[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 12 2012

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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH REACHES THE COASTAL BORDER OF SIERRA LEONE
NEAR 7N11W. THE ITCZ CONTINUES FROM 7N11W TO 5N24W 3N37W 4N42W
AND 3N47W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE
TO ISOLATED STRONG TO THE SOUTH OF 10N TO THE EAST OF 20W...
RAINSHOWERS ARE POSSIBLE TO THE SOUTH OF 10N BETWEEN 20W AND 30W
AND ELSEWHERE TO THE SOUTH OF 10N BETWEEN 40W AND 60W...
SCATTERED MODERATE TO STRONG FROM 3N TO 6N BETWEEN 34W
AND 42W...

...DISCUSSION...

FROM THE ATLANTIC OCEAN...TO THE WEST OF THE LINE THAT PASSES
THROUGH 32N68W TO 25N75W...BEYOND CENTRAL GUATEMALA...INTO THE
GULF OF MEXICO...AND AFFECTING A PART OF THE NORTHWESTERN CORNER
OF THE CARIBBEAN SEA AND NEARBY CENTRAL AMERICA...

DEEP LAYER SOUTHWESTERLY WIND FLOW HAS REPLACED THE DEEP
LAYER TROUGH FROM 48 HOURS AGO. THAT TROUGH WAS PROVIDING
SUPPORT FOR THE GULF OF MEXICO FRONTAL BOUNDARY. A STATIONARY
FRONT PASSES THROUGH 32N77W TO 29N82W IN FLORIDA...TO 25N90W
IN THE CENTRAL GULF OF MEXICO...INTO THE SOUTHWESTERN CORNER
OF THE AREA NEAR 19N96W IN THE ISTHMUS OF TEHUANTEPEC OF
SOUTHERN MEXICO. A TROUGH IS TO THE EAST OF THE FRONT...FROM
THE FLORIDA WEST COAST NEAR 28N83W TO 25N88W...INTO THE YUCATAN
PENINSULA NEAR 20N90W. SCATTERED STRONG CONVECTION AT 12/0845 UTC
WAS COVERING THE GULF OF MEXICO AND THE YUCATAN CHANNEL FROM THE
NORTHEASTERN CORNER OF THE YUCATAN PENINSULA TO SOUTHWESTERN
FLORIDA...EAST CENTRAL COASTAL FLORIDA...AND IN THE ATLANTIC
OCEAN TO THE WEST OF THE LINE THAT PASSES THROUGH 32N74W TO THE
EAST CENTRAL FLORIDA COAST. CLOUD TOP TEMPERATURES HAVE BEEN
WARMING AND PRECIPITATION HAS BEEN WEAKENING WITH TIME...
UP TO THE PRESENT TIME OF THIS BULLETIN. RAINSHOWERS ARE POSSIBLE
WITHIN 120 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH
31N85W IN THE FLORIDA PANHANDLE...TO 25N90W IN THE CENTRAL GULF
OF MEXICO...BEYOND 21N97W AT THE MEXICO GULF COAST. THE EARLIER
PRECIPITATION THAT WAS OCCURRING TO THE SOUTH OF 17N TO THE WEST
OF 87W IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA AND IN
THE GULF OF HONDURAS HAS BEEN WEAKENING WITH TIME ALSO.

A SURFACE RIDGE PASSES THROUGH SOUTH CENTRAL TEXAS...INTO
NORTHERN MEXICO NEAR 28N101W...TO 21N98W IN COASTAL MEXICO...
TO 19N97W IN MEXICO. GALE-FORCE WINDS ARE FORECAST TO DEVELOP
IN THE GULF OF TEHUANTEPEC ON THE EASTERN PACIFIC OCEAN SIDE
OF MEXICO DURING THE NEXT 12 HOURS OR SO. PLEASE READ
THE HIGH SEAS FORECAST...MIAHSFEP2...FOR MORE DETAILS.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT
THE 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS THAT ARE
TO THE EAST OF 94W...WITHIN 120 NM TO THE WEST OF THE
STATIONARY FRONT...AND ELSEWHERE TO THE SOUTH OF 25N
TO THE WEST OF THE FRONT.

