[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE SEP 25 2012

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
VALID THROUGH 0515 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM NADINE AT 25/0300 UTC IS NEAR
32.2N 29.0W. NADINE IS ABOUT 360 NM/670 KM TO THE SOUTH-
SOUTHWEST OF THE AZORES. NADINE IS MOVING WESTWARD 6 KNOTS.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 40 KNOTS WITH GUSTS TO 50 KNOTS.
TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 90 NM IN THE
SOUTHERN SEMICIRCLE...150 NM IN THE NORTHEASTERN QUADRANT...
AND 160 NM IN THE NORTHWESTERN QUADRANT. PLEASE READ THE
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/
WTNT24 KNHC...AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC...
FOR MORE DETAILS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE
TO ISOLATED STRONG FROM 30N TO 32N BETWEEN 29W AND 32W.

...TROPICAL WAVE...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 60W TO THE SOUTH OF
18N...MOVING WESTWARD 15 KNOTS DURING THE LAST 24 HOURS.
RAINSHOWERS ARE POSSIBLE WITHIN 60 NM ON EITHER SIDE OF THE
TROPICAL WAVE. IT IS NOT EASY TO FIND PRECIPITATION THAT ONLY
ACCOMPANIES THE WAVE...BECAUSE OF THE MIDDLE LEVEL TO UPPER
LEVEL TROUGH THAT IS ALONG 20N65W 14N70W 10N79W.

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

THE MONSOON TROUGH PASSES THROUGH THE COASTAL GAMBIA TO 14N20W
15N24W 14N27W. THE ITCZ CONTINUES FROM 14N27W TO 10N33W 9N36W
10N42W 11N46W 10N50W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG
IN GUINEA-BISSAU AND IN SENEGAL TO THE SOUTH OF GAMBIA FROM 12N
TO 14N BETWEEN 14W AND 16W AND IN THE WATER FROM 12N TO 14N
BETWEEN 18W AND 20W...ISOLATED MODERATE ELSEWHERE FROM 3N TO 16N
TO THE EAST OF 53W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH CUTS THROUGH THE FLORIDA
PANHANDLE...TO 24N90W TO 19N92W IN THE SOUTHWESTERN CORNER OF
THE GULF OF MEXICO. COMPARATIVELY DRIER IN SUBSIDENCE IS TO THE
WEST OF THE FLORIDA PANHANDLE-TO-19N92W LINE. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE TO THE EAST OF
THE FLORIDA PANHANDLE-TO-19N92W LINE.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N73W IN
THE ATLANTIC OCEAN TO 30N76W. A COLD FRONT PASSES THROUGH 32N69W
IN THE ATLANTIC OCEAN...TO A 1015 MB LOW PRESSURE CENTER THAT
IS NEAR 28N75W. THE FRONT BECOMES DISSIPATING STATIONARY FROM
THE 1015 MB LOW PRESSURE CENTER THAT IS NEAR 28N75W...ON TOP
OF THE FLORIDA KEYS...TO 23N87W IN THE GULF OF MEXICO.
BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS
ARE TO THE WEST/NORTHWEST OF THE LINE THAT PASSES THROUGH 32N61W
TO 29N62W TO 22N71W.

THE CARIBBEAN SEA...

SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION
IS TO THE NORTHWEST OF THE LINE THAT PASSES THROUGH HONDURAS
NEAR 14N88W...BEYOND 20N76W IN SOUTHEASTERN CUBA.
THIS PRECIPITATION IS RELATED TO THE UPPER LEVEL DIFFLUENT WIND
FLOW FROM THE GULF OF MEXICO FLORID PANHANDLE TO 24N90W TO
19N92W MIDDLE TO UPPER LEVEL TROUGH.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 20N65W 14N70W
10N79W. THIS CYCLONIC WIND FLOW HAS BEEN IN THE CARIBBEAN SEA
FOR AT LEAST THE LAST 4 DAYS OR MORE. THE CYCLONIC CIRCULATION
CENTER FROM 24 HOURS AGO HAS WEAKENED AND DISSIPATED. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM VENEZUELA
COAST TO 11N BETWEEN 67W AND 69W AND JUST NORTH OF LAKE
MARACAIBO IN VENEZUELA WITHIN A 15 TO 30 NM RADIUS OF
11N72W...SCATTERED MODERATE TO ISOLATED STRONG FROM 13N
TO 16N BETWEEN 62W AND 66W...ISOLATED MODERATE ELSEWHERE
TO THE EAST OF THE LINE 20N64W 16N71W 14N71W 11N77W.

THE MONSOON TROUGH IS ALONG 9N/10N BETWEEN 75W IN COLOMBIA AND
88W IN THE EASTERN PACIFIC OCEAN. RAINSHOWERS ARE POSSIBLE IN
THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA TO THE SOUTH
OF 12N TO THE WEST OF 77W.

PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR DETAILS ABOUT 20 TO 25 KNOT
WINDS AND 8 FOOT SEA HEIGHTS FROM 12N TO 16N BETWEEN 71W AND 78W
FOR AT LEAST THE FIRST 24 HOURS OF THE FORECAST PERIOD.

THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH PASSES THROUGH 32N58W TO A 25N58W CYCLONIC
CIRCULATION CENTER...TO 20N58W. ISOLATED MODERATE TO LOCALLY
STRONG CONVECTIVE PRECIPITATION TO THE NORTH OF 24N BETWEEN
57W AND 59W.

A SURFACE TROUGH IS ALONG 23N47W 20N50W 18N51W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION
IS FROM 21N TO 22N BETWEEN 48W AND 49W.

A DEEP LAYER TROUGH EXTENDS AWAY FROM THE AREA THAT IS NEAR
TROPICAL STORM NADINE...TO 27N30W 22N36W 17N42W 11N43W.
COMPARATIVELY DRIER AIR IN SUBSIDENCE SPANS THE AREA OF THE
TROUGH AND IT INCLUDES THE ATLANTIC OCEAN THAT IS TO THE
SOUTH OF 30N TO THE EAST OF 30W...AND FROM 15N TO 23N
BETWEEN 30W AND 45W.

A SURFACE RIDGE PASSES THROUGH 32N53W TO 30N57W AND 21N67W.

PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...FOR DETAILS
ABOUT 8 TO 12 FOOT SEA HEIGHTS TO THE NORTH OF 20N TO THE EAST
OF 53W AT THE START OF THE FORECAST TIME. TROPICAL STORM NADINE
BEGINS TO BE A FACTOR AT 24 HOURS INTO THE FORECAST PERIOD...
NEAR 31.5N 30.5W...AND NEAR 29.9N 30.8W AT 48 HOURS INTO THE
FORECAST PERIOD.

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

$$
MT





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