[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311152
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 31 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

A TROPICAL WAVE IS MOVING ACROSS THE EASTERN TROPICAL ATLC
ANALYZED FROM 20N57W TO 11N54W. THIS WAVE IS NOW SEPARATED FROM
THE 1008 MB LOW CENTERED NEAR 13N51W. THESE TWO FEATURES ARE
EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE ON TPW PRODUCT.
THE CIRCULATION ASSOCIATED TO THE 1008 MB LOW HAS BECOME BETTER
ORGANIZED OVER THE PAST 6-12 HOURS. THUS...THIS SYSTEM IS CLOSE
TO BECOMING A TROPICAL DEPRESSION WITH A THREAT TO THE LESSER
ANTILLES AND PUERTO RICO. TROPICAL CYCLONE WATCHES OR WARNINGS
WOULD LIKELY BE REQUIRED FOR PARTS OF THESE GROUP OF ISLANDS.
INTERESTS IN THESE AREAS SHOULD CLOSELY MONITOR THE PROGRESS OF
THIS SYSTEM AS IT MOVES WNW AT 15 TO 20 KT. AN AIR FORCE
HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS
DISTURBANCE LATER THIS AFTERNOON. SCATTERED MODERATE TO STRONG
CONVECTION IS FROM 11N-16N BETWEEN 47W-59W.

...TROPICAL WAVES...

A TROPICAL WAVE IN THE ATLC IS ANALYZED FROM 24N38W TO 13N37W
MOVING W AT 15 KT. THIS WAVE IS LOCATED ALONG THE LEADING EDGE
OF A WEAK LOW LEVEL MOISTURE SURGE DEPICTED ON TOTAL
PRECIPITABLE WATER PRODUCT. WATER VAPOR IMAGERY INDICATES AN
UPPER LEVEL INVERTED TROUGH IS IN THE VICINITY OF THE WAVE. NO
SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.

A TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA AND THE YUCATAN
PENINSULA...ANALYZED FROM 23N88W TO 13N87W MOVING W AT 10-15 KT.
THE WAVE IS EMBEDDED WITHIN AN AREA OF DEEP MOISTURE THAT
COVERS MOST OF THE NW CARIBBEAN. BROAD LOW LEVEL CLOUD CYCLONIC
CURVATURE IS OBSERVED ON SATELLITE DATA. SCATTERED HEAVY SHOWERS
AND THUNDERSTORMS ARE AFFECTING THE W AND NW CARIBBEAN WATERS W
OF 80W...WITH THE STRONGEST CONVECTION NOTICED WITHIN 70-130 NM
OFF THE COASTS OF NORTHERN NICARAGUA AND WESTERN HONDURAS.
LOCALLY HEAVY RAINFALL TO PORTIONS OF CENTRAL AMERICA ARE
EXPECTED WITHIN THE NEXT 24 HOURS.

A TROPICAL WAVE CURRENTLY OVER WEST AFRICA IS EXPECTED TO ENTER
THE EAST ATLC WATERS OVER THE NEXT 24-36 HOURS. THE CONVECTION
ASSOCIATED TO THIS WAVE IS ALREADY OVER THE EAST TROPICAL ATLC
DISCUSSED BELOW.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS GUINEA-BISSAU IN WEST AFRICA
ENTERING THE ATLC ALONG 12N16W TO 9N19W TO 11N26W. THE ITCZ
CONTINUES FROM THIS POINT ALONG 12N33W 8N40W TO 12N49W...THEN
RESUMES S OF THE SPECIAL FEATURE TROPICAL WAVE NEAR 11N51W TO
THE COAST OF GUYANA IN SOUTH AMERICA NEAR 7N58W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 140 NM ON
EITHER SIDE OF THE ITCZ AXIS BETWEEN 38W-50W. THIS AREA OF
CONVECTION IS ALSO ASSOCIATED TO THE SPECIAL FEATURE TROPICAL
WAVE. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 7N-13N E
OF 22W ASSOCIATED TO THE NEXT TROPICAL WAVE THAT WILL BE
ENTERING THE EAST ATLC OVER THE NEXT 24-36 HOURS.

...DISCUSSION...

