000 AXNT20 KNHC 150000 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN SEP 14 2008 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... NONE. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 29W S OF 13N MOVING W 10-15 KT. THIS WAVE IS LOW AMPLITUDE AND EMBEDDED WITHIN THE ITCZ. ANY SHOWERS AND CONVECTION ARE ASSOCIATED WITH THE ITCZ. TROPICAL WAVE IS ALONG 50W FROM 10N-20N WITH A 1012 MB LOW ANALYZED ALONG THE WAVE AXIS NEAR 17N MOVING W 10-15 KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE AS INDICATED BY MIMIC-TPW ANIMATION. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-19N BETWEEN 46W-50W. TROPICAL WAVE IS ALONG 69W S OF 20N MOVING W 10-15 KT. THIS WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AND PREDOMINATELY EASTERLY SURFACE FLOW IS OBSERVED ON SATELLITE IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 16N-19N BETWEEN 64W-70W INCLUDING PUERTO RICO...THE VIRGIN ISLANDS AND ERN HISPANIOLA. TROPICAL WAVE IS ALONG 80W S OF 19N MOVING W 10-15 KT. THIS WAVE IS BENEATH STRONG SOUTHERLY UPPER FLOW WHICH IS PROVIDING AMPLE UPPER DIFFLUENCE TO GENERATE SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 8N-19N W OF 77W TO INLAND OVER NICARAGUA...COSTA RICA AND PANAMA. ...THE ITCZ... ITCZ AXIS IS ANALYZED ALONG 13N16W 10N27W 9N31W 9N48W 10N53W 9N62W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM OF A LINE FROM 10N21W TO 6N29W. SIMILAR CONVECTION IS WITHIN 90 NM ON EITHER SIDE OF THE AXIS BETWEEN 42W TO 48W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH IS ACROSS THE WRN CONUS AND EXTENDS A COLD FRONT ALONG THE TEXAS GULF COAST. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM SW LOUISIANA TO JUST SOUTH OF CORPUS CHRISTI TEXAS. SCATTERED SHOWERS/TSTMS ARE ACROSS THE NW GULF N OF A LINE FROM CAMERON LOUISIANA TO NEAR BROWNSVILLE TEXAS. AN UPPER LEVEL HIGH IS CENTERED OFFSHORE OF THE ERN US SEABOARD IN THE W ATLC NEAR 34N75W AND EXTENDS RIDGING ACROSS THE ERN FLORIDA PENINSULA. AN UPPER LOW IS CENTERED OVER THE CENTRAL GULF NEAR 24N89W AND IS PROVIDING A LARGE PORTION OF THE GULF WITH MODERATE TO STRONG SUBSIDENCE/DRY AIR E OF THE AFOREMENTIONED SURFACE TROUGH IN THE NW GULF AND N OF 20N. A SURFACE RIDGE EXTENDS FROM A 1018 MB HIGH IN THE W ATLC TO OVER CENTRAL FLORIDA AND THE NE GULF WATERS. S-SE SURFACE WINDS CONTINUE EAST OF THE FRONTAL BOUNDARY. CARIBBEAN SEA... AN UPPER HIGH IS CENTERED OVER THE CENTRAL CARIBBEAN NEAR 15N76W AND COVERS MUCH OF THE CARIBBEAN EXCEPT FOR THE FAR NW CARIBBEAN WHERE UPPER TROUGHING IS ACROSS THE YUCATAN PENINSULA AND YUCATAN CHANNEL. SCATTERED SHOWERS AND TSTMS ARE ACROSS SRN MEXICO AND THE YUCATAN PENINSULA WITH MULTILAYERED CLOUDINESS EXTENDING NE OFF THE ERN YUCATAN PENINSULA. UPPER LEVEL DIFFLUENCE ACROSS THE WRN CARIBBEAN IS GENERATING SCATTERED SHOWERS/TSTMS FROM 8N-19N W OF 76W TO INLAND OVER PORTIONS OF SOUTH AND CENTRAL AMERICA. THE SCATTERED SHOWER/TSTM ACTIVITY OVER THE FAR NE CARIBBEAN IS ASSOCIATED WITH THE TROPICAL WAVE ALONG 69W...OTHERWISE THE REMAINDER OF THE CARIBBEAN REMAINS TRANQUIL THIS EVENING. ATLANTIC OCEAN... AN UPPER LEVEL HIGH IS CENTERED OFFSHORE OF THE ERN US SEABOARD IN THE W ATLC NEAR 34N75W AND EXTENDS RIDGING W OF 63W TO OVER THE ERN FLORIDA PENINSULA. MULTILAYERED CLOUDINESS IS ACROSS THE W/CENTRAL ATLC FROM 20N TO NORTH OF THE REGION BETWEEN 50W-70W. A SURFACE TROUGH EXTENDS ACROSS THE NW BAHAMAS DRIFTING NW ALONG THE SRN PERIPHERY OF THE UPPER HIGH AND IS GENERATING ISOLATED SHOWERS ACROSS THE NW BAHAMAS AND THE STRAITS OF FLORIDA THIS EVENING. AN UPPER TROUGH EXTENDS FROM AN E ATLC UPPER LOW NEAR 30N24W THROUGH A CENTRAL ATLC UPPER LOW NEAR 25N46W CONTINUING SOUTHWARD INTO THE W TROPICAL ATLC TO NEAR 17N56W...NE OF THE LESSER ANTILLES ISLANDS. AN UPPER HIGH IS IN THE E TROPICAL ATLC WEST OF THE CAPE VERDE ISLANDS NEAR 16N27W WITH AN INVERTED UPPER TROUGH EXTENDING FROM SURINAME SOUTH AMERICA TO NEAR 15N55W SEPARATING THE UPPER HIGH AND THE UPPER TROUGH THAT EXTENDS FROM THE CENTRAL ATLC. A BROAD SURFACE RIDGE IS OVER THE ATLC N OF 22N E OF 55W ANCHORED BY A 1022 MB HIGH NEAR 34N25W. A WEAK 1015 MB LOW IS CENTERED NEAR 23N30W AND IS PRODUCING POSSIBLE ISOLATED SHOWERS FROM 21N-25N BETWEEN 24W-31W. A SECOND NARROW SURFACE RIDGE EXTENDS ALONG 31N W OF 70W TO ACROSS THE NE GULF OF MEXICO IS ANCHORED BY A 1018 MB HIGH CENTERED NEAR 31N74W. $$ HUFFMAN