000 AXNT20 KNHC 211755 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON OCT 21 2013 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... TROPICAL DEPRESSION THIRTEEN FORMED AT 1500 UTC. ITS CENTER IS NEAR 28.0N 55.1W OR 564 NM ESE OF BERMUDA AND IS MOVING NE AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT33 KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS E-NE OF THE CENTER FROM 27N-31N BETWEEN 51W-55W. ...TROPICAL WAVES... TROPICAL WAVE AXIS EXTENDS FROM 14N40W TO 05N37W AND MOVES WEST AT 10-15 KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT. STRONG NORTHWESTERLY WIND SHEAR INHIBITS IN PART DEEP CONVECTION. SCATTERED MODERATE CONVECTION IS ACROSS THE CENTRAL SECTOR OF THE WAVE FROM 07N-10N WITHIN 320 NM EITHER SIDE OF THE AXIS. THIS CONVECTION IS MOSTLY ASSOCIATED WITH THE ITCZ. TROPICAL WAVE AXIS EXTENDS FROM 19N68W TO 11N70W AND MOVES WEST AT 10-15 KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS MOSTLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT. DRY AIR SUBSIDENCE FROM THE MIDDLE LEVELS AND STRONG W-NW WIND SHEAR IN THE CENTRAL CARIBBEAN ARE HINDERING DEEP CONVECTION. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL WEST AFRICA NEAR 18N16W TO 08N25W. THE ITCZ CONTINUES FROM 08N25W TO 05N35W AND THEN CONTINUES WEST OF A TROPICAL WAVE FROM 09N44W TO 08N55W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN 19W-35W. SIMILAR CONVECTION IS WITHIN 140 NM NORTH OF THE ITCZ AXIS BETWEEN 44W-53W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE-LEVEL TROUGH WITH AXIS MOVING ACROSS CENTRAL U.S.A TO CENTRAL MEXICO IS SUPPORTING A STATIONARY FRONT THAT PASSES THROUGH NORTH-CENTRAL FLORIDA TO 28N82W 26N90W TO 24N96W. BOTH THE SSMI TOTAL PRECIPITABLE WATER AND WATER VAPOR IMAGERY INDICATE THAT HIGH MOISTURE IS BEING ADVECTED FROM THE EAST PACIFIC TO THE WESTERN GULF. THIS MOISTURE IS SUPPORTING RAINSHOWERS AND ISOLATED TSTMS OVER THE NW GULF N OF THE FRONTAL BOUNDARY W OF 90W AND ISOLATED SHOWERS AND TSTMS FROM 20N-24N BETWEEN 93W-96W. THE WESTERN PERIPHERY OF AN UPPER-LEVEL RIDGE COVERS THE REMAINDER GULF. DRY AIR SUBSIDENCE IS SUPPORTING FAIR WEATHER ACROSS THE EASTERN GULF. THE STATIONARY FRONT WILL START DISSIPATING ACROSS THE GULF WITHIN THE NEXT 24 HOURS. A NEW COLD FRONT WILL BE ENTERING THE NW GULF EARLY ON TUESDAY AND IS EXPECTED TO EXTEND ACROSS THE CENTRAL BASIN DURING THE NIGHT HOURS. A SECOND REINFORCING COLD FRONT ENTERS THE N-NE GULF BY WED NIGHT. SHOWERS ARE EXPECTED TO CONTINUE IN ASSOCIATION WITH THE FRONTAL BOUNDARY/IES. THE CARIBBEAN SEA... A TROPICAL WAVE AXIS EXTENDS FROM 19N68W TO 11N70W. SSMI TOTAL PRECIPITABLE WATER IMAGERY INDICATE THE WAVE IS MOSTLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT. DRY AIR SUBSIDENCE