Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 240542 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1242 AM EST SAT JAN 24 2015 .SYNOPSIS...AN AREA OF LOW PRESSURE WILL TRACK NORTHEAST THROUGH EASTERN NC OVERNIGHT...AND THEN UP THE MID-ATLANTIC SEABOARD ON SATURDAY. HIGH PRESSURE WILL BUILD BRIEFLY INTO THE AREA ON SUNDAY...IN ADVANCE OF A CLIPPER LOW PRESSURE SYSTEM MOVING THROUGH THE REGION SUNDAY NIGHT AND INTO MONDAY. &&24 HOUR TAF PERIOD: HEAVIEST PRECIPITATION THIS MORNING REMAINING SOUTH AND EAST OF THE AREA. WE WILL BE ENTERING A LULL IN THE PRECIPITATION FOR THE NEXT SEVERAL HOURS WHERE DRIZZLE OR VERY LIGHT RAIN WILL BE THE PREDOMINANT MODE OF PRECIPITATION. HIGH RESOLUTION MODELS SHOW SOME PRECIPITATION FILLING BACK IN AFTER 9Z FROM RALEIGH EASTWARD TO THE COAST WITH DRIZZLE TO LIGHT RAIN STILL POSSIBLE IN THE WEST. MODELS HOLD ON TO PRECIPITATION THROUGH 18Z ALTHOUGH IT MAY PULL OUT TO THE NORTHEAST EARLIER THAN THAT. ONCE IT MOVES OUT. THE REMAINDER OF THE TAF PERIOD IS EXPECTED TO BE DRY. CEILINGS WILL MOST LIKELY REMAIN IFR/LIFR THROUGH MID MORNING OR SO BEFORE STEADILY IMPROVING BACK TO VFR. SKIES WILL EVENTUALLY CLEAR BY LATE AFTERNOON. VISIBILITIES MEANWHILE SHOULD REMAIN IN THE IFR/MVFR RANGES THROUGH A SIMILAR TIME PERIOD BEFORE RETURNING TO VFR. WITH PRECIPITATION AND WINDS STAYING UP A LITTLE OVERNIGHT...DO NOT EXPECT MUCH OF A DENSE FOG THREAT. WINDS WILL VARY FROM CALM TO 10 KTS THROUGH THE MORNING WITH SOME VARYING DIRECTION AS WELL BUT WITH SOME NORTHERLY COMPONENT. BY AFTERNOON WINDS WILL BACK AROUND TO WESTERLY WITH SUSTAINED WINDS NEAR 10 KTS GUSTING TO 20 KTS. GUSTS WILL SUBSIDE AFTER SUNSET WITH WINDS OUT OF THE WEST AT 5-10 KTS. LONG TERM: MAINLY VFR CONDITIONS FOR THE LONG TERM AFTER THE CURRENT SYSTEM MOVES OFF. THE EXCEPTION TO THIS COULD BE WITH A CLIPPER SYSTEM ON MONDAY THROUGH MONDAY NIGHT WHICH COULD PRESENT A FEW PERIODS OF SUB VFR CONDITIONS. .NEAR TERM /THROUGH TONIGHT/... AS OF 948 PM FRIDAY... OVER THE PAST FEW HOURS...A LARGE HOLE HAS DEVELOPED ALONG THE WESTERN EDGE OF THE PRECIP SHIELD...LIKELY A PRODUCT OF THE DEEP CONVECTION THAT SWEPT EAST ACROSS THE NORTHEAST EARLIER THIS AFTERNOON/EVENING THAT PER LATEST WV IMAGERY HAS SHUNTED THE DEEP MOIST PLUME EASTWARD...PRIMARILY OFFSHORE. SIGNIFICANT CONCERNS HAVE ARISEN AS TO WHETHER OR NOT PRECIP WILL FILL BACK OVERNIGHT AS THE AREA OF LOW PRESSURE OVER THE SE US TRACK NEWD ACROSS EASTERN NC BETWEEN 06 TO 12Z. MODEL GUIDANCE IS NOT HANDLING CURRENT RADAR TRENDS WELL AT ALL...BUT ITS STARTING TO LOOK LIKE QPF AMOUNTS WILL BE SIGNIFICANTLY LESS THAN EARLIER ANTICIPATED...WITH THE MODERATE AND HEAVY RAINFALL REMAINING SOUTH AND EAST OF THE AREA. WHILE INFLUX OF ATLANTIC MOISTURE AHEAD AND ALONG THE LOW PRESSURE TRACK COULD RESULT IN A SLIGHT UPTICK IN INTENSITY ACROSS THE FAR SE ZONES...INLAND/PIEDMONT AREAS WILL LIKELY SEE INTERMITTENT LIGHT RAIN AND DRIZZLE FOR THE REMAINDER OF THE NIGHT. HAVE REDUCED QPF BY HALF...WITH