000 AXNT20 KNHC 081747 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST WED DEC 08 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS ALONG 08N13W 05N37W 06N49W 05N53W. ISOLATED MODERATE CONVECTION IS FROM 03N-09N BETWEEN 12W-21W...AND WITHIN 150 NM NORTH OF THE AXIS BETWEEN 21W-29W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 150 NM NORTH OF THE AXIS BETWEEN 45W-54W. THIS AREA OF CONVECTION IS ENHANCED BY THE EASTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 11N56W. ...DISCUSSION... GULF OF MEXICO... AS OF 08/1500 UTC...A 1016 MB LOW IS CENTERED NEAR 27N93W WITH A COLD FRONT TRAILING SOUTH FROM THE LOW ALONG 25N94W 22N96W TO INLAND OVER MEXICO NEAR 20N97W. A WARM FRONT ALSO EXTENDS EASTWARD FROM THE LOW ALONG 27N90W TO 28N87W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 90 NM EAST OF THE COLD FRONT...WHILE SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM NORTH OF THE WARM FRONT. THIS FRONTAL SYSTEM IS SUPPORTED ALOFT BY AN UPPER LEVEL SHORTWAVE TROUGH CURRENTLY PROGRESSING EASTWARD ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. THE SURFACE LOW IS FORECAST TO MOVE SE OVER THE NEXT 24 HOURS AND POSITION ITSELF OVER WESTERN CUBA BY EARLY THURSDAY. AS THE COLD FRONT PUSHES EASTWARD...STRONG N TO NE WINDS ARE FORECAST IN WAKE OF THE FRONT...BUT BY FRIDAY AS SURFACE RIDGING BUILDS BACK OVER THE NW GULF...WINDS WILL VEER SOUTHERLY AHEAD OF THE NEXT COLD FRONT FORECAST TO ENTER THE NW GULF WATERS BY LATE SATURDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES VERY DRY SOUTHWESTERLY FLOW ALOFT IS LOCATED OVER THE NW CARIBBEAN EAST OF AN UPPER LEVEL SHORTWAVE TROUGH SWEEPING QUICKLY ACROSS THE SE CONUS AND NORTHERN GULF OF MEXICO. THIS SUBSIDENCE IS CONTINUING TO PROVIDE GENERALLY FAIR CONDITIONS OVER THE NW CARIBBEAN... CUBA...AND JAMAICA THIS AFTERNOON. FARTHER EAST...A SHEARLINE MEANDERS FROM HISPANIOLA NEAR 19N72W TO 15N75W INTO A NEARLY STATIONARY 1010 MB LOW CENTERED NEAR 10N80W. STRONGER NE WINDS AND EASTERLY TRADES CONVERGE ALONG THE AXIS OF THE SHEAR LINE AND INTO THE LOW PRESSURE CENTER PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 150 NM EITHER SIDE OF A LINE FROM 17N72W TO 09N80W. THIS AREA OF CONVECTIVE ACTIVITY LIES ON THE WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED IN THE TROPICAL NORTH ATLC NEAR 11N56W. EAST OF THE SHEAR LINE... LOW-LEVEL MOISTURE CONTINUES TO STREAM FROM THE CENTRAL ATLC OVER THE EASTERN CARIBBEAN AND PROVIDE THE LESSER ANTILLES... PUERTO RICO...AND EASTERN DOMINICAN REPUBLIC WITH ISOLATED SHOWERS THROUGH THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ATLANTIC OCEAN... A DEEP LAYER TROUGH IS OVER THE WESTERN NORTH ATLC AND SUPPORTS A PAIR OF FRONTAL BOUNDARIES ANALYZED INTO THE DISCUSSION AREA. FIRST...A DISSIPATING STATIONARY FRONT ENTERS THE REGION NEAR 32N56W AND EXTENDS SW TO HISPANIOLA NEAR 20N70W. WHILE MOST OF THE UPPER LEVEL SUPPORT FOR THIS FRONT REMAINS NORTH OF 29N... ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARY N OF 25N. WEST OF THE WANING STATIONARY FRONT...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N61W THAT EXTENDS SW TO NEAR 26N70W. NO SIGNIFICANT CONVECTION IS NOTED WITH THE COLD FRONT...HOWEVER A 08/1416 UTC ASCAT PASS DEPICTED STRONGER NW WINDS TO 25 KT N OF 29N BETWEEN THE FRONT AND 68W. FARTHER EAST...AN UPPER LEVEL RIDGE AXIS EXTENDS ALONG 45W AND SUPPORTS A SURFACE RIDGE WITH AXIS FROM 32N42W TO 20N55W THAT CONTINUES TO PRODUCE FAIR CONDITIONS ACROSS MUCH OF THE CENTRAL ATLC BETWEEN 30W-52W. OVER THE EASTERN ATLC...AN UPPER LEVEL TROUGH IS EVIDENT ON WATER VAPOR IMAGERY WITH AXIS ALONG 26W DIPPING SOUTHWARD TO 07N. THE UPPER LEVEL TROUGH SUPPORTS A 1005 MB LOW CENTERED OVER THE MADEIRA ISLANDS NEAR 34N16W WITH A SURFACE TROUGH ANALYZED FROM THE LOW TO 23N29W. ISOLATED SHOWERS GENERALLY REMAIN N OF 27N BETWEEN 17W-27W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN