


Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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793 FXUS63 KABR 140932 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 432 AM CDT Mon Jul 14 2025 .KEY MESSAGES... - Near record heat around 100 degrees expected from Pierre south this afternoon. - There is a Marginal Risk (level 1 out of 5) of severe weather for the afternoon and evening hours Monday and Tuesday. On Tuesday, there is a Slight Risk (level 2 out of 5) for severe storms south of Hwy 212. Main threats include hail up to the size of quarters and 60 mph wind gusts. - Heavy rain is possible along and east of the James River into west central MN Tuesday through Wednesday. - There will be a noticeable cool-down midweek with highs potentially 15 to 20 degrees below normal Wednesday and 10 to 15 degrees below normal Thursday. && .SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/... Issued at 431 AM CDT Mon Jul 14 2025 Hot and dry conditions are expected through this afternoon with temperatures near Pierre and south topping out around the century mark. Winds and dewpoints in the 50s should keep apparent Ts right around, or just under, 100 degrees, ie. advisory criteria. Hi-res CAMs and global models develop weak low pressure across southwest SD this afternoon. A boundary extends northeast off the low into central SD after 22z. This boundary should be the focus point for convection along with some shortwaves that will move through in the evening. There is a marginal risk for severe thunderstorms northwest of a line from Victor to Vivian this evening. Main threats will be strong winds and quarter sized hail. Bulk shear of 30 to 40 kts with highest values across north central SD along with CAPE of 2000 to 4000 J/kg will help support storms. Lapse rates of 7.5 to 8.5 C/km may lead to microbursts. H7 temps of +13 to +14C across central SD provide a moderate cap, but the very warm temperatures should help convection to break through the cap. Low pressure shifts into central SD for Tuesday with a frontal boundary extending northeast into west central MN. Models have continued to waffle a little on this boundary placement and where the best moisture convergence sets up. However, anywhere north of the boundary, training and slow moving storms, especially when amplified by shortwave activity, may produce some heavy rain. PWATs over 1.5 inches are supportive of localized rainfall of 4+ inches, especially from Brown county east into the Sisseton hills. To the south, with the boundary, there is a slight risk for severe thunderstorms that creeps into the southern tier of the cwa with all threats possible. Strong winds and quarter sized hail remain possible north of the boundary, as well. && .LONG TERM /TUESDAY EVENING THROUGH SUNDAY/... Issued at 431 AM CDT Mon Jul 14 2025 Showers and thunderstorms (60-85%) will be ongoing Tuesday evening into early Wednesday morning as the CWA is forecasted to be just behind the cold front by then, associated with its surface low in MN, and shortwave aloft over ID/MT. This shortwave will push eastward across the Northern CONUS and weakening along the way as the cold front continues its path southeast. With help from this shortwave and surface troughing over the area behind the front, showers and thunderstorms are forecasted to continue Wednesday into Wednesday night before diminishing northwest to southeast over the CWA early Thursday. GEFS is the quickest on the departure of the precip with GEPS being the slowest. High pressure moves in behind the system and will be centered over the Northern Plains Thursday before shifting eastward on Friday. Zonal flow or slight northwest flow (depending on cluster ensemble) continues aloft through the weekend with precip possibly returning to the area Friday through the weekend as a couple of surface systems (and weak shortwaves aloft) pass over the region. The main concern continues to be the heavy rain potential Tuesday evening and Wednesday, especially with any slow moving and/or training of storms. NAEFS still indicates PWATS about 1 standard deviation above climo with values of 1.50" over the eastern half of the CWA between 00Z Wed-18Z Wed. Probability of 24 hr precip>0.50", per grand ensemble ending 00Z Thursday, is 45-55% James River Valley and eastward with a 15-20% chance of 1" or more for this same area. Deterministic NBM runs about 50-65% for 0.50" or more and 35-45% for an inch or more James River and eastward. However locally higher amounts are possible with any stronger storms or slow moving/training storms as mentioned. NBM 90th percentile QPF would be close to 2" to potentially 2.50" along and east of the Coteau into west central MN. EC EFI highlights QPF values of 0.5 to 0.7 east of the Mo River from 00Z Wed to 00Z Thursday with the highest values (and shift of tails of zero) James River and eastward which matches up with where the grand ensemble/NBM highest probabilities are. Lastly, there is a marginal risk for severe storms continuing through Monday evening, however, HREF indicates most of the severe threat should be to the south/southeast of the CWA by then with the front. Any slow down of the front would allow for an isolated severe threat in our area, mainly over south central to east central SD. By the middle of the week, it will feel more like fall as temp will run about 15 to 20 degrees below average on Wednesday and 10 to 15 degrees below average Thursday as cooler air sinks southward with the high. Forecasted highs look to range in the 60s to the lower to mid 70s Wednesday and upper 60s to mid 70s Thursday. 850mb temps will be about 1 standard deviation below climo ranging from 10 to 13C. EC EFI has values for TMAX of -0.6 to -0.9 over central SD on Wednesday and values of -0.8 to -0.9 over the entire CWA on Thursday with a shift of tails of zero for both days. Temps will warm back up Friday and the weekend in the 70s/80s to even around 90 over south central SD on Sunday. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1142 PM CDT Sun Jul 13 2025 Terminals KABR,KATY,KPIR,KMBG VFR conditions are forecast through the TAF period. Chances for TSRA enter the picture late in the period, generally 00-06Z Tuesday. Used PROB30 to convey this potential for the time being. Any heavier showers could bring MVFR/IFR VSBY, although CIGs may still remain VFR. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ SHORT TERM...20 LONG TERM...MMM AVIATION...TMT