[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251141
TWDAT

16TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER
MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU NEAR
12N16W TO 7N20W. THE ITCZ BEGINS AT 7N20W AND CONTINUES ALONG
7N33W 2N50W 2N57W. SCATTERED MODERATE/STRONG CONVECTION IS FROM
4N-8N BETWEEN 20W-37W. ISOLATED MODERATE/STRONG CONVECTION IS
FROM EQ-6N BETWEEN 42W-48W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-9N BETWEEN 48W-57W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING SPREADS OVER THE GULF OF MEXICO TONIGHT WITH
AXIS NEAR 93W SUPPORTING SURFACE RIDGING EXTENDING FROM A HIGH
CEN  TER 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 SCATTERED SHOWERS/THUNDERSTORMS ALONG
THE EASTERN MEXICO COAST FROM 21N-26N BETWEEN 96W-100W. ISOLATED
SHOWERS ARE ALSO IN THE BAY OF CAMPECHE NEAR A SURFACE TROUGH
ALONG 20N93W TO 16N91W. 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 IN THE SW GULF. SURFACE RIDGING WILL DOMINATE THE AREA
THROUGHOUT THE WEEKEND.

CARIBBEAN SEA...
CLEAR SKIES SPREAD ACROSS A LARGE AREA OF THE CARIBBEAN
INCLUDING THE NW AND SE CORNERS. HOWEVER...A COUPLE AREAS OF
SHOWERS/THUNDERSTORMS ARE STILL PRESENT. THE FIRST AREA IS IN
THE SW CARIBBEAN WHERE SCATTERED SHOWERS/THUNDERSTORMS ARE FROM
9N-14N BETWEEN 78W-84W. THIS IS LIKELY INFLUENCED BY THE MONSOON
TROUGH WHICH EXTENDS THROUGH COSTA RICA AND PANAMA TO NORTHERN
COLOMBIA. 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 68W. 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...
NO SHOWER ACTIVITY IS ACROSS HISPANIOLA AT THIS TIME. 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 73W SUPPORTS A COLD FRONT ALONG
32N72W 29N76W 28N80W. A SURFACE TROUGH IS TO THE EAST ALONG
32N71W TO 24N76W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
EXTEND UP TO 230 NM EAST OF THE TROUGH AXIS TO THE NORTH OF 26N.
AN UPPER LEVEL RIDGE DOMINATES THE CENTRAL ATLC ALONG 50W
SUPPORTING BROAD SURFACE RIDGING ACROSS THIS AREA. AN UPPER
LEVEL LOW NEAR 31N34W SUPPORTS A WEAK 1022 MB SURFACE LOW NEAR
30N38W WITH A SURFACE TROUGH EXTENDING FROM THE LOW CENTER ALONG
28N36W 22N44W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE AXIS WITH
AN AREA OF SCATTERED SHOWERS TO THE EAST FROM 26N-31N BETWEEN
31W-36W. 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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