000
FXUS62 KCHS 062059
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
359 PM EST TUE JAN 6 2009

.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH ON WEDNESDAY...THEN A SECONDARY
FRONT WILL MOVE THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL
DOMINATE THROUGH SATURDAY...THEN ANOTHER FRONT WILL AFFECT THE
AREA SUNDAY. HIGH PRESSURE WILL BUILD IN THROUGH TUESDAY.

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A STRONG COLD FRONT WILL APPROACH THE AREA FROM THE WEST LATE
TONIGHT. AHEAD OF THE FRONT...A POTENT LOW-LEVEL JET IS EXPECTED
WITH 925 MB WINDS APPROACHING 60 KT BY 12Z WED. SIGNIFICANT CLOUD
COVER AND WARM ADVECTION WILL KEEP TEMPS FROM DROPPING MUCH BELOW
60F. THUS GUSTY WINDS SHOULD DEVELOP AFTER MIDNIGHT. ALL GUIDANCE
NOW KEEPS THE SHOWERS WITH THE FRONT JUST WEST OF THE AREA UNTIL
AROUND DAYBREAK. WILL BRING IN CHANCE POPS AT 10Z WED BUT ONLY FAR
WESTERN AREAS.

LAKE WIND...WILL CONTINUE LAKE WIND THROUGH TONIGHT. WINDS WILL
PROBABLY LULL THIS EVENING AFTER SUNSET BUT WILL QUICKLY PICK BACK
UP WITH THE DEVELOPING LOW-LEVEL JET AFTER MIDNIGHT.

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
A WET AND WINDY WEDNESDAY IS IN STORE WITH THE APPROACH OF A COLD
FRONT FROM THE WEST. 60 KT LOW-LEVEL JET AHEAD OF THE FRONT WILL
CREATE BREEZY CONDITIONS INLAND WHILE IMMEDIATE COASTAL LOCATIONS
WILL BE RATHER WINDY. MOST AREAS SHOULD SEE SOME RAIN ALTHOUGH THE
NAM-12 IS NOW HINTING THAT THE FRONTAL BAND MAY BEGIN TO BREAK UP
BEFORE MAKING IT FULLY THROUGH THE AREA. THE NAM IS IN THE
MINORITY WITH THIS PROG...HOWEVER. HAVE FEATURED LIKELY POPS MOST
AREAS WITH THE PRECIP MOVING OUT DURING THE AFTERNOON HOURS. SOME
DRIER AIR SHOULD BEGIN FILTERING IN FROM THE WEST LATE IN THE DAY.

LAKE WIND...WINDS WILL BE QUITE STRONG ON LAKE MOULTRIE WEDNESDAY.
EVEN WITH WATER TEMPS IN THE MID 50S...THE 60 KT 925 MB JET WILL
BE PLENTY TO BRING SOME 30 KT GUSTS TO THE LAKE.

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE FRONT WILL HAVE MOVED THROUGH THE CWA BY WEDNESDAY EVENING
WITH STRONG LOW LEVEL DRYING BRINGING AN ABRUPT END TO THE RAIN
CHANCES. TEMPERATURES WILL BE COOLING SIGNIFICANTLY BEHIND THE
FRONT WITH MORNING LOWS THURSDAY WITHIN A FEW DEGREES OF 40...
WARMER AT THE COAST AND COLDER INLAND. I HAVE GONE A BIT BELOW
GUIDANCE BASED ON STRENGTH OF LOW LEVEL PUSH OF POLAR AIR BEHIND
THE FRONT.

HIGH PRESSURE WILL BE IN CONTROL BEHIND THE FRONT WITH AFTERNOON
TEMPERATURES AROUND NORMAL THROUGH FRIDAY. WINDS WILL START A BIT
BRISK THURSDAY...BUT WILL COME DOWN QUITE A BIT BY FRIDAY AS THE
CENTER OF THE HIGH PRESSURE MOVES OVER THE AREA.

