Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 252325
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
725 PM EDT MON APR 25 2016

.SYNOPSIS...
HIGH PRESSURE ALONG THE NORTH CAROLINA COAST WILL MOVE SOUTHEAST
TODAY. LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY WILL MOVE
EAST TODAY WITH A COLD FRONT EXTENDING FROM NEW YORK TO KANSAS BY
TUESDAY MORNING. THIS FRONT WILL MOVE SOUTH THEN WILL TRAIL FROM
THE NORTH CAROLINA TO THE MID MISSISSIPPI VALLEY ON WEDNESDAY AND
THURSDAY.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 700 PM EDT MONDAY...

SURFACE HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT TO ALLOW A
MOISTER SOUTHWEST FLOW OVER THE MID ATLANTIC. A COLD FRONT
REMAINS TO THE NORTH...BUT A WAVE ALONG THIS FRONT SHOULD PUSH A
WEAK TROUGH OVER THE MOUNTAINS ON TUESDAY MORNING...BEFORE
STALLING IT OVER THE PIEDMONT BY THE AFTERNOON. THIS SITUATION
SHOULD INCREASE THE CHANCES FOR A FEW SHOWERS AND THUNDERSTORMS
LATER IN THE DAY. MILD TEMPERATURES SHOULD CONTINUE FOR THE NEXT
24 HOURS...WITH LOWS TONIGHT IN THE LOWER 50S TO THE LOWER
60S...AND HIGHS FOR TUESDAY IN THE UPPER 70S TO THE MID 80S.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 245 PM EDT MONDAY...

UNSETTLED WEATHER IS EXPECTED DURING THIS PORTION OF THE
FORECAST. AT THE SURFACE...A COLD FRONT PUSHES SOUTH INTO OUR
FORECAST AREA BY WEDNESDAY MORNING IN RESPONSE TO A DEEPENING
UPPER TROF IN NEW ENGLAND AND SOUTHEAST CANADA. WITH THE MEDIUM
RANGE MODELS INDICATING A WEAK UPPER LEVEL WAVE PASSING
THROUGH...KEPT POPS IN PLACE THROUGH THE NIGHT AND LEANED TOWARD
THE WARMER SIDE OF GUIDANCE WITH ANTICIPATED CLOUD COVER.

FOR WEDNESDAY...THIS SFC FRONT WILL STALL SOMEWHERE ACROSS OR
JUST SOUTH OF THE FORECAST AREA. THE 00Z ECMWF...AND TO A LESSER
EXTENT...THE 12Z NAM AND 09Z SREF MODELS MORE AGRESSIVE WITH
DEVELOPING THE WEDGE COMPARED TO THE GFS. SREF 2M TEMP PLUMES SHOW
LOW CONFIDENCE FOR TEMPS ON WEDNESDAY WITH A WIDE RANGE OF
POSSIBILITIES. LEANED TOWARD THE MAJORITY OF MODELS AND KNOCKED
TEMPS DOWN A FEW DEGREES IN THE EAST...WHICH MAY NOT BE COLD
ENOUGH...AND KEPT CHANCES FOR THUNDER ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA.

PRECIPITATION MAY BE FAIRLY WIDESPREAD ON WEDNESDAY AS LOW LEVEL
CONVERGENCE INCREASES ALONG THE SFC BOUNDARY...AHEAD OF A
DEVELOPING SFC WAVE...AND UPPER LEVEL DIVERGENCE INCREASES THROUGH
THE DAY IN ADVANCE OF THE CENTRAL PLAINS UPPER LOW. STILL NO
FLOODING CONCERNS ANTICIPATED WITH RAINFALL RATES NOT EXPECTED TO
BE EXCESSIVE AND DRY ANTECEDENT CONDITIONS.

SHOWERS...ALONG WITH THUNDERSTORMS OUTSIDE THE WEDGE...WILL AGAIN
BE FOUND WEDNESDAY AND ESPECIALLY THURSDAY AS MODELS GENERATE GOOD
LIFT IN ADVANCE OF AN UPPER LEVEL SHORTWAVE TRACKING THROUGH THE
GREAT LAKES INTO THE OHIO VALLEY...ALONG WITH PWATS 2-3 STANDARD
DEVIATIONS ABOVE NORMAL. THE NAM MODEL APPEARS TO BE THE OUTLIER
WITH ITS MUCH FASTER SOLUTION. HIGH TEMPERATURE FORECAST AGAIN
WILL BE TRICKY DEPENDING IF/WHEN THE LOW LEVEL WEDGE ERODES.
UNDERCUT FORECAST HIGHS THURSDAY BY SEVERAL DEGREES IN VA PIEDMONT
AND SOUTHERN SHENANDOAH VALLEY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 245 PM EDT MONDAY...

