New Orleans/Baton Rouge, Louisiana

New SHORT TERM, LONG TERM, AVIATION, MARINE

• Wind speeds will slack off some over the Gulf but expect them to remain out of the east through Monday and pick back up to 15 to 20 knot mainly over open gulf waters. This will continue 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.
• Stronger system impacts the region Tuesday and Wednesday. Rain will begin during the day Tuesday impacting election day while strong to severe storms look possible Tuesday night through early Wednesday.

The remnants of Vance will linger in the area through the day, bringing only scattered showers and light rain amounts. Our next weather maker is already starting to slowly take shape but it is a complete mess right now, with models treating conditions just enough differently that Tuesday and Wednesday resolve into more or less rain and chance for severe weather. By Monday it should be a rather deep L/W trough having just crossed the Continental Divide while mid lvl ridging dominates the region. As we head into Election day things start to pick back up but the forecast is definitely not clear cut and confidence honestly has taken a bit of a hit with the latest medium range model guidance.

Focus on the extended portion of the forecast is our system Tuesday and into Wednesday. Models had come into much better agreement the last few days well there is definitely some disagreements with respect o how they handle the mid lvl pattern and the multitude of features. This has lowered confidence quite considerably in the forecast for Tuesday and Tuesday night. We will still see a pretty decent system along with a front which will bring showers and thunderstorms to the area the question though is timing and intensity. Because of that there were NO adjustments from the latest NBM.

Models are struggling with how to handle everything with respect to the large L/W trough off the west coast and the mid lvl jet coming out of the east Pac and merging into it tomorrow night over the 4 corners region. Typically with that much wind and most of the mid lvl jet downstream of the trough axis it should want to pull the trough north/lift it out and along with that most of the dynamics. There are some issues though. There will still be some strong mid lvl winds upstream of the trough axis and then there may be another strong s/w diving south out of Canada Monday night and into Tuesday.

A few different options then occur. First if that strong s/w develops and dives south out of Canada it would cause the L/W trough to rapidly close off and much farther north, over the north-central CONUS. This would then leave a much weaker trough axis at the base moving into the Lower MS Valley maybe even be held back to the southwest leading to a slower time frame. This also has any sfc reflection well north of the area and not much of a front moving into the region. We would still see rain and some thunderstorms but the risk for strong to severe storms would greatly be reduced. This also may keep a good chunk of Election day on the drier side thanks to a slower time frame.

Another option would be if that s/w doesn`t develop or is much weaker as it drops south. It still looks like the trough would close off given all of the energy that merges with it over the 4 corners but it would be a much broader closed low and it would close off farther to the southwest. This would lead to a much more defined and sharper trough axis and possibly even take on a negative tilt as it tries to move through Tuesday night. The main associated sfc low would still be well north but there would likely be a weak wave along the front farther south closer to the region. This scenario would continue to lead to the threat of strong to severe storms along with locally heavy rain. It also has more potential for showers and maybe some embedded thunderstorms during the day which would impact voting sites.

Right now this system is still in the Pacific and with this much energy the models are struggling. We should hopefully begin to tighten things up tomorrow as it finally begins to move into the upper air network we start to get some better data and sampling. With that like was said earlier stuck with the NBM which has high PoPs Tuesday afternoon through Tuesday night and then tapering off during the day Wednesday. Rainfall amounts being advertised right now is not overlie impressive but those will get adjusted as well depending on how thins evolve. After this move through we move into more zonal flow and and dry out the rest of the work week.

All terminals at IFR to MVFR due to low CIGs; this should last through about 12Z/daybreak. Into the day will range from MVFR again due to CIGs to VFR. Scattered showers may impact individual terminals and are coded as PROB30 statements.

Into early next week 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 may see slightly higher winds of 15 to 20 knots over this period, resulting in choppier seas of 3 to 6 feet. Winds look like they slack off tonight enough to keep headlines out for now but there is a good chance the outer waters will need SCS headlines again Sunday and possibly through Monday. This persistent east wind will also lead to some minor coastal flooding less than one foot above ground level for east facing shores through the remainder of the weekend. We are already seeing some showers and a few thunderstorms which will continue tonight and Sunday as a weak disturbance passes through.

LA

Coastal Flood Advisory until 9 AM CST this morning for LAZ070-076-078.

GM

None.

MS

Coastal Flood Advisory until 9 AM CST this morning for MSZ086.

GM

None.