000 AXNT20 KNHC 190003 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED OCT 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...TROPICAL WAVE... AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ADDED ALONG 32W S OF 19N ESTIMATED TO BE MOVING W 5 TO 10 KT. THIS IS SLIGHTLY W OF WHAT SEEMS TO BE MORE OF A MID LEVEL CIRCULATION CENTERED AROUND 14N30W. I WAS RELUCTANT TO PUT THIS FEATURE ON THE MAP LAST EVENING AS THE METEOSAT 8 HOVMOLLER DIAGRAM SHOWED LITTLE WESTWARD MOTION. HOWEVER...TODAYS HOVMOLLER ANALYSIS SHOWS IT HAS BEGUN TO MOVE SLOWLY TO THE W. THE EXACT AXIS LOCATION IS A LITTLE UNCLEAR BUT ENOUGH TURNING OF THE LOW CLOUD FIELD EXISTS TO WARRANT A WAVE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-18N BETWEEN 30W-35W...AND FROM 9N-13N BETWEEN 26N-31W. SW SHEAR ESPECIALLY OVER THE NORTHERN PORTION OF THE WAVE CONTINUES TO STRETCH THE ASSOCIATED HIGH CLOUDS TO THE NE. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 42W SOUTH OF 21N MOVING WEST AT 15 KT. CYCLONIC TURNING/INVERTED V REMAINS EVIDENT IN THE LOW CLOUD FIELD. DEEP CONVECTION REMAINS MINIMAL WITH ISOLATED SHOWERS/TSTMS NOTED WITHIN 150NM OF THE AXIS FROM 10N-15N. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N13W 10N30W 10N40W 8N50W 7N60W. OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS OVER WRN AFRICA AND THE ADJACENT ERN ATLC WATERS FROM 8N-12N BETWEEN 11W-16W. A SMALL CLUSTER OF MODERATE CONVECTION NOTED NEAR 8N23W. SCATTERED MODERATE CONVECTION FROM 4N-9N BETWEEN 37W-40W. OTHER CLUSTERS OF MODERATE CONVECTION ARE MOVING NE FROM S AMERICA INTO THE ATLC FROM 4N-7N BETWEEN 51W-58W. ...DISCUSSION... GULF OF MEXICO... LINE OF SHOWERS/TSTMS THAT IS HUGGING FLORIDA PANHANDLE...NRN GULF...AND BIG BEND AREA HAS BEEN LOSING ITS IDENTITY OVER THE LAST 24 HRS. THE OPPOSITE CAN BE SAID FOR THE CONVECTION OVER ERN TEXAS AND LOUISIANA ASSOCIATED WITH THE UNSTABLE ENVIRONMENT S OF A STATIONARY FRONT...THOUGH THIS IS NOT EFFECTING THE GULF. A PRONOUNCED UPPER HIGH CONTINUES TO DOMINATE THE GULF THIS EVENING...WITH AN ESTIMATED CENTER NEAR 26N91W. THIS ALONG WITH FAIRLY DRY MID TO UPPER LEVEL AIR IS HELPING TO PRODUCE ABUNDANT FAIR WEATHER ACROSS THE GULF ASIDE FROM THE DIMINISHING LINE OF SHOWERS IN THE NE PORTION. GENTLE 5 TO 10KT ANTICYCLONIC FLOW FOUND AT THE SURFACE IN THE ERN GULF AROUND THE SW PORTION OF AN ATLC RIDGE. 