Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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344 FXUS61 KCLE 230758 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 358 AM EDT Sun Jun 23 2024 .SYNOPSIS... A cold front will move east this afternoon before high pressure builds in for Monday and Tuesday. Another cold front associated with a low pressure over Ontario will move east across the area on Wednesday before high pressure returns for the end of the work week. && .NEAR TERM /THROUGH MONDAY/... Currently, a broad trough aloft is providing support for a surface low pressure to continue to move northeast through the western Great Lakes region. The area currently lingers in the warm sector of the low pressure with temperatures across the area in the 80s and dewpoints lingering in the mid to upper 60s. Looking upstream across northern Indiana, a line of convection continues to track east, gradually weakening in terms of intensity, but still maintaining widespread thunderstorms with gusty winds and lightning. A LLJ of 40- 45 knots has moved across the area resulting in non-convective gusty winds up to 20 knots this morning. This LLJ and mid-level support should be enough to maintain the line of convection, where locally higher gusts are possible. In the heaviest storms, expect very efficient rainfall of over 1"/hr as PWAT values climb over 2" and warm cloud layers deepen to over 13 kft. With this overall limited instability this morning, still expecting a general weakening trend with locally higher wind gusts and heavy rain possible. The trickier part of the forecast is for this afternoon as the aforementioned line of convection exits east of the area late morning. This afternoon, the cold front is expected to push east across the area, stirring up another potential round of scattered convection. Many ingredients, including a moist boundary layer, increasing instability to 1000-1500 J/kg, and a lingering LLJ will couple with strong isentropic ascent along the boundary to provide enough support for additional storms development along and east of I- 71. Primary concern with any storms that develop with be strong damaging winds, although with effective shear values of 20-30 knots isolated large hail cannot be ruled out. In addition to the severe potential, the PWAT values remaining over 2" and deep warm cloud layers will produce heavy rainfall. In areas that received precipitation with the initial round of storms, may see some flooding especially in urban and low lying areas. The biggest question mark with this forecast is in regards to how fast the atmosphere will be able to recover behind the initial round of convection. Widespread clouds are expected today which typically would limit instability and potentially limit convection, but given the strong surface lift and moisture rich environment confidence is low that the clouds will have as strong of an effect. To highlight these threats, SPC has issued a Slight Risk SWO for the far eastern counties and a Marginal Risk SWO for the remainder of the areas along and east of I-71. In addition, WPC has issued a Day 1 Marginal ERO for those far eastern counties. Showers and thunderstorms should primarily dissipate once the cold front pushes east late this evening. A few showers and storms may linger into late evening, but with a northwest flow becoming established across the area, colder 850mb temperatures near 10C will begin to push across Lake Erie and transition the lingering precipitation to primarily be lake enhanced with limited thunder potential. By mid-Monday morning all precipitation should end across the area as high pressure becomes established over the area. High temperatures today and Monday return to more seasonal, climbing into the low 80s for much of the area with the portions of the eastern counties possibly only reaching into the upper 70s. Overnight lows tonight will drop into the low 60s. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... A dry, stable pattern will allow for a pleasant night on Monday with temperatures falling below 60 degrees for a large portion of the forecast area - first time in about 2 weeks! Unfortunately, the remainder of the short term period will feature a more active pattern and return to warmer temperatures and high humidity. Surface high pressure will move east for Tuesday and return flow across the region will allow for temperatures to soar back into the upper 80s to lower 90s and dew points reach the 60s again. A minor shortwave will move through the region on Tuesday and allow for some small shower and storm chances, but the main show appears to be on Wednesday as better synoptic forcing will enter the region with a larger upper trough and surface cold front. Have PoPs increasing to likely and even categorical for Tuesday night into Wednesday. Have come concern about severe weather potential for Wednesday, as the present consensus for the timing of the main synoptic forcing features is Wednesday afternoon and