Sunday, February 24, 2013

February 24-27 High-Impact Blizzard

500 millibar analysis reveals that our storm system is currently in the Rockies, and is at the pre-mature stage of a positive tilt. The positive tilt is shown by how the vorticity values (in red outlines) seem to be trying to push to the southwest. In the next 24-48 hours, the system will attain a negative tilt, where the vorticity values will slide east and appear to be pushing to the southeast. In similar fashion to the most recent snow event, this storm will dump intense snowfall on the Plains and occlude (weaken) as it progresses east.

The time for analyzing forecast models has come and gone, as we begin to see swaths of the country stamped with various winter weather headlines. In purple, we see winter weather advisories, which are issued for generally lighter snow events. Pinks show winter storm warnings, and these are the areas that are most likely to see these heavy snowfall amounts in the next couple of days. In an orange-red color we see blizzard warnings, which extend from North Texas and western Oklahoma into southwest Kansas and portions of Colorado to the east of the Front Range. This is where the high-impact blizzard portion of the storm title comes from. These areas will see the worst of this storm in terms of travel impacts and ability to travel.

This is the short range NAM model, an American-based weather model that does fare well in these types of late-winter storm situations. Its forecast for this event holds as much as 31 inches of snow in western Oklahoma in that small red dot. That's nearly three feet of solid snow! The apricot color signifies 24-30 inches, and the light blues reflect 20-24 inches of snow. This is essentially a repeat of what we saw with the most recent snow event: It dumps all of its snow early, occludes and leaves the leftovers for the Midwest and Great Lakes. However, this time, the 'leftovers' may not be so meager. Multiple forecasting sources have informed me that cities like Chicago, IL , Gary, IN and even the region of southern Michigan could be in the running for more accumulating snow than what fell earlier last week.
I did put in city forecasts for this event in addition to the coloring scale. Light Blue is a general 1-3 inches, dark blue is 4-8 inches, and light pink is upwards of 8 inches. I used a blend of the NAM model and forecasts from the National Weather Service, as well as my own opinion on the matter. As far as commutes go, I am anticipating an incredibly messy one for Wichita and Amarillo, where blizzard conditions are expected, especially in the latter city. Chicago and Des Moines will really be 'game-time decisions', as upper air thermal profiles are still a little murky and will ultimately determine how much liquid and snow falls over these cities.



Anonymous said...

Once again St. Louis is on the edge. Snow is too far north, too far south or the systems dissipate upon their march eastward. Somehow we see ice like this past week but rarely ever a strong snow event.

hummingbirdski said...

Chicago news channels will barely commit to snow totals, Milwaukee is not much better. Considering this forecast was right on the money during the last two decent storms, I am inclined to stay tuned here. Thanks for being brave while the vast majority of local guys sit on the fence.

Anonymous said...

Storm after storm after storm and central ohio still misses out once again...

Anonymous said...

Got a solid foot of snow here in Palmer Lake, Colorado, drifts in some places are 3 feet high, though they could be alot worse, but the wind wasn't quite as bad as the models had projected for our area, we got more snow than wind, this is very helpful for some improvement in our drought situation, let's get some more of those storms cranking, what a sliver of good news there, here's to keeping hope alive in Colorado.

Anonymous said...

I'm so happy Des Moines is only getting 3 inches of snow!I love it!Bring on the spring & the warm rains!
Thank you Andrew!