[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAY 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0430 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED FROM SIERRA LEONE NEAR 7N12W ALONG 3N20W
1N30W 2N40W AND INTO NRN BRAZIL NEAR 1S48W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM S OF THE
AXIS BETWEEN 11W-16W. SCATTERED MODERATE/STRONG CONVECTION FROM
3N-5N BETWEEN 21W-30W...AND FROM 2N-6N BETWEEN 40-44W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH COVERS THE ERN GULF OF MEXICO WITH AXIS
EXTENDING DOWN THE FLORIDA PENINSULA. THE UPPER TROUGH SUPPORTED
A COLD FRONT THAT EXTENDS FROM NE FLORIDA NEAR JACKSONVILLE
CONTINUING SW ALONG 26N86W 23N92W 23N97W...AS OF 0300 UTC. RADAR
IMAGERY INDICATES A LINE OF STRONG SHOWERS/THUNDERSTORMS WITHIN
60 NM AHEAD OF THE FRONT N OF 27N. STRONG DRY AIR AND SUBSIDENCE
COVER THE BASIN BEHIND THE UPPER TROUGH SUPPRESSING CONVECTION
AND SUPPORTING FAIR WEATHER ACROSS THE REMAINDER OF THE AREA. A
FEW ISOLATED SHOWERS ARE NOTED OFF THE ERN COAST OF MEXICO NEAR
24N98W AS STORMS INLAND HAVE MOVED EWD OVER WATER. EXPECT THE
FRONT TO DRIFT EWD AND DISSIPATE AS A SECONDARY FRONT MOVES IN
BEHIND IT MONDAY AND TUESDAY. THIS SETUP WILL PROVIDE MOIST
CONDITIONS ACROSS MUCH OF THE ERN GULF OF MEXICO.

CARIBBEAN SEA...
BROAD UPPER TROUGHING SITS ACROSS THE ENTIRE CARIBBEAN EXTENDING
FROM AN UPPER LEVEL LOW OVER THE UPPER MISSISSIPPI VALLEY. WATER
VAPOR IMAGERY INDICATES MOSTLY DRY AIR ACROSS THE NW CARIBBEAN
WITH MOISTER CONDITIONS S OF 13N AND E OF 67W. THIS PATTERN IS
PROVIDING FAIR CONDITIONS ACROSS THE ENTIRE NW PORTION OF THE
BASIN. A SURFACE TROUGH EXTENDS ACROSS THE ERN CARIBBEAN FROM
NEAR SRN DOMINICAN REPUBLIC TO THE SW CARIBBEAN ALONG 19N69W
12N73W 9N82W. TOTAL PRECIPITABLE WATER IMAGERY SHOWS ENHANCED
MOISTURE VALUES E AND S OF THE TROUGH AXIS WHERE SCATTERED
SHOWERS/THUNDERSTORMS COVER THE AREA. SOME OF THIS ACTIVITY IS
INFLUENCED BY UPPER LEVEL DIFFLUENCE AROUND THE ERN SIDE OF THE
UPPER TROUGH. EXPECT SURFACE TROUGHING TO REMAIN ACROSS THE ERN
CARIBBEAN WITH ENHANCED MOISTURE LEVELS SUPPORTING CONVECTION.

ATLANTIC OCEAN...
UPPER LEVEL DIFFLUENCE AROUND AN UPPER LEVEL TROUGH WITH AXIS
DOWN THE FLORIDA PENINSULA IS SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS N OF 26N BETWEEN 75W-80W. THE REMAINDER OF
THE W ATLC IS EXPERIENCING FAIR CONDITIONS UNDER THE INFLUENCE
OF DRY AIR ALOFT AND SURFACE RIDGING AROUND A 1014 MB HIGH NEAR
28N73W. HOWEVER...FARTHER E ANOTHER LOW PRESSURE SYSTEM IS
IMPACTING THE CENTRAL ATLC. AN UPPER LEVEL TROUGH IS ALONG 54W
SUPPORTING A 1006 MB LOW NEAR 35N59W. A SURFACE TROUGH EXTENDS
SWD FROM THE LOW CENTER TO NEAR 26N61W DEPICTING THE MAIN WIND
SHIFT. THE ACTIVE WEATHER IS FARTHER E ASSOCIATED WITH UPPER
LEVEL DIFFLUENCE. SCATTERED SHOWERS/THUNDERSTORMS ARE BETWEEN
45W-51W N OF 23N...AND BETWEEN 50W-67W S OF 23N. THE ERN ATLC IS
EXPERIENCING GENERALLY FAIR WEATHER UNDER AN UPPER LEVEL RIDGE
ALONG 38W SUPPORTING A SURFACE RIDGE ALONG 35W. AN UPPER LEVEL
LOW CONTINUES TO SPIN NE OF THE CANARY ISLANDS NEAR 34N20W
SUPPORTING A PAIR OF 1012 MB LOWS NEAR 30N18W AND 32N12W.
MINIMAL ACTIVE WEATHER IS ASSOCIATED WITH EITHER LOW IN THE
DISCUSSION AREA. EXPECT MOIST CONDITIONS TO REMAIN ACROSS THE
CENTRAL ATLC WITH ACTIVITY INCREASING OVER THE W ATLC AS A COLD
FRONT OVER THE GULF OF MEXICO PROGRESSES EWD INTO THE W ATLC.

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

$$
WALTON





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