textproduct: Cleveland

WHAT HAS CHANGED

A Winter Weather Advisory has been issued for inland Erie County Pennsylvania from 11 AM Sunday to 1 AM Monday for 3 to 5 inches of snow. Also trended the forecast towards a faster transition from rain to snow on Wednesday afternoon which could have more of an impact on the evening commute.

KEY MESSAGES

1) Winter returns Sunday afternoon with blustery conditions and lake effect snow showers with light to moderate accumulations in the snowbelt.

2) Windy conditions possible Tuesday afternoon.

3) A strong cold front will arrive Wednesday afternoon with an active pattern and below normal temperatures setting up to end the week.

DISCUSSION

KEY MESSAGE 1...

Conditions remain mild this afternoon as surface low pressure tracks northeast across the area ahead of an upper level low diving south across the Upper Midwest. Rain will blossom across the area through this evening as large scale ascent increases. Surface low pressure deepens over Lake Huron tonight with an initial cold front wrapping west to east across the area in the pre-dawn hours. An initial round of scattered snow showers will accompany the front, with the best coverage focused across our southern counties where locally around a half inch of snow is possible.

The upper level trough axis crosses the area on Sunday morning with some semblance of a mid-level dry-slot bringing a break in snow showers during the morning. A secondary cold front arrives at the surface towards midday along with a return of mid-level moisture. Snow showers ramp up quickly during the afternoon on Sunday with reduced visibilities and accumulating snow focused primarily in the snowbelt downwind of Lake Erie. The window for snow will be somewhat brief, only lasting 4-6 hours in Ohio with a little longer duration in Pennsylvania. The Ohio snowbelt will tend to range from 1-3 inches with the highest over the higher terrain in Geauga County with 3 to 5 inches for Erie County Pennsylvania where a Winter Weather Advisory has been issued. There will be some component of snow squalls during the afternoon with winds gusting between 30 to 40 mph and reduced visibilities below 1 mile at times. Wind chills will be feel much colder as they drop into the teens.

The upper trough swings through fairly quickly and moisture will dry out at 700mb in Ohio by 00Z while moisture downwind of Lake Huron along with northwesterly upslope flow will maintain snow showers into the evening in NW Pennsylvania. Intensities will drop off significantly though and additional accumulations will tend to be an inch or less during the evening.

KEY MESSAGE 2...

Temperatures rebound Tuesday as southwesterly flow ramps up ahead of the next trough moving into the upper midwest. A warm front lifts north on Tuesday with a tightening surface pressure gradient. A low level jet with speeds of 40-50 knots will pass overhead at 850mb but mixing depths are only forecast to reach about 2K feet. Winds gusts of 30-40 mph are expected in the warm air advection regime with temperatures reaching 40-45 degrees.

KEY MESSAGE 3...

Following the warm up on Tuesday, a strong cold front will cross the area on Wednesday with rain transitioning back to snow showers. Trended faster with bringing the colder air in Wednesday behind the cold front which will result in primarily snow by late afternoon. Some spread remains among the long range models with respect to the evolution of the upper level trough. The 12Z/10 GFS and ECMWF depict a slower upper level trough that extends all the way to the Tennessee Valley with more directional shear over Lake Erie while the Canadian favors a more consolidated upper level trough that is east of Lake Erie by 06Z Thursday and more supportive of lake effect snows.

Both of these solutions maintain below normal temperatures through the duration of the long term forecast. The GFS and ECMWF try to develop a swath of more organized snow across Pennsylvania on Thursday as that southern piece of energy curls northeast. Confidence is low on any particular storm track this far out as models struggle to get a handle on the long range but opportunities for lake enhanced snows will continue with considerable ice-free areas on Lake Erie.

AVIATION /00Z Sunday THROUGH Thursday/

Mixed-bag of MVFR and IFR across the TAF sites this evening, associated with both lower vsbys and ceilings in rain. Conditions may briefly improve to VFR out west overnight, before deteriorating to MVFR and IFR late tonight into Sunday in snow and low ceilings. The highest confidence for IFR and perhaps brief LIFR vsbys late tonight into Sunday morning will generally be south of the I-90 corridor as a disturbance quickly moves east through the area. Another round of snow will arrive from the north and northwest with a trough late Sunday morning and afternoon, bringing reduced MVFR and brief IFR vsbys across the entire area.

Winds are favoring a west direction this evening behind a cold front, 10 to 15 knots with gusts up to 25 knots. Winds will slightly diminish overnight, 10 to 12 knots, before increasing out of the west to northwest behind a trough Sunday afternoon, 15 to 20 knots with gusts up to 32 knots.

Outlook...Non-VFR possible in rain/snow showers Tuesday and Wednesday, with lake effect snow showers possible in NE OH and NW PA on Thursday.

MARINE

Another high wind event will impact Lake Erie tonight and Sunday, with the strongest winds expected on the central and eastern basins, as low pressure organizes over the central Great Lakes this evening and moves into the eastern Great Lakes by Sunday morning while modestly deepening. WSW winds will first increase to 20-30 knots as the cold front crosses the lake tonight, further increasing to 25-35 knots from mid Sunday morning through the afternoon while turning WNW behind a secondary cold front. This will build wave heights to 9 to 14 feet in the central and eastern basins. Gale Warnings remain in effect from 00Z Sunday through 00Z Monday from Avon Point to Ripley, with Small Craft Advisories farther west over the rest of the nearshore waters.

WNW winds will diminish to 10-20 knots Sunday night while quickly turning SW by Monday morning. This will set up another period of strong SW winds as another low crosses the northern Great Lakes Monday, with corresponding SW winds increasing to 15-30 knots.

Briefly quieter conditions are expected Monday night before another storm system impacts the region mid week. SSW winds will increase to 15-30 knots Tuesday, turning NW behind a strong cold front by Wednesday afternoon. NW winds of 10-20 knots will then continue through Thursday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...Winter Weather Advisory from 11 AM Sunday to 1 AM EST Monday for PAZ002. MARINE...Small Craft Advisory until 7 PM EST Sunday for LEZ142-143. Small Craft Advisory until 10 PM EST Sunday for LEZ144-145. Gale Warning until 7 PM EST Sunday for LEZ146>149-166>169.