National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 241402
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1002 AM EDT FRI MAY 24 2013

.SYNOPSIS...
-- Changed Discussion --
COOLER AND DRIER AIR WILL PUSH IN ON NORTHWEST WINDS TODAY. HIGH
PRESSURE BUILDING IN WITH THE FRONT WILL KEEP THE UNSEASONABLY
COOL AIR IN THE AREA THROUGH THE WEEKEND. A WARM FRONT WILL LIFT
NORTH FROM THE GULF COAST EARLY NEXT WEEK...FOLLOWED BY STRONG
HIGH PRESSURE BRINGING MORE SUMMER LIKE WEATHER BY MID TO LATE
WEEK.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 950 AM EDT FRIDAY...

COLD FRONT NOW LOCATED EAST OF US WITH COOLER AND DRIER AIR
LAGGING BEHIND ACROSS THE PIEDMONT. FEW SHOWERS ACROSS THE
PIEDMONT AS WELL AS THE HIGHER TERRAIN OF SE WV INTO NW NC THIS
MORNING WILL FADE SOON. SKIES ARE GOING TO CLEAR UP BY THIS
AFTERNOON IN THE DOWNSLOPE AREAS WHICH IS MOST OF THE FORECAST
AREA WITH OVC SKIES IN THE WV MTNS/FAR SW VA MTNS SHRINKING
THROUGH THE AFTERNOON TO PARTLY SUNNY THEN CLEAR BY LATE
AFTERNOON.

THE WIND GUSTS ARE STAYING BELOW ADVISORY LEVELS BUT UPSTREAM
SPEED MAX AT 5H OVER KY WILL BE MOVING ACROSS THROUGH MIDDAY AND
PRESSURE RISES CONTINUE ON THE ORDER OF 2-3 MB IN 3 HOURS...SO
WILL LET THE WIND ADVISORY RUN...BUT THINK AS THE MIXING HEIGHTS
RISE THROUGH THE DAY...THE GUSTS WILL TAIL OFF TO UNDER 40
MPH...SO LOOKING AT POTENTIALLY CANCELING THE WIND ADVISORY
EARLY.

TEMPERATURES WERE TRICKY GIVEN THE LAG IN THE COLDER AIR. AT 600
AM BCB WAS 57 THEN DROPPED TO AROUND 50 AT 800 AM. WILL SEE TEMPS
REBOUND SOME AS THE LATE MAY SUN RETURNS BUT WINDS AND THICKER
CLOUDS THIS MORNING WILL HINDER THIS IN THE WEST. STILL LOOKING AT
50S WEST...SOME 40S HIGHER ELEVATIONS...WITH 60S EAST...TO CLOSE
TO 70 EAST OF LYH/DAN.

PREVIOUS VALID DISCUSSION...

THE WEATHER PATTERN THROUGH THE WEEKEND...ESPECIALLY TODAY...WILL
LOOK LIKE SOMETHING WE MORE COMMONLY SEEN DURING THE WINTER AS
OPPOSED TO LATE MAY...AS A DEEP UPPER LEVEL LOW PASSES FROM THE
GREAT LAKES TOWARD LOWER NEW ENGLAND.

THIS EVENING AND TONIGHT...WIND SPEEDS WILL DIMINISH BY SUNSET AS
THE PRESSURE GRADIENT RELAXES...AND TEMPERATURES WILL DROP QUICKLY
WITH MOSTLY CLEAR SKIES EXPECTED FOR THE AREA. WILL BE LOOKING FOR
OVERNIGHT LOWS TO FALL INTO THE UPPER 30S FURTHER EAST OF THE
BLUE RIDGE...AND INTO THE LOW/MID 30S ACROSS THE MOUNTAINS. WIND
SPEEDS WILL REMAIN STRONG ENOUGH THROUGH THE NIGHT TO PREVENT
FROST IN ALL BUT THE MOST SHELTERED LOCATIONS...HOWEVER BELIEVE
THAT ENOUGH COLD AIR WILL REACH INTO BATH AND GREENBRIER COUNTIES
TO WARRANT A FREEZE WARNING...ESPECIALLY IN THE HIGHER ELEVATIONS.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...

