FXUS62 KMHX 240158
AFDMHX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
858 PM EST WED DEC 23 2009
.SYNOPSIS...
STRONG HIGH PRESSURE IS RIDGING FROM THE GREAT LAKES SOUTH TO
FLORIDA. THIS HIGH WILL SHIFT OFFSHORE AS A WARM FRONT MOVES NORTH
ACROSS THE REGION CHRISTMAS DAY. A COLD FRONT WILL THEN MOVE
ACROSS THE AREA AND OFFSHORE BY EARLY SATURDAY. HIGH PRESSURE WILL
THEN BUILD INTO THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 730 PM WEDNESDAY...REINFORCING HIGH PRESSURE TO THE NORTH
WILL CONTINUE TO RIDGE SOUTH INTO NC OVERNIGHT. MEANWHILE HIGH
CLOUDINESS UPSTREAM ASSOCIATED WITH COMPLEX LOW PRESSURE OVER THE
THE SOUTHERN PLAINS WILL STREAM INTO EASTERN NC BECOMING MORE
OPAQUE WITH TIME. THIS THICKENING CLOUD COVER WILL EVENTUALLY
HAVE AN AFFECT ON RADIATIONAL COOLING WHICH WILL BE MAXIMIZED THIS
EVENING. WITH LESS COOLING EXPECTED OVERNIGHT FORECAST LOWS IN THE
NWP GUIDANCE ARE A FEW DEGREES WARMER THAN PREVIOUS NIGHTS WITH
LOWS 29-33 DEGREES EXPECTED. EXPECTING NO SIGNIFICANT CHANGES TO
ONGOING FORECAST.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
AS OF 2 PM WEDS...STRONG HIGH PRESSURE WILL GRADUALLY WEAKEN AND
SHIFT OFFSHORE BY LATE THURSDAY. MOISTURE INCREASES TOMORROW FROM
THE SOUTH AND WEST AHEAD OF NEXT SOUTHERN STREAM SYSTEM. WITH LOW-
LEVEL FLOW BECOMING MORE EASTERLY THURSDAY NIGHT AS
MOISTURE/ISENTROPIC LIFT INCREASES...WILL SEE LOW CLOUDS INCREASE
WHICH WILL HOLD MIN TEMPS IN THE LOWER AND MIDDLE 40S. GOOD
AGREEMENT BETWEEN THE GFS AND ECMWF CONTINUES WHILE THE NAM12 IS
SLOWER WITH THE ONSET OF THE PRECIP ON FRIDAY. HAVE LEANED TOWARD
THE GFS/ECMWF AND WILL START TO BRING IN SMALLISH POPS FROM THE
SOUTHWEST EARLY FRIDAY MORNING WITH HIGH LIKELY TO CATEGORICAL
POPS SPREADING ACROSS THE ENTIRE CWA DURING THE AFTERNOON AND
EVENING. PER THE GFS/ECMWF SOLUTION...MOST OF THE PRECIP WILL BE
OFFSHORE BY 12Z ON SATURDAY. QPF TOTALS NOW LOOK A BIT
HIGHER...GENERALLY IN THE INCH TO INCH AND A HALF RANGE FOR THIS
SYSTEM. WITH LEADING WARM FRONT MOVING NORTH OF THE AREA ON
FRIDAY...WILL SEE MAX TEMPS RISE INTO THE LOWER AND POSSIBLY
MIDDLE 60S FRIDAY. FOR FRIDAY NIGHT...TRENDED TOWARD THE COOLER
GFS GUIDANCE. SATURDAY STILL LOOKS MILD AHEAD OF THE STRONGER COLD
FRONT WITH MAXES APPROACHING 60 OVER MANY AREAS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 2 PM WEDS...STRONG COOL HIGH PRESSURE WILL BUILD OVER THE
EASTERN UNITED STATES FOR THE SUNDAY THROUGH TUESDAY PERIOD. TEMPS
WILL REMAIN BLO NORMAL WITH MAXES IN THE UPPER 40S AND LOWER 50S
AND MINS MAINLY IN THE 30S. THE ECMWF AND GFS ARE HINTING AT WEAK
LOW PRESSURE POSSIBLY PRODUCING PRECIP ON WEDS BUT WITH LITTLE
RUN-TO-RUN CONTINUITY...WILL KEEP THE FORECAST DRY FOR NOW.
WITH THE CONTINUED NORTH ATLANTIC OSCILLATION (NAO) AND STRONG
RIDGING OVER THE WESTERN UNITED STATES...SUPPORTED BY THE MJO
PULSE IN PHASES 8, 1 AND 2 OVER THE NEXT COUPLE OF WEEKS...ANTICIPATE
A COLD AND SOMEWHAT STORMY PATTERN CONTINUING OVER THE EASTERN
UNITED STATES IN MID JANUARY.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 730 PM WEDNESDAY...MAIN QUESTION TONIGHT REVOLVES AROUND FOG
POTENTIAL. LAST 2 NIGHTS KPGV/KEWN HAVE BEEN PLAGUED WITH STEAM
FOG DUE TO THE VERY COLD AIR IN PROXIMITY TO WARMER BODIES OF
WATER. TONIGHT DEWPOINTS ARE HIGHER THAN PREVIOUS EVENINGS AND
WITH RADIATIONAL COOLING TEMP/DEWPOINT DEPRESSIONS HAVE BEEN
NARROWING. BANKING ON ADVANCING HIGH CLOUDS BECOMING
OPAQUE AND PREVENTING READINGS FROM REACHING THE CROSS OVER
TEMPERATURES IN THE UPPER 20S. WILL FORECAST MVFR VISIBILITIES AT
KPGV/KEWN BASED ON PERSISTENCE BUT HOLD OFF ON IFR FOR NOW. IN
ADDITION THE BL FLOW IS FORECAST TO INCREASE WITH REINFORCING HIGH
PRESSURE BUT NOT SURE IF WINDS BENEATH THE NOCTURNAL INVERSION
WILL RESPOND.
