000 AXNT20 KNHC 180605 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI AUG 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 35W SOUTH OF 21N MOVING WEST NEAR 10 KT. CYCLONIC TURNING OF LOW LEVEL CLOUDS IS NOTED N OF THE ITCZ. THE ONLY CONVECTION NEAR THIS WAVE IS SCATTERED MODERATE...IN THE VICINITY OF THE ITCZ...FROM 10N-13N BETWEEN 32W-39W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 50W/51W SOUTH OF 20N MOVING WEST NEAR 15 KT. AN INVERTED-V LOW LEVEL CLOUD SIGNATURE IS NOTED IN THIS EVENINGS SHORTWAVE IR IMAGERY...THOUGH THE PATTERN IS NOT AS CLEAR TONIGHT DUE TO HIGH CLOUDS STREAMING SW TO NE OVER THE AREA EAST OF AN UPPER LOW. SCATTERED SHOWERS AND TSTMS LIE NEAR THE NRN PORTION OF THE WAVE AXIS FROM 18N-23N BETWEEN 51W-56W...AS THE WAVE INTERACTS WITH THE UPPER LOW. THE ONLY OTHER REGION OF CONVECTION NOTED IS CONFINED TO THE ITCZ WITH SCATTERED MODERATE CONVECTION FROM 7N-11N BETWEEN 45W-55W. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 83W SOUTH OF 22N MOVING WEST 10 TO 15 KT. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE OVER CUBA AND THE ADJACENT WATERS FROM 18N-24N BETWEEN 75W-83W. SCATTERED MODERATE CONVECTION IS ALSO OVER WRN HONDURAS AND NICARAGUA. TWO CLUSTERS OF MODERATE TO STRONG CONVECTION ARE IN THE SRN CARIBBEAN N OF PANAMA FROM 9N-12N BETWEEN 75W-80W...BUT THIS MAY BE MORE ASSOCIATED WITH THE ITCZ. ISOLATED SHOWERS AND TSTMS ARE NOTED ELSEWHERE WITHIN 200NM OF EITHER SIDE OF THE AXIS. ...THE ITCZ... ITCZ IS CENTERED ALONG 10N14W 11N34W 11N37W 10N50W TO INLAND OVER SOUTH AMERICA NEAR 9N72W. A COUPLE CLUSTERS OF MODERATE CONVECTION ARE OFF THE AFRICAN COAST FROM 5N-10N BETWEEN 14W AND 21W. THERE ALSO APPEARS TO BE SOME BROAD CYCLONIC TURNING IN THIS REGION. THIS ALONG WITH ANALYSIS OF THE HOVMOLLER DIAGRAMS ON THE TAFB WEBSITE SUGGEST A DEVELOPING TROPICAL WAVE MAY BE MOVING OFF OF AFRICA. WIDELY SCATTERED MODERATE CONVECTION LIES FROM 9N-14N BETWEEN 32-42W...AND FROM 6N-12N BETWEEN 44W-57W. TWO CLUSTERS OF MODERATE TO STRONG CONVECTION ARE IN THE SRN CARIBBEAN N OF PANAMA FROM 9N-12N BETWEEN 75W-80W. ...DISCUSSION... THE GULF OF MEXICO... THE MAIN FEATURE IN THE GULF THIS EVENING IS A MID TO UPPER LEVEL LOW MOVING INTO THE WRN PORTION...CENTERED NEAR 24N92W. INSTABILITY AROUND THE BASE OF THE UPPER TROUGH...ALONG WITH UPPER DIFFLUENCE BETWEEN THE UPPER LOW AND THE UPPER HIGH OVER TEXAS IS PRODUCING A COUPLE SMALL CLUSTERS OF MODERATE CONVECTION OFF OF THE NE MEXICO/S TX COAST...FROM 24N-27N BETWEEN 94W-97W. ISOLATED SHOWERS AND TSTMS ARE IN THE ERN GULF PUSHING WSW AROUND THE SE PORTION OF AN UPPER ANTICYCLONE NEAR MEMPHIS TENNESSEE. AT THE SURFACE...A WEAK 1011MB LOW IS LOCATED NEAR 24N90W. THIS FEATURE IS SUBTLE AND APPEARS TO BE TRANSITIONING INTO A TROUGH WITHOUT A CLOSED LOW LEVEL CENTER. QUIKSCAT DATA JUST AFTER 