aggiegeog

Pretty impressive reports out of DFW and West this morning.

DFW starting to see some sleet. With the lower wet bulbs east of Dallas towards Tyler things may be more sleet/snow mix before rain mixes in closer to noon.

As expected temps have risen to at or above freezing in man y areas though with DPs in the low 20s we have plenty of room for wet bulbing back to freezing. The warm nose aloft for DFW should wet bulb to freezing +/- 1C also for I20 in N and E TX a bit warmer as you get towards LA. Difference is DFW loses its warm nose during the evening and E TX warm nose lowers and becomes stronger during the evening. For E XT the transition to all snow will be after midnight.

I'll take my chances with GFS. It keeps me at 32F through the whole event. Precip types just vary as warm nose builds then erodes.

No models besides the crazy Canadian are close to cold enough at initialization. Canadian is way too cold. Bizarre that all hi res models are initializing 4+ degrees warm right now. Most models have freeze line along I20 when it is actually south of Lufkin. 26 here in Lindale along I20 now. Some stations as low as 23 around East Texas.

It can but that is but 3C is only on the warmest models. Some have the more like 1C or even 0C.

27 in Lindale out north of Tyler, that is our forecasted low. DP of 22 so still some room to drop before clouds arrive.

We will soon see but nice to start a storm with cold ground. If we can get a solid layer of sleet to accumulate in the morning then that can insulate later precip from ground warmth even as surface temps may warm during the day. Also heavier precip can pull cold down and eliminate the slight warm nose.

Warm nose is expected to be very minor like max 3C around I20 and maybe only 1C depending on model. And those warm layers are shallow, generally less than 150mb. A decent amount of sleet for a long I20 but closer to I30 should be basically all snow. Some models show even I20 to be mainly snow profile.

Freeze line has sagged south of I20 already across Texas. 31 here in Lindale which is round 3 degrees lower than expected at this time. Not sure how much effect that has in the end but def can't hurt to have 12+ hours below freezing before onset even if onset warms things some. Models continue to ramp things up across N and NE TX. Most schools have already closed around here.

That does look really solid. 3-6" snow for DFW, 4-8" snow for I-30, 1-3" sleet/snow for I-20.

SHV expanded warning to include all of the former watch and added an advisory for counties south of I20. I see Advisories are now issued down to Del Rio for all of the Hill Country west of I-35.

FTW filling in their region with WWA now. I expect West Texas and SHV will fill in their regions shortly with WWAs.

Most Hi-Res models as well as RGEM indicating colder temps tomorrow. gonna be a close call on if just a rain/sleet mix tomorrow or all frozen with travel issues.

Around here key is the warm nose tomorrow 1C or 4C. Surface will be 32-35F so at 1C sleet is likely but at a warmer warm nose it could just be cold rain with some sleet. By sometime tomorrow night it should transition to snow or rain/snow2010 is still on the table with this event.

Again this morning for the Tyler area, there is a massive range of outcomes from mostly rain with some mix to a foot of snow. As expected hires models show a colder profile. Again models print out 1-2" QPF area wide. I still do not see much freezing rain with this though there will be some. Areas where sleet is the main type are looking at 1-4" accumulations (say maybe areas from Hillsboro to Carthage up to maybe Tyler/Longview). A more even mix of sleet and snow would be like 4-8" (maybe Cleburne to Longview type areas). The main snow band will be a general 6-10" with some over a foot (thinking I-30 is a good bet).

Assuming we do get the 1 to 2" QPF and temps are at least partially supportive of frozen precip then amounts will be significant. Heck 0.5" QPF of sleet gets you to over an inch and I think that is certain at least east of I-35.

There is a reason I have held off on updating my official forecast for the event. They do not have that option. They very well may be revising right back up tonight.

Man I feel for them having to attempt to forecast this. SHV also lessening their amounts it seems.

Man, the data this afternoon is highlighting some extreme snow possibilities for NE TX. This is a wildly volatile setup.

Most of the model sites only plot snow or freezing rain. Have to interpret sleet in between. I believe so will see hefty sleet totals out of this. 1" QPF with a profile fluctuating near 0C could result in multi inch sleet.

agreed that it is wild that we are having this much model trouble within 48h of onset. RGEM has 2" QPF for DFW and NAM has basically 0" QPF. Other models in between but none go anywhere close to 0 for DFW. 06Z NAM fell in line with other models then 12Z just goes way off by itself. Super odd behavior even for the sometimes crazy NAM.

Yea its interesting for sure. SHV is even more conservative than FTW with these typically and they actually issued their watch before FTW. It seems that they are leaning on Euro heavily, I agree with that myself. I think the NAM is just being its wonky self, we are still in extended range for the NAM we have to remember. It is pretty clear that for DFW east we are looing at around 1" QPF with sub 35 temps. The question is mainly on when the SW trough and northern stream shortwave phase, I lean on Euro solution of this happening early. The earlier they phase the faster we get precip and the less the mid level WAA ahead of the storm. Also watching to see how much the Rockies high can press into the backside of this storm with cold air without shutting down precip.

Models this morning really want to hang a chunk of the trough back in the SW which is killing our event. I still think this has a good chance to revert back to previous solutions assuming we can get the trough to eject whole.

NWS has hoisted watches for N and NE TX. Solid snow for N and NE TX. Major ice and sleet with some snow for E TX.