Question about ULL in Gulf
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- frederic79
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Question about ULL in Gulf
I have been watching the approaching cold front on WV loops since yesterday. The front is clearly advancing eastward, however the last few hours seem to show some slowing. What, if any, effect does the ULL in the NW Gulf have on an approaching trough? It seems to be moving slowly north or northwest. The high pressure centered off the east coast is still centered near 77 west longitude. We could use some cool fall weather here but I'm beginning to wonder if the front gets this far south? Comments welcome.
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- KFDM Meteorologist
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- KFDM Meteorologist
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- Location: Upper Texas Coast/Orange County
- KFDM Meteorologist
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Just as a note... I mentioned this last night, but it's quite important, and could save someone confusion down the road... You cannot see surface fronts on water vapor imagery! Water vapor imagery displays water vapor content in the mid- and upper-levels; many fronts are best seen and defined well below 700mb (i.e. the low-levels). The best way to track a cold front is by looking at surface observations. You can get yourself very confused very quickly if you try to associated a feature on water vapor to what is primarily a low-level feature (yes, there are features like cold fronts aloft, but we won't go there). Sometimes, processes associated with fronts are reflected in water vapor imagery (e.g. perhaps some mid-level subsidence associated with strong cold-air advection behind the front, etc), but that is not a dependable way of identify frontal zones (e.g. you could very well have a front at the surface with almost no discernable "feature" on water vapor). In the cases of very deep frontal zones, where a strong moisture gradient exists, you also need to account for frontal zone tilting, so there could be significant displacement anyway.
CLICK HERE for a little more detailed explanation. I left out all discussion on semi-geostrophic theory and it's implications in flow near fronts.
CLICK HERE for a little more detailed explanation. I left out all discussion on semi-geostrophic theory and it's implications in flow near fronts.

Last edited by WxGuy1 on Tue Aug 29, 2006 3:37 pm, edited 1 time in total.
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- KFDM Meteorologist
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- frederic79
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