Monday, July 11, 2011

Monday July 11th - Improved Situation For Storms (NOT)

Edited to add: Yesterday did not evolve as I thought it would. I felt that the subtrioical wave would spread light showers and embedded thunderstorms over southeast Arizona. Wave apparently came right over southeastern Arizona, but storms and rain stayed mostly off to east and north. Only 29 of 93 ALERT gauges measured rain (~ 30%), and these tended to be the high elevation stations. Third day in a row with no rainfall down in the Tucson metro area - except light spinkles. Ugh - so it goes, with alot of high POPs down the tubes.


The morning Tucson sounding (above) appears to have a bit more CAPE than did yesterday's. Steering level winds from south-southeast have increased in speed. Anvil-level flow could be anywhere from south-southeast to southwest. PW is up a bit (note that sounding appears a tad too moist) and Yuma has had a weak surge in low-level moisture during the night. First push of the Pacific trough at 500 mb appears to be over the Mojave, and Yuma has already experienced drying at 850 mb. While the Pacific trough will be producing some degree of Arizona dryout this week, the interesting feature today is to our south.


A visible satellite iamge for 1430 UTC this morning is shown above. There is a distinct subtropical wave indicated by the cloud pattern, near 30 N and 110 W. This feature, as well as the large cloud mass ahead of it, is advancing to the north-northwest. So, even though there is abundant cloud cover around, the subtropical wave will move into Arizona ahead of the Pacific trough, giving parts of southeastern Arizona a better chance of rainfall this afternoon and tonight. The flow aloft is not good for here at the house - unless a nocturnal MCS develops. But, it looks like an interesting 24-hours before the Pacific trough pushes the moisture plume eastward into New Mexico.
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Note - Mike Leuthold commented yesterday that the Mexican soundings (except ay Guaymas) are being taken but are not appearing on the skew-T pages - check for example WY standard level plots for North America. So, I was wrong the last few days about the models having no data over much of Mexico - we just have the Sonoran data void to our south.

Note - I will only be able to make some intermittent posts during the next several weeks.

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