000 FXUS62 KILM 100137 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 933 PM EDT FRI MAY 9 2008 .SYNOPSIS... COLD FRONT TRAILING LOW PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE SOUTH ACROSS THE EASTERN CAROLINAS LATE TONIGHT OR EARLY SATURDAY BEFORE STALLING. WEAK HIGH PRESSURE WILL RIDGE ACROSS THE AREA FROM THE NORTH SATURDAY THROUGH EARLY SUNDAY. THE STALLED FRONTAL BOUNDARY WILL RETURN TO THE NORTH AS A WARM FRONT AND CROSS THE REGION SUNDAY MORNING. A MUCH STRONGER COLD FRONT EXTENDING FROM INTENSIFYING LOW MOVING OFF THE VA CAPES...WILL SWEEP ACROSS THE AREA SUNDAY NIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA MONDAY THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 9 PM FRIDAY...00Z SAT MHX SOUNDING INDICATES A CAPPED ATMOSPHERE ACROSS THE EASTERN CAROLINAS...AT AROUND 700MB...AND WITH A LACK OF MOISTURE ABOVE 7H. THE DAYS CU HAVING DEVELOPED BUT WITH THIS ATM PROFILE ILLUSTRATED BY 00Z MHX RAOB...IT MAKES SENSE THAT THE CU FLATTENED OUT ONCE IT REACHED 10K FEET. AM RELUCTANT TO DROP ALL POPS...EVENTHOUGH ITS BASICALLY 20 PERCENT...GIVEN A SFC BOUNDARY BACKDOORING THE AREA OVERNIGHT. THIS BOUNDARY MAY NOT INSTIGATE ENUF FORCE TO BREAK THRU THE 7H LEVEL...HOWEVER ENUF CONVERGENCE AND FORCING CULD AID IN DEVELOPING ISOLATED SHOWERS IN LIEU OF TSTRMS. LATEST 11-3.9 MICRON SAT IMAGERY INDICATES A MSTLY CLEAR SKY ACROSS THE ILM CWA...WITH THIS TREND TO CONTINUE OVERNIGHT. ONLY CLDS TO CONTEND WITH WILL BE PATCHY CONVECTIVE DEBRIS CLOUDS FROM THOSE STORMS ACROSS THE WESTERN CAROLINAS...AND ANY CLOUDS ASSOCIATED WITH THE SFC BOUNDARY DROPPING SOUTH OVERNIGHT. LATEST MIN TEMPS LOOK FINE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...COLD FRONT PUSHES ACROSS THE AREA ON SAT BUT DO NOT EXPECT MUCH IN THE WAY OF CLOUD COVER...LET ALONE PRECIP. MID AND UPPER LEVELS ARE VERY DRY WITH WEST TO NORTHWEST FLOW HELPING TO DRY THINGS OUT EVEN MORE. THERE IS A WEAK SHORT WAVE PASSING TO THE SOUTH IN THE AFTN...BUT MOISTURE STAYS SOUTH AND SOUNDINGS SUGGEST A WEAK MID LEVEL CAP. WENT AHEAD AND PULLED POPS FROM SC AND KEPT NC DRY. TEMPS ABOVE CLIMO CONTINUE...BUT THINK MAV NUMBERS IN THE UPPER 80S FOR MOST SITES ARE A BIT ON THE WARM SIDE. INSTEAD WENT WITH MET/FOUS TEMPS IN THE MID 80S. INCREASING MID AND HIGH CLOUD SAT NIGHT WILL KEEP OVERNIGHT LOWS ABOVE CLIMO DESPITE STRENGTHENING NE FLOW. SUN LOOKS TO BE AN INTERESTING DAY AS THE COLD FRONT THAT PUSHED THROUGH THE AREA ON SAT STARTS TO LIFT BACK N. LATEST NAM/GFS AND EVEN THE CANADIAN DEPICT THE FRONT PUSHING N AS A COMBINATION WARM/OCCLUDED FRONT WITH A TRIPLE POINT LOW DEVELOPING