VFR EXPECTED TO CONTINUE THROUGH THU EVENING. HOWEVER...AS LOW
LEVELS CONTINUE TO SATURATE WITH ONSHORE FLOW COULD SEE SOME MVFR
CIGS BY LATE THU NIGHT. FURTHER DETERIORATING CONDITIONS EXPECTED
THROUGH THE DAY ON FRI AS FRONTAL SYSTEM APPROACHES FROM THE W.
PREDOMINANT MVFR APPEARS LIKELY WITH OCCN IFR AS PRECIP MOVES IN
BY FRI AFTN AND CONTINUES INTO THE EVENING HOURS. STRONG AND GUSTY
SE WINDS ALSO EXPECTED TO BE AN ISSUE ON FRI. CONDITIONS IMPROVE
TO VFR BY SAT MORNING AS FRONT PUSHES OFFSHORE. MAINLY VFR TO
PERSIST INTO EARLY NEXT WEEK WITH BUILDING HIGH PRES AND
PERSISTENT WLY WINDS.
&&
.MARINE...
AS OF 900PM WEDNESDAY...N/NE WINDS 5-15KT AND SEAS MAINLY 3FT OR
LESS ARE RULING THIS EVENING WITH WEAK HIGH PRES SE VIRGINIA.
STILL LOOKS LIKE NE WINDS WILL PICK UP A NOTCH LATE TONIGHT INTO
THU AS REINFORCING HIGH PRES BUILDS IN FROM THE NORTH...AND
INTERACTS WITH WEAK COASTAL TROUGHING OFF THE SE COAST. SWAN STILL
SUGGESTS THIS WILL ALLOW SEAS TO BUILD TO SCA LEVELS TOMORROW MAINLY
BEYOND 10NM. WHILE IT LOOKS MARGINAL HAVE LEANED TOWARDS THE SIDE OF
CAUTION AND ISSUED THE ADVISORY AS WAVE PERIODS WILL BE VERY SHORT
WITH ASSOCIATED HIGH STEEPNESS. CONDITIONS STILL EXPECTED TO
DETERIORATE FURTHER FROM SOUTH TO NORTH THU NIGHT AND ESP CHRISTMAS
DAY AS FRONTAL SYSTEM NEARS FROM THE W/SW. HAVE LEANED TOWARDS THE
ECMWF/GFS SOLUTIONS AS NAM SEEMED TO BE A MUCH SLOWER OUTLIER WITH
MOVING THE FRONT OFFSHORE SAT EVENING. BLENDING THESE SOLUTIONS WITH
PREVIOUS FORECAST GAVE STRONG SMALL CRAFT TO NEAR GALE RANGE SE
BECOMING S WINDS LATE FRI AFTN THROUGH FRI NIGHT. ALSO ADVERTISING
SCA WINDS FOR THE SOUNDS BUT HAVE NOT ISSUED THE ADVISORY THERE YET
SINCE ITS 4TH PERIOD. SEAS EXPECTED TO PEAK IN THE 10-13FT RANGE FRI
NIGHT.
IT THEN LOOKS LIKE 10-20 KT WLY WINDS THROUGH THE END OF THE WEEKEND
AS HIGH PRES BUILDS IN FROM THE GULF COAST STATES. BOTH GFS AND
ECMWF ARE SHOWING SMALL CRAFT W/NW WINDS EARLY NEXT WEEK THOUGH AS
THE HIGH GETS REINFORCED FROM THE CENTRAL CONUS...AND LOW PRES
DEEPENS NEAR THE GULF OF MAINE. HAVE CONTINUED TO SHOW A MODEST
INCREASE IN WIND SPEEDS AT THIS JUNCTURE THOUGH. SE BECOMING S WIND
WAVES COME DOWN STEADILY THROUGH THE WEEKEND...BUT GET REPLACED BY A
MIX OF SHORT PERIOD W WIND WAVES AND LONG PERIOD E/NE SWELL FROM LOW
PRES EAST OF THE CANADIAN MARITIMES. THIS WILL LIKELY ALLOW SMALL
CRAFT RANGE SEAS TO PERSIST THROUGH MUCH OF THE WEEKEND...ESP WATERS
NORTH OF OCRACOKE.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THURSDAY TO 3 PM EST SUNDAY FOR
AMZ150-152-154.
SMALL CRAFT ADVISORY FROM 4 PM THURSDAY TO 4 AM EST SUNDAY FOR
AMZ156-158.
&&
$$
SYNOPSIS...CTC/JME
NEAR TERM...JME
SHORT TERM...CTC
LONG TERM...CTC
AVIATION...JME/MW
MARINE...MW/BM
