Tuesday, November 11, 2014

It's Only Going To Get Colder



This is only the start of what will be remembered as a brutally cold November.  I'm becoming more and more convinced of that.  While the remainder of this week will be cold, I think next week has the potential to be even colder.  I outlined my reasons in the previous blog post.  First, the pattern continues to stay very amplified with even stronger shots of cold air.  Second, the air will travel across larger snow fields to the north and that should keep it colder as it plunges south.

With this first taste of winter comes possible records.  While I have doubts about hitting daily record lows due to wind and clouds at night, we must also watch records for coldest high temperatures.  Here are the records starting Thursday for the next week.

                                                   RECORD LOW            RECORD LOW HIGH TEMPERATURE.

Thursday November 13th         20 (1986)                         34 (1986)        
Friday November 14th              22 (1986,1969,1940)       32 (1986)
Saturday November 15th          20 (1969,1940)                36 (1959,1940)       
Sunday November 16th            23 (1940,1920)                38 (1889)
Monday November 17th           20 (1959)                         34 (1959)
Tuesday November 18th           10 (1880)                         30 (1880)
Wednesday November 19th      12 (1880)                         36 (1880)

The forecast this weekend is yet another challenge and it's what I call a "high impact forecast" due to the thousands attending the Razorback game in what I'm now calling "Fayette-Chill".  I strongly feel temperatures will start out in the lower 30s at kick-off and end in the 20s.  It's even possible for the entire game to be played with readings below freezing.  Wind chill temperatures will be in the 20s.  What about precipitation?  Yes, there's a chance.  There's conflicting model data and I'm still holding onto my forecast that anything that falls will be light and fast moving.  It looks like cold rain showers around central and southern Arkansas, but a mix or light snow COULD fall up north.   

The GFS (Global Forecast System) just got an upgrade and it now has a higher resolution which theoretically should make its forecast guidance better.  However, it's still in beta testing.  This higher res has been showing more moisture with the disturbance and new cold front pushing through later Saturday into Sunday.  The European model also shows more moisture.  However, the operational GFS shows little if any precipitation.  Once again, I'm not completely sold on this event, but I do think there will be at least some wintry weather in the state this weekend with the best chance up north.

The early Tuesday run of the Euro shows significant moisture across the state Saturday afternoon and evening.  The solid blue line is usually a good indicator of the rain show line.  Notice the closed back circle over Iowa, that's a surface low and a trailing front into Oklahoma.  See the black closed line over Wyoming?  That's a new area of surface high pressure.   That will re-enforce the cold air and probably make it even colder to start next week.  This model is showing mostly a cold rain for central and southern Arkansas with a possible wintry mix north.
Forecast surface temperatures from the Euro late Saturday.  The solid white line is the 32 degree line so this is saying the best chance for any frozen precip. will be north west and north central Arkansas with a cold rain elsewhere.
A close up look using the Euro from weatherbell.com shows this as well.  The dark blue line is the 32 degree line at 6PM running through northern Arkansas.  The lighter blue line is the 35 degree line.  This is saying we are likely between 35 and 40 degrees here in central and southern Arkansas. 
The new higher res GFS  shows a colder and snowier scenario late Saturday.  I'm NOT buying this at this time.  Just because the resolution is higher doesn't mean this will beat other models.
The operational GFS late Saturday doesn't show much moisture at all, except a few light snow showers across the north.

In summary, the cold is bold and it's going to hold!  That's the big weather story for at least the next 1-2 weeks.  Watch for next week to be even colder than this week.

As far as winter weather chances this weekend are concerned, I suspect at least a few flakes will fall across the north.  All the guidance shows that, however, how much moisture?  The Euro and New GFS seem to show the higher moisture amounts.  The GFS is getting this upgrade in order for it to compete with the superior European model.  I suspect the answer COULD be somewhere in between.  As I said, I think this is light and quick moving with a few cold rain showers around the state and a possible mix up north.  Then there's always the operational GFS which doesn't show much at all.  As we get closer, we'll be able to fine tune this forecast.   Stay tuned!

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NOAA Winter Guidance