GULF OF MEXICO...
EASTERLY FLOW ALOFT IS OBSERVED ACROSS THE GULF WITH MODERATE
SUBSIDENCE NOTICED ON WATER VAPOR IMAGERY. THIS FLOW TURNS
ANTICYCLONIC AROUND AN UPPER RIDGE CENTERED OVER THE SE CONUS.
HOWEVER...AT SURFACE...A SURFACE TROUGH EXTENDS ACROSS THE SE
CONUS AND ENTERS THE DISCUSSION AREA THROUGH NORTHERN FLORIDA
ALONG 30N82W INTO THE NE GULF COAST NEAR 27N84W. SCATTERED HEAVY
SHOWERS AND THUNDERSTORMS ARE WITHIN 40 NM ON EITHER SIDE OF THE
TROUGH AXIS NOTED ON DOPPLER RADAR IMAGERY. A 1018 MB HIGH OVER
THE N CENTRAL GULF NEAR THE LOUISIANA COAST AT 29N92W. THIS
FEATURE IS KEEPING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE
DISCUSSION AREA N OF 23N. A TROPICAL WAVE IS MOVING OVER CENTRAL
AMERICA AND THE YUCATAN PENINSULA ALONG 88W S OF 23N. THIS
SYSTEM IS BRINGING SCATTERED SHOWERS AND THUNDERSTORMS TO THE S
AND SE GULF WATERS INCLUDING THE YUCATAN CHANNEL AND BAY OF
CAMPECHE S OF 23N. AS THE WAVE TRACKS W...MORE CONVECTION IS
EXPECTED OVER THE BAY OF CAMPECHE DURING THE NEXT 24-36 HOURS.

CARIBBEAN SEA...
A TROPICAL WAVE MOVES ACROSS CENTRAL AMERICA AND THE YUCATAN
PENINSULA. HOWEVER...SCATTERED HEAVY SHOWERS AND THUNDERSTORMS
LAG BEHIND THE WAVE...AFFECTING THE W AND NW CARIBBEAN WATERS W
OF 80W. THIS AREA OF CONVECTION AND MOISTURE WILL CONTINUE TO
MOVE OVER THE CENTRAL AMERICA TERRAIN IN THE NEXT 24 HOURS WITH
THE POTENTIAL TO GENERATE FLASH FLOODING ACROSS THE AREA. THE
MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM NORTHERN
COSTA RICA TO A WEAK 1011 MB LOW NEAR 10N82W INTO NORTHERN
COLOMBIA. THIS SYSTEM IS GENERATING SIMILAR CONVECTION TO THE
COASTAL WATERS WITHIN 70 NM OF COSTA RICA AND PANAMA. A WEAK
UPPER LEVEL TROUGH MOVES ACROSS THE N CENTRAL CARIBBEAN
SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE
SOUTHERN COASTAL WATERS OF HISPANIOLA N OF 15N BETWEEN 70W-74W
...AND OVER THE WINDWARD PASSAGE BETWEEN HAITI AND CUBA N OF
18N. THE REMAINDER OF THE CARIBBEAN BASIN IS EXPERIENCING FAIR
WEATHER CONDITIONS WITH ISOLATED MODERATE TO HEAVY SHOWERS
EMBEDDED IN THE MODERATE EASTERLY TRADE WINDS. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION WILL INVADE THE EASTERN
BASIN AND THE LESSER ANTILLES TODAY...ASSOCIATED TO THE SPECIAL
FEATURE SYSTEM MENTIONED ABOVE.

ATLANTIC OCEAN...
AN AREA OF SCATTERED WEAK SHOWERS IS NOTED ON SATELLITE DATA
OVER THE W ATLC WITHIN 30 NM ON EITHER SIDE OF A LINE FROM
32N67W TO 29N72W. THE REMAINDER OF THE DISCUSSION AREA
EXPERIENCES FAIR WEATHER INFLUENCED BY A STRONG 1032 MB HIGH
PRESSURE SYSTEM ANCHORED WEST OF THE AZORES NEAR 39N35W AND
EXTENDING A RIDGE AXIS SW TO THE BAHAMAS.

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

$$

GARCIA




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