000 AXNT20 KNHC 262352 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 26 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. ...SPECIAL FEATURES... TROPICAL DEPRESSION IDA IS CENTERED NEAR 24.4N 47.1W AT 26/2100 UTC OR ABOUT 970 NM E-NE OF THE NORTHERN LEEWARD ISLANDS MOVING NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 23N- 26N BETWEEN 44W-46W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE NE CORNER OF THE YUCATAN PENINSULA THAT SUPPORTS A 1008 MB LOW CENTERED NEAR 19N88W. THE SURFACE LOW... PARTIALLY EXPOSED DUE TO SOUTHWESTERLY WIND SHEAR...IS GENERATING SCATTERED MODERATE CONVECTION MAINLY NE OF THE LOW CENTER FROM 18N-25N BETWEEN 82W-88W ACROSS PORTIONS OF THE NW CARIBBEAN SEA AND SE GULF OF MEXICO. WHILE THE LOW IS EXPECTED TO MOVE NORTH AT 10 KT DURING THE NEXT 24 TO 36 HOURS...IT WILL BEGIN TO INTERACT WITH A STRONGER MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE TEXAS COAST. ASIDE FROM THE MEDIUM POTENTIAL TO BECOME A TROPICAL CYCLONE...THE PRIMARY IMPACT FROM THIS SYSTEM WILL REMAIN HEAVY RAINFALL AS IT TRACKS NORTHWARD ACROSS THE EASTERN GULF OF MEXICO THROUGH MONDAY. MID-LEVEL ENERGY IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY OF 26N67W THAT SUPPORTS A 1011 MB SURFACE LOW CENTERED NEAR 27N69W. A SURFACE TROUGH AXIS EXTENDS S-SW TO 22N71W WITH SCATTERED MODERATE CONVECTION OCCURRING GENERALLY WITHIN THE EASTERN SEMICIRCLE OF THE LOW WITHIN 210 NM OF CENTER. THE SYSTEM HOLDS A MEDIUM CHANCE FOR TROPICAL CYCLONE DEVELOPMENT DURING THE NEXT 48 HOURS AS IT MOVES NORTHWARD AT 5-10 KT. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N34W TO 17N32W MOVING W AT 5 KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING ALOFT BETWEEN 25W- 38W. ISOLATED MODERATE CONVECTION REMAINS LIMITED AND GENERALLY OCCURRING WITHIN 120 NM EITHER SIDE OF A LINE FROM 16N25W TO 10N36W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO 09N18W TO 11N28W TO 06N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N40W TO 01N50W. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 07N-15N BETWEEN 10W-17W. WIDELY SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 08N-14N BETWEEN 17W-21W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 03N-10N BETWEEN 32N-43W. ...DISCUSSION... GULF OF MEXICO... AN ELONGATED AND BROAD UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED OVER SOUTH-CENTRAL TEXAS THIS EVENING PROVIDING MUCH OF THE GULF WITH SOUTH-SOUTHWESTERLY DIFFLUENT FLOW ALOFT. THE MID-LEVEL LOW IS SLIGHTLY OFFSET TO THE EAST FROM THE UPPER LEVEL LOW OVER THE NW GULF WITH PLENTY OF RELATIVE VORTICITY AND DIFFLUENCE GENERATING WIDELY SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF THE GULF BASIN. GIVEN THE RELATIVE STRENGTH OF THE UPPER LEVEL DYNAMICS...LOW PRESSURE REMAINS FOCUSED ON A 1009 MB LOW CENTERED NEAR 24N94W WITH A SURFACE TROUGH EXTENDING N-NE TO 28N89W AND S-SE TO 19N92W. THE GENERAL SYNOPTIC-SCALE LOW PRESSURE AREA REACHES SE TO ANOTHER LOW...THE 1008 MB SPECIAL FEATURE...CENTERED ACROSS THE SE YUCATAN PENINSULA NEAR 19N88W. BOTH OF THESE LOW PRESSURE AREAS ARE EXPECTED TO DRIFT NORTHWARD DURING THE NEXT 24-36 HOURS WITH PLENTY OF PRECIPITATION OCCURRING AS A RESULT ACROSS THE EASTERN GULF WATERS AND PORTIONS OF THE FLORIDA PENINSULA. CARIBBEAN SEA... AN UPPER LEVEL RIDGE AXIS EXTENDS NORTH-SOUTH ALONG 80W OVER THE WESTERN CARIBBEAN. ON THE WESTERN PERIPHERY OF THE RIDGING ALOFT...SOUTHWESTERLY FLOW AND OVERALL DIFFLUENCE PREVAIL GENERATING AREAS OF SCATTERED SHOWERS AND ISOLATED TSTMS N OF 17N W OF 75W...AND S OF 17N W OF 82W. THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 10N BETWEEN NORTHERN COLOMBIA AND COSTA RICA IS ALSO PROVIDING FOCUS FOR SCATTERED SHOWERS AND TSTMS ACROSS INTERIOR PORTIONS OF CENTRAL AMERICA THIS EVENING. ON THE EASTERN PERIPHERY OF THE UPPER LEVEL RIDGING... RELATIVELY DRY NORTHERLY FLOW DOMINATES PROVIDING GENERALLY CLEAR SKIES AND FAIR CONDITIONS E OF 75W. THIS NORTHERLY FLOW ALOFT IS ALSO FOUND ON THE WESTERN PERIPHERY OF A BROAD UPPER LEVEL LOW CENTERED NEAR 18N62W WHICH RETAINS VERY LITTLE IMPACT ON THE BASIN AT THIS TIME. OTHERWISE...MAINLY FRESH TO OCCASIONAL STRONG TRADES PERSIST WITH THE STRONGEST WINDS NOTED ACROSS SOUTH-CENTRAL PORTIONS. BY MID-WEEK...THE TRADES ARE EXPECTED TO RELAX SOMEWHAT INTO MODERATE TO FRESH BREEZE LEVELS. ...HISPANIOLA... CURRENTLY LINGERING LATE AFTERNOON AND EARLY EVENING ISOLATED SHOWERS CONTINUE TO GRADUALLY DIMINISH WITH MOSTLY FAIR SKIES EXPECTED FOR THE OVERNIGHT HOURS INTO EARLY SUNDAY. NORTHERLY FLOW ALOFT PREVAILS OVER THE ISLAND PROVIDING MOSTLY STABLE CONDITIONS AT THIS TIME. ATLANTIC OCEAN... ASIDE FROM THE SPECIAL FEATURES LOW CENTERED NEAR 27N69W...THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF WEAK SURFACE RIDGING WITH ONLY A FEW ISOLATED SHOWERS AND TSTMS OCCURRING ACROSS THE FLORIDA PENINSULA AND NEAR SHORE WATERS W OF 79W THIS EVENING. THIS CONVECTION IS LARGELY DUE TO UPPER LEVEL DIFFLUENCE IN ASSOCIATION WITH THE SPECIAL FEATURES LOW PRESSURE AREA ACROSS THE YUCATAN PENINSULA. FARTHER EAST ACROSS THE CENTRAL ATLC IS TROPICAL DEPRESSION IDA...WITH A FRONTAL BOUNDARY ANALYZED NORTH OF THE DISCUSSION AREA ALONG 34N BETWEEN 40W AND 75W. OTHERWISE...THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1019 MB HIGH CENTERED NEAR 30N32W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN