Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 041749 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1249 PM EST THU FEB 4 2016 .SYNOPSIS... A COLD FRONT CURRENTLY OVER CENTRAL NORTH CAROLINA WILL SHIFT SLOWLY EAST TO THE CAROLINA COAST TODAY AND TONIGHT... AS WAVES OF LOW PRESSURE TRACK NORTHWARD ALONG THE FRONT. THIS FRONT WILL PUSH OFFSHORE EARLY FRIDAY MORNING... THEN COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY INTO THE WEEKEND. AN ARCTIC COLD FRONT WILL ARRIVE EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 1030 AM THURSDAY... DEEP AND ANOMALOUSLY MOIST SOUTHWESTERLY FLOW CONTINUES ACROSS THE SOUTHEAST US...DOWNSTREAM OF A DEEP UPPER TROUGH THAT WILL SWING EAST ACROSS THE REGION TONIGHT. A COLD FRONT SNAKES FROM CENTRAL GA UP THROUGH UPSTATE SC AND THEN BENDS NORTHEAST THROUGH THE NORTHWEST PIEDMONT THIS MORNING. THE HIGHEST PW AXIS IS JUST EAST OF OUR AREA...FOCUSED MAINLY ALONG THE COAST WHERE PW IS 1.4-1.8". PERTURBATIONS WITHIN THE SOUTHWEST FLOW WILL PERIODICALLY ENHANCE PRECIP OVER THE COASTAL PLAIN...PARTICULARLY WITH A COUPLE NOTABLE WAVES TO IMPACT EASTERN NC THROUGH THIS AFTERNOON AND THEN AGAIN CLOSER TO MIDNIGHT...THE LATTER MORE ASSOCIATED WITH THE UPPER TROUGH AND A COASTAL LOW THAT WILL DEVELOP IN RESPONSE. SO FAR...MODELS HAVE OVERFORECAST QPF...WITH JUST A COUPLE TENTHS OF AN INCH GENERALLY REPORT SINCE MIDNIGHT. RE[PORTS UPSTREAM IN EAST-CENTRAL SC ARE ALSO UNDERWHELMING COMPARED TO MODEL FORECASTS...WITH JUST A QUARTER INCH OF LESS OR LESS. THERE WILL NO DOUBT BE AN UPTICK IN RAIN RATES AS THE AFOREMENTIONED UPPER DISTURBANCE PASSES AND LOW-LEVEL CONVERGENCE INCREASES WITH THE FRONT OOZES EAST THROUGH THE PIEDMONT....BUT THE HEAVIEST AND FLOOD THREATENING RAINFALL LOOKS LIKE IT WILL BE CONFINED TO THE COAST. A HALF INCH TO AN INCH OF RAINFALL THROUGH THIS AFTERNOON MAY CAUSE SOME LOCALIZED FLOODING AND OVERFLOWING OF SMALL STREAMS...WHICH CAN BE HANDLED WITH FLOOD ADVISORIES IF NEEDED. OTHERWISE...AREA WEST OF HIGHWAY 1 WILL SEE LITTLE IN THE WAY OF PRECIP. PARTIAL BREAKS IN CLOUDS OVER THE WESTERN PIEDMONT WILL ALLOW TEMPS TO RISE A LITTLE INTO THE MID 50S...BUT COLD ADVECTION WILL KICK IN THIS AFTERNOON AND VALUES WILL BEGIN TO FALL INTO THE 40S. -SMITH TEMPS WILL BOTTOM OUT IN THE 33-39 RANGE TONIGHT. THE COLDER AIR TONIGHT WILL GENERALLY BE CHASING THE MOISTURE... WITH DRYING TAKING PLACE ALOFT LATE... BUT A FEW INCONSEQUENTIAL WET FLAKES MAY OCCUR LATE TONIGHT IN THE NE CWA AS THE PRECIP EXITS. -GIH
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&& .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... AS OF 310 AM THURSDAY... PATCHY LIGHT RAIN SHOULD BE LINGERING OVER THE NE CWA EARLY FRI MORNING AS A POWERFUL MID LEVEL SHORTWAVE SHIFTS ENE THROUGH THE REGION. BUT ANY RESIDUAL RAIN WILL END BY MID MORNING AS PW VALUES DROP WITH THE DEPARTURE OF THE SHORTWAVE TROUGH AND UPPER DIVERGENCE. THICKNESSES PLUNGE INTO THE 1280S WITH THE ARRIVAL OF THE COLDER AIR MASS... A POLAR-SOURCE AND MINIMALLY MODIFIED HIGH PRESSURE RIDGE MOVING IN FROM THE WEST. WITH STRONGLY SINKING AND DEEPLY DRY AIR... EXPECT MOSTLY CLEAR SKIES WITH JUST PATCHY FLAT CU BENEATH THE PROMINENT SUBSIDENCE INVERSION ALOFT. HIGHS FRI 46-51 AND LOWS IN THE MID-UPPER 30S WITH DIMINISHING WINDS FRI NIGHT. -GIH && .LONG TERM /SATURDAY THROUGH THURSDAY/... AS OF 320 AM THURSDAY... SATURDAY AND SUNDAY: A VERY DEEP LONGWAVE TROUGH WILL DIG DOWN THE MISSISSIPPI VALLEY ON SATURDAY AS SURFACE HIGH PRESSURE RESIDES OVER THE CAROLINAS...KEEPING TEMPERATURES NEAR OR JUST BELOW NORMAL WITH HIGHS IN THE LOW 50S AND LOWS SATURDAY NIGHT IN THE LOW 30S. SKIES SHOULD REMAIN PARTLY CLOUDY WITH INCREASING CLOUDS LATE IN THE DAY