Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 111756
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
1256 PM CDT Wed Oct 11 2017

.SYNOPSIS...
Issued at 339 AM CDT Wed Oct 11 2017

At 08z...Surface low pressure across central and southeast
Montana extended southward along the lee of the Rockies. winds
remained light and variable across central into parts of southwest
Nebraska, while better mixing was occurring across the northern
panhandle into north central Nebraska. Skies were clear throughout
western Nebraska. Temperatures in and near the forecast area
ranged from 46 at Pine Ridge, to 29 at Broken Bow and Ord.

&&

.SHORT TERM...(Today and tonight)
Issued at 339 AM CDT Wed Oct 11 2017

Upper flow will become southwesterly today, as an upper trough digs
across the Pacific Northwest. Sunny skies this morning with
scattered cirrus moving across this afternoon. Temperatures at 850mb
will reach 15C in the far western counties, to around 10C in the
east. With a pressure gradient in place across Nebraska, south winds
will range from 15 to 25 mph, except lighter at 5 to 15 mph in
southwestern areas. This will aid in highs reaching near 70 from
Valentine through Imperial and areas west, to 64-67 in the
southeast.

For tonight, a surface trough will move east into the Dakotas and
the Nebraska panhandle. South winds will continue across the
forecast area. Winds will be light at 10 mph or less across the
south to 10 to 20 mph north central. Lows from 40 to 45 north
central with the coolest readings of 35 to 40 across the south.
Skies will remain mostly clear overnight. As the upper trough
advances across Idaho and Montana, a cold front will push east into
the western Dakotas and northeast Wyoming toward daybreak. This will
result in very warm 850mb temperatures as high as 19C to develop
across western Nebraska.

.LONG TERM...(Thursday through Tuesday)
Issued at 339 AM CDT Wed Oct 11 2017

An H5 trough digs southeast across the Rockies late week and
progresses east onto the Plains over the weekend. Once it reaches
the Great Lakes, flow aloft becomes quasi-zonal across the western
half of the CONUS. At the surface, a strong cold front drops through
the Plains Thursday with a secondary frontal passage late Friday.
High pressure then takes over early next week.

Thursday and Friday... Trended max temps toward the warmer guidance
Thu. to account for southerly flow early in the day and an H85
thermal axis bisecting the forecast area. The first fropa timing,
which the models are consistent with being generally 21z-00z, is
also conducive for sufficient daytime heating. Despite forcing and
lift with the front, moisture seems to be lacking, limiting precip
potential. However, kept chc PoP across the northwest Thu night. A
ribbon of mid level moisture begins to stream off the Black Hills as
low level flow turns easterly/upslope. Friday`s fropa will also
likely be dry with little to no moisture advection in the low levels
and abundant dry air H5-7. Highs Fri. will return to below normal
with H85 temps of 6-8C and mixed sun/clouds.

Saturday and Sunday... A stout shortwave pushes across the Plains in
conjunction with the upper trough. Moisture return off the Gulf is
better, and models indicate quite a bit of isentropic upglide.
Combined with H5-7 fgen and moisture reaching their peak late Sat,
adjusted PoP accordingly. ECM drops H85 temps to 0C invof Pine Ridge
overnight, so a brief period of RASN or SN is possible. Subsidence
quickly takes over Sunday, so cleared all precip out of the area by
12z. Winds may not be high enough Sat PM - Sun AM as GFS suggests 1+
mb/hr pressure rises behind the system, 35+ kts at H85, and a 1.5 PV
sfc drops to near 400mb.

Monday and Tuesday... Mainly fair conditions and warming temps as
low level flow alternates between southerly and downsloping. H85
temps approach 15C Tue with efficient mixing, resulting in highs in
the lower 70s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1254 PM CDT Wed Oct 11 2017

Quiet aviation concerns are expected at both KVTN and KLBF for the
next day. High pressure will result in dry and clear conditions
across the region. The only major concern will be tonight when low
level wind conditions are expected to develop at both terminals.
Otherwise, winds under 10 knots are expected through Thursday
morning.

&&

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

$$

SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Snively
AVIATION...Kulik



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