Greg Perkins [KC9GHZ]

Text From The RACES Tuesday Night Net:

Before we get to the plummeting temperatures, lets get the precipitation out of the way.  Skies through the beginning of next week will remain partly to mostly cloudy.  Wednesday night we will see a 50% chance of light snow, with a chance of flurries carrying over into Thursday.  Friday will also have a 50% chance of light snow, with a chance of flurries following all the way to Sunday night.

Now we’ll get to the big news, our diminishing temperatures.  High temperatures through Friday will only stay in the lower 20’s, with nightly lows only ranging from about 5 to 10 degrees.  Then we’ll see a slight drop in temps, with Friday’s high only reaching the upper teens, Saturday in the lower teens, and Sunday into the beginning of next week we will struggle to scrape above 10.  Nightly lows for this period will hover around 0.

With winds throughout the week staying sustained to at least 10 miles per hour, wind chills could easily drop to 0 or below.

Detailed Forecast Discussion:

One word: cold.

Short waves will continue to periodically rotate out of the Canadian prairie southeast across the northern Plains and upper Midwest, then through the Great Lakes.  One that brought a round of light snow to the region last night brought reinforcement to the cold air today, with temperatures struggling to reach the mid- to upper teens.  Tonight’s clearing sky along with the dry air and the surface ridge moving east into the mid-Mississippi Valley is conducive to a temperature plunge, though with the center of the anticyclone to track east near the Missouri/Arkansas border into western Kansas and Tennessee overnight, there appears to be enough gradient to keep winds from going completely calm, thus providing a little boundary layer mixing and holding temps out of the deep freeze, though local sub-zero readings are a pretty good bet.

The next upstream short wave currently over Saskatchewan will move across the upper Mississippi Valley and upper Midwest later on Wednesday.  Warm air advection sets in by Wednesday morning as the flow backs in response to the approach of this feature.  Southwest winds will help temperatures at least reach the low to mid-20’s by the end of the day. High and mid-level clouds will increase as the day progresses.  As the short wave moves into the area Wednesday night the warm air advection and it’s resulting lift will be enough for a good period of snow showers.  Temperatures may dip a little during the early evening, but with the clouds and the southwest winds they will be near steady or recover back to the upper teens and lower 20’s.  Cold air will gradually return to the region as this short wave shears into the Great Lakes, so temperatures can still be expected to stay in the lower 20’s for Thursday.

Another short wave moves east across the central Plains late Thursday.  This will bring another good chance of snow on Friday as the impulse phases with a strong wave dropping out of central Canada, moving across the upper Midwest and Great Lakes.  This stronger wave deepens the mean upper level trough across central North America as yet another wave drops out of Canada later Friday.

The deepening trough and building upper ridge across the east Pacific into Alaska allows the frigid air to penetrate well south of the heartland.  Temperatures will struggle to get into the double digits by early next week.  No significant precipitation is expected beyond Friday, although the cold cyclonic flow may support sporadic flurries over the weekend.