-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 211627
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1227 PM EDT MON APR 21 2014

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL LINGER OVER THE AREA THROUGH THIS
AFTERNOON...KEEPING WARM AND DRY WEATHER IN PLACE. A COLD FRONT
OVER THE UPPER MIDWEST WILL SWEEP SOUTHEAST THROUGH THE AREA ON
TUESDAY...PRECEDED AND ACCOMPANIED BY SCATTERED SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE IS EXPECTED TO RETURN TO THE AREA ON
WEDNESDAY...BRINGING BLUSTERY AND COOLER WEATHER.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM EDT MONDAY...

BASICALLY A TEMP FORECAST THROUGH THE AFTERNOON GIVEN VERY DRY AIR
IN PLACE PER MORNING RAOBS AND UNDER THE LINGERING RIDGE. MAY SEE
SOME HIGH/MID CLOUDS WORK INTO THE WEST LATER ON...OTRW STAYING
SUNNY/WARMER THAN SUNDAY PER WARMING ALOFT AND STRONG HEATING.
ALTHOUGH ACTUAL THICKNESS NUMBERS GIVING HIGHS A CAT OR SO BELOW
MOS...LATEST LOCAL SCHEME VALUES SUPPORT CLOSER TO THE WARMER MAV
FORECAST HIGHS. THIS DESPITE ONLY LIGHT MIXING WHICH MAY ACTUALLY
KEEP THE SE COOLER WHERE MORE OF A LIGHT NE TRAJECTORY WILL
PERSIST. THUS ADJUSTED HIGHS UP CENTRAL AND WEST WHERE MORE ON THE
ORDER OF MID 70S LIKELY WITH PERHAPS A FEW LATE DAY UPPER 70S
POSSIBLE.

PREVIOUS DISCUSSION AS OF 300 AM EDT MONDAY...

SURFACE RIDGE OF HIGH PRESSURE WILL LINGER OVER THE BLACKSBURG
FORECAST AREA TODAY...BRINGING MOSTLY SUNNY AND WARM TEMPERATURES.
850 MILLIBAR TEMPERATURES ARE FORECAST TO RISE 8C ACROSS THE
PIEDMONT...AND 3-4C ACROSS THE MOUNTAINS WITH RESPECT TO
YESTERDAY...AND DESPITE SOME HIGH LEVEL CLOUDS...SHOULD BE
SUFFICIENT TO SUPPORT DAYTIME HIGHS IN THE 70S IN MOST
LOCATIONS...EXCLUDING HIGHER ELEVATIONS WHERE TEMPERATURES WILL BE
HARD PRESSED TO CLIMB OUT OF THE 60S.

NEXT UPSTREAM SHORT WAVE TROF AND ASSOCIATED INCREASE IN MID LEVEL
CANOPY WILL BEGIN TO IMPACT THE REGION TONIGHT. DESPITE RELATIVELY
LOW DEW POINTS AND NEARLY CALM WINDS...INCREASING CLOUDS SHOULD
CUT BACK ON EXTENT OF RADIATIVE COOLING SUCH THAT MOST AREAS FALL
BACK ONLY INTO THE 40S.

LEADING EDGE OF SCATTERED SHOWERS IN ADVANCE OF NEXT COLD FRONT MAY
ENCROACH THE WESTERN PORTION OF THE BLACKSBURG FORECAST AREA TOWARD
DAYBREAK ON TUESDAY...BUT MAIN IMPACT OF THIS NEXT SYSTEM WILL OCCUR
AFTER DAYBREAK.
&&

.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EDT MONDAY...

THE MAIN FEATURE DURING THIS PORTION OF THE FORECAST IS A COLD FRONT
THAT WILL CROSS THE REGION ON TUESDAY. LATEST MODEL GUIDANCE OFFERS
SOLUTIONS THAT HIGHLIGHT THE BEST COVERAGE DURING THE MORNING ACROSS
THE WESTERN HALF OF THE AREA. BY THE AFTERNOON...THE BEST COVERAGE
JUMPS TO ALONG THE SOUTHERN AND SOUTHEASTERN PARTS OF THE REGION
WITH A QUICKER PROGRESSION OF DRYING IN THE WEST AS COMPARED TO
GUIDANCE OF 12 HOURS AGO. THE LATEST ADJUSTMENTS HAVE BEEN
INCORPORATED INTO THE FORECAST PACKAGE FOR THIS MORNING. WE WILL
CONTINUE TO MENTION THE POTENTIAL FOR A SLIGHT CHANCE OF
THUNDERSTORMS COINCIDENT TO AND JUST IN ADVANCE OF THE FRONT FROM
MIDDAY THROUGH THE AFTERNOON.

