[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202323
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE OCT 20 2015

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 14N17W ALONG 12N19W TO A WEAK 1011 MB LOW NEAR 10N34W
TO A SECOND 1011 MB LOW NEAR 10N41W TO 9N43W WHERE THE ITCZ
BEGINS AND CONTINUES ALONG 8N48W TO 10N54W. A SURFACE TROUGH IS
THE W OF THE ITCZ EXTENDING FROM 14N53W TO 9N57W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N-13N
BETWEEN 19W-30W...FROM 7N-12N BETWEEN 39W-44W...AND FROM 9N-11N
BETWEEN 53W-56W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS THE GULF TO OVER THE E CONUS ANCHORED
IN THE E PACIFIC REGION S OF THE GULF OF TEHUANTEPEC. A SHALLOW
SURFACE TROUGH EXTENDS FROM 26N93W TO THE E BAY OF CAMPECHE NEAR
19N92W. REMNANT MOISTURE ASSOCIATED WITH THE RECENT FRONTAL
PASSAGE IS STILL GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS FROM 22N-25N E OF THE SURFACE TROUGH TO
OVER W CUBA AND THROUGH THE STRAITS OF FLORIDA. A STRONG SURFACE
RIDGE COVERS THE GULF ANCHORED BY A 1029 MB HIGH OVER SOUTH
CAROLINA. THE SOUTHERLY RETURN FLOW ALONG THE SW LOUISIANA/E
TEXAS COAST IS GENERATING ISOLATED SHOWERS N OF 28N BETWEEN 93W-
96W. THIS IS LEAVING THE REMAINDER OF THE GULF WITH FAIR WEATHER
THIS EVENING. THE TIGHT PRESSURE GRADIENT BETWEEN THE SURFACE
RIDGE AND LOWER PRESSURE OVER THE YUCATAN PENINSULA WILL
MAINTAIN STRONG E WINDS ACROSS THE E/CENTRAL GULF THROUGH EARLY
WED THEN WILL RELAX LATER ON WED.

CARIBBEAN SEA...
A BROAD UPPER RIDGE THAT DOMINATES THE GULF OF MEXICO COVERS THE
CARIBBEAN W OF 73W. AN ELONGATED UPPER LOW IS CENTERED ALONG THE
COAST OF VENEZUELA NEAR 10N65W WITH A TROUGH AXIS EXTENDING E-NE
ACROSS THE WINDWARD ISLANDS NEAR 13N61W INTO THE W TROPICAL ATLC
AND COVERS THE REMAINDER OF THE CARIBBEAN. A SHALLOW SURFACE
TROUGH IS BENEATH THE UPPER RIDGE OVER THE YUCATAN PENINSULA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE INLAND OVER THE
YUCATAN WITH ISOLATED SHOWERS IN THE GULF OF HONDURAS S OF 18N W
OF 87W. A FRONTAL BOUNDARY N OF THE GREATER ANTILLES IS
PROVIDING MOISTURE AND INSTABILITY TO GENERATE SCATTERED TO
NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS N OF 18N BETWEEN 69W-81W
WITH EVENING THUNDERSTORMS OVER PUERTO RICO AND JAMAICA. THIS IS
LEAVING THE REMAINDER OF THE CARIBBEAN WITH FAIR WEATHER THIS
EVENING. THE WEAKENING FRONTAL BOUNDARY WILL MOVE OVER THE
GREATER ANTILLES THU INTO FRI. THE SURFACE TROUGH IN THE W
TROPICAL ATLC WILL ENTER THE SE CARIBBEAN WED NIGHT AND THU THEN
DISSIPATE FRI.

...HISPANIOLA...
CURRENTLY SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS
ARE ACROSS THE ISLAND THIS EVENING. THE FRONTAL BOUNDARY N OF
THE ISLAND IS PROVIDING MOISTURE AND INSTABILITY TO GENERATE THE
ABOVE ACTIVITY. THE FRONT IS EXPECTED TO CONTINUE SE TONIGHT
STALLING ACROSS THE GREATER ANTILLES WED. A WEAK LOW WILL
DEVELOP ALONG THE FRONT E OF THE TURKS AND CAICOS ON THU AND
RACE NE DRAGGING THE FRONT E ON FRI. THIS WILL KEEP THE MOISTURE
AND INSTABILITY ACROSS THE ISLAND TO CONTINUE SHOWERS/
THUNDERSTORMS THROUGH THE END OF THE WEEK.

ATLANTIC OCEAN...
A STRONG UPPER TROUGH COVERS THE W ATLC SUPPORTING A COLD FRONT
THAT ENTERS THE W ATLC NEAR 32N48W ALONG 26N60W TO 23N72W WHERE
IT BECOMES STATIONARY ACROSS THE S BAHAMA ISLANDS TO THE N COAST
OF CUBA NEAR 23N81W. SCATTERED SHOWERS ARE POSSIBLE WITHIN
90/120 NM EITHER SIDE OF THE FRONT. A PRE-FRONTAL TROUGH EXTENDS
FROM 23N63W TO SE OF THE TURKS AND CAICOS NEAR 21N71W. THE UPPER
RIDGE OVER THE W CARIBBEAN EXTENDS A NARROW RIDGE AXIS FROM
19N73W ALONG 22N66W 26N54W TO BEYOND 32N45W PROVIDING DIFFLUENCE
ALOFT TO GENERATE SCATTERED TO NUMEROUS SHOWERS/ISOLATED
THUNDERSTORMS FROM 22N-27N BETWEEN 55W-63W AND FROM THE FRONT TO
OVER THE GREATER ANTILLES W OF 69W. THE ABOVE FRONTAL BOUNDARY
SPLITS A BROAD SURFACE RIDGE WITH THE W ATLC RIDGE ANCHORED BY A
SERIES OF 1029 MB HIGHS N OF THE DISCUSSION AREA AND THE E ATLC
RIDGE ANCHORED BY A 1031 MB HIGH N OF THE AZORES. THE FRONT WILL
CONTINUE SE TONIGHT STALLING FROM THE CENTRAL ATLC ACROSS THE
GREATER ANTILLES WED. A WEAK LOW WILL DEVELOP ALONG THE FRONT E
OF THE TURKS AND CAICOS ON THU AND RACE NE DRAGGING THE FRONT E
ON FRI.

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

$$
PAW
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