Marine Weather and Tide Forecast for Powell, OH

NEAR TERM /THROUGH TONIGHT/
Widespread shower activity will continue to spread northeast across our area through this afternoon in association with an upper level low lifting north over lower Mississippi Valley. These showers are moving into a drier airmass so the northern edge will continue to be slow to fill in/saturate. The clouds and pcpn have limited any instability, so think any thunder chances look fairly minimal at this point. As we head into tonight and start to lose the diurnal enhancement, expect the shower activity to gradually decrease in coverage and taper off. We will remain cloudy overnight and this will help keep temperatures mild with overnight lows mostly in the lower 60s.

SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/
The upper level low will lift up into the lower Ohio Valley through the day on Tuesday before beginning to open up as if shifts into the lower Great Lakes through Tuesday night. A stronger axis of mid level vorticity will pivot up around the low through the day on Tuesday.
This will combine with daytime heating/instability to allow for more widespread shower and embedded thunderstorm activity to develop from late morning on into the afternoon. With the CAPE remaining quite skinny and very light flow through the mid levels, the potential for locally heavy rainfall will be possible with the thunderstorms. The clouds and pcpn will once again help keep temperatures down a bit with afternoon highs in the low to possibly mid 70s. Pcpn should then gradually taper off again heading into Tuesday night as we lose the diurnal enhancement. Lows Tuesday night will be in the upper 50s to lower 60s.

LONG TERM /WEDNESDAY THROUGH MONDAY/
A closed low over CWA begins the period, tracks slowly north into lower MI during the day and then northeast overnight. A trough extending se from this low will also move e and away from CWA through this same time. Weak ridging behind the upper trough will peak Thurs evening with falling heights through Sat morning.
Overnight Fri will see s/w energy skim the northern CWA as it rotates around an upper low near/n of Lk Superior. Heights will rise slightly as zonal wly flow replaces it on Sat, then rise a little more Sun/Sun night as a ridge builds in the central U.S.

As the ridge develops Sat night, models diverge in the characteristics of the ridge. GFS is quicker and more amplified, while the Euro and Canadian look to be slower, less amplified, and negatively tilted. Temps in the NBM forecast look to split the difference between models from Sun onward, with wide variability between 4 sigma levels through each of the periods.

Until Sunday, temperatures look to be in line wrt model and operational forecasts, so only minor adjustments were made this afternoon. Through that time, Thurs and Fri will be the peak in the forecast with low-mid 80s, cooling down through Sun into the mid 70s. Lows in the low 60s Wed/Fri overnight will sandwich a balmy upper 60s Thurs night. Sat night onward currently has low-mid 50s in the north and upper 50s in the south.

A cold frontal passage Thurs night should bring the highest threat for stronger storms in the region.

AVIATION /19Z MONDAY THROUGH SATURDAY/
More widespread showers have been slowly overspreading the area from the southeast this morning into early afternoon in association with an upper level low pressure system over the lower Mississippi Valley. The pcpn is moving into a drier airmass so it is still fairly light and the cigs are still VFR. As we saturate through late afternoon, do expect pcpn to become more significant and cigs to eventually fall into MVFR category. Suppose it will be tough to rule out an embedded thunderstorm later this afternoon into early evening, but chances appear low enough to leave out of the TAF forecast. Otherwise, with some diurnal component to the showers, expect to see an overall dissipating trend heading into tonight, although MVFR to locally IFR cigs will persist tonight into Tuesday morning. More widespread showers and embedded thunderstorms will then develop heading into Tuesday afternoon as cigs lift back into VFR.

OUTLOOK...Thunderstorms are possible at times through Wednesday, then again on Thursday night. MVFR ceilings are expected Tuesday morning, and then possible again Wednesday morning.

ILN WATCHES/WARNINGS/ADVISORIES
OH...None.
KY...None.
IN...None.