1003 replies to this topic

[NEOH]

OHweather, on 9 November 2011 - 01:48 PM, said:

The models have essentially remained unchanged since yesterday for Thursday night, and some of the short range meso-scale models are now out to Friday morning, adding some clarity to the situation.

The 12z NAM, 12z GFS, and 0z European model runs all show 850mb temps of -5 over the lake and much of Ohio by 0z Friday, and quickly advect in 850mb temps of -6 to -8 over the course of the evening. This is in response to an upper level shortwave and secondary cold front moving through the area Thursday evening. As the shortwave moves through, the models develop a deep cyclonic flow over the lakes and show an increase in mid level humidity, resulting in steep low level lapse rates, high inversions and some mid level moisture to help seed lake effect.



The 12z NAM skew-t for Cleveland right along the lake shore valid 9z Friday, courtesy of wunderground.com shows a relatively uniform WNWrly flow of 20-30 knots in the lowest 20k feet of the atmosphere, with reasonable moisture and instability up through about 13-14k feet. This moisture and instability go through the whole dendrite growth zone. This would certainly support lake effect activity through much of the night.

As the secondary cold front passes through Thursday evening, it is reasonable to assume that scattered showers might break out area wide across a good chunk of northern Ohio as some synoptic lift moves through. After this front passes, the flow will start shifting from westerly to WNWrly and potentially more NWrly by early Friday morning. Given a deep cyclonic flow with deep moisture through the lower-mid levels, high inversions and plenty of instability with lake-850mb delta-t’s of -16 to -18C and the lake-500mb differential around -40C, this supports robust lake effect development over the lake starting around 0z Friday.

Given the wind direction the best banding may initially be concentrated along the eastern lake shore. However, the winds will slowly gain more of a northerly component, shifting the initial band inland into the primary Snow Belt and perhaps favoring another convergence band for a period of time along the western lake shore into the southern/eastern suburbs. If the flow goes almost northwesterly like some models do show by early Friday, the convergence bands may dissipate and be replaced by more of a multi-band setup, which favors the higher terrain inland from the lake.

Accumulations remain tricky…temperatures will start out in the lower 40s Thursday evening which supports rain or mixed showers initially. However, with sufficiently cold temperatures not far above the surface I believe that it will not take long to switch to snow as the evening progresses. Areas along the lake shore and the lower elevations are the exception, where I’m not sure there will be a period of all snow or notable accumulations. Snow should be accumulating in the higher elevations by midnight Friday. My guess is areas above 800 feet will see some accumulations under any heavier bands and that areas above 1000 feet will do well.

The shifting of bands may make it hard for any one area to really cash in. However, the 12z NAM shows .1-.25” of liquid equivalent over most of the Snow Belt and the 12z NMM/ARW mesoscale models show a large area of .25”-.5”+ liquid equivalent. Given instability into the dendrite growth zone and a rather unstable environment I believe over a quarter inch of liquid equivalent could occur where bands persist, and I do think there could be decent snow rates in the higher elevations where the whole column will be at or below freezing overnight. So, I believe a general 2-4” seems possible above 1000’ from eastern Cuyahoga county eastward. Between 800-1000’ 1-3” seems possible in the Snow Belt. Lower elevations will likely remain too warm for much accumulation. The higher elevations in southern Cuyahoga, northern Medina, northern Summit and northern Portage counties could also see 1-3”, especially if winds do become more northwest overnight Thursday into early Friday. The event should wind down Friday morning.


My best guess at this time:

Excellent analysis. Thanks for putting this together. Your snow map looks good. I think one big factor is how quickly the ridging moves in from the SW. Even though my location is just over 1k ft... I'm actually hoping the snow does not stick. I'd rather it just rip the remaining oak leaves down so I can clean the yard and gutters for the last time this season.

[OHweather]

NEOH, on 9 November 2011 - 03:10 PM, said:

Excellent analysis. Thanks for putting this together. Your snow map looks good. I think one big factor is how quickly the ridging moves in from the SW. Even though my location is just over 1k ft... I'm actually hoping the snow does not stick. I'd rather it just rip the remaining oak leaves down so I can clean the yard and gutters for the last time this season.

Thanks!

It looks like the ridging will really want to build in Friday morning after 12z, although right now it looks like the best lake effect conditions will occur solidly in the overnight time period, which would favor accumulation assuming some decent bands set up.

