229 FXUS61 KCLE 021038 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 638 AM EDT Thu Jul 2 2020 .SYNOPSIS... High pressure will remain in control across the region today through Friday. A weak cold front will move south towards the area Friday night, but should remain north of the area with high pressure returning through early next week. && .NEAR TERM /THROUGH FRIDAY/... High pressure will continue to dominate the area today through Friday. Some diurnal cumulus expected today, otherwise mostly sunny skies are expected, with mainly clear skies tonight. A weakening mid level trough will sink south across the Great Lakes Friday afternoon, which in combination with modestly unstable conditions could be enough to spark a few isolated showers/storms across the local area. Have opted for low slight chance pops across the area during the afternoon hours. Highs today will be in the upper 80s to low 90s across much of the area. Highs Friday could be a degree or two warmer across the board, contingent on any precip/cloud cover. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... Continued heat will be the focus of the forecast through the holiday weekend. The forecast area will reside downstream of a high amplitude upper level ridge over the Plains and Upper Midwest. A shortwave will round ridge Friday night but expecting any thunderstorms that develop to dissipate by evening as we lose diurnal support. The passage of this trough will allow temperatures on Saturday to drop back 2 to 3 degrees into the upper 80s across far NE Ohio and NW Pennsylvania while inland areas remain at or above 90 degrees. The airmass will be relatively dry with dewpoints mixing down to near 60 degrees in the afternoon so heat index values will mirror temperatures. Temperatures start to creep up on Sunday with nearly all areas in the 90s and mid 90s possible in NW Ohio. Overnight lows will also see an upward trend, with some areas only dropping to the low 70s on Sunday night. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... A prolonged stretch of above normal temperatures will continue through the extended forecast. The upper ridge axis nudges eastward over the Great Lakes on Monday and Tuesday which may prove to be the hottest days before moisture and chances of showers and thunderstorms increase by midweek. Portions of the area will see several consecutive days with highs in the mid 90s and low temperatures continuing to creep up as the heat persists. Although heat index values are not forecast to reach advisory levels at this time, the prolonged duration of the heat, dry conditions, and ample sun will begin to take a toll, especially on sensitive groups. Moisture will begin to creep back up Tuesday into Wednesday and we start to see a chance of showers and thunderstorms return to the area. It is unclear when the ridge will finally break down, but could see enough energy at least round the ridge Tuesday night and Wednesday to warrant a chance of thunderstorms in the forecast. Temperatures will eventually trend down a degree or two but the added humidity will maintain similar heat index values. It is worth noting during this stretch, the GFS appears to be an outlier with 850 temperatures averaging about 4C cooler than the Canadian/ECMWF. Given the building heat over the Plains and dry airmass, preference lies towards the warmer ECMWF MOS temperature forecast. && .AVIATION /12Z Thursday THROUGH Monday/... VFR conditions expected through the period as high pressure continues over the region. Some diurnal cu may impact terminals during the day, but otherwise skies will be clear. Lighter and more variable winds will increase out of the north to northwest through the day, up to 10 kts at some terminals, decreasing again tonight. Outlook...VFR. && .MARINE... Although high pressure will generally remain in control of the weather, a series of weak troughs will slide south across the eastern Great Lakes through Friday. Lake breezes will develop on the central and western Lake Erie today while westerly winds increase to near 15 knots on the east end of the lake for a few hours this evening. Both the fetch and duration not expected to be long enough for a Small Craft Advisory, but choppy conditions with 2 to 4 foot waves can be expected for a few hours in the PA waters. For the holiday weekend, land and lake breeze circulations expected to persist with speeds of 15 knots or less. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Greenawalt NEAR TERM...Greenawalt SHORT TERM...KEC LONG TERM...KEC AVIATION...Greenawalt MARINE...KEC