FOR WHOM THE SNOW BELL TOLLS...


After several days of speculation, the bell is set to toll on a snowy period around the central Midwest. Three separate snow producers are in the pipeline and on the way. Get your shovels ready, things are looking flaky. Details below on the coming trifecta.


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SYSTEM NUMBER 1

The first snow producer arrives Saturday night as a bout of warm air advection arrives on return flow. The forcing from the upglide will generate a 4-6 hour window for light to occasionally moderate snow, especially in the NW half of my region. As it appeared yesterday, the north experiences the best lift and that is where the heaviest amounts from this wave are likely. Most of my area from I-80 north can expect 1-3” totals. The area north of HWY 30 stands the best chance of 2-3” amounts. With snow ratios greater than the standard 10:1 average, I used the Kuchera forecast method for snowfall amounts which takes that issue into account. Here's the raw model output for system 1.


The EURO


The GFS

The Canadian GEM

SYSTEM NUMBER 2, THE BIG KAHUNA

This is the energy that appears to be the big Kahuna with the potential for a significant band of heavy snow that in some part of my area could exceed 8 or more inches. The focus currently is centered on the southern half of the region. However, there remains some essential differences in modeling that has kept confidence lower than I would like 48 hours from the event. Here's the options on the table model by model.


THE EURO

As has been the case for several days the EURO has been the most bullish on the strength of the storm and its impacts later Monday and Monday night. It has also been the furthest north since day 1. After trending south during a mid-week adjustment the model has been consistent the past 48 hours targeting the area from roughly HWY 20 south with a major snowfall. The EURO depicts this with standard 10:1 ratios. Keep in mind this includes what falls Saturday night.

Going with the Kuchera method which accounts for higher ratios, the EURO is quite impressive with these raw totals. I stress this is just model output and not a forecast. I thought long and hard about even showing these numbers as I don't want to start the hype train. However, within the heart of the heavy snow swath the model has been consistently showing 12"+ totals for days. I think there is enough evidence to cautiously say a band of 10-12" snow is a possibility somewhere if the EURO wins this fight!

THE GFS

The GFS has come a long way the past 48 hours from no storm to a track much closer to what the EURO indicates. It's thermal profiles are a bit warmer, it's faster, and it still remains a bit further south but I'm pleased to see the gap has narrowed dramatically between the two. Here are the 10:1 ratios which are less than the EURO due to the warmer profiles, speed, and less QPF from a slightly weaker system.

Utilizing the Kuchera method and higher potential ratios amounts increase to this.

THE CANADIAN GEM

That leaves us with the Canadian GEM. It's now the odd man out as it tracks the storm further south. That shifts the heavy snow axis into northern Missouri, southern Iowa, and central Illinois, essentially near and south of HWY 34 in my area. Little if any snow falls north of HWY 30. Here's the 10:1 ratios.

The Kuchera method with higher ratios doesn't look much different as the heavy snow falls in warmer temperatures keeping ratios close to 10:1 in both scenarios.

SYSTEM NUMBER 3

With system 3 fast on the heels of number 2, there's bound to be less in the way of moisture and minimal chances for this to deepen to a point where it could produce much more than an inch of two of new snow. Just the same, it would be the icing on the cake in a 5-6 day period where some part of my area has the potential to see a foot or more of snow. We'll see how much energy and moisture is available for number 3 after the first two systems do their damage.


In summation, system one Saturday night is just a warm-up for the second. Number one is a 1-3" event, while number two Monday is at least a 5-10" storm where the heavy snow band sets up which looks most likely near and especially south of HWY 20. I expect a winter storm watch will be issued at some point Saturday for much of the southern 2/3rds of my area if trends hold. Again, system three Wednesday could drop another 1-2" over most of the region if data remains consistent.


I hear the bell tolling and that means its time for me to call it a day. Stay tuned for updates Saturday. Roll weather...TS



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