Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 290050 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 745 PM EST SUN DEC 28 2014 .SYNOPSIS...
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A COLD FRONT WILL MOVE SOUTH THROUGH THE REGION LATER TONIGHT AND EARLY MONDAY. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT AND MOVE ACROSS THE REGION MONDAY. THE FRONT WILL MOVE OFFSHORE MONDAY NIGHT BEFORE HIGH PRESSURE EXTENDS INTO THE REGION ON TUESDAY.
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&& .NEAR TERM /THROUGH MONDAY/...
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AS OF 730 PM SUNDAY... THE MAIN COLD FRONT REMAINED TO OUR NW THIS EVENING. RAIN WAS CONFINED TO JUST BEHIND THE FRONT OVER EASTERN TENNESSEE INTO SOUTHWEST VIRGINIA MOVING EASTWARD. VERY LITTLE TO NO SHOWERS ARE NOTED OUT AHEAD OF THE COLD FRONT OVER CENTRAL AND EASTERN NORTH CAROLINA. IN THE MEAN TIME... THERE HAVE BEEN ENOUGH BREAKS IN THE CLOUDS OVER THE WESTERN SANDHILLS AND SOUTHERN/EASTERN PIEDMONT FOR THE DEVELOPMENT OF PATCHY FOG... SOME DENSE... IN AREAS WHERE SOME LIGHT RAIN FELL EARLIER. WE WILL ADD SOME PATCHY DENSE FOG IN AREAS FROM NEAR ALBEMARLE AND TROY NE THROUGH THE SANFORD AND SILER CITY AREAS TO NEAR AND INCLUDING ROXBORO. AS COLD FRONT DROPS SOUTH INTO NORTHERN NORTH CAROLINA AFTER MIDNIGHT... CLOUDS WILL THICKEN AND WINDS WILL SHIFT TO THE NE AT 5-10 MPH. THIS WILL SCOUR OUT THE FOG. OTHERWISE... CENTRAL NC IS JUST WAITING ON THE FRONT TO DIP INTO THE REGION AND THE FINAL WAVE TO FORM ON THE FRONT LATER TONIGHT. A GOOD AREA OF FORCING FOR LIFT WILL DEVELOP BEHIND THE FRONT WITH THE INCREASE IN WAA AND VERY MOIST FLOW ALOFT AS THE MID/UPPER LEVEL TROUGH APPROACHES FROM THE WEST. IT APPEARS THAT MUCH OF OUR RAINFALL WILL BE ANAFRONTAL OR JUST BEHIND THE COLD FRONT LATER TONIGHT INTO MONDAY MORNING GIVEN THE FAVORABLE CONDITIONS MENTIONED ABOVE. THEREFORE... EXPECT THICKENING CLOUDS AND DECREASING FOG OVERNIGHT WITH RAIN DEVELOPING IN ALL BUT THE SE ZONES. THE SE ZONES SHOULD SEE THE RAIN DEVELOP AROUND SUNRISE AS THE FRONT SLIPS TO THE SOUTH. QPF OF 0.50 TO 0.75 IS EXPECTED WITH THIS EVENT... WITH LESSER AMOUNTS IN THE SE (0.25 TO 0.50 MONDAY). TEMPERATURES SHOULD HOLD IN THE MID 50S TO AROUND 60 SE... BUT FALL INTO THE 40S NORTH LATER TONIGHT. THE RAIN WILL GRADUALLY TAPER TO DRIZZLE MONDAY AFTERNOON AS THE FAVORABLE UPPER JET AND WARM CONVEYOR BELT RAINS MOVE TO THE NE. TEMPS WILL FALL INTO 40S AND 50S FROM THE CENTRAL TO THE SOUTHERN ZONES WITH THE LOW OVERCAST AND NE FLOW.
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&& .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... AS OF 305 PM SUNDAY... MONDAY NIGHT INTO TUESDAY... ATMOSPHERE BELOW 700MB TO REMAIN NEARLY SATURATED AS 925-850MB TROUGH REMAINS WEST OF THE FORECAST AREA UNTIL TUESDAY AFTERNOON. LIFT TO GENERATE APPRECIABLE PRECIPITATION LACKING THOUGH 12Z/NAM DOES DEPICT WEAK UPGLIDE AT 290K LEVEL OVER OUR REGION LATE MONDAY NIGHT-TUESDAY MORNING (GFS DEPICTS NEUTRAL ADVECTION). MARGINAL UPSLOPE FLOW AT 925 MB MAY GENERATE SPOTS OF LIGHT RAIN OVER THE NW PIEDMONT OTHERWISE EXPECT AREAS OF DRIZZLE MONDAY NIGHT THROUGH TUESDAY MORNING. PASSAGE OF 925-850MB TROUGH A LITTLE SLOWER COMPARED TO MODEL GUIDANCE 24 HOURS AGO. WHILE PARTIAL CLEARING STILL EXPECTED ACROSS THE FAR WEST-NW PRIOR TO SUNSET...PARTIAL CLEARING MAY NOT MAKE IT TO THE TRIANGLE AREA OR TO THE SANDHILLS AND COASTAL PLAIN UNTIL AFTER SUNSET. MIN TEMPS MONDAY NIGHT MID-UPPER 30S NORTH TO THE LOWER 40S SOUTH. TEMPS TUESDAY WILL BE HELD DOWN BY EXTENSIVE CLOUDS AND PATCHY LIGHT RAIN/DRIZZLE. MAX TEMPS TUESDAY LOW-MID 40S NORTH TO THE UPPER 40S/AROUND 50 SOUTH. TUESDAY NIGHT...PASSAGE OF 925-850MB TROUGH LATE TUESDAY-TUESDAY NIGHT SHOULD INITIATE SOME PARTIAL CLEARING DUE TO SUBSIDENCE AND DOWNSLOPE COMPONENT OF LOW LEVEL WINDS. SOME GUIDANCE SUGGEST LOW CLOUDS HOLDING ON IN THE EAST UNTIL SHORTLY AFTER DAYBREAK WEDNESDAY. IF PARTIAL CLEARING OCCURS...MAY SEE PATCHY/AREAS OF FOG DEVELOP AFTER MIDNIGHT. MIN TEMPS UPPER 20S FAR NORTH-NW TO AROUND 30 FAR SOUTH. