2012 water year ends with another dry month

A few wet days in September weren’t enough to make up the year-long moisture deficit.

September precipitation below average at Breckenridge and Dillon; temps slightly above average

By Bob Berwyn

FRISCO — September precipitation dipped back down below average in Summit County, with Breckenridge weather watcher Rick Bly reporting a total of 1.07 inches for the month, compared to the average 1.47 inches.

The weather year also ends Sept. 30, and in Breckenridge — perhaps surprisingly, given all the drought talk — precipitation ended up at 18.56 inches of rain and melted snow combined, just about 89 percent of average (20.67 inches).

Meteorologists use and Oct. 1 to Sept. 30 year because it matches up better with seasonal hydrological cycles than the calendar year.

Big rains like in July helped Breckenridge catch up to the annual average. Winter winds and warm temps in late spring and early summer were a big factor in the drought conditions, along with generally below average snowfall during the late winter and spring.

Precipitation was above average at Bly’s weather station for five months of the year: October, January, February, July and August, but that couldn’t make up for the deficits in the rest of the year, especially March and April, which usually deliver copious moisture. Total snowfall for the year was 164.8 inches, compared to the average 199,5 inches.

October is the driest month of the year in Summit County, average just 1.27 inches of precipitation, but it wouldn’t be unusual to get a blast of snow. Average snowfall for the month is 12.3 inches, and in more than 100 years of records, there has only been one October without snow — and that was not so long ago, in 2000, which ended being an average snowfall year after the dry start. Last year, October delivered 9 inches of snow.

The wettest October on record was in 1892, with 4.1 inches, the driest was in 1952, with 0.05 inches, and the snowiest October on record was in 1969, with 64.5 inches.

And since everything seems to be centered around the presidential election right now, Bly looked back at the 16 elections since 1948 to see if there are any weather trends that might influence votes.

It turns out that, in the winters following a Democratic presidential win (seven times), three were above average and four were below average.

When Republican candidates won the presidency (nine times), six of the subsequent winters were above average, and three were below average.

Precipitation for the month was also below average in Dillon, where Denver Water officials measure rainfall, snow and temperatures for the National Weather Service. According to the monthly report, total precipitation was just0.78 inches, compared to the average 1.36 inches, based on records dating back to 1909, although the location of the station changed when the dam was built.

Dillon temperatures for September were just slightly above average, with the average maximum temperature at 66.9 degrees, as compared to the historic average of 66.2 degrees.

The average daily minimum was 29.5 degrees, almost 1 degree above the long-term average of 28.7 degrees. A total of 16 days reached 70 degrees or warmer, with the high for the month reaching 75 degrees on Sept. 10.

Temps dropped below freezing 23 days in September, with the coolest reading on Sept. 14, at 23 degrees.

The weather story was a little different on the other side of the Continental Divide, where Denver reported its fifth-wettest September on record, including two daily maximum precipitation records, with 0.95 inches on Sept. 12 (old record, 0.91 inches, 1875, and 1.41 inches on Sept. 25 (old record, 0.71 inches, 1908).

For the month, Denver tallied 2.95 inches, which is 1.99 inches above the average of 0.96 inches. The city’s wettest September on record was in 1961, with 4.67 inches of precipitation.

Denver’s monthly average temperatures was 66.3 degrees, which is 2.9 degrees above normal, but not in the top 10 warmest. The warmest day of the month was Sept. 1, at 95 degrees. Altogether, temps climbed into the 90 seven times, but no temperature records were set.

According to the National Weather Service, September 2012 marked the 12 consecutive September without snow. The last time there were this many consecutive years with no September snow was nearly 100 years ago (1914-1926).


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