253 FXUS61 KCLE 011145 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 645 AM EST Wed Mar 1 2023 .SYNOPSIS... A warm front will approach the area today ahead of a low pressure system that will move through the middle of the Great Lakes region. This low will extend a cold front across the area tonight. High pressure will build into the region behind the front for Thursday as the front stalls near the Ohio River. A low pressure system will develop over the southern United States on Thursday night and move northeast into the area on Friday. && .NEAR TERM /THROUGH THURSDAY/... Radar flared up a bit more than expected this morning as some light showers move through the region. The radar returns are more bark than bite as the rain is really *just* enough to wet the pavement and allow for a flick or two of the wipers. Have extended chance PoPs through NE OH/NW PA over the next couple of hours to reflect these rain showers. Previous Discussion... A warm front will enter the area today and allow for a quiet, dry, and well above normal Wednesday to kick off the month of March. Some rain showers are encroaching into NW Ohio ahead of the front and these will cascade across the lake into NE OH/NW PA later this morning with a bit of isentropic lift across the area. There could be a very brief window of wet snow with this feature in NW PA, but warm air advection will be aggressive across the region and anything should melt quickly or lift out of the area before becoming a problem. A drier air mass behind the front and 850 mb temperatures approaching 10 C will enter the region by this afternoon and expect temperatures well above the normal of lower 40s. Record high temperatures are in the mid to upper 60s for today and there should be enough mixing of the warmer temperatures down to the surface to make a solid run at them, but think most of the area will just fall short, as the front will get hung up just a bit on the lake. The best spot of a record may be Akron-Canton, where the record is a bit cooler than surrounding sites at 66 degrees. Some better moisture will advect into the region later this afternoon into the evening hours right ahead of a cold front. There will be quite a bit of dry air for this moisture to work through to allow for this front to trigger rain showers as it moves through. By the time the front approaches the southeast counties this evening, there is a shot for some rain and have a chance PoP, but the best setup is south and east of the forecast area. Don't think that temperatures will quite plummet behind the front tonight with clouds in the area and the slow pace of the cold air advancing into the region so a mix of mostly 30s and perhaps some 40s south should be the minimum overnight. High pressure will build into the region for Thursday and keep the area dry. An inversion will be in place across the region and should hold some low clouds through the day on Thursday. There is potential for some of the clouds to erode in the southern counties and temperatures there may make a run at 50 degrees. Otherwise, expect a small diurnal bump in temperatures with just 40s throughout. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... An active short term forecast period is expected, as a moisture-laden and fairly deep low pressure tracks from the southern Plains Thursday evening into the middle Mississippi Valley by Friday morning. This system will progress further into the southern Great Lakes (somewhere between southern lower Michigan and northern Ohio, perhaps over Lake Erie) Friday night with the low then drifting east towards Lake Erie. The system will then weaken on Saturday as a coastal low becomes favored off the East Coast. This system will bring moderate to heavy precipitation, largely in the form of rain, to the entire area Friday into Friday night. Some showery precipitation will linger Saturday, especially in Northeast Ohio and Northwest Pennsylvania. Some wintry precipitation is still possible, especially across northwestern Ohio and northwestern PA, though we're still looking at a large majority of the QPF with this system falling as rain across our forecast area. Gusty winds can be expected Friday and Friday night, perhaps lingering into Saturday. The main concerns with this system, in order from largest to smallest, appear to be rainfall potentially leading to flooding, gusty winds, and wintry weather potential. These will be broken down below... Trends in Guidance & Forecast Confidence/Uncertainty: No wholesale changes in recent guidance, but some subtle trends. The most notable trend has been for the system to arrive a bit slower, leading to an increasing likelihood that most of our area remains dry Thursday night. Locations from Northeast Ohio into Northwest PA may have to wait several hours into the day Friday to see precipitation. Feel this slower trend is reasonable and made some adjustments to