textproduct: Jackson

KEY MESSAGES

- Significant severe weather threat including the risk for tornadoes, large hail, and damaging winds remains likely this afternoon into tonight. A strong tornado can't be ruled out.

- Additional rounds of storms could impact the area later in the week.

DISCUSSION

Issued at 220 AM CDT Tue Apr 28 2026

Today into Tonight...

The forecast remains on track and confidence in a widespread, perhaps significant severe weather episode is growing. A composite outflow/cold frontal boundary is now readily apparent as ongoing convective to our north is generating a well-defined cold pool. This early activity will likely meander south into our area by around dawn before becoming stalled and more diffuse. This will be a primary focal point for severe storm upscale growth and organization later today and could aid storm development by providing a narrow zone of enhanced low level helicity and locally higher boundary instability associated with moisture pooling.

The general synoptic pattern features split flow aloft which favors effective synoptic scale divergence. At the same time, a stout, embedded shortwave is now moving across TX/OK and will progress across the Texarkana region by midday. This will likely trigger widespread thunderstorm growth progressively eastward as it encounters a weakly capped, very moist boundary layer into the ArkLaMiss.

Tornado Threat:

Low level shear will remain modest (0-1 KM storm relative helicity (SRH) < 150 M^2/S^2) in general, though organizing clusters of storms into one or more mesoscale convective systems/vortices (MCS/MCV) could locally back surface winds in their proximity. Should this happen, both discrete storms directly ahead of the complex within the environment of improved low level jet (LLJ) velocities as well as any circulations that are embedded within surging line segments could produce tornadoes.

Notably, guidance consensus shows that the nose of the impinging mid- level jet around 850-500 mb/2-4km AGL will be very sharply defined as the shortwave energy/higher velocities arrive around 21-23Z. At 700 mb for example, velocities could differ across this boundary from <25 kt flow to the east to >40 kt flow within the jet axis to the west over a span of < 20 miles.

Storms will likely erupt along this boundary and the most probable scenario is for storm activity and this demarcation line of much higher flow to move eastward in tandem with individual storm elements being restrained somewhat by a tendency to outrun the better shear environment. This suggests that storm clusters will grow quickly upscale and result in primarily a damaging wind threat.

If, however, any discrete storms manage to reside for an hour or two within the increasing flow (which would likely require deviant motion closer to the Bunker's-right estimation of <30 kt forward motion), there does appear to be a window for such a storm to produce significant severe weather including damaging winds up to 70 mph, hail as large as golf balls, and tornadoes. While this threat is conditional, a strong tornado (EF-2+) can not be totally ruled out at this time. These higher-end threats will be most likely within the "Enhanced" (3/5) risk areas generally defined as areas north of the Highway 84 corridor.

The arrival time of the better deep layer shear is of high confidence (21Z and beyond) which suggests the tornado threat will be maximized by a scenario that features delayed onset of widespread convection. In short: the longer it takes for storms to get going this afternoon, the worse the outcome could be in terms of tornado risk.

Large Hail and Damaging Wind Threat:

The parameter space for large hail and damaging winds is more clearly defined. Mixed layer convective available potential energy (ML-CAPE) will likely exceed 2,000 J/KG for much of the area with locally higher values to 2,500 J/KG where moisture pooling is favored in the vicinity of the surface boundary. Deep layer shear will be adequate for all severe modes as 50-55 kts of 0-6 km bulk shear likely becomes realized by this evening into the overnight period. Given the surface boundary orientation and supported by increasing model consensus, damaging winds are likely and winds gusts as high as 70 mph are possible. Lapse rates aloft won't be particularly impressive and storm mode favoring upscale growth puts further question marks on hail potential, but particularly in "younger" cells that may develop ahead of potential MCS/organized clusters, large hail to golf ball size (1.75") will be possible.

Flash Flood Threat:

With precipitable water values (PWATs) above 1.8", storm motions not particularly fast for our area this time of year (generally less than 40 kt forward motion), and the tendency for storms to move over the same areas, localized flash flooding appears increasingly possible. A "Limited" threat for heavy rainfall continues to be advertised for portions of Southeast Arkansas and North Mississippi through tonight. Most areas along and north of the I-20 corridor will see rainfall totals of 1 to 2 inches with amounts tapering off dramatically with southern extent. Localized areas of 3 to 6 inches where thunderstorms train could lead to some localized flash flooding, particularly in low lying and urban areas.

Wednesday Through Early Next Week..

Following storms Tuesday, the boundary will likely sink toward the Gulf Coast during the day Wednesday. This could allow for an additional round of scattered storms during the peak heating Wednesday afternoon of which a few could be marginally severe with attendant hail/wind risks. By Thursday, lowered humidity and an at least temporary end to the near daily strong/severe storm risk is likely.

By late Friday or early Saturday, a potent southern stream shortwave will likely bring our next shot at strong to potentially severe storms. The major caveat with this activity will be the surface boundary and how far inland the developing surface cyclone can force it. With little space between the departing long wave trough and the incoming shortwave, the warm front will be facing a tug-of-war scenario as continental dry air and a surface high not far away, perhaps as near as northern Georgia, attempting to remain entrenched squares off against the southerly mass recovery attempts of the incoming surface cyclone/frontal wave. The demarcation between noisy and wet weather versus strong to severe storms will likely be defined by this progress an guidance differs greatly on how that may play out. For now, the most likely scenario would be for some stronger storm risk across our southernmost areas. This situation should be monitored carefully particularly for folks along or south of the I-20 corridor.

Looking ahead into early next week, guidance is starting to show a 1020mb sfc high over the Southern Plains shifting towards our forecast area. This will allow for quiet weather conditions to persist over the region with daytime highs peaking in the upper 70s.

Taking a perhaps daring glance into the forecast beyond day 7 suggests more active weather is likely with attendant risks for thunderstorms, perhaps severe. Attempting to declare any specificity would be foolhardy, but it does seem like we will be making some dent in the local drought conditions over the next couple of weeks. /86/CR/

AVIATION

(06Z TAFS) Issued at 1246 AM CDT Tue Apr 28 2026

VFR conditions prevail in most areas, but MVFR ceilings were beginning to spread into south MS early this morning. A bout of low stratus, reducing ceilings to MVFR and locally IFR, is expected to develop overnight. Over the southern half of the area, VFR conditions will likely return by mid to late morning, but MVFR conditions may persist in some areas farther north. During the day Tuesday, multiple rounds of TS and SHRA are expected to move across the area, and some storms could produce wind gusts over 50 kt and large hail with tornadoes also possible. Visibility may be reduced in periods of +RA. Storms will are expected to end Tuesday evening. /DL/

PRELIMINARY POINT TEMPS/POPS

Jackson 87 66 83 61 / 60 60 60 70 Meridian 86 65 85 59 / 70 60 60 70 Vicksburg 88 67 82 61 / 60 60 60 70 Hattiesburg 88 67 88 64 / 20 30 40 70 Natchez 90 69 86 63 / 40 30 60 70 Greenville 84 68 77 57 / 90 90 40 50 Greenwood 84 66 80 57 / 90 90 50 50

JAN WATCHES/WARNINGS/ADVISORIES

MS...None. LA...None. AR...None.