Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 092349 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 749 PM EDT WED JUL 9 2014 .SYNOPSIS... A COLD FRONT WILL STALL OVER THE REGION LATE THURSDAY INTO EARLY SATURDAY...BRINGING GOOD CHANCES FOR THUNDERSTORMS. THIS FRONT WILL DISSIPATE LATE IN THE WEEKEND WITH A RETURN TO TYPICAL SUMMERTIME CONDITIONS BY EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 730 PM WEDNESDAY...HOT SOUTHWEST FLOW AROUND THE WESTERN EDGE OF BERMUDA HIGH PRESSURE BROUGHT FLORENCE ITS FIRST 100 DEGREE READING OF THE YEAR TODAY. TEMPERATURES IN THE MID TO UPPER 90S WERE WIDESPREAD AWAY FROM THE BEACHES. ALL THIS HEAT INLAND MIXED DRY DOWN FROM ALOFT INLAND...LIMITING CONVECTIVE COVERAGE AS SURFACE-BASED CAPE DROPPED TO ONLY A FEW HUNDRED J/KG. LATE TONIGHT MOISTURE WILL INCREASE THROUGH A DEEP LAYER OF THE ATMOSPHERE VIA CONTINUED SOUTHWEST FLOW FROM THE SURFACE UP THROUGH 25000 FEET. DESPITE MODEST LAPSE RATES ALOFT THIS INCREASE IN MOISTURE SHOULD PRODUCE ELEVATED CAPE ON THE ORDER OF 500-1000 J/KG BEFORE DAYBREAK. I HAVE TRIMMED BACK POPS SHARPLY THROUGH THE EVENING HOURS BUT WILL STILL SHOW 20-30 PERCENT CHANCES FOR A SHOWER OR T-STORM LATE TONIGHT...ESPECIALLY INLAND WHERE THE MID-LEVEL MOISTURE RETURN SHOULD OCCUR FIRST. FOR THE PAST TWO NIGHTS GFS AND NAM MOS LOWS HAVE BEEN PRETTY ABYSMAL. BIAS CORRECTION BASED ON THE PAST TWO NIGHTS WAS USED TO MODIFY TONIGHT`S FORECAST LOWS...ANTICIPATED TO RANGE FROM THE MID 70S INLAND TO AROUND 80 ON THE BEACHES. PREVIOUS DISCUSSION FROM 230 PM FOLLOWS... FINE CU FIELD BUILDING RIGHT ALONG SEA BREEZE BOUNDARY AS IT MAKES ITS WAY INLAND THROUGH THIS AFTERNOON...LEAVING TIP OF CAPE FEAR THE SUNNIEST SPOT. HRRR MODEL FORECAST HOLDING WELL SO FAR AS BROKEN LINE OF CONVECTION STREAMING FROM SOUTHWEST TO NORTHEAST JUST WEST OF FORECAST AREA. MODELS SHOWED THIS LINE DIMINISHING AS IT PUSHES EASTWARD THROUGH EARLY THIS EVENING. WILL KEEP POPS AS IS WITH POSSIBILITY OF AN ISOLATED SHWR ALONG SEA BREEZE AND CHC POPS OVER INLAND COUNTIES MAINLY LATER TODAY. DEW POINT TEMPS WILL HOLD IN THE MID 60S INLAND THROUGH THIS AFTERNOON AND CLOSER TO 70 ALONG THE COAST IN A CONTINUED SOUTHWEST FLOW OF WARM AND MOIST AIR AT THE SURFACE AROUND BERMUDA HIGH. OVERALL VERY WARM DAY WITH SPOTTY CU FIELD LEAVING A GOOD DEAL OF SUNSHINE AND TEMPS INTO THE 90S MOST PLACES. LATEST MOISTURE PROFILES KEEP VERY DRY MID LEVELS THROUGH MUCH OF TONIGHT AS MID TO UPPER RIDGE HOLDS ON FOR ONE LAST DAY. CONVECTIVE PARAMETERS BECOME MORE FAVORABLE THIS EVENING BUT SUPPORT FOR CONVECTION WILL DIMINISH THROUGH THIS EVENING AS HEATING OF THE DAY CUTS OFF. THE MAIN FOCUS FOR CONVECTION WILL LIE MAINLY TO OUR WEST AS PIEDMONT TROUGH AND AN APPROACHING COLD FRONT DRIVE MUCH OF THE CONVECTIVE ACTIVITY. A DEEPENING UPPER TROUGH OVER EASTERN CONUS WILL PUSH EAST PROVIDING MUCH GREATER SUPPORT FOR CONVECTION AND THIS MAY REACH FAR ENOUGH INTO THE CAROLINAS BY THIS EVENING TO TRIGGER SOME SHWRS/TSTMS WHICH MAY REACH INTO WESTERN REACHES OF FORECAST AREA BY THIS EVENING THIS COLD FRONT WILL PUSH EAST WITH PLENTY OF MOISTURE POOLING AHEAD OF IT AND INCREASED UPPER LEVEL SUPPORT HEADING INTO THURS. MAY SEE SOME SHWRS/TSTMS AROUND OVERNIGHT INTO EARLY THURS BUT MAIN ACTIVITY WILL COME LATER IN THE DAY. ANOTHER WARM NIGHT AHEAD WITH TEMPS DROPPING BUT REMAINING IN THE 70S.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
