Texas Winter 2021-2022

[Haris]

Case in point Bubba, the fam and I were in San Marcos during the "no catch" Dez Bryant game in January several years ago. The precip started as freezing rain but over time the deeper rain came in and melted the ice during the day with a temp close to 32. We made it home to Dallas no prob that evening.

Historically it needs to get down to 27-28 for legit ice accretion. Above that, and it's poles, fences, cars, tree limbs somewhat, etc/\

[txtwister78]

This is why I’m not really concerned much about it. I’m fairly confident the cold is coming and the SE ridge isn’t going to win out. Models do this time and time again with these shallow Artic airmasses. How many times have we seen this..

Difference is you have a positive AO/NAO so the tendency is for the cold to remain a bit more bottled up I think with that setup.... there are signs that we may get a secondary push late in the week that the models didn't have just two days ago, but how much cold is left is also suspect at that point. The other aspect is temps are going to be really warm out ahead of the shallow cold air as a result of the stout SE ridge (-PNA) so this is not a layup as some might think in my opinion.

I do agree models are probably not handling the shallow nature of the cold as it drains into the state, but I don't think this is one of those scenarios where we have an arctic HP that just overwhelms the pattern and the cold barrels into the state. I think this is going to be more gradual and as a result that can make forecasting winter precip tricky.

Hi Res 5-10 deg F colder Tuesday, this airmass is even shallower than the one in early Feb….going to give Globals fits

I don't see that much of a difference quite honestly with the NAM at 84 hours out compared to the GFS or Euro. Definitely could be some timing differences as it relates to the boundary to account for surface temps being "colder" by a few degrees but I don't see anything yet that shows wild variation between the globals and the NAM. Maybe that changes in the next day or two but nothing significant showing up just yet.

[Cpv17]

Difference is you have a positive AO/NAO so the tendency is for the cold to remain a bit more bottled up I think with that setup.... there are signs that we may get a secondary push late in the week that the models didn't have just two days ago, but how much cold is left is also suspect at that point. The other aspect is temps are going to be really warm out ahead of the shallow cold air as a result of the stout SE ridge (-PNA) so this is not a layup as some might think in my opinion.

I do agree models are probably not handling the shallow nature of the cold as it drains into the state, but I don't think this is one of those scenarios where we have an arctic HP that just overwhelms the pattern and the cold barrels into the state. I think this is going to be more gradual and as a result that can make forecasting winter precip tricky.

Hi Res 5-10 deg F colder Tuesday, this airmass is even shallower than the one in early Feb….going to give Globals fits

I don't see that much of a difference quite honestly with the NAM at 84 hours out compared to the GFS or Euro. Definitely could be some timing differences as it relates to the boundary to account for surface temps being "colder" by a few degrees but I don't see anything yet that shows wild variation between the globals and the NAM. Maybe that changes in the next day or two but nothing significant showing up just yet.

https://images.weatherbell.com/model/gfs-deterministic/tx/t2m_f/1645272000/1645596000-4XqhLpSg4TI.png

https://images.weatherbell.com/model/nam-218-all/tx/t2m_f/1645293600/1645596000-4hK94OCFITo.png

[txtwister78]

Yeah I don't think anyone doubts that temps will be below normal relative to averages for this time of the year later next week (avg highs in the lower to upper 60's & lows in the lower to mid 40's generally across the state). The question is how cold at this point and that's definitely still up in the air.

[Cpv17]

Yeah I don't think anyone doubts that temps will be below normal relative to averages for this time of the year later next week (avg highs in the lower to upper 60's & lows in the lower to mid 40's generally across the state). The question is how cold at this point and that's definitely still up in the air.

And it should continue into the first week of March.

[txtwister78]

Yeah I don't think anyone doubts that temps will be below normal relative to averages for this time of the year later next week (avg highs in the lower to upper 60's & lows in the lower to mid 40's generally across the state). The question is how cold at this point and that's definitely still up in the air.

And it should continue into the first week of March.

Cool

[Cpv17]

Yeah I don't think anyone doubts that temps will be below normal relative to averages for this time of the year later next week (avg highs in the lower to upper 60's & lows in the lower to mid 40's generally across the state). The question is how cold at this point and that's definitely still up in the air.

