[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 221145
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN AUG 22 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIX IS CENTERED NEAR 12.1N 33.4W AT 22/0900
UTC...OR LOCATED ABOUT 600 MILES WEST-SOUTHWEST OF THE
SOUTHERNMOST CAPE VERDE ISLANDS MOVING W-NW AT 08 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND
SPEED IS 30 KT WITH GUSTS TO 40 KT. STRENGTHENING IS FORECAST
OVER THE NEXT FEW DAYS AS THE CYCLONE REMAINS OVER WARM SEA
SURFACE TEMPERATURES AND WITHIN A RELATIVELY LOW NORTHEASTERLY
SHEAR ENVIRONMENT. THIS IS EXPECTED TO PROVIDE AN OVERALL
FAVORABLE UPPER LEVEL DIFFLUENT ENVIRONMENT FOR THE SYSTEM TO
MAINTAIN ORGANIZED CONVECTION AND PROVIDE FOR MINIMAL WIND
SHEAR. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM
10N-15N BETWEEN 34W-39W. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 11N49W TO 17N52W TO 24N51W MOVING W
AT 15-20 KT. WEAK CYCLONIC FLOW IS NOTED IN THE LOW-LEVEL CLOUD
FIELD ALONG THE WAVE AXIS. THIS SYSTEM MOVES ALONG WITH AN AREA
OF MODERATE VALUES OF DEEP LAYER MOISTURE OBSERVED ON THE TPW
IMAGERY. HOWEVER...MUCH OF THE MOISTURE TO THE EAST OF THE WAVE
IS POSITIONED BENEATH A STABLE SAHARAN AIR LAYER THAT COVERS
MUCH OF THE CENTRAL ATLC. HOWEVER...SCATTERED SHOWERS ARE WITHIN
40 NM ON EITHER SIDE OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 18N69W TO 26N67W MOVING WNW AT 15-20
KT. THE WAVE COINCIDES WITH A MID-LEVEL TROUGH OVER THE W ATLC
BETWEEN 65W-74W. MAXIMUM TOTAL PRECIPITABLE WATER VALUES ARE
HIGHEST N OF 20N BETWEEN 61W-69W AS THIS MOISTURE CONTINUES TO
ADVECT NORTHWARD DUE TO A WEAKNESS IN THE SUBTROPICAL RIDGE
BETWEEN 70W-80W. ISOLATED MODERATE CONVECTION AND WIDELY
SCATTERED SHOWERS ARE OCCURRING FROM 20N-29N BETWEEN 62W-70W.

...ITCZ...

ITCZ AXIS IS ANALYZED FROM THE WEST COAST OF AFRICA OVER SIERRA
LEONE NEAR 8N13W TO 10N20W. THEN RESUMES OVER NEAR 8N39W 10N49W
8N55W AND CONTINUES OVER NORTHERN SOUTH AMERICA. THE GRADUAL
DISSIPATION OF THE MONSOON TROUGH THAT HAS PERSISTED OVER THE
PAST SEVERAL DAYS OVER THE TROPICAL EASTERN ATLC...IS ANALYZED
AS A SURFACE TROUGH FROM NE OF T.D. SIX NEAR 14N30W TO 17N21W.
HOWEVER...MOST OF THE CONVECTION IS ASSOCIATED TO T.D. SIX. A
BROAD AREA OF SCATTERED MODERATE TO STRONG CONVECTION IS MOVING
OFF THE WESTERN AFRICA COAST E OF 24W FROM 6N-15N.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION COVERS THE BASIN.
THIS UPPER LEVEL FEATURE IS PROVIDING A DRY EASTERLY FLOW ALOFT
OVER MUCH OF THE GULF. LOW TO MID-LEVEL INSTABILITY AND UPPER
LEVEL DIFFLUENCE PROVIDED BY THE UPPER LEVEL RIDGE IS GENERATING
SCATTERED SHOWERS AND TSTMS OVER THE EASTERN GULF E OF
88W...INCLUDING THE FLORIDA PENINSULA AND FLORIDA STRAITS.
SCATTERED SHOWERS AND THUNDERSTORMS ARE ALSO OVER THE BAY OF
CAMPECHE S OF 20N. THIS ACTIVITY IS ASSOCIATED TO TROPICAL
DEPRESSION NINE-E CURRENTLY LOCATED ABOUT 110 NM S OF THE GULF
OF TEHUANTEPEC GENERATING BROAD CYCLONIC FLOW AND CONVECTION
THAT REACHES AS FAR NORTH AS THE BAY OF CAMPECHE. THE REMAINDER
OF THE GULF IS UNDER THE INFLUENCE OF THE EASTERN FLOW ALOFT
MENTIONED ABOVE AND THIS SUPPORTS A 1016 MB SURFACE HIGH
CENTERED OVER THE CENTRAL GULF NEAR 26N91W. CLEAR SKIES ARE
NOTED ELSEWHERE ON NIGHT VISION SATELLITE IMAGERY UNDER LIGHT
ANTICYCLONIC WINDS.

