textproduct: Bismarck

KEY MESSAGES

- Showers and isolated thunderstorms will continue to diminish from west to east through tonight. - Mainly dry Saturday into early Sunday, with rain chances returning west to east late Sunday. Near daily low to medium (20 to 60 percent) chances for rain are then expected for the work week.

- Below average temperatures this weekend, followed by a brief warm up on Monday, then below average again through mid- week.

UPDATE

Issued at 1153 PM CDT Fri Aug 14 2026

Showers and isolated thunderstorms continue to taper from west to east across central and eastern ND. Precipitation has pretty much exited the west and low stratus and fog will continue to develop south and west across the areas as rainfall exits. No significant changes needed.

UPDATE Issued at 1032 PM CDT Fri Aug 14 2026

A narrow band of showers with infrequent lightning continues to track eastward through far south central North Dakota late this evening. For most of its existence, this convection has not been observed to be as strong as its radar reflectivity features would indicate, but just prior to this writing there was a 34 mph gust at an NDAWN site along the Grant/Sioux County border. The most likely outcome is that these heavier showers with occasional thunder will gradually decrease in intensity as they move into a more stable air mass over the next 1-3 hours. Analyzed effective bulk shear remains strong, but mid level lapse rates and DCAPE are very poor.

Rapid refresh guidance has shown an increase in the coverage of fog across northwest and north central North Dakota later tonight into Saturday morning. Visibility has already broadly fallen into the 2 to 5 mile range across this part of the state, with a couple of one half to one mile observations northwest of Minot. Confidence on how dense the fog may become remains low, as the processes driving the fog formation are neither clearly radiative nor advective.

UPDATE Issued at 739 PM CDT Fri Aug 14 2026

At 630 PM MDT, a broken line of low-topped thunderstorms extended from near Richardton to Hettinger. SPC mesoanalysis shows these storms to be in an environment with 1000-1500 J/kg CAPE and 30 kts of effective bulk shear. But they are also now moving into an area of increased CIN, and mid level lapse rates are mostly anchored to the moist adiabatic lapse rate. It therefore seems unlikely that the intensity of convection will increase beyond what has already been observed. Forecast adjustments for this update were driven by current observations and trends, but no major changes were made. Showers and thunderstorms should diminish from west to east through tonight. Did add a patchy fog mention to western parts of the state tonight into Saturday morning. This would mainly impact higher terrain areas where clouds could lower to the surface.

DISCUSSION

Issued at 218 PM CDT Fri Aug 14 2026

Current surface analysis places inverted trough over the western Dakotas, with high over eastern Manitoba into Ontario. Upper level analysis places high over the southern Mississippi Valley with ridge through the Midwest. To the west, trough noted over the west coast resulting in southwest flow over the Northern Plains. Over our area, broad area of rainfall continues over much of central and western North Dakota.

For the rest of this afternoon into this evening, broad area of rain previously mentioned will continue to gradually track towards the east-northeast. Towards the backside where rain had tapered off over southwest North Dakota, CAMs have been consistently showing some convection developing, some of which is showing up on radar over western South Dakota. Over our area, this is right in line with a narrow instability corridor advertised on the RAP of CAPE values pushing around 1500 J/Kg. So, cant rule out a stronger cell producing some small hail over this area, but believe the severe threat should remain limited.

As we go through the night precipitation will gradually exit the area. With the low level moisture in place there was some concern for fog developing over the west, but believe this should be limited by the expected north-northwesterly winds, but do expect low ceilings to develop and possibly a few patches of fog particularly in higher terrain.

Quieter weather expected over the area on Saturday as ridge starts to rebuild over the Rockies, though temperatures will remain on the cooler side of average. Flow remains west/northwesterly on Sunday, but a wave moving through the flow may produce some showers/storms late Sunday into the overnight hours.

Temperatures warm to near average for Monday before a strong short wave and affiliated cold front push into the area, which will bring cooler temperatures and medium chances (about 40 to 60 percent) for precipitation on Tuesday. Remainder of the work week looks to remain a bit active with occasional low chances for precipitation.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1153 PM CDT Fri Aug 14 2026

Showers continue across central North Dakota with a few thunderstorms south of KBIS, moving eastward. No VCTS will be needed at KBIS to begin the 06Z TAF period though. Heavy downpours could still reduce visibility to MVFR/IFR levels in the convection south of KBIS, but these should remain south of KBIS and KJMS. Rain should diminish from west to east through tonight.

Low ceilings are forecast to spread across much of western and central North Dakota into Saturday morning, with IFR and occasional LIFR over KXWA and KMOT. Fog may also reduce visibility to at least IFR levels tonight into Saturday morning, mainly across the northwest and north central. The low clouds and fog should lift and/or scatter by around late morning/early afternoon Saturday, with VFR conditions expected thereafter. Winds will become northwesterly around 10-15 kts on Saturday, with some higher gusts in the afternoon.

BIS WATCHES/WARNINGS/ADVISORIES

None.