[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIX WAS UPGRADED AT 12/2100 UTC. T.D. SIX IS
CENTERED NEAR 36.0N 63.9W AT 12/2100 UTC 0R ABOUT ABOUT 225 NM N
OF BERMUDA MOVING E-NE AT 14 KT. ESTIMATED CENTRAL PRESSURE IS
1011 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUST TO 40
KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

THE 1011 MB LOW THAT WAS CENTERED NEAR 18N45W HAS OPENED UP INTO
A SURFACE TROUGH THAT EXTENDS FROM 22N47W TO 16N47W. IT IS
EXPECTED THAT THE SURFACE LOW WILL REFORM OVER THE NEXT 24
HOURS. CLUSTERS OF SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM 18N43W TO 21N51W.
UPPER-LEVEL WINDS HAVE BECOME LESS FAVORABLE FOR DEVELOPMENT
DURING THE PAST SEVERAL HOURS. THERE REMAINS THE POTENTIAL FOR
SLOW DEVELOPMENT OF THIS SYSTEM AND IT HAS A MEDIUM CHANCE OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

A 1010 MB LOW IS IN THE TROPICAL ATLC NEAR 11N31W WITH A
TROPICAL WAVE EXTENDING TO 16N31W. THIS LOW IS EMBEDDED WITHIN
THE MONSOON TROUGH. MODERATE TO DENSE CLOUD COVER WITH EMBEDDED
ISOLATED SHOWERS COVER THE AREA FROM 7N-14N BETWEEN 30W-39W.
SOME SLOW DEVELOPMENT IS POSSIBLE OVER THE NEXT SEVERAL DAYS AS
THIS SYSTEM MOVES W AT 13-17 KT. THIS SYSTEM HAS A MEDIUM CHANCE
OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

SURFACE TROUGH EXTENDS FROM 30N54W THROUGH A 1014 MB LOW NEAR
25N57W TO 22N60W. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE WITHIN 200 NM OF LINE FROM 27N55W TO 21N63W.
THIS SYSTEM HAS BECOME A LITTLE BETTER ORGANIZED THIS AFTERNOON.
CONTINUED SLOW DEVELOPMENT IS POSSIBLE DURING THE NEXT COUPLE OF
DAYS AS THE LOW MOVES W-SW OR W AT ABOUT 8 KT. THIS SYSTEM HAS A
MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS.

...TROPICAL WAVES...

TROPICAL WAVE IN THE W CARIBBEAN IS ANALYZED ALONG 81W/81W
BETWEEN 12N-21N MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN
A BROAD AREA OF DEEP LAYERED MOISTURE AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY WITH NO ASSOCIATED SHOWERS/DEEP
CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INTO THE E TROPICAL ATLC OFF W AFRICA
NEAR 18N16W EXTENDING THROUGH THE 1010 MB SURFACE LOWS IN THE
SPECIAL FEATURES ABOVE TO 14N41W. SCATTERED MODERATE/STRONG
CONVECTION IS MOVING OFF W AFRICA WITHIN 90/120 NM ALONG THE
COAST BETWEEN 7N-12N.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE DOMINATES THE W GULF ANCHORED INLAND OVER
CENTRAL TEXAS. AN UPPER TROUGH IS OVER E CONUS EXTENDS S OVER
FLORIDA AND INTO THE FAR W SUPPORTING A SURFACE TROUGH THAT
EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA BETWEEN WEST PALM
BEACH AND FORT MYERS TO 26N85W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE S OF THE SURFACE TROUGH INTO THE STRAITS OF
FLORIDA BETWEEN 80W-85W. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE INLAND AND ALONG THE N GULF COAST E OF THE
LOUISIANA/MISSISSIPPI BORDER TO OVER THE FLORIDA PANHANDLE. WEAK
SURFACE RIDGE CONTINUES TO DOMINATE THE GULF EXTENDING FROM THE
W ATLC ACROSS FLORIDA TO THE W GULF WITH A 1016 MB HIGH NEAR
27N91W LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR
SKIES THIS EVENING. SURFACE RIDGE WILL PREVAIL OVER THE GULF
THROUGH WED.

