283 
FXUS63 KBIS 151201
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
601 AM CST Tue Jan 15 2019

.UPDATE...
Issued at 600 AM CST Tue Jan 15 2019

Allowed the dense fog advisory to expire at 6AM CST as latest 
fog/stratus loop, surface visibility observations, and webcams 
continue to show improvement. Next round of stratus now crossing 
into northwest North Dakota along and behind a cold front. The 
stratus and cold front will quickly move southeast this morning, 
resulting in a fairly quick return to cloudy conditions. Current 
forecast is on track.

&&

.SHORT TERM...(Today and tonight)
Issued at 259 AM CST Tue Jan 15 2019

Latest fog/stratus imagery loop and surface observations/webcams
still support a dense fog advisory portions of south central
through the James River Valley. Westerly winds in the boundary
layer continues to advect drier air into the surface-925mb layer 
per RAP BUFKIT soundings. This trend will erode the stratus/fog 
regime from west to east, reaching Jamestown by around 12z/6AM 
CST. Will cancel counties from the dense fog advisory as they 
become warranted, but as of now the dense fog advisory remains in
good standing. A cold front now into southern Saskatchewan with 
another area of stratus will reach the northern border 12z-13z 
/6AM-7AM CST, then continue to quickly push south, reaching 
Bismarck 15z-17z/9AM-11AM CST. Utilized a blend of the RAP/NBM 
sky grids which have initialized well with the current satellite 
imagery. Also replaced Forecast Builder winds with CONSMOS, which 
were more in line with the RAP BUFKIT mixed layer winds around 
25kt, especially over the James River Valley. Expecting a dry cold
frontal passage with this event, with an increase in clouds and 
wind as mentioned above. Cold air advection dominates today into 
early tonight before becoming mostly neutral by Wednesday morning.
Highs today will be in the 20s to around 30F in the far 
southwest. 

For tonight, northerly winds will veer northeast then southeast 
as the bulk of the stratus shifts into the southwest. That will 
leave partly cloudy to mostly clear conditions elsewhere with 
very cold temperatures along and east of the Missouri River. 
Expect low temperatures along and east of the Missouri River
ranging from zero to 11 below zero by the time you reach the 
Turtle Mountains. On the flip side will be southwest ND where 
lows will be in the mid teens above zero. 

.LONG TERM...(Wednesday through Monday)
Issued at 259 AM CST Tue Jan 15 2019

A tranquil Wednesday with partly to mostly cloudy conditions. A
mid/upper level shortwave will shift from the intermountain west
into eastern Montana and northwestern South Dakota Wednesday.
Weak reflection of surface low pressure in southwest ND will aid
in low level warm air advection, creating a distinct temperature
gradient from southwest to northeast. Expect highs around 30F
southwest to the lower single digits above zero in the Turtle 
Mountains. 

A 1040mb surface high pressure will begin to make its move
southeast from Alberta and Saskatchewan Wednesday night through 
Friday. This will represent the leading edge of the arctic air and
dangerous wind chills that are forecast Friday through Sunday.
A slight chance of snow exists Thursday as the colder air pushes
from north to south, but amounts are meager, perhaps a tenth or
two. A better chance of snow develops over eastern Montana and
spreads east Thursday night and Friday, favoring southwest and
south central ND. Snowfall accumulations as of now are highest in
southwest ND, where around two inches are anticipated. South 
central may see up to one inch. The GFS/ECMWF are similar with 
their solutions.

Main highlight Thursday night through Sunday morning continues to
be the dangerous wind chills. Wind chills as low as 35 to 40 
below zero at times still on track each night and into the 
morning hours, from Thursday through Sunday.

Beginning Monday and through most of next week, a parade of 
clipper type systems can be expected. The first one is forecast to
push through Monday, then possibly a more significant clipper 
Wednesday through Thursday. 

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 521 AM CST Tue Jan 15 2019

LIFR/IFR cigs at KJMS will continue until 14z, briefly becoming 
vfr before returning to ifr status from 16z-23z. A cold front will
push from north to south today, with stratus and ifr/mvfr cigs
developing right behind the front. This is the case at KISN/KMOT 
where cigs will deteriorate to ifr by taf issuance and remain
there until 21z. KDIK/KBIS will reach mvfr/ifr status by 16z and
continue through 06z at KBIS, but likely remaining at mvfr/ifr
conditions for KDIK through the taf period. Brisk northwest winds
will ensue today ranging between 15kt and 28kt behind the frontal
passage.


&&

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

$$

UPDATE...KS
SHORT TERM...KS 
LONG TERM...KS 
AVIATION...KS