Winter Weather

Mar 202013
 
One Computer Output for Snow by Thursday Night

One Computer Output for Snow by Thursday Night

This is an update to the snow potential for tomorrow.  We also have a wet weather system this weekend. All precipitation is good at this point but…

(Note: I’ll continue to mirror weather posts here but the favored site in the future will be the Daily Weather Blog at Ozarks Weather)

Snow Update

A narrow but intense band of snow is still forecast to develop on Thursday.  The model runs over the last 24 hours since my last blog are about the same with track of the snow varying a bit with bigger fluctuations in snow amounts.

I put up my snow forecast on the drawing board this morning.  My 4″ plus area hasn’t changed a whole lot.  The “plus” could mean 6″ or even more but with these heavy wet snows riding on a small area of lift, it is difficult to know where the upper limit to snow is or where exactly it will fall.

The ensemble runs I mentioned yesterday have narrowed their range (not as extreme) and the mean now for Springfield is right around 4″.

Put me down for 4″ of snow in Springfield. This snow will really get going just after noon on Thursday and last into the early evening.

Note that snow that falls during the daylight hours will melt pretty quickly while snow which falls say in south central Missouri or north central Arkansas will “stick” for a time longer during the evening, overnight Thursday and very early on Friday.

The crazy thing is that this snow is not connected to a cold front. So in all probability, rain showers will take over perhaps in some areas by Friday morning and last into the day on Friday.

My Seven Day Temperature Forecast

Wet and Chilly

Total Liquid Through Weekend

Total Liquid Through Weekend

The weekend looks damp and cold. We will be in the “warm” sector of a developing low pressure system, meaning forties will be around on Friday and Saturday in portions of the Ozarks.

There are good signals for decent rain development. In fact, the water equivalent for the upcoming two storms will probably exceed one inch.  This will further knock down our drought condition for sure.

A backlash of snow is possible in say western Missouri late Saturday and early Sunday as this system departs.

 

 

Feb 262013
 

Pre-Dawn Snow in Clinton (Adam McMullin)

Snow is piling up in the Ozarks!

As of 6 am. there are numerous reports of 4″+of snow in areas just north of Springfield including Polk, Dade and Webster Counties.  Around the Lake of the Ozarks area, 4-6″ seems to describe it well.  Cole Camp in northern Benton County is close to 10″!

The National Weather Service measured 2″ at the airport in Springfield.

Lessor amounts included 2″ in Kimberling City and about a half inch in Gravette in Benton County, Arkansas.

It’s still snowing in these areas and will for several more hours. The rates of snow suggest another inch or two is possible adding to what has already fallen as slightly heavier snow bands rotate through the area.

Snow Reports as of 6 a.m.

Snow Bands on Radar at 6:10 am

Feb 252013
 

Snow Vs. Rain

A system coming out of the southwest will spread a band of rain across most of the Ozarks this afternoon with snow expected for many later tonight.

Rain Today

Rain showers will start breaking out by late morning over some areas with a main surge of rain expected in a line through the afternoon hours.

Snow Areas

The northwestern edge of this rain area will change to snow by this evening in western Missouri.  This trend will continue overnight spreading about 1-4″ of snow across areas northwest and west of Springfield.

Then by the morning and afternoon hours of Tuesday, a backlash area of snow will roll through the Ozarks, pushing the snow line more to the south and east.  This area will add another 1-3″ of snow, some on areas hit by the overnight snow and some in areas yet to receive it.

I included two maps estimating rain vs. snow areas for two different times.

Total Storm Snowfall

Total snow accumulations will reach over six inches in portions of St. Clair, Benton, Cedar and Vernon Counties by tomorrow afternoon. The storm is forecast to dump as much as 10″ of snow around Kansas City and a band exceeding one foot could occur between Clinton and Kansas!

Cold Week

It will be a chilly week ahead with highs only in the thirties and lows in the teens on some mornings!

Feb 242013
 

Another Winter Storm

This will be a pretty nice and mild Sunday even as projections place another winter storm in a portion of the Ozarks by late Monday.