And it should continue into the first week of March.

Cool

Okay. The CPC has placed a good portion of Texas in a moderate risk area for below normal temps along a slight risk for the rest of the state. This also includes a 60 to 80% chance for below normal temps across the state. The last time they were that aggressive was in early February and it got pretty cold. I understand what you’re saying about the AO/NAO but I can’t just ignore what the CPC is saying. Not saying you’re ignoring it either but I get the feeling you’re not putting much stock in them.

[Haris]

Well the darker CPC colors, means increasing chances of simply below normal temps. Not necessarily more and more colder per say. It’s a probability map. So it could be 45 instead of 29 but the graphic would show the same depending on the seasonal norms at the time.

I think what twister is arguing is the specific intensity of the cold May not be too much and more like a brief few days in the 30s and 20s.

[Cpv17]

:uarrow:

Well the darker CPC colors, means increasing chances of simply below normal temps. Not necessarily more and more colder per say. It’s a probability map. So it could be 45 instead of 29 but the graphic would show the same depending on the seasonal norms at the time.

I think what twister is arguing is the specific intensity of the cold May not be too much and more like a brief few days in the 30s and 20s.

Correct but more times than not (from what I’ve seen regarding the CPC) is that when they do issue the darker colors it usually does get pretty darn cold. But technically, yes, you’re correct.

[orangeblood]

Difference is you have a positive AO/NAO so the tendency is for the cold to remain a bit more bottled up I think with that setup.... there are signs that we may get a secondary push late in the week that the models didn't have just two days ago, but how much cold is left is also suspect at that point. The other aspect is temps are going to be really warm out ahead of the shallow cold air as a result of the stout SE ridge (-PNA) so this is not a layup as some might think in my opinion.

I do agree models are probably not handling the shallow nature of the cold as it drains into the state, but I don't think this is one of those scenarios where we have an arctic HP that just overwhelms the pattern and the cold barrels into the state. I think this is going to be more gradual and as a result that can make forecasting winter precip tricky.

Hi Res 5-10 deg F colder Tuesday, this airmass is even shallower than the one in early Feb….going to give Globals fits

I don't see that much of a difference quite honestly with the NAM at 84 hours out compared to the GFS or Euro. Definitely could be some timing differences as it relates to the boundary to account for surface temps being "colder" by a few degrees but I don't see anything yet that shows wild variation between the globals and the NAM. Maybe that changes in the next day or two but nothing significant showing up just yet.

https://images.weatherbell.com/model/gfs-deterministic/tx/t2m_f/1645272000/1645596000-4XqhLpSg4TI.png

https://images.weatherbell.com/model/nam-218-all/tx/t2m_f/1645293600/1645596000-4hK94OCFITo.png

That NAM freezing line is 80-90 miles south of the GFS, big difference with huge implications when it comes to freezing rain. Particularly involving a metroplex with over 7 million people

[txtwister78]

:uarrow:

Well the darker CPC colors, means increasing chances of simply below normal temps. Not necessarily more and more colder per say. It’s a probability map. So it could be 45 instead of 29 but the graphic would show the same depending on the seasonal norms at the time.

I think what twister is arguing is the specific intensity of the cold May not be too much and more like a brief few days in the 30s and 20s.

100%

[txtwister78]

Hi Res 5-10 deg F colder Tuesday, this airmass is even shallower than the one in early Feb….going to give Globals fits

I don't see that much of a difference quite honestly with the NAM at 84 hours out compared to the GFS or Euro. Definitely could be some timing differences as it relates to the boundary to account for surface temps being "colder" by a few degrees but I don't see anything yet that shows wild variation between the globals and the NAM. Maybe that changes in the next day or two but nothing significant showing up just yet.

https://images.weatherbell.com/model/gfs-deterministic/tx/t2m_f/1645272000/1645596000-4XqhLpSg4TI.png

https://images.weatherbell.com/model/nam-218-all/tx/t2m_f/1645293600/1645596000-4hK94OCFITo.png

