Update: Invest 94L/TD9 now TS Isaac: may threaten Cayman Islands
Further update: Now tropical Storm Isaac
000 WTNT34 KNHC 212050 TCPAT4 BULLETIN TROPICAL STORM ISAAC ADVISORY NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 500 PM AST TUE AUG 21 2012 ...AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT FINDS THAT THE DEPRESSION HAS BECOME A TROPICAL STORM... SUMMARY OF 500 PM AST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...15.4N 53.9W ABOUT 500 MI...810 KM E OF GUADELOUPE MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 17 MPH...28 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MARTINIQUE * DOMINICA * GUADELOUPE AND THE SURROUNDING ISLANDS...AND ST. MARTIN * ST. KITTS...NEVIS...ANTIGUA...MONTSERRAT...ANGUILLA...AND BARBUDA * SABA...ST. EUSTATIUS...AND ST. MAARTEN A TROPICAL STORM WATCH IS IN EFFECT FOR... * BRITISH VIRGIN ISLANDS * PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS. INTERESTS ELSEWHERE IN HISPANIOLA AND CUBA SHOULD MONITOR THE PROGRESS OF ISAAC. FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 15.4 NORTH...LONGITUDE 53.9 WEST. ISAAC IS MOVING TOWARD THE WEST NEAR 17 MPH...28 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST TRACK...THE CENTER OF ISAAC SHOULD MOVE THROUGH THE CENTRAL LESSER ANTILLES WEDNESDAY EVENING...AND EMERGE OVER THE EASTERN CARIBBEAN SEA BY THURSDAY MORNING. REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH HIGHER GUSTS. ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM TO THE NORTHEAST OF THE CENTER. THE MINIMUM CENTRAL PRESSURE JUST MEASURED BY THE HURRICANE HUNTER AIRCRAFT IS 1006 MB...29.71 INCHES. HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE WARNING AREA BY WEDNESDAY AFTERNOON...MAKING OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS. RAINFALL...TOTAL RAIN ACCUMULATIONS OF 4 TO 8 INCHES ARE POSSIBLE OVER THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS. TOTAL RAIN ACCUMULATIONS OF 1 TO 3 INCHES WITH MAXIMUM AMOUNTS OF 6 INCHES ARE POSSIBLE OVER PUERTO RICO AND THE VIRGIN ISLANDS. STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS IN THE NORTHERN LEEWARD ISLANDS. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY DANGEROUS WAVES. SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL AFFECT THE WINDWARD AND LEEWARD ISLANDS DURING THE NEXT COUPLE OF DAYS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE FOR MORE INFORMATION. NEXT ADVISORY ------------- NEXT INTERMEDIATE ADVISORY...800 PM AST. NEXT COMPLETE ADVISORY...1100 PM AST.
For latest advisories go to http://www.nhc.noaa.gov
Update to our story today (21) “Invest 94L may affect Cayman Islands as a TS on Saturday (25)”
By Bob Lightbown of crownweather.com
Tropical Depression #9: Invest 94L fired enough deep convection during the overnight hours to be considered a tropical depression, therefore, the National Hurricane Center has upgraded Invest 94L to Tropical Depression #9. TD 9 seems to be tracking a little south of due west at a forward speed of 18 to 19 mph. This system is currently located to the south of a west-southwest to east-northeast oriented high pressure system and this should keep TD 9 on a general westward track for the rest of this week. This track will bring TD 9 directly over the island of Dominica on Wednesday afternoon as a 50 to 60 mph tropical storm.
Once in the Caribbean, the track of TD 9/Isaac will be influenced by that high pressure ridge. Most of the forecast guidance show a track across the northern Caribbean, however, I think this may be too far of a north track, especially considering the depression’s current slightly south of due west track. Even the latest GFS model, which takes this system across central Cuba and then rakes all of Florida’s east coast before landfalling in eastern Georgia, seems a little too far north.
So, I’m leaning closer to the European model guidance track which takes TD 9/Isaac right across the islands of Guadeloupe and Dominica late Wednesday and then just south of Puerto Rico on Thursday. From there, the European model guidance forecasts that this system will miss Hispaniola and then track very close to the north coast of Jamaica on Sunday.
Beyond Sunday, the European model guidance forecasts a track that takes Isaac-to-be across western Cuba next Tuesday and then northward towards western Florida and the Florida Panhandle by next Thursday as possibly a hurricane.
So, all residents and vacationers in the Leeward Islands, Virgin Islands and Puerto Rico should prepare for tropical storm conditions. Those of you further west across Jamaica, the Cayman Islands and Cuba should closely monitor the progress of TD 9/Isaac. It is looking more and more likely that this system will be a hurricane when it tracks very close to Jamaica on Sunday.
Finally, all residents and vacationers across the Florida Peninsula and the Florida Panhandle need to keep very close tabs on the forecast track of this system. Go over your hurricane preparedness kits today and make sure you know what to do should Isaac come knocking on Florida’s door later next week.
I am monitoring Tropical Depression #9 very closely and will continue to update you on the latest.
For more on this story go to
http://www.crownweather.com/?page_id=4557
