Northern Ohio Obs/Discussion Part 2

[NEOH]

9 minutes ago, dta1984 said:

Les watch out.   Cle mentions w then wnw winds.   Hoping for a little more n wind than last time.

Just checked bufkit and winds do come around on the NAM primarily from a 280 wind direction... for quite some time. While the GFS brings winds around from 290 - 300 for extended period of time. I think the big difference between this event and last week is there won't be a trough stalling over the lake preventing the winds from turning.

[dta1984]

11 minutes ago, NEOH said:

Just checked bufkit and winds do come around on the NAM primarily from a 280 wind direction... for quite some time. While the GFS brings winds around from 290 - 300 for extended period of time. I think the big difference between this event and last week is there won't be a trough stalling over the lake preventing the winds from turning.

Definitely good news !

Out of curiosity . ...what causes some events to be a single dominant band (like last week) vs a more multi band setup?  

[OHweather]

This will be an interesting event...

Things will initially get going on Wednesday up towards Buffalo with a SWrly flow. The first trough drops across the lake Wednesday mid to late evening and brings the winds around to W or WNW. Given the extremely strong temp gradient between over water and inland, along with higher pressure nosing into the OV, I expect this trough to get hung up near the lakeshore, perhaps close to where the mega band set up with the last event for several hours Friday evening. Mean winds on the NAM look a few degrees more northerly, so maybe it can setup a couple miles farther south, but I sort of doubt that a band sets up over say the Garfield to Solon corridor Wednesday night into Thursday. Although the incoming arctic airmass is characteristically dry, the flow will be very favorable for involving a Lake Michigan connection, and the very well aligned flow over Lake Erie will help any bands be more organized. Instability will also be extreme Wednesday night.

Another shortwave/vortmax rotates around the larger trough and moves over Lake Erie/NE OH early Thursday. This will probably briefly add some larger scale lift and could really cause lake effect to rip and rip hard early Thursday. The winds do go more WNW behind this trough on Thursday, but with such cold air inland and higher pressure nosing in I doubt the band sinks south. I could see it setting up a few miles farther south than the last event, but again I have my doubts for how much farther it sets up. If it does set up farther south this could involve the western lakeshore, downtown, and the 480/422 corridors in eastern Cuyahoga County. Not 100% sold on that but it appears more possible than the last event.

Ridging noses in Thursday evening which should cause a band to slowly shift north and probably gradually weaken by Friday morning, ending the event as winds turn southerly.

As for amounts...definitely think there's potential for 2 to 4" per hour snow rates in the band Wednesday night into Thursday...particularly Thursday morning as the shortwave moves by. This is because of upstream moisture, low shear, and some of the most prolific instability I've ever seen over Lake Erie with temperatures this cold. The airmass will be on the cusp of being "too cold" for great ratios, but with such warm waters I'd have to imaging a good band would easily push the DGZ right up into the cloud layer. Ratios of 30-40:1 seem likely. With a band possibly locking in or moving very slowly Wednesday night, amounts of over a foot could occur by Thursday morning. If the band locks in for most of the night, amounts overnight could exceed 18". On Thursday the band may wiggle south and similar snow rates may continue for a good chunk of the day. If this occurs, those who miss out Wednesday night could get a nice consolation. If the high pressure and extreme cold over land cause the band to struggle to move south, then some areas could double dip (again) and see a very impressive total. We shall see what happens, still some time to adjust.

[OHweather]

12z NAM was definitely a bit more encouraging in terms of bringing the winds around to the WNW...we'd definitely get the band to set up farther south if that verified. Hopefully it's a trend and not a one run blip. The GFS consistently brings winds around too far NW with lake effect events so I've started ignoring it lately.

[London snowsquall]

5 minutes ago, OHweather said:

12z NAM was definitely a bit more encouraging in terms of bringing the winds around to the WNW...we'd definitely get the band to set up farther south if that verified. Hopefully it's a trend and not a one run blip. The GFS consistently brings winds around too far NW with lake effect events so I've started ignoring it lately.

Getting a more northerly flow would certainly be nice.  The last event missed us to the north just like most of the Ohio posters.   

[NEOH]

43 minutes ago, OHweather said:

12z NAM was definitely a bit more encouraging in terms of bringing the winds around to the WNW...we'd definitely get the band to set up farther south if that verified. Hopefully it's a trend and not a one run blip. The GFS consistently brings winds around too far NW with lake effect events so I've started ignoring it lately.

That's good news. What do use for looking at wind direction? I use the bufkit datawarehouse output. The 12z NAM shows a consistent 280-290 flow from 04 12/15 through 02 12/16. That wind direction is a pretty good signal for a single band.

Also, now that the lake water has cooled off (especially out west), I wonder if the higher wind speeds will offset the land breeze component.

[NEOH]

2 hours ago, dta1984 said:

Definitely good news !

Out of curiosity . ...what causes some events to be a single dominant band (like last week) vs a more multi band setup?  

I'm no expert... but I think the fetch and convergence. Our biggest events seem to be when a single band forms on a WSW flow then pushes inland as winds veer. Upstream connections will probably dictate where the band sets-up.

[NEOH]

I know nothing about the NAM3km Para on Tropical tidbits but wow what a recent run. Here's the snowfall and precip... right around 2". Nice lake michigan connection.

 

[NEOH]

1 hour ago, NEOH said:

I know nothing about the NAM3km Para on Tropical tidbits but wow what a recent run. Here's the snowfall and precip... right around 2". Nice lake michigan connections.

 

 

Here's total precip...

 

[Buckeye_Weather]

Looks good for eastern Cuyahoga, right where I am in Shaker Heights

[Trent]

1 hour ago, NEOH said:

I know nothing about the NAM3km Para on Tropical tidbits but wow what a recent run. Here's the snowfall and precip... right around 2". Nice lake michigan connection.

 

That's pretty much an ideal run for most of us on here. Let's hope it verifies. 

[dta1984]

1 hour ago, NEOH said:

Here's total precip...

 

Wow let's lock that in!

Similar band placement to the DEC 2010 one that dumped on downtown out to Solon during the day.

[dta1984]

55 minutes ago, Trent said:

That's pretty much an ideal run for most of us on here. Let's hope it verifies. 

Haha that's true, covers most of the posters!

[NEOH]

42 minutes ago, dta1984 said:

Haha that's true, covers most of the posters!

No doubt. After being skirted to the north last year and this year we could use a good one. The NAM performed pretty well with last weeks event so hopefully it has the same success. We even have a little buffer should there be a SW bias to the precip placement.

[NEOH]

Noticeable shift south with precip on the 18z run. Reminderville jackpot . If there is a SW bias its good to be on the north side. Check out Lake Huron... those areas would be buried.

 

 

 

[dta1984]

12 minutes ago, NEOH said:

Noticeable shift south with precip on the 18z run. Reminderville jackpot . If there is a SW bias its good to be on the north side. Check out Lake Huron... those areas would be buried.

 

 

 

Check the 4km NAM on tropicaltidbits.  It also loOKs good. 

[Cleveland_WX]

Snow Showers in Cleveland. 

[NEOH]

Surprised CLE hasn't upgraded the watches at this point. The mesoscale models continue to show a high impact event from the near west side through central/southern geauga county. Wonder if any ice was able to form last night on the western basin with temps in the single digits.

[OHweather]

An unseasonably deep upper level trough will drop into Ontario and Quebec through Friday, ushering in the coldest air of the season thus far and aligning the winds out of the west-northwest across the Great Lakes, setting off another round of heavy lake effect snow.

Lake effect snow will intensify this afternoon as winds go southwesterly and allow a strong single band to form over the lake towards Buffalo. The flow is somewhat sheared, however an increase in moisture and lift ahead of a shortwave rotating around the upper level trough and moderate instability developing over the lake should allow snow rates of over 1” per hour to develop with the band as it moves off the eastern end of the lake this afternoon into locations near and just south of Buffalo.

The aforementioned shortwave will move over Lake Erie and NE Ohio/NW PA/SW NY between 0z-6z/7pm-1am Wednesday evening and push winds to a more WNW direction. As this shortwave approaches, even colder arctic air will move in allowing instability to decrease, while at the same time inversion heights come up. A connection to Lake Michigan will likely develop and larger scale lift from this first shortwave and another one will help enhance lake effect processes Wednesday evening through Thursday morning.

Instability will increase this evening, with lake to 850mb temp differentials increasing to 22C+, lake to 700mb temp differentials increasing to 32C+, and lake to 500mb temp differentials increasing to 40-42C. These values are all extreme and along with equilibrium levels on the models of over 10k feet suggest any snow band will be very intense and likely accompanied by some sporadic lighting. The combination of some moisture from the shortwave trough and a connection to southern Lake Michigan will increase moisture depth to around 8k feet. Snow ratios should be fantastic tonight with good RH and strong lift focused on the DGZ. Winds are a little bit on the strong side, but a very well aligned flow, upstream connections, and a favorable long fetch with a W to WNW flow and good convergence along the shoreline should mitigate the stronger winds.

