Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 261325
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
925 AM EDT WED AUG 26 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE PROVIDE DRY WEATHER INTO THURSDAY.
AS THE HIGH SHIFTS TO THE MID ATLANTIC...THE FLOW WILL
TURN MORE EASTERLY INCREASING MOISTURE OVER TIME INTO
THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EDT WEDNESDAY...

HIGH PRESSURE WILL BUILD EAST ACROSS THE REGION TODAY AND TONIGHT.
MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND CLOUD COVER FOR
THIS MORNING INTO THIS AFTERNOON. HIGH TEMPERATURES WILL WARM INTO
THE UPPER 60S IN THE MOUNTAINS TO THE MID 80S IN THE PIEDMONT.

AS OF 711 AM EDT WEDNESDAY...

A FEW MORE CLOUDS EVIDENT IN THE EASTERN HALF OF THE CWA. HAVE
INCREASED SKY COVER TO ACCOUNT FOR THIS...BUT OVERALL WILL STILL
BE MOSTLY SUNNY FOR MOST OF THE DAY.

PREVIOUS EARLY MORNING DISCUSSION...

PUSH OF MOISTURE AT 8H ANGLING TOWARD SE WV...WITH 00Z NAM APPEARING
TO CATCH THIS A LITTLE BETTER THAN OTHER MODELS. AM LEANING TOWARD
THE NAM IN TERMS OF SKY COVER TODAY...SO WILL WORK MORE CLOUDS EARLY
IN SE WV/FAR SW VA WITH MAINLY CLEAR TO PARTLY CLOUDY ELSEWHERE. AS
THE DAY PROGRESSES THE CLOUDINESS IN SE WV TO SCATTER OUT.

MODELS DIFFER TONIGHT...WITH FRONTAL WAVES ALONG THE SOUTHEAST
COAST. THE GFS SHOWING SOME OVERRUNNING MOISTURE ENTERING
SOUTHSIDE VA/NW NC PIEDMONT...PRINTING OUT SOME SHOWERS. SEEMS
OVERDONE AND FORECAST WILL KEEP IT DRY WITH STRONG HIGH PRESSURE
BUILDING IN FROM THE GREAT LAKES.

HIGHS TODAY WILL BE A FEW DEGREES BELOW NORMAL...THOUGH SUNSHINE
SHOULD WARM IT UP FAST IN THE DRIER AIR MASS. TEMPS RANGING FROM THE
LOWER TO MID 70S ACROSS THE MOUNTAINS...TO LOWER TO MID 80S FROM THE
ROANOKE VALLEY EAST TO THE PIEDMONT.

TONIGHT...TEMPS A DEGREE OR TWO MILDER THAN TONIGHT WITH FLOW
TURNING MORE NORTHEAST. LOWS WILL RANGE FROM LOWER TO MID 50S
MOUNTAINS...TO AROUND 60 EAST.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 400 AM EDT WEDNESDAY...

UPPER-LEVEL TROUGH REMAINS IN PLACE AT THE BEGINNING OF THE
PERIOD BEFORE STARTING TO LIFT NORTH INTO A MORE ZONAL FLOW
PATTERN FRIDAY AFTERNOON. SURFACE HIGH PRESSURE BEGINS TO BUILD
INTO THE OHIO RIVER VALLEY DURING THE EARLY PART OF THE
PERIOD...MAINTAINING NORTHERLY FLOW INTO THE REGION THROUGH EARLY
FRIDAY MORNING. COOLER/DRIER AIR WILL ACCOMPANY THE FLOW...KEEPING
PRECIPITATION AT BAY AND MAINTAINING CLEAR SKIES...COMFORTABLE DEW
POINTS AND SLIGHTLY BELOW NORMAL TEMPERATURE VALUES.

FLOW TURNS EASTERLY FRIDAY AND SATURDAY AS THE SURFACE HIGH STALLS
WHILE PIVOTING AROUND THE DELMARVA PENINSULA. SLOWLY... ATLANTIC
MOISTURE WILL BEGIN TO MIX FURTHER INTO THE REGION FROM EAST TO
WEST...BRINGING INCREASING AFTERNOON CLOUD COVER AND THE RETURN
OF ISOLATED SHOWER/STORM ACTIVITY. ANY SHOWERS THAT DO FORM WILL
BE LOCATED ALONG THE EASTERN SLOPES OF THE BLUE RIDGE...ESPECIALLY
TOWARD THE SOUTHERN HALF OF THE FORECAST AREA FARTHER AWAY FROM
THE HIGH PRESSURE CENTER.

