[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271111
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU SEP 27 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
VALID THROUGH 1015 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM NADINE AT 26/0900 UTC IS NEAR
28.9N 31.5W. NADINE IS ABOUT 590 NM/1095 KM TO THE SOUTH-
SOUTHWEST OF THE AZORES. NADINE IS MOVING SOUTHWESTWARD
5 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB.
THE MAXIMUM SUSTAINED WIND SPEEDS ARE 50 KNOTS WITH GUSTS
TO 60 KNOTS. TROPICAL STORM FORCE WINDS EXTEND AWAY FROM
THE CENTER OF NADINE AS FAR AS 110 NM IN THE NORTHEASTERN
QUADRANT...60 NM IN THE SOUTHEASTERN QUADRANT...80 NM IN
THE SOUTHWESTERN QUADRANT...AND TO 120 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 STRONG FROM 28N TO 31N BETWEEN
30W AND 33W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 31W/32W TO THE SOUTH
OF 17N MOVING WESTWARD 15 KNOTS DURING THE LAST 24 HOURS. THIS
POSITION IS BASED ON STUDYING LONG-TERM SATELLITE IMAGERY.
RAINSHOWERS ARE POSSIBLE FROM 8N TO 17N BETWEEN 30W AND 35W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 74W/75W...FROM
SOUTHEASTERN CUBA IN THE WINDWARD PASSAGE TO COASTAL COLOMBIA.
THE WAVE IS MOVING WESTWARD 15 KNOTS DURING THE LAST 24 HOURS.
THE TROPICAL WAVE IS JUST TO THE EAST OF AN UPPER LEVEL TROUGH
THAT PASSES THROUGH THE WINDWARD PASSAGE TO A 13N75W CYCLONIC
CIRCULATION CENTER TO THE GULF OF URABA OF COLOMBIA.
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.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 14N17W
TO 9N30W 8N40W. THE ITCZ CONTINUES FROM 8N40W TO 7N51W.
CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG WITHIN
60 NM ON EITHER SIDE OF 7N12W 6N15W 5N19W...SCATTERED STRONG
FROM 14N TO 18N BETWEEN 23W AND 30W...BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND WIDELY SCATTERED MODERATE TO ISOLATED
STRONG ELSEWHERE TO THE SOUTH OF 18N TO THE EAST OF 47W.

...DISCUSSION...

THE GULF OF MEXICO...

BROAD AND LARGE-SCALE UPPER LEVEL ANTICYCLONIC WIND FLOW
MOVES ACROSS MEXICO...FROM THE EASTERN PACIFIC OCEAN AND
TROPICAL STORM NADINE...INTO THE WESTERN HALF OF THE GULF
OF MEXICO. THE ANTICYCLONIC WIND FLOW IS PUSHING HIGH LEVEL
MOISTURE ACROSS MEXICO...INTO THE GULF OF MEXICO TO THE WEST
OF 90W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE
PRECIPITATION IS TO THE SOUTH OF 28N TO THE WEST OF 87W.

THE REMAINS OF A MIDDLE LEVEL TO UPPER LEVEL TROUGH ARE
MOVING THROUGH THE EASTERN SECTION OF THE AREA. BROKEN
TO OVERCAST MULTILAYERED CLOUDS AND ISOLATED MODERATE
CONVECTIVE PRECIPITATION ARE TO THE SOUTH OF 27N TO THE
EAST OF 87W. THE FRONTAL BOUNDARY THAT WAS CUTTING ACROSS
THE BAHAMAS INTO THE FLORIDA STRAITS HAS WEAKENED AND
DISSIPATED.

A SURFACE RIDGE PASSES THROUGH ALABAMA...THROUGH THE
SOUTHEASTERN HALF OF LOUISIANA...TOWARD THE SOUTHWESTERN
CORNER OF THE GULF OF MEXICO.

THE CARIBBEAN SEA...

AN UPPER LEVEL TROUGH PASSES THROUGH THE WINDWARD PASSAGE
TO A 13N75W CYCLONIC CIRCULATION CENTER TO THE GULF OF URABA OF
COLOMBIA. A TROPICAL WAVE IS ALONG 74W/75W...FROM SOUTHEASTERN
CUBA IN THE WINDWARD PASSAGE TO COASTAL COLOMBIA. BROKEN TO
OVERCAST MULTILAYERED CLOUDS AND ISOLATED MODERATE CONVECTIVE
PRECIPITATION COVER THE CARIBBEAN SEA AND THE SOUTHERN BAHAMAS
FROM THE COLOMBIA COASTAL WATERS TO 23N IN THE ATLANTIC OCEAN
BETWEEN 70W AND 81W. STRONG CONVECTIVE PRECIPITATION IS IN
ONE CLUSTER FROM 11N TO 12N BETWEEN 80W AND 81W. ISOLATED
MODERATE CONVECTIVE PRECIPITATION IS IN THE NICARAGUA COASTAL
WATERS.

THE SOUTHERN END OF AN UPPER LEVEL TROUGH PASSES THROUGH THE
YUCATAN CHANNEL...INTO THE NORTHWESTERN CORNER OF THE AREA.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION
IS ALONG THE COAST OF THE YUCATAN PENINSULA AND BELIZE...AND IN
THE HONDURAS COASTAL WATERS. THE PRECIPITATION ALSO IS TAKING
PLACE IN AN AREA OF UPPER LEVEL DIFFLUENT WIND FLOW BETWEEN THE
13N75W CYCLONIC CENTER AND THE TROUGH.

THE MONSOON TROUGH IS ALONG 8N73W...THROUGH 8N81W IN PANAMA...
BEYOND SOUTHERN COSTA RICA. CONVECTIVE PRECIPITATION...SCATTERED
MODERATE TO STRONG IN COLOMBIA FROM 5N TO 8N BETWEEN 73W AND
77W.

THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH EXTENDS FROM A 30N47W CYCLONIC CIRCULATION
CENTER TO 25N49W...TO A 20N55W CYCLONIC CIRCULATION CENTER...
WESTWARD TO THE MONA PASSAGE THAT IS BETWEEN PUERTO RICO AND
HISPANIOLA. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS BETWEEN
THE 20N55W CYCLONIC CENTER AND THE MONA PASSAGE FROM 14N TO 23N.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED
STRONG WITHIN 60 TO 90 NM ON EITHER SIDE OF 25N45W 21N57W.
A SURFACE TROUGH IS ALONG 23N52W 19N54W 16N54W. WIDELY SCATTERED
TO SCATTERED MODERATE FROM 11N TO 17N BETWEEN 48W AND 60W.

A 1015 MB HIGH PRESSURE CENTER IS NEAR 25N24W. SURFACE
ANTICYCLONIC WIND FLOW IS WITHIN 180 NM OF THE CENTER IN THE
NORTHERN SEMICIRCLE...AND WITHIN 240 NM OF THE CENTER IN THE
SOUTHERN SEMICIRCLE. A SECOND SURFACE RIDGE EXTENDS FROM
1027 MB HIGH PRESSURE CENTER THAT IS NEAR 39N46W TO 30N42W AND
20N37W.

PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...
FOR DETAILS ABOUT TROPICAL STORM NADINE.

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

$$
MT





This weather bulletin was brought to you by:
www.nashvilleweather.net