Forecast Discussion
660 FXUS64 KMEG 121727 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1127 AM CST Fri Dec 12 2025 ...New DISCUSSION, AVIATION, FIRE WEATHER... .KEY MESSAGES... Issued at 1127 AM CST Fri Dec 12 2025 - Arctic air will bring the coldest temperatures of the season from Saturday night through Monday morning, with wind chills dropping into the teens and single digits Sunday and Monday mornings. - Temperatures will warm quickly to near-normal by Tuesday, increasing rain chances for the middle of next week. && .DISCUSSION... (This afternoon through next Thursday) Issued at 1127 AM CST Fri Dec 12 2025 A deep upper trough continues to traverse the northeastern CONUS with a longwave ridge centered over the Pacific Coastline. The Mid-South, positioned between the two features, will remain in a northwesterly upper regime to start the forecast. Weak surface troughing over the region will travel east today, bringing a cold front down behind it. Precipitation is not expected with both the surface low and the front as upper air profiles, both observed and modeled, show a moisture-starved atmosphere. Therefore, the forecast will remain dry and temperate today with highs ranging from the upper 40s along the TN/KY border to the low 60s in northern Mississippi. A second cold front, currently over the northern Plains, will travel south tonight and into tomorrow. This front will eventually overtake the Mid-South Saturday evening and through the night into Sunday, bringing a bitterly cold, arctic air mass in its wake. A few rain showers are possible (~30% chance) over northern Mississippi just ahead of the front, but any rain will be light with no wintry precipitation expected. The frontal passage is expected to be quick with a strong temperature drop from highs in the 40s and 50s, down to temperatures below 30 F. Both the HREF and NBM mean outputs bring sub-20 degree temperatures across the northern third of the area with at least a 50% chance of sub-20 degree temperatures as far south as Jackson, TN Sunday morning in both model suites. Alongside the cold air, a strong pressure gradient and accompanying low-level jet will produce gusty winds in excess of 20 mph in most places. This will bring wind chill values into the single digits as far south as the TN/MS border with some locations in our northern counties flirting with 0 F wind chills Sunday morning. Therefore, a Cold Weather Advisory may be necessary across portions of Western Tennessee, but HREF guidance only brings a 50% chance of these areas reaching their respective Cold Weather Advisory thresholds (0 F and 5 F). Cold air will continue through Sunday as a strong 1040+ mb surface high moves across the Midwest and into the Ohio River Valley, effectively forcing additional cold air advection throughout the day. With diabatic heating being offset by the strong advection, temperatures will struggle to reach above freezing across the majority of the region Sunday afternoon. Areas north of I-40 will be even colder with areas along the TN/KY border currently having a 60%+ chance of highs not even getting to 20 F, an impressively cold air mass for this area. Monday morning has the opportunity to be even colder as the center of cold air mass reaches the region Sunday night into Monday. Areas east of the Mississippi river, barring the delta across northern Mississippi, will have a 60%+ chance of lows below 15 F. However, pressure gradient winds and the low-level jet will have died down by this point in the forecast, with higher confidence in wind chills remaining above Cold Weather Advisory criteria. And with weaker cold air advection, diabatic heating should allow the majority of the region to warm above freezing throughout the day. High pressure will then move off to our east and allow southerlies to return to the forecast, warming the region considerably through the middle of next week. By Tuesday afternoon, highs will already be in the mid to upper 40s with lows in the 20s and low 30s, warming highs further on Wednesday into the 50s and 60s. At the same time, ensembles suggest the upper pattern will de-amplify and become nearly completely zonal, letting further warming commence through the end of the week with a mostly dry forecast. Forecast confidence remains high well past the end of the period with GEFS members keeping zonal flow through at least 240 hours. The only discrepancies are the position and amplitude of weak shortwave disturbances within the zonal belt of westerlies, which would have the ability to create higher precipitation chances. So, forecast confidence is high that we will warm through the middle of next week with lower confidence on when our next precipitation chances will be after this weekend. && .AVIATION... (18Z TAFS) Issued at 1127 AM CST Fri Dec 12 2025 Confidence is high (90-100%) for VFR conditions and no precipitation through this evening as a cold front moves through the region. Winds continue to veer through the 24-30 hour TAF cycle and may gust a bit this afternoon with the frontal passage. Winds will become light (around 5kts) tonight and calm by midday tomorrow as high pressure approaches from the north. The HREF has a medium chance (30-40%) of post-frontal low clouds developing overnight at MKL but the NBM keeps clouds farther north. && .FIRE WEATHER... Issued at 1127 AM CST Fri Dec 12 2025 A slight increase in moisture due to southerly winds should keep minimum relative humidity values above 30% this afternoon. An arctic cold front will cross the area Saturday evening bringing very dry and cold air. Minimum RH values beginning Sunday will hover around 30%. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...JAB AVIATION...JDS