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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
352 PM EDT MON JUL 28 2014

.SYNOPSIS...
AN UPPER TROUGH OF LOW PRESSURE WILL REMAIN CENTERED OVER THE EAST
COAST THROUGH THE MIDDLE OF THE WEEK. LIKEWISE...COOL HIGH
PRESSURE WILL SETTLE OVER THE REGION THROUGH WEDNESDAY. DURING THE
LATTER HALF OF THE WEEK AND HEADING INTO THE WEEKEND...THE UPPER
TROUGH WILL RETROGRADE WESTWARD...AND ALLOW FOR AN INCREASE IN
MOISTURE...MODERATING TEMPERATURES...AND POTENTIAL FOR SHOWERS
AND STORMS.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 240 PM EDT MONDAY...

A COLD FRONT WAS LOCATED JUST EAST OF THE FORECAST AREA. GUSTY 
NORTHWEST WINDS WERE ADVECTING DRIER AIR INTO THE REGION. ENOUGH 
INSTABILITY AND LINGERING LOW LEVEL MOISTURE EXISTS BEHIND THE FRONT 
FOR A GENEROUS CUMULUS CLOUD STREETS ACROSS MOST OF THE AREA...WITH 
THE GREATEST ABUNDANCE IN THE WEST. ALSO...ISOLATED SHOWERS WERE 
NOTED OVER PARTS OF SOUTHEAST WEST VIRGINIA AND NEIGHBORING COUNTIES 
OF SOUTHWEST VIRGINIA. MODEL GUIDANCE SHOWS THAT THE STRONGEST 850 
MB JET STREAK CROSSED THE AREA AROUND MID-DAY...AND A TREND TOWARD 
WEAKER WINDS ALOFT WILL CONTINUE INTO THE OVERNIGHT HOURS. SURFACE 
WINDS SHOULD LIKEWISE GRADUALLY WEAKEN THIS AFTERNOON AND BECOME 
LIGHT DURING THE OVERNIGHT. LOW TEMPERATURES TONIGHT WILL BE ON THE 
COOL SIDE FOR THIS TIME OF THE YEAR...WITH MOST AREAS FORECAST 
WITHIN FIVE DEGREES OF RECORD LOW MINIMUMS. THE FORECAST LOW OF 55 
AT BLUEFIELD WOULD TIE THE RECORD. SPECIFIC RECORDS ARE IN THE 
CLIMATE SECTION OF THIS DISCUSSION.

ON TUESDAY...OUR COOL PATTERN WILL CONTINUE WITH THE AXIS OF THE 
UPPER TROUGH STILL OVER OUR REGION...AND THE CENTER OF SURFACE HIGH 
PRESSURE WILL APPROACH FROM THE WEST. EMBEDDED WITH THE MAIN UPPER 
TROUGH PATTERN...MODEL GUIDANCE OFFER A SOLUTION WITH A WEAK 
DISTURBANCE WITHIN THE MAIN FLOW CROSSING MAINLY THE SOUTHERN HALF 
OF THE AREA ON TUESDAY. WILL CONTINUE TO ALLOW FOR ISOLATED SHOWERS 
IN THE FORECAST ACROSS THE SOUTHWESTERN PART OF THE AREA...IN THE 
PATH OF THE DISTURBANCE AND WITHIN A ZONE OF WEAK UPSLOPE 850 MB 
FLOW. HIGH ON TUESDAY ARE EXPECTED TO AVERAGE AROUND FIVE DEGREES 
COOLER THAN THOSE REALIZED TODAY. LOW TO MID 70S ARE FORECAST ACROSS 
THE MOUNTAINS WITH UPPER 70S TO NEAR 80 ACROSS THE PIEDMONT.


&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 345 PM EDT MONDAY...

BY WEDNESDAY MORNING SURFACE HIGH PRESSURE IS CENTERED OVER THE 
FORECAST AREA. A VERY WEAK PRESSURE GRADIENT REMAINS IN PLACE 
THROUGH THURSDAY. PRECIPITABLE WATER VALUES GRADUALLY INCREASE BACK 
UP INTO THE 1.0 TO 1.5 INCH RANGE BY LATE THURSDAY. 

BUFKIT FORECAST SOUNDINGS FOR WEDNESDAY SHOW ENOUGH MIXING TO BRING 
DEW POINTS DOWN INTO THE 40S FOR MUCH OF THE AREA DURING THE 
AFTERNOON. WILL STAY CLOSE TO COOLER GUIDANCE FOR LOWS ON BOTH 
TUESDAY NIGHT AND WEDNESDAY NIGHT. RECORD LOWS ARE STILL POSSIBLE 
TUESDAY NIGHT WITH LOWS 5 TO 15 DEGREES BELOW NORMAL. 

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 345 PM EDT MONDAY...

