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. --
000 FXUS62 KILM 220824 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 324 AM EST SAT NOV 22 2014 .SYNOPSIS...
-- Changed Discussion --
CLOUDS WILL SLOWLY INCREASE TODAY WITH TEMPERATURES REMAINING COOL. A DEVELOPING STORM SYSTEM BREWING IN THE GULF OF MEXICO WILL LIFT NORTHEAST BRINGING MUCH MILDER TEMPERATURES SUNDAY AND MONDAY...ALONG WITH UNSETTLED AND WET WEATHER. ANOTHER SYSTEM WILL BRING ANOTHER ROUND OF RAIN BY MIDWEEK WITH CONDITIONS DRYING OUT BY THE END OF THE WEEK.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 930 PM FRIDAY...TEMPERATURES CONTINUE ON A STEADY DECLINE THIS EVENING. STILL EXPECTING A CLEAR AND COLD OVERNIGHT PERIOD. PREVIOUS DISCUSSIONS FOLLOW: NO SURPRISES WITH THE LATEST UPDATE. HAVE TWEAKED THE GRIDDED DATABASE TO ALTER THE TEMPERATURE CURVE TO SHOW A SLOWER EVENING COOL-DOWN. OTHERWISE FORECAST REMAINS UNCHANGED WITH CLEAR SKIES AND MOST PLACES SEEING BELOW FREEZING TEMPERATURES BY DAYBREAK ON SATURDAY. PREVIOUS DISCUSSION FOLLOWS: A LARGE AREA OF HIGH PRESSURE WILL BE COVERING JUST ABOUT THE EASTERN HALF OF THE COUNTRY THROUGH THE PERIOD. WHILE A CHILLY AIRMASS IT IS NOT OF POLAR ORIGIN AS SOME OF OUR RECENT COLD SNAPS HAVE BEEN. ANOTHER SAVING GRACE FOR THOSE WHO ARE NOT A BIG FAN OF THE COLD IS THAT RADIATIONAL COOLING WILL NOT BE MAXIMIZED DUE TO A LIGHT NE WIND THAT WILL PERSIST INTO THE LATE PART OF THE OVERNIGHT HOURS. THIS IS ILLUSTRATED IN NOT ONLY THE TIGHTLY CLUSTERED MOS GUIDANCE BUT ALSO IN FORECAST MODEL SOUNDINGS. FORECAST SOUNDINGS SHOW A NEARLY ISOTHERMAL LAYER DEVELOPING THROUGH ABOUT 4-5KFT RATHER THAN A SHARP SURFACE-BASED INVERSION AS USUALLY SEEN IN BITTERLY COLD AND SHALLOW ARCTIC AIR. EVEN SO TEMPERATURES WILL GET DOWN INTO THE MID 20S NW TO LOW 30S SE. AGAIN NOT ARCTIC BUT STILL A SOLID 10 DEGREES BELOW CLIMO. CLEAR SKY EXPECTED WITH NOT ONLY A VERY DRY SURFACE AIRMASS BUT ALSO A DRY WESTERLY FLOW ALOFT. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
-- Changed Discussion --
AS OF 330 AM SATURDAY...POTENT STORM SYSTEM...NOW SEEN ON IR SATELLITE IMAGERY MOVING ACROSS TEXAS WILL BRING A SIGNIFICANT RAIN EVENT TO THE AREA SUNDAY. THIS SYSTEM WILL MOVE UP INTO THE MISSISSIPPI VALLEY AND SHEAR OUT BUT COPIOUS MOISTURE NOW SEEN POOLING IN THE GULF OF MEXICO WILL BE DRAWN NORTHWARD IN A ORGANIZED FASHION. A LITANY OF FORCING MECHANISMS WILL BE WORKING IN TANDEM INCLUDING A DIFFUSE WARM FRONT AND SPEED CONVERGENCE FOR THE LOWER LEVELS AND MID AND UPPER LEVEL DIFLUENCE. LONG STORY SHORT...I HAVE ELEVATED POPS TO 100 ACROSS THE BOARD FOR LATE SUNDAY MORNING THROUGH THE EVENING HOURS. THE NAM IS A LITTLE FASTER MOVING THE SYSTEM THROUGH BUT OPTED FOR THE GFS SOLUTION CITING THE CONSISTENCY. SEVERE THREAT PARAMETERS REMAIN UNCHANGED...A LOT OF SHEAR AND LOW LEVEL HELICITY BUT THE INSTABILITY REMAINS IN QUESTION. SPC HAS NOW MOVED ALL AREAS OF THE CWA INTO A SLIGHT RISK WITH THE DAY TWO OUTLOOK. TEMPERATURE FORECAST REMAINS IN PLACE MOST NOTABLY THE EXPECTATION OF UPPER 70S MONDAY COURTESY OF THE STRONG SOUTHWEST FLOW THAT REMAINS IN PLAY...THIS DESPITE OVERCAST SKIES WITH LOWER CEILINGS.
