[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130540
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED OCT 13 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS S OF THE CAPE VERDE ISLANDS FROM 15N23W TO
8N25W MOVING W NEAR 15 KT. WAVE IS WELL DEFINED IN THE GFS
STREAMLINES AND IN THE UPPER LEVEL SATELLITE WINDS. WAVE IS
ILL-DEFINED ON SATELLITE IMAGERY WITH A WEAK MOISTURE SURGE IN
AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. NO
ASSOCIATED CONVECTION IS NOTED.

TROPICAL WAVE WAS INTRODUCED ON THE 13/0000 UTC MAP ALONG
39W/40W S OF 14N. WAVE IS THE WESTERN EDGE OF AN UPPER RIDGE AND
AT THE LEADING EDGE OF A MOISTURE SURGE AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY.THE UPPER RIDGE IS ENHANCING CLUSTERS
OF SCATTERED MODERATE/STRONG CONVECTION FROM 8N-15N BETWEEN
33W-42W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST NEAR
17N16W. THE ITCZ EXTENDS FROM 8N31W S OF THE TROPICAL WAVE ALONG
9N41W 8N50W TO 8N57W. SCATTERED MODERATE/STRONG CONVECTION IS
WITHIN 200 NM ALONG THE COAST OF SW AFRICA BETWEEN 6N-11N.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 5N-9N BETWEEN 20W-34W. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE 6N-11N BETWEEN 42W-49W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH COVERS THE E HALF OF THE US CONUS INTO THE
GULF OF MEXICO N OF 27N WITH A SURFACE TROUGH ENTERING THE GULF
NEAR CEDAR KEY FLORIDA EXTENDING ALONG 26N87W TO 24N95W WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60
NM EITHER SIDE OF THE TROUGH AXIS. THIS UPPER TROUGH IS ALSO
SUPPORTING A COLD FRONT CURRENTLY OVER THE CENTRAL PLAIN STATES.
THIS UPPER TROUGH IS BRINGING DRY CONTINENTAL AIR OVER THE NW
GULF WITH ACCOMPANYING CLEAR SKIES N OF 26N W OF 87W AND A WEAK
1012 MB HIGH JUST OFF THE MISSISSIPPI DELTA. A BROAD UPPER RIDGE
DOMINATES THE S GULF ANCHORED OVER S MEXICO NEAR CIUDAD DEL
CARMEN. THE REMNANTS OF TROPICAL DEPRESSION TWELVE-E MADE
LANDFALL EARLIER THIS EVENING FROM THE E PACIFIC REGION NEAR THE
ISTHMUS OF TEHUANTEPEC GENERATING SCATTERED/HEAVY SHOWERS AND
SCATTERED THUNDERSTORMS OVER S MEXICO AND INTO THE BAY OF
CAMPECHE S OF 20N E OF 95W TO OVER THE YUCATAN PENINSULA. THE
SURFACE TROUGH WILL MOVE SLOWLY SE AND EXIT THE GULF ON THU
AHEAD OF A APPROACHING COLD FRONT. THIS COLD FRONT WILL MOVE
INTO THE NW GULF THU EXTENDING FROM TAMPA BAY TO THE BAY OF
CAMPECHE FRI THEN STALL ACROSS THE SE GULF THROUGH THE WEEKEND.
STRONG HIGH PRESSURE NW OF THE FRONT WILL COMBINE WITH BROAD LOW
PRESSURE THAT IS EXPECTED TO ENCOMPASS CENTRAL AMERICA FRI
THROUGH MON.

CARIBBEAN SEA...
THE UPPER RIDGE THAT DOMINATES THE S GULF OF MEXICO COVERS THE W
CARIBBEAN W OF 80W ENHANCING ISOLATED SHOWERS/THUNDERSTORMS IN
THE GULF OF HONDURAS FROM 17N-20N W OF 83W. AN ELONGATED UPPER
LOW EXTENDS FROM CUBA JUST E OF SANTIAGO DE CUBA JUST OFF THE E
TIP OF JAMAICA TO THE COAST OF COLOMBIA NEAR 11N74W GENERATING
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS BETWEEN
70W-78W WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS INLAND
AND WITHIN 75 NM ALONG THE COAST OF COLOMBIA. THE MONSOON TROUGH
REMAINS N EXTENDING FROM 12N74W 12N78W ACROSS CENTRAL AMERICA
AND INTO THE E PACIFIC REGION OVER NE NICARAGUA NEAR 14N84W WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF THE TROUGH W OF
81W TO INLAND OVER CENTRAL AMERICA. A LARGE UPPER TROUGH OVER
THE CENTRAL ATLC EXTENDS OVER THE FAR E CARIBBEAN GIVING THE
AREA MOSTLY FAIR WEATHER TONIGHT WITH SOME ISOLATED SHOWERS
USHERED IN ON THE EASTERLY SURFACE WINDS. A DEVELOPING BROAD LOW
PRESSURE IS EXPECTED ACROSS CENTRAL AMERICA AND THE W CARIBBEAN
TO THE FAR SW GULF OF MEXICO FRI THROUGH MON.

ATLANTIC OCEAN...
THE BROAD UPPER TROUGH THAT COVERS THE N GULF OF MEXICO EXTENDS
INTO THE W ATLC N OF 27N W OF 74W GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 75 NM ALONG THE COAST OF FLORIDA N
OF 26N. A WEAK SURFACE TROUGH REMAINS IN THE W ATLC EXTENDING
FROM 26N76W OVER THE TURKS AND CAICOS TO 21N72W WITH SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 23N-26N BETWEEN 70W-74W AND
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 26N
BETWEEN 68W-73W. A NARROW UPPER RIDGE IS TO THE E ALONG 67W
INDUCED BY A LARGE UPPER TROUGH THAT COVERS THE CENTRAL ATLC
EXTENDING THROUGH 32N47W ALONG 22N50W ACROSS THE W TROPICAL
ATLC/E CARIBBEAN TO 10N60W. A WEAK SURFACE TROUGH IS ANALYZED
WITHIN THIS UPPER TROUGH EXTENDING FROM 28N36W TO 23N46W
CONTINUING AS A SHEAR AXIS ALONG 22N51W TO 23N58W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 20N-22N BETWEEN 50W-52W
WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. SURFACE TROUGH
IN THE W ATLC WILL LIFT N AND DISSIPATE LATER TONIGHT. A COLD
FRONT WILL ENTER NW PORTION OF THE AREA THU AND EXTEND FROM
31N70W TO STRAITS OF FLORIDA SAT THEN BECOME NEARLY STATIONARY
AND WEAKEN SUN FROM BERMUDA TO STRAITS OF FLORIDA. HIGH PRES
WILL BUILD ACROSS W ATLC SAT NIGHT THROUGH MON.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW





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