Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 181744 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 144 PM EDT Wed Apr 18 2018 .SYNOPSIS... A low pressure system will track through the Ohio Valley tonight into Thursday, bringing a chance of precipitation. Precipitation will begin as rain this afternoon and then mix with and change to snow late tonight before ending Thursday. A large area of high pressure will then build into the area for the end of the week into the weekend, providing dry weather conditions. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A small area of high pressure remains in place across the ILN CWA this morning, on the north side of a strengthening warm front. A band of clouds (5kft-7kft) is also in place, developing in some warm ascent aloft (north of the surface front). The biggest source of uncertainty for the forecast today is how far north the warm front makes it into the area, with a high temperature forecast that is rather sensitive to a tight gradient. Current trends and NAM/GFS projections suggest the current forecast could be too generous, but RAP/HRRR runs are pretty much dead-on with what is in the grids. At this point, it seems better to leave the current expectations in place. With sun expected in the southern sections of the CWA, and a very dry air mass in place, there should be room for big gains in temperatures this morning and early afternoon. Previous discussion > A wedge of high pressure kept the area mainly clear into the first part of the night. Temperatures these clear skies allowed temperatures to freezing across the northern half of ILN/s FA. Have continued the freeze warning across portions of the area where the northern portion of the area where the frost freeze program has begun. Favorable isentropic lift has led to the development of clouds across the south, so temperatures have stayed above freezing. Developing surface low to move into the mid MS VLY early today and then into western Ohio by evening. Favorable isentropic lift will continue to lead to cloud development across the area this morning. Model solutions are consistent in holding off rain until later this afternoon. Will ramp pops up to likely across the north where the best moisture/lift will exist. Temperatures will range from the lower 50s north to around 70 south in the warm sector. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Surface low pressure to tack off to the east with sharp upper level trof settling into Ohio overnight. After a temporary lull in pcpn activity this evening expect an increase in showers with a mix with and change over to snow overnight. Any snow accumulation is expected to be minor and on grassy areas. The gradient tightens up in t he wake of the surface low with west to north winds gusting up to 30 mph. Lows tonight to range from the lower/middle 30s north to the upper 30s south. Mid/upper level trof axis to pivot east with a northerly flow over the region. Precipitation will come to an end during the morning hours from west to east. Expect to see a good deal of sun during the afternoon with northwest winds of 15 to 20 mph. Temperatures will be around 15 degrees below normal with highs from the mid 40s north to near 50 south. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Surface high pressure forming under a northwest flow aloft will be building into the Ohio Valley Thursday night. The high will progress very slowly eastward across the region Friday, Saturday and Sunday, reaching the New Jersey Coast on Monday. Dry weather is indicated through the weekend and into next week due to this moisture starved system. The dry period may come to an end Tuesday when a weak cold front is forecast to develop ahead of an upper trough to the northwest, bringing a chance of showers. A warming trend can be expected due to warm advection and insolation. Highs starting out cool in the low to mid 50s will increase to the just above normal mid and upper 60s by Tuesday. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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VFR conditions will continue this afternoon, with generally light southeasterly winds. The situation will change this evening, as a line of showers moves through the region, possibly containing gusty winds and MVFR conditions. After the line moves through, winds will shift to the west and become gusty, possibly as high as 30 knots at the Cincinnati airports. Ceilings will then gradually lower through the overnight hours, with some additional light precipitation moving into the area. This will be handled with a VCSH for KDAY/KILN and some prevailing light snow (MVFR) at KCMH/KLCK. Winds will remain somewhat gusty as they shift to the northwest going into Thursday. Ceilings may briefly drop to IFR during the early to mid morning hours, but a gradual improvement in ceilings is expected by afternoon. OUTLOOK...No significant weather expected.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...Hatzos/AR SHORT TERM...AR LONG TERM...Coniglio AVIATION...Hatzos

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