Eskimo Joe Posted August 30, 2012 Share Posted August 30, 2012 Tropical Depression #12 has formed in the Atlantic Basin. Discussion, images, observations and thoughts are welcome! From the National Hurricane Center: SATELLITE IMAGES INDICATE THAT THE AREA OF THE LOW PRESSURE OVER THECENTRAL TROPICAL ATLANTIC HAS DEVELOPED ENOUGH ORGANIZATION TO BE CONSIDERED A TROPICAL DEPRESSION. A WELL-DEFINED CURVED BAND IS ON THE WESTERN SIDE OF THE CIRCULATION...AND THE CENTER APPEARS TO BE EMBEDDED ON THE EASTERN SIDE OF THE BAND. THE ADVISORY INTENSITY IS 30 KT...WHICH IS BASED ON A BLEND OF TAFB AND SAB 1200 UTC ESTIMATES... THOUGH IT MIGHT BE A LITTLE STRONGER BASED ON THE LATEST PICTURES. AS THE DEPRESSION MOVES OVER WARM WATERS DURING THE NEXT FEW DAYS...FURTHER STRENGTHENING SEEMS LIKELY WHILE AN UPPER-LEVEL ANTICYCLONE BUILDS NEAR THE SYSTEM. THE LONG RANGE INTENSITY SEEMS RATHER UNCERTAIN AS THE GLOBAL MODELS SHOW WILDLY DIFFERENT SYNOPTIC PATTERNS. THE NHC WIND SPEED FORECAST IS CLOSE TO THE INTENSITY CONSENSUS...AND COULD BE CONSERVATIVE IF THE LOW SHEAR ENVIRONMENT SHOWN BY THE GFS MATERIALIZES. THE INITIAL MOTION IS ABOUT 275/17. MODEL GUIDANCE SUGGESTS THE DEPRESSION WILL TURN TOWARD THE WEST-NORTHWEST SOON AS IT MOVES TOWARD A WEAKNESS IN THE SUBTROPICAL RIDGE...PARTIALLY RELATED TO KIRK. WHILE THE RIDGE IS EXPECTED TO REBUILD SOMEWHAT AS KIRK MOVES OUT TO SEA...ALL OF THE GLOBAL MODELS SHOW TROUGHING BETWEEN 60W-70W IN THE MEDIUM RANGE PERIOD...WHICH WILL PROBABLY TURN THE CYCLONE TO THE NORTHWEST AND NORTH. THERE IS A LOT OF UNCERTAINTY IN THE LONG RANGE RELATED TO WHETHER THE SYSTEM RECURVES AHEAD OF THE TROUGH OR GETS TRAPPED BENEATH A REBUILDING RIDGE. THE NHC FORECAST IS A BIT FASTER AND WEST OF THE CONSENSUS THROUGHOUT THE PERIOD...BUT THIS FORECAST STILL KEEPS THE CYCLONE WELL TO THE NORTHEAST OF THE LESSER ANTILLES. First Advisory text: ...YET ANOTHER DEPRESSION FORMS IN THE TROPICAL ATLANTIC OCEAN...SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...14.1N 43.4W ABOUT 1185 MI...1905 KM E OF THE WINDWARD ISLANDS MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 20 MPH...32 KM/H MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES WATCHES AND WARNINGS -------------------- THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 1100 AM EDT...1500 UTC...THE CENTER OF TROPICAL DEPRESSION TWELVE WAS LOCATED NEAR LATITUDE 14.1 NORTH...LONGITUDE 43.4 WEST. THE DEPRESSION IS MOVING TOWARD THE WEST NEAR 20 MPH...32 KM/H. A MOTION TOWARD THE WEST-NORTHWEST AT A SLOWER FORWARD SPEED IS EXPECTED DURING THE NEXT COUPLE OF DAYS. MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/H...WITH HIGHER GUSTS. THE DEPRESSION IS EXPECTED TO BECOME A TROPICAL STORM LATER TODAY...AND COULD BECOME A HURRICANE OVER THE WEEKEND. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB...29.74 INCHES. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 30, 2012 Author Share Posted August 30, 2012 The official forecast track looks to take it east of Bermuda...looks fishy at first glance. Link to comment Share on other sites More sharing options...
icebreaker5221 Posted August 30, 2012 Share Posted August 30, 2012 Models have had a right bias all season. I wouldn't be surprised to see TD12 come much closer to Bermuda than initially advertised. No real threat to the U.S. either way. Link to comment Share on other sites More sharing options...
