Area Forecast Discussion

WHAT HAS CHANGED

We have cancelled the Heat Advisory due to some slightly drier air that has moved into the area this afternoon. We have a round of strong to severe storms exiting our far eastern Ohio and northwest Pennsylvania counties this mid afternoon. We may see one more round of showers and storms late this evening into the overnight with a cold front.

KEY MESSAGES

1) Scattered showers and thunderstorms will be possible again late this evening into the overnight ahead of an approaching cold front.

2) Slightly cooler and drier weather will move in behind the cold front Friday through Saturday. Pleasant temperatures and lower humidity will continue into next week.

DISCUSSION

KEY MESSAGE 1... A mid level shortwave disturbance is currently tracking across far NEOH and NWPA this afternoon which has helped flared up scattered strong to severe convection over our far eastern counties. The threat for storms with this initial round of convection is just about to completely move out of NWPA and will likely expired the severe storm watch here shortly. In the wake of this mid level disturbance, some drier air has mixed down from the upper atmosphere with dewpoints in the lower to middle 60s across much of northern Ohio this afternoon. Temperatures are also slightly cooler ranging from the upper 70s over NEOH to the upper 80s over NWOH. We have cancelled the Heat Advisory this afternoon due to that slightly drier air mixing down which is keeping the heat index in check. If you have plans for the rest of the afternoon and early evening, the weather should be fairly quiet for the time being as we are in a lull in between areas of convection.

The next and most likely the final round of showers and thunderstorms that could impact our area will be sometime late this evening into the overnight, possibly lingering into the very early hours of Friday morning. This round of showers and possible storms will be just ahead of the approaching cold front that will move through the area early Friday morning. The atmosphere may recover just enough ahead of the shortwave disturbance later tonight to maintain a marginal to slight risk for severe storms overnight. The better potential for additional strong to severe convection would favor NWOH later this evening into tonight. We will be watching the disturbance and complex of convection near Chicago at this time as it moves eastward towards NWOH late this evening. The main threat with any strong to severe storms tonight will be damaging wind gusts. The overall trend for convection tonight will be a weakening as it moves from west to east. Some lingering showers and isolated storms may still be over our far NEOH and NWPA counties around daybreak Friday morning, slowly moving eastward and out of the area.

KEY MESSAGE 2... High pressure will build in later Friday through Saturday across the region with slightly cooler, more comfortable temperatures. High temps on Friday will be in the upper 70s to lower 80s with lower humidity levels. Friday night low temperatures will be pleasant in the upper 50s to lower 60s. Saturday will bring more sunshine and fair weather with highs back into the lower and middle 80s. The overall weather pattern will change with a large, broad upper level trough developing over the Great Lakes region later this weekend into next week. A cold front will move through the area late Saturday night through Sunday with a chance for scattered showers and thunderstorms. Temperatures SUnday afternoon will be knocked back down into the upper 70s to around 80 degrees. High pressure and a fair weather day is expected on Monday with highs in the lower to middle 70s. The next chance for rain will arrive by middle of next week with a low pressure system and cold front. Temperatures will remain in the middle 70s to lower 80s going into next week.

AVIATION /00Z Friday THROUGH Tuesday/

VFR conditions are expected the rest of the daylight hours. We are watching a line of thunderstorms in eastern Illinois. These storms are expected to travel east, reaching the I-75 corridor around 12 AM or so. Most model guidance has this line of storms weakening quickly right around the time it gets to the I-75 corridor. Thunderstorms with sub-severe wind gusts are likely at KTOL/KFDY (probably in the 30-40 knot range) with current expectations for little to no lightning at other TAF sites (though we will continue to monitor trends). Brief MVFR/IFR ceilings/visibilites will be possible as well.

A brief period (2-4 hours) of MVFR ceilings are expected following the showers and storms before conditions become VFR for the rest of the TAF period.

South to southwest winds less than 10 knots are expected through the next few hours. Following the line of showers and storms, the cold front swings through with west winds increase to around 12 knots and gusts to 20-25 knots.

Outlook...Scattered showers and thunderstorms with non-VFR are possible this Sunday and Tuesday.

MARINE

A Small Craft Advisory and Beach Hazards Statement have been issued for overnight tonight into at least late Friday morning. Please click on the weather alert map on our homepage (weather.gov/cle) for the details. A high pressure ridge continues to exit E'ward before a cold front sweeps E'ward across Lake Erie tonight through early Friday afternoon. This front passage will be in response to a deepening low that should track from near the western Great Lakes to near James Bay. Ahead of the cold front, primarily S'erly to SW'erly winds initially around 5 to 15 knots are expected to freshen to 15 to 25 knots overnight tonight and then veer to W'erly to NW'erly in response to the cold front's passage. Behind the front, W'erly to NW'erly winds should ease quickly to around 10 to 20 knots Friday afternoon through sunset Friday evening as a ridge builds from the Upper Midwest and vicinity. Waves of mainly 3 feet or less are expected, but waves as large as 4 to 7 feet are forecast for a time overnight tonight through late Friday morning farther west and into the afternoon farther east.

Overall, quieter marine weather conditions (i.e. winds no greater than 15 knots and waves no larger than 3 feet) are expected Friday night through this Tuesday as primarily high pressure ridging affects Lake Erie. However, on Sunday, SW'erly winds around 15 to 20 knots are expected to veer to NW'erly as a cold front sweeps SE'ward across Lake Erie. As a result, waves as large as 4 to 5 feet are expected and another Small Craft Advisory will likely be needed.

CLE WATCHES / WARNINGS / ADVISORIES

OH...Beach Hazards Statement from 2 AM EDT Friday through Friday morning for OHZ007-009. Beach Hazards Statement from 2 AM EDT Friday through Friday afternoon for OHZ010-011. Beach Hazards Statement from 5 AM EDT Friday through Friday afternoon for OHZ012-089. PA...Beach Hazards Statement from 5 AM EDT Friday through Friday afternoon for PAZ001. MARINE...Small Craft Advisory from 2 AM to 11 AM EDT Friday for LEZ142>144. Small Craft Advisory from 2 AM to 2 PM EDT Friday for LEZ145- 146. Small Craft Advisory from 5 AM to 5 PM EDT Friday for LEZ147>149.