March in the West
March was drier than normal for much of the West, especially northern California, northern Nevada, Oregon, and eastern New Mexico. The northern tier of the West was slightly cooler than normal while many locations in the southern Great Basin and Desert Southwest saw March average temperatures among the highest on record.
High pressure aloft over California kept storm tracks to the north and temperatures around 5 F (2.8 C) above normal in the southern Great Basin and Desert Southwest. Las Vegas, Nevada recorded its 2nd highest average March temperature at 64.8 F (18.2 C) as well as its 2nd highest average minimum March temperature at 54.2 F (12.3 C). Records at Las Vegas began in 1937. Death Valley, California hit 100 F (37.8 C) on March 17, tying the same date in 2007 as the earliest triple-digit temperature since records began in 1961. Yuma, Arizona logged its 2nd highest March average minimum temperature on a 137-year record with an average 56.6 F (13.7 C). The average March temperature at Yuma was 70.6 F (21.4 C), and tied for the 7th warmest on record. In California’s Central Valley, Fresno recorded its 3rd warmest March on record at an average 62.1 F (16.7 C). Further north, Reno, Nevada recorded an average 49.4 F (9.7 C), the 3rd warmest March since records began in 1888. Cooler than normal weather was observed this month in the inland Northwest. In northeastern Montana, Glasgow recorded a March average of 24.3 F (-4.3 C), 7.4 F (4.1 C) below the March normal.
After a dry January and February, sparse precipitation continued in March over much of the West. In the central Sierra, Tahoe City, California recorded its driest January-February-March in a 103-year record at 2.68 in (68 mm), only 16% of the normal 16.3 in (414 mm). Elsewhere in northern California, Ukiah also recorded its driest start to the year at 4.05 in (103 mm), 15.02 in (382 mm) below normal. Only 6.99 in (178 mm) of precipitation fell in downtown Portland, Oregon since the first of the year. This was the driest such period in a 123-year record and 47% of normal. Many other locations throughout Oregon, Nevada, and California recorded one of their 10 lowest January-February-March precipitation totals on record. A winter storm on the 8th and 9th brought precipitation to the Southwest (especially CA) and snow accumulations up to 24 in (610 mm) in mountainous areas. This was the only precipitation of the month for much of this region, but enough to keep many locations above 50% of normal. Colorado’s Front Range received beneficial precipitation this month as well. Boulder recorded its driest March on record in 2012, while March 2013 fell just short of one of the top-10 snowiest on record at 23.5 in (59.7 cm).
The end of March is typically the peak snowpack for many locations in the West and an important date for anticipation of springtime runoff. Snow water content in the northern Cascades and northern Rockies was near normal to slightly above normal at month’s end. To the south, snow water content in the Sierra Nevada, Utah’s Wasatch and Uinta ranges, the southern Rockies, and Arizona’s Mogollon Rim region stood at less than 75% or less of normal. This is the second winter in a row these areas have recorded below normal snow water equivalent in their snowpack at the end of March, raising concerns about water resources. As solar isolation increases in the Arctic with the changing of seasons, sea ice extent has begun to decline and locations along Alaska’s North Slope are displaying above normal temperatures for March after being cooler than normal during December and January. Barrow reported an average -7.4 F (-21.9 C) for March, 5.3 F (2.9 C) over normal. A dramatic and rapid breakup of the thin pack ice of the Beaufort Sea north of Alaska took place over February and March. Temperatures elsewhere in the state were generally several degrees below normal. Near-normal precipitation fell throughout southern Alaska, though portions of the Interior and Southeast regions were below normal for the month. Further south, cool and stormy weather dominated in Hawaii. After 12 days of sub-80 F (26.7 C) highs, Honolulu hit 81 F (27.2 C) on March 22. This was the longest period of sub-80 F (26.7 C) highs since March 2-14, 2012.
Significant Events for March 2013
March (all month): Missoula, Montana temperatures: The airport at Missoula, Montana has not seen a sub-0 F (-17.8 C) temperature reading since February 25, 2011. This is now the second longest such period on record. If their temperatures stay above 0 F (-17.8 C) through the end of October 2013, this would be the longest such period on record. It is highly likely that temperatures will not dip below 0 F (-17.8 C) between now and October as they have never done so previously in the station’s 65-year record.
March (all month): Drought continues in the West: According to the U.S. Drought Monitor, severe drought conditions continued for much of the West this month with over 80% of the West at least abnormally dry. Severe to exceptional drought continued for New Mexico, Colorado, and Wyoming and the region of severe drought expanded in northern Nevada. Abnormally dry conditions spread through eastern Oregon and southwestern Montana as well. Some drought relief was seen this month in northeastern Colorado.