Upcoming week - August 29-September 5 (Extended for Labor Da

[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 meterological data. It is NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Warning: This one is a bit long.

Evaluating last week

Well, this week was pretty much all about Hurricane Irene. My review for this previous week is very mixed. Generally speaking, I had the idea of the track down, with a track near Hispaniola, into the Bahamas, and north from there and re-curving. As I also recall, at the time I made this write-up, there were some models still taking Irene inland further and not really re-curving. The timing of track for the first couple days was also very rock-solid, as I predicted Irene to impact the southern Bahamas on Wednesday, and the northern Bahamas on Thursday. Another major victory was the peak intensity. A lot of models and forecasts kept insisting that Irene would become a very strong C4 hurricane of some sort; however, I wasn’t buying that and went with a C3 hurricane with maximum winds reaching maybe as high as 125 mph. The winds indeed got no higher than 120 mph. Finally, while the location of landfall was far off, it is worth noting that I correctly nailed the time of US landfall, on Saturday morning.

Now for the flaws. I had Irene passing over Hispaniola, but it passed to the north. This also affected the intensity portion a little, as I had Irene weakening to a tropical storm while over there. It is true that Hispaniola still disrupted Irene a little bit, and Irene was only a short distance off Hispaniola and produced some heavy rainfall, as I predicted. But staying offshore allowed Irene to maintain hurricane intensity even when it was somewhat disrupted. The re-strengthening was at first slow as I anticipated, but then Irene ramped up really quickly into a C2 and later C3 hurricane on Wednesday, when I said this would happen on Thursday – again, this is likely a consequence of staying off of Hispaniola. While I did correctly predict no further intensification from there, I did not foresee Irene undergoing as much shear and dry air as it did, and Irene weakened a lot more before US landfall than I could have predicted. I predicted a C3 at landfall, but Irene was a large C1 with winds of 85 mph at landfall. Finally, Irene tracked a fair distance east of what I predicted, showing I probably need to learn more of the model trends coming into the week, rather than just what the models are saying at the time. The models were congregating on South Carolina and I agreed, but the trend was shifting eastward. This will be a lesson I will apply for the future: “the trend is your friend.” I had predicted hurricane conditions in Florida, but the storm brought some rough surf, rain, and light winds – no hurricane winds. The storm also made landfall in North Carolina – one state off of where I predicted. I also didn’t think Irene would move quite as fast to the north as it did after landfall.

Overall, evaluating how I did with Irene, it was very much far from perfect; however, I had plenty of victories with this storm. Some were easy such as the track and timing through the Bahamas, but others were more difficult. Intensity remains the most difficult aspect of tropical systems to nail down; to at least nail down what the maximum intensity would be in the face of lots of predictions for a stronger storm is definitely something I will give myself a lot of credit for. With this all said, I probably did as well of a job with Irene last Sunday with what I had to work with, but it again was still not that great. I will give myself a C overall for this storm.

There was other activity besides Irene, however. Harvey was dissipating in Mexico, and while I did predict a slight re-strengthening before landfall and it didn’t, the effects were still probably the same as if it had done so. I predicted no other developments during the week. Some were very surprised that I made that prediction, and it was indeed wrong. However, it took a fledgling tropical depression that just could not get going, and an Invest that had almost no chance of developing that developed into Jose anyway that did it; it’s not like it was some intense storm becoming a hurricane that tripped me up. Incidentally, there were some predictions of TD 10 to become a stronger storm, even a hurricane. If there’s one thing I could learn a little more, it’s picking up those weak ones that never seem to get going. But overall, the damage for this part of the prediction could have been much worse, and I will give myself a B- for this area.

The B- gets little weight though, and Irene was the bread and butter. I already gave myself a C there, and the B- for everywhere else does not make this a C+ week. My grade for this past week will be a C.

Now we get an extended week to account for the upcoming holiday weekend. Any more threats to look at?

Current situation and models

Jose is the only active tropical system, and it is on its way to dissipating tomorrow. No model does anything else with this storm besides let it die out, so anything other than that would be a tremendous surprise.

I can absolutely promise you this week, that I will definitely be predicting a development for Invest 92L. It is too well-organized and too many models do big things with this disturbance not for me to predict further development. The BAM models apparently do not create much out of this system and keep it further south. However, the global models, such as the Euro, GFS, UKMET, and NOGAPS, all develop Invest 92L into a significant storm, meaning a hurricane or even stronger. All of these models also have another thing in common: the track. Pretty much all of these models, after developing this system, re-curve this potential storm north and out to sea. Some, like the GFS, re-curve it further east. However, the Euro takes this system north of the Caribbean, though by a safe distance. While a fish seems like a decent enough prediction, one must remember that, as I said above, “the trend is your friend!” It would not be unreasonable for a westward shift in track. Bermuda could also easily be in the crosshairs for a visit from potential/probable Katia. Then again, the eastward re-curving models may have some merit, as TD 10 turned north east of 40 degrees. There is also a very large weakness between ridges in the Central Atlantic, and a fast developer might have a very easy time re-curving north, but could still pose a threat to Bermuda beyond Labor Day. However, Joe Bastardi is also predicting another East Coast threat in about 12-16 days – outside this period and a long ways off, but compelling as it indeed could come from this disturbance.

