textproduct: Huntsville

KEY MESSAGES

Updated at 927 PM CST Thu Nov 20 2025

- Widespread Dense fog reducing visibilities below a mile tonight into Friday morning across much of northern Alabama and our Tennessee counties.

- Two rounds of storms Friday, the first during the early afternoon with a low chance of strong to severe storms Friday night into Saturday.

- High chances for showers and storms Monday night into Tuesday with a low chance for strong to severe storms.

NEAR TERM

(Today) Issued at 444 AM CST Fri Nov 21 2025

Much of northern Alabama and southern middle Tennessee remain socked in with lows clouds or dense fog. The exception to that is likely in Cullman county, where winds have remained closer to 6 or 7 mph much of the night. This fog may begin to slowly lift from the southwest around daybreak over the next few hours. However, most areas will continue to see 1/2 to 1/4 or less visibilities through then. A Dense Fog Advisory was extended to include all counties in northern Alabama except Cullman county and remains in effect until 8 AM CST. Our southern middle Tennessee counties are also included in that Advisory.

Models continue to show better forcing pushing back into the area from the west during the morning hours today. However, most the guidance keeps the stronger forcing mainly near and south of the Birmingham, AL area. However, a few models do extend the northern edge of that stronger forcing into portions of Cullman and possibly Marshall county during the early afternoon hours. There is much uncertainty whether the instability will build that far east before the forcing exits into Georgia. If any convection does develop during that period, there is a low chance it could be strong to severe. The primary threat looks like damaging winds and some heavy downpours at this time. With the dense fog this morning followed by increasingly deeper cloud cover and rain this afternoon, highs should be a tad cooler today, only reaching the upper 60s to around 75 towards Cullman county. At this time, helicity looks too meager during the afternoon for much of a tornado threat.

SHORT TERM

(Friday night through Sunday Night) Issued at 444 AM CST Thu Nov 21 2025

As we head into Friday night, showers and storms are forecast to develop along a prefrontal trough axis across MS and W TN. The storms arrive into NW AL around midnight and then quickly move east overnight. Looking at the 00z CAMs, there is quite a bit of uncertainty in both storm coverage and intensity. This is likely due to a lack of forecast instability as bulk shear is expected to be between 40-50 knots with 0-3 km shear between 25-35 knots. If a strong storm can develop in a low instability and weakly forced environment, then they would be capable of producing damaging winds and possibly a tornado. However, confidence at this time of severe storms is low, especially on the tornadic threat. Most likely scenario appears to be a broken line of showers and storms weakening as it progresses east through our local forecast area.

Light showers or drizzle may continue during the morning on Saturday before a cold front sweeps through the area from NW to SE. The post frontal airmass will not be much cooler, but some drier air will filter in from the NW. As a result, dry weather is forecast through the remainder of the weekend. Temperatures both Saturday and Sunday will rise into the upper 60s to lower 70s with overnight lows in the low to mid 40s.

LONG TERM

(Monday through Thursday) Issued at 927 PM CST Thu Nov 20 2025

On Monday, a deep upper level trough across the Western US with a low pressure system centered over the Rockies will shift eastward across the Plains. To the south of the low, a cold front will push through the Tennessee Valley Monday night into Tuesday. Medium to high (60-80%) chances for showers and storms are forecast with the frontal passage. Something to keep on eye on for this system is the potential for strong to severe storms. Right now there is still too much disagreement in the medium range guidance, but wind shear looks quite favorable for storms. However once again the lack of instability may limit the severe potential. Once the front clears the forecast area by the second half of next week a much cooler and drier airmass arrives into the Tennessee Valley. Afternoon highs only reach the low 60s on Wednesday and then the low to mid 50s on Thursday with overnight lows in the upper 20s to lower 30s.

AVIATION

(06Z TAFS) Issued at 1044 PM CST Thu Nov 20 2025

Fog, some locally dense has developed this evening across northern AL. Expect reductions in visibilities at times at both HSV and MSL. Fog should lift by morning with some mid levels clouds moving overhead. Showers develop around lunchtime which will reduce both visibilities and ceilings. And isolated thunderstorm is also possible, but have left out of this update due to low confidence in coverage. Additional showers and storms may impact far NW AL, but timing appears just after the end of this TAF period at 06z.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Dense Fog Advisory until 8 AM CST this morning for ALZ001>010.

TN...Dense Fog Advisory until 8 AM CST this morning for TNZ076-096- 097.