Warmer than normal water temps likely to fuel Leslie as rest of tropics stay very busy

Atlantic Sea Surface Temperature Anomalies

Atlantic Sea Surface Temperature Anomalies

Sea surface temps are running at least one degree Celsius above normal across much of the northwest Atlantic. In fact, there are large areas of plus two and three Celsius just off the Canadian Maritimes. This translates in to added heat content and Leslie is poised to take advantage of it over the next week or more.

The current NHC forecast track has Leslie moving very slowly over the next few days as steering currents remain weak. The track takes the center just to the west of Bermuda but since Leslie is a large storm with a huge wind field, the effects will be felt on the island in the way of large, battering waves, heavy rain and high winds. I suspect it won’t be too much longer until we see a hurricane watch posted for the island.

With all of this warmer than normal water around, Leslie looks like it could strengthen in to quite a strong hurricane in the models. Add to this what appears to be a very favorable upper level outflow pattern and it is possible that Leslie becomes the first category three hurricane of the season. We have been in this pattern of seeing storms/hurricanes intensify out of the deep tropics and I don’t see any reason to believe that Leslie will be any different.

In the longer range, the Euro continues its westward forecast for Leslie, taking it very close to Nova Scotia and Newfoundland. Any further west and we could be looking at a possible brush with portions of New England as well. Much of this will have to do with the way a trough is supposed to develop in the Tennessee Valley this weekend and beyond. If it is weaker or digs in farther west, even by a little, then the high pressure area over the western Atlantic can build in more and push Leslie a degree or two of longitude west. I will be watching closely to see if this trough acts to capture Leslie and swing it north-northwest or whether the trough acts to push Leslie out to the north-northeast. How this plays out will determine what, if any, landmass is directly impacted.

One effect that I have made mention of for several days now is the increasing swells that will roll in to the East Coast. The NHC continues to make mention of this in their discussions and I want to emphasize the importance of understanding how dangerous rough surf can be- even with a storm/hurricane hundreds of miles off the coast. Check out this video that I produced last year as part of a preparedness campaign with Olympus Insurance out of Florida:

Elsewhere, we now have tropical storm Michael which will be officially named at 11am ET on the NHC advisory. The small storm will be short-lived and not affect land but it will bring the total number of named storms to 13 this season. While Michael is much smaller than Leslie, it is clearly a tropical storm and is of interest to shipping lanes in the open Atlantic.

The east Pacific is calming down and I do not see any new areas of concern developing anytime soon.

I will be working on the daily video blog for our iPhone app and will have it uploaded in just a little while. We are also eagerly anticipating the first major update to the app any day now. The update will greatly enhance the app and allow for manual refresh of the video blogs. As soon as it is approved by Apple, I will add a separate blog post. Speaking of blogs, I’ll update this blog later this afternoon.

 

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Latest Euro model to raise a few eyebrows along East Coast

Euro Forecast for Leslie Shows it Getting Closer to the East Coast of U.S.

Euro Forecast for Leslie Shows it Getting Closer to the East Coast of U.S.

It looks like the weak nature of Leslie has allowed it to track a little more west than originally forecast and this may be enough to trap it under a building ridge of high pressure over the western Atlantic in the coming days.

The latest ECMWF model shows quite a significant westward shift in the track of Leslie beyond day five. In fact, the model now shows a landfall in Nova Scotia at day nine, which is a change from the curving-out-to-sea scenario that has been the norm as of late for that model.

Both the GFS and the Euro also indicate that Leslie will grow to be a powerful hurricane with nearly ideal upper level conditions over water temps that are running several degrees above normal in some places. This will lead to a substantial wave event along the East Coast and of course, Bermuda, later this week and in to the weekend. This, in and of itself, could be a big problem with days and days of pounding surf. I’ll address this more on tomorrow’s blog post.

For now, Leslie is rather disorganized and moving generally northward. We’ll see what the NHC has to say on their next forecast package. I suspect we’ll start to see some subtle shifts to the west in the track and an increase in the intensity over time.

I’ll post more here late tonight and then again tomorrow morning. For a video discussion of the tropics, be sure to pick up our iPhone app in the App Store. We have a new update coming out any day now which will greatly improve functionality and I’ll post a separate write-up about that once Apple has approved it.

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Leslie not going anywhere fast it seems, Bermuda should monitor closely

Leslie Could Track Close to Bermuda Late Next Week

Leslie Could Track Close to Bermuda Late Next Week

TS Leslie remains just below hurricane intensity as a fairly constant northerly shear pattern is in place, keeping the deep convection from wrapping around the low level center. It is quite remarkable how hostile the deep tropics have been again this season which in turn has meant that we’ve had no major hurricanes as of yet (no category three or higher hurricanes). However, the global models all show Leslie moving in to a more favorable environment over the next several days and it should become a fairly strong hurricane at that time. Ocean temps are warm and the wind shear is forecast to relax considerably.

The steering pattern is complex and could have some big implications for Bermuda as the coming week unfolds. Right now, the storm is moving along to the northwest at a fairly good pace, 15 mph. This will soon change as the flow in the atmosphere changes and Leslie gets stuck in the middle of this pattern change. There is a chance it could just meander out in the Atlantic for a couple of days. How close this happens to Bermuda remains to be seen but there is a chance that Leslie could impact the island beyond the NHC five day forecast period. Interests in Bermuda should just keep an eye on the future predictions for Leslie this coming week.

Surfers should also keep an eye as well since the farther west Leslie tracks and the stronger it gets, the more long period swell action the East Coast will see. We’ll know more about what to expect later this week but it looks like there will be some increase in the surf along parts of the East Coast by next weekend.

The remainder of the Atlantic is quiet in terms of any other issues to be concerned about. I think we are heading for a lull in the action once Leslie moves out but that could take a while as mentioned above.

I will have more here tomorrow morning.

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