Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 280548 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1250 AM EST FRI NOV 28 2014 .SYNOPSIS...HIGH PRESSURE WILL BUILD OVER THE REGION FROM THE WEST TODAY...AND SETTLE OVERHEAD TONIGHT AND SATURDAY. THE HIGH WILL DRIFT OFFSHORE BY SUNDAY RESULTING IN A WARM SOUTHWEST FLOW OVER OUR AREA. && .NEAR TERM /THROUGH FRIDAY NIGHT/... AS OF 1030 PM THURSDAY... TONIGHT: A LARGE AREA OF HEIGHT RISES ALOFT FROM THE SOUTHERN APPALACHIANS TO THE NORTHERN PLAINS...BEHIND A TROUGH LIFTING AWAY FROM THE MIDDLE ATLANTIC STATES...WILL CONTINUE TO SPREAD EAST A.ND ACROSS CENTRAL NC TONIGHT. BENEATH THESE HEIGHT RISES ALOFT AND ASSOCIATED SUBSIDENCE...1033 MB CONTINENTAL POLAR HIGH PRESSURE WILL LIKEWISE BUILD EAST FROM THE MID-MS VALLEY...RESULTING IN CAA AND A LIGHT NW WIND FOR MOST OF THE NIGHT - SUPPORTIVE OF LOWS MOSTLY IN THE MIDDLE TO UPPER 20S...THOUGH SOME LOWER 20S ARE PROBABLE BY DAYBREAK WHERE SUSTAINED CALM DEVELOPS (MOST LIKELY OVER THE SOUTHERN AND WESTERN PIEDMONT). WHILE A FEW STREAMERS OF STRATOCUMULUS MAY SQUEEZE BETWEEN THE RIDGES INTO THE PIEDMONT... LIKE ONE SUCH PATCH FROM NEAR KTDF TO KRDU AT 03Z...SKIES WILL OTHERWISE BE CLEAR. . FOR FRI/FRI NIGHT: A QUIET DAY AND NIGHT WITH HIGH PRESSURE BUILDING OVERHEAD AND STRONGLY SUBSIDING MID LEVELS. EXPECT HIGH PRESSURE BUILDING INTO THEN SETTLING OVER THE CAROLINAS THROUGH SATURDAY WILL PROVIDE VFR CONDITIONS. THE HIGH WILL DRIFT OFFSHORE SATURDAY NIGHT INTO SUNDAY. THE RESULTANT SLY FLOW WILL ADVECT LOW LEVEL MOISTURE...INCREASING THE PROBABILITY FOR PATCHES OF MVFR/IFR FOG SUNDAY MORNING AND AGAIN MONDAY MORNING. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY AND CROSS THE REGION MONDAY NIGHT. THIS WEATHER SYSTEM WILL INCREASE THE THREAT FOR MVFR CEILINGS AND AREAS OF RAIN MONDAY NIGHT INTO TUESDAY.LOTS OF SUNSHINE DURING THE DAY. THE THERMAL TROUGH LIFTS OUT DURING THE LATTER HALF OF THE DAY... AND THICKNESSES ACCORDINGLY REBOUND CONSIDERABLY (ALTHOUGH THIS 1000-850 MB LAYER GRABS SOME OF THE WARMER AIR A.BOVE THE SUBSIDENCE INVERSION). USING A LOW LEVEL DRY ADIABATIC PROFILE TO 925 MB INDICATES HIGHS OF 42-46... A SLIGHT LEAN TO THE COOL SIDE OF GUIDANCE AND IN LINE WITH EARLIER FORECAST HIGHS. THE SURFACE RIDGE SHOULD BE OVERHEAD EARLY FRI NIGHT BUT SHIFTING EASTWARD LATE... SO WINDS SHOULD BE FAIRLY LIGHT WITH GENERALLY CLEAR SKIES... ALTHOUGH WE`LL SEE INCREASING HIGH CLOUDS LATE AS MINOR WAVES TRACK ESE INTO NC WITHIN THE FAST STEERING FLOW ALOFT. STILL EXPECT LOWS IN THE MID-UPPER 20S. -GIH && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 