Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Text Only | 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 242341 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 641 PM EST MON NOV 24 2014 .SYNOPSIS... MILD TEMPERATURES AND UNSETTLED WEATHER IS EXPECTED TONIGHT AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA TUESDAY MORNING. COOL AND WET CONDITIONS ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY AS DEEPENING LOW PRESSURE MOVES NORTH ALONG THE FRONT STALLED OFFSHORE. SKIES WILL CLEAR OUT ON THANKSGIVING DAY...WITH TEMPERATURES RUNNING SEVERAL DEGREES BELOW NORMAL INTO THE COMING WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 645 PM MONDAY...UPDATES IN THE NEAR-TERM CENTER ON A SIZABLE AREA OF MODERATE RAIN WITH EMBEDDED THUNDERSTORMS MOVING NORTHEASTWARD ACROSS EASTERN SOUTH CAROLINA. THIS ACTIVITY SHOULD SPREAD NORTHWARD ALONG THE INTERSTATE 95 CORRIDOR THIS EVENING DROPPING A GENERAL QUARTER-INCH OF RAIN WITH HIGHER TOTALS ALONG THE TRACK OF THE EMBEDDED CONVECTIVE ELEMENTS. SEVERE WEATHER POTENTIAL APPEARS ALMOST ZERO AS INSTABILITY IS VERY ELEVATED WITH NO SURFACE- BASED INSTABILITY TO WORK WITH. POPS HAVE BEEN INCREASED TO 100 PERCENT ALONG THE AHEAD OF THIS FEATURE...WITH LESSER CHANGES ALONG THE COAST WHERE THIS BATCH OF PRECIPITATION SHOULD REMAIN LARGELY TOO FAR WEST FOR ANY DIRECT IMPACTS. ALSO I HAVE ADDED PATCHY FOG ALONG THE COAST MAINLY SOUTH OF SUNSET BEACH AS SEA FOG HAS DEVELOPED ACROSS THE NEARSHORE WATERS AND IS ADVECTING ONSHORE IN THE SOUTH-SOUTHWEST WINDS. AS WIND DIRECTIONS VEER MORE WESTERLY WITH TIME VISIBILITIES SHOULD GRADUALLY IMPROVE ALONG THE COAST LATE THIS EVENING AND ESPECIALLY AFTER MIDNIGHT. NO SIGNIFICANT CHANGES HAVE BEEN MADE WITH REGARDS TO OTHER PARTS OF THE FORECAST. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... WARM AND MOIST AIR WILL CONTINUE TO STREAM INTO THE COASTAL CAROLINAS HELPING TO BRING TEMPS UP INTO THE MID 70S MOST PLACES THIS AFTERNOON. CLOUDS CONTINUED TO COVER THE ENTIRE FORECAST AREA WITH BEST COVERAGE OF SHOWERS THROUGH THE AFTERNOON HOURS LOCATED OVER INLAND AREAS. THERE WAS A VERY SHARP GRADIENT OF CLOUD TO NO CLOUD COVER JUST BEYOND OUR CWA. MOIST SW FLOW WILL CONTINUE THROUGH TONIGHT...BUT DRY AIR THROUGH THE MID LEVELS AND DECENT CAP WITH LAPSE RATES NOT LOOKING TOO GOOD WILL KEEP STRONGER CONVECTION MORE ISOLATED IF AT ALL. LLJ UP TO 45 TO 50 KTS THROUGH THIS EVENING WITH MORE UNIDIRECTIONAL SHEAR OVERALL. EXPECT ONLY A FEW CONVECTIVE CELLS WITH HEAVIER RAIN OR LIGHTNING THROUGH THIS EVE. SOUNDINGS CONTINUE TO DRY OUT THE COLUMN THROUGH THE EVENING HOURS AND EXPECT COVERAGE TO DIMINISH INTO THE EVENING HOURS WITH SHWRS MOVING RAPIDLY OFF TO THE NORTHEAST WITH A SW