textproduct: Jackson

KEY MESSAGES

- Significant flash flooding threat continues with conditions worsening late tonight into Thursday.

- 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 Thursday and Friday.

MESOSCALE UPDATE

Issued at 1038 AM CDT Wed Jun 17 2026

Per the National Hurricane Center Tropical Storm Arthur has formed this morning near the middle Texas coast. TS Arthur is forecast to move northeast along the Texas coast today and move inland over southwestern Louisiana by tonight. TS Arthur will then weaken as it continues moving inland and to the northeast reaching our northeast Louisiana Parishes by Thursday morning. The main threats to our CWA from TS Arthur remain unchanged and will remain the flooding rain threat especially across our southern zones. There will also be the potential for isolated severe storms capable of brief tornadoes and damaging wind gusts Thursday and Friday. As for the rest of today, we still have a moist airmass across the CWA that will lead to shower and thunderstorm development through this afternoon into this evening. The rain chances and associated cloud cover will hold temperatures below normal again central and south. /22/

DISCUSSION

Issued at 116 AM CDT Wed Jun 17 2026

Today...

Reinforced shortwave ridging will tend to suppress convection/rainfall today, which is certainly good news for those who received the greatest amounts yesterday. During this break however, there may still be ongoing hydrologic response to yesterday's rainfall, so creeks and smaller rivers may remain elevated. We still anticipate potential for significant flash flooding associated with a tropical low expected to pass over the area tomorrow. Note, this will be additional rainfall to what has already fallen this week so far. Minor adjustments were made this forecast update to account for the southward trend. As such, "significant" flash flood threat was trimmed from the northwest and some of the northeast, and expanded into the east and southeast. Totals within the "significant" were also adjusted slightly upward to reflect latest guidance.

Through mid next week...

The tropical Gulf low will be the focus for the next round of heavy rainfall tomorrow for our area. This feature will carry with it a very moist airmass possibly in excess of 2.5 inch PWAT. Given antecedent conditions, this additional round will exacerbate flash flood threat, especially for areas that received great amounts yesterday. While TC development probabilities continue to be 60%, the primary threat of flash flooding remains unchanged, therefore hazard messaging remains consistent.

There will also be a low end risk for severe associated with the tropical low. Despite moist adiabatic lapse rates, low level shear may be enhanced by the low. Along with significant deep moisture, embedded low topped supercells cannot be ruled out, though the risk remains low. The primary severe concerns would likely be wind and perhaps a weak tornado within the tropical regime.

There is renewed concern for flash flood threat to continue into Friday as a boundary in the wake of the tropical low stalls somewhere in the vicinity of I-20. The placement of this feature is uncertain at this time, but more guidance seems to be picking up on it. We will continue to watch closely and provide future updates.

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 may be on the way. /SAS/

AVIATION

(12Z TAFS) Issued at 643 AM CDT Wed Jun 17 2026

Ceiling/vsby forecasts continue to be complex through early this morning, but fog has diminished as southerly gradient winds begin to pick up. Increased mixing after sunrise will help to quickly improve ceilings to MVFR/VFR by late morning. Otherwise, we'll be in a relative lull in terms of rain coverage ahead of the approaching low center before we see a dramatic increase in rainfall late tonight that should coincide with reduced ceilings. /EC/

PRELIMINARY POINT TEMPS/POPS

Jackson 87 74 86 74 / 40 60 90 60 Meridian 87 73 84 73 / 50 70 90 70 Vicksburg 88 74 88 75 / 40 50 70 50 Hattiesburg 86 74 85 76 / 50 80 90 60 Natchez 87 74 88 76 / 50 70 80 40 Greenville 90 75 90 74 / 20 20 50 70 Greenwood 91 75 89 74 / 20 30 60 70

JAN WATCHES/WARNINGS/ADVISORIES

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

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

AR...None.