Frost Advisory 6, NWS Bismarck, ND

Adams County, ND, Bottineau County, ND, Burke County, ND, Burleigh County, ND, Dickey County, ND, Divide County, ND, Dunn County, ND, Emmons County, ND, Foster County, ND, Grant County, ND, Hettinger County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McHenry County, ND, McIntosh County, ND, McKenzie County, ND, Mercer County, ND, Mountrail County, ND, Oliver County, ND, Pierce County, ND, Renville County, ND, Rolette County, ND, Sheridan County, ND, Stark County, ND, Stutsman County, ND, Wells County, ND, Williams County, ND

AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1148 AM CDT Wed Sep 21 2022

.UPDATE...
Issued at 1137 AM CDT Wed Sep 21 2022

High pressure over eastern Montana will move across western and
into central ND this afternoon and evening. Except for the
scattered clouds over the far eastern portion of the CWA, sunny
skies will prevail over the forecast area today. Breezy northwest
to north winds are expected with highs mainly in the 60s. No
changes expected for this late morning update. Updated text
products will be transmitted shortly. Frost/Freeze and winds
highlights will need to be considered for Thursday with the next
package.

UPDATE Issued at 927 AM CDT Wed Sep 21 2022

A band of clouds dropping south from Canada will brush Turtle and
James River valley this morning, with more cloud cover off to the
east. Otherwise, mostly clear this morning for most of western and
central North Dakota. Other than a few tweaks for the cloud cover,
current forecast looks good.

UPDATE Issued at 649 AM CDT Wed Sep 21 2022

Low clouds continue to stream over the Turtle Mountains and Devils
Lake Basin early this morning. There are also some scattered mid
to high clouds still skirting along the ND/SD border. Clear skies
elsewhere have allowed temperatures to drop into the 30s and 40s,
with the coldest readings in northwest North Dakota where a couple
stations have reported sub-freezing temperatures.

&&

.SHORT TERM...(Today and Tonight)
Issued at 411 AM CDT Wed Sep 21 2022

The main concern for the short term period is the potential for
widespread frost tonight.

Early morning analysis shows a broad area of surface high pressure
centered near the MT/AB/SK border intersection, with an upper level
trough digging into western Ontario. Cloud cover associated with the
cyclonic flow over north central North Dakota has been retreating
overnight. To the south, mid level frontogenesis has supported a
broken deck of mid level clouds and perhaps a few raindrops along
the ND/SD stateline, though no rain has been reported on this side
of the border. Areas that have remained mostly cloud-free overnight
have seen temperatures drop into the 40s, with a handful of 30s
across parts of northwest and west central North Dakota.

The surface high will slowly drift eastward today and tonight.
Central and eastern North Dakota will still lie within the stronger
pressure gradient through the day and will likely see gusty
northwest winds until late afternoon. Despite plentiful sunshine,
highs today will be limited to the upper 50s to mid 60s, around 5 to
10 degrees below normal for this time of year.

The heart of the surface high is forecast to reside over southern
Manitoba and the eastern half of North Dakota tonight, with a
building upper ridge to the west allowing a southeasterly return
flow to commence over far western North Dakota by Thursday morning.
Model guidance suggests increasing mid to high clouds over the
region from southwest to northeast through the night. The cloud
potential introduces some uncertainty to the low temperature
forecast for what would normally be a scenario that temperatures
fall well below consensus guidance. That said, still feel
comfortable going with the 25th percentile of NBM guidance for lows
tonight, except in the southwest where cloud cover will be greater
and winds increasing. This gives widespread lows in the 30s, with a
handful of areas falling below freezing. A Frost Advisory will very
likely be needed for much of western and central North Dakota, but
won't be issued until later today in order to avoid confusion with
the current overnight/early morning period.

.LONG TERM...(Thursday through Tuesday)
Issued at 411 AM CDT Wed Sep 21 2022

The main highlight for the long term period is the likelihood for
widespread light rain showers focused on the Thursday evening
through Friday morning timeframe.

