Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 042341

Area Forecast Discussion
National Weather Service North Platte NE
541 PM CST Sun Dec 4 2016

.SHORT TERM...(This evening through Monday)
Issued at 332 PM CST Sun Dec 4 2016

After a seasonally warm afternoon with highs into the 40s and even a
few low 50s, expect the mild conditions to continue overnight.
Mid/high clouds on the increase which will help hold temps
overnight in the 20s, about 10 to 15 degrees above climo.

Tomorrow a cold front will arrive to the northwest CWA in the
morning then push across the area during the day. This will make
temps a little tricky as strong cold air advection behind the front
will halt temps, and likely falling in the afternoon. Ahead of the
front compressional heating should be enough to return temps to the
lower 50s.

Behind the front mid level moisture is limited and expect most areas
to remain dry, however some convergence downwind of the pine ridge
may be enough for some light precip. Temps falling in the 30s with
expected precip type be primarily snow, although can not rule out an
initial rain/snow mix but that should be short lived.

.LONG TERM...(Monday night through Sunday)
Issued at 332 PM CST Sun Dec 4 2016

The model consensus indicates a relatively weak initial push of
arctic air Tuesday with winds becoming light and variable Tuesday
afternoon and east and northeast Tuesday night. This would support
upslope moisture pooling across Swrn Neb.

The model consensus has tightened up with the morning model runs and
north show a close h700mb circulation across Wcntrl KS Wednesday
morning which would likely support snow across Swrn Nebraska
including areas along and south of I-80. A multimodel ensemble qpf
plume of all models near Imperial shows around 1/3 of an inch of
liquid. High snow liquid ratios are expected with this event which
could translate to 4 inches or more snow south of Interstate 80.

The blended forecast suggests around 3 inches of snow. If the models
continue this trend and tighten up across Swrn Neb then higher
snowfall would result. Note that the dynamics for this event are
still off the coast of British Columbia so a change in the axis of
heaviest snow...currently centered near I-70 in Kansas...could occur.

WPC has outlooked Swrn Neb with a 40-69 percent chance of 4 inches
of snow (moderate risk) and this appears to be consistent with the
12z ECM...the SREF and GFS Ensemble which were the farthest north
with the model track. The NAM and GFS show the best forcing between
Goodland and Dodge City and this could disrupt moisture transport
and limit QPF across Swrn Neb. The ECM frontogenesis is very
nebulous. The forecast is conservative and later forecasts can
increase snowfall amounts if warranted.

Very cold air will move in the wake of the disturbance Wednesday.
Cloudy skies Wednesday would limit warming for highs in the teens.
Lows Thursday morning are very problematic with clear skies
developing and snow cover in some areas. The forecast lows in the
single digits Thursday morning could be 10 degrees too warm in some
areas if significant snow falls Wednesday (2-4 inches).

The arctic high pressure will move off the high plains Friday with
highs returning to the 20s and 30s (just teens for highs Thursday).
Once again snow cover could have a significant impact on the
temperature forecast.

There is a chance of snow Saturday but this is based on the GFS and
its ensemble. The ECM is less amplified with a mid latitude wave
moving through the Nrn Plains. Temperatures are expected to moderate
Saturday and Sunday with highs mostly in the 30s. This is consistent
with h850mb temperatures warming back around 0C.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 541 PM CST Sun Dec 4 2016

Low level winds shear from 03z-08z at KLBF and from 09z-13z at
KVTN will be the main aviation concern the next 24 hours. There
will also be an increase in clouds this evening with VFR ceilings
near 10k feet agl after 08z.





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