MONTHLY WEATHER SUMMARY
By Bill Mork
California State Climatologist, California Department of Water Resources
February 2005

Read the full California Climate Watch newsletter here: Word Format or PDF format

The combination of weak El Nino conditions and persistent winter season upper air features contributed to the continuation of a low latitude storm track and high latitude ridging on the West Coast in February 2005. This perpetuated the seasonal trends for much above normal precipitation in Southern California and much below normal precipitation in the Pacific Northwest with developing drought conditions in that area as well as the Northern Rockies. Upper air conditions also dictated the monthly average temperatures which ranged from a little above normal in Northern California to below normal in Southern California. A couple of the cooler locations in the Southland and Southeast California Deserts include Sandberg with an average temperature of 41.7 degrees, 2.8 degrees below normal, and Palm Springs with an average temperature of 58.7 degrees, 2.3 degrees below normal. There were no freezing temperatures at lower elevations of the Central Valley, Bay Area, Central Coast, South Coast, or Southeast Deserts except for a low of 32 degrees at Madera on February 1.

The previous seasonal trends of dry north/wet south were exacerbated with the far northern counties having a really dry February with similar conditions in the Klamath River basin of southern Oregon. The real dusters were Yreka with 0.52 inches, 23 percent of average, and Crescent City with 2.35 inches, 26 percent of normal. In contrast was Southern California and the Southeast California Deserts where monthly precipitation was mostly 2 to 3 times normal, but with some locations 4 to 5 times normal in February. The monthly total of 2.40 inches at Needles was almost 4 times normal and fell on 10 rain days compared to a normal of 3 rain days in February. Two of the largest multiples were at Blythe with a monthly total of 2.87 inches, 522 percent of the monthly normal, and at Thermal Airport with 2.66 inches, 422 percent of normal.

The February total of 11.02 inches in downtown Los Angeles was the sixth wettest February since records began in 1877. The seasonal total of 33.87 inches at the end of February represents the third wettest season on record in Los Angeles, only outdone by 34.84 inches in 1889 - 90 and 38.18 inches in 1883 - 84. To summarize, Los Angeles is in the midst of its wettest winter season in 115 years, exceeding anyone's memory that we know of. The seasonal rainfall total at San Diego Lindbergh Field had reached 19.64 inches by the end of the month. This has already become the third wettest San Diego season on record, beat out only by 24.74 inches in 1940 - 41 and 25.97 inches in 1883 - 84. This is the first season since records began in 1850 at San Diego that 4 inches or more of rain has fallen in 4 separate months in a single season. Those monthly totals include 4.98 inches in October 2004, 4.01 inches in December 2004, 4.49 inches in January 2005, and 5.83 inches in February 2005, 288 percent of the monthly normal.

Once again this winter, the Southland was deluged with an excessive period of precipitation, February 17 - 23. Impact totals include 9 people dead, with at least 2 deaths from mud and rockslides and a civil engineer who was swept by rushing water into a large sinkhole. Property damage was in the millions, including the much-chronicled collapse of the runway at the Santa Paula Airport into the rain-swollen Santa Clara River. With lower snow levels than earlier months this winter, snowfall measured 8 to 10 feet in the mountains above Los Angeles. This wet pattern was set up by a "Rex Block", occurring as a blocking high pressure area set up off the British Columbia coast while an upper level low pressure area parked off the California Central Coast near 130W. Numerous short waves and jet stream energy combined to bring pulses of heavy rain and snow into the Southland during this period with excellent orographic precipitation release in the transverse mountain ranges of Southern California. Some key storm totals include 22.40 inches at Opids Camp (Los Angeles County), 13.78 inches at Nordhoff Ridge (Ventura County), 11.85 inches at San Marcos Pass (Santa Barbara County), and 8.24 inches at Palomar Mountain in San Diego County.

For another outstanding job by Mike Ekern and Dan Kozlowski (NWS/California - Nevada River Forecast Center) in summarizing a key storm event this winter, check out the following link: http://www.wrh.noaa.gov/cnrfc/feb2005storms.php

Page last updated 3/11/05.