Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 181414 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1014 AM EDT SAT APR 18 2015 .SYNOPSIS... UNSETTLED CONDITIONS WILL CONTINUE THROUGH MONDAY AS A SERIES OF WEATHER SYSTEMS MOVE ACROSS THE AREA. QUIETER CONDITIONS ARE EXPECTED BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM SATURDAY...LIGHT TO MODERATE RAIN STILL FALLING ACROSS THE EASTERN THIRD OF THE CWA. LATEST HIGH RESOLUTION GUIDANCE SHOWS THE FORECAST TREND IN GOOD SHAPE WITH A CONTINUATION OF THIS ACTIVITY FOR A FEW MORE HOURS. THIS WILL BE FOLLOWED BY A LULL THEN SOME MORE CONVECTIVE DEVELOPMENT. I DID ADJUST POPS SLIGHTLY TO INCREASE THE NEXT COUPLE OF HOURS THEN FOR BEYOND 1800 UTC AS CONVECTIVE TEMPERATURES ARE RATHER LOW AND WITH ONLY A FEW BREAKS IN THE CLOUD COVER NUMEROUS SHOWERS SHOULD POP UP. TRIMMED BACK HIGHS SLIGHTLY BASED ON CURRENT OBSERVATIONS. NO OTHER CHANGES. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...STILL SHAPING UP TO BE A VERY WET PERIOD FOR THE SHORT TERM AHEAD OF A COLD FRONT WHICH WILL CROSS THE AREA MONDAY NIGHT. SUNDAY WILL BEGIN DRY ACROSS MOST OF THE AREA...BUT THIS WILL QUICKLY CHANGE AS A LOW PRESSURE SYSTEM BENEATH A POTENT SHORTWAVE DEVELOPS AND MOVES OUT OF THE GULF STATES AND INTO THE OHIO VLY. A WARM FRONT AHEAD OF THIS FEATURE WILL MOVE OVERHEAD THE CAROLINAS...WITH A SECONDARY AREA OF LOW PRESSURE POSSIBLY DEVELOPING OVERHEAD LATE SUNDAY NIGHT. DEEP SW FLOW WILL INTENSIFY LATE SUNDAY...WITH 850MB V-WIND COMPONENT REACHING +3 SD`S LATE SUNDAY NIGHT...SUPPORTING AN ENVIRONMENT OF POTENTIALLY RECORD-FOR- THE-DAY PRECIPITABLE WATER AS COMPARED AGAINST THE SPC SOUNDING CLIMATOLOGY. ALTHOUGH A NICE SUBTROPICAL JET WILL ARC ACROSS THE MEXICO/US BORDER SUNDAY NIGHT...THIS WILL NOT AID IN ANY LIFT SO UPPER SUPPORT LOOKS TO BE PRETTY WEAK INVOF THIS SYSTEM. HOWEVER...SURFACE CONVERGENCE NEAR THE LOW PRESSURE COMBINED WITH STRONG LOW-LEVEL MOISTURE TRANSPORT...WARM CLOUD DEPTH OF 11-12 KFT...AND ONLY WEAK INSTABILITY WHICH PROVIDES LONG PARCEL RESIDENCE TIMES WITHIN THE SATURATED COLUMN...SUGGEST PERIODS OF HEAVY RAINFALL WILL OCCUR...ESPECIALLY SUNDAY NIGHT. INSTABILITY LOOKS PRETTY LIMITED SO THUNDER WILL BE ONLY ISOLATED...BUT HEAVY SHOWERS PRODUCING WIDESPREAD 1" OF QPF OR MORE LOOKS VERY LIKELY INTO MONDAY MORNING. MUCH DRIER AIR WILL FILTER INTO THE REGION MONDAY...BUT CONTINUED DEEP SW FLOW AND THE APPROACH OF A COLD FRONT WILL STILL CREATE THE POTENTIAL FOR SCATTERED SHOWERS. BEST CHANCE WILL BE LATE MONDAY INTO MONDAY NIGHT IMMEDIATELY AHEAD OF AND ALONG THE BOUNDARY...WHICH IS PROGGED TO MOVE OFFSHORE BY THE END OF THE PERIOD. TEMPS THROUGH THE PERIOD WILL BE NORMAL-TO-ABOVE FOR MID-APRIL. MONDAY WILL BE THE WARMER DAY WITH FEWER CLOUDS ALLOWING FOR MORE INSOLATION TO WARM THE SURFACE. 