


Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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472 FXUS63 KABR 262334 AAA AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 634 PM CDT Thu Jun 26 2025 .KEY MESSAGES... - Severe storm chances return Friday afternoon through Friday night, with a slight risk (level 2 of 5) for severe weather across the entire forecast area. Main threat includes large hail, potentially 2" in diameter or larger, wind gusts between 60-70 mph, and a few tornadoes. - Additional chances for severe weather continue Saturday/Saturday night with a slight risk (level 2 of 5) for severe weather mainly along and south of Highway 12. - Temperatures will remain rather warm along with higher levels of humidity on Friday through the weekend. Drier conditions will be possible early next week as warm temperatures continue. && .UPDATE... Issued at 626 PM CDT Thu Jun 26 2025 See below for an aviation forecast discussion for the 00Z TAFs. && .DISCUSSION... Issued at 302 PM CDT Thu Jun 26 2025 The main concern in the forecast package will be the scattered severe storms possible Friday and Saturday over the forecast area and the return of summer like temperatures these days. As of 3pm, radar indicates light to moderate rain continuing to fall mainly east of the Coteau with the last of the rain forecasted to exit the far northeastern CWA this evening. We are seeing some clearing over western SD and portions of central SD on the backside of this system. The ongoing low level moisture and post-rain will lead to more fog overnight into early Friday morning. EC meteograms highlight this well with Conshort indicating a bit more broader in coverage than what we saw this morning, mainly along and east of the Mo River. Some of this fog could be dense at times especially over the James River Valley and Coteau. This has been added to the grids and an advisory may be needed if we see visibilities drop to less than 1/4 mile. The shortwave and its associated low pressure system will be off to our east this evening with zonal to slight northwest flow aloft as a low amplitude ridge moves in over the area this evening and shifting eastward into MN on Friday, bringing a relief to the soggy weather. A weak amplitude trough sets up and extends over the Pacific Northwest this evening through Friday. Within this trough, a stronger shortwave will push east/northeast on the downwind side of the trough. The axis of this shortwave is forecasted to be over MT/WY and western Dakotas into Canada by 00Z Saturday. Winds will be increasing to 40-50kts from 300-500mb and 700mb winds increasing to 25-35kts with these winds highest over MT/ND. By Friday evening, its center of the low looks to hover the Saskatchewan/Manitoba border with central to portions of northeastern SD within the warm sector between the warm front and cold front, will will be over western SD along with a lee low. So with upper air support and lift from the front will aid in convection, however, the better lift looks to be over ND and northward, closer to the low. Within the warm sector, return flow at 850mb will bring in more low level moisture and warmer air with winds between 20-30kts and dewpoints rising between 10-15C by the afternoon and evening with temperatures 20-25C in this area. With this WAA, surface temps are expected to rise in the 80s the lower 90s, warmest over central SD, with dewpoints in the mid to upper 60s to possibly the lower 70s. This will lead to moderate to strong instability (and help break the daytime cap as 700mb temps range from 9-12C) as HREF Surface/MUCAPE will increase between 1000-3000j/kg, with the 2-3K values over central SD. The potential max values could be up to 4000-5000 j/kg in this area! EC EFI highlights values 0.6-0.8 for CAPE and CAPE- shear over central SD for this enhanced threat. With the increased winds aloft, bulk shear will run between 30-40kts and mid level lapse rates between 7-8C. STP values between 1-2 run from north central SD through southeastern SD where we see the greatest 0-1km SRH (up to 100m2s2). HREF 2-5 UH>75m2s2 paintballs indicate organized convection could fire up as early as late afternoon (~22Z) but more in two areas to start. One area over north central SD into ND and the other area over central/south central SD into southern SD/northern NE. This northern convection, per HREF, becomes more numerous as it pushes eastward. UH>150m2s2 indicates these cells could be right moving supercells over central to northeastern parts of SD. So if we can get convective initiation, it will not take much for these storms to become severe with what was mentioned for severe parameters. The SPC has expanded the slight risk (level 2 out of 5) and now covers the entire CWA. The main threats include large hail with a 10% hatched area along and west of a line from Aberdeen through Redfield, meaning 10% or greater chance for hail to be at and over 2" in diameter within 25 miles of a point (due to this supercell potential). There is also the threat for a few tornadoes with any supercells with a 2% chance within 25 miles of a point along and west of the James River to the Mo River. Winds gusts between 60-70 mph is also a threat. The embedded shortwave will be over the southern portions of Canada/Northern CONUS by Saturday afternoon and evening with the surface low/boundary shifting eastward. Temperatures are expected to rise into the upper 80s to the lower 90s and dewpoints in the upper 60s into the lower 70s with similar instability/shear setup as Friday. EC EFI has a larger area of 0.6-0.8 for CAPE from southern SD through northeastern SD into MN with a shift of tails of zero. With this ongoing instability, severe storms are possible again as SPC has a slight risk (2/5) mainly along and south of Highway 12. Lastly, we continue in this moist setup as PWAT values will still 1- 2 standard deviations above climo Friday and Saturday with values up to 1.25" along and east of the Mo River Saturday and along and east of the James River Sunday. Mean specific humidity still ranges about 2 standard deviations above climo from 850-925mb. So with any thunderstorm that forms, it does have the potential to produce heavy downpours. Any training of these storms could lead to an increase potential for flooding. Overall dry weather expected Sunday into early next week with temps in the 80s to lower 90s. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 626 PM CDT Thu Jun 26 2025 Terminals KABR,KATY,KPIR,KMBG All four terminals should be precipitation-free through the TAF valid period. While KPIR/KMBG are VFR right now, low clouds/fog are forecast to return after 06Z tonight and persist until a few hours after sunrise on Friday. KABR/KATY remain socked in under an MVFR stratus layer. Guidance suggests that later tonight, ceilings will lower and/or fog will develop (as it has the previous two nights...persistence), resulting in a period of IFR conditions at KABR/KATY through appx 15Z Friday before there is any potential for flying weather conditions to improve at those two terminals. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...10 DISCUSSION...MMM AVIATION...10