[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310555
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...SPECIAL FEATURES...

A TROPICAL WAVE IS MOVING ACROSS THE EASTERN TROPICAL ATLC
ANALYZED FROM 20N55W TO A 1008 MB LOW CENTERED IN THE SOUTHERN
EXTENT OF THE WAVE NEAR 13N50W. THIS WAVE IS EMBEDDED WITHIN A
BROAD AREA OF DEEP MOISTURE ON TPW PRODUCT. BROAD CYCLONIC FLOW
IS WELL OBSERVED IN THE LOW LEVEL CLOUD PATTERN ON SATELLITE
IMAGERY. THE CIRCULATION 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
8N-16N BETWEEN 44W-57W.

...TROPICAL WAVES...

A TROPICAL WAVE IN THE ATLC IS ANALYZED FROM 24N36W TO 11N35W
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 23N87W TO 12N85W 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 COAST OF NORTHERN NICARAGUA AND EASTERN HONDURAS.
LOCALLY HEAVY RAINFALL TO PORTIONS OF CENTRAL AMERICA ARE
EXPECTED THROUGH OVER 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...
AND SUPPORTS A 1018 MB HIGH OVER THE NE GULF NEAR 28N87W. THIS
PATTERN IS KEEPING FAIR WEATHER CONDITIONS ACROSS THE DISCUSSION
AREA N OF 23N. A TROPICAL WAVE IS MOVING OVER CENTRAL AMERICA
AND THE YUCATAN PENINSULA ALONG 87W 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 CENTRAL AMERICA TERRAIN OVER THE NEXT 24 HOURS WITH
THE POTENTIAL FOR FLASH FLOODING ACROSS THE AREA. THE MONSOON
TROUGH EXTENDS ACROSS THE SW CARIBBEAN GENERATING SIMILAR
CONVECTION TO THE COASTAL WATERS WITHIN 70 NM OF COSTA
RICA...PANAMA...AND COLOMBIA. 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 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.

ATLANTIC OCEAN...
A WEAK SURFACE TROUGH IS OVER THE W ATLC ANALYZED FROM 34N68W TO
29N71W GENERATING SCATTERED WEAK SHOWERS WITHIN 20 NM ON EITHER
SIDE OF THE AXIS. THE REMAINDER OF THE DISCUSSION AREA
EXPERIENCES FAIR WEATHER INFLUENCED BY A STRONG 1031 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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