Area Forecast Discussion
Issued by NWS Wilmington, OH
Issued by NWS Wilmington, OH
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825 FXUS61 KILN 260210 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 1010 PM EDT Wed Sep 25 2024 .SYNOPSIS... Tropical remnants will bring rain and wind to close the work week. Low pressure lingers around the Ohio Valley through the weekend with continued rain chances. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... Stalled frontal boundary near/SE of I-71 corridor will meander slightly overnight but hardly change its position. A lack of drier air with the front will keep a milder air mass in place overnight, along with higher dewpoint values. Near and just SE of the front, a brief, isolated shower remains possible. A rumble of thunder cannot be ruled out with any shower given the little bit of elevated instability available, but this won`t be a high chance by any means. Low level moisture will become trapped under a blanket of cloud coverage, especially near/SE of I-71. This could lead to some patchy fog development as well, especially along the river valleys where dewpoints could be a degree or two higher. Regardless, dewpoint depression of only 1 or 2 degree expected for this region. Expect overnight lows to remain in the 60s for most. && .SHORT TERM /7 AM THIS MORNING THROUGH 6 PM FRIDAY/... The stalled front washes out during the day on Thursday as the strengthening surface low pressure to the south deepens in response to Hurricane Helene moving into the Gulf Coast. Not much changes during the day with regards to the overall weather because the rainfall chances are still focused to the south. The only substantial change will be that the weak and variable winds will become more northeasterly during the afternoon. Low level southeasterly flow increases Thursday evening with more significant tropical moisture advection moving north into the Ohio Valley. This will be the first chance for periods of light to moderate rain, primarily along the Ohio River and south. Better chances for rain will be more plausible during the long term period. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Friday is shaping up to be a wet and breezy/windy day as the remnants of Helene move north then northwest across the Tennessee Valley. The surface pressure gradient will increase as the low moves northwest. This, along with strong winds aloft, should bring wind gusts in the 25 to 35 mph range. There could even be some isolated 40 mph gusts, especially along and south of the Ohio River. Saturated low levels should prevent winds from getting stronger (limited mixing). Widespread showers, isolated thunderstorms, are expected south with decreasing chances of pcpn as one heads north. Despite the tropical moisture, the speed of the pcpn shield should limit rainfall amounts which will actually be beneficial to our drought stricken region. By Friday night, the mid level energy that once was Helene will be merging into a synoptic mid level closed low to our southwest. This process will result in a decrease in pcpn chances overnight. Winds will also diminish as the surface low undergoes frictional decay. Rainfall amounts will range from 0.25 to 0.50 inches north to 1.50-1.75 inches along and south of the Ohio River. For the upcoming weekend, more opportunities for rainfall will be possible as the center of the mid level closed low slowly rotates east/northeast across Kentucky and Tennessee, weakening and shearing as it goes along. Will continue with clouds and chances of showers, with some isolated thunder possible during the peak diurnal cycle. The mid level closed low is forecast to weaken, shear, and open up as upstream energy digs east/southeast into the Great Lakes Monday into Wednesday. This process will also be associated with a cold front, expected to pass through during the Tuesday/Wednesday time frame. Lingering pcpn chances should end after frontal passage. As for temperatures, they will be held down on Friday with clouds, rain, and wind. The weekend will feature highs 75 to 80 and lows in the 60s. A cooling trend is then expected by Wednesday behind the cold front, along with a much drier airmass. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Stalled boundary along with ample low level moisture will lead to a number categorical reductions tonight. Largest impact expected to be from lower CIGs as majority of terminals are now expected to observe IFR CIGs. KDAY has the best chance to remain VFR overnight but will eventually observe some MVFR CIGs after sunrise Thursday as lower CIGs push northward. Given the shallow low level moisture, some BR expected to develop overnight as well, but expecting mainly MVFR vsbys with pockets of IFR (mainly for KLUK, perhaps KILN as well). Minor improvement in CIGs expected after sunrise on Thursday, but improvements will be gradual for CIGs. Still anticipating MVFR CIGs to persist through the afternoon. Vsbys should be more quick to return to VFR with the help of surface winds increasing out of the east-northeast around 5-10 kts. OUTLOOK...Due to the remnants of Tropical Cyclone Helene, wind gusts between 30 and 35 knots and LLWS are possible Friday. MVFR/IFR reductions also possible Friday night through Sunday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...McGinnis NEAR TERM...Clark SHORT TERM...McGinnis LONG TERM...Hickman AVIATION...Clark