String of storms makes for wet February in Los Alamos, White Rock

A series of storms pushing through the southwestern United States dropped abundant precipitation on Los Alamos and White Rock in February contributing to a wet start for 2005.

It also was warm, due in part to a blocking pattern that made the entire southwest warm, said Jeremy Rishel, a Lab meteorologist in Meteorology and Air Quality (ENV-MAQ).

Rishel said Los Alamos recorded 2.11 inches of precipitation last month, far greater than the normal precipitation of .75 inches. Likewise in White Rock, 1.69 inches of precipitation was recorded, or 213 percent of the normal (.54 inches) for February.

Rishel said total precipitation through the end of February in Los Alamos is the fourth highest since record-keeping began in 1911 at 4.74 inches. And in White Rock, the 3.36 inches through February is the wettest since record-keeping began in 1965.

"The abundant moisture can be attributed in part to what meteorologists call a 'blocking pattern' whereby a high pressure system cutoff from the main flow blocks the normal west-to-east progression of storm systems--much like a stone in a stream that impedes the flow and diverts water around it," said Rishel. "When blocking patterns form, they can cause anomalous weather because they characteristically tend to persist for quite a period of time, anywhere from a week out to a month," he said.

Rishel said this blocking pattern contributed to the persistent rains in southern California, and also drier-than-normal conditions in the Pacific northwest. He noted that nearly 14 inches of precipitation was recorded in January and February in Los Angeles, almost double the normal, while in Portland, Ore., 3.24 inches of precipitation fell in the first two months of 2005, only one-third of the normal.

In February, 12.7 inches of snowfall was recorded in Los Alamos; the normal snowfall is 9 inches for the month, said Rishel. This season, 48.1 inches of snowfall has been recorded at the Technical Area 6 measuring station. Rishel said the total is 6.5 inches greater than the normal snowfall through February (41.6 inches).

Rishel said the mean maximum temperature in February in Los Alamos was 42 degrees Fahrenheit, or 2 Fahrenheit below normal. The mean and mean minimum temperature, however, were above normal.

In White Rock, the mean maximum temperature of 46 F in February was 2 F below normal, but the mean and mean minimum temperatures were above normal.

Rishel said the National Center for Environmental Prediction outlook for March calls for above normal precipitation and temperatures, with the trend possibly extending into early spring.

--Steve Sandoval

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