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA DRY TONIGHT THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... 18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT FOR THE LATEST RADAR AND SKY TRENDS. THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SLIDING ACROSS THE NORTHERN GREAT LAKES, LEAVING THE UPPER OHIO VALLEY IN A WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A LOW IS CENTERED IN EASTERN OHIO WITH A POORLY DEFINED WARM FRONT EXTENDING EASTWARD INTO WESTERN PA. WITH THE WARM FRONT PUSHING INTO THE AREA, WARM AIR ADVECTION HAS ALLOWED TEMPS TO WARM INTO THE 60S ACROSS MUCH OF THE AREA. ALONG AND BEHIND THE LOW, SAT WV IMAGERY INDICATES A DRY PUNCH OF AIR WITH COOLER TDS FILTERING INTO CENTRAL OHIO AND BRING AN END TO SHOWERS. THE WEAK SURFACE LOW WILL MOVE ACROSS WESTERN PA THIS AFTERNOON WITH WEAK ISENTROPIC LIFT IN WARM AIR ADVECTION AHEAD OF IT PROVIDING THE CHANCE FOR SHOWERS ACROSS THE AREA. DEEPER MOISTURE WILL SHIFT EAST OF THE AREA BEHIND THE LOW, WITH THE CHANCE OF SHOWERS DIMINISHING FROM WEST TO EAST BY 00Z. WITH SURFACE OBS TRENDING WARMER, FORECAST IS A BLEND OF THE LAMP/HRRR FOR HIGH TEMPS, REACHING THE LOWER TO MID 60S ACROSS MUCH OF THE AREA. TONIGHT...THE LOW WILL SHIFT EAST OF THE AREA WITH COOLER, CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH. GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE LOWER 30S ACROSS THE EASTERN RIDGES. WITH TEMPS FORECAST TO DROP TO MARGINALLY NEAR FREEZING AND UNCERTAINTY WITH CLOUD COVERAGE, A FREEZE WATCH REMAINS IN EFFECT FOR THE HIGHER ELEVATIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... BOUNDARY WILL PUSH SOUTH OF REGION FRIDAY AS PIECE OF COLD CANADIAN HIGH MOVES ACROSS AREA. BOUNDARY WILL QUICKLY RETURN FRIDAY NIGHT AS SHORTWAVE AND SURFACE LOW PRESSURE MOVE FROM THE CENTRAL PLAINS TO THE MID ATLANTIC STATES ALONG FRONT. RAIN WILL SPREAD NORTH ACROSS AREA SATURDAY MORNING WITH LIKELY POPS FOR THE AFTERNOON. 850MB TEMPS NEAR -2C AND BORDERLINE 1000-850MB THICKNESS MAY ALLOW FOR A BIT OF SNOW TO MIX IN AT THE START ACROSS THE NORTH AND SINCE THIS WAS ALREADY IN PREVIOUS FORECAST LEFT AS IS. SURFACE LOW EXITS OFF THE EAST COAST AND PULLS COLD FRONT SOUTH OF REGION SATURDAY NIGHT AND ANOTHER COLD CANADIAN HIGH MOVES SOUTH ACROSS THE REGION. FORECAST USED A BLEND OF THE GFS/ECMWF. TEMPERATURES WILL AVERAGE AT LEAST 10 DEGREES BELOW AVERAGE THROUGH PERIOD. && .LONG TERM /SUNDAY THROUGH THURSDAY/... COLD HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS SUNDAY WITH A WARMER DAY MONDAY WITH RETURN SOUTHERLY FLOW ON BACKSIDE OF HIGH MONDAY. ANOTHER APPROACHING WARM FRONT WILL SPREAD SCATTERED PRECIPITATION BACK INTO THE REGION TUESDAY AND WEDNESDAY. TEMPERATURES ARE FORECAST TO BE AROUND 10 DEGREES BELOW NORMAL SUNDAY...CLOSE TO NORMAL MONDAY...THEN WARM TO A FEW DEGREES ABOVE NORMAL BY WEDNESDAY. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR AND NAM MODEL OUTPUT, SHOW AREAS OF PREFRONTAL MVFR STRATOCUMULUS AND SCATTERED MVFR SHOWERS ACROSS THE UPPER OHIO VALLEY CONTINUING INTO THE AFTERNOON. EXPECT THE COLD FRONTAL PASSAGE LATE THIS AFTERNOON FOLLOWED BY A POST FRONTAL SUBSIDENCE THAT WILL DISSIPATE ANY REMAINING MVFR STRATOCUMULUS BY 04Z. SURFACE WINDS WILL BE FROM THE SOUTHWEST 10 TO 20 KTS THIS AFTERNOON, SHIFTING TO NORTHWEST, WITH GUSTS TO 25 KTS, WITH THE COLD FRONTAL PASSAGE. NORTHWEST WINDS WILL DECREASE TO 10 KTS BY 04Z. DAYTIME VERTICAL MIXING DAYTIME FRIDAY WILL PRODUCE VFR CUMULUS CLOUDS AND WIND GUSTS TO 25 KTS BY AFTERNOON. .OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... EXPECT RENEWED RESTRICTIONS FRIDAY NIGHT AND SATURDAY WITH SHOWERS ASSOCIATED WITH THE EASTWARD PASSAGE OF A LOW PRESSURE SYSTEM. VFR SUNDAY AND MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WATCH FROM 1 AM EDT FRIDAY THROUGH FRIDAY MORNING FOR MDZ001. OH...NONE. PA...FREEZE WATCH FROM 1 AM EDT FRIDAY THROUGH FRIDAY MORNING FOR PAZ074-076. WV...FREEZE WATCH FROM 1 AM EDT FRIDAY THROUGH FRIDAY MORNING FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1216 PM EDT THU APR 26 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA THIS AFTERNOON AND BRING THE CHANCE OF SHOWERS TO THE AREA UNTIL THIS EVENING. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA DRY TONIGHT THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... 15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO INCREASE TEMPS ACROSS THE AREA AND LOWER POPS ACROSS THE SOUTH. THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SLIDING ACROSS THE NORTHERN GREAT LAKES, LEAVING THE UPPER OHIO VALLEY IN A WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A LOW IS CENTERED ACROSS THE INDIANA-OHIO BORDER WITH A POORLY DEFINED WARM FRONT EXTENDING EASTWARD ACROSS OHIO AND INTO WESTERN PA. WITH THE WARM FRONT PUSHING INTO THE AREA, WARM AIR ADVECTION HAS ALLOWED TEMPS TO WARM INTO THE 50S ACROSS MUCH OF THE AREA. ALONG AND BEHIND THE LOW, SAT WV IMAGERY INDICATES A DRY PUNCH OF AIR WITH COOLER TDS FILTERING IN ITS WAKE. THE WEAK SURFACE LOW WILL MOVE INTO WESTERN PA THIS AFTERNOON WITH WEAK ISENTROPIC LIFT IN WARM AIR ADVECTION AHEAD OF IT PROVIDING THE CHANCE FOR SHOWERS ACROSS THE AREA. A SCHC OF THUNDER HAS BEEN MENTIONED ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV WITH THE RUC INDICATING MODERATE ELEVATED INSTABILITY THERE. DEEPER MOISTURE WILL SHIFT EAST OF THE AREA BEHIND THE LOW, WITH THE CHANCE OF SHOWERS DIMINISHING FROM WEST TO EAST BY 00Z. WITH SURFACE OBS TRENDING WARMER, FORECAST IS A BLEND OF THE LAMP/HRRR FOR HIGH TEMPS, REACHING THE LOWER TO MID 60S ACROSS MUCH OF THE AREA. TONIGHT...THE LOW WILL SHIFT EAST OF THE AREA WITH COOLER, CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH. GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE LOWER 30S ACROSS THE EASTERN RIDGES. WITH TEMPS FORECAST TO DROP TO MARGINALLY NEAR FREEZING AND UNCERTAINTY WITH CLOUD COVERAGE, A FREEZE WATCH REMAINS IN EFFECT FOR THE HIGHER ELEVATIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... BOUNDARY WILL PUSH SOUTH OF REGION FRIDAY AS PIECE OF COLD CANADIAN HIGH MOVES ACROSS AREA. BOUNDARY WILL QUICKLY RETURN FRIDAY NIGHT AS SHORTWAVE AND SURFACE LOW PRESSURE MOVE FROM THE CENTRAL PLAINS TO THE MID ATLANTIC STATES ALONG FRONT. RAIN WILL SPREAD NORTH ACROSS AREA SATURDAY MORNING WITH LIKELY POPS FOR THE AFTERNOON. 850MB TEMPS NEAR -2C AND BORDERLINE 1000-850MB THICKNESS MAY ALLOW FOR A BIT OF SNOW TO MIX IN AT THE START ACROSS THE NORTH AND SINCE THIS WAS ALREADY IN PREVIOUS FORECAST LEFT AS IS. SURFACE LOW EXITS OFF THE EAST COAST AND PULLS COLD FRONT SOUTH OF REGION SATURDAY NIGHT AND ANOTHER COLD CANADIAN HIGH MOVES SOUTH ACROSS THE REGION. FORECAST USED A BLEND OF THE GFS/ECMWF. TEMPERATURES WILL AVERAGE AT LEAST 10 DEGREES BELOW AVERAGE THROUGH PERIOD. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... COLD HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS SUNDAY WITH A WARMER DAY MONDAY WITH RETURN SOUTHERLY FLOW ON BACKSIDE OF HIGH MONDAY. ANOTHER APPROACHING WARM FRONT WILL SPREAD SCATTERED PRECIPITATION BACK INTO THE REGION TUESDAY AND WEDNESDAY. TEMPERATURES ARE FORECAST TO BE AROUND 10 DEGREES BELOW NORMAL SUNDAY...CLOSE TO NORMAL MONDAY...THEN WARM TO A FEW DEGREES ABOVE NORMAL BY WEDNESDAY. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR AND NAM MODEL OUTPUT, SHOW AREAS OF PREFRONTAL MVFR STRATOCUMULUS AND SCATTERED MVFR SHOWERS ACROSS THE UPPER OHIO VALLEY CONTINUING INTO THE AFTERNOON. EXPECT THE COLD FRONTAL PASSAGE LATE THIS AFTERNOON FOLLOWED BY A POST FRONTAL SUBSIDENCE THAT WILL DISSIPATE ANY REMAINING MVFR STRATOCUMULUS BY 04Z. SURFACE WINDS WILL BE FROM THE SOUTHWEST 10 TO 20 KTS THIS AFTERNOON, SHIFTING TO NORTHWEST, WITH GUSTS TO 25 KTS, WITH THE COLD FRONTAL PASSAGE. NORTHWEST WINDS WILL DECREASE TO 10 KTS BY 04Z. DAYTIME VERTICAL MIXING DAYTIME FRIDAY WILL PRODUCE VFR CUMULUS CLOUDS AND WIND GUSTS TO 25 KTS BY AFTERNOON. .OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... EXPECT RENEWED RESTRICTIONS FRIDAY NIGHT AND SATURDAY WITH SHOWERS ASSOCIATED WITH THE EASTWARD PASSAGE OF A LOW PRESSURE SYSTEM. VFR SUNDAY AND MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR MDZ001. OH...NONE. PA...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR PAZ074-076. WV...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
