Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 150835 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 435 AM EDT MON SEP 15 2014 .SYNOPSIS... A FRONT STALLED ACROSS SOUTHERN GEORGIA WILL RETURN NORTH TODAY...ONLY TO BE PUSHED SOUTH AGAIN TUESDAY AS HIGH PRESSURE BUILDS EASTWARD ACROSS THE PLAINS STATES. THIS HIGH WILL MOVE ACROSS THE MID-ATLANTIC STATES LATE IN THE WEEK...PROVIDING FALL- LIKE WEATHER WEDNESDAY THROUGH SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM MONDAY...THE FA MAINLY UNDER A LONGWAVE LOW AMPLITUDE UPPER TROF. THIS FLATTENED UPPER TROF HAS PREVENTED THE SFC COLD FRONT FROM PROGRESSING TOO FAR SOUTH DURING THE PAST COUPLE DAYS. AS FOR PCPN THIS MORNING...WEAK ISENTROPIC LIFT NORTH OF THE MEANDERING FRONTAL BOUNDARY JUST SOUTH OF THE FA...WILL INITIALLY BE THE DRIVING FORCE FOR LIGHT RAIN SHOWERS OR DRIZZLE...ESPECIALLY ACROSS THE ILM SC COUNTIES THIS MORNING. THE FRONTAL BOUNDARY WILL REVERSE COURSE TODAY AND LIFT BACK SLOWLY TO THE NORTH...WHILE AT THE SAME TIME SLOWLY DISSIPATING. FOR THIS AFTERNOON...INSOLATION WILL HELP WITH SOME INCREASING INSTABILITY. LIFT...ALBEIT WEAK...FROM THE LIFTING FRONT...WILL AID IN THE DEVELOPMENT OF THUNDERSTORMS. LOW-MEDIUM CHANCE FOR PCPN THIS AFTN INTO THIS EVENG. FOR TONIGHT...WEAK SFC TROF/COLD FRONT TO APPROACH FROM THE WEST BY TUE DAYBREAK. MODELS SOMEWHAT NOISY WITH DYNAMICS ALOFT IE. EMBEDDED S/W TROF OR VORT...IN THAT WILL HOLD ONTO THE CHANCE FOR PCPN AND NOT GO ANY HIER AT THE MOMENT. AS FOR TEMPS...HAVE COMPROMISED BETWEEN THE NAM AND GFS MOS GUIDANCE FOR BOTH MAX/MIN FCST. WITH ANY BREAKS IN THE CLOUDINESS...THE WARMER GFS MAY BE THE WAY TO GO FOR MAXES TODAY. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...MID LEVEL RIDGING WILL SHARPEN AND MOVE ACROSS THE WEST COAST AS TROUGHING DEVELOPS ACROSS THE EASTERN THIRD OF THE U.S. THIS TROUGH WILL EVENTUALLY PUSH A COLD FRONT THROUGH THE AREA LATE TUESDAY INTO EARLY WEDNESDAY. WILL MAINTAIN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS FOR TUESDAY AS THE LINGERING MOISTURE WARRANTS AHEAD OF THE FRONT. MORE OF A SHOWERY SCENARIO FOR WEDNESDAY ESPECIALLY ACROSS NORTH CAROLINA. STILL ENOUGH INSTABILITY TO WARRANT SLIGHT CHANCE OF THUNDER NORTH WITH THUNDERSTORMS THE PRIMARY MODE FOR SOUTH CAROLINA. TEMPERATURES STILL ON THE WARM SIDE FOR TUESDAY IN THE MIDDLE 80S DROPPING A GOOD FIVE TO TEN DEGREES WEDNESDAY. OVERNIGHT LOWS WILL BE IN THE 60S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...THE EXTENDED FORECAST CONTINUES TO SHOW A MOSTLY ZONAL MID LEVEL PATTERN INITIALLY WITH MORE AMPLITUDE DEVELOPING LATE. THE WESTERLIES WILL SHOW CONFLUENCE ACROSS THE CENTRAL PLAINS/GREAT LAKES WHICH WILL ALLOW A RATHER EXPANSIVE AREA OF SURFACE HIGH PRESSURE TO BUILD DOWN THE EAST COAST. THIS WILL MAINTAIN A SOMEWHAT DRY AND COOL FLOW ACROSS OUR FORECAST AREA. THE HIGH WEAKENS AS MID LEVEL SUPPORT WANES AND HIGH PRESSURE BUILDS ACROSS THE WESTERN U.S. AT THE MID LEVELS. THIS WILL SET THE STAGE FOR ANOTHER SYSTEM TO AFFECT THE AREA LATE OR JUST BEYOND THIS FORECAST PERIOD. TEMPERATURES WILL BE JUST A LITTLE BELOW CLIMATOLOGY MODERATING EVER SO SLIGHTLY LATE IN THE PERIOD. THE ONLY POPS ARE RELEGATED TO JUST OFFSHORE WHERE JUST ENOUGH MOISTURE WARRANTS. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... AS OF 06Z...MVFR CIGS 1-2KFT WILL PREVAIL OVERNIGHT WITH THE ILM SC TERMINALS POSSIBLY OBSERVING CIGS LESS THAN 1K FT IN A 3-5 HR WINDOW SURROUNDING DAYBREAK MON DUE TO THEIR CLOSER PROXIMITY TO THE STALLED COLD FRONT SOUTH OF THE AREA. CANNOT RULE OUT TEMPO IFR CIGS AT KILM AND ESPECIALLY KLBT...AND MAY INCLUDE A SUB 2K FOOT CEILING AT LBT AT PRESS TIME. FOG DOES NOT SEEM LIKE A BIG CONCERN GIVEN THE PERSISTENT NORTHEAST FLOW AND EXTENSIVE CLOUD COVER...BUT WE COULD SEE SOME MVFR VSBYS INLAND. GUIDANCE SUGGESTS FOG MAY BECOME A PLAYER TOWARD DAYBREAK ACROSS THE INLAND TERMINALS...DROPPING VSBYS BELOW 1SM. FOR NOW WILL KEEP THE LOW STRATUS DECK AS THE MAJOR PLAYER FOR ANY IFR CONDITIONS. LIGHT NORTH TO NORTHEAST WINDS AT THE START WILL VEER TO THE EAST AND SOUTHEAST LATER IN THE DAY. HAVE ADDED VCSH FOR THE SOUTHERN TERMS AFTER 20Z AS THE WASHED OUT BOUNDARY LIFTS BACK NORTHWARD ACROSS OUR CWA. EXTENDED OUTLOOK...CHANCE OF SHOWERS/TEMPO MVFR TUE AHEAD OF A COLD FRONT. POST-FRONTAL MVFR CIGS MAY DEVELOP WED AS COOLER AIR WEDGES INTO THE REGION. OTHERWISE EXPECT VFR THROUGH FRI. && .MARINE...
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NEAR TERM /THROUGH TONIGHT/... AS OF 400 AM MONDAY...MODEL SFC PRESSURE PATTERN AND WEAK GRADIENT SUPPORT A WEAK WEDGE THIS MORNING THAT WEAKENS AND GIVES WAY TO THE APPROACHING FRONTAL BOUNDARY FROM THE SOUTH. LOOKING AT A SLOW VEERING TREND IN THE WIND FIELD...FROM NE THIS MORNING TO EAST MIDDAY...AND SOUTHEAST THIS AFTERNOON AND EARLY EVENING. FOR TONIGHT VARIABLE WINDS INITIALLY WILL BECOME WESTERLY AS A COLD FRONT APPROACHES FROM THE WEST TOWARD DAYBREAK TUE. WIND SPEEDS INITIALLY 10 TO 15 KT DUE TO THE WEDGE...WILL DROP BACK TO AROUND 10 KT AS THE SFC PG WEAKENS. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT WITH AN AVERAGE PERIOD OF 4 TO 5 SECONDS. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...LIGHT WIND FIELDS WILL PREVAIL OVER THE WATERS FOR MOST OF TUESDAY. IF ANYTHING...WINDS WILL HAVE A NORTHERLY COMPONENT OF TEN KNOTS OR LESS. THE WINDS ACQUIRE MORE DEFINITION BY WEDNESDAY MORNING AS A FRONT MOVES SLOWLY TO THE SOUTH. EXPECT AN INCREASING NORTHEASTERLY FLOW OF 10-15 KNOTS. SIGNIFICANT SEAS INCREASE FROM 2-3 FEET TO 3-5 FEET AND POSSIBLY SOME SIX FOOTERS ACROSS THE OUTER WATERS WEDNESDAY. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...ESSENTIALLY A NORTHEAST FLOW THROUGH THE PERIOD. THE STRONGEST WINDS WILL OCCUR LATE AS HIGH PRESSURE...ANCHORED ACROSS THE NORTHEAST STRENGTHENS. SPEEDS WILL BE IN A 15-20 KNOT RANGE CLOSER TO AND POSSIBLY JUST EXCEEDING THE HIGHER END BY FRIDAY MORNING. SEAS WILL HOVER AT OR JUST BELOW SMALL CRAFT CRITERIA...3-5 FEET.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...DCH SHORT TERM...SHK LONG TERM...SHK AVIATION...DCH/BJR

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