Vermilion Water Watch: Stable Salinity Before Wednesday East Wind

Updated: Tuesday, September 15, 2026, at 8:30 a.m. CDT

Publishing status: Review needed. Official observations are current enough for a same-day report. Human review remains appropriate because NWS expects heat indices of 103-107F, isolated afternoon storms with wet microburst potential, and a Wednesday east-wind increase that may produce choppy to rough bay water.

Fishing-impact summary

Atchafalaya River at Simmesport measured 100,000 ft3/s at 8:30 a.m., with a preceding-day range of 100,000-105,000 ft3/s. The upstream river signal is lower than Monday's report and does not indicate a renewed freshwater pulse.

Cypremort Point salinity measured 17 ppt at 8:00 a.m. and ranged from 16 to 17 ppt during the preceding day. That is stable, moderately brackish water at the station, but it does not define every reef, pass, canal or Marsh Island drain.

Morgan City turbidity measured 13.2 FNU at 8:00 a.m. and ranged from 10.2 to 27.4 FNU during the preceding day. This is a cleaner lower-river signal than Monday's brief 50.0-FNU spike, but Morgan City does not directly measure Vermilion Bay clarity.

NOAA predicted a high at 6:28 a.m. at 1.60 feet and a low at 3:16 p.m. at 0.37 feet. That approximately 1.23-foot daytime fall should provide useful outgoing current around Marsh Island drains, oyster edges, canal mouths and Southwest Pass.

What changed since the prior report

Simmesport declined from 107,000 ft3/s Monday morning to 100,000 ft3/s at 8:30 a.m. Tuesday.
Wax Lake Outlet measured 54,100 ft3/s at 7:45 a.m.; its preceding-day range was 32,500-71,400 ft3/s because tide and coastal backwater strongly influence this outlet.
Morgan City measured 59,100 ft3/s at 8:00 a.m. and remained fresh at 0.2 ppt.
Morgan City turbidity improved to 13.2 FNU after ranging from 10.2 to 27.4 FNU during the preceding day.
Morgan City dissolved oxygen measured 7.9 mg/L at 8:30 a.m., with a 6.4-7.9 mg/L preceding-day range.
Cypremort Point salinity stayed at 17 ppt, with a 16-17 ppt preceding-day range.
Cypremort Point wind measured 5.8 mph from 63 degrees at 8:00 a.m.
NWS continues to call for smooth bay water today, then choppy bay water Wednesday and rough bay water Wednesday night as east wind increases.

Measured conditions

Measurements are provisional USGS observations.

Atchafalaya River at Simmesport: 100,000 ft3/s and 6.41-foot gage height at 8:30 a.m. Discharge ranged from 100,000 to 105,000 ft3/s during the preceding day.
Wax Lake Outlet at Calumet: 54,100 ft3/s, 2.54-foot gage height and 1.28-ft/s velocity at 7:45 a.m. Tide and coastal backwater continue to cause large short-term variation.
Lower Atchafalaya River at Morgan City: 59,100 ft3/s and 2.60-foot gage height at 8:00 a.m. Water temperature was 27.6C/81.7F, salinity 0.2 ppt, turbidity 13.2 FNU and dissolved oxygen 7.9 mg/L.
Vermilion Bay near Cypremort Point: Wind measured 5.8 mph from 63 degrees at 8:00 a.m. Water temperature was 31.2C/88.2F, salinity was 17 ppt and gage height was 2.31 feet. Salinity ranged from 16 to 17 ppt during the preceding day.

Official forecast

The NWS Lake Charles Area Forecast Discussion issued at 12:40 a.m. says high pressure centered over the northern Gulf Coast will limit daily thunderstorm potential to roughly 20-30% this week. Tropical moisture remains present, and isolated convection is expected during the afternoon.

NWS highlights wet microburst potential with stronger storms because modeled downdraft energy is elevated. Outside thunderstorms, high temperatures should reach the mid-90s, with heat indices in the 103-107F range. Heat advisory criteria are not met in the fetched discussion, but heat safety precautions are still urged.

For Vermilion and West Cote Blanche Bays, the 3:09 a.m. coastal-waters forecast calls for:

Tuesday: North wind around 5 knots, becoming northeast late this morning, then south around 5 knots this afternoon. Bay waters smooth, with a slight late shower or thunderstorm chance.
Tuesday night: South wind around 5 knots becoming east after midnight. Bay waters smooth, with a slight evening shower or thunderstorm chance.
Wednesday: East wind 10-15 knots. Bay waters choppy, with afternoon showers and thunderstorms possible.
Wednesday night: East wind 15-20 knots. Bay waters rough, with evening showers and thunderstorms possible.
Thursday: East wind 10-15 knots with choppy bay water.

No marine watch, warning or advisory was listed in the fetched forecast, but the marine discussion says Small Craft Advisories will likely become necessary for Wednesday into Thursday over portions of the coastal waters. Winds and waves will be higher in and near thunderstorms.

Tides and storm-driven movement

NOAA astronomical predictions for Cypremort Point, relative to MLLW, are:

Tuesday low: 3:10 a.m. at 1.52 feet
Tuesday high: 6:28 a.m. at 1.60 feet
Tuesday low: 3:16 p.m. at 0.37 feet
Wednesday high: 1:40 a.m. at 1.71 feet
Wednesday low: 4:05 p.m. at 0.39 feet

The primary daytime move is the approximately 1.23-foot fall from the 6:28 a.m. high to the 3:16 p.m. low. Water then rises strongly into Wednesday's early-morning high. The USGS Cypremort Point gage uses a different datum from NOAA MLLW and should not be directly compared with these predicted tide heights.

