000 AXNT20 KNHC 190553 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED SEP 19 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... A LARGE AREA OF DISTURBED WEATHER OVER THE WESTERN ATLANTIC... NORTHERN BAHAMAS...AND THE EAST COAST OF FLORIDA IS ASSOCIATED WITH A 1012 MB SFC LOW LOCATED NEAR 25N79W AT 19/0300 UTC INTERACTING WITH AN UPPER-LEVEL LOW. THERE ARE NO SIGNS OF ORGANIZATION AT THIS TIME. HOWEVER...SURFACE PRESSURES ARE GRADUALLY FALLING AND ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR A SUBTROPICAL OR A TROPICAL CYCLONE TO FORM OVER THE NEXT DAY OR TWO...AS THE DISTURBANCE MOVES WESTWARD OVER FLORIDA AND INTO THE GULF OF MEXICO. REGARDLESS OF DEVELOPMENT...THIS SYSTEM WILL LIKELY BRING SHOWERS...SQUALLS...AND LOCALLY HEAVY RAINS OVER PORTION OF FLORIDA DURING THE NEXT DAY OR TWO. MOSAIC DOPPLER RADAR FROM THE SE US SHOWS SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED TSTMS ALONG THE EAST FLORIDA COAST AND ADJACENT COASTAL WATERS NORTH OF WEST PALM BEACH. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 26W/27W S OF 16N MOVING W 10-15 KT. A BROAD CYCLONIC TURNING IS ALONG THE WAVE AXIS NEAR 11N. SCATTERED MODERATE CONVECTION IS FROM 8N-12N BETWEEN 25W-31W. TROPICAL WAVE IS ALONG 51W/52W S OF 21N MOVING W NEAR 15 KT. SHOWER AND THUNDERSTORM ACTIVITY REMAINS DISORGANIZED IN ASSOCIATION WITH THIS TROPICAL WAVE. UPPER-LEVEL WINDS ARE UNFAVORABLE FOR DEVELOPMENT OF THIS SYSTEM. A CLUSTER OF MODERATE CONVECTION HAS DEVELOPED ON THE NORTHERN END OF THE WAVE AXIS FROM 17N-20N BETWEEN 46W-49W. TROPICAL WAVE IS ALONG 82W S OF 20W MOVING W 10-15 KT. SHOWER ACTIVITY REMAINS LIMITED IN ASSOCIATION WITH THIS WAVE. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N16W 8N25W 6N35W 7N50W 7N62W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER W AFRICA MOVING W ALONG THE IMMEDIATE COASTAL WATERS WITHIN 150 NM OF THE ITCZ AXIS. THIS ACTIVITY MAY BE ASSOCIATED WITH A NEW TROPICAL WAVE. SCATTERED MODERATE CONVECTION IS WITHIN 140 NM EITHER SIDE OF THE AXIS BETWEEN 30W-35W. DISCUSSION... GULF OF MEXICO... AS WAS PREDICTED BY THE COMPUTER MODELS...A CLOSED UPPER LOW IS CENTERED ALONG THE W COAST OF FLORIDA NEAR TAMPA COVERING THE EASTERN GULF AND THE STATE OF FLORIDA. A MID/UPPER LEVEL TROUGH EXTENDS ACROSS THE EASTERN US TO THIS LOW. NLY WINDS ON THE WEST SIDE OF THE LOW ARE ADVECTING VERY DRY AIR INTO THE E GULF. A 1012 MB SFC LOW CURRENTLY LOCATED OVER THE STRAITS OF FLORIDA IS INTERACTING WITH THIS UPPER LOW. THE SFC LOW IS EXPECTED TO MOVE W INTO GULF OF MEXICO THIS MORNING. THIS LOW PRES MAY DEVELOP INTO A SUBTROPICAL OR TROPICAL CYCLONE. FOR MORE DETAILS SEE SPECIAL