Sunday, January 30, 2011

Major Winter Storm This Week

A major winter storm will impact a large part of the nation this week.  This particular post focuses on the period Tuesday through Wednesday.


A strong upper level low pressure system was moving onshore in the extreme Northwest part of California this afternoon:



This system will drop southeast along the Arizona/New Mexico/Mexico borders through Monday:


then lift back Northeast into the southern and central Plains Monday night into Tuesday:






This system, in combination with a surge of cold, arctic air from Canada, will produce widespread, wintry precipitation in a large area from the central and southern Plains into the Midwest and Ohio Valley Tuesday and Wednesday:
Within the larger overall winter outlook region, locally significant amounts of snow and/or ice are forecast for many areas.


Significant ice accumulations are possible from extreme northeast Oklahoma and southeast Kansas, Northeastward through portions of Missouri (including the St. Louis metro area), central & southern Illinois and Indiana (including the greater Indianapolis area), into west-central Ohio:
Within the red shaded areas on the map above, one quarter to one half inch of ice accumulation is likely, with locally heavier amounts possible.  (The integrity of trees and power lines comes into question with one quarter inch of ice or more).  In addition, strong & gusty North to Northeast winds of 30-40 mph with gusts to 50 mph will create further problems.  Significant power outages can be expected in these areas.


Locally heavy snow may also fall over parts of the ice storm regions during the last 12 hours of the event (see outlook and maps below).  This would obviously further aggravate an already very hazardous situation in these areas.


Heavy snow will be widespread from portions of central and northern Oklahoma into east-central Kansas, northern Missouri (including the Kansas City metro area) into northern Illinois (including the Chicago metro area) and extreme northern Indiana and southern Michigan:




Snowfall totals of 6 inches (with locally heavier amounts) will be widespread within the area outlined in the lighter blue shading on the map above (including the Oklahoma City & Tulsa metro areas).  Widespread amounts of 10-15 inches, with locally heavier amounts, are likely within the darker blue outline (including eastern parts of Kansas City and all of the Chicago area).  One computer model is currently forecasting a "bullseye" of 15-20 inch snowfall totals for the greater Chicago area by 6am Wednesday morning.

In addition to the heavy snow, widespread winds of 30-40 mph with gusts to 50 mph will create blowing and drifting snow.  Blizzard to near blizzard conditions can be expected for much of the areas outlined above.

Surrounding the 6 inch plus snowfall area, a large area of 3-6 inch snow will cover the Plains from the Texas panhandle and western Oklahoma into much of Kansas and adjacent portions of Nebraska and Iowa.

Currently, the National Weather Service has Winter Storm Watches (blue/grey shading) and/or Blizzard Watches (lime green shading) already in effect for much of the regions outlined above, valid late Monday or early Tuesday through Wednesday:



It's still relatively early in the game for this system, however the above should give you a good idea as to how the event is expected to unfold.  Residents of the central and southern Plains into the Midwest and Ohio Valley should prepare now for the approaching winter storm.  Listen to local media for the latest updated forecasts, watches and warnings for your area.

We'll make additional postings here as conditions develop...

8 comments:

Anonymous said...

you've said exactly what the weather models are predicting... However, they are not accurate.. and in my opinion the storm system will drop more south and take a more north easterly/east direction then north. Your looking at significat snow and ice in central and northern texas. The midwest will get a dumping.. More interesting is that some places in Texas will get over 6 inches of snow!!

KE5WLM said...

Up to two feet of snow is forecast for the Sacramento Mountains of SE NM. Up to 20" is forecast for most of the rest of the mountains of NM Mon-Thu.

High temps across NE NM will only be in the single digits Tue-Wed, with lows diving down to around -20F.

Potentially life threatening wind chill values of at least -10F to -20F across the eastern one third of the state Tuesday into Tuesday night.

Highs across SE NM will struggle to get out of the teens and twenties Tuesday, with lows in the single digits, or colder, Wednesday morning. Wind chill values of -10 to -20F possible. At least 1" - 4" of snow expected.

Nearly the entire state is now under a Winter Storm Watch. Huge travel impacts across NM form this storm Mon-Thu.

Looks like potentially the biggest storm to impact NM since the three storms of Christmas of 1997.

Rob In Texas said...

To Anonymous: Thanks for the post. I have to disagree on a few points, however. I have not said 'exactly what the weather models are predicting'. I treat the models how, in my opinion, they should be treated, which is as a guidance tool only. As I pointed out toward the end of the post, it is still early in the game and things can change, but right now, this is both an informed and responsible forecast, based on current trends and model guidance. I have included much of the Texas panhandle and parts of northwest Texas in the "significant winter precipitation" category. Right now that looks like less than 6 inches of total snow/sleet accumulation, but that can of course change over time as we see exactly how the system comes out. (As a disclaimer, through 18z, the models are trending further North, not South, with the major storm track). A blend of past experience and model guidance/trends suggest a major storm track along the path outlined thus far...but things can certainly change.

Rob In Texas said...

To KE5WLM: Thanks for the comment. I deliberately left out the intermountain region and adjacent Plains from my earlier post. Not because I necessarily "wanted to" but because time did not allow for me to make a detailed post regarding conditions in those areas during the initial phases of the storm. Certainly residents of not only New Mexico but also Colorado should stay alert and prepare for winter weather conditions beginning Monday and lasting into Tuesday...

Anonymous said...

I appreciate your reply and hear what your saying. But I'm going to stick close to my guns on this one. Its looking highly likely to me that central and north texas will see some significant amounts of winter precip. Dallas is definately under the gun and will quite easily see in excess of 6 inches. A large portion of Texas will exceed 6 inches of snow. If you look at the latest precip models they are now showing a large area of central texas will get anywhere between 3/4 of an inch and 1.5 inches of rain. If that rain falls as snow then you could quite easily times that by 5, 10 or 20.

The storm system will keep on dipping a little farther than the models show before it decides to move north east/east. The path of the system will dip below San Angelo ( just above Sonora) and then start to track north easterly/east towards Austin... All the areas north of El Paso, Fort Stockton, Sonora, Austin line will generally get snowfall and ice totals of between 1 and 4 inches.. Some areas will exceed 6 inches.. Especially the central breadth of the lone star texas..

Rob In Texas said...

To Anonymous: Thanks for your reply to my reply. I am curious about your statememt: "The storm system will keep on dipping a little farther than the models show before it decides to move north east/east..."

Could you share with us your reasoning behind this assumption?

Thanks!

Anonymous said...

Hi,

Sorry i should have explained my assumption.. But honestly I'm just going off my own experience and mostly guessing.. However, the models I have do indicate a more of a northerly track.. but one of the models show a more southerly.. all the way down past Sonora! But as we know the models are always a little off.. so i do my math and came to the assumption that the storm should keep dipping just past san angelo before it starts to move east/north easterly. I'm also basing my prediction on the huge snow storm that hit Texas back in the 50's, I think? The set up is very similar.. alhough this is going to be a quick moving storm in comparison.

Anonymous said...

To annonymous, from annonynous. LOL.

I live in Abilene our local radio station are forecasting 10 inches for us!!