PSUBlizzicane2007 Posted August 30, 2012 Share Posted August 30, 2012 This will be an interesting one to watch. Right now, I'd say Bermuda is the only land mass that really needs to watch it, but the most recent model solutions are interesting. The 00Z Euro really wants to amplify the Bermuda High to the point that 12L shifts west in/around Bermuda, then speeds northwards towards Maine/NB/NS. The 06Z GFS wants to amplify the high also...but with a further east centre so that 12L ends up racing across eastern Newfoundland. Certainly Isaac's remnants will play a role in strengthening the trough that will eventually curve 12L to the north. Just how much is a question, especially with respect to that high. Link to comment Share on other sites More sharing options...
Jmister Posted August 30, 2012 Share Posted August 30, 2012 We have Leslie! Kind of a surprise update... TROPICAL STORM LESLIE TROPICAL CYCLONE UPDATE NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 200 PM EDT THU AUG 30 2012 ...TROPICAL STORM LESLIE FORMS... DATA FROM NOAA BUOY 41041 AND SATELLITE IMAGES SHOW THAT TROPICAL DEPRESSION TWELVE HAS BECOME A TROPICAL STORM. MAXIMUM SUSTAINED WINDS ARE NOW 40 MPH...65 KM/H...WITH HIGHER GUSTS. NO CHANGE TO THE TRACK OR INTENSITY FORECAST IS REQUIRED AT THIS TIME. THIS IS THE SECOND-EARLIEST FORMATION OF THE 12TH NAMED STORM ON RECORD IN THE ATLANTIC BASIN...ECLIPSED ONLY BY LUIS OF 1995. SUMMARY OF 0200 PM...1800 UTC...INFORMATION -------------------------------------------------- LOCATION...14.3N 44.3W ABOUT 1125 MI...1810 KM E OF THE WINDWARD ISLANDS MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 20 MPH...32 KM/H MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES Link to comment Share on other sites More sharing options...
neweathereye Posted August 30, 2012 Share Posted August 30, 2012 TD12 is now Tropical Storm Leslie just an FYI folks....threat to EC or not?? Craig http://northeastweathereye.com Augusta Maine 000 WTNT62 KNHC 301730 TCUAT2 TROPICAL STORM LESLIE TROPICAL CYCLONE UPDATE NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 200 PM EDT THU AUG 30 2012 ...TROPICAL STORM LESLIE FORMS... DATA FROM NOAA BUOY 41041 AND SATELLITE IMAGES SHOW THAT TROPICAL DEPRESSION TWELVE HAS BECOME A TROPICAL STORM. MAXIMUM SUSTAINED WINDS ARE NOW 40 MPH...65 KM/H...WITH HIGHER GUSTS. NO CHANGE TO THE TRACK OR INTENSITY FORECAST IS REQUIRED AT THIS TIME. THIS IS THE SECOND-EARLIEST FORMATION OF THE 12TH NAMED STORM ON RECORD IN THE ATLANTIC BASIN...ECLIPSED ONLY BY LUIS OF 1995. SUMMARY OF 0200 PM...1800 UTC...INFORMATION -------------------------------------------------- LOCATION...14.3N 44.3W ABOUT 1125 MI...1810 KM E OF THE WINDWARD ISLANDS MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 20 MPH...32 KM/H MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES $$ FORECASTER BLAKE Link to comment Share on other sites More sharing options...
Ed Lizard Posted August 30, 2012 Share Posted August 30, 2012 TD12 is now Tropical Storm Leslie just an FYI folks....threat to EC or not?? Craig http://northeastweathereye.com Augusta Maine A few days ago GFS held out hope, but latest runs have been fishy. No 1004 mb or below GFS spaghetti goes near ECUSA. Canadian says fish. Last night's Euro was glass half full optimistic. Waiting on new Euro, but gut feeling it loses that loving feeling. Link to comment Share on other sites More sharing options...
NorEaster27 Posted August 30, 2012 Share Posted August 30, 2012 clear fish to me, outside chance of a bermuda threat....we have a strong trough moving off the coast early next week. Cant see how that doesnt shunt this storm way east. Link to comment Share on other sites More sharing options...
