339 FXUS61 KCLE 251338 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 938 AM EDT Sat Jul 25 2020 .SYNOPSIS... Upper level trough continues to push east into New England today while a building ridge extends from the plains into Ontario. At the surface the center of the surface high pressure will drift more central over Ohio today into tonight, before sliding south Sunday into Monday. A slow moving cold front will dip south and cross the area Monday night. && .NEAR TERM /THROUGH TONIGHT/... Latest satellite imagery and observations still showing some patchy dense fog that is quickly dissipating over the eastern portions of the forecast area. Otherwise, fair weather is the rule across the rest of the area. No major changes with this update. Previous Discussion... Look for morning valley fog and stratus mainly in eastern counties, which should burn off with daytime heating. With high pressure becoming more centered over the area today into tonight we will once again see light and variable winds, apart from the anticipated lake breeze. With the upper level ridge axis still west, temperatures aloft are only projected to warm a degree or two today which will translate to temperatures this afternoon mid to upper 80s. Skies will be mostly sunny apart from some diurnal cumulus clouds mainly this afternoon. The airmass will remain fairly dry with PWATs around 1", and surface dewpoints in the low to mid 60s in most areas. The upstream ridge axis will build down into the upper lakes overnight. Meanwhile the surface high shifts south Sunday supporting return flow of low level moisture. Looking for mainly sunny skies save for some daytime heating cumulus. There is some hint at moisture convergence in the afternoon, but with warming temps aloft a cap should block any shower development. Temperatures will continue to warm with highs around 90 to lower 90s across the area. Heat index values will not be much higher than apparent temperatures as the best low level moisture advection comes Sunday night into Monday. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... Sunday night will remain dry with high pressure to the east of the region. Overnight temperatures will remain warm into the 70s with clouds trying to enter the region ahead of a cold front and after highs on Sunday reaching the 90s. The rest of the short term forecast period appears fairly active as an upper trough enters the region from the northwest, supporting a surface cold front. This front will approach the forecast area on Monday and be the forcing for showers and thunderstorms across the area. While the severe threat is non-zero with plenty of instability expected over the region and some shear promoted by this upper trough, the main concern will be the potential for thunderstorms with heavy rainfall. Moisture will be advecting into the region ahead of the front and precipitable water values of 1.5 to 2 inches is expected over the region on Monday afternoon into Monday night. In addition, the front appears to be slowing a bit over the region in the latest model trends and shower and thunderstorm activity may persist for some time over the region on Monday into early Tuesday. Therefore, Monday and Monday night will need to be monitored for active weather, specifically the heavy rain and localized flooding threat. The front will pass through the region on Tuesday and some residual showers and storms will be present until the front clears by Tuesday afternoon. Temperatures on Tuesday will be 5 to 10 degrees cooler than Monday in the lower 80s. High pressure will build in on Tuesday night and the area should be dry, entering the middle of the week. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... The long term forecast period appears fairly quiet at this time. The upper trough that supported the cold front on Monday and Tuesday will propagate eastward out of the region and a northwest flow regime aloft will settle in as a ridge attempts to build to the west. At the surface, high pressure will build into the Great Lakes region on Wednesday and provide mostly dry conditions to the region. Towards the end of the week, the extended guidance begins to greatly differ as the GFS is having issues with convective feedback over the central CONUS. Will opt for a drier forecast with some some of upper ridge building over the region and residual high pressure at the surface. Temperatures through the period appear seasonable at this point in the 80s. && .AVIATION /12Z Saturday THROUGH Wednesday/... Valley fog most notable in the Grand and Mahoning River basins impacting the YNG airport. With daytime heating expect morning fog to lift and burn off by mid morning as a brief stratus deck. For the rest of the terminals VFR conditions will continue with high pressure in control over the area. Some daytime heating cumulus are possible with decks around 5k feet this afternoon. The flow is out of the north, with speeds 5kt or less through the TAF period. Outlook...Non-VFR possible with scattered showers and thunderstorms Sunday night through Tuesday and again Wednesday afternoon. && .MARINE... No marine weather issues are expected through the weekend as high pressure continues to remain influential over the Great Lakes region. Light and variable flow will remain over the lake today with perhaps a push of onshore flow during the afternoon hours with a lake breeze. High pressure wobbles to the east on Sunday and a southwest wind direction on the lake will be favored but winds should be no more than 10 knots. The pattern changes on Monday as a cold front approaches from the northwest and will bring showers and thunderstorms to the region on Monday afternoon and night. Local increases in winds and waves can be expected with any convective activity. The front passes over the lake on Monday night and winds will become northwest for Tuesday. Onshore flow will allow for some increase in waves but at this point, should be below any headline criteria. High pressure builds in Tuesday night into Wednesday and winds will become lighter and more westerly for the middle of the week. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Jamison NEAR TERM...Jamison/Lombardy SHORT TERM...Sefcovic LONG TERM...Sefcovic AVIATION...Jamison MARINE...Sefcovic