Tropical Storm Chris update 020500L plus a pair of tidbits.

August 2, 2006

As noted in the update to my previous post,  Chris’ maximum sustained winds did not increase during the time between advisory packages. He is still a 60 mph tropical storm.  However, his overall appearance on satellite has improved during that time-frame, and it would not be surprising if recon were to find slightly stronger winds before departing from the storm later this morning.

Those are the observations made in the first paragraph of the forecast discussion. Uncontroversial stuff. The second paragraph does bother me, however. The forecaster read the models differently than I did, and stated that most of the models now hold on to Chris as a tropical cyclone (instead of killing it off). Goes on to say that there has been a northward shift in the models, and suspects that the trend may continue.

My contention to that is that the UKMET and GFS models are still killing off the storm, and those two models are half of the GUNS consensus (an average of four models that tends to yield one of the most accurate forecasts overall).  There are still too many models underdeveloping/underrepresenting the storm. It seems to me that this is causing the models to inappropriately guide Chris along a lower level steering current than is appropriate, which owing due differences in the steering currents at the low through high levels introduces a northern bias.  While I wouldn’t bet large on the GFDL forecast (which is the southern outlier), I wouldn’t toss it either, which is essentially what the forecaster did.

The result of that thinking is that I don’t belive that there will be a further northward trend in the models, and that the nudge northward in the forecast track was the wrong thing to do. Perhaps I’ve become too invested in my thinking and need to take a fresh look at things, but that’s the way I see it at the moment. If the forecaster is right, then this is definitely a concern for peninsular south Florida. My thinking is that its more of a concern for the Keys than anyone else in the state.

Recon just found 65 knot flight level winds, a new maximum observed in this storm. The difference is slight of course, it just puts Chris closer to a “true” 60 mph rather than a rounded up 60. It would take 70 knots at flight level to justify a bump in the intensity posted in the advisories.  I’m thinking that Chris will make hurricane strength by the 5 PM advisory, which is roughly a day ahead of the NHC forecast, but is a possiblity acknowledged in the advisory.

Onto the tidbits…

  • I’ve never written much about the seasonal forecasts put out by Colorado State and others, because I feel that they aren’t particular useful to the average individual. I had a vague feeling that I couldn’t quite articulate, that what is a “inactive” season isn’t inactive from a person’s standpoint if they still got affected by a storm. Would have if I could have put it as nicely as NHC forecast specialist Richard Pasch did in a recent Palm Beach Post article :

“An active year is the year when you get hit.”

  • In my post on the formation of Tropical Depression Three, I expressed my belief that it was a harbinger of the turning point in the season. Indeed, it does look like the pace is quickening as the GFS, Canadian, and UKMET models are all forecasting development of a tropical wave into a tropical storm as it travels from the coast of Africa past the Cape Verde islands during the next five days. I might not think too much of it if it were just the GFS and Canadian models, but the inclusion of the UKMET adds a fair amount of credibility to the forecast.

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