Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 271815
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
215 PM EDT FRI MAR 27 2015

.SYNOPSIS...A COLD FRONT WILL MOVE OFF THIS COAST THIS MORNING.
TRAILING THE FRONT...A POTENT UPPER LEVEL TROUGH WILL MOVE THROUGH
THE REGION THIS EVENING AND OVERNIGHT. DRY HIGH PRESSURE WILL BUILD
INTO THE REGION OVER THE WEEKEND.

&&

.NEAR TERM /TODAY AND TONIGHT/...
AS OF 950 AM FRIDAY...

TODAY: COLD FRONT IS IN THE PROCESS OF PUSHING SOUTH OF THE
AREA...AND WILL MOVE OFF THE SE NC COAST AOA MIDDAY...SLOWING DOWN
IN THE PROCESS OWING TO THE APPROACH OF THE AMPLIFYING UPPER LEVEL
TROUGH DIGGING SOUTHWARD INTO THE SOUTHERN APPALACHIANS. GIVEN
PLENTIFUL MOISTURE...MARGINAL ELEVATED INSTABILITY...AND INCREASING
DEEP-LAYER FORCING IN ADVANCE OF THE AMPLIFYING TROUGH...LARGE BAND
OF ANAFRONTAL SHOWERS WILL PROGRESS SLOWLY EASTWARD ACROSS THE
FORECAST AREA FOR MUCH OF THE DAY...ESP IN THE COASTAL PLAIN WHERE
PRECIP IS EXPECTED TO LINGER INTO THE 21-00Z TIME FRAME. TEMPERATURES
BEHIND THE FRONT DROP A GOOD 15 DEGREES...AND GIVEN OVERCAST SKIES...
CONTINUED COLD ADVECTION...AND PRECIPITATION/EVAP COOLING/...MOST AREAS
HAVE ALREADY SEEN THEIR HIGH FOR TODAY...WITH RATHER UNIFORM
TEMPERATURES THIS AFTERNOON IN THE MID 40S. THE EXCEPTION COULD BE
ACROSS THE WESTERN PIEDMONT WHERE CLOUD COVER MAY THIN ENOUGH FOR
TEMPS TO RISE SEVERAL DEGREES TO NEAR 50 DEGREES.

TONIGHT: THE AMPLIFYING UPPER LEVEL TROUGH WILL PROGRESS ACROSS THE
CAROLINAS LATE THIS EVENING INTO TONIGHT. STRONG DPVA /LAYER
LIFTING/ AND COLD ADVECTION ALOFT (H7 TEMPS FALLING 10C BETWEEN 21Z-
03Z IN THE TRIAD) WILL RESULT IN MARGINAL NOCTURNAL DESTABILIZATION
AND A POTENTIAL FOR ISOLD TO SCT LOW-TOPPED SHOWERS FROM WEST-EAST IN
THE 02-08Z TIME FRAME. THE LATEST GUIDANCE SUGGESTS THAT LOW-LEVEL
THERMAL PROFILES WILL BE EXCLUSIVELY SUPPORTIVE OF RAIN DURING THE
TIME-FRAME IN WHICH SHOWER ACTIVITY WILL BE POSSIBLE. LOWS WILL BE
DRIVEN BY A COMBINATION OF COLD ADVECTION AND RADIATIONAL COOLING
BETWEEN 06-12Z AS SYNOPTIC SUBSIDENCE /CLEARING/ COMMENCES IN THE
WAKE OF THE UPPER LEVEL TROUGH AND THE MSLP GRADIENT TIGHTENS.
EXPECT LOWS RANGING FROM 33-36F IN THE NW PIEDMONT TO NEAR 40F IN
THE SE COASTAL PLAIN.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...

SATURDAY: STRONG SYNOPTIC SUBSIDENCE AND LOW-LEVEL COLD ADVECTION IN
THE WAKE OF THE UPPER LEVEL TROUGH WILL ENSURE MOSTLY CLEAR SKIES
AND WELL BELOW NORMAL HIGHS ON SAT...RANGING FROM THE LOWER 40S IN
THE N/NW PIEDMONT TO NEAR 50F IN THE SE COASTAL PLAIN. -VINCENT

COLD DRY AIRMASS IN PLACE WILL HAVE IDEAL RADIATIONAL CONDITIONS FOR
A TEMPERATURE CRASH SATURDAY NIGHT...AND THE PROGRESSIVELY COLDER
MODEL TREND NOW SPORTS LOW LEVEL THICKNESSES BELOW 1280 METERS.
LOCAL STUDIES SUGGEST THAT WE NEED ANOTHER MINOR TWEAK DOWNWARD INTO
THE LOWER 20S ACROSS THE NORTH TO MID 20S ACROSS THE SOUTH.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 210 PM FRIDAY...

