Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 040019 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 819 PM EDT FRI JUL 3 2015 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL PERSIST THROUGH UPCOMING HOLIDAY WEEKEND. THIS WILL CREATE SLIGHTLY ABOVE NORMAL TEMPERATURES...ALONG WITH TYPICAL SUMMERTIME THUNDERSTORM CHANCES EACH AFTERNOON AND EVENING. A FRONT MAY STALL TO OUR NORTH OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM FRIDAY...THE ENTIRE FORECAST AREA IS NOW IN A SLIGHT CHANCE RISK FOR SEVERE THUNDERSTORMS WITH THE GREATEST THREAT BEING FROM WIND DAMAGE...WHICH SPC RATES AT 15 PERCENT. TRENDS SHOW THAT THE STRONGEST CONVECTION NOW UNDERWAY IS ACTUALLY PASSING TO OUR SOUTH AS A SHORT WAVE ROTATES OFFSHORE. TEMPERATURES HAVE BEEN SUPPRESSED OVER THE EASTERN CAROLINAS DUE TO EXTENSIVE CLOUD COVER AND THIS HAS KEPT A DAMPER ON STRONG CONVECTION OVER OUR FORECAST AREA. BREAKS IN THE CLOUD COVER ARE DEVELOPING AND THAT MAY HELP POP SOME STRONGER SHOWERS AND THUNDERSTORMS LATER ON...BUT SO FAR CONVECTION HAS BEEN GENERALLY WEAK WITH LITTLE LIGHTNING AND NO STRONG WINDS. A SEVERE WATCH AREA REMAINS TO OUR S AND SW AND IF CURRENT TRENDS CONTINUE DO NOT EXPECT IT WILL BE EXTENDED UP OUR WAY...ALTHOUGH STRONG CONVECTION PASSING JUST TO OUR SOUTH MAY BRUSH GEORGETOWN COUNTY BEFORE MOVING OFFSHORE THIS AFTERNOON. A BROADLY CYCLONIC YET RELATIVELY FLAT PATTERN WILL PERSIST ALOFT THROUGH THE NEAR TERM...AS WILL THE BERMUDA HIGH/INLAND THERMAL TROUGH PATTERN AT THE SURFACE. TO OUR NORTH A FRONT WILL REMAIN STALLED ALONG THE NC/VA BORDER. COMBINE THESE FACTORS WITH A VERY MOIST AND MODERATELY UNSTABLE AIRMASS AND WE WILL CONTINUE TO SEE THE GOOD CHANCE FOR CONVECTION THIS AFTERNOON AND EVENING. THE USUAL SUSPECTS WILL BE IN PLAY AS FAR AS CONVECTION GOES...DIURNAL HEATING...THE SEA BREEZE FRONT...THE INLAND THERMAL TROUGH...OLD OUTFLOW BOUNDARIES AND UPPER LEVEL DISTURBANCES. THIS LATTER FACTOR WILL BRING THE GREATEST POTENTIAL FOR STRONG CONVECTION AS A SERIES OF SHORT WAVES CYCLE THROUGH THE BASE OF THE UPPER TROUGH. EXACT TIMING OF THESE UPPER FEATURES IS...AS ALWAYS...AN IFFY PROPOSITION...BUT A COMBINATION OF GUIDANCE...AND WATER VAPOR AND RADAR LOOPS SHOWS ONE SUCH SHORT WAVE MOVING THROUGH THIS AFTERNOON...FOLLOWED BY ANOTHER THIS EVENING AND POSSIBLY A THIRD ONE OVERNIGHT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...HOT BUT MOSTLY DRY FOR THE 4TH OF JULY...COOLER AND MORE UNSETTLED WEATHER WILL FOLLOW FOR THE 2ND HALF OF THE WKND. EASTERN CONUS TROUGH WILL PERSIST THIS WKND...BUT AS THE TROUGH AXIS REMAINS WEST OF THE LOCAL AREA...SUBTLE SHORTWAVE RIDGING WILL EXIST OVER THE CWA SATURDAY. THIS WILL COMBINE WITH SUBSIDENCE BEHIND A DEPARTING SHORTWAVE FROM OVERNIGHT FRIDAY NIGHT...TO PRODUCE A HOT AND MOSTLY SUNNY AND DRY DAY. TEMPS WILL WARM INTO THE LOW-TO-MID 90S AWAY FROM THE BEACHES...WITH UPR 80S EXPECTED ALONG THE COAST. VERY DRY-MID LEVELS WILL PRECLUDE MUCH IN THE WAY OF CONVECTION EVEN AS AFTN CU BUILDS...SO BUILDUP WILL LIKELY REMAIN PRETTY SHALLOW. THE SEA BREEZE...AND ESPECIALLY PIEDMONT TROUGH...MAY BE ABLE TO OVERCOME THIS DRY AIR ENOUGH TO PRODUCE A FEW SHOWERS/TSTMS SATURDAY EVENING...BUT FOR THE MOST PART FIREWORKS FESTIVITIES SATURDAY NIGHT SHOULD BE CLEAR AND DRY WITH LOWS SATURDAY NIGHT DROPPING INTO THE LOW 70S WELL INLAND...MID 70S AT THE COAST. A MORE TYPICAL SUMMERTIME DAY ON TAP FOR SUNDAY WITH MORE SCATTERED DIURNAL CONVECTION. SHORTWAVE WILL TRY TO CLOSE OFF ACROSS THE TN VLY...AND WHILE THIS WILL STAY MOSTLY WEST OF OUR AREA...SUBTLE HEIGHT FALLS ARE EXPECTED ALONG WITH INCREASING MOISTURE AND BETTER PVA. THIS WILL CREATE MORE CLOUD COVER AND BETTER AFTN CONVECTION CHANCES...ALONG WITH KEEPING TEMPS A FEW DEGREES COOLER...WITH MOST PLACES HOVERING 1-2 DEGREES EITHER SIDE OF 90. CONTINUING HEIGHT FALLS AND SHORTWAVE ENERGY MAY PERSIST CONVECTION WELL INTO SUNDAY NIGHT...ALTHOUGH WITH DECREASED COVERAGE...AND MINS SUNDAY NIGHT WILL FALL TO SEASONABLE LEVELS AROUND 70...SEVERAL DEGREES WARMER AT THE COAST. