Marine Weather and Tide Forecast for Guntersville, AL

NEAR TERM
(Rest of Today and Tonight)
Issued at 251 PM CDT Tue Aug 4 2026

There have been no significant changes to near term forecast reasoning since the update earlier this morning. Current thinking is that the coverage of ongoing moderate-heavy shower activity will continue to gradually increase through 4-5 PM, with a growing risk for thunderstorms during this timeframe as well. However, similar to yesterday, cells would likely need to sustain a 40-50 dBZ core in the 16-18 kft AGL layer for lightning to be a considerable threat, and this has not happened thus far today. It still appears as if at least isolated showers (and perhaps a few thunderstorms) will persist in the vicinity of a slow-moving surface trough through 0-2Z before dissipating later this evening.
As skies clear, light/variable winds will support the development of patchy but locally dense fog (particularly in locations that receive wetting rainfall today) as temps fall into the u60s-l70s.

Previous Discussion: An area of low pressure at the surface will travel westward across southern portions of GA/AL/MS today and tonight, as the parent cutoff upper cyclone drifts northward across GA and gradually weakens. As this occurs, a well-defined surface trough/streamline confluence axis (extending northward off the low) will enter northeastern AL later this morning, before progressing very slowly westward for the remainder of the day and night. In the presence of an otherwise unfavorable environment for lift aloft, low-level convergence in the vicinity of the trough (and in the presence of a moist boundary layer warming into the m-u 80s), combined with MLCAPE of 1000-2000 J/kg will be sufficient for the development of both showers and thunderstorms, initially beginning in the east between 15-17Z. With deep-layer NNE flow of 10-20 knots expected to persist in the circulation around the cutoff low, convective cells will be moving south- southwestward at a decent pace and this should limit the overall risk for flash flooding. However, lightning and heavy rainfall can be expected, along with brief strong wind gusts up to 40 MPH.

In similar fashion to yesterday evening, isolated showers and thunderstorms are expected to continue for a short period after 0Z (especially in the vicinity of the surface trough), but should dissipate between 2-4Z. As skies clear late this evening, conditions will once again become favorable for the development of patchy fog (some of which could be locally dense in locations that experience wetting rainfall later today). Overnight lows will be similar to those observed the past couple of nights (u60s-l70s).

SHORT TERM
(Wednesday through Thursday night)
Issued at 1056 AM CDT Tue Aug 4 2026

Over the course of the short term period, a cutoff upper low (initially situated to the immediate east of the CWFA) will open into a highly sheared trough as the northern portion of the wave becomes absorbed in the polar westerlies while the southern portion lingers across the central/southern Appalachians. In the low-levels, an increasingly diffuse surface trough/wind shift axis will exist across the central or western portion of the forecast area on Wednesday, and should once again initiate development of deep/moist convection by late morning (with additional showers and thunderstorms focused along convective outflow boundaries and in preferred regions of orographic ascent across northeast AL/southern Middle TN later in the afternoon). Shear will remain very weak tomorrow, and with similar values of MLCAPE (1000-2000 J/kg) and PWAT (1.8-2"), we expect lightning, locally heavy rainfall and brief strong winds to be the greatest impacts.
However, due to the decaying nature of the cutoff low, steering flow will back to the NW and diminish, resulting in slower cell motions to the southeast. Present indications are that this activity will dissipate by 2-4Z, with patchy fog expected during the early morning hours Thursday as temps fall into the u60s-l70s.

During the timeframe from Thursday-Thursday night, environmental conditions will become less conducive for convection as a mid- level ridge builds across much of the Gulf Coast and a Bermuda high expands southwestward in the low-levels (resulting in a light prevailing flow from the SSE). Nevertheless, at least widely scattered afternoon thunderstorms are expected in our region on Thursday (perhaps most concentrated in the elevated terrain of the east), but overall coverage should be lower (especially as slightly drier air may spill southwestward from the Appalachians).
Due to a lower coverage of afternoon clouds/precipitation, highs will return to the u80s-l90s, with overnight lows rising into the l-m 70s Friday morning.

LONG TERM
(Friday through Monday)
Issued at 930 PM CDT Mon Aug 3 2026

On Friday, the ridge to our west will expand and provide an increase in heat concerns that will persist through the weekend.
Otherwise, there's a low to medium chances (20-40%) for diurnal showers and thunderstorms with the greatest coverage east of I-65.
This weekend, moisture will wrap around the western side of the subtropical ridge out in the Atlantic and bring an increase in rainfall, low to medium (30-60%) chances Saturday through Monday.
Highest coverage will again be east of I-65. Highs will be in the upper 80s to lower 90s Friday through Monday but heat index values will push above 100 degrees. At this time, values remain just below Heat Advisory criteria however trends will be monitored.
Regardless, practice heat safety!

AVIATION
(18Z TAFS)
Issued at 1251 PM CDT Tue Aug 4 2026

VFR conditions currently exist at the HSV/MSL terminals, featuring sct-bkn Cu con beneath a bkn layer of Ac. Over the course of the aftn, a subtle sfc trough/wind shift axis will shift slowly westward across eastern/central portions of north AL, focusing the development of SHRA/TSRA. At this point, probabilities for direct impacts at both terminals appear low (but comparatively higher at HSV) and for this reason we have included a PROB30 group in TAFHSV from 18-23Z (highlighting the timeframe when AWWs for lightning may be required). Lingering evening convection should dissipate by 2-4Z, with clearing skies and lgt/vrbl flow expected to support development of patchy BR/FG.
However, due to uncertainties in rainfall coverage invof the terminals, we will not include MVFR vsby reductions attm. A sct- bkn Cu field will redevelop by the end of the period, and although SHRA/TSRA may evolve once again prior to 18Z, confidence in coverage is not high enough to include at this point.

HUN WATCHES/WARNINGS/ADVISORIES
AL...None.
TN...None.