OHweather

Looks like much like last week the NMM is north with the band (and has it close to last week's event) while the ARW has the heaviest along or a bit south of 322. Both models have a 1-1.5" QPF bullseye somewhere in Geauga County.

Part 2: During the day Monday I expect the band to start lifting back northeast up the shoreline as high pressure noses in ahead of the next trough and backs winds a good bit. The band could very well disorganize for a few hours Monday morning behind the trough which is again, typical, but with continued extreme instability and a long fetch, I’d still expect moderate to heavy snow showers in the primary Snowbelt, perhaps favoring the higher terrain some…they just won’t be as organized. By Monday evening the models are really increasing convergence across Ashtabula and Erie Counties as temps start dropping again inland and high pressure continues to nose into the Ohio Valley, with another trough evident to the north starting to drop down. This suggests the band should start becoming more focused again by later Monday into Monday evening. Forecast soundings from Erie for Monday evening off both the 12km NAM and 4km NAM show continued high EL’s, good moisture, fairly well aligned winds and very strong lift in the DGZ. As convergence increases Monday evening and the band re-organizes I’d expect heavy snow rates of 1-2” per hour to resume. During the day Monday it takes until about mid-afternoon for the winds over the lake to go due west, so the snow showers may affect northeast Cuyahoga, central and northern Geauga, southern Ashtabula, and at least northern Crawford County into the early to mid-afternoon before activity becomes focused farther northeast. With due west winds over the lake by Monday evening with WSW or even SW winds over land, I’d have to suspect the band will end up fairly far northeast, into perhaps northern Ashtabula and certainly into Erie County. The potential for a well-organized, stable band Monday evening appears to be decent as one last good shortwave rotates in from the north late Monday night into Tuesday morning. This should bring another surface trough south across the lake late Monday night, increase mid-level moisture some and also provide some modest synoptic lift. Most models I looked at (NAM shown above) do show a nice lobe of mid-level moisture dropping south-southeast across the lake late Monday night into early Tuesday with the shortwave. This all suggests pretty good snow rates beneath any band Monday night into Tuesday morning. Forecast soundings from Erie overnight Monday night, while not as impressive as earlier in the event, are still good, with lake to 850mb and lake to 700mb temp differentials remaining near or better than 20C and 30C respectively suggesting extreme lake induced CAPE, along with equilibrium levels remaining near 10k feet…along with good moisture to about 8k feet and some moisture to about 13k feet, well aligned winds in the low levels and good upward motion in the DGZ. Snow rates of 1 to at times 2” per hour should be attainable with that kind of profile in any well-organized band Monday night. As the trough drops south early Tuesday and starts turning the winds more NWrly over the lake while winds remain WSW or SW on land, convergence will become very strong over the Snowbelt from northern Lorain and Cuyahoga Counties points east Tuesday morning. This supports snow rates again maxing out at potentially 2-3” per hour briefly as the trough starts pushing south early Tuesday. NAM forecast profiles for CLE still look decent Tuesday morning…easily supportive of heavy snow rates given the expected strong convergence as the trough approaches and then pushes south. The trough could bring winds around to the NW enough to push the snow farther inland Tuesday morning than Monday morning…possibly getting into most of Lorain and parts of Medina/Summit/Portage for a time…before the high starts building back in and backing the winds again. Behind the trough inversions really crash on Tuesday and remain at 3-4k feet through the day. The activity should start shifting back northeast on Tuesday into the primary Snowbelt but will mainly be light by that point with just minimal additional accumulations. BUFKIT time-height profiles for CLE and ERI from the low-res NAM indicate high humidity (color fill) and good lift (red contours) in the DGZ (purple/white contours in the lower portions of the images) throughout the event…with clear bullseyes when convergence and hence banding could very well be maximized at each location. This suggests moderate to heavy snowfall in the bands through the event with many areas seeing multiple possible windows of banding. Snow ratios will probably be good due to good lift and humidity in the DGZ but not great due to the cold suppressing the height of the DGZ. As for specific amounts…expect 2-3” in the primary Snowbelt with the frontal snow through Sunday afternoon and an inch…locally a bit more elsewhere. I expect light accums Sunday evening before the band really organizes from eastern Cuyahoga County points east, especially in the higher terrain inland. Expect banding to flare up for several hours late Sunday night into Monday morning with little movement and heavy rates…think an additional 4-8” is quite possible where this banding sets up, possible near 322. NW PA will also see good snow in the orographic lift areas in this timeframe and will probably see a better band or two as well wherever upstream moisture from Lake Michigan makes it and possibly downwind of upstream bays over northern/western Lake Erie, which are often initiation points for bands. Think 5-9” in inland NW PA in this timeframe as it should snow just about all night with moderate to heavy snow for several hours after midnight. The banding should sag south briefly Monday morning and possibly drop an inch or two as far south/west as I-80. Expect the band to break up some Monday morning behind the trough and slowly push north through the day. Think maybe another 1-3” in NE Cuyahoga, Lake, northern/central Geauga, Ashtabula, Erie and northern Crawford in this timeframe, least near the lakeshore and most in the higher terrain. I'm expecting a better band to develop Monday evening near the lakeshore in Ashtabula into Erie County PA. The lakeshore in Erie County could get hit decently in this timeframe as well as winds on land really try to back. This band looks to have a several hour window of little movement and moderate to heavy snow and should produce another 4-8” where it sits Monday night, before pushing south early Tuesday. The band should persist for a couple hours or so as it pushes back southwest across northern/eastern Cuyahoga, southern Lake and Geauga and could produce a quick 2-4” or so as it goes…with lighter amounts possible again about as far south as I-80 Tuesday morning. Think another 1-2” in the primary Snowbelt (mainly in the higher terrain) from mid-Tuesday morning through Tuesday afternoon as the event winds down. Totaling things up, I get two areas where banding looks to be persistent for longest…parts of eastern Cuyahoga into northern/central Geauga…and also inland Erie County PA. Totaling things up in these areas am getting about 18-24” in parts of inland Erie County…with 12-18” in surrounding portions of Erie County, northern Crawford County and perhaps adjacent far eastern Ashtabula where there are some hills. Am also getting 10-20” in northern/possibly central Geauga County and far eastern Cuyahoga County along 322 and east of 271. Will call that 12”+ because I’m not sure they’ll get near the top end of the 10-20” range unless the band really sits in one area. There will be a couple of windows for banding along the western lakeshore west of Downtown although the banding looks more persistent farther east, so will bring moderate amounts into the western lakeshore, and put a little additional snow in for lake effect as far south/west as northern Lorain/northern Medina/northern Summit/northern Portage. The lakeshore in Lake County looks to see mainly transient banding and may struggle to see 6” or so over the course of the event. Will go a bit higher in NE Ashtabula as they could be under banding Monday night. Parts of Ashtabula may be in a bit of a whole between banding throughout the event as they often are but there will be plenty of window for snow…so I think inland Ashtabula can squeak out 8” or so over the course of 48 hours but the heaviest probably will be elsewhere.

What could be the largest lake effect snow event of the season in Northeastern Ohio is imminent as a lobe of the polar vortex brings the coldest air of winter thus far over the almost completely unfrozen waters of Lake Erie over the next couple of days. A cold front will move through NE Ohio and NW PA early to mid-afternoon on Sunday, with arctic air behind the front. This front will be passing through as a modest shot of positive vorticity advection (PVA) along with lift on the nose of a low to mid-level jet and in the left-exit quadrant of an upper level jet are all intersecting over the area as the front moves through. With forecast soundings showing nearly saturated profiles up to about 15K feet as the front goes through, certainly think this large scale lift will set off a general area of light snow late Sunday morning into the early afternoon across NE OH and NW PA. As the front moves through, forecast soundings show steep lapse rates and a little bit of CAPE into the snow growth zone (DGZ) which when combined with strong convergence/low level lift with the front itself will likely result in some snow squalls developing along the front: A forecast sounding for CLE off of the 0z 4km NAM as the front approaches shows the deep moisture (and weak lift in the mid-levels associated with the large scale lift discussed above, the white line is vertical motion, to the left is rising/upward motion), along with some CAPE to about 6k feet and through a good portion of the DGZ. This supports the notion of a general light snow for a couple or few hours with squalls along the front where low level lift will be maximized. In addition, there will already be some lake induced CAPE, so the squalls over the Snowbelt may pack a bit more of a punch along the front as the lake will add some additional instability. All in all, think the period of light snow and brief embedded squalls along the front will produce a general inch or so of snow for most of NE Ohio, with perhaps 2-3” in the primary Snowbelt in NE Ohio and NW PA where more instability will likely strengthen any snow squalls along the front. Ratios may be mediocre outside of any squalls which will likely limit over-performing potential with the synoptic snow. After the light amounts of synoptic snow, the attention will inevitably turn to lake effect snow as a very deep and cold upper low moves across the Great Lakes. There will likely be a period late Sunday afternoon and into the evening behind the frontal passage where lake effect takes some time to organize…which is fairly common…note how by 1AM Monday, the NAM is still just starting to develop better convergence across the Snowbelt. However, the above temperature/pressure pattern appears favorable for a strong, single band to eventually form from Cuyahoga County points east with NW to SE oriented isobars, a surface low pulling away to the east, some hints at a lake aggregate trough developing in the isobars, and another little trough evident in the isobars over southern Lower MI. Even if any bands struggle to consolidate some for a time Sunday evening, forecast soundings still suggest some decent moderate bursts of snow in the primary Snowbelt with W or WNW winds, moisture to 5k feet or so and equilibrium levels of near 11k feet. Forecast soundings from Erie are even gaudier with the instability Sunday evening with EQ levels near 13k feet and slightly warmer lake waters. I’d have to suspect that moderate to heavy orographic lift snows will occur in the higher terrain in inland Erie County and northern Crawford County Sunday evening even without a well-organized band due to the long fetch, extreme instability, pre-seeding and a fairly well-aligned flow. The NAM and Euro both agree on convergence really increasing across the Snowbelt after 1AM Sunday night into Monday morning as a trough drops southeast across Lake Erie while pressures rise over land and temps cool into the single digits inland. The trough dropping across the lake appears to be a result of another lobe rotating around the PV and moving across Lake Erie and northern OH/NW PA late Sunday night into Monday morning. This should provide some modest upward motion to enhance the lake effect further. In addition, this little lobe brings the coldest temps aloft, with 500mb temps bottoming out over the lake at near -40C early Monday morning. With lake to 850mb temp differentials of 22-24C…lake to 700mb differentials of 31-33C…and lake to 500mb differentials of 40-44C late Sunday night into Monday morning…along with some weak synoptic lift, a connection from Lake Michigan, and strong convergence over the Snowbelt, I have to expect a very focused and strong band to occur after midnight Sunday night into Monday morning as the trough approaches and pushes across the lake. Snow rates could briefly max out at 3” per hour under the band as the trough pushes into the lakeshore communities early Monday morning and maximizes convergence. A forecast sounding for CLE off of the 0z 4km NAM valid Monday morning as the trough is pushing through shows a deep layer of instability with high equilibrium levels and well-aligned winds. The DGZ is confined to the lowest 3-4k feet due to the very cold air, but the model shows the lowest 2-3k feet of the cloud layer being in the DGZ with the strongest upward motion also in the DGZ. So although the cold may keep ratios from getting to very high values such as 30-40:1, I think 20:1 is still very much doable Sunday night into Monday morning which will allow for relatively efficient accumulations. Forecast soundings for Erie are even more impressive, with equilibrium levels near 15k feet and around 1000 J/KG of lake induced CAPE…supportive of very heavy snow rates. As for band placement Sunday night into Monday morning…the NAM surface winds suggest it’ll be focused from extreme NE Cuyahoga east across southern Lake, northern Geauga, southern Ashtabula and into southern Erie/northern Crawford Counties. However, the isobar orientation as seen a few images up is a very close match to previous Cuyahoga County single band cases, and 850mb winds seen in the above image are in the 290-300 range over NE Ohio and the lake, which suggests winds over the lake should try to take on a pretty good northwesterly component and push the band inland a little bit. Everything suggests the band should sit 5-10 miles farther south than the band last Tuesday night sat. The 0z ARW has the band from near Avon east across most of northern and central Cuyahoga County east into Geauga County, with the heaviest just south of 322. The NMM is a bit farther north and takes the best band from Cleveland and Bratenahl ESE and is more centered right on 322. The winds backing some over land do give me pause on bringing the band too far south so I tend to think that the NMM is closer on band placement Sunday night into Monday morning as the trough approaches. Think there could be a 4-6 hour window from about 2AM-7AM (give or take an hour) where the band moves very little as the trough approaches, with the band swinging south into more of Cuyahoga and southern Geauga Counties *briefly* immediately behind the trough, before starting to slowly drift back north. There could be significant accumulations in that window where the band sits. In NW PA with a due west or WNW wind ahead of the trough, think the banding will stretch from northern Ashtabula east across inland Erie and northern Crawford for several hours, with snow rates of 1 to perhaps 2” per hour at times over the higher terrain given the very strong instability and lift with the trough. Could also see rates locally max out higher here too as the trough pushes inland and really enhances convergence for a time.

I have you getting roughly 8" on the map I was sketching up earlier but with heavier amounts to your north and lighter just to your south, so I think you'll get more than this past event but still be too far south to jackpot. I'll post my map and a write up later tonight but it may be a while until I get around to it. Hopefully this isn't the "banner" event of the season for the Ohio snowbelt.

Not a bad first forecast from CLE, although I'm personally more optimistic about parts of Cuyahoga getting warning criteria snow. I definitely think some areas will get 12-18" where the bands are more persistent.

There definitely are some similarities, especially Sunday night. At this point I'm feeling pretty good about a good band because of this, but location is obviously still up in the air. There isn't a ton of difference between a pattern favorable for a band slipping into a good portion of Cuyahoga and all of Geuaga and a setup similar to say Tuesday night of this past week so I don't want to go all in on a forecast of heavy snow for Cuyahoga and southern Geauga...but the winds do appear to be a little more favorable for it with this upcoming event than the past event. I certainly can't see any band setting up farther north than Tuesday night's band did. There appears to be at least a 12-24 hour window from Sunday evening through Monday evening where winds move very little with moderate to extreme instability and decent moisture so there could be some pretty big totals. Some models try to back the winds a bit on Monday which would shift the band north a little bit, while others don't move the winds a ton until early Tuesday...such as the Euro which drops a second trough across the lake Monday night and would extend the event. My one concern remains if the dry and cold air will limit snow ratios. The NAM and 4km NAM still show enough moisture to keep the bottom few thousand feet of the clouds in the DGZ, but the GFS remains drier with the low levels and would be dry enough to hurt snow ratios. That could honestly make the difference between a 1 to 2 foot event which I currently think is on the table for someone and a more run of the mill 4-8" event with the snow falling as a bunch of needles.

In an effort to identify scenarios that support heavy, single banded lake effect snow into Cuyahoga County, I looked at several recent warning criteria lake effect snow events in Cuyahoga County that were caused by a single band of heavy snow (not multi-banded and/or orographic lift, or lake enhanced snow). The sample size is small but potentially useful. These events were off the top of my head as I’m quickly throwing this together, I’m sure I missed some events in the late 2000s. The following are surface maps from warning criteria, single banded events in Cuyahoga County that effected a fairly large portion of the county with heavy snow events. Surface maps are from the approximate time of maximum snow intensity: (the maps came out a bit fuzzy in the post, I linked to the WPC's surface map archives for the appropriate day for each event, those maps are less fuzzy) April 7th, 2007: Link to surface maps from this date for you to scroll through as you please: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=04/07/2007&selmap=2007040712&maptype=namussfc This was a part of a long duration, significant and out of season event. A heavy band of snow developed from the northwest portions of Cuyahoga County and set up east or slightly south of east towards the southeast portion of the county towards Solon and Chagrin Falls. Amounts from the band were in the 6-10″ range. The isobars over Lake Erie and Northeast Ohio are roughly oriented NW to SE, with a clear surface trough evident over central lower Michigan dropping south or southeast. There is a surface low over south-central Quebec and a surface high extending from western Manitoba south across the central Plains. April 8th, 2007: Link to maps from this date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=04/08/2007&selmap=2007040812&maptype=namussfc This was a part of the same event described above, just a day later. A band of heavy snow redeveloped on the evening of the 7th into the morning of the 8th, a few miles farther north than the previous night. The band set up from near downtown Cleveland east towards east-central Cuyahoga County, with heaviest amounts near or just south of the 322 corridor in eastern Cuyahoga County. Amounts with the band were up to a foot on the east side. The isobars are oriented a little more WNW to ESE, with a stronger surface low near the northern tip of Nova Scotia and the surface high slightly farther east extending from central Manitoba south across the Plains. A clear surface trough is evident across central lower Michigan. December 8th, 2010: Link to maps from this date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=12/08/2010&selmap=2010120821&maptype=namussfc Anyone who lived in Cleveland into December of 2010 should remember this event. A band of heavy snow developed across northern and eastern Cuyahoga County during the morning on December 8th and intensified during the afternoon while remaining nearly stationary. The heaviest snow affect the western lakeshore and downtown Cleveland (with over 10” of snow near downtown) and extended east into much of eastern Cuyahoga County, with even Solon receiving warning criteria snowfall. The band shifted south and weakened during the evening of the 8th. This came at the end of a significant, multi-day lake effect event. The isobars are roughly oriented northwest to southeast, with a clear trough near or just north of Lake Erie. There is a surface low located east of Hudson Bay and a surface high extended from near the Ontario/Manitoba border south across the Mississippi Valley. A nose of higher pressure extends east across the Ohio Valley as well. January 2nd, 2012: Link to maps from this date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=01/02/2012&selmap=2012010212&maptype=namussfc This occurred at the beginning of a warning criteria (but not incredibly notable) lake effect event for the primary Northeast Ohio Snowbelt. A snow band developed across the eastern lakeshore in Lake and Ashtabula Counties overnight on the 1st into the 2nd and shifted into eastern Cuyahoga County on the morning of the 2nd and persisted for a few hours, before shifting south and dissipating. Warning criteria snow occurred during a 12 hour period during the daylight hours on the 2nd in portions of east-central Cuyahoga County. This is a marginal case. The isobars are oriented roughly northwest to southeast, with a surface low located southeast of Hudson Bay. High pressure extended from central Manitoba south-southwest towards central Texas. A surface trough is evident over northern lower MI and central Lake Huron and is analyzed as a cold front on this map. January 22nd, 2013: Link to maps from this date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=01/22/2013&selmap=2013012218&maptype=namussfc This was a part of a fairly decent multi-day event in the primary Snowbelt mainly east of Cleveland. A single band of snow developed across northern and eastern Cuyahoga County late in the evening on the 21st and persisted into the morning on the 22nd, before shifting south and weakening by late morning on the 22nd. The heaviest snow occurred from the lakeshore in Cleveland east towards the eastern suburbs such as Lyndhurst and Mayfield. Amounts from the band were over 6″. The isobars are roughly oriented northwest to southeast, with a clear surface trough analyzed as a stationary front extending across northern Michigan and Lake Huron. A smaller surface trough is analyzed in southeast Michigan but has a minimal impression on the pressure field. A surface low is located off the New England coast, with high pressure extending from North Dakota south-southeast towards Illinois and Arkansas. A nose of higher pressure extends east through the Ohio Valley. October 24th, 2013: Maps from the date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=10/24/2013&selmap=2013102412&maptype=namussfc This was one of the most significant October lake effect snow events that Northeast Ohio has seen in recent memory. A snow band developed in the evening of the 23rd, initially across northern and eastern Cuyahoga County east into Geauga County, before shifting north into Lake, northern Geauga, and Ashtabula Counties for a few hours. The band settled back south into northeastern Cuyahoga County early in the morning on the 24th and was persistent through most of the afternoon from over or just north of downtown Cleveland east towards Mayfield, at times getting as far south as Beachwood, but generally a little farther north. Snowfall amounts of near 8” occurred in Mayfield Heights. If this occurred when it was colder, snowfall totals of 1 to 2 feet very well could’ve occurred on a fairly widespread basis. The band shifted south and weakened during the evening on the 24th. The isobars were generally oriented WNW to ESE…however, a very well-defined trough moving across the lake had a strong impression on the pressure field downwind of the trough in Northeast Ohio. A low was located east of Hudson Bay with a high extending from southeast Alberta towards Kansas. A small area of higher pressure extended east through the Ohio Valley. November 14th, 2014: Maps from the date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=11/14/2014&selmap=2014111412&maptype=namussfc This was a part of a multi-day event focused from northern Lorain County points east. A strong band of heavy snow developed along the eastern shoreline from Lake County up through Erie County PA on the 13th, with some areas receiving over a foot of snow during the day on the 13th. That first single band swung southwest during the evening and produced a quick couple inches or more of snow as it went as far west as parts of central Lorain County, before the band broke up and multi-bands took over for a time. A single band re-organized early in the morning on the 14th from northern Lorain County east across a large portion of Cuyahoga County and southern Geauga County and persisted for several hours, before becoming more diffuse in the evening on the 14th. The second band allowed portions of eastern Cuyahoga County to reach the 24 hour warning criteria of 8” or more of snow. The isobars were oriented northwest to southeast, with a modest surface trough evident from central Lake Huron points west. A surface low was located well off the New England coast, with a surface high across the eastern Plains. Higher pressures extended east through a good portion of the Ohio Valley. November 20-21st, 2014: Maps from the data: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=11/21/2014&selmap=2014112106&maptype=namussfc This event came at the end of a multi-day event that dropped feet of snow on western New York south of Buffalo. A well-established single band pushed southwest across the lake late in the afternoon and into the evening on the 20th and swung through Cuyahoga County fairly quickly, before stabilizing for several hours from northwestern Lorain County east-southeast into southwestern Cuyahoga County, just south of the airport. Snow totals of up to 6” occurred in parts of southwestern Cuyahoga County. The band quickly broke up on the morning of the 21st as high pressure moved in lowering inversion heights and as winds turned more northwesterly. The isobars when the band stabilized across parts of Cuyahoga County were oriented NW to SE, with a clear trough near the south shore of Lake Erie and another one farther northwest across central lower Michigan and Lake Huron. A surface low was located north of Maine and a surface high stretched from Iowa to Kentucky. November 27th, 2014: Maps from this date: http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=11/28/2014&selmap=2014112800&maptype=namussfc This was a short duration, high intensity event. The event started early in the morning on the 27th as a surface low moved up the East Coast and swung the winds around from NE to NW. Multi-banded lake effect with some Lake Huron connection developed into the west side early in the morning and quickly swung east across the Cleveland metro into the primary Snowbelt and dissipated by late morning. 1-2” of snowfall fell in parts of the metro with this portion of the event. The snow essentially ended for several hours before a surface trough dropped across the lake during the evening and produced a single band of heavy snow into northern Lorain, southern and eastern Cuyahoga, far northern Summit, southern Geauga and northern Portage Counties for a few hours, before the trough shifted south causing the band to shift south and break up. Snowfall rates of 3” per hour were observed at CLE and some areas received 6” of snowfall in under 3 hours, making this a warning criteria snowfall. A surface low during the time of the band was located northeast of Nova Scotia, with a surface high extending from Iowa to Mississippi. A surface trough was located over Lake Erie when the band occurred. Isobars were located north to south north of the trough and NW to SE south of the trough. Summary: Every event featured isobars oriented a pretty true NW to SE. A couple of events had isobars slightly more westerly than northerly, but were generally oriented NW to SE or very close to it. Every event featured lower pressure somewhere to the east or northeast, with an inverted trough extending back towards the Great Lakes. Most of the events that locked a band in for more than a few hours also had high pressure extending east from the central US into the Ohio Valley…events like 11/27/14 and 1/2/12 that were more marginal and didn’t feature a well-organized band for more than a few hours didn’t have higher pressure nosing into the Ohio Valley as well as the other events did. Every event had at least a subtle surface trough over Lake Erie or not far to the north. It seems that for a single band of lake effect snow to produce warning criteria snow into a good portion of Cuyahoga County, a few things are needed (other than the obvious proper moisture/instability for a strong lake response): -Low pressure to the east or northeast with an inverted trough extending towards the Great Lakes. The inverted trough doesn’t seem to be required as a couple of good events didn’t have it, but most events do have a feature like that. -At least a subtle surface trough over the lake or just to the north of the lake. An inverted trough extending west from a surface low to our east or northeast can serve this purpose. -Isobars oriented northwest to southeast. More WNW to ESE isobars may still clip the extreme NE corner of the county but would likely miss a majority of the county. -High pressure nosing into the Ohio Valley appears to make it more likely for bands to lock into place for more than a brief period of time. -High pressure placement to our west doesn’t seem extremely important, as long as the high is centered to the west somewhere with preferably some higher pressure extending east into the Ohio Valley. Shortfalls: Obviously this is a small sample size off the top of my head. There is the possibility that other seemingly favorable environments with similar pressure patterns didn’t produce, so this doesn’t scratch the false alarm rate of using isobaric patterns to predict if a single band of lake effect snow will occur in Cuyahoga County or not. Only warning criteria events were used…shorter duration events that only produced advisory snowfall were not explored as again, this sample was off the top of my head. More obviously goes into lake effect forecasting than the isobaric pattern, however, all 9 events featured very similar patterns so I believe this information can still be useful.

