textproduct: Cleveland

WHAT HAS CHANGED

No major changes but confidence in accumulating snow later this weekend increases along with below zero temperatures Friday night and Saturday morning.

KEY MESSAGES

1) Cold front comes through later this evening followed by another tonight brings more light snow, mainly eastern CWA.

2) Early Thursday night cold front brings a significant airmass change with prolonged cold conditions to the CWA through early next week.

3) Accumulating snow potential for the weekend is gaining confidence as a major winter storm system track keeps trending gradually northward.

DISCUSSION

KEY MESSAGE 1...

In the warm sector lull for light snow for much of the area this afternoon, but a cold front coming through this evening and a second one tonight will continue to provide chances for snow showers, most numerous for but not limited to the eastern half of the CWA. There is not too much of a lake component with this snow shower activity given the near parallel winds to the shoreline of Lake Erie as well as much of the lake now covered with ice except for some open waters in the eastern basin. As the pressure gradient tightens with the passing cold fronts over the next 12 to 18 hours, wind gusts should increase into the area of 30kts. Brief time in the warm sector today is bringing temperatures into the mid 30s, but this brief time frame of temperatures above freezing is all that we will see for the remainder of the 7 day forecast. No changes to the Winter Weather Advisory for our PA counties, and overall snow amounts will be manageable.

KEY MESSAGE 2...

The third in line of a succession of cold fronts will be the one that changes the airmass back to well below normal conditions in terms of temperatures for several days. 850mb temperatures plummet into the mid -20s Celsius with a 1044mb high pressure system moving into the Great Lakes. Temperatures begin their sharp drop Thursday night after frontal passage with Friday temperatures likely falling through the afternoon into the single digits. With high pressure over the region, only cirrus clouds will prevent the most efficient radiational cooling conditions Friday night as winds go nearly calm by Saturday morning. Some snow left on the ground will provide the assist for temperatures dropping below zero by Saturday morning, even near the lakeshore where a primarily frozen Lake Erie will no longer be able to keep those areas significantly warmer. Saturday temperatures likely in the 5-10F range CWA-wide, but then slight improvement into Sunday with a winter storm system but a northward push of slightly modified conditions compared to the previous couple of days where 20F may be achievable. Back into the teens Monday and Tuesday with lows consistently in the single digits from Saturday night through Monday night. Monday night could drop back below zero once again in the outlying areas with a fresh snowpack expected.

KEY MESSAGE 3...

All eyes on a major winter storm that will develop over the southern tier of states Friday into Saturday, and affect our area Saturday night through roughly early Monday. The long and short of it is operational long term models keep trying to trend it fruitier northward than previous runs, but not yet in any sort of full agreement, and there will be an important player for the southern Great Lakes in the form of a northern stream upper level trough dropping in from the Canadian prairie region. Not going to get too specific into anything just yet in terms of snowfall amounts or timing as the pieces continue to come together. Arctic air already in place keeps all precipitation snow for the CWA, but with a northward trend, the max temperatures for Sunday may go from 15-20F to more like 20-25F, but will need to keep watching this. The orientation of the upper level trough and the timing of it and whether or not it will phase with the surface low that will move northeastward from the Gulf Coast to the western side of the Appalachians will be a significant aspect of this forecast. If it does so, this will lead to a higher confidence in higher snow amounts for the region, and if not, the surface low will likely fill fairly quickly in the upper Ohio Valley as the system transitions to a coastal low dominant scenario, still some snow, but not as much. It is important to note that the long range ensembles remain conservative with snow amounts for now. Regardless, as mentioned above, more cold air behind this winter storm system for early next week.

AVIATION /00Z Thursday THROUGH Monday/

A mix of VFR and MVFR conditions will continue across the region this evening as a cold front moves through and allows for snow showers to pick up across NE OH and NW PA. There will be a better push of snow through 06z in some of the terminals and there could be some brief IFR conditions, primarily KERI, but a non-zero chance at KCLE and KYNG. A broader push of MVFR ceilings will build in behind this front tonight with most terminals getting ceilings below 3000 ft. High pressure will build in on Thursday and allow for ceilings to scatter out from southwest to northeast. Winds will start south ahead of the cold front and veer to the southwest then west with the frontal passage. Wind gusts of 20 to 30 kts will be expected through Thursday afternoon.

Outlook...Non-VFR possible in lake effect snow showers in NE OH and NW PA through Friday. Non-VFR possible late Saturday through early Monday in widespread snow showers.

MARINE

As of early this morning, satellite passes show that Lake Erie is mostly ice covered outside of a portion of the eastern basin in the open waters from Conneaut eastward. There has been southerly to southwesterly flow throughout the day today and along with warming temperatures just above freezing that may cause any ice not fasten against the nearshore to drift into the open waters. Winds across the lake will be gusting from 15-25 knots out of the southwest through this evening and will increase overnight approaching gales in the central and eastern basins. Winds will begin to subside from west to east Thursday evening back down to 15-25 knots with winds near 30 knots across the far eastern portion of the lake. With the strong winds, there is potential that the water levels near Toledo could drop down near critical levels. Will need to monitor overnight tonight through Thursday. Wave heights in the open waters and ice free zones will be rough building to near 9 feet on Thursday before subsiding through Friday into Saturday down to less than 2 feet.

Starting this weekend, a strong, arctic high pressure system will move across the region and winds will be 10-15 knots through Monday afternoon. Winds will increase again as a low pressure system moves to the south of the lakes and winds will shift from being out of the east on Sunday, to out of the west by Monday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...Winter Weather Advisory until 7 AM EST Thursday for PAZ001>003. MARINE...None.