The remnants of TD 10 are still out there, but unfavorable upper-level winds and cooler waters should preclude any further development. Then again, Jose developed…

Also important to bring up is that a lot of the global models are also showing some sort of development in the Gulf of Mexico later in the week. Whatever comes out of this looks like it would be kind of broad, probably not particularly intense. One also has to remember there is a very strong ridge of high pressure in that area, though a lot of the models do break it down. As a result, it would seem that the track would be towards the north into Texas or Louisiana, and this is corroborated by models like the Euro, FIM, and GFS, which track a storm in that direction, possibly striking next Tuesday or so. That would be for next Monday, but the proposed storm is still one that needs to be looked at very closely.

Finally, there are some hints from the NOGAPS of one more system off the coast of Africa on Labor Day itself. It’s a long ways away, but we’ll consider it as it is that time of year to look out there, after all. There is little to no model support for this at the end of the week, but being a long ways off will lower confidence a little.

Recent history

We’ll start with the Main Development Region. This storm is situated south of 15 degrees latitude, and east of 30 degrees longitude. It will remain east of 30 degrees for a couple more days. Storms whose incipient depression have developed south of this latitude, east of this longitude, during this upcoming week include:

Donna in 1960
Frederic in 1979
Frances in 1980
Gabrielle in 1989
Isidore in 1990
Luis in 1995
Ivan in 2004
Josephine in 2008

There are plenty of big names among these eight storms! Of course, remember I’m talking they became a depression south of 15 degrees and east of 30 degrees; some of these became storms further west. That latter category includes Frederic, Isidore, and Ivan. Of major note is that only one of these eight storms failed to become a hurricane: Josephine, which was over waters churned by other previous storms, namely Ike. Also, only one other storm did not become at least a C3 hurricane: Isidore, which just had little chance as it quickly re-curved to the north.

As for the tracks of these storms, four tracked to the west-northwest across the tropical Atlantic and reached the Caribbean in some way. Those storms were Donna, Frederic, Luis, and Ivan. Josephine also tracked in that way, but coming off the heels of Ike made it pretty much impossible to pose the same kind of threat these other four did. Then again, Frederic was coming off the heels of David, and survived. Two of the storms, Frances and Isidore, quickly re-curved – in fact, Frances was only briefly a C3 hurricane in 1980. Gabrielle split the middle, went further west but did not reach the Caribbean. Basically, the only storms heading that likely way not to be major hurricanes at the time were Frederic (off the heels of David, but became one much later) and Josephine (off the heels of Ike). Donna, Luis, Ivan, and Gabrielle were not just C3 storms either; these all became very strong C4 hurricanes before they reached that area, with winds at a minimum for any of these storms at maximum being 135 mph before reaching there (Ivan).

Now let’s move to the Gulf of Mexico. Storms developing there during this upcoming week include:

Delia in 1973
Caroline in 1975
Anita in 1977
Babe in 1977
Elena in 1979
Elena in 1985
Debby in 1988
Earl in 1998
Fay in 2002
Grace in 2003
Henri in 2003
Hermine in 2010

Twelve storms have developed here since 1960; of this bunch, six became hurricanes, or half of them: Caroline, Anita, Babe, 1985 Elena, Debby, and Earl. Delia and Hermine also were very near hurricane intensity when they made landfall, and Fay was at least intensifying and just ran out of time. Then there are the weaker ones, 1979 Elena, Grace (often nicknamed “disGrace” and ridiculed by quite a few as not even being a cyclone), and Henri. However, 1979 and 2003 did prove, either earlier or later, that the Gulf of Mexico could sustain developing storms those years, so those storms are probably anomalies (in the minds of many, that would be a compliment for Grace).

As for the tracks, Delia, Caroline, Anita, 1979 Elena, Debby, Fay, Grace, and Hermine all hit either Texas or Mexico – eight out of twelve. However, only three of these became hurricanes. Babe hit Louisiana, 1985 Elena did its famous loop near Florida before hitting Mississippi, Earl hit the Florida Panhandle after developing in the Bay of Campeche, and Henri fizzled into the Florida Peninsula. Only Henri failed to become a hurricane in this tiny sample.

