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

[Rocky Rascovich]

Karen, good point about the NAM/GFS discrepancy. I found an 18Z GFS forecast sounding and (for us) it seems to paint out the same basic idea as the 00Z NAM (sleet) so perhaps they've converged somewhat.


Tim[/QUOTE]


Tim, I so hope your right on this, I'm eagerly awaiting the 0Z runs and the forecast soundings for tomorrow night, I was going with a IP/ZR mix for here on north after 0Z tomorrow evening.. just maybe the latest NAM will work if the GFS gets on board. I don't think I could handle one of these catastrophic ice storms. It's heart wrenching seeing mutilated trees for a couple few years over one major ice event, but as I'm too painfully aware, this is a facet of winter on the southern plains that one must put up with..

 

[Brendon Lindsey]

This is the synoptic setup for 00Z Friday according to the NAM. It's essentially a LLJ feeding intense isentropic lift over the frontal surface. This is just an 850 mb chart and is not 3-D but gives the general idea:

Karen, good point about the NAM/GFS discrepancy. I found an 18Z GFS forecast sounding and (for us) it seems to paint out the same basic idea as the 00Z NAM (sleet) so perhaps they've converged somewhat.

One thing is for sure... if we end up with RA, FZRA, or SN, we'll have quite a spectacular case study, as there's no way I can reconcile those thermal fields as being anything but sleet.

Tim

Well if you are talking about 10-12 in of forecasted snow in N. Central is gonna be all SLEET then I will be witness to a true historic event... That would be cool.

 

[Chuck Robertson]

It just seems a little hard to believe the snow totals that are being forecast for the TX Panhandle for Thur. Yes, it is going to snow very heavily, but I don't think it will be for long enough of a duration to collect such massive amounts. I think the latest official NWS AMA forecast is for 8-12 inches, with locally higher amounts. However, given that the event should start out as several hours of freezing rain and or ice pellets, combined with the fact that precip should begin winding down in the TX panhandle area by shortly after dark Thursday, just doesn't give enough time to create too great of depths.

Yes, we will see very heavy snow tomorrow, but likely not lasting that long. I am leaning toward the 8 inch side of the forecast rather than the 12 or more side.
Chuck Robertson

 

[Mike Umscheid]

It just seems a little hard to believe the snow totals that are being forecast for the TX Panhandle for Thur. Yes, it is going to snow very heavily, but I don't think it will be for long enough of a duration to collect such massive amounts. I think the latest official NWS AMA forecast is for 8-12 inches, with locally higher amounts. However, given that the event should start out as several hours of freezing rain and or ice pellets, combined with the fact that precip should begin winding down in the TX panhandle area by shortly after dark Thursday, just doesn't give enough time to create too great of depths.

Yes, we will see very heavy snow tomorrow, but likely not lasting that long. I am leaning toward the 8 inch side of the forecast rather than the 12 or more side.
Chuck Robertson

I definitely agree with you in the eastern Panhandle... but the western/northwestern Panhandle, there should be very little sleet. What little sliver of warm layer aloft north and west of AMA should be eroded quickly with intense vertical motion... which, as a snow nut, is why I chose Dumas over farther east. I don't think areas like Canadian will see a foot of snow. Dumas, well, I'm still holding firm with 12-15" here. The moisture and kinematic fields support extreme precipitation rates with a number of hours of 1.5 to 2" per hour rates possible where it's all snow. I certainly hope that's here in Dumas!

 

[Jason Boggs]

Yeah, looking at the models I agree with you 100% Mike. At the station we were debating on when the precip would change over to snow and came to the same conclusion as you. I agree that the higher snow totals will be in the NW Panhandle due to the transition to snow much quicker than the rest of the fcst area.

The RUC's precip mode is snow right off the bat in the NW Panhandle at about 13Z with snow pellets south of I-40 at the same timeframe. At 15Z it shows a mixture of pellets and freezing rain in most of the Panhandle except for the NW portion. I agree that the Dumas-Dalhart area is a pick spot for maximum snowfall potential.

