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Lets Talk Winter! Ohio valley and surrounding States


Steve

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We seem to get our heaviest lake effect snow band here in Chagrin Falls when the winds at the lowest levels are 290° to 310°. If anyone is in the region "snow chasing" feel free to stop by for coffee!

My office is in Chagrin off of E Washington. Its a great place for NW'erly wind events. Even with strong winds Chagrin is far enough inland to cash in on heavy snow.

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My office is in Chagrin off of E Washington. Its a great place for NW'erly wind events. Even with strong winds Chagrin is far enough inland to cash in on heavy snow.

I wonder if the winds will be too strong until Monday evening/night to get a good band setup. They don't seem to drop below 40 knots at 850 mB until Monday evening:

post-7331-0-96942300-1325360813.png

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dont look now but the gfs is showing an arctic surge in the long range...would be great to see some pronlonged snowy weather...

Cool. The GFS has been outperforming the ECMWF as of late (see post #392 in this thread, the ECMWF has not verified at all in it's New Year's Forecasts - it was showing Sunday temperatures approaching 60° for Cleveland 10 days ago).

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Looks like the snow will hold off for Sunday. The bands won't start to drop into Cuyahoga/Geauga Counties until Monday morning. Still 36 hours out from the main show, so lots of small scale parameters yet to be figured out.

Here's to hoping for a less wet, more white New Year!

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Looks like the snow will hold off for Sunday. The bands won't start to drop into Cuyahoga/Geauga Counties until Monday morning. Still 36 hours out from the main show, so lots of small scale parameters yet to be figured out.

Here's to hoping for a less wet, more white New Year!

Hopefully the winds can turn quicker than anticipated. Not likely though. Winds seem to have a hard time turning until a trough forces them to. Heavier snows will probably delayed until the arctic front at this point... Monday night? meh -- there's my negative post for the day. I really thought the winds would come around to a favorable direction much sooner.

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This run shows a primary band developing by 11 pm Sunday night. Here is the last frame at 1 am on Monday, with winds still having a SW component.

wrf_wind-precip01_F36.gif

The question then becomes, how long does it take before it swings south and how long will it sit over us before dissipating and disorganized bands set up with the NW flow?

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Hopefully the winds can turn quicker than anticipated. Not likely though. Winds seem to have a hard time turning until a trough forces them to. Heavier snows will probably delayed until the arctic front at this point... Monday night? meh -- there's my negative post for the day. I really thought the winds would come around to a favorable direction much sooner.

Watching the 0z NAM role in, it continues bringing the synoptic flow around to the due west by 10am Monday and WNW by 1pm Wednesday, and starts slowly sagging the lakeshore convergence zone south after 12z. The model appears to hold the winds WNW through early evening when the arctic front brings winds around to the NW and then NNW by late Monday night. I still think snows start moving into the eastern suburbs from north to south Monday morning and into northern Summit/Portage counties by noon Monday. After the convergence band moves south things might be somewhat disorganized until I think we see a zone of moderate to heavy orographic lift snow over the higher elevations over eastern/southern Cuyahoga county, Geauga County and inland Ashtabula into NE Medina and northern Summit/Portage/Trumbull counties. Indications are pointing towards a lake Huron connection definitely getting into Ashtabula County and potentially as far west as Lake/Geauga/Portage/Trumbull Counties. My first guess is 6-12" southern/eastern Cuyahoga County, northern Summit/Portage/Trumbull Counties and 8-14" over Geauga and Ashtabula Counties. 3-6" northern Cuyahoga, Lake and northern Ashtabula counties and 2-4" for western Cuyahoga and Lorain County storm total...will try to refine after tonight's 0z runs since I work at 7am tomorrow and am staying home tonight.

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Lake Erie lake effect snowstorm 1/1-1/4:

The setup:

post-525-0-76846900-1325403259.gif

A large upper level trough will slow down and amplify over the northeast. A strong surface low pressure generated by the trough will move through the northern Great Lakes on Sunday and move off towards the Canadian Maritimes by Monday night. Cold high pressure—up to 1040mb—will dive south into the Plains and then slowly begin moving into the Great Lakes Monday night and Tuesday, effectively cutting off the lake effect over Lake Erie by Tuesday evening. The amplifying trough will force a shortwave south through the lower lakes Monday afternoon and evening, ushering in the coldest air of the season with 850mb temps dipping to as cold as -18C by Tuesday morning over Lake Erie.

Under the trough, deep synoptic moisture will help seed lake effect, low-mid level vorticity will remain high which will contribute to low level lift, and low level winds will be reasonably well aligned (generally 30 degrees or less of shear in the lowest 10k feet of the atmosphere).

