Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 080518 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1218 AM CDT Sat May 8 2021

Issued at 911 PM CDT Fri May 7 2021

Current forecast is on track, therefore no changes made at this


.SHORT TERM...(This Evening through Saturday Night)
Issued at 625 PM CDT Fri May 7 2021

An upper trof over the Pacific NW will dig into the northern
Rockies tonight, thus crushing the ridge currently over the region.
A couple waves of energy are expected to move across the region this
weekend. The first wave moves into the area late tonight and then
moves across the forecast area through Saturday. Leftover energy
aloft then migrates across the region on Sunday. The main nw/se band
of precipitation is expected for Saturday as WAA/UVM spreads out
across the Dakotas. PWATs are still progged to reach about an 1", so
some decent rain isn`t out of the question, especially in the
baroclinic zone that will stretch from western ND, south through the
middle section of SD. Various CAM solutions suggest upwards of an
inch or more rain is possible, right over the driest areas of NC SD!
Some of the rain will linger into Saturday night, possible mixing
with snow as temps dip into the low and mid 30s. However, coverage
should be on the decrease as the lift comes to an end and moisture
becomes less abundant. Temperatures through the short range will be
well below normal for this time of year due to all the clouds and

.LONG TERM...(Sunday through Friday)
Issued at 625 PM CDT Fri May 7 2021

The period begins with scattered light rain showers (can`t rule out
a mixing in of snow early on too) Sunday morning and early afternoon
across central and perhaps east central SD, as a shortwave across MN
rotates southward and provides some extra lift. Thereafter, sfc high
pressure drops down from North Dakota, bringing drier lower-level
air with it on north/northeasterly winds. Mid-level cloud cover may
hold on through much of the day however, helping to keep
temperatures rather chilly for early to mid May. Highs are expected
to remain in the 50s on Sunday, which is 10 to 20 degrees below
normal. Furthermore, clearing skies and light winds Sunday night
into Monday morning will promote good radiational cooling and thus
below normal low temperatures in the upper 20s to mid 30s.

Much of the remainder of the long term should be dry, with a slow
moderation in temperatures. An initially somewhat stalled out upper-
low across the Northern Rockies ejects east across the Northern
Plains Tuesday evening into Wednesday, and could bring with it a few
showers (generally light, though there may be enough MUCAPE to
generate a few rumbles of thunder as well, especially Wed afternoon
across the eastern CWA). Otherwise, there`s good agreement among
ensembles in the development of an upper-level ridge across the
western US, which slowly shifts east through the week and into the
weekend. This, again, should limit precip chances and eventually
bring back seasonal temperatures or better.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1217 AM CDT Sat May 8 2021


VFR conditions will prevail across the area overnight. An area of
rain will spread from west to east beginning early Saturday morning,
with cigs falling into the IFR/MVFR categories. Periods of MVFR
vsbys will be possible with the rain as well.




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