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. --
337 FXUS62 KRAH 020804 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 400 AM EDT MON MAY 2 2016 .SYNOPSIS... WARM SOUTHWEST FLOW WILL PREVAIL AHEAD OF A SLOW-MOVING COLD FRONT...AND ASSOCIATED WAVES OF LOW PRESSURE...THAT WILL APPROACH FROM THE NORTHWEST AND CROSS THE MIDDLE ATLANTIC STATES LATE TUE THROUGH EARLY WED. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM SUNDAY... ONE LONE MODEST CELL PASSED OVER THE TRIAD RECENTLY... BUT OTHERWISE THE ISOLATED STRONG TO SEVERE STORMS OVER THE SRN MOUNTAINS AND FOOTHILLS OVER THE LAST SEVERAL HOURS HAVE APPROACHED BUT FAILED TO SURVIVE THE TRIP INTO THE FORECAST AREA DESPITE THE HIGH MOISTURE CONTENT IN PLACE (PW OF 150-175% OF NORMAL). WITH THE LOSS OF HEATING (FOSTERING THE GROWTH IN CINH OVER THE LAST FEW HOURS) AND IN THE ABSENCE OF ANY NOTABLE DYNAMIC FORCING FOR ASCENT (WITH FAIRLY FLAT WSW MID LEVEL FLOW AND NO DISTINCT LOW LEVEL JETTING)... EXPECT LITTLE IN THE WAY OF CONVECTIVE POTENTIAL IN CENTRAL NC FOR THE REMAINDER OF THE NIGHT. HOWEVER... WE SHOULD BE SEEING A SLIGHT RISE IN PW OVERNIGHT ACCORDING TO THE RAP IN CONJUNCTION WITH PASSAGE OF A WAVE TO OUR NORTH ACROSS WV/VA/MD (PARTIALLY RESPONSIBLE FOR THIS EVENING`S SEVERE WEATHER OVER WV/WRN VA)... AND THIS MAY BRUSH OVER THE FAR NORTH-CENTRAL AND NE CWA. IN ADDITION... POOLING OF HIGHER PW OVER THE SE CWA AS IS PROJECTED BY SEVERAL MODELS MAY RESULT IN DEVELOPMENT OF SLOW-MOVING SHOWERS AND ISOLATED STORMS THERE TOWARD MORNING. THE LATEST RAP RUN SUPPORTS THIS WITH A MOISTENING COLUMN LATE TONIGHT AND A FEW HUNDRED J/KG OF LINGERING ELEVATED INSTABILITY. WILL RETAIN CHANCE POPS ACROSS THE FAR N/NE AND OVER THE SE LATER TONIGHT. BASED ON THE WEAK MBE MOVEMENT NOTED BY THE RAP AND DEEP WARM LAYER (LCL-0C NEARING 4 KM)... LOCALLY HEAVY RAIN IS POSSIBLE WITH SLOW-MOVING AND/OR TRAINING CELLS TONIGHT INTO EARLY MON MORNING IN THE SE CWA. MILD LOWS IN THE MID- UPPER 60S. -GIH && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
-- Changed Discussion --
AS OF 400 AM MONDAY... A SHORTWAVE WILL DIVE SOUTH THROUGH THE PLAINS STATES ON TUESDAY AND THEN SWING ACROSS THE DEEP SOUTH TUESDAY NIGHT.... FINALLY GIVING THE STATIONARY FRONT CURRENTLY STRETCHING FROM EAST TX TO THE LOWER GREAT LAKES A KICK TO THE EAST. THE FRONT IS PROGGED TO CROSS NC DURING THE DAY ON TUESDAY...THOUGH THE GFS IS SLIGHTLY FASTER THAN THE ECMWF/NAM IN BRINGING THE FRONT THROUGH CENTRAL NC BY LATE AFTERNOON. THE ECMWF AND NAM FAVOR A FRONTAL PASSAGE LATER IN THE EVENING. DEEP SHEAR IS INCREASINGLY FAVORABLE FOR ORGANIZED CONVECTION TUESDAY AFTERNOON...WITH 40-50KT OF UNIDIRECTIONAL 0-6KM BULK SHEAR AS THE UPPER JET SHIFTS EAST. CAPE IS LITTLE MORE UNCERTAIN GIVEN 1) THE POTENTIAL FOR ONGOING PRECIP OVER WESTERN NC EARLY TUESDAY TO INHIBIT DESTABILIZATION OVER THE WESTERN PIEDMONT AND 2) WESTERLY FLOW AND DEEPER MIXING TO LOWER DEWPOINTS (AGAIN OVER THE WESTERN PIEDMONT). GFS FORECAST SOUNDINGS SUGGEST100- 1500JKG MLCAPE IN THE COASTAL PLAIN. THUS...THE COASTAL PLAIN IS FAVORED FOR STRONGER STORMS TUESDAY AFTERNOON. HIGHS WILL BE IN THE MID AND UPPER 70S. THE SLOWER PASSAGE OF THE COLD FRONT SHOW IN THE ECMWF SUGGESTS THE POTENTIAL FOR LINGERING SHOWERS IN THE COASTAL PLAIN TUESDAY NIGHT AS A WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT WHILE IT APPROACHES THE COAST. LOWS 54-59.