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3:30 PM 10 September 2012 Update For some reason (I have no idea why), NHC decided to do a renumber and changed back to Invest 91L. Renumbers are uncommon, but not this year - I think that this makes the third time that they have backed off on an upgrade. At any rate, the system looks like it will soon be a TD so I'm going to let everything remain as is for now. Hurricane Michael is still moving west but should soon make an expected turn more to the north. ED 12:30 PM 10 September 2012 Update Just a short update to reflect a pending upgrade of Invest 91L to a Tropical Depression. Navy NRL and Best Track have already established the system as a TD and I suspect that NHC will follow suit shortly. Leslie remains a Tropical Storm as the cyclone heads for eastern Newfoundland. Latest NHC Watches/Warnings are as follows: A HURRICANE WATCH IS IN EFFECT FOR... * NEWFOUNDLAND FROM STONES COVE TO CHARLOTTETOWN A TROPICAL STORM WARNING IS EFFECT FOR... * NEWFOUNDLAND FROM INDIAN HARBOUR TO TRITON ED 8:30 AM 8 September 2012 Update Leslie, currently a tropical storm, is forecast to regain Hurricane Strength as it passes east of Bermuda. Folks in Canada and Newfoundland will want to watch this system, however. Leslie is also bringing large swells to the east coast. Michael continues out to sea. 90L in the Gulf never got going, and a new system in the far east atlantic, 91L, is being tracked, but this as well is likely to remain at sea. In the immediate future there is not much threatening US or Caribbean land areas, and it may be better to watch for systems close to home possibly a week or so from now. {{CHC}} 2:30 PM 5 September 2012 Update Leslie is now a hurricane south of Bermuda, and is expected to be in an increasingly favorable oceanic-atmospheric environment over the next few days for potentially significant intensification. Leslie is a large tropical cyclone with long lasting swells, high waves, and tropical storm force winds extending well away from the center. Interests in and around Bermuda may want to begin taking precautionary measures for the likely impacts from very inclement weather and waves, regardless of whether or not the cyclone makes a "direct hit" on the island. In addition, despite its distance from the U.S. mainland, Hurricane Leslie is expected to create a high risk of dangerous rip currents and shore breaks for many beaches along the U.S. east coast throughout much of this week. In the northern Gulf of Mexico, the area of low pressure located just about on or offshore of the western Florida panhandle and drifting south or south-southwest (Invest 90L) has become a little better organized today, and some tropical depression-like weather is already occurring from southeastern Louisiana to the panhandle, and then into the northern Gulf. NHC gives this disturbance a 40% chance of becoming a numbered tropical depression within the next 48 hours. Ciel 7:30 AM 5 September 2012 Update The disturbance in the northern Gulf is now being tracked as 90L, the slow movement of this disturbance does give it time to develop over the next few days, but the primary threat will be more rain, and some surge along the coast. Gulf Satellite Recording ( Alternate Link ) {{NorthGulfRadar}} {{NortheastGulfRadar}} Bermuda Weather Service 3:30 AM 5 September Update Things remain active with two named tropical cyclones in the central Atlantic, plus one unnamed disturbance worth watching in the northern Gulf of Mexico. Ciel ![]() 8:30PM 4 September Update Tropical Storm Michael has formed in the Central Atlantic, moving northward and should remain no threat to land. An area over southern Alabama, which only has a minor bit of energy from Isaac, may drift into the northern Gulf of Mexico later in the week, this system could enhance rainfall along the Big Bend and parts of Florida and Southern Georgia. It will be worth watching late this week into the weekend. Original Update Post tropical cyclone Kirk has moved rapidly off to the northeast and merged with a front in the far north Atlantic. Invest 99L in the central Atlantic is moving to the west southwest. Its a small low level system that fires intermittent bursts of convection to the east of the center. Chances for additional development are currently rather low. The system should turn more to the northwest in a couple of days. The center of Tropical Storm Leslie has often been exposed today with convection displaced to the southeast of the center by strong northwesterly windshear. Leslie is located about 400 miles to the north of the Leeward Islands with winds of 50 knots and the storm is expected to drift slowly north through midweek. Windshear might weaken the cyclone a bit on Monday but with some relaxation of the shear by midweek an increase in intensity and storm size is possible IF the system can survive the shear on Monday. Although eventual movement and intensity for the latter part of the workweek are uncertain with this sheared system, folks in Bermuda should continue to monitor Leslie. Another disorganized wave has left the west African coast. ED {{StormLinks|Michael|13|13|2012|13|Michael}} {{StormLinks|Leslie|12|12|2012|12|TS Leslie}} {{StormLinks|TD14|14|14|2012|14|TD 14}} |
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Ed, First, I have been a regular, avid user of the site since 2004. Easily, the best site for obtaining information and insight regarding tropical systems. Next, on the subject of Leslie, I was wondering what your prognostication was for the future track of the storm. Yes, I know that it may be too early to ask this -- but as someone who also resides in Nova Scotia -- and am familiar with the effects of the last hit by a tropical system (I believe, back in 2007) -- I was wondering where you saw this system -- both for potential strength and course. Thanks. Sharpe |
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Well yes, it is a bit early - but later in the week check out the Forecast Lounge for discussions on the long range outlook for Leslie. Currently, windshear has exposed the low level center with all of the convection displaced to the east through southeast. A slow movement to the west is obvious and the center has already reached the 48-hour forecast longitude issued earlier this morning. As long as the center is exposed, the movement is going to align more with the lower level flow. ED |
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Extraordinary -- two post-tropical storms impacting Canada's Atlantic provinces as hurricanes and at approximately the same time. Certainly, Leslie poses the most immediate threat to Newfoundland and to Nova Scotia. The most surprising aspect of that storm is its strengthening as it continues north in the Atlantic. Conventional wisdom would dictate that the water temperatures would cool as it traveled northward. It is apparent, from the prediction models, that the opposite is occurring with Leslie -- strengthening to a Category 2. Sharpe |
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Any insight as to how Leslie will re-strengthen to hurricane status even though it continues it's drag into the North Atlantic? |
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As noted in the 10/03Z NHC Discussion bulletin "LESLIE CONTINUES TO LACK ANY INNER-CORE DEEP CONVECTION AND ALSO HAS A BROAD INNER-CORE WIND FIELD...WHICH SHOULD INHIBIT ANY SIGNIFICANT STRENGTHENING IN THE SHORT TERM. HOWEVER...AS THE CYCLONE BEGINS TO ACCELERATE RAPIDLY NORTHEASTWARD...THE ADDITIONAL FORWARD SPEED COMPONENT SHOULD INCREASE THE WIND SPEEDS IN THE EASTERN SEMICIRCLE. SINCE LESLIE IS FORECAST TO BE MOVING AT NEARLY 35 KT BY 36 HOURS...THIS COULD ALLOW THE CYCLONE TO ACHIEVE HURRICANE STATUS AGAIN BEFORE THE CYCLONE AFFECTS SOUTHEASTERN NEWFOUNDLAND." However, it should also be noted that NHC has been lowering the forecasted wind speeds in the 24-48 hour timeframe for about the past 24 hours, i.e., the expectation for regaining hurricane intensity has been on the decline. Its usually difficult for a large tropical cyclone to redevelop its central core while moving forward at a rapidly increasing speed. ED |