436
FXUS63 KOAX 290435
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1135 PM CDT Sun May 28 2017

.SHORT TERM...(Tonight through Wednesday)
Issued at 310 PM CDT Sun May 28 2017

Closed upper low over southwest Ontario this afternoon will be
the primary weather feature for the area in the short term.

Most of the Northern Plains region and lower Missouri Valley will
remain under cyclonic flow associated with the Ontario low for
much of the forecast period before backing flow develops on
Wednesday as upper ridge over the northern Rockies shifts slowly
east.

A cold front over the Northern Plains at 19Z will move into the area
later tonight. The cold front along with an upper short wave
trough dropping across the upper Midwest may trigger some spotty
showers over the area tonight. Moisture will be limited however
so little if any measureable rainfall is expected with sprinkles
most likely. Slight cooling Monday into Tuesday behind the front
with more extensive clouds and showers expected north and east of
the area. High pressure then builds from the Northern Plains into
the lower Missouri Valley Tuesday night and Wednesday with return
flow moving into the area by Wednesday afternoon as the high
shifts east.

.LONG TERM...(Wednesday night through Sunday)
Issued at 310 PM CDT Sun May 28 2017

Thunderstorm chances return to the region Wednesday night into
Thursday morning as southerly flow increases ahead of a lee side
trough over the western high plains and frontal boundary develops
across the area Thursday into Friday. Weekend period becomes more
uncertain as models differ on solution with ECMWF building ridge
into the region while GFS and GEM keep more troughing in the area.
Current forecast will keep some chance PoPs for Saturday before
drying out on Sunday but limited confidence at this point.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1135 PM CDT Sun May 28 2017

Mosaic radar data as of 04z indicate isolated showers stretching
from southeast SD and northwest IA through northeast into south-
central NE. This activity is moving southeast ahead of a shortwave
trough progressing through the mid MO Valley. Given the sparse
nature of the convection, no mention of SHRA is currently planned
in the 06z TAFs. Will continue to monitor up to issuance time
though. Otherwise, expect passing mid-level clouds overnight with
boundary-layer-based cumulus (FL060-070) once again developing
Monday afternoon as low-level lapse rates steepen. This process
will also yield gusty northwest winds by late morning/early
afternoon which will diminish by evening.

&&

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

$$

SHORT TERM...Fobert
LONG TERM...Fobert
AVIATION...Mead