FXUS62 KILM 061913
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
213 PM EST SUN DEC 6 2009
.SYNOPSIS...
A COASTAL TROUGH WILL DEVELOP AND BRING MOISTURE TO THE REGION
THROUGH MONDAY. A MORE SIGNIFICANT STORM SYSTEM WILL AFFECT THE
AREA LATE TUESDAY INTO WEDNESDAY. UNSETTLED WEATHER MAY RETURN FOR
NEXT WEEKEND FOLLOWING A COUPLE OF DRY DAYS THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2:30 PM SUNDAY...IMAGES FROM SPACE THIS AFTERNOON SHOW
FRACTURED SHEETS HIGH CLOUDS STREAMING SW TO NE OVER MUCH OF THE
GULF COAST STATES INTO THE MID ATLANTIC...ASSOCIATED WITH AN ACTIVE
SOUTHERN BRANCH AHEAD OF SHORT-WAVE ENERGY TRACKING OVER THE WESTERN
GULF OF MEXICO THIS AFTERNOON. A STRATOCUMULUS FIELD HAD FOUND ITSELF
BANKED UP AGAINST THE EASTERN 1/3 OF THE FORECAST AREA ASSOCIATED
WITH LOW LEVEL NE WINDS...WET GROUNDS...AND A LITTLE LOW ANGLE SUN
HELPING TO COOK UP THE CUMULUS. THIS HAS KEPT LOCAL MAXIMUM TEMPS
HELD IN CHECK BELOW 50 DEGREES ACROSS THE EASTERN SECTOR THIS CHILLY
AFTERNOON.
LATEST OFFSHORE ISOBARIC ANALYSIS REVEALS PRESSURE FALLS WORKING
STEADILY TOWARD SHORE ALONG AND AHEAD OF A BAROCLINIC ZONE BEYOND
THE 0-20NM WATERS. THIS FEATURE COUPLED WITH SHORTWAVE ENERGY
SCHEDULED TO APPROACH THE REGION FROM THE SW THIS EVENING WILL AID
IN WEAK COASTAL TROUGH DEVELOPMENT OVERNIGHT. THE QUESTION CRITICAL
TO THE NEAR TERM FORECAST REMAINS...HOW CLOSE TO SHORE WILL THIS
AXIS PUSH...AND WILL IT AID IN SHOWER DEVELOPMENT ALONG THE COASTAL
ZONES LATE TONIGHT INTO EARLY MONDAY? COMPARING THE NAM AND GFS IT
IS EVIDENT THE NAM KEEP THE AXIS WELL OFFSHORE WITH NO MEASURABLE
RAINFALL OVER LAND...WHILE THE GFS SPREADS LIGHT BUT WIDESPREAD RAIN
OVERTOP THE COLD AIR WEDGE THAT WILL HOLD THROUGH THE NEAR TERM.
ADMITTEDLY NOT A GOOD FEEL WITH EITHER SCENARIO BUT WILL OPT FOR A
MIDDLE ROAD SOLUTION AND INTRODUCE LIGHT MEASURABLE RAIN ALONG THE
COAST WITH TRACE AMOUNTS A LITTLE FARTHER INLAND LATE TONIGHT.
OVERNIGHT TEMPS WILL LIKELY BECOME PROBLEMATIC IN ADHERING TO A
NORMAL DIURNAL TEMP CURVE...WITH DECENT RADIATIONAL COOLING THROUGH
EVENING...BUT CLOUD COVER PROBABLE LATE TONIGHT AS THE WEDGE HOLDS
AND THE COASTAL TROUGH AXIS NEARS. THUS WE MAY SEE THE TEMP CURVE
LEVEL OFF LATE TONIGHT WITH OVERCAST ONSET...AND MOST FAVORED ALONG
THE COAST. FOR LOWS WILL SHOOT MAINLY FOR 30S AREA WIDE...BUT SOME
ADJUSTMENTS UPWARD OVER THE EASTERN CWA MAY BE REQUIRED IF CLOUDS
DEVELOP OVER LAND AS SOON AS THIS EVENING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 2:30 PM SUNDAY...BROAD WEST TO SOUTHWEST FLOW WILL CONTINUE
THROUGH THE PERIOD AT THE MID LEVELS WITH A COUPLE OF SYSTEMS TO
CONTEND WITH. THE LATTER BEING THE MORE SIGNIFICANT SYSTEM. FOR
MONDAY...A COASTAL TROUGH WILL DEVELOP OR PERSIST AS THERE ARE
INDICATIONS THIS FEATURE IS DEVELOPING NOW. THE GFS IS ADVERTISING
POPS ACROSS MOST OF THE AREA VIA ISENTROPIC LIFT ON THE 300K
SURFACE. THE NAM CONTINUES TO KEEP THE ACTIVITY MOSTLY OFFSHORE
WITH A LITTLE QPF RIGHT ALONG THE COAST. FEEL THE GFS IS A BIT
OVERDONE AND LEANING TOWARD THE NAM GIVES YIELDS GOOD FORECAST
CONTINUITY. A COMPLEX STORM SYSTEM TAKES SHAPE TUESDAY IN THE
CENTRAL U.S. VIA A POTENT JET STREAK MOVING THROUGH THE
WESTERLIES. FOR OUR AREA...THE WARM FRONT MOVES ACROSS LATE
TUESDAY AND INTO WEDNESDAY MORNING. WILL LEAN TOWARD THE WETTER
GFS FOR THIS SYSTEM AND MAINTAIN THE LIKELY POPS FOR ALL AREAS.
