Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 231149 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
649 AM CDT Sat Sep 23 2017

Issued at 649 AM CDT Sat Sep 23 2017

12z aviation discussion updated below.


.SHORT TERM...(Today through Monday Afternoon)
Issued at 353 AM CDT Sat Sep 23 2017

The main change this period is to shift the highest precipitation
amounts slightly westward again, and limit it to generally less than
2.75 inches through Monday. The initial sfc low has moved into north
central MN early this morning, with the cold front just to the east
of the forecast area.

More moderate rain will slide in from the southwest from mid
afternoon on, ahead of the next sfc low and the next piece of energy
rotating in from the southwest in our quick southwest to northeast
flow at 500mb. A quick look at the 500mb pattern will show the
current low situated from NV through western MT with the trough wet
up across the western half of the nation, while a ridge dominates
the interior portions of the eastern U.S. Look for the 500mb low to
edge across UT Sunday, and become more of an open wave ejecting
northeastward across WY and eastern MT on Monday. Impresses with how
the thunderstorm potential has been a little more westward that
originally though. Will continue this trend through at least the
next day and a half, with a more westward push to thunderstorms.
Will be interesting to see what the 00Z sounding comes up for PW
values, as the daily record for 00Z/Sep 24th is 1.26in, with the
period of record dating back from November 1994. We should end up
closer to 1.5 to 1.8in if the NAM is correct. HWO wise, highlighted
the slight risk of excessive rainfall from WPC and the marginal risk
of severe thunderstorms, while trying to give a better idea of
precipitation amounts in general. The main pushes look to be mid
afternoon through tonight, before the focus really shifts to far
eastern SD and western MN.

.LONG TERM...(Monday Evening through Friday)
Issued at 353 AM CDT Sat Sep 23 2017

The models show an upper level low pressure area/trough to our west
on Monday night lifting northeast into southern Canada through
Tuesday night. This will bring the last of the chances of showers
east in the CWA for Monday night. Otherwise, the models all show
northwest flow aloft developing behind this trough and remaining
through the end of the week with upper level ridging to our west.
Therefore, after Monday night the rest of the period through Friday
looks to be dry with below normal temperatures. Highs will be mostly
in the 60s with lows mainly in the 40s from Monday night through


.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 649 AM CDT Sat Sep 23 2017

IFR/MVFR stratus ceilings are expected for all locations through
today and tonight as cool and moist low level winds remain. Along
with the clouds will be periods of showers along with some
thunderstorms. More widespread rainfall and lower vsbys are expected
for all locations later this afternoon and night as stronger lift
moves into the region. There will also be fog tonight lowering




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