Southern Plains winter wx thread (2009-2010)

[Extremeweatherguy]

If today's 18z GFS were to play out, then we would be dealing with a significant winter storm across the northern 1/2 of the southern plains early/mid next week. It looks like the Oklahoma and north Texas region could be a battle ground zone, with several precipitation types occurring over the area at once. I've definitely got my fingers crossed...especially with the discussion of the airmass possibly being even colder than the current model output is suggesting, but for now I am not taking any one model solution too seriously.

Just for fun though, let's take a more detailed look at the 18z GFS...


MONDAY
Cold air spilling south across the plains. Afternoon temperatures falling below freezing in northern Oklahoma and into the 30s in southern parts of the state. The freeze line settles near the Red River overnight with gradually increasing clouds.

TUESDAY MORNING
At daybreak the surface freeze line is parked along the Red River, with the 850mb 0C line slightly further north. Temperature and precipitation profiles indicate light snow showers occurring in north Oklahoma with light sleet showers in central Oklahoma. Precipitation has yet to really build in along the TX/OK border, but anything that did fall would be in the form of light freezing rain or a light freezing rain/sleet combo.

TUESDAY AFTERNOON
The surface freeze line lifts north into central Oklahoma by the afternoon, with the 850mb 0C line located in the same region. The 540 thickness line is over northern Oklahoma. At the same time, precipitation is becoming heavier, with moderate snows falling across northern Oklahoma and moderate sleet showers found in and around Oklahoma City, possibly mixing with some freezing rain. Further south toward the OK/TX border, the precipitation amounts are lighter and anything that fell would be in the form of light rain or a light rain/sleet combo.

TUESDAY NIGHT
This is when things really begin to get interesting. The model shows a push of reinforcing cold air arriving around this time, which would support a cooling of the surface and the upper levels under an increasing precipitation shield. By midnight the surface freeze line is in south-central Oklahoma and by 6am Wednesday it is into parts of north Texas. The 850mb 0C line also pushes farther south, clearing most of Oklahoma and encompassing a large area of north Texas by 6am Wednesday. The 540 thickness line follows suit, entering north Texas at the same time. With these factors in mind, we would expect to see a transition to snow for nearly all of Oklahoma and parts of north Texas by sunrise on Wednesday, with a mix of rain turning to freezing rain/sleet/snow reaching the Dallas metro at about the same time.

WEDNESDAY
By Wednesday afternoon the system begins to clear the area, with lingering precipitation confined mainly to SE Oklahoma and NE Texas. The airmass is still bitter cold though, with the afternoon surface freeze line draped across the Red River. Temperatures fall rapidly during the evening as yet another reinforcing cold airmass on top of a layer of accumulated frozen precipitation allows temperatures to fall well into the teens all the way to the Red River and into the single digits/lower teens for most of central and northern Oklahoma. Overnight lows would likely reach sub-10F numbers in the northern half of Oklahoma, and 10-20F for the southern half of Oklahoma into the northern most counties of north Texas.



All in all, this would be a pretty decent event for the area. Parts of Oklahoma could be under the gun for wintry precipitation, some of it moderate to heavy, for 24+ hours! Of course, this is all assuming the 18z solution were to play out exactly. Considering that the models have been flip flopping all over the place though, I wouldn't get too invested in this solution being right just yet. If by the weekend the models are showing something similar however, then it might be time to take note...especially if the models wind up trending colder with the overall arctic airmass (which seems very possible).

[mysterymachinebl]

If today's 18z GFS were to play out, then we would be dealing with a significant winter storm across the northern 1/2 of the southern plains early/mid next week. It looks like the Oklahoma and north Texas region could be a battle ground zone, with several precipitation types occurring over the area at once. I've definitely got my fingers crossed...especially with the discussion of the airmass possibly being even colder than the current model output is suggesting, but for now I am not taking any one model solution too seriously.

Just for fun though, let's take a more detailed look at the 18z GFS...


MONDAY
Cold air spilling south across the plains. Afternoon temperatures falling below freezing in northern Oklahoma and into the 30s in southern parts of the state. The freeze line settles near the Red River overnight with gradually increasing clouds.

