[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 310604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED DEC 31 2014

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 SOUTHERN COASTAL SECTIONS OF
SIERRA LEONE NEAR 7N12W...TO 7N18W AND 6N24W. THE ITCZ CONTINUES
FROM 6N24W TO 5N32W AND 4N39W. CONVECTIVE PRECIPITATION...
SCATTERED STRONG WITHIN 120 NM ON EITHER SIDE OF 10N19W 6N24W
3N31W...TO THE EQUATOR ALONG 33W.

...DISCUSSION...

...THE GULF OF MEXICO...

MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW SPANS THE
GULF OF MEXICO. A SHALLOW AND SLOWLY-MOVING COLD FRONT PASSES
THROUGH LAKE OKEECHOBEE IN SOUTH FLORIDA...TO 24N87W. A
STATIONARY FRONT CONTINUES FROM 24N87W TO 22N94W...TO 18N95W IN
THE WESTERN ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO. BROKEN TO
OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE TO THE
NORTH OF THE FRONTAL BOUNDARY.

A SURFACE RIDGE PASSES THROUGH SOUTH CENTRAL TEXAS...THROUGH THE
DEEP SOUTH OF TEXAS...ALONG THE COAST OF MEXICO...TO 21N96W...
INTO THE WESTERN ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO.

FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N
TO THE WEST OF 88W...

LOW LEVEL CLOUD CEILINGS ARE BEING REPORTED AT...VIRTUALLY ALL
THE ICAO PLATFORM SITES...EXCEPT FOR KGBK WITH TEMPORARILY
CLEARING SKIES IN THE LOWER LEVELS OF THE ATMOSPHERE...AND KEHC
WITH FAIR SKIES FOR SEVERAL OBSERVATIONS DURING THE LAST 12
HOURS.

LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF
THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

LOW LEVEL CLOUD CEILINGS COVER THE AREA FROM THE DEEP SOUTH OF
TEXAS TO PERRY IN THE FLORIDA PANHANDLE. CLEARING SKIES ARE
BEING OBSERVED IN THE HOUSTON METROPOLITAN AREA AND SURROUNDING
SMALLER COMMUNITIES...INCLUDING BEAUMONT-PORT ARTHUR. LOW LEVEL
CLOUD CEILINGS ARE BEING REPORTED IN THE TAMPA-ST. PETERSBURG
METROPOLITAN AREA.

...THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW SPANS THE
CARIBBEAN SEA. A MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC
CIRCULATION CENTER IS NEAR 19N86W IN THE NORTHWESTERN CORNER OF
THE CARIBBEAN SEA. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS
APPARENT IN WATER VAPOR IMAGERY ACROSS THE AREA.

ONE MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 64W
FROM 15N SOUTHWARD. A SECOND MIDDLE LEVEL TO UPPER LEVEL
INVERTED TROUGH IS ALONG 75W/76W FROM 15N SOUTHWARD. CYCLONIC
WIND FLOW COVERS THE AREA FROM 16N SOUTHWARD BETWEEN 60W AND
80W.

RAINSHOWERS ARE POSSIBLE FROM 17N SOUTHWARD BETWEEN 60W AND
62W...FROM 14N NORTHWARD BETWEEN 62W AND 70W...FROM 15N TO 20N
FROM 80W WESTWARD...AND ELSEWHERE FROM 17N SOUTHWARD BETWEEN 70W
AND CENTRAL AMERICA MOVING INTO THE SOUTHWESTERN CORNER OF THE
CARIBBEAN SEA. THE 24-HOUR RAINFALL TOTAL IN INCHES FOR THE
PERIOD ENDING AT 31/0000 UTC...ACCORDING TO THE PAN AMERICAN
TEMPERATURE AND PRECIPITATION TABLES ARE...0.06 IN CURACAO...
AND 0.16 IN GUADELOUPE.

THE MONSOON TROUGH IS ALONG 9N75W IN COLOMBIA...THROUGH 8N81W IN
PANAMA...TO 7N85W. THE ITCZ CONTINUES WESTWARD INTO THE EASTERN
PACIFIC OCEAN. CONVECTIVE PRECIPITATION...RAINSHOWERS FROM
TRADEWIND FLOW ARE POSSIBLE IN THE SOUTHWESTERN CORNER OF THE
CARIBBEAN SEA...FROM 15N SOUTHWARD FROM 75W WESTWARD.

...HISPANIOLA...

