[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 182344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU 18 NOV 2004

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 10N10W 3N33W 6N47W 4N53W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF LINE
5N25W-3N30W. ISOLATED CLUSTERS OF SCATTERED MODERATE CONVECTION
ARE FROM 2N-10N BETWEEN 37W-52W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LOW IS MOVING NE OVER THE UPPER MISSISSIPPI VALLEY
WITH THE TROUGH AXIS EXTENDING TO OVER THE SE UNITED STATES. THE
ASSOCIATED COLD FRONT IS WELL BEHIND THE UPPER TROUGH AXIS
ENTERING THE GULF ALONG THE LOUISIANA/TEXAS BORDER TO 26N96W
WHERE IT CONTINUES W INLAND OVER NE MEXICO AS A STATIONARY
FRONT. THIS IS GENERATING WIDESPREAD CLOUDINESS WITH SCATTERED
SHOWERS OVER THE N GULF N OF 25N W OF 84W TO THE COLD FRONT. THE
UPPER LEVEL ENERGY IS WELL N OF THE GULF RESULTING IN A SLOW
MOVING FRONT WITH DIMINISHED THUNDERSTORM ACTIVITY. AN MID/UPPER
LEVEL RIDGE IS STARTING TO MOVE OVER W MEXICO AND THE UPPER
TROUGH OVER THE MISSISSIPPI VALLEY IS RESULTING IN NW FLOW
ACROSS ALL OF THE GULF. STRONG SUBSIDENCE AND DRY AIR AT ALL
LEVELS IS LEAVING THE GULF SHOWER FREE S OF 25N.

CARIBBEAN SEA...
SW FLOW DOMINATES MOST OF THE CARIBBEAN EXCEPT IN THE SE WHERE A
A WEAK MID LEVEL LOW IS CENTERED JUST E OF THE ABC ISLANDS NEAR
12N67W WITH AN EAST/WEST TROUGH EXTENDING FROM OVER THE ABC
ISLANDS TO THE WINDWARD ISLANDS. AT THE SURFACE...A TROUGH
EXTENDS FROM 16N55W THROUGH THE WINDWARDS TO S OF THE ABC
ISLANDS TO 11N70W. THE SW FLOW OVER THE REMAINDER OF THE
CARIBBEAN IS THE RESULT OF A VERY LARGE MID/UPPER LEVEL HIGH
OVER THE TROPICAL ATLC WITH A RIDGE AXIS EXTENDING SW ACROSS
SOUTH AMERICA JUST N OF THE EQUATOR. THE STRONG SUBSIDENCE FROM
THE GULF AND THE W ATLC REMAINS OVER THE NW CARIBBEAN N OF 14N W
OF 75W WITH ONLY BROKEN LOW LEVEL CLOUDS AND ISOLATED SHOWERS.
TROPICAL MOISTURE BEING ADVECTED N AND NE COVERS THE E AND SW
CARIBBEAN GENERATING WIDESPREAD CLOUDINESS WITH SCATTERED
SHOWERS/THUNDERSTORMS WITHIN 150 NM OF LINE FROM ACROSS THE
LEEWARD ISLANDS NEAR 16N62W TO OVER SOUTH AMERICA NEAR 11N70W
AND S OF 12N E OF 82W TO OVER COLOMBIA AND PANAMA.

ATLANTIC...
DEEP LAYERED...BROAD TROUGH CONTROLS THE ATLC W OF 50W WITH ONE
MID/UPPER TROUGH MOVING NE OUT OF THE AREA ALONG 52W FROM
43W-60W AND A MID/UPPER LOW MOVING SE IN TO THE AREA NEAR 32N73W
WITH A TROUGH EXTENDING S OVER THE BAHAMAS TO 23N76W. THE
INITIAL COLD FRONT IS NOW DISSIPATING ALONG 32N37W 22N50W INTO
THE NE CARIBBEAN OVER THE LEEWARD ISLANDS TO 16N66W. A
REINFORCING COLD FRONT IS ENTERING THE AREA THROUGH 32N50W
EXTENDING S TO 27N55W THEN NW TO 31N69W. STRONG SUBSIDENCE AND
DRY AIR AT THE UPPER LEVELS COVERS THE AREA FROM OVER HISPANIOLA
AND CUBA TO 31N BETWEEN 70W-80W...AND N OF A LINE FROM
19N70W-24N53W-30N36W. INCREASING STRATOCUMULUS CLOUDS ARE NOTED
BEHIND THE SECOND FRONT. A SURFACE TROUGH...REMNANTS OF AN OLD
FRONTAL BOUNDARY EXTENDS FROM 30N35W ALONG 24N37W TO 20N42W
GENERATING WIDESPREAD CLOUDINESS WITH SCATTERED SHOWERS N OF 20N
FROM 32W-38W WITH THUNDERSTORMS DEVELOPING N OF THE REGION.
STRONG MID/UPPER HIGH IS OVER THE TROPICAL ATLC NEAR 12N50W AND
CONTROLS MOST OF THE DEEP TROPICAL ATLC AND LIMITING CONVECTION
WITHIN THE ITCZ W OF 35W. THE MID/UPPER LEVEL RIDGE AXIS EXTENDS
FROM OVER SOUTH AMERICA THROUGH THE HIGH THEN NE ALONG 23N40W TO
BEYOND 32N30W. A SUBTROPICAL JET WITH WINDS OF 100 TO 130 KT IS
THE BOUNDARY BETWEEN THE UPPER TROUGH OVER THE W ATLC AND THE
UPPER HIGH OVER THE TROPICS. OVER THE FAR E ATLC...A MID/UPPER
LEVEL TROUGH EXTENDS FROM A LOW OVER MADEIRA ISLANDS S ALONG
23N21W TO THE CAPE VERDE ISLANDS NEAR 15N23W. THIS UPPER TROUGH
IS ADVECTING STRONG SUBSIDENCE AND DRY UPPER AIR S COVERING THE
E ATLC N OF 20N FROM 20W-27W. AT THE SURFACE...A SURFACE TROUGH
EXTENDS FROM NE OF THE CAPE VERDE ISLANDS NEAR 17N20W N TO
26N22W. NO SHOWER ACTIVITY IS NOTED.

$$
WALLACE


WWWW
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