Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 130306 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1106 PM EDT SAT APR 12 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTROL THE WEATHER PATTERN THROUGH EARLY NEXT WEEK...SUPPORTING DRY AND MILD CONDITIONS. A COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY...WITH INCREASING CHANCES FOR SHOWERS. HIGH PRESSURE WILL MOVE INTO THE AREA WEDNESDAY AND CONTROL AREA WEATHER INTO SATURDAY...BRINGING COOL TEMPERATURES FOR MIDWEEK FOLLOWED BY MODERATING TEMPERATURES INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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AS OF 1115 PM SATURDAY...LATEST SATELLITE IR 11-3.9 MICRON IMAGERY SHOWS A MAINLY CLEAR SKY CURRENTLY ACROSS THE FA...WITH CU OVER LAND AREAS FROM THE DAYS HEATING HAVING FOR THE MOST PART DISSIPATED. ZONAL FLOW ALOFT TO AMPLIFY SOME BY DAYBREAK SUN ALLOWING WEAK UPPER RIDGING BEGINNING TO TAKE SHAPE ACROSS THE FA. THIN CI AND POSSIBLY AC NOW LOCATED JUST UPSTREAM...WILL MAKE IT TO THE ILM CWA DURING THE PRE-DAWN SUN HRS. OVERALL...LOOKING AT A MOSTLY CLEAR SKY. LOOKING AT AREAS TO WIDESPREAD 60S FOR LOWS...WITH UPPER 50S POSSIBLE WEST OF THE I-95 CORRIDOR. SFC PG WILL RELAX SOME OVERNIGHT WHILE AT THE SAME TIME A MODEST SFC BASED INVERSION HAS DEVELOPED ACROSS THE FA. SOME LOCATIONS WILL SEE SFC WINDS TEMPORARILY DROP TO CALM CONDITIONS ALLOWING PATCHY FOG TO DEVELOP. LOOKING AT THE PRE-DAWN SUN HRS FOR THIS POSSIBLE FOG DEVELOPMENT. PREVIOUS DISCUSSION........................................... AS OF 300 PM SATURDAY...HIGH PRESSURE RIDGE EXTENDING FROM A LARGE SURFACE HIGH WELL OFF THE COAST IS SLOWLY LIFTING NORTHEAST TODAY...AND WINDS ARE RESPONDING BY BACKING SLOWLY MORE TO THE SOUTH. AT THE SAME TIME...SEA BREEZE BOUNDARY CLEARLY EVIDENT ON SATELLITE IMAGERY IS PROGRESSING WESTWARD WITHIN THE WEAK PRESSURE GRADIENT...COOLING TEMPS OFF NEAR THE COAST. THIS BOUNDARY WILL CONTINUE TO PUSH WESTWARD THROUGH THIS EVENING WHILE SLOWLY ERODING...BUT WILL CONTINUE TO ADVECT INCREASED MOISTURE INTO THE COLUMN LOCALLY. SKY CONDITIONS WILL BECOME CLEAR SHORTLY AFTER DARK THANKS TO LOSS OF HEATING...AND SOME INCREASED SUBSIDENCE BENEATH A BUILDING 5H RIDGE. THIS WILL ALLOW FOR SOME RADIATIONAL COOLING TONIGHT AS WINDS GO TO NEAR CALM WITHIN THE DRY COLUMN. HOWEVER...A LLJ IS PROGGED TO DEVELOP AND REACH TO NEARLY 20 KTS FROM THE SOUTH OVERNIGHT. THIS POSES A FORECAST CHALLENGE AS TO WHETHER FOG WILL DEVELOP TONIGHT. THE AFOREMENTIONED INCREASED MOISTURE WILL HELP DEWPOINT DEPRESSIONS FALL TO NEAR ZERO...AND NEAR-SURFACE HYDROLAPSE RATES APPEAR FAVORABLE FOR FOG. HOWEVER...THE STRENGTH OF THE LLJ MAY PRECLUDE FOG FROM DEVELOPING...AND CROSSOVER TEMPS ARE NOT EXPECTED TO BE MET (ALTHOUGH IN A SITUATION LIKE THIS WITH MOIST ADVECTION CONTINUING OVERNIGHT CROSSOVER TEMPS MAY NOT BE THE BEST PROXY FOR FOG). STILL...HAVE KEPT PATCHY FOG AREA-WIDE...WITH SOME AREAS OF FOG CLOSER TO THE COAST WHERE MOISTURE WILL BE GREATER. DO NOT EXPECT WIDESPREAD OR DENSE FOG HOWEVER. MINS TONIGHT ARE FORECAST ABOVE GUIDANCE...FALLING TO AROUND 60 AT THE COAST AND MID 50S IN THE COOLEST SPOTS INLAND.
