000 AXNT20 KNHC 191038 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURE... A WEAK SURFACE LOW PRESSURE AREA AND A UPPER-LEVEL LOW NEAR THE FLORIDA PENINSULA ARE PRODUCING A LARGE AREA OF DISTURBED WEATHER OVER THE WESTERN ATLANTIC...NORTHERN BAHAMAS...AND THE EAST COAST OF FLORIDA. THERE ARE NO SIGNS OF ORGANIZATION AT THIS TIME. HOWEVER...SURFACE PRESSURES ARE SLOWLY 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 ROTATING CYCLONICALLY MAINLY OVER NORTH-CENTRAL FLORIDA. SCATTERED SHOWERS ARE ALONG SOUTH FLORIDA EAST COAST. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 29W S OF 16N MOVING W 10-15 KT. THE WAVE HAS AN INVERTED-V PATTERN ON SATELLITE IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 10N-12N BETWEEN 25W-31W. TROPICAL WAVE IS ALONG 52W/53W S OF 21N MOVING W NEAR 15 KT. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH THIS FEATURE HAVE DIMINISHED. UPPER-LEVEL WINDS ARE UNFAVORABLE FOR DEVELOPMENT OF THIS SYSTEM. A CLUSTER OF MODERATE CONVECTION IS WITHIN 200 NM EAST OF THE WAVE AXIS FROM 18N-20N BETWEEN 46W-49W. TROPICAL WAVE IS ALONG 84W/85W S OF 20W MOVING W 10-15 KT. SHOWER ACTIVITY REMAINS LIMITED IN ASSOCIATION WITH THIS WAVE. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N15W 11N25W 6N35W 7N50W 7N62W. SCATTERED MODERATE CONVECTION IS INLAND OVER W AFRICA MOVING W ALONG THE IMMEDIATE COASTAL WATERS WITHIN 200 NM N OF THE ITCZ AXIS. THIS ACTIVITY MAY BE ASSOCIATED WITH A NEW TROPICAL WAVE. SCATTERED MODERATE CONVECTION IS FROM 4N-9N BETWEEN 31W-36W. DISCUSSION... GULF OF MEXICO... A CLOSED UPPER-LEVEL 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. DRY AIR WRAPPING AROUND THE LOW DOMINATES MOST OF THE EASTERN GULF...WESTERN CUBA AND SOUTH FLORIDA. A 1009 MB SFC LOW CURRENTLY LOCATED ENE OF MIAMI NEAR 26N79W IS INTERACTING WITH THIS UPPER LOW. THE SFC LOW IS EXPECTED TO MOVE W INTO GULF OF MEXICO TODAY. THIS LOW PRES AREA 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. UPPER DIFFLUENCE BETWEEN THIS UPPER LOW AND A RIDGE OVER THE YUCATAN PENINSULA/NORTHERN CENTRAL AMERICA IS HELPING TO INDUCE A LINE OF SHOWERS WITH ISOLATED TSTMS OVER THE SW GULF AND THE BAY OF CAMPECHE. 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 WHERE PRES GRADIENT TIGHTENS. 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 ISOLATED TSTMS INLAND. A SECOND UPPER HIGH IS IN THE SE CARIBBEAN NEAR 12N62W COVERING THE REMAINDER OF THE REGION. IN BETWEEN...THERE IS AN UPPER TROUGH THAT EXTENDS ACROSS THE CENTRAL CARIBBEAN FROM HISPANIOLA TO W PANAMA. MODERATE TO STRONG CONVECTION HAS FLARED UP NEAR THE COLOMBIA/PANAMA BORDER THANKS TO A DIFFLUENT PATTERN ALOFT AND THE PRESENCE OF THE EPAC ITCZ. A SURFACE TROUGH EXTENDS FROM THE REMNANTS OF INGRID IN THE NE CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NORTHERN LEEWARD ISLANDS. ATLANTIC OCEAN... A WEAK SURFACE LOW PRESSURE AREA AND AN UPPER-LEVEL LOW NEAR THE FLORIDA PENINSULA ARE PRODUCING A LARGE AREA OF DISTURBED WEATHER OVER THE WESTERN ATLANTIC...PORTIONS OF THE BAHAMAS...AND PORTIONS OF THE FLORIDA PENINSULA. THIS 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. A WEAK UPPER HIGH IS TO THE E NEAR 30N65W. AN UPPER TROUGH ENTERS THE AREA NEAR 31N53W EXTENDING SW TO 20N66W. THERE ARE TWO UPPER LOWS EMBEDDED IN THIS TROUGH. ONE IS NEAR 25N63W...THE SECOND ONE IS NEAR 31N53W. A SURFACE TROUGH RELATED TO THIS UPPER TROUGH EXTENDS FROM 30N50W 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 1011 MB SURFACE LOW NEAR 21N64W WITH A SURFACE TROUGH EXTENDING ALONG 63W/64W S OF 24N INTO THE NE CARIBBEAN. UPPER DIFFLUENCE ASSOCIATED WITH THE AFOREMENTIONED UPPER TROUGH IS SUPPORTING A LARGE CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION JUST EAST OF INGRID'S REMNANTS. 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