Area Forecast Discussion
Issued by NWS Aberdeen, SD

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KABR 200532 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1232 AM CDT Fri Apr 20 2018

Issued at 914 PM CDT Thu Apr 19 2018

No changes planned to the forecast tonight. But, local streams,
creeks and rivers are being monitored closely. With the warm up
comes a faster rate of snow/ice melt within area drainage basins.
Between recent reservoir water releases and considerable
snowmelt, several rivers and creeks within the James River valley
and the Big Sioux River valley (up in the Glacial Lakes region on
the Prairie Coteau) have responded and are either running at
bankfull or rapidly approaching bankfull. South Branch Mud Creek
near Rauville has gone above flood stage this evening. An Areal
Flood Advisory was issued a short time ago for that area, after
coordination with the Codington County Sherrif`s Office.
Additional Flood-related products may be needed within the next 24
hours for some locations throughout northeast South Dakota (and
possibly west central Minnesota). Flooding situations can be
particularly dangerous at night. Don`t drive through areas where
water covers the road!

UPDATE Issued at 640 PM CDT Thu Apr 19 2018

See below for an aviation forecast discussion for the 00Z TAFs.


.SHORT TERM...(This Evening through Friday Afternoon)
Issued at 300 PM CDT Thu Apr 19 2018

Though largely passing south, a large cut-off low currently
across the 4-corners region of the US will migrate east towards the
Plains and impact our weather during the short term. Cloud cover
will be on the increase this evening into Friday which, along with
southerly surface winds, should prevent temperatures from dropping
too far below the low 30s/upper 20s tonight. Conversely,
increasing and eventually widespread cloud cover Friday may limit
daytime high potential to the upper 40s and mid to lower 50s.
Models do bring light showers into southern South Dakota by the
noon hour Friday, however temperatures should be warm enough for
an all rain event. POPs continue through the day Friday mainly
across central South Dakota, but totals only on the order of
hundredths of an inch of moisture are expected.

.LONG TERM...(Friday Evening through Thursday)
Issued at 300 PM CDT Thu Apr 19 2018

The extended period begins with high pressure exiting to the east
and low pressure over the lee of the Rockies. The southern portion
of this low will slide southeastward to Texas by midday Saturday,
dragging an area of precipitation with it. The northern fringe of
this precipitation looks to possible affect western and southern
portions of the CWA Friday night into Saturday morning, but amounts
will be fairly light and the precipitation should be in the form of
rain. The Saturday afternoon through Sunday night time period looks
to be dry with weak high pressure in place. Attention then turns to
an upper level shortwave and frontal boundary forecast to track
across the area, bringing a more well organized area of rain to the
region. Timing continues to be the question, with the Canadian model
being just about 6-12 hours faster than the GFS and ECMWF. Will keep
POPs going during the Monday through Tuesday morning time frame for
now. May see one quarter to one half inch of rain in some locations,
and cannot rule out a period where the rain may mix with snow late
Monday night, with minor accumulations possible. The remainder of
the extended period will be dry with high pressure moving in control
Wednesday and Thursday.

In general, temperatures will be leaning toward a warming trend.
Highs will be in the 50s on Saturday, and in the 50s and 60s Sunday
and Monday. Cooler temperatures move in with the rain Tuesday, with
highs back down in the 50s before warmer air returns, with highs
mainly in the 60s Wednesday and Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1231 AM CDT Fri Apr 20 2018

VFR conditions are expected through most of the TAF valid period.
By late afternoon, some rain showers may be working northward into
the region (mainly affecting KPIR), and after 00Z some sub-VFR cigs
may be developing. Currently, not a lot of confidence in sub-VFR
conditions setting up Friday evening/night. Will continue to




LONG TERM...Parkin
AVIATION...Dorn is the U.S. government's official web portal to all federal, state and local government web resources and services.