Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KRNK 290540
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
140 AM EDT SUN MAR 29 2015

.SYNOPSIS...
HIGH PRESSURE IN THE OHIO VALLEY WILL MOVE SOUTHEAST ACROSS THE
REGION OVERNIGHT BEFORE SLIDING TO THE SOUTH ON SUNDAY. A COLD
FRONT OVER THE CENTRAL UNITED STATES ON SUNDAY WILL MOVE EAST AND
CROSS THROUGH THE AREA EARLY MONDAY. WEAK HIGH PRESSURE WILL
FINALLY BUILD INTO THE REGION BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 855 PM EDT SATURDAY...

MAIN UPDATE TO ADJUST LOW TEMPS OVERNIGHT GIVEN AN ARID PWAT OF
.07 OFF THE EVENING RNK SOUNDING AND VERY LOW DEWPOINTS AHEAD OF
HIGH PRESSURE BUILDING OVER THE MOUNTAINS BY DAYBREAK. THIS
RIDGING SHOULD ALLOW JUST ENOUGH DECOUPLING ESPCLY VALLEYS UNDER
CLEAR SKIES TO SEND MOST LOWS INTO THE TEENS WEST WITH A FEW
SINGLE DIGITS POSSIBLE. BREEZE MAY STAY UP JUST LONG ENOUGH TO
KEEP TEMPS FROM BOTTOMING OUT IN THE EAST BUT STILL UPPER TEENS TO
LOWER 20S PIEDMONT. THUS CUTTING LOWS A CAT OR TWO IN THE WESTERN
VALLEYS AND A FEW DEGREES IN SPOTS OVER THE EAST. OTHERWISE ONLY
SMALL CHANGES TO REDUCE WINDS A BIT MORE LATER TONIGHT ESPCLY
UNDER THE CENTER OF THE SURFACE RIDGE AROUND DAYBREAK.

PREVIOUS DISCUSSION 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 /TONIGHT 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 /06Z SUNDAY THROUGH THURSDAY/...
AS OF 135 AM EDT SUNDAY...

HIGH PRESSURE OVER THE OHIO VALLEY WILL MOVE SOUTHEAST TODAY AND
OFF THE CAROLINA COAST TONIGHT. A COLD FRONT WILL CROSS THROUGH
THE REGION FROM THE WEST LATE TONIGHT.

SURFACE WINDS WILL BE LIGHT AND VARIABLE THIS MORNING THEN
INCREASE FROM THE SOUTH-SOUTHWEST THIS AFTERNOON AND EVENING.
HIGHER ELEVATIONS MAY HAVE GUSTS UP TO 30 KNOTS JUST AHEAD OF THE
FRONT. WINDS WILL SHIFT TO THE WEST THEN NORTHWEST BEHIND THE
BOUNDARY. HIGH

HIGH CLOUDS WILL SPREAD ACROSS THE AREA AHEAD OF THE
FRONT...MAINLY AFTER 00Z/8PM. HIGH CONFIDENCE IN VFR CONDITIONS
DURING THE TAF PERIOD.

EXTENDED AVIATION FORECAST...

A PERIOD OF MVFR CIGS ALONG WITH A BAND OF SHOWERS IS POSSIBLE IN
THE MOUNTAINS LATE SUNDAY NIGHT AND MONDAY MORNING.

THERE IS ALSO POTENTIAL FOR STRONG GUSTY WINDS BEHIND THE FRONT
MONDAY AND AGAIN TUESDAY AS ANOTHER CLIPPER SLIDES ACROSS FROM THE
NORTHWEST.

WEAK HIGH PRESSURE SHOULD MAINTAIN MAINLY VFR CONDITIONS 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.

&&

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.