***Official 2021 Weather Thread***

FDWxMan

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Jan 31, 2009
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Des Moines

So, if you're interested, this is a cross section view of the atmosphere.

Red squiggly line is the temp as you go up. Warmer to right, colder to left.

The little yellow stretch on that line is the Dendritic Growth Zone (DGZ). It's the area where the temp is between -12 and -18 C. If you're making snow in this region of the cloud/atmosphere, you get great big dendrites (think the shape you cut out of construction paper in elementary school.

Now, how do we know if that's the part where snow will grow/form? Need two more things: high humidity, and lift/upward motion.

Green squiggly line is dew point. It's hugging the air temp through the lower half of the atmosphere, humidity is definitely high.

That leaves the upward motion or omega. Omega is the horizontal barbs sticking out on the far left.

The red ones indicate upward motion and the farther they extend to the right, the stronger the upward motion.

So we have virtually 100% humidity through the DGZ, and lift is maximized right in the middle of it.

=Snow Jackpot as Taylor said.
 

FDWxMan

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Jan 31, 2009
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This is also why snow totals get so tricky, change the temperature where the snow is forming at, it switches the liquid ratio.

Same if you move the lift around. Or your lift is strong, but the humidity is low.

Lots of things can be off by just a hair and have a compounding error effect that screws it all up.
 

Jer

CF Founder, Creator
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Dark Sky shows 10-15. It’s like Earl turned into a virus and has taken over all forecasts. Would be amazing to see a 15” snowfall in 12 hrs.
 
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cycloner29

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Dec 17, 2008
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Looks like it is pushing further north with people along HWY 20 getting more according to Jeriann this morning.
 
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wxman1

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Dark Sky shows 10-15. It’s like Earl turned into a virus and has taken over all forecasts. Would be amazing to see a 15” snowfall in 12 hrs.

We got 14" in around that time in Wichita once...it didn't go well at all down there. My memories from that storm were finding out that they didn't plow residential streets because "it would create snow piles around parked cars and at the end of driveways". It was also the night of the KU game at Hilton in 2013...ya know the one where we got jobbed and Mr. Weatherwax had a conversation with Mr. Self as he left the floor. Any who the snow was so heavy and wet that it stuck to the satellite dish so here I was in the middle of a major snow storm standing on a step stool using a broom to clean off the dish.
 
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