[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 020542
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN DEC 02 2007

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N10W 5N23W 4N31W 3N40W 4N52W.
SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM S OF THE AXIS
BETWEEN 15W-31W.

DISCUSSION...

GULF OF MEXICO...
FAIR AND MILD CONDITIONS EXIST ACROSS THE ENTIRE GULF THANKS IN
PART TO A SPRAWLING UPPER ANTICYCLONE CENTERED OVER THE N
CENTRAL WATERS NEAR 28N89W. ABUNDANT SUBSIDENCE IS EMBEDDED IN
THIS HIGH...ESPECIALLY S OF 26N. AT THE SFC...HIGH PRES RIDGING
EXTENDS SW FROM SOUTHEASTERN CANADA. THIS PATTERN HAS ALLOWED
WINDS TO BE FAIRLY LIGHT TO MODERATE OUT OF THE E TO SE...EXCEPT
SLY IN THE FAR WRN GULF. A FEW PATCHES OF LOW-LEVEL CLOUDINESS
...WHICH COULD CONTAIN AN ISOLATED SHOWER AS NOTED IN DOPPLER
RADAR...IS EVIDENT ON NIGHT CHANNEL SAT IMAGES E OF 90W. A
CHANGE IN AIRMASS IS EXPECTED TO BEGIN FILTERING IN ABOUT 24-36
HOURS AS A COLD FRONT PUSHES INTO THE NW WATERS. THIS FRONT IS
WILL ADVECT A COOLER AND MUCH DRIER AIRMASS INTO THE REGION.

CARIBBEAN SEA...
LIKE THE GULF OF MEXICO...THE CARIBBEAN IS ALSO VERY QUIET THIS
EARLY MORNING WITH WATER VAPOR IMAGERY REVEALING A MID-UPPER
RIDGE/TROUGH PATTERN AND A LARGE SCALE STABLE ENVIRONMENT. AT
THE SFC...THE TAIL END OF A CENTRAL ATLC TROUGH CUTS ACROSS THE
E CARIB. ENHANCED NLY FLOW TO THE W OF THE TROUGH IS PULLING IN
STREAMS OF SHALLOW SHOWERS FROM THE ATLC ACROSS PUERTO
RICO...THE DOMINICAN REPUBLIC AND ELSEWHERE N OF 15N BETWEEN 66W
AND 70W. THIS TROUGH IS PRODUCING A WEAK PRES PATTERN WHICH HAS
ALLOWED WINDS TO BE LIGHT AND VARIABLE NEAR/OVER THE LESSER
ANTILLES AS NOTED IN SFC OBS AND A RECENT QSCAT PASS. SFC WINDS
ELSEWHERE ARE MODERATE TO STRONG GENERALLY OUT OF THE NE.

ATLANTIC OCEAN...
SLOWLY WEAKENING COLD FRONT IS MOVING ACROSS THE W ATLC ANALYZED
FROM 32N62W TO 28N79W. THE WRN PART OF THE FRONT APPEARS TO BE
BREAKING OFF FROM THE MAIN BOUNDARY AND PUSHING WWD STEERED BY
THE PREVAILING LOW-LEVEL WINDS. SCATTERED SHOWERS ARE LIKELY
FROM 27N-32N BETWEEN 76W-79W AND ISOLATED SHOWERS ARE POSSIBLE
ELSEWHERE WITHIN 60 NM OF THE FRONT. IN THE CENTRAL ATLC...THE
MAIN FEATURE IS A 1011 MB LOW PRES SYSTEM CENTERED NEAR 26N54W
WITH A TRAILING TROUGH EXTENDING SW ACROSS THE LEEWARD ISLANDS.
THIS SFC LOW IS UNDERNEATH A FAIRLY DEEP MID-UPPER TROUGH.
LOW-LEVEL CONVERGENCE AND LIFT NEAR THE SFC LOW IS GENERATING
SCATTERED SHOWERS AND TSTMS FROM 23N-27N BETWEEN 53W-55W.
DIFFLUENT ALOFT ON THE E SIDE OF THE UPPER TROUGH IS PRODUCING A
LARGER AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS BETWEEN
40W-51W N OF 11N. A WEAK SFC TROUGH ALONG 56W/57W FROM 8N-16N IS
PRODUCING SLIGHT CYCLONIC TURNING IN THE WINDS BUT LITTLE OTHER
EFFECTS.

THE ERN ATLC IS DOMINATED BY SFC RIDGING EXTENDING SWD FROM A
1028 MB HIGH NEAR THE AZORES. NE TO ELY TRADES ARE STRONGEST
BETWEEN THE CANARY ISLANDS AND ABOUT 26N AS REVEALED BY A RECENT
ASCAT PASS. THE MID AND UPPER FLOW IS MAINLY W TO NW ACROSS THIS
REGION BETWEEN RIDGING EXTENDING NWD FROM THE EQUATOR...AND A
LARGE UPPER TROUGH EXTENDING SW FROM EUROPE THRU THE CANARY
ISLANDS. STRONG FLOW BETWEEN THESE SYSTEMS IS ADVECTING HIGH
LEVEL CLOUDINESS MAINLY S OF 22N. A WEAK UPPER LOW CENTERED NEAR
30N31W IS PRODUCING SIMILAR CLOUDINESS WITHIN 90 NM.

$$
CANGIALOSI


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