Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 310522
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
122 AM EDT FRI JUL 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL EXTEND EASTWARD FROM THE LOWER MISSOURI VALLEY
INTO THE MID ATLANTIC TODAY PROVIDING LOWER HUMIDITY. THIS HIGH
WILL STAY OVER MOST OF REGION THIS WEEKEND. A COUPLE OF UPPER
DISTURBANCES MAY BRING A FEW SPOTTY SHOWERS TO THE MOUNTAINS LATE
SATURDAY OR SUNDAY...BUT THE MAJORITY OF OUR AREA WILL STAY DRY.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 112 AM EDT FRIDAY...

DRY AIR KEEPS FILTERING IN BEHIND FRONT AS DEWPOINTS HAVE DROPPED
INTO THE MID TO UPPER 50S ACROSS THE MOUNTAINS...AND EVEN TO 60 AT
LYH. ALL SHOWERS HAVE EXITED THE CWA AND NOT EXPECTING ANY THE
REST OF THE NIGHT AS SKIES STAY MAINLY CLEAR AND MOONLIT. SOME
PATCHY FOG WILL FORM IN THE RIVER VALLEYS IN THE MOUNTAINS. LOWS
STILL LOOK ON TRACK FOR UPPER 50S MOUNTAINS TO UPPER 60 SOUTHSIDE
VA/ NW NC PIEDMONT.

PREVIOUS VALID DISCUSSION...

HIGH PRESSURE BUILDS EAST FROM THE CENTRAL PLAINS FRIDAY. THE
HIGH CENTER WILL BRING WITH IT DRIER AIR...PUSHING DEWPOINTS INTO
THE 50S AND LOWER 60S. THE LOWER RELATIVE HUMIDITIES WILL BE A
WELCOME CHANGE FOR MANY. HIGH TEMPERATURES FRIDAY AFTERNOON WILL
BE IN THE MID 70S IN THE NORTHWEST MOUNTAINS TO AROUND 90 DEGREES
IN THE PIEDMONT.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 215 PM EDT THURSDAY...

A QUIET AND RATHER COMFORTABLE PERIOD LOOKS IN STORE UNDER BROAD UPPER
TROFFINESS ENHANCED VIA SURFACE HIGH PRESSURE BUILDING OVERHEAD THROUGH
THE WEEKEND. THIS SHOULD RESULT IN MAINLY SUNNY WARM DAYS AND
CLEAR/PLEASANT NIGHTS GIVEN DRIER DEWPOINTS AND SUBSEQUENT LOWER
HUMIDITY THROUGH AT LEAST SUNDAY. ONLY EXCEPTIONS COULD BE WITH MORE
CLOUDS AND POSSIBLY A FEW LIGHT SHOWERS NW UNDER SLIGHTLY BETTER
UPSLOPE LATE SATURDAY...AND THEN PERHAPS OVER THE WESTERN HALF SUNDAY
EVENING WITH A PASSING MID LEVEL SHORTWAVE. HOWEVER GIVEN PROGGED
DRYNESS AND LIKELY ISOLATED NATURE TO ANY SHOWERS OPTING TO LEAVE OUT
ANY POPS OR SHOWER MENTION FOR NOW.

TEMPS LOOK TO REMAIN QUITE PERSISTENT THROUGH THE PERIOD WITH WEAK
DOWNSLOPE/HEATING OF DRY AIR ALLOWING HIGHS TO REMAIN IN THE 85-90
RANGE EAST...AND MOSTLY LOW/MID 80S MOUNTAINS DESPITE THE COOLER/DRIER
AIRMASS. BETTER IMPACT OF THE DRY AIR TO BE FELT DURING THE OVERNIGHTS
WITH LOWS IN THE 50S VALLEYS AND LOW/MID 60S ELSEWHERE. COOLEST NIGHT
AT THIS POINT LOOKS TO BE EARLY SUNDAY WITH THE PASSING OF THE 85H
TROUGH...AND HIGH PRESSURE ABOUT OVERHEAD POSSIBLY ALLOWING A FEW 40S
IN THE DEEPEST NW VALLEYS PENDING ANY RIVER FOG LATE.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 1230 PM EDT THURSDAY...