Finally, the following years had at least two storms develop in the Main Development Region during this upcoming week (with the number, names, and anything asterisked which eventually became a hurricane):

1961 2 (Betsy* and Debbie*)
1964 2 (Ethel*, and Florence)
1967 3 (Arlene*, Beulah*, and Chloe*)
1979 2 (Frederic*, and Gloria*)
1980 2 (Earl* and Frances*)
1996 2 (Gustav, and Hortense*)
2008 2 (Ike* and Josephine)
2010 2 (Fiona, and Gaston)

There are a surprising 12 asterisks out of 17 storms. Granted, the storm that may come at the end of the week would have to wait until later to become a hurricane, but it absolutely cannot be discounted at this point.

So what does this all tell us?

With Invest 92L any minute now to forming into a depression and not off the heels of anything, the odds are very good for intensifying into a very strong hurricane and possibly threatening the Caribbean. While some models have initially re-curved this disturbance, the Euro has been further west, and these other models appear to be shifting west. I will say it again, as we learned from Irene, “the trend is your friend.” Well, unless the trend eventually hits you I guess. I think the Caribbean will really need to watch this one, particularly the Leeward and Virgin Islands, possibly Puerto Rico too. Incidentally, while I didn’t say this above, of the Caribbean storms, only Ivan didn’t hit that part of the Caribbean – Donna, Frederic, and Luis all did. Beyond that may be for next week, but Joe Bastardi’s implication for another East Coast threat in 12-16 days could be this one if he’s accurate. However, that large weakness between ridges is also cause for thinking this may miss the Caribbean altogether, as Gabrielle in 1989 did.

In the Gulf of Mexico, if the models are to be correct about a development in the Bay of Campeche, it would seem like it would head toward Texas or Mexico. However, the global models like this proposed storm to take a northern track. One thing seems sure though: anything that does form would not do so until the weekend and probably be a very broad, diffuse system. It will probably take as much advantage as possible of its environment though, and at least a strong tropical storm needs to be considered. If the eastern path is taken, the odds *might* be a bit higher for a hurricane, but the sample sizes above were very small. Most models, if not all, do not predict a particularly strong storm out of this thing though. Landfall anywhere could also easily occur on Tuesday, which would therefore not apply for this upcoming week and next weekend.

Finally, it is imperative to consider another development off Africa at the end of the week. History says it can definitely happen, and the NOGAPS likes it. However, I am not seeing any other models supporting this right now.

The Prediction

First, let’s do Jose. I predict Jose will weaken to a tropical depression on Monday, dissipate overnight into Tuesday, and never re-develop. Confidence is 90%.

That was easy. Now it gets much harder. Invest 92L is almost sure to develop in the next day or two. With a current 70% chance of development, I would have to think the depression will form develop tomorrow, and fit the bill of south of 15, east of 30. Beyond that, intensity is as always problematic, though a major hurricane is probable. While some people may think this may be on its way to being a fish storm, first, I would ask that those people consider that Bermuda could easily be in the crossroads later on. But history also suggests a Caribbean threat, and models are shifting west. Can’t say it enough, “the trend is your friend!” I predict Invest 92L will become a tropical depression on Monday, and Tropical Storm Katia on Tuesday. The storm will at first head mostly west or slightly north of, and then start to track more west-northwest Tuesday night or Wednesday. This west-northwesterly track will pretty much be the track Katia takes for most of the week, and the motion will also not be very fast. During this track, Katia will become a hurricane on Thursday near 40 degrees longitude. Before that day ends, Katia will become a C2 hurricane, and on Friday become a C3 hurricane as it nears 45 degrees longitude. Nearing 50 degrees longitude on Saturday, I predict Katia to become a C4 hurricane, and maintain that intensity through the weekend. The storm will then start turning more northwesterly through Labor Day, and by nightfall on Labor Day the storm will be a couple hundred miles northeast of the Leeward Islands. Confidence is 50%.

Now let’s head to the Gulf of Mexico. I predict the formation of Tropical Storm Lee on Saturday night or early Sunday morning in the Bay of Campeche. This storm will head northward towards Texas and intensify, but not be completely organized. This will at least prevent Lee from becoming a hurricane, but I predict Lee will be nearing landfall by Monday night along the Texas coast, with winds reaching as high as 60-70 mph. Welcome rains will begin falling in Texas as early as Sunday. Confidence is 50%.

And could something form at the end of the week? With only the NOGAPS seeing this right now I’m thinking no for now. I predict no other development besides Katia and Lee this upcoming week. Confidence is 50%.

Confidence all across the board is 50%. It’s going to be a very interesting upcoming week.

