Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 181715 AAB

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1215 PM CDT Sun Mar 18 2018

Issued at 950 AM CDT Sun Mar 18 2018

Made a few modifications to the forecast this morning. Added some
PoPs to the far west for ongoing light pcpn. Also expanded fog a
bit and extended it some out west where a few reports of dense fog
have been received via mping. Adjusted temps a bit too given all
the expected cloud cover today.

UPDATE Issued at 652 AM CDT Sun Mar 18 2018

12z aviation discussion updated below.


.SHORT TERM...(Today through Monday Afternoon)
Issued at 408 AM CDT Sun Mar 18 2018

A good portion of the region is situated under stratus deck. The
clouds are keeping temperatures from falling with many locations in
the lower 30s. Western and portion of south central SD have cleared
this morning which has led to patchy to areas of fog. The lowest
visibility is confined to western SD at this time. Will maintain
patchy fog in the forecast through the mid morning hours. Despite
the cloudy skies yesterday, high temperatures did manage to exceed
expectation. Today seems to be no exception.

Later this afternoon, an area of low pressure will strengthen over
eastern Colorado. This system, along with upper level support aloft
should spread pcpn into far western SD. Most CAMS keep this CWA dry
until at least 0Z Monday. By 6Z Monday, pcpn may reach the James
River Valley, but more likely closer to 12Z Monday. Precipitation
chances will continue on Monday. With rather warm surface temps,
along with overall weak lift, snowfall amounts should range
between one to three inches.

.LONG TERM...(Monday Evening through Saturday)
Issued at 408 AM CDT Sun Mar 18 2018

The models were consistent and continue to agree well on likely
light snow mainly for the east for Monday night into Tuesday morning
with a short wave trough sliding east. Some more chances of
rain/snow remain into Tuesday afternoon and evening with more short
wave troughing dropping in from the northwest. Otherwise, Wednesday
into Thursday morning is the only time in the long term that is dry
for now as upper level ridging builds over the region. The models
then continue to show a large upper level low pressure trough moving
into the western U.S. Short waves coming off of this trough and
across our region bring back rain and snow chances to the area
mainly for Thursday afternoon into Friday. The main issue will be
the weekend as the main energy out west moves into the central U.S.
and intensifies. All three models (EC, GFS, Canadian) show something
different as this system moves into the central U.S. The EC was the
model that showed a stronger system with a more prolonged rain/snow
event from Saturday through Sunday. At this time, the consensus was
for good chances of precipitation through this period. High
temperatures will continue to be near to almost 10 degrees below
normal through the entire long term. Mainly mid 30s to lower 40s are
expected on Tuesday and Wednesday with upper 30s to the lower 50s
from Thursday through Saturday. Sunday is expected to be cooler and
mainly in the 30s to lower 40s.


.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1213 PM CDT Sun Mar 18 2018

Mostly IFR cigs are expected through the period, with some IFR
vsbys possible with fog and snow later tonight, and on Monday.
KPIR/KMBG will see the pcpn first, with KABR/KATY not getting much
snow until Monday.




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