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&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS TO 300 PM SATURDAY...HIGH PRESSURE WILL YIELD ANOTHER 24 HOURS OF FAIR WEATHER BEFORE CONDITIONS SLOWLY DETERIORATE MONDAY AND MONDAY NIGHT. MAINLY CLEAR SKIES ARE EXPECTED SUNDAY AND SUNDAY NIGHT MAXIMUMS IN THE MID 70S TO AROUND 80 WITH MINS IN THE UPPER 50S AND LOWER 60S. CLOUDS WILL INCREASE AHEAD OF AN APPROACHING COLD FRONT MONDAY AND MONDAY NIGHT SUCH THAT MAINLY CLOUDY SKIES ARE EXPECTED MONDAY EVENING INTO MONDAY NIGHT. THERE IS A SMALL CHANCE FOR A SHOWER OR THUNDERSTORM MONDAY AFTERNOON IN CONFLUENT S TO SE LOW LEVEL FLOW. MAX TEMPERATURES MONDAY WILL BE A DEGREE OR TWO COOLER THAN SUNDAY DUE TO THE INCREASE IN CLOUD COVER. AS THE FRONT GETS CLOSER MONDAY NIGHT...INCREASING MOISTURE COMBINED WITH WEAK LIFT ASSOCIATED WITH THE FRONT AND ATTENDANT UPPER SUPPORT SHOULD RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. POPS WILL MAX OUT MONDAY NIGHT IN THE HIGH CHANCE RANGE WITH MINS IN THE LOWER TO MIDDLE 60S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 PM SATURDAY...THE FIRST PART OF THE FORECAST PERIOD LOOKS STORMY AND WET AHEAD OF A STRONG COLD FRONT AND VIGOROUS UPPER LEVEL TROUGH. THE FRONT LOOKS LIKE IT WILL SLOW DOWN AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE BOUNDARY...BUT THE FRONT IS EXPECTED TO FINALLY PUSH ACROSS THE AREA AND OFFSHORE LATE DAY TUE AND TUE EVE. THIS SHOULD PROLONG THE PERIOD OF TIME THAT WE ARE IN AN ENVIRONMENT CONDUCIVE FOR CONVECTION AND HEAVY RAIN. PRECIPITABLE WATER VALUES TOP AN INCH AND A HALF. THE LIFT ASSOCIATED WITH THE FRONT AND THE WAVE OF LOW PRESSURE AT THE SURFACE AND THE UPPER LEVEL SUPPORT ALOFT COUPLED WITH DEEP MOISTURE PER MODEL SOUNDINGS SUPPORT HIGH POPS AND HAVE DECIDED TO GO WITH CATEGORICAL POPS DURING TUE/TUE NIGHT. RAINFALL AMOUNTS COULD EASILY REACH ONE-HALF TO ONE INCH WITH HIGHER AMOUNTS POSSIBLE. ALTHOUGH INSTABILITY DOES NOT LOOK ROBUST AT THIS TIME...GIVEN THE STRENGTH OF THE LOW LEVEL JET...AROUND 50 KT...IT IS POSSIBLE THAT THE STRONGEST STORMS COULD PRODUCE ISOLATED STRONG TO DAMAGING WIND GUSTS IN WET MICROBURSTS. HIGH PRESSURE SHOULD BEGIN BUILDING ACROSS THE EASTERN CAROLINAS IN THE WAKE OF THE FRONT AND WITH TIME...THE