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AS OF 400 AM MONDAY... AN OMEGA BLOCK PATTERN IS FORECAST TO DEVELOP FROM MID TO LATE WEEK...WITH A STRONG UPPER RIDGE OVER THE WESTERN CONUS AND AN UPPER LOW DROPPING SLOWLY OUT OF CANADA AND ACROSS THE MID-ATLANTIC STATES AND CAROLINAS. MEDIUM RANGE ENSEMBLES HAVE ADVERTISED THIS UPPER LOW AS 2-3 STD BELOW NORMAL. H10-H85 THICKNESSES DROPPING TO AROUND 1340M BY FRIDAY MORNING SUPPORT THE IDEA OF HIGHS SEVERAL DEGREES BELOW NORMAL...WITH THE COOLEST MEX GUIDANCE INDICATING MID 60S TO LOWER 70S THURS/FRI. MULTIPLE DISTURBANCES WITH THE UPPER LOW AND PERIODIC DCVA COMBINED WITH A POCKET OF COLD AIR ALOFT WILL SUPPORT SHOWERS AND EVEN A FEW ISOLATED STORMS (MAINLY AFTERNOON) THROUGH FRIDAY. THE UPPER LOW SHOULD BEGIN TO FILL AND MOVE EAST BY SATURDAY...WITH RIDGING OVER THE DEEP SOUTH AND NORTHWESTERLY FLOW ACROSS NC. TEMPS SHOULD BEGIN TO CLIMB BACK TO AND ABOVE NORMAL BY THE END OF NEXT WEEKEND.
-- End Changed Discussion --
&& .AVIATION /06Z TUESDAY THROUGH FRIDAY/... AS OF 245 AM MONDAY... AREAS OF STRATUS...IN MOIST/HUMID SSW LOW LEVEL FLOW BELOW A TEMPERATURE INVERSION AROUND 1500 FT...WILL DEVELOP ACROSS CENTRAL NC THIS MORNING...THOUGH COVERAGE AND CEILING HEIGHTS ARE BOTH LIKELY TO BE MORE VARIABLE THAN IN RECENT DAYS. IN ADDITION...A CHANCE OF SHOWERS AND STORMS WILL PERSIST IN A DEEPLY MOIST AND CONDITIONALLY UNSTABLE AIR MASS THIS MORNING...WITH THE RELATIVE MOST LIKELY OCCURRENCE AT KFAY. OTHERWISE...LOW CLOUDS WILL LIFT THROUGH MVFR RANGE AND SCATTER BETWEEN 13-16Z. SUBSEQUENT DIURNAL HEATING OF THE AFOREMENTIONED HUMID AIR MASS WILL DESTABILIZE THE ATMOSPHERE AND SUPPORT SCATTERED TO NUMEROUS STORMS THAT WILL LIKELY DEVELOP ALONG AN APPALACHIAN LEE SURFACE TROUGH AND REMNANT OUTFLOW BOUNDARIES FROM EARLIER CONVECTION - BEST CONVEYED WITH A PROB30 GROUP AT THIS TIME RANGE. THE CHANCE OF SHOWERS AND STORMS WILL AGAIN LINGER OVERNIGHT...AS LOW AMPLITUDE DISTURBANES IN WSW FLOW ALOFT INTERACT WITH A CONTINUED UNSEASONABLY MOIST AND CONDITIONALY UNSTABLE AIR MASS. OUTLOOK: LATE NIGHT-MORNING LOW STRATUS...AND ABOVE AVERAGE CHANCES OF SHOWERS AND STORMS...WILL PERSIST UNTIL A COLD FRONT CROSSES THE MIDDLE ATLANTIC STATES AND MOVES OFFSHORE LATE TUE THROUGH EARLY WED. A POLAR VORTEX WILL MEANWHILE MIGRATE FROM THE ARCTIC CIRCLE TO THE MIDDLE ATLANTIC STATES THROUGH THE END OF THE WEEK...WITH RESULTANT ENHANCED AFTERNOON CLOUDINESS AND SHOWERS/STORMS...AS DIURNAL HEATING OCCURS BENEATH VERY COLD TEMPERATURES ALOFT ATTENDING THE VORTEX. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...26 NEAR TERM...HARTFIELD SHORT TERM...22 LONG TERM...22 AVIATION...26

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