Southern Plains winter wx thread (2009-2010)

[Peanut432]

The Cobb Output based on the 00z NAM shows the following accumulations for Oklahoma City and Norman...

OKLAHOMA CITY
Snow = 2.6"+
Sleet = 1.07"
Frz Rain = 1.58"

NORMAN
Snow = 1.4"+
Sleet = 1.13"
Frz Rain = 1.83"

We better hope and pray that the NAM is wrong! Over 1.5" of freezing rain would be absolutely devastating if it verified! I really, really hope that we switch over to snow/sleet more quickly than the NAM is showing and avoid this disaster!

I will post the 00z GFS Cobb output once it becomes available. As of right now I predict, based on what i'm seeing, that the GFS output will include more in the way of snow/sleet accumulations and less in the way of ice (which is VERY GOOD).

(BTW: This is where I am obtaining the above information -> http://www.meteor.iastate.edu/~ckarsten ... index.html )

When does the GFS come out exactly? Which is more accurate for this time frame

[srainhoutx]

Could someone give me an educated guess at this point for Memphis, TN? Thanks!

Going to be real close on p-type issues for Memphis. You are in an area outlined by the HPC so pay close attention to the NWS tomorrow.

[Extremeweatherguy]

The Cobb Output based on the 00z NAM shows the following accumulations for Oklahoma City and Norman...

OKLAHOMA CITY
Snow = 2.6"+
Sleet = 1.07"
Frz Rain = 1.58"

NORMAN
Snow = 1.4"+
Sleet = 1.13"
Frz Rain = 1.83"

We better hope and pray that the NAM is wrong! Over 1.5" of freezing rain would be absolutely devastating if it verified! I really, really hope that we switch over to snow/sleet more quickly than the NAM is showing and avoid this disaster!

I will post the 00z GFS Cobb output once it becomes available. As of right now I predict, based on what i'm seeing, that the GFS output will include more in the way of snow/sleet accumulations and less in the way of ice (which is VERY GOOD).

(BTW: This is where I am obtaining the above information -> http://www.meteor.iastate.edu/~ckarsten ... index.html )

When does the GFS come out exactly? Which is more accurate for this time frame

The GFS has already run, but the COBB precipitation amount data has not been generated yet. It will be probably arrive sometime soon though. As for accuracy, I am not really sure which of the two models does better in a storm situation like this one. I am sure they both have their strengths and weaknesses in a setup such as this. May be somebody else could answer that for you.

[Junia]

Could someone give me an educated guess at this point for Memphis, TN? Thanks!

Going to be real close on p-type issues for Memphis. You are in an area outlined by the HPC so pay close attention to the NWS tomorrow.

Thanks, srainhoutx, will do. Looks like a mess Thursday night into Friday so far.

[Extremeweatherguy]

The Cobb Output based on the 00z GFS shows the following accumulations for Oklahoma City and Norman...

OKLAHOMA CITY
Snow = 13.0"
Sleet = 0.13"
Frz Rain = 1.16"

NORMAN
Snow = 5.9"
Sleet = 0.94"
Frz Rain = 0.82"

The GFS, while showing less icing than the NAM overall, is still depicting a dangerously high level of freezing rain for central Oklahoma on Thursday. On top of the ice it also drops upwards of 6-12" of snow/sleet! Overall, this scenario might actually be just as bad if not worse than the NAM.

[Extremeweatherguy]

Here is my current personal forecast for the event. At the moment I am not going quite as extreme as the models, but I am still depicting a very severe storm for the area. A heavy glazing of ice followed by snow and gusty winds will likely lead to widespread downed trees, power outages, and impassable roads. It is not going to be pretty!

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

[Peanut432]

I have to believe that the 1.5 freezing rain in OKC = some week long power outages

[somethingfunny]

I have never seen anything appraching 1.5" of freezing rain in my life. Maybe .25"-.5" during my worst ice storms. That would be horrific if it verifies.

Sure hope the Oklahoma National Guard is being mobilized, it sounds like they're going to be busy this weekend.

[Extremeweatherguy]

What really makes the ice with this storm scary is the fact that there will be breezy winds throughout the event. Usually ice storms tend to be accompanied by fairly light winds, but not this one! The winds will help to add extra stress to the already ice loaded trees and power lines. This will mean a chance of horrific damage across the region if we see the freezing rain totals currently being predicted by the models.