UPPER 500 MB TROF OVER THE NORTHEAST UNITED STATES AMPLIFIES ON 
FRIDAY AND SATURDAY WITH A SIGNIFICANT SHORT WAVE OVER THE OHIO 
VALLEY. MODELS SIMILAR IN SHOWING HEIGHT FALLS ON THE SOUTHERN END 
OF THE TROF AND WHAT MAY EVENTUALLY BE A CUT OFF LOW OVER THE LOWER 
MISSISSIPPI VALLEY OR SOUTHEAST UNITED STATES MONDAY. 

MOISTURE BEGINS TO INCREASE ACROSS THE AREA ON FRIDAY BUT LITTLE IN 
THE WAY OF ANY ORGANIZED LIFT TO TRIGGER ANY PRECIPITATION ASIDE 
FROM DAILY THREAT OF AIRMASS TYPE SHOWERS AND THUNDERSTORMS. WITH 
LITTLE CHANGE IN THE AIR MASS THERE WILL BE MINIMAL CHANGES IN HIGH 
AND LOW TEMPERATURES EACH DAY. TEMPERATURES WILL BE NEAR NORMAL. NOT 
ANTICIPATING ANY EXTREMES.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AS OF 130 PM EDT MONDAY...

GUSTY SURFACE CONDITIONS WITH MAINLY VFR CONDITIONS PREVAIL ACROSS
THE AREA CURRENTLY. ISOLATED SHOWERS ARE ACROSS SOUTHEAST WEST
VIRGINIA. AS THE REMAINDER OF THE AFTERNOON PROGRESSES...SURFACE
WIND AND GUSTS WILL GRADUALLY DECREASE AS THE 850 MB SPEED MAX
EXITS THE REGION. WITH THE DEVELOPMENT OF THE NOCTURNAL
INVERSION...LIGHT WINDS ARE ANTICIPATED ACROSS THE REGION
OVERNIGHT. MOST OF THE SHOWERS WILL ALSO DISSIPATE AROUND SUNSET.

TONIGHT...WE EXPECT A RETURN OF MVFR CIGS AND SOME POCKETS OF MVFR
VSBYS ACROSS THE MOUNTAINS. ANY SUB-VFR CONDITIONS WILL RAPIDLY
IMPROVE TO VFR TUESDAY MORNING. SOME ISOLATED SHOWERS CANNOT BE
RULED OUT LATE TONIGHT INTO EARLY TUESDAY MORNING ACROSS THE
SOUTHWEST PART OF THE FORECAST AREA AS A WEAK DISTURBANCE SWEEPS
THROUGH THE OVERALL LONGWAVE TROUGH PATTERN.

EXTENDED AVIATION DISCUSSION...

PERSISTENT TROUGH PATTERN IN THE EAST WILL GRADUALLY RETROGRADE
WEST BY THE END OF THE WEEK. MAINLY VFR CONDITIONS ARE EXPECTED
THROUGH AT LEAST THURSDAY SAVE SOME LATE NIGHT EARLY MORNING
PATCHY MVFR FOG IN THE MOUNTAIN AND RIVER VALLEYS. AFTER
THURSDAY...WITH THE TROUGH AXIS FARTHER WEST...THIS WILL ALLOW FOR
A RETURN OF ATLANTIC MOISTURE AND A GREATER ABUNDANCE OF
SHOWERS...AND POTENTIALLY STORMS...IN THE FORECAST HEADING INTO
THE WEEKEND. THIS ALSO WILL ALLOW FOR INCREASED CHANCES OF SUB-VFR
CONDITIONS WITHIN THE AREA OF THE SHOWERS...AND THEN AGAIN
OVERNIGHT IN THE FORM OF LIGHT FOG OR STRATUS AS BOUNDARY MOISTURE
GETS TRAPPED UNDER THE NOCTURNAL INVERSION.

&&

.CLIMATE...

JULY 29TH RECORD LOWS:

ROANOKE......52...1925
BLUEFIELD....55...2013
DANVILLE.....58...1968
LEWISBURG....46...2013
LYNCHBURG....53...1920
BLACKSBURG...50...1983


JULY 30TH RECORD LOWS:

ROANOKE......54...1997
BLUEFIELD....50...1981
DANVILLE.....60...1972/81/83/2013
LEWISBURG....46...2013
LYNCHBURG....52...1997 
BLACKSBURG...50...1973/81


JULY 31ST RECORD LOWS:

ROANOKE......49...1914
BLUEFIELD....49...1997
DANVILLE.....55...1966
LEWISBURG....48...1997
LYNCHBURG....49...1997
BLACKSBURG...44...1997

&&

.EQUIPMENT...
THE NOAA WEATHER RADIO AT WYTHEVILLE VA...WZ2500...BROADCASTING
ON A FREQUENCY OF 162.450 MHZ...IS OFF THE AIR. TECHNICIANS HAVE
BEEN NOTIFIED. NO ESTIMATE FOR RETURN TO SERVICE.

&&

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

&&

$$
SYNOPSIS...DS
NEAR TERM...DS
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...DS
CLIMATE...DS/PH
EQUIPMENT...DS

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