Forecast Discussion
538 FXUS64 KMEG 221123 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 523 AM CST Fri Nov 22 2024 ...New AVIATION... .SYNOPSIS... Issued at 423 AM CST Fri Nov 22 2024 Cool and dry weather will continue today. Northwest winds will gradually weaken as high pressure approaches from the west. High temperatures this afternoon will only reach the lower to mid 50s. After a chilly night tonight, Saturday`s high temperatures will warm to within a few degrees of normal. Southerly winds will bring a warming trend, with daytime highs reaching the lower 70s over most of the Midsouth. A late Monday cold frontal passage will bring a brief chance rain, followed by cooler temperatures on Tuesday. Cool and rainy conditions appear likely for the Thanksgiving holiday. && .DISCUSSION... (Today through Thursday) Issued at 423 AM CST Fri Nov 22 2024 A highly-amplified and progressive pattern will prevail over the U.S. through the end of next week. Large temperature swings are expected over the Midsouth, but at this time, wintry precipitation does not appear likely. We start the forecast this morning with a deep 527dam 500mb low centered over the central/northern Appalachians, and upstream ridge over the Great Plains. As the upper low lifts out, the upstream ridge will deamplify and move into the MS River Valley by Sunday. Across the Midsouth, zonal flow aloft will overspread southerly return flow at the surface, bringing milder conditions. Temperatures will peak on Monday, ahead of an upper trough lifting through the middle and upper MS River Valley. An accompanying Pacific cold front will pass through the Midsouth late Monday. Prefrontal moisture will be sufficient to support scattered to numerous showers along the front, with PWAT briefly reaching 1.25 inches. Modest instability should limit thunderstorm coverage. Following fair and cooler conditions on Tuesday, the pattern gets more interesting for the latter half of next week. The upper flow appears split off the west coast, consolidating downstream over the Great Basin and southern Rockies. Both GFS and ECMWF models depict rain developing over the Midsouth late Wednesday and Thanksgiving holiday, aided by our position under the right entrance region of a northern branch jet streak and the left exit region of a southern branch jet streak. During this period, PWATs will most likely range from 1 inch near the MO bootheel, to 1.5 inches south of Tupelo, MS. Thermal profiles will be supportive of rainfall through the Thanksgiving Day afternoon. Model consensus is relatively high in ending precipitation with the passage of a midlevel trough and surface cold front Thursday evening. Fair and cool conditions will prevail next Friday and Saturday, possibly followed by a reinforcing cold front on the following Sunday. PWB && .AVIATION... (12Z TAFS) Issued at 523 AM CST Fri Nov 22 2024 Guidance continues to bring an area of low stratus into the airspace today, primarily impacting MKL. Impacts to other terminals will be dependent on how far southwest the deck pushes. Added low VFR CIGs in at MEM and TUP to account for this. Patchy fog may develop near JBR overnight as winds decrease. Otherwise, expect northwest winds through the period. ANS && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...PWB AVIATION...ANS