-- End Changed Discussion --
&& .LONG TERM /TUESDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 330 AM SATURDAY...MEDIUM RANGE GUIDANCE IS NOW COMING INTO BETTER AGREEMENT AT LEAST FOR THE FIRST COUPLE DAYS OF THE EXTENDED. A SECONDARY DEEP AND PROGRESSIVE SHORTWAVE DIVING INTO THE LOWER MISSISSIPPI VALLEY ONCE ACTS ON ABUNDANT MOISTURE FROM THE GULF OF MEXICO PAINTING ANOTHER WET SCENARIO FOR LATE TUESDAY AND WEDNESDAY. THE GUIDANCE HAS BEEN OFF AND ON THE PAST FEW DAYS WITH THIS SCENARIO BUT WITH BOTH THE GFS AND 0000 UTC ECMWF DEVELOPING RAIN WELL INLAND...CONFIDENCE IS HIGHER. THE PRIMARY FORCING WILL BE THE RIGHT ENTRANCE REGION OF THE 200-300 JET MOVING SLOWLY SOUTH TO NORTH ALONG THE COAST. I HAVE INCREASED POPS TO LIKELY FOR WEDNESDAY BUT SUBSEQUENT SHIFTS MAY WANT TO INCREASE TO CATEGORICAL IN SHORT ORDER. BEYOND THIS...A LITTLE BETTER AGREEMENT AS WELL WITH A BROAD TROUGH ENVELOPING THE EASTERN THIRD OF THE U.S WITH HIGH PRESSURE AT THE SURFACE.
-- End Changed Discussion --
&& .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... AS OF 06Z...HIGH CONFIDENCE FOR VFR THRUOUT THE VALID ISSUANCE PERIOD. THE ELONGATED CENTER OF 1030+ MB HIGH PRESSURE WILL LIE NEARLY OVERHEAD TODAY...WITH CONTINUED SUBSIDENCE AFFECTING THE LOCAL TERMINALS. VARIOUS MODEL SOUNDINGS FOR LOCAL TERMINALS INDICATE A VERY DRY AIRMASS TO AFFECT THE FA...WITH PWS LESS THAN ONE-QUARTER OF AN INCH. BY LATE TODAY THRU TONIGHT...LOW LEVEL WINDS VEER WITH HEIGHT. THE SC FIELD JUST OFFSHORE...MAY GET DRAWN ACROSS THE COASTAL TERMINALS LATER TONIGHT JUST BEYOND THE 06Z ISSUANCE PERIOD. OTHERWISE...LOOKING AT SKC CONDITIONS. WINDS GENERALLY BELOW 10 KT THRUOUT THE 06Z PERIOD...AND MAY BECOME VARIABLE IN DIRECTION AT LESS THAN 3 KT DUE TO THE CENTER OF HIGH PRESSURE OVERHEAD. EXTENDED OUTLOOK...MVFR/IFR CIGS AND VSBY BY SUNDAY AFTERNOON AND CONTINUING THRU SUNDAY NIGHT. THIS DUE TO STRATIFORM RAINS AHEAD OF A WARM FRONT BECOMING CONVECTIVE IN NATURE AFTER THE WFP SUNDAY NIGHT INTO MON. FOR TUESDAY VFR INLAND TERMINALS WITH MVFR/-RA COASTAL TERMINALS. FOR WEDNESDAY MVFR/-RA EARLY WITH VFR THRUOUT LATER IN THE DAY. && .MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM FRIDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSIONS FOLLOW: BASED ON LATEST OBS AND GUIDANCE HAVE INITIALIZED SEAS DOWN BY ABOUT