COOLER AND DRIER HIGH PRESSURE WILL WORK ITS WAY INTO THE AREA IN
THE WAKE OF THE FRONT AND BE SETTLED OVER THE REGION BY WEDNESDAY
NIGHT. INITIALLY...THE PRESSURE GRADIENT BETWEEN THE TWO SYSTEM WILL
HELP PROMPT GUSTY WINDS TUESDAY NIGHT THROUGH WEDNESDAY. AT THIS
POINT THE STRONGEST GUSTS LOOK TO BE AT THE HIGHEST ELEVATIONS IN
THE 25 TO 30 MPH RANGE. EAST OF THE BLUE RIDGE...GUSTS WILL BE MORE
ON THE ORDER OF 15 TO 20 MPH.

LATE WEDNESDAY NIGHT INTO THURSDAY...THE COLDEST AIR WILL BE ACROSS
THE REGION WITH MID TO UPPER 30S FOR LOWS ACROSS THE MOUNTAINS AND
UPPER 30S TO LOWER 40S ACROSS THE PIEDMONT. THERE MAY BE SOME PATCHY
FROST ACROSS PARTS OF SOUTHEAST WEST VIRGINIA AND NEIGHBORING PARTS
OF SOUTHWEST VIRGINIA. HOWEVER...THE GROWING SEASON STILL HAS NOT
STARTED IN THIS PARTS...SO NO FROST ADVISORIES ARE ANTICIPATED.

THE NEXT COLD FRONT TO IMPACT OUR REGION IS NOT EXPECTED TO ARRIVE
UNTIL FRIDAY. HOWEVER...MOISTURE IN ADVANCE OF THE FRONT WILL YIELD
TO INCREASING CLOUD COVER THURSDAY NIGHT...WITH THE POTENTIAL FOR
SOME ISOLATED TO SCATTERED SHOWERS ACROSS THE MOUNTAINS BY DAYBREAK
FRIDAY.
&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 1245 PM EDT SUNDAY...

MODERATING TEMPERATURES ARE EXPECTED ON FRIDAY AS LOW LEVEL WINDS
STRENGTHEN FROM THE SOUTHWEST AND WARM AIR ADVECTION PREDOMINATES.
A COLD FRONT WILL APPROACH THE AREA FRIDAY MORNING AND BE EAST OF
THE AREA BY FRIDAY EVENING. SCATTERED SHOWERS AND SOME ISOLATED
THUNDERSTORMS WILL ACCOMPANY THE FRONT.

BEHIND THE FRONT...MODEL GUIDANCE DEVIATES ENOUGH TO PROVIDE
UNIQUELY DIFFERENT WEATHER PATTERN SOLUTIONS FOR OUR REGION OF
THE COUNTRY. THE GFS SOLUTION DEEPENS THE PARENT LOW OF THE COLD
FRONT AND BRINGS IT SOUTH TO CAPE COD BY SUNDAY MORNING. THIS
KEEPS A PREVAILING NORTHWEST FLOW WHICH IS DRY AND PROGRESSIVELY
COOLER ACROSS THE AREA. THE ECMWF DOES NOT DEEPEN THE COLD FRONT/S
PARENT LOW...AND EJECTS ITS QUICKLY EASTWARD MORE AS AN OPEN WAVE.
THIS ALLOWS FOR A QUICKER RETURN OF ZONAL FLOW TO THE AREA THAT
HAVE THE POTENTIAL TO BRING CENTRAL U.S. SYSTEMS INTO OR TOWARD
THE AREA BY THE END OF THE WEEKEND...ALONG WITH HAVING A MILDER
PATTERN. OUR FORECAST WILL REFLECT THE GUIDANCE PROVIDED BY WPC
WHICH LEANS MORE CLOSELY TO THE ECWMF SOLUTION.

&&

.AVIATION /16Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 1210 PM EDT MONDAY...

