Monthly Archives: August 2010

Hurricane Earl & Tropical Storm Diona

Hurricane Earl has been in an environment for continuing intensification and has blown up today and is now a Category 4 storm. There will probably be times where there will be an ERC (Eyewall Replacement Cycle) which is normal with a storm this strong. The intensification will be short term, probably 36-48 hours.

What was Invest 97L has been upgraded to Tropical Storm Fiona. Diona lack organization and the wind field is very large. The overall structure of Fiona is very poor and intensification will be slow. Most models are forecasting that Fiona may be a hurricane in 36-48 hours although the GFS model wants to dissipate Fiona is 2 or 3 days. The Models are still forecasting that Fiona will turn NW then N but there is a chance that the subtropical ridge will build back in and that will keep Diona from recurving. This is something forecasters will have to keep an eye on.


Tropics Are Hot

As Hurricane Danielle begins to lose strength and in a few days there will be the transition from tropical to extratropical.
In the meantime, there is Hurricane Earl which will be in a very favorable upper level environment as the shear will be extremely low and the SST’s will be very hot. The forecast is for Earl to become the second major hurricane in 36-72 hours. Although there is some slight differences in the models, they all have Earl making a NW turn and then N. I feel the model track will probably have to be adjusted left of the forecast now, and this brings Earl much closer to the southeast coast of the U.S. This may possibly have the clean side of Earl affecting those from N. Carolina upward to Long Island.

Invest 97L has had a lot of shear but has an excellent cyclonic turning but very little convection. I do not think the models have a grasp on Invest 97L being that it is not even be classified as a depression yet. The models at the moment are forecasting that Invest 97L will turn NW and then N because of a weakness in the ridge. Although a stronger Hurricane Earl would help keep the ridge open a little longer, I don’t see this happening. 97L has been on a westward track and probably will stay that way longer than the forecast then there will be a NW turn. The European model is forecasting that Invest 97l will be a hurricane with landfall somewhere in the central Florida coast but this model has had some problems this year. I believe once 97L has gotten to around 50° W longitude – we will have a better idea where 97L will be headed.

Now after all that, there is a new disturbance that has just come off the coast of Africa. This one at the time shows no development but this is the time of year for all these waves to possibly develop quickly.


Tropical Weather Trains

The tropics are now in full throttle and as of today we have Hurricane Danielle, Tropic Storm Earl, and a new wave coming off the coast of Africa. Those three systems are all from Africa and are what is called Cape Verde type systems. There is also a low pressure system in the Gulf of Mexico but nothing tropical at this time.

Hurricane Danielle
During the night, Danielle had lost some of its strength and was downgraded to a Tropical Storm but it has gradually gotten better and is now back to Hurricane status. Danielle is headed NW and soon will slow down it forward speed. Danielle is expected to make a northward turn within 48-72 hours. Danielle has a very good CDO, but there is a little southwestward upper level winds entering the core of the system but will be relaxing very soon.

Tropical Storm Earl
Tropical Depression Seven has been upgraded to Tropical Storm Earl. TS Earl has been gaining strength during the day and is forecast for gradual strengthening and be a hurricane in about two days. Earl has been on a somewhat westward direction and should continue this track for about 3 or 4 days. Earl has been taking the same track as Danielle and whether or not the cooling of the churned seas from Danielle will affect the strengthening is still up the air. The models do want to take Earl on a NW track in about 5 days. This is all going to depend on how strong Danielle will be for the next couple days. A strong Danielle will help keep the ridge and allow Earl to head northward. If Danielle stays as a minimal hurricane or tropical storm, the ridge might close up thus making a more W to WNW track. I feel the models have not grasped what Danielle strength will be, and the forecast might be off. I hope I am incorrect and Earl heads out to sea and with no one in his sights.


Invest 96L

The latest tropical wave that has exited of the coast of Africa has now been designated as 96L. This system has been showing signs of organizing and is expected to become a least a tropical depression within the next few days. This wave is following Hurricane Danielle but it is far away enough so that the two don’t interact each others flow.

Although the models seem to have 96L following the path that Hurricane Danielle – it is a little early to have that in stone. The forecast for Hurricane Danielle is simple. Danielle will be picked up by a large trof from the the east coast of the US due to a weakness in the ridge. That will allow Danielle to be head NW then NNW and away from the US coast and probably Bermuda. The caviate is that once Danielle is picked up by that weakness in the ridge, later the ridge MAY build back and that may not allow 96L to be picked up. It’s just to early to see what will happen. If it is not picked up, then the East coast of the US may be affected.


