Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 180853 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 353 AM EST Sat Nov 18 2017 .SYNOPSIS...
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Low pressure will strengthen as it tracks northeast across the southern Great Lakes through tonight. As the low moves by, a strong cold front will push east through the region. Colder and drier conditions will prevail for Sunday. High pressure will build back into the region Sunday night into Monday. Temperatures will rise to near normal readings for the beginning of the work week before falling to below normal readings for Thanksgiving.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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In a moist/warm air advection regime aloft due to a potent low level jet, showers were occurring across the region early this morning. Low pressure emerging from the southern Plains will strengthen as it tracks northeast to a position near northeast Indiana/northwest Ohio by late in the day. As this occurs, high resolution models suggest that a warm front will develop on another strong nose of a low level jet from mid morning into mid afternoon as the low heads toward northwest Ohio. This should focus and shift showers and embedded thunderstorms to the far northern and northwest sections of our CWFA as the remainder of the region becomes warm sectored. By late in the day, a strong cold front trailing from the low is forecast to push east into the region. With strong low level frontal convergence, a line of showers and embedded thunderstorms is expected. Given a very strong wind regime, and sufficient MLCAPEs of 500 J/kg for this time of the year, there is the concern that some of the storms may bow along the line, allowing for the potential for a few strong to perhaps severe thunderstorm gusts. As a result, SPC has our region in a marginal risk for severe thunderstorms as this line moves east through the region late this afternoon into this evening. Outside the threat for gusty winds within thunderstorms will be the synoptic scale winds. With a tightening pressure gradient and aforementioned strong low level jet, winds this afternoon should easily gust from the south into the lower and mid 30s knots. There is some concern for wind gusts to reach or slightly exceed wind advisory criteria in the WAA regime should the atmosphere adiabatically mix higher than what the majority of models are suggesting. We will have to watch how much saturation occurs this morning and how low ceilings get. A wind advisory is in effect beginning from noon onward, mainly for the synoptic scale gusts approaching 40 knots behind the cold front from late this afternoon into this evening. But given the caveat just mentioned, it is a good thing that it is in effect before frontal passage. Another concern is the potential for locally heavy rain across our far north given some training of showers and storms today along with additional pcpn with the front. Rainfall amounts will likely fall into the 1 to 2 inch range, but will have to watch for any potential flooding issues. Otherwise, it will be warm today despite considerable cloud cover with highs mainly in the lower to mid 60s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
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For tonight, low pressure and the cold front will move east away from the region. There could be a brief period of mesoscale frontogenetic precipitation across the region on the back side of the departing low, otherwise, precipitation should taper off from west to east this evening. Again, winds will be gusty from the northwest with gusts up to 40 knots possible. The wind advisory is in effect until 4 am. Winds should die down some thereafter with gusts in the 20 to 25 knot range by Sunday morning. Under a moist CAA regime, clouds will remain overnight with lows bottoming out in the lower 30s northwest to the upper 30s southeast. For Sunday, in a northwest flow aloft, an embedded s/wv is forecast to dive quickly southeast into the region by afternoon. This feature, along with a cold fetch off of Lake Michigan, may be enough for a few snow showers to occur across our far northern zones. Elsewhere, it will remain mostly cloudy for a good part of the day. Outside of the lake effect, there doesn`t appear to be support for any flurry activity as the cloud layer will not be intersecting the dendritic growth zone, something you need in the winter time for snowflakes to squeeze out of the clouds. Temperatures will not show much of a diurnal rise with highs peaking in the upper 30s to the lower 40s. Locally gusty winds from the northwest can also be expected.
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&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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The ILN CWA will be on the back side of a mid level trough on Sunday night, with any snow showers in the northern half of Ohio likely coming to an end before the long term forecast period begins. Though the pattern will change a little going into the week, one constant will be the wind, as the near-surface pressure gradient will remain strong through Monday and Tuesday -- supporting gusts above 20 knots. High pressure nudging into the area from the southeastern states will force a switch to southwesterly flow on Monday, leading to a warming trend that will continue through Tuesday. As the surface high moves off the mid-Atlantic coast later Tuesday, a weak cold front is expected to move through the Ohio Valley on Tuesday night. This front will be pivoting into a WSW-to-ENE orientation, and will be far removed from its parent low (moving into northern Quebec). With moisture also lacking, a dry forecast will be maintained as this front passes through. This forecast is supported by recent GFS/CMC model runs, though it should be noted that the ECMWF model has been trending toward a deeper shortwave, and thus a solution that allows for some precipitation to occur with the front. Either way, not expecting as strong of cold advection as with the current weekend setup. Nonetheless, max temperatures will drop around 10 degrees from Tuesday to Wednesday, before starting a slow recovery through the rest of the week. Beyond this front, the ILN CWA is likely to remain between weather systems (in what is actually somewhat of an active pattern for other parts of the CONUS) through at least Friday.
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&& .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... First round of precipitation was pushing into the region early this morning on the nose of a fairly potent low level jet. Showers with some embedded thunder can be expected. Ceilings will begin out as VFR but with gradual saturation, they should drop into the MVFR category overnight. LLWS will be an issue due to the strong wind flow off the surface. It will last until 14Z, but there are some indications that it may be need longer than this. Will address this once again with the 12Z TAF issuance. For today, low pressure will deepen as it heads northeast toward the southern Great Lakes. The overall wind field will increase as well which will bring gusty southerly winds. Showers with embedded thunder should show an overall movement toward the north as a warm front lifts through the region. Then, as the low continues on to the northeast, an attendant cold front will swing east through the region late this afternoon and evening. This will bring a focused line of showers and embedded thunderstorms. Gusty winds can be expected with any storms with stronger synoptic scale wind gusts in the 35 to 40 knot range expected behind frontal passage. Ceilings and visbilities will predominately remain MVFR with local IFR possible, especially with the frontal precipitation. Will fine tune this with later TAF updates. For the overnight period, as the low and front continue to move away from our area, precipitation will taper off from west to east. CAA stratocumulus will then envelope the region with MVFR ceilings which will linger into Sunday. Gusty winds will reduce to 25 knots toward Sunday morning. OUTLOOK...MVFR ceilings to linger on Sunday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...Wind Advisory from noon today to 4 AM EST Sunday for OHZ026- 034-035-042>046-051>056-060>065-070>074-077>082-088. KY...Wind Advisory from noon today to 4 AM EST Sunday for KYZ089>100. IN...Wind Advisory from noon today to 4 AM EST Sunday for INZ050- 058-059-066-073>075-080. && $$ SYNOPSIS...Hickman NEAR TERM...Hickman SHORT TERM...Hickman LONG TERM...Hatzos AVIATION...Hickman

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