textproduct: Memphis

KEY MESSAGES

Issued at 12013 PM CDT Wed Aug 19 2026

- An Extreme Heat Warning and Heat Advisory remain in effect through 8 PM tonight, with heat index values expected to peak between 105F and 112F.

- A Marginal to Slight Risk for strong-to-severe thunderstorm threat exists tonight, primarily for damaging winds and a tornado or two. Ensure your weather alert notifications are enabled through the overnight period.

- A transition to a zonal/northwest flow regime late this week will bring drier air and cooler temperatures for the weekend, providing relief from the oppressive heat.

DISCUSSION

(This evening through next Tuesday) Issued at 1213 PM CDT Wed Aug 19 2026

A large cluster of showers and thunderstorms is ongoing across southern Kentucky as of 11 AM with a few showers and storms dipping into West Tennessee. This cluster will continue its E/SE propagation through the early afternoon ahead of another round of convection this evening. This cluster has prohibited a warm front from surging too far north which has allowed temperatures to not warm as rapidly as previous days with temperatures generally in the 80s and approaching 90 degrees. Areas being affected by convection are still much cooler with readings in the 70s. Once convection ends and the warm front clears the area, expect an influx of moisture and heat index values to rise above 105F, and 110F in some places. The Extreme Heat Warning and Heat Advisory will remain in effect until 8 PM.

A shortwave currently over northeast Kansas and northwest Missouri will slowly move towards the Mid-South and threaten strong to severe thunderstorms this evening into the overnight hours. Despite this threat being in the short term, details are still not concrete. Each subsequent CAM run delays the arrival of the shortwave into the hours after sunset which decreases surface based instability. HRRR soundings indicate the development of a stout cap around 850mb, which would prohibit intense surface based convection. Most nocturnal events this summer have been a bust, due to the nocturnal EML, but this event is a bit different in that shear will actually be present. The LLJ will ramp up and bring a 60 kt maxima across southern Kentucky. The HRRR and NAM suggests this maximum dipping into our northern zones, which could easily threaten damaging winds, despite the CAP. Due to the intensity of the LLJ, this also increases helicity at or above 200 m2/s2. The CAP does bring LCL values a bit higher than typically desired for tornadogenesis, but is very dependent on where the LLJ sets up. If the LLJ does swing into the northern zones, damaging winds and a tornado or two are the primary concerns. Residents are strongly urged to ensure their preferred weather alert method is active and audible overnight, given the primary threat occurring during sleeping hours. Rain rates will be intense due to greater than 2" PW values, but the progressiveness of this system (and days of consecutive dryness) should alleviate major flooding concerns.

Thursday during the daytime hours has trended drier on the 12z suite, but there is likely to be remnant outflow boundaries from the overnight storms that could result in diurnally driven thunderstorms. Wet microbursts would be the primary concern given the environmental parameters, with a Marginal Risk (level 1/5) for damaging winds generally along and south of I-40. Our southern zones have one more threatening day for heat, which could be cooler than guidance suggests if convection does develop, and another Heat Advisory will go into effect at 11 AM Thursday for heat index values up to 108F.

After Thursday, drier air will filter into the region behind a weak cold front and could be our first day without heat headlines as heat index values are expected to fall below 105F. The weekend is also trending cooler and drier under zonal/northwest flow aloft. There is a chance for showers and thunderstorms on Saturday as a departing low over the Great Lakes region stretches a boundary across much of the southeast, but the column should be dry enough to prohibit coverage and accumulation. Long range guidance offers two primary scenarios for next week: either placement on the eastern periphery of the ridge (promoting northwest flow, cooler temperatures, and increased rain chances) or direct positioning under the ridge, which would renew hot and humid conditions. We will continue to monitor ensemble trends.

DNM

AVIATION

(18Z TAFS) Issued at 1213 PM CDT Wed Aug 19 2026

Outflow from previous convection across northeast Arkansas and the Missouri Bootheel has stalled along the I-40 corridor resulting in variable wind at MEM and northerly flow at JBR and MKL. This feature may act as a focus for additional development as temperatures warm this afternoon, but confidence is not high enough enough to include any mention in the TAF at this time. Confidence is higher in a round of storms overnight as a LLJ develops over the region. The presence of convection will negate the need for LLWS in the TAF. VFR conditions will prevail tomorrow with south to southwest winds generally 3-6 kts.

FIRE WEATHER

Issued at 1213 PM CDT Wed Aug 19 2026

An overall low fire weather risk will hold over the next three days. While temperatures remain hot, light winds and adequate moisture levels will keep critical fire weather conditions well at bay. There is a chance for fog across the northern zones tonight after wetting rainfall, but elsewhere fog potential remains low.

MEG WATCHES/WARNINGS/ADVISORIES

AR...Heat Advisory until 8 PM CDT this evening for ARZ009-018.

Extreme Heat Warning until 8 PM CDT this evening for ARZ026>028- 035-036-048-049-058.

Heat Advisory from 11 AM to 8 PM CDT Thursday for ARZ048-049-058.

MO...Heat Advisory until 8 PM CDT this evening for MOZ113-115.

MS...Heat Advisory until 8 PM CDT this evening for MSZ002>005-009- 013>017-021>024.

Extreme Heat Warning until 8 PM CDT this evening for MSZ001-007- 008-010>012-020.

Heat Advisory from 11 AM to 8 PM CDT Thursday for MSZ007-008- 010>017-020>024.

TN...Heat Advisory until 8 PM CDT this evening for TNZ019-048-050>053- 089>091.

Extreme Heat Warning until 8 PM CDT this evening for TNZ049-088.