Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 311730 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 130 PM EDT FRI OCT 31 2014 .SYNOPSIS...A POWERFUL STORM SYSTEM WILL AFFECT THE AREA TONIGHT THROUGH SATURDAY NIGHT. LOW PRESSURE WILL DEVELOP OVER THE WESTERN CAROLINAS THIS AFTERNOON... THEN TRACK EAST TOWARD THE COAST TONIGHT. THIS COASTAL LOW WILL THEN RAPIDLY STRENGTHEN AND TURN NORTHEASTWARD ALONG THE MID ATLANTIC COAST SATURDAY AND SATURDAY NIGHT. COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST SATURDAY NIGHT THROUGH MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM FRIDAY... REST OF TODAY: EARLIER FORECAST IS ON TRACK. A LARGE AREA OF STRATOCU HAS HAMPERED THE TEMP RISE SOMEWHAT OVER THE NORTHWEST PIEDMONT... BUT OTHERWISE ABUNDANT SUNSHINE AHEAD OF OUR INCOMING STORM HAS ALLOWED TEMPS TO RISE THROUGH THE LOWER 50S SO FAR... ON PACE TO REACH HIGHS IN THE LOW-MID 60S (EXCEPT FOR UPPER 50S TO NEAR 60 IN THE NW). THE COASTAL LOW JUST OFF THE OUTER BANKS AND ITS ASSOCIATED PRECIP AND CLOUD SHIELD CONTINUES TO MOVE NE AWAY FROM THE FORECAST AREA... AND SUBSIDING AND FAIRLY DRY AIR IN ITS IMMEDIATE WAKE SHOULD YIELD SEVERAL HOURS OF SUNSHINE OVER MUCH OF CENTRAL NC. THE NW PIEDMONT LOWER CLOUDINESS SHOULD PIVOT NE OUT OF THE AREA... ALLOWING AT LEAST PARTIAL SUNSHINE... HOWEVER ENCROACHING MID CLOUDS FROM THE W AND SW WILL LIMIT FULL HEATING THERE. EXTRAPOLATION OF SCATTERED TO NUMEROUS SHOWERS NOW OVER ERN KY/ERN TN INTO NE AL/NW GA BRINGS THIS ACTIVITY INTO OUR WRN CWA BY MID TO LATE AFTERNOON... A FEW HOURS FASTER THAN THE LATEST HRRR RUNS BUT VERY CLOSE TO OUR EXISTING FORECAST... SO LITTLE TO NO CHANGE NEEDED THERE FOR NOW. -GIH PREVIOUS DISCUSSION AS OF 330 AM: RELATIVE CALM BEFORE THE STORM TODAY. A NARROW RIDGE OF 1018 MB HIGH PRESSURE WAS ANALYZED AT 07Z OVER THE MIDDLE ATLANTIC AND WESTERN CAROLINAS THIS MORNING...IN BETWEEN A DEVELOPING COASTAL LOW ALONG THE OLD FRONTAL ZONE A FEW HUNDRED MILES OFF THE COAST OF THE CAROLINAS AND A TRIO OF FLATTER WAVES OVER NORTHERN MS; WESTERN KY; AND NORTHERN MI. ALOFT...THREE DISTINCT SHORTWAVE TROUGHS ARE EVIDENT IN WV IMAGERY IN ASSOCIATION WITH THE SURFACE WAVES - ONE OFF THE SE COAST...ANOTHER OVER THE MID-SOUTH...AND THE MOST POTENT ONE OVER THE WESTERN GREAT LAKES. THE LATEST SUITE OF NWP GUIDANCE IS SLIGHTLY FARTHER SOUTH WITH THE SHARPLY AMPLIFYING SHORTWAVE TROUGH AND ASSOCIATED CLOSED LOW EVOLUTION THROUGH THE CAROLINAS...AND THE ACCOMPANYING PRIMARY SURFACE LOW FORECAST TO CROSS THE CAROLINAS TONIGHT. THE STRONGEST LOW LEVEL CAA AND ALREADY-ONLY MARGINAL OPPORTUNITY FOR ANY WET FLAKES HAS CONSEQUENTLY SHIFTED