Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 220030 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 830 PM EDT MON APR 21 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY NIGHT WITH SHOWERS AND THUNDERSTORMS EXPECTED WITH ITS PASSAGE. HIGH PRESSURE WILL BUILD OVER THE REGION WEDNESDAY THEN MOVE OFFSHORE THURSDAY AND FRIDAY. HIGH PRESSURE WILL REMAIN IN PLACE THROUGH THE WEEKEND. TEMPERATURES WILL GENERALLY BE ABOVE NORMAL. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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AS OF 745 PM MONDAY...TEMPORARY SHORT WAVE UPPER RIDGE TO PROGRESS ACROSS THE FORECAST AREA OVERNIGHT...AND OFFSHORE TUE. THIS WILL PROVIDE WEAK SFC RIDGING ACROSS THE FORECAST AREA OVERNIGHT. ONLY CLOUDS TO CONTEND WITH ARE THIN CIRRUS. A WEAK SFC BASED INVERSION TO DEVELOP AFTER SUNSET AND PERSIST THRU DAYBREAK TUE. THIS WILL ALLOW WINDS TO DECOUPLE ACROSS MOST LOCATIONS. WITH A DECENT RADIATIONAL COOLING NIGHT AND RELATIVELY MOIST GROUNDS FROM THE RECENT RAINS...WILL AID IN PATCHY TO AREAS OF FOG FORMATION... MAINLY WELL EAST OF THE I-95 CORRIDOR EXTENDING TO THE COAST. HAVE ONLY TWEAKED OVERNIGHT LOWS BY A DEGREE OR 2 IN EITHER DIRECTION. HAVE BASICALLY FOLLOWED THE AVERAGE OF THE NAM AND GFS MOS GUIDANCE. PREVIOUS DISCUSSION............................................... AS OF 3 PM MONDAY...FAIR WEATHER IS EXPECTED TONIGHT AS HIGH PRESSURE BUILDS INTO THE CAROLINAS. OTHER THAN A BIT OF CIRRUS OVERNIGHT...CLEAR SKIES WILL PREVAIL AS A SURFACE RIDGE DOMINATES OUR WEATHER. WINDS WILL SUBSIDE SOON AFTER SUNSET...BECOMING LIGHT AND VARIABLE OVERNIGHT. GOOD RADIATIONAL COOLING SHOULD ALLOW TEMPERATURES TO FALL INTO THE UPPER 40S INLAND AND AROUND 50 ALONG THE COAST.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...SHORTWAVE TROUGH WILL DRIVE A COLD FRONT ASSOCIATED WITH A NORTHERN STREAM SFC LOW/5H TROUGH ACROSS THE CAROLINAS TOMORROW EVENING. AHEAD OF THE FRONT BRIEF PERIOD OF SOUTHERLY RETURN FLOW AND DEEPER SOUTHWEST FLOW ALOFT WILL ADVECT SOME MOISTURE INTO THE REGION. ALONG WITH INCREASING MOISTURE TEMPS WILL CLIMB INTO THE LOWER 80S AWAY FROM THE COAST...LEADING TO A FAIR AMOUNT OF INSTABILITY. HOWEVER THINK THE LIMITED STRENGTH AND DURATION OF THE MOISTURE ADVECTION WILL KEEP COVERAGE OF CONVECTION AHEAD OF/ALONG THE FRONT SCATTERED. THUS WILL MAINTAIN INHERITED CHC POP. ANY CONVECTION THAT DOES DEVELOP SHOULD BE USHERED OFF THE COAST BY MIDNIGHT. AT THIS POINT SEVERE WEATHER DOES NOT APPEAR TO BE A CONCERN WITH WEAK TO NON-EXISTENT JETTING AND MARGINAL LAPSE RATES. COLD ADVECTION DEVELOPS LATE TUESDAY NIGHT AND CONTINUES INTO WED. HOWEVER THE COMBINATION OF LATE APRIL SUN AND DOWNSLOPE COMPONENT TO FLOW WILL WORK TO OFFSET THE ADVECTION. DEEP NORTHWEST FLOW WED AND WED NIGHT DRIES THE MID LEVELS OUT...DROPPING PRECIPITABLE WATER VALUES TO AROUND 0.30 INCH THROUGH THE END OF THE PERIOD. EXPECT VERY LITTLE IN THE WAY OF CLOUDS AND NO PRECIP CHANCES. ELONGATED