Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 250507

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1207 AM CDT Thu May 25 2017

.SHORT TERM...(Tonight through Saturday)
Issued at 250 PM CDT Wed May 24 2017

Temperatures are the main concern into Friday night, then will be
looking more at thunderstorm chances/rain amounts for Saturday.

System that helped bring showers to the area yesterday continue to
move away, while the next closed mid tropospheric low of concern
was dropping southeast from southern Alberta. 12 hour height falls
associated with that feature were quite impressive, up to 270
meters at 500 mb at 12Z this morning. Models are in good agreement
that the low will move to southern Saskatchewan by 12Z Thursday
and that mid level ridging will move into our area. Combination of
weak forcing and increasing moisture may be enough to trigger some
showers or isolated thunderstorms over parts of the forecast area
on Thursday. Forecast soundings suggest that atmosphere will be
capped during the day relative to any surface based convection,
but some fairly high based activity is possible. Chances should be
a bit higher Thursday night, as a weak cold front pushes through
the region.

A the surface, weak ridge axis over the area this afternoon will
slide off to the east/southeast tonight, with southeast winds
increasing a bit toward morning. Lows should range from the mid
40s to around 50, with highs Thursday reaching mainly 73 to 78.
Highs Friday are expected to be a couple of degrees warmer.

For Friday night and Saturday, it appears that a convective system
may develop out over the High Plains by Friday evening and then
move/spread east overnight toward eastern Nebraska. The 12Z runs
of the NAM and ECMWF are just slightly slower than the GFS, but
the GFS was given a little more weight than the others. Mid level
flow across the region will be mostly from the west or southwest
until Sunday, when the flow turns to northwest.

.LONG TERM...(Saturday night through Wednesday)
Issued at 250 PM CDT Wed May 24 2017

Pattern aloft in this period will be highly amplified to start
out, but should become more zonal mid to late week, based on the
GFS and Canadian models. The ECMWF has more ridging to our west
by late Thursday and a trough extending back southwest from the
Great Lakes region.

The weekend will be unsettled, but at least it appears that any
amounts would be pretty light. Chances seem highest Sunday
afternoon into the evening and then again that way for Monday.

Highs Sunday through Wednesday should be mainly upper 60s to mid
70s, and lows in the mid 40s to lower 50s.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1201 AM CDT Thu May 25 2017

VFR conditions tonight with increasing mid clouds fl100-150
through Thursday morning. Spotty elevated SHRA/TSRA possible
Thursday and can be added as needed when confidence is higher for
timing and coverage refined at all three sites. Added low level
wind shear in at KOFK for a couple of hours until the winds mix to
the surface. Light southeast winds...increasing to 10 to 20kts at
all three sites between 12-16Z and lasting through mid afternoon




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