Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 210142 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 942 PM EDT WED MAY 20 2015 .SYNOPSIS...
-- Changed Discussion --
A DEVELOPING WEAK WAVE OF LOW PRESSURE WILL TRACK EAST ALONG A QUASI-STATIONARY FRONTAL BOUNDARY LATE TONIGHT THROUGH THURSDAY. DRIER CANADIAN HIGH PRESSURE WILL BUILD OVER THE CAROLINAS THROUGH THE WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /TONIGHT/...
-- Changed Discussion --
AS OF 942 PM WEDNESDAY... IMPRESSIVE CONVECTIVELY ENHANCED SEABREEZE MAKING INROADS INTO THE CENTRAL PIEDMONT. DRY/STABLE AIRMASS IN PLACE ACROSS CENTRAL NC HAS INHIBITED CONVECTIVE INITIATION ALONG THIS FEATURE...SECURING QUIET CONDITIONS THUS FAR THIS EVENING. HOWEVER...THINGS WILL BECOME INCREASINGLY UNSETTLED OVERNIGHT WITH THE APPROACH OF A WEAK SHORTWAVE TROUGH CURRENTLY ACROSS EASTERN TN/KY...WHICH IS PROGGED TO BE ON OUR WESTERN DOORSTEP BY DAYBREAK. WITH THE APPROACH OF THE WAVE...PREVIOUSLY STALLED FRONT TO OUR SOUTH AND WEAK WAVE OF LOW PRESSURE WILL RETREAT EVER SO SLIGHTLY NORTHWARD ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA...WHICH WILL ALLOW NEARBY UPPER 60 SFC DEWPOINTS AND ASSOCIATED WEAK BUOYANCY TO OVERSPREAD SOUTHERN PORTIONS OF THE FORECAST AREA. RAIN CHANCES WILL INCREASE BETWEEN 06 TO 12Z OWING TO STRENGTHENING LOW AND MID- LEVEL WARM ADVECTION AND WEAK DPVA INTO THE CAROLINAS FROM THE WEST. LOWS RANGING FROM LOWER 60S NE COASTAL PLAIN TO LOWER 70S SOUTH...ESP NEAR THE SC BORDER AND IN SW PIEDMONT.
-- End Changed Discussion --
&& .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 345 PM WEDNESDAY... OVERVIEW: MINOR SHORTWAVE ENERGY TRACKING INTO CENTRAL NC FROM THE WEST LATE TONIGHT WILL PROGRESS EAST TO THE NC/VA COAST BY 18Z THU AFTERNOON AND OFFSHORE SHORTLY THEREAFTER. MEANWHILE...POTENT SHORTWAVE ENERGY DIGGING INTO THE UPPER MS RIVER VALLEY TONIGHT WILL TRACK INTO THE OH VALLEY DURING THE DAY THU...PROGRESSING TO THE MID- ATLANTIC COAST THU NIGHT. A SFC LOW CENTERED IN VICINITY OF CHARLOTTE AT 12Z THU WILL TRACK EAST ALONG A NORTHWARD MOVING WARM FRONT (FRONT WILL STALL NEAR THE HWY 64 CORRIDOR)...PROGRESSING TO KINSTON/KENANSVILLE BY 18Z AND OFFSHORE BY 00Z...THOUGH A WEAK SFC TROUGH WILL LIKELY PERSIST OVER CENTRAL NC IN RESPONSE TO HEIGHT FALLS ATTENDANT POTENT SHORTWAVE ENERGY TRACKING EASTWARD THROUGH THE OH VALLEY INTO THE MID-ATLANTIC. MORNING: PRECIPITATION ASSOC/W WARM ADVECTION AND ELEVATED INSTABILITY ON THE EASTERN PERIPHERY OF THE SFC-H85 LOW THU MORNING WILL LIFT NORTHWARD INTO VA BY 15-18Z. ELEVATED SHOWERS MAY PERSIST ACROSS THE NORTHERN PIEDMONT AND