textproduct: Cleveland

WHAT HAS CHANGED

Patchy fog and low clouds are expected across the area this morning. Rain chances for Saturday have increased a little bit.

KEY MESSAGES

1) Showers with some isolated storms are possible this afternoon and evening, mainly along and south of US 30 in Ohio. Severe weather and flooding hazards are not expected at this time.

2) Humid conditions with shower and storm chances will return on Saturday. There is some potential for a stronger storm during Saturday afternoon and evening.

DISCUSSION

KEY MESSAGE 1... A frontal boundary will approach and stall out over the forecast area today. On the north side of the boundary, the air mass will moderate a little with temperatures in the 70s and dew points falling a bit into the 60s and maybe upper 50s. However, the south side of this boundary will remain humid and relatively unsettled with highs near 80 degrees and dew points in the 70s. This air mass will remain favorable for more shower and storm development this afternoon and evening. The bulk of the development should be south of the forecast area where greater instability will build. However, some activity will develop across the southern portion of the forecast area with a mid-level shortwave moving through the region. With a limited thermodynamic environment and storms should progress with the shortwave, severe weather and flooding hazards remain very low at this time. The surface boundary will push south for Thursday night into Friday with high pressure entering the region, which will allow for 36 hours of dry, comfortable weather.

KEY MESSAGE 2... Unsettled weather will return to the Ohio Valley for Saturday as a mid-level shortwave will move through the Ohio and Tennessee Valleys behind Friday's high pressure system. This wave will allow for a warm front to lift back over the area, allowing temperatures back into the 80s and dew points back in the 60s to lower 70s. This shortwave will provide some lift for shower and thunderstorm development, especially on Saturday afternoon and evening. With activity currently expected during peak heating hours, there is a low end threat for a stronger thunderstorm, as the atmosphere may be unstable enough to allow for some gusty winds to materialize. However, details may change over the next couple of forecast cycles, especially if timing is faster or slower or if the wave is less aggressive in lifting the warm front north. Activity could linger into Sunday with a cold front trying to approach from the northwest, extending from a low pressure system moving through Canada. Return flow is aggressive across the region early next week and may try to keep this feature north, as the main frontal support quickly departs to the northeast. If the front doesn't reach the area, the area may end up staying dry with activity to the north.

AVIATION /12Z Thursday THROUGH Monday/

Mixed-bag of VFR, MVFR, and IFR across the TAF sites this morning, associated with both low ceilings and patchy fog/mist. Conditions will gradually improve to VFR through this morning. Conditions may be favorable for patchy fog/mist to develop again late tonight into Friday morning and have introduced MVFR vsbys for this update. A few rain showers remain possible later this afternoon and evening, mainly along and south of US-30, though non- VFR impacts are not anticipated.

Winds are generally out of the west to southwest this morning, 4 to 7 knots. Winds will remain out of the west to southwest into this afternoon, before becoming light and variable or favoring a weak northwest direction overnight.

Outlook...Non-VFR possible in low ceilings and/or patchy fog Friday morning. Non-VFR possible again on Saturday in isolated to scattered showers and thunderstorms.

MARINE

A stalling frontal boundary will eventually settle south of the lake today. Winds behind this boundary will veer from the west to the north with time today. High pressure will build into the region tonight and winds will become northeast and increase a bit to 10 to 15 kts. Waves could pick up a bit with the long fetch flow over the lake, but it may just result in an elevated swimming risk overnight. The high moves east for Friday, allowing for easterly flow. Southerly flow will return starting Friday night through Saturday night with a warm front moving back across the lake. A cold front will attempt to cross the lake on Sunday, bringing westerly flow again to the region. However, it is possible that this feature gets stuck north of the lake and southerly flow will persist into early next week. There is a bit of uncertainty in the pattern for early next week to be too confident on the mean wind direction on the lake. Overall, not expecting any marine headlines at this time but there may be some periods of moderate swimming risk.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...None.