Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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635 FXUS61 KCLE 190519 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 119 AM EDT Fri Jul 19 2024 .SYNOPSIS... A ridge continues to affect northern Ohio and northwest Pennsylvania through Friday as the parent high pressure center moves from the Upper Mississippi Valley to the Lake Erie region. The high pressure center is then expected to move little this weekend and allow the ridge to continue to affect our region. && .NEAR TERM /THROUGH TODAY/... 900 PM Update... Clouds have diminished and expect mostly clear to clear skies for the rest of the night. Can`t rule out patchy valley and/or radiational fog in southeastern zones early Friday morning. No changes were needed with this update outside of small adjustments to hourly temperatures and dew points based on latest observations and forecast trends. Previous Discussion... Cyclonic flow aloft, varying between SW`erly and NW`erly, and embedded shortwave disturbances affect our region through Friday night. At the surface, a ridge associated with an unusually- cool and less-humid air mass continues to affect our region as the center of the ridge drifts from the Upper MS Valley toward Lake Erie and weakens. Fair weather is expected to persist as a stabilizing subsidence inversion accompanies the low-level ridge. Overnight lows are expected to reach mainly the 50`s to lower 60`s around daybreak Friday morning and Saturday morning, respectively, as mainly clear to partly cloudy sky, weak or calm surface winds, and surface dew points mainly near 50F to 55F promote efficient radiational cooling during evening hours through daybreak. The warmest lows are expected over/very near ~76F Lake Erie. Localized river valley steam fog is expected and patchy radiation fog is possible around daybreak both mornings, especially in interior NW PA and NE OH. Any fog will dissipate soon after daybreak via the onset of diurnal heating/convective mixing of the boundary layer tapping into drier air aloft. On Friday, late afternoon highs are expected to reach the mid 70`s to 80F as diurnal convective mixing of the boundary layer occurs amidst 850 mb temperatures near 11C to 12C. Despite a very marginal temperature contrast between relatively-warm surface air over surrounding land and Lake Erie, a very weak synoptic MSLP gradient and the anticyclonic circulation of the synoptic surface high pressure center settling over the lake are still expected to allow a lake breeze to occur Friday afternoon through early evening. The N`erly synoptic MSLP gradient in most of our CWA will allow the lake breeze to have significant inland extent, especially from roughly the longitude of the Lake Erie Islands and points farther east. This has been a consistent signal in the last few runs of the HRRR and other mesoscale NWP models. The coolest highs on Friday are expected over/within a couple miles of Lake Erie. && .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... The weekend forecast appears quiet for the local area. A weak upper low to the west over Minnesota and Iowa will block an upper trough moving through eastern Canada from overtaking the Great Lakes region. This will actually allow for some upper ridging to form over the local area and keep high pressure in place across the region. With that, will keep the forecast dry with relatively seasonable temperatures with 80s for highs. Lows on Saturday night could continue to be a bit cool with mid 50s under clear conditions. Lows should recover somewhat for Sunday into the 60s. && .LONG TERM /MONDAY THROUGH THURSDAY/... After a weekend reprieve of weather, the forecast for next week returns to conditional shower/storm chances before a bonafide weather system will approach the area for the middle of the week. For Monday, the weak upper low over the Midwest will open up and the energy will push east toward the Great Lakes region. A warmer air mass with temperatures in the mid to upper 80s should be in place to generate some instability to help diurnally force convection. However, moisture in the region will be fairly limited and will be the main factor to prevent much from happening. With the western low gone, a larger upper trough will swing into the Great Lakes region on Tuesday and Wednesday. This system will bring a more formal low pressure system with a cold front through the area, which should force more widespread shower and storm chances and have PoPs to likely levels. A stronger upper wave of the trough will move through on Thursday and allow even better support for showers and storms on Thursday. However, several rounds of rain and lingering clouds could make Thursday more conditional thermodynamically, but will keep some likely PoPs in the forecast for now. Overall, Tuesday through Thursday will be a period to watch for shower and storm chances and potential summer weather hazards. && .AVIATION /06Z Friday THROUGH Tuesday/... VFR. High pressure. Winds light and variable/light northerly less than 10kts. Outlook...VFR expected through Monday morning. Isolated showers/thunderstorms with non-VFR possible Monday afternoon and evening with better chances for showers and thunderstorms Tuesday. && .MARINE... One final push of a surface trough across the lake tonight will allow for a window of enhanced northerly winds, especially for the central basin of Lake Erie. Waves will marginally respond to 3 ft, but should stay controlled enough to not need a Small Craft Advisory. High pressure will be in control of the Great Lakes region for Friday through Sunday and marine weather should be quiet. Winds will be light, less than 10 kt, and variable through the period, as there will be directional changes with lake and land breezes. Waves will respond by staying 2 ft or less through the period and likely just flat through Sunday. High pressure will move out starting on Monday and a warm front will approach the lake. Winds will shift from the northeast to east during the day and then southeast at night, all at 10 kt or less. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...Jaszka NEAR TERM...Jaszka/Maines SHORT TERM...Sefcovic LONG TERM...Sefcovic AVIATION...26 MARINE...Sefcovic