Area Forecast Discussion

WHAT HAS CHANGED

Periodic rain chances are expected across the area through Sunday afternoon with some bouts of heavier rain. Localized flooding will be possible where multiple rounds of heavy rain occur.

KEY MESSAGES

1) Several rounds of rain with some embedded thunderstorms are expected through Sunday evening, bring some potential for heavy rainfall and localized flooding. The best chances for flooding will be areas further south and west.

2) A cool, fall pattern will develop for the bulk of the week with some intermittent rain chances, especially on Tuesday and Wednesday.

DISCUSSION

KEY MESSAGE 1... With a warm front over the area, several mid-level shortwaves will move through the region along with a low pressure system through the Ohio Valley. This pattern will allow for several rounds of rain activity through Sunday evening. Overall, the thunder and severe weather potential is limited, as ongoing and expected additional activity will keep instability down across the region. However, there remains plenty of moisture in the atmosphere, as forecast soundings indicated precipitable water values of 1.80-2.00" across the area. Therefore, any rainfall has the potential to be efficient. Any flooding concerns will be limited to where rounds of rain can persist over the next 24-30 hours. However, for our area, the setup is trending to allowing several gaps in the rain coverage at times and the better chances for flooding could be areas south and west.

KEY MESSAGE 2... Behind the weekend system, the pattern will shift to a more fall-like pattern starting on Monday with cool high pressure building from the north and a cooler trough entering from the northwest. This will allow for temperatures to fall into the 60s for much of the week and lows in the 40s and 50s. There could be some potential for rain, mainly on Tuesday and Wednesday, as a trough will remain over the Ohio Valley and could allow for some rain to build north into the area, as the high pressure system retreats slightly north. High pressure will build back in on Thursday and try to dry out the forecast toward the end of the week.

AVIATION /18Z Saturday THROUGH Thursday/

Multiple rounds of rain showers with a low embedded thunder risk through the TAF period. Initially, we are starting with mainly VFR conditions with pockets of MVFR/IFR due to mainly lower visibilities this afternoon/evening but will trend towards IFR/LIFR late tonight into Sunday due to lower ceilings. Heavier rain accompanied by isolated lightning will be difficult to predict in this pattern but is most most likely very late tonight into Sunday morning.

Southeast winds of 5-10 knots will trend toward southwest tonight before becoming north by late Sunday morning into early Sunday afternoon.

Outlook...Non-VFR possible with showers and occasional thunderstorms through Thursday.

MARINE

A warm front continues to lift north toward the lake this afternoon and will largely stall out over the lake tonight. Winds will be a mix of east to southeast flow across the region and the slight offshore flow should allow for low waves through tonight. Low pressure will move through the Ohio Valley on Sunday and drag the front south, allowing for north to northeast flow to develop on the lake. Winds will reach 15 to 20 kts on Sunday afternoon and resultant waves will begin to build for 4 ft or greater. With high pressure to the north and a trough over the Ohio Valley, a strong pressure gradient will set up for Monday into Tuesday, allowing for northeast flow of 25 to 30 kts over the lake. There is some low end potential for gales, depending on the strengths of these systems. Regardless, waves will build substantially on Monday and Tuesday. The trough to the south will try to build north on Wednesday and shift flow to the east, while staying in the 15 to 20 kt range. Overall, a long period of marine headlines will be expected starting on Sunday and continuing through the middle of the week.

CLE WATCHES / WARNINGS / ADVISORIES

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