[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070157 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAY 06 2011

...CORRECTED FOR ISSUANCE TIME...

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2230 UTC.

...ITCZ...

ITCZ AXIS EXTENDS FROM MAURITANIA NEAR 11N12W ALONG 5N20W 1N30W
CROSSING THE EQUATOR NEAR 35W AND CONTINUING INTO NE BRAZIL NEAR
1S54W. ISOLATED MODERATE/STRONG CONVECTION IS WITHIN 90 NM S OF
THE AXIS BETWEEN 16W-26W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 120 N M N...AND 160 NM S OF THE AXIS W OF
26W.

...DISCUSSION...

GULF OF MEXICO...
WHILE MOSTLY ZONAL WLY FLOW ALOFT COVERS THE GULF OF
MEXICO...WATER VAPOR IMAGERY CONTINUES TO INDICATE A MID-UPPER
LEVEL SHORTWAVE TROUGH THAT IS NOW MOVING OVER NE FLORIDA AND
INTO THE FAR W ATLC. THE SHORTWAVE SUPPORTS A FORMING COLD FRONT
LOCATED FROM NEAR JACKSONVILLE FL TO TAMPA CONTINUING INTO THE
CENTRAL GULF NEAR 25N90W WHERE IT CONTINUES AS A SURFACE TROUGH
TO THE BAY OF CAMPECHE ALONG 23N92W 19N91W...AS OF 2100 UTC.
POSSIBLE ISOLATED SHOWERS ARE ALONG THE BOUNDARY OVER LAND AND
WITHIN 45 NM EITHER SIDE OF THE BOUNDARY OVER WATER. A SECOND
SURFACE TROUGH IS AHEAD OF THE FRONT EXTENDING ACROSS THE
FLORIDA PENINSULA OVER LAKE OCKEECHOBEE FROM 27N80W TO 26N84W. A
LINE OF STRONG SHOWERS IS S OF THIS BOUNDARY WITHIN 50 NM.
SURFACE RIDGING IS BUILDING IN BEHIND THE FRONTAL BOUNDARY
AROUND A 1018 MB HIGH CENTERED S OF CENTRAL LOUISIANA NEAR
29N92W. THE SURFACE RIDGE COMBINED WITH DRY AIR ALOFT IS
PROVIDING FAIR WEATHER ACROSS THE NRN GULF. THE FRONTAL SYSTEM
IS EXPECTED TO MOVE OUT OF THE AREA BY SATURDAY AFTERNOON AS
SURFACE RIDGING BUILDS IN ITS WAKE.

CARIBBEAN SEA...
MUCH OF THE NW CARIBBEAN IS UNDER THE INFLUENCE OF AN UPPER
LEVEL ANTICYCLONE CENTERED NEAR 18N81W ALONG WITH DRY AIR AND
SUBSIDENCE SUPPORTING FAIR SURFACE CONDITIONS. HOWEVER...A STRIP
OF ENHANCED MOISTURE LIES OVER THE SRN CARIBBEAN SUPPORTING
AREAS OF SHOWER ACTIVITY. SCATTERED SHOWERS ARE NOTED ACROSS SRN
HISPANIOLA TO JAMAICA. STRONGER SHOWERS/POSSIBLE THUNDERSTORMS
ARE ACROSS PANAMA...COSTA RICA...AND THE COASTAL WATERS S OF 12N
BETWEEN 79W-86W. ACROSS THE ERN CARIBBEAN...A SECOND UPPER LEVEL
RIDGE SITS OVER THE AREA EXTENDING FROM AN UPPER LEVEL
ANTICYCLONE N OF BRAZIL NEAR 6N42W. AT THE SURFACE...A SHEAR
AXIS EXTENDS FROM THE ATLC ACROSS THE WINDWARD ISLANDS ALONG
15N61W TO 12N67W SUPPORTING SCATTERED SHOWERS WITHIN 100 NM
EITHER SIDE OF THE AXIS. 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...
POSSIBLE ISOLATED SHOWERS ARE WITHIN 100 NM OFF THE NE FLORIDA
COASTLINE AHEAD OF A FORMING FRONTAL BOUNDARY MOVING ACROSS THE
PENINSULA. AN UPPER LEVEL SHORTWAVE TROUGH SUPPORTS THE FRONT
AND IS BEGINNING TO MOVE OVER THE W ATLC. A BROAD UPPER LEVEL
RIDGE IS TO THE E BETWEEN 55W-75W SUPPORTING A 1023 MB HIGH NEAR
34N71W. AN OCCLUDED LOW PRESSURE SYSTEM IS IMPACTING THE CENTRAL
ATLC WITH AN UPPER LEVEL LOW CENTERED NEAR 33N48W AND THE LOW
LEVEL CENTER NEAR 33N50W.  A SERIES OF PERTURBATIONS ARE
ASSOCIATED WITH THE SYSTEM. THE OUTERMOST SURFACE TROUGH IS
ALONG 30N41W 24N44W 17N50W CONTINUING AS A SHEAR LINE TO THE
WINDWARD ISLANDS NEAR 15N61W. A SECOND SURFACE TROUGH EXTENDS
ALONG 30N48W 25N50W 22N56W. A LARGE AREA OF SCATTERED SHOWERS IS
E OF THE OUTERMOST TROUGH N OF 21N BETWEEN 33W-42W. SCATTERED
SHOWERS ARE ALSO WITHIN 150 NM E OF THE INNER TROUGH. AN UPPER
LEVEL RIDGE COVER THE ERN ATLC BETWEEN 22W-38W SUPPORTING A 1021
MB HIGH NEAR 27N31W. A NARROW UPPER LEVEL TROUGH EXTENDS DOWN
11W SUPPORTING A WEAK FRONTAL SYSTEM JUST W OF THE CANARY
ISLANDS ALONG 32N14W 28N23W.

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

$$
WALTON






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