423 FXUS63 KFSD 232025 AFDFSD AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 325 PM CDT Fri Apr 23 2021 .SHORT TERM...(This Evening through Saturday) Issued at 324 PM CDT Fri Apr 23 2021 The surface low that has moved into the region today will continue to move eastward, causing winds in its wake to shift to northerly this evening and overnight. Behind this leading shortwave, the axis of a Canadian longwave trough reinforces cold air advection overnight. A dearth of moisture prevents precipitation for most, but south central South Dakota could see a dusting of snow as the cold front pushes through during the early AM hours Saturday. Saturday starts off cold and will remain that way with temperatures 5 to 10 degrees below average. Skies are forecast to be mostly clear, so the strong spring sun may make it feel slightly more mild; nevertheless, light north winds keep apparent temperatures in the 40s. .LONG TERM...(Saturday Night through Friday) Issued at 324 PM CDT Fri Apr 23 2021 A well-defined shortwave riding a building upper-level ridge Saturday night into Sunday will be the next opportunity for widespread precipitation. This system has a clear tie to Gulf Moisture, and forecast precipitation amounts have risen compared to the previous forecast. Ample frontogenesis should help squeeze out 0.25 to 0.50 inches of liquid equivalent north of I-90 across southeast South Dakota and southwest Minnesota. Temperatures remain quite cold over the Coteau des Prairies, causing several models to show a rain snow mix, or even pure snow, to this region during the morning hours Sunday. Therefore have raised snow amounts from De Smet, SD to Marshall, MN to Windom, MN. A quick inch or two of accumulation Sunday morning is not out of the question. That being said, the warm advective nature of this wave may cause snow production to be less stellar than usual. Additionally, south- southeasterly warm air advection throughout the day should help melt snow in a relatively rapid fashion, and warm surface and ground temperatures also aid in quick compaction. Stay tuned as even a 1 or 2 degree temperature shift in future model runs could change snow totals notably. Elsewhere, the warm advection Sunday afternoon brings upper 60s and low 70s to south central South Dakota. High temperatures vary a lot as one moves northeast, with Lake Andes, SD forecast to hit 72, whereas Marshall, MN may only get up to 45. Warmth spreads area-wide on Monday. Afternoon temperatures in the 70s to mid 80s are likely. A strong pressure gradient and decent mixing causes breezy conditions, with gusts 30 to 40 mph. Clouds increase Tuesday through mid-week. A slow-moving, quasi- stationary front directs several shortwave through the central Plains, with multiple rounds of rain possible. Drier weather looks likely Thursday through the end of the week as a ridge builds over the western CONUS. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1230 PM CDT Fri Apr 23 2021 Light winds with gusts up to 25 kt vary significantly in direction as a low pressure center moves through the region this afternoon. Cloud cover increases later this afternoon for locations that haven't already seen scattered to broken cumulus fields. This cloud deck sits largely near the MVFR to VFR (3000 ft AGL) threshold, but increases in height as one moves south. By sunset, winds will have shifted to northerly. Continued cloud cover is forecast as a mostly dry cold front pushes through. Sprinkles or even a few flurries cannot be completely ruled out overnight, but any accumulations would be minimal. Skies clear Saturday morning. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...VandenBoogart LONG TERM...VandenBoogart AVIATION...VandenBoogart