Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 221206
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
706 AM CDT Sat Jul 22 2017

.SHORT TERM...(Today and tonight)
Issued at 354 AM CDT Sat Jul 22 2017

An MCV is slowly moving east across northeast Colorado early this
morning. This is forecast to continue slowly east today and cross
southwest Nebraska. At least scattered showers and thunderstorms are
possible with the passage of the MCV. In addition quite a bit in the
way of mid and high level cloudiness will be associated with the
disturbance, and this could hold highs down a few degrees especially
across central and southwest Nebraska. However, considering
temperatures are in the low 80s at this time (4am CDT) and warm air
aloft (H850MB temps in the lower to mid 20s Celsius) any breaks in
the clouds will allow for a rapid warm up. So will maintain close to
guidance, with highs in the lower 90s at most locations. Across
northern Nebraska where more sun is expected, mid 90s looks good. As
far as any severe storms, not likely, as instability is weak due to
increased mid level clouds. The only exception could be across
extreme southwest Nebraska, where a bit more sun will allow for some
destabilization. Even here though the severe risk is marginal at
best.

As skies clear tonight, winds decouple, and drier air filters south,
a rather cool night compared to the last several is expected. Most
guidance has lows ranging from the mid 50s to lower 60s, and see no
reason not to follow those numbers.

.LONG TERM...(Sunday through Friday)
Issued at 354 AM CDT Sat Jul 22 2017

A building ridge aloft over the Four Corners expands onto the Plains
by midweek, helping temperatures remain summerlike, then retreats
west late week. Toward the surface, a slow moving front across the
northern Plains will bring periodic precipitation chances to western
Nebraska.

Sunday through Tuesday... Predominantly southerly flow at H85 sets
up a WAA scheme, culminating with a thermal ridge axis bisecting the
forecast area Tuesday. With temps approaching 30C, highs will reach
the mid 90s for much of the area, especially with a well mixed
boundary layer to 650mb. Kept a schc TSRA Mon PM as a trough is
situated off the higher terrain in the panhandle and decent moisture
advection over central Neb is shown by dew points rising into the
60s again. GFS soundings suggest abundant CAPE, but deep layer shear
remains rather limited. With storm motion under 10 kts and very warm
cloud layer, heavy rain and marginally severe hail will be the
primary concerns. For Tuesday, the boundary inches closer to the
Sandhills, but the best forcing and moisture remains across northern
Neb, especially when the nose of the LLJ lands near the SD/NE
border. CAPE takes on more of a skinny profile, and as shear remains
weak with quasi steep lapse rates, the severe potential appears meek.

Wednesday and beyond... The cold front drops south as a new sfc low
develops in northeast CO Wednesday. This will likely be the best
shot at widespread precip this week. Surface/H85 easterlies will
also help draw in moisture and add to the upslope forcing. A sfc
high quickly settles in from the Dakotas on Thursday, shutting off
the moisture flow temporarily. Upslope flow returns Friday and
Saturday, so will have to monitor downstream development off the
divides and Black Hills. Temperature wise, confidence is low in
Wednesday`s highs due to fropa timing and precip expanse early in
the day. Potential for mid 90s again if the front slows, but
increased precip coverage or earlier onset of convection may hold
highs in the 80s. Made little change to previous forecast. Did curb
max temps a degree or two Thu and Fri toward the middle of
guidance.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 626 AM CDT Sat Jul 22 2017

Scattered showers and thunderstorms are expected across southwest
Nebraska much of the day. These could impact the KLBF terminal,
but due to the scattered nature will only carry a vicinity showers
mention in the TAF. Otherwise VFR expected all areas with winds
light at 10 kts or less.

&&

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

$$

SHORT TERM...Taylor
LONG TERM...Snively
AVIATION...Taylor



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