Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 290502

Area Forecast Discussion
National Weather Service North Platte NE
1202 AM CDT FRI JUL 29 2016

...Updated Aviation section...

.SHORT TERM...(This evening through Friday)
Issued at 205 PM CDT Thu Jul 28 2016

At 20z a large complex of elevated showers and storms was pushing
southeast through southwest and into south central Nebraska, along
and north of a tight mid-level thermal axis extending from the
Panhandle into northeast Colorado and northwest Kansas. As a result
of the multiple rounds of convection so far today the corridor of
strongest instability has been pushed just south and west of the
forecast area, which lowers confidence in the severe potential for
the remainder of the day. Additional shower and thunderstorm
activity has been noted across north central Nebraska and
northwestward into western South Dakota, just ahead of a mid-level
shortwave trough diving southeast out of Montana. Visible satellite
also shows clearing skies across much of western Nebraska in the
wake of the thunderstorm activity. A few hours of sunshine through
peak heating may be enough to build up enough instability to sustain
and possibly generate more convection, which is supported by some of
the latest hi-res model runs. This will keep chance POPs in the
forecast across much of the CWA through remainder of the afternoon
and into the evening hours. Strong deep layer shear will promote the
potential for a few strong to severe storms, however meager
instability will likely limit the overall threat.

Areas of fog are possible late tonight and continue into early
tomorrow morning on the higher terrain of western Nebraska and
eastward into the Platte River Valley in Lincoln County. Forecast
soundings show the fog dissipating between 12-15z. Northwest flow
aloft and an active weather period continues tomorrow. The
convective setup is a bit ambiguous as it is tough to identify any
baroclinic zones to serve as foci for convective initiation.
However, SBCAPE between 500-1000 J/kg should be sufficient to fire
off at least isolated convection, especially if any remnant outflow
boundaries from today`s activity remain in the area. Left the CWA in
slight chance POPs through the afternoon period due to the high
amount of forecast uncertainty.

.LONG TERM...(Friday night through Thursday)
Issued at 205 PM CDT Thu Jul 28 2016

Long term trends are consistent again today. Will use a blend of
NAM and GFS for mid term and ECMWF and GFS for long term
solutions. Friday night as upper wave moves across northern plains
isolated to scattered thunderstorms to develop in the Nebraska
panhandle and then spread east over night in fast northwest flow.
This area of convection will be aided by upslope flow and a weak
low level jet. Ongoing precipitation Saturday morning over north
central zones as upper wave moves east. Temperatures rebound into
the low to mid 80s as upper closed low over southwest Canada helps
to sharpen ridge into the northern plains. Highs in the upper 80s
to low 90s on Sunday as a warm front moves across western
Nebraska. Warm front will be a focus for thunderstorm development
Sunday night and then front that is being pushed through by upper
closed low over south central Canada on Monday. Cooler Canadian
air will follow in the wake of the aforementioned upper low on
Tuesday night Wednesday. Highs falling back into the 80s.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1200 AM CDT Thu Jul 28 2016

Isolated-scattered weak unorganized convection is currently
present across portions of north central and central NE. Current
thinking: Thunderstorms and rain showers will continue to push
southeast though these areas. exiting central NE in the next two
to three hours. May see a few isolated thunderstorms & showers
develop across central NE/western NE, however, confidence is low.

New concern will be patchy/areas of fog developing early this
morning, especially in climo prone areas. Fog development is
anticipated to occur after 8 UTC with dissipation occurring
between 12-14 UTC. Scant areas of low stratus/fog already evident
from Fog Sat product. As such, mentioned MVFR vis in TAFs at
this time but will need to monitor as the night progresses to stay
on top of trends. Still slight chances for showers and
thunderstorms across much of the forecast area, however,
confidence remains low to place anything in the TAFs.


.LBF Watches/Warnings/Advisories...


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