I still have slight fears of a warm boundary layer really keeping things in check, especially if the winds turn more NWrly and blow the air over the 50 degree lake right on inland.

[Trent]

Using last November 6th as a proxy, snow started to stick around E 79th street in Cleveland. The difference between Warrensville Center and Richmond Roads was incredible, went from 2" to 7" for a nominal elevation gain.

At the lakeshore snow mixed in with the heavier returns and went back to rain when the intensity decreased. The WRF really pumps out moisture for the east side. The BUF mesoscale models will also be in range this evening.

[OHweather]

Trent, on 9 November 2011 - 03:23 PM, said:

Using last November 6th as a proxy, snow started to stick around E 79th street in Cleveland. The difference between Warrensville Center and Richmond Roads was incredible, went from 2" to 7" for a nominal elevation gain.

At the lakeshore snow mixed in with the heavier returns and went back to rain when the intensity decreased. The WRF really pumps out moisture for the east side. The BUF mesoscale models will also be in range this evening.

I had that event from last November in mind when drawing my map.

From the 5th into the 6th (overnight) there was 1-3" in the higher elevations above 1000', with relatively insignificant accums below 1000'.

The next day a much stronger lake enhanced band set up and crushed the east side into the Snow Belt, and areas a couple hundred feet lower got into the act as well.

Given the instability and similar temp profiles, resulting in the potential for rather intense bands for a time I think we might see areas that saw accums last November 6th during the day see accums this go around as well (elevation wise).

[NEOH]

Trent, on 9 November 2011 - 03:23 PM, said:

Using last November 6th as a proxy, snow started to stick around E 79th street in Cleveland. The difference between Warrensville Center and Richmond Roads was incredible, went from 2" to 7" for a nominal elevation gain.

At the lakeshore snow mixed in with the heavier returns and went back to rain when the intensity decreased. The WRF really pumps out moisture for the east side. The BUF mesoscale models will also be in range this evening.

I forgot that happened last November. Must be getting old. Shaker Heights was the jackpot area I believe. I remember having around 2-3 inches IMBY, yet about 1 mile west near Richmond/Cedar there was at least 6 inches.

[OHweather]

NEOH, on 9 November 2011 - 04:10 PM, said:

I forgot that happened last November. Must be getting old. Shaker Heights was the jackpot area I believe. I remember having around 2-3 inches IMBY, yet about 1 mile west near Richmond/Cedar there was at least 6 inches.

The gradient with that one was insane. You could drive up a 150 foot hill and go from nothing on the ground to 3"+...or drive a mile down the road and see a 3" difference due to the sharp cutoff to the precip. The snow level was obviously right at where much of the area is situated elevation wise, and the band had a very sharp cutoff, although the sharp cutoffs do happen from time to time

[Trent]

[Trent]

Regardless of whether it's snow or not, or how much accumulates inland, it will be fun to watch the evolutions of the bands.

[NEOH]

Trent, on 10 November 2011 - 07:29 AM, said:

Regardless of whether it's snow or not, or how much accumulates inland, it will be fun to watch the evolutions of the bands.

It will be interesting to see how this plays out. Winds are projected to be just north of due west 270-280... which would favor a single band, thus heavier precip. I believe the models had a more NW'erly flow yesterday.

[OHweather]

NEOH, on 10 November 2011 - 08:38 AM, said:

It will be interesting to see how this plays out. Winds are projected to be just north of due west 270-280... which would favor a single band, thus heavier precip. I believe the models had a more NW'erly flow yesterday.

The models are now taking until almost 4am Friday to turn the winds more northwesterly, thus potentially favoring a primary W-E convergence band for several hours. This could certainly warrant an advisory for Geauga and Inland Ashtabula Counties, with northeastern Cuyahoga being borderline due to lower elevation and proximity to the lake.

I still think the winds gain enough of a northerly component to dust the southern/eastern suburbs as well right around the morning rush with what's left of any bands from overnight.

[OHweather]

Just took a closer look at the models...there are some timing differences WRT how fast the winds shift...

All of the images are valid 6z Friday, from the most recent run of the model available as of this writing...

RUC:
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NAM:
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GFS:
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Euro:
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NMM:
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The short range, mesoscale models (RUC, NAM, NMM) seem to hang onto a more westerly flow for longer, while the GFS/Euro still show a more northwesterly flow taking over around 6z.

