Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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714 FXUS64 KHUN 262356 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 656 PM CDT Sun May 26 2024 ...New AVIATION... .NEAR TERM... (Rest of Today and Tonight) Issued at 2 PM CDT Sun May 26 2024 Heat will remain a concern through the rest of the day as temps rise into the high 80s and low 90s with real feel temps in the mid 90s. The partly cloudy conditions right now are priming the environment for our severe threat later tonight. The warm moist air is quickly destabilizing the boundary layer with 1500-2000 J/KG of CAPE developing through the afternoon and lingering into the overnight hours. Our very unstable environment leading up to tonight has been well represented in model trends and is currently verifying very well. Our severe threat tonight will come as a surface low pressure system passes us to the north. A broken line of storms will move through our area ahead of the attached cold front. The broken line of storms and overall timing of the line have both been well represented in the models. Current timing remains from 1AM - 7AM, give or take an hour or two. Models continue to show favorable parameters for all severe hazards tonight. Lingering CAPE of 1500-2000 J/KG along with low and mid level lapse rates between 7-8 C/KM will support a threat for large hail. The orientation of the line along with bulk shear of 45-60 KTS will support damaging winds preforming as our primary threat. Models have yet to align on supporting both strong directional and speed shear. This is yielding high uncertainty in the development of a higher confidence tornado threat. Consensus between the models certainly supports the risk for one or two embedded tornadoes however if direction shear increases, this would increase our tornado risk. Further mesoanalysis throughout the afternoon using both model soundings and surrounding offices soundings will help us refine the tornado risk. Three other factors we will be assessing throughout the evening is the presence of a CAP, impacts from any mid-level dry air, and prefrontal convection. Models are again inconsistent in resolving both a CAP and dry air in the profile. My current assessment is that we will likely start off the event CAPED with a decent amount of dry air. I expect the ongoing storms to our north to quickly moisten the profile and for the CAP to erode as the line moves through. That being said, the presence and persistence of both of these features would hinder both our tornado potential and the strength of the line overall. As for prefrontal convection, this would likely be diurnally and outflow boundary driven, thus the models are slow to highlight it. Any storms that do develop this afternoon will again be in a very favorable environment for all convective hazards. Regardless of how our tornado threat evolves, straightline winds can be equally as damaging and warrant the same need to prepare. Before you go to bed, make sure you have a plan and have multiple ways to receive warning including those that will wake you up while you sleep. && .SHORT TERM... (Monday through Wednesday) Issued at 2 PM CDT Sun May 26 2024 Storms should be exiting the area just after sunrise on Monday morning. While light rain and low clouds may linger into the morning, clearing should begin by mid day yielding a mostly clear and dry afternoon with highs in the mid 80s. The remainder of the short term will see surface high pressure build in from the NW. High pressure will keep us calm and dry through the remainder of the short term with a slight cool down on Wednesday with temps only reaching the low 80s. && .LONG TERM... (Wednesday night through Saturday) Issued at 351 AM CDT Sun May 26 2024 As upper level ridging moves in from the Mississippi Valley through end of the work week, dry weather and mostly clear skies will continue to dominate the long term period. Friday afternoon through Saturday, low chances (30% or less) of showers/storms are possible as an upper level shortwave forms in the lower Mississippi Valley. Otherwise, high temperatures during this time are forecast to be in the upper 70s to 80s with overnight lows in the 50s/60s. && .AVIATION... (00Z TAFS) Issued at 656 PM CDT Sun May 26 2024 VFR conditions will prevail through the early overnight hours ahead of a strong storm system expected to move through the area near and after midnight. Gusty south/southwesterly winds will persist through much of the overnight hours, with MVFR cigs arriving around 01z. Large hail, damaging winds, tornadoes, and heavy rain will all be possible with these storms overnight through Monday morning, and amendments to the TAFs may be needed overnight. Reductions to IFR/LIFR conditions are likely in heavier thunderstorms, between 06-12z being the greatest threat window. VFR conditions should resume by 12-14z. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...RAD SHORT TERM....RAD LONG TERM....HC AVIATION...25