[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250542
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAY 25 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 10N14W
TO 8N19W. THE ITCZ BEGINS AT 8N19W AND CONTINUES ALONG 6N35W
6N48W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-6N
BETWEEN 19W-23W...AND FROM 3N-7N BETWEEN 25W-36W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN 43W-
45W...EQ-2N BETWEEN 41W-46W...AND FROM 3N-6N BETWEEN 48W-52W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING SPREADS OVER THE GULF OF MEXICO TONIGHT WITH
AXIS NEAR 94W SUPPORTING SURFACE RIDGING EXTENDING FROM A HIGH
CENTER OVER THE GREAT LAKES REGION. DRY AIR ALOFT COVERS A GOOD
PORTION OF THE BASIN PROVIDING FAIR CONDITIONS AND CLEAR SKIES.
DIFFLUENT FLOW ALOFT AROUND THE WEST SIDE OF THE UPPER RIDGE
CONTINUES TO PRODUCE A LARGE AREA OF SHOWERS/THUNDERSTORMS OVER
NE MEXICO NEAR A SQUALL LINE FROM 26N98W TO 24N101W...AS OF 0300
UTC. LIGHT NE WINDS OF 5-10 KT SPREAD ACROSS THE EASTERN GULF
BECOMING EASTERLY ACROSS THE CENTRAL AND WESTERN PORTIONS AND
REACHING 15 KT. A FEW 20 KT WINDS ARE POSSIBLE ALONG THE WEST
COAST OF THE YUCATAN PENINSULA. A FEW SHOWERS/THUNDERSTORMS ARE
STILL ACROSS SOUTHERN MEXICO AS WELL FROM 17N-19N BETWEEN 91W-
95W. SURFACE RIDGING WILL DOMINATE THE AREA THROUGHOUT THE
WEEKEND.

CARIBBEAN SEA...
MUCH OF THE LATER AFTERNOON CONVECTION HAS DIED DOWN NOW.
HOWEVER...SEVERAL AREAS OF SHOWERS/THUNDERSTORMS ARE STILL
PRESENT. THE FIRST AREA IS OFF THE COAST OF NICARAGUA WHERE
SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 11N-15N BETWEEN 78W-
83W. THIS AREA LIES NEAR THE BASE OF A BROAD UPPER LEVEL TROUGH
ACROSS THE AREA. IT ALSO COINCIDES WITH AN AREA OF MAXIMUM
MOISTURE IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO OVER THE NE CARIBBEAN
FROM 16N-19N EAST OF 66W. THIS ACTIVITY IS ALSO WITHIN AN AREA
OF ENHANCED MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER
IMAGERY. THE REMAINDER OF THE AREA HAS MOSTLY CLEAR SKIES WITH
ONLY A FEW LOW-LEVEL ISOLATED SHOWERS MOVING WITHIN TRADEWIND
FLOW OF 15-20 KT. LITTLE CHANGE IS EXPECTED ACROSS THE BASIN.
MOISTURE IS EXPECTED TO REMAIN OVER THE SW CARIBBEAN AS WELL AS
THE NE CORNER. A SURFACE TROUGH/FRONTAL BOUNDARY IN THE WEST
ATLC WILL MOVE EASTWARD JUST NORTH OF THE BASIN AND MAY
INFLUENCE SHOWERS/THUNDERSTORMS ACROSS THE NORTHERN ISLANDS.

HISPANIOLA...
DEEP CONVECTION FROM AFTERNOON HEATING AND INSTABILITY HAS NOW
DIED DOWN WITH ONLY POSSIBLE LOW-LEVEL ISOLATED SHOWERS
REMAINING. WATER VAPOR IMAGERY INDICATES MODERATE MOISTURE
ALOFT...AND TOTAL PRECIPITABLE WATER IMAGERY INDICATES A SIMILAR
SCENARIO WITH HIGHER MOISTURE JUST TO THE EAST. MODEL GUIDANCE
INDICATES THAT THIS AREA OF HIGHER MOISTURE TO THE EAST WILL
DRIFT WEST TOWARDS THE ISLAND...WHICH COINCIDES WITH SURFACE
TROUGHING TO THE NORTH. THIS COMBINATION MAY LEAD TO A GREATER
CHANCE OF SHOWERS/THUNDERSTORMS BY THE END OF THE WEEKEND.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH ALONG 75W SUPPORTS A FRONTAL BOUNDARY JUST
NORTH OF THE DISCUSSION AREA ALONG WITH A SURFACE TROUGH TO THE
EAST ALONG 32N72W TO 85N79W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS EXTEND UP TO 230 NM EAST...75 NM WEST OF THE AXIS
TO THE NORTH OF 29N. AN UPPER LEVEL RIDGE DOMINATES THE CENTRAL
ATLC ALONG 50W SUPPORTING BROAD SURFACE RIDGING ACROSS THIS
AREA. AN UPPER LEVEL LOW NEAR 31N35W SUPPORTS A DISSIPATING
STATIONARY FRONT THAT ENTERS THE AREA NEAR 31N37W AND CONTINUES
ALONG 28N35W 22N45W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE
AXIS WITH AN AREA OF SCATTERED SHOWERS TO THE EAST FROM 28N-32N
BETWEEN 29W-34W. THE REMAINDER OF THE BASIN IS ALSO INFLUENCED
BY SURFACE RIDGING SUPPORTED BY BROAD UPPER RIDGING ACROSS WEST
AFRICA. BROAD UPPER RIDGING ALSO COVERS THE TROPICAL ATLC.

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

$$
WALTON

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