A BIT OF UNCERTAINTY REMAINS SURROUNDING THE LOCATION AND STRENGTH
OF THE HIGH...AND HOW THAT WILL AFFECT THE MOISTURE RETURN POTENTIAL
THROUGH THE PERIOD. GFS CONTINUES TO SHOW MUCH HIGHER POP VALUES
SATURDAY AFTERNOON TO SUNDAY...WHILE OTHER MODELS KEEP THE REGION
MOSTLY DRY. FOR NOW...KEEPING ISOLATED TO SCATTERED SHOWERS/STORMS
POSSIBLE...ESPECIALLY IN AREAS OF LIKELY TERRAIN ENHANCEMENT.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 1245 PM EDT TUESDAY...

MEAN UPPER RIDGING ACROSS THE REGION WILL BE INFILTRATED BY SLOW
MOVING SHORTWAVE ENERGY THAT WILL DROP SOUTHEAST AND ATTEMPT TO
LOWER 5H HEIGHTS ACROSS THE MID ATLANTIC BY EARLY NEXT WEEK. TO
WHAT DEGREE THIS OCCURS REMAINS UNCERTAIN ESPECIALLY GIVEN
POTENTIAL TO SEE RIDGING STRENGTHEN OVER THE SOUTHEAST STATES WITH
APPROACH OF ERIKA FROM THE SOUTHEAST EARLY NEXT WEEK. HOWEVER DOES
APPEAR THAT SURFACE HIGH PRESSURE WILL BASICALLY REMAIN ENTRENCHED
OVER THE AREA...BETWEEN THE RESIDUAL FRONT OFFSHORE THE
SOUTHEAST...AND MID LEVEL WEAKNESS TO THE NW. GRADUAL RETURN OF
MOISTURE PER THE WEAK FLOW TURNING MORE SOUTHERLY AHEAD OF ANY
UPSTREAM FEATURES AT TIMES...AND SEEN IN LATEST MODEL
PWATS...SUPPORTS SOME INCREASE IN DAILY DIURNAL CONVECTION THROUGH
MOST OF THE PERIOD. THIS PRIMARILY ACROSS THE RIDGES WHERE AIDED
BY OROGRAPHICS...WITH BEST CHANCES PERHAPS SUNDAY GIVEN SOME
COOLING ALOFT...AND POSSIBLE REMNANT WAVE OF DANNY SLIDING UP
ALONG THE FRONT PER GFS BEFORE UPPER RIDGING STRENGTHENS AGAIN
EARLY NEXT WEEK.

OTHERWISE AN OVERALL PERSISTENCE FORECAST WITH PC WEST TO MOSTLY SUNNY
EAST DURING THE DAY INCLUDING ISOLATED TO WIDELY SCATTERED
CONVECTION...THEN MOSTLY CLEAR OVERNIGHT. WILL BECOME MORE HOT/HUMID
THROUGH THE PERIOD GIVEN MOISTURE ADVECTION AND WARMING ALOFT WHICH
SHOULD PUSH HIGHS CLOSER TO 90 EAST WITH MOSTLY 80S ELSEWHERE FOR NOW.

&&

.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AS OF 712 AM EDT WEDNESDAY...

FOG DID NOT REALLY MATERIALIZE AS EXPECTED AND EXPECT VFR THROUGH
THE REST OF THE TAF PERIOD. DID NOT ALLOW FOR SOME FOG AT LWB/BCB
LATE TONIGHT...THOUGH CONFIDENCE IS LOW ON HOW LOW THE SFC VSBY
GETS.

EXTENDED AVIATION DISCUSSION...

EXPECT A MAINLY VFR FORECAST INTO SUNDAY. MOISTURE GRADUALLY
INCREASES BY THE WEEKEND WITH ISOLATED TO SCATTERED CONVECTION
POSSIBLE. EXCEPTION TO THE VFR WILL BE THE TYPICAL LATE NIGHT FOG
THREAT OVER LWB/BCB THROUGH THE PERIOD.

&&

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

&&

$$
SYNOPSIS...KK/WP
NEAR TERM...KK/WP
SHORT TERM...JM/NF
LONG TERM...JH
AVIATION...DS/WP



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