Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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096 FXUS61 KCLE 191505 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1005 AM EST Sun Jan 19 2025 .SYNOPSIS... A low pressure system will move northeast along a cold front up the East Coast today. This low will help pull an Arctic cold front across the area by tonight. Arctic high pressure will slowly build into the region by Tuesday. && .NEAR TERM /THROUGH MONDAY/... 10:00 AM Update: A broad area of light lake effect snow is ongoing across the Cleveland metro and surrounding areas. Radar returns are gradually beginning to increase with this activity, with webcams and ASOS sites suggesting some visibility drops to 2-3 miles at times along with some very light accumulations of no more than 0.5", primarily on untreated surfaces to this point. The immediate forecast is on track and only made a couple of minor tweaks to match to current obs/radar. Looking ahead, am not planning on making any changes to the cold headlines on this shift as the advisory issued early this morning should hold for both tonight and Monday night. As alluded to below, Tuesday night into Wednesday morning will be the coldest and most impactful night (with the duration adding to infrastructure impacts by then). Regarding the snow, the relatively most organized band at this point stretches across parts of Cuyahoga and into Medina County. Flow will start slowly backing soon, so should see activity focus from Cuyahoga into Summit by midday and then gradually pivot east across Northeast OH through the afternoon. As synoptic moisture increases and the airmass cools this lake effect will gradually intensity. Will need to closely evaluate secondary snowbelt counties, as there are increasing indications that a burst of snow with origins to Lake Michigan and decent synoptic support from a shortwave will move near the western lakeshore and into the Cleveland metro, northern secondary snowbelt counties, and then the primary northeast OH snowbelt this evening. Event total accumulations could squeak over 4" over a 12-18 hour period in some secondary snowbelt counties, and could squeak over 6" in an 18-24 hour period in places such as Geauga County. No headline changes with this package, though did make modest changes to QPF and snow ratios this evening to bump snow up a bit in the Cleveland metro, along with places such as Lorain County, northern Medina/Summit/Portage Counties, and Trumbull County. Satellite also depicts broad synoptic lift over much of the region, with radar suggesting light snow is falling aloft but not reaching the ground. Should see some light synoptic snow reach the ground across the area this afternoon with modest accumulations and impact. Greater concern will be the potential for a fairly widespread batch of snow showers, with potential for a few heavier snow showers or squalls, along the leading edge of the incoming arctic air moving into much of northern Ohio from the west later this afternoon and this evening. With increasingly cold temperatures, these snow showers can easily stick to roads, which along with visibility drops may lead to travel impacts. Am planning on doing some messaging for that potential this shift. Previous Discussion: The plunge into a mid-January deep freeze starts today. The opening act will be a multifaceted snow event across the area with a mix of traditional lake effect snow with additional snow thanks to some synoptic features. Some light returns are already starting to appear on the radar this morning as 850 mb temperatures continue to crash across Lake Erie with a light northerly flow. Right now, the bulk of the instability and moisture is very shallow across the region within the first 4-5 kft of the atmosphere. However, as additional low level moisture and instability off Lake Huron enter and some mid-level lift and moisture from the southeast United States low also arrive, the setup for lake effect snow will become better throughout the day. This event will be intriguing from the start with the mean flow being close to due north. This will allow for the best snow to be around the Cleveland metro to start, especially the eastern suburbs and will go with about an inch by Noon and another 1-3" just after sunset. As the day progresses, some of the synoptic features will also take aim into the region. The southeast low will be halfway up the East Coast and the back edge of the precipitation shield may skirt some of the southeast portions of the forecast area. This system will also pull an Arctic cold front across the area and there should be some snow that develops upstream in Indiana and Michigan (with some Lake Michigan enhancement) that will push across the