Marine Weather and Tide Forecast for Biloxi, MS

SHORT TERM
(This evening through Friday night)
Issued at 1225 PM CDT Thu Oct 23 2025

Upper low centered over Quebec this morning with ridging moving into the Plains States. A southern stream trough was over Utah and Arizona, with a northern stream shortwave off the British Columbia coast. At the surface, high pressure was centered over Alabama and Georgia. Weak low pressure was over the Desert Southwest, with a much deeper low over the Gulf of Alaska. Just some thin cirrus moving across the area this morning, with temperatures in the 70s to around 80 at midday.

Shortwave ridging will move across the northern Gulf Coast over the next 36 hours as the southern stream shortwave moves into west Texas by Saturday morning. Surface winds will become southeasterly Friday and Friday night, with moisture levels only slowly responding.
Precipitable water values will still only be near the 25th percentile at sunset Friday, but closer to the 75th percentile by sunrise Saturday. Don't expect much in the way of significant cloud cover until perhaps after midnight Friday night, and even then only in the western half of the area.

Relative humidity values will remain near critical levels today across the northern half of the area (25-35 percent), but winds should remain below 10 mph in most areas. Moisture levels should begin to recover tomorrow afternoon, but still could be a few locations east of Interstate 55 that could approach critical levels with winds 10-15 mph.

Guidance fairly consistent on overnight lows tonight and highs tomorrow. If there was going to be an adjustment to temperatures, it wouldn't be much more than a degree or two, probably upward. Chasing a 1 degree change doesn't qualify as a target of opportunity though.

Coastal flooding potential still looks borderline for Friday night's high tide cycle on southeast facing coastlines, with more of a threat Saturday night. Assuming nothing changes in the next few hours as far as guidance goes, will hold off on any Coastal Flood Advisory issuance for Friday night with this package. Evening and/or mid shift tonight can revisit whether we'll meet criteria.

LONG TERM
(Saturday through Wednesday night)
Issued at 1225 PM CDT Thu Oct 23 2025

Main concerns during the long term portion of the forecast will be the potential for heavy rainfall and minor coastal flooding with a storm system expected to impact the area from late Saturday through Sunday. Expect that we will probably need a Coastal Flood Advisory for east/southeast facing shorelines for high tide cycle Saturday night, which would probably get issued late tonight or on Friday.

The southern stream upper trough that is expected to be over west Texas Saturday morning will have a couple spokes of energy moving through the base of the trough. The first will be approaching the Sabine River Saturday morning, with the second over New Mexico.
Precipitable water levels near the 75th percentile (1.6 inches) will overspread the entire area Saturday afternoon, with the potential for at least scattered convection prior to sunset, primarily west of Interstate 55. That shortwave energy should be east of the area Saturday evening, with the second shortwave moving across the area late Saturday night and Sunday morning. Precipitable water values are expected to peak in the 1.8 to 2 inch range, above the 90th percentile and approaching the top of the chart. While shear and helicity is sufficient for severe weather, current GFS forecast soundings indicate that instability will be lacking, but non- zero. NAM soundings are more favorable for severe weather on Sunday, so we can't discount the threat entirely. Current timing would have most precipitation diminishing beyond midday on Sunday.
Widespread 1 to 3 inch rain totals over the weekend appear justified. Heaviest rainfall expected to be west of Interstate 55, with a very low end chance (less than 10 percent) of 5 inch amounts, per NBM v5.0.

Beyond Sunday's system, the upper flow becomes northwesterly across the area with troughing along the East Coast. Several shortwaves will move toward the base of the trough. As each one passes to the northeast of the area, there will be a low end threat of convection, but the only one that the GFS indicates might have sufficient moisture to produce anything would be on the leading edge of a cold front at midweek, and even then, we're only talking about 20-30 PoPs right now.

Likely to continue to see above normal temperatures through at least Tuesday, although precipitation could hold temperatures on Sunday in the 70s. The northwest upper flow will eventually bring cooler and even drier air into the area, probably on Wednesday or Thursday. Seeing some indications that high temperatures may struggle to reach 70 degrees Wednesday and/or Thursday.

AVIATION
(18Z TAFS)
Issued at 1225 PM CDT Thu Oct 23 2025

VFR conditions in place, and expected through the forecast period.

MARINE
Issued at 1225 PM CDT Thu Oct 23 2025

Easterly winds around 15 knots should abate somewhat over the next few hours, so will not go with a short term headline. As onshore flow strengthens tomorrow night ahead of the next system, we will likely need Small Craft Advisories at some point late tomorrow night or Saturday morning over much of the open coastal waters that will carry into Sunday. Will not issue with the current package, per coordination with LCH and MOB. Conditions should improve somewhat for Monday and Tuesday, but hazardous conditions look pretty likely once the true colder air arrives at the middle of next week. But that's beyond the scope of the current marine forecast package.

PRELIMINARY POINT TEMPS/POPS
MCB 51 82 59 79 / 0 0 0 40 BTR 54 84 63 82 / 0 0 0 50 ASD 52 82 60 81 / 0 0 0 20 MSY 64 85 70 85 / 0 0 0 30 GPT 56 81 63 80 / 0 0 0 10 PQL 50 82 57 81 / 0 0 0 0

LIX WATCHES/WARNINGS/ADVISORIES
LA...None.
GM...None.
MS...None.
GM...None.