textproduct: Bismarck

KEY MESSAGES

- Well above average temperatures through the rest of the work week, with highs in the 40s and 50s in the Turtle Mountains area, and upper 50s to lower 70s across the rest of western and central North Dakota.

- Fog may develop tonight, especially for areas along and east of Highway 83.

- Mostly dry conditions through the rest of the workweek, with low chances for precipitation returning over the weekend.

- Cooler temperatures return Sunday and continue into next week.

DISCUSSION

Issued at 245 PM CDT Wed Mar 18 2026

This afternoon, broadly cyclonic flow was in place over the Northern Plains upstream of troughing over the eastern CONUS, while a dome of high pressure was developing over the southwest CONUS and raising heights over the Northern Rockies. Temperatures have been warming up nicely as a warm front moves through the region, with widespread 50s and 60s, with the exception of the far north central. We are carrying a slight chance of precipitation across the north central this evening as an embedded wave drifts through, although recent CAMs runs have backed off on this potential. Could be a wintry mix depending on timing, but with overall low probability not expecting much impact from this.

Main forecast concern tonight is for fog potential central and east, with winds dropping off and an abundance of low level moisture from continued snowmelt. Main question is how far west does fog extend but did expand patchy fog mention to include the Highway 83 and Bismarck/Mandan corridor, but certainly more confidence further to the east, especially in the James River Valley.

Very mild temperatures continue on Thursday as low-level warm air advection persists, with temperatures likely peaking this day although the warmer temperatures continue into Friday. Current forecast highs has upper 60s to lower 70s for areas along, south, and west of the Missouri River, with potentially record-breaking highs at Dickinson (71), Bismarck (70), and Williston (70). Much cooler temperatures persist in the Turtle Mountains area.

We did opt to blend down forecast dew points on Thursday with some high-res model guidance, which lowered minimum relative humidity into the 20 percent range across far southwest North Dakota. This, combined with breezy west winds (and a tendency to overperform temperatures and overmix), prompted the mention of near critical fire weather conditions in Slope, Bowman, Hettinger, and Adams Counties, although this will likely be a brief period.

The pleasant weather continues into Friday as the upper ridge axis tries to slide over but also flattens, with similar highs to Thursday. Blended guidance then starts to bring in low chances for precipitation as ensemble members support a more pronounced shortwave moving through sometime this weekend. There is still a moderate amount of spread in forecast high temperatures on Saturday, with a significant skew towards the cold side, as ensemble guidance differs on when a cold front will move through the state. Right now clusters are split generally 50/50 on an early in the day vs late in the day solution, with the deterministic NBM favoring the late day scenario, keeping warmer temperatures in place longer. Blended POPs have also increased some with the latest NBM run, although are still only generally 20 to 35 percent, and peak Saturday night.

Consensus in the forecast increases on Sunday, with high confidence in maximum temperatures being back in the 30s and 40s. Flow is favored to be a little more active next week, with up and down temperatures and potentially some additional chances for light precipitation.

A steady breeze is expected most days Thursday through Monday, although at this time we are not expecting any high impact wind days, a thought echoed by no significant highlights in the latest ECMWF EFI output. The CPC 8-14 Day Hazard Outlook does highlight a moderate risk of high winds for the middle of next week across western North Dakota, with a frontal passage bringing cooler temperatures for the end of the week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1225 PM CDT Wed Mar 18 2026

VFR conditions expected for the majority of the TAF period. Currently some high clouds moving through the area with winds shifting more westerly and becoming breezy as a front moves through. Winds become light and variable tonight, with patchy fog possible across parts of north central North Dakota and the James River Valley. Did include lower ceilings and vsbys at KJMS/KMOT with this update, but low confidence on how widespread and dense fog will end up. Conditions at these terminals improve late in the period with breezy west winds developing Thursday morning.

BIS WATCHES/WARNINGS/ADVISORIES

None.