The first trough this evening doesn’t have appear to enough oomph to push inland, so the band may get locked in or move very little for several hours late this evening into early Thursday morning. With rising pressure over the Ohio Valley and very cold, dry air inland along with WSW winds, this band will likely setup near or along the lakeshore and into the primary Snowbelt. This wind profile is fairly similar to the one that locked in a band along route 6 with the last event, although with somewhat stronger WNW winds over water, which may allow the band to set up a couple of miles farther south tonight. This could bring downtown Cleveland, the immediate western lakeshore, more of eastern Cuyahoga County and more of southern Geauga County into play tonight. I don’t expect a huge difference in placement from the last event, but that couple of miles could make a big difference to some heavily populated areas that were on the edge of the last event. The winds wiggle a little bit between late this evening and Thursday morning, but not a ton, so the convergence near the lakeshore and fairly steady winds should cause the band to drift over similar areas for most of the night tonight.

The next shortwave and surface trough will push SE across the lake between 5am and 10am Thursday morning. There appears to be a somewhat stronger push of NW winds behind this trough, so it will likely push the snow band inland before perhaps breaking it up into multi-bands for a time later Thursday morning.

The environment will be very favorable for heavy lake effect snow as this second trough passes; wind shear will be minimal, although wind speeds again are maybe 5-10 knots faster than is preferable. Lake to 850mb temp differentials are expected to exceed 25C by Thursday morning, with 700mb differentials exceeding 35C. These are both incredible differentials driven by the arctic airmass moving over a still somewhat warmer than average lake, with lift from the shortwave and an upstream connection to Lake Michigan offsetting the drier arctic airmass.

The trough will likely push through quickly enough that the band doesn’t sit on any one spot for more than a couple hours (although we’ll have to watch and make sure it doesn’t get hung up just inland), however the instability/moisture profile combined with the minimal wind shear, strong lift and good RH in the DGZ, and very strong convergence expected between 10kt WSW winds south of the trough and 30kt WNW to NW winds over the water north of the trough, suggests that very heavy snowfall is expected. Instantaneous snowfall rates to 2 to 4” per hours seem likely should this band come to fruition, however it’s questionable how long these rates sit over any one spot. The bad news is this band looks to move across a good portion of the Cleveland metro near rush hour, and even if those snow rates don’t last long they can create quite a mess.

Behind the trough Thursday morning, winds are expected to go WNW to even NW, and this should push the primary band inland and break it up into multi-bands for at least a few hours. This will likely spread some lighter accumulations into the secondary Snowbelt and give a break to the northern primary Snowbelt. This flow could bring upper Great Lake connections (perhaps Superior/Michigan) into NW PA, and also hits the upslope areas well there, so moderate accumulations could continue in NW PA behind this trough in the higher terrain, with activity tapering considerable near and north of I-90. The Lake Michigan connection should shift south of Lake Erie for a few hours later Thursday morning and early afternoon in the more WNW to NW flow, although it’s possible upslope in the central highlands allows for a period of snow showers as the Lake Michigan connection aims towards that general area.

Some negatives will develop behind this second trough; the fetch will become shorter and the airmass will dry out, both due to the upstream airmass becoming even drier and the Lake Michigan connection shifting south. This drier airmass, shorter fetch, and somewhat colder temperatures will likely make it hard for intense bands to develop. Outside of any intense bands, it will be cold enough to limit snow growth and hence keep ratios in check. So, accumulations could really slow down for a time later Thursday morning into the afternoon. If a heavier multi-band can set up, then latent heat release within the band may push the DGZ into the clouds and allow for locally higher ratios within any band; due to the flow though it may be a struggle to see good bands develop for a time on Thursday.

The surface high will really start pushing in Thursday evening, allowing temps to crater over land to near 0 and also causing SWrly winds to develop on land. This will tighten up convergence again near the lakeshore and in the Snowbelt, and may also re-develop a Lake Michigan connection for a time:

This combination of renewed convergence and some improved low level moisture could allow a band to re-develop from northern Cuyahoga County east into southern Lake and Geauga Counties Thursday evening. Winds will slowly continue to back as high pressure noses in, so this should cause the band to slowly shift northeast through the night. With that said, the winds on land may not get strong enough to push the band completely over the lake until Friday morning.

