[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON OCT 05 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH WWW UTC.

...TROPICAL WAVES...

ACTIVE TROPICAL WAVE IS ALONG 42W S OF 15N MOVING W 15-20 KT.
SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE A BROAD
AREA OF LOW/MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE
AXIS. A 2342 UTC ASCAT SCATTEROMETER PASS ALSO DENOTES A
LOW-LEVEL SE-NE WIND SHIFT. THE WAVE ALSO COINCIDES WITH A DEEP
LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED STRONG CONVECTION IS FROM 13N-16N BETWEEN
40W-45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
9N-13N BETWEEN 40W-48W. THIS ACTIVITY IS ENHANCED BY DIFFLUENT
FLOW ALOFT.

TROPICAL WAVE IS ALONG 57W S OF 15N MOVING W NEAR 15 KT. THE
WAVE COINCIDES WITH A LOW AMPLITUDE DEEP LAYER MOISTURE MAXIMUM
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-13N BETWEEN
52W-58W. THIS ACTIVITY IS ENHANCED BY DIFFLUENT FLOW ALOFT.

TROPICAL WAVE IS ALONG 79W S OF 17N MOVING W 10-15 KT. THE WAVE
LIES WITHIN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. MOST OF THE ASSOCIATED SHOWERS
HAVE NOW DISSIPATED. HOWEVER A FEW ISOLATED SHOWERS AND
THUNDERSTORMS REMAIN NEAR 15N78W...AND S OF 12N W OF 80W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N20W 8N30W 9N41W
8N62W.SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
7N-9N BETWEEN 11W-13W. ISOLATED MODERATE/STRONG CONVECTION IS
WITHIN 50 NM OF THE AXIS BETWEEN 22W-28W. SIMILAR ACTIVITY IS
FROM 5N-7N BETWEEN 32W-37W.

...DISCUSSION...

THE GULF OF MEXICO...
A WARM FRONT EXTENDS ACROSS THE FLORIDA PANHANDLE FROM NEAR
30N81W TO 32N89W CONTINUING AS A STATIONARY FRONT TO A 1007 MB
SURFACE LOW OVER LOUISIANA NEAR 31N92W EXTENDING ACROSS TEXAS TO
NEAR 30N102W. SURFACE CONVERGENCE NEAR THIS FRONT/LOW IS
GENERATING SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS N OF 29N W
OF 89W...AND ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS N OF 28N
BETWEEN 82W-89W. THE REMAINDER OF THE GULF IS GENERALLY CALM
UNDER THE INFLUENCE OF A WEAK SURFACE RIDGE BUILDING ALONG 25N.
LOW-LEVEL ANTICYCLONIC FLOW IS AROUND THE RIDGE WITH WINDS
REACHING UP TO 20 KT IN THE WRN GULF. IN THE UPPER LEVELS...AN
UPPER LEVEL RIDGE COVERS THE BASIN CENTERED OVER THE SW GULF
NEAR 22N95W. EXPECT THE SURFACE RIDGE TO PERSIST OVER THE NEXT
FEW DAYS.

THE CARIBBEAN SEA...
MODERATELY DRY AIR ALOFT IN ASSOCIATION WITH AN UPPER LEVEL
RIDGE COVERING THE NW CARIBBEAN EXTENDING FROM THE GULF OF
MEXICO IS SUPPORTING GENERALLY FAIR WEATHER ACROSS THE NW
PORTION OF THE BASIN. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE
NEAR A TROPICAL WAVE ALONG 79W...SEE ABOVE. AN UPPER LEVEL
TROUGH EXTENDING FROM THE ATLC ACROSS THE WINDWARD PASSAGE TO
NEAR 10N80W IS ENHANCING ISOLATED SHOWERS ACROSS THE CENTRAL
CARIBBEAN BETWEEN 66W-76W. A SURFACE TROUGH EXTENDS ACROSS THE
LEEWARD ISLANDS FROM 20N64W TO 14N62W SUPPORTING ISOLATED
SHOWERS/THUNDERSTORMS N OF 15N BETWEEN 61W-64W. MODERATE TO
FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN. EXPECT A TROPICAL
WAVE CURRENTLY ALONG 57W TO REACH THE E CARIBBEAN LATER TODAY.

THE ATLANTIC OCEAN...
A DYING COLD FRONT CLIPS THE FAR W ATLC FROM 32N72W TO 30N79W.
NO SHOWERS ARE CURRENTLY ASSOCIATED WITH THE FRONT. A SURFACE
TROUGH EXTENDS FROM 31N69W TO 27N73W SUPPORTING A CLUSTER OF
SHOWERS/THUNDERSTORMS FROM 30N-31N BETWEEN 66W-68W. THIS SURFACE
TROUGH IS SUPPORTED BY AN UPPER LEVEL TROUGH W AXIS FROM 32N67W
TO THE WINDWARD PASSAGE NEAR 20N74W. AN UPPER LEVEL RIDGE COVERS
THE AREA W OF THE UPPER TROUGH EXTENDING FROM THE GULF OF
MEXICO. A SECOND UPPER LEVEL RIDGE IS THE E WITH AXIS ALONG 60W.
THE REMAINDER OF THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED BY A 1019 MB SURFACE HIGH NEAR 27N65W...AND A 1020 MB
SURFACE HIGH NEAR 34N52W. ELSEWHERE IN THE UPPER LEVELS...AN
UPPER LEVEL TROUGH IS N OF 17N BETWEEN 45W-56W CENTERED NEAR
28N52W. A BROAD UPPER LEVEL RIDGE DOMINATES THE REMAINDER OF THE
BASIN CENTERED NEAR 15N26W. BROAD UPPER DIFFLUENT FLOW AROUND
THE E SIDE OF THIS RIDGE IS ENHANCING CONVECTION NEAR THE
TROPICAL WAVES IN THE ATLC.

$$
WALTON





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