Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 180517 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 115 AM EDT MON AUG 18 2014 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA FROM THE NORTH MONDAY AND TUESDAY BEFORE STALLING OVER THE AREA AND REMAINING THROUGH FRIDAY. THE FRONT COULD DROP SOUTH OF THE AREA FOR THE WEEKEND. HEAT AND HUMIDITY WILL REMAIN OVER THE AREA THROUGH THURSDAY BEFORE TEMPERATURES RETURN TO MORE SEASONABLE VALUES LATE THIS WEEK INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 10:30 PM SUNDAY...STILL LOOKS LIKE A DRY OVERNIGHT PERIOD BASED ON LATEST GUIDANCE AND RADAR LOOPS. HAVE TWEAKED GRIDDED DATABASE FOR THE NEAR TERM BUT THIS HAS MADE NO DIFFERENCE TO THE ACTUAL FORECAST. PREVIOUS DISCUSSION FROM THIS AFTERNOON FOLLOWS: THE MID LEVEL FLOW WILL REMAIN WEST TO EAST THROUGH THE AFTERNOON AND OVERNIGHT HOURS. AT THE SURFACE...BERMUDA HIGH PRESSURE WILL CONTINUE TO DOMINATE. IT NOW APPEARS THE SHORTWAVE MOVING ACROSS KENTUCKY WILL SLOW DOWN SOMEWHAT AS IT TRAVERSES THE APPALACHIANS AND MAY BE MORE OF A PLAYER FOR POPS MONDAY. I HAVE REMOVED ANY MENTION OF ACTIVITY FOR THE AFTERNOON AND OVERNIGHT HOURS. VISIBLE SATELLITE IMAGERY IS SHOWING LITTLE CUMULUS DEVELOPMENT AS FAR AS SEA BREEZE ACTIVITY IS CONCERNED. OVERNIGHT LOWS AGAIN LOOK TO BE SLIGHTLY ABOVE GUIDANCE WITH MIDDLE 70S ALONG THE COASTAL AREAS AND LOWER 70S EXTREME WEST/NORTHWEST. FINALLY WILL PROBABLY SEE LESS COVERAGE OF FOG AS WE STAY VOID OF RAINFALL. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...HOT AND HUMID CONDITIONS ARE ON TAP FOR THE BEGINNING OF THE WEEK. CHANCES FOR CONVECTION WILL INCREASE FOR MONDAY AND TUESDAY THOUGH AS A SHORTWAVE TROUGH MOVES SLOWLY THROUGH TO THE NORTH...RESULTING IN HEIGHT FALLS OVER THE FA THAT LINGER THROUGH TUESDAY. IN ADDITION...THE UPPER FEATURE CARVES OUT A SURFACE TROUGH OVER THE AREA WITH A WEAK COLD FRONT AND LOW PRESSURE AREA TO THE NORTH. ALL IN ALL...EXPECTED SCATTERED SHOWERS AND THUNDERSTORMS BOTH DAYS WITH COVERAGE TO BE THE GREATEST DURING THE AFTERNOON AND EVENING HOURS. POPS WILL BE HIGHER NORTHERN AREAS EACH DAY DUE TO THE PROXIMITY OF THE SURFACE AND UPPER FEATURES. HIGHS WILL BE IN THE LOW TO MID 90S BOTH DAYS WITH LOWS IN THE LOW TO MID 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...LATEST MODELS HAVE CAST SOME UNCERTAINTY REGARDING THE PREVIOUSLY ANTICIPATED VERY HOT AND HUMID MID WEEK PERIOD. ON WED AND THURSDAY A BROAD LOW AMPLITUDE UPPER RIDGE WILL BE SPANNING ACROSS MUCH OF THE WESTERN ATLANTIC INTO THE BAHAMAS AND GOMEX AS WELL AS THE SOUTHEASTERN U.S. THIS WAS SUPPOSED TO LEAD TO HOT AND HUMID CONDITIONS LOCALLY AND MINIMAL PRECIP CHANCES. COMPLICATING FACTOR HOWEVER IS THAT SOME GUIDANCE INCLUDING THE LATEST WRF AND GFS IS THAT SOME ENERGY MAY CREST THE RIDGE AND MAKE IT THIS FAR SOUTH AND DRIVE A COLD FRONT VERY NEAR THE REGION. THE RESULTING ADDED CLOUD COVER AND POSSIBLE CONVECTIVE COVERAGE COULD TEMPER DAYTIME HIGHS. THIS IS NOW PROGGED TO OCCUR AS SOON AS WEDNESDAY AND IS THE CURRENT FORECAST IN THE WPC MANUAL PROGS. INTERESTINGLY MOST MOS GUIDANCE STILL SHOWS UNSEASONABLE WARMTH ESPECIALLY ON THURSDAY. THIS SEEMS PLAUSIBLE AS THE FRONT WILL LIKELY NOT HAVE MUCH OF A TEMPERATURE GRADIENT BUT THERE IS STILL THE POSSIBILITY OF THE AFOREMENTIONED CONCERN OF ADDITIONAL CLOUD COVER. AT THIS POINT WILL NOT MAKE MANY CHANGES IN LIGHT OF THE UNCERTAINTY. FOR THE REMAINDER OF THE PERIOD THE