SOUTH TO THE SOUTHERN NC PIEDMONT. THE RELATIVE HIGHEST CHANCES OF RAIN...AND PRECIPITATION AMOUNTS...WILL ALSO ACCORDINGLY BE FOCUSED IN AN ARC FROM WESTERN NC TO NORTHERN SC TO EASTERN NC...AS THE SURFACE LOW AND DEFORMATION ZONE EVOLVE IN A REGION OF STRONG ASCENT FUELED BY BOTH THE "DYNAMICS" ALOFT AND STRONG LOW-MID LEVEL FGEN. THE WEAK LEAD SURFACE WAVES OVER NORTHERN MS AND WESTERN KY ARE FORECAST TO CONTINUE EAST...BENEATH THE PARENT SHORTWAVE TROUGH...AND MERGE INTO A SINGLE LOW IN THE LEE OF THE APPALACHIANS THIS AFTERNOON. THIS LEE LOW WILL THEN REMAIN RELATIVELY STATIONARY AS THE STRONGEST HEIGHT FALLS ACCOMPANYING THE POTENT SHORTWAVE AMPLIFYING SHARPLY SSE FROM THE WESTERN GREAT LAKES TO THE SOUTHERN APPALACHIANS ALLOWS THE TRAILING SURFACE LOW OVER NORTHERN MI AND ASSOCIATED PRESSURE FALLS TO CATCH UP TO AND "CAPTURE" THE LEAD LEE LOW...WITH THE THEN MERGED SURFACE LOW FORECAST TO MOVE DUE EAST INVOF THE SC/NC BORDER TONIGHT. SHALLOW CONVECTION...INCLUDING SPORADIC LIGHTNING IN AN ENVIRONMENT CHARACTERIZED BY MUCAPE OF UP TO A FEW HUNDRED J/KG...WILL EASE EAST FROM THE SC UPSTATE AND NC FOOTHILLS...INTO THE NC SOUTHERN AND WESTERN PIEDMONT ROUGHLY BETWEEN 7-10 PM. THESE SHOWERS AND ISOLATED STORMS WILL MAKE ONLY SLOW EASTWARD PROGRESS ACROSS THOSE AREAS THROUGH MIDNIGHT...BEFORE THE CHARACTER OF THE PRECIPITATION ASSUMES AN INCREASINGLY STRATIFORM PRECIPITATION SHIELD WITH EMBEDDED SHALLOW CONVECTIVE ELEMENTS LINGERING OWING TO STRONG MID LEVEL CAA ATOP A WARM/MOIST TONGUE WRAPPED CYCLONICALLY BENEATH THE COLD POOL ALOFT...AROUND THE DEVELOPING LOW LEVEL CYCLONE. RAIN...WITH ASSOCIATED AMOUNTS BETWEEN ONE HALF AND ONE INCH...WILL CONSEQUENTLY GRADUALLY PIVOT ACROSS THE SANDHILLS AND CENTRAL PIEDMONT THROUGH DAYBREAK...WITH MUCH OF THE COASTAL PLAIN AND FAR NE PIEDMONT LIKELY TO EXPERIENCE ONLY OCCASIONAL LIGHT RAIN AND AMOUNTS LESS THAN A TENTH OF AN INCH. FORECAST PARTIAL THICKNESS VALUES HOLD IN THE INDETERMINATE RANGE THROUGHOUT CENTRAL NC FROM EVEN THE COLDEST EC/NAM GUIDANCE...AND BUFR SOUNDINGS EVEN IN THE SOUTHERN AND WESTERN PIEDMONT LIKEWISE MAINTAIN A COUPLE OF THOUSAND FT ABOVE FREEZING BOUNDARY LAYER. LOWS GENERALLY IN THE UPPER 30S TO MIDDLE 40S FROM WEST TO EAST...AFTER HIGHS TODAY IN THE UPPER 50S TO MIDDLE 60S. -MWS && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
-- Changed Discussion --
