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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Tropical depression 9 forms, forecast to become strong hurricane in the Caribbean Sea

Tropical Depression Nine

Tropical Depression Nine

Well it took a bit of time but the tropical wave that we have been watching for the last several days has strengthened to TD #9. It is currently situated well east of the Leeward Islands but will close in rather quickly, bringing tropical storm conditions to the region within 36 hours.

The depression is currently winning the battle against the unusually dry air that has been in place all hurricane season across the deep tropics. Now that it is moving across ocean heat content that is considerably higher than in recent days, the amount of energy needed to fuel the deep convection is in place. Keep in mind that sea surface temperatures and heat content only increase ahead of the soon-to-be storm (which will be Isaac).

Interests in the Leewards need to be ready for a strengthening tropical storm and a large one at that. This means squally weather, heavy rains and winds gusting to near hurricane force in less than 48 hours.

Once past the Lesser Antilles, what would presumably be Isaac is forecast by the NHC to pass south of Puerto Rico and just clip portions of Hispaniola as it heads to a position just south of Cuba in five days. Now this part is extremely important. If the cyclone remains far enough south of these land masses, it could strengthen quite a bit. On the other hand, if the delicate circulation gets tangled up within the mountains of the Greater Antilles, it would almost certainly result in a weaker, disrupted storm/hurricane. The next few days will be critical in terms of what happens next.

I know it is natural to want to know what happens after the five day forecast period. There are certainly plenty of sites that have long range models available. Let’s just say that interests in Florida and indeed the Southeast U.S. as a whole need to watch the progress of this developing system very closely. There are some indications in the long range guidance that it could end up in the eastern Gulf of Mexico while other models suggest a path east of Florida. So there is the problem. It’s just too far out to even worry about right now. My best advice is to monitor and be ready to act. You should already have a hurricane plan in place for just such an event. If not, you better be ready, if not for this one, then for the rest of the season ahead.

We will have a lot more information in the coming days as recon planes from NOAA and the Air Force will be checking the system out thoroughly. This information will help to make the forecasts even better and will give us all the detail we need to prepare accordingly.

I would also like to remind our readers that we do have an app in the App Store that is available for purchase. It is a great way to keep up with the latest from HurricaneTrack.com on your iPhone, iPod Touch or even iPad. The app features this blog, our Twitter posts, Facebook updates, live weather data during landfall missions (might we have one coming up soon?), live web cam images from our own instrumented wind towers, video blogs EXCLUSIVE to our app and even a GPS tracking map to show our location while we are out in the field! To get it now click here. If what is a shoe-in to become Isaac makes landfall in the U.S., our app will literally take you there like nothing you have ever seen in a mobile app! It’s a great way to support our work while getting something innovative and informative in return.

I’ll post another update here later this afternoon. Keep in mind that our private clients who have not logged in this season that we do have our LIVE video briefing at 2pm ET on the Client Services site.

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Gordon now a hurricane, Helene just about on the coast and 94L looks like it could be an issue

Satellite Shot of an Increasingly Busy Tropics

Satellite Shot of an Increasingly Busy Tropics

There is a lot to go over at this early morning hour that I am posting this blog update. The tropics have indeed become quite active and we are probably only just getting started. Notice in the satellite photo the marked increase in convection across the Atlantic Basin. This is part due to a slightly more favorable upward motion pattern or MJO pulse that is currently passing through the Basin. Just a few days ago, there was hardly a cloud to be found much less any deep thunderstorm activity. I think this is a sign that things are changing and the tropics are about to get busy.

First, Gordon. It is now a hurricane, the 2nd one of the Atlantic season. It could bring tropical storm conditions to portions of the Azores Islands over the next few days but should weaken over progressively cooler waters. This will keep the overall effects to a minimum. Still, it’s rare to have a tropical storm pass through the Azores, it does happen, but it’s not often.

Next we have TS Helene just hugging the coast of eastern Mexico as a minimal tropical storm. It should move inland within a few hours and slowly dissipate. However, the threat of localized heavy rain will persist in the region for the next several days. It is also possible that Helene will emerge back out over the western Gulf early next week. We’ll have to keep an eye on that since if that happens, the pattern would be such that it could turn to the northeast and bring unsettled weather to portions of the U.S. Gulf Coast by mid-week.

Then there is invest area 94L out near the Cape Verde Islands. This system certainly has the look of becoming quite a potent tropical cyclone over the next three to five days. The GFS model is seemingly the most aggressive with development while the latest run of the ECMWF or Euro model indicates quite a weak system moving across the Atlantic and through the northern Caribbean. While I suppose this scenario has to be considered since the norm this season has been for lack-luster performance in the deep tropics, I think we are in enough of a favorable pattern to see some significant development from 94L.

