Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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340 FXUS61 KCLE 050841 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 441 AM EDT Fri Jul 5 2024 .SYNOPSIS... Low pressure entering the Great Lakes region will extend a cold front across the area tonight. The low will depart northeast into eastern Canada for Saturday and high pressure will enter behind the system for Saturday night. High pressure will remain influential across the region through Monday. && .NEAR TERM /THROUGH SATURDAY/... The forecast for today and tonight is a fairly low confidence convective forecast with the overall trend being a lower chance for overall shower and storm coverage and, in turn, a fairly minor threat for strong to severe storms. Clouds and fog remain across the region this morning in the wake of generally widespread rain on Thursday and Thursday night. Some clearing in Northwest Ohio has allowed temperatures to fall a bit from the rest of the region into the low-to-mid 60s. Across the area, dew points remain high in the mid-to-upper 60s, except in cooler Northwest Ohio. Looking elsewhere, a line of storms near the cold front over northern Illinois and southern Wisconsin will curl up into Michigan. South of there, a storm complex marches across eastern Missouri into southern Illinois. This feature should continue east for today, generally along and south of the Ohio River into the central/southern Appalachians. This complex will be key for our area today as the convective debris clouds advecting northeast toward the area will limit temperatures and the system could rob the area of just enough moisture to keep things more tame. By mid-to-late morning, expecting mid-level clouds to be the main feature in the forecast area. Some drier air will advect from the northeast and dew points could actually drop into the mid 60s. The cold front will be near the Ohio/Indiana border by mid-afternoon and the question will be how much will the air mass destabilize ahead of this feature. If temperatures are sub-85 F and dew points are sub-70 F, it is going to be fairly difficult to get good storm coverage going well ahead of the front and there could just be some storms immediately with the front. Therefore, have largely capped PoPs at a 50/50 chance but have lowered some areas to just 30 or 40% at best later today. With the area in a favorable location of the upper level jets, there is ample wind shear for storms to organize, if they can get going, and there would be a damaging wind threat. The Day 1 Marginal from SPC remains for the the entire area. The overall window for storms would start in Northwest Ohio around 2 PM and exit east of the forecast area around Midnight with the cold front. Clearing conditions will enter behind the front tonight and temperatures will cool again into the 60s. Surface low pressure remains near the forecast area in southern Ontario on Saturday morning with its supporting upper trough over the Great Lakes region. The surface cold front will be well east of the area by daybreak on Saturday and drier air will be entering the region with dew points trending down toward the lower 60s. While the air mass is a touch drier than today/tonight, the lift across the region should be enough to generate some isolated shower activity and have some 20 PoPs for much of northern Ohio and NW PA. Temperatures will be cooler than normal near 80 degrees. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... Broad mid/upper troughing will stretch from the northern Rockies through the northern and central Great Lakes this weekend through early next week while an extension of the Bermuda ridge extends into the SE CONUS and Mid Atlantic region. This will keep seasonably warm and humid conditions in place, but the worst of the summer heat will stay well to the south. Weak surface ridging centered over the central and southern Great Lakes Saturday night and Sunday will shift into the eastern Great Lakes Monday as a shortwave deepens the broad mid/upper troughing over the northern Plains. This will allow temperatures to warm several degrees Monday compared to Sunday as return southerly flow sets up, but the influence of the gradually departing surface ridging will keep conditions dry from Saturday night all the way through Monday. By Monday night, chances for showers and thunderstorms will gradually increase from west to east as the aforementioned shortwave progresses across the Midwest and the associated surface low lifts into the western Great Lakes. Most of the precip will hold off until the trailing cold front arrives Tuesday, but with moist SW flow deepening ahead of the system, there will be at least spotty shower and thunderstorm activity in NW and north central Ohio Monday night, so chance PoPs look reasonable. Highs in the low/mid 80s Sunday will warm into the upper 80s/low 90s Monday. Lows Saturday night and Sunday night will range from the low/mid 60s, with upper 60s/low 70s Monday night. && .LONG TERM /TUESDAY THROUGH THURSDAY/... Tuesday will be the best chance for rainfall over the next week as the aforementioned mid/upper shortwave progresses through the Great Lakes, with the surface low reaching near Quebec by Tuesday night. This will drag the cold front across the region during the day Tuesday. Timing will likely change slightly between now and then, but synoptic forcing from the right entrance of a 70-90 knot H3 jet streak combined with daytime heating should generate widespread showers and thunderstorms ahead of the front, so kept likely PoPs from the model blend. Too early to pinpoint any severe weather threat, but given the forcing and jet dynamics, there could be strong to severe storms and locally heavy rainfall depending on timing of the front and the amount of instability. This will be monitored as we get closer. Longwave mid/upper troughing will deepen across the Great Lakes and NE CONUS in the wake of the front Tuesday night through Thursday. This will support cooler, less humid conditions along with mainly dry weather, although isolated showers and thunderstorms are possible in the afternoons in response to daytime heating beneath cooler air aloft. Highs in the mid/upper 80s Tuesday will cool into the upper 70s to mid 80s Wednesday and Thursday. && .AVIATION /06Z Friday THROUGH Tuesday/... Overall, there is fairly low confidence in the TAFs early this morning. High amounts of low level moisture remain the region behind several rounds of rain on Thursday. This is allowing for a mixture of fog and stratus across the region. Unfortunately, there is quite a bit of variability with a range of VFR to IFR in conditions this morning. Suspect that conditions will trend down to MVFR to LIFR for most locations; however, some mid-level clouds continue to move through the region and may prevent more significant fog and stratus from developing. There should be some mixing with daybreak and a trend to VFR by late morning. A cold front will approach the region from the west today. The atmosphere could destabilize and allow for showers and storms to develop during the late afternoon hours. However, clouds in the region could mitigate the energy across the area to help sustain widespread storms. Therefore, have some VCSH and VCTS mentions at the TAFs for this afternoon into tonight. However, do not have the confidence to go with any non-VFR restrictions due to the wide range in possibilities for convection this afternoon and evening. The cold front will sweep through tonight and end the rain threat and allow for conditions to trend to VFR with drying conditions. Winds through the period will have variable direction this morning, ahead of the front this afternoon, and then behind the front tonight, but winds should be 10 kt or less. Outlook...Non-VFR possible in showers and thunderstorms Tuesday into Tuesday night. && .MARINE... Quiet conditions are expected on the lake through the next 5 days with a weak pressure gradient keeping winds fairly light, resulting in waves staying below 2 feet most days. Light and variable winds today will turn WSW and increase to 10-15 knots tonight and Saturday. This will build wave heights to 2 to 3 feet in the central and eastern basins, which will be the highest waves of the forecast period. Winds turn W and decrease to 5-10 knots Saturday night before becoming N at 5-10 knots late Sunday and E Sunday night, then swinging around to SE Monday with 5-10 knot speeds continuing. S to SW winds increasing to 10-15 knots are expected Monday night and Tuesday ahead of a cold front. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...Sefcovic NEAR TERM...Sefcovic SHORT TERM...Garuckas LONG TERM...Garuckas AVIATION...Sefcovic MARINE...Garuckas