WIDESPREAD VFR CONDITIONS WITH NO FLIGHT RESTRICTIONS ARE EXPECTED
TO CONTINUE THROUGH TONIGHT AS SURFACE HIGH PRESSURE CURRENTLY
OVER THE MID ATLANTIC STATES MOVES SLOWLY OFFSHORE. WILL SEE SOME
INCREASE IN MID CLOUDS AND PERHAPS SOME STRATO-CU OVER SE WEST VA
LATE TONIGHT BUT STILL DRY OVERNIGHT.

A COLD FRONT WILL APPROACH FROM THE WEST BY EARLY TUESDAY AND PASS
ACROSS THE AREA ON TUESDAY...LIKELY PRECEDED AND ACCOMPANIED BY
SCATTERED SHOWERS/THUNDERSTORMS ALONG WITH LOCALIZED MVFR FLIGHT
RESTRICTIONS. HOWEVER APPEARS THE BEST SHOT AT SEEING MVFR CIGS
AND/OR VSBYS SHOULD BE OVER BLF/LWB WITH ONLY LIGHTER SHOWERS OUT
TO THE BLUE RIDGE TUESDAY MORNING...FOLLOWED BY REDEVELOPMENT OF
MORE ISOLATED SHRA/TSRA ALONG THE LYH-DAN CORRIDOR TUESDAY
AFTERNOON. THEREFORE ONLY ADDED MVFR CIGS TO THE SE WVA LOCATIONS
WITH INCLUSION OF VFR VSBY RESTRICTIONS THERE AS WELL.

THE FRONT WILL EXIT THE REGION BY TUESDAY NIGHT...RESULTING IN A
RETURN TO VFR WEATHER AND GUSTY NW WINDS TUESDAY NIGHT INTO
WEDNESDAY...EXCEPT FOR THE POTENTIAL OF SOME MVFR CIGS LINGERING
OVER THE FAR WESTERN UPSLOPE SITES IN SE WEST VA.

EXTENDED AVIATION DISCUSSION...

HIGH PRESSURE WILL THEN BUILD INTO AND OVER THE REGION ON
THURSDAY...WITH WIDESPREAD VFR LIKELY. ANOTHER FAST MOVING COLD
FRONT WILL ARRIVE ON FRIDAY...WITH A BRIEF PERIOD OF MVFR
RESTRICTIONS POSSIBLE AS SHOWERS/ISOLATED STORMS MOVE EAST WITH
THE FRONT THROUGH THE AREA.
-- End Changed Discussion --
&&

.FIRE WEATHER...
AS OF 935 AM EDT MONDAY...

LOW HUMIDITY WILL AGAIN BE AN ISSUE THROUGH THIS AFTERNOON AS
HEATING AND ONLY GRADUAL MOISTURE RETURN SET THE STAGE FOR LEVELS
TO FALL BELOW 25-30 PERCENT AGAIN...AND PERHAPS AS LOW AS 15
PERCENT OVER THE MOUNTAINS. HOWEVER WINDS WILL BE MUCH LIGHTER
THAN THOSE SEEN ON SUNDAY WITH A GRADUAL INCREASE TO AROUND 10
MPH FROM THE WEST AND SOUTHWEST LATER IN THE AFTERNOON. ALTHOUGH
THE LOW HUMIDITY WILL ALLOW FOR EXCELLENT DRYING THIS AFTERNOON...
LIGHT AND ERRATIC WINDS MAY POSE SOME TRANSPORT ISSUES FOR
SCHEDULED PRESCRIBED BURNS DUE TO THE VARIABILITY OF THE LOW LEVEL
FLOW.

ADDITIONAL OPPORTUNITIES FOR PRESCRIBED BURNS WHERE GOOD DRYING
CONDITIONS WILL EXIST...AND WHERE TRANSPORT WINDS WILL BE MORE
FAVORABLE DUE TO BETTER TRANSPORT AND CONSISTENCY OF DIRECTION
WILL OCCUR LATE WEDNESDAY AFTERNOON...WITH AN EVEN MORE OPTIMAL
CONDITION EXPECTED ON THURSDAY.
&&

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

&&

$$
SYNOPSIS...JH/WERT
NEAR TERM...JH/WERT
SHORT TERM...DS
LONG TERM...DS
AVIATION...JH/RAB/WERT
FIRE WEATHER...JH/WERT