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!

 

Feb 142012
 
Potential Storm Tracks

Monday’s much anticipated snow got better at accumulating as it travelled east. Some of the higher totals:

 Licking  5″
 Plato  4.5
 Vichy  4.0
 Rolla  4.0
 Mansfield  4.0
 Iberia  4.0
 Highlandville  3.8
 Monett  3.0
 Richland  3.0

Springfield measured 1.7″ officially with a season total of 2.8″, still pretty slim!

Springfield National Weather Service Summary

Back to Rain

The next weather system looks warmer which means rain for the Ozarks. In fact, there might be enough instability to support some lightning and thunder as it swings through on Wednesday. The winter side of this next weather maker will be far to the north. Northwest Missouri may get a swath of snow along with portions of Kansas.  The severe storms’ side of this next system will be from east Texas through the deep south into Arkansas, Louisiana, Mississippi and Alabama on Wednesday.

Storm Tracks

It’s interesting to watch potential storm tracks over the next week or so. So much so that I made a map showing their most likely tracks.  As of now, I don’t see any winter preciptation makers.  The only potential candidate would be the deep south weekend system.  Then there’s a hint at something the middle of next week (yellow). Stay connected…

 

 

 

 

 

 

Feb 132012
 

Snow Near A and 60, Webster Co. Credit: Paula Dean Little Wood

Today’s winter precipitation is unfolding pretty much as forecast.  I’m calling this our “speedbump snow”!

The band of snow moved in before sunrise.  Widespread totals of 1-2″ have be reported in the area with an occasional 3″ total. (Mansfield picked up just over 3″)  A viewer did also report 5 inches of snow near Norwood late this afternoon.

Snow is pretty much confined to areas east of Springfield and still coming down pretty good in some of those areas.  This will slowly wind down this afternoon and early evening.

Some warmer air aloft has changed the snow over to sleet or light freezing rain at times in areas from Springfield west.

Temperatures at the surface have warmed to around freezing in western Missouri and Arkansas. Readings will hover where they are or perhaps even rise a degree or two into the early evening hours.

I don’t believe the freezing rain or drizzle poses an additional travel problem. Arctic air is not poised to come slamming in here tonight and instantly freeze everything.  Temperature will be just below freezing however and drivers should take it easy of course.

Feb 132012
 

About 3/4" at 7am in Springfield

The snow has arrived!

This snow system has behaved itself quite nicely thus far.  It has initially run  into some very dry air so the snpw start time and totals so far have been somewhat hindered.

One inch snow totals are very common through about 6:30 am this Monday morning including Mtn. Home AR and Springfield.  The snow is sticking to area roadways.

Now that the air has been primed with higher humidity by this first snow batch, additional snow later today will be somewhat more efficient when it falls.  A forecast of 1-3″ storm total still looks just about right for the area.

Later today and this evening, a changeover to freezing drizzle is expected.  Since this is light precipitation, ice accumulations will be very light.

Oh, also, the Springfield National Weather Service radar is down for an upgrade in case anyone trying to access radar images on-line is wondering.

 

Feb 122012
 

Slick Conditions Monday AM

Upstream

I will be doing a live web show talking about our upcoming winter precipitation tonight at 7 pm.  The show is called “Upstream” and it will feature more “geeked out” weather explanations and computer model data.  There is a live chat connected to it as well for folks to ask questions.

The link is on this website and can be viewed here

Winter Precipitation

As you can see, the winter weather advisories have been expanded to include just about all of the Ozarks, eastern Kansas and a large chuck of Oklahoma.

Much of the initial snow aloft will be falling into dry air therefore it will take a bit to start reaching the ground tonight despite the way it may initially look on weather radar.

This will be overcome throughout the morning hours on Monday and I think light snow will start in Springfield around 4 am, give or take an hour or so.  Some of this precipitation will be mixed with sleet especially west and southwest of Springfield.  Sleet generally has the effect of reducing snow totals (it’s not fluffy!)

Totals of 1-2″ inches are expected over a broad area of the Ozarks.  Note that Newton County AR (and counties just to the south) is under a winter storm warning. These elevated areas may see enhanced precipitation totals of up to four inches.

A transition to light freezing precipitation will happen gradually on Monday afternoon.  The type of precipitation is regulated mostly by what happens aloft.  Some of the ice crystals needed for snow may start to disappear which would leave us with freezing drizzle. The jury is still out on exactly when or if this will take place.  One morning model keeps Springfield in light snow throughout much of the day but the temperature profile is so close that a mixture would be the best way to describe it.

 

 

Feb 112012
 
Probability of Snow >4″

Two things:

1) There is a Winter Storm Watch in effect for a portion of the Ozarks. Winter Weather Advisories will likely be in effect by Sunday night.

2) My web show “Upstream” will come back for special weather events!  Expect an installment on Sunday evening at 7 pm.  This can be found on this web site now (not Ceaseless Wind).

If you don’t know, “Upstream” is a special look at weather, kind of “behind the scenes” if you will, which will feature more detail then you can get on T.V. or in blogs.  You can also chat live!  I will provide “linkage” on Sunday.  I did this show daily about two years ago.

A Winter Storm!

Well, this is different!  With our season snowfall total practically non-existent at 1.1″, we have a chance to quadruple it by Monday afternoon.

Actually, I think totals of 4″ will be the exception rather than the rule!. Widespread 1-3″ totals seem a bit more plausible.

Late night model runs are hinting at a later start to the snow, say closer to 6-7 am Monday morning. It has been trending this way during the day.