Marine Weather and Tide Forecast for Rocky River, OH

NEAR TERM /THROUGH SATURDAY/
Aloft, a weak shortwave trough approaching from the Upper Great Lakes will sweep SE'ward across the Lake Erie region and Upper OH Valley late this afternoon through evening. Behind the trough, a shortwave ridge will traverse our region generally from west to east this evening through daybreak Saturday morning. At the surface, a ridge continues to impact our region as the ridge axis moves from near the Upper MS Valley toward northeastern NY and the central Appalachians by daybreak Saturday. This weather pattern evolution at the surface and aloft will allow low-level WAA to strengthen slowly amidst partly to mostly cloudy sky. This afternoon's highs are expected to reach the mid teens to lower 20's in NW PA and the upper teens to lower 20's in northern OH. Tonight's lows are expected to reach mainly the 5F to 15F range around midnight before readings moderate slightly by daybreak Saturday.

Primarily fair weather is expected through daybreak Saturday as a lowering and stabilizing subsidence inversion accompanies the ridge at the surface and aloft. However, as 850 mb temperatures moderate from near -18C to -16C over/downwind of ~0C Lake Erie, pockets of ice-free waters persist, and lake- induced equilibrium levels lower from near 7kft to near 3kft above the lake in response to the lowering subsidence inversion and synoptic low-level dry air advection, periodic light lake- effect snow (LES) showers are possible over/downwind of Lake Erie. These LES showers remain possible in/near portions of our snowbelt counties in NE OH and NW PA through this early evening as mean low-level flow backs from WNW'erly toward SW'erly, which will cause lake-effect stratocumuli and any associated snow to shift N'ward and E'ward with time. Any fresh LES accumulations are expected to be one inch or less in our CWA

On Saturday, the ridge at the surface and aloft exits E'ward as a surface trough overspreads our region from the Upper Midwest and western Great Lakes, and the parent shortwave trough approaches from the north-central United States and vicinity.
This weather pattern evolution will allow low-level WAA to persist in our CWA Afternoon highs are expected to reach the mid 20's to lower 30's in NW PA and the upper 20's to lower 30's in northern OH. Moist isentropic ascent ahead of the shortwave trough axis should allow periods of snow to traverse our region generally from west to east between roughly daybreak and nightfall. This snow will primarily be light, but some model sounding data indicate moderately-strong isentropic ascent may be maximized at a cloud temperature of ~-11C at times and yield brief bursts of moderate snow. Fresh snow accumulations of a coating to two inches are expected on Saturday. Note: Based on our latest air temperature and wind forecast, minimum wind chills are expected to be near 0F to -5F this morning and Saturday morning.

SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/
A shortwave will be traversing the Great Lakes Saturday night into Sunday ahead of a surface cold front that will move through. There will be some on going lake effect snow showers across the primary snowbelt as the flow will be generally out of the west through the beginning of the weekend. The early morning hours on Sunday will have the highest chance for the lake effect snow showers before drier air moves into the low to mid levels as the 925mb ridge pushes across the Ohio Valley. Snow totals will be fairly low, even with the frontal passage as most of the area will be lacking the necessary moisture. Most of the snowbelt should see around 1-3 inches in accumulation with higher totals in NW PA and in the higher elevations. The aforementioned ridge and associated surface high pressure will move into the region during the day on Sunday ending the chance of snow showers by that evening. High pressure will remain across the mid Missouri Valley and Tennessee Valley on Monday keeping the area dry for most of the day. A low pressure system moving into the southern portion of the Hudson Bay will bring chances of snow showers back to the snowbelt late on Monday. Winds will start to pick up ahead of this next system with southwest winds gusting to around 30 mph and possibly up to 40 mph.

Temperatures will warm throughout the weekend into Monday being influenced by the high pressure. Highs on Sunday will be in the upper 20s and low 30s with Monday seeing temperatures just above freezing for most of the region. Lows will stay around the upper teens and low 20s through the weekend. Winds chills will be a factor Monday morning with the gusty winds dropping the wind chill down into the low single digits.

LONG TERM /TUESDAY THROUGH THURSDAY/
Tuesday will bring the aforementioned low pressure system and associated cold front across the region with increased chances of snow showers for most of the region. The upper level trough will be fairly slow moving resulting in an extended period of lake effect snow showers for most of the snow belt. Not expecting a lot of accumulation at this time, but with the persistence of the system, will have to monitor it. During the middle of the week, a few of the models are showing a clipper system move through the Great Lakes region, through there are still some discrepancies among them such as timing, thought it might be worth a mention.

Temperatures Tuesday will continue the trend of staying around and above freezing with highs in the mid 30s. Through the middle of the week behind the cold front temperatures will drop slightly with highs being in the mid to upper 20s. Lows will be in the teens for most of the week while dropping a bit towards the end.

AVIATION /06Z Friday THROUGH Tuesday/
W'erly to NW'erly flow aloft is expected through 06Z/Sat. A weak disturbance will advance E'ward across our area through ~03Z/Sat. Thereafter, a ridge builds from the western Great Lakes and vicinity. At the surface, a ridge affects our region as its axis moves from near the Upper MS Valley to near northeastern NY and the central Appalachians. Our regional surface winds trend around 5 to 15 knots through the TAF period and will back gradually from W'erly to SW'erly.

Widespread low clouds with ceilings mainly in the 2kft to 3.5kft AGL range are expected to scatter-out or dissipate generally from west to east late Fri morning or during Fri afternoon.
Primarily fair weather is expected through 06Z/Sat. However, light lake-effect snow showers (LES showers) streaming ESE'ward from Lake Michigan will impact KTOL periodically through ~10Z/Fri, while light LES showers ending from WNW to ESE downwind of Lake Erie are expected to impact portions of NE OH/NW PA, including KCAK/KYNG, through ~10Z/Fri before increasingly drier air overspreads our region generally from the west. Visibility is expected to vary between VFR and MVFR in LES showers.

Outlook...Periodic snow with non-VFR possible this Saturday through Tuesday.

MARINE
With temperatures remaining below freezing for the next couple of days, there will be favorable conditions for moderate ice growth across the lake. Winds will continue to be out of the west to southwest at 10 to 15 knots, which will cause ice to drift easterly and could close shipping channels on Lake Erie.

Winds will increase on Saturday to 15 to 25 knots ahead of a surface cold front and will remain westerly through the weekend. On Monday, winds will begin to increase and areas from the central basin eastward could see winds up to 30 knots through late Monday. Winds have been trending upwards during the period, so will need to continue to monitor for the potential for gales in the previously mentioned areas. Winds will continue to decrease through Tuesday to 15 to 20 knots out of the west.

Small Craft Advisory issuance remains suspended until further notice for nearshore waters from Maumee Bay to Ripley, NY due to extensive ice cover.

CLE WATCHES/WARNINGS/ADVISORIES
OH...None.
PA...None.
MARINE...None.