Old Jefferson, LA 70817 Weather

: NEW AVIATION:

Key messages

Updated at 614 PM CDT Fri Oct 30 2026

- Wind speeds will remain in the 15 to 20 knot range mainly over open gulf waters keeping small craft headlines to be posted in addition this will help to create minor coastal flooding along sections of the Mississippi and Louisiana gulf coasts during high tide times each day through the weekend. A coastal flood advisory is in effect for locations expected to get minor coastal flooding.

- Rain returns to the area Saturday with the best chance of rain likely Saturday afternoon through midday Sunday possibly impacting some Halloween Trick-or-Treating or parties.

- Stronger system impacts the region Tuesday and Wednesdays next week. Rain will begin during the day impacting election day while strong to severe storms look possible Tuesday night through early Wednesday.

Short term

(Now through Monday night) Issued at 133 PM CDT Fri Oct 30 2026

Main concern for this weekend is your Trick-or-Treating forecast. As we have been mentioning all week it doesn't look like a complete washout but after 3 weeks of dry weather rain decides to return on Halloween day, yeah not cool. That said the forecast for this weekend and especially tomorrow afternoon through midday Sunday is not extremely clear. There is no real focus or low level feature/front to grab and there will be multiple weak mid lvl disturbance moving through the southwest flow aloft. First more noticeable s/w is currently moving north over southern TX and along the lower TX coast. This disturbance or atleast a piece of it will move through the Lower MS Valley tonight and will help to prime the airmass by greatly aiding in moisture recovery however not much outside of a few very light showers are expected with this.

The more likely time for rain will be when what looks like the leading peace of energy associated with the nose of the mid lvl jet quickly races east-northeast across the border of AZ/NM/Mexico and into northern TX by midday tomorrow. This disturbance then moves east into the Lower MS Valley tomorrow afternoon and evening increasing the lift over the area. That will combine with PWs that may actually approach 2" and this should have little problem getting showers to start developing across the region. There isn't a great deal of instability but there will be some so expected some embedded thunderstorms with the activity tomorrow evening and night. Most likely locations for storms will be over the Gulf where the better instability will reside however adequate forcing and at least some mid lvl instability will allow for a few thunderstorms inland.

As mentioned earlier there is no real feature in the low level or boundary layer do this may be more of a just a dreary afternoon and night with numerous light showers and isolated to scattered moderate heavy showers/storms. Overall most of the region likely see half and inch or less but there is one area that could see maybe as much as 2 inches of rain and that could be coastal MS and perhaps backtracking to the northwest east of McComb. Even though this is not a very dynamic system there is a potential for storms to line up or even back build from northwest to southeast overnight and through Sunday morning. From around Tyler town southeast towards the central/eastern MS coast there will be a time frame where there is some decent LL confluence. At the same time the jet will dive southeast into the Gulf placing the northeastern half of the CWA under the LFQ with very strong upper level Diffluence. The combination of these two features overnight and early Wednesday could combine with just enough instability over coastal MS and to the northwest that a few more efficient thunderstorms could develop leading to slightly more rainfall in those areas. Given this setup and that much moisture available it would not be a complete shock to see one or two locations receive a could inches of rain if not slightly more. /CAB/

Long term

(Tuesday through Thursday night) Issued at 133 PM CDT Fri Oct 30 2026

The extended portion of the forecast is a little more concerning. Models continue to come in fairly decent agreement with a very sharp trough swinging through the MS Valley region Tuesday night and early Wednesday. Models a few days ago were in disagreement by as much as 24-36 hours but trended much closer in time frame yesterday and remain that way today. With decent agreement in the operational models and their associated ensemble means and given that this system is still back in the Pacific and 5 days out we will stick close to the latest NBM.

