textproduct: Wilmington

WHAT HAS CHANGED

Winter weather advisory was expired at noon.

KEY MESSAGES

1) Several opportunities for light snow are expected tonight through Friday night. Chances of greater than one inch of total snowfall accumulation are highest (40-50%) across portions of central, southwest, and southern Ohio.

2) Bitterly cold temperatures are forecast Sunday through Wednesday morning with the coldest temperatures occurring Tuesday morning.

DISCUSSION

KEY MESSAGE 1... A large lumbering trough over the Midwest and Great Lakes will provide several opportunities for precipitation across the Ohio valley over the next 48 hours. While significant accumulations are not currently expected, the exact timing and duration of the snowfall could lead to impacts across the area. Overall, each scenario is low in confidence, which will likely result in short term changes to the forecast as confidence increases.

Tonight: The first round of precipitation arrives later tonight ahead of the next cold front. Isentropic lift occurring within a strengthening warm air advection region supports upward motion. Given the cooler air mass in place today, the broad temperature conditions will still support snow, even though temperatures above the surface will be increasing. Batches of light snow will move through eastern Indiana and western Ohio between early Friday morning (5am) and late morning (11am). Low level dry air will help to limit saturation of the snowfall to the surface, but forecast soundings indicate the potential for lift within the DGZ, supporting larger snowflake size. Current expectations for snowfall accumulations are for a few tenths of an inch to fall with the highest confidence currently placed across eastern Indiana and western Ohio. With the antecedent cold conditions, some challenging travel could develop where this snow accumulates.

Friday evening and Friday night: The cold front arrives later in the evening, with the potential for scattered snow showers along and behind the front. Light accumulations with these snow showers could lead to challenging travel wherever the snow showers occur. These showers will be possible area wide.

Ahead of the front, there are some indications that more favorable jet energy may develop across southern Ohio and northern Kentucky, providing an opportunity for more sustained precipitation. Due to warmer surface temperatures Friday afternoon, rain-snow mix may prevail before either dynamic cooling cools the column in the heavier rates or colder air advects in from the west, supporting all snow. Once again, given the precipitation type complexities and the lower confidence on the placement of the band, confidence on impacts to this area is low.

Saturday: Finally, another wave of energy arrives within the large trough late Friday night into the day on Saturday. Periods of light snow along with scattered snow showers would provide the opportunity for additional light accumulations area wide.

KEY MESSAGE 2...

The large lumbering trough remains in place over the region throughout the weekend, but a reinforcing shortwave will supply a period of much below normal temperatures spanning from Saturday evening through Wednesday morning.

Locations across northern portions of the area will see the coldest conditions due to the stronger winds, but the whole area should expect multiple days of single digit feels-like temperatures. Cold weather headlines are most likely for Monday night into Tuesday morning with values between -10 and -15 across the north and 0 to -10 across the south. At that time frame, normal temperatures are in the single digits with values near 0 from Dayton to Columbus and northward. This period of cold temperatures remains highlighted in the HWO.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Remnant light snow will exit CMH/LCK over the first hour of the period with VFR moving as well. Lake effect clouds are moving eastward into western Ohio the rest of the afternoon and into the evening hours so despite the ongoing clearing, a mention of low- level clouds remains over the next few hours.

Westerly winds will lessen later this evening, turning more southwesterly ahead of the next system approaching tonight. Chances for precipitation are possible for the last 10 hours (08Z-18Z) of the TAF but confidence remains low on the exact timing and any potential restrictions at each site. Kept the same theme going from the last issuance with PROB30s used to mention the lower confidence threat.

Of higher confidence, increasing southerly-southwesterly wind gusts will begin after 14Z with values ranging between 20 to 30 knots.

ILN WATCHES/WARNINGS/ADVISORIES

OH...None. KY...None. IN...None.