Re: February 27th-28th 2023 Winter Storm

by **billg315** Mon Feb 27, 2023 12:17 pm

MattyICE wrote:Some things I like to remind myself of as we get closer:

1) latent heat release. This storm is producing quite a bit of convection out in Illinois. This can pump things out ahead a little bit. We look for this factor when storms are modeled to far out to sea to try to nudge the system more N and W. No idea if this will come into play but could be a wildcard for fringe spots.

2) speed and duration. This likely comes in ahead of schedule and lasts more quickly than we think it might and ends quicker. Think of how many times one model or another made it look like it would precipitate hours longer than it ended up. I think any appreciable accumulating snows are done by daybreak.

3) what falls from the sky may not be what accumulates. 6 inches could fall. But how much melts initially. How much gets compacted with snow that is more wet than powdery and does qpf get wasted on sleet? All of that can result in 2.5 inches of slush and yet a 3-6 call would have still been accurate

There’s probably more but regardless many their first real snow tonight! I do think from 80ish on north is going to end up doing quite well.

#2 is a persistent pet peeve of mine. Models love to indicate long, drawn out events that in reality end much more abruptly once the storms begin to accelerate northeast.

by WinterColdandSnowisamyth Mon Feb 27, 2023 12:23 pm

amugs wrote:GFS 12Z says hi

Not a fan of the GFSin the short term, or even the long term the last couple of years.

As shown there NYC straddles the change line and seems to snow heavy snow, at least from Central Park north, almost throughout. That could surprise many total wise if it happened as depicted. I would tend to think it won’t happen quite as intensely as depicted there.

by **sroc4** Mon Feb 27, 2023 12:25 pm

billg315 wrote:
MattyICE wrote:Some things I like to remind myself of as we get closer:

1) latent heat release. This storm is producing quite a bit of convection out in Illinois. This can pump things out ahead a little bit. We look for this factor when storms are modeled to far out to sea to try to nudge the system more N and W. No idea if this will come into play but could be a wildcard for fringe spots.

2) speed and duration. This likely comes in ahead of schedule and lasts more quickly than we think it might and ends quicker. Think of how many times one model or another made it look like it would precipitate hours longer than it ended up. I think any appreciable accumulating snows are done by daybreak.

3) what falls from the sky may not be what accumulates. 6 inches could fall. But how much melts initially. How much gets compacted with snow that is more wet than powdery and does qpf get wasted on sleet? All of that can result in 2.5 inches of slush and yet a 3-6 call would have still been accurate

There’s probably more but regardless many their first real snow tonight! I do think from 80ish on north is going to end up doing quite well.

#2 is a persistent pet peeve of mine. Models love to indicate long, drawn out events that in reality end much more abruptly once the storms begin to accelerate northeast.

Except this storms trajectory is ESE; not NE. Same difference though. It almost always begins at or earlier than modeled and def finishes earlier

by WinterColdandSnowisamyth Mon Feb 27, 2023 12:27 pm

MattyICE wrote:Some things I like to remind myself of as we get closer:

1) latent heat release. This storm is producing quite a bit of convection out in Illinois. This can pump things out ahead a little bit. We look for this factor when storms are modeled to far out to sea to try to nudge the system more N and W. No idea if this will come into play but could be a wildcard for fringe spots.

2) speed and duration. This likely comes in ahead of schedule and lasts more quickly than we think it might and ends quicker. Think of how many times one model or another made it look like it would precipitate hours longer than it ended up. I think any appreciable accumulating snows are done by daybreak.

3) what falls from the sky may not be what accumulates. 6 inches could fall. But how much melts initially. How much gets compacted with snow that is more wet than powdery and does qpf get wasted on sleet? All of that can result in 2.5 inches of slush and yet a 3-6 call would have still been accurate

There’s probably more but regardless many their first real snow tonight! I do think from 80ish on north is going to end up doing quite well.

I had written something very similar earlier today, along the lines of in the northern areas where 8 to 10 inches is predicted they are much more likely to end up with that on the ground. The border line areas where 3 to 5 inches are predicted may I actually see 4 inches at the beginning of the storm and end up with nothing or an inch of slush on the ground when it ends. Technically the Maps are correct but the sledders are left with nothing to show for it.

by **phil155** Mon Feb 27, 2023 12:32 pm

at 46 degrees here in edison, seems a bit too warm

by **heehaw453** Mon Feb 27, 2023 12:55 pm

phil155 wrote:at 46 degrees here in edison, seems a bit too warm

I have to agree. I'm at 43.5. I think it will affect accumulations. I'm seeing 40's right into NW NJ and LHV currently. Wet bulb will occur, but the fact of the matter is the antecedent ground is warm.

by **sroc4** Mon Feb 27, 2023 12:55 pm

Im still at 36*. Hasn't budged

by **heehaw453** Mon Feb 27, 2023 1:13 pm

We can slice and dice this anyway we wish. The surface is warm for most folks. I'm not saying it won't snow just the accumulations may be affected.

