Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 180245
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1045 PM EDT WED SEP 17 2014

.SYNOPSIS...
A COOL WEDGE OF HIGH PRESSURE TO OUR NORTH WEAKENS OVERNIGHT INTO
THURSDAY. ANOTHER LARGER AREA OF HIGH PRESSURE WILL STRENGTHEN TO
THE NORTH OF THE US FRIDAY INTO SATURDAY BEFORE PASSING OFFSHORE
ON SUNDAY. A COLD FRONT WILL CROSS THE AREA FROM THE NORTHWEST ON
MONDAY BRINGING A BETTER CHANCE OF SHOWERS TO START THE WEEK.

&&

.NEAR TERM /THROUGH THURSDAY/...
AS OF 1045 PM EDT WEDNESDAY...

SKIES EXPECTED TO CLOUD BACK OVER DURING THE OVERNIGHT. OVERCAST
CONDITIONS CURRENTLY EXIST OVER THE FAR WESTERN CWA FROM BLUEFIELD
WV TO BOONE NC. THIS AREA OF CLOUD COVER IS EXPECTED TO SPREAD
OUT OVERNIGHT AS MOISTURE POOLS UNDERNEATH THE SUBSIDENCE
INVERSION VIA THE SHALLOW EASTERLY FLOW. THE EVENING RNK SOUNDING
SHOWED INVERSION LAYER BETWEEN 4-7KFT AGL.

AMPLITUDE OF UPPER TROUGH DOES NOT CHANGE TOO MUCH HEADING INTO
THURSDAY. THINK WE WILL SEE CLOUD COVER EXPAND AGAIN LATER TONIGHT
ONCE THE INVERSION SETS UP TRAPPING THE LOW LVL MOISTURE. THERE
IS STILL SOME VARIABILITY IN THE CLOUD COVER FORECAST PER MODEL
WITH THE NAM HAVING MORE CLOUDS WITH LESS ON THE CMC. GFSMOSGUIDE
SEEMS TO BE A TWEENER SO LEANED TOWARD ITS SOLUTION WITH
MODIFICATIONS. WITH CLOUDS AROUND THINK THE TEMPS WILL BE AFFECTED
SOME...SO LEANED TOWARD MET GUIDANCE NUMBERS OF LOWER 50S
MOUNTAINS TO UPPER 50S SOUTHEAST.

THE CLUSTER OF SHOWERS AND STORMS ACROSS NRN ARKANSAS/SOUTHERN
MISSOURI WILL STAY WELL TO OUR SOUTH. WILL SEE A PIECE OF SHORTWAVE
ENERGY MOVE BY THURSDAY WITH SOME CONVERGENCE ALONG THE BLUE RIDGE
TO SQUEEZE OUT A FEW SHOWERS. NOT THINKING MORE THAN 20ISH POPS
ALONG AND EITHER SIDE OF THE BLUE RIDGE. SKY COVER WILL AGAIN START
OUT CLOUDY IN THE MORNING THEN TRANSITION TO PARTLY SUNNY-MOSTLY
CLOUDY IN THE AFTERNOON WITH MORE SUNSHINE PUSHING INTO THE
MOUNTAINS ONCE THE UPPER WAVE PASSES. JUST A SLIGHT INCREASE IN
HEIGHTS WILL LEAD TO HIGHS IN THE UPPER 60S/LOWER 70S MOUNTAINS...TO
UPPER 70S OUT ACROSS THE PIEDMONT.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM EDT WEDNESDAY...

SHORT WAVE TOPPING WESTERN UPPER RIDGE TRACKS INTO THE SOUTHEAST
UNITED STATES...POTENTIAL CLOSING OFF BY LATE FRIDAY.

PARTICULARLY STRONG WEDGE BUILDS INTO THE AREA BY FRIDAY MORNING.
BUFKIT SOUNDINGS SHOW A SURFACE BASED SATURATED LAYER AS MUCH AS
5000 FEET DEEP TOPPED BY MUCH DRY AIR AND WITH EAST TO SOUTHEAST
WINDS FROM LATE THURSDAY NIGHT THROUGH MID AFTERNOON ON FRIDAY.
EXPECT WIDESPREAD CLOUDS IN THE WEDGE AND AREAS OF DRIZZLE AND FOG
IN THE FAVORED EASTERN UPSLOPE AREAS. STAYED AT OR BELOW COOLER MAV
GUIDANCE IN THE WEDGE ON FRIDAY. NEAR THE FRINGES OF THE LOW
CLOUDS...IN THE FAR WESTERN COUNTY WARNING AREA...MORE SUNSHINE WILL
RESULT IN WARMER TEMPERATURES.