NE COASTAL PLAIN IN VICINITY OF THE VA BORDER EARLY THU AFTERNOON...HOWEVER...WIDESPREAD ELEVATED CONVECTION WILL LIFT NORTHWARD THROUGH CENTRAL VA TO THE DELMARVA COAST BY MID AFTERNOON...IN CONCERT WITH THE BEST WARM ADVECTION AND IN CLOSER VICINITY TO STRONGER DPVA/HEIGHT FALLS ASSOC/W SHORTWAVE ENERGY TRACKING EASTWARD THROUGH THE OH VALLEY. AFTERNOON: PRIMARY FCST PROBLEM REVOLVES AROUND WHETHER OR NOT CONVECTION WILL RE-DEVELOP THU AFTERNOON...AND IF SO...COVERAGE/ INTENSITY...IN ADDITION TO HIGH TEMPS. RICH LOW-LEVEL MOISTURE WILL ADVECT NORTHWARD INTO CENTRAL NC ALONG THE EASTERN PERIPHERY OF THE SFC LOW THU AFTERNOON AS THE BOUNDARY STALLED TO THE SOUTH LIFTS NORTHWARD TO THE HWY 64 CORRIDOR AS A WARM FRONT...PARTICULARLY IN THE SANDHILLS AND SE COASTAL PLAIN WHERE DEWPOINTS WILL APPROACH UPPER 60S TO NEAR 70F AND FCST SOUNDINGS SUGGEST MODERATE DIURNAL DESTABILIZATION. WITH DPVA EXITING BY EARLY AFTERNOON AND ADDITIONAL SHORTWAVE ENERGY TOO FAR REMOVED FROM CENTRAL NC (OH VALLEY)... FORCING FOR ASCENT WILL LARGELY BE CONFINED TO LOW-LEVEL CONVERGENCE INVOF THE SFC LOW TRACKING EAST ALONG OR JUST SOUTH OF THE HWY 64 CORRIDOR. THOUGH WEAK/SHALLOW LOW-LEVEL CONVERGENCE ATTENDANT SFC TROUGHING WILL PERSIST THROUGH THE AFTERNOON...12Z GUIDANCE SUGGESTS THE BEST LOW-LEVEL CONVERGENCE (CENTER OF SFC LOW) WILL PROGRESS EAST OF THE I-95 CORRIDOR PRIOR TO PEAK HEATING (~18Z). FURTHERMORE...FCST SOUNDINGS INDICATE SIGNIFICANT DRYING AOA 700 MB FROM WEST-EAST THU AFTERNOON. GIVEN A TEMPORAL DISCONNECT BETWEEN THE BEST LOW-LEVEL FORCING/ DIURNAL DESTABILIZATION AND THE PRESENCE OF AN INCREASINGLY HOSTILE THERMODYNAMIC ENVIRONMENT (ENTRAINMENT OF DRY AIR AOA 700 MB)... IT IS POSSIBLE THAT AFTERNOON DEVELOPMENT WILL BE LIMITED TO SCATTERED SHOWER ACTIVITY OR POSSIBLY PRECLUDED ALTOGETHER. HOWEVER... UNCERTAINTY PERSISTS WITH REGARD TO THE PRECISE EVOLUTION OF THE APPROACHING SHORTWAVE/ATTENDANT SFC- LOW...AND A NARROW TEMPORAL/ SPATIAL WINDOW FAVORING THE DEVELOPMENT OF DEEP CONVECTION CANNOT BE ENTIRELY RULED OUT BETWEEN ~18-21Z IN THE SE COASTAL PLAIN. DEEP LAYER SHEAR WOULD BE SUFFICIENT FOR SUPERCELLULAR ORGANIZATION AND AN ATTENDANT POTENTIAL FOR SEVERE WIND/HAIL...SHOULD DEEP CONVECTION DEVELOP. WITH THE ABOVE IN MIND...OVERALL SVR THREAT (AND ANY TOR POTENTIAL) IS EXPECTED TO BE CONFINED TO COASTAL NC WHERE SFC-BASED CONVECTION IS MOST LIKELY TO OCCUR AND WHERE LOW-LEVEL SHEAR WILL BE MOST FAVORABLE ON THE EASTERN PERIPHERY OF THE SFC-H85 LOW. EXPECT HIGHS RANGING FROM THE LOWER/MID 70S N/NW TO MID 80S SE. THURSDAY NIGHT: EXPECT CLEARING SKIES AS A DRIER AIRMASS ADVECTS