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John1122

1/5/17-1/8/17 Southern System.

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Figured we might as well get this one going. The Euro has this system effecting the area in less than 5 days. GFS day 5-6. We've all seen the model runs, some version of this event has been showing up for a week or so now, but as is typical with Southern systems the models are all over the place from run to run. Today they've generally came into agreement that there will be a system that will effect at least some of the region. Up in the air as to which parts. Could be winter as far south as the 1-20 corridor, could be Northern TN/Southern Ky/SWVA and everyone in between. 

There is even a minor system that ushers in cold just before this one that might provide some minor accumulations. This time frame should be the event to watch but that too is up in the air still due to massive model madness.

Best case for the region comes from quite a number of GFES ens members. Most of them show a wide variety of systems that hit in favorable ways for our region. Thus the beautiful means map that gives solid averages to about as wide a swath of our area as you'll ever see. That just shows how many of us are in the game at this point. 

Worst case is probably the 00z GFS op. It's a miller b type which means warming for most of the valley region. Maybe not all, it even has a front side thump. Some of us picked up a nice event out in front of a rainer last year. Next is the GGEM which was a little too far south but still gave the area a decent 1-3 inch average.

I've not seen a 6 hour breakdown on the Euro, but I know the following panel is a look I'd take all day long in winter.

 

ecmwf_T850_us_6.png

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18z GFS Para shows the love to the far southern Valley areas and a little south of there towards I-20.

gfsp_asnow_eus_25.png

 

18z GFS OP was an enhanced version of that. These runs came with the storm being a little less wound up out west and starting a little further south. That allowed them to drop further south before winding up and kept us all in the cold.

gfs_asnow_eus_34.png

 

Tonight's 00z GFS started further north, was a bit stronger and starting trying to get negative tilt in the plains, a big area of HP pressed in to it's NW and kept it from cutting. Instead it weakens as it heads SE then due East along the I-40 corridor. That lead to extremely heavy snow in southern and central Kentucky with decent snows along the border. This would also be an ice threat in the east as models usually struggle with too quickly warming temps during heavy precip rates.  This seems to be the northern extent of the track over the past number of days, I don't remember the last time a true cutter was modeled, I think maybe the Canadian 2-3 days ago was the last. Miller B/Apps runner seems to be the northern edge of operational models. The GEFS had a number of Gulf Coast lows and a few that tracked similarly to the 00z op in it's suite. 

 

00Z GFS with the I-40 track.

snku_acc.us_ov.png

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Thanks for starting this, John.  It's great to be staring opportunity in the face less than 7 days away, on January 2nd......in the Mid-South.

Here is the 6Z GEFS snowfall map.  Mean is beefy and lots of great hits, but also several whiffs too.  All in all, should be a fun week of tracking.

 

IMG_4434.PNG

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You can really see the difference early on with the second piece of energy.  0z vs 6z for the same time frame. Faster and open with the energy. Both are fairly robust, but small differences there and other places will greatly affect the outcome.

 

IMG_4435.PNG

IMG_4436.PNG

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I like the position of the 6Z with heavier snow axis south, we've all seen many times within the last 3 days of modeling a shift north and northwest with precip.  Also if I were to take the GFS features verbatim, I would actually bump a lot of the northern totals up a bit as again we often see undermodeled northern precip shields on these storms.  All and all I love the 6Z and would happily take more 6Z GFS runs. 

Not to mention northern areas of that run are not going to be 10:1 as Tropical Tidbits shows in totals.  

** Moved from main winter thread, didn't realize we had a storm thread**

 

6ZGFS.jpg

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The 6z runs for the GFS and GFS PARA are virtually identical at hour 102 at 500.  I willl just show North America, but widening the view really doesn't change things.

Is it right, no clue....but at least it's consistent with the representation of the energy we are all watching and also the other players involved.

 

IMG_4437.PNG

IMG_4438.PNG

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Though often unreliable at 84, the NAM should be able to provide some minor info as some of the players are coming into its range.   Will be interesting to see where it leads.  And for newcomers, at 84 it can be totally unreliable.  Just looking in this case for any nuggets that might hint that something correlates.  Use with caution.

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Still images yanked from Brad P's video in the SE forum.  (Not sure if the "futurecast is an in house model or the GFS) Good met and nice discussion. Recommend wandering over there and checking it out.

 

IMG_4439.PNG

IMG_4440.PNG

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As we know, 500mb will determine to a large extent the future of this event. The Para has been doing well at 500mb this year per verification scores. Better than the regular GFS and on par with the Euro. Also, inside of 5 days they start getting very high correlation scores at 500mb. So it's pretty nice to see essentially every model producing a miller A track or something close to it in it's latest run. 

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5 minutes ago, tnweathernut said:

H5 looks a little deeper at 102, will probably be a little north, but east coast still looks good.  Should be another nice run, let's see where it goes

it dropped to the gulf at 114 looks like last run little stronger really blossoms at 120

gfs_mslp_pcpn_frzn_us_20.png

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1 minute ago, tnweathernut said:

Opening back up, remaining positive tilt, still digging at 120.  Beautiful representation of a mid south snowstorm on the 12z. H5 is a beauty...

Do not see them much more textbook than that!

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Need the Euro to show this now and not shear the system out with lighter amounts.Good news i guess we are in the mid range and both show a system and snow.

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Just now, Mrwolf1972 said:

snow totals

sn10_acc_us_ov.png

How does that compare to the totals from 06Z? Looks a little more moist statewide and not so much towards the south but this is enough to shut down Memphis and Chatt for a day or two

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