Tropical Storm Danielle

The expectations of what was TD Six has now been upgraded to TS Danielle at 5:00PM. During the day today, a lot of strong thunderstorms with some very cold cloud tops…some down to -85°C, made the forecasters at the NHC to make the upgrade. The colder the cloud tops – the better for storm development. The visible satellite shows that Danielle is continuing to experience the moderate shear from the east and southeast. This will be relaxing within 24-48 hours and this will allow Danielle to intensify to at least minimal hurricane status. Later, some of the models want to bring Danielle to a major hurricane. This will only be for a short period of time as the forecast is for vertical shear will begin to erode the intensification.

Although during the day today Danielle the movement was a bit northward, it has returned back to WNW and should stay that way for 48-72 hours. After that a break in the subtropical ridge will allow Danielle to head NW and away from the US coast. Depending upon how long Danielle continues the WNW movement, Bermuda may be affected.


Invest 95L

A wave that rolled off Africa a few day ago has been designated as Invest 95L. This is a system that has a very good chance to be a tropical depression within 48 hours. Invest 95L has very good cyclonic turning and it has a very moisture envelope.

(ADDENDUM – as of 5:00pm 8/21 Invest 95L developed enough to be classified and designated as Tropical Depression Six)

In the water vapor image above, you can see there is some dry air to the north of Invest 95L. The forward motion of 95L is W-WNW and this should allow the system to not be hindered by the dry air. Below is an image of Wind Shear analysis. The wind shear at the moment is not to bad for the system, but it is not allowing any development. The environment for 95L is going to be changing and the wind shear will be very low. Forecast is for better conditions overall.

The forecast for 95L is that it will develop into a tropical depression by sometime Monday. All models do want the system to turn NW then N and eventually curve out to the sea and away from any land masses. The problem is exactly when it will do so.

The intensity in the models seem to keep 95L in the yet to tropical storm range (at least for 48 -72 hours) for when it does develop. An outlier does want to have 95L into a hurricane but that is will have to be shown later on. Until the system fully develops, I would take the model intensity with a grain of salt.


TD Five reborn?

The remnants of Tropical Depression Five and had crossed into LA and moved across the Gulf states, now has a chance to redevelop as a depression again. The storm is headed south/south-westward and may develop as soon as Tuesday. Both satellite and Radar is showing a band of very intense thunderstorms.

A few models are forecasting that the remnants of ex-TD Five will approach the Gulf coast and begin to develop to at least a tropical depression. If the storm is far enough into the warm waters, and enough time, it may have a chance to develop into a weak tropical storm. Shear is very low 5-15 knots and the regeneration of the storm should occur and if so landfall somewhere around Southeast Louisiana between late Tuesday or Wednesday.


Tropics Unusually Quiet…for now

With EX-Tropical Depression Five still hanging around the Gulf Coast and a few models want to bring it SW and back into the GOM for possible re-emergence and even worse, possible tropical redevelopment – I can’t say that TD#5 has dissipated. Hopefully that forecast will be bust.

Although, the tropics are somewhat quiet, there are a few systems that will be coming off of Africa that still need to be watched. These waves are somewhat large and at least one may have a chance to develop. The wave further to the north, will probably have problems with the SAL and also it will probably recurve out to the north. The other wave, just to the east of the first wave, is forecast to to head WSW and will be closer to the ITCZ and away from the SAL.

This second wave, once it exits of the coast, this may have a good chance to develop. The MJO (the green in the graphic) in the Eastern Atlantic is in a upward motion which should help in the development.

For the next month or so, the tropics will be at their peak, so storms will start to roll off off like trains, hopefully though none will have the chance for any landfall.


Invest 94L

An area of low pressure has been designated as Invest 94L. This area is located off the eastern coast of Florida, near Jacksonville. Invest 94l is moving WSW and will continue to track this way for 12-24 hours. Although it is very difficult to see on satellite imagery it is roughly located at 29° N – 79° W. (Note in the satellite images, Invest 94L is not the large area of convection south of the panhandle of Florida)

Some models want to take Invest 94L westward over the state of Florida and then begin to develop in the NE GOM near the panhandle, then head WNW. Some models have it as nothing but a tropical depression, yet there is another wanting it to develop into a hurricane. Until Invest 94L has entered and into the Gulf – there is no way of knowing.


Invest 93L

Yesterday, the tropical wave that come off of Africa was designated as 93L. This system has a high chance of developing into a tropical depression within 24-72 hours. The upper level winds are low, the SST’s are warm therefore the atmospheric conditions are conducive for continuing development.

Most of the models tend to take 93L NW for a short period due to a weakness in the steering flow. Following that period, there is a little disagreement on how far west 93L will go before it will begin to turn NNW and then N. This system will probably not be threat to any land masses and will just be a shipping hazard.