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/...
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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.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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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.
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&& .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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