Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Aug 16 2007 04:43 AM |
Areas of Concern - The 'E' 'D' Storms
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Tropical Storm Erin just off the southeast Texas coast is firing up new convection to the northeast of the center that could force some intensification just prior to landfall at sunrise on Thursday near Aransas Pass. Erin will be primarily a rain event for southern Texas.
Soon to be Hurricane Dean moving west in the central tropical Atlantic toward the central Caribbean islands. Dean is currently a small 'Charley'-like storm and Guadeloupe appears to be in the direct line of fire with impacts also likely on St Lucia and Martinique. With a strong western extention of the Atlantic ridge holding firm, Dean should continue on a generally west to west northwest track across the Caribbean Sea and into the southern Gulf of Mexico. Probable impact on the northern Yucatan as a Cat III or Cat IV hurricane.
Normally long range forecasts can be problematic, but so far, this one seems to be behaving. The trough in the Bahamas, actually more of a developing mid to upper level cutoff low, is not expected to be strong enough to alter Dean's forecast path. The circulation around the cutoff low could actually help to maintain the southern portion of the western extention of the mid Atlantic ridge over Florida - and keep Dean on his west northwest track.
Elsewhere, the new wave exiting western Africa is worth an occasional glance. If anything develops from it by early next week, the track will probably be a little further to the north.
Cheers,
ED
| madmumbler |
| (Storm Tracker) |
| Sun Aug 19 2007 03:48 PM |
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Re: Areas of Concern - The 'E' 'D' Storms
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I hope this is the right forum to post this.
Is it unusual for Erin's remnants to still show such a clearly defined signature this far inland? They were showing her on TWC this morning as she's moving into OK, and it still looks like a "tropical system" to me. (I know it's not, but it looks like one.)
Why is this? Has it not hit a lot of hilly terrain to really break it apart, or is it due to not having a lot of atmospheric interference, or what?
Thanks,
| Clark |
| (Meteorologist) |
| Sun Aug 19 2007 05:42 PM |
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Re: Areas of Concern - The 'E' 'D' Storms
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Regarding Erin, yes, it is unusual but not necessarily unprecedented. Most of the other cases involve interaction with a trough and occur much further to the east, though there are a few Texas cases as well. What happened last night was probably somewhat similar to intense convective systems that fire in the central Plains during the warm season, with an intense low level jet stream supporting convection on the east side of the storm. The remnant circulation center provided the focusing mechanism for that convection and it took on the appearance of an intense overland tropical cyclone once again.
| Thunderbird12 |
| (Meteorologist) |
| Sun Aug 19 2007 09:42 PM |
| Attachment |
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Re: Erin
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Check out the attachment for a cool image of Erin (briefly) reborn early this morning. The attached image comes from the Norman NWS website.
I have never seen a remnant tropical system rejuvenate over land quite like Erin did last night, though I paid more attention to it than most because it happened in my backyard. It wasn't really like a typical MCS that we get around here... there was no cold pool or outflow and... well, MCSs don't have eyes either (see attached image). Erin looked better last night on radar than it ever did as a tropical storm... in fact it was probably more of a tropical storm last night (in terms of wind intensity and structure) than it ever was before (which isn't saying much).
The eye was a legitimate feature... there was intense rotation around it and it lasted for several hours, and it was the center of a vertically deep low pressure system that extended down to the surface. Just north of the eye feature, there is a Oklahoma mesonet site that reported sustained winds of 40+ mph with gusts over 60+ mph for over 3 consecutive hours (with some gusts over 70 mph) as the storm moved slowly past, from about 1-4 am CDT this morning. The winds caused extensive tree and structural damage in that area because of the duration of the event. There were numerous other strong winds reported around the path of the low as well. It also dumped 6-12 inches of rain over a large area in about a 6-hour period, resulting in catastrophic flooding in parts of the state.
The local meteorologists (both TV and NWS) were astonished by what happened last night with Erin over Oklahoma. They have seen a lot, including plenty of remnant tropical systems over the years, but nothing remotely like this. Obviously, it wasn't a purely tropical system, but it was a very close relative. As Clark mentioned, the nocturnal LLJ probably helped to crank it up, but the convection was apparently intense enough to temporarily invigorate the remnant circulation of Erin, which was still a tropical low pressure system.
Another amazing aspect of this was that the 00Z NAM from yesterday evening actually forecast something like this to happen, before anything really cranked up. It developed a small, intense low pressure system and generated outrageous QPFs (max over 10 inches) over central OK. I initially dismissed the model run because it looked like a convective feedback problem that pops up in the models sometimes, but convective feedback is something that actually happens in the atmosphere sometimes, too.
| madmumbler |
| (Storm Tracker) |
| Sun Aug 19 2007 10:21 PM |
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Re: Erin
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In other words, it wasn't just my imagination that it looked so bad? *LOL*
Man, I feel bad for y'all out there. I saw some video feeds of the flooding and that's just mind boggling. I'm just not used to that and haven't experienced anything like that. The only flooding I've experienced first hand was storm-surge related because I lived (and still do, but in a different place) so close to the Gulf.