533
FXUS63 KLBF 210512
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
1212 AM CDT Sat Oct 21 2017

.SHORT TERM...(This evening through Saturday)
Issued at 328 PM CDT Fri Oct 20 2017

The main weather story over the next day or so is the upper ridge
exiting the Plains and the associated surface cold front sweeping
across the region.

This evening and tonight... Maintained chc PoP with the fropa after
06z across the Sandhills with schc SW Neb. Forcing, lift, and fgen
are rather strong given the stout mid level shortwave combined with
the front. However, the overall moisture profile is lacking with
bouts of dry air either in the low or mid levels. Forecast soundings
suggest marginal instability to support a rumble of thunder, but it
doesn`t coincide with the best moisture. Kept min temps above
guidance to account for increased cloud cover and elevated winds.
Trended winds up with the fropa for pressure rises of 2mb/hr, H85
winds near 40kts, and 1.5 PVU dropping to 550mb.

Saturday... Kicked out all PoP by 18z as strong subsidence/
isentropic downglide takes over. General agreement among the model
suite with CAA of 10C at H85 from 00z Sat to 00z Sun. Max temps
split MAV/MET, but temps could be underdone depending on sky cover,
downsloping winds, and a hint of a weak thermal ridge riding off the
Rockies late in the day. Elevated fire weather conditions continue
in the panhandle where RH`s approach 20% with gusty northwest
winds.

.LONG TERM...(Saturday night through Friday)
Issued at 328 PM CDT Fri Oct 20 2017

Strong radiational cooling will offset the warming effects of
westerly downsloping winds early on Sunday.  Based off the latest
available guidance, lows in the upper 20s to lower 30s appear
likely.  River valleys and northwest Nebraska will be the coolest
sites just after daybreak, especially if we decouple early.
Increasing subsidence with a transitory mid level ridge will
suppress cloud development on Sunday.  With full sunshine in place
and forecast westerly downsloping winds, highs will rebound back
into the 70s for most locations.  The downsloping winds will dry the
lower troposphere with relative humidity during the peak heating
hours in the 20s across the forecast area.  20-ft winds are
generally forecast at 15 mph or less, so the threat of large fire
growth is minimal at this point. It should be noted however that
winds are forecast to increase slightly late afternoon over far
western portions of zone 204 Sunday afternoon, near critical fire
weather conditions are possible there and will be watched closely.

A cold front will cool temperatures slightly early next week, but
bring in some breezy conditions.  Wind gusts in excess of 25 mph are
possible Monday afternoon, but the cooler temperatures will allow
for higher minimum relative humidity.  The roller coaster of
temperatures continues mid week as another transitory ridge builds
northeast across the central plains.  After cooler temperatures
Tuesday, highs return back into the 70s Wednesday.  The warm
downsloping winds will dry the lower troposphere again to near
critical thresholds with some wind forecast Wednesday afternoon.  A
strong cold front arrives late Wednesday night.  Strong winds from
the northwest will accompany the frontal passage with cooler
temperatures for Thursday.

Precipitation chances round out the work week as an upper trough
crosses the plains, but model consistency is not the best, so those
chances are marginal/conditional at this point.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1211 AM CDT Sat Oct 21 2017

Main aviation concern will be strong winds ahead and with the
frontal passage through the early morning hours on Saturday.
Frequent gusts above 25kts tonight across western Nebraska.
Frontal boundary lies across the panhandle from KRAP to KBFF to
K82V. Front will continue to push east into western Nebraska
through the early morning hours. Some associated light showers
associated with the front over northwest Nebraska. Showers
expected to be fairly light. Some low level wind shear expected
across western Nebraska with low level jet at 850mb producing some
southerly winds to 40-45kts. Breezy northwest winds will continue
behind the front on Tuesday with clearing skies.

&&

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

$$

SHORT TERM...Snively
LONG TERM...Jacobs
AVIATION...Power