[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM BRET AT 21/1500 UTC WAS NEAR 33.8N
70.6W. BRET IS MOVING NORTHEASTWARD AT 08 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 35 KT WITH GUSTS TO 45 KT. PUBLIC ADVISORIES ON BRET
ARE ISSUED UNDER WMO HEADER WTNT32 KNHC AND UNDER AWIPS HEADER
MIATCPAT2. FORECAST/ ADVISORIES ARE ISSUED UNDER WMO HEADER
WTNT22 KNHC AND UNDER AWIPS HEADER MIATCMAT2. SCATTERED HEAVY
SHOWERS AND THUNDERSTORMS ARE FROM 26N TO 34N BETWEEN 68W-72W.

THE CENTER OF TROPICAL STORM CINDY AT 21/1500 UTC WAS NEAR 40.3N
47.3W. CINDY IS MOVING NORTHEASTWARD 25 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1002 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 50 KT WITH GUSTS TO 60 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. SCATTERED MODERATE
TO STRONG RAINSHOWERS AND THUNDERSTORMS ARE WITHIN 90-150 NM
AROUND THE CENTER.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE EASTERN TROPICAL ATLC S OF CAPE VERDE
ISLANDS ANALYZED FROM 12N23W TO 5N26W...MOVING W AT 15-20 KT.
THIS WAVE IS EMBEDDED WITHIN A REGION OF ELEVATED VALUES OF
MOISTURE ON TOTAL PRECIPITABLE WATER PRODUCT. LOW LEVEL CLOUD
CYCLONIC TURNING IS VERY WELL OBSERVED ON VISIBLE SATELLITE
IMAGERY...AS WELL AS AN EARLIER ASCAT PASS AND LOW LEVEL
SATELLITE DERIVED WINDS. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS FROM 4N-12N BETWEEN 22W-30W. THIS AREA OF
CONVECTION IS ALSO RELATED TO THE ITCZ.

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLC WITH AXIS
ANALYZED FROM 16N47W TO 6N50W MOVING W AT 15-20 KT. THIS WAVE
MOVES ALONG THE LEADING EDGE OF A DEEP MOISTURE SURGE ON TPW.
LOW LEVEL CLOUD CYCLONIC TURNING IS VERY CLEAR ON VISIBLE
SATELLITE IMAGERY AND DERIVED WINDS. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS WITHIN 200 NM W OF THE AXIS N OF
11N.

A TROPICAL WAVE IS MOVING ACROSS THE NW CARIBBEAN WITH AXIS
ANALYZED FROM NEAR 23N80W TO 18N81W. THE MOISTURE ASSOCIATED TO
THIS WAVE IS LIMITED AND ASSOCIATED TO AN UPPER LEVEL CYCLONIC
CIRCULATION CENTERED IN THE WINDWARD PASSAGE. CYCLONIC TURNING
IS VERY SUBTLE AROUND THE WAVE AXIS. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE WITHIN 90 NM ON EITHER SIDE OF ITS
AXIS.

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

THE MONSOON TROUGH EXTENDS OVER AFRICA AND BRIEFLY ENTERS THE
ATLC OCEAN FROM THE COAST OF SENEGAL NEAR 15N17W TO 12N20W. THE
ITCZ CONTINUES W OF A TROPICAL WAVE FROM 7N29W TO 8N42W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN
100/150 NM ON EITHER SIDE OF THE ITCZ AXIS. THIS AREA OF
CONVECTION IS ALSO CONFINED TO THE TROPICAL WAVE MENTIONED
ABOVE.

...DISCUSSION...

GULF OF MEXICO...
THE UPPER LEVELS OF THE ATMOSPHERE ACROSS THE GULF ARE
RELATIVELY DRY WITH MODERATE SUBSIDENCE NOTICED ON WATER VAPOR
IMAGERY. AT SURFACE...THE PRESSURE GRADIENT IS COMPARATIVELY
FLAT GENERATING A WEAK ANTICYCLONIC FLOW OBSERVED ACROSS THE
AREA...WITH LOW TOP ISOLATED SHOWERS EMBEDDED IN THE FLOW N OF
26N E OF 93W. SOME OF THESE SHOWERS MAY BECOME STRONG THROUGHOUT
THE LATE AFTERNOON HOURS...ESPECIALLY THOSE CLOSE TO THE COASTAL
WATERS OF LOUISIANA. NO SIGNIFICANT DEEP CONVECTIVE PRECIP IS
FOUND ELSEWHERE ACROSS THE BASIN. A TROPICAL WAVE CURRENTLY
MOVING ACROSS THE NW CARIBBEAN BASIN WILL ENTER THE FAR SE GULF
IN THE NEXT 6-12 HOURS...BRINGING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS TO THE FLORIDA STRAITS E OF 83W.

CARIBBEAN SEA...
A TROPICAL WAVE IS MOVING ACROSS THE NW BASIN ANALYZED FROM NEAR
23N80W TO 18N81W GENERATING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITHIN 90 NM ON EITHER SIDE OF ITS AXIS. THIS WAVE
IS ALSO INTERACTING WITH AN UPPER LEVEL CYCLONIC CIRCULATION
CENTERED IN THE WINDWARD PASSAGE. THE WAVE WILL CONTINUE TO
TRACK WNW WITH LIMITED ACTIVITY DURING THE NEXT 24 HOURS.
SIMILAR CONVECTION IS FOUND IN THE FAR SW BASIN...WITHIN 70 NM
OFF THE COAST OF COLOMBIA...PANAMA...AND COSTA RICA...DUE TO
CLOSE PROXIMITY TO THE MONSOON TROUGH ANALYZED ACROSS CENTRAL
AMERICA INTO NORTHERN COLOMBIA. FAIR WEATHER CONDITIONS ARE
OBSERVED ACROSS THE REMAINDER OF THE CARIBBEAN...WITH EASTERLY
TRADE WINDS RANGING FROM 10-20 KT. THE MONSOON TROUGH IS
EXPECTED TO LIFT N WITHIN THE NEXT 24-36 HOURS WITH CONVECTION
EXPANDING ACROSS THE SW BASIN AND INLAND PORTIONS OF CENTRAL
AMERICA REACHING TO NORTHERN NICARAGUA. IN THE MEAN TIME...A
TROPICAL WAVE CURRENTLY IN THE CENTRAL TROPICAL ATLC WILL BEGIN
TO AFFECT THE LESSER ANTILLES IN THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SCATTERED HEAVY SHOWERS AND THUNDERSTORMS EXTEND INTO OUR
DISCUSSION AREA S OF TROPICAL STORM BRET FROM 26N TO 34N BETWEEN
68W-72W. THIS AREA OF CONVECTION IS EXPECTED TO MOVE NE OUT OF
OUR AREA OVER THE NEXT 24 HOURS. A BROAD SURFACE RIDGE DOMINATED
THE REMAINDER OF THE ATLC N OF 17N...ANCHORED BY A 1034 MB HIGH
W OF THE AZORES NEAR 39N32W...LEAVING THE REMAINDER OF THE
DISCUSSION AREA WITH FAIR WEATHER THIS AFTERNOON.

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

$$

GARCIA


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