Scientific Forecaster Discussion
fxus63 kbis 130341
Area forecast discussion
National Weather Service Bismarck ND
941 PM CST Tue Nov 12 2019
Issued at 939 PM CST Tue Nov 12 2019
The forecast for tonight remains on track. Cloud bases continue to
lower across western and central ND as the boundary layer
saturates. Have had a handful of reports of rain (where it is
above freezing) and snow (below freezing) the last couple of
hours, along with a few web cams showing precipitation. Will
maintain pops as is with this update.
issued at 552 PM CST Tue Nov 12 2019
The inherited forecast remains on track for this evening. I did
bump up pops a bit for a low quantitative precipitation forecast/high pop scenario this evening.
Overall forcing remains weak, though should see a widespread
dusting to half an inch of snow south of my northern two tier
counties, with some areas seeing an inch of snow through Wednesday
morning. Used a blend of the inherited forecast with latest
NAM/href guidance. Will keep the precip type as all snow with time
height cross sections and BUFKIT showing a well saturated layer
during peak forcing. Do see loss of ice on the backside, but this
is also when forcing is pretty much gone.
Short term...(this evening through wednesday)
issued at 140 PM CST Tue Nov 12 2019
Light snow is expected to develop across most of western and
central North Dakota tonight, before ending later tomorrow
Current surface weather analysis depicts a warm front across south
central North Dakota, with temperatures already in the lower 30s
across southwestern North Dakota. This warmer air will be short-
lived, as a cold front dives southward out of southern
Saskatchewan and Manitoba this evening and moves across North
Dakota tonight. The 12z Euro/GFS/NAM and the latest cam model
guidance depict an area of light snow behind the cold front,
affecting almost all of western and central North Dakota tonight
into early tomorrow morning. Overall synoptic scale and mesoscale
forcing looks rather weak, so significant accumulations are not
expected. In fact, the latest nbm/wpc quantitative precipitation forecast amounts are very low,
giving most areas only a dusting to one inch of snow. This seems
reasonable given the low snowfall rates that are expected, along
with the rather short duration of falling snow.
Tomorrow is shaping up to be a bit colder than today, with highs
mainly in the 20s. Southwest North Dakota will be the warmest,
with highs around 30 degrees. Although forecast NAM bufr soundings
depict a perfect setup for lake effect snow showers downwind of
Lake Sakakawea tomorrow, it appears the air moving over the lake
will not be cold enough to produce precipitation... as the lake
surface temperatures are most likely in the mid to upper 30s.
Nevertheless, a Few Lake effect clouds may be possible downwind of
Lake Sakakawea tomorrow.
Long term...(wednesday night through tuesday)
issued at 140 PM CST Tue Nov 12 2019
The long term forecast is highlighted by warmer temperatures and
an overall drier weather pattern. Chances for precipitation will
return this weekend.
The 12z GFS/Euro both depict a prolonged period of mainly
northwest flow aloft from Wednesday night through Friday morning,
downstream of a ridge located across western portions of the
Continental U.S.. zero quantitative precipitation forecast is being produced during this time period, as
there are no shortwave troughs or impulses embedded within the
northwest flow. At the surface, high pressure is dominant. Sinking
motion will lead to clearing skies on Wednesday, with some
sunshine expected on Thursday as well. In fact, the latest blend
of model guidance suggests highs in the upper 30s to lower 40s
across western and central North Dakota on Thursday, with mid 40s
possible across southwestern North Dakota on Friday.
Saturday through Monday will likely feature widespread highs in
the 40s along with partly to mostly cloudy skies. There will be
several chances for rain or snow during this time period as a few
shortwaves move across the area. Current quantitative precipitation forecast amounts are quite
low, with limited precipitation chances. There are currently no
significant storm systems in the foreseeable future!
Aviation...(for the 00z tafs through 00z Wednesday evening)
Issued at 552 PM CST Tue Nov 12 2019
VFR cigs will lower to MVFR this evening and tonight as cloud
cover thickens and lowers across western and central North Dakota
ahead and along an approaching cold front. An area of light snow
will accompany the front tonight, with all taf sites likely being
affected. An occasional MVFR/IFR vis possible, but overall the
snow is expected to be light. Accumulations swill also be light,
generally just a trace to less than one inch. VFR conditions
redevelop by Wednesday afternoon.