Warm Start Gives Way to Much-below Average Temperatures for East
Feb. 11, 2005 — Drier-than-normal conditions prevailed across the Northwest in January, while a series of storms brought record rainfall across the Southwest. Averaged across the U.S., both temperature and precipitation were above average for the month, according to scientists at the NOAA Climatic Data Center in Asheville, N.C.
January 2005 was the 23rd wettest January on record, when averaged across the contiguous United States. Wetter-than-average conditions stretched from California to the southern Plains, north to the upper Midwest and New England. Precipitation was below average in the Southeast and unusual dryness continued in the Northwest, contributing to the sixth year of drought for portions of the northern Rockies and northern High Plains.
Consecutive drier-than-average months have led to abnormally low snowpack across the Northwest. Less than 25 percent of seasonal average snow water content was present at the beginning of February for parts of western Washington State, with widespread measurements of less than 75 percent of average snow water content for the broader Pacific Northwest and into the northern Rockies. (A below average snow season results in less spring melt and lower reservoir levels for the spring and summer.)
The percentage of the West in moderate-to-extreme drought (based on a widely used measure of drought, the Palmer Drought Index) increased from 7 percent in December to 18 percent in January.
Despite dryness in the Northwest, the meteorological drought in the Southwest has been essentially eliminated by a wet fall and early winter. The recent wet pattern intensified for the Southwest, as storms impacted the region and the Midwest during late December and early January. Record rain totals occurred in Los Angeles and snow water content exceeded 150 percent of average in much of the Sierra Nevada, southern Nevada and Utah at the end of January.
A feature of the Pacific climate, called the "Pineapple Express," brought moisture-laden air directly from the Pacific sub-tropics and fueled the storms moving into southern California at the end of December and into January. As a result, Los Angeles had its wettest 15-days between Dec. 27 - Jan. 10 with 16.97 inches rainfall.
Los Angeles had surpassed its seasonal average rainfall by more than 7 inches by January 10. More than 20 inches of rain was recorded at some mountain stations in Santa Barbara, Ventura and Los Angeles Counties over just five days.
The average temperature for the contiguous United States for January (based on preliminary data) was 33.5 degrees F (0.83 degrees C), which was 2.5 degrees F (1.4 degrees C) above the 1895-2004 mean, and the 23rd warmest January on record. The mean temperature in 22 states was above average, with two additional southwestern states (Utah and New Mexico) much warmer than the long-term mean.
Four states (Maine, Massachusetts, Rhode Island and New York) were cooler than average. Temperatures during the first two weeks of the month were more than 10 degrees below average in parts of the northern Plains, while the mid-Atlantic and Southeast were as much as 15 degrees above average. A reversal in the temperature pattern occurred abruptly mid-month causing colder conditions in the East and above average warmth across much of the West.
