Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 170916
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
316 AM CST Wed Jan 17 2018

.SHORT TERM...(Today and tonight)
Issued at 316 AM CST Wed Jan 17 2018

The RTMA temperature analysis indicates mild air is beginning to
spread across Swrn Alberta and Cntl MT. The RAP model shows this
warmer air spreading southeast through the Cntl high plains this
afternoon. The temperature forecast today uses a blend of the HRRR
and RAP models plus bias correction for highs in the 30s to lower
40s.

The best chance for 40s is across Nrn Neb and the Panhandle,
closest to the thermal ridge, and where mixing processes will be
maximized. H850mb temperatures rise into the low single digits
Celsius. Yesterday`s 00z upper air flight from KLBF indicated a
mixing height of just 1200 ft. KUNR in Wrn SD mixed to 1350 ft.

The temperature forecast tonight uses a blend of bias corrected
guidance for lows in the teens to around 20. This was a few degrees
warmer than the straight guidance blend, but perhaps not warm enough
given that warm air will continue to spread into Wrn and Ncntl Neb.
H850mb temperatures rise another 5C to around 7C.

Clear or nearly clear skies and light winds are indicated in the
models today and tonight. Full-sun will aid in mixing processes
today; the light winds will not. Light winds and clear skies tonight
should support the radiational cooling process.

.LONG TERM...(Thursday through Tuesday)
Issued at 316 AM CST Wed Jan 17 2018

Warm air advection from the west/southwest and the presence of upper
level ridging will continue to bring warm and dry conditions to the
forecast area through Friday.  The latest guidance indicates h85
temps in the low teens, which should translate to highs in the 50s
for most places both Thursday and Friday.

The ridge axis breaks down to the east on Friday with a deep
trough/low over the western coast.  This will allow for a period of
southwest flow atop the plains and the eventual passage of the
trough/low.  The models are suggesting the potential of a winter
system that would bring accumulating snowfall to much of the
forecast area as they prog ample QG ascent/frontal banding and
moisture. There continues to be some discrepancy with the timing of
the system.  The GFS remains on the quicker end of the envelope, but
has seemed to slow the arrival by 06-12 hours.  Thus, largely
removed pops from our forecast area on Saturday, except our far
northwest.  The later arrival though prompted us to keep pops across
our east well into Sunday night/early Monday morning.

While it/s too early to highlight areas of potential moderate or
heavy banded snow, the models are showing an area of negative
EPV/reduction across the primary frontal band over northwest Neb and
again as the next FGEN focuses over our far east.  Will need to
monitor for convective enhancement.

Otherwise next week we see a return to westerly or northwest flow,
which largely will have a Pacific origin.  Temperatures will be
close to average with occasional chances for light QPF.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1109 PM CST Tue Jan 16 2018

Quiet aviation conditions will continue over the next 24 hours.
Southwest winds will slowly shift to the west but will remain below
10 knots at both terminals. VFR ceilings with little to no clouds
through Wednesday evening.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...CDC
LONG TERM...Jacobs
AVIATION...Kulik



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