Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 261153
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
753 AM EDT TUE MAY 26 2015

.SYNOPSIS...
HIGH PRESSURE IS CENTERED JUST OFF THE SOUTHEAST ATLANTIC COAST.
AN UPPER LEVEL TROUGH OF LOW PRESSURE IS OVER THE CENTRAL UNITED
STATES AND WILL SLOWLY PROGRESSING EASTWARD TOWARD THE
APPALACHIANS. SOUTHERLY WIND FLOW BETWEEN THESE TWO FEATURES WAS
TRANSPORTING MOISTURE NORTHWARD FROM THE GULF OF MEXICO AND
RESULTING IN AREAS OF CLOUD COVER...SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 500 AM EDT TUESDAY...

INCREASING CLOUD COVER IS ANTICIPATED TODAY AS SOUTHERLY WINDS
TRANSPORT MOISTURE INTO THE AREA FROM THE GULF OF MEXICO.
DEWPOINTS WILL TREND UPWARD AND COMBINE WITH DAYTIME HEATING TO
YIELD SCATTERED SHOWERS AND THUNDERSTORMS.

HIGH PRESSURE WHICH PASSED OVERHEAD DURING THE HOLIDAY WEEKEND
PROVIDING THE NEAR CLOUD FREE CONDITIONS IS NOW POSITIONED JUST
OFF THE SOUTHEAST ATLANTIC COAST. LOSS OF STRONG SUBSIDENCE WILL
NOW OPEN THE DOOR FOR SHOWERS PER INCREASING MOIST SOUTHERLY FLOW
ON THE WESTERN PERIPHERY OF THE ANTICYCLONE. DEWPOINTS CLIMBING
INTO THE 60S ALONG WITH DAYTIME HEATING WILL RESULT IN INCREASING
INSTABILITY AND THE FORMATION OF SCATTERED SHOWERS AND
THUNDERSTORMS. SHOWER ACTIVITY TODAY IS EXPECTED TO BE MOST
PRONOUNCED OVER THE MOUNTAINS...PRIMARILY ALONG AND WEST OF THE
BLUE RIDGE.

AN UPPER LEVEL TROUGH OF LOW PRESSURE OVER THE MID SECTION OF THE
COUNTRY IS SLOWLY MOVING EAST WITH NUMEROUS SHOWERS/STORMS.
OUTFLOW FROM SOME OF THIS ACTIVITY WILL LIKELY REACH OUR WESTERN
MOUNTAINS TONIGHT ALLOWING FOR A CONTINUED THREAT FOR DEEP
CONVECTION DURING THE OVERNIGHT.

TEMPERATURES TODAY WILL BE SIMILAR TO MONDAY...MAYBE EVEN A DEGREE
OR TWO LOWER IN THE MOUNTAINS PER INCREASING CLOUD COVER.
DEWPOINTS HOWEVER...WILL BE ON THE INCREASE...AND OFFSET ANY
PERCEIVED COOLING...THE HIGHER HUMIDITY RESULTING IN HIGHER
APPARENT TEMPERATURES WITH THE AIR HAVING MORE OF A MUGGY FEEL.
MINIMUM TEMPERATURES TONIGHT WILL LIKELY REMAIN AOA 60...HIGHER
DEWPOINTS AND CLOUD COVER LIMITING THE RADIATIVE COOLING EFFECTS.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 500 AM EDT TUESDAY...

