Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 281155

Area Forecast Discussion
National Weather Service North Platte NE
655 AM CDT SUN AUG 28 2016

...Updated Aviation section...

.SHORT TERM...(Today and tonight)
Issued at 358 AM CDT Sun Aug 28 2016

The main concerns in the short term period center around
thunderstorm chances this afternoon and tonight with brief
locally heavy rainfall possible. However, no severe weather (in
regard to strong wind gusts and hail) is expected this afternoon-
tonight. Convection that develops is anticipated to be
unorganized to having little/weak organization. Mostly sunny skies
will transition to a mix of sun and clouds across portions of
southwest to north central NE by mid-late afternoon. Highs are
expected to be in the upper 80s to low 90s, about 5 to 10 degrees
above normal. Overnight, lows will be in the mid-upper 50s to mid-
upper 60s from western NE to far north central NE, that`s about 5
degrees to 10-14 degrees above normal, respectively.

A upper level trough in the upper Great Lakes at the start of the
period will continue to move east into western Quebec province by
early this evening while western and north central NE undergoes
weak 500 hPa height rises today as ridging occurs over the
Central Plains and the lower/middle Mississippi Valley. Flow
aloft is light at mid-levels with light westerlies expected at
500 hPa today. A weak low level jet is anticipated to develop
late this evening across western and north central NE that will
extend into eastern SD. Elsewhere, a weak lee surface trough is
expected to develop and sharpen that will extend south from the
western Dakotas across the NE Panhandle this afternoon. There
should be decent instability given the insolation and
destabilization that`s expected and moisture with surface dew
points in the mid 50s to lower 60s. In regard to thunderstorms,
weak vertical wind shear is expected so that should result in
mainly disorganized multicells with 0-6 km bulk shear that`s
generally around 10-15 kts. Shear then diminishes some further
after midnight. Coverage is expected to be isolated to scattered.
Moisture transport at lower-levels will be decent into central and
north central NE this afternoon and overnight. Precipitable water
values will generally be above 1.25 inches, approaching near
1.4-1.5 inches possibly late this afternoon/evening. Favorable
conditions are in place for local brief heavy rainfall to be
possible given the moisture available/transported, anticipated
weak storm motion around 5-10 kts, thermodynamic profiles, and
precipitable water forecasts near 150% of normal. However, general
flash flooding threat is expected to be low given the flash flood
guidance, coverage, and QPF that`s expected.

.LONG TERM...(Monday through Saturday)
Issued at 358 AM CDT Sun Aug 28 2016

Monday and Tuesday looking to be a little cooler than previously
thought, especially across southwest into central Nebraska.
Models are holding a broad ridge across most of the CONUS,
exception are a trough across the pacific NW and subtle waves
sliding across the US/Can border. Monsoon flow from the south
pacific and western Gulf are drawn north along the rockies then
drift to the northeast across western KS and central Nebraska
around the high pressure. Meanwhile at the surface southerly
winds continue to keep dew points above seasonal averages. Models
are favoring mostly cloudy skies with showers across eastern
Colorado/western Kansas into south central Nebraska. The
southeastern portion of the CWA will likely see the clouds and
could see showers and thunderstorms. With the expected increase
of cloud cover temps followed guidance trend of slightly cooler
than previous forecast. A few more breaks in the clouds expected
on Monday with highs in the mid to upper 80s (which may be
optimistic and could trend down further), then lower to mid 80s
for Tuesday. A mid level disturbance on Wednesday and another one
on Thursday brings additional chances for showers and
thunderstorms and highs around 80. Thursday night/early Friday a
warm front will push across the area with a brief warm up for
Friday and Saturday. Still seeing good low level moisture so
chances for thunderstorms, albeit low, continue along and post

Overnight with the rich boundary layer moisture lows will be
mild. Fog will be possible however will likely need some clearing
to drop temps and confidence is low about where/if there will be
much clearing. Thus will need to keep an eye on this daily and
add as needed.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 655 AM CDT Sun Aug 28 2016

Patchy fog has developed across portions of the forecast area this
morning reducing visibilities to MVFR category at some
sites, most notably, KLBF and KIML. Fog is not expected to greatly
impact to visibility restrictions this morning. It has been
included in the KLBF TAF with no mention present at KVTN. Fog
should dissipate between 7 and 9 AM CDT. In general, VFR
conditions are expected today. There is a slight chance to chance
for rain showers and thunderstorms this afternoon and tonight
across southeast NE to north central NE. Confidence is low in
terms of thunderstorm impacts to aviation terminals though given
uncertainty where they will develop. MVFR visibilities will be
possible though given the heavy rain potential. Rain shower and
thunderstorm chances then diminish early morning Monday.


.LBF Watches/Warnings/Advisories...


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