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AS OF 3 PM WEDNESDAY...AN UPPER LEVEL TROUGH AND SURFACE COLD FRONT WILL BE SHIFTING INTO THE AREA. AT THE SURFACE THIS FRONT WILL STALL AND ABOVE THE SURFACE PRECIPITABLE WATERS WILL INCREASE TO 2 PLUS INCHES. THE FLOW ALOFT WILL PARALLEL THE FRONT AND THE 850 TO 700 MB WINDS WILL BE AT 10 TO 15 KNOTS. EVEN HIGHER THE UPPER LEVEL FORCING FROM THE 300 MB JET WILL INCREASE SYNOPTIC SCALE LIFT. SO THE POSSIBILITY OF HEAVY RAIN OVER THE AREA THURSDAY AFTERNOON THROUGH FRIDAY MIDDAY CONTINUE TO BE HIGH. BY FRIDAY MIDDAY THE SYNOPTIC SCALE VORTICITY HAS SHIFTED OFFSHORE AND IT WILL DRAG THE DEEPER MOISTURE WITH IT. EXPECT THE CHANCES FOR THE HEAVY RAIN TO DIMINISHED AT THIS TIME. MAXIMUM TEMPERATURES WILL REACH THE LOWER 90S ON THURSDAY IF THE CONVECTION HOLD OFF AND CLOUDS AND RAIN DO NOT COOL THE ATMOSPHERE TO QUICKLY. EXPECT HIGHS TO BE EVEN LOWER WITH CLOUDS AND RAIN KEEP THE HIGHS AT BAY AND REACHING INTO THE UPPER 80S. LOW TEMPERATURES WILL BE IN THE MID 70S THURSDAY NIGHT AND THE LOWER 70S FRIDAY NIGHT.
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&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...REMAINS OF COLD FRONT STILL SHOWING UP STALLED ACROSS THE AREA ON SATURDAY. BETWEEN SOME UNCERTAINTY AS TO WHERE IT STALLS PAIRED WITH MODEL DISAGREEMENT REGARDING WHICH SIDE OF THE BOUNDARY IS FAVORED FOR PRECIP WILL STICK WITH PREVIOUS AREA-WIDE 40-ISH POP. THE BOUNDARY WASHES OUT ON SUNDAY AND A VERY WEAK PIEDMONT TROUGH MAY BE DEVELOPING. ITS STILL HARD TO SHOW ANY PARTICULAR FAVORED AREA FOR POPS BUT WILL SHOW A SMALL DOWNWARD TREND DUE TO SOME MID LEVEL DRYING. MONDAY SHOULD OFFER SEASONABLE TEMPERATURES AND A SEASONABLE DISTRIBUTION OF DIURNAL CONVECTION AS THE AREA FINDS ITSELF BETWEEN A VERY WEAK UPPER RIDGE OVER FL AND AN UNSEASONABLY LARGE/STRONG VORTEX DROPPING INTO THE GREAT LAKES. TUESDAY AND WEDNESDAY FEATURE A RETURN OF THE PIEDMONT TROUGH AND A SLIGHT VEERING OF THE MID LEVEL FLOW FROM THE AFOREMENTIONED UPPER LOW. RAINFALL CHANCES SHOULD INCREASE JUST SLIGHTLY WHILE TEMPS REMAIN NEAR NORMAL. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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AS OF 00Z...PATCHY AREAS OF FOG OVERNIGHT COULD CREATE BRIEF-MVFR INLAND...AND INCREASING CHANCES FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED ON THURSDAY POSSIBLY CREATING MVFR/IFR ESPECIALLY IN HEAVIER DOWNPOURS. OTHERWISE EXPECT VFR. VFR PREVAILS THIS EVENING WITH SOUTHWEST WINDS AOB 10 KTS...AND HIGHER GUSTS ALONG THE COAST...WHICH ARE EXPECTED TO SUBSIDE WITHIN THE NEXT FEW HOURS. RADAR IMAGERY OVERALL QUIET ACROSS THE AREA WITH A FEW ISOLATED SHOWERS JUST TO THE WEST/NORTHWEST...WHICH COULD POSSIBLY MOVE NEAR THE INLAND SITES. HOWEVER DO NOT ANTICIPATE ANY RESTRICTIONS. PATCHY AREAS OF FOG OVERNIGHT COULD CREATE BRIEF MVFR INLAND INTO THE EARLY MORNING AS WELL BUT CONFIDENCE REMAINS LOW. ON THURSDAY...EXPECT INCREASING CLOUDS AND CHANCES FOR SHRA/TSRA THROUGHOUT THE DAY. HEAVY DOWNPOURS ARE EXPECTED GIVEN THE FAVORABLE ENVIRONMENT...THUS ANTICIPATE PERIODS OF MVFR/IFR. AS FOR WINDS...EXPECT SOUTH-SOUTHWEST WINDS AOB 10 KTS INLAND AND UP TO AROUND 15 KTS WITH GUSTS ALONG THE COAST. EXTENDED OUTLOOK...A FRONT STALLS OVER THE REGION WITH A DECENT CHANCE FOR CONVECTION THROUGH SATURDAY...MAINLY IN THE AFTERNOON. MORE SHOWERS AND STORMS ARE POSSIBLE MONDAY. BRIEF IFR CONDITIONS ARE POSSIBLE IN THE HEAVIER SHOWERS AND STORMS. OTHERWISE EXPECT VFR.
