Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 210232

Area Forecast Discussion
National Weather Service Bismarck ND
932 PM CDT Sat May 20 2017

Issued at 929 PM CDT Sat May 20 2017

Quick update for observed trends through 02 UTC. Again, no change
to the Frost Advisory for tonight through Sunday morning, as
areas already in the Advisory based on satellite trends are most
likely to have the most efficient radiational cooling with the
thinnest cloud cover.

UPDATE Issued at 649 PM CDT Sat May 20 2017

Little change other than to blend to observed trends through 23
UTC. No change to the Frost Advisory area is warranted at this
time based on cloud cover/satellite trends as the deep low across
northern Iowa will propagate into southern Minnesota tonight.


.SHORT TERM...(This evening through Sunday)
Issued at 328 PM CDT Sat May 20 2017

A few highlights in the short term period: A frost advisory for
portions of southwest and south central ND tonight into early Sunday
morning; rainshowers continuing over the James River Valley tonight
into Sunday morning; then isolated to scattered thunderstorms mainly
across the west Sunday afternoon and evening.
Thunderstorm parameters suggest nothing severe at this time.

Per water vapor imagery, the forecast in the short term and into the
early portion of the extended will be dominated by the slow movement
of a closed mid/upper level low circulating over central Nebraska
this afternoon.

In the near term, rain has begun in Ellendale as a shortwave per
NAM/GFS pivots around the upper low and into the James River Valley.
Large scale ascent increases this evening per NAM/GFS and have
likely (60 to 70) pops developing from Carrington to Ashley, with
categorical pops (90 to 100) in LaMoure and Dickey counties.
The precipitation shield does show signs of edging back into far
eastern Wells/Burleigh/Emmons counties. Have isolated showers
mentioned here through Saturday evening.

The upper low is forecast to move into central Minnesota Sunday
morning, then into southern Ontario Sunday evening. This keeps
chances for rain showers within the James River Valley Sunday
morning before exiting by early afternoon.

Another shortwave this afternoon seen circulating just south of
Yellowknife/Northwest Territories of Canada, becomes entrained
within the aforementioned larger mid/upper low circulation Sunday
through Monday. In doing so, the shortwave and an accompanied weak
surface cold front dive into eastern Montana and the western
Dakotas Sunday night through Monday. Enough instability with this
feature to produce isolated to scattered showers and thunderstorms
primarily in the west Sunday afternoon and evening. Highs Sunday
in the 60s across western/central ND.

.LONG TERM...(Sunday night through Saturday)
Issued at 328 PM CDT Sat May 20 2017

Unsettled at the beginning and at the end of the long term, with
a brief dry and warm period in the middle. Chances for rainshowers
and thunderstorms continue Sunday night and Monday, with
thunderstorm chances greatest in the southwest and into south
central. Showers dwindle and end Monday night with a transitory
ridge Tuesday/Wednesday. Southerly winds increase Wednesday ahead
of our next shortwave trough and associated surface cold front.
Highs Wednesday rise well into the 70s. The cold front slides
through Wednesday night and Thursday with a slight chance of
showers. Thereafter, models agree that in some form, a trough
will reside over the northern high plains Thursday through
Saturday with a chance of showers and thunderstorms continuing
through the period.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 929 PM CDT Sat May 20 2017

IFR conditions will develop across the James River Valley tonight
in stratus and rain, including KJMS. Conditions will improve to
MVFR late Sunday morning. VFR conditions are forecast elsewhere
for the 00 UTC TAF cycle for western and central North Dakota.
Scattered thunderstorms are expected across western North Dakota
Sunday afternoon and evening. Confidence in impacts to the
terminals is too low to include in the TAFs at this time.


Frost Advisory from 1 AM CDT /midnight MDT/ to 8 AM CDT /7 AM
MDT/ Sunday for NDZ018>020-033-034-040>044.



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