Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 221725 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 125 PM EDT MON SEP 22 2014 .SYNOPSIS...
-- Changed Discussion --
AN UPPER LEVEL LOW WILL BRING RAIN TO MOST OF THE AREA TONIGHT. A STALLED COLD FRONT OFFSHORE WILL WAVER BACK TOWARDS THE COAST DURING THE MIDDLE AND LATTER PART OF THE WEEK...BRINGING GOOD CHANCES FOR RAIN AND BELOW NORMAL TEMPERATURES. A WARMING AND DRYING TREND IS EXPECTED DURING THE WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 130 PM MONDAY...THE COLD FRONT CONTINUES TO DROP SOUTH AS DEWPOINTS ARE NOW IN THE UPPER 50S ACROSS MOST AREAS. ANY SHOWERS ASSOCIATED WITH THE BOUNDARY HAVE DISSIPATED FOR THE MOST PART AT LEAST FOR THE MOMENT. THIS LULL IN ACTIVITY WILL CONTINUE FOR THE NEXT FEW HOURS BEFORE THE DEEP MID LEVEL TROUGH ACROSS THE APPALACHIANS DROPS FURTHER SOUTH AND CLOSES OFF. SEVERAL FACTORS SEEM TO HAVE COME TOGETHER TO FORECAST A WET OVERNIGHT PERIOD FOR THE EASTERN THIRD OF THE CWA. FIRST THERE IS A DECENT PLUME OF MOISTURE EMANATING FROM THE GULF OF MEXICO VIA WATER VAPOR. SECOND...THE OMEGA WILL COME IN SEVERAL FORMS THROUGH A DEEP LAYER. STARTING AT THE LOWEST LEVELS...SOME MODEST ISENTROPIC LIFT EXISTS IN THE 209-300K LAYER. MOVING UP...SOME MID LEVEL FRONTOGENESIS EVIDENT IN THE 700-500MB LAYER. DIFLUENCE EXISTS AT THE 500MB LAYER AND FINALLY...A STRONG JET AT 300MB WILL MOVE UP THE COAST AND THE FAVORABLE REGIONS WILL MOVE ACROSS THE COASTAL AREAS. LONG STORY SHORT...I HAVE INCREASED POPS TO LIKELY FOR THESE AREAS. QPF AMOUNTS MAY ECLIPSE ONE HALF INCH ESPECIALLY SOUTHERN AND EXTREME COASTAL AREAS BUT WILL OTHERWISE END UP BETWEEN ONE TENTH INLAND TO ONE HALF ELSEWHERE. I HAVE MADE A FEW ADJUSTMENTS FOR THE AFTERNOON TEMPERATURES TO ADDRESS THE CLOUD COVER COOLED READINGS BUT OVERNIGHT LOWS REMAIN ON TRACK FOR LOWER 60S ALONG THE COAST TO UPPER 50S NORTHWEST.
