Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 250602 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 202 AM EDT MON APR 25 2016 .SYNOPSIS...
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SOUTHERLY RETURN FLOW WILL RESULT IN A WARMING TREND THROUGH MID- WEEK.
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&& .NEAR TERM /THROUGH MONDAY NIGHT/...
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AS OF 930 PM SUNDAY... WITH BUILDING HEIGHTS ALOFT AND HIGH PRESSURE ALONG THE COAST... SKIES ARE CLEAR AND WINDS ARE LIGHT OR CALM OVER CENTRAL NC. GUIDANCE SUGGESTS SOME STRATOCU OVER THE SOUTHERN/WESTERN PIEDMONT LATE TONIGHT...COURTESY OF LINGERING MOISTURE OVER EASTERN SC THAT IS LIKELY TRAPPED BELOW THE RELATIVELY WEAK OBSERVED SUBSIDENCE INVERSION..THOUGH THE 00Z/25 KCHS RAOB DOESN`T REALLY CAPTURE WHAT MAY BE LEFT OVER FROM THAT DIMINISHING CU FIELD. THAT BEING SAID...THE ALLEGED MOISTURE SHOULD DRIFT INTO UPSTATE SC AND AND SW NC AND MAY RESULT IN PARTLY CLOUDY SKIES BY DAYBREAK. OTHERWISE EASTERN NC SHOULD BE COOLER TONIGHT GIVEN THE PROXIMITY TO THE SURFACE RIDGE...WITH LOWS RANGING FROM THE UPPER 40S NE TO LOWER 50S SE. -22 MON/MON NIGHT: MID LEVEL LOW PRESSURE DIGGING FROM NV TOWARD THE FOUR CORNERS REGION WILL CONTINUE TO BUILD RIDGING ALOFT DOWNSTREAM OVER THE GULF STATES AND MID SOUTH... ITS EASTWARD PROGRESS BEING HINDERED SOMEWHAT BY A LARGE POLAR LOW OVER SE CANADA. THE SURFACE HIGH CONTINUES TO SLIDE OFFSHORE WITH SSW LOW LEVEL FLOW PICKING UP... DRAWING WARMER AIR INTO THE FORECAST AREA. THICKNESSES START OUT SLIGHTLY ABOVE NORMAL BUT RISE STEADILY THROUGH THE DAY... FAVORING MILD HIGHS AROUND 80... WITH FLAT MOSTLY SCATTERED CUMULUS... LIKELY GREATER COVERAGE OVER THE PIEDMONT NEAR A WEAK LEE TROUGH. WARM MON NIGHT WITH LIGHT SW WINDS AND FAIR SKIES. LOWS IN THE UPPER 50S TO AROUND 60. -GIH
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 320 PM SUNDAY... LOTS OF UNCERTAINTY IN THE SHORT AND LONG TERM PORTIONS OF THE FORECAST WITH MUCH OF THE QUESTION EARLY ON SURROUNDING A FRONTAL SYSTEM THAT IS PROGGED TO DROP DOWN FROM THE NORTH INTO NC. MODELS ARE HAVING A HARD TIME FIGURING OUT JUST HOW FAR SOUTH THE FRONT WILL MAKE IT AND MOST SOLUTIONS HAVE IT STALLING OUT SOMEWHERE OVER THE STATE...WHICH MAKES THE FORECAST FOR CENTRAL NC VERY LOW CONFIDENCE AT THIS TIME. LOOKS LIKE MOST OF THE AREA WILL BE DRY AND WARM ON TUESDAY AS THE FRONT HANGS OUT TO THE NORTH...BUT VA BORDER COUNTIES COULD SEE A SOME SHOWER ACTIVITY LATE IN THE EVENING. TEMPERATURES SHOULD REACH THE MID 80S AS MUCH OF THE FORECAST AREA WILL BE IN THE WARM SECTOR WITH SOUTHWESTERLY RETURN FLOW AT THE SURFACE. SLIGHT CHANCES WILL REMAIN ACROSS THE NORTH OVERNIGHT TUESDAY NIGHT INTO WEDNESDAY BUT ACTIVITY SHOULD REMAIN AT A MINIMUM EXCEPT POSSIBLY ACROSS THE NORTH. LOWS IN THE LOWER 60S. ON WEDNESDAY AFTERNOON THE FRONT WILL SINK FURTHER SOUTH AND RAIN CHANCES WILL INCREASE ACROSS THE AREA. AGAIN...HOW FAR SOUTH THE FRONT MAKES IT WILL DETERMINE THE EXTENT OF ACTIVITY ACROSS THE SOUTH. BY AFTERNOON...INSTABILITY WILL INCREASE...PARTICULARLY ACROSS THE SOUTHWEST...WHERE THUNDER WILL BE MORE OF A THREAT THEN POINTS NORTH AND EAST. HIGHS SHOULD BE DOWN TO THE LOW 80S ACROSS THE NORTH BUT STILL IN THE MID 80S ACROSS THE SOUTH. SHOWER ACTIVITY SHOULD CONTINUE