StormChazer

Not that the Canadian is an outstanding model, but it also trended colder and snowier.

So while the GFS did trend slightly colder, it drops much less precip. Interesting.

GFS looks to be coming in a little colder so far.

I suspected as much. Good to know, thanks!

Btw, I never got a chance to welcome you to the boards! I've dabbled in posts here and there in the past, but this is my first real year of posting alot. Any new faces are welcomed!

It's funny because that doesn't seem like much, but at the same time, that is drastic. Question, do you know if the models in any way play off each other? Like, if the NAM is coming in cold, is there anything in the GFS or Euro's algorithms that take that into account? I would think probably not, as they're entirely separate entities, but it bears asking the question.

Wow!

So it begins.... here is the NAM at 6PM Friday Here is the GFS at 6PM Friday

I went ahead and tallied up the ensembles(not counting control or master) of last night's Euro run. 19 members have Tulsa missing out or getting under 1-2 inches. 12 members put Tulsa RIGHT on that steep gradient(we're talking north Tulsa county gets 8 inches, south Tulsa county gets 1-2 inches), or is within a county away from the high totals. 19 members have Tulsa getting a good dumping of snow. This is the 3rd time I've done this and pretty much we are back to my first analysis where the number was 17 12 21 But no doubt we lost some ensembles in the heavy column to the "right on the line" column. So the way I see it 38% say heavy snow 38% say little to no snow 24% say within 20 miles you go from no snow to 8 inches. I may be biased because I want this snow, but I feel this category has to lean in the heavy snow category's favor, seeing how cold air tends to spread a little more than models think. I'll do another one of these for the 12Z run today.

I've lived in North TX for about 25 years and OK now for 3, and when it comes to winter weather events, they tend to play out nearly identical. I know in my experience, it seems more often that not, that 24 hours or so before the event, everything tends to trend just a little cooler. Probably because the models need to initialize colder and start to pick up on how to handle the cold air just a bit better(which tends to be that it's underestimated the cold air), this usually sees winter storm watches or other advisories bump up an extra line of counties. Once this storm comes on shore, I think we'll get a much better painted picture, and today's NAM runs will be particularly useful since it handles cold air better(the two runs so far have already shown the air is colder than any other models). I'll say this much, every time I can recall that I've ever received a heavy dumping of snow, it's been when the forecast calls for maybe half that, and then the cold air comes in quicker and doubles our totals out of "seemingly" nowhere. I'd love to see the GFS and Euro start a cooling trend today, but frankly, the long range models are always going to struggle with this cold air, it's just the nature of the beast. My eyes are going to start focusing on the NAM here soon.

Do these two usually correlate to each other?

Max range on the NAM, so take it for what it's worth, but this certainly is a much colder solution than every other model.

I’ll agree the snow line confuses me.

No need to throw in the towel. It’s 1 run. This far out, so much is still subject to change. The Euro ensembles showed that the Euro master didn’t line up too well, it could very well dip back down tonight for all we know. I’d wait until Wednesday before getting too upset!

For those wondering, here is the current snow pack. It's going to stay cold up in Nebraska, so should be interesting to see if this has any affect in speeding up the cold air.

Tulsa thoughts on the upcoming system. "The strong system in the southern stream over the E Pac is forecast to move across the southern tier of states, and will tap a plentiful moisture source from the Gulf to produce widespread precipitation over the south central states. Coincidentally, a strong shortwave trough in the northern stream will force a cold front thru the region Thursday with colder air filtering into the region thru the weekend as surface high pressure settles south into the central Plains. This one-two punch on the separate streams of the westerlies tends to bring some of the bigger winter weather events for our part of the world. Using a blend of the thermal profiles aloft and the raw surface temps (which have trended warmer slightly) from the GFS/ECMWF, and using the latest QPF (the character of which is very similar between the GFS/ECMWF), this forecast will continue to suggest the potential for a winter storm across portions of NE OK and NW AR. Snow and sleet are expected to be the primary winter weather types, with some very light icing possible at precip onset down along the I-40 corridor. Rain will be predominant thru much of the event south of I-40, with a change over expected toward the end of the event Sat/Sat night and thus lighter accums. The details will continue to be refined in the coming days, especially as we get into the time frame of the NAM and its better handling of cold air in a day or so. Stay tuned for updates. Travel impacts across portions of the region are looking more likely."