Witness Protection Program Posted August 30, 2012 Share Posted August 30, 2012 Leslie may be a naked gun aimed at the east coast? Link to comment Share on other sites More sharing options...
atownwxwatcher Posted August 30, 2012 Share Posted August 30, 2012 12 Z ECM still keeps Cape Cod region in potential play... Link to comment Share on other sites More sharing options...
billgwx Posted August 30, 2012 Share Posted August 30, 2012 The anticyclone to the north of and traveling in tandem with Leslie might give it a little more westward push before any recurvature. IMO it's worth watching along the East Coast. Does anyone remember how the ECMWF modeled Irene in the 5-10 day range, before she became an obvious EC threat? That may offer clues as to future Leslie model trends. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 30, 2012 Author Share Posted August 30, 2012 Permit me to observations: I have noticed this year that tropical storms in the Atlantic Basin have not strengthened as quickly as initially progged by numerical guidance. The storm tracks appears to wind up to the west of the initial track guidance (ie: Isaac) While I am not implying Leslie will ultimately make a landfall on the EC, I am merely making a casual observation that coastal communities, especially in NE would be wise to keep an eye on this one. Link to comment Share on other sites More sharing options...
turtlehurricane Posted August 30, 2012 Share Posted August 30, 2012 Based on the GFS I'd say Leslie has potential to track more west than currently projected. If the subtropical ridge is stronger than expected it could end up going due west towards the Bahamas/Florida, if that high pressure after the recurve is stronger than expected it could end up going towards the Northeast. Just too early in the game to write this one off. Link to comment Share on other sites More sharing options...
NorEaster27 Posted August 30, 2012 Share Posted August 30, 2012 The anticyclone to the north of and traveling in tandem with Leslie might give it a little more westward push before any recurvature. IMO it's worth watching along the East Coast. Does anyone remember how the ECMWF modeled Irene in the 5-10 day range, before she became an obvious EC threat? That may offer clues as to future Leslie model trends. a few runs of the Euro sent her into the gulf toward NO, with such a strong trough forecasted to swing off the coast early next week, its very hard to see how this become any sort of threat for the east coast. Especially given the quick strengthening of the storm today. This should follow the trough left by Kirk. Link to comment Share on other sites More sharing options...
Max Posted August 30, 2012 Share Posted August 30, 2012 Kirk is way too small to create a big enough trough for Leslie to follow through. Also there seems to be a anticyclone in between Kirk and Leslie that is moving Leslie west at a good clip. It seems that right now the faster Leslie moves through the central Atlantic the better chances it has at threatening the EC down the road. Right now I'm on the Euro train and favor a more westerly track early on. Link to comment Share on other sites More sharing options...
GaWx Posted August 30, 2012 Share Posted August 30, 2012 Based on the GFS I'd say Leslie has potential to track more west than currently projected. If the subtropical ridge is stronger than expected it could end up going due west towards the Bahamas/Florida, if that high pressure after the recurve is stronger than expected it could end up going towards the Northeast. Just too early in the game to write this one off. It is too early to write off this one. However, based on the near unanimous agreement for a sharp recurve near 60W by all of the 12Z major models, including their ensemble means, as well as climo for a well developed storm that far east, the chances for a SE US hit are extremely low..I'd say less than 5% with most of that very small chance being NC. Link to comment Share on other sites More sharing options...
phil882 Posted August 30, 2012 Share Posted August 30, 2012 The ECWMF seems to keep the storm much weaker than what is currently expected in the near term and early mid-range. Thus when it reaches 25-30N the 500 hPa trough is not quite strong enough to pick it up, since the 500 hPa low associated with Leslie is not as intense as projected on the GFS. This eventually allows for Leslie to hesitate long enough for a ridge to build back in and have Leslie continue a westward motion. Overall I think the GFS has a better handle on the intensity of Leslie in the short term, which will strongly dictate if the storm recurves earlier into the open Atlantic. Thus, I lean towards the GFS solution. Link to comment Share on other sites More sharing options...
hm8 Posted August 30, 2012 Share Posted August 30, 2012 NHC pretty bullish on intensity this far out Link to comment Share on other sites More sharing options...
Max Posted August 30, 2012 Share Posted August 30, 2012 Leslie about to pass really close to NOAA Buoy 41041. http://www.ndbc.noaa.gov/station_page.php?station=41041 Link to comment Share on other sites More sharing options...
