Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 221149
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
649 AM CDT MON AUG 22 2016

.SHORT TERM...(today through Wednesday)
Issued at 331 AM CDT MON AUG 22 2016

Quiet weather today, but strong and possibly severe storms are
possible Tuesday afternoon evening.

Latest satellite imagery has shown an accas cloud field developing
from near Fremont northeastward into northwest IA. Hires CAMs
suggest that a few sprinkles could develop there this morning, but
would be just northeast of our forecast area. Otherwise, the story
for today is increasing temperatures and breezy to windy
conditions developing, with speeds from 15 to 30 mph, and gusts 30
to 35 mph in northeast NE. Highs will be warmer than yesterday,
reaching the mid 80s to upper 80s mostly, but could reach around
90 along the NE/SD border region.

Southerly breezy winds continue overnight, but it should remain
dry, in advance of the trough currently moving through the
4-corners region. Low temps tonight should be back above normal
in the mid 60s.

Low level moisture will continue to deepen Tuesday on continued
southerly flow ahead of the upstream trough and cold front that
moves in Tuesday night. Tuesday morning should remain dry, but
storm chances increase by Tuesday afternoon when the cap
eventually breaks. By then, dewpoints will probably be in the
upper 60s to lower 70s, with available CAPE from 2000-3000 J/kg.
0-6km bulk shear values are 30-40 knots, thus sufficient
parameters are coming together for a slight risk of severe storms
across the area, which will continue into the evening hours. Wind
and hail will the be the primary threat initially, although there
are some indications that a warm frontal boundary could develop
that extends eastward from the surface low, which could set up
somewhere along or just north of I80. It could also just be an
outflow boundary reinforced by convection. Either way, if this
indeed develops, isolated tornadoes may occur in northeast NE and
northwest IA, although certainly too far out to pinpoint at this
time. Another threat with storms Tuesday will be potential heavy
rains just north of the boundary with training of storms possible.
For now have 1-2" rains north of I80, which may be conservative.
WPC has 2-2.5" rains in the same area, and has highlighted the
area in a slight risk for excessive heavy rainfall. Will continue
to monitor later model runs for placement of potential heavy rain
band.

Whatever MCS develops Tuesday evening should continue to push
eastward and will clear the area after midnight. Unsure if there
will be any additional development along the front as models
disagree, but will keep chance pops in just in case.

The frontal boundary continues to make slow progress through the
area on Wednesday. A secondary upper level impulse may allow
additional convection to develop along/south of the front through
the day Wednesday that would linger into Wednesday night. SPC has
the area along/south of I80 in a marginal risk for severe storms
that day.

.LONG TERM...(Thursday through Sunday)
Issued at 331 AM CDT MON AUG 22 2016

First couple of days of the extended period will be below normal
with daytime highs in the mid to upper 70s as we remain on the
north side of the cool front. Will maintain a slight chance of
thundershowers along the KS/NE border region Thursday into
Thursday night. GFS is drying during this time, but the ECMWF is
just a little further north with the moisture associated with a
southern stream trough. Precip chances do increase Saturday through
Sunday as the next upper trough begins to affect the region.

&&

.AVIATION...(12Z TAFS for KOFK...KLNK and KOMA.)
Issued at 635 AM CDT MON AUG 22 2016

VFR conditions through the TAF period. Forty to 50kt low level
wind shear early this morning and again this evening and tonight.
In between...included south to southwest winds at 12 to 20kts and
gusty.

&&

.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&

$$

SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...Zapotocny


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