textproduct: Cleveland

SYNOPSIS

High pressure over the area will drift off the Mid-Atlantic Coast by Friday morning as a low pressure system moves northeast through the Great Lakes region towards Quebec on Friday into Saturday. The active pattern will continue as another low pressure will move east out of the central Plains across the area on Sunday with a surface trough lingering into the start of next week.

NEAR TERM /THROUGH FRIDAY NIGHT/

High pressure over the area will allow for plenty of sunshine through sunset tonight with near average temperatures across the area. Low temperatures tonight will drop into the low to mid 30s for areas along and east of I71, remaining a bit warmer in the low 40s for areas west of the corridor.

This high will drift off the Mid-Atlantic Coast tonight into Friday morning as another strong low pressure system moves into the western Great Lakes Region. This low is expected to move a warm front north Friday afternoon, quickly followed by a cold front Friday evening. This system will have strong synoptic support and frontogensis associated with it, resulting in widespread showers likely. Overall instability looks to remain marginal so have opted to keep any mention of thunder once again out of the forecast. QPF totals from rain onset through Friday night are generally between 0.2-0.4 inches, which should not limit any potential flooding concern. In the heaviest showers, there is the potential for localized ponding on roads and reduced visibilities so motorists should use caution. Aside from the shower potential, Friday is expected to be another breezy day. By Friday morning, a LLJ with winds of 45-50 knots will push northeast over the area increasing surface winds from the southwest to 15-20 mph with gusts up to 30 mph possible. This system will be quick moving and winds will weaken as they back behind the cold front Friday afternoon resulting in sustained winds from the west-northwest at 5-10 mph by Friday night. High temperatures on Friday will climb into the mid to upper 50s, possibly touching 60 in the far western counties. Overnight lows will drop into the upper 30s to low 40s.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

The active weather pattern will persist through the weekend as a deepening upper level trough pushes south across the eastern two thirds of the CONUS. Initially on Saturday, a departing low pressure system will result in a surface trough lingering across the area. This will result in the scattered potential for lake enhanced rain showers throughout Saturday, although much of the area should remain dry. By Saturday night, another potent low pressure system will move out of the central Plains into the southern Great Lakes. This low pressure will be support by a strong upper level jet and the center is expected to move east over the CWA. Given the southern extent of this low, a Canadian cold airmass will be able to usher in behind the system and provide the area with the first taste of winter by Sunday night. Widespread rain showers are once again expected late Saturday night through Sunday with a transition to rain/snow mix and eventually all snow Sunday night as 850mb temperatures dive to -5C or cooler. Total rainfall amounts will once again range between 0.2- 0.5 inches with isolated pockets of higher totals possible. Not expecting any flooding concerns with this system either. As discussed, rain will transition to snow Sunday night with a light dusting up to 0.5" possible across the area by Monday morning. These values may be a bit on the high end given the warm antecedent ground conditions, so will have to monitor the snowfall rates and melting rates.

High temperatures on Saturday will climb into the low to mid 50s with cooler temperatures on Sunday as highs only climb into the low to mid 40s. Overnight lows on Saturday will generally be in the 30s before falling into the low to mid 20s Sunday night.

