451 FXUS64 KMEG 231749 AFDMEGArea Forecast Discussion National Weather Service Memphis TN 1249 PM CDT Tue Sep 23 2025
...New DISCUSSION, AVIATION, FIRE WEATHER...
.KEY MESSAGES... Updated at 1240 PM CDT Tue Sep 23 2025
- Strong to severe thunderstorms are expected this afternoon and evening, especially across northern and western portions of the Mid-South. Damaging winds and heavy rainfall are the primary threats.
- Another round of strong storms is forecast for Wednesday afternoon, mainly along and east of the Mississippi River, ahead of an approaching cold front.
- A cold front will bring drier and much cooler air for the end of the week, with pleasant conditions expected for the weekend.
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.DISCUSSION... (This afternoon through next Monday) Issued at 1240 PM CDT Tue Sep 23 2025
The latest surface analysis places a couple of weak surface lows over the Plains with one over western Oklahoma and another over northern Kansas. A warm front extends southeast from the Kansas low through southeast Missouri and back into the Mid-South. The front is currently stationary across the Mid-South and located along a WNW to ESE line from Jonesboro, AR to Jackson, TN and back into Huntsville, AL. North of the front, scattered showers and thunderstorms continue to slowly stream across NE Arkansas, the Missouri Bootheel, and NW Tennessee.
Aloft, the pattern remains rather messy, with a deep upper low churning over Colorado with several weak perturbations translating through mainly zonal flow across the Plains into the Lower Mississippi Valley. A couple of MCSs are ongoing across Missouri and have since merged and intensified into one back over extreme SW Missouri. The current weather hazard remains instances of flash flooding as storms continue to train across NE Arkansas, the Missouri Bootheel, and NW Tennessee.
The evolution of the MCS over SW Missouri will dictate our severe weather potential this afternoon and evening. The aforementioned front will wobble north and south across the region and serve as a focal point for renewed convection and potentially heavy rainfall this afternoon and evening. Hi-res guidance continues to show significant run-to-run variability on the evolution of convection across the area this afternoon, likely due to the somewhat diffuse upper level pattern. The highest confidence resides across northern and western portions of the Mid-South, which will see multi-clusters of strong to severe thunderstorms. However, the extent of how far south the storms go still remains uncertain. Nonetheless, areas south of the front have moved into a humid airmass evidenced by lower 70s dewpoints. By this afternoon, instability is forecast to max out around 2500 J/kg of MLCAPE with bulk shear values up to 40 knots by late afternoon, which will support organized multi-clusters. However, mid-level and upper-level lapse rates and low-level helicity remain quite poor. A 2% tornado risk was added to portions of eastern Arkansas, but the threat seems highly conditional and dependent on storms interacting favorably with the frontal boundary. The main threats with any strong to severe storms will be damaging wind gusts and heavy rainfall with a secondary threat of hail and a spinup tornado or two.
Convective activity should weaken late this evening as the mid- level 40 knot speed max lifts north of the area. The latest hi- res guidance is now showing another round of storms moving into the Mid-South after midnight. If this cluster of storms can materialize and hold together, mainly outflow dominant activity will occur due to weak shear and instability in place. The rest of the overnight period will feature mainly scattered non-severe showers and thunderstorms.
Wednesday`s forecast continues to be a challenge. Scattered ongoing thunderstorms and clouds will keep instability shunted across the northern portions of the Mid-South. However, south of I-40 and ahead of a cold front, HREF guidance continues to advertise moderate instability developing by early to mid afternoon across most of north Mississippi and portions of west Tennessee near the TN River. Forecast soundings show only up to 20 knots of deep layer shear, which would limit overall storm organization. Nonetheless, a Marginal Risk (1/5) for strong to severe thunderstorms remains in effect for tomorrow afternoon with damaging winds as the main threat. A higher threat could materialize if deep shear strengthens across the region.
The cold front will sweep through the entire Mid-South by Thursday morning with scattered post-frontal showers during most of the day. Conditions will dry out Friday as the upper-level trough pushes to our east. The weekend will feature dry conditions and highs in the mid 80s and lows in the upper 50s and lower 60s.
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.AVIATION... (18Z TAFS) Issued at 1240 PM CDT Tue Sep 23 2025
The main TAF concern this issuance will be timing and intensity of showers and thunderstorms ahead of a cold front. CAMs continue to struggle on exact timing of convection, therefore, PROB30 and TEMPO groups have been drawn in to best reflect such. As showers and storms move across each terminal, brief drops to MVFR conditions are expected. Otherwise, conditions look to stay largely VFR through this evening. South/southwest winds will prevail sub 10 kts over the next 30 hours or so.
AEH
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.FIRE WEATHER... Issued at 1240 PM CDT Tue Sep 23 2025
Widespread wetting rainfall chances will maximize on Wednesday as a cold front sweeps across the area. Lingering scattered rain will occur on Thursday as an upper level low slowly lifts out of the area. Dry and warm conditions will return this weekend with minimum relative humidity above 40% each day.
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.MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. &&
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PUBLIC FORECAST...AC3 AVIATION...AEH
NWS MEG Office Area Forecast Discussion