850MB TEMPS BOTH DAYS WILL BE 12- 14C...BUT CLOUDS AND RAIN WILL KEEP HIGHS IN THE MID 70S SUNDAY...WARMING INTO THE LOW 80S AWAY FROM THE COAST MONDAY. LOWS SUNDAY NIGHT WILL STRUGGLE TO DROP ONLY INTO THE UPR 60S...LOW 60S BEHIND THE FRONT MONDAY NIGHT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY...COLD FRONT WILL BE OFFSHORE TUESDAY MORNING...AND A PRIMARILY QUIET WEEK LOOKS TO BE ON TAP FOR THE EXTENDED. HIGH PRESSURE WILL MOVE ACROSS THE SOUTHERN TIER OF STATES TUE-THU BEFORE PUSHING OFFSHORE LATE IN THE WEEK. THIS OCCURS IN RESPONSE TO FORCED-ZONAL FLOW SOUTH OF A LARGE CLOSED LOW WHICH WILL SIT AND SPIN ACROSS SE CANADA THROUGH MUCH OF THE WEEK. THE CAROLINAS WILL BE ON THE PERIPHERY OF THIS FEATURE...SO WHILE COOLER TEMPS WILL OCCUR TUE/WED...SEASONABLE VALUES ARE ANTICIPATED. LATE IN THE PERIOD AS THE HIGH PUSHES OFFSHORE...MOIST RETURN FLOW WILL DEVELOP AND SHOWER ACTIVITY WILL BECOME POSSIBLE ONCE AGAIN THURSDAY...AND ESPECIALLY FRIDAY. FRIDAY WILL FEATURE THE BEST CHANCES FOR PRECIP BOTH DUE TO INCREASED COLUMN MOISTURE...BUT ALSO THANKS TO A COLD FRONT WHICH WILL APPROACH FROM THE NW...DRIVEN BY A PIECE OF VORT ENERGY ROTATING AROUND THE AFOREMENTIONED LARGE UPPER LOW. TEMPS THU/FRI WILL RETURN TO ABOVE NORMAL HOWEVER. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 12Z...A RATHER LARGE BATCH OF PRECIP IS CURRENTLY PASSING THROUGH THE CWA FROM WEST TO EAST...ASSOCIATED WITH A SHORT WAVE. LOOK FOR INTERMITTENT MVFR WITH POSSIBLE BRIEF IFR PERIODS IN THE HEAVIER PRECIP. THE SHORTWAVE AND ASSOCIATED PRECIP WILL EXIT THE REGION BY LATE MORNING...HOWEVER IT IS LIKELY THAT MVFR CEILINGS WILL REMAIN FOR SOME TIME AFTER THAT. HIGH PRESSURE CENTERED TO OUR NORTH WILL GIVE US LIGHT NORTHEAST FLOW TODAY. THROUGH THE EVENING HOURS MAINLY A MID CLOUD CEILING WILL PREVAIL. EXTENDED OUTLOOK...SHOWERS ACCOMPANIED WITH ISOLATED THUNDER TO AFFECT THE FORECAST AREA LATE SUNDAY THROUGH MONDAY MORNING...RESULTING IN OCCASIONAL MVFR AND IFR CONDITIONS. SCATTERED PCPN ASSOCIATED WITH A CFP MONDAY NIGHT FOLLOWED BY MAINLY VFR CONDITIONS TUE THROUGH WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM SATURDAY...RATHER QUIET ON THE COASTAL WATERS FROM A WIND AND WAVE STANDPOINT WITH A LIGHT NORTH TO NORTHEAST FLOW