DEEP UPPER LOW AND ASSOCIATED ANOMALOUS COLD 850MB TEMPS WILL BEGIN
TO LIFT TO THE NE SATURDAY AS UPPER FLOW REMAINS SLOWLY PROGRESSIVE
AND A BROAD UPPER RIDGE BEGINS TO SPREAD FROM THE CENTRAL U.S. INTO
THE EASTERN U.S. THE 850MB 0C ISOTHERM WILL LIFT NE TOWARD THE DC
METRO AREA BY SAT EVENING. TEMPERATURES WILL REMAIN WELL BELOW
NORMAL AGAIN SATURDAY...ALTHOUGH INCREASED SUNSHINE...ESPECIALLY
ACROSS THE MOUNTAIN AREAS...WILL HELP TEMPERATURES RECOVER SOME FROM
AN UNSEASONABLY COLD MORNING WITH LOWS OF FREEZING IN THE HIGHER
ELEVATIONS OF THE ALLEGHANYS...TO WIDESPREAD MID AND UPPER 30S
ACROSS MUCH OF THE WESTERN PART OF THE CWA...ESPECIALLY ELEVATIONS
ABOVE 2000 FT. EXPECT AFTERNOON TEMPS TO RECOVER INTO THE 60S WEST
AND LOWER 70S PIEDMONT...WITH SOME 50S DEFINITELY HANGING ON ACROSS
THE HIGHER ELEVATIONS OF BATH AND GREENBRIER COUNTIES. MOST OF THE
MEDIUM RANGE MODELS DEPICT POTENTIAL FOR HIGH CLOUDS TO SPREAD FROM
THE PLAINS SOUTHEASTWARD TOWARD OUR REGION IN INCREASINGLY STRONG
MID-LEVEL WAA. THIS WILL CONTINUE AND INCREASE INTO SUN MORNING
WHICH SHOULD LIMIT RADIATIONAL COOLING. STRONG WAA ALOFT SHOULD KEEP
HIGHER ELEVATIONS WARMER AS WELL. THUS...DO NOT SEE ANY NEED FOR
FROST/FREEZE HEADLINES SUN MORNING AT THIS TIME. TEMPERATURES WILL
CONTINUE TO RECOVER SUN AFTERNOON...BUT LIKELY REMAIN SEVERAL
DEGREES BELOW NORMAL AGAIN. NO PCPN EXPECTED THROUGH THE WEEKEND.

BY MON INTO TUE...A BROAD SUBTROPICAL RIDGE CONTINUES TO SPREAD INTO
AND AMPLIFY FROM THE MID-SOUTH INTO THE MIDWEST. WITH THE UPPER
TROUGH STILL LINGERING ACROSS THE CENTRAL-NORTH ATLANTIC...NW FLOW
ALOFT WILL PREVAIL ACROSS OUR REGION. OUR ATTENTION WILL FOCUS ON A
SERIES OF NW FLOW DISTURBANCES SLATED TO RIDE OVER THE BUILDING
RIDGE AND TOWARD THE MID-ATLANTIC REGION...ESPECIALLY IN THE LATE
MON-TUE PERIOD...BEFORE THE RIDGE AMPLIFIES ENOUGH TO SHOVE THIS
CONVEYER BELT OF DISTURBANCES FURTHER NORTH TOWARD PA/NY. THE AIR
MASS ACROSS THE REGION WILL BECOME INCREASINGLY MOIST AND
UNSTABLE...ESPECIALLY TUE...AS TEMPS RISE INTO THE 70S AND LOWER 80S
WITH DEWPOINTS RISING INTO THE 50S AND LOW 60S. WILL NEED TO WATCH
FOR NW FLOW/MCS TSRA ACTIVITY DEVELOPING ACROSS THE UPPER MIDWEST/OH
VALLEY TO RIDE SE ALONG THE MID-LEVEL BAROCLINIC ZONE. NOT EXPECTING
MUCH QPF CONCERN WITH THIS ACTIVITY AS THE SFC AIR MASS WILL BE
SLOWLY RECOVERING FROM THE ABNORMALLY LOW DEWPOINTS IN PLACE SUN-
MON...BUT STRONG THUNDERSTORM WIND GUSTS WILL BE A
CONCERN...ESPECIALLY AS THE ACTIVITY DOWNSLOPES TOWARD THE ROANOKE
VALLEY. STILL QUITE A WAYS OUT THERE...BUT THE MODELS HAVE BEEN
PRETTY CONSISTENT IN ADVERTISING THIS PATTERN...SO IT WILL NEED TO
BE WATCHED.  TEMPERATURES SHOULD RETURN TO NORMAL LEVELS BY MON-
TUE...AND LIKELY ABOVE NORMAL BEYOND THAT.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY

LOOKS LIKE WE WILL TRADE THE COOL UPPER TROUGH FOR A MAMMOTH RIDGE
THAT WILL OVERTAKE THE EASTERN CONUS BY WEDNESDAY. FOR WEDNESDAY
AND THURSDAY...WITH THE PASSAGE OF A WARM FRONT...IT WILL BE BACK
TO REALLY WARM TEMPERATURES AND HIGHER HUMIDITY WITH THE THREAT
FOR AIRMASS SHOWERS AND THUNDERSTORMS MAINLY DURING THE PEAK
HEATING HOURS.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT THURSDAY...

THE MAIN CONCERN FOR THIS TAF PERIOD WILL BE GUSTY NW WINDS AS
THE PRESSURE GRADIENT INCREASES TO AROUND 8 MB ACROSS THE FORECAST
AREA THIS MORNING IN THE WAKE OF THE STRONG COLD FRONT THAT MOVED
THROUGH THE REGION LAST NIGHT. AS SUCH...WILL BE LOOKING AT WIND
GUSTS AS HIGH AS 30-35 KTS FOR ROA AND UP TO 25-30KTS FOR
BCB/DAN/BLF. WINDS OVERALL WILL BE THE STRONGEST AT ROA GIVEN THE
PATTERN. WINDS SHOULD DECREASE QUICKLY AFTER SUNSET AS TURBULENT
MIXING ENDS AND THE PRESSURE GRADIENT BEGINS TO RELAX AS STRONG
HIGH PRESSURE BUILDS SEWD FROM THE PLAINS.

WITH A NEAR WINTERLIKE PATTERN IN PLACE THROUGH THE TAF VALID
PERIOD...EXPECT IFR-LMVFR CIGS IN THE UPSLOPE TAF SITES ACROSS SE
WV...WITH DECREASING CLOUDS EAST OF THE ALLEGHANYS AS THE
DOWNSLOPE NW WINDS TAKE EFFECT AFTER DAYBREAK. CLOUDS SHOULD SCT
OUT TO SKC AFTER MID-MORNING EAST OF THE ALLEGHNYS...WITH SLOWLY
DECREASING CLOUDS THROUGH EARLY AFTERNOON IN SE WV. ALL SITES
SHOULD BE VFR BY LATE AFTERNOON. ISOLD -RA MAY PERSIST ACROSS SE
WV THROUGH MID-MORNING.

.EXTENDED AVIATION DISCUSSION...
HIGH PRESSURE TO KEEP US VFR THROUGH THE WEEKEND. MOISTURE
INCREASES AGAIN NEXT WEEK AS THE SFC HIGH MOVES EAST AND THE UPPER
RIDGE STRENGTHENS OVER THE MISSISSIPPI VALLEY. WILL BE GETTING TO
MORE HUMID WEATHER AGAIN WITH SOME THUNDERSTORM THREAT BY TUESDAY
AND FOG ISSUES AT NIGHT IN THE VALLEYS.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL 7 PM EDT THIS EVENING FOR VAZ009-012>017-
     022.
     FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR VAZ020.
NC...WIND ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ001-002-018.
WV...FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ045.

&&

$$
SYNOPSIS...NF/WP
NEAR TERM...NF/WP
SHORT TERM...RAB
LONG TERM...PM
AVIATION...JH/NF/RAB