textproduct: Huntsville

KEY MESSAGES

Updated at 1048 AM CDT Fri May 29 2026

- A medium-high (50-90%) coverage of showers and thunderstorms is expected from today through Saturday. Lightning and heavy downpours will be the main impacts.

- Coverage of showers and storms will begin to decrease on Sunday and Monday (becoming focused across northern/western areas), with dry and mild conditions expected Tuesday-Thursday.

NEAR TERM

(Rest of Today and Tonight) Issued at 155 PM CDT Fri May 29 2026

There have been no major changes to near term forecast reasoning since the update earlier this morning. Latest CAMs suggest that convective showers and thunderstorms (currently in progress across northeast AL/southern Middle TN) will progress northeastward and out of the region between 20-22Z, as light rain persists across the western half of the CWFA. However, the coverage of showers and storms is expected to increase region-wide early this evening, as convection spreading northeastward from MS enters the region and begins to interact with an eastward-moving outflow boundary. The primary impacts from thunderstorms will be gusty winds (perhaps up to 40 MPH), lightning and heavy downpours which may result in localized flash flooding. As evening convection begins to slowly dissipate during the early morning hours, conditions will quickly become favorable for the development of very low stratus clouds and fog (some of which could be locally dense) as temperatures fall into the m-u 60s.

Previous Discussion: A weak but negatively-tilted 500-mb shortwave trough will lift slowly northeastward across Lower-MS Valley today, providing a modest increase in deep-layer southwesterly flow across our forecast area. In the low-levels, a lengthy axis of streamline confluence will exist from MO southeastward through the TN Valley and into southern GA along the interface of easterly flow (related to a weakening surface high over the Lower Great Lakes) and southerly flow (related to a small low over AR and stronger lee cyclone across eastern CO).

Current thinking is that areas of light rain will continue to spread northward over the CWFA through the remainder of the morning, within a warm/moist advection regime to the east of the shortwave trough. As occasional breaks in the overcast altostratus layer permit limited insolation beginning early this afternoon, thunderstorms are expected to evolve in the vicinity of both the broader confluence axis and any mesoscale boundaries as CAPE rises into the 1000-1500 J/kg range (perhaps a bit higher in some locations). Cells and clusters will shift northeastward with time and eventually exit the region shortly after 0Z. Lightning and locally heavy rainfall will be the main impacts from thunderstorms (with PWAT values in the 1.8-2" range), but due to a slight increase in southwesterly steering flow, the risk for flash flooding will be a bit lower compared to yesterday.

Although both coverage and intensity will be lower, the risk for scattered showers and thunderstorms will persist across the entire region overnight as the shortwave begins to turn southeastward in the flow around an amplified northern stream trough digging into the northeastern CONUS. Steering flow, however, will veer to the west during this period, with cells traveling eastward and exiting the eastern portion of the forecast area shortly after 12Z Saturday. As temperatures slowly fall into the l-m 60s and winds subside, conditions will become favorable for the development of widespread and perhaps locally dense fog and low stratus clouds early Saturday morning.

SHORT TERM

(Saturday through Sunday night) Issued at 1048 AM CDT Fri May 29 2026

Beginning late tonight and continuing through Saturday night, a reinforcing dome of Canadian high pressure will build southward through eastern Ontario and into the Great Lakes as a northern stream trough digs southeastward off the coast of New England. This will force a lengthy low-level confluence axis southwestward through the local forecast area tomorrow in the form of a backdoor cold front. In spite of minor height rises and subsidence in the wake of a weaker shortwave disturbance (that will cross the region early tomorrow morning), showers and thunderstorms are likely to develop along this feature by late morning and spread southeastward with time under the influence of strengthening northwest flow aloft. Due to an abundant coverage of low clouds and fog early in the morning, CAPE values will likely be similar to today. However, as mid-level winds begin to rise into the 25-30 knot range, a few more organized clusters may eventually develop, increasing the risk for strong/SPS-caliber wind gusts.

Light northeast flow in the boundary layer is predicted to advect a slightly drier airmass into much of the region beginning Saturday evening, with any lingering convection expected to dissipate within an hour or so of sunset. Overnight lows will be a few degrees cooler as a result, with some locations in northeast AL perhaps reaching the l60s early Sunday morning. Present indications are that dry air will continue to be advected into the region on Sunday, as minor cold air damming becomes established in the lee of the Appalachians. With this in mind, chances for afternoon convection will likely be limited to the western half of the CWFA (where POPs remain in the 60-70% range at the current time). With the dry airmass being reinforced across our eastern zones Sunday night, temps may fall into the u50s early Monday morning, with dry conditions expected after any afternoon convection dissipates early in the evening.

LONG TERM

(Monday through Thursday) Issued at 955 PM CDT Thu May 28 2026

A pattern change bringing drier conditions will arrive for the start of the new work week. Through the long term, mid level ridging will build over the Plains and slowly push east. This coupled with surface high pressure building over the Great Lakes region will suppress on high rain chances and bring in much drier conditions. Rain chances will drop to below 30% each afternoon. Likewise, the building high pressure will push our current muggy dew points further south, replacing them with more comfortable dew points in the high 50s to low 60s. Moderate temps also look to remain through the long term thanks to high pressure to our north with highs topping out in the low to mid 80s each day.

AVIATION

(18Z TAFS) Issued at 102 PM CDT Fri May 29 2026

Local radar data indicates light rain across the western portion of the forecast area, with development of cellular convection (more capable of producing lightning) now in progress across the east. Current thinking is that MVFR cigs will remain intact at both airports, and that TSRA will be more of a concern for HSV early in the period before cells eventually progress northeastward and away from the terminal after 21Z. Although it appears as if low clouds may temporarily disperse around 0Z, chances for SHRA/TSRA will increase once again this evening as convection in closer proximity to a surface low (currently across AR) spreads northeastward from MS and begins to interact with an eastward- moving outflow boundary. Thus, we have included PROB30 groups for TSRA at MSL/0-6Z and HSV/2-8Z to account for this scenario. In the wake of late evening precipitation, very low stratus clouds and BR/FG appear likely early Sat morning, with diurnal mixing promoting improvement in conditions beginning around 15Z.

HUN WATCHES/WARNINGS/ADVISORIES

AL...None. TN...None.