textproduct: Jackson

KEY MESSAGES

- Significant flash flooding threat continues with conditions worsening this morning into the afternoon.

- Rainfall will continue on Friday. Flooding impacts may linger. Rainfall does not end quickly, but rather gradually tapers over the course of several days.

- Isolated severe storms are possible over the area today and again on Friday.

MESOSCALE UPDATE

Issued at 941 AM CDT Thu Jun 18 2026

Mid morning satellite imagery/RAP analysis showed the circulation around the remnant of Tropical Storm Arthur centered over our CWA. Local radars suggested the center of circulation over our northeast zones. The local radars were lit up with storms over the southeast two thirds of our CWA with the heaviest rainfall generally along and southeast of the Natchez Trace. A Tornado Watch remains in effect for Marion, Lamar, Forest and Jones counties until 5PM. Most of the tornadic activity has occurred southeast of Forest county but the potential in our southeast will remain into the afternoon. Flooding rain remains the main threat today and rivers are on the rise as well. /22/

DISCUSSION

Issued at 1211 AM CDT Thu Jun 18 2026

Today...

The remnant tropical low feature is expected to bring a significant flash flood threat to southeastern portions of the area today as soil moisture remains high and antecedent rainfall has made this area vulnerable. As much as 4-7 inches of rain could fall, locally higher upwards of 10-12 inches in some guidance amid the tropical airmass, support of efficient rainfall rates. 00z regional soundings show a 2.1 to 2.2 inch PWAT airmass, which is similar to Tuesday. Considering this, we know that 8 inch amounts were observed or estimated, so it is likely this airmass would still be capable of those amounts. Further, probabilities for 8 inches have increased to 20% in spots on CAM guidance.

Additionally, there will be a marginal severe threat with this system, primarily for damaging wind gusts and brief, weak tornadoes. Tropical remnants can enhance low level shear, and back surface winds. Considering this along with a very moist BL, brief tornadoes are possible, particularly this morning associated with core convection.

Rainfall does continue even after the remnant low passes with a trailing boundary. Placement of this potential is still uncertain, however a lot CAM guidance has shifted this south, perhaps even south of our area (Wilkinson, Amite, Pike, Walthall). But, should this materialize, it would exacerbate flood risk and any ongoing flooding as any additional rainfall would push things over the edge. Furthermore, this would be a training convection scenario that could add to totals. It is possible that convection reinvigorates along this boundary Friday, but again, it is uncertain.

Through mid next week...

The boundary begins to make headway into the area by the weekend and likely washes out this weekend. Airmass modification is likely slim, but PWAT, while still supportive of additional rainfall, will be more seasonal (1.5-1.7). This should provide some "break" from the onslaught of moisture, with coverage overall more scattered this weekend. Additional rainfall amounts this weekend generally look to be in the 1 to 2 inch range. Southwesterly flow will continue to reinforce rain chances through the remainder of the period, but increased westerly/northwesterly flow by the middle next week may mean that relief from heavy rainfall may be on the way.

Towards the end of the period, there is potential to transition towards a NW flow regime as a ridge strengthens over the SW CONUS. Right now in the guidance it looks like there is potential for a stalled boundary to be in place, while multiple shortwaves ride the ridge. All the while, low level flow will likely remain southwesterly as we remain under the western flank of the low level ridge. This could set up the area for rounds of severe weather, likely MCS scenario. Of course, more details will be provided as they become available. /SAS/

AVIATION

(12Z TAFS) Issued at 713 AM CDT Thu Jun 18 2026

Lowering ceilings and increasing chances for RA will continue as the remnants of Tropical Storm Arthur move across the forecast area. Areas of rain will be accompanied by reduced visibility and potentially gusty winds. Some improvements in ceilings and/or visibility is likely after 18/22-23Z, with decreased rain coverage into the evening hours. Additional lowered ceilings and/or visibility will develop again overnight, with increased rain chances as well through the end of the TAF period. /NF/DC/

PRELIMINARY POINT TEMPS/POPS

Jackson 84 74 87 73 / 100 60 80 70 Meridian 81 73 86 72 / 100 80 80 50 Vicksburg 86 75 88 74 / 90 60 80 70 Hattiesburg 83 76 90 75 / 100 70 60 60 Natchez 86 76 91 75 / 90 40 50 60 Greenville 88 74 87 73 / 60 70 80 60 Greenwood 85 74 88 73 / 80 80 70 50

JAN WATCHES/WARNINGS/ADVISORIES

MS...Flood Watch through Friday evening for MSZ040>066-072>074.

LA...Flood Watch through Friday evening for LAZ009-015-016-023>026.

AR...None.