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&& .MARINE...
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NEAR TERM /THROUGH TONIGHT/... AS OF 730 PM WEDNESDAY...MUCH LIKE LAST NIGHT WINDS ARE GUSTING 22-26 KNOTS AT OBSERVATION SITES ALONG THE BEACHES...COURTESY OF THE AFTERNOON SEABREEZE PLUS A TIGHT PRESSURE GRADIENT ALONG THE WESTERN EDGE OF THE BERMUDA HIGH. A LOW LEVEL JET SHOULD STRENGTHEN OVERHEAD AGAIN THIS EVENING WITH 1000 FOOT WINDS INCREASING TO 25-30 KNOTS...BUT SHOULD ALSO DIE AWAY FASTER THAN IT DID LAST NIGHT. AVERAGE WIND SPEEDS TONIGHT SHOULD BE 15-20 KT. SEAS ARE AROUND 4 FEET AT THE NEARSHORE WRIGHTSVILLE BEACH BUOY...WITH LITTLE CHANGE EXPECTED OVERNIGHT. PREVIOUS DISCUSSION FROM 230 PM FOLLOWS... SOUTHWESTERLY FLOW WILL CONTINUE OVER THE WATERS THROUGH TONIGHT BETWEEN HIGH PRESSURE OVER THE WESTERN ATLANTIC AND TROUGH OF LOW PRESSURE INLAND. SEAS WILL REMAIN BETWEEN 2 AND 4 FT AS GRADIENT WEAKENS THROUGH THE NIGHT LEAVING WINDS OF 15 KTS OR LESS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...AS A COLD FRONT APPROACHES THE COAST LATE THURSDAY THE SOUTHWEST WINDS WILL INCREASE TO 15 KNOTS BUT THE WINDS WILL WEAKEN AS THE FRONTAL BOUNDARY STALLS AT THE COAST AND THE PRESSURE GRADIENT WEAKENS FRIDAY. SEAS ARE EXPECTED TO BE AROUND 3 FEET ON THURSDAY BUT WILL SLOWLY DIMINISH TO 2 FEET BY FRIDAY NIGHT IN RESPONSE TO THE WINDS. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 PM WEDNESDAY...LIGHT WINDS EXPECTED ON SATURDAY WITH A WEAKENING FRONT STALLED ACROSS THE AREA. THIS BOUNDARY WILL CAST A SMALL DEGREE OF UNCERTAINTY WITH RESPECT TO WIND DIRECTION BUT SOUTHERLY FLOW GENERALLY EXPECTED TO BE PREDOMINANT. THIS BOUNDARY WASHES OUT BY SUNDAY AS A WEAK PIEDMONT TROUGH DEVELOPS. THIS MAY BE GOOD FOR ABOUT A 5KT/1FT INCREASE IN CONDITIONS. A SIMILAR OR EVEN LARGER INCREASE IN WINDS AND SEAS MAY BE SLATED FOR MONDAY. BROAD CYCLONIC CURVATURE AROUND A LARGE STORM NORTH OF THE GREAT LAKES RESPONSIBLE FOR TIGHTENING THE GRADIENT LOCALLY. HEADLINES OR EVEN AND ADVISORY APPEAR POSSIBLE.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RGZ/TRA SHORT TERM...HAWKINS LONG TERM...MBB AVIATION...SGL

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