Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 152339

Area Forecast Discussion
National Weather Service Omaha/Valley NE
639 PM CDT Sat Jun 15 2019

.SHORT TERM...(Tonight through Tuesday)
Issued at 338 PM CDT Sat Jun 15 2019

The potential for thunderstorms through the evening, then returning
chances for storms Sunday night through Tuesday, are the primary
forecast concerns.

Northwest mid level flow extended from British Columbia into the
Central Plains today. A mid level low was centered in Manitoba with
a potent shortwave rotating east across North Dakota, triggering
convection there. Farther south, a weak shortwave noted on water
vapor satellite loops and RAP analysis was drifting through eastern
Nebraska and western Iowa at early afternoon. Between these features
was an area of enhanced lift in southern Minnesota into northern
Iowa where severe thunderstorms had developed.

A weak cold front associated with shortwave was limping southeast
through eastern Nebraska and southwest Iowa this afternoon.
Lingering showers from overnight MCV were dotting the radar screen
across eastern Nebraska into west central Iowa. These showers and
associated cloud cover had kept temperatures and thus instability
low over most of our CWA, but sun had returned as of mid afternoon.
Parts of southeast Nebraska remained cloud-free for a longer
period today, and a few thunderstorms had popped there where
MUCAPE had topped 3000 J/kg as per RAP analysis. However any weak
convergence along front zone will be short-lived as front should
exit Nebraska well before 00Z. Therefore it appears there is only
a small window of opportunity both in space and time for storms
this evening, generally through about 00Z and in far southeast
Nebraska and southwest Iowa. If any storm maintain themselves,
large hail will be possible given instability and modest bulk
shear near 35kt.

Will end rain chances later this evening as surface high pressure
and northerly flow take hold. We should remain under that influence
through Sunday afternoon before high slides east allowing return
flow to set up.

Mid level flow from Sunday night through Tuesday will remain broadly
cyclonic across the region as Manitoba low moves across the northern
border, merging with persistent deep low just east of Hudson Bay.
Several shortwaves rippling through the Plains could trigger
convection at just about any time as they interact with increasing
moisture profiles.

Perhaps the best chance for stronger convection will come on Tuesday
as there is model consensus in showing stronger shortwave driving a
frontal boundary into our region.

.LONG TERM...(Tuesday night through Saturday)
Issued at 338 PM CDT Sat Jun 15 2019

A fairly active weather pattern will remain in place through the
week as cyclonic flow aloft remains over the region through mid
week, then a trend toward southwest flow takes hold by late week.

Longer range models are generally similar in showing broad cyclonic
flow across the Plains through Thursday morning, favoring at least
small rain chances and somewhat cooler temperatures. GFS and ECMWF
are both showing a more significant wave entering our region
Wednesday afternoon, but a drier atmosphere after Tuesday`s cold
front will likely limit convection.

Beyond Thursday morning, GFS and ECMWF diverge in handling main jet
pattern, with GFS maintaining broad cyclonic flow in the Plains
south of low extending along the Canadian border. The ECMWF keeps
more energy to the west in the Northern Rockies with southwest
mid level flow in the Plains, which would promote warmer
temperatures and aggressive northward moisture transport. In
either case, continuing chances for convection will remain in the
forecast, but potentially more potent storms are possible with
ECMWF solution.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 636 PM CDT Sat Jun 15 2019

VFR conditions through the period.




LONG TERM...Dergan
AVIATION...DeWald is the U.S. government's official web portal to all federal, state and local government web resources and services.