000 AXNT20 KNHC 211043 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... HURRICANE HELENE IS CENTERED NEAR 28.4N 56.8W OR ABOUT 478 MILES EAST-SOUTHEAST OF BERMUDA AT 21/0900 UTC MOVING NORTH AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 964 MB. MAXIMUM SUSTAINED WIND SPEED IS 80 KT WITH GUSTS TO 100 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE AREA FROM 27N-30N BETWEEN 55W-58W. DENSE OVERCAST CLOUDS COVERS A MUCH LARGER AREA FROM 26N-33N BETWEEN 53W-62W. ...TROPICAL WAVES... TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS ALONG 33W S OF 19N MOVING W 15-20 KT. BROAD MID LEVEL INVERTED-V CURVATURE WITH A LARGE AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 13N-19N BETWEEN 26W-37W. TROPICAL WAVE IS ALONG 48W/49W S OF 18N MOVING W 15 KT. INVERTED-V SIGNATURE WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION E OF THE WAVE AXIS WITHIN 60 NM OF LINE 13N42W-16N45W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 13N14W 11N23W 13N31W 12N40W 14N51W 11N62W ACROSS N PORTION OF SOUTH AMERICA AND PANAMA INTO THE E PACIFIC REGION NEAR 9N83W. SCATTERED CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N-15N E OF 27W TO THE COAST OF AFRICA AND FROM 8N-13N BETWEEN 33W-38W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE ANCHORED ALONG THE W COAST OF MEXICO COVERS ALL OF MEXICO WITH A RIDGE AXIS EXTENDING NE MOVING JUST E OF THE MISSISSIPPI VALLEY AND A SECOND RIDGE AXIS EXTENDING E OVER THE GULF ALONG 24N TO 86W. DEEP LAYER TROUGH OVER THE FAR E US AND THE W ATLC EXTENDS S OVER THE E GULF N OF 24N E OF 85W WITH THE ASSOCIATED STATIONARY FRONT ENTERING THE GULF OVER S FLORIDA NEAR LAKE OKEECHOBEE TO 26N86W WHERE IT BEGINS TO DISSIPATE ACROSS THE REMAINDER OF THE GULF. ISOLATED SHOWERS ARE WITHIN 90 NM OF THE FRONTAL BOUNDARY. DIFFLUENCE OVER THE BAY OF CAMPECHE IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS S OF 20N TO INLAND OVER S MEXICO FROM 92W-95W. CARIBBEAN SEA... AN UPPER LOW IS IN THE W CARIBBEAN NEAR 18N83W WITH A TROUGH EXTENDING TO CENTRAL CUBA NEAR NEAR 23N80W AND SW TO OVER HONDURAS NEAR 15N86W. THIS IS GENERATING SCATTERED SHOWERS/ THUNDERSTORMS OFF THE COAST OF NICARAGUA FROM 13N-16N BETWEEN 77W-83W. UPPER HIGH COVERS THE REMAINDER OF THE CARIBBEAN ANCHORED JUST S OF HAITI NEAR 17N74W THUS LEAVING THE CARIBBEAN E OF 77W DRY THIS MORNING. ATLANTIC OCEAN... BROAD UPPER TROUGH OVER THE FAR E US AND THE GULF OF MEXICO COVERS THE W ATLC N OF A LINE FROM FLORIDA NEAR 25N80W TO BEYOND 32N70W WITH THE ASSOCIATED COLD FRONT ENTERING THE AREA NEAR 32N69W SW TO THE BAHAMAS NEAR 27N78W WHERE IT PULLS UP STATIONARY ACROSS FLORIDA INTO THE GULF OF MEXICO NEAR LAKE OKEECHOBEE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90 NM E OF THE COLD FRONT N OF 28N. AN UPPER RIDGE IS ANCHORED E THE BAHAMAS NEAR 24N70W EXTENDING A RIDGE AXIS NE TO BEYOND 32N67W. UPPER HIGH ASSOCIATED WITH HURRICANE HELENE COVERS AN AREA FROM 23N-40N BETWEEN 50W-64W. NARROWING CUT-OFF UPPER LOW E OF HELENE IS BEING COMPRESSED BY THE UPPER HIGH OFF THE COAST OF AFRICA AND IS CENTERED NEAR 22N38W EXTENDING A TROUGH AXIS NE/SW FROM 27N33W-19N42W. UPPER HIGH ANCHORED NE THE CAPE VERDE ISLANDS NEAR 19N20W COVERS THE REMAINDER OF THE E ATLC. AT THE SURFACE...A 1022 MB HIGH IS LOCATED NEAR 29N41W WITH A RIDGE EXTENDING S TO 20N FROM 20W-50W. THIS AREA REMAINS VERY DRY THIS MORNING. $$ WALLACE