Very Cold Start To 2011

View of the snow-covered Santa Rita Mountains south of Tucson - photo taken yesterday morning, New Years Day, looking west from the foothills northwest of Sonoita.
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Another morning with low temperature in the teens - 17F. Last three mornings have seen low temperatures here at the house of 18F, 17F, and 17F. There have been some impacts and I'll show these in a later post.
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Regarding the Flagstaff sounding shown in the post below:

David Blanchard has left a new comment on your post "Last Evening's Flagstaff Sounding - Worth A Look":

I've tabulated the 10 coldest 500 mb temps at KFGZ for the period 1995-2010. It will take a bit more work to get the data for KINW.
PRES HGHT TEMP DWPT DRCT SPED HH DD MMM YYYY

500   5410     -329   -409       300 33        00 1 MAR 2007

500   5414     -331   -357       253 8          00 7 DEC 1998

500   5450     -331   -431       290 27        12  27 DEC 2003

500   5370     -335   -362       255 41        12  12 MAR 2006

500   5450     -335   -445       335 23        12  29 NOV 2004

500   5472     -336   -439       311 33        12  23 JAN 1996

500   5300     -337   -497       275 57        12  31 DEC 2010

500   5360     -349   -449       300 16        12  27 DEC 2007

500   5400      -361 -403        285 19        00  27 DEC 2008

500   5250      -375 -435        285 33        00  31 DEC 2010
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Thanks David! The 31st was the coldest since the UA-site moved west to Flagstaff. The very low 500 mb height is also very impressive. The last week in December obviously favors very cold intrusions into the Southwest.