DFWWeather

On 2/4/2025 at 7:55 AM, Stx_Thunder said:

Not seeing any strong signal for another Arctic air intrusion or outbreak in the state for the rest of the season. The next few frontal airmass intrusions are mostly just Canadian origin with the real cold air firmly staying north/east.

-AO does not always translate to Arctic air intrusion nor outbreak (even during winter).

I apologize if I have upset you, but you absolutely did say no more Arctic air for the rest of the season. See your post above from Feb 4th. All I did was disagree with you. I use the word 'extreme' because that is the term the NWS uses. The Extreme Cold Warning is not just for wind chills, it is also issued for the prolonged duration of subfreezing temps, and the threat of temps falling to 10 or lower or for high temps failing to reach 20. For our area, the latter is considered severe cold. In this case, there is a threat some areas around the DFW Metroplex will get to the single digits with this and for a prolonged duration subfreezing temperatures, not to mention wind chills as cold as 10 below zero.

I was just pointing out that not even South Texas is escaping the cold. Anytime it freezes in LRGV it is a big deal. That is why Marshall J. McFarland came up with the McFarland signature that recognized prominent 500mb pattern features that lead up to freezes deep into Texas. The key to getting Texas cold is the position of the west coast ridge, if it is along the west coast, or off-shore up over Alaska. The latter has historically produced some of Texas' biggest cold shots and is a key element in the McFarland pattern. Though the current outbreak was not a result of a McFarland.

19 hours ago, Stx_Thunder said:

 

The models are only showing 1 or 2 mornings, of "extreme" cold in DFW.. Not all day.

It's been projected like that for some days now even on Euro.

I guess we just have a different idea of what "extreme" cold looks like for DFW. The NWS has issued an Extreme Cold Warning for the area. Temps are not forecasted to get above freezing until Friday with a shot of getting below 15°F on Thursday morning and wind chills below zero at times tonight and possibly tomorrow night.  Subfreezing temps all day this late in the year is quite "extreme." We are talking temperature anomalies of 25 to 30 below normal for a couple of days. I do not know what else you need to have...Feb 2021? What happened in Feb. 2021 is a once in 30 year event in DFW. You said before we were done with the Arctic air for this winter. I said the pattern would deliver, that cold air loves to push in this type of pattern, that it would likely be DFW's coldest air of this winter, and that is exactly what is happening.

I might also add they are expecting freezes in the LRGV with this. Freeze Watch in effect for Laredo, Tx right now over to Corpus.

11 hours ago, Stx_Thunder said:

'Pretty certain now the next winter episode this coming week is going to be a temperature (only) story. And even then, mostly a glancing arctic blow with mainly the chill values the issue in NTX. Temps in DFW & south could even get above freezing on GFS for highs with sunny skies also (right after frontal passage the night before), Wednesday afternoon, and stay above freezing after Thursday morning with WAA cloud cover returning Thursday night ahead of a late week trough. Which definitely lowers the nocturnal freeze threat.

Looking ahead, I would not say winter is necessarily done for after this coming week as the AO may go back into another formidable negative phase around mid March. More of the recent CFS data is also depicting lots of below normal temps across the Plains, and even in our state starting near March 10th - 20th. Which is likely an indicator of that.

Also, the already weak LN is starting to fall back toward neutral ENSO territory (as it typically does nearing spring). Not saying it would be as cold as this upcoming week, but I definitely wouldn't expect an all-warm & dry March this time around, the way things have been going lately coming into later February now. As I've seen over the years, we're typically more susceptible to chilly/wet 'spring break' season spells from these weak EN/LN and neutral ENSO winters.

This is not a glancing blow of Arctic air with a ~ 1050 to 1055mb high building down the plains. This is a direct shot. KDFW has a the potential at getting below 15°F with this on Thursday morning with windchills dangerously cold for North Texas. The NWS has issued a Extreme Cold Watch which will likely get upgraded to a warning. I agree precip will be light, but there is a signal in the models for freezing drizzle/mist beyond 4pm Tuesday into early Wed with temps falling well down into the 20s. KDFW is forecast to remain below freezing for at least 36 hours. The deterministic GFS is out to lunch on temperatures and has been performing terribly all winter long for DFW, and doesn't even agree with its own ensembles which are in the teens for KDFW. I think that model just cannot see cold air anymore and there is an extreme warm bias to it.