AND SEAS OF 2-4 FEET. NO CHANGES NEEDED TO THE CURRENT FORECAST. PREVIOUS DISCUSSION FOLLOWS: A VERY DISORGANIZED SURFACE WEATHER PATTERN EXISTS ACROSS THE AREA. WEAK LOW PRESSURE THAT DEVELOPED A COUPLE DAYS AGO ALONG AN OLD STATIONARY FRONT IS DISSIPATING OFF THE SOUTH CAROLINA COAST. MORE IMPORTANT TO OUR WEATHER WILL BE THE PASSAGE OF AN UPPER LEVEL DISTURBANCE THIS MORNING WHICH PROMISES TO BRING GOOD CHANCES FOR SHOWERS. BEHIND THIS DISTURBANCE LOOK FOR PARTIAL CLEARING AND A REDUCTION IN RAIN COVERAGE FOR THE AFTERNOON. BY LATE TONIGHT THE APPROACH OF ANOTHER DISTURBANCE FROM THE SOUTHWEST COULD BRING INCREASING SHOWER CHANCES IN AROUND DAYBREAK. VARIABLE WINDS TODAY SHOULD REMAIN 10 KNOTS OR LESS. SEAS AS HIGH AS 4 FEET IN THE 10-20 MILE OFFSHORE WATERS NEAR CAPE FEAR WILL SUBSIDE THIS AFTERNOON...WITH 2-3 FEET SEAS EXPECTED FOR ALL AREAS. VERY LATE TONIGHT HIGH PRESSURE OVER SE CANADA WILL PUSH A BACKDOOR FRONT TOWARD THE AREA...WITH INCREASING NE WINDS EXPECTED AROUND DAYBREAK SUNDAY. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...STRENGTHENING SOUTHERLY FLOW AHEAD OF A COLD FRONT WILL PRODUCE GUSTY WINDS AND A POSSIBLE SHORT SCA SUNDAY NIGHT INTO MONDAY. BEFORE THIS TIME...WINDS WILL VEER FROM E TO S THROUGH SUNDAY AS HIGH PRESSURE MOVES OFF TO THE NE AND A WARM FRONT LIFTS ACROSS THE WATERS. AS THE WINDS VEER THEY WILL INCREASE AS WELL...BECOMING 15-20 KTS SUNDAY NIGHT INTO MONDAY...AND THESE WINDS WILL PUSH SEAS UP TO 3-6 FT...HIGHEST ACROSS THE NC WATERS. A SHORT DURATION SCA STILL LOOKS LIKELY AND IS HIGHLIGHTED IN THE HWO. WINDS WILL SLOWLY VEER THROUGH MONDAY TO THE SW AT SIMILAR SPEEDS...BEFORE THE COLD FRONT CROSSES THE WATERS AT THE END OF THE PERIOD WITH A WIND SHIFT TO THE NW. SEAS MONDAY WILL BE 3-5 FT AHEAD OF THE COLD FRONT...BEFORE FALLING AS THE WINDS TURN OFFSHORE LATE. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY...HIGH PRESSURE MOVING ACROSS THE SOUTHERN TIER OF THE NATION WILL DRIFT ACROSS THE WATERS DURING WEDNESDAY. AHEAD OF THIS...LIGHT NW WINDS WILL OCCUR OVER THE WATERS...BECOMING VARIABLE WEDNESDAY AS THE GRADIENT WEAKENS...AND EVENTUALLY TURNING TO THE SW LATE...BUT STILL AT SPEEDS GENERALLY 10 KTS OR LESS. A VERY BRIEF PERIOD OF 3-5 FT SEAS ARE POSSIBLE EARLY TUESDAY...LEFTOVERS FROM THE MORE STRONGLY FORCED SEAS ON MONDAY...BEFORE FALLING TO 2-3 FT AND PERSISTING THROUGH MID-WEEK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...SHK SHORT TERM...JDW LONG TERM...JDW AVIATION...DL

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