[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU APR 04 2013

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 EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC BY SIERRA LEONE NEAR 7N12W AND CONTINUES ALONG 4N14W TO
EQ19W WHERE THE ITCZ BEGINS AND CONTINUES ALONG EQ25W EQ33W
1S40W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
ARE FROM 1S TO 6N BETWEEN 8W AND 40W.

...DISCUSSION...

GULF OF MEXICO...
A LOW PRESSURE SYSTEM CONTINUES OVER THE NE GULF. THE 1013 MB
LOW ASSOCIATED TO THIS SYSTEM IS LOCATED IN THE FLORIDA
PANHANDLE NEAR 30N84W. A COLD FRONT EXTENDS SW FROM THE LOW
ALONG 28N86W 26N89W 23N92W 20N94W. RADAR IMAGERY SHOW NUMEROUS
RAINSHOWERS AND THUNDERSTORMS FROM TAMPA TO FORT MYERS ALSO
EXTENDING WITHIN 200 NM FROM THE WEST FLORIDA COASTLINE FROM 25N-
29N. SCATTERED SHOWERS ARE OCCURRING ALONG THE REMAINING FRONTAL
BOUNDARY. IN THE MIDDLE-UPPER LEVELS...THIS SYSTEM IS BEING
SUPPORTED BY A CUT-OFF LOW LOCATED OVER THE SOUTHERN PLAINS AND
ITS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE. A
PREFRONTAL SURFACE TROUGH IS JUST WEST OF THE YUCATAN PENINSULA
EXTENDING FROM 24N89W 21N90W 18N91W. SCATTERED SHOWERS ARE
POSSIBLE ALONG THIS TROUGH AS WELL AS 10 NM EITHER SIDE OF THE
AXIS. N-NW WIND RANGING FROM 15-25 KT SPREAD OVER THE WESTERN
GULF WEST OF THE COLD FRONT WHILE S-SW WIND OF 15-20 KT DOMINATE
THE EASTERN GULF E OF 90W. BROKEN TO OVERCAST SKIES ARE IN THE
NW GULF N OF 25N AS WELL AS ALONG THE THE EASTERN COAST OF
MEXICO BUT RAINSHOWERS ACTIVITY IS LIMITED DUE TO THE PRESENCE
OF DRY AIR IN THE MIDDLE-UPPER LEVELS W OF 86W. OVER THE COURSE
OF 24 HOURS...A STRONG JET OVER THE GULF EXTENDING TO THE
WESTERN CARIBBEAN WILL DRIFT THE FRONTAL SYSTEM TO OVER WEST
ATLC WITH THE TAIL OF IT EXTENDING TO THE FLORIDA STRAITS AND
THE WESTERN CARIBBEAN. N-NW FLOW RANGING FROM 15-20 KT WILL
BUILD OVER THE GULF AFTER THE PASSAGE OF THIS FRONT.

CARIBBEAN SEA...
STRONG PRESSURE GRADIENT CONTINUES OVER THE CARIBBEAN
MAINTAINING EASTERLY TRADEWINDS OF 15-20 KT ACROSS MOST OF THE
BASIN...HOWEVER STRONGER WINDS UP TO 30 KT MAY BE FOUND OVER THE
CENTRAL CARIBBEAN S OF LA HISPANIOLA. THIS PRESSURE GRADIENT IS
DUE TO THE LOWER PRESSURE OVER COLOMBIA AND THE SURFACE RIDGE
OVER THE W ATLC. IN THE MIDDLE-UPPER LEVEL...A BROAD RIDGE
ANCHORED BY A HIGH CENTERED OVER THE COLOMBIA-VENEZUELA BORDER
COVERS THE ENTIRE CARIBBEAN. THE WESTERN PERIPHERY OF THIS RIDGE
IS ADVECTING MOISTURE FROM THE E PACIFIC WHICH IS SUPPORTING LOW
LEVEL CLOUDINESS AND HAZE OVER THE WESTERN CARIBBEAN W OF 80W...
ISOLATED SHOWERS ARE POSSIBLE WITHIN THIS REGION. RAINSHOWERS
ACTIVITY CAN ALSO BE FOUND IN THE SOUTHERN CARIBBEAN S OF 13N IN
ASSOCIATION TO THE E PACIFIC MONSOON TROUGH. A SCREAMING EAGLE
IS OVER THE LESSER ANTILLES PRODUCING RAINSHOWERS FROM ST KITTS
TO ST LUCIA. CLEAR SKIES ARE OVER THE REMAINDER OF THE CARIBBEAN
BEING ASSISTED BY DRY AIR SUBSIDENCE FROM THE MIDDLE-UPPER
LEVELS. OVER THE COURSE OF 24 HOURS...THE COLD FRONT CURRENTLY
OVER THE CENTRAL-EASTERN GULF WILL DRIFT EASTWARD TO THE W ATLC
AND ITS TAIL WILL BE REACHING THE W CARIBBEAN FROM WESTERN CUBA
TO HONDURAS. EASTERLY TRADEWINDS ARE EXPECTED TO CONTINUE E OF
THE APPROACHING FRONT.

ATLANTIC OCEAN...
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE W ATLC N
OF 26N AND WITHIN 130 NM OF THE E FLORIDA COAST RELATED WITH THE
FRONTAL SYSTEM IN THE GULF OF MEXICO WITH ASSOCIATED LOW OVER
THE FLORIDA PANHANDLE. THIS CONVECTION IS BEING SUPPORTED BY
MIDDLE-UPPER LEVEL DIVERGENCE. A COLD FRONT EXTENDS ALONG 30N51W
27N55W TO 25N58W WHERE IT TRANSITIONS TO A STATIONARY FRONT
ALONG 24N61W 23N64W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 70 NM
EITHER SIDE OF THIS FRONTAL BOUNDARY. THE FRONT IS BEING
SUPPORTED IN THE MIDDLE-UPPER LEVELS BY A BROAD TROUGH COVERING
THE W ATLC AND A PORTION OF THE CENTRAL ATLC. SURFACE RIDGING
DOMINATES THE REMAINDER OF THE ATLC N OF 18N E OF THE FRONT.
WITHIN THE COURSE OF 24 HOURS...THE FRONT IN THE GULF OF MEXICO
WILL DRIFT TO THE W ATLC OVER THE BAHAMAS.

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

$$
NR


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