HIGH STRENGTHENS AS IT MOVES TO NEW ENGLAND WITH A WEDGE SIGNATURE DEVELOPING WED AND PERHAPS EVEN STRENGTHENING FURTHER ON THU. GIVEN FLOW ALOFT WILL REMAIN WSW TO SW ATOP A COOL AND SHALLOW NE FLOW...WILL HAVE TO WATCH FOR THE REDEVELOPMENT OF LIGHT PRECIPITATION MID-WEEK. HOWEVER...AT THIS TIME PROSPECTS LOOK SMALL FOR ADDITIONAL RAINFALL GIVEN THE MAGNITUDE OF DRY AIR ALOFT. LOWER CLOUDS MAY ALSO BE PLENTIFUL FOR MID AND LATE WEEK. THE WEDGE WILL FINALLY BEGIN TO WEAKEN WITH THE APPROACH OF THE WEEKEND AND NE WINDS WILL BEGIN TO VEER TO E AND POSSIBLY SE BY THE END OF THE PERIOD AS A COASTAL TROUGH BEGINS TO DEVELOP ALONG THE CAROLINA COAST. THE RISK FOR RAINFALL WILL BE ON THE INCREASE AS NEXT WEEKEND APPROACHES. A COOL AND RATHER CLOUDY WORK WEEK AHEAD...IN STARK CONTRAST TO THE LAST FEW DAYS. HIGHS ON WED AND THU MAY NOT GET OUT OF THE 50S WITH A STINGING NE WIND BLOWING. TEMPS WILL BE NEAR NORMAL TUE AND THEN AGAIN NEXT SAT. ALTHOUGH A FREEZE IS NOT EXPECTED NEXT WEEK...WE ARE EXPECTING WELL BELOW NORMAL MINIMUMS FOR MUCH OF THE PERIOD. LOWS WILL BE IN THE LOWER TO MID 40S WED NIGHT AND THU NIGHT WITH SOME ISOLATED UPPER 30S POSSIBLE INLAND. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... AS OF 00Z...EXPECT VFR THROUGH THE VALID PERIOD...WITH THE EXCEPTION OF POSSIBLE MVFR/IFR DUE TO PATCHY FOG/STRATUS OVERNIGHT INTO THE EARLY MORNING HOURS ON SUNDAY. VFR PREVAILS ACROSS THE AREA THIS EVENING WITH A FEW PASSING MID/HIGH LEVEL CLOUDS AND SOUTHERLY WINDS AOB 10 KTS. WINDS WILL BECOME LIGHT OVERNIGHT...AND WITH AVAILABLE LOW LEVEL MOISTURE COULD SEE PATCHY AREAS OF FOG...ESPECIALLY ALONG THE COAST. POTENTIALLY INCREASING LOW LEVEL JET COULD SPARK LOW LEVEL STRATUS DEVELOPMENT AS WELL...POSSIBLY IN PLACE OF FOG. CONFIDENCE IS LOWERED ON EXACT TIMING AND AREAS OF DEVELOPMENT...BUT OVERALL ANTICIPATE MVFR/POTENTIAL IFR DUE TO FOG AND/OR STRATUS. EXPECT VFR TO RETURN JUST AFTER DAYBREAK ON SUNDAY WITH FEW/SCT HIGH CLOUDS/AFTERNOON CU POSSIBLE...AND SOUTHWEST FLOW AOB 10 KTS...INCREASING IN THE AFTERNOON HOURS...ESPECIALLY ALONG THE COAST. EXTENDED OUTLOOK...CHANCE OF SHOWERS AND MVFR CONDITIONS LATE MONDAY THROUGH TUESDAY WITH SHOWERS AND/OR THUNDERSTORMS ALONG A PASSING COLD FRONT. OTHERWISE VFR. && .MARINE...
