Storms - Ernesto

[Smiling JOe]

So now that the storm is named, I think it deserves its own thread, in case people don't know what invest 97L was all about.

Ernesto gets its name

Posted by: JeffMasters, 5:16 PM EDT on August 25, 2006

The Hurricane Hunters visited Tropical Depression Five this afternoon, and at 1:30pm EDT found a surface circulation center and maximum sustained surface winds of 40 mph, making this Tropical Storm Ernesto. Visible satellite images from this afternoon show a a sheared system, with the low level circulation center completely exposed. Upper level winds from the northwest are creating 10-20 knots of shear, which is keeping all the heavy thunderstorm activity confined to the southeast (downwind) side. However, this heavy thunderstorm activity is building towards the center, and the storm has some solid spiral bands forming. The storm is intensifying in the face of the shear. Radar from Aruba shows some of the outer spiral bands.

Figure 1. Current satellite image of Ernesto.

The models
The latest 12Z (8am EDT) model runs are in, and they portray a conflicting picture of what may happen. Three of the four major global models--UKMET, GFS, and NOGAPS--dissipate or severely weaken the storm by Monday. The Canadian model, which has been the most aggressive in making Ernesto a hurricane in the Gulf of Mexico, now keeps the system a weak tropical storm all the way to landfall in the Florida Panhandle on Tuesday. The European Center model has a similar forecast. Oddly, the large upper-level trough of low pressure over the central Caribbean is forecast by these models to move west away from Ernesto, and an upper level high pressure system to build on top of the storm. This situation should act to lower the shear and aid in intensification, and that it what the official NHC forecast is calling for. It is unusual for the models to forecast a favorable shear environment, yet dissipate a storm, and serves to show the limitations of these models in making hurricane intensity forecasts. I have very little confidence in any of the Ernesto intensity forecasts--including the official NHC forecast of a hurricane in the Gulf of Mexico on Tuesday. High wind shear could still destroy this storm on Sunday. Ernesto should slowly intensify through Saturday, but beyond that, I have no idea. It's best to prepare for the worst, and hope for the best. All portions the U.S. coast from the Florida Keys to Brownsville, Texas are at risk from this storm.

Given the high degree of uncertainty in Ernesto's intensity, those of you traveling to or from Jamaica, Cuba, the Cayman Islands, and Cancun should play "wait and see" as long as you can. At this point, it is likely that Jamaica, eastern Cuba, and southwest Haiti will get tropical storm conditions on Sunday. Jamaica's airports will probably close about 2am Sunday, and remain closed into late Sunday night. Ernesto probably does not have enough time to intensify to a hurricane before reaching Jamaica. Airports in the Cayman Islands will probably close by late morning on Sunday, and reopen Monday afternoon. Ernesto could be a Category 1 hurricane for the Caymans.

Funny that State Farm Insurance companies sponsor the map above, yet they are not issuing policies for most people whom the storm is likely to affect.

 

[pgurney]

A little more detail of the GFDL model (red line on the top map).

 

[Smiling JOe]

The discussion this morning on Ernesto is not very comforting. Here is an excerpt from that discussion.

"ALL GLOBAL MODELS DEVELOP AN UPPER-LEVEL RIDGE OVER ERNESTO...A PATTERN WHICH IS CONDUCIVE FOR STRENGTHENING. THIS UPPER-LEVEL PATTERN COMBINED WITH THE VERY WARM WATERS AHEAD OF THE CYCLONE COULD LEAD TO SIGNIFICANT STRENGTHENING OVER THE NEXT FEW DAYS. THIS COULD RESULT IN ERNESTO BECOMING A POWERFUL HURRICANE IN THE GULF OF MEXICO."

Bummer!
Tropicwatch

from invest 97L thread

 

[pgurney]

Holy cow! Would you look at the 11:00 am updated map?

 

[bsmart]

That is horrible.

 

[bamcon]

Thanks for the update on Ernesto. We are planning to come to Inlet Beach next weekend, so this is informative. We will check back later to see how Ernesto is progressing.

