Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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645 FXUS61 KCLE 061715 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 115 PM EDT Sat Jul 6 2024 .SYNOPSIS... Low pressure over the Central Great Lakes will depart to the northeast today, allowing high pressure to build into the Ohio Valley tonight. High pressure will remain in control through Monday as it moves towards New England. Low pressure will pull a weak cold front east across the area on Tuesday. && .NEAR TERM /THROUGH SUNDAY/... 100 PM... A few isolated showers had developed across NW PA early this afternoon, but have since dissipated. It appears that the chance for any additional showers this afternoon is decreasing as low and mid-level moisture remains limited. Previous Discussion... An upper level trough over the Central Great Lakes this morning will weaken as it lifts northeast into Quebec through tonight. Surface low pressure over Lake Huron will pull a weak cold front across the area this morning. Water vapor imagery shows dry mid-level air ahead of the trough which will overspread the local area today and serve as a limiting factor for showers/convection. The exception may be across Northwest Pennsylvania towards midday where convergence with the front will be enhanced downwind of Lake Erie and may kick off a few showers for inland portions of Erie and Crawford Counties. Elsewhere a scattered to broken cumulus field will develop as low level moisture wraps in behind the front within the broad cyclonic flow. Enough breaks in the clouds are expected for high temperatures to still reach the low 80s for most of northern Ohio and upper 70s in NW Pennsylvania. The front will be more noticeable due to a drop in dewpoints today which will fall from near 70 on Friday to the low 60s this afternoon. Clouds will tend to clear with the loss of daytime heating tonight although scattered clouds may continue off the east end of Lake Erie. Otherwise high pressure will strengthen over the Ohio Valley and maintain dry conditions for Sunday. Seasonal temperatures in the low to mid 80s can be expected. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... The southern Great Lakes region will be largely influence by broad mid/upper troughing stretching from SE Canada into the Plains battling persistent mid/upper ridging over the Mid Atlantic and SE CONUS. This pattern will persist well into next week, keeping seasonably warm and humid conditions in place while allowing the big heat to stay suppressed well to the south. Surface ridging will exit into the eastern Great Lakes Sunday night and Monday allowing for return southerly flow, but its influence will still keep dry conditions areawide. Chances for showers and thunderstorms will start to gradually increase Monday night, and especially Tuesday as a shortwave progresses through the broader mid/upper trough. This shortwave will move through the southern Great Lakes Tuesday into Tuesday night with an accompanying 70-80 knot H3 jet streak supporting a modest surface low crossing the central Great Lakes. This feature will push a cold front into the region Tuesday, but the shortwave is trending less amplified in all deterministic guidance which will likely cause the front to stall nearby as it becomes oriented parallel with the mid/upper flow. This makes timing of the front uncertain, but given the aforementioned jet support and at least moderate instability (MLCAPE 1000-1500 J/Kg) and seasonably high PWATs, expect good potential for convection Tuesday. With all of this in mind, went a little lower on PoPs Tuesday but still in the high chance range. A few strong to severe storms are possible Tuesday afternoon and evening given the jet support likely yielding at least moderate deep layer effective shear, but the degree of organization will depend on how much cloud cover is present, outflow boundaries, and the timing in which the front sags into the area. Chances for showers and thunderstorms will continue Tuesday night as the front remains in the region, but coverage should be less with the loss of daytime heating. Highs Monday will warm into the upper 80s/low 90s as warm air advection increases ahead of the front, cooling into the low/mid 80s Tuesday with abundant cloud cover expected. Lows Sunday night will fall into the low/mid 60s, with upper 60s/low 70s expected Monday night and mid/upper 60s Tuesday night. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... Uncertainty really increases in the Wednesday through Friday timeframe regarding the coverage of any showers and thunderstorms. The frontal boundary is likely to remain somewhere between the Ohio Valley and southern Great Lakes as it orients parallel to the west- southwesterly mid/upper flow. This is due to the broad mid/upper longwave trough getting sandwiched between persistent ridging over the Mid Atlantic and SE CONUS and another large ridge over the Rockies. This elongated trough may evolve into a closed low over the Plains by Thursday or Friday which will meander underneath ridging expanding east from the Rockies, but the exact evolution is uncertain. At the same time, this pattern could draw moisture northeastward into the Ohio Valley from the remnants of Beryl which would ultimately result in much higher rain chances late in the week. For now, kept PoPs in the slight chance to chance range Wednesday through Friday, with the highest values during daytime heating, but most areas will likely stay dry. Temperatures will stay seasonably warm and humid with highs in the upper 70s/low 80s Wednesday warming into the low/mid 80s Thursday and mid/upper 80s Friday. Dew points will frequently hover around the mid/upper 60s. && .AVIATION /18Z Saturday THROUGH Thursday/... VFR across the TAF sites early this afternoon with VFR to persist through the TAF period. Ceilings are teetering between sct and bkn, around 4kft, early this afternoon. This is mainly associated with diurnal heating and expect these ceilings to lift to few to even skc following sunset. Diurnal sct to perhaps bkn ceilings around 4kft may develop again by Sunday morning/early afternoon. Winds are generally out of the west early this afternoon, around 10 knots. Winds will decrease to less than 5 knots overnight, remaining light into Sunday. A lake breeze is expected to develop by late Sunday morning/early afternoon at CLE/ERI, shifting winds towards the northwest, 5 to 8 knots. Outlook...Non-VFR possible in scattered showers and thunderstorms Tuesday through Wednesday. Non-VFR may return for Thursday in isolated showers and thunderstorms. && .MARINE... Quiet conditions are expected on the lake over the next 5 days as pressure gradients remain weak. W to SW winds will increase to 10-15 knots today, building 2 to 3 foot waves in the central and eastern basins, but these winds will quickly diminish to 5-10 knots tonight before becoming light and variable by late Sunday. E to SE winds will increase to 5-10 knots Sunday night and Monday before turning SW at 10-15 knots by Tuesday then N at 10-15 knots by Wednesday. The best chance for thunderstorms on the lake is Tuesday as a weak cold front sags into the area, and these could produce locally higher winds and waves in and near any of the thunderstorms. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...KEC NEAR TERM...KEC/Kahn SHORT TERM...Garuckas LONG TERM...Garuckas AVIATION...Kahn MARINE...Garuckas