754
FXUS63 KBIS 272344
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
644 PM CDT Mon May 27 2024

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms expected
  through this evening. Severe weather is not anticipated,
  although a few storms may produce small hail and gusty winds.

- Patchy fog is possible tonight, with overnight lows in the
  upper 30s to mid 40s.

- Mainly dry conditions with near to slightly below average
  temperatures expected for Tuesday.

- Windy and warmer conditions on Wednesday. Isolated strong to
  severe storms are possible across the west later in the day
  Wednesday through Wednesday night.

- Through the end of the workweek, chances for showers and
  thunderstorms return with temperatures remaining near to
  slightly above average.

&&

.UPDATE...
Issued at 644 PM CDT Mon May 27 2024

Widely scattered showers and thunderstorms continue across
southern and western portions of the forecast area, in an
environment with 15 to 20 knots of bulk shear and less than 1000
J/kg of bouyancy, per RAP-based mesoanalysis. Additional showers
are moving into northern North Dakota from across the
International Border, but no lightning is expected with this
activity. Freshened up POPs and used coverage wording through
the evening, but otherwise going forecast looks good.

&&

.DISCUSSION...
Issued at 345 PM CDT Mon May 27 2024

A weak boundary followed by a mid level shortwave will continue
to bring isolated showers and thunderstorms through this
evening. MUCAPE of near 1000 J/KG and effective shear of
around 30 knots could bring some small hail. CAPE profiles
overall look skinny, thus hail is expected to be generally less
than an inch in diameter, although cannot rule out an isolated
stronger pulse like storm producing hail to around an inch in
diameter. DCAPE today is fairly low, although some inverted V
soundings are present. An isolated gusty wind 50 to 60 MPH could
be possible with the stronger storms today, although small hail
will likely be the main threat with any thunderstorms. Behind
this wave tonight will be a surface high moving in. This will
lessen the winds and bring clearing skies. Overnight low
temperatures are expected to be in the upper 30s to mid 40s.
Some areas across the north central could get close to patchy
frost, although the temperatures are overall expected to remain
above frost criteria tonight. These light winds and cooling
temps could bring about patchy to areas of fog. For now patchy
fog has been placed in the forecast for much of the area and
will have to be monitored for tonight into Tuesday morning.
Surface high moves eastward Tuesday while an upper level ridge
buildings overhead. The result will be mainly clear skies and
light winds. Areas in the west closer to the building ridge
will be warmer and in the 70s, while eastern areas look to
remain below normal and in the 60s. An increasing pressure
gradient could then bring some breezy winds to the west Tuesday
night. Dry conditions look to remain, while overnight lows
remain in the 40s.

Developing low on Wednesday will bring a breezy to windy
southerly flow. This will also help warm temperatures back into
the 70s for most areas. SPC continues a marginal risk for severe
weather Wednesday through Wednesday night. This still all
depends on timing of the surface low development and then
passage of a cold front. It is interesting to note that high
amounts of instability are starting to be forecast. The ECMWF
EFI even bringing elevated numbers for areas in this marginal
risk. There does still appear to be a lack of shear with most
models putting 0 to 6 km in the 30 to 40 knot range. EFI
CAPE/Shear values are also quite low. Given the modest cape and
shear, a wind and hail threat will be the biggest concerns. Some
convective parameters hint that a nonzero tornado threat is
possible in the southwest. Hodographs do show some turn in the
atmosphere present, although the best veering is more in the 0
to 3 KM layer. 0 to 1 km shear is also elevated. STP values may
peak around 1, yet are mostly below 1. So overall Confidence in
an isolated tornado threat is still low, especially given the
overall lack of shear. The associated cold front then moves
through Wednesday night into Thursday. Perhaps along this front
a line of strong to severe storms could be found with a wind and
hail threat also possible. Wind especially may be of concern
with increasing 0 to 3 KM shear and elevated amounts of DCAPE.
Depending on timing of this front the stronger storm threat
could push eastward quickly through the day Thursday. Behind
this front looks to be slightly cooler temperatures and some
breezy westerly winds.

Friday through the weekend a broad trough to almost zonal flow
pattern could then setup. This may help keep temperatures near
to slightly above average. The unsettled nature of this pattern
has also allowed for at least slight PoPs each day from the NBM.
Those could increase if more well defined waves move through
this pattern. Something to monitor going
forward. CSU-MLP currently not showing much for chances of
severe weather with this feature.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 644 PM CDT Mon May 27 2024

VFR conditions overall expected through the TAF period.
Widely scattered showers and thunderstorms continue across
western and southern North Dakota this evening, as well as some
showers across the north. This activity is expected to diminish
through the night tonight. Although predictability in impacting
any one terminal is low, any heavier showers or thunderstorms
could produce MVFR conditions. Patchy fog is possible tonight
but confidence was too low to include at any terminal with this
update. Tuesday will feature mostly clear skies and light
north to northeast winds, becoming southeasterly towards the end
of the TAF period.

&&

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

&&

$$

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