[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN OCT 11 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2230 UTC.

...TROPICAL WAVES...

ATLANTIC TROPICAL WAVE EXTENDS FROM 17N40W TO 6N42W MOVING W
NEAR 10 KT. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS
INDICATE LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE
AXIS. THE WAVE ALSO LEADS A MAXIMUM IN DEEP LAYER MOISTURE
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION
IS CURRENTLY ASSOCIATED WITH THE WAVE. HOWEVER...ISOLATED
SHOWERS ARE FROM 11N-16N BETWEEN 40W-43W.

CARIBBEAN TROPICAL WAVE IS ALONG 78W S OF 18N MOVING W NEAR 15
KT. SATELLITE IMAGERY AS WELL AS AN ASCAT SCATTEROMETER PASS
FROM EARLIER TODAY INDICATE BROAD LOW-LEVEL CYCLONIC FLOW ACROSS
THE CENTRAL CARIBBEAN CONCENTRATED NEAR THE WAVE AXIS. THE WAVE
ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 10N-14N BETWEEN 78W-82W...AND FROM
17N-19N BETWEEN 76W-80W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 7N23W 10N32W 14N40W
6N58W. SCATTERED MODERATE CONVECTION IS ALONG THE AFRICA COAST
FROM 6N-8N BETWEEN 11W-14W. ISOLATED MODERATE CONVECTION IS FROM
10N-12N BETWEEN 12W-15W. SIMILAR ACTIVITY IS WITHIN 100 NM N OF
THE AXIS BETWEEN 44W-49W
...DISCUSSION...

THE GULF OF MEXICO...
AS OF 2100 UTC...A STATIONARY FRONT CROSSES N FLORIDA FROM NEAR
ST. AUGUSTINE AT 30N81W ENTERING THE GULF OF MEXICO NEAR 30N83W
CONTINUING TO 28N89W WHERE IT HAS BEGUN TO MOVE NWD AS A WARM
FRONT ALONG 28N95W 27N97W 23N97W INTO MEXICO TO 23N99W WHERE IT
AGAIN BECOMES STATIONARY ALONG THE E SLOPES OF THE SIERRA MADRE
MOUNTAINS. SCATTERED SHOWERS/THUNDERSTORMS ARE N OF 28N BETWEEN
88W-92W AFFECTING PORTIONS OF MISSISSIPPI AND LOUISIANA. SIMILAR
ACTIVITY IS ALSO OFF THE TEXAS COAST FROM 26N-28N BETWEEN
94W-96W...AND FROM 20N-24N BETWEEN 94W-97W OFF THE COAST OF
MEXICO. THE REMAINDER OF THE GULF IS EXPERIENCING GENERALLY FAIR
WEATHER THIS EVENING UNDER THE INFLUENCE OF MODERATELY DRY AIR
AND SUBSIDENCE ALOFT DUE TO AN UPPER LEVEL RIDGE CENTERED OVER
THE GULF OF MEXICO NEAR 26N86W. EXPECT A SURFACE RIDGE TO BUILD
ACROSS THE GULF AS THE FRONTAL SYSTEM CONTINUES TO LIFT NW
TONIGHT.

THE CARIBBEAN SEA...
A TROPICAL WAVE ALONG 78W IS THE MAIN SURFACE FEATURE ACROSS THE
CARIBBEAN. SEE ABOVE. A SURFACE TROUGH...REMNANTS OF
HENRI...EXTENDS ACROSS THE WINDWARD PASSAGE FROM 22N72W TO
18N74W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM OF THE
TROUGH AXIS AFFECTING WRN HISPANIOLA AND ERN CUBA. ISOLATED
SHOWERS/THUNDERSTORMS ARE ALSO N OF 16N BETWEEN 64W-70W. IN THE
UPPER LEVELS...DRY AIR AND SUBSIDENCE IN ELY FLOW ALOFT COVER
THE CARIBBEAN E OF 80W. AN UPPER LEVEL RIDGE EXTENDING FROM THE
GULF OF MEXICO COVERS THE BASIN W OF 80W. MODERATE WINDS ARE
ACROSS MUCH THE BASIN BECOMING FRESH IN THE SW AND ERN
CARIBBEAN. EXPECT THE TROPICAL WAVE ALONG 78W TO CONTINUE WWD.

THE ATLANTIC OCEAN...
A STATIONARY FRONT ENTERS THE AREA NEAR 31N77W CONTINUING TO THE
FLORIDA COAST NEAR ST AUGUSTINE CONTINUING INTO THE GULF OF
MEXICO. THE FRONT IS SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS
ACROSS THE FLORIDA PENINSULA N OF 26N. BROAD SURFACE HIGH
PRESSURE COVERS MUCH OF THE WRN BASIN ANCHORED BY A 1020 MB HIGH
NEAR 30N68W. THE SURFACE HIGH IS SUPPORTED BY AN UPPER LEVEL
RIDGE BETWEEN 40W-75W CENTERED NEAR 25N66W. A SURFACE
TROUGH...REMNANTS OF HENRI...IS THE FAR SW ATLC EXTENDING ACROSS
THE WINDWARD PASSAGE 22N72W TO 18N74W. MOST OF THE SHOWER
ACTIVITY ASSOCIATED WITH THE TROUGH IS S OF 21N IN THE
CARIBBEAN. A COLD FRONT ENTERS THE ERN ATLC NEAR 32N27W
EXTENDING ALONG 25N32W 21N40W 18N50W CONTINUING AS A SURFACE
TROUGH TO 19N64W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 200
NM BEHIND...AND 100 NM AHEAD OF THE FRONT N OF 23N. ISOLATED
SHOWERS ARE ALSO FROM 21N-26N BETWEEN 33W-36W...AND ALONG
THE SURFACE TROUGH BETWEEN 56W-64W. THE FRONTAL SYSTEM IS
SUPPORTED BY AN UPPER LEVEL TROUGH WITH AXIS ALONG 33W. AN UPPER
LEVEL RIDGE CENTERED NEAR 10N20W DOMINATES THE ERN TROPICAL ATLC.

$$
WALTON






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