000 AXNT20 KNHC 212253 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... THE CENTER OF HURRICANE HELENE AT 21/2100 UTC IS NEAR 30.7N 56.8W. HELENE IS MOVING NORTH 12 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 972 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 70 KT WITH GUSTS TO 85 KT. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC OR THE PUBLIC ADVISORY UNDER MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NEAR THE CENTER FROM 29N-34N BETWEEN 53W-59W. A BAND OF SCATTERED MODERATE CONVECTION IS S OF THE CENTER FROM 27N-29N BETWEEN 53W-59W. ...TROPICAL WAVES... AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 36W SOUTH OF 19N MOVING WEST 10 TO 15 KT. A 1012 MB LOW PRESSURE CENTER FORMED ALONG THE WAVE NEAR 12N. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS IN CLUSTERS FROM 9N TO 20N BETWEEN 28W AND 36W. AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 47W/48W SOUTH OF 20N MOVING WEST 10 TO 15 KT. A 1010 MB LOW PRESSURE CENTER IS NEAR 12N ALONG THE WAVE. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS E OF THE WAVE AXIS FROM 15N-18N BETWEEN 29W-34W. SCATTERED MODERATE CONVECTION IS NEAR THE LOW CENTER FROM 13N-15N BETWEEN 35W-39W. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 10N14W 12N35W 12N50W 10N60W. SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF W AFRICA FROM 10N-12N BETWEEN 14W-16W. ISOLATED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 35W-39W. ...DISCUSSION... THE GULF OF MEXICO... A COLD FRONT EXTENDS FROM S FLORIDA TO THE E GULF OF MEXICO ALONG 25N80W 27N87W...AND CONTINUES AS A WARM FRONT TO SW LOUISIANA NEAR 30N93W. ISOLATED MODERATE CONVECTION IS ALONG THE COAST OF LOUISIANA FROM 28N-31N BETWEEN 88W-93W. THE REMAINDER OF THE GULF OF MEXICO HAS MOSTLY FAIR WEATHER. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE NORTH CENTRAL GULF OF MEXICO NEAR 27N90W WITH STRONG SUBSIDENCE EXCEPT NEAR THE CONVECTION MENTIONED ABOVE. EXPECT THE FRONT TO DISSIPATE...AND SLY FLOW TO PREVAIL...DUE TO HIGH PRESSURE RIDGING OVER THE NEXT 24 HOURS. THE TAIL END OF ANOTHER COLD FRONT IS ALSO FORECAST TO MOVE TO CENTRAL TEXAS. SCATTERED SHOWERS ARE POSSIBLE OVER THE N GULF DURING THE NEXT 24 HOURS. THE CARIBBEAN SEA... A WEAK 1015 MB HIGH IS CENTERED OVER W CUBA NEAR 23N81W. MODERATE TRADEWINDS ARE NOTED OVER THE CARIBBEAN SEA. SCATTERED MODERATE CONVECTION IS OFF THE COAST OF NICARAGUA FROM 12N-16N BETWEEN 80W-83W. PATCHES OF ISOLATED MODERATE CONVECTION ARE INLAND OVER CENTRAL AMERICA FROM PANAMA TO GUATEMALA. SIMILAR CONVECTION IS OVER INLAND HISPANIOLA...W CUBA...AND OVER JAMAICA FROM 18N-21N BETWEEN 70W-78W. IN THE UPPER LEVELS... AN UPPER LEVEL LOW IS CENTERED OVER THE CAYMAN ISLANDS NEAR 19N82W. AN UPPER LEVEL HIGH IS JUST E OVER THE CENTRAL CARIBBEAN NEAR 19N74W. THE E CARIBBEAN E OF 70W HAS NELY UPPER LEVEL FLOW WITH STRONG SUBSIDENCE. EXPECT MORE CONVECTION OVER THE W CARIBBEAN AND CENTRAL AMERICA OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... A COLD FRONT IS OVER THE W ATLANTIC THAT EXTENDS FROM BERMUDA TO S FLORIDA ALONG 32N64W 27N70W 25N80W. NO CONVECTION IS ALONG THE FRONT. HURRICANE HELENE IS WELL E OF BERMUDA NEAR 30.7N 56.8W. A 1023 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 37N40W. IN THE UPPER LEVELS... IMPRESSIVE OUTFLOW IS OVER HURRICANE HELENE ESPECIALLY N OF THE CENTER. A SMALL UPPER LEVEL LOW IS CENTERED NEAR 24N64W PRODUCING SOME SW SHEAR OVER HURRICANE HELENE. ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 25N41W. A LARGE HIGH IS CENTERED OVER THE CAPE VERDE ISLANDS NEAR 18N24W. $$ FORMOSA