Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 120305 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 1005 PM EST Mon Dec 11 2017 .SYNOPSIS... An area of low pressure and associated cold front will move across the region tonight. An upper level disturbance will affect the area on Tuesday. Another low pressure system will pass across the region Wednesday night. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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A cold front has now pushed into the region. Behind it a surge of arctic air will rush into the region. Lake effect snow showers will form over Lake Michigan and will gradually work se towards the region, reaching the region after 3 or 4 AM. Trickier part of the forecast is across the south. There are some indications that some drizzle may try to form, before the snow showers work in. With temperatures dropping through the freezing mark there will be a chance of freezing drizzle, although confidence is not high. Winds will increase behind the low with gusts in the 25 to 35 mph range expected late. Temperatures will fall into the lower 20s northwest to the lower 30s southeast.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... The main threat on Tuesday will be the potential for the aforementioned lake effect snow band or "streamer" to affect parts of our area. The high resolution models have been consistent on bringing this band into our region. All the parameters are there for the possibility of bursts of heavy snow, windy conditions, and temperatures slowly dropping through the 20s. Snow squall potential could result in hazardous driving conditions as motorists may encounter clear conditions followed by near whiteout conditions. As a result, the SPS will continue into Tuesday for the parts of the northern areas, including northern metro Cincy, Dayton metro, Columbus metro (Columbus and points south and west), and west central Ohio. The "streamer" band is expected to pivot northeast through the day as the low level flow backs, so that will keep accumulations from getting out of hand in any one location. Most locations in the band will receive 1 to 2 inches, but west central Ohio may see local amounts around 3 inches. Outside of the band, some scattered snow showers or flurries are forecast, but amounts will be a half inch or less. Again, it will be windy with sustained northwest winds 15 to 25 mph with gusts, especially in the convective band, between 30 and 40 mph. Temperatures will drop into the upper teens northwest and the lower 20s southeast by evening. For Tuesday night, large mid level trough will move east. As this occurs, winds will decrease at the surface and aloft as well as back some from Lake Michigan. This process will allow the band to weaken and break away to the northwest from our region overnight. In fact, a surface ridge will build into our region by Wednesday morning. Skies will clear in the south and become partly cloudy in the north. Lows will generally drop into the 10 to 15 degree range. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Any lake effect snows will be ending early Wednesday with gradual improvement in the morning. Later in the day, a surface low will track towards the region and chances for snow will increase later in the day along the I-70 corridor between Dayton and Columbus, spreading southward towards the Ohio River in the evening, and then lifting northeastward overnight as the surface low crosses the region. Given the cloud cover and northwest flow on Wednesday, this should be the coolest day of the period with readings remaining in the 20s to lower 30s. Continued northwest flow on Thursday will see readings range from the upper 20s in the north to the upper 30s in Kentucky. Temperatures will remain in the 30s on Friday and warm into the 40s on Saturday as a warm front develops and lifts north of the area. Warmer temperatures are expected through the weekend. A surface low will track into the region Sunday or Sunday night. This is a divergent point in the extended models with timing and strength differences, as well as the upper level trough that will be driving its evolution. As of this moment, it appears that the European is an outlier. Have an increased chance for rain on Sunday, possibly starting as a mix of rain and snow and likely changing to snow on the back side Sunday overnight. The airmass behind the low pressure system on the weekend is coming from the west and not expected to be as cold as if the region were in strong northwest flow. Surface flow remains west to southwest as a brief ridge pushes into the area early Monday and return flow sets up behind it. Kept with the model blend given the increased potential for large discrepancies beyond day 5, and a pretty good consensus in the forecast through this time. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... TAFs begin the forecast period in the warm sector. High and mid clouds are working across the region attm. A cdfnt over Indiana will swing across the region between 03-06Z. Behind the front, the region will experience strong CAA. The CAA flow will be nw off Lake Michigan. With -10C and colder air working off the Lakes, snow showers are expected to develop, reaching the western tafs around 09Z. Models are showing a long lake effect snow band coming down into the wrn tafs by 12Z Tuesday. Have VCSH for scattered snow showers at all locations, expect for DAY/ILN. It looks like they have the best chance to be hit by the lake effect band. Kept the 3SM -SHSN from previous forecast, but vsbys will be lower depending exactly were the strongest part of the band sets up. Winds on Tuesday will continue to increase due to tightening sfc pressure gradient. Expect them to be from the west and northwest, sustained between 15 and 20 knots with gusts in the lower 30 knots. Beginning around 18-19Z the band will begin to drift to the ne. This means that CVG/LUK, should see conditions rise to VFR. Other tafs will see a chance of snow showers through the end of the period, although the band should be weakening as the low levels back with time away from Lake Michigan. OUTLOOK...MVFR ceilings and visibilities possible Wednesday night. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hickman/Sites NEAR TERM...Sites SHORT TERM...Hickman LONG TERM...Franks AVIATION...Sites is the U.S. government's official web portal to all federal, state and local government web resources and services.