Texas Winter 2020-2021

[Iceresistance]

12z Euro Ensemble Mean and Control runs are showing snowfall amounts over 1 inch, with the potential for a major winter storm across much of the northern half of the state on Monday.

What are the 12z CMC Ensembles looking like in terms of Mean & Ensemble Snowfall?

[Texas Snowman]

I read somewhere, I do not know the quality of the source, that Covid has wreaked havoc on the amount of input data it receives. Though that seems like it should affect most all models equally. There is something about the Euro that is making it not near as resilient to lack of data inputs vs other models.

Yes, there's less data due to less flights is what I remember.

I know there are certainly less domestic flights, but I’d also guess there are far fewer intercontinental flights over the oceans? I’d think that decrease of data over the oceans could play a role.

[Portastorm]

I read somewhere, I do not know the quality of the source, that Covid has wreaked havoc on the amount of input data it receives. Though that seems like it should affect most all models equally. There is something about the Euro that is making it not near as resilient to lack of data inputs vs other models.

Yes, there's less data due to less flights is what I remember.

I know there are certainly less domestic flights, but I’d also guess there are far fewer intercontinental flights over the oceans? I’d think that decrease of data over the oceans could play a role.

NWS Austin/San Antonio talked about this during our basic and advanced SKYWARN training session last Saturday. A lack of data was indeed an issue last year when air travel was down significantly. However, the amount of flights has picked up some since last fall and NWS believes that it's not so much an issue anymore with the models.

[psyclone]

Confession: This Floridian (native to northeast OH) stalks the TX Winter thread on a regular basis. Love the enthusiasm. You guys are really in the hunt for some winter wx. We (peninsular FL) look to be the only safe spot...which is fine with me. All the best out that way.

[TeamPlayersBlue]

I wouldn't focus on the Euro surface temps, but watch the upper level pattern for precip.

To the mets on the board, as a SE TX guy, and a snow/ice snob, i'd like for us not to waste an opportunity for as much winter weather as possible. What are the chances we have precip from orographical lift from the HP slamming down into our area? Currently models dont see this for sunday, but I feel like it's a real possibility, before precip from a low arrives on Monday.

[Iceresistance]

I wouldn't focus on the Euro surface temps, but watch the upper level pattern for precip.

To the mets on the board, as a SE TX guy, and a snow/ice snob, i'd like for us not to waste an opportunity for as much winter weather as possible. What are the chances we have precip from orographical lift from the HP slamming down into our area? Currently models dont see this for sunday, but I feel like it's a real possibility, before precip from a low arrives on Monday.

Does that mean more or less snow?

[Iceresistance]

North Wind is picking up outside, 10-15 mph.

Snow is trying to fall & is being picked up on NWS-Norman radar

Currently 19°F outside with a Wind Chill of 7°F

EDIT: NWS-Norman has JUST issued a Winter Weather Advisory for Tomorrow for up to 2/10 inch of Ice.

[cheezyWXguy]

18z hrrr looks like the beginning of a more substantial icing event at hour 33.

[TeamPlayersBlue]

I wouldn't focus on the Euro surface temps, but watch the upper level pattern for precip.

To the mets on the board, as a SE TX guy, and a snow/ice snob, i'd like for us not to waste an opportunity for as much winter weather as possible. What are the chances we have precip from orographical lift from the HP slamming down into our area? Currently models dont see this for sunday, but I feel like it's a real possibility, before precip from a low arrives on Monday.

Does that mean more or less snow?

Means more moisture. Dense HP pushing/displacing air higher, creating lift.

What events can we look at to compare? Only one that comes to my mind is Jan 2018.

[HockeyTx82]

200 pages and the show has not even started

[Ntxw]

I wouldn't focus on the Euro surface temps, but watch the upper level pattern for precip.

To the mets on the board, as a SE TX guy, and a snow/ice snob, i'd like for us not to waste an opportunity for as much winter weather as possible. What are the chances we have precip from orographical lift from the HP slamming down into our area? Currently models dont see this for sunday, but I feel like it's a real possibility, before precip from a low arrives on Monday.

Does that mean more or less snow?

Means more moisture. Dense HP pushing/displacing air higher, creating lift.

What events can we look at to compare? Only one that comes to my mind is Jan 2018.

Maybe late Jan 1985 or early Feb 1973 had some severe -AO blocking with snow along the gulf. ENSO is a better match for 1985.

This is the daily AO leading to the severe blocking of Jan 1985 and eventual cold grip across the US. -6 which is pretty close to what the forecast is, we're approaching -5

Code: Select all

1985  1 13 -2.428
1985  1 14 -3.114
1985  1 15 -2.971
1985  1 16 -3.935
1985  1 17 -4.895
1985  1 18 -5.693
1985  1 19 -6.226
1985  1 20 -5.581
1985  1 21 -4.224
1985  1 22 -2.916
1985  1 23 -2.175
1985  1 24 -1.791
1985  1 25 -1.765
1985  1 26 -1.843
1985  1 27 -1.908
1985  1 28 -1.656
1985  1 29 -1.258
1985  1 30 -0.766
1985  1 31 -0.275

1978 - pretty severe -AO but ENSO is also a poor match.

