textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 514 PM CST Thu Nov 27 2025 - Potential for a brief light freeze Friday morning for some areas north of Lake Pontchartrain and along Mississippi coast. This is primarily in the Pearl and Pascagoula River Basins.

- Hazardous marine conditions for much of the next 5 days.

- Entering a wetter pattern beginning Saturday night into Sunday, with a second period of rainfall, possibly heavy, Monday night and Tuesday.

SHORT TERM

(This afternoon through Friday night) Issued at 1128 AM CST Thu Nov 27 2025

Upper trough axis looks to be just to the east of the local area this morning, somewhere around Interstate 65, with ridging over the Intermountain West. At the surface, high pressure was centered near the Arkansas-Missouri border. Skies were clear across the area this morning with temperatures mainly in the 50s and dew points in the 20s.

The upper ridging to our west flattens quite a bit by Saturday morning, producing mainly zonal flow across the Gulf Coast States. The surface high will shift eastward to the Appalachians by that time. Precipitable water values near 1/3 inch are below the 10th percentile climatologically, and are expected to remain near that level through sunset Friday. Even by sunrise Saturday, those moisture levels are expected to remain below the 50th percentile, and forecast soundings would indicate no more than perhaps mid level clouds prior to sunrise Saturday.

Only real concern at this point is the potential for a freeze overnight tonight. The values currently in the grids would bring any real threat to primarily the Pearl and Pascagoula River drainages. Those areas have had a fairly significant freeze already, on the 10th and 11th, but we've had an unseasonably warm stretch since then. Secondary question is whether winds drop off enough tonight to allow decoupling for radiative cooling to maximize, and drop temperatures to or below freezing for a climatologically significant amount of time (several hours). Will hold off on Freeze Warning for now, but could adjust thinking this afternoon.

One adjustment from pure NBM that was made was to lower daytime dewpoints to NBM05 to NBM10 to better represent the very dry air across the area. Wind speeds are a bit below red flag criteria, but outdoor burning probably isn't a good idea at this point unless it is very well controlled.

LONG TERM

(Saturday through Wednesday) Issued at 1128 AM CST Thu Nov 27 2025

Onshore flow commences Saturday morning, with precipitable water values rebounding to around 1 inch by sunset Saturday. This at least sneaks above the 50th percentile climatologically. A northern stream shortwave will move across the Middle Mississippi River Valley Saturday afternoon and Saturday night, to near Lake Erie by Sunday morning. This will push a frontal boundary toward the area Saturday night, and through the area on Sunday. Precipitable water values only briefly get above the 75th percentile, so heavy rain threat with that system may not be as great as earlier thought. Rain amounts around an inch would actually be beneficial at this point.

Of somewhat greater concern will be the system that is expected to impact the area Monday night and Tuesday. The GFS and ECMWF are both forecasting a stronger shortwave to move across the Middle and Lower Mississippi River Valley, with precipitable water values reaching or exceeding the 90th percentile. The overnight medium range models also depict the development of a surface low along the frontal boundary as it moves across the area Monday night. This would be a more typical heavy rain threat than the weekend event, with the main concern timing of the frontal passage and low pressure development. Rainfall amounts of 1 to 2 inches look to be common. As this is Day 5-6, would expect details to resolve as the event gets closer, and with the weekend system 'priming the pump', a heavy rain/flooding event cannot be ruled out. Another brief shot of cold air will follow that system.

Current NBM numbers appear to favor the colder solutions for much of the long range period, but don't have any real ammunition at this point to back away from those.

AVIATION

(00Z TAFS) Issued at 514 PM CST Thu Nov 27 2025

A very dry and stable high pressure system over the area will keep VFR conditions in place at all of the terminals through the entire forecast period. Winds will remain gusty at NEW through tomorrow morning as increased thermal mixing over the warmer lake waters allows some stronger winds of 12 to 15 knots with occasional gusts over 20 knots to transport down to the surface.

MARINE

Issued at 1128 AM CST Thu Nov 27 2025

High pressure will gradually slide to the east over the next 36 hours. With cold, dry air continue to feed over the coastal waters, will extend the Small Craft Advisory over the open waters until 00z Saturday, and potentially beyond that point. Will likely need at least Small Craft Exercise Caution headlines over some or most of the protected waters Friday afternoon. If there is going to be a period of less impactful conditions across the waters over the next 5-6 days , it would probably be during the daytime hours on Sunday, until cold air behind that frontal passage reaches the waters.

PRELIMINARY POINT TEMPS/POPS

MCB 32 56 37 65 / 0 0 0 20 BTR 35 61 42 71 / 0 0 0 10 ASD 32 60 40 70 / 0 0 0 0 MSY 44 61 50 73 / 0 0 0 0 GPT 36 58 43 69 / 0 0 0 0 PQL 31 59 37 68 / 0 0 0 0

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...Small Craft Advisory until noon CST Friday for GMZ530-532-534- 536-538.

Small Craft Advisory until 6 PM CST Friday for GMZ550-552-555- 557-570-572-575-577.

MS...None. GM...Small Craft Advisory until noon CST Friday for GMZ532-534-536- 538.

Small Craft Advisory until 6 PM CST Friday for GMZ552-555-557- 570-572-575-577.