TUESDAY MORNING
At daybreak the surface freeze line is parked along the Red River, with the 850mb 0C line slightly further north. Temperature and precipitation profiles indicate light snow showers occurring in north Oklahoma with light sleet showers in central Oklahoma. Precipitation has yet to really build in along the TX/OK border, but anything that did fall would be in the form of light freezing rain or a light freezing rain/sleet combo.

TUESDAY AFTERNOON
The surface freeze line lifts north into central Oklahoma by the afternoon, with the 850mb 0C line located in the same region. The 540 thickness line is over northern Oklahoma. At the same time, precipitation is becoming heavier, with moderate snows falling across northern Oklahoma and moderate sleet showers found in and around Oklahoma City, possibly mixing with some freezing rain. Further south toward the OK/TX border, the precipitation amounts are lighter and anything that fell would be in the form of light rain or a light rain/sleet combo.

TUESDAY NIGHT
This is when things really begin to get interesting. The model shows a push of reinforcing cold air arriving around this time, which would support a cooling of the surface and the upper levels under an increasing precipitation shield. By midnight the surface freeze line is in south-central Oklahoma and by 6am Wednesday it is into parts of north Texas. The 850mb 0C line also pushes farther south, clearing most of Oklahoma and encompassing a large area of north Texas by 6am Wednesday. The 540 thickness line follows suit, entering north Texas at the same time. With these factors in mind, we would expect to see a transition to snow for nearly all of Oklahoma and parts of north Texas by sunrise on Wednesday, with a mix of rain turning to freezing rain/sleet/snow reaching the Dallas metro at about the same time.

WEDNESDAY
By Wednesday afternoon the system begins to clear the area, with lingering precipitation confined mainly to SE Oklahoma and NE Texas. The airmass is still bitter cold though, with the afternoon surface freeze line draped across the Red River. Temperatures fall rapidly during the evening as yet another reinforcing cold airmass on top of a layer of accumulated frozen precipitation allows temperatures to fall well into the teens all the way to the Red River and into the single digits/lower teens for most of central and northern Oklahoma. Overnight lows would likely reach sub-10F numbers in the northern half of Oklahoma, and 10-20F for the southern half of Oklahoma into the northern most counties of north Texas.



All in all, this would be a pretty decent event for the area. Parts of Oklahoma could be under the gun for wintry precipitation, some of it moderate to heavy, for 24+ hours! Of course, this is all assuming the 18z solution were to play out exactly. Considering that the models have been flip flopping all over the place though, I wouldn't get too invested in this solution being right just yet. If by the weekend the models are showing something similar however, then it might be time to take note...especially if the models wind up trending colder with the overall arctic airmass (which seems very possible).

Interesting! Definitely something to keep an eye on!

[msstateguy83]

most definitely i think the models could be as alot of times happens under est the
moisture with this type of pattern setup i look for SEVERAL ROUNDS of ICE AND OR
SNOW STORMS IN THE COMING 7-14 DAYS across a large portion of the central/
southern plains region.. people should prepare for major disruptions in travel and
or power across this region heading into next week, iam not just saying this
when you have the door basically cracked open for artic air to just blast down
our way ANYTIME that happens you have the chance there or some type of
ICE/SNOW storm event.. gfs is hinting at something now the coming days will
for sure spread more light on this setup.

[msstateguy83]

THE NBC AFFILATE OUT OF OKLAHOMA CITY KFOR .TV SEEMS TO BE PICKING UP ON THIS ALSO

[Ntxw]

More snow would be wonderful, the ice ehh...could do without

[iorange55]

More snow would be wonderful, the ice ehh...could do without

Ice is very dangerous and nasty, but I have to admit the most fun I've had in a winter storm was a huge sleet storm that went through Dallas back in 2002-2003 which was an El-Nino winter btw. But it was below freezing for 3 days straight, and the sleet came down so hard. We went out sledding on golf courses, and helping people out of ditches, doing donuts. It was the most memorable winter storm for me. Of course I'd take 10 inches of snow over that any day, but sadly ice is more likely than 10 inches of snow in Dallas.

[Ntxw]

But so far this year, not many places around the country have seen freezing rain\sleet on a big scale, it's either been rain or snow. I wonder if this is a good sign for snow this winter.

