080
FXUS63 KBIS 071955
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
255 PM CDT Fri Jun 7 2024

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms will remain
  possible through this evening. Thunderstorms are generally
  expected to be below severe limits, however, an isolated
  stronger storm is possible in southcentral and portions of
  southwestern North Dakota with nickel sized hail and winds up
  to 50 mph being the main threats.

- Isolated showers (20 percent chance for rain) are forecast for
  Saturday. High temperatures to remain near to slightly below
  seasonable normals. There is a 10 percent chance of showers
  during the day Sunday, increasing to 30 percent at night.

- Widespread chances (20 to 50 percent) for showers and
  thunderstorms to be found Monday.

- Cooler temperatures expected Sunday and Monday. How much
  cooler still remains uncertain. Moderate to high confidence
  remains for warmer temperatures during the middle of next
  week with high temperatures into the 80s.

&&

.DISCUSSION...
Issued at 255 PM CDT Fri Jun 7 2024

A weak disturbance in northwest flow could still bring showers
and thunderstorms through this evening. SPC maintains a
Marginal Risk of severe weather in southcentral and portions of
southwestern North Dakota through this evening. The threat for
severe weather overall looks very isolated today. Some HRRR
CAMS are showing an isolated stronger storm later this afternoon
into this evening across these marginal risk areas. There is
abundant shear in this area during this time period. The bigger
concern though is the lack of instability. HREF ensemble data
showing MUCAPE up to 500 J/KG. While surface based CAPE is
higher in some instances, the elevated nature of today`s
convection would be tough to tap into this. A quick change from
easterly flow at the surface to westerly flow aloft could be
adding some SRH and perhaps promote weak rotation in isolated
storms, yet again this would require surface based storms. More
looking into the elevated storm environment the hodographs
become more straight. This could still help with hail
production, especially given the high amounts of shear. The
concern still remains the lack of instability. There is a weak
warm front boundary setting up as well in these Marginal Risk
areas. If a stronger storm can get going along this boundary and
pulse up, then perhaps hail up to an inch in diameter and wind
gusts up to 60 mph are possible. For now kept messaging sub
severe as this is where our highest confidence currently
resides given the lack of instability. Precipitation activity
should diminish shortly after midnight tonight. Look for
overnight lows to be in the 40s, and light winds tonight as they
switch back to a westerly direction. A broad upper low then
looks to linger in southern Canada for Saturday maintaining the
near to slightly below normal temperatures across the CWA. The
unsettled northwest flow could result in a few isolated showers
Saturday, with the higher confidence areas coming in the north
where a weak frontal boundary may help with lift. Instability
lacks even more than today, thus left our mention of
thunderstorms for Saturday. Northwest winds may increase
slightly for Saturday, yet be below advisory criteria. Sunday
still remains a day of uncertainty as temperature and
precipitation chances will highly depend on how far south this
cut off low can progress. Clusters are about 50/50 on the low`s
location which brings quite the spread in temperatures. There is
somewhat of consensus that below normal temperatures will be
found. How cold will depend on this location. NBM may have
raised slightly today compared to last night, although this may
be the trend until more model consensus can be found. NBM also
keeps Sunday mainly dry for the time being, again dependent on
the lows placement. A wave moving across the Pacific North West
could then lift across the area Sunday night through Monday.
This will linger cooler temperatures, yet make the next chance
for widespread showers and thunderstorms. There is a high amount
of shear during this time period, although instability looks
limited. The chance for severe weather perhaps will need to be
monitored going forward given the amount of shear available. One
last note for the weekend, cooler temperatures could also be
found in the morning with perhaps some upper 30s possible Sunday
morning.

Ridging to flat ridging could then be found through mid next
week. This westerly flow could bring some warming temperatures,
with NBM placing highs in the mid 70s to mid 80s for much of the
CWA. Flat ridging could promote a few weak waves in the flow and
possibly bring a shower or thunderstorm at times. Predictability
is low for this pattern at this time and left in NBM PoPs for
now. Clusters then indicate perhaps a return to a broad trough
or at least northwest flow pattern. This may slightly cool the
temperatures and bring more chances for showers and
thunderstorms. CSU-MLP putting in some slight chances for severe
weather mid to late next week. These chances are isolated to scattered
and will have to be monitored going forward.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1245 PM CDT Fri Jun 7 2024

VFR conditions generally expected through the forecast period.
Isolated to scattered showers and thunderstorms could be found
through this evening. Confidence was high enough to include
shower mention to most sites. It was only high enough to include
TS mention to the KBIS and KJMS TAF site. Precipitation looks to
diminish later this evening bringing clearing skies and
continued VFR conditions. VFR conditions are then expected for
much of Saturday. Light winds will become easterly today. These
easterly winds will then become westerly tonight into Saturday.

&&

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

&&

$$

DISCUSSION...Anglin
AVIATION...Anglin