 

[kingfishn]

Here's a good tracking program with online updating/plotting, forecast, strike probabilities and historical data....as well a preparedness 'stuff'...think it
costs about 20 bucks...

http://www.hurricanesoftware.com/

 

[Smiling JOe]

The Hurricane Hunters found a strengthening Tropical Storm Ernesto this morning. Their final report at 5:30am EDT had a pressure of 997mb, good enough for 50 mph winds at the surface. Water vapor satellite loops show a large upper level low forming over the western Caribbean, and this low is moving westward at nearly the same speed as Ernesto. Counterclockwise flow of air around the upper low is causing 15-20 knots of shear over Ernesto, and this can be seen in the water vapor loop and visible satellite loop causing a flattening of the clouds on the west side of the storm. However, the overall appearance of Ernesto on satellite imagery is slowly improving, with upper-level outflow developing on the east side, and more low-level spiral bands forming. Long range radar animations from Puerto Rico show these spiral bands. Rain amount of 1-3 inches have fallen across the island so far today, with isolated totals as high as 8 inches. As long as Ernesto does not grow any closer to the upper level low to his west, slow intensification should occur the remainder of today.

As Ernesto passes south of Haiti today, the mountainous southwestern peninsula could experience life-threatening flash floods. This is common in this part of Haiti, even for modest tropical storms. Deforestation of the hillsides has left them little protection from floodwaters.

Figure 1. Current storm total rain in Puerto Rico.

The intensity forecast
The latest 06 GMT (2am EDT) model runs are in, and they again portray a conflicting picture of what may happen. Two of the four major global models--UKMET and GFS--dissipate or severely weaken the storm by Monday. However, the other two major models, the NOGAPS and GFDL, foresee a major hurricane in the Gulf that hits the Florida Panhandle on Friday. The Canadian model takes a major hurricane to the Louisiana coast on Friday. It appears that the two models poo-pooing Ernesto--the UKMET and GFS--are not doing a good job initializing the storm, and this is causing an overly optimistic weakening. Ernesto is holding his own again the shear, and is much stronger today than these models were predicting in their runs yesterday. The NHC official forecast of a continued slow intensification into a Category 1 hurricane by Monday seems like a reasonable one. After that, an explosive deepening phase into a major Category 3 or 4 hurricane is certainly plausible, given the very warm waters and low wind shear forecast to develop. However, keep in mind that our computer models are very poor at forecasting the behavior of upper-level lows in the tropics, and the upper low to the west of Ernesto could easily be in a different location and bring significant shear to the system. In addition, intensity forecasts more than 48 hours out are very unreliable. Witness some of the intensity forecasts for Debby made two and three days ago, which called for her to be a Category 1 or 2 hurricane today. Today, Debby is a tropical depression on the verge of dissipation. With all that said, I believe that Ernesto will be a major hurricane in the Gulf of Mexico at some point.

Jamaica, the Cayman Islands, and Cuba are going to get a pounding from Ernesto as he approaches hurricane strength Sunday and Monday. Washed out roads, downed power lines and trees, and minor roof damage will be common in those islands. Ernesto is under too much shear and does not have enough time to intensify into more than a strong tropical storm or weak Category 1 hurricane before affecting those islands, and the full force of Ernesto is likely to be reserved for the U.S. Gulf Coast. Those of you with plans to be in Cancun or Cozumel can expect a day or so of airport closures due to high winds between Monday night and Tuesday night.

The track forecast
As Ernesto crosses into the Gulf of Mexico on Tuesday, a trough of low pressure will be swinging across the eastern U.S. and should pull the storm on a more northerly track. Most of the models are showing that this trough will be strong enough to bring the storm all the way to the coast between Louisiana and the Florida Panhandle. However, the trough may not be strong enough to do this, and Ernesto could get stuck in the Gulf for a week, potentially heading westwards towards Texas as a new ridge of high pressure builds in. A subsequent trough could then turn the storm northwards into the coast at some later time. The UKMET model and GFS model prefer this solution. At this point, there is not enough information to say which solution is most likely, and residents from Texas to the Florida Keys need to be prepared for this storm to affect them.

The next system?
A large tropical wave with plenty of spin came off the coast of Africa yesterday is currently over the Cape Verde Islands. Some of the computer models forecast that this wave will develop, but this is very unlikely for at least the next three days. The Saharan Air Layer analysis is showing a large amount of dry air spiraling into the center of this wave. There are currently no other threat areas to be concerned with. In the long range, the GFS is forecasting a very busy first week of September, with two or more tropical storms developing between Africa and the Lesser Antilles.

 

[laurawood]

looks like a hurricane party may be in order, no???

 

[Beach Runner]

Who would party in the face of a major loss other than those who have nothing to lose? We laughed about hurricane parties when we lived in NOLA, but we were students then, so it would have no impact on our lives.