National Weather Service United States Department of Commerce


      On Saturday, November 28th, an upper level closed low moved out of the Four Corners Region across the southern Plains. This upper low began to open on Sunday, November 29th as it moved northeast towards the Ohio Valley, phasing with a stronger upper level trough that was digging across the Midwest. Upper level jet energy would extend all the way to the southeastern states as this upper level closed low developed over Indiana, which deepened as it pivoted towards the eastern Great Lakes on Tuesday. Meanwhile, the associated surface low pressure system originated near the Gulf Coast, tracking northeast towards Pennsylvania by 18Z Monday then continued north to Upstate New York by 06Z Tuesday. This is where the low remained for the next 12 hours, slightly retrograding westward to Lake Ontario, before finally drifting north into Quebec Tuesday afternoon.

      As the surface low tracked northeast towards Pennsylvania on Monday, widespread rain overspread the area, transitioning to snow from west to east on Monday and Monday night as cold air advected in from the west. The TRough of Warm Air ALoft (TROWAL) wrapped all the way around the low, providing lift and deep moisture to our region, with that moisture being advected all the way over from the Atlantic Ocean.

      Lower snow-to-liquid (SLR) ratios observed during this event were around 8-9:1, which is quite a bit lower than climatological values for the Cleveland forecast area, which is closer to 13-15:1. There are a few reasons this occurred. A considerable amount of the lift was located between 750mb and 900mb, which was located just below the dendritic growth zone (which was between 600 and 700 mb). Surface winds were also fairly strong, with gusts persistently around 25-30 mph (which can reduce SLR). Additionally, surface temperatures hovered in the low 30s and occasionally in the upper 20s through the duration of the event. It is likely that these factors contributed to the lower snow ratios that were observed during the event.

      Minimal snow accumulations occurred through the day on Monday as the rain snow line shifted east to the Central Highlands. A very gradual transition to snow occurred through the evening hours on Monday with Cleveland changing over around 10 PM EST and Erie at 3 AM EST. The end result was widespread snowfall of 12 to 18 inches along the primary and secondary snowbelts, extending all the way west from Lorain, OH, east across the Cleveland metro area and into extreme Northeast Ohio and Northwest Pennsylvania. Locally higher snow amounts of 18 to 24+ inches fell in eastern Cuyahoga, southern Lake, northern Geauga, western Ashtabula and inland Erie, PA counties.

      An underrated impact from this event was snow load damage to wires and trees, causing widespread power outages. At its peak, there were over 90,000 power outages on Tuesday across the NWS Cleveland forecast area, the vast majority of which was in Cuyahoga, Lake, Geauga, and Ashtabula counties. The rain that occurred on Monday froze on trees and wires after temperatures decreased Monday night and significant low SLR snow efficiently accumulated on trees and wires, causing the weight of snow to overload trees and wires across the region.

72-hour interpolated snowfall map (storm total snow) from NOHRSC, incorporating local snowfall observations.



True color satellite loop with mean sea level pressure (yellow contours) and temperature (red contours) overlaid.

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