Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 300224 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1024 PM EDT WED JUL 29 2015 .SYNOPSIS... A WEAK TROUGH OF LOW PRESSURE ACROSS THE EAST CENTRAL CAROLINAS WILL LINGER INTO THURSDAY AS MEANDERING WEAK LOW PRESSURE REMAINS OFF THE SOUTHEAST COAST. A WEAK COLD FRONT WILL MOVE INTO THE AREA FRIDAY AND STALL DURING THE WEEKEND BEFORE DISSIPATING MONDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 1000 PM WEDNESDAY...THIS UPDATE CONCERNED MORE-SO WITH OVERNIGHT WINDS. A SFC LOW TO MEANDER ALONG A STALLED FRONT JUST OFFSHORE FROM THE FORECAST AREA. CONVECTION NO LONGER AN EVENING THREAT AND HAVE PULLED THE POPS. STILL THERE IS A CONCERN FOR NOCTURNAL ATL SHOWERS TO DEVELOP AND POSSIBLY AND BRIEFLY MOVE ONSHORE AND SIDE-SWIPE THE LAND AREAS OF CAPE FEAR...AND CAPE ROMAINE. STILL NOT ALL THAT CONFIDENT AND THEREFORE HAVE CONTINUED TO REFRAIN FROM PLACING THAT LOW CHANCE POP. STILL THOUGH...I CONTINUE TO MENTION ITS REMOTE POSSIBILITY IN THE DISCUSSION HERE. VERY LITTLE TWEAKING NEEDED TO THE UPDATED ATM PARAMETERS 3 HRS AGO. PREVIOUS......................................................... AS OF 700 PM WEDNESDAY...JUST TOO WARM IN THE MID-LEVELS... BETWEEN 550MB AND 350MB...RESULTING IN NO REAL VERTICAL DEVELOPMENT WITH THIS AFTN AND EVENINGS CU FIELD. A FEW MODERATE CU PRODUCED VERY BRIEF LIGHT TO MODERATE SHOWERS AS EVIDENCED BY THE KLTX 88D OUTPUT. WITH THE DAYS HEATING OVERWITH...ANY FUTURE DEVELOPMENT OF CONVECTION OVER LAND IS DOUBTFUL FOR THIS EVENING AND OVERNIGHT. HOWEVER...OVER THE ADJACENT ATL WATERS...MODEL SOUNDINGS INDICATE A RATHER DEEP NE WIND THRU THE ATM COLUMN FOR THE OVERNIGHT PERIOD. THIS FLOW DIRECTION SHOULD KEEP ANY NOCTURNAL ATLANTIC PCPN PARALLEL TO THE CAROLINAS COASTLINES. THE POSSIBLE EXCEPTION WILL BE LAND AREAS INVOLVING CAPE FEAR...AND ALSO CAPE ROMAINE WHERE ISOLATED SHRA MAY CROSS OVER. FOR NOW WILL HOLD OFF WITH THIS POSSIBLE SHRA EFFECTS FROM OFF THE ATL...BUT WILL AGAIN MAKE A DECISION AT THE NEXT UPDATE WHETHER TO INCLUDE THIS ISOLATED PCPN. WEIRD RESULTANT WIND BOUNDARY ORIENTATION AS IT PUSHED INLAND LATE THIS AFTN AND EVENING. DID CAUSE SOME RE- ADJUSTING TO THE HOURLY DEWPOINTS ACROSS THE FA. BASICALLY LOOKING AT LOWS TONIGHT IN THE 70 TO 75 DEGREE RANGE...HIGHEST AT THE IMMEDIATE COAST. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 315 PM WEDNESDAY...A WEAK COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA...THEN STALL NEAR THE COAST FRIDAY PRIOR TO BECOMING INCREASINGLY DIFFUSE. A WEAK AREA OF LOW PRESSURE FAR OFF THE COAST WILL LIFT NORTHEAST THROUGH FRIDAY. MEANWHILE ALOFT...THE SUBTROPICAL RIDGE REMAINS ANCHORED ACROSS TX/NM RESULTING IN A CONTINUATION OF WEAK MID/UPPER TROFFING OVER THE EASTERN UNITED STATES. THE MID/UPPER TROF IS IN A LITTLE BETTER SHAPE FRIDAY AND WITH THE AFOREMENTIONED FRONT IN THE VICINITY THE POTENTIAL FOR SCATTERED SHOWERS AND TSTMS WILL