MEAN 5H TROUGH TO REMAIN ACROSS THE MID ATLANTIC REGION THROUGH MUCH OF
NEXT WEEK WITH STEADY NW FLOW ALOFT BETWEEN UPPER LEVEL LOW PRESSURE
WELL TO THE NORTH AND STRONG RIDGING OVER THE SW STATES. THIS SHOULD
ALLOW FOR AN OVERALL PERSISTENCE TYPE FORECAST THROUGH THE EXTENDED
WITH TOLERANT HUMIDITY LEVELS ALONG WITH LOWS MOSTLY IN THE 60S AND
HIGHS 80S TO LOWER 90S. COVERAGE OF SHOWERS AND STORMS ALSO LIKELY
LIMITED PENDING PROGRESSION OF THE NEXT POSSIBLE COOL SURGE LATE IN THE
PERIOD. HOWEVER WILL ALSO HAVE TO WATCH LINGERING MOISTURE WITH THE
RESIDUAL FRONT NEAR THE COAST WHICH COULD BE LIFTED BACK NORTH BY
APPROACH OF WEAK IMPULSES ALOFT ESPECIALLY EARLY NEXT WEEK. THIS ALONG
WITH HEATING MAY BE ENOUGH TO SPARK ISOLATED CONVECTION MAINLY SOUTH
MONDAY...AND ALONG A PASSING SHORTWAVE TROUGH AXIS CROSSING FROM THE NW
TUESDAY...BUT LOW POPS AT BEST BOTH DAYS.

UPPER TROUGH JUST NORTH OF THE LAKES WILL DEEPEN AGAIN BY MIDWEEK AS
MORE SHORTWAVE ENERGY ROTATES THROUGH AND SLIDES AN ASSOCIATED COLD
FRONT SOUTH TOWARD/INTO THE REGION. HOWEVER MODELS DISAGREE ON THE
AMPLITUDE OF THE DIGGING TROUGH WITH THE GFS MOST AGGRESSIVE WHILE
OTHER SOLUTIONS SLOWER/WEAKER WHILE MAINTAINING MORE CONVECTION ALONG
THE BOUNDARY. FOR NOW WILL GO WITH A WEAKER/SLOWER SCENARIO BUT LEAN
TOWARD THE GFS IN DRIVING THE COOL ADVECTION IN BY THE END OF THE
PERIOD SINCE IT HAS BEEN BEST OF LATE.

&&

.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
AS OF 119 AM EDT FRIDAY...

VFR TO PREVAIL OVER TAF SITES THIS PERIOD. EXCEPTION WILL BE LWB
WHERE SOME FOG COULD FORM THIS MORNING PRIOR TO DAWN...THOUGH WILL
BE A RACE BETWEEN TEMP/DEWPOINT.

EXTENDED AVIATION FORECAST...

MAINLY VFR THIS WEEKEND WITH HIGH PRESSURE IN PLACE. A FEW UPPER
DISTURBANCES MAY BRING A FEW VFR CIGS TO THE MOUNTAINS LATER
SATURDAY INTO SUNDAY. THE THREAT OF SHOWERS WILL BE LOW THOUGH A
BACKDOOR FRONT MAY ALLOW FOR SOME AGAIN LATER MONDAY OR TUESDAY.
WITH SUSTAINED WINDS STAYING LIGHT TO CALM AT NIGHT AND MAINLY
CLEAR SKIES...THE FOG THREAT WILL EXIST IN THE TYPICAL PREDAWN
HOURS AT LWB/BCB BY EARLY NEXT WEEK.

&&

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

&&

$$
SYNOPSIS...WP
NEAR TERM...AMS/KK/WP
SHORT TERM...JH
LONG TERM...JH
AVIATION...WP



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