000 AXNT20 KNHC 291038 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED OCT 29 2014 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...SPECIAL FEATURES... A 1010 MB LOW BEING SUPPORTED BY AN UPPER-LEVEL TROUGH IS NE OF THE LEEWARD ISLANDS NEAR 19N61W. THE LOW IS EMBEDDED IN A HIGH DEEP LAYER MOIST ENVIRONMENT THAT ALONG WITH DIFFLUENT FLOW ALOFT SUPPORT A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION E OF THE LOW CENTER FROM 18N-21N BETWEEN 58W-61W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 18N-23N BETWEEN 54W-61W. DUE TO MARGINAL CONDUCIVE UPPER-LEVEL WINDS...GRADUAL DEVELOPMENT OF THIS DISTURBANCE IS POSSIBLE WHILE IT MOVES W-NW THE NEXT COUPLE OF DAYS. TROPICAL CYCLONE FORMATION CHANCES THROUGH 48 HOURS REMAIN MEDIUM. SEE LATEST NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 17N64W TO 10N67W...MOVING W AT 15-20 KT. THE WAVE IS BEING SUPPORTED BY A LOW TO MIDDLE LEVEL INVERTED TROUGH AND IT IS EMBEDDED IN A SHALLOW MODERATE MOIST ENVIRONMENT. DRY AIR SUBSIDENCE FROM ALOFT IN THIS REGION OF THE BASIN LIMITS THE CONVECTION TO ISOLATED SHOWERS AND TSTMS WITHIN 140 NM EITHER SIDE OF THE WAVE AXIS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 13N16W AND CONTINUES TO 9N21W 8N27W. THE ITCZ BEGINS NEAR 8N27W AND CONTINUES ALONG 6N35W TO 7N42W...THEN RESUMES WEST OF A SURFACE TROUGH FROM 7N47W TO 8N56W. NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION IS FROM 5N-10N E OF 24W. SCATTERED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF A SURFACE TROUGH AXIS ANALYZED FROM 12N31W TO 7N34W. A SECOND SURFACE TROUGH IS ALONG 12N44W TO 4N46W. A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-11N BETWEEN 40W-44W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 3N-11N BETWEEN 40W-50W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER-LEVEL RIDGE IS OVER THE WEST ATLC...THUS SUPPORTING A SURFACE RIDGE THAT EXTENDS AN AXIS SW ACROSS THE FLORIDA PENINSULA TO THE NE GULF. HOWEVER...IN THE MIDDLE- LEVELS...THE BASE OF A BROAD TROUGH OVER THE EASTERN CONUS EXTENDS S TO THE CENTRAL-EASTERN GULF TO SUPPORT A WEAKNESS IN THE SURFACE RIDGE ANALYZED AS A SURFACE TROUGH ALONG 30N87W TO 25N87W. SHALLOW MOIST AIR FROM THE ATLC FRONT ENVIRONMENT AND FORMER TROPICAL CYCLONE HANNA ON THE NW CARIBBEAN HAS BEEN STREAMING INTO THE GULF...THUS SUPPORTING CLOUDINESS NEARBY THE SURFACE TROUGH AND BAY OF CAMPECHE. STRONG DRY AIR SUBSIDENCE FROM ALOFT ACROSS THE REMAINDER BASIN SUSTAINS FAIR WEATHER. WINDS FROM THE E-SE IN THE RANGE OF 5-15 KT DOMINATE. A COLD FRONT WILL REACH THE NE BASIN AND NORTHERN FLORIDA BY WED NIGHT...CONTINUING E-SE ACROSS SOUTHERN FLORIDA THROUGH THU NIGHT. CARIBBEAN SEA... THE REMNANTS OF HANNA ARE BEING ANALYZED AS A SURFACE TROUGH EXTENDING FROM 21N85W TO 13N89W...WHICH CONTINUE TO SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE YUCATAN BASIN...BELIZE...NORTHERN HONDURAS AND NE NICARAGUA. LINGERING MOISTURE ASSOCIATED WITH A FORMER SURFACE TROUGH ACROSS HISPANIOLA CONTINUE TO ENHANCE ISOLATED SHOWERS OVER THE ISLAND AS WELL AS IMMEDIATE ADJACENT WATERS. THE SHOWERS ARE BEING SUPPORTED BY AN UPPER LEVEL TROUGH DIPPING ACROSS THE CENTRAL AND EASTERN CARIBBEAN. A TROPICAL WAVE IS MOVING OVER THE EASTERN BASIN. THIS WAVE IS BEING SUPPORTED BY AN INVERTED LOW- TO MIDDLE-LEVEL TROUGH...HOWEVER STRONG DRY AIR SUBSIDENCE FROM ALOFT IN THIS REGION OF THE BASIN IS HINDERING THE DEVELOPMENT OF DEEP CONVECTION. SEE TROPICAL WAVES SECTIONS ABOVE FOR MORE DETAILS. A LOW PRESSURE SYSTEM CENTERED NE OF THE LEEWARD ISLANDS IS EXPECTED TO DRIFT WESTWARD TOWARDS HISPANIOLA BY FRIDAY NIGHT. THIS AREA OF LOW PRESSURE IS EXPECTED TO GENERATE SHOWERS ACROSS PUERTO RICO WED THROUGH THU AND FOR HISPANIOLA THU TO SAT. HISPANIOLA... LINGERING MOISTURE ASSOCIATED WITH A FORMER SURFACE TROUGH ACROSS HISPANIOLA CONTINUE TO ENHANCE ISOLATED SHOWERS OVER THE ISLAND AS WELL AS ADJACENT WATERS. THE SHOWERS ARE BEING SUPPORTED BY AN UPPER LEVEL TROUGH DIPPING ACROSS THE CENTRAL AND EASTERN CARIBBEAN. A LOW PRESSURE SYSTEM CENTERED NE OF THE LEEWARD ISLANDS IS EXPECTED TO DRIFT WESTWARD TOWARDS HISPANIOLA BY FRIDAY NIGHT. THIS AREA OF LOW PRESSURE IS EXPECTED TO GENERATE SHOWERS ACROSS HISPANIOLA THU TO SAT. ATLANTIC OCEAN... THE HIGHLIGHT IN THE BASIN IS A DISTURBANCE JUST NE OF THE LEEWARD ISLANDS...WHICH IS DISCUSSED IN THE SPECIAL FEATURES SECTION. A MIDDLE TO UPPER LEVEL TROUGH OVER THE CENTRAL ATLC N OF 28N CONTINUE TO SUPPORT A COLD FRONT ANALYZED FROM 30N43W SW TO 27N52W WHERE IT TRANSITIONS TO A STATIONARY FRONT ALONG 27N63W TO 23N70W. A SURFACE PRE-FRONTAL TROUGH IS FROM 25N65W TO 19N69W. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE FRONTAL BOUNDARY. EAST AND WEST OF THE FRONTAL BOUNDARY...SURFACE RIDGING AND FAIR WEATHER DOMINATE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR