177 FXUS63 KABR 170440 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 1140 PM CDT Wed Apr 16 2025 .KEY MESSAGES... - There is a 25 to 45 percent chance of rain showers tonight through Thursday night, with accumulation generally under one tenth of an inch. - Rain shower chances (20 to 30 percent) continue for Sunday afternoon through Monday morning, with a 20 to 40 percent chance of one tenth of an inch or more of rainfall occurring, mainly east of the James River valley over into western Minnesota. - The coldest day in the period looks to be Friday, with highs in the 40s to lower 50s. && .UPDATE... Issued at 640 PM CDT Wed Apr 16 2025 No significant changes have been needed so far this evening. Temperatures were a little higher this evening, with a slower cool down expected. Otherwise, winds will be diminishing to 7-10kts over the next hour before increasing after the passage of the cold front/surface low tonight into Thursday morning. && .SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/... Issued at 310 PM CDT Wed Apr 16 2025 An upper level ridge currently over the region will exit to the east tonight, with a more southwesterly flow developing between the exiting ridge and a trough over the western part of the country. The trough will dig southward west of the Rockies Thursday and Thursday night, with some scattered shortwave energy riding up the east side of the trough and over the CWA tonight through Thursday night. At the surface, a frontal boundary currently over western South Dakota will work its way eastward and across the CWA tonight through Thursday morning. In combination with the upper level energy, will see the potential for scattered showers beginning later this evening through Thursday night. Widespread rainfall is not expected, and total accumulations at any one location will generally be less than one tenth of an inch. Cooler air will also work its way in behind the frontal passage, with temperatures on Thursday a good 10 to 20 degrees cooler than today. As wind shift to the northwest behind the front, will see the speeds increase into the 20 to 35 mph range during the day Thursday, with some gusts as high as 40 mph at times, especially across central South Dakota. The wind speeds will diminish some Thursday night, but will still be in the 10 to 20 mph range overnight. Low temperatures tonight will be in the upper 30s to mid 40s. High temperatures on Thursday will range from the upper 40s across north central South Dakota to the lower 60s across far northeastern South Dakota and west central Minnesota. Lows Thursday night will be in the lower to mid 30s. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 310 PM CDT Wed Apr 16 2025 The long term period opens Friday morning with southwesterly flow aloft and a deep trough off to our west. The GFS and NAM show a low moving across far northern ND Friday night into Saturday morning. The EC shows this upper level low just park over far northern SD and southern ND and move across the ND/SD border Sunday evening into the overnight hours. Once the low moves out, upper level ridging or zonal flow builds in for the start of the work week. We are starting to see some signal of an upper level low Tuesday afternoon into at least Wednesday morning, with a surface low and cold front moving through late Monday into Tuesday. On the precipitation side of things, some light rain (20-30% PoPs) will continue into Friday morning along and southeast of line from Sisseton to Pierre. There is a chance that some snow could mix in during the early morning hours. This will come to an end sometime during the morning hours. Sunday afternoon/evening, some light showers are possible mainly east of the James River, again 20-30% PoPs. Accumulations from this are expected to be very light, maybe up to a tenth of an inch. The best chance for precipitation during the period looks to be Monday afternoon through Tuesday with widespread 25-40% PoPs moving in from the west. Accumulations during this event have a 30-40% chance of exceeding a tenth of an inch. Temperatures during the period are still expected to be right around average with the warmest day being Monday as we get some southerly winds ahead of the cold front and low. Friday looks to be the coldest day with highs 5-10 degrees below normal. Speaking of winds, Friday looks to be the windiest day of the period with gusts of 25- 30 mph possible mainly east of the Missouri River. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1139 PM CDT Wed Apr 16 2025 Terminals KABR,KATY,KPIR,KMBG VFR conditions will continue through 10Z, with low end VFR to high end MVFR ceilings move in to MBG and eventually across the entire forecast area behind the surface low/cold front. The highest chance of MVFR ceilings will be at ATY, with MVFR conditions expected from 15Z through the end of the TAF period. Another concern will be gusty winds. Winds just above the surface at ABR are gusting out of the S-SSE at 40-50kts. Have added low level wind shear there until 09Z. Winds behind the boundary are gusting 20-30kts, and will move across the TAF sites through the day Thursday before slowly diminishing west to east. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...06 SHORT TERM...Parkin LONG TERM...13 AVIATION...06