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 3 AM FRIDAY...MONDAY AND TUESDAY STILL HAVE SOME INGREDIENTS IN PLACE THAT COULD KEEP THE WEATHER SOMEWHAT UNSETTLED ESPECIALLY BY JULY STANDARDS. MID LEVEL TROUGH REMAINS JUST TO OUR WEST ALBEIT IN A WEAKENING STATE WHILE AT THE SURFACE A PIEDMONT TROUGH WORKS IN TANDEM WITH SEA BREEZE AND OUTFLOW BOUNDARIES TO INITIATE CONVECTION. DEEP SWRLY FLOW COULD BRING MORE CLOUDS THAN WE TYPICALLY SEE THIS TIME OF YEAR. THE NET EFFECT OF THE CLOUDINESS WILL BE TO TEMPER DAYTIME HIGHS SLIGHTLY WHILE BOLSTERING NIGHTTIME LOWS. THE MID LEVEL FEATURE WEAKENS FOR THE REMAINDER OF THE PERIOD AND WE SHOULD TRANSITION BACK TO A REGIME WHERE MID LEVEL FLOW IS VERY WEAK AND SURFACE MESOSCALE FEATURES ACT AS THE LONE CONVECTIVE INITIATORS. TEMPERATURES SHOULD BE CLOSE TO SEASONABLE. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...POTENTIAL FOR MVFR/IFR CIGS THROUGH THE OVERNIGHT HOURS WITH VCSH LATE...OTHERWISE EXPECT VFR WITH VCSH/VCTS POSSIBLE SATURDAY AFTERNOON. LATEST RADAR DEPICTS THE LAST BATCH OF LIGHT SHOWERS MOVING NORTHEASTWARD OFFSHORE...NO LONGER AFFECTING ANY OF THE TERMINALS. FEW/SCT LOW CIGS WILL MOVE ACROSS THE AREA WHICH COULD CREATE BRIEF PERIODS OF MVFR/POSSIBLE IFR OVERNIGHT...HOWEVER CONFIDENCE IS LOW. OTHERWISE EXPECT VFR WITH SOUTHWEST WINDS AOB 12 KTS. WILL MENTION SOME OF THE GUIDANCE IS SUGGESTING REDEVELOPMENT OF SHRA OVERNIGHT...AND THUS HAVE INTRODUCED VCSH. ON SATURDAY...VFR WILL PREVAIL WITH WEST-SOUTHWEST WINDS AOB 12 KTS AND GUSTS NEAR 20 KTS. ISOLATED VCSH/VCTS POSSIBLE IN THE AFTERNOON HOURS. EXTENDED OUTLOOK...CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY...WITH BRIEF PERIODS OF MVFR/IFR POSSIBLE. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM FRIDAY...BERMUDA HIGH/INLAND TROUGH PATTERN WILL PERSIST THROUGH THE NEAR TERM...WITH SW WINDS INCREASING FROM THE PRESENT 10 TO 15 KTS TO THE 15 TO 20 KT RANGE FOR AMZ252-256 THIS AFTERNOON AND PERSISTING TONIGHT. SEAS WILL BUILD TO 3 TO 5 FT FOR THOSE WATERS. THE EXCEPTION WILL BE FOR AMZ250...WHERE WINDS WILL INCREASE TO 20 TO 25 KTS AND SEAS WILL BUILD TO 4 TO 6 FT. A SMALL CRAFT ADVISORY IS IN EFFECT TONIGHT FOR THAT ZONE...WITH EXERCISE CAUTION HEADLINES OUT FOR THE REMAINDER. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE DURING THE SHORT TERM...WITH SW WINDS EXPECTED THROUGH THE WEEKEND. ALTHOUGH DIRECTION WILL VARY LITTLE...SPEEDS SATURDAY WILL INCREASE TO 15-20 KTS...HIGHEST LATE AFTN/EVE AS THE GRADIENT TIGHTENS THANKS TO THE SHARPENING PIEDMONT TROUGH. WINDS WILL BE 10- 15 KTS SUNDAY AS THE GRADIENT REMAINS A BIT WEAKER. ADDITIONALLY...NEAR SHORE WINDS WILL BACK MORE TO THE SOUTH WITH THE SEA BREEZE SATURDAY AFTN AND EVE BEFORE RETURNING TO A SW DIRECTION SATURDAY NIGHT. WAVE HEIGHTS WILL REMAIN 3-4 FT BOTH DAYS...WITH A SW WIND WAVE PREDOMINANT IN THE SPECTRUM LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 3 AM FRIDAY...INLAND SURFACE TROUGHINESS APPEARS RATHER WEAK MONDAY AND TUESDAY LIKELY WASHED OUT IN PART BY THE FLOW ASSOCIATED WITH THE FRONT THAT HAD BEEN STALLED TO OUR NORTH DURING THE SHORT TERM PERIOD. SEAS WILL RELAX SOMEWHAT NOT ONLY DUE TO THE DOWN TICK IN WIND SPEED BUT ALSO THE DECREASED AREAL COVERAGE OF THE FETCH ALONG THE EAST COAST. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR AMZ250-252. && $$ NEAR TERM...REK SHORT TERM...JDW LONG TERM...MBB AVIATION...SGL

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