Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 151141
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
641 AM CDT Sun Apr 15 2018

.SHORT TERM...(Today through Tuesday)
Issued at 330 AM CDT Sun Apr 15 2018

The main forecast concerns in the short term are snow chances
lingering today along with some areas of blowing snow. Then we
will focus on temperatures tonight into Tuesday.

The storm system that brought a variety of precipitation and
blizzard conditions to at least parts of the area yesterday was
quite challenging. Not only with precipitation types, but with
accumulations. This was due to uncertainties with the lower and
mid level thermal fields and ground temperatures that were
relatively warm to start with.

Water vapor satellite imagery early this morning showed a closed
mid level low over southwest IA, just east of our forecast area.
Abundant lower and mid tropospheric moisture was being pulled
north ahead of the low but like yesterday, there was not a well
organized deformation zone to the north and northwest of the low.
Some light snow showers continued to move south across parts of
the forecast area behind the low. Some of the short range high
resolution model solutions show some minor snow accumulations in
mainly western IA this morning. Have increased POPs there through
noon then we will should only see flurries at most. Farther east,
the snow will continue in central and eastern IA. Gusty north or
northwest winds linger today with some blowing snow. Look for
highs mainly in the lower and mid 30s with clouds persisting.
Winds should gradually diminish tonight with decreasing cloudiness
as high pressure at the surface builds toward the forecast area.
Went a little below MOS guidance for lows tonight.

On Monday, expect partly to mostly sunny skies with generally
poor mixing. So highs will be in the 40s north and upper 40s or
lower 50s south. Dry weather should continue Monday night into
Tuesday. Southeast winds are expected to bring in some warmer air
for Tuesday.

.LONG TERM...(Tuesday night through Saturday)
Issued at 330 AM CDT Sun Apr 15 2018

Things turn active again by Tuesday night into Wednesday. The
atmosphere starts to destabilize by late Tuesday afternoon ahead
of the next shortwave trough. The 00Z GFS model seemed a bit too
fast with development of precipitation compared to the ECMWF, NAM
and Canadian model. Will mention potential for thunderstorms at
least in the evening, then as colder air moves into northeast NE
that will change the rain over to snow. Some accumulations of 1
to 3 inches are possible Tuesday night into Wednesday, especially
near the SD border. We will be monitoring this closely because QPF
amounts are fairly high, and determining when the precipitation
type changes will be critical for snow accumulations. That system
should push out of our area by Wednesday night with dry weather
into Thursday.

By late Thursday, we should be under the influence of a mid level
ridge, but another potent system will be organizing to the west
toward the Four Corners region Thursday night. Right now, it looks
like the main low will move across OK and KS. There are model
differences in timing and location, so at this point it is
probably just best to say it is too early for details but that we
are monitoring. At this time, it looks like NE and IA would be on
the northern edge of the precipitation area, which could be rain
and snow.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 635 AM CDT Sun Apr 15 2018

Area remains under strong cyclonic circulation on the backside of
departing upper low over eastern IA this morning. MFVR vsbys at
KOMA will improve after 15Z as band of snow shifts east. MVFR cigs
however will likely prevail through 00Z before VFR cigs develop
00Z to 06Z. Gusty north winds also expected to continue through
00Z with gusts to near 30kts at times.

&&

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

$$

SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Fobert



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