Do not disagree that March may be on the colder side.

36 minutes ago, aggiegeog said:

The cold next week could shatter records especially if we do get some snow. North of I-20 may see -0s with widespread 0s. Record low mins and record low maxes are likely to fall as this event is just after the worst of 2021. Breaking 1978 and 2021 records is big.

This pattern is one that doesn't typically bring North Texas a lot in the way of wintry precipitation. Looking at latest 12z data on all the models, there seems to be a trend of the wave moving east rather quickly being drier overall. Thus, whatever falls will be very light, but I'm starting to think it won't be much of anything. I don't see the type of cold you are talking about without decent ice/snow on the ground, and none of the models suggest amounts would be that much. I think DFW has a shot of getting below 15 with this, maybe down to 8 to 12 with a bit of snow/ice, but it won't anything like 2021, at least for DFW. 10 degrees would necessitate an Extreme Cold Warning for our area though.

Currently, 24°F at DFW this morning with still room to fall. Quite the forecast bust on this airmass as most forecasts had us 27°F to 29°F this morning for a low. The ECMWF has been doing exceptionally well this winter for DFW for temperatures and had us this morning in the low 20s forecasted all week. It should be noted the ECMWF and all of its ensemble members are forecasting 1050+ mb Arctic high to plunge out of Canada into the plains and down into Texas by middle of next week with the coldest air of the winter. Temperatures will easily get into the teens with this (though the deterministic and several ensemble members are suggesting temperatures into the single digits). The other notable thing is the potential of precipitation Tuesday night into Wednesday which would likely be frozen. The Canadian also has signal for precip as does the GFS, the GFS is very light and further east. So I cannot entirely discount the colder ECWMF scenario if we get snow/ice. Looking at our records, for DFW to not have at least one day per winter season dropping below 20°F is actually pretty rare with less than 20% percent of our winters actually failing to get that cold.

4 hours ago, aggiegeog said:

We are looking at a solid chance for an icing event across N TX mid week next week. The cold air initially arrives this weekend with further pushes through the week. Some chance for this to a be an ice storm for a large portion of the state, but we won't know how deep into the state until this weekend. Good chance that the remainder of the month stays cold with substantial blocking over the Arctic and well placed ridging out west. Enjoy these last couple warm days as those will be unlikely north of I-10 after this weekend until March.

Completely agree. I noticed how the FWD NWS has now started to note the potential for low temps in the low/mid 20s for DFW later next week in their AFD. Some of the models/ensembles are showing that temps could even get into the teens. We all know that in this type of setup, the synoptic models do not catch the low level cold air well at all at this time range. That kind of Arctic air loves to push, even against zonal flow in this type of setup. Now whether there is enough moisture at the time of coldest temps for significant icing remains to be seen. While noting the cold bias of the Canadian, its ensembles averages are pretty good, and those are showing the colder potential with this pattern.

1 hour ago, Stx_Thunder said:

No real complaints about this ongoing warm/ridging pattern (especially how chilly January was overall).

Not seeing any strong signal for another Arctic air intrusion or outbreak in the state for the rest of the season. The next few frontal airmass intrusions are mostly just Canadian origin with the real cold air firmly staying north/east.

And of course, Canadian model is doing its usual extreme bias junk. Euro & GFS aren't anywhere near as cold in the coming weeks. And their ensembles are starting to trend warmer for later February. Though it'll probably be cooler overall than of late, and going into March. Considering also the AO looks to trend back into a possibly more persistent negative phase for later February.

-AO does not always translate to Arctic air intrusion nor outbreak (even during winter).

