textproduct: Cleveland

WHAT HAS CHANGED

Confidence in advisory level snow accumulations has increased for much of the Winter Storm Watch area so have upgraded the Winter Storm Watch to a Winter Weather Advisory and expanded the headlines into Lorain, northern Ashtabula, and Crawford (PA) counties. Confidence in warning level snowfall/impacts is still too low to warrant an upgrade for Erie County, PA. There are also concerns for potential advisory snowfall amounts a tier of counties west of the Winter Weather Advisory in Ohio.

KEY MESSAGES

1) Widespread light snow expected today, but accumulations will be minimal and relatively low-impact. Heavier lake enhanced snow tonight through Monday will bring more impactful snow accumulations to the snowbelt region.

2) Multiple systems Tuesday night through Thursday will bring periodic rain and snow showers to the area with warmer weather returning by late week.

DISCUSSION

KEY MESSAGE 1... Widespread light snow showers are expected across the area today as an upper level low moves east across the Great Lakes. Generally expect snowfall totals of up to an inch, but there will likely be a swath of 2 inches or more between I-75 and I-71 prior to 00Z/7 PM. Overall, impacts should be minor through early this evening but will need to keep an eye on the area of slightly higher snow accumulations for minor impacts.

The main trough axis associated with the upper low will shift east of the area tonight, but continued upper troughing combined with strong cold air advection and wraparound moisture associated with a developing nor'easter off the Mid-Atlantic coastline will result in the development of lake-enhanced snow across northeastern Ohio and northwestern Pennsylvania tonight through Monday. Event total snowfall between tonight and Monday night (48 hours) will largely range between 2 and 5 inches across the snowbelt region of NE OH and NW PA, although locally higher amounts as high as 7 to 10 inches are possible across southern Erie County, PA. The long duration of snowfall should mitigate impacts, but still expect minor to locally moderate travel impacts. Most of the Winter Storm Watch has been upgraded to a Winter Weather Advisory, but the Winter Storm Watch remains in effect for Erie County, PA since there's greater potential for warning amounts/impacts. It's important to note that the highest snowfall totals will occur where the heaviest snow bands persist, which will likely be related to moisture connections to the upstream Great Lakes. The Winter Weather Advisory also includes Lorain County, northern Ashtabula County, and southern Crawford County (PA). The heaviest snowfall rates and greatest impacts will likely occur late tonight through early Monday afternoon and the Monday morning commute may be impacted.

There's some potential for snowfall to over-perform to the west of the advisory including Erie (OH), Huron, Richland, and Ashland counties. This area may experience more upstream lake enhancement than anticipated and snowfall totals may approach advisory amounts. Will also need to keep an eye on potential for over-performance in locations downstream from the areas of lower ice coverage on Lake Erie including Lorain, Medina, Cuyahoga, and Geauga counties. Guidance typically underestimates QPF when the lake is mostly ice covered but has appreciable areas of lower ice coverage.

KEY MESSAGE 2... Lake enhanced snow will diminish late Monday night into Tuesday. A series of systems will clip the local area Tuesday evening through Thursday, resulting in periodic rain/snow showers for the middle of the week. There will likely be another round of accumulating lake-enhanced snowfall as the first clipper moves across the area Tuesday night into early Wednesday with minor impacts possible across portions of NE OH/NW PA. There's quite a bit of uncertainty in the track of the second system and resulting precip type Wednesday night into Thursday. The GFS and ECMWF favor a more northern storm track which would support more snowfall and possibly a wintry, whereas deterministic Canadian guidance suggests a drier forecast for the area. Will need to monitor this system and adjust the forecast/communicate possible impacts as confidence increases. Dry and warmer weather will return on Friday with above normal temperatures expected late week into next weekend.

AVIATION /12Z Sunday THROUGH Thursday/

Snow and non-VFR ceilings continue across the area with an upper low moving through the region. Conditions fell to IFR for much of the area overnight but a pocket of scouring out of the lower clouds in entering NW OH may allow for some improvement to MVFR ceilings and perhaps even very brief VFR at KTOL. The next batch of potent snow and IFR is seen over western Michigan and will move in today, bringing much of the area back down to a mix of IFR and MVFR. True lake enhanced snow will flare up tonight and believe that most locations will eventually fall to IFR and northwest winds will increase across the region with some gusts in the 20-25 kt range. With time tonight, conditions will improve in the west as the snow will focus in on the traditional snow belt areas in NE OH and NW PA.

Outlook...Periodic snow with non-VFR expected through Tuesday night. Non-VFR likely on Wednesday in snow changing to rain/snow with a clipper system. Non-VFR may return again on Thursday as another system moves through the region.

MARINE

A trough remains over the eastern Great Lakes. Meanwhile, a strong low pressure system will move up the East Coast tonight into Monday, strengthening the trough over the region. Winds on the lake will be westerly to start today before becoming northwest and increasing eventually to 20 to 25 kts by Monday. This stronger northwest flow will compress ice along the Lake Erie shoreline over the next couple of days.

A high pressure ridge building into the region Monday night into Tuesday will allow for winds to decrease to around 10 kts and back to the southwest. A low pressure system will move through the Great Lakes region Tuesday night into Wednesday and southwest winds will increase over the lake. Another low pressure system will move through the Ohio Valley on Thursday and bring elevated northeast winds.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Winter Weather Advisory from 6 PM this evening to 1 AM EST Tuesday for OHZ010>014-020-021-089. PA...Winter Storm Watch from this evening through Tuesday morning for PAZ001-002. Winter Weather Advisory from 10 PM this evening to 7 AM EST Tuesday for PAZ003. MARINE...None.