Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 161713

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1213 PM CDT Mon Apr 16 2018

.SHORT TERM...(Today through Wednesday)
Issued at 335 AM CDT Mon Apr 16 2018

Main forecast concerns are the potential for thunderstorms and
snow Tuesday night, snow lingering Wednesday and temperatures
through the period.

Closed low that brought snow to the area on the weekend was near
Chicago and moving slowly away from the area. A mid level ridge
stretched from Mexico up toward the western Dakotas while the next
system of concern was moving onto the west coast with height falls
of over 100 meters the past 12 hours. At the surface, a ridge of
high pressure extended from the Dakotas into OK. Low clouds have
been holding in longer than expected and could linger much of the
morning. This will have an impact on lows this morning.

Otherwise, we should see some sunshine later today. This will push
highs in the 40s at most locations. Areas with heavier snow cover
in northeast NE may only reach the upper 30s, but parts of
southeast NE could hit around 50. Surface ridge axis will build
east of the area tonight, with return flow developing. Southerly
winds and at least partial sunshine along with a warming boundary
layer should push highs upward on Tuesday, compared to today.
Expect a range from 45 to 50 near the SD border to lower 60s at
the KS border.

Diffluent flow develops Tuesday ahead of the next weather maker.
Overall, the 00Z GFS model seemed too fast with the system and did
not give it much weight. Preferred a blend of the NAM, ECMWF and
Canadian models. Models show steep mid level lapse rates and some
instability developing over the area Tuesday evening. There is
potential for some thunderstorms, and parameters suggests a few
may have small hail. A surface low should track from western KS
early Tuesday evening to southwest or south central IA by daybreak
Wednesday. As that happens, southerly winds will turn to the north
and bring in colder air. Model thermal fields still show some
spread, so determining snow accumulations is still problematic.
Hopefully model agreement will improve the next 24 hours. For now,
it appears that there is potential for generally 1 to 5 inches of
snow across northeast NE, with the highest amounts in our area
currently forecast along the SD border. Heavier snow seems to be
targeting northwest IA and southwest MN. The ECMWF QPF for both
Tuesday night and Wednesday seemed pretty reasonable. The big
issue though is the low level thermal fields. There does appear to
be at least a brief window where we could have some mixed sleet
or freezing rain before changeover to snow. Highs Wednesday
should be mostly in the 40s with some 50s possible toward the KS

.LONG TERM...(Wednesday night through Sunday)
Issued at 335 AM CDT Mon Apr 16 2018

We have been watching the longer term models which have been
showing a system moving in Thursday night and possibly lingering
into Saturday night. The mid level low with that system should
track east from CO and NM into KS and OK, then toward AR. Heaviest
precipitation should stay to our south, but light amounts of rain
and snow will be possible across eastern NE and western IA.
Preferred the 00Z ECMWF solution over the operational GFS at this
time. Drier weather is currently expected for Sunday with highs in
the 50s.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1208 PM CDT Mon Apr 16 2018

VFR conditions are expected throughout the entire TAF period at
all sites. Will be watching KOFK for potential fog development
overnight due to melting snow during the day, however probability
seems low at this time. Surface winds will become light and
variable overnight, then becoming easterly toward daybreak at all


Issued at 500 AM CDT Mon Apr 16 2018

Record lows for today, April 16

Location / value / year of record
Omaha    / 21    / 1875
Lincoln  / 21    / 1904
Norfolk  / 14    / 1904




LONG TERM...Miller
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