textproduct: Cleveland

WHAT HAS CHANGED

No major changes from the previous forecast cycle. The weekend continues to trend slower, which may allow for most of the area to be dry during the daytime hours on Saturday.

KEY MESSAGES

1) Seasonable last day of July is expected today with some isolated rain chances in interior Northeast Ohio this afternoon.

2) Showers and storms activity will increase through the weekend, especially late Saturday into early Sunday. Locally heavy rainfall is possible where any repeated or training thunderstorms occur.

3) Daily, scattered rain chances and near normal temperatures are expected for Tuesday through Thursday.

DISCUSSION

KEY MESSAGE 1... High pressure will continue to move east across the area today. This will allow for return flow and additional moisture to enter the region. High temperatures will be warmer today in the 80s for most with some isolated highs near 90. The combination of temperatures approaching convective temperatures, additional moisture with dew points in the 60s, and a lake breeze could allow for some showers to form in interior Northeast Ohio. Coverage will be fairly limited, but will maintain some low PoPs. For most, it will just be a dry, typical late July day.

KEY MESSAGE 2... The main weather concern for the entire forecast period will be a low pressure system that will move through the region starting on Saturday and not fully exit until Monday evening. This system continues to trend slower with the 00z guidance and much of the forecast area may end up staying dry during the daytime hours on Saturday with just some scattered activity in the western half of the forecast area. The bulk of the rain and storm activity seems to be honing in on Saturday night into Sunday. The environment with incoming low and upper trough moving through the region will be favorable for efficient rainfall with PW values over 2 inches in some model soundings in Northwest and North Central Ohio. Storms should be progressing across the region, despite the sluggish low. However, there is enough forcing to get multiple storms to develop and there is concern for training storms, which could pose a flood risk. Portions of the western forecast area are in a Day 2 Slight Risk for excessive rainfall to highlight the heavy rain and flash flood potential on Saturday night. Portions of NE OH and NW PA are in a Day 3 Slight Risk for excessive rainfall as rain will continue on Sunday for the eastern half of the area. The system will exit by Monday and have PoPs trending down Sunday evening and onward.

KEY MESSAGE 3... For next week, the upper trough that supported the system through the region this weekend will become elongated and then get pinched off from the main upper flow moving through eastern Canada. This will allow for a cut off upper low to form over the central Appalachians. With this feature to the southeast of the forecast area, tough to be highly confident in rain chances. However, this feature could provide just enough lift in a typical summer atmosphere to generate some scattered showers and maybe some storm. The best chance for any rain would be during the daytime hours with help from peak heating.

AVIATION /12Z Friday THROUGH Tuesday/

Isolated patchy fog is bring observed in a few sites this morning, reducing visibilities to 5SM. These conditions should quickly improve this morning as daytime heating allows for mixing. Widespread VFR conditions are expected after that for this TAF period. There is a chance of showers at KYNG and KCAK this afternoon which were handled with VCSH given the timing and coverage uncertainty. High clouds begin to build over the region this afternoon as a low pressure system begins to approach from the west. Winds will remain light and variable through the period.

Outlook...Non-VFR conditions in showers and thunderstorms are expected Saturday afternoon through Sunday.

MARINE

Pleasant marine conditions are expected across Lake Erie today as high pressure remains over the region. Light winds with a southerly component will result in waves less than 1 foot. A low pressure system will move into the region on Saturday and Sunday shifting winds to easterly at 10-15 knots for much of the weekend before becoming northerly late Sunday. Waves through the weekend will generally linger in the 1-3 foot range, although once the flow becomes onshore a few higher waves will be possible. Right now the forecast keeps conditions sub- criteria for Small Craft Advisory, but will need to continue to monitor in coming days for any potential enhancement in the winds and waves. By the start of next week, high pressure will return along with calm marine conditions.

CLE WATCHES/WARNINGS/ADVISORIES

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