[Peanut432]

The GFS cobb only show 2.6 inches of snow in Childress and .45 inch of sleet. Yet it has the total qpf at 1.66. Am i missing something? How much mostiure is in a .5 in of sleet?

The Nam on the other hand shows 1.30 of freezing rain

[Extremeweatherguy]

The GFS cobb only show 2.6 inches of snow in Childress and .45 inch of sleet. Yet it has the total qpf at 1.66. Am i missing something? How much mostiure is in a .5 in of sleet?

The Nam on the other hand shows 1.30 of freezing rain

The other QPF is shown falling as normal rain before the temperature cools enough to support wintry precipitation according to the GFS. The NAM on the other hand brings the cold air in slightly faster and thus drops the freezing rain depicted on its output.

[BlueIce]

What really makes the ice with this storm scary is the fact that there will be breezy winds throughout the event. Usually ice storms tend to be accompanied by fairly light winds, but not this one! The winds will help to add extra stress to the already ice loaded trees and power lines. This will mean a chance of horrific damage across the region if we see the freezing rain totals currently being predicted by the models.

Looks like emergency management is getting prepared for the event.

OEM is working with FEMA to preposition industrial size generators in McAlester and Oklahoma City . The generators will be used in the event of power outages requiring shelters and to provide power to water treatment facilities in the event of electric service disruptions. The FEMA generators will augment the industrial size generators OEM already has positioned around the state

[Extremeweatherguy]

06z NAM cobb winter precipitation accumulation output...

OKLAHOMA CITY
Snow accumulation = 2.4"+
Sleet accumulation = 0.79"
Freezing rain accumulation = 2.36"

NORMAN
Snow accumulation = 1.8"+
Sleet accumulation = 0.44"
Freezing rain accumulation = 2.30"

06z GFS cobb winter precipitation accumulation output...

OKLAHOMA CITY
Snow accumulation = 9.4"
Sleet accumulation = 0.0"
Freezing rain accumulation = 1.05"

NORMAN
Snow accumulation = 4.8"
Sleet accumulation = 0.75"
Freezing rain accumulation = 0.85"


Overall I would say that the GFS totals look a little more realistic to me right now. The NAM verifying is not impossible though, and if it does then everyone needs to prepare for extreme damage. 2+ inches of ice plus wind would equal a top level extreme ice storm. The GFS thankfully is not as extreme, showing the snow/sleet line arriving sooner and thus ending the ice. The GFS is by no means "good" though. It is still showing about an inch or so of ice across most of the area, which with the wind would be capable of generating extensive tree damage.

[Weatherdude20]

Wow, be careful Oklahoma, good luck national guard and Governer Henry.

[msstateguy83]

if that low dont start going a bit more north or turn north there is gonna be probs to the south.. watchin it closely on sat image i know there is still plenty of time for a northward movement but i have not seen it yet...

[Extremeweatherguy]

Luckily the 12z NAM has come down just a bit in freezing rain totals. Instead of the incredible 2+ inch amounts that the 6z showed, the latest 12z run is closer to 1.00-1.25 inches of freezing rain. That would still be a very severe storm, especially with the wind, but not quite as "epic" as 2+ inches would be. Hopefully this trend toward less freezing rain continues.

[brewskymc]

Luckily the 12z NAM has come down just a bit in freezing rain totals. Instead of the incredible 2+ inch amounts that the 6z showed, the latest 12z run is closer to 1.00-1.25 inches of freezing rain. That would still be a very severe storm, especially with the wind, but not quite as "epic" as 2+ inches would be. Hopefully this trend toward less freezing rain continues.

True... I hope that those higher ice totals don't come to pass.

[Tireman4]

Stay safe folks.

[msstateguy83]

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http://www.koco.com/video/22356041/index.html

[Extremeweatherguy]

Here is my latest personal prediction for the storm...





It looks like the best chance for significant snows will be in northern and northwest Oklahoma, and the best chance for significant ice will be across central Oklahoma extending from the SW to the NE part of the state. There is likely to be a narrow strip of very significant icing within the larger ice storm zone, with amounts exceeding 0.75" within that corridor. Ice amounts of that magnitude coupled with breezy winds will likely cause significant damage to trees and power lines.

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.