Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 051704 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1104 AM CST Tue Dec 5 2017

Issued at 1046 AM CST Tue Dec 5 2017

Made a few changes to the forecast for today. Snow is
developing/advecting south into the region earlier than thought so
made changes to the pops. Highs might be a bit optimistic, but
with some warmer readings upstream, will stick with current
forecast. Winds look fine for now.


.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 439 AM CST Tue Dec 5 2017

Will be watching a clipper system drop southeast across the western
and central Dakotas today and into Iowa by tonight. Ahead of this
system, areas of clouds are producing flurries early this morning
and expect this to persist for the next several hours so have
included this in the forecast. The main area of low pressure will
move over north central SD later this afternoon. Somewhat tricky
forecast for today in regards to wind speeds and snow/blowing snow
potential for our west river counties. Rather right pressure
gradient develops on the back side of the low pressure with 0.5km
winds on the order of 50kts. Most of this is showing up over UNR`s
CWA, with our western counties on the fringe. Everything is pointing
at solid strong winds over western SD, but just how far east
advisory speeds progress is tricky, and will all depend on the track
of the low. For now, went with a Wind Advisory for our west river
counties with current wind grids showing criteria being met for the
western parts of those counties. A comparison of all the available
wind grids show this same idea. Thought about a Winter Weather
Advisory for north central SD due to the strong winds and falling
snow combining with snow on the ground to produce some reduced
visibility. Do not have much confidence on impacts from this though
due to uncertainty in winds and the light intensity of snow today.
Also, a nice push of warmer air moves into central SD later today,
with highs reaching the mid 30s for many areas. Will mention blowing
snow in grids and other products such as the NPW to relay threat for
blowing snow. Speaking of the snow, increased POPs today across the
western CWA as there is good agreement amongst the models in there
being a band of light snow across this area today. Accums will
remain light with an inch or two at most expected.

Light snow chances continue on Wednesday across central SD as a
frontal boundary drops south through the area with a reinforcing
shot of cold air. Forcing along this front may bring some light snow
to the region, with minimal accumulations.

.LONG TERM...(Wednesday Evening through Monday)
Issued at 439 AM CST Tue Dec 5 2017

The long term weather pattern remains the same through the entire
period with north to northwest flow aloft. Very large upper level
low pressure troughing will remain over central and eastern Canada
and southward across much of the central and eastern U.S. with upper
ridging along the west coast and inland. As a result, the low level
thermal boundary extending from northwest to southeast across our
region will push back and forth as short wave troughs/clippers move
over from the northwest. Most of the long term looks to be dry at
this time with a few chances of light snow with the clippers early
on and late in the period. The recent snow cover will have some
influence on the high temperatures. Temperatures are expected to
range from the lower to mid 20s east in the cwa to the lower to mid
30s west for Thursday and Friday. The models then all show the ll
warmer air pushing east into the region for Friday night and
remaining into Monday with highs mainly in the 30s and lower 40s.
This may change later especially for the eastern cwa if the trough
to the east builds back west earlier on Monday.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1046 AM CST Tue Dec 5 2017

KABR/KATY will see mostly vfr conditions through tonight.
KMBG/KPIR however will experience a few periods of light snow,
thus a mix of vfr/mvfr vsbys/cigs is expected. That said, an
occasional vsby dip into the ifr range is possible during


SD...Wind Advisory from 2 PM CST /1 PM MST/ this afternoon to 7 PM
     CST /6 PM MST/ this evening for SDZ003-015-033-045.



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