textproduct: Cleveland

WHAT HAS CHANGED

There are a couple minor changes and noteworthy forecast adjustments to address with this morning update. There may be a low potential for an isolated strong storm or two to develop this afternoon across northern Ohio. The other forecast change is regarding drier weather is now expected for Memorial Day on Monday. The rest of the forecast from the previous update has not changed in an impactful way.

KEY MESSAGES

1.) Two rounds of showers and isolated thunder is expected today through Sunday evening. Much of the area will see a soaker this weekend with moderate to locally heavy rainfall of 1.0 to 1.5 inches.

2.) A warmer and drier weather pattern will begin to take shape over the Great Lakes and Upper Ohio Valley starting Monday. This summer-like weather will continue for much of next week.

DISCUSSION

KEY MESSAGE 1... The first of two weather systems that will impact our Memorial Day Weekend has arrive early this morning with widespread rain showers and breezy conditions. A weak low pressure system is currently tracking northeastward across the Upper Ohio Valley this morning. This weather system has a rather high tropical moisture content in the atmosphere to work with as it moves through today and evening. The forecast hasn't changed much from the previous updates. We are expected the highest POPs to be this morning and areawide coverage. The rain showers and possible isolated thunder will become most scattered in nature by late morning or midday but POPs will remain in the moderate to higher range. The track of this surface low will lift across the western basin of Lake Erie this afternoon. A rather stout southeasterly low level flow and breezy conditions will continue east of this low pressure for much of today over NEOH and NWPA. There will be several hours later today of possibly elevated gusty winds with a downsloping effect across the immediate lakeshore zones of NEOH and especially Erie County PA. Wind gusts may be up to 45 mph possible late today into early this evening. Rainfall amounts of 1.0 to 1.5 inches are expected areawide today through Sunday evening. Some minor water level rises may be possible on area streams and drainage basins due to the heavier rainfall this weekend.

There is one forecast adjustment and note worthy update to convey in regards to this afternoon. There is a low potential for an isolated strong or two that could develop ahead a weak surface trough/boundary over north central and northeast Ohio. As the surface low lifts northeast into southern Ontario late today, it does appear that some scattered low top convection that will develop along a trailing weak surface trough. This atmospheric setup later today is similar to a very tropical environment with just enough 0-6KM shear around 30 knots and storm relative helicity values up to 150 m2/s2. With that said, SPC has mentioned a very low 2 percent probability for an isolated brief tornado risk in their latest outlook today. It will be something that we will monitor as the potential is very low but not zero given this setup this afternoon. The timing of the scattered convection to keep an eye on will be between 12 pm and 6 pm, generally moving across northern Ohio from west to east.

Today's storm system will move out later this evening with rain chances decreasing areawide overnight. There will be a lull in POPs late tonight through Sunday morning or midday. The next weak surface trough will move in from west to east later on Sunday into the evening bringing a second round of showers and isolated thunder. This system will be more progressive and not as widespread with coverage of showers. Rainfall amounts will be light around a quarter of an inch or less for most locations. That 2nd weather system will move out of the area late SUnday night.

KEY MESSAGE 2... There is some better news in regards to a forecast change on Monday and this Memorial Day. The forecast is looking nicer and drier with fair weather expected for outdoor activities. High pressure will build in over the region starting Monday. Skies will eventually clear out from west to east on Monday becoming partly cloudy along with warmer temperatures. Monday's afternoon highs will be in the upper 70s to lower 80s areawide. The model guidance still in fair to good agreement that an Omega block like weather pattern will develop over the north central U.S. and build into the Great Lakes region through much of next week. This pattern should favor much warmer temperatures and mostly drier forecast. High temperatures will climb into the lower and middle 80s for several days by the middle of the week. Some scattered diurnal driven showers and convection may sneak back into the forecast late next week or weekend. But overall, it will start to feel and look more like summer next week.

AVIATION /12Z Saturday THROUGH Wednesday/

IFR to low MVFR ceilings are observed across the region as rain showers move north. The showers will persists through the morning with a break midday today that will help improve ceilings up to MVFR for most sites. There will be a chance for a thunderstorm across the southeastern terminals of KCAK and KYNG this afternoon as a cold front pushes through the region. By early Sunday morning, there is guidance showing LIFR conditions across much of central into northern Ohio, though have opted to use a low IFR ceilings for this TAF issuance.

Winds across the region are out of the southeast at 10-15 knots and gusting to 20-25, with the higher gusts across the eastern terminals. Winds for the western terminals will be lighter as they will be underneath the surface low as it moves north. Those will shift to be out of the south- southwest as it pass this afternoon. Elsewhere, gusty winds are expected to continue through the TAF period and shift to be more out of the south by this afternoon.

Outlook...Non-VFR expected late Sunday into early Monday.

MARINE

Small Craft Advisory will continue for the western half of the lake until 10AM this morning as the low pressure system tracks across that portion and winds begin to subside. An additional Small Craft Advisory has been issued for the eastern half of the lake until 4AM Sunday as southerly winds will downslope creating winds of 20-25 knots. With offshore flow, waves in the nearshore will be 2-4 feet and 3-6 feet in the open waters. High pressure will build into the region throughout the day Sunday and winds and waves will begin to subside as a response. Expect light and variable winds with waves 1 foot or less through mid week.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement until 10 AM EDT this morning for OHZ003-007-009-010. PA...None. MARINE...Small Craft Advisory until 10 AM EDT this morning for LEZ142>145. Small Craft Advisory until 4 AM EDT Sunday for LEZ146>149.