[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 14 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 61W S OF 15N MOVING W NEAR 15 KT. THE
WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP MOISTURE ACROSS THE
WINDWARD ISLANDS AND PORTIONS OF THE SE CARIBBEAN AS INDICATED
IN THE TOTAL PRECIPITABLE WATER IMAGERY. VISIBLE SATELLITE
IMAGERY SHOWS CYCLONIC CURVATURE IN THE LOW-LEVEL CLOUD FIELD IN
THE VICINITY OF THE WAVE AXIS. AS IT CONTINUES MOVING WWD INTO
THE SE CARIBBEAN AND A DRIER AND MORE STABLE ENVIRONMENT
ALOFT...ONLY A FEW ISOLATED SHOWERS ARE NOTED FROM 11N-14N
BETWEEN 60W-63W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N15W 8N28W 8N31W 9N48W 9N50W.
ONE SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 29W FROM
5N-11N. SCATTERED TO NUMEROUS MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 5N-12N BETWEEN 18W-34W. THIS ACTIVITY IS
LIKELY ENHANCED DUE TO AN UPPER LEVEL DIFFLUENT PATTERN ACROSS
THE ERN TROPICAL ATLC BETWEEN UPPER LEVEL TROUGHING N OF 13N AND
A BROAD UPPER LEVEL RIDGE OVER W AFRICA. A SECOND SURFACE
TROUGH...ALSO EMBEDDED WITHIN THE ITCZ...IS ANALYZED ALONG 49W
FROM 6N-14N. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM
5N-11N BETWEEN 46W-53W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD E-W ORIENTED UPPER LEVEL RIDGE EXTENDS ALONG 25N FROM
THE W ATLC...OVER THE FLORIDA PENINSULA...GULF OF MEXICO AND
ACROSS NRN MEXICO. AN UPPER LEVEL TROUGH CONTINUES PROGRESSING
OVER THE LOWER MISSISSIPPI RIVER VALLEY AND EXTENDS TROUGHING
ACROSS THE NW PORTION OF THE GULF. UPPER LEVEL DIFFLUENCE
BETWEEN THESE TWO UPPER LEVEL FEATURES IS GENERATING SCATTERED
SHOWERS AND ISOLATED TSTMS OVER THE NE GULF N OF 27W E OF 91W.
ELSEWHERE S OF 25N AND THE UPPER LEVEL RIDGE...DRY ELY FLOW
ALOFT COUPLED WITH A WEAK SURFACE PRESSURE GRADIENT IS PROVIDING
THE SRN GULF WITH GENERALLY CLEAR SKIES AND LIGHT E-SE WINDS.

CARIBBEAN SEA...
THE UPPER LEVEL ANTICYCLONIC CIRCULATION WITH AXIS ALONG 25N
OVER THE W ATLC AND GULF OF MEXICO IS PROVIDING MOST OF THE
CARIBBEAN WITH E-NE WINDS ALOFT N OF A SHEAR AXIS EXTENDING FROM
THE LESSER ANTILLES TO THE COAST OF NRN COLOMBIA NEAR 11N74W.
WATER VAPOR IMAGERY INDICATES AN OVERALL DRY AND STABLE
ATMOSPHERE IN THE MIDDLE TO UPPER LEVELS ACROSS THE ENTIRE BASIN
WITH ONLY A FEW AREAS OF ISOLATED SHOWERS MOVING WWD ON MODERATE
TRADE WINDS. A CONCENTRATED AREA OF THESE SHOWERS ARE FROM
16N-19N BETWEEN 75W-83W. IN THE SW CARIBBEAN...THE ITCZ AXIS
EXTENDS ALONG 9N ACROSS COSTA RICA AND PANAMA. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING S OF 11N.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N60W AND EXTENDS
SW ALONG 28N69W TO 28N78W. THE UPPER LEVEL TROUGH SUPPORTING
THIS FRONT IS QUICKLY MOVING EWD ACROSS THE NRN CENTRAL ATLC
WELL NORTH OF THE AREA. THE FRONT IS FORECAST TO GRADUALLY
DISSIPATE AND MERGE WITH A SECONDARY REINFORCING COLD FRONT THAT
ENTERS THE REGION NEAR 32N65W AND EXTENDS WWD ALONG 31N TO 80W.
ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE
SOUTHERNMOST FRONT. FARTHER E ACROSS THE ERN ATLC...A 1012 MB
SURFACE LOW IS CENTERED NEAR 29N32W WITH A SURFACE TROUGH
EXTENDING FROM 29N31W ALONG 25N34W TO 24N40W. ISOLATED SHOWERS
ARE WITHIN 30 NM EITHER SIDE OF THE SURFACE TROUGH WITH
SCATTERED SHOWERS LOCATED E OF THE LOW COVERING AN AREA FROM
26N-31N BETWEEN 23W-30W. THIS SURFACE LOW IS EMBEDDED BENEATH AN
UPPER LEVEL TROUGH AXIS ALONG 27W.

$$
HUFFMAN





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