EXIST. THE PRECIPITABLE WATER IS ALSO QUITE HIGH THURSDAY...AND WHILE WE COULD SEE SOME STORMS DEVELOP ALONG THE WEAK INLAND TROF AND SEA BREEZE BOUNDARIES COVERAGE IS EXPECTED TO BE LIMITED. BETTER INSTABILITY WILL DEVELOP AND BE AVAILABLE DURING FRIDAY. MAV NUMBERS LOOK REASONABLE THROUGH THE SHORT TERM PERIOD WITH HIGHS/LOWS WITHIN A COUPLE DEGREES OF CLIMO. ALSO REGARDING MINOR OCEAN OVERWASH...THE TIDE LEVELS MAY GET CLOSE TO MINOR COASTAL FLOODING AT WRIGHTSVILLE BEACH AND SPRINGMAID PIER WITH HIGH TIDE THURSDAY AND FRIDAY EVENING. IT LOOKS LIKE THRESHOLDS WILL BE MET AT THE WILMINGTON RIVERFRONT TIDE GAUGE AS WELL THURSDAY NIGHT AND AGAIN FRIDAY NIGHT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 315 PM WEDNESDAY...BIGGEST CHALLENGE THIS PERIOD INVOLVES A DISSIPATING COLD FRONT WHICH WILL BE IN THE VICINITY THIS WKND. GUIDANCE CONTINUES TO BACK OFF ON PRECIP CHANCES SAT AND SUN AS THE FRONT PUSHES OFFSHORE AND WASHES OUT. THIS IS LIKELY DUE TO THE LONGWAVE TROUGH AXIS BEING PROGGED TO PUSH OFF THE SE COAST...FILTERING COOLER AND DRIER AIR INTO THE REGION. THE GFS IS THE MOST AGGRESSIVE WITH THIS DRYING...WHILE THE ECMWF IS MOST AGGRESSIVE WITH THE COOLING...A CLEAR DISCONNECT. WHILE THIS FRONT IS TECHNICALLY OF POLAR ORIGIN (VERY NEAT TO SEE THE TERM POLAR FRONT USED BY WPC IN THE SOUTHEAST IN JULY)...THERE APPEARS TO BE LITTLE TRUE COOL ADVECTION WITH IT. ADDITIONALLY...THE GFS ENSEMBLE MEAN MAINTAINS THE LONGWAVE TROUGH AXIS TO THE WEST...WHICH WOULD SUPPORT THE FRONT DISSIPATING ALONG THE COAST AS OPPOSED TO WELL OFFSHORE. WILL SIDE WITH WPC AND KEEP THE FRONT ALONG THE COAST SAT/SUN...BUT WILL WALK POP DOWN DUE TO DRYING ALOFT. STILL SCT SHOWERS/AND TSTMS POSSIBLE THIS WKND WITH TEMPS AROUND OR SLIGHTLY BELOW CLIMO. LONGWAVE TROUGH ERODES NEXT WEEK AS THE RIDGE ACROSS TEXAS EXPANDS TO THE NE. THIS WILL BRING A RETURN TO THE BERMUDA HIGH PRESSURE BECOMING THE DOMINANT FEATURE WITH 850MB TEMPS AND 500MB HEIGHTS CLIMBING EACH DAY. THESE FEATURES WILL CREATE TEMPS RISING TO WELL ABOVE SEASONABLE VALUES ONCE AGAIN BY THE MIDDLE OF NEXT WEEK...ALONG WITH CLIMO OR BELOW POP CHANCES. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... AS OF 23Z...SATELLITE AND RADAR SHOWING NOT MUCH HAPPENING ACROSS THE TERMINALS THIS EVENING WITH A HIGH DEGREE OF CONFIDENCE WE WILL BE VFR UNTIL AROUND 09Z WHEN SOME FOG CAN DEVELOP ACROSS THE INLAND TERMINALS AS LOW LEVEL MOISTURE AND DECOUPLED ATMOSPHERE WILL LEND ITSELF TO RIPE CONDITIONS ACROSS KLBT AND KFLO. HIGH CLOUDS WILL COVER THE REGION THROUGHOUT THE OVERNIGHT PERIOD AND INTO THURSDAY AS WELL. VFR CONDITIONS TO CONTINUE THURSDAY AFTER 15Z WITH MAINLY A LIGHT E TO SE WIND. NEXT CONCERN WILL BE AN APPROACHING FRONTAL BOUNDARY FROM THE WEST THAT WILL INCREASE CHANCES OF PRECIPITATION ACROSS THE AREA AFTER 00Z. MODELS SHOW REGION BETWEEN FRONTAL BOUNDARY TO THE WEST AND DEVELOPING LOW PRESSURE TO OUR SE WHICH SHOULD PASS WELL