Specifically for northern Ohio, things should start firing up around 1am Monday. The synoptic flow will initially start out WSW, which will aid in creating convergence along the eastern lakeshore. With water temperatures in the western basin hanging around +2C and at +4 east of Lorain, it will take 850mb temps of -9 to -11C to see sufficient delta T’s for true lake effect convection. We should attain this very late Sunday evening or just past midnight Sunday night:

post-525-0-13032900-1325403301.png

Although the mid level flow will be WNW by this point, the synoptic low level flow will still be WSW and only slowly start gaining a more northerly component into Monday morning. The flow is a little fast, but convergence usually develops along the lakeshore due to the temperature differencial between the cold air over land and the warmer air over the lake. In addition instability will become moderate by Monday morning, the flow is well aligned, and the boundary layer is deep and very moist, as shown on the Euro above. The Euro, a global model, shows this convergence along the lakeshore well late Sunday night into Monday:

post-525-0-50579200-1325403333.png

This should result in the convergence remaining along the lakeshore through 12z Monday. The Euro/NAM and even the NMM/ARW models do begin sagging the convergence south of the lakeshore and well into Cuyahoga/Lorain counties by 12z Monday. Buffalo’s 0z in-house WRF is slower with the process:

post-525-0-00076000-1325403359.gif

Models are generally a little too fast in dethatching a convergence band with a lakeshore. The synoptic flow will be slowly shifting more WNW as the deep low pulls off to the NE so the convergence band will eventually detach from the lakeshore, but I do think it will take until around 12z Monday for significant southerly progress to be made. This is a little slower than the NAM/Euro/NMM/ARW.

Because we won’t see an abrupt wind shift until late Monday afternoon, I expect the convergence band to remain strong for much of Monday as it slowly sags south. This will be aided by increasing lake induced instability and a continued deep and moist boundary layer. This should result in a period of moderate to heavy snow for much of the Cleveland metro south and west into Lorain county and northern Medina/Summit/Portage county. Lake Michigan moisture will likely continue feeding over Lake Erie and result in snow showers filling in well north of the convergence band as it sags south.

Behind the arctic front 850mb temps will plummet to -18C by late Monday night and winds will shift to a more NNW direction:

post-525-0-67050800-1325403424.png

This will result in extreme lake induced instability with lake-850mb delta-t’s maxing out at over 20C late Monday night. The boundary layer will also remain very moist through about 12z Tuesday.

The wind shift along the front will likely lead to another period of strong convergence moving from north to south from the lake shore early Monday evening resulting in another band of heavy snow sagging south. Behind this arctic front, the fetch will be short and any convergence bands will likely dissipate, but we will be left with very favorable lake effect conditions for the rest of Monday night:

post-525-0-51318100-1325403461.gif

When factoring lake temperatures, equilibrium levels rise to near or just over 700mb/10,000 ft and regardless, that whole layer is very moist. Winds do not align as well as they can after the arctic front, which supports disorganized bands. However, the shear instability and moisture combined with orographic lift caused by higher elevations away from the lake should result in continued moderate to heavy high ratio snow Monday night over the higher elevations inland from the lake.

One wild card is a potential Huron connection with a NNW flow. Right now I think it stays well east of greater Cleveland but could cause a period of heavy snow over the primary Snow Belt as it swings west Monday night then back east Tuesday.

Tuesday morning dry air and ridging will start moving in, causing a gradual decrease in snow starting Tuesday morning:

post-525-0-34766400-1325403529.png

Most of the snow should be done by Tuesday evening as the boundary layer will be dry and ridging will be nearly overhead.

So, in summary:

Pros:

-Extended period of moderate to extreme lake induced CAPE

-Very deep and moist boundary layer.

-Relatively well aligned winds

-Upstream lake connections (Michigan through late Monday, then potentially Huron late Monday night into Tuesday)

-Best instability will be located in the dendrite growth zone, aiding in creating high snow ratios.

-Shortwave rotating through mid event to really cool things off farther.

Cons:

-Winds will be slowly shifting essentially the whole event.

-Winds will be higher than ideal and will limit potential along the lakeshore once any convergence bands shift south by late Modnay.

Forecast accums:

post-525-0-59916100-1325403556.png

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12Z NAM for CGF:

post-7331-0-92158500-1325430010.png

Looks like the heaviest snow for Chagrin area will be from late morning Monday to just after midnight Tuesday. Winds are a bit steep but it is the NAM, so perhaps they'll be a little lower? Also, although the bands may be disorganized there will be a lot of wind speed convergence, cold air advection & moisture in the boundary layer...so a decent lake effect event should be widespread and not localized.

