FXUS63 KBIS 201904

AFDBIS



Area Forecast Discussion

National Weather Service Bismarck ND

204 PM CDT Sat Jun 20 2026



.KEY MESSAGES...



- Periodic showers and thunderstorms through Tuesday, with the

  first round starting in the far southwest this evening before

  gradually expanding north and east tonight through Sunday.



- The severe weather threat is low this weekend through at least

  mid next week.



- Near to slightly below average temperatures this afternoon

  with seasonably cool temperatures Sunday. Below average

  temperatures are then favored overall through the middle of 

  next week with a gradual warm-up at the end of the week. 



&&



.DISCUSSION...

Issued at 204 PM CDT Sat Jun 20 2026



Not a whole lot has changed to the ongoing forecast. Upper low 

over eastern BC/Alberta will ever so gradually meander eastward

across southern Canada and eventually down into the Great Lakes

Region through the middle of next week. This will lead to daily

shower and thunderstorm chances through Tuesday. 



Despite daily chances, there are three distinct periods with high 

probabilities of precipitation. The first starts as surface low

pressure develops over central Montana this evening and 

gradually slides eastwards. Initially this produces low chances 

in the far southwest this evening that will become medium to 

high mainly across the western half of the state Sunday. The 

second is Monday afternoon through Monday night as the surface 

low begins to propagate quicker to the east and tightens up, 

which will result in transitory high PoPs from west to east. The

third is Tuesday afternoon, especially in the north and east as

the aforementioned surface low stalls. The current thinking is 

that the severe weather threat on any given day is low. However,

if a few strong to severe storms were to develop, Sunday 

afternoon/evening in the northwest and Monday afternoon/early 

evening in the west and north central would be the most likely 

times and locations. That said, neither SPC nor CSU machine 

learning are highlighting the forecast area at this time, and 

even the most bullish deterministic models generally maintain 

marginal instability and shear.



Beyond Tuesday, mostly dry conditions are favored across the 

forecast area through Thursday night with some minor localized 

exceptions. The NBM then brings the return of additional 

chances initially Friday, but especially this weekend. 

Temperatures are currently forecast to remain below average 

overall through Thursday, before returning to near average 

towards the end of next week.



&&



.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...

Issued at 1238 PM CDT Sat Jun 20 2026



Dry conditions are expected to continue this afternoon before

shower and thunderstorm chances gradually begin to enter the 

southwest this evening. Precipitation chances will then 

continue to increase overnight and through Sunday morning, 

including in the northwest and south central. The terminals most

likely to see precipitation before 18Z Sunday are KDIK and KXWA

with lower chances at KBIS. A few rumbles of thunder are 

possible as well. However, with low confidence, maintained 

PROB30 and prevailing mentions as SHRA for now. Otherwise,

MVFR ceilings associated with this system may encroach into the

far southwest Sunday morning. Diurnal cu over most locations 

north and east of the Missouri River could produce low VFR 

ceilings at times this afternoon, though will gradually rise in

height before dissipating soon after peak heating.



&&



.BIS WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION...Telken

AVIATION...Telken