textproduct: Cleveland

WHAT HAS CHANGED

Relative humidiy has trended down across portions of the area today and Friday. Confidence has increased in rain on Sunday and have lowered high temperatures.

KEY MESSAGES

1) Dry fall weather expected today through Saturday. Low relative humidity and breezy winds in Northwest Ohio will result in elevated fire weather concerns for this afternoon.

2) The remnants of Hurricase Isaias will bring widespread rain to most of the area late Saturday night through Sunday.

DISCUSSION

KEY MESSAGE 1... Dry northwest flow conditions expected today in the wake of a cold front that crossed the area Wednesday evening. High temperatures today will average about 10 degrees cooler than the previous day. Surface high pressure will start out over the Upper Midwest this morning before gradually building into Ohio this evening. The pressure gradient will support breezy northwest winds, gusting to 15-20 mph this afternoon. In addition, relative humidity will tend to drop to 25-30 percent in Northwest Ohio which could support fire spread if any were to develop. Fuels are considered to be a little too wet to need a fire weather headline. The flow off Lake Erie will keep humidity values slightly higher across the eastern half of the forecast area.

High pressure and clear skies tonight will allow for good radiational cooling. Inland temperatures will drop to the lower 40s and can not rule out a couple of the typically cooler spots reaching the upper 30s. This should be just slightly too warm for frost formation. Temperatures will trend warmer Friday into Saturday as the upper level trough moves off the New England Coast and the upper level ridge expands north into the Ohio Valley. Several areas across Northwest Ohio and over to Cleveland could reach 80 degrees on Saturday.

KEY MESSAGE 2... Hurricane Isaias has developed in the Carribean and is forecast to track north to the Alabama Coast by late Friday. The system will weaken after making landfall but is expected to track slightly northwest towards the Mid-Mississippi Valley on Saturday as strong high pressure remains over New England. Moisture associated with this system will spread north ahead of the low, with rain beginning from south to north across the local area late Saturday night into Sunday morning. At this time the heaviest swath of rain is forecast to be along and south of Route 30. Forecast rain amounts range from a half inch towards Toledo to just over an inch closer to Central Ohio. There will also be a low end threat of thunderstorms across mainly Central and Northeast Ohio. We will need to keep an eye on downsloping winds towards Erie, PA ahead of this system which could exceed 35 mph, depending on the track of the system. We will continue to monitor rainfall potential but at this time flooding is not expected. Given the fairly widespread nature of the rain, trended high temperatures down a couple degrees for Sunday. We will see a mid-level dry slot try to wrap north into the system on Sunday afternoon which could reduce the coverage of showers. Pops remain into Sunday night for all but extreme Norhwest Ohio.

AVIATION /06Z Thursday THROUGH Monday/

VFR is expected through the TAF period. Winds will generally be out of the west at 5 to 10 knots early this morning before becoming more northwesterly and increasing to 8 to 14 knots with gusts to around 20 knots by late morning/early afternoon. Expect winds to diminish below 10 knots near or shortly after 00Z Friday.

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

MARINE

West northwest winds of 15-20 knots continue on central and eastern Lake Erie this morning while starting to decrease on the western half of the lake. Have cancelled the Small Craft Advisory west of Avon as winds and waves have dropped below criteria. The Small Craft Advisory ends for the nearshore waters off of Cleveland at 4 PM and at 8 PM for the nearshore waters east of Willowick. A brief increase in winds is expected tonight and may have a few hour window where conditions are marginal for needing another Small Craft Advisory between 10 PM and 4 AM. After that, high pressure building east through the Ohio Valley will bring improving conditions for Friday and Saturday. We will be monitoring the remnants of Isaias as it tracks northeast through the Ohio Valley on Sunday. Winds will be on the increase again Monday night ahead of the next front.

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.