[cheezyWXguy]

More snow would be wonderful, the ice ehh...could do without

Ice is very dangerous and nasty, but I have to admit the most fun I've had in a winter storm was a huge sleet storm that went through Dallas back in 2002-2003 which was an El-Nino winter btw. But it was below freezing for 3 days straight, and the sleet came down so hard. We went out sledding on golf courses, and helping people out of ditches, doing donuts. It was the most memorable winter storm for me. Of course I'd take 10 inches of snow over that any day, but sadly ice is more likely than 10 inches of snow in Dallas.

Oh my God best winter storm ever. 2 days off of school. So much precip that I couldnt tell the difference between the street and the sidewalk. Now If only the first inch could have fell in ice/sleet and the other 2-3 inches fell in snow, instead of all sleet.

[HarlequinBoy]

Hey EWG, what about over here in the Mid South? Do we have a shot at anything? We're getting gipped just like OKC is right now.

[Ntxw]

There is very cold air up in Canada and it's progressively coming down. There's a strong high pressure that the models have yet to grasp on very well. Lets see what tonight's 0z gfs has for next week and we can start discussing what we think could happen

[Extremeweatherguy]

Hey EWG, what about over here in the Mid South? Do we have a shot at anything? We're getting gipped just like OKC is right now.

Yeah, I suspect that if things do play out like the 18z GFS was suggesting, and especially if the incoming airmass is even colder than the model is projecting, then it seems like a pretty good bet that you guys in Memphis would get in on the action too. As of right now I think next week definitely has the potential to be interesting for both of us.

[Extremeweatherguy]

The 00z GFS is continuing the trend of a southern plains winter storm early/mid next week. It is a hair warmer at all levels than the 18z during the Tuesday time period, but I expect this to continue to change from run to run, with us not knowing exactly who will be getting what p-type on which day until we are only a day or two out. Still looks like it could be a mess though, with the potential for all p-types to be simultaneously occurring within a small regional area (snow, sleet, frz rain, and rain).

One thing that is worth noting is that the "new" GFS, the one that will be replacing the current GFS in 13 days, is coming in with a slightly colder solution than the current operational GFS. You can check out the differences below...

TUES EARLY MORNING (precip. and 850mb temps)
current GFS - http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_126l.gif
new GFS - http://www.nco.ncep.noaa.gov/pmb/nwpara ... p_126l.gif

TUES MORNING (precip. and 850mb temps)
current GFS - http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
new GFS - http://www.nco.ncep.noaa.gov/pmb/nwpara ... p_132l.gif

TUES AFTERNOON (precip. and 850mb temps)
current GFS - http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
new GFS - http://www.nco.ncep.noaa.gov/pmb/nwpara ... p_138l.gif

TUES EVENING (precip. and 850mb temps)
current GFS - http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
new GFS - http://www.nco.ncep.noaa.gov/pmb/nwpara ... p_144l.gif

WED EARLY MORNING (precip. and 850mb temps)
current GFS - http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif
new GFS - http://www.nco.ncep.noaa.gov/pmb/nwpara ... p_150l.gif

WED MORNING (precip. and 850mb temps)
current GFS - http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_156l.gif
new GFS - http://www.nco.ncep.noaa.gov/pmb/nwpara ... p_156l.gif

[mysterymachinebl]

Well, one of the meteorologists here have picked up on something. The guy on CBS 11 just forecasted a high of 39 for next Wednesday.

[Ntxw]

He's the one that generally isn't afraid to say the 'S' word. I remember a few nights ago he said that Dfw could get more snow this morning than we are led to believe but the bigger accumulations would stay west. Lord and behold, it happened all the way into Dallas.

[cheezyWXguy]

EWG, you beat me to it lol
I also noticed that while the GFS still isn't perfect, it looks much more realistic than previous runs. The 1060mb high is slower to weaken and pushes a bit further south, bringing colder air, and a 12-18 hour snow episode to NTX, with higher amounts in OKC. Based on the strength of the high, temperatures will likely be colder next week than the model shows, and based on the strength of the low moving along the subtropical jet at the same time, higher amounts of precip also seem likely for texas and oklahoma next week.
I may be wrong about this next part, but it looks like the 850mb 0C line lags behind the surface 0C line, meaning that the onset of winter precip in NTX will be sleet (possibly changing from rain in the beginning) and finishing with a changeover to snow, assuming this run verifies.
Someone please correct me if Im wrong on any of this.

