628
FXUS63 KBIS 041900
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
200 PM CDT Thu Jul 4 2024

.KEY MESSAGES...

- Numerous showers and scattered thunderstorms will continue
  through the afternoon, diminishing this evening.

- However, the entire day will not be a washout for most, as
  much of the activity will be of the "hit or miss" variety.

- The story will be much of the same Friday through Sunday with
  daily chances (30 to 60 percent) of showers and scattered
  thunderstorms.

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

&&

.DISCUSSION...
Issued at 200 PM CDT Thu Jul 4 2024

Western and central North Dakota currently sits under the
influence of a broad upper low overhead and an expansive
amplified ridge to our west. Cyclonic flow will maintain
numerous showers and scattered thunderstorms through the
afternoon and into the evening across most of western and
central North Dakota. These storms will be your typical
popcorn/hit or miss summertime thunderstorms with a skinny CAPE
profile and very low shear. However, we have started to notice
a bit of a training trend, especially along the line from just
southeast of Harvey, down to near Moffit. MRMS estimates we`ve
seen anywhere from an inch to 2.5 inches of rain along this line
of storms in the past couple of hours. There may be some small
hail contamination with a few storms but reports suggest these
are efficient rain producers with some rainfall rates of 1 to 3
inches or greater an hour. If sufficient training can maintain
itself, a localized flooding environment here could end up
materializing through the afternoon. Thus far, MRMS Crest Unit
Streamflow has only shown minimal response.

Showers and storms will last into the early evening but should
start to diminish with the loss of diurnal heating. Lows tonight
will be in the 50s under a partly to mostly cloudy sky.

The upper low kicks out to the east by Friday morning and low
amplitude ridging moves quickly across the state through the
first part of the day. A subtle shortwave embedded within the
larger western US ridge will approach in the afternoon hours,
leading to another thunderstorm environment similar to today
with some decent instability but little to no shear. Coverage
will be similar, very hit or miss with popcorn convection. Rinse
and repeat on Saturday as another compact upper low rides down
the western ridge and brings us yet another round of popcorn
convection.

The western ridge then finally starts to nudge closer to us on
Sunday, shifting the best chances of scattered showers and
storms to the eastern half of the forecast area. Highs will be
in the 70s through Sunday.

By Monday, we start to dry out as the ridge continues to
approach. This will also help warm temperatures through the
week. We start off with highs in the mid 70s to lower 80s on
Monday, warming into the 80s and possibly even some lower 90s by
mid to late week. NBM temperature spread is very low
considering the time frame so it seems like ensembles are in
fairly good agreement that this western ridge will be a main
driver for our weather pattern next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1235 PM CDT Thu Jul 4 2024

Hit or miss thunderstorms continue to increase in coverage and
intensity as expected early this afternoon. The isolated to
scattered nature of the convection makes the precipitation
forecast complicated for any individual point. Thus, we are
relying heavily on vicinity wording and tempo groups for the
18z TAF period. Severe storms are not expected but the strongest
storms may produce locally heavy rainfall and small hail. If a
heavier storm moves overhead, brief MVFR to IFR visibilities
will be possible. Some embedded MVFR ceilings are not out of the
question either but it seems that most will see VFR ceilings
through the period. Showers and storms will start to diminish in
the evening. Winds may become gusty and erratic in and around
any thunderstorms.

&&

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

&&

$$

DISCUSSION...ZH
AVIATION...ZH