textproduct: Bismarck

KEY MESSAGES

- Areas of frost this morning across northwestern and north central portions. Low temperatures are then forecast in the 30s across the north tonight, and across much of the state Sunday night through mid week.

- Near critical fire weather conditions are expected over portions of southwestern and south central North Dakota this afternoon into this evening.

- High chances (60 to 80 percent) for showers and a few thunderstorms tonight through Monday night. The highest chances are during the day Sunday and Monday afternoon through Monday night.

- Isolated severe thunderstorms are possible in the southern James River Valley Sunday.

DISCUSSION

Issued at 409 AM CDT Sat May 16 2026

A weak and mainly dry cold front is moving across the north this morning bringing some lower clouds and cooler temperatures. These cooler temperatures could result in some frost in the northwest and portions of the north central. Observations also showing these cooler temperatures entering into McKenzie county. Thus have expanded the Frost Advisory into this county, while keeping the remaining areas as is. Meanwhile a jet streak is bringing some mid level clouds and weak radar returns across the south this morning. As this jet streak moves across the state some sprinkles are possible in the southern half this morning. A brief upper level ridge then moves in for today bringing mild high temperatures in the 70s and mainly dry conditions to the area, although areas in the north may see more normal like temperatures in the 60s with the passage of this morning's cold front. A developing surface low lee of the northern Rockies will switch winds to the east southeast, and may become breezy across southern portions by mid to late afternoon. This combined with low RH in the 20s could bring some near critical fire weather conditions to southwestern and south central portions. Tonight, surface low and upper level trough will begin to move eastward and into the state. The result will be increasing chances for showers and thunderstorms from west to east through the night, although dry air in place may delay showers until the overnight hours. Lows tonight will generally be in the mid 30s to mid 40s. The increasing clouds and precipitation chances should limit the frost threat for tonight. Breezy southeast winds may also continue through tonight.

The mentioned low pressure system then moves through Sunday. With this will bring widespread shower and thunderstorm chances across the state. Northern, central, and eastern portions still look to have higher chances as the southwest may experience some dry slotting. Overall NBM has a 50 to 80% chance of at least a half of an inch of QPF Sunday in the mentioned favored areas, with chances for at least an inch slightly lowered. SPC has also clipped southeastern portions of the CWA with a Marginal Risk for severe weather on Sunday. The window for severe weather will be limited and generally Sunday afternoon when instability is at its peak. Shear will be abundant, however instability will be modest. The shear vector may also not favor discrete cells with this set up. However, if a stronger storm can develop hodographs and high shear environment could produce some large hail and damaging wind gusts. Temperatures will be much cooler on Sunday with highs in the 40s north to the 50s to lower 60s south. Breezy east northeast winds are also expected. A lull in showers and thunderstorms could then be found Sunday night, although abundant low level moisture could lead to some low clouds and drizzle through the night. Lows will generally be in the 30s. Another trough could then bring more showers and perhaps a few thunderstorms Monday afternoon through Monday night. Cool temperatures will remain on Monday with highs forecast in the mid 40s to mid 50s. NBM chances for 0.50 inches or high of QPF for Monday through Monday night are lower than Sunday and generally 10 to 40 percent. The chances for snow Sunday night and again Monday night remain low although continue to be found. This will greatly depend on precipitation timing, location, and overall temperatures. Right now NBM has low chances for snow in the northwest Monday morning, and low to medium chances for snow in the southwest Monday night into Tuesday morning. Something to monitor as low temperatures Monday night remain in the 30s.

The mentioned trough then moves east for Tuesday diminishing shower chances yet keeping cool temperatures in the 40s and 50s. Breezy north winds may also be found especially in central and eastern portions. High pressure moving through under northwest flow Tuesday night into Wednesday will bring colder lows in the upper 20s to upper 30s. This could result in widespread frost for the area, and perhaps some areas of freeze. Mid to late next week then sees a warming trend under northwest flow aloft with southerly flow at the surface from the exiting high pressure system. Weak instability combined with weak disturbances in the northwest flow could bring isolated shower and thunderstorm chances each day. Low temperatures look to improve through next week as do high temperatures. NBM spreads showing by late next week high temperatures could return into the 70s.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1244 AM CDT Sat May 16 2026

VFR conditions to be found through the forecast. Light westerly winds are expected tonight into Saturday morning, with some passing high clouds at times. Late morning through the afternoon Saturday, light winds will become a steady northerly then easterly wind. A breezy easterly wind may then develop across most sites Saturday evening through the night. VFR and mainly dry conditions will remain for Saturday, with some mid to high level clouds at times.

BIS WATCHES/WARNINGS/ADVISORIES

Frost Advisory until 9 AM CDT /8 AM MDT/ this morning for NDZ001>003-009-010-017-055.