[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251019
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT OCT 25 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0945 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 25W S OF 13N MOVING W 10-15 KT. WAVE IS
EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE WITH CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 5N-12N
BETWEEN 21W-27W.

TROPICAL WAVE IS ALONG 36W/37W S OF 12N MOVING W 10-15 KT. WAVE
IS BENEATH AN UPPER LOW AND IS EMBEDDED WITHIN DRY AIR WHICH IS
LIMITING ANY SHOWERS/DEEP CONVECTION.

TROPICAL WAVE IS ALONG 59W S OF 18N MOVING W NEAR 5 KT. WAVE HAS
MOVED INTO AN AREA OF STRONG SUBSIDENCE AND DRY/STABLE AIR THUS
LIMITING ANY SHOWERS/DEEP CONVECTION.

...THE ITCZ...
ITCZ AXIS IS ANALYZED ALONG 10N12W 8N18W 6N44W 10N58W. SCATTERED
MODERATE/STRONG CONVECTION IS 75/90 NM OF THE ITCZ FROM 29W-32W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVER
THE REMAINDER OF THE AREA FROM THE EQUATOR TO 13N BETWEEN
24W-34W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH IS MOVING OFF THE E US INTO THE W ATLC
WHILE THE GULF WATERS ARE DOMINATED BY AN UPPER RIDGE ANCHORED
IN THE NW CARIBBEAN. A WEAK COLD FRONT EXTENDS OVER FLORIDA FROM
JUST W OF JACKSONVILLE INTO THE GULF NEAR CEDAR KEY TO 26N85W
CONTINUING AS A STATIONARY FRONT TO 22N89W WHICH IS JUST W OF A
1012 MB LOW OFF THE NE COAST OF THE YUCATAN NEAR 22N87W. DENSE
CLOUD COVER WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE E OF THE FRONTAL BOUNDARY ACROSS THE FLORIDA
PENINSULA AND THROUGH THE FLORIDA STRAITS. THE UPPER RIDGE IS
DRAWING UPPER MOSITURE FROM THE E PACIFIC ACROSS MEXICO TO OVER
THE W GULF MOSTLY IN THE FORM OF HIGH CLOUDS. THE FRONT IS
EXPECTED TO CLEAR THE GULF LATE SUN/EARLY MON.

CARIBBEAN SEA...
BROAD UPPER RIDGE COVERS MOST OF THE CARIBBEAN ANCHORED JUST W
OF THE CAYMAN ISLANDS EXTENDING OVER THE GULF OF MEXICO AND INTO
THE W ATLC. AN UPPER TROUGH EXTENDS INTO THE FAR E CARIBBEAN
ACROSS THE LESSER ANTILLES NEAR MARTINIQUE TO THE ABC ISLANDS.
UPPER DIFFLUENCE IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER THE NW CARIBBEAN N OF 21N W OF 77W TO OVER
CUBA AND THE YUCATAN AND OVER THE S CARIBBEAN S OF A LINE FROM
COLOMBIA NEAR 11N73W TO THE GULF OF HONDURAS NEAR 17N86W. THE
REMAINDER OF THE CARIBBEAN IS UNDER STRONG SUBSIDENCE AND DRY
STABLE WITH POSSIBLE ISOLATED LOW LEVEL SHOWERS USHERED IN ON
MODERATE EASTERLY TRADE WINDS MAINLY OVER THE ABC ISLANDS.

ATLANTIC OCEAN...
THE BROAD UPPER RIDGE ANCHORED IN THE NW CARIBBEAN EXTENDS
ACROSS THE W ATLC W OF 60W AND PROVIDING UPPER DIFFLUENCE TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 150 NM
OF LINE FROM CUBA NEAR 23N80W TO BEYOND 32N74W WITH GALE FORCE
WINDS N OF 28N W OF 75W. A NARROWING DEEP LAYERED TROUGH EXTENDS
INTO THE CENTRAL ATLC NEAR 32N52W ALONG 23N52W THEN SW INTO THE
E CARIBBEAN ACROSS THE LESSER ANTILLES NEAR MARTINIQUE. THE
ASSOCIATED COLD FRONT ENTERS THE REGION NEAR 32N46W EXTENDING
ALONG 26N52W TO 22N61W WHERE IT CONTINUES AS A STATIONARY
BOUNDARY TO E OF THE TURKS AND CAICOS NEAR 22N68W. A PRE-FRONTAL
SURFACE TROUGH EXTENDS FROM 25N51W TO 17N55W. A LOWER LEVEL
SWIRL IS ALONG THIS TROUGH NEAR 19N. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 200 NM E OF THE FRONT N OF 24N. A
SURFACE RIDGE HAS BRIDGED THE FRONT WITH A RIDGE AXIS EXTENDING
S TO BERMUDA THEN SW ACROSS THE BAHAMAS TO 22N77W AND ANCHORED
BY A 1030 MB HIGH OFF THE NEW ENGLAND COAST. A NARROW UPPER
RIDGE IS JUST TO THE E OF THE UPPER TROUGH ENHANCING THE ABOVE
ACTIVITY. A CUT OFF UPPER LOW IS IN THE E ATLC NEAR 19N33W
AMPLIFYING AN UPPER RIDGE TO THE E TO 24N E OF 25W. A SECOND
SURFACE RIDGE COVERS THE E ATLC N OF 17N E OF 42W ANCHORED BY A
1031 MB HIGH E OF THE AZORES.

$$
WALLACE



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