Marine Weather and Tide Forecast for Avonia, PA

NEAR TERM /THROUGH THURSDAY/
Only very minor changes made to the Noon update. Raised the maximum temperature a degree or so. Left the slight chance POPs in the TOL as convection near the IN/MI line might brush that region in the afternoon.

Previous forecast: Current forecast is on track with a much warmer day expected.
Temperatures at 850 mb support the current afternoon predictions. Convection over the CHI area and southern end of Lake Michigan is weakening as it moves into southern lower MI and extreme northern Indiana. Some of this activity may approach nw Ohio this afternoon.

The near term forecast period appears largely uneventful. High pressure over the region will move east today and allow a warm front to enter west of it. This front could generate some convection but the bulk of the activity should be across Lower Michigan. Have some low PoPs (20%) for the Toledo metro for late this afternoon, but the overall trends are drier for Ohio. High temperatures will be in the 70s across the area. A lake breeze should develop this afternoon and temperatures will cool along the NE OH/NW PA shorelines during the afternoon hours with winds off Lake Erie. Skies should clear for tonight and temperatures will fall into the 50s. High pressure will rebuild southwest for Thursday and highs should achieve the 70s to lower 80s with clear conditions. A stronger lake breeze should form on Thursday afternoon.

SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/
Aloft, one shortwave trough should sharpen and approach our CWA from the central Great Plains on Thursday night through Friday before shifting farther E'ward and across our region Friday night.
During Friday night, a separate shortwave trough axis should approach our region from the northwestern Great Lakes. At the surface, attendant troughing impacts the Lake Erie region and Upper OH Valley. A surface low accompanying the first shortwave through should wobble NE'ward from the central Great Plains to the Upper MS Valley Thursday night, then wobble NE'ward from the central Great Plains to the Upper Saint Lawrence River Valley via the Lake Erie region between sunset Thursday evening and daybreak Saturday morning. This low track should allow a surface warm front to sweep N'ward across our CWA during the daylight hours of Friday before the front stalls in vicinity of the international border of Lake Erie early Friday evening. During Friday night, the low's trailing surface cold front should sweep SE'ward across our CWA Periods of showers and thunderstorms are expected Thursday night through Friday night as instability, including elevated instability, is released by the following: moist isentropic ascent along the upper-reaches of the warm front and ahead of the shortwave trough axes; low-level convergence/moist ascent along the cold front. Some thunderstorms may be strong to severe amidst weak to moderate MUCAPE and moderate to strong deep layer bulk shear.

Low-level WAA ahead of and behind the warm front should contribute to Thursday night's lows reaching the 50's to lower 60's around daybreak and late afternoon highs reaching mainly the 70's on Friday. Low-level CAA behind the cold front should contribute to overnight lows reaching the mid 40's to lower 50's around daybreak Sunday.

The second above-mentioned shortwave trough axis and attendant surface trough axis should sweep SE'ward across our region on Saturday morning through early afternoon. Behind the shortwave trough, a ridge at the surface and aloft should build from the Upper Midwest and vicinity through Saturday night. Moist isentropic ascent preceding the shortwave trough axis and low-level convergence/moist ascent along the attendant surface trough axis should release very weak, yet sufficient instability to trigger isolated to scattered rain showers in our CWA during the morning through early afternoon.
Behind the shortwave trough axis, fair weather is expected through Saturday night as stabilizing subsidence overspreads our CWA
Daytime highs on Saturday should reach the lower 50's to lower 60's as the CAA regime at the surface and aloft persists. Considerable clearing and easing surface winds should promote fairly efficient nocturnal cooling Saturday evening through daybreak Sunday, when lows should reach mainly the upper 30's to mid 40's in northern OH and the mid 30's to lower 40's in NW PA. The coldest lows are expected in the valleys of interior NW PA. This is where patchy frost may form.

