Winter Storm and Frost and Freeze in California, November 7 to 12, 2010

November began with a strengthening upper-level ridge building into California. This ridge, combined with a surface high pressure over the Pacific Northwest and a surface trough along the southern California coast for an offshore flow, brought a strong warming trend for the first several days of the month. Temperatures rose to a couple of degrees above normal on the 1st, and a few degrees warmer the next day. By November 3rd, an upper-level trough was digging into the eastern Pacific, while another trough deepened over the Ohio Valley. The ridge over California was caught between the troughs and continued to amplify over California, resulting in very|strong warming on the 3rd and 4th. High temperatures across the central and southern San Joaquin Valley reached the lower to mid 80s both days; the normal highs were in the upper 60s to around 70.|The ridge over the central and southern San Joaquin Valley also resulted in clear skies and light winds. As a result, patchy dense fog formed in the Merced area shortly before surrise each morning. These fog patches were short-lived, typically burning off after a couple of hours.|The east-Pacific trough began moving toward the coast on November 5th. Ahead of the trough, the ridge amplified further, and combined with a southeasterly downslope flow, pushed temperatures across the central California interior to well above normal. Fresno reached a high of 90 degrees on the 5th, the first time on record that the high reached 90 in November. Bakersfield had a high of 94 degrees, just one degree shy of the record high for the month (95 on November 8th, 1918, and November 3rd, 1921).|Temperatures fell the next day as the trough moved onshore. Fresno only had a high of 75 degrees, 15 degrees cooler than the day before. Bakersfield was 10 degrees warmer, but the high of 85 at Meadows Field was down 9 degrees from the 5th. The trough moved into central California on November 7th, bringing colder air and moderate precipitation. Rainfall amounts for the central and southern San Joaquin Valley mostly ranged from to inch. In the mountains and foothills, up to 1.86 inch of rain was recorded, and up to 16 inches of snow fell in the high|country of the southern Sierra Nevada. Gusty winds accompanied the cold front as it moved through the southeastern Kern County desert on the 8th, with gusts of 45-55 mph occurring during the late morning and afternoon.|Temperatures fell to several degrees below normal on November 7th as cold air filled the San Joaquin Valley. Central and southern San Joaquin Valley high temperatures were in the upper 50s and 60s on the 7th, and in the lower to mid 60s the next day as the cold air remained trapped by the mountains surrounding the San Joaquin Valley.|A weak upper-level short-wave moved into California on November 9th, bringing another push of cold air into the central and southern San Joaquin Valley. As a result, the 9th was the coldest day of the period, with central and south Valley highs only in the upper 50s to mid 60s, The short-wave brushed the northern edge of the central California interior during the night of the 9th-10th, bringing light precipitation as far south as Fresno County.|The cold air pooled over the San Joaquin Valley slowly mixed out over the next couple of days, allowing temperatures to warm a few degrees. Valley highs on November 12th were in the mid 60s to the lower 70s, although lows were in the mid 30s to lower 40s, with patchy frost in the coldest outlying areas around sunrise. Temperatures were even colder in the Kern County deserts, where the coldest spots saw their first hard freeze of the season. An automated station in Rosamond recorded a low of 23 degrees, and Edwards AFB North Base had a low of 26.