[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 182342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE NOV 18 2008

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
2315 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 40W S OF 17N MOVING W AT 10-15 KT. A
NORTHWARD SURGE OF MOISTURE IS NOTED ON THE MIMIC-TPW PRODUCT
FROM CIMSS WITH BROAD CYCLONIC CURVATURE OBSERVED IN THE LOW-MID
LEVEL CLOUDS ALONG THE WAVE AXIS. SCATTERED MODERATE CONVECTION
REMAINS EMBEDDED WITHIN THE ITCZ FROM 8N-12N BETWEEN 36W-47W.

A TROPICAL WAVE IS ALONG 72W S OF 17N MOVING W 10-15 KT.
WELL-DEFINED CYCLONIC CURVATURE IS PRESENT IN SURFACE WIND
OBSERVATIONS IN THE VICINITY OF THE WAVE AXIS. SCATTERED SHOWERS
ARE FROM 13N-16N BETWEEN 68W-72W.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 8N12W 7N38W 8N42W 8N60W.
SCATTERED MODERATE CONVECTION IS FROM 5N-10N BETWEEN 31W-39W AND
FROM 9N-12N BETWEEN 42W-48W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 8N-11N BETWEEN 51W-54W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL TROUGH IS ACROSS THE ERN CONUS WITH UPPER
CYCLONIC FLOW AND DRY AIR IN SUBSIDENCE COVERING THE GULF N OF
23N. UPPER LEVEL ANTICYCLONIC FLOW IS MOVING FROM THE ERN
PACIFIC OCEAN ACROSS MEXICO INTO THE GULF OF MEXICO S OF 23N. A
SHORTWAVE TROUGH IS MOVING THROUGH THE SE CONUS AND IS
SUPPORTING A SECONDARY COLD FRONT THAT EXTENDS FROM THE W ATLC
ACROSS CENTRAL FLORIDA THROUGH MELBOURNE AND CLEARWATER W TO
29N90W IN THE N/CENTRAL GULF AND INLAND ACROSS TEXAS NEAR
GALVESTON. SCATTERED STRATOCUMULUS CLOUDS ARE MAINLY S OF 26N
ACROSS THE GULF THIS EVENING.

CARIBBEAN SEA...
A SURFACE STATIONARY FRONT EXTENDS FROM ERN CUBA NEAR 21N76W SW
TO 17N80W AND INLAND ACROSS SRN NICARAGUA NEAR 12N84W. LOW-LEVEL
CONVERGENCE NEAR THIS FRONT IS INTERACTING WITH DEEP MOISTURE
OVER THE WRN CARIBBEAN GENERATING SCATTERED SHOWERS AND TSTMS S
OF 17N AND W OF 78W. THIS ACTIVITY IS BEING ENHANCED BY UPPER
LEVEL DIVERGENCE IN THE VICINITY OF AN UPPER RIDGE PRESENT OVER
THE W CARIBBEAN WITH THE AXIS EXTENDING FROM NRN VENEZUELA TO
15N75W W TO ACROSS SRN MEXICO. OVER THE ERN CARIBBEAN...UPPER
LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS ACROSS THE SE
CARIBBEAN S OF 15N AND E OF 69W.

ATLANTIC OCEAN...
A BROAD UPPER TROUGH IS OVER THE ERN CONUS AND THE W ATLC...
WHICH IS SUPPORTING A SURFACE STATIONARY FRONT THAT EXTENDS FROM
ERN CUBA NEAR 21N76W ACROSS THE SE BAHAMAS TO BEYOND 32N61W.
SCATTERED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THIS BOUNDARY.
TO THE W OF THIS STATIONARY FRONT...A SECONDARY COLD FRONT
ENTERS THE DISCUSSION AREA NEAR 32N70W AND EXTENDS SW TO NEAR
MELBOURNE FLORIDA. SCATTERED STRATOCUMULUS CLOUDS COVER THE W
ATLC N OF 27N AND W OF THE COLD FRONT. A 1016 MB SURFACE HIGH IS
CENTERED NEAR 26N56W WHICH IS SUPPORTED BY AN UPPER LEVEL RIDGE
WITH AXIS EXTENDING NE FROM PUERTO RICO TO BEYOND 32N54W. ACROSS
THE E/CENTRAL ATLC AN UPPER LOW IS CENTERED NEAR 32N39W THAT IS
ACCOMPANIED BY UPPER TROUGHING N OF 24N BETWEEN 25W-40W. THE
UPPER LOW SUPPORTS A PAIR OF SURFACE LOWS...A 1006 MB LOW
CENTERED NEAR 32N47W AND A 1007 MB LOW CENTERED NEAR 32N41W.
SCATTERED SHOWERS ARE FROM 28N-32N BETWEEN 35W-39W. A SURFACE
TROUGH EXTENDS FROM 32N33W TO 26N31W TO 19N37W...WITH SCATTERED
SHOWERS N OF 22N BETWEEN 27W-32W. THIS ACTIVITY IS BEING
ENHANCED BY UPPER LEVEL DIFFLUENCE IN SOUTHWESTERLY FLOW ALOFT
BETWEEN THE ACCOMPANYING UPPER TROUGH AND AN UPPER RIDGE N OF
24N WITH AXIS ALONG 22W. OVER THE TROPICAL ATLC...AN UPPER RIDGE
IS S OF 20N BETWEEN THE AFRICAN COAST AND 25W...WITH ANOTHER
UPPER RIDGE PRESENT S OF 8N BETWEEN 25W-42W. UPPER LEVEL
DIFFLUENCE NEAR THESE UPPER FEATURES IS ENHANCING THE ACTIVITY
CONVECTION ASSOCIATED WITH THE ITCZ.

$$
HUFFMAN


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