textproduct: Bismarck

KEY MESSAGES

- Rain gradually diminishes from southwest to northeast through the rest of today with seasonably cold temperatures.

- Near to below freezing overnight temperatures possible throughout the week.

- Near to below normal temperatures through the work week, then favored to warm above normal this weekend into early next week.

- Northwest winds may become strong on Thursday.

DISCUSSION

Issued at 201 PM CDT Mon Oct 12 2026

An upper-level shortwave continues to move from southwest to northeast across the region today which has been the focus for the widespread rain. An area of scattered thunderstorms also continues to slowly move across portions of the James River Valley and vicinity. While updrafts have struggled to become overly tall and wide with only around 500 J/kg of MUCAPE, deep layer shear has increased to around 50 knots or so in this area. Thus, lightning activity has become fairly frequent/widespread and a few individual cells have pulsed up to strong levels on occasion. Some small hail (possibly up to the size of nickels) will remain possible until storms move out by mid-afternoon. Highs this afternoon will be seasonably cold, only ranging from the lower 40s northeast to the low to mid 50s southeast.

Rain will gradually diminish from southwest to northeast through the rest of today as we become more zonal aloft. However, abundant clouds should stick around through the night which may limit how cold we dip tonight. The NBM continues to advertise a few below freezing values for lows tonight across the northwest and north central but this may be a little bit aggressive considering the overcast conditions. For now, will hold off on any freeze headlines. After a cool day Tuesday with highs in the upper 40s to mid 50s, we may have a better shot to see some more widespread subfreezing temperatures Tuesday night as clouds will be on the decrease. Freeze headlines may not be out of the question Tuesday night into Wednesday morning.

High pressure and progressive ridging settles in Wednesday as the pattern favors split flow with a closed low over the Four Corners region. This pattern will mean slightly warmer temperatures with NBM highs forecast to mainly be in the mid 50s to lower 60s. Cluster analysis then suggests that there is a high likelihood that the southwest cutoff low will kick out and phase with the northern stream towards the end of the week, but well east of our forecast area. Therefore, confidence is increasing that precipitation chances will mainly remain east, leaving most of North Dakota dry through the end of the week and into the weekend.

A dry cold front will move through the region on Thursday with strong high pressure on it's heels. Behind the front, models suggest some strong low-level cold air advection and pressure rises along with very steep low-level lapse rates. The latest NAM and GFS soundings suggest much of western and central North Dakota will see winds at the top of the mixed layer in the 40 to 50 knot range Thursday afternoon so it is looking more and more like a windy day with a potential need for eventual headlines. Depending on how much we dry out behind the front, there could be some fire weather concerns southwest as mentioned in the previous discussion. NBM guidance then suggests a warmup into the weekend with some highs back in the 70s possible by Saturday and Sunday.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1230 PM CDT Mon Oct 12 2026

Periods of rain will continue over the next few hours across much of western and central North Dakota. Thunderstorms may also continue for another hour or two across the south central and James River Valley, primarily impacting KJMS. Rain could reduce visibility to MVFR/IFR levels at times. Rain is expected to end from southwest to northeast this afternoon and evening.

Ceilings will primarily be IFR to LIFR through the forecast period. Northeast winds around 10 kts will turn to the northwest this afternoon and become lighter tonight. Some higher gusts are possible at times throughout the day. Ceilings may start to lift into MVFR categories Tuesday morning.

BIS WATCHES/WARNINGS/ADVISORIES

None.