SIMILAR PATTERN AGAIN FOR FRIDAY NIGHT...BUT ON SATURDAY FLOW
BECOMES SOUTHWEST. EXPECT ENOUGH SUNSHINE BY AFTERNOON FOR WARMER
TEMPERATURES ACROSS THE ENTIRE FORECAST AREA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 300 PM EDT WEDNESDAY...

UPPER TROF DIGS OVER THE EASTERN UNITED STATES THROUGH MONDAY NIGHT
WITH THE TROF AXIS CROSSING THE COUNTY WARNING AREA ON TUESDAY.
MODELS OFFER DIFFERENT SOLUTIONS AFTER TUESDAY. LEANING TOWARD THE
ECMWF ENSEMBLE WHICH HAS A BRIEF PERIOD OF NORTHWEST FLOW THEN RISING
HEIGHTS ON WEDNESDAY.

SURFACE LOW PRESSURE OFF THE SOUTH CAROLINA COAST MOVES NORTHEAST
AND WILL BE OFF THE VIRGINIA COAST BY LATE SUNDAY. AT THE SAME
TIME...HIGH PRESSURE AND THE WEDGE WEAKENS AS A COLD FRONT
APPROACHES FROM THE OHIO VALLEY. MODELS HAVE BEEN CONSISTENT OVER
THE PAST FEW RUNS...BRINGING THE COLD FRONT THROUGH THE FORECAST
AREA ON MONDAY.

A VERY LARGE NEARLY 1030MB HIGH WILL COVER MUCH OF THE UNITED STATES
EAST OF THE MISSISSIPPI RIVER TUESDAY AND WEDNESDAY. MONDAY NIGHT
AND TUESDAY NIGHT BEHIND THE FRONT...ECMWF HAS 850 MB TEMPERATURES
OF +6 TO +8. THIS WILL YIELD TEMPERATURES VERY CLOSE TO NORMAL FOR
THE FIRST FEW NIGHTS OF FALL.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AS OF 730 PM EDT WEDNESDAY...

SKIES HAVE TEMPORARILY CLEARED. THINK VFR WILL PREVAIL THROUGH THE
EVENING...THEN DETERIORATE AFTER MIDNIGHT. ONCE THE SURFACE BASED
INVERSION SETS UP LOOK FOR PATCHY DENSE FOG...ESP IN THE MOUNTAIN
VALLEYS. CLOUD LAYER ALSO EXPECTED TO FORM UNDERNEATH THE
SUBSIDENCE INVERSION WITH CLOUD LAYER DEVELOPING BETWEEN
020-030KFT. AFTER 14Z...CONDITIONS WILL IMPROVE BACK INTO THE VFR
CATEGORY...ANY LOW CIGS LIFTING INTO THE 040-060KFT RANGE FOR
THURSDAY AFTERNOON.

EXTENDED AVIATION DISCUSSION...

HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH THE END OF THE
WEEK WITH LITTLE OR NO PRECIPITATION. EXPECT MAINLY VFR
CONDITIONS OUTSIDE ANY FOG AT NIGHT AND POTENTIAL FOR SOME LOW
LEVEL STRATUS ALONG AND EAST OF ROA/BCB...THOUGH THE HIGH
PRESSURE SHOULD BE STRONG ENOUGH TO KEEP MOISTURE LIMITED.
PRESENCE OF SUBSIDENCE INVERSION ALOFT WILL LIKELY RESULT IN
CLOUD LAYER PERSISTING BETWEEN 040-060KFT...SO IT WILL NOT BE
ENTIRELY CLEAR.

NEXT UPSTREAM TROUGH AND FRONT EXPECTED TO ARRIVE BY EARLY NEXT
WEEK WITH A THREAT OF SHOWERS. MAY SEE SOME MVFR CIGS/VSBYS BUT
APPEARS MOST OF THE TIME WILL CONTINUE TO SEE VFR.

&&

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

&&

$$
SYNOPSIS...WP
NEAR TERM...PM/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...PM


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