Given we are in the short range, I would tend to give the nod to the slower change in wind direction, although it will be interesting to watch.

If you quote this, please take out the images

[NEOH]

OHweather, on 10 November 2011 - 01:11 PM, said:

The models are now taking until almost 4am Friday to turn the winds more northwesterly, thus potentially favoring a primary W-E convergence band for several hours. This could certainly warrant an advisory for Geauga and Inland Ashtabula Counties, with northeastern Cuyahoga being borderline due to lower elevation and proximity to the lake.

I still think the winds gain enough of a northerly component to dust the southern/eastern suburbs as well right around the morning rush with what's left of any bands from overnight.

I wish the CLE WRF was operating properly on the website. It generally has a southern bias to the band location but can give you a general idea of where the bands will set-up. These early season LES events always have some surprises. I just don't see the winds coming around from any more that 270-280 direction. Classic primary band wind direction. Now the only questions are surface temps, when the winds turn, when ridging builds in . There are always more questions than answers when it comes to LES. If the BUF WFR data Trent posted verifies places from NE Cuyahoga through Northern Geauga will get blasted.

[OHweather]

NEOH, on 10 November 2011 - 02:46 PM, said:

I wish the CLE WRF was operating properly on the website. It generally has a southern bias to the band location but can give you a general idea of where the bands will set-up. These early season LES events always have some surprises. I just don't see the winds coming around from any more that 270-280 direction. Classic primary band wind direction. Now the only questions are surface temps, when the winds turn, when ridging builds in . There are always more questions than answers when it comes to LES. If the BUF WFR data Trent posted verifies places from NE Cuyahoga through Northern Geauga will get blasted.

It hasn't been for quite some time

FWIW, the 15z HRRR through 5z tonight sets up a primary band over eastern Cuyahoga and Geauga counties and deposits 4-5" of snow centered near Moreland hills through the end of that run at 5z.

The WRFs that I have seen do seem to favor the area you mentioned, and I might just have to take a drive late tonight or early tomorrow. I still think the southern and eastern suburbs get a taste, but probably don't see more than perhaps an inch. When the winds back is key...if it happens at 1am as opposed to 4-5am, that could make a huge difference.

[Trent]

Well the latest NAM shifts the winds a bit earlier. I can't wait to see how many tenths of an inch of LER I wake to. Unfortunately by the time I can drive to the east side tomorrow afternoon it will be gone.

Btw, how does this set up compare to the lake effect (rain) band overnight back on October 21, that gave me 0.80" inches.

[NEOH]

OHweather, on 10 November 2011 - 02:56 PM, said:

It hasn't been for quite some time

FWIW, the 15z HRRR through 5z tonight sets up a primary band over eastern Cuyahoga and Geauga counties and deposits 4-5" of snow centered near Moreland hills through the end of that run at 5z.

The WRFs that I have seen do seem to favor the area you mentioned, and I might just have to take a drive late tonight or early tomorrow. I still think the southern and eastern suburbs get a taste, but probably don't see more than perhaps an inch. When the winds back is key...if it happens at 1am as opposed to 4-5am, that could make a huge difference.

First soggy flakes of the year just fell at the office in Chagrin. I guess boundary temps won't be a concern later tonight . My home is near the 271/Cedar exit... my gut tells me I'm even too far south. It seems the models always want to turn the winds more NW'erly than what actually occurs. I remember LEK explained this awhile back. Something about lake induced troughing, along with the shoreline configuration keeping the winds more westerly than what the models show.

[NEOH]

Trent, on 10 November 2011 - 03:17 PM, said:

Well the latest NAM shifts the winds a bit earlier. I can't wait to see how many tenths of an inch of LER I wake to . Unfortunately by the time I can drive to the east side tomorrow afternoon it will be gone.

Btw, how does this set up compare to the lake effect (rain) band overnight back on October 21, that gave me 0.80" inches.

C'mon. Your in the game for tonight. Lakewood due east gets first measurable snowfall.

[OHweather]

NEOH, on 10 November 2011 - 03:20 PM, said:

First soggy flakes of the year just fell at the office in Chagrin. I guess boundary temps won't be a concern later tonight . My home is near the 271/Cedar exit... my gut tells me I'm even too far south. It seems the models always want to turn the winds more NW'erly than what actually occurs. I remember LEK explained this awhile back. Something about lake induced troughing, along with the shoreline configuration keeping the winds more westerly than what the models show.