I'm thinking there will be a Lake Huron connection as well, but likely over Ashtabula and when the winds do veer more NNW the air begins to get very dry. I'm predicting 12-18" event total for Chagrin Falls.

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Lake Erie lake effect snowstorm 1/1-1/4:

The setup:

A large upper level trough will slow down and amplify over the northeast. A strong surface low pressure generated by the trough will move through the northern Great Lakes on Sunday and move off towards the Canadian Maritimes by Monday night. Cold high pressure—up to 1040mb—will dive south into the Plains and then slowly begin moving into the Great Lakes Monday night and Tuesday, effectively cutting off the lake effect over Lake Erie by Tuesday evening. The amplifying trough will force a shortwave south through the lower lakes Monday afternoon and evening, ushering in the coldest air of the season with 850mb temps dipping to as cold as -18C by Tuesday morning over Lake Erie.

Under the trough, deep synoptic moisture will help seed lake effect, low-mid level vorticity will remain high which will contribute to low level lift, and low level winds will be reasonably well aligned (generally 30 degrees or less of shear in the lowest 10k feet of the atmosphere).

Specifically for northern Ohio, things should start firing up around 1am Monday. The synoptic flow will initially start out WSW, which will aid in creating convergence along the eastern lakeshore. With water temperatures in the western basin hanging around +2C and at +4 east of Lorain, it will take 850mb temps of -9 to -11C to see sufficient delta T’s for true lake effect convection. We should attain this very late Sunday evening or just past midnight Sunday night:

Although the mid level flow will be WNW by this point, the synoptic low level flow will still be WSW and only slowly start gaining a more northerly component into Monday morning. The flow is a little fast, but convergence usually develops along the lakeshore due to the temperature differencial between the cold air over land and the warmer air over the lake. In addition instability will become moderate by Monday morning, the flow is well aligned, and the boundary layer is deep and very moist, as shown on the Euro above. The Euro, a global model, shows this convergence along the lakeshore well late Sunday night into Monday:

This should result in the convergence remaining along the lakeshore through 12z Monday. The Euro/NAM and even the NMM/ARW models do begin sagging the convergence south of the lakeshore and well into Cuyahoga/Lorain counties by 12z Monday. Buffalo’s 0z in-house WRF is slower with the process:

Models are generally a little too fast in dethatching a convergence band with a lakeshore. The synoptic flow will be slowly shifting more WNW as the deep low pulls off to the NE so the convergence band will eventually detach from the lakeshore, but I do think it will take until around 12z Monday for significant southerly progress to be made. This is a little slower than the NAM/Euro/NMM/ARW.

Because we won’t see an abrupt wind shift until late Monday afternoon, I expect the convergence band to remain strong for much of Monday as it slowly sags south. This will be aided by increasing lake induced instability and a continued deep and moist boundary layer. This should result in a period of moderate to heavy snow for much of the Cleveland metro south and west into Lorain county and northern Medina/Summit/Portage county. Lake Michigan moisture will likely continue feeding over Lake Erie and result in snow showers filling in well north of the convergence band as it sags south.

Behind the arctic front 850mb temps will plummet to -18C by late Monday night and winds will shift to a more NNW direction:

This will result in extreme lake induced instability with lake-850mb delta-t’s maxing out at over 20C late Monday night. The boundary layer will also remain very moist through about 12z Tuesday.

The wind shift along the front will likely lead to another period of strong convergence moving from north to south from the lake shore early Monday evening resulting in another band of heavy snow sagging south. Behind this arctic front, the fetch will be short and any convergence bands will likely dissipate, but we will be left with very favorable lake effect conditions for the rest of Monday night:

When factoring lake temperatures, equilibrium levels rise to near or just over 700mb/10,000 ft and regardless, that whole layer is very moist. Winds do not align as well as they can after the arctic front, which supports disorganized bands. However, the shear instability and moisture combined with orographic lift caused by higher elevations away from the lake should result in continued moderate to heavy high ratio snow Monday night over the higher elevations inland from the lake.

One wild card is a potential Huron connection with a NNW flow. Right now I think it stays well east of greater Cleveland but could cause a period of heavy snow over the primary Snow Belt as it swings west Monday night then back east Tuesday.

Tuesday morning dry air and ridging will start moving in, causing a gradual decrease in snow starting Tuesday morning:

Most of the snow should be done by Tuesday evening as the boundary layer will be dry and ridging will be nearly overhead.

So, in summary:

Pros:

-Extended period of moderate to extreme lake induced CAPE

-Very deep and moist boundary layer.

-Relatively well aligned winds

-Upstream lake connections (Michigan through late Monday, then potentially Huron late Monday night into Tuesday)

-Best instability will be located in the dendrite growth zone, aiding in creating high snow ratios.

