000 AXNT20 KNHC 072344 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON OCT 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... A 1010 MB SURFACE LOW IS EMBEDDED WITHIN THE MONSOON TROUGH CENTERED NEAR 09N27W. THE LOW REMAINS THE FOCUS OF A RELATIVELY BROAD MONSOONAL GYRE THAT COVERS THE EASTERN TROPICAL ATLC FROM 06N-14N BETWEEN 18W-33W AND FALLS BENEATH THE WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 11N21W. THIS IS PROVIDING AMPLE MIDDLE TO UPPER LEVEL DIFFLUENT IN THE VICINITY OF THE LOW WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION FROM 06N-13N BETWEEN 20W-30W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N34W TO 19N34W MOVING W-NW AT 10-15 KT. THE WAVE CONTINUES TO PROPAGATE WESTWARD AWAY FROM THE SPECIAL FEATURES LOW MENTIONED ABOVE WITH TOTAL PRECIPITABLE WATER IMAGERY INDICATING THE POLEWARD EXTENSION OF MOISTURE FROM A MAXIMUM NEAR 10N27W NW TO 17N35W N-NE TO 24N32W. WHILE FARTHER NW FROM THE LOW EMBEDDED WITHIN THE MONSOON TROUGH...UPPER LEVEL SOUTH-SOUTHWESTERLY SHEAR INCREASES AS A DRIER AIRMASS IS NOTED W OF 35W AND AS A RESULT NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. TROPICAL WAVE EXTENDS FROM 11N64W TO 18N65W MOVING W AT 10-15 KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE COVERING THE EASTERN CARIBBEAN BETWEEN 58W-68W AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE IS ALSO LOCATED BENEATH THE EASTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 15N64W. ISOLATED MODERATE CONVECTION IS FROM 13N-19N BETWEEN 58W- 67W AND IS LIKELY ENHANCED BY THE UPPER LEVEL DIFFLUENT PROVIDING BY THE ANTICYCLONE ALOFT. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N15W INTO THE 1010 MB SPECIAL FEATURES LOW NEAR 09N27W TO 08N33W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N34W TO 03N39W TO THE EQUATOR NEAR 48W. NO SIGNIFICANT CONVECTION IS NOTED ON SATELLITE IMAGERY OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE SPECIAL FEATURES LOW. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM OVER THE WESTERN FLORIDA PANHANDLE NEAR 31N87W SW TO 24N95W THAT SUPPORTS A 1007 MB LOW CENTERED NEAR THE FLORIDA BIG BEND NEAR 29N83W AND THE ASSOCIATED COLD FRONT EXTENDING FROM THE LOW ALONG 26N85W TO 24N90W TO 22N94W TO THE MEXICO COAST NEAR 19N96W. THE FRONT REMAINS RELATIVELY DRY N OF 25N...HOWEVER SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING MAINLY SOUTHEAST OF THE FRONT AND W OF 87W...INCLUDING INLAND PORTIONS OF SOUTHERN MEXICO AND THE YUCATAN PENINSULA THIS EVENING. FARTHER NORTH...MOST OF THE CONVECTIVE ACTIVITY IS OCCURRING ACROSS THE EASTERN FLORIDA PENINSULA AND INTO THE SW NORTH ATLC REGION. OTHERWISE...THE REMAINDER OF THE NW AND NORTH-CENTRAL GULF IS UNDER THE INFLUENCE OF NORTHERLY WINDS GENERALLY IN THE RANGE OF 10 TO 20 KT WITH CLEAR SKIES AS HIGH PRESSURE BUILDS IN ACROSS TEXAS AND EASTERN MEXICO. