[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 262342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON OCT 26 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
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 24W S OF 16N MOVING W NEAR 10 KT.
LOW-LEVEL CYCLONIC TURNING IS EVIDENT ON SATELLITE IMAGERY NEAR
THE WAVE AXIS. THE WAVE ALSO COINCIDES WITH A DEEP LAYER
MOISTURE MAXIMUM AS OBSERVED IN TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
8N-16N BETWEEN 19W-27W.

TROPICAL WAVE IS ALONG 55W S OF 17N MOVING W NEAR 15 KT. THE
WAVE LIES WITHIN A BROAD AREA OF DEEP LAYER MOISTURE BETWEEN
49W-59W AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP
CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE...HOWEVER...
ISOLATED SHOWERS ARE FROM 11N-17N BETWEEN 51W-57W AND ARE BEING
ENHANCED BY UPPER LEVEL DIFFLUENCE E OF AN UPPER LEVEL LOW
CENTERED OVER THE LEEWARD ISLANDS NEAR 17N60W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N15W 12N22W 11N25W 8N36W
11N53W 11N57W 10N63W. SCATTERED MODERATE TO STRONG CONVECTION IS
ALONG THE W AFRICA COAST FROM 7N-13N BETWEEN 9W-16W. CLUSTERS OF
SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION ARE FROM
1N-12N BETWEEN 38W-48W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A COLD FRONT EXTENDS INTO THE NW GULF NEAR SW
LOUISIANA ALONG 30N93W TO BROWNSVILLE TEXAS NEAR 26N97W AND INTO
INTERIOR NE MEXICO. LOW-LEVEL CONVERGENCE AND ATMOSPHERIC
INSTABILITY ARE FUELING NUMEROUS SHOWERS AND SCATTERED TSTMS
ALONG THE FRONT AND WITHIN 90/120 NM BEHIND THE FRONT...WITH
SCATTERED PRE-FRONTAL SHOWERS AND ISOLATED TSTMS ACROSS MUCH OF
THE CENTRAL GULF FROM 21N TO THE U.S. GULF COAST W OF 87W TO THE
FRONTAL BOUNDARY. THE COLD FRONT IS SUPPORTED ALOFT BY AN UPPER
LEVEL TROUGH THAT IS PROGRESSING ACROSS WEST TEXAS AND NORTHERN
MEXICO CURRENTLY AND CONTINUES TO PROVIDE AMPLE UPPER LEVEL
DIFFLUENCE ACROSS THE GULF THIS EVENING. AHEAD OF THE FRONT...
MOSTLY E-SE SURFACE WINDS UP TO 15 KT ARE OBSERVED WITH A
SURFACE TROUGH EXTENDING FROM THE YUCATAN PENINSULA TO 27N86W. A
FEW ISOLATED SHOWERS ARE WITHIN 120 NM OF THE SURFACE TROUGH.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE IS CENTERED OVER GUATEMALA NEAR 17N91W AND
CONTINUES TO PROVIDE DRY AIR AND SUBSIDENCE ALOFT OVER THE NW
CARIBBEAN W OF 84W AND OVER PORTIONS OF CENTRAL AMERICA.
HOWEVER...UPPER LEVEL DIFFLUENCE ON THE EASTERN PERIPHERY OF THE
UPPER LEVEL RIDGE IS GENERATING SCATTERED SHOWERS AND ISOLATED
TSTMS N OF 14N BETWEEN 78W-84W AND ACROSS PORTIONS OF CUBA. THIS
ACTIVITY EXTENDS S-SW ACROSS INTERIOR EASTERN HONDURAS...
NICARAGUA AND NORTHERN COSTA RICA. E OF 76W...AN UPPER LEVEL
TROUGH EXTENDS WESTWARD FROM AN UPPER LEVEL LOW CENTERED OVER
THE LEEWARD ISLANDS NEAR 17N60W. PRIMARILY DRY AIR ALOFT IS
NOTED ACROSS THE EASTERN CARIBBEAN ON WATER VAPOR IMAGERY.
MODERATE TRADE WINDS CONTINUE TO USHER IN ISOLATED LOW-LEVEL
SHOWERS E OF 74W THIS EVENING. ELSEWHERE...THE ITCZ AXIS EXTENDS
ACROSS PANAMA ALONG 8N AND IS GENERATING SCATTERED SHOWERS AND
ISOLATED TSTMS S OF 10N BETWEEN 77W-81W.

ATLANTIC OCEAN...
A DISSIPATING STATIONARY FRONT EXTENDS SW TO THE CENTRAL FLORIDA
PENINSULA FROM A 1013 MB LOW CENTERED NEAR 32N77W. LOW-LEVEL
CONVERGENCE NEAR THE BOUNDARY IS GENERATING ISOLATED SHOWERS
WITHIN 90 NM EITHER SIDE OF THE FRONT. THE REMAINDER OF THE W
ATLC IS CONTROLLED BY A BROAD SURFACE RIDGE ANCHORED BY A 1022
MB HIGH CENTERED NEAR 32N55W. THE SURFACE RIDGE IS SUPPORTED BY
A STRONG UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR
29N62W. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL RIDGE AND
AN UPPER LEVEL LOW CENTERED OVER THE LEEWARD ISLANDS NEAR 17N60W
IS SUPPORTING A SURFACE TROUGH ALONG 63W EXTENDING FROM 20N-25N.
ISOLATED SHOWERS COVER THE AREA FROM 19N-26N BETWEEN 60W-65W IN
THE VICINITY OF THE SURFACE TROUGH. FARTHER E...A COLD FRONT
ENTERS THE DISCUSSION AREA NEAR 32N23W EXTENDING SW ALONG 25N28W
TO 23N37W. ISOLATED SHOWERS ARE N OF 27N BETWEEN 18W-22W. THE
FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH REMAINING N OF
20N E OF 40W WITH AXIS ALONG 32N21W 25N27W TO 22N40W. AN UPPER
LEVEL RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC S OF 20N E
OF 40W. THIS UPPER RIDGE CONTINUES TO ENHANCE THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE ALONG 24W.

$$
HUFFMAN





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