143
FXUS63 KBIS 281727
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1227 PM CDT Thu Aug 28 2025

.KEY MESSAGES...

- Near seasonable high temperatures in the mid 70s to mid 80s
  today through Labor Day, with lows generally in the 50s.

- Low chances for showers and thunderstorms, mainly south,
  Friday through Labor Day. The probability for severe weather
  is very low.

&&

.UPDATE...
Issued at 1227 PM CDT Thu Aug 28 2025

Quiet with increasing cirrus to start the afternoon. Some of
the recent CAMs runs produce isolated showers and thunderstorms
across parts of mainly north central North Dakota this evening,
while others speed up the timing of precipitation chances in
southwest North Dakota late this evening. Deterministic
guidance still pretty confident on very limited instability and
bulk shear, so the potential for any stronger storms, if we do
get any thunderstorms at all, is quite low. Going forecast looks
good for now.

UPDATE
Issued at 953 AM CDT Thu Aug 28 2025

What little remains of patchy fog across the area will be
diminishing within the next hour as temperatures continue to
warm. Generally quiet day expected, with visible satellite
imagery showing much more expansive cloud cover across central
Montana that will be shifting east through the day. No changes
needed with this update.

UPDATE
Issued at 645 AM CDT Thu Aug 28 2025

A few patchy fog reports are starting to come in across central
and eastern North Dakota. Some fog is also starting to show up
on the Nighttime RGB Satellite products. Observations still
appear to be patchy, yet fog may remain into the mid morning
hours. Have expanded patchy fog mention to include much of
central and eastern ND. Otherwise the forecast remains on track.

&&

.DISCUSSION...
Issued at 338 AM CDT Thu Aug 28 2025

Temperatures near saturation combined with light winds could
bring some patchy fog this morning across some central and
eastern portions. Otherwise look for another warm day with highs
in the 80s, along with light winds, mainly dry conditions, and
some increasing clouds. Some CAMs do have some isolated shower
or perhaps even thunderstorm activity along a weak boundary of
instability this afternoon into the early evening across the
north central to some eastern portions. There is 500 to 1000
J/KG surface cape in these areas, although shear is low. If
these low topped thunderstorms can form they would be mainly
diurnal and short lived. Placed 10 percent chance for these
areas, yet did not have high enough confidence to include
thunderstorm mention in the forecast at this time. Afternoon
humidity values may lower into the 20s across the west, although
the lack of winds will limit any fire weather concerns today.
Tonight will see increasing clouds and perhaps an isolated
shower in the far southwest. Lows will mainly be in the 50s.
Some patchy fog may return in the east, although confidence was
not high enough to include in the forecast at this time.

Broad upper low then looks to move into the region tonight and
settle in for Friday and Saturday. This will return chances for
showers and perhaps a few thunderstorms to mainly southern
portions of the state. High pressure in the lower levels across
Canada could control how far south this low moves and currently
looks to limit precipitation chances in the north, and perhaps
even further south depending how far south this high can push.
For now NBM continues precipitation chances for the southern
half of the state. There looks to be enough instability for
thunderstorms, although the lack of shear and lift will make
the threat for severe weather very low. High temperatures to
start the holiday weekend will mainly be in the mid 70s to mid
80s, although may slightly cool Saturday. Sunday and Labor Day
could see less of a chance of showers and thunderstorms as this
weak cutoff low slowly moves eastward. Temperatures will remain
in the mid 70s to mid 80s, while lows remain in the 50s.

Models continue to show a more defined shortwave trough will
pass through the region sometime Tuesday or Wednesday of next
week, along with an associated cold surface frontal boundary. As
a result, the NBM has produced shower and thunderstorm chances
during this time period, while favoring another cooling trend.
That said, the NBM ensemble temperature spread remains quite
high, especially on Wednesday and even show a warming trend
after Wednesday. This suggests a lack of agreement as to the
timing of the aforementioned cold frontal boundary and the upper
level pattern afterwards. Some breezy winds may also accompany
this front passage, although a strong wind signal is not
currently showing up in the ECMWF EFI values.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1227 PM CDT Thu Aug 28 2025

VFR conditions at all terminals expected through the TAF period.
Mid to high clouds will continue expanding across the forecast
area through the TAF period. There are very low chances for
isolated showers and thunderstorms late this afternoon and
evening across northern North Dakota, and additional chances
overnight and into Friday morning across the southwest.
Confidence in these impacting any terminals was too low to
include with this update.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Jones
DISCUSSION...Anglin
AVIATION...Jones