Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 191651
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1251 PM EDT SAT APR 19 2014

.SYNOPSIS...
A DEEP AREA OF LOW PRESSURE ALOFT ACROSS THE SOUTHEAST STATES WILL
MOVE VERY SLOWLY EASTWARD THROUGH THE WEEKEND...MOVING OFF THE
COAST BY MONDAY...KEEPING CLOUDS AND LIGHT RAIN ACROSS SOUTHERN
SECTIONS TODAY INTO EARLY SUNDAY. HIGH PRESSURE WILL BUILD ACROSS
THE REGION FOR LATER SUNDAY INTO MONDAY. BY TUESDAY...A COLD FRONT
AND ASSOCIATED UPPER TROUGH WILL MOVE INTO THE REGION FROM THE
NORTHWEST BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS...FOLLOWED
BY BREEZY AND COOLER CONDITIONS FOR THE MID PART OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1155 AM EDT SATURDAY...

UPDATED TO RAISE HIGH TEMPS ANOTHER CAT OR TWO ESPCLY NORTH/EAST
GIVEN MORE BREAKS AND THINNING OF CLDNS ONGOING NORTH OF THE
PERSISTENT RAINBAND ACROSS NW NC. THIS WILL RESULT IN A GRADIENT
BETWEEN MID/UPPER 60S NORTH TO PERHAPS ONLY AROUND 50 FAR SW WHERE
CLOUDS/PRECIP WILL CONTINUE. ALSO LOWERED POPS IN SOUTHERN VA TO
REFLECT DECREASE IN COVERAGE DURING THE PAST HOUR OR TWO WHILE
MAINTAINING CAT POPS WATAUGA/WIKLES AND YADKIN CTYS.

AS OF 930 AM EDT SATURDAY...

ELONGATED BAND OF RAIN ASSOCIATED WITH THE MID LEVEL DEFORMATION
ZONE OF THE BROAD UPPER LOW ACROSS NORTH FLORIDA REMAINS ACROSS
THE FAR SOUTHERN TIER THIS MORNING. HOWEVER LATEST MORNING
SOUNDINGS CONTINUE TO SHOW A STRONG NE FLUX OF DRIER AIR IN THE
LOWER LEVELS AS EVIDENCED VIA THE RNK RAOB. THIS HAS CAUSED SOME
DRYING TO TAKE PLACE ALONG THE BLUE RIDGE SOUTH TO NEAR THE
VIRGINIA BORDER WHICH IS CLOSER TO THE LATEST HRRR SOLN THAT
ATTEMPTS TO SHIFT ALL THE PRECIP SOUTH THIS AFTERNOON. GFS
CONTINUES TO MAINTAIN THE AXIS OF LIGHT RAIN WITH MORE EASTERLY
INFLOW OFF THE ATLANTIC AS THE UPPER SYSTEM ONLY DRIFTS TO OFF THE
SE COAST BY THIS EVENING. THIS SCENARIO APPEARS MORE IN LINE WITH
A SHARP GRADIENT FROM SOME SUN NORTH...TO CLOUDS CENTRAL
SECTIONS...WITH CONTINUED PERIODS OF -RA VA/NC BORDER AND POINTS
SOUTH AS THE BAND TENDS TO STRETCH OUT WHILE SLOWLY DIMINISHING
THROUGH THE AFTERNOON. THIS SUPPORTS KEEPING CAT/LIKELY POPS A
WHILE LONGER ACROSS MUCH OF NW NC INTO SOUTHSIDE VIRGINIA WITH A
QUICK DROPOFF TO DRY CONDITIONS FROM JUST SOUTH OF HIWAY 460 AND
POINTS NORTH.

HIGH TEMPS REMAIN TRICKY WITH POTENTIAL FOR HIGHS TO STRUGGLE TO
TOP 50 UNDER THE RAIN WHILE REACHING THE LOW/MID 60S FAR
NORTH/WEST WITH 56-63 BCB-ROA-LYH CORRIDOR PENDING DEGREE OF ANY
BREAKS. THUS INCREASED THE GRADIENT THIS AFTERNOON SINCE ALREADY
ABOVE HIGHS IN SPOTS NORTH OF THE MAIN RAIN/CLOUD SHIELD ATTM.

PREVIOUS DISCUSSION...

