[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021151
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED JAN 02 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 UTC

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N10W 5N20W 2N30W CROSSING THE
EQUATOR NEAR 41W. SCATTERED MODERATE CONVECTION IS WITHIN 210 NM
N OF THE AXIS BETWEEN 23W-30W AND WITHIN 150 NM S OF THE AXIS
BETWEEN 10W-12W.

...DISCUSSION...
GULF OF MEXICO...
A COLD AIRMASS HAS BUILT INTO THE ENTIRE AREA BEHIND A STRONG
COLD FRONT EXTENDING FROM THE W ATLC WATERS INTO THE EXTREME NW
CARIBBEAN. VERY TIGHT PRESSURE GRADIENT BETWEEN THE FRONT AND A
1053 MB HIGH OVER THE ROCKIES IS PRODUCING NLY GALE FORCE WINDS
ACROSS MUCH OF THE SRN HALF OF THE REGION AS NOTED IN BUOY/SHIP
DATA AND RECENT SCATTEROMETER PASSES. THIS STRONG FLOW AND NLY
FETCH/SWELL IS CREATING DANGEROUS MARINE CONDITIONS WITH SEAS
BUILDING UPWARD OF 20 FT...HIGHEST IN THE SW PORTION. WINDS AND
SEAS WILL BEGIN TO SUBSIDE FROM W TO E ON THU AS THE STRONG HIGH
WEAKENS AND SHIFTS E. LOW TEMPERATURES ARE EXPECTED TO BE THE
COLDEST OF THE SEASON FOR MUCH OF FLORIDA ON THU WITH GFS
PROJECTING MINIMUMS IN THE LOW TEENS ACROSS THE FL PANHANDLE AND
EVEN MID TO UPPER 30'S RIGHT HERE IN THE MIAMI AREA. MULTILAYER
CLOUDINESS AND EMBEDDED SHOWERS COVER THE AREA S OF 25N W OF 90W
ASSOCIATED WITH LOW-LEVEL CONVERGING FLOW OVER MEXICO AND A
DIFFLUENT UPPER PATTERN ABOVE THE BAY OF CAMPECHE.

CARIBBEAN SEA...
TYPICAL TRANQUIL CONDITIONS PREVAIL ACROSS MOST OF THE CARIB
THIS MORNING UNDER A VERY SUBSIDENT UPPER RIDGE CENTERED JUST S
OF HISPANIOLA NEAR 17N70W. THIS WIDESPREAD SINKING AIRMASS IS
SUPPRESSING THE DEVELOPMENT OF CONVECTION AND KEEPING STREAMS OF
MOISTURE CARRIED BY THE TRADES SHALLOW. HOWEVER...THERE IS AN
EXCEPTION TO THE TRANQUILITY IN THE FAR NW CORNER WHERE A COLD
FRONT EXTENDS FROM W CUBA TO THE YUCATAN PENINSULA ALONG 23N81W
20N88W. NLY WINDS ARE SHARPLY INCREASING BEHIND THIS BOUNDARY
AND ARE EXPECTED TO REACH GALE FORCE VERY SHORTLY. SCATTERED
SHOWERS ARE POSSIBLE WITHIN 120 NM NW OF THE FRONT. WINDS ARE
EXPECTED TO DECREASE BELOW GALE FORCE IN ABOUT 24 HOURS BUT
SHOULD REMAIN STRONG THRU THE END OF THE WEEK.

ATLANTIC OCEAN...
THE LOW PRESSURE SYSTEM THAT THREATENED TO BECOME A NAMED
SUBTROPICAL STORM DAYS AGO CONTINUES TO WEAKEN AS IT MOVES W
STEERED BY A LOW-MID LEVEL RIDGE. SAT IMAGES SHOW A HIGHLY
ELONGATED N-S SFC TROUGH AXIS ALONG 47W WITH A POSSIBLE LOW PRES
MINIMUM AND ELONGATED CIRCULATION ALONG THE TROUGH NEAR
22N...BUT EVEN THIS APPEARS TO BE OPENING. GALES HAVE COME TO AN
END BUT WINDS REMAIN STRONG NEAR THE TROUGH AXIS. THE SMALL
PATCH OF CONVECTION DISCUSSED EARLIER HAS DIMINISHED LEAVING A
COMPLETELY SHALLOW SYSTEM.

ANOTHER SIGNIFICANT FEATURE IS A STRONG COLD FRONT IN THE W ATLC
FROM 32N70W THROUGH THE NW BAHAMAS TO W CUBA. SCATTERED SHOWERS
ARE POSSIBLE WITHIN 90 NM OF THE FRONT. NW WINDS INCREASE
SIGNIFICANTLY BEHIND THE BOUNDARY BUT EXPECTED TO BE JUST BELOW
GALE FORCE. MUCH COLDER AIR IS USHERING IN BEHIND THE
FRONT...SEE GULF OF MEXICO SECTION FOR MORE DETAILS ON THE
EXTENT OF THIS COLD AIRMASS. THIS FRONTAL ZONE AND ITS UPPER
TROUGH WILL ABSORB THE AFOREMENTIONED LOW PRES SYSTEM IN THE
CENTRAL ATLC WITHIN THE NEXT COUPLE OF DAYS. THE ONLY OTHER
NOTABLE FEATURE IS A SW TO WLY UPPER JET ORIGINATING JUST E OF
AN UPPER TROUGH BASE NEAR 13N46W AND EXTENDING NE ALONG 21N32W
26N15W. ABUNDANT MID-HIGH LEVEL CLOUDINESS AND EMBEDDED
SCATTERED SHOWERS ARE WITHIN 660 NM S/SE OF THE JET AXIS
SUPPORTED BY UPPER DIFFLUENCE AND INSTABILITY.

$$
CANGIALOSI


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