OFFSHORE WITH MINIMAL AVIATION IMPACTS. EXTENDED OUTLOOK...PREDOMINANTLY VFR THROUGH THE PERIOD WITH A SLIGHT CHANCE AFTERNOON SHRA/TSRA. BEST CHANCE SHRA/TSRA FRIDAY AND SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM WEDNESDAY...LOOKING AT THE LATEST TRENDING OBS AND A 1ST LOOK AT MODEL DATA ACROSS THE AREA WATERS...BOTH INDICATE THE SFC PRESSURE PATTERN OVERNIGHT TO YIELD A BIT FURTHER BACK OF THE WIND DIRECTIONS TO A NNE-ENE RANGE. THIS DUE TO THE POSITIONING OF THE SFC LOW OFFSHORE ALONG THE STALLED SFC BOUNDARY. SFC PG REMAINS ON THE RELAXED SIDE...WITH 10 TO OCCASIONALLY 15 KT. SIGNIFICANT SEAS TO CONTINUE IN THE 2 TO 4 FOOT RANGE...WITH PERIODS AT 4 TO 6 SECONDS...STILL A WIND WAVE DOMINATING THE SIGNIFICANT SEAS. PREVIOUS.......................................................... AS OF 700 PM WEDNESDAY...SFC PRESSURE PATTERN OVER THE AREA WATERS TO YIELD A ENE-E WIND FIELD. THE SFC PRESSURE GRADIENT TO YIELD 10-15 KT WITH A FEW GUSTS UP TO 20 KT POSSIBLE. THIS DUE TO A STALLED FRONTAL BOUNDARY OFFSHORE AND ORIENTED PARALLEL TO THE SE U.S. COASTLINE. A FEW -SHRA/TSRA TO DEVELOP IN THE VICINITY OF THIS BOUNDARY AND TRACK TO THE SW...AND FOR THE MOST PART REMAINING PARALLEL TO THE CAROLINA COASTLINES. A FEW COULD COULD DRIFT ACROSS CAPE FEAR AND/OR CAPE ROMAINE TOWARDS DAYBREAK THU. SIGNIFICANT SEAS WILL RUN 2 TO 4 FT...WITH THE 4 FOOTERS MOST COMMON FROM SURF CITY TO THE VICINITY OF CAPE FEAR. DOMINANT PERIODS WILL RUN 4 TO 6 SECONDS INDICATIVE OF SHORT PERIOD WIND DRIVEN WAVES PRIMARILY AFFECTING THE LOCAL WATERS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 315 PM WEDNESDAY...WEAK LOW PRESSURE OFF THE COAST THU ALONG WITH A WEAK INLAND TROUGH WILL ONLY SUPPORT LIGHT WINDS ACROSS THE WATERS. THE LOW IS EXPECTED TO LIFT NORTHEAST OFF THE OUTER BANKS DURING FRIDAY AS A WEAK COLD FRONT SHIFTS TOWARD THE COAST AND STALLS. AS A RESULT...LIGHT WINDS WILL PERSIST INTO FRIDAY THEN BECOME SOUTHERLY AND INCREASE ONLY SLIGHTLY. SEAS ARE EXPECTED TO BE AROUND 3 FT OR LESS THROUGH THE BULK OF THE PERIOD. LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 315 PM WEDNESDAY...DISSIPATING FRONT WILL BE IN THE VICINITY THROUGH THE WEEKEND BEFORE WASHING OUT ENTIRELY LATE SUNDAY INTO MONDAY. STILL SOME UNCERTAINTY INTO THIS FRONTAL PLACEMENT...BUT EXPECT IT TO STALL AND FALL APART JUST INLAND FROM THE WATERS. THIS WILL LEAVE A WEAK GRADIENT ACROSS THE WATERS...WITH SW FLOW BECOMING PREDOMINANT ONCE AGAIN AS BERMUDA HIGH RE-ASSERTS ITSELF. WINDS SATURDAY WILL BE LIGHT AND VARIABLE...GRADUALLY BECOMING SW AROUND 10 KTS BY SUNDAY AND PERSISTING INTO MONDAY. SEAS WILL BE 2-3 FT SATURDAY WHEN WINDS ARE THE LIGHTEST...BECOMING 3-4 FT FOR SUNDAY AND MONDAY ON THE GREATER WINDS AND SLIGHTLY INCREASED GROUND SWELL. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...DCH NEAR TERM...DCH SHORT TERM...SRP LONG TERM...JDW AVIATION...MAC

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