348 PM CDT THU APR 26 2012 .SHORT TERM...TONIGHT. THE MAIN FORECAST CONCERN TONIGHT WILL BE THE CHANCE FOR SHOWERS. THE CLOUDS WILL CONTINUE TO THICKEN THIS EVENING AS THE FIRST AREA OF LIFT MOVES ACROSS THE FORECAST AREA. THE SHORT TERM MODELS DO NOT HAVE A REAL GOOD HANDLE ON THE PRECIP FROM WESTERN NEBRASKA INTO KANSAS...ALTHOUGH MOST OF THIS IS LIGHT. THE GFS WAS DOING THE BEST AND THE 15Z SREF BETTER THAN THE 09Z SREF. THE HRRR HAS SOME PRECIP UP TO THE CWA...THEN DISSIPATES IT THIS EVENING WITH SOME INCREASE IN THE NORTHEAST PART OF THE FORECAST AREA AFTER 06Z.DUE TO THE DRY AIR IN PLACE...THERE MAY BE A FEW SHOWERS OR SPRINKLES...WITH THE BEST CHANCE FOR SOME MINOR PRECIP ACCUMULATIONS IN THE WEST OF WAYNE AND LINCOLN AND SPRINKLES FARTHER EAST. DID NOT MENTION THUNDER AS BOTH THE NAM/GFS TENDED TO KEEP THE BETTER INSTABILITY IN THE WESTERN PART OF THE CWA OR TO THE WEST TONIGHT. SOUTHEAST WINDS LOOK TO INCREASE INTO THE 15 TO 30 MPH RANGE OVERNIGHT. ZAPOTOCNY .LONG TERM...SATURDAY THROUGH THURSDAY. PRECIPIATION CHANCES WILL PROVIDE THE MAIN FORECAST CHALLENGES THROUGH THE EARLY PART OF THIS PERIOD. 500 MB CHART FROM THIS MORNING SHOWED A STRONG AND COMPACT CLOSED LOW JUST WEST OF SAN DIEGO. THIS FEATURE HAD 12 HOUR HEIGHT FALLS OF AROUND 170 METERS. IT WILL CONTINUE TO TRACK QUICKLY NORTHEAST AND SHOULD BE OVER THE EASTERN COLORADO/NORTHWEST KANSAS BORDER AREA BY 12Z FRIDAY. AS THIS FEATURE LIFTS OUT INTO THE CENTRAL PLAINS FRIDAY...EXPECT FAIRLY WIDESPREAD PRECIPITATION TO OCCUR. LOW LEVELS WILL BE SLOW TO SATURATE...WITH MAIN 850 MB MOISTURE AND INSTABILITY AXIS GENERALLY REMAINING WEST AND SOUTH OF THE FORECAST AREA. 12Z GFS SHOWED 850 DEWPOINTS REACHING 10-12 DEGREES CELSIUS IN PARTS OF SOUTHEAST NEBRASKA DURING THE DAY. CAN NOT RULE OUT A FEW STORMS INTO THAT AREA...BUT MAIN SEVERE THREAT SHOULD STAY TO OUR SOUTH FRIDAY. TEMPERATURES WILL BE COOL WITH EASTERLY WINDS...CLOUDS AND PRECIPITATION. GENERALLY STAYED BELOW MOS GUIDANCE FOR HIGHS FRIDAY. KEPT FAIRLY HIGH RAIN CHANCES FRIDAY NIGHT AND SOME THUNDERSTORMS STILL SEEM POSSIBLE IN THE EVENING...ESPECIALLY OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. FAIRLY STRONG DRYING TAKES PLACE BEHIND THE MAIN SHORTWAVE TROUGH BY LATE FRIDAY NIGHT SO EXPECT SATURDAY TO BE MOSTLY DRY. THE 12Z ECMWF AND 12Z GFS MODEL SOLUTIONS START TO DIVERGE BY SATURDAY NIGHT INTO SUNDAY. GFS IS MORE AGRESSIVE WITH PRECIPITATION SPREADING BACK INTO THE AREA FROM THE SOUTH. GENERALLY FELT THE ECMWF WAS HANDLING THE PATTERN BETTER THAN THE GFS...BUT COULD NOT RULE OUT GFS SOLUTION SO BLENDED SOME OF THAT THINKING INTO GRIDS. A DIFFERENT CLOSED LOW...ASSOCIATED WITH THE TROUGH CURRENTLY OFF THE PACIFIC NORTHWEST...WILL MOVE INTO NORTHERN WYOMING OR SOUTHERN MONTANA BY 00Z SATURDAY. THIS SHOULD TRACK EAST TOWARD THE WESTERN DAKOTAS THROUGH SATURDAY EVENING AND THEN LIFT NORTH THROUGH SUNDAY NIGHT. MAIN AFFECTS FROM THAT SHOULD STAY TO OUR WEST OR SOUTH. A WEAK TROUGH REMAINS OVER THE ROCKIES THROUGH MID WEEK...WITH SEVERAL RIPPLES IN THE FLOW MOVING OUT ACROSS OUR AREA. THE TIMING DIFFERENCES PERSIST THROUGH DAY 7. MILLER && .AVIATION... 18Z TAFS FOR KOFK...KLNK AND KOMA. VFR CONDITIONS ARE FORECAST THROUGH 27/15Z. FIRST PIECE OF ENERGY WILL LIFT ACROSS THE TAF SITES THIS AFTERNOON. MID LEVEL CLOUDS WILL BE ON THE INCREASE MOSTLY AT FL100...BUT ALSO SOME SCT-BKN AT FL050. DRY AIR SHOULD LIMIT WIDESPREAD PRECIPITATION. THERE MAY BE A FEW SPRINKLES OR SHOWERS...HOWEVER DUE TO SPOTTY NATURE HAVE NOT INCLUDED. THE STRONGER PIECE OF ENERGY WILL MOVE ACROSS THE AREA FRIDAY. DEEP MOISTURE WILL BE AVAILABLE WITH STRONGER LIFT AND MORE WIDESPREAD PRECIPITATION ALONG WITH LOWER MVFR CIGS POSSIBLE. NORTHEAST WINDS WILL BECOME EAST AT 10 TO 15KTS WITH SOME GUSTS 20 TO 25KTS. TONIGHT AFTER 06Z...EAST TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25KTS WITH GUSTS 25 TO 30KTS. MENTIONED LOW LEVEL WIND SHEAR AT KOMA AND KLNK AFT 09Z WITH 2K WINDS INCREASING TO 45 TO 55KTS. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1207 PM CDT THU APR 26 2012 .UPDATE...OVERALL NO MAJOR CHANGES FOR THE AFTERNOON UPDATE. KEPT AT LEAST A 20 PERCENT CHANCE OF LIGHT RAIN SHOWERS GOING THROUGH 00Z FOR THE ENTIRE CWA...WITH HIGHER 30-50 PERCENT CHANCES OF MEASURABLE RAIN ACROSS WESTERN COUNTIES. NEEDLESS TO SAY...THE ODDS OF SEEING MORE THAN SPRINKLES ACROSS THE MAJORITY OF THE CWA THROUGH SUNSET IS FAIRLY SLIM...ESPECIALLY IN EASTERN ZONES. LATEST HRRR STRONGLY SUGGESTS THE SEMI-DECENT COVERAGE OF LIGHT RAIN CURRENTLY EXTENDING FROM SOUTHWEST NEB TO CENTRAL KS SHOULD MAKE A PUSH NORTHEAST INTO THE CWA DURING THE NEXT SEVERAL HOURS...GENERALLY TIED TO MODEST ISENTROPIC LIFT EVIDENT ON THE 310K SURFACE PER THE 12Z NAM. HOWEVER...RADAR TRENDS SUGGEST THE HRRR MAY BE A BIT AGGRESSIVE WITH HOW QUICKLY THIS LIGHT ACTIVITY MOVES NORTHEAST. AS FOR THUNDER CHANCES...DESPITE A FEW STRIKES RECENTLY NOTED A FEW COUNTIES SOUTHWEST OF THE CWA...AND THE PRESENCE OF MAYBE UP TO A FEW HUNDRED J/KG ELEVATED MUCAPE...WILL CONTINUE TO LEAVE A FORMAL THUNDER MENTION OUT OF THE AFTERNOON GRIDS...ALTHOUGH SUPPOSE A FEW STRIKES CANNOT BE RULED OUT ESPECIALLY FAR SOUTHWEST. TEMP WISE...MADE ONLY MINOR TWEAKS TO AFTERNOON HIGHS...GENERALLY LOWERING WESTERN AREAS A FEW DEGREES UNDER THE THICKEST CLOUDS...AND RAISING FAR EASTERN COUNTIES A FEW DEGREES...WHERE QUITE A BIT OF FILTERED SUNSHINE STILL EXISTS. ALSO TRIMMED DOWN SMALL AREA OF 80+ DEGREES IN KS ZONES TO UPPER 70S...WHICH MAY STILL BE TOO WARM. EAST TO SOUTHEAST BREEZES WILL BE ON THE INCREASE THIS AFTERNOON...WITH ALL AREAS EXPECTED TO OBSERVE GUSTS AT LEAST INTO THE 20-25 MPH RANGE BY DAYS END. && .AVIATION...18Z KGRI TAF. OVERALL THEME OF PREVIOUS FORECAST REMAINS INTACT...WITH VFR VISIBILITY/CEILING PREVAILING THROUGH AT LEAST THE FIRST 12-18 HOURS OF THE PERIOD...AND THEN INCREASING CHANCES FOR AT LEAST MVFR CEILING/VSBY ALONG WITH SHOWERS/THUNDERSTORMS DURING THE LAST 6-8 HOURS OF THE PERIOD ON FRIDAY MORNING AS A COMPACT...BUT STRONG LOW PRESSURE SYSTEM ENTERS THE REGION. STARTING OFF WITH THIS AFTERNOON/THIS EVENING...A FAIRLY SOLID MID LEVEL VFR CLOUD DECK WILL REMAIN IN PLACE...BUT WITH ONLY SPOTTY COVERAGE OF LIGHT RAIN SHOWERS EXPECTED...WILL ONLY CARRY A VICINITY SHOWER MENTION FOR NOW. MUCH OF THE 00Z-10Z TIME FRAME SHOULD THEN REMAIN LARGELY PRECIPITATION FREE...BEFORE THE MAIN PUSH OF SHOWERS/STORMS OVERSPREADS THE AREA FROM THE SOUTHWEST IN THE 10Z-18Z TIME FRAME. ALTHOUGH CONFIDENCE IS LOW IN CEILING/VISIBILITY DETAILS...AT LEAST LOW-END MVFR CATEGORIES ARE ANTICIPATED. CONFIDENCE IS RATHER HIGH IN SHOWERS/STORMS OCCURRING OFF AND ON FOR SEVERAL HOURS...AND THUS HAVE ALREADY OPTED FOR THE INTRODUCTION OF TEMPO GROUPS. ALTHOUGH THE RISK FOR LARGE HAIL AND/OR DAMAGING WIND GUSTS APPEARS SMALL AT KGRI...SOME STORMS COULD CERTAINLY HAVE SMALL HAIL POTENTIAL. AS FOR SURFACE WINDS...AN EASTERLY DIRECTION WILL DOMINATE THE ENTIRE PERIOD...WITH SPEEDS INCREASING WITH TIME...AND FREQUENT GUSTS OF 25-30KT. && .PREV DISCUSSION... /ISSUED 410 AM CDT THU APR 26 2012/ SHORT TERM...TODAY THROUGH SATURDAY NIGHT. PRIMARY FORECAST CONCERN LIES WITH PRECIPITATION CHANCES...ESP TONIGHT THROUGH FRIDAY. CONDITIONS HAVE BEEN QUIET ACROSS THE CWA THROUGH THE OVERNIGHT/EARLY MORNING HOURS...WITH SATELLITE AND PROFILER DATA CONTINUING TO SHOW THE PLAINS UNDER THE INFLUENCE OF NORTHWESTERLY FLOW. WEAK RIDGING REMAINS OVER THE HIGH PLAINS...WILE A TROUGH SHIFTS EAST ACROSS THE GREAT LAKES AND MIDWEST. FURTHER WEST...THE NEXT WEATHER SYSTEM TO IMPACT THE REGION CAN BE EASILY PICKED OUT ON SATELLITE IMAGERY...A POTENT UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY MOVING ONTO THE SOUTHERN COAST OF CAL. AT THE SURFACE...SEEING A WEAK FRONTAL BOUNDARY PUSH SOUTH THROUGH THE REGION ASSOCIATED WITH HIGH PRESSURE CENTERED OVER NC CANADA...BRINGING LIGHT NORTHERLY TO VARIABLE WINDS TO THE