Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 261506

Area Forecast Discussion
National Weather Service Bismarck ND
1006 AM CDT Wed Apr 26 2017

Issued at 1006 AM CDT Wed Apr 26 2017

Regional radar mosaic shows the main band of precipitation
extending from northeast South Dakota and southeast North Dakota
into western Minnesota. Reports indicate between 1 and 3 inches of
snow has fallen so far with the highest report of 2.5 inches 4ESE
of La Moure. The latest RAP, HRRR and NAM suggest a brief decrease
in the precipitation intensity late this morning before it
potentially increases again this afternoon. Overall things look
on track and only made small adjustments to the going forecast.

UPDATE Issued at 647 AM CDT Wed Apr 26 2017

Recent RAP and HRRR simulations have shifted the core of QPF ever
so slightly southward in the southern James River valley, which is
in line with radar trends that also suggest the western gradient
of precipitation needs to be tightened a bit. We therefore chose
to lower snowfall amounts in the Jamestown area with this update.
However, those same RAP and HRRR iterations along with the 06 UTC
NAM and GFS continue to strongly support 3-6 inches of snow today
in Dickey and LaMoure Counties. That GFS cycle was a bit further
northwest with its QPF axis than the rest of the guidance, though.
Otherwise, we did increase the mention of light freezing rain on
the northwest side of the precipitation shield from Jamestown to
Ashley this morning based on early DOT reports and a lack of deep-
layer saturation into the ice crystal production zone in forecast
soundings on the fringe of the stronger synoptic-scale forcing.


.SHORT TERM...(Today and tonight)
Issued at 244 AM CDT Wed Apr 26 2017

The main weather impact is snow setting up across the far
southern James River Valley this morning. Forecast soundings indicate
large scale ascent occurring within the dendritic growth zone
(-12c to -20C) along with steep mid level (700mb- 600mb) lapse
rates through much of the day today. This could produce snowfall
amounts between 3 and 6 inches by this afternoon across Dickey and
LaMoure Counties.

There are two factors that could limit snow totals. First,
freezing rain is possible early this morning before the column
becomes completely saturated. Second, as temperatures rise this
afternoon snow may mix with rain and surface temperatures may rise
briefly above freezing. This may make reaching 6 inches difficult,
but the combination of hazards still warrants heightened
awareness and caution.

The rest of forecast area will remain dry and cold with sky
conditions improving from mostly cloudy to mostly sunny, from west
to east in the afternoon. Highs will range from the upper 30s
Turtle Mountains south into the James River Valley to the 40s

.LONG TERM...(Thursday through Tuesday)
Issued at 244 AM CDT Wed Apr 26 2017

Overall a dry and cool pattern continues through Friday, with
temperatures moderating into the 50s Saturday through Tuesday. The
jet stream remains south of North Dakota which should lead to a
fairly tranquil pattern through Sunday. Monday and Tuesday the
pattern looks to become active again as the northern stream
eventually pushes a cold front through by the end of the extended


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 647 AM CDT Wed Apr 26 2017

MVFR and local IFR ceilings with snow and areas of light freezing
rain will impact the southern James River valley today, but we are
not confident in impacts at KJMS on the northwest side of the main
precipitation shield. Otherwise, MVFR stratus in southwestern ND
is forecast to lift by midday. By tonight mainly VFR conditions
are forecast as low pressure aloft slowly moves out of the area.


Winter Weather Advisory until 7 PM CDT this evening for NDZ048-



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