Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/28/13

AREA FORECAST DISCUSSION

NWS MELBOURNE FL

 910 PM EDT SAT APR 27 2013

.DISCUSSION...

...MODERATE TO HIGH RIP CURRENT RISK SUNDAY...

TONIGHT...
PERSISTENT CLOUD LINE EXTENDING FROM NEAR CANAVERAL AND SEAWARD HAS
NECESSITATED ADDING A SMALL CHANCE FOR SHOWERS UNTIL AROUND
MIDNIGHT...MAINLY BREVARD AND COASTAL VOLUSIA.  THE 18Z GFS BACKED
OFF ON SLIGHT DRYING WORKING IN FROM THE EAST...SO THIS SMALL POP
MAY NEED TO BE EXTENDED INTO EARLY SUNDAY MORNING.

SUNDAY...PRECIPITABLE WATER IS FORECAST BELOW AN INCH IN THE
SOUTH...BUT VALUES OF 1.1 TO 1.2 INCHES ARE INDICATED IN THE NORTH.
THE 18Z MOS SHOWED 20 POPS THERE.  THERE COULD BE A FEW ATLANTIC
SHOWERS PUSHING ASHORE EARLY AND THINK THAT THE MAIN CHANCE FOR
AFTERNOON SHOWERS WILL BE ACROSS THE INTERIOR NORTH.  THE NEXT SHIFT
WILL HAVE TO LOOK AT WHETHER TO INCLUDE SMALL SHOWER CHANCES THERE.

&&

.AVIATION...
MAINLY VFR.  SLIGHT SHOWER CHANCES KDAB-KTIX-KMLB UNTIL ABOUT
04-06Z. SOME VFR CEILINGS MAY PERSIST THERE THROUGH LATE NIGHT AND
EVEN PUSH INLAND TO KSFB-KMCO-KISM SUNDAY MORNING.

&&

.MARINE...
TONIGHT/SUNDAY...
A WEAK INVERTED TROUGH HAS BEEN EMBEDDED IN THE ONSHORE FLOW ACROSS
THE NORTHERN WATERS.  THIS...ALONG WITH SOME RAIN STABILIZATION HAS
CAUSED WINDS THERE TO BE A LITTLE WEAKER THAN FORECAST.  THE GFS DID
NOT DIAGNOSE THIS WEAK FEATURE BUT THE RAP SHOWS IT DAMPENING OUT
OVERNIGHT.  A LONG FETCH OF EAST/SOUTHEAST FLOW THEN LOOKS TO BE A
SOLID 15 KNOTS...SUPPORTING A FRESH SWELL AT 10 SECONDS AND 4-5
FEET.  EXERCISE CAUTION IN THE OPEN ATLANTIC LOOKS PRUDENT INTO
SUNDAY.

41009 WAS STARTING TO SHOW A HINT OF A VERY LONG PERIOD SWELL.  THE
WAVE WATCH FORECASTS ABOUT A 16 SECOND PERIOD AT 3 FEET ON SUNDAY.
THIS WOULD LEAD TO A HIGH RIP CURRENT RISK.

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.

&&

$$

SHORT TERM...LASCODY
IMPACT WEATHER...SEDLOCK






AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 1011 PM EDT SAT APR 27 2013

.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT CONTINUE TO SLOWLY MARCH TOWARD THE
REGION FROM THE SOUTHERN PLAINS AND WILL MOVE THROUGH THE AREA
MONDAY NIGHT. THIS WILL RESULT IN INCREASING SHOWERS THROUGH
MONDAY NIGHT. THE PATTERN WILL REMAIN ACTIVE THROUGH THE WEEK WITH
CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
LATEST RAP MODEL INDICATING WEAK ISENTROPIC LIFT WITH MOISTURE
CONVERGENCE FOCUS ACROSS NORTHERN MIDLANDS/PIEDMONT. UPPER RIDGE
HOLDING ACROSS SOUTHERN MIDLANDS.  USED SREF POP GUIDANCE AND CUT
POPS BACK SIGNIFICANTLY ACROSS THE SOUTH FOR THE NEXT FEW HOURS
WHERE FORCING WEAK.

SHOWERS SHOULD INCREASE LATE AS ISENTROPIC ASCENT IMPROVES OVER
THE AREA. BY DAYBREAK SUNDAY EXPECT LIKELY SHOWERS ALONG AND NORTH
OF I-20 WITH HIGH CHANCE POPS SOUTH OF I-20. WITH EAST WINDS
PUSHING ADDITIONAL MOISTURE INTO THE AREA SHOWER INTENSITY WILL
BEGIN INCREASING BY DAYBREAK WITH MOST LOCATIONS SEEING UP TO ONE
QUARTER OF AN INCH. WITH THE EXTENSIVE CLOUDS TEMPERATURES
OVERNIGHT WILL GENERALLY BE IN THE MIDDLE 50S.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SUNDAY AND SUNDAY NIGHT...LOW PRESSURE WILL BE TRACKING FROM THE
CENTRAL MS VALLEY IN THE MORNING TO THE OHIO VALLEY MONDAY NIGHT.
THE COLD FRONT WILL CONTINUE MOVING INTO THE REGION AND WITH
SOUTHEAST WINDS THE CONFIDENCE IN SHOWERS ACROSS THE AREA IS HIGH.
HAVE INCREASED POPS FOR SUNDAY AND SUNDAY NIGHT AS WELL AS
RAINFALL AMOUNTS...WHILE LOWERING TEMPERATURES A COUPLE OF
DEGREES. RAINFALL AMOUNTS WILL BE GREATEST ACROSS THE WESTERN
MIDLANDS...DUE TO PROXIMITY TO THE FRONT...HOWEVER MOST LOCATIONS
WILL SEE BETWEEN ONE HALF AND ONE INCH OF RAINFALL THROUGH MONDAY
DAYBREAK. TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 70S FOR
DAYTIME HIGHS WITH OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

MONDAY AND MONDAY NIGHT...COLD FRONT WILL PUSH THROUGH THE
FORECAST AREA MONDAY AFTERNOON WITH SHOWERS TAPERING OFF BEHIND
THE FRONT MONDAY EVENING. ALTHOUGH THERE IS LIMITED INSTABILITY
WITH FORCING FROM THE FRONT THERE IS SOME POTENTIAL FOR THUNDER SO
HAVE REMAINED WITH SHOWERS AND ISOLATED THUNDERSTORMS. SKIES WILL
BEGIN TO SLOWLY CLEAR MONDAY NIGHT...HOWEVER WITH GENERAL
SOUTHERLY FLOW EXPECT PARTLY TO MOSTLY CLOUDY SKIES TO PERSIST
THROUGH MONDAY NIGHT. DAYTIME TEMPERATURES WILL BE IN THE LOWER TO
MIDDLE 70S WITH LOWS MONDAY NIGHT IN THE MIDDLE 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
DIFFERENCES IN TIMING APPEARING ON FRIDAY. THE PATTERN WILL REMAIN
ACTIVE THROUGH THE PERIOD WITH AN OMEGA BLOCK DEVELOPING DURING
THE LATTER HALF OF THE WEEK. THIS WILL RESULT IN SLOW PROGRESSION
OF THE SYSTEMS AND A DEEP UPPER LOW EXPECTED TO MOVE INTO THE
CENTRAL PLAINS BY NEXT FRIDAY. AT THE SURFACE WITH A LOW IN THE
MID MS VALLEY AND A HIGH OVER NEW ENGLAND A WEDGE PATTERN WILL
DEVELOP OVER THE FORECAST AREA. WITH CONSISTENCY IN THE MODELS
OVER THE PAST COUPLE OF RUNS HAVE TRENDED THE FORECAST TO THE
WEDGE WITH INCREASING CLOUDS AND LOWERED TEMPERATURES FOR THURSDAY
ONWARD. BLOCKING PATTERN WILL REMAIN IN TACT THROUGH THE END OF
THE LONG TERM KEEPING THE AREA UNDER THE INFLUENCE OF THE WEDGE.
TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL ON TUESDAY
THEN COOLER THAN NORMAL FOR WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
ISOLATED/WIDELY SCTD SHOWERS ACROSS PORTIONS OF THE SC UPSTATE AND
NORTHERN MIDLANDS. CHANCES OF RAIN WILL INCREASE MAINLY TOWARDS DAWN
AND INTO THE DAY SUNDAY AS HIGH PRESSURE SHIFTS FURTHER OFF THE NEW
ENGLAND COAST AND AN UPPER-LEVEL LOW MOVES INTO THE OH VALLEY.
MODELS NOW APPEAR MORE CONSISTENT IN SHOWING CEILINGS AND
VISIBILITIES DROPPING TO MVFR OVERNIGHT. MVFR RESTRICTIONS AND
RAINFALL EXPECTED TO CONTINUE THROUGH THE END OF THE TAF PERIOD ON
SUNDAY. WINDS ON SUNDAY WILL SHIFT TO SOUTHEAST AROUND 5 TO 8 KTS.

EXTENDED AVIATION OUTLOOK...RAINFALL AND CEILING/VSBY RESTRICTIONS
EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. RESTRICTIONS ALSO
POSSIBLE IN SHOWERS TUESDAY AND TUESDAY NIGHT.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$







AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 828 PM EDT SAT APR 27 2013

.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT CONTINUE TO SLOWLY MARCH TOWARD THE
REGION FROM THE SOUTHERN PLAINS AND WILL MOVE THROUGH THE AREA
MONDAY NIGHT. THIS WILL RESULT IN INCREASING SHOWERS THROUGH
MONDAY NIGHT. THE PATTERN WILL REMAIN ACTIVE THROUGH THE WEEK WITH
CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
LATEST RAP MODEL INDICATING WEAK ISENTROPIC LIFT WITH MOISTURE
CONVERGENCE FOCUS ACROSS NORTHERN MIDLANDS/PIEDMONT. UPPER RIDGE
HOLDING ACROSS SOUTHERN MIDLANDS.  USED SREF POP GUIDANCE AND CUT
POPS BACK SIGNIFICANTLY ACROSS THE SOUTH FOR THE NEXT FEW HOURS
WHERE FORCING WEAK.

SHOWERS SHOULD INCREASE LATE AS ISENTROPIC ASCENT IMPROVES OVER
THE AREA. BY DAYBREAK SUNDAY EXPECT LIKELY SHOWERS ALONG AND NORTH
OF I-20 WITH HIGH CHANCE POPS SOUTH OF I-20. WITH EAST WINDS
PUSHING ADDITIONAL MOISTURE INTO THE AREA SHOWER INTENSITY WILL
BEGIN INCREASING BY DAYBREAK WITH MOST LOCATIONS SEEING UP TO ONE
QUARTER OF AN INCH. WITH THE EXTENSIVE CLOUDS TEMPERATURES
OVERNIGHT WILL GENERALLY BE IN THE MIDDLE 50S.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SUNDAY AND SUNDAY NIGHT...LOW PRESSURE WILL BE TRACKING FROM THE
CENTRAL MS VALLEY IN THE MORNING TO THE OHIO VALLEY MONDAY NIGHT.
THE COLD FRONT WILL CONTINUE MOVING INTO THE REGION AND WITH
SOUTHEAST WINDS THE CONFIDENCE IN SHOWERS ACROSS THE AREA IS HIGH.
HAVE INCREASED POPS FOR SUNDAY AND SUNDAY NIGHT AS WELL AS
RAINFALL AMOUNTS...WHILE LOWERING TEMPERATURES A COUPLE OF
DEGREES. RAINFALL AMOUNTS WILL BE GREATEST ACROSS THE WESTERN
MIDLANDS...DUE TO PROXIMITY TO THE FRONT...HOWEVER MOST LOCATIONS
WILL SEE BETWEEN ONE HALF AND ONE INCH OF RAINFALL THROUGH MONDAY
DAYBREAK. TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 70S FOR
DAYTIME HIGHS WITH OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

MONDAY AND MONDAY NIGHT...COLD FRONT WILL PUSH THROUGH THE
FORECAST AREA MONDAY AFTERNOON WITH SHOWERS TAPERING OFF BEHIND
THE FRONT MONDAY EVENING. ALTHOUGH THERE IS LIMITED INSTABILITY
WITH FORCING FROM THE FRONT THERE IS SOME POTENTIAL FOR THUNDER SO
HAVE REMAINED WITH SHOWERS AND ISOLATED THUNDERSTORMS. SKIES WILL
BEGIN TO SLOWLY CLEAR MONDAY NIGHT...HOWEVER WITH GENERAL
SOUTHERLY FLOW EXPECT PARTLY TO MOSTLY CLOUDY SKIES TO PERSIST
THROUGH MONDAY NIGHT. DAYTIME TEMPERATURES WILL BE IN THE LOWER TO
MIDDLE 70S WITH LOWS MONDAY NIGHT IN THE MIDDLE 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
DIFFERENCES IN TIMING APPEARING ON FRIDAY. THE PATTERN WILL REMAIN
ACTIVE THROUGH THE PERIOD WITH AN OMEGA BLOCK DEVELOPING DURING
THE LATTER HALF OF THE WEEK. THIS WILL RESULT IN SLOW PROGRESSION
OF THE SYSTEMS AND A DEEP UPPER LOW EXPECTED TO MOVE INTO THE
CENTRAL PLAINS BY NEXT FRIDAY. AT THE SURFACE WITH A LOW IN THE
MID MS VALLEY AND A HIGH OVER NEW ENGLAND A WEDGE PATTERN WILL
DEVELOP OVER THE FORECAST AREA. WITH CONSISTENCY IN THE MODELS
OVER THE PAST COUPLE OF RUNS HAVE TRENDED THE FORECAST TO THE
WEDGE WITH INCREASING CLOUDS AND LOWERED TEMPERATURES FOR THURSDAY
ONWARD. BLOCKING PATTERN WILL REMAIN IN TACT THROUGH THE END OF
THE LONG TERM KEEPING THE AREA UNDER THE INFLUENCE OF THE WEDGE.
TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL ON TUESDAY
THEN COOLER THAN NORMAL FOR WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
AN AREA OF SHOWERS CURRENTLY EXTENDING FROM THE TN VALLEY TO THE SC
NORTHERN MIDLANDS. CHANCES OF RAIN WILL INCREASE TONIGHT AND
ESPECIALLY TOWARDS DAWN AND INTO THE DAY SUNDAY AS HIGH PRESSURE
SHIFTS FURTHER OFF THE NEW ENGLAND COAST AND AN UPPER-LEVEL LOW
MOVES INTO THE OH VALLEY. MODELS ARE CONSISTENT IN SHOWING CEILINGS
AND VISIBILITIES DROPPING TO MVFR OVERNIGHT. SOME MODELS ALSO
SHOWING IFR CEILINGS ON SUNDAY MORNING...BUT CONFIDENCE IS TOO LOW
TO INCLUDE AT THE MOMENT. MVFR RESTRICTIONS AND RAINFALL EXPECTED TO
CONTINUE THROUGH THE END OF THE TAF PERIOD ON SUNDAY. WINDS ON
SUNDAY WILL SHIFT TO SOUTHEAST AROUND 5 TO 8 KTS.

EXTENDED AVIATION OUTLOOK...RAINFALL AND CEILING/VSBY RESTRICTIONS
EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. RESTRICTIONS ALSO
POSSIBLE IN SHOWERS TUESDAY AND TUESDAY NIGHT.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$







AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 134 PM EDT FRI APR 26 2013

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW

&&

.SYNOPSIS...
ISSUED AT 319 AM EDT FRI APR 26 2013

AN UPPER TROUGH AND A SURFACE LOW WILL MOVE THROUGH THE AREA THIS
WEEKEND BRINGING SOME RAIN TO CENTRAL INDIANA. GENERALLY DRY
CONDITIONS WILL THEN PREVAIL UNTIL A COLD FRONT ARRIVES MID WEEK
NEXT WEEK AND BRINGS MORE CHANCES FOR RAIN.

TEMPERATURES WILL GRADUALLY WARM TO ABOVE AVERAGE BY NEXT WEEK...BUT
THEN FALL BEHIND THE COLD FRONT LATE IN THE WEEK.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT FRI APR 26 2013

A SUNNY START THIS MORNING ACROSS CENTRAL INDIANA ALTHOUGH HIGH
CLOUDS ARE ALREADY RAPIDLY EXPANDING INTO THE WABASH VALLEY FROM
THE WEST. WITH LIGHT SOUTHEAST FLOW AND WARM ADVECTION ONGOING...
TEMPS HAVE RISEN QUICKLY SINCE DAYBREAK WITH MOST AREAS AS OF 14Z
IN THE UPPER 40S AND LOWER 50S.

HIGH PRESSURE CENTERED OVER SOUTHERN OHIO THIS MORNING CONTINUING
TO INFLUENCE THE WEATHER ACROSS THE FORECAST AREA. THE HIGH WILL
DRIFT EAST SLOWLY THROUGH THE AFTERNOON AS A WARM FRONT APPROACHES
FROM THE SOUTHWEST. LARGE AREA OF PRECIP ASSOCIATED WITH THE WARM
FRONT CURRENTLY ACROSS THE SOUTHERN HALF OF MISSOURI WILL GRADUALLY
SHIFT NORTHEAST THROUGH THE REST OF THE DAY. WHILE CLOUDS WILL
STEADILY INCREASE INTO THE AFTERNOON...CONTINUED SOUTHEAST FLOW
WILL KEEP DRY CONDITIONS THROUGH THE BOUNDARY LAYER WITH RAINFALL
LIKELY TO DIMINISH AS IT ENCOUNTERS INCREASINGLY DRIER AIR OVER
THE REGION. RAP INDICATING INITIAL SURGE OF ISENTROPIC LIFT MAY
MAKE IT INTO THE LOWER WABASH VALLEY FOR THE SECOND HALF OF THE
AFTERNOON. WILL CONTINUE WITH LOW CHANCE POPS FOR LIGHT SHOWERS
THERE AND MAINTAIN DRY FORECAST ELSEWHERE. CONSIDERING THE QUICK
RISE THIS MORNING IN TEMPS...FORECAST HIGHS IN THE LOWER 60S LOOK
REASONABLE EVEN WITH THE INCREASING CLOUD COVER.

ZONE AND GRID UPDATES OUT.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 319 AM EDT FRI APR 26 2013

FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED FOR MOST ITEMS.

ALTHOUGH ISENTROPIC LIFT WILL INCREASE GRADUALLY TONIGHT...MOST OF
THE FORCING REMAINS SOUTH OF CENTRAL INDIANA. WILL GRADUALLY
INCREASE POPS DURING THE TONIGHT PERIOD...BUT BY THE END OF THE
PERIOD WILL ONLY HAVE LOW POPS ACROSS THE SOUTHWEST HALF OF THE
AREA.

ON SATURDAY AS THE UPPER TROUGH ENTERS THE AREA BY LATE IN THE
DAY...POPS WILL CONTINUE THEIR GRADUAL INCREASE AS FORCING GRADUALLY
INCREASES. BY THE END OF THE DAY THE SOUTHWEST THIRD OF THE AREA
SHOULD SEE ENOUGH FORCING TO HAVE LIKELY POPS WITH LOW POPS
NORTHEAST WHERE PRECIPITATION WILL BATTLE DRIER AIR.

AS THE UPPER TROUGH MOVES ACROSS THE AREA AND LIFT INCREASES
SATURDAY NIGHT...WENT LIKELY POPS MOST AREAS. WENT HIGHEST POPS
SOUTHEAST WHERE IMPACTS OF STRONGER 850MB WINDS WILL BE FELT.

ON SUNDAY AS SYSTEM SLOWLY MOVES EAST...CONTINUED LIKELY POPS EAST
WITH CHANCE POPS WEST...WITH SOME DECREASE IN THE POPS IN THE
AFTERNOON. ALTHOUGH THE LATEST MODEL RUNS HINT AT SOME LINGERING
PRECIPITATION SUNDAY NIGHT...FOR NOW HAVE KEPT THE FORECAST DRY
UNTIL THERE IS MORE AGREEMENT.

FOR TEMPERATURES THROUGH THE PERIOD...TRENDED TOWARD THE COOLER OF
THE MOS SATURDAY AND SUNDAY AND WARMER OF THE MOS SATURDAY NIGHT DUE
TO THE CLOUDS AND PRECIPITATION. OTHERWISE WENT WITH A BLEND.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 336 AM EDT FRI APR 26 2013

MAIN FOCUS ON THE EXTENDED WILL INVOLVE TIMING OF AN UPPER LOW THAT
WILL MOVE TO THE UPPER MIDWEST BY THURSDAY. THE 00Z DETERMINISTIC
GFS CONTINUES TO BE THE FASTEST MODEL MOVING THE UPPER LOW TO
NORTHEASTERN WISCONSIN BY THAT TIME...WHILE THE 00Z ECMWF HAS IT
FURTHER NORTHWEST AND NOT AS STRONG ACROSS WESTERN ONTARIO. THE 00Z
GEFS FAVORED THE WEAKER ECMWF REGARDING STRENGTH AND WAS IN BETWEEN
THE POSITIONING OF THE LOW ACROSS WESTERN LAKE SUPERIOR. SO...PREFER
ENSEMBLE GUIDANCE...BUT WITH CONFIDENCE LOW DUE TO THE LARGE MODEL
DIFFERENCES...PREFER TO STICK MOSTLY WITH THE INITIALIZATION
REGARDING POPS AND TEMPERATURES. THE INITIALIZATION DID SPIT OUT
SOME LOW POPS EARLY IN THE WEEK...BUT PREFERED TO REMAIN DRY THROUGH
TUESDAY NIGHT WITH ONLY WEAK FORCING. THEN...CHANCE POPS INCREASING
TOWARDS THURSDAY LOOK GOOD BASED ON THE ENSEMBLES AND WEAK FRONTAL
SYSTEM THAT IS EXPECTED TO MOVE THROUGH WEDNESDAY NIGHT OR THURSDAY
AHEAD OF THE UPPER SYSTEM. TEMPERATURES SHOULD ALSO CLIMB ABOVE
NORMAL IN THE 70S MONDAY THROUGH AT LEAST WEDNESDAY WITH LIGHT
SOUTHERLY FLOW AHEAD OF A WEAK FRONTAL SYSTEM. WITH TEMPERATURES IN
THE 70S AND SOUTHERLY FLOW WILL ALSO LEAVE THUNDER IN.

&&

.AVIATION /DISCUSSION FOR THE 26/18Z TAF ISSUANCE/...

ISSUED AT 129 PM EDT FRI APR 26 2013

VFR CONDITIONS EXPECTED FOR DURATION OF TAF PERIOD DESPITE
INCREASING MID AND HIGH CLOUDS THROUGH THIS EVENING. CONFIDENCE
WAS HIGH ENOUGH TO INSERT MENTION OF VCSH IN THIS TAF ISSUANCE FOR
TOMORROW MORNING AT KIND/KHUF/KBMG. WINDS WILL BE SOUTHERLY AT 5
TO 10 KTS.


&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD







AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 1011 AM EDT FRI APR 26 2013

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW

&&

.SYNOPSIS...
ISSUED AT 319 AM EDT FRI APR 26 2013

AN UPPER TROUGH AND A SURFACE LOW WILL MOVE THROUGH THE AREA THIS
WEEKEND BRINGING SOME RAIN TO CENTRAL INDIANA. GENERALLY DRY
CONDITIONS WILL THEN PREVAIL UNTIL A COLD FRONT ARRIVES MID WEEK
NEXT WEEK AND BRINGS MORE CHANCES FOR RAIN.

TEMPERATURES WILL GRADUALLY WARM TO ABOVE AVERAGE BY NEXT WEEK...BUT
THEN FALL BEHIND THE COLD FRONT LATE IN THE WEEK.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT FRI APR 26 2013

A SUNNY START THIS MORNING ACROSS CENTRAL INDIANA ALTHOUGH HIGH
CLOUDS ARE ALREADY RAPIDLY EXPANDING INTO THE WABASH VALLEY FROM
THE WEST. WITH LIGHT SOUTHEAST FLOW AND WARM ADVECTION ONGOING...
TEMPS HAVE RISEN QUICKLY SINCE DAYBREAK WITH MOST AREAS AS OF 14Z
IN THE UPPER 40S AND LOWER 50S.

HIGH PRESSURE CENTERED OVER SOUTHERN OHIO THIS MORNING CONTINUING
TO INFLUENCE THE WEATHER ACROSS THE FORECAST AREA. THE HIGH WILL
DRIFT EAST SLOWLY THROUGH THE AFTERNOON AS A WARM FRONT APPROACHES
FROM THE SOUTHWEST. LARGE AREA OF PRECIP ASSOCIATED WITH THE WARM
FRONT CURRENTLY ACROSS THE SOUTHERN HALF OF MISSOURI WILL GRADUALLY
SHIFT NORTHEAST THROUGH THE REST OF THE DAY. WHILE CLOUDS WILL
STEADILY INCREASE INTO THE AFTERNOON...CONTINUED SOUTHEAST FLOW
WILL KEEP DRY CONDITIONS THROUGH THE BOUNDARY LAYER WITH RAINFALL
LIKELY TO DIMINISH AS IT ENCOUNTERS INCREASINGLY DRIER AIR OVER
THE REGION. RAP INDICATING INITIAL SURGE OF ISENTROPIC LIFT MAY
MAKE IT INTO THE LOWER WABASH VALLEY FOR THE SECOND HALF OF THE
AFTERNOON. WILL CONTINUE WITH LOW CHANCE POPS FOR LIGHT SHOWERS
THERE AND MAINTAIN DRY FORECAST ELSEWHERE. CONSIDERING THE QUICK
RISE THIS MORNING IN TEMPS...FORECAST HIGHS IN THE LOWER 60S LOOK
REASONABLE EVEN WITH THE INCREASING CLOUD COVER.

ZONE AND GRID UPDATES OUT.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 319 AM EDT FRI APR 26 2013

FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED FOR MOST ITEMS.

ALTHOUGH ISENTROPIC LIFT WILL INCREASE GRADUALLY TONIGHT...MOST OF
THE FORCING REMAINS SOUTH OF CENTRAL INDIANA. WILL GRADUALLY
INCREASE POPS DURING THE TONIGHT PERIOD...BUT BY THE END OF THE
PERIOD WILL ONLY HAVE LOW POPS ACROSS THE SOUTHWEST HALF OF THE
AREA.

ON SATURDAY AS THE UPPER TROUGH ENTERS THE AREA BY LATE IN THE
DAY...POPS WILL CONTINUE THEIR GRADUAL INCREASE AS FORCING GRADUALLY
INCREASES. BY THE END OF THE DAY THE SOUTHWEST THIRD OF THE AREA
SHOULD SEE ENOUGH FORCING TO HAVE LIKELY POPS WITH LOW POPS
NORTHEAST WHERE PRECIPITATION WILL BATTLE DRIER AIR.

AS THE UPPER TROUGH MOVES ACROSS THE AREA AND LIFT INCREASES
SATURDAY NIGHT...WENT LIKELY POPS MOST AREAS. WENT HIGHEST POPS
SOUTHEAST WHERE IMPACTS OF STRONGER 850MB WINDS WILL BE FELT.

ON SUNDAY AS SYSTEM SLOWLY MOVES EAST...CONTINUED LIKELY POPS EAST
WITH CHANCE POPS WEST...WITH SOME DECREASE IN THE POPS IN THE
AFTERNOON. ALTHOUGH THE LATEST MODEL RUNS HINT AT SOME LINGERING
PRECIPITATION SUNDAY NIGHT...FOR NOW HAVE KEPT THE FORECAST DRY
UNTIL THERE IS MORE AGREEMENT.

FOR TEMPERATURES THROUGH THE PERIOD...TRENDED TOWARD THE COOLER OF
THE MOS SATURDAY AND SUNDAY AND WARMER OF THE MOS SATURDAY NIGHT DUE
TO THE CLOUDS AND PRECIPITATION. OTHERWISE WENT WITH A BLEND.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 336 AM EDT FRI APR 26 2013

MAIN FOCUS ON THE EXTENDED WILL INVOLVE TIMING OF AN UPPER LOW THAT
WILL MOVE TO THE UPPER MIDWEST BY THURSDAY. THE 00Z DETERMINISTIC
GFS CONTINUES TO BE THE FASTEST MODEL MOVING THE UPPER LOW TO
NORTHEASTERN WISCONSIN BY THAT TIME...WHILE THE 00Z ECMWF HAS IT
FURTHER NORTHWEST AND NOT AS STRONG ACROSS WESTERN ONTARIO. THE 00Z
GEFS FAVORED THE WEAKER ECMWF REGARDING STRENGTH AND WAS IN BETWEEN
THE POSITIONING OF THE LOW ACROSS WESTERN LAKE SUPERIOR. SO...PREFER
ENSEMBLE GUIDANCE...BUT WITH CONFIDENCE LOW DUE TO THE LARGE MODEL
DIFFERENCES...PREFER TO STICK MOSTLY WITH THE INITIALIZATION
REGARDING POPS AND TEMPERATURES. THE INITIALIZATION DID SPIT OUT
SOME LOW POPS EARLY IN THE WEEK...BUT PREFERED TO REMAIN DRY THROUGH
TUESDAY NIGHT WITH ONLY WEAK FORCING. THEN...CHANCE POPS INCREASING
TOWARDS THURSDAY LOOK GOOD BASED ON THE ENSEMBLES AND WEAK FRONTAL
SYSTEM THAT IS EXPECTED TO MOVE THROUGH WEDNESDAY NIGHT OR THURSDAY
AHEAD OF THE UPPER SYSTEM. TEMPERATURES SHOULD ALSO CLIMB ABOVE
NORMAL IN THE 70S MONDAY THROUGH AT LEAST WEDNESDAY WITH LIGHT
SOUTHERLY FLOW AHEAD OF A WEAK FRONTAL SYSTEM. WITH TEMPERATURES IN
THE 70S AND SOUTHERLY FLOW WILL ALSO LEAVE THUNDER IN.

&&

.AVIATION /DISCUSSION FOR THE 26/15Z TAF UPDATE/...

ISSUED AT 1009 AM EDT FRI APR 26 2013

UPDATE...
NO CHANGES.

PREVIOUS DISCUSSION...
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WOULD NOT RULE OUT
AN ISOLATED SHOWER OVERNIGHT AFTER 04Z AT HUF AND BMG...BUT COVERAGE
TOO LOW AND TOO FAR OUT FOR A MENTION IN THE TAFS. OTHERWISE...HIGH
AND MID CLOUDS WILL BE THICKENING TODAY WITH AN INCREASE IN DECK
AROUND 5K FEET FROM SOUTHWEST TO NORTHEAST TOWARD 12Z SATURDAY.

WINDS WILL INCREASE TO NEAR 10 KNOTS FROM THE SOUTH AFTER 13Z BEFORE
BECOMING SOUTHEAST LESS THAN 5 KNOTS AFTER 00Z.


&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD







AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 1003 AM EDT FRI APR 26 2013

.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 319 AM EDT FRI APR 26 2013

AN UPPER TROUGH AND A SURFACE LOW WILL MOVE THROUGH THE AREA THIS
WEEKEND BRINGING SOME RAIN TO CENTRAL INDIANA. GENERALLY DRY
CONDITIONS WILL THEN PREVAIL UNTIL A COLD FRONT ARRIVES MID WEEK
NEXT WEEK AND BRINGS MORE CHANCES FOR RAIN.

TEMPERATURES WILL GRADUALLY WARM TO ABOVE AVERAGE BY NEXT WEEK...BUT
THEN FALL BEHIND THE COLD FRONT LATE IN THE WEEK.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT FRI APR 26 2013

A SUNNY START THIS MORNING ACROSS CENTRAL INDIANA ALTHOUGH HIGH
CLOUDS ARE ALREADY RAPIDLY EXPANDING INTO THE WABASH VALLEY FROM
THE WEST. WITH LIGHT SOUTHEAST FLOW AND WARM ADVECTION ONGOING...
TEMPS HAVE RISEN QUICKLY SINCE DAYBREAK WITH MOST AREAS AS OF 14Z
IN THE UPPER 40S AND LOWER 50S.

HIGH PRESSURE CENTERED OVER SOUTHERN OHIO THIS MORNING CONTINUING
TO INFLUENCE THE WEATHER ACROSS THE FORECAST AREA. THE HIGH WILL
DRIFT EAST SLOWLY THROUGH THE AFTERNOON AS A WARM FRONT APPROACHES
FROM THE SOUTHWEST. LARGE AREA OF PRECIP ASSOCIATED WITH THE WARM
FRONT CURRENTLY ACROSS THE SOUTHERN HALF OF MISSOURI WILL GRADUALLY
SHIFT NORTHEAST THROUGH THE REST OF THE DAY. WHILE CLOUDS WILL
STEADILY INCREASE INTO THE AFTERNOON...CONTINUED SOUTHEAST FLOW
WILL KEEP DRY CONDITIONS THROUGH THE BOUNDARY LAYER WITH RAINFALL
LIKELY TO DIMINISH AS IT ENCOUNTERS INCREASINGLY DRIER AIR OVER
THE REGION. RAP INDICATING INITIAL SURGE OF ISENTROPIC LIFT MAY
MAKE IT INTO THE LOWER WABASH VALLEY FOR THE SECOND HALF OF THE
AFTERNOON. WILL CONTINUE WITH LOW CHANCE POPS FOR LIGHT SHOWERS
THERE AND MAINTAIN DRY FORECAST ELSEWHERE. CONSIDERING THE QUICK
RISE THIS MORNING IN TEMPS...FORECAST HIGHS IN THE LOWER 60S LOOK
REASONABLE EVEN WITH THE INCREASING CLOUD COVER.

ZONE AND GRID UPDATES OUT.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 319 AM EDT FRI APR 26 2013

FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND CAN BE USED FOR MOST ITEMS.

ALTHOUGH ISENTROPIC LIFT WILL INCREASE GRADUALLY TONIGHT...MOST OF
THE FORCING REMAINS SOUTH OF CENTRAL INDIANA. WILL GRADUALLY
INCREASE POPS DURING THE TONIGHT PERIOD...BUT BY THE END OF THE
PERIOD WILL ONLY HAVE LOW POPS ACROSS THE SOUTHWEST HALF OF THE
AREA.

ON SATURDAY AS THE UPPER TROUGH ENTERS THE AREA BY LATE IN THE
DAY...POPS WILL CONTINUE THEIR GRADUAL INCREASE AS FORCING GRADUALLY
INCREASES. BY THE END OF THE DAY THE SOUTHWEST THIRD OF THE AREA
SHOULD SEE ENOUGH FORCING TO HAVE LIKELY POPS WITH LOW POPS
NORTHEAST WHERE PRECIPITATION WILL BATTLE DRIER AIR.

AS THE UPPER TROUGH MOVES ACROSS THE AREA AND LIFT INCREASES
SATURDAY NIGHT...WENT LIKELY POPS MOST AREAS. WENT HIGHEST POPS
SOUTHEAST WHERE IMPACTS OF STRONGER 850MB WINDS WILL BE FELT.

ON SUNDAY AS SYSTEM SLOWLY MOVES EAST...CONTINUED LIKELY POPS EAST
WITH CHANCE POPS WEST...WITH SOME DECREASE IN THE POPS IN THE
AFTERNOON. ALTHOUGH THE LATEST MODEL RUNS HINT AT SOME LINGERING
PRECIPITATION SUNDAY NIGHT...FOR NOW HAVE KEPT THE FORECAST DRY
UNTIL THERE IS MORE AGREEMENT.

FOR TEMPERATURES THROUGH THE PERIOD...TRENDED TOWARD THE COOLER OF
THE MOS SATURDAY AND SUNDAY AND WARMER OF THE MOS SATURDAY NIGHT DUE
TO THE CLOUDS AND PRECIPITATION. OTHERWISE WENT WITH A BLEND.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 336 AM EDT FRI APR 26 2013

MAIN FOCUS ON THE EXTENDED WILL INVOLVE TIMING OF AN UPPER LOW THAT
WILL MOVE TO THE UPPER MIDWEST BY THURSDAY. THE 00Z DETERMINISTIC
GFS CONTINUES TO BE THE FASTEST MODEL MOVING THE UPPER LOW TO
NORTHEASTERN WISCONSIN BY THAT TIME...WHILE THE 00Z ECMWF HAS IT
FURTHER NORTHWEST AND NOT AS STRONG ACROSS WESTERN ONTARIO. THE 00Z
GEFS FAVORED THE WEAKER ECMWF REGARDING STRENGTH AND WAS IN BETWEEN
THE POSITIONING OF THE LOW ACROSS WESTERN LAKE SUPERIOR. SO...PREFER
ENSEMBLE GUIDANCE...BUT WITH CONFIDENCE LOW DUE TO THE LARGE MODEL
DIFFERENCES...PREFER TO STICK MOSTLY WITH THE INITIALIZATION
REGARDING POPS AND TEMPERATURES. THE INITIALIZATION DID SPIT OUT
SOME LOW POPS EARLY IN THE WEEK...BUT PREFERED TO REMAIN DRY THROUGH
TUESDAY NIGHT WITH ONLY WEAK FORCING. THEN...CHANCE POPS INCREASING
TOWARDS THURSDAY LOOK GOOD BASED ON THE ENSEMBLES AND WEAK FRONTAL
SYSTEM THAT IS EXPECTED TO MOVE THROUGH WEDNESDAY NIGHT OR THURSDAY
AHEAD OF THE UPPER SYSTEM. TEMPERATURES SHOULD ALSO CLIMB ABOVE
NORMAL IN THE 70S MONDAY THROUGH AT LEAST WEDNESDAY WITH LIGHT
SOUTHERLY FLOW AHEAD OF A WEAK FRONTAL SYSTEM. WITH TEMPERATURES IN
THE 70S AND SOUTHERLY FLOW WILL ALSO LEAVE THUNDER IN.

&&

.AVIATION /DISCUSSION FOR THE 26/12Z TAF ISSUANCE/...
ISSUED AT 530 AM EDT FRI APR 26 2013

VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WOULD NOT RULE OUT
AN ISOLATED SHOWER OVERNIGHT AFTER 04Z AT HUF AND BMG...BUT COVERAGE
TOO LOW AND TOO FAR OUT FOR A MENTION IN THE TAFS. OTHERWISE...HIGH
AND MID CLOUDS WILL BE THICKENING TODAY WITH AN INCREASE IN DECK
AROUND 5K FEET FROM SOUTHWEST TO NORTHEAST TOWARD 12Z SATURDAY.

WINDS WILL INCREASE TO NEAR 10 KNOTS FROM THE SOUTH AFTER 13Z BEFORE
BECOMING SOUTHEAST LESS THAN 5 KNOTS AFTER 00Z.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...MK








AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1051 PM MDT THU APR 25 2013

.UPDATE...
ISSUED AT 701 PM MDT THU APR 25 2013

HAVE ALLOWED THE RED FLAG WARNING TO EXPIRE DUE TO INCREASING RH
AND DECREASING WINDS.

INCREASED PRECIP. CHANCES OVERNIGHT FOR THE SOUTHEAST PARTS OF THE
AREA. MODELS AGREE THE BEST MOISTURE AND LIFT WILL BE OVER THOSE
LOCATIONS DURING THE OVERNIGHT HOURS. OTHERWISE CURRENT FORECAST
LOOKS TO BE IN VERY GOOD SHAPE.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 230 PM MDT THU APR 25 2013

EARLY AFTERNOON WV IMAGERY AND RUC ANALYSIS SHOW CLOSED LOW H5/H7
LOW OVER ARIZONA...WITH ENERGY AHEAD OF THIS FEATURE SPREADING NORTH
INTO WESTERN KS/EASTERN COLORADO. AT THE SURFACE A STRONG SURFACE
GRADIENT AS DEVELOPED IN RESPONSE TO SURFACE LOW DEEPENING OVER SOUTH
CENTRAL COLORADO.

WINDS GUSTS HAVE BEEN REPORTED THIS AFTERNOON IN THE 45-50 MPH
RANGE...AND RH VALUES HAVE DROPPED TO 15-17 PERCENT OVER EASTERN
PARTS OF THE CWA. CLOUD COVER COULD EVENTUALLY LIMIT
MIXING...HOWEVER WITH PEAK HEATING UNDERWAY I AM COMFORTABLE
KEEPING WIND ADVISORY AND RED FLAG WARNING IN PLACE WITH AFTERNOON
UPDATE.

CLOSED LOW OVER DESERT SW WILL EJECT OVER WESTERN KS TONIGHT INTO
EASTERN KS FRIDAY. WHILE H5 CENTER BECOMES MORE OF AN OPEN
WAVE...GUIDANCE IS INDICATING H7 CENTER REMAINING CLOSED AS IT
PASSES OVER KS. MODELS SHOW MID LEVEL FRONTOGENETICAL FORCING
OVERSPREADING OUR CWA THIS EVENING WITH POSSIBLE BAND FORMATION LATE
TONIGHT ON NW SIDE OF H7 LOW...POSSIBLY RESULTING IN BETTER RAIN
COVERAGE AND HIGHER RAIN TOTALS. THERE IS MINIMAL MU CAPE GENERALLY
LESS THAN 100 J/KG...HOWEVER GFS/NAM BOTH SHOW NEGATIVE THETA E
LAPSE RATES IN H8-H7 LAYER ASSOCIATED WITH MAIN AREA OF SHOWERS SO I
COULDNT RULE OUT A FEW WEAK THUNDERSTORMS WITH THIS ACTIVITY. HAVE
KEPT 50 POPS IN THE SOUTHEAST WHERE BETTER FORCING IS
ADVERTISED...WITH RAIN COMING TO AN END FOR MOSTLY LOCATIONS FRIDAY
MORNING. I KEPT SLIGHT CHANCE POPS LINGERING IN THE EASTERN PART OF
CWA TO ACCOUNT FOR POSSIBLE RAIN BAND LINGERING OVER NORTH CENTRAL
KS.

THERE WILL BE A WEAK COLD FRONT PASSING THROUGH THE CWA BY FRIDAY
MORNING...HOWEVER WITH CLEARING SKIES AND WAA IN THE AFTERNOON I
STILL EXPECT HIGHS FRIDAY TO REACH UPPER 60S/NEAR 70 IN THE WEST
(BASED ON MIXING THE LAST FEW DAYS). WARMING COULD BE LIMITED IN THE
EAST DUE TO CLOUDS/PRECIP POSSIBLY LINGERING.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 230 PM MDT THU APR 25 2013

FRIDAY NIGHT-SUNDAY...DRY WEATHER EXPECTED. WILL NEED TO WATCH
THE FAR EASTERN PORTIONS OF THE AREA FOR THUNDERSTORMS SATURDAY
AFTERNOON AS A SFC TROUGH MOVES THROUGH. THERE IS SOME WEAK
CONVERGENCE AND INSTABILITY ALONG THE WIND SHIFT WITH THIS
FEATURE...QUESTION RIGHT NOW IS HOW MUCH MOISTURE WILL BE
AVAILABLE. ANY THREAT FOR PRECIP SATURDAY AFTERNOON QUICKLY
DECREASES SATURDAY NIGHT AS THE SFC TROUGH MOVES EAST AND OUT OF
THE AREA. FOR SUNDAY GENERALLY SUNNY...MAY SEE SOME CIRRUS MOVE
DOWN FROM THE NORTH. LOWS FRIDAY NIGHT MID 30S TO LOW 40S WITH
UPPER 30S TO MID 40S SATURDAY NIGHT. HIGHS SATURDAY IN THE 70S
WITH MID 70S (WEST) TO MID 80S (EAST) SUNDAY.

SUNDAY NIGHT-MONDAY...COLD FRONT BRIEFLY PUSHES SOUTHWEST ACROSS
THE AREA SUNDAY NIGHT BEFORE RETREATING OUT OF THE AREA. NEAR OR
SLIGHTLY COOLER READINGS COMPARED TO SUNDAY EXPECTED ACROSS THE
NORTHEAST AND EAST WHERE PROXIMITY TO DEPARTING HIGH WILL BE FELT
MOST. TO THE WEST SIMILAR TO SLIGHTLY WARMER READINGS COMPARED TO
SUNDAY. LOWS MID 40S TO LOW 50S (WEST TO EAST) WITH HIGHS 75 TO 80
MONDAY.

MONDAY NIGHT-TUESDAY NIGHT...SFC TROUGH ACROSS THE AREA MONDAY NIGHT
WITH COLD FRONT MOVING THROUGH FROM THE NORTH TUESDAY. BREEZY NORTH
TO NORTHEAST WINDS TUESDAY NIGHT BEHIND THE FRONT. LOWS MONDAY NIGHT
MID 40S TO MID 50S (WEST TO EAST) WITH MID 30S TO MID 40S (WEST TO
EAST) TUESDAY NIGHT. HIGHS TUESDAY LOW 70S TO AROUND 80 (NORTH TO
SOUTH). SHOWERS AND A FEW THUNDERSTORMS POSSIBLE ACROSS THE EAST
TUESDAY AFTERNOON AHEAD OF THE FRONT. POST FRONTAL STABLE AIR MOVES
IN TUESDAY NIGHT. REMOVED MENTION OF THUNDERSTORMS BUT STILL HAVE A
CHANCE OF LIGHT RAIN.

WEDNESDAY-WEDNESDAY NIGHT...BREEZY NORTH WINDS TO CONTINUE ACROSS
THE EASTERN HALF OF THE AREA THROUGH THE DAY. SFC HIGH REMAINS OVER
THE AREA WEDNESDAY NIGHT ALLOWING FOR NEAR TO SLIGHTLY BELOW NORMAL
LOW TEMPERATURES. HIGHS IN THE MID TO UPPER 50S WITH LOWS MID TO
UPPER 30S. LOW CHANCES FOR SOME LIGHT RAIN OR RAIN SHOWERS DURING
THE DAY DECREASING DURING THE NIGHT.

THURSDAY...WARMER TEMPERATURES EXPECTED TO RETURN TO THE AREA AS
UPPER RIDGING SLOWLY MOVES IN FROM THE WEST. HIGHS MID 50S TO LOW
60S. CONTINUED LOW CHANCE FOR SOME LIGHT RAIN ACROSS THE AREA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1043 PM MDT THU APR 25 2013

VFR CONDITIONS ARE FORECAST FOR THE 6Z TAFS. SHOWER ACTIVITY FOR
THE NIGHT SHOULD REMAIN EAST OF KGLD AND WELL SOUTH OF KMCK.
WINDS HAVE TURNED TO THE SOUTHEAST AT KGLD DUE TO OUTFLOW FROM THE
SHOWERS. THE WINDS SHOULD TURN BACK TO THE SOUTH A COUPLE HOURS
AFTER 6Z IF NOT SOONER AS THE SHOWERS MOVE FURTHER AWAY.

OVERNIGHT WINDS WILL BECOME LIGHT AHEAD OF A WEAK COLD FRONT THAT
MOVES INTO THE AREA LATE TONIGHT/EARLY FRIDAY MORNING. THE NORTH
WINDS WILL BEGIN TO BECOME GUSTY BY LATE MORNING/EARLY AFTERNOON
THEN CALM IN THE EARLY EVENING.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

UPDATE...JTL
SHORT TERM...DR
LONG TERM...99
AVIATION...JTL







AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 415 AM CDT FRI APR 26 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI APR 26 2013

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER EASTERN MN AND
WEST CENTRAL WI EARLY THIS MORNING WILL PUSH EAST OF THE FA BY 15Z
AS A MID LEVEL SHORT WAVE PASSES BY. A WARM FRONT ACROSS THE MN
RIVER VALLEY WILL ALSO SLIDE NORTHEAST THIS MORNING WITH THE WARMEST
DAY SO FAR THIS YEAR OCCURRING. KEPT HIGHS ABOVE GUIDANCE WITH A
FAVORABLE LOW LEVEL THERMAL/WIND PATTERN. HIGHS ON THURSDAY TO OUR
WEST WERE ABOUT 20 DEGREES ABOVE THE H85 TEMPERATURE. THIS TREND
TODAY WOULD PUSH HIGHS INTO THE UPPER 60S FROM THE TWIN CITIES ON
SOUTHWEST WITH LOWER TO MIDDLE 60S ON NORTH AND EAST. ONLY THE FAR
NORTHWEST REACHES WILL LIKELY BE HELD IN THE UPPER 50S DUE THE SNOW
COVER.

THIS WILL BE THE FIRST 60 DEGREE READING FOR MSP THIS YEAR... COMING
JUST THREE DAYS SHORT OF TYING THE LATEST 60 DEGREE READING... SET
APRIL 29 1874. THE LATEST 60 DEGREE READING BEHIND 1874 IS APRIL 26
1904 AND AGAIN IN 1947. HIGHS IN THE 60S ARE ALSO FORECAST FOR KSTC
AND KEAU. THE LATEST 60 DEGREE READING FOR THE KSTC AREA IS APRIL 26
1947 AND 1965. FOR KEAU... THE LATEST 60 DEGREE READING IS APRIL 26
1951. HENCE...THESE WILL TIE FOR THE LATEST 60 DEGREE READING.

THERE WILL BE A TROUGH OF SURFACE LOW PRESSURE PROGRESS ACROSS THE
CWA DURING THE AFTERNOON AND EVENING HOURS. THERE IS A SMALL CHANCE
THAT A FEW SHOWERS COULD DEVELOP FROM LADYSMITH TO ALBERT LEA
TOWARDS EVENING. THE CONSENSUS BETWEEN THE VARIOUS WRF MODELS WAS
FOR SHOWERS TO BE EAST AND SOUTH OF THE CWA. ONLY THE MPXWRF AND
HOPWRF MEMBER 1 HAD A FEW SHOWERS LATE THIS AFTERNOON IN THE
AFOREMENTIONED AREA OF OUR CWA. THEREFORE... LEFT THE MENTION FOR
SHOWERS OUT. IT ALSO APPEARED THAT THE MODELS WERE FORECASTING DEW
POINT TOO HIGH THIS AFTERNOON. THEREFORE... STAYED ON THE
CONSERVATIVE SIDE WITH UPPER 30S TO LOWER 40S INSTEAD OF MIDDLE TO
UPPER 40S. THE LOWER DEW POINTS SEEM MORE REALISTIC WITH MIXING AND
A DRY ADIABATIC LAPSE RATE FORECAST TO 800 MB THIS AFTERNOON. THIS
RESULTS IN AFTERNOON MINIMUM HUMIDITY NEAR 35 PERCENT OUTSIDE OF
SNOW COVERED AREAS. FINALLY... ADDED AREAS OF FOG TO CENTRAL MN AND
WEST CENTRAL WI FOR LATE TONIGHT. WITH THE MELTING TODAY IN THESE
AREAS ALONG WITH HIGH PRESSURE AND LIGHT WINDS SETTLING IN
TONIGHT... BUFKIT NAM HYDROLAPSE RATES SHOW A NICE INCREASE DURING
THE LATE NIGHT HOURS.



.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI APR 26 2013

DRY AND WARM CONDITIONS WILL PREVAIL ON SATURDAY AS SOUTHERLY FLOW
INCREASES NOTICEABLY AHEAD OF FIRST WEAK COOL FRONT MARCHING
THROUGH MUCH OF MONTANA. FRONTAL BOUNDARY WILL TREK THROUGH MUCH
OF FA BY EARLY MONDAY MORNING...STALL FOR A SHORT PERIOD OF TIME
...AND THEN MIGRATE BACK NORTH INTO THE SOUTHERN MN AND WEST
CENTRAL WI PRIOR TO TUE/03Z. RIGHT REAR QUAD OF 75KT JET CORE
PUSHING INTO CENTRAL MN AND HEALTHY THETA E ADVECTION WILL BRING
ISOLATED STRONG THUNDERSTORMS FROM SOUTH CENTRAL MN TO WEST
CENTRAL WI ON SUNDAY EVENING...WITH BEST CHANCES AT THIS JUNCTURE
OVER SOUTH CENTRAL MN. 993MB SURFACE CYCLONE ON GFS40 HAS MEANDERED
FURTHER SOUTH OVER PAST 2 RUNS...BRINGING IT OVER NORTHERN AND
CENTRAL MN BY LATE TUESDAY MORNING...WITH STRONG COLD FRONT
STRETCHING SOUTH INTO SW MN AND NE SODAK. SECOND ROUND OF
STRONG THUNDERSTORMS WILL MATERIALIZE TUE/12Z-18Z...AS MUCH
MORE POTENT 110KT JET MAXIS BECOMES VISIBLE OVER NW MN AND
EASTERN NODAK. LUCKILY SIGNIFICANT INCREASE OF LOW LEVEL JET
DOES NOT OCCUR UNTIL LATE AFTN INTO THE EVEN...WHERE SOUTH
TO SW 850MB WINDS SHOULD BE IN THE 25 TO 35KT CATEGORY. PASSAGE
OF SECOND FRONTAL BOUNDARY THROUGH WESTERN WI WILL OCCUR BY
TUE NIGHT.

50H TROF WILL DIG OVER CWA ON WEDNESDAY AND THURSDAY AS MID
LEVEL CUT OFF LOW PRESSURE DEVELOPS OVER NORTHERN WI BY THU/18Z.
850MB TEMPS...WHICH WILL SPIKE INTO THE 10 TO 15 DEGREE VARIANCE
BY SUNDAY AFTN...WILL COLLAPSE BACK INTO THE NEGATIVE 8 TO 12C
RANGE BY THU MORNING. GFS40 HAS HANDLED TONIGHT`S CURRENT WEAK
CONVECTIVE SCENARIO WELL. EUROPEAN...WHICH HAD BEEN AN OUTLIER
CONCERNING THE DEVELOPMENT OF A MID LEVEL CUT OFF LOW THIS FAR
NORTH...IS NOW MORE IN TUNE WITH THE GFS. UNFORTUNATELY...BOTH
INDICATE THE PRESENCE OF THIS FEATURE OVER THE WESTERN GREAT
LAKES AND INTO MN THROUGH NEXT SATURDAY. THIS WILL KEEP US IN
FAIRLY ROBUST CAA AND WELL BELOW NORMAL TEMPS WED THROUGH AT
LEAST NEXT SATURDAY.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1135 PM CDT THU APR 25 2013

WARM FRONT SITTING FROM CENTRAL SODAK INTO CENTRAL IA THIS
EVENING. STRONG WARM ADVECTION NORTH OF THE BOUNDARY HAS
RESULTED IN RAPID EXPANSION OF MID LEVEL CLOUDS...WITH RADAR
RETURNS INCREASING. HOWEVER...WITH VERY DRY LOW LEVELS IN
PLACE...MOST OF THIS RAIN IS NOT REACHING THE GROUND WITH VFR
CONDS EXPECTED TO PREDOMINATE AS A RESULT. HRRR ALONG WITH THE
HOPWRF CONTINUE TO SHOW ENOUGH MOISTENING OCCURRING OVER WRN WI TO
ALLOW FOR SOME LIGHT RAIN TO REACH THE SFC. ONLY CHANGE FROM 00Z
TAFS WAS TO NARROW TEMPO SHRA WINDOW AT RNH/EAU. DURING THE DAY
FRIDAY...A WEAK SFC TROUGH WILL WORK INTO THE AREA...WHICH WILL
RESULT IN A DECREASE OF THE WINDS DURING THE DAY AS THEY VEER
AROUND TO THE W-NW.

KMSP...VFR CONDITIONS EXPECTED THROUGHOUT AS DRY LOW LEVELS KEEP
RAIN FROM REACHING THE SFC. MINIMAL COLD ADVECTION EXPECTED BEHIND
THE MORNING WIND SHIFT...WHICH WILL KEEP ANY LOW CLOUDS FROM
FORMING IN ITS WAKE. AS LLJ MOVES OVERHEAD TONIGHT...MAY HAVE SOME
WIND SHEAR...BUT WITH MINIMAL WIND SHIFT HAVE CONTINUED TO NOT
MENTION IT.

/OUTLOOK FOR KMSP/
SAT...VFR. SSW WINDS 10 KTS.
SUN...VFR. SSW WINDS 15-20 KTS.
MON...MVFR OR LOWER POSSIBLE WITH CHANE -SHRA/-TSRA. WIND SE 5-10 KTS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...RAH
LONG TERM...AJZ
AVIATION...MPG












AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 1136 PM CDT THU APR 25 2013

.UPDATE...

06Z AVIATION DISCUSSION ADDED BELOW.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 344 PM CDT THU APR 25 2013

WE WILL TURN THE CORNER IN TERMS OF TEMPERATURES OVER THE NEXT 24
HOURS AND REMAIN WARM THROUGH EARLY NEXT WEEK. A WARM FRONT
CURRENTLY IN THE DAKOTAS WILL MOVE ACROSS MN AND INTO WI LATE
TONIGHT. THIS FRONT WILL PRIMARILY COME THROUGH DRY IN MN...BUT
THERE IS A CHANCE FOR LIGHT RAIN IN WESTERN WI BETWEEN 1 AM AND 7
AM. THE ISENTROPIC LIFT ALREADY BEGINS TO INCREASE BETWEEN 03-06Z
IN WESTERN MN...BUT SATURATION IN THE LOWEST LEVELS OF THE
ATMOSPHERE ISN`T A SURE THING GIVEN DRIER IN PLACE BELOW 10000 FT.
THE FORECAST SOUNDINGS LATE TONIGHT LOOK MORE SUPPORTIVE OF A 2-4
HOUR WINDOW OF LIGHT RAIN IN WESTERN WI. THIS IS ALSO EVIDENT ON
THE ISENTROPIC SURFACES OF THE NAM AND TO SOME DEGREE GFS. THE
CONDENSATION PRESSURE DEFICITS ON THE 290K SURFACE DOESNT SUGGEST
SATURATION UNTIL YOU GET TO CENTRAL WI. THIS WOULD OVERLAP WITH
THE 850-700 MB...THAT IS FAIRLY DRY. THE 295K DOES SATURATE IN FAR
EASTERN MN AND WESTERN WI...WHICH IS CLOSER TO THE 700-600 MB
LAYER. AT ANY RATE...DESPITE OF THE OVERLAP IN QPF OFF THE
GFS/NAM/EC IT WAS HARD TO GO MUCH HIGHER IN THE POP FORECAST THAN
50-60%.

OTHERWISE...THE ONLY OTHER CHALLENGE IN THE SHORT TERM WAS TO
DETERMINE HOW WARM WE GET BEHIND THE WARM FRONT TOMORROW. THERE IS
STILL A FEW AREAS WITH SNOW ON THE GROUND...SO TRIED TO ADJUST TEMPS
DOWN A FEW DEGREES IN THESE AREAS. HOWEVER...GIVEN THE WARM AIR
ADVECTION AND LATE APRIL SUN IT`S HARD TO IMAGINE MUCH OF THE AREA
NOT GETTING WELL INTO THE 60S. 2M TEMPS OFF THE GFS AT 18Z EVEN MAKE
IT INTO THE LOWER 60S...AND IF THE KNOWN COOL GFS IS FORECASTING
THOSE TEMPS...THAN MID 60S ARE USUALLY A LOCK WITH SUNSHINE. IN
SOUTHERN MN...THE 925-850MB TEMPS JUMP 10-12 DEGREES C OVER THE NEXT
18 HOURS WITH THE WARM FRONT. THE GROUND IS STILL MOIST...SO 70S MAY
BE HARD TO COME BY TOMORROW BUT IT WILL NO DOUBT BE THE WARMEST DAY
OF THE YEAR SO FAR BY ABOUT 10-15 DEGREES.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 PM CDT THU APR 25 2013

THE HIGHLY ADVERTISED WARM-UP IS STILL ON TRACK TO CONTINUE INTO
THE WEEKEND. BY SATURDAY AFTERNOON...H85 TEMPS INCREASE TO BETWEEN
+7C AND +10C...WITH ADDITIONAL MODERATION INTO THE LOWER TEENS ON
SUNDAY PRIOR TO THE FRONTAL PASSAGE. EXPECT UPPER 60S TO LOWER 70S
TO BE COMMON SATURDAY AS A FEW AREAS WORK TO GET RID OF THE
REMAINING SNOWPACK. SUNDAY SHOULD BE THE WARMEST DAY OF THE
WEEKEND AS THE THERMAL RIDGE NOSES INTO THE AREA AHEAD OF THE
FRONT...AND DEEP MIXING YIELDS HIGHS IN THE LOW/MID 70S. COULD SEE
A FEW SHOWERS AND THUNDERSTORMS DEVELOP ALONG THE FRONT ON SUNDAY
AFTERNOON...ALTHOUGH HIGHER PROBABILITIES WILL ARRIVE ON SUNDAY
EVENING/NIGHT AS MORE MOISTURE ADVECTS INTO THE AREA. THE FRONT
STALLS JUST ALONG THE SOUTHEAST EDGE OF THE FORECAST AREA ON
MONDAY...WITH THE ATTENDANT WEAKLY UNSTABLE AIRMASS WARRANTING
INCLUSION OF 20-30 POPS FOR SHOWERS AND ISOLATED THUNDERSTORMS.

MUCH HIGHER PRECIP CHANCES ARRIVE ON TUESDAY AND WEDNESDAY...AS A
WARM FRONT LIFTS ACROSS THE AREA AND IS FOLLOWED BY THE PASSAGE OF
A STRONG COLD FRONT. DECENT MOISTURE/WARM AIR ADVECTION ARE
PROGGED BY THE MODELS...AS WELL AS STRONG 700-600MB FRONTOGENESIS
WITH THE MID LEVEL TROUGH. HAVE RETAINED HIGH CHANCE POPS
/ESPECIALLY FROM SOUTH CENTRAL MN INTO WEST CENTRAL WI/. WITH THE
TROUGH OVERHEAD...COOLER TEMPS WILL RESULT. HIGHS ON WEDNESDAY AND
THURSDAY WILL LIKELY TOP OUT IN THE 50S...WHILE LOWS RETURN TO THE
30S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1135 PM CDT THU APR 25 2013

WARM FRONT SITTING FROM CENTRAL SODAK INTO CENTRAL IA THIS
EVENING. STRONG WARM ADVECTION NORTH OF THE BOUNDARY HAS
RESULTED IN RAPID EXPANSION OF MID LEVEL CLOUDS...WITH RADAR
RETURNS INCREASING. HOWEVER...WITH VERY DRY LOW LEVELS IN
PLACE...MOST OF THIS RAIN IS NOT REACHING THE GROUND WITH VFR
CONDS EXPECTED TO PREDOMINATE AS A RESULT. HRRR ALONG WITH THE
HOPWRF CONTINUE TO SHOW ENOUGH MOISTENING OCCURRING OVER WRN WI TO
ALLOW FOR SOME LIGHT RAIN TO REACH THE SFC. ONLY CHANGE FROM 00Z
TAFS WAS TO NARROW TEMPO SHRA WINDOW AT RNH/EAU. DURING THE DAY
FRIDAY...A WEAK SFC TROUGH WILL WORK INTO THE AREA...WHICH WILL
RESULT IN A DECREASE OF THE WINDS DURING THE DAY AS THEY VEER
AROUND TO THE W-NW.

KMSP...VFR CONDITIONS EXPECTED THROUGHOUT AS DRY LOW LEVELS KEEP
RAIN FROM REACHING THE SFC. MINIMAL COLD ADVECTION EXPECTED BEHIND
THE MORNING WIND SHIFT...WHICH WILL KEEP ANY LOW CLOUDS FROM
FORMING IN ITS WAKE. AS LLJ MOVES OVERHEAD TONIGHT...MAY HAVE SOME
WIND SHEAR...BUT WITH MINIMAL WIND SHIFT HAVE CONTINUED TO NOT
MENTION IT.

/OUTLOOK FOR KMSP/
SAT...VFR. SSW WINDS 10 KTS.
SUN...VFR. SSW WINDS 15-20 KTS.
MON...MVFR OR LOWER POSSIBLE WITH CHANE -SHRA/-TSRA. WIND SE 5-10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...CLF
LONG TERM...LS
AVIATION...MPG







AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 1205 PM CDT FRI APR 26 2013

.UPDATE...
ISSUED AT 908 AM CDT FRI APR 26 2013

INCREASED POPS TODAY AS FIRST WAVE OF RAIN SHOWERS STEADILY MARCH
NORTHEAST INTO THE FORECAST AREA. DRY LOW LEVELS ARE FIGHTING A
LOSING BATTLE AND MEASURABLE PRECIPITATION HAS BEEN OBSERVED AS
FAR EAST AS FARMINGTON ALREADY. COULD SEE A BREAK ALONG THE I-70
CORRIDOR THIS AFTERNOON BEFORE ROUND NUMBER TWO OVERSPREADS THE
AREA IN ASSOCIATION WITH THE MAIN SHORTWAVE CURRENTLY LOCATED
OVER COLORADO.

CVKING

&&

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 353 AM CDT FRI APR 26 2013

THE PRIMARY FCST ISSUE FOR TODAY IS PCPN COVERAGE.

EARLY MORNING WATER VAPOR IMAGERY AND RUC 1.5 PVU ANALYSES DEPICTED
A COMPACT VORT MAX OVER MN AS WELL AS A SHORTWAVE NEAR THE FOUR
CORNERS REGION. A BROAD AREA OF SHRA/TSRA HAS DEVELOPED ACROSS PARTS
OF KS/OK/MO/AR IN RESPONSE TO A COMBINATION OF H9 FRONTOGENESIS AND
H85-H7 MOISTURE CONVERGENCE FM THE LLJ AHEAD OF THE FOUR CORNERS
SHORTWAVE. THIS 40-50KT SWLY LLJ /PER AREA VWP AND PROFILER OBS/ WAS
TRANSPORTING MOISTURE INTO THE AREA AND LEADING TO AN INCREASE IN
PCPN COVERAGE. ALTHOUGH MODELS GENERALLY SHOW A DECREASE IN THE LLJ
THROUGH MID MORNING ACROSS MO/IL...THEY ALSO SHOW PERSISTENT AREAS
OF ISENTROPIC ASCENT ALONG THE 295-305K SFCS /ESPECIALLY ACROSS THE
SWRN CWA/ ALONG WITH AREAS OF INCREASED FRONTOGENESIS ALOFT.
ALTHOUGH THE BEST FORCING FOR LARGE SCALE ASCENT WILL NOT ARRIVE
UNTIL LATER TONIGHT AND THE LOW LEVEL AIR MASS WILL INITIALLY BE
SOMEWHAT DRY...THE AFOREMENTIONED LIFTING MECHANISMS APPEAR
SUFFICIENT TO CONTINUE POPS FOR SCT-INTERMITTENT SHRA TODAY.

42

.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 AM CDT FRI APR 26 2013

(TONIGHT - SATURDAY)

A LARGELY NEUTRAL UPPER LEVEL FLOW WILL EXIST THRU SATURDAY...BUT
THIS PERIOD WILL BE MOST MARKED BY A STRONG SHORTWAVE SLOWLY PASSING
THRU.  THE PROGRESSION OF THIS SYSTEM THRU THE BI-STATE WILL BE
SLOW...WITH IT NOT EXPECTED TO PULL AWAY UNTIL LATE SATURDAY NIGHT.
UNTIL SUNDAY...LOOK FOR CLOUDY SKIES WITH HI RAIN PROBS...EVEN
THOUGH SOME AREAS MAY ONLY RECEIVE A FEW HUNDREDTHS WITH EXPECTED
NATURE OF PCPN FOR MUCH OF THIS EVENT TO BE SHOWERY.

MAIN AREAS TO KEY ON FOR RAIN TONIGHT WILL BE WHAT SHOULD BE A
PERSISTENTLY STRONG REGION OF WAA AND H850-700 FRONTOGENESIS OVER
SERN MO AND FAR SRN IL WHICH WILL REPRESENT THE BEST CHANCES FOR
MEASURABLE...BUT A MORE BROADSCALE REGION OF MID LEVEL LIFT SHOULD
ALSO WORK IN FOR THE REMAINDER OF THE AREA...ESPECIALLY W OF THE MS
RIVER FOR ADDITIONAL LIGHT RAIN AMOUNTS.

ON SATURDAY THE MEAT OF THE SYSTEM MOVES THRU WITH GENERALLY WEAK
YET DEEP LIFT THRU A MOIST COLUMN...AND BUMPED POPS TO LIKELY FOR
WIDESPREAD LIGHT RAINFALL AMOUNTS.  THIS FINALLY BEGINS TO EXIT
SATURDAY NIGHT WITH MOISTURE SLOWLY SCOURING OUT ALTHOUGH COULD SEE
SHRA SIMPLY BE REPLACED BY DRIZZLE EARLY SUNDAY MORNING WITH LO
CLOUDS BEING THE MOST STUBBORN OF ALL TO LEAVE.

THE WARMER MAV MOS IS PREFERRED FOR MINS TONIGHT...WHILE WENT WITH
THE COOLER MET MOS FOR MAXES SATURDAY TO PROMOTE A LO DIURNAL SWING
WITH WHAT SHOULD BE THICK AND LO CLOUD COVER.  AGAIN PREFERRED
WARMER MAV MOS FOR SATURDAY NIGHT MINS.

(SUNDAY - TUESDAY)

UPPER LEVEL LONGWAVE RIDGE WILL BUILD OVER ERN NOAM WHILE A TROF
DIGS IN THE W...RESULTING IN A WARM AND DRY PERIOD...WITH TEMPS
PUSHING ABOVE AVERAGE FOR A COUPLE OF DAYS AT LEAST.  WHILE DID
UNDERCUT MOS MAX TEMPS ON SUNDAY DUE TO WHAT SHOULD BE STUBBORN LO
CLOUD HANGING AROUND AND FINALLY LEAVING...MONDAY AND TUESDAY ARE
EXPECTED TO FEATURE PLENTY OF SUNSHINE AND A DECENT S FLOW WITH
RISING H500 HEIGHTS OVERHEAD.  FCST H850/H900 TEMPS...IF THEY PAN
OUT...WILL RESULT IN 75-80F FOR MONDAY AND AROUND 78-82F FOR
TUESDAY.

BUILDING RIDGE WILL EFFECTIVELY DEFLECT ANY SYSTEMS TO OUR N AND
SHOULD KEEP OUR REGION DRY.

(WEDNESDAY - THURSDAY)

ALL OF THIS IS SHORT-LIVED...WITH THE UPPER LEVEL ERN NOAM RIDGE TO
BREAKDOWN EITHER WEDNESDAY OR THURSDAY DEPENDING ON THE MODEL AND
WILL BE ACCOMPANIED BY A STOUT CDFNT BACKED BY A STRONG CANADIAN
AIRMASS.  THE ECMWF PREFERS A SLOWER TIMING ON THURS WHILE THE GFS
FAVORS WEDNESDAY.  HAVE STRETCHED POPS FOR WED-THU TO COVER TIMING
DIFFS WITH FRONT AND DID NOT HIT THE COLD AIR AS MUCH ON THURSDAY
FOR THE SAME REASONS.

TES

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1156 AM CDT FRI APR 26 2013

LIGHT RAIN SHOWERS CONTINUE TO DEVELOP ACROSS THE FORECAST AREA
EARLY THIS AFTERNOON. CONDITIONS SHOULD REMAIN VFR THROUGH THE
AFTERNOON OUTSIDE OF HEAVIER RAIN WHICH IS LOCATED ACROSS THE FAR
SOUTHERN PART OF THE CWA. GENERALLY BELIEVE THAT THE MAIN THRUST
OF RAIN SHOULD COME THIS EVENING AND INTO THE OVERNIGHT AS MAIN
UPPER LEVEL ENERGY PUSH INTO THE REGION. HAVE BROUGHT CEILING DOWN
TO MVFR CATEGORY BUT AM NOT SOLD ON IFR CONDITIONS YET...WOULD
RATHER TAKE A WAIT AND SEE APPROACH. OTHERWISE...WITH UPPER LEVEL
SYSTEM MOVING OVERHEAD ON SATURDAY...COULD SEE SHOWERS AND LOWER
CEILINGS LINGER THROUGH THE DAY. SOUTH WIND WILL BECOME EAST.

SPECIFICS FOR KSTL...

ISOLATED TO SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE THIS
AFTERNOON WITH A RAMPING UP OF COVERAGE AND INTENSITY THIS EVENING
AS UPPER LEVEL SYSTEM APPROACHES. COULD BE A PERIOD OF IFR
CONDITIONS IN HEAVIER RAIN...BUT WILL HAVE TO NOWCAST THIS BASED
ON RADAR AS WE GET CLOSER. OTHERWISE...CEILING TO LOWER TO MVFR
AND SHOWERS TO CONTINUE INTO SATURDAY WITH UPPER LOW TRACKING
OVERHEAD.

CVKING

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

 913 AM CDT FRI APR 26 2013

.UPDATE...
ISSUED AT 908 AM CDT FRI APR 26 2013

INCREASED POPS TODAY AS FIRST WAVE OF RAIN SHOWERS STEADILY MARCH
NORTHEAST INTO THE FORECAST AREA. DRY LOW LEVELS ARE FIGHTING A
LOSING BATTLE AND MEASURABLE PRECIPITATION HAS BEEN OBSERVED AS
FAR EAST AS FARMINGTON ALREADY. COULD SEE A BREAK ALONG THE I-70
CORRIDOR THIS AFTERNOON BEFORE ROUND NUMBER TWO OVERSPREADS THE
AREA IN ASSOCIATION WITH THE MAIN SHORTWAVE CURRENTLY LOCATED
OVER COLORADO.

CVKING

&&

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 353 AM CDT FRI APR 26 2013

THE PRIMARY FCST ISSUE FOR TODAY IS PCPN COVERAGE.

EARLY MORNING WATER VAPOR IMAGERY AND RUC 1.5 PVU ANALYSES DEPICTED
A COMPACT VORT MAX OVER MN AS WELL AS A SHORTWAVE NEAR THE FOUR
CORNERS REGION. A BROAD AREA OF SHRA/TSRA HAS DEVELOPED ACROSS PARTS
OF KS/OK/MO/AR IN RESPONSE TO A COMBINATION OF H9 FRONTOGENESIS AND
H85-H7 MOISTURE CONVERGENCE FM THE LLJ AHEAD OF THE FOUR CORNERS
SHORTWAVE. THIS 40-50KT SWLY LLJ /PER AREA VWP AND PROFILER OBS/ WAS
TRANSPORTING MOISTURE INTO THE AREA AND LEADING TO AN INCREASE IN
PCPN COVERAGE. ALTHOUGH MODELS GENERALLY SHOW A DECREASE IN THE LLJ
THROUGH MID MORNING ACROSS MO/IL...THEY ALSO SHOW PERSISTENT AREAS
OF ISENTROPIC ASCENT ALONG THE 295-305K SFCS /ESPECIALLY ACROSS THE
SWRN CWA/ ALONG WITH AREAS OF INCREASED FRONTOGENESIS ALOFT.
ALTHOUGH THE BEST FORCING FOR LARGE SCALE ASCENT WILL NOT ARRIVE
UNTIL LATER TONIGHT AND THE LOW LEVEL AIR MASS WILL INITIALLY BE
SOMEWHAT DRY...THE AFOREMENTIONED LIFTING MECHANISMS APPEAR
SUFFICIENT TO CONTINUE POPS FOR SCT-INTERMITTENT SHRA TODAY.

42

.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 AM CDT FRI APR 26 2013

(TONIGHT - SATURDAY)

A LARGELY NEUTRAL UPPER LEVEL FLOW WILL EXIST THRU SATURDAY...BUT
THIS PERIOD WILL BE MOST MARKED BY A STRONG SHORTWAVE SLOWLY PASSING
THRU.  THE PROGRESSION OF THIS SYSTEM THRU THE BI-STATE WILL BE
SLOW...WITH IT NOT EXPECTED TO PULL AWAY UNTIL LATE SATURDAY NIGHT.
UNTIL SUNDAY...LOOK FOR CLOUDY SKIES WITH HI RAIN PROBS...EVEN
THOUGH SOME AREAS MAY ONLY RECEIVE A FEW HUNDREDTHS WITH EXPECTED
NATURE OF PCPN FOR MUCH OF THIS EVENT TO BE SHOWERY.

MAIN AREAS TO KEY ON FOR RAIN TONIGHT WILL BE WHAT SHOULD BE A
PERSISTENTLY STRONG REGION OF WAA AND H850-700 FRONTOGENESIS OVER
SERN MO AND FAR SRN IL WHICH WILL REPRESENT THE BEST CHANCES FOR
MEASURABLE...BUT A MORE BROADSCALE REGION OF MID LEVEL LIFT SHOULD
ALSO WORK IN FOR THE REMAINDER OF THE AREA...ESPECIALLY W OF THE MS
RIVER FOR ADDITIONAL LIGHT RAIN AMOUNTS.

ON SATURDAY THE MEAT OF THE SYSTEM MOVES THRU WITH GENERALLY WEAK
YET DEEP LIFT THRU A MOIST COLUMN...AND BUMPED POPS TO LIKELY FOR
WIDESPREAD LIGHT RAINFALL AMOUNTS.  THIS FINALLY BEGINS TO EXIT
SATURDAY NIGHT WITH MOISTURE SLOWLY SCOURING OUT ALTHOUGH COULD SEE
SHRA SIMPLY BE REPLACED BY DRIZZLE EARLY SUNDAY MORNING WITH LO
CLOUDS BEING THE MOST STUBBORN OF ALL TO LEAVE.

THE WARMER MAV MOS IS PREFERRED FOR MINS TONIGHT...WHILE WENT WITH
THE COOLER MET MOS FOR MAXES SATURDAY TO PROMOTE A LO DIURNAL SWING
WITH WHAT SHOULD BE THICK AND LO CLOUD COVER.  AGAIN PREFERRED
WARMER MAV MOS FOR SATURDAY NIGHT MINS.

(SUNDAY - TUESDAY)

UPPER LEVEL LONGWAVE RIDGE WILL BUILD OVER ERN NOAM WHILE A TROF
DIGS IN THE W...RESULTING IN A WARM AND DRY PERIOD...WITH TEMPS
PUSHING ABOVE AVERAGE FOR A COUPLE OF DAYS AT LEAST.  WHILE DID
UNDERCUT MOS MAX TEMPS ON SUNDAY DUE TO WHAT SHOULD BE STUBBORN LO
CLOUD HANGING AROUND AND FINALLY LEAVING...MONDAY AND TUESDAY ARE
EXPECTED TO FEATURE PLENTY OF SUNSHINE AND A DECENT S FLOW WITH
RISING H500 HEIGHTS OVERHEAD.  FCST H850/H900 TEMPS...IF THEY PAN
OUT...WILL RESULT IN 75-80F FOR MONDAY AND AROUND 78-82F FOR
TUESDAY.

BUILDING RIDGE WILL EFFECTIVELY DEFLECT ANY SYSTEMS TO OUR N AND
SHOULD KEEP OUR REGION DRY.

(WEDNESDAY - THURSDAY)

ALL OF THIS IS SHORT-LIVED...WITH THE UPPER LEVEL ERN NOAM RIDGE TO
BREAKDOWN EITHER WEDNESDAY OR THURSDAY DEPENDING ON THE MODEL AND
WILL BE ACCOMPANIED BY A STOUT CDFNT BACKED BY A STRONG CANADIAN
AIRMASS.  THE ECMWF PREFERS A SLOWER TIMING ON THURS WHILE THE GFS
FAVORS WEDNESDAY.  HAVE STRETCHED POPS FOR WED-THU TO COVER TIMING
DIFFS WITH FRONT AND DID NOT HIT THE COLD AIR AS MUCH ON THURSDAY
FOR THE SAME REASONS.

TES

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 605 AM CDT FRI APR 26 2013

AN AREA OF SHOWERS WITH EMBEDDED THUNDERSTORMS HAS DEVELOPED
ACROSS THE REGION THIS MORNING AHEAD OF AN UPPER LEVEL
DISTURBANCE. SHOWERS ARE EXPECTED TO SPREAD EWD WITH TIME TODAY
HOWEVER THE INITIALLY DRY AIR AT LOW LEVELS WILL DELAY THE ONSET
OF PCPN AT THE GROUND. IT LOOKS LIKE THERE WILL BE A BREAK IN THE
RAIN FOR A FEW HOURS DURING THE AFTN OR EVENING BEFORE THE NEXT
WAVE OF PCPN DVLPS AND REACHES THE TERMINALS. UPSTREAM OBS SHOW
THAT IT HAS BEEN DIFFICULT FOR CONDITIONS TO FALL BELOW VFR DUE TO
THE DRY AIR AND HIGH CLOUD BASES. AFTER A DAY OF GRADUAL TOP-DOWN
SATURATION...CONDITIONS ARE EXPECTED TO DETERIORATE TO MVFR AND
POSSIBLY IFR WITH THE NEXT WAVE OF PCPN WHEN IT OCCURS LATER
TONIGHT. INITIALLY SLY WINDS WILL BACK AND BECOME NEARLY ELY BY
THE END OF THE TAF PD.

SPECIFICS FOR KSTL...AN AREA OF SHOWERS WITH EMBEDDED
THUNDERSTORMS HAS DEVELOPED AHEAD OF AN UPPER LEVEL DISTURBANCE.
PCPN IS EXPECTED TO REACH KSTL WITHIN THE NEXT SEVERAL HOURS
HOWEVER UPSTREAM OBS SHOW THAT IT HAS BEEN DIFFICULT FOR
CONDITIONS TO FALL BELOW VFR DUE TO THE DRY AIR AND HIGH CLOUD
BASES. ANOTHER WAVE OF PCPN IS EXPECTED TO DVLP LATER TONIGHT AS
THE UPPER LEVEL DISTURBANCE APPROACHES KSTL. CONDITIONS WILL
PROBABLY DETERIORATE TO MVFR AND POSSIBLY IFR IN THE SECOND WAVE
DEPENDING ON HOW MUCH SATURATION OCCURS DURING THE DAY TODAY.
INITIALLY SLY WINDS WILL BACK AND BECOME NEARLY ELY BY THE END OF
THE TAF PD.

KANOFSKY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 629 AM CDT FRI APR 26 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 353 AM CDT FRI APR 26 2013

THE PRIMARY FCST ISSUE FOR TODAY IS PCPN COVERAGE.

EARLY MORNING WATER VAPOR IMAGERY AND RUC 1.5 PVU ANALYSES DEPICTED
A COMPACT VORT MAX OVER MN AS WELL AS A SHORTWAVE NEAR THE FOUR
CORNERS REGION. A BROAD AREA OF SHRA/TSRA HAS DEVELOPED ACROSS PARTS
OF KS/OK/MO/AR IN RESPONSE TO A COMBINATION OF H9 FRONTOGENESIS AND
H85-H7 MOISTURE CONVERGENCE FM THE LLJ AHEAD OF THE FOUR CORNERS
SHORTWAVE. THIS 40-50KT SWLY LLJ /PER AREA VWP AND PROFILER OBS/ WAS
TRANSPORTING MOISTURE INTO THE AREA AND LEADING TO AN INCREASE IN
PCPN COVERAGE. ALTHOUGH MODELS GENERALLY SHOW A DECREASE IN THE LLJ
THROUGH MID MORNING ACROSS MO/IL...THEY ALSO SHOW PERSISTENT AREAS
OF ISENTROPIC ASCENT ALONG THE 295-305K SFCS /ESPECIALLY ACROSS THE
SWRN CWA/ ALONG WITH AREAS OF INCREASED FRONTOGENESIS ALOFT.
ALTHOUGH THE BEST FORCING FOR LARGE SCALE ASCENT WILL NOT ARRIVE
UNTIL LATER TONIGHT AND THE LOW LEVEL AIR MASS WILL INITIALLY BE
SOMEWHAT DRY...THE AFOREMENTIONED LIFTING MECHANISMS APPEAR
SUFFICIENT TO CONTINUE POPS FOR SCT-INTERMITTENT SHRA TODAY.

42

.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 AM CDT FRI APR 26 2013

(TONIGHT - SATURDAY)

A LARGELY NEUTRAL UPPER LEVEL FLOW WILL EXIST THRU SATURDAY...BUT
THIS PERIOD WILL BE MOST MARKED BY A STRONG SHORTWAVE SLOWLY PASSING
THRU.  THE PROGRESSION OF THIS SYSTEM THRU THE BI-STATE WILL BE
SLOW...WITH IT NOT EXPECTED TO PULL AWAY UNTIL LATE SATURDAY NIGHT.
UNTIL SUNDAY...LOOK FOR CLOUDY SKIES WITH HI RAIN PROBS...EVEN
THOUGH SOME AREAS MAY ONLY RECEIVE A FEW HUNDREDTHS WITH EXPECTED
NATURE OF PCPN FOR MUCH OF THIS EVENT TO BE SHOWERY.

MAIN AREAS TO KEY ON FOR RAIN TONIGHT WILL BE WHAT SHOULD BE A
PERSISTENTLY STRONG REGION OF WAA AND H850-700 FRONTOGENESIS OVER
SERN MO AND FAR SRN IL WHICH WILL REPRESENT THE BEST CHANCES FOR
MEASURABLE...BUT A MORE BROADSCALE REGION OF MID LEVEL LIFT SHOULD
ALSO WORK IN FOR THE REMAINDER OF THE AREA...ESPECIALLY W OF THE MS
RIVER FOR ADDITIONAL LIGHT RAIN AMOUNTS.

ON SATURDAY THE MEAT OF THE SYSTEM MOVES THRU WITH GENERALLY WEAK
YET DEEP LIFT THRU A MOIST COLUMN...AND BUMPED POPS TO LIKELY FOR
WIDESPREAD LIGHT RAINFALL AMOUNTS.  THIS FINALLY BEGINS TO EXIT
SATURDAY NIGHT WITH MOISTURE SLOWLY SCOURING OUT ALTHOUGH COULD SEE
SHRA SIMPLY BE REPLACED BY DRIZZLE EARLY SUNDAY MORNING WITH LO
CLOUDS BEING THE MOST STUBBORN OF ALL TO LEAVE.

THE WARMER MAV MOS IS PREFERRED FOR MINS TONIGHT...WHILE WENT WITH
THE COOLER MET MOS FOR MAXES SATURDAY TO PROMOTE A LO DIURNAL SWING
WITH WHAT SHOULD BE THICK AND LO CLOUD COVER.  AGAIN PREFERRED
WARMER MAV MOS FOR SATURDAY NIGHT MINS.

(SUNDAY - TUESDAY)

UPPER LEVEL LONGWAVE RIDGE WILL BUILD OVER ERN NOAM WHILE A TROF
DIGS IN THE W...RESULTING IN A WARM AND DRY PERIOD...WITH TEMPS
PUSHING ABOVE AVERAGE FOR A COUPLE OF DAYS AT LEAST.  WHILE DID
UNDERCUT MOS MAX TEMPS ON SUNDAY DUE TO WHAT SHOULD BE STUBBORN LO
CLOUD HANGING AROUND AND FINALLY LEAVING...MONDAY AND TUESDAY ARE
EXPECTED TO FEATURE PLENTY OF SUNSHINE AND A DECENT S FLOW WITH
RISING H500 HEIGHTS OVERHEAD.  FCST H850/H900 TEMPS...IF THEY PAN
OUT...WILL RESULT IN 75-80F FOR MONDAY AND AROUND 78-82F FOR
TUESDAY.

BUILDING RIDGE WILL EFFECTIVELY DEFLECT ANY SYSTEMS TO OUR N AND
SHOULD KEEP OUR REGION DRY.

(WEDNESDAY - THURSDAY)

ALL OF THIS IS SHORT-LIVED...WITH THE UPPER LEVEL ERN NOAM RIDGE TO
BREAKDOWN EITHER WEDNESDAY OR THURSDAY DEPENDING ON THE MODEL AND
WILL BE ACCOMPANIED BY A STOUT CDFNT BACKED BY A STRONG CANADIAN
AIRMASS.  THE ECMWF PREFERS A SLOWER TIMING ON THURS WHILE THE GFS
FAVORS WEDNESDAY.  HAVE STRETCHED POPS FOR WED-THU TO COVER TIMING
DIFFS WITH FRONT AND DID NOT HIT THE COLD AIR AS MUCH ON THURSDAY
FOR THE SAME REASONS.

TES

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 605 AM CDT FRI APR 26 2013

AN AREA OF SHOWERS WITH EMBEDDED THUNDERSTORMS HAS DEVELOPED
ACROSS THE REGION THIS MORNING AHEAD OF AN UPPER LEVEL
DISTURBANCE. SHOWERS ARE EXPECTED TO SPREAD EWD WITH TIME TODAY
HOWEVER THE INITIALLY DRY AIR AT LOW LEVELS WILL DELAY THE ONSET
OF PCPN AT THE GROUND. IT LOOKS LIKE THERE WILL BE A BREAK IN THE
RAIN FOR A FEW HOURS DURING THE AFTN OR EVENING BEFORE THE NEXT
WAVE OF PCPN DVLPS AND REACHES THE TERMINALS. UPSTREAM OBS SHOW
THAT IT HAS BEEN DIFFICULT FOR CONDITIONS TO FALL BELOW VFR DUE TO
THE DRY AIR AND HIGH CLOUD BASES. AFTER A DAY OF GRADUAL TOP-DOWN
SATURATION...CONDITIONS ARE EXPECTED TO DETERIORATE TO MVFR AND
POSSIBLY IFR WITH THE NEXT WAVE OF PCPN WHEN IT OCCURS LATER
TONIGHT. INITIALLY SLY WINDS WILL BACK AND BECOME NEARLY ELY BY
THE END OF THE TAF PD.

SPECIFICS FOR KSTL...AN AREA OF SHOWERS WITH EMBEDDED
THUNDERSTORMS HAS DEVELOPED AHEAD OF AN UPPER LEVEL DISTURBANCE.
PCPN IS EXPECTED TO REACH KSTL WITHIN THE NEXT SEVERAL HOURS
HOWEVER UPSTREAM OBS SHOW THAT IT HAS BEEN DIFFICULT FOR
CONDITIONS TO FALL BELOW VFR DUE TO THE DRY AIR AND HIGH CLOUD
BASES. ANOTHER WAVE OF PCPN IS EXPECTED TO DVLP LATER TONIGHT AS
THE UPPER LEVEL DISTURBANCE APPROACHES KSTL. CONDITIONS WILL
PROBABLY DETERIORATE TO MVFR AND POSSIBLY IFR IN THE SECOND WAVE
DEPENDING ON HOW MUCH SATURATION OCCURS DURING THE DAY TODAY.
INITIALLY SLY WINDS WILL BACK AND BECOME NEARLY ELY BY THE END OF
THE TAF PD.

KANOFSKY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION

NWS ST LOUIS MO

 353 AM CDT FRI APR 26 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 353 AM CDT FRI APR 26 2013

THE PRIMARY FCST ISSUE FOR TODAY IS PCPN COVERAGE.

EARLY MORNING WATER VAPOR IMAGERY AND RUC 1.5 PVU ANALYSES DEPICTED
A COMPACT VORT MAX OVER MN AS WELL AS A SHORTWAVE NEAR THE FOUR
CORNERS REGION. A BROAD AREA OF SHRA/TSRA HAS DEVELOPED ACROSS PARTS
OF KS/OK/MO/AR IN RESPONSE TO A COMBINATION OF H9 FRONTOGENESIS AND
H85-H7 MOISTURE CONVERGENCE FM THE LLJ AHEAD OF THE FOUR CORNERS
SHORTWAVE. THIS 40-50KT SWLY LLJ /PER AREA VWP AND PROFILER OBS/ WAS
TRANSPORTING MOISTURE INTO THE AREA AND LEADING TO AN INCREASE IN
PCPN COVERAGE. ALTHOUGH MODELS GENERALLY SHOW A DECREASE IN THE LLJ
THROUGH MID MORNING ACROSS MO/IL...THEY ALSO SHOW PERSISTENT AREAS
OF ISENTROPIC ASCENT ALONG THE 295-305K SFCS /ESPECIALLY ACROSS THE
SWRN CWA/ ALONG WITH AREAS OF INCREASED FRONTOGENESIS ALOFT.
ALTHOUGH THE BEST FORCING FOR LARGE SCALE ASCENT WILL NOT ARRIVE
UNTIL LATER TONIGHT AND THE LOW LEVEL AIR MASS WILL INITIALLY BE
SOMEWHAT DRY...THE AFOREMENTIONED LIFTING MECHANISMS APPEAR
SUFFICIENT TO CONTINUE POPS FOR SCT-INTERMITTENT SHRA TODAY.

42

.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 AM CDT FRI APR 26 2013

(TONIGHT - SATURDAY)

A LARGELY NEUTRAL UPPER LEVEL FLOW WILL EXIST THRU SATURDAY...BUT
THIS PERIOD WILL BE MOST MARKED BY A STRONG SHORTWAVE SLOWLY PASSING
THRU.  THE PROGRESSION OF THIS SYSTEM THRU THE BI-STATE WILL BE
SLOW...WITH IT NOT EXPECTED TO PULL AWAY UNTIL LATE SATURDAY NIGHT.
UNTIL SUNDAY...LOOK FOR CLOUDY SKIES WITH HI RAIN PROBS...EVEN
THOUGH SOME AREAS MAY ONLY RECEIVE A FEW HUNDREDTHS WITH EXPECTED
NATURE OF PCPN FOR MUCH OF THIS EVENT TO BE SHOWERY.

MAIN AREAS TO KEY ON FOR RAIN TONIGHT WILL BE WHAT SHOULD BE A
PERSISTENTLY STRONG REGION OF WAA AND H850-700 FRONTOGENESIS OVER
SERN MO AND FAR SRN IL WHICH WILL REPRESENT THE BEST CHANCES FOR
MEASURABLE...BUT A MORE BROADSCALE REGION OF MID LEVEL LIFT SHOULD
ALSO WORK IN FOR THE REMAINDER OF THE AREA...ESPECIALLY W OF THE MS
RIVER FOR ADDITIONAL LIGHT RAIN AMOUNTS.

ON SATURDAY THE MEAT OF THE SYSTEM MOVES THRU WITH GENERALLY WEAK
YET DEEP LIFT THRU A MOIST COLUMN...AND BUMPED POPS TO LIKELY FOR
WIDESPREAD LIGHT RAINFALL AMOUNTS.  THIS FINALLY BEGINS TO EXIT
SATURDAY NIGHT WITH MOISTURE SLOWLY SCOURING OUT ALTHOUGH COULD SEE
SHRA SIMPLY BE REPLACED BY DRIZZLE EARLY SUNDAY MORNING WITH LO
CLOUDS BEING THE MOST STUBBORN OF ALL TO LEAVE.

THE WARMER MAV MOS IS PREFERRED FOR MINS TONIGHT...WHILE WENT WITH
THE COOLER MET MOS FOR MAXES SATURDAY TO PROMOTE A LO DIURNAL SWING
WITH WHAT SHOULD BE THICK AND LO CLOUD COVER.  AGAIN PREFERRED
WARMER MAV MOS FOR SATURDAY NIGHT MINS.

(SUNDAY - TUESDAY)

UPPER LEVEL LONGWAVE RIDGE WILL BUILD OVER ERN NOAM WHILE A TROF
DIGS IN THE W...RESULTING IN A WARM AND DRY PERIOD...WITH TEMPS
PUSHING ABOVE AVERAGE FOR A COUPLE OF DAYS AT LEAST.  WHILE DID
UNDERCUT MOS MAX TEMPS ON SUNDAY DUE TO WHAT SHOULD BE STUBBORN LO
CLOUD HANGING AROUND AND FINALLY LEAVING...MONDAY AND TUESDAY ARE
EXPECTED TO FEATURE PLENTY OF SUNSHINE AND A DECENT S FLOW WITH
RISING H500 HEIGHTS OVERHEAD.  FCST H850/H900 TEMPS...IF THEY PAN
OUT...WILL RESULT IN 75-80F FOR MONDAY AND AROUND 78-82F FOR
TUESDAY.

BUILDING RIDGE WILL EFFECTIVELY DEFLECT ANY SYSTEMS TO OUR N AND
SHOULD KEEP OUR REGION DRY.

(WEDNESDAY - THURSDAY)

ALL OF THIS IS SHORT-LIVED...WITH THE UPPER LEVEL ERN NOAM RIDGE TO
BREAKDOWN EITHER WEDNESDAY OR THURSDAY DEPENDING ON THE MODEL AND
WILL BE ACCOMPANIED BY A STOUT CDFNT BACKED BY A STRONG CANADIAN
AIRMASS.  THE ECMWF PREFERS A SLOWER TIMING ON THURS WHILE THE GFS
FAVORS WEDNESDAY.  HAVE STRETCHED POPS FOR WED-THU TO COVER TIMING
DIFFS WITH FRONT AND DID NOT HIT THE COLD AIR AS MUCH ON THURSDAY
FOR THE SAME REASONS.

TES

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1127 PM CDT THU APR 25 2013

HIGH-LEVEL CLOUD DECK HAS OVERSPREAD MID-MISSISSIPPI VALLEY AHEAD
OF SYSTEM EJECTING OUT OF THE DESERT SOUTHWEST. AREA OF SHOWERS
HAS DEVELOPED OVER CENTRAL KANSAS AND THIS AREA SHOULD SLOWLY PUSH
EASTWARD OVERNIGHT WITHIN ZONAL FLOW. STILL THINKING THIS SHOULD
TRANSLATE ACROSS THE INTERSTATE CORRIDOR IN MISSOURI THROUGH LATE
MORNING TOMORROW. STILL SOME UNCERTAINTY ON HOW WELL THIS HOLDS
TOGETHER WITH EASTWARD EXTENT AS LOW-LEVEL ENVIRONMENT WILL BE
DRIER IN CLOSER PROXIMITY SURFACE RIDGE AXIS...ESPECIALLY GIVEN
FARILY WEAK UPPER-AIR FORCING. NWP GUIDANCE DIVERGES FURTHER LATE
FRIDAY AND FRIDAY NIGHT WITH NAM FURTHER NORTH WITH AREA OF
PRECIPITATION THAN GFS. DIFFERENCES ARE DUE PRIMARILY TO PLACEMENT
OF LOW-LEVEL JET/MOISTURE CONVERGENCE...NAM BEING FURTHER
NORTH/COLLOCATED WITH UPPER-AIR FORCING AND GFS CLSOER TO
MISSOURI/ARKANSAS BORDER. WITH STRONG UPPER-AIR FORCING FOR ASCENT
MOVING IN...LEANED TOWARD FURTHER NORTH PLACEMENT OF QPF AXIS
YIELDING -SHRA AT KCOU AND METRO TAF SITES ALONG WITH MVFR
CEILINGS/VISIBILITIES. AS FOR WINDS...THEY WILL REMAIN OUT OF THE
SOUTH/SOUTHEAST THROUGH THE PERIOD WITH THE STRONGEST WINDS DURING
THE DAY TOMORROW AS PRESSURE GRADIENT INCREASES.

