textproduct: Bismarck

KEY MESSAGES

- Well above average temperatures to be found this week, with near-record highs around 90 to 95 today and Tuesday. Breezy to windy expected conditions Tuesday through the end of the week.

- Dry weather today, with chances for showers and thunderstorms returning Tuesday night, followed by better chances for precipitation later this week.

- Dry and windy conditions could combine to bring near critical to critical fire weather conditions Tuesday through Friday, especially in far western North Dakota.

DISCUSSION

Issued at 227 PM CDT Mon May 25 2026

Ridge of high pressure aloft will remain across the state through tonight bringing dry and well above normal conditions. Winds will also trend on the light side through this evening, then become a steady southeast wind tonight as a surface low begins to form lee of the northern Rockies. Very low RH values will be found through this evening, although light winds will limit the fire weather threat. Lows tonight will be in the 50s with perhaps some lower 60s. CAMs have backed off on convection through tonight, as instability seems limited. Tuesday, upper level ridge gets compacted between two upper level lows. Meanwhile the mentioned surface low in the northern Rockies starts developing more. The result will be hot temperatures in the 90s across most areas, perhaps break some record highs. A breezy to windy southeast flow may also be found Tuesday. These increased winds combined with dry conditions could bring some near critical to critical fire weather conditions, especially in far western North Dakota. Here a Fire Weather Watch has been issued. For more details on these potential critical fire weather conditions see the Fire Weather Discussion below. Some near advisory winds are also possible in the west Tuesday, although the pressure gradient driven southeast flow may be tough to make strong winds thus will hold off on any wind products. There could also be a moderate to very isolated areas of high Heat Risk Tuesday afternoon. With dry air in place, the heat index will remain near to even below air temperatures. Thus will hold off on any heat products. Later Tuesday through Tuesday night, higher amounts of instability look to be found along a weak surface front associated with the developing surface low. This combined with influences from the low level jet could bring some isolated to scattered thunderstorms, especially in the north and east. Although instability is high, shear is modest at best. This combined with lack of a stronger lift mechanism should limit the severe weather potential. Steady east to southeast wind may linger through Tuesday night with lows in the 50s to lower 60s.

Wednesday through Friday, near critical to critical fire weather conditions could be found each day as hot, dry, and windy conditions persist through the week. Heat Risk will also remain moderate to isolated high Wednesday and Thursday with forecast highs in the 90s. Heat index values should still remain below advisory criteria. Surface low looks to linger in Montana through much of the week, which will continue near wind advisory southeast winds. Upper level ridge tries to reestablish mid week, which could limit chances for showers and thunderstorms. NBM currently keeps a mainly dry forecast although perhaps an isolated afternoon or evening thunderstorm is possible. Later in the week into the upcoming weekend the mentioned upper level ridge may shift slightly enough east to allow a broad western trough to influence the region more. This could slightly cool temperatures, bring daily chances for showers and thunderstorms, and continued breezy to windy conditions. RH values may improve slightly if this ridge shifts eastward, which could provide some relief to the fire weather threat in the west. This late week pattern does greatly depend on the influence of the mentioned ridge. Some clusters have it staying put instead of shifting. Which could continue mainly dry and warm conditions. Something to monitor throughout the upcoming week.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1237 PM CDT Mon May 25 2026

VFR conditions will prevail through the forecast period. Mainly dry conditions with upper level clouds are also expected. Light and somewhat variable winds today will become a southeast wind tonight. A breezy southeast wind is then expected for Tuesday.

FIRE WEATHER

Issued at 227 PM CDT Mon May 25 2026

Rest of today will see very warm temperatures in the mid 80s to mid 90s across the area along with very dry conditions. Expect afternoon and evening humidity values in the teens and 20s. Light winds are generally expected. Tonight, mainly dry conditions will persist with winds becoming a steady southeast wind. Humidity recoveries will generally be above 50 percent.

Tuesday, hot temperatures in the 90s will continue. This will bring low humidity values in the 20s west to the 30s east. A breezy to windy southeast wind is also expected to develop for Tuesday. This wind combined with low humidity values could bring near critical to critical fire weather conditions, especially to the far west. The main uncertainty with fire weather conditions this week are the status of fuels, especially after recent rainfalls. Current modeled Live Herbaceous Fuel Moisture showing values below 100 in the west, near 100 north, and generally above 120 elsewhere. This could indicate far western fuels are not fully green, with the north trending in the green direction, and greenup starting elsewhere. Another indicator can be (calendar) days since 0.5" of rainfall. Far western areas remain above 200 days especially in the northwest. Some north central areas are also above 200 days, although have higher Herbaceous Fuel Moisture values. Remaining areas have received a decent amount of rainfall in the past week. All things considered, decided to issue a Fire Weather Watch in the far western areas where confidence in greenup is lower. The other western and northern areas mentioned now have near critical wording in their HWO segments, and will need to be monitored closely.

Well above average temperatures look to continue through the week, along with a breezy to windy southeasterly wind. Afternoon humidity values could be in the 20s to 30s each day, improving only slightly to end the week. Depending on area fuels, near critical to critical fire weather conditions may be found each day mid to late week, especially in far western areas. Later in the day Tuesday though Tuesday night could see some isolated to scattered showers and thunderstorms especially in northern and eastern areas. Some increased chances for showers and thunderstorms may return later in the week, with mainly dry conditions to perhaps a few isolated thunderstorms expected in between.

BIS WATCHES/WARNINGS/ADVISORIES

Fire Weather Watch from Tuesday morning through Tuesday evening for NDZ001-009-017-031-032-040-043.