[Ntxw]

EWG, you beat me to it lol
I also noticed that while the GFS still isn't perfect, it looks much more realistic than previous runs. The 1060mb high is slower to weaken and pushes a bit further south, bringing colder air, and a 12-18 hour snow episode to NTX, with higher amounts in OKC. Based on the strength of the high, temperatures will likely be colder next week than the model shows, and based on the strength of the low moving along the subtropical jet at the same time, higher amounts of precip also seem likely for texas and oklahoma next week.
I may be wrong about this next part, but it looks like the 850mb 0C line lags behind the surface 0C line, meaning that the onset of winter precip in NTX will be sleet (possibly changing from rain in the beginning) and finishing with a changeover to snow, assuming this run verifies.
Someone please correct me if Im wrong on any of this.

I kind of see what you're talking about, but it is still far out to determine that right now I think

[cheezyWXguy]

EWG, you beat me to it lol
I also noticed that while the GFS still isn't perfect, it looks much more realistic than previous runs. The 1060mb high is slower to weaken and pushes a bit further south, bringing colder air, and a 12-18 hour snow episode to NTX, with higher amounts in OKC. Based on the strength of the high, temperatures will likely be colder next week than the model shows, and based on the strength of the low moving along the subtropical jet at the same time, higher amounts of precip also seem likely for texas and oklahoma next week.
I may be wrong about this next part, but it looks like the 850mb 0C line lags behind the surface 0C line, meaning that the onset of winter precip in NTX will be sleet (possibly changing from rain in the beginning) and finishing with a changeover to snow, assuming this run verifies.
Someone please correct me if Im wrong on any of this.

I kind of see what you're talking about, but it is still far out to determine that right now I think

Yes, I agree, Im just basing purly off what I see from the 0z GFS, from a hypothetical standpoint. If the surface is below freezing and the 850mb line is slightly above, that would suggest sleet or freezing rain, right?

And for the record, Im not putting a whole lot of trust into this run, but I think I like the trend Im beginning to see.

[Ntxw]

Only two days into December and i'm liking every bit of it so far

[AggieSpirit]

More snow would be wonderful, the ice ehh...could do without

Ice is very dangerous and nasty, but I have to admit the most fun I've had in a winter storm was a huge sleet storm that went through Dallas back in 2002-2003 which was an El-Nino winter btw. But it was below freezing for 3 days straight, and the sleet came down so hard. We went out sledding on golf courses, and helping people out of ditches, doing donuts. It was the most memorable winter storm for me. Of course I'd take 10 inches of snow over that any day, but sadly ice is more likely than 10 inches of snow in Dallas.

Oh my God best winter storm ever. 2 days off of school. So much precip that I couldnt tell the difference between the street and the sidewalk. Now If only the first inch could have fell in ice/sleet and the other 2-3 inches fell in snow, instead of all sleet.

The 3rd night, when it dropped to the upper teens -- I decided to put on my ice skates and skated up and down the street in my neighborhood. The ice was soft compared to a rink -- but heck - I was Ice Skating on a street in Arlington Texas. What more could I ask for? The puck slid nicely too.

[Extremeweatherguy]

Even the usually conservative GFS MOS is starting to bite on next weeks possible event (especially for Oklahoma). Here is what the 00z MOS guidance is showing...

For OKC:

SUN
High - 43
Low - 29
Variable clouds with a 13% chance of precipitation (snow)

MON
High - 43
Low - 26
Variable clouds with a 19% chance of precipitation (rain/snow)

TUES
High - 38
Low - 28
Overcast with a 49% chance of precipitation (snow/sleet)

WED
High - 36
Low - 25
Overcast with a 44% chance of precipitation (snow)

For DFW:

SUN
High - 49
Low - 35
Partly cloudy with an 18% chance of precipitation (rain/snow/sleet)

MON
High - 54
Low - 38
Overcast with a 16% chance of precipitation (rain)

TUES
High - 54
Low - 38
Overcast with a 32% chance of precipitation (rain)

WED
High - 49
Low - 33
Overcast early then clearing with a 38% chance of precipitation (rain/sleet)

Unfortunately for you guys down in Dallas it still seems that the MOS guidance is way too conservative. It is likely going to be much colder for you guys than what it is showing. The trend is toward colder (and wetter) though, so things are definitely going in the right direction.