Another Record Setting Warm month

By Russell Russ

The month’s low temperature of 28 degrees was observed on May 11. The high temperature of 87 degrees was observed on both May 2 and May 26. The average mean temperature this month was 58.8 degrees, 4.2 degrees above the May normal. There were two record high temperatures this month. The high temperature of 84 degrees on May 1 replaced the 81 recorded in 1936 and the high of 87 degrees on May 2 shattered the 80 recorded in 1933. It was Norfolk’s fourth warmest May in the last 79 years. The warmest May on record was in 1991 with an average mean temperature of 59.7.

The total precipitation recorded for the month was 2.89 inches, 1.46 inches below normal. For the 2010 calendar year, through May, the total precipitation amount is 21.84 inches, 0.96 inch above normal. There were six thunderstorms this month, but around here none were severe in nature.

With very light flurries falling on two separate days there was a trace of snowfall this month. The May normal snowfall amount is 0.4 inches. For the calendar year, through May, the total snowfall amount is 53.2 inches, 13.1 inches below normal. A final look at the 2009-10 winter season snowfall amount shows that Norfolk recorded 73.3 inches from October through May. This is 17.9 inches below normal. It is a bit hard to believe, but the last time we saw more than two inches of snowfall was way back on February 27.

May started and ended on the warm side, but we did have a few cool mornings during the second week of the month. There was a hard frost at the weather station and many locations during the early morning of May 11 when some lower elevation locations around town dipped into the mid to upper 20’s. We missed a record low temperature on May 11 by just one degree. The record warm temperatures over the last few months resulted in a much earlier blooming year for many plants. The lilacs, laurel and many others were nearly two weeks ahead of normal.

A very interesting optical phenomenon occurred over the skies of Norfolk on May 17 when a circumhorizontal arc appeared around noontime. A circumhorizontal arc is a huge, multi-colored band running parallel to the horizon with its center beneath the sun. Often only parts of the band are displayed in the high cirrus clouds, but on this day one whole cloud was lit up with this bright coloring. The phenomenon only occurs when the sun is high in the sky and is formed by sunlight entering horizontally-oriented flat hexagon ice crystals through a vertical side face and leaving through the near horizontal bottom face. Where you are located on the Earth determines who can see one. The factors involved in its formation are not all that rare in the Continental U.S., but it still is not a common thing to see. It is the first one I’ve ever seen and because of its size and brightness it startled me when I first saw it. Luckily it lasted for a good half hour and even better, I had my camera with me at the time.