[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON DEC 21 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 4N30W 3N52W. SCATTERED
MODERATE CONVECTION IS FROM 3N-6N BETWEEN 25W-33W. SIMILAR
CONVECTION IS FROM 1N-5N BETWEEN 44W-52W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE CONTINUES ITS CONTROL OVER THE GULF OF MEXICO
ANCHORED BY A TRIO OF HIGH CENTERS STRETCHING FROM A 1027 MB
HIGH OVER SOUTHERN ALABAMA TO A 1026 MB HIGH CENTERED OVER THE
NW GULF WATERS NEAR 29N93W THEN TO A 1026 MB HIGH OVER THE EAST
CENTRAL MEXICO COAST NEAR TAMPICO. MAINLY LIGHT NE TO E WINDS
ARE OBSERVED ACROSS THE BASIN. ALOFT...MOIST SWLY FLOW COVERS A
MAJORITY OF THE GULF EAST OF AN UPPER LEVEL TROUGH AXIS
EXTENDING FROM SOUTHERN LOUISIANA CLIPPING THE NW GULF WATERS TO
SOUTHERN MEXICO NEAR THE ISTHMUS OF TEHUANTEPEC. ABUNDANT MIDDLE
TO UPPER LEVEL TROPICAL MOISTURE IS ADVECTING NE ACROSS THE
YUCATAN PENINSULA...EASTERN GULF...AND FLORIDA PENINSULA. THE
UPPER LEVEL TROUGH AND DIFFLUENT ENVIRONMENT EAST OF THE AXIS IS
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 23N W OF
90W ALONG WITH POSSIBLE ISOLATED SHOWERS ACROSS THE YUCATAN
PENINSULA AND YUCATAN CHANNEL AS THE UPPER LEVEL TROUGH SLOWLY
MOVES EASTWARD. AS THE SURFACE RIDGE MOVES EASTWARD ACROSS THE
NE GULF COAST...SE TO S RETURN FLOW IS FORECAST TO BEGIN LATE
MONDAY WITH THE NEXT COLD FRONT EXPECTED TO ENTER THE NW GULF
WATERS EARLY THURSDAY.

CARIBBEAN SEA...
A STATIONARY FRONT EXTENDS ACROSS THE WESTERN CARIBBEAN FROM
HISPANIOLA TO SOUTHERN JAMAICA ALONG 16N80W TO 9N83W. A SURFACE
TROUGH IS EAST OF THE FRONT EXTENDING FROM 18N73W TO 14N76W TO
10N76W. N-NE WINDS UP TO 30 KTS WERE CAPTURED ON AN EARLIER
WINDSAT SCATTEROMETER PASS AT 21/1122 UTC NORTH OF THE FRONT TO
20N BETWEEN 79W-84W. THE FRONT LIES BENEATH MOIST SWLY FLOW
ALOFT ON THE WESTERN SIDE OF A LARGE AND BROAD UPPER LEVEL
ANTICYCLONIC CIRCULATION CENTERED EAST OF THE LESSER ANTILLES
NEAR 16N59W. THE RIDGE IS DRAWING TROPICAL MOISTURE ACROSS
CENTRAL AMERICA AND THE CARIBBEAN W OF 75W. THIS ALONG WITH
SURFACE CONVERGENCE NEAR THE FRONT AND SURFACE TROUGH IS
SUPPORTING SCATTERED SHOWERS W OF 78W S OF THE STATIONARY FRONT
AND ELSEWHERE ACROSS THE REMAINDER OF THE NW CARIBBEAN NW OF THE
FRONT...AS WELL AS OVER PORTIONS OF NORTHERN HISPANIOLA. DRY AIR
AND SUBSIDENCE COVER THE FAR EASTERN CARIBBEAN E OF 68W AS NOTED
IN WATER VAPOR IMAGERY RESULTING IN A STABLE ENVIRONMENT AND
CLEAR SKIES THIS AFTERNOON.

ATLANTIC OCEAN...
AN OCCLUDED 970 MB LOW IS LOCATED SE OF NOVA SCOTIA CANADA NEAR
42N58W WITH A COLD FRONT ENTERING THE DISCUSSION AREA NEAR
32N45W CONTINUING SW ALONG 26N55W TO 22N64W AND BECOMES
STATIONARY TO HISPANIOLA AND INTO THE WESTERN CARIBBEAN.
ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE
FRONT...AND FARTHER E N OF 25N BETWEEN 37W-49W. A SECONDARY COLD
FRONT FOLLOWS TO THE NW ALONG 31N57W TO 27N71W...WITH STRATO-
CUMULUS CLOUDS AND STRONG W-NW WINDS OCCURRING BEHIND THE FRONT.
FARTHER EAST...A COLD FRONT ENTERS THE FAR NE CORNER OF THE
DISCUSSION AREA NEAR 32N11W AND EXTENDS S-SW THROUGH THE CANARY
ISLANDS TO 21N25W. SCATTERED SHOWERS ARE N OF 20N E OF 22W. THE
FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH AXIS THAT
EXTENDS FROM 32N22W TO THE CAPE VERDE ISLANDS TO 6N37W IN THE
TROPICAL ATLC. ELSEWHERE A SURFACE RIDGE AXIS EXTENDS E-W ALONG
17N/18N BETWEEN THE W AFRICA COAST THROUGH A 1017 MB HIGH
CENTERED NEAR 18N44W TO OVER THE EASTERN CARIBBEAN SEA NEAR
PUERTO RICO.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE.

$$
HUFFMAN





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