Tuesday, February 12, 2013

Winter's Back! Snowfall To Track.


1PM Tuesday Update...  I have no changes to what I think will happen tonight into  Wednesday morning.  Read more about that below if you haven't yet.

The new run of the GFS continues to have our high in Little Rock Saturday around 50 degrees.  I can't believe that for one second.  I would not be surprised if it was 15 degrees cooler for a high.  Again, nothing we haven't seen already, but I sense a big model bust.  The new Euro is out and it brings a shot of flurries and show showers in Saturday morning and afternoon.  Its surface temperatures are cooler, but I still don't think it's cold enough.  The blast of late week cold will not hold.  I suspect the cold air mass will dig in and move out quickly.  The Euro has 3 systems over the next 10 days. I will focus on each with a new post soon.  This is including the weekend flurries.  

This is the Euro surface temperature at noon Saturday.  The 40 degree isotherm is well south of Little Rock which means it's in the 30s for most of the state.  I think this has a much better handle on the quick shot of cold air this weekend.  Winds should be strong too.  So as I have been saying, I think there's a good chance highs will not get out of the 30s Saturday with wind chill readings in the teens and 20s with a few snow flurries or snow showers.  The GFS says 50 degrees.  We'll see who wins this battle, but I am firmly siding with the European model!

I still have no big changes to what will happen tonight and into Wednesday morning.  Looking at the dynamics of this system and looking at the morning radar, I think it's entirely possible far northwest Arkansas could see a little "thundersnow".  While snowfall amounts will range around 1-3'' there, I would not be surprised to see 1 or 2 spots in the higher elevations come in with a little more than that.  As I have been saying, this system has NO arctic air to work with so it must bring its own cold air with the upper level low.  This unstable portion of the storm will generate enough lift to cool the atmosphere enough to bring snow down to the surface in northwest Arkansas.  This will be one of those heavy, wet snowfalls.... good for snowballs and snowmen.  SEND PICTURES TO PHOTO@KATV.COM

As for central Arkansas, yes, I do think we could see some snowflakes Wednesday morning, but accumulations will be little if any.

In the previous blog post, I talked about the snow possibilities for Friday night into Saturday morning.  I did NOT believe the GFS output calling for significant snow.  As of this Tuesday morning, the GFS has trended towards the drier Euro.  I think a round of snow flurries or quick snow showers will still be possible, but that's it.  If that changes, I'll let you know.  I still don't see why the GFS still has highs near 50 Saturday.  I just don't buy that.  Remember, we're going to watch to see if this model knows what it's doing.  I suspect it will be 10-15 degrees off.  Highs Saturday may not get out of the 30s with wind chill readings in the teens and 20s.  This will be a cold air mass which will move in and out rapidly and has NO staying power.  There are signs of more storm systems the following week to track, but how they impact our weather is not yet known.

Below you will find our interactive radar with LIVE streaming video from "snow chasers" in the southern plains.  Watch the snow live and track it here!  Just click on the flashing cars and the live video will pop out.

Also below are maps from the various computer model outputs dealing with snowfall accumulations.

This is the newest GFS output showing 1-3 and maybe 4'' for northwest Arkansas.  Look at that area of accumulation from near Little Rock over to Memphis along I-40.  That's a little suspicious to me and I'm not buying that right now, but we will watch it!!!!  It appears everything is lining up for the main axis of snow from Amarillo, TX to Springfield, MO eastward.
The NAM only indicates the Ozarks getting snowfall
And here is the Euro.   This is troubling to a forecaster because this model has been outstanding this winter.  It shows NOTHING!!!!!!!  This is more than likely due to the warmer surface temperatures expected.
HPC shows a high likelihood of at least 1'' of snow in those higher elevations.

No comments:

NOAA Winter Guidance