Mild Sunday

Overall, a warmer day is expected in the Ozarks today.  Seasonal norms have climbed since their bottom out back in January with a low/high range now around 29/51. High temperatures will be very close to this mark today.  I expect a lot of sunshine to go with this.

Monday/Tuesday Storm

First off, Kansas City will appears to be on track to add at least another 6″ to their winter snow total!  The heaviest snow band is projected from northwest Oklahoma, into south-central and eastern Kansas and on into central and northern Missouri.  This all happens Monday evening into Tuesday morning.

As for the Ozarks, snow will range from nothing in northern Arkansas to perhaps near 6″ in Benton County Missouri and areas nearby.

I’ve got Springfield on a 1-2″ snow track with totals ramping up the more north you head.

Snow Projection Monday Night/Tuesday

Travel north to Kansas City or west to Wichita will be a mess Tuesday morning!

This again will begin late Monday evening and last into the overnight hours.

Colder Trend

All of next week looks chilly!  All high temperatures will stay in the thirties during the week.

Feb 232013
 

Winter Storm Watch Area for Monday

The weather system I mentioned as a rain/snow maker yesterday has perked up and appears to be on a more southern track for Monday.

Snow Maker

Monday’s system is now a potential winter storm. The enclosed map of the winter storm watch shows much of eastern/central Kansas and northern Oklahoma in the outlook area for snow.

What this means for the Ozarks is a possible snow accumulation now for some areas on Monday night/Tuesday morning!

The enclosed map shows one scenario for late Monday with the position of the low and snow areas (in blue).

This will start out as rain in the Ozarks on Monday afternoon.

Computer Model Forecast for 3 a.m. Tuesday Morning

Something to monitor now for sure!

This Weekend

It’s a fairly chilly morning over the Ozarks with widespread teens reported at 7 a.m.

Saturday will be on the chilly side for the season as the high temperatures stays in the thirties.

Sunday however will be closer to seasonal norms as the thermometer peaks up into the lower fifties.

Colder Week

The final week of February and the very beginning of March will be averaging much colder in our area. Get ready for many high temperatures only in the thirties!

Feb 212013
 

Snapshot Around 11:30 a.m.

Areas east of Springfield still have some shots of sleet and ice accumulation possible, a back edge to the worst of it is in sight!

The Storm So Far

We have had reports of up to .25″ of ice (not sleet) on some surfaces.  But a lot of what fell changed into sleet.  The reason for this had to do with the unstable air existing over the cold air at the surface. This lead to more convection (hence the lightning and thunder) which features rapidly rising air. This air cools as it rises, it converts a freezing rain layer into a sleet layer. This cut down on a lot of potential ice accumulation!

Small Hail in Willard (Austin Houp)

To complicate matters, some small hail was also included in some of the thunderstorms!  I enclosed a picture from Willard today of some pea-sized hail.

Hail looks smoother while sleet is more grainy.

Another tenth of on inch of ice accumulation is possible with the band of showers east of Springfield over the next few hours. Sleet will be mixed with much of this.

As for Springfield, stick a fork in it, we’re essentially done with the heavy stuff!

Feb 212013
 

Radar/Temperatures at 7 a.m.

Overnight, a wave of lighter snow and sleet moved north over the Ozarks.

At this hour, convective bands (with some lightning and thunder) are organizing over northwest Arkansas and southwest Missouri. This represents heavier precipitation rates and with temperatures in the upper twenties, freezing rain and ice accumulation will continue for a few hours.

There might be sleet in the core of some of the heavier bands, reducing ice accumulations somewhat but overall, expect conditions to worsen through mid-morning, especially north and east of Springfield.

The real question for the day is: how much warming will occur at the surface and where?  My belief is that Springfield will see a recovery to near 32 degrees, still icy but more manageable.

Winter Advisories

The concern all along has been the persistent below freezing situation which will set up for areas of northern Arkansas and perhaps south-central Missouri later this morning and afternoon.  An ice storm warning is still in affect for a portion of that area.

Icy Table/Deck in Lakeview, AR (Erica Schultz)

Feb 202013
 

Possible Precipitation Type at 9 a.m. Thursday

Everything is progressing at about the same pace as this morning’s forecast.

