textproduct: Cleveland

WHAT HAS CHANGED

The likelihood of afternoon convection is decreasing due to widespread cloud cover and lack of instability. As of now, it appears that the best chance of severe weather will occur in the southern part of the local area this evening, although it's possible that the majority of the strong to severe storms remain to the south/southeast of the local area.

KEY MESSAGES

1.) Isolated to scattered strong to severe storms possible primarily in the southern portion of the forecast area this evening.

2.) Variable temperatures expected for most of the week with periodic precipitation chances occurring tonight and mid to late week.

DISCUSSION

KEY MESSAGE 1... A cold front will continue to move southeast across the local area this afternoon. Showers are likely along the cold front this afternoon, although widespread cloud cover, dry air, and lack of instability will likely hinder any thunderstorm development. The best chance of storms will likely be along the southeastern border or to the southeast of the local area, but thunderstorms will likely hold off until later this evening.

Confidence in convection is slightly higher for this evening, although once again there's still uncertainty in where storms will initiate. Showers and thunderstorms are expected to develop behind the cold front at around 8 PM this evening before exiting to the southeast by midnight, however mid-level dry air may once again inhibit convection development. There's also a chance that storms develop near the southeastern border of the CWA and strengthen after exiting the CWA. The best instability will likely be in the southern half of the local area, primarily from U.S. Route 30 south. There will be a sharp cutoff in shear values close to the lakeshore, however 0-6km shear values of 30-40+ knots support storm mode of a more organized line or supercells. At this point, instability will be elevated and lapse rates are relatively high so large hail will be the primary hazard, although surrounding upper air soundings suggest that dry low-level air could produce a risk of downbursts/damaging wind gusts. Will need to keep a close eye on mesoanalysis/satellite data over the next several hours and will make adjustments to the forecast as needed. Either way, there is a Slight Risk (level 2 of 5) for severe weather along and south of a line from roughly Marion to Warren, OH with a Marginal Risk (level 1 of 5) north from roughly Findlay, OH to Meadville, PA (including Cleveland). The best potential for severe weather will be in the Enhanced Risk area to the southeast of the forecast area.

KEY MESSAGE 2... Cold air advection and lingering troughing over the Lower Great Lakes will result in low-end chances of light snow showers across NE OH and NW PA late tonight through Monday afternoon, although accumulations beyond a dusting on grassy/elevated surfaces are not expected. From there, dry weather is favored Monday night through early Wednesday evening as high pressure builds over the region. Periodic showers are likely as the next system approaches and crosses the region late Wednesday through Thursday evening. A few thunderstorms are possible with cold front passage on Thursday or Thursday night, but still quite a bit of uncertainty with frontal passage timing and the resulting precipitation chances. Dry weather is favored for the weekend.

Temperatures will fluctuate quite a bit during the week with the coldest high temperatures in the upper 30s and lower 40s anticipated Monday/Friday and the warmest highs in the 60s and lower 70s anticipated on Thursday.

AVIATION /18Z Sunday THROUGH Friday/

As a strong cold front moves across the area this afternoon, winds from the north at 10-14 knots will begin to gust up to 20 to 25 knots. Showers and some thunderstorms are expected to develop this afternoon into the early overnight hours, especially across the southern portion of the area. There should be an initial push of convection early this afternoon before a more defined line pushes southeast around 00Z. Opted to handle t'storm and precipitation chances with TEMPOs given the uncertain timing at each terminals. Localized stronger gusts may be possible with these storms, but the primary concern/hazard is large hail. Showers/storms will end from northwest to southeast near midnight, becoming dry overnight. Winds will begin to shift and gain a more northwesterly component at 5-10 knots with isolated gusts up to 20 knots still possible. With this system, expected widespread VFR conditions this afternoon to give way to IFR conditions overnight as ceilings lower behind the departing front. Monday morning, things should gradually begin to improve with ceilings lifting to higher than 1kft.

Outlook...Non-VFR in stratus and perhaps a few lake effect flurries or snow showers possible late tonight into Monday. Additional non-VFR conditions possible Wednesday into Thursday as another low pressure brings showers to the area.

MARINE

A cold front continues to slowly drift south across the are this afternoon, allowing winds across Lake Erie to become northerly at 10 to 20 knots. The strong winds remain isolated to the western basin right now. As the cold front moves further south, winds will gain more of a northwesterly component with winds up to 20 knots spreading east across the central basin. This gustier onshore flow will result in waves building to 3-5 feet across the central basin late tonight into early Monday morning. As a result, a brief Small Craft Advisory has been issued to highlight this hazard.

As the parent low moves off the Mid-Atlantic Coast on Monday, northwest winds will weaken to 10-15 knots. High pressure builds over the region Tuesday, shifting winds once again to be from the south-southwest at 5-10 knots which will persist through much of Wednesday. Another low pressure system is forecast to move east through the region Thursday into Friday, increasing winds to 15 to 20 knots once again. This period will need to be monitored for any additional marine headlines.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...None.