Area Forecast Discussion
Issued by NWS Wilmington, OH
Issued by NWS Wilmington, OH
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049 FXUS61 KILN 261758 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 158 PM EDT Thu Sep 26 2024 .SYNOPSIS... As the remnants of Helene track north, rain will spread into the area. In addition, it will become breezy on Friday. Low pressure will then linger in the Ohio Valley through the weekend keeping conditions unsettled. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Morning update... No major changes to the near term forecast with widespread cloud cover enveloping the region. Rain moving into the area remains very light. Adjustments for winds and potential wind headlines for remnants of Helene will be made in the coming hours as the full 12Z model guidance becomes available. Previous discussion... Upper low over the lower Ohio Valley will drop south into the mid South today. A disturbance rotating around the low will move westward across the southern part of the forecast area this afternoon. Remnant surface trough will become reoriented more east-west across southern Ohio into Kentucky. This will result in showers developing and moving west over mainly the southern counties late this morning through this afternoon. Highs will be in the 70s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Wind Advisory update... In collaboration with surrounding offices, a wind advisory has been issued from 10 am to midnight, for winds of 25 to 35 mph and gusts between 45 and 55 mph. The 12Z suite of guidance increased in wind values, as the remnants of Helene are expected to approach the Ohio Valley Friday morning. The pressure gradient will drive strong northeasterly to easterly winds beginning in the morning, intensifying into the early and late afternoon. As Helene continues to gradually strengthen in the eastern Gulf, there is still some uncertainty as to the overall low pressure value as it enters the Ohio Valley. There is certainly the potential for lower and higher wind values depending on the magnitude of the low pressure and the exact track. However, enough confidence was in place to start with a wind advisory focused over a large portion of southwest Ohio, southeast Indiana, and northern Kentucky. The advisory could be expanded or potentially upgraded to a High Wind Warning if necessary. Previous discussion... The remnants of Helene will lift north and then curl northwest, passing south of the forecast area, as it gets absorbed into the preexisting upper low which will be shifting into the Tennessee Valley. Showers will be increasing in coverage, especially the latter part of the night. The showers will pivot in a broad band on Friday afternoon. Rainfall amounts will be 1 to 2 inches across southern counties with less amounts further north, In addition, winds will be increasing as the pressure gradient tightens with the approach of the remnants. There will be a very strong low level jet, but with a very moist environment, expect mixing to not be very deep. However, it will not have to in order to get some rather gusty winds. At this point, have kept winds below advisory criteria, but there is certainly room for those gusts to be higher. There will be rather narrow diurnal range with lows in the 60s and highs in the 70s. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... For Friday night, the remains of Helene continue to push west of the area as it gets wrapped up into the mid level low in the lower Ohio Valley. Helene`s continued weakening and westward progression will bring a sharp rainfall cutoff from east to west across the mid Ohio Valley, but some uncertainty in how quickly the lingering bands will remain. Greatest confidence in higher precip chances is near the Ohio/Indiana border and KY regions due south of Cincinnati. Winds will also decrease Friday night as Helene continues to weaken and push west. Once remains of Helene get wrapped into the mid level closed low, it remains just to the southwest of the forecast area through Saturday morning before slowly becoming more broad and on a slow weakening trend as it slowly pushes east and becomes centered roughly just south of the Ohio River through the remainder of the weekend. Some spread in the solutions for timing of the eastward progression of the mid level low, but overall will bring periods of rain through the weekend with a chance for thunderstorms on Sunday as the closed low begins to open up with an approaching cold front to push toward the region later on Sunday and into Monday. The front begins to push through the region late Monday into Tuesday, bringing a more focused chance for showers and storms. A return to mid level ridging and high pressure with rising temperatures for Wednesday. With plenty of cloud cover and moisture in the region, temperatures will be in the mid 70s into early next week, with lows in the upper 50s to lower 60s. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Still dealing with lingering MVFR CIGs at some of the sites early this afternoon. Improvement to VFR is expected through the afternoon before MVFR CIGs settle in for the remainder of the TAF after 00Z. The TAF period now includes the onset of stronger winds & wind gusts Friday afternoon. These values will likely need some adjustment with future forecasts. LLWS has also been added in for CVG/LUK. ILN may be needed with higher confidence. Plentiful tropical moisture will provide low-end MVFR CIGs, with MVFR VIS expected in moderate rain. IFR restrictions can`t be ruled out. OUTLOOK....MVFR ceilings likely Friday night and possible again Saturday through Monday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...Wind Advisory from 10 AM Friday to midnight EDT Friday night for OHZ042-051>054-060>063-070>072-077>081. KY...Wind Advisory from 10 AM Friday to midnight EDT Friday night for KYZ089>100. IN...Wind Advisory from 10 AM Friday to midnight EDT Friday night for INZ050-058-059-066-073>075-080. && $$ SYNOPSIS... NEAR TERM...McGinnis SHORT TERM...McGinnis LONG TERM...JDR AVIATION...McGinnis