Forecast soundings from within the potential snow band on hi-res models show inversion heights remaining near 700mb through Thursday evening before really dropping off, with good moisture and lift (omega) in the DGZ. This could allow a decent band to still produce 1-2” per hour snow rates for a time Thursday evening closer to the lake. With that said, inversions do crash later Thursday night and high pressure will try pushing the band north, so amounts Thursday night will likely be held to less than 6” where the band is more persistent, and much of that could fall during the first half of the night.

So, as for amounts…it is quite possible that the lakeshore from eastern Lake County east through Erie County struggle to see a ton with this one. I expect a good burst in the primary Snowbelt from northern Cuyahoga County east/north as the single band pushes onshore with the first trough tonight. With convergence quite possibly hanging close to the lake and into the Snowbelt tonight behind the first trough, along with a Lake Michigan connection and very favorable conditions for heavy lake effect snow, it seems possible that a heavy band with 1-2” per hour snow rates persists for several hours tonight. With WNW winds over water, it is possible this band affects the lakeshore in Cuyahoga County before moving inland into the eastern suburbs, southern Lake County and a good portion of Geauga County. With a long fetch into the higher terrain of NW PA, those areas may do decently too. The band may wiggle some, which if it occurred may keep amounts through 5AM Thursday in the 4-8” neighborhood where the band affects most…however, if the strong convergence causes the band to be more impervious to small wind direction changes, the band locking in and producing up to a foot by 5AM Thursday isn’t impossible in a small area.

I expect the snow to intensify across the board between 5-9AM Thursday as the next trough passes through. Snow rates could increase to 2-4” per hour in the dominant band. This band will probably initially intensify in the northern Snowbelt before slipping south through 9AM Thursday and quite possibly breaking up into multi-bands late Thursday morning as the winds go WNW to NW. This band may move quickly enough that it only drops 1 to 4” of snow as it goes, but this could affect parts of Lorain, much of Cuyahoga, southern Lake, much of Geauga, southern Ashtabula, parts of NW PA (inland especially), and perhaps even northern Medina, Summit, Portage, and Trumbull with a burst of very heavy snow during rush hour. This could be a very high impact event. If the band gets hung up somewhere at all, even for just 2 or 3 hours, the very heavy snow rates could allow it to quickly drop over half a foot over a narrow corridor. This may happen from the western lakeshore into SE Cuyahoga County for a time, due to the winds paralleling the shoreline there for a time and perhaps causing the convergence to “stick” to the lakeshore for a couple of hours.

The snow should diminish across the board late Thursday morning and into the afternoon. The instability suggests heavy squalls may still occur, but the snow bands will likely break up by then, and the colder/drier arctic air may stunt snow growth outside of any good bands. Some areas, such as the higher terrain in the secondary Snowbelt, Geauga County, and particularly NW PA may pick up 1-2” late Thursday morning and afternoon, but unless we get a band to hang on from the west side into say Medina/Summit Counties…which does sometimes occur with this type of flow, but is hard to predict ahead of time…I doubt accumulations will be particularly impressive in this timeframe.

Signs do point towards a single band re-developing late Thursday afternoon and into the evening as winds inland turn SW and increase convergence along the lakeshore into the Snowbelt, while a potential Lake Michigan connection also tries to redevelop. Inversion heights will start to lower and moisture will be more limited than say tonight, however intensifying convergence along with weakening winds (increased residence time over the lake) could still allow a decent band to develop for a time. This band may initially develop from the western lakeshore out east towards Chagrin or Solon before gradually moving north. Snow rates of 1” per hour or more may still be supported Thursday late afternoon and evening if we get a good band to develop, but the band will likely be slowly moving, and conditions appear to degrade significantly for lake effect after midnight, so additional amounts from this band will likely be held to 2 to locally 6”.

Storm totals may exceed a foot where the band is most persistent tonight into early Thursday, and where the snow band tomorrow evening affects. I doubt amounts exceed 18” due to the bands likely moving around/breaking up at times through the event. I did include decent accumulations on the western lakeshore, as convergence could be strong in that area at times and allow for banding there. The southwest edge is as always not high confidence.

Map:

 

Also, I know a couple of you asked me questions yesterday, when I get time today I will try to respond. Was not home until about midnight last night.

[dta1984]

Fantastic ohweather! Should be a fun spread the wealth event.  I'm definitely hoping that heavy band doesn't set up so far north again though.  

[NEOH]

Nice forecast as usual. Your map isn't too far from CLE's latest... it will an interesting event to follow. The models show anywhere from .40  to .75 of precip in this area so with the high ratio's those amounts wouldn't be hard to reach... Provided the band doesn't set-up North of here again.