I actually remember that event, albeit vaguely. That event kicked off what went on to be a very memorable winter across the region (CLE had their snowiest winter by far that winter). Looking into Lake Huron enhanced events will be harder because we haven't had many good ones recently and they're generally less common...but they do still happen and can produce big totals, so when I get time I'll try to look into them. It may not be in the immediate future though. I'll post my quick "research" into Cuyahoga County heavy single bands shortly...

Thanks for the kind words ^ As for the upcoming events...there could be some lake effect/enhanced precip on Saturday. The lowest 4k feet are moist and unstable enough for lake effect with a W or WNW flow...but there's an inversion near 4k feet on Saturday with moisture struggling to get into the snow growth zone, so any lake effect would be light and could possibly mix with freezing drizzle. Better threat obviously Sunday-Monday as our friend the polar vortex moves right across the Great Lakes. Could be a shot of light synoptic snow on Sunday on the leading edge of the arctic air before lake effect sets up Sunday night. Some pros and cons to this event although early on I'm leaning towards some areas getting warning-worthy amounts. Pros are not much wind shear and a well aligned WNW flow along with what should be plenty of instability and high inversion heights. Cons are the inherently dry nature of arctic airmasses...although, a long fetch off of Lake Erie and possibly some pre-conditioning from Lake Michigan could alleviate that concern...something to watch. Other con is once 850mb temps start getting to -20 or -22C the snow growth zone is often below or only in the lower portions of the cloud, meaning snow ratios can struggle. The 0z NAM shows 850mb temps of more like -18C or -19C Sunday night with good moisture in the snow growth zone thanks to pre-conditioning from Lake Michigan...the 0z GFS is a little colder with 850mb temps and drier in the low levels. The NAM tends to pick up on lake modification better, but I want to see it hold with the idea of enough moisture for high ratios as we get closer. As for possible banding...models are showing a nice surface trough dropping southeast towards Lake Erie Sunday night which tends to favor a good single band developing, before the trough pushes southeast on Monday. Some convergence would likely persist in the Snowbelt on Monday as pressures rise over land. This all suggests that decent banding may be around for much of the event. As for possible band placement...winds on the GFS and NAM are WNW Sunday night into Monday before the GFS turns winds more W on Monday. I've been doing a little digging into isobar patterns that occur with strong single bands that produce warning criteria snow somewhere in Cuyahoga County (other than just in Euclid) and the isobars on the models look close to this pattern on Sunday night...the pattern for most of the great single band Cuyahoga County events are isobars oriented NW to SE with a surface trough over or north of the lake. I'll try to post more on this during the day Friday when I get more time...but it's possible banding gets into a good chunk of Cuyahoga County Sunday night (and inherently most of Geauga too) before shifting back northeast some on Monday if the models hold. If ratios struggle then amounts of say a foot or more would be hard to come by, but if we get good banding could still see some 6"+ amounts, even if the snow has the consistency of powdered sugar as it falls.

