#443 Postby wxman57 » Tue Jul 25, 2006 2:52 pm
Swirls, swirls everywhere! That weak swirl which was southwest of Brownsville in northern Mexico this morning has raced off to the NNW and is dissipating northwest of Brownsville this afternoon. I've been monitoring the offshore obs very closely today, and there is definitely no closed LLC over the water. Pressures have actually risen a bit out there.
Everyone seems to see a swirl (on radar) out over the water. Sometimes radar loops can be deceiving. Echoes forming/dissipating, and the movement of outflow boundaries can give the appearance of a circulation. JB said it was SE of BRO this morning, we thought we could see something NE of BRO. It's obvious that if there are any swirls out there, they're pretty weak.
And remember, radar is tilted up at an angle of at least 1/2 degree. That, combined with the curvature of the earth means that for each mile away from the source, the beam is higher above the ground (water). So the swirl you'lre looking at on radar could be well above the surface (from 5-10 thousand feet up to 20-30 thousand feet up). I did notice that the swirl we saw from CRP radar (farther from radar beam) was more pronounced than the same swirl from BRO (closer to radar), indicating it was fairly high (above 10,000 ft).
While is isn't impossible for a weak closed LLC to form over the water before the whole mess moves ashore tonight/tomorrow, the main threat from this system will be rain, not wind. Could be 5, 10, or over 15 inches in some parts of the mid to upper TX coast tomorrow as we get into the north-south oriented bands rather than today's east-west bands.
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