Sunday, February 24, 2013

5pm Sunday: Blizzard of Oz II Underway

Via Johnny Kelly comes this photo of the snow in the Denver area about an hour ago. As of 4:15pm CST, Denver International has 2-hour, 32-minute average flight delays.

If you compare the AccuWeather Regional Radar at 4:12pm to the posting below, you can see the precipitation has greatly expanded throughout the region.

I continue to believe the best forecast is be a blend of the two models below:
click enlarge
18Z (noon Central) 4km NAM Model via WxBell
As always, my advice is to blur your eyes and don't take the point amounts too literally. For example, in Wichita, one model has about 10-11 inches and the other 10-13 depending on part of town. The (15Z) plume model (not shown) has 13.3 inches. So, for Wichita, I would be thinking about 7 to 14 inches as I'm concerned the models are generating a little too much snow based on the amount of what meteorologists call "precipitable water" (the amount of moisture able to create precipitation).

I would probably reduce the averages of the models by ten to fifteen percent west of the Flint Hills for that region. 

What about the monster amounts in northwest Oklahoma and the surrounding area? The models are so consistent with this feature they are picking up on something. I strongly doubt there will be 42 inches of snow as the one model indicates. What may be occurring is the model is picking up snow thunderstorms and the model is having trouble dealing with it. Regardless, people in that area may have north of 20 inches of snow driven by wind. That equals drifts of ten feet or more. Be prepared to be snowed in for days in rural areas.  

For Kansas City Int. Airport (to pick a point in the metro), one model is 10." The 6am version of the 4km NAM model had 4"at KCI. The newer version has 10 inches but note the odd shape of the predicted snow field. North of my dashed black line, the models have flip-flopped. I would estimate around 8 inches in north KC and 13+ in the far south parts of the metro (i.e., Belton, Kenneth, Stillwell).

I don't expect any part of Kansas north of the I-70 counties to have more than eight inches west of KC Metro and maybe not there.

The axis of the heaviest snow seems to be from about Woodward, OK to far southeast Wichita Metro to Ft. Scott to the Lake of the Ozarks and Jefferson City.

The huge difference between the The Blizzard of Oz II and last week's storm is the wind. This chart is valid at 6pm Monday evening. The area of orange on the KS-OK border is gusts above 60 mph. The whitish area is gusts above 45 mph. With winds this strong, power failures become a real possibility. Below is the model from this morning but the newer version looks about the same.
There will be some isolated areas of freezing rain which will cause slick roads and will enhance the potential for power failures. Not looking for any major areas of freezing rain accumulation.

Updated precautions considering the storm is already in progress:
  • Fill your gas tank. Make sure you have an ice scraper. 
  • If the snow is sufficiently wet, there will be power failures due to the high winds and snow loading of lines and trees (branches leaning into the wires). Get a auto power inverter that can keep your cell phone or computer charged. 
  • If you must keep medicine chilled or run other appliances, get a portable generator. Make sure you follow all instructions to the letter. It is too late for an electrician; so do not try to install a permanent generator yourself.
  • Refill prescriptions east of Interstate 135. Do not go out into the blizzard to pick up items once it begins.
  • Go to the grocery store to get any necessary food
  • Go to the ATM and get cash. 
  • Make preparations for your pets and farm animals
In the strongest possible terms, I urge you not to attempt to travel in or through the blizzard area once it begins.. Airline travel is disrupted in Colorado and airports in Kansas and Kansas City will either close or most all flights will be cancelled.

If this forecast is correct, I believe I-35 will be closed in Kansas and northern Oklahoma and U.S. 54 will be closed as well along its extent from Dalhart, TX to Jefferson City, MO. I-70 might be closed again in Missouri but that would be after dark Monday evening.

When does this start?
  • Denver: In progress.
  • Garden City, KS: 11pm to 3am.
  • Hutchinson, KS: 4am to 10am.
  • Woodward, OK: 1am to 4am. 
  • Wichita: 7am to noon.
  • Topeka: Noon to 4pm 
  • Kansas City: 3pm to 7pm (note: KC is one of the geographically largest metro areas in the U.S. Areas west and south will see snow first)
  • Jefferson City, MO: 6pm to 10pm Monday
This will be my last "forecast" since the event has begun. I will post updates as the storm progresses.


  1. Mike, what does the dotted line with the question mark running across Missouri in the NAM model indicate? Does it indicate a possible freezing line south of which everything may be rain and not snow? I ask because Central Illinois NWS is currently forecasting all the snow to stay northwest of the Illinois River and everything south of there (Springfield, Champaign, etc.) to be just rain. This will impact us Tuesday morning, probably about 12 hours after it hits KC.


  2. Hi Elaine: The dotted line is explained in the text. See paragraph that begins, "For Kansas City Int. Airport ..."

    It means the models have been highly inconsistent north of that line and I have much less confidence (thus the "?") that area.

    Please don't extrapolate amounts to central Illinois. I think the storm will weaken before reaching your area.

  3. Hi Mike, I'm wondering if it is okay with you to post a link to your Blog on my Facebook page? It's not a business or group page, just my own personal account. Thanks for keeping us informed.
    Rick Stockton

  4. Yes, please do.

    Anyone is welcome to link to the blog with proper credit. Thank you for asking.

  5. Thanks Mike... guess I read your post a little too fast :-)


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