AS OF 130 PM FRIDAY... FAIR BUT UNSEASONABLY COOL WEATHER IS EXPECTED ON SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST IN THE WAKE OF THE DEPARTING TROUGH. FORECAST SOUNDINGS AND CROSS SECTIONS SUGGEST A FEW LINGERING MID-LEVEL CLOUDS AT THE START OF THE DAY...BUT SKIES SHOULD BECOME MOSTLY SUNNY BY AFTERNOON GIVEN DRY NW FLOW. A LITTLE BREEZY STILL IN THE MORNING AND EARLY AFTERNOON WHILE THE HIGH IS BUILDING IN...UNTIL THE PRES GRADIENT RELAXES LATER IN THE DAY. LOW LEVEL THICKNESSES ARE PROGGED TO BOTTOM OUT ABOUT 50M BELOW AVERAGE...AROUND 1300M EARLY SUNDAY...RECOVERING TO 1315M BY LATE- DAY. THIS SUGGESTS HIGHS IN THE LOWER 50S...ABOUT 15 DEG BELOW NORMAL. HIGH PRESSURE IS THEN PROGGED TO BECOME CENTERED OVER THE CAROLINAS BY MONDAY MORNING. GIVEN THE AIRMASS IN PLACE...LIGHT WINDS UNDER THE HIGHS...AND MAINLY CLEAR SKIES...THE EXPECTATION IS STILL THERE THAT MOST OF OUR CWA WILL SEE A GROWING-SEASON-ENDING FROST OR FREEZE MONDAY MORNING. HOWEVER...WILL NEED TO KEEP A CLOSE WATCH FOR THE POTENTIAL FOR SOME OROGRAPHIC CIRRUS...GIVEN NW FLOW AND SOME MOISTURE SPILLING OVER THE MID RIDGE AXIS. WHILE CONFIDENCE IN THIS HAPPENING IS CUSTOMARILY LOW RIGHT NOW (3 DAYS OUT)...IF IT DOES MATERIALIZE...LOOKS LIKE IT WOULD BE MOSTLY ACROSS OUR FAR WESTERN ZONES...SO A DECENT FROST/FREEZE EVENT ACROSS MOST OF OUR CWA STILL LOOKS LIKELY. FOR NOW...WILL LEAVE LOWS AS-IS...RANGING FROM THE UPPER 20S WEST TO LOWER 30S EAST.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 130 PM FRIDAY... RIDGING AT SFC AND ALOFT WILL PROVIDE NICE WEATHER ACROSS CENTRAL NC MONDAY AND TUESDAY. THICKNESSES WILL CONTINUE MODERATING DURING THIS TIME...HOWEVER WITH THE SFC HIGH STILL CENTERED OVER US MONDAY NIGHT...LOOK FOR LOWS A COUPLE DEGREES BELOW NORMAL TUESDAY MORNING...UPPER 30S TO AROUND 40. HIGHS MONDAY AROUND 60 AND MID-UPR 60S ON TUESDAY. BY LATE TUESDAY...THE HIGH CENTER WILL MOVE OFF THE COAST...BUT THE RIDGE AXIS WILL REMAIN EXTENDED ACROSS THE CAROLINAS. WITH LOW LEVEL FLOW BECOMING MORE SWLY AND A THICKENING CANOPY OF CIRRUS WITH ENHANCED SW FLOW ALOFT OVER US...LOWS WEDNESDAY MORNING WILL BE WARMER...IN THE MID-UPR 40S. THE NEXT NORTHERN STREAM SHORT WAVE WILL BEGIN APPROACHING OUR REGION DURING THE DAY WEDNESDAY AND IT`S ASSOC COLD FRONT CROSSING CENTRAL NC LATE THURSDAY. THUS...WEDNESDAY WILL SEE INCREASING CLOUDINESS AND WARMING NICELY AHEAD OF THE FRONT...BUT REMAINING DRY. THE BEST CHANCE FOR ANY RAIN WITH THIS SYSTEM WILL BE ON THURSDAY ALONG AND JUST AHEAD OF THE FRONT...BUT MOISTURE PROFILES ACROSS OUR AREA ARE MODESTLY MOIST AT BEST...SO FOR NOW...WILL KEEP POPS LIMITED TO 20 PERCENT OR LESS ON THURSDAY. HIGHS CLIMBING ABOVE NORMAL (AROUND 70) FOR WEDNESDAY AND THURSDAY. RIGHT NOW...NEXT FRIDAY LOOKS TO BE BREEZY AND COOLER IN THE WAKE OF THE FRONT...WITH DECREASING CLOUDINESS THROUGH THE DAY. HIGHS COOLING BACK DOWN TO NEAR OR BELOW NORMAL FOR WEEKS END.
