textproduct: NWS Birmingham

KEY MESSAGES

Issued at 622 PM CDT WED OCT 7 2026

- Tropical Storm Isaias is forecast to strengthen into a hurricane before making landfall on Friday evening along the Northern Gulf Coast.

- Winds may gust as high as 40 to 50 mph late Friday night through Saturday, resulting in the potential for scattered to numerous downed trees and power lines.

- Rainfall amounts of 2 to 4 inches with locally higher amounts up to 5 inches will result in the potential for flash flooding, especially in urban and other poor drainage areas.

- A threat for isolated tornadoes may develop along and east of I-65 on Saturday, with the relatively highest potential in far southeastern portions of Central Alabama, but confidence remains low at this time.

DISCUSSION

(This afternoon through Tuesday) Issued at 250 PM CDT WED OCT 7 2026

Tropical Storm Isaias Overview:

Tropical Storm Isaias continues to strengthen over the southwestern Gulf today. It will move slowly north-northeastward through tomorrow, before accelerating to the northeast and north Thursday night through landfall on the northern Gulf Coast Friday night as it phases with a southern stream shortwave trough. Models are slowly coming into better agreement, but there are still some typical differences in track and timing. In general the AI models remain further east than some of the physical models. Some models are also still a few hours apart on timing as well. It's important to remember that the center of the storm can track anywhere inside (or even just outside) of the cone, and that impacts can occur well outside the cone especially as the storm will be increasing in size during its extratropical transition. Given the fast-moving nature of the storm, the wind threat does appear to be increasing. The speed may decrease the flash flooding threat a bit, though with the potential for banding to occur the threat for some flash flooding does remain. The tornado threat remains uncertain, but is still worth keeping an eye on. Bottom line is everyone in Central Alabama needs to be prepared for tropical weather impacts.

Gradient/Tropical Winds:

While the storm's core will likely lose some organization as it moves into the area, low-level wind fields remain strong with 925mb winds around 60-70kts, and fast-moving systems are typically a bigger concern for winds. While a stable layer associated with the wedge will be a limiting factor for mixing down the higher winds, forecast soundings do indicate the potential for 40-50kt winds not too far off the ground. The high pressure to our northeast will also enhance the pressure gradient. Therefore, potential wind gusts look to be in the 40- 50 mph range with potential for locally higher gusts especially in the southern counties and also at higher elevations. This would result in scattered to numerous downed trees and power outages, which could be more widespread if the stronger solutions verify. Watches may become necessary as early as tonight.

Heavy Rainfall/Flash Flooding:

Drought remains ongoing over the area, but some areas did receive beneficial rainfall last weekend, especially our far southwest and far southeast counties. Streamflows remain below normal to well below normal for this time of year across West Alabama, while streamflows are closer to normal for this time of year (though normal is fairly low this time of year) elsewhere. This should minimize the risk of widespread main stem river flooding. Still, with copious tropical moisture transport there will be a threat for flash flooding, especially in urban and other poor drainage areas. Current forecast rainfall amounts range from 2-4" with locally higher amounts of 5". There may be a band of relatively lower rainfall amounts due to dry slotting somewhere between higher amounts west with the core of the system and higher amounts east with a north-south frontal band that sets up south of the center of the system, but placement of these features is uncertain. A Flood Watch may eventually be needed for portions of the area.

Severe Weather/Tropical Tornadoes:

Unsurprisingly, low-level shear and helicity values are high as the tropical system moves in. Mid-level winds/deep-layer shear values are higher than normal for a tropical system due to phasing with the upstream shortwave trough. The main limiting factor as it often is as we move into the cool season is instability. The cold air damming wedge and associated easterly winds resulting in evaporative cooling from isentropic lift driven rainfall will be the primary limiting factor for surface- based instability. At this time, the northeast quadrant of the storm looks stable as it moves in overnight. Starting potentially as early as the early morning hours on Saturday in our far southeast counties, a narrow corridor of instability may develop as the warm front lifts northward in tandem with the center of the system while a developing occluded front begins to move westward. Instability and shear profiles would be conducive for a potential for isolated, likely brief tornadoes mainly along and east of I-65 (though if western solutions verify this corridor would shift westward) during the day on Saturday, with relatively highest potential in our far southeast counties. This would be conditional based on placement of the convective band, with the approaching dry slot being a potential limiting factor where it suppresses convection. This threat will need to be closely monitored as we get closer and can assess the mesoscale trends.

32/JDavis

AVIATION

(00Z TAFS) Issued at 622 PM CDT WED OCT 7 2026

VFR conditions prevail throughout this TAF cycle. Light and variable winds tonight will increase to 5-8 knots out of the east during the day Thursday.

95/Castillo

FIRE WEATHER

Dry conditions are expected through Thursday. RH values will generally be in the 25 to 35 percent range Thursday afternoon. Rain chances and humidity begin to increase across southeast portions of the area Friday, while areas further to the northwest will have RH values in the 30 to 40 percent range. Fire danger for western and northwestern areas Friday as winds begin to pick up ahead of an approaching tropical system. Widespread rain and high winds are expected Friday night and Saturday as Tropical Storm Isaias moves through the area.

PRELIMINARY POINT TEMPS/POPS

Gadsden 52 89 58 84 / 0 0 0 0 Anniston 53 88 59 83 / 0 0 0 10 Birmingham 57 90 63 85 / 0 0 0 10 Tuscaloosa 57 93 62 89 / 0 0 0 10 Calera 56 90 61 84 / 0 0 0 20 Auburn 59 86 63 79 / 0 0 0 30 Montgomery 57 88 61 83 / 0 0 0 40 Troy 58 86 61 79 / 0 0 0 50

BMX WATCHES/WARNINGS/ADVISORIES

None.