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