textproduct: Cleveland

WHAT HAS CHANGED

Increased the sky cover and duration this morning into the early afternoon hours due to persistent low stratus that will not be able to mix out very easily.

KEY MESSAGES

1) High pressure influences continue for today with northeasterly flow off Lake Erie keeps the western lakeshore areas and inland on the cool side.

2) A cold front comes through Tuesday with showers and thunderstorms ahead of it Monday night, and a prolonged cool down with a cutoff upper level low pressure system for the end of the week and into next weekend.

DISCUSSION

KEY MESSAGE 1... Low level moisture continues to be trapped under a stout subsidence inversion this morning, and without the ability to reach temperatures required to mix out the inversion, this should prove to be very difficult to erode. This is likely to happen after 16Z today, and possibly closer to 19Z. The 925mb northeasterly flow continues to advect moisture in to the region underneath this inversion and shows the source of that moisture drying up in the 18Z time frame. Cool weather expected to persist today, especially downwind of the northeasterly fetch off chilly Lake Erie that will make 60F a difficult reach for the western half of the lakeshore cities, and inland a couple counties in northwest Ohio. Away from this chilly source region, late sun should be enough te get temperatures into the upper 60s in the mid to late afternoon hours. The forecast is dry through Monday, but surface winds turning southerly brings back warmer conditions ahead of a cold front that will bring renewed convection chances Monday night.

KEY MESSAGE 2... Mid/upper level ridge exits late Monday into Monday night, replaced by southwest flow aloft. Low level winds will be on the increase as this frontal system approaches, and instability should be on the increase as well. Prefrontal surface trough Monday night likely to be the first wave of showers and isolated thunderstorms, then followed by another wave of showers and isolate thunderstorms with the cold front itself Tuesday. Back into the 50s for several days in the wake of the cold front from midweek into next weekend as an upper level low pressure system drops into the Great Lakes and becomes cut off east of the CWA. Low end POPs in the cold pool convection setup. Possible frost/freeze issues under this upper level low for the end of the week and into the weekend.ason.

AVIATION /12Z Sunday THROUGH Thursday/

MVFR/IFR ceilings are widespread across the area this morning with pockets of LIFR ceilings along the lakeshore. Satellite observations and forecast soundings indicate a deep layer of moisture in the low levels, with mid- level subsidence aloft. As a result, IFR/MVFR ceilings will persist until around 18Z before scattering out.

Outlook...Periods of showers with non-VFR conditions are expected Monday night through Thursday morning. Scattered thunderstorms are expected Monday night through Wednesday afternoon.

MARINE

High pressure to our north will track eastward today and exit the region Monday. Waves of 1-3 feet are expected with northeasterly winds around 10 to 15 knots. Patchy fog is expected over Lake Erie through late this morning as colder and fairly moist air crosses the lake.

Monday night through Wednesday morning low pressure will track northeastward from the Upper MS Valley to Hudson Bay. Winds will shift from easterly/southeasterly at 15 to 25 knots to southerly/southwesterly at 10 to 20 knots. Waves 3 to 6 feet are expected Monday night into Tuesday morning, then subside gradually to 3 feet or less the rest of Tuesday through Wednesday morning. A Small Craft Advisory may be required.

A trough will linger over Lake Erie Wednesday before high pressure builds across the north-central United States Wednesday night through Thursday. Westerly to northwesterly winds 5 to 15 knots and waves 1-3 feet are expected.

CLE WATCHES/WARNINGS/ADVISORIES

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