Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 210524

Area Forecast Discussion
National Weather Service North Platte NE
1124 PM CST Fri Jan 20 2017

.SHORT TERM...(This evening through Saturday)
Issued at 348 PM CST Fri Jan 20 2017

Remnants of the first in a series of Pacific storm systems is
located across eastern Colorado this afternoon. This system will
track northeast across the area tonight. A weak area of
deformation on back side of the system will cross western and
central Nebraska this evening, with models indicating an
increasing area of light rain or wet snow within this region. Have
increased pops to 50 percent to account for this. Not expecting
much in the way of liquid accumulation, possibly a few hundreths,
and not forecasting any snow accumulation. Otherwise may see some
patchy fog across portions of central into north central Nebraska,
but mid level clouds will likely limit widespread fog development.

Saturday will be quiet. Surface low pressure will deepen across
eastern Colorado through the morning. This low will eventually
develop eastward through the southern plains later Saturday, and
will not impact our area. A mild day is in store for us, with
highs climbing well into the 40s if not a few lower 50s across
southwest into central Nebraska. Sided with the warmer side of
guidance due to guidance not being warm enough lately.

.LONG TERM...(Saturday night through Friday)
Issued at 348 PM CST Fri Jan 20 2017

The main sensible weather concern in the long term period is the
potential for a winter storm late Monday Night to early Wednesday.
In that time period the main challenges were precipitation
changeover timing, location of heaviest snowfall, snow amounts,
and winds. Additional concerns beyond that time frame, Wednesday
through Friday, for sensible weather impacts were low. Likewise,
generally quiet conditions are expected in advance of this system
late this weekend through Monday afternoon.

Tomorrow night, broad cyclonic flow remains in place at 500 hPa
across much of the CONUS at the start of the period with a series
of multiple short wave troughs embedded in the mid-level flow.
Wherein disturbances are located in the Upper Mississippi Valley,
eastern NM and Texas Panhandle, and another in southern Manitoba
at the start of the time period. The southernmost disturbance
will develop into a closed low early on tomorrow night and then
move eastward over the next 24 hours lying north of the central
Gulf Coast. Meanwhile, ridging will occur aloft over the southwest
CONUS and will extend into the Central Rockies. A surface low
pressure system will be moving south of the area in the Southern
Plains Tomorrow night and then tracks into the Tennessee Valley
Sunday. Surface high pressure builds into the local forecast area
on Sunday. The ridge aloft will then shift eastward and extend
from the Southern Plains into the Middle Mississippi Valley by
Monday, in the meantime the next wave will be progressing through
the western CONUS.

Thereafter, deterministic guidance continues to show the
potential for a winter storm system impacting the region. However,
guidance continues to show differences in storm track and
location/phase with this system though timing with the system
remains fairly steady. While there are apparent differences in
guidance and subsequently the envelope of solutions (with the GFS
forecast cycles steadily moving incrementally farther north in
successive runs and the ECMWF generally displaced south of the GFS
solutions), there is increased confidence in the system impacting
western and north central NEB.

A closed low is expected to develop and move onto the Central High
Plains midday Tuesday and then move into the southern Upper
Mississippi Valley area-Iowa area by late Tuesday. Thereafter the
mid-level low is expected to track into the Upper Great Lakes by
midday Wednesday. Meanwhile, a surface low is expected to develop
in the southern portion of the Central Plains early Tuesday
morning. The surface low will then lift into the Middle
Mississippi Valley by late Tuesday. Current thinking is the best
potential for heaviest snow (exceeding 3 inches) lies across the
northern half of the Sandhills into North Central NEB towards the
SD border over Tuesday into Tuesday Night. Wherein across US
Highway 20 and the northern half of 83 could be impacted by
moderate to heavy snow. Furthermore, winds will be gusty on the
backside of the surface low pressure system Tuesday as it departs
away from western NEB. Winds then continue Tuesday night. Gusty
northwest winds up to 35 mph will promote blowing and drifting
snow, and thus reduced visibilities. Snow chances then linger
early Wednesday into Wednesday morning.

Wednesday and beyond, dry and quiet weather is anticipated. A
large amplified ridge builds and moves onto the west coast
Wednesday while a trough extends into the southwest CONUS east of
the ridge. While there are apparent differences in guidance, the
area of high pressure looks to build and be influencing much of
the western CONUS by Friday.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1122 PM CST Fri Jan 20 2017

A weak disturbance will exit western Nebraska overnight. At KLBF and
KVTN, VFR conditions should persist with light westerly winds
below 10 kts.




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