Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 261851 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 251 PM EDT Sun Mar 26 2017 .SYNOPSIS... Showers and thunderstorms will develop today into tonight as low pressure moves to Lake Michigan. After a brief visit by high pressure and drier air early Monday, another low will bring more showers and thunderstorms Monday night and Tuesday. Dry weather can be expected Wednesday under high pressure. && .NEAR TERM /THROUGH TONIGHT/... Upper level low pressure is currently in central Illinois with the second band of precipitation getting ready to exit the CWA. A third band of precipitation has now formed across the IND forecast area and is expected to push east through central Ohio later this afternoon into early evening. The latest run of the GFS is showing slightly higher MU CAPE values for this afternoon (some values slightly above 1000 J/kg). For the most part forecast soundings show this CAPE to be weak and skinny. Shortwave cooling and 800 - 500mb winds of 35 to 40kts will make damaging winds and severe hail the primary severe threats for this afternoon. Due to the above SPC has the area in a marginal risk. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... Monday an area of upper level low pressure will push east across the central United States. This second system will be right on the heals of the Sunday upper level low and will bring a quick return for the chance of showers and thunderstorms. After the brief break Monday morning the upper level low will move towards Illinois with pockets of PVA crossing the ILN forecast area. PWATs will also be on the rise towards 1.10" (NAM and GFS). The best upper level lift from the RRQ will be further south towards Kentucky but with a weak upper level jet streak moving overhead think upper level support will be more than sufficient. MU CAPE values on the NAM across the southern zones are nearing 1500 J/kg while are only around 500 J/kg on the GFS. On the GFS the greatest 0-3km bulk shear is also further south across KY. The NAM on the other hand is more north with the greatest shear and instability. Thanks to the mentioned above SPC has most of the area in a marginal risk. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Weakening upper level shortwave and associated surface low to track through the Ohio Valley Monday night. This feature will provide widespread showers and thunderstorms. As this progressive system shifts east pcpn will come to an end Tuesday. Temperatures will remain above normal, with Tuesday`s highs ranging from near 60 northwest to the upper 60s southeast. Surface high pressure to build across the Great Lakes at mid week. This will provide dry weather Wednesday into Thursday. Temperatures will be closer to normal, with highs on Wednesday ranging from the mid 50s northwest to the mid 60s southeast. Model solutions diverge on handling late week weather system. GFS continues to be outlier and takes the southern plains upper low into the Ohio Valley and therefore is quicker with return pcpn. The more consistent ECMWF and Canadian solutions have the closed low lifting northeast into the upper MS VLY Friday. Will continue to trend the forecast toward the ECMWF/Canadian. Will bring chance pops into the west Thursday and increase these pops to likely Thursday night into Friday, as moisture and instability increase across the region. Will mention chance pops for thunder Friday afternoon into Friday evening. Temperatures to continue a little above normal with highs from the mid/upper 50s north to lower/mid 60s south for Thursday and Friday. As this system exits the region pcpn will end Saturday. High pressure to offer dry weather through the remainder of next weekend. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... Low pressure system is currently rotating over central Illinois and slowly pushing northeast. Second band of precipitation is currently moving through ILN/ DAY with restrictions down to IFR visibilities/ MVFR ceilings possible. As this second round of precipitation passes the TAF sites ceilings and visibilities will recover to VFR. A third band of showers has formed in central Indiana this afternoon and is forecasted to push east through the TAF sites later this afternoon into evening hours. As this band pushes east forecast soundings continue to show the area destabilizing. As this occurs the amount of lightning strikes will also increase. Due to this have added a tempo group for thunder into all the TAF sites. Went ahead and used current radar trends to help with timing of tempo groups. As the line passes through the TAF sites some gusty winds and restrictions in visbilities and ceilings will be possible. As the line passes the TAF sites a brief recovery to VFR will occur with a return of MVFR ceilings possible Monday morning. The NAM is the most aggressive with the return of the MVFR Monday morning while the GFS is more optimistic. The SREF probabilities are more in between the two and have decided to trend TAFs this direction. During the day Monday any MVFR ceilings will quickly recover to VFR with another upper level low moving east across the central United States. By middle of Monday afternoon PVA and upper level divergence will be overhead meaning a return of showers and thunderstorms. For now have left mention out of TAFs as this remains near the end of the period, but future TAF packages will likely have to incorporate this. OUTLOOK...MVFR ceilings and visibilities will be possible late Monday into Tuesday morning. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Haines NEAR TERM...Haines SHORT TERM...Haines LONG TERM...AR AVIATION...Haines

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