000 AXNT20 KNHC 201749 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN AUG 20 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS IN THE E ATLC ALONG 32W S OF 20N MOVING W 20 KT. THE SFC LOW THAT WAS PREVIOUSLY ANALYZED ON THIS WAVE HAS BEEN DROPPED AS THE CIRCULATION APPEARS TO HAVE OPENED. BROAD LOW-MID LEVEL TURNING IS NOTED ABOUT THE WAVE AXIS. THIS WAVE IS EMBEDDED IN A REGION OF SAHARAN DUST WHICH IS LIKELY LIMITING ANY CONVECTION NEAR THE AXIS N OF 11N. SCATTERED MODERATE CONVECTION IS EMBEDDED IN THE ITCZ FROM 5N-11N BETWEEN 28W-40W. TROPICAL WAVE IS IN THE CNTRL ATLC ALONG 47W S OF 19N MOVING W 15-20 KT. THIS WAVE HAS THE STRUCTURE OF A SURGE AND APPEARS TO BE JUST THAT AS SAHARAN DUST IS WIDESPREAD BEHIND THE ANALYZED AXIS. SIMILARLY TO THE WAVE IN THE E ATLC...SHOWERS AND TSTMS ARE CONFINED TO THE ITCZ FROM 7N-11N BETWEEN 43W-52W. TROPICAL WAVE IS IN THE E CARIBBEAN ALONG 66W S OF 18N MOVING W 10-15 KT. WEAK WAVE SIGNATURE IS NOTED IN THE AREA. ONLY ISOLATED SHOWERS ARE WITHIN 300 NM EITHER SIDE OF THE WAVE AXIS. MORE NUMEROUS SHOWERS EXTEND TO THE N OF THE WAVE IN THE ATLC ANALYZED AS A SFC TROF. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 10N34W 9N46W 8N59W ACROSS THE N PORTION OF SOUTH AMERICA AND PANAMA INTO THE E PACIFIC REGION. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES....SCATTERED MODERATE IS E OF 18W FROM 7N-13N. THIS ACTIVITY IS AHEAD OF THE NEXT TROPICAL WAVE TO MOVE OFF THE COAST OF AFRICA...THE AXIS IS WELL-DEFINED CURRENTLY ALONG 13W/14W. SCATTERED SHOWERS AND TSTMS ARE FROM 8N-11N BETWEEN 56W-60W. ...DISCUSSION... GULF OF MEXICO... SCATTERED SHOWERS AND TSTMS HAVE BECOME MORE WIDESPREAD LATE THIS MORNING AND EARLY AFTERNOON IN THE SE GULF FROM 24N-27N E OF 86W ACROSS S FLORIDA. THIS ACTIVITY IS MAINLY TRIGGERED BY UPPER DIFFLUENCE ON THE S SIDE OF AN UPPER LOW CENTERED ABOUT 150 NM ESE OF TAMPA. A SMALLER DRIER UPPER LOW IS LOCATED IN THE W BAY OF CAMPECHE NEAR 21N97W. THE N CENTRAL AND WRN GULF IS COVERED BY A SPRAWLING MID-UPPER RIDGE ACROSS THE SRN U.S. AT THE SFC...A TROF EXTENDS FROM A 1013 MB LOW OVER SRN GEORGIA ACROSS THE FL PANHANDLE TO 28N90W. ISOLATED TO SCATTERED SHOWERS HAVE DEVELOPED WITHIN 60 NM OF THE BOUNDARY...ESPECIALLY NEAR THE E GULF UPPER LOW. OTHERWISE...A WEAK PRES PATTERN LIES IN THE REGION KEEPING WINDS LIGHT AND VARIABLE. LITTLE CHANGE IN THE PRES PATTERN IS EXPECTED OVER THE NEXT FEW DAYS. THE GREATEST CHANCE OF RAIN WILL CONTINUE