Winter Weather Discussion 2008-2-1

Winter Weather Discussion for January 21 – 23, 2008.
Valid: 01/17/2008.

Highlights:

– Freezing rain is possible Monday and Tuesday next week with the most likely area the eastern 2/3rds of Oklahoma.

– Snow is possible on Wednesday across parts of the state.

Discussion:

Review of 12z GEFS and 18z GFS runs indicate potential for winter weather across Oklahoma Monday through Wednesday. Details are quite muddy this evening and expect this to be the case for a few more model runs.

Midlevel pattern has become very amplified across the western Hemisphere with a longwave ridge located just off the Pacific coast and a closed low in Canada. Models agree that a shortwave trof will dive due south on the downstream side of the ridge and take up residence over the southwest U.S. by late Monday. While prior cold fronts have put a dent in Gulf moisture, models indicate that at least 50F dewpoints are available when this system approaches. Moisture return is expected to begin on Monday as the 850mb low develops in the southwest U.S. With 850mb dewpoints of 10C in Texas, there is plenty of moisture available in Texas.

AFDOUN was a great read, especially pointing out the differing model solutions. The GFS/NAM/GEFS members have differing opinions on the Arctic cold front expected late Sunday into Monday. I do agree with OUN that the pattern favors a shallow Arctic airmass which should dive into the region. As it encounters southwest flow aloft and increasing WAA, it should stall. Models usually have a very poor handle on these situations and being four days out makes it much worse. One big concern on this matter is the GFS QPF fields. Current fields have 0.20 liquid equivalent Monday into Tuesday, this would most likely be ice. Concern relates to its frontal position way in Texas cutting off moisture. Should this not be the case more moisture would likely be available with a corresponding increase in QPF amounts.

For now this is a setup to watch. Not worried about a big event right now, but hey the Dec 9th storm was caused by a northern stream system not the expected southern stream low. It doesn't take much.

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About Putnam Reiter

Putnam has been storm chasing since 1990 and is a co-founder of Hook-Echo.com. For his day job, Putnam works in emergency management for information technology.
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