[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 21 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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS INLAND OVER SOUTH AMERICA ALONG 72W TO THE
SOUTH OF 10N MOVING W AT 5-10 KT. THE WAVE EXTENDS ACROSS W
VENEZUELA AND E COLOMBIA TO NEAR 2N. EXCEPT FOR CYCLONIC
TURNING IN THE VICINITY OF THE WAVE AXIS NOTED ON VISIBLE
SATELLITE IMAGERY...WAVE HAS BECOME DIFFICULT TO DEPICT.
SCATTERED MODERATE-STRONG CONVECTION IS WITHIN 150/200 NM ON
EITHER SIDE OF THE AXIS.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 6N10W
WESTWARD ALONG 2N20W 2N30W 4N40W 6N50W INTO FRENCH GUIANA NEAR
5N53W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
150 NM OF THE COASTAL WATERS OF W AFRICA FROM 4N-12N. SIMILAR
CONVECTION IS FROM THE EQUATOR TO 8N BETWEEN 17W-27W. SCATTERED
WEAK TO MODERATE CONVECTION IS ELSEWHERE WITHIN 100 NM ON EITHER
SIDE OF THE ITCZ...INCLUDING THE COASTS OF FRENCH GUIANA...
SURINAME...AND GUYANA.

...DISCUSSION...

GULF OF MEXICO...
A MID-UPPER LEVEL RIDGE COVERS THE GULF THIS EVENING...PROVIDING
DRY SUBSIDENT AIR ALOFT ACROSS THE AREA. THE RIDGE SUPPORTS A
1017 MB HIGH CENTERED OVER THE NE GULF NEAR 29N85W. WHILE LIGHT
AND VARIABLE WINDS ARE OBSERVED NEAR THE HIGH CENTER...SE WINDS
10-15 KT ARE ELSEWHERE S OF 27N W OF 87W. HAZY SKIES ARE NOTED
ACROSS THE WESTERN HALF OF THE GULF W OF 90W ON VISIBLE
SATELLITE IMAGERY...DUE TO SEVERAL WILD FIRES IN SOUTHERN MEXICO
AND THE YUCATAN PENINSULA. SURFACE OBSERVATIONS ACROSS THE TEXAS
COAST ARE REPORTING LOW CEILINGS WITH VISIBILITIES DOWN TO 2.5
SM DUE TO THE CONCENTRATION OF HAZE IN THIS REGION. WEATHER
CONDITIONS ACROSS THE GULF ARE EXPECTED TO REMAIN CONSTANT OVER
THE NEXT 24 HOURS.

CARIBBEAN SEA...
WATER VAPOR IMAGERY INDICATES A SLOW MOVING UPPER LEVEL TROUGH
OVER THE NW PORTION OF THE CARIBBEAN SEA. DRY SUBSIDENT AIR
ALOFT ACCOMPANIES THE UPPER TROUGHING W OF 75W. THE UPPER LEVEL
TROUGH IS INDUCING BROAD CYCLONIC TURNING COVERING THE CENTRAL
BASIN. THIS SCENARIO IS SUPPORTING SCATTERED SHOWERS AND
THUNDERSTORMS BETWEEN 67W-73. A SURFACE TROUGH IS ANALYZED
WITHIN THIS REGION OF CONVECTION...FROM 17N72W TO 11N71W. THE
CONVECTION IS FURTHER SUPPORTED BY UPPER LEVEL DIFFLUENCE
EXTENDING FROM THE SW ATLC INTO THE NE AND N CENTRAL CARIBBEAN.
THE SURFACE TROUGH HAS DISRUPTED NORMAL EASTERLY TRADES ACROSS
THE CENTRAL PORTION OF THE BASIN...AND GLOBAL MODEL GUIDANCE
SUGGEST THIS SYNOPTIC SETUP WILL REMAIN IN PLACE FOR THE NEXT
24-48 HOURS.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY SHOWS A DEEP LAYERED LOW/TROUGH OVER THE
WESTERN N ATLC WITH MID-UPPER LEVEL TROUGHING EXTENDING SW
ACROSS THE W ATLC INTO THE NW CARIBBEAN SEA. THIS SYSTEM
SUPPORTS A COLD FRONT THAT ENTERS THE REGION ALONG 32N66W TO
30N70W GENERATING A FEW SHOWERS WITHIN 20 NM EAST OF IT. A BROAD
AREA OF SCATTERED SHOWERS AND THUNDERSTORMS IS FOUND FARTHER
EAST N OF 18N BETWEEN 52W-65W...ASSOCIATED TO BROAD UPPER LEVEL
DIFFLUENCE EXTENDING FROM THE SW ATLC INTO THE NE AND N CENTRAL
CARIBBEAN. WITHIN THIS AREA OF CONVECTION...A SURFACE TROUGH IS
ANALYZED FROM 26N59W TO 21N63W. A SECONDARY TROUGH IS ANALYZED
FROM 29N53W TO 26N55W. SURFACE RIDGING COVERS THE REMAINDER OF
THE EASTERN ATLC E OF 50W...PROVIDING FAIR WEATHER CONDITIONS
ACROSS THE AREA. GLOBAL MODEL GUIDANCE SUGGEST THE SYNOPTIC
SETUP ACROSS THE ATLC WILL REMAIN IN PLACE FOR THE NEXT 24-48
HOURS.

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

$$

GARCIA


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