[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...SPECIAL FEATURES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 18N29W 14N30W...TO
A 1011 MB LOW PRESSURE CENTER THAT IS NEAR 11N ALONG THE WAVE.
RAINSHOWERS AND POSSIBLE THUNDERSTORMS ARE FROM 7N TO 14N
BETWEEN 28W AND 40W. ENVIRONMENTAL CONDITIONS GRADUALLY ARE
BECOMING MORE CONDUCIVE FOR DEVELOPMENT INTO A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS.

A 1011 MB LOW PRESSURE CENTER IS NEAR 18N45W. THIS LOW CENTER
HAS BROKEN AWAY FROM THE MONSOON TROUGH. THE LATEST SATELLITE
DERIVED WIND DATA SHOW THAT THE LOW CENTER HAS OPENED INTO A
SURFACE TROUGH. IT WILL BE DEPICTED THIS WAY FOR THE 12/1800 UTC
SURFACE MAP. WIDELY SCATTERED MODERATE RAINSHOWERS TO ISOLATED
STRONG THUNDERSTORMS ARE FROM 17N TO 21N BETWEEN 44W AND 50W. IT
IS STILL POSSIBLE FOR A SURFACE LOW CENTER TO RE-DEVELOP...AND
LATER INTENSIFY INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

A 1012 MB LOW PRESSURE CENTER IS NEAR 35N67W. SCATTERED MODERATE
RAINSHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 34N TO 37N
BETWEEN 64W AND 65W. A FRONTAL BOUNDARY CURVES FROM THE LOW
CENTER TO 32N70W 31N75W. A SURFACE TROUGH CONTINUES FROM 31N75W
TO THE FLORIDA EAST COAST NEAR 28N...AND INTO THE GULF OF MEXICO
NEAR 25N84W. WIDELY SCATTERED MODERATE RAINSHOWERS TO ISOLATED
STRONG THUNDERSTORMS ARE FROM 30N TO 34N BETWEEN 66W AND 80W...
AND WITHIN 240 NM TO THE EAST AND SOUTHEAST OF THE LINE THAT GOES
FROM 30N78W TO 27N80W TO 26N85W. ISOLATED MODERATE RAINSHOWERS
ARE IN THE BAHAMAS AROUND ANDROS ISLAND. RAINSHOWERS ARE POSSIBLE
ELSEWHERE IN THE SURFACE SOUTHEASTERLY WIND FLOW THAT IS TO THE
NORTH OF 20N TO THE WEST OF 70W.

A 1013 MB LOW PRESSURE CENTER IS NEAR 25N55W. A SURFACE TROUGH
IS ALONG 30N53W...THROUGH THE LOW CENTER...TO 20N58W.
ISOLATED MODERATE RAINSHOWERS ARE WITHIN 90 NM ON EITHER SIDE OF
31N53W 26N55W 24N56W 20N60W. SCATTERED MODERATE RAINSHOWERS TO
ISOLATED STRONG THUNDERSTORMS ARE ELSEWHERE TO THE WEST OF THE
LOW AND TROUGH...FROM 20N TO 26N BETWEEN 58W AND 63W IN THE
SURFACE NORTHERLY AND NORTHEASTERLY WIND FLOW. SLOW DEVELOPMENT
INTO A TROPICAL CYCLONE IS POSSIBLE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 80W/81W TO THE SOUTH OF
20N. ISOLATED MODERATE RAINSHOWERS ARE FROM 14N TO CUBA BETWEEN
77W AND LAND.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH THE COAST OF AFRICA NEAR 21N17W
TO 11N26W 11N30W 14N34W 14N37W. THE 1011 MB LOW PRESSURE CENTER
THAT IS NEAR 18N45W HAS BROKEN AWAY FROM THE MONSOON TROUGH.
THIS HAS CAUSED A BREAKDOWN IN THE MONSOON TROUGH/ITCZ TO THE
WEST OF 37W. THE ITCZ IS NOT DEPICTED TO THE WEST OF 37W.
SCATTERED MODERATE RAINSHOWERS TO ISOLATED STRONG THUNDERSTORMS
ARE FROM 5N TO 7N BETWEEN 13W AND 16W. RAINSHOWERS ARE POSSIBLE
FROM 11N TO 12N BETWEEN 17W AND 18W...AND FROM 5N TO 10N TO THE
WEST OF 43W.