IN THE AFTN. MEASURABLE PRECIP LOOKS LIKE A SURE BET...WENT AHEAD AND RAISED POPS INTO THE 80S. MUCH OF UNCERTAINTY RELATED TO THIS EVENT SURROUNDS WHAT FORM THE PRECIP WILL TAKE. IF LOW FORMS OFF THE COAST ILM FA WILL LIKELY NOT GET INTO THE WARM SECTOR AND NOT HAVE AS MUCH OF A SEVERE WX THREAT. IF SOME OR ALL OF THE CWA IS IN THE WARM SECTOR STRONG LLJ AND STRONG DIVERGENCE ALOFT COULD RESULT IN WIDESPREAD STRONG TO SEVERE STORMS. UNCERTAINTY IN SFC FEATURE POSITIONING ALSO LEADS TO BIG BUST POTENTIAL WITH RESPECT TO TEMPS. FOR NOW GOING MID TO UPPER 70S BUT COULD BE OFF BY ONE OR TWO CATS IF FA IS IN THE WARM SECTOR. PRECIP END SUN EVENING AS DRY SLOT AND UPPER TROF SWING IN. DEVELOPING CYCLONE WILL KEEP BOUNDARY LAYER MIXED HELPING KEEP SUN NIGHT LOWS WARMER THAN WHAT THE 4-6 C 850 TEMPS AND DRYING AIR MASS WOULD SUGGEST. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 3 PM FRIDAY...DRY AND UNSEASONABLY COOL WEATHER FOR THE START OF THE LONG TERM PERIOD. SFC HIGH BUILDING IN WHILE UPPER LOW SHIFTS OFF SHORE WITH DEEP NW FLOW ESTABLISHED LATE MON INTO EARLY WED. TEMPS WILL RUN 5 TO 10 DEGREES BELOW NORMAL MON INTO TUES. BOTH TUES AND WED MORNING WILL SEE MIN TEMPS IN THE 50S WITH 40S IN SOME COOLER SPOTS INLAND. THE BEST CAA WILL TAKE PLACE THROUGH TUES MORNING WITH 850 TEMPS IN THE 3 TO 4 C RANGE...BUT BETTER RADIATIONAL COOLING WILL TAKE PLACE TUES NIGHT INTO WED MORNING WHEN BOTH CLOUDS AND WINDS WILL BE ABSENT. WARMING TREND WILL START WED AS RIDGE BUILDS OVERHEAD BY WED AFTN AND SFC HIGH SHIFTS OFFSHORE WED AFTN INTO THURS WITH WARMER AND MOISTER RETURN FLOW SETTING UP FOR THE LATTER PART OF THE EXTENDED FORECAST. 850 TEMPS REBOUND UP ON WED INTO THURS REACHING 14 TO 15 C BY THURS AFTN. A HIGHER AMPLITUDE TROUGH SETS UP IN THE MID TO UPPER LEVELS AND MOVES ALONG THE EAST COAST HEADING INTO FRI WHILE A COLD FRONT APPROACHES AND CROSSES AREA IN THE LATE THURS INTO FRI TIME FRAME. THEREFORE EXPECTING MORE IN THE WAY OF PCP THURS INTO FRI. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... TRAILING LOW PRESSURE ALONG A WASHED OUT FRONT WILL SHIFT THE WINDS TO THE WEST NORTHWEST OVERNIGHT. ONLY A SLIGHT CHANCE OF FOG...BUT PROBABLY TOO DRY IN THE LOW LAYERS. CONTINUED WEST NORTHWEST FLOW ON SATURDAY WITH VFR CONDITIONS. GRADIENT SATURDAY A BIT WEAKER THAN TODAY...HOWEVER WINDS WILL STILL GUST NEAR 20 KTS BY MIDDAY. GOOD CHANCE OF SHOWERS AND THUNDERSTORMS SUNDAY...WITH INTERMITTENT MVFR/IFR CONDITIONS POSSIBLE...MAINLY DUE TO VISIBILITIES AND CEILINGS FROM CONVECTION. VFR CONDTIONS EXPECTED MONDAY AND TUESDAY. POSSIBLE MVFR/IFR CONDITIONS FROM FOG WEDNESDAY MORNING. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 9 PM FRIDAY...HAVE PUSHED THE SCA TO 3AM SOUTHERN WATERS...AND 9 AM NORTHERN WATERS...MAINLY FOR SEAS. SFC PRESSURE RISES OCCURRING ACROSS THE AREA WATERS...A SIGN THAT THE SYNOPTIC LOW IS FINALLY MOVING FURTHER AWAY FROM THE AREA AND WILL LIKELY HAVE LESS OF AN IMPACT ACROSS THE REGION...VIA WIND-WISE AND ITS RESULTING LOW PERIOD WIND DRIVEN SEAS. 3 HR PRESSURE RISES ARE JUST UNDER 2.0 MB AT THE MOMENT...WITH OVERALL WINDS SW 15-20 KT WITH A FEW HIER GUSTS. AFTER MIDNIGHT...A SFC BOUNDARY TO DROP SOUTH AND BACKDOOR THE AREA BEFORE STALLING SOUTH OF THE AREA WATERS ON SATURDAY. HAVE KEPT ONLY AN ISOLATED CHANCE FOR CONVECTION DUE TO THIS BNDRY. WAVEWATCH3 A BIT UNDERDONE WITH SEA HEIGHTS ACROSS THE ILM WATERS...MEANING IT TRIES TO LOWER THEM TOO QUICKLY. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...COLD FRONT PUSHES OFF THE COAST MIDDAY SAT WITH OFFSHORE FLOW DEVELOPING. INITIALLY FLOW WILL BE LIGHT BUT AS STALLED FRONT TO THE S BEGINS MOVING N WINDS SHIFT TO THE NE AND START TO INCREASE IN SPEED AS GRADIENT TIGHTENS. SPEEDS WILL APPROACH 20 KT WITH SEAS RUNNING 2 TO 4 FT. WINDS BECOME ONSHORE AND INCREASE IN STRENGTH DURING THE DAY SUN AS FRONT MOVES IN AND GRADIENT BECOMES PINCHED. SPEEDS WILL NEAR SCA THRESHOLDS SUN EVENING WITH SEAS SURPASSING 6 FT SUN AFTN. ANTICIPATE SCA BEING ISSUED WITHIN THE NEXT 24 HOURS. WINDS BECOME SW SUN NIGHT IN WAKE OF FRONT WITH SPEEDS 20 TO 25 KT AND SEAS 4 TO 7 FT. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 3 PM FRIDAY...WILL START OUT WITH SCA IN W-NW WINDS ON MONDAY AS HIGH PRESSURE BUILDS INTO LOCAL WATERS BEHIND COLD FRONT. OFF SHORE TRAJECTORY WILL PRODUCE A DECREASING TREND IN SEAS...BUT WILL BE SLOWER TO DIMINISH...ESPECIALLY OFF SHORE WITH GOOD DEAL OF CAA TO KEEP A WELL MIXED BOUNDARY LAYER THROUGH MON. WINDS AND SEAS SHOULD DROP BELOW SCA THRESHOLDS BY EARLY TUES MORNING AND WILL CONTINUE DECREASING AS HIGH PRESSURE MOVES OVERHEAD WITH WEAK GRADIENT FLOW EXPECTED FOR TUES INTO WED. WINDS WILL SHIFT AROUND FROM THE NW MON AFTN TO N-NE BY WED MORNING. SEAS SHOULD BE DOWN TO THE 2 TO 4 FT RANGE BY TUES AND SEAS 3 FT OR LESS TUES NIGHT INTO WED. HIGH PRESSURE WILL SHIFT OFF SHORE BY WED AFTN WITH A SOUTHERLY RETURN FLOW SETTING UP. GRADIENT REMAINS RELATIVELY WEAK UNTIL THURS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EDT SATURDAY FOR AMZ254-256. ...SMALL CRAFT ADVISORY UNTIL 9 AM EDT SATURDAY FOR AMZ250-252. && $$ SYNOPSIS...HOEHLER/ARMSTRONG NEAR TERM...HOEHLER SHORT TERM...LEBO LONG TERM...ZOUZIAS AVIATION...LOEWENTHAL