Monday, April 2, 2012

March Grades

March 2012 was a record-breaking month. Portland saw its latest snowfall ever when 0.04" fell on March 22nd. Nine days later, Portland set the all-time rainfall record for the month of March, breaking a 55 year old mark. Portland ended March with 7.89" of rainfall, average is 3.68"!

While Portland set the record, other Northwest cities came close to their rainfall records. March was Salem's 2nd wettest with 9.98", Vancouver's 3rd wettest with 7.81" and Astoria saw its 4th wettest March with 14.13". Hillsboro and Eugene both saw the 5th wettest March on record with 6.59" and 9.94", respectively.

No records were broken with my forecasting grades this month. That doesn't mean it was an off month, however. Accurately forecasting 86% of temperatures and 95% of the conditions, I'd say it was a successful March. The average temperature in the 3rd month jumps by five degrees from the March 1st to the 31st. Couple that with the unpredictability of the spring weather and you wind up with some fairly respectable marks.

There were two "snow" events last month. One at the beginning of March and the bigger event on the 22nd. The first event totaled no snow accumulation even though flakes were falling. One March 1st, I called for a snow/rain mix transitioning into spotty showers during the afternoon with a high of 45 degrees. The forecast worked out perfectly, with a high of 45 degrees and snow turned to rain showers later in the day. I just missed the high temperature by a degree on our second snow day (March 22nd). While working during snow events is stressful, it really gives me the best opportunity to prove my forecasting skills. I never thought that winter weather forecasting would be something I'd enjoy but it is rewarding when an accurate forecast plays out.

For the month of April, I will throw in a new wrinkle to the forecast accuracy. Given the high rain totals last month, I have decided to implement rain amounts into my daily forecast. I will grade the daily totals with a +/- 0.05". Not too many folks notice a difference between 0.25" and 0.30", it just seems like one wet day! I'll consider the rain totals separate from conditions, so there will be a third category for the April totals. Quantitative Precipitation Forecasting (QPF) is a bit challenging so make sure to check back in next month to see how the totals impact accuracy!

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