textproduct: Bismarck

KEY MESSAGES

- Dense fog will linger over portions of central North Dakota through the morning.

- Rest of today through Wednesday will see mainly dry and near normal conditions.

- Cooler temperatures possible later this week into the weekend. Some patchy frost could be found each morning.

UPDATE

Issued at 1028 AM CDT Tue Sep 29 2026

Have extended the fog advisory for a broad portion of north central into parts of south central North Dakota as visibility has been reluctant to improve. With that said, expect that by mid-day most locations should see notable improvement.

UPDATE Issued at 906 AM CDT Tue Sep 29 2026

Dense fog continues over much of the area, primarily over northwest/north central North Dakota into parts of the southwest. Elsewhere, visibility has really fluctuated through the morning, so will leave the Dense Fog Advisory in place through 10 am CDT. Otherwise, precipitation has exited our area so have removed all rain chances from the forecast.

UPDATE Issued at 638 AM CDT Tue Sep 29 2026

Showers with limited thunderstorms continue to push eastward, although have diminished a bit in intensity as they loose some of their convective attributes. Given these lessened rainfall rates have expired the Flood Watch and any Flood Advisories. There still could be pockets of localized flooding this morning. Behind these showers areas of dense fog continue to develop. Thus have expanded the Dense Fog Advisory to include most of central North Dakota through later this morning. Beyond this morning the forecast remains on track with mild temperatures, breezy west winds, and mainly dry conditions.

DISCUSSION

Issued at 400 AM CDT Tue Sep 29 2026

Upper level wave with a plume of moisture will continue to push eastward this morning. Meanwhile at the surface, a low pressure system and an associated stationary front will also slowly push eastward this morning. The result will be lingering showers and thunderstorms this morning, mainly east of Highway 83. With limited shear and instability, the main concern with these thunderstorms will be small hail and torrential rainfall. High Pwat values of an 1 to 1.5 inches will remain with this disturbance. Slow storm motion will also help with heavy rain this morning. Thus localized flooding is possible, especially to areas that have received abundant rain in the last 24 hours. Will maintain the current Flood Watch as thunderstorms move through. Clearing skies behind this front has brought areas of dense fog to northwestern and north central portions. Issued a Dense Fog Advisory as a result to areas already reporting fog. This may need to be expanded depending how quickly skies clear elsewhere. Otherwise, drying conditions will be found once rain moves out today. An increased zonal flow gradient aloft could bring some breezy westerly winds today. This combined with some lower RH values in the 20s could bring a brief period of elevated fire weather concerns this afternoon. Right now conditions do not appear to quick line up for critical fire weather concerns. Temperatures today could remain above normal with this warm and dry westerly flow, with highs in the 70s. Tonight, a weak cold front moves through while a dry southwest flow remains. Look for cooler lows in the mid 40s to mid 50s, yet mainly dry conditions. The steady wind and overall dry conditions should limit the fog threat tonight. This weak front continues to push through on Wednesday, perhaps continuing breezy northwest winds. Temperatures look to cool slightly with 60s in the north and 70s in the south. Mainly dry conditions are also expected for Wednesday. Surface ridge then enters the area Wednesday night into Thursday morning. This could bring cooler low temperatures in the mid 30s to mid 40s, and possibly some patchy frost.

Rest of the work week could then be influenced by this surface high bringing cooler temperatures and generally light winds. Mainly dry conditions are also expected, although perhaps a weak boundary brings a few showers in the southwest on Thursday. Patchy frost will be possible each morning with lows in the mid 30s to mid 40s. Highs may also be slightly below normal and in the 60s. Surface high moves eastward this weekend which could open the door for passing upper level disturbances. Moisture looks to be more limited for this weekend, thus PoPs are generally low. Temperatures also look to remain near to slightly below normal, which could provide patchy frost each morning.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 638 AM CDT Tue Sep 29 2026

Lingering morning showers and thunderstorms will be found in the James River Valley, including KJMS, this morning bringing MVFR to perhaps IFR conditions. Meanwhile, areas of dense fog will bring widespread IFR to LIFR this morning to much of northern and central North Dakota. Most sites have mention of either fog or showers until mid to late morning today. Conditions then look to improve to VFR later this morning or early this afternoon. VFR conditions should then remain through the remainder of the forecast period. Light and variable winds tonight will become a breezy westerly wind today then a steady southwest wind tonight.

BIS WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until noon CDT /11 AM MDT/ today for NDZ004- 005-012-013-019-020-022-023-056>058.