TO BEGIN THE PERIOD...HIGH PRESSURE WILL QUICKLY MIGRATE OVER THE
AREA...BECOMING SITUATED OFF THE SOUTHEAST COAST BY SUNDAY
AFTERNOON/EVENING. AS A RESULT...TEMPS WILL BEGIN TO MODERATE SOME
AS RETURN FLOW BEGINS TO SET UP OVER THE REGION...WITH GENERALLY MID
50S EXPECTED. OVERNIGHT...CLOUDS WILL INCREASE THROUGH THE OVERNIGHT
HOURS AS ANOTHER SHORT WAVE/ASSOCIATED COLD FRONT APPROACHES THE
AREA. THIS (ALONG WITH SOME WARM AIR ADVECTION) WILL KEEP TEMPS IN
THE MID/UPPER 30S.

AS THE AFOREMENTIONED FRONT CROSSES THE AREA ON MONDAY...PRECIP
CHANCES WILL INCREASE. ALTHOUGH WITH VERY LIMITED MOISTURE RETURN
EXPECTED...WILL NOT GO ANY HIGHER THEN LOW END CHANCE POP. DESPITE
THE FRONTAL PASSAGE AND ITS ASSOCIATED CLOUDS AND LIGHT PRECIP...
TEMPS WILL WARM EVEN MORE ON MONDAY (OVER SUNDAY) GIVEN THE WESTERLY
DOWNSLOPE FLOW. HIGHS SHOULD RISE INTO THE 60S. EVEN MORE
MODIFICATION WILL OCCUR INTO MID WEEK GIVEN MORE IN THE WAY OF
SUNSHINE. HIGHS ON TUESDAY WILL BE MOSTLY IN THE UPPER 60S (MAYBE
APPROACHING 70 DEGREES ACROSS THE SOUTH)...WITH MOSTLY LOWER 70S
EXPECTED BY WEDNESDAY.

OUR NEXT SOUTHERN STREAM SYSTEM IS PROGGED TO APPROACH THE AREA BY
THE LATTER HALF OF THE WEEK. AS CAN BE EXPECTED THIS FAR OUT IN THE
FORECAST PERIOD...CONFIDENCE IN THE EXACT DETAILS IS NOT HIGH. FOR
NOW...WILL INTRODUCE POPS BACK INTO THE FORECAST BY THURSDAY...WITH
PRECIP LINGERING INTO FRIDAY. TEMPS ARE EXPECTED TO REMAIN SLIGHTLY
ABOVE NORMAL.

&&

.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 132 PM FRIDAY...

24-HR TAF PERIOD: BACK-EDGE OF ANA-FRONTAL SHOWERS AND ASSOCIATED
MVFR/IFR CEILINGS WILL CONTINUE TO PUSH EAST THROUGH THE
AFTERNOON/EARLY EVENING.

CEILINGS HAVE IMPROVED TO VFR OUT WEST WHERE THE PRECIP HAS LARGELY
TAPERED OFF...AND HAVE CARRIED THIS TREND EASTWARD LATE THIS
AFTERNOON AND EVENING. HOWEVER...SCATTERED SHOWERS ACCOMPANYING THE
VIGOROUS UPPER TROUGH THROUGH THE AREA COULD BRING A BRIEF PERIOD OF
MVFR/IFR CONDITIONS BETWEEN 00Z TO 09Z. CONDITIONS WILL RETURN TO
VFR FROM WEST-EAST IN THE WAKE OF THE UPPER TROUGH PASSAGE BETWEEN
06-12Z SAT MORNING.

LOOKING AHEAD: VFR CONDITIONS WILL RULE OVER THE WEEKEND AS HIGH
PRESSURE BUILDS INTO THE REGION FROM THE WEST/NW. THE NEXT POTENTIAL
FOR ADVERSE CONDITIONS WILL BE ASSOC/W AN UPPER LEVEL DISTURBANCE
MONDAY AFTERNOON...WITH VFR CONDITIONS EXPECTED THEREAFTER.

&&

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

&&

$$

SYNOPSIS...CBL/VINCENT
NEAR TERM...CBL/VINCENT
SHORT TERM...VINCENT/MLM
LONG TERM...KRD
AVIATION...CBL/VINCENT



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