WEAK UPPER RIDGING DEVELOPING LATE FRIDAY THROUGH SATURDAY WILL
KEEP PRECIP CHANCES CONFINED TO ISOLATED/WIDELY SCATTERED IN
COVERAGE. AT THE SFC...12Z ECMWF KEEPS WEDGE IN PLACE THROUGH
SATURDAY. WHILE TEMPS WERE BROUGHT DOWN A COUPLE OF DEGREES DURING
THIS TIME...THESE FORECAST VALUES STILL MAY BE TOO WARM.

 HOWEVER...BETTER CHANCES FOR MORE WIDESPREAD PRECIPITATION
ARRIVE LATER SUNDAY INTO MONDAY...DEPENDING ON THE ARRIVAL OF AN
OPENING UPPER LOW MOVING THROUGH THE OHIO VALLEY. AS IT TYPICAL
FOR THE LONG RANGE MODELS...THERE IS DISAGREEMENT IN THE TIMING
AND TRACK OF THIS SYSTEM...BUT INDIVIDUAL GEFS ENSEMBLE MEMBERS
SUGGEST THE BEST CHANCES FOR PRECIPITATION WILL BE LATE SUNDAY
INTO EARLY MONDAY...AND THIS IS THE TIME PERIOD WHERE THE POPS ARE
HIGHEST.

TEMPS ARE EXPECTED TO BE BELOW NORMAL EARLY WITH THE WEDGE IN
PLACE TO NEAR NORMAL LATER IN THE LONG TERM PERIOD.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 725 PM EDT MONDAY...

VFR CONDITIONS CONTINUE THROUGH THE TAF FORECAST PERIOD. SURFACE AND
LOW LEVEL WINDS WILL BE LIGHT FROM THE SOUTH OR SOUTHEAST THIS
EVENING...BUT TRANSITION TO LIGHT SOUTHWEST BY SUNRISE TUESDAY.

LOW PRESSURE WILL TRACK FROM THE OHIO VALLEY TO THE MID ATLANTIC
REGION TUESDAY MORNING AND BRING LOWERING CLOUDS AND A WIND SHIFT
TO THE WEST ACROSS THE MOUNTAINS. THIS TROUGH WILL STALL OVER THE
PIEDMONT TUESDAY WHILE KEEPING A SOUTHWEST WIND. DESPITE LOWERING
CEILINGS...LEVELS WILL REMAIN VFR. WITH A BOUNDARY IN THE AREA AND
MOISTURE ON THE INCREASE...SCATTERED SHOWERS AND THUNDERSTORM ARE
POSSIBLE TUESDAY AFTERNOON...MAINLY ACROSS THE MOUNTAINS. BY THE
LATE MORNING OR EARLY AFTERNOON...SURFACE GUSTS WILL BE IN THE 15
TO 20 KT RANGE.

EXTENDED AVIATION DISCUSSION...

AS OF 120 PM EDT MONDAY...

A WEAK COLD FRONT WILL SLOWLY ARRIVE FROM THE NORTH BY TUESDAY NIGHT.
THIS FRONT COULD STALL OVERHEAD ON WEDNESDAY...BEFORE A STRONGER
COLD FRONT ENTERS FROM THE WEST TO PUSH THE WEAKER FRONT OFFSHORE.
DURING THIS TIME PERIOD...SCATTERED SHOWERS WITH A FEW AFTERNOON
THUNDERSTORMS APPEAR LIKELY. THE GREATEST CHANCE OF RAIN AND
MVFR/IFR CONDITIONS COULD ACCOMPANY THE STRONGER COLD FRONT ON
THURSDAY. SOME CLEARING SHOULD TAKE PLACE DURING FRIDAY...ALTHOUGH
A FEW MOUNTAIN SHOWERS AND MVFR CLOUDS ARE POSSIBLE.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...RCS
NEAR TERM...PW/RCS
SHORT TERM...PH
LONG TERM...PH
AVIATION...DS/RCS


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