Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/03/18

Area Forecast Discussion

National Weather Service Bismarck ND

 933 PM CST Fri Mar 2 2018

.UPDATE...

Issued at 933 PM CST Fri Mar 2 2018

No major changes needed with this update. Low level clouds forming
in earnest as advertised across western ND. Will maintain fog and
patchy freezing drizzle as well for late this evening and for the
overnight.


UPDATE
Issued at 645 PM CST Fri Mar 2 2018

Forecast for tonight remains on track. Models continue to portray
a threat of freezing drizzle across western ND later this evening
and overnight as boundary layer moisture increases under an
easterly upslope flow regime, and as a mid level S/WV lifts
northeast across the region along with increasing divergence
aloft. Fog was added to the forecast, with the highest probability
of occurrence over the southwest as advertised by the HRRR and
ConsShort.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 347 PM CST Fri Mar 2 2018

Currently, an upper level low was over the Pacific Northwest, with
southwest flow aloft across the Rockies into the Dakotas. Meanwhile
a surface Colorado Low continued to develop, with a large surface
circulation reaching across the Dakotas. The easterly upslope flow
will bring a chance of fog and/or some light freezing drizzle to far
western North Dakota - mainly after midnight. There will be small
chances of light snow, light freezing drizzle, or light freezing
across the northern tier of counties on Saturday.

.LONG TERM...(Saturday night through Friday)
Issued at 347 PM CST Fri Mar 2 2018

The highlight of the long term will be the possible winter storm
late this weekend into early next week.

Saturday night and Sunday, the large upper low crosses the Rockies,
and the surface Colorado low deepens and moves east into the central
plains of NE/KS. Sunday night into Monday the upper and surface lows
become stacked, intensifying over eastern SD, then develop farther
east into Iowa by Tuesday morning.

This complicated storm system involves plenty of warm, moist gulf
moisture moving north across the plains, reaching the eastern and
central Dakotas Saturday night through Sunday night, before the
colder (below freezing at h850) air finally invades into south
central North Dakota late Sunday night. Latest model consensus
brings plenty of precipitation to our state. We are looking at
liquid water equivalent amounts of at least 0.5 inches to 1.25
inches. The main forecast problem is what form the precipitation
will take (rain, freezing rain, snow). This, in turn, will affect
forecast snowfall totals.

Sunday morning it appears that chances of freezing drizzle will
spread across western and north central North Dakota, though amounts
should be light. Sunday afternoon should be the beginning of high
chances of precipitation. The warm gulf air moving into the eastern
Dakotas should bring mainly rain with temperatures rising into the
mid and upper 30s, with chances of freezing drizzle or light snow in
the western part of the state.

Even Sunday night we should still see the effects of the warm air
intrusion, with snow west, rain changing to snow north central, and
a mix of rain and snow south central, with mainly rain continuing in
the James River Valley.

On Monday, western and most areas of central ND should see snow,
with the James Valley changing from rain to freezing rain to snow.
Monday night the snow continues, not beginning to taper off until
Tuesday afternoon.

Regarding winds: northwest winds begin to pick up Sunday afternoon
and night, with blowing and drifting snow becoming hazards in the
wets and north central. On Monday, northerly winds are gusty, but
especially strong in the southwest. Falling snow, and blowing and
drifting snow will be the main hazards across all of western and
central ND Monday through Tuesday morning. Would not be surprised to
see blizzard conditions develop, especially in southwestern ND late
Sunday night and Monday with sustained northwest winds expected to
reach 25 to 35 mph with gusts to 45 mph.

Regarding snow totals: There is a high probability that snow totals
will exceed 8 inches in the west and north central, with high
probability that the south central may exceed 4 inches. Higher
amounts are possible, but there is a lot of uncertainty in precip
type and timing of rain changing to snow.

After the large winter storm exits our area to the east, ridging
develops over the Rockies, with mainly quiet weather with highs
mainly in the 20s and lows mainly zero to 15 above.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)

Issued at 645 PM CST Fri Mar 2 2018

MVFR ceilings currently across the west early this evening. As we
move through this evening, ceilings over western ND lower to
IFR/LIFR and will become widespread. Some uncertainty how far east
into central ND the stratus will develop into tonight. Areas of
fog with a chance of patchy freezing drizzle also possible west
tonight, though for now left this out of the forecast with some
uncertainty still. Low clouds will expand over all terminals
Saturday morning/afternoon west to east.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Sunday afternoon through Tuesday morning
for NDZ001>005-009>013-017>023-031>036-040>046.

&&

$$

UPDATE...NH
SHORT TERM...JV
LONG TERM...JV
AVIATION...NH