Forecast Discussion
889 FXUS64 KMEG 212349 AAA AFDMEG Area Forecast Discussion...UPDATED National Weather Service Memphis TN 649 PM CDT Tue Apr 21 2026 ...New AVIATION... .KEY MESSAGES... Issued at 649 PM CDT Tue Apr 21 2026 - Elevated fire danger will occur across the entire Mid-South today due to a combination of elevated winds, low humidity, and dry vegetation. - Warm and dry conditions with highs in the low to mid 80s will continue through Thursday, though relative humidity will edge higher each day. - Warm and humid conditions will prevail Friday through the weekend. Shower and thunderstorms will peak near 90% on Friday and remain in the 30-50% range through the weekend. && .DISCUSSION... (This evening through next Monday) Issued at 1237 PM CDT Tue Apr 21 2026 The latest surface analysis places high pressure over the SE CONUS with low pressure over southern Texas and the West Coast. Aloft, GOES East Water Vapor Imagery reveals northwest flow across the eastern half of the country with a shortwave over the Southern Plains and a large cutoff low just off the PAC NW coast. Surface winds will remain elevated across the Mid-South this afternoon due to a tightened pressure gradient across the Lower Mississippi Valley. Elevated fire danger will continue through late afternoon as relative humidity drops below 30%, southerly wind gusts approach 25 mph, and vegetation remains very dry. Upper level high pressure will continue to build over the central CONUS through late week as the upper low slowly moves into the Intermountain West. This will lead to above normal temperatures and dry conditions for the majority of the country including the Mid-South. Moderate return flow will advect in Gulf Moisture through late week resulting in higher dew point temperatures each day, which will lower fire danger across the region. Unsettled weather will begin Friday as the aforementioned upper low expands and impinges on the Lower Mississippi. Loosely organized thunderstorms and showers are expected each day as bulk shear remains below 30 knots. The ECMWF ESAT depicts PWATs at or above the 90th percentile Friday through next Tuesday. This will keep the Mid-South in a moist and unstable air mass with medium to high potential for heavy rainfall each day. The latest LREF guidance shows multiple weak shortwaves traversing the Lower Mississippi this weekend. This will keep at least 30 to 50 PoPs in the forecast over the weekend. LREF guidance is consistent with a more robust shortwave emerging in the Plains on Monday with a surface low and attendant cold front moving across the Mississippi Valley. This supports more organized thunderstorms for which SPC has added a Slight Risk (2/5) for the entire Mid-South next Monday. It is a little early to sort out details at the day 6/7 timeframe, but if both the ensembles and operational models continue this trend, confidence will increase. At the very least, much needed rainfall will impact the region. AC3 && .AVIATION... (00Z TAFS) Issued at 649 PM CDT Tue Apr 21 2026 VFR will continue through the next 30 hours. Some midlevel moisture between FL060 and 080 will edge up from the Arklamiss, along with some underlying cumulus around JBR Wednesday afternoon. && .FIRE WEATHER... Issued at 1237 PM CDT Tue Apr 21 2026 Fire weather danger will decrease on Wednesday as winds relax and relative humidity gradually moderates into the 30 to 35% range. Relative humidity will increase further on Thursday in advance of an approaching cold front. Medium to high chances for wetting rainfall returns Friday through the weekend. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...AC3 AVIATION...PWB