[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 031726
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 03 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
1645 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 30W/31W S OF 13N MOVING W 10-15 KT. LOW
AMPLITUDE WAVE EMBEDDED WITHIN THE ITCZ AND WITHIN A BROAD SWATH
OF DEEP LAYER MOISTURE THAT COVERS THE TROPICS FROM 23W-40W AS
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. VERY LITTLE
CYCLONIC TURNING CAN BE OBSERVED IN THE VISIBLE SATELLITE
IMAGERY. SCATTERED MODERATE CONVECTION IS TO THE W OF THE WAVE
AXIS FROM 9N-14N BETWEEN 31W-36W.

TROPICAL WAVE IS ALONG 47W/48W S OF 15N MOVING W NEAR 15 KT.
WELL DEFINED LOW AMPLITUDE WAVE THAT HAS BEEN TRACKED ACROSS THE
ATLC WITH A LOW LEVEL CYCLONIC CURVATURE ALONG THE WAVE AXIS.
WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM AS
INDICATED IN TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 8N-14N
BETWEEN 44W-50W.

TROPICAL WAVE IS ALONG 69W S OF 18N MOVING W NEAR 10 KT.
ILL-DEFINED WAVE JUST TO THE E OF A SHARP UPPER TROUGH AND UPPER
LOW. WAVE IS ALSO EMBEDDED WITHIN AN AREA OF SLIGHT MOISTURE AS
INDICATED IN TOTAL PRECIPITABLE WATER IMAGERY. NO ASSOCIATED
SHOWERS/CONVECTION.


...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N14W 7N23W 9N33W 8N39W 9N47W
8N55W 10N65W. SCATTERED CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM 5N-8N BETWEEN 30W-43W. SCATTERED
MODERATE CONVECTION IS FROM 5N-9N BETWEEN 25W-30W.

...DISCUSSION...

GULF OF MEXICO...
STATIONARY FRONT EXTENDS ACROSS THE N GULF ENTERING THE AREA
BETWEEN PANAMA CITY AND PENSACOLA FLORIDA SW ACROSS THE
MISSISSIPPI DELTA OF LOUISIANA TO ACROSS S TEXAS NEAR CORPUS
CHRISTI. THE FRONT CONTINUES TO BE SUPPORTED BY A LARGE UPPER
LEVEL TROUGH THAT IS MOVING ACROSS THE FLORIDA PENINSULA. A
BROAD UPPER RIDGE ANCHORED OVER CENTRAL MEXICO EXTENDS ACROSS
THE GULF BETWEEN TUXPAN AND TAMPICO TO S FLORIDA PROVIDING
DIFFLUENCE ALOFT TO ENHANCE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS MOVING OFF TEXAS TO N OF 28N W OF 92W. ISOLATED
SHOWERS ARE WITHIN 60 NM ALONG THE COAST OF MEXICO FROM TAMPICO
TO TUXPAN. THE AREA BETWEEN THE UPPER LEVEL FEATURES MENTIONED
ABOVE IS GIVING THE GULF STRONG UPPER LEVEL WINDS AND ALTHOUGH
THE UPPER RIDGE IS DRAWING TROPICAL MOISTURE OVER THE GULF ONLY
ISOLATED SHOWERS ARE FROM 24N-28N BETWEEN 85W-94W.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH COVERS MOST OF THE W CARIBBEAN CENTERED BY
AN UPPER LOW NEAR 16N76W AND COMBINED WITH THE UPPER RIDGE OVER
THE GULF OF MEXICO CONTINUES TO USHER IN DRY STABLE AIR BETWEEN
80W-84W. THE UPPER LEVEL TROUGH IS GENERATING CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 19N TO INLAND OVER
COLOMBIA AND PANAMA BETWEEN 72W-80W. AN UPPER RIDGE IS OVER THE
E CARIBBEAN ALONG 66W PROVIDING DIFFLUENCE ALOFT TO GENERATE
SCATTERED MODERATE/ISOLATED STRONG CONVECTION S OF 15N TO INLAND
OVER VENEZUELA BETWEEN 66W-70W. MOSTLY CLEAR SKIES PREVAIL OVER
THE NW CARIBBEAN N OF 15N W OF 80W AND ACROSS THE E CARIBBEAN E
OF 65W ACROSS THE LESSER ANTILLES.

ATLANTIC OCEAN...
THE UPPER TROUGH THAT EXTENDS OVER THE FLORIDA PENINSULA COVERS
THE W ATLC N OF 26W W OF 76W SUPPORTING A WEAK SURFACE TROUGH
THAT EXTENDS FROM THE UPPER FLORIDA KEYS NEAR 25N80.5W OFF THE E
COAST OF FLORIDA TO 29N79W. A BROAD UPPER RIDGE COVERS THE
REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC ANCHORED NEAR
24N65W PROVIDING DIFFLUENCE ALOFT TO GENERATE A LARGE AREA OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 20N-23N BETWEEN
67W-71W...FROM 21N-28N BETWEEN 71W-76W...AND N OF 28N TO BEYOND
32N BETWEEN 67W-78W. A SURFACE TROUGH EXTENDS FROM 21N55W
THROUGH A WEAKENING 1014 MB LOW NEAR 17N56W TO 13N56W GENERATING
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM
14N-21N BETWEEN 53W-58W. AN UPPER TROUGH IS OVER THE NE ATLC
EXTENDING A REMNANT SURFACE TROUGH INTO THE REGION NEAR 32N21W
SW ALONG 28N37W 28N50W TO 27N54W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE TROUGH N OF
30N...WITHIN 120/150 NM S OF THE TROUGH FROM 27W-42W...AND N OF
23N FROM 42W-52W. THE TYPICAL E/W UPPER RIDGE DOMINATES MUCH OF
THE TROPICS WITH THE AXIS EXTENDING ALONG 11N/12N TO 50W
ENHANCING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES AND
THE ITCZ. WEAK SURFACE RIDGE CUTS A SWATH ACROSS THE REGION
BETWEEN 20N-25N WITH A 1020 MB HIGH NEAR 25N253W.

$$
WALLACE





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