10 TO 15 KT SE FLOW IN THE WRN PORTION AS THIS HIGH INTERACTS WITH LOWER PRESSURE OVER MEXICO. COLD FRONT EXPECTED TO ENTER THE NW GULF TOMORROW WITH N/NE FLOW INCREASING OFF THE TEXAS COAST INTO TOMORROW EVENING...SEE MIAOFFNT4 FOR DETAILS. CARIBBEAN SEA... NE/ENE FLOW AROUND THE UPPER HIGH OVER THE GULF DOMINATES THE GULF W OF 70W THIS EVENING...ACCOMPANIED BY DRY MID TO UPPER AIR AND LOTS OF FAIR WEATHER. THE SURFACE PATTERN IN THIS VICINITY IS A BIT MORE COMPLEX. THERE ARE NUMEROUS LOW LEVEL VORTICITY MAXIMUMS SEEN IN THE CENTRAL CARIBBEAN FROM 10N-18N BETWEEN 70W-83W. INSTEAD OF SPLATTERING THE 1800 UTC MAP WITH TONS OF SURFACE LOWS HAVE OPTED TO WAIT FOR MORE CONFIRMATION FROM THE AVAILABLE BUOY AND SHIP OBSERVATIONS. NONETHELESS SOME ADJUSTMENTS WILL LIKELY BE NEEDED FOR THE 0000 UTC MAP. MOST OF THESE LOW LEVEL CENTERS SEEM TO BE ORIENTED ALONG SOME SORT OF BOUNDARY ON THE EDGE OF A REBUILDING ATLC RIDGE FROM THE NE. IN THE ERN CARIBBEAN...A SURFACE TROUGH EXTENDS SSW TO THE ABC ISLANDS FROM A 1006MB SURFACE LOW ABOUT 100NM N OF RINCON PUERTO RICO. MOST OF THE ASSOCIATED CONVECTION IS CONFINED TO PUERTO RICO...THE VIRGIN ISLANDS...AND THE ATLC WATERS TO THE N. UPPER WESTERLY FLOW IS OVER THIS AREA S OF AN UPPER LOW NE OF THE LEEWARD ISLANDS. ATLANTIC OCEAN... NORTHERLY UPPER FLOW DOMINATES THE WRN ATLC W OF 65W AROUND THE PRONOUNCED UPPER HIGH FROM THE GULF. THIS REGION ALSO DOMINATED BY LOW LEVEL ANTICYCLONIC FLOW AROUND THE SW PORTION OF A 1020 MB SURFACE HIGH JUST S OF NEWFOUNDLAND. LOW LEVEL CONFLUENCE BETWEEN THIS HIGH AND THE 1017MB CENTRAL ATLC SFC HIGH NEAR 27N39W IS HELPING TO SUPPORT THE TROUGH EXTENDING NE FROM THE SURFACE LOW N OF PUERTO RICO ALONG 21N67W 30N51W. THERE IS ALSO AN UPPER LOW IN THIS VICINITY NEAR 25N58W. THE MOST SIGNIFICANT CONVECTION ASSOCIATED WITH THESE FEATURES IS THE NUMEROUS MODERATE/ISOLATED STRONG ACTIVITY E OF THE SURFACE LOW N OF PUERTO RICO...FROM 17N-23N BETWEEN 62W-67W. SCATTERED SHOWERS AND TSTMS ALSO SEEN SPINNING AROUND THE UPPER LOW FROM 16N-29N BETWEEN 50W-58W. STRONG UPPER WLY FLOW IS OVER THE TROPICAL NORTH ATLC WATERS E OF THE WINDWARD ISLANDS S OF THE UPPER LOW AND N OF A UPPER HIGH OVER S AMERICA. THERE IS A SHORT WAVE UPPER RIDGE ALONG 46W THEN A SHORTWAVE TROUGH JUST TO ITS E IN THE MIDST OF DRY AIR. ANOTHER UPPER HIGH NOTED NEAR 30N32W. THE FAR ERN ATLC DOMINATED BY A TROF EXTENDING SW FROM THE DEEP LAYER LOW N OF NW SPAIN THAT HAS A WEAK SURFACE REFLECTION ALONG 30N18W 28N34W...THAT HAS A DRY 1014 SFC LOW IN THE MIDDLE OF THOSE POINTS NEAR 29N24W. S OF THIS TROUGHING...UPPER RIDGING CONTINUES TO EXTEND W FROM AFRICA. OVERALL SIMILAR CONDITIONS EXPECTED THROUGH 24HRS WITH THE LOW N OF PUERTO RICO DRIFTING TO THE WNW. GFS SUGGESTS THIS LOW WILL DEEPEN SLIGHTLY BUT TROPICAL CYCLONE FORMATION IS NOT EXPECTED. $$ WILLIS