textproduct: Memphis

KEY MESSAGES

Issued at 630 AM CDT Tue Aug 18 2026

- A Heat Advisory remains in effect through Tuesday for portions of eastern Arkansas and north Mississippi.

- Heat is expected to persist through Wednesday over portions of the Mid-South with little if any relief expected until a cold front moves through the area later this week.

DISCUSSION

(Tonight through next Monday) Issued at 1126 PM CDT Mon Aug 17 2026

00Z upper air analysis centers an 597 dm ridge axis over portions of the southwest U.S. and the Southern Plains. Meanwhile, the Lower Mississippi Valley is now within northwest flow aloft. Latest surface analysis shows a weak quasi-stationary boundary bisecting the Lower Mississippi Valley from Middle Tennessee back through north Mississippi and southern Arkansas. Warm and humid air remains in place across the Mid-South this evening with temperatures and dewpoints in the 70s.

Rainfall from late afternoon convection over north Mississippi has produced conditions favorable for the development of patchy fog overnight. The weak front is expected to settle near the southwestern edge of the forecast area into Tuesday. Short-term CAMs indicate a low potential (<20% chance) for isolated showers and thunderstorms overnight into Tuesday morning west of the Mississippi River in association with a weak shortwave over western Arkansas. Very hot temperatures in the middle 90s to approaching 100 degrees are expected again across the area mostly along and south of a line from Jonesboro to Tupelo, including the Memphis metro area. However, slightly drier air will keep heat index values below advisory criteria to an extent across the area with the exception of portions of north Mississippi bordering central Mississippi and east Arkansas south of I-40. A Heat Advisory remains in effect across this aforementioned area with the addition of Chickasaw and Monroe counties in Mississippi through 8 PM Tuesday. Latest short-term trends suggest any convective development may remain just to the south and west of the area on Tuesday during peak heating.

The aforementioned surface boundary is expected to return back north as a warm front Tuesday night into Wednesday with higher dewpoint air returning across the area. This more humid air combined with temperatures near or exceeding 100 degrees may necessitate the issuance of a Heat Advisory across much of the Mid-South on Wednesday with heat index values approaching 109 degrees.

By Wednesday, a series of mid-level shortwaves embedded within northwest flow aloft will drop into the Lower Mississippi Valley into Thursday. A large variance in solutions exists during this period with the NAM suggesting weakening convection dropping into the Mid-South during the day Wednesday and dissipating with GFS and ECMWF solutions hinting at convection developing towards Wednesday evening. Overall shear at this time appears to be weak across the region with more favorable shear occurring north of the area. This will continue to be monitored as additional data arrives into Tuesday.

Thankfully, deterministic and ensemble solutions remain in good agreement with a mid-level trough settling across the eastern U.S later this week into the upcoming weekend. This will bring slightly cooler and drier air to the area through at least the weekend.

AVIATION

(12Z TAFS) Issued at 630 AM CDT Tue Aug 18 2026

VFR expected at MEM/JBR/MKL through the period. TUP could see MVFR visibilities from mist through the first couple hours of the TAF, but will also otherwise be VFR through the period. An area of rain showers over east-central Arkansas will continue east through the beginning of the TAF period, eventually making its way to MEM. However, coverage is expected to dwindle by that time with only enough coverage to warrant VCSH. Winds will start out northeasterly, backing to a more northerly direction throughout the day, then begin to veer southerly through the end of the TAF period after 00z Wednesday.

FIRE WEATHER

Issued at 1126 PM CDT Mon Aug 17 2026

Fire danger is expected to remain low through the period due to light 20 ft winds, although minimum relative humidity values may drop below 40% in some areas on Wednesday. Fog potential remains low due to dry soils with the exception of north Mississippi Tuesday morning due to recent localized rainfall.

MEG WATCHES/WARNINGS/ADVISORIES

AR...Heat Advisory until 8 PM CDT this evening for ARZ049-058.

MO...None. MS...Heat Advisory until 8 PM CDT this evening for MSZ007-010>012- 020>024.

TN...None.