CWA. EVEN THOUGH WE ARE TALKING A MATTER OF 12 HRS OR SO...STILL SOME UNCERTAINTY WITH PRECIPITATION CHANCES DURING THE DAYTIME HOURS TODAY. THE UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY OVER THE SRN CAL COAST WILL CONTINUE PUSHING EAST TODAY...AND BY THIS EVENING IS EXPECTED TO END UP OVER THE FOUR CORNERS REGION. OUT AHEAD OF THIS MAIN LOW...A WEAK MID LEVEL PIECE OF ENERGY IS EXPECTED TO SHIFT OUT OF THE ROCKIES...POTENTIALLY BRINGING SOME PRECIP TO PORTIONS OF THE CWA. MODELS ARENT IN THE BEST OF AGREEMENT...WITH THE LATEST NAM SHOWING ABSOLUTELY NOTHING THROUGH 00Z...WHILE OTHERS INCLUDING THE GFS/EC/HRRR SHOWING AT LEAST SOME SCT QPF AROUND...MAINLY ACROSS THE WRN HALF OF THE CWA. ENDED UP NOT MAKING NOTABLE CHANGES TO THE LOW POPS FOR TODAY...WASNT GOING TO RAISE THEM...THE OVERALL COVERAGE /IF IT HAPPENS AT ALL/ OF PRECIP SHOULD BE PRETTY SCATTERED. ALSO LEFT AS SHOWERS...MODELS CONTINUE TO SHOW INSTABILITY ACROSS THE AREA BEING PRETTY MEAGER. LOOKING AT THE SURFACE...THE MAIN AXIS OF HIGH PRESSURE OVER THE AREA THIS MORNING SLIDES EAST THROUGH THE DAY...WHILE LOW PRESSURE IS DEVELOPING OVER THE ROCKIES/HIGH PLAINS AHEAD OF THE UPPER LEVEL LOW. THIS WILL BRING WINDS GRADUALLY BECOMING MORE EAST/SOUTHEASTERLY THROUGH THE DAY...AND INCREASING IN SPEED AS THE PRESSURE GRADIENT TIGHTENS UP ACROSS THE REGION. FORECAST HIGHS FOR TODAY REMAIN IN THE 70S. BY LATE THIS AFTERNOON AND THIS EVENING...THE MAIN SFC DRYLINE BOUNDARY IS EXPECTED TO LIE THROUGH THE CENTRAL/SRN HIGH PLAINS...AND WILL BE THE INITIAL FOCUS FOR THUNDERSTORM DEVELOPMENT. MODEL TRENDS HAVE SLOWED THINGS DOWN/SHIFTED W/SW...AND KEEPS THE MAIN INSTABILITY AXIS OVER FAR SRN/WRN KS INTO OK/TX. THE MAIN QUESTION OVERNIGHT IS HOW QUICKLY ACTIVITY PUSHES INTO THE CWA. WITH THE SLOWER TREND TO THE MODELS...DID MAKE TIMING ADJUSTMENTS TO THE POPS...INCLUDING BACKING OFF FOR MOST LOCATIONS BETWEEN 00-06Z THIS EVENING. WONT BE SURPRISED IF THE DAYSHIFT NEEDS TO MAKE ADDITIONAL TWEAKS ONCE THE 12Z DATA COMES IN. AT THIS POINT...THE BEST CHANCES FOR PRECIP LOOK TO COME POST 06Z...WITH BETTER MODEL AGREEMENT SHOWING THE OVERALL COVERAGE EXPANDING ACROSS THE CWA AS ASCENT INCREASES WITH THE APPROACHING UPPER LEVEL LOW AND DEVELOPMENT OF A 40-50KT LLJ. BETTER INSTABILITY GRADUALLY MAKES ITS WAY INTO THE CWA OVERNIGHT...AND WHILE THE HIGH PLAINS LOOK TO SEE THE BETTER CHANCES FOR STRONG/SEVERE THUNDERSTORMS...CERTAINLY CANT RULE IT OUT FOR OUR CWA. BY 12Z FRIDAY...MODELS HAVE COME INTO BETTER AGREEMENT WITH THE PLACEMENT OF THE UPPER LEVEL LOW...SET UP NEAR THE NWRN KS/NERN CO BORDER. THROUGH THE DAY...THIS FEATURE SHIFTS EAST...ENDING UP OVER PORTIONS OF CTRL/ERN NEB BY THIS EVENING. THE LATEST RUNS OF A FEW OF THE MODELS ARE TRYING TO OPEN THE LOW UP AS IT SHIFTS THROUGH THE REGION...SHOWING IT STARTING TO PHASE IN WITH ANOTHER LOW PRESSURE SYSTEM MOVING INTO THE NRN ROCKIES. AS FAR AS THE SFC PATTERN GOES...THERE IS BETTER AGREEMENT SHOWING THE MAIN LOW CROSSING EAST RIGHT OVER/JUST SOUTH OF THE NEB STATE LINE...AND IS ALSO A TOUCH SLOWER. THE ACCOMPANYING FRONT GRADUALLY MAKES ITS WAY THROUGH THE CWA...STILL AFFECTING CNTRL/ERN PORTIONS OF THE CWA DURING THE AFTERNOON HOURS. STILL EXPECTING A FAIRLY NARROW BAND OF INCREASED INSTABILITY TO DEVELOP AHEAD OF THE FRONT...BUT THERE ARE DIFFERENCES WITH HOW FAR NORTH THROUGH THE CWA IT WILL EXTEND. STILL A CONCERN FOR A FEW STRONG/SEVERE THUNDERSTORMS AS THE MID/UPPER LEVEL SYSTEM PUSHES THROUGH AND WITH THE SFC LOW/FRONTS IN THE AREA...WITH THE BETTER CHANCES LOOKING TO AFFECT THE SRN HALF OF THE CWA. THE HIGH TEMPERATURE FORECAST REMAINS TRICKY...BEING DEPENDENT ON THE TIMING/LOCATION OF THE MAIN BAND OF PRECIP THROUGH THE DAY. COULD END UP WITH A 15-20 DEGREE GRADIENT ACROSS THE CWA...WITH LOWER 50S IN THE NORTHEAST WITH THE PRECIP/CLOUDS...VS LOWER 70S IN THE SOUTH WHICH COULD SEE A FEW PEAKS OF SUN DURING THE AFTERNOON. AND WITH MORNING LOWS ALREADY IN THE 50S...THOSE NORTHERN LOCATIONS LIKELY WONT SEE MUCH CHANGE IN TEMPS THROUGH THE DAY. WILL CONTINUE TO BE A BREEZY DAY...WITH E/SERLY WINDS TO START THE DAY...SWITCHING TO THE NW BEHIND THE FRONT. SUSTAINED SPEEDS OF 20+ MPH EXPECTED...AT TIMES SOME LOCATIONS COULD FLIRT WITH ADVISORY CRITERIA...WILL BE SOMETHING TO KEEP AN EYE ON. THROUGH THE EVENING HOURS...THE MAIN AREA OF PRECIP CONTINUES TO SWING E/NE...AND DIDNT MAKE BIG CHANGES TO THE 00-06Z POPS...BUT DID CUT BACK POST 06Z. EXPECTING THAT BY 09Z OR SO PRECIP WILL HAVE SHIFTED OUT OF THE CWA. KEPT THE DRY FORECAST GOING THROUGH THE DAYTIME AND EVENING HOURS ON SATURDAY...WITH THE REGION SITTING UNDER ZONAL UPPER LEVEL FLOW...DOMINATED BY A LOW PRESSURE SYSTEM SET UP OVER THE NRN ROCKIES/HIGH PLAINS. HIGH PRESSURE SETS UP OVER THE REGION BEHIND THE FRONT...WHICH WILL BRING DIMINISHING SPEEDS...AND WITH A COOLER AIR MASS IN PLACE...HIGHS ARE EXPECTED TO TOP OUT IN THE LOW/MID 60S. WILL CONTINUE TO CARRY SMALL POPS ACROSS THE WEST AFTER MIDNIGHT...AS A PIECE OF ENERGY ASSOCIATED WITH THAT MAIN UPPER LEVEL LOW PRESSURE SYSTEM SWINGS THROUGH THE AREA. LONG TERM...STARTING 12Z SUNDAY...A FAIRLY UNSETTLED WEATHER PATTERN APPEARS TO BE IN STORE FOR THE LOCAL AREA THROUGH THE EXTENDED PERIODS AS VARIABLE CHANCES FOR SHOWERS OR THUNDERSTORMS ARE POSSIBLE EACH DAY. TEMPERATURES WILL START OFF SUNDAY SEVERAL DEGREES BELOW CLIMO AS A COOL AIRMASS WILL REMAIN IN PLACE ACROSS THE REGION IN WAKE OF DEPARTING UPPER LEVEL LOW...WITH A GRADUAL WARMING TREND THEN EXPECTED THROUGH THE MIDDLE OF NEW WEEK. THROUGH THE PERIOD...A FAIRLY PROGRESSIVE WESTERLY UPPER LEVEL FLOW PATTERN APPEARS TO BE SETTING UP ACROSS THE REGION...WITH GOOD AGREEMENT AMONG BOTH THE LATEST GFS AND EC DEVELOPING THIS FLOW PATTERN. WHILE SHOWER AND THUNDERSTORM CHANCES WILL VARY GREATLY WITH TIMING OF EACH PASSING WAVE...AT THIS TIME...CHANCES APPEAR TO INCREASE EARLY NEXT WEEK AS LOW LEVEL FLOW TURNS MORE SOUTHERLY AND INCREASES DEWPOINTS ACROSS THE REGION. THIS INCREASED LOW LEVEL MOISTURE WILL AID IN CONVECTIVE INSTABILITY BY MONDAY AFTERNOON...WITH MU CAPE VALUES SURGING ACROSS THE LOCAL AREA. WHILE THE SHEAR PROFILE IS NOT IDEAL...WITH SO MUCH INSTABILITY CANNOT RULE OUT THE CHANCE OF A STRONG OR EVEN SEVERE THUNDERSTORM OVER THIS TIME PERIOD...AND CORRESPONDINGLY DECIDED TO ADVERTISE THE POTENTIAL IN MORNING HWO. WHILE CONVECTIVE POTENTIAL INCREASES BY MONDAY...WETTEST DAY ACTUALLY APPEARS TO BE SUNDAY...AS CLOUDY SKIES AND STRATIFORM PRECIP ARE EXPECTED THANKS TO A LARGE UPPER LEVEL LOW ACROSS THE NORTHERN ROCKIES AND ITS ASSOCIATED FRONTAL BOUNDARY DRAPED ACROSS THE LOCAL AREA. AT THIS TIME...INSTABILITY IS VERY LIMITED ON SUNDAY...AND DECIDED NOT TO INCLUDE THE MENTION OF THUNDERSTORM ACTIVITY UNTIL INSTABILITY INCREASES SIGNIFICANTLY ON MONDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION/UPDATE...PFANNKUCH SHORT TERM...ADO LONG TERM...ROSSI
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