GaWx Posted August 30, 2012 Share Posted August 30, 2012 Does anyone remember how the ECMWF modeled Irene in the 5-10 day range, before she became an obvious EC threat? That may offer clues as to future Leslie model trends. I don't have to remember the Irene model runs. I'm crazy enough to still have my notes on Irene for both the GFS and the Euro (actual U.S. hit period was 8/27-8): 1) Euro runs had hits on the U.S. on all runs starting with the 8/19 0Z run although they would have almost definitely shown hits on all runs starting 8/17 0Z had they gone longer than 10 days. Euro runs: - 8/17-8: back and forth SE coast to central Gulf - 8/19-20: S FL - 8/21: GA/SC - 8/22-7: NC/up east coast 2) The GFS, impressively enough, had hits on the U.S. on every run starting with the 6Z 8/15 run..some 50 runs or so in a row. GFS runs: - 8/15-8: mostly FL - 8/19: Gulf - 8/20- early 8/21: S FL - 8/21 late- 8/22 early: GA, SC - 8/22: NC/up east coast - 8/23-4: Long Island/New England - 8/25-7: NC/up east coast The Euro did somewhat better as it seemed to be ahead of the GFS by ~24 hours 8/19-22 runs and never had the first hit on the NE US as did the GFS 8/23-4. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted August 30, 2012 Share Posted August 30, 2012 18 Z GFS has just come substantially closer to the 12 Z ECM with leslie.. Link to comment Share on other sites More sharing options...
Max Posted August 31, 2012 Share Posted August 31, 2012 Looks like Buoy 41041 might take a direct hit if the center is under that deep convection. Pressure is already down to 1004mb at that buoy. Link to comment Share on other sites More sharing options...
dan88 Posted August 31, 2012 Share Posted August 31, 2012 Looks like Buoy 41041 might take a direct hit if the center is under that deep convection. Pressure is already down to 1004mb at that buoy. Winds have shifted to the WSW there now and pressure is on the rise so it has recently passed to the North of the buoy. Min pressure was 1004.1mb. Link to comment Share on other sites More sharing options...
phil882 Posted August 31, 2012 Share Posted August 31, 2012 Looks like a little bit of northeasterly shear over the system tonight... convective presentation is a bit ragged as well. Link to comment Share on other sites More sharing options...
Snow_Miser Posted August 31, 2012 Share Posted August 31, 2012 Just like Ernesto, the forward speed of this system may also hurt it in the end, as the system may be moving too quickly for the circulations to vertically stack and for this thing to really intensify in the near-term. Link to comment Share on other sites More sharing options...
andyhb Posted August 31, 2012 Share Posted August 31, 2012 Just like Ernesto, the forward speed of this system may also hurt it in the end, as the system may be moving too quickly for the circulations to vertically stack and for this thing to really intensify in the near-term. Those looking for a potential US threat should probably find this to be a positive. Link to comment Share on other sites More sharing options...
atownwxwatcher Posted August 31, 2012 Share Posted August 31, 2012 FWIW the GFS tonight looks similar to the 12 Z ECM... Link to comment Share on other sites More sharing options...
free_man Posted August 31, 2012 Share Posted August 31, 2012 The anticyclone to the north of and traveling in tandem with Leslie might give it a little more westward push before any recurvature. IMO it's worth watching along the East Coast. Does anyone remember how the ECMWF modeled Irene in the 5-10 day range, before she became an obvious EC threat? That may offer clues as to future Leslie model trends. Couldn't agree more. Link to comment Share on other sites More sharing options...
phil882 Posted August 31, 2012 Share Posted August 31, 2012 Just like Ernesto, the forward speed of this system may also hurt it in the end, as the system may be moving too quickly for the circulations to vertically stack and for this thing to really intensify in the near-term. Those looking for a potential US threat should probably find this to be a positive. Not at all... the forward speed of this system will be far slower than both Ernesto and Helene. If anything, the system will have to battle easterly shear in the near term as the mid-level flow is more easterly than the low-level flow. Link to comment Share on other sites More sharing options...
Riptide Posted August 31, 2012 Share Posted August 31, 2012 0z GEFS Spaghetti plots are more enthusiastic about a potential landfall threat. Link to comment Share on other sites More sharing options...
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