Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 280331 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1031 PM EST THU NOV 27 2014 .SYNOPSIS...BENEATH HEIGHT RISES IN NORTHWESTERLY FLOW ALOFT...HIGH PRESSURE WILL BUILD OVER THE REGION FROM THE WEST THROUGH EARLY SATURDAY...BEFORE MOVING OFFSHORE LATE SATURDAY THROUGH SUNDAY. && .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 AND 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 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 ABOVE 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 /00Z FRIDAY THROUGH TUESDAY/... AS OF 719 PM THURSDAY... SCATTERED SHOWER ACTIVITY FROM THIS AFTERNOON HAS STEADILY DIMINISHED AFTER SUNSET. DRY WEATHER WITH VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. WINDS WILL CONTINUE TO BE LIGHT AND FROM THE NORTHWEST AT 5-10 KTS AS HIGH PRESSURE BUILDS INTO THE SOUTHEAST STATES. LOOKING BEYOND 18Z FRI... VFR CONDITIONS ARE EXPECTED TO DOMINATE THROUGH MON... ALTHOUGH AREAS OF MVFR OR IFR FOG ARE POSSIBLE EARLY SUN MORNING AND EARLY MON MORNING. HIGH PRESSURE WILL SHIFT EASTWARD OVER THE REGION THROUGH SAT... THEN MOVE EAST AND OFFSHORE SAT NIGHT/SUN. A COLD FRONT WILL MOVE IN FROM THE NORTH LATE MON OR MON NIGHT... BRINGING A GOOD CHANCE OF MVFR/IFR CONDITIONS MON NIGHT/TUE AND PATCHY LIGHT RAIN. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS/HARTFIELD SHORT TERM...KRD LONG TERM...KRD AVIATION...SEC/HARTFIELD

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