Blustery Mon & Tues; Pleasant Wednesday
Good afternoon folks! The timeline for rain and snow have shifted slightly, with showers expected to develop across the area as soon as the evening hours (Sunday), filling in regionwide by the pre dawn hours and exiting sometime mid - late Monday morning (this is roughly 2 - 4 hours slower than our previous timeline). This has also reduced our chance for high elevation snow with a trace - dusting the best we can hope for above 5000', whereas previously we forecasted a dusting up to an inch. Sunny skies take over by the late morning - early afternoon hours Monday but breezy and cold conditions take over and linger through the day on Tuesday, with winds relaxing Tuesday night, setting the stage for a temperature inversion. Cold air advection on Tuesday gives way to a developing upper level ridge and we'll see a shift from westerly winds to southwesterly on Wednesday, allowing temps to warm roughly 10 - 12 degrees over Tuesday. Fair weather spills over into Thanksgiving Day but clouds are likely to thicken after midday, with temps reaching the same levels as Wednesday. A fast moving disturbance will clip the region Friday, with most of the action occurring further north in the Ohio Valley, however scattered light showers are likely during the day with a few high elevation ridgelines and peaks above 5000' experiencing light snow that may result in a dusting. Sunshine takes over Saturday and after a chilly Friday we'll return to near normal levels for the holiday weekend.
We'll kick off the timeline Monday morning after a quarter of an inch of rain falls across the region Sunday night, with slightly higher totals between 0.50 - 0.75" along the TN line. Shower coverage will be waning as we move past sunrise and most of the activity will come to an end by the mid - late morning hours, with a handful of light showers lingering along the TN line into the early afternoon hours. Light snow and wind whipped flurries will fall for a few hours late Monday morning but coverage will be so sparse along the TN line and moisture declining that accumulation chances are slim at best. Temps will be chilly for late November as they reach the upper 40's - low 50's in the valleys, however cold air advection later in the day will force temps downward above 4500' as soon as the early afternoon hours; upper 30's above 5000' for the high. Northwesterly winds around 10 - 30mph will pick up after midday and remain steady into Tuesday afternoon, peaking during the late evening hours Monday with gust up to 40mph along the highest ridgelines. Overnight lows bottom out to the upper teens - mid 20's across the region under clear skies.
Tuesday offers up a chilly day with highs in the mid 30's - upper 40's depending upon elevation, which is roughly 10 degrees below normal for late November. Even though sunny skies sit overhead all day, westerly winds around 10 - 25mph will make for a blustery day, however winds should decouple and calm down as we approach sunset, with clear skies and little to no wind setting the stage for the radiational cooling Tuesday night. This will lead to temps in the valleys plummeting to the upper teens - low 20's, while the ridgelines hold to the upper 20's; valley fog is a possibility.
Wednesday features more fair weather but temps bounce back to the mid 40's - upper 50's depending upon elevation under mostly sunny skies. Overnight temps settle into the upper 20's - mid 30's as clouds develop overnight.
Some sun and clouds start the day on Thanksgiving Day, but eventually mostly cloudy skies take over ahead of the next rainmaker scheduled to arrive Friday. Temps will reach the mid 40's - upper 50's once again Thursday, with temps on Friday cooling down to the low 40's - mid 50's as scattered light showers pepper the region; tenth - quarter inch of rain regionwide. Sunshine returns Saturday and temps could push into the low 60's for the first time this week.
We'll stop here and circle back Tuesday late morning with a new discussion and a better handle on the Friday rain/snow event. ENJOY!