[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011735
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT JAN 01 2011

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

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

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE NORTHERN COAST LIBERIA NEAR
06N11W WESTWARD ALONG 4N20W 4N30W 5N40W 2N51W. CLUSTERS OF
SCATTERED WEAK TO MODERATE CONVECTION ARE WITHIN 130 NM NORTH OF
THE AXIS BETWEEN 30W AND 45W. SIMILAR ACTIVITY IS WITHIN 70 NM
ON EITHER SIDE OF THE AXIS BETWEEN 25W AND 30W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES SW FLOW ALOFT ACROSS THE BASIN
...DRAWING UPPER LEVEL MOISTURE FROM THE EAST TROPICAL PACIFIC
INTO THE GULF. A BROAD UPPER TROUGH IS MOVING ACROSS THE CONUS.
EMBEDDED IN THIS SYSTEM...AN UPPER LEVEL LONGWAVE IS MOVING NE
ACROSS THE NW GULF SUPPORTING A COLD FRONT CURRENTLY ANALYZED
FROM MORGAN CITY IN LOUISIANA TO VERACRUZ MEXICO ALONG 29N91W
25N94W 19N96W. NORTH WINDS UP TO NEAR GALE FORCE ARE OBSERVED
BEHIND THE FRONT N OF 25N. SATELLITE DERIVED WINDS AND SFC OBS
ACROSS THE GULF INDICATE 15 KT TO 25 KT RETURN FLOW ELSEWHERE
AHEAD OF THE FRONT. THIS FLOW IS ADVECTING A WARM AND MOIST
AIRMASS ACROSS THE CENTRAL BASIN N OF 23N BETWEEN 85W AND THE
FRONT. IN RESPONSE...MOSAIC DOPPLER RADAR IMAGERY INDICATES
SCATTERED HEAVY SHOWERS AND ISOLATED THUNDERSTORMS QUICKLY
MOVING INLAND INTO LOUISIANA...MISSISSIPPI...ALABAMA...AND THE
FLORIDA PANHANDLE BETWEEN 87W AND 92W. THE EASTERN GULF E OF 87W
IS UNDER MOSTLY FAIR WEATHER CONDITIONS THIS AFTERNOON. EXPECT
STRONG CONVECTION TO CONTINUE TO DEVELOP ACROSS MOST OF THE
GULF...AHEAD OF THE COLD FRONT IN THE NEXT 24 HOURS.

CARIBBEAN SEA...
THE SURFACE RIDGE OVER THE W ATLC COVERS A GREAT PORTION OF THE
CARIBBEAN PROVIDING 15-25 KT SFC ANTI-CYCLONIC FLOW N OF 12N. A
REMNANT CLOUD/SHEAR LINE EXTENDS ACROSS THE SOUTHERN CARIBBEAN
FROM NEAR GRENADA IN THE LEEWARD ISLANDS TO ACROSS THE
NETHERLANDS ANTILLES CONTINUING WESTWARD TO NEAR THE COAST OF
COSTA RICA NEAR 10N82W. LOW LEVEL CONFLUENCE BETWEEN NE WINDS
AND TRADEWINDS ALONG THE SHEAR LINE ARE GENERATING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 55 NM ON EITHER SIDE
OF THE SHEAR AXIS. THE UPPER LEVELS OF THE CARIBBEAN ARE
DOMINATED BY A BROAD UPPER LEVEL RIDGE GIVING THE CARIBBEAN A
DRY WSW FLOW ALOFT...PROVIDING FAIR WEATHER CONDITIONS TO THE
REMAINDER OF THE BASIN.

ATLANTIC OCEAN...
A BROAD/DEEP TROUGH COVERS MOST OF THE N ATLC THIS AFTERNOON.
THE SOUTHERN EXTREMITY OF THE TROUGH CARRIES A SET OF UPPER
WAVES SUPPORTING A VARIETY OF BOUNDARIES EXTENDING INTO THE
DISCUSSION AREA ACROSS THE CENTRAL ATLC. THE FURTHER EAST
BOUNDARY IS ANALYZED AS A SURFACE TROUGH ALONG 35N27W 27N32W
22N39W...BECOMING A REMNANT CLOUD/SHEAR LINE ALONG 20N50W 12N60W
INTO THE SOUTHERN CARIBBEAN. BEHIND THIS BOUNDARY...A COLD FRONT
EXTENDS SW ALONG 32N31W 26N35W 23N42W...BECOMING A DISSIPATING
STATIONARY FRONT TO 2056W. AT LAST...A DEVELOPING COLD FRONT IS
ANALYZED ALONG 32N37W 29N41W 27N46W. THE COMBINATION OF THESE
BOUNDARIES ARE GENERATING SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION N OF 23N BETWEEN 25W AND 35W. THIS AREA OF CONVECTION
IS FURTHER ENHANCED ALOFT BY AN AREA OF UPPER LEVEL DIFFLUENCE
NOTED ON WATER VAPOR IMAGERY N OF 25N BETWEEN 23W AND 35W.
OTHERWISE...SCATTERED WEAK CONVECTION IS WITHIN 35 NM EITHER
SIDE OF THE SURFACE TROUGH AND SHEAR LINE S OF 23N. SURFACE
RIDGING IS ELSEWHERE ACROSS THE WESTERN AND FAR EASTERN REGIONS
OF THE ATLC ANCHORED BY A 1027 MB HIGH NEAR 31N71W AND A 1025 MB
NEAR 34N15W.

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

$$

GARCIA



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