751 FXUS64 KMEG 261739 AAA AFDMEG Area Forecast Discussion...UPDATED National Weather Service Memphis TN 1139 AM CST Sat Dec 26 2020 .UPDATE... Updated for 18Z Aviation Forecast Discussion below. && .PREV DISCUSSION... /issued 1046 AM CST Sat Dec 26 2020/ DISCUSSION...Surface analysis late this morning places a 1028 mb ridge of high pressure centered over Southern Alabama late this morning. This is resulting in sunny skies and temperatures as of 10 AM CST in the upper 30s to middle 40s. Southerly winds on the back side of high pressure will help to moderate temperatures back into the upper 40s near the Tennessee River and lower to perhaps middle 50s elsewhere this afternoon. Overall forecast in good shape and no updates anticipated at this time. CJC PREV DISCUSSION... /issued 530 AM CST Sat Dec 26 2020/ UPDATE... Updated for the 12Z Aviation Discussion PREV DISCUSSION... /issued 330 AM CST Sat Dec 26 2020/ DISCUSSION... Southerly winds have resumed across the Mid-South early this morning, but northwesterly flow aloft continues as the deep eastern trough traverses the Mid-Atlantic states. A split flow pattern over the west will translate east, damping the ridge over the Mountain West and resulting quasi-zonal flow aloft tonight as the shortwave trough over the Southern Plains passes to our south. Warm advection is already underway across the CWA with temps holding steady or even warming slightly the remainder of the night. Notably warmer conditions are anticipated this afternoon with highs at or above climatology, mainly in the low/mid 50s. A low-level jet will intensify tomorrow evening as a shortwave trough ejects into the Plains. Stronger surface winds will keep the boundary layer well mixed with temperatures in the mid/upper 30s in most areas. The normal colder areas in west TN and northeast MS may still dip below freezing for a few hours. A surface low will move quickly toward the Great Lakes, dragging a cold front into the Mid-South Sunday evening. Above normal temperatures will continue for Sunday ahead of this cold front with highs in the upper 50s and lower 60s. A progressive shortwave trough will bring a quick round of light rain showers Sunday evening, ending by Monday morning. Moisture with this system isn't very impressive and QPF will remain light at less than 1/10" in most areas. Benign weather is anticipated in the wake of this wave as a trough digs over the western CONUS late Sunday with shortwave ridging developing downstream over the middle of the country. A strong jet streak over the OH Valley should provide some high clouds during this period which should help keep temperatures near climatology both Monday and Tuesday. The aforementioned western trough will move slowly east through the midweek period and will provide our next substantial rainfall. Warm advection ahead of this trough could initiate rain showers as early as Tuesday night with PoPs increasing from west to east during the day Wednesday. The greatest rain chances will be Wednesday afternoon into the overnight period as strong forcing for ascent combines with lift along the attendant cold front. As stated yesterday, while kinematics will be strong with this system, there isn't a lot of instability to work with so the potential for thunderstorms will be limited and remain confined to north MS at this time. Rain may mix with or change over to light snow early Thursday morning as cold air spills into the region, but it's more likely that the moisture moves east too quickly. A slightly slower frontal passage offered by some of the ensemble guidance suggests the cold air may be a bit delayed. In addition, moisture aloft may be shunted east which could shut off dendrite formation. With that in mind, the potential for snow was trimmed back and only affects a portion of the area, mainly north of I-40. Regardless, we don't anticipate any accumulation should this transition occur. Total rainfall amounts with the midweek system look to average between 1-2" but higher amounts are certainly possible. Dry weather is expected New Year's Day with temperatures slightly below normal heading into the weekend. MJ && .AVIATION... 18Z TAFs VFR to continue on the back side of the retreating Arctic high pressure. Southerly gust potential will increase a few hours following sunrise Sunday. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$