729 FXUS64 KHUN 100820 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 220 AM CST Wed Jan 10 2024 ...New AVIATION... .NEAR TERM... (Rest of tonight) Issued at 934 PM CST Tue Jan 9 2024 Wrap around moisture streaming from a strong low pressure system over the Ohio Valley has resulted in periods of sleet and light snow across portions of north Alabama and southern middle Tennessee this evening. Expect this activity to come to an end over the next few hours as drier air filters into the region via drier northwesterly flow. Little to no accumulations are expected, with the highest chances for a dusting in the higher elevations of northeast AL and southern middle TN. With temperatures above freezing, do not expect road conditions to deteriorate enough in these areas to issue an Advisory, but will still urge motorists to use caution when driving overnight and early Wednesday morning as patchy black ice cannot be ruled out. The Wind Advisory will be allowed to expire at midnight as gradient winds continue to weaken, but elevated winds overnight should help mitigate lingering moisture on the roadways. Overnight lows will fall near or just below freezing, with wind chills bottoming out in the lower 20s to upper teens. && .SHORT TERM... (Wednesday through Thursday Night) Issued at 220 PM CST Tue Jan 9 2024 High pressure will build over the Southeast for midweek, leading to clearing skies and no rain chances through Thursday. Highs will be on an upward trend, beginning in the 40s on Wednesday and warming into the 50s by Thursday. Forecast lows follow a similar pattern, with low to mid 30s expected Wednesday night and upper 30s to mid 40s Thursday night. The high will be pushed to the northeast as another low pressure system develops and moves over the ArkLaTex region Thursday night. This system will bring increased chances (30-60%) of rain to the Tennessee Valley late Thursday night into early Friday morning. Also, a tightening pressure gradient from the approaching low will lead to increasing winds late Thursday night into early Friday. Further details for this system Friday into Friday evening are discussed below. && .LONG TERM... (Friday through Monday) Issued at 326 AM CST Tue Jan 9 2024 [220PM Update] Little has changed with regards to the extended forecast. However, forecast rainfall amounts have trended downward to between 0.5-1.0 inches for the Friday system. Furthermore, confidence is increasing that the weather pattern will drastically change early next week. The Climate Prediction Center has outlooked the Tennessee Valley in a high chance (80-90%) for very cold temperatures early next week. As the previous shift mentioned, another system is slated to progress over the region early next week and bring the potential for winter precipitation. We will continue to monitor model trends over the coming days to better resolve details in timing and evolution of the system, as well as winter precipitation concerns. A vigorous shortwave trough will quickly shift from central Texas Thursday night into the lower Mississippi Valley by midday Friday and eventually eastern Kentucky by Friday evening/night -- with a rapidly deepening surface low moving from the Mid South into the lower Ohio Valley. Ahead of this feature, deep southerly flow will advect in a very moisture rich air mass from the Gulf of Mexico as evidenced by PWATs climbing into the 1.1" to 1.3" range (90th to 95th percentile per BMX/OHX sounding climatology. The stage will be set once again for efficient rain producing convection across the Tennessee Valley Friday morning through Friday evening. The fast movement of this system has cut back QPF amount from the system earlier in the week -- with storm totals of about 1" in most locations. Still some higher ensemble members do hint that we could out perform these values and at the very least some rises on rivers, creeks, and streams may occur due to the recently saturated soils. A glance at model soundings Friday afternoon indicates a very impressive shear profile. Bulk shear values of 60-70 kts and 0-1 km shear of 30-40 kts were noted -- with some impressive looping hodographs due to the strong directional shear as well. At the very least these values would favor strong gradient (non-thunderstorm winds) and the possibility for some organized elevated convection. Some serious questions about the storm environment and if a true warm sector can become established this far north. If it can and storms become surface-based, we'll have all the necessary ingredients for severe weather. However, confidence in this actually occurring is quite low with most ensembles favoring more favorable environment setting up to our south. Still something we'll have to monitor closely in the coming days, but for now will continue to message a few strong elevated strong storms for now -- and mainly focus impacts on rainfall and gradient winds. We will dry out Friday night into Saturday as a modified arctic air mass arrives in wake of the front passage. However, we may get clipped with some wrap around moisture Friday night, which could result in a brief window of rain mixing with light snow Friday evening. Otherwise, we'll dry out for the weekend and his will mean cooler weather with highs in the low to mid 40s and lows in the low to mid 20s. The next system to watch will take shape early next week as a deepening upper-trough along the Gulf Coast swings northeast into the southern Appalachians of GA/TN/NC. A lot of details to work out with this system, specifically with respect to the timing, track and evolution for next Monday and Tuesday. Long range ensembles are starting to point to some much colder air attempting to work in behind this system -- and potentially a combination of rain and light wintry precipitation just ahead of the cold front. Again, still a long way out and a lot of details to work through -- but something we will definitely have to monitor. && .AVIATION... (06Z TAFS) Issued at 220 AM CST Wed Jan 10 2024 MVFR to VFR cigs are persisting across the area during the overnight hours before clearing Wednesday morning and VFR conditions will prevail. Gusty west to southwesterly winds will persist through tomorrow afternoon, gradually lessening with time. Wind gusts up to 30-35kts cannot be ruled out during the overnight hours. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...25 SHORT TERM....26 LONG TERM....AMP AVIATION...AMP.24