Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
511 FXUS62 KILM 111113 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 613 AM EST THU FEB 11 2016 .SYNOPSIS... DRY AND COLD WEATHER WILL CONTINUE TODAY. A WEAK LOW PRESSURE OFFSHORE WILL SPREAD SOME PRECIPITATION ACROSS THE AREA FRIDAY...WITH A WINTRY MIX LIKELY FRIDAY MORNING INTO EARLY AFTERNOON. THE COLDEST AIR OF THE SEASON WILL FOLLOW FOR THE WEEKEND WITH RECORD LOWS POSSIBLE SUNDAY MORNING. A WARMUP WILL BEGIN EARLY NEXT WEEK WITH TEMPERATURES REBOUNDING TO NORMAL VALUES BEFORE A LOW PRESSURE SYSTEM BRINGS A GOOD CHANCE FOR RAINFALL ON TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 610 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: LATEST IN A SERIES OF DRY COLD FRONTS COUPLED WITH AN UPPER SHORT WAVE IN PROCESS OF MOVING OFFSHORE. SYSTEM WAS ACCOMPANIED BY SOME ADDITIONAL COLD ADVECTION AND SOME CIRRUS...BUT LITTLE ELSE. AS PREVIOUSLY ADVERTISED...SLOW TEMPERATURE FALLS EARLY THIS MORNING WILL ACCELERATE TOWARDS DAYBREAK AS WINDS DROP OFF WITH A SURFACE HIGH RAPIDLY BUILDING IN FROM THE SW. STILL EXPECTING LOWS IN THE LOWER TO MID 20S BY DAYBREAK. FOR TODAY...THE AFOREMENTIONED SURFACE HIGH WILL BE OVERHEAD. HIGH IS DRY AND COLD...SO EXPECT MAINLY SUNNY SKIES WITH CONTINUED BELOW- NORMAL TEMPERATURES. A CONSENSUS OF GUIDANCE GIVES US HIGHS IN THE LOWER 40S FOR OUR NORTHERN TIER OF COUNTIES WITH MID 40S MOST EVERYWHERE ELSE. THIS IS MORE THAN 15 DEGREES BELOW NORMAL. FOR TONIGHT...A WEAK LOW PRESSURE SYSTEM WILL PASS OFFSHORE JUST SOUTH AND EAST OF THE FORECAST AREA WELL AFTER MIDNIGHT. LACK OF MOISTURE AND DYNAMICS...AT LEAST DURING THIS PERIOD...WILL KEEP PRECIP LIMITED TO THE SLIGHT CHANCE CATEGORY TOWARDS DAYBREAK ON FRIDAY...AND ONLY FOR THE SOUTHERNMOST COASTAL COUNTIES OF GEORGETOWN AND HORRY. NO ACCUMULATION IS EXPECTED...AND TEMPERATURES THIS FAR SOUTH WILL BE TOO HIGH FOR ANY P-TYPE ISSUES TO ARISE. MOST OTHER PLACES WILL SEE BELOW-FREEZING TEMPERATURES THOUGH...WITH LOWS RANGING FROM THE MID 20S TO LOWER 30S IN A NORTH TO SOUTH GRADIENT. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM THURSDAY...CHALLENGING FORECAST FOR FRIDAY BEFORE EXTREMELY COLD AIR BUILDS ACROSS THE CAROLINAS ON SATURDAY. COLD FRONT OFFSHORE WILL SERVE AS A BAROCLINIC GRADIENT FOR A WEAK WAVE OF LOW PRESSURE TO DEVELOP EARLY FRIDAY...WHILE A WEDGE OF HIGH PRESSURE PERSISTS ALONG COAST. THIS WILL SET THE STAGE FOR A VERY DIFFICULT FORECAST THE FIRST HALF OF FRIDAY AS BOTH QPF AND PTYPE ARE LESS THAN CONCRETE. STRONG PIECE OF VORT ENERGY (25 S-1) WILL ROTATE THROUGH THE LONGWAVE TROUGH ACROSS THE EAST...AND ASSIST IN STRENGTHENING LOW PRESSURE ALONG THE BOUNDARY OFFSHORE. THE BEST PVA OCCURS FRIDAY AFTN...CAUSING THE LOW TO STRENGTHEN PRETTY FAR NORTHEAST