[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232257
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI OCT 23 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
2230 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS TILTED FROM 21N35W TO 14N37W MOVING NW NEAR 10
KT. WAVE IS AT THE LEADING EDGE OF A MAXIMUM IN TOTAL
PRECIPITABLE WATER WITH SATELLITE DERIVED WINDS SHOWING A
CYCLONIC CURVATURE ALONG THE WAVE AXIS. SCATTERED MODERATE/
STRONG CONVECTION IS FROM 15N-18N BETWEEN 32W-36W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION DOT THE REMAINDER
OF THE AREA FROM 14N-21N BETWEEN 34W-40W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N12W 8N20W 12N41W 10N57W
10N62W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE
WITHIN 120/150 NM ALONG THE COAST OF W AFRICA FROM 8N-12N.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N-7N
BETWEEN 10W-15W...FROM 7N-10N BETWEEN 23W-30W...AND FROM 2N-7N
BETWEEN 31W-40W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT CONTINUES TO MOVE ACROSS THE GULF AND AT 2100 UTC
ENTERS THE GULF OVER PENSACOLA FLORIDA THEN ALONG 25N90W THEN W
INTO MEXICO BETWEEN TAMPICO AND TUXPAN BECOMING STATIONARY ALONG
THE E SLOPES OF THE SIERRA MADRE MOUNTAINS. NARROW LINE OF
SCATTERED/HEAVY SHOWERS WITH ISOLATED THUNDERSTORMS IS WITHIN 30
NM OF LINE FROM 24N89W TO INLAND OVER N FLORIDA OVER APALACHEE
BAY CONTINUING OVER CENTRAL ALABAMA. THIS FRONT IS BEING
SUPPORTED BY A BROAD UPPER TROUGH WITH THE UPPER LOW MOVING N
OVER THE GREAT LAKES AREA AND DRY STABLE AIRMASS BEHIND THE
FRONT MAINLY OVER THE SE GULF COAST STATES. AN UPPER RIDGE
DOMINATES THE GULF WATERS ANCHORED N OF THE YUCATAN PENINSULA
NEAR 23N88W EXTENDING AN AXIS NE ACROSS THE FLORIDA PENINSULA
JUST N OF LAKE OKEECHOBEE. FRONT IS EXPECTED TO MOVE E EXTENDING
FROM NEAR TAMPA SW TO THE NE YUCATAN PENINSULA BY SAT EVENING
THEN GRADUALLY DISSIPATE OVER THE FAR SE WATERS SUN THROUGH MON.

CARIBBEAN SEA...
AN ILL-DEFINED 1008 MB LOW IS ANALYZED IN THE SW CARIBBEAN OFF
THE COAST OF NICARAGUA NEAR 13N83W AND IS EXPECTED TO DISSIPATE
OVER THE NEXT FEW HOURS BUT IS STILL GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN S OF 14N W
OF 78W TO INLAND OVER CENTRAL AMERICA. AN UPPER LOW IS CENTERED
BETWEEN CUBA AND JAMAICA COVERING THE CARIBBEAN W OF 70W TO THE
YUCATAN PENINSULA DRAWING DRY AIR AND STRONG SUBSIDENCE INTO THE
CENTRAL CARIBBEAN. HOWEVER THE UPPER LOW IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 17N-19N BETWEEN 77W-80W
INCLUDING PORTIONS OF JAMAICA. AN UPPER RIDGE IS ANCHORED OVER E
VENEZUELA COVERING THE E CARIBBEAN ACROSS THE LESSER ANTILLES
PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS FROM SOUTH AMERICA TO OVER THE
GREATER ANTILLES BETWEEN 69W-76W. THE REMAINDER OF THE CARIBBEAN
UNDER MOSTLY CLEAR SKIES THIS EVENING.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH COVERS THE W AND CENTRAL ATLC N OF 26N W
OF 35W SUPPORTING A SURFACE TROUGH THAT ENTERS THE REGION FROM A
COLD FRONT NEAR 32N32W ALONG 25N48W TO 23N65W WITH SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM EITHER
SIDE OF THE SURFACE TROUGH. STRONG SUBSIDENCE AND DRY STABLE AIR
ARE N OF THE 27N W OF 40W WITH A SURFACE RIDGE COVERING THE SAME
AREA ANCHORED BY A 1020 MB NEAR BERMUDA. E OF THE SURFACE TROUGH
IS A SECOND SURFACE RIDGE ANCHORED BY A 1021 MB HIGH OVER THE
SPAIN/PORTUGAL. IN THE TROPICAL ATLC...A 1009 MB LOW REMAINS N
OF THE ITCZ AND W OF THE TROPICAL WAVE NEAR 13N45W WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM
13N-16N BETWEEN 43W-47W.

$$
WALLACE



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