 

 

[NEOH]

18z run of the NAM was pretty good. 3km has a nice 1" bullseye through the southeast part of Cuyahoga and southern Geauga. The 4km is a litte more stingy on precip with .50", and a little further north as well.

[OHweather]

Pretty good signs for a band across Cuyahoga during the AM rush. Spots will probably hit warning criteria anyways and this looks like a potential high impact event...so I don't agree with CLE only going with an advisory. The AFD wasn't much help either. 

[Trent]

29 minutes ago, OHweather said:

Pretty good signs for a band across Cuyahoga during the AM rush. Spots will probably hit warning criteria anyways and this looks like a potential high impact event...so I don't agree with CLE only going with an advisory. The AFD wasn't much help either. 

It seems they're going much more conservative with headlines for Cuyahoga County this year. It almost feels like they are doing headlines that are "county average" versus "maximum snowfall in the county" this year. It certainly makes it difficult for a county with over a million people that has drastically different weather by the mile.

I'm optimistic here along the lakeshore, but I've quickly learned that no set-up is ever a lock for snow here. I think accurately forecasting lake effect snow accumulations for areas outside the typical high elevation primary belt is a much more difficult task than forecasting for a place like Chardon. 

[OHweather]

2 minutes ago, Trent said:

It seems they're going much more conservative with headlines for Cuyahoga County this year. It almost feels like they are doing headlines that are "county average" versus "maximum snowfall in the county" this year. It certainly makes it difficult for a county with over a million people that has drastically different weather by the mile.

I'm optimistic here along the lakeshore, but I've quickly learned that no set-up is ever a lock for snow here. I think accurately forecasting lake effect snow accumulations for areas outside the typical high elevation primary belt is a much more difficult task than forecasting for a place like Chardon. 

I think the trend for Cuyahoga started a couple of winters ago...there was one point where they'd throw the whole county an advisory bone when a small part of it may get 3-5", and have certainly backed off of that recently. There are pros and cons to both ways of doing things (county average vs county max snowfall)...my general feeling is you can't not warn people who will see heavy snow for the sake of not warning people who won't see snow. If it's a situation where a small part of the county may squeak out a certain criteria and the vast majority won't, I'm ok with forgoing the headline, but if it's even a quarter of the county I think it justifies the headline. Impact is important too...is the rest of the county seeing 3" at 2am or during rush hour? Last weekend's event really only affected about a quarter of the county with warning criteria snow, but I think everyone agrees that not issuing the warning would've been ridiculous.

I think the ultimate solution is breaking Cuyahoga County into multiple forecast zones (which will not happen) or lake effect snow advisory/warning polygons (which probably will happen).

[NEOH]

Winds have really picked up the past hour. It will be interesting too how far the bands push inland. 

[IWXwx]

1 hour ago, Trent said:

It seems they're going much more conservative with headlines for Cuyahoga County this year. It almost feels like they are doing headlines that are "county average" versus "maximum snowfall in the county" this year. It certainly makes it difficult for a county with over a million people that has drastically different weather by the mile.

I'm optimistic here along the lakeshore, but I've quickly learned that no set-up is ever a lock for snow here. I think accurately forecasting lake effect snow accumulations for areas outside the typical high elevation primary belt is a much more difficult task than forecasting for a place like Chardon. 

It's too bad they can't issue polygon warnings like they do for severe weather. After all, why treat winter weather differently? It may not be needed for synoptic snows, but LES is often so geographically specific, it would be warranted.

EDIT: I just saw OHweather recommend the same thing in his last sentence. It only makes sense.

[OHweather]

34 minutes ago, IWXwx said:

It's too bad they can't issue polygon warnings like they do for severe weather. After all, why treat winter weather differently? It may not be needed for synoptic snows, but LES is often so geographically specific, it would be warranted.

EDIT: I just saw OHweather recommend the same thing in his last sentence. It only makes sense.

I definitely think LES polygons are coming. BUF is testing them for the second winter in a row, and I've heard rumblings about it from mets in other parts of the Great Lakes. I'm not sure when, but it's the next logical step. It may come out as a part of the larger "hazard simplification" project (rolling my eyes) that they're working on now.

[Cleveland_WX]

Heavy Band Over Ohio City in Cleveland's west side.. Blizzard conditions!! 

[Trent]

1 hour ago, Cleveland_WX said:

Heavy Band Over Ohio City in Cleveland's west side.. Blizzard conditions!! 

It's an unbelievable sight out there this morning. Now if only this band can become stationary for most of the day. 

A chilly 13 degrees outside with 1/16 mile visibility IMBY.