After a nice chunk of my life, here's my best guess verification map for the past event, clipper and LES included: A few notes on the map itself: -There were few spotter reports in eastern Ashtabula County and western inland Erie County that were "reliable"...I say this because there were a few spotters that called in for parts of the event but didn't for others when I knew they got snow. The only good reports in that area were MAIDEsNow's 14" report from NW Edinboro and a spotter that had a total of 13" just NW of Edinboro as well, along with 11" from a spotter near Pierpont. Radar overshoots LES badly in Ashtabula/Erie/Crawford so unfortunately I had to do a lot of guessing there based on terrain, surrounding reports and what radar happened to picked up there. -The only good reports in eastern Cuyahoga County and western Geauga County were a total of 8.8" in Euclid from a trained spotter...11" 2.5 miles north of 322 from LakeEffect in Chesterland, and 4" in Newbury/South Russell from dta and NEOH. Luckily radar doesn't overshot LES there so I feel much better about that area, but the lack of reports and sharp cutoff mean I may be a little off. The 8" edge looks jagged in NE Cuyahoga, however, that is supported by radar, as there was a good period where the band absolutely ripped on Euclid but areas immediately southwest weren't getting good snow, and a period of time earlier on in the evening when the band was farther south where heavier returns were consistently just east of 271. It's probably not perfect and a few of you live/work in/drive around in that area, so if that looks off please let me know and I can tweak. As for the forecast, was a little low on max amounts. The band placement in NE Ohio was pretty good compared to forecast, however what I needed to do was extend heavier amounts much closer to lakeshore. It seems like these firehose bands driven by strong convergence are the one type of event that do well all the way down to the shore, so it's something to keep in mind going forward. That was the biggest thing on my map that I ended up not liking. I did pretty good in Erie County PA but worse in Crawford PA. I'm trying to get better in that area, but I haven't been able to watch events there on radar for years and years because radar overshoots LES there, so it's still a process. Next event could be interesting, so on to that one.

This next setup looks like it could be a good one as well. Hopefully the "warmth" and wind/rain can keep ice from expanding anymore in the western basin later this week, a good chuck of it between Toledo and Port Clinton on satellite today.

Nice!

Best band of the year into NE Ohio by far. I suspect northern Geauga and western Lake County got another 6-10" of lake effect and have storm totals of over a foot. Band still going strong but has shifted to mainly north of route 6. I have to suspect places near Euclid got at least 6" of LES this evening and parts of Lake County from Willoughby Hills east got closer to 10" of LES so I don't understand why an advisory wasn't issued for Cuyahoga and a warning wasn't issued for Lake. Unfortunately this missed most of you guys just to the north, although I suspect Maidensnow will get a nice total. As I pointed out earlier I haven't agreed with CLE's handling thus far and I can't explain their lack of action tonight despite heavy snow rates and an organized band sitting in one area. Anyways next chance comes Sunday into Monday as the PV visits the region. Southerly winds, warmth and rain later this week should minimize ice on the western basin although I suspect the next blast of cold will really start freezing it over more. Winds look WNW for at least a time Sunday or Monday now and even if the lake cools a few degrees and if the western basin is slushy the instability could be extreme.

So far I'm liking my forecast WRT band placement...think a few spots could exceed 10" total though and places like Euclid in NE Cuyahoga will likely exceed my forecast by a reasonable amount. I haven't looked at much for several hours but the strongest push of NW winds was modeled to come around 11pm or so, so it's possible the band nudges south a bit into more of Cuyahoga and southern Geauga before shifting back northeast. Think peak band intensity will occur in that same timeframe as well...could see it produce 2-3" per hour briefly. I have no idea why Geauga isn't under a warning or why Cuy isn't under an advisory for the northern part of the county.

Every 0z WRF run I've looked at including BUF's have half an inch to an inch of QPF somewhere over Geauga County...but there's disagreement where in the county that occurs. I'm starting to feel better about parts of northern and especially eastern Cuyahoga getting a few inches of LES on top of any synoptic snow. We'll see how things are going in the morning. I suspect before all is said and done CLE will bump Geauga up to a warning and Cuyahoga will at least get a LES advisory.

I am slightly worried/intrigued about the southwestern edge of things. The rising pressure/cold air/WSW winds on land will do all they can to keep the band pretty for north, but there's a pretty decent push of NW winds for a few hours over the lake mainly tomorrow evening that will try to push the band south.

The criteria is normally 4-6" in 12 hours or less or 6-8" in 12-24 hours of snow, with no specific other criteria for winter weather advisories issued for snow. Normally CLE follows that exactly as you mentioned. In this case...every office around CLE issued advisories and completely boxed in CLE...so I suspect this advisory was mainly issued for coordination purposes. In the short but oh-so-sweet AFD CLE mentioned that they issued the advisory due to the period of best snow being near the AM commute with gusty winds adding to the issues, making it sound like they issued this as an "impact based" type advisory. CLE normally does not do this and in many cases has not issued advisories when they're clearly needed because the snow amounts are expected to be something like half an inch below criteria, which I personally think is ridiculous. So I'm not complaining about this advisory, but I'd like to see them use common sense like this more often. I can think of a couple times last winter where 1" per hour snow rates occurred during a commute with no advisory. Then there's the ridiculous Valentine's Day fiasco too which was on a weekend but featured (well advertised) severe conditions with no advisory until after more than half the snow fell.