FROM THE MIDDLE LEVELS AND STRONG W-NW WIND SHEAR IN THE CENTRAL CARIBBEAN ARE SUPPRESSING CONVECTIVE ACTIVITY. IN THE SOUTHERN BASIN...THE MONSOON TROUGH EXTENDS FROM NORTHERN COSTA RICA TO CENTRAL PANAMA TO NORTHERN COLOMBIA. HIGH MOISTURE AND UPPER- LEVEL DIVERGENCE IN THIS REGION IS SUPPORTING HEAVY SHOWERS AND TSTMS S OF 15N BETWEEN 75W-84W. SCATTERED SHOWERS AND TSTMS EXTENDS WITHIN 110 NM OF THE EASTERN HONDURAS COAST. A MIDDLE TO UPPER LEVEL LOW CENTERED N OF PUERTO RICO NEAR 21N66W IS SUPPORTING A 1014 MB LOW AND A TROUGH THAT EXTENDS FROM 24N63W TO 19N64W. EAST OF THE UPPER-LEVEL LOW...THE WESTERN PERIPHERY OF A RIDGE IS GENERATING DIFFLUENT FLOW ALOFT TO SUPPORT HEAVY SHOWERS AND TSTMS OVER PUERTO RICO...THE LEEWARD AND VIRGIN ISLANDS. SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER THE SOUTHERN WINDWARD ISLANDS BEING SUPPORTED BY MIDDLE TO UPPER LEVEL DIFFLUENCE. OTHERWISE...WATER VAPOR IMAGERY SHOW DRY AIR SUBSIDING OVER THE REMAINDER BASIN WHICH IS SUPPORTING FAIR WEATHER. THE TROPICAL WAVE WILL CONTINUE TO DRIFT W-NW. THE NORTHERN PORTION OF THE AXIS IS EXPECTED TO BE IN THE WINDWARD PASSAGE BY TUESDAY NIGHT AND OVER EASTERN CUBA BY WEDNESDAY NIGHT. HISPANIOLA... THE NORTHERN PORTION OF A TROPICAL WAVE AXIS IS MOVING ACROSS EASTERN DOMINICAN REPUBLIC. HOWEVER...DRY AIR SUBSIDENCE FROM THE MIDDLE LEVELS AND STRONG W-NW WIND SHEAR ARE SUPPRESSING CONVECTIVE ACTIVITY. THE WAVE WILL CONTINUE TO MOVE W-NW AND IS EXPECTED TO BE ACROSS THE WINDWARD PASSAGE BY TUESDAY NIGHT. SHOWERS ARE NOT LIKELY TO DEVELOP ACROSS THE ISLAND TODAY AS STRONG DRY AIR SUBSIDENCE IS EXPECTED TO PREVAIL THROUGH THE NIGHT HOURS. HOWEVER...A MOIST AIRMASS IS EXPECTED TO MOVE ACROSS THE ISLAND STARTING TUESDAY MORNING WHICH WILL ENHANCE CONVECTIVE ACTIVITY. THE ATLANTIC OCEAN... THE MOST PROMINENT FEATURE IN THE ATLC IS TROPICAL DEPRESSION THIRTEEN WHICH IS DISCUSSED IN THE SPECIAL FEATURES SECTION. OVER THE SW N ATLC...A WEAK STATIONARY FRONT ENTERS THE AREA OF DISCUSSION NEAR 30N78W SW TO CAPE CANAVERAL FLORIDA...ACROSS NORTH-CENTRAL FLORIDA TO THE GULF. RAINSHOWERS ARE WITHIN 50 NM NW OF THE FRONTAL BOUNDARY. A 1015 MB SURFACE LOW IS LOCATED EAST OF THE FRONT NEAR 29N72W WITH NO CONVECTION ASSOCIATED WITH IT. A MIDDLE TO UPPER LEVEL LOW CENTERED N OF PUERTO RICO NEAR 21N66W IS SUPPORTING A 1014 MB LOW AND A TROUGH THAT EXTENDS FROM 24N63W TO 19N64W. EAST OF THE UPPER-LEVEL LOW...THE WESTERN PERIPHERY OF A RIDGE IS GENERATING DIFFLUENT FLOW ALOFT TO SUPPORT HEAVY SHOWERS AND TSTMS FROM 16N-24N BETWEEN 58W-65W. IN THE CENTRAL ATLC AND EAST OF THE TROPICAL DEPRESSION...A 1021 MB HIGH IS CENTERED NEAR 27N45W WHICH IS EXPECTED TO DRIFT SE WITHIN THE NEXT 24 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR