299
FXUS63 KBIS 010751
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
251 AM CDT Tue Jul 1 2025

.KEY MESSAGES...

- Low chances for occasional showers and thunderstorms through
  Thursday afternoon.

- Gradual warming trend through Thursday, with increasing
  humidity and temperatures in the 90s.

- Medium to high chances for showers and thunderstorms Thursday
  evening through the holiday weekend. A few storms could be
  strong to severe Thursday evening and Friday, and produce
  locally heavy rainfall.

&&

.DISCUSSION...
Issued at 250 AM CDT Tue Jul 1 2025

Currently surface high pressure dominates the Northern Great
Plains. Aloft a ridge is moving in, with a strong thermal ridge
at 850mb. Surface winds across the state today will be variable
in direction due to the high pressure moving across. Wind speeds
however will be around 10 mph, expect for the far southwest,
where winds could be closer to 20 mph from the south. With this
ridge moving in, today will start the warming trend up to the
mid 90s by Thursday. Today`s highs will be in the mid to upper
80s. None of these day will feature the warming west or
southwest wind however, so wouldn`t expect these temperatures to
overperform. Thursday and Friday will be breezy. Thursday the
eastern half will gust to around 30 mph from the south off the
pressure gradient from a surface low and warm front (more on
this later). Friday is the exact same thing but from a different
low pressure.

Wednesday a few little disturbances off the mountains in
Montana move through, bringing a low chance of showers and
thunderstorms late Wednesday night through Thursday. Then,
Thursday morning southwest flow aloft becomes the pattern, which
means more thunderstorms. A Colorado Low develops, which will
swing a warm front through the state Thursday evening. Most
models have CAPE around 1500 J/kg or more. However each model
has different timing and strength. For shear we would have
plenty for supercells with most models having 35-40kts. Model
soundings have a lot of low level helicity and very curved
hodographs, indicating a higher tornado threat. All of this is
very conditional as very warm temperatures at 850mb will be
capping the atmosphere. If the cap can break with strong surface
based CAPE from a very hot and humid day, then strong to severe storms
will occur.

Another low pressure will enter Friday, with more medium to high
chances for showers and thunderstorms. This time, precipitable
Water (PWAT) could be very high. Models slightly differ on this
but the signal has been there a few days. This means the
atmosphere could produce a lot of rainfall, leading to flash
flooding concerns. Saturday another low looks to move through
leading to more chances for showers and thunderstorms. Then next
week looks the same with daily chances for rain as a train of
Canadian Pacific lows move through. Highs will remain mostly in
the 80s next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1257 AM CDT Tue Jul 1 2025

VFR CIGs and VIS through the entire period. Light and variable
winds tonight and into Tuesday morning. Wind directions will be
different throughout the state, but should only be around 12kts.

&&

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

&&

$$

DISCUSSION...Smith
AVIATION...Smith