Forecast Discussion
852 FXUS64 KMEG 182350 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 550 PM CST Sun Jan 18 2026 ...New AVIATION... .KEY MESSAGES... Issued at 550 PM CST Sun Jan 18 2026 - Cold and dry conditions will continue through Tuesday morning. The coldest wind chills are expected early Monday morning, dropping as low as 10 to 15 degrees north of Interstate 40. - Temperatures will moderate by Tuesday afternoon, with highs reaching the upper 30s to mid 40s. - Light rain will spread into the Midsouth on Wednesday, ahead of cold frontal passage Wednesday night. Very light snow or sleet could occur over northwest Tennessee Wednesday morning, before changing over to light rain. && .DISCUSSION... (This afternoon through next Saturday) Issued at 1151 AM CST Sun Jan 18 2026 Through midweek, the upper level pattern will be characterized by a broad longwave trough over the eastern CONUS, downstream of ridging along the west coast. During this period, gradual deamplification will occur, resulting in zonal flow over the lower MS River valley by Tuesday. At the surface, southerly low level return flow and milder temperatures will arrive Tuesday afternoon. The pattern deamplification will result in a more favorable fetch of midlevel southern branch moisture, ahead of a northern branch shortwave trough. Model consensus depicts this system arriving about six hours earlier than yesterday`s models depicted, led by 06Z ECMWF members and reflected in today`s 12Z operational GFS. Besides an earlier onset of rain showers Wednesday, the implications for the Midsouth include a brief chance of light snow or sleet over northwest TN Wednesday morning. At this time, moisture appears to be modest and confined to the midlevels. As such no winter precipitation accumulations are expected prior to a changeover to light rain toward midday on Wednesday. The faster precipitation timing should result in limited mixed precipitation chances Wednesday night, with most precip ending by time post-frontal thermal profiles become favorable for wintry precip. For Friday and early Saturday, model consensus remains fairly tight with respect to maintaining zonal flow over the Midsouth. By day 8 (Sunday), 00Z/06Z model consensus begins to break down with respect to southern branch energy off the west coast, and downstream moisture across the southern plains and lower MS River valley. The takeaway: the forecast for next weekend may be in flux for a few days. && .AVIATION... (00Z TAFS) Issued at 550 PM CST Sun Jan 18 2026 High confidence for VFR conditions persisting through the period at all sites. Southwest winds will veer west/northwest and increase in speed tonight as another reinforcing cold front moves through the Lower Mississippi Valley. LLWS mention was kept in TAFs as 2 kft winds will increase to 35-40 kts. && .FIRE WEATHER... Issued at 1151 AM CST Sun Jan 18 2026 Very dry polar air will prevail over the Midsouth through Monday. Despite much colder than normal temperatures, minimum relative humidity will range from 25 to 35 percent through the period. Temperatures will moderate on Tuesday, but moisture return will lag, resulting in minimum relative humidity of 20 to 25 percent over much of the Midsouth Tuesday afternoon. Low chances of wetting rainfall return Wednesday, followed by moderate minimum humidity levels late in the week. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...PWB AVIATION...CJC