OF OUR AREA AND THUS ABUNDANT MOISTURE/QPF IS NOT FORECAST FOR THE ILM CWA. HOWEVER...BROAD SW FLOW ATOP THE WEDGE AHEAD OF THIS FEATURE WILL DRIVE ISENTROPIC LIFT ON THE 285K AND 290K SURFACES...CAUSING LOW-LEVEL COLUMN SATURATION AND PRECIP ONSET. IT IS POSSIBLE SOME LIGHT PRECIP WILL BE ONGOING AT 7AM FRIDAY...BUT MOST OF THE PRECIP WILL OCCUR THIS PERIOD. THIS LEADS TO A VERY INTERESTING FORECAST AS SURFACE TEMPS AND WET- BULBS WILL BE BELOW FREEZING FRIDAY MORNING. INITIALLY...WARM NOSE TEMPERATURES WILL BE AOB 0C...BUT WITH THE INCREASING SW FLOW ATOP THE WEDGE...900-800MB TEMPS WILL CLIMB QUICKLY THROUGH THE MORNING SO THAT BY LATE MORNING THE WARM NOSE IN EVEN THE COLDEST SPOTS (NEAR LUMBERTON) WILL BE +2C...AND RISE THROUGH THE REST OF THE AFTN. SURFACE TEMPS WILL BE SLOWER TO RESPOND OF COURSE...AND WITHIN THE WEDGE EVEN THE GUIDANCE MAY BE TOO FAST IN BRINGING ABOVE FREEZING TEMPERATURES...ESPECIALLY NEAR I-95. BEFORE THE WARM NOSE DEVELOPS...THERE REMAINS A STUBBORN DRY LAYER WITHIN THE DGZ...MAKING IT UNLIKELY THAT ANY SNOW WOULD BE POSSIBLE. HOWEVER...THE AFOREMENTIONED STRONG PVA SATURATES THE COLUMN ABOVE 600MB...AND MAY PROVIDE ENOUGH VIRGA TO MOISTEN THE DGZ WHICH COULD PRODUCE SNOW SHOWERS IN A `SEEDER-FEEDER` TYPE SETUP (THANKS TO WFO RAH FOR THE TERM, THIS FORECASTER HAD A CASE OF LETHOLOGICA THIS MORNING). TOPDOWN METHODOLOGY PRODUCES A MESS OF ALL PTYPES FOR SEVERAL HOURS FRIDAY MORNING...WITH THE LONGEST DURATION OF FROZEN PRECIP OUT TOWARDS MARLBORO/ROBESON/BLADEN COUNTIES. COULD NOT GET ZR AS PREDOMINANT WXTYPE...AND MANIPULATED TO GET A R/S/IP MIX AFTER A PERIOD OF SNOW...BUT IF THE NAM (COLDEST SOLUTION) TURNS OUT TO BE CORRECT THERE COULD BE SOME ZR ACCRETION AND THIS WOULD MATCH UP PRETTY WELL WITH WPC 0.01 ACCRETION LINE JUST NORTH OF ROBESON AND BLADEN COUNTIES. FOR NOW WILL CARRY THIS MIXED PTYPE WITHOUT SHOWING ANY SNOW OR ICE ACCUMULATION. BY AFTN ALL PRECIP WILL HAVE TURNED TO RAIN AS SURFACE TEMPS CLIMB ABOVE FREEZING...BUT AS MENTIONED ABOVE CANNOT RULE OUT SOME MINOR IMPACTS DUE TO FREEZING RAIN WELL INLAND. FRIDAY NIGHT THE LOW PRESSURE WILL PULL AWAY WITH RAPID DRYING OCCURRING IN ITS WAKE. STRONG COLD ADVECTION WILL ALSO BEGIN AS THE STRONG VORT PUSHES A COLD FRONT THROUGH THE CWA...AND 850MB TEMPS CRASH BEGINNING FRIDAY NIGHT...FALLING FROM ABOUT 0C FRIDAY EVENING TO AS LOW AS -15C SATURDAY NIGHT. THIS COLD ADVECTION WILL KEEP HIGHS SATURDAY BELOW GUIDANCE WITH MANY PLACES STRUGGLING ONLY INTO THE LOW 40S...AFTER FRIDAY NIGHT LOWS DROP INTO THE UPPER 20S. THERE SHOULD BE ENOUGH WIND AND DRYING TO PREVENT RE-FREEZE ON THE ROADWAYS FRIDAY NIGHT BUT IT IS POSSIBLE SOME ICY SPOTS MAY EXIST AND THIS WILL NEED TO BE MONITORED CLOSELY ON FRIDAY. THE MINS FRIDAY NIGHT WILL FEEL