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533
FXUS62 KRAH 220112
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
912 PM EDT TUE OCT 21 2014

.SYNOPSIS....AN UPPER LEVEL LOW WILL MOVES THROUGH THE MID-ATLANTIC
STATES TONIGHT. THE LOW PRESSURE SYSTEM WILL INTENSIFY WHILE IT
TRACKS SLOWLY NORTHEAST UP THE MID ATLANTIC COAST COAST WEDNESDAY
THROUGH THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 912 PM TUESDAY...

SURFACE COLD FRONT CURRENTLY LOCATED MOVING INTO THE NC COASTAL
PLAIN WILL EXIT THE AREA SHORTLY...IN ADVANCE OF AN UPPER LEVEL LOW
DIVING SEWD INTO SOUTHERN VA/NORTHEAST NC. ISOLATED SHOWERS HAVE
DEVELOPED ALONG THE FRONT...NEAR THE VA/NC BORDER...JUST EAST OF
INTERSTATE 95. OTHERWISE...FROPA ACROSS THE FORECAST AREA THIS PAST
EVENING HAS BEEN DRY WITH ACCOMPANYING BROKEN/OVERCAST MID CLOUD
DECK SPREADING EASTWARD.

WITH THE EXCEPTION OF THE FAR NE ZONES...SKIES ARE EXPECTED TO CLEAR
OUT IN THE WAKE OF THE FROPA. BREEZY CONDITIONS ARE EXPECTED BEHIND
THE FRONT WITH NWLY WIND GUSTS INTO THE UPPER TEENS WELL INTO THE
NIGHT. AS SUCH...CAA WILL GOVERN OVERNIGHT LOWS RANGING IN THE MID
40S OVER THE WEST TO THE UPPER 40S/AROUND 50 EAST.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 307 PM TUESDAY...

WEDNESDAY... AN UPPER LEVEL FLOW OVER THE NORTHERN MID ATLANTIC WILL
MAINTAIN A STRONG CYCLONIC FLOW OVER CENTRAL NC. PERTURBATIONS
WITHIN THIS FLOW IN CONJUNCTION WITH AVAILABLE MOISTURE WILL CAUSE
PERIODS OF CLOUDINESS...MAINLY ACROSS THE NE HALF THROUGH EARLY
WEDNESDAY EVENING. STEEP MID LEVEL LAPSE RATES (7-7.5 DEG C/KM)
COUPLED WITH AFTERNOON HEATING MAY TRIGGER AN ISOLATED SHOWER OR
TWO...MAINLY IN VICINITY OF ROANOKE RAPIDS/WARRENTON AND TARBORO.
FARTHER SOUTH AND EAST...AIR MASS APPEARS TOO DRY TO SUPPORT
ANYTHING MORE THAN A FEW CLOUDS.

N-NW WINDS WILL REMAIN A LITTLE BLUSTERY WITH GUSTS AROUND 25 MPH
POSSIBLE.

LOW LEVEL CAA MORE PRONOUNCED WITH THERMAL TROUGH OVER THE REGION.
AFTERNOON TEMPS WILL STRUGGLE TO REACH THE LOWER 60S IN THE NW WITH
MID-UPPER 60S COMMON ELSEWHERE.

WEDNESDAY NIGHT...UPPER LEVEL LOW BEGINS TO PULL OUT WEDNESDAY
NIGHT. MID LEVEL SUBSIDENCE IN ITS WAKE WILL RID ARE AREA OF ANY
LINGERING SHOWERS AND CLOUDINESS. LOW LEVEL MIXING WILL
PERSIST...AIDING TO MAINTAIN OVERNIGHT TEMPS. OF SFC WINDS WERE TO
DECOUPLE (MAINLY WESTERN-SOUTHERN PIEDMONT)...COULD SEE MIN TEMPS AS
LOW AS THE MID 30S AT A FEW SPOTS. FOR NOW WILL BOTTOM OUT TEMPS IN
THE UPPER 30S IN THE WESTERN-SOUTHERN PIEDMONT WITH IN TEMPS IN THE
LOW-MID 40S ELSEWHERE.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...