The future track of what ever 94L becomes will depend a lot on how strong it gets and how soon. It does look as though a fairly substantial subtropical ridge will be in place over a good deal of the Atlantic for the next several days at least. This should keep the system on a general westward track and it could pose a threat to the Lesser Antilles in about five days or so. Obviously, if it does not develop much as the Euro shows as of late, then it won’t matter much in terms of impact to the islands. However, the GFS model depicts quite a strong cyclone moving through the eastern Caribbean. Considering the time of year we are in and the potential, I think it’s fair to say that folks in the Windwards and Leewards need to pay close attention to 94L in the coming days.

Other than that, there are no imminent threats for our coastal areas this weekend. I’ll post another update here later in the afternoon with the video blog coming around that time as well for our HurricaneTrack app. As I mentioned yesterday, if you have an iOS device, then you will want to add our app to your collection. It is a great way to keep up to date on the go but will also serve as an outstanding source of information, live weather data, web cam images and numerous video posts during any field missions that we have. Plus, we are about to push an update that will include our own set of tracking maps to round out a great start to our entry in to the app market. Search “hurricanetrack” (all one word) in the App Store and get it connected on your iPhone, iPod Touch or iPad.

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New depression forming in the SW Gulf while 94L develops in east Atlantic

Remnants of TD 7 in the SW Gulf

Remnants of TD 7 in the SW Gulf

Early morning satellite imagery shows that what was once TD 7 is coming back to life again in the southwest Gulf of Mexico. The NHC is indicating a 70% chance of it becoming a tropical depression again before it moves inland this weekend.

Computer models suggest a WNW to NE track towards Mexico as a tropical storm or category one hurricane (SHIPs model shows it reaching hurricane intensity). The overall circulation is fairly small and will only affect a limited area of the southwest to western Gulf and I do not see much impact for Texas. However, it is possible that some of the northern rain bands will move in to south Texas over the weekend. The main threat will be very heavy rains for Mexico with the possibility of a strengthening tropical storm at landfall. The NHC has tasked a recon plane to investigate the area later today if conditions warrant.

Meanwhile, we have a new area of interest just off the African coast that certainly bears watching. It has been designated as invest 94L and should steadily develop as it moves westward over the deep tropics.

All of the global computer models indicate that it will develop and it is likely to become a hurricane at some point since conditions are becoming more favorable along its path. This will be one to watch very closely as we move through the week next week. For now, it is in its early stages of development and we’ll just monitor how it develops over the weekend.

In the east Pacific, Hector has dissipated and there are no other areas of concern brewing in that region. I’ll post another blog here later this afternoon or early evening and will cover all of the goings on in the tropics thoroughly in the video blog to be posted in our app early this afternoon.

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TS Gordon forecast to become hurricane while we also watch southwest Gulf

Heat Content Track Map Showing TS Gordon

Heat Content Track Map Showing TS Gordon

The NHC is issuing advisories on TS Gordon now which originated as a strong tropical wave several days ago after emerging from the coast of Africa. Gordon is forecast to become a hurricane as it moves off to the east-northeast over the sub-tropical Atlantic. I mention “subtropical” because Gordon formed well outside of the usual “MDR” region between Africa and the Lesser Antilles, south of about 20 N latitude. Conditions in that corridor have been quite unkind to development over the last few weeks and this was the case when the tropical wave that became Gordon traversed the region in recent days.

Now that environmental conditions have improved, we have a tropical storm to track. Note that the ocean heat content is not high at all along Gordon’s path but there’s just enough energy to push the storm to hurricane intensity over the next few days. The forecast track takes Gordon just to the south of the Azores Islands as it moves back towards the eastern Atlantic and eventually, cooler waters.

The next area to monitor will be the southwest Gulf of Mexico as energy from what was once TD 7 moves in to the very warm water and a more favorable environment for development. Several of the global computer models are indicating that a weak area of low pressure will eventually form somewhere in the southwest Gulf within the next five to seven days. I do not see any indications just yet of a strong system which is good news considering that water temps in the western Gulf are quite warm. I think that at the very least, interests in the region can expect an increase in squally weather as the low takes shape though it should be a fairly slow process.

Elsewhere, it seems that the models are also hinting at a potential Cape Verde storm developing over the next week or so from a tropical wave that will move off of Africa. Both the GFS and the ECMWF show this and have been a little more consistent with this scenario over the last few runs. We’ll see – I am not convinced just because of how negative the conditions have been up through the present time. I also know that things can change and we may have an active period coming up that includes a long-track storm originating from Africa. Time will tell…

I wanted to mention too that in today’s video blog that will be posted to the HurricaneTrack app, I will take a look back at hurricane Andrew from 1992. We are coming up on the 20 year anniversary of that category five hurricane and as one of our private clients suggested, it would be good to compare how things were then in terms of information, evacuation orders, etc. and what might happen if an Andrew type hurricane were to happen again today. That, and a detailed look at the tropics, will be part of today’s video blog so check it out later this afternoon. Remember that, unfortunately for now, you have to completely close the app and restart it to get the video blogs to refresh. We will have a nice pull-down refresh coming in the next update which is coming soon!

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