245 PM THURSDAY... HIGH PRESSURE WILL SHIFT OFFSHORE DURING THE DAY ON SATURDAY... ALLOWING RETURN FLOW TO FIRMLY SET UP OVER THE REGION FOR THE WEEKEND. IN ADDITION...MID LEVEL RIDGING WILL BUILD NORTH AND EAST ACROSS THE AREA. ALL OF THIS WILL LEAD TO FAIR WEATHER AND A WARMING TREND...WITH HIGHS EXPECTED TO BE IN THE LOW TO MID 50S ON SATURDAY AND THEN LOW TO MID 60S BY SUNDAY. OVERNIGHT LOWS WILL ALSO MODERATE THROUGH THE PERIOD...WITH MOSTLY MID/UPPER 30S SATURDAY NIGHT AND THEN MID/UPPER 40S SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 245 PM THURSDAY... A NORTHERN STREAM SHORT WAVE MOVING ALONG THE US/CANADIAN BORDER WILL SUPPRESS THE MID LEVEL RIDGE TO THE SOUTH AS IT PROPELS A SURFACE FRONT TOWARDS THE REGION EARLY NEXT WEEK. THIS TRAILING COLD FRONT IS STILL PROGGED TO CROSS THE AREA MONDAY NIGHT INTO TUESDAY. FORCING IS NOT THAT IMPRESSIVE WITH THIS SYSTEM GIVEN THE PARENT LOW IS SO FAR NORTH OF THE AREA. HOWEVER...GIVEN SOME CONVERGENCE AND MOISTURE POOLING ALONG THE BOUNDARY...WILL MAINTAIN SLIGHT CHANCE POPS IN THE FORECAST. HIGHS WILL WARM UP NICELY WITHIN THE DEEP SOUTHWESTERLY FLOW AHEAD OF THE FRONT...WITH MID TO UPPER 60S (NEAR 70 DEGREES ACROSS THE SOUTHEAST) EXPECTED. TEMPS WILL BE COOLER BEHIND THE FRONT ON TUESDAY...WITH HIGHS GENERALLY IN THE UPPER 40S TO MID/UPPER 50S (COOLEST IN THE NORTHWEST WHERE SOME CAD MAY DEVELOP). QUITE A BIT OF UNCERTAINTY THEN PERSISTS FOR THE REMAINDER OF THE FORECAST PERIOD AS ANOTHER SYSTEM (POSSIBLY) APPROACHES FROM THE NORTHWEST. THE ECMWF IS MUCH MORE AMPLIFIED/PROGRESSIVE WITH ANOTHER SHORT WAVE SWINGING THROUGH THE AREA WEDNESDAY INTO THURSDAY...WILL THE GFS IS MUCH LESS AMPLIFIED (WITH ZONAL FLOW ACTUALLY OVER THE MID ATLANTIC REGION). GIVEN THE DIFFERENCES...WILL KEEP ANY POPS LOW...WITH SEASONAL HIGHS/LOWS. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 1250 AM FRIDAY... HIGH PRESSURE BUILDING INTO THEN SETTLING OVER THE CAROLINAS THROUGH SATURDAY WILL PROVIDE VFR CONDITIONS. THE HIGH WILL DRIFT OFFSHORE SATURDAY NIGHT INTO SUNDAY. THE RESULTANT SLY FLOW WILL ADVECT LOW LEVEL MOISTURE...INCREASING THE PROBABILITY FOR PATCHES OF MVFR/IFR FOG SUNDAY MORNING AND AGAIN MONDAY MORNING. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY AND CROSS THE REGION MONDAY NIGHT. THIS WEATHER SYSTEM WILL INCREASE THE THREAT FOR MVFR CEILINGS AND AREAS OF RAIN MONDAY NIGHT INTO TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...MWS/HARTFIELD SHORT TERM...KRD LONG TERM...KRD AVIATION...WSS

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