924 FXUS64 KOUN 280514 AFDOUN Area Forecast Discussion National Weather Service Norman OK 1114 PM CST Fri Nov 27 2020 ...New AVIATION... .SHORT TERM... (This evening through Saturday) Issued at 252 PM CST Fri Nov 27 2020 Water vapor channel imagery shows a closed low along the Arizona / New Mexico border, moving eastward toward the area. In CIRA ALPW imagery, deep moisture connection to the Pacific extends to the Texas Gulf coast region. The closed low isn't particularly strong and won't be effective at tapping substantial moisture, but modest moisture advection and isentropic ascent will occur and a band of precipitation will move into our far southwest counties by morning. This will continue to spread northeast through the day bringing generally light amounts. Low-levels are quite dry and will take time to saturate, so the shallow low-level inversion with sub-freezing temperatures should mix out before precipitation begins in western Oklahoma. If precipitation intensity is sufficient for cooling to wet bulb profiles, some snow could mix in even midday or early afternoon, but rain should be the predominate precipitation type. For any noteworthy snow, precipitation rates would have to be more significant than currently expected and the coldest/driest of the model guidance would have to occur. Models remain fairly consistent with track and strength of this closed low, with perhaps a slight northward shift per GEFS mean, and slightly less anomalous. If a deeper more anomalous low were present we would be more concerned about a deformation/TROWAL band on the northwest site. Meager amounts of moisture and ascent within this quadrant of the cyclone may be enough for very light precipitation lingering on Sunday, or at least clouds. Most locations should see 0.10-0.25 inches for storm total rainfall amounts. BRB && .LONG TERM... (Saturday night through next Thursday) Issued at 252 PM CST Fri Nov 27 2020 Late saturday night, a southeastward moving shortwave trough and associated cold front will move through. This will be accompanied but a surge of stronger northerly wind and somewhat colder temperatures, albeit upstream source isn't particularly cold. In fact, Monday we'll see temperatures ranging from the mid 40s in the east to mid 50s in the west, followed by downslope/warming to near normal across the area Tuesday in response to the next system. From this point forward, forecast details become unclear as predictability for this time range is below normal. Medium range deterministic and ensemble guidance continues to show an assortment of closed lows in different positions with different intensities. We have left the model blend (NBM) without edit. Given the blocking nature of the pattern, and deep moisture relegated to the south, if/when we were impacted by one of the closed lows, a significant/impactful precipitation event seems unlikely, and a anomalously warm/cold air mass may be hard to achieve. Therefore, near climo temperatures seem most likely. We'll know more with more time. BRB && .AVIATION... (06Z TAFS) Issued at 1105 PM CST Fri Nov 27 2020 Mid-level clouds continue to increase from the southwest this evening. There are some radar echoes across western Oklahoma, but expect that this will mostly be virga early Saturday morning with the low-level airmass still being dry allowing the precipitation to evaporate before reaching the ground. Increasing low-level humidity will advect into the area through the day Saturday bringing lower ceilings and increasing rain chances that will spread from southwest to northeast through the day. Ceilings will mainly be VFR overnight with MVFR and eventually areas of IFR ceilings increasing through the forecast period. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 32 50 38 52 / 0 30 60 10 Hobart OK 32 47 35 54 / 0 70 40 10 Wichita Falls TX 37 46 36 56 / 0 80 40 10 Gage OK 28 48 32 51 / 0 40 30 0 Ponca City OK 28 53 37 51 / 0 10 40 10 Durant OK 39 55 40 54 / 0 30 70 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...12 LONG TERM....12 AVIATION...26