Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 170920

Area Forecast Discussion
National Weather Service Aberdeen SD
420 AM CDT Mon Oct 17 2016

.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 419 AM CDT MON OCT 17 2016

Area of dense fog continues to push eastward and is eroding as it
does so. Had earlier this morning issued a dense fog advisory for
the James Valley and areas just to the east, but let it expire at
09Z as conditions clear out.

Main story for today will be the low pressure system moving eastward
across southern SD. Already seeing some light rain showers moving
northeast across western SD, although some of this likely having
trouble reaching the ground at this point. Will continue to see
profiles moisten through the morning. Models continue to peg north
central SD into the northern James Valley for best rainfall chances
today into this evening. Have increased POPs to likely for this
area. Things get a bit interesting this afternoon and will have to
watch where the warm front sets up. RAP/HRRR solutions take a
slightly more northward track compared to the GFS/EC in regards to
the low pressure/warm front placement. A few CAM solutions actually
bring some thunderstorms to the southeast CWA later this afternoon
so have inserted thunder back into the forecast. If the GFS/EC
tracks verify though, then thunder will likely be held back to the
south into southeast SD and southern MN. Wind speeds were increased
today into this evening as well as models continue to trend higher
with wind speeds on the back side of the low. This change was more
noticeable for south central SD and the southwest CWA where winds
are expected to be breezy/windy this afternoon on the back side of
the low pressure.

On Tuesday, a large surface high moves into the central Plains. This
will bring tranquil conditions to the area with a westerly breeze
and seasonal temperatures. For Wednesday, will be watching shortwave
energy tracking southeast across the region. EC a bit more robust
with the energy and is actually generating some precipitation, while
the GFS/NAM remain dry. Inherited SuperBlend POPs continue to stay
dry, but would not be surprised if POPs need to be added soon if the
EC remains consistent and the 12Z runs of the GFS and NAM start to
latch onto the EC.

.LONG TERM...(Wednesday Evening through Sunday)
Issued at 419 AM CDT MON OCT 17 2016

An amplifying mid level pattern is well under way at the beginning
of the period, a positive phase of the PNA pattern the end result.
Digging s/w energy early in the period should pass mainly south of
the region, so will maintain mostly dry forecast. After that, a mid
level ridge builds across the Northern Plains. Under this ridge it
should remain mostly dry despite a few glancing blows of s/w energy.
Moisture availability just looks too scant. Meanwhile, temperatures
should favor above normal for the vast majority of the forecast


.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1221 AM CDT MON OCT 17 2016

For the most part, VFR conditions should prevail across the KPIR
and KMBG terminals through late afternoon Monday. Short range
model guidance suggests rain chances will be on the increase
during the day on Monday at the KMBG terminal.

MVFR cigs have cleared the KABR terminal. With several hours of
clear skies and light winds expected for the rest of the night
amid rather high amounts of surface/boundary layer moisture that
no longer looks to get scoured out, there will probably be one or
more periods of reduced visibility in ground fog.

The same can be said at KATY, except still waiting for the mainly
MVFR low clouds to clear off there before the fog can have a
chance to form. Later in the day on Monday, perhaps lasting into
the early evening hours, there could be some isolated to widely
scattered shower/thunderstorm activity developing or passing over
the KABR and KATY terminals as well.




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