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THEWEATHERMOGIL:: Snowfall gradients

Yesterday’s winter-spring storm produced lots of severe weather on its eastern flank, but it also generated a band of heavy snow to its west. Just to the east of Chicago, IL, the infamous “rain-snow” line helped to create a rather large snowfall gradient. That gradient (0.44 inches of snow per mile, across a 34-mile distance) gave the National Weather Service (NWS) office in Chicago an opportunity to play up such gradients (Fig. 1). Bravo!

NATL001-ORD-snowfall-gradient

Yet, much larger gradients came into play for the Jan. 26-28, 2015 snowstorm in the mid-Atlantic and Northeast U.S. I refer readers of this blog site to an article I wrote after that event – THEWEATHERMOGIL:: Looking back at an almost perfect winter storm forecast (1/26-1/28/15). Gradients in that storm were some two to three times larger than the one near Chicago yesterday (Fig. 2).

NATL005MAsnowfallGradient150126to150127

What’s important is that people realize that weather-related gradients (e.g., snow, rain, temperature, wind, cloudiness) can be large and affect the viability of current, highly localized forecasts. They can also play a role in how weather is treated in legal and insurance matters.

© 2016 H. Michael Mogil

Originally posted 2/25/16