000 AXNT20 KNHC 062341 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED SEP 06 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... TROPICAL STORM FLORENCE IS CENTERED NEAR 19.0N 51.4W AT 06/2100 UTC MOVING WEST-NORTHWEST AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. AN UPPER LEVEL LOW IS TO THE NW OF FLORENCE PRODUCING SW UPPER SHEAR OVER THE SYSTEM. HOWEVER...THE LOW LEVEL CENTER IS EMBEDDED WITHIN THE CONVECTION THUS SHOWING SOME SIGNS OF ORGANIZATION. NUMEROUS STRONG CONVECTION IS WITHIN 45 NM OF LINE 19N49W-20.5N51W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE REMAINDER OF THE AREA WITHIN 150 NM OF LINE 14N48W-18N47W-22N52W. ...TROPICAL WAVES... TROPICAL WAVE WAS INTRODUCED ALONG 22W S OF 15N MOVING W 10-15 KT BASED ON SATELLITE IMAGERY AND UPPER AIR DATA FROM AFRICA OVER THE PAST FEW DAYS. WAVE IS LOW AMPLITUDE AND IN DRY AIR AND AFRICAN DUST THUS NO ASSOCIATED CONVECTION. TROPICAL WAVE IS ALONG 39W/40W S OF 20N WITH A WEAKENING 1012 MB LOW ALONG THE WAVE NEAR 16N MOVING W 10-15 KT. WAVE IS BECOMING ENTRAINED INTO TROPICAL STORM FLORENCE AND IS LOSING THE ROTATION ASSOCIATED WITH THE LOW. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF LINE 1938W-21N41W. TROPICAL WAVE IN THE E CARIBBEAN IS ALONG 69W S OF 20N MOVING W 15 KT. LOW LEVEL INVERTED-V SIGNATURE IS OBSCURED BY DENSE CLOUDS LAYERED THUS WAVE LOCATION IS BASED ON CONTINUITY. CONVECTION IN THE VICINITY IS ASSOCIATED WITH UPPER LEVEL FEATURES. TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 80W/81W S OF 19N MOVING W 10 KT. WEAK INVERTED-V SIGNATURE IS OBSERVED ON SATELLITE IMAGERY. CONVECTION IN THE VICINITY IS ASSOCIATED WITH UPPER LEVEL FEATURES. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 10N24W 14N37W BECOMING DISTORTED BY TROPICAL STORM FLORENCE THEN ALONG 15N55W 13N71W 9N79W ACROSS COSTA RICA NEAR 9N83W INTO THE E PACIFIC REGION. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MOVING OFF THE COAST OF AFRICA FROM 9N-12N E OF 16W TO JUST INLAND OVER AFRICA. ...DISCUSSION... GULF OF MEXICO... DEEP LAYERED TROUGH COVERING THE E HALF OF THE US DIPS S OVER THE GULF N OF 25N WITH THE ASSOCIATED FRONTAL BOUNDARY EXTENDING FROM THE NW ATLC THROUGH A DEVELOPING 1012 MB LOW OVER NE FLORIDA NEAR 30N82W TO 24N91W WHERE IT BEGINS TO PULL UP STATIONARY TO THE COAST OF MEXICO NEAR TAMPICO. UPPER RIDGE EXTENDS OVER THE SW GULF EXTENDING ACROSS MEXICO FROM THE E PACIFIC REGION. A BROAD UPPER RIDGE ANCHORED IN THE CARIBBEAN COVERS THE SE GULF. THIS SCENARIO IS GIVING THE ENTIRE GULF RATHER MOIST CONDITIONS THUS THE DEVELOPMENT OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE AREA WITH THE STRONGEST STORMS IN THE NE GULF AND OVER THE THE FLORIDA PENINSULA. CARIBBEAN SEA... BROAD UPPER RIDGE COVERS THE CARIBBEAN ANCHORED BY AN UPPER HIGH NEAR THE WINDWARD PASSAGE AND EXTENDS INTO THE SE GULF OF MEXICO AND COVER THE SW ATLC. A WEAK INVERTED UPPER TROUGH EXTENDS FROM OVER PANAMA TO NEAR 15N79W. GENERALLY MOIST CONDITIONS COVER THE CARIBBEAN WITH SOMEWHAT DRIER AIR OVER THE NW N OF 18N FROM 78W-86W. HOWEVER...AFTERNOON THUNDERSTORMS HAVE DEVELOPED OVER CUBA IN SPITE OF THE DRIER CONDITIONS. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS COVER MUCH OF THE REMAINDER OF THE CARIBBEAN WITH THE STRONGEST THUNDERSTORMS FROM OVER HISPANIOLA TO THE N LEEWARD ISLANDS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 10N FROM COLOMBIA TO COSTA RICA DUE TO THE ITCZ AXIS CROSSING THAT AREA. ATLANTIC OCEAN... BROAD DEEP LAYERED TROUGH OVER THE E US EXTENDS INTO THE W ATLC N OF 30N W OF 76W. THE ASSOCIATED COLD FRONT EXTENDS THROUGH A 1013 MB LOW LOCATED ALONG THE COAST OF GEORGIA INTO THE GULF OF MEXICO NEAR JACKSONVILLE FLORIDA. UPPER RIDGE ANCHORED IN THE CARIBBEAN COVERS THE REMAINDER OF THE W ATLC W OF 70W. THIS IS ENHANCING AFTERNOON THUNDERSTORMS OVER THE FLORIDA PENINSULA MOVING NE N OF 25N W OF 78W. AN AREA OF INTEREST IS JUST SE OF THE FRONTAL BOUNDARY WHERE A POSSIBLE DEVELOPING TROPICAL SYSTEM IS BEING MONITORED AND COVERS THE AREA WITH SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS N OF 30N FROM 72W-78W. AN UPPER LOW IS NE OF THE LEEWARD ISLANDS AND NW OF TROPICAL STORMS FLORENCE CENTERED NEAR 22N59W WITH THE UPPER TROUGH COVERING THE AREA FROM 50W-65W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 24N-28N BETWEEN 64W-69W. THIS UPPER LOW IS ENHANCING SHOWERS/ THUNDERSTORMS OVER THE LEEWARD/VIRGIN ISLANDS AND PRODUCING SHEAR OVER FLORENCE. AN UPPER HIGH IS CENTERED E OF FLORENCE AND THE TROPICAL WAVE ALONG 39W/40W NEAR 19N38W AND COVERS THE REMAINDER OF THE E ATLC. AT THE SURFACE...A RAPIDLY WEAKENING FRONT IS IN THE NE ATLC THROUGH 32N23W TO 28N28W AND A RIDGE AXIS ANCHORED BY A 1028 MB HIGH W OF THE AZORES NEAR 38N38W COVERING THE REMAINDER OF THE ATLC. MORE AFRICAN DUST IS MOVING INTO THE TROPICAL ATLC NOW FROM 13N-26N E OF 30W. $$ WALLACE