textproduct: Bismarck

KEY MESSAGES

- Medium to high chances (40 to 70 percent) for showers and thunderstorms across the southern two thirds of North Dakota today. A few storms could be severe and produce locally heavy rainfall.

- Cooler but humid today, then becoming very hot again over the weekend.

- Hot, dry, and windy conditions on Sunday could result in at least near-critical fire weather conditions across much of the western half of the state.

DISCUSSION

Issued at 529 AM CDT Thu Jul 30 2026

A series of shortwave troughs is located at the top of a central CONUS ridge early this morning. Occasional showers and thunderstorms have been observed in North Dakota overnight, mainly in Hettinger and Grant Counties and along the Canadian border. A deeper shortwave ejecting off the Northern Rockies early this morning is forecast to to reach the Northern Plains this afternoon. The broad synoptic scale lift is expected to result in periods of showers and thunderstorms throughout the day, mainly across the southern two thirds of the state and with probabilities peaking in the afternoon. But CAMs continue to be highly inconsistent with timing and coverage of convection. More recent model initializations (after 00Z) have trended toward a much drier outcome until later this afternoon, but this doesn't seem to fit the conceptual model of modest differential cyclonic vorticity advection through a deeply moist air mass. It does appear there could be forcing assistance from weak upper level jet dynamics later this afternoon, which may be what 06Z and later guidance is honing in on. Whether convection later today remains elevated or becomes rooted in the near-surface or mixed layer could be strongly dependent on how cloud cover influences diurnal heating. But even if there is more sunshine than expected, updrafts may still need to overcome a capping layer aloft. CAPE is forecast to increase into the 1000-2000 J/kg range this afternoon, but could be higher if the RAP/NBM advertised dewpoints of upper 60s to mid 70s come to fruition. Shear at all layers is forecast to remain weak though, with effective bulk shear under 30 kts. The weaker shear with a lack of a well-defined surface boundary gives high confidence in a cluster storm mode with pulse intensity. A few stronger to marginally severe storms can still not be ruled out, but the threat ceiling should remain closer to baseline severe hazards of quarter size hail and wind gusts near 60 mph. It does appear there may be a conditional threat for non-supercell tornadoes, especially if the boundary layer is able to become unstable. The conditional aspect of this threat is that it would likely require outflow boundary collisions to generate the requisite surface vorticity needed for landspouts. This potential will not be messaged in any of our other products, but is something to keep in mind heading into the afternoon. Finally, there is still a risk for locally excessive rainfall from storms today, with anomalously high precipitable water, high deep-layer RH, and the potential for both training convection and slow storm motions. HREF guidance would indicate that a maximum rain amount of 2 to 4 inches is a reasonable high-end outcome, but the spatial coverage of even just +1" is likely to be very limited.

The shortwave responsible for today's convection is forecast to dig into the Upper Mississippi River Valley on Friday. A trailing, much lower-amplitude shortwave could bring a few showers or thunderstorms to western parts of the state throughout the day Friday, shifting into northern North Dakota Friday night when a low level jet could increase coverage. Higher CIN and lower CAPE should prevent severe storms on Friday, but if a storm can become rooted in the near- surface layer it would have access to as much as 40 kts of effective bulk shear. Forecast uncertainty paired with CAM reflectivity output precludes messaging of stronger convection at this time.

Today will be much cooler than yesterday, and likely the coolest day of the week for most with forecast highs generally in the 80s. There continues to be high confidence in the upstream upper level ridge re-amplifying and tilting back over the Northern Plains through the weekend. Most locations south of Highway 2 and west of Highway 83 are likely to see at least one day this weekend with a high temperature of at least 100 degrees. The triple-digit heat should remain confined to western parts of the state on Saturday, with spatial extent less certain on Sunday because of the timing of a cold front. Areas where the front passes through prior to peak heating (most likely far northwest North Dakota) could see highs closer to 90 on Sunday. But areas along and ahead of the cold Sunday afternoon (most likely southwest/central North Dakota) could easily reach or even exceed 105 degrees with the assistance of compressional heating. Not only could heat be an impact this weekend, but stronger winds on Sunday could combine with the hot temperatures and RH as low as 10-15 percent to produce at least near- critical fire weather conditions.

There is a low chance that showers and thunderstorms could develop along the cold front as it moves into central and eastern North Dakota later in the day Sunday into Sunday night, but stronger forcing aloft from a potent shortwave/upper low is projected to lag behind in Saskatchewan. A secondary surge of notably cooler air should begin pushing into the region on Monday as a separate shortwave swings from the Pacific Northwest toward the Northern Plains. Forecast high temperatures fall into the mid 70s northwest to mid and upper 80s south on Monday (which could be another windy day with fire weather concerns in the southwest), then to around 75 to 80 degrees for all of western and central North Dakota on Tuesday. Ensemble spread in synoptic scale features grows mid to late next week. Some clusters favor the western CONUS ridge rebuilding and shifting back eastward, while others transition to more of a zonal flow pattern over the Northern Plains.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 529 AM CDT Thu Jul 30 2026

Periods of showers and thunderstorms are likely through much of the forecast period. The highest probabilities are across southern North Dakota this afternoon. IFR visibility and gusty winds can be expected with heavier showers and storms. VFR conditions are otherwise likely to prevail. Variable wind direction this morning, becoming predominantly northeasterly by this evening, with speeds around 10 kts or less through the forecast period (outside of showers and storms).

BIS WATCHES/WARNINGS/ADVISORIES

None.