FEATURE. AN UPPER RIDGE EXTENDS ACROSS THE W-CENTRAL GULF FROM THE YUCATAN PENINSULA TO THE COAST NEAR THE LOUISIANA/TEXAS BORDER. ANOTHER UPPER LOW IS INLAND OVER MEXICO NEAR 23N99W SPREADING MOISTURE THROUGH SOUTH-CENTRAL MEXICO... THE BAY OF CAMPECHE AND THE SW GULF. SFC RIDGING DOMINATES THE SE US AND THE NORTHERN GULF WATERS PRODUCING MODERATE NE TO E WINDS OF 15 TO 20 KT N OF 26N. AN EARLIER QUIKSCAT PASS CONFIRMED THESE WINDS...STRONGEST OVER THE NE CORNER OF THE GULF. A PATCH OF SHOWERS AND TSTMS IS NEAR 26N84W. WIDELY SCATTERED SHOWERS ARE SEEN OVER THE REMAINDER OF THE GULF. CARIBBEAN SEA... A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE CARIBBEAN SEA. AN UPPER RIDGE ANCHORED ON A HIGH OVER NICARAGUA COVERS THE NW CARIBBEAN ENHANCING SHOWER ACTIVITY OVER CENTRAL AMERICA. A WEAK SURFACE TROUGH IS BENEATH THIS UPPER RIDGE EXTENDING ALONG THE YUCATAN PENINSULA/NORTHERN GUATEMALA GENERATING SCATTERED SHOWERS AND TSTMS INLAND. A SECOND UPPER HIGH IS IN THE SE CARIBBEAN NEAR 12N62W COVERING THE REMAINDER OF THE AREA. IN BETWEEN... THERE IS AN UPPER TROUGH THAT EXTENDS ACROSS THE CENTRAL CARIBBEAN FROM HAITI TO E PANAMA. A SURFACE TROUGH EXTENDS FROM THE REMNANTS OF INGRID IN THE NE CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NORTHERN LEEWARD ISLANDS. SOME SHOWER ACTIVITY IS ALONG THE NORTHERN COAST OF CUBA ASSOCIATED WITH SFC LOW LOCATED OVER THE STRAITS OF FLORIDA. ATLANTIC OCEAN... A LARGE AREA OF DISTURBED WEATHER OVER THE WESTERN ATLANTIC... NORTHERN BAHAMAS...AND THE EAST COAST OF FLORIDA REMAINS THE MAIN FEATURE OF INTEREST IN THE ATLANTIC. REFER TO SPECIAL FEATURE FOR MORE DETAILS. THE UPPER LOW ALONG THE W COAST OF FLORIDA EXTENDS ACROSS THE FLORIDA PENINSULA AND THE W ATLC TO 75W. AN UPPER HIGH IS TO THE E NEAR 26N71W WITH THE RIDGE AXIS EXTENDING N TO BEYOND 32N67W. AN UPPER TROUGH ENTERS THE AREA NEAR 32N52W EXTENDING SW TO 22N66W. THERE ARE TWO UPPER LOWS EMBEDDED IN THIS TROUGH. ONE IS NEAR 25N63W...THE SECOND ONE IS NEAR 32N52W. A SURFACE TROUGH RELATED TO THIS UPPER TROUGH EXTENDS FROM 31N50W TO NEAR 25N60W. LOW TO MID CLOUDS WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE JUST E AND WITHIN 150 NM OF THE SURFACE TROUGH. THE REMNANT CIRCULATION OF INGRID IS ANALYZED AS A 1012 MB SURFACE LOW LOCATED JUST N OF THE LEEWARD ISLANDS NEAR 20N63W WITH A SURFACE TROUGH EXTENDING ALONG 62W/63W S OF 25N INTO THE NE CARIBBEAN. SCATTERED MODERATE CONVECTION IS JUST E OF THE SURFACE LOW FROM 19N-22N BETWEEN 60W-63W. AN UPPER RIDGE GENERALLY ALONG 15N COVERS THE TROPICAL ATLC. N OF THE RIDGE UPPER WLY FLOW DOMINATES THE REMAINDER OF THE FORECAST AREA E OF 40W. $$ GR