000
FXUS63 KBIS 231808
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
108 PM CDT Tue Apr 23 2024

.KEY MESSAGES...

- Decreasing winds today with clearing skies and highs in the
  lower 50s to lower 60s.

- Temperatures will warm on Wednesday and Thursday, with
  widespread highs in the 70s likely on Thursday.

- A more active pattern begins on Thursday and continues through
  the weekend. Showers and thunderstorms are possible (50-70%)
  Thursday night through Friday, with the highest probabilities
  across southern North Dakota.

&&

.UPDATE...
Issued at 1256 PM CDT Tue Apr 23 2024

Some cumulus clouds are forming across the southern half of the
state. Stronger winds aloft will continue to mix down to the
surface resulting in breezy winds across central and eastern
North Dakota. Winds will continue to decrease as surface high
pressure moves in from the west by this evening. Updated
temperatures and winds to match current trends and conditions.

UPDATE
Issued at 957 AM CDT Tue Apr 23 2024

The surface low continues to push into the Great Lakes region
while surface high pressure builds over eastern Montana. Thus
leading to a tight surface pressure gradient over the eastern
half of the state. Windy conditions will continue to decrease as
the surface high pressure moves in from the west later this
afternoon. Skies have also cleared out as morning showers
diminished and pushed eastward and surface high pressure moves
westward. Therefore, the sky grids were updated to match
current conditions. No other updates are needed at this time as
the forecast remains on track.

UPDATE
Issued at 638 AM CDT Tue Apr 23 2024

Surface low is analyzed in northern Minnesota, with associated
rain showers gone from the forecast area. Nighttime satellite
imagery shows some low clouds still lingering in the James River
Valley, but these will be dissipating over the next couple of
hours. To our west, a broad surface high extends across Montana,
with pressure rises slowly moving into western North Dakota.
Winds have responded accordingly with current winds under 10 mph
in our western tier of counties, while the central and east,
closer to the surface low, are still seeing breezy northwest
winds. Expect the remaining breezy winds to slowly diminish from
west to east through the day, with noticeably lower winds
everywhere by late afternoon. No major changes needed with this
update.

&&

.DISCUSSION...
Issued at 348 AM CDT Tue Apr 23 2024

This morning, our synoptic pattern is dominated by strong
cyclonic flow, with a surface low centered to our northeast in
southwest Ontario. Very isolated rain showers continue across
central North Dakota, but this activity is diminishing as
expected. Scattered low ceilings are accompanying these showers,
and a persistent pressure gradient has kept breezy northwest
winds ongoing through the night, with occasional gusts to 30
mph. As the low continues to track east through the day today,
winds will die off and cloud cover will decrease, leading to a
pleasant April day by this afternoon. Expect mostly sunny skies
and highs in the lower 50s to lower 60s.

Shallow northwest flow aloft and a weak impulse moving through on
Wednesday will lead to increased cloud cover through the day,
but breezy, southerly surface flow will help warm highs into
the mid 60s to lower 70s. Can`t rule out near critical fire
weather conditions across parts of the southwest and south
central on Wednesday, depending on wind speeds, with minimum
relative humidity dropping into the lower to mid 20 percent
range.

Early on Thursday, upper flow is projected to flatten with a
weak low- level thermal ridge building in,  before more
persistent southwest flow aloft sets up late Thursday and
favors an active pattern through the weekend. NBM temperature
percentiles are fairly confident in widespread highs in the 70s.
Southerly flow will again be breezy, especially in the south
central and southeast.

Thursday could potentially be our first shot at more widespread
thunderstorms this season, with seasonably warm surface temps
and a somewhat moist southerly flow underneath a leading
shortwave. Deterministic guidance and forecast soundings are
advertising up to 1000 J/kg of MUCAPE and modest mid-level lapse
rates around 7 C/km. The limiting factor is likely to be shear,
with relatively weak flow aloft and 0-6 km shear around 20-25
knots in the area with strongest instability (southwest ND). CSU
machine learning probabilities do have low but non-zero probs
for severe hail across the southwest.

Guidance is honing in on a warm-season Colorado Low moving
through the region this weekend, with EC and GEFS ensemble
member low locations in relative agreement on the surface low
tracking northeast through South Dakota and Nebraska. The
placement of the low will influence how far northwest the
precipitation shield ends up, with northwest North Dakota
currently seeing very low probabilities of any meaningful rain.
After Thursday`s activity, rain chances increase further on
Friday as the Colorado Low approaches and precipitation wraps
around the stacked low. Latest NBM probabilities are
highlighting south central and southeast North Dakota for a
medium chance (40-60%) of at least 0.50" of rain Friday and
Saturday. It`s worth noting that the placement of higher
probabilities is consistent through the weekend (higher
southeast and lower northwest), so our main focus is not on
specific amounts but on the general pattern, especially as any
thunderstorms could produce locally higher rain amounts.

Temperatures will cool off through the weekend as a cold front
is progged to move through on Friday, dropping highs back into
the 50s for Saturday and Sunday. Cluster analysis shows ensemble
members are relatively consistent on a second trough moving
through mean southwest flow late in the weekend, keeping
widespread precipitation chances (20-40%) across the forecast
area through Sunday. There are some hints of rebounding
temperatures to start next work week, although NBM precipitation
probabilities and CIPs Extended Analogs both advertise the
active pattern persisting into the start of May.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1256 PM CDT Tue Apr 23 2024

VFR conditions will continue through the latest TAF cycle. Winds
will begin to veer from the north this afternoon to the south by
tomorrow morning. Gusty afternoon winds around 20kts are still
possible at KJMS and KBIS, but winds will continue to trend
downward through the evening. Some scattered cumulus is forming
across the south but will remain around 5000 ft and will
diminish around sunset.

&&

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

&&

$$

UPDATE...Johnson
DISCUSSION...Jones
AVIATION...Johnson