[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 222353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUL 22 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 2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM CINDY IS CENTERED NEAR 46.9N 34.3W AS OF 2100 UTC
MOVING NE AT 24 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003
MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT.
PUBLIC ADVISORIES ON CINDY ARE ISSUED UNDER WMO HEADER WTNT33
KNHC AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES ARE
ISSUED UNDER WMO HEADER WTNT23 KNHC AND UNDER AWIPS HEADER
MIATCMAT3.

AN ACTIVE TROPICAL WAVE IS APPROACHING THE WINDWARD ISLANDS
ALONG 18N55W TO 11N57W MOVING W TO WNW NEAR 15 KT. SATELLITE
IMAGERY INDICATES BROAD CYCLONIC FLOW IS AROUND THE WAVE AXIS.
TOTAL PRECIPITABLE WATER IMAGERY ALSO SHOWS A SURGE OF DEEP
LAYER MOISTURE IS MAINLY W OF THE AXIS. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 12N-15N BETWEEN 56W-61W...AND
FROM 17N-19N BETWEEN 60W-67W IMPACTING THE VIRGIN ISLANDS AND
PUERTO RICO. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 14N-20N BETWEEN 54W-60W. THIS WAVE WILL CONTINUE TO BRING
ACTIVE WEATHER...SOMETIMES STRONG...TO THE LESSER ANTILLES OVER
THE NEXT DAY OR SO WITH SOME SLOW DEVELOPMENT POSSIBLE.

...TROPICAL WAVES...

TROPICAL WAVE IN THE ERN TRPCL ATLC EXTENDS ALONG 15N28W TO
7N33W MOVING W AT 10-15 KT. SATELLITE IMAGERY AND SATELLITE
DERIVED WINDS INDICATE BROAD CYCLONIC FLOW IS AROUND THE WAVE
AXIS. A SLIGHT RIDGE OF MOISTURE WITH ENHANCED VALUES IS EVIDENT
IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 10N-14N BETWEEN 29W-33W.

TROPICAL WAVE IS E OF THE WINDWARD ISLANDS. SEE SPECIAL FEATURE
SECTION ABOVE FOR MORE DETAILS.

TROPICAL WAVE EXTENDS ACROSS THE YUCATAN PENINSULA ALONG 22N87W
TO 16N91W MOVING W 15-20 KT. THE WAVE IS EMBEDDED WITHIN
MODERATE MOISTURE ACROSS THE YUCATAN AND NW CARIBBEAN. SCATTERED
MODERATE/STRONG CONVECTION IS WITHIN 60 NM OF THE WAVE AXIS. A
CLUSTER OF SIMILAR ACTIVITY IS ALSO E OF THE AXIS FROM 19N-21N
BETWEEN 84W-86W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 15N ALONG 15N10W 10N18W TO 11N23W. THE ITCZ CONTINUES FROM
11N23W ALONG 13N29W 7N41W 9N50W. A CLUSTER OF NUMEROUS STRONG
CONVECTION IS MOVING OFF THE W COAST OF AFRICA FROM 7N-12N
BETWEEN 13W-17W. ISOLATED MODERATE CONVECTION IS WITHIN  90 NM N
AND 150 NM S OF THE AXIS BETWEEN 34W-52W.

...DISCUSSION...

GULF OF MEXICO...
MUCH OF THE WRN GULF OF MEXICO IS UNDER FAIR WEATHER THIS
EVENING DUE TO THE COMBINATION OF WEAK SURFACE RIDGING AROUND A
1016 MB HIGH OVER MEXICO NEAR 21N99W AND DRY AIR ALOFT AROUND AN
UPPER LEVEL LOW CENTERED OVER THE BAY OF CAMPECHE NEAR 21N95W. A
TROPICAL WAVE OVER THE YUCATAN PENINSULA IS BRINGING MOISTURE
FROM THE NW CARIBBEAN OVER THE PENINSULA. THE WAVE IS ALSO UNDER
THE DIFFLUENT SIDE OF THE UPPER LEVEL LOW. THIS COMBINATION IS
ENHANCING SHOWERS/THUNDERSTORMS ACROSS THE YUCATAN FROM 16N-22N
BETWEEN 88W-91W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES
ENHANCED MOISTURE VALUES ARE ACROSS THE ERN GULF OF MEXICO.
WHILE WEAK SURFACE RIDGING IS ACROSS THIS AREA ALONG WITH UPPER
RIDGING CENTERED OVER WRN TENNESSEE...ISOLATED
SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF THE ERN GULF E OF 90W.
STRONG AND MORE WIDESPREAD SHOWERS/THUNDERSTORMS ARE ACROSS
CENTRAL AND N FLORIDA. WEAK SURFACE RIDGING IS EXPECTED TO
REMAIN ACROSS THE BASIN...AS WELL AS MOISTURE ACROSS THE ERN
GULF. SHOWER ACTIVITY MAY INCREASE OVER THE BAY OF CAMPECHE AS
THE TROPICAL WAVE CURRENTLY OVER THE YUCATAN PENINSULA MOVES
WWD.