SPECIFICS FOR KSTL...HIGH-LEVEL CLOUD DECK HAS OVERSPREAD MID-
MISSISSIPPI VALLEY AHEAD OF SYSTEM EJECTING OUT OF THE DESERT
SOUTHWEST. AREA OF SHOWERS HAS DEVELOPED OVER CENTRAL KANSAS AND
THIS AREA SHOULD SLOWLY PUSH EASTWARD OVERNIGHT WITHIN ZONAL FLOW.
STILL THINKING THIS SHOULD TRANSLATE ACROSS THE INTERSTATE
CORRIDOR IN MISSOURI THROUGH LATE MORNING TOMORROW. STILL SOME
UNCERTAINTY ON HOW WELL THIS HOLDS TOGETHER WITH EASTWARD EXTENT
AS LOW-LEVEL ENVIRONMENT WILL BE DRIER IN CLOSER PROXIMITY SURFACE
RIDGE AXIS...ESPECIALLY GIVEN FARILY WEAK UPPER-AIR FORCING. NWP
GUIDANCE DIVERGES FURTHER LATE FRIDAY AND FRIDAY NIGHT WITH NAM
FURTHER NORTH WITH AREA OF PRECIPITATION THAN GFS. DIFFERENCES ARE
DUE PRIMARILY TO PLACEMENT OF LOW-LEVEL JET/MOISTURE
CONVERGENCE...NAM BEING FURTHER NORTH/COLLOCATED WITH UPPER-AIR
FORCING AND GFS CLSOER TO MISSOURI/ARKANSAS BORDER. WITH STRONG
UPPER-AIR FORCING FOR ASCENT MOVING IN...LEANED TOWARD FURTHER
NORTH PLACEMENT OF QPF AXIS YIELDING -SHRA AT KSTL ALONG WITH MVFR
CEILINGS/VISIBILITIES. AS FOR WINDS...THEY WILL REMAIN OUT OF THE
SOUTH/SOUTHEAST THROUGH THE PERIOD WITH THE STRONGEST WINDS DURING
THE DAY TOMORROW AS PRESSURE GRADIENT INCREASES.

GOSSELIN

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





AREA FORECAST DISCUSSION

NWS OMAHA/VALLEY NE

 621 PM CDT SAT APR 27 2013

.AVIATION...00Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS
THROUGH THE PERIOD. BIGGEST QUESTION REMAINS WHETHER THERE WILL BE
ANY FOG OVERNIGHT. NAM BUFFER SOUNDINGS SUGGEST THERE COULD BE
SOME FOG POTENTIAL AT KOMA/KLNK FROM 10-14Z...WHICH IS ALSO
SUPPORTED BY LATEST RAP GUIDANCE. GFS LAMP FORECASTS SUGGEST THAT
FOG MAY NOT DEVELOP. OPTED TO INCLUDE A TEMPO GROUP AND WILL
MONITOR TRENDS TO SEE HOW IT DEVELOPS. THERE COULD ALSO BE SOME
SHOWERS AND A WIND SHIFT TO THE NORTH NORTHWEST THAT DEVELOP AT
KOFK BY 21/22Z AS A COLD FRONT MOVES INTO THE AREA.

DEWALD

&&

.PREV DISCUSSION... /ISSUED 330 PM CDT SAT APR 27 2013/

SHORT TERM...TONIGHT THROUGH TUESDAY.

TEMPERATURES ARE THE MAIN CONCERN THROUGH THIS PERIOD. HIGH PRESSURE
AT THE SURFACE WILL CONTINUE TO MOVE OFF TO THE EAST WITH
SOUTH/SOUTHWEST LOW LEVEL FLOW ACROSS THE FORECAST AREA FOR TONIGHT
AND MUCH OF SUNDAY. LOWS TONIGHT SHOULD DROP INTO THE 40S. MODEST
MIXING WITH LOW LEVEL THERMAL RIDGE IN PLACE AHEAD OF THE NEXT COLD
FRONT SUNDAY SHOULD ALLOW TEMPERATURES TO TOP OUT IN THE UPPER 70S
AND LOWER 80S...SIMILAR TO PREVIOUS FORECAST. MID 80S ARE NOT OUT OF
THE QUESTION IN SOME LOCATIONS BUT DID NOT MENTION THAT FOR NOW. A
COLD FRONT WILL PUSH INTO OUR FAR NORTHERN ZONES LATE SUNDAY
AFTERNOON OR EVENING. INTRODUCED A SLIGHT CHANCE OF LATE AFTERNOON
THUNDERSTORMS FOR LOCATIONS ALONG OR JUST BEHIND THE WIND SHIFT.
THIS FRONT SHOULD SAG SOUTHWARD SUNDAY NIGHT WITH AT LEAST A SMALL
CHANCE OF SHOWERS OR THUNDERSTORMS EXPECTED ALONG AND BEHIND THE
FRONT CENTRAL AND NORTHERN ZONES.

FOR MONDAY...THE FRONT LIFTS BACK NORTH AS A WARM FRONT AND IT LOOKS
WARM AGAIN. KEPT HIGHS IN THE MID 70S TO AROUND 80. THE CHANCE FOR
PCPN LOOKS LOW MONDAY...SO KEPT POPS BELOW 15 PERCENT. MONDAY NIGHT
SHOULD BE QUITE MILD WITH LOWS IN THE 50S.

TUESDAY IS PROBLEMATIC AS A COLD FRONT PUSHES SOUTHEAST ACROSS THE
AREA. COLDER AIR SHOULD BE ACROSS ABOUT THE NORTHWEST HALF OF THE
AREA BUT EXACT LOCATION OF THE FRONT WILL BE CRITICAL FOR HIGHS. FOR
NOW GENERALLY USED A BLEND OF MODEL SOLUTIONS FOR HIGHS...INCLUDING
SREF OUTPUT. THE RESULT IS A RANGE OF ABOUT 20 DEGREES FROM NORTH TO
SOUTH.

LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.

THE LONGER RANGE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE LARGE
SCALE PATTERN INTO THURSDAY. KEPT CHANCE FOR SHOWERS/THUNDERSTORMS
50-70 PERCENT TUESDAY NIGHT AND 40-60 PERCENT WEDNESDAY WITH DECENT
FORCING ALONG AND BEHIND THE FRONT.

AFTER THAT...FROM WEDNESDAY NIGHT INTO SATURDAY...MODEL SOLUTIONS
ARE IN A LITTLE BETTER AGREEMENT THAN THEY HAVE BEEN PREVIOUSLY WITH
THE LARGE SCALE PATTERN. BUT AS EXPECTED...THERE ARE DIFFERENCES IN
THE DETAILS. A CLOSED LOW AT 500 MB SHOULD BE SOMEWHERE OVER THE
CENTRAL UNITED STATES. THIS PATTERN SHOULD RESULT IN BELOW NORMAL
TEMPERATURES AND AT LEAST SOME CHANCE OF PCPN. JUST HOW HIGH THE
PCPN CHANCES WILL BE WILL DEPEND ON WHERE EXACTLY THE CLOSED LOW
ENDS UP. FOR NOW...ONLY MENTIONED THE POSSIBILITY OF SOME SNOW
MIXED IN WITH THE RAIN ON THE NORTHWEST EDGE OF PCPN AREA FROM
WEDNESDAY INTO WEDNESDAY NIGHT. IF MODEL SOLUTIONS THE NEXT FEW DAYS
REMAIN SIMILAR...THERE COULD ALSO BE SOME SNOW MIXED IN WITH THE
RAIN THURSDAY INTO SATURDAY FOR AT LEAST PARTS OF THE AREA.

MILLER

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$




AREA FORECAST DISCUSSION

NWS HASTINGS NE

 320 PM CDT FRI APR 26 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CDT FRI APR 26 2013

MAIN FOCUS IN THE SHORT TERM WILL CENTER AROUND SLIGHT CHANCES FOR
THUNDERSTORMS AND HIGH TEMPERATURES SATURDAY.

A QUICK SYNOPTIC ANALYSIS REVEALS MOSTLY ZONAL FLOW ACROSS THE
CONUS WITH THE EXCEPTION OF AN OPEN WAVE TROUGH ACROSS THE
ROCKIES. AT THE SURFACE...HIGH PRESSURE REMAINED SITUATED ACROSS
BOTH COASTS WITH A WEAK LOW PRESSURE SYSTEM ACROSS THE TEXAS
PANHANDLE. THE OPEN WAVE BEGAN TO SHIFT JUST SOUTH OF THE PLAINS
THIS MORNING...WHICH BROUGHT SHOWERS AND THUNDERSTORMS TO PORTIONS
OF KANSAS. SATELLITE IMAGERY REVEALS A THICK CLOUD COVER OVER MUCH
OF SOUTHEAST KANSAS AND MISSOURI WITH THINNING CIRRUS DECK ACROSS
SOUTHERN NEBRASKA AND IOWA. A SURFACE TROUGH ASSOCIATED WITH THE
LOW IN THE PANHANDLE ALSO BEGAN SHIFTING ACROSS THE PLAINS THIS
AFTERNOON AS WELL. A STRONG 850 MB JET STREAK ON THE BACKSIDE OF
THIS TROUGH ALSO SHIFTED ACROSS NEBRASKA THIS AFTERNOON. COMBINED
WITH STRONG MIXING...THIS JET STREAK LED TO A BRIEF PERIOD OF
STRONGER WIND GUSTS NEAR 30 MPH AND LOW RH VALUES NEAR 20 PERCENT.
THESE CONDITIONS WERE SEEN OVER A FAIRLY SMALL LOCALIZED AREA
STRETCHING FROM MCCOOK TO ORD WESTWARD.

FOR THE REST OF THE AFTERNOON...SHORT TERM MODELS INDICATE THE
WEAKENING OF THE 850 JET STREAK WHICH SHOULD RELAX WINDS AND HELP
STEADY RH VALUES. CURRENT THINKING IS WINDS WILL REMAIN MARGINAL
AROUND 20 TO 25 MPH FOR THE NEXT FEW HOURS OR SO ESPECIALLY WEST
OF A LINE FROM MCCOOK TO KEARNEY TO ORD BEFORE DECREASING BY LATE
THIS AFTERNOON AND EARLY EVENING.

AS THE SURFACE TROUGH CONTINUES TO SHIFT EASTWARD...MODELS ALSO
HINT AT THE POSSIBILITY FOR SOME ADDITIONAL SHOWER DEVELOPMENT
NEAR THE BOUNDARY...MAINLY SOUTH OF LINE FROM CAMBRIDGE TO
FULLERTON. WITH INSTABILITY PARAMETERS NEAR 300 TO 500 J/KG KEPT
MENTION OF THUNDER IN THE FORECAST FROM 0Z TO 3Z WITH DIMINISHING
INSTABILITY THEREAFTER LIKELY DECREASING THUNDER THREAT. AT THIS
POINT...REALLY THINKING ISOLATED LIGHT SHOWERS WITH MAYBE A RUMBLE
OF THUNDER OR TWO. HRRR AND 4 KM WRF MODEL ALSO IN AGREEMENT WITH
THIS THINKING.

HEADING INTO SATURDAY...THE UPPER LEVEL RIDGE SLOWLY BEGINS TO
BUILD EASTWARD INTO THE PLAINS BEHIND THE TROUGH AXIS. WARMER 850
MB TEMPERATURES WILL ALSO SLIDE INTO THE REGION. SHOULD BE A
FAIRLY NICE AND BRIGHT DAY WITH SURFACE HIGH PRESSURE OVER THE
FORECAST AREA...LIGHT NORTH WINDS AND TEMPERATURES RANGING IN THE
70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CDT FRI APR 26 2013

GUIDANCE SUGGESTS AN OVERALL LACK IN KINEMATIC FORCING SHOULD
PROVIDE DRY CONDITIONS TO OUR AREA SUNDAY INTO SUNDAY EVENING.
DURING THE EARLY MORNING HOURS ON MONDAY HOWEVER...THERE ARE
INDICATIONS OF A WEAK MID LEVEL PERTURBATION MOVING OVER THE
REGION WITH PERHAPS ENOUGH OMEGA FOR PRECIPITATION PRODUCTION.
THAT BEING SAID FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR
AREA...PER THE NAM AND OPERATIONAL GFS...SUGGEST THE LOWER
TROPOSPHERE WILL REMAIN FAIRLY DRY AND AS A RESULT...IT IS
CURRENTLY BELIEVED NOTHING MORE THAN A FEW SPRINKLES WILL BE
REALIZED ACROSS THE AREA EARLY MONDAY MORNING. GIVEN ALL
THIS...WENT AHEAD WITH A SPRINKLE MENTION IN THE
FORECAST...PRIMARILY FOR LOCATIONS ACROSS OUR NORTH/NORTHWEST
WHERE OMEGA IS EXPECTED TO BE STRONGEST. DRY CONDITIONS ARE THEN
FORECAST INTO THE DAY MONDAY AND MONDAY NIGHT AS A LACK IN
KINEMATIC FORCING OVERTAKES THE AREA ONCE AGAIN.

ANOTHER CHANCE AT PRECIPITATION IS THEN FORECAST TUESDAY THROUGH
WEDNESDAY NIGHT AS A MID LEVEL SHORT WAVE IS EXPECTED TO MOVE OVER
PORTIONS OF THE NORTHERN AND CENTRAL PLAINS. AN ASSOCIATED SURFACE
LOW IS ALSO EXPECTED TO MOVE ACROSS PORTIONS OF THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY WITH A LOW LEVEL BAROCLINIC
ZONE FORECAST TO MOVE ACROSS OUR CWA AT SOME POINT DURING THE DAY
TUESDAY. TIMING THE PASSAGE OF THE LOW LEVEL BAROCLINIC ZONE IS
DIFFICULT GIVEN THIS SYSTEM IS STILL 4 DAYS OUT...BUT AT THIS TIME
IT APPEARS LOCATIONS AHEAD OF THE BAROCLINIC ZONE WILL OBSERVE A
SURFACE DEWPOINT IN THE MID TO UPPER 50S. THIS LOW LEVEL
MOISTURE...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE
RATES WITH THE APPROACH OF THE MID LEVEL SHORT WAVE...COULD
POTENTIALLY PROMOTE 0-1KM MLCAPE VALUES ANYWHERE BETWEEN 500J/KG
AND 1500J/KG. INCREASING MID TO UPPER LEVEL FLOW IS ALSO EXPECTED
TO INCREASE DEEP LAYER BULK SHEAR TO BETWEEN 30KTS AND 40KTS.
GIVEN ALL THIS...IT CERTAINLY APPEARS SEVERE WEATHER COULD BE
REALIZED AT LOCATIONS STILL OUT AHEAD OF THE LOW LEVEL BAROCLINIC
ZONE TUESDAY AFTERNOON AND EVENING. AT THIS TIME IT ALSO APPEARS
THE SOUTHEASTERN ONE-THIRD OF OUR CWA STANDS THE BEST CHANCE AT
OBSERVING SEVERE WEATHER AND AS A RESULT...WILL CONTINUE SUCH
WORDING IN THE HWO.

ANY SEVERE WEATHER THAT IS REALIZED ACROSS THE AREA TUESDAY
AFTERNOON AND EVENING SHOULD QUICKLY DEPART TO THE EAST/SOUTHEAST
TUESDAY NIGHT AS THE LOW LEVEL BAROCLINIC ZONE DOES THE SAME.
DECREASING LOW LEVEL MOISTURE SHOULD ALLOW FOR DECREASING
POTENTIAL INSTABILITY BUT WITH INCREASING OMEGA DUE TO THE
APPROACHING MID LEVEL SHORT WAVE...CHANCES FOR PRECIPITATION
CONTINUE IN THE FORECAST FOR MOST ALL OF OUR CWA TUESDAY NIGHT
INTO WEDNESDAY...AND LINGERING ACROSS OUR EAST/SOUTHEAST WEDNESDAY
NIGHT. DRY CONDITIONS ARE THEN FORECAST THURSDAY ONWARD.

A VERY WARM LOW LEVEL AIRMASS WILL CONTINUE TO PROMOTE AN
AFTERNOON HIGH TEMPERATURE IN THE 70S TO LOW 80S SUNDAY THROUGH
TUESDAY. THE PASSAGE OF THE LOW LEVEL BAROCLINIC ZONE ON TUESDAY
HOWEVER WILL THEN BRING AN END TO THE WARM WEATHER...WITH A COOLER
LOW LEVEL AIRMASS LIKELY PROMOTING AN AFTERNOON HIGH TEMPERATURE
IN THE 50S AND 60S TO FINISH OUT THE FORECAST PERIOD. AN OVERNIGHT
LOW TEMPERATURE IN THE 40S AND 50S IS EXPECTED SUNDAY NIGHT
THROUGH TUESDAY NIGHT...WITH LOWS RANGING FROM THE MID 30S TO THE
LOW 40S WEDNESDAY NIGHT ONWARD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1240 PM CDT FRI APR 26 2013

THE MAIN CONCERN FOR THIS TAF PERIOD WILL FOCUS ON WINDS AND
SLIGHT CHANCES FOR SHOWERS AND POSSIBLY A RUMBLE OF THUNDER OR TWO
LATE THIS AFTERNOON. NOTED OBSERVATIONS AND MODELS SUGGEST A SMALL
850 MB JET STREAK SHIFTING EASTWARD ACROSS THE PLAINS. THUS
LOCATIONS ROUGHLY FROM NORTH PLATTE TO LEXINGTON HAVE SEEN WIND
GUSTS NEAR 20 TO 25 KTS THIS AFTERNOON. ALTHOUGH...THIS AXIS
APPEARS TO BE SHIFTING EASTWARD MODELS SUGGEST THAT IT SHOULD
WEAKEN THROUGHOUT THE AFTERNOON. AS A RESULT...KEPT ANY MENTION OF
WIND GUST OUT OF TAF...BUT THE POSSIBILITY FOR A FEW GUSTS TO NEAR
OR AROUND 15 KT STILL LINGERS. MODELS ALSO CONTINUE TO HINT AT THE
POSSIBILITY FOR SCATTERED SCATTERED AT OR AROUND THE TERMINAL
LATER THIS AFTERNOON AND EVENING...MAINLY AFTER 0Z. INSTABILITY
PARAMETERS SUGGEST THAT A RUMBLE OF THUNDER OR TWO COULD BE
POSSIBLE. HOWEVER...WIDESPREAD SHOWERS ARE CERTAINLY NOT EXPECTED
AND CONFIDENCE IS LOW ENOUGH TO KEEP MENTION OUT OF TAF FOR NOW.


&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...SALTZMAN
LONG TERM...BRYANT
AVIATION...SALTZMAN





AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

 618 AM CDT FRI APR 26 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI APR 26 2013

A WEAK PACIFIC COLD FRONT WILL DROP THROUGH THE FCST AREA THIS
MORNING. THE H850 MB THERMAL RIDGE SHOULD REDEVELOP SOMEWHAT THIS
AFTERNOON. DEW POINTS IN THE 20S AND NEARLY FULL SUN SUPPORT MIXING
TO 700 MB AND HIGHS AROUND 70. WINDS SFC TO 700 MB REMAIN MOSTLY
NORTH AND WEAK AT 25 KTS OR LESS THROUGH TONIGHT WITH NEARLY NEUTRAL
THERMAL ADVECTION. GIVEN THE DRY AIR...LOWS IN THE 30S TO NEAR 40
ARE FCST TONIGHT. A WEAK LOW LEVEL JET DEVELOPS TONIGHT ACROSS THE
WEST LIMITING RADIATIONAL COOLING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI APR 26 2013

WARM WEATHER IS EXPECTED THROUGH THE WEEKEND...WITH A COUPLE OF WEAK
PACIFIC COLD FRONTAL PASSAGES. THESE WILL HAVE LITTLE AFFECT ON
TEMPERATURES...AND HIGHS IN THE 70S TO NEAR 80 DEGREES ARE
FORECASTED BOTH SATURDAY AND SUNDAY. MONDAY WILL CONTINUE TO BE
WARM...WITH SOUTHERLY WINDS DEVELOPING IN RESPONSE TO DEVELOPING SFC
LOW PRESSURE ACROSS WESTERN SOUTH DAKOTA.

BY TUESDAY...A LONG WAVE TROUGH WILL BEGIN TO DIG SOUTH FROM CANADA
INTO THE NORTHERN ROCKIES. THE 26/00Z RUN OF THE ECMWF LOOKS THE
BEST FOR US IN REGARDS TO PRECIPITATION. IT STALLS A FRONT/SFC
BOUNDARY TUESDAY ALONG THE NE/KS BORDER...WITH EASTERLY SFC WINDS
ADVECTING SOME LOW LEVEL MOISTURE WESTWARD INTO SOUTHWEST NEBRASKA
TO THE NORTH OF THE FRONT. TUESDAY NIGHT A STRONG SOUTHERLY LOW
LEVEL JET DEVELOPS ACROSS KS...WHILE A NORTHERN PLAINS JET STREAK
CROSSES THE DAKOTAS PLACING OUR AREA IN THE FAVORABLE RIGHT REAR
QUADRANT. THE COMBINATION OF A STRONG LOW LEVEL JET AND FAVORABLE
UPPER LEVEL JET DYNAMICS SHOULD SUPPORT AT LEAST SOME RISK OF
ELEVATED CONVECTION NORTH OF THE SFC BOUNDARY ACROSS MUCH OF
NEBRASKA. THE 26/00Z GFS INDICATES A SIMILAR SCENARIO...BUT STALLS
THE FRONT FARTHER SOUTH. THIS WOULD KEEP THE BETTER PRECIPITATION
CHANCES TO THE SOUTH AND EAST OF THE AREA. WILL CONTINUE TO MONITOR
THE MODEL TRENDS REGARDING THE FRONTAL PLACEMENT AND SUBSEQUENT
PRECIPITATION CHANCES. FOR NOW WILL CAP POPS AT 40 PERCENT UNTIL
MODELS COME INTO BETTER AGREEMENT.

BY MID TO LATE WEEK...THE 26/00Z RUN OF THE ECMWF HAS FINALLY LET GO
OF IT/S SOUTHWARD DEVELOPMENT OF THE LONG WAVE TROUGH INTO THE
CENTRAL CONUS. IT/S NOW MORE IN LINE WITH THE 26/00Z GFS AND GFS
ENSEMBLE MEAN...AND DIGS THE TROUGH INTO THE GREAT LAKES REGION
WHERE A CLOSED UPPER LOW DEVELOPS DUE TO A BLOCKY DOWNSTREAM UPPER
LEVEL RIDGE. CONFIDENCE HAS INCREASED SOMEWHAT IN THE FORECAST FOR
MID TO LATE NEXT WEEK DUE TO THE BETTER MODEL AGREEMENT. IT APPEARS
THAT MAINLY DRY AND COOL CONDITIONS WILL DEVELOP AFTER
WEDNESDAY...BUT NOT AS COLD AS THE TEMPERATURES WE HAVE EXPERIENCED
DURING THE PAST SEVERAL WEEKS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 614 AM CDT FRI APR 26 2013

VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. SCATTERED HIGH AND
MID LEVEL CLOUDINESS WILL CONTINUE.

&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT FRI APR 26 2013

VERY HIGH FIRE DANGER TODAY. 50 PERCENT OF THE RAP MODEL AND 50
PERCENT OF THE REST OF THE MODEL DATA PRODUCES RH AROUND 20 PERCENT
BUT WINDS ARE LIGHT GUSTING TO JUST 20 MPH.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
FIRE WEATHER...CDC







AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 339 AM CDT FRI APR 26 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI APR 26 2013

A WEAK PACIFIC COLD FRONT WILL DROP THROUGH THE FCST AREA THIS
MORNING. THE H850 MB THERMAL RIDGE SHOULD REDEVELOP SOMEWHAT THIS
AFTERNOON. DEW POINTS IN THE 20S AND NEARLY FULL SUN SUPPORT MIXING
TO 700 MB AND HIGHS AROUND 70. WINDS SFC TO 700 MB REMAIN MOSTLY
NORTH AND WEAK AT 25 KTS OR LESS THROUGH TONIGHT WITH NEARLY NEUTRAL
THERMAL ADVECTION. GIVEN THE DRY AIR...LOWS IN THE 30S TO NEAR 40
ARE FCST TONIGHT. A WEAK LOW LEVEL JET DEVELOPS TONIGHT ACROSS THE
WEST LIMITING RADIATIONAL COOLING.


.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI APR 26 2013

WARM WEATHER IS EXPECTED THROUGH THE WEEKEND...WITH A COUPLE OF WEAK
PACIFIC COLD FRONTAL PASSAGES. THESE WILL HAVE LITTLE AFFECT ON
TEMPERATURES...AND HIGHS IN THE 70S TO NEAR 80 DEGREES ARE
FORECASTED BOTH SATURDAY AND SUNDAY. MONDAY WILL CONTINUE TO BE
WARM...WITH SOUTHERLY WINDS DEVELOPING IN RESPONSE TO DEVELOPING SFC
LOW PRESSURE ACROSS WESTERN SOUTH DAKOTA.

BY TUESDAY...A LONG WAVE TROUGH WILL BEGIN TO DIG SOUTH FROM CANADA
INTO THE NORTHERN ROCKIES. THE 26/00Z RUN OF THE ECMWF LOOKS THE
BEST FOR US IN REGARDS TO PRECIPITATION. IT STALLS A FRONT/SFC
BOUNDARY TUESDAY ALONG THE NE/KS BORDER...WITH EASTERLY SFC WINDS
ADVECTING SOME LOW LEVEL MOISTURE WESTWARD INTO SOUTHWEST NEBRASKA
TO THE NORTH OF THE FRONT. TUESDAY NIGHT A STRONG SOUTHERLY LOW
LEVEL JET DEVELOPS ACROSS KS...WHILE A NORTHERN PLAINS JET STREAK
CROSSES THE DAKOTAS PLACING OUR AREA IN THE FAVORABLE RIGHT REAR
QUADRANT. THE COMBINATION OF A STRONG LOW LEVEL JET AND FAVORABLE
UPPER LEVEL JET DYNAMICS SHOULD SUPPORT AT LEAST SOME RISK OF
ELEVATED CONVECTION NORTH OF THE SFC BOUNDARY ACROSS MUCH OF
NEBRASKA. THE 26/00Z GFS INDICATES A SIMILAR SCENARIO...BUT STALLS
THE FRONT FARTHER SOUTH. THIS WOULD KEEP THE BETTER PRECIPITATION
CHANCES TO THE SOUTH AND EAST OF THE AREA. WILL CONTINUE TO MONITOR
THE MODEL TRENDS REGARDING THE FRONTAL PLACEMENT AND SUBSEQUENT
PRECIPITATION CHANCES. FOR NOW WILL CAP POPS AT 40 PERCENT UNTIL
MODELS COME INTO BETTER AGREEMENT.

BY MID TO LATE WEEK...THE 26/00Z RUN OF THE ECMWF HAS FINALLY LET GO
OF IT/S SOUTHWARD DEVELOPMENT OF THE LONG WAVE TROUGH INTO THE
CENTRAL CONUS. IT/S NOW MORE IN LINE WITH THE 26/00Z GFS AND GFS
ENSEMBLE MEAN...AND DIGS THE TROUGH INTO THE GREAT LAKES REGION
WHERE A CLOSED UPPER LOW DEVELOPS DUE TO A BLOCKY DOWNSTREAM UPPER
LEVEL RIDGE. CONFIDENCE HAS INCREASED SOMEWHAT IN THE FORECAST FOR
MID TO LATE NEXT WEEK DUE TO THE BETTER MODEL AGREEMENT. IT APPEARS
THAT MAINLY DRY AND COOL CONDITIONS WILL DEVELOP AFTER
WEDNESDAY...BUT NOT AS COLD AS THE TEMPERATURES WE HAVE EXPERIENCED
DURING THE PAST SEVERAL WEEKS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1230 AM CDT FRI APR 26 2013

WIND WILL CONTINUE TO DECREASE AND BECOME AT OR BELOW 10KT BEFORE
SHIFTING AROUND TO THE NORTH TO NORTHEAST. IT WILL THEN SWING
AROUND TO 020-040 BY 09Z BUT REMAIN LESS THAN 12KT. BY 15Z...THE
WIND WILL INCREASE TO 10-12 IN NORTHERN NEBRASKA AND 12-14G21-23KT
FROM 020-040 OVER CENTRAL AND SOUTHWEST NEBRASKA.

&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT FRI APR 26 2013

VERY HIGH FIRE DANGER TODAY. 50 PERCENT OF THE RAP MODEL AND 50
PERCENT OF THE REST OF THE MODEL DATA PRODUCES RH AROUND 20 PERCENT
BUT WINDS ARE LIGHT GUSTING TO JUST 20 MPH.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...SPRINGER
FIRE WEATHER...CDC





AREA FORECAST DISCUSSION

NWS RALEIGH NC

 845 PM EDT SAT APR 27 2013

.SYNOPSIS...
A SLOW MOVING STORM SYSTEM OVER THE MID MISSISSIPPI VALLEY WILL
APPROACH THE AREA LATE TONIGHT... AND WILL BRING UNSETTLED WEATHER
AS IT CROSSES THE MIDATLANTIC STATES AND CAROLINAS SUNDAY THROUGH
MONDAY.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 845 PM SATURDAY:

REST OF TONIGHT: THE DE FACTO THEME OF RECENT FORECASTS HAS BEEN TO
SLOW DOWN THE ARRIVAL OF RAIN... AS THIS INCOMING STORM SYSTEM HAS
BEEN PROGRESSING VERY SLOWLY EASTWARD... AND THE MODELS HAVE
CONTINUED TO STEADILY DELAYED PRECIP ARRIVAL FOR SEVERAL RUNS NOW.
THIS THEME MUST BE CONTINUED THIS EVENING... AS THE NEWEST
FINE-SCALE CONVECTION-ALLOWING MODEL RUNS GREATLY HOLD BACK THE
ARRIVAL OF SIGNIFICANT RAIN IN THE WESTERN CWA UNTIL CLOSE TO
DAYBREAK. ONE BROKEN BAND OF WEAKLY FORCED RAIN HAS STREAKED ACROSS
SWRN NC AND THE NC/SC BORDER IN THE LAST SEVERAL HOURS... SUPPORTED
IN PART BY SHEARING MID LEVEL VORTICITY. UPPER DIVERGENCE WILL
WEAKEN OVER NC AS A JET STREAK HEADS OFFSHORE WITH MID LEVEL RIDGING
BUILDING IN TONIGHT AHEAD OF THE INCOMING SLOW-MOVING SHORTWAVE
TROUGH OVER THE MID MISS VALLEY... LEADING TO DISSIPATION OF FORCED
ASCENT OVER NC. THE LOW LEVELS OVER THE WESTERN CWA HAVE MOISTENED
UP QUICKLY EARLY THIS EVENING BUT NOT SO IN THE NORTHEAST CWA... AND
THE RAP AND LOCAL WRF BRING THE SLIGHTLY DRIER AIR NOW OVER NE NC/SE
VA WESTWARD TONIGHT (DUE TO THE ESE SURFACE CIRCULATION AROUND THE
SURFACE HIGH CENTERED OFF DELMARVA)... A REASONABLE TRAJECTORY. WITH
THE WANING FORCING OVER NC... AND WITH THE STRONG SOUTHWESTERLY 850
MB JET THAT IS HELPING TO DRIVE THE CONVECTION OVER AL/N GA/E TN
EXPECTED TO HOLD WELL TO OUR WEST OVERNIGHT (ACCELERATING UP INTO
FAR WRN WV)... WE`RE UNLIKELY TO SEE ENOUGH OF A SURGE IN MOISTURE
OR INCREASE IN LIFT FOR ANYTHING BUT PATCHY VERY LIGHT RAIN OR
SPRINKLES UNTIL CLOSE TO SUNRISE. WILL LEAVE IN PATCHY SPRINKLES IN
THE WEST AND SOUTH FOR MUCH OF THE NIGHT... BUT WILL HOLD OFF THE
HIGHER POPS IN THE WESTERN CWA UNTIL AFTER 5 AM. THE OVERCAST MID
AND HIGH CLOUDS WILL HELP KEEP TEMPS UP OVERNIGHT... BUT ONLY SMALL
ADJUSTMENTS ARE NEEDED... LOWS NEAR 50 NORTHEAST TO MID 50S
SOUTHWEST. -GIH

THROUGH SUNDAY:
RAIN CHANCES WILL SLOWLY BUT STEADILY INCREASE FROM WEST TO EAST
THROUGH THE DAY ON SUNDAY AS THE BLOCKING RIDGE OVER THE EASTERN
SEABOARD SHIFTS OFFSHORE...ALLOWING THE UPPER TROUGH TO FINALLY
PROGRESS EASTWARD INTO THE APPALACHIANS. PWATS INCREASE TO 1.2-1.3"
LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT((2 STANDARD DEVIATIONS
ABOVE NORMAL)WITH THE EASTWARD PUSH OF SOUTHERLY 30KT LOW-LEVEL FEED
OF GULF MOISTURE INTO THE AREA. THUS...EXPECT CHANCES FOR RAIN TO
PRIMARILY BE CONFINED WEST OF HWY 1 THROUGH THE EARLY-MID AFTERNOON
BEFORE EVENTUALLY SPREADING EAST OF HWY 1 SUNDAY EVENING/NIGHT.

WIDESPREAD CLOUD COVER AND AREAL COVERAGE OF PRECIP WILL BE THE MAIN
DETERMINING FACTOR ON TEMPERATURES THROUGH THE PERIOD. OVERNIGHT LOWS
IN THE 50S EACH NIGHT. HIGHS SUNDAY...WILL BE VERY CAD
LIKE...ESPECIALLY IF RAINFALL THROUGH THE AFTERNOON IS CONFINED TO
WESTERN PORTIONS OF THE STATE. HIGHS IN THE LOWER 60S WEST TO LOWER
70S EAST.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 255 PM SATURDAY...

WIDESPREAD PRECIP WILL BE ONGOING TO START MONDAY MORNING. THIS
PRECIP WILL BE MAINLY CAUSED BY AN EASTWARD PROGRESSING UPPER
WAVE...ALTHOUGH SOME MODELS ARE ALSO HINTING AT A WEAK SURFACE WAVE
DEVELOPING...WHICH WOULD ALSO ENHANCE THE PRECIP. THE UPPER TROUGH
IS PROGGED TO BE ALMOST DIRECTLY OVERHEAD MONDAY AFTERNOON AND THEN
BE MOVING OFFSHORE BY MONDAY NIGHT. ANY RESIDUAL COOL STABLE CAD
LAYER SHOULD SCOUR OUT THROUGHOUT THE DAY ON MONDAY AS THE SURFACE
HIGH PROGRESSES FURTHER OFFSHORE AND SOUTHERLY FLOW TAKES OVER. AS A
RESULT...HAVE INCREASED TEMPS TO THE MID/UPPER 60S TO THE LOWER 70S.
IN ADDITION...WITH THE WARMER TEMPS AND THE FACT THAT THE UPPER
LEVEL TROUGH SHOULD BE RIGHT OVERHEAD DURING THE HEATING OF THE
DAY...THERE COULD BE SOME SCATTERED THUNDERSTORMS THAT DEVELOP
MONDAY AFTERNOON. AS THE UPPER LEVEL TROUGH AXIS SHIFTS EAST OF THE
REGION MONDAY NIGHT...DRIER AIR ALOFT WILL FILTER IN AND THE PRECIP
COVERAGE SHOULD DECREASE FROM WEST TO EAST MONDAY EVENING/NIGHT.
STORM TOTAL PRECIP (INCLUDING AMOUNTS THAT FALL BEFORE MONDAY) ARE
EXPECTED TO BE BETWEEN 1-2 INCHES. OVERNIGHT LOWS SHOULD GENERALLY
BE IN THE MID 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 255 PM SATURDAY...

STRENGTHENING SURFACE HIGH PRESSURE OVER NEW ENGLAND WILL BEGIN TO
BUILD DOWN INTO CENTRAL NC AND THEN LIKELY PERSIST THROUGH THE END
OF THE LONG TERM PERIOD. AS A RESULT...SURFACE WINDS SHOULD BE OUT
OF THE NORTHEAST FOR MUCH OF THE PERIOD AND THE AIR MASS SHOULD BE
RELATIVELY STABLE. IN ADDITION...MODELS NOW SHOW THE MID LEVEL RIDGE
GRADUALLY BUILDING DOWN TOWARDS THE MID ATLANTIC...WHICH HAD BEEN
FORECAST TO BE CENTERED OVER NORTHERN NEW ENGLAND. ALL OF THIS
SHOULD RESULT IN LESS IN THE WAY OF PRECIP COVERAGE...ESPECIALLY BY
THE MIDDLE TO END OF THE WORK WEEK WHEN IT VERY WELL COULD END UP
BEING MOSTLY DRY. TEMPS SHOULD GENERALLY BE IN THE LOW/MID 70S...
STILL SLIGHTLY BELOW NORMAL DUE TO THE COOL MOIST NORTHEASTERLY
FLOW. THERE IS STILL QUITE A BIT OF UNCERTAINTY WITH REGARDS TO OUR
NEXT SYSTEM...BUT THE BUILDING RIDGE OVER THE EAST COAST MAY HOLD IT
WEST OF THE REGION (WHILE A SOUTHERN STREAM SYSTEM IS SHUNTED TO OUR
SOUTH) UNTIL THE VERY END (OR JUST BEYOND) THE CURRENT FORECAST
PERIOD.

&&

.AVIATION /00Z SUNDAY THROUGH WEDNESDAY/...
AS OF 750 PM SATURDAY...

24-HR TAF PERIOD:
VFR CONDITIONS SHOULD CONTINUE THROUGH MIDNIGHT...ALTHOUGH A BRIEF
PERIOD OF MVFR VISBYS MAY BE POSSIBLE AT KFAY PRIOR TO 03Z AS LIGHT
RAIN MOVES ACROSS THE SOUTH. GENERALLY CONFIDENCE IS NOT TERRIBLY
HIGH WITH REGARD TO PRECIP ONSET...HOWEVER IT WILL BEGIN FIRST IN
THE WEST AND SLOWLY MOVE EAST THROUGHOUT THE DAY SUNDAY. THE LIGHT
RAIN/DRIZZLE OCCURRING ACROSS THE WEST AND SOUTH SHOULD DISSIPATE
OVER THE NEXT FEW HOURS. THE NEXT ROUND OF RAIN AT KINT AND KGSO
SHOULD MOVE IN AROUND 06Z SUNDAY AHEAD OF LOW PRESSURE SYSTEM
APPROACHING FROM THE WEST. WITH THE MAIN AREA OF RAIN...CIGS AND
VISBYS WILL LIKELY DROP INTO THE MVFR RANGE AND POSSIBLY IFR AT
TIMES. HAVE KEPT IFR CIGS OUT OF THIS ISSUANCE AS FORECAST SOUNDINGS
ARE BORDERLINE MVFR/IFR. IT IS POSSIBLE THE RAIN MAY MAKE IT INTO
KRDU AND KFAY BEFORE THE END OF THE TAF PERIOD...BUT CONFIDENCE IS
LOW AT THIS TIME SO HAVE LEFT THE RAIN AND ASSOCIATED LOW CIGS AND
VISBYS OUT AT KRDU...KFAY...AND KRWI FOR THE TIME BEING. WINDS
SHOULD REMAIN MAINLY LIGHT AND VARIABLE THROUGH SUNDAY MORNING...
BECOMING S/SE SUNDAY...INCREASING TO 5-10 KTS IN THE AFTERNOON. -KC

LOOKING AHEAD:
SUB-VFR CONDITIONS IN WIDESPREAD RAIN ARE EXPECTED AT ALL TERMINALS
SUNDAY NIGHT THROUGH MONDAY AFTERNOON AS THE AFOREMENTIONED UPPER
LEVEL DISTURBANCE PROGRESSES SLOWLY EAST ACROSS THE REGION.
CONDITIONS COULD BRIEFLY IMPROVE TO VFR MONDAY AFTERNOON/EVENING
AS THE UPPER TROUGH AND RAIN MOVE EAST OUT OF THE AREA. THEREAFTER
MORNING STRATUS/FOG WILL POSE A THREAT EACH DAY. -CBL

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...KC/CBL







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 133 AM EDT FRI APR 26 2013

.SYNOPSIS...
A DRYING TREND IS EXPECTED FRIDAY INTO SATURDAY AS HIGH PRESSURE
REACHES DOWN FROM THE NORTH. AS THIS HIGH PRESSURE SHIFTS OFF
SHORE AN AREA OF LOW PRESSURE WILL AFFECT THE SOUTHEAST PRODUCING
AN EXTENDED PERIOD OF UNSETTLED WEATHER THROUGH THE LATTER HALF
OF THE WEEKEND INTO EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 130 AM FRIDAY...BIGGEST CHANGE TO THE FORECAST IS TO INCLUDE
THE EXPANSIVE AREA OF LOW STRATUS THAT HAS BEEN MOVING STEADILY
WESTWARD ACROSS EASTERN SOUTH CAROLINA FOR THE PAST SEVERAL HOURS.
CLOUD CEILINGS ARE AS LOW AS 500-700 FT AGL...AND THIS MOISTURE
APPEARS TO BE ADVECTING WESTWARD ALONG THE LEADING EDGE OF AN
OTHERWISE SLIGHT INCREASE IN WINDS AT THE TOP OF THE BOUNDARY LAYER.
FORECAST SOUNDINGS FROM THE NAM AND RUC DO NOT SHOW ENOUGH WIND
SHEAR IN THE LOWEST 1000 FT TO PREVENT FOG DEVELOPMENT GIVEN THE
SMALL TEMPERATURE-DEWPOINT DEPRESSIONS NOTED VIRTUALLY ALL ACROSS
THE EASTERN CAROLINAS...SO I HAVE ADDED AREAS OF FOG TO THE FORECAST
FOR MAINLY INLAND AREAS. PREVIOUS DISCUSSION FROM 1030 PM FOLLOWS...

UPDATED FORECASTS AND GRIDS TO REMOVE ALL POPS AND PCPN OVER LAND
AREAS. THE BEST FORCING WILL PULL AWAY FROM THE FA...REMAINING OVER
THE OFFSHORE ATL WATERS. THE WARMER SSTS OF THE GULF STREAM WILL AID
PCPN DEVELOPMENT AND THE CONVECTION AS IT PUSHES FURTHER AWAY FROM
THE MAINLAND. SATELLITE IMAGERY TRENDS AND LATEST MODEL GUIDANCE
INDICATE CLOUDS TO DISSIPATE AND CLEAR SKIES TO OVERSPREAD THE FA
FROM THE W THRU NW. COULD OBSERVE LEFTOVER LOW LEVEL CONVECTIVE
DEBRIS CLOUDS ACROSS THE SOUTHERNMOST PORTIONS OF THE ILM CWA
THROUGH MIDNIGHT...BUT THESE TOO SHOULD SCOUR OUT DURING THE
PRE-DAWN FRIDAY HRS. HAVE SLIGHT MODIFIED/TWEAKED OVERNIGHT MINS AND
ESPECIALLY HOURLY DEWPOINTS TO ACCOUNT FOR THE EARLIER CONVECTION.
DO NOT ANTICIPATE FOG OVERNITE...SINCE THE NE-E DRY AIR SURGE WILL
ALSO KEEP ACTIVE MIXING IN THE LOW LEVELS. LOCATIONS WELL
INLAND...ALONG AND WEST OF THE I-95 CORRIDOR WILL HAVE THE BEST SHOT
TO SEE PATCHY FOG...BUT STILL JUST NOT ENOUGH TO ADVERTISE IN THE
CURRENT FORECASTS.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...HIGH PRESSURE EXTENDING DOWN FROM THE
GREAT LAKES ON FRIDAY WILL SHIFT EAST THROUGH SATURDAY REACHING
OFF THE MID ATLANTIC COAST BY EARLY SUN MORNING. IN THE UPPER
LEVELS A RIDGE TRIES TO BUILD UP FROM THE GULF COAST BUT A
SHORTWAVE WILL RIDE OVER THE TOP OF IT FROM THE CENTRAL STATES TO
THE OHIO VALLEY BY SUNDAY MORNING. OVERALL EXPECT FRIDAY TO REMAIN
DRY WITH A FEW HIGH CLOUDS MAKING IT INTO AREA BUT BY SATURDAY
INCREASING MID TO HIGH CLOUDS WILL REACH THE AREA FROM WEATHER
ASSOCIATED WITH SHORTWAVE AND ASSOCIATED SURFACE LOW TRACKING EAST
NORTHEAST. CLOUDS WILL CONTINUE TO INCREASE THROUGH LATE SATURDAY
INTO EARLY SUNDAY AS MID TO HIGH LEVEL FLOW INCREASES OUT OF THE
WEST NORTHWEST ADVECTING CLOUDS AND MOISTURE INTO AREA. BEST LIFT
AND MOISTURE WILL REMAIN TO THE WEST OF OUR LOCAL FORECAST AREA.
CAN NOT RULE OUT SOME PCP BUT OVERALL WILL KEEP LOW END POPS
LIMITED TO WESTERN ZONES LATE SAT AFTN AND INCREASING SLIGHTLY
THROUGH SAT NIGHT AS BEST SHORTWAVE ENERGY PASSES THROUGH.

A COOLER NORTHEAST TO EASTERLY FLOW WILL PERSIST THROUGH THE
PERIOD AS WINDS VEER AROUND AS THE HIGH SHIFTS EAST REMAINING
NORTH OF AREA. THE E-NE FLOW SHOULD HELP THE SEA BREEZE PENETRATE
INLAND FARTHER...ESPECIALLY ON SATURDAY WHEN WINDS ARE MORE
EASTERLY. TEMPS WILL WARM INTO THE 70S BUT MAY GET A COUPLE OF
DEGREES SHAVING OFF AS SEA BREEZE BRINGS COOLER OCEAN AIR INLAND
THROUGH THE AFTN AND CLOUDS INCREASE TO HELP FILTER OUT THE
SUN. OVERNIGHT LOWS WILL DROP JUST BELOW 50 INLAND AND LOWER 50S
ALONG THE COAST FRI NIGHT WITH FEWER CLOUDS AND LIGHTER WINDS
EXPECTED. BY SAT NIGHT...CLOUDS AND PCP WILL KEEP TEMPS IN THE 50S
MOST PLACES.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...SPLIT FLOW ALOFT EARLY IN THE PERIOD WILL
TRANSITION TO A BLOCKING PATTERN AS WEAK REX BLOCK SETS UP. HIGH
PRESSURE NORTH OF THE AREA WILL MAINTAIN NORTHEAST FLOW FOR MUCH OF
THE PERIOD KEEPING TEMPERATURES NEAR TO BELOW CLIMO.  LOW LEVEL
NORTHEAST TO EAST FLOW AND SOUTHERLY MID LEVEL FLOW WILL KEEP PLENTY
OF MOISTURE IN THE REGION. ALTHOUGH THERE ARE NO STRONGLY FORCED
FEATURES DIURNAL HEATING...DESPITE CONSIDERABLE CLOUD COVER...AND
DEVELOPING COASTAL TROUGH NEXT WEEK WILL HELP MAINTAIN SOME RAIN
CHANCES FOR MUCH OF THE PERIOD.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...EXPECT VFR TO PREVAIL THROUGH THE VALID PERIOD.

SLIGHTLY DRIER AIR IS ADVECTING IN AS HIGH PRESSURE FROM THE NORTH
BUILDS INTO OUR AREA. CLEAR SKIES EXIST ALONG THE COAST...BUT AN
EXPANSIVE AREA OF LOW STRATUS (BASES 500-1000 FT AGL) EXTENDING
ACROSS DARLINGTON...FLORENCE AND GEORGETOWN SC WILL PUSH SLOWLY WEST
INTO THE SC MIDLANDS OVER THE NEXT SEVERAL HOURS. AFTER DAYBREAK AND
THROUGH THE REMAINDER OF THE PERIOD...ANTICIPATE NEARLY CLEAR SKIES
WITH LIGHT NE WINDS...BECOMING MORE DIRECTLY ONSHORE DURING THE
AFTERNOON AT CRE/MYR WITH THE SEABREEZE.

EXTENDED OUTLOOK...VFR THROUGH SATURDAY AFTERNOON. UNSETTLED WEATHER
SATURDAY NIGHT THROUGH TUESDAY AS A STATIONARY COASTAL TROUGH GIVES
US MOSTLY CLOUDY CONDITIONS THROUGH TUESDAY WITH PERIODS OF RAIN
AND IFR CONDITIONS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM FRIDAY...MINIMAL SCA CONDITIONS REMAIN POSSIBLE OVER
THE NC WATERS LATER THIS MORNING. SEAS HAVE BUILT TO 5 FT AT THE
FRYING PAN SHOALS BUOY AND 4 FT AT THE NEARSHORE WRIGHTSVILLE BEACH
BUOY...AS THE NE WIND CONTINUES AT 15-20 KT. PREVIOUS DISCUSSION
FROM 1030 PM FOLLOWS...

BORDERLINE SCA HAS BEEN RAISED FOR THE ILM NC WATERS...WITH SCEC
CONTINUING FOR THE ILM SC WATERS. HAVE ALSO EXTENDED THE EXPIRATION
OF BOTH THE SCA AND SCEC TO 6 PM FRIDAY.

THE CURRENT NE-ENE SURGE HAS BEEN SLIGHTLY STRONGER THAN WHAT
EARLIER MODEL GUIDANCE HAD FORECAST/INDICATED. WITH A 1030+ SFC
HIGH RIDGING ACROSS THE FA FROM THE EASTERN GREAT LAKES AND THE
ASSOCIATED SFC PG SLIGHTLY TIGHTER THAN GUIDANCE PROGGED...HAVE
INCREASED THE NE-E WIND SPEEDS TO 15 TO 25 KT FOR THE ILM NC
WATERS...AND 15-20 KT WITH FEW GUSTS TO 25 KT FOR THE ILM SC
WATERS. THE BUILDING WIND DRIVEN WAVES FROM THE NE-E WIND SURGE
WILL INTERACT WITH THE 2 TO 3 FOOT EASTERLY SWELL AT 9 SECOND
PERIODS...TO ULTIMATELY PRODUCE 3 TO 6 FOOT SIGNIFICANT SEAS. THE 6
FOOTERS WILL OCCUR MAINLY OVER THE OUTER WATERS FROM SURF CITY TO
CAPE FEAR. THE EARLIER CONVECTION HAS MOVED EAST AND OFFSHORE THIS
EVENING AND DO NOT EXPECT ANY ADDITIONAL PCPN ACTIVITY.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...HIGH PRESSURE WILL RIDGE DOWN FROM THE NORTH
THROUGH THE PERIOD PRODUCING A MODEST NORTHEAST FLOW ON FRIDAY
VEERING AROUND TO THE EAST AND LIGHTENING THROUGH SATURDAY AS CAA
AND GRADIENT WEAKENS. WINDS WILL START OUT 15 TO 20 KTS OUT OF THE
NORTHEAST BUT WILL DIMINISH THROUGH SAT NIGH INTO SUNDAY DOWN TO
10 TO 15 KTS.

SEAS WILL BE LOWEST JUST SOUTH OF CAPE FEAR THROUGH BRUNSWICK
COUNTY HAVING BEST PROTECTION FROM NORTHEAST FLOW...RUNNING AROUND
1 TO 2 FT. SEAS IN THE OUTER WATERS WILL BE GREATEST...UP AROUND
5 FT THROUGH SAT MORNING INTO SAT AFTN AND MAY SEE SOME 6 FOOTERS
HEADING OUT TOWARD FRYING PAN SHOALS...WITH NORTHEAST WINDS UP
CLOSE TO 20 KTS.

A DECENT NORTHEASTERLY FLOW WILL BE IN PLACE
AT THE BEGINNING OF THE PERIOD ON THE ORDER OF 10-15 KNOTS WITH A
FEW PLACES ACROSS THE OUTER WATERS SEEING JUST OVER 15. AS COLD
AIR ADVECTION WANES SO WILL THE WINDS BUT HIGH PRESSURE TO THE
NORTHEAST WILL KEEP THIS FLOW IN PLACE WITH A SLIGHT DIURNAL
VEERING VIA THE SEA BREEZE. SWAN SEAS ARE JUST UNDER SMALL CRAFT
CRITERIA EARLY FRIDAY...3-5 FEET DROPPING TO 2-4 FEET BY SATURDAY.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...NORTHEAST TO EAST FLOW ACROSS THE WATERS SUN
WILL BECOME SOUTHEAST MON/TUE AS WEAK COASTAL TROUGH TAKES SHAPE.
WIND SPEEDS WILL BE 10 TO 15 KT FOR A MAJORITY OF THE PERIOD. SEAS
WILL RUN 2 TO 4 FT THROUGH THE PERIOD.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR AMZ250-252.

&&

$$

SYNOPSIS...RGZ
NEAR TERM...DCH/TRA
SHORT TERM...RGZ
LONG TERM...III
AVIATION...SGL/TRA






AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 1046 PM EDT SAT APR 27 2013

.SYNOPSIS...
AN INCREASINGLY MOIST WEDGE OF COOLER AIR WILL OVERSPREAD THE REGION
THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY
ALONG A STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE
COOL AIR WEDGE WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK. OUR
WEATHER PATTERN WILL LIKELY REMAIN UNSETTLED THROUGH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH SUNDAY/...
EVENING UPDATE...NO MAJOR CHANGES ARE NEEDED TO THE GOING FCST
OVERNIGHT. THE HI-RES MODELS HAVE HANDLED THE LULL IN PRECIP AS THE
H5 S/W ENERGY HAS BEEN MUTED TRAVERSING THE RIDGE AXIS. STILL LOOKS
GOOD FOR THE WARM FRONT ADVANCING TOWARD THE AREA DURING THE DAY
TOMORROW AND LLVL MOISTURE BEING MAINTAINED WHILE ISEN LIFT
INCREASES OVERNIGHT. THIS WILL SPAWN OFF MORE -SHRA ACROSS THE SRN
ZONES TO GO ALONG WITH THE WAVES OF ENERGY CROSSING THE NRN PART OF
THE CWFA. SO...NO CHANGES TO THE CAT POPS WILL BE MADE WITH THIS
UPDATE. DON/T ANTICIPATE ANY GOOD CHANCE THUNDER AS THE LLVL WEDGE
WILL REMAIN IN PLACE AND OVERALL BROAD SCALE SUBSIDENCE WILL HOLD
VERTICAL CELL DEVELOPMENT IN CHECK AS IS SEEN WITH THE FEW SHOWERS
ADVANCING FROM THE SW ATTM.

730 PM EDT UPDATE...THE PRECIP SHIELD IS STILL BEING WELL MAINTAINED
BY CHANNELED UPPER ENERGY AND ATL/GOM MOISTURE FLUX. THE 88D IS
SHOWING SHALLOW CELLS EMBEDDED WITHIN THE BAND AND NO REAL GOOD
CHANCE OF THUNDER WITH WARM MID LEVELS UNDERNEATH THE RIDGE. POPS
WERE ADJ UP ACROSS THE NRN ZONES WHERE THE BANDING HAS SET UP. A
DECREASE IN PRECIP COVERAGE WAS ADDED IN THE GRIDS OVER THE NEXT 3
HRS BASED ON THE HRRR AND HI/RES WRF INDICATING A N/LY LIFT AND SOME
LOSS OF ULVL SUPPORT. TEMPS WERE REDUCED A LITTLE TO ACCOUNT FOR THE
AREAS COOLER THAN FCST/D DUE TO LIGHT TO CONTINUED MODERATE PRECIP.

430 PM EDT UPDATE...BUMPED UP POPS ACROSS THE LOWER NC PIEDMONT AND
UPSTATE TO ACCOUNT FOR REGION OF LIGHT TO MODERATE RAIN ASSOCIATED
WITH TRAVERSING UPPER S/W. THE MELTING LAYER IS AROUND 6.5 KFT...SO
A BRIGHT BANDING IS INDICATED ON THE DUAL POL IN RELATION TO GRAUPEL
AND MELTING SNOW. DONT ANTICIPATE VERY TALL OR LONG LIVED CELLS IN
THIS ENVIRONMENT. HOURLY TEMPS HAVE BEEN ADJ DOWN A COUPLE DEGREES
MAINLY ACROSS THE UPSTATE AS THE THICK MULTI/LAYERED CLOUDS AND
PRECIP DRAG HAS KEPT THINGS COOLER THAN FCST/D.

AS OF 230 PM...SFC LOW PRESSURE WAS ANALYZED OVER THE ARKLATX AS
HIGH PRESSURE REMAINED CENTERED OVER THE NEW ENGLAND COAST. LATEST
WV IMAGES INDICATED THAT A MID LEVEL S/W WAS RIPPLING ALONG THE
KY/TN LINE. REGIONAL RADAR SHOWS A WIDE BAND OF SHOWERS AHEAD OF THE
WAVE...WEST ALONG A WARM FRONT ASSOCIATED WITH THE LOW.
OVERNIGHT...THE SFC LOW IS FORECAST TO TRACK NE...REACHING THE
SOUTHERN OHIO RIVER VALLEY BY 12Z SUN. THE SFC PATTERN BETWEEN THE
LOW AND RIDGING HIGH PRESSURE WILL PRODUCE STRENGTHENING SE LLVL
FLOW. IN ADDITION...A RIBBON OF JET DIVERGENCE WILL REMAIN ACROSS THE
SOUTHERN APPALACHIANS OVERNIGHT. THE COMBINATION OF DEEP
MOISTURE...UPSLOPE FLOW...AND UPPER SUPPORT SHOULD SUPPORT
WIDESPREAD SHOWERS ACROSS THE MTNS TONIGHT. AREAS EAST WILL CONTINUE
TO SEE ROUNDS OF SHRA...SUPPORTED MAINLY BY INCREASING 295K
ISENTROPIC LIFT. RAINFALL OVERNIGHT MAY RANGE FROM 0.75 TO AN
INCH...WITH PIEDMONT QPF RANGING FROM .3 TO .4 TO LESS ACROSS THE
ACROSS THE LAKELANDS. LOW TEMPERATURES WILL RANGE FROM THE U40S
ACROSS THE MTNS TO L50S EAST.

SUNDAY...LLVL ISENTROPIC LIFT WILL SUPPORT WIDESPREAD COVERAGE
THROUGH THE DAY. RAINFALL RATES MAY INCREASE DURING THE AFTERNOON AS
THE MID LEVEL TROF APPROACHES. IN ADDITION...NAM CAPES POOL ACROSS
THE NE GA...UPSTATE...AND SOUTHERN NC PIEDMONT TO 300-600 J/KG. DUE
TO THE INSTABILITY AND FORCING...I WILL INCREASE THE MENTION OF
TSRA. OVERALL...POPS WILL PEAK AROUND 100 PERCENT AT SOME POINT
DURING THE DAY. QPF ON SUNDAY RANGES A LITTLE OVER AN INCH ACROSS
THE SOUTHERN ESCARPMENT TO NEAR 0.75 EAST. HIGH TEMPERATURES WILL
FEATURE A CAD PATTERN WITH U50S ACROSS THE MTNS AND MID TO UP 60S
EAST.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 240 PM SAT...THE MAIN FORCING FROM THE LIFTING TROUGH AXIS
WILL MOVE THROUGH THE FORECAST AREA SUNDAY NIGHT IN THE FORM OF DEEP
LAYER DPVA...UPPER DIVERGENCE IN THE ENTRANCE REGION OF THE JETLET
STRETCHED UP THE APPALACHIANS...AND CONTINUED MOIST UPGLIDE IN S/SW
850 MB FLOW. THERE APPEARS TO BE SOME TREND TOWARD THE BEST FOCUS OF
OVERNIGHT QPF INTO THE PIEDMONT AND AWAY FROM THE MTNS. THIS MAKES
PINNING DOWN THE HYDRO THREAT AREA WITH ENOUGH CERTAINTY FOR A WATCH
MORE PROBLEMATIC AS THE 2.5 TO 3 INCH RAINFALL SWATH MAY NOW COVER A
GOOD CHUNK OF THE AREA. WILL CONTINUE TO FEATURE THE HEAVY RAIN
THREAT IN THE HWO AND NOW HIGHLIGHT ALL AREAS...INCLUDING CHARLOTTE
METRO.

THE AXIS OF THE UPPER TROUGH WILL CROSS THE REGION ON MONDAY...WITH
GRADUAL MID LEVEL DRYING BEHIND THE FEATURE. GIVEN THE ABUNDANT
LINGERING LOW LEVEL MOISTURE AND SLIGHTLY STEEPENING LAPSE RATES
UNDER THE PASSING TROUGH...THERE SHOULD BE ENOUGH INSTABILITY FOR
DECENT SCATTERED THUNDERSTORM COVERAGE THROUGH THE AFTN
HOURS...ESPECIALLY IN PIEDMONT SECTIONS.

UPPER RIDGING WILL DEVELOP MONDAY NIGHT THROUGH TUE NIGHT...BUT WITH
AN H5 WEAKNESS OVER THE LOWER MS RIVER VALLEY. LOW LEVEL MOISTURE
WILL PERSIST...WITH LOW CLOUDS AND FOG POSSIBLY REDEVELOPING BY
DAYBREAK TUE. HOWEVER...PROFILES APPEAR MUCH MORE CAPPED TO DEEP
CONVECTION BY TUE WITH LITTLE TO NO TRIGGERING UNDER THE SHALLOW
RIDGE. LOW LEVEL EASTERLY FLOW WILL GET REESTABLISHED LATE TUE
THROUGH TUE NIGHT. TEMPS WILL GRADUALLY WARM THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 220 PM SATURDAY...THE MEDIUM RANGE REMAINS UNSETTLED...AS
PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW LEVEL MOISTURE
INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES FOR SHOWERS AND
THUNDERSTORMS. INSTABILITY WILL BE BEST IN THIS PERIOD WEDNESDAY
AFTERNOON WITH CAPES ON THE OLD ECMWF 300 TO 500 BUT VERY LOW ON THE
MOST RECENT GFS. THAT IS THE DEPICTION ON THE GFS MODEL. THE ECMWF
IS SHOWING MUCH DRIER WEATHER FOR OUR IMMEDIATE REGION NEXT WEEKEND
AS IT HAS THE CLOSED OFF 500MB LOW OVER EASTERN KANSAS. THIS MODEL
SEEMS TO NOT BE AS RELIABLE GOING INTO THE SPRING. THE GFS ON THE
OTHER HAND HAS THE DEEP UPPER LOW OVER ARKANSAS FRIDAY AND ARRIVING
OVER HUNTSVILLE AL SUNDAY MORNING. IF THE GFS VERIFIES...DIURNAL
CONVECTION WEDNESDAY AND THURSDAY...INCREASING IN COVERAGE FRIDAY
AND SATURDAY AS A SURFACE LOW DEVELOPS LATE THURSDAY OVER LA AND
PULLS A WARM FRONT FROM AL TO THE CAROLINAS FRI AND SAT. AS THE WARM
FRONT PASSES ON SATURDAY...THE LOW LEVEL WIND FLOW WILL SWITCH
AROUND FROM EASTERLY TO WEST.  THE AREA NEAR THE WARM FRONT LOOKS TO
BE A GOOD ZONE OF LOW LEVEL CONVERGENCE AND THE 6 HOUR PRECIP ON THE
GFS INDICATES NEAR A THIRD TO A HALF INCH. AFTER SAYING
THIS...CONFIDENCE IN THE EVENTUAL OUTCOME A WEEK FROM NOW IS LOW AND
PREFER TO BE CONSERVATIVE WITH THE POP FORECAST KEEPING IT LOW IN
THE SLIGHT TO LOW CHANCE. TEMPERATURES WILL BE BELOW NORMAL FOR
HIGHS AND ABOVE NORMAL FOR LOWS EARLY IN PERIOD THEN DROPPING BELOW
NORMAL NEXT WEEKEND AS THE UPPER LOW COMES OVER OUR REGION.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
AT KCLT...A GENERALLY DETERIORATING TAF IS DEPICTED BEGINNING AROUND
07Z THROUGH THE PERIOD. NOT ENOUGH CONFIDENCE IS HAD TO INCLUDE THE
MOS IFR VSBYS IN SHRA DUE TO THE PREVIOUS ROUND OF SHOWERS AND VSBY
REMAINING IN THE MVFR RANGE. HOWEVER...WILL BRING CIGS DOWN TO LOW
MVFR AS THE WARM FRONT APPROACHES OVERNIGHT IN A HIGHLY MOIST ATMOS.
THE FRONT WILL PASS OVERHEAD AND BREAK DOWN THE WEDGE AROUND NOON
AND THIS WILL ENABLE A INSTABILITY GRADIENT TO FORM OVER OR NEAR THE
AIRFIELD. THUS A PROB30 TS WILL BE ADDED AT 21Z THROUGH 00Z.

ELSEWHERE...EXPECT CIGS TO GO BACK AND FORTH BTW RESTRICTED AND VFR
AS THE BAND OF PRECIP ALIGNED WITH A H5 S/W GRADUALLY WEAKENS AND
LIFTS NORTH THROUGH 06Z. VSBYS SHOULD GENERALLY IMPROVE THROUGH THIS
TIME. AN ADVANCING WARM FRONT WILL BRING ANOTHER ROUND OF -SHRA
OVERNIGHT AND THROUGH THE MORNING HRS. CIGS ARE EXPECTED TO FALL
INTO THE MVFR RANGE AND POSSIBLY IFR THROUGH MID DAY. SOME STRONGER
EMBEDDED SHOWERS AND TS WILL DEVELOP IN THE AFTERNOON AND THIS WILL
HELP KEEP CIGS/VSBYS MVFR/IFR THROUGH THE PERIOD.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            02-08Z        08-14Z        14-20Z        20-02Z
KCLT       HIGH  85%     MED   79%     HIGH  97%     HIGH 100%
KGSP       HIGH  86%     HIGH  84%     HIGH  90%     HIGH  96%
KAVL       MED   63%     HIGH  87%     HIGH  87%     HIGH  96%
KHKY       HIGH  80%     MED   72%     HIGH  87%     HIGH  94%
KGMU       MED   79%     HIGH  86%     MED   79%     HIGH  98%
KAND       HIGH  84%     HIGH  88%     HIGH  90%     HIGH  86%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...DEO
NEAR TERM...NED/SBK
SHORT TERM...HG
LONG TERM...DEO
AVIATION...SBK







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 804 PM EDT SAT APR 27 2013

.SYNOPSIS...
AN INCREASINGLY MOIST WEDGE OF COOLER AIR WILL OVERSPREAD THE REGION
THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY
ALONG A STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE
COOL AIR WEDGE WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK. OUR
WEATHER PATTERN WILL LIKELY REMAIN UNSETTLED THROUGH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH SUNDAY/...
730 PM EDT UPDATE...THE PRECIP SHIELD IS STILL BEING WELL MAINTAINED
BY CHANNELED UPPER ENERGY AND ATL/GOM MOISTURE FLUX. THE 88D IS
SHOWING SHALLOW CELLS EMBEDDED WITHIN THE BAND AND NO REAL GOOD
CHANCE OF THUNDER WITH WARM MID LEVELS UNDERNEATH THE RIDGE. POPS
WERE ADJ UP ACROSS THE NRN ZONES WHERE THE BANDING HAS SET UP. A
DECREASE IN PRECIP COVERAGE WAS ADDED IN THE GRIDS OVER THE NEXT 3
HRS BASED ON THE HRRR AND HI/RES WRF INDICATING A N/LY LIFT AND SOME
LOSS OF ULVL SUPPORT. TEMPS WERE REDUCED A LITTLE TO ACCOUNT FOR THE
AREAS COOLER THAN FCST/D DUE TO LIGHT TO CONTINUED MODERATE PRECIP.

430 PM EDT UPDATE...BUMPED UP POPS ACROSS THE LOWER NC PIEDMONT AND
UPSTATE TO ACCOUNT FOR REGION OF LIGHT TO MODERATE RAIN ASSOCIATED
WITH TRAVERSING UPPER S/W. THE MELTING LAYER IS AROUND 6.5 KFT...SO
A BRIGHT BANDING IS INDICATED ON THE DUAL POL IN RELATION TO GRAUPEL
AND MELTING SNOW. DONT ANTICIPATE VERY TALL OR LONG LIVED CELLS IN
THIS ENVIRONMENT. HOURLY TEMPS HAVE BEEN ADJ DOWN A COUPLE DEGREES
MAINLY ACROSS THE UPSTATE AS THE THICK MULTI/LAYERED CLOUDS AND
PRECIP DRAG HAS KEPT THINGS COOLER THAN FCST/D.

AS OF 230 PM...SFC LOW PRESSURE WAS ANALYZED OVER THE ARKLATX AS
HIGH PRESSURE REMAINED CENTERED OVER THE NEW ENGLAND COAST. LATEST
WV IMAGES INDICATED THAT A MID LEVEL S/W WAS RIPPLING ALONG THE
KY/TN LINE. REGIONAL RADAR SHOWS A WIDE BAND OF SHOWERS AHEAD OF THE
WAVE...WEST ALONG A WARM FRONT ASSOCIATED WITH THE LOW.
OVERNIGHT...THE SFC LOW IS FORECAST TO TRACK NE...REACHING THE
SOUTHERN OHIO RIVER VALLEY BY 12Z SUN. THE SFC PATTERN BETWEEN THE
LOW AND RIDGING HIGH PRESSURE WILL PRODUCE STRENGTHENING SE LLVL
FLOW. IN ADDITION...A RIBBON OF JET DIVERGENCE WILL REMAIN ACROSS THE
SOUTHERN APPALACHIANS OVERNIGHT. THE COMBINATION OF DEEP
MOISTURE...UPSLOPE FLOW...AND UPPER SUPPORT SHOULD SUPPORT
WIDESPREAD SHOWERS ACROSS THE MTNS TONIGHT. AREAS EAST WILL CONTINUE
TO SEE ROUNDS OF SHRA...SUPPORTED MAINLY BY INCREASING 295K
ISENTROPIC LIFT. RAINFALL OVERNIGHT MAY RANGE FROM 0.75 TO AN
INCH...WITH PIEDMONT QPF RANGING FROM .3 TO .4 TO LESS ACROSS THE
ACROSS THE LAKELANDS. LOW TEMPERATURES WILL RANGE FROM THE U40S
ACROSS THE MTNS TO L50S EAST.

SUNDAY...LLVL ISENTROPIC LIFT WILL SUPPORT WIDESPREAD COVERAGE
THROUGH THE DAY. RAINFALL RATES MAY INCREASE DURING THE AFTERNOON AS
THE MID LEVEL TROF APPROACHES. IN ADDITION...NAM CAPES POOL ACROSS
THE NE GA...UPSTATE...AND SOUTHERN NC PIEDMONT TO 300-600 J/KG. DUE
TO THE INSTABILITY AND FORCING...I WILL INCREASE THE MENTION OF
TSRA. OVERALL...POPS WILL PEAK AROUND 100 PERCENT AT SOME POINT
DURING THE DAY. QPF ON SUNDAY RANGES A LITTLE OVER AN INCH ACROSS
THE SOUTHERN ESCARPMENT TO NEAR 0.75 EAST. HIGH TEMPERATURES WILL
FEATURE A CAD PATTERN WITH U50S ACROSS THE MTNS AND MID TO UP 60S
EAST.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 240 PM SAT...THE MAIN FORCING FROM THE LIFTING TROUGH AXIS
WILL MOVE THROUGH THE FORECAST AREA SUNDAY NIGHT IN THE FORM OF DEEP
LAYER DPVA...UPPER DIVERGENCE IN THE ENTRANCE REGION OF THE JETLET
STRETCHED UP THE APPALACHIANS...AND CONTINUED MOIST UPGLIDE IN S/SW
850 MB FLOW. THERE APPEARS TO BE SOME TREND TOWARD THE BEST FOCUS OF
OVERNIGHT QPF INTO THE PIEDMONT AND AWAY FROM THE MTNS. THIS MAKES
PINNING DOWN THE HYDRO THREAT AREA WITH ENOUGH CERTAINTY FOR A WATCH
MORE PROBLEMATIC AS THE 2.5 TO 3 INCH RAINFALL SWATH MAY NOW COVER A
GOOD CHUNK OF THE AREA. WILL CONTINUE TO FEATURE THE HEAVY RAIN
THREAT IN THE HWO AND NOW HIGHLIGHT ALL AREAS...INCLUDING CHARLOTTE
METRO.

THE AXIS OF THE UPPER TROUGH WILL CROSS THE REGION ON MONDAY...WITH
GRADUAL MID LEVEL DRYING BEHIND THE FEATURE. GIVEN THE ABUNDANT
LINGERING LOW LEVEL MOISTURE AND SLIGHTLY STEEPENING LAPSE RATES
UNDER THE PASSING TROUGH...THERE SHOULD BE ENOUGH INSTABILITY FOR
DECENT SCATTERED THUNDERSTORM COVERAGE THROUGH THE AFTN
HOURS...ESPECIALLY IN PIEDMONT SECTIONS.

UPPER RIDGING WILL DEVELOP MONDAY NIGHT THROUGH TUE NIGHT...BUT WITH
AN H5 WEAKNESS OVER THE LOWER MS RIVER VALLEY. LOW LEVEL MOISTURE
WILL PERSIST...WITH LOW CLOUDS AND FOG POSSIBLY REDEVELOPING BY
DAYBREAK TUE. HOWEVER...PROFILES APPEAR MUCH MORE CAPPED TO DEEP
CONVECTION BY TUE WITH LITTLE TO NO TRIGGERING UNDER THE SHALLOW
RIDGE. LOW LEVEL EASTERLY FLOW WILL GET REESTABLISHED LATE TUE
THROUGH TUE NIGHT. TEMPS WILL GRADUALLY WARM THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 220 PM SATURDAY...THE MEDIUM RANGE REMAINS UNSETTLED...AS
PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW LEVEL MOISTURE
INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES FOR SHOWERS AND
THUNDERSTORMS. INSTABILITY WILL BE BEST IN THIS PERIOD WEDNESDAY
AFTERNOON WITH CAPES ON THE OLD ECMWF 300 TO 500 BUT VERY LOW ON THE
MOST RECENT GFS. THAT IS THE DEPICTION ON THE GFS MODEL. THE ECMWF
IS SHOWING MUCH DRIER WEATHER FOR OUR IMMEDIATE REGION NEXT WEEKEND
AS IT HAS THE CLOSED OFF 500MB LOW OVER EASTERN KANSAS. THIS MODEL
SEEMS TO NOT BE AS RELIABLE GOING INTO THE SPRING. THE GFS ON THE
OTHER HAND HAS THE DEEP UPPER LOW OVER ARKANSAS FRIDAY AND ARRIVING
OVER HUNTSVILLE AL SUNDAY MORNING. IF THE GFS VERIFIES...DIURNAL
CONVECTION WEDNESDAY AND THURSDAY...INCREASING IN COVERAGE FRIDAY
AND SATURDAY AS A SURFACE LOW DEVELOPS LATE THURSDAY OVER LA AND
PULLS A WARM FRONT FROM AL TO THE CAROLINAS FRI AND SAT. AS THE WARM
FRONT PASSES ON SATURDAY...THE LOW LEVEL WIND FLOW WILL SWITCH
AROUND FROM EASTERLY TO WEST.  THE AREA NEAR THE WARM FRONT LOOKS TO
BE A GOOD ZONE OF LOW LEVEL CONVERGENCE AND THE 6 HOUR PRECIP ON THE
GFS INDICATES NEAR A THIRD TO A HALF INCH. AFTER SAYING
THIS...CONFIDENCE IN THE EVENTUAL OUTCOME A WEEK FROM NOW IS LOW AND
PREFER TO BE CONSERVATIVE WITH THE POP FORECAST KEEPING IT LOW IN
THE SLIGHT TO LOW CHANCE. TEMPERATURES WILL BE BELOW NORMAL FOR
HIGHS AND ABOVE NORMAL FOR LOWS EARLY IN PERIOD THEN DROPPING BELOW
NORMAL NEXT WEEKEND AS THE UPPER LOW COMES OVER OUR REGION.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT...A GENERALLY DETERIORATING TAF IS DEPICTED BEGINNING AROUND
07Z THROUGH THE PERIOD. NOT ENOUGH CONFIDENCE IS HAD TO INCLUDE THE
MOS IFR VSBYS IN SHRA DUE TO THE PREVIOUS ROUND OF SHOWERS AND VSBY
REMAINING IN THE MVFR RANGE. HOWEVER...WILL BRING CIGS DOWN TO LOW
MVFR AS THE WARM FRONT APPROACHES OVERNIGHT IN A HIGHLY MOIST ATMOS.
THE FRONT WILL PASS OVERHEAD AND BREAK DOWN THE WEDGE AROUND NOON
AND THIS WILL ENABLE A INSTABILITY GRADIENT TO FORM OVER OR NEAR THE
AIRFIELD. THUS A PROB30 TS WILL BE ADDED AT 21Z THROUGH 00Z.

ELSEWHERE...EXPECT CIGS TO GO BACK AND FORTH BTW RESTRICTED AND VFR
AS THE BAND OF PRECIP ALIGNED WITH A H5 S/W GRADUALLY WEAKENS AND
LIFTS NORTH THROUGH 06Z. VSBYS SHOULD GENERALLY IMPROVE THROUGH THIS
TIME. AN ADVANCING WARM FRONT WILL BRING ANOTHER ROUND OF -SHRA
OVERNIGHT AND THROUGH THE MORNING HRS. CIGS ARE EXPECTED TO FALL
INTO THE MVFR RANGE AND POSSIBLY IFR THROUGH MID DAY. SOME STRONGER
EMBEDDED SHOWERS AND TS WILL DEVELOP IN THE AFTERNOON AND THIS WILL
HELP KEEP CIGS/VSBYS MVFR/IFR THROUGH THE PERIOD.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH  81%     MED   62%     HIGH  86%     HIGH 100%
KGSP       HIGH  85%     MED   76%     HIGH  87%     HIGH  92%
KAVL       MED   62%     MED   75%     HIGH  93%     HIGH  94%
KHKY       MED   73%     MED   73%     HIGH  81%     HIGH  93%
KGMU       HIGH  80%     HIGH  80%     MED   69%     HIGH  92%
KAND       MED   78%     MED   76%     HIGH  87%     HIGH  83%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...DEO
NEAR TERM...NED/SBK
SHORT TERM...HG
LONG TERM...DEO
AVIATION...SBK







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 441 PM EDT FRI APR 26 2013

.SYNOPSIS...
AN INCREASINGLY MOIST WEDGE OF COOLER AIR WILL OVERSPREAD THE REGION
THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY
ALONG A STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE
COOL AIR WEDGE WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
430 PM UPDATE...FCST IS IN GOOD SHAPE. MADE MINOR TWEAKS TO TEMPS
AND TD/S. CLOUD COVER WAS ADJ INCORPORATING THE LATEST VIS
INDICATING BKN/OVC ACU/CI OVER THE WRN NC MTNS. WINDS WERE BUMPED UP
A LITTLE OVER THE MTNS AND BLENDED WITH THE 20Z RAP GUIDANCE.

AS OF 230 PM...LATEST SATELLITE IMAGES AND VIEW OUT OF THE WINDOW
INDICATE THAT THIN CIRRUS HAS STARTED TO SWEEP ACROSS THE FORECAST
AREA...ARRIVING FROM THE WEST. WITH THE ARRIVAL OF THE HIGH
CLOUDS...TEMPERATURES ACROSS THE REGION WILL LIKELY PEAK OVER THE
NEXT HOUR...ESPECIALLY ACROSS THE FOOTHILL AREAS. OVERNIGHT...1030MB
HIGH WILL BECOME CENTERED OVER NEW ENGLAND...RIDGING SW ACROSS THE
CWA. TO THE WEST...LOW PRESSURE IS EXPECTED TO TRACK NE...REACHING
THE ARKLATX BY 12Z SAT. THE ASSOCIATED WARM FRONT WILL LIKELY RUN
ACROSS TN INTO WESTERN NC BY DAYBREAK SAT. SHORT RANGE MODELS
INDICATE THAT A MID LEVEL S/W WILL RIPPLE ACROSS THE MID MISSISSIPPI
RIVER VALLEY THIS EVENING...REACHING KY/TN LATE TONIGHT. THE
COMBINATION OF THE MID LEVEL FORCING...WARM FRONT...AND INCREASING
MOISTURE SHOULD SUPPORT AN EXPANDING AREA OF RAIN WEST OF THE
SOUTHERN APPALACHIANS OVERNIGHT. A BAND OF SHRA IS EXPECTED TO
DEVELOP NORTH OF THE SFC WARM FRONT LATE TONIGHT...SLIDING ACROSS
THE WESTERN AND CENTRAL MOUNTAINS AND NRN SC UPSTATE DURING AROUND
SUNRISE. I WILL INCREASE POPS TO CHC TO LIKELY ACROSS THE NC MTNS
AND ADJACENT FOOTHILLS BY 12Z SAT.

ON SATURDAY...THE CENTER OF THE LOW PRESSURE IS FORECAST TO TRACK
ACROSS THE MID MISSISSIPPI RIVER VALLEY BY 0Z SUN. AS THE LOW TRACKS
NE...THE ASSOCIATED WARM FRONT WILL LIFT NORTH...PIVOTING ACROSS THE
WESTERN NC MTNS DURING THE DAY. I WILL FAVOR THE MTNS AND FOOTHILLS
FOR CATE AND LIKELY POPS. COVERAGE SHOULD PUSH EAST DURING THE MID
AND LATE AFTERNOON ACROSS THE I-77 CORRIDOR. QPF RANGES FROM NEAR
THREE-QUARTERS OF AN INCH ACROSS THE WESTERN NC MTNS TO LESS THAN A
TENTH OF AN INCH EAST OF I-77. BASED ON THE TIMING OF THE PRECIP...I
WILL KEEP HIGH TEMPS LIMITED ACROSS THE MTNS TO THE 50S...POSSIBLY
REACHING THE U60S ACROSS THE EASTERN PIEDMONT.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 230 PM FRI...THE UPSTREAM H5 LOW CENTER WILL SLOWLY OPEN UP
AND LIFT NE ACROSS IL/IN SAT NIGHT THROUGH SUNDAY. MODEL TIME
HEIGHTS AHEAD OF THIS FEATURE SHOW DEEP MOISTURE ARRIVING OVER THE
AREA...WITH UPPER DIVERGENCE DEVELOPING S OF A JETLET THROUGH THE
MID ATLANTIC AREA...AS WELL AS IMPROVING SRLY UPSLOPE FLOW INTO THE
MTNS AND UPGLIDE OVER AN IN SITU SFC CAD LAYER. THE CAD WILL ONLY
GRADUALLY SHALLOW OUT THROUGH SUNDAY GIVEN THE DEEP LAYER SRLY FLOW.
ANY INSTABILITY SUNDAY AFTN SHOULD BE CONFINED TO MAINLY THE SRN
PIEDMONT. THE BEST LOW LEVEL UPGLIDE WILL BE CENTERED OVER THE
FORECAST AREA MIDDAY SUNDAY...WITH A SECONDARY SURGE OF
MOISTURE/FORCING SUNDAY NIGHT AS A COLD FRONT APPROACHES FROM THE W.
QPF WILL BE THE MAIN FORECAST ISSUE DURING THIS PERIOD...WITH THE
SRLY UPSLOPE FLOW LIKELY PRODUCING A LOCAL MAXIMA ALONG S/SE UPSLOPE
PRONE AREAS OF THE SRN APPALACHIANS. THE GFS QPF IS A HIGH END
OUTLIER WITH STORM TOTALS OF 4 TO 5 INCHES IN THE SRN NC MTNS...DUE
MAINLY TO A WAVE RIDING UP THE SRN APPALACHIANS SUNDAY NIGHT. THE
OTHER MODELS/ENSEMBLES FEATURE A CONSENSUS MORE IN THE 3.0 TO 3.5
RANGE IN SRLY UPSLOPE AREAS...IN GOOD AGREEMENT WITH WPC.
PRECIPITABLE WATER ANOMALIES ARE FORECAST TO BE 1 TO 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND ANTECEDENT CONDITIONS ARE FAIRLY DRY.
ALL THINGS CONSIDERED...WILL FEATURE AN HWO MENTION OF ISOLATED
HYDRO PROBLEMS LATE THIS WEEKEND.

DEEPER MOISTURE WILL GRADUALLY DIMINISH FROM THE WEST ON MONDAY AS
THE UPPER SUPPORT LIFTS AWAY NORTH OF THE AREA...BUT THERE WILL BE
PLENTY OF LINGERING SFC TO 850 MB MOISTURE AS THE FRONT WASHES OUT
AND THE LOW LEVEL FLOW VEERS MORE SOUTHWESTERLY. TEMPS WILL REMAIN
COOL OVER THE NW NC PIEDMONT MONDAY...BUT WITH GREATER INSTABILITY
DEVELOPING BACK TO THE SW. WILL FEATURE SHOTGUN CHANCE POPS ON
MAINLY A DIURNAL SCHEDULE FOR SHOWERS AND THUNDERSTORMS
MONDAY...WANING TO SCHC MONDAY NIGHT.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 110 PM FRIDAY...WILL CONTINUE TO GIVE PROPS TO THE 26/00 UTC OP
ECMWF WHICH LINGERS UPPER LEVEL WEAKNESS ATOP THE CWFA THROUGH
TUESDAY. BASED ON THIS...INHERITED SHOTGUN CHANCE POP WILL REMAIN
WITH MAX TEMPS CLOSE TO THE LATE APRIL CLIMO. THE LATEST MEDIUM
RANGE MODEL MASS FIELDS AND ASSOCIATED RESPONSE ARE NOT TOO TERRIBLY
DIFFERENT FOR WEDNESDAY...PROGGING AN INCREASE IN ATLANTIC FETCH
AROUND NEW ENGLAND HIPRES...LEADING TO ONGOING DECENT PCPN CHANCES.

AN INCREASINGLY TRICKY FCST LOOKS TO BE SHAPING UP FOR LATE WEEK AS
DIGGING MID-CONUS L/WV TROUGH SHOULD NUDGE POTENTIALLY WAVY
BAROCLINIC ZONE INTO THE SOUTHERN APPALACHIANS WHILE SOUTHERN STREAM
ENERGY IS PROGGED TO SPIN UP GULF LOW PRESSURE. ON THE 26/00 UTC
ECMWF...THE CWFA IS POSITIONED BETWEEN THE MAIN RESPONSE AREAS OF
THESE TWO FEATURES...WHILE THE NEW 26/12 UTC OP GFS HAS US WELL
WITHIN THE DEEP FORCING AND MOISTURE. AT THIS POINT...THE BEST
COURSE OF ACTION IS TO STICK CLOSE TO THE WPC FCST OF A SOLID
MID CHANCE POP AND SLIGHTLY BELOW NORMAL MAX TEMPERATURES. GIVEN
THE MODEL DIFFERENCES WITH RESPECT TO JUST HOW THE DYNAMIC PATTERN
WILL EVOLVE BY NEXT FRIDAY...FCST CONFIDENCE IS BELOW NORMAL AND
PLAN ON SIMPLY GOING WITH THE WPC FCST OF SOLID MID-CHANCE POP
AND COOLER THAN PERSISTENCE.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...HIGH CONFIDENCE VFR FORECAST THROUGH THE TAF PERIOD.
CONDITIONS WILL BEGIN CLEAR...WITH CIRRUS ARRIVING FROM THE WEST BY
LATE AFTERNOON. HIGH PRESSURE CENTERED OVER NEW ENGLAND WILL RIDGE
SW ACROSS THE WESTERN CAROLINAS OVERNIGHT. NEAR TERM MODEL INDICATED
THAT A WARM FRONT WILL DEVELOP ACROSS TN/W NC BY 12Z SAT. THE
FRONT WILL PRESS NORTHWARD THROUGH THE DAY...BUT REMAINING SOUTH OF
THE TERMINAL BEFORE 18Z. FORECAST SOUNDINGS INDICATE THAT MOISTURE
SHOULD INCREASE FROM THE TOP DOWN...WITH BKN060 EXPECTED DURING THE
FINAL HOURS OF THE TAF. WINDS SHOULD BECOME LIGHT FROM THE SSW
TONIGHT AND SAT.

ELSEWHERE...WESTERN CAROLINA TERMINALS WILL REMAIN VFR THROUGH THIS
EVENING. SKC EARLY THIS AFTERNOON WILL BECOME FEW TO SCT WITH CIRRUS
BY LATE THIS AFTERNOON. FORECAST SOUNDINGS INDICATE THAT MOISTURE
WILL INCREASE FROM THE TOP DOWN AS A WARM FRONT APPROACHES LATE
TONIGHT. KAVL SHOULD SEE CLOUD BASES LOWER TO MVFR AROUND
SUNRISE...REMAINING MVFR THROUGH THE REMAINDER OF THE TAF PERIOD.
BEGINNING AROUND 12Z SAT...A WARM FRONT WILL REACH TN/W NC AS A MID
LEVEL DISTURBANCE RIPPLES EASTWARD OVER H5 RIDGING. THE COMBINATION
OF LOW AND MID FORCING SHOULD SUPPORT AN EXPANDING AREA OF SHRA
ACROSS THE REGION SAT MORNING. KAVL WILL SEE THE GREATEST CHC...WITH
LIKELY POPS AFTER 15Z SAT. WINDS SHOULD BECOME LIGHT FROM THE SSW
TONIGHT AND SAT.

OUTLOOK...A WEDGE OF COLD AIR THAT WILL AFFECT THE REGION SUNDAY AND
MONDAY...ALONG WITH THE POSSIBILITY OF PERIODIC RESTRICTIONS.

CONFIDENCE TABLE...

            20-02Z        02-08Z        08-14Z        14-20Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH  92%     MED   74%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...CSH
NEAR TERM...NED/SBK
SHORT TERM...HG
LONG TERM...CSH
AVIATION...NED







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 438 AM EDT FRI APR 26 2013

.SYNOPSIS...
A DRY RIDGE OF HIGH PRESSURE WILL GIVE WAY TO A WEDGE OF MOIST AND
COOL AIR OVER THE WEEKEND. WEAK LOW PRESSURE WILL MOVE ACROSS THE
TENNESSEE VALLEY ALONG A STALLED COLD FRONT OVER THE WEEKEND. THE
FRONT WILL SLOWLY DISSIPATE AND THE COOL AIR WEDGE WILL GRADUALLY
WEAKEN INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
415 AM UPDATE...RE-EVALUATED FROST/FREEZE POTENTIAL FOR THIS
MORNING. ASOS/AWOS NETWORK SUGGESTS LITTLE RISK OF FREEZE EXCEPT IN
THE LITTLE TENN RIVER VALLEY PER LAST FEW FRANKLIN OBS. MESONET
SITES HOWEVER REVEAL MANY SITES IN THE FREEZE WARNING AREA SITTING
AT 34-35F AND THINK THERE IS STILL A DECENT CHANCE THEY WILL AT
LEAST BRIEFLY FREEZE...WITH A COUPLE MORE HOURS OF CALM NIGHTTIME
CONDITIONS TO GO. AS FOR FROST ADVY AREA IT IS LOOKING LIKE THE
FROST WILL REMAIN PATCHY WITH MANY SITES STILL REPORTING 40S.
HOWEVER RADIATION AND CALM CONDITIONS COULD MEAN SURFACES DIP WELL
BELOW AIR TEMPS AND I WOULD PREFER TO ERR ON THE SIDE OF CAUTION AND
MAINTAIN THE ADVY THIS LATE IN THE GAME. DID REVISE TEMP/DEWPT
TRENDS THRU DAYBREAK USING LATEST OBS.

AS OF 3 AM FRI...UPPER S/W TROUGH WILL CONTINUE TO ADVECT TOWARD THE
ATLANTIC THIS MORNING WITH A FLAT RIDGE FILLING IN BEHIND IT. THIS
WILL ALLOW SFC HIGH PRESENTLY OVER THE OHIO VALLEY TO SHIFT OVERHEAD
LEADING TO A CALM AND PLEASANT DAY. WEAK DISTURBANCES IN THE UPPER
FLOW ARE COLLOCATED WITH ENOUGH HIGH ALTITUDE MOISTURE TO EXPECT
INCREASING AMOUNTS OF CIRRUS THROUGH THE DAY. WINDS WILL DIMINISH
GOING INTO THE AFTERNOON ALONG WITH THE WEAKENING PRESSURE GRADIENT.
DESPITE WHAT DIFFUSION MIGHT OCCUR THROUGH THE CIRRUS HIGH TEMPS
SHOULD BE NEAR NORMAL.

AS NEXT SHORTWAVE DIGS IN BEHIND THE UPPER RIDGE OVER THE
SOUTHEAST...DEVELOPING A SFC LOW OVER THE LOWER MISS VALLEY...WARM
ADVECTION BEGINS ALOFT BY THE END OF THE DAY FRIDAY ON SOUTHERLY
WINDS. WINDS THROUGHOUT THE LOW TO MID LEVELS REMAIN WEAK BUT DO
IMPROVE TOWARD DAWN SATURDAY. DEEP LAYER MOISTURE IMPROVES PER
STEADILY INCREASING 1000-500MB RH OVERNIGHT. NONETHELESS ISENTROPIC
FIELDS SUGGEST FORCING FROM THE WARM ADVECTION WILL BE WEAK ON
ACCOUNT OF THE WEAK WINDS...WITH THE LLVL MOISTURE ARRIVING LATE IN
THE PERIOD. BEST FRONTOGENETIC FORCING COMES AROUND 600MB WITH POCKET
OF CHANNELED VORTICITY WHICH ARRIVES BY ABOUT 09Z SAT PER NAM...AND
THIS IS WHAT WARRANTS MENTIONABLE POPS. THERE IS DECENT AGREEMENT
AMONG NCEP MODELS AS WELL AS CMC GEM THAT A BAND OF PRECIP WILL
DEVELOP OVER OUR SW ZONES. THIS IS WHERE THE WARM ADVECTION IS
STRONGEST BUT PERHAPS UPSLOPING WILL AID PRECIP GENERATION AS WELL.
DESPITE THE MODEL CONSENSUS THE FORCING STILL REMAINS SOMEWHAT
QUESTIONABLE...SO I CHOSE TO KEEP CHC POPS AT BEST...AND MODEST QPF.
SFC HIGH MOVES INTO FAVORABLE POSITION FOR CAD DEVELOPMENT THOUGH
WITH THE PRECIP EXPECTED TO GET UNDERWAY LATE...HAVE KEPT LOW TEMPS
NEAR MOS CONSENSUS.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 250 AM FRIDAY...THE FRONTAL ZONE OVER THE TENN AND OHIO VALLEY
WILL REMAIN QUASI-STATIONARY AND UNDERGO GRADUAL FRONTOLYSIS THROUGH
THE SHORT TERM...AS AN UPPER LOW SLOWLY DRIFTS EAST AND FILLS. A
FETCH OF DEEP GULF MOISTURE WILL REMAIN OVER THE AREA THROUGH THE
PERIOD. THE MAIN SOURCE OF FORCING WILL GENERALLY BE TIED TO
MECHANICAL LIFT IN THE VICINITY OF THE HIGH TERRAIN...OWING TO
MODERATELY STRONG SOUTHERLY FLOW. HOWEVER...PERIODS OF WIDESPREAD
RAIN SHOULD ACCOMPANY THE APPROACH OF UPPER LEVEL SPEED MAXIMA. THIS
APPEARS MOST LIKELY LATE SATURDAY NIGHT AND EARLY SUNDAY...AND WE
HAVE FOCUSED THE HIGHEST POPS/QPF DURING THIS TIME. THE PATTERN
SUPERFICIALLY RESEMBLES A HEAVY/POSSIBLY EXCESSIVE RAINFALL EVENT
ACROSS OUR AREA...PARTICULARLY FOR THE SOUTHERN BLUE RIDGE AREAS...
IN LIGHT OF THE DURATION OF DEEP MOISTURE AND SOUTHERLY FLOW.
HOWEVER...THERE ARE SEVERAL LIMITING FACTORS...PROGGED PWAT
ANOMALIES ARE VERY MODEST...ONLY SLIGHTLY ABOVE CLIMO. WITH A COOL
AIR WEDGE EXPECTED TO BE IN PLACE UNTIL AT LEAST SUNDAY AFTERNOON...
THERE IS NOT MUCH IN THE WAY OF INSTABILITY EXPECTED DURING THIS
EVENT...AND IT CERTAINLY DOES NOT APPEAR THAT THE BEST PERIOD OF
FORCING WILL OVERLAP WITH SIGNIFICANT BUOYANCY. THERE IS ALSO SOME
DEGREE OF UNCERTAINTY REGARDING THE STRENGTH OF THE SOUTHERLY FLOW.
THEREFORE...WHILE THE SOUTHERN ESCARPMENT AREAS SHOULD CERTAINLY SEE
A NICE SOAK OVER THE TWO DAY PERIOD...EXCESSIVE RAINFALL
POSSIBILITIES ARE STILL VERY UNCERTAIN (BUT NOT OUT OF THE
QUESTION).

CONFIDENCE IN THE TEMPERATURE FORECAST IS LOWER THAN USUAL...OWING
TO THE LIKELIHOOD OF IN SITU CAD...BUT ALSO DUE TO UNCERTAINTY AS
TO EXACTLY WHEN IT WILL BECOME ESTABLISHED. WITH THE SURFACE HIGH
MOVING INTO AN INCREASINGLY UNFAVORABLE POSITION SUNDAY...IT ALSO
APPEARS THAT SOME AREAS WILL LIKELY SEE EROSION OF THE COLD POOL BY
THE END OF THE DAY...CREATING FURTHER COMPLICATIONS. REGARDLESS...
WITH WIDESPREAD CLOUD COVER EXPECTED THROUGH THE PERIOD...MAXES ARE
EXPECTED TO BE WELL BELOW NORMAL...WITH MINS AROUND TO SLIGHTLY
ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 320 AM FRIDAY...WITH THE FRONTAL ZONE WASHING OUT TO OUR
WEST...AND A WEAKNESS IN THE UPPER LEVEL HEIGHT FIELD PERSISTING...
THE AREA SHOULD REMAIN UNDER A FAIRLY MOIST AND INCREASINGLY
UNSTABLE AIR MASS THROUGH THE MEDIUM RANGE. THIS WILL SUPPORT
ISOLATED/SCT SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD...MAINLY
OF THE DIURNAL VARIETY. THERE COULD BE A BRIEF REPRIEVE BY THE END
OF THE PERIOD...AS THE GLOBAL MODELS HINT AT SURFACE LOW DEVELOPMENT
OFF THE SOUTHEAST COAST...WHICH COULD WRAP DRIER AIR INTO THE AREA.
HOWEVER...THIS IS QUITE UNCERTAIN AT THIS POINT...AND WITH THE
LIKELY APPROACH OF A FRONTAL BOUNDARY FROM THE WEST BY THE END OF
THE WEEK...WE DO NOT FEEL COMFORTABLE WITH A POP-LESS FORECAST AT
THIS POINT...SO SLIGHT/LOW CHANCE POPS WILL CARRY THROUGH TO
THURSDAY. TEMPS ARE EXPECTED TO HOVER AROUND CLIMO THROUGH THE
PERIOD.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
09Z KCLT UPDATE...AS HRRR AND RAP DEPICTED EARLIER THIS MORNING
COASTAL STRATUS ARE STRUGGLING TO PUSH FURTHER INLAND...SO STILL
CONFIDENT WITH VFR FCST IN THE NEAR TERM. FCST FOR THE DAYTIME TODAY
LOOKS GOOD AND AGREES WITH PUBLIC PACKAGE JUST RELEASED. PRECIP
CHANCES WILL INCREASE AROUND THE REGION LATE TONIGHT...THOUGH ANY
EFFECTS AT KCLT LOOK TO BE AFTER 06Z. LOWERING CLOUDS PRIOR TO THEN
THOUGH GUIDANCE AGREES THESE WILL REMAIN WELL INTO THE VFR RANGE.

