Jump to content
  • Member Statistics

    17,589
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

Christmas Grinch Storm Part 2


Chicago Storm

Recommended Posts

  • Replies 575
  • Created
  • Last Reply

GFS soundings verbatim are going to be warm and look very marginal for snow, which can be seen on the COBB outputs. However, the GFS is showing very impressive frontogenesis and omega in the deformation axis, which results in the high qpf values. Also to start, there is some negative EPV present. In this sort of setup, the marginal BL conditions are typically overcome by dynamic cooling to favor snow as the p-type. Models do not handle it well, so mid 30s 2m temp and dewpoints the model is showing would likely be forced down to low 30s by the heavy precipitation in reality. A good recent example of this was the snowstorm on 2/7/13 in northeast IL and southern WI. If I can figure out how to upload some AWIPS screen caps I took from the 12z OP GFS, I'll put them up as an example.

Glad someone brought this up as I was wondering if this would be one of those setups where evap cooling plays a role.

Of course, this only adds more uncertainty to the forecast.

Link to comment
Share on other sites

RCNYILWX, on 22 Dec 2014 - 10:38 AM, said:snapback.png

 

 

GFS soundings verbatim are going to be warm and look very marginal for snow, which can be seen on the COBB outputs. However, the GFS is showing very impressive frontogenesis and omega in the deformation axis, which results in the high qpf values. Also to start, there is some negative EPV present. In this sort of setup, the marginal BL conditions are typically overcome by dynamic cooling to favor snow as the p-type. Models do not handle it well, so mid 30s 2m temp and dewpoints the model is showing would likely be forced down to low 30s by the heavy precipitation in reality. A good recent example of this was the snowstorm on 2/7/13 in northeast IL and southern WI. If I can figure out how to upload some AWIPS screen caps I took from the 12z OP GFS, I'll put them up as an example.

 

 

 

 

From part I on this storm topic: 

 

Yeah I remember that event really well. What was supposed to be a longer period of mixed precipitation in the morning into the afternoon, turned out to be a 95% snow event, where I picked up 10". Went from a bit of drizzle to straight moderate snow within a half hour.

 

Just plucked these soundings off of Twisterdata. Location at the state line here.

Not seeing that pronounced mid level warm layer now.

 

GFS_3_2014122212_F54_42.5000N_88.0000W.p

 

GFS_3_2014122212_F60_42.5000N_88.0000W.p

Link to comment
Share on other sites

GFS/PGFS/GEM/WRF bros agree on a nice swath of snow from central IL up through Chicago and up into western/northern MI with the 12z.  12km NAM in the farthest southeast camp with a nice hit from LAF up into the southeast half of MI.  4km NAM and RGEM smoke the northwest half of IL and southern WI.  Still some outliers on both sides, but the GFS/PGFS consensus of a central IL to Chicago hit is looking the best at this point IMO.

Link to comment
Share on other sites

GFS/RGEM/NAM surface low tracks.  For some reason the GGEM didn't plot but its track is similar to the GFS.  Notice the left hook at the end by the RGEM.  Quite a gap between the RGEM/some other hi-res models and the other stuff.  The RGEM never really gets the surface low into the Gulf of Mexico.  This is a tough one as far as which camp to lean toward.  As I said before, I wouldn't rule out anything yet so the best course for now may be some sort of compromise.

 

 

post-14-0-49666300-1419270644_thumb.gif

Link to comment
Share on other sites

it's baby stepping west in line with the other non-euro guidance

 

I don't think I have a shot at this one, I really just want to see NW lower get in on the action......

 

For my own sake, another 100 miles west is fine... The GFS and 4K NAM screw the entire state of Michigan.

 

Oh well, this lack of winter is saving me lots of money.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...