Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 282312
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
712 PM EDT SAT MAR 28 2015

.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE SOUTHEAST
TONIGHT AND WILL BE CENTERED OVER THE MID ATLANTIC REGION SUNDAY.
A COLD FRONT OVER THE CENTRAL UNITED STATES ON SUNDAY WILL MOVE
EAST AND CROSS THROUGH THE REGION ON MONDAY.
&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 240 PM EDT SATURDAY...

1028 MB HIGH PRESSURE OVER GREAT LAKES REGION THIS AFTERNOON WILL
BUILD SOUTHEAST TONIGHT AND WILL BE CENTERED OVER THE MID ATLANTIC
REGION SUNDAY. GUSTY NORTHWEST WINDS WILL GRADUALLY DIMINISH THIS
EVENING AND BECOME LIGHT OVERNIGHT. PATCHY LOW STRATO CU WILL
CONTINUE TO MOVE SOUTH SOUTHEAST THIS AFTERNOON AND DISSIPATE
AFTER SUNSET.

UNDER HIGH PRESSURE...WINDS WILL DECOUPLE OVERNIGHT AND WITH SURFACE
DEWPOINTS IN THE TEENS AND SINGLE DIGITS...THE DRY AIR MASS WILL
RESULT IN GOOD RADIATIONAL COOLING UNDER MOSTLY CLEAR SKIES. RECORD
LOWS TEMPERATURES ARE POSSIBLE SUNDAY MORNING IN
LYNCHBURG...BLACKSBURG...DANVILLE...LEWISBURG AND BLUEFIELD.
(CLIMATE SECTION LISTED FOR REFERENCE AND ALSO NOTE THAT THE FROST
AND FREEZE PROGRAM HAS NOT BEGUN FOR OUR FORECAST AREA.)

AS THE HIGH CENTER SHIFTS SOUTHEAST...SOUTHERLY WINDS WILL
DEVELOP BY EARLY AFTERNOON AHEAD OF ANOTHER APPROACHING COLD
FRONT. DESPITE PLENTY OF SUNSHINE THROUGH MUCH OF THE DAY...UPPER
LEVEL TROUGHING ALONG THE ATLANTIC COAST WILL LIMIT HEATING.
PLAYED HIGH TEMPERATURES CLOSER TO COOLER ADJMET VALUES FROM THE
THE LOWER 40S IN THE NORTHWEST MOUNTAINS TO THE LOWER 50S IN THE
PIEDMONT.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 305 PM EDT SATURDAY...

EXPECT A FRONT TO MOVE ACROSS FROM THE NORTHERN STREAM SUNDAY NIGHT
INTO MONDAY WITH MAINLY A THREAT OF SHOWERS. SOME COLDER AIR WILL
SNEAK IN ACROSS THE ALLEGHANYS AND COULD PRODUCE SNOW...BUT NOTHING
OF SIGNIFICANCE.

ONCE THIS FRONT PASSES THE FLOW ALOFT STAYS A GENERAL WNW PATTERN.
ANOTHER SHORTWAVE ARRIVES BY TUESDAY ALTHOUGH MAIN MOISTURE WILL
STAY NORTH OF US. EXPECT MODERATING TEMPERATURES THIS PERIOD WITH
LOWS AND HIGHS CLOSER TO NORMAL FOR LATE MARCH.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM EDT SATURDAY...

MODELS VARY IN TERMS OF THE SOUTHERN STREAM SYSTEM MOVING TOWARD OUR
AREA BY THE END OF THE WEEK. BOTH 00Z/12Z ECMWF SHOW MORE
AMPLIFICATION WITH UPPER SHORTWAVE OVER THE RED RIVER VALLEY OF TX
WEDNESDAY WHICH IN A SPLIT FLOW APPEARS TO TAKE ON MORE NEGATIVE
TILT HEADING INTO THURSDAY OVER THE TN VALLEY. HPC APPEARS TO BE
LEANING TOWARD A BLEND OF THE TWO MODELS/ENSEMBLE APPROACH. THIS
WILL DICTATE WHEN RAIN MOVES ACROSS OUR AREA.

BEFORE THIS SYSTEM...SFC HIGH SHOULD WEDGE SWD BRIEFLY WEDNESDAY
WITH SEASONABLY MILD DAY ON TAP. THIS HIGH DEPARTS THE MID ATLANTIC
COAST THURSDAY MORNING...WITH SURGE OF MOISTURE PUSHING NWD ALONG
THE BLUE RIDGE PER SE FLOW. AT THIS TIME...THINK WILL SEE DRIER AIR
WITH LIMITED THREAT OF RAIN WED NIGHT BUT EXPECT AIRMASS TO MOISTEN
MORE INTO THURSDAY AFTERNOON WITH MAIN LIFT STAYING WEST OF THE
APPALACHIANS. STILL LOOKING AT THE CHANCE OF RAIN FROM ALONG AND WEST
OF THE BLUE RIDGE...WITH POSSIBLY EWD EXTENT INTO THE SOUTHERN CWA
PER FLOW OFF THE ATLANTIC EARLY ON BEFORE VEERING WINDS TURN MORE SW.