 

[Jason Boggs]

By the way, this graphic makes the most sense out of any of the fcst snow models. Right now, I'd go with this one.

SNOWFALL FCST

 

[Chris Wilburn]

It looks like the precip. mode will be all snow for the northern TX panhandle from before noon Thursday through after midnight. I can see a foot of snow or more for sure validated in this area.

 

[Mike Umscheid]

I discussed the precip type challenge a little bit with a 4-panel chart of the 00z NAM12 run valid tomorrow at 12z, 15z, 18z, 21z on the blog post linked below. Based on my experience, the Warm Layer Aloft maximum temperature "rule of thumb" works very well in the Top Down Approach for precip type:

http://www.underthemeso.com/blog/?p=1119

 

[Brendon Lindsey]

Well Mike, there is a new MD out backing your NW TX Panhandle theory. I noticed the dotted line predicting the path of precip in the image... Maybe we will need to start a now thread here in a few hours...

 

[Tim Vasquez]

Well if you are talking about 10-12 in of forecasted snow in N. Central is gonna be all SLEET then I will be witness to a true historic event... That would be cool.

No, I can't speak for north central Oklahoma... just the OKC area itself. Fifty miles north or south can make a world of difference.

Tim

 

[Jeff Piotrowski]

ICE STORM OKLA!!

One of single most important things is to look at today is the dew points and wet bulb 32 line.

The dew points now 12-19 along and North of the I-40 corridor.

The same time temps around 35 in southern OK to 25 in the North.

Moderate rain to heavy rain is rapidly developing in SW OK into central OK.

Rain rates now .25-.50 per hour from Lawton moving north into the very
low DP air expect the temps to drop into the upper 29 along the I-40 corridor with rapid glazing of power lines and trees.

This storm is going to have lot's of surprises!!

Mike out in Dumas Moderate snow is just WSW of Dumas!

UPDATE: HWY patrol reporting jack knife truck on I-40 mile marker 34.

Reports in SW OK trees & power lines now have rapid ice accumulating.


The OK mesonet sensors south of I-40 and western okla are now going off line. Power?

 

[Rocky Rascovich]

Here at the farm, 5mi. NW of Piedmont, OK. ..as of 8:22am 32F, glazing just starting with light ZR. Wind NNE gusting to around 25mph. Hope the column can cool quickly enough to transition to IP.. the sooner the better.

 

[Rocky Rascovich]

If the latest RUC verifies, at least here in the Piedmont area, we may transition to IP as soon as 17Z. ZR really picking up though, tree damage may not be as severe but power, that's another story.

 

[Andrew Francis]

Precip shields is very large. And consistently moderate-heavy throughout. I can see north TX panhandle getting the 12" + amounts.

Here in Central OK it is currently light FRZA @28 degrees in Edmond. Local stations reporting trees breaking and heavy glazing in SW OK. Pretty good shield of precip out ahead of the low here in OK. It looks like the Low is moving more north than north east. Hoping for a jog eastward or us in OK could find ourselves in a little dry slot this evening and waiting for wrap around fun.



EDIT:
I-40 heading East into OK from Weathorford is closed. Semi truck has overturned and is laying sideways across all lanes. Traffic backed up for a very long time.

 

[Karen Politte]

Well the 12Z ETA actually came back slightly more vigorous on the frozen precip chances for AR than I had been expecting......the 36-42hr panels in particular interest me, but I'm still not loving how we are STILL sitting on the edge of 32oF here in Conway the whole time. I'm not sure if that worries me or not, though - temperature trends across northern AR and the Ozarks have been responding very well to the feed of sub-30oF coming down from MO this morning, with Flippin and Fayetteville probably in the upper 20s right now. Just wish the terrain would allow that cold air down here!

'Mon the snow, or sleet, or frzra......anything!

KP