-- End Changed Discussion --
&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...THE FIRST FULL OF DAY OF FALL ON TUESDAY BEGINS WITH COLD FRONT POSITIONED JUST OFFSHORE...AS LARGE CANADIAN HIGH PRESSURE CENTERED OVER THE OH VLY RIDGES DOWN INTO THE CAROLINAS. ALTHOUGH THIS FRONT WILL BE OFFSHORE...THERE IS SOME UNCERTAINTY INTO JUST HOW FAR FROM THE COAST IT WILL GET BEFORE STALLING. THE UPPER ENERGY DRIVING THIS FRONT WILL WEAKEN AND BECOME BROAD OVERHEAD...STALLING AS A GREAT LAKES AREA RIDGE BLOSSOMS FROM THE SOUTHWEST. THIS CREATES A DIFFICULT FORECAST BECAUSE...ALTHOUGH MOST OF THE AREA WILL BE DRY TUESDAY...THE BROAD LOW OVERHEAD WILL INTERACT WITH THE SURFACE BOUNDARY TO CAUSE WIDESPREAD RAIN SHOWERS LURKING JUST OFF THE COAST...POSSIBLY ALONG THE COAST. WINDS THROUGH THE LOWEST 600MB OF THE COLUMN WILL VEER TO THE E/NE...LIKELY DRIVING THE BOUNDARY /COASTAL TROUGH/ BACK TOWARDS SHORE. THIS CREATES INCREASING SHOWER CHANCES ON WEDNESDAY...HIGHEST POP NEAR THE COAST. ATTM IT LOOKS LIKE THE HEAVIEST RAIN WILL REMAIN JUST OFFSHORE WITH ONLY LIGHT RAIN ANTICIPATED WITHIN THE CWA. HOWEVER...THIS WILL NEED TO BE MONITORED CLOSELY AS A VERY SHARP GRADIENT WILL EXIST BETWEEN HEAVY RAIN AND JUST LIGHT SHOWERS. TEMPS BOTH TUESDAY AND WEDNESDAY WILL BE BELOW NORMAL FOR LATE SEPTEMBER...WITH HIGHS IN THE MID/UPR 70S BOTH DAYS. HOWEVER...TUESDAY WILL HAVE NOTICEABLY MORE SUNSHINE THAN WEDNESDAY. LOWS TUESDAY NIGHT WILL FEATURE WIDESPREAD 50S...WITH SOME LOW 50S POSSIBLE WEST OF I-95. MINS WEDNESDAY NIGHT WILL BE SEVERAL DEGREES WARMER THANKS TO INCREASING ONSHORE FLOW. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...VERY UNSETTLED THE FIRST HALF OF THE PERIOD AS THE PATTERN TAKES ON MORE OF A WINTER-LIKE FEEL...BUT IMPROVEMENTS ARE EXPECTED FOR THE WEEKEND. DIFFUSE UPPER LOW OVERHEAD THURSDAY WILL WORK IN TANDEM WITH A COASTAL TROUGH JUST OFFSHORE TO PRODUCE WIDESPREAD CLOUDS AND RAIN THURSDAY/FRIDAY. STILL UNCERTAINTY EXISTING IN EXACTLY HOW THE PATTERN WILL EVOLVE LATE-WEEK...AS THERE WILL BE A VERY SHARP GRADIENT BETWEEN EXTREMELY HIGH PWATS LURKING JUST OFFSHORE...AND MUCH MORE TYPICAL PWATS TOWARDS I-95. THE DIFFERENCE IS DUE TO THE COASTAL TROUGH WHICH WILL BE SLOWLY ADVECTING WESTWARD ON DEEP EASTERLY FLOW...PUSHING THE BETTER RAIN CHANCES TOWARDS THE COAST. WPC GRAPHICS SHOW THIS GRADIENT WELL...WITH ABOUT 4 INCHES OF QPF CENTERED JUST OFF THE CAPE FEAR COAST...BUT LESS THAN ONE-QUARTER INCH IN THE WESTERN ZONES. THE ECMWF IS ONE OF THE MORE PESSIMISTIC MODELS...BUT IS FAVORED BY WPC...AND THE TREND HAS BEEN FOR A MORE UNSETTLED THU/FRI PERIOD. WILL BUMP POP TO MDT CHC FOR LATE WEEK AND CONTINUE WITH HIGHS BELOW CLIMO BUT LOWS SLIGHTLY ABOVE. THE COASTAL TROUGH WILL BEGIN TO ERODE SATURDAY AS RIDGING FINALLY DISPLACES THE UPPER TROUGH...BECOMING MORE PRONOUNCED AT THE END OF THE PERIOD. THIS SUGGESTS DRYING FOR THE WEEKEND...ESPECIALLY AT THE MID-LEVELS...AND RAIN CHANCES WILL TAKE A DECIDEDLY DOWNWARD TURN DURING THE WKND...ALTHOUGH IT MAY BE SLOW. IMPROVING CONDITIONS WILL ALSO ALLOW TEMPS TO RECOVER TO SEASONABLE NORMS. && .AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