TO BE IN THE E GULF THRU THE DAY AND TONIGHT. GFS INDICATES TROPICAL MOISTURE CURRENTLY IN THE SW CARIBBEAN MOVING INTO THE SE GULF ON TUE. CARIBBEAN SEA... THE MOST ACTIVE WEATHER IN THE AREA IS IN THE SW CARIBBEAN WHERE NUMEROUS SHOWERS AND TSTMS HAVE DEVELOPED FROM 11N-17N BETWEEN 77W-81W. THIS ACTIVITY IS HIGHLY CONTRIBUTED TO UPPER DIFFLUENCE AT THE BASE OF A BROAD UPPER TROUGH IN THE WRN CARIBBEAN. A SFC TROUGH OR TROPICAL WAVE WILL BE ADDED TO THE 18Z MAP TO REFLECT WIND SHIFTS IN THE VICINITY SEEN AT THE SFC. SCATTERED SHOWERS AND TSTMS EXIST FROM 18N-20N BETWEEN 77W-84W. THE TROPICAL WAVE IN THE ERN CARIBBEAN IS PRODUCING VERY LITTLE SHOWER ACTIVITY...IN FACT BESIDES FOR THE CONVECTION OUTLINED ONLY ISOLATED TO SCATTERED SHOWERS DOT THE REMAINDER OF THE CARIBBEAN. IN THE UPPER LEVELS...A RIDGE COVERS THE ERN AND CENTRAL CARIBBEAN WITH WIDESPREAD DRY STABLE AIR E OF 62W. TRADE WINDS ARE GENERALLY 15-20 KT ACROSS THE SEA WITH THE STRONGEST WINDS FROM 12N TO 17N BETWEEN 68W AND 77W. GFS INDICATES TRADES INCREASING SLIGHTLY AND EXPANDING W OVER THE NEXT COUPLE OF DAYS. THE DEEP MOISTURE IN THE SW CARIBBEAN WILL MOVE TO THE WNW AT 10-15 KT...WHILE THE TROPICAL WAVE IN THE CNTRL ATLC INCREASES MOISTURE TO THE ERN ISLANDS LATE TUE. ATLANTIC OCEAN... AN ILL-DEFINED UPPER LEVEL PATTERN LIES ABOVE THE WRN AND CNTRL ATLC WITH SEVERAL UPPER LOWS EMBEDDED. THE WRN-MOST UPPER LOW IS CENTERED N OF THE BAHAMAS NEAR 28N78W. UPPER DIFFLUENCE ON THE S SIDE OF THE CIRCULATION IS ENHANCING SCATTERED SHOWERS AND TSTMS ACROSS THE W BAHAMAS W TO THE E GULF. ANOTHER UPPER LOW IS CENTERED 300 NM SE OF BERMUDA NEAR 30N61W. THIS UPPER LOW HAS A SFC REFLECTION AS A TROF ALONG 21N64W 29N55W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE MAINLY WITHIN 180 NM EITHER SIDE OF THE TROF AXIS. ANOTHER UPPER LOW IS IN THE CNTRL ATLC NEAR 23N42W. THIS FEATURE IS RATHER DRY PRODUCING LITTLE WEATHER. THE E ATLC IS COVERED BY A MID-UPPER RIDGE WITH THE HIGH CENTER N OF THE CAPE VERDE ISLANDS NEAR 23N21W WITH RIDGING EXTENDING SW TO 12N33W. MODERATE TO STRONG SUBSIDENCE LIES UNDER THE RIDGE. A SHIELD OF SAHARAN DUST LIES ACROSS THE ATLC E OF 48W FROM 11N-25N...BEHIND THE CNTRL ATLC TROPICAL WAVE BASED UPON THE HAZY LOOK ON VISIBLE IMAGES AND CIMSS SAL TRACKING PRODUCT. IT IS TYPICAL FOR WAVES TO ACT HAS LEADING EDGES OF DUST OUTBREAKS. AT THE SFC...A SURFACE RIDGE DOMINATES THE ATLC WITH THE SURFACE HIGHS N OF THE REGION. $$ CANGIALOSI