Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 190933
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
333 AM CST Mon Feb 19 2018

.SYNOPSIS...
Issued at 328 AM CST Mon Feb 19 2018

H5 analysis this evening had a closed low over Hudson Bay. A
strong shortwave was located over northeastern Washington state
with a trough extending southwest to just off the coast of Oregon.
Downstream of this trough, weak lead shortwaves were noted from
northern Nevada into northeastern Wyoming. A strong cold front
pushed through the forecast area Sunday afternoon into the early
evening hours. Strong northerly winds have developed behind the
front which was now located from extreme southeastern Nebraska to
far southwestern Kansas. In addition to wind and cold
temperatures, light snow has developed across western and north
central Nebraska overnight with radar over shooting most of this,
as little or no returns were showing up on radar overnight.
Overnight temperatures were cold with readings ranging from the
single digits in the north to middle teens in the south.

&&

.SHORT TERM...(Today and tonight)
Issued at 328 AM CST Mon Feb 19 2018

In the short term, the ongoing winter weather event is the main
forecast concern over the next 24 hours. Cross sections taken
perpendicular to the h5 flow indicate meager lift in the dendritic
zone across southern portions of the forecast area this morning.
Will allow a mention of light snow in the southern forecast area
through sunrise to account for this. This lift diminishes
significantly by mid morning, so will go with a dry forecast
across southern and southeastern portions of the forecast area
through this afternoon. Further north, weak lift in the dendritic
zone will continue today, especially across northwestern portions
of the forecast area and will retain high pops in these areas.
However, QPF`s will be light, so not expecting much in the way of
snow accumulations. The main upper level trough of low pressure
will cross the intermountain west today, approaching the northern
Rockies tonight. Mid level lift will increase downstream of this
approaching feature this evening. Increased mid level lift and
increased mid level moisture will lead to the development of snow
across the forecast area tonight. Snow, possibly heavy at times,
will develop from the northeastern Nebraska Panhandle, east across
northern Nebraska. Looking at tonights model runs, decided to
scale back snow accumulations slightly, however the forecast
remains in the 6 to 9 inch range for Sheridan and western Cherry
county. Still wouldn`t be surprised if we saw some higher amounts
in the Pine Ridge as the surface wind field favors some local
enhancement. Further east, and south of the warning, forecast snow
accumulations of 2 to 5 inches are still on track, with 1 to 2
inches expected along the I-80 corridor into the eastern
sandhills. No changes are expected to be made to ongoing winter
weather headlines.

.LONG TERM...(Tuesday through Sunday)
Issued at 328 AM CST Mon Feb 19 2018

Southwest flow aloft remains through the week with an Intermountain
West trough, Hudson Bay low, and a Bermuda high. At the surface, a
1040mb+ high scoots across the northern Plains midweek and is
replaced by a late week lee side low emerging onto the southern
Plains.

Tuesday is still shaping up to be a brutally cold day with H85 temps
near -20C and blustery northwest winds. Highs range from the single
digits far NW to upper teens SW. The combination of dry air and
isentropic downglide will end snow chances by afternoon. Made little
change to overnight lows as weak WAA aloft is countered by light
winds, partly/mostly clear conditions, and a fresh snowpack (NW
mainly). With lows from -10 to -15F in Cherry and Sheridan counties,
wind chill criteria could easily be met. Temps moderate somewhat
into the mid/upper 20s on Wednesday with the help of return flow and
sunshine.

Precip chances increase Thursday as a shortwave crosses the northern
Plains. Overall, precip appears light with snowfall amounts up to
one inch, most of which will fall in a 3 to 6 hour period of strong
lift and decent moisture. Forecast soundings show the temp profile
staying on the warm side of the DGZ for much of the event, which
would likely result in lower SLR`s. Another wave passes by on
Friday, but it has weaker lift/fgen and keeps the best moisture in
the low levels. A more pronounced wave then comes through on
Saturday, but the best moisture and forcing are shifted east of the
forecast area. With H85 temps around -3C and sfc temps reaching 40F
for most spots, any precip would be liquid or mixed.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 529 PM CST Sun Feb 18 2018

Stratus with MVFR cigs and areas of light snow are over
northwestern Nebraska. These cigs will move to the southeast over
night into southern Nebraska. Strong north winds will continue
over western Nebraska through tonight.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until noon CST /11 AM MST/ Tuesday for
NEZ004-094.

Winter Weather Advisory from 6 PM CST /5 PM MST/ this evening to
noon CST /11 AM MST/ Tuesday for NEZ005>010-022>025.

&&

$$

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Snively
AVIATION...Power



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