[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU DEC 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL LIBERIA NEAR 6N10W
TO 4N14W. THE ITCZ CONTINUES FROM 4N14W TO 1N20W...REACHING
THE EQUATOR ALONG 27W...FROM THE EQUATOR TO 1N BETWEEN 27W
AND 42W...INTO NORTHEASTERN BRAZIL NEAR 1S48W.
CONVECTIVE PRECIPITATION...SCATTERED STRONG WITHIN 30 NM
ON EITHER SIDE OF 6N47W 7N50W 8N51W 10N54W 11N53W.

...DISCUSSION...

THE GULF OF MEXICO...

MIDDLE LEVEL SOUTHWESTERLY WIND FLOW COVERS THE AREA THAT
IS TO THE EAST OF THE LINE THAT RUNS FROM THE FLORIDA
BIG BEND BEYOND THE SOUTHWESTERN CORNER OF THE AREA. MIDDLE
LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW MOVES FROM
FLORIDA AND TEXAS INTO THE GULF OF MEXICO. COMPARATIVELY DRIER
AIR IN SUBSIDENCE...IN WATER VAPOR SATELLITE IMAGERY...COVERS
THE ENTIRE AREA. A COLD FRONT IS IN TEXAS RIGHT NOW...HEADING
FOR THE TEXAS GULF COAST.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT THE
GALE WARNING...AT 12 HOURS...A 30N92W 24N98W COLD FRONT...
30 TO 35 KNOT WINDS AND 8 FOOT SEA HEIGHTS TO THE WEST OF THE
FRONT TO THE SOUTH OF 28N. EXPECT 20 TO 30 KNOT WINDS AND SEA
HEIGHTS TO 8 FEET ELSEWHERE TO THE WEST OF THE FRONT.

THE CARIBBEAN SEA...

BROAD MIDDLE LEVEL SOUTHEASTERLY WIND FLOW COVERS THE AREA.

MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW MOVES FROM
THE SOUTHWESTERN CORNER OF THE AREA...AND FROM COLOMBIA AND
VENEZUELA NORTHWARD...IN ORDER TO BE TO THE SOUTH OF 14N.
COMPARATIVELY DRIER AIR IN SUBSIDENCE...IN WATER VAPOR
SATELLITE IMAGERY...COVERS THE ENTIRE AREA.

BROKEN LOW LEVEL TO MIDDLE LEVEL CLOUDS AND POSSIBLE RAINSHOWERS
ARE TO THE SOUTH OF 18N BETWEEN 60W AND 64W...AND ELSEWHERE
TO THE SOUTH OF 17N TO THE WEST OF 65W.

THE SURFACE PRESSURE GRADIENT CONTINUES TO BE
COMPARATIVELY WEAK ACROSS THE AREA.

THE MONSOON TROUGH PASSES THROUGH 8N74W IN COLOMBIA...TO 6N78W
AT THE COLOMBIA COAST OF THE EASTERN PACIFIC OCEAN...ALONG THE
EASTERN PACIFIC OCEAN COASTS OF PANAMA AND COSTA RICA...BEYOND
8N85W IN THE EASTERN PACIFIC OCEAN. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO ISOLATED STRONG TO THE SOUTH OF 11N
TO THE WEST OF 79W...AND ALONG THE PANAMA COAST...ON THE
EASTERN PACIFIC OCEAN SIDE...NEAR 8N BETWEEN 78W AND 79W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT
20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS IN 6 HOURS...
FROM 11N TO 13N BETWEEN 70W AND 77W.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N56W
TO 27N57W. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES
THROUGH 32N50W TO 26N60W AND 24N68W. THE FRONT IS DISSIPATING
FROM 24N68W TO 24N73W. CONVECTIVE PRECIPITATION...BROKEN
TO OVERCAST LOW LEVEL AND MIDDLE LEVEL CLOUDS AND POSSIBLE
PRECIPITATION MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION
FROM THE CARIBBEAN SEA ISLANDS TO 24N BETWEEN 57W AND 70W...
WITHIN 90 NM ON EITHER SIDE OF 24N59W 29N51W BEYOND 32N48W...
TO THE NORTH OF 18N BETWEEN 44W AND 54W.

A 1020 MB HIGH PRESSURE CENTER IS NEAR 30N78W. BROAD SURFACE
ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH
OF 32N50W 24N68W COLD FRONT.

A MIDDLE LEVEL TO UPPER LEVEL RIDGE IS ALONG 20N63W BEYOND
32N50W.

A SURFACE RIDGE EXTENDS FROM A 1020 MB HIGH PRESSURE CENTER
THAT IS NEAR 32N36W...TO 27N44W AND 22N58W.

A SURFACE RIDGE PASSES THROUGH 31N14W...TO 27N27W 22N48W
AND 23N58W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT...THE GALE WARNING IN THE CENTRAL ATLANTIC OCEAN.

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

$$
MT





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