[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUL 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2350 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BONNIE WAS DOWNGRADED TO TROPICAL DEPRESSION AT
2100 UTC DURING LANDFALL OVER SOUTHERN FLORIDA PENINSULA. AS OF
JUL 24 AT 0000 UTC...BONNIE IS OVER THE FAR EASTERN GULF OF
MEXICO CENTERED NEAR 26.4N 82.5W MOVING WNW NEAR 16 KT. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. THIS SYSTEM IS EMBEDDED
IN A REGION OF DEEP LAYER MOISTURE AS NOTED ON TOTAL
PRECIPITABLE WATER IMAGERY. WATER VAPOR IMAGERY INDICATES AN
BROAD UPPER LEVEL LOW SPINNING NEAR 27N92W. THIS UPPER LEVEL
FEATURE IS PROVIDING CONSIDERABLE MOISTURE ALOFT INTO BONNIE AND
FURTHER ENHANCING THE CONVERGENCE WITH THIS SYSTEM...PRODUCING A
BROAD AREA OF SCATTERED MODERATE TO STRONG CONVECTION FROM 21N
TO 30N BETWEEN 78W AND 85W. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TILTED TROPICAL WAVE EXTENDS ALONG 18N32W 13N32W 8N35W MOVING W
5 TO 10 KT. SATELLITE DERIVED WINDS INDICATE LOW-LEVEL CYCLONIC
FLOW ABOUT THE WAVE AXIS IN THE NORTHERN EXTENT OF THE WAVE. THE
WAVE ALSO LIES AHEAD OF A SURGE IN DEEP LAYER MOISTURE EVIDENT
IN TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THIS WAVE IS
FOUND WITHIN A BROAD AREA OF SAHARAN AIR LAYER SUPPRESSING ANY
DEEP CONVECTION WITHIN THE WAVE AXIS AND SURROUNDINGS OF IT.

TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES ALONG 59W S OF
20N MOVING W 5 TO 10 KT. THE WAVE CONTINUES TO PROPAGATE WWD
ALONGSIDE A MAXIMUM IN DEEP LAYER MOISTURE EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY AND SATELLITE
DERIVED WINDS ALSO SHOW WEAK CYCLONIC CURVATURE IN THE VICINITY
OF THE WAVE AXIS. SAHARAN AIR LAYER IS IN THE VICINITY OF THE
WAVE. THEREFORE...THIS WAVE IS ONLY GENERATING ISOLATED SHOWERS
AND POSSIBLE THUNDERSTORMS FROM 10N TO 20N BETWEEN 58W AND 63W.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE WESTERN AFRICAN COAST OF
GUINEA NEAR 10N14W...WESTWARD ALONG 11N20W 14N30W 10N40W 10N50W
12N55W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
80 NM ON EITHER SIDE OF THE ITCZ EAST OF 24W. SCATTERED WEAK
CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE ITCZ WEST OF
24W.

...DISCUSSION...

THE GULF OF MEXICO...
SCATTERED GUSTY SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
TROPICAL DEPRESSION BONNIE CONTINUE TO IMPACT THE EASTERN GULF
OF MEXICO. FOR MORE INFORMATION REGARDING BONNIE...SEE SPECIAL
FEATURES ABOVE. A SURFACE TROUGH EXTENDS INTO THE NE GULF ACROSS
THE FLORIDA PANHANDLE ALONG 31N85W TO 29N87W. SCATTERED SHOWERS
AND THUNDERSTORMS ARE WITHIN 40 NM OF THE AXIS. SCATTERED
SHOWERS AND THUNDERSTORMS ARE ALSO ACROSS THE SOUTHWESTERN GULF
WEST OF 91W SOUTH OF 23N. THIS ACTIVITY IS ASSOCIATED WITH AN
AREA OF LOW PRESSURE THAT HAS MOVED INLAND OVER MEXICO. WATER
VAPOR IMAGERY SHOWS DRY AIR ALOFT WRAPPING AROUND AN UPPER LEVEL
LOW SPINNING NEAR 27N92W...KEEPING MUCH OF THE CENTRAL AND
NORTHWEST GULF UNDER CLEAR SKIES. EXPECT SHOWER AND
THUNDERSTORMS TO CONTINUE TO IMPACT THE EASTERN GULF WATERS AS
BONNIE MOVES WEST-NORTHWEST TO NEAR THE COASTAL WATERS OF
MISSISSIPPI...ALABAMA...AND WESTERN FLORIDA PANHANDLE OVER THE
NEXT 24 HOURS.

THE CARIBBEAN SEA...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO LINGER OVER THE
NORTHERN CARIBBEAN AND INLAND PORTIONS OF THE GREATER ANTILLES
NORTH OF 14N BETWEEN 64W AND 80W. THIS GROUP OF ISLANDS HAVE
ALREADY RECEIVED CONSIDERABLE AMOUNTS OF RAINFALL FROM WHAT IS
NOW TROPICAL DEPRESSION BONNIE. THE CONTINUATION OF RAINFALL
ACROSS THESE AREAS INCREASES THE THREAT OF FLOODING AND
POTENTIAL MUDSLIDES IN AREAS OF HIGH SATURATED TERRAIN. BROAD
CYCLONIC CIRCULATION ALOFT AROUND AN UPPER LEVEL LOW SPINNING
NORTH OF THE CARIBBEAN SEA NEAR 20N68W IS PRODUCING ALL THIS
WEATHER OVER THIS REGION. DRY AIR INTRUSION FROM THE NORTH
CENTRAL ATLANTIC IS FURTHER MAINTAINING THE UPPER LOW AND
ENHANCING THE CONVECTION GENERATED BY IT. EXPECT SHOWERS AND
THUNDERSTORMS TO CONTINUE OVER THE MENTIONED AREA AS THE UPPER
LEVEL LOW MOVES SW TOWARDS THE SE BAHAMAS. A TROPICAL WAVE IS
JUST EAST OF THE LESSER ANTILLES GENERATING ISOLATED SHOWERS AND
POSSIBLE THUNDERSTORMS OVER THE FAR EASTERN CARIBBEAN EAST OF
63W.

THE ATLANTIC OCEAN...
ONLY A FEW SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS REMAIN
OVER THE NORTHERN BAHAMAS NORTH OF 24N FROM THE PASSAGE OF
TROPICAL DEPRESSION BONNIE...NOW OVER THE EASTERN GULF WATERS.
DRY AIR ALOFT COVERS MUCH OF THE WESTERN ATLC KEEPING CONDITIONS
FAIR. HOWEVER...BROAD CYCLONIC CIRCULATION ALOFT AROUND AN UPPER
LEVEL LOW SPINNING NEAR 20N68W IS PRODUCING SHOWERS AND
THUNDERSTORMS ACROSS PUERTO RICO AND HISPANIOLA SOUTH OF 22N
BETWEEN 63W-73W. DRY AIR INTRUSION FROM THE NORTH CENTRAL
ATLANTIC IS FURTHER MAINTAINING THE UPPER LOW AND ENHANCING THE
CONVECTION GENERATED BY IT. FARTHER EAST...SURFACE RIDGING
DOMINATES THE REMAINDER OF THE BASIN ANCHORED BY A 1031 MB HIGH
CIRCULATING OVER THE AZORES NEAR 38N27W PROVIDING FAIR
CONDITIONS ACROSS THE AREA.

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

$$

GARCIA




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