[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181810
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN DEC 18 2005

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ 5N10W 3N20W 3N30W 4N40W 4N47W...3N49W 2N54W. SCATTERED TO
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 7N TO 9N BETWEEN
38W AND 40W. A FEW STRONG CELLS OF SHOWERS AND THUNDERSTORMS
ALSO ARE FOUND FROM 5N TO 6N BETWEEN 26W AND 28W...AND FROM 5N
TO 6N BETWEEN 30W AND 32W. ISOLATED MODERATE SHOWERS TO LOCALLY
STRONG THUNDERSTORMS ARE FOUND FROM 5N TO 6N BETWEEN 42W AND
44W.

...DISCUSSION...

THE GULF OF MEXICO...
THE UPPER LEVEL FLOW IN WATER VAPOR IMAGERY IS FROM THE WEST AND
SOUTHWEST...ACROSS INTERIOR MEXICO...INTO THE GULF WATERS. THE
18/1500 UTC CIMSS SATELLITE DERIVED WIND DATA SHOW MIDDLE TO
UPPER LEVEL WEST TO SOUTHWESTERLY WIND FLOW IN THE GULF WATERS.
BROKEN TO OVERCAST HIGH CLOUDS COVER INTERIOR MEXICO BETWEEN 95W
AND 110W...AND MOVING INTO TEXAS EAST OF 100W. MIDDLE TO UPPER
LEVEL DRY AIR IS WEST OF THE SHOWERS AND THUNDERSTORMS WHICH ARE
FIRING UP ALONG A SURFACE FRONTAL BOUNDARY. THE FRONT IS
STATIONARY FROM THE EAST CENTRAL GULF WATERS NEAR 26N83W TO
A 1018 MB LOW CENTER NEAR 26N87W. A COLD FRONT RUNS FROM 26N87W
TO A 1016 MB NORTHWESTERN YUCATAN PENINSULA LOW CENTER...
CONTINUING TO MEXICO JUST EAST OF THE ISTHMUS OF TEHUANTEPEC.
SCATTERED TO NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FOUND
FROM 22N TO 24N BETWEEN 86W AND 88W. OTHER CLOUDS AND POSSIBLE
PRECIPITATION IS SOUTHEAST OF 27N83W 23N90W...WITH SOME AREAS
POSSIBLY DISSIPATING AND RE-GENERATING NEARBY.

THE CARIBBEAN SEA...
A STRONG UPPER LEVEL ANTICYCLONE REMAINS CENTERED IN THE
SOUTHWESTERN CORNER OF THE AREA NEAR 13N78W. A RIDGE EXTENDS
NORTHEASTWARD THROUGH THE WINDWARD PASSAGE INTO THE WESTERN
ATLANTIC OCEAN. MIDDLE TO UPPER LEVEL DRY AIR IS EVERYWHERE
WITH POSSIBLY THE COMPARATIVELY DRYEST AIR FROM VENEZUELA TO THE
ATLANTIC OCEAN AND IN THE SOUTHEASTERN CORNER OF THE AREA FROM
8N TO 13N BETWEEN 54W AND 70W. ISOLATED MODERATE SHOWERS ARE
POSSIBLE IN THE TRADEWIND SCATTERED TO BROKEN LOW AND MIDDLE
LEVEL CLOUDS...MAINLY FROM 12N TO 20N BETWEEN 60W AND 83W.

THE ATLANTIC OCEAN...
UPPER LEVEL ANTICYCLONIC FLOW COVERS THE ATLANTIC WATERS NORTH
OF 20N WEST OF 55W. A NORTHEAST-TO-SOUTHWEST ORIENTED UPPER
LEVEL RIDGE PASSES THROUGH 32N58W TO 24N65W TO THE WINDWARD
PASSAGE. A COLD FRONT GOES FROM A 1018 MB LOW PRESSURE CENTER
NEAR 32N75W TO THE EASTERN FLORIDA COAST NEAR 28N AND THEN INTO
THE EAST CENTRAL GULF WATERS. SCATTERED MODERATE SHOWERS AND
ISOLATED STRONG THUNDERSTORMS ARE FOUND FROM 28N TO 31N BETWEEN
75W AND 78W. A SURFACE RIDGE/BROAD HIGH PRESSURE IS IN BETWEEN
THE WESTERN ATLANTIC COLD FRONT AND THE PERSISTENT EASTERN
ATLANTIC FRONTAL BOUNDARY. THE RIDGE EXACTLY RUNS FROM
A 1026 MB HIGH CENTER NEAR 32N57W TO 27N69W ACROSS CUBA TO
21N83W IN THE NORTHWESTERN CARIBBEAN SEA. BROAD HIGH PRESSURE
IS NORTH OF 20N BETWEEN 50W AND THE WESTERN ATLANTIC FRONT.
A SURFACE TROUGH CONTINUES IN THE ATLANTIC WATERS...ALONG
47W/48W SOUTH OF 12N MOVING WEST 10 TO 15 KT. ISOLATED MODERATE
SHOWERS AND POSSIBLE THUNDERSTORMS ARE FOUND IN THE ITCZ...
POSSIBLY JUST WITH THIS TROUGH...FROM 6N TO 10N BETWEEN 49W
AND 51W. A MIDDLE TO UPPER LEVEL TROUGH CONTINUES FROM A BROAD
AREA OF CYCLONIC FLOW...WITH AT LEAST MORE THAN ONE SWIRL OR
CENTER...NEAR 31N30W...TO 23N40W 16N50W 9N60W. UPPER LEVEL
ANTICYCLONIC FLOW IS SOUTH AND SOUTHEAST OF THIS WHOLE TROUGH.
THE BROAD MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION IS
SUPPORTING TWO 1008 MB SURFACE LOW PRESSURE CENTERS. ONE OF
THOSE CENTERS IS NEAR 30N30W AND THE OTHER ONE IS NEAR 28N33W.
A TROUGH CONNECTS THE 30N30W CENTER TO THE 28N33W CENTER...AND
TO 24N36W 22N41W. A WARM FRONT STRETCHES FROM THE 30N30W LOW
CENTER TO 31N24W. SCATTERED MODERATE TO ISOLATED STRONG SHOWERS
AND THUNDERSTORMS ARE FOUND WITHIN A 30 NM RADIUS OF 32N23W AND
FROM 32N TO 33N BETWEEN 26W AND 28W. OTHER ISOLATED MODERATE
SHOWERS COVER THE WATERS NORTH OF 29N BETWEEN 18W AND 34W. THE
LOW AND TROUGH ARE EXPECTED TO CONSOLIDATE DURING THE NEXT FEW
DAYS AND LIFT NORTHEASTWARD TOWARD THE MADEIRA ISLANDS...THEN
DROP SOUTHWARD TOWARD THE CANARY ISLANDS BY WEDNESDAY.

$$
MT


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