Right now I think the 322 corridor may get hit hardest...probably from Mayfield points east. I remember that explanation from way back on eastern, faintly. Will really just have to wait and see where the banding sets up, although right now signs are pointing to a classic W-E convergence band, slowly sagging south through the night into the AM.

Saw a rain shower a little bit ago, no snow here yet. Sun peaking back out.

[OHweather]

Lake effect snow advisory Ashtabula inland, Erie Inland, PA and Crawford, PA.

CLE does not understand how banding will form with a westerly flow, they have had issues with this before. Geauga needs to be in that advisory.

[NEOH]

OHweather, on 10 November 2011 - 03:24 PM, said:

Right now I think the 322 corridor may get hit hardest...probably from Mayfield points east. I remember that explanation from way back on eastern, faintly. Will really just have to wait and see where the banding sets up, although right now signs are pointing to a classic W-E convergence band, slowly sagging south through the night into the AM.

Saw a rain shower a little bit ago, no snow here yet. Sun peaking back out.

Even though I live less than a mile south of 322, I'm hoping its north of there honestly. Too much yard work left to do this weekend.

My call is that from Trents backyard through Chardon gets hit. Winds are fairly light so there might a nice covergence area along the lakeshore keeping the snow from pushing south.

[OHweather]

NEOH, on 10 November 2011 - 03:37 PM, said:

Even though I live less than a mile south of 322, I'm hoping its north of there honestly. Too much yard work left to do this weekend.

My call is that from Trents backyard through Chardon gets hit. Winds are fairly light so there might a nice covergence area along the lakeshore keeping the snow from pushing south.

I don't see Trent getting a good hit unless some heavy rates set up shopm over him for a few hours, the lake is just too warm IMO.

[NEOH]

OHweather, on 10 November 2011 - 03:44 PM, said:

I don't see Trent getting a good hit unless some heavy rates set up shopm over him for a few hours, the lake is just too warm IMO.

Even though lake temps are warm dynamic cooling should do the job. It's going to take heavy precip rates, but that's what I'm expecting with the primary band set up. If multi-bands set up forget about it.

My post about the jackpot area was mostly a joke. My yard is a disaster after last nights winds so I'm trying to wish the snow away. The oaks lost a lot of leaves. Gutters are overflowing with leaves. I would hate to waste the weekend watching a few inches of slushy snow melt.

[wxdudemike]

Quite a few reports of snow in Cincinnati this afternoon. Hoping to see some here in Columbus!

[dta1984]

OHweather, on 10 November 2011 - 03:24 PM, said:

Right now I think the 322 corridor may get hit hardest...probably from Mayfield points east. I remember that explanation from way back on eastern, faintly. Will really just have to wait and see where the banding sets up, although right now signs are pointing to a classic W-E convergence band, slowly sagging south through the night into the AM.

Saw a rain shower a little bit ago, no snow here yet. Sun peaking back out.

I live right off 322 near Gates Mills, i'll keep everyone posted with what I see.

[OHweather]

dta1984, on 10 November 2011 - 05:16 PM, said:

I live right off 322 near Gates Mills, i'll keep everyone posted with what I see.

My jackpot zone actually means something now

I'm sure between the few of us here in the Cleveland metro at least one of us will see something interesting over the next 12-18 hours.

[OHweather]

Shortwave making some headway, looks to be moving into SE MI now, with yes, a more NW flow behind it...still will be a while for NE OH until that gets here...looks like some bands are trying to flair up over western Lake Erie...

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[Trent]

OHweather, on 10 November 2011 - 06:55 PM, said:

Shortwave making some headway, looks to be moving into SE MI now, with yes, a more NW flow behind it...still will be a while for NE OH until that gets here...looks like some bands are trying to flair up over western Lake Erie...

Any band that sets up overnight will produce accumulations. BKL reporting light snow this hour. I think Geauga County should do well.

[dta1984]

Just looked out the window and grass looks to be covered, but nothing on the roads. . Hard to telll how much, i'm in a high rise.

[Shsg Falls]

dta1984 said:

1320982684[/url]' post='1110886']
Just looked out the window and grass looks to be covered, but nothing on the roads. . Hard to telll how much, i'm in a high rise.

