[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN DEC 30 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 PASSES THROUGH COASTAL SIERRA LEONE NEAR
8N13W TO 8N15W AND 7N16W. THE ITCZ CONTINUES FROM 7N16W TO
3N25W AND 3N39W. CONVECTIVE PRECIPITATION...SCATTERED STRONG
FROM 3N TO 5N BETWEEN 30W AND 46W...WIDELY SCATTERED TO
SCATTERED MODERATE TO ISOLATED STRONG FROM THE EQUATOR IN
NORTHEASTERN BRAZIL TO 6N BETWEEN 48W AND 53W IN FRENCH GUIANA.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL RIDGE EXTENDS FROM 16N67W IN THE
CARIBBEAN SEA...ACROSS JAMAICA...THROUGH THE YUCATAN CHANNEL...
INTO THE GULF OF MEXICO...TO 22N93W IN THE SOUTHWESTERN CORNER
OF THE GULF OF MEXICO...BEYOND 22N98W IN COASTAL MEXICO.
THE WIND FLOW IS SOUTHERLY-TO-SOUTHWESTERLY TO THE WEST OF
89W...AND WESTERLY TO THE EAST OF 89W.

A SURFACE RIDGE PASSES THROUGH THE DEEP SOUTH OF TEXAS...
TO COASTAL MEXICO NEAR 21N98W...TO THE ISTHMUS OF TEHUANTEPEC
OF SOUTHERN MEXICO. GALE-FORCE WINDS ARE BLOWING IN THE GULF
OF TEHUANTEPEC...ON THE EASTERN PACIFIC OCEAN SIDE OF MEXICO.
PLEASE READ THE HIGH SEAS FORECAST...MIAHSFEP2...AND THE EASTERN
PACIFIC OCEAN TROPICAL WEATHER DISCUSSION...MIATWDEP...FOR MORE
DETAILS.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT
20 TO 25 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS TO THE
SOUTH OF 27N BETWEEN 85W AND 96W FOR THE FIRST 24 HOURS
OF THE FORECAST PERIOD.

FROM THE WESTERN ATLANTIC OCEAN INTO THE NORTHWESTERN
CARIBBEAN SEA...

A DEEP LAYER TROUGH PASSES THROUGH 32N68W TO 30N68W. THE REST
OF THE MIDDLE LEVEL TO UPPER LEVEL WIND FLOW THAT IS IN THE
ATLANTIC OCEAN TO THE NORTH OF 20N TO THE WEST OF 60W IS CLEARLY
ANTICYCLONIC. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES
THROUGH CUBA NEAR 23N80W...TO THE YUCATAN PENINSULA OF MEXICO
NEAR 19N...EVENTUALLY INTO NORTHERN GUATEMALA NEAR 17N90W.
A CLEAR LINE OF BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
POSSIBLE PRECIPITATION MARKS THE COLD FRONT. THE CLOUDS ARE
WITHIN 60 TO 90 NM ON EITHER SIDE OF THE LINE THAT PASSES
THROUGH 32N63W 28N69W...22N79W IN CUBA...TO THE COAST OF THE
YUCATAN PENINSULA NEAR 19N88W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT A GALE WARNING AT 18 HOURS INTO THE FORECAST
PERIOD...TO THE NORTH OF 30N BETWEEN THE 31N55W 25N63W 21N76W
COLD FRONT AND 63W...30 TO 40 KNOT WINDS AND 14 TO 20 FOOT
SEA HEIGHTS. THE INITIAL CONDITIONS FOR THAT SAME AREA ARE...
COLD FRONT 31N68W TO 23N80W...TO THE NORTH OF 27N TO THE WEST
OF THE COLD FRONT...20 TO 30 KNOT WINDS AND 8 TO 12 FOOT
SEA HEIGHTS...TO THE NORTH OF 27N BETWEEN THE FRONT AND 60W...
20 TO 30 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS.

THE REST OF THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL RIDGE EXTENDS FROM 16N67W
IN THE CARIBBEAN SEA...ACROSS JAMAICA...THROUGH THE
YUCATAN CHANNEL...INTO THE GULF OF MEXICO...TO 22N93W
IN THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO...
BEYOND 22N98W IN COASTAL MEXICO.

COMPARATIVELY DRIER AIR IN SUBSIDENCE COVERS THE ENTIRE AREA.

RAINSHOWERS ARE POSSIBLE IN BROKEN LOW TO MIDDLE LEVEL CLOUDS
FROM 13N TO 16N BETWEEN 67W AND 73W...AND ALSO FROM THE LINE
14N73W 12N79W 9N80W TO 18N TO THE WEST OF 73W. THE CLOUDS
ARE MOVING WESTWARD BETWEEN 67W AND 76W...AND THEN THEY
EVENTUALLY CURVE SOUTHWESTWARD WITH THE SURFACE-TO-LOW LEVEL
WIND FLOW.

THE MONSOON TROUGH PASSES THROUGH 7N74W IN COLOMBIA...THROUGH
7N81W IN PANAMA...BEYOND 8N86W INTO THE EASTERN PACIFIC OCEAN.
CONVECTIVE PRECIPITATION...RAINSHOWERS ARE POSSIBLE TO THE SOUTH
OF 12N TO THE WEST OF 80W...MOSTLY WITH THE LARGE-SCALE SURFACE-
TO-LOW LEVEL WIND FLOW. CONVECTIVE PRECIPITATION IN THE EASTERN
PACIFIC OCEAN...SCATTERED MODERATE TO STRONG FROM 4N TO 6N
BETWEEN 77W AND 80W...AND FROM 4N TO 7N BETWEEN 84W AND 93W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT
20 TO 30 KNOT WINDS AND 10 TO 12 FOOT SEA HEIGHTS FROM
11N TO 14N BETWEEN 73W AND 78W...20 TO 25 KNOT WINDS
AND 8 TO 10 FOOT SEA HEIGHTS ELSEWHERE FROM 10N TO 17N
TO THE WEST OF 70W. EXPECT 20 TO 25 KNOT WINDS AND 9 FOOT
SEA HEIGHTS TO THE NORTH OF THE 22N82W 19N87W COLD FRONT.

THE REST OF THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 26N32W. A TROUGH EXTENDS FROM THE 26N32W CENTER TO 19N40W
16N50W AND 14N60W AT THE EDGE OF THE EASTERN CARIBBEAN SEA
ISLANDS.

A SURFACE TROUGH IS ALONG 32N41W 27N44W 21N45W. A SMALL SWIRL OF
LOW CLOUDS AT THE SURFACE APPEARS NEAR 22N45W. IT IS LIKELY THAT
THIS SWIRL IS THE REMNANT OF THE 1018 MB LOW PRESSURE THAT WAS
PART OF THE 30/0600 UTC SURFACE MAP ANALYSIS...NEAR 23N44W.
RAINSHOWERS ARE POSSIBLE TO THE NORTH OF 20N BETWEEN 36W AND
50W...AND FROM 15N TO 20N BETWEEN 40W AND 60W.

A SURFACE RIDGE PASSES THROUGH 32N23W IN THE EASTERN ATLANTIC
OCEAN...TO 32N32W...33N42W 32N45W...TO 23N58W AND 11N60W JUST
TO THE EAST OF THE EASTERN CARIBBEAN SEA ISLANDS.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT...20 KNOT WINDS OR LESS AND 8 TO 10 FOOT
SEA HEIGHTS TO THE NORTH OF 24N BETWEEN 35W AND 50W.

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

$$
MT




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