Sunday, January 28, 2018

Winter Punches Back

We still have plenty of time for winter to punch back and punch back hard.  However, what's coming at the end of the week is just a little jab.  

The January thaw has been noticeable and strong when compared to where we were from Christmas to around mid-January.  We had a break with even some severe weather (4 tornadoes), and now we are going into a more active and potentially colder pattern.

The developing pattern screams cold, but the models are getting cold feet with each run.  I'm referring to the week of February 4th.  I know, I'm getting ahead of myself.  I don't think anyone can expect the models to have a full grasp on what happens as we head deeper into February.   However, with a ridge going up into Alaska and the arctic circle, I think it will be quite easy for the cold to push south.  I just don't know at this time the furthest extent to the south.  This will also help determine where the active and potentially stormy pattern evolves.  More on that later.

The weather this week looks quiet through Wednesday, then a strong front will move through the state with a cold RAIN!!!  Yes, rain.  The question remains, how much moisture remains by the time to coldest air arrives.  The models offer varying solutions.  The Euro has a brief changeover across northern and northeastern Arkansas while the GFS shows a longer changeover and a more expansive one covering the northern 1/2 of the state.  As much as I want to believe the GFS, I can't.  However, it does have support from the operational Canadian.  Nevertheless, I think when things are said and done, it will look more like the Euro.

Are we talking big snow or just some "flakeage"?  I just made that word up.  Anyway, I don't see this being a big one whatsoever.  The ground temps have recovered so IF there is any accumulation, it would mainly be on grassy and elevated surfaces and it would be light.

This being Sunday, things can always change and that's what we are here for.

Late Thursday, the cold is here and the moisture is leaving.  However, there is a chance for a brief change to snow or rain/snow mix north and northeast Arkansas according to the newest version of the Euro.

The GFS brings the rain and snow mix further south into portions of central Arkansas late Thursday into early Friday.  While I don't believe it will look like this at this time, all amounts would be light.

Only a model! NOT a forecast.  The Euro snow amounts are negligible.

GFS snow amounts are more for obvious reasons.

NOAA 8-14 day guidance.  THESE ARE NOT FORECASTS!!!!!  This simply shows you where the confidence for average, below average, and above average temperatures exist.  When Alaska goes above average, look out!  I find it humorous when we get cold, Alaska warms up and some think it's a weird weather phenomena.  No, It's very normal.  It's how we get cold in the south.  That cold air gets dislodged and moves south.  It's only natural they warm up relative to average.  There's something you really need to notice with this map though.  Look at the area across the mid-south to the southeast.  Notice how you go from below to above over a short distance.  There will be a zone of great temperature variance and this is where the storm track will likely be found.  If the jet and the surface front is suppressed south, we're looking at winter weather chances.  If it's further north, rain and storms.

And the precip outlook in the 8-14 day time period shows where that storm track will likely exist with a good chance for above average precip from Texas to the middle Atlantic.

From  This is the Global Ensemble Forecasting System 500mb GPH anomalies.  I would like to show you the Euro Ensembles, but it's prohibited.  Sorry. However, the GEFS is similar.  In short, look at the reds (ridging) into Alaska the week of February 4th.  You can also see the vortex spinning across Hudson Bay.  The Alaskan/arctic ridging and downstream trough is a perfect set up to deliver multiple punches of cold air. You can clearly see the flat ridging over Cuba and the Bahamas.  The cold air will be low level and will meet resistance.  Where that zone sets up will likely be from Texas into the middle Atlantic.  I don't expect the models to ever have a good handle on the location and extent of arctic air.  However, 999 out of 1000 times, it underestimates it so it will be fun to watch.

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