Code: Select all

1978  1 25 -1.081
1978  1 26 -1.248
1978  1 27 -1.574
1978  1 28 -1.660
1978  1 29 -1.443
1978  1 30 -1.492
1978  1 31 -2.075
1978  2  1 -3.037
1978  2  2 -4.213
1978  2  3 -4.574
1978  2  4 -4.846
1978  2  5 -5.291
1978  2  6 -5.026
1978  2  7 -4.474
1978  2  8 -4.040
1978  2  9 -3.982
1978  2 10 -4.329
1978  2 11 -4.769
1978  2 12 -4.927
1978  2 13 -4.761
1978  2 14 -3.820
1978  2 15 -3.382

Edit: 1973 is +AO but you can still look for how a gulf system can work.

[Iceresistance]

Snowing pretty good outside, 19°F

[TeamPlayersBlue]

Does that mean more or less snow?

Means more moisture. Dense HP pushing/displacing air higher, creating lift.

What events can we look at to compare? Only one that comes to my mind is Jan 2018.

Maybe late Jan 1985 or early Feb 1973 had some severe -AO blocking with snow along the gulf. ENSO is a better match for 1985.

This is the daily AO leading to the severe blocking of Jan 1985 and eventual cold grip across the US. -6 which is pretty close to what the forecast is, we're approaching -5



Edit: 1973 is +AO but you can still look for how a gulf system can work.

1989 is another event with intense orographical lift, but it's the outbreak of all outbreaks and it's not even fair to compare to. Thanks for the data! Will investigate comparisons in a bit. Work is really cramping my style today!

[Ntxw]

Means more moisture. Dense HP pushing/displacing air higher, creating lift.

What events can we look at to compare? Only one that comes to my mind is Jan 2018.

Maybe late Jan 1985 or early Feb 1973 had some severe -AO blocking with snow along the gulf. ENSO is a better match for 1985.

This is the daily AO leading to the severe blocking of Jan 1985 and eventual cold grip across the US. -6 which is pretty close to what the forecast is, we're approaching -5



Edit: 1973 is +AO but you can still look for how a gulf system can work.

1989 is another event with intense orographical lift, but it's the outbreak of all outbreaks and it's not even fair to compare to. Thanks for the data! Will investigate comparisons in a bit. Work is really cramping my style today!

1989 from a 500mb perspective is not really impressive. It was just a cold year (some wild HP and cold records in the Alaska Peninsula the Feb earlier in the year). I'm guessing the surface cold was overwhelming.

[Portastorm]

Everyone has been referencing model busts which were too warm ... well, I've got one one for ya ... the NAM busted way too cold today. This morning it was showing temps holding in the upper 40s to near 50 here in Austin. Instead we have rising temps close to 60 degrees now after an initial cool down. Very shallow cold air just along the surface and the frontal boundary is between us and San Antonio. Definitely making for problematic forecasts by computer and human alike!

[cheezyWXguy]

18z hrrr looks like the beginning of a more substantial icing event at hour 33.

To finish out the run...it is definitely substantial. 0.5-0.75” qpf falls as freezing rain across Dallas county

Edit to clarify: ice accumulation totals are only up to 0.25” in isolated areas across the metro, so it would seem the majority of precip the model depicts is falling as “rain at 32”

[GeauxTigers]

I'm a teacher also, and also a hs coach. Our girl's basketball team is supposed to have a playoff game this Thursday night. What are the chances it gets postponed due to road conditions that evening? Or will it get better after the early morning hours and throughout the day? Thanks for your thoughts.

[Haris]

Everyone has been referencing model busts which were too warm ... well, I've got one one for ya ... the NAM busted way too cold today. This morning it was showing temps holding in the upper 40s to near 50 here in Austin. Instead we have rising temps close to 60 degrees now after an initial cool down. Very shallow cold air just along the surface and the frontal boundary is between us and San Antonio. Definitely making for problematic forecasts by computer and human alike!

Maybe the euro isn’t that bad afterall? Lol. But yeah for sure a big bust. Hoping this is a fluke

[bubba hotep]

Everyone has been referencing model busts which were too warm ... well, I've got one one for ya ... the NAM busted way too cold today. This morning it was showing temps holding in the upper 40s to near 50 here in Austin. Instead we have rising temps close to 60 degrees now after an initial cool down. Very shallow cold air just along the surface and the frontal boundary is between us and San Antonio. Definitely making for problematic forecasts by computer and human alike!

Currently 61F at Camp Mabry vs 34F at DFW.

[SoupBone]

Weather Underground is bullish for Houston getting snow starting 10am Monday morning. Certainly, they are not an employer of Wxman.