National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KBIS 182344
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
644 PM CDT Sun Apr 18 2021

.UPDATE...
Issued at 644 PM CDT Sun Apr 18 2021

Some light radar returns are still seen in southwest North Dakota
from the Bowman radar, but it looks like the light precip has just
about ended this evening as the baroclinic zone continues to drop
south. Otherwise, breezy and cloudy conditions will continue
through the evening, with 2330 UTC temperatures only in the 30s
across the forecast area. No changes needed with this update.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 207 PM CDT Sun Apr 18 2021

Seasonably cool with a north wind and periodic chances for light
rain or snow showers highlight the short term period.

This evening, a low level baroclinic zone will be draped from
central Montana through southwest North Dakota into northern South
Dakota, sloped up in the atmosphere behind a surface cold front
which is now well into South Dakota. Light snow is possible in
the far southwest portion of the state tonight along this
baroclinic zone, before it too finally exits south.

Monday will begin a period early this week of cyclonic flow aloft
with multiple embedded impulses delivering seasonably cool air,
breezy northerly winds, and chances for rain or snow showers.
Highs in the upper 30s to around 40 and lows around 20 can be
expected both Monday and Tuesday. Broad areas of slight chance
POPs were used given uncertainty of precipitation at any one
location under the unfocused ascent pattern.

.LONG TERM...(Tuesday night through Sunday)
Issued at 207 PM CDT Sun Apr 18 2021

Warmer and dry mid-week. No major concerns to highlight in the
longer term forecast period.

Mid-week, height rises aloft with a building ridge returns warmer
and dry conditions. Good agreement exists in temperatures between
ensembles/MOS/NBM where highs generally in the 50s can be
expected Wednesday and 60s on Thursday. Minimum relative humidity
should drop below 20 percent in areas of the west and central
during this period as well, though at this time it looks like a
relatively diffuse surface pressure pattern should keep winds on
the lighter end for fire weather concerns. A weak cold front is
expected to cross the region Friday, though the lack of
atmospheric moisture and the progressive forcing keeps the current
forecast very low on the QPF side. By this weekend guidance
begins to diverge more but the mean trend is to return
temperatures closer to normal in that time frame as most guidance
shows a broad ridge taking over the central CONUS.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 644 PM CDT Sun Apr 18 2021

VFR conditions expected at all terminals through the TAF cycle.
Breezy northerly winds will subside some overnight with low VFR
ceilings partially clearing from the north. On Monday, expect
northwest winds to become breezy, with increasing clouds and a
chance of rain and snow showers in western North Dakota after 18Z.
Not included at any terminal with this update due to low
confidence in occurrence.

&&

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

$$

UPDATE...MJ
SHORT TERM...AE
LONG TERM...AE
AVIATION...MJ