FXUS62 KILM 232308
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
610 PM EST WED DEC 23 2009
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE CENTERED OVER EASTERN CANADA WILL RIDGE
INTO THE CAROLINAS THROUGH THURSDAY. LOW PRESSURE WILL DEVELOP
OVER THE DEEP SOUTH AND LIFT NORTHEAST ACROSS THE AREA FRIDAY AND
FRIDAY NIGHT...BRINGING A SOAKING RAIN. HIGH PRESSURE WILL BUILD
IN BEHIND THIS STORM SYSTEM...BRINGING FAIR BUT CHILLY WEATHER
SATURDAY THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY/...
AS OF 3 PM WEDNESDAY...A LITTLE MORE ACTIVITY FOR THE NEAR TERM
FORECAST OVERNIGHT AS BOTH THE NAM AND GFS SHOW A SUBTLE COASTAL
TROUGH DEVELOPING VERY LATE. THERE ARE THE USUAL DIFFERENCES AS
THE GFS IS MORE AGGRESSIVE AND CLOSER TO THE COAST. LOOKING AT
SURFACE PRESSURES...1800 UTC READINGS SHOW READINGS FINALLY
STARTING TO FALL AT 41013. THIS TELLS ME ALONG WITH VISIBLE
SATELLITE LOOPS...THE DEVELOPMENT IS LAGGING A BIT. WILL THEREFORE
KEEP THE FORECAST DRY AND ON THE TEPID SIDE OF CLOUD COVER ALONG
THE COAST. CAVEAT FOR OVERNIGHT LOW TEMPERATURE FORECAST IS THE
EXTENT OF HIGH LEVEL MOISTURE SPILLING IN FROM THE WEST. TRENDS
CONTINUE TO SHOW SOME DISSIPATION OF THE MOISTURE AS IT MARCHES
EAST...AND WILL LEAN TOWARD THE COOLER MET NUMBERS WITH THE
EXCEPTION OF CRE WHERE PAST EXPERIENCE LEADS ME TO BELIEVE SOME
COASTAL TROUGH CLOUDINESS MAY KEEP THINGS A BIT WARMER.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...MOTHER NATURE HAS DEFINITELY MISHEARD BING
CROSBY AND WILL BE DELIVERING A WET CHRISTMAS TO THE EASTERN
CAROLINAS. CHRISTMAS EVE LOOKS LIKE A DRY DAY...ALBEIT WITH
INCREASING CLOUDS AS THE WARM ADVECTION ALOFT SETS UP. TEMPS WILL
BE LIMITED BY THAT THICKENING CLOUD DECK...GENERALLY IN THE MID
50S.
POPS WILL INCREASE FROM SW TO NE ON THU NIGHT AS A DEEPENING SE
FLOW MOISTENS THE LOW LEVELS. WILL GRADUALLY RAMP POPS UP TO
LIKELY IN THE WESTERN COUNTIES AND CHANCE ALONG THE NC COAST...BUT
LIMIT THAT MAINLY TO AFTER MIDNIGHT. EXPECT A QUICK DROP IN TEMPS
THU EVENING...THEN LEVELING OFF OR RISING A BIT OVERNIGHT.
BEST LOW-LEVEL MOISTURE FEED WILL BE DURING THE DAY ON
FRIDAY. HEALTHY THETA-E RIDGING AND A 50 KT LOW-LEVEL JET WILL
WARRANT CATEGORICAL POPS. HOWEVER...LIFTED INDICES ON THE ORDER OF
+3 MEAN THE INSTABILITY FOR THUNDER IS LACKING. SHOULD STILL BREAK
FAR ENOUGH INTO THE WARM SECTOR TO REACH AROUND 60 INLAND AND THE
MID 60S NEAR THE COAST.
