Roger Smith

The idea of "too cold for lake effect" is a bit of an urban legend, the lakes warm the frigid air to the extent that it can hold enough moisture to remain very capable of maxing out. Without Lake Erie there BUF would probably drop to 12F but the lake will release enough heat into the squall band to maintain a reading of 18-22F (at a guess).

Some estimates of timing for the front ... in EST NYC _ 1130 central LI w CT 1200 central CT and Springfield MA 1300 ORH-PVD 1340 BOS 1420 Cape Cod 1530 Expect about a one-hour lag for sharp temp drops after the fropa I would expect it to be a discontinuous squall line with isolated gusts to 70 mph possible but 50-55 more general, lasting about a half hour, then 35-45 during the CAA.

Arctic front is about one hour behind that sleety line, temp drops of 20-30 deg in 2 hrs have been reported all through the OV and w PA. It is near -10 F with 35 mph wind gusts in most of western OH, IN and IL. 2-4" snow quite widespread in Ohio and parts of wPA so you may get a coating in some parts of nMD despite the downslope dry out. My guess is the temp at DCA at noon will be 24F, IAD 20F and parts of nMD 15 F. Wind chills below zero.

Looking at radar in WV, front seems to be fairly active, would expect some hail and thunder followed by a few minutes of snow in some parts of the lowlands, a coating of snow across nMD before the strong winds set in, blowing that around. Bright sunshine to follow will not help make driving any easier, and icy patches on some roads quite likely as there could be .10" rain or sleet falls ahead of the fast temp drop. Temps down to 5-10 F by Saturday morning.

Maybe it was 998.2 mb, weather maps include the decimal so a weather station reading 982 is at 998.2 mb.

Give it three hours and it will be almost something instead of basically nothing.

No earthquake warning? With all this air and water moving around, the crust will be under stress, would expect a minor earthquake in NY or PA tomorrow or Saturday. Also new moon on 23rd, so a bit of additional tidal force.

Blending all models with a nowcast on that Alpena forecast, right now it appears to me that some of the guidance is too progressive. The surface low is holding back a bit further west than the hour to hour positions on 18z models and so their 0600z positions appear too far east by at least 50 miles. I think the low will track very close to APN although it will elongate to form a double center with the eastern circulation. So my forecast was based on more of a nowcast approach than any direct model to forecast approach. Lake Huron as you know is quite warm compared to the air mass temperature coming in but so is Lake Michigan and I wonder if the models entirely processed those signatures into the first part of the evolution. All of the upper level circulations are well back to the west of Lake Michigan so a deepening low should in theory try to move towards the upper lows which may pull it back a bit further west at least through 06z. The explosive deepening phase is just starting now. It should continue for the next 12 hours or so.

During the explosive deepening phase I would expect rain to change to ice pellets and then heavy wet snow with thunder quite possible. From my reading of current map and guidance, the rapidly deepening low will head up through central s MI towards your location by 0600z and then may hover in place for a while as it connects through to the eastern center moving north across L Ontario. Eventually it drifts far enough north that you get into much colder air from the west, snow will remain heavy for a while then come and go in bursts as it becomes more lake effect and less synoptic. I think the deepening phase will drive out the 32-35F dew point air over Lake Huron and allow the rain to change phase, but it could go through a couple of oscillations along the way with heavy ice pellets quite possible around 02-04z. Let us know as you're sort of at ground zero for this.

00z NAM looks to be an upgrade especially for s MI. The low stays on the Michigan side of L Huron through the deepening process. I don't know if it does any good for Chicago, but it may mean that some forecast amounts for MI are low. I think this evolution is going to create sustained S+ bands across much of lower MI and amounts of 20-25 inches could occur in a few places. Will go for 22.5" at GRR, 15.0" LAN, 6.0" DTW, 12.5" MBS and 17.5" APN, possibly 18-25" TVC and MKG over the full duration of the storm.

Posted back on Monday, adding the ranks 13-18 (all the 35 deg drops) ... For potential comparison to 23rd-24th change in NYC max temp, these are the top twelve downward differentials from day to day, 1869 to 2022: _ Rank ___ Dates _______________ From _ To ___ diff _ 01 _____1918 Feb 20-21 ________59 __ 18 ____-41 _ 02 ____ 1921 Mar 28-29 _______82 __ 42 ___ -40 _ 03 ____ 1927 Dec 8 - 9 ________65 __ 26 ___ -39 _ 04 ____ 1915 Apr 26-27 _______ 92 __ 54 ___ -38 _t05 ____ 1896 Feb 16-17 _______ 44 ___ 7 ___ -37 _t05 ____ 1978 Jan 9-10 ________ 58 __ 21 ___ -37 _t05 ____ 2003 Apr 16-17 _______ 88 __ 51 ___ -37 _t08 ____ 1876 Jan 10-11 ________60 __ 24 ___ -36 _t08 ____ 1911 Nov 12-13 ________69 __ 33 ___ -36 _t08 ____ 1933 Feb 8 - 9 ________ 60 __ 24 ___ -36 _t08 ____ 1970 Feb 3 - 4 _________56 __ 20 ___ -36 _t08 ____ 2014 Jan 6 - 7 ________ 55 __ 19 ____ -36 _t13 ____ 1890 Feb 5 - 6 ________ 68 __ 33 ____ -35 _t13 ___1898 Dec 31-1899 Jan 1_ 53 __ 18 ____ -35 _t13 ____ 1918 Jan 12-13 _________53 __ 18 ____ -35 _t13 ____ 1934 Mar 18-19 ________71 __ 36 ____ -35 _t13 ____ 1939 Apr 25-26 _______ 86 __ 51 ____ -35 _t13 ____ 1959 Mar 21-22 _______ 69 __ 34 ____ -35 _t19 ____ _t19 ____