DOWNRIGHT...WARM...COMPARED TO WHAT IS EXPECTED SATURDAY NIGHT AS LOWS WILL DROP TO NEAR RECORD VALUES IN THE MID TO UPPER TEENS. RECORD LOWS FOR 2/14: WILMINGTON: 18 (1968) FORECAST: 19 FLORENCE: 15 (1968) FORECAST 18 NORTH MYRTLE BEACH: 17 (1955) FORECAST: 20 IF THOSE NEAR RECORD VALUES ARE NOT ENOUGH...WINDS WILL REMAIN GUSTY ALL SATURDAY NIGHT AS COLD ADVECTION KEEPS THE BOUNDARY LAYER MIXED WITH NORTH WINDS OF 10-15 MPH FORECAST THROUGH THE OVERNIGHT. THESE WINDS COMBINED WITH THE LOW TEMPS WILL CREATE WIND CHILLS OF 5-10 DEGREES ABOVE ZERO...AND A WIND CHILL ADVISORY MAY BE NEEDED FOR PORTIONS OF THE AREA (CRITERIA +5). && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...EXTREMELY COLD TO START THE PERIOD WILL SLOWLY MODIFY THROUGH EARLY NEXT WEEK BEFORE A STRONG LOW PRESSURE SYSTEM IMPACTS THE REGION. THE CWA MAY BE RECOVERING FROM RECORD MINS SUNDAY MORNING...AND ALTHOUGH NEUTRAL TO WARM ADVECTION WILL BEGIN...SHALLOW MIXING FORECAST FOR SUNDAY WILL NEGATE FULL SUNSHINE WITHIN THE INCREASING SUN ANGLE...AND SO VALENTINE`S DAY HIGHS WILL STRUGGLE TO JUST ABOUT FREEZING IN THE NORTHERN ZONES AND MID 30S IN THE FAR SOUTH. THIS IS ABOUT 20-25 DEGREES BELOW NORMAL FOR THE DATE...AND WILL BE FOLLOWED BY ANOTHER COLD NIGHT SUNDAY NIGHT WITH LOWS FALLING INTO THE LOW AND MID 20S. THEREAFTER...SHORTWAVE RIDGING DEVELOPS BETWEEN THE DEPARTING TROUGH AND ANOTHER DEVELOPING IN THE MS VLY. THIS WILL ALLOW HIGH PRESSURE TO SKIRT OFF THE MID-ATLANTIC COAST PROMOTING WARM RETURN FLOW AT THE SURFACE...COMBINED WITH INCREASING THICKNESSES ON STRENGTHENING SW WINDS ALOFT AHEAD OF THE MS VLY TROUGH. TEMPS WILL CLIMB TO SEASONABLE VALUES BY TUESDAY...MOSTLY NEGATING ANY PTYPE ISSUES FOR THE UPCOMING LOW PRESSURE SYSTEM. HOWEVER...SOUNDINGS SUGGEST AT LEAST A CHANCE FOR SOME FROZEN PRECIP AT ONSET...WELL INLAND...AS WELL AS ON THE BACKSIDE AS A QUICK SHOT OF COLD THIS LOW COULD AIR FOLLOWS THE SYSTEM. THESE ARE BOTH VERY LOW CONFIDENCE FORECAST PARAMETERS AT THIS TIME RANGE THOUGH...AND THE MORE LIKELY SCENARIO IS A GOOD QPF RAIN EVENT WHICH COULD EXACERBATE THE ONGOING RIVER FLOODING. A QUICK WARMUP WILL RETURN ON WEDNESDAY AS MID-LEVEL THICKNESSES REBOUND. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... AS OF 06Z...CONTINUED COLD WEATHER PATTERN WITH A LONGWAVE TROUGH OVER THE EASTERN SEABOARD. WINDS OVERNIGHT SHOULD STAY ABOVE 6 KTS. SOME CIRRUS IS POSSIBLE OVER FLO OTHERWISE SKIES SHOULD REMAIN CLEAR. THURSDAY...CONTINUED WESTERLY FLOW...NOT AS STRONG AS TODAY AND DIMINISHING TOWARD SUNSET. INCREASING CLOUDS AHEAD OF THE NEXT WEAK SYSTEM...PROBABLY AFTER THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...PREDOMINATELY VFR. CHANCE OF SHOWERS ON FRIDAY AND PERHAPS MVFR AT TIMES. UNSETTLED WEATHER ON MONDAY AND TUESDAY WITH PRECIPITATION. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 610 AM THURSDAY...HAVE CANCELLED THE SMALL CRAFT ADVISORY AS CONDITIONS ARE RAPIDLY IMPROVING. LATEST OBS SHOW NW WINDS AT 15 TO 20 KTS WITH SEAS OF 2 TO 4 FT. CONDITIONS SHOULD CONTINUE TO IMPROVE THIS MORNING AS COOL AND DRY HIGH PRESSURE BUILDS IN FROM THE SW. FOR TONIGHT...NW WINDS OF AROUND 10 KTS WILL VEER TO THE NE AFTER MIDNIGHT AS A WEAK LOW PRESSURE SYSTEM PASSES SE OF THE WATERS. AS THIS IS NOT A STRONG SYSTEM...WINDS AND SEAS WILL STAY ON THE MODEST SIDE THROUGH THE OVERNIGHT HOURS. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM THURSDAY...LOW PRESSURE WILL DEVELOP WELL EAST OF THE WATERS FRIDAY AND LIFT NE QUICKLY THROUGH THE DAY. NORTHEAST WINDS OF 5-10 KTS EARLY FRIDAY WILL SHIFT TO THE NW FRIDAY NIGHT AS THE LOW DEPARTS...AND THEN INCREASE STEADILY TO 15-20 KTS BY SATURDAY MORNING. WINDS INCREASE EVEN FURTHER ON SATURDAY TO 20-25 KTS FROM THE NW BEFORE EASING SLIGHTLY AND VEERING TO THE NORTH LATE. ALTHOUGH THE WIND DIRECTION WILL BE OFFSHORE DURING THE PERIOD OF HIGHEST SPEEDS...WAVE HEIGHTS WILL INCREASE QUICKLY ONCE WINDS TURN TO THE NW...FROM 1-2 FT TO 3-5 FT...AND THEN REMAIN AT THESE AMPLITUDES THROUGH SATURDAY NIGHT. ANY 6 FT SEAS ARE EXPECTED TO BE JUST OUTSIDE OF THE COASTAL WATERS...BUT WIND SPEEDS APPROACHING 25 KTS MAY STILL NECESSITATE AN SCA FOR SATURDAY. LONG TERM /SUNDAY THROUGH MONDAY/... AS OF 300 AM THURSDAY...HIGHLY VARIABLE WINDS AND SEAS WILL PLAGUE THE EXTENDED...AND A VARIETY OF MARINE CONDITIONS ARE FORECAST. FOR SUNDAY...NORTH WINDS OF 15-20 KTS WILL GREET THE MORNING BEFORE VEERING AND SLOWLY EASING AS HIGH PRESSURE BUILDS EAST TOWARDS THE WATERS. BY MONDAY MORNING...WINDS WILL BE EASTERLY AROUND 10 KTS...BUT THEN STEADILY INCREASE THROUGH THE REMAINDER OF THE EXTENDED AHEAD OF AN APPROACHING STRONG STORM SYSTEM. WINDS WILL VEER TO THE SE THROUGH THE DAY...AND RISE TO 15-25 KTS LATE. SHORT PERIOD 3-5 FT SEAS SUNDAY WILL DEAMPLIFY TO 1-2 FT DURING THE TRANSITION IN WIND REGIMES SUNDAY NIGHT INTO MONDAY...BUT WILL INCREASE QUICKLY AGAIN THROUGH MONDAY. WAVE HEIGHTS BECOME 4-7 FT WITH A LONGER PERIOD SE WAVE DEVELOPING LATE...AND RENEWED HEADLINES WILL LIKELY BE NEEDED. && .TIDES/COASTAL FLOODING... AS OF 610 AM THURSDAY...HAVE ISSUED YET ANOTHER COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR THE LOWER CAPE FEAR RIVER. GUIDANCE INDICATES THAT WE WILL SEE THIS MINOR COASTAL FLOODING THROUGH AT LEAST THE NEXT SEVERAL TIDE CYCLES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR NCZ107. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...REK SHORT TERM...JDW LONG TERM...JDW AVIATION...REK/DL MARINE...REK/JDW TIDES/COASTAL FLOODING...REK

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