the onset of PoPs late Thursday night into Friday. Another subtle trend has been for guidance to trend towards lower heights extending from Hudson Bay southeast across northern New England and into the Canadian Maritimes ahead of the approaching low pressure. This is likely a result of the pattern over eastern North America feeling the influence of a retrograding block into Greenland later this week. These lower heights lead to upper-level confluence increasing ahead of the system. This increased confluence may be partially responsible for the slower trend with the onset of precip and could allow for chilly/dry air to be slightly more stubborn ahead of the storm. This has led to a slight bump back south and chillier trend among some 0z guidance. Another source of uncertainty is when the system will reach peak intensity and begin occluding/weakening. This will help dictate QPF across our area. The Canadian is on the late side and brings heavier QPF with 1.50-2.50" across most of our area. The NAM and Euro are on the other extreme, showing the low occluding and beginning to fill quicker, keeping the heaviest QPF just to our south/west with more modest QPF of 0.50-1.50" across our area. Hard to say which way that will go but increased confluence ahead of the low could point towards it beginning to fill earlier and slightly lower QPF in our area. Heavy Rainfall & Flooding Potential: A period of moderate to heavy rain still appears likely on Friday as a sloped warm frontal surface lifts across our area ahead of the approaching low pressure. Strong isentropic lift and frontogenesis beneath favorable upper-level divergence are still expected to squeeze out unseasonably high PWAT values of a bit over one inch with a bit of elevated instability trying to advect as well. Precip rates will generally maximize during the day Friday with the lift described above...however, as the deep low aloft and occluded front sweep through from west to east Friday evening some rain will continue. Depending on the exact low track, the system's deformation zone could get into northwestern Ohio points east across Lake Erie into northwest PA Friday evening/night, which could prolong steadier precipitation in this area. Overall, the total QPF forecast is similar to the prior but slightly lower, generally in the 1.00-1.50" range but trending upwards of 1.75" to the southwest towards Mount Vernon. On the balance, this amount of rainfall would probably lead to some minor flooding of some streams, creeks, and poor- drainage areas due to a period of sufficient rates to cause quick run-off across our saturated late-winter soils. As this run-off makes it into the rivers, they will sharply rise, and suspect we'll see a number of points reach minor to perhaps moderate flood when examining ensemble river forecast guidance and factoring in recent QPF trends. The greatest overall flooding potential appears to be from Northwest Ohio and into North Central Ohio (from near Toledo to Canton points southwest), lining up well with the Day 3 Slight Risk for excessive rainfall area from the WPC...though, some prone areas could see flooding farther northeast. If QPF trends back up and 2.00"+ amounts look to work into our area, then more widespread flooding with more river gauges rising to moderate to perhaps major flood would be possible - though the risk of that appears to have trended down somewhat. Gusty Winds: East-southeast winds will ramp up Friday afternoon and early evening as a 60-70 knot low-level jet works through from west to east. However, a stout low-level inversion and general warm air advection regime argue against efficient mixing in this window. That said, expect 30-40 MPH gusts area-wide in this window with 40-50 MPH gusts possible in parts of the area, especially west of I-71 (due to modest downsloping and general flat/open terrain) and along the eastern lakeshore (due to downsloping). It is possible that a Wind Advisory will be needed for part of the area in this window. Gusts briefly lull Friday evening as the low moves nearby or overhead with gusty west-northwest winds returning on the backside late Friday night into early Saturday. The low will be filling/weakening by the time these backside winds occur, so current impression is that 30-40 MPH gusts will largely cover the backside winds later Friday night/early Saturday. Wintry Weather Potential: Still minimal for most of our forecast area, but Northwest Ohio (including Toledo) and Northwest Pennsylvania (including Erie) still appear to have some potential for more impactful wintry precipitation. As precipitation first spreads in from the south Friday morning wet bulb cooling could allow the leading edge of precip to fall as some sort of rain/sleet/wet snow mix. For most of our area, this would be very brief and of little impact, and the slightly slower onset of precip should generally allow surface temperatures