Forecast Discussion 18:13:37.7998

…Updated Aviation Discussion…

.Short Term…(This evening through Monday)
Issued at 300 PM EST Sun Nov 13 2022

The stratus deck has had trouble clearing across much of the area today, thanks in large part to redevelopment of stratocu in places where we did get brief clearing. This can happen with reinforcing cold advection in the cloud layer which is what we’ve been seeing on satellite imagery. This will ultimately keep highs from reaching full potential, and as a result we expect almost everyone to stay in the mid to upper 30s for highs.

Do think we’ll eventually see some clearing in the lower levels this evening, however will also have the arrival of some upper clouds into the overnight. This may offset the full radiational cooling component overnight, but still expect things to get quite chilly given highs today only in the 30s. Most spots should find their way into the low and mid 20s, with the coolest valleys likely seeing the upper teens for lows.

Surface high pressure centered to our NE continues to have influence over our region tomorrow, however will begin to lose hold over the area as it centers in the eastern Great Lakes. Our winds will veer from NE to E as this occurs, a typical cool setup when it comes to high temperatures. Given that and lingering high clouds, went a little below NBM for tomorrow. Otherwise, expect dry conditions with highs mostly in the 40s. A few spots may reach 50 across our south.

.Long Term…(Monday night through Sunday)
Issued at 305 PM EST Sun Nov 13 2022

The overall large-scale pattern continues to feature broad
troughiness across the eastern two-thirds of the CONUS. This will result in a couple of embedded shortwave disturbances moving through the region, notably Monday night into Tuesday and then a second weaker feature Wednesday night. Temperatures will also remain below normal by 10-15 degrees through the week and into the weekend.

Mid-level shortwave will be located over the lower MS Valley Monday night but quickly into western KY early Tuesday morning. Clouds will increase ahead of the feature with the bulk of the precipitation arriving after midnight through early Tuesday morning. The main forecast challenge remains precipitation type at the onset of the event. Temperatures initially start off near or below freezing across southern IN and the Bluegrass with above freezing
temperatures off to the southwest. Temperatures will likely remain steady overnight or even slightly rise a degree or two towards Tuesday morning. Model soundings show a steady drop in temperatures vertically with an initial dry layer near the surface at the start of the period. Across southern IN and north-central KY, snow is likely at the start with model soundings showing saturation in the DGZ. A rain/snow mix is likely across central KY with all rain closer to the KY/TN border. There is a small chance of freezing rain in more sheltered and protected valleys where a sub-freezing layer could be slow to erode as the warm air advects over the top. Precipitation will become all rain by mid/late morning from the south to the north as warm air advection completely scours out the cold surface layer. Overall impacts continue to be minimal as QPF is trending less than a tenth of an inch for most locations. Where we see mainly snow early Tuesday morning, only a dusting is expected with temperatures near or above freeze during the morning rush. Highs will continue to warm during the day with highs on Tuesday warming into the mid 40s.

The next disturbance comes out of the Dakotas Wednesday and quickly pushes through the Ohio Valley Wednesday night. Deterministic models have started to pick up on this feature and we’re starting to see more agreement and confidence that a few light scattered snow showers or flurries are possible. Decided to increase PoPs to slight category with a few flurries Wednesday night. Temperatures will be in the low 30s to upper 20s but QPF if very minimal so no more than a dusting is possible at this point.

The rest of the week will be dry and colder as reinforcing shot of cold air moves in from Canada Thursday into the weekend. Highs through Saturday will struggle to get out of the 30s with lows in the low 20s to upper teens.


.Aviation…(00Z TAF Issuance)
Issued at 613 PM EST Sun Nov 13 2022

-Low clouds this evening


Previously MVFR cigs have risen into the VFR range as of early this evening with light and variable winds being reported at the
terminals. Low clouds will likely linger through the evening hours before starting to lift and mix out overnight. In general, VFR cigs/vsbys are expected overnight with a light northeasterly wind. Further clearing is expected late tonight and early Monday with winds shifting to the east and east-southeast during the day.


Medium-high on all elements.




Short Term…BJS
Long Term….BTN