Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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072 FXUS64 KHUN 232022 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 322 PM CDT Mon Sep 23 2024 ...New NEAR TERM, SHORT TERM, and LONG TERM UPDATE... .NEAR TERM... (Tonight) Issued at 322 PM CDT Mon Sep 23 2024 Low chances (15-30%) of showers and storms (mainly along and north of the Tennessee River) will persist into this evening before diminishing due to the loss of daytime heating. Most of tonight is forecast to then be rain-free; however, chances are expected to increase to our northwest once again late tonight into early Tuesday morning due to the approach of a surface cold front. There is a low chance of patchy fog development tonight, but this should be confined to areas near bodies of water and in the more sheltered locations. Lastly, low temperatures tonight will be warm, merely dipping into the upper 60s to lower 70s. && .SHORT TERM... (Tuesday through Wednesday Night) Issued at 322 PM CDT Mon Sep 23 2024 A wet and unsettled pattern is expected to begin by Tuesday as a deep, upper trough digs towards the Southeastern US. Additionally, a surface cold front is forecast to approach the Tennessee Valley on Tuesday, then eventually slow and stall over our west or just to our west by midweek. This will lead to generally medium to high chances (50-80%) of showers and storms Tuesday through Wednesday night, with the time frame of the greatest rain chances being Tuesday night through Wednesday. Taking a look at the low chance of severe weather on Tuesday, guidance suggests that instability and bulk shear are the greatest along and west of I-65 during the day on Tuesday but may shift towards the east into the evening hours. Instability looks to range between 1500-2500 J/kg in the west and around 1000 J/kg in the east. Furthermore, bulk shear values mainly range between 30-40 knots. Models indicate a stout upper level jet around 85-95 knots as well. The question will be just how unstable we actually get during the afternoon, but the current thinking for timing of any potential strong to severe storms will be from 11 AM through 7 PM. SPC has outlooked most of our local area in a Marginal Risk (level 1 of 5) of severe weather tomorrow, primarily for damaging winds. Heavy rain may also lead to nuisance flooding, with forecast storm total rainfall between 1-3 inches (highest over northeast Alabama and portions of southern middle Tennessee) Tuesday through Wednesday night. The increase in rain and storm chances will ultimately bring a decrease in temperatures through midweek. Highs are expected to reach the mid 80s to around 90 degrees on Tuesday but only top out in the mid 70s to around 80 degrees for most areas on Wednesday. Low temperatures will follow a similar trend, falling into the lower to mid 60s by Wednesday night. && .LONG TERM... (Thursday through Sunday) Issued at 137 AM CDT Mon Sep 23 2024 3PM UPDATE: Bottom line up front is that there remains a fair bit of uncertainty in the track and evolution of Potential Tropical Cyclone 9. However, at this time, it looks like our main hazards with this system are shaping up to be heavy rain/flooding and potentially gusty winds. The flooding threat will be exacerbated by the rain from earlier in the week, with the potential for 5-7 inches of rainfall for northeast Alabama and portions of southern middle Tennessee by Friday night. Ultimately, like the previous shift mentioned, a westward shift in the track of the system would increase the potential of these impacts while an eastward shift would lessen the potential. We`ll continue to monitor this system through the coming days, so please make sure to stay weather aware! The long term part of the forecast will be heavily dependent on a potential tropical system out of the western Caribbean that will lift northward potentially making landfall along the eastern Gulf Coast in the Thu night/early Fri time frame. Where this system then tracks will determine how much additional rainfall the mid TN Valley may experience into the first half of the weekend period. If this system tracks more to the NNE versus the NE, the area could see some additional rainfall along with some gusty winds Fri/Fri night. However, a more eastern track may limit the rainfall/winds and provide more of a dry forecast this weekend. Regardless, highs look to remain in the upper 70s/near 80F this weekend, with lows more in the lower/mid 60s. && .AVIATION... (18Z TAFS) Issued at 1247 PM CDT Mon Sep 23 2024 VFR conditions will prevail at the TAF sites through at least tonight. A low chance (15-25%) of showers and perhaps a storm remains possible this afternoon but will diminish through early this evening. There is a low chance of patchy fog later tonight, but confidence is low whether this will impact the terminals. Therefore, left mention out of the TAFs for now. Rain and storm chances then increase through Tuesday morning to be 30-50% at MSL and 20-30% at HSV by late morning/early afternoon. Some breezy conditions may also accompany this potential into early Tuesday afternoon. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...26 SHORT TERM....26 LONG TERM....26/09 AVIATION...26