December 4-6 winter storm potential TX/OK/KS/AR/MO/IL

[John Massura]

Potential seems to be increasing for a decent snow event, mainly in a narrow band from OK, northeastward into IL. Have been watching this pretty much all day. I suspect the links below may change.

http://wxcaster4.com/nam/CONUS1_ETA212_SFC_ACCUM-SNOWFALL_84HR.gif (84-hour snow forecast from the 03/0000z NAM run)

http://grib2.com/gfs/CONUS_GFS0P5_SFC_ACCUM-SNOW_84HR.gif (84-hour snow forecast from the 03/0000z GFS run)

The NAM began going nuts with the heavy snow on the 02/0600z run, and it has continued all day through the current 03/0000z run. The band has remained in a similar orientation, but very narrow. The GFS has been indicating a slightly later start time, and a broader area of lighter snowfall for this entire period. Will be interesting to watch. The GFS solution seems to be a bit colder and farther south, with mainly a snow event. The NAM is a bit slower with the cold air at the surface, with a chance of some sleet/freezing rain with the earlier onset. Doesn't seem to be a widespread or major issue though at this time. Soundings for the OKC area seem to indicate virtually all snow with both model solutions.

Most of the forcing seems to be at upper-levels, with the NAM kicking out a slightly stronger vort max Sunday night, with the GFS shearing it out a bit quicker. Both models indicate a fairly impressive dual-jet streak structure over the Southern Plains. Due to this relative lack of low-level forcing and WAA, I would think to lean in the direction of the GFS amounts, though I believe these dynamic systems give the SPlains it's big snowfalls. However, the amounts could very well depend on the storm track, with the NAM a bit farther north, allowing some slightly better moisture north at 850mb or so.

From last year, the NAM over-estimated snowfall a lot, and combined with time of year, the snow amounts it is spitting out do seem to be a bit high. Will be fun to watch though as usual. I'm not a huge winter weather forecaster, so any critiques of my thoughts would be welcomed!

(edit) Trial and error skills enabled me to attach the actual images, which shouldn't change! Yay.
(edit 2) They changed. Pooper...I fail at internets.

 

[Chip Redmond]

Rex block breaking down will allow high pressure in the west to funnel in much colder air further south and east over the next week and a half. With the trough shifting eastward, the system has good potential (as long as the current system doesn't cut off all the moisture and returns are strong with early week storm). For regions such as the midwest and snowbelt areas, it has been a surprisingly quiet start to the snow season. The next system that will affect into the Great Lakes will also allow the development of a potential nor'easter mid-week next week. This is the first true push of cold arctic air for the nation and the first real presence of winter that many have been lucky to avoid thus far. Most likely the majority of the US will see snowflakes that have been spared thus far. Tis the season!

Chip

 

[Andrew Francis]

Like most of the southern plains storms, it is all going to come down to exactly where the system tracks northeast. Right now it looks like Norman to Tulsa could be the winners with the heaviest band (in OK). Won't know until probably Sunday night as the low is ejected.


Either way, it is pretty textbook!

 

[RMacDonald]

This would will be pretty nice to watch, hoping get some more validation on my SmartCast with this one. Right now my SmartCast is showing 5th between 12Z-17Z where it changes over to all snow, right now hitting on only light accum. < 1" waiting to see how it adjusts over the coming hours.

 

[Andrew Francis]

Well this storm fell flat on its face.

Looks like little to no snow now for C OK. And maybe a wet trace in parts of Eastern OK - that will probably melt quickly due to temperatures. Models try to get the act together once the storm moves into MO, but even then it looks to be a thin swath of mediocre totals.



At this point just hoping to see a few flakes here in C OK for the first time this winter season!