Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 180234
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
934 PM CDT Wed May 17 2017

.UPDATE...
Issued at 933 PM CDT Wed May 17 2017

Cloud cover has been a bit reluctant to dissipate this evening,
but latest high-res guidance starts working the clouds out of the
area later this evening and overnight. Current frost headlines
remain in good shape.

UPDATE Issued at 633 PM CDT Wed May 17 2017

No major changes need with this update. Just blended the latest
observations to the going forecast.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 246 PM CDT Wed May 17 2017

Frost Advisory tonight for western and most of central North Dakota.

Forecast highlights in the short term period will be cooler
temperatures with frost tonight, and mainly dry conditions.

Currently, a large scale upper level low was over the Intermountain
West region of Utah/Idaho, with another shortwave low moving
northeastward through the central Plains. A surface low co-located
with the central Plains upper low was associated with showers and
thunderstorms from the central Plains through Minnesota today.
Meanwhile a large surface high pressure system was centered over
central Canada, with its dry northeast wind flow dominating North
Dakota this afternoon.

Tonight the dry high pressure center moves south, with the dry air
with dewpoints in the 30s moving south into North Dakota. Clearing
skies, light northeast/north winds and dry air moving in will allow
temperatures to drop into the low to mid 30s over western and most
of central North Dakota. The James Valley may be able to escape the
frost for tonight, with expected lows in the upper 30s/lower 40s.

Mostly sunny but cool on Thursday, with highs in the mid to upper
50s.

.LONG TERM...(Thursday night through Wednesday)
Issued at 246 PM CDT Wed May 17 2017

Thursday night and Friday: The large upper level low is forecast to
be over the 4-corners area, with the upper Mississippi Valley low
now an open wave and moving quickly into the Canadian maritimes. At
the surface, dry high pressure dominates the Northern Plains,
keeping an easterly/northeasterly wind flow across North Dakota,
with mainly clear skies. Another cool night Thursday night/Friday
morning, with morning lows forecast in the low to mid 30s. This will
likely require another frost advisory and/or freeze warning for much
of western and central North Dakota. During the day Friday the
surface high moves east into the Great Lakes area, allowing a
southeasterly wind flow over our area. Meanwhile the 4-corners upper
level low begins its move northeastward into the central Plains.

Friday night and Saturday: The upper low continues its northeastward
progression reaching into eastern North Dakota Friday night and
moving towards Lake Superior Saturday night. Model differences in
today`s runs with discrepancies regarding how far west in North
Dakota the rain showers may reach associated with this system.
However, ensemble means, the NAM, and ECMWF agree on bringing
showers into southwestern and southern ND despite the operational
GFS, which would trend on the dry side for southwestern and central
ND. Thus model consensus favors rain showers Friday night across
southern ND and better chances Saturday in central ND.

Saturday night through Wednesday: Following the exiting upper level
low, the mean upper flow becomes northwesterly across North Dakota,
with a narrow, meridional ridge over the west coast of North
America. The models are indicating a significant shortwave low
moving south across central Canada and moving through the Dakotas
Monday/Monday night, bringing chances of showers to our area. This
shortwave then merges with a Hudson Bay low, and begins retrograding
back westward to the Great Lakes. This large low encompasses the
eastern 2/3 of North America, keeping a cool, cyclonic flow over the
Northern Plains with chances of showers off and on through the
remainder of the long term forecast period. High temperatures should
be mainly in the 60s with lows mainly in the 40s for this time
period.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 633 PM CDT Wed May 17 2017

Lower clouds floating around western and central North Dakota will
continue to move out this evening and into the overnight hours.
Breezy north to north northeast winds will slowly diminish from
west to east as we approach sunset, except over KJMS, where
breezy conditions will linger through the overnight hours. VFR
conditions are anticipated through the forecast period.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 1 AM CDT /midnight MDT/ to 9 AM CDT /8 AM
MDT/ Thursday for NDZ001>005-009>013-017>023-031>036-040>047-050.

&&

$$

UPDATE...JJS
SHORT TERM...JV
LONG TERM...JV
AVIATION...ZH



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