A closed upper low that is currently near the coast of northern
California will make its way toward the Northern Rockies by Thursday
morning and progress eastward across the Northern Plains through
Friday. Strong southeast surface winds are forecast ahead of the
low's arrival on Thursday, which may approach advisory criteria in
the far southwest. The remnants of a cool dry air mass combined with
increasing clouds should once again limit highs on Thursday to the
upper 50s to mid 60s.

By late Thursday afternoon, strong synoptic scale forcing from left
exit region jet dynamics, Q-vector convergence, DCVA, and isentropic
ascent is forecast to spread across western North Dakota and
progress eastward through the night. It may take awhile for
precipitation to develop due to the dry underlying atmosphere, but
most of western and central North Dakota is very likely to see at
least some measurable rain by Friday afternoon. However, this is not
expected to be a significant rainfall by any means. While ensemble
probabilities for QPF greater than a tenth of an inch are fairly
high (at least 70 percent) for most areas, the probability for at
least half an inch of rain is no higher than 20 percent, and is
actually lower than 10 percent across southwest and south central
North Dakota. This gives us confidence that we are looking at a
widespread light rain event. One caveat is that there may be enough
instability for a few thunderstorms to convectively enhance rainfall
rates Thursday evening into Friday morning.

The center of the closed low is forecast to pass along the Canadian
border on Friday. The wrap-around cyclonic flow regime will keep
chances for light rain in the forecast for most areas on Friday, but
the bulk of the rain that does fall is still expected over the
Thursday evening to Friday morning timeframe. Before the low can
fully exit the region, a lower amplitude wave passage is being
advertised for the weekend. The associated cold front could bring a
few light showers and some gusty winds across the state, but
forecast confidence on these details is low at this time.

Ensemble consensus calls for strong ridging over the Mountain West
to spread its influence into the Northern Plains through the middle
of next week. This pattern would suggest a warming trend, which is
implied by the NBM, but there is still considerable spread in
temperature guidance. What seems more likely is that there will be
little, if any chance for precipitation after the weekend frontal
passage, and at this time, there is no indication of any potential
for measurable rain through all of next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1137 AM CDT Wed Sep 21 2022

VFR conditions are expected through the 18z TAF period.

Breezy north to northwest winds this afternoon will quickly
diminish this evening and then shift southeast as surace high
pressure moves east across the area. Strong southeast winds will
develop over western ND Thursday morning with sustained winds of
25 to 35 kts and gusts over 40 kts after 15 UTC. Precipitation
chances will move into southwest ND late in the TAF period but are
expected to remain west of KDIK through 18 UTC.

&&

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

UPDATE...TWH
SHORT TERM...Hollan
LONG TERM...Hollan
AVIATION...TWH

Hazardous Weather Outlook
National Weather Service Bismarck ND
1150 AM CDT Wed Sep 21 2022

NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051-221700-
Divide-Burke-Renville-Bottineau-Rolette-Williams-Mountrail-Ward-
McHenry-Pierce-Mercer-Oliver-McLean-Sheridan-Wells-Foster-Morton-
Burleigh-Kidder-Stutsman-Grant-Sioux-Emmons-Logan-La Moure-
McIntosh-Dickey-
1150 AM CDT Wed Sep 21 2022 /1050 AM MDT Wed Sep 21 2022/

This Hazardous Weather Outlook is for portions of north central
North Dakota, northwest North Dakota, south central North Dakota,
and southeast North Dakota.

.DAY ONE...This Afternoon and Tonight

Areas of frost are likely tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Areas of frost are likely early Thursday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

NDZ031-032-040-043-221700-
Golden Valley-Billings-Slope-Bowman-
1050 AM MDT Wed Sep 21 2022

This Hazardous Weather Outlook is for portions of southwest North
Dakota.

.DAY ONE...This Afternoon and Tonight

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Strong southeast winds are possible on Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

NDZ017-018-033-041-044-221700-
McKenzie-Dunn-Stark-Hettinger-Adams-
1150 AM CDT Wed Sep 21 2022 /1050 AM MDT Wed Sep 21 2022/

This Hazardous Weather Outlook is for portions of northwest North
Dakota and southwest North Dakota.

.DAY ONE...This Afternoon and Tonight

Areas of frost are likely tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Areas of frost are likely early Thursday morning. Strong southeast
winds are possible on Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.