GFS is up and running. Will post thoughts shortly!

My vote would go to #49; would make up these past few snowless years. If only! Haha

So the following is the 12Z members and what I found for the immediate Tulsa area... 16 members have Tulsa either missing out or under 1-2 inches. 8 members put Tulsa a hair away or right on the line on heavy totals. 26 members dump a heavy swath of snow across Tulsa and surrounding areas. So comparing the two, the biggest difference is that 5 members shifted from the middle and low column to the high column in Tulsa's favor. So I won't really complain too much about this. Lost ground on the master, but gained ground in the ensembles.

Now that I look at it, I think that may still be the 0Z, let me double check. If not, once it's updated I'll do the same thing to compare and contrast.

Well, I analyzed the 50 members for snowfall and at least for Tulsa, this is what I came up with. 17 members have Tulsa either entirely missing out on snow, or getting less than 1-2 inches. 12 members put Tulsa a hair away from the heavy totals, we're talking going from 1 to 10 inches in a span of one county. 21 members dump a heavy swath of snow across Tulsa(and most of NE OK), "heavy" being 5+ inches. Still just so much more time to go before zeroing in on the totals, but this run of the Euro has definitely made things much more cloudy. Midnight can come fast enough, haha.

Not sure how to interpret that one. I know we aren't supposed to focus on single model runs, but rather trends. But coldest to warmest has me wondering if this will end up as a run that went out to lunch, or if it's picking up on something. You would think if it was picking up on a warmer solution though that the GFS would have been even warmer.....looking forward to getting some shorter, higher res models into the fray soon. Also very curious now what tonight's Euro shows. I will say looking through the various members for snowfall, there is a very large number of models with high totals.

Here is every run of the Euro since the noon run on Thursday. I've adjusted the timing only slightly to try and visualize it better to get the frames matched up. This is more or less, Midnight Friday, so the frames following show a snowy scenario continuing into Saturday, but I thought this a pivotal point in the forecast to display. This is some fantastic run to run consistency, the only run that deviates anything meaningful is the 0Z Saturday run which depicts an icier solution with the colder air more north, before transitioning to snow. The other thing to notice is the precip shield moving more to the south and leaving KS and MO with less and less, although this hour in the storm doesn't highlight that aspect very well, I'd need to jump ahead 6 more hours for that. On the other side of things, the GFS has had some flip flopping issues. It'll go 2-3 runs agreeing with the Euro and then BOOM go another 2-3 runs keeping the cold air way north into Kansas, then cave again to the Euro, rinse and repeat. It's done that about 3 times now, and we'll see if the 12z run today brings it more in line with the Euro after seeing it inch southward on the 6Z. Point is, the Euro has been very consistent and handles these things quite well, so that's where I'm putting my faith for now.

I know I sound like a broken record, but as of the 06Z GFS, it started trending south again, I suspect if it continues the pattern it's been on, the 12Z will have an even further south solution, and eventually it'll stop trying to keep the colder air north, this is all assuming the Euro is to be believed. Quite honestly, the Euro's run to run consistency since Thursday of last week has been quite impressive, the only changes in it's runs overall have been to bring the precipitation shield further south, causing MO and KS to miss out on the snow, but in terms of where the freezing line sets up, it has been very consistent. Today's runs are very important, we are only 4 days out now from the onset of the freezing precip depicted. If the Euro maintains, and the GFS creeps a little more south, I'd say that should lead to some moderate to high confidence in this storm, and by tomorrow night snow amounts can start to be discussed.

The GFS is known for not handing cold air very well, the Euro tends to have a better grasp. I think the snowpack could indeed have some impact on how far south it travels. If the Euro holds on like it has the last few days, then I’m going to trust it over the flip flopping gfs.