000 AXNT20 KNHC 220007 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON AUG 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... TROPICAL DEPRESSION FOUR IS CENTERED NEAR 12.0N 22.6W 0R ABOUT 210 MILES SOUTH SOUTHEAST OF THE SOUTHERN MOST CAPE VERDE ISLANDS AT 22/0000 UTC MOVING WEST AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER HEADERS MIATCMAT4/WTNT24 NHC AND THE PUBLIC ADVISORY UNDER HEADERS MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. SATELLITE IMAGERY SHOWS WIDELY SCATTERED MODERATE CONVECTION NEAR THE CENTER FROM 10N-14N BETWEEN 21W-25W. A BAND OF SCATTERED MODERATE TO STRONG CONVECTION IS S OF THE CENTER FROM 7N-10N BETWEEN 21W-26W. A LARGE AREA OF DUST IS N AND W OF THE T.D... THAT USUALLY HAMPERS DEVELOPMENT. IT IS DIFFICULT TO DETERMINE HOW MUCH OF A FACTOR IT WILL BE. ...TROPICAL WAVES... TROPICAL WAVE IN THE E ATLC IS ALONG 43W S OF 19N MOVING W NEAR 20 KT. A 1011 MB LOW IS PLACED ON THE WAVE AXIS NEAR 10N. THIS SFC LOW IS VERY BROAD...BUT SFC OBS AND A QUIKSCAT PASS HAS HELPED LOCATE THE LOW CENTER. THE WAVE ITSELF IS ALSO BROAD...BUT IS HIGH AMPLITUDE WITH CYCLONIC TURNING COVERING A LARGE AREA ABOUT THE AXIS. AGAIN SAHARAN DUST SURROUNDS THE NRN EXTENSION OF THE WAVE. WIDELY SCATTERED MODERATE CONVECTION IS E OF THE WAVE AXIS FROM 10N-13N BETWEEN 38W-40W. SIMILAR CONVECTION IS W OF THE WAVE AXIS FROM 6N-10N BETWEEN 43W-46W. TROPICAL WAVE IS ABOUT 230 NM E OF BARBADOS ALONG 56W S OF 19N MOVING W 15-20 KT. WELL DEFINED WAVE STRUCTURE WITH AN INVERTED V-SHAPE IS EVIDENT ON SATELLITE IMAGERY. THIS WAVE ALSO APPEARS TO BE THE LEADING EDGE OF THE SAHARAN DUST. CONVECTION IS MOSTLY CONFINED TO THE ITCZ. SCATTERED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 52W-56W. TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 72W/73W S OF 18N MOVING W NEAR 15 KT. SCATTERED MODERATE CONVECTION IS OVER INLAND HISPANIOLA FROM 18N-20N BETWEEN 69W-73W. SIMILAR CONVECTION IS INLAND OVER NW VENEZUELA AND N COLOMBIA FROM 8N-11N BETWEEN 72W-75W. TROPICAL WAVE OVER CENTRAL AMERICA IS ALONG 88W S OF 18N MOVING W 10-15 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER THE YUCATAN PENINSULA FROM 16N-21N BETWEEN 87W-92W. SIMILAR CONVECTION IS OVER NICARAGUA AND HONDURAS FROM 12N-16N BETWEEN 82W-87W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 13N17W 10N27W 11N35W 9N45W 10N56W 9N60W. BESIDES CONVECTION MENTIONED IN THE SPECIAL FEATURE AND THE TROPICAL WAVES SECTIONS... SCATTERED MODERATE CONVECTION IS FROM 7N-10N BETWEEN 46W-50W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH IS OVER THE W GULF OF MEXICO ALONG 24N93W 19N94W. SCATTERED SHOWERS ARE FROM 20N-26N BETWEEN 90W-97W. SCATTERED MODERATE CONVECTION IS INLAND OVER CENTRAL FLORIDA FROM 26N-29N BETWEEN 80W-83W. SIMILAR CONVECTION IS INLAND FROM S LOUISIANA TO THE FLORIDA PANHANDLE FROM 30N-32N BETWEEN 84W-92W. IN THE UPPER LEVELS... AN UPPER LOW IS SPINNING IN THE SW GULF NEAR 22N95W. ANOTHER SMALL UPPER LOW IS OVER N FLORIDA NEAR 29N83W. CONSIDERABLE CLOUDINESS COVERS THE GULF OF MEXICO. LITTLE CHANGE IN THE WEATHER PATTERN IS EXPECTED OVER THE NEXT 24 HOURS. CARIBBEAN SEA... TWO TROPICAL WAVES ARE OVER THE CARIBBEAN AREA WITH ANOTHER APPROACHING. REFER TO THE TROPICAL WAVE SECTION ABOVE. IN ADDITION... SCATTERED MODERATE CONVECTION IS OVER CUBA AND THE NW CARIBBEAN FROM 18N-22N BETWEEN 74W-85W. FURTHER S...AN ACTIVE ITCZ WITH WIDELY SCATTERED MODERATE CONVECTION IS INLAND OVER SOUTH AMERICA ALONG 8N. IN THE UPPER LEVELS... AN UPPER LEVEL HIGH IS CENTERED NEAR JAMAICA AT 19N79W INFLUENCING THE CONVECTION OVER CUBA. ELY UPPER LEVEL FLOW IS OVER THE E CARIBBEAN E OF 70W. EXPECT THE TROPICAL WAVES TO MOVE W WITH CONVECTION DURING THE NEXT 24 HOURS. ALSO EXPECT THE ITCZ TO REMAIN ACTIVE. ATLANTIC OCEAN... A 1028 MB HIGH DOMINATES THE ATLANTIC NEAR 37N44W. A SMALL SURFACE TROUGH IS NE OF THE BAHAMAS HOWEVER...ALONG 28N65W 24N70W. SCATTERED MODERATE CONVECTION IS FROM 26N-28N BETWEEN 64W-67W. IN THE UPPER LEVELS... SEVERAL UPPER LEVEL LOWS ARE SEEN SPINNING IN WATER VAPOR IMAGERY ACROSS THE WRN AND CNTRL ATLC. THE WRN-MOST IS OVER N FLORIDA NEAR 29N83W. UPPER DIFFLUENCE ON THE S SIDE OF THE LOW IS PRODUCING SCATTERED SHOWERS AND TSTMS ACROSS THE BAHAMAS AND CENTRAL FLORIDA. ANOTHER UPPER LOW IS SE OF BERMUDA NEAR 30N61W. DIFFLUENT FLOW ON THE S AND E SIDE OF THE CIRCULATION IS PRODUCING PATCHES OF SHOWERS AND TSTMS. ANOTHER UPPER LOW IS NEAR 22N43W. THIS FEATURE IS EMBEDDED IN DRY AIR PRODUCING LITTLE WEATHER. THE E ATLC IS DOMINATED BY AN UPPER RIDGE WITH A HIGH CENTER NEAR 16N39W...THE RIDGE AXIS STRETCHES NE TO BEYOND 32N17W. DRY STABLE UPPER LEVEL AIR COVERS THE AREA UNDER THIS RIDGE. IN ADDITION TO THE DRY UPPER LEVEL AIR...WIDESPREAD SAHARAN DUST IN THE MID-LEVELS HAS SURGED OUT TO NEAR 60W BETWEEN 11N-25N. $$ FORMOSA