COLUMBUS, Ohio (WCMH) — Much to the chagrin of all of us hoping that spring is finally around the corner, the jet stream is diving far to the south for the third week in a row, ushering in a March-like pattern of wind, chilly air and periodic showers. Snowflakes and graupel mixed with the rain in places.
The reason is an “Omega block” in the jet stream resembling the Greek letter (Omega) that forces cold air far to the south over the eastern half of the country. Upper-level low pressure swilring over the eastern Great Lakes sends pieces of energy digging southward expanding the chill and creating bands of rain and snow showers.
High temperatures on Monday were the lowest on May 1 since 1909. By early Tuesday, snow accumulated from 2 to 7 inches in the highest elevations of western Virgnia northward through West Virginia and southwestern Pennsylvania.
Parts of northern Wisconsin and Upper Michigan received record late falls of one to two feet the past several days, and up to 32 inches at Ishpeming Township, Mich. Marquette received 19.8 inches on May 1, setting an all-time May snowfall record. The storm total since April 30 reached an incredible 28.7 inches!
A turn to chilly weather in late April followed early warm spells. April averaged slightly above normal in temperature and a little below average in precipitation in central Ohio, A few notable storms later in the month produced large hail.
The warmth was impressive, with a June-like reading of 84 degrees in Columbus on April 20. Several days later, a strong cold front ushered in unseasonably chilly weather that was followed by patchy frost and instances of graupel (tiny frozen snowfalls).
Indications are that May will likely play out in the reverse of April: A very chilly beginning, then a seasonably warm finish. Even as early as this weekend, temperatures will rebound into the 70s, in time for the Kentucky Derby.
The average high temperature in early May is in the upper 60s in central Ohio, which climbs to the upper 70s by Memorial Day.
NOAA’s Climate Prediction Center is projecting slightly above-average temperatures and near- to below-normal precipitation for the majority of the month in the upper Ohio Valley region.
The wettest areas will probably be the Southeastern states, which is a continuation of the late April southern storm track in the first half of May.
The demise of La Niña — cooler-than-average sea surface temperatures in the central and eastern Pacific — will help reshuffle the deck regarding the overall circulation, possibly replaced by El Niño by early autumn, which has a different climatological pattern (wetter southern U.S. in fall/winter, drier north).
