textproduct: Cleveland

WHAT HAS CHANGED

No major changes to the forecast.

KEY MESSAGES

1) Quiet weather will continue through Saturday with warming temperatures.

2) Widespread showers and thunderstorms expected Saturday night into Sunday, with an active pattern continuing through next week that will bring multiple precipitation chances and variable temperatures.

DISCUSSION

KEY MESSAGE 1... Broad mid/upper troughing over the northern tier of the CONUS will continue to supply cooler conditions through tonight, and as surface high pressure drifts across the Ohio Valley, the clear skies and relatively light winds will allow for a refreshingly cool night as lows dip into the upper 50s/low 60s.

The surface high will quickly shift into the Mid Atlantic region Saturday as the active mid/upper trough over the northern tier sends another shortwave and associated cold front into the Great Lakes. This will allow for southerly return flow, boosting highs into the mid/upper 80s in most areas Saturday, except low 80s will persist in far NE Ohio and NW PA. The good news is that dew points will remain tolerable, so it will still be a fairly pleasant day under lots of sunshine.

KEY MESSAGE 2... The aforementioned mid/upper shortwave will drop through the central and southern Great Lakes Saturday night and Sunday morning, with coupling of two 80-90+ knot H3 jet streaks inducing a strengthening surface low near southern Ontario Sunday morning that will lift through the eastern Great Lakes through the day. This will drag a strong cold front through the region by midday Sunday. The jet coupling and associated strong upper divergence will lead to unseasonably strong frontogenetic forcing, so rain should be pretty widespread late Saturday night into much of Sunday before drying out from west to east Sunday night. Abundant cloud cover and rain combined with the early day frontal passage should greatly limit any severe weather threat, but PWATs increasing to seasonably high values of 1.25 to 1.50 inches along with the forcing and weak instability could lead to some moderate to heavy rain in embedded convection. This will take care of the recently dry conditions for those who have missed out on the convection of the past few days. The current, projected track of the low and best forcing beneath the coupled jet structure would place the heaviest swath of QPF near the lakeshore, where amounts of 0.50 to 1 inch are possible, with lesser amounts of a few tenths to up to 0.50 inch farther south. This will be fine tuned with later forecasts.

Much cooler and drier conditions are expected in the wake of the front Sunday night into Tuesday as the mid/upper trough deepens across the central and eastern CONUS and surface high pressure takes control. This will support highs mainly in the 70s and lows in the 50s. However, that broad mid/upper longwave trough will keep the pattern active as additional shortwaves rounding its base send reinforcing cold fronts across the region. A weak cold front Tuesday night into Wednesday could bring a few showers and thunderstorms, but the more interesting shortwave and associated cold front looks to be Wednesday night or Thursday, when stronger jet support induces a deepening surface low. This could bring stronger thunderstorms and heavy rainfall depending on the frontal timing, degree of shear, and how much instability can advect northward. Temperatures mid to late next week will be a bit variable due to the frontal passages, but generally upper 70s to low 80s are expected.

AVIATION /18Z Friday THROUGH Wednesday/

VFR across the TAF sites this afternoon with VFR to persist through the TAF period. Only anticipating isolated pockets of few to sct ceilings around ~4kft through sunset. Otherwise, mainly clear skies overnight, with high cirrus filling in by Saturday afternoon. Winds are out of the west this afternoon, 10 to 15 knots with gusts generally around 20 to 22 knots. Winds will diminish to 5 knots or less overnight, increasing again out of the southwest Saturday afternoon, 10 to 12 knots.

Outlook...Non-VFR likely in showers and thunderstorms on Sunday. Non-VFR chances may return Tuesday afternoon and evening in scattered showers and thunderstorms, becoming more likely late Wednesday in showers and thunderstorms.

MARINE

Marine conditions will gradually improve this evening as west winds shift towards the southwest and subside to less than 15 knots. Winds will shift towards the northwest behind a cold front late Sunday into Monday with waves nearing 3 feet. Although the Small Craft potential remains low for this time frame, it is non-zero. A higher risk for more widespread hazardous marine conditions will arrive by mid-week as a strong low pressure system develops and moves east into the Great Lakes region Wednesday into Thursday. Will continue to monitor trends for this system, though there is potential for west to southwest winds to exceed 30 knots at times.

CLE WATCHES/WARNINGS/ADVISORIES

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