393
FXUS63 KBIS 220257
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
957 PM CDT Tue May 21 2024

.KEY MESSAGES...

- Areas of frost are expected to develop across western and
  parts of central North Dakota tonight into Wednesday morning.
  Therefore, a Frost Advisory has been issued.

- 60 to 80 percent chance of rain Thursday afternoon through
  Friday morning for most locations along and south of highway
  200. 30 to 50 percent chance of rain for locations further
  north.

- Unseasonably cold Thursday night through Friday night, with
  lows in the 30s and highs on Friday only in the upper 40s to
  upper 50s.

&&

.UPDATE...
Issued at 952 PM CDT Tue May 21 2024

There are still a few lingering showers across the north
central and a few more over the far south central. Thus, we did
elect to expand the mention of isolated showers across these
areas for another hour. The Frost Advisory still looks to be on
track for the western half of the forecast area where we should
see a clearing sky and light winds. Expect lows to potentially
dip into the low to mid 30s across most of the west, especially
the northwest.

UPDATE
Issued at 624 PM CDT Tue May 21 2024

Isolated showers continue to diminish as we start to lose
daytime heating. Winds will also continue to diminish. No major
changes were needed for this update other than to blend in the
latest observations to the forecast.

&&

.DISCUSSION...
Issued at 221 PM CDT Tue May 21 2024

Presently, strong surface low pressure has moved into central
Minnesota. However, with a very tight and narrow gradient on the
western side of the low, few impacts have been observed in the
forecast area. Breezy conditions have been observed in the
southern James River Valley of ND, while light rain has only made
it into far eastern Dickey County. Elsewhere, thick diurnal cu
has produced isolated showers that should rapidly diminish this
evening.

For tonight, as surface high pressure nudges into the state, winds
are expected to go light in the west while skies are likely to
clear. This will result in favorable radiational cooling
especially in western North Dakota. As a result, lows are
forecast to drop into the mid 30s for most of the western third
of the state generating favorable conditions for frost
formation. Therefore, opted to issue a Frost Advisory for all
counties along and west of Highway 83, except those in the south
central including Burleigh, Sioux, and Emmons counties.

For Wednesday, overall expect mostly dry conditions along with
mostly sunny skies. Highs should range from the 60s to around
70 in the far south. That said, a few showers may develop in
the southwest in the afternoon. Low pressure will then begin to
organize as it propagates across the Northern Plains Wednesday
night through Friday. The exact path of this system remains a
little uncertain, although a 60 to 80 percent chance of rain
persists across at least the southern two thirds of the state,
with lesser chances further north. There may be a few embedded
thundershowers as well, although the threat for strong to severe
thunderstorms looks to be very low at this time. Periodic
showers and thunderstorms are then possible the latter half of
the weekend and into early next week.

Overall, expect below average temperatures through at least the
weekend. Though most days, temperatures will be seasonably cool
(within 5 to 10 degrees of average). However, temperatures
Thursday night through Friday look unseasonably cool with lows
mostly in the 30s and highs Friday mostly in the upper 40s to
upper 50s. More widespread frost may develop Friday night as
lows potentially drop into the low to mid 30s across the entire
forecast area.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 624 PM CDT Tue May 21 2024

VFR conditions are expected at all sites through the period. An
isolated shower or two remains possible through sunset but they
will be more miss than hit. Winds across the east will continue
to diminish this evening before they become breezy again
Wednesday afternoon out of the northwest.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 3 AM CDT /2 AM MDT/ to 9 AM CDT /8 AM MDT/
Wednesday for NDZ001>003-009>011-017>021-031>034-040>044.

&&

$$

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