textproduct: Memphis

KEY MESSAGES

Issued at 1214 AM CDT Mon Jul 20 2026

- An Extreme Heat Warning has been issued for portions of northwest Mississippi and areas west of the Mississippi River alongside a Heat Advisory across the rest of the Mid-South for Monday and Tuesday.

- Expect afternoon heat indices between 105 - 115 until a cold front reaches the area Wednesday, dropping heat indices below 100 for the remainder of the week.

- Portions of West Tennessee are currently placed in a Marginal (level 1 out of 5) Risk for severe weather on Tuesday. The primary hazards are currently expected to be large hail and damaging winds.

DISCUSSION

(Tonight through next Sunday) Issued at 1118 PM CDT Sun Jul 19 2026

Scattered showers and thunderstorms will continue to produce locally heavy rainfall and flash flooding through early morning Monday. Storms are firing along remnant outflow boundaries from antecedent Sunday afternoon convection. The main focus of thunderstorm generation in the near term is across portions of West Tennessee where a higher coverage of convection has been noted along a multi-boundary collision. Upper winds parallel to this collision corridor, PWATs between 2.0" - 2.3+", and the presence of MUCAPE above 1000 J/kg will continue to provide support for this axis of precipitation to produce very heavy rainfall through the next few hours. Some HRRR guidance has shown some support for this area of showers and storms to last until 2 - 3 a.m. CDT.

Monday will mark yet another day of rising temperatures as ridging amplifies further across the central and eastern CONUS in the wake of an upper trough. Surface temperatures are anticipated to rise into the mid to upper 90s throughout the afternoon amidst a very tropical airmass. Therefore, heat index values are likely to exceed 105 F across the vast majority of the Mid-South. Some areas, especially west of the Mississippi River, could experience heat index values greater than 110 F. Newer guidance this evening has placed these 110 F temperatures more north than before, prompting the expansion of the Extreme Heat Warning farther north into northeastern Arkansas and the Missouri Bootheel. Some showers and storms are possible through the afternoon due some residual troughing from Tropical Depression Two across northeastern Mississippi. However, the coverage of any convection is expected to be low and is not expected to meaningfully cool afternoon temperatures.

Tuesday is more of the same: additional warming under an amplifying ridge. Heat index values will climb in concert with values soaring well above 105 F at most locations in the region. Notably, the eastern extent of 110 F heat indices has shifted east tonight, meaning that confidence is rising in areas just east of the Mississippi River needing an Extreme Heat Warning Tuesday. However, for now we will defer to tomorrow's forecast in lieu of remaining forecast uncertainties in model guidance.

On top of the extreme heat Tuesday, another wave in the broader upper flow will eject southward into the Mid-South throughout the day. By late afternoon, a zone of upper diffluence will overspread the Ohio River Valley and Mid-South ahead of a 50 - 70 knot mid-level jet streak. High surface theta e, responsible for the dangerous heat, will also yield afternoon MLCAPE values above 3500 J/kg over much of the region. Depending on the amount of height falls and/or upper divergence, enough capping may erode to allow for thunderstorm development into the late afternoon and evening. This is most likely to occur on a cold front situated across Missouri and southern Illinois that will travel southward through the day. Timing may preclude a larger risk of severe weather as most guidance prevents the boundary from making it into the region until after sunset and the fact that our area will be under the subsident region within the right exit region of the jet streak. Nonetheless, 30 - 40 knots of shear will be present for storms to work with well into the night with enough of a northerly component to organize a west-to-east line of convection capable of damaging winds and large hail. Therefore, portions of West Tennessee are in a Marginal (level 1/5) Risk for severe weather with the potential for either an expansion or an upgrade to the severe risk in the next 48 hours. Flash flooding is also possible, but storm motions are anticipated to be too fast for a more appreciable threat.

Regardless of the magnitude of convection Tuesday evening, the front will pass into the region by Wednesday morning, making its way through much of the area throughout the day. The passage of the front will bring afternoon temperatures down enough to bring afternoon heat indices below 105 F for many areas. There is still some uncertainty regarding how far south the front makes it, which will be dependent on the coverage of storms Tuesday evening and Wednesday morning. So, a few areas across northern Mississippi could still see Heat Advisory level heat index values (105 - 109 F) and may need another Heat Advisory in the coming forecasts.

The upper pattern takes a notable northwesterly shift after the passage of the front and the initial upper jet streak with the upper ridge retrograding west. Cooler temperatures will prevail through the end of the week with highs in the mid 80s and low 90s Thursday and Wednesday. Upper subsidence and surface dry air advection should be strong enough to keep instability at bay both days, keeping the forecast mostly dry apart from a few afternoon renegade showers. Models indicate that the upper troughing late this week will degrade in amplitude into next weekend with warmer temperatures returning to the forecast, but at this time temperatures do not appear to get as hot as they will be early this week.

AVIATION

(06Z TAFS) Issued at 1214 AM CDT Mon Jul 20 2026

VFR conditions are expected throughout the period. Lingering showers and thunderstorms near MEM and JBR will dissipate within the next few hours. Winds will remain light and variable (6 knots or less) with a westerly to southerly component. MKL has a low-to- moderate probability of MVFR fog overnight. Despite upper-level high pressure limiting convection, a signal for potential activity remains near TUP tomorrow evening.

FIRE WEATHER

Issued at 1118 PM CDT Sun Jul 19 2026

Fire weather concerns are not anticipated as ample moisture remains over the Mid-South and 20ft winds stay below 10 mph.

MEG WATCHES/WARNINGS/ADVISORIES

AR...Extreme Heat Warning from 10 AM this morning to 9 PM CDT Tuesday for ARZ009-018-026>028-035-036-048-049-058.

MO...Extreme Heat Warning from 10 AM this morning to 9 PM CDT Tuesday for MOZ113-115.

MS...Extreme Heat Warning from 10 AM this morning to 9 PM CDT Tuesday for MSZ007-010-011-020.

Heat Advisory from 10 AM this morning to 9 PM CDT Tuesday for MSZ001>006-008-009-012>017-021>024.

TN...Heat Advisory from 10 AM this morning to 9 PM CDT Tuesday for TNZ001>004-019>022-048>055-088>092.