Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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364 FXUS61 KCLE 011051 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 651 AM EDT Sat Jun 1 2024 .SYNOPSIS... High pressure departs east today, with weak low pressure moving east across the region late tonight and Sunday. High pressure briefly returns Sunday night and Monday before a warm front lifts through Monday evening. The area remains in the warm sector until a cold front crosses Wednesday night or Thursday. && .NEAR TERM /THROUGH SUNDAY/... After one last chillier start early this morning the atmosphere will get the memo that it is now "meteorological summer" and respond accordingly, with a warm and largely dry day on the backside of departing high pressure. A shortwave and weak surface low will be lifting out of the mid-Mississippi Valley today which will cause high clouds to spread in and begin thickening and lowering late this afternoon into this evening. However, rain chances don`t begin ramping up until this evening and tonight. Highs will be near or better than 80 for most. While the shortwave and surface low are not anything to write home about from a meteorological perspective, they will bring enough forcing for ascent that when combined with a seasonably moist airmass much of the area can expect showers tonight into Sunday. POPs ramp up from the west starting this evening. Dry low-levels in place ahead of the rain may eat away at the front edge just a bit and slowed down the onset of POPs a bit from the prior forecast. Regardless, by early Sunday showers should have spread into most of our Ohio counties and will be spreading into Northwest PA. A modest slowing trend continues with this system and the whole area will be ahead of the shortwave trough axis and weak surface low early Sunday, which is where forcing will generally be maximized in a warm/moist advection regime. Given this, notably increased POPs area-wide for Sunday morning. The shortwave trough axis should cross the OH/PA boarder early to mid-afternoon on Sunday with shower coverage decreasing behind that trough axis. Held on to "likely" shower wording in far Northeast OH and Northwest PA into early Sunday afternoon. Behind the shortwave trough axis POPs do decrease quite a bit, though modest heating of a moist airmass combined with broad convergence in the vicinity of remnant surface low will likely support isolated to scattered shower re-development Sunday afternoon. Given this, increased POPs some to keep at least a 20-30% type mention in everywhere until Sunday evening. All in all Sunday will not be a true washout of a day but it looks showery area-wide out of the gate with fairly numerous showers not exiting our eastern counties until some point in the afternoon. At least isolated pop-up activity remains possible in the afternoon behind the main batch of showers. Area-average rain amounts of 0.10-0.30" are anticipated with no concern for flooding. Thunder is appearing unlikely as overall instability will be quite limited, though did leave a slight thunder mention in across the southwest Sunday afternoon. Lows tonight generally remain in the low to mid 60s with a few spots out east slipping into the 50s. Highs on Sunday have been lowered a bit, ranging from the upper 60s to mid 70s. Light winds through the period. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... A ridge of high pressure builds in Sunday night, with cloud cover gradually dissipating from the west. Decreasing cloud cover, nearly calm conditions, and residual low-level moisture should result in some patch fog and low clouds late Sunday night into Monday morning, particularly low-lying areas along and east of I-71. This surface ridge gradually departs eastward to the east coast Monday and Monday night. Southerly flow brings temps in the upper 70s and low 80s on Monday and to the mid 80s by Tuesday, with moisture advection bringing dew points into the low 60s by Tuesday. Precipitation chances gradually increase from west to east, with isolated to scattered rain showers and thunderstorms to develop, mainly during the afternoon on Tuesday when there is likely to be some marginal uncapped instability (around 1000 J/kg or less). Currently have PoPs around 30-50% (higher out west such as Northwest Ohio, lower out east such as Northeast Ohio and Northwest Pennsylvania). However, some models have a weak shortwave moving northeast across the area on Tuesday, so it`s possible PoPs could increase if this shortwave can provide forcing for a more focused area of convection. Either way, any rain that occurs is likely to be short-lived, with most of the day being precipitation-free. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... An upper-level negatively-tilted low builds in from the northwest on Wednesday, with the trough axis likely extending southeastward across the upper Midwest and mid-Mississippi Valley at the start of the long term period. A surface low (likely occluded) will be located way back along the Quebec/Manitoba border in Canada, though a cold front will bisect the CONUS, extending across much of the Mississippi Valley to our west. We`ll likely be within the warm sector and Wednesday will be our best best for modest instability as dew points are expected to rise into the upper 60s. This cold front and upper-trough axis should provide sufficient forcing for ascent and with modest instability forecast, have raise PoPs so that the entire forecast area has a period of 70-80% chance of precipitation. It won`t necessarily be an all-day washout (in fact, most of the day will probably be rain-free) but synoptic-scale forcing is increasing confidence in a solid period of showers and thunderstorms some time between Wednesday afternoon through early Wednesday night. There is a low chance of severe weather with this activity, which is really dependent on the evolution of the upper-level trough. Some models have the best mid-level flow (and thus deep-layer shear) lagging behind, which would inhibit severe convection. Latest CSU-ML available to us (00Z/31) only shows a 5% chance of severe weather. The upper-level low continues to build in, likely encompassing much of the Great Lakes region Thursday through Friday. This will likely bring cooler temperatures (near normal on Thursday, below normal on Friday), with scattered rain showers and afternoon isolated thunderstorms. && .AVIATION /12Z Saturday THROUGH Wednesday/... VFR through the day today. A weak area of low pressure will spread showers in from the west starting late this evening and through tonight. By 12z Sunday, expect all to be raining except for ERI and perhaps YNG. Dry low-levels ahead of the rain will likely result in ceilings only slowly lowering. Expect some non- VFR by later tonight into early Sunday due to lower ceilings and perhaps some periods of reduced visibility in steadier rain. Some guidance suggests fairly widespread IFR spreading as far east at CLE and CAK by 12z Sunday...experience says this is likely overdone. Did go with IFR at TOL late in the TAF period, though based on HRRR ceiling forecasts (which tend to be correctly optimistic in these scenarios) kept all other sites MVFR or VFR through 12z Sunday with this update. Winds will shift out of the south-southeast and increase to 6 to 12 knots today. A lake breeze will likely flip winds onshore for a few hours at ERI this afternoon. Currently think the lake breeze won`t quite reach CLE though it will be close. Light south-southeast winds continue tonight. Outlook...Some non-VFR continues into Sunday morning due to showers and lower ceilings before gradual improvement Sunday afternoon and evening. Thunderstorms and associated non-VFR possible at times Tuesday and Wednesday. && .MARINE... Conditions are expected to remain quiet with no marine headlines expected through at least the next few days. High pressure departs to the east coast today before a weak low moves to the vicinity of Lake Erie tonight and Sunday, dissipating and filling in as it does so. This low is replaced by a high pressure ridge that builds across the Great Lakes region Sunday night and Monday before it departs to the east coast. Southwest to southeast flow will be the prevailing winds Tuesday through Wednesday, with a low chance for near 20 knot winds on Wednesday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...Sullivan NEAR TERM...Sullivan SHORT TERM...Saunders LONG TERM...Saunders AVIATION...Sullivan MARINE...Saunders