Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 261945

Area Forecast Discussion
National Weather Service Aberdeen SD
245 PM CDT Wed Apr 26 2017

.SHORT TERM...(This Evening through Thursday)
Issued at 244 PM CDT Wed Apr 26 2017

Upper trof/shear axis will continue to move northeast tonight, with
all the pcpn gradually ending this evening. The rest of the very
short range looks benign with not much in the way of impactful
weather expected. Clouds have begun to erode over the Missouri River
valley this afternoon, but a fair amount of guidance suggests that
the clearing line won`t make it too far east before it slows up, and
perhaps even wiggles back to the west overnight. The main model
blends are trending this way so find no real reason to go against
this thinking.

On Thursday it finally appears as if the clouds will get scoured
out, especially by afternoon.  Thus, temperatures should be
appreciably warmer than the past 24 hours. but still below normal
across the forecast area.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 244 PM CDT Wed Apr 26 2017

Much of the area will be dry through Saturday, with a ridge
extending across from Canada. To start off the period, the initial
sfc low will be exiting across Ontario, with an additional low
across TX. The exception to the dry weather will be our far
southwest counties on the day Friday as the southern low shifts a
trough across KS. The latest trend is to keep much of the
precipitation to our south.

Temperatures will fall into the mid 20s to low 30s Thursday night,
before returning into the 30s from Saturday night through Wednesday
night lows. There is no significant warm up in sight, although near-
normal highs will return Sunday through Wednesday.

There were significant differences between the 00Z ECMWF and 06Z GFS
when we approach Sunday into Monday. The 26/00Z ECMWF continued to
hint at a deeper/more wrapped up system, with the sfc-500mb low
moving across IA by 06Z Monday. 850mb temps in the -2 to -5C range
help support the idea of snow around and east of the I-29 corridor,
on the order of 6 inches at Sisseton. The deterministic EC was one
of the outliers when looking at the Ensemble data, with only 10/50
members indicating additional snow, and the ensemble mean giving
closer to 2-3 inches after these higher values are put into the mix.
The 12Z GFS has come in deeper and with the low now too, with a
roughly 90 mile westward shift to the precipitation shield, still
only clipping our southeastern 4 counties. Will continue to monitor
the forecast trends with this one Sunday night into Monday.

Light rain showers return to central SD Monday night as we remain in
northwesterly flow aloft as the well wrapped up low crosses Upper
MI/Lake Superior. More widespread showers look to slide in Tuesday
night-Wednesday as the next 500mb trough dives across the Northern
Plains through the 4-corners region.


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1227 PM CDT Wed Apr 26 2017

MVFR cigs will gradually dissipate across the region slowly from
west to east through tonight. The snow over the northeast part of
the state should also end in the afternoon or early evening.


SD...Winter Weather Advisory until 7 PM CDT this evening for SDZ006-



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