SURFACE RIDGE AXIS EXTENDS SOUTH LATE WED AS WEAK MID LEVEL RIDGE BUILDS NORTH. COMBINATION OF THESE 2 FEATURES SHOULD PRODUCE A NIGHT WITH GOOD RADIATIONAL COOLING CONDITIONS. LOWS END UP IN THE LOW TO MID 40S WITH A FEW AREAS ALONG THE COAST HANGING IN THE UPPER 40S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 330 PM MONDAY...HIGH PRESSURE SETTLES OVER THE CAROLINAS THURS WITH VERY LIGHT AND MORE VARIABLE WINDS. SHOULD SEE SEA/LAND BREEZE DOMINATE UNDER LATE APRIL SUN. THIS WILL KEEP TEMPS COOLER IN THE AFTERNOON CLOSER TO THE COAST REACHING AROUND 70 BUT INLAND SHOULD MAKE IT INTO THE MID 70S. OVERNIGHT LOWS THURS NIGHT WILL BE IN THE 50S WITH DEWPOINTS STARTING TO CREEP UP BUT DECENT RADIATIONAL COOLING IN PLACE. BY LATE THURS INTO FRI A RETURN FLOW WILL SET UP AS HIGH PRESSURE SHIFTS OFF THE SOUTHEAST COAST. THIS SOUTHERLY RETURN FLOW WILL INCREASE HEADING INTO FRI AND SATURDAY AS A LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT LAKES DRAGS A COLD FRONT SOUTHEAST TOWARD THE CAROLINAS. THE INCREASINGLY WARMER AND MORE HUMID RETURN FLOW SHOULD HELP TO PUSH TEMPS UP AND PRODUCE CU AND POSSIBLY SOME LOCALIZED SHWR ACTIVITY BY FRI AFTN AS GFS SHOWS PIEDMONT TROUGH DEVELOPING. ANY SHOWERS THAT DO DEVELOP WILL HEAD TOWARD THE COAST IN WESTERLY STEERING FLOW AS THE LOW LEVEL WIND FLOW ABOVE THE SURFACE WILL BACK AND INCREASE OUT OF THE WEST. THIS WESTERLY DOWNSLOPE FLOW WILL HELP TO HEAT THINGS UP HEADING INTO THE WEEKEND...WITH TEMPS BACK UP AROUND 80. IT MAY ALSO HELP TO KEEP SEA BREEZE PINNED CLOSER TO THE COAST AND LIMIT AMOUNT OF PCP. OVERALL LOOKS LIKE BEST CHC OF CLOUDS AND SHWRS WILL COME FRI AFTN THROUGH THE EVENING. WILL ALSO INCLUDE LOW END CHC ASSOCIATED WITH FRONT SAT NIGHT...BUT LOOKS LIKE ANY UPPER LEVEL SUPPORT WILL BE BENIGN AND FRONT SHOULD MOVE THROUGH AFTER HEATING OF THE DAY CUTS OFF. NEED TO WAIT UNTIL WE MOVE CLOSER TO SEE HOW TIMING WORKS OUT. WARMEST DAYS SHOULD BE FRI AND SAT. WITH DEWPOINT TEMPS UP AROUND 60 FRI NIGHT...EXPECT WARMER OVERNIGHT TEMPS STAYING INT THE 60S MOST PLACES. CLOUDS AND WARM AIR AHEAD OF COLD FRONT SHOULD KEEP TEMPS WARMER MOST OF SAT NIGHT ALSO. HIGH PRESSURE WILL BUILD IN ON SUNDAY BUT MODELS ARE IN DISAGREEMENT AS TO HOW FAR SOUTH THIS COLD FRONT WILL GET BEFORE MOVING NORTH AS A WARM FRONT. FOR NOW WILL KEEP WITH PREVIOUS FORECAST FOR SLIGHTLY COOLER AND DRIER AIR BEHIND COLD FRONT FOR SUN INTO MONDAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 00Z...POTENTIAL FOR MVFR LATE OVERNIGHT INTO THE EARLY MORNING HOURS DUE TO AREAS OF FOG. OTHERWISE EXPECT VFR AHEAD OF AN APPROACHING COLD FRONT. LATEST SATELLITE IMAGERY DEPICTS SOME LOW CLOUDS ALONG THE COAST ALONG WITH FEW/SCT HIGH CLOUDS MOVING IN ACROSS THE AREA FROM THE WEST. EXPECT LIGHT AND VARIABLE WINDS THROUGH THE OVERNIGHT HOURS WITH LINGERING FEW HIGH CLOUDS. LATEST TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS SEEM TO BE IN A BIT OF A DISAGREEMENT REGARDING FOG DEVELOPMENT