textproduct: Memphis

KEY MESSAGES

Updated at 354 AM CDT Wed Apr 2 2025

-Severe weather and very heavy rainfall are expected this afternoon through Saturday. -Five day total rainfall amounts are in the 10 to 15 inch range along and north of I-40. This is not your average flood risk. Generational flooding with devastating impacts is possible.

-A High Risk of severe weather today, a Slight Risk is in effect Thursday,Friday and Saturday.

-A Moderate Risk of excessive rainfall is in effect today, Friday and Saturday with a High Risk on Thursday.

DISCUSSION

(Today through Tuesday) Issued at 354 AM CDT Wed Apr 2 2025

A dangerous weather pattern will unravel this afternoon as an upper level low and attendant cold front will impinge on the area. As the system inches closer, the pressure gradient will tighten and bring strong sustained and gusty wind conditions. A Wind Advisory will go into effect at 7 AM this morning due to these conditions. The highest winds will be found across northeast Arkansas, the Missouri Bootheel, and northwest Tennessee with gusts up to 50 mph possible. Elsewhere, gusts around 40 mph and sustained winds between 20-30 mph are expected.

Surface analysis as of 3 AM shows a warm front lifting north across the Memphis metro. Surface observations behind the boundary show dewpoints entering the 60s. This moisture will provide ample instability combined with lift from the approaching cold front and a 70 kt LLJ; a High Risk for severe weather is in store for portions of the Mid-South today. The upgrade in risk is tornado driven as SRH values exceed 200 m2/s2 with curved and elongated hodographs. The CAMs have also been more in favor of discrete cell development, and given this prime environment, these cells could easily turn supercellular and produce strong tornadoes. Discrete cell development will be approaching from the west as early as 3 PM this afternoon.

Strong tornadoes are not the only concern, lapse rates are between 7-8C/km with almost 3,000 MUCAPE to work with, significant hail is not out of the question; especially in any supercells. The discrete cells eventually will congeal into a line as the cold frontal boundary is anticipated to stall practically along the I-4O corridor late tonight which will shift to a damaging wind threat of 70+ mph gusts. Once the storm mode is more linear, embedded supercells within the line could still produce a tornado. The most likely timing for the severe weather is 3 PM- 12 AM as the loss of daytime heating and rain cooled surfaces should help stabilize the environment. It is so important to have multiple ways to receive warnings especially as some of these tornadoes could be strong and long tracked. All hazards could occur after sunset, which is the most deadly time.

As mentioned above, the stalled frontal boundary will linger with at least slight chances of severe weather through Saturday. Instability to the south of the front is still favorable of a strong to severe thunderstorm. As this front remains parked, it will provide enough lift and bursts of energy to need to be monitored for a few storms with all hazards at play. This pattern will continue until the front clears the area. Saturday, the severe weather threat could increase slightly across north Mississippi as the front begins to move over a not as saturated area.

While we continue to monitor the severe weather potential, a historical rainfall event will commence. Generational flash, river, and areal flooding are all possible. Maxed out precipitable water values for four convective days, training storms extremely likely, and any convective development increasing localized amounts has QPF values forecast to be in the 10-15 inch range. The area likely to see such high amounts will be along and north of I-40. Considerable flash flooding, especially in urbanized areas, is expected. Never drive through flooded waters, and flooded roadways are significantly more difficult to see at night. The axis of heavy rainfall could still very easily shift so be sure to continue to monitor the forecast.

While our current forecast could break several rainfall records across the area, it is a bit more optimistic for it to be more spread out over four days, however, the culmination will put a strain on the ground's ability to absorb. At some point, soils will become supersaturated and leave no option but to reject all the additional rain as runoff. Flash flooding will emerge as a primary concern with this extremely active pattern. In addition, all of this rainfall will make tree limbs very weak and easily breakable. It is best to not only prepare for flooding, but power outages as well. Moderate Risks and a High Risk of excessive rainfall are in effect for portions of the Mid-South each day through the event.

Once the front is forced out of the area by a reinforcing cold front, dry and cooler conditions return Monday morning. Until then, stay safe.

DNM

AVIATION

(06Z TAFS) Issued at 1132 PM CDT Tue Apr 1 2025

Ceilings expected to deteriorate to MVFR conditions overnight then gradually improving back to VFR towards late Wednesday morning. LLWS to continue into Wednesday morning. Latest high resolution guidance suggests best potential for TS will be late afternoon at JBR, Wednesday evening at MEM/MKL, and perhaps for a short period at TUP Wednesday evening. The best coverage of TS appears to be along a MEM/MKL corridor Wednesday night. Confidence is lower on coverage after 6Z at MEM and went with PROB30s to handle nearby convection which may train near MEM and continue into Thursday morning.

MEG WATCHES/WARNINGS/ADVISORIES

AR...Wind Advisory from 7 AM this morning to midnight CDT tonight for ARZ009-018-026>028-035-036-048-049-058.

Flood Watch from 1 PM CDT this afternoon through Sunday morning for ARZ009-018-026>028-035-036-048-049-058.

MO...Wind Advisory from 7 AM this morning to midnight CDT tonight for MOZ113-115.

Flood Watch from 1 PM CDT this afternoon through Sunday morning for MOZ113-115.

MS...Wind Advisory from 7 AM this morning to midnight CDT tonight for MSZ001>017-020>024.

Flood Watch from 1 PM CDT this afternoon through Sunday morning for MSZ001>005-007-008-010>014-020.

Flood Watch from late Friday night through Sunday afternoon for MSZ006-009-015>017-021>024.

TN...Wind Advisory from 7 AM this morning to midnight CDT tonight for TNZ001>004-019>022-048>055-088>092.

Flood Watch from 1 PM CDT this afternoon through Sunday morning for TNZ001>004-019>022-048>055-088>092.