In today's version of "he's bound to get a forecast right eventually", we have my map I haven't had time to put together a write-up yet and may make a few tweaks when I get around to that later, but general thinking is 1-2" of synoptic snow. There's a period of weak to moderate lift late tonight and Tuesday morning for several hours that should produce light snow. There appears to be a decent potential for a brief snow squall along the arctic front Tuesday morning. Between all of this think everyone should ring out 1-2" of synoptic snow. A little concerned that with the lift focused in the snow growth zone that high ratios may allow the snow ahead of the arctic front to over-perform a bit which could push a few areas over 2" so I went 1-2" with locally up to 3" for the synoptic snow area wide. For the LES portion of the event winds become aligned out of the WSW by late Tuesday morning behind the arctic front which should allow a strong single band to form over the lake and head towards SW NY initially. Winds slowly go WNW by Tuesday evening which should push the band onshore in the primary Snowbelt. Moderate to extreme instability, high inversion heights and good moisture including a fetch from Lake Michigan support heavy snow rates in the band. Winds over the lake go WNW or even NW briefly Tuesday evening which will try to push the band into parts of northern and eastern Cuyahoga County, but high pressure and cooling temps overland will try to keep the band closer to the shore. The winds should start pushing the band back northeast up the shore late Tuesday night into Wednesday morning. BUFKIT shows strong lift in the snow growth zone Tuesday night into Wednesday in the LES (a "cross-hair signature" as BUF frequently calls it) suggesting heavy snow in the band and what should be good convergence over the Snowbelt supports a good band...so amounts of 6-10" should easily be doable where the band is most persistent. Right now I have this over northern Geauga as the winds over land will try to keep the band a little farther north than so models try to take it. Erie County and SW NY will also do well. Cuyahoga County has high bust potential either way as WNW or NW winds over water will try to push the band into the county, so I did put more in northern and eastern Cuyahoga to account for this but it could be higher if the banding can firmly settle into there. If winds on land as too SW the banding may largely stay NE of Cuyahoga County so as I said...bust potential either way. Will try to have a little more later.

It looks better than this past event, the winds do go WNW for a while tomorrow evening into the wee hours of Wednesday. The potential seems to be there for a mega band in that timeframe but I'm not sure where or how intense it will be yet.CLE only issuing a watch for Erie County PA was surprising and their AFD wasn't very helpful.

It looks like northern Geauga got 4-5" totals based on the reports this morning, the bands got going kind of late and by that point everything was shifting north pretty quickly. This one wasn't a bad bust but it certainly didn't reach its potential. CLE...managed to squeak out 1.3"...the streak is over

Still waiting to see how much synoptic snow fell...seems like most areas got an inch or two. The lake effect is kicking in with some moderate bursts of snow across a lot of the area and definitely some Lake Michigan moisture...convergence is pretty weak so there isn't a good band, just moderate bursts of snow at this point. That should improve later when the winds on land start going more WSW, but when that happens the LES will probably shift into eastern Lake/northern Ashtabula/Erie Counties. We'll see what the totals end up being.

So far only 0.5", although that may just be through 18z. I'd be shocked if they didn't pick up an inch given three hours of moderate or heavy snow and temps below freezing.

