580 FXUS61 KCLE 192322 AFDCLE AREA FORECAST DISCUSSION National Weather Service Cleveland OH 722 PM EDT Fri Apr 19 2019 .SYNOPSIS... Low pressure over Tennessee will move north along a stalled frontal boundary overnight and weaken over Ohio on Saturday. The low will depart to the northeast Saturday night with a ridge expanding overhead on Sunday. Low pressure will track northeast out of the Plains across the Great Lakes Monday into Tuesday. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Swath of rain from Long Point to Cleveland to Marion will slowly pivot northwest and decrease in coverage through the evening. The decrease in the rain will only be temporary as the next area of lift moves from southeast Ohio into the CWA after midnight. So after the lull where we may still see areas of drizzle we expect to see the moderate rainfall increase. This will also pivot slowly to the northwest through Saturday morning with some instability potentially drifting as far west as an Ashtabula to Millersburg line Saturday afternoon. While thunder chances do not look all that high we do think it warrants an isolated mention in the forecast grids. Previous Discussion... Low pressure is located over eastern Tennessee this afternoon and will move north tonight along a stalled frontal boundary extending across eastern Ohio and western Pennsylvania. Showers have been ongoing today and will increase tonight as a corridor of deeper moisture wraps westward into the area as the upper level low closes off and curls north towards the Ohio Valley. A widespread area of showers can be seen approaching eastern portions of the area with the heavier rain focused in the east during the first half of the night. After midnight another wave of rain will wrap north as a deformation axis and upper level divergence set up across northwest Ohio. This axis will shift west of the area Saturday afternoon but scattered to numerous diurnally driven showers are expected with the upper low overhead. Most of the area can expect to see around an inch of rain through Saturday afternoon with rises expected on area rivers. A few to several will likely experience minor flooding over the weekend. In addition, north to northeast winds will increase on Lake Erie tonight to 25 to 30 knots causing water to pile up on the western basin of Lake Erie. This is not as much of a classic set up with more of a northerly wind component, but given the recent high water levels, models indicate water levels on Lake Erie will approach flood stage overnight. Have issued a Lakeshore Flood Watch from Erie County, OH to Lucas County through 4 PM Saturday. Water levels are expected to peak lake tonight then slowly recede on Saturday. Warmer air will wrap back westward on Saturday with temperatures climbing to near 60 in the east while areas downwind of Lake Erie in NW Ohio remain in the mid 40s. Low pressure will fill on Saturday then depart across the eastern Great Lakes Saturday night. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The short term begins Sunday with models showing stacked low pressure anywhere from western PA to WV depending on the model. An upper ridge is shows building into the midwestern states. Through the day the upper low will drift slowly east as the upper ridge tries to build toward western Ohio. In the morning 850mb temps will be close to 0C over the lake and into nern OH and nwrn PA. Given this, combined with ample synoptic moisture in place, believe there will be ongoing scattered showers off the lake and into the area to start the day. As the upper ridge builds, moisture will decrease so will tapper pops in the afternoon. Will hold onto a slight chance pop across nwrn PA Sunday night but for the most part, the upper ridge will begin to dominate the area. Monday the upper ridge will be across the area and the airmass will be fairly dry. In the afternoon however, models show li's drop below zero in the far west with capes approaching 1400 j/kg in the toledo area. Main concern will be for afternoon/evening convection there so will have a chance pop far northwest. Tuesday weak low pressure will move across the lower lakes throwing moisture back into the area from the north. Will need to have chance pops Monday night for showers. Will go with chance to likely for Tuesday and add thunder as LI's drop to around -5C for the afternoon. Highs Sunday 50s east to 60 to 65 elsewhere. Monday 70 to 75 away from the lake. Tuesday roughly 65 to 70. && .LONG TERM /TUESDAY THROUGH FRIDAY/... For the long term, models are trending toward building high pressure from the northwest however timing differs between the ECMWF and GFS. Have followed the ECMWF closer which has a surface low over Maine with an upper trough axis in NY. High pressure and dry air will be building into the forecast area. The GFS is further west with the low with lingering moisture across the region. The ECMWF continue to build the high into the area through Thursday. Friday low pressure moves through the lower Mississippi Valley throwing moisture north into the lower Ohio Valley ahead of it. At this point, the best moisture will remain south of the region so will continue with a dry forecast for Friday. Highs 55 to 65 Wednesday, in the 60s Thursday and 65 to 70 Friday. && .AVIATION /00Z Saturday THROUGH Wednesday/... MVFR conditions were occurring across NW Ohio this evening but we do expect this region will join in with the IFR conditions that are occurring across the remainder of the region through the evening. Main swatch of rain from Long Point to Cleveland to Marion will gradually pivot westward through the evening and decrease in coverage. However there will likely still be some drizzle even where the steady rains do end. The next area of lift will pivot northward across the region after midnight with the showers returning. As low pressure approaches from the south overnight expect north to northeast winds to increase. The strongest winds will generally be near and west of a KCLE to K4I3 line. Gusts may reach 35 knots in this area. AS the low moves into northern Ohio on Saturday winds will shift to the south for a few hours. The southerly winds look as if they will remain under 12 knots. OUTLOOK...Non-VFR conditions may linger into Sunday morning in fog. A few showers may linger across NW PA. Non-VFR conditions also possible Tuesday into early Wednesday with scattered showers and thunderstorms. && .MARINE... Will continue with the small craft advisory as is. Winds were basically out of the north to northwest on the western two thirds of the lake at 15 to 25 knots. Expect winds to veer to northeast (more central and east) and increase to 30 knots overnight while the western basin remains north-northeast at similar speeds. Main concern is the need for a lakeshore flood watch/warning. The lake level forecast does take the western basin to 72 inches briefly overnight but in addition to that, strong northeast flow will raise levels from Erie County Ohio into the Sandusky bay area that could present problems especially with the addition of 8+ foot waves. So for now will issue a coastal flood watch and will monitor levels and flooding. Winds drop off Saturday afternoon/evening as the surface low weakens. Weak high pressure will build in from the south on Sunday. Winds will remain 15 knots or less through the balance of the forecast. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Lakeshore Flood Watch through Saturday afternoon for OHZ003- 007>009. PA...None. MARINE...Small Craft Advisory until 10 AM EDT Saturday for LEZ142-143- 148-149. Small Craft Advisory until 4 PM EDT Saturday for LEZ144>147. && $$ SYNOPSIS...KEC NEAR TERM...KEC/MM SHORT TERM...TK LONG TERM...TK AVIATION...MM MARINE...