Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 080534 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 134 AM EDT WED JUL 8 2015 .SYNOPSIS... THE HEAT AND HUMIDITY WILL BUILD LATE WEEK AND PERSIST INTO NEXT WEEK AS BERMUDA HIGH PRESSURE BUILDS ACROSS THE EASTERN CAROLINAS. A COLD FRONT WILL APPROACH FROM THE NORTH...BUT SHOULD STALL ACROSS NORTHERN NORTH CAROLINA DURING THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1030 PM TUESDAY...CONTINUED WITH NO POPS FOR THE ILM CWA FOR THE REMAINDER OF THIS EVENING THRU THE PRE-DAWN WED HOURS. THIS BASED ON THE LATEST KLTX 88D REFLECTIVITY DISPLAY AND TRENDS. IN ADDITION TO THE RADAR TRENDS...NO UPPER SUPPORT AVBL TO AID IN FIRING UP CONVECTION OVERNIGHT...AND ALSO THE WARM TEMPS DISPLAYED AROUND 600MB WHEN LOOKING AT MODEL SOUNDINGS FOR LOCATIONS ACROSS THE ILM CWA. SHOULD SEE SKIES BECOME MOSTLY CLEAR ACROSS THE FA OVERNIGHT DUE TO THE DEBRIS CONVECTIVE CLOUDS SCOURING OUT. RIGHT NOW...BANKING ON THE DEBRIS CI/CS WELL UPSTREAM TO BECOME LESS OPAQUE AS IT MOVES ACROSS THE FA WITHIN NORTH TO NORTHEAST FLOW IN THE UPPER LEVELS. A WEAK LOW LEVEL SW 20-25 KT JET TO DEVELOP BY LATE THIS EVENING AND SHOULD KEEP WINDS ACTIVE ACROSS THE FA...UP TO 5 MPH INLAND... AND UP TO 10G15MPH ALONG THE IMMEDIATE COASTS. HAVE KEPT FOG ON THE SIDELINE FOR THE TIME BEING. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...DEEP HIGH PRESSURE WILL CONTINUE TO COVER THE CAROLINAS THROUGH THE PERIOD. AT 200 AND 300 MB THE RIDGE WILL BE TO OUR NORTH...AT 500 AND 700 MB THE RIDGE WILL RUN ACROSS SOUTHERN SOUTH CAROLINA...AND AT THE SURFACE THE RIDGE SHOULD BE DISPLACED A LITTLE FARTHER SOUTH ACROSS GEORGIA. ANY UPPER-LEVEL DISTURBANCES WILL BE FORCED ON A PATH WELL NORTH OF THE CAROLINAS. 850 MB TEMPS SHOULD STABILIZE AROUND +19C...PERHAPS APPROACHING +20C INLAND ON THURSDAY. THIS SHOULD TRANSLATE TO HIGHS BOTH DAYS IN THE MID 90S ALONG THE I-95 CORRIDOR...WITH 89-93 NEAR THE COAST. WESTERLY FLOW ACROSS THE APPALACHIANS PLUS HOT TEMPERATURES WILL ENHANCE THE PIEDMONT TROUGH SIGNIFICANTLY. THIS WILL INCREASE THE TYPICAL PRESSURE DROP FROM THE COAST TO THE PIEDMONT REGION OF THE CAROLINAS BY 2-3 MB ABOVE TYPICAL WITH A BERMUDA HIGH OFFSHORE... WITH A CORRESPONDING INCREASE IN AFTERNOON/EVENING SEABREEZE WIND SPEEDS AND OVERNIGHT LOW LEVEL JETTING. FOR THIS REASON I HAVE TRENDED THE FORECAST TOWARD WARMER LOW TEMPS THAN WHAT MOS GUIDANCE IS SUGGESTING. PRECIP CHANCES APPEAR QUITE SLIM THROUGH THE PERIOD. WE`LL HAVE THE SEABREEZE BOUNDARY PLUS THE PIEDMONT TROUGH...BUT THESE FEATURES ALONG DON`T IMPLY MORE THAN ABOUT 10-15% CONVECTIVE COVERAGE. THE 12Z NAM IS GOING ON OUR A LIMB INDICATING AN MCS DIVING EAST-SOUTHEASTWARD ACROSS NORTH CAROLINA WEDNESDAY EVENING...BUT THIS SPECIFIC IDEA IS NOT INDICATED IN THE BULK OF OTHER MODELS AT THIS TIME. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 300 PM TUESDAY...H5 RIDGE WILL SHIFT WEST ACROSS THE AREA FROM THE WESTERN ATLANTIC FRIDAY BECOMING CENTERED OVER THE SOUTH- CENTRAL PLAINS BY SUNDAY. AT THE SURFACE...HIGH PRESSURE OFF THE SOUTHEAST COAST AND INLAND TROUGH WILL PREVAIL. DURING THE WEEKEND THE TROUGH MAY SHIFT OFF THE COAST TEMPORARILY...HOWEVER IN THE MEANTIME THE CHANCE FOR MAINLY DIURNAL CONVECTION WILL EXIST EACH DAY WITH SLIGHTLY HIGHER CHANCES SATURDAY GIVEN THE POSITION OF SURFACE TROUGH AND MORE-SO TUESDAY AS AN UPPER TROUGH IS PROGGED TO EVOLVE ACROSS THE EASTERN UNITED STATES. REGARDING MAX/MIN TEMPS DID NOT STRAY TOO FAR FROM MEX NUMBERS WHICH ARE APPROXIMATELY A CATEGORY ABOVE CLIMO. THE HEAT INDEX WILL LIKELY EXCEED 100F EACH AFTERNOON...BUT SHOULD REMAIN JUST BELOW ADVISORY THRESHOLDS. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...EXPECT VFR THROUGH THE VALID PERIOD WITH POTENTIAL FOR ISOLATED AFTERNOON SHRA/TSRA WITH THE INFLUENCE OF THE SEA BREEZE AND PIEDMONT TROUGH. OVERALL EXPECT VFR TO PREVAIL OVERNIGHT WITH LIGHT SOUTH-SOUTHWEST WINDS...THOUGH WOULD NOT ENTIRELY RULE OUT BRIEF PERIODS OF BR... ESPECIALLY INLAND. HOWEVER...CONFIDENCE IS LOW ATTM. A CANOPY OF MAINLY HIGH CLOUDS WILL PERSIST EARLY THIS MORNING. AFTER DAYBREAK...EXPECT SOUTH-SOUTHWEST WINDS AOB 10 KT WITH GUSTS AROUND 20 KT ALONG THE COAST. ISOLATED TO WIDELY SCATTERED SHRA/TSRA ALONG THE SEABREEZE AND PIEDMONT TROUGH. ANY SHRA/TSRA ACTIVITY WILL TAPER OFF AND WINDS WILL BECOME LIGHT DURING THE LATE EVE. 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 1030 PM TUESDAY...LOOKING AT SW 10 TO 15 KT BECOMING A SOLID SW 15 AFTER MIDNIGHT. THIS WILL CONTINUE THRU THE PRE-DAWN WED HOURS UP TIL DAYBREAK WED. THE MODEST SW WINDS ARE A RESULT OF A LOW LEVEL SW 15 TO 25 KT JET...THAT WILL OCCASIONALLY MIX DOWN TO THE OCEAN SFC. SIGNIFICANT SEAS WILL HANG AROUND 3 FT...OCCASIONALLY UP TO 4 FT ACROSS THE OUTER WATERS OFF CAPE FEAR IF THE HIER WINDS JUST OFF THE DECK ARE ABLE TO MIX DOWN TO THE OCEAN SFC. A BONA FIDE 2 TO 2.5 FOOT SE GROUND SWELL AT 8 TO 9 SECOND PERIODS WILL DOMINATE THE SIGNIFICANT SEAS. THE SPECTRAL DENSITY CHARTS FOR BUOYS ACROSS THE LOCAL WATERS ILLUSTRATE THE HIGHER ENERGY ASSOCIATED WITH THIS SE GROUND SWELL WHEN COMPARED TO LOCALLY PRODUCED WIND DRIVEN WAVES. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...BERMUDA HIGH PRESSURE OFFSHORE AND A PIEDMONT TROUGH INLAND WILL MAINTAIN A SOUTHWESTERLY WIND THROUGH THE PERIOD. AS INLAND TEMPERATURES SOAR WELL INTO THE 90S WE EXPECT A STRONG SEABREEZE CIRCULATION TO DEVELOP BOTH DAYS WITH AFTERNOON/EVENING WIND SPEEDS INCREASING TO 15-20 KT. WIND SPEEDS WILL GRADUALLY DIMINISH LATE AT NIGHT AND VEER MORE WESTERLY. PRECIPITATION POTENTIAL APPEARS QUITE LOW. THE MORNING HOURS MAY HAVE THE BEST CHANCE OF ISOLATED SHOWERS...WITH THE AFTERNOON SEABREEZE SWEEPING UP ANY REMAINING ACTIVITY AND THROWING IT WELL INLAND. SEAS SHOULD AVERAGE 3-5 FEET IN A COMBINATION OF SOUTHEAST 10-SECOND SWELL AND LOCAL 4-SECOND WIND WAVES...HIGHEST DURING THE EVENINGS. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 300 PM TUESDAY...SOUTHWEST FLOW WILL PREVAIL FRIDAY...THEN THE FLOW MAY VEER TO AN OFFSHORE DIRECTION SATURDAY AS A WEAK TROUGH MOVES OFF THE COAST. SOUTHWEST TO SOUTHERLY FLOW WILL BECOME ESTABLISHED ONCE AGAIN DURING SUNDAY. SEAS ARE EXPECTED TO PEAK AROUND 4 FT ACROSS THE OUTER WATERS FRIDAY EVENING...THEN AGAIN BY SUNDAY EVENING. OTHERWISE SEAS 3 FT OR LESS THROUGH THE LONG TERM. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH SHORT TERM...TRA LONG TERM...SRP AVIATION...RJD/SGL

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