321 PM EDT THU APR 26 2012 .SYNOPSIS... A COLD FRONT WILL DIP INTO THE COASTAL CAROLINAS LATE TONIGHT... STALLING FRIDAY...THEN LIFTING NORTH SATURDAY. THE FRONT WILL RETURN SOUTH LATE SATURDAY NIGHT AND FINALLY GET PUSHED OUT OF THE AREA AS CANADIAN HIGH PRESSURE SURGES SOUTH ALONG THE ATLANTIC COAST INTO MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM THURSDAY...A STRONG UPPER DISTURBANCE IS PUSHING ACROSS VIRGINIA AND NORTHERN NORTH CAROLINA THIS AFTERNOON. ALONG THE FRONT EDGE OF THIS DISTURBANCE THIS MORNING A SQUALL LINE CAME ROARING OUT OF THE MOUNTAINS BUT DIED OUT AS IT CROSSED INTERSTATE 77. THE TAIL END OF THIS UPPER DISTURBANCE HAS DEVELOPED A NEW CLUSTER OF CONVECTION THIS AFTERNOON IN THE SC SANDHILLS BACK TO JUST SOUTH OF CHARLOTTE. THESE NEW STORMS APPEARS TO BE LARGELY ELEVATED IN NATURE ALTHOUGH THEY RISK BECOMING SURFACE-BASED AS THEY MOVE INTO A MORE DEEPLY-MIXED REGION IN THE SC/NC COASTAL PLAIN WHERE DRY-ADIABATIC LAPSE RATES EXIST FROM THE SURFACE UP THROUGH AT LEAST 5500 FT. RISKS ASSOCIATED WITH THESE STORMS MAY TRANSITION FROM LIGHTNING AND HAIL TO DAMAGING WINDS. FOR THE NEXT SEVERAL HOURS WE`RE FORECASTING THIS BATCH OF STORMS TO AFFECT AREAS FROM BENNETTSVILLE AND DILLON ACROSS SOUTHERN ROBESON COUNTY...PERHAPS MAKING IT INTO THE WHITEVILLE AREA TOWARD 6 PM. POPS HAVE BEEN INCREASED TO 50-80 PERCENT IN THIS REGION FROM 3-6 PM. A SECOND UPPER DISTURBANCE IN TENNESSEE AND KENTUCKY IS EXPECTED TO FOLLOW THIS EVENING IN THE FOOTSTEPS OF OUR FIRST DISTURBANCE. CLUSTERS OF THUNDERSTORMS ACROSS E TN INTO THE NC MOUNTAINS WILL PUSH EAST AND INTO THE CENTRAL AND EASTERN CAROLINAS BY SUNSET. THE LAST FEW HRRR RUNS SHOW THIS ACTIVITY MOVING EAST ACROSS THE NORTHERN HALF OF OUR FORECAST AREA BETWEEN 7 PM AND MIDNIGHT. POPS IN THE 30-50 PERCENT RANGE ARE FORECAST ALONG AND NORTH OF A LINE FROM DARLINGTON...DILLON...WHITEVILLE AND BURGAW DURING THAT TIME FRAME. AFTER MIDNIGHT CONVECTION SHOULD PUSH EAST OF THE AREA AND BREEZY WINDS SHOULD BEGIN TO DIE DOWN AS THE PRESSURE GRADIENT RELAXES AND THE BOUNDARY LAYER BECOMES MORE STABLE. BY DAYBREAK A SYNOPTIC COLD FRONT WILL BE KNOCKING ON THE DOOR FROM THE NORTH. MODELS ARE NOT IN GOOD AGREEMENT WITH PRECISELY HOW FAR SOUTH THE BOUNDARY MOVES. THE GFS IS THE SOUTHERNMOST SOLUTION BUT DOESN`T SEEM TOO UNREASONABLE GIVEN ALL THE CONVECTION EXPECTED ACROSS NORTHERN AND CENTRAL NC TONIGHT WHICH COULD HELP PUSH THE BOUNDARY SOUTH. LOWS ARE EXPECTED TO RUN 5-10 DEGREES ABOVE NORMAL...RANGING FROM 60 INLAND TO THE MID 60S ON THE SC COAST. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 PM THURSDAY...COLD FRONT WILL BE MOVING DOWN FROM THE NORTH THROUGH OUR AREA ON FRIDAY MORNING BEFORE STALLING OUT CLOSE TO THE NC/SC BORDER BY AFTERNOON. THE SHORTWAVE DRIVING THIS FRONT SHIFTS OFF SHORE BY MID MORNING LEAVING MORE IN THE WAY OF SUBSIDENCE IN ITS WAKE. THIS FRONT WILL REMAIN BISECTING OUR CWA THROUGH FRIDAY AND WILL REMAIN THE FOCAL POINT FOR PCP. IT LOOKS LIKE THE BEST CHC OF SHWRS WILL BE IN THE MOISTURE RICH AIR TO THE SOUTH OF THE FRONT FROM THE NC/SC BORDER TO CAPE FEAR AND SOUTH OVER SC EARLIER AND MOVING NORTH LATER IN THE DAY. WITH SUBSIDENCE PRESENT EARLIER IN THE DAY...THINK WE WILL SQUEEZE OUT A DECENT MORNING OVER MOST AREAS BUT EXPECT CLOUDS AND SHWRS/TSTMS IN VICINITY OF FRONT AND BETTER CHC LATER IN DAY INTO OVERNIGHT HOURS AS NEXT SHORTWAVE MOVES THROUGH. MID TO UPPER RIDGE ALONG THE MISSISSIPPI VALLEY ON FRI WILL MOVE EAST. FLOW ALOFT BECOMES MORE PARALLEL KEEPING FRONT IN THE VICINITY THROUGH FRI BUT IT WILL MOVE BACK NORTH ON SATURDAY AS A GENERAL W-SW FLOW DEVELOPS ALOFT AS SHORTWAVE MOVES THROUGH. LATEST NAM AND GFS WERE A BIT SLOWER TO MOVE THIS BOUNDARY BACK NORTH WHICH MAY KEEP CLOUDS AND POSSIBLE PCP IN FORECAST SAT MORNING. THE SHALLOW COOL AIR WILL REMAIN INLAND AND NORTH WHILE WARMER AIR PUSHES NORTH ALONG THE COAST INITIALLY. THIS TROUGH/FRONT OVER AREA WILL MOVE NORTH SAT AFTERNOON BUT WILL GET HELD UP ONCE AGAIN JUST NORTH OF OUR AREA BY SUNDAY MORNING. OVERALL EXPECT A CLOUDIER AND WETTER SAT THAN IT LOOKED A FEW DAYS BACK. TEMPS WILL BE ANOTHER CHALLENGE. EXPECT HIGHS UP TO 10 DEGREES COOLER TO THE NORTH VS SOUTH OF FRONT. FLORENCE AREA TO COASTAL SC SHOULD BE IN THE MID 80S WHILE LUMBERTON AND THE NORTHERN TIER OF CWA WILL SEE READINGS IN THE MID 70S. OVERNIGHT LOWS WILL REMAIN WARMER WITH CLOUDS AND PCP PRESENT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY...BACK DOOR COLD FRONT CROSSES SOUTH THROUGH THE CWA SUNDAY. VERY LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH THIS FEATURE HAS PROMPTED EVEN FURTHER REDUCTION FROM INHERITED POP...WITH SCHC NOW CONFINED TO ONLY THE NORTHERN HALF OF THE AREA. IF THIS DRYING PATTERN CONTINUES...WILL LIKELY NEED TO REMOVE ANY MENTION OF SHOWERS ALTOGETHER WITH LATER UPDATES. AS THIS FRONT MOVES SOUTH...IT WILL RESTRICT MAX TEMPS TO ONLY THE MID 70S ACROSS THE NORTH...WITH LOWER 80S LIKELY IN THE FAR SOUTHWEST WHERE FROPA OCCURS LATER. VERY SIGNIFICANT MODEL DIFFERENCES EXIST NOW FOR MON/TUE WHICH CREATE LOWERED CONFIDENCE FOR THIS PART OF THE FORECAST. GFS STILL SHOWS A STRONG WEDGE OF HIGH PRESSURE HOLDING ACROSS THE CAROLINAS MONDAY INTO TUESDAY...WHILE CMC/ECMWF HAVE BACKED OFF ON THIS FEATURE. ALTHOUGH HPC CONTINUES TO FAVOR THE ECMWF...THE RECENT CONSISTENCY OF THE GFS CANNOT BE IGNORED EVEN IF IT IS THE OUTLIER NOW. ADMITTEDLY...IT IS CLIMATOLOGICALLY QUITE DIFFICULT TO GET A STRONG WEDGE THIS TIME OF YEAR SO THE ECMWF SOLUTION MAY BE MORE REALISTIC...BUT HESITATE TO MAKE ANY SIGNIFICANT CHANGES TO THIS PORTION OF THE FORECAST DUE TO UNCERTAINTY. SO WILL JUST ADJUST TEMPS UPWARD A BIT...BUT OTHERWISE LEAVE PRETTY MUCH UNCHANGED FOR NOW. BY LATE TUESDAY ANY REMNANT WEDGING...IF ANY...ERODES AS HIGH PRESSURE DRIFTS OFFSHORE AND WARM SOUTHERLY RETURN FLOW ENVELOPS THE AREA. THIS WILL BRING BACK WEATHER MORE TYPICAL OF EARLY MAY...WITH TEMPS RISING TO ABOVE CLIMO WED/THU. && .AVIATION /18Z THURSDAY THROUGH MONDAY/... AS OF 18Z...MCS IS DYING WITH MOST OF THE MOISTURE REMAINING NORTH OF THE REGION. EXPECT SCATTERED CONVECTION TO REFIRE THIS AFTERNOON. COVERAGE AND TIMING ARE STILL AN ISSUE...BUT WITH THE STEEP MID LEVEL LAPSE RATES THERE WILL LIKELY BE SOME STRONG STORMS SOMEWHERE IN THE EASTERN CAROLINAS. WE THINK THE BEST CHANCE WILL BE ACROSS NC WHERE THE HIGHEST PRECIPITABLE WATER VALUES ARE. STRONG SOUTHWEST SURFACE WINDS WILL CONTINUE THROUGH THE AFTERNOON HOURS...GUSTS TO 30 KTS LIKELY. TONIGHT...A SECONDARY ROUND OF CONVECTION IS POSSIBLE WITH A SECOND UPPER DISTURBANCE. SURFACE WINDS WILL DIMINISH BUT WILL REMAIN ABOVE 8 KTS MOST OF THE NIGHT. FRIDAY...EXPECT VFR WITH MORE OF A NORTHWESTERLY FLOW AS A POORLY DEFINED FRONT SAGS SOUTH. LOOK FOR CONVECTION TO REFIRE FRIDAY AFTERNOON. EXTENDED OUTLOOK...SCATTERED SHOWERS AND STORMS POSSIBLE FRIDAY AFTERNOON THROUGH THE EVENING HOURS. ISOLATED STORMS SATURDAY. VFR SUNDAY AND MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM THURSDAY...LOW PRESSURE IS DEEPENING ACROSS SOUTHEAST VIRGINIA THIS AFTERNOON AND SHOULD PUSH OUT INTO THE WESTERN ATLANTIC THIS EVENING. THIS LOW HAS PRODUCED A TIGHTENED PRESSURE GRADIENT BETWEEN ITSELF AND HIGH PRESSURE RIDGING WEST ACROSS THE FLORIDA PENINSULA. STRONG SOUTHWEST WINDS SHOULD GRADUALLY DIMINISH OVERNIGHT AS THE GRADIENT TIGHTENS...AND AS A COLD FRONT SLIDES SOUTH TOWARD THE REGION. THIS FRONT MAY BEGIN TO MOVE INTO THE CAPE FEAR REGION AROUND DAYBREAK FRIDAY...OTHERWISE EXPECT LARGELY SOUTHWEST WINDS TO PREVAIL OVERNIGHT. THUNDERSTORMS DEVELOPING IN THE CENTRAL AND WESTERN CAROLINAS WILL MOVE EAST AND MAY BEGIN TO AFFECT THE COASTAL WATERS MAINLY NORTH OF MYRTLE BEACH THIS EVENING. GUSTY WINDS AND LIGHTNING THE PRIMARY EXPECTED THREATS. WITH STRONG WINDS OVER THE PAST 12 HOURS HAVE DEVELOPED QUITE A ROUGH SEA STATE. SEA HEIGHTS ARE BEING MEASURED AS HIGH AS 8-9 FEET OUT AT THE FRYING PAN SHOALS BUOY...WITH 5-6 FT CLOSER TO SHORE AT THE CORMP BUOYS. SEAS WILL GRADUALLY DIMINISH OVERNIGHT AS WINDS DIE AWAY BUT IT WILL TAKE TIME. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 PM THURSDAY...COLD FRONT WILL DROP SOUTH AND STALL NEAR CAPE FEAR REMAINING DRAPED ACROSS AREA ON FRIDAY INTO SATURDAY. THIS WILL CREATE LIGHTER AND MORE VARIABLE WINDS OVER THE LOCAL WATERS. THERE WILL BE AN OVERALL DECREASE IN WINDS AND SEAS AS GRADIENT WEAKENS OVER AREA. SEAS WILL START OUT NEAR SCA BUT WILL DIMINISH QUICKLY THROUGH AFTERNOON DOWN TO 3 FT OR LESS BY LATE AFTERNOON. WINDS WILL BE N-NE VEERING AROUND TO THE E-NE NORTH OF THE FRONT AND WILL BE SOUTHERLY TO THE SOUTH OF BOUNDARY. BY SAT AFTERNOON FRONT WILL MOVE BACK NORTH AGAIN AND A SLIGHT INCREASE IN S WINDS WILL DRIVE SEAS BACK UP A BIT REACHING 3 TO 4 FT. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 300 PM THURSDAY...BACK DOOR COLD FRONT CROSSES THE WATERS SUNDAY SO WINDS WILL BE LIGHT AND VARIABLE DURING FRONTAL PASSAGE...BECOMING NE AND INCREASING TO AROUND 15 KTS LATE SUNDAY BEHIND THE FRONT. SEAS WILL BE PREDOMINANTLY 2-4 FT THROUGH MOST OF SUNDAY...BUILDING TO 3-5 FT LATE DUE TO THE INCREASING WINDS. MODERATE NE WINDS PERSIST MUCH OF MONDAY BEFORE EASING AND VEERING GRADUALLY TO THE SE TUESDAY AS HIGH PRESSURE DRIFTS OFFSHORE. SEAS STAY ELEVATED THROUGH THE FIRST HALF OF MONDAY...3-5 FT EXCEPT IN THE FAVORED SHADOW REGIONS SW OF FRYING PAN SHOALS. CAUTIONARY HEADLINES APPEAR LIKELY LATE SUNDAY INTO MONDAY...BUT CONDITIONS MAY REMAIN JUST BELOW SCA THRESHOLDS. SEAS THEN FALL BACK TO 2-4 FT LATE MONDAY AND TUESDAY WITH AN INCREASING SE SWELL. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252. && $$ NEAR TERM...TRA SHORT TERM...RGZ LONG TERM...JDW AVIATION...TRA/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1224 PM EDT THU APR 26 2012 .SYNOPSIS... ...STRONG AND GUSTY SOUTHWEST WINDS INTO THIS EVENING... STRONG LOW PRESSURE WILL PASS TO OUR NORTH TODAY...ACCOMPANIED BY STRONG WINDS. SCATTERED THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING COULD BRING EVEN STRONGER WIND GUSTS...ESPECIALLY ACROSS NORTH CAROLINA. A COLD FRONT WILL DIP INTO THE COASTAL CAROLINAS LATE TONIGHT... STALLING FRIDAY...THEN LIFTING NORTH SATURDAY. THE FRONT WILL RETURN SOUTH LATE SATURDAY NIGHT AS CANADIAN HIGH PRESSURE SURGES SOUTH ALONG THE ATLANTIC COAST INTO MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM THURSDAY...MCS/SQUALL LINE TO OUR WEST IS FALLING APART AS EARLIER FORECAST. OBSERVATIONS WITHIN THE REMNANT RAIN AREA SHOW CLOUD CEILINGS AT OR ABOVE 8500 FT AGL. IF ANY OF THE PRECIP REACHES THE GROUND IN OUR SOUTH CAROLINA PEE DEE COUNTIES ONLY A COUPLE HUNDREDTHS OF AN INCH ARE POSSIBLE GIVEN THE DEEP DRY SUB-CLOUD LAYER. NEW CONVECTION REMAINS POSSIBLE AFTER 18-19Z AS THE SURFACE CONTINUES TO WARM AND DESTABILIZE. NO SIGNIFICANT CHANGES ARE NEEDED FOR THE FORECAST EARLY THIS AFTERNOON. PREVIOUS DISCUSSION FROM 1030 AM FOLLOWS... SURFACE LOW PRESSURE IN OHIO WILL MOVE INTO NEW ENGLAND TONIGHT...AS A SECONDARY LOW DEVELOPS ACROSS VIRGINIA AND MOVES OFFSHORE THIS EVENING. BOTH OF THESE LOWS ARE THE RESULT OF UPPER DISTURBANCES: A STRONG ONE OVER LAKE SUPERIOR AND A WEAKER ONE MOVING INTO THE VIRGINIA/NC MOUNTAINS THIS MORNING. AN IMPRESSIVE SQUALL LINE ACROSS THE SOUTHERN APPALACHIANS THIS MORNING HAS PUSHED EAST OF THE MOUNTAINS AND TO INTERSTATE 77 AT THE TIME OF THIS WRITING. EVEN THE HOURLY HRRR RUNS HAVE FAILED TO KEEP UP WITH THE RAPID SOUTH AND EASTWARD MOTION OF THIS LINE. TYPICALLY WE EXPECT ORGANIZED CONVECTIVE SYSTEMS TO WEAKEN DURING THE LATE MORNING DUE TO DETERIORATION OF THE LOW-LEVEL JET AS SUNSHINE STEEPENS LOW-LEVEL LAPSE RATES AND THE MOMENTUM OF THE JET BECOMES DISTRIBUTED OVER A DEEPER LAYER DOWN TO THE SURFACE. THE HRRR SHOWS WEAKENING OF THE LINE BETWEEN NOW AND 16Z/NOON EDT...BUT STILL MAINTAINS AT LEAST SOME CONVECTIVE ACTIVITY ARRIVING IN THE BENNETTSVILLE AND LUMBERTON AREAS BY 17-18Z/1-2 PM EDT. THE ATMOSPHERE WILL BECOME MODERATELY UNSTABLE ACROSS THIS REGION WITH SURFACE-BASED CAPE RISING TO 1500 J/KG...-5 LIFTED INDICES...AND LITTLE CAPPING. FORECAST WIND PROFILES ALSO SHOW SUFFICIENT VERTICAL SHEAR FOR ORGANIZED STORMS (0-6 KM BULK SHEAR 30-40 KT). ANY ACTIVITY SHOULD MOVE EAST ACROSS INTERIOR SOUTHEAST NORTH CAROLINA DURING THE AFTERNOON...WITH DAMAGING WIND GUSTS THE PRIMARY THREAT. FARTHER SOUTH INTO SOUTH CAROLINA...A CONVECTIVE CAP BETWEEN 800-700 MB (6500-10000 FT AGL) WILL ACT TO INHIBIT STORM DEVELOPMENT AND THERE IS A MUCH LOWER CHANCE OF STORMS HERE DURING THE DAYLIGHT HOURS. EVEN THE SEABREEZE MAY NOT EXTEND HIGH ENOUGH INTO THE ATMOSPHERE TO OVERCOME THIS CAP AND WE ARE MAINTAINING A DRY FORECAST INTO LATE AFTERNOON AWAY FROM THE NORTH CAROLINA STATE LINE. VERY BREEZY CONDITIONS ARE EXPECTED TODAY DUE TO A TIGHT PRESSURE GRADIENT ALONG THE SOUTH SIDE OF THE DEVELOPING SURFACE LOW IN VIRGINIA. RADAR WIND PROFILES SHOW 50 KT WINDS AS LOW AS 4000 FT AGL...AND 30-40 KT WINDS AT 1000-2000 FT AGL. STRONG INSOLATION SHOULD STEEPEN LAPSE RATES SUFFICIENTLY TO BRING GUSTS TO 30 KT (35 MPH) TO THE SURFACE RATHER EASILY TODAY EVEN OUTSIDE OF THUNDERSTORMS. TONIGHT MODELS SHOW A SECOND UPPER DISTURBANCE DIVING SOUTHEAST ACROSS THE AREA. EARLIER STORMS ACROSS CENTRAL NORTH CAROLINA SHOULD HAVE SHARPENED UP A FRONTAL BOUNDARY WHICH MAY ACT TO PROVIDE A LITTLE STRONGER FOCUS FOR STORMS AFTER DARK. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT IN THE AREA FRI WITH THE LATEST GUIDANCE NOW STALLING THE FRONT ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA AT THE START OF THE PERIOD. FRONT SLOWLY LIFTS NORTH LATER FRI INTO FRI NIGHT AS SURFACE WAVE AND SHORTWAVE ALOFT MOVE EAST ACROSS THE AREA. FORECAST SOUNDINGS AND CROSS SECTIONS SHOW A NARROW BAND OF DEEP MOISTURE LIFTING INTO THE AREA LATE FRI NIGHT. WHILE THERE IS NO SURFACE BASED INSTABILITY TO SPEAK OF THERE IS SOME ISENTROPIC LIFT ALONG THE FRONT COINCIDENT WITH DIVERGENCE ALOFT. IT NOW APPEARS THE BEST PRECIP CHANCES WILL BE FRI NIGHT AS THE FRONT LIFTS BACK NORTH AND WEAK SURFACE WAVE TRAVELS EAST. LACK OF STRONG FORCING AND NOCTURNAL TIMING WILL LIKELY RESULT IN LIGHT PATCHES OF RAIN OVERNIGHT...LOW CHANCE SHOULD COVER MOST OF THE AREA WITH ONLY A COUPLE HUNDREDTHS OF QPF. FORECAST FOR SAT REMAINS UP IN THE AIR. 00Z GFS PUSHES THE SURFACE FRONT NORTH OF THE REGION AS WEAK 5H RIDGE BUILDS NORTH AND LOW PRESSURE MOVES THROUGH THE KY VALLEY. HOWEVER THE NAM/CANADIAN/AND 12Z ECMWF KEEP THE FRONT STALLED IN THE AREA WITH SHOWERS AND THUNDERSTORMS DEVELOPING IN THE AFTERNOON. GIVEN THE CONSENSUS BETWEEN THE 00Z NAM/CANADIAN...12Z ECMWF AND HPC WILL FAVOR THE WETTER COOLER SOLUTION FOR SAT. GOING TO INTRODUCE POP FOR SAT/SAT NIGHT...THOUGH ONLY SLIGHT CHANCE FOR NOW AND KNOCK BACK TEMPS A DEGREE OR TWO. HOWEVER...IF THE GFS SOLUTION IS THE CORRECT ONE TEMPERATURES COULD BE 5 DEGREES WARMER SAT AFTERNOON WITH NO THREAT OF PRECIP. FRONT EVENTUALLY PUSHES NORTH OF THE AREA LATE SAT OR SAT NIGHT WITH WEAK WARM ADVECTION KEEPING TEMPERATURES ABOVE CLIMO OVERNIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT WILL DROP SOUTH ACROSS THE AREA SUN...FOLLOWED BY STRONG CANADIAN HIGH RIDGING DOWN THE COAST. PASSAGE OF THE FRONT IS LOOKING LESS AND LESS LIKE A PRECIP EVENT. DEEP WEST TO NORTHWEST FLOW AHEAD OF THE FRONT HELPS DRY THE COLUMN...AIDED BY WEAK 5H RIDGE BUILDING OVER THE SOUTHEAST. NORTHEAST FLOW CONTINUES MON INTO TUE WITH SURFACE HIGH WEDGING DOWN THE EASTERN SEABOARD. SURFACE RIDGE AXIS STARTS TO SHIFT OFFSHORE LATE TUE BUT IS INITIALLY SLOW TO MOVE SOUTHEAST OF THE AREA. RETURN FLOW STARTS TO DEVELOP ON WED AS THE CENTER OF THE HIGH PUSHES FARTHER OFF THE EAST COAST. DO SEE A HINT OF A WEAK COASTAL TROUGH DEVELOP TUE NIGHT INTO WED BUT VERY DRY AIR IN PLACE MINIMIZES THE THREAT OF PRECIP. PERIOD REMAINS DRY WITH SURFACE AND UPPER RIDGING IN PLACE. TEMPERATURES SUN AHEAD OF THE FRONT SHOULD BE NEAR CLIMO...BUT THEN MON AND TUE END UP BELOW CLIMO IN COOL NORTHEAST FLOW. MON WILL LIKELY BE THE COOLEST DAY WITH SOME WARMING TUE AS THE AIR MASS MODIFIES. RETURN FLOW AT THE END OF THE PERIOD WILL RETURN TEMPS BACK TO CLIMO. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 18Z...MCS IS DYING WITH MOST OF THE MOISTURE REMAINING NORTH OF THE REGION. EXPECT SCATTERED CONVECTION TO REFIRE THIS AFTERNOON. COVERAGE AND TIMING ARE STILL AN ISSUE...BUT WITH THE STEEP MID LEVEL LAPSE RATES THERE WILL LIKELY BE SOME STRONG STORMS SOMEWHERE IN THE EASTERN CAROLINAS. WE THINK THE BEST CHANCE WILL BE ACROSS NC WHERE THE HIGHEST PRECIPITABLE WATER VALUES ARE. STRONG SOUTHWEST SURFACE WINDS WILL CONTINUE THROUGH THE AFTERNOON HOURS...GUSTS TO 30 KTS LIKELY. TONIGHT...A SECONDARY ROUND OF CONVECTION IS POSSIBLE WITH A SECOND UPPER DISTURBANCE. SURFACE WINDS WILL DIMINISH BUT WILL REMAIN ABOVE 8 KTS MOST OF THE NIGHT. FRIDAY...EXPECT VFR WITH MORE OF A NORTHWESTERLY FLOW AS A POORLY DEFINED FRONT SAGS SOUTH. LOOK FOR CONVECTION TO REFIRE FRIDAY AFTERNOON. EXTENDED OUTLOOK...SCATTERED SHOWERS AND STORMS POSSIBLE FRIDAY AFTERNOON THROUGH THE EVENING HOURS. ISOLATED STORMS SATURDAY. VFR SUNDAY AND MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM THURSDAY...PREVIOUS FORECAST REMAINS ON TRACK. LATEST OBSERVATIONS FROM BUOYS AND COASTAL SITES SHOW GUSTS IN THE 25-30 KT RANGE. WINDS SHOULD INCREASE ANOTHER 2-3 KNOTS THROUGH THE AFTERNOON HOURS. SEAS ARE 8 FT OUT AT THE FRYING PAN SHOALS BUOY...AND AS HIGH AS 6 FT AT THE OCEAN CREST PIER WAVE GAUGE. PREVIOUS DISCUSSION FROM 1030 AM FOLLOWS... A TIGHT PRESSURE GRADIENT ALONG THE SOUTH SIDE OF LOW PRESSURE IN VIRGINIA WILL MAINTAIN WINDY CONDITIONS ACROSS THE COASTAL WATERS TODAY. SUSTAINED WINDS HAVE ALREADY REACHED 25 KT WITH GUSTS NEAR 30 KT AT THE FRYING PAN SHOALS WEATHER BUOY. SUSTAINED WINDS COULD APPROACH 30 KT LATER THIS AFTERNOON AS THE CORE OF THE STRONGEST WINDS MOVES ACROSS THE AREA. WIND SPEEDS SHOULD REMAIN JUST BELOW GALE (34 KT) CRITERIA...BUT THIS SHOULD CERTAINLY BE THOUGHT OF AS A "HIGH END" SMALL CRAFT ADVISORY. RADAR COMPOSITES SHOW A SQUALL LINE ACROSS THE WESTERN CAROLINAS THAT SHOULD DIE OUT BEFORE MAKING IT OFFSHORE THIS AFTERNOON. MODELS DO SHOW HOWEVER A SECOND UPPER DISTURBANCE DIVING SOUTHEAST INTO THE REGION TONIGHT THAT MAY IGNITE SOME SHOWERS AND STORMS...ESPECIALLY ACROSS THE NC WATERS. SEAS HAVE BUILT AS HIGH AS 8 FEET OUT AT THE FRYING PAN SHOALS BUOY...3-4 FT AT OUR NEARSHORE CORMP BUOYS. SEAS SHOULD BUILD ANOTHER 1-2 FT BY LATE THIS AFTERNOON. WITH THE STRONG SOUTHWEST WINDS CONTINUING. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 AM THURSDAY...SOUTHWEST FLOW OVER THE WATERS AT THE START OF THE PERIOD WILL DECREASE AND BECOME HIGHLY VARIABLE AS COLD FRONT DROPS IN FROM THE NORTH. APPEARS FRONT WILL STALL ACROSS THE WATERS...NEAR CAPE FEAR. THE RESULT BEING LIGHT WINDS WITH A NORTHERLY COMPONENT ON THE NORTH SIDE OF THE FRONT AND WHILE LIGHT SOUTHERLY WINDS ARE FOUND SOUTH OF THE BOUNDARY. STALLED BOUNDARY LIFTS NORTH AS A WARM FRONT FRI NIGHT WITH SOUTHERLY FLOW DEVELOPING ACROSS ALL WATERS EARLY SAT. GRADIENT BECOMES PINCHED LATE SAT AND SAT NIGHT WITH SPEEDS INCREASING TO 15 TO 20 KT BY THE END OF THE PERIOD. SEAS 3 TO 5 FT FRI MORNING SUBSIDING TO 2 TO 4 FT LATE FRI INTO SAT BEFORE INCREASE IN WINDS SAT NIGHT RETURNS SEAS TO 3 TO 5 FT. MAIN WAVE COMPONENT WILL BE SOUTHERLY SWELL FROM PROLONGED SOUTH TO SOUTHWEST WINDS. LIGHT NORTHEAST FLOW DEVELOPING FRI MAY ADD A LITTLE CHOP TO NC WATERS. LONG TERM /SUNDAY THROUGH MONDAY/... AS OF 3 AM THURSDAY...COLD FRONT WILL DROP SOUTH ACROSS THE WATERS FROM THE NORTH ON SUN WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT. BRIEF PERIOD OF SOUTHERLY FLOW SUN MORNING WILL BE REPLACED BY NORTH TO NORTHEAST FLOW BY MIDDAY. INITIALLY GRADIENT WILL BE ON THE WEAK SIDE WITH NORTH TO NORTHEAST FLOW AROUND 10 KT. COLD SURGE SUN NIGHT AS THE HIGH PUSHES SOUTH HELPS TIGHTEN THE GRADIENT WITH SPEEDS INCREASE TO 15 TO 20 KT AFTER MIDNIGHT. NORTHEAST FLOW REMAINS 15 TO 20 KT INTO MON AFTERNOON BEFORE GRADIENT STARTS TO RELAX AND SPEEDS DROP CLOSER TO 15 KT. SEAS START OUT 3 TO 4 FT BUT ONCE NORTHEAST FLOW PICKS UP SUN NIGHT SEAS START TO BUILD. HEADLINES MAY BE REQUIRED SUN NIGHT AND MON. DEVELOPING NORTHEAST WIND WAVE ON TOP OF SOUTHERLY SWELL WILL CREATE CHAOTIC SEAS ON MON. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252. && $$ NEAR TERM...TRA SHORT TERM...III LONG TERM...III AVIATION...43/TRA
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
210 PM EDT THU APR 26 2012 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA FROM THE NORTH RESULTING IN UNSETTLED WEATHER. THIS COLD FRONT IS EXPECTED TO BECOME STATIONARY FROM WEST TO EAST ACROSS OUR AREA FRIDAY AND SATURDAY. THE FRONT WILL MOVE OFF TO THE SOUTH ON SUNDAY AS A CANADIAN HIGH BUILDS OVER THE REGION. THEN THE HIGH WILL LINGER THROUGH THE EARLY PART OF NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY/... AS OF 145 PM...ELEVATED CONVECTION ALREADY FIRING ALONG A LINGERING BOUNDARY. ONE CLUSTER ENTERING THE CENTRAL NC MTNS...AND ANOTHER ENTERING THE SOUTHERN CHARLOTTE METRO AREA. THERE IS ENUF INSTBY FOR STORMS TO PRODUCE LARGE HAIL...BUT WIND THREAT PROBABLY SUBDUED DUE TO THE COOL BL. MEANWHILE...ATMOS CONTINUES TO DESTABILIZE ACRS KY/TN AHEAD OF AN APPROACHING COLD FRONT. GUIDANCE IS MIXED ON HOW QUICKLY WE CAN DEVELOP SBCAPE AND FURTHER DEVELOPMENT AWAY FROM THE BNDRY THIS AFTN. I HAVE POPS GRADUALLY RAMPING UP FROM WEST TO EAST...PEAKING EARLY EVENING THEN DIMINISHING OVERNIGHT. THE SPC MESOANALYSIS PAGE SHOWS EFFECTIVE SHEAR OF 40-50 KTS WITH MUCAPES 2000-3000+ J/KG ACRS KY/TN. AND THE RUC PROGS THIS ENVIRONMENT TO PROPAGATE INTO THE AREA. THE BIG QUESTION IS HOW THE BL WILL EVOLVE. THE LATEST FCST SNDGS SHOW SLOW EROSION OF COLD POOL AND 100+ J/KG OF SBCIN. THE NEW DAY 1 CONVECTIVE OUTLOOK HAS THE MTNS AND UPPER SAVANNAH VALLEY IN A SLIGHT...BUT NOT TO THE EAST. HIGH RES MODELS DO NOT SHOW AS MUCH ORGANIZATION WITH THIS AFTN/EVENINGS CONVECTION. SO HAIL MAY REMAIN THE MAIN THREAT...WITH SOME WIND THREAT IN THE MTNS. TEMPS WILL BE ABOVE NORMAL OVERNIGHT UNDER THE DEBRIS CLOUDINESS. FRIDAY...MODELS CONTINUE THEIR TREND OF A MORE SOUTHERN PUSH OF THE COLD FRONT. THEY ALSO AGREE ON DECENT INSTBY ALONG/SOUTH OF THE BNDRY AS IT STARTS TO LIFT NORTH AS A WARM FRONT DURING THE AFTN. TOOK A MODEL BLEND FOR POPS. THIS HIGHLIGHTS THE NE GA AND UPSTATE ZONES. SPC DAY 2 OUTLOOK HAS A SEE TEXT 5% FOR THOSE AREAS. SHEAR WILL BE WEAKER...BUT ANOTHER SHORTWAVE WILL RIPPLE THRU QUASI-ZONAL FLOW DURING PEAK HEATING...WITH FCST SNDGS SHOWING LESS CIN THAN TODAY. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AS OF 205 PM THURSDAY...A WEAK UPPER RIDGING WILL BUILD INTO THE SOUTHEAST U.S. FRI NIGHT-SAT...THEN WEAKENS SLIGHTLY SAT NIGHT BEFORE CONTINUING TO BUILD OVER THE AREA SUN. THE SFC BOUNDARY WILL PUSH N AS A WARM FRONT FRI NIGHT-EARLY SAT WITH BEST FORCING N OF THE CWA. WE KEPT SLIGHT CHC POPS OVER MAINLY THE MTNS AND N ZONES THRU SAT. AS A SFC RIDGE BUILDS INTO THE AREA FROM THE NE WITH SE SFC FLOW SETTING UP. UPSLOPE FORCING SHOULD BE ENOUGH TO MAINTAIN SLIGHT CHC POPS THRU THE DAY SUN...MAINLY OVER THE MTNS. EXPECT TEMPS ABOVE AVG SAT AND SUN WITH COLDER AIR PUSHING IN FROM THE NE DURING THE DAY SUN TO KEEP TEMPS BELOW AVG IN THE FAR NE CWA IN THE AFTN. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... AS OF 205 PM THURSDAY...HEIGHTS RISE SUN NIGHT-MON AS UPPER TROF MOVES OFF THE NE COAST AND UPPER RIDGE BUILDS INTO THE SE US. COLD AIR DAMMING CONTINUES TO DEVELOP SUN NIGHT AND SETTLES OVER THE AREA MON. STILL EXPECT ENOUGH LOW LVL MOISTURE AND FORCING FOR SLIGHT CHC POPS ACROSS THE AREA. WEDGE WEAKENS TUE AND SFC BOUNDARY MOVES N OF THE AREA AND STAYS N THRU THE PERIOD. THIS PUTS CWA BACK IN THE WARM SECTOR SO WITH MOIST S FLOW DEVELOPING WE HELD ON TO MENTION OF SLIGHT CHC OF MAINLY AFTN SHWRS AND TSTMS TUE-WED DEVELOPING MOIST SLY FLOW AND DIURNAL INSTABILITY. TEMPS WILL BE BELOW AVG MON...THEN BACK ABOVE AVG TUE-THU. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AT KCLT...MAIN CONCERN NEXT COUPLE OF HOURS WILL BE A SMALL LINE OF CONVECTION TRACKING SOUTH OF THE TERMINAL. NOT EXPECTING A DIRECT IMPACT ATTM...BUT THE SUBTLE BNDRY THIS ACTIVITY IS FIRING ALONG IS SLOWLY DRIFTING NWD. SO ADDITIONAL DEVELOPMENT TO THE WEST MAY AFFECT KCLT. OTHERWISE...EXPECT VFR WITH GUSTY SW WINDS THIS AFTN AFTN. THERE MAY BE ANOTHER ROUND OF CONVECTION THIS EVENING...AS A COLD FRONT WILL PUSH THRU THE AREA OVERNIGHT. CONFIDENCE IS TOO LOW THIS TIME...BUT MOST LIKELY TIME OF IMPACT SHUD BE IN THE 00Z TO 06Z TIME FRAME. WINDS WIL SHIFT NW BEHIND THE FRONT...THEN NE FRIDAY MORNING AND REMAIN LIGHT. DEBRIS CLOUDINESS ASSOCIATED WITH THE CONVECTION SHUD BE VFR. ELSEWHERE...A CLUSTER OF STORMS ARE MOVING INTO THE CENTRAL NC MTNS ATTM...AND WILL BE VCTS AT KAVL FOR NEXT COUPLE OF HOURS. CONVECTION MAY START TO DEVELOP LATER THIS AFTN ACRS THE REMAINDER OF THE AREA...SO VCTS WILL BE CARRIED. ANOTHER ROUND OF CONVECTION IS EXPECTED TO AFFECT THE REGION LATE THIS AFTN THRU THE EVENING...AS A COLD FRONT PUSHES THRU FROM THE NORTHWEST. CONVECTION SHUD WANE AFTER 06Z AND WINDS WILL SHIFT TO N/NW BEHIND THE FRONT. DEBRIS CLOUDINESS SHUD BE VFR. OUTLOOK...A COLD FRONT WILL LINGER INVOF THE FORECAST AREA THRU FRIDAY NIGHT. MAINLY PM SHOWERS/THUNDERSTORMS AND MORE WIDESPREAD RESTRICTIONS WILL BE POSSIBLE FRI AFTN AND OVERNIGHT. THE FRONT LIFTS NORTH SATURDAY...BUT THEN DROPS BACK IN SUNDAY. SO PERIODS OF RESTRICTIONS IN CLOUDS/PRECIP EXPECTED THRU THE WEEKEND. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...ARK SHORT TERM...RB LONG TERM...RB AVIATION...ARK
