826 FXUS61 KILN 061946 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 346 PM EDT Mon Sep 6 2021 .SYNOPSIS... High pressure will remain across the Ohio Valley tonight. The high will then move east on Tuesday. A cold front is expected to move through the area late Tuesday into Wednesday, bringing a chance of showers and thunderstorms, and some slightly cooler temperatures for the rest of the week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... GOES 16 satellite imagery this afternoon is depicting some agitated cumuliform clouds in a zone along the I-70 corridor. Mosaic radar in turn is showing some isolated light shower activity developing in this zone. Thus, will carry a slight chance for showers into the evening hours for locations between I-70 and the Ohio River. Otherwise, skies should become mostly clear overnight as high pressure remains across the Ohio River Valley. Winds will become light to calm over the southern zones which will allow for river fog to develop again. Lows will fall into the upper 50s to the lower 60s. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... Models are in fairly good agreement in terms of synoptic and mesoscale features to affect the region during the Tuesday/Wednesday time frame. On Tuesday, high pressure will move east of the area. Meanwhile, low pressure and a cold front will push into the western Great Lakes. An increasing pressure gradient between the departing high and approaching low/front, along with diurnal mixing, will bring breezy conditions to west central Ohio and the Whitewater/Miami Valleys. A steady sustained southerly flow with local gustiness can be expected elsewhere. Our region will be firmly in the warm sector with mostly sunny skies forecast. This will allow temperatures to warm into the lower to mid 80s. For Tuesday night into Wednesday, a large scale mid level trough will dig southeast into the Great Lakes and Ohio Valley. Embedded s/wv energy, combined with moisture and some low level convergence along and ahead front will bring scattered to numerous showers to the region. Instability will be decreasing ahead of the front overnight Tuesday into Wednesday, so only a low chance of thunder is expected. Decent subsidence in the dry slot behind the front will allow skies to clear on Wednesday. After lows in the lower to mid 60s, highs on Wednesday will warm into the upper 70s to near 80. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Surface high pressure works into the Ohio Valley Wednesday night and stays in place through Friday night along with upper level troughing. During this timeframe, light northwesterly winds can be expected during the daytime hours with partly cloudy skies. Calm and clear conditions are likely during the nighttime hours. Forecast highs are in the upper 70s and forecast lows are in the 50s. There is the slight chance for a few sprinkles or a shower on Thursday with a vorticity max moving through the area, but overall dry conditions are expected during the second half of the work week. Surface high pressure moves east of the Ohio Valley on Saturday thereby allowing southwesterly flow to redevelop. Moderating temperates and ridge building results from southerly flow. Highs on Saturday are likely to be in the lower 80s with lows near 60 Saturday night. The next chance for rain may arrive in the Sunday to Monday timeframe with the arrival of a cold front. However, there is still uncertainty as to whether a front will or will not be in the region toward the end of the weekend. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... A weak frontal boundary will settle across northern Indiana and northern Ohio this afternoon. Limited moisture along and ahead of the front will result in at least FEW-SCT cumuliform clouds. There may be enough diurnal instability and weak low level convergence to produce a few sprinkles or isolated showers across the northern terminals. This probability is still too low of a threat to mention in the terminals. Winds will be from the west around 10 knots with gusts between 15 and 20 knots. For tonight, a few sprinkles or isolated showers may linger into the evening, then skies will become mostly clear. Winds will diminish, becoming light southerly. Winds will likely go calm in some of the river valleys, resulting in river valley fog. Have placed at least IFR visibilities at KLUK. On Tuesday, surface high pressure over the Ohio Valley will move east while the weak frontal boundary will move northeast as a pseudo warm front. Another frontal system will make its way southeast across the western Great Lakes and middle Mississippi River Valley. Our region will be firmly in the warm sector ahead of this next system. The surface pressure gradient is forecast to increase which will result in breezy conditions. South winds 10 to 15 knots will gust from near 15 knots along the Ohio River to 25 knots across northern locations during the afternoon hours. OUTLOOK...MVFR conditions will be possible with showers Tuesday night into Wednesday morning. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hickman NEAR TERM...Hickman SHORT TERM...Hickman LONG TERM...Campbell AVIATION...Hickman