957
FXUS63 KBIS 081207
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
707 AM CDT Sat Jun 8 2024

.KEY MESSAGES...

- Isolated showers possible today with the highest chances (20
  percent) over the northwest and west-central (Crosby,
  Williston, Watford City, Killdeer, Beach, Medora).

- High temperatures the next few days normal to just below for
  early June (normal is mid 70s). Above normal temperatures are
  expected with increasing confidence for Wedneday (80-85
  degrees).

- Widespread showers and non-severe thunderstorms expected (70
  percent chance) Monday afternoon and Monday night. Then
  stronger thunderstorms possible Wednesday.

&&

.UPDATE...
Issued at 640 AM CDT Sat Jun 8 2024

Current forecast right on target as far as radar and satellite
tools.

&&

.DISCUSSION...
Issued at 430 AM CDT Sat Jun 8 2024

Have gone back and forth on what to do with pops today
(Saturday). NBM yielded no pops for today that would result in a
forecast of a chance for rain while the CAMs indicate an
isolated nature to any showers that do form. As far as
location, depending on which CAM was used, resulted in isolated
shower chances all but the Jamestown area at one or another
point today. Concern for rain today is that the features that
would produce showers are weak, the best of which is slightly
cyclonic flow aloft. To some extent that is countered by the
surface high in Montana ridging into North Dakota and providing
subsidence and relatively dry air from the surface into the mid
levels. We were wondering if it is a virga scenario today where
rain falls from a cloud that can get some vertical growth, but
evaporates before reaching the ground. The highest chance of a
shower, and it is not high, is over the northwest and west-
central, with the strongest, though not very strong, cyclonic
flow / troughing aloft, and at least some instability, on the
order of 200 J`kg. In collaboration with NWS Glasgow, Montana,
we have added a low pop along the MT/ND border and came as far
east as Stanley and Killdeer and as far south as Beach and
Medora. Temperatures today just a few degree lower than what was
seen on Friday.

Guidance has shifted away from brining the H5 low out of Canada
and across North Dakota on Sunday. With that then the pops are
lower and the high temperature forecast is, well, not as low. H5
ridging Sunday and Sunday night should result in dry weather.

For Monday, a long wave H5 trough approaches with southwest
flow aloft and an approaching warm front that will be the focus
for widespread convection, especially Monday afternoon into the
night. Guidance is in agreement and so confidence is high in
that.

There continues to be a wide spread in possible outcomes for
high temperatures in the Tuesday through Thursday time period.
With that said they are higher (warmer) than previously expected
and so confidence remains high that 80s will be common over the
forecast area say on Wednesday (west on Tuesday as well, and
east on Thursday as well).

With that thermal ridge axis over us on Wednesday, and with
instability and wind shear progged to be increasing that day on
southerly flow ahead of a cold front, SPC has highlighted the
eastern Dakotas on the Day 4 Outlook.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 640 AM CDT Sat Jun 8 2024

VFR ceilings and visibility through the TAF valid period.
West wind near 10 knots becoming northwest closer to 20 knots
Saturday afternoon, a bit gustier near showers and virga.
Isolated -SHRA are possible, especially from KXWA to west of
KDIK between 08/16Z and 09/00Z.

&&

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

&&

$$

UPDATE...JPM
DISCUSSION...JPM
AVIATION...JPM