975
FXUS63 KBIS 270229
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
929 PM CDT Sun May 26 2024

.KEY MESSAGES...

- Scattered showers and isolated thunderstorms through this
  evening. Isolated showers with a possible thunderstorm
  overnight.

- Isolated to scattered showers and thunderstorms Memorial Day.
  High temperatures will generally be in the 60s. Breezy south.

- Generally dry conditions and warming temperatures Tuesday
  into Wednesday.

- Later Wednesday through the end of the work week, chances for
  showers and thunderstorms return with temperatures remaining
  near to slightly above normal.

&&

.UPDATE...
Issued at 907 PM CDT Sun May 26 2024

Scattered showers and a few thunderstorms remain mainly over
northern and eastern portions of the forecast area and will
continue to track east this evening and into the early
overnight hours. We have adjusted pops and sky cover again based
on latest radar and satellite imagery. We also added some
slight chance pops southwest, ahead of a shortwave currently
moving into west central ND. Current radar shows some radar
returns over east central MT moving into west central/southwest
ND. We also made some small adjustments to pops late tonight
through Monday morning based on a blend of short term guidance.
This results in mostly minimal (20-30%) pops over central ND
through the morning and mostly dry over western ND.

UPDATE
Issued at 548 PM CDT Sun May 26 2024

Scattered to numerous showers and isolated thunderstorms
continue to track eastward across western and central North
Dakota early this evening. We`ve had a report or two of some pea
sized hail and have seen gusts to around 35 mph with a few of
the stronger thunderstorms. Most of the activity has produced
brief heavy rainfall. If you do have outdoor plans this
evening, remain alert to the potential for thunderstorms amongst
the general shower activity and move indoors if you hear
thunder.

We made some small adjustments to pops and sky cover based on
the latest radar and satellite imagery. Otherwise no changes to
the going forecast.

&&

.DISCUSSION...
Issued at 340 PM CDT Sun May 26 2024

Shortwave trough wrapping around a stalled upper low in Canada
will bring widespread showers and thunderstorms through this
evening. A few of these storms could be strong as MUCAPE of near
1000 J/KG will be found. The skinny cape profile though should
make large hail tough, as well as the overall lack of shear.
Expect more pulse like thunderstorms that may be strong briefly
then diminish, and could produce hail of a half inch to an inch.
Inverted V soundings and small amounts of DCAPE could also
promote some gusty winds of 50 to perhaps 60 MPH in the
strongest storms. Once the wave moves more eastward later this
evening through tonight showers and thunderstorms should become
more isolated tonight. Lingering cloud cover should keep
overnight lows in the 40s, limiting the frost potential. There
could be some lower clouds or perhaps patchy fog tonight. Fog is
not in the forecast at this time, although northern and eastern
areas do have some potential for this to occur. The main upper
low in Canada looks to move southward on Memorial Day extending
a trough into North Dakota. This could bring some isolated to
scattered showers and thunderstorms. Instability looks even less
for Monday, with shear also remaining low. Thus severe
thunderstorms are not expected at this time. THe increased
gradient could bring some breezy northwest winds on Memorial
Day, mainly south and east. Look for temperatures to be slightly
below normal and in the 60s. Skies go on a clearing trend Monday
night, with wind also going light. This could bring some cool
temperatures and perhaps some patchy fog. Lows in the upper 30s
to upper 40s are forecast. Perhaps some patchy frost could
return to the north central if overnight lows dip further, which
will have to monitored.

Tuesday, a building ridge will bring mainly clear skies and dry
conditions. Areas closer to the ridge in the west will see
warming temperatures, while eastern areas remain in the
northwest flow pattern and see cooler temperatures in the 60s.
Ridge starts out overhead on Wednesday, with a transition to
southwest flow aloft throughout the day. A developing low lee of
the northern Rockies could bring tight pressure gradient. This
could bring a warm yet breezy to windy southerly flow. This
unsettled setup could also return showers and thunderstorms to
the west Wednesday afternoon and evening. Instability and shear
go on the increase during this time period, perhaps bringing
some strong to severe thunderstorms as also indicated by the
CSU-MLP. A front and the upper wave then looks to move through
on Thursday. CSU-MLP also showing the possibility of severe
weather when this does so, which will also have to be monitored.
A breezy southerly wind could become a breezy westerly wind
depending on the timing of this wave. Warm temperatures on
Wednesday may also linger into Thursday, also depending on
timing.

An upper low may then linger across southern Canada through much
of the upcoming weekend. The resultant westerly flow could
continue to bring near to slightly above normal temperatures.
This unsettled pattern could also bring some showers and
thunderstorms, although predictability at this point is low and
the NBM generally maintains slight pops at times through this
time period.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 548 PM CDT Sun May 26 2024

Scattered to numerous showers and isolated thunderstorms
continue to move east across central and western ND.
Thunderstorms activity around KMOT and KBIS at this time and
may need to include Thunder to begin the TAF. Will include VCTS
elsewhere to begin the TAF period, except KDIK which activity
has moved out of the southwest. Shower activity will diminish
later this evening. Late tonight into Monday morning a band of
MVFR clouds is expected to drop south from Canada and clip KMOT,
KBIS and KJMS with a period of MVFR cigs mid morning to early
afternoon. KDIK and KXWA currently expected to remain VFR.
Isolated to scattered shower activity is expected again Monday
afternoon with best chances north and east. Too far out at this
time to include in any TAF. Light surface flow central ND and
westerly flow in the west becomes west to northwest this evening
then northwest to north Monday generally 10 to 20 knots.

&&

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

&&

$$

UPDATE...TWH
DISCUSSION...TWH
AVIATION...TWH