Monday, November 10, 2014

A November To Remember As Arctic Air Attacks



Every time I look at the models, I'm in absolute awe.  Usually we get cold air in November, but it's in and out.  This is so strong and lasts so long making it truly amazing.  Watch Christmas be around 90 degrees.  LOL. I hope not!  The jet stream is undergoing major amplification and it stays amplified for at least the next 1 to 2 weeks.  This simply means there are large ridges which poke up into the higher latitudes and troughs which dip well south.  The ridge going up into Alaska and the arctic will be able to dislodge the cold air and send it south for most locations east of the Rockies.

Is this record cold? Maybe.  I don't think we'll break any daily record lows.  Clouds and wind will keep overnight lows from really dropping off a cliff.   However, with cold air in place, clouds and wind will help hold down daily high temperatures and I would not be surprised if we broke a record or two for coldest daily high temperature.  Over the next week, those are mostly in the mid 30s.

There are also signs even colder air will visit the state next week.  With a stronger push seen on most of the models, there's also one other variable which could make it even colder than this week.  The snow cover across the plains north of the state is lacking right now.  As the arctic air moves south, it will moderate.  However, next week, there should be expansive snow on the ground north of the state which will keep this air "refrigerated" as it plunges south.  So while we have highs in the 40s this week, starting Wednesday, I would not be surprised if it was even colder next week.

What about winter precipitation?  I remember meteorologist Barry Brandt saying, "with arctic air in place, anything can happen".  That's the truth!  I have already talked about next Saturday into Sunday.  The GFS really doesn't show much moisture, but the Euro does.  My gut tells me this will be a very fast moving system and any precipitation with it will be light.  In other words, I'm not sold on the weekend event.  I think most of us COULD see a few cold rain showers, but it's northern Arkansas which has a small chance for some light sleet/snow.  This is what I call a "high impact forecast" due to the Razorback game in Fayetteville... or should we call it "Fayette-CHILL"?   We want everyone to stay safe so it's something we're really going to watch.  According to various sources, it has not snowed at a Razorback game since October 30th, 1993.  So it's possible this will be the first time in more than 20 years.  Hey Les Miles, welcome to Ar-Kansas.  LOL.  Remember that?  

Check out the following maps below and most are courtesy of weatherbell.com

The NAM at 9AM Tuesday morning.  The front is easily seen.  Temperatures are near freezing across the NW to 60s south.
This is the forecast total snowfall from the European model by this Wednesday morning.  The air coming down the plains will have the ability to moderate a bit due to the lack of an expansive snow field.
1 week later, look at the major increase in the snow cover.  PLEASE, DO NOT TAKE THIS MAP LITERALLY.  I know you see the snowfall accumulation over Arkansas.  IT'S VERY UNLIKELY TO VERIFY!!!!!!!!  The only reason I'm posting this is to show you the increase in snow cover from this week to the next.  As the air comes over that snowpack, it will stay "refrigerated" and it could be colder next week.  Again, please remember not to take this literally.  I feel if there's any accumulation, it would be across the north, but we're watching it of course.
Highs Wednesday range from the 30s north to 40s elsewhere.
Thursday could be even colder with highs barely getting into the low 40s for central Arkansas.
Highs Saturday look even colder with 30s for the west and the north.
Highs Sunday could only be in the upper 30s according to the European model.
Highs Monday only in the mid 30s?????  It's a week away, but it makes sense.  With more cold air coming down and more snow on the ground north of the state, this is possible.
Now onto the precip. chances this weekend.  This is valid at midnight Sunday.  Check out the European model above.  It's much wetter compared to the GFS. Remember I said my gut tells me this will be lighter and faster moving.  The blue line is called the "540 line".  It's a good indicator as to where the rain/snow line may set up.  I also suspect, some light sleet will also be possible.  Further south, it's just a cold rain.
The GFS shows the moisture, but it's lighter and faster moving.  There are some differences between those models, but as I said, I feel this will be light and quick moving.  HOWEVER, it's several days away and I'm watching it closely.
The cold will hold.  NOAA's 6-10 day outlook (November 15-19) shows a high chance for well below average temperatures.  Notice how Alaska is above average.  This is very typical as the warm ridge builds along the west coast into Alaska and send the cold air south, especially for areas east of the Rockies.
NOAA's 8-14 day outloook (November 17-23) shows the same thing.  Like I said, typically cold air is in and out this time of year.  This is going to stick around for 1-2 weeks at least.

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NOAA Winter Guidance