textproduct: Bismarck

KEY MESSAGES

- Medium to high chances for showers today through tonight.

- A few thunderstorms are possible this afternoon into tonight, with an isolated strong to marginally severe storm possible far southwest and south central.

- Mainly dry and warmer Tuesday and Wednesday.

- Wide range in temperatures from northwest to southeast Thursday as a cold front pushes into the State. - Significant cool down for the end of this week, with medium chances for both rain and snow.

UPDATE

Issued at 1129 AM CDT Mon Apr 13 2026

Midday update mainly for pops. An east to west area of showers with a few lightning strikes lifting north along the I-94 corridor, with another area of showers in the far north. Short term models are having a hard time picking up on this so mainly a hand drawn area of pops through the early afternoon. Cams are a little more consistent later this afternoon through tonight with the main wave lifting through bringing another round of showers and maybe a few thunderstorms. An isolated strong to possibly severe storm can not be completely ruled out late this afternoon through this evening in the far south, probabilities look to be quite low. SPC has limited the Marginal Severe threat to only the far southern tier counties with their update late this morning.

UPDATE Issued at 857 AM CDT Mon Apr 13 2026

For the morning update we lowered high temperatures, mainly along and south of I-94. Widespread stratus looks like it will remain through the day (also bumped up sky cover) across most if not all of western and central ND. We also adjusted pops just a little. Will continue with mainly chance pops this morning lifting north and east. There have been some light rain showers with the reflectivities lifting north along the I-94 corridor. There is some general upper level ridging, especially this morning and the 12Z Bismarck sounding showed quite a bit of dry air remaining, so qpf with any shower activity this morning is expected to be minimal. Then the south dries out a bit this afternoon, with higher pops lingering in the north. Better chances with the main wave lifting through the area later today and tonight. We also extended the mention of fog through the morning. Updated text products will be transmitted shortly.

UPDATE Issued at 652 AM CDT Mon Apr 13 2026

A line of showers continues to move from southwest to northeast through across North Dakota at the time of this mid morning update. These showers have been a little less pervasive then suggested by the CAMs, with the 12Z sounding here at the office suggesting a layer of relatively drier air helping to limit how much precipitation is reaching the ground. Short term deterministic models continue to advocate these layer saturating through the mid morning, especially as secondary wave already promoting the development of showers in Montana moves into the west. For the showers that we do have this morning, areas of fog have been observed to develop as they move off to the northeast, with visibilities across portions of the far southwest dropping as low as 1/4 SM at times. Jumping around ND DOT cameras across this are suggest this denser fog is somewhat limited in areal extent, and the expectation is that visibilities should improve through the mid morning as surface winds begin to pick up. Considering the morning commute, we have opted to issue a SPS across much of the southwest due to the potential for rapidly changing visibility.

DISCUSSION

Issued at 400 AM CDT Mon Apr 13 2026

Southwesterly flow is found across the northern Plains this morning as a Pacific trough over the western CONUS is progged to split and be absorbed into the northern stream through the day today. With this moving across the region as a shortwave perturbation, medium to high chances (40 to 70 percent) for precpitation are expected across much of the forecast area this morning through late tonight. While mainly falling as rain, cooling temperatures tonight into Tuesday could allow for a little snow to mix in with the rain across portions of north central North Dakota, though no snow accumulation is expected. With how pervasive this precpitation will be through this period, much of the forecast area has medium chances (40 to 60 percent) to exceed 0.25" of QPF through Tuesday morning, with a low chance (10 to 30 percent) to exceed 0.50". It's starting to get to the point of the year where we must consider the convective environment as well. With seasonable warm weather lingering across the south today, with highs from the mid 40s north up to the upper 50s and lower 60s south, short term deterministic guidance continues to advertise modest instability becoming available by the mid to late afternoon across portions of the southwest and south central, with model MUCAPE values approaching 500 J/KG. That being said, an interrogation of BUFKIT model soundings during this periods reveals a fairly robust cap across much of the south through the afternoon, so we may struggle to see much more than elevated thunder during this period. That being said, there is a low probability scenario where the early erosion of this cap could allow for a stronger storm to develop, considering the ample of amount of BULK shear advertised by the CAMs around this time (approx 35 to 40 knots). If this scenario does pan out, small hail and an isolated, marginally severe wind gusts up to 60 MPH would be possible. SPC as placed southwestern and south central North Dakota into a level 1 of 5 risk for isolated severe thunderstorms for this afternoon into this evening.

Mainly dry conditions are then expected Tuesday and Wednesday as near zonal to slightly southwesterly flow is established above the forecast area. A transient shortwave is progged to pass through the region Tuesday afternoon through Wednesday, promoting another round of light rainfall, though there is fairly strong agreement between ensemble members on this remaining to the south of North Dakota at this time. With the near zonal flow persisting through the mid week, warming highs from the 50s and 60s on Tuesday to the 60s and 70s on Wednesday are expected.

A transition back to southwesterly flow is then anticipated late Wednesday into Thursday as a strong upper level low makes landfall in the Pacific Northwest. Chances for precpitation (40 to 60 percent) increase through the day Thursday as a surface low complex moves out of the southern Canadian Prairies and approaches western and central North Dakota. While initially falling as rain through the day Thursday, with lingering highs broadly in the lower 50s northwest to mid 70s southeast, a sharp transition to all snow is expected to occur Thursday night into Friday as a cold front associated with this drops across the area. With this, at least light accumulations of snow can be expected across much of the forecast area, with the NBM advertising a light dusting across the south up to an inch or two along the International Border. Cluster analysis reveals this to the majority solution, with around 55 percent of members favoring a northerly track to the low complex. A minority cluster also exists (45 percent of ensemble members), which has a slightly stronger low complex dipping further to the south than what is advertised by the NBM, allowing for a quicker transition to all snow across the south overnight into Friday. With this scenario, accumulations up to an inch would be possible as far south as Interstate 94. In either scenario, breezy to windy conditions can be expected Thursday and Friday as and pressure gradient sharpens, and CAA increases along and behind the cold front. That being said, the upper end of these winds may be only near to marginally wind advisory criteria due to the timing of the frontal passage and the lack of a strong 850-700mb jet during this period. This thinking seems to fall in line with the lack of any anomalous wind signal in the most recent ECMWF EFI, though we will need to continue monitoring this period moving forward. After the much cooler weather on Friday, there is decent agreement in the ensemble on warming temperatures by the end of the weekend into early next week as longwave ridging builds in behind the trough, though there is some modest disagreement on the timing of this transition back toward warmer weather.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1129 AM CDT Mon Apr 13 2026

Expect widespread IFR to LIFR ceilings across western and central ND through tonight. There will be times this afternoon and evening when some MVFR ceilings may be found, but overall, expect low stratus to remain through much of the night. Do expect some improvement in ceiling from west to east Tuesday morning. Isolated to scattered showers and thunderstorms are possible central and south, then mostly in the south tonight. Any thunderstorms will have the capability of producing gusty and erratic winds with low vsbys in heavy downpours. Expect an easterly surface flow today and tonight 5 to 15 Kts, turning south to southwest 5 to 15 Kts on Tuesday.

BIS WATCHES/WARNINGS/ADVISORIES

None.