REGARDING SEVERE POTENTIAL...THERE IS SOME SHEAR AVAILABLE WITH
WELL OVER 40 KNOTS OF 0-6KM BULK SHEAR BUT AS USUAL...CAPES REMAIN
OFFSHORE FOR THE MOST PART.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 2:30 PM SUNDAY...VERY STRONG WIND FIELDS AT ALL LEVELS WILL BE
PUSHING DEEP MOISTURE OFF THE COAST AT THE START OF THE PD. WHAT
MAY START OUT WED MORNING AS PRETTY GOOD RAIN CHANCES WILL QUICKLY
TAPER OFF FROM W TO E. THE COLD FRONT MAY LAG A FEW HOURS LEADING
TO REALLY ALIGNED SOUTH-SOUTHWESTERLY FLOW THAT COULD OPTIMIZE
MIXING OF MOMENTUM FOR SOME PRETTY STRONG WIND GUSTS. BY
EVENING/EARLY THURSDAY NIGHT THE WIND SHIFT TO WEST AT THE SURFACE
CUTTING DOWN ON THE GUSTINESS BUT STILL RATHER BREEZY THROUGH THE
NIGHT. CAA STRONGEST THURSDAY NIGHT INTO FRIDAY MORNING. THIS
QUICKLY REVERSES TO OVERRUNNING WAA LATER FRIDAY AS SOUTHERN
BRANCH BRINGS A FLAT WAVE ACROSS THE GOMEX AND JUST OFF THE S
CAROLINA COAST BY SATURDAY. COLD AIR WEDGING SETS UP ON SUNDAY
WITH A DEVELOPING SFC TROUGH WELL OFFSHORE.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR/MVFR CEILING NEAR THE COAST EARLY...OTHERWISE VFR THROUGH
TONIGHT. A WEAK WEDGE SETS UP OVERNIGHT...WITH AND THE TIME HEIGHT
SHOWS CEILINGS LOWERING TO MVFR AFTER SUNRISE. NORTHEAST FLOW
THROUGH THE PERIOD...A BIT MORE EAST NORTHEAST MONDAY.
EXTENDED OUTLOOK...IFR EXPECTED TUESDAY NIGHT AND WEDNESDAY WITH
RAIN AND SHOWERS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2:30 PM SUNDAY...STEADY AND MODERATE NE WIND FLOW IS EXPECTED OVER
NIGHT WHICH SHOULD KEEP SEAS RUNNING 3 TO 4 FEET THROUGH THE NEAR
TERM PERIOD...WITH ISOLATED 5 FOOTERS POSSIBLE FAR OUTER
PORTION...AND 2 FOOT SEAS NEAR SHORE SOUTH OF CAPE FEAR AND NORTH OF
MURRELLS INLET TONIGHT. DOMINANT WAVE PERIODS WILL BE RUNNING IN THE
5 TO 6 SECOND RANGE IMPLYING A MODERATE STEEPNESS TO THE SEA HGHTS.
DEPENDING HOW CLOSE OR FAR THE TROUGH AXIS CAN GET INTO THE 0-20 NM
WATERS WILL HAVE AN EFFECT ON WINDSPEEDS. IF THE GFS PROVES CORRECT
IN BRINGING THE AXIS CLOSEST...AN EXERCISE CAUTION STATEMENT COULD
BE NEEDED LATE TONIGHT INTO EARLY MONDAY FOR BEEFIER NE WIND FLOW.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 2:30 PM SUNDAY...WINDS WILL REMAIN FROM THE NORTHEAST FOR THE
MOST PART THROUGH TUESDAY. THE ONLY CAVEAT TO THIS IS THE
PROGRESSION OF THE COASTAL TROUGH MONDAY WHEN THE FEATURE MAY
BRIEFLY DISTORT DIRECTIONS BEFORE MOVING OFF TO THE NORTHEAST.
SPEEDS WILL BE IN A 10-15 KNOT RANGE. A SIGNIFICANT WIND SHIFT
OCCURS LATE TUESDAY INTO WEDNESDAY MORNING AS A WARM FRONT MOVES
ACROSS THE WATERS. THIS WILL SHIFT WINDS TO SOUTHEAST WITH SPEEDS
IN A RANGE OF 15-20 KNOTS. SEAS WILL REMAIN IN A MODEST RANGE WITH
2-4 FEET THROUGH TUESDAY EVENING INCREASING TO 3-5 FEET BY
WEDNESDAY MORNING AS THE SOUTHEAST FLOW INCREASES.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 2:30 PM SUNDAY...WEDNESDAY BEGINS WITH A PREFRONTAL WARM
ADVECTION REGIME THAT WILL BE STRONG ENOUGH TO REQUIRE A SMALL
CRAFT ADVISORY IF NOT A GALE WARNING. COLD FRONT DUE LATE WED
EVENING OR EARLY THURSDAY NIGHT. WIND SHIFT WILL BE FOLLOWED BY
DECREASING WINDS BUT FLAGS WILL STILL BE FLYING AS ABATEMENT OF
SEAS LAGS A BIT. IMPROVEMENT WILL BE MORE PRONOUNCED ON THURSDAY
AS HIGH PRESSURE BUILDS IN FROM THE WEST RELAXING THE GRADIENT
CONSIDERABLY. HIGH PRETTY CLOSE FOR MOST OF FRIDAY KEEPING LIGHT
WINDS BUT A DEVELOPING TROUGH OFF THE COAST MAY ALREADY START TO
TIGHTEN THE GRADIENT FRIDAY NIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...DL
