420 FXUS61 KCLE 281746 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 146 PM EDT Tue Apr 28 2020 .SYNOPSIS... Low pressure will reach the Upper Midwest today with a warm front slowly lifting north into the area. The warm front will lift north of Lake Erie tonight with unsettled conditions continuing through Thursday as the low slowly moves east across the Great Lakes. High pressure will gradually expand east into the region late Friday into Saturday. && .NEAR TERM /THROUGH WEDNESDAY/... Dry conditions will prevail across most of the area for another few hours before some development of scattered showers along the warm front later this afternoon. Some SHRA already popping just west of the forecast area that may sneak into the I-75 corridor a few hours earlier than the rest of the area. Some instability south of the front could bring a few rumbles of thunder. Otherwise, little change to the overall forecast with the midday update. Previous discussion follows. A warm front will lift north this afternoon into the forecast area but will be met with resistance by east to northeast flow off Lake Erie and have kept temperatures from Toledo to Sandusky a few degrees cooler given the flow off the lake. Scattered showers, perhaps a few rumbles of thunder, will develop this afternoon along the frontal boundary with coverage increasing from Cleveland eastward as the front moves across Lake Erie. Temperatures will be mild tonight as most areas get into the warm sector with breezy southerly winds and temperatures at or above 60 degrees across much of Ohio. On Wednesday strong moisture advection will arrive with widespread showers overspreading the area from west to east. There will be a chance of thunderstorms mainly late Tuesday night into Wednesday morning forced by a 50+ knot low level jet moving north across NW Ohio towards Lake Erie. PW values also increase to 1.25" on Wednesday. The upper level trough becomes elongated, extending south to the Gulf Coast by Wednesday evening. The surface low will occlude over Michigan with the cold front wrapping in from the west late Wednesday. Thunderstorms remain a possibility but considerable low level moisture will limit heating and instability. Rainfall through Wednesday night will range from 0.75-1.15". Temperatures will peak in the upper 60s in NE Ohio and NW PA where showers do not arrive until afternoon. The slow arrival time of the rain and strong south to southeast wind field will create a window of time where downsloping flow will be a concern in NW PA. Winds are expected to strengthen along the Erie PA lakeshore, allowing some of the stronger winds of 45-50 knots at 2000 feet to mix down. The forecast calls for wind gusts to 45 mph in Erie County Pennsylvania and a Wind Advisory may be needed on Wednesday. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... Low pressure over the Great Lakes region will continue its slow march eastward on Wednesday night. The occluded front of the vertically stacked low appears to pass through the region on Wednesday night and much of the rain will push east with the passage of this boundary. Residual moisture and the general forcing of the deep upper trough will allow for rain chances to continue behind the front, but intensity will be limited to very light rain at best. The low pulls northeast on Thursday and extends a cold front across the area by Thursday evening. Rain chances will increase on Thursday ahead of the front, as the center of the upper low moves over the area. Rain intensity still appears light as the deep moisture is pulled away from the region; however, there is high confidence in light rain during the day on Thursday. Behind the cold front, a residual trough of low pressure lingers over Lake Erie for Friday and will be a persistent source for showers over the eastern half of the area. Building high pressure will force this trough feature out of the area on Friday night, drying the area out for the weekend. Temperatures through the period will be well below normal with most areas into just the 50s for highs on Thursday and Friday. && .LONG TERM /SATURDAY THROUGH MONDAY/... The first weekend of May will begin with an upper ridge over the Great Lakes region supporting an area of high pressure over the southeast United States, extending north into the forecast area. A warm air advection regime and a relatively dry airmass should allow for Saturday to be the pick day for the weekend. Dry weather should be in place and temperatures should at least reach normal, if not push higher into the 70s. Have opted for temperatures above most model guidance as the trend has been drier, earlier for Saturday. Sunday has a chance to be a fairly decent weather day as well before the next system enters the forecast area. A shortwave trough flattens the upper ridge on Sunday and allows for a cold front to enter the region. The timing of this front is still somewhat uncertain and a late entry into the forecast area would allow for another warm day for most areas. Once the front enters, rain will be possible on Sunday night into Monday. Temperatures will cool considerably behind the front for the start of the first full week of May and likely persist beyond Monday. && .AVIATION /18Z Tuesday THROUGH Sunday/... VFR/MVFR ceilings at the onset of the period will lift higher into tonight as a warm front lifts north through the terminals. Some -SHRA, and a very low chance for TSRA, possible with the warm front. Dry conditions for most of the area through 12Z before -SHRA and lowering ceilings move east ahead of a cold front through the end of the period. Winds will generally be out of the south through most of the period, increasing ahead of the front with some gusts possible late. Higher gusts expected at KERI with downsloping. Some LLWS possible late tonight, but not confident enough for TAF mention at this point. Outlook...Periods of rain may result in non-VFR conditions through Thursday night. && .MARINE... Low pressure over the upper Missouri River Valley has extended a warm front south of Lake Erie. As this low moves east today, this warm front will be pushed north across the lake tonight. Ahead of the front, flow will be easterly and slightly onshore, shifting to southerly, offshore flow behind the front. The offshore flow may become somewhat stronger over the eastern basin of Lake Erie as downslope flow off the terrain of western NY/NW PA/NE OH will enhance winds and present an opportunity for a brief small craft advisory headline. Low pressure enters the Great Lakes region on Wednesday and will be very slow to move through the region. The occluded front will ripple across the lake on Wednesday night and allow for weaker southerly winds to enter. The low pulls to the northeast on Thursday and will extend an associated cold front across the lake by Thursday evening. Flow will become westerly and onshore with the passage of this feature. A trough of low pressure will linger behind the departing low and set up over the lake. Winds will become more northwesterly and enhance a bit over the basin. Marine weather headlines may be possible for the Thursday night through Friday night time frame. A ridge of high pressure builds from the south on Friday night and will settle over the lake for Saturday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...KEC NEAR TERM...KEC/Greenawalt SHORT TERM...Sefcovic LONG TERM...Sefcovic AVIATION...Greenawalt MARINE...Sefcovic