EXPECT SCATTERED SHOWERS AND THUNDERSTORMS FOR MUCH OF THE AREA ON
WEDNESDAY AS AN UPPER LEVEL TROUGH PASSES ACROSS THE APPALACHIAN
CHAIN. THE TROUGH IS EXPECTED TO BE CLOSE ENOUGH TO OUR WESTERN
BORDER SUCH THAT SHOWER ACTIVITY WILL BE ONGOING AT THE START OF THE
DAY ACROSS THE MOUNTAINS. BEST DYNAMICS/STRONGEST INSTABILITY
ASSOCIATED WITH THE TROUGH WILL REMAIN NORTH OF THE AREA. IN
ADDITION...RAINFALL AND WIDESPREAD CLOUD COVER EARLY IN THE DAY WILL
LIMIT HEATING AND SURFACE-BASED INSTABILITY...AND DO NOT EXPECT
ORGANIZED SEVERE THUNDERSTORM ACTIVITY...ALTHOUGH A FEW STRONG
STORMS WILL STILL BE POSSIBLE DURING THE AFTERNOON AND EVENING. ON
THE OTHER HAND...WITH DEEP GULF MOISTURE IN PLACE...WILL HAVE TO
KEEP AN EYE OUT FOR LOCALLY HEAVY RAIN...AS WELL AS THE POSSIBILITY
OF ISOLATED/MINOR FLOODING ISSUES.

UPPER LEVEL RIDGING WILL REDEVELOP ON THURSDAY ACROSS THE SOUTHEAST/
MID ATLANTIC STATES. WHILE WEAK UPPER LEVEL DISTURBANCES WILL STILL
PASS ACROSS THE AREA...SHOWER AND THUNDERSTORM ACTIVITY FOR THURSDAY
AND FRIDAY WILL BE DRIVEN MORE BY DAYTIME HEATING OF THE SOUPY AIR.
CONVECTION WILL INCREASE LATE EACH MORNING...PEAK DURING EARLY
EVENING...AND WILL DIMINISH AFTER SUNSET...ALTHOUGH DO NOT THINK
RAINFALL WILL GO AWAY COMPLETELY EACH NIGHT AS SPOTTY SHOWERS LINGER
ACROSS THE AREA. WITH LITTLE UPPER LEVEL SUPPORT...EXPECT ONLY
LOCALLY STRONG THUNDERSTORMS EACH DAY WITH NO ORGANIZED ACTIVITY.
UPPER LEVEL RIDGING WILL MAKE FOR LIGHT WINDS ALOFT AND SLOW STORM
MOVEMENT...SO THE THREAT OF LOCALLY HEAVY RAIN WILL CONTINUE THROUGH
THE END OF THE WORKWEEK.

INCREASED CLOUD COVER DURING THE PERIOD WILL LIMIT HEATING...HOLDING
AFTERNOON HIGHS IN THE MID TO UPPER 70S ACROSS THE MOUNTAINS...AND
THE LOW/MID 80S EAST OF THE BLUE RIDGE. WITH NO CHANGE IN AIRMASS
EXPECTED...EXPECT MUGGY CONDITIONS EACH NIGHT...WITH LOWS HOLDING IN
THE LOW/MID 60S AREAWIDE.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...

IN EXTENDED PERIOD THE SYNOPTIC SETUP DOES NOT REALLY CHANGE TOO
MUCH. THE RIDGE OVER THE ATLANTIC COAST CONTINUES TO DIRECT A STEADY
SUPPLY OF WARMTH AND MOISTURE INTO THE EASTERN SEABOARD. AT THE SAME
THERE WILL BE A CHANCE FOR SOMEWHAT MORE ORGANIZED ACTIVITY
ASSOCIATED WITH A SLOW-MOVING BOUNDARY TRAILING FROM A SURFACE LOW
TRACKING INTO THE GREAT LAKES ON SATURDAY. THE ECMWF SHOWS THIS
FEATURE BECOMING QUASI-STATIONARY TO OUR NORTH OH-PA-NJ AXIS ON LATE
SATURDAY INTO MONDAY AND THEN POSSIBLY SLIDING FARTHER SOUTH INTO
OUR AREA BY LATER MONDAY. GFS PERHAPS A BIT FURTHER NORTH WITH THIS
FEATURE AND MORE PROGRESSIVE AND EVENTUALLY BUILDS HIGH PRESSURE
OVER THE NORTHEAST WHICH PUSHES A BACKDOOR TYPE FRONT TOWARD THE
AREA LATE SUNDAY. GFS ENSEMBLES SOLUTION THROUGH THIS PERIOD MOSTLY
MAINTAIN THE RIDGE OVER THE SOUTHEAST IN A POSITION THAT WOULD HOLD
THE BOUNDARY AND ASSOCIATED PRECIPITATION FURTHER NORTH. HPC
GUIDANCE CLOSER TO EURO SOLUTION AND WAS BASICALLY FOLLOWED FOR THE
EXTENDED. THIS ALL MEANS CONTINUED WELL ABOVE NORMAL
TEMPERATURES...ESPECIALLY AT NIGHT...ALONG WITH ABUNDANT MOISTURE
AND HIGH CHANCES FOR AT LEAST AFTERNOON/EVENING CONVECTION.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 800 AM EDT TUESDAY...

