Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 260512

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1212 AM CDT Wed Oct 26 2016

.SHORT TERM...(tonight through Friday)
Issued at 238 PM CDT Tue Oct 25 2016

Lone shot at sensible weather in the next week is still likely for
at least some of the area tonight. Subjective 12Z upper-air analysis
indicates broad upper-level ridging over the central US, with
troughing west. A lead shortwave was analyzed over MT/WY, with a
deeper upper low off the Pacific Northwest coast.  A 115-kt upper-
level jet was coming ashore in north central CA.  An 850mb warm
front-like feature was noted across MT into SD, with a band of
showers developing from southwest to north central SD to west
central to southeast MN. Axis of 8C+ 850mb dewpoints extended
from TX/OK into KS/NE, with surface dewpoints rising into the 50s
to around 60 degrees this afternoon. 700-500mb temperature
differences of 20C+ were noted from the high Plains of SD/NE/KS
across NE/southern SD and into western IA. Surface low at 19Z was
noted in southwest CO, with secondary low in southwest SD, and
with a tight pressure gradient from central NE across IA aiding
southeasterly winds.

Main forecast concern is potential for showers and thunderstorms
this evening and tonight.  Believe rain will hold off in the CWA
until after 00Z, as convection-allowing models continue to slow
thunderstorm development and pull it further northward.  Convection
is expected to develop around 03Z, give or take a little, from
southeast SD into northeast NE.  Storms should then expand southward
ahead of the surface trough axis through the evening, with more
widespread coverage by around 06Z.  Around 750-1500 J/kg of elevated
CAPE is likely in that warm sector, aiding development of some late-
season thunderstorms.  CAPE profiles above the surface stable layer
are fairly skinny, and deep-layer/effective shear is progged to
weaken through the evening and overnight.  Initial storms may pose a
risk of being on the strong side, with small hail and perhaps an
isolated gusty wind.  As storms expand in coverage and make their
way eastward out of the area, rainfall of up to around a half inch
to inch is possible in some areas, mainly in the eastern CWA, given
unseasonably high PWAT around an inch.

Precipitation should exit the CWA by 12Z, with thunder decreasing
through the night. Once it passes, quiet weather is expected
through Friday, with continued above-normal temperatures. Under
fairly strong warm air advection on Thursday night and Friday,
have nudged mins up a touch on Thursday night. Also boosted winds
and max temperature on Friday. With temperatures approaching mid
to upper 50s for mins and 80 for maxes on Friday, temperatures
would be near but not quite reaching record warm readings.

.LONG TERM...(Friday night through Tuesday)
Issued at 238 PM CDT Tue Oct 25 2016

Dry weather and above-normal temperatures will continue through
Tuesday.  A cold front on Friday night will bring temperatures back
from near-record to merely above-normal on Saturday and Sunday.
Another round of warm air advection looks likely on Monday at least
in the southern CWA, while areas to the north may see a wind shift
that tempers heating. Either way, Halloween looks dry, with
temperatures well above normal.  The frontal passage should bring
temperatures on Tuesday back down to readings only somewhat above


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1206 AM CDT Wed Oct 26 2016

Showers and thunderstorms will generally be east of the the TAF
sites with VFR cigs early on. May be some patchy MVFR vsbys when
skies clear with fog then look for deteriorating conditions with
MVFR/IFR cigs Wednesday morning. Satellite pic show a large area
of low clouds and the RAP does bring this low level moisture
southward Wednesday morning. Included LLWS at KOMA early
on...then winds veer to southwest through northwest increasing to
10 to 15kts Wednesday.




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