CARIBBEAN SEA...
AN INVERTED UPPER TROUGH EXTENDS FROM NE HONDURAS TO CENTRAL
CUBA GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ACROSS THE W CARIBBEAN N OF 16N W OF 78W. A BROAD
UPPER RIDGE ANCHORED IN THE CENTRAL ATLC EXTENDS S OVER THE
REMAINDER OF THE CARIBBEAN. THE MONSOON TROUGH EXTENDS FROM
COLOMBIA NEAR 11N75W INTO THE E PACIFIC REGION NEAR THE PANAMA/
COSTA RICA BORDER GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 15N W OF 80W TO INLAND OVER W PANAMA AND
CENTRAL AMERICA WITH ISOLATED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE S OF 12N TO INLAND OVER COLOMBIA AND E PANAMA
BETWEEN 73W-80W. AFTERNOON THUNDERSTORMS HAVE AGAIN DEVELOPED
OVER CUBA MOVING INTO THE ADJACENT COASTAL WATERS LEAVING THE
ENTIRE E CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS EVENING.
EASTERLY TRADE WINDS WILL DIMINISH SUN AND MON AS THE SURFACE
RIDGE IN THE W ATLC WEAKENS AND SHIFTS N. TROPICAL WAVE IN THE W
CARIBBEAN WILL DISSIPATE AS IT MOVES OVER CENTRAL AMERICA BY
EARLY SUN. THE SURFACE TROUGH NEAR 47W IN THE SPECIAL FEATURES
WILL MOVE ACROSS THE W ATLC JUST E OF THE LEEWARD ISLANDS LATE
SAT THROUGH SUN MORNING...POSSIBLY AS A TROPICAL CYCLONE.

ATLANTIC OCEAN...
AN UPPER TROUGH IS OVER THE E CONUS INTO THE W ATLC N OF 28N W
OF 77W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 31N76W
ALONG 29N78W ACROSS FLORIDA NEAR WEST PALM BEACH INTO THE GULF
OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN
90 NM E OF THE SURFACE TROUGH N OF 29N AND INLAND OVER THE
FLORIDA PENINSULA. AN UPPER RIDGE IS ANCHORED TO THE SE NEAR
25N70W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 60 NM OF LINE FROM 28N69W TO 25N74W. A WEAK SURFACE RIDGE
COVERS THE REMAINDER OF THE W ATLC ANCHORED BY A 1019 MB HIGH
NEAR 27N67W AND EXTENDS A RIDGE AXIS ACROSS FLORIDA INTO THE
GULF OF MEXICO. AN UPPER TROUGH EXTENDS INTO THE CENTRAL ATLC
THROUGH 32N55W TO 24N58W SUPPORTING THE SURFACE TROUGH/1014 MB
IN THE SPECIAL FEATURES. A BROAD SURFACE RIDGE COVERS THE
REMAINDER OF THE CENTRAL INTO THE E ATLC ANCHORED BY A 1026 MB
HIGH ABOUT 400 NM SW OF THE AZORES LEAVING THE E ATLC N OF 20N
UNDER MOSTLY FAIR CONDITIONS THIS EVENING. THE SURFACE TROUGH IN
THE W ATLC WILL LINGER THROUGH SAT. SURFACE RIDGE WILL WEAKEN
AND SHIFT N THROUGH MON AS THE SURFACE TROUGH/1014 MB LOW IN THE
SPECIAL FEATURES MOVES INTO THE W ATLC LATE SAT AND DISSIPATES
TUE ACROSS THE BAHAMAS. THE 1011 MB LOW IN THE SPECIAL FEATURES
WILL APPROACH 65W MON AND MOVE OVER THE W TROPICAL ATLC LATE MON
THROUGH TUE...POSSIBLY A TROPICAL CYCLONE. THE SURFACE TROUGH
NEAR 47W IN THE SPECIAL FEATURES WILL MOVE ACROSS THE W ATLC
JUST E OF THE LEEWARD ISLANDS LATE SAT THROUGH SUN MORNING...
POSSIBLY AS A TROPICAL CYCLONE. THE 1010 MB LOW IN THE SPECIAL
FEATURES WILL APPROACH THE W TROPICAL ATLC LATE MON INTO
TUE...POSSIBLY AS A TROPICAL CYCLONE.


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

$$
PAW




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