HIGHS THURSDAY WILL BE MILD BUT COULD BE COOLER PER MORE CLOUDS AND
RAIN CHANCES. IF THE HIGH SLOWS DOWN OR SHIFTS FURTHER NORTH...THUS
ALLOWING LONGER EASTERLY FETCH...THEN TEMPS COULD BE 5-10 DEGREES
COOLER OUT EAST....BUT STILL JUST NEAR NORMAL.

AS WE HEAD INTO THURSDAY NIGHT-FRIDAY THE FORECAST VARIES...THOUGH
THE NEW 12Z ECMWF SHOWS SIMILAR SETUP THAT THE 12Z GFS DOES WITH
FRONT ORIENTATION SETTING UP IN AN EAST-WEST FASHION WITH PARALLEL
FLOW ALOFT. THIS IS GOING TO KEEP THE AREA IN A UNSETTLED PATTERN
WITH NEXT MAIN LOW ACROSS THE CENTRAL PLAINS FRIDAY ARRIVING OVER
THE OHIO VALLEY/CENTRAL APPALACHIANS FRIDAY AFTERNOON/EVENING. THE
DIFFERENCE IN THE MODELS IS THAT THE ECMWF SHOWS A STRONGER LOW
MOVING MORE NORTH OVER THE GREAT LAKES...WHILE THE GFS HAS WEAKER
LOW MOVING ACROSS WV INTO NRN VA. THE ECMWF SOLUTION AS SUCH HAS
LESS QPF THAN THE GFS. NONETHELESS THREAT OF RAIN SHOWERS WILL
CONTINUE INTO SATURDAY. THE AIRMASS BEHIND THE FRONT WILL BE COLD
THOUGH THE ECWMF IS MUCH MORE AMPLIFIED AND COLDER THAN THE GFS.
COULD SEE UPSLOPE SNOW SHOWERS IN THE MTNS SATURDAY NIGHT.
&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 650 PM EDT SATURDAY...

HIGH PRESSURE WILL PROVIDE VFR CONDITIONS TONIGHT THROUGH SUNDAY.
ONGOING GUSTY NORTHWEST WINDS SHOULD DIMINISH THIS EVENING AND
BECOME LIGHT AFTER MIDNIGHT INTO SUNDAY MORNING. WINDS WILL THEN
TURN MORE SOUTHWEST SUNDAY AFTERNOON AS HIGH PRESSURE SLIDES TO
THE SOUTH WITH SPEEDS INCREASING TO BETWEEN 8-15 KNOTS LATER IN
THE DAY.

HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE
TAF PERIOD.

EXTENDED AVIATION FORECAST...

A COLD FRONT WILL PASS SOUTHEAST THROUGH THE REGION LATER SUNDAY
NIGHT AND EARLY MONDAY POSSIBLY BRINGING A PERIOD OF MVFR CIGS
ALONG WITH A BAND OF SHOWERS TO THE MOUNTAINS. THERE IS ALSO
POTENTIAL FOR STRONG GUSTY WINDS BEHIND THE FRONT MONDAY AND
AGAIN TUESDAY AS ANOTHER CLIPPER SLIDES ACROSS FROM THE NORTHWEST.
OTHERWISE WEAK HIGH PRESSURE SHOULD MAINTAIN MAINLY VFR TUESDAY
INTO WEDNESDAY WITH ONLY LINGERING MOUNTAIN UPSLOPE DRIVEN MVFR
CIGS ON TUESDAY. MOISTURE WILL AGAIN INCREASE AHEAD OF A STRONGER
COLD FRONT THURSDAY WITH A RETURN TO SUB-VFR CONDITIONS POSSIBLE FOR
MOST TAF SITES BY THEN.
&&

.CLIMATE...
AS OF 455 AM EDT FRIDAY...

RECORD LOWS FOR MARCH 29:

ROANOKE......19 IN 1982
BLACKSBURG...17 IN 2001
LYNCHBURG....23 IN 1923 AND 1982
DANVILLE.....23 IN 1966
BLUEFIELD....19 IN 1966 AND 1982
LEWISBURG....18 IN 1983

&&

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

&&

$$
SYNOPSIS...KK
NEAR TERM...KK
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/JH/KK
CLIMATE...AMS/SK



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