0000 UTC SUGGESTS THIS AS WELL. THE SHOWERS AND TSTMS JUST OFF NE MEXICO/EXTREME SRN TEXAS WILL GRADUALLY PUSH INLAND OVER THE NEXT 24-36 HRS...WHILE THE ISOLATED SHOWERS/TSTMS IN THE ERN GULF ALSO MOVE W THROUGH THE NRN PORTION OF THE GULF. THE CARIBBEAN SEA... THE MOST SIGNIFICANT WEATHER IN THE CARIBBEAN ARE THE TWO CLUSTERS OF MODERATE TO STRONG CONVECTION JUST N AND NE OF THE PANAMA COAST. THERE ARE STILL SIGNS OF BROAD MID TO UPPER LEVEL CYCLONIC MOTIONS IN THE NW CARIBBEAN...BUT IT IS DIFFICULT TO LOCATE AN UPPER LOW CENTER ON WV IMAGERY. THE ERN PORTION OF A DISTINCT UPPER HIGH OVER GUATEMALA IS EXTENDING INTO THE WRN CARIBBEAN WITH THE AXIS MORE OR LESS ALONG 14N OUT TO 80W. MID TO UPPER LEVEL W/WSW FLOW IS DOMINATING THE CENTRAL AND ERN CARIBBEAN TONIGHT...FEEDING INTO THE LARGE UPPER LOW NE OF THE LEEWARD ISLANDS. THIS IS BLOWING OFF THE TOPS OF THE CONVECTION ALONG THE ITCZ OVER SOUTH AMERICA...WITH SOME SCATTERED SHOWERS AND TSTMS SPILLING OVER INTO THE SRN CARIBBEAN FROM 11N-14N BETWEEN 61W-76W. AT THE SURFACE...A TROPICAL WAVE IS MOVING THROUGH THE WRN CARIBBEAN. ASSOCIATED SHOWER/TSTM ACTIVITY WILL CONTINUE PUSHING THROUGH CENTRAL AMERICA. THE SW PORTION OF THE ATLC HIGH IS INTERACTING WITH A 1006 MB COLOMBIAN LOW...PRODUCING 15-20 KT TRADES OVER MUCH OF THE CARIBBEAN. THE ATLANTIC OCEAN... THE SURFACE LOW PRESSURE AREA JUST OFFSHORE SAVANNAH GEORGIA IS BECOMING LESS ORGANIZED AND HAS LIMITED SHOWER AND TSTM ACTIVITY. THE MOST SIGNIFICANT CONVECTION ASSOCIATED WITH THIS SYSTEM IS A SMALL CLUSTER OF SCATTERED MODERATE CONVECTION ABOUT 80NM E OF JACKSONVILLE FLORIDA. UW-CIMMS SHEAR ANALYSIS DEPICTS 20 TO 30 KTS OF NORTHERLY SHEAR OVER THIS REGION...AND UPPER LEVEL WINDS ARE EXPECTED TO BECOME EVEN MORE UNFAVORABLE FOR DEVELOPMENT DURING THE DAY TODAY. HOWEVER...SHOWERS ND TSTMS WITH BRIEF GUSTY WINDS COULD STILL AFFECT COASTAL AREAS OF EXTREME SOUTHERN SOUTH CAROLINA...GEORGIA...AND NORTHEASTERN FLORIDA DURING THE NEXT DAY OR SO AS THE SYSTEM DRIFTS SOUTHWESTWARD. ISOLATED SHOWERS AND TSTMS ARE SEEN E OF THE BAHAMAS FROM 24N-29N BETWEEN 67W-73W. THIS APPEARS TO BE ASSOCIATED WITH UPPER DIFFLUENCE ALONG WITH PERHAPS SOME WEAK SURFACE TROUGHING. JUST TO THE E OF THIS AREA LIES SCATTERED SHOWERS AND TSTMS FROM 20N-30N BETWEEN 52W-62W. THERE IS A WELL DEFINED UPPER LOW IN THIS VICINITY...WITH THE CENTER NEAR 22N63W. MUCH OF THE CENTRAL AND ERN ATLC FROM 15N-30N BETWEEN THE COAST OF AFRICA AND 50W IS DOMINATED BY A PAIR OF UPPER HIGHS...FAIR WEATHER...AND WEAK SURFACE HIGH PRESSURE. BETWEEN THE UPPER HIGHS...THERE IS A NARROW UPPER TROUGH AXIS EXTENDING N/S ALONG 38W. THERE IS A WEAK REFLECTION OF THIS TO THE SURFACE AS VERIFIED BY AN EARLIER QUIKSCAT PASS AND LOW CLOUD MOTIONS...THOUGH SHOWER AND TSTM ACTIVITY ASSOCIATED WITH THIS FEATURE IS MINIMAL. $$ WILLIS