One exception is the development of a light snow band out ahead of the main band expected later this evening.  This has produced some minor accumulations in portions of Barry, McDonald and Stone Counties in Missouri and Boone County in Arkansas.  It will remain light and weaken as it moves northeast.

The main show is still tonight and Thursday. Remember that many, including folks in Springfield, will go through a progression of precipitation types. It will start as snow later this evening, change over to sleet late tonight and then go to freezing rain by Thursday morning.

So waking up in Springfield, there will be several inches of snow/sleet on the ground with a glaze of ice on top of that.  Some icing of trees and wires will occur in Springfield however I don’t believe we will see the worst of it.

The heaviest icing should occur over areas of north-central Arkansas and south-central Missouri. I still feel as if coatings of near .40″ of an inch of ice are possible in these areas by tomorrow afternoon.

Pure snow accumulations will be reserved for areas about an hour north drive from Springfield during this storm.

I will have more updates later today.  This will include my video blog and a live web show at 6 p.m.

 

Feb 202013
 

Main Precipitation Threat Tonight/Thursday

All of the Ozarks are under some short of winter storm warning this morning for later tonight and Thursday. Ice accumulation is still a concern.

A huge amount of humidity is being lifted over a dome of cold air which will result in lots of rain aloft, which will transition to a mess in the Ozarks on the ground in the form of sleet and freezing rain.

Layout of Precipitation

There is an expected transition of precipitation type for many in the Ozarks. When the initial wave comes in tonight, it’s expected to be snow and some sleet.  This will probably stay snow in areas from let’s say Lamar to Camdenton northward.

As for Springfield, snow will give way to sleet and eventually freezing rain (ice) by dawn on Thursday.

Freezing Rain vs. Sleet: What’s the Difference?

 

Areas of northern Arkansas and south-central Missouri will hold on to freezing rain the longest and have the biggest threat of significant ice accumulations.

Totals

I expect Springfield will see several inches of snow/sleet overnight tonight with a glaze of ice on top of that starting sometime in the early morning hours of Thursday.

The snow up north could amount to 1-3″.  This of course will become a major snowstorm north and northwest of the Ozarks.

Ice accumulations will be between .10 and .40″ I think with the higher amounts in the area specified on the graphic.

Information Today/Tonight

I will post a winter storm update after the morning computer model runs come out, right around noon.

I will post a video review/blog by late afternoon.

Also, look for a live web show tonight to discuss the situation. Details coming up later today!

Feb 192013
 

Winter Precipitation Depends on Temperatures Above

When I use the phrase “winter mix”, it refers to some combination of snow, sleet or freezing rain (ice).

The term is used whenever any of these are possible over a certain time frame.

Both sleet and freezing rain require a layer of above freezing air aloft.  The difference is in the depth of the sub-freezing layer touching the ground (lower blue areas on diagram)

While the “general” layout is for snow to occur closest to the colder air with sleet, freezing rain and rain occurring in bands toward the warmer air (usually in a southerly direction), there are exceptions.

One is terrain. An increase in elevation means colder temperatures which can change the precipitation type.  Or the opposite, occasionally cold air becomes trapped in valleys and alters precipitation type.

Also, convective (rain/thunder) bands tend to cool a column of air near the ground and turning what might be a freezing rain situation into sleet.

Here are the definitions:

Sleet

This is liquid (rain) aloft which falls into subfreezing air near the surface deep enough to freeze the drops into ice balls.  Sleet “tings” when it strikes windows.  Sleet accumulates like snow but because it is essentially little ice pellets, it doesn’t accumulate nearly as fast. It actually offers some increased traction on roads when compared to snow.

Freezing Rain (Ice)

Nearly the same as sleet except that the drops stay liquid falling into a much shallower subfreezing layer at the ground. These “super-cooled” rain drops will then freeze on contact with surface objects, especially those off the ground such as trees and wires.  Freezing rain producing ice accumulations over a half inch can cause branches and wires to snap from the weight. An ice storm is born!