298
FXUS63 KBIS 262349
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
649 PM CDT Fri Apr 26 2024

.KEY MESSAGES...

- Periods of showers (70 to 100 percent) will continue this
  evening over most of western and central North Dakota before
  showers gradually diminishing west to east. Isolated
  thunderstorms are possible through early this evening, mainly
  south. Severe weather is not expected.

- Expect low to medium chances (20 to 40 percent) for showers
  across southern North Dakota Saturday and Saturday night. A stronger
  storm system will then bring higher chances for showers (90
  percent southeast to 10 percent northwest) on Sunday and
  Sunday night.

- We will see cooler temperatures today through Sunday and then
  a warming trend is on tap for the next work week when return
  to near/above normal values.

&&

.UPDATE...
Issued at 636 PM CDT Fri Apr 26 2024

Rain showers continue, primarily over central North Dakota.
Latest guidance continues to show the trend of precipitation
diminishing over the west this evening, but probably lingering
later into the night over central parts of the state before
diminishing, possibly hanging on until early Saturday morning.


&&

.DISCUSSION...
Issued at 131 PM CDT Fri Apr 26 2024

A stacked low continues to spin in the vicinity of Nebraska to
our south. For the rest of today and into tonight, we will see
bands of light to moderate rain showers spiraling around this
low. This will mean more widespread showers today and tonight
for most of western and central North Dakota. The one major
exception will be across the far west as we have seen some
clearing here. Some observed dry slotting in the James River
Valley could also lead to some more hit and miss activity.

Currently, SPC mesoanalysis shows about 500 J/kg of surface
based CAPE across the southwest, mainly where we have some
clearing. Given a fairly stable atmosphere where current
precipitation is located, any thunder later his afternoon would
likely be isolated and confined mainly to the south.

Regarding precipitation totals for this first wave through
Saturday morning, the NBM still suggests medium to high chances
(40 to 80 percent) for a half inch of additional rain or more
across much of the central and east. Increasing that threshold
to an inch and the probabilities dip more into the 10 to 20
percent range.

The other story for today will be ongoing near critical fire
weather conditions across the far northwest. We have seen some
clearing across the west with increasing winds out of the north
behind a slow moving cold front. A dry lower atmosphere here
along with temperatures that have risen into the upper 60s and
lower 70s, has led to humidity values dropping into the upper
teens and lower 20s (percent). Sustained winds thus far have
risen to as high as 25 mph over portions of Divide and Williams
counties to go with lower humidity but the spotty nature of
stronger winds should keep critical fire weather conditions
from developing uninterrupted for 3 hours or more.

Most of the precipitation should move out overnight tonight or
Saturday morning. Most will likely then see a break in rain
chances through the day on Saturday before another low ejects
out of the central Plains and into the northern Plains Saturday
night into Sunday. There are still a couple of scenarios for the
eventual track of this low, and much will depend on how strong
a ridge axis becomes to our east. If we see a stronger ridge
axis, the track of the low may end up further west, bringing
widespread rain to much of the area. A weaker ridge axis to our
east would allow for the low to track further east, leaving the
heaviest precipitation to our south central and eastern areas.
For now, both scenarios appear to have about equal chances.
According to the latest NBM run, the best chance for another
quarter inch or more of rain will be across portions of the
south central and James River Valley (40 to 70 percent).

After precipitation moves out Monday morning, we should see a
progressive upper level ridge axis moving in, leading to some
clearing from west to east through the day. We should also see
some warmer temperatures with highs ranging from the low to mid
50s east (under lingering cloud cover), to the mid to upper 60s
west (under a mostly sunny to partly cloudy sky). Highs will be
fairly similar through the rest of the work week, mainly in the
50s and 60s. A couple of quick moving waves will then propagate
across the region through the week with the strongest wave
likely to move through Monday night and Tuesday (low to medium
chances for showers across most of the forecast area). Low
chances for showers should continue then until at least
Thursday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 636 PM CDT Fri Apr 26 2024

Widespread IFR conditions will continue over southwest and central
North Dakota into the James River Valley including the KDIK,
KMOT, KBIS, and KJMS through tonight, with very gradual
improvement from west to east overnight into Saturday. VFR
conditions will continue to prevail over northwest North Dakota.

&&

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

&&

$$

UPDATE...JJS
DISCUSSION...ZH
AVIATION...JJS