[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 311756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 31 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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.

...SPECIAL FEATURE...

TROPICAL STORM ZETA IS NEAR 25.9N 38.2W OR ABOUT 1060
MILES...1710 KM... SOUTHWEST OF THE AZORES ISLANDS AT 31/1500
UTC. ZETA IS MOVING WEST 4 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 997 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 50 KT
WITH GUSTS TO 60 KT. PLEASE REFER TO THE LATEST
FORECAST/ADVISORY LISTED UNDER THE AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. ZETA CONTINUES TO
GENERATE DEEP CONVECTION...BUT WESTERLY SHEAR IS RESTRICTING
THIS CONVECTION TO THE EASTERN SEMICIRCLE. IT APPEARS THAT THE
LOW LEVEL CENTER IS NOW EXPOSED. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS FROM 25N-27N BETWEEN 37W-38W.  SCATTERED
MODERATE CONVECTION IS ALSO SE OF THE CENTER FROM 21N-26N
BETWEEN 34W-36W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N13W 4N30W 4N40W 7N53W 6N58W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 1.5N-3N
BETWEEN 24W-28W...AND FROM 3N-7N BETWEEN 29W-46W.  SCATTERED
MODERATE CONVECTION IS ALSO OVER AND JUST NORTH OF FRENCH GUIANA
SURINAME AND GUYANA FROM 4N-7N BETWEEN 51W-57W.

...DISCUSSION...

THE GULF OF MEXICO...
WEAK SURFACE RIDGING FROM THE W ATLANTIC DOMINATES THE GULF OF
MEXICO.  A WEAK STATIONARY FRONT IS ALONG THE NW PORTION OF THE
GULF ALONG 29N924W 27N97W.  NO CONVECTION IS ALONG THE
FRONT BUT A DISTINCT WIND SHIFT IS NOTED.  IN THE UPPER
LEVELS...WESTERLY FLOW PREVAILS ACROSS THE GULF WITH A BAND OF
MAINLY HIGH CLOUDS OVER CENTRAL MEXICO AND THE W GULF W OF
90W...AND THE NE GULF N OF 26N. THE ATLC RIDGE WILL BUILD ACROSS
THE GULF FROM SOUTHERN FLORIDA TO BROWNSVILLE TEXAS TONIGHT
THROUGH MON. SOUTHERLY FLOW WILL PREVAIL THROUGHOUT THE GULF
DURING THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
15-20 KT TRADEWINDS ARE OVER THE ENTIRE CARIBBEAN SEA.  PATCHES
OF BROKEN LOW CLOUDS AND SCATTERED SHOWERS ARE ALONG THE NW
PORTION OF VENEZUELA....INCLUDING THE ABC ISLANDS.  SIMILAR
SHOWERS ARE MOVING WESTWARD ACROSS THE LESSER ANTILLES...SOUTH
OF HISPANIOLA AND OVER NICARAGUA. IN THE UPPER LEVELS...WESTERLY
FLOW PREVAILS WITH MOISTURE AND HIGH CLOUDS OVER THE YUCATAN
PENINSULA.  EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. THE
SURFACE ELY WINDS WILL CONTINUE TO BRING PATCHES OF MOISTURE
ACROSS THE COASTAL PLAINS OF NICARAGUA AND COSTA RICA.  A
SHORTWAVE TROUGH IS OVER THE NE CARIBBEAN FROM 23N58W TO 15N65W.
SUBSIDENCE/DRY UPPER AIR IS OVER HISPANIOLA AND PUERTO RICO.

THE ATLANTIC OCEAN...
T.S. ZETA...THE 27TH OF THE YEAR...REMAINS THE MAIN FEATURE OF
INTEREST IN THE EASTERN ATLANTIC WATERS. WEAK RIDGING IS PRESENT
IN THE LOWER TO MIDDLE TROPOSPHERE TO THE NORTH OF ZETA...AND
THIS STEERING SHOULD PREDOMINATE FOR THE NEXT DAY. THIS TROPICAL
CYCLONE IS THE PRIMARY SOURCE OF CONVECTION OVER THE SUBTROPICAL
E ATLC. ELSEWHERE...A COLD FRONT IS OVER THE CENTRAL ATLANTIC
ALONG 31N51W 27.5N59W. SCATTERED MODERATE CONVECTION IS N OF 30N
BETWEEN 41W-46W ASSOCIATED WITH THE COLD FRONT. A 1019 MB
SURFACE HIGH IS NEAR 27N-67W. IN THE UPPER LEVELS...A RIDGE IS
OVER THE W ATLANTIC W OF 65W.  WESTERLY FLOW COVERS MOST OF THE
CENTRAL AND EASTERN ATLC. A MIDDLE TO UPPER LEVEL TROUGH IS
ALONG 25W.

$$
GR




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