STORM MOTION UP TO 40S KTS. COLD FRONT WILL PROGRESS THROUGH THE AREA OVERNIGHT. BEST CONVERGENCE WILL ALIGN ITSELF WITH AND JUST AHEAD OF THE FRONT WHICH SHOULD PROGRESS THROUGH THE CWA FROM WEST TO EAST AFTER MIDNIGHT HEADING TOWARD THE COAST BY MORNING. THE BEST UPPER LEVEL SUPPORT WILL ROUND THE BASE OF THE UPPER LEVEL TROUGH REMAINING WELL WEST OF LOCAL AREA BUT MODELS DO SHOW SOME ENHANCED LIFT ALIGNED FROM SW TO NE AS COLD FRONT CROSSES THE AREA AFTER MIDNIGHT. WILL INCREASE COVERAGE AND POPS AT THIS TIME. TEMPS WILL REMAIN WELL ABOVE NORMAL WITH WINDS JUST BEGINNING TO VEER AROUND TO THE WEST BY DAYBREAK IN WESTERN ZONES. DO NOT EXPECT CAA TO AFFECT OVERNIGHT LOWS AND THEREFORE TEMPS WILL REMAIN IN THE 60S FOR MOST OF THE NIGHT WITH READINGS BETWEEN 55 AND 60 MOST PLACES BY DAYBREAK. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...INCREASED CONFIDENCE IN SUBSTANTIAL RAINFALL ESPECIALLY ALONG THE COAST THROUGH THE PERIOD. COLD FRONT PUSHES OFF THE COAST AND DECELERATES EARLY TUESDAY. THE COLD AIR ADVECTION AND DEEP MOISTURE BOTH LAG BEHIND AND THERE SHOULD BE JUST ENOUGH STRUNG OUT VORTICITY AND LOW LEVEL CONVERGENCE FOR OCCASIONAL LIGHT RAIN THROUGH THE DAY. TEMPS WILL BE FAIRLY CLOSE TO CLIMO DESPITE THE WIDESPREAD CLOUDS AND RAINFALL. SEVERAL INGREDIENTS THEN COME TOGETHER TUESDAY NIGHT FOR SOME RATHER IMPRESSIVE DYNAMICS AND POTENTIAL HEAVY RAIN. MID LEVEL IMPULSE CURRENTLY OVER SRN TX SWINGS THROUGH THE TROUGH AND GIVES IT A WEAK NEGATIVE TILT. SURFACE LOW DEVELOPS ALONG THE FRONT OFFSHORE. STRONG SSWRLY LOW LEVEL JET DEVELOPS IN ASSOC WITH THIS WAVE WHILE WEAK ISALLOBARIC COMPONENT TURNS FLOW INTO THE LOW WEST OF IT...I.E. OVER LANDMASS. THIS RESULTS IN AN IMPRESSIVE THERMAL GRADIENT...850MB TEMPS NEAR 15C JUST OFF COAST AND DOWN TO 2 C OVER WRN ZONES BY 12Z WED. THE RESULTING LOW LEVEL FRONTOGENESIS IS SOME OF THE STRONGEST I`VE SEEN IN A WHILE...WITH THE GFS FORECASTING VALUES OF 100-200 UNITS. IT IS ALSO TOUGH TO RULE OUT A NARROW ZONE OF CONDITIONAL SYMMETRIC INSTABILITY DEVELOPING RIGHT OVER THE IMMEDIATE (MAINLY NC) COAST AND ADJACENT WATERS. DURING THE OVERNIGHT HOURS THIS LOW LEVEL FORCING MAY EVEN COUPLE WITH DEEPER ASCENT FROM THE DEVELOPING UPPER JET CONFIGURATION AS THE RIGHT ENTRANCE OF A 190KT UPPER JET MOVES INTO PA. IN FACT GFS CROSS SECTIONS FOR A TIME SHOW ASCENT CLEAR THROUGH THE DEPTH OF THE COLUMN. WITH AT LEAST SOME CONNECTION TO GOMEX MOISTURE THIS SETUP COULD EASILY YIELD 2-2.5 INCHES OF RAINFALL ALONG THE IMMEDIATE COAST BEFORE THE RAIN TAPERS OFF MIDDAY WEDNESDAY OR WEDNESDAY AFTERNOON. THE BULK OF THE RAIN WILL FALL OVERNIGHT TUESDAY TO PERHAPS AS LATE AS DAYBREAK WED. THEREAFTER THE DEEP MOISTURE AND UPPER FORCING SHIFT OFFSHORE. LIGHTER RAIN WED MORNING THEN GIVES WAY TO A DRYING TREND AS COLD AIR ADVECTION BEGINS CRANKING UP BY 18Z. WEDNESDAY AFTERNOON HIGHS WILL NOT BE MUCH HIGHER THAN TUESDAY NIGHT LOWS. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...MID LEVEL TROUGHING OVER THE SOUTHEAST AT THE START OF THE PERIOD WILL LIFT NORTHEAST FRI WITH PROGRESSIVE FLOW DEVELOPING FOR THE WEEKEND. MID LEVEL TROUGH HELPS PUSH REMAINS OF DRY COLD FRONT THROUGH EARLY FRI WITH HIGH PRESSURE BUILDING IN FOR THE WEEKEND. PROGRESSIVE FLOW QUICKLY PUSHES THE CENTER OF THE HIGH OFFSHORE WITH RETURN FLOW DEVELOPING AS EARLY AS MIDDAY SAT. DEEP DRY WESTERLY FLOW WILL HELP KEEP THE REGION DRY THROUGH THE END OF THE PERIOD. TEMPERATURES BELOW CLIMO FOR THE FIRST HALF OF THE PERIOD WILL START A STEADY CLIMB BACK TO CLIMO EARLY NEXT WEEK AS HIGH MOVES FARTHER OFF THE COAST AND RETURN FLOW STRENGTHENS. LATE IN THE PERIOD A WEAK BACKDOOR COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE AREA. LATEST GFS KEEPS THIS FEATURE NORTH WHILE ECMWF PUSHES IT SOUTH. WILL FAVOR THE ECMWF SOLUTION...WHICH IS FAVORED BY WPC...FOR NOW BUT CONFIDENCE IS LOW. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 00Z...CONDITIONS WILL DETERIORATE TONIGHT AS IFR/LIFR STRATUS AND VSBYS PLAGUE OUR COASTAL TERMINALS. IFR CONDITIONS HAVE PREVAILED FOR MUCH OF THE DAY AT THE COASTAL SITES...INCLUDING SOME PATCHY SEA FOG AT KCRE/KMYR. ALTHOUGH OBS MAY FLUCTUATE BETWEEN MVFR/IFR THIS EVENING...EXPECT MORE PERSISTENT IFR/LIFR CONDITIONS AFTER MIDNIGHT AS MOIST SOUTHWEST FLOW AND PATCHY -RA CONTINUE AHEAD OF A COLD FRONT. MEANWHILE...KFLO/KLBT WILL REMAIN VFR FOR MUCH OF TONIGHT...EXCEPT FOR TEMPO MVFR/IFR CONDITIONS ASSOCIATED WITH EMBEDDED SHRA ACTIVITY AHEAD OF THE FRONT. IFR STRATUS COULD EXPAND INLAND TOWARD DAYBREAK...BUT CONFIDENCE IS LOW/MODERATE THAT CIGS WILL STAY BELOW 1KFT AT KFLO/KLBT EARLY TUE. PCPN COVERAGE SHOULD INCREASE INTO TUE MORNING AS THE FRONT MOVES THROUGH THE CWA. THE BOUNDARY BECOMES POORLY DEFINED AS IT REACHES OUR AREA...SO A PERIOD OF LIGHT/VRBL WINDS IS POSSIBLE WHILE WINDS SHIFT FROM SOUTHWEST TO NORTHWEST. DEEP MOISTURE AND UPPER SUPPORT WILL CONTINUE TO PROMOTE -RA THROUGH MUCH OF THE DAY EVEN BEHIND THE FRONT. EXPECT IFR CIGS TO PREVAIL ALONG THE COAST AND MVFR INLAND... WITH VSBY RESTRICTIONS POSSIBLE IN HEAVIER RAINFALL. EXTENDED OUTLOOK...RAIN WITH MVFR/IFR CIGS WILL PERSIST INTO WED AFTN...ESPECIALLY ALONG THE COAST. EXPECT GUSTY WINDS LATE TUE/EARLY WED...IN ADDITION TO HEAVIER PCPN THAT WILL REDUCE VSBYS TO MVFR/IFR AT TIMES. VFR LATE WED THROUGH SAT. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 645 PM MONDAY...BIGGEST CHANGE IN THE NEAR-TERM WAS TO ADD PATCHY FOG NEARSHORE. BOTH MYRTLE BEACH AIRPORTS HAVE HAD PERIODS OF VERY LOW VISIBILITIES OVER THE PAST COUPLE HOURS AS WAVES OF SEA FOG HAVE ROLLED ONSHORE. THIS SEA FOG IS LIKELY AFFECTING THE WATERS SOUTH OF SUNSET BEACH ALONG THE UPPER SOUTH CAROLINA COAST THE WORST AS SEA SURFACE TEMPERATURES ARE COLDEST HERE...AND THE SOUTH-SOUTHWEST WIND HAS A RELATIVELY LONG FETCH LENGTH ACROSS THE COLDER WATER. ALONG THE BRUNSWICK COUNTY COAST AND NORTH OF CAPE FEAR FOG IS NOT IMPOSSIBLE...JUST LESS LIKELY...DUE TO SHORTER FETCH LENGTH AND WATER TEMPERATURES A GOOD 3-6 DEGREES WARMER THAN ALONG THE SC COAST. OTHERWISE WIND/SEA FORECASTS LOOK GOOD AND NO SIGNIFICANT CHANGES ARE REQUIRED. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH TONIGHT. GRADIENT WILL RELAX THROUGH TONIGHT WITH WINDS DIMINISHING AS COLD FRONT PROGRESSES EAST REACHING CLOSE TO THE COAST BY DAYBREAK TUES MORNING. MODERATE S-SW FLOW WILL KEEP SEAS ELEVATED IN THE 4 TO 8 FT RANGE THROUGH EARLY THIS EVENING...BUT AS WINDS DIMINISH THROUGH THE NIGHT...SEAS WILL BEGIN TO SUBSIDE. WNA SHOWS WINDS DIMINISHING TO LESS THAN 15 KTS AS THEY BEGIN TO SLOWLY VEER AROUND AS FRONT APPROACHES THE COAST HEADING INTO TUES MORNING. THIS WILL ALLOW SEAS TO SLOWLY SUBSIDE DOWN TO 4 TO 6 FT BY MORNING. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...COLD FRONT PUSHES THROUGH EARLY TUESDAY WITH LITTLE FANFARE OTHER THAN A WIND SHIFT BUT A VERY DYNAMIC SETUP ALOFT WILL LEAD TO A RAPID DECAY IN CONDITIONS TUESDAY NIGHT. LIGHT OFFSHORE WINDS MUCH OF THE DAY TUESDAY AS THE FRONT SLOWS. STRONG SYSTEM SWINGING OUT OF SOUTHERN TEXAS TO THEN CAUSE FAIRLY RAPID PRESSURE FALLS ALONG THE BOUNDARY TUESDAY NIGHT INTO WEDNESDAY. AS THIS LOW CRANKS UP AND MOVES BY CONDITIONS SHOULD RAMP UP TO SMALL CRAFT ADVISORY LEVELS. BY WEDNESDAY MORNING THE STILL DEEPENING LOW ACCELERATES OFF TO OUR NORTH AND EAST. STRONG OFFSHORE WINDS STILL LIKELY WORTHY OF AN ADVISORY LIKELY CONTINUE IN THE ENSUING COLD SURGE AND SEAS WILL SIMILARLY BE HESITANT TO FALL BELOW CRITERIA BEFORE WEDNESDAY NIGHT. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM MONDAY...PINCHED GRADIENT THU INTO FRI WILL MAINTAIN OFFSHORE FLOW IN THE 15 TO 20 KT RANGE INTO FRI. GRADIENT WEAKENS MIDDAY FRI FOLLOWING PASSAGE OF REMAINS OF DRY COLD FRONT. NORTH TO NORTHWEST FLOW ON FRI WILL WEAKEN AS SURFACE HIGH BUILDS INTO THE REGION...MOVING OVERHEAD LATE IN THE DAY. WINDS WILL BECOME LIGHT AND VARIABLE LATER FRI AND SAT AS THE SURFACE RIDGE AXIS LINGERS IN THE REGION. SEAS 2 TO 4 FT THU INTO FRI WILL DROP TO 2 FT OR LESS AS WINDS BECOME LIGHT AND VARIABLE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...RGZ/TRA SHORT TERM...MBB LONG TERM...III AVIATION...BJR

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