PREV DISCUSSION...AT KCLT AND ELSEWHERE...IFR STRATUS PRESENT OVER
CAROLINA COASTAL PLAIN ATTM MAKING SOME WESTWARD PROGRESS. HRRR AND
RAP MESO MODELS SHOW THESE CLOUDS BUT DISSIPATE THEM WELL SOUTH AND
EAST OF THE NEAREST AFFECTED SITE /KCLT/. GIVEN LARGE DEWPOINT
DEPRESSIONS OVER THE FORECAST AREA AND SUBSIDENCE FROM BUILDING HIGH
PRESSURE...GOOD CONFIDENCE IN VFR THROUGH DAYBREAK AND THROUGH THE
TAF PERIOD AT THAT. NLY WINDS TONIGHT VEER THRU THE DAY TO ENE BY
AFTERNOON /SLY AT KAVL/...WITH WINDS RELAXING THRU THE DAY AS HIGH
BECOMES CENTERED OVERHEAD. CIRRUS WILL INCREASE BY AFTN AND
ESPECIALLY AFTER 00Z AS BETTER UPPER MOISTURE AND WEAK DISTURBANCES
PASS OVERHEAD.

OUTLOOK...THE NEXT SYSTEM WILL BRING MOISTURE BACK INTO THE AREA
FRIDAY NIGHT THRU THE WEEKEND. RESTRICTIONS IN CLOUDS/PRECIP WILL
LIKELY RETURN DURING THIS PERIOD...PERHAPS AS SOON AS 12Z SAT NEAR
THE BLUE RIDGE.

CONFIDENCE TABLE...

            08-14Z        14-20Z        20-02Z        02-08Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ010.
NC...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NCZ033-048>053-
     058-059-062>064-501-503-505.
     FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NCZ065-502-504-
     506>510.
SC...NONE.

&&

$$
SYNOPSIS...JDL
NEAR TERM...WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 336 AM EDT FRI APR 26 2013

.SYNOPSIS...
A DRY RIDGE OF HIGH PRESSURE WILL GIVE WAY TO A WEDGE OF MOIST AND
COOL AIR OVER THE WEEKEND. WEAK LOW PRESSURE WILL MOVE ACROSS THE
TENNESSEE VALLEY ALONG A STALLED COLD FRONT OVER THE WEEKEND. THE
FRONT WILL SLOWLY DISSIPATE AND THE COOL AIR WEDGE WILL GRADUALLY
WEAKEN INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM FRI...UPPER S/W TROUGH WILL CONTINUE TO ADVECT TOWARD THE
ATLANTIC THIS MORNING WITH A FLAT RIDGE FILLING IN BEHIND IT. THIS
WILL ALLOW SFC HIGH PRESENTLY OVER THE OHIO VALLEY TO SHIFT OVERHEAD
LEADING TO A CALM AND PLEASANT DAY. WEAK DISTURBANCES IN THE UPPER
FLOW ARE COLLOCATED WITH ENOUGH HIGH ALTITUDE MOISTURE TO EXPECT
INCREASING AMOUNTS OF CIRRUS THROUGH THE DAY. WINDS WILL DIMINISH
GOING INTO THE AFTERNOON ALONG WITH THE WEAKENING PRESSURE GRADIENT.
DESPITE WHAT DIFFUSION MIGHT OCCUR THROUGH THE CIRRUS HIGH TEMPS
SHOULD BE NEAR NORMAL.

AS NEXT SHORTWAVE DIGS IN BEHIND THE UPPER RIDGE OVER THE
SOUTHEAST...DEVELOPING A SFC LOW OVER THE LOWER MISS VALLEY...WARM
ADVECTION BEGINS ALOFT BY THE END OF THE DAY FRIDAY ON SOUTHERLY
WINDS. WINDS THROUGHOUT THE LOW TO MID LEVELS REMAIN WEAK BUT DO
IMPROVE TOWARD DAWN SATURDAY. DEEP LAYER MOISTURE IMPROVES PER
STEADILY INCREASING 1000-500MB RH OVERNIGHT. NONETHELESS ISENTROPIC
FIELDS SUGGEST FORCING FROM THE WARM ADVECTION WILL BE WEAK ON
ACCOUNT OF THE WEAK WINDS...WITH THE LLVL MOISTURE ARRIVING LATE IN
THE PERIOD. BEST FRONTOGENETIC FORCING COMES AROUND 600MB WITH POCKET
OF CHANNELED VORTICITY WHICH ARRIVES BY ABOUT 09Z SAT PER NAM...AND
THIS IS WHAT WARRANTS MENTIONABLE POPS. THERE IS DECENT AGREEMENT
AMONG NCEP MODELS AS WELL AS CMC GEM THAT A BAND OF PRECIP WILL
DEVELOP OVER OUR SW ZONES. THIS IS WHERE THE WARM ADVECTION IS
STRONGEST BUT PERHAPS UPSLOPING WILL AID PRECIP GENERATION AS WELL.
DESPITE THE MODEL CONSENSUS THE FORCING STILL REMAINS SOMEWHAT
QUESTIONABLE...SO I CHOSE TO KEEP CHC POPS AT BEST...AND MODEST QPF.
SFC HIGH MOVES INTO FAVORABLE POSITION FOR CAD DEVELOPMENT THOUGH
WITH THE PRECIP EXPECTED TO GET UNDERWAY LATE...HAVE KEPT LOW TEMPS
NEAR MOS CONSENSUS.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 250 AM FRIDAY...THE FRONTAL ZONE OVER THE TENN AND OHIO VALLEY
WILL REMAIN QUASI-STATIONARY AND UNDERGO GRADUAL FRONTOLYSIS THROUGH
THE SHORT TERM...AS AN UPPER LOW SLOWLY DRIFTS EAST AND FILLS. A
FETCH OF DEEP GULF MOISTURE WILL REMAIN OVER THE AREA THROUGH THE
PERIOD. THE MAIN SOURCE OF FORCING WILL GENERALLY BE TIED TO
MECHANICAL LIFT IN THE VICINITY OF THE HIGH TERRAIN...OWING TO
MODERATELY STRONG SOUTHERLY FLOW. HOWEVER...PERIODS OF WIDESPREAD
RAIN SHOULD ACCOMPANY THE APPROACH OF UPPER LEVEL SPEED MAXIMA. THIS
APPEARS MOST LIKELY LATE SATURDAY NIGHT AND EARLY SUNDAY...AND WE
HAVE FOCUSED THE HIGHEST POPS/QPF DURING THIS TIME. THE PATTERN
SUPERFICIALLY RESEMBLES A HEAVY/POSSIBLY EXCESSIVE RAINFALL EVENT
ACROSS OUR AREA...PARTICULARLY FOR THE SOUTHERN BLUE RIDGE AREAS...
IN LIGHT OF THE DURATION OF DEEP MOISTURE AND SOUTHERLY FLOW.
HOWEVER...THERE ARE SEVERAL LIMITING FACTORS...PROGGED PWAT
ANOMALIES ARE VERY MODEST...ONLY SLIGHTLY ABOVE CLIMO. WITH A COOL
AIR WEDGE EXPECTED TO BE IN PLACE UNTIL AT LEAST SUNDAY AFTERNOON...
THERE IS NOT MUCH IN THE WAY OF INSTABILITY EXPECTED DURING THIS
EVENT...AND IT CERTAINLY DOES NOT APPEAR THAT THE BEST PERIOD OF
FORCING WILL OVERLAP WITH SIGNIFICANT BUOYANCY. THERE IS ALSO SOME
DEGREE OF UNCERTAINTY REGARDING THE STRENGTH OF THE SOUTHERLY FLOW.
THEREFORE...WHILE THE SOUTHERN ESCARPMENT AREAS SHOULD CERTAINLY SEE
A NICE SOAK OVER THE TWO DAY PERIOD...EXCESSIVE RAINFALL
POSSIBILITIES ARE STILL VERY UNCERTAIN (BUT NOT OUT OF THE
QUESTION).

CONFIDENCE IN THE TEMPERATURE FORECAST IS LOWER THAN USUAL...OWING
TO THE LIKELIHOOD OF IN SITU CAD...BUT ALSO DUE TO UNCERTAINTY AS
TO EXACTLY WHEN IT WILL BECOME ESTABLISHED. WITH THE SURFACE HIGH
MOVING INTO AN INCREASINGLY UNFAVORABLE POSITION SUNDAY...IT ALSO
APPEARS THAT SOME AREAS WILL LIKELY SEE EROSION OF THE COLD POOL BY
THE END OF THE DAY...CREATING FURTHER COMPLICATIONS. REGARDLESS...
WITH WIDESPREAD CLOUD COVER EXPECTED THROUGH THE PERIOD...MAXES ARE
EXPECTED TO BE WELL BELOW NORMAL...WITH MINS AROUND TO SLIGHTLY
ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 320 AM FRIDAY...WITH THE FRONTAL ZONE WASHING OUT TO OUR
WEST...AND A WEAKNESS IN THE UPPER LEVEL HEIGHT FIELD PERSISTING...
THE AREA SHOULD REMAIN UNDER A FAIRLY MOIST AND INCREASINGLY
UNSTABLE AIR MASS THROUGH THE MEDIUM RANGE. THIS WILL SUPPORT
ISOLATED/SCT SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD...MAINLY
OF THE DIURNAL VARIETY. THERE COULD BE A BRIEF REPRIEVE BY THE END
OF THE PERIOD...AS THE GLOBAL MODELS HINT AT SURFACE LOW DEVELOPMENT
OFF THE SOUTHEAST COAST...WHICH COULD WRAP DRIER AIR INTO THE AREA.
HOWEVER...THIS IS QUITE UNCERTAIN AT THIS POINT...AND WITH THE
LIKELY APPROACH OF A FRONTAL BOUNDARY FROM THE WEST BY THE END OF
THE WEEK...WE DO NOT FEEL COMFORTABLE WITH A POP-LESS FORECAST AT
THIS POINT...SO SLIGHT/LOW CHANCE POPS WILL CARRY THROUGH TO
THURSDAY. TEMPS ARE EXPECTED TO HOVER AROUND CLIMO THROUGH THE
PERIOD.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...IFR STRATUS PRESENT OVER CAROLINA COASTAL
PLAIN ATTM MAKING SOME WESTWARD PROGRESS. HRRR AND RAP MESO MODELS
SHOW THESE CLOUDS BUT DISSIPATE THEM WELL SOUTH AND EAST OF THE
NEAREST AFFECTED SITE /KCLT/. GIVEN LARGE DEWPOINT DEPRESSIONS OVER
THE FORECAST AREA AND SUBSIDENCE FROM BUILDING HIGH PRESSURE...GOOD
CONFIDENCE IN VFR THROUGH DAYBREAK AND THROUGH THE TAF PERIOD AT
THAT. NLY WINDS TONIGHT VEER THRU THE DAY TO ENE BY AFTERNOON /SLY
AT KAVL/...WITH WINDS RELAXING THRU THE DAY AS HIGH BECOMES CENTERED
OVERHEAD. CIRRUS WILL INCREASE BY AFTN AND ESPECIALLY AFTER 00Z AS
BETTER UPPER MOISTURE AND WEAK DISTURBANCES PASS OVERHEAD.

OUTLOOK...THE NEXT SYSTEM WILL BRING MOISTURE BACK INTO THE AREA
FRIDAY NIGHT THRU THE WEEKEND. RESTRICTIONS IN CLOUDS/PRECIP WILL
LIKELY RETURN DURING THIS PERIOD...PERHAPS AS SOON AS 12Z SAT NEAR
THE BLUE RIDGE.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-07Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ010.
NC...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NCZ033-048>053-
     058-059-062>064-501-503-505.
     FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NCZ065-502-504-
     506>510.
SC...NONE.

&&

$$
SYNOPSIS...JDL
NEAR TERM...WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 145 AM EDT FRI APR 26 2013

.SYNOPSIS...
MILD HIGH PRESSURE WILL REMAIN ACROSS THE SOUTHEAST THROUGH TODAY.
A LOW IN THE SOUTHERN PLAINS WILL APPROACH THE AREA LATE TONIGHT
AND DRIFT NORTHEASTWARD THROUGH THE WEEKEND. HIGH PRESSURE WILL
BUILD BACK IN FOR THE FIRST PART OF THE WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
115 AM UPDATE...FCST TEMPS FROM PREV SHIFT ARE WELL BELOW ALL NEW
GUIDANCE...THE LATTER GENERALLY NOT SUPPORTING FROST/FREEZE
HEADLINES. SOME MOUNTAIN VALLEYS ARE ALREADY IN THE MID 30S AND WITH
SFC HIGH BUILDING TO OUR WEST...AND MOVING OUR WAY BEHIND DEPARTING
SHORTWAVE TROUGH...RADIATIONAL COOLING SHOULD CONTINUE TO IMPROVE
AND MAKE THE BEST OF THE DRY DEWPOINTS /GENERALLY 28-32F/ IN THE
MTNS/FOOTHILLS. REVISED TRENDS SLIGHTLY WARMER BUT STILL EXPECT THE
FROST/FREEZE TO BE POSSIBLE...AND WILL MAINTAIN CURRENT HEADLINES.

AS OF 230 PM...LATEST SATELLITE IMAGES INDICATED CLEAR CONDITIONS
ACROSS THE FORECAST AREA AND UPSTREAM. HIGH PRESSURE WILL BUILD
OVER THE REGION THIS EVENING AND OVERNIGHT. AS HIGH PRESSURE
APPROACHES...A DRY COLD FRONT IS EXPECTED TO PUSH OVER THE SOUTHERN
APPALACHIANS. THE WINDS IN THE WAKE OF THE FRONT MAY REMAIN STEADY
FROM THE NNW...BUT SHOULD BECOME LIGHT DURING THE PRE DAWN HOURS.
THE COMBINATION OF CLEAR SKY...LIGHT TO CALM WINDS...AND WIDE
EVENING DEWPOINT DEPRESSIONS SHOULD SUPPORT STEADY COOLING
OVERNIGHT. MIN TEMPERATURES ARE FORECAST TO RANGE IN THE UPPER 20S
TO LOW 30S ACROSS MOST OF THE NC MTNS. FOOTHILL AREAS MAY SUPPORT
AREAS TO WIDESPREAD FROST...AREAS EAST WILL REMAIN TOO WARM FOR
FROST BY 6 TO 8 DEGREES BELOW NORMAL. THE CURRENT FREEZE WARNING AND
FROST ADVISORY IS WELL PLACED AND TIMED...NO CHANGES PLANNED FOR
THIS FORECAST PACKAGE.

FRIDAY...THE WEATHER WILL REMAIN FAIR UNDER RIDGE OF HIGH PRESSURE.
I WILL FORECAST HIGH CLOUDS INCREASING FROM THE
EAST...OTHERWISE...CONDITIONS SHOULD FAVOR MOSTLY TO PARTLY SUNNY.
HIGH TEMPERATURES ARE FORECAST TO PEAK WITHIN 2 TO 4 DEGREES OF
NORMAL.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 PM EDT THU...A POSITIVE TILT SRN STREAM WAVE WILL MOVE
ACROSS THE SRN TIER OF THE CONUS FRI NIGHT...WITH THE MAIN H5 LOW
CENTER LIFTING UP THE OH VALLEY OVER THE WEEKEND. MOISTURE WILL
DEEPEN ACROSS THE REGION FRI NIGHT THROUGH SAT...ALONG WITH
IMPROVING UPPER LEVEL DIVERGENCE AS A JETLET MOVES E OFF THE
DELMARVA COAST. LOWER LEVELS SHOULD BE A BIT SLOWER TO MOISTEN UP
THROUGH SAT...BUT WITH LIKELY POPS W TO CHC E STILL EXPECTED IN
GRADUALLY IMPROVING SRLY FLOW LATE DAY SAT. THE INCREASING CLOUDS
SHOULD KEEP TEMPS NEARLY 10 DEGREES BELOW NORMAL MOST AREAS.

A DEEPER SRLY FETCH OF MOISTURE WILL ARRIVE SAT NIGHT THROUGH
SUNDAY...AS A BETTER BAROCLINIC ZONE SETS UP ACROSS THE REGION TO
IMPROVE UPGLIDE. POPS HAVE BEEN PUSHED INTO THE HIGH LIKELY/LOW
CATEGORICAL RANGE BY MIDDAY SUNDAY. MAX TEMPERATURES WILL BE EVEN
COOLER ON SUNDAY AS UPGLIDE CREATES MORE PRECIPITATION INTO A WEAK
HYBRID CAD SFC LAYER ACROSS THE REGION. INSTABILITY SHOULD REMAIN
SHUNTED SW OF THE DEVELOPING SFC CAD FRONT...WITH LOW END THUNDER
CHANCES ONLY ALONG THE SW FRINGE SUNDAY. PRECIPITATION RATES SHOULD
BE TOO LOW FOR ANY HYDRO PROBLEMS TO DEVELOP...WITH BETTER RATES S
AND SW OF THE FORECAST AREA IN THE MORE UNSTABLE AIR. A WEAK COLD
FRONT WILL THEN ARRIVE FROM THE WEST SUNDAY NIGHT...ACCOMPANIED BY
MID LEVEL DRYING TO TAPER POPS QUICKLY DOWN INTO THE CHC RANGE.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 PM EDT THU...HEIGHTS WILL RISE SLIGHTLY ALONG THE ERN
SEABOARD ON MONDAY AS A DAMPENING UPPER WAVE MOVES OFF THE MID
ATLANTIC COAST...WITH ADDITIONAL MID LEVEL DRYING OCCURRING.
HOWEVER...A WEAKNESS WILL REMAIN OVER THE LOWER MS RIVER VALLEY ON
MON AND DRIFT SLOWLY EWD ACROSS THE DEEP SOUTH THROUGH AT LEAST MID
WEEK. IN ADDITION...PERSISTENT EASTERLY FLOW AROUND THE OFFSHORE
RIDGE WILL PUMP ATLANTIC MOISTURE BACK INTO THE REGION. THIS WILL
SURELY CONTRIBUTE TO AN EXTENDED MOSTLY CLOUDY PERIOD THROUGH AT
LEAST MID WEEK. WILL FEATURE A SLIGHT DIURNAL PATTERN TO DAILY ISOLD
TO SCT SHOWER COVERAGE ACROSS THE AREA. A PERSISTENT PATTERN OF WARM
OVERNIGHT MINS AND WELL BELOW NORMAL AFTN MAXES WILL CONTINUE
THROUGH THE PERIOD.

A COLD FRONT MAY APPROACH FROM THE WEST ON THURSDAY...BUT WITH
CONSIDERABLE MODEL SPREAD ON TIMING. IN ADDITION...THE RIDGE OVER
THE NE U.S. MAY BECOME STRONG ENOUGH TO WRAP SOME DRIER AIR IN ON NE
FLOW. THIS MAKES THE LATER WEEK FORECAST MUCH MORE UNCERTAIN. WILL
FEATURE PERSISTENCE FOR NOW.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...IFR STRATUS PRESENT OVER CAROLINA COASTAL
PLAIN ATTM MAKING SOME WESTWARD PROGRESS. HRRR AND RAP MESO MODELS
SHOW THESE CLOUDS BUT DISSIPATE THEM WELL SOUTH AND EAST OF THE
NEAREST AFFECTED SITE /KCLT/. GIVEN LARGE DEWPOINT DEPRESSIONS OVER
THE FORECAST AREA AND SUBSIDENCE FROM BUILDING HIGH PRESSURE...GOOD
CONFIDENCE IN VFR THROUGH DAYBREAK AND THROUGH THE TAF PERIOD AT
THAT. NLY WINDS TONIGHT VEER THRU THE DAY TO ENE BY AFTERNOON /SLY
AT KAVL/...WITH WINDS RELAXING THRU THE DAY AS HIGH BECOMES CENTERED
OVERHEAD. CIRRUS WILL INCREASE BY AFTN AND ESPECIALLY AFTER 00Z AS
BETTER UPPER MOISTURE AND WEAK DISTURBANCES PASS OVERHEAD.

OUTLOOK...THE NEXT SYSTEM WILL BRING MOISTURE BACK INTO THE AREA
FRIDAY NIGHT THRU THE WEEKEND. RESTRICTIONS IN CLOUDS/PRECIP WILL
LIKELY RETURN DURING THIS PERIOD...PERHAPS AS SOON AS 12Z SAT NEAR
THE BLUE RIDGE.

CONFIDENCE TABLE...

            05-11Z        11-17Z        17-23Z        23-05Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ010.
NC...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NCZ033-048>053-
     058-059-062>064-501-503-505.
     FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NCZ065-502-504-
     506>510.
SC...NONE.

&&

$$
SYNOPSIS...PAT
NEAR TERM...NED/WIMBERLEY
SHORT TERM...HG
LONG TERM...HG
AVIATION...WIMBERLEY







AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 606 PM CDT FRI APR 26 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 259 PM CDT FRI APR 26 2013

VERY LITTLE OF SIGNIFICANCE TONIGHT AND SATURDAY ACROSS THE AREA AS
SYSTEMS DIVERT AROUND THE REGION. FRONTAL BOUNDARY HAS COMPLETELY
CLEARED THE FAR SOUTHEAST CWA AT MID AFTERNOON...WITH VERY MIXY
LOWER ATMOSPHERE DRIVING A DECENT NORTHWEST TO NORTHEAST WIND ACROSS
THE AREA. WINDS WILL DECOUPLE FAIRLY QUICKLY AS SUNSET...WITH WEAK
SURFACE RIDGE CENTERED OVER THE AREA OVERNIGHT. VERY DRY AIRMASS
OVER THE WESTERN HALF...SO EXPECT THAT WILL BE FAIRLY EFFICIENT IN
COOLING THIS EVENING AND IN THE OVERNIGHT WITH THE WEAK FLOW.  NOT
EXPECTING ANY SIGNIFICANT FOG POTENTIAL...BUT MAY GET SOME 4-6SM
DEVELOPMENT IN SHALLOW AREAS THROUGH THE MID CWA. FRONTAL BOUNDARY
WILL WASH OUT TO THE SOUTH...WITH SOUTHERLY FLOW GRADUALLY BECOMING
ESTABLISHED...STRONGEST ACROSS THE WEST. MODELS HAVE REPEATEDLY BEEN
ABOUT 2C TOO COOL ON 925 HPA TEMPS FOR THE NEXT DAY...AND RAP HAS
PROVIDED A MUCH BETTER FORECAST ONCE IT HAS FALLEN INTO THE RANGE.
THEREFORE...ACTUALLY RAISED TEMPERATURES SOMEWHAT HIGHER THAN
GUIDANCE...BUT ONLY A COUPLE DEGREES AS WILL BE A MORE STABLE WARM
ADVECTIVE PROFILE INSTEAD OF THE WEAK COLD ADVECTION TODAY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 259 PM CDT FRI APR 26 2013

SATURDAY NIGHT WILL SEE A DECENT SOUTHERLY GRADIENT THROUGH THE
NIGHT WHICH WILL KEEP MILD TEMPERATURES IN PLACE. THIS WILL KEEP
LOWS ABOVE NORMAL AND MAINLY IN THE UPPER 40S TO AROUND 50. COULD
ACTUALLY SEE THEM A LITTLE WARMER OF THE GRADIENT REMAINS STRONG
ENOUGH.

A COLD FRONT WILL SWING INTO THE AREA ON SUNDAY WHICH MAY SPARK A
FEW SHOWERS AND THUNDERSTORMS OVER THE EASTERN CWA DURING THE DAY
AND INTO THE EVENING. UPPER LEVEL SUPPORT WILL ALSO BRING A CHANCE
FOR SHOWERS INTO THE WESTERN AND SOUTHERN CWA DURING THE NIGHT.
AHEAD OF THIS FRONT TEMPERATURES WILL CLIMB WELL ABOVE NORMAL AND
MUCH OF THE AREA WILL CLIMB INTO THE UPPER 70S TO LOWER 80S.

SUNDAY NIGHT INTO MONDAY WILL BE A MILD PERIOD WITH THE FRONT
SETTLING IN AND COOLER TEMPERATURES. THE BETTER CHANCE FOR SHOWERS
WILL BE IN THE SOUTHERN CWA. INSTABILITY MARGINAL SO ONLY A MINOR
THREAT FOR THUNDERSTORMS...THE BETTER CHANCE WILL BE SUNDAY
AFTERNOON OVER THE EASTERN CWA. WHILE MONDAY WILL BE COOLER STILL
ANTICIPATING UPPER 60S TO LOWER 70S.

SOME UNFORTUNATE BIG CHANGES COMING IN THE EXTENDED AS A LARGE
TROUGH OF LOW PRESSURE GRADUALLY DIGS ACROSS THE NORTHERN AND
CENTRAL PLAINS. THIS WILL BRING AN END TO THE WARM STRETCH WITH
BELOW NORMAL TEMPERATURES AGAIN BLANKETING THE REGION FOR THE
REMAINDER OF THE WEEK. THE GFS COMES IN QUITE A BIT DEEPER WITH THE
CUT OFF LOW THAT DEVELOPS...DROPPING IT SOUTH INTO KENTUCKY BY THE
WEEKEND WHILE THE ECMWF CUTS THIS LOW OFF IN NORTHERN
WISCONSIN...ALTHOUGH THE NEW 12Z ECMWF NOW CUTS THIS LOW OFF IN
NEBRASKA. SO...THE MAIN STORY HERE IS A VERY UNPREDICTABLE CUT OFF
LOW BUT COLDER TEMPERATURES. THERE DOES APPEAR TO BE SOME DECENT
UPPER LEVEL SUPPORT THAT DROPS SOUTH MID WEEK AND WILL HAVE SOME
POPS IN TO COVER THIS OTHERWISE AT THIS TIME NOT LOOKING LIKE ANY
MAJOR SYSTEMS. CONFIDENCE AFTER WEDNESDAY LOW.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 605 PM CDT FRI APR 26 2013

VFR THROUGH 00Z SUNDAY.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...







AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 314 PM CDT FRI APR 26 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 259 PM CDT FRI APR 26 2013

VERY LITTLE OF SIGNIFICANCE TONIGHT AND SATURDAY ACROSS THE AREA AS
SYSTEMS DIVERT AROUND THE REGION. FRONTAL BOUNDARY HAS COMPLETELY
CLEARED THE FAR SOUTHEAST CWA AT MID AFTERNOON...WITH VERY MIXY
LOWER ATMOSPHERE DRIVING A DECENT NORTHWEST TO NORTHEAST WIND ACROSS
THE AREA. WINDS WILL DECOUPLE FAIRLY QUICKLY AS SUNSET...WITH WEAK
SURFACE RIDGE CENTERED OVER THE AREA OVERNIGHT. VERY DRY AIRMASS
OVER THE WESTERN HALF...SO EXPECT THAT WILL BE FAIRLY EFFICIENT IN
COOLING THIS EVENING AND IN THE OVERNIGHT WITH THE WEAK FLOW.  NOT
EXPECTING ANY SIGNIFICANT FOG POTENTIAL...BUT MAY GET SOME 4-6SM
DEVELOPMENT IN SHALLOW AREAS THROUGH THE MID CWA. FRONTAL BOUNDARY
WILL WASH OUT TO THE SOUTH...WITH SOUTHERLY FLOW GRADUALLY BECOMING
ESTABLISHED...STRONGEST ACROSS THE WEST. MODELS HAVE REPEATEDLY BEEN
ABOUT 2C TOO COOL ON 925 HPA TEMPS FOR THE NEXT DAY...AND RAP HAS
PROVIDED A MUCH BETTER FORECAST ONCE IT HAS FALLEN INTO THE RANGE.
THEREFORE...ACTUALLY RAISED TEMPERATURES SOMEWHAT HIGHER THAN
GUIDANCE...BUT ONLY A COUPLE DEGREES AS WILL BE A MORE STABLE WARM
ADVECTIVE PROFILE INSTEAD OF THE WEAK COLD ADVECTION TODAY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 259 PM CDT FRI APR 26 2013

SATURDAY NIGHT WILL SEE A DECENT SOUTHERLY GRADIENT THROUGH THE
NIGHT WHICH WILL KEEP MILD TEMPERATURES IN PLACE. THIS WILL KEEP
LOWS ABOVE NORMAL AND MAINLY IN THE UPPER 40S TO AROUND 50. COULD
ACTUALLY SEE THEM A LITTLE WARMER OF THE GRADIENT REMAINS STRONG
ENOUGH.

A COLD FRONT WILL SWING INTO THE AREA ON SUNDAY WHICH MAY SPARK A
FEW SHOWERS AND THUNDERSTORMS OVER THE EASTERN CWA DURING THE DAY
AND INTO THE EVENING. UPPER LEVEL SUPPORT WILL ALSO BRING A CHANCE
FOR SHOWERS INTO THE WESTERN AND SOUTHERN CWA DURING THE NIGHT.
AHEAD OF THIS FRONT TEMPERATURES WILL CLIMB WELL ABOVE NORMAL AND
MUCH OF THE AREA WILL CLIMB INTO THE UPPER 70S TO LOWER 80S.

SUNDAY NIGHT INTO MONDAY WILL BE A MILD PERIOD WITH THE FRONT
SETTLING IN AND COOLER TEMPERATURES. THE BETTER CHANCE FOR SHOWERS
WILL BE IN THE SOUTHERN CWA. INSTABILITY MARGINAL SO ONLY A MINOR
THREAT FOR THUNDERSTORMS...THE BETTER CHANCE WILL BE SUNDAY
AFTERNOON OVER THE EASTERN CWA. WHILE MONDAY WILL BE COOLER STILL
ANTICIPATING UPPER 60S TO LOWER 70S.

SOME UNFORTUNATE BIG CHANGES COMING IN THE EXTENDED AS A LARGE
TROUGH OF LOW PRESSURE GRADUALLY DIGS ACROSS THE NORTHERN AND
CENTRAL PLAINS. THIS WILL BRING AN END TO THE WARM STRETCH WITH
BELOW NORMAL TEMPERATURES AGAIN BLANKETING THE REGION FOR THE
REMAINDER OF THE WEEK. THE GFS COMES IN QUITE A BIT DEEPER WITH THE
CUT OFF LOW THAT DEVELOPS...DROPPING IT SOUTH INTO KENTUCKY BY THE
WEEKEND WHILE THE ECMWF CUTS THIS LOW OFF IN NORTHERN
WISCONSIN...ALTHOUGH THE NEW 12Z ECMWF NOW CUTS THIS LOW OFF IN
NEBRASKA. SO...THE MAIN STORY HERE IS A VERY UNPREDICTABLE CUT OFF
LOW BUT COLDER TEMPERATURES. THERE DOES APPEAR TO BE SOME DECENT
UPPER LEVEL SUPPORT THAT DROPS SOUTH MID WEEK AND WILL HAVE SOME
POPS IN TO COVER THIS OTHERWISE AT THIS TIME NOT LOOKING LIKE ANY
MAJOR SYSTEMS. CONFIDENCE AFTER WEDNESDAY LOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1230 PM CDT FRI APR 26 2013

VFR CONDITIONS WILL PREVAIL THROUGH 18Z SAT. SOME MVFR CONDITIONS
WILL BE POSSIBLE IN FOG FOR KHON AND KFSD LATE NIGHT/EARLY MORNING WITH
LIGHT FLOW.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...CHAPMAN







AREA FORECAST DISCUSSION

NWS AUSTIN/SAN ANTONIO TX

 1155 PM CDT THU APR 25 2013

.AVIATION...
A SURFACE TROUGH ALONG THE LOWER TEXAS COAST LATE THIS EVENING
TO CONTINUE MOVING NORTHWARD DURING THE OVERNIGHT HOURS AS AN
UPPER LEVEL DISTURBANCE CROSSES SOUTH CENTRAL TEXAS. WITH SURFACE
DEWPOINTS IN THE MID 40S ACROSS MUCH OF OUR AREA AND MID 50S
ACROSS THE COASTAL PLAINS AS OF 04Z...WITH MORE MOISTURE POOLING
EXPECTED OVERNIGHT AND EARLY FRIDAY...MVFR/IFR CONDITIONS ARE
EXPECTED ACROSS AREA TERMINALS THROUGH MIDDAY FRIDAY. ALSO...LIGHT
RAIN OR DRIZZLE IS EXPECTED FOR THE OVERNIGHT/FRIDAY MORNING PERIOD.
THERE MAY BE A TIME WHERE CIGS AND VSBYS COULD DROP TO LIFR
CATEGORY AROUND 12Z/14Z ALONG I-35 SITES. MVFR/VFR CONDITIONS ARE
EXPECTED TO RETURN AFTER 17Z FRIDAY. SOUTHEASTERLY FLOW WILL
PREVAIL FOR MUCH OF THE FORECAST PERIOD WITH WIND SPEEDS OF 4 TO 9
KNOTS OVERNIGHT INCREASING TO 10 TO 15 KNOTS WITH HIGHER GUSTS
FRIDAY AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 952 PM CDT THU APR 25 2013/

UPDATE...
A SURFACE TROUGH IS ALONG THE LOWER TEXAS COAST WITH A WARM FRONT
DEVELOPING ALONG THE COAST. THE WARM FRONT WILL MOVE NORTH DURING
THE OVERNIGHT HOURS AS THE LEFT ENTRANCE REGION OF AN UPPER LEVEL
JET AND A WEAK MID LEVEL SHORT-WAVE MOVE ACROSS SOUTHERN TEXAS.
UPWARD FORCING FROM THESE FEATURES WILL CAUSE PATCHY LIGHT RAIN OR
DRIZZLE TO DEVELOP ACROSS SOUTH CENTRAL TEXAS DURING THE OVERNIGHT
HOURS AS MENTIONED IN ONGOING FORECAST. TEMPERATURES RUNNING A
DEGREE OR SO WARMER THAN FORECAST AND HAVE BOOSTED THEM SIMILARLY
FOR THE REMAINDER OF TONIGHT INTO FRIDAY MORNING. SOME AREAS MAY
SEE THEIR NIGHTTIME LOW IN THE NEXT FEW HOURS AND THEN RISE TOWARD
MORNING AS DEWPOINTS CONTINUE TO INCREASE. REMAINDER OF SOUTH
CENTRAL TEXAS FORECAST IS ON TRACK. CHANCES OF RAIN TREND HIGHER
FOR THIS WEEKEND AS A SURFACE BOUNDARY AND SERIES OF WEAK UPPER
LEVEL SHORT-WAVES INTERACT WITH INCREASING MOISTURE LEVELS TO
ABOVE SEASONAL AVERAGES TO GENERATE ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS. THERE IS A POTENTIAL FOR STRONG TO MARGINALLY
SEVERE STORMS TO DEVELOP ALONG THE FRONT OVER CENTRAL TEXAS AND
OVER THE SERRANIAS DEL BURRO MOUNTAINS OF MEXICO AND THEN MOVE
ACROSS SOUTH CENTRAL TEXAS ESPECIALLY SATURDAY AND SUNDAY NIGHTS.

PREV DISCUSSION... /ISSUED 618 PM CDT THU APR 25 2013/

AVIATION...
A SERIES OF UPPER SHORT-WAVE DISTURBANCES WILL COME ACROSS SOUTH
CENTRAL TEXAS TONIGHT AND FRIDAY AS MAIN UPPER TROUGH CROSSES THE
FOUR CORNERS REGION TONIGHT AND OVER THE TEXAS PANHANDLE FRIDAY
MORNING. SOUTHEAST LOW LEVEL FLOW CONTINUES TO DOMINATE WITH
DEWPOINTS IN THE UPPER 40S LATE THIS AFTERNOON...BUT INCREASING
TO THE 50S AND 60S OVERNIGHT ACCORDING TO HIRES SOLUTIONS AND
LATEST RUC13 GUIDANCE. THEREFORE...EXPECT CIGS TO LOWER TO MVFR
AROUND 03Z TONIGHT AND LOWERING TO IFR AROUND OR AFTER 07Z...WITH
POSSIBLE DRIZZLE/LIGHT RAIN ACROSS THE I-35 TERMINALS THROUGH 16Z
FRIDAY. MVFR CONDITIONS WILL RETURN AND PREVAIL FOR THE REMAINDER
OF THE FORECAST CYCLE. ACROSS KDRT...MVFR CIGS ARE EXPECTED
AROUND 04Z TONIGHT AND PREVAIL TO ABOUT 17Z WITH VFR CONDITIONS
RETURNING AFTERWARDS. SOUTHEASTERLY WINDS 4 TO 9 KNOTS ARE
ANTICIPATED TONIGHT AND FRIDAY MORNING INCREASING 10 TO 15 KNOTS
FRIDAY AFTERNOON.

PREV DISCUSSION... /ISSUED 313 PM CDT THU APR 25 2013/

SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
BOUNDARY LAYER WINDS HAVE BEGUN TO SHIFT TO THE EAST AND WILL
CONTINUE TO VEER TO THE SOUTHEAST TONIGHT. THE ONSHORE FLOW WILL
ADVECT GULF MOISTURE INTO THE REGION...KEEPING OVERCAST SKIES AND
MILD TEMPERATURES TONIGHT. THE WARM AIR ADVECTION AND REMAINING
SUBTLE ISENTROPIC LIFT SUGGEST THE POTENTIAL FOR ANOTHER ROUND OF
EARLY MORNING LIGHT RAIN SHOWERS. SOME BREAKS IN THE CLOUD DECK
ARE EXPECTED FRIDAY AFTERNOON WITH HIGHS REBOUNDING TO THE MID
70S TO LOW 80S. AN UPPER LEVEL LOW CURRENTLY MOVING ACROSS THE
DESERT SOUTHWEST WILL EJECT TOWARD THE PLAINS STATES AS AN OPEN
WAVE ON FRIDAY. THIS FEATURE WILL PROVIDE FOCUS FOR CONVECTION
WELL NORTH OF OUR AREA...BUT COULD SEE ISOLATED SHOWERS/THUNDERSTORMS
FRIDAY AFTERNOON ACROSS OUR NERN AREAS. FRIDAY NIGHT WILL BE MILD
AND HUMID...BUT CHANCES FOR RAIN WILL BE WELL TO OUR NORTHEAST.

LONG TERM (SATURDAY THROUGH THURSDAY)...
A COLD FRONTAL BOUNDARY IN ASSOCIATION WITH THE SHORT-WAVE TROUGH
WILL SKIRT ACROSS THE RED RIVER VALLEY FRIDAY NIGHT AND WILL STALL
ACROSS CENTRAL TEXAS ON SATURDAY. THE FRONT IS NOT EXPECTED TO
PUSH INTO OUR AREA...BUT WILL PROVIDE A FOCUS FOR ADDITIONAL
CONVECTIVE ACTIVITY SATURDAY AND SATURDAY NIGHT. THERE IS ALSO THE
POTENTIAL FOR ELEVATED CONVECTION TO DEVELOP ACROSS THE SERRANIAS
DEL BURRO IN NERN MEXICO...AND A FEW STORMS MAY DRIFT ACROSS THE
RIO GRANDE SATURDAY NIGHT/SUNDAY MORNING. WEAK ZONAL FLOW
PREVAILING ALOFT AND THE LINGERING WASHED-OUT FRONTAL BOUNDARY
WILL KEEP CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE REGION ON SUNDAY. BY SUNDAY NIGHT THE MOISTURE AXIS SHIFTS TO
THE RIO GRANDE WITH ANOTHER ROUND OF BURRO MOUNTAIN STORMS
POSSIBLE. THESE STORMS ARE KNOWN FOR THEIR POTENTIAL TO REACH
SEVERE LEVELS AND/OR DEVELOP INTO MESO-SCALE CONVECTIVE SYSTEMS.
OTHERWISE...THE SLOPPY PATTERN ALOFT WILL GENERALLY KEEP
CONVECTIVE ACTIVITY SUB-SEVERE...BUT COULD SEE A FEW STORMS
STRENGTHENED BY DIURNAL HEATING AND OUTFLOW BOUNDARIES AND
POTENTIALLY BECOME STRONG.

THE FRONT WILL RETREAT NORTHWARD ON MONDAY...BUT A WEAK UPPER
DISTURBANCE WILL MOVE ACROSS THE REGION...KEEPING MENTIONABLE POPS
IN THE FORECAST MONDAY AND TUESDAY. MODELS CONTINUE TO SUGGEST A
MORE ORGANIZED PATTERN DEVELOPING ALOFT DURING THE MIDDLE OF THE
WEEK WITH A COLD FRONT SOMETIME LATE WEDS/EARLY THURSDAY.

TEMPERATURES WILL BE SEASONABLE AHEAD OF THE FRONT WITH HIGHS
GENERALLY IN THE LOW 80S (MID-UPPER 80S OUT WEST) AND LOWS IN THE
60S. DESPITE THE DIFFERENCE IN TIMING OF THE FRONT FROM RUN-TO-
RUN...MODELS HAVE BEEN CONSISTENT WITH THE STRENGTH OF THE
FRONT. TEMPERATURES IN THE WAKE OF THE FRONT COULD POTENTIALLY BE
10 TO 15 DEGREES COOLER THAN WHAT WE`LL HAVE DURING THE MIDDLE OF
NEXT WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              60  81  65  81  63 /  20  20  10  20  40
AUSTIN BERGSTROM INTL AIRPORT  57  80  64  80  61 /  20  20  10  20  40
NEW BRAUNFELS MUNI AIRPORT     60  82  65  80  64 /  20  20  10  20  40
BURNET MUNI AIRPORT            58  78  63  79  62 /  20  20  10  20  40
DEL RIO INTL AIRPORT           61  81  66  85  65 /  20  -   -   20  40
GEORGETOWN MUNI AIRPORT        58  79  64  79  62 /  20  20  10  20  40
HONDO MUNI AIRPORT             59  82  65  81  64 /  20  10  10  20  40
SAN MARCOS MUNI AIRPORT        59  80  64  79  63 /  20  20  10  20  40
LA GRANGE - FAYETTE REGIONAL   62  82  66  80  65 /  20  20  10  20  20
SAN ANTONIO INTL AIRPORT       60  81  64  79  64 /  20  20  10  20  40
STINSON MUNI AIRPORT           60  81  65  80  65 /  20  20  10  20  40

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

MESOSCALE/AVIATION...17
SYNOPTIC/GRIDS...04






AREA FORECAST DISCUSSION

NWS SPOKANE WA

 422 PM PDT Sat Apr 27 2013

.SYNOPSIS...
An upper level low pressure system passing through the region
tonight will bring scattered showers along the Cascade crest and
over the Central Panhandle Mountains. Another storm system is
expected Sunday night into Monday and will bring a better chance
for some rain and mountain snow along with stronger winds for
Monday afternoon. This system will usher in much cooler
temperatures for early next week. High pressure will then rebound,
bringing a warming trend for the middle to end of next week.



&&

.DISCUSSION...
Tonight: A cold front is beginning to sag into the region from the
northwest. Water vapor imagery shows a nicely defined dry slot
indicating the back edge of the front from Castlegar in BC to 50
N 160 W in the Gulf of Alaska. A fetch of Pacific moisture is
streaming eastward into the Northwest along the leading edge of
the front and is expected to sag southward with time tonight. This
moisture has generally only yielded some rain across western
Washington up to the crest of the Cascade Mountain Range. Over
eastern WA into the ID Panhandle, we have been too dry for any of
this moisture to reach the surface yet. However, LAPS data has
shown a gradual moistening of the upper atmosphere through time
today, and radar has begin to show some blips to the east and
south of Spokane. We should hold on to a fairly substantial pocket
of dry air through tonight across the basin. Strong westerly flow
across the Cascades will undoubtedly result in conditions
remaining dry east for the western two-thirds of the forecast area
(expect right along the Cascade crest). Eventually we will begin
to see some rain reaching the surface late this afternoon or early
evening. Latest HRRR model guidance suggest that measurable
rainfall will begin in the Central Panhandle Mountains around 6:00
PM or so. Gusty winds across the Wenatchee Area over into the
western portions of the basin are expected to relax this evening
as we begin to decouple a bit from the free atmosphere. I fully
anticipate our Wind Advisory to be able to come down right around
sunset today. /SVH

...BREEZY SUNDAY THEN VERY WINDY ON MONDAY...

Sunday through Monday night: Wind will be the main concern for
the next couple of days as a swift westerly flow remains parked
over the Inland Northwest, along with mostly dry and cool weather.
With a surface low over the Canadian Rockies and a surface high
on the OR coast, a stiff pressure gradient will continue into
Sunday with good mixing kicking up winds in the afternoon and
early evening. Speeds should be similar if not slightly lighter
than experienced today with lack of a frontal boundary. The NAM
and SREF want to hold on to low level moisture across southeast
Washington into the Idaho Sunday morning and given the light
upslope lift, could see light showers across the Palouse, Blue
mountains and into the Idaho panhandle. Anticipate light
orographic showers to persist into the afternoon and evening in
north Idaho. Then late Sunday night, the upper level jet stream
sinks over the region while the next in a series of weather
disturbances drops into eastern Washington. There is a chance of
precipitation, although it will be small and confined to the
orographic favored areas of the Cascade crest, the Blue mountains
and parts of north Idaho. As this features pushes through the
region, winds will steadily increase due the cold and dry air
advection. The jet 120 kt jet core will be over the region by
midday Monday. This will support stronger winds mixing to the
surface and also kicking up some blowing dust. There is also the
potential for mountain wave winds off the lee side of the
Cascades. The GFS MAV seems to have the strongest winds with this
feature, supporting the idea for the potential of high wind
highlights for a good chunk of the forecast area. The NAM MET is
slightly weaker but it still shows windy conditions across the
region. Have bumped up the winds in the forecast for Monday and
will continue to highlight the concern in the Hazardous Weather
Outlook. By Monday night, drier air filters in the region with
clearing skies and winds decrease. Dewpoints take a plunge and
drop into the 20s. In sheltered areas, there is the potential for
some rather chilly freezing temperatures by late Monday night.
/rfox.

Tues to Thu night: After a few showers and breezy conditions,
high pressure brings drier weather by mid-week. Tuesday a surface
trof lingers across N ID and the E 1/3 of WA. A secondary mid-
level shortwave slides by on 130kt+ jet. The jet curves by the
Cascades through north Oregon early, placing some unstable lapse
rates, marginal CAPE (50-200 J/kg) and LI values across NE WA and
N ID. These ingredients will be working against CIN and larger-
scale subsidence with the approaching high. The forecast focuses
the primary shower threat across Idaho in mountains in the
afternoon. Ingredients are marginal for thunder so I kept it out
for now, but I would not be surprised to see some "one-clap-
wonders". I expect locally breezy conditions to continue. However
winds should be much less as compared to the days just prior.
Tuesday night to Thursday night high pressure builds in and, for
the most part, the atmosphere stabilizes with drier, clearer
conditions. A weak impulse approaches late Thursday with a few
more clouds. The threat of precipitation will be minimal.
Temperatures remain cooler than normal on Tuesday, with more
freezing temperatures possible Wednesday morning, but value
moderate toward average by Thursday. /J. Cote`

Friday through Saturday night...The Inland Northwest will be
on the eastern edge of an upper level ridge centered off the
Pacific coast. Weather-wise, this might be the first Saturday that
the weather looks fairly uneventful. The winds do not look like
they will be much of an issue, and precipitation chances will be
limited to the higher elevations of the Idaho panhandle and the
Cascades. Well above normal temperatures are forecast for both.
Friday and Saturday. ty

&&

.AVIATION...
00Z TAFS: A cold front approaching the region from the northwest
has resulted in increasing mid and high level clouds. These clouds
will lower to between 5-8k ft this evening as the atmosphere
moistens from the top down. Pre-frontal southwesterly winds will
continue through early evening with gusts around 30-35 mph over
much of the region. These winds will likely kick up some dust
across the northern Columbia Basin, which may result in some
reduced visibilities at KMWH. We may see some showers developing
in the vicinity of KCOE and KPUW this evening, but all other TAF
sites are expected to remain dry. Models are indicating the
possibility for some low stratus developing near these TAF sites
early Sunday morning, but confidence is low as boundary layer
moisture will be lacking without much rainfall anticipated with
the cold front. Winds will increase again late Sunday morning into
the afternoon with gusts of 25-30 kts common. /EK



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        43  63  43  56  32  53 /  10  10  30  10   0  10
Coeur d`Alene  41  62  40  55  30  52 /  20  20  40  20  10  20
Pullman        41  61  43  54  29  51 /  20  20  30  20  10  20
Lewiston       50  68  48  62  38  57 /  10  10  20  10  10  20
Colville       40  67  42  58  31  58 /  10  10  30  10   0  20
Sandpoint      39  61  39  54  31  50 /  30  20  70  30  10  20
Kellogg        42  59  41  49  31  45 /  60  30  70  70  20  30
Moses Lake     47  70  46  63  33  63 /   0   0  10   0   0   0
Wenatchee      48  66  46  59  37  58 /   0  10  10   0   0   0
Omak           40  68  42  58  32  59 /   0  10  10   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Wind Advisory until 8 PM PDT this evening for Moses Lake Area-
     Upper Columbia Basin-Waterville Plateau-Wenatchee Area.

&&

$$








AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 545 PM CDT FRI APR 26 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI APR 26 2013

AT 3 PM...A WEAK COLD FRONT WAS LOCATED JUST NORTH OF THE FORECAST
AREA FROM DULUTH SOUTHEAST THROUGH THE TWIN CITIES TO SIOUX CITY
IOWA. OTHER THAN A FEW CLOUDS AND A WIND SHIFT THERE WAS NO
SENSIBLE WEATHER ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER
SOUTH ACROSS NORTHEAST IOWA...AND SOUTHWEST AND CENTRAL WISCONSIN...
THERE WAS A 850 TO 700 MB THERMAL TROUGH. THE COMBINATION OF ML
CAPES RUNNING AROUND 200 J/KG AND VERY STEEP 900 TO 800 MB LAPSE
RATES HAVE RESULTED IN SOME INSTABILITY CLOUDS DEVELOPING ACROSS
THIS AREA. THE NMM AND SPC WRF GENERATE A LINE OF SHOWERS IN THIS
REGION FROM LATE THIS AFTERNOON INTO TONIGHT. THESE MODELS ARE
ABOUT 10F TOO HIGH ON THEIR SURFACE DEW POINTS. MEANWHILE THE ARW
WHICH HAS A BETTER HANDLE OF THE SURFACE DEW POINTS SHOWS NO
PRECIPITATION AT ALL. WITH THE LATEST RAP SOUNDINGS CONTINUING TO
SHOW A VERY SHALLOW MOISTURE LAYER AROUND 800 MB...TRENDED THE
FORECAST TOWARD THE ARW FOR TONIGHT.

ON SATURDAY...THE 26.12Z AND 26.18Z MODELS ARE IN VERY GOOD
AGREEMENT THAT THE COLD FRONT WILL MOVE NORTH AS A WARM FRONT
INITIALLY DURING THE MORNING...AND THEN QUICKLY WASHES IT OUT BY
THE AFTERNOON. THE NAM/WRF GENERATES 100 TO 200 J/KG OF ML CAPE
DURING THE AFTERNOON ALONG AND NORTH OF THE INTERSTATE 90 CORRIDOR.
MEANWHILE THE GFS SHOWS VERY LITTLE INSTABILITY AT ALL. THE
NAM/WRF LOOKS TOO HIGH ON ITS SURFACE DEW POINTS...SO PREFER THE
MORE STABLE GFS. IN ADDITION...THERE IS NO SURFACE TO 850 MB
MOISTURE TRANSPORT ANYWHERE IN THE FORECAST AREA. DUE TO
THIS...KEPT THE FORECAST DRY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 345 PM CDT FRI APR 26 2013

ON SUNDAY AFTERNOON...THE 26.12Z GFS SLOWED UP ITS MOVEMENT OF
THE PRECIPITATION INTO SOUTHEAST MINNESOTA...AND IN WEST CENTRAL
AND NORTH CENTRAL WISCONSIN. THIS IS MORE IN AGREEMENT WITH THE
GEM AND ECMWF....THEREFORE...REMOVED THE PRECIPITATION CHANCES FOR
THIS TIME PERIOD.

FROM SUNDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO STRUGGLE
WITH A COLD FRONT MOVING INTO THE REGION AND THEN MOVING BACK
NORTH AS A WARM FRONT. DUE TO THESE UNCERTAINTIES...JUST WENT WITH
THE CONSALL PRECIPITATION CHANCES. WITH BOTH THE 0-3 KM AND 0-6 KM
SHEAR LESS THAN 30 KNOTS...NOT OVERLY CONCERNED ABOUT ANY SEVERE
WEATHER AT THIS TIME.

FROM TUESDAY INTO TUESDAY NIGHT...THE MODELS CONTINUE TO STRUGGLE
WITH THE SPEED OF A STRONG COLD FRONT MOVING THROUGH THE REGION.
ML CAPES AHEAD OF THIS CLIMB INTO THE 250 TO 750 J/KG RANGE. BOTH
THE 0-3 KM AND 0-6 KM SHEAR IS FAVORABLE FOR SEVERE WEATHER. HOWEVER
THERE IS A WARM LAYER BETWEEN 800 AND 700 MB WHICH MAY CAP OFF ANY
PRECIPITATION PRIOR TO THE FRONTAL PASSAGE.

IN THE WAKE OF THIS FRONT...TEMPERATURES WILL BE MUCH COLDER FROM
WEDNESDAY THROUGH FRIDAY. THE LATEST ECMWF SUGGEST HIGHS ONLY IN
THE 30S AND 40S. THE GFS IS A SLIGHTLY A BIT HIGHER. SINCE THE
MODELS HAVE BEEN SO INCONSISTENT WITH THIS SYSTEM OVER THE PAST
COUPLE OF DAYS...JUST STAYED WITH THE ALL BLEND FOR NOW.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 545 PM CDT FRI APR 26 2013

VFR CONDITIONS WITH LIGHTER WINDS ARE EXPECTED FOR THE NEXT 24
HOURS AS A TROUGH OF LOW PRESSURE CURRENTLY JUST WEST OF KRST
WEAKENS. THERE IS A STREAM OF MOISTURE AHEAD OF THIS
TROUGH...RESULTING IN VFR CUMULUS FOR THIS EVENING AND SATURDAY
AFTERNOON. LOSS OF DIURNAL HEATING AND WEAKENING PRESSURE GRADIENT
OVER THE TAF SITES WILL HELP WINDS DIMINISH BY 02Z WITH SPEEDS
LESS THAN 10 KT EXPECTED THROUGH SATURDAY. ONE CONCERN FROM
VARIOUS MODELS IS SOME MVFR OR EVEN IFR BR DEVELOPMENT BETWEEN
09-13Z...DUE TO THE DIMINISHING WIND. IN ADDITION...DEWPOINTS ARE
INCREASING NOW WITH LOSS OF HEATING...WHICH IS A POSITIVE FOR FOG
FORMATION. HOWEVER...HAVE CONTINUED TO KEEP THE BR MENTION OUT
OF THE TAFS FOR NOW GIVEN THAT SOME WIND LOOKS TO PERSIST.

&&

.HYDROLOGY...
ISSUED AT 345 PM CDT FRI APR 26 2013

TRIBUTARY STREAMS CONTINUE TO FALL FOR THE MOST PART. HIGH WATER
CONTINUES ALONG THE BLACK AND TREMPEALEAU RIVERS...WITH THE BLACK
STILL SEEING SOME IMPACTS FROM MELTING SNOW UP IN THE HEADWATER
AREAS OF CLARK/TAYLOR COUNTIES. EXPECT TO SEE SOME ADDITIONAL
RISES ALONG THE BLACK IN THE COMING DAYS DUE TO THE WARMING
TEMPERATURES.

FOR THE MISSISSIPPI RIVER...IT LOOKS TO CONTINUE RISING SLOWLY ALL
THE WAY INTO THE SECOND WEEK OF MAY. HOW HIGH IT GETS WILL DEPEND
GREATLY ON HOW MUCH RUNOFF MOVES DOWNSTREAM FROM THE SNOW COVERED
AREAS OF CENTRAL/NORTHERN MN...AND NORTHWEST WI. THE LATEST
FORECASTS ATTEMPT TO TAKE THIS SNOWMELT RUNOFF INTO ACCOUNT...BUT
MODIFICATIONS TO THE FORECAST ARE LIKELY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
HYDROLOGY...WELVAERT








AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 346 PM CDT FRI APR 26 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI APR 26 2013

AT 3 PM...A WEAK COLD FRONT WAS LOCATED JUST NORTH OF THE FORECAST
AREA FROM DULUTH SOUTHEAST THROUGH THE TWIN CITIES TO SIOUX CITY
IOWA. OTHER THAN A FEW CLOUDS AND A WIND SHIFT THERE WAS NO
SENSIBLE WEATHER ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER
SOUTH ACROSS NORTHEAST IOWA...AND SOUTHWEST AND CENTRAL WISCONSIN...
THERE WAS A 850 TO 700 MB THERMAL TROUGH. THE COMBINATION OF ML
CAPES RUNNING AROUND 200 J/KG AND VERY STEEP 900 TO 800 MB LAPSE
RATES HAVE RESULTED IN SOME INSTABILITY CLOUDS DEVELOPING ACROSS
THIS AREA. THE NMM AND SPC WRF GENERATE A LINE OF SHOWERS IN THIS
REGION FROM LATE THIS AFTERNOON INTO TONIGHT. THESE MODELS ARE
ABOUT 10F TOO HIGH ON THEIR SURFACE DEW POINTS. MEANWHILE THE ARW
WHICH HAS A BETTER HANDLE OF THE SURFACE DEW POINTS SHOWS NO
PRECIPITATION AT ALL. WITH THE LATEST RAP SOUNDINGS CONTINUING TO
SHOW A VERY SHALLOW MOISTURE LAYER AROUND 800 MB...TRENDED THE
FORECAST TOWARD THE ARW FOR TONIGHT.

ON SATURDAY...THE 26.12Z AND 26.18Z MODELS ARE IN VERY GOOD
AGREEMENT THAT THE COLD FRONT WILL MOVE NORTH AS A WARM FRONT
INITIALLY DURING THE MORNING...AND THEN QUICKLY WASHES IT OUT BY
THE AFTERNOON. THE NAM/WRF GENERATES 100 TO 200 J/KG OF ML CAPE
DURING THE AFTERNOON ALONG AND NORTH OF THE INTERSTATE 90 CORRIDOR.
MEANWHILE THE GFS SHOWS VERY LITTLE INSTABILITY AT ALL. THE
NAM/WRF LOOKS TOO HIGH ON ITS SURFACE DEW POINTS...SO PREFER THE
MORE STABLE GFS. IN ADDITION...THERE IS NO SURFACE TO 850 MB
MOISTURE TRANSPORT ANYWHERE IN THE FORECAST AREA. DUE TO
THIS...KEPT THE FORECAST DRY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 345 PM CDT FRI APR 26 2013

ON SUNDAY AFTERNOON...THE 26.12Z GFS SLOWED UP ITS MOVEMENT OF
THE PRECIPITATION INTO SOUTHEAST MINNESOTA...AND IN WEST CENTRAL
AND NORTH CENTRAL WISCONSIN. THIS IS MORE IN AGREEMENT WITH THE
GEM AND ECMWF....THEREFORE...REMOVED THE PRECIPITATION CHANCES FOR
THIS TIME PERIOD.

FROM SUNDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO STRUGGLE
WITH A COLD FRONT MOVING INTO THE REGION AND THEN MOVING BACK
NORTH AS A WARM FRONT. DUE TO THESE UNCERTAINTIES...JUST WENT WITH
THE CONSALL PRECIPITATION CHANCES. WITH BOTH THE 0-3 KM AND 0-6 KM
SHEAR LESS THAN 30 KNOTS...NOT OVERLY CONCERNED ABOUT ANY SEVERE
WEATHER AT THIS TIME.

FROM TUESDAY INTO TUESDAY NIGHT...THE MODELS CONTINUE TO STRUGGLE
WITH THE SPEED OF A STRONG COLD FRONT MOVING THROUGH THE REGION.
ML CAPES AHEAD OF THIS CLIMB INTO THE 250 TO 750 J/KG RANGE. BOTH
THE 0-3 KM AND 0-6 KM SHEAR IS FAVORABLE FOR SEVERE WEATHER. HOWEVER
THERE IS A WARM LAYER BETWEEN 800 AND 700 MB WHICH MAY CAP OFF ANY
PRECIPITATION PRIOR TO THE FRONTAL PASSAGE.

IN THE WAKE OF THIS FRONT...TEMPERATURES WILL BE MUCH COLDER FROM
WEDNESDAY THROUGH FRIDAY. THE LATEST ECMWF SUGGEST HIGHS ONLY IN
THE 30S AND 40S. THE GFS IS A SLIGHTLY A BIT HIGHER. SINCE THE
MODELS HAVE BEEN SO INCONSISTENT WITH THIS SYSTEM OVER THE PAST
COUPLE OF DAYS...JUST STAYED WITH THE ALL BLEND FOR NOW.

&&

.AVIATION...THROUGH 18Z SATURDAY
1230 PM CDT FRI APR 26 2013

MAIN AVIATION CONCERNS THROUGH PERIOD ARE WINDS THIS
AFTERNOON...THEN WEAK COLD FRONT MOVES ACROSS THE REGION THIS
EVENING. LATEST 17Z SURFACE ANALYSIS INDICATES COLD FRONT
EXTENDING FROM NORTHWEST WISCONSIN TO SOUTHWEST MINNESOTA. TIGHT
PRESSURE GRADIENT OUT AHEAD OF COLD FRONT IS PRODUCING SUSTAINED
WIND SPEEDS OF 15 TO 20 KNOTS AND GUST UP TO 29 KNOTS PER 17Z
METARS. WIND SPEEDS SHOULD REMAIN AT THESE SPEEDS THROUGH 21Z TO
22Z AT RST AND LSE TAF SITES. AS THE COLD FRONT TRACKS ACROSS THE
AREA THIS EVENING...PRESSURE GRADIENT SLACKENS AND WINDS SPEEDS
WILL BE LESS THAN 10 KNOTS THROUGH THE REST OF THE TAF PERIOD.

DUE TO DAYTIME HEATING THIS AFTERNOON OUT AHEAD OF THE COLD FRONT...
A SCATTERED DECK OF CUMULUS CLOUDS AT 4000 TO 5000 FEET WILL DEVELOP
BY 21Z AT BOTH TAF SITES. THIS DECK OF CLOUDS MAY BECOME BROKEN
AFTER 22Z FRIDAY TO 02Z SATURDAY AT LSE...WHERE BETTER MOISTURE
EXIST. HOWEVER...THE CUMULUS DECK SHOULD REMAIN IN THE VFR RANGE.
AFTER 02Z SATURDAY...VFR CONDITIONS WILL PREVAIL.


&&

.HYDROLOGY...
ISSUED AT 345 PM CDT FRI APR 26 2013

TRIBUTARY STREAMS CONTINUE TO FALL FOR THE MOST PART. HIGH WATER
CONTINUES ALONG THE BLACK AND TREMPEALEAU RIVERS...WITH THE BLACK
STILL SEEING SOME IMPACTS FROM MELTING SNOW UP IN THE HEADWATER
AREAS OF CLARK/TAYLOR COUNTIES. EXPECT TO SEE SOME ADDITIONAL
RISES ALONG THE BLACK IN THE COMING DAYS DUE TO THE WARMING
TEMPERATURES.

FOR THE MISSISSIPPI RIVER...IT LOOKS TO CONTINUE RISING SLOWLY ALL
THE WAY INTO THE SECOND WEEK OF MAY. HOW HIGH IT GETS WILL DEPEND
GREATLY ON HOW MUCH RUNOFF MOVES DOWNSTREAM FROM THE SNOW COVERED
AREAS OF CENTRAL/NORTHERN MN...AND NORTHWEST WI. THE LATEST
FORECASTS ATTEMPT TO TAKE THIS SNOWMELT RUNOFF INTO ACCOUNT...BUT
MODIFICATIONS TO THE FORECAST ARE LIKELY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ
HYDROLOGY...WELVAERT







FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE



 .SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 210 PM CDT FRI APR 26 2013

LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE WARM
ADVECTION PRECIP FROM EARLIER TODAY RACING OFF INTO SOUTHEAST ONTARIO
WHILE A WEAK FRONT IS NOW SLIDING INTO NORTHERN IOWA AND WESTERN
WISCONSIN.  THE FRONT IS RELATIVELY INACTIVE EARLY THIS AFTERNOON
EXCEPT FOR A DEVELOPING CU FIELD OVER NORTHEAST IOWA.  MEANWHILE...A
TRAILING LINE OF MID-CLOUDS IS LINGERING ACROSS NE WISCONSIN ALONG
THE TAIL END OF A SHORTWAVE MOVING ACROSS ONTARIO...WHICH IS KEEPING
SKIES PARTLY TO MOSTLY CLOUDY IN SPOTS.  TEMPERATURES HAVE WARMED
INTO THE MID 50S NORTH TO MID 60S SOUTH AS WARMER AIR INVADES THE
REGION.  AS THE FRONT SAGS INTO CENTRAL AND NE WISCONSIN LATER
TODAY...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.

TONIGHT...A WEAK FRONT WILL SAG ACROSS THE STATE FROM LA CROSSE TO
MARINETTE WHERE IT WILL STALL FOR MOST OF THE NIGHT.  RATHER BAGGY
LOW LEVEL THETAE AXIS WILL RESIDE ABOVE THE FRONTAL BOUNDARY...BUT
PROGGED SOUNDINGS DO NOT SHOW MUCH SATURATION AND DEWPOINTS MIXED
OUT TOO MUCH TODAY FOR INSTABILITY TO DEVELOP.  IN ADDITION...DO NOT THINK
WEAK FORCING ALONG THE FRONT WILL BE ENOUGH TO OVERCOME LOSS OF
HEATING AND INCREASING SUBSIDENCE ALOFT. MANY OF THE HI
RES MODELS SHOW PRECIP EXPANDING OVER NORTHEAST WISCONSIN THIS
EVENING...BUT THINK THIS WILL BE TOUGH DUE TO THE REASONS MENTIONED
ABOVE.  NORTH OF THE FRONT...WINDS WILL TURN CALM...WHICH COMBINED
WITH SNOW MELT AND CLEAR SKIES...WILL PROMOTE FOG FORMATION LATE
TONIGHT.  HAVE EXPANDED AREAS OF FOG INTO CENTRAL WISCONSIN.  LOWS
FALLING INTO THE MID 30S NORTH OF THE FRONT...AND INTO THE MID OR
UPPER 40S SOUTH OF THE FRONT.

SATURDAY...THE FRONT WILL STILL BE AROUND AT THE START OF THE
MORNING BUT WILL EVENTUALLY WASH OUT BY MIDDAY OR SO.  MOISTURE WILL
LINGER HOWEVER...AND SHOULD LEAD TO A DIURNAL CU FIELD.  SOME MODELS
SPIT OUT LIGHT QPF TOMORROW AFTERNOON...BUT THAT IS LIKELY DUE TO
DEWPOINTS REACHING INTO THE UPPER 40S.  JUDGING BY CONDITIONS
UPSTREAM...UPPER 30S TO LOW 40S DEWPOINTS ARE MORE
REASONABLE...WHICH WILL NOT BE ENOUGH TO GENERATE MUCH CAPE.  SO
THINK MODELS ARE TOO PESSIMISTIC ONCE AGAIN AND WILL GO WITH A DRY
FORECAST.  925MB TEMPS ARGUE FOR HIGHS NEAR 70...AND WILL BUMP UP
TEMPS INTO THE UPPER 60S EXCEPT NEAR LAKE MICHIGAN.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 210 PM CDT FRI APR 26 2013

THE MAIN FCST CONCERNS INCLUDE PCPN TRENDS STARTING SUNDAY NIGHT...
THEN ABOVE NORMAL TEMPS TRENDING TOWARD BELOW NORMAL CONDITIONS
AGAIN BY THE LATTER HALF OF THE NEXT WORK WEEK.

DRY AND MILD CONDITIONS ARE EXPECTED AHEAD OF THE NEXT APPROACHING
COLD FRONT ON SATURDAY NIGHT AND SUNDAY. PARTLY CLOUDY SKIES AND
MIXING THROUGH 850-800 MB SHOULD YIELD MAX TEMPS IN THE UPPER 60S
AND LOWER 70S...EXCEPT NEAR LK MICH...WHERE READINGS WILL BE IN THE
50S AND LOWER 60S.

A COLD FRONT WILL PUSH INTO THE FORECAST AREA SUNDAY NIGHT AND
MONDAY...THEN LIFT BACK TO THE NORTH AS A WARM FRONT AS SOUTH
FLOW INCREASES ON MONDAY NIGHT. SCT SHRA/ISOLD TSRA ARE ANTICIPATED
THROUGH THIS PERIOD.

THE WARMEST DAY OF THE WEEK IS EXPECTED ON TUESDAY...WITH HIGHS
IN THE 70 TO 75 RANGE OVER MOST INLAND AREAS. A COLD FRONT WILL
MOVE INTO THE WSTRN PART OF THE FA LATE TUESDAY...THEN THROUGH
THE REST OF THE CWA TUESDAY NIGHT. THIS FRONT SHOULD PROVIDE OUR
BEST BET FOR ORGANIZED THUNDERSTORM ACTIVITY DURING THE NEXT WEEK.

SIGNIFICANT DIFFERENCES DEVELOP BY WEDNESDAY AND WEDNESDAY NIGHT...
AS THE GFS TAKES MOST OF THE PCPN EAST OF THE REGION WHILE THE ECMWF
DEVELOPS A BAND OF SIGNIFICANT POST-FRONTAL PCPN IN ASSOCIATION WITH
A STG RRQ OF AN UPPER JET AND INCOMING UPPER TROF. WILL JUST CARRY
MID-RANGE POPS FOR NOW...AND SEE HOW THIS EVOLVES.

MUCH COLDER AIR WILL PUSH INTO THE AREA WEDNESDAY NIGHT...AND LINGER
INTO FRIDAY. IN ADDITION...THE DEEP UPPER TROF IS EXPECTED TO DEVELOP
INTO A CUT-OFF LOW OVER THE GREAT LAKES BY THE END OF THE WORK WEEK.
DESPITE THE CALENDAR READING EARLY MAY...CAN`T IGNORE THE POSSIBILITY
OF SOME LIGHT SNOW SHOWERS...ESPECIALLY OVER NC WI LATE WEDS NGT/
EARLY THU...AND OVER MOST OF THE FA LATE THU NGT INTO EARLY FRIDAY.
TEMPERATURES WILL RETURN TO MUCH BELOW NORMAL LEVELS.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1234 PM CDT FRI APR 26 2013

A WEAK FRONT WILL STALL ACROSS CENTRAL AND NORTHEAST
WISCONSIN THIS AFTERNOON AND WILL HANG AROUND THROUGH SATURDAY.
ISOLATED SHOWERS ARE POSSIBLE ALONG THE FRONT LATE THIS AFTERNOON
INTO EARLY THIS EVENING...BUT ODDS ARE TOO SMALL TO INCLUDE IN THE
TAFS AT THIS TIME.  HOWEVER...WITH THE FRONT DRAPED ACROSS THE
REGION...ONGOING SNOW MELT...AND WINDS TURNING CALM...FOG LOOKS LIKE
A GOOD BET ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT.
THE FOG COULD BECOME DENSE AT TIMES OVER NORTH-CENTRAL WISCONSIN.
THE FOG WILL BURN OFF BY MID-MORNING TOMORROW WHICH WILL LEAD TO
BUILDING CLOUDS BY MIDDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC







AREA FORECAST DISCUSSION...UPDATED

NWS MILWAUKEE/SULLIVAN WI

 1057 AM CDT FRI APR 26 2013

.UPDATE...CURRENT FCST FOR THE TODAY PERIOD IS GENERALLY ON
TRACK...WITH ONLY MINOR CHANGES MADE TO THE TODAY PERIOD. RADAR
MOSAIC SHOWS SCATTERED SHOWERS LEFT OVER FROM THIS MORNING IN
CENTRAL AND NORTHEAST WISCONSIN ASSOCIATED WITH A WARM FRONT
PUSHING THROUGH. ELSEWHERE...SFC CHART SHOWS THAT TEMPERATURES
HAVE ALREADY CLIMBED INTO THE MID AND UPPER 50S...WITH LNR AT
59...MSN AT 57...AND MKE AT 56 AS OF 10 AM.

TEMPERATURE TREND WAS RUNNING A BIT COOL. AS SUCH...ADJUSTED TEMPS
TO UPDATE TREND. FCST HIGHS THOUGH SHOULD BE FINE THOUGH. 925
TEMPS RANGE FROM 12-13 C GENERALLY THAT CORRESPONDS TO 65 TO 67
F...WHICH SEEM REASONABLE GIVEN THE ADEQUATE INSOLATION...DAYTIME
MIXING...AND WINDS EXPECTED TODAY. SKIES SHOULD BE PARTLY TO
MOSTLY SUNNY WITH SCT DIURNAL CU DEVELOPING.

ET

&&

.AVIATION/18Z TAFS/...VFR CONDITIONS EXPECTED THROUGH THIS EVENING
ACROSS TAF SITES. GUSTY SOUTHWEST WINDS WILL LINGER THROUGH THE
AFTERNOON...WITH GUSTS TO 27 KNOTS EXPECTED. WINDS WILL WEAKEN
THIS EVENING AND LATER TONIGHT...BECOMING LIGHT AND VARIABLE
BETWEEN 09Z AND 14Z SATURDAY. MILWAUKEE WILL STILL HAVE SOUTHWEST
WINDS ABOVE 5 KNOTS.

MVFR FOG IS EXPECTED AT MADISON...WAUKESHA AND KENOSHA BETWEEN 09Z
AND 14Z SATURDAY. VFR CONDITIONS WILL RETURN AFTER 14Z
SATURDAY...WITH LIGHT SOUTH WINDS BECOMING SOUTHEAST AT THE
EASTERN SITES BY AFTERNOON. LIGHT SOUTH WINDS WILL LINGER AT
MADISON.

WOOD

&&

.MARINE...SMALL CRAFT ADVISORY IN EFFECT UNTIL 7 PM SOUTH OF PORT
WASHINGTON...AND UNTIL 10 PM NORTH OF THERE. TIGHT PRESSURE
GRADIENT ALLOWING FOR GUSTY SOUTH WINDS...WHICH WILL PERSIST
THROUGH THE DAY ACROSS THE NEARSHORE WATERS. FREQUENT GUSTS TO 25
KNOTS AND WAVES OF 2 TO 4 FEET ARE EXPECTED SOUTH OF PORT
WASHINGTON. GUSTS TO 30 KNOTS AND WAVES OF 3 TO 5 FEET ARE
EXPECTED NORTH OF THERE...LINGERING INTO THE EARLY EVENING HOURS.
WINDS AND WAVES WILL SUBSIDE BY MIDDLE EVENING ACROSS THE AREA.

WOOD

&&

.PREV DISCUSSION... /ISSUED 338 AM CDT FRI APR 26 2013/

SHORT TERM...

TODAY AND TONIGHT. FORECAST CONFIDENCE MEDIUM.

GFS STILL SHOWING HIGHER QPF AMOUNTS AND WIDER COVERAGE THAN OTHER
MODELS WITH WARM AIR ADVECTION/SHORT WAVE-INDUCED PCPN EARLY THIS
MORNING. NOT MUCH CURRENTLY GOING ON OUT WEST...BUT IR SATELLITE
IMAGERY SHOWING AN ENHANCED BAND OF COLDER CLOUD TOPS DEVELOPING IN
REGION OF STRENGTHENING FRONTOGENETIC RESPONSE AS EASTERN DAKOTA
SHORT WAVE INTERACTS WITH AXIS OF 50-55 KT LOW-LEVEL JET AND
ASSOCIATED ISENTROPIC ADIABATIC OMEGA.

REGIONAL RADARS SHOW BLOSSOMING RETURNS WHICH ARE MAINLY
VIRGA/SPRINKLES NEAR OUR FORECAST AREA WITH SHOWERS AND ISOLATED
THUNDER FARTHER NORTH ON NOSE OF LLJ. LACK OF MEASURING GROUND
TRUTH REFLECTING THE DRY AIR BELOW 6-7K FT ON THE 00Z MSP RAOB AND
CURRENT RAP FORECAST SOUNDINGS FOR THE REGION. NORTHERN CWA WILL BE
BRUSHED BY LOWER CONDENSATION PRESSURE DEFICITS...BUT THESE ARE
ABOVE 700 MB ON 295K SURFACE WHILE STRONGER ISENTROPIC UPGLIDE IS
LOWER IN REGION OF 100-200 MB PRESSURE DEFICITS...EVEN ON THE WETTER
GFS. WILL LIMIT TO SPRINKLES ACROSS THE FAR NORTHERN CWA AFTER 09Z.

SURFACE TROUGH LAYS OUT JUST TO THE NORTHWEST OF FORECAST AREA THIS
AFTERNOON. RAP SOUNDINGS SHOW CAPE RISING AS HIGH AS 100-200 J/KG
WITH LITTLE CIN THIS AFTERNOON...THOUGH PREDICATED ON DEW POINTS IN
THE MID 50S. CAPE NON-EXISTENT WITH MORE REASONABLE AND DRIER
SURFACE DEW POINTS ON NAM AND GFS SOUNDINGS...BUT PERSISTENT
LOW-LEVEL FRONTOGENESIS AND SURFACE MOISTURE CONVERGENCE ALONG
TROUGH AXIS REQUIRES A SLIGHT CHANCE IN THE NW CWA THIS
AFTERNOON...ENDING AS SURFACE RIDGE NOSES IN FROM THE SOUTHEAST
WIPING OUT WEAK TROUGH.

HIGHS RISE INTO THE MID TO UPPER 60S INLAND...THOUGH LATE IN THE DAY
AROUND 60 FAR EAST ALONG THE LAKE WITH GUSTY SOUTHWEST WINDS FINALLY
ENDING COOLING ONSHORE COMPONENT OF SOUTH WINDS EARLY IN THE DAY.

QUIET TONIGHT AS SURFACE RIDGE SETTLES OVER REGION...WITH LOWS IN
THE 40S...EVEN ALONG THE LAKE AS SW WINDS CONTINUE OVERNIGHT THOUGH
WEAKENING WINDS TOWARD MORNING MAY TURN WINDS ASHORE BEFORE DAYBREAK.

SATURDAY THROUGH SUNDAY...FORECAST CONFIDENCE HIGH.

A WEAK UPPER LOW WILL TRACK ACROSS MISSOURI AND ILLINOIS OVER THE
WEEKEND. A HIGH PRESSURE RIDGE WILL SETTLE INTO SOUTHERN WI...AND
WARMER AIR WILL SLOWLY BUT SURELY STREAM INTO THE AREA UNDER MOSTLY
CLEAR SKIES. IT LOOKS LIKE A PLEASANT WEEKEND IS IN STORE WITH HIGHS
REACHING AROUND 70 INLAND FROM THE LAKE BY SUNDAY. THE WEAK PRESSURE
GRADIENT WILL ALLOW A LAKE BREEZE TO DEVELOP EACH DAY...KEEPING
LAKESHORE AREAS IN THE UPPER 50S/LOWER 60S.

LONG TERM...

SUNDAY NIGHT THROUGH MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

A SURFACE AND UPPER LEVEL TROUGH WILL SWING ACROSS THE UPPER MIDWEST
SUNDAY NIGHT AND WEAKEN/STALL OVER CENTRAL/SOUTHERN WI THROUGH
MONDAY. THERE IS DEBATE BETWEEN MODELS ABOUT WHETHER THAT FRONT WILL
MOVE ALL THE WAY THROUGH SOUTHEAST WI OR REMAIN OVER CENTRAL WI.
THERE IS A CHANCE THAT ANOTHER SHORTWAVE WILL MOVE INTO SOUTHERN WI
ALONG A STALLED 850MB BAROCLINIC ZONE AND COMBINE WITH ISENTROPIC
LIFT TO PRODUCE SHOWERS OVER SOUTHERN WI LATE SUN NIGHT THROUGH MON
NIGHT. MODEL SOUNDINGS SHOW SURFACE BASED CAPE OF ALMOST 500
J/KG...SO KEPT MENTION OF THUNDER CHANCES.

TEMPERATURES WILL BE ON THE RISE FOR MONDAY AHEAD OF THAT UPPER
TROUGH...BUT AND SHOWERS/THUNDERSTORMS THAT DEVELOP COULD HINDER THE
WARMEST TEMPS. GOOD CHANCE FOR 70 IN MOST PLACES INLAND FROM THE
LAKE.

TUESDAY THROUGH THURSDAY...FORECAST CONFIDENCE LOW TO MEDIUM.

TEMPERATURES ARE EXPECTED TO RISE INTO AT LEAST THE MID 70S ON
TUESDAY AHEAD OF AN APPROACHING COLD FRONT.

EVENTUALLY A COLD FRONT WILL MOVE ACROSS SOUTHEAST WI WITH THE
PASSAGE OF A DEEP UPPER TROUGH. TIMING OF THIS FRONT IS VERY
UNCERTAIN. THE GFS BRINGS IT THROUGH MIDDAY WEDNESDAY...THE CANADIAN
MODEL WEDNESDAY AFTERNOON...AND THE ECMWF NOT UNTIL THURSDAY
MORNING. THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS AHEAD
OF AND ALONG THE FRONT...AND A CHANCE FOR RAIN SHOWERS AND MAYBE A
FEW SNOW SHOWERS JUST BEHIND THE FRONT.

FRIDAY AND BEYOND...FORECAST CONFIDENCE MEDIUM.

MODELS ALL CLOSE OFF THE 500MB TROUGH AND STALL IT OVER THE WESTERN
GREAT LAKES REGION...KEEPING CHANCES FOR RAIN SHOWERS OR MAYBE EVEN
SNOW SHOWERS OVER SOUTHERN WI INTO NEXT WEEKEND.

AVIATION/12Z TAFS/...

VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS ANY LIGHT
PRECIPITATION WITH SHORT WAVE CROSSING REGION AND STALLING SURFACE
TROUGH EXPECTED TO REMAIN NORTH OF TAF SITES. GUSTY SW WINDS INTO
THIS EVENING. LOW LEVEL MOISTURE THAT COULD BRING MVFR CLOUDS IN
TONIGHT APPEARS TO BE PREDICATED ON OVERLY HIGH DEW POINTS. STILL A
LATE NIGHT TURN OF THE SW WINDS TO SOUTH OR SOUTH-SOUTHEAST NEAR THE
LAKE COULD BRING FOG TO EASTERN TAF SITES.

MARINE...SOUTH WINDS WILL CONTINUE TO PICK UP THROUGH THE EARLY
MORNING HOURS AHEAD OF LOW PRESSURE CROSSING SRN CANADA...THEN SHIFT
SOUTHWEST THIS AFTERNOON AS SURFACE TROUGH STALLS ACROSS
STATE...DIMINISHING TONIGHT AS RIDGE OF SURFACE HIGH PRESSURE NOSES
OVER THE SOUTHERN PORTION OF THE LAKE. WILL KEEP CURRENT ADVISORY AS
IS FOR SOUTHERN THREE ZONES...BUT EXTEND NORTHERN ZONE UNTIL 03Z TO
ALLOW HIGHER WAVES THERE TO SUBSIDE.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ644>646.

     SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ643.

&&

$$

UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...REM
SATURDAY THROUGH THURSDAY...MRC







AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

 338 AM CDT FRI APR 26 2013

.SHORT TERM...

TODAY AND TONIGHT. FORECAST CONFIDENCE MEDIUM.

GFS STILL SHOWING HIGHER QPF AMOUNTS AND WIDER COVERAGE THAN OTHER
MODELS WITH WARM AIR ADVECTION/SHORT WAVE-INDUCED PCPN EARLY THIS
MORNING. NOT MUCH CURRENTLY GOING ON OUT WEST...BUT IR SATELLITE
IMAGERY SHOWING AN ENHANCED BAND OF COLDER CLOUD TOPS DEVELOPING IN
REGION OF STRENGTHENING FRONTOGENETIC RESPONSE AS EASTERN DAKOTA
SHORT WAVE INTERACTS WITH AXIS OF 50-55 KT LOW-LEVEL JET AND
ASSOCIATED ISENTROPIC ADIABATIC OMEGA.

REGIONAL RADARS SHOW BLOSSOMING RETURNS WHICH ARE MAINLY
VIRGA/SPRINKLES NEAR OUR FORECAST AREA WITH SHOWERS AND ISOLATED
THUNDER FARTHER NORTH ON NOSE OF LLJ. LACK OF MEASURING GROUND
TRUTH REFLECTING THE DRY AIR BELOW 6-7K FT ON THE 00Z MSP RAOB AND
CURRENT RAP FORECAST SOUNDINGS FOR THE REGION. NORTHERN CWA WILL BE
BRUSHED BY LOWER CONDENSATION PRESSURE DEFICITS...BUT THESE ARE
ABOVE 700 MB ON 295K SURFACE WHILE STRONGER ISENTROPIC UPGLIDE IS
LOWER IN REGION OF 100-200 MB PRESSURE DEFICITS...EVEN ON THE WETTER
GFS. WILL LIMIT TO SPRINKLES ACROSS THE FAR NORTHERN CWA AFTER 09Z.

SURFACE TROUGH LAYS OUT JUST TO THE NORTHWEST OF FORECAST AREA THIS
AFTERNOON. RAP SOUNDINGS SHOW CAPE RISING AS HIGH AS 100-200 J/KG
WITH LITTLE CIN THIS AFTERNOON...THOUGH PREDICATED ON DEW POINTS IN
THE MID 50S. CAPE NON-EXISTENT WITH MORE REASONABLE AND DRIER
SURFACE DEW POINTS ON NAM AND GFS SOUNDINGS...BUT PERSISTENT
LOW-LEVEL FRONTOGENESIS AND SURFACE MOISTURE CONVERGENCE ALONG
TROUGH AXIS REQUIRES A SLIGHT CHANCE IN THE NW CWA THIS
AFTERNOON...ENDING AS SURFACE RIDGE NOSES IN FROM THE SOUTHEAST
WIPING OUT WEAK TROUGH.

HIGHS RISE INTO THE MID TO UPPER 60S INLAND...THOUGH LATE IN THE DAY
AROUND 60 FAR EAST ALONG THE LAKE WITH GUSTY SOUTHWEST WINDS FINALLY
ENDING COOLING ONSHORE COMPONENT OF SOUTH WINDS EARLY IN THE DAY.

QUIET TONIGHT AS SURFACE RIDGE SETTLES OVER REGION...WITH LOWS IN
THE 40S...EVEN ALONG THE LAKE AS SW WINDS CONTINUE OVERNIGHT THOUGH
WEAKENING WINDS TOWARD MORNING MAY TURN WINDS ASHORE BEFORE DAYBREAK.

SATURDAY THROUGH SUNDAY...FORECAST CONFIDENCE HIGH.

A WEAK UPPER LOW WILL TRACK ACROSS MISSOURI AND ILLINOIS OVER THE
WEEKEND. A HIGH PRESSURE RIDGE WILL SETTLE INTO SOUTHERN WI...AND
WARMER AIR WILL SLOWLY BUT SURELY STREAM INTO THE AREA UNDER MOSTLY
CLEAR SKIES. IT LOOKS LIKE A PLEASANT WEEKEND IS IN STORE WITH HIGHS
REACHING AROUND 70 INLAND FROM THE LAKE BY SUNDAY. THE WEAK PRESSURE
GRADIENT WILL ALLOW A LAKE BREEZE TO DEVELOP EACH DAY...KEEPING
LAKESHORE AREAS IN THE UPPER 50S/LOWER 60S.

.LONG TERM...

SUNDAY NIGHT THROUGH MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

A SURFACE AND UPPER LEVEL TROUGH WILL SWING ACROSS THE UPPER MIDWEST
SUNDAY NIGHT AND WEAKEN/STALL OVER CENTRAL/SOUTHERN WI THROUGH
MONDAY. THERE IS DEBATE BETWEEN MODELS ABOUT WHETHER THAT FRONT WILL
MOVE ALL THE WAY THROUGH SOUTHEAST WI OR REMAIN OVER CENTRAL WI.
THERE IS A CHANCE THAT ANOTHER SHORTWAVE WILL MOVE INTO SOUTHERN WI
ALONG A STALLED 850MB BAROCLINIC ZONE AND COMBINE WITH ISENTROPIC
LIFT TO PRODUCE SHOWERS OVER SOUTHERN WI LATE SUN NIGHT THROUGH MON
NIGHT. MODEL SOUNDINGS SHOW SURFACE BASED CAPE OF ALMOST 500
J/KG...SO KEPT MENTION OF THUNDER CHANCES.

TEMPERATURES WILL BE ON THE RISE FOR MONDAY AHEAD OF THAT UPPER
TROUGH...BUT AND SHOWERS/THUNDERSTORMS THAT DEVELOP COULD HINDER THE
WARMEST TEMPS. GOOD CHANCE FOR 70 IN MOST PLACES INLAND FROM THE
LAKE.

TUESDAY THROUGH THURSDAY...FORECAST CONFIDENCE LOW TO MEDIUM.

TEMPERATURES ARE EXPECTED TO RISE INTO AT LEAST THE MID 70S ON
TUESDAY AHEAD OF AN APPROACHING COLD FRONT.

EVENTUALLY A COLD FRONT WILL MOVE ACROSS SOUTHEAST WI WITH THE
PASSAGE OF A DEEP UPPER TROUGH. TIMING OF THIS FRONT IS VERY
UNCERTAIN. THE GFS BRINGS IT THROUGH MIDDAY WEDNESDAY...THE CANADIAN
MODEL WEDNESDAY AFTERNOON...AND THE ECMWF NOT UNTIL THURSDAY
MORNING. THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS AHEAD
OF AND ALONG THE FRONT...AND A CHANCE FOR RAIN SHOWERS AND MAYBE A
FEW SNOW SHOWERS JUST BEHIND THE FRONT.

FRIDAY AND BEYOND...FORECAST CONFIDENCE MEDIUM.

MODELS ALL CLOSE OFF THE 500MB TROUGH AND STALL IT OVER THE WESTERN
GREAT LAKES REGION...KEEPING CHANCES FOR RAIN SHOWERS OR MAYBE EVEN
SNOW SHOWERS OVER SOUTHERN WI INTO NEXT WEEKEND.

&&

.AVIATION/12Z TAFS/...

VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS ANY LIGHT
PRECIPITATION WITH SHORT WAVE CROSSING REGION AND STALLING SURFACE
TROUGH EXPECTED TO REMAIN NORTH OF TAF SITES. GUSTY SW WINDS INTO
THIS EVENING. LOW LEVEL MOISTURE THAT COULD BRING MVFR CLOUDS IN
TONIGHT APPEARS TO BE PREDICATED ON OVERLY HIGH DEW POINTS. STILL A
LATE NIGHT TURN OF THE SW WINDS TO SOUTH OR SOUTH-SOUTHEAST NEAR THE
LAKE COULD BRING FOG TO EASTERN TAF SITES.

&&

.MARINE...SOUTH WINDS WILL CONTINUE TO PICK UP THROUGH THE EARLY
MORNING HOURS AHEAD OF LOW PRESSURE CROSSING SRN CANADA...THEN SHIFT
SOUTHWEST THIS AFTERNOON AS SURFACE TROUGH STALLS ACROSS
STATE...DIMINISHING TONIGHT AS RIDGE OF SURFACE HIGH PRESSURE NOSES
OVER THE SOUTHERN PORTION OF THE LAKE. WILL KEEP CURRENT ADVISORY AS
IS FOR SOUTHERN THREE ZONES...BUT EXTEND NORTHERN ZONE UNTIL 03Z TO
ALLOW HIGHER WAVES THERE TO SUBSIDE.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS
     EVENING FOR LMZ644>646.

     SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM CDT THIS
     EVENING FOR LMZ643.

&&

$$

TODAY/TONIGHT AND AVIATION/MARINE...REM
SATURDAY THROUGH THURSDAY...MRC








AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 153 AM EDT SUN APR 28 2013

.SYNOPSIS...
LOW PRESSURE AND A COLD FRONT CONTINUE TO SLOWLY MARCH TOWARD THE
REGION FROM THE SOUTHERN PLAINS AND WILL MOVE THROUGH THE AREA
MONDAY NIGHT. THIS WILL RESULT IN INCREASING SHOWERS THROUGH
MONDAY NIGHT. THE PATTERN WILL REMAIN ACTIVE THROUGH THE WEEK WITH
CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
LATEST RAP MODEL INDICATING WEAK ISENTROPIC LIFT WITH MOISTURE
CONVERGENCE FOCUS ACROSS NORTHERN MIDLANDS/PIEDMONT. UPPER RIDGE
HOLDING ACROSS SOUTHERN MIDLANDS.  USED SREF POP GUIDANCE AND CUT
POPS BACK SIGNIFICANTLY ACROSS THE SOUTH FOR THE NEXT FEW HOURS
WHERE FORCING WEAK.

SHOWERS SHOULD INCREASE LATE AS ISENTROPIC ASCENT IMPROVES OVER
THE AREA. BY DAYBREAK SUNDAY EXPECT LIKELY SHOWERS ALONG AND NORTH
OF I-20 WITH HIGH CHANCE POPS SOUTH OF I-20. WITH EAST WINDS
PUSHING ADDITIONAL MOISTURE INTO THE AREA SHOWER INTENSITY WILL
BEGIN INCREASING BY DAYBREAK WITH MOST LOCATIONS SEEING UP TO ONE
QUARTER OF AN INCH. WITH THE EXTENSIVE CLOUDS TEMPERATURES
OVERNIGHT WILL GENERALLY BE IN THE MIDDLE 50S.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SUNDAY AND SUNDAY NIGHT...LOW PRESSURE WILL BE TRACKING FROM THE
CENTRAL MS VALLEY IN THE MORNING TO THE OHIO VALLEY MONDAY NIGHT.
THE COLD FRONT WILL CONTINUE MOVING INTO THE REGION AND WITH
SOUTHEAST WINDS THE CONFIDENCE IN SHOWERS ACROSS THE AREA IS HIGH.
HAVE INCREASED POPS FOR SUNDAY AND SUNDAY NIGHT AS WELL AS
RAINFALL AMOUNTS...WHILE LOWERING TEMPERATURES A COUPLE OF
DEGREES. RAINFALL AMOUNTS WILL BE GREATEST ACROSS THE WESTERN
MIDLANDS...DUE TO PROXIMITY TO THE FRONT...HOWEVER MOST LOCATIONS
WILL SEE BETWEEN ONE HALF AND ONE INCH OF RAINFALL THROUGH MONDAY
DAYBREAK. TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 70S FOR
DAYTIME HIGHS WITH OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

MONDAY AND MONDAY NIGHT...COLD FRONT WILL PUSH THROUGH THE
FORECAST AREA MONDAY AFTERNOON WITH SHOWERS TAPERING OFF BEHIND
THE FRONT MONDAY EVENING. ALTHOUGH THERE IS LIMITED INSTABILITY
WITH FORCING FROM THE FRONT THERE IS SOME POTENTIAL FOR THUNDER SO
HAVE REMAINED WITH SHOWERS AND ISOLATED THUNDERSTORMS. SKIES WILL
BEGIN TO SLOWLY CLEAR MONDAY NIGHT...HOWEVER WITH GENERAL
SOUTHERLY FLOW EXPECT PARTLY TO MOSTLY CLOUDY SKIES TO PERSIST
THROUGH MONDAY NIGHT. DAYTIME TEMPERATURES WILL BE IN THE LOWER TO
MIDDLE 70S WITH LOWS MONDAY NIGHT IN THE MIDDLE 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
DIFFERENCES IN TIMING APPEARING ON FRIDAY. THE PATTERN WILL REMAIN
ACTIVE THROUGH THE PERIOD WITH AN OMEGA BLOCK DEVELOPING DURING
THE LATTER HALF OF THE WEEK. THIS WILL RESULT IN SLOW PROGRESSION
OF THE SYSTEMS AND A DEEP UPPER LOW EXPECTED TO MOVE INTO THE
CENTRAL PLAINS BY NEXT FRIDAY. AT THE SURFACE WITH A LOW IN THE
MID MS VALLEY AND A HIGH OVER NEW ENGLAND A WEDGE PATTERN WILL
DEVELOP OVER THE FORECAST AREA. WITH CONSISTENCY IN THE MODELS
OVER THE PAST COUPLE OF RUNS HAVE TRENDED THE FORECAST TO THE
WEDGE WITH INCREASING CLOUDS AND LOWERED TEMPERATURES FOR THURSDAY
ONWARD. BLOCKING PATTERN WILL REMAIN IN TACT THROUGH THE END OF
THE LONG TERM KEEPING THE AREA UNDER THE INFLUENCE OF THE WEDGE.
TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL ON TUESDAY
THEN COOLER THAN NORMAL FOR WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION /06Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS CURRENTLY OBSERVED ACROSS THE CWA
OVERNIGHT...HOWEVER CONDITIONS WILL GRADUALLY DETERIORATE DURING THE
TAF PERIOD. 88D REGIONAL COMPOSITE SHOWS AN AREA OF SHOWERS AND
THUNDERSTORMS ACROSS NRN/CNTRL GA THAT CONTINUE TO MOVE NORTHEAST
TOWARD THE CWA. GUIDANCE ALONG WITH WRF INDICATE THAT PRECIPITATION
WILL REACH THE TAF SITES BETWEEN 12Z AND 14Z. MOISTURE FLUX AND
ISENTROPIC LIFT INCREASE THROUGH THE DAY INTO THE REMAINDER OF THE
TAF PERIOD. GUIDANCE IS IN GOOD AGREEMENT WITH GRADUALLY LOWERING
CEILINGS THROUGH THE DAY AND EVENING HOURS AND EXPECT AT LEAST MVFR
CONDITIONS FROM MIDDAY THROUGH THE REMAINDER OF THE PERIOD. DID NOT
GO QUITE AS LOW AS SOME OF THE GUIDANCE FOR SUNDAY EVENING
INDICATING THE POTENTIAL FOR IFR CONDITIONS. HAVE DECIDED TO
INTRODUCE SHOWERS THIS MORNING BETWEEN 12Z AND 14Z WITH A TEMPO
GROUP...THEN KEPT A MENTION OF SHOWERS WITH GRADUALLY LOWERING
CEILINGS ALONG 4 TO 5 MILES VSBYS TO GIVE MVFR CONDITIONS FOR THE
REMAINDER OF THE TAF PERIOD. EXPECT WINDS TO VEER SOME THROUGH THE
PERIOD FROM E/ESE TO MORE SE THROUGH THE PERIOD. WIND SPEEDS WILL
AVERAGE FROM 4 TO 8 KNOTS.

