Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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595 FXUS61 KCLE 281405 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1005 AM EDT Fri Jun 28 2024 .SYNOPSIS... A warm front will push through and north of the area today. A cold front will approach the area from the west on Saturday and cross the area on Saturday night. High pressure will build from the west for Sunday into Monday. && .NEAR TERM /THROUGH SATURDAY/... 9:30 AM Update... Slightly increased cloud cover this morning into the early afternoon to account for the high and mid-level moisture and associated cloud deck streaming in from the west ahead of the warm front. This will lead to mainly filtered sunshine this afternoon. Otherwise, the rest of the forecast remains on track. Previos Discussion... Returns on the radar this morning are not amounting to much of anything this morning as mid level clouds are moving into our dry forecast area and not much is reaching the surface. Have kept dry PoPs despite returns in NW OH and northern Indiana. Previous Discussion... Today will be a return to normal across the forecast area with a warm front pushing north across the area and return flow coming back to the region. Temperatures will rise back into the 80s and dew points will slowly recover through the day into the low-to- mid 60s by nightfall. High clouds will be floating through the region today and will obscure full sunshine and the full potential of the warm sector and light southeast flow will be present today. A modified lake breeze will impact areas very close to the lakeshore, but believe there is enough of a pressure gradient in place to prevent much inland movement. Unfortunately, the moisture spigot continues through the night and dew points will get rather juicy into the upper 60s and lower 70s by daybreak on Saturday. The strong isentropic lift across the region tonight should allow for showers and thunderstorms to develop through the night with the greatest coverage by daybreak. Also helping shower and storm coverage will be a 45 kt low level jet at 850 mb that will be moving through the region after midnight and could inflame convection across the forecast area. For now, do not believe that convection overnight will be severe as there is not a lot of instability to work with and storms may be elevated. However, these showers and storms may prime the area with an initial round of rain that could have repercussions for Saturday. With warm advection, clouds, and rain in the region, believe that lows will be in the upper 60s to lower 70s with most areas likely staying above 70. The Saturday forecast continues to be a very active weather day across the region with appreciable threats with both severe weather and flash flooding. A strong southwest to northeast oriented 850 mb low level jet with southwest flow parallel to a surface cold front moving southeast will be the main culprits for both threats. For the severe weather threat, the main 850 mb jet will be departing to the northeast by the late afternoon and early evening hours. The right entrance region will be over the eastern half of the forecast area during this time and could offer great support for severe storm development in this region. The wind shear values across the area on Saturday afternoon are rather impressive for late June with 0-6 km bulk shear values of 50 to 55 kt and 0-3 km SRH over 200 m2/s2 in the entrance region of this low level jet. Therefore, storms have a great chance to become organized for all severe weather hazards, especially if some supercell thunderstorms can form. A 5% tornado probability has been introduced in the Day 2 Severe Weather Outlook, as that threat is beginning to look more intriguing with some convective model output showing the sig tor parameter over 1 in the eastern portion of the forecast area. However, there is one big concern for the entire severe weather setup - instability. Showers and storms are likely to be ongoing across the region on Saturday morning and with the low level jet overhead offering support, these will likely persist through the day. Any break in shower and storm activity and especially any breaks in the clouds could spell trouble as there will be opportunity for larger amounts of surface based instability to form in the region. Surface dew points will be trending upward during the day on Saturday into the 70s with the efficient moisture advecting into the region, so it won`t take much warming to get appreciable CAPE. However, instability is the limiting factor for the severe threat and why a Day 2 Slight Risk for severe weather is appropriate at this time. The hail threat on Saturday will also be limited to just supercell development