MAIN CONCERN THROUGH THE NEAR TERM CONTINUES TO BE SLOW
MOVING...INCREASINGLY VERTICALLY STACKED UPPER LOW ACROSS THE
SOUTHEAST STATES. FINALLY...AFTER SEVERAL DAYS OF DIFFERING
SOLUTIONS AMONG THE MODELS...THE GFS/ECMWF/NAM/CANADIAN HAVE ALL
CONVERGED ON A SIMILAR SOLUTION. EXPECT -RA TO GENERALLY REMAIN IN
AN AREA THROUGH THIS EVENING SIMILAR TO WHERE IT IS...NAMELY
MOSTLY ALONG AND EAST OF THE BLUE RIDGE FROM TNB-HLX-LYH. WITH THE
UPPER LOW MOVING ALMOST DUE EAST THROUGH THE PERIOD...SEE LITTLE
NORTHWARD PROGRESS OF THE RAIN FROM THESE POINTS...BUT BY THE SAME
TOKEN...LITTLE SOUTHWARD PROGRESS UNTIL THE UPPER LOW MOVES CLOSER
TO THE COAST...ALLOWING DRIER NE FLOW TO ADVECT SOUTHWARD INTO THE
REGION. FOR AREAS FURTHER NORTH AND WEST...CONSIDERABLE HIGH
CLOUDS WILL PERSIST AND EVEN SOME MID CLOUDS ARE EXPECTED TO REACH
THE ALLEGHANY FRONT...BUT LITTLE TO NO PRECIPITATION WEST OF THE
BLUE RIDGE. GFS/ECMWF BOTH CLEARLY DEPICT A SMALL DEFORMATION ZONE
TO DEVELOP ACROSS NORTHWEST NC THIS EVENING...PROLONGING THE
PRECIPITATION IN THAT AREA. HAVE INCREASED POPS TO LIKELY AND
CATEGORICAL AND EXTENDED LONGER INTO OUR SOUTHERN TIER OF COUNTIES
THAN EARLIER ADVERTISED.

SYNOPTIC PATTERN AND -RA...SOME WHAT OF AN INSITU WEDGE REINFORCED
WITH  NE FLOW AROUND SE U.S. DEVELOPING SFC LOW PRESSURE...WILL
KEEP THE PIEDMONT THE COOLEST TODAY. HAVE LEANED TOWARD THE ECMWF
MOS...WHICH WAS THE COOLEST AMONG THE MAV/MET/ECS. HOWEVER...EVEN
UNDERCUT IT BY ABOUT ONE CATEGORY IN THE RAINY PIEDMONT AREAS. THE
MOUNTAINS OF NORTHWEST NC WILL STRUGGLE TO REACH 50. THE WARMEST
AREAS TODAY SHOULD BE WEST OF THE ALLEGHANY FRONT...LWB-BLF-
MKJ...WHERE LOW 60S ARE POSSIBLE IF THE CLOUDS THIN OUT ENOUGH
DURING THE MID AND LATE AFTERNOON.

WINDS WILL REMAIN NE EAST OF THE ALLEGHANY FRONT AND GENERALLY
E-SE TO THE WEST. SPEEDS WILL INCREASE DURING THE AFTERNOON AND
EVENING AS A TIGHT PRESSURE GRADIENT DEVELOPS BETWEEN THE LOW
PRESSURE ACROSS SC AND HIGH PRESSURE RIDGING SOUTHWARD FROM NEW
ENGLAND.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 400 AM EDT SATURDAY...

FOR EASTER SUNDAY...MAY SEE A FEW RESIDUAL SPRINKLES ACROSS THE
SOUTHSIDE AND THE NORTH CAROLINA PIEDMONT TO START THE DAY...HOWEVER
THESE WILL QUICKLY EXIT THE AREA AS LOW PRESSURE EXITS OFF THE
SOUTHEAST COAST. OTHERWISE...EXPECT CLEARING SKIES AS HIGH PRESSURE
REMAINS WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS...
RESULTING IN A LIGHT AND GENERALLY EASTERLY WIND FLOW. WITH THE COOL
HIGH PRESSURE WEDGE IN PLACE...WENT A LITTLE BELOW MODEL GUIDANCE
FOR AFTERNOON TEMPERATURES...WITH HIGHS CLIMBING INTO THE MID AND
UPPER 60S MOST LOCATIONS OUTSIDE OF THE HIGHER RIDGES. LIGHT WINDS
AND MOSTLY CLEAR SKIES WILL ALLOW FOR STRONG RADIATIONAL COOLING
SUNDAY NIGHT...WITH LOWS BOTTOMING OUT IN THE UPPER 30S AND LOW
40S...WITH A FEW MOUNTAIN VALLEYS DROPPING BELOW FREEZING.

UPPER LEVEL RIDGING BECOMES MORE FIRMLY ESTABLISHED FOR MONDAY AS
THE SURFACE HIGH PRESSURE WEDGE SHOWS SIGNS OF BREAKING DOWN.
EXPECT WARMER TEMPERATURES DESPITE INCREASING MID AND HIGH
CLOUDS...WITH HIGHS REACHING INTO THE UPPER 60S AND LOW 70S. WINDS
WILL BECOME INCREASINGLY SOUTHWESTERLY THROUGH THE DAY AHEAD OF AN
APPROACHING COLD FRONT...AND THE WARMER AIR POOLING IN FROM THE
GULF COAST REGION WILL MAKE FOR MILD MONDAY NIGHT LOWS...GENERALLY
IN THE UPPER 40S AND LOW 50S.