THE REST OF THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL WESTERLY-TO-SOUTHERLY WIND FLOW
COVERS THE REST OF THE NORTHWESTERN CORNER OF THE AREA...
TO THE SOUTH OF 16N TO THE WEST OF 80W. MIDDLE LEVEL
NORTHEASTERLY-TO-EASTERLY WIND FLOW MOVES FROM EAST-TO-WEST
ACROSS THE ENTIRE CARIBBEAN SEA. BROAD MIDDLE LEVEL TO UPPER
LEVEL ANTICYCLONIC WIND FLOW COVERS THE SOUTH CENTRAL CARIBBEAN
SEA...WITH THE FLOW ORIGINATING IN NORTHERN SECTIONS OF SOUTH
AMERICA.

A SURFACE RIDGE PASSES THROUGH 25N77W IN THE BAHAMAS...
ACROSS THE CAYMAN ISLANDS...TO HONDURAS AND EL SALVADOR.

THE 24-HOUR RAINFALL TOTAL FOR THE TIME PERIOD ENDING
AT 1200 UTC FOR TRINIDAD FOR EACH OF THE LAST THREE DAYS
HAS BEEN 0.38 OF AN INCH...0.53 OF AN INCH...AND
0.22 OF AN INCH. THE RAIN WAS NEAR THE SOUTHWESTERN
END OF AN ATLANTIC OCEAN SHEAR AXIS. THE SHEAR AXIS
DISSIPATED DURING THE LAST 24 HOURS.

THE MONSOON TROUGH PASSES THROUGH 8N75W IN COLOMBIA...TO 8N81W
IN SOUTHERN PANAMA...BEYOND 8N85W IN THE EASTERN PACIFIC OCEAN.
CONVECTIVE PRECIPITATION...ISOLATED MODERATE IN THE SOUTHWESTERN
CORNER OF THE CARIBBEAN SEA TO THE SOUTH OF 11N TO THE WEST
OF 80W...IN THE EASTERN PACIFIC OCEAN...SCATTERED STRONG FROM
5N TO 7N BETWEEN 79W AND 89W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE
20 TO 25 KNOT WINDS AND 8 TO 11 FOOT SEA HEIGHTS FROM
10N TO 18N TO THE EAST OF 80W FOR THE NEXT 48 HOURS OR SO.

THE ATLANTIC OCEAN...

A DEEP LAYER TROUGH PASSES THROUGH 27N15W IN THE EASTERN
ATLANTIC OCEAN...TO 25N22W...ALONG A SHEAR AXIS FROM 25N22W
TO 27N34W AND 27N39W...THE TROUGH CONTINUES FROM 27N39W
TO A 22N48W CYCLONIC CIRCULATION CENTER...TO 18N50W 14N53W
AND 11N60W NEAR THE EASTERN CARIBBEAN SEA ISLANDS.
CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED
STRONG WITHIN 300 NM ON EITHER SIDE OF 22N35W 15N41W 10N46W.
A SURFACE TROUGH IS ALONG 17N47W 15N49W 12N50W.

AN ATLANTIC OCEAN RIDGE PASSES THROUGH 33N19W...TO A 1030 MB
HIGH PRESSURE CENTER THAT IS NEAR 33N39W...TO A SECOND 1030 MB
HIGH PRESSURE CENTER THAT IS NEAR 32N55W...TO 29N67W 25N77W...
ACROSS THE CAYMAN ISLANDS IN THE CARIBBEAN SEA.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT 20 TO 25 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS
FROM 12N TO 27N TO THE EAST OF 65W...TO THE SOUTH OF 12N
TO THE EAST OF 52W...AND TO THE SOUTH OF 23N BETWEEN 65W AND
73W. EXPECT A COLD FRONT IN 24 HOURS ALONG 31N76W 26N80W.
20 TO 25 KNOT WINDS AND 8 TO 9 FOOT SEA HEIGHTS TO THE WEST
OF THE FRONT.

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

$$
MT




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