textproduct: Cleveland

WHAT HAS CHANGED

The timing for any rain and minor wind impacts in the area from Hurricane Isaias has slowed a bit with most of the impacts occurring on Sunday.

KEY MESSAGES

1) High pressure across the region will allow for dry conditions to continue with slowly increasing temperatures. Overnight frost chances will remain low with moderating nightly temperatures.

2) Rain and elevated wind gusts are expected on Sunday with the remnants of Hurricane Isaias moving through the Ohio Valley. Any flooding concerns will be extremely localized given the recent dry spell and limited to the southeastern portions of the forecast area.

DISCUSSION

KEY MESSAGE 1... High pressure will continue to build over the area today and last through Saturday, allowing for dry conditions through the first half of the weekend. With high pressure overhead and light flow across the region, temperatures will dip into the 40s and some upper 30s in sheltered locations but frost potential will be low with highs in the 60s and 70s this afternoon. As high pressure shifts to the east on Friday and Saturday, southerly flow and warm advection into the region will allow for temperatures to get a bump into the 70s and maybe some 80s for Saturday with increasing nightly temperatures.

One minor concern through end of the week will be dry conditions during the afternoon hours with relative humidity values in the 25-40% range for most areas with peak afternoon heating and mixing. Given the recent dry spell for much of the area, fuel moisture is on the lower end, especially in Northwest and Central Ohio. Given this and marginally conducive weather conditions, there could be some fire spread concerns if a fire were to develop. However, all conditions with the weather and fuels remain too marginal for a headline or even a Special Weather Statement.

KEY MESSAGE 2... The main weather concern for the forecast period will be what happens with Hurricane Isaias in the Gulf of America. Isaias will move north and make landfall along the Gulf Coast on Friday night. The main circulation will slow in the Tennessee Valley this weekend, but the moisture from the system will be picked up by the flow aloft, allowing for rain to spread north ahead of the center of the circulation. This would allow for rain to enter the forecast area after Midnight on Saturday night, continuing through the day on Sunday. Winds will increase on Sunday with the advancing remnant low with gusts of 30-40 mph possible. Total rainfall will be variable across the forecast area with the potential for a sharp gradient of rainfall depending on where the main rainfall axis aligns. Areas of Northwest Ohio may struggle to see a quarter inch of rain or so, whereas southeastern areas could see over an inch and locally higher approaching 1.5-2 inches. Given low river flows and the recent dry pattern, flooding will be localized and nuisance at worst over the local area.

AVIATION /18Z Thursday THROUGH Tuesday/

VFR conditions are expected to continue through this TAF period. Winds this afternoon will be from the west-northwest at 10-12 knots, occasionally gusting up to 20 knots. Once the sun sets, winds will weaken to light and variable and persist through the end of the period. A SCT cu field with bases between 4-6kft has developed across the eastern portion of the area, resulting in FEW to SCT cloud decks this afternoon but once the sun sets, conditions will stabilize and clear skies will persist.

Outlook...Non-VFR is possible with rain showers on Sunday.

MARINE

Brisk west to northwest flow continues over the eastern half of Lake Erie with winds of 15 to 20 kts and waves in the 3 to 5 ft range. Will maintain part of the Small Craft Advisory for the eastern basin but will chop off the western portion of the advisory as winds and waves have been less problematic in Ohio. High pressure building into the region will continue to decrease flow for Friday, allowing a pleasant marine weather day. High pressure will push east for Saturday and southerly flow will be expected. This southeast flow will increase for Saturday night into Sunday with the approach of the remnants of Hurricane Isaias. Winds will shift to the northwest with the passage of the remnant low on Monday. There is potential for a Small Craft Advisory to be needed for the remnants of Isaias on Sunday into Monday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for LEZ146. Small Craft Advisory until 8 PM EDT this evening for LEZ147>149.