Forecast Discussion 15:19:04.7290

.Short Term…(This evening through Tuesday)
Issued at 300 PM EST Mon Nov 14 2022

Relatively quiet weather across the region this afternoon as surface high pressure departs to the northeast. Mostly sunny skies have prevailed, although we are beginning to see increasing high clouds across southern KY. Surface observations reveal temperatures have warmed into the mid to upper 40s so far, with a few locations dancing around the 50 degree mark.

As we move through this evening, a compact shortwave that is currently traversing the TX Panhandle will begin to lift
northeastward, swinging through the OH Valley during the day Tuesday. Cloud cover will begin to increase across the area this evening ahead of the approaching system, with cloud decks gradually lowering overnight. Precipitation will then begin to overspread the area from SW to NE in the pre-dawn hours and continue through the morning before pushing off to the northeast during the afternoon.

In general, temperatures are expected to be in the mid to upper 30s as the precipitation moves in early Tuesday morning, with some locations nearing the freezing mark. Model soundings indicate saturation will extend into the DGZ, with snow then melting as it falls through the warmer near-surface layer, reaching the ground as rain. However, in areas that are hovering closer to 32 degrees, evaporative cooling in any heavier precipitation rates will likely be enough to mix in some snow. Best chances to see a wintry
rain/snow mix will be across southern IN and north-central KY into the Bluegrass region, but do not expect more than perhaps some very light accumulations. And while road temperatures are generally expected to remain above freezing, cannot rule out some slick spots developing in the morning along bridges and overpasses. As
temperatures warm into the lower to mid 40s by the afternoon, expect rain to be the only p-type by mid-morning.


.Long Term…(Tuesday night through Monday)
Issued at 310 PM EST Mon Nov 14 2022

We will begin the long term period with a broad upper level trough over the central US. At the sfc, high pressure located over TX/OK will be nosing into the Bluegrass State. Upper level troughing will keep general cloudiness over our region for much of Wednesday, helping to keep temps in the low 40s throughout the day. A quick- passing shortwave looks to tap into shallow low level moisture and provide enough support in a below-freezing column to result in some very light snow chances for Wednesday evening and overnight. Model soundings show saturation mainly below 700mb for areas along and north of the I-64 corridor, with slightly drier air to the south. Limited moisture will result in mostly flurries along and north of I- 64, though some measurable snow is not out of the question. Some, but not majority, of EPS and GEFS members pick up on some minor snow accumulations. Additionally, NBM projects a 34% probability of SDF receiving more than 0.01″ of snow by Thursday morning. Over at LEX, NBM paints a slightly higher 42% probability of receiving more than 0.01″ of snow. Regardless, a dusting is expected with maybe some locally higher amounts topping out in the tenths. Impacts should be minimal given the expected minimal snow amounts and time being overnight.

With the trough axis swinging east by Thursday, should see sunshine slowly return from south to north through the day. The upper flow flattens out and becomes more zonal, and should have drier, but cool, weather in store for the rest of the work week. Friday brings a re-enforcing cold shot to the region as high pressure builds further east. Highs on Friday will range from the low 30s north of I- 64, to upper 30s down across the KY/TN line. Coldest air of the season thus far arrives Saturday morning, with gelid morning lows in the teens. Currently appears that it won’t be a record cold for most climate sites, though BWG would be the one if any to at least tie their current low record for 11/19. BWG’s record low for that day is 17F (1951), and current forecast is 18F. Will stick with mean NBM solution for now, but it’s worth mention that the 50th percentile NBM comes in a bit lower with min temps for Sun and Mon mornings.


.Aviation…(18Z TAF Issuance)
Issued at 1245 PM EST Mon Nov 14 2022

-Chance for precip and MVFR/IFR CIGs around daybreak Tuesday.


Expect VFR conditions to prevail through today and into the first part of tonight, with mid- and high-clouds gradually increasing this evening. As we move into the pre-dawn hours (15/10Z-12Z), ceilings will begin to lower from west to east into MVFR range as precip overspreads the area, with the potential for IFR CIGs by mid-late morning at all TAF sites. While precip looks to fall as mostly rain, certainly cannot rule out a wintry mix early Tuesday morning at KHNB/KSDF/KLEX as surface temperatures hover around the freezing mark. Confidence was too low to include mention of any -SN or freezing precip though. Precip will then push out of the area by early afternoon.




Short Term…JML
Long Term…CJP