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FXUS63 KOAX 230748
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
248 AM CDT Wed May 23 2018

.SHORT TERM...(Today through Friday)
Issued at 230 AM CDT Wed May 23 2018

The summer-like pattern over the next several days will mean
above normal temperatures, but also the risk for hard to pin down
storms.

The h5 low over the Nevada/Utah border will lift northward toward
Montana through Wednesday night. Stronger areas of convection are
north of the low level jet and extend from South Dakota into
southwest Minnesota and northern Iowa. A shortwave near the
Colorado/Kansas border will lift north this morning with isolated
thunderstorms over central Nebraska. Not sure if any of these will
make it into northeast Nebraska. There is an ill-defined boundary
near the NE/SD border and did keep the small pops in there.

Over the next few days, temperatures heat up into the upper 80s
and lower 90s and forecast soundings predict instability of
2500-3500J/kg with little or no CIN and very steep lapse rates.
The environment will be primed, it will just need something to get
storms going. As discussed, we don't have real strong signals
until Thursday night when there is lift with the shortwave trough
breaking down the ridge with a cold front. This afternoon, weak
lift does move into the region and the CAMS increase thunderstorm
chances in eastern Kansas. The NAM is dry locally, however
several of the other models indicate isolated storms possible this
afternoon in southeast Nebraska and southwest Iowa. Tonight some
of the storms over central Nebraska may make it into northeast
Nebraska. Thursday there is stronger warm air thus spotty storms
continue. Thursday night, the coverage increases with the
shortwave trough passage and some of the storms in Iowa could
linger Friday morning.

The precipitable water values are around and inch and these
increase to 1.5 inches by thursday morning and continue Friday.
These high pwats combined with storms motions of 10 to 20kts mean
that locally heavy rain will be possible. Related to severe
weather, the instability is moderate, however the shear is on the
weaker side. Locally heavy rain and marginal severe hail seem to
be the biggest risks.

Even though it will be warmer and more muggy, a south breeze each
day should help.


.LONG TERM...(Friday night through Tuesday)
Issued at 230 AM CDT Wed May 23 2018

The extended forecast Saturday through Monday still looks mainly
dry with above normal temperatures in the upper 80s to lower 90s.
A storm system will be over parts of California and Nevada and
affecting the Gulf and Atlantic coasts and we are in-between. That
being said, with moisture in place, heating and a weak cap or no
cap at times, it would not be unreasonable to see a few storms
over the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1133 PM CDT Tue May 22 2018

Current water vapor imagery depicts a subtle short-wave trough
moving through central NE with an associated increase in shower
and thunderstorm development noted immediately downstream from the
impulse over north-central NE. It appears that any subsequent
convective development will remain to the west of the TAF sites
overnight with a general increase in mid and high-level clouds. On
Wednesday, winds will become gusty from the south by late morning
in response to a deepening lee cyclone over the northern High
Plains. VFR conditions are expected to prevail through the
forecast period.


&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Mead
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