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
346 PM CDT THU APR 26 2012 .UPDATE... HAVE UPDATED THE FORECAST AND PRODUCTS TO INCLUDE THE SEVERE THUNDERSTORM WATCH THAT IS IN EFFECT FOR THE SOUTHWEST AND SOUTH- CENTRAL TEXAS PANHANDLE AND NORTHERN SOUTH PLAINS UNTIL 10 PM. NO OTHER CHANGES MADE ATTM. && .PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 26 2012/ SHORT TERM... MOIST EASTERLY FLOW THIS AFTERNOON WILL TURN 180 DEGREES BY TOMORROW MORNING AND DRY OUT BEHIND A DRYLINE AND WEAK PACIFIC COLD FRONT. UNTIL THEN...THE FORECAST CHALLENGE REMAINS FOCUSED ON TSTRM OPPORTUNITIES LATE THIS AFTN AND EVENING WITHIN A FAVORABLY MOIST AND DESTABILIZING ATMOSPHERE. AS OF 20Z...THIS WINDOW DOES APPEAR TO BE OPENING FURTHER AS THE LEADING EDGE OF HEIGHT FALLS IS NOW ADVANCING INTO ERN NM WELL IN ADVANCE OF A TIGHTLY-WOUND UPPER LOW IN CENTRAL AZ. VISIBLE SATELLITE CONFIRMS THIS TREND AS BOUNDARY LAYER CUMULUS AND MID-LEVEL CLOUDS HAVE QUICKLY THICKENED BETWEEN CLINES CORNERS AND CLOVIS. SURFACE OBSERVATIONS CLEARLY REVEAL THE DRYLINE WILL NOT MIX AS FAR EAST AS 12Z MODELS AND RECENT RUNS OF THE HRRR SUGGESTED...LARGELY DUE TO A SLOWER UPPER TROUGH AND ITS SUBSEQUENT DELAY WITH WESTERLY SURFACE FLOW. SURFACE FRONT FROM EARLIER THIS MORNING HAS ESSENTIALLY DIFFUSED...ALTHOUGH MODELS INDICATE SOME SEMBLANCE OF THIS A FEW THOUSAND FEET ALOFT LIFTING SLOWLY NORTH AS A WARM FRONT. LATEST RUC APPEARS THE MOST CREDIBLE WITH THE DRYLINE SHARPENING UP NEAR HWY 385 BEFORE SUNSET INSTEAD OF I27 AS PREVIOUSLY THOUGHT. EXODUS OF A SUBTROPICAL CIRRUS SHIELD ACROSS THE NWRN HALF OF THE CWA HAS ALREADY PUSHED CIN TO NEAR ZERO IN PLACES...WITH HIGH-BASED CUMULONIMBUS FOUND DEVELOPING FROM NEAR TCC NORTHEAST TO NEAR CHANNING...AND ALSO SOUTHWARD INTO OUR WRN COUNTIES. CAPE INCREASES MARKEDLY FARTHER EAST WHERE MOISTURE IS SIGNIFICANTLY BETTER...SO TEND TO BELIEVE A LARGE HAIL THREAT WILL DOMINATE AS STORMS FAVOR DISCRETE MODES...LIKELY SUPERCELLULAR GIVEN FAVORABLE BOUNDARY-ORIENTED 0-6KM SHEAR VECTORS. RECENT SWOMCD FULLY CONFIRMS THREAT FOR SVR CONVECTION. AS EARLIER AFD MENTIONED...THE GREATEST COVERAGE OF CONVECTION SHOULD TAKE AIM NORTH OF THE CWA GENERALLY ALONG AND NORTH OF THE AXIS OF A CYCLONICALLY-CURVED UPPER JET STREAK. WILL HOWEVER MAINTAIN ISO TSTRM MENTION MAINLY OVER OUR NRN COUNTIES THROUGH MIDNIGHT AS THIS REGION WILL LIE NEAR THE EDGE OF DEEP ASCENT. DRYLINE SHOULD BE OVERTAKEN BY A PACIFIC COLD FRONT BEFORE SUNRISE FRI AT WHICH POINT BREEZY WESTERLY WINDS WILL DEVELOP...WITH DEEPER MIXING BY MID-MORNING LIKELY SECURING SUSTAINED WLY WINDS OF 20-25 MPH. DEPARTURE OF THE UPPER TROUGH FROM SERN CO INTO NEBRASKA BY 18Z IMPLIES A DIMINISHED GRADIENT FLOW LOCALLY...SO DESPITE MORE UNSEASONABLE WARMTH...FIRE WEATHER CONCERNS DO NOT APPEAR ROBUST ENOUGH FOR A FIRE WEATHER WATCH AS WINDS WILL BE DIMINISHING THROUGHOUT THE DAY. LONG TERM... ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY...WITH A PERIOD OF UNSETTLED WEATHER POSSIBLE FROM THE LATTER HALF OF THE WEEKEND INTO AT LEAST EARLY NEXT WEEK. THE MID-LEVEL PATTERN THROUGH MUCH OF THE EXTENDED WILL BE DOMINATED BY SOME SEMBLANCE OF WESTERN TROUGHING...WHICH WILL KEEP WEST TEXAS UNDER VARIATIONS OF SOUTHWEST FLOW ALOFT. EARLY ON...A SHORTWAVE TROUGH WILL QUICKLY LIFT NORTHWARD ACROSS THE UPPER MIDWEST AS A CLOSED LOW MIGRATES FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS FROM FRIDAY INTO SATURDAY. THIS SHOULD HELP FORCE A COLD FRONT SOUTHWARD INTO THE SOUTH PLAINS ON SATURDAY BEFORE IT STALLS OUT LATER IN THE DAY. THE INITIAL FROPA STILL APPEARS TO BE A DRY ONE...WITH THE BETTER LOW-LEVEL MOISTURE SHUNTED SOUTH AND EAST OF THE AREA. HOWEVER...BY SATURDAY NIGHT...A SOUTHERLY LLJ WILL INCREASE AND BEGIN TO DRAW BETTER AMOUNTS OF MOISTURE UP AND OVER THE COOL DOME IN PLACE...AND THIS WAA REGIME WILL RESULT IMPROVING CHANCES OF ELEVATED SHOWERS/STORMS. LATEST INDICATIONS ARE THAT THE FRONT WILL GRADUALLY RETREAT NORTHWARD SATURDAY NIGHT AND EARLY SUNDAY...WITH PERHAPS A MCS DEVELOPING TO ITS NORTH. RIGHT NOW...IT APPEARS THE MOST FAVORED REGION FOR A POTENTIAL MCS WOULD BE DISPLACED TO THE NORTH...ACROSS THE PANHANDLES...THOUGH THIS COULD CHANGE DEPENDING ON THE EXACT POSITION OF THE FRONT. FOR NOW...HAVE CURTAILED POPS TO FAVOR THE NORTHERN AND NORTHEASTERN SECTIONS SATURDAY NIGHT AND EARLY SUNDAY...WITH MORE DEVELOPMENT POSSIBLE ALONG THE DRYLINE /LIKELY LOCATED NEAR THE TX/NM LINE/ BY LATER IN THE DAY SUNDAY. THE 12Z NAM DOES ATTEMPT TO FORCE THE FRONT BACK SOUTHWARD LATER SUNDAY...LIKELY AS A RESULT OF A REINFORCED COLD POOL FROM THE EARLY DAY MCS...BUT THESE DETAILS REMAIN TOO ELUSIVE/UNCERTAIN TO FOLLOW ATTM. TEMPERATURES DO ALSO REMAIN A LITTLE TRICKY THIS WEEKEND GIVEN SOME UNCERTAINTY WITH THE FRONTAL POSITION...BUT HAVE TENDED TOWARD A COMPROMISE FOR NOW...WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S. EARLY NEXT WEEK WILL FEATURE A DRYLINE ROAMING THE AREA UNDERNEATH SOUTHWEST FLOW ALOFT AND THIS PATTERN WILL KEEP AT LEAST LOW THUNDER CHANCES IN THE FORECAST...FAVORING THE AFTERNOON AND EVENING HOURS. TOWARD THE MIDDLE OF NEXT WEEK THE MID-LEVEL FLOW MAY TURN MORE WESTERLY /AND MAYBE EVEN WEAKLY ANTICYCLONIC/ AND THIS WOULD TEND TO PUSH THE BETTER MOISTURE EASTWARD AND MAKE LOW THUNDER CHANCES EVEN LESS CERTAIN. THUS...HAVE MAINTAINED A DRY FORECAST FROM WEDNESDAY ONWARD FOR NOW. TEMPERATURES FOR NEXT WEEK WILL AGAIN BE ON THE WARM SIDE OF AVERAGE...WITH HIGHS GENERALLY IN THE 80S. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 52 82 47 75 49 / 20 0 10 10 20 TULIA 55 85 49 75 52 / 20 0 10 10 30 PLAINVIEW 56 85 51 76 55 / 20 0 10 10 20 LEVELLAND 54 86 53 80 57 / 10 0 10 10 20 LUBBOCK 60 88 55 80 58 / 10 0 10 10 20 DENVER CITY 54 86 53 83 55 / 10 0 0 10 20 BROWNFIELD 55 88 54 82 60 / 10 0 10 10 20 CHILDRESS 63 93 56 80 59 / 20 10 10 10 30 SPUR 61 91 56 81 61 / 10 0 10 10 20 ASPERMONT 67 96 59 84 61 / 10 0 10 10 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 93/23
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
315 PM CDT THU APR 26 2012 .SHORT TERM... MOIST EASTERLY FLOW THIS AFTERNOON WILL TURN 180 DEGREES BY TOMORROW MORNING AND DRY OUT BEHIND A DRYLINE AND WEAK PACIFIC COLD FRONT. UNTIL THEN...THE FORECAST CHALLENGE REMAINS FOCUSED ON TSTRM OPPORTUNITIES LATE THIS AFTN AND EVENING WITHIN A FAVORABLY MOIST AND DESTABILIZING ATMOSPHERE. AS OF 20Z...THIS WINDOW DOES APPEAR TO BE OPENING FURTHER AS THE LEADING EDGE OF HEIGHT FALLS IS NOW ADVANCING INTO ERN NM WELL IN ADVANCE OF A TIGHTLY-WOUND UPPER LOW IN CENTRAL AZ. VISIBLE SATELLITE CONFIRMS THIS TREND AS BOUNDARY LAYER CUMULUS AND MID-LEVEL CLOUDS HAVE QUICKLY THICKENED BETWEEN CLINES CORNERS AND CLOVIS. SURFACE OBSERVATIONS CLEARLY REVEAL THE DRYLINE WILL NOT MIX AS FAR EAST AS 12Z MODELS AND RECENT RUNS OF THE HRRR SUGGESTED...LARGELY DUE TO A SLOWER UPPER TROUGH AND ITS SUBSEQUENT DELAY WITH WESTERLY SURFACE FLOW. SURFACE FRONT FROM EARLIER THIS MORNING HAS ESSENTIALLY DIFFUSED...ALTHOUGH MODELS INDICATE SOME SEMBLANCE OF THIS A FEW THOUSAND FEET ALOFT LIFTING SLOWLY NORTH AS A WARM FRONT. LATEST RUC APPEARS THE MOST CREDIBLE WITH THE DRYLINE SHARPENING UP NEAR HWY 385 BEFORE SUNSET INSTEAD OF I27 AS PREVIOUSLY THOUGHT. EXODUS OF A SUBTROPICAL CIRRUS SHIELD ACROSS THE NWRN HALF OF THE CWA HAS ALREADY PUSHED CIN TO NEAR ZERO IN PLACES...WITH HIGH-BASED CUMULONIMBUS FOUND DEVELOPING FROM NEAR TCC NORTHEAST TO NEAR CHANNING...AND ALSO SOUTHWARD INTO OUR WRN COUNTIES. CAPE INCREASES MARKEDLY FARTHER EAST WHERE MOISTURE IS SIGNIFICANTLY BETTER...SO TEND TO BELIEVE A LARGE HAIL THREAT WILL DOMINATE AS STORMS FAVOR DISCRETE MODES...LIKELY SUPERCELLULAR GIVEN FAVORABLE BOUNDARY-ORIENTED 0-6KM SHEAR VECTORS. RECENT SWOMCD FULLY CONFIRMS THREAT FOR SVR CONVECTION. AS EARLIER AFD MENTIONED...THE GREATEST COVERAGE OF CONVECTION SHOULD TAKE AIM NORTH OF THE CWA GENERALLY ALONG AND NORTH OF THE AXIS OF A CYCLONICALLY-CURVED UPPER JET STREAK. WILL HOWEVER MAINTAIN ISO TSTRM MENTION MAINLY OVER OUR NRN COUNTIES THROUGH MIDNIGHT AS THIS REGION WILL LIE NEAR THE EDGE OF DEEP ASCENT. DRYLINE SHOULD BE OVERTAKEN BY A PACIFIC COLD FRONT BEFORE SUNRISE FRI AT WHICH POINT BREEZY WESTERLY WINDS WILL DEVELOP...WITH DEEPER MIXING BY MID-MORNING LIKELY SECURING SUSTAINED WLY WINDS OF 20-25 MPH. DEPARTURE OF THE UPPER TROUGH FROM SERN CO INTO NEBRASKA BY 18Z IMPLIES A DIMINISHED GRADIENT FLOW LOCALLY...SO DESPITE MORE UNSEASONABLE WARMTH...FIRE WEATHER CONCERNS DO NOT APPEAR ROBUST ENOUGH FOR A FIRE WEATHER WATCH AS WINDS WILL BE DIMINISHING THROUGHOUT THE DAY. && .LONG TERM... ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY...WITH A PERIOD OF UNSETTLED WEATHER POSSIBLE FROM THE LATTER HALF OF THE WEEKEND INTO AT LEAST EARLY NEXT WEEK. THE MID-LEVEL PATTERN THROUGH MUCH OF THE EXTENDED WILL BE DOMINATED BY SOME SEMBLANCE OF WESTERN TROUGHING...WHICH WILL KEEP WEST TEXAS UNDER VARIATIONS OF SOUTHWEST FLOW ALOFT. EARLY ON...A SHORTWAVE TROUGH WILL QUICKLY LIFT NORTHWARD ACROSS THE UPPER MIDWEST AS A CLOSED LOW MIGRATES FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS FROM FRIDAY INTO SATURDAY. THIS SHOULD HELP FORCE A COLD FRONT SOUTHWARD INTO THE SOUTH PLAINS ON SATURDAY BEFORE IT STALLS OUT LATER IN THE DAY. THE INITIAL FROPA STILL APPEARS TO BE A DRY ONE...WITH THE BETTER LOW-LEVEL MOISTURE SHUNTED SOUTH AND EAST OF THE AREA. HOWEVER...BY SATURDAY NIGHT...A SOUTHERLY LLJ WILL INCREASE AND BEGIN TO DRAW BETTER AMOUNTS OF MOISTURE UP AND OVER THE COOL DOME IN PLACE...AND THIS WAA REGIME WILL RESULT IMPROVING CHANCES OF ELEVATED SHOWERS/STORMS. LATEST INDICATIONS ARE THAT THE FRONT WILL GRADUALLY RETREAT NORTHWARD SATURDAY NIGHT AND EARLY SUNDAY...WITH PERHAPS A MCS DEVELOPING TO ITS NORTH. RIGHT NOW...IT APPEARS THE MOST FAVORED REGION FOR A POTENTIAL MCS WOULD BE DISPLACED TO THE NORTH...ACROSS THE PANHANDLES...THOUGH THIS COULD CHANGE DEPENDING ON THE EXACT POSITION OF THE FRONT. FOR NOW...HAVE CURTAILED POPS TO FAVOR THE NORTHERN AND NORTHEASTERN SECTIONS SATURDAY NIGHT AND EARLY SUNDAY...WITH MORE DEVELOPMENT POSSIBLE ALONG THE DRYLINE /LIKELY LOCATED NEAR THE TX/NM LINE/ BY LATER IN THE DAY SUNDAY. THE 12Z NAM DOES ATTEMPT TO FORCE THE FRONT BACK SOUTHWARD LATER SUNDAY...LIKELY AS A RESULT OF A REINFORCED COLD POOL FROM THE EARLY DAY MCS...BUT THESE DETAILS REMAIN TOO ELUSIVE/UNCERTAIN TO FOLLOW ATTM. TEMPERATURES DO ALSO REMAIN A LITTLE TRICKY THIS WEEKEND GIVEN SOME UNCERTAINTY WITH THE FRONTAL POSITION...BUT HAVE TENDED TOWARD A COMPROMISE FOR NOW...WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S. EARLY NEXT WEEK WILL FEATURE A DRYLINE ROAMING THE AREA UNDERNEATH SOUTHWEST FLOW ALOFT AND THIS PATTERN WILL KEEP AT LEAST LOW THUNDER CHANCES IN THE FORECAST...FAVORING THE AFTERNOON AND EVENING HOURS. TOWARD THE MIDDLE OF NEXT WEEK THE MID-LEVEL FLOW MAY TURN MORE WESTERLY /AND MAYBE EVEN WEAKLY ANTICYCLONIC/ AND THIS WOULD TEND TO PUSH THE BETTER MOISTURE EASTWARD AND MAKE LOW THUNDER CHANCES EVEN LESS CERTAIN. THUS...HAVE MAINTAINED A DRY FORECAST FROM WEDNESDAY ONWARD FOR NOW. TEMPERATURES FOR NEXT WEEK WILL AGAIN BE ON THE WARM SIDE OF AVERAGE...WITH HIGHS GENERALLY IN THE 80S. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 52 82 47 75 49 / 20 0 10 10 20 TULIA 55 85 49 75 52 / 20 0 10 10 30 PLAINVIEW 56 85 51 76 55 / 20 0 10 10 20 LEVELLAND 54 86 53 80 57 / 10 0 10 10 20 LUBBOCK 60 88 55 80 58 / 10 0 10 10 20 DENVER CITY 54 86 53 83 55 / 10 0 0 10 20 BROWNFIELD 55 88 54 82 60 / 10 0 10 10 20 CHILDRESS 63 93 56 80 59 / 20 10 10 10 30 SPUR 61 91 56 81 61 / 10 0 10 10 20 ASPERMONT 67 96 59 84 61 / 10 0 10 10 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 93/23
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1236 PM CDT THU APR 26 2012 .AVIATION... FOR THE 18Z KAMA TAF...EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE TAF PERIOD. THOUGH THERE IS A SLIGHT CHANCE FOR TSRA BETWEEN 18 AND 06Z...THINK THIS IS VERY UNLIKELY GIVEN THAT THE LATEST RUN OF THE NAM AND HRRR MODELS SHOW THE CONVECTION STAYING WELL NW OF THE TERMINAL. THIS BIGGEST THREAT FOR TSRA WOULD BE JUST AHEAD OF THE PACIFIC COLD FRONT THAT SHOULD ARRIVE BETWEEN 03 AND 09Z...BUT EVEN THIS SEEMS UNLIKELY SO WILL NOT MENTION ANY TSRA IN THE TAF FOR NOW. WINDS WILL GENERALLY BE SOUTHEASTERLY UNTIL THE PACIFIC COLD FRONT MOVES THROUGH TONIGHT...SHIFTING WINDS TO WESTERLY. FOR THE 18Z KDHT AND KGUY TAFS...BIGGEST CONCERN WILL BE THE CHANCES FOR TSRA THROUGH 12Z. THE HIGHEST RISK OF TSRA FOR KDHT SHOULD BE BETWEEN 23 AND 03Z...THOUGH COULD SEE STORMS AS EARLY AS 21Z. AT KGUY...THE HIGHEST RISK WILL BETWEEN 00 AND 03Z...BUT COULD LINGER EVEN PAST 06Z. FOR NOW HAVE JUST MENTIONED TSRA WITH MVFR CONDITIONS...THOUGH TSRAGR...STRONG GUSTY WINDS LEADING TO CONVECTIVE LOW LEVEL WIND SHEAR...AND LOWER FLIGHT CATEGORIES WILL CERTAINLY BE POSSIBLE WITH SOME OF THESE STORMS. AS WITH KAMA...EXPECT A SUDDEN SHIFT TO WESTERLY WINDS WITH THE PACIFIC COLD FRONT THAT SHOULD MOVE THROUGH BETWEEN 03 AND 09Z. JOHNSON && .PREV DISCUSSION... /ISSUED 702 AM CDT THU APR 26 2012/ AVIATION... VFR CONDITIONS ARE TO PERSIST AT KAMA...KDHT...AND KGUY THROUGH AT LEAST 21Z. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE NORTHWESTERN PANHANDLE AND ADJACENT AREAS OF NEW MEXICO AND THE WESTERN OKLAHOMA PANHANDLE...BY 3 TO 5 PM. NEAR MVFR RESTRICTIONS MAY ACCOMPANY THIS CONVECTION AT OR AROUND THE KDHT AND KGUY SITES BETWEEN 26/22Z TO 27/04Z. TRENDS CONCERNING THESE STORMS WILL BE MONITORED. PREV DISCUSSION... /ISSUED 512 AM CDT THU APR 26 2012/ DISCUSSION... CURRENTLY AN UPPER LEVEL LOW MOVING ONSHORE ALONG THE BAJA COAST AND WILL BRING WITH IT THE NEXT CHANCE FOR PRECIPITATION FOR THE PANHANDLES. DRYLINE ASSOCIATED WITH THIS SYSTEM WILL SET UP NEAR THE TEXAS NEW MEXICO BORDER AND WILL PROVIDE A FOCUS FOR CONVECTION LATER TODAY. MODELS HAVE DRASTICALLY MOVED THE DRYLINE TO THE WEST IN THE PAST COUPLE OF RUNS AND THIS IS NOW CAUSING THE FOCUS FOR POTENTIALLY SEVERE WEATHER TO BE IN THE WESTERN AND CENTRAL TEXAS AND OKLAHOMA PANHANDLES. SPC HAS THE CENTRAL AND WESTERN PANHANDLES UNDER A SLIGHT RISK FOR SEVERE WEATHER. CAPE VALUES ACROSS MUCH OF THE PANHANDLES IS AOA 2000 J/KG AND 0-6KM BULK SHEAR NEAR 50 KTS. MAIN THREAT WITH STORMS THAT DO DEVELOP EAST OF THE DRYLINE WILL BE LARGE HAIL POSSIBLY 2 INCHES OR GREATER AS COLDER TEMPERATURES ALOFT WILL HELP SUPPORT LARGE HAIL GROWTH. IN ADDITION TO THE HAIL THREAT DAMAGING WINDS IS ALSO OF CONCERN ALONG WITH THE POSSIBILITY OF AN ISOLATED TORNADO AS STORMS COULD INTERACT WITH THE REMNANTS OF A BOUNDARY IN THE AREA. ANOTHER TOPIC OF CONCERN IS THE CAP OVER THE CENTRAL PARTS OF THE PANHANDLES...IF THE STORMS CAN STAY ORGANIZED AND STRONG ENOUGH THEY COULD POTENTIALLY BREAK THE CAP AND BE LONG LIVED AS THEY MOVE ACROSS THE PANHANDLES. AFTER THIS EVENING THINGS QUIET DOWN FOR A BIT AS THE UPPER LOW MOVES NORTHEAST OVER NORTHERN KANSAS AND WE GET INTO MORE OF A ZONAL PATTERN THROUGH THE EARLY PART OF THE WEEKEND. SUNDAY LOOKS TO BRING ANOTHER CHANCE OF PRECIPITATION AS SOUTHEASTERLY WINDS LOOK TO MOVE OVER A MOSTLY STATIONARY FRONT ALONG NORTH TEXAS. WINDS WILL BRING IN MOISTURE AND CAUSE ISENTROPIC LIFT ACROSS THE AREA THAT COULD LEAD TO SHOWERS AND THUNDERSTORMS ACROSS THE PANHANDLES. CLOUDY SKIES WILL BE AROUND ON SUNDAY AND THIS WILL HELP COOL THINGS DOWN AND GET THE AREA AWAY FROM RECORD BREAKING HEAT. STARTING TUESDAY OF NEXT WEEK ZONAL FLOW WILL PERSIST AND THERE LOOKS TO BE A SERIES OF WEAK WAVES IN THE MID AND UPPER LEVELS THAT COULD BRING SOME MORE CHANCES OF RAIN NEXT WEEK...HOWEVER CONFIDENCE IN THESE EVENTS BRINGING PRECIPITATION TO THE AREA IS LOW AT THIS TIME. MOULTON FIRE WEATHER... THE FIRE WEATHER WATCH THAT WAS IN EFFECT HAS BEEN CANCELLED DUE TO THE DRYLINE FORECASTED TO BE FURTHER WEST AND IT CAUSING HIGHER RELATIVE HUMIDITIES AND LOWER WINDS. IF THE FAR WEST AND ESPECIALLY SOUTHWEST TEXAS PANHANDLE DOES NOT RECEIVE PRECIPITATION THIS EVENING ELEVATED OR CRITICAL FIRE WEATHER WEATHER WILL BE POSSIBLE ON FRIDAY. THROUGH THE WEEKEND FIRE WEATHER WILL SUBSIDE AS RELATIVE HUMIDITIES SHOULD REMAIN ABOVE 20 PERCENT ALONG WITH RELATIVELY LIGHT WINDS. EA/MOULTON && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 16/15