textproduct: Bismarck

KEY MESSAGES

- Highs today warm to above normal, with highs in the mid 60s to mid 70s.

- Temperatures will continue to average well above normal both Tuesday and Wednesday, along with mainly dry weather conditions.

- Active weather pattern is favored Wednesday night through the end of the week, with medium to high precipitation chances along with a strong cooling trend.

UPDATE

Issued at 939 AM CDT Mon Apr 20 2026

Surface trough is analyzed from west central Manitoba back to eastern Montana, with winds becoming more northwesterly on the west side of the boundary. A few high clouds are drifting through but should be a pleasant spring day, especially as winds lessen a bit through the day. No changes needed with this update.

UPDATE Issued at 612 AM CDT Mon Apr 20 2026

No changes outside of sky cover and hourly weather elements. For latest forecast discussion see below.

DISCUSSION

Issued at 430 AM CDT Mon Apr 20 2026

Currently, west-northwest flow aloft over the region with an upstream embedded impulse over southern Alberta and an associated and subtle surface low/trough over southern Saskatchewan stretching south across eastern Montana. A mostly clear sky at the moment with upper level clouds streaming southeasterly aloft. With WAA ongoing, temperatures this morning much more moderate compared to the previous few mornings, with temperatures currently ranging in the upper 20s to upper 30s over west/central ND (compared to teens and 20s previously).

Embedded impulse and subtle sfc low push across the Northern Plains today, dragging a weak cold front southward across western and central North Dakota this morning and afternoon. Main result will be a wind shift from south to west and eventually to northwest. Outside of the James River Valley, winds remain relatively light, sustained up to 15 mph or so. Across the James, gusty southerly winds, currently over some locations now, continue through early/mid afternoon before decreasing. Fairy dry this afternoon, with forecast highs in the mid 60s to mid 70s coupled with dewpoint temps in the 30s, resulting in forecast Min RH values in the 20s most areas, with some teens southwest. Opted to maintain a mention of near critical fire weather in the southeast, and will also mention in the southwest in case our winds overperform there (still have a wind shift regardless).

Flow aloft will gradually transition to more quasi-zonal into Tuesday, continuing the warming trend and maintaining a dry weather forecast. Warmest day this week will be on Wednesday, when broad ridging amplifies over the Northern Plains ahead of a strong upper level trough developing into the western CONUS. Ahead of this trough, a lee side surface low strengthens, and results in strong southerly flow and WAA across the Dakotas. High temperatures into the low/mid 80s across the south are forecast, with 70s elsewhere. Increasing boundary layer moisture under this flow pattern as well, resulting in unseasonably high MUCAPE across the eastern half of the state to around 1K J/KG during the day. South-southwest flow aloft develops and increases Wed aft into Wed night, with shower and thunderstorm chances increases over the Dakotas, with the better chances likely near the sfc trough axis over the east. SPC predictably has us in the general t-storm outlook for Day3 (Wed/Wed night).

The base of the western CONUS trough is still favored to lift northeast into the Northern Plains and morph into a closed low on Thursday, followed by another northern stream closed low developing into our region Friday and Saturday. Periods with the highest POPs are Thu-Fri, with more uncertainty into the weekend (depending on the position of the upper low...how far north or south). Thus an active and cooler weather pattern will end the work week and continue into the weekend, with high temperatures in the 30s and 40s forecast Fri-Sun, and lows in the 20s. We still expect rain changing to a mix and eventually all snow Thursday night-Friday AM as colder air is pulled south into North Dakota with the initial low. Still too early to dive into details with this dynamic period, but NBM is trending higher with snow totals but still nothing ridiculous. As the lows wind up, strong winds are also forecast both Thursday and Friday, and will also likely linger into Saturday. Will keep a mention of this in the HWO.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 612 AM CDT Mon Apr 20 2026

VFR conditions are expected through the 12Z forecast period. Some high level clouds will stream aloft at times, along with SKC conditions as well. Southerly winds will become west followed by northwest through today and this evening as a front moves southeast across the region. Low level wind shear will be present central and east through around 15Z this morning.

BIS WATCHES/WARNINGS/ADVISORIES

None.