000 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