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THE FORGOTTEN SNOW OF MAY 1947....

I've already heard COMPLAINTS about the heat we experienced over the holiday weekend. Yea, it was toasty and most of my area set records Sunday and Monday in the range of 93-97 degrees. Here's Sunday's highs with readings of 102 in Sioux City and 101 In Omaha.

But, if you're one of the gripers, just think about what people were legitimately crabbing about on the same date in 1947. Snow! Up to 10" fell over the NW third of Iowa into SW Wisconsin. The heavy wet snow clung to trees, bushes, power lines, and telephone lines causing severe damage. Around Sioux City where it was 102 Sunday, 10" of snow was measured on the same date 71 years earlier. Now that's something to complain about! Look at the extent of the snow.

Some specific snowfall totals from the National Weather Service.

A picture of the snow from Westby, Wisconsin taken after the snow stopped falling May 29th. Man!

Here's a nice account of the storm from Jeff Boyne of the NWS in La Crosse, Wisconsin.

The Nearly Forgotten Snow Storm of May 27-29, 1947

Jeff Boyne, NWS La Crosse Climate Services Focal Point

Through the years, this late season snow storm has been purged from memories of many people in northeast Iowa, southeast Minnesota, and western Wisconsin. Maybe it is that people do not want to think about snow in late May or that the snow quickly melted, but very few remember this storm. If it was not for this author stumbling upon a 9 inch snow amount in Viroqua, Wisconsin this reminder that snow storms can occur this late in the spring in the Upper Mississippi Valley may have never been written.

On the morning of May 27, 1947, a developing low pressure system was located over central Nevada. It was this low which would be responsible for the snow storm over the Central Plains, Upper Mississippi Valley, and Upper Michigan from May 27th through May 29th. A strong arctic high pressure system was located over the Mackenzie Basin in northwest Canada. This high would provide the cold air needed for a winter storm to develop. A mixture of rain and snow developed over Colorado and Wyoming during the day on May 27th and changed to all snow during the night as the low deepened and moved slowly east through southern Colorado. On the morning of the 28th, the high pressure center had moved rapidly south to southern Saskatchewan. This high pressure area brought unprecedented cold for late May to North Dakota. Temperatures fell to as low as 15 degrees at Eckman, which is located near the Canadian border. In addition, the mercury fell to 23 degrees at Bismarck which is the lowest ever recorded there after May 20th. Meanwhile, below freezing temperatures were found across Montana, Wyoming, northeastern Colorado, western Nebraska, northern Minnesota, and western South Dakota. The sub freezing temperatures caused a partial to total loss of fruits and tender plants. During the day, this cold air surged southward across eastern Nebraska, eastern South Dakota, Iowa, southern Minnesota, and Wisconsin. Many cold maximum temperatures were established across the region for the day. At the same time this was occurring, the area of low pressure was continuing to strengthen as it moved east through southern Kansas. From the evening of the 27th through the 28th, this low produced a 6-12" snow band from southeast Wyoming east across northern Nebraska into northwest Iowa. The heaviest snow in this band was found in Alliance and Harrison, Nebraska where 12" had fallen. The weight from the heavy wet snow caused considerable damage to power lines, telephone lines, telegraph lines, trees, and shrubs. During the late afternoon and evening of May 28th, the surface low began to move northeast across northern Missouri, northwest Illinois, and southeast Wisconsin. The reason for this change in direction was due to a strong upper level disturbance that had dropped into the base of the upper level trough over Nebraska during the day. This upper level disturbance caused an amplification of the upper level ridge over the Ohio Valley and much of New England. As a result, temperatures in this region climbed into the 80s instead of the 50s and 60s which were seen the day before. However on the cold side of the system, temperatures remained in the 30s and 40s in the Upper Mississippi Valley. In addition to the cold temperatures, rain changed to snow across southern Minnesota, northeast Iowa, and across much of Wisconsin. This was the latest snow ever reported in a season in this area, with some places experiencing their biggest May snow storm on record. From the late afternoon of the 28th into the early morning hours of the 29th, 7-10" of snow fell across Allamakee County in northeast Iowa, and Vernon, Crawford, southern Monroe, and Richland Counties in southwest Wisconsin. The heaviest snowfall amount was 10" in Gays Mills, WI. Meanwhile, a 7-9" band of snow fell across northern Adams, Waushara, Winnebago, Outagamie, and Waupaca Counties in central and east central Wisconsin. The weight of the heavy snow caused severe damage to power lines, telephone lines, bushes, and trees.

Through the years, this late season snow storm has been purged from memories of many people in northeast Iowa, southeast Minnesota, and western Wisconsin. Maybe it is that people do not want to think about snow in late May or that the snow quickly melted, but very few remember this storm. If it was not for this author stumbling upon a 9 inch snow amount in Viroqua, Wisconsin this reminder that snow storms can occur this late in the spring in the Upper Mississippi Valley may have never been written.....................................................................................

Today promises to be another toasty spring day with most areas back in the lower 90s. Some spotty thunderstorms are possible, mainly in the afternoon. Later Tuesday night or Wednesday, the remnants of Alberto (mainly its moisture) and some energy ejecting out of the Plains should increase the coverage of showers and storms. A few strong storms are possible but the main impacts from them should be locally heavy downpours, although they look rather spotty.

That's it for now, stay cool and loose! Roll weather...TS

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