EXTENDED AVIATION OUTLOOK...RAINFALL AND CEILING/VSBY RESTRICTIONS
EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. RESTRICTIONS ALSO
POSSIBLE IN SHOWERS TUESDAY AND TUESDAY NIGHT.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$






AREA FORECAST DISCUSSION

NWS LINCOLN IL

 300 AM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN MO
LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND STL.
00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS VALLEY
AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION EAST
OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE TO
PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX OUT
OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

.LONG TERM...WEDNESDAY THROUGH SUNDAY.
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER WAVE
MOVING THROUGH THE GREATLAKES TUESDAY NIGHT DRAGS A FRONT INTO THE
MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS PROGGED TO
DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE SOUTHERN PLAINS.
THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER VALLEY FROM WED NIGHT
INTO THE WEEKEND WITH SCATTERED PCPN ALONG THE SYSTEM. MODELS HAVE
BECOME A LITTLE MORE CONSISTANT AND IN AGREEMENT WITH THIS
SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF INTO THE PLAINS AND
PCPN IN THE MS VALLEY. BY THE WEEKEND...THE SYSTEM STARTS TO MOVE
OUT...HOWEVER THE TIMING ON THIS WILL STILL NEED TO BE WATCHED.
TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT END OF WEEK IS COOLER
THEN THE BEGINNING OF THE WEEK. WENT WITH CHC POPS AS DETAILS ON THE
EXACT POSITION OF THE FRONT AND UPPER SYSTEM STILL A LITTLE
UNCERTAIN.

GOETSCH
&&

.AVIATION...
ISSUED 1148 PM CDT SAT APR 27 2013

A COMPLEX...SLOW MOVING...UPPER LEVEL DISTURBANCE...AND ITS
ASSOCIATED SURFACE FEATURES...WILL IMPACT THE CENTRAL ILLINOIS
TERMINALS THROUGH MUCH OF THE 06Z TAF VALID TIME. THE RAINFALL
ASSOCIATED WITH THIS SYSTEM WILL BE MOST WIDESPREAD FOR THE NEXT
FEW HOURS...BEFORE GRADUALLY TAPERING OFF FROM WEST TO EAST SUNDAY
MORNING. WIDESPREAD IFR/LIFR CONDITIONS ARE ANTICIPATED FOR THE
REST OF THE NIGHT INTO SUNDAY MORNING...WITH ONLY A GRADUAL
IMPROVEMENT TO MVFR EXPECTED AFTER SUNRISE SUNDAY. FURTHER
IMPROVEMENT TO VFR SHOULD HOLD OFF UNTIL SUNDAY EVENING. LIGHT/VARIABLE
WINDS SHOULD PREVAIL THROUGH MIDDAY SUNDAY...BECOMING MORE STEADY
OUT OF THE WEST SUNDAY AFTERNOON AS THE SYSTEM PULLS AWAY.

BAK
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS DODGE CITY KS

 403 AM CDT SUN APR 28 2013


.SYNOPSIS...
ISSUED AT 400 AM CDT SUN APR 28 2013

SPLIT FLOW WAS IN PLACE ACROSS NORTH AMERICA WITH THE MAIN JET
ENERGY MOVING ACROSS WESTERN KANSAS AND THE PACIFIC NORTHWEST
REGION. ANOTHER UPPER JET AXIS WAS MOVING ACROSS MEXICO AND THE
SOUTHERN UNITED STATES. THE SYNOPTIC SCALE UPPER TROUGH WAS
POSITIONED ACROSS IOWA AND MISSOURI, WITH THE 850 MB EXTENDING
FARTHER SOUTH ACROSS THE SOUTHERN MISSISSIPPI VALLEY BASED ON THE 00
UTC SUBJECTIVE ANALYSIS. FARTHER WEST, A LARGE THERMAL GRADIENT
EXISTED ACROSS KANSAS INTO THE CENTRAL AND SOUTHERN ROCKIES AS 850
MB TEMPERATURES WERE AROUND 20 DEGREES C FROM RAP TO LBF, DDC AND
AMA. SURFACE TEMPERATURES ACROSS WESTERN KANSAS REMAINED MILD
THROUGH THE OVERNIGHT, RANGING FROM THE UPPER 40`S TO LOW 50`S
THROUGH AROUND 2 AM.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE MODELS DEVELOP A DRYLINE SHIFTING ACROSS THE AREA LATER TODAY
AS WEAK VERTICAL MIXING DEVELOPS. HOWEVER, LIGHT BOUNDARY LAYER
WINDS ARE IN PLACE AND LITTLE IF ANY GUSTING SEEMS POSSIBLE. THE
FULL AVAILABLE LATE APRIL INSOLATION WILL HELP TEMPERATURES SOAR IN
THE LATE MORNING AND EARLY AFTERNOON. MODELS ACROSS THE BOARD
FORECAST HIGHS IN THE MID TO UPPER 80`S FOR THIS AFTERNOON. THERE
DOES APPEAR TO BE A RAPID INCREASE IN SURFACE BASED CAPE ACROSS
CENTRAL KANSAS DURING THE LATE AFTERNOON. HOWEVER THE MODELS WORK
DRIER AIR FARTHER EAST INTO CENTRAL KANSAS IN THE AFTERNOON,
RELEGATING THE BEST SURFACE BASED CONVECTIVE AVAILABLE ENERGY
FARTHER EAST ACROSS EASTERN KANSAS. WITHOUT ANY UPPER SUPPORT, AND
LIMITED TO NONEXISTENT SBCAPE, EVEN ISOLATED STORMS DO NOT LOOK
LIKELY LATER TODAY.

WITH EXPECTED GOOD RADIATIONAL COOLING AND A RETREATING DRYLINE,
ANOTHER MILD NIGHT CAN BE EXPECTED. LOWS WILL REACH THE 40`S OVER
MOST OF SOUTHWEST KANSAS, TO LOW 50`S OVER THE CENTRAL SECTIONS.



.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE LONG TERM FORECAST FOR THE MIDDLE AND LATTER PORTION OF THE WEEK
IS FRAUGHT WITH CHALLENGES AS A DEEP TROUGH DEVELOPS AND A CLOSED
LOW FORMS OUT OF THE TROUGH...EVENTUALLY BECOMING CUT OFF FROM THE
MAIN POLAR JET STREAM FLOW. PRIOR TO THE STORM SYSTEM
DEVELOPMENT...TEMPERATURES WILL SOAR INTO THE UPPER 80S TO NEAR 90
BOTH MONDAY AND TUESDAY. A LEAD SHORTWAVE MOVING EAST ACROSS THE
DAKOTAS MONDAY WILL PUSH A SUBTLE FRONTAL BOUNDARY SOUTHWARD WHICH
COULD PREVENT AREAS NORTH OF HIGHWAY 96 FROM WARMING WELL INTO THE
80S LIKE THE SOUTHERN COUNTIES.  WILL BE HEDGING COOLER IN THE
FORECAST FOR THIS REASON UP NORTH...ESPECIALLY WAKEENEY TO HAYS. ON
TUESDAY...THE ECMWF SHOWS A 992MB SURFACE LOW OVER SOUTHEASTERN
COLORADO WITH A DRYLINE TAKING SHAPE EAST OF THE LOW. THE LEAD
FRONTAL BOUNDARY WILL LIKELY PUSH NORTH LATE MONDAY NIGHT INTO EARLY
TUESDAY BEFORE MOVING BACK SOUTH DURING THE DAY TUESDAY.
AGAIN...THIS WILL LEAD TO QUITE THE CHALLENGE IN HIGH TEMPERATURE
FORECAST. FEEL PRETTY CONFIDENT, THOUGH, THAT SOME 90-92 DEGREE
TEMPERATURES WILL BE FOUND SOUTHWEST OF A JOHNSON TO ASHLAND LINE.

EVEN THOUGH THERE ARE SOME 15-20 POPS IN THE FORECAST UP IN CENTRAL
KANSAS (ELLIS-RUSH COUNTIES) LATE IN THE DAY TUESDAY...THE FEELING
IS THAT CONVECTION WILL HOLD OFF UNTIL TUESDAY EVENING AND
ESPECIALLY DURING THE NIGHT. ADVANCE OF 58 TO 61F DEWPOINTS INTO
SOUTH CENTRAL AND CENTRAL KANSAS AND VERY WARM SURFACE TEMPERATURES
WILL LEAD TO 2000 TO 2500 J/KG OF CAPE TUESDAY EVENING. THE PROBLEM
IS THAT THE 800-700MB LAYER WILL BE EXTREMELY WARM LIKELY PREVENTING
SURFACE BASED CONVECTION ON THE DRYLINE SOUTH OF THE FRONT. THE MOST
LIKELY SCENARIO IS CONVECTION FORMING AT THE NOSE OF A DEVELOPING
LOW LEVEL JUST JUST AFTER SUNSET...AND THIS IS WHEN POPS WILL
INCREASE IN THE FORECAST TO 30 TO 40 PERCENT...ESPECIALLY ALONG AND
NORTH OF HIGHWAY 96.

SOMETIME AFTER MIDNIGHT TUESDAY NIGHT...THE TRUE COLD AIR WILL BE
CHARGING SOUTH THROUGH NEBRASKA AND INTO KANSAS AS THE DEEP UPPER
TROUGH APPROACHES. TEMPERATURES IN THE 50S AND LOWER 60S WILL BE
COMMON OVERNIGHT AHEAD OF THE FRONT. THE QUESTION IS TIMING AND WILL
HAVE A HUGE IMPACT ON DAYTIME TEMPERATURES WEDNESDAY ACROSS
SOUTHWEST AND SOUTH CENTRAL KANSAS. AT THIS TIME...THE BEST FORECAST
IS A FRONTAL PASSAGE SOMETIME EARLY TO MID-MORNING A FEW HOURS AFTER
SUNRISE WHEREBY THERE COULD BE A BRIEF, BUT DECENT WARM-UP BEFORE
THE RUG IS PULLED UNDERNEATH US IN THE TEMPERATURE DEPARTMENT...AKIN
TO WHAT WE SAW A COUPLE OF TIMES IN APRIL WITH TREMENDOUS COLD AIR
ADVECTION ON THE ORDER OF 20 TO 30 DEGREE FALL IN TEMPERATURE OVER
THE SPAN OF JUST A FEW HOURS. THE OFFICIAL TEMPERATURE FORECAST WILL
TRY TO REFLECT A FAIRLY ROBUST DIURNAL FALL ON WEDNESDAY ACROSS MUCH
OF THE AREA.  RAIN SHOWERS WILL BE LIKELY ESPECIALLY ACROSS CENTRAL
AND SOUTH-CENTRAL KANSAS WITH A FEW EMBEDDED THUNDERSTORMS.

FRONTOGENESIS IN THE 800-700MB LAYER WILL BE STRENGTHENING LATE IN
THE DAY WEDNESDAY AND WEDNESDAY NIGHT ACROSS WESTERN KANSAS WITH THE
THERMODYNAMIC PROFILE RAPIDLY COOLING TO THE POINT THAT FROZEN
PRECIPITATION WILL ENTER THE PICTURE. THERE WILL LIKELY BE A NARROW
CORRIDOR OF SLEET DEVELOPING LATE WEDNESDAY ACROSS FAR WEST-CENTRAL
KANSAS BUT QUICKLY CHANGING TO WET SNOW AS SURFACE TEMPERATURES
CONTINUE TO FALL THROUGH THE LOWER 30S. AFTER WEDNESDAY
NIGHT...THERE IS CONSIDERABLE DIVERGENCE IN VARIOUS MODEL SOLUTIONS
REGARDING THE DEVELOPMENT OF THE MID LEVEL CYCLONE.  THE LATEST
ECMWF MODEL IS NOW BACK TO A MORE PROGRESSIVE SCENARIO RESULTING IN
THE LOW CLOSING OFF A BIT FARTHER EAST THAN YESTERDAY`S 12Z RUN. THE
LATEST 00Z VERSION OF THE CANADIAN GEM, ON THE OTHER HAND, HAS A
MUCH MORE FAVORABLE SCENARIO FOR LONGER-DURATION PRECIPITATION EVENT
AFFECTING CENTRAL AND SOUTH-CENTRAL KANSAS THURSDAY AND FRIDAY.
THIS STILL SEEMS LIKE AN OUTLIER SCENARIO SO POPS ON THURSDAY NIGHT
AND FRIDAY WILL BE IN THE SLIGHT CHANCE RANGE AND ONLY ACROSS THE
EASTERN COUNTIES (CENTRAL AND SOUTH-CENTRAL KANSAS).

A HISTORICAL NOTE OF REFERENCE REGARDING LATE-SEASON SNOW AT DODGE
CITY: THERE HAVE ONLY BEEN THREE OCCURRENCES IN THE HISTORY OF
WEATHER RECORDS OF MEASURABLE SNOW IN THE MONTH OF MAY AT DODGE CITY:

1) 0.9 INCHES ON 3 MAY 1978
2) 0.7 INCHES ON 6 MAY 1915
3) 0.3 INCHES ON 4 MAY 1979

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1233 AM CDT SUN APR 28 2013

LIGHT BOUNDARY LAYER WINDS DUE TO A WEAK PRESSURE GRADIENT ACROSS
SOUTHWEST KANSAS WILL CONTINUE OVERNIGHT.  6 TO 8 DEGREE C DEW POINT
DEPRESSIONS FROM THE SURFACE TO THE MID LAYERS WILL HINDER ANY
STRATUS DEVELOP THROUGH THE OVERNIGHT AS WELL. THE RAPID REFRESH AND
LOCAL GFS MOS BOTH TREND WIND DIRECTION TOWARD THE SOUTHWEST AFTER
MIDNIGHT, WHICH IS ALSO UNFAVORABLE FOR FOG DEVELOPMENT.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.


&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  87  49  87  56 /   0   0  10  10
GCK  87  47  86  53 /   0   0   0  10
EHA  86  46  90  54 /   0   0   0   0
LBL  87  49  90  55 /   0   0   0   0
HYS  88  52  81  55 /   0  10  10  10
P28  85  54  88  58 /   0  10  10  10

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...RUSSELL








AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 506 AM EDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN APR 28 2013

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL FLOW FROM THE PACIFIC NW
TO THE NRN GREAT LAKES. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW
WAS MOVING THROUGH ERN SASK INTO MANITOBA WITH A TROUGH EXTENDING TO
THE CNTRL DAKOTAS. AHEAD OF THE TROUGH...SSW FLOW WAS INCREASING
OVER THE UPPER MS VALLEY AND NRN GREAT LAKES. WITH THE DRY AIRMASS
BELOW 700 MB...PER 00Z INL SOUNDING...WAA AHEAD OF THE TROUGH WAS
BRINGING MAINLY MID CLOUDS AND SOME VIRGA OR SPRINKLES INTO NRN MN.
ALTHOUGH DEWPOINTS HAD CLIMBED INTO THE MID 40S SRN AND CNTRL
MN...CIRCULATION AROUND THE LOW PRESSURE SYSTEM OVER SRN IL HAD
PREVENTED MORE ABUNDANT GULF MOISTURE FROM MOVING INTO THE REGION.

EXPECT THAT SUNSHINE AND MIXING TO 850-800 MB (850 MB TEMPS FROM 7C
TO 9C) WILL REULS IN MAX READINGS IN THE MID AND UPPER 60S EAST AND
LOWER 70S WEST. SRLY FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS
CLOSER TO 50.

AS THE SASKATCHEWAN LOW MOVES TO HUDSON BAY...IT WILL DRAG A COLD
FRONT INTO THE NRN GREAT LAKES TONIGHT. LOW LEVEL CONV NEAR THE
FRONT COMBINED WITH A WEAK SHORTWAVE MOVING OUT OF THE NRN PLAINS
WILL BE ENOUGH TO SUPPORT A BAND OF SHOWERS INTO UPPER MICHIGAN. THE
MODELS WERE IN GOOD AGREEMENT WITH THE FRONT AND PCPN BAND TRENDING
SLIGHTLY SLOWER. THE PCPN IS EXPECTED TO MOVE INTO THE WEST THIS
EVENING AND OVER THE CNTRL AND EAST OVERNIGHT. WITH ONLY WEAK
MID/UPPER LEVEL FORCING AND LIMITED MOISTURE INFLOW...OVERALL PCPN
AMOUNTS WILL BE LIGHT GENERALLY AOB 0.25 INCH...PER SREF PROB AND
CONSENSUS QPF. MDLS SUGGEST THAT ANY INSTABILITY TO SUPPORT TSRA WILL
REMAIN MAINLY TO THE S OF THE CWA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN APR 28 2013

BEST CONFIDENCE INTO WEDNESDAY...WITH MUCH REDUCED FORECAST
CONFIDENCE AFTER THAT. PUT PRIMARY EFFORTS/TIME INTO SHORTER TERM
GRIDS GIVEN FLOODING PROBLEMS THAT WILL BE MORE CONFINED TO SHORTER
TERM.

FOR MON...EXPECT A WEAK SFC TROUGH/COLD FRONT TO PUSH
THROUGH...KEEPING SFC TEMPS A LITTLE COOLER THAN YESTERDAY OR TODAY.
UP TO AROUND A QUARTER INCH OF QPF IS EXPECTED MON...BUT AT THE SAME
TIME MELTING OF THE SNOW PACK IS REDUCED BY EXTRA CLOUD COVER AND
COOLER TEMPS /ESPECIALLY NEAR LAKE SUPERIOR/...SO THESE TWO FACTORS
MAY CANCEL EACH OTHER OUT...STILL RESULTING IN A DECENT MELT
DAY...BUT THIS IS DIFFICULT TO DETERMINE.

TEMPORARY COOL DOWN MON COMES TO YET ANOTHER END WITH 60S AND 70
HIGH TEMPS OVER MUCH OF THE AREA TUE AS 850MB TEMPS INCREASE TO
AROUND 14C BY 18Z TUE. THESE WARMER TEMPS COME AHEAD OF ANOTHER
SYSTEM THAT WILL MOVE N OF LAKE SUPERIOR...WHICH BRINGS A COLD FRONT
ACROSS THE CWA LATE TUE INTO TUE NIGHT. MODELS ARE EVEN SHOWING
SOME CAPE ALONG AND AHEAD OF THE COLD FRONT...WHICH MAY RESULT IN
THUNDERSTORM ACTIVITY. THE HEAVIEST RAINFALL IS MAINLY FOCUSED OVER
THE ERN HALF OFF UPPER MI...AND WILL BE SOMETHING TO WATCH WITH
RESPECT TO CONTINUED FLOOD THREAT.

OTHER THAN THOSE SYSTEM...MODELS IN THE FARTHER EXTENDED SHOW LARGE
DISAGREEMENT IN THERMAL FIELDS...SO A WIDE VARIETY OF TEMPS ARE
POSSIBLE. ALTHOUGH MODELS DO SHOW GOOD GENERAL AGREEMENT...THE EXACT
PLACEMENT OF THE UPPER LOW THEY SHOW OVER THE CENTRAL CONUS BY FRI
IS ESSENTIAL FOR TEMPS/PRECIP. WILL JUST USE A CONSENSUS OF MODELS
FOR THIS PERIOD GIVEN THE UNCERTAINTY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 124 AM EDT SUN APR 28 2013

EXPECT VFR CONDITIONS TO PREVAIL THIS TAF PERIOD WITH RELATIVELY DRY
AIRMASS DOMINATING IN SW FLOW ARND HI PRES OVER NEW ENGLAND. NOT OUT
OF THE QUESTION THERE COULD BE SOME FOG...MAINLY AT SAW WHERE SFC
DEWPTS ARE HIER...BUT LEFT OUT OF THE FCST FOR NOW AS THE WIND MAY
REMAIN HI ENUF TO LIMIT DIURNAL TEMP DROP. AS THE PRES GRADIENT
TIGHTENS BTWN THIS HI AND FALLING MSLP IN THE PLAINS...EXPECT SOME
LLWS TO DVLP AT CMX/IWD OVERNGT. THE ONSET OF DAYTIME HEATING BY
MID/LATE SUN MRNG WL MIX OUT THE HIER WINDS AND ALLOW GUSTY SW WINDS
TO REACH THE SFC. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 00Z AHEAD OF
AN INCOMING COLD FNT...BUT LIMITED MSTR RETURN WL LIMIT PCPN
INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN VFR.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN APR 28 2013

WINDS SHOULD STAY BELOW 25KTS THROUGH THE PERIOD WITH NO GALES IN
SIGHT. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&

.HYDROLOGY...
ISSUED AT 503 AM EDT SUN APR 28 2013

SAW GOOD MELTING YESTERDAY AFTERNOON WITH HIGH TEMPS IN THE 60S AND
70S AFTER THE SNOW PACK WARMED UP FROM SUB-FREEZING TEMPS THE NIGHT
BEFORE. SINCE TEMPS ARE WELL ABOVE FREEZING TONIGHT...AND HIGH TEMPS
TODAY WILL BE SIMILAR TO YESTERDAY BUT WITH SLIGHTLY HIGHER DEW
POINTS...WE SHOULD SEE EVEN BETTER MELTING FOR A LONGER PERIOD OF
TIME THAN YESTERDAY. PLACES WITH SNOWPACK REMAINING WILL SEE RAPID
AND EXTENSIVE MELTING TODAY...CAUSING RUNOFF INTO TONIGHT INTO AREA
STREAMS. RIVERS OF PARTICULAR CONCERN AFTER THE MELTING TODAY WILL
BE THE TRAP ROCK RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON
COUNTIES...AND THE PESHEKEE RIVER. RUNOFF MAY NOT PEAK UNTIL
TONIGHT/MONDAY...AND EVEN GET FORTIFIED BY ADDITIONAL MELTING AND
EVEN SOME RAIN ON MONDAY. RAINFALL AMOUNTS WILL GENERALLY BE AROUND
A QUARTER OF AN INCH...OR POSSIBLY MORE IN A FEW AREAS AND WILL
START LATE THIS EVENING INTO MONDAY. ANY RAIN WILL ONLY ADD TO
HYDROLOGIC CONCERNS...AND WILL HAVE TO PAY CLOSE ATTENTION TO PRECIP
AMOUNTS MONDAY. FURTHER CHANCES OF PRECIPITATION ARE EXPECTED AS
COLD FRONT WORKS THROUGH ON TUESDAY...WHEN THERE MAY BE
THUNDERSTORMS TOO. OTHERWISE...ADDITIONAL CHANCES OF PRECIPITATION
ARE POSSIBLE THE REST OF THE WEEK AS FRONT STAYS CLOSE BY TO THE
AREA.

MELTING SCENARIOS REMAIN THE BIGGEST CONFIDENCE REDUCERS AT THIS
POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE MELT
FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS WILL
LIKELY END UP QUITE A BIT HIGHER. ONCE PLACE WHERE THE MELT
CORRECTION FACTOR WAS INCREASED FOR FOR THE MEN RIVER FORECAST GROUP
/RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH RESULTED IN
MUCH INCREASED FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND
MODERATE FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR
REPUBLIC/WITCH LAKE. WFO SURVEY OF THE PESHEKEE RIVER REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS COULD CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES LATE TODAY INTO MONDAY. OF
COURSE...MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS WE ARE ALSO
LOOKING AT THREAT OF AREAL FLOOD PROBLEMS WITH SMALLER
CREEKS/STREAMS AND STANDING WATER ON ROADS. FOR FURTHER
DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE LATEST RIVER
WATCHES /FFAMQT/.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...JLB
HYDROLOGY...TITUS







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 356 AM EDT SUN APR 28 2013

.SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

&&

.LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA BLOCK
OVER THE EASTERN HALF OF THE COUNTRY.

&&

.MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.AVIATION...ISSUED 1157 PM EDT SAT APR 27 2013

//DISCUSSION...

VFR CONDITIONS WILL GIVE WAY TO LOWER CIGS LATE TONIGHT INTO SUNDAY
AS LOW PRESSURE LIFTS INTO THE OHIO VALLEY. SCATTERED SHOWERS WILL
SPREAD NORTH INTO THE AREA WITH IFR/LIFR CIGS DEVELOPING. VLIFR WILL
EVEN BE POSSIBLE LATE IN THE FORECAST PERIOD AS THE LOW DRIFTS OVER
THE AREA AND PROVIDE BEST POOLING OF LOW LEVEL MOISTURE.

FOR DTW...VFR CONDITIONS WILL TRANSITION TO MVFR SUNDAY MORNING AND
THEN IFR AFTERNOON/EVENING AS SHOWERS SPREAD IN FROM THE SOUTH. THE
SHOWERS WILL PERSIST OFF/ON THROUGHOUT THE DAY...BUT WILL DIMINISH
AFTER 00Z AS CIGS POSSIBLY FALL TO LIFR WITH THE PASSAGE OF THE LOW.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BY 11Z-13Z.

* LOW CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...CB
LONG TERM....BT
MARINE.......CB
AVIATION.....DG


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).









AREA FORECAST DISCUSSION

NWS ST LOUIS MO

 315 AM CDT SUN APR 28 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 315 AM CDT SUN APR 28 2013

AREAS OF DRIZZLE AND ISO-SCT RAIN SHOWERS SHOULD FINALLY END TODAY
AS A SLOW-MOVING LOW PRESSURE SYSTEM CONTINUES MOVING AWAY FROM THE
AREA. RAP BUFKIT PROFILES SHOW MIXING TO AROUND H9 THEREFORE HIGHS
IN THE LOW/MID 60S TO AROUND 70 LOOK REASONABLE CONSIDERING INITIAL
CLOUD COVER AND MOIST LOW LEVELS FM RECENT RAINFALL. TEMPERATURES
WILL BE WARMER IN CENTRAL MO THAN IN SWRN IL BECAUSE OF QUICKER
CLEARING IN THE WESTERN CWA.

KANOFSKY

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 28 2013

(TONIGHT - WEDNESDAY)

UPPER LEVEL RIDGE WILL BUILD OVER ERN NOAM EARLY IN THE PERIOD AND
THEN PROCEED TO DOMINATE THRU THE MIDDLE OF THE WEEK...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE HI PLAINS BY WEDNESDAY.
THIS SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.

THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY AND TUESDAY
MAX TEMPS...BUT IN SEVERAL LOCALES...WENT A COUPLE DEGS HIGHER TO
SUPPORT H900-850 TEMPS ALOFT DEPICTED BY THE MODELS AND ANTICIPATED
SUNSHINE.  LOOK FOR UPR 70S-LO 80S ON MONDAY WITH MID 80S TUESDAY
WITH A MORE SW WIND EXPECTED.  AN OUTSIDE CHANCE AT UPR 80S WILL
PRESENT ITSELF FOR PARTS OF STL METRO TUESDAY.  LOSS OF W COMPONENT
TO SFC WND ON WEDNESDAY AND SOME UNCERTAINTY ON WHERE FRONT WILL
BE...HAVE 80-85F FCSTD FOR MOST SPOTS.

TWO SMALL WINDOWS OF OPPORTUNITY FOR RAIN THIS PERIOD.  THE FIRST IS
ON MONDAY AFTERNOON-NIGHT.  MODELS ALL SHOW PRETTY STOUT INSTABILITY
AND 0-6KM BULK SHEAR OF 30-35KTS IN PLACE AHEAD OF WHAT SHOULD BE A
CDFNT EDGING INTO THE NWRN FA BY LATE MONDAY AFTERNOON BEFORE IT
STALLS AND WASHES OUT MONDAY NIGHT.  HOWEVER...SOME OF THESE LARGE
INSTABILITY VALUES ARE PREDICATED ON WHAT LOOKS TO BE A TOO
AGGRESSIVE LO LEVEL MOISTURE RETURN...AND A DEPENDENCE IN PART ON
SFC DWPTS REACHING INTO THE MID-UPR 60S.  HOWEVER...LO LEVEL MASS
FIELDS DO NOT SUPPORT A LO LEVEL MOISTURE RETURN OF THAT MAGNITUDE
WITH WEAK FLOW AND A WEAK BLOCKING RIDGE NEAR THE GULF OF MEXICO
UNTIL MONDAY AFTERNOON AND THEN IT SHOULD BE TOO SMALL A TIME PERIOD
TO GET THE RICH MOISTURE THAT FAR N.  SFC DWPTS INSTEAD EDGING NEAR
60F LOOK MORE LIKELY BUT THIS WILL STILL YIELD CINH VALUES AT OR
ABOVE 20 J/KG WHICH WILL PROBABLY BE ALL IT WILL NEED TO BLOCK MOST
CONVECTION WITH A WEAKENING SFC FRONT.  BUFR SOUNDINGS BASED ON OUR
LOCAL WRF DEPICT THIS WELL.  SO...IF SOMETHING CAN POP...IT SHOULD
SUPPORT DAY SHIFT YESTERDAY/S ASSERTION WITH DECENT CHANCE OF IT
GOING TO SEVERE...BUT OCCURRENCE OF ANY CONVECTION LOOKS TO BE
PRETTY LIMITED.  AFTER SUNSET MONDAY EVENING...CINH RAPIDLY
INCREASES WITH THE SFC FRONT STARTING TO WASH OUT...AND SO WINDOW
FOR CONVECTION WILL RAPIDLY CLOSE.  MADE MINIMAL CHANGES TO PREVIOUS
FCST WHICH ALREADY HAD MINIMAL CHC POPS LIMITED TO THE NW FA.

STILL SOME MODEL DIFFS ON TIMING OF THE SFC CDFNT FOR MID-LATE
WEEK...WITH THE GFS CONTINUING TO BE THE FASTEST INTO OUR AREA BY
WEDNESDAY AFTERNOON WITH THE ECMWF SOME 12HRS LATER INTO EARLY
THURSDAY MORNING.  BACKED OFF SOME ON POPS FOR WEDNESDAY WITH THE
ECMWF CONTINUING TO LEAD THE GFS TO WHAT HOPEFULLY WILL BE THE
VERIFYING SOLN...WHICH HAS STEADILY BEEN FAVORING A SLOWER FROPA.

(THURSDAY - SATURDAY)

LOOKING INCREASINGLY LIKE A COOL AND WET PERIOD.

THE LARGE DISCREPANCY ON WHEN AND WHERE TO FORM THE CUTOFF LO HAS
BEEN OVERCOME FOR THE MOST PART WITH THE GFS FOLLOWING THE ECMWF/S
LEAD FOR A MORE RAPID FORMATION...AND FURTHER W AS A RESULT.  STILL
SOME SMALL DIFFS AND EXPECT TO SEE SOME WOBBLING THE NEXT DAY OR
TWO.  UNFORTUNATELY...WHEN DEALING WITH CUTOFF UPPER LOWS...EVERY
WOBBLE WILL MAKE A PRETTY BIG DIFFERENCE ON RAIN CHCS AND TEMPS.

THE LATEST ITERATION FROM THE 00Z MODELS HAS A GENERAL CONSENSUS ON
THE UPPER LO FORMING AROUND THE INTERSECTION OF KS-MO-OK-AR ON
FRIDAY AND THEN GRADUALLY PULLING NWD THRU SATURDAY.  THOSE SLIGHT
DIFFS WILL MAKE A BIG DEAL AT THE SFC...WHERE ECMWF SHOWS A MORE
AGGRESSIVE CDFNT PUSH ON THURSDAY WITH NOTHING OF THE SORT FROM THE
GFS AND SO A LARGE TEMP FCST DIFF AS A RESULT ARISES...ESPECIALLY
THURSDAY NIGHT AND FRIDAY.  A BROAD CONSENSUS APPROACH PREFERRED FOR
TEMPS AS A RESULT.

ONE THING THAT LOOKS INCREASINGLY LIKELY IS THE RAIN CHCS...
ESPECIALLY IF THE UPPER LO SETS UP IN THE RIGHT SPOT ALMOST LIKE
MODELS DEPICT NOW...COULD BE SOME HEAVY RAINFALL POTENTIAL AS IT
TAPS INTO GULF OF MEXICO MOISTURE.

TES

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1037 PM CDT SAT APR 27 2013

RAIN CONTINUES TO ROTATE THROUGH THE AREA BETWEEN UIN AND STL
UNDERNEATH AND AHEAD OF A MID LEVEL LOW JUST NW OF STL...AND
ALONG AND AHEAD OF THE INVERTED SFC TROUGH EXTENDING FROM A SFC
LOW OVER NWRN TN NW THROUGH ERN MO. MOST OF THIS RAIN SHOULD SHIFT
E OF THE TAF SITES BY 06Z SUN. ALTHOUGH MOST OF THE RAIN SHOULD
END LATE TGT THE CLOUD CEILING SHOULD REMAIN QUITE LOW...MAINLY
BELOW 1000 FT. SHOULD ALSO HAVE LIGHT FOG WITH PATCHY DRIZZLE DUE
TO PLENTY OF SFC/BOUNDARY LAYER MOISTURE. WEAK NLY SFC WIND WILL
BACK AROUND TO A NWLY DIRECTION LATE TGT AS THE SFC LOW MOVES E OF
THE TAF SITES. THE SFC WIND WILL CONTINUE TO BACK AROUND TO A
W-SWLY DIRECTION SUN AFTN AS WEAK SFC RIDGING BEHIND THE SFC LOW
BEGINS TO SHIFT E OF THE TAF SITES. THE FOG WILL DISSIPATE BY LATE
SUN MRNG WITH A GRADUAL RISE IN CLOUD CEILING HEIGHT INTO THE VFR
CATAGORY SUN AFTN AS WELL AS EVENTUAL SCATTERING OUT OF THE
CEILING. THE SFC WIND WILL BE MAINLY SLY SUN EVNG...ALBEIT QUITE
LIGHT WITH A CLEAR SKY.

SPECIFICS FOR KSTL...MOST OF THE RAIN SHOULD BE E OF STL LATE
TGT...ALTHOUGH THERE MAY STILL BE SOME PATCHY DRIZZLE. LIGHT FOG
CAN BE EXPECTED AS WELL WITH THE CEILING HEIGHT REMAINING BELOW
1000 FT. THE CLOUD CEILING WILL LIKELY RISE INTO THE MVFR CATAGORY
BY LATE SUN MRNG WITH THE FOG DISSIPATING. THE CEILING WILL
CONTINUE TO RISE INTO THE VFR CATAGORY BY LATE SUN AFTN...THEN
CLEAR OUT EARLY SUN EVNG. NLY SFC WIND WILL BACK AROUND TO A NWLY
DIRECTION LATE TGT...THEN TO A WLY DIRECTION SUN AFTN...AND TO A
LIGHT S-SWLY WIND SUN EVNG.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 337 AM CDT SUN APR 28 2013
...CORRECTION FOR TYPO...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN APR 28 2013

SFC WINDS SHOULD INCREASE FROM THE WEST TOWARD MORNING AHEAD OF A
PACIFIC COLD FRONT FCST TO MOVE THROUGH DURING THE AFTN. THE RAP
SUPPORTS HIGHS IN THE MID 80S AHEAD OF THE FRONT ACROSS SWRN NEB AND
WINDS SHOULD INCREASE TO 15 TO 25 MPH AHEAD AND BEHIND THE FRONT.

FOR TONIGHT...A DISTURBANCE...CURRENTLY ACROSS THE NRN ROCKIES WILL
MOVE THROUGH NRN NEB. K INDICES SUPPORT TSTMS WEST OF HIGHWAY 83.
MOISTURE BELOW 700MB IS VERY LIMITED EAST OF 83 AND LAPSE RATES
NEARLY MOIST ADIABATIC.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN APR 28 2013

GUSTY SOUTHERLY WINDS AND CRITICALLY LOW RELATIVE HUMIDITY VALUES TO
BE EXPECTED ONCE AGAIN MONDAY AFTERNOON...WITH THE POTENTIAL OF
WIDESPREAD RED FLAG CONDITIONS.  FIRE HEADLINES MAY BE NECESSARY
ONCE AGAIN.  A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE
HIGH PLAINS ON MONDAY...ALLOWING FOR DOWNSLOPING SOUTHWESTERLY TO
WESTERLY WINDS AND HIGHS WELL INTO THE UPPER 70S...IF NOT LOW 80S.
WIND GUSTS WILL LIKELY EXCEED 25 MPH DURING PEAK HEATING AS THE
PRESSURE GRADIENT INCREASES AND STRONG TROPOSPHERIC MIXING
COMMENCES.  PREVIOUS FORECAST HAD HIGHS HANDLED WELL FOR
MONDAY...WITH ONLY MINOR UPWARD TWEAKS NEEDED ACROSS NORTHWESTERN
NEBRASKA...WHERE TEMPERATURES MAY SOAR IN ADVANCE OF A COLD FRONTAL
PASSAGE.  THE FRONT IS CURRENTLY PROGGED TO ARRIVE OVERNIGHT
MONDAY/EARLY TUESDAY...HOWEVER THERE IS LITTLE SUPPORT FOR
PRECIPITATION PRODUCTION INITIALLY.  PROXIMITY SOUNDINGS REVEAL VERY
LITTLE MOISTURE IN THE LOWER LEVELS...THUS WILL CONTINUE THE SILENT
14 POPS THROUGH THE OVERNIGHT.  TEMPERATURES HOWEVER WILL BE
NOTICEABLY COOLER ON TUESDAY...BUT THERE REMAINS DIFFERENCES BETWEEN
THE DETERMINISTIC SOLUTIONS IN THE AMOUNT OF COOLING...THE CONSENSUS
WOULD SUGGEST A 20-25F DECREASE IN HIGHS FROM MONDAY...WILL GO WITH
A RANGE OF HIGHS FROM THE MID 50S TO LOW 60S ACROSS THE CWA.  ALONG
WITH THE COOLER TEMPERATURES...PRECIPITATION CHANCES INCREASE
TUESDAY INTO WEDNESDAY AS A MIDLEVEL SHORTWAVE AND ASSOCIATED RRE OF
A 110 PLUS KT UPPER JET ADVANCES ON THE REGION.  THE HIGHEST QPF
WILL BE TIED TO THE MID-LEVEL FRONTOGENETIC FORCING WHICH SHOULD
BISECT THE CWA FROM SOUTHWEST TO NORTHEAST...WHICH MEANS CHANCES ARE
INCREASING FOR WELCOME WIDESPREAD QPF ACROSS THE HEART OF THE
SANDHILLS.  PTYPE MAY BECOME PROBLEMATIC EARLY ON WEDNESDAY...AS H85
TEMPERATURES ARE SHOWN TO FALL AS COLD AS -3C BY 12Z WEDNESDAY.
WILL INTRODUCE A RAIN/SNOW MIX ACROSS NORTHWEST NEBRASKA FROM
06Z-12Z...BUT NOT EXPECTING ANY ACCUMULATIONS AS GROUND TEMPERATURES
HAVE WARMED GREATLY.  GUIDANCE CAME IN COOLER ONCE AGAIN FOR
WEDNESDAY...AND GIVEN EXPECTED CLOUDY CONDITIONS WITH WEAK OR
NEUTRAL CAA...HIGHS IN THE LOWER 40S SHOULD BE THE NORM.  THE
REMAINDER OF THE EXTENDED FORECAST REMAINS INTERESTING AS A CLOSED
LOW DEVELOPS OVER CENTRAL KANSAS ON THURSDAY...AND THEREAFTER
MEANDERS AIMLESSLY THROUGH THE MISSOURI VALLEY/CORN BELT THROUGH THE
WEEKEND.  WITH BROAD CYCLONIC FLOW REMAINING ACROSS THE CENTRAL
CONUS...WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES INTO NEXT
WEEKEND WITH CONTINUED SLIGHT CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1243 AM CDT SUN APR 28 2013

THROUGH SUNDAY AFTERNOON...SCATTERED HIGH CLOUDINESS WILL MOVE IN
FROM THE WEST IN ADVANCE OF AN APPROACHING UPPER LEVEL
DISTURBANCE. CLOUDS WILL THICKEN SUNDAY EVENING AS THE DISTURBANCE
BEGINS TO TRACK ACROSS NORTHERN NEBRASKA. ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS ARE POSSIBLE SUNDAY EVENING ACROSS
NORTHERN NEBRASKA...AND MAY IMPACT THE KVTN TERMINAL AFTER 02Z
MONDAY WITH CIGS DOWN TO 5000 FT AND VSBYS DOWN TO 4SM. WINDS OVER
THE NEXT 24 HOURS...WILL GRADUALLY SHIFT FROM THE WEST TO THE
NORTH...THEN NORTHEAST. WIND SPEEDS WILL RANGE FROM 10 TO 15 KTS.


&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT SUN APR 28 2013

RED FLAG CONDITIONS SHOULD DEVELOP AHEAD AND BEHIND THE COLD FRONT
FORECAST TO MOVE THROUGH SWRN NEB THIS AFTN. THE RAP AND HRRR ARE
LEADING THE WAY WITH DEW PTS IN THE 20S WHILE THE MOSGUIDE WIND
GUSTS ARE IN THE 20 TO 24 KT RANGE. THE DRIER MODEL DATA AND
STRONGER WIND GUSTS HAVE BEEN VERIFYING BETTER THAN THE WETTER
MODELS WHICH HAVE BEEN AS MUCH AS 10F TOO HIGH WITH DEW POINTS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 8 PM CDT /7
PM MDT/ THIS EVENING FOR NEZ204-206-209-210-219.

&&

$$

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC












AREA FORECAST DISCUSSION

NWS HASTINGS NE

 100 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 1257 AM CDT SUN APR 28 2013

INCLUDED SOME FOG AND STRATUS IN THE SOUTHEASTERN CWA AS THE HRRR
ADVERTISES. THE HRR WAS SPOT ON WITH THE FOG LAST NIGHT...SO
CONTINUING WITH MORE CONFIDENCE IN THE HRRR OVER ANYTHING ELSE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 327 PM CDT SAT APR 27 2013

PLEASANT CONDITIONS IN PLACE ACROSS THE CWA THIS AFTERNOON...SITTING
ON THE BACKSIDE OF AN UPPER LEVEL LOW PRESSURE SYSTEM GRADUALLY
MAKING ITS WAY EAST ACROSS MISSOURI.  AT THE SURFACE...THE CWA IS IN
BETWEEN A TROUGH OF LOW PRESSURE DRAPED THROUGH THE HIGH PLAINS AND
HIGH PRESSURE FROM TX INTO IA...BRINGING SWRLY WINDS...BUT WITH A
WEAK PRESSURE GRADIENT SPEEDS ARE ON THE LIGHTER SIDE.  STARTED OFF
THE DAY WITH A LOT OF FOG AND STRATUS...BUT BY MIDDAY MOST OF THAT
HAD BURNED OFF...LEAVING MOSTLY CLEAR SKIES BEHIND.

THROUGH THE REST OF THE SHORT TERM PERIOD...THE FORECAST REMAINS
DRY...WITH MODELS CONTINUING TO SHOW WEAK SHORTWAVE RIDGING SHIFTING
INTO THE AREA TONIGHT AND SLIDING EAST TOMORROW BETWEEN THE
DEPARTING LOW CURRENTLY OVER MISSOURI AND ANOTHER DISTURBANCE
STARTING TO SWING INTO THE DAKOTAS.  SHOULD START TO SEE A FEW MORE
CLOUDS WORK IN FROM NORTH DURING THE AFTERNOON...OTHERWISE EXPECTING
MOSTLY CLEAR SKIES.  LOOKING AT THE SFC PATTERN...WINDS WILL
CONTINUE OUT OF THE SOUTHWEST...THEN MORE WESTERLY AS A SFC FRONT
ACCOMPANYING THAT UPPER LEVEL DISTURBANCE INCHES CLOSER TO THE CWA.
THERE CONTINUES TO BE SOME MODEL HINT AT SOME LIGHT PRECIP TRYING TO
CREEP INTO NRN PORTIONS OF THE CWA LATE TOMORROW AFTERNOON...BUT
WITHOUT MORE SUPPORT FROM OTHER MODELS...AND FORECAST SOUNDING BEING
PRETTY DRY IN THE LOWER LEVELS...KEPT THINGS DRY.

WILL SEE ANOTHER PUSH OF WARMER AIR ALOFT...AND ALONG WITH GOOD
MIXING POTENTIAL AND SW/WRLY WINDS...EXPECTING ANOTHER BUMP UP IN
TEMPERATURES....WITH HIGHS FORECAST IN THE LOWER 80S.  THE COMBO OF
FORECAST TEMPS AND DEWPOINTS WILL RESULT IN RH VALUES DOWN IN THE
MID TEENS TO MID 20S...BUT WIND SPEEDS REMAINING IN THE 10 TO 15 MPH
RANGE WILL HELP KEEP FIRE WX CONCERNS IN CHECK.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 PM CDT SAT APR 27 2013

AFTER A WARM START...TEMPERATURES WILL TURN COLDER DURING THE
EXTENDED WITH INTERMITTENT CHCS FOR PCPN UNDER INFLUENCE OF AN
UPPER LOW PRESSURE SYSTEM IN A BLOCKY PATTERN.

SUNDAY NIGHT...A 75KT JET STREAK WILL CROSS THE NORTHERN PLAINS
REGION WITH A LEAD SHORTWAVE TROUGH AND SFC TROUGH/SUBTLE COOL FRONT
ADVANCING SOUTH SUNDAY NIGHT WHILE ANOTHER WAVE TRANSLATES EAST
ACROSS NORTHERN NEB OVERNIGHT.  OUR NORTHERN ZONES COULD SEE SOME
LIGHT PCPN WITH THIS SYSTEM BUT INSTABILITY IS HIT OR MISS HAVE
KEPT THINGS AS SHOWERS ATTM.

SFC RIDGE AXIS WHICH SETTLES IN BEHIND THE BOUNDARY SHIFTS EAST
MONDAY WITH RETURN FLOW SETTING UP AND FRONT LIFTS BACK
NORTH...RESULTING IN ANOTHER DAY OF WARM SPRING TEMPS WELL INTO THE 70S
TO LOWER 80S. A STRONGER WAVE/TROUGH TRANSLATES SOUTHEAST FM
CANADA ACROSS THE NORTHERN PLAINS/DAKOTAS MONDAY NIGHT...SENDING A
STRONGER COLD FRONT SOUTH INTO THE CENTRAL PLAINS. THE NAM REMAINS
THE FASTEST WITH FROPA THAN OTHER MODELS AND HAVE TRENDED TOWARD
ENSEMBLES FOR TIMING WHICH IS FAIRLY CLOSE TO GFS AS WELL. THE
FRONTAL BOUNDARY REACHES OUR SE NEB COUNTIES INTO NC KS MID DAY
TUESDAY. MOISTURE POOLS ALONG THE FRONT AND INSTABILITY
INCREASES...AND GOOD SHEAR IS PRESENT AS WELL ALONG THE
BOUNDARY...ESPECIALLY OVERNIGHT AS THE LLVL JET STRENGTHENS. CHCS FOR
CONVECTION INCREASE BY EVENING AND CONTINUE THRU THE OVERNIGHT
HOURS AND STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL/WIND THE
PRIMARY HAZARDS IN VCNTY OF BOUNDARY.

MUCH COLDER AIR PUSHES SOUTH BEHIND THE FRONT WEDNESDAY AND IN
DYNAMICS WITH MID LEVEL FRONTOGENESIS AND WAVE MOVING ONTO THE
PLAINS...PCPN CHCS CARRY INTO BOTH WEDNESDAY/WEDNESDAY NIGHT. H85
TEMPS DROP BELOW FREEZING WEDNESDAY AND AS COLD AIR CONTINUES TO
DEEPEN...A R/S MIX LOOKS PROBABLE WEDNESDAY NIGHT AS LLVL TEMPS
COOL. IT LOOKS LIKE THE BRUNT OF THE COOLER AIR ARRIVES ON THE
TAIL END OF THE PCPN...BUT SOMETHING TO WATCH AND FOLLOWED CLOSER
TO MODEL THICKNESS VALUES FOR THE R/S LINE.

THE UPPER TROUGH DEEPENS ACROSS THE INTERIOR CONUS BY THURSDAY IN
A BLOCKING PATTERN WITH AN UPPER RIDGE ALONG THE EAST COAST AND
RIDGING ALONG THE WEST COAST. THE UPPER LOW IS PROGGED TO CLOSE
ACROSS THE CENTRAL PLAINS AND MEANDER ACROSS OUR REGION THROUGH
NEXT WEEKEND. THIS WILL RESULT IN A COLD AND PERIODIC WET PERIOD
THURSDAY THRU SATURDAY. DEPENDING ON TEMP PROFILE R/S IS POSSIBLE
BUT HAVE KEPT THINGS AS MAINLY RAIN ATTM UNTIL THERMAL PROFILE CAN
BE MORE CLOSELY EVALUATED AS SYSTEM AND EXTENDED PERIODS DRAW CLOSER.
WILL ALSO NEED TO MONITOR LOW TEMPS FOR POTENTIAL FOR READINGS
NEAR THE FREEZING MARK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 125 AM CDT SUN APR 28 2013

ONLY MID-HIGH LEVEL SKY COVER FOR THIS FORECAST. AS THE PRESSURE
GRADIENT INCREASES BY SUNDAY AFTERNOON...A BIT OF A GUST IS
POSSIBLE OUT OF THE WEST AS A DRY LINE MOVES EAST INTO THE
AREA AND A COLD FRONT APPROACHES FROM THE NORTH. SOME
THUNDERSTORMS ARE POSSIBLE TO THE NORTHEAST...BUT SHOULD REMAIN
OUT OF THE AREA.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

UPDATE...HEINLEIN
SHORT TERM...ADO
LONG TERM...FAY
AVIATION...HEINLEIN







AREA FORECAST DISCUSSION

NWS RALEIGH NC

 303 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SLOW MOVING STORM SYSTEM OVER THE MISSISSIPPI VALLEY WILL APPROACH
THE AREA LATE TODAY AND TONIGHT... THEN CROSS THE REGION ON MONDAY.
RAIN IS EXPECTED TO OVERSPREAD THE REGION FROM THE WEST TODAY... AND
CONTINUE TONIGHT INTO MONDAY.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 845 PM SATURDAY:

REST OF TONIGHT: THE DE FACTO THEME OF RECENT FORECASTS HAS BEEN TO
SLOW DOWN THE ARRIVAL OF RAIN... AS THIS INCOMING STORM SYSTEM HAS
BEEN PROGRESSING VERY SLOWLY EASTWARD... AND THE MODELS HAVE
CONTINUED TO STEADILY DELAYED PRECIP ARRIVAL FOR SEVERAL RUNS NOW.
THIS THEME MUST BE CONTINUED THIS EVENING... AS THE NEWEST
FINE-SCALE CONVECTION-ALLOWING MODEL RUNS GREATLY HOLD BACK THE
ARRIVAL OF SIGNIFICANT RAIN IN THE WESTERN CWA UNTIL CLOSE TO
DAYBREAK. ONE BROKEN BAND OF WEAKLY FORCED RAIN HAS STREAKED ACROSS
SWRN NC AND THE NC/SC BORDER IN THE LAST SEVERAL HOURS... SUPPORTED
IN PART BY SHEARING MID LEVEL VORTICITY. UPPER DIVERGENCE WILL
WEAKEN OVER NC AS A JET STREAK HEADS OFFSHORE WITH MID LEVEL RIDGING
BUILDING IN TONIGHT AHEAD OF THE INCOMING SLOW-MOVING SHORTWAVE
TROUGH OVER THE MID MISS VALLEY... LEADING TO DISSIPATION OF FORCED
ASCENT OVER NC. THE LOW LEVELS OVER THE WESTERN CWA HAVE MOISTENED
UP QUICKLY EARLY THIS EVENING BUT NOT SO IN THE NORTHEAST CWA... AND
THE RAP AND LOCAL WRF BRING THE SLIGHTLY DRIER AIR NOW OVER NE NC/SE
VA WESTWARD TONIGHT (DUE TO THE ESE SURFACE CIRCULATION AROUND THE
SURFACE HIGH CENTERED OFF DELMARVA)... A REASONABLE TRAJECTORY. WITH
THE WANING FORCING OVER NC... AND WITH THE STRONG SOUTHWESTERLY 850
MB JET THAT IS HELPING TO DRIVE THE CONVECTION OVER AL/N GA/E TN
EXPECTED TO HOLD WELL TO OUR WEST OVERNIGHT (ACCELERATING UP INTO
FAR WRN WV)... WE`RE UNLIKELY TO SEE ENOUGH OF A SURGE IN MOISTURE
OR INCREASE IN LIFT FOR ANYTHING BUT PATCHY VERY LIGHT RAIN OR
SPRINKLES UNTIL CLOSE TO SUNRISE. WILL LEAVE IN PATCHY SPRINKLES IN
THE WEST AND SOUTH FOR MUCH OF THE NIGHT... BUT WILL HOLD OFF THE
HIGHER POPS IN THE WESTERN CWA UNTIL AFTER 5 AM. THE OVERCAST MID
AND HIGH CLOUDS WILL HELP KEEP TEMPS UP OVERNIGHT... BUT ONLY SMALL
ADJUSTMENTS ARE NEEDED... LOWS NEAR 50 NORTHEAST TO MID 50S
SOUTHWEST. -GIH

THROUGH SUNDAY:
RAIN CHANCES WILL SLOWLY BUT STEADILY INCREASE FROM WEST TO EAST
THROUGH THE DAY ON SUNDAY AS THE BLOCKING RIDGE OVER THE EASTERN
SEABOARD SHIFTS OFFSHORE...ALLOWING THE UPPER TROUGH TO FINALLY
PROGRESS EASTWARD INTO THE APPALACHIANS. PWATS INCREASE TO 1.2-1.3"
LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT((2 STANDARD DEVIATIONS
ABOVE NORMAL)WITH THE EASTWARD PUSH OF SOUTHERLY 30KT LOW-LEVEL FEED
OF GULF MOISTURE INTO THE AREA. THUS...EXPECT CHANCES FOR RAIN TO
PRIMARILY BE CONFINED WEST OF HWY 1 THROUGH THE EARLY-MID AFTERNOON
BEFORE EVENTUALLY SPREADING EAST OF HWY 1 SUNDAY EVENING/NIGHT.

WIDESPREAD CLOUD COVER AND AREAL COVERAGE OF PRECIP WILL BE THE MAIN
DETERMINING FACTOR ON TEMPERATURES THROUGH THE PERIOD. OVERNIGHT LOWS
IN THE 50S EACH NIGHT. HIGHS SUNDAY...WILL BE VERY CAD
LIKE...ESPECIALLY IF RAINFALL THROUGH THE AFTERNOON IS CONFINED TO
WESTERN PORTIONS OF THE STATE. HIGHS IN THE LOWER 60S WEST TO LOWER
70S EAST.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 255 PM SATURDAY...

WIDESPREAD PRECIP WILL BE ONGOING TO START MONDAY MORNING. THIS
PRECIP WILL BE MAINLY CAUSED BY AN EASTWARD PROGRESSING UPPER
WAVE...ALTHOUGH SOME MODELS ARE ALSO HINTING AT A WEAK SURFACE WAVE
DEVELOPING...WHICH WOULD ALSO ENHANCE THE PRECIP. THE UPPER TROUGH
IS PROGGED TO BE ALMOST DIRECTLY OVERHEAD MONDAY AFTERNOON AND THEN
BE MOVING OFFSHORE BY MONDAY NIGHT. ANY RESIDUAL COOL STABLE CAD
LAYER SHOULD SCOUR OUT THROUGHOUT THE DAY ON MONDAY AS THE SURFACE
HIGH PROGRESSES FURTHER OFFSHORE AND SOUTHERLY FLOW TAKES OVER. AS A
RESULT...HAVE INCREASED TEMPS TO THE MID/UPPER 60S TO THE LOWER 70S.
IN ADDITION...WITH THE WARMER TEMPS AND THE FACT THAT THE UPPER
LEVEL TROUGH SHOULD BE RIGHT OVERHEAD DURING THE HEATING OF THE
DAY...THERE COULD BE SOME SCATTERED THUNDERSTORMS THAT DEVELOP
MONDAY AFTERNOON. AS THE UPPER LEVEL TROUGH AXIS SHIFTS EAST OF THE
REGION MONDAY NIGHT...DRIER AIR ALOFT WILL FILTER IN AND THE PRECIP
COVERAGE SHOULD DECREASE FROM WEST TO EAST MONDAY EVENING/NIGHT.
STORM TOTAL PRECIP (INCLUDING AMOUNTS THAT FALL BEFORE MONDAY) ARE
EXPECTED TO BE BETWEEN 1-2 INCHES. OVERNIGHT LOWS SHOULD GENERALLY
BE IN THE MID 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 303 AM SUNDAY...

FINALLY... SOME AGREEMENT WITH THE OPERATIONAL MODELS WITH THE
DEVELOPING BLOCKY MID/UPPER LEVEL FLOW PATTERN EXPECTED TO EVOLVE
THIS WEEK. THE TRANSITION SEASON IS CLIMATOLOGICALLY FAVORABLE FOR
"CUT OFF LOWS" WITH APRIL AND MAY THE PRIME MONTHS. THE FAVORED
LOCATION IS IN THE CENTRAL AND EASTERN UNITED STATES. THIS WEEK WILL
NOT DISAPPOINT WITH REGARDS TO A LARGE "CUT OFF LOW" THAT WILL BE
SLOW TO MOVE ACROSS THE PLAINS. MORE IMPORTANTLY TO OUR WEATHER WILL
BE THE LARGE DEVELOPING RIDGE DOWN THE EASTERN SEABOARD THAT WILL
BLOCK THIS STORM TO OUR WEST FOR THE BULK OF THE WEEK.

A COUPLE OF LARGE UPPER RIDGES ARE FORECAST TO DEVELOP MID TO LATE
WEEK OVER SOUTHEASTERN AND SOUTHWESTERN CANADA. THIS WILL HELP THE
TROUGH DEVELOPING OVER THE CENTRAL PLAINS TO "CUT OFF" LATE THIS
WEEK. DUE TO THE BLOCKING EXPECTED OVER SE CANADA AND THE
STRENGTHENING SURFACE HIGH PRESSURE THAT IS FORECAST TO EXTEND FROM
NEW ENGLAND DOWN THE EASTERN SEABOARD MID TO LATE WEEK... THE "CUT
OFF LOW" OVER THE PLAINS WILL VERY SLOWLY MOVE EAST TOWARD THE OHIO
VALLEY BY NEXT WEEKEND. THE WEATHER ASSOCIATED WITH THIS UPPER LOW
AND THE TRAILING SURFACE COLD FRONT WILL REMAIN WEST OF THE
APPALACHIANS THIS WEEK... WITH THE POTENTIAL FOR THE FRONT TO FALL
APART BEFORE REACHING EAST OF THE MOUNTAINS NEXT WEEKEND.

AS MENTIONED IN THE PREVIOUS DISCUSSION FROM SATURDAY AFTERNOON...
ADJUSTMENTS TOWARD A DRIER FORECAST WILL HAVE TO BE MADE MID TO LATE
WEEK FOR OUR REGION. WE WILL CONTINUE TO TREND THAT WAY WITH ADDED
CONFIDENCE WITH THIS FORECAST. ALSO... TEMPS MID TO LATE WEEK WILL
BE COOLER THAN NORMAL GIVEN THE EXPECTED PROLONGED NORTHEAST FLOW
ASSOCIATED WITH THE LARGE SURFACE HIGH PRESSURE CENTERED TO OUR
NORTH AND NORTHEAST.

SENSIBLE WEATHER... THE DEVELOPING AND DEEPENING NE FLOW ON TUESDAY
SHOULD LEAD TO AMPLE LOW LEVEL MOISTURE TRAPPED UNDER AN INVERSION
ALOFT. VARIABLY TO MOSTLY CLOUDY SKIES SHOULD BECOME OVERCAST LATE
TUESDAY INTO WEDNESDAY. THIS WILL TEMPER DAYTIME TEMPERATURES.
FORECAST SOUNDINGS INDICATE THAT IT MAY BE THURSDAY BEFORE SOME
DRIER AIR WORKS ITS WAY INTO THE AREA FROM THE NORTH. WE WILL KEEP A
SMALL CHANCE OF SHOWERS BOTH TUESDAY AND WEDNESDAY AS MODELS SUGGEST
A SLIGHT UPTICK IN THE CHANCE OF SHOWERS DURING THE AFTERNOON AND
EARLY EVENING HOURS BOTH DAYS. INSTABILITY SHOULD BE LACKING AND
THUNDER IS NOT CURRENTLY EXPECTED. THIS SHOULD BE FOLLOWED BY A DRY
FORECAST FOR THU-FRI. SATURDAY... STILL UP FOR DEBATE BUT THE SLOWER
FORECAST DUE TO BLOCKING IS FAVORED.

TUESDAY AND WEDNESDAY... LOW OVERCAST AT NIGHT WITH MOSTLY CLOUDY
AFTERNOON`S. A CHANCE OF MAINLY AFTERNOON SHOWERS. LOWS IN THE MID
50S TO AROUND 60. HIGHS 68-75 TUESDAY... AND 65-72 WEDNESDAY. PARTLY
SUNNY AND EVEN COOLER THURSDAY AND FRIDAY. LOWS 45-50. HIGHS 65-70.
PARTLY SUNNY SATURDAY. LOWS AROUND 50. HIGHS 70-75.


&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 110 AM SUNDAY...

VFR CONDITIONS WITH CEILINGS BETWEEN 5000-10000FT WILL OCCUR
OVERNIGHT THROUGH THE EARLY MORNING HOURS. AN INCREASING LOW LEVEL
SE FLOW WILL ADVECT ADDITIONAL MOISTURE INTO CENTRAL NC WHILE AN
AREA OF LOW PRESSURE LIFTS N-NE ACROSS THE OH VALLEY. THIS WEATHER
SYSTEM WILL BRING AREAS OF RAIN TO THE WESTERN PIEDMONT INCLUDING
KINT AND KGSO BY LATE MORNING. THIS WILL LEAD TO MVFR/IFR CEILINGS
TO THE TRIAD REGION TERMINALS BY MID DAY. THE LEADING EDGE OF THE
RAIN SHIELD WILL CREEP EWD THIS AFTERNOON AND TONIGHT...EVENTUALLY
REACHING KRDU...KRWI AND KFAY LATE THIS AFTERNOON-EARLY EVENING. THE
RAIN WILL CONTINUE TONIGHT INTO MOST OF MONDAY THEN DIMINISH FROM
THE WEST LATE MONDAY AND MONDAY NIGHT.

WHILE THE RAIN WILL END...THE MVFR-IFR CEILINGS WILL PERSIST MONDAY
NIGHT INTO TUESDAY AS MOISTURE WILL REMAIN TRAPPED BELOW A MID LEVEL
INVERSION. A NE FLOW IN THE LOWEST 5000-8000FT OF THE ATMOSPHERE
WILL FEED MOISTURE OFF THE ATLANTIC INTO CENTRAL NC THROUGH EARLY
THURSDAY...MAINTAINING THE LOW CLOUDS AND ASSOCIATED SUB VFR
CEILINGS.  IMPROVING AVIATION CONDITIONS AND A RETURN TO VFR
PARAMETERS EXPECTED BY THURSDAY.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...WSS
NEAR TERM...HARTFIELD/CBL
SHORT TERM...KRR
LONG TERM...BADGETT
AVIATION...WSS









AREA FORECAST DISCUSSION

NWS RALEIGH NC

 110 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SLOW MOVING STORM SYSTEM OVER THE MISSISSIPPI VALLEY WILL APPROACH
THE AREA SUNDAY...AND CROSS THE REGION ON MONDAY. THIS WEATHER
SYSTEM WILL BRING PERIODS OF RAIN TO CENTRAL NC TODAY THROUGH MONDAY
NIGHT.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 845 PM SATURDAY:

REST OF TONIGHT: THE DE FACTO THEME OF RECENT FORECASTS HAS BEEN TO
SLOW DOWN THE ARRIVAL OF RAIN... AS THIS INCOMING STORM SYSTEM HAS
BEEN PROGRESSING VERY SLOWLY EASTWARD... AND THE MODELS HAVE
CONTINUED TO STEADILY DELAYED PRECIP ARRIVAL FOR SEVERAL RUNS NOW.
THIS THEME MUST BE CONTINUED THIS EVENING... AS THE NEWEST
FINE-SCALE CONVECTION-ALLOWING MODEL RUNS GREATLY HOLD BACK THE
ARRIVAL OF SIGNIFICANT RAIN IN THE WESTERN CWA UNTIL CLOSE TO
DAYBREAK. ONE BROKEN BAND OF WEAKLY FORCED RAIN HAS STREAKED ACROSS
SWRN NC AND THE NC/SC BORDER IN THE LAST SEVERAL HOURS... SUPPORTED
IN PART BY SHEARING MID LEVEL VORTICITY. UPPER DIVERGENCE WILL
WEAKEN OVER NC AS A JET STREAK HEADS OFFSHORE WITH MID LEVEL RIDGING
BUILDING IN TONIGHT AHEAD OF THE INCOMING SLOW-MOVING SHORTWAVE
TROUGH OVER THE MID MISS VALLEY... LEADING TO DISSIPATION OF FORCED
ASCENT OVER NC. THE LOW LEVELS OVER THE WESTERN CWA HAVE MOISTENED
UP QUICKLY EARLY THIS EVENING BUT NOT SO IN THE NORTHEAST CWA... AND
THE RAP AND LOCAL WRF BRING THE SLIGHTLY DRIER AIR NOW OVER NE NC/SE
VA WESTWARD TONIGHT (DUE TO THE ESE SURFACE CIRCULATION AROUND THE
SURFACE HIGH CENTERED OFF DELMARVA)... A REASONABLE TRAJECTORY. WITH
THE WANING FORCING OVER NC... AND WITH THE STRONG SOUTHWESTERLY 850
MB JET THAT IS HELPING TO DRIVE THE CONVECTION OVER AL/N GA/E TN
EXPECTED TO HOLD WELL TO OUR WEST OVERNIGHT (ACCELERATING UP INTO
FAR WRN WV)... WE`RE UNLIKELY TO SEE ENOUGH OF A SURGE IN MOISTURE
OR INCREASE IN LIFT FOR ANYTHING BUT PATCHY VERY LIGHT RAIN OR
SPRINKLES UNTIL CLOSE TO SUNRISE. WILL LEAVE IN PATCHY SPRINKLES IN
THE WEST AND SOUTH FOR MUCH OF THE NIGHT... BUT WILL HOLD OFF THE
HIGHER POPS IN THE WESTERN CWA UNTIL AFTER 5 AM. THE OVERCAST MID
AND HIGH CLOUDS WILL HELP KEEP TEMPS UP OVERNIGHT... BUT ONLY SMALL
ADJUSTMENTS ARE NEEDED... LOWS NEAR 50 NORTHEAST TO MID 50S
SOUTHWEST. -GIH

THROUGH SUNDAY:
RAIN CHANCES WILL SLOWLY BUT STEADILY INCREASE FROM WEST TO EAST
THROUGH THE DAY ON SUNDAY AS THE BLOCKING RIDGE OVER THE EASTERN
SEABOARD SHIFTS OFFSHORE...ALLOWING THE UPPER TROUGH TO FINALLY
PROGRESS EASTWARD INTO THE APPALACHIANS. PWATS INCREASE TO 1.2-1.3"
LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT((2 STANDARD DEVIATIONS
ABOVE NORMAL)WITH THE EASTWARD PUSH OF SOUTHERLY 30KT LOW-LEVEL FEED
OF GULF MOISTURE INTO THE AREA. THUS...EXPECT CHANCES FOR RAIN TO
PRIMARILY BE CONFINED WEST OF HWY 1 THROUGH THE EARLY-MID AFTERNOON
BEFORE EVENTUALLY SPREADING EAST OF HWY 1 SUNDAY EVENING/NIGHT.

WIDESPREAD CLOUD COVER AND AREAL COVERAGE OF PRECIP WILL BE THE MAIN
DETERMINING FACTOR ON TEMPERATURES THROUGH THE PERIOD. OVERNIGHT LOWS
IN THE 50S EACH NIGHT. HIGHS SUNDAY...WILL BE VERY CAD
LIKE...ESPECIALLY IF RAINFALL THROUGH THE AFTERNOON IS CONFINED TO
WESTERN PORTIONS OF THE STATE. HIGHS IN THE LOWER 60S WEST TO LOWER
70S EAST.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 255 PM SATURDAY...

WIDESPREAD PRECIP WILL BE ONGOING TO START MONDAY MORNING. THIS
PRECIP WILL BE MAINLY CAUSED BY AN EASTWARD PROGRESSING UPPER
WAVE...ALTHOUGH SOME MODELS ARE ALSO HINTING AT A WEAK SURFACE WAVE
DEVELOPING...WHICH WOULD ALSO ENHANCE THE PRECIP. THE UPPER TROUGH
IS PROGGED TO BE ALMOST DIRECTLY OVERHEAD MONDAY AFTERNOON AND THEN
BE MOVING OFFSHORE BY MONDAY NIGHT. ANY RESIDUAL COOL STABLE CAD
LAYER SHOULD SCOUR OUT THROUGHOUT THE DAY ON MONDAY AS THE SURFACE
HIGH PROGRESSES FURTHER OFFSHORE AND SOUTHERLY FLOW TAKES OVER. AS A
RESULT...HAVE INCREASED TEMPS TO THE MID/UPPER 60S TO THE LOWER 70S.
IN ADDITION...WITH THE WARMER TEMPS AND THE FACT THAT THE UPPER
LEVEL TROUGH SHOULD BE RIGHT OVERHEAD DURING THE HEATING OF THE
DAY...THERE COULD BE SOME SCATTERED THUNDERSTORMS THAT DEVELOP
MONDAY AFTERNOON. AS THE UPPER LEVEL TROUGH AXIS SHIFTS EAST OF THE
REGION MONDAY NIGHT...DRIER AIR ALOFT WILL FILTER IN AND THE PRECIP
COVERAGE SHOULD DECREASE FROM WEST TO EAST MONDAY EVENING/NIGHT.
STORM TOTAL PRECIP (INCLUDING AMOUNTS THAT FALL BEFORE MONDAY) ARE
EXPECTED TO BE BETWEEN 1-2 INCHES. OVERNIGHT LOWS SHOULD GENERALLY
BE IN THE MID 50S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 255 PM SATURDAY...

STRENGTHENING SURFACE HIGH PRESSURE OVER NEW ENGLAND WILL BEGIN TO
BUILD DOWN INTO CENTRAL NC AND THEN LIKELY PERSIST THROUGH THE END
OF THE LONG TERM PERIOD. AS A RESULT...SURFACE WINDS SHOULD BE OUT
OF THE NORTHEAST FOR MUCH OF THE PERIOD AND THE AIR MASS SHOULD BE
RELATIVELY STABLE. IN ADDITION...MODELS NOW SHOW THE MID LEVEL RIDGE
GRADUALLY BUILDING DOWN TOWARDS THE MID ATLANTIC...WHICH HAD BEEN
FORECAST TO BE CENTERED OVER NORTHERN NEW ENGLAND. ALL OF THIS
SHOULD RESULT IN LESS IN THE WAY OF PRECIP COVERAGE...ESPECIALLY BY
THE MIDDLE TO END OF THE WORK WEEK WHEN IT VERY WELL COULD END UP
BEING MOSTLY DRY. TEMPS SHOULD GENERALLY BE IN THE LOW/MID 70S...
STILL SLIGHTLY BELOW NORMAL DUE TO THE COOL MOIST NORTHEASTERLY
FLOW. THERE IS STILL QUITE A BIT OF UNCERTAINTY WITH REGARDS TO OUR
NEXT SYSTEM...BUT THE BUILDING RIDGE OVER THE EAST COAST MAY HOLD IT
WEST OF THE REGION (WHILE A SOUTHERN STREAM SYSTEM IS SHUNTED TO OUR
SOUTH) UNTIL THE VERY END (OR JUST BEYOND) THE CURRENT FORECAST
PERIOD.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 110 AM SUNDAY...

VFR CONDITIONS WITH CEILINGS BETWEEN 5000-10000FT WILL OCCUR
OVERNIGHT THROUGH THE EARLY MORNING HOURS. AN INCREASING LOW LEVEL
SE FLOW WILL ADVECT ADDITIONAL MOISTURE INTO CENTRAL NC WHILE AN
AREA OF LOW PRESSURE LIFTS N-NE ACROSS THE OH VALLEY. THIS WEATHER
SYSTEM WILL BRING AREAS OF RAIN TO THE WESTERN PIEDMONT INCLUDING
KINT AND KGSO BY LATE MORNING. THIS WILL LEAD TO MVFR/IFR CEILINGS
TO THE TRIAD REGION TERMINALS BY MID DAY. THE LEADING EDGE OF THE
RAIN SHIELD WILL CREEP EWD THIS AFTERNOON AND TONIGHT...EVENTUALLY
REACHING KRDU...KRWI AND KFAY LATE THIS AFTERNOON-EARLY EVENING. THE
RAIN WILL CONTINUE TONIGHT INTO MOST OF MONDAY THEN DIMINISH FROM
THE WEST LATE MONDAY AND MONDAY NIGHT.

WHILE THE RAIN WILL END...THE MVFR-IFR CEILINGS WILL PERSIST MONDAY
NIGHT INTO TUESDAY AS MOISTURE WILL REMAIN TRAPPED BELOW A MID LEVEL
INVERSION. A NE FLOW IN THE LOWEST 5000-8000FT OF THE ATMOSPHERE
WILL FEED MOISTURE OFF THE ATLANTIC INTO CENTRAL NC THROUGH EARLY
THURSDAY...MAINTAINING THE LOW CLOUDS AND ASSOCIATED SUB VFR
CEILINGS.  IMPROVING AVIATION CONDITIONS AND A RETURN TO VFR
PARAMETERS EXPECTED BY THURSDAY.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...WSS
NEAR TERM...HARTFIELD/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...WSS






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 349 AM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECWMF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE 06 UTC TAF PERIOD WITH
SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS. GUSTY NORTHWESTERLY
WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL NORTH DAKOTA BY LATE
THIS MORNING AND SUBSIDE SHORTLY AFTER SUNSET TO BELOW 10 KTS.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LTH
LONG TERM...WAA
AVIATION...LTH
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH









AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 201 AM EDT SUN APR 28 2013

.SYNOPSIS...
A MOIST WEDGE OF COOLER AIR WILL REMAIN OVER THE REGION FOR MOST OF
TODAY AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY ALONG A
STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE COOL AIR
WEDGE WILL GRADUALLY WEAKEN BY TONIGHT. OUR WEATHER PATTERN WILL
LIKELY REMAIN UNSETTLED THROUGH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
1 AM UPDATE...REVISED THE FIRST FEW HOURS OF POPS TO REFLECT RADAR.
LLVL JET STRENGTHENING UPSTREAM AHEAD OF UPPER TROUGH AND AS THIS
MOVES EAST IT WILL SUPPORT INCREASINGLY WIDESPREAD SHOWERS.

EVENING UPDATE...NO MAJOR CHANGES ARE NEEDED TO THE GOING FCST
OVERNIGHT. THE HI-RES MODELS HAVE HANDLED THE LULL IN PRECIP AS THE
H5 S/W ENERGY HAS BEEN MUTED TRAVERSING THE RIDGE AXIS. STILL LOOKS
GOOD FOR THE WARM FRONT ADVANCING TOWARD THE AREA DURING THE DAY
TOMORROW AND LLVL MOISTURE BEING MAINTAINED WHILE ISEN LIFT
INCREASES OVERNIGHT. THIS WILL SPAWN OFF MORE -SHRA ACROSS THE SRN
ZONES TO GO ALONG WITH THE WAVES OF ENERGY CROSSING THE NRN PART OF
THE CWFA. SO...NO CHANGES TO THE CAT POPS WILL BE MADE WITH THIS
UPDATE. DON/T ANTICIPATE ANY GOOD CHANCE THUNDER AS THE LLVL WEDGE
WILL REMAIN IN PLACE AND OVERALL BROAD SCALE SUBSIDENCE WILL HOLD
VERTICAL CELL DEVELOPMENT IN CHECK AS IS SEEN WITH THE FEW SHOWERS
ADVANCING FROM THE SW ATTM.

730 PM EDT UPDATE...THE PRECIP SHIELD IS STILL BEING WELL MAINTAINED
BY CHANNELED UPPER ENERGY AND ATL/GOM MOISTURE FLUX. THE 88D IS
SHOWING SHALLOW CELLS EMBEDDED WITHIN THE BAND AND NO REAL GOOD
CHANCE OF THUNDER WITH WARM MID LEVELS UNDERNEATH THE RIDGE. POPS
WERE ADJ UP ACROSS THE NRN ZONES WHERE THE BANDING HAS SET UP. A
DECREASE IN PRECIP COVERAGE WAS ADDED IN THE GRIDS OVER THE NEXT 3
HRS BASED ON THE HRRR AND HI/RES WRF INDICATING A N/LY LIFT AND SOME
LOSS OF ULVL SUPPORT. TEMPS WERE REDUCED A LITTLE TO ACCOUNT FOR THE
AREAS COOLER THAN FCST/D DUE TO LIGHT TO CONTINUED MODERATE PRECIP.

430 PM EDT UPDATE...BUMPED UP POPS ACROSS THE LOWER NC PIEDMONT AND
UPSTATE TO ACCOUNT FOR REGION OF LIGHT TO MODERATE RAIN ASSOCIATED
WITH TRAVERSING UPPER S/W. THE MELTING LAYER IS AROUND 6.5 KFT...SO
A BRIGHT BANDING IS INDICATED ON THE DUAL POL IN RELATION TO GRAUPEL
AND MELTING SNOW. DONT ANTICIPATE VERY TALL OR LONG LIVED CELLS IN
THIS ENVIRONMENT. HOURLY TEMPS HAVE BEEN ADJ DOWN A COUPLE DEGREES
MAINLY ACROSS THE UPSTATE AS THE THICK MULTI/LAYERED CLOUDS AND
PRECIP DRAG HAS KEPT THINGS COOLER THAN FCST/D.

AS OF 230 PM...SFC LOW PRESSURE WAS ANALYZED OVER THE ARKLATX AS
HIGH PRESSURE REMAINED CENTERED OVER THE NEW ENGLAND COAST. LATEST
WV IMAGES INDICATED THAT A MID LEVEL S/W WAS RIPPLING ALONG THE
KY/TN LINE. REGIONAL RADAR SHOWS A WIDE BAND OF SHOWERS AHEAD OF THE
WAVE...WEST ALONG A WARM FRONT ASSOCIATED WITH THE LOW.
OVERNIGHT...THE SFC LOW IS FORECAST TO TRACK NE...REACHING THE
SOUTHERN OHIO RIVER VALLEY BY 12Z SUN. THE SFC PATTERN BETWEEN THE
LOW AND RIDGING HIGH PRESSURE WILL PRODUCE STRENGTHENING SE LLVL
FLOW. IN ADDITION...A RIBBON OF JET DIVERGENCE WILL REMAIN ACROSS
THE SOUTHERN APPALACHIANS OVERNIGHT. THE COMBINATION OF DEEP
MOISTURE...UPSLOPE FLOW...AND UPPER SUPPORT SHOULD SUPPORT
WIDESPREAD SHOWERS ACROSS THE MTNS TONIGHT. AREAS EAST WILL CONTINUE
TO SEE ROUNDS OF SHRA...SUPPORTED MAINLY BY INCREASING 295K
ISENTROPIC LIFT. RAINFALL OVERNIGHT MAY RANGE FROM 0.75 TO AN
INCH...WITH PIEDMONT QPF RANGING FROM .3 TO .4 TO LESS ACROSS THE
ACROSS THE LAKELANDS. LOW TEMPERATURES WILL RANGE FROM THE U40S
ACROSS THE MTNS TO L50S EAST.

SUNDAY...LLVL ISENTROPIC LIFT WILL SUPPORT WIDESPREAD COVERAGE
THROUGH THE DAY. RAINFALL RATES MAY INCREASE DURING THE AFTERNOON AS
THE MID LEVEL TROF APPROACHES. IN ADDITION...NAM CAPES POOL ACROSS
THE NE GA...UPSTATE...AND SOUTHERN NC PIEDMONT TO 300-600 J/KG. DUE
TO THE INSTABILITY AND FORCING...I WILL INCREASE THE MENTION OF
TSRA. OVERALL...POPS WILL PEAK AROUND 100 PERCENT AT SOME POINT
DURING THE DAY. QPF ON SUNDAY RANGES A LITTLE OVER AN INCH ACROSS
THE SOUTHERN ESCARPMENT TO NEAR 0.75 EAST. HIGH TEMPERATURES WILL
FEATURE A CAD PATTERN WITH U50S ACROSS THE MTNS AND MID TO UP 60S
EAST.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AS OF 240 PM SAT...THE MAIN FORCING FROM THE LIFTING TROUGH AXIS
WILL MOVE THROUGH THE FORECAST AREA SUNDAY NIGHT IN THE FORM OF DEEP
LAYER DPVA...UPPER DIVERGENCE IN THE ENTRANCE REGION OF THE JETLET
STRETCHED UP THE APPALACHIANS...AND CONTINUED MOIST UPGLIDE IN S/SW
850 MB FLOW. THERE APPEARS TO BE SOME TREND TOWARD THE BEST FOCUS OF
OVERNIGHT QPF INTO THE PIEDMONT AND AWAY FROM THE MTNS. THIS MAKES
PINNING DOWN THE HYDRO THREAT AREA WITH ENOUGH CERTAINTY FOR A WATCH
MORE PROBLEMATIC AS THE 2.5 TO 3 INCH RAINFALL SWATH MAY NOW COVER A
GOOD CHUNK OF THE AREA. WILL CONTINUE TO FEATURE THE HEAVY RAIN
THREAT IN THE HWO AND NOW HIGHLIGHT ALL AREAS...INCLUDING CHARLOTTE
METRO.

THE AXIS OF THE UPPER TROUGH WILL CROSS THE REGION ON MONDAY...WITH
GRADUAL MID LEVEL DRYING BEHIND THE FEATURE. GIVEN THE ABUNDANT
LINGERING LOW LEVEL MOISTURE AND SLIGHTLY STEEPENING LAPSE RATES
UNDER THE PASSING TROUGH...THERE SHOULD BE ENOUGH INSTABILITY FOR
DECENT SCATTERED THUNDERSTORM COVERAGE THROUGH THE AFTN
HOURS...ESPECIALLY IN PIEDMONT SECTIONS.

UPPER RIDGING WILL DEVELOP MONDAY NIGHT THROUGH TUE NIGHT...BUT WITH
AN H5 WEAKNESS OVER THE LOWER MS RIVER VALLEY. LOW LEVEL MOISTURE
WILL PERSIST...WITH LOW CLOUDS AND FOG POSSIBLY REDEVELOPING BY
DAYBREAK TUE. HOWEVER...PROFILES APPEAR MUCH MORE CAPPED TO DEEP
CONVECTION BY TUE WITH LITTLE TO NO TRIGGERING UNDER THE SHALLOW
RIDGE. LOW LEVEL EASTERLY FLOW WILL GET REESTABLISHED LATE TUE
THROUGH TUE NIGHT. TEMPS WILL GRADUALLY WARM THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 220 PM SATURDAY...THE MEDIUM RANGE REMAINS UNSETTLED...AS
PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW LEVEL MOISTURE
INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES FOR SHOWERS AND
THUNDERSTORMS. INSTABILITY WILL BE BEST IN THIS PERIOD WEDNESDAY
AFTERNOON WITH CAPES ON THE OLD ECMWF 300 TO 500 BUT VERY LOW ON THE
MOST RECENT GFS. THAT IS THE DEPICTION ON THE GFS MODEL. THE ECMWF
IS SHOWING MUCH DRIER WEATHER FOR OUR IMMEDIATE REGION NEXT WEEKEND
AS IT HAS THE CLOSED OFF 500MB LOW OVER EASTERN KANSAS. THIS MODEL
SEEMS TO NOT BE AS RELIABLE GOING INTO THE SPRING. THE GFS ON THE
OTHER HAND HAS THE DEEP UPPER LOW OVER ARKANSAS FRIDAY AND ARRIVING
OVER HUNTSVILLE AL SUNDAY MORNING. IF THE GFS VERIFIES...DIURNAL
CONVECTION WEDNESDAY AND THURSDAY...INCREASING IN COVERAGE FRIDAY
AND SATURDAY AS A SURFACE LOW DEVELOPS LATE THURSDAY OVER LA AND
PULLS A WARM FRONT FROM AL TO THE CAROLINAS FRI AND SAT. AS THE WARM
FRONT PASSES ON SATURDAY...THE LOW LEVEL WIND FLOW WILL SWITCH
AROUND FROM EASTERLY TO WEST.  THE AREA NEAR THE WARM FRONT LOOKS TO
BE A GOOD ZONE OF LOW LEVEL CONVERGENCE AND THE 6 HOUR PRECIP ON THE
GFS INDICATES NEAR A THIRD TO A HALF INCH. AFTER SAYING
THIS...CONFIDENCE IN THE EVENTUAL OUTCOME A WEEK FROM NOW IS LOW AND
PREFER TO BE CONSERVATIVE WITH THE POP FORECAST KEEPING IT LOW IN
THE SLIGHT TO LOW CHANCE. TEMPERATURES WILL BE BELOW NORMAL FOR
HIGHS AND ABOVE NORMAL FOR LOWS EARLY IN PERIOD THEN DROPPING BELOW
NORMAL NEXT WEEKEND AS THE UPPER LOW COMES OVER OUR REGION.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT...COLD WEDGE IN CONTROL INITIALLY FOR THE PERIOD...
MAINTAINING EASTERLY WINDS. VFR CIGS WILL LOWER OVER THE NEXT FEW
HRS AS UPPER FORCING CROSSES AND ENHANCES LIFT FROM WARM ADVECTION
OVER THE WEDGE...WITH SHOWERS ALSO INCREASING IN COVERAGE TOWARD
DAWN. GUIDANCE PRETTY SOLID WITH CIGS DROPPING TO MVFR AND REMAINING
THERE THRU MORNING. STILL BETTER FORCING ARRIVES BY AFTERNOON...WITH
THE WEDGE BEGINNING TO BREAK DOWN AND ALLOWING SOME BETTER
INSTABILITY TO WORK IN. HENCE PROB30 TSRA WITH IFR VSBY FOR THE
AFTERNOON. DESPITE THE POSSIBLE EROSION OF THE WEDGE...STILL
PLENTIFUL LLVL MOISTURE WILL ALLOW IFR CIGS TONIGHT.

ELSEWHERE...AHEAD OF PROMINENT UPPER SHORTWAVE TROUGH MIDLEVEL WINDS
WILL RAMP UP THRU THE FIRST FEW HOURS OF THE TAF PERIOD. INCREASING
SHOWER ACTIVITY WILL INITIALLY BE SEEN IN THE WESTERN HALF OF THE
FCST AREA BEFORE SPREADING EAST BY DAYBREAK. PRECIP GENERALLY
EXPECTED TO DROP VSBY TO MVFR BUT WITH THE ENHANCED LIFT CIGS WILL
BE ABLE TO DROP TO IFR ACROSS PORTIONS OF THE AREA AROUND 12Z. SOME
IMPROVEMENT MAY BE SEEN DURING THE DAY AS THE COLD WEDGE OVER THE
REGION BEGINS TO ERODE LIMITING THE LLVL FORCING FOR CLOUDS/PRECIP.
HOWEVER RESTRICTIONS OF AT LEAST MVFR ARE LIKELY TO CONTINUE THRU
THE PERIOD WITH LLVL MSTR PROFILES STAYING SATURATED. CURRENTLY
EXPECT MANY SITES TO HIT IFR THRESHOLD AFTER 00Z MON.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            06-12Z        12-18Z        18-24Z        00-06Z
KCLT       HIGH  94%     MED   75%     HIGH  83%     HIGH  96%
KGSP       HIGH  89%     MED   62%     HIGH  82%     HIGH  97%
KAVL       HIGH  91%     HIGH  92%     HIGH  88%     HIGH  86%
KHKY       MED   74%     LOW   56%     HIGH  81%     HIGH  98%
KGMU       MED   71%     MED   62%     MED   72%     HIGH  92%
KAND       MED   73%     LOW   52%     MED   65%     HIGH  80%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...DEO
NEAR TERM...NED/SBK/WIMBERLEY
SHORT TERM...HG
LONG TERM...DEO
AVIATION...WIMBERLEY







WEATHER FORECAST DISCUSSION.



 GIVEN RELATIVE LACK OF MOISTURE BELOW ABOUT 600MB...THINK CHANCE OF
CONVECTION DEVELOPING ALONG THE BOUNDARY WILL INITIALLY BE QUITE LOW
AND HAVE KEPT MOST AREAS DRY UNTIL THE LATE AFTERNOON/EVENING...AS
THE BOUNDARY MOVES INTO SLIGHTLY BETTER MOISTURE NEAR/SOUTHEAST OF
HIGHWAY 60 CORRIDOR IN NORTHWEST IOWA/SOUTHWEST MINNESOTA. DO NOT
ANTICIPATE ANY SEVERE WEATHER DURING THIS TIME...ALTHOUGH WITH THE
INITIALLY DRY SUB-CLOUD LAYER WOULD NOT BE SURPRISED TO SEE SOME
WIND GUSTS IN THE 40-50MPH RANGE. THIS ACTIVITY SHOULD FOLLOW THE
FRONT SOUTHWARD THROUGH THE EVENING...WITH RAIN CHANCES INCREASING
FROM THE SOUTHWEST IN THE LATE EVENING/OVERNIGHT AS SHORTWAVE MOVES
EAST ALONG STRENGTHENING MID LEVEL FRONT IN OUR FAR SOUTHERN CWA.
THIS ACTIVITY SHOULD BE FAIRLY QUICK MOVING AND LIGHT...WITH THE
SHORTWAVE EXITING THE CWA TOWARD 12Z MONDAY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 458 AM CDT SUN APR 28 2013

SOMEWHAT MORE UNSETTLED PATTERN DEVELOPING ACROSS THE REGION THIS
WEEK...AS GENERALLY ZONAL FLOW ALOFT TRANSITIONS TO BROAD TROUGH
OVER THE WESTERN CONUS THROUGH THE EARLY PART OF THE WEEK...AND
EVENTUALLY TO A CUTOFF UPPER LOW OVER THE CENTRAL PLAINS BY THE
LATTER PART OF THE WEEK. ONE SHORTWAVE SLIDING THROUGH THE BASE OF
THE TROUGH ALONG THE CANADIAN BORDER MONDAY NIGHT. FRONTAL BOUNDARY
WHICH PUSHES THROUGH US TODAY WILL LIFT BACK TO THE NORTH ON MONDAY
AHEAD OF THIS WAVE...THEN MOVE SOUTHEAST ACROSS THE FORECAST AREA
WITH A STRONGER PUSH OF COOLER AIR LATE MONDAY NIGHT AND TUESDAY.
MONDAY SHOULD BE ANOTHER MILD DAY...THOUGH NOT QUITE AS WARM AS THE
WEEKEND IN MOST AREAS WITH WARMEST LOW LEVEL AIR NOT SPREADING INTO
THE AREA UNTIL MONDAY LATE AFTERNOON/EVENING. STILL LOOKING AT HIGHS
IN THE UPPER 60S AND 70S THOUGH.

LOW LEVEL JET AHEAD OF THE BOUNDARY COULD TRIGGER A FEW HIGH BASED
SHOWERS OR STORMS IN OUR FAR NORTHERN CWA MONDAY NIGHT...THOUGH
BETTER CHANCE OF THIS LOOKS TO REMAIN NORTH OF THE AREA WITH BETTER
UPPER FORCING THROUGH NORTH DAKOTA/NORTHERN MINNESOTA.

COLD ADVECTION THROUGH THE DAY TUESDAY...THOUGH MIXY WITH STOUT
NORTHERLY FLOW BEHIND THE FRONT SO STILL POTENTIAL TO SEE NEAR
NORMAL HIGHS FOR THE LAST DAY OF APRIL. CURRENT THINKING ON TIMING
OF THE FRONT PUTS IT SOUTHEAST OF OUR FORECAST AREA BY MIDDAY WITH
850MB FRONT NOT FAR BEHIND. THIS SHOULD LIMIT ANY PRECIP THREAT IN
OUR AREA DURING THE DAY. RAIN CHANCES DRAMATICALLY INCREASE TUESDAY
NIGHT AND WEDNESDAY AS MAIN UPPER TROUGH BEGINS TO SWING OUT OF THE
ROCKIES. GOOD MODEL CONSENSUS PLACING A STRONG MID LEVEL FRONT OVER
THE SOUTHEAST HALF OF OUR FORECAST AREA BY 06Z WEDNESDAY...WITH THE
MID LEVEL BOUNDARY THEN JUST SLOWLY SHIFTING EASTWARD THROUGH THE
DAY WEDNESDAY. HAVE BUMPED POPS INTO HIGHER LIKELY RANGE FOR THESE
PERIODS. STRONGEST PUSH OF COLD AIR WILL FOLLOW THIS BOUNDARY INTO
THE REGION...WITH 850MB AND EVEN 925MB TEMPERATURES BELOW FREEZING
BY WEDNESDAY AFTERNOON. WITH JUST A SHALLOW NEAR-SURFACE LAYER ABOVE
FREEZING...RAIN/SNOW MIX QUITE POSSIBLE IN SOME AREAS...AND WILL
KEEP MENTION OF RAIN/SNOW MIX RIGHT THROUGH THURSDAY NIGHT AS ANY
SURFACE-BASED WARM LAYER REMAINS QUITE SHALLOW.

MODELS HAVE COME INTO SOMEWHAT BETTER AGREEMENT IN HANDLING UPPER
LOW AS IT DIGS INTO THE SOUTHERN PLAINS AND CUTS OFF FROM THURSDAY
ON. STILL SOME FINE DETAILS SHOWING DISAGREEMENT...LIKE EXACT
POSITIONING AND AMOUNT OF MOISTURE WRAPPING AROUND THE NORTH SIDE OF
THE CUTOFF INTO OUR FORECAST AREA. DEPENDING ON TIMING... COULD SEE
A DRIER PERIOD OVER MUCH OF THE AREA THURSDAY THROUGH FRIDAY...
THOUGH ENOUGH UNCERTAINTY THAT HAVE KEPT CHANCE POPS IN MAINLY THE
EASTERN HALF OF THE CWA THROUGH THIS TIME. CHANCES LOOK TO INCREASE
AGAIN SATURDAY AS BOTH ECMWF AND GFS BEGIN TO SWING THE UPPER LOW
NORTHWARD THROUGH THE CENTRAL PLAINS.

WITH RE-ENTRY INTO WELL BELOW NORMAL REGIME FOR THE LATTER HALF OF
THE WEEK...HAVE LOWERED FORECAST HIGHS FROM WEDNESDAY ON CLOSER TO
RAW MODEL OUTPUT...AS NUMERICAL GUIDANCE IS AGAIN SHOWING STRONGER
INFLUENCE FROM MUCH WARMER CLIMATOLOGY VALUES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1020 PM CDT SAT APR 27 2013

VFR EXPECTED THROUGH 06Z MONDAY. A WEAK COLD FRONT WILL PUSH EAST
ACROSS THE AREA LATE TONIGHT AND SUNDAY. SCATTERED THUNDERSTORMS MAY
DEVELOP NEAR THIS FRONT ALONG AND EAST OF INTERSTATE 29 AFTER 22Z
SUNDAY.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$

SHORT TERM...JH
LONG TERM...JH
AVIATION...







AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 359 AM CDT SUN APR 28 2013

.DISCUSSION...

REGIONAL RADAR MOSAIC SHOWS A BROAD AREA OF CONVECTION EXTENDING
FROM BRYAN SOUTHWEST ALONG THE TX GULF COAST TO CORPUS CHRISTI
EARLY THIS MORNING. 08Z /3AM/ SURFACE OBSERVATIONS SHOWED A
DIFFUSE FRONTAL BOUNDARY LOCATED JUST SOUTHEAST OF A LINE FROM
TEMPLE TO PALESTINE. THE BOUNDARY WAS MOST EVIDENT IN THERMAL AND
MOISTURE FIELDS AS LOW LEVEL WINDS HAVE ALREADY STARTED TO COME
AROUND TO THE SOUTHEAST TO THE NORTH OF THE FRONT. WATER VAPOR
SATELLITE IMAGERY SHOWED A COMPACT UPPER LOW OVER THE IN/IL BORDER
MOVING EAST-NORTHEAST EARLY THIS MORNING. WATER VAPOR IMAGERY ALSO
SHOWED A CYCLONIC SHEAR AXIS OR TROUGH TRAILING BEHIND THE UPPER
LOW TO THE SOUTHWEST. THIS TROUGH WAS LOCATED OVER THE CWA AS OF
08Z AND WAS MOVING SLOWLY SOUTHEAST. ALONG THE DIFFUSE FRONTAL
BOUNDARY...IR SATELLITE IMAGERY SHOWED MOSTLY CLOUDY SKIES WHICH
WAS HELPING TO KEEP TEMPERATURES IN THE LOWER TO MID 60S NEAR THE
FRONT. TO THE NORTHWEST OF THE FRONT THERE WAS A SHARP CUT-OFF IN
CLOUD COVER...ALLOWING TEMPERATURES TO FALL INTO THE 50S FOR MOST
OF NORTH TX EARLY THIS MORNING.

TODAY...THE UPPER LEVEL TROUGH IS EXPECTED TO SLOWLY MOVE
SOUTHEAST OF THE CWA TODAY...SPREADING WEAK LARGE SCALE FORCING
FOR SUBSIDENCE OVER THE AREA. SURFACE WINDS ARE EXPECTED TO RETURN
TO THE SOUTH TODAY WHICH MAY CAUSE THE WEAK FRONTAL BOUNDARY TO
LIFT NORTH ACROSS THE CWA THIS AFTERNOON. IT IS DIFFICULT TO
DETERMINE IF THIS WILL BE OF ANY CONSEQUENCE... BECAUSE THE RETURN
TO SOUTH WINDS UNDER MOSTLY SUNNY SKIES WILL MORE OR LESS
ELIMINATE ANY THERMAL GRADIENT/BAROCLINICITY ASSOCIATED WITH THE
FRONT.

