336
FXUS63 KBIS 060230
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
930 PM CDT Fri Jul 5 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms (30 to 60 percent) will
  continue late this evening into the overnight hours across
  western and central North Dakota.

- Daily chances (30 to 60 percent) for showers and
  thunderstorms continue through the weekend.

- A gradual warming and drying trend is expected for next week.

&&

.UPDATE...
Issued at 928 PM CDT Fri Jul 5 2024

A broken line of thunderstorms from Williams to Bowman Counties is
slowly moving east late this evening. These storms have been strong
at times, with a peak wind gust of 51 mph in Golden Valley County
and dime size hail recently reported in Bowman County. Since 9 PM
CDT, these storms have shown a weakening trend. While we expect this
trend to continue given the impending decrease in diurnally-driven
instability, there is now a smaller area of 0-3 km bulk shear as
high as 35 kts centered over Hettinger and Adams Counties per SPC
mesoanalysis.

Farther to the east, storms have been more isolated and are also
beginning to weaken. Storms from western McLean to southern Ward
Counties this evening have had a history of producing funnel clouds.
The most recent report of a funnel cloud was near Rice Lake around
830 to 845 PM CDT, which is unusually late in the day for this
phenomenon. The risk for cold air funnels should greatly diminish
after sunset.

UPDATE
Issued at 714 PM CDT Fri Jul 5 2024

Showers and thunderstorms have become more widespread across the
western half of the state since late afternoon, while remaining more
isolated along and east of Highway 83. The strongest storms in North
Dakota, which since 6 PM CDT have been widely scattered along a
meridional corridor from Burke to Hettinger Counties, have shown
signs of producing hail around half an inch in diameter or smaller.
These storms have been very pulse in nature given the moderate
CAPE/no shear environment. Another broken line of storms moving
across eastern Montana has a history of producing gusts to
around 60 mph from around Glasgow to Poplar, and now more
recently at Glendive. The environment there is similar to
western North Dakota, with perhaps just slightly stronger 0-3 km
bulk shear (still less than 30 kts) but negligible effective
bulk shear. With the slight enhancement in 0-3 km shear expected
to translate eastward with the line of storms, a few gusts in
the 50 to 60 mph range cannot be ruled out across far western
North Dakota through 9 PM CDT.

At around 4 PM MDT, at least one cold air funnel was spotted near
Dickinson. No other reports have been received anywhere else since,
and the low level buoyancy needed to produce these funnel clouds is
now waning. Until we see a more distinct pattern shift, which as
noted below is forecast to commence on Monday, conditions could
materialize to support afternoon cold air funnels with showers and
storms through the weekend.

&&

.DISCUSSION...
Issued at 223 PM CDT Fri Jul 5 2024

The weather pattern today looks quite similar to yesterday. Weak
progressive ridging is currently located over western and
central North Dakota and this feature has been the main reason
showers and storms have been a little slower to get going than
yesterday. That being said, another fast moving upper low will
track into the area later today and tonight, bringing more
scattered showers and isolated to scattered thunderstorms (30 to
60 percent chance). The severe weather potential remains low.
While MLCAPE will max out around 1000 to 1500 J/kg, shear will
be very low. Still, given slow storm motions, locally heavy
rainfall will be possible along with some small hail and
frequent lightning. Given the lack of shear, weak
funnels/landspouts could be a concern similar to yesterday, but
the upper low has moved well east so background vorticity is
not as elevated. Thus, we do not think the threat is as high
but SPC mesoanalysis does suggest some pockets of the non-
supercell tornado parameter up to one, likely driven by the weak
shear and strong low level CAPE. Highs this afternoon will be
in the 70s.

The story remains pretty much the same for Saturday and Sunday
with more chances of showers and thunderstorms (30 to 70
percent) with the best chances currently looking like Saturday
afternoon. Severe weather chances remain low given a similar
environment as today. Highs will mainly be in the 70s again on
Saturday and Sunday but we may start to see some lower 80s by
Sunday.

We dry out on Monday as an expansive western ridge finally
starts to nudge into the region. There could be a window for a
few showers or storms across the north central and northeast on
Tuesday as a weak wave rides down the ridge but we are talking
maybe a couple hundredths of liquid at the most. Expect a
gradual warming trend through the week with some upper 80s back
in the forecast by Wednesday and some lower 90s by the end of
the week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 928 PM CDT Fri Jul 5 2024

Scattered showers and thunderstorms remain possible across western
and central North Dakota this evening through tonight. KJMS has the
lowest probability of showers and storms this evening. Meanwhile,
storms moving across western North Dakota late this evening
could produce gusty northwest winds as high as 35 kts. Other
showers and storms are far less likely to produce gusty winds,
but a brief period of IFR visibility can be expected with any
heavier shower or storm. Later tonight through Saturday morning,
the highest chances for showers and perhaps a few thunderstorms
will focus more over south central and into southeast North
Dakota, with coverage of showers and storms once again expected
to become more widespread across the state Saturday afternoon.
Outside of showers and storms, VFR conditions and light winds
are expected through the forecast period. Some smoke from
Canadian wildfires has been noted aloft, but it is unlikely to
significantly impact aviation.

&&

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

&&

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

&&

$$

UPDATE...Hollan
DISCUSSION...ZH
AVIATION...Hollan