CARIBBEAN SEA...
MODERATE MOISTURE REMAINS OVER THE NW CARIBBEAN IN THE WAVE OF A
TROPICAL WAVE NOW ACROSS THE YUCATAN PENINSULA BRINGING CLUSTERS
OF SHOWERS/THUNDERSTORMS ACROSS THE AREA. A LARGE CLUSTER IS
FROM 19N-21N BETWEEN 84W-86W. MORE WIDESPREAD ACTIVITY IS ACROSS
MUCH OF CUBA...AND HAITI. STRONG SHOWERS/THUNDERSTORMS ARE
ACROSS MUCH OF CENTRAL AMERICA INCLUDING
PANAMA...NICARAGUA...HONDURAS...AND GUATEMALA. SOME OF THIS
ACTIVITY IS INFLUENCED BY THE MONSOON TROUGH EXTENDING FROM THE
E PACIFIC ACROSS COSTA RICA TO NRN COLOMBIA. ALOFT...AN UPPER
LEVEL TROUGH COVERS THE WRN CARIBBEAN CENTERED NEAR 21N80W. WSW
FLOW COVERS THE CENTRAL AND ERN CARIBBEAN WITH SIGNIFICANT DRY
AIR ALOFT ACROSS THE CENTRAL CARIBBEAN. THIS DRY AIR IS
MAINTAINING MOSTLY FAIR WEATHER ACROSS THIS PORTION OF THE
BASIN. MOISTURE ASSOCIATED WITH A TROPICAL WAVE E OF THE
WINDWARD ISLANDS IS ALREADY IMPACTING THE ERN CARIBBEAN BRINGING
SCATTERED SHOWERS/THUNDERSTORMS TO THE ISLANDS N OF 13N
EXTENDING WWD TO PUERTO RICO. EXPECT THIS ACTIVITY TO CONTINUE
AS THE WAVE MOVES WWD. SHOWERS/THUNDERSTORMS WILL ALSO LIKELY
BEGIN ACROSS HISPANIOLA AS THE HIGH MOISTURE VALUES AND
CURRENTLY MOVING OVER THE WINDWARD PASSAGE.

ATLANTIC OCEAN...
BROAD SURFACE RIDGING COVERS THE MAJORITY OF THE ATLC ANCHORED
BY A 1029 MB AZORES HIGH NEAR 40N30W PROVIDING MOSTLY FAIR
WEATHER BASIN-WIDE. SCATTERED SHOWERS/THUNDERSTORMS ARE NOTED
ACROSS THE NW BAHAMAS. ISOLATED SHOWERS ARE ALSO FROM 26N-30N
BETWEEN 65W-75W ASSOCIATED WITH AN UPPER LEVEL LOW NEAR 30N69W.
SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO N AND E OF THE LESSER
ANTILLES ASSOCIATED WITH A TROPICAL WAVE. ACTIVITY IS S OF 24N
BETWEEN 54W-68W. ALOFT...AN UPPER LEVEL RIDGE IS CENTERED NEAR
20N48W WITH AXIS EXTENDING TO THE NE. AN UPPER LEVEL TROUGH
EXTENDS FROM THE AZORES ISLANDS TO NEAR 16N39W. AN UPPER LEVEL
RIDGE COVERS THE FAR ERN ATLC CENTERED S OF THE CANARY ISLANDS
NEAR 23N19W.


EVEN THOUGH TROPICAL STORM BRET IS N OF THE DISCUSSION
AREA...SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE SYSTEM ARE
IMPACTING THE AREA N OF 26N BETWEEN 64W-72W. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE NW BAHAMAS. THE
REMAINDER OF THE BASIN IS DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED AROUND A 1032 MB AZORES HIGH NEAR 39N32W PROVIDING FAIR
WEATHER BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE EXTENDS OVER
THE FAR WRN ATLC FROM THE ERN CONUS. AN UPPER LEVEL TROUGH IS TO
THE E N OF 29N. AN UPPER LEVEL RIDGE EXTENDS FROM NEAR 46N36W TO
AN ANTI-CYCLONIC CENTER NEAR 21N49W. AN UPPER TROUGH EXTENDS
FROM THE AZORES ISLANDS TO NEAR 24N38W. A SECOND ANTI-CYCLONIC
CENTER IS JUST N OF THE CAPE VERDE ISLANDS NEAR 21N26W...WHILE
ANOTHER UPPER LEVEL TROUGH COVERS THE FAR E ATLC EXTENDING FROM
PORTUGAL TO THE CANARY ISLANDS.

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

$$
WALTON





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