Forecast Discussion
020 FXUS64 KMEG 202328 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 528 PM CST Tue Jan 20 2026 ...New AVIATION... .KEY MESSAGES... Issued at 528 PM CST Tue Jan 20 2026 - An impactful winter storm is expected to impact the Mid-South beginning Friday afternoon with heavy snow, sleet, and ice accumulations expected through Sunday morning. - Bitterly cold air will accompany wintry precipitation, lasting into early next week. Wind chills will be in the teens and single digits. - Light rain is expected across the region Wednesday with only a quarter to a half-inch of rain accumulation expected. There is a low (less than 20%) chance of wintry precipitation. && .DISCUSSION... (This evening through next Monday) Issued at 108 PM CST Tue Jan 20 2026 Calm weather is forecast to continue through today as upper troughing over eastern Canada keeps northwesterly flow aloft across the central and Eastern CONUS. A shortwave embedded in this flow, currently over British Columbia, will dive southeast and bring a cold-frontal passage tonight. Precipitation chances will increase along and ahead of the front with rain showers expected to begin around sunrise Wednesday across eastern Arkansas, spreading east throughout the day. Some models have attempted to bring some wintry precipitation, mainly in the form of light freezing rain or snow showers, across eastern Arkansas tonight. However, HREF ensemble sounding plumes show a significant majority of members keep SFC - 850 mb wet bulb temperatures above freezing, eliminating serious concerns for wintry precipitation through sunrise. After sunrise, surface temperatures will increase well above freezing with rain expected across the rest of the region. Precipitation amounts will be light with only .25" - .50" of rain accumulation across the region at most. Rain associated with Wednesday`s frontal passage is expected to end by sunrise Thursday as the front moves east of the region. Dry weather will then shortly prevail through Thursday as surface high pressure slides in behind the front with mild afternoon temperatures. Upper troughing will struggle to budge across the eastern half of the continent with another shortwave propagating around the western side of the trough Thursday night. Another cold front, much stronger than the one Wednesday, will then move south across the Midwest into Friday. By Friday morning, the cold front will reach the region, quickly dropping temperatures below freezing by mid-afternoon. Behind the front, a strong, 1045+ mb high will seep its way into the northern CONUS, effectively locking in the cold air at the surface. Continued CAA from the high pressure will then decrease temperatures further Friday night with air temperatures dropping into the 10s and 20s alongside wind chills in the 10s and single digits. Moisture depth will be lacking, particularly near the surface owing to the arctic nature of the front through the majority of the night. This should keep the region dry Friday morning, but this will quickly change as the day progresses. While the latter-week cold front traverses the country, a lobe of energy will descend across the Pacific Coastline, creating a mostly-cutoff upper low off the coast of California. This system will allow for downstream advection of upper moisture over Mexico and into the southern CONUS. The arrival of moisture will time optimally to begin interacting with the cold front aloft Friday. Therefore, most medium to long range guidance begin isentropically lifting this moisture and producing precipitation as early as Friday afternoon, only increasing in intensity through Friday night. Thermal profiles Friday will be characterized by an increasingly deep cold layer at the surface with remnant above- freezing temperatures between 850 mb - 700 mb. In this environment, all modes of wintry precipitation are expected, including snow, ice, and sleet. Through Friday night, the upper trough off the west coast will begin to phase with another shortwave entering the northwestern CONUS, which will begin to pull it east. Upstream amplification of both upper heights and wind will increase low level theta-e advection from the gulf north into Saturday. Models had struggled with the development of a surface low in past runs, but ensembles and deterministic guidance alike now have a distinct area of surface low pressure developing south of the region Saturday. All of these factors combined will only serve to increase the forcing and moisture available for precipitation Saturday with an expansive precipitation shield occupying the entire region, setting the stage for an impactful winter storm. The details have begun to come into better view with respect to the impacts that can be expected from this system. Yesterday, the GFS and ECMWF differed significantly regarding the magnitude of QPF across the Mid-South. However, these issues have been rectified overnight with both deterministic models agreeing that a swath of 6+ inches of snow is probable along I-40 alongside the potential for significant sleet or ice across northern Mississippi. The main questions that are yet to be answered are: 1) where will the heaviest axis of snowfall reside and 2) will sleet be favored over freezing rain over north Mississippi. Regarding snowfall, NBM and LREF have increased their snowfall probabilities, particularly along and north of I-40, for 3"+ (50%- 70%) and 6"+ (30%-50%). South of the snowfall axis, both aforementioned models have a 30% - 50% chance of at least a quarter-inch of ice. As listed above, ice could very well become a large area of sleet and will depend on the depth of the cold layer behind the cold front and how far south it manages to make it before the upper moisture arrives. Models are split down the middle still between the two, but one thing can be for sure: significant impacts can be expected from both regardless of whether impacts are related to road (sleet) or power (ice) infrastructure. Forcing and moisture will lessen into Sunday with most guidance kicking any precipitation out by early Sunday afternoon. Temperatures will remain very cold with temperatures below freezing through Monday at least and wind chills in the teens and single digits. Therefore, any wintry precipitation will struggle to melt and recovery efforts may be hindered through the middle of next week. Luckily, the forecast remains dry through this time frame, regardless of the cold. && .AVIATION... (00Z TAFS) Issued at 528 PM CST Tue Jan 20 2026 Impactful aviation weather will emerge this evening as LLWS develops at FL020 ahead of an approaching upper level trough. Scattered SHRA will develop around 10Z in the airspace, oriented just ahead of a cold front. LLWS will dissipate by midday with showers clearing from west to east. Guidance continues to develop IFR/LIFR CIGs at all sites after 18Z. As such, introduced lower cloud groups through the remainder of the period. ANS && .FIRE WEATHER... Issued at 108 PM CST Tue Jan 20 2026 Dry, arctic air will remain through this afternoon with relative humidity values anywhere from 20 to 30 percent, although 20 ft winds will remain below 10 knots. A cold front will reach the Mid- South tonight and bring wetting rains and higher humidity values through this weekend. Expect accumulating wintry precipitation beginning Friday that will last through the majority of this upcoming weekend. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...JAB AVIATION...ANS