Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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118 FXUS61 KCLE 200756 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 356 AM EDT Thu Jun 20 2024 .SYNOPSIS... An upper ridge over the eastern United States will retrograde west through the end of the week. A low pressure system will develop over the upper Midwest on Saturday and move through the Great Lakes on Sunday, extending a cold front across the area. && .NEAR TERM /THROUGH FRIDAY/... An upper level high south and east of the forecast area will continue to allow for similar weather conditions to the past several days: above normal temperatures with hazardous heat impacts and scattered showers and storms with some strong to severe potential. Several days of repeated rounds of showers and storms has allowed for plenty of clouds rolling throughout the region which have helped keep overnight temperatures elevated, but also have allowed each day start a bit slower with slightly inhibited insolation keeping the temperature trends down a bit before eventually reaching the 90s across the area. Will keep this pattern going for the near term forecast with 90s achieved on Thursday and Friday and dew points in the upper 60s to lower 70s allowing for heat index values near 100. The best shower and storm chances appear to be in Northwest Ohio and Northwest Pennsylvania this afternoon. For Northwest Ohio, the best area of deep moist convergence will be into the I-75 corridor and this area has the best chance at meeting convective temperatures, so will have up to a 50/50 PoP in this region. For NW PA, there is a boundary from convection this morning that will lace from western NY into interior NE OH. This could be a source region for storms, especially if there is any form of a lake breeze to enhance this area. The rest of northern Ohio is a bit of a no man`s land for shower and storm development and it would be impossible to get convection in this area, but the chances are lower and are reflected with a PoP closer to 30%. For tonight, the loss of diurnal heating should stabilize things and keep rain chances very low and most folks should stay dry. For Friday, it is tough to be too specific with rain chances but the best region could end up being interior NE OH, depending on how boundaries set up after today`s showers and storms. Any storm could reach strong or severe limits given the instability of this abnormally warm air mass - Wind would be the most common threat. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... Have extended the Heat Advisory an additional day through Saturday as temperatures rebound back into the mid to upper 90s ahead of an approaching low pressure system across the Upper Great lakes. Mainly isolated showers and thunderstorms will be possible once again Saturday afternoon, although could see more "scattered" coverage across the eastern half of the area. Modest SBCAPE of 1500 to 2000 J/kg will be present in addition to large theta-e differences. Will be dealing with the potential for isolated downburst winds once again with any stronger storms. The better potential for more organized strong thunderstorms will arrive on Sunday as an upper-level low moves east across the Upper Great Lakes, extending a surface cold front through the area. The better organized thunderstorm potential appears to be associated just ahead of the front Sunday afternoon, on the tail of an exiting mid-level jet, characterized by modest southwesterly flow of 30 to 35 knots. Damaging wind gusts will be the primary threat from any stronger storms, although could see a low-end tornado risk as well with 0-1 SRH around 100 m2/s2. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... Drier and more seasonable weather will arrive on Monday behind the cold front, with temperatures in the low to mid-80s. Unfortunately, the respite from the heat appears brief as another upper-level ridge begins to build across the Central CONUS. Above-normal temperatures will return on Tuesday with highs in the upper 80s to lower 90s, albeit without the oppressive humidity. By Wednesday, models are beginning to show the evolution of an upper-level trough traversing east through the Great Lakes, extending a cold front south across the area. Thunderstorms do appear likely at some point late Tuesday night through Wednesday night, although confidence remains low on timing and strength of the trough. Behind the front, high pressure will build across the Great Lakes, ushering in drier and more seasonable weather once again into the area. && .AVIATION /06Z Thursday THROUGH Monday/... Showers and storms persist across Lake Erie this morning with a trajectory just north of KERI. Still worth a brief VCTS mention, but impacts at the terminal seem minimal outside of any brief wind shift with an orphaned outflow boundary. High clouds remain across the region from Wednesday`s convection and will continue into the morning hours today. New diurnal cumulus will form during the early afternoon hours, starting in NW OH and NW PA, eventually expanding across the rest of northern Ohio. There will be new afternoon storm chances later Thursday afternoon and have some VCTS mentions at KYNG, KTOL, and KFDY to highlight scattered TS in those corners of the airspace. However, confidence in location and coverage are still fairly limited. TS chances and diurnal cumulus will wane during the evening hours. Winds will be very light through the period with variable direction. Southerly flow will be favored through daybreak before westerly winds begin inland and more northerly flow becomes more favored off a modified lake breeze in the northern terminals. Outlook...Isolated to scattered thunderstorms and non-VFR conditions are possible again Friday afternoon. More organized thunderstorms with non-VFR conditions possible Sunday afternoon. && .MARINE... A generally quiet marine forecast is in store for Lake Erie as a large upper-level ridge remains across the Eastern CONUS, resulting in limited surface flow. Only concern will be in the afternoon and early evening hours through Sunday as daily isolated to scattered thunderstorms could produce strong wind gusts. Thunderstorms may be more widespread on Sunday ahead of an approaching cold front. Will need to monitor wind and wave trends towards the end of the weekend and into early next week as a cold front moves east across the area on Sunday. Ahead of the front, southwest winds of 15 to 20 knots are possible, shifting towards the northwest behind the front on Monday, 10 to 15 knots. && .CLIMATE... A prolonged stretch of hot weather is expected this week. Temperatures are forecast to approach or exceed record highs on several days. The records for Thursday, June 19 to Sunday, June 23 are listed below for our official climate sites. Date Toledo Mansfield Cleveland Akron Youngstown Erie 06-20 98(1953) 94(1988) 96(1988) 95(1933) 95(1933) 92(2016) 06-21 100(2022) 96(1988) 95(2022) 97(1933) 98(1933) 95(1933) 06-22 99(1988) 95(1988) 98(1988) 97(1988) 97(1933) 94(1988) 06-23 96(1911) 91(1964) 94(1948) 94(1923) 94(1943) 92(1964) && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Heat Advisory until 8 PM EDT Saturday for OHZ003-006>014- 017>023-027>033-036>038-047-089. PA...Heat Advisory until 8 PM EDT Saturday for PAZ001>003. NY...None. MARINE...None. && $$ SYNOPSIS...Sefcovic NEAR TERM...Sefcovic SHORT TERM...Kahn LONG TERM...Kahn AVIATION...Sefcovic MARINE...Kahn CLIMATE...CLE