Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 080602 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 102 AM EST Thu Dec 8 2016 .SYNOPSIS... As an upper level low pressure system moves eastward across southern Canada, arctic air will invade the region over the next few days. As the cold air flows over the Great Lakes, flurries and snow showers will be possible on Friday, but a more significant chance of rain and snow will move into the region for the later half of the weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... An upper level disturbance will begin to work into the area overnight. Although there are some returns showing up on the radar the low levels are very dry. Due to this continued a dry forecast for the overnight hours. Cannot rule out some isolated flurries. Colder air will work into the region overnight. Temperatures currently in the 30s are expected to drop into the 20s as the colder air moves in. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... On Thursday the H5 low will be in ern Canada, with a sfc trof/arctic front working down through the lakes. As the sunrises, there should still be some mid and high clouds, but they should pull e by mid day. During the afternoon, the better H8 CAA will begin to work south of the Great Lakes and a deck of sc will gradually overrun the area. Temperatures will struggle to warm with the increasing cloud cover and caa. Highs will range from the mid 20s in West Central Ohio to the lower and mid 30s in the se counties. As Thursday night progresses, H8 temperatures will drop to -12C and the flow will align off Lake Michigan to bring flurries to the region. Some snow showers will be possible in West Central Ohio closer where the better fetch off of Lake Michigan may set up. The pattern will linger into the first part of Friday, but then the flow begin to back off of Lake Michigan and it should bring a gradual end to the lake effect snow activity. At this time, I am not thinking snow accumulations will be more than a dusting if any. The clouds and pcpn should help the temperatures from dropping too low. Kept lows Thursday night around 20 degrees. Highs on Friday will work only into the upper 20s to lower 30s. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... High pressure centered over the Tennessee Valley on Saturday will provide a dry forecast over the CWA, with enough breaks in the clouds for some sunshine during the midday and afternoon. Despite some sunshine, it will remain cold with high temperatures likely remaining below freezing through much of the CWA except perhaps south of the Ohio River into northern Kentucky where high temperatures may hit/slightly exceed the freezing mark. High pressure shifts to the east into the middle Atlantic states Saturday night. Result will be a south/southeast flow in the low levels and some warm advection which will allow for clouds to roll back in Saturday evening and for precipitation to develop well ahead of low pressure over the central Plains. This low is forecast to move northeast into/through the Great Lakes, eventually allowing a cold front to pass through Sunday night or Monday morning. Until then, confidence has increased in a period of precipitation Saturday night into Sunday and therefore have likely pops across the CWA. Precipitation type will likely be snow at the onset, but with some warmer air moving in from the south on Sunday, expect snow to mix with/change to rain particularly south of Interstate 70. GFS is colder than the ECMWF, and therefore used a blended approach for p-type transition Sunday. Eventually, any lingering precipitation would change back to snow Sunday night/Monday morning as colder air moves back in behind the cold front. High pressure briefly builds in for Tuesday, but a fast-moving, weak system may bring a chance of light precipitation by Wednesday, although timing this far out is in question. Below normal temperatures are expected for the long term forecast period. && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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The center of a large scale upper level trough was located south of James Bay Canada this morning. This feature will rotate east/northeast through the day. For this morning, considerable mid clouds will exit the region around 12Z. Thereafter, CAA in conjunction with stratocumulus clouds will advect/develop through the day as they move southeast. It appears that the northern terminals will see some MVFR ceilings by 18Z while the southern terminals remain VFR. An increasing pressure gradient along with some diurnal mixing will bring wind gusts into the 20-25 knot range. For tonight, low level flow will shift to a northwest direction, allowing cold air to move across the Great Lakes. This will allow stratocumulus to thicken and lower overnight. There could be some scattered flurries, with a few snow showers possible near the northern terminals. Ceilings will all drop into the MVFR category, with some models suggesting ceilings dropping below 2000 feet in some spots. Winds will remain a little gusty overnight, but perhaps not as high as today with some night time cooling/decoupling. OUTLOOK...MVFR ceilings expected on Friday, which may linger into Friday night. MVFR/IFR ceilings and visibilities possible Sunday into Monday.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos/Sites NEAR TERM...Novak SHORT TERM...Sites LONG TERM...BPP AVIATION...Hickman

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