SFC HIGH IS CENTERED JUST OFF THE MID-ATLANTIC COAST AND IS NOW IN
A POSITION TO ALLOW WARM/MOIST GULF AIR TO SPREAD INTO THE REGION
FROM THE SOUTHWEST. THIS WILL RESULT IN INCREASING CLOUDINESS WITH
POTENTIAL FOR MVFR CIGS DEVELOPING ACROSS MUCH OF THE AREA THIS
MORNING. WITH DAYTIME HEATING...THESE CLOUDS WILL GRADUALLY LIFT
INTO LOW END VFR RANGE BY LATE MORNING/EARLY AFTERNOON. THE CLOUDS
WILL LIKELY PREVENT MUCH IN THE WAY OF FOG DEVELOPMENT...BUT
CANNOT TOTALLY IGNORE THE HIGHER DEWPOINTS AND THE POTENTIAL FOR
LIGHT FOG AROUND DAYBREAK THIS MORNING.

WITH INCREASING MOISTURE COMES THE POTENTIAL FOR DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORMS...FAVORING THE MOUNTAINS TODAY...THEN
AREAWIDE WEDNESDAY AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE
REGION.

WINDS TODAY WILL BE OUT OF THE SOUTH 5-10KTS...WITH GUSTS
14-18KTS.

EXTENDED AVIATION DISCUSSION...

WEDNESDAY...A SIGNIFICANT UPPER DISTURBANCE...NOW ACROSS OK/TX AND
GENERATING WIDESPREAD SEVERE WEATHER AND FLOODING IN THAT
REGION...WILL REACH OUR REGION. THIS ALONG WITH A WEAK
BOUNDARY...EVIDENT IN SEVERAL OF THE MODELS...SHOULD ENHANCE
SHRA/TSRA ACTIVITY ACROSS THE REGION...ESPECIALLY WED AFTERNOON.
THIS BOUNDARY DRIFTS INTO EASTERN VA THU BEFORE WASHING OUT...SO
ACTIVITY COULD BE SOMEWHAT MORE FOCUSED ALONG-EAST OF THE BLUE
RIDGE THURSDAY.

FOR THE REMAINDER OF THE PERIOD...A MOIST UNSTABLE AIR MASS
REMAINS ACROSS THE REGION WITH WEAK TRIGGERING MECHANISMS AND
DYNAMICS. A FRONTAL SYSTEM WILL APPROACH FROM THE NORTH BY THE
WEEKEND...BUT WILL LIKELY REMAIN WELL NORTH OF THE CWA. THUS...NO
CHANGE IN AIR MASS OR THE OVERALL SYNOPTIC PATTERN IS EXPECTED
THROUGH THE PERIOD.

EARLY MORNING LOW CLOUDS/FOG AND ASSOCIATED IFR-LIFR CIGS/VSBYS BECOME
INCREASINGLY MORE LIKELY THROUGH THE PERIOD...ESPECIALLY FOLLOWING
ANY LATE DAY RAINFALL. OTHERWISE...EXPECT MOSTLY VFR-MVFR CIGS
OUTSIDE HEAVIER SHOWERS/THUNDERSTORMS. WINDS REMAINING SW 5-10KTS
THROUGH MUCH OF THE PERIOD...EXCEPT VARIABLE AND GUSTY IN/NEAR
THUNDERSTORMS.

&&

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

&&

$$
SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...NF
LONG TERM...NF/PC
AVIATION...PM



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