[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 19 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...THE ITCZ...
ITCZ AXIS IS ALONG 7N10W 5N26W 4N45W 3N52W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM THE
EQUATOR TO THE COAST OF AFRICA E OF 8W ACROSS THE PRIME
MERIDIAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM
1N-10N BETWEEN 35N-50W.

...DISCUSSION...
GULF OF MEXICO...
MID/UPPER LEVEL SHORTWAVE TROUGH IS OVER THE CENTRAL GULF FROM
THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA. THIS UPPER
TROUGH IS EMBEDDED WITHIN A BROAD UPPER RIDGE THAT COVERS THE E
US AND GULF OF MEXICO INTO THE W ATLC. A 1018 MB LOW IS
DEVELOPING IN THE W GULF NEAR 26N94W ALONG THE SURFACE TROUGH
THAT EXTENDS ALONG 94W FROM 24N-29N. SCATTERED SHOWERS ARE N OF
25N FROM 90W-97W. AN UPPER TROUGH FROM OVER THE W ATLC EXTENDS
ACROSS THE FLORIDA PENINSULA INTO THE SE GULF E OF 82W. THE NEXT
COLD FRONT IS EXPECTED TO MOVE OFF THE TEXAS COAST ON WED
NIGHT/THU BRINGING SOME SHOWER ACTIVITY TO THE NW CORNER OF THE
GULF THEN MOVING EASTWARD. A THIN LINE OF ISOLATED SHOWERS ARE
OVER THE SE GULF ALONG 23N87W THROUGH THE STRAITS OF FLORIDA
INCLUDING THE FLORIDA KEYS TO 25N80W.

CARIBBEAN SEA...
UPPER TROUGH FROM THE W ATLC DIPS S INTO THE W CARIBBEAN TO 16N
FROM 68W-82W BRINGING VERY DRY UPPER AIR AND STRONG SUBSIDENCE
ACROSS CUBA...JAMAICA...AND THE CAYMAN ISLANDS WITH MODERATE
SUBSIDENCE ALREADY IN PLACE OVER THE REMAINDER OF THE W
CARIBBEAN. THIS IS GIVING THE AREA SHOWER FREE CONDITIONS. BROAD
UPPER RIDGE COVERS THE REMAINDER OF THE CARIBBEAN E OF 68W
ADVECTING TROPICAL ACROSS THE AREA COUPLED WITH THE DIFFLUENCE
OVER THE SAME AREA ARE GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 14N-19N BETWEEN 66W-73W. MODERATE TRADE WINDS
DOMINATE THE ENTIRE CARIBBEAN.

ATLANTIC OCEAN...
BROAD UPPER RIDGE EXTENDS FROM THE E US OVER THE NW ATLC W OF
50W WITH AN UPPER LEVEL LOW OVER THE S BAHAMA ISLANDS NEAR
22N72W COVERING THE SW ATLC S OF 27N FROM 65W-82W DIPPING INTO
THE W CARIBBEAN. A SURFACE REFLECTION IN THE FORM OF A SURFACE
TROUGH EXTENDS FROM 24N66W INTO THE CARIBBEAN ACROSS HAITI TO
15N76W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM
20N-24N BETWEEN 62W-72W. BROAD SURFACE RIDGE COVERS THE
REMAINDER OF THE W ATLC WITH A 1025 AND 1024 MB HIGHS LOCATED
NEAR 32N73W AND 30N58W RESPECTIVELY. DEEP LAYERED TROUGH IS OVER
THE E/CENTRAL ATLC EXTENDING FROM AN UPPER LOW NEAR 29N34W SW TO
NEAR 19N42W. THE ASSOCIATED COLD FRONT ENTERS THE REGION NEAR
32N36W TO NEAR 29N37W WHERE IT DISSIPATES TO 22N47W. A
PRE-FRONTAL TROUGH EXTENDS FROM 31N33W ALONG 24N37W TO 19N43W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH THE
UPPER LOW N OF 27N FROM 30W-37W. AN UPPER RIDGE IS OVER THE E
ATLC FROM 6N17W ALONG 22N21W TO BEYOND 32N22W WITH ENOUGH
DIFFLUENCE TO THE W TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS
WELL E OF THE COLD FRONT WITHIN 120/150 NM OF LINE FROM 22N30W
TO 28N27W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N
FROM 22W-30W.

$$
WALLACE




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