Upcoming week - June 18-24

[Andrew92]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Evaluating last week

This past week I again predicted no tropical cyclone development, but made a note that things may try to come together a bit in the western Caribbean after studying the models going into the prediction. Indeed, nothing has developed tropically this week, but there is some interesting weather blossoming over the western Caribbean, that may eventually develop further. But as it stands, there is not even an Invest out of this, and so for the second consecutive week my grade is an A.

Hey I’m on a winning streak! Let’s put it on the line and look at this new week.

Current situation and models

Before looking at the western Caribbean, it would be wrong to overlook an area that the National Hurricane Center is highlighting for some possibility of development. That area is a low pressure system just north of Bermuda, very recently christened as Invest 95L. It does look well-organized, but is non-tropical at this point, doesn’t have much in the way of thunderstorms, and is heading northeastward into cooler waters. I would think if a named system did come out of this, that it would be subtropical only, never reaching full tropical characteristics.

Now on to the western Caribbean. Several reliable models are picking up at least a broad low pressure area in the Bay of Campeche for later in the week, heading towards Mexico or Texas. However, earlier models indicated a more significant system; those trends seem to be showing a weaker system now. The lowest predicted pressure I have so far seen is about 1004 mb. One thing I have learned is that “the trend is your friend,” and so it may be that a weaker system may rule the day. But that doesn’t mean it won’t be destructive. Look at Allison in 2001 for a broad, disorganized system and tell Houstonians it wasn’t a big deal, at your own risk! Development, if any, is unlikely to take place until at least Friday, as the system is currently very disorganized, shear is pretty strong in the area though I believe forecast to relax, and there may also be some land interaction with Central America. But a favorable MJO also appears to be in the cards, which may help stir something up by week’s end.

Recent history

Since 1960, these storms have developed or occurred during this upcoming week:

An unnamed storm in 1960
Brenda in 1968
Candy in 1968
Agnes in 1972
Ana in 1979
A subtropical storm in 1982
Bonnie in 1986
Arlene in 1993
Arthur in 1996

Of these nine storms to occur, only Brenda, Agnes, and Bonnie went on to become hurricanes, all reaching Category 1 at peak strength. Candy and the 1982 subtropical storm did come close though, reaching 70 mph winds at their peaks. Candy, Agnes, the subtropical storm, and Bonnie all occurred in the Gulf of Mexico. Candy and Bonnie hit Texas, while Agnes and the subtropical storm hit Florida. Brenda was more unusual, forming off the southeast coast and tracking eastward out to sea. It should also be noted that Bonnie became a hurricane on June 25, whereas this prediction reaches to the night of June 24.

As for the others, the unnamed storm in 1960 and Arlene also occurred in the western Gulf of Mexico and hit Texas as minimal tropical storms, and were more of rain events than anything else. Ana developed east of the Windward Islands into a moderately strong but short-lived tropical storm, topping out at 60 mph. Arthur followed a similar path to Brenda, but was a much weaker, minimal tropical storm that edged the Outer Banks before heading out to sea.

So when looking at prime areas, six tropical storms occurred in the Gulf of Mexico, with two as hurricanes and two others coming close. Four of these hit Texas; the other two hit Florida. Meanwhile, two other storms formed near Florida and the Bahamas and both re-curved quickly. One became a hurricane and one remained very weak. One other anomalous storm formed east of the Caribbean. Exactly zero storms in the satellite era have formed north of Bermuda. Interestingly, only Agnes of this set formed in the western Caribbean, but before June 18.

So what does this all tell us?

OK, Invest 95L north of Bermuda. Impressive as it may look, models and history are not on the side of tropical or even subtropical development with this system. Traversing cooler waters also will not help matters on that front, pardon the slight pun. Therefore, I’d be surprised if Chris came out of this system.

The area over the western Caribbean is more complicated. Models have tried to get something going here for the last two weeks, but nothing has really come except for this mess of thunderstorms. It may yet become an Invest, but the models have shifted recently towards now developing something closer to the Bay of Campeche, and heading for Mexico and/or Texas. This development would likely happen no earlier than Friday, and would be a broad system, likely not particularly intense in winds. But history would support such a scenario, as two thirds of all storms since 1960 during this upcoming week have happened in the Gulf of Mexico. Two thirds of these Gulf of Mexico storms have also been in the western part, heading into Texas.

The prediction

The last two weeks were successful in being not ready to bite on models picking up on development in the western Caribbean. I am not so sure about that this time around, however. I agree that development into a tropical depression and/or storm will take until at least Friday, and it will be in the Gulf of Mexico or Bay of Campeche. With the models trending downward in intensity, I think the best analogs for this supposed system may be the 1960 unnamed storm and Arlene in 1993. It likely won’t be very strong, but could cause bigtime flooding headaches to Mexico and Texas. I predict a tropical depression to develop sometime on Friday in the western Gulf of Mexico. As a broad system, it will be slow to develop, but become Tropical Storm Chris in the afternoon or early evening on Saturday as it nears the coast of northern Mexico. Chris will make landfall by Sunday morning with maximum winds of 40-50 mph and then dissipate later that day in the Rio Grande Valley. Rainfall will be heavy in northern Mexico and lower Texas, especially near the Rio Grande. Wind, surge, and surf impacts will be minimal. Confidence is 50%.

Elsewhere, I predict no tropical or subtropical development north of Bermuda from Invest 95L or anywhere else in the Atlantic this upcoming week. Confidence is 90%.

-Andrew92

**EDIT: Was informed after posting that the system north of Bermuda has become Invest 95L. Thank you Cycloneye!

[cycloneye]

Hi Andrew. Another great discussion. I have to tell you that the Bermuda area is now invest 95L so if you want to add that to the post, go ahead.

[Andrew92]

Thanks Luis! Yeah that must have just happened, as I had been away from the computer for the past 4-5 hours or so and it wasn't an Invest then. I updated the post to reflect Invest 95L for north of Bermuda. Still not buying further development, though.

-Andrew92

[Andrew92]

Well with the 11 PM advisory up for Debby, time to evaluate.

The first two weeks were very good. This past week was not so successful. For one thing, I didn’t predict Invest 95L to develop further, and it not only became Chris but even became a hurricane briefly. Now I never would have predicted a storm that intense to begin with anyway, but as it stands, not predicting any development for this system was simply a botched prediction.

However, I did have kind of a handle that something would form in the Gulf of Mexico coming into the weekend. In fact, the timing for intensification into a tropical storm for Saturday afternoon or early evening was spot-on, with the first advisory as a 50-mph storm at 5 PM. But I was thinking this would be further west, closer to Mexico and Texas, not near Florida. The motion I predicted was also northwestward, but Debby (would have been Chris if not for Invest 95L) decided to go slowly northeast. The system is very broad as anticipated, and the primary threat of heavy rain has been warranted – again, in the wrong location. But surf has also proven to be a major factor in Florida today, but then again Debby has also gotten a tad stronger than I expected, possibly furthering that effect. I had predicted peak intensity of 40-50 mph, but it is currently at 60 mph instead.

All in all, this was a week for the birds. But you know something? Remember when I had that dream of Chris out in the Atlantic, and Debby in the Gulf of Mexico threatening Florida? Why did I not listen to that? If I had gone with that past dream as part of my analysis, I may have had more bias, but my grade might have been about an A- or so (since I never would have expected a hurricane from Invest 95L/Chris, docking me from an A). But for not listening to my intuition (silly as it sounds) and giving in to models that failed me… OK this week was difficult but my grade is still a D.

Upcoming week coming shortly.

-Andrew92