-Andrew92

[Meteorcane]

I think this forecast is a little more aggressive than some of your previous weeks and I think it will fare better.

[Andrew92]

I was actually cutting-edge close to putting potential Katia next to the Leeward Islands with the westward trend, but a post by another Met convinced me to think otherwise. However, it would DEFINITELY not surprise me.

This one took about two hours or so to write, and lots of studying the models and history.

-Andrew92

[LaBreeze]

Any chance that "Lee" would swing some moisture over to SW Louisiana and if so, when?

[Andrew92]

Oh, and I just saw the NHC upgraded the development from 70 to near 100 percent for Invest 92L. Definitely developing tomorrow, but not claiming a victory there until I see it happen.

-Andrew92

[Andrew92]

LaBreeze, to answer your question, I absolutely think potential Lee could bring moisture into SW Louisiana. I probably should have specified a location of landfall on the Texas coast, but thinking the Central to North Texas area for now. I think that would start probably late Sunday night or early next Monday. As for how long it lasts, I'm thinking it may last beyond next Monday, but I'm very hesitant to say how much longer. If that indeed happens, I'll bring it up next week.

-Andrew92

[LaBreeze]

LaBreeze, to answer your question, I absolutely think potential Lee could bring moisture into SW Louisiana. I probably should have specified a location of landfall on the Texas coast, but thinking the Central to North Texas area for now. I think that would start probably late Sunday night or early next Monday. As for how long it lasts, I'm thinking it may last beyond next Monday, but I'm very hesitant to say how much longer. If that indeed happens, I'll bring it up next week.

-Andrew92

Thank you so much for your reply

[Andrew92]

Long week over, time to evaluate.

Evaluating last week

After being in a rut for most of August, this week was an improvement overall. I correctly called for two storms to develop this week, Katia off the coast of Africa and Lee in the Gulf of Mexico. I also had a general feel for the tracks of both storms, and also did well on the intensity portion for Lee. I had a feel for Katia taking a general west-northwestward track, followed by a northwesterly track later in the period, and also nailed her becoming a C4 hurricane during the week. I also even did a good job with some early details, such as timing of development, timing of becoming a named storm, and only off by a few hours for becoming a hurricane. As for Lee, 60-70 mph was the range for that storm along a northerly track, both of which very much materialized, as the winds were 60 mph at the strongest. I also did well in seeing a possible development on Labor Day, but not calling for it as it hasn’t happened yet. True, the disturbance is there and poised to develop as Invest 95L, but the criteria there is to become a tropical depression at the minimum, not a mere Invest. Overall, there were plenty of positives to take from this past week.

However, this was still not a perfect prediction. First, Jose dissipated a little earlier than predicted, though not by much and that’s hardly a big deal given how weak and insignificant he was. Looking at everything else, for one thing, it is probably easy to figure out that the intensity of Katia was not well-predicted. This storm has had to battle stronger shear and dry air than predicted, and was only on the threshold of hurricane intensity or slightly below from the time it became a hurricane on Wednesday night all the way until Sunday. I had instead predicted a steady intensification into a C4 hurricane on Friday, and it just happened tonight. I also underestimated the forward speed Katia would take. I foresaw a slightly slower moving storm overall, gaining about 5 degrees of longitude per day and ending up a little northeast of the Leeward Islands. But Katia chugged at speeds of 20 mph or so, and is now about halfway between the Leeward Islands and Bermuda, a bit further west than I thought. For Lee, I predicted development during the weekend, and it instead happened Wednesday heading into Thursday, a good three days off. Lee’s general slow motion did save me a little for when it would approach the coast, but it did so further east than I thought. I predicted Lee would make its way into Texas, but it went into Louisiana instead, and did not bring the rains into Texas that I thought. Instead of approaching the coast, Lee is dissipating inland now. Timing apparently still remains a bit of an issue for these later-in-the-week storms, regardless of how well I did early on with Katia.

When meshing the pros with the cons of this past week, I did an overall very good job with Katia, and about average with Lee. Katia was a tricky storm to predict for intensity as most are anyway, but she seemed harder than normal. The track was very well-executed, just a tad slow. Lee was also a solid prediction with the intensity and general track, just a little further east and a few days off in terms of timing. No development late in the week off Africa, but at least seeing the potential there, was also a major plus. Overall, I give myself a B+ for Katia, a C+ for Lee, and an A for elsewhere. Lee was probably the most important, but Katia and Invest 95L do bring more of an average somewhere in the middle between those two and Lee, especially considering overall this past week was an improvement over much of August. With an average of A- for Katia and Invest 95L, and a C+ for Lee, I will give myself an overall grade of a B for this past week.

New short week coming up shortly.

-Andrew92