to warm more before precip moves in. Regarding our northwest fringes (i.e. Toledo), the slight south shift in the low track noted on some guidance (such as the 0z GFS and CMC models) could keep the 850mb low track just south of Toledo. If this occurred, dynamic cooling in the system's deformation zone may allow moderate to heavy, wet snow to continue longer there. There is low confidence in this occurring, as the NAM and Euro take the 850mb low north of Toledo and still have mainly or all rain. Probabilities on the 0z GFS and Euro ensembles for greater than 3"+ or 6"+ of snow are still higher into Michigan, but have increased a bit in the Toledo area. On the flip side into Northwest PA, it seems like there should still be sufficient warm air advection aloft to change things over to "not snow" at some point...however, trends noted above for a somewhat better injection of chilly/dry air into the northeast ahead of this system may open the door for some mixed precipitation in Northwest PA, especially in the higher terrain away from Lake Erie. Introduced a bit of sleet and freezing rain for a time Friday afternoon in eastern Erie and Crawford Counties, but was conservative with this mention for now. Brisk easterly winds will be in place, and this could continue to advect in lower dew points and try to prolong any mixed precipitation. As for the rest of our area, some ensemble members ticked south enough to bring some accumulating wet snow or perhaps some mixed precipitation into more of northern Ohio (including Cleveland and Youngstown), but these solutions are in the minority. Overall, would like to give another cycle or two to see if the slight colder trend noted on the 0z models and ensembles is legitimate or not before introducing too much snow or mixed precip into the forecast across some of our northern counties. && .LONG TERM /SUNDAY THROUGH TUESDAY/... Surface high pressure builds in Sunday and Sunday night. A weak shortwave does cross through the Great Lakes Sunday morning, though for now kept a dry forecast. Weak low pressure is expected to develop to our west Monday into Monday night and move through on Tuesday. This will lift a warm front through Monday, followed by a cold front on Tuesday. Forcing and moisture appear modest so just have low POPs for light precip (mainly rain) at the moment. Temperatures will be near average for Sunday but warm a bit for Monday and Tuesday, followed by a cooler trend towards midweek. && .AVIATION /12Z Wednesday THROUGH Sunday/... Rain ahead of a warm front is moving through NE OH/NW PA this morning. The rain is having minimal airport impacts as ceilings are only falling to a mid level deck between 5 and 10 kft and vsby remains in the VFR range. The warm front will continue north and rain and this mid-level ceiling deck will clear the region. Generally southerly winds will increase across the region behind the front, while scattered VFR clouds should be in place. A cold front will cross the area tonight and generate some showers in southeast areas before exiting. Felt a tiny bit more comfortable in some coverage around KCAK and KYNG to have a vicinity shower mention, but still low confidence in something hitting a terminal. Winds will shift to the west/northwest with the cold frontal passage. VFR will still be favored but a low ceiling could try and develop to the lee of the lake, especially locations like KCLE and KERI. Outlook...A system will impact the area Thursday night into Saturday with non-VFR possible in rain and/or snow. && .MARINE... Main marine focus over the coming days will be a strong low pressure approaching from the southwest on Friday, moving near or over Lake Erie Friday night, and gradually moving east and weakening into the weekend. Strong east-northeast winds are expected to develop ahead of the low on Friday with 20-30 knots quite likely and low-end gales not ruled out, especially over the open waters. Winds briefly lull Friday evening as low pressure makes its closest approach, with gusty west-northwest winds (likely 15-25 knots) developing late Friday night into Saturday behind the low. Winds gradually diminish Saturday and should be light by Saturday night and Sunday. At the moment, high-end Small Craft Advisories appear quite likely for Friday through Saturday with non-zero potential that we need some Gale Warnings. Confidence not high enough for a Gale Watch this morning, though the lake will be rough either way. && .CLIMATE... High temperatures on Wednesday may be near record values. The following are the record high temperatures at our climate sites for Wednesday, March 1. Date Toledo Mansfield Cleveland Akron Youngstown Erie 03-01 65(1997) 68(1972) 69(1972) 66(1972) 68(1939) 66(1997) && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Sefcovic NEAR TERM...Sefcovic SHORT TERM...Sullivan LONG TERM...Sullivan AVIATION...Sefcovic MARINE...Sullivan CLIMATE...