textproduct: Bismarck

KEY MESSAGES

- Showers and thunderstorms returning this afternoon and evening. The threat for severe weather is low.

- Temperatures below normal today, with highs mostly in the mid 60s to lower 70s and lows in the 40s. Slightly warmer and generally dry for Friday.

- Near to slightly below seasonable temperatures, with daily chances for showers and thunderstorms, this weekend.

UPDATE

Issued at 652 AM CDT Thu Jun 18 2026

Limited updates needed this morning. Some patchy fog is showing up on satellite and webcams from about Baker, MT to the Bowman, ND area. Added in patchy fog through the mid morning hours in these areas. A very isolated shower has also formed in central ND, and may linger through the mid morning hours as well. Made some minor updates for this shower activity. Overall the forecast remains on track.

DISCUSSION

Issued at 345 AM CDT Thu Jun 18 2026

Northwest flow aloft will be found today, with a weak upper level wave moving through later this afternoon through tonight. Lingering moisture in this flow will bring pockets of clouds this morning through this afternoon with a steady northwest wind also expected. As mentioned a weak upper level wave moves through this afternoon and evening, which is expected to bring showers and thunderstorms from west to east during this time period, and possibly linger into tonight. SPC has general thunderstorm risk for today. There is some modest shear yet weak instability this afternoon and evening. Perhaps an isolated stronger storm is possible as a result, although skinny CAPE profiles should limit the hail threat, and the lack of DCAPE should limit the wind threat today. Temperatures today will be slightly warmer and generally near 70 degrees. Showers and thunderstorms will push eastward tonight, with cool overnight lows in the 40s expected. Varying levels of cloud cover can also be expected for tonight. If some areas can clear up then perhaps some patchy fog is possible, although not currently in the forecast. Northwest flow aloft looks to continue for the Juneteenth Holiday, Friday, while a surface high builds in the west. The result will be generally dry conditions for much of the CWA, except some eastern portions that could remain impacted by a large upper low aloft in southern Canada. This low may also bring enough of a pressure gradient for some breezy northwest winds across the area for Friday as well. High temperatures will be similar today and generally near 70 degrees.

This weekend, brief ridging moves through Saturday bringing mainly dry conditions to start. Some afternoon and evening showers and thunderstorms may be found in the west on Saturday as southwest flow aloft returns behind the mentioned ridge. Behind this ridge will also see a shift to east to southeast flow, which may become breezy in the west on Saturday. A more unsettled pattern is then expected for Sunday with a broad trough pattern, and nearby surface lows. Increasing moisture from a southerly flow is also expected, especially across the west. This could lead to morning showers and thunderstorms across the west, and perhaps some patchy fog. Upper level wave then moves across the region through the remainder of Sunday, while a secondary low moves to our south. This is forecast to bring increased chances for showers and thunderstorms, with a continued breezy east to southeasterly flow. Temperatures may also cool slightly for Sunday. The better instability looks to remain to our south this weekend, limiting the severe weather threat. This broad upper level trough could continue to linger across the region Monday, bringing similar conditions with slightly below normal temperatures and lingering chances for showers and thunderstorms. Tuesday through Wednesday next week still have moderate to high confidence in warming temperatures as a ridge is forecast to build to the west. Placement of this ridge will impact precipitation chances, with current guidance still providing slight to chance PoPs given some embedded waves in northwest flow aloft that may linger.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 652 AM CDT Thu Jun 18 2026

Mainly VFR conditions are expected through the forecast period, with some low VFR cloud ceilings at times. Patchy fog is possible in the far southwest this morning, although is not expected to impact any TAF sites. Another round of showers and thunderstorms may return from west to east this afternoon through this evening. Most sites now have prevailing or PROB30 groups to account for this precipitation potential. Some brief MVFR conditions are possible with these showers or thunderstorms. Look for steady westerly wind through the TAF period.

BIS WATCHES/WARNINGS/ADVISORIES

None.