THURSDAY THROUGH FRIDAY NIGHT: WEAK SHORTWAVE RIDING WILL BRIEFLY
APPROACH/BUILD OVER THE AREA. NEAR TERM MODEL GUIDANCE IN GOOD
AGREEMENT IN THE DEVELOPMENT/MOVEMENT OF AN UPPER LEVEL LOW ACROSS
THE NORTHERN MID ATLANTIC LATE TONIGHT-EARLY WED. THE CIRCULATION
AROUND THIS DEVELOPING SYSTEM SHOULD MAINTAIN VARYING CLOUDINESS
NEAR THE VIRGINIA BORDER UNTIL LATE TONIGHT WITH PARTIAL CLEARING
TOWARD MORNING. 850MB THERMAL TROUGH POSITIONED TO OUR NW TONIGHT
WITH BETTER LOW LEVEL ADVECTION ON THURSDAY INTO THURSDAY NIGHT AS THE DEEP
MID LEVEL LOW SLOWLY CONTINUES TO LIFT OFF TO THE NORTHEAST. THIS
WILL YIELD MOSTLY SUNNY/SUNNY SKIES-CLEAR/MOSTLY CLEAR SKIES.
HOWEVER... WITH THE DEPARTING SYSTEM... WE MAY SEE SUSTAINED
NORTHWESTERLY WINDS IN THE 10 TO 15 MPH RANGE... WITH SOME GUSTS OF
AROUND 20 MPH OR SO DURING THE DAYLIGHT HOURS OF THURSDAY. AFTERNOON
LOW LEVEL THICKNES VALUES AREA EXPECTED TO BE IN THE 1350S TO 1360S.
THUS... GIVEN FULL SUN IS EXPECTED ALONG WITH SOMEWHAT OF A
DOWNSLOPE FLOW WILL GO WITH HIGH TEMPS RANGING FROM THE MID TO UPPER
60S. LOWS THURSDAY NIGHT WITH CLEAR/MOSTLY CLEAR SKIES AND A
WEAKENING WIND ARE EXPECTED TO BE IN THE LOWER TO MID 40S... WITH A
FEW UPPER 30S NOT OUT OF THE QUESTION IN THE USUAL RURAL COLD SPOTS.

ONE LAST S/W DISTURBANCE IS FORECAST TO TRACK SOUTHEASTWARD FROM THE
NORTHERN PLAINS/UPPER MIDWEST ON THURSDAY AND MOVE ACROSS CENTRAL NC
ON FRIDAY INTO FRIDAY NIGHT. THE ECMWF CONTINUES TO BE MUCH STRONGER
WITH THIS FEATURE THAN THE GFS AND NAM. HOWEVER... WITH SUCH A DRY
AIRMASS IN PLACE PRECEDING THE FEATURE AND LACK OF ANY REAL MOISTURE
RETURN IN ADVANCE OF IT MODELS DO NOT SHOW ANY PRECIP BEING
GENERATED ACROSS CENTRAL NC AS IT ACROSS THE AREA. THUS... WILL JUST
SHOW AN INCREASE IN CLOUD COVER ON FRIDAY. HOW STRONG THE SYSTEM
ENDS UP BEING WILL HAVE AN AFFECT ON HIGH TEMPS THOUGH (WITH CLOUD
COVER BEING THE VARIABLE IN QUESTION). FOR NOW WILL JUST SHOW PARTLY
SUNNY SKIES ON FRIDAY... WITH HIGH TEMPS IN THE UPPER 60S TO NEAR 70
SOUTH. LOWS FRIDAY NIGHT WITH CLEARING SKIES ARE EXPECTED TO BE IN
THE 40S.

