Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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487 FXUS63 KFSD 100854 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 354 AM CDT Mon Jun 10 2024 .KEY MESSAGES... - An active pattern aloft will promote periodic rain chances for most of the week. - While uncertainty continues with the potential severe weather risk, the focus continues to be on Wednesday and Thursday afternoon. - Temperatures will continue to trend above normal towards the middle and latter parts of the week with highs expected to be in the 80s and potentially low 90s. && .DISCUSSION... Issued at 348 AM CDT Mon Jun 10 2024 The Short Term (Today & Tonight): A warm and marginally breezy day will be on tap for the day. Taking a look across the area, mostly clear conditions continue as an upper level ridge moves into our area from the northwest. After a relatively mild start to the day, ample mixing along with increasing warm air advection (WAA) on the backside of the ridge will lead to temperatures peak in the upper 70s to mid 80s with the warmest conditions expected west of I-29 and along the Missouri River Valley. Southeasterly surface winds will become a touch breezy this afternoon especially west of the James River as the SPG tightens leading to wind gusts between 20-30 mph. By tonight, heights begin to fall as an mid to upper level trough pushes eastwards across the Dakotas late this evening with its associated cold front leading to development of scattered showers with a few isolated thunderstorms. Current model trends continue to have any developing activity pushing into our western-most counties after 00z. While the likelihood of severe weather continues to be low, there is some potential for stronger wind gusts if a strong thunderstorm can develop a strong enough cold pool in our western most counties. However, with a statically stable environment overhead due to the departing surface ridge; any lingering activity should gradually weaken as it approaches the I-29 corridor. Nonetheless, accumulations should be fairly light with up to tenth or two possible as most of the activity exits the region by Tuesday morning. The Long Term (Tuesday-Sunday): Heading into the extend period, the warming trend continues into the midweek as quasi-zonal flow returns aloft behind the cold front. As heights begin to rise with the arrival of a mid-level ridge by Tuesday afternoon strengthening WAA along with deep mixing will lead to much warmer temperatures through Wednesday as temperatures reach up to 97th percentile of climatology according to the ESAT Tables. With this in mind, highs will sharply increase from the low to upper 80s on Tuesday to the upper 80s to mid 90s by Wednesday. On top of that, most ensemble guidance continue to hint at increasing low level moisture on Wednesday as the heat continues to build. With over 30 percent of members showing dew points in the upper 60s to low 70s, conditions will likely feel hot and muggy for a good bit of the afternoon. Make sure to wear lighter clothing if possible! Shifting gears to our precipitation chance, another mid-level wave will slide through the region along with its associated cold front by Wednesday afternoon bringing some increased precipitation chances (40%-50%). Looking at the environment, the heat and humidity will help promote moderate instability values (1500-2500 J/kg) of MLCAPE and 40-50 kts of deep layer shear which are consistent among deterministic guidance. However, now the question becomes if the wave will arrive early enough to take advantage of the unstable environment. With slight timing differences among guidance with the waves arrival, its still a bit hard to say at this moment which has led to a bit of uncertainty on the severe weather risk. Nonetheless, we`ll continue to monitor the trends over the next few days to get a clearer picture. The uncertainty will continue into Thursday as another cold front swings through our area throughout the day promoting more precipitation chances (10%-20%) by the afternoon. While the environment doesn`t look quite as good as the previous day, strong deep layer shear (40-50 kts) and isentropic lift ahead of the near-surface boundary could help promote a few scattered showers and thundershowers. However, the risk for severe weather should be low given the better instability vector is to our south. Looking into the weekend, heights will begin to rise as a strengthening ridge moves into the region by Friday. While there is some potential for increased precipitation chances by Saturday, timing and intensity differences among long-range guidance has led to uncertainty. Lastly, the above normal temperatures will continue into the weekend with highs expected to vary between the upper 70s to upper 80s. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1042 PM CDT Sun Jun 9 2024 VFR conditions are expected to prevail this TAF cycle. Should see light and variable winds continue overnight and most of the morning hours, with direction turning more southeasterly during the afternoon. Gust between 15 to 25 MPH will be possible along and west of the James River. Otherwise, could see some showers and storms impact those along and west of I-29 after sunset, though confidence remains too low to include anything more than a PROB30 at this time. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Gumbs AVIATION...SST