I saw that attempt at a loop GFS, just like the Euro once had. I think what that loop means is the model recognized the main shot of energy and allowed it to take over from junior out ahead. Maybe it will happen that way or maybe there will be more of an organized low coming out of Texas. Might be almost nowcasting the details. Models are still losing the western center after it drops into TX. Isn't there a general tendency for models to underestimate snow potential in the Mississippi valley region? Seems that way over the past few seasons. There was that recent winter with the record snowfalls in Moline, La Crosse and MSP and it seemed like half that snow was not in the forecasts. Was that winter 20-21? (no it was 2018-19 time flies)

00z RGEM to 48h looks like a storm recovery trend may be slowly underway? An interesting night of model watching lies ahead.

Apologies if my comment seemed related to that, I was just commenting on a graphic in somebody's post showing the low tracking further east in Ontario than what I recall. That was possibly the track of the triple point though. In Toronto we went from 40F and rain at 0700h to 18F and snow two hours later. The fropa had wind gusts over 70 mph locally whether that was picked up at airport or not, in fact where I normally parked there was a big a/c unit that had blown off the roof five minutes before I arrived for work. So that plus the fact it was still mild at 0700h tipped me off that the prog position had busted.

That's all quite interesting about 1-26-78 but the actual storm track was closer to Sarnia-Port Huron and up Lake Huron, I was actually in a weather office drawing up a map at 0800h and still have the map. There was a pressure of 955 mb at Sarnia and at one point maybe around 09-10h London ON had hurricane force southerly winds that were wrap-around arctic air. This won't quite get that wrapped up anywhere. I realize the technology has improved but the 24h prog position of that storm was over western Lake Ontario (it came up from around central AL). We were expecting a snowstorm in Toronto and got one from the wrap-around instead of northeast winds, so the public were not that aware of a forecast bust. I think it probably came as more of a shock further west, the intensity was quite unforeseen in southwestern ON. Those winds knocked down several large hydro-electric towers in that region. You don't often see arctic air blowing from the south in that part of the world.

This thing is over me here and we are seeing three times the model predicted snowfall (easily a foot and maybe more, we had a forecast of 3-6 inches). Some model runs have had a sub-960 mb low over central ON and the trajectory looks perfect for another mega-squall event around BUF and wNY. On current guidance I would think 60-90 inches quite possible 24th-26th with extreme winds (although squall bands tend to do odd things with winds inside the heavy snow zones). Similar to mid-November, your seasonals are going to go through the roof. Is Buffalo scheduled to be playing at home during any of this? There were events something similar to this in Nov 1970 and Jan 1971, that was quite a snow belt winter.

Just hope Belicheck doesn't send in the play. Mind you, you want this thing to run back towards its own end zone.

Both NAM and GFS look a bit off in their handling of the short wave rounding the base of the trof, they seem to be trying to develop the eventual low out of the leading wave and trof in place ahead of the energy and they suppress the short wave as a sort of last piece of energy for the southeast U.S. cold front. I think earlier model runs may have had a better depiction with the energy rounding the base of the trof deepening over MO and IL rather than this concept of the low forming in IN and moving to MI. Either way all of the expectations for MI, sw ON, wNY snow belts would verify but there may be a better (worse for public) outcome for WI and IL, maybe even IA and MO. Later model runs (perhaps starting with 12z Euro) may start to drift back to the earlier more intense solutions. I can't see how the overperforming start here would translate into a weaker short wave rounding the base after DEN gets a brief blizzard tonight and Wed a.m., would expect a snowstorm to develop in OK and s KS as the low drops into Texas. I think it will stay more of a dominant feature rather than getting absorbed into some developing low way out ahead of the main energy.

FWIW the low moving on shore now has overperformed in terms of snowfall across southern BC, Vancouver region has 8-12 inches after a forecast of 3-6, and here inland (north of Spokane at the border) we also have 6-8 with same forecast. The low is just south of Bellingham WA with a leading wave near Spokane.