As for our system Tuesday and Wednesday. Ridging that quickly built back in behind this weekends system will quickly be ushered out Monday night and early Tuesday. This system will move onshore over the Pacific coast Sunday while a strong subtropical jet coming across the Baja will merge into the base of it over New Mexico early Monday. This will sharpen the trough as it moves into and across the Plains Monday night and early Tuesday. This will also lead to Lee-side cyclogenesis likely around eastern CO with this sfc low deepening as it lift to the northeast/east- northeast towards the Upper MS Valley by Tuesday afternoon. A cold front will extend south all the way into TX and will be on knocking on the door of the Lower MS Valley by late afternoon/early evening. As we move into the evening and overnight hours the trough will continue to sharpen up as the axis starts to swing through the central CONUS/MS Valley possibly taking on a negative tilt overnight as it moves through the Lower MS Valley. This will provide very strong forcing across the region easily producing showers and thunderstorms along and likely ahead of the front.

As said early this system is still in the Pacific so expect some refinement and changes as it starts to move into the upper air network maybe as early as Sunday morning and with that we won't get into all of the details however this is looking like a potent system with the potential to bring strong to severe storms across the area. A neutral to possibly negative tilt trough will traverse the area. winds will respond at all levels with a LL jet possibly developing along and maybe just ahead of the front overnight. Mid lvl flow of 40 to 50 kt out sw/ssw while at the same time we may move under a coupled jet structure from aloft. All of this just continues to hammer the impressive amount of forcing and lift we will have. So the question could be instability. We don't get completely cleaned out by out system this weekend but we will see drier air move in at all levels of the atmosphere. PW's may drop to 1.25" or lower but dewpoints could drop down into the lower 60s and we don't really begin to see any type of recovery kick in till late Monday possibly even overnight. Even with the rather dynamic system, with the sfc low so far to our north the response in the boundary layer is more muted than all other areas and thus the recovery period will be slower. In addition there are some indications that we could see some decent coverage of isentropic lift/WAA showers through much of the day. This would hurt daytime heating and thus keep the overall instability down some.

The possibility of some decent rain coverage during the day and lower instability is the main thing that is keeping this system from really becoming a big concerns for our area from a severe weather standpoint. However, this is a very dynamic system with a lot of forcing and that can and has many times in the past helped to overcome any lack of instability. With that we will need to watch this system closely as the main time frame at this point appears to be the evening and overnight hours which is always a bad time for severe weather. In addition rain and possible thunderstorms during the day Tuesday could impact polling sites on Election Day. /CAB/

Aviation

(00Z TAFS) Issued at 617 PM CDT Fri Oct 30 2026

VFR conditions continue through the overnight with some increasing clouds by Saturday morning. CIGs drop to around 5000ft by afternoon as isolated showers and storms develop toward the end of the cycle. For now covered with PROBs. Easterly winds will increase a bit too, especially coastal terminals where some gusts of 15 to 20kts will be possible. (Frye)

Marine

Issued at 133 PM CDT Fri Oct 30 2026

A prevailing easterly wind will remain in place across the waters through the upcoming weekend and into early next week as a broad surface high pressure system sits to the north of the area. Winds will generally remain in the 10 to 15 knot range in the lakes, sounds, and bays through the weekend and into early next. However, the open Gulf waters will see slightly higher winds of 15 to 20 knots over this period, resulting in choppier seas of 3 to 6 feet. Smaller craft should exercise caution if venturing out into the open Gulf waters. This persistent east wind will also lead to some minor coastal flooding less than one foot above ground level for east facing shores starting through the weekend. There will be some passing showers and a few thunderstorms for Saturday and Sunday as a weak disturbance aloft passes through, but no significant impacts to maritime activities are expected from the weak thunderstorms that do develop. /CAB/

Watches, warnings and advisories

LA: Coastal Flood Advisory from 1 AM to 9 AM CDT Saturday for LAZ070- 076-078.

GM: None. MS: Coastal Flood Advisory from 1 AM to 9 AM CDT Saturday for MSZ086- 087.

GM: None.