Watertown, SD Weather

Key Messages

- Temperatures today and Wednesday will be 10-20 degrees warmer than normal, with highs in the upper 60s to mid 70s. Then there is the potential for temperatures to be 15-25 degrees above normal Thursday and Friday.

- Dry conditions continue through Thursday with rain chances (30- 50%) potentially returning Friday night into Saturday. Low confidence in exact track and of the system along with estimated rainfall amounts at this time.

Discussion

Issued at 122 AM CDT Tue Oct 20 2026

An upper-level ridge has moved over SD and it will stick around over the areas through Thursday. It is helping to support southerly winds moving warm temperatures into central and northeastern SD. Temperatures will be between 10-20 degrees warmer than normal today and Wednesday, with highs in the upper 60s to mid 70s. There is a small shortwave aloft that will move along the contours of the ridge. This will push a weak low pressure and front through central and northeastern SD tonight and Wednesday morning. Luckily, there is drier air over SD, which will stop the front from developing precipitation. The only thing one would notice from the front moving through will be a change in the wind direction. As dry air sticks around today and on Wednesday, there will be sunny to mostly sunny skies.

Things will start to change Thursday, as an upper-level trough helps to push a surface low pressure from NV to the northeast over MT and then Saskatchewan. While this low pressure will not move over SD, it will have a couple of fronts that move over the state. Additionally, it will cause the pressure gradient to tighten over SD as the low pressure interacts with a strong high pressure over the Great Lakes. This tight pressure gradient will start to strengthen the winds aloft that will then mix down to the surface, causing strong southerly wind gusts to occur. The strongest of these wind gusts will occur Friday afternoon through Saturday morning. Ensembles show that there is a 30-50% chance for the winds to gust up to and over than 45 mph. These winds will need to be watched in upcoming model runs to see if a wind headline might be needed. These southerly winds will help to push more warm air into SD, which will increase the temperatures. The temperatures will be 15-25 degrees warmer than normal Thursday and Friday, with highs getting up into the 70s to low 80s. The warmest temperatures will be over south central SD, with a 40-60% chance that they get over 80 degrees.

The winds are not the only thing that will need to be watched in upcoming model runs. While this low pressure system will bring our next chance for rain, the models still vary the timing, track, and amounts. The models agree that the warm front for this low will be moving over SD Thursday and stay over the state into Friday. The models vary when and where rain and potentially storms start to develop along this front and how quickly the front (and its rain) moves out. The models then vary when the cold front moves in, when the rain might develop along it, as well as how long the front and rain stays over portions of northeastern SD Saturday into Sunday. There is still a 30-50% chance of precipitation occurring a some point Friday and at sometime on Saturday, there is just lower confidence on when and where.

Aviation

Issued at 1221 AM CDT Tue Oct 20 2026

Terminals KABR,KATY,KPIR,KMBG

Good VFR conditions are forecast throughout the TAF valid period.

Abr Watches

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