Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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652 FXUS64 KHUN 091831 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 131 PM CDT Sun Jun 9 2024 ...New NEAR TERM, SHORT TERM... .NEAR TERM... (This Evening and Tonight) Issued at 130 PM CDT Sun Jun 9 2024 A very mesoscale driven forecast this afternoon and evening across the Tennessee Valley. Ample heating has warmed temperatures into the mid to upper 80s as of 18z, with SPC mesoanalysis data showing SBCAPE values between 1500-3000 J/kg (with the highest values west of I-65). Low level lapse rates are still relatively modest, but are approaching 7 C/km over much of northwest Alabama. A couple of outflow boundaries are bisecting the area -- the most prominent one is currently stretching from central Arkansas, northern Mississippi and just south of the Tennessee River in northern Alabama. Another boundary stretches from near Muscle Shoals, AL to Crossville, TN. We will continue to monitor satellite and radar trends in the near term as they may serve as a focus convection by late this afternoon and into the evening hours as synoptic lift from an approaching shortwave increases forcing and bulk shear values increase to 30-40 kts. Main uncertainty remains where these boundaries will be located and when convection gets going. Based on the latest satellite trends, there is some evidence that these boundaries are drifting southward and it`s entirely possible that the window for strong to severe storms may be more limited this far north if storms initially convect to our south. Still, the presence of the more northern boundary in particular gives us confidence that eventually medium (40-60%) chances for showers/storms are warranted, especially in the 22-04z window as continually hinted at by the CAMS. We will be primed for damaging winds in clusters of storms that can organize into line segments during this window, with marginally severe hail and locally heavy rainfall secondary threats. This activity will begin to wane and sink south after Midnight, with PoPs lowering to around 20% by early Monday morning. && .SHORT TERM... (Monday through Wednesday) Issued at 130 PM CDT Sun Jun 9 2024 Rain chances will wane by early Monday morning as cloud cover gradually diminishes from north to south on Monday. A cooler, drier air mass will move into the region early next week and we`ll enjoy high temperatures only in the low to mid 80s for Monday and Tuesday, with overnight lows in the mid to upper 50s -- all to go along with sunny conditions each day. Ridging will amplify by midweek and a gradual warming trend will begin on Wednesday and carry over into the later part of the week. More on this in the section below. && .LONG TERM... (Wednesday through Saturday) Issued at 422 AM CDT Sun Jun 9 2024 Although specific details remain unclear at this point, most of the global models now suggest that that southern stream trough (discussed above) will travel southeastward into the northern Gulf of Mexico during the first half of the extended period, before evolving into nearly stationary cutoff low on Friday/Friday night. Any northward movement of the low next weekend will likely be dictated by the strength and orientation of a blocking mid-level ridge to its north, which will in all likelihood lie across the TN Valley, providing an extended period of warm and dry conditions that could potentially extend into the first part of the following week. That said, we have included a very low (15-20%) POP across our southeastern counties on Friday and Saturday afternoons, due to a gradual increase in low-level moisture which will translate to a notable increase in CAPE given hot daytime temperatures. Highs will quickly warm into the lower 90s for most valley locations by Thursday/Friday/Saturday, with lows more gradually returning to the u60s-l70s by Saturday morning. && .AVIATION... (18Z TAFS) Issued at 1132 AM CDT Sun Jun 9 2024 VFR conditions will be the predominant flight category this afternoon as a front approaches the region from the NW. Model guidance hints that a cluster/line of storms may develop and push into the region during a 23-05z timeframe. Have handled this with a TEMPO group for reduced visibilities and ceilings from TSRA during this timeframe. AWWs and amendments may also be needed if this occurs. TSRA chances will wane after Midnight and VFR conditions will return by Monday morning. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...AMP.24 SHORT TERM....AMP.24 LONG TERM....70 AVIATION...AMP