[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON DEC 20 2010

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 7N13W 5N20W 5N30W 3N40W 1N50W.
SCATTERED MODERATE CONVECTION IS FROM 1N-4N BETWEEN 12W AND 17W.
CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE FROM
3N-10N BETWEEN 20W AND 33W. SCATTERED MODERATE CONVECTION IS
ALSO FROM THE EQUATOR TO THE ITCZ AXIS BETWEEN 37W AND 39W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE IS MOVING INTO THE WESTERN GULF FROM
MEXICO. STRONG SUBSIDENCE AND DRY AIR DOMINATES THE AREA
LIMITING ALL BUT A FEW PASSING WIDELY SCATTERED LOW-LEVEL
CLOUDS. POSSIBLE ISOLATED SHOWERS DOT THE NW GULF N OF 24N W OF
91W. A WEAK SURFACE TROUGH IS IN THE W GULF ALONG THE COAST OF
MEXICO FROM 19N96W TO 24N98W PRODUCING POSSIBLE LOW LEVEL
SHOWERS WITHIN 45 NM OF THE AXIS. OTHERWISE...A SURFACE RIDGE
ANCHORED BY A 1023 MB HIGH CENTERED OVER THE SE CONUS WILL
CONTINUE TO PROVIDE FAIR WEATHER THIS AFTERNOON AND PERSIST INTO
THE MIDDLE PORTION OF THE WEEK.

CARIBBEAN SEA...
THE CARIBBEAN IS DOMINATED BY AN UPPER RIDGE ANCHORED NEAR
11N56W EAST OF TRINIDAD AND TOBAGO. A DISSIPATING COLD FRONT
ENTERS THE AREA THROUGH THE WINDWARD PASSAGE NEAR 20N73W TO NW
JAMAICA NEAR 18N78W THEN WESTWARD TO 18N87W. POSSIBLE ISOLATED
SHOWERS ARE WITHIN 60 NM S OF THE FRONT. A WEAK SURFACE TROUGH
ENTERS THE AREA THROUGH THE MONA PASSAGE NEAR 18N68W ALONG
16N69W TO CABO SAN ROMAN VENEZUELA NEAR 12N70W. SCATTERED
SHOWERS AND POSSIBLE THUNDERSTORMS ARE WITHIN 150 NM EITHER SIDE
OF THE TROUGH AXIS. POCKETS OF SCATTERED SHOWERS ARE OVER THE
CENTRAL LESSER ANTILLES. SHOWERS AND POSSIBLE THUNDERSTORMS ARE
OVER PANAMA AND COSTA RICA CAUSED BY THE UPPER RIDGE DRAWING
MOISTURE N FROM A SURFACE LOW IN THE E PACIFIC. THE REMAINDER OF
THE CARIBBEAN IS ENJOYING GENERALLY FAIR WEATHER THIS AFTERNOON.
OVER THE NEXT 24 HOURS...EXPECT THE COLD FRONT TO BE BECOME MORE
DIFFUSE OVER THE WESTERN CARIBBEAN.

ATLANTIC OCEAN...
AN UPPER TROUGH COVERS THE W ATLC TO 60W SUPPORTING A COLD FRONT
THAT EXTENDS FROM 32N61W ALONG 25N64W TO THE WINDWARD PASSAGE
NEAR 20N73W WHERE IT BECOMES DISSIPATING INTO THE NW CARIBBEAN.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING FROM
25N TO BEYOND 32N BETWEEN 52W AND THE FRONT. S OF 25N...A
PRE-FRONTAL SURFACE TROUGH EXTENDS S FROM THE COLD FRONT NEAR
25N64W ALONG 21N66W TO THE MONA PASSAGE NEAR 18N68W. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 240 NM EITHER SIDE
OF THE SURFACE TROUGH FROM 21N-25N...AND SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 100 NM EITHER SIDE OF
THE TROUGH S OF 21N. A 1020 MB HIGH IS FURTHER E CENTERED NEAR
28N45W. AN UPPER TROUGH IS IN THE E ATLC N OF 10N E OF 13W
SUPPORTING A WEAK SURFACE TROUGH REMNANT OF A COLD FRONT THAT
EXTENDS FROM 31N15W ALONG 24N20W TO 20N27W. ISOLATED SHOWERS ARE
OCCURRING WITHIN 75 NM E THE TROUGH. A SHEAR LINE IS ALONG 19N
BETWEEN 37W AND 50W WITH NO SIGNIFICANT CONVECTION. A SURFACE
TROUGH WITH AN EMBEDDED SURFACE LOW EXTENDS FROM 13N53W THROUGH
THE LOW CENTER NEAR 11N54W TO INLAND OVER SURINAME NEAR 6N56W.
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE
FROM 9N-13N BETWEEN 48W AND 55W WITH MOSTLY SCATTERED SHOWERS
AND ALONG THE COAST OF SURINAME S OF 7N BETWEEN 54W AND 56W.

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

$$
MONTALVO/HUFFMAN




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