KCRG%20big%20horizontal%20banner_edited.

PICK YOUR WEEKEND POISON, TOUGH WEATHER AHEAD...

LIMITED COPIES LEFT:

A SECOND PRINTING OF MY NEW BOOK IS ON THE WAY...

NEW COPIES OF DERECHO 911, IOWA'S INLAND HURRICANE ARE AVAILABLE. Around Christmas we sold the last of the 1500 copies of our book on this historic thunderstorm, the most damaging in U.S. history. Due to continued demand we ordered a limited number of 250 for those of you interested in having the most authoritative account of this extreme event. Books are selling fast so don't miss this opportunity to own the weather story of a generation. You can get yours at derechobook.com


I ordered one of your Derecho books about the storm in Cedar Rapids, IA back in December. I love it! I had also bought one that the Cedar Rapids Gazette sold. Your book by far is so much better, you have a lot more pictures and it just shows more. Thank you for putting a wonderful keepsake together! Do you have any left? If so can you tell me how to get at least one more.

Thank you so much! Penny Brecke


BREAKING NEWS

This just in, two feet of snow fell today. Dang it all, I didn't see that coming!



PICK YOUR WEEKEND POISON

We've a wintry weekend ahead of us that includes bitter cold temperatures, nasty wind chills, and some snow, most of that will be found near and south of HWY 30. Pick your poison but none of it is very good unless you are a descendant of the Polar regions.


CLIPPERS AND FLUFFY LIGHT SNOW

As it stands now, three clippers are set to cross the region in the next three days, (that's one per day... yes, I figured that out all by myself). None of these has much surface reflection and moisture is scant. However, the cold air will squeeze out what water vapor is available and where there is enough lift, which seems to be the southern half the area, several inches if new snow are possible over the 3 day period.

As you can see the first in this series is due to arrive Saturday in the south where a winter weather advisory is posted from 9:00am to 9:00pm.


This is the official snowfall forecast and I think overall it's in the ballpark. The exception may be in the advisory area from near HWY 34 south. I think the potential is there for amounts more in the 2-4" category. The other concern I have is how far north the snow band gets. There is some very dry air in place that will make a sharp cut-off to the northern extent of the snow. Right now that appears to be very close to HWY 30 so that's roughly where the 1" line stops. That could end up closer to I-80 if the dry air ends up being a bit stronger. From there south amounts gradually increase into the advisory zone.

Here's the latest snowfall outputs from the various models. These are not forecasts, just raw model guidance which is what we blend to make forecasts. I'm using the Kuchera snowfall method on hi-res models which takes into account snow ratios that should be closer to 20:1 than the standard 10:1. That's due to the very cold air the snow will be falling into. That should make for some nice powder that will fluff up nicely. It's far easier to remove too when you can whip if off with a broom.


The 3K NAM

The 12K NAM

The GFS

The HRRR

The Canadian GEM

Two more clippers follow, one Sunday and another by early Monday. Each of these has the potential to drop another 1-2" of powder. The Sunday system is directed more at the south and the one Monday is further north encompassing most of my area. I say again that none of these is overly impressive but the nickle and dime effect adds up.


FRIGID ARCTIC AIR

All of this takes place within an Arctic air mass that has settled to the south. You can see the ridging associated with the massive dome of cold air extending from a 1061mb high (that's huge) centered over the Yukon to a weaker center in Iowa Sunday night. It's cool to see how the cold air drains into the country along the eastern spine of the Rockies...a natural funnel if you will.

These are temperature departures Sunday morning.

The GFS goes ballistic with lows Sunday morning as skies clear and Arctic air deepens over the extensive snow pack. It has widespread readings of 20-25 below which would challenge records.

The EURO is more tropical (and dare I say kinder) with lows more in the range of 13 to 19 below.

For those who care, here are the record lows for Sunday morning.

Dubuque.........-26 in 1875

Cedar Rapids...-22 in 1905

Moline.............-17 in 1977

Burlington.......-11 in 2014


Winds will play a critical factor in the intensity of the chill. If they back off soon enough that -22 to -25 range is attainable, particularly with fresh snow and plenty of it. This was the reported snow cover Friday. Much of the area from I-80 north has depths of 12-18". By Sunday morning even the leaner areas of the far south should have added 2-4" to what exists. The deeper the snow cover the colder the temps.

HARSH WIND CHILLS

Another aspect that will come into play is the old wind chill factor. I've been in 25 to 30 below with no wind and it's not pleasant but it is tolerable if you are dressed properly and moving around. I would take that anytime over brisk winds and a wind chill of 10 below, even zero. Anyway, while winds won't be more than 10-15 Saturday night that propels wind chills into the potentially dangerous category of 30-40 below. A wind chill warning is coming. This is what the GFS has for chills. It may be a hair on the cold side but it's still rude and I say...no thank you sir!

Have you picked your poison yet? I have and it's called Portland, Maine where i reside until May 1st. It was 39 here Friday and outside of one big snow and another moderate one it's not been much of a winter in Casco Bay. Ha, just my luck. Oh well, the sun will rise tomorrow and it will be a new day. Seize the moment and be thankful for all your blessings! Roll weather...TS

ARCHIVED POSTS
RECENT POSTS
© 2020 Terry Swails