Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 191138 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
638 AM CDT Wed Apr 19 2017

.UPDATE...
Issued at 632 AM CDT Wed Apr 19 2017

See updated aviation discussion below.

&&


.SHORT TERM...(Today through Friday Afternoon)
Issued at 359 AM CDT Wed Apr 19 2017

Broad area of rain west river transitioning east this morning with
more elevated showers/virga across most of the CWA at time of
issuance. This is the response to an upper wave that will slowly
deepen across the Dakotas today/tonight. The general evolution is
fairly consistent between CAMS with the broad precipitation shield
making a slow transition from southwest to northeast through the
course of the day, with a pivot that will slow the progression of
the whole system. Several CAMS do suggest convection forming to the
south of the CWA and possibly leaking across the border, however
MUCAPE values in the GFS/NAM are generally less than 100j/kg. Thus
will just stick with shower mention.

Otherwise with the widespread cirrus shield already in place, and
only going to increase in thickness - along with precipitation, high
temperatures were essentially the midnight observation or a few
degrees around that.

Rain chances begin to diminish out west this evening, spreading east
overnight. Profiles are mainly supportive of rainfall, and NAM
occasionally drops saturation out of the dendritic growth zone. That
said, profiles for the higher terrain in the east are close, and
wouldn`t be surprised if some non-accumulating snow did actually mix
in.

Clouds persisting overnight will also help limit temperature drop.
There could be some fog on the western extreme of this cloud shield
however, though it is uncertain as to the timing.

The rest of the short term is dry and will be dominated by weak high
pressure that lingers across the region through Friday.


.LONG TERM...(Friday Evening through Tuesday)
Issued at 359 AM CDT Wed Apr 19 2017

Upper level ridging will be over the region when the period begins,
then gets pushed eastward late Sunday night into Monday as a
shortwave trough tracks across the area. A brief period of zonal
flow sets up on Tuesday before another trough approaches Tuesday
night.

At the surface, high pressure will be dominant Friday night through
Sunday, with a low pressure system forecast to track across the
state Sunday night through Monday night. This system will bring a
chance for precipitation to the CWA. Will see a brief respite in the
precipitation Monday night, then another low pressure system will
track across the Central Plains, bringing another chance for
precipitation to mainly the southern half of the CWA Tuesday and
Tuesday night. Instability will be lacking with both systems, so
will keep the mention as rain showers. Cannot rule out a brief mix
with light snow both early Tuesday morning and overnight Tuesday
night.

Highs will be mainly in the 60s Saturday, Sunday and Monday, then
will see cooler highs in the 50s on Tuesday due to more cloud cover
and potential precipitation. Lows will generally be in the 30s, with
the exception of Sunday night when WAA ahead of the approaching low
will only allow temperatures to fall into the lower to mid 40s.


&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 632 AM CDT Wed Apr 19 2017

An area of rain will overspread the region today and will continue
through the evening before gradually coming to an end from west to
east overnight. Cigs will fall to MVFR/IFR levels and vsbys will
fall to MVFR levels with the heavier areas of rain.

&&


.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

SHORT TERM...Connelly
LONG TERM...Parkin
AVIATION...Parkin



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