MIDDLE LEVEL TO UPPER LEVEL NORTHEASTERLY WIND FLOW IS MOVING
ACROSS HISPANIOLA. A MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC
CIRCULATION CENTER IS NEAR 19N86W IN THE NORTHWESTERN CORNER OF
THE CARIBBEAN SEA. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS
APPARENT IN WATER VAPOR IMAGERY ACROSS HISPANIOLA.

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 71W FROM
THE DOMINICAN REPUBLIC TO 23N IN THE ATLANTIC OCEAN.
COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR
IMAGERY ON TOP OF THE AREA OF THE TROUGH. A SURFACE TROUGH IS
ALONG 26N69W TO 23N70W AND 20N71W. CONVECTIVE PRECIPITATION...
BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS
ARE FROM 21N TO 27N BETWEEN 67W AND 72W.

CLOUD CONDITIONS AND PREVAILING WEATHER...FOR THE DOMINICAN
REPUBLIC...FEW LOW LEVEL CLOUDS ARE IN SANTO DOMINGO AND LA
ROMANA. SCATTERED LOW LEVEL CLOUDS AND SCATTERED MIDDLE LEVEL
CLOUDS ARE IN PUNTA CANA. SCATTERED LOW LEVEL CLOUDS ARE IN
SANTIAGO. FEW LOW LEVEL CLOUDS AND SCATTERED MIDDLE LEVEL CLOUDS
ARE IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT NORTH-TO-NORTHWEST
WIND FLOW WILL CROSS HISPANIOLA DURING THE NEXT 48 HOURS. A
RIDGE WILL EXTEND FROM PANAMA TO THE YUCATAN PENINSULA. THE GFS
MODEL FORECAST FOR 500 MB SHOWS THAT NORTH-TO-NORTHEAST WIND
FLOW WILL CROSS HISPANIOLA. AN ANTICYCLONIC CIRCULATION CENTER
WILL START IN THE WATERS THAT ARE BETWEEN THE TURKS AND CAICIOS
ISLANDS AND HISPANIOLA...AND IT EVENTUALLY WILL BE PART OF A
MERGED ANTICYCLONIC CIRCULATION CENTER THAT WILL END UP IN THE
SOUTHEASTERN GULF OF MEXICO NEAR 25N84W. THE GFS MODEL FORECAST
FOR 700 MB SHOWS THAT SOUTHEASTERLY WIND FLOW WILL CROSS
HISPANIOLA. AN INVERTED TROUGH WILL BE TO THE WEST OF
HISPANIOLA.

...THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 31N20W TO
25N22W AND 22N31W. A SHEAR AXIS CONTINUES FROM 22N31W TO 20N43W.
A TROUGH CONTINUES FROM 20N43W TO 17N50W...TO A 19N43W...TO A
CUT-OFF CYCLONIC CIRCULATION CENTER THAT IS NEAR 13N51W...TO
8N59W AT THE COAST OF GUYANA...AND 7N62W IN NORTHEASTERN
VENEZUELA. MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW
AND MULTILAYERED MOISTURE COVER THE ATLANTIC OCEAN TO THE EAST
OF THE 31N20W 7N62W TROUGH. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED TO SCATTERED MODERATE FROM 10N TO 20N BETWEEN 30W AND
50W...AND FROM 10N SOUTHWARD BETWEEN 35W AND 55W. A COLD FRONT
EXTENDS FROM A 1022 MB LOW PRESSURE CENTER THAT IS NEAR 30N21W...
TO 25N22W. THE COLD FRONT IS DISSIPATING FROM 25N22W TO 22N26W.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED
MODERATE AND ISOLATED STRONG FROM 28N NORTHWARD BETWEEN 10W AND
20W.

A SHALLOW COLD FRONT IS PASSING THROUGH 32N71W TO LAKE
OKEECHOBEE IN SOUTH FLORIDA. THE 24-HOUR RAINFALL TOTAL IN
INCHES FOR THE PERIOD ENDING AT 31/0000 UTC...ACCORDING TO THE
PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES ARE...0.06 IN
BERMUDA.

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 71W FROM
THE DOMINICAN REPUBLIC TO 23N IN THE ATLANTIC OCEAN.
COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR
IMAGERY ON TOP OF THE AREA OF THE TROUGH. A SURFACE TROUGH IS
ALONG 26N69W TO 23N70W AND 20N71W. CONVECTIVE PRECIPITATION...
BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS
ARE FROM 21N TO 27N BETWEEN 67W AND 72W.

A WESTERN ATLANTIC OCEAN SURFACE RIDGE IS ALONG 31N27W TO A 1029
MB HIGH PRESSURE CENTER THAT IS NEAR 28N40W...TO 26N61W.

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

$$
MT


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