DFWWeather

From FWD: Heavier intensity precipitation will start after dark and should primarily be sleet. We'll continue with moderate sleet from 02Z through the overnight, however there is some concern that we could see a quicker transition to snow if lift is stronger than anticipated. If that occurs, then snow could be heavy at times. For now, we'll continue to monitor this and carry a snow/sleet mix after 10Z with a transition to all snow by 14Z. Precipitation should start to taper off around midday Sunday. Overall the vertical column has been cooling much quicker than models have forecasted. If we can get the change over to snow and with temps in the teens tonight snowfall ratios will be extremely efficient. Even if it stays sleet your looking at 4:1 or even 5:1.

Metro may be primed for more snow this evening with 20:1 ratios looking probable as temps will be in the teens shortly.

Arlington side roads now completely iced over. KDFW down to 21 and getting moderate to heavy sleet.

KDFW now down to 23°F racing toward the teens. Grass starting to get covered in sleet. The second wave tonight may producer way more snow than thought and higher end ratios. Any thoughts? I can say we are out of the heavy ice/freezing rain accretion zone.

Absolutely, this will be a sleet dominate storm. There could be 0.10 to 0.25 ice accretion. I'm more concerned with higher sleet totals than what FWD is advertising, especially with the potential for thunder sleet or convective sleet. There should be some snow on the back end as the entire column cools.

I have a feeling the 1 to 3 inches of sleet forecast by FWD might be a tad underdone given what I am seeing in the models and the potential for convective sleet.

Very interesting read on afternoon AFD from FWD, discussing thunder sleet.

12z 3km NAM is burying KDFW in 5 to 6 inches of sleet.

Today's 0z data came in quite a bit warmer overall. Looking back at POR and reconstructed anecdotal data back to 1785, there has never been two subzero readings at DFW in a five year window. That would be unprecedented if we did. That is a 25 to 30 year outcome at best. So my expectation is that we stay at 5 or above at coldest point Monday for KDFW. Still respectable cold though, but still acknowledging a non-zero risk of falling below 5. Colder spots could get that cold. Despite many forecast, we are not going to get above freezing on Monday if we start that cold with significant snow/sleet, especially with a northerly wind component. So significant improvement may not be had until Tuesday afternoon and even then I think we will stay below 40, so risk of problems Wednesday morning from refreezing is likely if we get at least 3 inches of sleet. NAM is burying us in 5 to 6 inches of sleet, but I think it is missing the change over to snow on the back end.

12z GFS showing 0 at KDFW and ICON showing -2 and Canadian at 1

Norman has upgraded their FA to a Winter Storm Warning. I'm sure other offices will follow sometime today. Most guidance is clustered around ~2.00 QPF for DFW. FWS has upped its ice accretion to 0.25 to 0.50 and over east Texas 0.75 to 1.00. This is squarely in Ice Storm Warning criteria and I wonder if that is where they are leaning for part or all of the area. I still think for DFW sleet will be the predominate precipitation form.

Actually, the upper low is slowing down a bit and models are converging on that. FWD NWS is upping their timing on the cold air and beginning impacts in the afternoon Friday. This still looks like a predominately sleet storm with snow on the back end. An Extreme Cold Watch has also been issued.

Diving into this morning's 0z data. It is even colder, now suggesting DFW could potentially stay below freezing through Wednesday or Thursday next week with potential another shot of Arctic air on Friday. QPF has increased across all modeling. Single digits are a lock and Monday morning could be 0 to 5.

Not exactly...Just to clarify the terminology a bit...when meteorologists talk about a ‘dry slot,’ they’re referring to the dry conveyor belt wrapping into a mature cyclone. It’s a broad synoptic feature that shows up in global mass fields and satellite water‑vapor imagery. It’s not something the NAM typically resolves well at the end of its run, and the model actually has close to an inch of QPF down by midnight Fri/Sat, which suggests a fully intact precip shield rather than a dry slot intrusion. About the analogs I posted earlier: When I mentioned Feb 2003 and Dec 2013, I was referring to the H5 pattern and overall pattern structure, not the exact surface impacts. Those events share several large‑scale similarities with this setup: 1) A deep, well‑established Arctic air mass 2) A southern‑stream disturbance ejecting from the Southwest 3)Strong overrunning and isentropic lift 4) A marginal warm layer aloft that cools with time 5) A broad, long‑duration precipitation shield Dec 2013 did produce some icing, but the event was actually sleet‑dominant because the warm nose was shallow and weak. That’s why it’s a useful analog here — the thermodynamic structure favored sleet, and this system is showing a similar profile so far. So the comparison isn’t about matching the exact precipitation type outcome — it’s about the larger‑scale pattern and storm mechanics. From that perspective, the analogs line up pretty well.

FWD has also place its entire FA under a Winter Storm Watch. The chance of temperatures getting to 5 or colder with this event, even in the heart of the Metroplex has increased markedly. The majority of all ensemble members show temps now in the single digits as do the operational models. NBM now is down to 10°F. I fully expect Extreme Cold Warnings to go up with this.