...DISCUSSION...

THE GULF OF MEXICO...

AN UPPER LEVEL SHEAR AXIS PASSES THROUGH 31N75W IN THE ATLANTIC
OCEAN...CROSSING FLORIDA AROUND 28N...INTO A WEAK CYCLONIC
CIRCULATION CENTER THAT IS NEAR 26N84W IN THE GULF OF MEXICO...
TO ANOTHER CYCLONIC CIRCULATION CENTER THAT IS IN THE
SOUTHWESTERN CORNER OF THE AREA NEAR 20N94W. A SURFACE TROUGH
CONTINUES FROM 31N75W IN THE ATLANTIC OCEAN...TO THE FLORIDA
EAST COAST NEAR 28N...AND INTO THE GULF OF MEXICO NEAR 25N84W.
WIDELY SCATTERED MODERATE RAINSHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE WITHIN 240 NM TO THE EAST AND SOUTHEAST OF
THE LINE THAT GOES FROM 30N78W TO 27N80W TO 26N85W. ISOLATED
MODERATE RAINSHOWERS ARE IN THE BAHAMAS AROUND ANDROS ISLAND.
A SURFACE TROUGH PASSES THROUGH THE FLORIDA PANHANDLE NEAR
31N85W...INTO THE COASTAL WATERS OF ALABAMA AND MISSISSIPPI...
NORTHWESTWARD BEYOND SOUTHEASTERN LOUISIANA. SCATTERED MODERATE
RAINSHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 29N TO
30N BETWEEN 85W AND 88W.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS ALONG 80W/81W TO THE SOUTH OF 20N. ISOLATED
MODERATE RAINSHOWERS ARE FROM 14N TO CUBA BETWEEN 77W AND LAND.
AN UPPER LEVEL TROUGH EXTENDS FROM AN ATLANTIC OCEAN 17N57W
CYCLONIC CIRCULATION CENTER INTO THE CARIBBEAN SEA NEAR
15N68W...TO A CYCLONIC CENTER THAT IS NEAR 15N75W...TO
A SECOND CYCLONIC CENTER THAT IS NEAR 16N83W TO GUATEMALA.
RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE EAST OF 80W. THE
MONSOON TROUGH PASSES THROUGH 10N75W IN NORTHERN COLOMBIA...
BEYOND NORTHERN COSTA RICA...INTO THE EASTERN PACIFIC OCEAN.
SCATTERED STRONG RAINSHOWERS AND THUNDERSTORMS ARE TO THE
SOUTH OF 13N AT THE COAST OF NICARAGUA AND 12N75W.

THE ATLANTIC OCEAN...
A FRONTAL BOUNDARY CURVES FROM THE 35N67W LOW PRESSURE CENTER TO
32N70W 31N75W. A SURFACE TROUGH CONTINUES FROM 31N75W TO THE
FLORIDA EAST COAST NEAR 28N...AND INTO THE GULF OF MEXICO NEAR
25N84W. WIDELY SCATTERED MODERATE RAINSHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE FROM 30N TO 34N BETWEEN 66W AND 80W...AND
WITHIN 240 NM TO THE EAST AND SOUTHEAST OF THE LINE THAT GOES
FROM 30N78W TO 27N80W TO 26N85W. ISOLATED MODERATE RAINSHOWERS
ARE IN THE BAHAMAS AROUND ANDROS ISLAND. RAINSHOWERS ARE
POSSIBLE ELSEWHERE IN THE SURFACE SOUTHEASTERLY WIND FLOW THAT
IS TO THE NORTH OF 20N TO THE WEST OF 70W.  BROAD SURFACE
ANTICYCLONIC WIND FLOW IS TO THE NORTH OF 22N TO THE EAST OF 50W.

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

$$
MT





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