213 FXUS61 KCLE 021050 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 650 AM EDT Tue Jun 2 2020 .SYNOPSIS... A warm front will lift east across the area this morning. A cold front will move south across the region Wednesday afternoon through early Thursday morning. Another weaker cold front will track east across the area on Friday night. && .NEAR TERM /THROUGH WEDNESDAY/... Most of the shower activity has exited the area with some residual light showers over the eastern basin of Lake Erie headed into NW PA over the next couple of hours. The warm front has just begun to make its way into the western portions of the area this morning and will continue east throughout the day. Some showers have moved across the area early this morning ahead of the approaching warm front, but the activity has remained relatively light, given large dewpoint depressions and dry air aloft. Warm air advection really ramps up today following the frontal passage, with southwest flow and dry low and mid level air contributing to mostly sunny skies, especially across NW OH. It will also feel noticeably more muggy with dew points in the 60s. It's likely that temperatures will exceed guidance by at least a few degrees, so have gone slightly warmer, especially across NW OH. Afternoon highs will reach the upper 80s to perhaps low 90s, while cooler low 80s and even upper 70s will be found across NE OH and NW PA. Warm air advection and higher dew points will allow for temperatures to remain in the low 70s throughout the evening and overnight hours. Attention then turns to late Tuesday night into even perhaps Wednesday morning. Thunderstorm activity across the region during the day today will be unlikely, as warm h850 temps create a strong capping inversion which will inhibit convection. However, a southeastward diving shortwave across southern Ontario will initiate thunderstorms across the Upper Midwest along and just ahead of an associated cold front this afternoon and evening. The expectation is for this area of convection to congeal into a cluster and likely an MCS which will track east across Lake Michigan and southern MI, eventually reaching the vicinity of Lake Erie and the immediate lakeshore by early Wednesday morning. There remains uncertainty about the scale and evolution of this MCS as it approaches Lake Erie, but there will be unusually high nocturnal instability across the region, with MUCAPE near 2000 J/kg and 0 to 3 km SRH of around 100 to 200 m2/s2. This would be sufficient to sustain any convection across the Lake. There also may be some redevelopment of this MCS early Wednesday morning as it reaches Northeast Ohio and Northwest Pennsylvania. This late-night, early morning Wednesday activity is covered by a marginal risk in SPC's day 1 and day 2 outlook. Main hazards look to be damaging wind, although can't rule out an embedded weak tornado. As the cold front moves south across the area, thunderstorm development is expected ahead of the front across the vicinity of north-central Ohio. There is higher confidence in severe storm potential as highlighted by a slight risk in SPC day 2 outlook, though position of this afternoon and evening convection has appeared to slowly migrate south over the past several model runs. The best axis of shear and instability looks to be placed across eastern OH into western PA with MLCAPE reaching 2000 to 3000 J/kg and effective shear of around 40 knots. Main hazards would be damaging wind and large hail up to an inch, though a tornado, especially along the OH/PA border is not out of the question. Heavy rain and flash flooding is also a risk for the activity along and just ahead of the cold front Wednesday afternoon and evening as storm motions will develop and move parallel to the cold front, promoting back-building (storm training). This threat is highlighted in WPC's day 2 excessive rain outlook. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... Thunderstorm activity will diminish from north to south on Wednesday night as the front reaches Central Ohio. The front dissipates near or south of the area but does not scour out low level moisture and instability which will remain across southern areas into Thursday. Shortwave energy moving through the flow aloft will likely result in scattered thunderstorms Thursday afternoon. The airmass remains warm with temperatures generally in the lower 80s Thursday with some areas reaching mid 80s by Friday. Scattered thunderstorms remain a possibility again on Friday as a trough moves into the Upper Great Lakes, with a cold front moving south into the area on Friday night. Forcing is somewhat lacking for convection during the day on Friday but a region of weak low level convergence across NE Ohio may act as the primary focus. The chance for thunderstorms will continue into Friday night with the front. && .LONG TERM /SATURDAY THROUGH MONDAY/... A cooler and drier airmass will arrive for the weekend as the upper level pattern become more amplified with a trough deepening across New England. The weekend will feature a dry forecast with temperatures in the 70s and low humidity. Much warmer temperatures will return early next week as the trough shifts off the east coast and a strong upper ridge builds overhead. The building ridge may bring the warmest air so far this season. && .AVIATION /12Z Tuesday THROUGH Saturday/... VFR conditions across the TAF sites this morning and VFR conditions look to persist through the rest of today. Some light rain showers could be possible at ERI over the next couple of hours, but won't be too impactful. The chance for thunderstorms increases at TAF sites along the lakeshore towards the end of the TAF period (9 to 12Z) so have included mention of vcts at TOL/CLE/ERI. There may be an earlier round of thunderstorms that clips ERI to the north earlier in the night, so started vcts there at 3Z. Winds will gradually increase to 10 to 15 knots later this morning and afternoon with gusts around 20 to 25 knots and shift towards the southwest with the passage of the warm front. Outlook...Non-VFR is possible across the area Wednesday afternoon and evening associated with thunderstorms. Non-VFR may be possible again Wednesday night/Thursday morning associated with patchy fog. && .MARINE... Southwest winds on Lake Erie will ramp up to 15 to 20 knots today as an area of low pressure moves into the Upper Great Lakes. As this low continues east towards New England on Wednesday a cold front will move south across Lake Erie. Thunderstorms are likely late tonight which may be strong and lead to higher winds/waves and a disruption of the forecast conditions through Wednesday. Winds will be light on Thursday then southwesterly on Friday ahead of another cold front that will move south across Lake Erie Friday night. High pressure will strengthen north of the lake over the weekend with north to northeast flow of 5 to 15 knots. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Kahn NEAR TERM...Kahn SHORT TERM...KEC LONG TERM...KEC AVIATION...Kahn MARINE...KEC