FXUS61 KCLE 210530 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 130 AM EDT Tue Apr 21 2026 .WHAT HAS CHANGED... A Freeze Warning remains in effect for most of our CWA from 8 PM this evening to 10 AM Tuesday morning, except for Lucas, Ottawa, Sandusky, Wood, and Hancock Counties. && .KEY MESSAGES... 1) One more unseasonably cold night tonight with below freezing temperatures, especially in NE Ohio and NW PA. 2) Much warmer air will arrive Tuesday and persist through early next week, but the pattern will turn active with numerous chances for rain starting this weekend. && .DISCUSSION... KEY MESSAGE 1... Water vapor loops show an amplified mid/upper pattern that remains in place this afternoon characterized by a deep trough over the eastern CONUS, closed low offshore of the west coast, and broad ridge in between across the Intermountain West and Plains. The eastern trough continues to keep our region in a NW flow pattern, with temperatures running a solid 25 degrees below normal this afternoon. Despite the cold, a large area of surface high pressure sliding into the southern Great Lakes this afternoon has allowed most of the lake-effect clouds to dissipate, and this is supporting plenty of sunshine with afternoon cumulus. The cold airmass in place and influence of the surface high will set up another cold night tonight. Much of NE Ohio and NW PA should end up colder than last night given the mostly clear skies and light winds, so expect widespread lows in the 25-30 F range in NE Ohio and NW PA, with some low 20s in interior NW PA. However, as the high drifts into the Appalachians tonight, low- level southerly return flow will quickly begin in NW Ohio. These S winds should increase to 5-15 knots by 09Z, and this combined with increasing high level cirrus ahead of a warm front should allow NW Ohio to be quite a bit milder. Lows will likely stay in the low/mid 30s in much of NW Ohio. Kept Lucas, Ottawa, Sandusky, Wood, and Hancock Counties out of the Freeze Warning, and it is possible that the rest of NW Ohio and parts of north central Ohio do not reach freezing either, but it will be close either way. Even if some of the NW and north central counties in the Freeze Warning do not reach freezing, they will still have patchy frost. Temperatures will quickly warm after sunrise Tuesday morning in the developing warm air advection pattern. KEY MESSAGE 2... Much warmer, more pleasant temperatures remain on track to begin Tuesday as the surface high continues to drift into the Mid Atlantic states allowing for southerly return flow and resultant warm air advection. A warm front will lift across the region in the late morning and early afternoon. The main impact should only be some high and mid-level clouds given a significant amount of low-level dry air, but the latest HREF hints at some light showers or sprinkles possible in NW PA where isentropic ascent is maximized in the early afternoon. NBM slight chance POPS look reasonable for this. Otherwise, the better chance for rain will hold off until Tuesday night and early Wednesday morning as a cold front sags across the region in response to a mid/upper shortwave dropping through the continued longwave trough over the Northeast CONUS. Low-level moisture return will be very limited ahead of the front, so this will keep instability weak, but synoptic support from a modest 60-75 knot upper jet streak nosing into the central Great Lakes will generate an area of showers and a few rumbles of thunder that will slowly sink southeastward across the region Tuesday night into Wednesday morning. Most rainfall should only be 0.25 inch or less, with the greatest amounts likely in NW Ohio. Canadian high pressure at the surface building into the central Great Lakes behind the front will gradually dry out all areas Wednesday as the boundary slowly pushes south and washes out, with dry and mild conditions through Thursday. Daily lake breeze development will keep lakeshore areas cooler Wednesday and Thursday. A more active but also lower confidence pattern will start to develop Friday and persist through early next week. The closed mid/upper low off the west coast will gradually move into the northern Plains by Friday and evolve into a broader and larger closed low while the old eastern CONUS mid/upper trough closes off into a closed low offshore of New England. This will pinch mid/upper ridging in between across the Ohio Valley Thursday and Friday. The ridge will gradually shift as the northern Plains closed low tries to come farther east, and that will slowly draw moisture into our region late Friday and Friday night ahead of a cold front. However, like all blocking patterns, timing of this front is uncertain, and it will likely remain near or just west of our region through next weekend keeping unsettled conditions in place. Deeper moisture may arrive by Monday as the block attempts to weaken and draw in a stronger SW flow from the Mississippi Valley, but evolution is very uncertain Friday through Monday. Chances for rain and occasional thunder are very broad Friday night through Monday, and timing will be fine tuned as we get closer since it certainly will not rain all the time. && .AVIATION /06Z Tuesday THROUGH Saturday/... The area will start with VFR and mostly clear conditions and light southerly flow with high pressure departing east this morning. Some mid- and high-level clouds will enter through the early morning hours and spread across the terminals. For Tuesday, a warm front will cross the area and allow for enhanced south to southwest flow across the region. Gusts of 20 to 30 kts are expected with good mixing in the warm sector. The front will come back south as a cold front tonight and bring some scattered showers to the region. Showers could have some embedded thunder within them, but too low of confidence to include in a TAF at this time. In addition, the intensity of any rainfall with the showers appears low and the potential for non-VFR with the rain is decreasing. Ceilings will lower with and behind the boundary and some MVFR is possible just after the TAF period. Outlook...Non-VFR possible in scattered showers and storms Friday and Saturday. && .MARINE... The lake is starting out quiet early this morning with light southerly flow over the basin. A warm front moving through the region will allow for increasing south to southwest flow this afternoon. The winds should hit a wall with the cold dome over the lake and suspect that winds will generally stay in the 10 to 15 kt range except for right at the lakeshore. The warm frontal boundary will sag south as a cold front tonight into Wednesday and bring some light onshore flow. High pressure will then enter over the lake and bring light and variable flow. This system will move east for Thursday and allow for light southerly flow to be favored. A low pressure system will target the region for Friday and Saturday. Southeast to east flow will increase ahead of this system on Friday. There is some uncertainty on the trajectory for this system over the weekend but once the system passes, winds will shift to the north for Saturday and Sunday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Freeze Warning until 10 AM EDT this morning for OHZ009>014- 018>023-027>033-036>038-047-089. PA...Freeze Warning until 10 AM EDT this morning for PAZ001>003. MARINE...None. && $$ DISCUSSION...Garuckas AVIATION...Sefcovic MARINE...Sefcovic