Strongly disagree with you. I suggest going back and studying past examples of this same setup. February 1989, February 1996, December 1983 (yesterday 12z ECMWF 500mb closely resembled that), and yes February 2021 as just a few examples. It is known thing to watch for when you see the ridge shift off the west coast and up over Alaska for cold air down into the plains and Texas. MJO moving to phases 7&8 which are cold phases, -EPO,  -WPO, -AO, potential -NAO (not sold on that one yet) developing all point to colder air flooding the pattern. Their will be more of southeast ridge that will fight this, but the cold air loves to push in this scenario, and usually down into Texas as opposed off to the east. I'm not saying that we will get anywhere near as cold as those event, just that the pattern is similar and can translate to temperatures well below normal. What is common on these types of setups is usually the models don't catch on until we get right up on the event.

We got a negative EPO, negative WPO, negative AO, and possibly a negative NAO developing next week. Ridge this time positioned off the west coast up over Alaska (big difference this time around as opposed to along the west coast). This time around we may have more of a southeast ridge that will fight. This cold shot would be centered down the plains as opposed to further east. This setup is Katy bar the door cold for Texas. Look late next week to around Valentines Day for a flip to much colder. ECMWF is catching on but having trouble, as it did in Feb 2021 until we got right up on the event. The GFS is also seeing something. While I don't think we will get as cold as Feb 2021, I do think this is going to be Texas' coldest part of this winter coming up.

Analysis of 12z data shows these temps at H85 at DFW at the coldest point of this Arctic air outbreak:

ECMWF: -11°C, Canadian: -14°C, GFS: -11°C, NAM: -13°C

And shows this for actual lows at coldest point:

ECMWF: 22°F, Canadian Ensemble mean: 11°F (deterministic way too cold at 9°F), GFS MOS: 15°F (actual raw number on deterministic GFS is 26°F which way too warm), NAM MOS: 15°F, UKMET and ICON both at or above 20°F

The actual forecast low by NWS is 21°F.

In past experience with H85 temps -10°C or greater actually translates to mid teens at DFW Airport. Something is wrong, either the H85 temps are wrong or forecasted surface temps on the models and NWS are too warm and are going to bust. The NAM MOS seems the most reasonable to me on temps which does superiorly with low level cold Arctic air in North Texas. Urban heat island usually is not as much an issue in Arctic air as with radiational cooling as we noted quite clearly in February 2021.

1 hour ago, aggiegeog said:

If ICON and Canadian are close to right then we will see a widespread powdery 6-12" of snow on Tue. Very high ratio snows with a 10k+ foot DGZ and surface temps in the teens. Won't take much QPF to get a good amount of snow.

For DFW, a dusting to an inch at best if we see snow at all. Concerns of quality moisture making it this far north. All models forecast H85 temps to below -10°C. In my experience, this translates to widespread lows in the low to mid teens, even into the heart of the Metroplex. The ECMWF, UKMET, and GFS deterministic models look way, way too warm with lows barely below 30°F on the GFS and only in the low 20s on the ECMWF and UKMET. Highs will struggle getting above freezing Sunday through Tuesday, if they do at all. Note the ICON and the Canadians show lows in the single digits. 

Looks like DFW is in for another blast of Arctic air, perhaps Siberian in origin. This one looks much colder than last week as Texas might take a direct hit. It should arrive this weekend. The 12z ECMWF has H85 temps as cold as -17°C over the Metroplex and similar on Canadian. That would definitely bring concerns of temps getting down to the single digits even into the heart of the Metroplex. There is also the possibility we could stay below freezing for a day or two. However, the models are starting to trend drier with this and don't see much wintry precip with this outbreak. I don't think we will get as cold as February 2021 without ice and snow.

48 minutes ago, vwgrrc said:

Good call here. Both 12z NAM and HRRR came in notably warmer than yesterday. DFW is basically a cold rain until later this evening if that holds true. a bit disappointing but at least there's still plenty of snow overnight, hopefully!

DFW has a current temp of 30°F (fell from 36°F earlier this morning since precip began) with moderate sleet coming down. It will be hard for temperatures to rise if we saturate out below freezing with on going precip. Could be more significant sleet as noted by NWS before change over to all snow later.

The 12z ECMWF ensemble 51 member mean average snowfall for DFW is 8 inches. Remarkable! Its temps are significantly colder than the NWS office. It has a low of 20 for Friday morning and 18 for Saturday morning. All day Thursday it keeps temps between 30 and 33.

The 12z GFS and Candian are upping totals for DFW. Surprisingly, the 12z NAM has increased its totals too. Candian/RGEM going for record breaking snows at DFW 12 to 14 inches. Wonder what the 12z ECMWF will have?

The NWS has upgraded the Winter Storm Watch to a Warning. Going with general 2 to 4 inches with isolated totals 6 to 9 inches. Problem is their forecast temps I feel are much too warm for anything but rain or snow melting on impact. They have a low overnight Thursday into Friday of 34 at DFW. Most models I'm looking at are generally between 30 and 32 during this period.

18z ECMWF and ensembles are again being consistent on a 4 to 8 inch snowfall across the Metroplex.

The 0z deterministic ECMWF cut its snow in half for DFW, however, the 6z did not disappoint, nor do a majority of the ensemble members of both runs. The 6z NAM is also not disappointing. I have noticed, now that we are getting in range of the hi-res models, that much of the snow in the Big Country into West Texas is much less. The GFS is significantly warmer than the NAM, ECMWF, CMC, and their ensembles. Even though it has accumulating snow (much less), but should really only be a cold rain given its temps. I see a reinforcing surge at H85 of cold air coming into the state tomorrow and again behind the departing system.  I think the 6z ECMWF temps look reasonable through Saturday.

33 minutes ago, vwgrrc said:

Yea. 18z GFS seems confirming that drier+warmer trend actually. ICON isn't the best but that NAM run looks really outlandish. This still has a chance to become a cold rain even for NTX looks like. 

The GFS in general is warm compared to all the other models. The 18z GFS still gives the Metroplex a decent snow event. I would wait and look at the 0z GFS before saying their is a trend. Much more ensemble support with it. Though there was a drier note on the 12z GFS ensemble spread compared to its 0z. NAM is usually a good model for winter storms. The ECMWF has been very consistent with this storm. 

7 hours ago, aggiegeog said:

Becoming increasingly likely that this is an all time type event for DFW. Definitely a top 10 event for them and maybe a top 3. Those caught in convective bands could see over a foot.

I certainly agree with you. This will be one for the record books should the forecast hold. Widespread 5 to 10 inches with isolated higher amounts for the Metroplex. The event will rival the February 2010 event (though this looks colder), January 1964, and February 1978. Low temps will crater to the upper teens on Saturday with that much snowfall. This will disrupt travel not only Thursday/Friday, but likely into the weekend as well.

35 minutes ago, Stx_Thunder said:

With respect to temps, latest 12Z NAM-Hires this morning (covering Monday now) is not looking impressive with the incoming cold airmass. I would even say by most means.

Still showing actual temps getting down to around freezing (32 F) near the coast early Monday (so freezing drizzle/rain potential still there as well), but even NTX isn't looking too cold either. And even that model shows some substantial warming there too, back closer to the freezing mark Monday afternoon.

At this point, it's looking more like a very chilly airmass for TX, rather than an actual cold/Arctic one.

The 12z NAM is showing a high of 22°F for Monday and a low of 11°F for DFW for Tuesday morning. Pretty Arctic I'd say, which is the source region of the airmass.

2 hours ago, Stx_Thunder said:

Was reading that Euro is trending drier in this morning's Austin/San Antonio NWS AFD because they were also concerned about winter precip in that forecasting region next week. There's just too many snow (and tornado) fans on this wx site.

They're currently going around 20 F for lows Monday night (WC in single digits which'd be fun), around San Antonio. Either way, it'll definitely be chilly in all of the state for sure next week. NAM of course, will spill the beans when it gets close.

But they're talking now that the intruding cold could stay for an extended period. I don't think we'll have an intensity repeat of TX February 2021 as the more intense ones are often associated with LN winters. But below freezing temps even just in the mid-lower 20s down here in STX for about 10 hours straight would be a pain in the butt for the pipes. With those temps, lots of peoples main lines busted around Corpus during the Feb 2021 freeze causing the water pressure to drop for everyone in the city.

