Vigorous tropical wave bringing rain to portions of Central America

Invest 93L in the northwest Caribbean Sea. Most computer models indicate a track across Central America and in to the Bay of Campeche this week.

Invest 93L in the northwest Caribbean Sea. Most computer models indicate a track across Central America and in to the Bay of Campeche this week.

The NHC has increased the probability of development for the tropical wave passing over portions of Central America to 40% this morning. Showers and thunderstorms have steadily increased with the system over the past 24 hours and if it were not for the land mass in its way, it would be a depression by now.

As it stands now, there is quite a bit of land in its way and this will preclude any significant development for the next day or so. There is a chance that the wave energy emerges in to the Bay of Campeche where it will have a chance to develop in to a depression or tropical storm.

Most of the computer guidance suggests that a track over the extreme southern portion of the Bay of Campeche is likely before finally reaching Mexico again on the western side of the bay later this week.

Water temps in that region are plenty warm and upper level winds are becoming more and more favorable. It won’t take much for this system to become a tropical depression or even a moderate torpical storm if it can get free of the land interaction it is dealing with now.

The main impact right now will be heavy rains for areas of Central America, including Belize and the Yucatan. This will spread westward over the next few days and it is possible for several inches of rain to fall across the region.

As for any possible impacts to the U.S. go, we can thank a fairly strong ridge of high pressure to the north of the tropical wave for keeping it on a general westward course. None of the computer guidance indicates that it will gain much latitude this week and so it appears that even south Texas will remain clear of any ill-effects from this weather feature.

The rest of the tropics, including the east Pacific, are nice and quiet as we begin the week. I’ll post more here this evening.

M. Sudduth

Ernesto about to make landfall along Yucatan while the rest of the tropics remain fairly active

Hurricane Ernesto is only hours away from making landfall along the eastern coast of the Yucatan. Top winds were last reported at 85 mph with higher gusts. The pressure has fallen all day and as of 8pm ET was down to 980 mb. From the looks of the size of the hurricane, it is a good thing that Ernesto had so many problems intensifying as it could have turned out to be a powerful hurricane.

As it stands, the effects will be pronounced but not severe. That is to say, we should not see the kind of damage that a much stronger Caribbean hurricane would cause (obviously). However, because Ernesto is currently in strengthening mode, it will likely have more damaging wind gusts than would a weakening or steady-state hurricane. This is due to the convection or thunderstorm activity reaching up in to the wind field, bringing the strong winds down to the surface in downbursts within the heavy rain. Anyone who has been through and intensifying hurricane knows what I am talking about. It’s not pleasant but at least Ernesto is not a major hurricane.

The fairly quick pace of movement will get Ernesto inland and weakening rather quickly and thus the rain threat will not be too bad. However, any tropical rainfall that is dumped over an area can produce flash floods and mudslides along hilly terrain. We’ll hope for a quick transit of Central America by Ernesto, thus lessening the overall effects.

Elsewhere, the east Pacific has a new named storm, Gilma, but it is forecast to track generally westward and away from land, so no worries there.

In the tropical Atlantic, we’ll be watching things closely as invest area 92L marches west and a series of large, organized tropical waves move off over the coming days. There is pretty good agreement among the major computer models, the ones that predicted almost exactly what Ernesto has done up to now, that we’ll see development between Africa and the Lesser Antilles over the next few days. In fact, I would not be surprised to see two or three systems get going over the next week to 10 days. Keep in mind that there is no evidence to suggest any threat to land areas, not yet. So even though some of the long range guidance might be interesting to watch, it is to be considered only for “hmmm” value and nothing more. We know we are entering the peak time of the hurricane season is that it is time to watch things a little closer. As far as getting worked up over something in the long range models? There’s no use in doing so, just keep up to date and what ever happens, happens. We’ll know in plenty of time for people to react if need be.

I’ll have more here tomorrow including a continuation of the daily video blog for our new HurricaneTrack app for iPhone. I’ll also be announcing plans for our first update to the app in the coming days as well as progress on the Android version.

94-E in the southeast Pacific looks likely to develop in to a tropical storm

East Pacific Invest Area 94-E

East Pacific Invest Area 94-E

The only area of concern today continues to be invest area 94-E located in the southeast Pacific, just off the coast of Central America. As you can see in the satellite picture (courtesy of the University of Wisconsin’s CIMSS site), the low pressure area is gradually becoming better organized. The red “I” indicates the initial position of the center of the low. There is some banding of the cloud cover and deep tropical convection is maintaining itself. A majority of the reliable computer models indicate that 94-E will move WNW to NW and approach the southeast coast of Mexico in a few days. As far as intensity goes, the SHIPS model indicates category one hurricane strength, assuming that the center does not interact with land. Other intensity models are more conservative, keeping the system a moderate tropical storm at its peak.

The main impact looks to be heavy rain fall for portions of Central America and eventually southeast Mexico. The disturbance is slow moving, so it has time to dump a lot of rain along its path. Interests in the region should be aware of this hazard.

In the Atlantic Basin, things are nice and quiet. It is possible that we may see a window of opportunity for tropical cyclone formation in about a week but the only evidence of that right now is the fact that the MJO phase would be more favorable. This alone does not lead to development- there are plenty of other factors that ultimately drive the genesis of tropical storms and hurricanes. We’ll see what happens as we move towards the latter half of the month. So far, I do not see any consistency in the long range model guidance to suggest development in any location. I’ll post more about 94-E tomorrow morning.