Wednesday, February 13, 2013

BIG Temperature Roller Coaster and More Storms Next Week.

9AM Wednesday Update... Harrison had 1'' of snow last night so their seasonal total is up to 1.3''.  This brings the total between Harrison, Hot Springs, Little Rock, and North Little Rock up to 30.6''.  At this time, Jerry and Terry Morrison are atop the leaders board in this years winter weather contest.  We have until the end of this month so this can still change!


Get ready for a major temperature swing starting Friday into next week.  There is one heck of a trough that will swing through the central portion of the country, but it will not stick around.  I still can't understand why the GFS MOS still has temperatures in the 50s Friday and Saturday?  When you look at the trough and the cold air advection starting Friday morning, you would think highs will only reach the 30s with wind chill readings in the teens and 20s.  I guess we'll see who gets this forecast... the computers or me?  The GFS run Tuesday night shows a high Friday of 52 and a high Saturday of 53.  The only way we hit 52 on Friday is early in the day and temperatures would likely fall back into the 40s.  

I'm really focusing in on Saturday because I think there will be 3 factors holding temperatures almost 15 degrees or more below the GFS forecast: cold air advection, clouds, and... wait for it... wait for it... wait for it.... SNOW.  Did that get your attention?  It's only light snow or flurries!!  Probably not a big deal whatsoever, but another reminder winter will not go away yet.

Like I said, this cold air mass will not stick around as the arctic high will move east allowing a significant return flow to set up.  This the up side of the roller coaster.  By Sunday and Monday, there's a possibility temperatures go back ABOVE average!  What a swing if that happens!  We also have the possibility for 2 significant storm systems next week.  How will that affect Arkansas?  I'm going to be completely honest with you, we just don't know yet.  It's all depending on the track of each storm.  The possibilities include just plain ole rain, thunderstorms, or even wintry weather.  It could also be a combination of all three.

So like I said, get ready for some interesting weather over the next 7-10 days.  We're going to earn our pay!  The maps below explain it all....

This is the Euro valid at noon Saturday.  Look at the 40 degree isotherm running through all of central Arkansas.  Everyone north of that line is in the 30s.  I can't see going from the 30s at noon to a high of 53 like the GFS says with clouds and what I'll show you below.
This is the Euro valid at noon as well.  Look at that grey area of Arkansas.  That's very light snow or flurries produced by a wave of energy aloft.  How do I  know that will be snow if temperatures are above freezing at the surface?  Look at the rain snow line (540 line in blue). That's all the way into the Gulf!!!!!!!  The conditions aloft are super cold and whatever falls will be frozen.  See the black closed line to the west of the state?  That's the center of arctic high pressure.  With the clockwise flow out of that high, we are seeing breezy conditions out of the north pumping in that cold air.  That high will quickly move east allowing a return flow on the back side and the warm up begins.
This is the Euro at noon Monday.  Readings are back into the 40s and 50s across the state.  Look at that air lurking to our southwest in Texas... 60s and 70s!!!!!  Also, look at the air over the northern plains.. below 0!!!  Here we go with another front and wave of low pressure and a major clash of air masses.  How that unfolds is still a question.
This is late Monday and we have another wave of low pressure and more rain.   Taking this model literally, this is just rain and a few rumbles of thunder, but a changeover to more wintry weather is possible just to our NW over Oklahoma into Missouri.
And here we go AGAIN next Thursday.  A strong wave of low pressure brings rain and storms to the state.  This taken literally indicates a major snowstorm over the plains.  Again, this will change and the details are yet to be sorted out.  The data will not be able to pinpoint an exact track of the low this far out!
In summary, there's a lot of weather over the next 7-10 days.  We know there will be a blast of cold air for a couple of days Friday and Saturday and we know there will be more storm systems to watch next week.  Right now, it looks like soakers, but we must watch the track of these systems along with their intensity.  We are watching winter and spring battling it out!

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NOAA Winter Guidance