textproduct: Cleveland

WHAT HAS CHANGED

No significant changes to the forecast. Continuing to monitor the severe weather threat for this afternoon/evening and Saturday evening.

KEY MESSAGES

1) A warm front will lift north through this afternoon bringing showers and thunderstorms to the region with a severe weather risk mainly for areas south of I-80.

2) Another round of showers and thunderstorms are expected Saturday evening as a cold front sweeps across the region with another chance for severe weather for areas southeast of the I-71 corridor.

3) Much cooler weather expected starting Sunday through the middle of the week with a few periods of precipitation expected.

DISCUSSION

KEY MESSAGE #1:

A warm front will lift across the region this afternoon resulting in temperatures rising up into the mid to upper 70s and dew points climbing along with it into the low 60s. A weak frontal boundary will enter in from the northwest and stall across the lake shore this evening. This will generally serve as the boundary where much of the precipitation and severe weather potential will occur to the south. It's difficult to map out where this feature will stall out, though the recent trends have it further south towards the I-80 corridor. Around the boundary and to the north won't be completely dry as there will be a chance for a shower or two creating damp conditions. On the note of severe weather, with the increased temperatures and dew points, there will be MUCAPE values around 1500 J/kg from the I-80 corridor southward. Low level lapse rates will be decent, around 6.5-7 C/km, creating a threat for damaging winds and large hail. In addition to the severe weather threat, there will be a marginal risk for heavy rain across the region. This will be more concentrated in the areas with training thunderstorms and in areas that are already saturated from the past few days. The severe/heavy rain threat should wane into the evening as the better forcing moves to the north with the frontal boundary lifting.

KEY MESSAGE #2:

Another chance for severe weather comes on Saturday as the frontal boundary lifts north Friday night as a warm front and temperatures stay elevated. Temperatures will be warmer on Saturday with highs up into the mid to upper 70s with a few places touching 80 and dew points again being in the low 60s across the region. There will be plenty of instability with the warm temperatures and increased dew points. Low level lapse rates again will be around 7 C/km with 0-6 km shears values around 30-40 knots. This will support a damaging wind threat with large hail as a secondary threat. An isolated tornado can't be rules out either along the cold front as low level flow increases out of the southwest. The area with the higher potential for severe weather will be around and southeast of the I- 71 corridor. This is outlined in the new Day 2 Severe Weather Outlook with a slight risk now introduced. Locally heavy rainfall will be possible with a minor flood risk. Thunderstorms will be ongoing ahead of the front with the front itself moving in from the west around 5-7PM and will exit to the east after midnight.

KEY MESSAGE #3:

Behind the cold front Saturday night, a much cooler air mass will move in as an upper level trough remains in place over eastern Canada. High temperatures on Sunday will be in the mid to upper 40s, around 30 degrees below what they were on Saturday. There will be potential for scattered lake effect showers to Saturday and Sunday with the northwesterly flow across Lake Erie. Surface high pressure will build in briefly to the south of the region with dry weather generally expected into Monday. A shortwave will move through the region late Monday night into Tuesday that will bring a low chance of precipitation with possible rain/wet snow mix as temperatures drop just below freezing. Temperatures to start next week will be below average with highs int the 40s and overnight lows in the upper 20s to low 30s. There will be a rebound in temperatures mid week as the upper level trough moves off to the east and high pressure builds into the region.

AVIATION /06Z Friday THROUGH Tuesday/

All terminals are VFR with broken mid level clouds of 6-12K feet at 06Z. The main focus today will be timing chances of showers and thunderstorms. Scattered showers extend from near CLE to MFD to MNN at 06Z and will tend to weaken as they shift northeast through 10Z. Another area of showers and thunderstorms is located from central lower Michigan to northwest Indiana and may hold together to reach TOL/FDY prior to 11Z with decreasing intensity and coverage farther east through 13Z. These showers are likely to diminish this morning, then re-develop this afternoon after 20Z as a frontal boundary settles south into the area. Showers and thunderstorms may move west to east along this front late this afternoon into early evening, before the front lifts back north. There is uncertainty in placement of showers and thunderstorms this afternoon but seem most likely at MFD/CAK, with confidence for thunderstorms the highest at FDY/TOL in the 01-06Z time frame. Thunderstorms this evening could be heavy at times with IFR visibilities.

A low level jet with 50 knots near 2500 feet is moving overhead and most terminals are gusting to 20-30 knots. If gusts drop off for any appreciable amount of time will need to add low level wind sheer to the TAF. breezy southwest winds will continue today, with winds veering to the northwest and eventually northeast for locations that end up north of the frontal boundary.

Outlook...Non-VFR possible in scattered showers and thunderstorms Friday afternoon into Friday night. Non-VFR more likely on Saturday in showers and thunderstorms along a cold front. Low ceilings may linger through Sunday. Non- VFR may return on Monday in rain and/or snow showers.

MARINE

Southwest winds of 15 to 25 knots this morning will tend to decrease this afternoon as a trough settles south over the lake. It will take until this evening for the cold front and wind shift to the north/northeast to fully cross Lake Erie. Northeast winds veer back around to the south at 15-20 knots on Saturday as the warm front lifts back north before a stronger cold front crosses the lake Saturday night into Sunday. Waves build to 3 to 6 feet and a Small Craft Advisory will likely be needed east of Vermilion on Sunday. High pressure briefly builds over the Ohio Valley on Monday before a 3rd cold front crosses Lake Erie Monday night. Another window with possible Small Craft Advisory conditions looks possible Monday night into Tuesday on the central basin of Lake Erie.

Showers and thunderstorms accompanying the cold front Saturday afternoon and evening could pose a threat of strong winds.

CLE WATCHES/WARNINGS/ADVISORIES

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