Tuesday, December 03, 2013

A Winter Storm Is Brewing


12:15 PM Tuesday Update... No rest for the weary huh?  I want to first explain the SCHOOL:CON index you saw on twitter and facebook.  I fully believe in giving credit where credit is due.  If someone comes up with an idea, I acknowledge that.  Yesterday (Monday), I was sitting in the Channel 7 weather center talking to Scott Inman.  I don't know how exactly it got brought up, but he mentioned The Weather Channel's TOR:CON index and it somehow morphed into the SCHOOL:CON index.  Thanks Scott!

What does it mean though?  It's very simple.  On a scale of 1-10, how bad will the weather become.  10 means school will be canceled and 0 means it won't be canceled.  So if your area has a 6, it simply means, IN MY OPINION,  there's a 60% chance you will not have school.  PLEASE REMEMBER, I DON'T MAKE THOSE DECISIONS.  THAT'S LEFT TO SCHOOL ADMINISTRATORS ACROSS THE STATE.  I will do my best to update the SCHOOL:CON each day.

Now onto the weather update.  I simply have no change.  I have warned you from several days ago about the error the model will most likely have.  This is why there's a good chance if you just read the models, your forecast will bust.  Arctic air is stronger and arrives faster 99 out of 100 times.  We see that in the modeling now.  The new GFS has a high in Little Rock Friday of 31 and a high Saturday of 30.  Guess what?  That may still be too warm.  Could it be warmer than this and it's a plain, cold rain?  Of course.  As I said in the blog post below, there's only one person who knows.  He's the best meteorologist ever.  The rest of us will not know until after it happens.  As of today, based on history and the model data, I would hedge my bets on a colder and icy forecast. 

I think our best case scenario in the metro is sleet.  YOU DO NOT WANT FREEZING RAIN.  However, the models still show significant amounts of freezing rain.  But like I said, if the cold air is stronger, there's at least a chance the precip will be in the form of sleet... A CHANCE.  Sleet is simply pellets of ice that bounce on the ground.  It does cause travel problems, but keeps trees and power lines from coming down.  Freezing rain builds a layer of ice on EVERYTHING.... VERY BAD.  Why ice?  This is a very shallow layer of cold air.  There will be a layer of warm air above it so any snow falling out of those clouds will melt in that layer.  As it falls in the subfreezing air, the question is:  does it freeze and form sleet or is it rain, then freezes on contact?  (Freezing Rain). 

Again, I have no changes.  I think a mix of sleet and freezing rain will work its way south out of north Arkansas Thursday night.  I think it arrives in the metro before sunrise Friday.  Read below for more information.  Remember, this forecast can and may change so stay with the blog, Ch. 7, social media, katv.com, etc.

One more thing, THANK YOU SO MUCH FOR COMING TO THE ARKANSAS WEATHER BLOG FOR YOUR INFORMATION.  It means a ton you do that!


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I don't have much in the way of changes from what I discussed in the previous posts and videos.  For those of you who read models, it's important to remember they are only computer generated.  You must take into account the real world and especially what history tells us.  Most of the time, arctic air masses tend to be stronger and faster than what most of the models predict.  Can this event be the exception?  Sure.  But, I'm going to stick to my gut instinct.  Being born and raised here in Arkansas and studying our weather since I was in grade school, I know how these things typically go down.

Anyway, I don't expect things to really go down hill until Thursday night in the metro.  Of course, there's always that chance it starts sooner and I'll monitor that for you.  The extended period of cold is still very much on the table and we'll have to watch for the possibility at some point next week for Little Rock to drop into the single digits one morning.  If that happens, it will be the first time since February of 1996.

This post will deal with the precipitation expected Wednesday night into Friday.  There will be a another round Saturday PM into Sunday and I'm worried about portions of central and south Arkansas with that one.  There will be the chance for more significant amounts of ice.  In my opinion, I'm not sold on the idea of snow here at that time.  Here are my PRELIMINARY MAPS.

The NW corner of the state around the Ozarks will hold up the subfreezing air for awhile and this is why the ice is expected there first.  It may take a few hours to dislodge that subfreezing air and move it south.  However, it will be turning cold across the remainder of the state, just not 32 degrees of colder.
Thursday night, the cold air is on the way southward.  The 32 degree line will be around Mena to near Little Rock to NE Arkansas.  Still a cold rain across the south.  The ice may change to snow across the NW at this time.
Friday may end up being the worst for much of the state.  I expect an icy mix of freezing rain and sleet through western, central, and NE Arkansas and amounts could be more than .25''. This amount or anything greater can cause big problems.  The southeast portions of the state will have a cold rain, but should change to freezing rain before ending.  Some problems may develop there, but not to the extent further north.  Snow up in the NW corner likely.
The GFS valid late Thursday afternoon shows the ice mixture moving south.  The peach is sleet, purple freezing rain, and the blue is snow.  The green is a cold rain.
By Friday morning at 6AM, there's a mix of freezing rain across much of the northern half of the state and maybe even further south.  The snow is falling across the NW.
By Friday afternoon, the precip. is exiting and the SE may transition to some icy weather before ending.
The NWS has issued a Winter Storm Watch for all the counties highlighted here Thursday night into Friday.  I expect some and maybe all of this area to be under an "ice storm warning" at some point.  Stay tuned
In summary, it's looking more and more likely a winter storm will affect a large portion of Arkansas and very cold temperatures will grip the state for an extended period of time.  As I always say, NOTHING IS ETCHED IN STONE UNTIL AFTER IT HAPPENS.  All I can tell you is that there's only one person who knows exactly what will happen.  He's the best meteorologist of all time and he's got a birthday coming up later this month!

6 comments:

Anonymous said...

Thanks for the great post Todd! Really enjoy reading them.

Mitchell McDill said...

I like the SCHOOL:CON index on Twitter that Todd put up. Does it use the complex algorithms like the TOR:CON? If we had only had this bit of technology when I was in school.

Denise said...

Thanks so much Todd! I am such a weather geek and I just found your blog. It has been great to check in on your latest post.

I work in the schools and can tell you that the students are like the squirrels, they sense a change in the weather and are bonkers today!

Anonymous said...

Why does the 7 day forecast say the high will be 42 next Tuesday if Todd says it will be "brutally cold" next week?

Anonymous said...

Todd,

A great post. And he does have a birthday coming up later this month. You are greatly appreciated.

Dan Cantrell

Anonymous said...

That was nice of you to say about Ned Perme. I don't know about best meteorologist ever but he's pretty good. ;)