First pic is current temps and second are current wet bulb temps. Sroc land is probably getting winds off LI Sound to keep it cooler.

February 27th-28th 2023 Winter Storm - Page 3 Temps26

February 27th-28th 2023 Winter Storm - Page 3 Wetbul29

by **jmanley32** Mon Feb 27, 2023 1:18 pm

Yeah way to warm here, gonna be hard to stick.

by **heehaw453** Mon Feb 27, 2023 1:23 pm

jmanley32 wrote:Yeah way to warm here, gonna be hard to stick.

I'm at 43.5 Lol.

by **Frank_Wx** Mon Feb 27, 2023 1:28 pm

I removed the censorship that was placed on the word Kuchera. I read that modifications and improvements have been made with the logic, and this storm may be a good test to see how it performs considering surface temps are above freezing for many along the coast. If it fails me again, I am putting the censorship back on!

Here is the 12z EURO Kuchera snowfall map

February 27th-28th 2023 Winter Storm - Page 3 Snku-acc-imp-us-state-ne-s

February 27th-28th 2023 Winter Storm - Page 3 Snku-acc-imp-us-state-ne-s

by **Dunnzoo** Mon Feb 27, 2023 1:28 pm

42.6* here now, going to rely on the table and not the ground for measuring unless the temps drop quickly this afternoon. If the precip holds off til 8 pm or so, it might just cool down enough to stick from the get go. I'm sticking with a 4-5" event for me and mugs, but wouldn't be surprised if we get to 6".

by **phil155** Mon Feb 27, 2023 1:31 pm

snowfall rates will have to be impressive to overcome the warmth if this is to work out at all. I am in Edison and really not expecting much at all

by **sroc4** Mon Feb 27, 2023 1:36 pm

Dont panick too much yet folks. Here is the surface temps valid as of 2pm and then again by 7pm. Temps will drop again. Its all part of the plan. The details as to why I have been referring to the Kuchera maps is because the coastal plain will not likely see great ratios due to these marginal temps. You just cant look at the 10:1 maps. The latest Kuchera upgrades have def done much better this season. Again I know we all want 6+ but its not likely to be the norm along the coastal plain. IMHO. There will be however areas to over perform as well as underperform....happens every storm

February 27th-28th 2023 Winter Storm - Page 3 1677524400-brnhHjRP10I

February 27th-28th 2023 Winter Storm - Page 3 1677524400-brnhHjRP10I

February 27th-28th 2023 Winter Storm - Page 3 1677542400-BOpqdXoI0No

by CNWestMilford Mon Feb 27, 2023 1:38 pm

Frank_Wx wrote:I removed the censorship that was placed on the word Kuchera. I read that modifications and improvements have been made with the logic, and this storm may be a good test to see how it performs considering surface temps are above freezing for many along the coast. If it fails me again, I am putting the censorship back on!

Here is the 12z EURO Kuchera snowfall map

Once again another increase and more widespread accumulations from 0z.

by **heehaw453** Mon Feb 27, 2023 1:43 pm

I'm watching this ULL. If it doesn't open up in the next hour or two it will have big impacts on the bad side for us.

February 27th-28th 2023 Winter Storm - Page 3 Ull18

by **jmanley32** Mon Feb 27, 2023 1:45 pm

CNWestMilford wrote:
Frank_Wx wrote:I removed the censorship that was placed on the word Kuchera. I read that modifications and improvements have been made with the logic, and this storm may be a good test to see how it performs considering surface temps are above freezing for many along the coast. If it fails me again, I am putting the censorship back on!

Here is the 12z EURO Kuchera snowfall map

Once again another increase and more widespread accumulations from 0z.

However a drastic decrease IMBY according to that map, so i am going with 1-10 inches depending on which model you look at lol, and the fact if it changes to rain I may see nothing in the morning. And ouch the sledding comment, that's my girl give her a break she deserves it after 2 years without.

by **heehaw453** Mon Feb 27, 2023 1:47 pm

sroc4 wrote:Dont panick too much yet folks. Here is the surface temps valid as of 2pm and then again by 7pm. Temps will drop again. Its all part of the plan. The details as to why I have been referring to the Kuchera maps is because the coastal plain will not likely see great ratios due to these marginal temps. You just cant look at the 10:1 maps. The latest Kuchera upgrades have def done much better this season. Again I know we all want 6+ but its not likely to be the norm along the coastal plain. IMHO. There will be however areas to over perform as well as underperform....happens every storm

Sroc this is about accumulations really. It will snow I have no doubt, but what I think is push comes to shove the snow depth algorithm is best for this event, not kuchera or 10:1. This is what I believe reality holds for this event.

