textproduct: Aberdeen

KEY MESSAGES

- High temperatures Today and Saturday will average 25 to 35 degrees above normal. Expect more seasonal temperatures from Sunday onward, with highs in the 40s to mid 50s Sunday. Milder temperatures follow through mid-week.

- Fire weather concerns remain over central/north central South Dakota through Saturday, with gusts this afternoon and Saturday afternoon around 15-30 mph. Afternoon humidity will be lowest in western and south central South Dakota at below 20%, with 20 to 30% across central/north central South Dakota.

- A front coming through Saturday late afternoon/evening will shift winds to a northerly direction with gusts around 25 to 40 mph. Any ongoing fires will be influenced by the wind shift and rapid increase.

DISCUSSION

Issued at 1237 PM CDT Fri Mar 20 2026

The upper level pattern shifts from one dominated by the southwestern CONUS heat ridge/upper high to more of a zonal/progressive pattern. No major waves within this pattern until possibly middle/late next week and even at that there is little confidence in timing/intensity of the wave depicted between deterministic guidance. As such focus remains on short term/fire weather potential.

After yesterdays way overachievement in temperatures, what is the potential we will underforecast highs again this afternoon? 850mb temperatures are a little cooler, on the order of 2C to upwards of 6C, a difference of approximate 4F to 10F degrees cooler on highs seems around right. Forecast from this morning appears right on the money, so no changes in regards to that. Looking at surface dewpoints, we are currently running in the 30s to mid 40s. CAMS and NBM continue to increase, like there is some form of ET that starts up. That may be related to some 'more humid' air aloft with northwest flow at 850mb advecting it into the CWA. That won't work great for central South Dakota but the higher values up in the northeast from NBM are probably ok. GFS/NAM BUFKIT profiles show mixing out by Pierre down to around 0C so tempered central South Dakota values a tad. For fire weather, we're still limited to marginal RH% and winds so again no headlines.

In regards to temperatures for Saturday, there is a plume of hotter air aloft with 850mb temperatures up to 15C to 22C at 09Z. With northwest flow, after that, we start seeing some weak cold advection. BUFKIT profiles show a really shallow inversion overnight as well, so it won't take much mixing to realize the heat aloft. We're also looking at less moisture aloft, so lower afternoon humidity. A surface low across the southern tier of the state will lead to less wind however, so the fire weather threat is limited in that respect. Through the afternoon/evening, we see the gradient across the northern tier of the state increase, with a rather rapid shifting of winds to northerly through the late afternoon/evening. NAM/GFS BUFKIT mixed winds top out around 30 to 35kts in the cold advection/favorable mixing environment. Fire weather concerns are thus heightened during this timeframe if any fires are ongoing due to the wind shift and better mixing environment.

Ahead of the front will also be a short period of enhanced winds for the downslope portions of the Sisseton hills Saturday morning. Just an hour or two or so as winds shift from south to west under that very strong inversion. Maybe gusts 40-50mph from BUFKIT profiles,

A mostly dry forecast continues. NBM probabilities of 0.01" are only 25% to 30% in/along the front late Saturday/early Sunday and its not until next Thursday in which we have another likewise equal chance. There is however a 10% chance for Monday, and deterministic models all have this in slightly different locations, and its essentially a blip in central/east central South Dakota. This is also when GEFS plums also have several of the members generate QPF. A deeper look into the GFS BUFKIT profiles indicates a mid level deck with some very weak ascent around 700mb, and there does appear to be a weak mid level warm advection push and the subtle-est of subtle shortwaves.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1237 PM CDT Fri Mar 20 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals. Some LLWS for the KATY terminal Saturday morning.

ABR WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None.