Area Forecast Discussion
Issued by NWS Wilmington, 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 250317 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1017 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/...
-- Changed Discussion --
AS OF 1000 PM MONDAY...THE SURFACE COLD FRONT EXTENDS FROM NORTH-CENTRAL GEORGIA ACROSS THE NC/TN BORDER REGION. EAST OF THIS FRONT A SOUTHERLY WIND CONTINUES FROM FLORIDA AND THE BAHAMAS INTO THE EASTERN CAROLINAS. IN THE UPPER LEVELS A STRIPE OF DIFLUENCE EXISTS EXTENDING FROM THE FLORIDA PANHANDLE INTO EAST-CENTRAL NORTH CAROLINA...THE RESULT OF ACCELERATING FLOW INTO THE RIGHT-ENTRANCE REGION OF A 250 MB JET STREAK FROM ARKANSAS INTO NEW YORK STATE. THIS DIVERGENCE HAS SUPPORTED A NARROW BUT PERSISTENT REGION OF RAINFALL (AND EARLIER ELEVATED CONVECTION) ACROSS THE SC PEE DEE REGION INTO LUMBERTON. LATEST HIGH-RES HRRR RUNS SHOW WE SHOULD ENTER A RELATIVE LULL IN PRECIPITATION COVERAGE OVER THE NEXT 2-4 HOURS...BUT INCREASING SOUTHERLY FLOW AND ISENTROPIC LIFT CENTERED ON THE 305K ISENTROPIC SURFACE (~750 MB OR 8000 FEET AGL) SHOULD LEAD TO INCREASING COVERAGE OF RAIN AGAIN LATE TONIGHT INTO THE DAYLIGHT HOURS TUESDAY. ALTHOUGH THE 18Z GFS HAD A FAIRLY FAST EASTWARD MOVEMENT OF THE COLD FRONT OFF THE COAST LATE TONIGHT WITH NW WINDS DEPICTED OVER THE COASTAL WATERS BY 12Z TUE...THE BULK OF THE OTHER GUIDANCE SHOWS A MUCH SLOWER EASTWARD MOVEMENT OF THE BOUNDARY WITH SW WINDS CONTINUING. GIVEN THE CURRENT POSITION OF THE FRONT I AM INCLINED TO BELIEVE THE SLOWER GUIDANCE...AND HAVE ADJUSTED FORECAST WINDS & TEMPS ACCORDINGLY.
-- End Changed Discussion --
&& .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...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM MONDAY...A COLD FRONT IS ANALYZED EXTENDING FROM NORTH-CENTRAL GEORGIA NORTHWARD ACROSS THE NC-TN BORDER REGION. THE BOUNDARY WILL MOVE STEADILY EASTWARD TONIGHT BUT SHOULD REMAIN INLAND FROM THE COAST EVEN AT DAYBREAK TUESDAY. SOUTH-SOUTHWEST WINDS CONTINUE ACROSS THE AREA BRINGING UNSEASONABLY HUMID AIR NORTHWARD FROM FLORIDA AND THE BAHAMAS. AS THIS SUBTROPICAL AIR CROSSES THE CHILLY NEARSHORE OCEAN PATCHY SEA FOG HAS DEVELOPED... MAINLY ALONG THE SC COAST ALTHOUGH PATCHY SEA FOG IS ALSO POSSIBLE ALONG THE BRUNSWICK COUNTY COAST AND POINTS NORTH AS WELL. THE BULK OF THE RAINFALL SHOULD REMAIN INLAND TONIGHT..ALTHOUGH TOWARD DAYBREAK RAIN CHANCES WILL INCREASE FROM SOUTH TO NORTH LEADING UP TO A RATHER SUBSTANTIAL TWO-DAY HEAVY RAINFALL EVENT TUE-WED. SEAS REMAIN QUITE LARGE ESPECIALLY GIVEN THE WIND SPEEDS WE ARE OBSERVING. THIS IS MAINLY DUE TO SOUTHERLY SWELL FROM THE RELATIVELY LONG FETCH OF STRONG WINDS FROM THE BAHAMAS TO THE CAROLINAS OVER THE PAST THREE DAYS. A SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THESE SEAS TONIGHT. 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.
-- End Changed Discussion --
&& .ILM WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR AMZ250-252-254-256.
-- End Changed Discussion --
&& $$ NEAR TERM...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.