Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 160412
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1012 PM MDT Sun Apr 15 2018

.DISCUSSION...(This Evening Through Sunday)
Issued at 241 PM MDT Sun Apr 15 2018

Upper level analysis has exiting closed low across the upper mid
west with ridge building into the central Rockies. Skies are
mostly sunny across the Dakotas with some cirrus starting to
stream in from the west. At the surface, cold high pressure
continues to persist across the Dakotas, enhanced by significant
snow cover. Temperatures at 3pm range from around 30 in south
central SD, to around 60 in northeast WY.

Warming trend will continue into Monday, especially across
northeast WY and the Black Hills, as ridge shifts east over the
Plains. Highs on Monday will be about 10 degrees warmer in most
areas, though heavily snow covered areas toward south central SD
could remain in the 30s. Breezy to windy south to southeast winds
will develop by the afternoon, ahead of low pressure moving across
Montana.

The next weather system will arrive behind exiting ridge later
Monday night and Tuesday morning. Shortwave will move across the
northern Rockies and into the Northern Plains, along with a cold
front moving through on Tuesday. Areas of rain will develop, with
colder air eventually changing pcpn over to snow later Tuesday and
Tuesday night. The system is progged to intensify as it moves
east of the region Tuesday night, with some enhanced areas of pcpn
toward central SD on the back side. Accumulating snow looks likely
at this point, with the potential for a few inches in south
central SD. Brisk northwesterly winds will develop behind the
front.

A shortwave ridge behind exiting system will bring a period of
mainly dry weather from Wednesday afternoon through the day on
Thursday. However, temperatures will remain below average mid to
late week. Yet another strong system will move across the western US
late in the week, this one further south than previous systems. At
this point, it looks like it will track mostly south of our area,
but at least the northern fringes of the system could bring some
rain and snow Friday and Friday night, especially to southern SD.
There has been a good amount of model inconsistency regarding this
system, so will continue to watch it over the coming days.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Monday Night)
Issued At 1011 PM MDT Sun Apr 15 2018

VFR conditions expected through Monday. Gusty southerly winds
(over 30kts at times) will continue over NE WY and spread into
western SD early Monday.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION...15
AVIATION...Johnson



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