


Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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894 FXUS63 KFSD 121746 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 1246 PM CDT Sun Oct 12 2025 .KEY MESSAGES... - More scattered showers with an isolated rumble of thunder are expected this afternoon and evening mainly along and east of I-29. Any additional accumulations are expected to be light - Continued breeziness throughout the day could lead to high fire danger this afternoon. - An active pattern aloft will lead to additional rain chances (30%- 50%) during the middle to latter parts of the week. While severe weather is not expected, pockets of locally heavy rainfall will be possible. - After a brief return to below normal temperatures to start the week, near to just above normal temperatures return from the midweek onwards. && .DISCUSSION... Issued at 412 AM CDT Sun Oct 12 2025 Showers continue to move through the area this morning, aided by a 850 mb LLJ of 50-60 kts. Not all the rain has reached the ground due to a dry sub-cloud layer, but continued rainfall and the southerly LLJ should help moisten up the low levels through this morning to allow for better ground coverage by daybreak. Still, not expecting a lot this morning, with most spots seeing less than a tenth of an inch of rain. If a storm can develop within this weakly unstable environment, than perhaps you could see up to .15" or so. For today, a trough will eject through the northern Plains and help drag a cold front through the area. Additional shower development is possible this afternoon and evening along the cold front and in the immediate post-frontal environment before the low-levels dry up again. The best chance of this redevelopment will be along and east of I-29 where the low-levels will be a bit more saturated and so some spots may be able to pick up another few hundredths to a tenth of an inch of rain. So all told, most areas will see anywhere between 0.05 to 0.15," today, with locally higher amounts of 0.2" possible in a spot that sees a thunderstorm. Severe weather is not expected. Highs will be warm today in the mid-70s to low-80s due to strong southerly flow ahead of the front and the fact that we will likely see more breaks in the cloud cover than compared to yesterday. It will be breezy today, with gusts up to 30-35 mph, with some spots locally seeing a gust up to 40 mph. These winds could lead to an elevated fire weather threat in spots, but higher relative humidity values and rain chances will help prevent a more widespread fire weather threat. Winds will drop off quickly after sunset and any rain will come to an end from west to east this evening into early tonight as the low- levels dry up again. Cooler air filters in behind the frontal passage and so temperatures will drop into the mid-30s to mid-40s, coldest north of I-90 and west of I-29. There could be some patchy areas of frost by tomorrow morning mainly along the Highway-14 corridor from the Brookings-area into central South Dakota in the Chamberlain-area. Heading into tomorrow, another upper-low and its associated trough will dive into the Pacific Northwest. Downstream of this, guidance indicates a weak upper-wave moving in from western Nebraska into our area. There could be a few light showers associated with this tomorrow morning after sunrise, but dry low- level air should win out and so kept PoP`s very low (10% or less) for areas south of I-90. Another wave looks to move in later tomorrow into tomorrow night. Once again, a stout layer of sub- cloud dry air will be in place, but guidance indicates better coverage and more persistent showers which will likely saturate the low-levels enough to increase rain chances heading into Tuesday. Models are a bit split in how much rain we could see into Tuesday, so will keep the 30-50% PoPs from the NBM in for now. For Wednesday into Wednesday night, a low pressure system will develop out of the Rockies and lift northeastward into the western Dakotas, with a cold front draped southward from it. This will help increase rain chances for our area especially Wednesday night into Thursday, but confidence is low as details on development of this system are highly uncertain owing to it being several days out. Switching gears to temperatures this upcoming work week, temperatures will be near to below average through Tuesday, but another warm-up may be in tap for the middle of the week as some ridging aloft may build back into the area as we will be on the northern periphery of an upper-level high pressure system centered over Texas. Temperatures may cool-off again heading into next weekend as most guidance shows ridging being replaced with general troughiness. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1240 PM CDT Sun Oct 12 2025 Mostly VFR conditions will persist this TAF period. Taking a look across the area, mostly clear conditions continue this afternoon. While these conditions will hang around for the next few hours, should see a mid-level cloud deck develop overhead by late afternoon to early evening as a cold front approaches the area. Scattered shower will likely develop along and east of I-29 promoting occasional MVFR/IFR conditions mainly in the higher elevations areas in southwestern MN. Otherwise, breezy southerly winds will become more northwesterly behind the frontal passage this afternoon then light northeasterly winds overnight to end the TAF period. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Samet AVIATION...05