textproduct: Huntsville

KEY MESSAGES

Updated at 1119 AM CDT Sat May 2 2026

- There is a low chance for showers late this afternoon and early this evening. A few instances of wind gusts up to 30-40 MPH and perhaps some small graupel may occur with the heavier showers.

- Conditions will become favorable for the development of fog beginning late this evening (some of which could become widespread and dense early Sunday morning). Spotty frost may also develop in isolated cold spots across southern TN/northeast AL.

- There is a low risk for strong to severe storms on Wednesday.

NEAR TERM

(Rest of Today and Tonight) Issued at 236 PM CDT Sat May 2 2026

There have been no significant changes to near term forecast reasoning since the update earlier this morning, with current radar data indicating an expanding coverage of showers from western KY into southwestern TN. Although present indications are that our forecast area will be impacted by this regime later this afternoon, a very dry boundary layer will likely yield only a few sprinkles of rain (at most) with low reflectivity cells. However, should a heavier core materialize, steep low-level lapse rates suggest that wind gusts up to 30-40 MPH and small pellets of graupel will both be possible. Any lingering convection will dissipate by 2-3Z (if not sooner) with conditions becoming favorable for development of fog early Sunday morning as temps fall into the u30s-l40s.

Previous Discussion: In the mid/upper-levels, a deepening cold core vortex will lift slowly northward across western Quebec today and tonight. An initially positively-tilted longwave trough axis attached to the vortex is expected to shift east-southeastward across the TN Valley later this afternoon, before taking on a more neutral tilt tonight in response to an upstream speed max digging southeastward across the northern Plains and Upper Midwest. At the surface, a developing area of low pressure across north FL will advance northeastward to a position off the coast of NC by late this afternoon, before deepening more substantially off the northern Mid-Atlantic Coast overnight. Although the peripheral stratiform rain shield on the northwestern flank of the low is now well to our southeast, an overcast altostratus layer (and some patches of virga) in its wake will persist across eastern portions of the CWFA for much of the morning, limiting diurnal warming to some extent.

Throughout the late morning and into the afternoon hours, weak convection is predicted to expand in coverage from southern IL southeastward through the Lower OH Valley and into portions of western and Middle TN as synoptic scale ascent strengthens downstream from the approaching upper speed max. Some of this activity may indeed reach the local forecast area by mid-afternoon (20-21Z) and persist through ~2-3Z, and we have made a slight increase in POPs during this timeframe to reflect lastest solutions from both the global models and higher-resolution CAMs. A deep-well mixed boundary layer (extending up to 6-10 kft) is evident in forecast soundings, and this could result in some instances of brief wind gusts up to 30-40 MPH and perhaps even a few pellets of graupel with any higher reflectivity cores, but with temps in the m-u 60s only supporting CAPE up to 150-200 J/kg the risk for lightning will be very low. Skies will quickly clear by late this evening as the convective regime dissipates, and with a broadening surface ridge expected to lie across the region, conditions will be favorable for the development of fog (some of which could become widespread and dense) as temperatures fall into the u30s-l40s. Although a few patches of frost may also occur in isolated colder spots across southern Middle TN/northeast AL, coverage does not appear high enough to warrant special headlines at this point.

SHORT TERM

(Sunday through Monday night) Issued at 1119 AM CDT Sat May 2 2026

Dry northwest flow aloft will prevail across the TN Valley on Sunday/Sunday night, as our region will remain under the influence of a cold core vortex in the process of making a cyclonic loop across southeastern Canada. As the axis of a remnant surface ridge continues to shift southeastward and away from the region, light- moderate southwesterly return flow and abundant sunshine will yield warmer afternoon highs tomorrow (u60s-l70s in the valley), followed by a sharp gradient in low temps Monday morning (l40s/NE to l50s/NW). Although upscale growth of nocturnal convective clusters is predicted to occur along an axis from the MO-Valley into eastern KY Sunday evening (as a westerly low-level jet strengthens in advance of a northern stream shortwave trough digging into western Ontario), this activity will remain safely displaced to our north and dry conditions will continue for the local area. During the period from Monday into Monday night, mid- level winds will back to the west-southwest, which along with a modest strengthening of southwesterly flow in the low-levels will lead to a continuation of the warming trend, as highs return to the u70s-l80s Monday and lows warm into the l-m 50s Monday night.

LONG TERM

(Tuesday through Friday) Issued at 952 PM CDT Fri May 1 2026

An anomalous cold pattern should continue across much of the North American domain, courtesy of a rather deep upper low situated over southern Ontario and Quebec. The presence of this vortex has created lower heights across the eastern CONUS, with resultant cooler than normal temperatures. By the time we get into later Monday, lower than normal mean upper heights should be situated over southern Ontario. Another upper level system developing west of Vancouver will slowly deepen as it moves southward across the central California coast on Monday. It will eventually become part of a synoptic scale through that should move eastward across the Lower-48 in the next work week.

This next system could produce higher terrain snow in the Rockies early next week, as a surface low develops over the Front Range and adjacent High Plains. As it traverses more to the east, this storm system will tap more moisture from the Gulf region. Closer to this region, surface high pressure will move east of the Tennessee Valley on Monday, inducing a southerly flow and also bringing deeper moisture from the Gulf. An associated cold front nearing from the west will bring an increase in clouds, along with chances of showers and thunderstorms. General model output this far out was suggesting that some storms during Wednesday afternoon and night-time could become strong to severe in intensity, along with locally heavy rain. The upper trough as it sweeps across the Ohio/Tennessee Valley region also become neutrally tilted, which can help enhance overall storm intensity.

A cold front with this next system should move across the area on Thursday. Given the presence of the upper level vortex hanging tough over the Hudson Bay, producing inherently lower heights, and a NW-N surface flow as Canadian high pressure builds over the region, will bring more unseasonably cool conditions to close out the latter work week.

For the extended period, daily temperatures for the start of a new workweek should be a tad milder, with lows Sunday night from the lower 40s east to lower 50s west. High temperatures in the Tuesday through Wednesday period should risen into the mid/upper 70s, a little cooler than seasonable norms of around 80. After the front passes Thursday, highs that day should only rise into the lower 70s, and in the low/mid 70s next Friday.

AVIATION

(18Z TAFS) Issued at 1258 PM CDT Sat May 2 2026

A deep, well-mixed boundary layer will exist across the region today, beneath cold temperatures aloft. This setup will promote development of sct-bkn high-based Cu capable of providing intermittent VFR cigs in the 4-10 kft layer. A few SHRA may also occur invof the terminals (mainly between 20-21Z and 2-3Z) but due to limited coverage, we have not included this in the official forecast at this point. However, should a stronger shower directly impact either HSV or MSL, brief wind gusts of 25-35 knots and perhaps some pellets of graupel could occur. Skies will become clear late this evening, with lgt/vrbl-calm winds supporting the development of BR/FG early Sun morning. Although the extent of vsby reductions is unclear, a TEMPO group has been included from 9-13Z to address this potential impact. VFR conditions and a lgt SW flow will return by the end of the TAF period.

HUN WATCHES/WARNINGS/ADVISORIES

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