textproduct: Memphis

KEY MESSAGES

Issued at 1208 PM CDT Thu Aug 20 2026

- Isolated to scattered strong to severe thunderstorms could occur this afternoon and evening along and south of I-40. Damaging wind gusts are the primary threat.

- A Heat Advisory remains in effect until 8 PM CDT today for eastern Arkansas and north Mississippi, with heat index values peaking between 105 and 109 degrees.

- Friday is the final day of oppressive heat and humidity for the Delta region, with a transition to drier and cooler conditions expected this weekend.

DISCUSSION

(This evening through next Wednesday) Issued at 1208 PM CDT Thu Aug 20 2026

A few showers and thunderstorms are ongoing across West Tennessee as of 11 AM. These are being initiated as a frontal boundary remains nearly stationary along the I-40 corridor. This front will begin to sink south in the coming hours. This will provide lift to generate isolated to scattered thunderstorm development in the wake of the front. Temperatures across north Mississippi are projected to climb into the mid to upper 90s which will allow SBCAPE to surge between 2500-3000 J/kg. Effective shear is anticipated to remain below 30 kts which will support a single/multi-cell mode. Deterministic soundings do favor the inverted v, increasing confidence in a damaging wind/wet microburst threat. Due to surface temperatures, the hail threat will most likely be sub-severe but the potential for quarter sized hail cannot be ruled out. The RRFS is the most aggressive in storms this afternoon and favors 3 PM to 11 PM as an initiation window. Aside from severe weather, there is a heat advisory in effect through 8 PM for portions of eastern Arkansas and north Mississippi.

It will take additional time for the continental polar air mass to sink all the way south, thus one more heat advisory has been issued for the Delta region for Friday heat index values peaking around 109. Elsewhere, the cooler and drier air will filter in and take hold through the weekend. An upper level disturbance, embedded in northwest flow aloft, may bring a few showers across the area on Saturday afternoon. The Canadian and NAM models are very aggressive with the coverage, which likely inflates NBM PoPs. NBM soundings show a rather dry air column, and QPF values are less than a quarter of an inch. Would expect these two models to fall more in line with the Euro and be a better fit for the current QPF forecast.

For the long term, the GFS and Euro have fallen in line and keep an upper level ridge centered over the central US. This will keep the Mid-South under northwest flow and bring increased rain chances through the work week. Increased rain chances however does normally favor a cooler temperature regime. The LREF and its ensemble members currently have nil probabilities of severe weather ingredients through this pattern. Despite the increased rain chances, probabilities of accumulating 1" or more of rainfall from the LREF ensemble members is low (10-30%). One ensemble member, (GEPS) is highlighting a 40-50% chance of accumulating 1" or more over the Missouri Bootheel by next Thursday. While the pattern change brings cooler temperatures, confidence in significant drought relief remains low given the lack of substantial QPF signal.

DNM

AVIATION

(18Z TAFS) Issued at 1208 PM CDT Thu Aug 20 2026

VFR conditions are expected to prevail at JBR, MEM, and MKL through tomorrow. Convection should be confined to north Mississippi this afternoon along and south of a stalled cold front. As a result, all mentions of convection were omitted from the 18Z update for these locations. A PROB30 group for thunderstorms has been included for TUP.

FIRE WEATHER

Issued at 1208 PM CDT Thu Aug 20 2026

A low fire weather risk will hold across the region over the next three days. While summer heat remains strong across the Mid- South, adequate moisture levels and exceptionally light surface winds will prevent critical fire weather conditions from developing. Rainfall from this morning will result in the development of patchy to locally dense fog late tonight for areas east of the Mississippi river.

MEG WATCHES/WARNINGS/ADVISORIES

AR...Heat Advisory until 8 PM CDT this evening for ARZ048-049-058.

Heat Advisory from 11 AM to 8 PM CDT Friday for ARZ049-058.

MO...None. MS...Heat Advisory until 8 PM CDT this evening for MSZ007-008-010>017- 020>024.

Heat Advisory from 11 AM to 8 PM CDT Friday for MSZ007-010-011- 020.

TN...None.