Winter Storm Warning in Effect

Real Time Bowling Green Weather Radar:

**Winter Storm Warning in effect from February 20, 3:00 PM CST until February 21, 6:00 AM CST for Allen, Barren, Butler, Edmonson, Logan, Simpson and Warren County **

This Afternoon – PM Snow Showers – High 26° / Tonight – Snow to Wintry Mix – Low 26↑°

3pm 25°– 6pm 26˚ – 9pm 27˚ –12am 29˚ – 3am 31˚– 6am 32˚

Good afternoon, a winter storm warning is in effect for all of south central Kentucky, with a mix of snow, sleet, freezing rain, and rain slated to impact the region this weekend. With the wide variety of precipitation types on the table, all eyes will be on the temperature today. Temps are currently in the low to mid 20s across south central Kentucky, and we’ll only get warmer over the next 24 hours.

Overcast skies have settled over the state ahead of an area of low pressure to our southwest. This low will move northeast this evening, continuing to pump warm, moist air into Kentucky.

Scattered precipitation is expected to move into our area from the southwest around sunset. The atmosphere should be cold enough to support all snow at the onset of precipitation, but expect a fairly quick transition to sleet as we expect to see warmer temperatures aloft.

Regardless, a quick inch of snowfall will be possible this evening before precipitation changes to sleet. The following 4km NAM model loops from 3pm – 9pm tonight.  It illustrates the potential for a quick burst of snowfall quite well.

12Z 4km NAM simulated reflectivity valid from 3pm until 10pm CST tonight (Courtesy: College of Dupage)

Sleet will continue for a few hours before a transition to freezing rain. Freezing rain occurs when the atmosphere is warm enough to melt frozen precipitation, while surface temperatures remain below freezing. This causes the rain to freeze on contact. Check out this predicted temperature profile at midnight for Bowling Green showing freezing rain.

18Z NAM temperature sounding valid at midnight CST tonight (Courtesy: College of Dupage)

Expect freezing rain to continue until around 3-6 AM tonight, with ice accumulations up to 0.25″ possible. This thinking lines up well with the NWS Louisville forecast. Many areas to our north that see less ice will see higher snowfall totals. Should these ice accumulations come to fruition in southern Kentucky, we could be looking at concerns regarding falling tree limbs and power lines. This could obviously lead to power outages.

Screenshot 2015-02-20 14.37.51
Courtesy: NWS Louisville

With the wide variety of precipitation types expected tonight, this is a low to medium confidence forecast. We’ll be monitoring temperatures very closely and “nowcasting,” since a change as small as a few degrees could mean some big changes to the forecast. Remember to use the app titled mPING to help report precipitation types to the National Weather Service.

Saturday – Heavy Rain – High 36° / Sat Night – Wintry Mix Ending – Low 29°

Surface temperatures are expected to rise above freezing by daybreak tomorrow, which means our precipitation type will shift to rain for the majority of the day. Travel will still be a concern, with water drains likely to get clogged from broken sheets of ice from the thaw.

Another thing to pay attention to is the snowpack atop of buildings and houses. The rain will add a lot of weight to the snow, which could add too much stress for structures to handle. We’ll have to keep close tabs on reports of any buildings coming to the ground.

It will be a very cold rain as well as a heavy rain across the region. Total rainfall amounts tomorrow could range anywhere from 1-3″, with a few rumbles of thunder possible during the afternoon. The WPC expects up to 2.5″ of liquid precipitation to fall before 6pm tomorrow.

WPC QPF forecast valid from 6pm today until 6pm CST Saturday (Courtesy: WPC)

This rainfall has the potential to cause moderate flooding problems across the area, thanks to the snowpack in place already. With storm drains clogged, rivers frozen, and a solid coating of snow and ice on the ground, the water will have nowhere to drain.

By Saturday evening, a cold front will work its way across the state from the northwest. Surface winds will turn northwesterly and temperatures will begin to fall as precipitation moves off to the east. If cold air catches up to the back edge of precipitation, it is possible that we could see some additional sleet and snow accumulations up to 0.5″. Rain is expected to switch back to frozen precipitation around midnight.

Precipitation is expected to come to an end before daybreak on Sunday and we can expect mostly cloudy skies overnight with lows dropping into the upper 20s. Watch out for slick spots to develop on roads as some of the rainfall from Saturday afternoon could freeze overnight.

Sunday – Flurries – High 35° / Sun Night – Cloudy – Low 18°

Temperatures will be colder behind this system on Sunday as an upper-level trough will remain centered over the eastern United States. A quick disturbance will move through this trough which could result in a few flurries during the evening. Otherwise, expect highs to barely climb over the freezing mark under mostly cloudy skies.

The cold air will really settle into the region on Sunday night as low temperatures drop into the upper teens with northerly surface winds.

That’s all for this afternoon, be sure to follow @WxOrNotBG and @WarrenCountyWX on Twitter for real-time weather updates throughout the winter storm.