It normally never gets that cold this far south in the state (to note on here). Especially near coast.

The ECMWF suite this morning has trended a bit drier even for DFW, but it is still outputting enough QPF that it would cause major travel impacts if it were to verify. It should be noted that the Canadian is also showing QPF for Sunday night into Monday for North Texas. Much of it on both models would fall as freezing rain and/or sleet, not as much as snow given how shallow this airmass will be. The GFS still has the same trailing wave but it is further north and east with it and has been all over the place with both the cold and the wave compared to the other two models with very little run to run consistency.

The ECMWF is bringing the front into DFW Saturday afternoon. Significantly earlier than the rest of the models. Be interesting to see what the NAM says about that.

It is conceivable in North Texas, including DFW Metro, that temps will be below freezing 36 to 48 hours. The big concern here is it is looking more likely temps will fall into the single digits with this even into the Metroplex itself with some of the outlying areas falling to near 0°F.

You should see the ECMWF (including control and most of its ensembles), much more bullish than the GFS on wintry precipitation for DFW and has been for several runs. The Canadian not so much. Temperatures have markedly decreased this morning on all models for this Arctic air intrusion. DFW has a reasonable shot of falling below 10°F, especially if we get snow/ice. The Oz ECMWF deterministic this morning is down to 5°F for DFW, which is impressive for that model this far out. It'll be interesting to see how the NAM handles this.

18 hours ago, Powerball said:

Now that the 90s & 100s seem to be mostly gone for good (for sure after this Thursday)...

Revisiting this post, it's crazy how many records we set or tied this Summer, for it being mostly backloaded.

1980 and 2011 both still reign as kings, but this year was definitely a solid runner up behind the 2 by most measures.

And that doesn't even speak to September. I suspect JAS period was also amongst the warmest on record for DFW, similar to how MJJ was in 2022.

Nice write up summary about the summer of 2023 for DFW.

September 2023 came out to be the second hottest on record for DFW behind 2019* as the hottest. The avearage temp was 84.6°F. We did not fall below 60°F. There are only about 12 other years I think where we didn't fall below 60°F in September. Nearly all of the following winters were warm winters. So at this point, I am growing skeptical on a below normal winter like a lot of forecasters are suggesting just because of the El Niño. Even if you look at the top ten hottest September's on record, I believe there is only like one year where the following winter was cold. So odds are not very good that the winter of 2023-24 will be colder than normal, despite it being an El Niño.

*2019-2020 as we can all remember was also a warm winter with no snow or ice.

15 minutes ago, vwgrrc said:

I'm actually a bit shocked they issued the warning at this point given the latest HRRR isn't that aggressive for tomorrow and the amount is *only* up to 0.25. IMO December 2013 was much worse. 

I'm not sure the HRRR has been the model of choice through this event. I believe the NAM and Canadian (both its hi-res, operational Synoptic, and ensembles) have been outperforming nearly all of them. The concern here is the depth of the warm air aloft will deepen as the warm air advection process ramps up as the upper low approaches. This will almost gurantee the next round precip will be much less sleet and more freezing rain. 1/2 inch of freezing rain is much worse than sleet. Combine that on top of the sleet and it will be total ice skating rink with wet water on top of ice before it freezes. What a mess! At least with the cobblestone ice, you did have "some" traction. So, I am not surprised the warning was upgraded at all. The December 2013 was worse farther off to the northwest of the Metroplex due to its longevity in that region (what 5-6 days vs the 2 1/2 in the Metro?) and it was all sleet, with very little freezing rain. I probably should have worded it may potentially surpass the those two events if the forecast holds.

The Ice Storm Warning is truly a rare issuance in this region. This generally is not issued unless ice accretion totals are expected to be 1/2 inch or greater, which is severe icing. If forecast holds this, combined with this 1/2 inch sleet already on ground, is turning out to be the worst ice storm this century for the western part of the Metroplex. I doubt very seriously temperatures will move far enough above freezing to improve road conditions, especially in this area, until late Thursday or possibly into early Friday. This surpases the December 2013 and February 2003 events.