textproduct: Cleveland

WHAT HAS CHANGED

Forecast remains on track with no changes to heat headlines.

KEY MESSAGES

1) High pressure continues to build to the south east with hot and humid conditions expected through the end of the week.

2) The upper level ridge begins to break down late this week and precipitation chances will return to the region.

DISCUSSION

KEY MESSAGE 1... The upper level ridge continues to build across Eastern CONUS this afternoon with surface level high pressure building across the Ohio Valley. This will bring persistent west to southwesterly flow across the region resulting in 850mb temperatures around 20-24C. Similar to the past few model runs, the NAM has been the warmest with 850mb temperatures up to 26C by Wednesday evening. Currently, Wednesday and Thursday are expected to be the hottest days of the week with multiple areas contesting 100 degrees. Dew points are trending a few degrees lower than they are today which will help with warmer air temperatures. Regardless, heat indices will still be over 105 for much of the area today through the end of the week. Friday has been trending drier as precipitation has slowed down to be into Saturday keeping Friday's heat indices elevated as well. Overnight temperatures will provide little relief as lows will only get down into the mid to upper 70s. This will increase any heat related risks along with the duration of the heat lasting through the end of the week. Heat headlines are valid through Thursday evening, though it is possible to see headlines be extended into Friday.

Late Friday night into Saturday, the upper level ridge begins to break down and the surface high will retreat to the southeast. Flow will become more zonal over the Great Lakes region which will help regulate temperatures into the weekend. Highs will still be above average with warm overnight lows as well, but should fall below advisory criteria.

KEY MESSAGE 2... The upper level ridge will begin to break down late this week into the early weekend and precipitation chances will return to the region. There's still quite a bit of uncertainty regarding the extent of the surface high retreating to the southeast and the timing of it. Models have trended slower over the past few runs with the latest NAM and GFS keeping the ridge axis further to the west than previously. Will need to continue to monitor as we get closer for potential for severe weather as it's possible thunderstorms will track along the upper portion of the ridge. On Friday, with the slower exit of the high, there will be potential for some lake enhanced showers, though confidence is low at this time. On Saturday, models depict a shortwave moving across the Great Lakes region bringing increased showers and thunderstorm potential. Given the water loaded environment, there will be heavy rain potential as well. As mentioned above, still a lot of uncertainty on most aspects of this feature at this time.

AVIATION /00Z Wednesday THROUGH Sunday/

VFR will continue through the TAF period. Lingering FEW-SCT cumulus around 4,000 feet will dissipate this evening and re- develop Wednesday afternoon. Winds will remain southwest, subsiding to under 10kt tonight and increasing to 8-15kt with a few gusts to 20kt Wednesday.

Outlook...Low risk for thunderstorms Thursday evening. Greater potential for scattered storms Friday through Sunday, especially during the afternoon and evening hours each day.

MARINE

Southwest flow around 10 knots expected through at least Saturday morning. A lake breeze is expected each afternoon east of Cleveland, which could result in some better onshore flow and choppiness (closer to 2 ft waves) during the afternoon hours.

CLIMATE

Hotter and more humid weather is expected through Friday. Record warm high temperatures may be challenged. Here are those records for each of our climate stations:

Date Toledo Mansfield Cleveland Akron Youngstown Erie 06-30 97(1953) 94(1970) 95(1941) 96(1913) 94(1942) 92(1930) 07-01 98(1931) 98(1931) 95(2002) 97(1931) 96(1931) 94(2018) 07-02 98(2011) 97(1931) 97(1954) 98(1931) 98(1931) 94(1963) 07-03 100(1911) 93(2020) 98(1949) 97(1911) 98(1898) 93(1934)

CLE WATCHES/WARNINGS/ADVISORIES

OH...Extreme Heat Warning until 8 PM EDT Thursday for OHZ003- 006>014-017>023-027>033-036>038-047-089. PA...Heat Advisory until 8 PM EDT Thursday for PAZ001>003. MARINE...None.