433 
FXUS63 KBIS 231748
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1248 PM CDT Fri Apr 23 2021

.UPDATE...
Issued at 1244 PM CDT Fri Apr 23 2021

Little updates needed early this afternoon. Minor adjustments to
clouds and winds based on current trends. 

UPDATE Issued at 952 AM CDT Fri Apr 23 2021

Limited changes needed this morning. Cold front continues to
progress across the state and will bring cooler temperatures and
northerly breezes today. A band of light rain and snow is still
possible from north to south today through this evening. Dry air
at the surface may limit these showers. Trended pops down to
mostly slight chance, with some chance pops in the southwest.
Otherwise expect highs in the upper 30s to low 40s today. The
mentioned dry air may bring very low RH values in the north.
Decreasing winds by this afternoon should limit the fire weather
threat.

UPDATE Issued at 643 AM CDT Fri Apr 23 2021

Cold front is just pushing through the far southeast corner of the
CWA. Widespread MVFR clouds continue to expand across the forecast
behind the cold front. A band of light snow over northwest ND,
will continue to track southeast through the forecast area during
the day. Little if any precip expected. Made some minor
adjustments to sky cover through the day, otherwise no changes
with this morning update. 

&&

.SHORT TERM...(Today and tonight)
Issued at 230 AM CDT Fri Apr 23 2021

As of 3 am CDT the cold front was draped from northeast into south
central ND, from around KGFK to KBIS. Stratus continues to
increase over south central into eastern ND along and ahead of the
front, with a few areas of fog. Low clouds were also increasing 
behind the front over northwest ND. A band of light snow was 
located over northwest ND from Portal and Crosby, southwest to 
around Williston. Clouds will continue to increase across the 
forecast area through the overnight and early morning hours. 

For today, it will be breezy and cooler with highs mainly in the
upper 30s to mid 40s. The band of light snow over northwest ND
will continue to drop southeast across the forecast area through
the day. Expect mainly trace amounts of liquid maybe a couple
hundredths, and little or no snow accumulations. There will be a
period of breezy conditions directly behind the cold front, and we
do expect breezy conditions over the south central into eastern ND
through around mid afternoon, but winds will have already dropped
off in the west and north central by then, and winds will 
continue to diminish through the late afternoon over the entire 
forecast area. Clouds will also diminish from north to south this 
afternoon as cool and very dry air spreads over the area. The low 
dewpoint air dropping into the north this afternoon will produce 
minimum relative humidities around 15 to 20 percent over the 
northern tier counties, but with much cooler temperatures and 
diminishing winds during the afternoon, when we experience the 
lowest humidities, we do not expect critical, or even near 
critical fire weather conditions. Humidities will be much higher 
over central and southern ND, even though gusty northerly winds 
will linger here into the afternoon. 

High pressure builds over the forecast area tonight with clearing
skies and light winds. This will set the stage for a very chilly
night tonight. By 12 UTC Saturday the surface ridge axis is
located from northeast ND into south central ND and central SD.
The GFS depicts a surface high just west of Aberdeen SD at 12 UTC
Saturday, which is a favorable location for cold temperatures at 
Bismarck. There does appear to be some return of moisture over 
western ND late Friday night into early Saturday morning, which 
may inhibit radiational cooling. But in general, a cold night and 
possibly a record low or two if we see ideal radiational cooling 
conditions. 

.LONG TERM...(Saturday through Thursday)
Issued at 230 AM CDT Fri Apr 23 2021

Precipitation chances Sunday and Monday highlight the Long term 
forecast period.

After a cold start, Saturday should be a pretty nice day with 
relatively light winds and quite a bit of sunshine. It will be on 
the cool side with highs generally in the upper 40s to lower 50s. 

Late Saturday night and Sunday we see the the initial warm front
lift northeast through the forecast area, ahead of the main upper
low which during this timeframe is moving onto the west coast. 
Strong isentropic upglide lifts through the forecast area at the 
same time as building upper heights downstream of the deepening 
west coast trough. There is good model consensus in bringing a 
swath of precip through the forecast area, but differences in qpf 
amounts. Again this morning, the GFS/NAM are quite a bit wetter 
than the EC/Canadian solutions. Both deterministic, as well as 
the GFS/ECMWF ensembles show the greatest potential for amounts 
greater than a tenth of an inch would be around the southern James
River Valley, and moreso into northeast South Dakota. Our given 
guidance shows a band of chance pops lifting northeast through the
forecast area with qpf amounts of around a tenth of and inch over
the south central and into the JRV, and tapering to lesser 
amounts to the north.

The main forcing moves through the Northern Plains on Monday and
there are varying solutions from the deterministic guidance. It's
a little too early anyway for specifics, but it looks like most 
of the forecast area will see a reasonable shot of precipitation 
from late Sunday night through Monday evening. As for amounts, the
ensemble GFS and ECMWF means show a good chance of amounts 
greater than a tenth of an inch, but with only meager chances of 
seeing over a half inch of liquid. Most of the precip should be 
liquid with this round on Monday, except perhaps late Monday 
evening in the north as the system is winding down.

Once this system exits the area expect mainly dry conditions with
seasonable temperatures, and perhaps a slow warming trend towards
the end of the work week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1244 PM CDT Fri Apr 23 2021

MVFR clouds today will give way to mainly VFR conditions tonight.
Abundant cloud cover will linger across much of the area today,
with MVFR ceilings expected. Clearing skies are then expected from
northwest to southeast later this afternoon through tonight.
Overnight tonight into Saturday morning expect mainly VFR
conditions. Precipitation chances today will be isolated, with
perhaps brief reductions in visibility expected. Northerly winds
are also expected today, shifting to the east southeast tonight.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Anglin
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...Anglin