at this time. Wet bulb zero values are at 13k ft and higher and will allow for melting hail (and flooding, more next!) vs. observed severe hail. The Slight Risk now incorporates almost the entire forecast area as there is enough shear to be concerned everywhere. However, the eastern counties have the greatest concern at this time with the highest shear and best chance at getting a late morning break in rain and could be a candidate for future upgrades, depending on convective trends tonight into Saturday. While the severe threat is trending upward across the forecast area, the flash flooding threat is also increasing across the region. Rain late tonight into Saturday will help prime the area with some water to reinvigorate a relatively dry region. Most areas received rain on Wednesday that was quickly absorbed, and this initial round should allow for a few tenths to an inch or so of rain to prime the area ahead of more potent rainfall rates later on Saturday. Coincident with the timing of Saturday`s severe weather threat during the afternoon and evening are also some pretty good parameters for flash flooding in the region, precipitable water values near/above 2 inches will be near/above daily maximums for the region, wet bulb zero values over 13k ft will allow for more melting hail and heavier rainfall in thunderstorms, the southwest flow of the 850 mb jet is parallel to the surface cold front and it will be likely that storms train over the same areas until the storms are pushed out of the area Saturday night with the cold front. With that, QPF has been raised considerably across the entire forecast area, especially the southeast areas, where more convective cores are expected. For these areas, have contours of 2+" of rain in the forecast and it is likely that this will occur quickly, posing a flash flood threat, especially in urban and poor drainage areas. This area is also under a Day 2 Slight Risk for Excessive Rainfall to highlight the flood potential. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... Cyclonic W`erly flow aloft and embedded shortwave disturbances affect our CWA Saturday night as a cold front sweeps SE`ward through northern OH and NW PA. Behind the front, a low-level ridge builds from the north-central U.S. and vicinity. Additional scattered/organized showers and thunderstorms with periods of torrential rainfall are expected along and ahead of the cold front as the warm/very moist sector boundary layer remains weakly to moderately unstable amidst moderate to strong deep layer bulk shear. Given the projected thermodynamic/kinematic environment, strong to severe thunderstorms and localized flash flooding remain a concern beyond sunset. The shower/storm threat will end from northwest to southeast with the passage of the front and fair weather is expected CWA-wide by daybreak Sunday morning as stabilizing subsidence accompanies the building ridge. Low-level CAA behind the front will contribute to lows reaching the 60`s around daybreak Sunday. Fair weather is still expected on Sunday through Monday as the low- level ridge continues to build from the north-central United States and vicinity and is accompanied by stabilizing subsidence and net low-level cold/dry air advection. Simultaneously and farther aloft, cyclonic W`erly to NW`erly flow and embedded shortwave disturbances eventually give way to a ridge building from the Great Plains. Late afternoon highs are expected to reach the upper 60`s to upper 70`s on Sunday and Monday, respectively. Overnight lows should reach the 50`s to lower 60`s around daybreak Monday. Net albeit weak low-level WAA is expected to develop across our CWA Monday night as the core of the low-level ridge begins to exit toward New England and the ridge aloft crests E`ward over/near our CWA. Fair weather persists as stabilizing subsidence continues to affect our region. Overnight lows should once again reach mainly the 50`s to lower 60`s around daybreak Tuesday since partially clear sky, limited low-level humidity, and weak surface winds are expected to promote efficient nocturnal cooling Monday evening through daybreak Tuesday. && .LONG TERM /TUESDAY THROUGH THURSDAY/... Tuesday is still expected to feature fair weather as high pressure at the surface and aloft exits slowly E`ward, yet associated stabilizing subsidence persists over/near the eastern Great Lakes and Upper OH Valley. Continued net WAA along the western flank of the low-level ridge will contribute to late afternoon highs reaching the upper 70`s to lower 80`s in NW PA and the 80`s in northern OH. Cyclonic W`erly flow aloft and embedded shortwave disturbances affect our region Tuesday night through Wednesday night as surface troughing becomes established