[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 092357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 09 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL STORM GABRIELLE AT 10/0000 UTC IS NEAR
36.0N 75.8W...OR ABOUT 7 NM/13 KM WEST OF KILL DEVIL HILLS NORTH
CAROLINA...AND ABOUT 48 NM/90 KM NORTH-NORTHWEST OF CAPE HATTERAS
NORTH CAROLINA. GABRIELLE IS MOVING NORTH 10 KT. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 45 KT WITH GUSTS TO 55 KT. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. PLEASE REFER
TO THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/
WTNT22 KNHC AND/OR THE PUBLIC ADVISORY MIATCPAT2/WTNT32 KNHC FOR
MORE DETAILS. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS WITHIN 30 TO 45 NM ON EITHER SIDE OF 34N BETWEEN
76W AND 78W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 33W/34W SOUTH OF 16N
MOVING WEST 15 KT. NUMEROUS STRONG THUNDERSTORMS IN CELLS FROM
9N TO 10N BETWEEN 36W AND 37W...AND FROM 11N TO 12N BETWEEN 37W
AND 38W. ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS ARE
ELSEWHERE AND IN THE ITCZ FROM 6N TO 12N BETWEEN 34W AND 39W.
A 1010 MB LOW PRESSURE CENTER IS NEAR 10N ALONG THE WAVE.
CONDITIONS APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT OF
THIS SYSTEM DURING THE NEXT COUPLE OF DAYS AS IT MOVES
WEST-NORTHWESTWARD ABOUT 15 MPH.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 57W/58W SOUTH
OF 21N MOVING WEST 15 KT. A PRONOUNCED MIDDLE LEVEL CYCLONIC
CIRCULATION CENTER IS NEAR 18N ALONG THE WAVE. BROKEN
TO OVERCAST MULTILAYERED CLOUDS FROM 16N TO 20N BETWEEN 55W
AND 60W. PRECIPITATION HAS BEEN DISSIPATING DURING THE LAST
4 TO 5 HOURS IN THE AREA OF CLOUDINESS. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 14.5N TO
16N BETWEEN 59W AND 61W APPROACHING THE CARIBBEAN SEA ISLANDS
FROM MARTINIQUE TO JUST SOUTH OF GUADELOUPE.

A GULF OF MEXICO TROPICAL WAVE IS ALONG 91W/92W SOUTH OF 22N
MOVING WEST 15 KT. THE AXIS OF THE WAVE CROSSES MEXICO AND
WESTERN GUATEMALA. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION
CENTER IS NEAR 22N92W IN THE SOUTHWESTERN CORNER OF THE GULF
OF MEXICO. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE INLAND FROM THE ISTHMUS OF TEHUANTEPEC
TO GUATEMALA TO THE YUCATAN PENINSULA.

...THE ITCZ...
15N17W 11N32W 10N37W 7N50W 7N63W. NUMEROUS STRONG THUNDERSTORMS
ARE FROM 8N TO 9N BETWEEN 24W AND 25W...FROM 9N TO 10N BETWEEN
25W AND 26.5W...AND FROM 8N TO 9.5N BETWEEN 40W AND 42W.
ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE
ELSEWHERE FROM 5N TO 15N BETWEEN AFRICA AND 53W.

DISCUSSION...

THE GULF OF MEXICO...THE CARIBBEAN SEA NORTH OF 18N WEST OF
THE WINDWARD PASSAGE...AND THE ATLANTIC OCEAN WEST OF 60W...
A DEEP LAYER TROUGH RUNS FROM A 30N78W MIDDLE TO UPPER LEVEL
CYCLONIC CIRCULATION CENTER TO A 27N87W GULF OF MEXICO MIDDLE
TO UPPER LEVEL CYCLONIC CIRCULATION CENTER. THE TROUGH CONTINUES
TO A SOUTHWESTERN GULF OF MEXICO CYCLONIC CENTER NEAR 22N92W.
A SURFACE TROUGH EXTENDS FROM 30N78W TO INLAND FLORIDA NEAR 29N
TO 29N84W IN THE GULF OF MEXICO WATERS...TO 26N87W TO 24N90W.
SCATTERED MODERATE SHOWERS TO ISOLATED/WIDELY SCATTERED STRONG
THUNDERSTORMS ARE ON THE SOUTH SIDE OF THE TROUGH FROM 20N TO
29N BETWEEN 74W AND 92W. THIS PRECIPITATION COVERS THE AREA FROM
THE NORTHWESTERN CARIBBEAN SEA TO THE SOUTHEASTERN GULF OF
MEXICO...TO THE BAHAMAS MOSTLY NORTH OF 23N. OTHER ISOLATED
LIGHT SHOWERS COVER THE BAHAMAS.

THE CARIBBEAN SEA...
THE 16N63W MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER
FROM 24 HOURS AGO IS NOT AS WELL-DEFINED NOW. IT APPEARS TO HAVE
WEAKENED...GIVING WAY TO A TROUGH ALONG 21N65W 18N66W 13N68W.
BROAD MIDDLE TO UPPER LEVEL CYCLONIC FLOW EXTENDS AS FAR TO THE
WEST AS 75W. MIDDLE TO UPPER LEVEL DRY AIR IS SUFFICIENT ENOUGH
IN ORDER TO SUPPRESS GREAT AMOUNTS OF SIGNIFICANT DEEP
CONVECTIVE PRECIPITATION. STRONG SHOWERS AND THUNDERSTORMS ARE
IN THE WATERS JUST OFF WEST CENTRAL HAITI. WARMING CLOUD TOP
TEMPERATURES AND DISSIPATING PRECIPITATION IN CENTRAL DOMINICAN
REPUBLIC AND IN THE MONA PASSAGE. A WEAK MIDDLE LEVEL CYCLONIC
CIRCULATION CENTER IS NEAR 16N80W. UPPER LEVEL WESTERLY WINDS
SOUTH OF 13N63W 14N70W 14N80W. IT APPEARS THAT A WEAK MIDDLE
LEVEL CYCLONIC CIRCULATION CENTER ALSO IS JUST SOUTH OF PANAMA
AND WEST OF COLOMBIA NEAR 7N79W. STRONG SHOWERS AND
THUNDERSTORMS DEVELOPED A FEW HOURS AGO FROM 11N TO 13N BETWEEN
72W AND 80W. THE CLOUD TOP TEMPERATURES IN SOME OF THE CELLS
HAVE BEEN WARMING...BUT IT IS LIKELY THAT PRECIPITATION STILL
IS FALLING IN THE WATERS OF THE SOUTH CENTRAL CARIBBEAN SEA.
SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS INLAND
IN PANAMA WITH THE ITCZ. STRONG SHOWERS AND THUNDERSTORMS ARE
IN WESTERN NICARAGUA/SOUTHERN HONDURAS/NORTH CENTRAL HONDURAS
IN AFTERNOON HEATING AND POSSIBLE ENERGY FROM THE TROPICAL WAVE
THAT PASSED THROUGH THIS AREA 24 HOURS AGO.

THE REST OF THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH PASSES THROUGH 31N44W TO 27N51W TO 25N60W
TO A CYCLONIC CIRCULATION CENTER NEAR 26N68W. THIS FEATURE
SUPPORTS A STATIONARY FRONT NORTH OF 31N...AND A SURFACE TROUGH
SOUTH OF 31N ALONG 31N40W 26N50W 25N57W 26N63W. ISOLATED
MODERATE SHOWERS ARE WITHIN 30 TO 45 NM ON EITHER SIDE OF 30N40W
26N50W 24N58W 26N63W 28N66W. A SURFACE RIDGE PASSES THROUGH
32N27W TO 26N38W TO 23N50W. THE 32N13W TO 29N16W MIDDLE TO UPPER
LEVEL TROUGH FROM 24 HOURS AGO HAS MOVED OVER MOROCCO. AN UPPER
LEVEL RIDGE IS ALONG 14N21W 23N25W BEYOND 32N26W. LARGE SCALE
UPPER LEVEL ANTICYCLONIC FLOW COVERS THE ATLANTIC OCEAN EAST OF
40W.

$$
MT




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