[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200532
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE DEC 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 3N28W 2N41W EQ50W. SCATTERED
MODERATE/STRONG CONVECTION IS WITHIN 75 NM OF THE AXIS FROM
15W-18W...WITHIN 90 NM OF THE AXIS FROM 23W-27W...AND WITHIN 120
NM OF THE AXIS FROM 33W-43W. SCATTERED CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION DOT THE REMAINDER OF THE
AREA FROM 3N-8N BETWEEN 8W-36W.

...DISCUSSION...

GULF OF MEXICO AND W ATLANTIC...
BROAD DEEP LAYERED TROUGH COVERS THE E HALF OF THE U.S. INTO THE
W ATLC N OF 32N. ASSOCIATED COLD FRONT EXTENDS INTO THE W ATLC
THROUGH 32N62W SW TO THE N BAHAMA ISLANDS TO A 1018 MB LOW NEAR
27N77W ACROSS W CUBA NEAR 23N81W TO THE YUCATAN PENINSULA NEAR
20N90W. A DISSIPATING STATIONARY FRONT REMAINS NW OVER CENTRAL
MEXICO. SCATTERED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS
ARE ACROSS THE GULF S OF 27N INCLUDING THE FLORIDA PENINSULA AND
W ATLC N OF 25N W OF 70W. BROAD UPPER RIDGE COVERS THE GULF AND
W ATLC WITH SW TO W FLOW ACROSS THE AREA. A SUBTROPICAL JET WITH
WINDS OF 90 TO 110 KT CUTS ACROSS THE GULF WITHIN 150 NM OF LINE
19N96W OVER FLORIDA NEAR 28N81W TO 30N72W. THIS IS ADVECTING
PACIFIC MOISTURE ACROSS MEXICO TO OVER THE GULF AND W ATLC.
SURFACE HIGH PRESSURE CONTINUES TO BUILD S FROM OVER THE U.S.
PUSHING THE FRONT INTO THE NW CARIBBEAN. THE LOW AND FRONT WILL
BECOME NEARLY STATIONARY FOR THE NEXT 36 TO 48 HRS BEFORE
GRADUALLY MOVING NE BECOMING ENTRAINED IN A LARGER LOW SYSTEM BY
THE END OF THE WEEK. THIS WILL CAUSE A GRADUALLY CLEARING OF THE
GULF WITH WET WEATHER REMAINING ACROSS PORTIONS OF THE W ATLC.

CARIBBEAN...
BROAD UPPER RIDGE COVERS THE CARIBBEAN EXCEPT IN THE SE WHERE AN
UPPER TROUGH EXTENDING FROM THE NE ATLC THROUGH THE CENTRAL ATLC
IS S OF 15N E OF 67W. STRONG SUBSIDENCE AND DRY UPPER AIR
DOMINATE ALL BUT THE YUCATAN CHANNEL N OF THE COLD FRONT THAT
CROSS W CUBA NEAR 23N81W TO THE YUCATAN PENINSULA NEAR 20N90W...
WITH BROKEN/OVERCAST LOW/MID CLOUDS WITH ISOLATED SHOWERS.
MODERATE SURFACE EASTERLY TRADEWINDS COVER THE ENTIRE CARIBBEAN
RELAXING SOMEWHAT FROM THE PAST FEW DAYS. MOISTURE WILL REMAIN
LIMITED ACROSS THE CARIBBEAN UNTIL MID WEEK WHEN AN INCREASE
OVER THE W CARIBBEAN COULD TRIGGER SHOWERS/ISOLATED
THUNDERSTORMS.

REMAINDER OF ATLANTIC...
BROAD UPPER RIDGE THAT COVERS THE GULF AND CARIBBEAN EXTENDS
ACROSS INTO THE CENTRAL ATLC NEAR 55W GIVING THE AREA S OF 25N W
OF 53W MODERATE/STRONG SUBSIDENCE AND DRY UPPER AIR. AT THE
SURFACE...A POCKET OF HIGH PRESSURE COVERS THE AREA N OF 17N
BETWEEN 34W AND THE FRONTAL BOUNDARY IN THE W ATLC WITH A 1021
MB HIGH ANCHORED NEAR 29N46W. A DEEP LAYERED TROUGH EXTENDS
THROUGH NEAR 32N21W IN THE NE ATLC TO AN UPPER MID/LOW NEAR
29N26W SW ALONG 21N37W TO THE COAST OF SOUTH AMERICA NEAR 11N65W
INCLUDING THE SE CARIBBEAN. MODERATE/STRONG SUBSIDENCE IS WITHIN
200/250 NM OF LINE FROM 26N31W TO 18N40W AND FROM 7N-21N BETWEEN
40W-53W...THE DRIEST AIR IS FROM 9N-16N BETWEEN 43W-63W.
ASSOCIATED FRONTAL SYSTEM IS N OF THE REGION. AN UPPER RIDGE
OVER THE FAR E ATLC EXTENDS N FROM AN UPPER HIGH NEAR 7N16W TO
34N10W. A STRONG JET STREAM WITH WINDS OF 100 TO 150 KT IS ALONG
THE N PERIPHERY OF THE RIDGE EXTENDING ALONG 12N40W TO A PEAK
NEAR 32N10W. STRONG DIFFLUENCE...AIDED BY THE JET...IS PRODUCING
A LARGE AREA OF DENSE HIGH CLOUDS WITH SCATTERED SHOWERS OVER
THE AREA NW WITHIN 350/425 NM OF LINE FROM THE TROPICS NEAR
10N35W 20N25W OVER AFRICA NEAR 27N13W INCLUDING THE CAPE VERDE
AND CANARY ISLANDS.

$$
WALLACE


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