000
AXNT20 KNHC 071126
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 AM EDT SAT MAY 07 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1030 UTC.

...ITCZ...

ITCZ AXIS EXTENDS SW FROM THE COAST OF SIERRA LEONE IN WEST 
AFRICA ALONG 8N13W 4N20W 1N30W EQ40W INTO NE BRAZIL NEAR 2S47W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 150 
NM ON EITHER SIDE OF THE AXIS W OF 20W. ISOLATED MODERATE 
CONVECTION IS ALONG THE AXIS E OF 20W. 

...DISCUSSION...

GULF OF MEXICO...
WESTERLY ZONAL FLOW ALOFT IS ACROSS THE DISCUSSION AREA THIS 
EVENING WITH AN UPPER LEVEL 110 KT JET STREAK PASSING OVER 
NORTHERN FLORIDA. EMBEDDED IN THIS SYSTEM...AN UPPER LEVEL SHORT 
WAVE MOVES OFF THE S-EASTERN CONUS SEABOARD SUPPORTING A 
WEAKENING COLD FRONT THAT EXTENDS ACROSS CENTRAL FLORIDA AND 
ENTERS THE GULF AS A DISSIPATING STATIONARY FRONT ALONG 26N82W 
TO 26N88W. THIS FEATURE IS BRINGING ISOLATED WEAK CONVECTION 
OVER THE CENTRAL GULF FROM 25N-28N BETWEEN 86W-92W. SURFACE 
RIDGING IS N OF THE BOUNDARY AROUND A 1016 MB HIGH NEAR 28N86W. 
THIS FEATURE COMBINED WITH DRY AIR IN THE MID LEVELS IS 
PROVIDING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE REMAINDER 
OF THE DISCUSSION AREA. THE FRONTAL SYSTEM IS EXPECTED TO 
DISSIPATE TODAY AFTERNOON AS SURFACE RIDGING BUILDS IN ITS 
WAKE.
 
CARIBBEAN SEA...
MUCH OF THE NW CARIBBEAN IS UNDER THE INFLUENCE OF DRY AIR AND 
SUBSIDENCE SUPPORTING FAIR WEATHER CONDITIONS ACROSS THIS AREA. 
AN ELONGATED AREA OF CONSIDERABLE LOW LEVEL MOISTURE CONTINUES 
TO LINGER OVER THE SE CARIBBEAN FROM 13N-16N E OF 74W. WITHIN 
THIS AREA OF MOISTURE...SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS COVER THE AREA INCLUDING THE LESSER ANTILLES. 
SIMILAR CONVECTION IS FOUND OVER THE WESTERN COASTAL WATERS OF 
HAITI TO EASTERN JAMAICA. THE TRADE WINDS ARE BANKING LOW LEVEL 
MOISTURE WITH SCATTERED SHOWERS NEAR THE COASTAL WATERS OF COSTA 
RICA... PANAMA...AND NW COLOMBIA W OF 75W. OTHERWISE...THE 
REMAINDER OF THE CARIBBEAN IS UNDER FAIR WEATHER CONDITIONS DUE 
TO STRONG SUBSIDENCE AND DRY AIR ALOFT NOTED ON WATER VAPOR 
IMAGERY. MOISTURE LEVELS ARE EXPECTED TO REMAIN HIGH ACROSS THE 
SRN CARIBBEAN OVER THE NEXT COUPLE OF DAYS INCREASING THE CHANCE 
OF SHOWER ACTIVITY.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORT WAVE MOVES OFF THE S-EASTERN CONUS SEABOARD 
SUPPORTING A COLD FRONT THAT EXTENDS INTO THE AREA ALONG 30N76W 
TO THE FLORIDA COAST NEAR 27N80W. SCATTERED SHOWERS ARE WITHIN 
70 NM EAST OF THE FRONT N OF 28N. A BROAD UPPER LEVEL RIDGE IS 
TO THE E OF THE FRONT SUPPORTING FAIR WEATHER CONDITIONS W OF 
55W. FARTHER EAST...A BROAD UPPER LEVEL CYCLONIC CIRCULATION 
REMAINS IN THE CENTRAL ATLC...SUPPORTING ITS SURFACE LOW 
REFLECTION...AN OCCLUDED 1010 MB LOW NEAR 31N49W. A SERIES OF 
FRONTAL BOUNDARIES ARE ASSOCIATED WITH THE SYSTEM. THE OUTERMOST 
SURFACE TROUGH IS ALONG 30N38W 22N41W 16N50W CONTINUING AS A 
SHEAR LINE TO E OF THE WINDWARD ISLANDS NEAR 14N60W. A LARGE 
AREA OF SCATTERED SHOWERS IS E OF THIS TROUGH N OF 22N BETWEEN 
30W-40W. A SECOND SURFACE TROUGH EXTENDS ALONG 30N44W 27N44W 
23N47W. SCATTERED SHOWERS ARE WITHIN 70 NM E OF THE TROUGH N OF 
27N. A THIRD SURFACE TROUGH EXTENDS S FROM THE LOW CENTER TO 
NEAR 28N50W GENERATING SCATTERED SHOWERS WITHIN 90 NM E OF THE 
TROUGH. SURFACE RIDGING DOMINATES THE REST OF THE E ATLC 
ANCHORED BY A 1019 MB HIGH NEAR 32N30W.

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

$$

GARCIA