SHOWER ACTIVITY WILL ENTER FROM THE WEST AFTER SUNRISE TUESDAY AS
THE COLD FRONT ADVANCES EAST ACROSS KENTUCKY/TENNESSEE. GFS/ECMWF/
CANADIAN FORECAST MODELS ALL INDICATE DECENT INSTABILITY DEVELOPING
DURING THE AFTERNOON ALONG AND EAST OF THE BLUE RIDGE AS A LEE SIDE
TROUGH SETS UP...WHILE STRONG HEATING WILL ALLOW TEMPERATURES TO
CLIMB INTO THE MID AND UPPER 70S. AS SUCH...CONDITIONS APPEAR
FAVORABLE FOR SCATTERED THUNDERSTORMS TO DEVELOP...A FEW OF WHICH
WILL LIKELY BECOME STRONG TO SEVERE. AT THIS POINT...BOTH HAIL AND
GUSTY WINDS WOULD BE CONCERNS. THE COLD FRONT WILL PASS ACROSS THE
AREA DURING THE EVENING...EXITING TO THE EAST AFTER MIDNIGHT
WEDNESDAY. A FEW UPSLOPE RAIN SHOWERS MAY LINGER ACROSS THE WESTERN
RIDGES THROUGH THE NIGHT...OTHERWISE CLEARING CONDITIONS ARE
EXPECTED.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 400 AM EDT FRIDAY...

BELIEVE THERE WILL STILL BE A CHANCE FOR SOME UPSLOPE RAIN SHOWERS
IN CAA WEST OF THE BLUE RIDGE EARLY WEDNESDAY...IN ADDITION TO
BREEZY CONDITIONS AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.
EXPECT QUIET WEATHER FOR THURSDAY AS HIGH PRESSURE PASSES OVERHEAD.
SHOWERS AND POSSIBLE THUNDERSTORMS WILL MOVE IN ON FRIDAY AS ANOTHER
COLD FRONT APPROACHES.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1230 PM EDT SATURDAY...

DRIER LOW LEVEL NE FLOW HAS CONTINUED TO MAINTAIN VFR STATUS AT
ALL TAF SITES ATTM WITH MOSTLY A MID TO HIGH BKN/OVC CANOPY IN
PLACE. EXPECT THIS OVERALL TREND TO PREVAIL THIS AFTERNOON WITH
MOST OF THE MVFR CONDITIONS STAYING ALONG THE SRN BLUE RIDGE IN NW
NORTH CAROLINA AND JUST SOUTH OF DAN. MAY SEE SOME LOW END VFR
CIGS DEVELOP NORTH INTO DAN BEFORE THIS EVENING AS MOISTURE/PRECIP
STARTS TO JOG BACK NORTH AHEAD OF ANOTHER WAVE SET TO MOVE ACROSS
OVERNIGHT. COULD ALSO BE SOME SPOTTY -RA ACROSS THE DAN VICINITY
AS WELL BUT OVERALL VFR WITH DRY WEATHER ELSW THIS AFTERNOON.

LOW CONFIDENCE FORECAST OVERNIGHT WITH SOME GUIDANCE SUGGESTING
THE NEXT MID LEVEL WAVE MAY BRING PRECIP BACK NORTH AT LEAST INTO
DAN THIS EVENING BEFORE EXITING EARLY SUNDAY. THIS WOULD ALSO
BRING A PERIOD OF MVFR CIGS ALONG WITH VFR CIGS NORTH TO ROA/LYH
OVERNIGHT. SINCE THIS COULD BE OVERDONE GIVEN CURRENT DRY
ADVECTION AND LACK OF MODEL CONSENSUS...WILL KEEP DAN HIGH END
MVFR CIGS WITH VFR VSBYS IN -RA LATER TONIGHT...AND MAINLY SCTD
LOW CLOUDS WITH HIGHER MID DECK CIGS ELSW FROM BCB-ROA-LYH FOR
NOW.

NE WINDS WILL REMAIN GUSTY ESPCLY OVER EASTERN SECTIONS WITH THE
PRESSURE GRADIENT IN PLACE BRINGING GUSTS TO 20-25 KTS AT TIMES
INTO TONIGHT.

EXTENDED AVIATION DISCUSSION...
THE UPPER LOW SLOWLY EXITS TO THE EAST SUNDAY AND HIGH PRESSURE
RETURNS BRINGING A RETURN TO VFR CONDITIONS INTO EARLY NEXT WEEK.
MAY STILL HAVE SOME MID DECK CIGS ACROSS THE EAST SUNDAY MORNING
BEFORE SLOW CLEARING TAKES PLACE FROM WEST TO EAST BY AFTERNOON. THE
NEXT COLD FRONT APPROACHES MONDAY NIGHT WITH MORE SHOWERS AND
POSSIBLE THUNDERSTORMS INCLUDING PERIODS OF MVFR FOR TUESDAY.
FRONT EXITS TUESDAY NIGHT RESULTING IN A RETURN TO VFR WEDNESDAY
EXCEPT FOR MVFR CIGS OVER THE FAR WESTERN SITES IN SE WEST VA.
HIGH PRESSURE BUILDS IN FOR THURSDAY WITH WIDESPREAD VFR LIKELY.
&&

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

&&

$$
SYNOPSIS...RAB
NEAR TERM...JH/RAB
SHORT TERM...NF
LONG TERM...MBS/NF
AVIATION...JH/RAB/RCS



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