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES GENERALLY NORTHWESTERLY UPPER LEVEL FLOW W OF 74W ON THE WESTERN PERIPHERY OF AN UPPER LEVEL TROUGH EXTENDING INTO THE CARIBBEAN FROM THE SW NORTH ATLC ALONG 28N72W TO A BASE NEAR 15N76W. IMAGERY INDICATES RELATIVELY DRY AIR ALOFT AND THIS IS RESULTING IN MOSTLY CLEAR SKIES AND FAIR CONDITIONS THIS EVENING. HOWEVER WITH PEAK DAYTIME HEATING AND INSTABILITY...A FEW LINGERING SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING W OF A LINE FROM 21N87W TO 12N82W... INCLUDING THE YUCATAN PENINSULA...HONDURAS...AND NICARAGUA. FARTHER SOUTH...LOW-LEVEL MOISTURE CONVERGENCE AND THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 10N IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 12N BETWEEN 71W-83W. FINALLY...A TROPICAL WAVE IS ANALYZED ALONG 65W THAT IS PROVIDING MUCH OF THE EASTERN CARIBBEAN E OF 68W WITH INCREASED LOW-LEVEL MOISTURE AND PRECIPITATION. ALOFT...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 14N64W AND THIS IS LIKELY ENHANCING SCATTERED SHOWERS AND ISOLATED TSTMS IN THE VICINITY OF THE TROPICAL WAVE AND ACROSS THE LESSER ANTILLES THIS EVENING FROM 12N-19N BETWEEN 58W-68W. HISPANIOLA... CURRENTLY AFTERNOON AND EARLY EVENING SCATTERED SHOWERS AND TSTMS ARE GRADUALLY DIMINISHING WITH THE LOSS OF PEAK DAYTIME HEATING AND INSTABILITY. OTHERWISE...HISPANIOLA LIES EAST OF AN UPPER LEVEL TROUGH AXIS THAT EXTENDS FROM THE SW NORTH ATLC NEAR 28N72W TO 15N76W AND THIS IS PROVIDING FOR AN OVERALL UPPER LEVEL DIFFLUENT ENVIRONMENT. GIVEN THIS ENVIRONMENT AND THE ANTICIPATED SLOW MOVEMENT OF THE TROUGHING THROUGH WEDNESDAY... ISOLATED SHOWERS ARE FORECAST THROUGH THE OVERNIGHT HOURS WITH INCREASED AREAL COVERAGE OF CONVECTION DURING THE AFTERNOON AND EVENING HOURS. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE EASTERN GULF OF MEXICO OVER THE FLORIDA PENINSULA INTO THE SW NORTH ATLC NEAR 31N76W. THIS IS PROVIDING AN OVERALL UPPER LEVEL DIFFLUENT ENVIRONMENT ACROSS THE SW NORTH ATLC AHEAD OF A COLD FRONT CURRENTLY LOCATED ACROSS THE GULF OF MEXICO. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING N OF 25N W OF 78W AS THE REMNANT LOW OF KAREN AND THE ASSOCIATED FRONT BOUNDARY CONTINUES TO MOVE EAST OVER THE NEXT 24 TO 36 HOURS. FARTHER EAST...A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY NEAR 29N72W THAT SUPPORTS A 1013 MB LOW CENTERED NEAR 25N65W AND SURFACE TROUGHING EXTENDING NE FROM THE LOW TO 29N60W AND SW FROM THE LOW TO 23N67W. LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH PLENTY OF MIDDLE TO UPPER LEVEL DIFFLUENCE IS PROVIDING FOR A RATHER LARGE AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-32N BETWEEN 52W-68W. SOME OF THIS CONVECTIVE ACTIVITY STRETCHES SOUTHWARD ACROSS THE LESSER ANTILLES FROM 12N-20N BETWEEN 58W-63W AND IS MORE LIKELY ASSOCIATED WITH UPPER LEVEL RIDGING TO THE SOUTH OVER THE EASTERN CARIBBEAN SEA. FINALLY...AN UPPER LEVEL SHORTWAVE TROUGH IS LOCATED IN THE VICINITY OF 26N43W AND STRETCHES TROUGHING INFLUENCE NORTHWARD TO AN UPPER LEVEL LOW CENTERED NEAR 43N41W. WHILE NO SIGNIFICANT SURFACE FEATURES ARE ASSOCIATED WITH THE SHORTWAVE TROUGH...THE MAIN DEEP LAYERED LOW TO THE NORTH SUPPORTS A COLD FRONT ANALYZED FROM 36N40W TO 33N50W TO 34N58W AND IS EXPECTED TO SKIRT THE NORTHERN FRINGE OF THE DISCUSSION AREA. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE COLD FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN