FORECASTS: 1/28/10 - Southern/Central Plains Winter Storm

[Jeff Piotrowski]

Here we go again?

The models are trending slower and colder with this next system for Thursday. The GFS has snow across Oklahoma ranging from 6"-18" by 12Z Friday. http://wxcaster4.com/gfs/CONUS2_GFS0P5_SFC_ACCUM-SNOW_120HR.gif most likey on the high side but good snow storm.

The GEM & ECWMWF all point to least a good chance of heavy snow in Oklahoma on Thursday.

 

[Jason Boggs]

Yep! The GFS has about 13 inches for us here in Amarillo. I hope it pans out!

 

[Andrew Francis]

Looking like a potentially significant storm @ this point. Will be interesting to see if the system actually takes the southern track.

Going to be hard to convince people that we may be looking @ another winter storm after we just melted off the Christmas Eve snowpiles w/ the last week or so 50-60 degree temps.

 

[Chris Wilburn]

I agree they may be trending on the high side Jeff like they always seem to do. With that said, I still expect somewhere in OK to receive some fairly significant amounts of snow. Also, looks like some icing is possible as well. Snowfall amount similar to Christmas Eve are showing up on the GFS. The NAM for tomorrow morning will go out until 7pm Thursday so we will see what it has to say.

 

[Andrew Ryan]

What??!?!?!

Oh, well, this is OK, so all I need is 1" to get a week off from school. So if I were to take the GFS to verbatim, that's about 6 months off.

But seriously, with the recent warm weather, the snow/sleet may have a hard time sticking to anything other than grassy surfaces.

 

[mark plate]

While some snow is possible across parts of northeast Oklahoma...to me this one has ice storm written all over it for the Tulsa metro the way it looks now. The cold air looks to be quite shallow initially, and much of the QPF looks to fall before the thermal profiles look cold enough for snow...maybe a few inches of snow at the end, but I'm more worried about ice than snow right now.

 

[Chris C Sanner]

While some snow is possible across parts of northeast Oklahoma...to me this one has ice storm written all over it for the Tulsa metro the way it looks now. The cold air looks to be quite shallow initially, and much of the QPF looks to fall before the thermal profiles look cold enough for snow...maybe a few inches of snow at the end, but I'm more worried about ice than snow right now.

I was coming here to say the same thing...this has definite ice storm written all over it if the GFS is to be believed.

If the precip is as forecast and the winds are 25-40mph as projected, expect the damage to be significant. Models also don't handle shallow cold-air intrusions like this very well from memory, so the freezing line could be a lot farther south than progged as well.

Either way, this looks to be a potentially significant winter storm.

 

[Greg McLaughlin]

The one thing that favors sleet/snow over a prolonged ice event is the cold air advection. I have been watching the models and they don't show strong 850mb WAA (overrunning effect) across northeast OK during the event. Instead it appears most of our precip will fall post-frontal and thermo profiles will continue to cool through the event. I wouldn't be surprised to see a short period of freezing rain with maybe a quarter of an inch ice accumulations. I wouldn't be surprised to see a quicker transition to sleet, and then a slower transition to snow.

Its all up in the air at this point, but from what I can make of things I still believe we will have a fairly quick transition to sleet. I must add, it has been my experience that the models tend to underestimate the strength of shallow arctic airmasses, This one is going to come right down to the last minute.

 

[Brendon Lindsey]

Wow look at the snow depth totals 84 hours out on the 12z NAM!!!

That would be the Christmas eve storm over again, but bigger and deadlier.
Its showing 12"+ throughout 50% of OK. The GFS shows another scenario but definately not as extreme, but still snowfall.

 

[rdale]

12Z NAM has no snow for Oklahoma City -- all rain to freezing rain & sleet. 12Z GFS has 6" of snow.

http://66.70.209.226/weather/snow/oun.txt

 

[Brendon Lindsey]

Well twisterdata 12z 84 hours out NAM has 14-16 in for OKC atleast the "snow depth" option

 

[Andrew Ryan]

Well twisterdata 12z 84 hours out NAM has 14-16 in for OKC atleast the "snow depth" option

But that's not consistent with the upper levels on the NAM. For almost the entire duration of the storm, the 850-700mb levels are above freezing. That means that the precip mode with likely be sleet and not snow. So, I don't understand why it's outputting snowfall totals of 1'+.

 

[Brendon Lindsey]

Well I assumed that the "snow depth" was experimental. It did verify on the Chris. Eve. storm. Ill take a look at the upper air models... That would be crazy if that did verify though. I believe it would be historic if that came true, seeing as we already broke records with the previous storm.

 

[rdale]

It's probably just taking the QPF and multiplying by some number. That's not a valid method...

 

[Greg Blumberg]

Yeah..I wouldn't trust the snow depth product at all. Too many factors and not enough knowledge regarding those factors to consider it to be a valid tool. But from the 12z GFS's current look I'd say sleet is what we'll get. There's way too much of a layer above freezing between 700-850mb on the forecast soundings at 0z. The 12z GFS also barely passes the expected thickness values test for forecasting snow. Despite all this...six hours later the sounding looks much better for snow development in the central OK area.

I'm always very skeptical for forecasting these events in central OK. The two things that have always screwed up the forecasts in the past were not handled well by the models. Those two things are the position of the low/snow band and dry slot killing the moisture. In my experience, the dry slot is always what kills it.

Here's to hoping for a good snow!