textproduct: Cleveland

WHAT HAS CHANGED

A Frost Advisory has been issued for portions of Northwest Pennsylvania as temperatures fall into the low to mid 30s tonight. Patchy frost elsewhere is possible, however clouds cover should inhibit any widespread development across northern Ohio.

KEY MESSAGES

1) Below normal temperature through the weekend pose a risk of frost overnight Thursday through Saturday nights. A warm up is on the way for next week.

2) Multiple chances of light precipitation through Friday. Chance of thunderstorms return next week.

DISCUSSION

KEY MESSAGE 1... A surface trough lingering over the area today into Friday will allow for a much cooler Canadian airmass to push southeast across the entire area. 850mb temperatures associated with this system will drop into the -3 to -5C range, resulting in well below average temperatures at the surface. Highs today through Saturday are expected to only climb into the low to mid 50s. The bigger concern is the very cool overnight temperatures through Saturday night which are expected to fall into the low to mid 30s. These low temperatures could pose a risk to vegetation that has already begun to grow due to the early spring warm up. The biggest uncertainty with the multiple days of potential frost risk is the timing of cloud coverage and how much that inhibits temperatures from falling. Opted to add frost potential through Friday night, however additional concerns are possible Saturday. For tonight, have gone ahead and issued a Frost Advisory for portions of inland NWPA where breaks in the cloud coverage should lend to colder temperatures. Elsewhere in Ohio, cloud coverage ahead of an approaching shortwave should work to inhibit that frost potential, but will continue to monitor conditions today to determine any need for extension further west. People should taken proactive measurements to protect any vulnerable vegetation to these cold temperatures the next three nights.

The good news is these well below normal temperatures are not expected to stick around. By Sunday, a departing high pressure off the East Coast will allow for a southwesterly, WAA regime to develop and the warmer air to return. Temperatures should rebound to near normal for Sunday through much of next week with highs climbing into the 60s and overnight lows dropping into the 40s to low 50s.

KEY MESSAGE 2... This morning, an area of light showers continues to drift east, resulting in areas of reduced visibilities as low as 3SM. These showers should depart to the east by this evening, allowing for a brief period of dry conditions before the next shortwave trough pushes east along the amplified upper level trough and provides enough support for additional shower development late tonight into Friday. Overall mesoscale support will remain minimal with these showers, so have opted to keep the potential of thunder out of the forecast at this point. Highest confidence in some heavier showers will be south of US30, though there are no flooding concerns.

As this upper level trough currently centered north of the area pushes east through this weekend, much of the area should remain dry until another potential trough digs south next week reintroducing the chance of showers and for thunderstorms. From late Monday through Thursday, multiple shortwave troughs embedded within the larger trough will push east providing energy to enhance associated surface lows and support multiple boundaries moving across the area. Given the increase in moisture across the area and warming temperatures, expecting enough instability to present the potential for thunder. However, given how far out these systems are and how much diversion there is amongst models, any potential for severe weather remains very uncertain.

AVIATION /12Z Thursday THROUGH Monday/

Mainly MVFR conditions across the TAF sites this morning associated with low ceilings, though light to moderate rain is also resulting in lower vsbys at ERI. Gradual improvement to VFR is expected from west to east through this morning and afternoon as drier air briefly enters the region. Another area of rain will arrive from the west late tonight into Friday morning, bringing MVFR and perhaps even IFR ceilings and vsbys.

Winds are generally out of the north to northwest this morning, 8 to 10 knots. Winds will favor a northwest direction for much of the day, increasing slightly to 8 to 12 knots with periodic gusts up to 20 knots possible, especially out west. Winds will become light and variable overnight.

Outlook...Non-VFR possible in scattered showers and thunderstorms on Monday.

MARINE

Generally quiet marine conditions are favored through the weekend with no headlines expected. West to northwest winds of 10 to 15 knots today will diminish to less than 10 knots on Friday, with weak winds to continue through Saturday. Slightly stronger offshore flow of 10 to 15 knots will arrive on Sunday, becoming 15 to 20 knots by Monday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...Frost Advisory from 11 PM this evening to 9 AM EDT Friday for PAZ002-003. MARINE...None.