Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | 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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
338 FXUS62 KRAH 040822 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 322 AM EST THU FEB 04 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 /TODAY THROUGH TONIGHT/... AS OF 300 AM THURSDAY... TODAY: MORE WET WEATHER TODAY... ESPECIALLY EAST/SOUTH OF THE TRIAD. THE COLD FRONT IS CURRENTLY SITTING JUST NW OF THE CWA... AND IS EXPECTED TO MOVE VERY SLOWLY EASTWARD THROUGH THE FORECAST AREA TODAY... REACHING COASTAL SECTIONS BY SUNDOWN. BUT THE FRONTAL ZONE JUST ALOFT WILL LAG THIS FRONT BY SEVERAL HOURS WITH SOUTHWESTERLY MID LEVEL FLOW STILL ROUGHLY PARALLEL TO THE SURFACE FRONT... HINDERING ITS EASTWARD MOVEMENT. THE STRENGTHENING UPPER LEVEL JET FROM NE TN UP THROUGH THE CENTRAL APPALACHIANS TO THE CANADIAN MARITIME WILL INDUCE A BATCH OF ENHANCED UPPER DIVERGENCE WHICH WILL TRACK NORTHEASTWARD THROUGH CENTRAL/ERN NC FROM MID MORNING THROUGH THE AFTERNOON... RESULTING IN A RESURGENCE OF WIDESPREAD RAINFALL BACK TOWARD THE WNW... AS PW VALUES REMAIN WELL ABOVE NORMAL... IN THE 1.0-1.5 INCH RANGE. SO... AFTER A RELATIVE BREAK IN STEADY RAINFALL EARLY THIS MORNING (LOWER CHANCES MAINLY SE HALF)... WILL TREND POPS BACK UP TO LIKELY TO CATEGORICAL OVER THE SE TWO-THIRDS THIS MORNING... WITH LOWER CHANCES NW... LASTING THROUGH THE AFTERNOON. THE 850 MB TROUGH FINALLY SHIFTS EASTWARD THROUGH CENTRAL/ERN NC TONIGHT WITH ENSUING DRYING DOWNSLOPE FLOW FROM THE NW... AND THE INTENSE UPPER DIVERGENCE DIMINISHES FROM SW TO NE AS THE RIGHT ENTRANCE REGION SHIFTS TO OUR ENE. WILL TREND POPS DOWN GRADUALLY FROM WSW TO ENE LATE TONIGHT... ALTHOUGH THE FAR ERN COASTAL PLAIN WILL STILL HAVE LIKELY TO CATEGORICAL POPS THROUGH THE LATE NIGHT AS UPPER LEVEL ROOTED FORCING FOR ASCENT REMAINS STRONG THERE. ADDITIONAL RAINFALL TODAY THROUGH TONIGHT IS EXPECTED TO RANGE FROM A TENTH TO A HALF INCH WEST OF HIGHWAY 1... WHILE ALONG AND EAST OF HIGHWAY 1... WE SHOULD SEE AN ADDITIONAL 0.75-1.75 INCHES OF RAIN. THIS ADDED RAINFALL IN THE EAST IS UNLIKELY TO BE PARTICULARLY HEAVY... REMAINING LIGHT TO MODERATE... AND WILL FALL OVER A LONG ENOUGH DURATION TO LIMIT WIDESPREAD FLOODING CONCERNS... PARTICULARLY CONSIDERING THE SANDY NATURE OF THE SOIL IN THE COASTAL PLAIN. HOWEVER... RISING RIVERS AND SWOLLEN CREEKS ALONG WITH NUISANCE STREET FLOODING AND HIGH WATER IN POOR DRAINAGE AREAS ARE ALL A NEAR CERTAINTY... AND WILL ADDRESS THIS CONCERN IN THE HAZARDOUS WEATHER OUTLOOK. TEMPS WILL FALL FOR MUCH OF THE DAY AS THE COOLER LOW LEVEL AIR EASES IN... SO THE CURRENTLY READINGS ARE LIKELY TO BE THE CALENDAR DAY HIGHS. EXPECT TEMPS TO FALL THROUGH THE 50S TODAY... AND INTO THE 40S NW TO SE LATE AFTERNOON THROUGH TONIGHT... BOTTOMING OUT IN THE 33-39 RANGE. 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 && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... AS OF 310 PM 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 WEDNESDAY/... 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 /06Z THURSDAY THROUGH MONDAY/... AS OF 115 AM THURSDAY... POOR AVIATION CONDITIONS -- MOSTLY IFR -- WILL DOMINATE AT ALL SITES THIS MORNING... ALTHOUGH IMPROVEMENT TO MVFR THEN VFR IS EXPECTED AT INT/GSO TOWARD DAYBREAK. RDU/RWI/FAY ARE EXPECTED TO REMAIN IFR OR PERHAPS LOW-END MVFR THROUGH MUCH OF THE NEXT 24 HRS. A COLD FRONT CURRENTLY OVER THE NC FOOTHILLS WILL TRACK SLOWLY EASTWARD TODAY... REACHING COASTAL NC TONIGHT. DEEP MOISTURE CONTINUES TO STREAM NORTH-NORTHEASTWARD ALONG THE FRONT... RESULTING IN MULTIPLE CLOUD DECKS OVER OUR AREA THAT WILL PERSIST THROUGH TONIGHT. IFR/LIFR CIGS AT INT/GSO ARE EXPECTED TO IMPROVE TO MVFR THEN VFR IN THE 11Z-14Z TIME FRAME AND REMAIN VFR THIS AFTERNOON THROUGH TONIGHT. FURTHER EAST HOWEVER... CIGS ARE EXPECTED TO HOLD IN THE 500-1500 FT AGL RANGE THROUGH THE TAF VALID PERIOD... WITH PERIODS OF RAIN REDUCING VSBYS TO MVFR OR IFR ESPECIALLY FROM MID MORNING THROUGH THE AFTERNOON (MAINLY 15Z-22Z) AS A WEAK TROUGH ALOFT CROSSES THE REGION. SURFACE WINDS INITIALLY LIGHT FROM THE SW WILL SWING AROUND TO NW THEN FROM THE NORTH OR NNE... FIRST AT INT/GSO EARLY THIS MORNING THEN TO RDU BY MID MORNING AND TO RWI/FAY BY LATE MORNING. SOME GUSTY WINDS FROM THE NNE UP TO 20 KTS ARE POSSIBLE THIS AFTERNOON INTO TONIGHT. LOOKING BEYOND 06Z EARLY FRI MORNING... SUB-VFR CONDITIONS (MOSTLY IFR CIGS AND MVFR VSBYS) WILL HOLD UNTIL NEAR OR SOON AFTER DAYBREAK FRI... WHEN A STRONG UPPER LEVEL DISTURBANCE MOVES OVER AND EXITS THE AREA. THEN... 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. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...HARTFIELD LONG TERM...ELLIS AVIATION...HARTFIELD

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