TIMING OF THE PRECIP SHUTOFF ON FRI NIGHT IS TRICKY. IF
ANYTHING...FAVORED THE FASTER GFS WHICH HAS CHANCE POPS IN THE
EVENING AND ESSENTIALLY NONE AFTER MIDNIGHT. NAM IS QUITE A BIT
SLOWER...KEEPING PRECIP IN FOR MUCH OF THE NIGHT. ALSO LEANED
HEAVILY ON THE COOLER GFS MOS TEMPS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...A SURFACE FRONT WILL BE MOVING OUT OF THE
REGION AS THE DAY STARTS AND THE DRYING TREND FOR THE AREA WILL
BEGIN. AT 500 MILLIBARS THE CLOSED LOW OVER THE WESTERN GREAT LAKES
STATES WILL SLOWLY MOVE EASTWARD NORTH OF THE AREA AND THE TROUGH
AXIS WILL FINALLY SHIFT EAST OUR LONGITUDE BY MONDAY. THUS THE
COOLER THAN NORMAL TEMPERATURES ON MONDAY WILL THEN REBOUND AS THE
FLOW ALOFT BECOMES MORE SOUTHWEST. FOR PRECIPITATION...EXPECT MOST
OF THE PERIOD TO REMAIN DRY. THE MOST UNCERTAINTY WILL BE FOR
WEDNESDAY AS THE 12 UTC GFS IS SHOWING MOISTURE INCREASING FROM A
DEVELOPING LOW IN THE WESTERN GULF OF MEXICO. THE 00 ECMWF IS SLOWER
AND DOES NOT BRING IN THE PRECIPITATION TO THE AREA. SO AT THIS TIME
WILL GO WITH A SILENT 20 POP FOR WEDNESDAY AND HOPE THE UNCERTAINTY
DECREASES WITH TIME.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR EXPECTED THROUGH THE FORECAST PERIOD. MAINLY A CIRRUS CEILING
OVERNIGHT. A MOISTURE AXIS WILL MOVE OVER THE REGION TOMORROW
MORNING...WITH A MODERATE CHANCE OF A STRATA CU CEILING IN THE 4-5K
RANGE. A WEAK WEDGE WILL KEEP NORTHEAST FLOW OVER THE CWA...ALBEIT
LIGHT.
EXTENDED OUTLOOK...MODERATE CONFIDENCE IN PERIODS OF IFR OVERNIGHT
THURSDAY THROUGH EARLY SATURDAY MORNING WITH RAIN AND LOW CEILINGS.
VFR BY MIDDAY SATURDAY THROUGH SUNDAY MORNING. LOW CHANCE OF A MVFR
CEILING SUNDAY AFTERNOON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...HAVE TRIMMED BACK WIND SPEEDS...ESPECIALLY LATE
WHEN THE NAM AND GFS ADVERTISE SUSTAINED WINDS NEARING 20 KNOTS AS
THE GRADIENT INCREASES BETWEEN A COASTAL TROUGH AND HIGH PRESSURE TO
THE NORTH/NORTHWEST. WILL CONTINUE TO ADVERTISE AN INCREASING TREND
FROM AROUND 10 KNOTS TO A RANGE OF 10-15 KNOTS ALTHOUGH SPEEDS WILL
LIKELY BE NEAR THE TOP OF THIS RANGE ESPECIALLY LATE. REGARDING
SEAS...SWAN IS A BIT ON THE HIGH SIDE AS WELL. WILL ADVERTISE 2-3
FEET INITIALLY INCREASING TO 2-4 FEET LATE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...LOOK FOR NE WINDS AND SEAS TO GRADUALLY
INCREASE ON THU AS HIGH PRESSURE HANGS TOUGH TO OUR NORTH...AND
LOW PRESSURE TAKES SHAPE OVER THE DEEP SOUTH. SEAS WILL GRADUALLY
BUILD TO SCA THRESHOLDS BY EARLY AFTERNOON IN THE SOUTHERN
WATERS...AND MID-AFTERNOON IN THE NC WATERS. NOT GOING TO GET TOO
FANCY SO WILL JUST POST THE ADVISORY BEGINNING AT NOON EST
THURSDAY.
COASTAL TROF WILL LOSE THE BATTLE TO STRONG LOW PRESSURE TO OUR
WEST ON THU NIGHT...WITH WINDS VEERING TO EAST AND SEAS
CONTINUING TO BUILD. DECENT LOW-LEVEL JET FRI MORNING WITH 850MB
WINDS REACHING 50 KT...BUT STRONG STABILITY WILL LIMIT SFC WINDS
TO 20-25 KT. SWAN OUTPUT SEEMED THE WAY TO GO...AS THIS WIND
FORECAST UNDERCUTS THE GFS. SEAS GENERALLY MAX OUT AT 6-9 FT EARLY
FRIDAY... AND THEN COME DOWN FRI NIGHT AS WINDS VEER AND DIMINISH
BEHIND THE FRONT.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 3 PM WEDNESDAY...THE LONG TERM PERIOD WILL BEGIN WITH THE
COLD FRONT SHIFTING AWAY FROM THE WATERS. THIS WILL ALLOW FOR AN
OFFSHORE WIND WITH SEAS OF 6 FEET AT THE EXTREME EASTERN SECTIONS
OF THE COASTAL WATERS SATURDAY MORNING. FOR THE REST OF THE
FORECAST PERIOD...SATURDAY NIGHT THROUGH MONDAY...HIGH PRESSURE
WILL BE CENTERED WEST OF THE WATERS AND THE WINDS WILL FLUCTUATE
BETWEEN THE WEST AND NORTHWEST FOR THE REMAINDER OF TIME. WINDS
ARE EXPECTED TO REMAIN AROUND 10 TO 15 KNOTS AND SEAS WILL REMAIN
IN THE 2 TO 4 FT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON THURSDAY TO 6 AM EST SATURDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...SHK
SHORT TERM...RAS
LONG TERM...HAWKINS
AVIATION...43
