NZUS93 KBIS 301829
LLLBIS
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051-010629-

Public Information Statement
National Weather Service Bismarck ND
129 PM CDT Wed Apr 30 2025

.Key Messages…

- A band of light rain will continue to slowly move across the 
state through this evening. Amounts should generally be light.
 
- On Thursday, there is a 40 to 80 percent chance of showers 
across the state with the best chances over the central. A few 
thunderstorms are also possible. 

- Above-normal temperatures and dry conditions are forecast to 
return this weekend. Widespread highs in the 80s are possible 
on Sunday.

-Low to medium precipitation chances return late Sunday night 
through Tuesday. A few thunderstorms are possible on Monday. 

&&

.Discussion…

Western and central North Dakota is currently under the 
influence of low amplitude southwest flow aloft as a shortwave 
trough continues to propagate through the region. Plenty of 
cloud cover continues to stream across western and central 
North Dakota as the wave moves through and a band of light rain 
also continues to slowly move across the state from west to 
east behind a cold front.  We should start to see a little bit 
of clearing from west to east later this afternoon and into the 
evening, but the main core of the trough will approach 
overnight, increasing cloud cover once again. Overnight lows 
will range from the upper 30s to the mid 40s. 

The trough axis moves through Thursday morning, leaving western 
and central North Dakota under cyclonic flow aloft through the 
rest of the day. This pattern will lead to widely scattered/numerous 
showers (40 to 80 percent chance) and a few hit or miss 
thunderstorms with the best chances over the central. 
Instability and shear should be fairly weak with RAP soundings 
suggesting up to around 500 j/kg of MUCAPE and deep layer shear 
only maxing out in the 20 to 30 knot range. Thus, a report or 
two of small hail is not out of the question, but the strong to 
severe threat appears low. Precipitation amounts this afternoon 
through Thursday should generally be light. NBM probabilities 
for amounts greater than or equal to a tenth of an inch range 
from around 40 to 80 percent across the southern half of the 
state (and up into portions of the Devils Lake Basin). But 
increasing that threshold to a quarter inch or greater and the 
probabilities only max out around 20 percent. The one exception 
could be the far southern James River Valley where some 
modestly higher totals are possible, or under any heavier 
showers/storms that develop on Thursday.  Highs may be just a bit 
cooler than today on Thursday, ranging from the mid 50s to the 
mid 60s.  

An expansive west coast ridge will start to nudge closer on 
Friday as we transition back into highly amplified northwest 
flow aloft. This ridge will slowly move across the northern 
Plains through the weekend, promoting dry conditions and 
warming temperatures. Highs on Friday will range from the lower 
60s (maybe some upper 50s) southeast, to the upper 60s 
northwest. Highs will mainly be in the 70s on Saturday with an 
outside shot at a few lower 80s across the far west and then 
Sunday should see widespread highs in the upper 70s to the mid 
80s as the ridge axis moves across the region. 

After the ridge axis passes through, we transition back into 
southwest flow aloft later in the day on Sunday and into the 
nighttime hours as a split flow regime develops. While most of 
the forcing will either stay north of the International border 
or south of the South Dakota border, we should still see low to 
medium precipitation chances return late Sunday night through 
Tuesday with the best chances along and behind a cold front 
that will move through on Monday. Monday will also see the 
return of thunderstorm chances as GFS soundings suggest MUCAPE 
up to around 500 J/kg and deep layer shear up to around 40 
knots. Thus, a stronger storm or two may not be out of the 
question depending on how the forecast evolves. CSU Machine 
Learning guidance is also suggesting a low chance for severe 
thunderstorms on Monday so it will be a period to monitor 
closely. As of now, precipitation amounts appear to be on the 
lighter side next week with NBM probabilities of a tenth of an 
inch or more maxing out in the 30 to 50 percent range. 
Increasing the threshold to a half inch and the probabilities 
only max out at 20 percent. Highs will be cooler west on Monday 
behind the cold front, ranging from the mid to upper 60s 
northwest, to the upper 70s southeast. Highs on Tuesday will 
then range from the mid 60s to lower 70s.

$$

ZH