BY DEFINITION THIS BOUNDARY WOULD NOT COUNT AS A FRONT ANYMORE
WITHOUT A DISCERNABLE THERMAL GRADIENT. HOWEVER...THERE WILL STILL
BE SOME SORT OF MOISTURE DISCONTINUITY ASSOCIATED WITH THE
BOUNDARY AS IT LIFTS NORTH TODAY...LIKELY RESULTING IN A SLIGHT
INCREASE IN RELATIVE HUMIDITY. NORMALLY THIS WOULD HAVE LITTLE
IMPACT ON THE FORECAST...BUT TODAY THE NAM AND RAP FORECAST
SOUNDINGS INDICATE THAT THE AFTERNOON INCREASE IN LOW-LEVEL
HUMIDITY IS SUFFICIENT TO RESULT IN AN ALMOST COMPLETE REMOVAL OF
THE CAP FROM THE FORECAST AREA DURING THE PEAK HEATING HRS OF THE
DAY. WITH NO CAP...IT IS POSSIBLE THAT SOME WEAK FORCING FOR
ASCENT COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS NORTH TX BY
LATE THIS AFTERNOON.

AT THIS TIME...LEFT THE FORECAST DRY BECAUSE OF A LACK OF
DISCERNABLE FOCUS FOR THUNDERSTORM INITIATION THIS AFTERNOON. THE
SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH IS EXPECTED TO BE
WEAK...BUT IN THE ABSENCE OF STRONG MESOSCALE FORCING FOR
ASCENT...THIS SHOULD BE SUFFICIENT TO KEEP US DRY DESPITE A NEARLY
UNCAPPED AFTERNOON THERMODYNAMIC ENVIRONMENT. OTHERWISE...WITH
MOSTLY SUNNY SKIES AND A RETURN TO SOUTH WINDS TODAY EXPECT
TEMPERATURES TO CLIMB INTO THE 80S FOR MOST LOCATIONS DESPITE THE
COOL START TO THE DAY THIS MORNING.

MONDAY AND TUESDAY...THE ECMWF/GFS/CANADIAN NOW ALL SHOW THE THAT
THE WESTERN EDGE OF OUR SOUTHEASTWARD MOVING TROUGH TODAY EVOLVES
INTO AN UPPER LEVEL CLOSED LOW OVER THE TX GULF COAST MONDAY INTO
TUESDAY. THIS WEAK UPPER LOW WILL LIKELY CAUSE CLUSTERS OF STORMS
TO DEVELOP EACH DAY ACROSS FAR SOUTH TX OR ALONG THE TX GULF
COAST...LIKELY WORKING TO REINFORCE THE UPPER LEVEL CIRCULATION
THROUGH THE PERIOD. DUE TO THE FORECAST POSITION OF THE UPPER LOW
TO OUR SOUTH...THIS FEATURE SHOULD ONLY REINFORCE UPPER LEVEL
SUBSIDENCE OVER THE CWA HELPING TO KEEP US DRY FOR EARLY THIS
WEEK. PERSISTENT SOUTHERLY FLOW WILL CONTINUE CAUSING SHALLOW GULF
MOISTURE TO REMAIN IN PLACE OVER THE CWA...BUT THUNDERSTORM
CHANCES SHOULD BE VERY LOW AS LONG AS THE UPPER LOW OVER THE GULF
COAST EVOLVES AS EXPECTED. AT ANY RATE...MOSTLY SUNNY SKIES AND
PERSISTENT SOUTHERLY FLOW WILL KEEP US ABOVE NORMAL FOR
TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S EACH DAY.

WEDNESDAY THROUGH FRIDAY...A POWERFUL UPPER LOW FROM THE GULF OF
ALASKA IS STILL EXPECTED TO MOVE SOUTHEAST OVER THE PLAINS
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SEND AN UNSEASONABLY
STRONG COLD FRONT SOUTH THROUGH THE PLAINS AND ACROSS NORTH TEXAS
LIKELY WEDNESDAY EVENING AND OVERNIGHT. AS LONG AS THE UPPER LOW
DIGS AS FAR SOUTH AS THE RED RIVER...WHICH IS ADVERTISED BY THE
OPERATIONAL ECMWF/GFS/CANADIAN...THERE SHOULD BE A NEARLY SOLID
LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANYING THE FRONT. THE FRONT
IS EXPECTED TO MOVE THROUGH THE AREA VERY FAST...SO OVERALL
RAINFALL AMOUNTS WILL LIKELY BE SMALL...BUT MOST LOCATIONS SHOULD
AT LEAST SEE SOME LIGHT RAIN AS THE FRONT MOVES THROUGH THE AREA.
BUMPED UP POPS INTO THE 40 TO 50 PERCENT RANGE ALONG AND BEHIND
THE FRONT AS A RESULT. DID NOT GO HIGHER AT THIS TIME BECAUSE OF
UNCERTAINTY REGARDING THE TIMING OF THE FRONT. WHILE OPERATIONAL
MODELS ARE CONSISTENT WITH THE FRONTAL PASSAGE RIGHT NOW...THE
FRONT IS STILL AT LEAST 84 HRS OUT...AND OUR MEDIUM RANGE GUIDANCE
IS NOTORIOUSLY BAD AT PREDICTING THE TIMING OF STRONG COLD FRONTS.
THEREFORE WILL CONTINUE TO REFINE POPS AND THE TIMING OF THE FRONT
IN FUTURE FORECASTS.

SEVERE WEATHER CHANCES OUT AHEAD OR ALONG THE FRONT DO NOT LOOK
GREAT PRIMARILY BECAUSE OF THE PROGGED FAST MOTION OF THE FRONT
THROUGH THE PLAINS. SOME SEVERE WEATHER MAY BE ADDED TO THE
FORECAST AS THE FRONT GETS CLOSER...BUT FOR NOW THE OVERALL
PATTERN DOES NOT SEEM TO SUPPORT A REGIONAL OUTBREAK OF SEVERE
STORMS...SO WILL NOT HIGHLIGHT ANY SEVERE WEATHER IN PRODUCTS AT
THIS TIME. TEMPERATURES BEHIND THE FRONT ARE EXPECTED TO BE VERY
COLD FOR EARLY MAY...WITH RECORD LOW TEMPERATURES LIKELY BEHIND
THE FRONT THURSDAY NIGHT. RECORD LOWS THURSDAY NIGHT WILL HELP
KEEP TEMPERATURES COOL HEADED INTO THE WEEKEND.

THIS WEEKEND...THE ECMWF IS LESS BULLISH WITH ITS FORECAST OF A
BLOCKING PATTERN THAT WOULD KEEP THE UPPER LOW ANCHORED IN THE
CENTRAL PLAINS FOR SEVERAL DAYS. THE NAEFS IS ALSO LEANING MORE
TOWARDS THE UPPER LOW MOVING NORTHEAST OUT OF THE REGION BY EARLY
NEXT WEEK. THAT SAID...THE NAEFS MEAN AND THE LAST EVENING RUN OF
THE ECMWF BOTH KEEP GENERAL TROUGHINESS OVER THE CENTRAL
CONUS...MEANING TEMPERATURES WILL LIKELY BE NEAR OR MAYBE SLIGHTLY
BELOW SEASONAL NORMALS. AFTER NEAR RECORD OR RECORD LOWS THURSDAY
NIGHT/FRIDAY MORNING...THERE IS LITTLE PLACE FOR THE TEMPERATURES
TO GO BUT UP. TEMPERATURES WILL MODERATE BACK TOWARDS SEASONAL
NORMALS THIS WEEKEND INTO EARLY NEXT WEEK...AND NOT JUST BECAUSE
MOS GUIDANCE TRENDS TOWARDS CLIMATOLOGY OUT ON DAY 7. THICKNESS
AND HEIGHT RISES WILL HELP USHER IN WARMER TEMPERATURES AS LONG AS
THE UPPER LOW DOES MOVE NORTHEAST OF THE PLAINS BY EARLY NEXT
WEEK. THE EXTENDED FORECAST IS DRY FOR NOW...HOWEVER WITH GENERAL
CYCLONIC FLOW IN PLACE THERE WILL UNDOUBTEDLY BE SOME SMALL
FEATURES THAT NECESSITATE THE INCLUSION OF PRECIPITATION DURING
THIS PERIOD IN FUTURE FORECASTS. AT THIS TIME THERE IS JUST NOT
ENOUGH CONSISTENCY TO PLACE POPS IN ONE PERIOD OVER ANOTHER...SO
LEFT THE FORECAST DRY WITH 10 POPS IN PLACE FOR SEVERAL DAYS.

CAVANAUGH

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  84  61  86  63  87 /  10   0   0   0   5
WACO, TX              84  58  84  60  86 /  10   0   0   0   5
PARIS, TX             79  55  83  58  84 /  10   0   0   0   5
DENTON, TX            83  58  87  59  87 /  10   0   0   0   5
MCKINNEY, TX          82  58  84  60  86 /  10   0   0   0   5
DALLAS, TX            83  62  86  64  87 /  10   0   0   0   5
TERRELL, TX           82  57  83  59  84 /  10   0   0   0   5
CORSICANA, TX         82  58  83  59  84 /  10   0   0   0  10
TEMPLE, TX            83  57  83  59  85 /  10   5   0   0   5
MINERAL WELLS, TX     83  58  86  59  87 /  10   0   0   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$







AREA FORECAST DISCUSSION

NWS LINCOLN IL

 1040 AM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 1038 AM CDT SUN APR 28 2013
LOW CENTER IN EAST CENTRAL INDIANA THIS MORNING...WITH LOW
STRATUS...DRIZZLE...AND COOL TEMPERATURES DOMINATING CENTRAL
ILLINOIS. WESTERN EDGE OF THE LOWEST CEILINGS ERODING SLOWLY ON
VIS AND IR SAT IMAGERY. MISS RIVER VALLEY NORTH OF QUINCY UNDER
MOSTLY SUNNY SKIES. WATCHING SUNNY SKIES BUILD SLOWLY
EASTWARD...NW OF THE ILLINOIS RIVER VALLEY LIKELY TO SEE SOME SUN
AND MAX TEMPS IN UPPER 60S/NEAR 70 AS A RESULT. FURTHER TO THE
EAST CLOSER TO THE LOW...A BIT MORE PROBLEMATIC. NOT ANTICIPATING
A SIGNIF LOSS OF CLOUD COVER...AND KEEPING COOLER TEMPS IN AS A
RESULT. SOME MINOR ADJUSTMENTS TO THE FORECAST AND THE HOURLY
GRIDS...THOUGH REISSUANCE NOT ANTICIPATED UNTIL MAYBE AFTER NOON
TO CLEAN UP SOME MORNING WORDING.


HJS
&&

.AVIATION...
ISSUED 618 AM CDT SUN APR 28 2013

LIFR CONDITIONS WILL LINGER EARLY THIS MORNING...BEFORE CEILINGS
SLOWLY BEGIN TO IMPROVE. NAM FORECAST SOUNDINGS SUGGEST CLOUD BASES
WILL RISE ABOVE 500FT BY 14/15Z...THEN INTO THE MVFR CATEGORY
AROUND 1500FT TOWARD MIDDAY. AS LOW PRESSURE RESPONSIBLE FOR THE
CLOUDS/SHOWERS PULLS FURTHER AWAY...SKIES WILL GRADUALLY CLEAR
FROM WEST TO EAST ACROSS THE AREA LATE THIS AFTERNOON INTO THE
EVENING. NAM/GFS RH PROFILES INDICATE CEILING SCATTERING AT KPIA
BY 22Z...THEN FURTHER EAST TO KCMI BY AROUND 01Z. WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS EXPECTED OVERNIGHT...BIG QUESTION WILL
BE HOW MUCH FOG DEVELOPS. NUMERIC GUIDANCE DOES NOT REDUCE VISBYS
APPRECIABLY...HOWEVER GIVEN AMPLE LOW-LEVEL MOISTURE DUE TO THE
RECENT RAINFALL AND THE FACT THAT MUCH OF THE AREA WILL NOT CLEAR
TODAY...THINK FOG WILL BE A GOOD BET. HAVE HIT VISBYS HARDEST
EAST OF THE ILLINOIS RIVER...WHERE 2 TO 3SM WILL BE COMMON.
FURTHER WEST AT KPIA...DRIER LOW-LEVEL PROFILE WILL YIELD LESSER
RESTRICTIONS DOWN TO AROUND 5SM.

BARNES
&&

.PREV DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN
MO LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND
STL. 00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS
VALLEY AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION
EAST OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE
TO PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX
OUT OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

LONG TERM...WEDNESDAY THROUGH SUNDAY...
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER
WAVE MOVING THROUGH THE GREAT LAKES TUESDAY NIGHT DRAGS A FRONT
INTO THE MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS
PROGGED TO DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE
SOUTHERN PLAINS. THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER
VALLEY FROM WED NIGHT INTO THE WEEKEND WITH SCATTERED PCPN ALONG
THE SYSTEM. MODELS HAVE BECOME A LITTLE MORE CONSISTENT AND IN
AGREEMENT WITH THIS SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF
INTO THE PLAINS AND PCPN IN THE MS VALLEY. BY THE WEEKEND...THE
SYSTEM STARTS TO MOVE OUT...HOWEVER THE TIMING ON THIS WILL STILL
NEED TO BE WATCHED. TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT
END OF WEEK IS COOLER THEN THE BEGINNING OF THE WEEK. WENT WITH
CHC POPS AS DETAILS ON THE EXACT POSITION OF THE FRONT AND UPPER
SYSTEM STILL A LITTLE UNCERTAIN.

GOETSCH


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS LINCOLN IL

 618 AM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN MO
LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND STL.
00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS VALLEY
AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION EAST
OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE TO
PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX OUT
OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

.LONG TERM...WEDNESDAY THROUGH SUNDAY.
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER WAVE
MOVING THROUGH THE GREATLAKES TUESDAY NIGHT DRAGS A FRONT INTO THE
MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS PROGGED TO
DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE SOUTHERN PLAINS.
THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER VALLEY FROM WED NIGHT
INTO THE WEEKEND WITH SCATTERED PCPN ALONG THE SYSTEM. MODELS HAVE
BECOME A LITTLE MORE CONSISTENT AND IN AGREEMENT WITH THIS
SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF INTO THE PLAINS AND
PCPN IN THE MS VALLEY. BY THE WEEKEND...THE SYSTEM STARTS TO MOVE
OUT...HOWEVER THE TIMING ON THIS WILL STILL NEED TO BE WATCHED.
TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT END OF WEEK IS COOLER
THEN THE BEGINNING OF THE WEEK. WENT WITH CHC POPS AS DETAILS ON THE
EXACT POSITION OF THE FRONT AND UPPER SYSTEM STILL A LITTLE
UNCERTAIN.

GOETSCH


&&

.AVIATION...
ISSUED 618 AM CDT SUN APR 28 2013

LIFR CONDITIONS WILL LINGER EARLY THIS MORNING...BEFORE CEILINGS
SLOWLY BEGIN TO IMPROVE. NAM FORECAST SOUNDINGS SUGGEST CLOUD BASES
WILL RISE ABOVE 500FT BY 14/15Z...THEN INTO THE MVFR CATEGORY
AROUND 1500FT TOWARD MIDDAY. AS LOW PRESSURE RESPONSIBLE FOR THE
CLOUDS/SHOWERS PULLS FURTHER AWAY...SKIES WILL GRADUALLY CLEAR
FROM WEST TO EAST ACROSS THE AREA LATE THIS AFTERNOON INTO THE
EVENING. NAM/GFS RH PROFILES INDICATE CEILING SCATTERING AT KPIA
BY 22Z...THEN FURTHER EAST TO KCMI BY AROUND 01Z. WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS EXPECTED OVERNIGHT...BIG QUESTION WILL
BE HOW MUCH FOG DEVELOPS. NUMERIC GUIDANCE DOES NOT REDUCE VISBYS
APPRECIABLY...HOWEVER GIVEN AMPLE LOW-LEVEL MOISTURE DUE TO THE
RECENT RAINFALL AND THE FACT THAT MUCH OF THE AREA WILL NOT CLEAR
TODAY...THINK FOG WILL BE A GOOD BET. HAVE HIT VISBYS HARDEST
EAST OF THE ILLINOIS RIVER...WHERE 2 TO 3SM WILL BE COMMON.
FURTHER WEST AT KPIA...DRIER LOW-LEVEL PROFILE WILL YIELD LESSER
RESTRICTIONS DOWN TO AROUND 5SM.

BARNES
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS DODGE CITY KS

 702 AM CDT SUN APR 28 2013

...UPDATED AVIATION SECTION FOR 12Z TAFS...

.SYNOPSIS...
ISSUED AT 400 AM CDT SUN APR 28 2013

SPLIT FLOW WAS IN PLACE ACROSS NORTH AMERICA WITH THE MAIN JET
ENERGY MOVING ACROSS WESTERN KANSAS AND THE PACIFIC NORTHWEST
REGION. ANOTHER UPPER JET AXIS WAS MOVING ACROSS MEXICO AND THE
SOUTHERN UNITED STATES. THE SYNOPTIC SCALE UPPER TROUGH WAS
POSITIONED ACROSS IOWA AND MISSOURI, WITH THE 850 MB EXTENDING
FARTHER SOUTH ACROSS THE SOUTHERN MISSISSIPPI VALLEY BASED ON THE 00
UTC SUBJECTIVE ANALYSIS. FARTHER WEST, A LARGE THERMAL GRADIENT
EXISTED ACROSS KANSAS INTO THE CENTRAL AND SOUTHERN ROCKIES AS 850
MB TEMPERATURES WERE AROUND 20 DEGREES C FROM RAP TO LBF, DDC AND
AMA. SURFACE TEMPERATURES ACROSS WESTERN KANSAS REMAINED MILD
THROUGH THE OVERNIGHT, RANGING FROM THE UPPER 40`S TO LOW 50`S
THROUGH AROUND 2 AM.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE MODELS DEVELOP A DRYLINE SHIFTING ACROSS THE AREA LATER TODAY
AS WEAK VERTICAL MIXING DEVELOPS. HOWEVER, LIGHT BOUNDARY LAYER
WINDS ARE IN PLACE AND LITTLE IF ANY GUSTING SEEMS POSSIBLE. THE
FULL AVAILABLE LATE APRIL INSOLATION WILL HELP TEMPERATURES SOAR IN
THE LATE MORNING AND EARLY AFTERNOON. MODELS ACROSS THE BOARD
FORECAST HIGHS IN THE MID TO UPPER 80`S FOR THIS AFTERNOON. THERE
DOES APPEAR TO BE A RAPID INCREASE IN SURFACE BASED CAPE ACROSS
CENTRAL KANSAS DURING THE LATE AFTERNOON. HOWEVER THE MODELS WORK
DRIER AIR FARTHER EAST INTO CENTRAL KANSAS IN THE AFTERNOON,
RELEGATING THE BEST SURFACE BASED CONVECTIVE AVAILABLE ENERGY
FARTHER EAST ACROSS EASTERN KANSAS. WITHOUT ANY UPPER SUPPORT, AND
LIMITED TO NONEXISTENT SBCAPE, EVEN ISOLATED STORMS DO NOT LOOK
LIKELY LATER TODAY.

WITH EXPECTED GOOD RADIATIONAL COOLING AND A RETREATING DRYLINE,
ANOTHER MILD NIGHT CAN BE EXPECTED. LOWS WILL REACH THE 40`S OVER
MOST OF SOUTHWEST KANSAS, TO LOW 50`S OVER THE CENTRAL SECTIONS.


.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CDT SUN APR 28 2013

THE LONG TERM FORECAST FOR THE MIDDLE AND LATTER PORTION OF THE WEEK
IS FRAUGHT WITH CHALLENGES AS A DEEP TROUGH DEVELOPS AND A CLOSED
LOW FORMS OUT OF THE TROUGH...EVENTUALLY BECOMING CUT OFF FROM THE
MAIN POLAR JET STREAM FLOW. PRIOR TO THE STORM SYSTEM
DEVELOPMENT...TEMPERATURES WILL SOAR INTO THE UPPER 80S TO NEAR 90
BOTH MONDAY AND TUESDAY. A LEAD SHORTWAVE MOVING EAST ACROSS THE
DAKOTAS MONDAY WILL PUSH A SUBTLE FRONTAL BOUNDARY SOUTHWARD WHICH
COULD PREVENT AREAS NORTH OF HIGHWAY 96 FROM WARMING WELL INTO THE
80S LIKE THE SOUTHERN COUNTIES.  WILL BE HEDGING COOLER IN THE
FORECAST FOR THIS REASON UP NORTH...ESPECIALLY WAKEENEY TO HAYS. ON
TUESDAY...THE ECMWF SHOWS A 992MB SURFACE LOW OVER SOUTHEASTERN
COLORADO WITH A DRYLINE TAKING SHAPE EAST OF THE LOW. THE LEAD
FRONTAL BOUNDARY WILL LIKELY PUSH NORTH LATE MONDAY NIGHT INTO EARLY
TUESDAY BEFORE MOVING BACK SOUTH DURING THE DAY TUESDAY.
AGAIN...THIS WILL LEAD TO QUITE THE CHALLENGE IN HIGH TEMPERATURE
FORECAST. FEEL PRETTY CONFIDENT, THOUGH, THAT SOME 90-92 DEGREE
TEMPERATURES WILL BE FOUND SOUTHWEST OF A JOHNSON TO ASHLAND LINE.

EVEN THOUGH THERE ARE SOME 15-20 POPS IN THE FORECAST UP IN CENTRAL
KANSAS (ELLIS-RUSH COUNTIES) LATE IN THE DAY TUESDAY...THE FEELING
IS THAT CONVECTION WILL HOLD OFF UNTIL TUESDAY EVENING AND
ESPECIALLY DURING THE NIGHT. ADVANCE OF 58 TO 61F DEWPOINTS INTO
SOUTH CENTRAL AND CENTRAL KANSAS AND VERY WARM SURFACE TEMPERATURES
WILL LEAD TO 2000 TO 2500 J/KG OF CAPE TUESDAY EVENING. THE PROBLEM
IS THAT THE 800-700MB LAYER WILL BE EXTREMELY WARM LIKELY PREVENTING
SURFACE BASED CONVECTION ON THE DRYLINE SOUTH OF THE FRONT. THE MOST
LIKELY SCENARIO IS CONVECTION FORMING AT THE NOSE OF A DEVELOPING
LOW LEVEL JUST JUST AFTER SUNSET...AND THIS IS WHEN POPS WILL
INCREASE IN THE FORECAST TO 30 TO 40 PERCENT...ESPECIALLY ALONG AND
NORTH OF HIGHWAY 96.

SOMETIME AFTER MIDNIGHT TUESDAY NIGHT...THE TRUE COLD AIR WILL BE
CHARGING SOUTH THROUGH NEBRASKA AND INTO KANSAS AS THE DEEP UPPER
TROUGH APPROACHES. TEMPERATURES IN THE 50S AND LOWER 60S WILL BE
COMMON OVERNIGHT AHEAD OF THE FRONT. THE QUESTION IS TIMING AND WILL
HAVE A HUGE IMPACT ON DAYTIME TEMPERATURES WEDNESDAY ACROSS
SOUTHWEST AND SOUTH CENTRAL KANSAS. AT THIS TIME...THE BEST FORECAST
IS A FRONTAL PASSAGE SOMETIME EARLY TO MID-MORNING A FEW HOURS AFTER
SUNRISE WHEREBY THERE COULD BE A BRIEF, BUT DECENT WARM-UP BEFORE
THE RUG IS PULLED UNDERNEATH US IN THE TEMPERATURE DEPARTMENT...AKIN
TO WHAT WE SAW A COUPLE OF TIMES IN APRIL WITH TREMENDOUS COLD AIR
ADVECTION ON THE ORDER OF 20 TO 30 DEGREE FALL IN TEMPERATURE OVER
THE SPAN OF JUST A FEW HOURS. THE OFFICIAL TEMPERATURE FORECAST WILL
TRY TO REFLECT A FAIRLY ROBUST DIURNAL FALL ON WEDNESDAY ACROSS MUCH
OF THE AREA.  RAIN SHOWERS WILL BE LIKELY ESPECIALLY ACROSS CENTRAL
AND SOUTH-CENTRAL KANSAS WITH A FEW EMBEDDED THUNDERSTORMS.

FRONTOGENESIS IN THE 800-700MB LAYER WILL BE STRENGTHENING LATE IN
THE DAY WEDNESDAY AND WEDNESDAY NIGHT ACROSS WESTERN KANSAS WITH THE
THERMODYNAMIC PROFILE RAPIDLY COOLING TO THE POINT THAT FROZEN
PRECIPITATION WILL ENTER THE PICTURE. THERE WILL LIKELY BE A NARROW
CORRIDOR OF SLEET DEVELOPING LATE WEDNESDAY ACROSS FAR WEST-CENTRAL
KANSAS BUT QUICKLY CHANGING TO WET SNOW AS SURFACE TEMPERATURES
CONTINUE TO FALL THROUGH THE LOWER 30S. AFTER WEDNESDAY
NIGHT...THERE IS CONSIDERABLE DIVERGENCE IN VARIOUS MODEL SOLUTIONS
REGARDING THE DEVELOPMENT OF THE MID LEVEL CYCLONE.  THE LATEST
ECMWF MODEL IS NOW BACK TO A MORE PROGRESSIVE SCENARIO RESULTING IN
THE LOW CLOSING OFF A BIT FARTHER EAST THAN YESTERDAY`S 12Z RUN. THE
LATEST 00Z VERSION OF THE CANADIAN GEM, ON THE OTHER HAND, HAS A
MUCH MORE FAVORABLE SCENARIO FOR LONGER-DURATION PRECIPITATION EVENT
AFFECTING CENTRAL AND SOUTH-CENTRAL KANSAS THURSDAY AND FRIDAY.
THIS STILL SEEMS LIKE AN OUTLIER SCENARIO SO POPS ON THURSDAY NIGHT
AND FRIDAY WILL BE IN THE SLIGHT CHANCE RANGE AND ONLY ACROSS THE
EASTERN COUNTIES (CENTRAL AND SOUTH-CENTRAL KANSAS).

A HISTORICAL NOTE OF REFERENCE REGARDING LATE-SEASON SNOW AT DODGE
CITY: THERE HAVE ONLY BEEN THREE OCCURRENCES IN THE HISTORY OF
WEATHER RECORDS OF MEASURABLE SNOW IN THE MONTH OF MAY AT DODGE CITY:

1) 0.9 INCHES ON 3 MAY 1978
2) 0.7 INCHES ON 6 MAY 1915
3) 0.3 INCHES ON 4 MAY 1979

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 700 AM CDT SUN APR 28 2013

QUIET AVIATION WEATHER IS EXPECTED TODAY AND TONIGHT IN A DRY
NORTHWEST FLOW REGIME. A WEAK LEE TROUGH AXIS WILL EXTEND FROM FAR
WESTERN KANSAS THROUGH CENTRAL NEBRASKA WITH WIND SPEEDS GENERALLY
FROM THE SOUTHWEST OR WEST-SOUTHWEST AT 7 TO 11 KNOTS. VFR
CONDITIONS ARE EXPECTED THROUGH MONDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  87  49  87  56 /   0   0  10  10
GCK  87  47  86  53 /   0   0   0  10
EHA  86  46  90  54 /   0   0   0   0
LBL  87  49  90  55 /   0   0   0   0
HYS  88  52  81  55 /   0  10  10  10
P28  85  54  88  58 /   0  10  10  10

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...UMSCHEID







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 1056 AM EDT SUN APR 28 2013

.UPDATE...

RAIN SHOWERS CONTINUE TO EDGE NORTHWARD INTO SOUTHEASTERN MICHIGAN
DURING THE LATE MORNING HOURS. HOWEVER THEY ARE ENCOUNTERING QUITE
A BIT OF LOW LEVEL DRY AIR AS EVIDENCED BY THE 12Z DTX RAOB
SOUNDING. THE LOCAL HI-RES MODELS ARE CAPTURING THIS QUITE WELL
AND KEEP MUCH OF THE ACTIVITY ALONG AND SOUTH OF M-59 THROUGH THE
EARLY AFTERNOON...THEN TRANSITIONING OFF TO THE EAST AS THE LOW
TRACKS EAST THROUGH OHIO. GIVEN THE ABUNDANT DRY AIR IN PLACE
ACROSS THE NORTH AND THE PERFORMANCE OF THE LOCAL 3KM HRRR MODEL
WILL TIGHTEN UP THE POPS ACROSS THE CWA...LOWERING AMOUNTS ACROSS
THE NORTH AND RAISING THEM ACROSS THE SOUTH.


&&

.AVIATION...ISSUED 717 AM EDT SUN APR 28 2013

//DISCUSSION...

INITIAL MOISTURE SURGE AND ELEVATED FORCING WILL SLIDE OVERHEAD OF
THE SOUTHERN TAF SITES DURING THE MORNING. A DRAMATIC LOWERING OF
CIGS TO MVFR IS EXPECTED WITH THIS FIRST PUSH OF MOISTURE. LIFR TO
VLIFR CEILINGS ARE THEN EXPECTED AFTER 19Z AS SECOND AREA OF
DEFORMATION FORCING DEVELOPS OVER EXTREME SECTIONS OF SOUTHEASTERN
MICHIGAN. MOISTURE QUALITY WILL BE HIGH WHICH BRINGS INCREASED
CONFIDENCE IN THE DEGRADATION OF AVIATION CONDITIONS FOR A LONG
DURATION TONIGHT.

FOR DTW...LINEAR EXTRAPOLATION OF LEAD MOISTURE SURGE IS SET FOR
NO LATER THAN 13Z THIS MORNING. A SECOND AREA OF FORCING WILL
ORGANIZE THIS AFTERNOON AND ALIGN SOUTHWEST TO NORTHEAST OVER THE
AREA. THE ADDITIONAL FORCING OVER A MOISTURE LADEN AIR MASS WILL
BRING A MEDIUM TO HIGH POTENTIAL FOR VLIFR CONDITIONS THROUGHOUT
TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BY 11Z-13Z.

* MEDIUM TO HIGH CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z
SUNDAY.

&&

.PREV DISCUSSION...ISSUED 356 AM EDT SUN APR 28 2013

SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA
BLOCK OVER THE EASTERN HALF OF THE COUNTRY.

MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

UPDATE.......KURIMSKI
AVIATION.....CB
SHORT TERM...CB
LONG TERM....BT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 741 AM EDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN APR 28 2013

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL FLOW FROM THE PACIFIC NW
TO THE NRN GREAT LAKES. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW
WAS MOVING THROUGH ERN SASK INTO MANITOBA WITH A TROUGH EXTENDING TO
THE CNTRL DAKOTAS. AHEAD OF THE TROUGH...SSW FLOW WAS INCREASING
OVER THE UPPER MS VALLEY AND NRN GREAT LAKES. WITH THE DRY AIRMASS
BELOW 700 MB...PER 00Z INL SOUNDING...WAA AHEAD OF THE TROUGH WAS
BRINGING MAINLY MID CLOUDS AND SOME VIRGA OR SPRINKLES INTO NRN MN.
ALTHOUGH DEWPOINTS HAD CLIMBED INTO THE MID 40S SRN AND CNTRL
MN...CIRCULATION AROUND THE LOW PRESSURE SYSTEM OVER SRN IL HAD
PREVENTED MORE ABUNDANT GULF MOISTURE FROM MOVING INTO THE REGION.

EXPECT THAT SUNSHINE AND MIXING TO 850-800 MB (850 MB TEMPS FROM 7C
TO 9C) WILL REULS IN MAX READINGS IN THE MID AND UPPER 60S EAST AND
LOWER 70S WEST. SRLY FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS
CLOSER TO 50.

AS THE SASKATCHEWAN LOW MOVES TO HUDSON BAY...IT WILL DRAG A COLD
FRONT INTO THE NRN GREAT LAKES TONIGHT. LOW LEVEL CONV NEAR THE
FRONT COMBINED WITH A WEAK SHORTWAVE MOVING OUT OF THE NRN PLAINS
WILL BE ENOUGH TO SUPPORT A BAND OF SHOWERS INTO UPPER MICHIGAN. THE
MODELS WERE IN GOOD AGREEMENT WITH THE FRONT AND PCPN BAND TRENDING
SLIGHTLY SLOWER. THE PCPN IS EXPECTED TO MOVE INTO THE WEST THIS
EVENING AND OVER THE CNTRL AND EAST OVERNIGHT. WITH ONLY WEAK
MID/UPPER LEVEL FORCING AND LIMITED MOISTURE INFLOW...OVERALL PCPN
AMOUNTS WILL BE LIGHT GENERALLY AOB 0.25 INCH...PER SREF PROB AND
CONSENSUS QPF. MDLS SUGGEST THAT ANY INSTABILITY TO SUPPORT TSRA WILL
REMAIN MAINLY TO THE S OF THE CWA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN APR 28 2013

BEST CONFIDENCE INTO WEDNESDAY...WITH MUCH REDUCED FORECAST
CONFIDENCE AFTER THAT. PUT PRIMARY EFFORTS/TIME INTO SHORTER TERM
GRIDS GIVEN FLOODING PROBLEMS THAT WILL BE MORE CONFINED TO SHORTER
TERM.

FOR MON...EXPECT A WEAK SFC TROUGH/COLD FRONT TO PUSH
THROUGH...KEEPING SFC TEMPS A LITTLE COOLER THAN YESTERDAY OR TODAY.
UP TO AROUND A QUARTER INCH OF QPF IS EXPECTED MON...BUT AT THE SAME
TIME MELTING OF THE SNOW PACK IS REDUCED BY EXTRA CLOUD COVER AND
COOLER TEMPS /ESPECIALLY NEAR LAKE SUPERIOR/...SO THESE TWO FACTORS
MAY CANCEL EACH OTHER OUT...STILL RESULTING IN A DECENT MELT
DAY...BUT THIS IS DIFFICULT TO DETERMINE.

TEMPORARY COOL DOWN MON COMES TO YET ANOTHER END WITH 60S AND 70
HIGH TEMPS OVER MUCH OF THE AREA TUE AS 850MB TEMPS INCREASE TO
AROUND 14C BY 18Z TUE. THESE WARMER TEMPS COME AHEAD OF ANOTHER
SYSTEM THAT WILL MOVE N OF LAKE SUPERIOR...WHICH BRINGS A COLD FRONT
ACROSS THE CWA LATE TUE INTO TUE NIGHT. MODELS ARE EVEN SHOWING
SOME CAPE ALONG AND AHEAD OF THE COLD FRONT...WHICH MAY RESULT IN
THUNDERSTORM ACTIVITY. THE HEAVIEST RAINFALL IS MAINLY FOCUSED OVER
THE ERN HALF OFF UPPER MI...AND WILL BE SOMETHING TO WATCH WITH
RESPECT TO CONTINUED FLOOD THREAT.

OTHER THAN THOSE SYSTEM...MODELS IN THE FARTHER EXTENDED SHOW LARGE
DISAGREEMENT IN THERMAL FIELDS...SO A WIDE VARIETY OF TEMPS ARE
POSSIBLE. ALTHOUGH MODELS DO SHOW GOOD GENERAL AGREEMENT...THE EXACT
PLACEMENT OF THE UPPER LOW THEY SHOW OVER THE CENTRAL CONUS BY FRI
IS ESSENTIAL FOR TEMPS/PRECIP. WILL JUST USE A CONSENSUS OF MODELS
FOR THIS PERIOD GIVEN THE UNCERTAINTY.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 739 AM EDT SUN APR 28 2013

EXPECT VFR CONDITIONS TO PREVAIL TODAY INTO THIS EVENING WITH THE
RELATIVELY DRY AIRMASS DOMINATING IN SW FLOW AROUND HIGH PRESSURE
OVER NEW ENGLAND. THE ONSET OF DAYTIME HEATING BY MID/LATE MORNING
WILL MIX OUT ANY HIGHER WINDS LEADING TO LLWS AND ALLOW GUSTY SW
WINDS TO REACH THE SFC. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 00Z
AHEAD OF AN INCOMING COLD FRONT...BUT LIMITED MOISTURE RETURN WILL
LIMIT PCPN INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN
VFR. BY LATE EVENING AND OVERNIGHT...EXPECT ENOUGH LOW LEVEL
MOISTENING FOR MVFR CONDITIONS TO DEVELOP.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN APR 28 2013

WINDS SHOULD STAY BELOW 25KTS THROUGH THE PERIOD WITH NO GALES IN
SIGHT. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&

.HYDROLOGY...
ISSUED AT 503 AM EDT SUN APR 28 2013

SAW GOOD MELTING YESTERDAY AFTERNOON WITH HIGH TEMPS IN THE 60S AND
70S AFTER THE SNOW PACK WARMED UP FROM SUB-FREEZING TEMPS THE NIGHT
BEFORE. SINCE TEMPS ARE WELL ABOVE FREEZING TONIGHT...AND HIGH TEMPS
TODAY WILL BE SIMILAR TO YESTERDAY BUT WITH SLIGHTLY HIGHER DEW
POINTS...WE SHOULD SEE EVEN BETTER MELTING FOR A LONGER PERIOD OF
TIME THAN YESTERDAY. PLACES WITH SNOWPACK REMAINING WILL SEE RAPID
AND EXTENSIVE MELTING TODAY...CAUSING RUNOFF INTO TONIGHT INTO AREA
STREAMS. RIVERS OF PARTICULAR CONCERN AFTER THE MELTING TODAY WILL
BE THE TRAP ROCK RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON
COUNTIES...AND THE PESHEKEE RIVER. RUNOFF MAY NOT PEAK UNTIL
TONIGHT/MONDAY...AND EVEN GET FORTIFIED BY ADDITIONAL MELTING AND
EVEN SOME RAIN ON MONDAY. RAINFALL AMOUNTS WILL GENERALLY BE AROUND
A QUARTER OF AN INCH...OR POSSIBLY MORE IN A FEW AREAS AND WILL
START LATE THIS EVENING INTO MONDAY. ANY RAIN WILL ONLY ADD TO
HYDROLOGIC CONCERNS...AND WILL HAVE TO PAY CLOSE ATTENTION TO PRECIP
AMOUNTS MONDAY. FURTHER CHANCES OF PRECIPITATION ARE EXPECTED AS
COLD FRONT WORKS THROUGH ON TUESDAY...WHEN THERE MAY BE
THUNDERSTORMS TOO. OTHERWISE...ADDITIONAL CHANCES OF PRECIPITATION
ARE POSSIBLE THE REST OF THE WEEK AS FRONT STAYS CLOSE BY TO THE
AREA.

MELTING SCENARIOS REMAIN THE BIGGEST CONFIDENCE REDUCERS AT THIS
POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE MELT
FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS WILL
LIKELY END UP QUITE A BIT HIGHER. ONCE PLACE WHERE THE MELT
CORRECTION FACTOR WAS INCREASED FOR FOR THE MEN RIVER FORECAST GROUP
/RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH RESULTED IN
MUCH INCREASED FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND
MODERATE FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR
REPUBLIC/WITCH LAKE. WFO SURVEY OF THE PESHEKEE RIVER REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS COULD CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES LATE TODAY INTO MONDAY. OF
COURSE...MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS WE ARE ALSO
LOOKING AT THREAT OF AREAL FLOOD PROBLEMS WITH SMALLER
CREEKS/STREAMS AND STANDING WATER ON ROADS. FOR FURTHER
DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE LATEST RIVER
WATCHES /FFAMQT/.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
HYDROLOGY...TITUS







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 717 AM EDT SUN APR 28 2013

.AVIATION...

//DISCUSSION...

INITIAL MOISTURE SURGE AND ELEVATED FORCING WILL SLIDE OVERHEAD OF
THE SOUTHERN TAF SITES DURING THE MORNING. A DRAMATIC LOWERING OF
CIGS TO MVFR IS EXPECTED WITH THIS FIRST PUSH OF MOISTURE. LIFR TO
VLIFR CEILINGS ARE THEN EXPECTED AFTER 19Z AS SECOND AREA OF
DEFORMATION FORCING DEVELOPS OVER EXTREME SECTIONS OF SOUTHEASTERN
MICHIGAN. MOISTURE QUALITY WILL BE HIGH WHICH BRINGS INCREASED
CONFIDENCE IN THE DEGRADATION OF AVIATION CONDITIONS FOR A LONG
DURATION TONIGHT.

FOR DTW...LINEAR EXTRAPOLATION OF LEAD MOISTURE SURGE IS SET FOR
NO LATER THAN 13Z THIS MORNING. A SECOND AREA OF FORCING WILL
ORGANIZE THIS AFTERNOON AND ALIGN SOUTHWEST TO NORTHEAST OVER THE
AREA. THE ADDITIONAL FORCING OVER A MOISTURE LADEN AIR MASS WILL
BRING A MEDIUM TO HIGH POTENTIAL FOR VLIFR CONDITIONS THROUGHOUT
TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BY 11Z-13Z.

* MEDIUM TO HIGH CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z
SUNDAY.

&&

.PREV DISCUSSION...ISSUED 356 AM EDT SUN APR 28 2013

SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA
BLOCK OVER THE EASTERN HALF OF THE COUNTRY.

MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....CB
SHORT TERM...CB
LONG TERM....BT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).










AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

 636 AM CDT SUN APR 28 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 315 AM CDT SUN APR 28 2013

AREAS OF DRIZZLE AND ISO-SCT RAIN SHOWERS SHOULD FINALLY END TODAY
AS A SLOW-MOVING LOW PRESSURE SYSTEM CONTINUES MOVING AWAY FROM THE
AREA. RAP BUFKIT PROFILES SHOW MIXING TO AROUND H9 THEREFORE HIGHS
IN THE LOW/MID 60S TO AROUND 70 LOOK REASONABLE CONSIDERING INITIAL
CLOUD COVER AND MOIST LOW LEVELS FM RECENT RAINFALL. TEMPERATURES
WILL BE WARMER IN CENTRAL MO THAN IN SWRN IL BECAUSE OF QUICKER
CLEARING IN THE WESTERN CWA.

KANOFSKY

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 28 2013

(TONIGHT - WEDNESDAY)

UPPER LEVEL RIDGE WILL BUILD OVER ERN NOAM EARLY IN THE PERIOD AND
THEN PROCEED TO DOMINATE THRU THE MIDDLE OF THE WEEK...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE HI PLAINS BY WEDNESDAY.
THIS SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.

THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY AND TUESDAY
MAX TEMPS...BUT IN SEVERAL LOCALES...WENT A COUPLE DEGS HIGHER TO
SUPPORT H900-850 TEMPS ALOFT DEPICTED BY THE MODELS AND ANTICIPATED
SUNSHINE.  LOOK FOR UPR 70S-LO 80S ON MONDAY WITH MID 80S TUESDAY
WITH A MORE SW WIND EXPECTED.  AN OUTSIDE CHANCE AT UPR 80S WILL
PRESENT ITSELF FOR PARTS OF STL METRO TUESDAY.  LOSS OF W COMPONENT
TO SFC WND ON WEDNESDAY AND SOME UNCERTAINTY ON WHERE FRONT WILL
BE...HAVE 80-85F FCSTD FOR MOST SPOTS.

TWO SMALL WINDOWS OF OPPORTUNITY FOR RAIN THIS PERIOD.  THE FIRST IS
ON MONDAY AFTERNOON-NIGHT.  MODELS ALL SHOW PRETTY STOUT INSTABILITY
AND 0-6KM BULK SHEAR OF 30-35KTS IN PLACE AHEAD OF WHAT SHOULD BE A
CDFNT EDGING INTO THE NWRN FA BY LATE MONDAY AFTERNOON BEFORE IT
STALLS AND WASHES OUT MONDAY NIGHT.  HOWEVER...SOME OF THESE LARGE
INSTABILITY VALUES ARE PREDICATED ON WHAT LOOKS TO BE A TOO
AGGRESSIVE LO LEVEL MOISTURE RETURN...AND A DEPENDENCE IN PART ON
SFC DWPTS REACHING INTO THE MID-UPR 60S.  HOWEVER...LO LEVEL MASS
FIELDS DO NOT SUPPORT A LO LEVEL MOISTURE RETURN OF THAT MAGNITUDE
WITH WEAK FLOW AND A WEAK BLOCKING RIDGE NEAR THE GULF OF MEXICO
UNTIL MONDAY AFTERNOON AND THEN IT SHOULD BE TOO SMALL A TIME PERIOD
TO GET THE RICH MOISTURE THAT FAR N.  SFC DWPTS INSTEAD EDGING NEAR
60F LOOK MORE LIKELY BUT THIS WILL STILL YIELD CINH VALUES AT OR
ABOVE 20 J/KG WHICH WILL PROBABLY BE ALL IT WILL NEED TO BLOCK MOST
CONVECTION WITH A WEAKENING SFC FRONT.  BUFR SOUNDINGS BASED ON OUR
LOCAL WRF DEPICT THIS WELL.  SO...IF SOMETHING CAN POP...IT SHOULD
SUPPORT DAY SHIFT YESTERDAY/S ASSERTION WITH DECENT CHANCE OF IT
GOING TO SEVERE...BUT OCCURRENCE OF ANY CONVECTION LOOKS TO BE
PRETTY LIMITED.  AFTER SUNSET MONDAY EVENING...CINH RAPIDLY
INCREASES WITH THE SFC FRONT STARTING TO WASH OUT...AND SO WINDOW
FOR CONVECTION WILL RAPIDLY CLOSE.  MADE MINIMAL CHANGES TO PREVIOUS
FCST WHICH ALREADY HAD MINIMAL CHC POPS LIMITED TO THE NW FA.

STILL SOME MODEL DIFFS ON TIMING OF THE SFC CDFNT FOR MID-LATE
WEEK...WITH THE GFS CONTINUING TO BE THE FASTEST INTO OUR AREA BY
WEDNESDAY AFTERNOON WITH THE ECMWF SOME 12HRS LATER INTO EARLY
THURSDAY MORNING.  BACKED OFF SOME ON POPS FOR WEDNESDAY WITH THE
ECMWF CONTINUING TO LEAD THE GFS TO WHAT HOPEFULLY WILL BE THE
VERIFYING SOLN...WHICH HAS STEADILY BEEN FAVORING A SLOWER FROPA.

(THURSDAY - SATURDAY)

LOOKING INCREASINGLY LIKE A COOL AND WET PERIOD.

THE LARGE DISCREPANCY ON WHEN AND WHERE TO FORM THE CUTOFF LO HAS
BEEN OVERCOME FOR THE MOST PART WITH THE GFS FOLLOWING THE ECMWF/S
LEAD FOR A MORE RAPID FORMATION...AND FURTHER W AS A RESULT.  STILL
SOME SMALL DIFFS AND EXPECT TO SEE SOME WOBBLING THE NEXT DAY OR
TWO.  UNFORTUNATELY...WHEN DEALING WITH CUTOFF UPPER LOWS...EVERY
WOBBLE WILL MAKE A PRETTY BIG DIFFERENCE ON RAIN CHCS AND TEMPS.

THE LATEST ITERATION FROM THE 00Z MODELS HAS A GENERAL CONSENSUS ON
THE UPPER LO FORMING AROUND THE INTERSECTION OF KS-MO-OK-AR ON
FRIDAY AND THEN GRADUALLY PULLING NWD THRU SATURDAY.  THOSE SLIGHT
DIFFS WILL MAKE A BIG DEAL AT THE SFC...WHERE ECMWF SHOWS A MORE
AGGRESSIVE CDFNT PUSH ON THURSDAY WITH NOTHING OF THE SORT FROM THE
GFS AND SO A LARGE TEMP FCST DIFF AS A RESULT ARISES...ESPECIALLY
THURSDAY NIGHT AND FRIDAY.  A BROAD CONSENSUS APPROACH PREFERRED FOR
TEMPS AS A RESULT.

ONE THING THAT LOOKS INCREASINGLY LIKELY IS THE RAIN CHCS...
ESPECIALLY IF THE UPPER LO SETS UP IN THE RIGHT SPOT ALMOST LIKE
MODELS DEPICT NOW...COULD BE SOME HEAVY RAINFALL POTENTIAL AS IT
TAPS INTO GULF OF MEXICO MOISTURE.

TES

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 622 AM CDT SUN APR 28 2013

FLIGHT CONDITIONS WILL IMPROVE FROM WEST TO EAST TODAY AS A SLOW-
MOVING LOW PRESSURE SYSTEM MOVES AWAY FROM THE AREA. CIGS SHOULD
RISE TO MVFR AT ALL TAF SITES BY EARLY AFTN WITH CONTINUED
IMPROVEMENT THEREAFTER. INITIALLY NWLY TO WLY WINDS WILL GRADUALLY
BACK THROUGH THE TAF PD AND BECOME SLY OVERNIGHT. THERE MAY BE
SOME LIGHT FOG DVLPMT TONIGHT DUE TO THE MOIST LOW LEVELS AND
CLRG SKIES HOWEVER THE MOST FAVORABLE AREAS FOR DENSE FOG WILL BE
EAST OF THE TAF SITES.

SPECIFICS FOR KSTL...FLIGHT CONDITIONS WILL IMPROVE TODAY AS A
SLOW-MOVING LOW PRESSURE SYSTEM MOVES AWAY FROM THE AREA. CIGS
SHOULD RISE TO MVFR BY LATE MORNING WITH CONTINUED IMPROVEMENT
THEREAFTER. INITIALLY NWLY TO WLY WINDS WILL GRADUALLY BACK
THROUGH THE TAF PD AND BECOME SLY OVERNIGHT.

KANOFSKY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION...UPDATED

NWS NORTH PLATTE NE

 623 AM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN APR 28 2013

SFC WINDS SHOULD INCREASE FROM THE WEST TOWARD MORNING AHEAD OF A
PACIFIC COLD FRONT FCST TO MOVE THROUGH DURING THE AFTN. THE RAP
SUPPORTS HIGHS IN THE MID 80S AHEAD OF THE FRONT ACROSS SWRN NEB AND
WINDS SHOULD INCREASE TO 15 TO 25 MPH AHEAD AND BEHIND THE FRONT.

FOR TONIGHT...A DISTURBANCE...CURRENTLY ACROSS THE NRN ROCKIES WILL
MOVE THROUGH NRN NEB. K INDICES SUPPORT TSTMS WEST OF HIGHWAY 83.
MOISTURE BELOW 700MB IS VERY LIMITED EAST OF 83 AND LAPSE RATES
NEARLY MOIST ADIABATIC.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN APR 28 2013

GUSTY SOUTHERLY WINDS AND CRITICALLY LOW RELATIVE HUMIDITY VALUES TO
BE EXPECTED ONCE AGAIN MONDAY AFTERNOON...WITH THE POTENTIAL OF
WIDESPREAD RED FLAG CONDITIONS.  FIRE HEADLINES MAY BE NECESSARY
ONCE AGAIN.  A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE
HIGH PLAINS ON MONDAY...ALLOWING FOR DOWNSLOPING SOUTHWESTERLY TO
WESTERLY WINDS AND HIGHS WELL INTO THE UPPER 70S...IF NOT LOW 80S.
WIND GUSTS WILL LIKELY EXCEED 25 MPH DURING PEAK HEATING AS THE
PRESSURE GRADIENT INCREASES AND STRONG TROPOSPHERIC MIXING
COMMENCES.  PREVIOUS FORECAST HAD HIGHS HANDLED WELL FOR
MONDAY...WITH ONLY MINOR UPWARD TWEAKS NEEDED ACROSS NORTHWESTERN
NEBRASKA...WHERE TEMPERATURES MAY SOAR IN ADVANCE OF A COLD FRONTAL
PASSAGE.  THE FRONT IS CURRENTLY PROGGED TO ARRIVE OVERNIGHT
MONDAY/EARLY TUESDAY...HOWEVER THERE IS LITTLE SUPPORT FOR
PRECIPITATION PRODUCTION INITIALLY.  PROXIMITY SOUNDINGS REVEAL VERY
LITTLE MOISTURE IN THE LOWER LEVELS...THUS WILL CONTINUE THE SILENT
14 POPS THROUGH THE OVERNIGHT.  TEMPERATURES HOWEVER WILL BE
NOTICEABLY COOLER ON TUESDAY...BUT THERE REMAINS DIFFERENCES BETWEEN
THE DETERMINISTIC SOLUTIONS IN THE AMOUNT OF COOLING...THE CONSENSUS
WOULD SUGGEST A 20-25F DECREASE IN HIGHS FROM MONDAY...WILL GO WITH
A RANGE OF HIGHS FROM THE MID 50S TO LOW 60S ACROSS THE CWA.  ALONG
WITH THE COOLER TEMPERATURES...PRECIPITATION CHANCES INCREASE
TUESDAY INTO WEDNESDAY AS A MIDLEVEL SHORTWAVE AND ASSOCIATED RRE OF
A 110 PLUS KT UPPER JET ADVANCES ON THE REGION.  THE HIGHEST QPF
WILL BE TIED TO THE MID-LEVEL FRONTOGENETIC FORCING WHICH SHOULD
BISECT THE CWA FROM SOUTHWEST TO NORTHEAST...WHICH MEANS CHANCES ARE
INCREASING FOR WELCOME WIDESPREAD QPF ACROSS THE HEART OF THE
SANDHILLS.  PTYPE MAY BECOME PROBLEMATIC EARLY ON WEDNESDAY...AS H85
TEMPERATURES ARE SHOWN TO FALL AS COLD AS -3C BY 12Z WEDNESDAY.
WILL INTRODUCE A RAIN/SNOW MIX ACROSS NORTHWEST NEBRASKA FROM
06Z-12Z...BUT NOT EXPECTING ANY ACCUMULATIONS AS GROUND TEMPERATURES
HAVE WARMED GREATLY.  GUIDANCE CAME IN COOLER ONCE AGAIN FOR
WEDNESDAY...AND GIVEN EXPECTED CLOUDY CONDITIONS WITH WEAK OR
NEUTRAL CAA...HIGHS IN THE LOWER 40S SHOULD BE THE NORM.  THE
REMAINDER OF THE EXTENDED FORECAST REMAINS INTERESTING AS A CLOSED
LOW DEVELOPS OVER CENTRAL KANSAS ON THURSDAY...AND THEREAFTER
MEANDERS AIMLESSLY THROUGH THE MISSOURI VALLEY/CORN BELT THROUGH THE
WEEKEND.  WITH BROAD CYCLONIC FLOW REMAINING ACROSS THE CENTRAL
CONUS...WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES INTO NEXT
WEEKEND WITH CONTINUED SLIGHT CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 621 AM CDT SUN APR 28 2013

VFR IS EXPECTED THROUGH 03Z THIS EVENING. THEREAFTER AND AREA OF
SHOWERS AND ISOLATED THUNDERSTORMS IS EXPECTED TO MOVE RAPIDLY
EAST ACROSS NRN NEB...GENERALLY ALONG HIGHWAY 20. CIGS SHOULD
REMAIN VFR.

&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT SUN APR 28 2013

RED FLAG CONDITIONS SHOULD DEVELOP AHEAD AND BEHIND THE COLD FRONT
FORECAST TO MOVE THROUGH SWRN NEB THIS AFTN. THE RAP AND HRRR ARE
LEADING THE WAY WITH DEW PTS IN THE 20S WHILE THE MOSGUIDE WIND
GUSTS ARE IN THE 20 TO 24 KT RANGE. THE DRIER MODEL DATA AND
STRONGER WIND GUSTS HAVE BEEN VERIFYING BETTER THAN THE WETTER
MODELS WHICH HAVE BEEN AS MUCH AS 10F TOO HIGH WITH DEW POINTS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 8 PM CDT /7
PM MDT/ THIS EVENING FOR NEZ204-206-209-210-219.

&&

$$

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 552 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 544 AM CDT SUN APR 28 2013

UPDATED THE FORECAST TO INCLUDE MENTION OF 1 MILE WITH THE FOG IN
THE FAR SOUTHEAST THIS MORNING AND TO INCLUDE SPRINKLES DOWN TO
THE STATE LINE LATE TONIGHT AS MORE MODELS ARE INDICATING SOME
POSSIBLE QPF...BUT AIR SHOULD BE SO DRY THAT SPRINKLE SHOULD
SUFFICE FARTHER TO THE SOUTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM CDT SUN APR 28 2013

BIGGEST CHALLENGE WILL BE DETERMINING EXTENT OF SOME POTENTIAL FOG
AND STRATUS IN THE SOUTHEASTERN CWA THIS MORNING...PLUS THE
POTENTIAL OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON/EVENING
NORTHEAST/EAST...AND ALSO A CHANCE OF RAIN LATE TONIGHT.
ALSO...DETERMINING THE HIGH TEMPERATURE TODAY COULD BE A BIT TRICKY.
ALSO...WE WILL BE APPROACHING ELEVATED FIRE DANGER FOR ROUGHLY OUR
NORTHWESTERN QUADRANT OF THE CWA.

THE HRRR WAS SPOT ON WITH FOG AND STRATUS YESTERDAY. WITH THE BEST
TRANSPORT OF MOISTURE SHIFTED SOUTHEAST...THE HRRR APPEARS TO BE ON
TRACK WITH DEVELOPING STRATUS AND FOG TO THE SOUTH. CURRENT
INTERPOLATIONS STILL CLIP US WITH STRATUS AND FOG IN OUR SOUTHEAST
EARLY THIS MORNING...MAINLY AFFECTING OUR 5 SOUTHEASTERN-MOST
COUNTIES. THIS IS EXTREMELY SHALLOW AND SHOULD NOT TAKE LONG TO BURN
OFF BY MID-MORNING.

THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY EAST...BUT WILL
STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY SOUTH ACROSS THE
CWA...COMING FROM THE NORTHERN PLAINS. WITH LOWERING DEWPOINTS FOR
MUCH OF THE CWA...ALONG WITH THE POTENTIAL FOR COMPRESSIONAL WARMING
AND VERY WARM 850 MB TEMPERATURES...I HAVE INCREASED HIGH
TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID 80S. JUDGING BY
RECENT MODEL PERFORMANCE...THIS IS THE DIRECTION TO TAKE.

ALSO...WE COULD GET AN ISOLATED THUNDERSTORM AS THE COLD FRONT MAKES
ITS WAY SOUTH...ESPECIALLY NORTHEAST/EAST WHERE INSTABILITY IS A
LITTLE HIGHER. BULK SHEAR WILL BE MARGINAL FOR SEVERE WEATHER...BUT
WE SHOULD HAVE JUST ENOUGH INSTABILITY TO THROW IN A MENTION OF
PERHAPS SOME HAIL UP TO THE SIZE OF NICKELS ALONG AND EAST OF
HIGHWAY 14.

A MID-LEVEL WAVE COULD GIVE US POST-FRONTAL SHOWER ACTIVITY IN THE
NORTH. THERE DOES NOT APPEAR TO BE ENOUGH MID-LEVEL INSTABILITY TO
SUPPORT THUNDER. ENSEMBLES SUGGEST RAIN POTENTIALLY FARTHER
SOUTH...BUT THIS DOES NOT APPEAR TO BE A POPULAR SOLUTION ON HIGH
RESOLUTION SHORT RANGE MODELS...SO I WILL CONTINUE TO FOCUS CHANCES
IN OUR NORTHERN CWA. THE 06Z RUN DOES INDICATE POSSIBLE RAIN AS FAR
SOUTH AS THE STATE BORDER...POSSIBLY HELPED BY A WEAK AREA OF LEFT
INDUCED BY THE RIGHT REAR QUADRANT OF AN EXTREMELY MODELS JET
STREAK.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 515 AM CDT SUN APR 28 2013

ALTHOUGH UNCERTAINTY REMAINS HIGH IN THE DETAILS...THE GENERAL
THEME OF THIS 6-DAY PERIOD HAS CHANGED LITTLE OVER THE PAST 24
HOURS...WITH AT LEAST ONE MORE DAY OF ABOVE NORMAL WARMTH ON
MONDAY FOLLOWED BY THE PASSAGE OF A STRONG COLD FRONT
TUESDAY/TUESDAY NIGHT...WITH WELL BELOW NORMAL TEMPS THEN
PREVAILING THROUGH THE REMAINDER OF THE WEEK...ALTHOUGH THE JURY
IS STILL OUT ON JUST HOW COLD. PRECIP-WISE...ALL OR PART OF THE
CWA NOW HAS POPS MENTIONED FOR 9 CONSECUTIVE FORECAST PERIODS FROM
TUESDAY AFTERNOON THROUGH SATURDAY. THIS IS NOT AN IDEAL SITUATION
FOR PUBLIC FORECAST PRODUCTS AS IT OFTEN CREATES THE IMPRESSION
THAT IT WILL BE WETTER THAN IT ACTUALLY ENDS UP BEING...BUT GIVEN
MODEL VARIABILITY ITS JUST THE WAY IT IS FOR NOW. IN ALL REALITY
THOUGH...SOME OF THESE POPS MAY EVENTUALLY BE REDUCED/CUT IN
LATER FORECASTS...AS MODELS CONTINUE TO VARY CONSIDERABLY FROM
RUN-TO-RUN WITH THE PLACEMENT/LIKELIHOOD OF PRECIP POTENTIAL
BEYOND WEDNESDAY NIGHT. AT THIS POINT...BY FAR THE BEST CHANCES
FOR WIDESPREAD RAIN...AND POSSIBLY EVEN SOME SNOW MIXED
IN...OCCURS BETWEEN TUESDAY NIGHT AND WEDNESDAY NIGHT...WITH
UNCERTAINTY RAMPING UP THEREAFTER. THERE ALSO REMAINS A RISK FOR
STRONG/SEVERE STORMS TUESDAY AFTERNOON BUT LIKELY MORE SO TUESDAY
EVENING. ON TO THE DETAILS...

MONDAY/MONDAY NIGHT...CONFIDENCE REMAINS REASONABLY HIGH IN A DRY
24 HOURS. VARIOUS 00Z MODELS SUCH AS THE NAM/GFS/ECMWF AGREE THAT
THE LARGE SCALE PICTURE ALOFT FEATURES QUASI-ZONAL FLOW...AS ONE
LOW AMPLITUDE SHORTWAVE TROUGH DEPARTS EAST OF THE CWA DURING THE
DAY...WHILE UPSTREAM AN UPPER JET STREAK STARTS CARVING OUT
LARGER...BROADER TROUGH OVER THE NORTHERN ROCKIES/NORTHERN PLAINS.
RIGHT AWAY IN THE MORNING...IT COULD BE A CLOSE CALL WHETHER OR
NOT A BRIEF PERIOD OF LINGERING SPRINKLES/LIGHT SHOWERS FROM THE
SUNDAY NIGHT PERIOD COULD STILL BE SKIRTING EASTERN ZONES...BUT
VARIOUS MODELS INCLUDING REFLECTIVITY PROG FROM 4 KM WRF-NMM SHOVE
THIS ACTIVITY EAST BY 12Z SO WILL KEEP THE OFFICIAL MORNING PERIOD
PRECIP-FREE. LATER IN THE DAY...MODELS SUCH AS THE NAM BUILD A
HEALTHY AREA OF 2000+ J/KG SURFACE-BASED CAPE IN SOUTHEAST
COUNTIES...BUT NOT THINKING MUCH OF A THUNDERSTORM THREAT DUE TO
LIMITED FORCING AND PLENTY OF CAPPING EVIDENT IN FORECAST
SOUNDINGS. FURTHERMORE...THE MAGNITUDE OF MODELED INSTABILITY IS
LIKELY A BIT OVERDONE DUE TO OVERDONE SURFACE DEW POINT VALUES.
ASSUMING NO CONVECTION FIRES...IT SHOULD BE A QUIET AND MILD DAY
AS SURFACE BREEZES GENERALLY 10-15 MPH TRANSITION FROM EASTERLY TO
SOUTHERLY. GIVEN SLIGHTLY COOLER 850MB TEMPS AND LESS FAVORABLE
MIXING THAN TODAY...ANTICIPATE A SLIGHTLY COOLER MONDAY...AND MADE
LITTLE CHANGE TO HIGHS RANGING FROM MID 70S FAR NORTH TO LOW 80S
SOUTHWEST. LATE MONDAY NIGHT...THERE IS DECENT MODEL CONSENSUS
THAT THE LEADING EDGES OF THE COLD FRONT RACES SOUTHEAST INTO THE
NORTHWESTERN CWA BEFORE SUNRISE...ALTHOUGH THE NAM/GFS SEEM TO BE
FASTER WITH THIS FRONTAL INVASION THAN THE ECMWF. THE LATEST 06Z
NAM IS NOW SUGGESTING A NARROW LINE OF SHOWS/STORMS COULD BRUSH
FAR NORTHERN ZONES LATE MONDAY NIGHT JUST BEHIND THIS FRONT...BUT
WITH LIMITED SUPPORT FROM OTHER SOLUTIONS WILL OMIT ANY PRECIP
MENTION FOR NOW ALTHOUGH IT BEARS WATCHING. MADE LITTLE CHANGE TO
LOW TEMPS WITH LOW-MID 50S MOST AREAS EXCEPT UPPER 40S FAR
NORTHWEST.

TUESDAY/TUESDAY NIGHT...THINGS BECOME MORE ACTIVE ITS JUST A
MATTER OF HOW MUCH SO. ALOFT...THE NORTHERN ROCKIES/NORTHERN
PLAINS TROUGH AMPLIFIES IN A POSITIVELY TILTED FASHION...WHILE IN
THE LOW LEVELS THE FAIRLY STRONG COLD FRONT CONTINUES TO SWEEP
SOUTHWARD ACROSS THE CWA...AND HAVE INCREASED NORTH-NORTHEAST
SUSTAINED WIND SPEEDS TO AROUND 20 MPH IN ITS WAKE. FOR SOME
REASON...THE 00Z ECMWF IS STARTING TO LOOK LIKE MORE OF AN OUTLIER
WITH ITS SLOWER COLD FRONTAL PASSAGE...ALTHOUGH THE NAM MAY BE A
BIT TOO AGGRESSIVE. THIS UNCERTAINTY IN THE MAGNITUDE OF DAYTIME COLD
AIR ADVECTION RESULTS IN QUITE A BIT OF UNCERTAINTY IN HIGH
TEMPS...AND COULD EASILY SEE CURRENT FORECAST BEING 5-10 DEGREES
OFF FROM CURRENTLY ADVERTISED VALUES...WHICH ARE A MULTI-MODEL
BLEND. LEANING TOWARD THE FASTER COLD AIR INVASION...NUDGED DOWN
HIGHS ROUGHLY 3-4 DEGREES FROM PREVIOUS...AIMING FOR A DECENT
GRADIENT FROM NEAR 60 FAR NORTH TO UPPER 70S FAR SOUTHEAST. AS FOR
CONVECTIVE POTENTIAL...HELD OFF ANY MENTION OF DAYTIME STORMS
UNTIL POST-21Z...AND KEPT THE EXACT SAME AREA FROM PREVIOUS
FORECAST MAINLY SOUTH OF A YORK-ALMA LINE IN CLOSEST PROXIMITY TO
THE SURFACE FRONT. HOWEVER...IF THE FASTER FRONTAL SOLUTIONS SUCH
AS THE NAM VERIFY THEN THE PRIMARY LOW LEVEL INSTABILITY AXIS AND
RESULTANT RISK FOR POTENTIALLY NEAR-SURFACE BASED STORMS WOULD
ACTUALLY FOCUS SOUTHEAST OF THE CWA. THIS COULD BE A CLOSE CALL.
OF GREATER CONFIDENCE AT THIS POINT IS AN INCREASE IN COVERAGE OF
EVENING/OVERNIGHT PRECIPITATION WELL-BEHIND THE SURFACE
FRONT...AS LARGE SCALE MID LEVEL CONVERGENCE MOVES IN FROM THE
NORTHWEST. EVEN IF THE CWA IS SPARED SURFACE-BASED STORMS...IT
STILL LOOKS LIKE A FAIRLY AGGRESSIVE DEVELOPMENT OF AT LEAST
SLIGHTLY ELEVATED STORMS WILL FLARE UP NEAR OR SHORTLY AFTER
SUNSET IN RESPONSE TO INCREASING MOISTURE TRANSPORT/WIND
CONVERGENCE INTO THE MID-LEVEL FRONTAL ZONE EVIDENT AT 700MB.
WHILE HAIL WOULD LIKELY BE THE MAIN THREAT WITH THESE STORMS...THE
MAGNITUDE OF THE SEVERE RISK WILL ULTIMATELY DEPEND ON THE AMOUNT
OF ELEVATED INSTABILITY...WITH THE LATEST NAM ONLY ADVERTISING
LESS THAN 500 J/KG IN THE 850-700MB LAYER...BUT THE GFS STILL
CLOSER TO 1000 J/KG. DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT AT LEAST MARGINAL SEVERE...AVERAGING AROUND 50KT.
CERTAINLY THE MAIN SEVERE THREAT AREA SHOULD FOCUS ACROSS ROUGHLY
THE SOUTHEAST 1/3 OF THE CWA...AND WILL BE MAKING LITTLE CHANGE
TO HAZARDOUS WEATHER OUTLOOK WORDING. EVEN NORTH OF THE MAIN
THUNDERSTORM AREA...WIDESPREAD RAIN SHOWERS SHOULD BREAK OUT
DURING THE NIGHT...AND POPS WERE RAISED TO 70 PERCENT ACROSS
NEARLY THE ENTIRE CWA. ALTHOUGH THE NAM/GFS THERMAL PROFILES
SUGGEST THAT SOME WET SNOW COULD MIX IN WITH RAIN MAINLY IN FAR
NORTHWEST ZONES LATE IN THE NIGHT...WILL KEEP PRECIP TYPE AS ALL
RAIN FOR NOW...DESPITE LOW TEMPS AIMED FROM MID 30S NORTHWEST TO
MID 40S SOUTHEAST.

WEDNESDAY/WEDNESDAY NIGHT...BY THIS TIME THE CWA IS FIRMLY IN THE
GRIPS OF THE COLDER REGIME. THE 00Z ECMWF/GFS RUNS ARE IN BETTER
AGREEMENT THAN 24 HOURS AGO ON THE SYNOPTIC SCENE...AS THEY BOTH
SLOWLY SHIFT THE INCREASINGLY-AMPLIFIED BUT STILL POSITIVELY
TILTED MID-UPPER TROUGH FROM THE NORTHERN PLAINS/CENTRAL ROCKIES
INTO THE CENTRAL PLAINS...WHILE AT THE SURFACE BREEZY NORTH WINDS
PERSIST. THE DOWNWARD NUDGING TO DAYTIME HIGHS CONTINUES...AND NOW
HAVE ALL BUT THE FAR SOUTHEAST CWA ONLY TOPPING OUT SOMEWHERE IN
THE 40S...WITH FURTHER DOWNWARD NUDGES STILL VERY MUCH POSSIBLE
GIVEN THAT PRECIP IS STILL EXPECTED TO BE FAIRLY WIDESPREAD DURING
THE DAY AS THE SOUTHWEST-NORTHEAST ORIENTED MID LEVEL
FRONTOGENETIC ZONE CENTERS OVERHEAD. AT LEAST FOR ONE MORE
FORECAST CYCLE...HAVE LEFT DAYTIME PRECIP TYPE AS RAIN-
ONLY...ALTHOUGH ITS BECOMING INCREASINGLY LIKELY THAT AT LEAST A
MIX WITH SNOW MAY SOON NEED INSERTED ESPECIALLY IN NORTHWEST
AREAS...ESPECIALLY IF HIGH TEMPS CONTINUE A DOWNWARD TREND. BY
THIS TIME INSTABILITY SHOULD BE MINIMAL EVEN IN SOUTHEAST COUNTIES
AND WILL LEAVE OUT THUNDER. POPS WERE UPPED TO 60 PERCENT
LIKELIES IN MOST AREAS...AS THIS IS SHAPING UP TO BE A RATHER WET
AND VERY RAW FIRST DAY OF MAY. WEDNESDAY NIGHT...KEPT AT LEAST
30-50 POPS GOING ALL AREAS FOR A RAIN/SNOW MIX WITH A LIGHT SNOW
ACCUMULATION NOT OUT OF THE QUESTION...ALTHOUGH BOTH THE ECMWF/GFS
ARE IN DECENT AGREEMENT PUSHING PRECIP OUT FROM NORTHWEST-
SOUTHEAST AS THE NIGHT WEARS ON. KEPT LOW TEMPS BARELY ABOVE
FREEZING ACROSS MOST OF THE CWA WEDNESDAY NIGHT...BUT ANY FROST
THREAT WOULD SEEM VERY MINIMAL GIVEN ONGOING PRECIP AND CONTINUED
MODEST NORTH BREEZES.

TURNING TO THE THURSDAY THROUGH SATURDAY TIME FRAME IN LESS
DETAILED FASHION...THE ONE BIT OF GOOD NEWS IS THAT THE ECWMF/GFS
SOLUTIONS ARE NOW IN INCREDIBLY GOOD AGREEMENT...AT LEAST FOR NOW...ON
THE EVOLUTION OF THE TIGHTLY WOUND CLOSED MID LEVEL LOW THAT IS
FORECAST TO DEVELOP ACROSS THE CENTRAL CONUS AS THE PARENT LARGE
SCALE TROUGH AXIS RUNS INTO A SOLID WALL IN THE FORM OF A STOUT
OMEGA BLOCK RIDGE OVER THE EASTERN CONUS. THE BEGINNING STAGES OF
THIS CLOSING OFF PROCESS TAKES PLACE THURS/THURS NIGHT...GENERALLY
CENTERED SOMEWHERE BETWEEN NORTHERN OK AND EASTERN KS. THIS IS
FARTHER EAST IN THE ECMWF FROM PREVIOUS RUNS...WITH THIS MODEL NOW
ACTUALLY KEEPING MOST OF THE CWA DRY FROM THURS AFTERNOON THROUGH
FRIDAY EVENING. HOWEVER...GIVEN PLENTY OF UNCERTAINTY IN THIS
LATEST SOLUTION WILL KEEP LOW POPS FOR EITHER CHILLY RAIN OR A
RAIN/SNOW MIX GOING ACROSS PART OR ALL OF THE CWA THIS ENTIRE TIME
FOR NOW. BY FRIDAY NIGHT INTO SATURDAY...BOTH OF THESE MODELS LIFT
THE CLOSED LOW BACK NORTH FROM MO TOWARD IA...WITH EVEN THE ECMWF
WRAPPING PRECIP CHANCES WESTWARD BACK INTO AT LEAST THE EASTERN
CWA BY THIS TIME. DAILY/NIGHTLY TEMPERATURES WILL DEPEND SO MUCH
ON WHETHER OR NOT WIDESPREAD CLOUDS AND/OR PRECIP ARE
PRESENT...BUT AT LEAST FOR NOW CONTINUED THE DOWNWARD TREND FOR
HIGH TEMPS THURS-SAT...WITH MAINLY UPPER 40S NOW THURS AND LOW 50S
FRI-SAT. OVERNIGHT LOWS BOTH FRI AND SAT MORNING ARE FORECAST
RIGHT AROUND OR JUST BELOW THE 32 DEGREE FREEZING MARK...BUT
HOLDING ABOVE THE 28 DEGREE HARD FREEZE THRESHOLD. AT THE VERY
LEAST...MAY EVENTUALLY HAVE TO INSERT A FROST MENTION FOR FRIDAY
MORNING...BUT CONFIDENCE IS TOO LOW AT THIS TIME RANGE...AND THERE
ARE ALREADY PLENTY MORE IMMEDIATE ISSUES TO DEAL WITH IN THE
SHORTER TERM...SO WILL NOT EXPLICITLY INTRODUCE FROST/FREEZE
CONCERNS IN THE FORECAST PRODUCTS JUST YET. HOWEVER...ITS CERTAINLY
NOT OUT OF THE QUESTION THAT AT LEAST ONE NIGHT MID-LATE NEXT
WEEK COULD REQUIRE A FROST/FREEZE HEADLINE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 544 AM CDT SUN APR 28 2013

ONLY MID-HIGH LEVEL SKY COVER FOR THIS FORECAST. AS THE PRESSURE
GRADIENT INCREASES BY THIS AFTERNOON...A BIT OF A GUST IS POSSIBLE
OUT OF THE WEST AS A DRY LINE MOVES EAST INTO THE AREA AND A COLD
FRONT APPROACHES FROM THE NORTH. SOME THUNDERSTORMS ARE POSSIBLE
TO THE NORTHEAST...BUT SHOULD REMAIN OUT OF THE AREA. COULD SEE
ISOLATED SPRINKLES LATE TONIGHT...BUT CHANCES ARE SO LOW THAT THIS
WAS LEFT OUT OF THE FORECAST AND WOULD BE OF LITTLE SIGNIFICANCE
ANYWAY.

&&

.FIRE WEATHER...
ISSUED AT 515 AM CDT SUN APR 28 2013

FOR TODAY...THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY
EAST...BUT WILL STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY
SOUTH ACROSS THE CWA...COMING FROM THE NORTHERN PLAINS. WITH
LOWERING DEWPOINTS FOR MUCH OF THE CWA...ALONG WITH THE POTENTIAL
FOR COMPRESSIONAL WARMING AND VERY WARM 850 MB TEMPERATURES...I
HAVE INCREASED HIGH TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID
80S. RELATIVE HUMIDITY SHOULD BE SOLIDLY DRY FOR ITS PART TOWARD
CRITICAL FIRE WEATHER...BUT THE WINDS WILL BE LACKING A BIT...WITH
THE MOST POTENTIAL FOR FIRE ISSUES COMING FROM THE GUSTS AS THE
COLD FRONT MAKES ITS WAY TOWARD THE NORTHWESTERN CWA BY MID-LATE
AFTERNOON.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

UPDATE...HEINLEIN
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...HEINLEIN





AREA FORECAST DISCUSSION

NWS HASTINGS NE

 519 AM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM CDT SUN APR 28 2013

BIGGEST CHALLENGE WILL BE DETERMINING EXTENT OF SOME POTENTIAL FOG
AND STRATUS IN THE SOUTHEASTERN CWA THIS MORNING...PLUS THE
POTENTIAL OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON/EVENING
NORTHEAST/EAST...AND ALSO A CHANCE OF RAIN LATE TONIGHT.
ALSO...DETERMINING THE HIGH TEMPERATURE TODAY COULD BE A BIT TRICKY.
ALSO...WE WILL BE APPROACHING ELEVATED FIRE DANGER FOR ROUGHLY OUR
NORTHWESTERN QUADRANT OF THE CWA.

THE HRRR WAS SPOT ON WITH FOG AND STRATUS YESTERDAY. WITH THE BEST
TRANSPORT OF MOISTURE SHIFTED SOUTHEAST...THE HRRR APPEARS TO BE ON
TRACK WITH DEVELOPING STRATUS AND FOG TO THE SOUTH. CURRENT
INTERPOLATIONS STILL CLIP US WITH STRATUS AND FOG IN OUR SOUTHEAST
EARLY THIS MORNING...MAINLY AFFECTING OUR 5 SOUTHEASTERN-MOST
COUNTIES. THIS IS EXTREMELY SHALLOW AND SHOULD NOT TAKE LONG TO BURN
OFF BY MID-MORNING.

THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY EAST...BUT WILL
STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY SOUTH ACROSS THE
CWA...COMING FROM THE NORTHERN PLAINS. WITH LOWERING DEWPOINTS FOR
MUCH OF THE CWA...ALONG WITH THE POTENTIAL FOR COMPRESSIONAL WARMING
AND VERY WARM 850 MB TEMPERATURES...I HAVE INCREASED HIGH
TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID 80S. JUDGING BY
RECENT MODEL PERFORMANCE...THIS IS THE DIRECTION TO TAKE.

ALSO...WE COULD GET AN ISOLATED THUNDERSTORM AS THE COLD FRONT MAKES
ITS WAY SOUTH...ESPECIALLY NORTHEAST/EAST WHERE INSTABILITY IS A
LITTLE HIGHER. BULK SHEAR WILL BE MARGINAL FOR SEVERE WEATHER...BUT
WE SHOULD HAVE JUST ENOUGH INSTABILITY TO THROW IN A MENTION OF
PERHAPS SOME HAIL UP TO THE SIZE OF NICKELS ALONG AND EAST OF
HIGHWAY 14.

A MID-LEVEL WAVE COULD GIVE US POST-FRONTAL SHOWER ACTIVITY IN THE
NORTH. THERE DOES NOT APPEAR TO BE ENOUGH MID-LEVEL INSTABILITY TO
SUPPORT THUNDER. ENSEMBLES SUGGEST RAIN POTENTIALLY FARTHER
SOUTH...BUT THIS DOES NOT APPEAR TO BE A POPULAR SOLUTION ON HIGH
RESOLUTION SHORT RANGE MODELS...SO I WILL CONTINUE TO FOCUS CHANCES
IN OUR NORTHERN CWA. THE 06Z RUN DOES INDICATE POSSIBLE RAIN AS FAR
SOUTH AS THE STATE BORDER...POSSIBLY HELPED BY A WEAK AREA OF LEFT
INDUCED BY THE RIGHT REAR QUADRANT OF AN EXTREMELY MODELS JET
STREAK.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 515 AM CDT SUN APR 28 2013

ALTHOUGH UNCERTAINTY REMAINS HIGH IN THE DETAILS...THE GENERAL
THEME OF THIS 6-DAY PERIOD HAS CHANGED LITTLE OVER THE PAST 24
HOURS...WITH AT LEAST ONE MORE DAY OF ABOVE NORMAL WARMTH ON
MONDAY FOLLOWED BY THE PASSAGE OF A STRONG COLD FRONT
TUESDAY/TUESDAY NIGHT...WITH WELL BELOW NORMAL TEMPS THEN
PREVAILING THROUGH THE REMAINDER OF THE WEEK...ALTHOUGH THE JURY
IS STILL OUT ON JUST HOW COLD. PRECIP-WISE...ALL OR PART OF THE
CWA NOW HAS POPS MENTIONED FOR 9 CONSECUTIVE FORECAST PERIODS FROM
TUESDAY AFTERNOON THROUGH SATURDAY. THIS IS NOT AN IDEAL SITUATION
FOR PUBLIC FORECAST PRODUCTS AS IT OFTEN CREATES THE IMPRESSION
THAT IT WILL BE WETTER THAN IT ACTUALLY ENDS UP BEING...BUT GIVEN
MODEL VARIABILITY ITS JUST THE WAY IT IS FOR NOW. IN ALL REALITY
THOUGH...SOME OF THESE POPS MAY EVENTUALLY BE REDUCED/CUT IN
LATER FORECASTS...AS MODELS CONTINUE TO VARY CONSIDERABLY FROM
RUN-TO-RUN WITH THE PLACEMENT/LIKELIHOOD OF PRECIP POTENTIAL
BEYOND WEDNESDAY NIGHT. AT THIS POINT...BY FAR THE BEST CHANCES
FOR WIDESPREAD RAIN...AND POSSIBLY EVEN SOME SNOW MIXED
IN...OCCURS BETWEEN TUESDAY NIGHT AND WEDNESDAY NIGHT...WITH
UNCERTAINTY RAMPING UP THEREAFTER. THERE ALSO REMAINS A RISK FOR
STRONG/SEVERE STORMS TUESDAY AFTERNOON BUT LIKELY MORE SO TUESDAY
EVENING. ON TO THE DETAILS...

MONDAY/MONDAY NIGHT...CONFIDENCE REMAINS REASONABLY HIGH IN A DRY
24 HOURS. VARIOUS 00Z MODELS SUCH AS THE NAM/GFS/ECMWF AGREE THAT
THE LARGE SCALE PICTURE ALOFT FEATURES QUASI-ZONAL FLOW...AS ONE
LOW AMPLITUDE SHORTWAVE TROUGH DEPARTS EAST OF THE CWA DURING THE
DAY...WHILE UPSTREAM AN UPPER JET STREAK STARTS CARVING OUT
LARGER...BROADER TROUGH OVER THE NORTHERN ROCKIES/NORTHERN PLAINS.
RIGHT AWAY IN THE MORNING...IT COULD BE A CLOSE CALL WHETHER OR
NOT A BRIEF PERIOD OF LINGERING SPRINKLES/LIGHT SHOWERS FROM THE
SUNDAY NIGHT PERIOD COULD STILL BE SKIRTING EASTERN ZONES...BUT
VARIOUS MODELS INCLUDING REFLECTIVITY PROG FROM 4 KM WRF-NMM SHOVE
THIS ACTIVITY EAST BY 12Z SO WILL KEEP THE OFFICIAL MORNING PERIOD
PRECIP-FREE. LATER IN THE DAY...MODELS SUCH AS THE NAM BUILD A
HEALTHY AREA OF 2000+ J/KG SURFACE-BASED CAPE IN SOUTHEAST
COUNTIES...BUT NOT THINKING MUCH OF A THUNDERSTORM THREAT DUE TO
LIMITED FORCING AND PLENTY OF CAPPING EVIDENT IN FORECAST
SOUNDINGS. FURTHERMORE...THE MAGNITUDE OF MODELED INSTABILITY IS
LIKELY A BIT OVERDONE DUE TO OVERDONE SURFACE DEW POINT VALUES.
ASSUMING NO CONVECTION FIRES...IT SHOULD BE A QUIET AND MILD DAY
AS SURFACE BREEZES GENERALLY 10-15 MPH TRANSITION FROM EASTERLY TO
SOUTHERLY. GIVEN SLIGHTLY COOLER 850MB TEMPS AND LESS FAVORABLE
MIXING THAN TODAY...ANTICIPATE A SLIGHTLY COOLER MONDAY...AND MADE
LITTLE CHANGE TO HIGHS RANGING FROM MID 70S FAR NORTH TO LOW 80S
SOUTHWEST. LATE MONDAY NIGHT...THERE IS DECENT MODEL CONSENSUS
THAT THE LEADING EDGES OF THE COLD FRONT RACES SOUTHEAST INTO THE
NORTHWESTERN CWA BEFORE SUNRISE...ALTHOUGH THE NAM/GFS SEEM TO BE
FASTER WITH THIS FRONTAL INVASION THAN THE ECMWF. THE LATEST 06Z
NAM IS NOW SUGGESTING A NARROW LINE OF SHOWS/STORMS COULD BRUSH
FAR NORTHERN ZONES LATE MONDAY NIGHT JUST BEHIND THIS FRONT...BUT
WITH LIMITED SUPPORT FROM OTHER SOLUTIONS WILL OMIT ANY PRECIP
MENTION FOR NOW ALTHOUGH IT BEARS WATCHING. MADE LITTLE CHANGE TO
LOW TEMPS WITH LOW-MID 50S MOST AREAS EXCEPT UPPER 40S FAR
NORTHWEST.

TUESDAY/TUESDAY NIGHT...THINGS BECOME MORE ACTIVE ITS JUST A
MATTER OF HOW MUCH SO. ALOFT...THE NORTHERN ROCKIES/NORTHERN
PLAINS TROUGH AMPLIFIES IN A POSITIVELY TILTED FASHION...WHILE IN
THE LOW LEVELS THE FAIRLY STRONG COLD FRONT CONTINUES TO SWEEP
SOUTHWARD ACROSS THE CWA...AND HAVE INCREASED NORTH-NORTHEAST
SUSTAINED WIND SPEEDS TO AROUND 20 MPH IN ITS WAKE. FOR SOME
REASON...THE 00Z ECMWF IS STARTING TO LOOK LIKE MORE OF AN OUTLIER
WITH ITS SLOWER COLD FRONTAL PASSAGE...ALTHOUGH THE NAM MAY BE A
BIT TOO AGGRESSIVE. THIS UNCERTAINTY IN THE MAGNITUDE OF DAYTIME COLD
AIR ADVECTION RESULTS IN QUITE A BIT OF UNCERTAINTY IN HIGH
TEMPS...AND COULD EASILY SEE CURRENT FORECAST BEING 5-10 DEGREES
OFF FROM CURRENTLY ADVERTISED VALUES...WHICH ARE A MULTI-MODEL
BLEND. LEANING TOWARD THE FASTER COLD AIR INVASION...NUDGED DOWN
HIGHS ROUGHLY 3-4 DEGREES FROM PREVIOUS...AIMING FOR A DECENT
GRADIENT FROM NEAR 60 FAR NORTH TO UPPER 70S FAR SOUTHEAST. AS FOR
CONVECTIVE POTENTIAL...HELD OFF ANY MENTION OF DAYTIME STORMS
UNTIL POST-21Z...AND KEPT THE EXACT SAME AREA FROM PREVIOUS
FORECAST MAINLY SOUTH OF A YORK-ALMA LINE IN CLOSEST PROXIMITY TO
THE SURFACE FRONT. HOWEVER...IF THE FASTER FRONTAL SOLUTIONS SUCH
AS THE NAM VERIFY THEN THE PRIMARY LOW LEVEL INSTABILITY AXIS AND
RESULTANT RISK FOR POTENTIALLY NEAR-SURFACE BASED STORMS WOULD
ACTUALLY FOCUS SOUTHEAST OF THE CWA. THIS COULD BE A CLOSE CALL.
OF GREATER CONFIDENCE AT THIS POINT IS AN INCREASE IN COVERAGE OF
EVENING/OVERNIGHT PRECIPITATION WELL-BEHIND THE SURFACE
FRONT...AS LARGE SCALE MID LEVEL CONVERGENCE MOVES IN FROM THE
NORTHWEST. EVEN IF THE CWA IS SPARED SURFACE-BASED STORMS...IT
STILL LOOKS LIKE A FAIRLY AGGRESSIVE DEVELOPMENT OF AT LEAST
SLIGHTLY ELEVATED STORMS WILL FLARE UP NEAR OR SHORTLY AFTER
SUNSET IN RESPONSE TO INCREASING MOISTURE TRANSPORT/WIND
CONVERGENCE INTO THE MID-LEVEL FRONTAL ZONE EVIDENT AT 700MB.
WHILE HAIL WOULD LIKELY BE THE MAIN THREAT WITH THESE STORMS...THE
MAGNITUDE OF THE SEVERE RISK WILL ULTIMATELY DEPEND ON THE AMOUNT
OF ELEVATED INSTABILITY...WITH THE LATEST NAM ONLY ADVERTISING
LESS THAN 500 J/KG IN THE 850-700MB LAYER...BUT THE GFS STILL
CLOSER TO 1000 J/KG. DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT AT LEAST MARGINAL SEVERE...AVERAGING AROUND 50KT.
CERTAINLY THE MAIN SEVERE THREAT AREA SHOULD FOCUS ACROSS ROUGHLY
THE SOUTHEAST 1/3 OF THE CWA...AND WILL BE MAKING LITTLE CHANGE
TO HAZARDOUS WEATHER OUTLOOK WORDING. EVEN NORTH OF THE MAIN
THUNDERSTORM AREA...WIDESPREAD RAIN SHOWERS SHOULD BREAK OUT
DURING THE NIGHT...AND POPS WERE RAISED TO 70 PERCENT ACROSS
NEARLY THE ENTIRE CWA. ALTHOUGH THE NAM/GFS THERMAL PROFILES
SUGGEST THAT SOME WET SNOW COULD MIX IN WITH RAIN MAINLY IN FAR
NORTHWEST ZONES LATE IN THE NIGHT...WILL KEEP PRECIP TYPE AS ALL
RAIN FOR NOW...DESPITE LOW TEMPS AIMED FROM MID 30S NORTHWEST TO
MID 40S SOUTHEAST.

WEDNESDAY/WEDNESDAY NIGHT...BY THIS TIME THE CWA IS FIRMLY IN THE
GRIPS OF THE COLDER REGIME. THE 00Z ECMWF/GFS RUNS ARE IN BETTER
AGREEMENT THAN 24 HOURS AGO ON THE SYNOPTIC SCENE...AS THEY BOTH
SLOWLY SHIFT THE INCREASINGLY-AMPLIFIED BUT STILL POSITIVELY
TILTED MID-UPPER TROUGH FROM THE NORTHERN PLAINS/CENTRAL ROCKIES
INTO THE CENTRAL PLAINS...WHILE AT THE SURFACE BREEZY NORTH WINDS
PERSIST. THE DOWNWARD NUDGING TO DAYTIME HIGHS CONTINUES...AND NOW
HAVE ALL BUT THE FAR SOUTHEAST CWA ONLY TOPPING OUT SOMEWHERE IN
THE 40S...WITH FURTHER DOWNWARD NUDGES STILL VERY MUCH POSSIBLE
GIVEN THAT PRECIP IS STILL EXPECTED TO BE FAIRLY WIDESPREAD DURING
THE DAY AS THE SOUTHWEST-NORTHEAST ORIENTED MID LEVEL
FRONTOGENETIC ZONE CENTERS OVERHEAD. AT LEAST FOR ONE MORE
FORECAST CYCLE...HAVE LEFT DAYTIME PRECIP TYPE AS RAIN-
ONLY...ALTHOUGH ITS BECOMING INCREASINGLY LIKELY THAT AT LEAST A
MIX WITH SNOW MAY SOON NEED INSERTED ESPECIALLY IN NORTHWEST
AREAS...ESPECIALLY IF HIGH TEMPS CONTINUE A DOWNWARD TREND. BY
THIS TIME INSTABILITY SHOULD BE MINIMAL EVEN IN SOUTHEAST COUNTIES
AND WILL LEAVE OUT THUNDER. POPS WERE UPPED TO 60 PERCENT
LIKELIES IN MOST AREAS...AS THIS IS SHAPING UP TO BE A RATHER WET
AND VERY RAW FIRST DAY OF MAY. WEDNESDAY NIGHT...KEPT AT LEAST
30-50 POPS GOING ALL AREAS FOR A RAIN/SNOW MIX WITH A LIGHT SNOW
ACCUMULATION NOT OUT OF THE QUESTION...ALTHOUGH BOTH THE ECMWF/GFS
ARE IN DECENT AGREEMENT PUSHING PRECIP OUT FROM NORTHWEST-
SOUTHEAST AS THE NIGHT WEARS ON. KEPT LOW TEMPS BARELY ABOVE
FREEZING ACROSS MOST OF THE CWA WEDNESDAY NIGHT...BUT ANY FROST
THREAT WOULD SEEM VERY MINIMAL GIVEN ONGOING PRECIP AND CONTINUED
MODEST NORTH BREEZES.

TURNING TO THE THURSDAY THROUGH SATURDAY TIME FRAME IN LESS
DETAILED FASHION...THE ONE BIT OF GOOD NEWS IS THAT THE ECWMF/GFS
SOLUTIONS ARE NOW IN INCREDIBLY GOOD AGREEMENT...AT LEAST FOR NOW...ON
THE EVOLUTION OF THE TIGHTLY WOUND CLOSED MID LEVEL LOW THAT IS
FORECAST TO DEVELOP ACROSS THE CENTRAL CONUS AS THE PARENT LARGE
SCALE TROUGH AXIS RUNS INTO A SOLID WALL IN THE FORM OF A STOUT
OMEGA BLOCK RIDGE OVER THE EASTERN CONUS. THE BEGINNING STAGES OF
THIS CLOSING OFF PROCESS TAKES PLACE THURS/THURS NIGHT...GENERALLY
CENTERED SOMEWHERE BETWEEN NORTHERN OK AND EASTERN KS. THIS IS
FARTHER EAST IN THE ECMWF FROM PREVIOUS RUNS...WITH THIS MODEL NOW
ACTUALLY KEEPING MOST OF THE CWA DRY FROM THURS AFTERNOON THROUGH
FRIDAY EVENING. HOWEVER...GIVEN PLENTY OF UNCERTAINTY IN THIS
LATEST SOLUTION WILL KEEP LOW POPS FOR EITHER CHILLY RAIN OR A
RAIN/SNOW MIX GOING ACROSS PART OR ALL OF THE CWA THIS ENTIRE TIME
FOR NOW. BY FRIDAY NIGHT INTO SATURDAY...BOTH OF THESE MODELS LIFT
THE CLOSED LOW BACK NORTH FROM MO TOWARD IA...WITH EVEN THE ECMWF
WRAPPING PRECIP CHANCES WESTWARD BACK INTO AT LEAST THE EASTERN
CWA BY THIS TIME. DAILY/NIGHTLY TEMPERATURES WILL DEPEND SO MUCH
ON WHETHER OR NOT WIDESPREAD CLOUDS AND/OR PRECIP ARE
PRESENT...BUT AT LEAST FOR NOW CONTINUED THE DOWNWARD TREND FOR
HIGH TEMPS THURS-SAT...WITH MAINLY UPPER 40S NOW THURS AND LOW 50S
FRI-SAT. OVERNIGHT LOWS BOTH FRI AND SAT MORNING ARE FORECAST
RIGHT AROUND OR JUST BELOW THE 32 DEGREE FREEZING MARK...BUT
HOLDING ABOVE THE 28 DEGREE HARD FREEZE THRESHOLD. AT THE VERY
LEAST...MAY EVENTUALLY HAVE TO INSERT A FROST MENTION FOR FRIDAY
MORNING...BUT CONFIDENCE IS TOO LOW AT THIS TIME RANGE...AND THERE
ARE ALREADY PLENTY MORE IMMEDIATE ISSUES TO DEAL WITH IN THE
SHORTER TERM...SO WILL NOT EXPLICITLY INTRODUCE FROST/FREEZE
CONCERNS IN THE FORECAST PRODUCTS JUST YET. HOWEVER...ITS CERTAINLY
NOT OUT OF THE QUESTION THAT AT LEAST ONE NIGHT MID-LATE NEXT
WEEK COULD REQUIRE A FROST/FREEZE HEADLINE.

&&

.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 125 AM CDT SUN APR 28 2013

ONLY MID-HIGH LEVEL SKY COVER FOR THIS FORECAST. AS THE PRESSURE
GRADIENT INCREASES BY SUNDAY AFTERNOON...A BIT OF A GUST IS
POSSIBLE OUT OF THE WEST AS A DRY LINE MOVES EAST INTO THE
AREA AND A COLD FRONT APPROACHES FROM THE NORTH. SOME
THUNDERSTORMS ARE POSSIBLE TO THE NORTHEAST...BUT SHOULD REMAIN
OUT OF THE AREA.