SATURDAY THROUGH TUESDAY: QUITE WEATHER IS EXPECTED TO CONTINUE FOR
THE UPCOMING WEEKEND AND INTO NEXT WEEK. MID LEVEL RIDGING IS
FORECAST TO BUILD OVER THE AREA FROM THE CENTRAL U.S. BY EARLY NEXT
WEEK... YIELDING A WARMING TREND. EXPECT TEMPS WILL BE NEAR NORMAL
TEMPS TO START THE PERIOD... INCREASING TO HIGH TEMPS A CATEGORY OR
TWO ABOVE NORMAL BY EARLY NEXT WEEK. THIS YIELDS HIGH TEMPS THIS
WEEKEND AROUND 70/LOWER 70S... WITH TEMPS WARMING TO THE LOWER TO
MID 70S BY MONDAY AND TUESDAY... WITH POSSIBLY SOME UPPER 70S BY
TUESDAY. GIVEN THE PATTERN CHANCE TO RIDING ALOFT... SKIES ARE
EXPECTED TO GENERALLY BE MOSTLY SUNNY/MOSTLY CLEAR FOR THIS ENTIRE
PERIOD. THIS SHOULD YIELD A NICE DIURNAL TEMP RANGE... GIVEN THE DRY
CONDITIONS AND RATHER LIGHT WINDS EXPECT FROM SUNDAY ONWARD. LOWS
ARE EXPECTED TO BE IN THE 40S... TO AROUND 50 ACROSS OUR FAR
SOUTHEAST BY EARLY NEXT WEEK.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 750 PM TUESDAY...

VFR CONDITIONS WILL PERSIST THROUGH THE CURRENT TAF PERIOD. A COLD
FRONT IS MAKING ITS WAY THROUGH THE FORECAST AREA THIS EVENING AND
WILL CLEAR THE REGION IN THE NEXT COUPLE OF HOURS. SOME CLOUDS WILL
ACCOMPANY THE FRONT...BUT WILL REMAIN IN THE VFR RANGE. WINDS WILL
BECOME NORTH/NORTHWESTERLY BEHIND THE FRONT AND ADDITIONALLY THERE
COULD BE A BRIEF PERIOD OF GUSTINESS. A COUPLE OF SHOWERS WERE NOTED
NEAR THE VA BORDER AND THIS IS WHERE THE ISOLATED COVERAGE IS
EXPECTED TO REMAIN...ALTHOUGH CANNOT COMPLETELY RULE OUT A SHOWER OR
TWO IN CENTRAL NC...ESPECIALLY ACROSS THE NORTHEAST. THEN...WINDS ARE
EXPECTED TO INCREASE WEDNESDAY MORNING...WITH GUSTS UP TO 25 MPH
POSSIBLE. ALSO...AN UPPER LEVEL LOW OVER THE NORTHERN MID ATLANTIC
MAY CAUSE PERIODS OF CLOUDINESS WITH CEILINGS 3500-5000FT...MAINLY
IN VICINITY OF KRDU AND KRWI DUE TO THE PROXIMITY OF THE LOW. THIS
FEATURE MAY ALSO RESULT IN A SHOWER OR TWO...MOST LIKELY ACROSS THE
NORTHEAST (IN THE VICINITY OF KRWI)...BUT ESPECIALLY CLOSER TO THE
VIRGINIA BORDER.

OUTLOOK...A HIGH PROBABILITY OF VFR CONDITIONS WILL PERSIST THURSDAY
THROUGH SUNDAY. THE UPPER LEVEL LOW IS PROJECTED TO LIFT TO THE NE
THURSDAY AND THURSDAY NIGHT. THIS WILL ALLOW AN AREA OF HIGH
PRESSURE TO BUILD THEN SETTLE OVER CENTRAL NC THROUGH THE WEEKEND.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...CBL
NEAR TERM...CBL/WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...KRD/WSS




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