Thursday, January 02, 2014

Extreme Cold, Snow, and Ice All Take Aim On Arkansas


Once again there's so much to discuss in the long range, I keep asking myself "where do I begin?"  Yesterday (Wednesday), we first discussed the possibility for not 1, but 2 episodes of wintry weather.  The first arrives Sunday as a wave of low pressure develops along the arctic boundary. This should bring rain changing to snow Sunday, especially across northern Arkansas.  The big weather story will then turn to the very cold air which engulfs the region, including Arkansas.

Remember in the video I talked about the retreating arctic air next Wednesday and a moisture plume moving northward out of the Gulf?  Once again the models are indicating that scenario.  Usually arctic air is tougher to dislodge than the models suggest. Here's why.  Arctic air is very heavy like a brick.  Try moving that brick with the force of a garden hose (the Gulf moisture).  The warm, moist air from the Gulf usually begins to override the dense cold air at the surface and this produces clouds and precipitation.  The time it takes to scour out the arctic air is usually slower than the models indicate.  Also, due to the warming aloft and the cold air at the surface, ice can become a problem.  While this is still in the long range, it must be watched carefully.

HERE'S WHAT I'M ASKING YOU TO THINK ABOUT OVER THE NEXT WEEK: PETS, PIPES, AND PEOPLE!  This type of cold will take its toll on all three!   Also, with the cold weather today (Thursday) and into Friday, then the plunge of colder air next week, small ponds will begin to freeze over.  They will be very tempting for kids to play on.  DO YOUR BEST TO KEEP THEM OFF.  Knowing the thickness of that ice is very difficult and it may be easy to fall in.  It can become a deadly situation.  A similar outbreak of arctic air happened years and years ago and this became a problem.  Let's do our best to keep the kiddos safe too!

Check out the model maps below from weatherbell.com

Here is the GFS interpretation valid Sunday morning.  See the black closed line over the Delta?  That's a wave of low pressure along the arctic boundary.  You have rain changing to snow and ice on the back side of it as the bitterly cold air sweeps into the state.

The Euro shows accumulations over the northern half of the state.  Minor amounts in central Arkansas, but 1-3'' could fall across the far north.  I'm only telling you what the model is indicating and not making this a forecast just yet, but this does seem reasonable given the set up.

The GFS wind chill forecast Monday morning shows readings well below zero for the northern 1/3 of the state.  This may warrant a WIND CHILL ADVISORY.

The cold air coming next week looks very strong.  The Euro Monday morning shows readings well into the teens here in central and southern Arkansas with single digits up north.  The greens and whites are readings below zero over Missouri.  The Euro sees the snowpack and is dropping temperatures significantly there.  I wrote a blog post a couple days ago about the Euro doing this with too much cooling but this actually could be reasonable given the set up.  Nevertheless, I think single digits and teens will be possible over a large chunk of Arkansas, BUT that's not the big story, IT'S THE WIND!!!


Tuesday morning temperatures will continue to be very cold with lows in the single digits and teens.
Now onto the next weathermaker.  This is late Wednesday and the arctic high is retreating to the east.  The return flow will send Gulf moisture on top of this cold air at the surface.  Look at those temperatures in the 20s still by 6PM Wednesday.  This is a situation where temperatures Wednesday morning could start out in the low to mid 20s and rise all day long and get to around 30 at sunset AND it keeps rising at night due to the warm air advecting in.  This could be a slow process of getting us back above freezing.  In the meantime, ice COULD become a problem.
And the GFS agrees with the above Euro.  The high is off the map to the northeast with an easterly to southeasterly flow.  The red line is the 32 degree line Wednesday at 6PM.  The blue is the snow, the orange is sleet, and the purple is freezing rain.  See my concern about next Wednesday?
The GFS SLOWLY warms temperatures up next Wednesday night into Thursday morning, but keeps us mostly below freezing.  The red line is located across southern Arkansas.  Everyone north of it will be below freezing.  The air above has warmed enough that whatever falls is freezing rain at the surface....ACCORDING TO THE GFS.  Due to this in the long range, it can't be taken literally yet!!!  The speed of the warm air coming in from the south and the amounts of moisture are still big question marks at this point!

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