STORM TOTAL QPF 0.50 TO 1.0" EXPECTED ACROSS THE AREA. TEMPERATURES OVERNIGHT WILL HOLD NEARLY STEADY IN THE MID TO UPPER 30S ACROSS THE PIEDMONT...WELL WITHIN THE CAD AIRMASS. A LITTLE DIFFERENT STORY ACROSS THE SOUTHERN COASTAL PLAIN ZONES WHERE TEMPS WILL WARM INTO THE 50S THROUGH 09Z WITH THE APPROACH OF THE LOW AND ASSOCIATED SOUTHERLY FLOW...THEN DROP BACK DOWN INTO THE 40S IN THE WAKE OF THE LOW LIFTING OFF TO THE NORTH AS WINDS BECOMING NORTHERLY. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... AS OF 230 PM FRIDAY... THE MAIN RAIN EVENT WILL END BETWEEN 09Z/15Z SW TO NE ACROSS OUR REGION SATURDAY AS THE STORM BOMBS AS IT MOVES AWAY FROM DELMARVA. THE TRAILING DEFORMATION BAND OF PRECIPITATION WITH THE MID LEVEL LOW IS EXPECTED TO WEAKEN AND DISSIPATE AS IT SPREADS EAST FROM KY/TN/WVA INTO WESTERN VA AND NORTH-CENTRAL NC SATURDAY. IN ADDITION... THE BOUNDARY LAYER WINDS WILL SHIFT TO THE WNW AND INCREASE TO 10-20 MPH IN DOWNSLOPE FASHION DURING THE AFTERNOON. THIS SHOULD LEAD TO SHARP CLEARING FROM OFF THE BLUE RIDGE INTO THE PIEDMONT DURING THE AFTERNOON. SKIES SHOULD BECOME PARTLY SUNNY DOWN EAST LATE IN THE AFTERNOON. HIGHS SHOULD RETURN INTO THE 45-55 RANGE NW TO SE. THE SKIES SHOULD REMAIN MOSTLY CLEAR TO PARTLY CLOUDY SATURDAY NIGHT. LOWS 30-35 WITH DIMINISHING NW BREEZES IN THE EVENING. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 235 PM FRIDAY... SUNDAY: FAIR WEATHER EXPECTED DURING THE DAYTIME HOURS SUNDAY WITH A FLAT RIDGE OVER OUR AREA...BETWEEN SATURDAY`S DEPARTING SHORT WAVE...AND THE NEXT SHORT WAVE THAT WILL BE DROPPING SE ACROSS THE OH VALLEY. FORECAST SOUNDINGS SUGGEST NEAR-NORMAL HIGHS IN THE LOWER TO MID 50S. SUNDAY NIGHT...THE AFOREMENTIONED SHORT WAVE WILL CROSS THE MOUNTAINS WHILE THE ASSOC SFC LOW MOVES FROM THE LOWER OH VALLEY SUNDAY EVENING EWD TO CENTRAL NC BY 12Z MONDAY. A PLUME OF MOISTURE AND PERHAPS A NARROW BAND OF LIGHT SHOWERS ALONG THE ATTENDANT COLD FRONT AND INVOF OF THE TRIPLE POINT WILL MOVE ACROSS CENTRAL NC IN THE PREDAWN HOURS. DESPITE NOTABLE COOLING ALOFT...ALL FORECAST SOUNDINGS ACROSS CENTRAL NC SHOW LOW LEVELS WARM ENOUGH FOR ALL RAIN WITH THIS BAND OF SHOWERS...EVEN ACROSS THE TRIAD. LOWS MONDAY MORNING IN THE MID TO UPPER 30S. DURING THE DAYTIME MONDAY...THE MID LEVEL TROUGH AXIS IS PROGGED TO CROSS CENTRAL NC...ALONG WITH THE TRIPLE POINT LOW TAKING OVER AND STRENGTHENING OFFSHORE OF KHSE. A FEW ADDITIONAL SHOWERS WILL BE POSSIBLE ACROSS OUR AREA (ESP OUR NORTHERN/NE ZONES) AS THE TROUGH AXIS MOVES ACROSS...BUT MOISTURE IS MODEST AND CONSENSUS MODEL QPF FOR THE DAYTIME MONDAY IS WELL UNDER ONE TENTH INCH. WITH THE BL WIND SHIFT TO N AND THE START OF LOW LEVEL CAA NOT OCCURRING UNTIL AFTER NOON...BOUNDARY LAYER TEMPS WILL BE WARM ENOUGH SUCH THAN ANY PRECIP DURING THE DAYTIME MONDAY SHOULD BE ALL RAIN. BY 00Z TUESDAY...FORECAST SOUNDINGS SUGGEST ENOUGH LOW LEVEL COOLING WILL HAVE OCCURRED THAT ANY LINGERING SHOWERS ACROSS OUR NE ZONES (INVOF OF DEEPER