[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151857 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT AUG 15 2009

CORRECTED DATE

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...
TROPICAL STORM ANA IS CENTERED NEAR 14.3N 48.3W AT 15/1500 UTC
OR ABOUT 875 NM EAST OF THE LEEWARD ISLANDS MOVING W AT 14
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22
KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS WITHIN
60 NM E SEMICIRCLE.

TROPICAL DEPRESSION THREE HAS FORMED OVER THE CENTRAL TROPICAL
NORTH ATLC. TROPICAL DEPRESSION THREE IS CENTERED NEAR 11.5N
34.0W AT 15/1500 UTC OR ABOUT 640 NM WEST-SOUTHWEST OF THE
CAPE VERDE ISLANDS. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH
GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. SCATTERED
MODERATE CONVECTION IS WITHIN 180 NM W SEMICIRCLE AND 150 NM SE
QUADRANT.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 81W/82W S OF 20N MOVING W 15 KT. THIS
WAVE IS ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED
ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. RECENT
VISIBLE SATELLITE IMAGERY INDICATES CYCLONIC TURNING ASSOCIATED
WITH LOW LEVEL CLOUDS NEAR THIS WAVE. THE 15/1200 UTC QUIKSCAT
PASS INDICATES WELL-DEFINED CYCLONIC CURVATURE IN THE LOW LEVEL
FLOW NEAR THIS WAVE...WITH E TO SE WINDS OF 15 TO 20 KT WITHIN
120 NM E OF THE WAVE AXIS AND E WINDS AROUND 10 KT WITHIN 120 W
OF THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM
EITHER SIDE OF THE WAVE AXIS S OF 19N. THIS CONVECTION IS BEING
SUPPORTED BY ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER
LEVEL LOW CENTERED NEAR 19N84W AND AN UPPER TROUGH EXTENDING
FROM THIS UPPER LOW TO 11N82W.

TROPICAL WAVE IS ALONG 93W/94W S OF 20N MOVING W NEAR 15 KT.
THIS WAVE IS ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE
BASED ON TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...SUBSIDENCE
AND DEEP LAYER DRY AIR IN NORTHWESTERLY FLOW ALOFT ARE
INHIBITING DEEP CONVECTION NEAR THIS WAVE OVER THE DISCUSSION
AREA. HOWEVER...THIS WAVE IS ASSOCIATED WITH DEEP CONVECTION IN
PORTIONS OF THE E PACIFIC REGION.  FOR MORE INFORMATION ON THIS
CONVECTION...SEE THE LATEST TROPICAL WEATHER DISCUSSION FOR
THE EASTERN PACIFIC OCEAN UNDER AWIPS/WMO HEADERS
MIATWDEP/AXPZ20 KNHC FOR MORE DETAILS.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 12N16W 13N22W 13N28W THEN ALONG
10N35W 10N49W 10N62W. NUMEROUS MODERATE/SCATTERED STRONG
CONVECTION IS FROM 8N-15N E OF 19W. SCATTERED MODERATE
CONVECTION IS FROM 7N-10N BETWEEN 43W-46W. SCATTERED MODERATE
CONVECTION IS FROM 8N-11N BETWEEN 55W-60W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH EXTENDS FROM AN UPPER LEVEL LOW OVER THE N
GULF NEAR 27N91W TO S MISSISSIPPI NEAR 30N89W. ATMOSPHERIC
INSTABILITY ASSOCIATED WITH THESE FEATURES IS SUPPORTING
SCATTERED SHOWERS AND THUNDERSTORMS FROM 25N-29N BETWEEN
88W-95W. ALSO...LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH OVER
THE NE GULF IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N
OF 28N E OF 88W. OVER THE SE GULF...UPPER LEVEL DIFFLUENCE IN
MOIST SOUTHEASTERLY FLOW ALOFT BETWEEN AN UPPER LEVEL HIGH OVER
THE SOUTHWEST NORTH ATLC AND AN UPPER LEVEL LOW OVER THE NW
CARIBBEAN IS SUPPORTING NUMEROUS SHOWERS AND THUNDERSTORMS FROM
23N-26N BETWEEN 80W-83W. THIS ACTIVITY IS BEING SUPPORTED BY LOW
LEVEL CONVERGENCE NEAR A SURFACE TROUGH OVER THE SE GULF
EXTENDING FROM NAPLES FLORIDA TO THE WESTERN FLORIDA KEYS.
ACROSS THE SW GULF...DEEP LAYER DRY AIR AND SUBSIDENCE
ASSOCIATED WITH A SURFACE RIDGE IS SUPPORTING GENERALLY FAIR
WEATHER.

CARIBBEAN SEA...
SCATTERED MODERATE CONVECTION IS OCCURRING OVER THE W CARIBBEAN
ASSOCIATED WITH THE TROPICAL WAVE ALONG 81W/82W S OF 20N AND AN
UPPER LEVEL LOW AND UPPER LEVEL TROUGH. SEE THE TROPICAL WAVES
SECTION ABOVE FOR MORE INFORMATION. ACROSS MUCH OF THE CENTRAL
AND E CARIBBEAN...DEEP LAYER DRY AIR AND GENERALLY FAIR WEATHER
IS OCCURRING. FRESH TRADE WINDS S OF A SURFACE RIDGE ARE
ADVECTING POCKETS OF LOW LEVEL MOISTURE AND ISOLATED SHOWERS
WESTWARD FROM 13N-17N E OF 73W. ACROSS THE FAR SE CARIBBEAN...AN
UPPER LEVEL TROUGH IN EASTERLY FLOW ALOFT IS SUPPORTING
SCATTERED SHOWERS AND THUNDERSTORMS S OF 13N E OF 64W.

ATLANTIC OCEAN...
AN UPPER LEVEL HIGH IS CENTERED OVER THE SW NORTH ATLC NEAR
30N76W. TO THE WEST OF THIS UPPER LEVEL HIGH...ATMOSPHERIC LIFT
IN MOIST SOUTHWESTERLY FLOW ALOFT IS SUPPORTING SCATTERED
SHOWERS AND THUNDERSTORMS N OF 29N W OF 77W. TO THE
E...ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL LOW
NEAR 24N66W IS SUPPORTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS FROM 23N-27N BETWEEN 65W-70W. ADDITIONALLY...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING
WITHIN 90 NM EITHER SIDE OF A SURFACE TROUGH EXTENDING FROM
24N62W TO 31N57W. ATMOSPHERIC LIFT IN SOUTHERLY FLOW ALOFT TO
THE E OF AN NORTH-TO-SOUTH-ELONGATED UPPER LEVEL LOW CENTERED
NEAR 26N52W IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS NW
OF TROPICAL STORM ANA FROM 18N-24N BETWEEN 51W-55W. FARTHER TO
THE E...A DEEP LAYER RIDGE IS PRESENT WITH AN ASSOCIATED 1025 MB
SURFACE HIGH CENTERED NEAR 33N33W.

$$
ARIEL COHEN/JOHN CANGIALOSI




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