Forecast Discussion 18:41:35.2708

…Updated Aviation Discussion…

.Forecast Update…
Issued at 550 PM EST Wed Nov 16 2022

Monitoring area WSR-88D returns, observations and traffic cameras from both Indiana and Kentucky decided to up our PoPs to around 20 percent for some scattered light snow and flurries through this evening. Impacts remain minimal but a brief burst of snow in an isolated band, especially across southern IN and norther KY along the Ohio River is possible. SPC Meso-analysis shows a 25kt 850mb LLJ over northern KY and southern IN this evening with the RAP
suggesting we could see areas up to 30kts adding to slight enhance lift. Model soundings and cloud tops support areas of saturation in the DGZ along with some steep low-level lapse rates where we had sunshine close to 6 C/km. While there is support for light snow we have dry a dry layer below 3K ft keep most of the snow showers light to just flurries. Temperatures will also remain slightly above to just near freezing during the time of highest PoPs and ground temperatures as well as road temperatures remain above freezing.


.Short Term…(This evening through Thursday)
Issued at 315 PM EST Wed Nov 16 2022

After some sunshine filtering through this afternoon as drier air set in, we will see low level clouds move over central KY from the west. Breezy westerly winds will eventually die down by this evening as daytime mixing diminishes, but west winds should remain between 5- 10 mph overnight. We are currently located underneath broad upper troughing, with another subtle shortwave expected to pass through the Ohio Valley tonight. Several hi-res CAMs have been hinting at a quick moving wave of wintry precip this evening as a vort lobe swings through. Model soundings show a shallow layer of moisture tapping into the DGZ this evening, with steep low level lapse rates but a decent dry layer at the sfc will likely limit most precip chances. No accumulations are currently expected, though should we be able to tap into more moisture, the steep lapse rates will result in brief snow showers that could result in very light accumulations. Not entirely confident on this, but given the broad ascent over the area it is possible. Will blend hi-res guidance to highlight an area of sprinkles/flurries for a short period mainly across central KY tonight. Lows for tonight will drop down into the low to mid 20s.

For tomorrow, the upper flow flattens into a more zonal pattern. A dry forecast is expected for tomorrow, with the greatest cloud coverage expected along and north of I-64. With this in mind, cooler high temps are expected across southern IN, with mid 30s possible. Temps closer to 40 are expected to the south across Kentucky.

.Long Term…(Thursday night through Wednesday)
Issued at 300 PM EST Wed Nov 16 2022

Thursday Night – Sunday…

A cold front will bring a reinforcing shot of cold air to the region for the weekend. Expect unseasonably cold temps with highs in the 30s to low 40s and low temperatures in the teens and low 20s Fri- Sat-Sun.

In addition to the cold air, the front could also bring a few flurries/sprinkles to the area late Thu night into Fri morning but feel the majority of the model soundings are too dry to mention any precipitation in the forecast attm. Sat-Sun look dry with sfc high pressure moving in from the west.

Monday – Wednesday…

By Monday, return flow should commence as the high pressure moves eastward out of our area. This will result in a warming trend through mid week. High temps will moderate into the 40s for Mon with 50s for highs by Tue/Wed.

12Z long range models indicate an upper level shortwave could bring a slight chance for precip to the area Tues. However, the best chance for the return of rain should come Wed-Thu ahead of a potent low pressure system over the central U.S.


.Aviation…(00Z TAF Issuance)
Issued at 640 PM EST Wed Nov 16 2022

Local WSR-88D, observations as well as traffic cameras across southern IN and northern KY have shown pockets of light snow and flurries this evening but with dry air below 3000ft, it has been a challenge for any of this precipitation to reach the ground. Given this trend and upstream reports, decided to go with vicinity showers for snow and flurries through the first part of the forecast cycle. Winds were also breezy out of the west up to 10kts. Winds will die down some overnight and our mid-level cloud deck should break up a bit later tonight into early tomorrow morning with mostly clear skies. Models suggest a slight increase in clouds just before dawn tomorrow morning with CIG between 2500-3000 which would put them into MVFR categories. Confidence right now is low on this so went with the mention of SCT clouds at this level. The overall thought for this TAF cycle is VFR conditions with moderate to high
confidence. Will have to monitor through the first few hours for the forecast for possible light snow showers, then tomorrow morning for more BKN/OVC MVFR CIG.




Short Term…CJP
Long Term…AMS