MOISTURE UNDER THE TROUGH AXIS) MAY MIX WITH OR CHANGE TO SNOW SHOWERS. BUT AGAIN...KEEP IN MIND THAT MODEL QPF VALUES ARE VERY LIGHT...SO PERHAPS ONLY FLURRIES OR VERY LIGHT SNOW SHOWERS WITH NO ACCUM...IF ANY PRECIP AT ALL. AS ALWAYS THE CASE WITH THESE SYSTEMS...IT`S A CLOSE TIMING ISSUE BETWEEN ARRIVAL OF COLDER AIR AND DEPARTURE OF MOISTURE. MONDAY NIGHT...ANOTHER TRAILING SHORT WAVE IS PROGGED TO DIVE SOUTH FROM THE GREAT LAKES REGION...REACHING THE MID ATLANTIC REGION BY TUESDAY MORNING OR AFTERNOON. WHILE THE AIRMASS ACROSS OUR AREA BY THEN WOULD BE COLD ENOUGH FOR SNOW...THE DEEPEST MOISTURE AND BEST CHANCE FOR ANY PRECIP APPEARS TO REMAIN TO OUR NORTH AND EAST PER GFS...OR LITTLE IF ANY MOISTURE AT ALL ACROSS OUR AREA PER ECMWF. FOR NOW...WILL KEEP POPS LOW ACROSS OUR AREA GIVEN LOW CONFIDENCE. HIGHS ON TUESDAY WILL BE DEPENDENT ON PRECIP CHANCES...BUT FOR NOW WILL MAINTAIN LOWER 40S. FAIR WEATHER WEDNESDAY THROUGH EARLY THURSDAY IN THE WAKE OF THE DEPARTING TROUGH...BUT TEMPS BELOW NORMAL THANKS TO DEEP N-NW FLOW. YET ANOTHER SHORT WAVE WILL QUICKLY APPROACH LATE THURSDAY AND MOVE ACROSS EARLY FRIDAY. RIGHT NOW THE MODELS SUGGEST A DRY TROUGH PASSAGE THANKS TO ANTECEDENT DRY NW FLOW. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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AS OF 1240 AM SATURDAY... 24 HOUR TAF PERIOD: HEAVIEST PRECIPITATION THIS MORNING REMAINING SOUTH AND EAST OF THE AREA. WE WILL BE ENTERING A LULL IN THE PRECIPITATION FOR THE NEXT SEVERAL HOURS WHERE DRIZZLE OR VERY LIGHT RAIN WILL BE THE PREDOMINANT MODE OF PRECIPITATION. HIGH RESOLUTION MODELS SHOW SOME PRECIPITATION FILLING BACK IN AFTER 9Z FROM RALEIGH EASTWARD TO THE COAST WITH DRIZZLE TO LIGHT RAIN STILL POSSIBLE IN THE WEST. MODELS HOLD ON TO PRECIPITATION THROUGH 18Z ALTHOUGH IT MAY PULL OUT TO THE NORTHEAST EARLIER THAN THAT. ONCE IT MOVES OUT. THE REMAINDER OF THE TAF PERIOD IS EXPECTED TO BE DRY. CEILINGS WILL MOST LIKELY REMAIN IFR/LIFR THROUGH MID MORNING OR SO BEFORE STEADILY IMPROVING BACK TO VFR. SKIES WILL EVENTUALLY CLEAR BY LATE AFTERNOON. VISIBILITIES MEANWHILE SHOULD REMAIN IN THE IFR/MVFR RANGES THROUGH A SIMILAR TIME PERIOD BEFORE RETURNING TO VFR. WITH PRECIPITATION AND WINDS STAYING UP A LITTLE OVERNIGHT...DO NOT EXPECT MUCH OF A DENSE FOG THREAT. WINDS WILL VARY FROM CALM TO 10 KTS THROUGH THE MORNING WITH SOME VARYING DIRECTION AS WELL BUT WITH SOME NORTHERLY COMPONENT. BY AFTERNOON WINDS WILL BACK AROUND TO WESTERLY WITH SUSTAINED WINDS NEAR 10 KTS GUSTING TO 20 KTS. GUSTS WILL SUBSIDE AFTER SUNSET WITH WINDS OUT OF THE WEST AT 5-10 KTS. LONG TERM: MAINLY VFR CONDITIONS FOR THE LONG TERM AFTER THE CURRENT SYSTEM MOVES OFF. THE EXCEPTION TO THIS COULD BE WITH A CLIPPER SYSTEM ON MONDAY THROUGH MONDAY NIGHT WHICH COULD PRESENT A FEW PERIODS OF SUB VFR CONDITIONS.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...BADGETT LONG TERM...NP AVIATION...ELLIS

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