textproduct: Bismarck

KEY MESSAGES

- Areas of dense fog expected to return to northwest and central North Dakota tonight, lasting into Monday morning.

- Above normal temperatures through the middle of the week, with a continued large spread from northeast (colder) to southwest (warmer).

- Mostly dry weather this coming work week, with a low chance (10 to 20 percent) of a light wintry mix across southern North Dakota late Monday into Tuesday.

UPDATE

Issued at 109 AM CST Mon Jan 5 2026

The main update with this product issuance was to sky cover, to better reflect latest satellite imagery and trends. No changes to the Dense Fog Advisory, and will continue to monitor.

UPDATE Issued at 952 PM CST Sun Jan 4 2026

Only change for this update was to expand the Dense Fog Advisory into McHenry, Wells, Foster, Stutsman, and LaMoure Counties. Dense fog has been observed at times at Estevan over the last couple hours, and was recently seen trying to settle in on a webcam near Portal. But this particular area of fog still seems highly localized at this time.

UPDATE Issued at 632 PM CST Sun Jan 4 2026

We have allowed the Winter Weather Advisory to expire. All locations south of Highway 200 are now reporting visibility greater than 6 miles, indicating a very low probability in the presence of freezing drizzle. North of Highway 2 though, visibility has consistently been one half mile or less from Bottineau to Rolla to Towner. There is very little, if any evidence in forecast guidance to support any improvement in visibility, and most guidance would suggest an areal expansion of dense fog through this evening across much of northern and central North Dakota. We have therefore issued a Dense Fog Advisory through Monday morning. For now just kept it to where dense fog is already observed in (eastern) Bottineau, Rolette, and (northern) Pierce Counties. Do anticipate needing to expand it later on, but want to wait for increased confidence in dense fog vs. low stratus with mist. RAP forecast soundings also show a lingering potential for freezing drizzle from the Turtle Mountains to the northern James River Valley through this evening and into the overnight hours, but think that low visibility should remain the primary hazard.

UPDATE Issued at 457 PM CST Sun Jan 4 2026

Quick update to remove McHenry and Sheridan Counties from the Winter Weather Advisory. The rest of the advisory remains set to expire at 6 PM CST, but it is beginning to look likely that we will need at least a Dense Fog Advisory in the Turtle Mountains area this evening, with further expansion possible through tonight.

DISCUSSION

Issued at 255 PM CST Sun Jan 4 2026

Upper level wave with a trailing warm front will continue to push eastward through this afternoon and evening. Along this wave and ahead of the warm front will continue to be pockets of freezing drizzle or brief freezing rain. NDDOT webcams and road reports showing this is still ongoing thus will keep the Winter Weather Advisory as is through this afternoon. Visibilities from fog have improved for most areas, although patchy dense fog remains in some northern areas. Will let the Dense Fog Advisory expire on time at 3 PM CT, while adding mention of lingering fog in the Winter Weather Advisory. A sharp clearing line will also work eastward, yet is expected to stall this evening across central portions. Tonight, light winds and moist low levels will provide for another foggy night, with much of the north, central, and east expected to see fog return. Most hi-res models have this as dense fog, although confidence was not high enough to reissue an advisory at this time. Will let later shifts monitor trends and issue any needed products. Of note are the lack of dense fog forecast in the southwest, possibly from warm temperatures and slightly drier air. Lows tonight will be in the teens northeast to the 20s southwest. Any fog that forms is expected to mostly diminish Monday morning, although may linger in the east. Zonal pattern aloft will be found on Monday. This is currently forecast to be mainly dry, although a weak wave will move in the flow to our south. This could bring at least a slight chance of a wintry mix south of Interstate 94 on Monday, yet confidence was not high enough to include in the forecast at this time. Highs on Monday will continue to be mild and generally in the 20s and 30s, with 40s southwest. Dry westerly flow could then be found Monday night, perhaps ending the fog threat. Lows Monday night could be cooler and in the single digits north to the 20s south.

Zonal flow pattern then sets up through at least mid week. This could continue mild temperatures and mainly dry conditions. There still could be a stark temperature contrast with highs in the 20s northeast to the 40s southwest through mid week. Low temperatures will be more broad with lows in the teens north to the 20s south. Another weak wave may clip the south on Tuesday, perhaps bringing some more wintry mix chances. Although currently the NBM has 10% or less in the forecast. Some breezy westerly winds may be found on Wednesday ahead of a weak cold front. Clusters showing a broad trough pattern returning to the region to end the week. A surface low may kick out into the southern plains as a result, although about 70% of ensemble members keeps this low too far south to impact North Dakota. The remaining solutions clips some southern portions of the state with snow chances yet still keeps the more impactful snow generally out of the CWA. Overall NBM has a mainly dry forecast at this time although will warrant monitoring the progression of this next trough. This trough pattern could return northwest flow and bring cooler more normal like temperatures to the area. Some breezy winds may also return in northwest flow, although the signal for strong winds is currently not present.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 109 AM CST Mon Jan 5 2026

LIFR ceilings and areas of dense fog are expected to prevail across the eastern half of the state through Monday morning. The low clouds and fog are also likely to fill back in across parts of northern North Dakota. Confidence in LIFR conditions is high at KMOT, but lower from KXWA to KBIS.

The low ceilings and fog are forecast to erode from west to east during the day Monday. Confidence in visibility improving to at least MVFR levels from KMOT to KJMS is high, but IFR ceilings are likely to remain over KJMS through the afternoon, and may barely clear KMOT. North central and eastern parts of the state, including KMOT and KJMS, are once again expected to fall under low stratus and fog Monday evening.

Southwest North Dakota should remain at VFR conditions through the forecast period. Light and variable winds at all terminals through tonight, then westerly near 10 kts in western North Dakota Monday afternoon while remaining light and variable through central North Dakota.

BIS WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until noon CST today for NDZ004-005-012-013- 023-025-037-048.