BOUNDARY WILL REMAIN IN PLACE OR EVEN SINK SOUTHWARD A BIT AS THE MID AND UPPER RIDGE INCREASES IN AMPLITUDE AND RETROGRADES WESTWARD ALLOWING FOR STRONGER NW FLOW LOCALLY. THIS SHOULD FURTHER TEMPER WHATEVER EARLY PERIOD HEAT PANS OUT ESPECIALLY OVER THE WEEKEND WHEN A RETURN OF NORMAL TEMPS IS EXPECTED. WHAT REMAINS TO BE SEEN IS WHETHER THE LATE PERIOD NORTHWEST FLOW WILL HAVE SUFFICIENT ENERGY TO BRING SOME RIDGE- TOPPING ROUNDS OF STORMS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...EXPECT PATCHY FOG TO DEVELOP. GREATEST CONFIDENCE IS AT THE INLAND TERMINALS AND/OR CRE WHERE WINDS WILL BE LIGHTEST. INCREASING VFR LEVEL CLOUDS SHOULD AID IN PREVENTING ANY IFR OR LOWER VISIBILITIES. TOWARDS MORNING THERE MAY BE ISOLATED...IE. LOW CHANCE...FOR CONVECTION AT KLBT/KFLO. ALTHOUGH CLOUD COVER WILL GREATLY AFFECT WARMING TEMPERATURE AFTER SUNRISE...CONVECTION SHOULD FIRE BETWEEN 16-19Z. BEST CHANCE FOR TSRA WILL BE AT KCRE/KMYR WHERE WESTERLY STEERING FLOW WILL SPREAD ACTIVITY ALONG A PINNED SEA BREEZE BACK TOWARDS THE COAST. TSRA WILL ALSO BE MORE LIKELY AT KLBT WHERE GREATER LIFT IS EXPECTED DUE TO ITS CLOSER PROXIMITY TO AN AREA OF LOW PRESSURE PASSING BY TO THE NORTH. DRIER AIR TO MOVE INTO THE MID/UPPER LEVELS DURING LATE THIS AFTERNOON AND EVENING...SUGGESTING CONVECTION WILL DECREASE/BECOME MORE ISOLATED IN COVERAGE. EXTENDED OUTLOOK...CHC AFTERNOON/EVENING SHRA/TSRA THROUGH THE PERIOD. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE EARLY MORNING HOURS EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 10:30 PM SUNDAY...LATEST OBS CONTINUE TO SHOW SW WINDS OF 10 TO 15 KTS WITH 2 TO 3 FT SEAS. FORECAST REMAINS UNCHANGED. STILL EXPECTING A FURTHER GRADUAL INCREASE IN SEAS BY DAYBREAK. PREVIOUS DISCUSSION FOLLOWS: SOUTHWEST FLOW WILL CONTINUE TO INCREASE VERY GRADUALLY THROUGH THE AFTERNOON AND OVERNIGHT HOURS. THEY SHOULD PEAK AT 15 KNOTS BY MORNING UP FROM THE CURRENT TEN KNOTS OR SO. SEAS WILL INCREASE SLOWLY AS WELL FROM TWO FEET AT THE MOMENT TO 2-4 FEET WITH THE FOUR FOOTERS BEING FEW AND FAR BETWEEN. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...EXPECT SW WINDS INVOF 15 KT THROUGH THE FORECAST PERIOD AS HIGH PRESSURE SHIFTS TO THE EAST AND A SURFACE TROUGH DEVELOPS OVER THE AREA. WINDS COULD APPROACH 20 KT TUESDAY AFTERNOON AND EVENING WHEN THE PRESSURE GRADIENT LOOKS TO BE THE TIGHTEST. OUTSIDE OF THE POTENTIAL FOR 5 FOOTERS AT 20 NM TUESDAY AFTERNOON AND EVENING...SEAS LOOK TO REMAIN 4 FT OR LESS. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...HIGH PRESSURE SPANNING A VAST AMOUNT OF OCEAN ALONG ROUGHLY 28N ALL THE WAY FROM THE WEST/CENTRAL ATLANTIC TO THE GOMEX. A SMALL WEAKNESS ALONG THE FL PENINSULA EXTENDING N INTO THE CAROLINAS AS A BETTER DEFINED PIEDMONT TROUGH. LOCALLY THIS KEEPS SOUTHWESTERLY WINDS QUITE LIGHT AND IN THE ABSENCE OF APPRECIABLE SWELL ENERGY WAVES CAPPED AT 2-3FT. SOME TROUGHINESS ALOFT BY THURSDAY MAY WEAKEN THE ANTECEDENT RIDGE AND A WEST-TO- EAST ORIENTED FRONTAL BOUNDARY MAY SAG INTO THE CAROLINAS. WIND SPEEDS WILL REMAIN VERY LIGHT EVEN FOR AUGUST AND THE DIRECTION MAY VEER SLIGHTLY TO WESTERLY. NOT SURE YET IF THE FRONT GETS FAR ENOUGH SOUTH FOR SOME ZONES TO SEE A N OR NE FLOW YET DURING THE PERIOD BUT IT IS CERTAINLY POSSIBLE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RAN NEAR TERM...REK/SHK SHORT TERM...RAN LONG TERM...MBB AVIATION...DCH/MRR

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