textproduct: Cleveland

WHAT HAS CHANGED

No major changes but added a Wind Advisory for the downsloping areas of Erie County PA. Temperatures are non-diurnal for Friday and highs occur earlier in the day prior to frontal passage.

KEY MESSAGES

1) Winds picking up tonight into Friday as rain moves in with a low pressure system moving into the region. Unseasonably warm Friday.

2) A late Saturday/early Saturday night cold front brings rain changing over to lake effect snow Sunday and significantly colder air into the region after the Friday warm up.

DISCUSSION

KEY MESSAGE 1...

An area of low pressure will track from the southern plains region into the central Great Lakes tonight into Friday. A leading edge warm front will move into the western zones of the CWA this evening with weak isentropic ascent producing scattered light rain. Low level/surface warm air advection will dominate the overnight period with temperatures warming up through the morning hours Friday, and then a non-diurnal trend continuing through Friday with the midday passage of the cold front. Temperatures will top out in the upper 50s to near 60F before dropping through the remainder of Friday into the evening. As per typical with these cold season low pressure systems, low level flows will be on the increase, and in the warm sector, a low level jet pushing 75kts is expected. A pressure gradient increase will provide strengthening winds for the area, but a relatively stable boundary layer should keep those higher low level velocities off the surface. A line of convection should be expected ahead of the cold front late tonight into early Friday. While there is not a severe threat, and lightning will probably be on the scarce side with a pronounced lack of instability, this could be a mechanism to bring stronger gusts to the surface. That and the now descending cold air advection in the wake of the cold front will be the primary producers of the wind issues for this part of the forecast. That said, the synoptic scale wind gusts are a touch below 40kts for the area, so no Wind Advisory for now. For the Erie County PA region, southerly downsloping in the warm sector is expected, so this added aspect to the wind should get the gusts to 40-45kts for a few hours, and will go with a Wind Advisory for the lakeshore zone of the county.

KEY MESSAGE 2...

Low pressure develops over the lower Great Lakes in response to a digging/closing upper level low dropping into the western Great Lakes from the Canadian prairies. This cold front moving through as a result late Saturday will knock temperatures back down below freezing once again as we head into the latter half of the weekend. Rain changes to light snow Saturday night in minimal to no accumulations, but then a brief lake effect setup commences for Sunday into early Sunday night as a surface trough lingers and the axis of an upper trough swings through. This is a low end event, and only expecting 1-4 inches for now in the snow belt areas before winds turn southwesterly on Monday.

AVIATION /18Z Thursday THROUGH Tuesday/

At the surface, a ridge exits E'ward from our region through 18Z/Fri. Simultaneously, a potent low wobbles NE'ward from the central Great Plains to near Georgian Bay. Accordingly, a warm front should sweep NE'ward through our region between about 03Z/Fri and 12Z/Fri, while the low's trailing cold front will sweep E'ward and should near KTOL and KFDY by 18Z/Fri. Our regional surface winds will be around 10 to 20 knots during the TAF period and veer from SSE'erly to S'erly to SW'erly with the warm front passage. Winds will gust up to 20 to 35 knots at times, especially after 00Z/Fri. Note: a S'erly to SW'erly low- level jet of about 40 to 60 knots at/near 925 mb will result in low-level wind shear after 00Z/Fri. This jet and associated low- level wind shear should exit E'ward from KTOL, KFDY, and vicinity after about 15Z/Fri.

Widespread dry weather and VFR persist for the time being. Scattered to widespread rain showers and accompanying MVFR ceilings associated with the low pressure system should overspread our region generally from west to east between about 03Z/Fri and about 12Z/Fri. These showers and widespread ceilings should persist through 18Z/Fri and yield VFR to MVFR visibility.

Outlook...Non-VFR expected with periods of rain and/or snow Friday afternoon through this Tuesday.

MARINE

As high pressure passes to the east and a low pressure system enters the Great Lakes region tonight, southerly winds will gradually increase over the lake and eventually reach 15 to 25 kts of flow tonight. The associated cold front of the system will cross the lake on Friday and shift winds to the west then northwest with 15 to 25 kts continuing. This will allow for waves to build over 4 ft for the eastern half of the lake, where conditions are more ice-free. With this system, have issued a Small Craft Advisory for the entire lake for tonight into Friday with the forecast package this morning.

High pressure will be in the region Friday night and early Saturday to allow for a reprieve of strong winds and there will be some easterly flow. A low pressure system will enter on Saturday and pass over the lake. Winds will flip to the west by Saturday night and increase as the low strengthens over the region through Sunday. There will likely need to be additional marine headlines for the weekend. A surface ridge will build over the lake on Monday and shift winds southwest. However, there will still be a strong pressure gradient in the region and 15 to 25 kt winds may continue, as well as marine headlines.

CLIMATE

Unseasonably warm temperatures are expected on Friday with record high temperatures possible. Here are the record high temperatures for area climate sites on January 9th:

Daily Record High Maximum Temperatures

Date Toledo Mansfield Cleveland Akron Youngstown Erie 01-09 59(1880) 61(1946) 66(1937) 63(1946) 66(1937) 64(1937)

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...Wind Advisory from 11 PM this evening to 11 AM EST Friday for PAZ001. MARINE...Small Craft Advisory from 10 PM this evening to 4 PM EST Friday for LEZ142>145. Small Craft Advisory from 10 PM this evening to 10 PM EST Friday for LEZ146-147. Small Craft Advisory from 10 PM this evening to 1 AM EST Saturday for LEZ148-149.