February 27th-28th 2023 Winter Storm - Page 3 Snowde14

by Coachgriff Mon Feb 27, 2023 1:49 pm

The timing of the snow will be very interesting as it appears that much of the front end thump will be occurring when temps are well above freezing…by the time things cool for sticking to occur those who live south of 80 will be seeing a changeover. I am pulling for the members N/W…I think most of NJ isn’t going to make the cut.

by WinterColdandSnowisamyth Mon Feb 27, 2023 1:52 pm

Frank_Wx wrote:I removed the censorship that was placed on the word Kuchera. I read that modifications and improvements have been made with the logic, and this storm may be a good test to see how it performs considering surface temps are above freezing for many along the coast. If it fails me again, I am putting the censorship back on!

Here is the 12z EURO Kuchera snowfall map

Probably the most realistic map I’ve seen today.

by CNWestMilford Mon Feb 27, 2023 1:58 pm

jmanley32 wrote:
CNWestMilford wrote:
Frank_Wx wrote:I removed the censorship that was placed on the word Kuchera. I read that modifications and improvements have been made with the logic, and this storm may be a good test to see how it performs considering surface temps are above freezing for many along the coast. If it fails me again, I am putting the censorship back on!

Here is the 12z EURO Kuchera snowfall map

Once again another increase and more widespread accumulations from 0z.
However a drastic decrease IMBY according to that map, so i am going with 1-10 inches depending on which model you look at lol, and the fact if it changes to rain I may see nothing in the morning. And ouch the sledding comment, that's my girl give her a break she deserves it after 2 years without.

12z above …0z below.

February 27th-28th 2023 Winter Storm - Page 3 5cb9f910

February 27th-28th 2023 Winter Storm - Page 3 E1ad5010

by **Frank_Wx** Mon Feb 27, 2023 1:59 pm

Here is my final call, and one that comes with a lot of uncertainty as a difference of a few miles, or just 1 hour longer of steady snow, could mean the difference of 2-4" in someones backyard.

I think @WinterColdandSnowisamyth made the point earlier today that 5" of snow could theoretically fall, but how much sticks and how much ends up being washed away from rain? GFS seems like an outlier right now with its massive totals over a widespread area. A combo of the NAM and EURO is probably a more realistic picture.

February 27th-28th 2023 Winter Storm - Page 3 2nd-call

February 27th-28th 2023 Winter Storm - Page 3 2nd-call

by **billg315** Mon Feb 27, 2023 2:14 pm

Tough event to predict but I really like Frank's final call map. I think this will be very close to what we see.

by WinterColdandSnowisamyth Mon Feb 27, 2023 2:19 pm

heehaw453 wrote:
sroc4 wrote:Dont panick too much yet folks. Here is the surface temps valid as of 2pm and then again by 7pm. Temps will drop again. Its all part of the plan. The details as to why I have been referring to the Kuchera maps is because the coastal plain will not likely see great ratios due to these marginal temps. You just cant look at the 10:1 maps. The latest Kuchera upgrades have def done much better this season. Again I know we all want 6+ but its not likely to be the norm along the coastal plain. IMHO. There will be however areas to over perform as well as underperform....happens every storm

Sroc this is about accumulations really. It will snow I have no doubt, but what I think is push comes to shove the snow depth algorithm is best for this event, not kuchera or 10:1. This is what I believe reality holds for this event.

Nope, this one goes to far to the downside especially for the northern areas. I still stick with the Kuchera map that Frank posted a little while ago. Seemed very reasonable with amounts from north to south.

by **sroc4** Mon Feb 27, 2023 2:27 pm

heehaw453 wrote:I'm watching this ULL. If it doesn't open up in the next hour or two it will have big impacts on the bad side for us.

The fact that we are even discussing accumulating snow with such a zonal flow across 97% of the CONUS is a bonus. In reality we shouldnt snow with this look at 500.
February 27th-28th 2023 Winter Storm - Page 3 500mb

February 27th-28th 2023 Winter Storm - Page 3 500mb

by **heehaw453** Mon Feb 27, 2023 2:48 pm

WinterColdandSnowisamyth wrote:
heehaw453 wrote:
sroc4 wrote:Dont panick too much yet folks. Here is the surface temps valid as of 2pm and then again by 7pm. Temps will drop again. Its all part of the plan. The details as to why I have been referring to the Kuchera maps is because the coastal plain will not likely see great ratios due to these marginal temps. You just cant look at the 10:1 maps. The latest Kuchera upgrades have def done much better this season. Again I know we all want 6+ but its not likely to be the norm along the coastal plain. IMHO. There will be however areas to over perform as well as underperform....happens every storm

Sroc this is about accumulations really. It will snow I have no doubt, but what I think is push comes to shove the snow depth algorithm is best for this event, not kuchera or 10:1. This is what I believe reality holds for this event.

Nope, this one goes to far to the downside especially for the northern areas. I still stick with the Kuchera map that Frank posted a little while ago. Seemed very reasonable with amounts from north to south.

We'll see. The GFS one backs it up too for the northern area and I have found it very good at these marginal temp events. I think it's reasonable to see ASL locales > 1200' get 6" +, but lower elevations I'm not so sure.

February 27th-28th 2023 Winter Storm - Page 3 Gfs169

by **sroc4** Mon Feb 27, 2023 2:51 pm