486 FXUS63 KBIS 220737 AFDBISArea Forecast Discussion National Weather Service Bismarck ND 237 AM CDT Mon Sep 22 2025
.KEY MESSAGES...
- Patchy fog possible til mid-morning.
- Above average temperatures and dry conditions through the week.
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.DISCUSSION... Issued at 237 AM CDT Mon Sep 22 2025
Model guidance remains bearish in regard to impactful fog formation this morning. RAP model forecast soundings are having a difficult time saturating near the surface, while HRRR forecast soundings barely do so, and even then, and mainly for the James River Valley and far southwest. That said, with light and variable winds, along with clear skies, a good radiational cooling set-up is present. As such, patchy radiational fog will probably develop closer to sunrise for at least some of the area. Most of this fog will likely be shallow and confined mostly to fields and low-lying areas. Should any thicker fog develop, the most favored areas would be in the aforementioned James River Valley or the far southwest.
Once any fog clears out this morning, expect mostly sunny skies and light winds today. The exception is western ND where weak troughing may bring a few clouds, along with breezy winds as the surface pressure gradient tightens. For tonight, mostly clear skies are expected, although with steady light northwesterly winds and lower dewpoints progged; fog development seems unlikely, especially for western ND. Should any fog development occur, it would most likely be in the James River Valley where dewpoints remain a bit higher and winds more light and variable through the night.
All in all, the forecast for this week is very quiet. A weak ridging pattern looks to prevail through most of the workweek resulting in above average, yet fairly steady high temperatures in the 70s at most locations, most days, with a few readings in the low 80s. Similarly, lows will be mostly in the upper 40s to low 50s. Though with light winds and often clear skies forecast, wouldn`t be surprised if lows don`t wind up a bit cooler at times. Models are also in fair agreement that a trough will pass through at the end of the week and into this weekend. At this time, the main "impact" would be temperatures closer to average.
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.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1229 AM CDT Mon Sep 22 2025
Patchy fog may develop again tonight and into Tuesday morning. However, model signals aren`t the strongest and any saturation seems near the surface. So for the most part, if fog does develop, most likely it will be shallow radiational/field fog. The main areas models hint at developing a bit thicker fog is in the far southwest and the James River Valley. As such, used VCFG at KJMS tonight and into early Tuesday morning, otherwise left fog mentions out of TAFs. Other than any potential fog development, VFR ceilings and visibility are expected through the period.
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.BIS WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION...Telken AVIATION...Telken
NWS BIS Office Area Forecast Discussion