Area Forecast Discussion
Issued by NWS Wilmington, OH

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065 FXUS61 KILN 230039 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 739 PM EST Wed Feb 22 2017 .SYNOPSIS... A mild airmass will be over the region tonight. Showers will be possible late tonight and Thursday when a warm front is forecast to develop across northern Ohio. A strong cold front will push through late Friday, bringing widespread showers and thunderstorms. && .NEAR TERM /THROUGH THURSDAY MORNING/...
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Southerly flow will keep a good amount of low level moisture in the region this evening and overnight ahead of an approaching cold front. Some breaks may be found along and south of the Ohio River this evening, but a general cloudy sky cover is expected overnight and into Thursday. Temperatures will see about a 5 degree or so drop from current readings in the upper 50s and low 60s into the mid and upper 50s tonight. Low clouds are expected to expand back southward overnight as temperatures cool towards the dewpoints. With the abundant low level moisture, fog is expected to develop again tonight. A cdfnt will approach from the nw overnight and provide some lift and an increased chance of scattered light showers.
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&& .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... The cdfnt will reach the nw counties Thursday morning, before stalling. Scattered showers will be possible on Thursday with the low level convergence in the area, but there will be a transition of better PoPs towards the northern counties by late afternoon. Morning clouds are expected to break during the afternoon allowing temperatures to jump into the mid to upper 60s. A 70 is possible in nrn KY. Records are possible at Columbus and Dayton. The stalled front will begin to transition northward as a warm front Thursday Night. A low chance of showers will remain across the north, but the front will be drifting north taking the better convergence with it, so left the mention of thunder out. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Main focus in the immediate long term will be the potential for severe storms Friday evening into early Saturday morning. Upper level low will pivot northeast from the central Plains to the western Great Lakes and western Ohio Valley Friday into Friday night. As this occurs, heights will fall with the upper level low while surface low pressure deepens as it travels northeast from Iowa to northern lower Michigan. We will be in the warm sector ahead of this system for most of daylight hours on Friday. This will allow for unseasonably warm temperatures and breezy conditions, along with a weak capping inversion. Highs in the lower to mid 70s will threaten or break records at the big three climate stations of KDAY, KCVG, and KCMH. Then, the focus will shift to our west late in the day and during the evening as strong upper level dynamic lift combines with low level convergence with either the cold front front or a prefrontal trof/low level convergent region to produce showers and thunderstorms. Bulk shear, whether 0-3 km or 0-6 km, will be sufficient for organized storms. The question almost always lies with how much instability will be realized. At this time, MLCAPES could approach or exceed 1000 J/KG MLCAPE across our western zones during the evening, which will be plenty within a strong wind regime. As such, SPC SWODY3 has our region in an enhanced/slight risk for severe storms Friday night. Main threat will be damaging winds, especially if a quasi-liner mesoscale feature(s) form (QLCS?) to produce bowing segments. Will also have to add the threat for large hail as mid level lapse rates approach 8.0 to 8.5 C/km (steep), wet bulb zeros remain in the favorable 7-8 kft range, and if some storms rotate, it will add extra vertical motion due to a vertical pressure gradient differential. Finally, can not rule out an isolated tornado, especially if a renegade supercell should form ahead of the main convective line, or with some embedded misocyclones possible within the mesoscale convective line. Convection is expected to clear our eastern zones between 06Z and 12Z Saturday. In the wake of the cold front, low will drop to the upper 30s west to the lower 50s east. For Saturday into Saturday night, upper level low will rotate across the Great Lakes. As pcpn ends across the east, CAA along with some upper level lift will bring some instability showers to the area, with the best chance expected across our northwest zones during the afternoon/early evening. Showers will mix with snow later in the day and evening as colder air continues to filter into our area. The threat for pcpn will end Saturday night as the upper level low moves east and surface ridging builds in from the west. It will be windy on Saturday as a decent pressure gradient teams up with CAA/momentum transfer to bring wind gusts in the 30 mph to 40 mph range. Temperatures will exhibit a slow fall during the day. Lows will bottom out in the mid to upper 20s by Sunday morning. Long range operational models are in fairly good agreement for the remainder of the extended, with some timing and strength issues to hash out. Sunday will see a reprieve in terms of a pcpn threat with high pressure moving east. Highs in the lower to mid 40s will be seasonal for late February. The next weather system is then poised to affect the region Sunday night into Monday night. Rain, or a chance of rain/snow north will occur Sunday night into Monday with just rain expected all locations by Monday night. A stronger system is then expected during the Tuesday/Wednesday time frame. Warmer, moist air will eventually bring the likelihood of showers with embedded thunderstorms. Highs will push to above normal readings in the 50s and 60s. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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Some MVFR cigs will be found over the southern TAF sites at KCVG and KLUK before they drop down into the IFR category overnight. As the cold front approaches overnight, lift and convergence will bring an increased threat for widely scattered showers covering the same flight category as the ever-present low cloud deck persists, especially over the northern TAF sites. A brief period of LIFR cigs may occur in the morning as the cold front washes out over the I-71 corridor and stagnates. Afternoon will see some improvement as the cloud deck lifts once again. Central Ohio may see a continued threat for light rain and associated lower cigs/vsbys through the end of the valid forecast period. OUTLOOK...Thunderstorms are possible Friday and Friday night. MVFR ceilings and vsbys are possible Saturday and Monday.
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&& .CLIMATE... Record High Temperatures Date CVG CMH DAY Wed 2/22 71(1922) 70(1930) 69(1922) Thu 2/23 72(1985/1996) 66(1906/1985) 68(1985) Fri 2/24 72(1930) 72(1961) 67(1930/1961) && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Coniglio/Sites NEAR TERM...Franks/Sites SHORT TERM...Sites LONG TERM...Hickman AVIATION...Franks CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.