&&

.FIRE WEATHER...
ISSUED AT 515 AM CDT SUN APR 28 2013

FOR TODAY...THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY
EAST...BUT WILL STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY
SOUTH ACROSS THE CWA...COMING FROM THE NORTHERN PLAINS. WITH
LOWERING DEWPOINTS FOR MUCH OF THE CWA...ALONG WITH THE POTENTIAL
FOR COMPRESSIONAL WARMING AND VERY WARM 850 MB TEMPERATURES...I
HAVE INCREASED HIGH TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID
80S. RELATIVE HUMIDITY SHOULD BE SOLIDLY DRY FOR ITS PART TOWARD
CRITICAL FIRE WEATHER...BUT THE WINDS WILL BE LACKING A BIT...WITH
THE MOST POTENTIAL FOR FIRE ISSUES COMING FROM THE GUSTS AS THE
COLD FRONT MAKES ITS WAY TOWARD THE NORTHWESTERN CWA BY MID-LATE
AFTERNOON.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...HEINLEIN





AREA FORECAST DISCUSSION

NWS BURLINGTON VT

 1023 AM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE OVER THE REGION FOR
THE NEXT UPCOMING SEVERAL DAYS. THERE WILL BE A CHANCE FOR
PRECIPITATION ON MONDAY AND TUESDAY FOR NORTHERN NEW YORK...AS A
TROUGH OF LOW PRESSURE ATTEMPTS TO PUSH THROUGH THE AREA...OTHERWISE
DRY AND WARM CONDITIONS WILL PERSIST.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1023 AM EDT SUNDAY...MINOR ADJUSTMENTS TO SFC DEWPOINTS TO
LOWER VALUES THROUGH THE AFTERNOON HOURS BEFORE RECOVERY LATER
THIS EVENING. RAP PROFILES SHOW DEPTH OF PBL TO AROUND 750 MB
TODAY SO THIS SHOULD MIX DOWN DRIER AIR ACCORDINGLY. OTW INHERITED
FORECAST IN GREAT SHAPE WITH SUNNY/MILD CONDITIONS EXPECTED. HAVE
A GREAT DAY.

PREVIOUS DISCUSSION...A NICE WARM DAY ON TAP FOR THE ENTIRE NORTH
COUNTRY AS HIGH PRESSURE REMAINS OVER THE NEW ENGLAND REGION. TO
OUR NORTH...CLDS FROM WK UPPER TROUGH PERSIST OVER QUEBEC...AND TO
OUR SOUTH LOW PRESSURE OVER THE LOWER TENNESSEE VALLEY. MDLS BEGIN
TO SHIFT RIDGE EASTWARD DURING THE COURSE OF THE DAY ALLOWING FOR
SOUTHERLY FLOW/WAA TO WORK INTO N NY. BUFKIT PROFILES DO SHOW VEIL
OF MID-LEVEL MOISTURE STREAMING NORTH ALONG THE WEST SIDE OF THE
SFC RIDGE BY THE AFTNOON...FUNNELED UP FROM SOUTHERN SYSTEM. WILL
GO FORTH AND BRING SOME CLD COVER FOR N NY DURING THIS TIME FRAME.
THE RESULT OF THESE EXPECTED CLDS WILL DAMPEN SUNSHINE AND THUS
HIGHS IN THAT AREA. OVERALL MID/UPPER 60S IN HIR ELEV AND UP TO
L70S IN VALLEY LOCALES WITH NO PRECIP EXPECTED TDY. GOING INTO
TNGT...SOUTHERLY FETCH PERSISTS THRU PERIOD ALLOWING FOR ABV
NORMAL LOWS RANGING FROM THE M30S FOR DACKS/NE VT TO THE 40S
ELSEWHERE. REMNANTS OF LOW TO OUR SOUTH WILL BE WORKING INTO THE
OHIO VALLEY OVERNGT KEEPING HIGHER CHANCE FOR CLDS OVER N NY AND
LESS FOR CVLY EASTWARD. SOME --RW WILL BEGIN TO DEVELOP OVER SLV
BY 12Z MONDAY AHEAD OF SFC LOW.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
AS OF 342 AM EDT SUNDAY...THE WX FOCUS FOR MONDAY AND TUESDAY
CONTINUES TO BE THE STRONG SFC RIDGE OVER CENTRAL AND EASTERN NEW
ENGLAND. THE REMNANTS OF SFC LOW FROM THE OHIO VALLEY WILL PUSH
INTO WESTERN NY DURING THE DAY. HAVE CONTINUED TREND OF LIGHT -RW
OVER N NY WITH NO EASTWARD PUSH PAST THE CVLY. PRECIP BEGINS TO
WANE GOING INTO THE EVENING/OVERNGT HRS MONDAY AS UPPER/SFC RIDGE
SHIFT BACK WESTWARD. SOME LINGERING --RW FOR WESTERN PORTIONS OF
SLV TUES MORNING ON THE WEST SIDE OF RIDGE...W/ STRONG SUBSIDENCE
FOR EASTERN DACKS/CVLY AND VT. HIGHEST TEMPS FOR MONDAY WILL OCCUR
CVLY EASTWARD AWAY FROM CLD COVER INFLUENCE OF OHIO VALLEY LOW.
OVERALL HIGHS WILL BE IN THE 60S FOR MONDAY AND MAINLY L70S FOR
TUESDAY W/ SOME 60S IN DACKS DUE TO CLD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 317 AM EDT SUNDAY...LITTLE CHANGE IN 00Z NWP GUIDANCE SUITE WITH
RESPECT TO QUIET EXTENDED FCST. PROMINENT MID-TROPOSPHERE OMEGA
BLOCK DEVELOPS ACROSS THE ERN GREAT LAKES INTO SERN ONTARIO/WRN
QUEBEC BRINGING TRANQUIL WEATHER TO THE NORTH COUNTRY THRU
SATURDAY. NO PRECIPITATION FCST. WITH SUBSIDENCE AND MOSTLY CLEAR
SKIES...MODERATELY LARGE DIURNAL TEMPERATURE RANGES ARE FORECAST
WITH HIGHS MAINLY IN THE LOWER 70S AND LOWS IN THE LOW-MID 40S. EXPECT
SLIGHTLY COOLER DAYTIME HIGHS ALONG THE LAKE CHAMPLAIN SHORELINE...PER
WATER TEMP ONLY 40F. FOR OVERNIGHT TEMPS...A FEW MID-UPR 30S
ANTICIPATED IN THE NORMALLY COLDER VALLEYS OF FAR NERN VT AND
WITHIN THE NRN ADIRONDACK REGION.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...VFR. SKC-SCT250 THRU THE DAYLIGHT HRS. HIGH
PRESSURE BRINGS LIGHT AND VARIABLE WINDS EARLY THIS MORNING. AS
RIDGE AXIS SLIDES INTO THE GULF OF MAINE THIS AFTERNOON...WINDS
BECG SE-S AT 5-7 KTS. SOME INCREASE IN MID-LEVEL CLOUDS (10-15
KFT) OVERNIGHT AS MID-LEVEL TROUGH SHIFTS NEWD INTO THE UPR OH
RIVER VALLEY. ANY SHOWER ACTIVITY IS EXPECTED TO REMAIN SOUTH AND
WEST OF THE REGION THRU 12Z MONDAY.

OUTLOOK 12Z MONDAY THROUGH THURSDAY...
12Z MONDAY-12Z TUESDAY...BRIEF INTERVALS OF MVFR POSSIBLE WITH A
FEW RAIN SHOWERS.

12Z TUESDAY-00Z FRIDAY...VFR WITH LIGHT WINDS.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...JN
NEAR TERM...JMG/JN
SHORT TERM...JN
LONG TERM...BANACOS
AVIATION...BANACOS







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 1052 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...TIMING OF PCPN AND CLOUDINESS OVERSPREADING
THE FORECAST AREA THROUGH TONIGHT ARE THE MAIN PARAMETERS NEEDING
UPDATES. EXTRAPOLATED USING THE LATEST TRENDS/LOOPS OF THE 88D
RADAR MOSAIC AND VISIBLE SATELLITE IMAGERY...AND IN ADDITION THE
LATEST HOURLY HRRR UPDATES. STRATIFORM LIGHT RAIN WILL CONTINUE AS
THE MAIN PCPN TYPE...WITH ISOLATED THUNDER POSSIBLE THIS
AFTERNOON THROUGH TONIGHT ASSOCIATED WITH WEAK DYNAMICS FROM THE
PASSAGE OF THOSE WEAK MID LEVEL VORT LOBES. HAVE ALSO UPDATED QPF
FIELDS TO ACCOUNT FOR THE PCPN TIMING...BUT IN GENERAL HAVE KEPT
THE 24 HR AMOUNTS IN TUNE TO THE PREVIOUS FCST.

PREVIOUS DISCUSSION................................................
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SAND HILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...CURRENT RADAR IMAGERY SHOWS SOME -RA MOVING INTO OUR
WESTERN COUNTIES. KFLO/KLBT WILL SEE LIGHT PCPN THIS MORNING...WHILE
DRIER LOW-LEVEL AIR NEAR THE COAST WILL LIKELY PREVENT MUCH FROM
REACHING THE SFC AT KILM/KMYR/KCRE.

A BROAD AREA OF ISENTROPIC ASCENT WILL PRODUCE AREAS OF LIGHT
RAINFALL THAT WILL IMPACT OUR CWA THRU THE DAY. EXPECT MAINLY VFR
CIGS INTO THE AFTN HOURS...BECOMING MVFR INLAND THIS EVENING AS THE
APPROACHING SHORTWAVE BRINGS MORE PCPN TO OUR CWA. RAIN CHANCES
INCREASE AREA-WIDE EARLY MONDAY AS A SFC LOW DEVELOPS OVER THE
WESTERN CAROLINAS. -SHRA IS EXPECTED AFTER 06Z MONDAY ALONG WITH
MVFR CIGS...POSSIBLY NEARING IFR LEVELS INLAND. EAST WINDS AOB 10
KTS THIS MORNING WILL VEER TO THE SOUTHEAST THIS AFTN AND THE
SOUTH OVERNIGHT...LIKELY REMAINING AROUND 10 KTS THROUGHOUT.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
MONDAY AND EARLY TUESDAY. A SLIGHT CHANCE OF SHOWERS LINGERS FOR THE
REST OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...THE NOSE OF HIGH PRESSURE EXTENDING ACROSS
THE EASTERN CAROLINAS FROM THE NE IS PROGGED TO SLIDE JUST
OFFSHORE TODAY AS A WEAK SFC TROF DEVELOPS OVERNIGHT AND EXTENDS
FROM WSW TO ENE ACROSS THE CAROLINAS...MIMICKING A WARM FRONT.
LOOK FOR WINDS TO VEER FROM ENE-E TODAY TO ESE TO SE TONIGHT.
THE LATEST HRRR AND NAM ILLUSTRATE THIS TREND. OVERALL...THIS WILL
CONTINUE THE ONSHORE TYPE FLOW COVERING A DECENT FETCH. EXPECT 3 TO
4 FOOT SIGNIFICANT SEAS TODAY...WITH 5 FOOTERS OFF CAPE FEAR. A 2
TO 3 FOOT ESE GROUND SWELL EXHIBITING 13 TO 15 SECOND PERIODS WILL
DOMINATE SIGNIFICANT SEAS. TWO TO 3 FOOT WIND DRIVEN WAVES AT 5 TO 7
SECOND PERIODS...COULD PUSH SIGNIFICANT SEAS TO 5 FOOT ACROSS A
LARGER REAL ESTATE AREA OTHER THAN THE WATERS OFF CAPE FEAR. WILL
NEED TO MONITOR. STRATIFORM PCPN WILL WEAKEN AND BREAK-UP AS IT
MOVES OFF THE MAINLAND THIS AFTERNOON. HOWEVER...TONIGHT THE PCPN
MOVING OFF THE MAINLAND WILL HAVE BETTER DYNAMICS ALOFT TO WORK
WITH...AND THUS NOT BREAK UP/DISSIPATE.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES
OFF THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT
SHIFTS EAST OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT
BEHIND. WINDS WILL DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH
DIRECTION BECOMING VARIABLE. SEABREEZE WILL INDUCE ONSHORE WINDS
NEAR SHORE ALONG WITH AN INCREASE IN WIND SPEEDS TUE AFTERNOON.
SEAS WILL RUN 3 TO 5 FT EARLY IN THE PERIOD BUT START A SLOW
DECREASE AS WIND SPEEDS START TO DROP LATE MON NIGHT. SEAS WILL BE
2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...
NEAR TERM...DCH/TRA
SHORT TERM...III
LONG TERM...III
AVIATION...BJR
MARINE...







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 749 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SANDHILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...CURRENT RADAR IMAGERY SHOWS SOME -RA MOVING INTO OUR
WESTERN COUNTIES. KFLO/KLBT WILL SEE LIGHT PCPN THIS MORNING...WHILE
DRIER LOW-LEVEL AIR NEAR THE COAST WILL LIKELY PREVENT MUCH FROM
REACHING THE SFC AT KILM/KMYR/KCRE.

A BROAD AREA OF ISENTROPIC ASCENT WILL PRODUCE AREAS OF LIGHT
RAINFALL THAT WILL IMPACT OUR CWA THRU THE DAY. EXPECT MAINLY VFR
CIGS INTO THE AFTN HOURS...BECOMING MVFR INLAND THIS EVENING AS THE
APPROACHING SHORTWAVE BRINGS MORE PCPN TO OUR CWA. RAIN CHANCES
INCREASE AREA-WIDE EARLY MONDAY AS A SFC LOW DEVELOPS OVER THE
WESTERN CAROLINAS. -SHRA IS EXPECTED AFTER 06Z MONDAY ALONG WITH
MVFR CIGS...POSSIBLY NEARING IFR LEVELS INLAND. EAST WINDS AOB 10
KTS THIS MORNING WILL VEER TO THE SOUTHEAST THIS AFTN AND THE
SOUTH OVERNIGHT...LIKELY REMAINING AROUND 10 KTS THROUGHOUT.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
MONDAY AND EARLY TUESDAY. A SLIGHT CHANCE OF SHOWERS LINGERS FOR THE
REST OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...WITH MISSING DATA FROM THE NEARSHORE
WRIGHTSVILLE BEACH BUOY AND FROM THE WAVE GAUGE ON THE OCEAN CREST
PIER AT OAK ISLAND...THIS EARLY MORNING UPDATE IS BASED ON DATA
MAINLY FROM THE FRYING PAN SHOALS BUOY AND FROM NOS PIER SITES AT
WRIGHTSVILLE BEACH AND MYRTLE BEACH. E TO NE WINDS 10 KNOTS
NEARSHORE TO 16 KNOTS OUT AT FRYING PAN SUPPORT MY EARLIER FORECAST.
A GRADUAL VEERING IS EXPECTED THROUGHOUT THE DAY...BEGINNING FIRST
OVER THE SC COASTAL WATERS AND PROCEEDING NORTHWARD THIS AFTERNOON.
NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...

HIGH PRESSURE SITTING OFF THE NEW ENGLAND COAST WILL MOVE LITTLE
THROUGH TONIGHT...MAINTAINING A SURFACE RIDGE JUST WEST OF 70
DEGREES LONGITUDE. A BROAD ZONE OF LOW PRESSURE OVER THE MIDWEST
WILL HELP VEER SURFACE WINDS MORE SOUTHERLY WITH TIME...ESPECIALLY
TONIGHT. THE GRADIENT IS TIGHT ENOUGH TO MAINTAIN AN AVERAGE WIND
SPEED OF 15 KNOTS THROUGH THE PERIOD...WHICH GIVEN THE LONG ONSHORE
TRAJECTORIES WILL MAINTAIN SEAS AT 3-4 FT TONIGHT...BUILDING TO 4-5
FT TONIGHT. BLENDING OUR LOCAL SWAN MODEL WITH WAVEWATCH OUTPUT
PLACES 6 FOOT SEAS JUST OUTSIDE OF THE COASTAL WATERS AT CAPE FEAR
AFTER MIDNIGHT TONIGHT. IF WINDS ARE ONLY A LITTLE STRONGER THAN
FORECAST SMALL CRAFT ADVISORIES MAY BE NEEDED FOR THIS AREA.

SHOWERS DEVELOPING OVER THE GULF STREAM WILL LARGELY DISSIPATE AS
THEY DRIFT WESTWARD OVER THE COOLER CONTINENTAL SHELF WATERS. A
LARGE AREA OF RAIN AND EMBEDDED HEAVIER SHOWERS IS EXPECTED TO PUSH
INTO THE COASTAL WATERS LATE TONIGHT HOWEVER.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES OFF
THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT SHIFTS EAST
OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT BEHIND. WINDS WILL
DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH DIRECTION BECOMING VARIABLE.
SEABREEZE WILL INDUCE ONSHORE WINDS NEAR SHORE ALONG WITH AN
INCREASE IN WIND SPEEDS TUE AFTERNOON. SEAS WILL RUN 3 TO 5 FT EARLY
IN THE PERIOD BUT START A SLOW DECREASE AS WIND SPEEDS START TO DROP
LATE MON NIGHT. SEAS WILL BE 2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...BJR








AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 641 AM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SANDHILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY....STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...MOST OF THE RAIN HAS SHUT OFF AT THIS POINT...BUT A
SERIES OF WEAK DISTURBANCES WILL REGENERATE THE PRECIP BY MORNING.
THINK VISIBILITIES WILL REMAIN VFR...WITH BRIEF PERIODS OF MVFR
POSSIBLE IN MODERATE RAIN SUNDAY. THINK MOST OF THE PRECIP WILL BE
STRATIFORM...HOWEVER EMBEDDED SHOWERS ARE A POSSIBILITY. BEST CHANCE
FOR PRECIP WILL BE TOWARD THE END OF THE FORECAST PERIOD AS DEEPER
MOISTURE AND WEAK ISENTROPIC LIFT ADVECT INTO THE REGION.
PRECIPITATION INDUCED CEILINGS WILL LOWER TO MVFR BY
AFTERNOON...POSSIBLY IFR BY SUNDAY EVENING ALTHOUGH MODELS NOT IN
AGREEMENT WITH THIS SCENARIO.

EXTENDED OUTLOOK...UNSETTLED WEATHER WILL RESULT IN PERIODS OF RAIN
WITH SUB-VFR CONDITIONS POSSIBLE SUNDAY NIGHT THROUGH THURSDAY. THE
BEST RAIN CHANCES WILL BE ON MONDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...WITH MISSING DATA FROM THE NEARSHORE
WRIGHTSVILLE BEACH BUOY AND FROM THE WAVE GAUGE ON THE OCEAN CREST
PIER AT OAK ISLAND...THIS EARLY MORNING UPDATE IS BASED ON DATA
MAINLY FROM THE FRYING PAN SHOALS BUOY AND FROM NOS PIER SITES AT
WRIGHTSVILLE BEACH AND MYRTLE BEACH. E TO NE WINDS 10 KNOTS
NEARSHORE TO 16 KNOTS OUT AT FRYING PAN SUPPORT MY EARLIER FORECAST.
A GRADUAL VEERING IS EXPECTED THROUGHOUT THE DAY...BEGINNING FIRST
OVER THE SC COASTAL WATERS AND PROCEEDING NORTHWARD THIS AFTERNOON.
NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...

HIGH PRESSURE SITTING OFF THE NEW ENGLAND COAST WILL MOVE LITTLE
THROUGH TONIGHT...MAINTAINING A SURFACE RIDGE JUST WEST OF 70
DEGREES LONGITUDE. A BROAD ZONE OF LOW PRESSURE OVER THE MIDWEST
WILL HELP VEER SURFACE WINDS MORE SOUTHERLY WITH TIME...ESPECIALLY
TONIGHT. THE GRADIENT IS TIGHT ENOUGH TO MAINTAIN AN AVERAGE WIND
SPEED OF 15 KNOTS THROUGH THE PERIOD...WHICH GIVEN THE LONG ONSHORE
TRAJECTORIES WILL MAINTAIN SEAS AT 3-4 FT TONIGHT...BUILDING TO 4-5
FT TONIGHT. BLENDING OUR LOCAL SWAN MODEL WITH WAVEWATCH OUTPUT
PLACES 6 FOOT SEAS JUST OUTSIDE OF THE COASTAL WATERS AT CAPE FEAR
AFTER MIDNIGHT TONIGHT. IF WINDS ARE ONLY A LITTLE STRONGER THAN
FORECAST SMALL CRAFT ADVISORIES MAY BE NEEDED FOR THIS AREA.

SHOWERS DEVELOPING OVER THE GULF STREAM WILL LARGELY DISSIPATE AS
THEY DRIFT WESTWARD OVER THE COOLER CONTINENTAL SHELF WATERS. A
LARGE AREA OF RAIN AND EMBEDDED HEAVIER SHOWERS IS EXPECTED TO PUSH
INTO THE COASTAL WATERS LATE TONIGHT HOWEVER.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES OFF
THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT SHIFTS EAST
OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT BEHIND. WINDS WILL
DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH DIRECTION BECOMING VARIABLE.
SEABREEZE WILL INDUCE ONSHORE WINDS NEAR SHORE ALONG WITH AN
INCREASE IN WIND SPEEDS TUE AFTERNOON. SEAS WILL RUN 3 TO 5 FT EARLY
IN THE PERIOD BUT START A SLOW DECREASE AS WIND SPEEDS START TO DROP
LATE MON NIGHT. SEAS WILL BE 2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...43/TRA






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 940 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 932 AM CDT SUN APR 28 2013

UPDATE FOR MINOR CHANGE TO DAYTIME TEMPS/DEWPOINT/SKY COVER. A
COLD FRONT HAS PUSHED INTO NORTHERN NORTH DAKOTA THIS MORNING WITH
A BRISK NORTHWEST WIND BEHIND THE BOUNDARY. NO PRECIPITATION IS
EXPECTED WITH FRONTAL PASSAGE. THE MAIN FORECAST ISSUES CONTINUE
TO BE FLOODING AND FIRE WEATHER...WITH DETAILS BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECMWF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM CDT SUN APR 28 2013

AT 7 AM CDT...A WEAK COLD FRONT WAS ENTERING THE NORTHWEST PORTION
OF THE STATE. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THIS FRONT
TODAY. THE ONLY AVIATION FACTOR WILL BE NORTHWEST WINDS INCREASING
TO 15 TO 25 MPH. VFR EXPECTED AT ALL TAF SITES FOR THE 12Z TAF
PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...RP KINNEY
SHORT TERM...LTH
LONG TERM...WAA
AVIATION...WAA
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH






AREA FORECAST DISCUSSION

NWS BISMARCK ND

 715 AM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 708 AM CDT SUN APR 28 2013

AT 7 AM CDT...A WEAK COLD FRONT WAS POISED TO MOVE THROUGH THE
REGION TODAY. LITTLE PRECIPITATION IS EXPECTED WITH THIS FEATURE
TODAY. SKIES WILL BE PARTLY CLOUDY AND HIGHS WILL BE A BIT COOLER
THAN YESTERDAY. THIS MORNING MAINLY HIGH CLOUDS WERE OVER THE
REGION. REGIONAL RADARS SHOW SCATTERED LIGHT RETURNS...LIKELY ALL
VIRGA. CURRENT FORECAST IS ON TRACK FOR TODAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECWMF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM CDT SUN APR 28 2013

AT 7 AM CDT...A WEAK COLD FRONT WAS ENTERING THE NORTHWEST PORTION
OF THE STATE. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THIS FRONT
TODAY. THE ONLY AVIATION FACTOR WILL BE NORTHWEST WINDS INCREASING
TO 15 TO 25 MPH. VFR EXPECTED AT ALL TAF SITES FOR THE 12Z TAF
PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...LTH
LONG TERM...WAA
AVIATION...WAA
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH







AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 1024 AM CDT SUN APR 28 2013

.UPDATE...
A PESKY BAND OF LOW CLOUDS HAVE BEEN MUCH SLOWER TO DISSIPATE
THAN WE HAD EXPECTED. THIS BAND OF CLOUDS ALONG THE I-20 CORRIDOR
FROM FORT WORTH EAST INTO LOUISIANA AND ALONG THE I-35 CORRIDOR
FROM DENTON TO JUST SOUTH OF WACO...SHOULD MIX OUT EARLY THIS
AFTERNOON. HAVE UPDATED THE CLOUD COVER AND HOURLY TEMPERATURE
FORECASTS TO ACCOUNT FOR THE CLOUDS. A WARM FRONT THAT EXTENDED
FROM NORTH OF LAMPASAS TO JUST SOUTH OF LUFKIN WILL MOVE NORTH
TODAY. LIGHT MOSTLY EAST TO SOUTHEAST WINDS TO THE NORTH OF THE
FRONT WILL BECOME SOUTHERLY AT AROUND 10 MPH AS THE FRONT MOVES
THROUGH. TEMPERATURES WILL STILL WARM INTO THE UPPER 70S TO MID
80S ACROSS THE REGION THIS AFTERNOON.

58

&&

.AVIATION...
MVFR VISIBILITY RESTRICTIONS ARE LIKELY TO CONTINUE AT WACO
THROUGH 14 OR 15Z. BR IS PRESENT AROUND THE METROPLEX...BUT URBAN
HEAT ISLAND IS KEEPING TEMPERATURES HIGHER AND CONDITIONS CLEAR.
CANT RULE OUT BRIEF RESTRICTIONS JUST AFTER DAYBREAK...BUT
PROBABILITIES WERE TOO LOW TO MENTION IN THE TAF. PROBABILITIES
WOULD BE GREATEST AT KGKY...KFTW AND KAFW. OTHERWISE...WINDS WILL
BECOME SOUTHERLY TODAY...AND SKIES WILL REMAIN MOSTLY CLEAR. THERE
HAVE BEEN A FEW PATCHES OF MVFR CLOUDS AROUND THE AREA
OVERNIGHT...BUT COVERAGE ISNT HIGH ENOUGH TO WARRANT A MENTION IN
THE TAFS. COULD SEE A REPEAT OF BR FOR WACO TOMORROW MORNING...BUT
WIND SPEEDS WILL BE HIGHER...WHICH WILL LIMIT THE FOG POTENTIAL.

HAMPSHIRE


&&



.PREV DISCUSSION... /ISSUED 359 AM CDT SUN APR 28 2013/

REGIONAL RADAR MOSAIC SHOWS A BROAD AREA OF CONVECTION EXTENDING
FROM BRYAN SOUTHWEST ALONG THE TX GULF COAST TO CORPUS CHRISTI
EARLY THIS MORNING. 08Z /3AM/ SURFACE OBSERVATIONS SHOWED A
DIFFUSE FRONTAL BOUNDARY LOCATED JUST SOUTHEAST OF A LINE FROM
TEMPLE TO PALESTINE. THE BOUNDARY WAS MOST EVIDENT IN THERMAL AND
MOISTURE FIELDS AS LOW LEVEL WINDS HAVE ALREADY STARTED TO COME
AROUND TO THE SOUTHEAST TO THE NORTH OF THE FRONT. WATER VAPOR
SATELLITE IMAGERY SHOWED A COMPACT UPPER LOW OVER THE IN/IL BORDER
MOVING EAST-NORTHEAST EARLY THIS MORNING. WATER VAPOR IMAGERY ALSO
SHOWED A CYCLONIC SHEAR AXIS OR TROUGH TRAILING BEHIND THE UPPER
LOW TO THE SOUTHWEST. THIS TROUGH WAS LOCATED OVER THE CWA AS OF
08Z AND WAS MOVING SLOWLY SOUTHEAST. ALONG THE DIFFUSE FRONTAL
BOUNDARY...IR SATELLITE IMAGERY SHOWED MOSTLY CLOUDY SKIES WHICH
WAS HELPING TO KEEP TEMPERATURES IN THE LOWER TO MID 60S NEAR THE
FRONT. TO THE NORTHWEST OF THE FRONT THERE WAS A SHARP CUT-OFF IN
CLOUD COVER...ALLOWING TEMPERATURES TO FALL INTO THE 50S FOR MOST
OF NORTH TX EARLY THIS MORNING.

TODAY...THE UPPER LEVEL TROUGH IS EXPECTED TO SLOWLY MOVE
SOUTHEAST OF THE CWA TODAY...SPREADING WEAK LARGE SCALE FORCING
FOR SUBSIDENCE OVER THE AREA. SURFACE WINDS ARE EXPECTED TO RETURN
TO THE SOUTH TODAY WHICH MAY CAUSE THE WEAK FRONTAL BOUNDARY TO
LIFT NORTH ACROSS THE CWA THIS AFTERNOON. IT IS DIFFICULT TO
DETERMINE IF THIS WILL BE OF ANY CONSEQUENCE... BECAUSE THE RETURN
TO SOUTH WINDS UNDER MOSTLY SUNNY SKIES WILL MORE OR LESS
ELIMINATE ANY THERMAL GRADIENT/BAROCLINICITY ASSOCIATED WITH THE
FRONT.

BY DEFINITION THIS BOUNDARY WOULD NOT COUNT AS A FRONT ANYMORE
WITHOUT A DISCERNABLE THERMAL GRADIENT. HOWEVER...THERE WILL STILL
BE SOME SORT OF MOISTURE DISCONTINUITY ASSOCIATED WITH THE
BOUNDARY AS IT LIFTS NORTH TODAY...LIKELY RESULTING IN A SLIGHT
INCREASE IN RELATIVE HUMIDITY. NORMALLY THIS WOULD HAVE LITTLE
IMPACT ON THE FORECAST...BUT TODAY THE NAM AND RAP FORECAST
SOUNDINGS INDICATE THAT THE AFTERNOON INCREASE IN LOW-LEVEL
HUMIDITY IS SUFFICIENT TO RESULT IN AN ALMOST COMPLETE REMOVAL OF
THE CAP FROM THE FORECAST AREA DURING THE PEAK HEATING HRS OF THE
DAY. WITH NO CAP...IT IS POSSIBLE THAT SOME WEAK FORCING FOR
ASCENT COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS NORTH TX BY
LATE THIS AFTERNOON.

AT THIS TIME...LEFT THE FORECAST DRY BECAUSE OF A LACK OF
DISCERNABLE FOCUS FOR THUNDERSTORM INITIATION THIS AFTERNOON. THE
SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH IS EXPECTED TO BE
WEAK...BUT IN THE ABSENCE OF STRONG MESOSCALE FORCING FOR
ASCENT...THIS SHOULD BE SUFFICIENT TO KEEP US DRY DESPITE A NEARLY
UNCAPPED AFTERNOON THERMODYNAMIC ENVIRONMENT. OTHERWISE...WITH
MOSTLY SUNNY SKIES AND A RETURN TO SOUTH WINDS TODAY EXPECT
TEMPERATURES TO CLIMB INTO THE 80S FOR MOST LOCATIONS DESPITE THE
COOL START TO THE DAY THIS MORNING.

MONDAY AND TUESDAY...THE ECMWF/GFS/CANADIAN NOW ALL SHOW THE THAT
THE WESTERN EDGE OF OUR SOUTHEASTWARD MOVING TROUGH TODAY EVOLVES
INTO AN UPPER LEVEL CLOSED LOW OVER THE TX GULF COAST MONDAY INTO
TUESDAY. THIS WEAK UPPER LOW WILL LIKELY CAUSE CLUSTERS OF STORMS
TO DEVELOP EACH DAY ACROSS FAR SOUTH TX OR ALONG THE TX GULF
COAST...LIKELY WORKING TO REINFORCE THE UPPER LEVEL CIRCULATION
THROUGH THE PERIOD. DUE TO THE FORECAST POSITION OF THE UPPER LOW
TO OUR SOUTH...THIS FEATURE SHOULD ONLY REINFORCE UPPER LEVEL
SUBSIDENCE OVER THE CWA HELPING TO KEEP US DRY FOR EARLY THIS
WEEK. PERSISTENT SOUTHERLY FLOW WILL CONTINUE CAUSING SHALLOW GULF
MOISTURE TO REMAIN IN PLACE OVER THE CWA...BUT THUNDERSTORM
CHANCES SHOULD BE VERY LOW AS LONG AS THE UPPER LOW OVER THE GULF
COAST EVOLVES AS EXPECTED. AT ANY RATE...MOSTLY SUNNY SKIES AND
PERSISTENT SOUTHERLY FLOW WILL KEEP US ABOVE NORMAL FOR
TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S EACH DAY.

WEDNESDAY THROUGH FRIDAY...A POWERFUL UPPER LOW FROM THE GULF OF
ALASKA IS STILL EXPECTED TO MOVE SOUTHEAST OVER THE PLAINS
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SEND AN UNSEASONABLY
STRONG COLD FRONT SOUTH THROUGH THE PLAINS AND ACROSS NORTH TEXAS
LIKELY WEDNESDAY EVENING AND OVERNIGHT. AS LONG AS THE UPPER LOW
DIGS AS FAR SOUTH AS THE RED RIVER...WHICH IS ADVERTISED BY THE
OPERATIONAL ECMWF/GFS/CANADIAN...THERE SHOULD BE A NEARLY SOLID
LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANYING THE FRONT. THE FRONT
IS EXPECTED TO MOVE THROUGH THE AREA VERY FAST...SO OVERALL
RAINFALL AMOUNTS WILL LIKELY BE SMALL...BUT MOST LOCATIONS SHOULD
AT LEAST SEE SOME LIGHT RAIN AS THE FRONT MOVES THROUGH THE AREA.
BUMPED UP POPS INTO THE 40 TO 50 PERCENT RANGE ALONG AND BEHIND
THE FRONT AS A RESULT. DID NOT GO HIGHER AT THIS TIME BECAUSE OF
UNCERTAINTY REGARDING THE TIMING OF THE FRONT. WHILE OPERATIONAL
MODELS ARE CONSISTENT WITH THE FRONTAL PASSAGE RIGHT NOW...THE
FRONT IS STILL AT LEAST 84 HRS OUT...AND OUR MEDIUM RANGE GUIDANCE
IS NOTORIOUSLY BAD AT PREDICTING THE TIMING OF STRONG COLD FRONTS.
THEREFORE WILL CONTINUE TO REFINE POPS AND THE TIMING OF THE FRONT
IN FUTURE FORECASTS.

SEVERE WEATHER CHANCES OUT AHEAD OR ALONG THE FRONT DO NOT LOOK
GREAT PRIMARILY BECAUSE OF THE PROGGED FAST MOTION OF THE FRONT
THROUGH THE PLAINS. SOME SEVERE WEATHER MAY BE ADDED TO THE
FORECAST AS THE FRONT GETS CLOSER...BUT FOR NOW THE OVERALL
PATTERN DOES NOT SEEM TO SUPPORT A REGIONAL OUTBREAK OF SEVERE
STORMS...SO WILL NOT HIGHLIGHT ANY SEVERE WEATHER IN PRODUCTS AT
THIS TIME. TEMPERATURES BEHIND THE FRONT ARE EXPECTED TO BE VERY
COLD FOR EARLY MAY...WITH RECORD LOW TEMPERATURES LIKELY BEHIND
THE FRONT THURSDAY NIGHT. RECORD LOWS THURSDAY NIGHT WILL HELP
KEEP TEMPERATURES COOL HEADED INTO THE WEEKEND.

THIS WEEKEND...THE ECMWF IS LESS BULLISH WITH ITS FORECAST OF A
BLOCKING PATTERN THAT WOULD KEEP THE UPPER LOW ANCHORED IN THE
CENTRAL PLAINS FOR SEVERAL DAYS. THE NAEFS IS ALSO LEANING MORE
TOWARDS THE UPPER LOW MOVING NORTHEAST OUT OF THE REGION BY EARLY
NEXT WEEK. THAT SAID...THE NAEFS MEAN AND THE LAST EVENING RUN OF
THE ECMWF BOTH KEEP GENERAL TROUGHINESS OVER THE CENTRAL
CONUS...MEANING TEMPERATURES WILL LIKELY BE NEAR OR MAYBE SLIGHTLY
BELOW SEASONAL NORMALS. AFTER NEAR RECORD OR RECORD LOWS THURSDAY
NIGHT/FRIDAY MORNING...THERE IS LITTLE PLACE FOR THE TEMPERATURES
TO GO BUT UP. TEMPERATURES WILL MODERATE BACK TOWARDS SEASONAL
NORMALS THIS WEEKEND INTO EARLY NEXT WEEK...AND NOT JUST BECAUSE
MOS GUIDANCE TRENDS TOWARDS CLIMATOLOGY OUT ON DAY 7. THICKNESS
AND HEIGHT RISES WILL HELP USHER IN WARMER TEMPERATURES AS LONG AS
THE UPPER LOW DOES MOVE NORTHEAST OF THE PLAINS BY EARLY NEXT
WEEK. THE EXTENDED FORECAST IS DRY FOR NOW...HOWEVER WITH GENERAL
CYCLONIC FLOW IN PLACE THERE WILL UNDOUBTEDLY BE SOME SMALL
FEATURES THAT NECESSITATE THE INCLUSION OF PRECIPITATION DURING
THIS PERIOD IN FUTURE FORECASTS. AT THIS TIME THERE IS JUST NOT
ENOUGH CONSISTENCY TO PLACE POPS IN ONE PERIOD OVER ANOTHER...SO
LEFT THE FORECAST DRY WITH 10 POPS IN PLACE FOR SEVERAL DAYS.

CAVANAUGH



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  84  61  86  63  87 /  10   0   0   0   5
WACO, TX              84  58  84  60  86 /  10   0   0   0   5
PARIS, TX             79  55  83  58  84 /  10   0   0   0   5
DENTON, TX            83  58  87  59  87 /  10   0   0   0   5
MCKINNEY, TX          82  58  84  60  86 /  10   0   0   0   5
DALLAS, TX            83  62  86  64  87 /  10   0   0   0   5
TERRELL, TX           82  57  83  59  84 /  10   0   0   0   5
CORSICANA, TX         82  58  83  59  84 /  10   0   0   0  10
TEMPLE, TX            83  57  83  59  85 /  10   5   0   0   5
MINERAL WELLS, TX     83  58  86  59  87 /  10   0   0   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

84/58












AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 423 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO WEAKEN TONIGHT...AS SEVERAL MID
LEVEL DISTURBANCES PROGRESS OVER OR NEAR THE LOCAL AREA. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL ADVANCE THROUGH THE REGION BY
TUESDAY...AS STRENGTHENING HIGH PRESSURE BUILDS FROM THE NORTH THE
SECOND PART OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY FOUND ACROSS THE FAR
SOUTHWEST ZONES THIS AFTERNOON..THE EXCEPTION BEING SOME SHOWER
ACTIVITY ORIGINATING FROM THE NEARBY ATLANTIC THAT PUSHED INTO THE
CHARLESTON COUNTY COAST FROM CONVERGENCE OFFSHORE. NUMERICAL MODEL
SOLUTIONS HAVE STRUGGLED TO ACCURATELY REPRESENT THE COVERAGE OF
PRECIPITATION TODAY...RESULTING IN LOWER CONFIDENCE WITH THE
EVOLUTION OF ONGOING SHOWER ACTIVITY AND THE INITIATION OF NEW
CONVECTION. ONLY THE HIGH RESOLUTION HRRR MODEL SEEMS TO HAVE A
DECENT OVERVIEW OF THE SHOWER COVERAGE...AND WILL THUS LEAN TOWARD
ITS REPRESENTATION OF THE PRECIPITATION SCENARIO FOR THE NEAR TERM
PERIOD.

SHOWERS CURRENTLY IN THE AREA HAVE STRUGGLED TO INTENSIFY WITHIN
ONLY MARGINAL INSTABILITY SEEN IN MOST RECENT STORM PREDICTION
CENTER MESOANALYSIS. THE STRONGEST SHORTWAVE ENERGY DOWNSTREAM OF
THE MAIN UPPER TROUGH TO THE WEST HAS REMAINED TO THE WEST AND
NORTHWEST OF THE FORECAST AREA. HOWEVER...CONSIDERING SEVERAL MORE
HOURS OF DAYLIGHT MAINTAINING SOME INSTABILITY...AS WELL AS THE
POTENTIAL SEABREEZE AND OUTFLOW BOUNDARY INTERACTIONS...INLAND
THUNDERSTORMS COULD CONTINUE TO DEVELOP AND POSSIBLY INTENSIFY
THROUGH THE AFTERNOON. ANY STORMS THAT BECOME STRONG AND ORGANIZED
COULD PRODUCE GUSTY WINDS AND SMALL HAIL...ESPECIALLY WHERE
BOUNDARY INTERACTIONS OCCUR.

EVEN WITH A POTENTIAL LULL IN RAIN COVERAGE THIS EVENING AFTER
DIURNAL INSTABILITY HAS WANED...THE APPROACHING UPPER TROUGH WILL
FINALLY BE ABLE TO SUPPRESS RIDGING ALONG THE EAST COAST AND ALLOW
SHORTWAVE ENERGY TO CROSS INTO THE FORECAST AREA. AT THAT
POINT...NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT MORE
WIDESPREAD PRECIPITATION WILL IMPACT THE REGION. WILL SHOW
INCREASING RAIN CHANCES FROM WEST TO EAST ACCORDINGLY...WHILE
MAINTAINING MENTION OF JUST A SLIGHT CHANCE FOR THUNDER OVERNIGHT.

WARM ADVECTION WITHIN SOUTHERLY FLOW OVERNIGHT...COMBINED WITH THE
INSULATING EFFECTS OF THICK CLOUD COVER...WILL KEEP LOW
TEMPERATURE QUITE MILD. EXPECT TEMPERATURES TO ONLY FALL INTO THE
LOW TO MID 60S.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MODELS CONTINUE TO INDICATE THE POTENTIAL FOR UNSETTLED WEATHER
THROUGH THIS PERIOD. FOR MONDAY...AND UPPER LEVEL TROUGH WILL BE
WEAKENING AS IT MOVES NORTH AND EAST OF THE REGION. AMPLE MOISTURE
AND SOME WEAK LIFT ASSOCIATED WITH UPPER TROUGH SHOULD BE ENOUGH
TO SPARK NUMEROUS SHOWERS AND SOME THUNDERSTORMS...ESPECIALLY DURING
PEAK AFTERNOON HEATING. HAVE MAINTAINED HIGH END LIKELY TO LOW END
CATEGORICAL POPS...WITH THE HIGHEST POPS OVER THE NORTHERN/SC ZONES.
PW VALUES AROUND 1.5 INCHES...ALONG WITH DEEP LAYER SSW FLOW COULD
TRANSLATE INTO THE CHANCE FOR SOME LOCALLY HEAVY RAINFALL.

THE FORECAST PROBLEM BEGINNING AS SOON AS MONDAY NIGHT IS THAT THE
GLOBAL MODELS BEGIN TO DIVERGE FROM THE GRIDDED/NAM MODEL. THE
GENERAL TREND IN THE GLOBAL MODELS IS TO MOVE THE UPPER TROUGH WELL
NE OF THE REGION LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...TAKING
WITH IT THE BULK OF THE DEEP LAYER MOISTURE AND PRECIP CHANCES.
HOWEVER...THE NAM IS SLOWER WITH MOVING OUT THE UPPER TROUGH TO THE NE
AND ALSO HOLDS A MUCH STRONGER INVERTED TROUGH OVER THE NEARSHORE
ATLANTIC WATERS THROUGH MID WEEK. THE STRONGER SURFACE INVERTED
TROUGH OVER THE ATLANTIC WATERS SEEMS TO BE IN RESPONSE TO A
DEVELOPING WEAK/CLOSED UPPER LOW TO THE SW OVER THE GULF STATES.
THEREFORE...THE NAM SOLUTION LOOKS MUCH WETTER THROUGH THE PERIOD
THAN THE GLOBAL MODELS. FOR NOW...HAVE TRENDED POPS UP FROM PREVIOUS
FORECAST...GENERALLY IN THE CHANCE RANGE...BUT STILL MUCH LOWER THAN NAM
WOULD SUGGEST.

STABILITY PROFILES SEEM PRETTY MARGINAL TO SUPPORT MUCH THUNDER
THROUGH THE PERIOD...BUT HAVE KEPT CHANCE TO SLIGHT CHANCE MAINLY IN
THE AFTERNOONS.

THE TEMPERATURE FORECAST IS CHALLENGING DUE TO THE UNCERTAINTY IN
PRECIP CHANCES AND CLOUD COVER DEPICTED BY THE MODELS. HAVE MADE
ONLY SLIGHT CHANGES TO THE PREVIOUS FORECASTS...GENERALLY UPPER 70S
TO NEAR 80 AND UPPER 50S TO LOWER 60S FOR LOWS. THESE VALUES ARE
NEAR NORMAL. WILL NEED TO MONITOR LATER FORECAST TRENDS...SINCE A
SOLUTION MORE LIKE THE NAM WOULD LIKELY TRANSLATE INTO LOWER MAXES
AND HIGHER MINS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODERATE TO HIGH FORECAST UNCERTAINTY CONTINUES INTO THE EXTENDED
PERIOD. AN IMPRESSIVE BLOCKING PATTERN WILL PREVAIL OVER THE EASTERN
CONUS INTO NEXT WEEKEND. THE SOUTHERN EXPANSE OF THE BLOCKING RIDGE
AND ASSOCIATED INTERACTION OF THE UPPER LOWS OVER THE LOWER
MISSISSIPPI RIVER VALLEY...THE WESTERN ATLANTIC AND THE GREAT PLAINS
REMAINS UNCLEAR. DID SOME MINOR TWEAKS TO THE POPS/WINDS/TEMPS
THROUGH THURSDAY NIGHT TO BLEND BETTER WITH THE SHORT TERM FORECAST.
HOWEVER...MAINTAINED SLIGHT CHANCE/CHANCE POPS THROUGH THE PERIOD
ESPECIALLY GIVEN THE 28/00Z EUROPEAN SOLUTION DEPICTING A PERSISTENT
BAND OF MOISTURE ON THE SOUTHERN PERIPHERY OF THE RIDGE/OVER OR
CLOSE TO SOUTH/WESTERN COUNTIES OF THE FORECAST AREA
WEDNESDAY/THURSDAY...FOLLOWED BY EASTERN PROGRESSION OF THE GREAT
PLAINS UPPER LOW TOWARD THE EAST PUSHING ENHANCED MOISTURE FARTHER
INTO THE FORECAST AREA LATE WEEK/NEXT WEEKEND. HOWEVER...IF THE DEEP
LAYER BLOCKING RIDGE EXPANDS FARTHER SOUTH ACROSS THE
REGION...MOISTURE COULD BE FORCED OUTSIDE THE FORECAST AREA
RESULTING IN DRIER CONDITIONS.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR IS EXPECTED FOR MUCH OF THE PERIOD...HOWEVER MODEL SOUNDINGS AND
GUIDANCE ONCE AGAIN HINT AT MVFR CEILINGS DEVELOPING OVERNIGHT
INTO MONDAY MORNING. CONFIDENCE IN THIS OCCURRING IS TOO LOW TO
MENTION AT THIS TIME...AND WILL JUST LEAN TOWARD THIS POTENTIAL BY
INCLUDING SCATTERED MVFR CLOUDS LATE TONIGHT. THE OTHER AVIATION
CONCERN IS SHOWERS AND THUNDERSTORMS AFFECTING THE TERMINALS.
MODELS ARE STILL NOT HANDLING CURRENT SITUATION VERY WELL...SO
DETERMINING COVERAGE AND TIMING IS QUITE DIFFICULT. WILL NEED TO
MONITOR THIS AFTERNOON...AND AMENDMENTS WILL LIKELY BE NEEDED AS
TRENDS BECOME BETTER DEFINED. REDUCED VSBYS/CIGS ARE POSSIBLE
WITHIN HEAVIER RAINFALL.

EXTENDED AVIATION OUTLOOK...OCCASIONAL FLIGHT RESTRICTIONS POSSIBLE
DUE TO SHOWERS/RICH LOW LEVEL MOISTURE MONDAY INTO TUESDAY MORNING.
VFR CONDITIONS SHOULD THEN PREVAIL MUCH OF THE TIME THROUGH LATE
WEEK...BUT FORECAST CONFIDENCE IS NOT HIGH.

&&

.MARINE...
TONIGHT...SURFACE HIGH PRESSURE TO THE NORTH WILL RETREAT FARTHER
INTO THE ATLANTIC. MODERATE SOUTHEAST FLOW WILL STEADILY VEER MORE
TO THE SOUTH TONIGHT. THE PRESSURE GRADIENT WILL TIGHTEN SUFFICIENTLY
TO SUPPORT WIND SPEEDS AT 15 KT OVERNIGHT WITH A FEW GUSTS TO 20 KT.
FOR THE MOST PART...SIGNIFICANT WAVE HEIGHTS WILL REMAIN CAPPED AT
4 OR 5 FT. MARINERS CAN EXPECT ISOLATED TO SCATTERED SHOWERS
TONIGHT WITH A SLIGHT CHANCE FOR THUNDER.

MODELS SHOW A CONSIDERABLE AMOUNT OF UNCERTAINTY THROUGH MUCH OF THE
WEEK. THE NAM HOLDS A STRONGER SURFACE COASTAL TROUGH OF LOW
PRESSURE OVER THE NEARSHORE WATERS LATER TUESDAY THROUGH AT LEAST
WEDNESDAY. HOWEVER...THE GLOBAL MODELS ALL INDICATE A MUCH WEAKER
COASTAL TROUGH OF LOW PRESSURE...WHILE BUILDING STRONGER HIGH
PRESSURE IN FROM THE NORTH. THIS MAKES FOR A DIFFICULT WIND
FORECAST. FOR NOW...HAVE BLENDED THE MODEL SOLUTIONS AS BEST AS
POSSIBLE...WHICH ALSO COLLABORATES REASONABLY WELL WITH SURROUNDING
OFFICES.

FOR MONDAY AND MONDAY NIGHT...KEPT SOUTHERLY WINDS OF GENERALLY
15 KT OR LESS WITH SEAS 3 TO 5 FT. THE GFS IS INDICATING SEAS
COULD REACH 6 FT OFFSHORE GA...BUT HAVE CAPPED TO 5 FT DUE TO
UNCERTAINTY IN WIND FORECAST. SCATTERED TO NUMEROUS SHOWERS AND
SOME THUNDERSTORMS EXPECTED.

TUESDAY THROUGH THURSDAY IS WHERE MODELS BEGIN TO DIVERGE. THE NAM
PRODUCES A STRONGER COASTAL TROUGH OF LOW PRESSURE OVER THE
NEARSHORE WATERS THROUGH AT LEAST WEDNESDAY...WHILE THE GLOBAL
MODELS SHOW A MUCH WEAKER COASTAL TROUGH...AND BUILD IN A STRONGER
HIGH PRESSURE FROM THE NORTH...ESPECIALLY WEDNESDAY AND THURSDAY.
 FOR NOW HAVE BLENDED THE MODEL SOLUTIONS AS BEST AS POSSIBLE...AND
KEPT WINDS AND SEAS BELOW ANY HIGHLIGHTS DUE TO UNCERTAINTY.
HOWEVER...MARINE CUSTOMERS SHOULD STAY TUNED TO THE LATEST UPDATES
AS DUE TO FORECAST UNCERTAINTY...BY MID WEEK.

RIP CURRENTS...EXPECT A MODERATE RISK TO CONTINUE INTO MONDAY DUE TO
LONG PERIOD SWELL...SOUTHERLY FLOW AND SOME LINGERING ASTRONOMICAL
INFLUENCES.

STRENGTHENING ONSHORE WINDS AND BUILDING SEAS COULD AGAIN PRODUCE
AN ELEVATED RISK OF RIP CURRENTS LATER THIS WEEK INTO NEXT WEEKEND.

&&

.TIDES/COASTAL FLOODING...
WILL NEED TO CLOSELY MONITOR FOR POSSIBLE SHALLOW COASTAL FLOODING
ALONG THE CHARLESTON COUNTY COAST WITH THE HIGH TIDE TONIGHT...AS
TIDES CONTINUE TO RUN ABOVE PREDICTED LEVELS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...WMS
SHORT TERM...RFM
LONG TERM...RFM/SPR
AVIATION...ECT/RFM
MARINE...RFM/WMS
TIDES/COASTAL FLOODING...WMS







AREA FORECAST DISCUSSION

NWS LINCOLN IL

 105 PM CDT SUN APR 28 2013

.DISCUSSION...
ISSUED 1038 AM CDT SUN APR 28 2013
LOW CENTER IN EAST CENTRAL INDIANA THIS MORNING...WITH LOW
STRATUS...DRIZZLE...AND COOL TEMPERATURES DOMINATING CENTRAL
ILLINOIS. WESTERN EDGE OF THE LOWEST CEILINGS ERODING SLOWLY ON
VIS AND IR SAT IMAGERY. MISS RIVER VALLEY NORTH OF QUINCY UNDER
MOSTLY SUNNY SKIES. WATCHING SUNNY SKIES BUILD SLOWLY
EASTWARD...NW OF THE ILLINOIS RIVER VALLEY LIKELY TO SEE SOME SUN
AND MAX TEMPS IN UPPER 60S/NEAR 70 AS A RESULT. FURTHER TO THE
EAST CLOSER TO THE LOW...A BIT MORE PROBLEMATIC. NOT ANTICIPATING
A SIGNIF LOSS OF CLOUD COVER...AND KEEPING COOLER TEMPS IN AS A
RESULT. SOME MINOR ADJUSTMENTS TO THE FORECAST AND THE HOURLY
GRIDS...THOUGH REISSUANCE NOT ANTICIPATED UNTIL MAYBE AFTER NOON
TO CLEAN UP SOME MORNING WORDING.



&&

.AVIATION...
ISSUED 1254 PM CDT SUN APR 28 2013
SFC LOW NOT MAKING MUCH FORWARD PROGRESS...LEAVING IFR/LIFR
CONDITIONS IN MUCH OF CENTRAL IL. BACK EDGE OF STRATUS DISCERNIBLE
ON VIS/IR SAT IMAGERY. MVFR CONDITIONS CREEPING IN TO SPI AND PIA
AT TAF ISSUANCE...AND SHOULD CONTINUE TO SEE AN IMPROVEMENT OF
CONDITIONS THROUGH THE AFTERNOON...THOUGH OTHER TERMINALS WILL
STRUGGLE FOR IMPROVEMENT LATE BEFORE SUNSET. BIG QUESTION WILL BE
HOW DENSE THE FG/BR OVERNIGHT. WITH PIA SEEING CLEARING
ALREADY...AND THROUGH THE NIGHT...GOOD CHANCE FOR A VIS DROP
THERE. SPI STILL TRYING TO BREAK OUT BUT SURROUNDED BY SOME
LINGERING STRATUS...WILL DEPEND ON HOW MUCH CLEARS OUT THIS
EVENING...AND SAME MENTALITY APPLIES TO OTHER LOCATIONS...THOUGH
CMI AND BMI MAY BE CLOSE ENOUGH TO THE LOW STILL TO KEEP DEGRADED
CONDITIONS IN PLACE. PIA AND SPI MVFR/VFR THROUGH AFTERNOON...DEC
AND BMI IFR...AND CMI WILL LIKELY SEE A BIT OF A DROP IN ITS
VARIABLE CONDITIONS AS LOWER CLOUDS MOVE IN.


HJS
&&

.PREV DISCUSSION...
ISSUED 259 AM CDT SUN APR 28 2013

FORECAST PROBLEMS THIS MORNING IS THE LINGERING PCPN FOR THIS
MORNING...POSSIBLE CLOUD COVER/CLEARING AND FOG SUNDAY NIGHT...AND
THEN THE CLOSING OFF OF AN UPPER LOW MIDWEEK AND ASSOCIATED PCPN.

SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
UPPER AIR DATA...IR SATELLITE...AND THE RADAR LOOP SHOWS EASTERN
MO LOW CENTER AT 00Z...HAD DRIFTED TO THE EAST TO THE AREA AROUND
STL. 00Z UPPER AIR SHOWS DEEP LOW LEVEL MOISTURE AXIS UP THE MS
VALLEY AREA AHEAD OF UPPER FEATURE. WITH 300MB JET SOUTH OF UPPER
LOW...SYSTEM SHOULD CONTINUE TO TRACK EAST...WITH THE FETCH OF
MOISTURE NOW TO THE EAST INTO OH VALLEY REGION. RAP AROUND
MOISTURE/SHOWERS STILL EXPECTED TO GRADUALLY TRANSLATE TO THE EAST
WITH LOW TODAY...WITH SOME CLOUD BREAKUP POSSIBLE IN THE EXTREME
WESTERN PARTS OF CWA. MODIFIED POPS FOR TODAY WITH A GRADUAL SHIFT
TO THE EAST TODAY OF THE LOW. LOWERED HIGHS FOR TODAY OVER ALL BUT
NORTHWEST TO GO WITH EXTENSIVE CLOUD COVER OVER ALL BUT WHERE SOME
CLEARING MAY BE IN NORTHWEST. DUE TO CLEARING TONIGHT...REGION
EAST OF IL RIVER WILL HAVE POSSIBLE FOG DEVELOPMENT OVERNIGHT DUE
TO PLENTY OF OVERNIGHT RAIN AND CLOUD COVER TODAY NOT ALLOWING MIX
OUT OF LOW LEVEL MOISTURE.

A WEAK FRONT APPROACHES THE REGION MONDAY NIGHT...BRINGING A CHANCE
OF PCPN TO THE NORTHWEST SECTIONS. THE FRONT THEN WASHES OUT AND WE
REMAIN DRY IN THE WARM SECTOR TIL WED.

LONG TERM...WEDNESDAY THROUGH SUNDAY...
AN UNSETTLED PERIOD STARTS MIDWEEK AND LASTS TO WEEKEND. AN UPPER
WAVE MOVING THROUGH THE GREAT LAKES TUESDAY NIGHT DRAGS A FRONT
INTO THE MO TO NORTHERN IL REGION. THEN A MAJOR UPPER TROUGH IS
PROGGED TO DIG INTO THE WESTERN PLAINS...CLOSING OFF IN THE
SOUTHERN PLAINS. THE FRONTAL SYSTEM STALLS IN THE MID MS RIVER
VALLEY FROM WED NIGHT INTO THE WEEKEND WITH SCATTERED PCPN ALONG
THE SYSTEM. MODELS HAVE BECOME A LITTLE MORE CONSISTENT AND IN
AGREEMENT WITH THIS SCENARIO...WITH AN UPPER LOW THEN CLOSING OFF
INTO THE PLAINS AND PCPN IN THE MS VALLEY. BY THE WEEKEND...THE
SYSTEM STARTS TO MOVE OUT...HOWEVER THE TIMING ON THIS WILL STILL
NEED TO BE WATCHED. TEMPS DUE TO CLOUDS AND SCT PCPN THROUGHOUT
END OF WEEK IS COOLER THEN THE BEGINNING OF THE WEEK. WENT WITH
CHC POPS AS DETAILS ON THE EXACT POSITION OF THE FRONT AND UPPER
SYSTEM STILL A LITTLE UNCERTAIN.

GOETSCH


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 405 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE THROUGH MONDAY...AS LOW
PRESSURE LIFTS NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO
VALLEY. THIS AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS
THE MID ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE
LINGERS OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE
REMAINS ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID- ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN OPEN
WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND AREA
INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED ALONG
AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN VLY.
CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND LOWER AS
EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS THE
PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW- LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA
PER FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS HAS HELD MAXIMA LARGELY IN THE
MID/UPPER 60S. EAST OF I-95...TEMPERATURES HV REACHED TO ~70/LOW
70S, AND HAVE EVEN DROPPED OFF SLIGHTLY AS CLDS HV BUILT EAST OVER
THE PAST FEW HRS.

RAIN CHANCES GRADUALLY INCREASE TONIGHT AS UPPER TROUGH
APPROACHES THROUGH LATE TONIGHT. INCREASING SYNOPTIC LIFT WILL
SHUNT A STEADY STREAM OF MOISTURE ADVECTION ACROSS THE AREA
TONIGHT, WHICH DEVELOPS ALONG THE EAST COAST. THIS INCREASE IN PW
IS THE RESULT OF THE APPROACHING TROUGH TO THE WEST AND
AFOREMENTIONED QUASI- STATIONARY HIGH TO THE EAST. THIS MOISTURE
TRANSPORT (GOOD MODEL AGREEMENT IN INCREASING PW VALUES TO ~1.3IN)
WILL OFFSET WEAKENING DYNAMICS AND YIELD A PERIOD OF LIGHT TO
MODERATE PCPN LATE TONIGHT INTO MONDAY MORNING. HAVE
CONTINUED/INCREASED POPS INTO CATEGORICAL RANGE WEST OF THE BAY
AFTER 00Z/8P EDT, WITH RAIN CHANCES INCREASING OVER THE EASTERN
SHORE AFTER 06Z/2AM MONDAY.

FOR LOWS, CLOUDY SKY AND MOISTENING LLVLS SHOULD KEEP HIGHS MILD.
EARLY MORNING LOWS IN THE MID 50S TO NR 60.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
BY MONDAY...THE TROUGH AXIS VERY SLOWLY APPROACHES THE WESTERN
PORTION OF THE AREA MONDAY MORNING. STEADY STRATIFORM RAIN TAPERS
TO SOME SHRAS WEST OF I-95 MONDAY AFTN AS THE BEST MOISTURE
TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST. 12Z GFS/NAM EACH
SHUNT OMEGA MAX FROM THE THE EASTERN CAROLINAS ACROSS ATLANTIC
COASTAL AREAS MONDAY AFTERNOON AND EVENING...WHICH MESHES WELL
WITH PROGGED AREA OF UPPER DIVERGENCE. THUS, WILL CONTINUE WITH
50-60 POP DURING THIS TIME FRAME AS RAIN CHCS TAPER TO SLIGHT CHC
WEST OF RIC. GIVEN BKN/OVC SKY COVER AND MEAGER INSTABILITY, HAVE
HELD THUNDER OUT OF THE FORECAST FOR NOW. GIVEN CONTINUED
CLOUDINESS, HIGHS REMAIN COOL FOR LATE APRIL...GENERALLY IN THE
UPR 60S TO NR 70, ALTHOUGH AGAIN LOCALLY COOLER ALONG IMMEDIATE
COASTLINES IN ONSHORE FLOW.

THE MID-LEVEL TROUGH AXIS PIVOTS OFF THE COAST LATE MONDAY NIGHT
AND TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK).
HIGH PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW
LINGERS OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO
PERSIST...WHICH SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT
CHANCE/LOW END CHANCE POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

TUESDAY/WEDNESDAY...
MID/UPPER LEVEL FLOW FLATTENS OUT/BECOMES QUASI-ZONAL ON TUESDAY.
THE RESULTANT MODEST DRYING ALOFT SHOULD RESULT IN A FAR DRIER DAY
ON TUESDAY. HOWEVER, STILL CANNOT TOTALLY REMOVE POPS WITH
LINGERING MOISTURE PRESENT IN LOW LEVELS PER MODEL CROSS SECTIONS.
THUS, WL RETAIN A 20-30 POP FOR SOME DIURNALLY DRIVEN SHRAS
TUESDAY AFTN/ERY EVE. FOR TEMPERATURES, FORECAST MAXIMA JUST A BIT
BELOW GUIDANCE GIVEN CONTINUED CLOUD COVER, WITH TEMPS INTO THE
LOW/MID 70S EXPECTED. EARLY MORNING LOWS GENERALLY IN THE MID TO
UPPER 50S.

DRIER ON WEDNESDAY COURTESY OF BUILDING MID-UPR RIDGING ALOFT
(COURTESY OF DEVELOPING UPPER TROUGH UPSTREAM ACROSS THE
INTERMOUNTAIN WEST). GIVEN CONTINUED MOIST LLVLS W/ONSHORE FLOW,
WL RETAIN A LOW POP FOR NOW. OTHERWISE, LOOK FOR HIGHS IN THE UPR
60S TO LOW 70S UNDER A PARTLY TO MOSTLY CLOUDY SKY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER FROM W TO E
TODAY. KRIC MAY SEE A SHOWER THROUGH 21Z BUT DO NOT EXPECT PCPN TO
REACH THE OTHER TAF SITES UNTIL AFTER SUNSET DUE TO LOW LEVEL DRY
AIR. THE SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF MVFR/IFR
CONDS AND WIDESPREAD RAIN BY LATE THIS EVENING THROUGH EARLY TUESDAY
WITH IMPROVING CONDS DURING THE DAY TUESDAY.

CONFIDENCE BEYOND TUESDAY IS LOW DUE TO FORECAST MODELS DEPICTING
THE POSSIBILITY FOR SHRA DEVELOPMENT. CURRENT FORECASTS HAVE
MAINLY VFR AND ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY DUE
TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWER DEVELOPMENT.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
THIS EVENING LEADING TO ONSHORE FLOW AROUND 10 KT. WAVES OVER THE
BAY GENERALLY 2 FT AND SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE
MOVES THRU THE OHIO VALLEY TONIGHT WITH SOUTHERLY WINDS INCREASING
TO 10-15 KT OVER THE WATERS. THE LOW WEAKENS AS IT APPROACHES THE
WATERS MONDAY. HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH
STRONG HIGH PRESSURE STILL OFFSHORE WILL ALLOW FOR 15-20 KT
SOUTHERLY WINDS OVER THE BAY AND 20-25 KT OVER THE COASTAL WATERS
WITH SEAS BUILDING TO 5-6 FT. SCA`S REMAIN IN PLACE FOR ALL THE
COASTAL WATERS BEGINNING 6-10 AM MONDAY AND CONTINUING THROUGH
MONDAY NIGHT AND HAVE BEEN RAISED FOR ALL BAY ZONES INCLUDING THE
CURRITUCK SOUND STARTING 7 AM THROUGH 7 PM. SMALL CRAFT CONDITIONS
WILL COME DOWN ON THE BAY/SOUND AS THE PRESSURE GRADIENT BEGINS TO
RELAX MON EVENING. SFC HIGH PRESSURE REMAINS LOCKED IN PLACE OVER
THE NEW ENGLAND COAST THRU THE COMING WEEK ALLOWING FOR PERSISTENT
E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH WINDS WILL LIKELY REMAIN
SUB-SCA DURING THIS TIME...SEAS WILL REMAIN AOA 5 FT SO SCA`S WILL
LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 7 PM EDT MONDAY FOR
     ANZ630>634.
     SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...MAS
AVIATION...JDM/DAP
MARINE...JDM/DAP







AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 357 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE THROUGH MONDAY...AS LOW
PRESSURE LIFTS NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO
VALLEY. THIS AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS
THE MID ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE
LINGERS OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE
REMAINS ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID-ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN
OPEN WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND
AREA INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED
ALONG AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN
VLY. CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND
LOWER AS EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW-LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA PER
FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS HAS HELD MAXIMA LARGELY IN THE
MID/UPPER 60S. EAST OF I-95...TEMPERATURES HV REACHED TO ~70/LOW
70S, AND HAVE EVEN DROPPED OFF SLIGHTLY AS CLDS HV BUILT EAST OVER
THE PAST FEW HRS.

RAIN CHANCES GRADUALLY INCREASE TONIGHT AS UPPER TROUGH
APPROACHES THROUGH LATE TONIGHT. INCREASING SYNOPTIC LIFT WILL
SHUNT A STEADY STREAM OF MOISTURE ADVECTION ACROSS THE AREA
TONIGHT, WHICH DEVELOPS ALONG THE EAST COAST. THIS INCREASE IN PW
IS THE RESULT OF THE APPROACHING TROUGH TO THE WEST AND
AFOREMENTIONED QUASI- STATIONARY HIGH TO THE EAST. THIS MOISTURE
TRANSPORT (GOOD MODEL AGREEMENT IN INCREASING PW VALUES TO ~1.3IN)
WILL OFFSET WEAKENING DYNAMICS AND YIELD A PERIOD OF LIGHT TO
MODERATE PCPN LATE TONIGHT INTO MONDAY MORNING. HAVE
CONTINUED/INCREASED POPS INTO CATEGORICAL RANGE WEST OF THE BAY
AFTER 00Z/8P EDT, WITH RAIN CHANCES INCREASING OVER THE EASTERN
SHORE AFTER 06Z/2AM MONDAY.

FOR LOWS, CLOUDY SKY AND MOISTENING LLVLS SHOULD KEEP HIGHS MILD.
EARLY MORNING LOWS IN THE MID 50S TO NR 60.


&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...

BY MONDAY...THE TROUGH AXIS VERY SLOWLY APPROACHES THE WESTERN
PORTION OF THE AREA MONDAY MORNING. STEADY STRATIFORM RAIN TAPERS
TO SOME SHRAS WEST OF I-95 MONDAY AFTN AS THE BEST MOISTURE
TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST. 12Z GFS/NAM EACH
SHUNT OMEGA MAX FROM THE THE EASTERN CAROLINAS ACROSS ATLANTIC
COASTAL AREAS MONDAY AFTERNOON AND EVENING...WHICH MESHES WELL
WITH PROGGED AREA OF UPPER DIVERGENCE. THUS, WILL CONTINUE WITH
50-60 POP DURING THIS TIME FRAME AS RAIN CHCS TAPER TO SLIGHT CHC
WEST OF RIC. GIVEN BKN/OVC SKY COVER AND MEAGER INSTABILITY, HAVE
HELD THUNDER OUT OF THE FORECAST FOR NOW. GIVEN CONTINUED
CLOUDINESS, HIGHS REMAIN COOL FOR LATE APRIL...GENERALLY IN THE
UPR 60S TO NR 70, ALTHOUGH AGAIN LOCALLY COOLER ALONG IMMEDIATE
COASTLINES IN ONSHORE FLOW.

THE MID-LEVEL TROUGH AXIS PIVOTS OFF THE COAST LATE MONDAY NIGHT
AND TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK).
HIGH PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW
LINGERS OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO
PERSIST...WHICH SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT
CHANCE/LOW END CHANCE POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

TUESDAY/WEDNESDAY...
MID/UPPER LEVEL FLOW FLATTENS OUT/BECOMES QUASI-ZONAL ON TUESDAY.
THE RESULTANT MODEST DRYING ALOFT SHOULD RESULT IN A FAR DRIER DAY
ON TUESDAY. HOWEVER, STILL CANNOT TOTALLY REMOVE POPS WITH
LINGERING MOISTURE PRESENT IN LOW LEVELS PER MODEL CROSS SECTIONS.
THUS, WL RETAIN A 20-30 POP FOR SOME DIURNALLY DRIVEN SHRAS
TUESDAY AFTN/ERY EVE. FOR TEMPERATURES, FORECAST MAXIMA JUST A BIT
BELOW GUIDANCE GIVEN CONTINUED CLOUD COVER, WITH TEMPS INTO THE
LOW/MID 70S EXPECTED. EARLY MORNING LOWS GENERALLY IN THE MID TO
UPPER 50S.

DRIER ON WEDNESDAY COURTESY OF BUILDING MID-UPR RIDGING ALOFT
(COURTESY OF DEVELOPING UPPER TROUGH UPSTREAM ACROSS THE
INTERMOUNTAIN WEST). GIVEN CONTINUED MOIST LLVLS W/ONSHORE FLOW,
WL RETAIN A LOW POP FOR NOW. OTHERWISE, LOOK FOR HIGHS IN THE UPR
60S TO LOW 70S UNDER A PARTLY TO MOSTLY CLOUDY SKY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER FROM W TO E
TODAY. KRIC MAY SEE A SHOWER THROUGH 21Z BUT DO NOT EXPECT PCPN TO
REACH THE OTHER TAF SITES UNTIL AFTER SUNSET DUE TO LOW LEVEL DRY
AIR. THE SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF MVFR/IFR
CONDS AND WIDESPREAD RAIN BY LATE THIS EVENING THROUGH EARLY TUESDAY
WITH IMPROVING CONDS DURING THE DAY TUESDAY.

CONFIDENCE BEYOND TUESDAY IS LOW DUE TO FORECAST MODELS DEPICTING
THE POSSIBILITY FOR SHRA DEVELOPMENT. CURRENT FORECASTS HAVE
MAINLY VFR AND ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY DUE
TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWER DEVELOPMENT.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
TODAY LEADING TO LIGHT ONSHORE FLOW. WAVES OVER THE BAY 1-2 FT AND
SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE MOVES THRU THE OHIO
VALLEY TONIGHT WITH SERLY WINDS INCREASING TO 10-15 KT OVER THE
WATERS. THE LOW WEAKENS AS IT APPROACHES THE WATERS MONDAY.
HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH STRONG HIGH PRESSURE
STILL OFFSHORE WILL ALLOW FOR 10-15 KT SERLY WINDS OVER THE BAY AND
15-20 KT OVER THE COASTAL WATERS WITH SEAS BUILDING TO 5-6 FT. HAVE
HOISTED SCA`S FOR ALL THE COASTAL WATERS BEGINNING 6-10 AM MONDAY
AND CONTINUING THROUGH MONDAY NIGHT. SFC HIGH PRESSURE REMAINS
LOCKED IN PLACE OVER THE NEW ENGLAND COAST THRU THE COMING WEEK
ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH
WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS WILL REMAIN
AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...MAS
AVIATION...JDM/DAP
MARINE...JDM










AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 158 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE...AS LOW PRESSURE LIFTS
NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO VALLEY. THIS
AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS THE MID
ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE LINGERS
OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE REMAINS
ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID-ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN
OPEN WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND
AREA INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED
ALONG AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN
VLY. CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND
LOWER AS EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW-LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA PER
FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS SHOULD HOLD MAXIMA IN THE MID/UPPER
60S WEST OF I-95 WHERE CLOUD COVER WILL BE MOST OPAQUE THIS AFTN.
EAST OF I-95...TEMPERATURES IN ~70/LOW 70S ARE EXPECTED.
HOWEVER...READINGS WILL BE LOCALLY COOLER ALONG THE IMMEDIATE
COASTLINES WITH ONSHORE FLOW.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE PRIMARY SHORTWAVE TROUGH LIFTS TOWARD THE GREAT LAKES TONIGHT
WITH THE TRAILING AXIS EXTENDING OVER THE APPALACHIANS. THE SURFACE
LOW GRADUALLY LOSES ITS DISTINCTION. BY MONDAY...THE TROUGH AXIS
VERY SLOWLY APPROACHES THE WESTERN PORTION OF THE AREA. A STEADY
STREAM OF MOISTURE ADVECTION DEVELOPS ALONG THE EAST COAST AS A
RESULT OF THE APPROACHING TROUGH TO THE WEST AND A QUASI-STATIONARY
HIGH TO THE EAST. THIS MOISTURE TRANSPORT (PW VALUES RISING TO
~1.3IN) OFFSETS WEAKENING DYNAMICS AND AS A RESULT POPS HAVE BEEN
INCREASED TO CATEGORICAL FOR ALL BUT THE EASTERN SHORE AFTER 06Z
MONDAY AND THEN INTO THE EASTERN SHORE MONDAY MORNING (AFTER 12Z).
THE BEST MOISTURE TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST DURING
THE AFTERNOON AND EVENING HOURS AND HENCE POPS WILL SLOWLY DIMINISH
FOR WESTERN AREAS. CONFIDENCE ON QPF REMAINS RATHER LOW AS IT WILL
ULTIMATELY BE DICTATED BY HOW MUCH SHORTWAVE DYNAMICS REMAIN. 00Z
GFS/NAM EACH INDICATE A MAX IN OMEGA OVER THE EASTERN CAROLINAS
MONDAY...WHICH HAS THE POTENTIAL TO LIMIT THE AMOUNT OF MOISTURE
TRANSPORTED INTO THE MID-ATLANTIC REGION.

THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST LATE MONDAY NIGHT AND
TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK). HIGH
PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW LINGERS
OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO PERSIST...WHICH
SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT CHANCE/LOW END CHANCE
POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY PERIODS OF UNSETTLED WX
AND NEAR NORMAL TEMPS. LO CONFIDENCE ON TIMING OF PRECIP DUE TO A
DEVELOPING BLOCKING PATTERN. DID FAVOR THE SLOWER GUIDANCE WRT
APPROACHING CUTOFF LO (ECMWF) AS MODELS TEND TO BREAK DOWN BLOCKING
PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO QUICKLY. OVERALL...HI
AMPLITUDE UPR-LVL RIDGE WILL PERSIST OVER THE FAR EASTERN CONUS
THRU THE LONG TERM PERIOD. MID-LVL VORT MAXIMA SWINGING AROUND AN
OFFSHORE CUTOFF LO AND ASSOCIATED MOISTURE SURGES WILL LEAD TO CHCS
FOR RAIN AT TIMES THRU THE PERIOD. KEPT POPS CAPPED AT 20-30% DUE TO
ISSUES WITH PRECIP TIMING AND THE ECMWF BEING SLOWER WITH THE CUTOFF
LO. HIGH TEMPS AVG IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR
40S/LWR 50S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER FROM W TO E
TODAY. KRIC MAY SEE A SHOWER THROUGH 21Z BUT DO NOT EXPECT PCPN TO
REACH THE OTHER TAF SITES UNTIL AFTER SUNSET DUE TO LOW LEVEL DRY
AIR. THE SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF MVFR/IFR
CONDS AND WIDESPREAD RAIN BY LATE THIS EVENING THROUGH EARLY TUESDAY
WITH IMPROVING CONDS DURING THE DAY TUESDAY.

CONFIDENCE BEYOND TUESDAY IS LOW DUE TO FORECAST MODELS DEPICTING
THE POSSIBILITY FOR SHRA DEVELOPMENT. CURRENT FORECASTS HAVE
MAINLY VFR AND ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY DUE
TO UNCERTAINTY IN TIMING AND LOCATION OF SHOWER DEVELOPMENT.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
TODAY LEADING TO LIGHT ONSHORE FLOW. WAVES OVER THE BAY 1-2 FT AND
SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE MOVES THRU THE OHIO
VALLEY TONIGHT WITH SERLY WINDS INCREASING TO 10-15 KT OVER THE
WATERS. THE LOW WEAKENS AS IT APPROACHES THE WATERS MONDAY.
HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH STRONG HIGH PRESSURE
STILL OFFSHORE WILL ALLOW FOR 10-15 KT SERLY WINDS OVER THE BAY AND
15-20 KT OVER THE COASTAL WATERS WITH SEAS BUILDING TO 5-6 FT. HAVE
HOISTED SCA`S FOR ALL THE COASTAL WATERS BEGINNING 6-10 AM MONDAY
AND CONTINUING THROUGH MONDAY NIGHT. SFC HIGH PRESSURE REMAINS
LOCKED IN PLACE OVER THE NEW ENGLAND COAST THRU THE COMING WEEK
ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH
WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS WILL REMAIN
AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/DAP
MARINE...JDM









AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 147 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE...AS LOW PRESSURE LIFTS
NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO VALLEY. THIS
AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS THE MID
ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE LINGERS
OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE REMAINS
ANCHORED OVER THE CANADIAN MARITIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID-ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN
OPEN WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND
AREA INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED
ALONG AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN
VLY. CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND
LOWER AS EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW-LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA PER
FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.

THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS SHOULD HOLD MAXIMA IN THE MID/UPPER
60S WEST OF I-95 WHERE CLOUD COVER WILL BE MOST OPAQUE THIS AFTN.
EAST OF I-95...TEMPERATURES IN ~70/LOW 70S ARE EXPECTED.
HOWEVER...READINGS WILL BE LOCALLY COOLER ALONG THE IMMEDIATE
COASTLINES WITH ONSHORE FLOW.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE PRIMARY SHORTWAVE TROUGH LIFTS TOWARD THE GREAT LAKES TONIGHT
WITH THE TRAILING AXIS EXTENDING OVER THE APPALACHIANS. THE SURFACE
LOW GRADUALLY LOSES ITS DISTINCTION. BY MONDAY...THE TROUGH AXIS
VERY SLOWLY APPROACHES THE WESTERN PORTION OF THE AREA. A STEADY
STREAM OF MOISTURE ADVECTION DEVELOPS ALONG THE EAST COAST AS A
RESULT OF THE APPROACHING TROUGH TO THE WEST AND A QUASI-STATIONARY
HIGH TO THE EAST. THIS MOISTURE TRANSPORT (PW VALUES RISING TO
~1.3IN) OFFSETS WEAKENING DYNAMICS AND AS A RESULT POPS HAVE BEEN
INCREASED TO CATEGORICAL FOR ALL BUT THE EASTERN SHORE AFTER 06Z
MONDAY AND THEN INTO THE EASTERN SHORE MONDAY MORNING (AFTER 12Z).
THE BEST MOISTURE TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST DURING
THE AFTERNOON AND EVENING HOURS AND HENCE POPS WILL SLOWLY DIMINISH
FOR WESTERN AREAS. CONFIDENCE ON QPF REMAINS RATHER LOW AS IT WILL
ULTIMATELY BE DICTATED BY HOW MUCH SHORTWAVE DYNAMICS REMAIN. 00Z
GFS/NAM EACH INDICATE A MAX IN OMEGA OVER THE EASTERN CAROLINAS
MONDAY...WHICH HAS THE POTENTIAL TO LIMIT THE AMOUNT OF MOISTURE
TRANSPORTED INTO THE MID-ATLANTIC REGION.

THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST LATE MONDAY NIGHT AND
TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK). HIGH
PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW LINGERS
OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO PERSIST...WHICH
SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT CHANCE/LOW END CHANCE
POPS DURING THIS TIME PERIOD.

HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY PERIODS OF UNSETTLED WX
AND NEAR NORMAL TEMPS. LO CONFIDENCE ON TIMING OF PRECIP DUE TO A
DEVELOPING BLOCKING PATTERN. DID FAVOR THE SLOWER GUIDANCE WRT
APPROACHING CUTOFF LO (ECMWF) AS MODELS TEND TO BREAK DOWN BLOCKING
PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO QUICKLY. OVERALL...HI
AMPLITUDE UPR-LVL RIDGE WILL PERSIST OVER THE FAR EASTERN CONUS
THRU THE LONG TERM PERIOD. MID-LVL VORT MAXIMA SWINGING AROUND AN
OFFSHORE CUTOFF LO AND ASSOCIATED MOISTURE SURGES WILL LEAD TO CHCS
FOR RAIN AT TIMES THRU THE PERIOD. KEPT POPS CAPPED AT 20-30% DUE TO
ISSUES WITH PRECIP TIMING AND THE ECMWF BEING SLOWER WITH THE CUTOFF
LO. HIGH TEMPS AVG IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR
40S/LWR 50S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR CONDS ARE EXPECTED THROUGH AT LEAST 00Z MONDAY. MID-LEVEL
CLOUDS WILL THICKEN AND LOWER FROM W TO E TODAY AND PCPN IS NOT
LIKELY TO REACH THE TAF SITES UNTIL AFTER SUNSET.

OUTLOOK...A SLOW MOVING SYSTEM WILL BRING AN INCREASING CHC OF
MVFR/IFR CONDS IN RAIN BY LATE THIS EVENING THROUGH EARLY
TUESDAY. CONDS BEGIN TO IMPROVE DURING THE DAY TUESDAY. CONFIDENCE
BEYOND TUESDAY IS LOW BUT CURRENT FORECASTS HAVE MAINLY VFR AND
ONLY SLGT CHC FOR PCPN WEDNESDAY AND THURSDAY.

&&

.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
TODAY LEADING TO LIGHT ONSHORE FLOW. WAVES OVER THE BAY 1-2 FT AND
SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE MOVES THRU THE OHIO
VALLEY TONIGHT WITH SERLY WINDS INCREASING TO 10-15 KT OVER THE
WATERS. THE LOW WEAKENS AS IT APPROACHES THE WATERS MONDAY.
HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH STRONG HIGH PRESSURE
STILL OFFSHORE WILL ALLOW FOR 10-15 KT SERLY WINDS OVER THE BAY AND
15-20 KT OVER THE COASTAL WATERS WITH SEAS BUILDING TO 5-6 FT. HAVE
HOISTED SCA`S FOR ALL THE COASTAL WATERS BEGINNING 6-10 AM MONDAY
AND CONTINUING THROUGH MONDAY NIGHT. SFC HIGH PRESSURE REMAINS
LOCKED IN PLACE OVER THE NEW ENGLAND COAST THRU THE COMING WEEK
ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH
WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS WILL REMAIN
AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
     ANZ656-658.

&&

$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM
MARINE...JDM
EQUIPMENT...










AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 116 PM EDT SUN APR 28 2013


.AVIATION...

//DISCUSSION...

MOISTURE AND RAIN SHOWERS CONTINUE TO SURGE NORTH ACROSS SOUTHEAST
MICHIGAN EARLY THIS AFTERNOON. HOWEVER WITH THE MAIN SURFACE LOW
TRACKING EAST THE MAIN AREA OF PRECIPITATION IS EXPECTED TO MAKE A
PIVOT FROM MOVING NORTH TO EXITING EAST ALONG WITH THE SURFACE LOW.
THEREFORE LITTLE IF ANY RAIN IS EXPECTED TO FALL AT MBS. HOWEVER LOW
LEVEL MOISTURE IS STILL EXPECTED TO PUSH INTO MBS...BRINGING
CONDITIONS DOWN TO IFR LIKE THE REST OF THE TAF SITES. HOWEVER WITH
LESS RAIN MBS IS EXPECTED TO BE BETTER OFF THAN THE REST OF THE TAF
SITES FURTHER SOUTH WHICH ARE EXPECTED TO DROP TO LIFR AND VLIFR
OVERNIGHT AS FRESH MOISTURE ON THE GROUND BRINGS STRATUS AND POCKETS
OF FOG DURING THE OVERNIGHT HOURS.

FOR DTW...THE STEADY SHOWER ACTIVITY IS EXPECTED TO END AROUND 00Z.
ABUNDANT LOW LEVEL MOISTURE WILL BRING A MEDIUM TO HIGH POTENTIAL
FOR VLIFR CONDITIONS THROUGHOUT TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH TONIGHT.

* MEDIUM TO HIGH CONFIDENCE IN CEILINGS DOWN TO 200 FEET AFTER 00Z.

&&

.PREV DISCUSSION...ISSUED 1056 AM EDT SUN APR 28 2013

UPDATE...

RAIN SHOWERS CONTINUE TO EDGE NORTHWARD INTO SOUTHEASTERN MICHIGAN
DURING THE LATE MORNING HOURS. HOWEVER THEY ARE ENCOUNTERING QUITE
A BIT OF LOW LEVEL DRY AIR AS EVIDENCED BY THE 12Z DTX RAOB
SOUNDING. THE LOCAL HI-RES MODELS ARE CAPTURING THIS QUITE WELL
AND KEEP MUCH OF THE ACTIVITY ALONG AND SOUTH OF M-59 THROUGH THE
EARLY AFTERNOON...THEN TRANSITIONING OFF TO THE EAST AS THE LOW
TRACKS EAST THROUGH OHIO. GIVEN THE ABUNDANT DRY AIR IN PLACE
ACROSS THE NORTH AND THE PERFORMANCE OF THE LOCAL 3KM HRRR MODEL
WILL TIGHTEN UP THE POPS ACROSS THE CWA...LOWERING AMOUNTS ACROSS
THE NORTH AND RAISING THEM ACROSS THE SOUTH.

PREV DISCUSSION...ISSUED 356 AM EDT SUN APR 28 2013

SHORT TERM...TODAY AND TONIGHT

08-12Z...AN AMPLITUDE INCREASE OF THE EASTERN NORTH AMERICA LONGWAVE
RIDGE WILL BE THE FORCING MECHANISM WHICH WILL DRAW THE SOUTHERN IL
PV ANOMALY NORTHWARD INTO MICHIGAN TODAY. TWO SPIRALS OF 700-500MB
DEFORMATION WILL EMANATE NORTHWARD AWAY FROM THE PARENT VORTICITY
MAXIMUM THE FIRST OF WHICH WILL LIFT ACROSS THE MICHIGAN/OHIO
STATELINE AFTER 9Z. THIS IS ADVERTISED BY LINEAR EXTRAPOLATION FROM
RADAR MOSAIC AND TIMING OF NAM/RAP. DEFORMATION FORCING WILL BE
COASTING INTO THE STATE...WEAKENING DRAMATICALLY ACCORDING TO NWP
PROJECTIONS. FEEL GOOD ABOUT THIS GIVEN INCREASING DISTANCE FROM
VORTICITY MAXIMUM...WARMING CLOUD TOPS IN LATEST IR...AND SPOTTY
COVERAGE IN AREA RADAR IMAGERY. WHAT THE INBOUND AIRMASS WILL HAVE
IS GOOD MOISTURE QUALITY...SATURATION UPWARDS OF 30 KFT AND PWATS
THAT SPIKE OVER 1.0 INCH BY 12Z. GIVEN THE LESS THAN SPECTACULAR
FORCING...EXPECT A SOLID NUMEROUS/SCT COVERAGE OF LIGHT SHOWERS THIS
MORNING WITHIN THE ARC.

PRECIPITATION MAY REACH DTW BY 12Z.

12-19Z...NAM AND RAP SOLUTIONS DIVERGE AT THIS POINT ON TWO MAIN
POINTS...1. TIMING OF LEAD 700-500 DEFORMATION SURGE AND 2.
PRECIPITATION POTENTIAL WITHIN THIS ARC DURING THIS TIMEFRAME. RAP
IS FASTER/BULLISH ON PRECIPITATION WHILE THE NAM LAGS CONSIDERABLY.
GFS IS A COMPROMISE WITH FASTER TIMING...BUT MUCH LESS ON THE QPF.
TYPICALLY WOULD FAVOR THE BULLISH QPF AMOUNTS GIVEN OUTSTANDING
COLUMN SATURATION...BUT LACK OF DYNAMICS LEAVES ONE UNEASY. THE
DECIDING FACTOR HERE WILL BE OVERALL LACK OF LAPSE RATES AND
INSTABILITY AND FOR THAT REASON WILL SHAPE THE FORECAST WITH LOWER
QPF AMOUNTS IN LIGHTER SHOWER ACTIVITY...AN AVERAGED .05 THROUGH THE
M 59 CORRIDOR.

LIGHT SHOWER ACTIVITY MAY REACH PTK BY...1330Z.
                                FNT BY...1430Z.
     STALLING OUT JUST SOUTH OF MBS BY...16Z.

19-00Z...BAROCLINICITY IS LOW BUT NON-EXISTENT WITH THIS SYSTEM. IN
FACT...NAM IS SUGGESTING THAT A FRESH 850MB THETA E PLUME WILL
ADVECT STRAIGHT NORTHWARD...PUSHING INTO MUCH OF SOUTHEASTERN
MICHIGAN AFTER 18Z. GFS/NAM BOTH IN AGREEMENT THE CENTER OF 500MB
VORTICITY WILL LIFT ALONG THE WESTERN EDGE OF THIS THETA E GRADIENT
INTO FAR SOUTHEASTERN LOWER MICHIGAN BETWEEN 21-00Z. INTEGRITY OF
WARM FRONTAL FORCING AND THERMAL GRADIENTS ARE NOT IDEAL BUT MASS
ADJUSTMENTS ALONG IMMEDIATE NORTHWEST FLANK OF VORT MAX SHOULD CARVE
OUT A RESPONSE. NAM IS ON POINT WITH 850-500MB DEFORMATION
ORGANIZATION WHICH REPRESENTS THE SECOND SPIRAL DISCUSSED EARLIER.
THE BEST FORCING IS EXPECTED TO OCCUR ACROSS THE FAR EASTERN CWA
FROM MONROE UP THROUGH ST CLAIR COUNTIES. THIS FORCING MAY RESULT IN
A SOLID .2 INCHES OF QPF. ACCOUNTED FOR THIS WITH CATEGORICAL POPS
IN THOSE AREAS. ELEVATED THUNDER CHANCES APPEAR MINIMAL AND
RELEGATED TO EXTREME SOUTHEASTERN CWA BETWEEN 19-00Z...NEGATIVE
SHOWALTER INDICES HERE IN SEMICH ARE ALL POSITIVE...LOWERED THE
CHANCES ACROSS THE BOARD.

00-12Z...LIGHT SHOWERS AND/OR DRIZZLE MAY PERSIST ACROSS EXTREME
EASTERN AREAS/ST CLAIR COUNTY THROUGH 3-6Z TONIGHT WITH DEFORMATION
AXIS EVENTUALLY PEELING EASTWARD. FLOW TRAJECTORY MAY KEEP SHOWERS
JUST EAST OF THE CWA OVER PORTIONS OF CANADA THROUGH THE REMAINDER
OF THE NIGHT. EXPECT A GRUNGY AIRMASS TONIGHT WITH CLOUDS AND
POSSIBLY SOME FOG. NIL TEMPERATURE ADVECTION TONIGHT...SUPPORTS A
HIGH CONFIDENCE MIN T FORECAST RIGHT AROUND 50 DEGREES.

LONG TERM... MONDAY THROUGH SATURDAY

TODAY`S WAVE WILL DEPART TO THE EAST BY MONDAY MORNING AND LEAVE SE
MICHIGAN BETWEEN IT AND A COLD FRONT MOVING SLOWLY THROUGH THE
WESTERN GREAT LAKES. THE PARENT SURFACE LOW IS SHOWN IN THE MODEL
SOLUTIONS TO BE OVER THE FAR NORTHERN REACHES OF HUDSON BAY LEAVING
THE FRONT TO STALL AND WEAKEN OVER NORTHERN LOWER MICHIGAN. WE WILL
ALSO BE COUNTING ON BROAD SURFACE LOW PRESSURE DEVELOPMENT OVER THE
PLAINS TO HELP WASH OUT THE FRONT WITH INCREASING LARGE SCALE
GRADIENT FLOW OVER THE GREAT LAKES. THIS LOOKS LIKE A GOOD BET DUE
TO STRONG UPPER LEVEL HEIGHT FALLS OVER THE ROCKIES INITIATED BY A
POWERFUL JET MOVING INLAND FROM THE PACIFIC NORTHWEST. SATELLITE
IMAGERY THIS MORNING SHOWS THIS JET STRUCTURE NICELY WHICH THE
MODELS THEN RAMP UP TO ABOUT 150 KNOTS BY 12Z MONDAY AS IT DIGS INTO
THE ROCKIES. THESE DEVELOPMENTS IN THE LARGE SCALE PATTERN WILL PUT
A STOP TO THE EASTWARD ADVANCEMENT OF THE FRONT IN THE GREAT LAKES
AND EVENTUALLY LEAD TO ITS DECAY. EXPECT THAT ALL BUT POSSIBLY THE
TRI CITIES WILL REMAIN DRY AS A RESULT BEFORE A SLUG OF GULF
MOISTURE IS INDICATED MOVING IN MONDAY NIGHT. DEPICTIONS OF LOW TO
MID LEVEL THETA-E FIELDS SHOW THIS MOISTURE PATTERN TO BE A FRAGMENT
OF A BETTER ORGANIZED MOISTURE AXIS TAKING SHAPE OVER THE PLAINS.
GIVEN THE LIMITED PREDICTABILITY, IT IS BEST TO HOLD OFF ON ANY
EXPANSION OF POPS OUTSIDE OF THE TRI CITIES AND NORTHERN THUMB THAT
COULD CONTINUE TO BE AFFECTED BY MOISTURE REMNANTS FROM THE COLD
FRONT.

MODEL SOLUTIONS CONTINUE TO LOOK REASONABLE THROUGH TUESDAY WITH
SOUTHWEST FLOW INCREASING WHICH, ALONG WITH THE BUILDING UPPER RIDGE
OVER THE OHIO VALLEY, WILL CARRY TEMPERATURES WELL INTO THE 70S
DURING THE AFTERNOON. THERE ARE MIXED SIGNALS IN THE MOISTURE FIELDS
AMONGST THE NAM, GFS, AND ECMWF BUT ONLY WITH REGARD TO CLOUD COVER
RATHER THAN RAIN CHANCES. EVEN IF THERE IS SOME MID CLOUD LEFT TO
SCOUR OUT DURING THE DAY, EXPECT ENOUGH SURFACE HEATING TO REACH
GUIDANCE HIGHS IN THE UPPER 70S WITH 80 EVEN BEING A REASONABLE
UPPER END OF THE RANGE OVER THE INTERIOR OF LOWER MICHIGAN
SUFFICIENTLY INLAND FROM THE SHORELINES. MODEL SOUNDINGS INDICATE A
TYPICALLY MIXED BOUNDARY LAYER UP TO ABOUT 850 MB WHERE TEMPERATURE
IN THE 12 TO 14C RANGE WILL BE FAVORABLE FOR THE WARMING TREND.

IT WAS TEMPTING TO GO MORE BULLISH ON MAX TEMPS WEDNESDAY AS WELL,
BUT EVIDENCE OF BACKING SURFACE WIND SUGGESTS CAUTION. MODEL
DEPICTIONS OF THE UPPER TROUGH DIGGING TOWARD THE 4 CORNERS REGION
LOOK SOLID DURING THAT TIME PERIOD. THIS WILL SET UP AN EXTREMELY
SHARP BAROCLINIC ZONE FROM THE SOUTHERN HIGH PLAINS INTO UPPER
MICHIGAN. WHILE THE FRONT WILL REMAIN TO OUR WEST, A GREATER
EASTERLY SURFACE WIND COMPONENT WILL BRING LAKE AGGREGATE COOLING
FARTHER INLAND COMPARED TO TUESDAY. THIS WILL KEEP MAX TEMPS IN THE
70S FOR ALL BUT THE VERY INTERIOR SECTIONS OF LOWER MICHIGAN AND
EVEN IN THE 60S NEAR THE SHORELINES.

FOR THE END OF THE WEEK, THE GFS HAS MADE A CONSIDERABLE WESTWARD
ADJUSTMENT ON ITS SOLUTION FOR THE POSITION OF THE CLOSED LOW
THURSDAY INTO FRIDAY JOINING THE ECMWF AND CANADIAN IN A GENERAL
CLUSTER OF SOLUTIONS OVER THE CENTRAL PLAINS. THIS ADDS SOME
CONFIDENCE TO THE IDEA THAT SE MICHIGAN WEATHER WILL BE INFLUENCED
MORE BY THE UPPER LEVEL RIDGE PORTION OF THE DEVELOPING OMEGA
BLOCK OVER THE EASTERN HALF OF THE COUNTRY.

MARINE...

