Friday, February 3, 2012

Update on Central Rockies/Plains Winter Storm...

Snow continues to fall in a swath extending from central Colorado into western Nebraska an extreme northwest Kansas at this hour, and is beginning to mix in with the rain on an increasing basis across adjacent areas:

"Future radar" imagery from the NAM Computer Model suggests that precipitation should be falling entirely in the form of snow by 10pm CST this evening across most of Nebraska, as well as northwest and northcentral Kansas:

The snow is likely to become heavy at times over northwestern and northcentral Kansas, into southcentral and southeastern Nebraska.

The same computer model continues to indicate a swath of 6-10 inch snow accumulation by Midnight this evening in a band from northwest and northcentral Kansas into southcentral Nebraska:

This heavy snow swath is forecast to expand and intensify toward the Northeast overnight, with a cluster of 10-15 inch snows indicated over southcentral and southeast Nebraska by 6am CST Saturday morning:

Heavy snow is then expected to spread Eastward into adjacent portions of west-central and southwest Iowa during the day Saturday.  Here is what the latest run of the model projects for 12 Noon CST Saturday and 6pm CST Saturday, respectively:

The following images are zoom-ins of the same model forecast for total snow accumulation, centered on the Omaha and Des Moines radar sites, respectively:

The models have continued to oscillate North-South by about 50 miles or so with the axis of heaviest snow during the last few runs, so keep this in mind when looking at the above products.  This certainly gives us a good idea as to the most likely areas to be affected by heavy snow, but particularly the Eastern and Southern extent of the heaviest snow over Iowa remains a bit in question at this point.  Trends continue to indicate that areas both West and South of Des Moines are likely to pick up more snow than the city itself will.  

The average of all of the various forecast models over the last 12 hours yields a snowfall forecast of 6 inches in Des Moines:

...and 9 inches in Omaha:

I tend to agree with the Omaha assessment at this time.  I think the Des Moines forecast is on the high end right now.  I think a 6 inch total is more likely to the West and/or Southwest of the city itself based on current trends.  The key will come down to how far East the heavy snow bands set-up later tonight and early Saturday.

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Anthill_Goddess said...

I'll take about 4 inches, locally and had to laugh as this final run (since it's starting to rain here, finally!) and out local people are a bit closer in agreement!!

The last run they showed at 10pm had the heavier band riding just north of I-80 and stopping a county before DSM (Dallas county)and having the highest totals near Carrol (?) county which I think is what you're showing (I get the 99 counties mixed up sometimes!!).

Thanks, Rob, for your heads-up on this was a hum-dinger, for sure! Glad everyone, so far as I've heard, is making it out in good shape!

Rob White said...

Anthill, Thanks, glad to hear you're doing well and enjoying it! Please do let me know how much you end up with when it's over this evening!