entire forecast area and could be the culprit for an inch or so of snow in the Mansfield/Mid-Ohio region. As this Arctic front crosses the area this evening and tonight, winds will back to the northwest and then west, allowing for the lake effect snow to start to pivot into far NE OH and eventually NW PA. The most potent lake effect snow will remain tied to wherever the Lake Huron connection sets up and that should cascade from the eastern Cleveland suburbs up I-90 and into Erie County, PA. However, the pivot will be quick through the night and suspect that this connection will be into western New York quickly on Monday morning. With that, have cropped back snow totals just a touch and have upgraded Erie County PA from the Winter Storm Watch to a Winter Weather Advisory. Some scattered snow showers could continue to impact Erie County PA through Monday, but the main focus will likely be offshore. Elsewhere, high pressure will start building into the region and conditions will be on a dry and clearing trend tonight into Monday. Outside of the snow, the widely announced cold outbreak will start tonight behind the Arctic cold front. Temperatures will struggle today and many locations may have even already seen their daily high in the 20s. Temperatures will fall into the single digits or even near zero tonight, as 850 mb temperatures continue their crash beyond the -20C value. Strong west winds will allow for wind chill values in the double digits below zero. High temperatures on Monday will struggle to do much with most areas remaining in the single digits and wind chills will remain frigid well below zero. Since wind chill values will stay above -25F for tonight into Monday, have upgraded the Extreme Cold Watch to a Cold Weather Advisory for the onset of this event and through the previous watch period through Wednesday morning. More details on the cold for Monday night through Wednesday night is in the short term section below. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... The coldest weather in several years is still on track to impact the region through mid week, and that remains the main story since the actual temperatures, wind chills, and duration will create infrastructure and public safety concerns. Expansive mid/upper longwave troughing covering much of the CONUS to start the week will gradually lose amplification through Wednesday night as the associated mid-level closed low (Polar Vortex) near Hudson Bay slowly lifts farther northeastward. As this happens, a broad surface high over the Tennessee and Lower Ohio Valleys Monday night will build north into the southern Great Lakes/northern Ohio Valley Tuesday night and Wednesday before shifting across the Mid Atlantic region Wednesday night. This all leads to the cold weather peaking Monday night through Tuesday night before starting to moderate. The 00Z NBM guidance has trended back slightly colder for the Monday night and Tuesday timeframe after a few runs of "warming." This makes sense given a southwesterly boundary layer flow causing the arctic air to wrap in from the southwest, which is typical during the strongest arctic outbreaks in our region. Did a blend of the NBM with 5-10% of the RGEM for temperatures Monday night through Tuesday, which gives lows of 0 to -5 F Monday night and highs of about 3 to 8 F Tuesday. These temperatures combined with west- southwest winds of 5-15 knots will lead to wind chills of -15 to -20 F Monday night and -10 to -15 F Tuesday. As the surface high builds north Tuesday night and Wednesday, the clearing skies and lighter winds still looks to support the coldest night. Continued with actual lows of -8 to -15 F Tuesday night followed by a rebound into the 8 to 15 F range for highs Wednesday. This will lead to wind chills approaching -25 F early Wednesday morning, which is Extreme Cold Warning criteria. As described in the Near Term section, the decision was made to issue a Cold Weather Advisory for the entire Sunday night through Wednesday morning period for the wind chills staying closer to -15 F most of the time, but the cumulative effects of several days of this combined with colder wind chills Tuesday night/early Wednesday morning may necessitate a later upgrade to a warning for Tuesday night/Wednesday morning. This will be monitored over the next 48 hours. Subzero lows will continue Wednesday night in far eastern Ohio and NW PA, but the airmass will be slowly retreating at that time. See the Cold Weather Advisory for information on impacts to infrastructure and public safety. Other than the cold, lake-effect snows will continue Monday night through Tuesday night before the high gradually shuts down the activity Wednesday and Wednesday night, but the west-southwesterly