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NEAR TERM /THROUGH TONIGHT/... AS OF 1115 PM SATURDAY...STALLED BACK DOOR COLD FRONT JUST NORTH OF THE FA...WILL LIFT BACK TO THE NORTH FURTHER AWAY FROM THE AREA WATERS OVERNITE. SFC RIDGE AXIS EXTENDING WSW FROM THE WESTERN ATLANTIC HIGH...WILL CROSS PORTIONS OF THE AREA WATERS. AS A RESULT...LOOKING AT A SSE-S WIND DIRECTION OVERNIGHT...WITH A SOMEWHAT RELAXED SFC PG YIELDING AROUND 10 KT FOR SPEEDS. SIGNIFICANT SEAS WILL RUN 2 TO OCCASIONALLY 3 FEET...WITH A LAZY BORDERLINE SE-SSE 1 TO 2 FOOT GROUND SWELL DOMINATING THE SEAS. DOMINANT PERIODS WILL RUN 7 TO 8 SECONDS. PREVIOUS DISCUSSION................................................. AS OF 300 PM SATURDAY...HIGH PRESSURE CENTERED WELL OFF THE COAST CONTINUES TO EXTEND A SURFACE RIDGE AXIS TOWARDS THE SOUTHEAST. THIS RIDGE AXIS IS SLOWLY LIFTING NORTHEAST...AND ALTHOUGH THE PRESSURE GRADIENT REMAINS VERY WEAK...WINDS ARE SLOWLY SHIFTING MORE TO THE SOUTH AT 5-10 KTS. WINDS ON THE IMMEDIATE COAST WITHIN THE SEA BREEZE CIRCULATION HAVE GUSTED UP TO 15 KTS AT TIMES...BUT THESE WILL EASE THIS EVENING. ALTHOUGH SPEEDS WILL REMAIN ONLY AROUND 10 KTS TONIGHT...SEAS WILL BUILD SLIGHTLY FROM 1-2 FT...TO 2-3 FT THANKS TO THE LONGER FETCH. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS TO 300 PM SATURDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE COAST AS COLD FRONT NEARS THE CAROLINAS BY LATE MONDAY. THIS WILL PRODUCE AN INCREASING S TO SE RETURN FLOW THROUGH MONDAY NIGHT. SPEEDS WILL RUN 10 TO 15 KT INTO MONDAY BEFORE INCREASING TO 15 TO 20 KT MONDAY NIGHT. SEAS OF 2 TO 3 FT SUNDAY WILL GRADUALLY BUILD DUE TO PERSISTENT S TO SE FLOW THROUGH THE PERIOD...PEAKING AT 4 TO 6 FT BETWEEN 06Z AND 12Z TUESDAY. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 300 PM SATURDAY...A PROLONGED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS IS EXPECTED. GUSTS TO GALE FORCE ARE POSSIBLE LATE TUE NIGHT INTO WED. A WAVE OF LOW PRESSURE IS EXPECTED TO DEVELOP ON A STRONG COLD FRONT...SLOWING THE OFFSHORE PROGRESSION. THE FRONT IS EXPECTED TO FINALLY PUSH OFFSHORE TUE NIGHT. THE TIGHTEST PRESSURE GRADIENT IS EXPECTED TO DEVELOP IN THE WAKE OF THE FRONT AS STRONG HIGH PRESSURE NOSES INTO THE CAROLINAS LATE TUE NIGHT AND THEN EVOLVES INTO A WEDGE OF HIGH PRESSURE WED AND THU. THE STRONGEST WINDS WILL LIKELY OCCUR LATE TUE NIGHT INTO WED AND IT IS DURING THIS TIME THAT GUSTS TO GALE FORCE ARE MOST PROBABLE. SUSTAINED WIND SPEEDS MAY REACH GALE CRITERIA DURING THIS TIME. ONCE THE VERY TIGHT PRESSURE GRADIENT DEVELOPS...IT IS EXPECTED TO PERSIST. THEREFORE... WIND SPEEDS ARE EXPECTED TO REMAIN ABOVE SMALL CRAFT ADVISORY THRESHOLDS INTO THU NIGHT. THE WIND DIRECTION WILL BE S AND SW AHEAD OF THE FRONT TUE AND TUE EVE...SHIFTING TO N OVERNIGHT TUE AND THEN A LONG DURATION OF NE WINDS WED THROUGH THU NIGHT. SEAS WILL BE NEAR OR JUST ABOVE 6 FT ACROSS THE OUTER WATERS EVEN ON TUE...BUT WILL RAMP UP TUE NIGHT AND WED AS DRY AND CHILLY NE SURGE ENVELOPS THE WATERS...REACHING UP TO 6 TO 9 FT AND 10 FT NEAR FRYING PAN SHOALS BUOY. SEAS WILL LIKELY NOT FALL BELOW 6 FT ACROSS THE OUTER WATERS UNTIL THU NIGHT OR FRI.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RAN NEAR TERM...DCH/JDW SHORT TERM...RAN LONG TERM...RJD AVIATION...SGL

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