DFWWeather

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.

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.

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.

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.

National Weather Service office in Fort Worth is issuing Winter Storm Watch this afternon for pretty much all of North Texas, including the DFW Metroplex.

The front came through Lubbock and the temperature fell 30 degrees in under an hour. The overnight low tonight there is forecast to be 9°F and they are already at 7°F, which was not forecast. This front is busting forecast and model numbers and you could easily take 5 degrees off of those. This front means business!

The op models finally catching on to the severeity of this cold air outbreak this morning. I expect them to continue trending colder. This will not be a repeat of February 2021, nor will it be a repeat of December 1983 or December 1989. We will not be that cold, nor will the longevity of this cold spell approach those levels. I expect temps below freezing for 2 to 3 days now max at DFW. At the coldest point (Christmas Eve or Christmas Day) temps should be 8°F to 11°F around DFW. Anytime temps get to 10°F or lower in this region is "severe cold" and Hard Freeze Warning will likely be needed. Arctic front should arrive on Thursday, if not sooner with crashing temps behind it. Likely all of North Texas will be in the teens on Friday morning. The Canadian ensembles have the best handle on temps with this.

The operational models are not doing very well on this cold air outbreak. They are not catching the cold air damming common with these into Texas. Their ensembles however are. The chances of any snow with this look very low. This not a setup for a significant snow event in Texas, especially around DFW. I still say upper single digits to lower teens to the I-20 corridor. Upper teens possible to around 20 in Houston, and 20s into LRGV with this.

Today's operational runs of the GFS, ECMWF, CMC really backed off on the cold into Texas next week (not hadling the low level cold air into the Southern Plains, nor accounting for cold air damming). Actually, doing some crazy stuff. However, the ensembles still have a severe cold snap into Texas. The 18z op GFS starting to catch back on to the Texas intrusion. Interesting to note, a couple of ensembles members of the ECMWF and GEFS have DFW at 3 below zero for a low on Christmas. Don't think it will be that cold, but singles digits to I20 even in DFW, teens below zero in the panhandle and freezes to LRGV all very possible with this. Don't think it lasts longer than 3 to 5 days max.

0z op models seem to be all over the place this morning with cold and magnitude next week. However, nearly all the ensembles from the CMC, ECMWF, and GFS are showing multi-day subfreezing temps at DFW with averages now down in the teens for lows. Several members show us getting to the single digits. If the GEFS (ensemble) 500 mb pattern is correct (below) Texas will take a direct hit. This will put challenges to the power grid. I think freezes all the way into LRGV look likely with this.

Very much agree with you on this. Seems all the teleconnections are pointing to an Arctic outbreak. How severe will it be and will it affect Texas directly like in the two years you mentioned are the questions? With a higher than usual chance of snow or ice in our around Christmas this year, we may be looking at temps as cold as 10 or colder before all said and done at DFW. I don't think we will get as cold as Febrary 2021, nor do I think this will be as protracted as December 1983 though, at least not yet.

I've lived through several terrible ice storms in DFW. I'm not old enough (thankfully) to remember the event that occurred in Fort Worth in late January early Febraury 1949. 4 days of not-stop freezing rain and drizzle caused ice to accrete 7 inches thick. Also our temp dropped to -2°F with that event. That is the worst ice storm in Metroplex history.

I meant in relation to the GFS. It does a much better job of handling low level cold air. I bet the temp adjust on the 3km as it is just coming into range. NAM always starts off a little warm when coming into range then adjusts.