Here's what I have: Discussion: A strengthening area of low pressure located just west of Cincinnati as of midnight will track northeast likely just south and east of Cleveland on Sunday while intensifying. There is currently a narrow zone of some deformation snow on the back side, with the cold air just catching the back end of the precip. This band of snow has a history of generally producing 1-2” snow amounts with locally a little more across parts of southern IL and western KY. As the low pressure deepens and as the upper level vort max associated with the sub-tropical jet shortwave fueling the system moves right over eastern Ohio, the deformation snows should maintain and perhaps intensify slightly as the system moves northeast across Ohio. The models appear to be in good agreement in tracking the best deformation from southwestern Ohio NNE towards the central lakeshore. The 700mb and 500mb vertical velocity plots also support this notion, with the best upward motion in that general corridor: By 1PM, safely after the rain/snow changeover for even eastern Ohio, note how the upward motion associated with the deform zone is starting to pull away to the northeast, mainly affecting the central and eastern lakeshore: The idea here is similar to what is happening to our southwest currently, there will be enough mid-upper level support for a brief period of moderate or even briefly heavy snow right around the changeover, however the support for better snow will be fleeting. With this said, the models are spitting out QPF of around 0.10-0.15” per hour for an hour or two after the rain/snow changeover for most areas in north-central and near the lake in northeast Ohio which jives with a brief period of decent snow. The majority of modelling appears to be in general agreement on about 0.20”-0.30” of QPF falling after the change to snow in the corridor from SW to north-central and the east lakeshore on Sunday. The duration of good snows and adjusting ratios to account for some initial melting due to the wet ground suggests that amounts may be more like 1-2” in this corridor…maybe locally more if there’s some locally better mesoscale banding, especially across the central highlands where the better elevation may allow for a somewhat quicker changeover. A forecast sounding from the 0z NAM for CLE is interesting. It shows the moderate lift in the mid-levels (the white line is vertical motion, to the left of the middle is upward motion) with the synoptic deformation zone, and also increasing instability in the lowest few thousand feet along with strong NW winds on the low levels and good upward motion in the low levels as well. This suggests that increasing low level instability and upslope may allow for lake enhancement to the snow Sunday afternoon for a time in mainly the upslope areas. This could allow for 2-3” amounts to fall on Sunday in the Snowbelt, especially in the higher terrain. The better moisture above 700mb starts stripping away around 4PM per forecast soundings, which would likely signify an end to the wrap around and good lake enhanced snow. This gives about a 4 hour window in the Snowbelt with the changeover around noon give or take an hour, so even with a potential period of rates near 1” per hour I have trouble seeing anyone getting more than 3” in the Snowbelt of wrap around snow during the day on Sunday. By Sunday evening the flow becomes well aligned from initially the west-northwest with low level instability increasing over the lake as 850mb temps drop to near -18C. We’re on the edge of the upper level trough so the depth of the moisture and instability is marginal, with moisture to near 5k feet and equilibrium levels to around 7-8k feet at CLE. Convergence should increase over the Snowbelt as high pressure builds in over land and slowly shifts the winds over land to the WSW, which will support a band. Moisture depth and instability support moderate snowfall with good ratios (good instability through the snow growth zone) Sunday evening in NE Ohio should convergence be strong enough for a band to develop. There also is good support (via 850mb RH/streamlines above) for moisture from Lake Michigan to help pre-seed Lake Erie through Sunday night. This may make up for the somewhat shallow moisture/instability and allow any bands that become mature to lift moisture and instability to higher levels. After midnight Sunday night the winds on land become WSW with west winds over water. This tends to push the convergence and better banding into eastern Lake County, northern Ashtabula County and into Erie County. The models show the winds moving very little with persistent strong convergence in this corridor for several hours Sunday night into Monday morning before the winds turn more SW and start pushing the band completely over the lake Monday afternoon and towards SW NY. Forecast soundings for ERI are decently impressive Sunday night into Monday morning with little wind shear…moderate instability extending up to 10-11k feet…moisture to above 5k feet…good vertical motion in the snow growth zone…and likely strong low level convergence in this area. This supports moderate to briefly heavy snow with ratios of 20-30:1, which is typical for LES with cold (but not too frigid) temperatures. With the banding potentially lasting several hours in a similar area late Sunday night into Monday morning with good ratios, and rates of 1 to possibly 2” per hour at times, the potential certainly exists for a significant accumulation where this banding occurs. The snow should completely end or be just reduced to some flurries in all of NE Ohio and NW PA by Monday afternoon as we then await the arrival of the clipper and LES behind that. As for snow amounts and placement… Have 1-2” for most of the area except for SE of a roughly Millersburg to Youngstown line, where the deform will be weaker leading to a period of mainly light snow with accumulations less than an inch. In the 1-2” area, a period of decent lift in the deform band should result in a brief period of moderate to briefly heavy snow and a quick 1-2”…locally more in the central highlands if a quicker changeover occurs. With lake enhancement occurring…brought 2-4” totals as far west as parts of Lorain/Medina Counties…although most areas will see mainly 2-3” here. Expect similar totals with the deform snow/lake enhancement on Sunday in parts of Cuyahoga, northern Summit, Lake, Geauga, northern Portage and Ashtabula Counties…maybe 1-2” of wrap around snow in NW PA as the best lift may only clip that area during the synoptic snow. As for the lake effect portion Sunday evening through Monday morning…initially the lake effect could clip Cuyahoga County and southern Geauga County early in the evening as winds shift from NW to more WNW. Good snow ratios along with moderate instability but marginal moisture depth combined with a long fetch, some lake Michigan moisture and increasing low level convergence suggests moderate snow will be possible. I expect the snow in Cuyahoga County and southern Geauga County (along with perhaps adjacent NE Summit/northern Portage/Trumbull Counties) to be short lived and maybe produce another inch. The band will likely start becoming more focused in extreme NE Cuyahoga, western Lake and the northern half of Geauga into Ashtabula and Crawford Counties by mid to late evening as convergence increases and the fetch increases as the winds start going more due west. The lake effect in these areas will last a few hours and add maybe 1 to locally 3” of additional snow given the expected rates (half an inch to briefly an inch an hour) and duration of lake effect in these areas. In eastern Lake…northern Ashtabula…Erie…and perhaps far northern Crawford Counties there may be some snow shower activity in the evening given a long fetch and good instability, along with terrain in Erie and northern Crawford Counties, but the convergence should initially set up south of these areas, leading to mainly light additional amounts in the evening. By midnight or so the convergence should shift north into these areas as winds overland become WSW and winds over water are west. The convergence will be persistent in these areas for a good 6-10 hours so I expect banding into these areas for over 6 hours that doesn’t move too much after midnight Sunday night through a good portion of Monday morning. Moderate instability, marginal to decent moisture depth, equilibrium levels near 10k feet, steep lapse rates and good vertical motion in the snow growth zone suggesting efficient snow ratios and strong convergence suggest snow rates will be moderate to heavy in any banding in this timeframe, with rates of 1” per hour likely and brief rates near 2” per hour possible early Monday morning in Erie County when instability and convergence appear to reach their peak. Well established lake effect bands often have better moisture depth and instability than modelled due to persistent upward motion modifying the environment on a small scale which also suggests heavy rates are possible. This suggests additional lake effect accumulations of 4-8” from northeastern Lake County east into northern Ashtabula County and a good portion of Erie County. This is assuming the band will move a little bit and keep one area from getting drilled with 2” per hour rates for several hours. It isn’t impossible if the band stalls that local lake effect accumulations of 10” or so occur, most likely in Erie County. With pretty strong westerly winds persisting over water I suspect inland Erie County will do better than the lakeshore with convergence likely staying a little bit inland. This all gives storm total accumulations of 1-2” for most of north-central and northeastern OH…with locally a bit more in the central highlands near Mansfield and Mount Vernon, 2-3” in parts of Lorain/Medina/western Cuyahoga/northern Summit/northern Portage/northern Trumbull, 3-4” in eastern Cuyahoga, southern Geauga and southern Ashtabula into southern Crawford, 4-6” in most of Lake, northern Geauga, central Ashtabula and northern Crawford, and 6-10” in far eastern Lake, northern Ashtabula and inland Erie Counties. Local storm total accumulations of up to a foot are possible in Erie County if the lake effect band is slow enough moving.

Between the wrap around and LES I'm thinking 2-4" southern Geauga County and 3-6" northern Geauga by Monday morning. We'll see if I can get around to mapping it later tonight