OVERNIGHT. BUT GIVEN SOMEWHAT FAVORABLE ENVIRONMENT...HAVE KEPT TEMPO GROUPS IN AT ALL SITES FOR POSSIBLE MVFR FOG. AFTER DAYBREAK...ANY FOG WILL QUICKLY DISSIPATE GIVING WAY TO HIGH CONFIDENCE FOR VFR TO PREVAIL ACROSS THE AREA. SOUTHWEST WINDS WILL INCREASE INTO THE AFTERNOON HOURS AHEAD OF AN APPROACHING COLD FRONT...WITH VCSH POSSIBLE FOR THE INLAND SITES TOWARDS THE END OF THE VALID TAF PERIOD. EXTENDED OUTLOOK...CHANCE OF SHOWERS/TEMPO MVFR TUESDAY NIGHT WITH A COLD FRONT. VFR WEDNESDAY AND THURSDAY. LOW CONFIDENCE FOR SCATTERED SHOWERS WITH TEMPO MVFR ON FRIDAY AND SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM MONDAY...SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR AMZ250/252 THROUGH 01Z TUESDAY. WINDS AND SEAS WILL DIMINISH TONIGHT AS LOW PRESSURE PULLS AWAY FROM THE CAROLINAS AND THE GRADIENT WEAKENS. OVERNIGHT...SEAS WILL FALL TO AROUND 3-4 FT NORTHERN WATERS AND 2-3 FT SOUTHERN WATERS WITH NORTH WINDS AROUND 10 KTS. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...SOUTHWEST FLOW AHEAD OF AN ADVANCING COLD FRONT WILL APPROACH 20 KT LATE TUE JUST BEFORE THE FRONT PASSES. BRIEF PERIOD OF INCREASED SOUTHWEST FLOW WILL NOT BE ABLE TO BUILD SEAS TO HEADLINE CRITERIA BUT 3 TO 5 FT IS POSSIBLE. COMBINATION OF TIGHT GRADIENT AND COLD ADVECTION BEHIND THE FRONT WILL KEEP WEST TO NORTHWEST FLOW IN THE 15 TO 20 KT RANGE TUE NIGHT. OFFSHORE WIND COMPONENT WILL QUICKLY DROP SEAS TO 2 TO 4 FT TUE NIGHT. GRADIENT WEAKENS DURING THE DAY WITH SPEEDS DROPPING FROM 15 TO 20 KT IN THE MORNING TO 10 TO 15 KT BY AFTERNOON. WINDS BECOME LIGHT AND VARIABLE WEDNESDAY NIGHT AS ELONGATED SURFACE RIDGE AXIS MOVES OVER THE AREA. SEAS 2 TO 3 FT WED MORNING DROP TO 2 FT OR LESS LATER WED AND WED NIGHT. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 330 PM MONDAY...HIGH PRESSURE WILL SHIFT OVERHEAD ON THURS WITH LIGHT AND VARIABLE WINDS OVER THE WATERS. AS THE HIGH SHIFTS FURTHER OFF SHORE THURS NIGHT INTO FRI A LIGHT RETURN FLOW WILL SET UP BUT IT WILL START INCREASING OUT OF THE S TO SW FRI AFTN AS PIEDMONT TROUGH SETS UP. THE WINDS WILL VEER A LITTLE MORE THROUGH SATURDAY AS A COLD FRONT APPROACHES THE WATERS BECOMING SW-W UP TO 15 KTS. A COLD FRONT SHOULD MOVE THROUGH THE WATERS SAT NIGHT PRODUCING AN ABRUPT SHIFT TO THE NORTH BY SUNDAY MORNING. SEAS AROUND 2 FT TO START WILL INCREASE TO 2 TO 4 FT IN INCREASING RETURNING FLOW UP TO 15 KTS OUT OF THE SW. BY SATURDAY THE SEAS WILL INCREASE FURTHER MAINLY IN THE OFF SHORE WATER WITH A MORE WESTERLY FLOW UP TO 15 KTS KEEPING GREATER SEAS IN THE OUTER WATERS UP TO 4 TO 5 FT AS FRONT APPROACHES AND MOVES THROUGH SAT NIGHT. && .ILM WATCHES/WARNINGS/ADVISORIES...
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SC...NONE. NC...NONE. MARINE...NONE.
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&& $$ SYNOPSIS...III NEAR TERM...DCH/TRA/BJR SHORT TERM...III LONG TERM...RGZ AVIATION...SGL MARINE...

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