A FOOT. OBS NOW SHOW MOST PLACES OVER THE COASTAL WATERS IN THE 2 TO 3 FT RANGE...WITH PERHAPS SOME 4 FOOTERS OVER OUR SOUTH CAROLINA MARINE ZONES. THESE CONDITIONS WILL PERSIST OVERNIGHT. PREVIOUS DISCUSSION FOLLOWS: THE AREA REMAINS IN THE GRIP OF A SURGE OF COLD AIR. IT IS NOT ARCTIC AIR AND THEREFORE THE SURFACE PRESSURE ASSOCIATED WITH THE AIRMASS (CENTERED JUST TO OUR NORTH) WILL NOT BE AS HIGH. AS SUCH WE WILL NOT SEE ANY ADVISORIES OR EVEN 5 FT CAUTIONARY HEADLINE- NECESSITATING SEAS. MODERATE NE WINDS HEADING INTO TONIGHT WILL RELAX AS THE NIGHT WEARS ON...TO THE TUNE OF ABOUT A CATEGORY. SEAS MAINLY ABATE ALONG THE OUTER REACHES OF THE FORECAST ZONES IN THE STRONGLY OFFSHORE FLOW. THAT IS NEARER TO SHORE THE DECREASE IN SEAS WILL BE LESS NOTICEABLE DUE TO WAVE SHADOWING. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 330 AM SATURDAY...BASED ON MODEL CONSISTENCY...WILL RAISE A SMALL CRAFT ADVISORY FOR ALL WATERS BEGINNING SUNDAY MORNING AND CONTINUING THROUGH TUESDAY AM. THIS AS A POTENT STORM SYSTEM AFFECTS THE SOUTHEAST. WINDS WILL QUICKLY RAMP UP FROM THE SOUTHEAST TO 20-25 KNOTS AND EVEN A LITTLE HIGHER SUNDAY AFTERNOON FOR A BRIEF PERIOD. WARM AIR ADVECTION AND LIMITED CONVECTIVE MIXING PROBABLY KEEPS A GALE WARNING OUT OF PLAY AS THE WINDS OFF THE DECK ARE QUITE STRONG. THIS WILL QUICKLY BUILD SEAS TO 5-8 FEET. THE WINDS WILL DIMINISH SLIGHTLY FOR MONDAY AND VEER TO THE SOUTHWEST BUT REMAIN SUFFICIENTLY STRONG...AROUND 20 KNOTS TO KEEP SEAS WORKED UP. A WEAKER WESTERLY FLOW SHOULD FINALLY GIVE MARINERS A BRIEF BREAK BEGINNING TUESDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 330 AM SATURDAY...RELATIVELY LIGHT WIND FIELDS TUESDAY AS WEAK HIGH PRESSURE BUILDS IN BRIEFLY. BY WEDNESDAY AN ELONGATED LOW DEVELOPS AND MOVES WELL OFFSHORE BUT IS ENOUGH TO GIVE MORE CONSISTENCY TO THE WIND DIRECTION...NORTH...NORTHEAST. SPEEDS WILL INCREASE TO 20-25 KNOTS AS WELL. SEAS WILL DIP TO A RANGE OF 2-4 FEET TUESDAY AND BUILD ONCE AGAIN WITH THE INCREASE IN WINDS WEDNESDAY.
-- End Changed Discussion --
&& .ILM WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 7 AM EST TUESDAY FOR AMZ250-252-254-256.
-- End Changed Discussion --
&& $$ SYNOPSIS...SHK NEAR TERM...REK SHORT TERM...SHK LONG TERM...SHK AVIATION...DCH/MAC

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