TEMPERATURES WILL WARM BACK UP BRIEFLY ON SATURDAY AHEAD OF THE NEXT
FRONT...AND THERE MAY BE A FEW SHOWERS AS WELL...BUT THE RETURN
FLOW AHEAD OF THE FRONT LOOKS WEAK...SO MOISTURE WILL BE LIMITED.
THE PREVIOUS GFS RUN STALLED THE FRONT OVER THE AREA SATURDAY
NIGHT...BUT THE CURRENT RUN KEEPS MOVING THE SYSTEM THROUGH.
LATEST ECMWF AGREES THE FRONT WILL CLEAR STEADILY THROUGH THE
AREA...SO I HAVE FOLLOWED THIS IDEA. HOWEVER...THE PATTERN THE
LAST FEW WEEKS HAS NOT ALLOWED COLD FRONTS TO PUSH THROUGH VERY
RAPIDLY FOR THE MOST PART...SO A STALLING FRONT WITH ADDITIONAL
CLOUDS AND SHOWERS ON SUNDAY CANNOT BE RULED OUT AS OF YET.

I HAVE LITTLE CONFIDENCE IN MONDAY AND TUESDAY OF NEXT WEEK AS
LOCATION OF UPPER TROF IN THE EASTERN HALF OF THE U.S. IS IN
QUESTION. I HAVE GENERALLY FOLLOWED THE PREVIOUS FORECASTERS
THINKING.

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
PERSISTENT MVFR STRATUS DECK MOVING IN FROM THE GULF WILL
CONTINUE TO AFFECT TERMINALS AT LEAST THROUGH THE EVENING. A LOW-
LEVEL JET WILL DEVELOP OVERNIGHT WHICH WILL PRODUCE LOW-LEVEL WIND
SHEAR FROM SHORTLY AFTER MIDNIGHT UNTIL A FEW HRS AFTER DAYBREAK
WED. MAIN PRECIP WITH THE COLD FRONT EXPECTED BETWEEN 14Z AND 19Z.

EXTENDED AVIATION OUTLOOK...MAIN CONCERN FOR THE SECOND HALF OF
THE WEEK WILL BE BREEZY CONDITIONS WEDNESDAY NIGHT AND THURSDAY.
NO CIGS OR VSBY RESTRICTIONS ARE EXPECTED. NEXT CHANCE OF ANY
MVFR/IFR CONDITIONS WILL BE SATURDAY WITH SHOWERS ALONG THE NEXT
COLD FRONT.

.MARINE...
WINDS WILL QUICKLY INCREASE ACROSS THE WATERS AFTER MIDNIGHT
TONIGHT AS A POTENT LOW-LEVEL JET DEVELOPS AHEAD OF AN APPROACHING
FRONT. 925 MB WINDS OF 60 KT WITH NEARLY 55 KT AT 1000 MB
GEOSTROPHIC WILL SUPPORT SOLID 30 KT SFC WINDS BY LATE TONIGHT.
WED MORNING WE WILL BE QUITE CLOSE TO GALE FORCE WINDS...ALTHOUGH
HAVE KEPT WINDS RIGHT AT 30 KT AT THIS TIME AS THE WINDOW FOR
GALES IS SMALL. A LULL IS POSSIBLE DURING THE WED AFTERNOON TIME-
FRAME AS THE FRONT SHIFTS THROUGH AND WINDS DIMINISH. HAVE SMALL
CRAFT ADVISORIES FOR ALL WATERS. SEA FOG HAS BEEN AN ISSUE TODAY.
WILL KEEP DENSE FOG ADVISORY GOING THROUGH 7 PM ALTHOUGH VIS
SATELLITE SHOWS THE BACK EDGE POTENTIALLY SCOURING.

GALES ARE STILL A POSSIBILITY ON WEDNESDAY NIGHT...BUT HAVE KEPT
SUSTAINED WINDS BELOW CRITERIA WITH A FEW GUSTS JUST TOUCHING GALE
FORCE. THIS WILL HAVE TO BE WATCHED. BEST CHANCE WOULD BE FROM 7
PM TO MIDNIGHT WHEN THE PRESSURE GRADIENT IS AT ITS TIGHTEST.
WINDS WILL STAY UP INTO THURSDAY...THEN GRADUALLY DIMINISH
THURSDAY NIGHT WITH HIGH PRESSURE MOVING OVERHEAD. WINDS AND SEAS
WILL BE QUIET ON FRIDAY...THEN PICK UP AGAIN ON SATURDAY AHEAD OF
THE NEXT COLD FRONT...ALTHOUGH GALES LOOK VERY UNLIKELY WITH THAT
EVENT.

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY UNTIL 5 PM EST THURSDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ352-354.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST THURSDAY NIGHT FOR
     AMZ350.
     SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR AMZ374.
     SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST
     THURSDAY FOR AMZ330.
     DENSE FOG ADVISORY UNTIL 7 PM TONIGHT FOR AMZ350.

JRL/ALSHEIMER