-Shortwave rotating through mid event to really cool things off farther.

Cons:

-Winds will be slowly shifting essentially the whole event.

-Winds will be higher than ideal and will limit potential along the lakeshore once any convergence bands shift south by late Modnay.

Forecast accums:

Excellent write-up and forecast. Snowfall amounts are the biggest wild card IMO. A lot will depend on where and how long the convergence band sits in place. Occasionally we'll get a WSW south of the lakeshore with WNW winds across the lake that don't budge for hours... but that typically happens with slower wind speeds.

My snowfall forecast for MBY is 4-12 inches... its just impossible to tell. Inland areas should do well once winds turn - the 422 corridor. Erie should be the jackpot as they will benefit from the WSW and NW fetch.

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CLE has updated the WRF NAM. Definitely shows a Lake MI connection. I didn't realize CLE was so bullish on snow totals -

DEEPER MOISTURE PULLING EAST OF SNOWBELT AROUND 12Z TUE MORNING SOSHOULD SEE LAKE EFFECT TAPER TO SCT SHSN BY AFTERNOON SO ENDING OF

WARNING AT 4 PM STILL SEEMS REASONABLE. IN TOTAL SHOULD SEE A GOOD PART OF THE SNOWBELT GET 10 TO 24 INCHES FROM THIS EVENT.

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Wasn't expecting it to surge into the lower 50's today ...

Seems to be good consensus that an initial band of snow will slide south tomorrow around the 5-9 am time frame. I think that might be the only shot that I have at getting accumulating snow, and whatever falls will most likely blow away by nightfall.

The WRFs really haven't been pumping that much QPF for NE Ohio compared with the other lakes. Even the BUF runs, which are notoriously overdone, only has a maxima of 0.89" in Geauga.

I think it will be difficult to get accurate snowfall measurements for this event and whatever reports do come in will be wildly different based on this.

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On the plus side, I think we see some high ratios so it won't take much qpf

Your location will probably do fine.

I think OHweather's map looks great. There will definitely be some good amounts in the favored Geauga County locations, but the majority of the east side Cuyahoga suburbs will probably end up with amounts in the 6-8" range, which is nothing out of the ordinary, except for the blinding winds part ... which will be the biggest impact to this event on a day when most businesses and schools are closed anyway.

Considering this is a lake effect event, and with predicted highs in the 40's by the end of the week, I'm sure this will be a distant memory by the weekend, with just a few snow piles left in parking lots.

oh ... and I guess that YNG will receive 14.7" from this event. :lmao:

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Excellent write-up and forecast. Snowfall amounts are the biggest wild card IMO. A lot will depend on where and how long the convergence band sits in place. Occasionally we'll get a WSW south of the lakeshore with WNW winds across the lake that don't budge for hours... but that typically happens with slower wind speeds.

My snowfall forecast for MBY is 4-12 inches... its just impossible to tell. Inland areas should do well once winds turn - the 422 corridor. Erie should be the jackpot as they will benefit from the WSW and NW fetch.

Thanks. Ya, the winds shifting throughout the event will make amounts tough to pin down. Based on the lake enhanced dynamics I think we can say with decent certainty that the initial convergence band that sets up tonight and sags south tomorrow will produce heavy snows with rates possibly exceeding 1"/hr. There will likely be snow showers filling in north of the convergence band once it moves south of the lake. There will likely be another convergence band with 1"/hr type rates with the arctic front late afternoon/early evening that again will affect a good portion of the area. Behind that its a likely a matter of how close to the shore the heavy snows can fall since inland locations will likely cash in tomorrow night on the very cold but moist NW flow. Where exactly each of these heavy snow potentials produce the most is in question. If someone can cash in on all three two feet will be attainable...otherwise a solid 6"+ event is still likely inland due to the shifting winds allowing the bands to impact more areas. The shore from Lorain east will get most of its snow from the two potential convergence bands so while a 6-12" event is possible if the bands sit long enough or have very heavy snow within them, its hard to guarantee more than 3-6" along the shore and just inland.

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Meanwhile in Cleveland, people are jumping into Lake Erie on a 50°F day!

Hah. Some "polar bear" dip ... not even remotely close to forming shore ice.

It's currently 52 degrees at the lakefront ... this is no different than a morning low in June! hah

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Hah. Some "polar bear" dip ... not even remotely close to forming shore ice.

It's currently 52 degrees at the lakefront ... this is no different than a morning low in June! hah

I guess the ECMWF from the 23rd was right along (it showed a big, amplified trough) with tons of warm air advection on the east side. The GFS from the same run time: nothing, zonal.

The surface winds upstream don't seem quite as strong as predicted. About 40 knots are the strongest airport gusts I can find.

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