505 FXUS63 KLMK 121753 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 1253 PM EST Tue Jan 12 2021 ...Updated Aviation Discussion... .Forecast Update... Issued at 1110 AM EST Tue Jan 12 2021 Things are quiet across the CWA at this hour, with the only real concern being the lingering stratus/stratocu and it's effect on temperatures this afternoon. Still pretty confident we'll see more and more sunshine as we get into the early to mid afternoon time frame as the HRRR and other data indicate the already thin cloud layer will break up. Already seeing some evidence of this on visible satellite imagery and an earlier PIREP out of LOU only had the cloud depth at 500 feet. Clouds will hang on the longest in the east, so have gone a bit more pessimistic for their highs. Now only looking at mid to possibly upper 30s for highs there. Elsewhere, still expecting highs to top out a couple degrees on either side of 40. No other changes planned at this time. && .Short Term...(Today and tonight) Issued at 300 AM EST Tue Jan 12 2021 Morning fog/low cloud IR imagery shows plenty of low stratus across the region. This stratus deck is building eastward a bit and will continue to do so through the overnight hours. The good news is that the back edge is making progress eastward. In areas where it has remained clear, temperatures have dropped into the mid-upper teens, with areas in the clouds remaining in the mid 20s. Based on satellite imagery, the back edge of the clearing should start to move into our western portions of the CWA over the next two hours and if the current speed continues, we should start to see clearing making it toward the I-65 corridor by 12Z or so. As the clouds move into our central and eastern areas, expect temps to bottom out in the mid-upper teens and then rise very slowly. Out west where it is currently in the mid-upper 20s, we expect temps to drop off a bit once the clouds clear out. So lows out there may also dip into the upper teens/lower 20s over the next few hours. For today, guidance suggests that the low cloudiness will continue scour out across the region with most places seeing mostly sunny skies by late morning and into the early afternoon hours. Highs on the day should range from 40-45 in most areas. For tonight, mostly clear skies are expected across the region with lows in the mid-upper 20s. .Long Term...(Wednesday through Monday) Issued at 249 AM EST Tue Jan 12 2021 Dry weather continues for Wednesday and Thursday as low level ridging extends into the OH Valley from a much larger area of high pressure over the southern CONUS. Expect variable mid and high cloud cover along with ample sunshine (especially Wednesday) as split flow aloft sees a weak shortwave along a ragged PFJ to our north and an upper low passes to our south. WAA and SW flow will result in highs each day in the upper 40s and lower 50s. Winds will be a bit breezy as the PGF tightens ahead of our next system, which will also result in increased cloud cover throughout the day Thursday. Well formed low pressure system drops south out of Canada into the Northern Plains and Upper Midwest by Thursday, which brings precipitation chances back to the OH Valley Friday and Saturday. P-type will be diurnally driven Friday with a light rain/snow mix possible at onset and later that evening. Models continue to suggest a low QPF event so not expecting much in the way of impacts. Most members of EPS (11/12Z run) show light 24-hour snowfall in our CWA, and GEFS members are about 50/50. GFS soundings do show steep lapse rates with sufficient moisture depth into the DGZ. So confidence is beginning to increase regarding chance of lingering light snow during the day Saturday on the back side of the upper level low. Again, little to no impacts are expected at this time as model QPF remains quite low. Long range models really begin to diverge Sunday and into the beginning of next week. GFS shows another cold front pushing through the area Monday whereas CMC and ECMWF keep the area dry under the influence of high pressure. For now will keep things dry. && .Aviation...(18Z TAF Issuance) Issued at 1253 PM EST Tue Jan 12 2021 The stratus deck is fading out quickly, and have started the TAF sites optimistic with the exception of LEX. Still have MVFR hanging on for another hour or so. Otherwise, look for VFR and steady SSW winds through today. There is some concern for fog development tonight, but confidence is low at the moment. Will see how well the airports are able to mix out the low level moisture before the sun sets this evening. Otherwise, look for continued VFR tomorrow (outside of any morning fog) with a steady SW wind between 10 and 15 mph. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...BJS Short Term...MJ Long Term....CG Aviation...BJS