Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 300911 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 511 AM EDT Thu Mar 30 2017 .SYNOPSIS... A few showers or thunderstorms will be possible today in the warm airmass ahead of a strong low pressure system. Showers and thunderstorms will become more numerous tonight, as the low and its associated cold front move through the Ohio Valley. A few of the storms late this afternoon and this evening may be severe. The low will move slowly off to the east on Friday, when linger precipitation is expected. High pressure will offer dry weather and cooler temperatures for this weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Upper level low over the central plains to slide ne into the Mid MS Vly today and across the Great Lakes tonight. Flow backs and moisture increases across the area. This is a complex weather system with several chances for showers and thunderstorms. Looking at expected details, axis of favorable low level convergence associated with 40 kt llj pivots north ahead of advancing surface warm front this morning. This forcing along with marginal elevated instability may lead to a few showers or thunderstorms early, especially across the northwest counties. These initial early morning storms are expected to be below severe limits. Uncertainty exists regarding potential for severe today. One factor is the amount of instability that develops in the warm sector ahead of the pre-frontal trof. Best instability looks to stay to our sw during the day where genesis region for storms is expected. An axis of instability will work into the southwest late in the afternoon, with blyer capes lkly between 1000 and 1300 j/kg. There appears to be a window with the potential for severe weather this afternoon into evening, with a pre-frontal surface trof pushing into the area. Second stronger 50-55 kt low level jet will provide good axis of lift during late aftn/evening hours, which coincides with this instability. Bulk shear in 0-km layer suggests organized storms will be possible and low level shear is favorable but LCL heights are initially high. However model solns suggest the LCLs drop toward evening. Besides the question of the amount of instability, there is a question regarding phasing of parameters (shear/instability) and then how far east the storms get as they weaken with diminishing instability. Also, Flow backs with the increase in moisture resulting in pw/s increasing to around 1.3 inches by late this afternoon into this evening, which is 200 to 225 percent of normal. Although storms will be moving, the potential for localized heavy rain and flooding will also exist. Will mention the severe potential and flood potential in HWO product. The main threats are damaging winds and large hail and local flooding but isolated tornadoes can not be ruled out. Very Warm temperatures to continue today with highs from the mid 60s far north to the upper 70s far south. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Upper level low to pivot into the Ohio Valley tonight into Friday. Ongoing storms, some with potential for severe weather and localized flooding this evening to push east and weaken overnight. Surface cold front to sweep east thru ILN/s fa toward sunrise Friday. Lows tonight to range from the upper 40s nw to the mid 50s southeast. With the upper low pivoting through Ohio Friday, a good chance for showers will continue through the day. Cloud cover, low level caa and pcpn will keep temperature cooler, closer to normal readings. Expect highs on Friday to range from the upper 50s northwest to the lower 60s southeast. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Upper air pattern will feature a broad ridge for much of the period, interrupted by a couple of vigorous low pressure systems. Showers will be exiting east Friday night behind departing low pressure. High pressure building at the surface and aloft will provide dry conditions Saturday and Sunday. Low pressure will return with showers and possibly thunderstorms on Monday, with showers diminishing Tuesday behind the system. Another area of low pressure arriving quickly on a westerly flow aloft will keep the chance of showers in the forecast on Wednesday, with thunderstorms also possible Thursday. Temperatures will start a bit below normal Saturday under cold advection on a northerly flow, with highs reaching the 50s. Readings are then expected to rise above normal Sunday through Wednesday due to insolation and warm advection, with highs generally in the 60s. Highs may then retreat to around 60 next Thursday under clouds and modest cold advection. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... Upper level low over the central plains to slide ne into the Mid MS Vly today and across the Great Lakes tonight into Friday. Flow backs with an increase in mid and high level clouds this morning. In WAA pattern a few rain showers will be possible across the northern TAF sites this morning. Due to limited coverage have only a mention of VCSH at KDAY/KCMH/KLCK around sunrise. Showers and thunderstorm will develop in the warm and moist environment to our west ahead of surface wave tracking into central IL. These storms to push into the western TAF sites toward evening. Have prevailing thunderstorms overspreading all TAF sites associated with a pre-frontal surface trof, with MVFR conditions developing. Brief IFR conditions will be possible in thunderstorms this evening. Eventually expect MVFR CIGS to develop later tonight in showers with embedded thunder with cold front passage early Friday. East winds at 10 to 15 kts will veer to the south and increase to around 15 kts today. Given a tightening pressure gradient some wind gust in the 25 knot to 30 knot range will be possible this afternoon. OUTLOOK...MVFR ceilings and visibilities likely into Friday evening. MVFR to IFR ceilings likely Friday night into Saturday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...AR SHORT TERM...AR LONG TERM...Coniglio AVIATION...AR

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