ON SATURDAY AS A FEW SHORTWAVES FORM OFF OF THE COAST IN THE PRECURSOR TO A STRONG LOW PRESSURE SYSTEM THAT WILL FORM OFF OF THE FLORIDA AND GEORGIA COAST. THE LATEST RUNS OF THE GFS AND ECMWF ARE IN BETTER AGREEMENT AND BOTH HAVE THE LOW REMAINING OFFSHORE WITH PRECIPITATION ONLY AFFECTING COASTAL AREAS. IN FACT...THE LATEST RUN OF THE GFS IS NOW EAST OF THE ECMWF. IT APPEARS THAT THE UPPER LEVEL LOW DEVELOPING TO ITS IMMEDIATE WEST IS WEAKER IN THIS SIMULATION AND IT DOES NOT DRAW PRECIPITATION BACK TO THE WEST LIKE IT WAS DOING 24 HOURS AGO. THEREFORE DONT EXPECT MUCH PRECIP THIS WEEKEND...AND THUS NO P-TYPE ISSUES EITHER. WILL LEAVE SLIGHT CHANCES IN THE EAST THROUGH SUNDAY AFTERNOON TO ACCOUNT FOR POTENTIAL MODEL ERROR. MONDAY THROUGH WEDNESDAY: AFTER THE LOW MOVES UP THE EAST COAST A SECOND EXTREMELY DEEP UPPER TROUGH AIDED BY ANOTHER CUTOFF LOW WILL BRING A SHOT OF ARCTIC AIR TO THE OHIO VALLEY AND THE MAJORITY OF THE EASTERN SEABOARD. AS THE SURFACE FRONT COMES IN LATE ON MONDAY AFTERNOON...MODELS DO PRODUCE SOME LIGHT PRECIPITATION...PROBABLY IN THE FORM OF RAIN INITIALLY BUT AFTER 00Z THICKNESSES PLUNGE INTO THE SNOW REGION OF THE NOMOGRAM WITH NO SIGNS OF COMING BACK ANYTIME SOON. MODEL QPF IS VERY LIGHT AFTER THAT POINT AND IT IS UNCERTAIN IF WE WILL SEE PRECIPITATION OR NOT BUT WITH THICKNESS VALUES APPROACHING RECORD LOW VALUES...ANYTHING THAT DOES FALL WILL MOST LIKELY EITHER SUBLIMATE OR FALL IN THE FORM OF SNOW FLURRIES OR SHOWERS. MODELS SHOW LIGHT QPF ON AND OFF THROUGH WEDNESDAY. WHILE PERIODS OF SNOW COULD BE POSSIBLE...ACCUMULATIONS WOULD MOST LIKELY BE VERY MINIMAL GIVEN THE LOW QPF VALUES. WHILE THE PRECIPITATION FORECAST FOR THIS PERIOD IS UNCERTAIN...THE TEMPERATURE FORECAST HAS A LOT MORE CONFIDENCE. IT WILL BE COLD. MODELS ARE IN DISAGREEMENT ABOUT HOW LOW IT WILL GO BUT A CONSERVATIVE BET WOULD BE HIGHS IN THE MID 30S TO NEAR 40 DEGREES BY WEDNESDAY AFTERNOON AND LOWS IN THE MID 20S WITH THE POTENTIAL OF SEEING SOME TEENS WEDNESDAY NIGHT INTO THURSDAY MORNING. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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AS OF 1245 PM THURSDAY... POO AVIATION CONDITIONS...MAINLY OVER EASTERN NC...WILL CONTINUE THIS AFTERNOON AND EVENING AS A PLUME OF MOISTURE STREAMS ALONG THE SOUTHEAST COAST. A COLD FRONT HAS ALREADY MOVED THROUGH KGSO AND KINT...WITH WINDS SWINGING AROUND TO NORTH-NORTHEASTERLY...AND THE SAME WILL OCCUR AT KRDU/KFAY/KRWI THIS AFTERNOON AS THE FRONT MOVES TOWARD THE COAST. WITH MVFR AND IFR CONDITIONS PREDOMINATE AT KRWI AND KFAY...PERIODS OF RAIN MAY BE MODERATE TO HEAVY AT TIMES THIS AFTERNOON AND THEN AGAIN OVERNIGHT...AND MAY RESULT IN LIFR CONDITIONS. MVFR CONDITIONS WILL BE MORE COMMON AT KRDU THIS AFTERNOON...WHILE KINT AND KGSO EXPERIENCE VFR OR TEMPORARILY MVFR CONDITIONS. A STRONG UPPER TROUGH WILL SWING ACROSS THE AREA TONIGHT...WHILE A LOW PRESSURE DEEPENS OFF THE CAROLINA COAST. THIS WILL LEAD TO NORTHERLY WINDS INCREASING TO 10-14KT AND POSSIBLY GUSTING TO 20-25KT...WITH A PERIOD OF RAIN MIXING OR CHANGING TO ALL SNOWPOSSIBLEAFTER 06Z...MAINLY FROM KGSO EAST TO KRDU/KRWI AND NORTH..BEFORE DRY AIR ALOFT QUICKLY RUSHES IN AND BRING VFR CONDITIONS FOR FRIDAY. LOOKING BEYOND 18Z FRIDAY MORNING...VFR CONDITIONS WILL DOMINATE INTO EARLY NEXT WEEK AS CHILLY HIGH PRESSURE BUILDS IN FROM THE WEST FRIDAY THROUGH MONDAY... ALTHOUGH ANOTHER STRONG UPPER LEVEL DISTURBANCE MAY BRING A CHANCE OF SUB-VFR CONDITIONS LATE IN THE PERIOD... MAINLY SUNDAY INTO EARLY MONDAY.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...SMITH/HARTFIELD SHORT TERM...HARTFIELD LONG TERM...RE AVIATION...HARTFIELD/SMITH

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