evening, which coincides with peak heating of the day with upper 80s and near 70s dew points that would support a fairly robust thermodynamic environment for storms. This day will be one to watch moving forward. && .LONG TERM /THURSDAY THROUGH SATURDAY/... Thursday should be a repeat of Monday with high pressure entering behind the main synoptic system, allowing for a dry, stable environment with cooler than normal temperatures and pleasant conditions. The surface high will shift east on Friday as the ridge axis enters and return flow once again enters the region with highs achieving the mid to upper 80s again. A shortwave will override the ridge later on Friday into Saturday, followed by a stronger upper trough for the weekend. This will once again contribute to an active pattern with increasing storm potential for the weekend. && .AVIATION /06Z Sunday THROUGH Thursday/... Widespread VFR conditions are being observed across the area this morning ahead of an approaching line of storms being observed in northern IL/IN and southern MI. This line of storms will continue to progress east towards the region this morning, initially impacting KTOL and KFDY between 08-09Z. Within these showers, heavy rainfall will likely reduce visibilities to MVFR distances, possibly IFR in the heaviest showers. There is an overall weakening trend with the line given the diurnally unfavorable environment, but still expected thunder to be heard at most stations through this morning. This initial line will depart east by late morning, but a secondary round of storms is expected along the cold front that move east today. Highest confidence in the storm potential is along and east of I71, although if western counties rebound quick enough cannot rule out a thunderstorm or two for KTOL and KFDY. Confidence in this occurring is limited, so opted to only mention additional thunder at terminals east of those. Quite a bit of uncertainty remains with the strength of convection this afternoon given these morning storms, but any terminal impacted will likely see periods of MVFR and possibly IFR given the heavy rain potential. In addition, MVFR ceilings will push east along the cold front, but should rebound for all terminals around sunset tonight. Southwest winds this morning will ramp up to 10-15 knots, gusting up to 25 knots into the early afternoon. Behind the cold front that moves through, winds will shift to become northwesterly at 10-15 knots with gusts up to 25 knots initially, but are expected to quickly weaken by 00Z Sunday to be 5-10 knots across the area. Outlook...Non-VFR possible in scattered showers and thunderstorms across Northeast Ohio and Northwest Pennsylvania Sunday night into Monday. Additional non-VFR possible in showers and thunderstorms Tuesday evening through Wednesday. && .MARINE... After a rather benign marine weather week, the weather will be more active this week with several windows for marine headlines, several widespread storm chances, and generally increased winds across the lake. For today, southwest flow will increase ahead of a cold front this morning, winds will get close to 20 kt and will have a Small Craft Advisory for the winds starting this morning. The front and convection will cross the region later today and onshore flow will increase wave action, which will allow for a longer period for the Small Craft Advisory and these areas will be the land zones with the Beach Hazards Statement for increased swimming risk with the higher waves. Have tweaked the areas and timing of the marine hazards this morning just slightly to align with the current wind and wave forecasts. High pressure across the region on Monday will allow for decreasing northwest flow during the day, followed by light and variable flow overnight. Return flow on the back side of the high on Tuesday will allow for increasing south to southwest winds and there are some minor chances for showers and storms. A potent cold front will enter for Wednesday and bring widespread showers and storms to the region. Southwest flow will increase ahead of the front to at least 15 kt during the day on Wednesday. Winds will shift to the northwest behind the front on Wednesday night and will increase waves. This window could potentially need a Small Craft, but the forecast remains below at this time. High pressure will return to the region for Thursday and bring decreasing northerly flow. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Beach Hazards Statement from 11 AM EDT this morning through late tonight for OHZ010>012-089. PA...Beach Hazards Statement from 11 AM EDT this morning through late tonight for PAZ001. NY...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for LEZ142>144. Small Craft Advisory from 8 AM this morning to 4 AM EDT Monday for LEZ145>147. Small Craft Advisory from 11 AM this morning to 4 AM EDT Monday for LEZ148-149. && $$ SYNOPSIS...Campbell NEAR TERM...Campbell SHORT TERM...Sefcovic LONG TERM...Sefcovic AVIATION...Campbell MARINE...Sefcovic