059 FXUS61 KCLE 160608 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 208 AM EDT Sun Oct 16 2022 .SYNOPSIS... High pressure ridges into the region through the morning. A cold front moves across the area this afternoon. Low pressure will then develop over the northern Great Lakes and meander across the region through the middle of the week. && .NEAR TERM /THROUGH TONIGHT/... 5H jet moving through the upper level trough is assisting with the development of cloud cover across the region. Cant completely rule out a passing sprinkle across the region. The best chances of this occurring from Canton/Akron to Youngstown. These clouds are messing with temperatures and keeping them warmer than anticipated across the east with the frost advisory. Will leave it up for now but may cancel early if temperatures continue to warm up. In any event there still should be patchy frost across the OH portion of the advisory. A decent frost should still occur across NW PA. Skies then clear in the wake of this jet energy as another cold front moves across the area through the afternoon. Highs today should warm into the 60's for most locations. The next ripple of jet energy arrives tonight with some showers developing across NE OH into NW PA. The greatest coverage should be out over the lake. IT will still be cool across the region tonight but with increased cloud cover and winds remaining above 8 mph we shouldn't have to deal with any widespread frost. Lows tonight on the mid/upper 30's. Warmer along the lakeshore with 40's common from Cleveland to Ripley. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... A very cold, wet pattern with the potential for even wet snow will be the story of the early to mid week period, more typical of mid November. Starting off Monday, a highly amplified mid/upper pattern will be well established characterized by sharp western CONUS ridging and a deep, closed low centered over the central Great Lakes, putting the entire central and eastern CONUS under the influence of a deep longwave trough. This will allow modified arctic air to pour southward through the Upper Midwest, Great Lakes, and Ohio Valley through mid week as shortwave troughs rippling through the broad cyclonic flow reinforce the strong cold air advection. During the day Monday, the boundary layer flow will average 250 degrees. H85 temps around -3 C in the morning will fall to around -5 C by evening, and with lake temps around 15 C, this will set up extreme instability with lake induced CAPE values exceeding 1000 J/Kg as equilibrium levels rise over 10,000 feet through the day. Moisture depth will be increasing as a surface trough/reinforcing mid-level shortwave approaches, and with the aforementioned very favorable parameters, a strong lake response will develop. The boundary layer flow will keep the band offshore during the day, but went with chance PoPs over much of northern Ohio and NW PA since the cold pool aloft will support diurnally driven showers inland. Things get interesting Monday night and Tuesday morning as the aforementioned surface trough and parent mid-level shortwave drop through the region bringing a chunk of colder air and attempting to veer the boundary layer flow. H85 temps dropping below -5 to -6 C will raise lake induced CAPE to 1300-1500 J/kg (very extreme) with equilibrium levels rising above 12,000 feet (also very impressive). This combined with deep moisture, strong Omega, and decreasing shear through the boundary layer will support a strong west-east band of heavy lake-effect precip over the lake attempting to push south/southwest into the primary snowbelt of NE OH and NW PA. There will be a typical early season lake aggregate thermal trough in place, which often causes the wind to struggle to veer, and this case is no exception. The NAM keeps a 260-270 flow Monday night into Tuesday morning, while the CMC veers the flow to 290-310 behind the boundary. Convergence ahead of the boundary combined with south shore convergence in the vicinity of the band will further support a strong band, but how far south and southwest will it push? At this time, have likely/categorical PoPs gradually expanding into the snowbelt Monday night and Tuesday morning. In terms of snow potential, odds of some accumulation are increasing wherever the band can set up (except for communities along the lakeshore due to the warmer lake influence). BUFKIT profiles from the NAM suggest strong Omega and solid moisture through the DGZ (-12 to -18 C layer) early Monday night, gradually decreasing through Tuesday morning. This combined with wet bulbing within heavy precip will lead to a changeover to snow in the higher elevations. Thunder is likely given the extreme instability too. At least 1 to 2 inches of slushy snow is not out of the question in places like Edinboro, Jefferson, and Chardon (inland higher terrain areas) depending on how far the band can push and where it persists. It is still early, and a lot can change, but we are trending toward at least light accumulations. Tuesday afternoon through Tuesday night, strong cold air advection will continue with good synoptic moisture wrapping westward through the Great Lakes from the Atlantic as the deep mid/upper low persists. This combined with continued W to NW flow will keep lake- effect and lake-enhanced precip going. Any snow will change back to rain during the day Tuesday, and guidance hints at the flow backing ahead of another shortwave which could shift the heaviest/most persistent back offshore, but kept high PoPs in many areas from north central OH through NW PA through the day. Rain/snow showers will continue Tuesday night as flow attempts to veer again behind the trough, but temps should be slightly warmer than Monday night limiting any accumulations. Highs Monday and Tuesday will be generally stuck in the mid 40s with lows in the low/mid 30s Monday night and low/upper 30s Tuesday night. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... The deep, closed low over the Great Lakes will gradually lift into Hudson Bay Wednesday and Thursday leaving the deep longwave trough axis across the eastern CONUS. This deep trough will gradually shift east Friday and Saturday as broad ridging expands from the Plains. Continued cold air advection and reinforcing shortwaves will keep periods of lake-effect showers going in NE OH and NW PA Wednesday, but this activity will gradually diminish and shift into NW PA/western NY Wednesday night and Thursday as the boundary layer flow backs. Dry conditions are expected by Friday and Saturday as the ridging builds into the region. Highs Wednesday will continue to be stuck in the low/upper 40s before rebounding into the upper 40s/low 50s Thursday and mid 50s to near 60 Friday. Highs will reach the low 60s by Saturday. && .AVIATION /06Z Sunday THROUGH Thursday/... VFR conditions are expected through tonight with a few sprinkles possible from KCAK to KYNG through sunrise. Minimal impacts so did not mention in the TAF's. Otherwise we should see a light southerly winds become westerly through the afternoon as a cold front sweeps across the region. Winds increase slightly with the frontal passage but should not exceed 10 knots. A few gusts to 20 knots may occur mid to late afternoon with some deeper mixing. Outlook...Non-VFR with lake effect rain/snow showers across NE OH into NW PA late tonight through Wednesday. Elsewhere scattered showers should produce non-VFR conditions. && .MARINE... Winds continue to decrease on the western basin of Lake Erie so the Small Craft Advisory has been cancelled west of Vermilion. In addition, water levels have recovered on the western basin of Lake Erie and are expected to remain above the critical mark so the Low Water Advisory has also been cancelled. Previous discussion... Active conditions on the lake will continue the remainder of the weekend and through much of next week as a series of fronts/troughs cross the region. WSW winds of 15-25 knots will continue to generate 5 to 8 foot waves and locally higher (highest in the eastern basin) into tonight. Winds and waves will diminish faster in the western basin, so the Small Craft Advisory west of Vermilion remains on track to expire at 00Z while the Small Craft Advisory for the rest of the nearshore zones continues through 10Z Sunday. Lighter SW winds of 10-15 knots are expected Sunday before veering to W to WSW Sunday night and Monday and increasing to 15-25 knots. This will build waves to 3 to 7 feet, so another round of Small Craft headlines and possibly low water issues in the western basin are expected at that time, continuing Monday night into Wednesday as winds frequently remain in the 15-30 knot range from the W and WNW keeping wave heights elevated. Wind directions in the early to mid week period are less certain than wind speeds, but oscillation between WSW and WNW is expected. Winds and waves will gradually decrease late Wednesday and Thursday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Frost Advisory until 9 AM EDT this morning for OHZ013-014-022- 023-033. PA...Frost Advisory until 9 AM EDT this morning for PAZ002-003. MARINE...None. && $$ SYNOPSIS...MM NEAR TERM...MM SHORT TERM...Garuckas LONG TERM...Garuckas AVIATION...MM MARINE...KEC/Garuckas