INTO THE REGION IN THE WAKE OF THE DEPARTING LOW. LOWS IN THE LOWER 50S. -VINCENT && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... AS OF 220 PM WEDNESDAY... DEEP WEST NORTHWEST FLOW WILL MAINTAIN WEAK COOL AIR ADVECTION TO OFFSET INCREASED INSOLATION ON FRIDAY AND FRIDAY NIGHT AS A LONG WAVE TROF AXIS SLOWLY ROTATES ACROSS THE AREA AND OFFSHORE. HIGHS WILL RANGE FROM THE MID 70S NORTH TO UPPER 70S SOUTH...WITH MINS FRIDAY NIGHT FALLING INTO THE MID 50S. RIDGING AT THE SURFACE AND ALOFT WILL BUILD IN SLOWLY...PROVIDING US WITH A DRY SUNNY WEEKEND WITH A GRADUAL WARMING TREND WITH LOW LEVEL WINDS VEERING SOUTHERLY AS THE HIGH MOVES OFFSHORE TO SUPPLEMENT COPIOUS SUNSHINE. HIGHS WILL BE NEAR 80 ON SATURDAY...WITH MOSTLY LOWER 80S SUNDAY AFTER MORNING LOWS IN THE MID TO UPPER 50S. THICKNESSES CONTINUE TO RISE EARLY NEXT WEEK...ALONG WITH INCREASING HUMIDITY AS THE UPPER RIDGE SHIFTS OFFSHORE. OUR NEXT FRONT WILL BE APPROACHING THE MOUNTAINS LATER IN THE DAY TUESDAY. THIS FRONT WILL BE BLOCKED BY THE RIDGING...WHICH WILL NEARLY STALL IT AND FORCE THE FRONT TO ALIGN MORE ALONG A NORTHEAST-SOUTHWEST AXIS ACROSS THE HEART OF THE STATE ON WEDNESDAY. THE ECMWF DOES HOLD RIDGING ALONG THE EAST COAST A LITTLE LONGER...POTENTIALLY DELAYING THE FRONT BY UP TO 24 HOURS. IN LIGHT OF THE SLIGHT TIMING DIFFERENCES...WILL CONTINUE LOW CHANCE POPS FOR CONVECTION IN THE WEST ON TUESDAY... SPREADING TO THE ENTIRE AREA ON WEDNESDAY. HIGHS TUESDAY AND WEDNESDAY WILL BE NEAR 10 DEGREES ABOVE NORMAL AND IT WILL BE RATHER SOUPY WITH HIGHS AROUND 90 AND DEW POINTS FROM 65 TO 70. MORNING MINS WILL MIRROR THE DEW POINT TEMPS...MAINLY IN THE UPPER 60S. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... AS OF 750 PM WEDNESDAY... VFR CONDITIONS WILL PREVAIL THROUGH MIDNIGHT IN ASSOC/W A DRY AIRMASS IN PLACE ACROSS CENTRAL NC. CEILINGS ARE EXPECTED TO DETERIORATE TO MVFR/IFR BY 06-09Z AT ALL TERMINALS AS A WARM FRONT LIFTS NORTHWARD INTO CENTRAL NC. SHOWERS WILL BE POSSIBLE AT ALL TERMINALS BETWEEN 09-15Z THU...BUT ESPECIALLY ACROSS THE NORTHWEST AND TOWARDS THE VA BORDER. THEN...AS A COLD FRONT APPROACHES THE REGION FROM THE WEST...THERE WILL A CHANCE FOR SHOWERS AND THUNDERSTORMS BETWEEN 15-21Z THU...ESPECIALLY ACROSS THE EASTERN PORTIONS OF THE FORECAST AREA (RDU/FAY/RWI) TERMINALS. VFR CONDITIONS WILL RETURN IN THE WAKE OF A COLD FRONTAL PASSAGE FROM WEST-EAST THURSDAY AFTERNOON/EVENING. OUTLOOK: VFR CONDITIONS WILL RULE THROUGH EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...26 LONG TERM...VINCENT AVIATION...KRD/VINCENT

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