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 305 PM SUNDAY... WEDNESDAY AND THURSDAY...S/W IN THE NORTHERN STREAM WILL CROSS THE GREAT LAKES AND NORTHERN MID ATLANTIC LATE WEDNESDAY AND WEDNESDAY NIGHT. THIS FEATURE WILL PROPEL A DRY SURFACE COLD FRONT ACROSS CENTRAL NC WEDNESDAY NIGHT. THIS PASSAGE WILL OCCUR PRETTY UNEVENTFUL WITH JUST A DECK OF MID-HIGH LEVEL CLOUDS EXPECTED. THUS PARTIAL CLEARING EARLY WEDNESDAY EXPECTED TO BE SHORT-LIVED AS APPROACH OF S/W AND ASSOCIATED MID-HIGH LEVEL CLOUDINESS WILL CROSS CENTRAL NC LATE WEDNESDAY AND WEDNESDAY EVENING. NLY WINDS BEHIND THIS PASSAGE WILL REINFORCE THE COOL AIR MASS ALREADY IN PLACE BUT ADVECT A BATCH OF DRIER AIR AS DEWPOINTS WILL LOWER INTO THE TEENS/LOWER 20S. LOW LEVEL THICKNESSES BY EARLY THURSDAY ARE IN THE 1290-1295M RANGE. HISTORICALLY...THIS SUPPORTS MIN TEMPS IN THE MID-UPPER 20S. THE COOL DRY AIR MASS FOR THURSDAY WILL SUPPORT MOSTLY SUNNY SKIES FOR THE FIRST DAY OF 2015 WITH AFTERNOON TEMPS WILL AVERAGE 5-6 DEGREES BELOW NORMAL. HIGH TEMPS THURSDAY MID 40S NORTH TO NEAR 50 SOUTH. FRIDAY THROUGH SUNDAY... WEATHER PATTERN OVER CENTRAL NC BECOMES UNSETTLED AS AN UPPER LEVEL LOW WILL SLUGGISHLY LIFT EAST-NE ACROSS THE MID MS AND OH VALLEYS. MODEL GUIDANCE OFFER DIFFERING SOLUTIONS WITH TEH GFS MORE PROGRESSIVE THAN THE ECMWF. USUALLY...BETTER TO LEAN TOWARD THE SLOWER SOLUTION THIS FAR OUT. EXPECT AIR MASS TO MODIFY FRIDAY AS AS FLOW ASSUMES A RETURN FLOW OFF THE ATLANTIC. PRECIP CHANCES WILL LIKELY BEGIN TO INCREASE LATE FRIDAY...AND MORE SO SATURDAY PERSISTING INTO SUNDAY. PRESENCE OF A MODIFIED ARCTIC AIR MASS IN PLACE OVER CENTRAL NC PRIOR TO PRECIP ARRIVAL SIGNAL POTENTIAL FOR HYBRID OR INSITU COLD AIR DAMMING SATURDAY INTO THIS SUNDAY. IF THIS MATERIALIZES...THIS WOULD CREATE A WIDE VARIANCE IN TEMPS ACROSS CENTRAL NC (CHILLY NW TO RELATIVELY MILD SE). FOR NOW...WILL KEEP MAX TEMPS CLOSE TO AVERAGE ACROSS THE PIEDMONT...AND A CATEGORY OR TWO ABOVE NORMAL IN THE SE. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 655 PM MONDAY... AVIATION CONDITIONS ARE EXPECTED TO DETERIORATE OVERNIGHT AS A WAVY SLOW MOVING COLD FRONT MOVES THROUGH THE AREA OVERNIGHT. CEILINGS WILL FALL INTO THE IFR RANGE AROUND 04-06Z AT KINT/KGSO...AROUND 06- 08Z AT KRDU/KRWI AND AROUND 09-11Z AT KFAY AS A SEVERAL HOUR PERIOD OF LIGHT TO OCCASIONALLY MODERATE RAIN SPREADS INTO THE REGION. SOUTHWESTERLY WINDS AHEAD OF THE FRONT WILL BECOME NORTHERLY AT 5- 10KTS BEHIND THE FRONT AND EVENTUALLY BECOME NORTHEASTERLY ON MONDAY. MEASURABLE PRECIP CHANCES WILL DIMINISH MONDAY AFTERNOON BUT A MOIST 1000-950MB NELY FEED WILL SUPPORT IFR TO LIFR CEILINGS INTO TUESDAY. LOOKING AHEAD...LINGERING LOW CLOUDS ALONG WITH SOME LIGHT RAIN AND DRIZZLE WILL CONTINUE INTO TUESDAY AND WILL BEGIN TO IMPROVE LATE TUESDAY AND WEDNESDAY. FAIR WEATHER AND NO ADVERSE AVIATION CONDITIONS ARE EXPECTED WEDNESDAY THROUGH EARLY FRIDAY BEFORE THE NEXT STORM SYSTEM APPROACHES LATE FRIDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLAES NEAR TERM...BADGETT SHORT TERM....WSS LONG TERM...WSS AVIATION...CBL/BLAES

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