-- End Changed Discussion --
&& .CLIMATE... RECORD LO-MAX TEMPERATURES FOR NOVEMBER 1ST LO-MAX RDU 50/1925 GSO 45/1925 FAY 48/1988 && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 1255 PM FRIDAY... PATCHES OF MVFR STRATOCU WILL LINGER AT INT/GSO DURING THE FIRST COUPLE OF HOURS OF THIS TAF FORECAST PERIOD... BUT THEN CIGS SHOULD LIFT TO VFR PRIOR TO 20Z. OTHERWISE... AT RDU/RWI/FAY... VFR CONDITIONS WILL DOMINATE THROUGH 00Z. WE`RE CURRENTLY IN GENERALLY TRANQUIL WEATHER BETWEEN LOW PRESSURE OFF THE OUTER BANKS AND A POWERFUL STORM SYSTEM OVER SW MI THAT WILL DIVE SOUTH THEN SE... CROSSING THE CAROLINAS LATE TONIGHT THROUGH SAT. CIGS ARE EXPECTED TO DROP TO MVFR ONCE AGAIN AT INT/GSO WITH PATCHY RAIN BETWEEN 00Z AND 02Z... FOLLOWED BY A DROP TO IFR/LIFR CIGS AND MVFR/IFR VSBYS IN STEADY RAIN MOST LIKELY STARTING 02Z-04Z THIS EVENING. EXPECT THESE SUB-VFR CONDITIONS (DOWN TO MVFR IN PATCHY RAIN THEN TO IFR/LIFR WITH MORE STEADY RAIN) TO SPREAD EAST INTO RDU BETWEEN 04Z AND 08Z TONIGHT... AND INTO RWI/FAY BETWEEN 08Z AND 12Z SAT MORNING. CIGS MAY REBOUND A BIT SAT MORNING BUT MVFR OR IFR CONDITIONS ARE LIKELY TO STILL PREVAIL AT ALL SITES AFTER 12Z SAT. CONCERN FOR BRISK GUSTY WINDS WILL INCREASE TOWARD THE END OF THE TAF VALID PERIOD... AFTER 13Z SAT... WHEN SURFACE WINDS MAINLY FROM THE NORTH WILL START TO INCREASE TO SUSTAINED 15-20 KTS GUSTING TO 25-30 KTS. LOOKING BEYOND 18Z SAT: STRONG GUSTY SURFACE WINDS WILL CONTINUE SAT AFTERNOON AND EVENING AS THEY SHIFT FROM NORTH TO NORTHWEST AS THE LOW STRENGTHENS OFF THE COAST. CIGS EXPECTED TO GRADUALLY RISE TO VFR AS RAIN CHANCES TAPER OFF AT INT/GSO 21Z-00Z AND 23Z-04Z SAT EVENING AT RDU/RWI/FAY... WITH WINDS DECREASING SLOWLY LATE SAT NIGHT INTO SUN MORNING. VFR CONDITIONS WILL THEN HOLD UNDER COLD HIGH PRESSURE THROUGH WED. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS/HARTFIELD NEAR TERM...HARTFIELD/MWS SHORT TERM...NP LONG TERM...NP CLIMATE...CBL AVIATION...HARTFIELD

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.