boundary layer flow will keep the main band offshore over western NY. Only a half inch or so of snow is expected near the lakeshore of Lake, northern Ashtabula, and Erie Counties in any 12 hour period as occasional snow showers brush the region combined with weak shortwave perturbations and daytime instability supporting occasional light snow over land. Any snow will be very dry and "dusty" given the deep arctic air mass and a DGZ near the ground, below the best moisture and lift. && .LONG TERM /THURSDAY THROUGH SATURDAY/... As mentioned above, the worst of the arctic air will retreat by Thursday, but northwesterly mid/upper flow will continue downstream of very persistent mid/upper ridging near the West Coast. This will keep the Great Lakes and Northeast U.S. in a cold and active winter pattern. Another shortwave will drop from the northern Plains through the Mississippi Valley Thursday. Timing of this feature and its associated cold front remain uncertain, so held off on any light snow until Thursday night and Friday as the trough axis passes overhead. Behind this shortwave, there could finally be a stronger warming trend as heights briefly rise ahead of the next trough and blast of cold air, so have slowly warming temperatures through next weekend. Highs will moderate into the low/mid 20s Thursday and Friday, with upper 20s/low 30s Saturday. && .AVIATION /12Z Sunday THROUGH Thursday/... Conditions across the region continue to be a mix of VFR and MVFR. Conditions will be remain similar over the next several hours until snow starts to blossom across the region. While there will be several mechanisms helping with snow potential at all terminals, the lake effect snow will be the most impactful with the potential for IFR. The IFR with the lake effect should stay east of KCLE, but all of KCAK, KYNG, and KERI are all in play with any IFR starting toward KCAK and pivoting east to KYNG and then KERI this afternoon and evening. Elsewhere, snow should be limited to just MVFR impacts and the snow potential at KTOL and KFDY remains very conditional and will maintain a PROB30 window for MVFR snow. An Arctic front will cross the area and winds will shift from the north to northwest and then west through the period. Winds behind the front will have gusts in the 20-25 kt range. Outlook...Non-VFR ceilings and visibility in snow will linger across far NE OH and NW PA into Monday with some potential for non-VFR to redevelop for Monday night into Tuesday. && .MARINE... N winds of 5-10 knots on the lake today will become W and increase to 15-25 knots tonight behind an arctic cold front. Winds will then back to WSW and increase to 20-30 knots Monday into Monday night before decreasing to 15-25 knots Tuesday. These winds combined with deep arctic air and water temperatures of 32 to 33 F will lead to heavy freezing spray where water remains open in the open waters from Avon Point to Ripley. However, expect ice to rapidly increase through midweek, and by the time the SW winds diminish to 10-15 knots Tuesday night through Thursday, these open waters may be mostly ice covered. The Heavy Freezing Spray Watch was upgraded to a warning from 06Z Monday through 06Z Wednesday to account for the coldest temperatures and strongest winds where water remains open in the open waters from Avon Point to Ripley. Small Craft Advisory issuance has been suspended until further notice for nearshore waters from Maumee Bay to Ripley due to extensive ice cover. && .CLIMATE... Arctic air will arrive early Monday morning 1/20, and persist through Wednesday 1/22. The coldest period is expected to be late Tuesday night into early Wednesday morning with current forecast temperatures approaching record lows for 1/22. Below are the current record low temperatures for 1/20-22. Date Toledo Mansfield Cleveland Akron Youngstown Erie 01-20 -17(1985) -22(1985) -18(1985) -24(1985) -20(1985) -15(1985) 01-21 -20(1984) -19(1985) -17(1985) -24(1985) -20(1985) -16(1985) 01-22 -12(1936) -10(1936) -10(1936) -13(1936) -9(2022) -7(1970) && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Cold Weather Advisory from 1 AM Monday to 10 AM EST Wednesday for OHZ003-006>014-017>023-027>033-036>038-047-089. Winter Weather Advisory until 10 AM EST Monday for OHZ011>014- 089. PA...Cold Weather Advisory from 1 AM Monday to 10 AM EST Wednesday for PAZ001>003. Winter Weather Advisory from 4 PM this afternoon to 4 PM EST Monday for PAZ001-002. Winter Weather Advisory from 4 PM this afternoon to 10 AM EST Monday for PAZ003. MARINE...Heavy Freezing Spray Warning from 1 AM Monday to 1 AM EST Wednesday for LEZ166>169. && $$ SYNOPSIS...Sefcovic NEAR TERM...Sefcovic/Sullivan SHORT TERM...Garuckas LONG TERM...Garuckas AVIATION...Sefcovic MARINE...Garuckas CLIMATE...