500
FXUS63 KBIS 182346
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
646 PM CDT Tue Jun 18 2024

.KEY MESSAGES...

- Scattered light rain showers this evening in the northwest
  and south central.

- Below average temperatures tonight, with frost likely in the
  west. Some temperatures below freezing can not be be ruled
  out in southwest North Dakota. Seasonably cool temperatures
  continue through Saturday.

- Frost Advisory for western and portions of south central
  North Dakota tonight.

- Mostly dry Wednesday, then chances for showers and
  thunderstorms return late Thursday through Saturday.

&&

.UPDATE...
Issued at 644 PM CDT Tue Jun 18 2024

Updated for Aviation discussion.

UPDATE
Issued at 526 PM CDT Tue Jun 18 2024

The forecast for the remainder of this afternoon and evening
remains on track. Isolated to scattered showers linger across
the local area with a S/WV mid level trough swinging east
through the Northern Plains. Still expect clearing in the wave`s
wake west to east tonight, along with lowering dewpoint temps
falling into the 30s, increasing the probability for frost
development. Thus headlines remain valid.

&&

.DISCUSSION...
Issued at 255 PM CDT Tue Jun 18 2024

Currently a cold front is moving through the northwestern part
of the state, turning winds to the north. A big surface low
pressure is sitting over western Minnesota. Low stratus and
cumulus can be found across the area with light rain falling in
the northwest, and the south central. Aloft the CONUS is split
in half with a large trough over the west, and a ridge over the
Eastern Seaboard. The trough axis currently sits in central
Montana. Once that moves through later this evening the chance
of rain will be done, and skies will clear out.

A Frost Advisory is in effect tonight in the western part of
the state, and portions of the south central. With the clear
skies and calm winds behind the cold front, temperatures will
likely drop to the mid 30s and possibly to freezing, especially
in the lower valleys. This is at least 10 degrees below average.
The advisory runs from 07 to 13z.

Wednesday will be dry with a surface high pressure centered over
the Dakotas and quasi-zonal flow aloft. High temperatures will
also remain below average in the lower 70s. Thursday flow aloft
starts to turn southwest as the next trough forms over
California. Thursday will only be slightly warmer with that
southwest flow. A near Colorado Low at the surface will form
from this trough Thursday night, moving in Friday morning.
Meanwhile a clipper system out of Canada will slide across the
north. This will lead to almost two rounds of rain. First across
the south and east, then across the west and north through
Saturday.

The rest of the forecast will be drier and warmer. A quick ridge
moves through Sunday with warmer temperatures, back into the
upper 70s and mid 80s. Monday after the ridge moves through the
south could get near 90 with the north nearing 80 under zonal
flow.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 645 PM CDT Tue Jun 18 2024

MVFR-IFR cigs this evening with lingering light rain showers.
Cigs will lift and the sky will clear this evening into the
overnight with winds remaining north/northwesterly.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 2 AM CDT /1 AM MDT/ to 8 AM CDT /7 AM MDT/
Wednesday for NDZ001-002-009-010-017>020-031>034-040>044.

&&

$$

UPDATE...NH
DISCUSSION...Smith
AVIATION...Smith