Ag Weather Forum

Following are details from a post on the NOAA Climate.gov web site by NOAA climate scientist Tom Di Liberto on the prospects for spring snows. It is indeed not out of the question, although this year's occurrence was indeed one for the records. -- Bryce

"Snow doesn't stop the moment that winter becomes spring on the calendar -- a fact that those living in the northern Plains know all too well right about now. Following on the heels of four nor'easters that buried parts of the East in March, the recent storm got us thinking: What is the latest date that measurable snow has fallen in different parts of the United States?

The dates of latest snowfall can reach into late June for regions along the Rockies and Mountain West, even stretching into the desert Southwest. Meanwhile, the latest snow for areas in the southeastern United States has come in March or early April.

A lot of this pattern can be attributed to features inherent in the geography of the United States. The higher the latitude and the higher the terrain, the later in the year the snow ends. Meanwhile, places farther south and closer to big bodies of water (like oceans) have experienced their latest date of snow fall on the earlier side -- looking at the southeast.

The interesting wrinkle is that the change in date of the latest final snow of the season does not follow a strictly east to west line across the country, even to the east of the Rockies, as it would if latitude were the only influence. Instead, it appears to occur on a diagonal across the Great Plains and into the Midwest. Why is that? Well the answer lies both to the south (the Gulf of Mexico) and the north (Canada).

As the calendar moves into spring, warmer air from closer to the tropics and over the Gulf of Mexico begins to moderate temperatures enough over the southeast to make it difficult for temperatures to be cold enough for snow. Meanwhile, cold air that resides in the interior of Canada can still funnel south, bounded on one side by the Rocky Mountains, allowing for the occasional late spring snowfall, even as far south as higher elevations in New Mexico."

The full article with graphics is at this link: https://www.climate.gov/…

Bryce

Twitter @BAndersonDTN

(AG)

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