I was in a airplane over Lake Erie at 10:25 pm headed to the East Coast, I saw one lightning strike in the lake band east of downtown. Hard to tell if the lightning was offshore or in Lake County as it was embedded in the cumulus cloud. Just looked like one band at that time. AKR, CAK and YNG looked clear.

[OHweather]

Been snowing lightly here the last half hour to 45 mins. A couple of moderate bursts. There is a very light dusting on cars, grass, and roofs.

Looks like the main band may be shifting into Cuyahoga, extreme northern Summit and northern Portage Counties, so those areas may pick up some accums through day break. A new radar image came in while I typed this and there is clearly another primary band developing here.

Radar VAD data from CLE shows the winds have stopped shifting more northerly over the past hour. The latest meso-analysis loop shows that the northerly wind shift may have slowed the past hour, and the lastest RUC essentially maintains the flow WNWrly like it is now for a few hours, then very slowly starts to back the flow more towards the west after about 6am. Water vapor imagery shows dry air air moving into western Michigan. This corrisponds well with significantly weaker echoes off of Lake Michigan. I'd expect the air to start drying here around 7-8am.

Essentially, areas that get under a band during the next half hour or so may cash in somewhat through the morning rush...1-3" of accumulation seems possible through day break where any bands set up...best guess is this will occur over northern Lorain county, Cuyahoga county, northern Summit County, northern Portage, and Geauga counties.

Saw CLE added lake and Geauga to the advisory which is a good move. Will be up in a few hours, time to sleep now.

[OHweather]

Half an inch here in Reminderville. Still some on and off flurries. Am leaning against a drive to Chardon, I need to catch up on sleep and have work in 4 hours.

Edit: Although, radar is estimating over half an inch of liquid equivalent up near highway 6 in northern Geauga County.

Edit 2: After further review, I'm a complete weenie and am driving up to northern Geauga County.

[Trent]

OHweather, on 11 November 2011 - 07:25 AM, said:

Half an inch here in Reminderville. Still some on and off flurries. Am leaning against a drive to Chardon, I need to catch up on sleep and have work in 4 hours.

Edit: Although, radar is estimating over half an inch of liquid equivalent up near highway 6 in northern Geauga County.

Edit 2: After further review, I'm a complete weenie and am driving up to northern Geauga County.

After perusing the traffic cameras this morning. There appeared to be about 3" on the ground in Concord. I woke up in the middle of the night and saw a dusting on the ground, it has since melted. Looks like CLE picked up 0.09" liquid equivalent, so it I'm curious if they will report 0.9" of snow (the traffic cameras on 71 near the airport still show snow on the ground). Otherwise, it seemed the band never really got its act quite together.

[OHweather]

Trent, on 11 November 2011 - 07:46 AM, said:

After perusing the traffic cameras this morning. There appeared to be about 3" on the ground in Concord. I woke up in the middle of the night and saw a dusting on the ground, it has since melted. Looks like CLE picked up 0.09" liquid equivalent, so it I'm curious if they will report 0.9" of snow (the traffic cameras on 71 near the airport still show snow on the ground). Otherwise, it seemed the band never really got its act quite together.

The W-E band held on as long as it could along the eastern lake shore and the northern primary snow belt, as soon as the winds were too northerly it rapidly pushed south and weak multi-bands took over. The WNW-ESE band set up very briefly and then dissipated.

If I see even 4" it will be worth the drive. Can't find a camera so I'm hoping I can get pics off my windows phone onto the computer, if there's anything good.

It's early November so I'm not too heart broken, just happy to see flakes.

[NEOH]

Picked up a solid inch last night. Mostly on the grass, rooftops, cars etc. Nice little appetizer for what is to come. Snow should be gone by the end of the day.

I'm really surprised that a more substantial band didn't form. I didn't even think to take a look at the shear so I'm curious as to what limited the band development. Looking at the radar loop it looks like the wind shifted pretty quickly... much more NW than I was expecting.

[OHweather]

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Am at Punderson state park, solid 2" here measured on a picnic table. The secondary roads do have a little snow on them out here.

[OHSnow]

YNG had 0.14" of precip. last night, including 0.11" between 5 and 6 AM. The airport reported one inch of snow during that hour. Will be interesting to see what the final total is... probably about 1.4" (or 10/1) given the marginal temps right around freezing.

METAR KYNG 111051Z 25007KT 1SM -SN BKN006 OVC011 M01/M02 A2985 RMK AO2 SLP119 SNINCR 1/1 P0011 T10061017 $