AS OF 18Z...A COLD FRONT WILL CONTINUE TO DROP SOUTHWARD...WITH NORTH NORTHEAST WINDS AT ALL TERMINALS. PATCHY LIGHT RAIN MAY BE REPLACED WITH HEAVIER CONVECTION...MAINLY ALONG THE EXTREME SOUTHEASTERN PORTION OF THE CWA...POSSIBLY AFFECTING THE MYRTLES. PREDOMINATELY MVFR CONDITIONS IN THE SHOWERS. TONIGHT...ACTIVITY DIMINISHING WITH CONTINUED NORTHEAST FLOW. THE NAM IS VERY PESSIMISTIC WITH REGARD TO CEILINGS...BRINGING EVERYONE DOWN TO IFR. FELL THIS IS WAY OVERDONE AT THE JUNCTION...BUT KEEP AN OPEN MIND. TUESDAY...A LOW FORMS ALONG THE FRONT AND TRIES TO WAVE THE FRONT BACK ONSHORE...HOWEVER FEEL MOST OF THE MOISTURE WILL STAY OFFSHORE AT THIS TIME. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD...MAINLY ALONG THE SOUTHEAST COAST OF THE CWA WITH PERIODS OF RAIN/SHOWERS AND INTERMITTENT MVFR/IFR CONDITIONS.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/... AS OF 130 PM...THE COASTAL WATERS WILL CONTINUE TO SEE WINDS INCREASE IN MAGNITUDE AND MAINTAIN A NORTHERLY COMPONENT THROUGH TUESDAY MORNING. CURRENTLY...WINDS ARE FROM THE NORTH ABOUT 10-12 KNOTS. AS HIGH PRESSURE SHIFTS ACROSS THE OHIO VALLEY THE GRADIENT WILL GRADUALLY INCREASE TO SEE A ROBUST 15 KNOTS. THE DIRECTION WILL SHIFT A BIT TO THE NORTHEAST AS WELL. SIGNIFICANT SEAS WILL SLOWLY BUILD FROM AROUND THE CURRENT 2-3 FEET TO 3-4 FEET. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...COLD FRONT STALLED JUST OFFSHORE TUESDAY MORNING WILL REMAIN NEARLY STATIONARY THROUGH MID-WEEK AS HIGH PRESSURE RIDGES DOWN THE COAST. THIS PRODUCES A PINCHED GRADIENT OVER THE WATERS...AND PERSISTENT NE WINDS OF 15-25 KTS...WITH LITTLE FLUCTUATION...BOTH TUESDAY AND WEDNESDAY. THESE GUSTY NE WINDS WILL DRIVE WAVE HEIGHTS UP TO 4-6 FT FT TUESDAY...AND REMAIN THERE ON WEDNESDAY...WITH A NE WIND WAVE THE DOMINANT GROUP. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED DURING MUCH OF THE PERIOD...BUT HOISTING THE HEADLINE WILL WAIT UNTIL MORE CERTAINTY ABOUT THE TIMING CAN BE DETERMINED. ONCE THE SCA IS ISSUED...IT WILL LIKELY REMAIN IN EFFECT FOR QUITE SOME TIME. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...THE EXTENDED WILL BE MUCH LIKE THE SHORT TERM...AS A STAGNANT PATTERN KEEPS A COASTAL TROUGH JUST OFFSHORE AND A HIGH PRESSURE WEDGE INLAND. THIS PRODUCES A PROLONGED PERIOD OF NE WINDS DUE TO A PINCHED GRADIENT...AND WINDS OF 15-25 KTS WILL BE COMMON LATE WEEK. THIS EXTENDED PERIOD OF GUSTY NE WINDS WILL KEEP WAVE HEIGHTS AT 4-6 FT PRETTY MUCH THE ENTIRE FORECAST PERIOD...AND A SMALL CRAFT ADVISORY WHICH WILL LIKELY BE HOISTED EARLIER IN THE WEEK...WILL BE NEEDED FOR MOST...IF NOT ALL...OF THE LONG TERM.
-- End Changed Discussion --
&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...SHK SHORT TERM...JDW LONG TERM...JDW AVIATION...DL

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.