[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI JAN 21 2011

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...

ITCZ AXIS IS ANALYZED FROM LIBERIA NEAR 5N10W AND ALONG 1N20W TO
S OF THE EQUATOR W 32W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 75 NM EITHER SIDE OF THE AXIS BETWEEN 11W
AND 21W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM S OF
THE EQUATOR TO 5N BETWEEN 30W AND 40W.

...DISCUSSION...

GULF OF MEXICO...
A LONGWAVE UPPER TROUGH ACROSS THE CENTRAL UNITED STATES IS
MOVING INTO THE NW GULF OF MEXICO PROVIDING MAINLY W-SW FLOW
ALOFT THAT SUPPORTS A COLD FRONT. THE COLD FRONT ENTERS THE
AREA THROUGH CENTRAL FLORIDA NEAR 28N83W EXTENDING ALONG 26N89W
22N93W TO INLAND OVER MEXICO NEAR 18N95W. ISOLATED SHOWERS ARE
ALONG THE FRONT WITHIN 60 NM. A PRE-FRONTAL SURFACE TROUGH IS
ANALYZED FROM ACROSS FLORIDA NEAR 27N82W ALONG 25N87W 22N91W TO
SOUTHERN MEXICO NEAR 19N92W. SCATTERED SHOWERS AND THUNDERSTORMS
ARE WITHIN 125 NM SE OF THE TROUGH BETWEEN THE FLORIDA COAST
NEAR 82W AND 87W...AND ISOLATED SHOWERS ARE ALONG THE TROUGH
WITHIN 45 NM W OF 87W. BEHIND THE FRONT COLD AIR STRATUS EXTENDS
TO THE N AND W GULF COASTS. A GALE WARNING IS S OF 22N W OF 95W.
EXPECT THE FRONTAL BOUNDARY TO CONTINUE TO PUSH ACROSS THE BASIN
WITH SHOWERS ANTICIPATED AHEAD AND ALONG THE FRONT WITH STRONG
NORTHERLY WINDS BEHIND IT.

CARIBBEAN SEA...
A WEAK PRESSURE GRADIENT ACROSS THE CARIBBEAN SEA IS MAINTAINING
MODERATE TO FRESH TRADEWINDS ACROSS MUCH OF THE BASIN. MOSTLY
FAIR WEATHER IS ACROSS THE AREA DUE TO A DRY AND STABLE AIR MASS
COVERING THE BASIN WITH ZONAL WESTERLY FLOW ALOFT AROUND A BROAD
UPPER LEVEL RIDGE. HOWEVER...A SURFACE TROUGH IS ANALYZED ALONG
15N72W 13N72W TO N COLOMBIA NEAR 12N73W WITH SCATTERED SHOWERS
FROM 12N-17N BETWEEN 69W AND 73W. E OF THE TROUGH...LINES OF
POSSIBLE ISOLATED SHOWERS ARE FROM PUERTO RICO TO N VENEZUELA
BETWEEN 64W AND 67W AND FROM 13N-16N BETWEEN THE LESSER ANTILLES
AND 62W. EXPECT THE SURFACE TROUGH TO DRIFT WESTWARD BRINGING
SHOWERS WITH IT AND THE COLD FRONT OVER THE GULF OF MEXICO TO
MOVE INTO THE NW CARIBBEAN IN THE NEXT 24 HOURS.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE AREA NEAR 32N75W EXTENDING ALONG 30N77W
TO ACROSS CENTRAL FLORIDA NEAR 29N81W TO THE GULF OF MEXICO NEAR
28N83W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN
60 NM TO THE NW OF THE FRONT AND WITHIN 120 NM SE OF THE FRONT E
OF 78W. THE NE PORTION OF THE PRE-FRONTAL TROUGH OVER THE GULF
OF MEXICO IS ANALYZED FROM 29N78W TO FLORIDA NEAR 28N81W
CROSSING INTO THE GULF NEAR 27N82W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS IS WITHIN 60 NM SE OF THE
AXIS...AND BETWEEN THE TROUGH AND FRONT. THE CENTRAL ATLANTIC IS
DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH NEAR
27N41W AND A 1019 MB HIGH NEAR 29N32W. W OF THE SURFACE HIGHS...
A COLD FRONT INTERSECTS THE RIDGE ENTERING THE AREA NEAR 32N46W
EXTENDING ALONG 30N52W TO 28N58W WITH SCATTERED SHOWERS WITHIN
45 NM EITHER SIDE OF THE FRONT. E OF THE SURFACE HIGHS...
ANOTHER COLD FRONT INTERSECTS THE RIDGE ENTERING THE AREA AS AN
OCCLUDED FRONT FROM NEAR 32N15W TO 31N15W CONTINUING AS A COLD
FRONT ALONG 27N19W 25N24W TO 24N32W WITH ISOLATED SHOWERS WITHIN
60 NM EITHER SIDE OF THE FRONT.

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

$$
HUFFMAN/MONTALVO




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