Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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988 FXUS64 KHUN 281733 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 1233 PM CDT Fri Jun 28 2024 ...New AVIATION... .NEAR TERM... (Rest of Today) Issued at 945 AM CDT Fri Jun 28 2024 The short wave that helped to instigate shower development across the area yesterday has moved southward to the N Central Gulf and in its wake, high pressure aloft is building across the region. With the lack of more significant forcing, shower/storm development will be limited mainly to areas of differential heating boundaries and low-level convergent flow axes. With that said, eastern portions of the area would appear to be favored for any development, which is reflected in the current POP forecast. Analysis of vertical thermal/moisture profiles suggests some strong downdrafts could occur if cells manage to develop, but confidence is fairly low that cells will reach significant growth. Otherwise, the invading MT airmass with dew points in the 70s combined with expected highs in the low/mid 90s will yield heat indices near 100 F in a few spots today. && .SHORT TERM... (Tonight through Sunday) Issued at 1258 AM CDT Fri Jun 28 2024 Upper ridging will gradually flatten as an upper shortwave trough moves over the Midwest Saturday evening and then over the Great Lakes and Ohio Valley on Sunday. At the surface, high pressure will meander westward from Florida over the northeastern Gulf of Mexico through the weekend. Meanwhile, a cold front will traverse the mid-Mississippi Valley and Ohio Valley on Sunday, approaching the Tennessee Valley. This pattern will keep abundant moisture in place and increasing chances for showers/storms through the weekend. For Saturday, low to medium chances (35-55%) of showers and storms are forecast for the northwestern portion of our local area and medium to high chances (55-70%) over the southeastern portion. Anticipating the best coverage of showers and storms on Sunday ahead of the aforementioned cold front, with medium to high chances (60-70%) of showers and storms. Once again, bulk shear values do not look impressive but we will have ample instability since it`s summertime. Therefore, expect brief, heavy rain, lightning, and maybe some gusty winds with any storms this weekend. Beyond the shower and storm chances, it will be hot. High temperatures are expected to reach the lower to mid 90s for most areas both Saturday and Sunday, with perhaps upper 80s to lower 90s for northeast Alabama and portions of southern middle Tennessee on Saturday. Moisture will be elevated through the weekend area-wide, along with lows merely dropping into the lower to mid 70s Friday and Saturday nights. At this time, heat indices range between 97-103 degrees for most locations on Saturday. Heat indices for a few spots in the Huntsville area and near Muscle Shoals may even reach the 105 degree mark. It will then be a little warmer on Sunday, with heat indices in the 99-105 degree range. We will have to keep an eye on Sunday afternoon for the need of any heat products, as it looks to be the hottest day (especially for heat indices) for the short term period. Again, please remember heat safety! Take frequent breaks in the shade, wear loose-fitting and light-colored clothing, and stay hydrated! Remember your pets too. If it`s too hot for you, it`s too hot for them! Take caution of hot pavement and make sure they are hydrated as well. && .LONG TERM... (Sunday night through Thursday) Issued at 1258 AM CDT Fri Jun 28 2024 Excessive heat will be the main story going into the latter half of the forecast period. A large upper ridge axis over the Plains states will begin to gradually move eastward heading into the new work week. At the sfc, high pressure will build eastward across the upper Midwest/Great Lakes regions in the wake of a departing cold front to the south. Lingering showers/tstms will also taper off to the south providing for a dry forecast at least thru Mon night. The passing frontal boundary should also translate into slightly cooler temps, with lows Sun night in the upper 60s/near 70F, before temps rebound into the upper 80s/near 90F later in the day Mon. The upper ridge pattern will then become entrenched across the Gulf Coast region starting Tue, with afternoon temps climbing into the mid/perhaps upper 90s. High pressure moving into the northern/mid Atlantic Basin will also result in SFC flow veering to the SE/S, thereby ushering moisture back into the central TN Valley. Max heat indices likewise may climb near/above 105F, especially on July 4th. Subsequently, Heat Advisories may be needed Wed and Thu. In addition to the excessive heat, diurnally driven showers/tstms (around a 20-40% chc) are possible starting Tue. Any convective activity will likely be pulse driven given ample buoyant energy, but little in the way of deep layer shear. && .AVIATION... (18Z TAFS) Issued at 1225 PM CDT Fri Jun 28 2024 VFR conditions are expected for the majority of the period at KHSV and KMSL terminals over the next 24 hours, however there is a slight chance (10-15%) of SHRA today, with SHRA chances increasing after 12Z Saturday. A narrow belt of increasingly agitated cu clouds can be observed in satellite imagery along portions of W AL, with this line stretching towards the KMSL area. Regional radars indicate lgt/mdt SHRA, but none near KMSL attm. Confidence is too low to include in TAF, but warranted a mention here. Otherwise, convection will be increasing tomorrow from the SE, with better chances of SHRA/TSRA at KHSV, especially after ~14Z. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...KDW SHORT TERM....26 LONG TERM....09 AVIATION...KDW