CARIBBEAN SEA...
CONVERGENT LOW-LEVEL SOUTHEASTERLY FLOW DOMINATES ACROSS THE
WESTERN CARIBBEAN W OF 79W S OF 18N...INCLUDING PORTIONS OF
CENTRAL AMERICA. THIS AREA OF CONVECTION IS MOVING AROUND AND
INTO THE BROAD CYCLONIC CIRCULATION GENERATED BY TROPICAL
DEPRESSION NINE-E CURRENTLY LOCATED OVER THE EASTERN PACIFIC
WATERS ABOUT 110 NM S OF THE GULF OF TEHUANTEPEC. AN ELONGATED
UPPER LEVEL LOW LOCATED NE OF THE BAHAMAS EXTENDS UPPER LEVEL
TROUGHINESS ACROSS HISPANIOLA...THE WINDWARD PASSAGE...AND
JAMAICA...CONTINUING WESTWARD TO NEAR 18N80W...GENERATING
SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 20 NM ON EITHER SIDE
OF THE UPPER LEVEL TROUGH AXIS. THE ITCZ AXIS EXTENDS ACROSS THE
FAR SW CARIBBEAN ALONG 11N AND IS ALSO PROVIDING LOW-LEVEL FOCUS
FOR SCATTERED SHOWERS AND ISOLATED TSTMS OVER PORTIONS OF
NICARAGUA...COSTA RICA...PANAMA...AND NORTHERN COLOMBIA. WHILE
MUCH OF THE EASTERN CARIBBEAN BETWEEN 65W-76W IS UNDER
RELATIVELY CLEAR SKIES...A SURFACE TROUGH IS OVER THE LESSER
ANTILLES S OF 18N GENERATING SCATTERED SHOWERS AND ISOLATED
TSTMS E OF 65W.

ATLANTIC OCEAN...
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER MOST OF
THE WESTERN ATLC W OF 73W...PRODUCED BY UPPER LEVEL DIFFLUENT NE
FLOW AROUND AN ANTICYCLONIC CIRCULATION CENTERED OVER THE SE
CONUS AND AN ELONGATED UPPER LEVEL LOW LOCATED NE OF THE BAHAMAS
NEAR 24N74W. THE UPPER LEVEL LOW IS ALSO PROVIDING LOW LEVEL
MOISTURE TO A RATHER WEAK TROPICAL WAVE ALONG 69W...PRODUCING
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-29N BETWEEN
62W-70W. ELSEWHERE ACROSS THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC...SURFACE RIDGING DOMINATES THE ATLC N OF 25N
ANCHORED BY A 1025 MB HIGH CENTERED NEAR 32N29W...MAINTAINING
GENERALLY FAIR WEATHER CONDITIONS E OF 62W.

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

$$

GARCIA




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