textproduct: Bismarck

KEY MESSAGES

- Hot conditions will continue through at least the middle of the week, with highs mostly around 90 to 100.

- Smoke from distant wildfires will continue to make the sky hazy and reduce surface visibility early this week.

- An isolated strong to severe thunderstorm could enter far southwest North Dakota this afternoon and early evening, with the main hazard being wind gusts up to 60 mph.

- Medium to high chances (30 to 70 percent) for showers and thunderstorms Wednesday afternoon through Thursday. A few storms could be severe in western North Dakota Wednesday afternoon and evening.

DISCUSSION

Issued at 115 PM CDT Mon Jul 27 2026

Currently, scattered thunderstorms remain just north of the International Border, in northwest and north central ND, but do extend south as you get to the Turtle Mountains area. Elsewhere, Isolated showers and thunderstorms were located over eastern Montana.

For this afternoon and tonight, there is some elevated instability across northern and western portions of the forecast area. There is a marginal risk (level 1 out of 5) of severe storms over the far southwest (mainly Bowman and Adams Counties). Surface low pressure over southeast Montana is forecast to move into southwest ND later this afternoon. Southwest ND will be in an area of surface convergence ahead of the low. There is on the order of 500-1000 J/kg of elevated CAPE above an area of good CIN. The far southwest looks to be the one area in the west which could see most of the CIN erode later this afternoon into early evening. Every so often one of the CAMs will show a few stronger cells over the far southwest. A combination of the decreased CIN and surface convergence could support a strong to severe storms with the main threat being wind gusts to 60 mph. In the north convection continues along the International Border. Instability does increase with good shear as you move east across the north central. The SPC mesoanalysis page indicated increasing CIN over both western and northern ND later this afternoon into this evening. Therefore, the overall threat for severe storms looks to remain low.

Tonight CAMs do show scattered shower/thunderstorm activity spreading west to east over the southwest and south central, along with scattered convection along the north spreading south and east. Really uncertain about overall coverage of any activity tonight given the general strong capping, so stuck more to a broadbrush of slight chance pops through tonight.

Elevated smoke looks to remain over the area for the next few days, so kept a mention of smoke in the forecast and put a lower limit on the sky cover through Tuesday.

Temperatures climb higher Tuesday and Wednesday. Tuesday looks to be mostly dry with upper level ridging building over the area. The lack of low level moisture should also keep heat index values below critical values, even as surface temperatures climb into the upper 90s south and west of the Missouri River. On Wednesday, temperatures are about the same as or a little higher than Tuesday. A southerly return flow should also bump up dew point temperatures a little. This could bump apparent temperatures high enough for a Heat Advisory. However, the uncertainty is high enough at this time to give it another day. Currently it appears that it would probably be a limited area and for a limited duration so would most likely pass if we were needing to make a decision today.

Wednesday night and Thursday we see a series of waves propagating through the mean upper ridge, bringing us better chances for showers and thunderstorms than we have seen in a while. Right now things look a bit messy with perhaps a southern stream and a northern stream wave traversing the forecast area with a lot of uncertainty in timing and placement of said waves and resulting convection. NBM continues with it's broadbrush area of medium to high pops Wednesday night and Thursday. As was mentioned yesterday, not overly excited about the areal extent of high pops but this far out. a broadbrush approach seems justified.

Temperatures do drop a little after Wednesday, with highs mainly in the mid 80s to mid 90s Thursday and Friday, followed by a warm-up as we head into the weekend.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 1141 AM CDT Mon Jul 27 2026

Generally VFR conditions are expected through the 18Z TAF period. With smoke lingering, later tonight into Tuesday morning could see periods of MVFR visibilities, but will keep P6SM for now. Mainly isolated shower and thunderstorm activity this afternoon and this evening and will not include a mention at any TAF site attim, but any storms could produce gusty and erratic winds. Light and variable winds expected through the TAF period remaining at or below 12 knots through the period.

BIS WATCHES/WARNINGS/ADVISORIES

None.