across northern OH/NW PA. A warm front will sweep N`ward through our region Tuesday night and usher-in a much warmer/more humid air mass originating over the Gulf of Mexico. In addition, a cool front is still expected to sweep generally SE`ward through our region Wednesday night and usher-in a slightly- cooler and less-humid air mass. The lifting mechanisms (i.e. shortwave disturbances/attendant surface trough axes and fronts) are expected to release weak to moderate instability, including elevated instability, to trigger periodic showers/thunderstorms. Moderate deep layer bulk shear will allow convection to be organized. Severe thunderstorms are possible given the projected thermodynamic and kinematic environment. The best chance for severe thunderstorms is expected Wednesday afternoon through early evening, when daytime heating of the warm/moist sector boundary layer will allow MUCAPE to be maximized. Overnight lows should reach the 60`s to lower 70`s Tuesday night and Wednesday night, respectively. Daytime highs on Wednesday should reach the 80`s to lower 90`s. Additional periods of showers/thunderstorms are expected on Thursday (July 4th) through Friday as W`erly flow aloft and embedded shortwave disturbances affect our region, net surface troughing persists, and the aforementioned front wavers in a generally south-to- north manner and vice versa, in vicinity of our CWA, in response to the aforementioned shortwave trough passages. Daytime highs are expected to reach the 80`s on Thursday and Friday, respectively, and overnight lows are expected to reach the 60`s to lower 70`s around daybreak Friday morning as the front will separate a warmer/more humid air mass to the south from a slightly cooler/less humid air mass to the north. && .AVIATION /12Z Friday THROUGH Tuesday/... VFR conditions are expected for the first half to two-thirds of the TAF period. High clouds across the region will thicken today as a warm front moves across the airspace and north of the area. East to southeast flow will be favored across the area today. Some form of a lake breeze may develop but confidence in the boundary reaching KERI or KCLE is low. Increasing moisture across the region and a cold front approaching from the northwest for Saturday will allow for mid-level clouds to enter the region this evening. Convection will move in largely after midnight with coverage increasing through the night. Have VCTS to TS mentioned across the TAF sites with conditions deteriorating to MVFR. There could be windows of moderate to heavy rain with the TS toward daybreak on Saturday and TAFs may need to be refined to a more pessimistic IFR as confidence in timing increases. Outlook...Non-VFR possible in widespread showers and thunderstorms on Saturday and Saturday night. && .MARINE... Winds around 5 to 15 knots vary between SE`erly and NE`erly today as a ridge affects Lake Erie and the parent high pressure center moves from the Lake Ontario region to Atlantic waters near Nantucket. These winds are expected to trend onshore (i.e. NE`erly) late this morning through early evening courtesy of lake breeze development. NE`erly to SE`erly winds around 5 to 15 knots veer to S`erly and freshen to 10 to 20 knots tonight as the ridge exits E`ward and a warm front sweeps N`ward across Lake Erie. Waves remain mainly 3 feet or less, but occasional 4 footers develop in open U.S. waters of the central and eastern basins tonight. Given these very marginal conditions, the need for a Small Craft Advisory is not expected. S`erly to SW`erly winds around 10 to 20 knots on Saturday veer to NW`erly Saturday night as a strong cold front sweeps SE`ward across Lake Erie and is followed by a building ridge. During the day on Saturday, waves are forecast to vary from 3 feet or less in nearshore U.S. waters to 3 to 6 feet in open U.S. waters. Following the passage of the cold front, waves as large as 3 to 6 feet are expected in nearshore and open U.S. waters, especially east of The Islands. A Small Craft Advisory will likely be needed. NW`erly winds around 10 to 20 knots veer gradually to N`erly on Sunday through Sunday night as the aforementioned ridge builds from the Upper Midwest and western Great Lakes. Waves as large as 3 to 5 feet are expected, especially east of The Islands. N`erly winds around 5 to 15 knots are expected to veer gradually to SE`erly on Monday through Tuesday as the ridge continues to impact Lake Erie and the parent high pressure center moves from the western Great Lakes toward Atlantic waters near NJ. Waves are expected to subside to 3 feet or less. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...Sefcovic NEAR TERM...Garuckas/Sefcovic SHORT TERM...Jaszka LONG TERM...Jaszka AVIATION...Sefcovic MARINE...Jaszka