INTO WEDNESDAY NIGHT WITH LOWS AGAIN NEAR 60 DEGREES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 320 PM SUNDAY... CONTINUED RAIN CHANCES WELL INTO THE LONG TERM AS CENTRAL NC GETS SQUEEZED BETWEEN THE RETREATING COLD FRONT TO THE NORTH (NOW A WARM FRONT) AND A SECOND COLD FRONT FROM THE WEST...BOTH STEMMING FROM A LOW PRESSURE SYSTEM MOVING EAST FROM THE CENTRAL PLAINS TOWARDS THE OHIO VALLEY. THE SYSTEM IS NOT VERY ORGANIZED AT ALL...ZONAL FLOW ALOFT...SO IT IS HARD TO TELL EXACTLY HOW PRECIPITATION WILL PLAY OUT...BUT THE PATTERN SUGGESTS THAT PRECIPITATION CHANCES WILL REMAIN OVER THE AREA UNTIL THE LOW EXITS THE EAST COAST ON FRIDAY. SINCE THE COOL AIR TO THE NORTH NEVER REALLY MAKES IT INTO NC...HIGH TEMPERATURES THURSDAY AND FRIDAY WILL REMAIN IN THE 80S WITH LOWS STILL IN THE 60S. SATURDAY AND SATURDAY NIGHT SHOULD BE FAIRLY QUIET BEHIND THE FRONT AND THIS LOOKS LIKE THE DRIEST DAY OF THE LONG TERM. WITH HIGH PRESSURE EDGING DOWN FROM THE NORTH...TEMPERATURES WILL BE A FEW DEGREES COOLER...UPPER 70S TO NEAR 80 DEGREES. LOWS SATURDAY NIGHT IN THE MID TO UPPER 50S. FOR SUNDAY...MODELS ARE TRACKING A LOW PRESSURE SYSTEM OVER THE CENTRAL PART OF THE COUNTRY THAT IS MUCH MORE ORGANIZED AND HAS AN UPPER TROUGH/CLOSED LOW ASSOCIATED WITH IT. THIS WILL HELP TO PUSH IT ACROSS THE COUNTRY FASTER THAN THE LAST SYSTEM. WHILE TIMING IS UNCERTAIN WITH THIS SYSTEM...CENTRAL NC COULD SEE AN UPTICK IN WARM SECTOR PRECIPITATION AHEAD OF THE SYSTEM AS MOISTURE TRANSPORT INCREASES...PARTICULARLY ACROSS THE WEST. HIGHS IN THE MID 70S TO NEAR 80 DEGREES. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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AS OF 200 AM MONDAY... 24-HOUR TAF PERIOD: VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD...HOWEVER...HAZARDOUS AVIATION CONDITIONS IN THE FORM OF STRONG (35-40 KT) LOW-LEVEL WIND SHEAR (400-800 FT AGL) WILL BE PRESENT AT ALL TERMINALS UNTIL ~12Z THIS MORNING...ABRUPTLY ENDING SHORTLY AFTER THE ONSET OF DIURNAL HEATING /MIXING/. THIS PARTICULAR PATTERN...I.E. THE ONSET OF SOUTHERLY RETURN FLOW AS HIGH PRESSURE MOVES OFFSHORE...IS ESPECIALLY HAZARDOUS BECAUSE IT OFTEN OCCURS WHEN CONDITIONS ARE OTHERWISE VFR/BENIGN...BECAUSE THE GREATEST SHEAR IS LOCATED CLOSER TO THE GROUND (ATOP THE NOCTURNAL INVERSION)...AND BECAUSE MODEL GUIDANCE IS NOTORIOUS IN UNDER- REPRESENTING THE STRENGTH OF THE LOW-LEVEL JET (COMPARE GFS/NAM/RAP FCST SOUNDINGS WITH KRAX VELOCITY DATA THIS MORNING). OTHERWISE... EXPECT SCATTERED VFR CEILINGS AT 4000-5000 FT AGL THIS AFTERNOON AND SSW/SW WINDS AT 10-15 KT AFTER SUNRISE...PERHAPS GUSTING TO ~20 KT AS THE NOCTURNAL INVERSION MIXES OUT THIS MORNING AND AGAIN LATER THIS AFTERNOON AS THE MSLP GRADIENT TIGHTENS FROM THE WEST. LOOKING AHEAD: VFR CONDITIONS WILL PREVAIL UNTIL MID-WEEK WHEN A WEAKENING COLD FRONT IS PROGGED TO STALL OVER THE REGION...IN THE PRESENCE OF INCREASING MOISTURE VIA PERSISTENT SOUTHERLY RETURN FLOW. SUB-VFR CONDITIONS ASSOC/W CONVECTION WILL BE POSSIBLE AT ALL TERMINALS MID/LATE WEEK...WITH PRE-DAWN FOG/STRATUS POSSIBLE AS WELL...ESP. IN AREAS AFFECTED BY AFT/EVE CONVECTION. -VINCENT
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...HARTFIELD/22 SHORT TERM...ELLIS LONG TERM...ELLIS AVIATION...VINCENT

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