406 FXUS61 KCLE 070315 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1115 PM EDT Mon Apr 6 2020 .SYNOPSIS... A warm front approaches from the southwest tonight and will linger south of Lake Erie on Tuesday. Low pressure over the western Great Lakes on Tuesday will move southeast into the area on Tuesday night with an associated cold front moving through on Wednesday. Strong low pressure will develop over Northwest Ontario on Wednesday night and extend a stronger cold front across the area on Wednesday night. && .NEAR TERM /THROUGH TUESDAY NIGHT/... Minor changes were made for the late evening update. POP forecast has been lowered to account for a slow increase in coverage on the radar this evening. Previous Discussion: A warm front currently located over northern Illinois, central Indiana and across central Ohio will make its way north tonight. Moisture and temperature advection aloft will result in showers and thunderstorms developing along and ahead of this warm front. Moisture parameters are decent but aren't excessive with precipitable water values expected to be around 1 to 1.1 inches and warm cloud depths of around 7-8k feet. However, with storms moving parallel to the boundary (storm motion of WNW to ESE), training convection could pose a flooding risk as multiple rounds of showers and thunderstorms are expected to move across the area beginning later this evening and lingering into late tomorrow morning. Small hail is also possible in stronger thunderstorms. In general, QPF expected to be around 0.5 to 1.0 inches with the axis of heaviest rainfall expected to be from Toledo area to Mansfield area. Localized higher amounts of up to 1.5 to 2.0 inches possible if training of convection occurs. A lull in convection is expected tomorrow afternoon as a capping inversion will likely be in place from the overnight/morning convection. Some hi-res models such as the ARW and NMM having redevelopment of convection in the afternoon around 20 or 21 UTC. However, the 12 UTC NAM has a stout temperature inversion between 700-800 mb. If that's the case, even daytime heating will have a tough time eroding that capping inversion, keeping any convective initiation in the afternoon at bay. The more likely scenario is convective initiation to occur upstream along the cold front near lower Michigan, northern Indiana and norther Illinois area tomorrow evening. This convection is likely to grow upstream and move ESE across northern Ohio late tomorrow evening and into the overnight hours. This convection will be moving into an environment that is favorable for severe weather, with most hi- res guidance suggesting MLCAPE of 1000-1500 J/kg, 0-6km bulk wind shear of 40-60 knots, and steep mid-level lapse rates of -7 to -8 C/km. Large hail and damaging winds are the most likely hazards but an isolated tornado and localized flooding are both possible as well. For this reason, the Storm Prediction Center has included much of our forecast area in a slight risk for severe weather. It's important to note that there is still a lot of uncertainty regarding the potential severe weather for tomorrow afternoon through tomorrow night because of that capping inversion mentioned earlier. Because of that, areal coverage of thunderstorms (and thus severe weather) may be quite a bit lower than expected. Additionally, the timing of expected severe weather is not diurnally favorable for our area as instability won't be maximized after dark. It will be important to monitor future updates, especially after tonight's convection. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Broad upper level ridging will take place across the area Wednesday and Wednesday night. The ridge will amplify with time as an upper level low pressure system dives southeast toward the area by Thursday morning. The upper level ridge will cause surface high pressure to move east across the area Wednesday. A strong cold front will move east across the local area Wednesday night with strong cold air advection to follow into Thursday. Deepening low pressure at the surface will move into the central and eastern Great Lakes through the period to force the cold front east. Showers in the wake of the system expected to affect the local area tomorrow will gradually pull out to the east Wednesday. Fair weather following this system will be very short lived as more showers push east into the area ahead of cold front. Can't rule out a rumble of thunder with the showers Wednesday night. Warm air advection will take place on the west side of the surface high pressure albeit brief ahead of the cold front Wednesday night. && .LONG TERM /FRIDAY THROUGH MONDAY/... Upper level troughiness will dominate the eastern third of the country Friday into Saturday and then shift east off the coast Saturday. Broad troughiness will linger over the lower 48 states through Monday even though a fast moving upper level ridge will move over the area by Saturday afternoon. Surface high pressure will move east across the Gulf Coast states and extend a ridge north across the local area by Saturday. The ridge will move east Saturday night A cold front will move east across the forecast area Sunday night and become nearly stationary. Meanwhile, a wave of low pressure in response to an upper level shortwave will move northeast along the boundary Sunday night. This will force the front southeast of the area Monday as high pressure ridge begins to build into the area. Showers will retreat to the east Friday with very limited chances across the south. Otherwise, looking at minimal chances for showers through the rest of the forecast period. A gradual warming trend will take place early in the period and then cold air advection takes place behind the cold front by the end of the weekend into early next week. && .AVIATION /00Z Tuesday THROUGH Saturday/... Fair weather with VFR conditions prevail across the region early this evening but conditions are expected to deteriorate overnight as a developing warm front becomes more active from north central Ohio west to near CHI. Already some weak radar echoes are spreading ESE across northern Ohio with more activity west of CHI. So we can expect thickening and lower clouds overnight as showers become more numerous from MFD and points west. IFR Cigs and visibility are expected once the showers become more numerous and moisten the boundary layer toward morning at TOL and FDY and toward noon at CAK and MFD. Isolated to scattered thunderstorms are expected to develop as well mainly after midnight and become more numerous in the afternoon on Tuesday. Light winds are expected except some higher gusts are possible in storms Tuesday afternoon. .OUTLOOK...Non-VFR possible with showers and thunderstorms Tuesday night through Wednesday morning. Non-VFR again possible Thursday into Friday with rain and low ceilings. && .MARINE... Generally light and variable winds expected through Wednesday and then increasing westerly flow will develop Wednesday night in the wake of the exiting storm system Thursday. A persistent west- northwest flow will continue through Friday and then diminish by Saturday as the flow becomes more southwest. Will likely need small craft advisory late Wednesday night into Friday evening. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...LaPlante/Saunders NEAR TERM...LaPlante SHORT TERM...Lombardy LONG TERM...Lombardy AVIATION...LaPlante MARINE...Lombardy