textproduct: Huntsville

KEY MESSAGES

Updated at 1107 AM CDT Sat May 9 2026

- A low (15-25%) chance for thunderstorms will exist Sunday afternoon, mainly focused across northwest AL. A few strong storms capable of producing gusty winds and small hail may occur.

- Medium (25-45%) chances for showers and thunderstorms will exist Sunday night and early Monday morning. A few strong storms may occur, mainly during the evening hours.

NEAR TERM

(Rest of Today and Tonight) Issued at 226 PM CDT Sat May 9 2026

There have been no significant changes to near term forecast reasoning since the update earlier this morning. However, with overcast cirrostratus clouds (originating from convection along the Gulf Coast) likely to mute the diurnal temperature curve to some extent, we will make a minor downward adjustment to afternoon high temps. It still appears as if a differential heating boundary on the northern edge of the cloud shield may initiate a few showers along a broad axis from southern AR across our region and into the southern Appalachians between 22-0Z, which could linger into the evening before dissipating. Although only small parts of the area may receive rainfall, POPs were increased slightly (into the 10-20%) range to reflect solutions from the latest CAMs. As skies partially clear later this evening, conditions will become favorable for development of fog (some of which could be widespread and dense), as temps descend into the m-u 50s.

Previous Discussion: Cyclonic flow aloft will persist across much of eastern North America for the duration of the near term period, anchored by a cold core vortex across northern Ontario. Embedded within this flow, a southern stream vort max will progress eastward from TX into the central Gulf Coast, becoming increasingly sheared with time as it enters a region of confluent flow to the northwest of a subtropical ridge centered near the Bahamas. In the low-levels, light southwesterly flow will exist across the TN Valley, between a surface low across southern Ontario and a ridge extending from the western North Atlantic into the Lower MS Valley.

Present indications are that clusters of showers and thunderstorms related to deep-layer warm/moist advection ahead of the southern stream wave will remain confined from LA into southern GA/north FL today and should not have an impact on local weather conditions. However, a subtle prefrontal surface trough/wind shift axis may initiate a few showers in our region very late this afternoon (in the presence of a sufficiently moist airmass with CAPE of 250-500 J/kg), which could linger through 2-4Z before dissipating. Presuming that low stratus clouds lift/scatter this afternoon (as indicated in point forecast soundings), highs will likely reach the u70s-l80s. Due to light southerly winds and dewpoints creeping into the u50s-l60s, overnight lows will be a few degrees warmer (compared to last night) and in the m-u 50s. Conditions will become quite favorable for the development of fog beginning late this evening, with transition into a low stratus deck anticipated prior to sunrise.

SHORT TERM

(Sunday through Monday night) Issued at 1107 AM CDT Sat May 9 2026

Short range model data suggests that a lengthy cold front (extending from western NY/PA southwestward through the OH Valley and into the southern TX Panhandle at the beginning of the period) will make steady southeastward progression on Sunday/Sunday night as a Canadian high (in its wake) builds into the northern Plains and Upper MS Valley. As low stratus clouds and fog disperse late Sunday morning, diurnal destabilization (temps rising into the l-m 80s) and dewpoints in the lower 60s will boost CAPE into the 500-1000 J/kg range (highest across the southwestern portion of the CWFA). It appears as if a few thunderstorms may evolve from northern MS into western TN by early afternoon, perhaps aided by lift from a remnant MCV originating from widespread convection later tonight across OK and western AR. Should this activity spread eastward into northwest AL late tomorrow afternoon, westerly flow aloft of 30-40 knots (coupled with sufficient CAPE) may yield a few strong updrafts capable of producing wind gusts up to 40-50 MPH and sub-severe hail.

Otherwise, the greatest coverage of showers and thunderstorms will likely occur on Sunday evening as the cold front drops southeastward through the region. Although instability will decrease with time after sunset, deep-layer shear will remain adequate for minor updraft organization. However, the greatest risk for widespread severe storms will remain displaced to our southwest, where a couple of organized clusters will track southeastward in the general region from central TX into the Lower MS Valley. In the wake of the front, mid-level ascent will strengthen ahead of an approaching 500-mb trough, and this should support an expanding region of weak postfrontal convection from eastern AR into the central Appalachians Sunday evening. This activity will progress southeastward (likely impacting at least a portion of our CWFA early Monday morning), with additional rainfall and perhaps some sporadic lightning being the primary impacts. Rain will largely end from NW-to-SE late Monday morning, with gusty NNE winds advecting a cooler/drier airmass into region as high pressure builds into the Great Lakes. Highs will only reach the l-m 70s on Monday, and with conditions favorable for radiational cooling, lows should fall into the m-u 40s Monday night.

LONG TERM

(Tuesday through Friday) Issued at 940 PM CDT Fri May 8 2026

This surface high spreads eastward over the northeast and southeastern CONUS during the day on Tuesday. More sunshine on Tuesday despite continuing strong cold air advection should allow highs to climb into the upper 60s to lower 70s mainly (normal high at KHSV is 80 degrees).

Also, on Tuesday, a strong upper low moves southeast through NW flow aloft from central Canada towards the Ohio Valley area. A surface front develops southwest from this upper level feature into Tuesday night through Missouri and Oklahoma. Good forcing and increasing low level moisture (though meager) ahead of that front could produce some precipitation ahead of it in those areas.

This activity will remain far north of the area into the early overnight hours on Tuesday. However, models differ shortly after that timeframe if precipitation approaches southern middle Tennessee before 7 AM on Wednesday.

Most of the mid/upper level forcing seen in current guidance stays closer to the Ohio Valley and then pushes southeast towards the Carolinas. This should be where the better chances of rain and maybe thunderstorms would occur.

However, by Wednesday afternoon most guidance does converge on some better forcing edging southwest into the area along/ahead of the surface front. Shear will be decent (40kts or so), but forcing and SBCAPE (only ~ 100 J/KG) will be very spotty and weak. Some isolated to scattered strong storms may not be out of the question, but with forcing so weak along the front, confidence is extremely low even with strong storm development.

AVIATION

(18Z TAFS) Issued at 1244 PM CDT Sat May 9 2026

Visible satellite imagery and regional sfc obs indicate that early morning stratus clouds are rapidly lifting/scattering early this aftn. However, a bkn-ovc layer of higher-lvl As/Cs will continue to spread northeastward, providing VFR cigs for the remainder of the day. Forecast soundings suggest that skies will gradually become more clear after 0Z, and this along with diminishing SSW winds and abundant low-lvl moisture will support development of BR/FG late this evening. Thus, we have included MVFR vsby reductions in a TEMPO group from 4-8Z, after which time the fog is expected to transition into another low stratus layer that will bring MVFR cigs from 8-16Z (perhaps IFR btwn 9-13Z). A return to VFR conditions and a SW flow of 5-10 kts is expected by the end of the TAF period.

HUN WATCHES/WARNINGS/ADVISORIES

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