LONG TERM /MONDAY THROUGH THURSDAY/

A first taste of winter will arrive for the start of next week as a cold airmass surges south with 850mb temperatures dropping into the - 8 to -10C range. This will bring below normal temperatures and the potential for the first accumulating snowfall, especially in the snowbelts areas. Focusing first on the snow potential there are some key things to note. The pattern of this system suggests that accumulating lake effect will occur on Monday into Tuesday for portions of the primary and secondary snowbelts. Given the change of temperatures from the surface of the relatively warm lake up to 850mb, expect plenty of lake induced instability to develop with steepening lapse rates. Coupled with enhancement for upsloping inland and surface convergence, some lake effect bands that develop could be rather efficient at times. Models are very consistent in this set-up, so confidence is high at this point that there will be accumulating snow, even with the warm antecedent ground conditions. As this event gets closer and hi-res models can be used there will be a better idea of totals, but based on the current forecast those areas could see 4-6 inches with locally higher amounts possible in the higher elevation. Given this is the first snowfall of the year, expecting impacts on Monday and early Tuesday. Stay tune to the forecast to get the latest updates on timing, impacts, and snowfall totals. In addition to snowfall across the snowbelts, temperatures will also fall into the mid 30s on Monday. Given an enhanced gradients associated with the low pressure, another round of windy conditions is expected which has the potential to bring wind chill values into the upper teens to low 20s. Overnight lows on Monday will be well below average as they fall into the low 20s with wind chill values in the teens.

On Tuesday afternoon, 850mb temperatures begin to gradually warm, allowing for a mix of lake effect rain/snow to develop and eventually transition to all rain. These rain showers will persist through midweek as the area remains in a northwest flow pattern. Only good news is that any additional showers should primarily be rain (with the exception of a few flakes mixing in overnight) which should help to melt any snow that falls on Monday/Tuesday. Highs from Tuesday onwards should be in the 40s to low 50s with overnight lows consistently dropping into the 30s.

AVIATION /00Z Friday THROUGH Tuesday/

VFR conditions will continue across terminals under high pressure through early Friday morning before a cold front arrives from the west and ushers in a period of MVFR conditions in showers. These showers are expected to arrive at western terminals (KTOL/KFDY) by 12Z/Fri and will push east towards eastern terminals (KYNG/KERI) by 17-18Z/Fri. Conditions gradually improve to VFR by the end of the TAF period Friday evening.

Light southerly winds tonight will increase to 5-10 knots early Friday morning. A strong southwesterly LLJ will move overhead allowing for a brief window of LLWS at all terminals, except KERI, through daybreak Friday. Southerly to southwesterly winds increase to 15 to 20 knots with gusts to 25 to 30 knots Friday morning through late Friday night. Winds will gradually diminish to 10-15 knots while turning westerly near the end of the TAF period.

Outlook...Non-VFR in rain showers Saturday night into Sunday as a low pressure system moves through the Great Lakes region. Gusty winds and a cooler airmass expected behind this system with non-VFR possible in areawide snow showers Sunday night and Monday. Accumulating lake effect snow and non-VFR is likely across Northeast OH and Northwest PA terminals Monday and Tuesday.

MARINE

Periods of unsettled marine conditions are expected over the next several days as a series of systems move across the Great Lakes.

After a brief break in headlines, Small Craft Advisories will return to Lake Erie tonight into Friday as low pressure tracks east across the Upper Great Lakes and a cold front advances east towards Lake Erie. South winds 15 to 25 knots will develop late tonight before increasing to 20 to 30 knots by 12Z/7 AM Friday morning. Winds become more southwesterly Friday afternoon and there's a chance of winds in the open waters of the central and eastern basins briefly exceeding 30 knots late morning or early afternoon. With that being said, confidence in gales is too low to warrant a Gale Watch or Warning at this point. Winds will shift to the west/northwest and gradually diminish behind the cold front Friday night and Small Craft Advisories will likely continue east of the Islands as waves slowly subside through early Saturday morning. A period of northwest winds around 10 knots is expected during the day Saturday with flow shifting to the northeast Saturday night.

Winds will once again increase as low pressure moves east across the lake on Sunday with northwest winds to 20 to 30 knots expected on the back side of the low starting Sunday afternoon. Small Craft Advisories will likely be needed through early next week and will need to keep an eye on the potential for gales late weekend into early next week, especially on Tuesday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory from 1 AM to 4 PM EST Friday for LEZ142>144. Small Craft Advisory from 1 AM Friday to 3 AM EST Saturday for LEZ145-146. Small Craft Advisory from 1 AM Friday to 7 AM EST Saturday for LEZ147>149.