GENTLE TO MODERATE SOUTHEAST FLOW AND SIGNIFICANT WAVE HEIGHTS
AVERAGING 2 FEET OR LESS WILL PERSIST THROUGH MONDAY NIGHT BEFORE
SOUTHERLY FLOW RAMPS UP IN ADVANCE OF AN APPROACHING COLD FRONT. AN
ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVER LAKE SAINT CLAIR
AND THE MICHIGAN WATERS OF LAKE ERIE AS SHOWERS SPREAD ACROSS THE
WATERS ON SUNDAY WITH MORE WIDESPREAD THUNDER POSSIBLE BY MIDWEEK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...CB
LONG TERM....BT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 107 PM EDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN APR 28 2013

WV IMAGERY AND RUC ANALYSIS INDICATED ZONAL FLOW FROM THE PACIFIC NW
TO THE NRN GREAT LAKES. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW
WAS MOVING THROUGH ERN SASK INTO MANITOBA WITH A TROUGH EXTENDING TO
THE CNTRL DAKOTAS. AHEAD OF THE TROUGH...SSW FLOW WAS INCREASING
OVER THE UPPER MS VALLEY AND NRN GREAT LAKES. WITH THE DRY AIRMASS
BELOW 700 MB...PER 00Z INL SOUNDING...WAA AHEAD OF THE TROUGH WAS
BRINGING MAINLY MID CLOUDS AND SOME VIRGA OR SPRINKLES INTO NRN MN.
ALTHOUGH DEWPOINTS HAD CLIMBED INTO THE MID 40S SRN AND CNTRL
MN...CIRCULATION AROUND THE LOW PRESSURE SYSTEM OVER SRN IL HAD
PREVENTED MORE ABUNDANT GULF MOISTURE FROM MOVING INTO THE REGION.

EXPECT THAT SUNSHINE AND MIXING TO 850-800 MB (850 MB TEMPS FROM 7C
TO 9C) WILL REULS IN MAX READINGS IN THE MID AND UPPER 60S EAST AND
LOWER 70S WEST. SRLY FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS
CLOSER TO 50.

AS THE SASKATCHEWAN LOW MOVES TO HUDSON BAY...IT WILL DRAG A COLD
FRONT INTO THE NRN GREAT LAKES TONIGHT. LOW LEVEL CONV NEAR THE
FRONT COMBINED WITH A WEAK SHORTWAVE MOVING OUT OF THE NRN PLAINS
WILL BE ENOUGH TO SUPPORT A BAND OF SHOWERS INTO UPPER MICHIGAN. THE
MODELS WERE IN GOOD AGREEMENT WITH THE FRONT AND PCPN BAND TRENDING
SLIGHTLY SLOWER. THE PCPN IS EXPECTED TO MOVE INTO THE WEST THIS
EVENING AND OVER THE CNTRL AND EAST OVERNIGHT. WITH ONLY WEAK
MID/UPPER LEVEL FORCING AND LIMITED MOISTURE INFLOW...OVERALL PCPN
AMOUNTS WILL BE LIGHT GENERALLY AOB 0.25 INCH...PER SREF PROB AND
CONSENSUS QPF. MDLS SUGGEST THAT ANY INSTABILITY TO SUPPORT TSRA WILL
REMAIN MAINLY TO THE S OF THE CWA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN APR 28 2013

BEST CONFIDENCE INTO WEDNESDAY...WITH MUCH REDUCED FORECAST
CONFIDENCE AFTER THAT. PUT PRIMARY EFFORTS/TIME INTO SHORTER TERM
GRIDS GIVEN FLOODING PROBLEMS THAT WILL BE MORE CONFINED TO SHORTER
TERM.

FOR MON...EXPECT A WEAK SFC TROUGH/COLD FRONT TO PUSH
THROUGH...KEEPING SFC TEMPS A LITTLE COOLER THAN YESTERDAY OR TODAY.
UP TO AROUND A QUARTER INCH OF QPF IS EXPECTED MON...BUT AT THE SAME
TIME MELTING OF THE SNOW PACK IS REDUCED BY EXTRA CLOUD COVER AND
COOLER TEMPS /ESPECIALLY NEAR LAKE SUPERIOR/...SO THESE TWO FACTORS
MAY CANCEL EACH OTHER OUT...STILL RESULTING IN A DECENT MELT
DAY...BUT THIS IS DIFFICULT TO DETERMINE.

TEMPORARY COOL DOWN MON COMES TO YET ANOTHER END WITH 60S AND 70
HIGH TEMPS OVER MUCH OF THE AREA TUE AS 850MB TEMPS INCREASE TO
AROUND 14C BY 18Z TUE. THESE WARMER TEMPS COME AHEAD OF ANOTHER
SYSTEM THAT WILL MOVE N OF LAKE SUPERIOR...WHICH BRINGS A COLD FRONT
ACROSS THE CWA LATE TUE INTO TUE NIGHT. MODELS ARE EVEN SHOWING
SOME CAPE ALONG AND AHEAD OF THE COLD FRONT...WHICH MAY RESULT IN
THUNDERSTORM ACTIVITY. THE HEAVIEST RAINFALL IS MAINLY FOCUSED OVER
THE ERN HALF OFF UPPER MI...AND WILL BE SOMETHING TO WATCH WITH
RESPECT TO CONTINUED FLOOD THREAT.

OTHER THAN THOSE SYSTEM...MODELS IN THE FARTHER EXTENDED SHOW LARGE
DISAGREEMENT IN THERMAL FIELDS...SO A WIDE VARIETY OF TEMPS ARE
POSSIBLE. ALTHOUGH MODELS DO SHOW GOOD GENERAL AGREEMENT...THE EXACT
PLACEMENT OF THE UPPER LOW THEY SHOW OVER THE CENTRAL CONUS BY FRI
IS ESSENTIAL FOR TEMPS/PRECIP. WILL JUST USE A CONSENSUS OF MODELS
FOR THIS PERIOD GIVEN THE UNCERTAINTY.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 107 PM EDT SUN APR 28 2013

EXPECT VFR CONDITIONS TO PREVAIL THROUGH THIS EVENING WITH THE
RELATIVELY DRY AIRMASS DOMINATING IN SW FLOW AROUND HIGH PRESSURE
OVER NEW ENGLAND. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 02Z AHEAD OF
AN INCOMING COLD FRONT...BUT LIMITED MSTR RETURN WL LIMIT PCPN
INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN VFR. AFTER
06Z...EXPECT ENOUGH LOW LEVEL MOISTENING FOR MVFR CONDITIONS TO
DEVELOP AT ALL TAF SITES. SOME IMPROVEMENT IS EXPECTED WITH DRIER
AIR COMING IN MON MORNING AT ALL SITES. CONDITIONS WILL GO BACK TO
VFR AT IWD AND SAW WITH HIGHER MVFR CIGS AT CMX.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN APR 28 2013

WINDS SHOULD STAY BELOW 25KTS THROUGH THE PERIOD WITH NO GALES IN
SIGHT. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&

.HYDROLOGY...
ISSUED AT 503 AM EDT SUN APR 28 2013

SAW GOOD MELTING YESTERDAY AFTERNOON WITH HIGH TEMPS IN THE 60S AND
70S AFTER THE SNOW PACK WARMED UP FROM SUB-FREEZING TEMPS THE NIGHT
BEFORE. SINCE TEMPS ARE WELL ABOVE FREEZING TONIGHT...AND HIGH TEMPS
TODAY WILL BE SIMILAR TO YESTERDAY BUT WITH SLIGHTLY HIGHER DEW
POINTS...WE SHOULD SEE EVEN BETTER MELTING FOR A LONGER PERIOD OF
TIME THAN YESTERDAY. PLACES WITH SNOWPACK REMAINING WILL SEE RAPID
AND EXTENSIVE MELTING TODAY...CAUSING RUNOFF INTO TONIGHT INTO AREA
STREAMS. RIVERS OF PARTICULAR CONCERN AFTER THE MELTING TODAY WILL
BE THE TRAP ROCK RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON
COUNTIES...AND THE PESHEKEE RIVER. RUNOFF MAY NOT PEAK UNTIL
TONIGHT/MONDAY...AND EVEN GET FORTIFIED BY ADDITIONAL MELTING AND
EVEN SOME RAIN ON MONDAY. RAINFALL AMOUNTS WILL GENERALLY BE AROUND
A QUARTER OF AN INCH...OR POSSIBLY MORE IN A FEW AREAS AND WILL
START LATE THIS EVENING INTO MONDAY. ANY RAIN WILL ONLY ADD TO
HYDROLOGIC CONCERNS...AND WILL HAVE TO PAY CLOSE ATTENTION TO PRECIP
AMOUNTS MONDAY. FURTHER CHANCES OF PRECIPITATION ARE EXPECTED AS
COLD FRONT WORKS THROUGH ON TUESDAY...WHEN THERE MAY BE
THUNDERSTORMS TOO. OTHERWISE...ADDITIONAL CHANCES OF PRECIPITATION
ARE POSSIBLE THE REST OF THE WEEK AS FRONT STAYS CLOSE BY TO THE
AREA.

MELTING SCENARIOS REMAIN THE BIGGEST CONFIDENCE REDUCERS AT THIS
POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE MELT
FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS WILL
LIKELY END UP QUITE A BIT HIGHER. ONCE PLACE WHERE THE MELT
CORRECTION FACTOR WAS INCREASED FOR FOR THE MEN RIVER FORECAST GROUP
/RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH RESULTED IN
MUCH INCREASED FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND
MODERATE FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR
REPUBLIC/WITCH LAKE. WFO SURVEY OF THE PESHEKEE RIVER REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS COULD CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES LATE TODAY INTO MONDAY. OF
COURSE...MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS WE ARE ALSO
LOOKING AT THREAT OF AREAL FLOOD PROBLEMS WITH SMALLER
CREEKS/STREAMS AND STANDING WATER ON ROADS. FOR FURTHER
DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE LATEST RIVER
WATCHES /FFAMQT/.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
HYDROLOGY...TITUS







AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

 1249 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 1235 PM CDT SUN APR 28 2013
MADE A FEW CHANGES TO THE REST OF THE DAY...MAINLY TO KEEP CLOUDS
HANGING IN LONGER AND TO LOWER TEMPERATURES A FEW DEGREES. THE
WESTERN EDGE OF THE CLOUDS BLEW UP WITH DIURNAL STRATO-CU
DEVELOPMENT A COUPLE OF HOURS AGO...AND IT SIMPLY HASN`T BEEN
MOVING AS FAST AS EARLIER ANTICIPATED. CURRENT THINKING IS THAT
THE VERY SLOW EASTWARD PROGRESSION WILL CONTINUE TODAY...AND THEN
THE DIURNAL CLOUDS WILL DISSIPATE PRETTY RAPIDLY AFTER 00Z.

CARNEY

&&

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 315 AM CDT SUN APR 28 2013

AREAS OF DRIZZLE AND ISO-SCT RAIN SHOWERS SHOULD FINALLY END TODAY
AS A SLOW-MOVING LOW PRESSURE SYSTEM CONTINUES MOVING AWAY FROM THE
AREA. RAP BUFKIT PROFILES SHOW MIXING TO AROUND H9 THEREFORE HIGHS
IN THE LOW/MID 60S TO AROUND 70 LOOK REASONABLE CONSIDERING INITIAL
CLOUD COVER AND MOIST LOW LEVELS FM RECENT RAINFALL. TEMPERATURES
WILL BE WARMER IN CENTRAL MO THAN IN SWRN IL BECAUSE OF QUICKER
CLEARING IN THE WESTERN CWA.

KANOFSKY

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 28 2013

(TONIGHT - WEDNESDAY)

UPPER LEVEL RIDGE WILL BUILD OVER ERN NOAM EARLY IN THE PERIOD AND
THEN PROCEED TO DOMINATE THRU THE MIDDLE OF THE WEEK...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE HI PLAINS BY WEDNESDAY.
THIS SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.

THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY AND TUESDAY
MAX TEMPS...BUT IN SEVERAL LOCALES...WENT A COUPLE DEGS HIGHER TO
SUPPORT H900-850 TEMPS ALOFT DEPICTED BY THE MODELS AND ANTICIPATED
SUNSHINE.  LOOK FOR UPR 70S-LO 80S ON MONDAY WITH MID 80S TUESDAY
WITH A MORE SW WIND EXPECTED.  AN OUTSIDE CHANCE AT UPR 80S WILL
PRESENT ITSELF FOR PARTS OF STL METRO TUESDAY.  LOSS OF W COMPONENT
TO SFC WND ON WEDNESDAY AND SOME UNCERTAINTY ON WHERE FRONT WILL
BE...HAVE 80-85F FCSTD FOR MOST SPOTS.

TWO SMALL WINDOWS OF OPPORTUNITY FOR RAIN THIS PERIOD.  THE FIRST IS
ON MONDAY AFTERNOON-NIGHT.  MODELS ALL SHOW PRETTY STOUT INSTABILITY
AND 0-6KM BULK SHEAR OF 30-35KTS IN PLACE AHEAD OF WHAT SHOULD BE A
CDFNT EDGING INTO THE NWRN FA BY LATE MONDAY AFTERNOON BEFORE IT
STALLS AND WASHES OUT MONDAY NIGHT.  HOWEVER...SOME OF THESE LARGE
INSTABILITY VALUES ARE PREDICATED ON WHAT LOOKS TO BE A TOO
AGGRESSIVE LO LEVEL MOISTURE RETURN...AND A DEPENDENCE IN PART ON
SFC DWPTS REACHING INTO THE MID-UPR 60S.  HOWEVER...LO LEVEL MASS
FIELDS DO NOT SUPPORT A LO LEVEL MOISTURE RETURN OF THAT MAGNITUDE
WITH WEAK FLOW AND A WEAK BLOCKING RIDGE NEAR THE GULF OF MEXICO
UNTIL MONDAY AFTERNOON AND THEN IT SHOULD BE TOO SMALL A TIME PERIOD
TO GET THE RICH MOISTURE THAT FAR N.  SFC DWPTS INSTEAD EDGING NEAR
60F LOOK MORE LIKELY BUT THIS WILL STILL YIELD CINH VALUES AT OR
ABOVE 20 J/KG WHICH WILL PROBABLY BE ALL IT WILL NEED TO BLOCK MOST
CONVECTION WITH A WEAKENING SFC FRONT.  BUFR SOUNDINGS BASED ON OUR
LOCAL WRF DEPICT THIS WELL.  SO...IF SOMETHING CAN POP...IT SHOULD
SUPPORT DAY SHIFT YESTERDAY/S ASSERTION WITH DECENT CHANCE OF IT
GOING TO SEVERE...BUT OCCURRENCE OF ANY CONVECTION LOOKS TO BE
PRETTY LIMITED.  AFTER SUNSET MONDAY EVENING...CINH RAPIDLY
INCREASES WITH THE SFC FRONT STARTING TO WASH OUT...AND SO WINDOW
FOR CONVECTION WILL RAPIDLY CLOSE.  MADE MINIMAL CHANGES TO PREVIOUS
FCST WHICH ALREADY HAD MINIMAL CHC POPS LIMITED TO THE NW FA.

STILL SOME MODEL DIFFS ON TIMING OF THE SFC CDFNT FOR MID-LATE
WEEK...WITH THE GFS CONTINUING TO BE THE FASTEST INTO OUR AREA BY
WEDNESDAY AFTERNOON WITH THE ECMWF SOME 12HRS LATER INTO EARLY
THURSDAY MORNING.  BACKED OFF SOME ON POPS FOR WEDNESDAY WITH THE
ECMWF CONTINUING TO LEAD THE GFS TO WHAT HOPEFULLY WILL BE THE
VERIFYING SOLN...WHICH HAS STEADILY BEEN FAVORING A SLOWER FROPA.

(THURSDAY - SATURDAY)

LOOKING INCREASINGLY LIKE A COOL AND WET PERIOD.

THE LARGE DISCREPANCY ON WHEN AND WHERE TO FORM THE CUTOFF LO HAS
BEEN OVERCOME FOR THE MOST PART WITH THE GFS FOLLOWING THE ECMWF/S
LEAD FOR A MORE RAPID FORMATION...AND FURTHER W AS A RESULT.  STILL
SOME SMALL DIFFS AND EXPECT TO SEE SOME WOBBLING THE NEXT DAY OR
TWO.  UNFORTUNATELY...WHEN DEALING WITH CUTOFF UPPER LOWS...EVERY
WOBBLE WILL MAKE A PRETTY BIG DIFFERENCE ON RAIN CHCS AND TEMPS.

THE LATEST ITERATION FROM THE 00Z MODELS HAS A GENERAL CONSENSUS ON
THE UPPER LO FORMING AROUND THE INTERSECTION OF KS-MO-OK-AR ON
FRIDAY AND THEN GRADUALLY PULLING NWD THRU SATURDAY.  THOSE SLIGHT
DIFFS WILL MAKE A BIG DEAL AT THE SFC...WHERE ECMWF SHOWS A MORE
AGGRESSIVE CDFNT PUSH ON THURSDAY WITH NOTHING OF THE SORT FROM THE
GFS AND SO A LARGE TEMP FCST DIFF AS A RESULT ARISES...ESPECIALLY
THURSDAY NIGHT AND FRIDAY.  A BROAD CONSENSUS APPROACH PREFERRED FOR
TEMPS AS A RESULT.

ONE THING THAT LOOKS INCREASINGLY LIKELY IS THE RAIN CHCS...
ESPECIALLY IF THE UPPER LO SETS UP IN THE RIGHT SPOT ALMOST LIKE
MODELS DEPICT NOW...COULD BE SOME HEAVY RAINFALL POTENTIAL AS IT
TAPS INTO GULF OF MEXICO MOISTURE.

TES

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN APR 28 2013
MVFR FLIGHT CONDITIONS WILL PREVAIL ACROSS MUCH THE AREA FOR THE
REST OF THE DAY...WITH PATCHES OF IFR CONTINUING OVER PARTS OF
SOUTHWEST ILLINOIS. CONDITIONS WILL GRADUALLY IMPROVE THROUGH THE
AFTERNOON...WITH MOST OF THE AREA CLEARING OUT BY MID-LATE
EVENING. EXPECT SOME MVFR FOG ALONG AND EAST OF THE MISSISSIPPI
RIVER LATE TONIGHT WITH AREAS OF IFR PROBABLY DEVELOPING OVER
PARTS OF SOUTHWEST/SOUTH CENTRAL ILLINOIS WHERE THE WIND WILL BE
LIGHTEST.

SPECIFICS FOR KSTL...
MVFR CIGS BELOW 2000FT WILL PREVAIL FOR A FEW MORE HOURS AT
LAMBERT BEFORE LIFTING ABOVE 2000FT. CURRENT THINKING IS THAT
CLOUDS SHOULD SCATTER OUT EARLY THIS EVENING. NOT SURE WHAT TO DO
ABOUT FOG POTENTIAL AT THIS TIME. THINK THERE WILL BE FOG IN THE
STL METRO AREA...MOST LIKELY 3-5SM VSBYS...BUT LAMBERT TENDS TO BE
LESS FOGGY THAN OTHER STATIONS. HAVE NOT INCLUDED FOG IN THE
CURRENT TAF...BUT WILL MENTION FOG POTENTIAL TO THE EVENING SHIFT.


CARNEY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 252 PM CDT SUN APR 28 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013

PRIMARY FORECAST CONCERN WILL BE SMALL CHANCES FOR THUNDERSTORMS
LATE THIS AFTERNOON AND EVENING IN THE NORTHEAST PART OF THE CWA
AND THEN ANOTHER SMALL CHANCE FOR SHOWERS IN THE NORTH PART OF THE
CWA OVERNIGHT.

UPPER AIR ANALYSIS AND CURRENT WATER VAPOR IMAGERY SHOW AN UPPER
LEVEL TROUGH MOVING ACROSS THE EASTERN THIRD OF THE COUNTRY WHILE
MORE OF A ZONAL FLOW IS NOTED FROM THE PACIFIC NW INTO THE CENTRAL
PLAINS. THERE ARE A COUPLE OF WEAK SHORT WAVES TO DEAL
WITH...ESPECIALLY ONE MOVING INTO MONTANA WHICH COULD PROVIDE SOME
FORCING ACROSS THE NORTHERN PART OF OUR CWA LATER TONIGHT.

AT THE SURFACE...A TROUGH OF LOW PRESSURE WAS JUST MOVING INTO THE
FAR WESTERN PART OF THE CWA BY 19Z. TEMPERATURES HAVE CLIMBED
STEADILY TODAY AND MOST LOCATIONS SHOULD HIT THE 80S BEFORE THE
AFTERNOON IS OUT. DEW POINTS RANGE FROM THE MID TO UPPER 40S EAST OF
THE SURFACE TROUGH...IN THE MID 30S ALONG THE TROUGH AXIS...AND THEN
DIPPING INTO THE MID 20S 50 TO 100 MILES BEHIND THE TROUGH.
REGARDING FIRE WEATHER CONCERNS...RELATIVE HUMIDITIES HAVE FALLEN
NEAR OR BELOW 20 PERCENT IN THE WEST...BUT WINDS SHOULD STAY BELOW
20 MPH IN THAT PART OF OUR CWA AS THE TROUGH AXIS LIES OVER THAT
AREA. BY THE TIME THE WINDS PICK UP AGAIN FROM THE NW...WE SHOULD BE
A FEW HOURS PAST MAX HEATING.

VARIOUS SHORT RANGE MODELS SHOWING SOME DECENT INSTABILITY AHEAD OF
THE SURFACE TROUGH WHICH COULD TRIGGER CONVECTION LATER THIS
AFTERNOON. BOTH THE HRRR AND THE 4KM WRF SHOWING TSTM DEVELOPMENT IN
THE NORTHEAST PART OF THE CWA FROM ROUGHLY 5 PM THROUGH 10 PM. WHILE
BETTER CHANCES SEEM TO BE JUST A LITTLE FURTHER NORTHEAST THAN OUR
CWA...WILL CONTINUE WITH AT LEAST A SLIGHT CHANCE IN OUR NORTHEAST
AS WE COULD CERTAINLY GET CLIPPED.

THE SHORTWAVE NOTED ABOVE SHOULD HAVE MORE OF AN IMPACT AFTER
MIDNIGHT AND CONTINUED THE CHANCE OF SHOWERS MAINLY IN THE
NORTHEASTERN HALF OF THE CWA. FORCING AND MOISTURE NOT OVERLY
IMPRESSIVE AND WILL KEEP POPS FAIRLY LOW. INSTABILITY ALSO DROPS OFF
QUITE A BIT SO WILL KEEP THUNDER MENTION OUT AFTER MIDNIGHT.

QUIET WEATHER EXPECTED ON MONDAY AS WE AWAIT THE APPROACH OF THE
NEXT SYSTEM UPSTREAM. WITH EASTERLY FLOW AT SURFACE...HIGH
TEMPERATURES SHOULD BE JUST A LITTLE BIT COOLER THAN WHAT WE ARE
SEEING TODAY...BUT ALL IN ALL STILL NOT BAD.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013

THE WEATHER PATTERN WILL UNDERGO CHANGES DURING THE EXTENDED PERIODS
WITH A TREND TO COOLER SPRING CONDITIONS.

ON MONDAY NIGHT AN UPPER TROUGH DIGS SOUTH ACROSS THE
NORTHWEST/NORTH CENTRAL TIER STATES AND A SFC COLD FRONTAL BOUNDARY
PUSHES SOUTH FM THE DAKOTAS...AND IS EXPECTED TO STRETCH FM
ROUGHLY KOMA TO KPHG TO SOUTH OF KGLD BY 12Z TUESDAY. WITH FRONT
CROSSING MUCH OF OUR NEB CWA OVERNIGHT...CONSIDERED SOME LOW POPS
TOWARD TUESDAY MORNING BUT CHCS APPEAR HIT OR MISS AND WILL CARRY
SILENT POPS FOR NOW. IN GENERAL...MODELS HAVE CONTINUED TO TREND
FASTER WITH FROPA...WITH THE NAM REMAINING FASTER THAN GFS. THE
FARTHER SOUTH FRONTAL POSITION NEAR THE NEB/KS STATELINE OR IN
NORTHERN KANSAS PLACES CHCS FOR AFTN CONVECTION FARTHER SOUTH AS
WELL. DEPENDING ON TIMING/FRONTAL POSITION THERE STILL APPEARS TO
BE A WINDOW OF OPPORTUNITY...ALBEIT A SHRINKING WINDOW...FOR
POTENTIALLY A STRONG/SEVERE TSTMS IN THE LATE AFTN/EVE FOR OUR
SOUTHEAST ZONES. SOME PRESENCE OF ELEVATED INSTABILITY IS
MAINTAINED INTO THE FIRST PART OF THE NIGHT TUESDAY NIGHT WHICH
SHIFTS SOUTH BY WEDNESDAY MORNING. OVERALL PCPN CHCS INCREASE OVERNIGHT
TUESDAY NIGHT ACROSS OUR ENTIRE CWA IN INCREASING ISENTROPIC LIFT
AHEAD OF THE UPPER TROUGH MOVING ONTO THE CENTRAL PLAINS AND IN
PRESENCE OF STRONG MID LEVEL FRONTOGENESIS. MUCH COLDER AIR
ADVECTS SOUTH BEHIND THE FRONTAL BOUNDARY AND THE R/S LINE ACROSS
WESTERN NEBRASKA LOOKS TO EDGE CLOSE TO OUR NW CWA TOWARDS
WEDNESDAY MORNING.

WEDNESDAY IS SHAPING UP TO BE A COLD...WET...BREEZY/WINDY DAY UNDER
INFLUENCE OF UPPER TROUGH MOVING IN WITH THE BETTER CHCS FOR PCPN
EXPECTED IN THE FIRST PART OF THE DAY BEFORE DRIER AIR ADVECTS IN
FOLLOWING MID LEVEL TROUGH...BUT THIS WILL BE DEPENDENT UPON
SYSTEMN TIMING WITH GFS MORE PROGRESSIVE THAN ECMWF.

MODELS CONTINUE TO DEVIATE ON WHERE UPPER LOW WILL CLOSE OFF
THURS NIGHT/FRI DUE TO A BLOCKING RIDGE TO THE EAST. 24HRS AGO
THE 12Z MODELS CLOSED THE LOW ACROSS THE CENTRAL PLAINS...THEN
THE 00Z SUNDAY RUN OF MODELS CLOSED THE LOW IN EASTERN KS/SOUTHERN
MISSOURI...AND NOW THE 12Z GFS RUN CLOSES THE LOW EAST OF THE
MISSOURI RIVER IN IOWA WITH THE POTENTIAL FOR A CUTOFF SYSTEM TO
LIFT AND RETROGRADE TOWARD THE END OF THE WORKWEEK AND INTO THE
FIRST PART OF NEXT WEEKEND. THE 12Z ECMWF IS A LITTLE MORE SIMILAR
TO ITS PREVIOUS RUN INITIALLY WITH THE SYSTEM CLOSING OFF IN
EASTERN KS WITH THE CUTOFF UPPER LOW MEANDERING ACROSS MISSOURI
THRU THE WEEKEND. PCPN CHCS WILL BE DEPENDENT UPON THE UPPER LOW
PRESSURE SYSTEM POSITION AND IT IS JUST TOO EARLY TO PINPOINT THE
BEST CHCS/TIMING JUST YET GIVEN THE VARYING MODEL SOLUTIONS AND
DID NOT DEVIATE MUCH FROM THE EXTENDED INIT. UNDER THE INFLUENCE
OF THE UPPER LOW/TROUGH PATTERN...TEMPERATURES WILL REMAIN COOL WITH HIGHS
MAINLY 50S...AND LOWS IN THE 30S...ALTHOUGH READINGS COULD RECOVER
SOME IF LOW KICKS OUT TOWARD DAY 7. WITH LOWS IN THE 30S WILL NEED
TO CLOSELY MONITOR POTENTIAL FOR FROST/FREEZE AS SPRING HEADLINES
FOR THIS BEGIN MAY 1.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1219 PM CDT SUN APR 28 2013

EXPECT VFR CONDITIONS DURING THE FORECAST PERIOD. A SURFACE TROUGH
MOVING EAST ACROSS THE REGION WILL SWITCH WINDS FROM SOUTH TO
SOUTHWEST AND EVENTUALLY TO THE NORTH LATER THIS AFTERNOON AND
INTO TONIGHT. SPEEDS SHOULD RANGE IN THE 10-15 KT RANGE. JUST A VERY
SMALL CHANCE FOR ANY CONVECTION TO DEVELOP ALONG THIS TROUGH LATE
THIS AFTERNOON AND WILL NOT PUT IN THE TAF BUT WILL CONTINUE TO MONITOR.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.

&&

$$

SHORT TERM...EWALD
LONG TERM...FAY
AVIATION...EWALD







AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

 107 PM CDT SUN APR 28 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN APR 28 2013

SFC WINDS SHOULD INCREASE FROM THE WEST TOWARD MORNING AHEAD OF A
PACIFIC COLD FRONT FCST TO MOVE THROUGH DURING THE AFTN. THE RAP
SUPPORTS HIGHS IN THE MID 80S AHEAD OF THE FRONT ACROSS SWRN NEB AND
WINDS SHOULD INCREASE TO 15 TO 25 MPH AHEAD AND BEHIND THE FRONT.

FOR TONIGHT...A DISTURBANCE...CURRENTLY ACROSS THE NRN ROCKIES WILL
MOVE THROUGH NRN NEB. K INDICES SUPPORT TSTMS WEST OF HIGHWAY 83.
MOISTURE BELOW 700MB IS VERY LIMITED EAST OF 83 AND LAPSE RATES
NEARLY MOIST ADIABATIC.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN APR 28 2013

GUSTY SOUTHERLY WINDS AND CRITICALLY LOW RELATIVE HUMIDITY VALUES TO
BE EXPECTED ONCE AGAIN MONDAY AFTERNOON...WITH THE POTENTIAL OF
WIDESPREAD RED FLAG CONDITIONS.  FIRE HEADLINES MAY BE NECESSARY
ONCE AGAIN.  A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE
HIGH PLAINS ON MONDAY...ALLOWING FOR DOWNSLOPING SOUTHWESTERLY TO
WESTERLY WINDS AND HIGHS WELL INTO THE UPPER 70S...IF NOT LOW 80S.
WIND GUSTS WILL LIKELY EXCEED 25 MPH DURING PEAK HEATING AS THE
PRESSURE GRADIENT INCREASES AND STRONG TROPOSPHERIC MIXING
COMMENCES.  PREVIOUS FORECAST HAD HIGHS HANDLED WELL FOR
MONDAY...WITH ONLY MINOR UPWARD TWEAKS NEEDED ACROSS NORTHWESTERN
NEBRASKA...WHERE TEMPERATURES MAY SOAR IN ADVANCE OF A COLD FRONTAL
PASSAGE.  THE FRONT IS CURRENTLY PROGGED TO ARRIVE OVERNIGHT
MONDAY/EARLY TUESDAY...HOWEVER THERE IS LITTLE SUPPORT FOR
PRECIPITATION PRODUCTION INITIALLY.  PROXIMITY SOUNDINGS REVEAL VERY
LITTLE MOISTURE IN THE LOWER LEVELS...THUS WILL CONTINUE THE SILENT
14 POPS THROUGH THE OVERNIGHT.  TEMPERATURES HOWEVER WILL BE
NOTICEABLY COOLER ON TUESDAY...BUT THERE REMAINS DIFFERENCES BETWEEN
THE DETERMINISTIC SOLUTIONS IN THE AMOUNT OF COOLING...THE CONSENSUS
WOULD SUGGEST A 20-25F DECREASE IN HIGHS FROM MONDAY...WILL GO WITH
A RANGE OF HIGHS FROM THE MID 50S TO LOW 60S ACROSS THE CWA.  ALONG
WITH THE COOLER TEMPERATURES...PRECIPITATION CHANCES INCREASE
TUESDAY INTO WEDNESDAY AS A MIDLEVEL SHORTWAVE AND ASSOCIATED RRE OF
A 110 PLUS KT UPPER JET ADVANCES ON THE REGION.  THE HIGHEST QPF
WILL BE TIED TO THE MID-LEVEL FRONTOGENETIC FORCING WHICH SHOULD
BISECT THE CWA FROM SOUTHWEST TO NORTHEAST...WHICH MEANS CHANCES ARE
INCREASING FOR WELCOME WIDESPREAD QPF ACROSS THE HEART OF THE
SANDHILLS.  PTYPE MAY BECOME PROBLEMATIC EARLY ON WEDNESDAY...AS H85
TEMPERATURES ARE SHOWN TO FALL AS COLD AS -3C BY 12Z WEDNESDAY.
WILL INTRODUCE A RAIN/SNOW MIX ACROSS NORTHWEST NEBRASKA FROM
06Z-12Z...BUT NOT EXPECTING ANY ACCUMULATIONS AS GROUND TEMPERATURES
HAVE WARMED GREATLY.  GUIDANCE CAME IN COOLER ONCE AGAIN FOR
WEDNESDAY...AND GIVEN EXPECTED CLOUDY CONDITIONS WITH WEAK OR
NEUTRAL CAA...HIGHS IN THE LOWER 40S SHOULD BE THE NORM.  THE
REMAINDER OF THE EXTENDED FORECAST REMAINS INTERESTING AS A CLOSED
LOW DEVELOPS OVER CENTRAL KANSAS ON THURSDAY...AND THEREAFTER
MEANDERS AIMLESSLY THROUGH THE MISSOURI VALLEY/CORN BELT THROUGH THE
WEEKEND.  WITH BROAD CYCLONIC FLOW REMAINING ACROSS THE CENTRAL
CONUS...WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES INTO NEXT
WEEKEND WITH CONTINUED SLIGHT CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM CDT SUN APR 28 2013

ANOTHER HOT DAY WITH VFR CONDITIONS EXPECTED THIS AFTERNOON. A
WEAK COLD FRONT WILL CAUSE A SLIGHT WIND SHIFT FROM THE
WEST/NORTHWEST TO THE NORTH. WINDS SPEEDS WILL BE SIMILAR BOTH
AHEAD AND BEHIND THE FRONT...GUSTING TO 20 TO 25 KTS. A WEAK
DISTURBANCE WILL MOVE ACROSS THE AREA TONIGHT...AND SHOULD BE
ENOUGH TO SPARK SOME ISOLD/SCT SHOWERS AND THUNDERSTORMS...MAINLY
TO IMPACT NORTHERN NEB. FURTHER SOUTH AN INCREASE OF MID/HIGH
CLOUDS...HOWEVER DRIER LOWER LEVEL ATMOSPHERE SHOULD PREVENT ANY
DEVELOP. SYSTEM MOVES THROUGH QUICKLY WITH VFR AND DRY CONDITIONS
FOR MONDAY...WINDS DO BECOME SOUTHERLY DURING THE LATE MORNING
HOURS.

&&

.FIRE WEATHER...
ISSUED AT 337 AM CDT SUN APR 28 2013

RED FLAG CONDITIONS SHOULD DEVELOP AHEAD AND BEHIND THE COLD FRONT
FORECAST TO MOVE THROUGH SWRN NEB THIS AFTN. THE RAP AND HRRR ARE
LEADING THE WAY WITH DEW PTS IN THE 20S WHILE THE MOSGUIDE WIND
GUSTS ARE IN THE 20 TO 24 KT RANGE. THE DRIER MODEL DATA AND
STRONGER WIND GUSTS HAVE BEEN VERIFYING BETTER THAN THE WETTER
MODELS WHICH HAVE BEEN AS MUCH AS 10F TOO HIGH WITH DEW POINTS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
NEZ204-206-209-210-219.

&&

$$

SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...MASEK
FIRE WEATHER...CDC







AREA FORECAST DISCUSSION

NWS HASTINGS NE

 1219 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 544 AM CDT SUN APR 28 2013

UPDATED THE FORECAST TO INCLUDE MENTION OF 1 MILE WITH THE FOG IN
THE FAR SOUTHEAST THIS MORNING AND TO INCLUDE SPRINKLES DOWN TO
THE STATE LINE LATE TONIGHT AS MORE MODELS ARE INDICATING SOME
POSSIBLE QPF...BUT AIR SHOULD BE SO DRY THAT SPRINKLE SHOULD
SUFFICE FARTHER TO THE SOUTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM CDT SUN APR 28 2013

BIGGEST CHALLENGE WILL BE DETERMINING EXTENT OF SOME POTENTIAL FOG
AND STRATUS IN THE SOUTHEASTERN CWA THIS MORNING...PLUS THE
POTENTIAL OF ISOLATED THUNDERSTORMS LATE THIS AFTERNOON/EVENING
NORTHEAST/EAST...AND ALSO A CHANCE OF RAIN LATE TONIGHT.
ALSO...DETERMINING THE HIGH TEMPERATURE TODAY COULD BE A BIT TRICKY.
ALSO...WE WILL BE APPROACHING ELEVATED FIRE DANGER FOR ROUGHLY OUR
NORTHWESTERN QUADRANT OF THE CWA.

THE HRRR WAS SPOT ON WITH FOG AND STRATUS YESTERDAY. WITH THE BEST
TRANSPORT OF MOISTURE SHIFTED SOUTHEAST...THE HRRR APPEARS TO BE ON
TRACK WITH DEVELOPING STRATUS AND FOG TO THE SOUTH. CURRENT
INTERPOLATIONS STILL CLIP US WITH STRATUS AND FOG IN OUR SOUTHEAST
EARLY THIS MORNING...MAINLY AFFECTING OUR 5 SOUTHEASTERN-MOST
COUNTIES. THIS IS EXTREMELY SHALLOW AND SHOULD NOT TAKE LONG TO BURN
OFF BY MID-MORNING.

THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY EAST...BUT WILL
STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY SOUTH ACROSS THE
CWA...COMING FROM THE NORTHERN PLAINS. WITH LOWERING DEWPOINTS FOR
MUCH OF THE CWA...ALONG WITH THE POTENTIAL FOR COMPRESSIONAL WARMING
AND VERY WARM 850 MB TEMPERATURES...I HAVE INCREASED HIGH
TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID 80S. JUDGING BY
RECENT MODEL PERFORMANCE...THIS IS THE DIRECTION TO TAKE.

ALSO...WE COULD GET AN ISOLATED THUNDERSTORM AS THE COLD FRONT MAKES
ITS WAY SOUTH...ESPECIALLY NORTHEAST/EAST WHERE INSTABILITY IS A
LITTLE HIGHER. BULK SHEAR WILL BE MARGINAL FOR SEVERE WEATHER...BUT
WE SHOULD HAVE JUST ENOUGH INSTABILITY TO THROW IN A MENTION OF
PERHAPS SOME HAIL UP TO THE SIZE OF NICKELS ALONG AND EAST OF
HIGHWAY 14.

A MID-LEVEL WAVE COULD GIVE US POST-FRONTAL SHOWER ACTIVITY IN THE
NORTH. THERE DOES NOT APPEAR TO BE ENOUGH MID-LEVEL INSTABILITY TO
SUPPORT THUNDER. ENSEMBLES SUGGEST RAIN POTENTIALLY FARTHER
SOUTH...BUT THIS DOES NOT APPEAR TO BE A POPULAR SOLUTION ON HIGH
RESOLUTION SHORT RANGE MODELS...SO I WILL CONTINUE TO FOCUS CHANCES
IN OUR NORTHERN CWA. THE 06Z RUN DOES INDICATE POSSIBLE RAIN AS FAR
SOUTH AS THE STATE BORDER...POSSIBLY HELPED BY A WEAK AREA OF LEFT
INDUCED BY THE RIGHT REAR QUADRANT OF AN EXTREMELY MODELS JET
STREAK.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 515 AM CDT SUN APR 28 2013

ALTHOUGH UNCERTAINTY REMAINS HIGH IN THE DETAILS...THE GENERAL
THEME OF THIS 6-DAY PERIOD HAS CHANGED LITTLE OVER THE PAST 24
HOURS...WITH AT LEAST ONE MORE DAY OF ABOVE NORMAL WARMTH ON
MONDAY FOLLOWED BY THE PASSAGE OF A STRONG COLD FRONT
TUESDAY/TUESDAY NIGHT...WITH WELL BELOW NORMAL TEMPS THEN
PREVAILING THROUGH THE REMAINDER OF THE WEEK...ALTHOUGH THE JURY
IS STILL OUT ON JUST HOW COLD. PRECIP-WISE...ALL OR PART OF THE
CWA NOW HAS POPS MENTIONED FOR 9 CONSECUTIVE FORECAST PERIODS FROM
TUESDAY AFTERNOON THROUGH SATURDAY. THIS IS NOT AN IDEAL SITUATION
FOR PUBLIC FORECAST PRODUCTS AS IT OFTEN CREATES THE IMPRESSION
THAT IT WILL BE WETTER THAN IT ACTUALLY ENDS UP BEING...BUT GIVEN
MODEL VARIABILITY ITS JUST THE WAY IT IS FOR NOW. IN ALL REALITY
THOUGH...SOME OF THESE POPS MAY EVENTUALLY BE REDUCED/CUT IN
LATER FORECASTS...AS MODELS CONTINUE TO VARY CONSIDERABLY FROM
RUN-TO-RUN WITH THE PLACEMENT/LIKELIHOOD OF PRECIP POTENTIAL
BEYOND WEDNESDAY NIGHT. AT THIS POINT...BY FAR THE BEST CHANCES
FOR WIDESPREAD RAIN...AND POSSIBLY EVEN SOME SNOW MIXED
IN...OCCURS BETWEEN TUESDAY NIGHT AND WEDNESDAY NIGHT...WITH
UNCERTAINTY RAMPING UP THEREAFTER. THERE ALSO REMAINS A RISK FOR
STRONG/SEVERE STORMS TUESDAY AFTERNOON BUT LIKELY MORE SO TUESDAY
EVENING. ON TO THE DETAILS...

MONDAY/MONDAY NIGHT...CONFIDENCE REMAINS REASONABLY HIGH IN A DRY
24 HOURS. VARIOUS 00Z MODELS SUCH AS THE NAM/GFS/ECMWF AGREE THAT
THE LARGE SCALE PICTURE ALOFT FEATURES QUASI-ZONAL FLOW...AS ONE
LOW AMPLITUDE SHORTWAVE TROUGH DEPARTS EAST OF THE CWA DURING THE
DAY...WHILE UPSTREAM AN UPPER JET STREAK STARTS CARVING OUT
LARGER...BROADER TROUGH OVER THE NORTHERN ROCKIES/NORTHERN PLAINS.
RIGHT AWAY IN THE MORNING...IT COULD BE A CLOSE CALL WHETHER OR
NOT A BRIEF PERIOD OF LINGERING SPRINKLES/LIGHT SHOWERS FROM THE
SUNDAY NIGHT PERIOD COULD STILL BE SKIRTING EASTERN ZONES...BUT
VARIOUS MODELS INCLUDING REFLECTIVITY PROG FROM 4 KM WRF-NMM SHOVE
THIS ACTIVITY EAST BY 12Z SO WILL KEEP THE OFFICIAL MORNING PERIOD
PRECIP-FREE. LATER IN THE DAY...MODELS SUCH AS THE NAM BUILD A
HEALTHY AREA OF 2000+ J/KG SURFACE-BASED CAPE IN SOUTHEAST
COUNTIES...BUT NOT THINKING MUCH OF A THUNDERSTORM THREAT DUE TO
LIMITED FORCING AND PLENTY OF CAPPING EVIDENT IN FORECAST
SOUNDINGS. FURTHERMORE...THE MAGNITUDE OF MODELED INSTABILITY IS
LIKELY A BIT OVERDONE DUE TO OVERDONE SURFACE DEW POINT VALUES.
ASSUMING NO CONVECTION FIRES...IT SHOULD BE A QUIET AND MILD DAY
AS SURFACE BREEZES GENERALLY 10-15 MPH TRANSITION FROM EASTERLY TO
SOUTHERLY. GIVEN SLIGHTLY COOLER 850MB TEMPS AND LESS FAVORABLE
MIXING THAN TODAY...ANTICIPATE A SLIGHTLY COOLER MONDAY...AND MADE
LITTLE CHANGE TO HIGHS RANGING FROM MID 70S FAR NORTH TO LOW 80S
SOUTHWEST. LATE MONDAY NIGHT...THERE IS DECENT MODEL CONSENSUS
THAT THE LEADING EDGES OF THE COLD FRONT RACES SOUTHEAST INTO THE
NORTHWESTERN CWA BEFORE SUNRISE...ALTHOUGH THE NAM/GFS SEEM TO BE
FASTER WITH THIS FRONTAL INVASION THAN THE ECMWF. THE LATEST 06Z
NAM IS NOW SUGGESTING A NARROW LINE OF SHOWS/STORMS COULD BRUSH
FAR NORTHERN ZONES LATE MONDAY NIGHT JUST BEHIND THIS FRONT...BUT
WITH LIMITED SUPPORT FROM OTHER SOLUTIONS WILL OMIT ANY PRECIP
MENTION FOR NOW ALTHOUGH IT BEARS WATCHING. MADE LITTLE CHANGE TO
LOW TEMPS WITH LOW-MID 50S MOST AREAS EXCEPT UPPER 40S FAR
NORTHWEST.

TUESDAY/TUESDAY NIGHT...THINGS BECOME MORE ACTIVE ITS JUST A
MATTER OF HOW MUCH SO. ALOFT...THE NORTHERN ROCKIES/NORTHERN
PLAINS TROUGH AMPLIFIES IN A POSITIVELY TILTED FASHION...WHILE IN
THE LOW LEVELS THE FAIRLY STRONG COLD FRONT CONTINUES TO SWEEP
SOUTHWARD ACROSS THE CWA...AND HAVE INCREASED NORTH-NORTHEAST
SUSTAINED WIND SPEEDS TO AROUND 20 MPH IN ITS WAKE. FOR SOME
REASON...THE 00Z ECMWF IS STARTING TO LOOK LIKE MORE OF AN OUTLIER
WITH ITS SLOWER COLD FRONTAL PASSAGE...ALTHOUGH THE NAM MAY BE A
BIT TOO AGGRESSIVE. THIS UNCERTAINTY IN THE MAGNITUDE OF DAYTIME COLD
AIR ADVECTION RESULTS IN QUITE A BIT OF UNCERTAINTY IN HIGH
TEMPS...AND COULD EASILY SEE CURRENT FORECAST BEING 5-10 DEGREES
OFF FROM CURRENTLY ADVERTISED VALUES...WHICH ARE A MULTI-MODEL
BLEND. LEANING TOWARD THE FASTER COLD AIR INVASION...NUDGED DOWN
HIGHS ROUGHLY 3-4 DEGREES FROM PREVIOUS...AIMING FOR A DECENT
GRADIENT FROM NEAR 60 FAR NORTH TO UPPER 70S FAR SOUTHEAST. AS FOR
CONVECTIVE POTENTIAL...HELD OFF ANY MENTION OF DAYTIME STORMS
UNTIL POST-21Z...AND KEPT THE EXACT SAME AREA FROM PREVIOUS
FORECAST MAINLY SOUTH OF A YORK-ALMA LINE IN CLOSEST PROXIMITY TO
THE SURFACE FRONT. HOWEVER...IF THE FASTER FRONTAL SOLUTIONS SUCH
AS THE NAM VERIFY THEN THE PRIMARY LOW LEVEL INSTABILITY AXIS AND
RESULTANT RISK FOR POTENTIALLY NEAR-SURFACE BASED STORMS WOULD
ACTUALLY FOCUS SOUTHEAST OF THE CWA. THIS COULD BE A CLOSE CALL.
OF GREATER CONFIDENCE AT THIS POINT IS AN INCREASE IN COVERAGE OF
EVENING/OVERNIGHT PRECIPITATION WELL-BEHIND THE SURFACE
FRONT...AS LARGE SCALE MID LEVEL CONVERGENCE MOVES IN FROM THE
NORTHWEST. EVEN IF THE CWA IS SPARED SURFACE-BASED STORMS...IT
STILL LOOKS LIKE A FAIRLY AGGRESSIVE DEVELOPMENT OF AT LEAST
SLIGHTLY ELEVATED STORMS WILL FLARE UP NEAR OR SHORTLY AFTER
SUNSET IN RESPONSE TO INCREASING MOISTURE TRANSPORT/WIND
CONVERGENCE INTO THE MID-LEVEL FRONTAL ZONE EVIDENT AT 700MB.
WHILE HAIL WOULD LIKELY BE THE MAIN THREAT WITH THESE STORMS...THE
MAGNITUDE OF THE SEVERE RISK WILL ULTIMATELY DEPEND ON THE AMOUNT
OF ELEVATED INSTABILITY...WITH THE LATEST NAM ONLY ADVERTISING
LESS THAN 500 J/KG IN THE 850-700MB LAYER...BUT THE GFS STILL
CLOSER TO 1000 J/KG. DEEP LAYER SHEAR WILL BE PLENTY STRONG TO
SUPPORT AT LEAST MARGINAL SEVERE...AVERAGING AROUND 50KT.
CERTAINLY THE MAIN SEVERE THREAT AREA SHOULD FOCUS ACROSS ROUGHLY
THE SOUTHEAST 1/3 OF THE CWA...AND WILL BE MAKING LITTLE CHANGE
TO HAZARDOUS WEATHER OUTLOOK WORDING. EVEN NORTH OF THE MAIN
THUNDERSTORM AREA...WIDESPREAD RAIN SHOWERS SHOULD BREAK OUT
DURING THE NIGHT...AND POPS WERE RAISED TO 70 PERCENT ACROSS
NEARLY THE ENTIRE CWA. ALTHOUGH THE NAM/GFS THERMAL PROFILES
SUGGEST THAT SOME WET SNOW COULD MIX IN WITH RAIN MAINLY IN FAR
NORTHWEST ZONES LATE IN THE NIGHT...WILL KEEP PRECIP TYPE AS ALL
RAIN FOR NOW...DESPITE LOW TEMPS AIMED FROM MID 30S NORTHWEST TO
MID 40S SOUTHEAST.

WEDNESDAY/WEDNESDAY NIGHT...BY THIS TIME THE CWA IS FIRMLY IN THE
GRIPS OF THE COLDER REGIME. THE 00Z ECMWF/GFS RUNS ARE IN BETTER
AGREEMENT THAN 24 HOURS AGO ON THE SYNOPTIC SCENE...AS THEY BOTH
SLOWLY SHIFT THE INCREASINGLY-AMPLIFIED BUT STILL POSITIVELY
TILTED MID-UPPER TROUGH FROM THE NORTHERN PLAINS/CENTRAL ROCKIES
INTO THE CENTRAL PLAINS...WHILE AT THE SURFACE BREEZY NORTH WINDS
PERSIST. THE DOWNWARD NUDGING TO DAYTIME HIGHS CONTINUES...AND NOW
HAVE ALL BUT THE FAR SOUTHEAST CWA ONLY TOPPING OUT SOMEWHERE IN
THE 40S...WITH FURTHER DOWNWARD NUDGES STILL VERY MUCH POSSIBLE
GIVEN THAT PRECIP IS STILL EXPECTED TO BE FAIRLY WIDESPREAD DURING
THE DAY AS THE SOUTHWEST-NORTHEAST ORIENTED MID LEVEL
FRONTOGENETIC ZONE CENTERS OVERHEAD. AT LEAST FOR ONE MORE
FORECAST CYCLE...HAVE LEFT DAYTIME PRECIP TYPE AS RAIN-
ONLY...ALTHOUGH ITS BECOMING INCREASINGLY LIKELY THAT AT LEAST A
MIX WITH SNOW MAY SOON NEED INSERTED ESPECIALLY IN NORTHWEST
AREAS...ESPECIALLY IF HIGH TEMPS CONTINUE A DOWNWARD TREND. BY
THIS TIME INSTABILITY SHOULD BE MINIMAL EVEN IN SOUTHEAST COUNTIES
AND WILL LEAVE OUT THUNDER. POPS WERE UPPED TO 60 PERCENT
LIKELIES IN MOST AREAS...AS THIS IS SHAPING UP TO BE A RATHER WET
AND VERY RAW FIRST DAY OF MAY. WEDNESDAY NIGHT...KEPT AT LEAST
30-50 POPS GOING ALL AREAS FOR A RAIN/SNOW MIX WITH A LIGHT SNOW
ACCUMULATION NOT OUT OF THE QUESTION...ALTHOUGH BOTH THE ECMWF/GFS
ARE IN DECENT AGREEMENT PUSHING PRECIP OUT FROM NORTHWEST-
SOUTHEAST AS THE NIGHT WEARS ON. KEPT LOW TEMPS BARELY ABOVE
FREEZING ACROSS MOST OF THE CWA WEDNESDAY NIGHT...BUT ANY FROST
THREAT WOULD SEEM VERY MINIMAL GIVEN ONGOING PRECIP AND CONTINUED
MODEST NORTH BREEZES.

TURNING TO THE THURSDAY THROUGH SATURDAY TIME FRAME IN LESS
DETAILED FASHION...THE ONE BIT OF GOOD NEWS IS THAT THE ECWMF/GFS
SOLUTIONS ARE NOW IN INCREDIBLY GOOD AGREEMENT...AT LEAST FOR NOW...ON
THE EVOLUTION OF THE TIGHTLY WOUND CLOSED MID LEVEL LOW THAT IS
FORECAST TO DEVELOP ACROSS THE CENTRAL CONUS AS THE PARENT LARGE
SCALE TROUGH AXIS RUNS INTO A SOLID WALL IN THE FORM OF A STOUT
OMEGA BLOCK RIDGE OVER THE EASTERN CONUS. THE BEGINNING STAGES OF
THIS CLOSING OFF PROCESS TAKES PLACE THURS/THURS NIGHT...GENERALLY
CENTERED SOMEWHERE BETWEEN NORTHERN OK AND EASTERN KS. THIS IS
FARTHER EAST IN THE ECMWF FROM PREVIOUS RUNS...WITH THIS MODEL NOW
ACTUALLY KEEPING MOST OF THE CWA DRY FROM THURS AFTERNOON THROUGH
FRIDAY EVENING. HOWEVER...GIVEN PLENTY OF UNCERTAINTY IN THIS
LATEST SOLUTION WILL KEEP LOW POPS FOR EITHER CHILLY RAIN OR A
RAIN/SNOW MIX GOING ACROSS PART OR ALL OF THE CWA THIS ENTIRE TIME
FOR NOW. BY FRIDAY NIGHT INTO SATURDAY...BOTH OF THESE MODELS LIFT
THE CLOSED LOW BACK NORTH FROM MO TOWARD IA...WITH EVEN THE ECMWF
WRAPPING PRECIP CHANCES WESTWARD BACK INTO AT LEAST THE EASTERN
CWA BY THIS TIME. DAILY/NIGHTLY TEMPERATURES WILL DEPEND SO MUCH
ON WHETHER OR NOT WIDESPREAD CLOUDS AND/OR PRECIP ARE
PRESENT...BUT AT LEAST FOR NOW CONTINUED THE DOWNWARD TREND FOR
HIGH TEMPS THURS-SAT...WITH MAINLY UPPER 40S NOW THURS AND LOW 50S
FRI-SAT. OVERNIGHT LOWS BOTH FRI AND SAT MORNING ARE FORECAST
RIGHT AROUND OR JUST BELOW THE 32 DEGREE FREEZING MARK...BUT
HOLDING ABOVE THE 28 DEGREE HARD FREEZE THRESHOLD. AT THE VERY
LEAST...MAY EVENTUALLY HAVE TO INSERT A FROST MENTION FOR FRIDAY
MORNING...BUT CONFIDENCE IS TOO LOW AT THIS TIME RANGE...AND THERE
ARE ALREADY PLENTY MORE IMMEDIATE ISSUES TO DEAL WITH IN THE
SHORTER TERM...SO WILL NOT EXPLICITLY INTRODUCE FROST/FREEZE
CONCERNS IN THE FORECAST PRODUCTS JUST YET. HOWEVER...ITS CERTAINLY
NOT OUT OF THE QUESTION THAT AT LEAST ONE NIGHT MID-LATE NEXT
WEEK COULD REQUIRE A FROST/FREEZE HEADLINE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1219 PM CDT SUN APR 28 2013

EXPECT VFR CONDITIONS DURING THE FORECAST PERIOD. A SURFACE TROUGH
MOVING EAST ACROSS THE REGION WILL SWITCH WINDS FROM SOUTH TO
SOUTHWEST AND EVENTUALLY TO THE NORTH LATER THIS AFTERNOON AND
INTO TONIGHT. SPEEDS SHOULD RANGE IN THE 10-15 KT RANGE. JUST A VERY
SMALL CHANCE FOR ANY CONVECTION TO DEVELOP ALONG THIS TROUGH LATE
THIS AFTERNOON AND WILL NOT PUT IN THE TAF BUT WILL CONTINUE TO MONITOR.

&&

.FIRE WEATHER...
ISSUED AT 515 AM CDT SUN APR 28 2013

FOR TODAY...THE DRY LINE STILL LOOKS LIKE IT WILL BE ON ITS WAY
EAST...BUT WILL STALL IN OUR CWA BEFORE A COLD FRONT MAKES ITS WAY
SOUTH ACROSS THE CWA...COMING FROM THE NORTHERN PLAINS. WITH
LOWERING DEWPOINTS FOR MUCH OF THE CWA...ALONG WITH THE POTENTIAL
FOR COMPRESSIONAL WARMING AND VERY WARM 850 MB TEMPERATURES...I
HAVE INCREASED HIGH TEMPERATURES SIGNIFICANTLY...WELL INTO THE MID
80S. RELATIVE HUMIDITY SHOULD BE SOLIDLY DRY FOR ITS PART TOWARD
CRITICAL FIRE WEATHER...BUT THE WINDS WILL BE LACKING A BIT...WITH
THE MOST POTENTIAL FOR FIRE ISSUES COMING FROM THE GUSTS AS THE
COLD FRONT MAKES ITS WAY TOWARD THE NORTHWESTERN CWA BY MID-LATE
AFTERNOON.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

UPDATE...HEINLEIN
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...EWALD
FIRE WEATHER...HEINLEIN







AREA FORECAST DISCUSSION

NWS BUFFALO NY

 317 PM EDT SUN APR 28 2013

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL LIFT NORTHEAST OUT OF THE OHIO
VALLEY AND BRING SHOWERS TO WESTERN NEW YORK THROUGH THIS
EVENING. SCATTERED SHOWERS WILL LINGER LATE TONIGHT AND INTO
MONDAY. AFTER THIS...A PERSISTENT SOUTHERLY FLOW WILL BRING FAIR
AND WARM WEATHER WHICH WILL LAST THROUGH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
A CLOSED UPPER LEVEL LOW ACROSS INDIANA WILL SLOWLY MOVE TO THE
EAST THROUGH THIS EVENING. ASSOCIATED WITH THIS IS A LOW LEVEL JET
OF AROUND 40 KNOTS...WITH A STEADY AREA OF SHOWERS ACROSS
NORTHEASTERN OHIO AND WESTERN PENNSYLVANIA WHICH APPEARS TO BE
ASSOCIATED WITH THE LEADING EDGE OF THIS LOW LEVEL JET. THIS AREA OF
SHOWERS WILL CONTINUE TO GRADUALLY SPREAD INTO WESTERN NEW YORK LATE
THIS AFTERNOON THROUGH THIS EVENING. ITS PROGRESS MAY BE A BIT
SLOWER THAN PURE EXTRAPOLATION DUE TO DRYING FROM DOWNSLOPING. THIS
IS WELL CAPTURED BY THE HRRR AND MOST OTHER GUIDANCE...AND THUS HAVE
HIGH CONFIDENCE THAT THIS WILL BRING A 2-3 HOUR PERIOD OF SHOWERS TO
MOST LOCATIONS WEST OF ROCHESTER. AFTER THIS...THIS MOISTURE WILL BE
STRETCHED OUT CAUSING IT TO FALL APART AS IT APPROACHES THE EASTERN
LAKE ONTARIO REGION.

UNTIL THIS REACHES YOUR LOCATION...IT WILL CONTINUE TO BE WARM AND A BIT
BREEZY. TEMPERATURES ARE IN THE LOWER TO MID 70S IN MANY
LOCATIONS...EXPECT ABOUT 10 DEGREES COOLER IN THE SOUTHERN TIER WERE
CLOUDS CAME IN EARLY. EXPECT THE ONSET OF SHOWERS TO CAUSE A BRIEF
PERIOD OF WIND GUSTS TO 35 MPH AND A QUICK DROP IN TEMPERATURES BOTH
DUE TO EVAPORATIONAL COOLING.

AFTER THIS INITIAL ROUND OF SHOWERS MOVES THROUGH...PRECIPITATION
IS EXPECTED TO BE MUCH MORE HIT OR MISS. THIS CAN BE SEEN UPSTREAM
ON RADAR AS WELL...WITH SHOWERS BEHIND IT QUITE SCATTERED IN
NATURE. WITH THE UPPER TROF APPROACHING A SHOWER CANNOT BE RULED OUT
LATE TONIGHT...BUT EXPECT COVERAGE SOMEWHAT SPARSE. ALSO...THERE
WILL BE A LIMITED AMOUNT OF ELEVATED CAPE...WITH AN ISOLATED
THUNDERSTORM NOT COMPLETELY OUT OF THE QUESTION. FOR NOW...WILL WAIT
FOR UPSTREAM LIGHTNING STRIKES BEFORE ADDING THIS INTO THE FORECAST
GIVEN THE MARGINAL NATURE.

TEMPERATURES WILL DROP TONIGHT MAINLY BECAUSE OF EVAPORATIONAL
COOLING RATHER THAN RADIATIONAL COOLING DUE TO PERSISTENT WINDS
AND CLOUD COVER. LOWS WILL RANGE FROM THE UPPER 40S TO LOWER 50S.

ON MONDAY...THE UPPER LOW WILL CONTINUE TO OPEN UP AND LIFT
NORTHWARD. EXPECT A CONTINUING CHANCE FOR SHOWERS IN THE
MORNING...WITH THESE TAPERING OFF FROM WEST TO EAST DURING THE
AFTERNOON HOURS. TEMPERATURES WILL REMAIN ON THE WARM SIDE...WITH
HIGHS MAINLY IN THE 60S. IT COULD BE LOCALLY WARMER IF THE SUN
BREAKS OUT...BUT AT THIS TIME EXPECT THE UPPER LOW TO KEEP SKIES
CLOUDY FOR THE MAJORITY OF THE DAY.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
THE SURFACE SURFACE LOW WILL LOSE ALMOST ALL INDICATIONS BY MONDAY
NIGHT...ALL THAT REMAINS WILL BE A WEAK TROUGH ALOFT...A 25-35 KNOT
JET AT 850MB AND EXTENDED BUT WEAK CONVERGENCE IN THE LOWER LEVELS.
PRECIPITATION WILL END FROM WEST TO EAST ALTHOUGH THERE WILL BE
LINGERING CHANCE FOR SHOWER ON TUESDAY WITH DAYTIME HEATING.

HIGH PRESSURE AT THE SURFACE WILL REMAIN ANCHORED OFF THE NEW
ENGLAND COAST TUESDAY AND WEDNESDAY. AT THE SAME TIME...A RIDGE OF
HIGH PRESSURE ALOFT WILL STRENGTHEN ACROSS THE OHIO VALLEY AND
EASTERN GREAT LAKES IN RESPONSE TO A TROUGH THAT WILL BE DIGGING
INTO THE UPPER MIDWEST AND PLAINS STATES. THE HIGH SHOULD KEEP US
DRY THROUGH THIS PERIOD...ALTHOUGH WE MAY SEE A FAIR AMOUNT OF
CLOUDS AS A PERSISTENT SOUTH TO SOUTHEAST FLOW AT THE SURFACE TAPS
INTO ATLANTIC MOISTURE. THE REGION WILL ENTER A WARMER PHASE WITH
HIGH TEMPERATURES ON TUESDAY IN THE LOWER TO MID 70S...AND MID TO
UPPER 70S ON WEDNESDAY AS 850MB TEMPS RISE TO A +12C TO +14C RANGE.
SEASONABLY MILD TEMPERATURES WILL BE THE RULE TUESDAY NIGHT AND
WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE GFS AND ECMWF REMAIN IN GOOD AGREEMENT REGARDING THE POSITION
OF THE OMEGA BLOCK THAT WILL BE IN PLACE ACROSS THE EASTERN TWO
THIRDS OF THE NATION DURING THIS PERIOD. SINCE THE RIDGE OF THE
BLOCKING PATTERN IS EXPECTED TO STAY IN PLACE OVER NEW YORK STATE
AND PA...THE MOISTURE ASSOCIATED WITH THE MIDWEST CLOSED LOW SHOULD
STAY WELL TO OUR WEST. THE RIDGE WILL ALSO RESULT IN AN INCREASE IN
SUNSHINE. THIS SHOULD HELP DAYTIME TEMPERATURES HOLD IN THE LOWER
AND MID 70S.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
ALL TAF SITES WILL START OFF VFR AT 18Z. AN AREA OF RAIN SHOWERS
IS SLOWLY APPROACHING FROM THE SOUTHWEST...AND THIS WILL SLOWLY
MOVE INTO WESTERN NEW YORK THROUGH EARLY EVENING. THIS WILL BRING
A 2-3 HOUR PERIOD OF SHOWERS TO BUF/JHW/IAG/ROC...BUT WITH THE
SOUTHERLY DOWNSLOPE FLOW EXPECT CIGS AND VSBY TO REMAIN IN THE VFR
CATEGORY.

AFTER THIS EXPECT MORE HIT OR MISS SHOWERS. THESE WILL BE QUITE
SCATTERED IN NATURE...BUT COULD POTENTIALLY BRING BRIEF PERIOD OF MODERATE
TO HEAVY RAINFALL. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT. OTHERWISE...
EXPECT MAINLY VFR CONDITIONS TONIGHT...EXPECT FOR JHW WHERE THE
SOUTHERLY FLOW DOES NOT DOWNSLOPE LIKE THE OTHER TAF LOCATIONS.
THE RAIN SHOWERS WILL BE SUPPORTED BY A LOW LEVEL JET...WHICH WILL
PRODUCE SOME LOW LEVEL WIND SHEAR TONIGHT WITH 40-45 KNOT
SOUTHERLY WINDS AT 2K FEET.

FOR MONDAY...EXPECT THE MORNING TO MAINLY BE MVFR IN CIGS AS THE
FLOW BECOMES MORE SSW. SCATTERED SHOWERS WILL LINGER IN THE
MORNING...THEN TAPER OFF DURING THE AFTERNOON WITH GENERALLY
IMPROVING CONDITIONS.

OUTLOOK...
MONDAY NIGHT AND TUESDAY...MAINLY VFR. A CHANCE OF SHOWERS.
TUESDAY NIGHT THROUGH FRIDAY...VFR.

&&

.MARINE...
SOUTH TO SOUTHEAST WINDS WILL INCREASE THROUGH THIS EVENING AS THE
PRESSURE GRADIENT INCREASES ACROSS THE LOWER LAKES. WINDS MAY
APPROACH SMALL CRAFT ADVISORY CRITERIA FOR A TIME LATE TONIGHT AND
EARLY MONDAY...BUT OFFSHORE WINDS WILL KEEP THE GREATER WAVE
ACTION IN CANADIAN WATERS.

RELATIVELY LIGHT SOUTH TO SOUTHEAST WINDS ARE THEN EXPECTED TO
PERSIST FROM TUESDAY THROUGH THE END OF THE WEEK.

&&

.FIRE WEATHER...
DRIER AIR ALOFT HAS MIXED DOWN...RESULTING IN RELATIVE HUMIDITY
DOWN TO 25 PERCENT IN SOME LOCATIONS. WINDS WILL BE BREEZY THROUGH
MID TO LATE AFTERNOON OR SO...WITH A FEW GUSTS TO 25 MPH. RAIN FROM
A COUPLE DAYS AGO PROVIDED SOME WETTING...WHICH WILL HELP MITIGATE
IMPACTS OF THESE DRY CONDITIONS TO SOME DEGREE.

THESE CONDITIONS WILL BE SHORT-LIVED AS RAIN SHOWERS MOVE INTO
WESTERN PORTIONS OF THE SOUTHERN TIER. THESE WILL MOVE NORTHEAST
AND REACH ROCHESTER JUST BEFORE SUNSET.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL
MARINE...APFFEL/WCH
FIRE WEATHER...APFFEL






AREA FORECAST DISCUSSION

NWS BUFFALO NY

 203 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT OFF THE EAST COAST TODAY WITH
SOUTHERLY BREEZES PUSHING TEMPERATURES WELL ABOVE AVERAGE. A WEAK
AREA OF LOW PRESSURE WILL LIFT NORTHEAST OUT OF THE OHIO VALLEY AND
SPREAD SHOWERS INTO WESTERN NEW YORK LATE THIS AFTERNOON THEN ACROSS
THE REST OF THE AREA TONIGHT. OCCASIONAL SHOWERS WILL LAST THROUGH
MONDAY BEFORE DRY WEATHER RETURNS TUESDAY AND LASTS THROUGH NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
A CLOSED UPPER LEVEL LOW ACROSS INDIANA WILL SLOWLY MOVE TO THE
EAST THROUGH THIS EVENING. ASSOCIATED WITH THIS IS A LOW LEVEL JET
OF AROUND 40 KNOTS...WITH A STEADY AREA OF SHOWERS ACROSS
NORTHEASTERN OHIO AND WESTERN PENNSYLVANIA WHICH APPEARS TO BE
ASSOCIATED WITH THE LEADING EDGE OF THIS LOW LEVEL JET. THIS AREA
OF SHOWERS WILL CONTINUE TO GRADUALLY SPREAD NORTHEAST AND INTO
WESTERN NEW YORK DURING THE AFTERNOON HOURS. ITS PROGRESS MAY BE A
BIT SLOWER THAN PURE EXTRAPOLATION DUE TO DRYING FROM DOWNSLOPING.
THIS IS WELL CAPTURED BY THE HRRR AND MOST OTHER GUIDANCE...AND
THUS HAVE HIGH CONFIDENCE THAT THIS WILL BRING A 2-3 HOUR PERIOD
OF SHOWERS TO MOST LOCATIONS WEST OF ROCHESTER THROUGH EARLY
EVENING. AFTER THIS IT IS EXPECTED TO SHEAR AND DRY OUT LATE THIS EVENING.

UNTIL THIS REACHES US...IT WILL CONTINUE TO BE WARM AND A BIT
BREEZY. TEMPERATURES ARE IN THE LOWER TO MID 70S IN MANY
LOCATIONS...EXPECT ABOUT 10 DEGREES COOLER IN THE SOUTHERN TIER
WERE CLOUDS CAME IN EARLY. EXPECT THE ONSET OF SHOWERS TO CAUSE A
SIGNIFICANT AND QUICK DROP IN SURFACE TEMPERATURES WHEN IT STARTS.

AFTER THIS INITIAL ROUND OF SHOWERS MOVES THROUGH...PRECIPITATION
IS EXPECTED TO BE MUCH MORE HIT OR MISS. THIS CAN BE SEEN UPSTREAM
ON RADAR AS WELL...WITH SHOWERS BEHIND IT QUITE SCATTERED IN
NATURE. WITH THE UPPER TROF APPROACHING A SHOWER CANNOT BE RULED
OUT LATE TONIGHT...BUT EXPECT COVERAGE TO BE QUITE SPARSE.
ALSO...THERE WILL BE A LIMITED AMOUNT OF ELEVATED CAPE...WITH AN
ISOLATED THUNDERSTORM NOT COMPLETELY OUT OF THE QUESTION. FOR
NOW...WILL WAIT FOR UPSTREAM LIGHTNING STRIKES BEFORE ADDING THIS
INTO THE FORECAST GIVEN THE MARGINAL NATURE.

TEMPERATURES WILL DROP TONIGHT MAINLY BECAUSE OF EVAPORATIONAL
COOLING RATHER THAN RADIATIONAL COOLING DUE TO PERSISTENT WINDS
AND CLOUD COVER. LOWS WILL RANGE FROM THE UPPER 40S TO LOWER 50S.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
SURFACE LOW PRESSURE MOVING NORTH FROM THE LOWER OHIO VALLEY WILL
CONTINUE TO WEAKEN ON MONDAY AS THE ASSOCIATED UPPER LEVEL TROUGH
WEAKENS AS IT TRACKS EAST ACROSS NEW YORK AND PA. AS THE UPPER LEVEL
TROUGH INTERACTS WITH LOW LEVEL MOISTURE THAT WILL BE TRANSPORTED
NORTH WITH A MODEST LOW LEVEL JET...ONGOING SHOWERS WILL MOVE EAST
ACROSS THE AREA. BECAUSE THE PRIMARY SOURCES LIFT WILL BE MOVING
EAST WHILE WEAKENING...WILL SHOW A DIMINISHING TREND IN THE PROB OF
PCPN AS THE DAY WEARS ON. THE SHOWERS WILL CONTINUE TO TAPER OFF
FROM WEST TO EAST MONDAY NIGHT AS THE WEAKENING TROUGH SLIDES OFF
THE NEW ENGLAND COAST. THIS SYSTEM DOES NOT APPEAR AS IF IT WILL BE
A BIG RAIN MAKER...PRODUCING ONLY ABOUT ONE OR TWO TENTHS OF AN INCH
OR RAINFALL.

CLOUDS AND PASSING SHOWERS WILL KEEP TEMPERATURES COOLER ON
MONDAY...WITH READINGS EXPECTED TO GENERALLY RANGE FROM THE UPPER
50S TO MID 60S.

HIGH PRESSURE AT THE SURFACE WILL REMAIN ANCHORED OFF THE NEW
ENGLAND COAST TUESDAY AND WEDNESDAY. AT THE SAME TIME...A RIDGE OF
HIGH PRESSURE ALOFT WILL STRENGTHEN ACROSS THE OHIO VALLEY AND
EASTERN GREAT LAKES IN RESPONSE TO A TROUGH THAT WILL BE DIGGING
INTO THE UPPER MIDWEST AND PLAINS STATES. THE HIGH SHOULD KEEP US
DRY THROUGH THIS PERIOD...ALTHOUGH WE MAY SEE A FAIR AMOUNT OF
CLOUDS AS A PERSISTENT SOUTH TO SOUTHEAST FLOW AT THE SURFACE TAPS
INTO ATLANTIC MOISTURE. HIGH TEMPERATURES ON TUESDAY WILL RANGE FROM
THE MID 60S TO LOWER 70S ON TUESDAY...WITH A SLIGHT MODERATION
EXPECTED ON WEDNESDAY. SEASONABLY MILD TEMPERATURES WILL BE THE RULE
TUESDAY NIGHT AND WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
THE GFS AND ECMWF ARE NOW IN GOOD AGREEMENT REGARDING THE POSITION
OF THE OMEGA BLOCK THAT WILL BE IN PLACE ACROSS THE EASTERN TWO
THIRDS OF THE NATION DURING THIS PERIOD. SINCE THE RIDGE OF THE
BLOCKING PATTERN IS EXPECTED TO REMAIN IN PLACE OVER NEW YORK STATE AND
PA...THE MOISTURE THAT WILL BE ASSOCIATED WITH THE MIDWEST CLOSED
LOW SHOULD STAY WELL TO OUR WEST. THE RIDGE WILL ALSO RESULT IN AN
INCREASE IN SUNSHINE. THIS SHOULD HELP DAYTIME TEMPERATURES TO WARM
INTO THE LOWER AND MID 70S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
ALL TAF SITES WILL START OFF VFR AT 18Z. AN AREA OF RAIN SHOWERS
IS SLOWLY APPROACHING FROM THE SOUTHWEST...AND THIS WILL SLOWLY
MOVE INTO WESTERN NEW YORK THROUGH EARLY EVENING. THIS WILL BRING
A 2-3 HOUR PERIOD OF SHOWERS TO BUF/JHW/IAG/ROC...BUT WITH THE
SOUTHERLY DOWNSLOPE FLOW EXPECT CIGS AND VSBY TO REMAIN IN THE VFR
CATEGORY.

AFTER THIS EXPECT MORE HIT OR MISS SHOWERS. THESE WILL BE QUITE
SCATTERED IN NATURE...BUT COULD POTENTIALLY BRING BRIEF PERIOD OF MODERATE
TO HEAVY RAINFALL. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT. OTHERWISE...EXPECT
MAINLY VFR CONDITIONS TONIGHT...EXPECT FOR JHW WHERE THE SOUTHERLY
FLOW DOES NOT DOWNSLOPE LIKE THE OTHER TAF LOCATIONS. THE RAIN
SHOWERS WILL BE SUPPORTED BY A LOW LEVEL JET...WHICH WILL PRODUCE
SOME LOW LEVEL WIND SHEAR TONIGHT WITH 40-45 KNOT SOUTHERLY WINDS
AT 2K FEET.

FOR MONDAY...EXPECT THE MORNING TO MAINLY BE MVFR IN CIGS AS THE
FLOW BECOMES MORE SSW. SCATTERED SHOWERS WILL LINGER IN THE
MORNING...THEN TAPER OFF DURING THE AFTERNOON WITH GENERALLY
IMPROVING CONDITIONS.

OUTLOOK...
MONDAY NIGHT AND TUESDAY...MAINLY VFR. A CHANCE OF SHOWERS.
TUESDAY NIGHT THROUGH FRIDAY...VFR.

&&

.MARINE...
SOUTH TO SOUTHEAST WINDS WILL INCREASE THROUGH THIS EVENING AS THE
PRESSURE GRADIENT INCREASES ACROSS THE LOWER LAKES. WINDS MAY
APPROACH SMALL CRAFT ADVISORY CRITERIA FOR A TIME LATE TONIGHT AND
EARLY MONDAY...BUT OFFSHORE WINDS WILL KEEP THE GREATER WAVE
ACTION IN CANADIAN WATERS.

RELATIVELY LIGHT SOUTH TO SOUTHEAST WINDS ARE THEN EXPECTED TO
PERSIST FROM TUESDAY THROUGH THE END OF THE WEEK.

&&

.FIRE WEATHER...
DRIER AIR ALOFT HAS MIXED DOWN IN SOME LOCATIONS...RESULTING IN
RELATIVE HUMIDITY DOWN TO 25 PERCENT IN SOME LOCATIONS. WINDS WILL
BE BREEZY THROUGH MID-AFTERNOON OR SO...WITH A FEW GUSTS TO 25 MPH.
RAIN FROM A COUPLE DAYS AGO PROVIDED SOME WETTING...WHICH WILL
HELP MITIGATE IMPACTS OF THESE DRY CONDITIONS TO SOME DEGREE.

THESE CONDITIONS WILL BE SHORT-LIVED AS RAIN SHOWERS ARE
APPROACHING FROM THE SOUTHWEST. THESE WILL MOVE INTO WESTERN
PORTIONS OF THE SOUTHERN TIER THROUGH MID-AFTERNOON...AND REACH
ROCHESTER JUST BEFORE SUNSET.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...TJP
LONG TERM...TJP
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
FIRE WEATHER...APFFEL





AREA FORECAST DISCUSSION

NWS BURLINGTON VT

 123 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE OVER THE REGION FOR
THE NEXT UPCOMING SEVERAL DAYS. THERE WILL BE A CHANCE FOR
PRECIPITATION ON MONDAY AND TUESDAY FOR NORTHERN NEW YORK...AS A
TROUGH OF LOW PRESSURE ATTEMPTS TO PUSH THROUGH THE AREA...OTHERWISE
DRY AND WARM CONDITIONS WILL PERSIST.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1023 AM EDT SUNDAY...MINOR ADJUSTMENTS TO SFC DEWPOINTS TO
LOWER VALUES THROUGH THE AFTERNOON HOURS BEFORE RECOVERY LATER
THIS EVENING. RAP PROFILES SHOW DEPTH OF PBL TO AROUND 750 MB
TODAY SO THIS SHOULD MIX DOWN DRIER AIR ACCORDINGLY. OTW INHERITED
FORECAST IN GREAT SHAPE WITH SUNNY/MILD CONDITIONS EXPECTED. HAVE
A GREAT DAY.

PREVIOUS DISCUSSION...A NICE WARM DAY ON TAP FOR THE ENTIRE NORTH
COUNTRY AS HIGH PRESSURE REMAINS OVER THE NEW ENGLAND REGION. TO
OUR NORTH...CLDS FROM WK UPPER TROUGH PERSIST OVER QUEBEC...AND TO
OUR SOUTH LOW PRESSURE OVER THE LOWER TENNESSEE VALLEY. MDLS BEGIN
TO SHIFT RIDGE EASTWARD DURING THE COURSE OF THE DAY ALLOWING FOR
SOUTHERLY FLOW/WAA TO WORK INTO N NY. BUFKIT PROFILES DO SHOW VEIL
OF MID-LEVEL MOISTURE STREAMING NORTH ALONG THE WEST SIDE OF THE
SFC RIDGE BY THE AFTNOON...FUNNELED UP FROM SOUTHERN SYSTEM. WILL
GO FORTH AND BRING SOME CLD COVER FOR N NY DURING THIS TIME FRAME.
THE RESULT OF THESE EXPECTED CLDS WILL DAMPEN SUNSHINE AND THUS
HIGHS IN THAT AREA. OVERALL MID/UPPER 60S IN HIR ELEV AND UP TO
L70S IN VALLEY LOCALES WITH NO PRECIP EXPECTED TDY. GOING INTO
TNGT...SOUTHERLY FETCH PERSISTS THRU PERIOD ALLOWING FOR ABV
NORMAL LOWS RANGING FROM THE M30S FOR DACKS/NE VT TO THE 40S
ELSEWHERE. REMNANTS OF LOW TO OUR SOUTH WILL BE WORKING INTO THE
OHIO VALLEY OVERNGT KEEPING HIGHER CHANCE FOR CLDS OVER N NY AND
LESS FOR CVLY EASTWARD. SOME --RW WILL BEGIN TO DEVELOP OVER SLV
BY 12Z MONDAY AHEAD OF SFC LOW.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
AS OF 342 AM EDT SUNDAY...THE WX FOCUS FOR MONDAY AND TUESDAY
CONTINUES TO BE THE STRONG SFC RIDGE OVER CENTRAL AND EASTERN NEW
ENGLAND. THE REMNANTS OF SFC LOW FROM THE OHIO VALLEY WILL PUSH
INTO WESTERN NY DURING THE DAY. HAVE CONTINUED TREND OF LIGHT -RW
OVER N NY WITH NO EASTWARD PUSH PAST THE CVLY. PRECIP BEGINS TO
WANE GOING INTO THE EVENING/OVERNGT HRS MONDAY AS UPPER/SFC RIDGE
SHIFT BACK WESTWARD. SOME LINGERING --RW FOR WESTERN PORTIONS OF
SLV TUES MORNING ON THE WEST SIDE OF RIDGE...W/ STRONG SUBSIDENCE
FOR EASTERN DACKS/CVLY AND VT. HIGHEST TEMPS FOR MONDAY WILL OCCUR
CVLY EASTWARD AWAY FROM CLD COVER INFLUENCE OF OHIO VALLEY LOW.
OVERALL HIGHS WILL BE IN THE 60S FOR MONDAY AND MAINLY L70S FOR
TUESDAY W/ SOME 60S IN DACKS DUE TO CLD COVER.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 317 AM EDT SUNDAY...LITTLE CHANGE IN 00Z NWP GUIDANCE SUITE WITH
RESPECT TO QUIET EXTENDED FCST. PROMINENT MID-TROPOSPHERE OMEGA
BLOCK DEVELOPS ACROSS THE ERN GREAT LAKES INTO SERN ONTARIO/WRN
QUEBEC BRINGING TRANQUIL WEATHER TO THE NORTH COUNTRY THRU
SATURDAY. NO PRECIPITATION FCST. WITH SUBSIDENCE AND MOSTLY CLEAR
SKIES...MODERATELY LARGE DIURNAL TEMPERATURE RANGES ARE FORECAST
WITH HIGHS MAINLY IN THE LOWER 70S AND LOWS IN THE LOW-MID 40S. EXPECT
SLIGHTLY COOLER DAYTIME HIGHS ALONG THE LAKE CHAMPLAIN SHORELINE...PER
WATER TEMP ONLY 40F. FOR OVERNIGHT TEMPS...A FEW MID-UPR 30S
ANTICIPATED IN THE NORMALLY COLDER VALLEYS OF FAR NERN VT AND
WITHIN THE NRN ADIRONDACK REGION.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...VFR CONDITIONS WL PREVAIL AT ALL TAF SITES
THRU 18Z MONDAY...AS SFC HIGH PRES CONTS ACRS OUR FA.
HOWEVER...MID/UPPER LVL MOISTURE WL PRODUCE AN INCREASE IN HIGH
CLOUDS FROM SW TO NE ACRS OUR TAF SITES TONIGHT. A FEW LIGHT
SHOWERS WL BE POSSIBLE BY 12Z MONDAY NEAR KMSS...BUT GIVEN VERY
DRY LLVLS EXPECT MOSTLY VIRGA TO FALL...AND WL JUST MENTION VCSH
ATTM...WITH CIGS BKN AT 5000 FT. SOUTH TO SOUTHWEST WIND AT 5 TO
10 KNTS WL CONT THIS AFTN AND BECM TRRN DRIVEN OVERNIGHT. ON
MONDAY...SOUNDINGS SHOW THE LLVL WIND FIELD INCREASE WITH SFC
GUSTS BTWN 15 AND 20 KNTS POSSIBLE AFT 12Z.

OUTLOOK 18Z MONDAY THROUGH FRIDAY...
18Z MONDAY-12Z TUESDAY...BRIEF INTERVALS OF MVFR POSSIBLE WITH A
FEW RAIN SHOWERS...ESPECIALLY MSS AND SLK.

18Z TUESDAY-18Z FRIDAY...SFC HIGH PRES AND VFR WITH LIGHT WINDS WL
PREVAIL AT ALL TAF SITES.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...JN
NEAR TERM...JMG/JN
SHORT TERM...JN
LONG TERM...BANACOS
AVIATION...TABER










AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 346 PM EDT SUN APR 28 2013

.SYNOPSIS...
HIGH PRESSURE OFF THE NEW ENGLAND COASTLINE WILL LOSE ITS GRIP ON
OUR WEATHER AS DISORGANIZED LOW PRESSURE DEVELOPS ACROSS THE
SOUTHEASTERN UNITED STATES. THIS LOW WILL BRING INCREASING CHANCE
OF SHOWERS TONIGHT THROUGH MONDAY WITH WIDESPREAD SHOWERS AND
ISOLATED THUNDERSTORMS ON MONDAY. THE LOW WILL PUSH OFFSHORE
TUESDAY BUT MAY LINGER AS HIGH PRESSURE BUILDS DOWN FROM THE
NORTH. A TROUGH OF LOW PRESSURE WILL BRING UNSETTLED WEATHER
WEDNESDAY THROUGH FRIDAY AND MAY LINGER INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SUNDAY...TIMING OF PCPN AND EVEN CLOUDINESS
OVERSPREADING THE FORECAST AREA CONTINUES TO REMAIN THE MAIN
ISSUES FOR THE NEAR TERM PERIOD. THE NORTH TO SOUTH MID-LEVEL
RIDGE AXIS REMAINS THE PROBLEM CHILD AS IT HAS BECOME MUCH SLOWER
IN MOVING FURTHER EAST OF THE FORECAST AREA TODAY. IN TURN THIS
HAS ALLOWED A PERSISTENT AND DRIER LOW LEVEL EASTERLY FLOW TO
AFFECT MAINLY THE EASTERN PORTIONS OF THE FA RESULTING IN
BASICALLY PCPN UNABLE TO MAKE ANY PROGRESS EASTWARD TO THE COAST.
MODELS ARE FINALLY IN UNISON...PUSHING THE UPPER RIDGE AXIS OFF
THE CAROLINA COASTS THIS AFTERNOON AND EVENING...AND FINALLY
ALLOWING THE ATM TO MOISTEN UP. LOOK FOR SLOWLY INCREASING POPS
THIS AFTERNOON...REACHING CATEGORICAL AFTER MIDNIGHT ACROSS ALL
LOCATIONS. HAVE INCLUDED ISOLATED CONVECTION OVERNIGHT...DUE TO A
SLOWLY DESTABILIZING ATM AS AN UPPER VORT MOVES TOWARD THE
FA...AND IN ADDITION A WEAK WSW-ENE ORIENTED SFC TROF TO MANIFEST
ITSELF ACROSS THE FA. WILL ONLY INCLUDE ISOLATED AT THIS POINT.
CLOUDS...PCPN...AND AN ONSHORE FLOW WILL LIMIT DECREASING TEMPS
OVERNIGHT. HAVE BASICALLY GONE WITH A MILD NIGHT ADVERTISING
NEARLY WIDESPREAD LOW 60S FOR MINS...WITH A FEW POCKETS OF UPPER
50S.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...HIGH PRESSURE FROM THE SURFACE UP THROUGH
THE MID TO UPPER LEVELS WILL SHIFT EAST AS H5 SHORTWAVE MOVES
CLOSER TOWARD THE LOCAL AREA. THIS WILL PRODUCE A DEEP RETURN FLOW
OF WARM MOIST AIR UP THROUGH THE SOUTHEAST THROUGH MONDAY. DECENT
MID TO UPPER LEVEL DYNAMICS WILL COME INTO PLAY ON MONDAY COMBINED
WITH HEATING AND LOCAL EFFECTS SUCH AS SEA BREEZE CONVERGENCE AND
ANY OTHER LOCAL BOUNDARIES THAT DEVELOP. SHOULD TAP INTO BOTH GULF
AND ATLANTIC MOISTURE AS LLJ INCREASES UP AROUND 30 TO 35 KTS.
DEWPOINT TEMPS WILL REACH AROUND 60 WITH PCP WATER VALUES REACHING
UP AROUND 1.5 INCHES. SIGNIFICANT CLOUD COVER ON MONDAY MAY LIMIT
BEST THUNDERSTORM POTENTIAL...BUT SHOULD SEE WIDESPREAD SHOWERS
AND ISOLATED TSTMS THROUGH THE DAY.

MID TO UPPER TROUGH AXIS WILL MOVE OFF SHORE OVERNIGHT MONDAY INTO
TUES WITH INCREASING SUBSIDENCE ON BACK END. HIGH PRESSURE WILL
BUILD DOWN FROM THE NORTH WHILE LOW PRESSURE OVER THE GULF
MAINTAINS MORE UNSETTLED WEATHER TO THE SOUTH AND COASTAL
TROUGH/WEAK LOW EXTENDS UP THROUGH THE LOCAL WATERS TO THE EAST.
OVERALL EXPECT A FAIR AMOUNT OF LINGERING MOISTURE. NAM PUSHES THE
COASTAL TROUGH BACK INLAND WHILE THE GFS SHOWS HIGH PRESSURE
BUILDING DOWN WITH A COOLER NORTHERLY FLOW DEVELOPING. EITHER
WAY...EXPECT SUNSHINE ON TUESDAY WILL LEAD TO DAYTIME HEATING AND
GREATER INSTABILITY. THEREFORE WOULD EXPECT THIS TO HELP PRODUCE
MORE CU BUILDUP AND POSSIBLE SHOWERS ON TUES.

WAA WILL LEAD TO TEMPS REACHING INTO THE 70S ON MONDAY BUT THIS
WILL BE HAMPERED BY CLOUDS AND SHOWER ACTIVITY AND THEREFORE DO
NOT EXPECT MUCH MORE THAN LOWER 70S. TUES WILL HAVE GREATER AMOUNT
OF SUNSHINE LEADING TO TEMPS IN THE MID 70S MOST PLACES. SOME
UNCERTAINTY EXISTS AS TO HOW FAR HIGH PRESSURE WILL BUILD IN
POSSIBLY PRODUCING A COOLER NORTHERLY FLOW. OVERNIGHT LOWS WILL BE
CLOSE TO 60 BOTH NIGHTS WITH CLOUDS AND INCREASED MOISTURE
PRESENT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...COMPLICATED AND HIGHLY AMPLIFIED PATTERN TO
WREAK HAVOC ON THE EXTENDED FORECAST. WHILE BASIC SYNOPTIC REGIME
IS AGREED UPON BY MOST GUIDANCE...MINOR TEMPORAL AND SPATIAL
DIFFERENCES LEAD TO SIGNIFICANT VARIATIONS IN THE SENSIBLE
WEATHER.

SOME AGREEMENT INITIALLY IN THAT WEAK LOW/TROUGH WILL ENHANCE SOME
ISENTROPIC LIFT ABOVE A SURFACE HIGH RIDGING DOWN THE COAST. THIS
WILL SUPPORT SOME SHOWERS WED/THU...BUT OVERALL COVERAGE AND
INTENSITY WILL BE LIGHT. HAVE DROPPED POP FROM INHERITED TO SCHC THU
THANKS TO THE DRIER SOLUTION NOW SUPPORTED BY THE FAVORED ECMWF.
WILL NOT GO DRY AS SOME LOW LEVEL MOISTURE REMAINS IN FORECAST
PROFILES...BUT THURSDAY MAY TURN OUT TO JUST BE CLOUDY. TEMPS
WED-THU WILL BE SLIGHTLY BELOW CLIMO FOR HIGHS AND SLIGHTLY ABOVE
FOR LOWS.

PATTERN BECOMES MORE COMPLEX THEREAFTER AS OMEGA BLOCK DEVELOPS
ACROSS THE EXTREME EASTERN CONUS/WESTERN ATLANTIC BETWEEN DEEP 5H
CUTOFF LOWS ON EITHER SIDE. EPD FROM WPC THIS MORNING SAYS IT BEST,
`THE ATMOSPHERE WILL HIT THE BRAKES HARD AND TEMPORARILY PAUSE THE
UPPER LEVEL FLOW.` THIS OCCURS AS FLOW BECOMES BLOCKED (HENCE THE
TERM) FORCING SYSTEMS TO STALL OR EVEN RETROGRADE AS IS THE PROGGED
CASE FOR THE MIDWEST SYSTEM. CURRENT ECMWF IS A REASONABLE
COMPROMISE BETWEEN THE GFS/CMC SOLUTIONS...AND WILL BE RELIED UPON
HEAVILY FOR THIS PACKAGE. WHILE MUCH UNCERTAINTY STILL EXISTS IN THE
EXACT PLACEMENT OF THESE FEATURES...TREND HAS BEEN FOR A SLIGHTLY
STRONGER RIDGE...AND HENCE A MORE WESTWARD BLOCK OF THE
UPPER/SURFACE SYSTEMS. THIS COULD VERY WELL MEAN A WARM AND DRY
WEEKEND AS COLD FRONT GETS HUNG UP WELL WEST OF THE REGION...ALBEIT
WITH STILL NE COOLING SURFACE WIND. FOR NOW...WILL CONTINUE WITH
SCHC FOR THE WKND WITH SLIGHTLY BELOW NORMAL TEMPS...BUT MAY HAVE TO
TREND WARMER AND DRIER AS THE FORECAST EVOLVES.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...LIGHT RADAR RETURNS OVER THE INLAND PORTIONS OF THE
FORECAST AREA HAS PRODUCED BRIEF PERIODS OF -RA AT KFLO THIS
MORNING AND LBT THIS AFTERNOON. CURRENTLY VFR AT ALL TERMS WITH
MAINLY MID-LEVEL CIGS AROUND 10KFT AND SCT LOWER CLOUDS AROUND 5K
FT ESPECIALLY INLAND WHERE VIRGA IS LIKELY OCCURRING. EXPECT BRIEF
PERIODS OF -RA TO CONTINUE AT KFLO/KLBT THIS AFTERNOON. ALONG THE
COAST...THE DRIER LOW LEVELS COMPARED TO INLAND...WILL PREVENT
PCPN FROM REACHING THE SFC UNTIL AFTER 00Z. RAIN CHANCES INCREASE
TONIGHT AS THE SHORTWAVE TO OUR WEST MOVES CLOSER TO THE
CAROLINAS. HRRR INDICATES SHOWER ACTIVITY AND COVERAGE WILL
INCREASE OVERNIGHT INTO MON. MVFR CIGS...WITH IFR LATE...CIGS
WILL LIKELY DEVELOP AS THE COLUMN SATURATES AND RAINFALL
PERSISTS... BEGINNING AT KFLO/KLBT. EXPECT LIGHT STRATIFORM RAINS
THIS AFTERNOON THROUGH THE OVERNITE...WITH POCKETS OF MODERATE RW.
CONVECTIVE TYPE PCPN WILL BECOME MORE DOMINANT AFTER DAYBREAK MON
AS THE ATM DESTABILIZES.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
THROUGH MONDAY NIGHT. CHANCE OF SHOWERS TUESDAY AND WEDNESDAY.
SLIGHT RAIN CHANCES LINGER FOR MUCH OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SUNDAY...THE NOSE OF SFC HIGH PRESSURE HAS FINALLY
BEGUN TO GET SHUNTED EASTWARD...AND SHOULD BE OFF THE CAROLINA
COASTS EARLY THIS EVENING. THIS WILL ALLOW A VEERING WIND TO
OCCUR...WITH AN ENE-E WIND LATE THIS AFTERNOON...BECOMING ESE-SE
THIS EVENING...AND FURTHER VEERING TO MORE OF A SOUTHERLY
DIRECTION DURING THE PRE-DAWN HRS OF MON. SOMEWHAT RELAXED SFC PG
PROGGED THIS AFTERNOON AND EVENING...AND FINALLY TIGHTENS-SOME
AFTER MIDNIGHT. WIND SPEEDS OF 8-12 KT EARLY THIS EVENING...WILL
INCREASE TO NEARLY A SOLID 15 KT WITH GUSTS AOA 20 KT.

A DECENT FETCH WILL EXIST ALLOWING FOR AN EASTERLY GROUND SWELL AT 2
TO 3 FT EXHIBITING 12-15 SECOND PERIODS TO AFFECT THE LOCAL WATERS.
COMBINED WITH A SLOWLY INCREASING LOCALLY PRODUCED WIND DRIVEN
WAVES...SIGNIFICANT SEAS WILL RANGE BETWEEN 3 TO 4 FT...WITH 5
FOOTERS ALONG THE OUTER WATERS ESPECIALLY OFF CAPE FEAR TO SURF
CITY. WILL BECOME BORDERLINE SCEC CONDITIONS AFTER MIDNIGHT.
STRATIFORM PCPN WILL WEAKEN AND BREAK-UP AS IT MOVES OFF THE
MAINLAND LATE THIS AFTERNOON. HOWEVER...TONIGHT THE PCPN MOVING OFF
THE MAINLAND WILL HAVE BETTER DYNAMICS ALOFT TO WORK WITH AND A
MOISTENING ATM PROFILE...AND THUS WILL NOT DISSIPATE.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...HIGH PRESSURE SHIFTS FARTHER OFF THE COAST
WITH AN INCREASING RETURN FLOW SETTING UP THROUGH MONDAY. EXPECT
SOUTHERLY WINDS UP AROUND 15 KTS THROUGH MONDAY AFTERNOON AS
GRADIENT TIGHTENS. MID TO UPPER TROUGH WILL MOVE THROUGH PRODUCING
FAIRLY WIDESPREAD SHWRS AND ISOLATED THUNDERSTORMS WHICH MAY HELP
TO INCREASE WINDS AND CHURN UP SEAS. OVERALL EXPECT SEAS TO
INCREASE TO 3 TO 5 FT THROUGH MONDAY WITH A STRONG SOUTHERLY PUSH.
SEAS WILL SUBSIDE THROUGH TUESDAY AS GRADIENT RELAXES AND WINDS
DIMINISH TO 10 KTS OR LESS. SEAS WILL DROP TO 2 TO 4 FT BY TUESDAY.

LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...HIGH PRESSURE RIDGING DOWN THE COAST AND A
TROUGH OF LOW PRESSURE STRENGTHENING OFFSHORE WILL CREATE A
GRADUALLY TIGHTENING PRESSURE GRADIENT...AND INCREASING NE WINDS
INTO FRIDAY. THE STRONGEST WINDS WILL BE THURSDAY AFTN INTO FRIDAY
MORNING...WHEN 20-25 KT NE ARE EXPECTED. OTHERWISE WINDS WILL BE
10-15 KTS...VEERING SLIGHTLY TO THE EAST FRIDAY AS GRADIENT RELAXES.
ALTHOUGH A DECENT 10-13 SEC EAST SWELL WILL GRADUALLY DECAY THROUGH
THE PERIOD...WAVES WILL BE PREDOMINANTLY WIND-DRIVEN. SEAS OF 2-4 FT
EARLY WEDNESDAY WILL RISE TO 4-7 FT THURSDAY AND EARLY
FRIDAY...BEFORE FALLING AGAIN FRIDAY. A SMALL CRAFT ADVISORY WILL
LIKELY BE NEEDED ALL OF THURSDAY AND MUCH OF FRIDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...III
AVIATION...DCH/BJR







AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 208 PM EDT SUN APR 28 2013

.SYNOPSIS...
A SERIES OF DISORGANIZED LOW PRESSURE AREAS WILL BRING AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MONDAY. A DRYING TREND
IS EXPECTED DURING THE MIDDLE OF THE WEEK. A BACKDOOR COLD FRONT
WILL DROP SOUTH THROUGH THE AREA WEDNESDAY...AND A SECOND FRONT WILL
APPROACH FROM THE WEST LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...TIMING OF PCPN AND CLOUDINESS OVERSPREADING
THE FORECAST AREA THROUGH TONIGHT ARE THE MAIN PARAMETERS NEEDING
UPDATES. EXTRAPOLATED USING THE LATEST TRENDS/LOOPS OF THE 88D
RADAR MOSAIC AND VISIBLE SATELLITE IMAGERY...AND IN ADDITION THE
LATEST HOURLY HRRR UPDATES. STRATIFORM LIGHT RAIN WILL CONTINUE AS
THE MAIN PCPN TYPE...WITH ISOLATED THUNDER POSSIBLE THIS
AFTERNOON THROUGH TONIGHT ASSOCIATED WITH WEAK DYNAMICS FROM THE
PASSAGE OF THOSE WEAK MID LEVEL VORT LOBES. HAVE ALSO UPDATED QPF
FIELDS TO ACCOUNT FOR THE PCPN TIMING...BUT IN GENERAL HAVE KEPT
THE 24 HR AMOUNTS IN TUNE TO THE PREVIOUS FCST.

PREVIOUS DISCUSSION....................................
AS OF 630 AM SUNDAY...RADAR SHOWS A BATCH OF MAINLY LIGHT RAIN
MOVING THROUGH THE SC SAND HILLS AND APPROACHING FLORENCE. MEASURABLE
RAIN IS REACHING THE GROUND AS SHOWN BY THE .02 INCH HOURLY AMOUNT
JUST MEASURED AT THE KCDN AWOS. MUCH LIKE WE SAW YESTERDAY THIS RAIN
SHOULD LOSE ITS PUNCH AS IT MOVES EASTWARD INTO DRIER LOW LEVELS
EAST OF THE MID AND UPPER LEVEL RIDGE AXIS. THE LATEST FEW HRRR RUNS
SUGGEST WE`LL SEE A BREAK IN PRECIPITATION EVEN ACROSS THE PEE DEE
REGION FROM NOON THROUGH MID AFTERNOON...WITH A MUCH MORE
SUBSTANTIAL BAND OF SHOWERS PUSHING TOWARD THE I-95 CORRIDOR BY
EARLY EVENING. NO CHANGES HAVE BEEN MADE TO TEMPERATURE FORECASTS...
BUT IT WILL BE INTERESTING TO SEE HOW MUCH OPAQUE CLOUD COVER HANGS
AROUND BEYOND NOON IF THERE IS INDEED A SIZABLE BREAK IN
PRECIPITATION. THIS COULD HAVE IMPACTS ON HIGH TEMPERATURE FORECASTS
TOO. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...

SURFACE HIGH PRESSURE STALLED OFF THE NEW ENGLAND COASTLINE
CONTINUES TO FEED HEAVILY MODIFIED BUT STILL QUITE DRY ARCTIC AIR
SOUTHWARD ACROSS THE WESTERN ATLANTIC. THIS FLOW OF AIR IS THEN
ADVECTING INTO THE EASTERN CAROLINAS WHERE IT HAS EATEN UP AT LEAST
THREE EASTWARD-MOVING WAVES OF RAIN OVER THE 24 HOURS. YET ANOTHER
BATCH OF RAIN CURRENTLY ENTERING WESTERN SOUTH CAROLINA WILL LIKELY
FEEL THE EFFECTS OF THIS DRY AIR LATER THIS MORNING. MY FORECAST HAS
RAIN CHANCES HIGHEST WEST OF I-95...WITH VERY LITTLE PRECIPITATION
POTENTIAL DOWN AT THE COAST.

THE UPPER LEVEL PATTERN SHOWS A LOW ACROSS ILLINOIS WITH A SOUTHERN
STREAM RIDGE OVER THE CAROLINAS. WEAK SOUTHERN STREAM DISTURBANCES
ALOFT ARE DAMPING OUT AS THEY MOVE THROUGH THIS RIDGE POSITION IN
THE JET...BUT PLENTY OF GULF MOISTURE BEING LIFTED INTO THE MIDDLE
AND UPPER LEVELS OF THE ATMOSPHERE IS SUPPORTING A BROAD ZONE OF
CLOUDS WITH AREAS OF RAIN ACROSS GEORGIA AND THE WESTERN CAROLINAS.
THE UPPER RIDGE IS EXPECTED TO PUSH OFFSHORE TONIGHT...ALLOWING THE
INCOMING DISTURBANCES AND MOISTURE STREAM TO REACH THE EASTERN
CAROLINAS MORE INTACT. ALSO OF IMPORTANCE ARE TWO JET STREAKS WHICH
TONIGHT MOVE INTO FAVORABLE POSITIONS (FLORIDA PANHANDLE AND
CHESAPEAKE BAY REGION) FOR BOTH TO PROVIDE ADDITIONAL SYNOPTIC LIFT
FOR PRECIPITATION LOCALLY. FOR THIS REASON I HAVE POPS FORECAST AT
100 PERCENT ACROSS THE I-95 CORRIDOR THIS AFTERNOON AND TONIGHT...
WITH RAIN CHANCES FINALLY INCREASING TO 60-70 PERCENT AT THE COAST
LATE TONIGHT.

CLOUDS AND ONSHORE WINDS WILL HELP CONSTRAIN DIURNAL RANGES...WITH
DAYTIME HIGHS 68-73 AND LOWS TONIGHT 58-63.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...MID LEVEL RIDGE TO THE EAST AND TROUGHING TO THE
WEST SETS UP DEEP SOUTHWEST FLOW ALOFT WHICH PUSHES GULF MOISTURE
INTO THE REGION MON/MON NIGHT. MEANWHILE AT THE SURFACE HIGH
PRESSURE OFF THE EASTERN US COAST WILL ADVECT LOW LEVEL ATLANTIC
MOISTURE INTO REGION. DEEP MOISTURE...DIVERGENT FLOW ALOFT...WEAK
COASTAL TROUGH(WHICH MAY OR MAY NOT MOVE ONSHORE)...AND DIURNAL
INSTABILITY SHOULD PRODUCE WIDESPREAD SHOWERS WITH ISOLATED
THUNDERSTORMS. BASED ON FORECAST SOUNDINGS DO NOT THINK UPDRAFTS
WILL BE ALL THAT STRONG SO DO NOT ANTICIPATE MUCH IN THE WAY OF
LIGHTNING...BUT INLAND AREAS WOULD BE MORE FAVORED ESPECIALLY IN THE
AFTERNOON. DO NOT ANTICIPATE ANY SEVERE WEATHER GIVEN LOW CAPE
VALUES...LACK OF ANY JETTING...AND WEAK LAPSE RATES. PRECIPITABLE
WATER VALUES WILL BE ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL SO
HEAVY RAIN COULD BE AN ISSUE.

MID LEVEL SHORTWAVE TROUGH MOVES OFF THE EAST COAST EARLY TUE.
ALTHOUGH THERE REMAINS SOME DISCREPANCY BETWEEN THE GUIDANCE
AGREEMENT ON TUE IS MUCH BETTER THAN IS WAS 24 HOURS AGO. SUBSIDENCE
BEHIND THE EXITING SHORTWAVE AND FROM WEAK MID LEVEL RIDGE BUILDING
IN FROM THE NORTHWEST HELPS DRY THE AREA FOR TUE/TUE NIGHT. LOW
LEVEL MOISTURE COMBINED WITH DIURNAL INSTABILITY COULD GENERATE A
FEW SHOWERS DURING THE AFTERNOON AND EVENING HOURS BUT COVERAGE WILL
BE CONSIDERABLY LESS THAN MON. CLOUDS AND RAIN ON MON WILL KEEP
HIGHS BELOW CLIMO BUT CLEARING EXPECTED ON TUE WILL LEAD TO HIGHS
NEAR CLIMO. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...STILL A LOT OF HAND WRINGING IN THE EXTENDED.
GFS/ECMWF HAVE COME INTO MUCH BETTER AGREEMENT OVER THE LAST DAY OR
SO BUT PITFALLS ABOUND IN THE LONG TERM. BOTH GFS/ECMWF DEVELOP A
REX BLOCK OVER THE EASTERN CONUS WED/THU. THEY DEPICT A MID LEVEL
RIDGE SETTING UP OVER THE GREAT LAKES...OH VALLEY AND MID-ATLANTIC
REGIONS WITH SOUTHERN STREAM 5H LOW STALLING OVER THE CENTRAL GULF
COAST. AT THIS POINT THE PATTERN SLOWLY EVOLVES TO AN OMEGA BLOCK
LATE IN THE WEEK. THE 5H LOW IN THE GULF COAST DRIFTS WEST AND
STARTS TO FILL. AT THE SAME TIME A 5H LOW DIGS SOUTH FROM CANADA
INTO TX AS ANOTHER DROPS SOUTH FROM THE CANADIAN MARITIMES TO THE
WESTERN ATLANTIC. WITH SUCH A COMPLICATED PATTERN ALOFT THE LOCAL
FORECAST BECOMES QUITE TRICKY. CURRENTLY BOTH THE GFS/ECMWF HAVE THE
CAROLINAS IN THE RIDGING PORTION OF THE BLOCK WITH DEEP DRY AIR AND
SUBSIDENCE KEEPING THE REGION NEARLY PRECIP FREE. A SLIGHT SHIFT IN
THE LOCATION OF THE MID LEVEL FEATURES WOULD RESULT IN A DRASTICALLY
DIFFERENT OUTCOME FOR THE LOCAL AREA. GIVEN THE HIGH AMOUNT OF
UNCERTAINTY WILL MAINTAIN THE INHERITED DIURNAL CHANCE POP WITH
TEMPERATURES NEAR TO BELOW CLIMO.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...LIGHT RADAR RETURNS OVER THE INLAND PORTIONS OF THE
FORECAST AREA HAS PRODUCED BRIEF PERIODS OF -RA AT KFLO THIS
MORNING AND LBT THIS AFTERNOON. CURRENTLY VFR AT ALL TERMS WITH
MAINLY MID-LEVEL CIGS AROUND 10KFT AND SCT LOWER CLOUDS AROUND 5K
FT ESPECIALLY INLAND WHERE VIRGA IS LIKELY OCCURRING. EXPECT BRIEF
PERIODS OF -RA TO CONTINUE AT KFLO/KLBT THIS AFTERNOON. ALONG THE
COAST...THE DRIER LOW LEVELS COMPARED TO INLAND...WILL PREVENT
PCPN FROM REACHING THE SFC UNTIL AFTER 00Z. RAIN CHANCES INCREASE
TONIGHT AS THE SHORTWAVE TO OUR WEST MOVES CLOSER TO THE
CAROLINAS. HRRR INDICATES SHOWER ACTIVITY AND COVERAGE WILL
INCREASE OVERNIGHT INTO MON. MVFR CIGS...WITH IFR LATE...CIGS
WILL LIKELY DEVELOP AS THE COLUMN SATURATES AND RAINFALL
PERSISTS... BEGINNING AT KFLO/KLBT. EXPECT LIGHT STRATIFORM RAINS
THIS AFTERNOON THROUGH THE OVERNITE...WITH POCKETS OF MODERATE RW.
CONVECTIVE TYPE PCPN WILL BECOME MORE DOMINANT AFTER DAYBREAK MON
AS THE ATM DESTABILIZES.

EXTENDED OUTLOOK...SHOWERS/ISO TSTMS LIKELY WITH MVFR/IFR POSSIBLE
THROUGH MONDAY NIGHT. CHANCE OF SHOWERS TUESDAY AND WEDNESDAY.
SLIGHT RAIN CHANCES LINGER FOR MUCH OF THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SUNDAY...THE NOSE OF HIGH PRESSURE EXTENDING ACROSS
THE EASTERN CAROLINAS FROM THE NE IS PROGGED TO SLIDE JUST
OFFSHORE TODAY AS A WEAK SFC TROF DEVELOPS OVERNIGHT AND EXTENDS
FROM WSW TO ENE ACROSS THE CAROLINAS...MIMICKING A WARM FRONT.
LOOK FOR WINDS TO VEER FROM ENE-E TODAY TO ESE TO SE TONIGHT.
THE LATEST HRRR AND NAM ILLUSTRATE THIS TREND. OVERALL...THIS WILL
CONTINUE THE ONSHORE TYPE FLOW COVERING A DECENT FETCH. EXPECT 3 TO
4 FOOT SIGNIFICANT SEAS TODAY...WITH 5 FOOTERS OFF CAPE FEAR. A 2
TO 3 FOOT ESE GROUND SWELL EXHIBITING 13 TO 15 SECOND PERIODS WILL
DOMINATE SIGNIFICANT SEAS. TWO TO 3 FOOT WIND DRIVEN WAVES AT 5 TO 7
SECOND PERIODS...COULD PUSH SIGNIFICANT SEAS TO 5 FOOT ACROSS A
LARGER REAL ESTATE AREA OTHER THAN THE WATERS OFF CAPE FEAR. WILL
NEED TO MONITOR. STRATIFORM PCPN WILL WEAKEN AND BREAK-UP AS IT
MOVES OFF THE MAINLAND THIS AFTERNOON. HOWEVER...TONIGHT THE PCPN
MOVING OFF THE MAINLAND WILL HAVE BETTER DYNAMICS ALOFT TO WORK
WITH...AND THUS NOT BREAK UP/DISSIPATE.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SOLID 15 KT SOUTHERLY FLOW EXPECTED ON MON AS
GRADIENT OVER THE WATERS BECOMES PINCHED. MID LEVEL TROUGH MOVES
OFF THE COAST MON NIGHT INTO TUE. EARLY TUE PINCHED GRADIENT
SHIFTS EAST OF THE WATERS...LEAVING AN ILL DEFINED GRADIENT
BEHIND. WINDS WILL DROP UNDER 10 KT FOR TUE/TUE NIGHT WITH
DIRECTION BECOMING VARIABLE. SEABREEZE WILL INDUCE ONSHORE WINDS
NEAR SHORE ALONG WITH AN INCREASE IN WIND SPEEDS TUE AFTERNOON.
SEAS WILL RUN 3 TO 5 FT EARLY IN THE PERIOD BUT START A SLOW
DECREASE AS WIND SPEEDS START TO DROP LATE MON NIGHT. SEAS WILL BE
2 TO 4 FT TUE/TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...LIGHT NORTHEAST FLOW DEVELOPS EARLY WED AS HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST. SPEEDS START OUT AROUND 10 KT
BUT INCREASE DURING WED AS GRADIENT TIGHTENS. BY THU MORNING
NORTHEAST WINDS WILL BE 15 TO 20 KT WITH A SOLID 20 KT BY THE END OF
THU. PROLONGED AND INCREASING NORTHEAST FLOW WILL BUILD SEAS FROM 3
TO 5 FT WED/WED NIGHT TO 4 TO 7 FT THU/THU NIGHT.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...III
NEAR TERM...DCH/TRA
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/BJR








AREA FORECAST DISCUSSION

NWS BISMARCK ND

 117 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 110 PM CDT SUN APR 28 2013

SOMEWHAT DRIER AIR IS WORKING INTO THE NORTHWEST THIS
AFTERNOON...LEADING TO SOME INCREASED FIRE WEATHER CONCERNS. SEE
DISCUSSION BELOW. OVERLAND FLOODING CONTINUES NORTH...INTO THE
JAMES RIVER VALLEY...ALONG WITH CONTINUED RISES OVER MUCH OF THE
SOURIS RIVER VALLEY. UPDATED FORECASTS HAVE BEEN ISSUED...ANOTHER
UPDATE OUT SHORTLY FOR THE DES LACS RIVER NEAR FOXHOLM...NOW
EXPECTED TO CREST ABOVE MAJOR FLOOD STAGE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN FORECAST ISSUES FOR THE SHORT TERM PERIOD INCLUDE HYDRO
AND FIRE WEATHER ISSUES WHICH ARE OUTLINED BELOW.

A COLD FRONT IS CURRENTLY PUSHING SOUTHEAST OVER NORTH DAKOTA FROM
SOUTHERN CANADA EARLY THIS MORNING. AHEAD OF THE COLD
FRONT...TEMPERATURES HAVE REMAINED WELL ABOVE FREEZING THIS
MORNING...WITH TEMPERATURES MOSTLY IN THE LOWER 50S WEST TO THE
UPPER 40S EAST. THIS HAS ALLOWED FOR CONTINUED MELTING OF THE SNOW
PACK ACROSS NORTH DAKOTA. FOLLOWING THE COLD FRONTAL
PASSAGE...EXPECT COOLER AFTERNOON HIGH TEMPERATURES AS A COOLER
AIRMASS MOVES SOUTH AND OVER THE REGION. AFTERNOON HIGHS WILL
RANGE FROM THE LOW TO MID 50S ACROSS THE NORTH TO THE LOWER 70S
FAR SOUTH CENTRAL. FOR TONIGHT...TEMPERATURES WILL CONTINUE TO BE
ABOVE FREEZING ALLOWING FOR THE MELT TO CONTINUE...WITH THE EXCEPTION OF
THE TURTLE MOUNTAIN REGION WHERE TEMPERATURES MAY DROP TO NEAR 32
DEGREES.

IN REGARDS TO PRECIPITATION CHANCES...PRECIPITATION IS UNLIKELY
DURING THE SHORT TERM PERIOD. THERE HAVE BEEN SOME LIGHT RETURNS
SHOWING UP ON THE RADAR THIS MORNING...BUT WITH DEWPOINT
DEPRESSIONS ON THE ORDER OF 10 TO 20 DEGREES...NOTHING IS REACHING
THE GROUND AND THUS HAVE LEFT POPS LOW. HAVE ALSO ELIMINATED SLIGHT
CHANCE POPS ACROSS THE SOURIS RIVER BASIN BETWEEN 12Z AND
18Z...LATEST 00Z MODEL GUIDANCE AND 07Z RAP RUN KEEPS THE AREA DRY
AS OPPOSED TO THE 12Z ECMWF WHICH HAD SOME LIGHT PRECIP OVER THE
JAMES AND SOURIS RIVER VALLEY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 28 2013

THE MAIN CONCERNS IN THE EXTENDED ARE RAINFALL ACROSS THE JAMES
RIVER BASIN ON MONDAY AFTERNOON THROUGH MONDAY NIGHT. THIS IS
ASSOCIATED WITH A COMPLEX FRONTAL SYSTEM MOVING ACROSS THE REGION
MONDAY AFTERNOON AND NIGHT. BOTH GFS AND NAM KEEP SOME
INSTABILITY AHEAD OF THE COLD FRONT...AND THIS SHOULD SUPPORT
SCATTERED THUNDERSTORMS. MODELS HAVE BEEN CONSISTENTLY PAINTING
SOME LIGHT TO MODERATE QPF ALONG THE FRONT AS IT MOVES INTO THE
JAMES RIVER VALLEY...AND KEPT THIS CURRENT THINKING GOING THIS
FORECAST PERIOD. AT THIS TIME LOOKS LIKE BETTER THEN A HALF INCH
BUT LESS THAN ONE INCH FOR THE 24 HOUR PERIOD FROM MONDAY AND
MONDAY NIGHT. AT THIS TIME THE SNOW MELT RUNOFF IS NOT AS CRITICAL
ALONG THE JAMES RIVER VALLEY...AND THIS AMOUNT OF QPF WILL LIKELY
BE ABSORBED IN THE SOILS AFTER SEVERAL DAYS OF TEMPERATURES IN
THE 60S AND 70S.

INTERESTING WEATHER PATTERN DEVELOPING AS QUITE AN ANOMALOUS UPPER
LOW DEVELOPS OVER THE CENTRAL PLAINS BY THE END OF THE WEEK.
VARIOUS SCENARIOS HAVE THIS UPPER LOW RETROGRADES AND SPREAD LIGHT
PRECIPITATION INTO NORTHERN PLAINS BY THE END OF THE WEEK. THIS
COULD BE A MIX OF RAIN AND SNOW BY THEN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 110 PM CDT SUN APR 28 2013

VFR CONDITIONS THROUGH THE TAF PERIOD. EXPECT A BRISK NW WIND
GUSTING OVER 20 KTS...DIMINISHING THIS AFTERNOON...BEFORE
INCREASING AGAIN OUT OF THE SOUTHWEST OVERNIGHT INTO MONDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 257 AM CDT SUN APR 28 2013

FIRE WEATHER CONDITIONS WILL NOT BE AS SEVERE WITH COOLER TEMPS
AND HIGHER RELATIVE HUMIDITY IN THE UPPER 20S AND 30S.
HOWEVER...THERE WILL BE A FEW HOURS BETWEEN 18Z TO 21Z WHERE THERE
WILL BE MARGINAL RED FLAG CONDITIONS FOR AREAS ALONG THEN NORTH
DAKOTA/SOUTH DAKOTA STATE BORDER. HOWEVER...FOR THESE AREAS...THE
FIRE DANGER INDEX WILL BE IN THE LOW END OF THE VERY HIGH
CATEGORY. SINCE THE MARGINAL RED FLAG CONDITIONS WILL BE SHORT
LIVED...HAVE DECIDED NOT TO ISSUE ANY FIRE WEATHER HEADLINES FOR
TODAY.

ANOTHER PERIOD OF VERY HIGH FIRE DANGER IS EXPECTED MONDAY AS A
LOW PRESSURE SYSTEM PULLS WARM AND DRY AIR INTO SOUTHWEST NORTH
DAKOTA...FOLLOWED BY A COLD FRONTAL PASSAGE MONDAY AFTERNOON. THIS
WILL NEED TO BE MONITORED FOR POSSIBLE FIRE WEATHER WATCH.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN APR 28 2013

THE OVERLAND FLOOD WARNING FOR THE SOURIS BASIN AND UPPER JAMES
BASIN CONTINUES THROUGH AT LEAST THE WEEKEND. THE AGGRESSIVE SNOW MELT
CONTINUES AS TEMPERATURES HAVE REMAINED ABOVE FREEZING...AND
SIGNIFICANT RIVER RESPONSES ARE EXPECTED AT SEVERAL POINTS IN THE
SOURIS BASIN.

LOW PRESSURE SYSTEM WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS
THROUGH THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. THE BEST
CHANCE FOR RAINFALL EXCEEDING ONE HALF INCH WILL BE SOUTH OF THE
SOURIS RIVER VALLEY...BUT WITHIN THE CENTRAL AND SOUTHERN JAMES
RIVER VALLEY. AT THIS TIME SIGNIFICANT RAINFALL IS FORECAST SOUTH
OF THE REMAINING SNOW COVERED AREAS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...RK
SHORT TERM...LTH
LONG TERM...WAA
AVIATION...RK
FIRE WEATHER...LTH/WAA
HYDROLOGY...LTH







AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 540 PM EDT SUN APR 28 2013

.SYNOPSIS...
LOW PRESSURE ALONG THE INDIANA AND OHIO BORDER WILL DRIFT NORTH
AND GRADUALLY DISSIPATE BY MONDAY MORNING. HIGH PRESSURE WILL
BUILD ACROSS THE AREA LATE MONDAY THROUGH AT LEAST MIDWEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE EARLY EVENING UPDATE WAS TO REFINE TEMPERATURES THROUGH
MIDNIGHT...A LITTLE COOLER AT FIRST WHERE IT HAS BEEN
RAINING...THEN A COUPLE OF DEGREES WARMER THAN THE EARLIER
FORECAST SINCE HIGH DEWPOINTS AND WARMER AIR ARE MOVING IN FROM
THE SOUTH THIS EVENING.

EMPHASIZED SHOWERS MAINLY FOR THIS EVENING FOR NORTHWEST OHIO AND
BEFORE MIDNIGHT NORTH CENTRAL OHIO. DID NOT TRY TO TIME THE
SHOWERS AS MUCH NE OH/NW PA ALTHOUGH THE SHOWERS WILL ALMOST
CERTAINLY TAPER OFF SOMEWHAT DURING THE EARLY MORNING HOURS.

EARLIER DISCUSSION...
KIND OF A TRICKY FORECAST FOR TONIGHT. PRECIP COVERAGE CONTINUES
TO DISSIPATE. COMMA HEAD FROM THE UPPER LOW CLEARLY VISIBLE ON THE
RADAR. THE MAIN AREA OF RAIN IS NOW MOVING OUT OVER LAKE ERIE BUT
NEW DEVELOPMENT CONTINUES TO THE SOUTH. THIS SECOND WAVE OF PRECIP
WILL BE SCATTERED IN NATURE THIS EVENING. ALL OF THE NEW GUIDANCE
INCLUDING THE LATEST HRRR SHOW ABOUT 50 PERCENT COVERAGE MOST OF
THE EVENING. THE SHOWERS WILL BE CELLULAR IN NATURE WHICH WOULD
LEAD ME TO BELIEVE THERE COULD BE SOME ISOLATED THUNDER. JUST
CAN`T SEE THAT HAPPENING THOUGH GIVEN THE THICK CLOUDS AND LACK OF
INSTABILITY OVER THE AREA. WILL REMOVE THE EARLIER MENTION OF
THUNDER FROM THE FORECAST. BY 06Z ANY REMAINING PRECIP SHOULD BE
OVER THE EAST HALF OF THE AREA. CLOUDS EXTEND WEST ACROSS THE
GREAT LAKES AND SEE NO CHANCE OF CLEARING TONIGHT. SOME OF THE
GUIDANCE IS SUGGESTING SOME FOG DEVELOPMENT OVERNIGHT SO THE
EVENING CREW WILL HAVE TO WATCH THAT. USED A BLEND OF GUIDANCE
TEMPS.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS IN FAIR AGREEMENT DURING THE PERIOD AND SHOW AN UPPER
TROUGH ROTATING ACROSS THE REGION LATE TONIGHT AND MONDAY. THIS
FEATURE SHOULD KICK OFF A FEW MORE SHOWERS WITH BEST CHANCES BEING
IN THE EAST. SYNOPTIC SCALE SUBSIDENCE BEHIND THE WAVE SHOULD
BRING AN END TO THE PRECIP MONDAY EVENING. THE REMAINDER OF THE
PERIOD SHOULD THEN BE DRY AS THE LOCAL AREA REMAINS BETWEEN WEAK
SYSTEMS. WEAK RIDING WILL TRY TO OCCUR DURING THE PERIOD. THIS MAY
BE ENOUGH TO BREAK UP THE CLOUDS SOME BUT NOT ENOUGH TO CLEAR
THINGS OUT. THE AREA WILL SEE A PROLONGED PERIOD OF S TO SW FLOW
WHICH WILL MODERATE TEMPS. HIGHS COULD GET TO 70 TOMORROW IN THE
WEST AND ACROSS MOST OF THE AREA ON TUESDAY AND WEDNESDAY. LAKE
BREEZES APPEAR LIKELY IN THE AFTERNOON SO THE IMMEDIATE LAKESHORE
AREAS WILL BE COOLER. HAVE USED A BLEND OF GUIDANCE MOST OF THE
PERIOD.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE APPEARS IT WILL BECOME THE DOMINATING WEATHER FEATURE
ACROSS THE AREA FOR A GOOD PART OF THE EXTENDED PERIODS. UPPER LEVEL
RIDGE BUILDS OVER THE EASTERN UNITED STATES AND SETS UP A SURFACE
HIGH OVER THE EASTERN SEABOARD.  THIS FEATURE WILL KEEP A SOUTHERLY
COMPONENT TO THE WIND ALLOWING FOR WARM AIR ADVECTION TO TAKE PLACE
INTO FRIDAY. FRONTAL BOUNDARY WILL STALL WEST OF THE REGION WILL
MAKE SLOW PROGRESS INTO THE AREA ON SATURDAY.  THIS FEATURE WILL
BRING THE NEXT CHANCE OF RAIN SATURDAY INTO SATURDAY NIGHT. THERE IS
THE POSSIBILITY THAT THE FRONT COULD LINGER INTO THE AREA ON SUNDAY
WITH A CHANCE OF SHOWERS.  MADE A FEW ADJUSTMENTS TO TEMPERATURES
BUT NOTHING MAJOR AS MODELS ARE FAIRLY CONSISTENT WITH YESTERDAYS
RUN.

&&

.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
RAIN CONTINUES TO ROTATE THROUGH THE AREA THIS AFTERNOON WITH THE
MAIN BAND LIFTING NORTHEAST ACROSS NORTHEAST OHIO AND NORTHWEST
PENNSYLVANIA. SECONDARY AREA OF CONVECTIVE SHOWERS CONTINUES TO
DEVELOP OVER SOUTH CENTRAL OHIO AND THIS ACTIVITY WILL LIFT
NORTHEAST. ANTICIPATE THE ONLY PLACE WE MAY HEAR THUNDER IS AT
AKRON CANTON AND YOUNGSTOWN. WILL LEAVE MENTION OF THUNDER OUT OF
THE FORECAST ELSEWHERE. PRECIPITATION IS JUST ABOUT DONE IN
NORTHWEST OHIO FOR THE WIDESPREAD RAIN. MAY SEE SOME SCATTERED
SHOWER ACTIVITY THROUGH THE REST OF THE AFTERNOON.

CEILINGS WILL REMAIN FAIRLY LOW THROUGH MUCH OF THE PERIOD BUT
WILL SEE SOME IMPROVEMENT TOWARD THE END OF THE FORECAST PERIOD.
VISIBILITIES COULD BE REDUCED OVERNIGHT BY FOG DEVELOPMENT DUE TO
MOIST GROUND. NOT EXPECTING ANY WORSE THAN A HALF MILE AT ANY
LOCATION.

.OUTLOOK...NON-VFR POSSIBLE IN FOG THURSDAY MORNING.

&&

.MARINE...
ONCE THIS STORM SYSTEM MOVES NORTHEAST OF THE AREA TONIGHT AND
MONDAY MORNING...LOOKING AT RATHER QUIET WEATHER ON THE LAKE. NOT
ANTICIPATING ANY STRONG STORM SYSTEMS TO SUPPORT STRONGER WINDS.
THEREFORE...WILL KEEP WINDS LIGHT AND WAVES ON THE LIGHT SIDE
THROUGH THE PERIOD.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KOSARIK/KUBINA
NEAR TERM...KOSARIK/KUBINA
SHORT TERM...KUBINA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY







AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 312 PM EDT SUN APR 28 2013

.SYNOPSIS...
LOW PRESSURE OVER CENTRAL INDIANA WILL MOVE INTO NORTHWEST OHIO
AND DISSIPATE OVERNIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA
LATE MONDAY THROUGH MIDWEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
KIND OF A TRICKY FORECAST FOR TONIGHT. PRECIP COVERAGE CONTINUES
TO DISSIPATE. COMMA HEAD FROM THE UPPER LOW CLEARLY VISIBLE ON THE
RADAR. THE MAIN AREA OF RAIN IS NOW MOVING OUT OVER LAKE ERIE BUT
NEW DEVELOPMENT CONTINUES TO THE SOUTH. THIS SECOND WAVE OF PRECIP
WILL BE SCATTERED IN NATURE THIS EVENING. ALL OF THE NEW GUIDANCE
INCLUDING THE LATEST HRRR SHOW ABOUT 50 PERCENT COVERAGE MOST OF
THE EVENING. THE SHOWERS WILL BE CELLULAR IN NATURE WHICH WOULD
LEAD ME TO BELIEVE THERE COULD BE SOME ISOLATED THUNDER. JUST
CAN`T SEE THAT HAPPENING THOUGH GIVEN THE THICK CLOUDS AND LACK OF
INSTABILITY OVER THE AREA. WILL REMOVE THE EARLIER MENTION OF
THUNDER FROM THE FORECAST. BY 06Z ANY REMAINING PRECIP SHOULD BE
OVER THE EAST HALF OF THE AREA. CLOUDS EXTEND WEST ACROSS THE
GREAT LAKES AND SEE NO CHANCE OF CLEARING TONIGHT. SOME OF THE
GUIDANCE IS SUGGESTING SOME FOG DEVELOPMENT OVERNIGHT SO THE
EVENING CREW WILL HAVE TO WATCH THAT. USED A BLEND OF GUIDANCE
TEMPS.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS IN FAIR AGREEMENT DURING THE PERIOD AND SHOW AN UPPER
TROUGH ROTATING ACROSS THE REGION LATE TONIGHT AND MONDAY. THIS
FEATURE SHOULD KICK OFF A FEW MORE SHOWERS WITH BEST CHANCES BEING
IN THE EAST. SYNOPTIC SCALE SUBSIDENCE BEHIND THE WAVE SHOULD
BRING AN END TO THE PRECIP MONDAY EVENING. THE REMAINDER OF THE
PERIOD SHOULD THEN BE DRY AS THE LOCAL AREA REMAINS BETWEEN WEAK
SYSTEMS. WEAK RIDING WILL TRY TO OCCUR DURING THE PERIOD. THIS MAY
BE ENOUGH TO BREAK UP THE CLOUDS SOME BUT NOT ENOUGH TO CLEAR
THINGS OUT. THE AREA WILL SEE A PROLONGED PERIOD OF S TO SW FLOW
WHICH WILL MODERATE TEMPS. HIGHS COULD GET TO 70 TOMORROW IN THE
WEST AND ACROSS MOST OF THE AREA ON TUESDAY AND WEDNESDAY. LAKE
BREEZES APPEAR LIKELY IN THE AFTERNOON SO THE IMMEDIATE LAKESHORE
AREAS WILL BE COOLER. HAVE USED A BLEND OF GUIDANCE MOST OF THE
PERIOD.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
HIGH PRESSURE APPEARS IT WILL BECOME THE DOMINATING WEATHER FEATURE
ACROSS THE AREA FOR A GOOD PART OF THE EXTENDED PERIODS. UPPER LEVEL
RIDGE BUILDS OVER THE EASTERN UNITED STATES AND SETS UP A SURFACE
HIGH OVER THE EASTERN SEABOARD.  THIS FEATURE WILL KEEP A SOUTHERLY
COMPONENT TO THE WIND ALLOWING FOR WARM AIR ADVECTION TO TAKE PLACE
INTO FRIDAY. FRONTAL BOUNDARY WILL STALL WEST OF THE REGION WILL
MAKE SLOW PROGRESS INTO THE AREA ON SATURDAY.  THIS FEATURE WILL
BRING THE NEXT CHANCE OF RAIN SATURDAY INTO SATURDAY NIGHT. THERE IS
THE POSSIBILITY THAT THE FRONT COULD LINGER INTO THE AREA ON SUNDAY
WITH A CHANCE OF SHOWERS.  MADE A FEW ADJUSTMENTS TO TEMPERATURES
BUT NOTHING MAJOR AS MODELS ARE FAIRLY CONSISTENT WITH YESTERDAYS
RUN.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
RAIN CONTINUES TO ROTATE THROUGH THE AREA THIS AFTERNOON WITH THE
MAIN BAND LIFTING NORTHEAST ACROSS NORTHEAST OHIO AND NORTHWEST
PENNSYLVANIA. SECONDARY AREA OF CONVECTIVE SHOWERS CONTINUES TO
DEVELOP OVER SOUTH CENTRAL OHIO AND THIS ACTIVITY WILL LIFT
NORTHEAST. ANTICIPATE THE ONLY PLACE WE MAY HEAR THUNDER IS AT
AKRON CANTON AND YOUNGSTOWN. WILL LEAVE MENTION OF THUNDER OUT OF
THE FORECAST ELSEWHERE. PRECIPITATION IS JUST ABOUT DONE IN
NORTHWEST OHIO FOR THE WIDESPREAD RAIN. MAY SEE SOME SCATTERED
SHOWER ACTIVITY THROUGH THE REST OF THE AFTERNOON.

CEILINGS WILL REMAIN FAIRLY LOW THROUGH MUCH OF THE PERIOD BUT
WILL SEE SOME IMPROVEMENT TOWARD THE END OF THE FORECAST PERIOD.
VISIBILITIES COULD BE REDUCED OVERNIGHT BY FOG DEVELOPMENT DUE TO
MOIST GROUND. NOT EXPECTING ANY WORSE THAN A HALF MILE AT ANY
LOCATION.

.OUTLOOK...NON-VFR POSSIBLE IN FOG THURSDAY MORNING.

&&

.MARINE...
ONCE THIS STORM SYSTEM MOVES NORTHEAST OF THE AREA TONIGHT AND
MONDAY MORNING...LOOKING AT RATHER QUIET WEATHER ON THE LAKE. NOT
ANTICIPATING ANY STRONG STORM SYSTEMS TO SUPPORT STRONGER WINDS.
THEREFORE...WILL KEEP WINDS LIGHT AND WAVES ON THE LIGHT SIDE
THROUGH THE PERIOD.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 258 PM EDT SUN APR 28 2013

.SYNOPSIS...
A NEARBY FRONT WILL DISSIPATE EARLY THIS WEEK AS DRIER AIR MOVES IN
FROM THE WEST. A RIDGE OF HIGH PRESSURE WILL THEN STRENGTHEN ACROSS
THE AREA BY MID-WEEK. A CLOSED OFF UPPER LOW OVER THE MID
MISSISSIPPI VALLEY LATE IN THE WEEK IS EXPECTED TO BRING MORE
UNSETTLED WEATHER TO OUR REGION.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 255 PM...KFFC STORM TRACK INFO CONTINUES TO SHOW NUMEROUS
CELLS ACROSS AL/NRN GA...TRACKING TOWARD THE WESTERN CAROLINAS. SPC
MESOANALYSIS TRENDS AND RAP INDICATE A FIELD OF WEAK CAPE VALUES
WILL SPREAD NORTH ALONG THE BORDER OF CAD THIS AFTERNOON...MAINLY
EAST OF I-85 AND ACROSS THE TN BORDER OF THE NC MTNS. THE NOSE OF
THE CAD MAY EXTEND ACROSS NE GA. HOWEVER...LATEST SATELLITE BLENDED
TOTAL PRECIP WATER CONTINUED TO INDICATE A PLUME OF 1.1 TO 1.2 INCHES
ACROSS THE WESTERN CWA...OR AROUND 170 PERCENT OF NORMAL. SATELLITE
WATER VAPOR INDICATES A CONNECTION AS FAR SOUTH AS NRN MEXICO. THIS
RICH MOISTURE ENVIRONMENT WILL LIKELY REMAIN AHEAD OF AN APPROACHING
H5 TROF. IN ADDITION...THE FORECAST AREA SHOULD REMAIN UNDER A
RIBBON OF JET DIVERGENCE...ASSOCIATED WITH A JET EAST OF THE CLOSED
LOW OVER THE OHIO RIVER VALLEY. THE BROAD UPPER LEVEL FORCING
COMBINED WITH DEEP MOISTURE AND LIMITED INSTABILITY SHOULD PROVIDE A
SUPPORTIVE ENVIRONMENT OF MODERATE SHOWERS AND EMBEDDED TSRA ACROSS
THE WESTERN CAROLINAS AND NE GA THROUGH MID EVENING.

CONVECTION ALLOWING MODELS...CAMS...INDICATE THAT THE BEST WINDOW
FOR TSRA WILL OCCUR LATER THIS AFTERNOON INTO EARLY THIS
EVENING...RESULTING FROM THE GREATEST OVERLAP OF UPPER SUPPORT AND
INSTABILITY. THIS WILL BE PRIME TIME FOR THE HIGHEST RAINFALL
RATES...INCREASING THE POTENTIAL FOR FLASH FLOODING. ONE HOUR FFG
RANGES FROM 1.5 TO 2.5 INCHES ACROSS THE FORECAST AREA. SOCIAL MEDIA
REPORTS...AUTOMATED RAIN GAUGES...AND RADAR RAINFALL ESTIMATES
INDICATE THE GREATEST RAINFALL AMOUNTS SO FAR TODAY REMAIN OVER THE
SOUTHERN AND CENTRAL NC MTNS WITH ANOTHER SWATH ACROSS EXTREME NE
GA...AMOUNTS FROM 1.5 TO 2.5 INCHES. IT IS INTERESTING THAT THE CAMS
SPREAD DEEP CONVECTION ACROSS THE I-85 CORRIDOR...INCLUDING THE CLT
METRO AREA EARLY THIS EVENING. HOWEVER...THE LINEAR APPEARANCE TO
THE CONVECTION SUGGEST THAT THE MOTION WILL BE HIGH ENOUGH TO NOT
SUPPORT AN EXPANSION IN THE FFA.

THE COVERAGE OF RAINFALL SHOULD BEGIN TO DECREASE FROM WEST TO EAST
EARLY MON MORNING WITH THE ARRIVAL OF THE MID LEVEL TROF. AT THE
SFC...A COMPLEX COMBINATION OF THE WEDGE BOUNDARY AND WEAK COLD
FRONT WILL MAKE THE TEMPERATURE CHALLENGING. HOWEVER...THE COOL
CURRENT TEMPERATURES WILL LIKE POSITION TEMPERATURES TO RISE
OVERNIGHT AS CAD ERODES. IN ADDITION...CONDITIONS WILL FEATURE LOW
CLOUDS AND FOG OVERNIGHT. ON MONDAY...CLOUD COVER WILL CONTINUE TO
DECREASE...ALLOWING SOME BREAKS. MESOSCALE MODELS INDICATE A BAND OF
WEAK CAPE WILL DEVELOP ACROSS THE FOOTHILLS DURING THE AFTERNOON.
THE BAND OF CAPE ALONG AND EAST OF WEAK COLD FRONT MAY SUPPORT
ANOTHER BAND OF SHRA...POSSIBLY TSRA DURING THE AFTERNOON. HIGHS ARE
FORECAST TO PEAK 3 TO 5 DEGREES BELOW NORMAL.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM EDT SUNDAY...AN H5 RIDGE WILL BUILD OVER THE ERN CONUS
ON TUE...BUT WITH LOW PRESSURE PERSISTING UNDER THE RIDGE NEAR THE
WRN GULF COAST. LOW LEVELS WILL REMAIN FAIRLY MOIST ACROSS THE
REGION...AND MORNING LOW CLOUDS/FOG LOOK LIKE A GOOD BET LATE MON
NIGHT/TUE MORNING. AFTER SOME BRIEF SCATTERING...A RETURN TO LIGHT
SE UPSLOPE FLOW WILL BRING CLOUDS BACK TO THE AREA BY LATER IN THE
DAY. PROFILES EXIHIBIT SOME CAPPING ON TUE...BUT THIS MIGHT BE
OVERCOME BY LATE AFTN. WILL FEATURE ISOLD AFTN CONVECTIVE
COVERAGE...ESPECIALLY NEAR THE ERN ESCARPMENT...WITH TEMPERATURES
WARMING TO NEAR CLIMATE NORMALS THROUGHOUT.

ANOTHER ROUND OF LOW CLOUDS/FOG ARE EXPECTED LATE TUE NIGHT/WED
MORNING. THERE IS CONSIDERABLE UNCERTAINTY OVER HOW FAR EAST THE
GULF COAST LOW PRES SYSTEM GETS BY WED...BUT THE EASTERLY ATLANTIC
FETCH AROUND HIGH PRES OVER THE NE U.S. WILL DEEPEN LOW LEVEL
MOISTURE THROUGH WED IN ANY CASE. LESS CAPPING AND MORE MOISTURE IS
EXHIBITED IN PROFILES ON WED...ALONG WITH BETTER TRIGGERING EASTERLY
UPSLOPE FLOW. WILL FEATURE SLIGHTLY MORE ROBUST CHC AFTN POPS WITH
TEMPS TRIMMED A DEGREE OR TWO BELOW TUE MAXES.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 225 PM SUNDAY...THE MEDIUM RANGE MODELS ARE IN BETTER
AGREEMENT FOR LATE IN THE WEEK AND THROUGH THE START OF NEXT WEEK.
THIS PERIOD BEGINS AT 00Z THURSDAY WITH A SHARP 500MB RIDGE OVER THE
EAST COAST AS A TROUGH DIGS SOUTH OVER THE PLAINS STATES. THE ECMWF
HAS BEEN THE DRIER OF THE MODELS LATE IN THE WEEK FOR THE EAST COAST
WITH THE RIDGE HOLDING FROM THE CAROLINAS NORTH. THIS RIDGE SHOULD
HOLD FOR OUR AREA FROM WEDNESDAY NIGHT THROUGH EARLY FRIDAY AND
KEEPING POPS AT SLIGHT OR LOW CHANCE AT BEST. THIS SHARP DIP IN THE
UPPER FLOW IS FORECAST TO GET PINCHED OFF THURSDAY NIGHT AND BECOME
A CLOSED LOW SOMEWHERE OVER THE MID SECTION OF THE NATION.  SURFACE
LOWS ARE EXPECTED TO FORM ALONG A BOUNDARY EXTENDING NORTH FROM THE
GULF THURSDAY NIGHT INTO FRIDAY BUT THIS WILL PRIMARILY AFFECT
LOCATIONS WEST OF THE CAROLINA AND GEORGIA MOUNTAINS. THIS BOUNDARY
WILL MOVE EAST AND THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THIS
WILL SLOWLY CROSS OUR AREA FRIDAY NIGHT THROUGH SATURDAY. LOW LEVEL
FLOW WILL GO FROM A ENE DIRECTION TO A SE UPSLOPE FLOW FRIDAY NIGHT
AND EARLY SATURDAY ALONG THE BLUE RIDGE ESCARPMENT ENHANCING
RAINFALL FOR THE SRN MTNS AND FOOTHILLS. GFS HAS 30 TO 35 KT 925MB
FLOW FROM THE SE EARLY SATURDAY WITH A WEST TO NORTH 10 TO 20 KT
FLOW OVER GA AND TN ATTM. GFS HAS CAPE VALUES REACHING 300 TO 500
OVER THE UPPER SAVANNAH VALLEY EARLY SATURDAY AFTERNOON. AS THE
UPPER LOW LINGERS OVER IOWA LATE IN THE WEEKEND...THE FRONTAL
BOUNDARY EXTENDING FROM THE CAROLINAS TO THE GREAT LAKES WILL LINGER
NEAR THE SAME AREA INTO SUNDAY NIGHT. DAY TIME HIGHS WILL BE BELOW
NORMAL THROUGH THE PERIOD AND LOWS NEAR NORMAL.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...WESTERN CAROLINA TERMINALS APPEAR WITHIN THE
REGION OF CAD...THEREFORE...THE AREA OF IFR TO LIFR CEILINGS. CLT
REMAINS ON THE VERY EDGE OF THE CAD BOUNDARY. HOWEVER...THE CURRENT
AREA OF MODERATE RAIN ACROSS THE CLT TERMINAL SHOULD REINFORCE THE
CAD...FORCING THE BOUNDARY FURTHER EAST. NO GUIDANCE HANDLES THE
POSITION WELL...BUT WRF INDICATED THAT A SIMILAR BOUNDARY SHIFT
WOULD OCCUR LATER TODAY. I WILL KEEP CLT IN THE WEDGE CLOUDS THROUGH
SUNSET. AFTER SUNSET...ALL GUIDANCE INDICATES WIDESPREAD IFR TO LIFR
CLOUDS WILL CONTINUE OVERNIGHT. CONVECTION ALLOWING MODELS TIME A
LINE OF SHRA/TSRA ACROSS THE WESTERN CAROLINAS EARLY THIS
EVENING...I WILL INDICATE A VCTS...TEMPO...OR PROB30 FOR THE PERIOD
OF GREATEST TSRA RISK. AFTER SUNRISE MONDAY...DOWNSLOPING WINDS
SHOULD RESULT IN A WEST TO EAST RETURN TO VFR CLOUDS WITH P6SM.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            19-01Z        01-07Z        07-13Z        13-19Z
KCLT       HIGH  83%     MED   79%     MED   65%     HIGH  92%
KGSP       MED   78%     MED   72%     MED   70%     HIGH  95%
KAVL       HIGH 100%     HIGH  94%     HIGH  86%     HIGH  86%
KHKY       MED   78%     HIGH  81%     HIGH  83%     HIGH  97%
KGMU       HIGH  84%     HIGH  84%     MED   62%     HIGH  93%
KAND       HIGH  86%     MED   61%     MED   66%     HIGH  95%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR GAZ010-017-
     018.
NC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ048-
     051>053-058-059-062>065-507-509-510.
SC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR SCZ001>007.

&&

$$
SYNOPSIS...DEO
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...DEO
AVIATION...NED







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 211 PM EDT SUN APR 28 2013

.SYNOPSIS...
A NEARBY FRONT WILL DISSIPATE EARLY THIS WEEK AS DRIER AIR MOVES IN
FROM THE WEST. A RIDGE OF HIGH PRESSURE WILL THEN STRENGTHEN ACROSS
THE AREA BY MID-WEEK. A CLOSED OFF UPPER LOW OVER THE MID
MISSISSIPPI VALLEY LATE IN THE WEEK IS EXPECTED TO BRING MORE
UNSETTLED WEATHER TO OUR REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...LATEST SATELLITE BLENDED TOTAL PRECIP WATER
INDICATED A PLUME OF 1.1 TO 1.2 INCHES ACROSS THE WESTERN CWA...OR
AROUND 170 PERCENT OF NORMAL. SATELLITE WATER VAPOR INDICATES A
CONNECTION AS FAR SOUTH AS NRN MEXICO. THIS RICH MOISTURE
ENVIRONMENT WILL LIKELY REMAIN AHEAD OF AN APPROACHING H5 TROF. IN
ADDITION...THE FORECAST AREA SHOULD REMAIN UNDER A RIBBON OF JET
DIVERGENCE...ASSOCIATED WITH A JET EAST OF THE CLOSED LOW OVER THE
OHIO RIVER VALLEY. THE BROAD UPPER LEVEL SUPPORT COMBINED WITH LLVL
UPSLOPE FLOW AND ISENTROPIC LIFT HAS SUPPORTED A WIDE BAND OF RAIN
AND EMBEDDED TSRA ACROSS THE MTNS AND FOOTHILLS THIS MORNING.
HOWEVER...SPC MESOANALYSIS TRENDS AND RAP INDICATE A FIELD OF WEAK
CAPE VALUES WILL SPREAD NORTH ALONG THE BORDER OF CAD THIS
AFTERNOON...MAINLY EAST OF I-85 AND ACROSS THE TN BORDER OF THE NC
MTNS. THE INCREASE IN CONDITIONAL INSTABILITY SHOULD RESULT IN
GREATER TSRA COVERAGE. CONVECTION ALLOWING MODELS...CAMS...INDICATE
THAT THE BEST WINDOW FOR TSRA WILL OCCUR LATE THIS AFTERNOON INTO
EARLY THIS EVENING...RESULTING FROM THE GREATEST OVERLAP OF UPPER
SUPPORT AND INSTABILITY. THIS WILL BE PRIME TIME FOR THE HIGHEST
RAINFALL RATES...INCREASING THE POTENTIAL FOR FLASH FLOODING. IT IS
INTERESTING THAT THE CAMS SPREAD DEEP CONVECTION ACROSS THE CLT
METRO AREA EARLY THIS EVENING. HOWEVER...THE LINEAR APPEARANCE TO
THE CONVECTION SUGGEST THAT THE MOTION WILL BE HIGH ENOUGH TO NOT
SUPPORT AN EXPANSION IN THE FFA.

I WILL UPDATE THE FORECAST TO LIMIT ANY ADDITIONAL HEATING ACROSS
THE MTNS AND FOOTHILLS THIS AFTERNOON. I HAVE ALSO INCREASE QPF
ACROSS THE MTNS AND FOOTHILLS INTO THE EARLY EVENING.

AS OF 945 AM...I HAVE MADE SIGNIFICANT CHANGES TO THE FORECAST TO
ACCOUNT FOR EXPECTED HEAVY QPF AND TSRA ACROSS THE WESTERN CAROLINAS
AND NE GA TODAY. REGIONAL RADAR INDICATES A WIDE BAND OF SHRA AND
TSRA ACROSS THE SOUTHERN AND CENTRAL NC MTNS...SW TO AL. FFC STI
INDICATES UNIFORM MOTION OF CELL NE ACROSS GA AND SOUTHERN
TN...REACH THE CAROLINA MTNS AND NE GA THROUGH EARLY EVENING. THE
ATMOSPHERE FEATURE PW VALUES NEAR 200 PERCENT OF NORMAL...SOURCED
FROM THE GULF. AS A MID LEVEL TROF APPROACHES THIS AFTERNOON...LIFT
AND INSTABILITY WILL INCREASE...SUPPORTING ANOTHER BAND OF TSRA TO
CROSS THE REGION. FFG ACROSS THE MTNS IS GENERALLY LOW...1.5 TO 2
INCHES PER HOUR. I WILL ISSUE A FLASH FLOOD WATCH FOR EXTREME NE
GA...THE CENTRAL AND SOUTHERN NC MTNS...AND AREAS NORTH OF I-85
ACROSS THE UPSTATE OF SC UNTIL 8 PM.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...BASED UPON THE LATEST MODEL GUIDANCE...
CONFIDENCE IS INCREASING THAT THE WEAKENING UPPER TROUGH AXIS WILL
SHIFT INTO THE MID-ATLANTIC ON MONDAY...TAKING THE DEEPER MOISTURE
AND FORCING ALONG WITH IT. LIKELY POPS WILL LINGER ACROSS THE
EASTERN ZONES AT THE START OF THE PERIOD...BUT SYNOPTICALLY FORCED
PRECIP SHOULD BE EAST OF THE AREA BY AFTERNOON. HOWEVER...THE LOWER
LEVELS WILL REMAIN MOIST. IN FACT...WITH THE DRYING MID/UPPER
LEVELS...WARMER TEMPS AND IMPROVED INSTABILITY ARE EXPECTED MONDAY
AFTERNOON. THIS IS SHOULD RESULT IN DEVELOPMENT OF SCATTERED
CONVECTION...PARTICULARLY OVER THE MTNS...AND CHANCE POPS WILL BE
CARRIED THROUGH THE AFTERNOON AND EVENING.

BY TUESDAY...STRONG HEIGHT FALLS OVER THE WESTERN CONUS WILL ACT TO
BUILD THE DOWNSTREAM RIDGE. THIS WILL STRENGTHEN THE SURFACE HIGH
OVER THE CANADIAN MARITIMES AND SHARPEN THE RIDGE FROM THE MID-
ATLANTIC INTO THE CAROLINAS. A DRIER LOW LEVEL AIR MASS WILL ADVECT
AT LEAST AS FAR SOUTH/WEST AS THE MID-ATLANTIC. HOWEVER...IT IS
INCONCLUSIVE AS TO WHETHER THIS DRIER AIR WILL PENETRATE AS FAR
SOUTH AS THE WESTERN CAROLINAS. IN FACT...THE GFS KEEPS CONDITIONS
QUITE MOIST DURING THIS TIME. THEREFORE...WE WILL MAINTAIN SMALL/
MAINLY DIURNAL POPS THROUGH THE END OF THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...THE GLOBAL MODELS ARE CONVERGING TOWARD
AGREEMENT IN ESTABLISHMENT OF AN OMEGA BLOCKING PATTERN DURING THE
MEDIUM RANGE...WITH LOW PRESSURE LIKELY SETTLING SOMEWHERE IN THE
CENTRAL CONUS. IF ANYTHING...THE MODELS ARE SIGNALING THAT THE
SURFACE HIGH WILL GRADUALLY BUILD FARTHER SOUTH ALONG THE EAST
COAST...ALLOWING A DRYING LOW LEVEL AIR MASS TO FILTER INTO THE
SOUTHEAST. BASED UPON THIS...OUR CURRENT POP FORECAST APPEARS TOO
PESSIMISTIC DURING THE LATTER HALF OF THE WEEK. WE HAVE BEGUN THE
PROCESS OF BACKING AWAY FROM HIGHER POPS...BUT WILL WAIT UNTIL A
CLEAR TREND BECOMES ESTABLISHED IN GUIDANCE BEFORE MAKING MORE
DRAMATIC CHANGES.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...WESTERN CAROLINA TERMINALS APPEAR WITHIN THE
REGION OF CAD...THEREFORE...THE AREA OF IFR TO LIFR CEILINGS. CLT
REMAINS ON THE VERY EDGE OF THE CAD BOUNDARY. HOWEVER...THE CURRENT
AREA OF MODERATE RAIN ACROSS THE CLT TERMINAL SHOULD REINFORCE THE
CAD...FORCING THE BOUNDARY FURTHER EAST. NO GUIDANCE HANDLES THE
POSITION WELL...BUT WRF INDICATED THAT A SIMILAR BOUNDARY SHIFT
WOULD OCCUR LATER TODAY. I WILL KEEP CLT IN THE WEDGE CLOUDS THROUGH
SUNSET. AFTER SUNSET...ALL GUIDANCE INDICATES WIDESPREAD IFR TO LIFR
CLOUDS WILL CONTINUE OVERNIGHT. CONVECTION ALLOWING MODELS TIME A
LINE OF SHRA/TSRA ACROSS THE WESTERN CAROLINAS EARLY THIS
EVENING...I WILL INDICATE A VCTS...TEMPO...OR PROB30 FOR THE PERIOD
OF GREATEST TSRA RISK. AFTER SUNRISE MONDAY...DOWNSLOPING WINDS
SHOULD RESULT IN A WEST TO EAST RETURN TO VFR CLOUDS WITH P6SM.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       MED   77%     HIGH  80%     MED   73%     HIGH  94%
KGSP       MED   78%     MED   78%     MED   70%     HIGH  95%
KAVL       HIGH 100%     HIGH  96%     HIGH  83%     HIGH  90%
KHKY       MED   77%     HIGH  82%     HIGH  81%     HIGH  95%
KGMU       HIGH  84%     HIGH  88%     MED   66%     HIGH  95%
KAND       HIGH  96%     MED   77%     MED   79%     HIGH  93%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR GAZ010-017-
     018.
NC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ048-
     051>053-058-059-062>065-507-509-510.
SC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR SCZ001>007.

&&

$$
SYNOPSIS...JDL
NEAR TERM...NED
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...NED







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 1237 PM EDT SUN APR 28 2013

.SYNOPSIS...
A NEARBY FRONT WILL DISSIPATE EARLY THIS WEEK AS DRIER AIR MOVES IN
FROM THE WEST. A RIDGE OF HIGH PRESSURE WILL THEN STRENGTHEN ACROSS
THE AREA BY MID-WEEK. A CLOSED OFF UPPER LOW OVER THE MID
MISSISSIPPI VALLEY LATE IN THE WEEK IS EXPECTED TO BRING MORE
UNSETTLED WEATHER TO OUR REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...LATEST SATELLITE BLENDED TOTAL PRECIP WATER
INDICATED A PLUME OF 1.1 TO 1.2 INCHES ACROSS THE WESTERN CWA...OR
AROUND 170 PERCENT OF NORMAL. SATELLITE WATER VAPOR INDICATES A
CONNECTION AS FAR SOUTH AS NRN MEXICO. THIS RICH MOISTURE
ENVIRONMENT WILL LIKELY REMAIN AHEAD OF AN APPROACHING H5 TROF. IN
ADDITION...THE FORECAST AREA SHOULD REMAIN UNDER A RIBBON OF JET
DIVERGENCE...ASSOCIATED WITH A JET EAST OF THE CLOSED LOW OVER THE
OHIO RIVER VALLEY. THE BROAD UPPER LEVEL SUPPORT COMBINED WITH LLVL
UPSLOPE FLOW AND ISENTROPIC LIFT HAS SUPPORTED A WIDE BAND OF RAIN
AND EMBEDDED TSRA ACROSS THE MTNS AND FOOTHILLS THIS MORNING.
HOWEVER...SPC MESOANALYSIS TRENDS AND RAP INDICATE A FIELD OF WEAK
CAPE VALUES WILL SPREAD NORTH ALONG THE BORDER OF CAD THIS
AFTERNOON...MAINLY EAST OF I-85 AND ACROSS THE TN BORDER OF THE NC
MTNS. THE INCREASE IN CONDITIONAL INSTABILITY SHOULD RESULT IN
GREATER TSRA COVERAGE. CONVECTION ALLOWING MODELS...CAMS...INDICATE
THAT THE BEST WINDOW FOR TSRA WILL OCCUR LATE THIS AFTERNOON INTO
EARLY THIS EVENING...RESULTING FROM THE GREATEST OVERLAP OF UPPER
SUPPORT AND INSTABILITY. THIS WILL BE PRIME TIME FOR THE HIGHEST
RAINFALL RATES...INCREASING THE POTENTIAL FOR FLASH FLOODING. IT IS
INTERESTING THAT THE CAMS SPREAD DEEP CONVECTION ACROSS THE CLT
METRO AREA EARLY THIS EVENING. HOWEVER...THE LINEAR APPEARANCE TO
THE CONVECTION SUGGEST THAT THE MOTION WILL BE HIGH ENOUGH TO NOT
SUPPORT AN EXPANSION IN THE FFA.

I WILL UPDATE THE FORECAST TO LIMIT ANY ADDITIONAL HEATING ACROSS
THE MTNS AND FOOTHILLS THIS AFTERNOON. I HAVE ALSO INCREASE QPF
ACROSS THE MTNS AND FOOTHILLS INTO THE EARLY EVENING.

AS OF 945 AM...I HAVE MADE SIGNIFICANT CHANGES TO THE FORECAST TO
ACCOUNT FOR EXPECTED HEAVY QPF AND TSRA ACROSS THE WESTERN CAROLINAS
AND NE GA TODAY. REGIONAL RADAR INDICATES A WIDE BAND OF SHRA AND
TSRA ACROSS THE SOUTHERN AND CENTRAL NC MTNS...SW TO AL. FFC STI
INDICATES UNIFORM MOTION OF CELL NE ACROSS GA AND SOUTHERN
TN...REACH THE CAROLINA MTNS AND NE GA THROUGH EARLY EVENING. THE
ATMOSPHERE FEATURE PW VALUES NEAR 200 PERCENT OF NORMAL...SOURCED
FROM THE GULF. AS A MID LEVEL TROF APPROACHES THIS AFTERNOON...LIFT
AND INSTABILITY WILL INCREASE...SUPPORTING ANOTHER BAND OF TSRA TO
CROSS THE REGION. FFG ACROSS THE MTNS IS GENERALLY LOW...1.5 TO 2
INCHES PER HOUR. I WILL ISSUE A FLASH FLOOD WATCH FOR EXTREME NE
GA...THE CENTRAL AND SOUTHERN NC MTNS...AND AREAS NORTH OF I-85
ACROSS THE UPSTATE OF SC UNTIL 8 PM.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...BASED UPON THE LATEST MODEL GUIDANCE...
CONFIDENCE IS INCREASING THAT THE WEAKENING UPPER TROUGH AXIS WILL
SHIFT INTO THE MID-ATLANTIC ON MONDAY...TAKING THE DEEPER MOISTURE
AND FORCING ALONG WITH IT. LIKELY POPS WILL LINGER ACROSS THE
EASTERN ZONES AT THE START OF THE PERIOD...BUT SYNOPTICALLY FORCED
PRECIP SHOULD BE EAST OF THE AREA BY AFTERNOON. HOWEVER...THE LOWER
LEVELS WILL REMAIN MOIST. IN FACT...WITH THE DRYING MID/UPPER
LEVELS...WARMER TEMPS AND IMPROVED INSTABILITY ARE EXPECTED MONDAY
AFTERNOON. THIS IS SHOULD RESULT IN DEVELOPMENT OF SCATTERED
CONVECTION...PARTICULARLY OVER THE MTNS...AND CHANCE POPS WILL BE
CARRIED THROUGH THE AFTERNOON AND EVENING.

BY TUESDAY...STRONG HEIGHT FALLS OVER THE WESTERN CONUS WILL ACT TO
BUILD THE DOWNSTREAM RIDGE. THIS WILL STRENGTHEN THE SURFACE HIGH
OVER THE CANADIAN MARITIMES AND SHARPEN THE RIDGE FROM THE MID-
ATLANTIC INTO THE CAROLINAS. A DRIER LOW LEVEL AIR MASS WILL ADVECT
AT LEAST AS FAR SOUTH/WEST AS THE MID-ATLANTIC. HOWEVER...IT IS
INCONCLUSIVE AS TO WHETHER THIS DRIER AIR WILL PENETRATE AS FAR
SOUTH AS THE WESTERN CAROLINAS. IN FACT...THE GFS KEEPS CONDITIONS
QUITE MOIST DURING THIS TIME. THEREFORE...WE WILL MAINTAIN SMALL/
MAINLY DIURNAL POPS THROUGH THE END OF THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...THE GLOBAL MODELS ARE CONVERGING TOWARD
AGREEMENT IN ESTABLISHMENT OF AN OMEGA BLOCKING PATTERN DURING THE
MEDIUM RANGE...WITH LOW PRESSURE LIKELY SETTLING SOMEWHERE IN THE
CENTRAL CONUS. IF ANYTHING...THE MODELS ARE SIGNALING THAT THE
SURFACE HIGH WILL GRADUALLY BUILD FARTHER SOUTH ALONG THE EAST
COAST...ALLOWING A DRYING LOW LEVEL AIR MASS TO FILTER INTO THE
SOUTHEAST. BASED UPON THIS...OUR CURRENT POP FORECAST APPEARS TOO
PESSIMISTIC DURING THE LATTER HALF OF THE WEEK. WE HAVE BEGUN THE
PROCESS OF BACKING AWAY FROM HIGHER POPS...BUT WILL WAIT UNTIL A
CLEAR TREND BECOMES ESTABLISHED IN GUIDANCE BEFORE MAKING MORE
DRAMATIC CHANGES.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT...COLD WEDGE IN CONTROL FOR TODAY AND SHOULD BE ABLE TO
MAINTAIN ESE TO SE WINDS INTO THE EVENING. INCREASING WARM FLOW OVER
THE WEDGE IN CONJUNCTION WITH UPPER FORCING WILL LEAD TO
INCREASINGLY WIDESPREAD SHOWERS. AVBL GUIDANCE HAS BEEN GENERALLY
POOR WRT CIG HEIGHTS SO FAR THIS MRNG...BUT GIVEN UPSTREAM ACTIVITY
HAVE CAPPED GUIDANCE BLEND AT MVFR. SOME FEATURES WILL BE IN PLACE
TO ERODE THE WEDGE AS THE DAY PROGRESSES. HOWEVER GIVEN THE
CONTINUING PRECIP WILL ASSUME LATER GUIDANCE FOR EROSION TIMING.
SOME INSTABILITY TO CREEP IN AS THE WEDGE RETREATS AFTER SUNSET.
HENCE PROB30S FOR TSRA LATE TONIGHT.

ELSEWHERE...AHEAD OF PROMINENT UPPER SHORTWAVE TROUGH MIDLEVEL WINDS
WILL RAMP UP THIS MORNING OVER AFOREMENTIONED WEDGE. PRECIP
GENERALLY EXPECTED TO DROP VSBY ONLY TO MVFR...WITH CIG GUIDANCE
FAVORING IFR. HOWEVER GIVEN POOR EARLY MRNG PERFORMANCE AND UPSTREAM
OBS MVFR LOOKS LIKE A GOOD BET FOR TODAY. RESTRICTIONS ARE LIKELY TO
CONTINUE THRU THE PERIOD EVEN AFTER WEDGE DIMINISHES TONIGHT...WITH
LLVL MSTR PROFILES STAYING SATURATED. CURRENTLY EXPECT MOST SITES TO
HIT IFR THRESHOLD AFTER 00Z MON. THUNDER ALSO POSSIBLE EARLY THIS
MORNING NEAR THE TENN BORDER WITH INCOMING CONVECTIVE LINE...THOUGH
+RA AND LIGHTNING ARE THE ONLY THREATS. THUNDER MAY RETURN LATE THIS
AFTERNOON AND TONIGHT IN THE PIEDMONT WITH INSTABILITY POTENTIALLY
BEING REALIZED IN THE WAKE OF THE WEDGE.

OUTLOOK...AN UPPER LEVEL WAVE WILL CROSS THE REGION ON
MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND ASSOCIATED
RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE EACH MORNING
THROUGH MID WEEK.

CONFIDENCE TABLE...

            16-22Z        22-04Z        04-10Z        10-16Z
KCLT       HIGH  80%     MED   77%     LOW   55%     MED   63%
KGSP       HIGH  95%     MED   63%     MED   68%     MED   74%
KAVL       HIGH 100%     MED   60%     LOW   59%     LOW   50%
KHKY       HIGH 100%     HIGH  96%     LOW   57%     LOW   58%
KGMU       HIGH  83%     LOW   40%     MED   68%     MED   63%
KAND       LOW   57%     LOW   42%     HIGH  87%     HIGH  88%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR GAZ010-017-
     018.
NC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ048-
     051>053-058-059-062>065-507-509-510.
SC...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR SCZ001>007.

&&

$$
SYNOPSIS...JDL
NEAR TERM...NED
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY







AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 1252 PM CDT SUN APR 28 2013

.AVIATION...
MORNING STRATUS FINALLY BURNING OFF...AND VFR CONDITIONS ARE
EXPECTED THRU THE TAF PERIOD AT METROPLEX AIRPORTS. WACO FORECAST
SOUNDINGS SUGGEST RADIATION FOG IN THE MORNING...AND HAVE
INDICATED REDUCED VISIBILITIES NEAR SUNRISE. FOG SHOULD BURN OFF
QUICKLY WITH THE LAYER EXPECTED TO BE MUCH MORE SHALLOW THAN
TODAY. 84

&&

.UPDATE...
A PESKY BAND OF LOW CLOUDS HAVE BEEN MUCH SLOWER TO DISSIPATE
THAN WE HAD EXPECTED. THIS BAND OF CLOUDS ALONG THE I-20 CORRIDOR
FROM FORT WORTH EAST INTO LOUISIANA AND ALONG THE I-35 CORRIDOR
FROM DENTON TO JUST SOUTH OF WACO...SHOULD MIX OUT EARLY THIS
AFTERNOON. HAVE UPDATED THE CLOUD COVER AND HOURLY TEMPERATURE
FORECASTS TO ACCOUNT FOR THE CLOUDS. A WARM FRONT THAT EXTENDED
FROM NORTH OF LAMPASAS TO JUST SOUTH OF LUFKIN WILL MOVE NORTH
TODAY. LIGHT MOSTLY EAST TO SOUTHEAST WINDS TO THE NORTH OF THE
FRONT WILL BECOME SOUTHERLY AT AROUND 10 MPH AS THE FRONT MOVES
THROUGH. TEMPERATURES WILL STILL WARM INTO THE UPPER 70S TO MID
80S ACROSS THE REGION THIS AFTERNOON.

58

&&

.PREV DISCUSSION... /ISSUED 359 AM CDT SUN APR 28 2013/

REGIONAL RADAR MOSAIC SHOWS A BROAD AREA OF CONVECTION EXTENDING
FROM BRYAN SOUTHWEST ALONG THE TX GULF COAST TO CORPUS CHRISTI
EARLY THIS MORNING. 08Z /3AM/ SURFACE OBSERVATIONS SHOWED A
DIFFUSE FRONTAL BOUNDARY LOCATED JUST SOUTHEAST OF A LINE FROM
TEMPLE TO PALESTINE. THE BOUNDARY WAS MOST EVIDENT IN THERMAL AND
MOISTURE FIELDS AS LOW LEVEL WINDS HAVE ALREADY STARTED TO COME
AROUND TO THE SOUTHEAST TO THE NORTH OF THE FRONT. WATER VAPOR
SATELLITE IMAGERY SHOWED A COMPACT UPPER LOW OVER THE IN/IL BORDER
MOVING EAST-NORTHEAST EARLY THIS MORNING. WATER VAPOR IMAGERY ALSO
SHOWED A CYCLONIC SHEAR AXIS OR TROUGH TRAILING BEHIND THE UPPER
LOW TO THE SOUTHWEST. THIS TROUGH WAS LOCATED OVER THE CWA AS OF
08Z AND WAS MOVING SLOWLY SOUTHEAST. ALONG THE DIFFUSE FRONTAL
BOUNDARY...IR SATELLITE IMAGERY SHOWED MOSTLY CLOUDY SKIES WHICH
WAS HELPING TO KEEP TEMPERATURES IN THE LOWER TO MID 60S NEAR THE
FRONT. TO THE NORTHWEST OF THE FRONT THERE WAS A SHARP CUT-OFF IN
CLOUD COVER...ALLOWING TEMPERATURES TO FALL INTO THE 50S FOR MOST
OF NORTH TX EARLY THIS MORNING.

TODAY...THE UPPER LEVEL TROUGH IS EXPECTED TO SLOWLY MOVE
SOUTHEAST OF THE CWA TODAY...SPREADING WEAK LARGE SCALE FORCING
FOR SUBSIDENCE OVER THE AREA. SURFACE WINDS ARE EXPECTED TO RETURN
TO THE SOUTH TODAY WHICH MAY CAUSE THE WEAK FRONTAL BOUNDARY TO
LIFT NORTH ACROSS THE CWA THIS AFTERNOON. IT IS DIFFICULT TO
DETERMINE IF THIS WILL BE OF ANY CONSEQUENCE... BECAUSE THE RETURN
TO SOUTH WINDS UNDER MOSTLY SUNNY SKIES WILL MORE OR LESS
ELIMINATE ANY THERMAL GRADIENT/BAROCLINICITY ASSOCIATED WITH THE
FRONT.

BY DEFINITION THIS BOUNDARY WOULD NOT COUNT AS A FRONT ANYMORE
WITHOUT A DISCERNABLE THERMAL GRADIENT. HOWEVER...THERE WILL STILL
BE SOME SORT OF MOISTURE DISCONTINUITY ASSOCIATED WITH THE
BOUNDARY AS IT LIFTS NORTH TODAY...LIKELY RESULTING IN A SLIGHT
INCREASE IN RELATIVE HUMIDITY. NORMALLY THIS WOULD HAVE LITTLE
IMPACT ON THE FORECAST...BUT TODAY THE NAM AND RAP FORECAST
SOUNDINGS INDICATE THAT THE AFTERNOON INCREASE IN LOW-LEVEL
HUMIDITY IS SUFFICIENT TO RESULT IN AN ALMOST COMPLETE REMOVAL OF
THE CAP FROM THE FORECAST AREA DURING THE PEAK HEATING HRS OF THE
DAY. WITH NO CAP...IT IS POSSIBLE THAT SOME WEAK FORCING FOR
ASCENT COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS NORTH TX BY
LATE THIS AFTERNOON.

AT THIS TIME...LEFT THE FORECAST DRY BECAUSE OF A LACK OF
DISCERNABLE FOCUS FOR THUNDERSTORM INITIATION THIS AFTERNOON. THE
SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH IS EXPECTED TO BE
WEAK...BUT IN THE ABSENCE OF STRONG MESOSCALE FORCING FOR
ASCENT...THIS SHOULD BE SUFFICIENT TO KEEP US DRY DESPITE A NEARLY
UNCAPPED AFTERNOON THERMODYNAMIC ENVIRONMENT. OTHERWISE...WITH
MOSTLY SUNNY SKIES AND A RETURN TO SOUTH WINDS TODAY EXPECT
TEMPERATURES TO CLIMB INTO THE 80S FOR MOST LOCATIONS DESPITE THE
COOL START TO THE DAY THIS MORNING.

MONDAY AND TUESDAY...THE ECMWF/GFS/CANADIAN NOW ALL SHOW THE THAT
THE WESTERN EDGE OF OUR SOUTHEASTWARD MOVING TROUGH TODAY EVOLVES
INTO AN UPPER LEVEL CLOSED LOW OVER THE TX GULF COAST MONDAY INTO
TUESDAY. THIS WEAK UPPER LOW WILL LIKELY CAUSE CLUSTERS OF STORMS
TO DEVELOP EACH DAY ACROSS FAR SOUTH TX OR ALONG THE TX GULF
COAST...LIKELY WORKING TO REINFORCE THE UPPER LEVEL CIRCULATION
THROUGH THE PERIOD. DUE TO THE FORECAST POSITION OF THE UPPER LOW
TO OUR SOUTH...THIS FEATURE SHOULD ONLY REINFORCE UPPER LEVEL
SUBSIDENCE OVER THE CWA HELPING TO KEEP US DRY FOR EARLY THIS
WEEK. PERSISTENT SOUTHERLY FLOW WILL CONTINUE CAUSING SHALLOW GULF
MOISTURE TO REMAIN IN PLACE OVER THE CWA...BUT THUNDERSTORM
CHANCES SHOULD BE VERY LOW AS LONG AS THE UPPER LOW OVER THE GULF
COAST EVOLVES AS EXPECTED. AT ANY RATE...MOSTLY SUNNY SKIES AND
PERSISTENT SOUTHERLY FLOW WILL KEEP US ABOVE NORMAL FOR
TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S EACH DAY.

WEDNESDAY THROUGH FRIDAY...A POWERFUL UPPER LOW FROM THE GULF OF
ALASKA IS STILL EXPECTED TO MOVE SOUTHEAST OVER THE PLAINS
WEDNESDAY NIGHT INTO THURSDAY. THIS WILL SEND AN UNSEASONABLY
STRONG COLD FRONT SOUTH THROUGH THE PLAINS AND ACROSS NORTH TEXAS
LIKELY WEDNESDAY EVENING AND OVERNIGHT. AS LONG AS THE UPPER LOW
DIGS AS FAR SOUTH AS THE RED RIVER...WHICH IS ADVERTISED BY THE
OPERATIONAL ECMWF/GFS/CANADIAN...THERE SHOULD BE A NEARLY SOLID
LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANYING THE FRONT. THE FRONT
IS EXPECTED TO MOVE THROUGH THE AREA VERY FAST...SO OVERALL
RAINFALL AMOUNTS WILL LIKELY BE SMALL...BUT MOST LOCATIONS SHOULD
AT LEAST SEE SOME LIGHT RAIN AS THE FRONT MOVES THROUGH THE AREA.
BUMPED UP POPS INTO THE 40 TO 50 PERCENT RANGE ALONG AND BEHIND
THE FRONT AS A RESULT. DID NOT GO HIGHER AT THIS TIME BECAUSE OF
UNCERTAINTY REGARDING THE TIMING OF THE FRONT. WHILE OPERATIONAL
MODELS ARE CONSISTENT WITH THE FRONTAL PASSAGE RIGHT NOW...THE
FRONT IS STILL AT LEAST 84 HRS OUT...AND OUR MEDIUM RANGE GUIDANCE
IS NOTORIOUSLY BAD AT PREDICTING THE TIMING OF STRONG COLD FRONTS.
THEREFORE WILL CONTINUE TO REFINE POPS AND THE TIMING OF THE FRONT
IN FUTURE FORECASTS.

SEVERE WEATHER CHANCES OUT AHEAD OR ALONG THE FRONT DO NOT LOOK
GREAT PRIMARILY BECAUSE OF THE PROGGED FAST MOTION OF THE FRONT
THROUGH THE PLAINS. SOME SEVERE WEATHER MAY BE ADDED TO THE
FORECAST AS THE FRONT GETS CLOSER...BUT FOR NOW THE OVERALL
PATTERN DOES NOT SEEM TO SUPPORT A REGIONAL OUTBREAK OF SEVERE
STORMS...SO WILL NOT HIGHLIGHT ANY SEVERE WEATHER IN PRODUCTS AT
THIS TIME. TEMPERATURES BEHIND THE FRONT ARE EXPECTED TO BE VERY
COLD FOR EARLY MAY...WITH RECORD LOW TEMPERATURES LIKELY BEHIND
THE FRONT THURSDAY NIGHT. RECORD LOWS THURSDAY NIGHT WILL HELP
KEEP TEMPERATURES COOL HEADED INTO THE WEEKEND.

THIS WEEKEND...THE ECMWF IS LESS BULLISH WITH ITS FORECAST OF A
BLOCKING PATTERN THAT WOULD KEEP THE UPPER LOW ANCHORED IN THE
CENTRAL PLAINS FOR SEVERAL DAYS. THE NAEFS IS ALSO LEANING MORE
TOWARDS THE UPPER LOW MOVING NORTHEAST OUT OF THE REGION BY EARLY
NEXT WEEK. THAT SAID...THE NAEFS MEAN AND THE LAST EVENING RUN OF
THE ECMWF BOTH KEEP GENERAL TROUGHINESS OVER THE CENTRAL
CONUS...MEANING TEMPERATURES WILL LIKELY BE NEAR OR MAYBE SLIGHTLY
BELOW SEASONAL NORMALS. AFTER NEAR RECORD OR RECORD LOWS THURSDAY
NIGHT/FRIDAY MORNING...THERE IS LITTLE PLACE FOR THE TEMPERATURES
TO GO BUT UP. TEMPERATURES WILL MODERATE BACK TOWARDS SEASONAL
NORMALS THIS WEEKEND INTO EARLY NEXT WEEK...AND NOT JUST BECAUSE
MOS GUIDANCE TRENDS TOWARDS CLIMATOLOGY OUT ON DAY 7. THICKNESS
AND HEIGHT RISES WILL HELP USHER IN WARMER TEMPERATURES AS LONG AS
THE UPPER LOW DOES MOVE NORTHEAST OF THE PLAINS BY EARLY NEXT
WEEK. THE EXTENDED FORECAST IS DRY FOR NOW...HOWEVER WITH GENERAL
CYCLONIC FLOW IN PLACE THERE WILL UNDOUBTEDLY BE SOME SMALL
FEATURES THAT NECESSITATE THE INCLUSION OF PRECIPITATION DURING
THIS PERIOD IN FUTURE FORECASTS. AT THIS TIME THERE IS JUST NOT
ENOUGH CONSISTENCY TO PLACE POPS IN ONE PERIOD OVER ANOTHER...SO
LEFT THE FORECAST DRY WITH 10 POPS IN PLACE FOR SEVERAL DAYS.

CAVANAUGH



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  84  61  86  63  87 /  10   0   0   0   5
WACO, TX              84  58  84  60  86 /  10   0   0   0   5
PARIS, TX             79  55  83  58  84 /  10   0   0   0   5
DENTON, TX            83  58  87  59  87 /  10   0   0   0   5
MCKINNEY, TX          82  58  84  60  86 /  10   0   0   0   5
DALLAS, TX            83  62  86  64  87 /  10   0   0   0   5
TERRELL, TX           82  57  83  59  84 /  10   0   0   0   5
CORSICANA, TX         82  58  83  59  84 /  10   0   0   0  10
TEMPLE, TX            83  57  83  59  85 /  10   5   0   0   5
MINERAL WELLS, TX     83  58  86  59  87 /  10   0   0   0   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$






AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 558 PM CDT SUN APR 28 2013

.UPDATE...
ISSUED AT 558 PM CDT SUN APR 28 2013

CURRENTLY A NARROW LINE OF CONVECTION HAS INITIATED ALONG THE COLD
FRONT IN MINNESOTA FROM RUSH CITY TO MINNEAPOLIS AND ST JAMES.
LAPS ANALYSIS SHOWED MLCAPE VALUES OF 250-600 J/KG...MOSTLY RIGHT
ALONG THE FRONT. KMPX RADAR IMAGERY DOES SUGGEST THAT THE LINE OF
CONVECTION MAY HAVE JUMPED OFF THE FRONT RECENTLY...THOUGH.
MEANWHILE...OVER THE FORECAST AREA...SOME RIDGING HAS BUILT IN
ALOFT PER RAP ANALYSIS...HELPING TO CLEAR SKIES OUT.

PRECIPITATION CHANCES CONTINUE TO BE THE FOCUS TONIGHT. THE
28.12Z REGIONAL CANADIAN AND 28.19/20/21Z HRRR RUNS HAVE BEEN
DOING A GREAT JOB WITH THE CONVECTION ON THE FRONT. ALL OF THESE
MODELS SUGGEST A WEAKENING TREND AS THEY PUSH EAST THROUGH THE
EVENING. THIS MAKES SENSE AS THEY SEEM TO BE DIURNALLY ASSISTED
WITH THE CAPE THAT BUILT AHEAD OF THE FRONT. ONCE DIURNAL COOLING
TAKES PLACE...INSTABILITY WILL WANE AND THUS THE STORMS AS WELL.
PERHAPS A FEW MAY MAKE IT INTO NORTHWEST SECTIONS OF THE FORECAST
AREA...ENOUGH TO WARRANT 20-30 PERCENT CHANCES...LOWER THAN THE
PREVIOUS FORECAST. SEEING SOME OF THE CONVECTION JUMPING OFF THE
FRONT ALSO IS WORRISOME TO HOLD IT TOGETHER BECAUSE INSTABILITY
WANES PRETTY QUICK. THERE COULD BE A GENERALLY DRY PERIOD THEN
UNTIL LATE IN THE NIGHT...WHICH IS WHEN THE COLD FRONT SLIDES INTO
THE AREA. BEHIND THIS FRONT...TWO FORCING MECHANISMS SHOULD HELP
DEVELOP PRECIPITATION...

1. A SHORTWAVE OVER NORTHWEST WYOMING PUSHING EAST INTO EASTERN
SOUTH DAKOTA BY LATE IN THE NIGHT...YIELDING SOME DPVA DOWNSTREAM
INTO NORTHERN IOWA AND SOUTHERN MINNESOTA.
2. MID-LEVEL FRONTOGENESIS IN PLACE BEHIND THE FRONT. RADAR SHOWS
THIS FRONTOGENESIS ALREADY BY A BAND OF SHOWERS FROM NEAR ABERDEEN
SOUTH DAKOTA TO DULUTH MN.

THUS STILL HAVE KEPT SOME HIGHER PRECIPITATION CHANCES FOR LATE IN
THE NIGHT INTO MONDAY MORNING...ESPECIALLY OVER NORTHEAST IOWA
WHERE CONSENSUS EXISTS FROM ALL MODELS FOR PRECIPITATION TO OCCUR.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013

THE MAIN FOCUS FOR TONIGHT INTO MONDAY IS WITH A TWO TIERED SYSTEM
AND THE PRECIPITATION CHANCES THAT COME ALONG WITH IT. THE FIRST
WAVE APPROACHES THE REGION THIS EVENING IN THE FORM OF A SURFACE
COLD FRONT THAT IS CURRENTLY ANALYZED IN WESTERN MINNESOTA. MUCH
OF THE 28.12Z GUIDANCE ARE FORECASTING TOO HIGH OF SURFACE DEW
POINTS...IN THE LOW TO MID 50S WHEN CURRENT OBS SHOW MID
40S...WHICH IN TURN IS MAKING THE INSTABILITY IN THESE MODELS TOO
HIGH. THIS IS CAUSING A LOT OF THE GUIDANCE TO COME UP WITH A
LARGE AREA OF CONVECTION THAT DEVELOPS THIS EVENING AHEAD OF THE
FRONT AND BRINGS IT THROUGH THE REGION IN AN DIMINISHING FASHION
AS THE INSTABILITY WANES OVERNIGHT. THAT TREND IS OKAY...BUT AM
NOT VERY CONFIDENT THAT THIS CONVECTION WILL BE AS WIDESPREAD AS
GUIDANCE SUGGESTS. THE 28.12Z ARW EAST/WEST MODELS SEEM TO DO THE
BEST JOB AT LIMITING THE CLIMBING DEW POINTS AND KEEP 0-3KM MUCAPE
IN THE 200-400 J/KG RANGE OVERNIGHT AND MATCHES BEST TO THESE
THOUGHTS OF MORE SCATTERED THAN WIDESPREAD CONVECTION OVERNIGHT.
WITH JUST A FEW HUNDRED J/KG OF CAPE TO WORK WITH...HAVE LIMITED
THE THUNDER COVERAGE TO BEING ISOLATED TONIGHT. THERE IS SOME
INCREASING MID LEVEL WINDS AS THIS FRONT APPROACHES...SO SHEAR MAY
BE DECENT ENOUGH THAT...COMBINED WITH SOME LOW FREEZING
LEVELS...THERE COULD BE SOME SMALL HAIL THAT OCCURS WITH A FEW OF
THE STORMS BUT NOTHING THAT WOULD BE CONSIDERED SEVERE.

THE MAIN MID LEVEL TROUGH DIVES DOWN ACROSS THE REGION TOMORROW
MORNING AND IS EXPECTED TO DEVELOP A MORE WIDESPREAD AREA OF
CONVECTION ALONG THE WEAKENING SURFACE FRONT. THIS MID LEVEL
TROUGH IS CURRENTLY NOTED ON GOES WATER VAPOR IMAGERY EXTENDING
EAST TO WEST FROM SOUTHWEST ONTARIO INTO SOUTHEAST MONTANA. AS
THIS TROUGH SAGS SOUTHEAST TOMORROW...SOME DIFFERENCES ARISE
BETWEEN THE 28.12Z MESO AND SYNOPTIC SCALE MODELS. THE 28.12Z
NAM/GFS/ECMWF/GEM ALL SHOW SOME STRONG LOW LEVEL MOISTURE
TRANSPORT NOSING UP INTO EASTERN IOWA BY LATE MORNING THAT ALSO
BRING SURFACE DEW POINTS UP INTO THE 60S AHEAD OF THE SURFACE/LOW
LEVEL LOW. THIS BRINGS SFC/0-3KM MUCAPE UP TO ABOVE 2000 J/KG AND
DEVELOPS A WIDESPREAD AREA OF CONVECTION ALONG THE NOSE OF THE LOW
LEVEL JET. MEANWHILE...28.12Z ARW/NMM ARE MUCH MORE TAME WITH THE
MOISTURE RETURN/DEW POINTS/INSTABILITY AND CONVECTIVE DEVELOPMENT.
HAVE KEPT THE LIKELY PRECIPITATION CHANCES GOING FOR NORTHEAST
IOWA/SOUTHWEST WISCONSIN TOMORROW WHERE THIS CONVECTION IS A BIT
MORE CERTAIN...BUT THINK THAT THE SYNOPTIC MODELS ARE A TAD
OVERDONE. IF THE MOISTURE RETURN CAN DEVELOP AS ADVERTISED ON
THESE SYNOPTIC MODELS...WILL HAVE TO WATCH FOR A BRIEF PERIOD OF
SEVERE STORMS THAT COULD PRODUCE SOME LARGE HAIL/GUSTY WINDS.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013

THE 28.12Z GUIDANCE REMAINS STUBBORN WITH NO DIFFERING TRENDS
NOTED BETWEEN THIS RUN AND THE 28.00Z RUN FOR A COLD FRONT THAT
WILL MOVE THROUGH ON TUESDAY. AHEAD OF THIS FRONT
ON MONDAY NIGHT...THE LOW LEVEL JET/MOISTURE TRANSPORT WILL PUSH
BACK TO THE NORTH AHEAD OF THE FRONT AND COULD SPARK OFF SOME
CONVECTION AS IT LIFTS NORTHWARD. FOR TUESDAY...THE 28.12Z ECMWF
REMAINS THE SLOW OUTLIER WITH THE EASTWARD PROGRESSION OF THE
SURFACE COLD FRONT ON TUESDAY AND PRESENTS THE WARMEST SOLUTION
FOR TEMPERATURES. BY 00Z WEDNESDAY...THE 28.12Z NAM/GFS BOTH HAVE
THIS FRONT INTO NORTHWEST ILLINOIS WHILE THE ECMWF STILL HAS IT
BACK IN NORTHWEST WISCONSIN/JUST CLEARING SOUTHEAST MINNESOTA.
WITH LOW LEVEL MOISTURE TRANSPORT INCREASING AHEAD OF THIS FRONT
ON TUESDAY AND DECENT LOW LEVEL LIFT ALONG THE FRONT...SOME SEVERE
WEATHER IS POSSIBLE IN THE WARM SECTOR TUESDAY. WHERE THAT WARM
SECTOR IS ALIGNED BY MID AFTERNOON IS UNCERTAIN STILL...BUT WILL
HAVE TO WATCH FOR WHICH WAY THIS FRONT TRENDS. DUE TO THERE NOT
BEING MUCH IN THE WAY OF CHANGES IN THE GUIDANCE...HAVE NOT MADE
MANY ADJUSTMENTS TO THE GOING FORECAST OVER THIS PERIOD.

AFTER THIS COLD FRONT MOVES THROUGH BY TUESDAY NIGHT IT WILL THEN
STALL OUT TO THE EAST OF THE REGION AS A MID TO UPPER LEVEL TROUGH
AMPLIFIES ACROSS THE CENTRAL US TOWARD THE MIDDLE OF THE WEEK.
THIS TROUGH GETS CUT OFF FROM THE FLOW WITH THE CORE OF THE LOW
SITTING RIGHT OVER THE UPPER MISSISSIPPI RIVER VALLEY THROUGH NEXT
WEEKEND. STRONG FORCING WILL DEVELOP ON WEDNESDAY IN RESPONSE TO
A STRENGTHENING LOW TO MID LEVEL BAND OF FRONTOGENESIS THAT FORMS
TO THE WEST OF THE SURFACE FRONT. WHILE THE 28.12Z ECMWF CONTINUES
TO BE AN OUTLIER WITH A WARMER SOLUTION FROM 700MB DOWN TO THE
SURFACE ON WEDNESDAY AND WANTS TO KEEP THE PRECIPITATION AS
MAINLY RAIN TO BEGIN...IT DOES APPEAR TO BE COMING AROUND TO BEING
COLD ENOUGH TO PRODUCE ALL SNOW FROM WEDNESDAY NIGHT INTO EARLY
THURSDAY. THIS IS ESPECIALLY THE CASE ACROSS SOUTHEAST MINNESOTA
AND NORTHEAST IOWA WHERE SOME SIGNIFICANT SNOW RATES AND
ACCUMULATIONS ARE POSSIBLE. 28.12Z GFS THERMAL PROFILES SHOW THAT
THE MAIN QUESTION IS WITH SURFACE TEMPERATURES AND HOW MUCH THEY
WILL COOL AS THE PRECIPITATION COMMENCES ON WEDNESDAY. THE HIGHEST
CONFIDENCE FOR ANY SNOW ACCUMULATION AT THIS POINT IS WEDNESDAY
NIGHT INTO THURSDAY MORNING AS THE COLDEST LOW LEVEL AIR COMES IN.
CURRENT FORECAST TEMPERATURES FOR WEDNESDAY INTO THURSDAY MAY END
UP BEING TOO HIGH...BUT FOR NOW HAVE DONE A SEMI-BLEND OF THE
28.12Z GFS/ECMWF.

BEYOND THIS FEATURE...THE 28.12Z GFS IS FASTER WITH CLEARING OUT
THE PRECIPITATION ON THURSDAY COMPARED TO THE ECMWF AND GEM WHICH
LINGER THE FRONTOGENETIC BAND OVER THE REGION THROUGH THE REST OF
THE WEEK AS THE MID LEVEL LOW GETS CUT OFF FROM THE FLOW. THIS MID
LEVEL AND SURFACE LOW RETROGRADE BACK INTO IOWA/MISSOURI BY NEXT
WEEKEND...WHICH MAY HELP TO BRING SOME SLIGHTLY WARMER AIR BACK
INTO THE REGION. OVERALL...EXPECTING PERIODS OF PRECIPITATION AS
THIS LOW SITS AND SPINS WITH SHORTWAVE TROUGHS ROTATING AROUND IT
THROUGH NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 28 2013

A COLD FRONT WILL MOVE SOUTHEAST INTO THE AREA TONIGHT AND THEN
STALL NEAR THE INTERSTATE 90 CORRIDOR. THIS FRONT WILL BE THE
FOCUS FOR THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. THE BEST
CHANCE OF THUNDERSTORMS LOOKS TO BE FROM 29.03Z TO 29.09Z AT KRST...
AND FROM 29.06Z AND 29.10Z AT KLSE. AS THE LOW LEVELS SLOWLY
SATURATE...VISIBILITIES WILL BECOME MVFR. THIS SHOULD OCCUR AROUND
29.09Z AND THEN CONTINUE THROUGH THE REMAINDER OF THE MORNING.
HOW LOW THE CEILINGS WILL FALL ALONG AND IN THE WAKE OF THE FRONT
IS STILL UNCERTAIN. THE BUFKIT SOUNDINGS SUGGEST THAT CEILINGS
WILL BE IFR/MVFR AT KRST AND MVFR AT KLSE AFTER 29.09Z...BUT THESE
MODELS ALSO SHOW A MUCH LARGER AREA OF PRECIPITATION THAN THE MESO
MODELS. THIS AREAL EXTENT OF THE PRECIPITATION WILL GREATLY AFFECT
THE CEILINGS. AS A RESULT...JUST INTRODUCED A BROKEN MVFR DECK AT
KRST AND LEFT THE CEILINGS VFR AT KLSE.


&&

.HYDROLOGY...
ISSUED AT 327 PM CDT SUN APR 28 2013

POTENTIAL EXISTS FOR SOME HEAVY RAINFALL THIS WEEK AS A SYSTEM
STALLS OUT ACROSS THE REGION TOWARD MID WEEK. THERE IS SOME
QUESTION ABOUT WHAT THE PRECIPITATION TYPE WILL BE...BUT THE
FORECAST GUIDANCE IS SUGGESTING RAINFALL AMOUNTS OF OVER AN INCH
BY THE END OF THE WEEK. SHOULD THIS PRECIPITATION FALLS AS
RAIN...THERE COULD BE AN INCREASE IN LOCAL RIVER LEVELS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

UPDATE...AJ
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
HYDROLOGY...HALBACH