Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 130946
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
346 AM CST Wed Dec 13 2017

.SYNOPSIS...
Issued at 343 AM CST Wed Dec 13 2017

A highly amplified pattern continues across the CONUS
and Canada tonight. Ridging was present from the west coast north
into eastern Alaska and the Yukon. Down stream of this feature,
shortwaves were noted over southern Saskatchewan and a second
disturbance was noted over far swrn portions of the Northwest
Territories of Canada. Further east, low pressure was noted north of
Hudson Bay with a deep trough of low pressure extending south into
Cuba. At the surface, low pressure was located over west central
Minnesota with a cold front extending to the west southwest across
South Dakota. A second, arctic cold front extended to the northwest
of the low into northeastern North Dakota and Manitoba. Across
western and north central Nebraska, northwesterly winds had increased
overnight in advance of the front with winds gusting to around 30
MPH at Valentine. Temperatures ranged from 26 at North Platte to 54
at Valentine.

&&

.SHORT TERM...(Today and tonight)
Issued at 343 AM CST Wed Dec 13 2017

Low pressure will quickly dive southeast today. The lead fold
front will track through the forecast area by midday with the
stronger arctic front backing into the northeastern forecast area
by 00z. Gusty winds today will facilitate good mixing today with
highs reaching the middle 40s in the north and middle 50s in the
south. Wind gust potential today is in the 30 to 40 MPH range per
BUFKIT forecast sounding data. The strongest gusts will be in the
northeast due to a combination of decent pressure rises, a tight
pressure gradient and stronger cold air advection. For tonight,
the shortwave, currently over southwestern portions of the
Northwest Territories, will dive south across the western Dakotas
and eastern Montana. This will approach the Black Hills toward 12z
Thursday. Impressive lift exists in advance of this feature and
extends se of the Black Hills, appg nwrn Nebraska toward 12z
Thursday. For now decided to hold off on the mention of snow
tonight, as it appears to hold off until after 12z Thursday
morning. This is in response to some dry air which will have to be
overcome first before snow can reach the surface. Will brief the
oncoming shift on this potential late tonight.

.LONG TERM...(Thursday through Tuesday)
Issued at 343 AM CST Wed Dec 13 2017

A couple of opportunities for precipitation during this forecast
period. The first will be Thursday as a weak disturbance drops south-
southeast across the central and northern plains. Amounts look light
at this time with a mix of light rain and snow across mainly
northern Nebraska. Perhaps a better chance of precipitation will
come Saturday. However, the GFS and ECMWF are not in agreement with
the track of the system. The GFS drops the system south through the
Rockies, while the ECMWF brings the system southeast across the
central plains. The ECMWF has shown good run to run consistency, and
has a band of strong mid level frontogenesis moving northwest to
southeast across the area behind a strong cold front. Will limit
pops to less than 50 percent at this time due to model differences.
If the ECMWF verifies, some locations could receive a wetting 1/10
of an inch or so of liquid precipitation from a mix of rain and
snow.

Otherwise gusty winds expected with the Thursday system, with
northwest wind gusts to 45 mph possible across western and southwest
Nebraska and 35 mph elsewhere. Otherwise continued mild with no
arctic air anticipated.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1113 PM CST Tue Dec 12 2017

A cold front will move across western Nebraska between 06z and
12z, with northwest winds increasing to 32015g25kt behind the
front, Winds will peak near 33023g32kt between 12z and 20z, then
gradually diminish toward the end of the Taf period. An increase
to scattered to broken high cloudiness overnight and Wednesday.


&&

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

$$

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Taylor
AVIATION...Roberg



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