Thursday, February 2, 2012

Winter Storm Getting Underway Across Rockies...

As you can see on the latest composite radar image above, snow is getting underway across Colorado at this hour, and will increase while gradually spreading East/Northeastward overnight, as an upper-level storm system moves into the region from the West.

A variety of Winter Weather advisories, watches and warnings are in effect across the region:

The areas under the greatest threat overnight and Friday are within the orange (Blizzard Warning) and pink (Winter Storm Warning) shaded areas on the map.  Widespread snow, heavy at times, will take place across this region, with strong and gusty winds creating widespread blowing and drifting.  White out to near white out conditions are likely, especially within the Blizzard Warning area.

The latest computer model forecasts through 6pm CST (5pm MST) Friday are generally indicating widespread 6-12 inch amounts, with localized amounts near 2 feet in an axis from near Denver and east-central Colorado up toward the northeast border with southwest Nebraska and northwest Kansas.  The image below is from the NAM model, valid 6pm CST Friday:

...and here is a zoom-in of the same model data, centered on Denver:

Needless to day, this is a potentially dangerous weather situation shaping up for the above areas tonight and Friday, and across (and near) the Winter Storm Watch areas on Friday night and Saturday.

Travel is highly discouraged.  If you live across Eastern portions of the region (in and near the current Winter Storm Watch areas), please make sure that your preparations are complete by midday Friday, as the weather is likely to deteriorate rather rapidly beyond that time.

While continuing to forecast widespread 8-10 inch (plus) accumulations for the Omaha area on Friday night and Saturday, the last 2 model runs have started to trend back on the Eastward extent of the heavier accumulations across Iowa:

It remains to be seen whether this is a model "flip flop" underway or not.  We'll know more tomorrow as the storm system ejects out into the Plains from the West.  Folks in and near the Winter Storm Watch area over Iowa, particularly southwest and southcentral Iowa (particularly to the South of Des Moines) should continue to prepare for the possibility of significant snowfall Friday night and Saturday.

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Anthill_Goddess said...

Hubby and I are sitting here, fully prepared, and thinking of taking bets on what will actually happen when this finally gets here! Ha!

Local central Iowa news is saying 2-3 inches in the DSM area, up to 6-7 out near they're expecting it to drop off significantly as it moves across the state. My concern is that the models they're using are still showing a rain/snow mix over south central Iowa almost all day before turning all to snow Satruday evening. I'm hoping that doesn't become ice!!

Rob White said...


I've posted an update since this post (you've probably seen it already), but did want to address your ice concern. I don't see that being a big threat at this point, the atmosphere will cool pretty rapidly aloft later today, which will prevent a widespread ice threat.

As I recall you're South of DSM, and will therefore have a better chance of heavy snow than they will. "Bullseye" seems to be centering between DSM and the MO border at this time, with even heavier amounts to the West toward Omaha.

Will continue to update the projections throughout the day...