Major Highlights
NOAA REPORTS WORSENING DROUGHT IN NORTHWEST,
RECORD RAIN IN SOUTHWEST. WARM START TO JANUARY
GIVES WAY TO MUCH BELOW AVERAGE TEMPERATURES FOR EAST.
Drier than normal conditions prevailed across the Northwest in January, contrasting with a series of storms that produced record rainfall across the Southwest. Overall, temperature and precipitation were above average across the contiguous United States in January, according to scientists at the National Oceanic and Atmospheric Administration’s National Climatic Data Center in Asheville, N.C. NOAA is an agency of the U.S. Department of Commerce.
NOAA scientists report that 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 and 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 6th year of drought for portions of the northern Rockies and northern High Plains. Several consecutive drier-than-average months have led to abnormally low snowpack across the Northwest. Less than 25% 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% 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 and fall.
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% in December, to 18% in January. Despite the 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 a series of storms impacted the region and also affected the Midwest during late December and early January. Record rain totals occurred in Los Angeles and snow water content measured well in excess of 150% of average in much of the Sierra Nevada, southern Nevada and Utah at the end of January. While the pattern of wetter-than-average conditions in the Southwest and below normal precipitation for the Northwest is similar to what can be expected during an El Niño, conditions during the most recent December and January do not appear to be related to the ongoing weak El Niño. (see NOAA’s press release: http://www.noaanews.noaa.gov/stories2005/s2367.htm).
A feature of the Pacific climate known as 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-day period on record with 16.97 inches falling from December 27th-January 10th. Records for the city date back to 1877. Los Angeles had already surpassed its seasonal average rainfall by over 7 inches on January 10th. Over 20 inches of rain was recorded at some mountain stations in Santa Barbara, Ventura and LA Counties over just 5 days in January (6th-11th). The storm caused over 20 deaths (including 10 people in a mudslide in La Conchita, CA) and damage that will total tens of millions of dollars across the Southwest.
The average temperature for the contiguous United States for January (based on preliminary data) was 33.5°F (0.83°C), which was 2.5°F (1.4°C) above the 1895-2004 mean, and the 23rd warmest January on record. The mean temperature in 22 states was above average, with an additional two southwestern states (UT and NM) much warmer than the long-term mean. Only four states (ME, MA, RI and NY) were cooler than average. Temperatures during the first two weeks of the month were more than ten 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.
A major winter storm affected the Midwest and Northeast from January 21-24th. Nearly a foot of snow fell at Chicago O’Hare Airport and over two feet of snow fell across portions of eastern Massachusetts, with over a foot of accumulation occurring across a large area of southern New England. By January 27th, month-to-date snowfall at the Boston Logan International Airport totaled 43.1 inches, making January the snowiest month on record for the city.
Globe:
The average global temperature anomaly for combined land and ocean surfaces during January 2005 (based on preliminary data) was 1.17°F (0.65°C) above the 1880-2004 long-term mean. This was the 2nd warmest January since 1880 (the beginning of reliable instrumental records). Land surface temperatures were anomalously warm throughout Europe, Scandinavia and the United States, cooler-than-average conditions were widespread across Canada, as well as much of Asia. The January global ocean surface temperature was 2nd warmest on record.
El Niño:
Conditions associated with El Niño in the equatorial Pacific Ocean weakened in January, as ocean surface temperatures decreased across the basin. The monthly averaged ocean surface temperature in the Niño 3.4 region, which encompasses an area across the central equatorial Pacific basin, decreased to +0.68°C (+1.22°F) above normal during January. In the eastern equatorial Pacific region, ocean surface temperatures decreased to below average for the month. Despite these observed decreases, ocean temperatures remained slightly above the official NOAA threshold for a weak El Niño event across the central equatorial Pacific Ocean. Therefore, weak El Niño conditions persisted into January, but the 2004-2005 El Niño event likely began to diminish at the end of the month.
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