Marine Weather and Tide Forecast for Gratiot, OH

KEY MESSAGES
1) Scattered showers and gusty thunderstorms early this morning, then dry

2) Severe weather potential tonight into early Thursday, with a more limited potential south of PIT Thursday afternoon. Gusty wind potential continues Thursday

3) Dry Friday and Saturday, with rain chances increasing again Sunday

DISCUSSION
KEY MESSAGE 1...
A shortwave continues to track east across the region early this morning. Showers and a few gusty thunderstorms will continue as the wave crosses. Instability is minimal, with a MU CAPE 250 j/kg or less, though the convection is on the leading edge of a low level jet, which was maintaining the showers/storms. This wave should exit the region around sunrise, with showers and thunderstorms ending.

Flat shortwave ridging and a strong cap should result in dry weather for the remainder of the day, with high temperatures near seasonable levels.

KEY MESSAGE 2...
The next shortwave trough is expected to advance across the Midwest today into this evening, as surface low deepens ahead of it. A significant severe weather outbreak is expected to be ongoing to our west this afternoon and evening in the warm sector, as a strong low and mid level jet sets up across the region. This jet is expected to strengthen as it tracks across the Upper Ohio Valley region tonight. Winds at 850mb are progged from 55-65 kt, with similar wind at 700mb. Overall instability is progged to decrease overnight as the convection moves east along a pre frontal trough, though ensemble MU CAPE still shows around 500 j.kg available. Some CAMS indicate enough mixing with the strong flow aloft to maintain a similar surface based CAPE as well.

Even with the lowering levels of instability, the strong flow aloft should result in 0-6km shear from 50-70kt. Directional shear is also expected, resulting in curved hodographs. The highest potential for severe weather is expected to be across Ohio, where the greatest instability is progged. There remains some question on how far east the severe potential will continue. Think some CAMS weaken the convection too quickly given the environment. The latest convective outlook from the Storm Prediction Center continues to carry the Slight Risk for severe storms into eastern Ohio, with the Marginal into western PA and norther WV. This could be adjusted through the day depending on the convective development to the west and the amount of destabilization that occurs across the Upper Ohio Valley region. At this time, damaging wind appears to be the main hazard, though isolated tornadoes and large hail will also be possible. The potential for flooding continues to lower with a more progressive storm mode.

The initial convection should exit the region Thursday morning with the prefrontal trough. The surface low will continue it's northeastward track to eastern Ontario, and will pull a cold front across the Upper Ohio Valley region. Dry advection and capping warmth aloft will likely preclude additional thunderstorms across most of the area for the rest of the day.
The exception will be mainly south of I-70, where some additional convection is possible in the afternoon in the vicinity of the cold frontal boundary. SPC has trimmed more of the area out of the Slight Risk for severe storms, which seems reasonable given the recent model trends. Damaging wind would be the main threat for any storms that develop, with the continued strong flow aloft.

Mixing will likely bring down strong wind gusts even outside of convection on Thursday. BUFKIT momentum transfer, and model ensemble probabilities of advisory level gusts, have decreased some in recent model runs. Maintained gusty winds in the grids, with sub advisory levels at this time. There is still a potential that a wind advisory will be needed, but do not have the confidence in advisory level gusts (greater that 45 mph) at this time.

KEY MESSAGE 3...
Dry weather returns Friday and Saturday as high pressure builds across the region. More widespread rain chances return Sunday into Monday as low pressure tracks across the region.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
A crossing shortwave, low level jet, and minimal instability will maintain showers and thunderstorms tracking across the region early this morning. This activity should quickly move east of the region by sunrise as the shortwave exits. Otherwise, VFR is expected the rest of the daytime hours under shortwave ridging and strong capping aloft. Expect scattered cumulus and increasing high clouds through the day ahead of the next approaching shortwave. Mixing and increasing flow aloft should result in gusty SW wind today as well.

A deepening surface low is expected to track across the Midwest into southern Ontario tonight into Thursday. A prefrontal trough, strong low level jet, and instability should result in MVFR/local IFR conditions as showers and thunderstorms overspreading the region tonight. Some of these storms could be severe, with a strong low-mid level jet in place aloft.

Outlook...
Restrictions are expected to continue into Thursday morning as the showers and thunderstorms gradually exit the region.
Showers and storms could redevelop, especially in the afternoon, south of a ZZV-LBE line as the low's cold front drops south across the region. In addition, strong WSW wind could gust from 30-40 kt through the day as the strong winds aloft mix down.

Diminishing wind is expected Thursday night, with VFR conditions then returning through Saturday under building high pressure. Restrictions in showers and thunderstorms are possible Sunday with approaching low pressure.

PBZ WATCHES/WARNINGS/ADVISORIES
PA...None.
OH...None.
WV...None.