Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 280223 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 923 PM EST THU NOV 27 2014 .SYNOPSIS... COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH FRIDAY... MOVING OVERHEAD BY SATURDAY...AND THEN OFFSHORE. THIS WILL BRING A SIGNIFICANT WARMING TREND DURING THE WEEKEND AND ON MONDAY. A BACKDOOR COLD FRONT WILL SHIFT WINDS BACK TO THE NORTH TUESDAY AND WEDNESDAY WITH MUCH COOLER TEMPERATURES. LITTLE TO NO PRECIPITATION IS EXPECTED THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... AS OF 9 PM THURSDAY...HIGH PRESSURE BUILDING IN FROM THE WEST HAS STARTED TO USHER IN A COOLER AND DRIER AIR MASS. A FEW COLD AIR INSTABILITY CLOUDS CONTINUE TO LINGER OVER THE AREA...BUT THESE SHOULD DISSIPATE WITHIN THE NEXT FEW HOURS AS SIGNIFICANT DRY AIR STARTS TO BUILD IN. EVIDENCE OF THIS DRY AIR CAN BEE SEEN IN DEWPOINTS UPSTREAM IN THE LOW 20S. DRY AIR IS ALSO EVIDENT IN 00Z SOUNDING FROM GSO WHICH SHOWS PRECIPITABLE WATER AROUND 0.20 INCH...WHICH IS ALSO SUPPORTED BY LATEST FORECAST SOUNDINGS SHOWING PRECIPITABLE WATER VALUES BETWEEN 0.15 AND 0.20 INCH BY DAYBREAK. BOUNDARY LAYER WINDS WILL KEEP TEMPERATURES FROM DROPPING WELL BELOW FREEZING...BUT DO THINK MOST OF THE AREA ENDS UP BELOW FREEZING. ONLY SMALL ADJUSTMENTS NEEDED FOR EVENING UPDATE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... AS OF 200 PM THURSDAY...AS HIGH PRESSURE OF CANADIAN ORIGIN BUILDS ACROSS THE CAROLINAS FROM THE W...IT WILL BRING A COLD START TO THE PERIOD. TEMPS AT 850 MB WILL BOTTOM OUT BETWEEN MINUS 4 AND MINUS 7 DEG C. PRECIPITABLE WATER VALUES WILL BE NEAR ONE QUARTER OF AN INCH ON FRI. THIS ALONG WITH STRONG SUBSIDENCE SHOULD SQUELCH CLOUD COVER AND EXPECT A SUNNY DAY FROM BEGINNING TO END. TEMPS WILL ONLY RISE TO THE MID AND UPPER 40S GIVEN THE MAGNITUDE OF COLD AIR IN PLACE... PERHAPS TOUCHING 50 IN A FEW SPOTS DOWN AROUND THE SOUTH SANTEE RIVER. A WEAK DISTURBANCE ALOFT MAY SKIRT THE FORECAST AREA LATE FRIDAY NIGHT. EXPECT ANY CLOUD COVER ASSOCIATED WITH THIS WILL BE BRIEF AND LATE IN ARRIVING. GIVEN HIGH PRESSURE WILL BE BUILDING OVERHEAD AT THE SURFACE AND WINDS WILL BE VIRTUALLY CALM THROUGH THE NIGHT... EXPECT RADIATIONAL COOLING TO QUICKLY DEVELOP AS COLUMN REMAINS VERY DRY. THIS WILL ALLOW LOWS TO DROP TO THE MID AND UPPER 20S. A FEW LOWER 20S WILL BE POSSIBLE IN THOSE TRADITIONALLY COLD SPOTS. HIGH PRESSURE OVERHEAD WILL MOVE OFFSHORE SAT AND SAT NIGHT. THIS WILL ALLOW BOTH TEMPS AND DEWPOINTS TO SLOWLY MODIFY. HIGHS ON SAT WILL RISE TO THE MID AND UPPER 50S AND LOWS SAT NIGHT WILL DROP TO THE MID AND UPPER 30S INLAND WITH LOWER TO MID 40S MORE COMMON AS YOU PROGRESS TO THE COAST. PRECIPITABLE WATER VALUES DO MODESTLY RECOVER TO AROUND A HALF AN INCH...BUT STILL NOT EXPECTING MUCH IN THE WAY OF CLOUDS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 200 PM THURSDAY...MEDIUM RANGE GUIDANCE HAS CHANGED LITTLE WITH REGARDS TO THE EXTENDED PERIOD. THE MID LEVEL PATTERN WILL SHOW A BROAD AND SUBTLE SOUTHWEST FLOW SUNDAY AND MONDAY WITH A SLIGHT SIGNAL FOR A RIDGE MONDAY AS A DEEP AND COLD SHORTWAVE...WHAT IS AN EXTENSION OF THE POLAR VORTEX...THE LOWEST HEIGHTS IN THE NORTHERN HEMISPHERE ROTATE ACROSS CANADA. THE COLD AIR ASSOCIATED WITH THIS FEATURE REACHES OUR AREA IN A MUCH MODIFIED STATE AFTER DROPPING VERY SOUTH IN A BLUE NORTHER IN TEXAS. BY TUESDAY WHEN THE NEW AIRMASS ARRIVES IT WILL ONLY BUMP DOWN TEMPERATURES DOWN FROM THE WARMER 70S...COURTESY OF THE SOUTHWEST FLOW TO UPPER 50S TO NEAR 60. HIGHS WILL BE IN THE 60S WEDNESDAY AND THURSDAY AS ANOTHER WEAK FRONT MOVES ACROSS THURSDAY PREVENTING A MORE SIGNIFICANT WARMUP. NO POPS ASSOCIATED WITH EITHER OF THESE FEATURES. OVERNIGHT LOWS SHOULD STAY ABOVE FREEZING THROUGH THE PERIOD. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... AS OF 00Z...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE TAF PERIOD. STRATOCU IS DIMINISHING IN COVERAGE THIS EVENING...AND MOSTLY CLEAR CONDITIONS WILL PREVAIL TONIGHT WITH NORTHWEST WINDS AOB 10 KT. NO FOG CONCERNS OVERNIGHT AS DRIER AIR FILTERS INTO THE AREA. HIGH PRESSURE WILL CONTINUE RIDGING INTO THE CAROLINAS ON FRI...BRINGING SUNNY SKIES AND NORTH WINDS AROUND 10 KT. COULD BRIEFLY SEE SOME HIGHER GUSTS OF 15 KT ALONG THE COAST AROUND MIDDAY. WINDS WILL SUBSIDE NEAR THE END OF THE PERIOD AS SFC HIGH PRESSURE MOVES OVERHEAD. EXTENDED OUTLOOK...VFR CONDITIONS WILL PREVAIL THROUGH THE WEEKEND. EARLY MORNING FOG POSSIBLE ON MONDAY. MVFR/IFR CIGS WILL DEVELOP ON TUESDAY AS COOL HIGH PRESSURE WEDGES INTO THE CAROLINAS. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 9 PM THURSDAY...ALTHOUGH WIND SPEEDS HAVE BEEN SLOWLY DECREASING THIS EVENING A SURGE IN COLD AIR AROUND MIDNIGHT WILL PUSH WINDS BACK INTO THE 20 TO 25 KT RANGE LATE. AS A RESULT PLAN TO CONTINUE SCA FOR ALL ZONES THROUGH THE OVERNIGHT. DIRECTION WILL BE NORTH TO NORTHWEST WHICH WILL KEEP SEAS WITHIN 20 NM UNDER 6 FT. THE ONLY EXCEPTION COULD BE NEAR THE EASTERN EDGE OF AMZ252 WHICH IS EXPOSED TO EXTENDED FETCH IN NORTH-NORTHWEST FLOW. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 200 PM THURSDAY...HIGH PRESSURE WILL BUILD ACROSS THE WATERS FROM THE WEST ON FRI AND BE CENTERED OVERHEAD FRI AFTERNOON INTO SAT MORNING. THIS HIGH WILL MOVE OFFSHORE SAT AFTERNOON AND NIGHT. THE TIGHTEST PRESSURE GRADIENT AND THUS THE STRONGEST WINDS WILL OCCUR FRI MORNING. SEAS WILL ALSO BE HIGHEST FRI MORNING...SUBSIDING THROUGH THE REMAINDER OF THE PERIOD. MARGINAL SMALL CRAFT ADVISORY CONDITIONS MAY PERSIST TIL AROUND SUNRISE FRI WITH SEAS NEAR 5-6 FT ACROSS THE OUTERMOST WATERS. N WINDS FRI MORNING WILL BE 15 TO AROUND 20 KT. N WINDS OF 10 TO 15 KT FRI AFTERNOON WILL LIGHTEN FURTHER FRI NIGHT. A PERIOD OF LIGHT AND VARIABLE WINDS LATE FRI NIGHT AND SAT MORNING SHOULD SETTLE ON SW SAT AFTERNOON AND NIGHT WITH WIND SPEEDS UP TO 10 TO 15 KT. SEAS OF 3 TO 4 FT FRI AFTERNOON WILL SUBSIDE TO 2 TO 3 FT FRI NIGHT BEFORE STABILIZING IN THAT RANGE THROUGH THE REMAINDER OF THE PERIOD. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 200 PM THURSDAY...A COUPLE OF NICE DAYS FOR THE MARINE COMMUNITY REGARDING WINDS AND SEAS...TEMPERATURES WONT BE TO SHABBY EITHER. ELONGATED HIGH PRESSURE WILL PROVIDE A MODEST SOUTHWEST FLOW SUNDAY AND MONDAY OF BASICALLY TEN KNOTS OR LESS. SEAS WITHOUT ANY SIGNIFICANT SWELL COMPONENT WILL BE 1-3 FEET. THERE MAY BE A DECENT SEA BREEZE MONDAY AS INLAND TEMPERATURES WARM UP TO THE LOWER 70S WITH WATER TEMPERATURES IN THE 50S. A BACKDOOR COLD FRONT WILL MOVE ACROSS MONDAY NIGHT AND TUESDAY WILL FEATURE A MORE BRISK NORTHEAST FLOW OF AROUND 15 KNOTS. SEAS WILL INCREASE TO 3-5 FEET WITH A SMATTERING OF SIX FOOTERS POSSIBLE ACROSS THE OUTERMOST WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...III SHORT TERM...RJD LONG TERM...SHK AVIATION...BJR

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