September weather had sharp divide from warm to cool

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WALLA WALLA — September was wet, windy, surprisingly warm, then cool.

Although it may seem a little hard to remember now, last month delivered its share of hot days before summer said goodbye.

The high mark was 98 degrees on Sept. 15, just a week before autumn officially began on Sept. 22. Overall the average temperature was 68.2 degrees, just about three degrees above normal for the month.

Along with Sept. 15th, there were six other days when the temperature exceeded 90 degrees. Daytime highs averaged 78.8 degrees, which was just about one degree above normal while nighttime lows averaged 57.5 degrees, which was just about 5 degrees above normal.

Now about the wet and windy part.

A violent storm packing high winds, lightning and lashing rain hit the area on Sept. 5, blowing down trees, limbs and power lines. Along with blacking out hundreds of people, the storm also knocked out Walla Walla Regional Airport’s automated weather station, which left the official data for that day missing.

Unofficially, the station recorded a peak gust of 61 mph before it went offline and a weather spotter in Milton-Freewater recorded a gust of 65 mph. According to Dennis Hull of the National Weather Service in Pendleton, meteorologists were able to recover the rainfall data for that day from a second precipitation station located east of the airport, but the official wind data as well as the low temperature for Sept. 6 remained missing.

Officially the highest wind gust was 54 mph which occurred on Sept. 15, but there were more than a few other windy days (and nights) during the month, including a stretch between 28-30 which had peak gusts of 49 mph on all three days. (In comparison, during the Jan. 4, 2008 windstorm a peak wind speed of 78 mph was recorded at the airport before power failed, cutting off recording.)

The Sept. 5 storm dropped .40 inches of rain. That amount, combined with 0.52 inches from a rainstorm on Sept. 17, comprised almost half the month’s precipitation which totaled 1.87 inches, an amount 1.12 inches above normal.

Total rainfall for the year is now 9.48 inches, which is 4.35 inches below normal. The total for the water year, which runs from October and ended in September, was 16.88 inches, a mark 3.97 inches below average.

The outlook for this month according to the federal Climate Prediction Center calls for near normal temperatures and near normal precipitation.

Normal highs for Walla Walla fall from 71 degrees at the start of October to 56 degrees at the end. Normal lows fall from 48 degrees to 39 degrees. Normal precipitation is 1.68 inches based on a 30-year average.

Andy Porter can be reached at andyporter@wwub.com or 526-8318.

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