That NAM freezing line is 80-90 miles south of the GFS, big difference with huge implications when it comes to freezing rain. Particularly involving a metroplex with over 7 million people

Right now, 0z NAM (and 18z for that matter) are dry at 84 hours out, so definitely no danger (at least at that range) of any frozen precip for the 7 million people. When compared to the 18z GFS, which had surface temps right at or a degree or two above freezing during the same window (also dry btw at 84 hours out) I think the NAM is a tad bit colder but certainly not by 10 degrees (few degrees is what I saw). I think up in that region though, it's not really a question of whether temps hit the freezing mark. I think they will at some point, but as mentioned before roads will be very warm and unless temps fall into the 20's, I think this won't be as significant as the early Feb event and so I think that's great news for that area.

My overall point earlier was across the state as a whole the NAM is not really showing some huge contrast in temps that would lead anyone to believe the globals are out to lunch yet in terms of their handling of the shallow arctic airmass. That may very well happen as we get closer but so far, I think models are pretty close with respect to the strength/progress of the cold pushing into the state. Right now, I actually think the 0z NAM is a bit slower with the front than the 18z GFS was (particularly across SC TX).

[txtwister78]

Man look at that recovery in temps on the 0z ICON now for Thursday....continues to show very little in the way of frozen precip for most of the state next week.

[Cpv17]

The 0z Euro has a 1047mb high in Oklahoma on day 10

Probably won’t happen but I don’t want winter to end yet.

[orangeblood]

Noon Wednesday

Gfs


Vs

NAM


This is a significant difference in temps for that time frame. Other short range guidance already breaking out precip ATTM, this has major implications for this forecast particularly when you have 28 Deg F across DFW vs 33-34 on GFS. Austin almost down to 32 F on NAM while GFS showing 48 F

[cheezyWXguy]

Yep, if the NAM is correct, forecast temps Wednesday are going to need to be dropped almost 10 degrees. Also, glad to see it was to change to sleet in the metro pretty quickly

[txtwister78]

The NAM (for the first time in its 6z run) delivers cold further into the state on Wednesday compared to the globals no question, however it's the only short-range model (at this point) to depict that. The RGEM is significantly "warmer" further south as is the HI-RES WRF FV3 (only 60 hours out).

The NAM does have a good track record when dealing with shallow airmasses so it's important to watch to see if that becomes a trend in future runs and if any other model begins to follow. Important to note though (not mentioned above) and that is the NAM is showing very light mixed frozen precip across mostly central TX which would be great news for those further north if its surface temps are indeed accurate.

[bubba hotep]

Pretty much all models now show a period of freezing rain/drizzle for DFW. Does FWD go with an Advisory or a Watch? It looks like the freezing rain accretion to 1/4 criteria will be close to being met, esp. if surface temps are lower like on the NAM.

[Haris]

Pretty much all models now show a period of freezing rain/drizzle for DFW. Does FWD go with an Advisory or a Watch? It looks like the freezing rain accretion to 1/4 criteria will be close to being met, esp. if surface temps are lower like on the NAM.

My hot take is we see temps colder than even NAM. Just with this last front this week, NAM even had to adjust colder and colder within 48 hours. Upwards of 10 odd degrees. Every model even icon was off. I think the biggest question again is how much moisture for you guys. At a minimum though probably advisory since freezing drizzle for now seems to be a likely up N

[Portastorm]

The NAM (for the first time in its 6z run) delivers cold further into the state on Wednesday compared to the globals no question, however it's the only short-range model (at this point) to depict that. The RGEM is significantly "warmer" further south as is the HI-RES WRF FV3 (only 60 hours out).

The NAM does have a good track record when dealing with shallow airmasses so it's important to watch to see if that becomes a trend in future runs and if any other model begins to follow. Important to note though (not mentioned above) and that is the NAM is showing very light mixed frozen precip across mostly central TX which would be great news for those further north if its surface temps are indeed accurate.

And the 12z run for the NAM continues to raise an eyebrow or two. While it performed poorly IMO with the last strong front it is, as you say, very good normally with shallow cold fronts in Texas. It’s showing surface temps some 20 degrees colder than what’s currently forecast for example here in Austin at 0z Thur (6 pm Wed).