LONG TERM /SUNDAY THROUGH TUESDAY/
The ridge at the surface and aloft should continue to impact our region through Monday. The surface ridge axis should move from the eastern Great Lakes and Upper OH Valley to near the Canadian Maritimes, while the ridge axis aloft should shift from the Upper MS Valley toward the central Great Lakes and vicinity. Current odds favor fair weather through Monday as stabilizing subsidence accompanies the ridge. Weakening low-level CAA should give way to low-level WAA on Sunday as the low-level ridge axis traverses our region from west to east. Low-level WAA then persists through Monday as our region becomes located along the western flank of the low- level ridge. Sunday's late afternoon highs should reach the mid 50's to upper 60's. The coldest highs are expected along and within several miles of Lake Erie since a weak synoptic MSLP gradient and sufficient daytime heating of surface air over land surrounding ~49F Lake Erie should permit lake breeze development during the late morning through early evening. Overnight lows should reach the 40's to lower 50's during the wee hours of Monday morning before readings begin to moderate toward daybreak as the low-level WAA strengthens.
Daytime heating amidst the stronger low-level WAA are expected to allow Monday's late afternoon highs to reach mainly the 70's to near 80F in our CWA However, a Lake Erie lake breeze should develop and extend several miles inland in far-NE Cuyahoga County to Erie County, PA. Highs should reach the mid 60's to lower 70's in the lake breeze.

The ridge at the surface and aloft should begin to exit E'ward Monday night through Tuesday as a trough aloft approaches from the northern/central Rockies and Great Plains. This will allow SW'erly flow aloft, embedded shortwave disturbances, and attendant/subtle surface trough axes to impact our CWA In addition, an attendant surface low should wobble NE'ward across the Upper Midwest and northern Great Lakes, and perhaps move farther NE'ward toward James Bay while deepening downstream of the longwave trough axis aloft.
Isolated to scattered showers and thunderstorms are possible overnight Monday night through Tuesday due to the release of weak to moderate instability, including elevated CAPE, via moist isentropic ascent ahead of the shortwave trough axes and low-level convergence/moist ascent along the surface trough axes. The aforementioned instability, steep mid-level lapse rates associated with an EML plume, and moderate to strong deep layer bulk shear may allow thunderstorms to become severe. Low-level warm/moist air advection from the Gulf is expected to intensify Monday night through Tuesday due to a tightening MSLP gradient between the departing surface ridge and deepening surface low. Lows should reach the mid 50's to mid 60's around daybreak Tuesday. Intervals of sunshine should contribute to highs reaching mainly the upper 70's to mid 80's Tuesday afternoon.

AVIATION /18Z Wednesday THROUGH Monday/
VFR conditions are observed and are expected to continue through the TAF period. FDY has been reporting vsby restrictions at times...likely due to agricultural activity near the field. The vsby is currently back to unrestricted, so did not include this in the TAF. Will monitor decaying convection moving east across northern IN/southwest MI and a warm front for an isolated shower or storm near TOL between 19-00z, though confidence remains below 30% for impacts to the field so continue to omit.

Light, generally westerly winds at 6-12kt this afternoon, except for CLE and ERI which are impacted by a lake breeze. Winds generally go light at 5kt our less out of the south-southeast tonight. Southerly winds increase to 6-12kt on Thursday, with a lake breeze likely at ERI and possible at CLE in the afternoon.

Outlook...Non-VFR possible in scattered to widespread showers and thunderstorms Friday into Saturday.

MARINE
A ridge affects Lake Erie through Thursday night as the ridge axis moves from the eastern Great Lakes toward New England. A weak MSLP gradient accompanying the ridge will allow winds to trend variable in direction and around 5 to 10 knots in magnitude through Thursday.
Winds will trend onshore during the late morning through early evening hours of today and Thursday due to lake breeze development.
Winds become primarily NE'erly to SE'erly around 5 to 15 knots Thursday night. Waves of 2 feet or less are expected through Thursday and waves of 3 feet or less are forecast Thursday night.

A low is expected to move E'ward from the Upper MS Valley to near western Lake Erie on Friday. This will allow a warm front to sweep N'ward and then stall near the international border in Lake Erie by early Friday evening. The warm front's passage is expected to cause E'erly to SE'erly winds around 10 to 15 knots ahead of the front to veer to S'erly to SW'erly behind the front as waves remain 3 feet or less. The low should move ENE'ward across Lake Erie and toward the Upper Saint Lawrence River Valley Friday night. This should allow the trailing cold front to sweep SE'ward and away from Lake Erie.
Primarily S'erly to SW'erly winds around 10 to 20 knots over U.S.
waters should veer to NW'erly with the cold front's passage. Waves of 1 to 3 feet with occasional 4 footers are expected and a Small Craft Advisory may be needed.

Behind the cold front, a ridge builds gradually from the Upper Midwest through this Sunday. Accordingly, NW'erly winds around 10 to 20 knots at daybreak Saturday morning are expected to veer gradually to E'erly to SE'erly and ease to 5 to 15 knots through Sunday.
Accordingly, waves of mainly 3 feet or less are expected, but occasional 4 footers are possible through the daylight hours of Saturday.

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