06z NAM has the center steadily deepening to 970 mb tracking up western L Huron to near APN MI by end of run 18z Friday and would give sw MI possible 2-3 feet of lake effect snow with 60 mph wind gusts. From that track I think ORD would see 5-8" and that would increase around southern L Mich to 24 inches by Benton Harbor, probably about 18" for SBN mostly lake effect. Storm pulls in Atlantic moisture but probably too late if this model verified, heavy snow for ne ON. Lake Erie squall potential looks high after fropa and could give BUF another heavy fall late 23rd into 24th. Could all change on later guidance of course, but there seems to be no plausible track that would fail to dump very heavy snow in sw MI and n IN. Given the likely temps and wind speeds, long-lead warnings were certainly justified and even 1-3 inches of snow blowing around in those conditions would be very dangerous.

For potential comparison to 23rd-24th change in NYC max temp, these are the top twelve downward differentials from day to day, 1869 to 2022: _ Rank ___ Dates ___________ From _ To ___ diff _ 01 _____1918 Feb 20-21 ____59 __ 18 ____-41 _ 02 ____ 1921 Mar 28-29 ___82 __ 42 ___ -40 _ 03 ____ 1927 Dec 8 - 9 ____65 __ 26 ___ -39 _ 04 ____ 1915 Apr 26-27 ___ 92 __ 54 ___ -38 _t05 ____ 1896 Feb 16-17 ___ 44 ___ 7 ___ -37 _t05 ____ 1978 Jan 9-10 ____ 58 __ 21 ___ -37 _t05 ____ 2003 Apr 16-17 ___ 88 __ 51 ___ -37 _t08 ____ 1876 Jan 10-11 ____60 __ 24 ___ -36 _t08 ____ 1911 Nov 12-13 ____69 __ 33 ___ -36 _t08 ____ 1933 Feb 8 - 9 ____ 60 __ 24 ___ -36 _t08 ____ 1970 Feb 3 - 4 _____56 __ 20 ___ -36 _t08 ____ 2014 Jan 6 - 7 ____ 55 __ 19 ____-36

This alleged warmup after the holiday cold snap looks like a 10-15 day event with zonal flow from Pacific across the continent, it will be mild (40s to low 50s) but maybe not record mild. Tends to be a dry pattern also with weak frontal systems. Similar events in Jan 1948 and 1961 dominated first halves of months that turned bitterly cold later, with coastal storm opportunities. Or perhaps this goes a bit more like Jan 1982 which had a mild opening week before deep cold and coastal storms developed after about the 8th. So it may not be such a bad thing to see this pattern change across the west, could reset a good pattern in the climatological peak of winter. We have been consistently 4-8 F below normal around here since about 20th of October, and it is particularly cold today (current mid-afternoon reading 5F or -15C with 45 cm snow cover). CFS coastal? Not gonna happen, at least not with that intensity. The big story will be that very sharp temperature drop on the 23rd. My guess, 57F noon, 32F 6 p.m., 18F midnight. Will run a program on NYC data base to find largest day to day differentials in max temp, 23rd-24th may give whatever record exists there a run. Maybe that Nov 1911 event would win top prize.

At this stage it's probably more like the average positional error, I think the pattern emerging will sustain a 960-970 low somewhere within 200 miles of Detroit in any direction. There is probably about a 10% chance of this continuing to push further north on later model runs to the extent that MSP and DLH get the sweet spot, and there's maybe a 10% chance of it returning to a coastal, a 20% chance it's more like an Apps runner, and various other percentages closer in to the consensus track today. With the heights crashing on all guidance and -40 C air mass emerging out of northwest Canada already today, can't see how this fails to deepen explosively once it rounds the base of the trough. I think there could be minor shifts back towards the Ohio valley to Cleveland sort of a track as the cold air pushes in ahead of the final wave and forces it to take a sharper curve around TX-AR. As intense as this looks now, there are ways it can actually become more intense. It really doesn't pull in a lot of Gulf moisture for example but a sharper trough might do that.

Not sure about the loop near southern L Michigan on the ECM, but anyway, all models now coming into a fairly good agreement that this is essentially a windstorm with severe lake effect squall potential and moderate synoptic scale due to lack of moisture and short duration of over-running at any given location. It's a bit different in evolution from 1-26-1978 in that it deepens over the Midwest rather than bombing out from a southern origin (AL to Lake Huron for Jan 78). Looks like a top ten wind event and depends where you are relative to squall bands for snow or actual blizzard, but ground blizzard would be widespread given some snow and the fierce wind gusts. The chill would also be lethal. The timing could hardly be worse, start of a weekend Christmas travel period. That's going to turn into a four-day stay at some stranger's farm house in some cases. Pack gear.

I'm reading this as a slow transition event that eventually changes over to snow just about everywhere, without the huge gradients and snow in the 4-8 inch range for most, after some rain and sleet for some. It looks like a coastal snowfall event near the end of the precip but that could be melting on contact snow south of BOS. But I only have success with the likes of Nemo and Blizzard of 1888.