Likely water movement - fishing inference

This section is a fishing inference based on measured observations, astronomical tides and official forecasts rather than direct bay-wide current observations.

Today's long fall should pull marsh water through drains, canal mouths, protected cuts and Southwest Pass through much of the day. The most dependable current should be near constrictions, oyster edges and drain-to-bay transitions.

Cleaner, saltier water remains more likely around Southwest Pass, outer Marsh Island and deeper reef edges than around eastern Marsh Island, rain-fed drains and Atchafalaya-facing water. That distribution must be verified locally because the available stations do not measure every fishing area.

By Wednesday, stronger east wind may push against exposed shorelines, slow or complicate normal drainage, muddy shallow banks and make open-bay or Southwest Pass crossings less comfortable.

Water clarity and salinity outlook

Morgan City turbidity at 13.2 FNU supports an improved lower-river clarity signal, and the preceding-day maximum of 27.4 FNU is less concerning than Monday's isolated 50.0-FNU spike. Still, Morgan City is not a Vermilion Bay clarity station.

Cypremort Point has no turbidity sensor. Its 16-17 ppt salinity range is stable enough for Redfish, Specks and Black Drum, but it is one station. Local freshwater, rain runoff, vessel traffic and wind exposure can change conditions quickly over short distances.

Today is the better near-term window for smooth-water scouting. Wednesday's east wind may reduce clarity along exposed banks, shallow reefs and open bay edges.

NASA Worldview

Same-day September 15 NASA Worldview/GIBS true-color imagery was not expected to be available for an early report because daylight overpass and near-real-time processing occur later. The newest practical imagery context should use the latest available prior-day regional scene and clearly state its date.

NASA Worldview regional view for September 14, 2026

Satellite imagery is contextual only. It does not prove salinity, dissolved oxygen, harmful algae, general water quality or fish movement. Clouds, haze, sediment, sun glint, swath boundaries, cloud shadows and shallow-bottom reflectance can all affect apparent water color. No precise bay-wide clarity conclusion is made from satellite color alone.

Best areas

Specks: Southwest Pass, outer or southern Marsh Island and deeper reef edges after water color, bait and salinity are confirmed.
Redfish and Black Drum: Protected Marsh Island drains, points and oyster edges carrying manageable outgoing current.
Flounder: Drain-to-bay transitions where falling marsh water meets clearer bay water.
Tripletail and Cobia: Nearshore structure or floating cover during today's light-wind periods, provided visibility is adequate and storms remain distant.

Species-specific implications

Redfish: Stable 16-17 ppt salinity and a long fall favor drains, oyster edges and points with visible bait.
Specks: Salinity is workable, but clarity and bait remain the deciding factors. Start near Southwest Pass, outer Marsh Island and deeper reef edges.
Tripletail: Smooth bay and light wind may support sight fishing where visibility is adequate, but haze, glare and isolated storms can limit the window.
Cobia: Today offers a better access window than Wednesday and Thursday, when east wind increases.
Black Drum: Moderately brackish water and oyster edges remain suitable, especially near stained-to-clean transitions.
Flounder: The daytime fall can improve ambush opportunities at drains and pass edges. Avoid constrictions with excessive current or debris.

Recommended approach

Use the long falling tide to fish protected Marsh Island drains, points and oyster edges where current is visible but manageable. Check Southwest Pass and outer Marsh Island for cleaner Speck water only after confirming water color and bait.

Favor today for exposed crossings or nearshore searches. Recheck the marine forecast before Wednesday or Thursday trips because east wind, choppy-to-rough bay water and possible advisory headlines may materially change safe access.

Expected timing and duration

The main outgoing window runs from shortly after the 6:28 a.m. high through the 3:16 p.m. low. Water rises strongly tonight toward the 1:40 a.m. Wednesday high, followed by another long daytime fall Wednesday, but wind conditions should be less favorable by then.

Confidence, uncertainty and localized conditions

Confidence is high in the official USGS observations, NOAA tide predictions and NWS marine forecast. Confidence is moderate in the falling-tide fishing inference. Confidence is lower in bay-wide clarity because Cypremort Point has no turbidity sensor and Morgan City is not a direct Vermilion Bay clarity station.

Cypremort Point and Morgan City are individual stations. Cypremort Point does not define salinity across every reef, shoreline or Marsh Island drain, and Morgan City does not establish conditions around Southwest Pass. Local rain, vessel traffic, sediment resuspension and wind exposure can produce different conditions over short distances.

Harmful algae and dissolved oxygen

LDEQ harmful-algal-bloom guidance remains the standing public reference for visible blue-green algae. No fetched source confirmed a new Vermilion Bay-specific HAB notice in this run. Morgan City dissolved oxygen measured 7.9 mg/L at 8:30 a.m., which is not an oxygen-collapse signal at that station, but it does not establish conditions inside shallow, stagnant or warm canals.

Safety notes

No marine advisory is active for Vermilion and West Cote Blanche Bays in the fetched forecast, but heat indices may reach 103-107F and isolated storms can produce lightning, wet microbursts and locally higher wind and waves. Wednesday's east wind is the bigger planning change: 10-15 knots and choppy bay water Wednesday, then 15-20 knots and rough bay water Wednesday night.

Vermilion Bay grows memories with shoulders.