[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081729
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE JAN 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N11W 3N20W 2N40W EQUATOR 50W.
SCATTERED MODERATE CONVECTION IS FROM 2N-6N BETWEEN 24W-34W.
SIMILAR CONVECTION IS WITHIN 90 NM S OF THE AXIS BETWEEN
12W-22W...WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 38W-40W
AND FROM THE EQUATOR TO 4N E OF 7W.

...DISCUSSION...

GULF OF MEXICO...
THIS REGION LIES ON THE SW PERIPHERY OF A STRONG BERMUDA-AZORES
RIDGE ALLOWING THE LOW-LEVEL FLOW TO BE SE TO S ACROSS THE
AREA...STRONGEST IN THE MIDDLE AND W GULF WHERE THE PRES
GRADIENT IS TIGHTENED DUE TO AN APPROACHING FRONT. IN THE MID
AND UPPER LEVELS...THE FLOW IS MAINLY W TO SW ON THE W SIDE OF A
RIDGE AXIS OVER THE BAHAMAS. THIS FLOW IS TRANSPORTING VERY
LITTLE MOISTURE AS MODERATE SUBSIDENCE HOLDS. THE AFOREMENTIONED
FRONT IS EXPECTED TO MOVE INTO THE NW WATERS LATER TODAY BUT NOT
ANTICIPATED TO MAKE IT MUCH FARTHER THAN THAT AS ITS UPPER
SUPPORT PULLS TOWARD THE NE.

CARIBBEAN SEA...
TYPICAL TRANQUIL WEATHER PREVAILS ACROSS THE CARIBBEAN WITH
MAINLY MODERATE TRADE WIND FLOW...EXCEPT STRONG NEAR THE COAST
OF COLOMBIA. LOW-LEVEL PATCHES OF MOISTURE ARE BEING PICKED UP
AND STEERED WWD BY THE TRADES BUT ARE NOT ACQUIRING MUCH
VERTICAL DEPTH DUE TO FAIRLY DRY AIR ALOFT ON THE N SIDE OF A
BROAD ELONGATED RIDGE OVER SOUTH AMERICA. THE MOST STABLE AIR IS
N OF 17N WHERE THE FLOW ALOFT IS CONFLUENT. TRADE WINDS ARE
EXPECTED TO DECREASE OVER THE NEXT DAY OR TWO AS THE SFC
TROUGH...CURRENTLY NE OF THE AREA...SHIFTS W.

ATLANTIC OCEAN...
VERY BROAD TROUGHING DOMINATES THE CENTRAL ATLC WITH A PAIR OF
EMBEDDED SHORTWAVES...WHICH HAVE A CONNECTION TO THE SFC. ONE OF
THESE SHORTWAVES APPEARS TO BE CUTTING OFF CENTERED NEAR 27N59W.
SCATTERED SHOWERS AND TSTMS ARE MOSTLY TO THE N AND E OF THE LOW
FROM 25N-30N BETWEEN 54W-60W. THE OTHER SHORTWAVE IS ABOUT 700
NM TO THE E ALSO TRIGGERING SCATTERED SHOWERS AND TSTMS FROM
25N-31N BETWEEN 40W-47W. AN ASSOCIATED SFC TROUGH IS ANALYZED
FROM 29N43W TO 21N50W INCREASING NE WINDS BETWEEN IT AND STRONG
HIGH PRES TO THE N. ANOTHER SFC TROUGH...FAIRLY ELONGATED IN
NATURE...LIES TO THE N OF THE GREATER ANTILLES FROM 19N63W TO
23N69W. THIS FEATURE IS ONLY GENERATING A FEW SHOWERS/TSTMS FROM
21N-22N BETWEEN 61W-62W...AS IT LIES BENEATH A SUBSIDENT
ENVIRONMENT.

THE WRN AND ERN ATLC ARE UNDER FAIRLY ZONAL FLOW OR SLIGHT
RIDGING CAUSING WIDESPREAD FAIR WEATHER. STRONG BERMUDA-AZORES
SFC RIDGE IS PRODUCING STRONG TRADES NEAR THE AFOREMENTIONED SFC
TROUGHS...OTHERWISE MODERATE ELSEWHERE.

$$
JC/CW


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