[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 012318
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU OCT 01 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
2245 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 36W S OF 13N MOVING W NEAR 15 KT. THE
WAVE COINCIDES WITH A SLIGHT MAXIMUM IN DEEP LAYER MOISTURE
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE REMAINS
LOW-AMPLITUDE BUT SATELLITE IMAGERY DOES INDICATE SOME CYCLONIC
FLOW IN THE VICINITY OF THE WAVE AXIS. ISOLATED MODERATE/STRONG
CONVECTION IS FROM 10N-12N BETWEEN 36W-40W.

TROPICAL WAVE IS ALONG 53W S OF 20N MOVING WNW NEAR 15 KT. THE
WAVE LEADS A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY AND SATELLITE
DERIVED WINDS INDICATE LOW-LEVEL CYCLONIC TURNING AROUND THE
WAVE AXIS. THE WAVE LIES UNDERNEATH THE AXIS OF AN UPPER LEVEL
TROUGH. DIFFLUENT FLOW ALOFT AROUND THE E SIDE OF THE UPPER
TROUGH IS ENHANCING SCATTERED STRONG CONVECTION E OF THE WAVE
AXIS FROM 11N-16N BETWEEN 46W-50W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N13W 6N20W 8N34W 7N43W 12N51W
10N66W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
5N-8N BETWEEN 17W-19W. SIMILAR CONVECTION IS FROM 4N-10N BETWEEN
21W-29W.

...DISCUSSION...

GULF OF MEXICO...
THE TAIL END OF A DYING STATIONARY FRONT EXTENDS ACROSS S
FLORIDA INTO THE FAR SE GULF OF MEXICO ALONG 25N BETWEEN
80W-85W. A FEW ISOLATED SHOWERS REMAIN ACROSS THE STRAITS OF
FLORIDA E OF 82W. A FEW ISOLATED SHOWERS ARE IN THE FAR NW GULF
N OF 29N W OF 93W AHEAD OF A COLD FRONT OVER NRN TEXAS. THE
REMAINDER OF THE GULF IS CALM AND CLEAR TONIGHT UNDER STRONG
SUBSIDENCE AND STABLE DRY AIR ALOFT. AN UPPER LEVEL RIDGE COVERS
THE BASIN CENTERED OVER MEXICO NEAR 22N105W. SE TO S WINDS FLOW
OVER THE WRN GULF UP TO 20 KT IN THE FAR NW GULF. EXPECT THE
BASIN TO REMAIN UNDER CLEAR CONDITIONS BEFORE THE COLD FRONT
CURRENTLY OVER TEXAS APPROACHES THE NW WATERS TOMORROW.

CARIBBEAN SEA...
SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE NRN CARIBBEAN
TONIGHT N OF 19N BETWEEN 76W-83W INCLUDING MOST OF CUBA. THIS
ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE AROUND AN UPPER
LEVEL TROUGH THAT EXTENDS OVER THE E FLORIDA COAST ACROSS CUBA
AND OVER THE WRN CARIBBEAN TO NEAR 15N83W. THIS DIFFLUENT FLOW
ALOFT IS ALSO SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OVER
HISPANIOLA N OF 18N BETWEEN 69W-72W. ISOLATED
SHOWERS/THUNDERSTORMS ARE IN THE SW CARIBBEAN S OF 11N BETWEEN
77W-83W DUE TO SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ. THE
REMAINDER OF THE CARIBBEAN IS EXPERIENCING CLEAR WEATHER UNDER
MODERATELY DRY AIR ALOFT. MODERATE TO FRESH TRADEWINDS ARE
ACROSS MUCH OF THE BASIN BECOMING STRONG IN THE SW CARIBBEAN AND
NEAR THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N61W TO 27N71W
CONTINUING AS A STATIONARY FRONT TO S FLORIDA NEAR MIAMI AT
26N80W. SCATTERED SHOWERS/THUNDERSTORMS ARE AHEAD OF THE FRONT S
OF 26N BETWEEN 73W-78W. A FEW ISOLATED SHOWERS ARE ALSO WITHIN
150 NM ELSEWHERE ALONG THE FRONT. THE FRONT IS SUPPORTED BY AN
UPPER LEVEL TROUGH EXTENDING OVER THE E COAST OF FLORIDA AND
INTO THE WRN CARIBBEAN. THIS UPPER TROUGH IS ALSO SUPPORTING
ISOLATED SHOWERS N OF 25N BETWEEN 47W-60W. A 1018 MB SURFACE
HIGH IS NEAR 25N61W. A SURFACE TROUGH IS E OF THE LEEWARD
ISLANDS FROM 20N59W TO 14N61W. A FEW ISOLATED SHOWERS ARE ALONG
THE TROUGH AXIS. A DYING COLD FRONT CLIPS THE AREA FROM 32N28W
TO 32N42W. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 31N23W TO
28N43W. ISOLATED SHOWERS ARE ALONG THE TROUGH AXIS. A 1020 MB
HIGH IS IN THE FAR NE ATLC NEAR 31N13W. IN THE UPPER LEVELS...AN
UPPER LEVEL RIDGE IS BETWEEN 53W-65W. AN UPPER LEVEL LOW IS NEAR
25N48W EMBEDDED IN A LARGER UPPER LEVEL TROUGH TO THE N WHICH IS
SUPPORTING THE DYING COLD FRONT IN THE CENTRAL ATLC. ANOTHER
UPPER LEVEL TROUGH COVERS THE ERN CARIBBEAN. UPPER DIFFLUENT
FLOW ON THE E SIDE OF THIS UPPER TROUGH IS SUPPORTING CLOUDINESS
AND POSSIBLE SHOWERS N OF 16N BETWEEN 22W-27W.

$$
WALTON






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