Area Forecast Discussion
Issued by NWS Rapid City, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KUNR 200440

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1040 PM MDT Mon Mar 19 2018

.DISCUSSION...(This Evening Through Monday)
Issued at 159 PM MDT Mon Mar 19 2018

Broad trough over the region aloft will continue to shift east
tonight. Dry air has advected into the region with drizzle/snow
ending over the western 2/3. Light snow will continue over
scentral SD into this evening, waning toward late evening. Some
freezing drizzle will also be possible there as the mid levels dry
and the low levels remain saturated for a bit with lingering low
level lift. Some patchy fog will also be possible over the SD
plains late tonight. Otherwise, another backside compact impulse
many support a few snow showers across NE WY and then NW SD late
tonight into Tue morning, with some isolated snow showers possible
further south into western SD. Diurnal heating under a lingering
cold pool will support some slight chances for rain/snow showers
from the BH southeast Tue afternoon. Dry weather will prevail Wed
as upper level ridging commences.

Western CONUS trough re-loading will occur toward the end of the
week with local WAA and height rises. This will likely support WAA
rain/snow Thur night (with chances shifting NE in this period).
Deep western CONUS trough will eventually shift east this
weekend, with precip chances increasing across the Northern
Plains, possibly supporting a decent storm system if the trough
ejects in large wave packets.

Temperatures will remain around or below seasonal norms for the
next few days, heavily influenced by the snow pack in place on the
SD plains and lack of sig deep southerly flow. Decent melting
should occur in this period with the warmest temps expected over
the sw third where any snow pack will erode the fastest.


.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1037 PM MDT Mon Mar 19 2018

MVFR/IFR conditions generally east of a line from K2WX-KRAP-KCDR
will move east overnight as VFR conditions over northeast WY
try to spread into western SD. Leftover snow/patchy fzdz over
central SD will shift east. Areas IFR VSBYS due to BR will
develop later tonight into Monday morning, especially over western
SD where clearing develops this evening. Isolated -SHSN Monday
may create localized MVFR conditions. Vast improvement will
overspread most places Monday night.




AVIATION...Helgeson is the U.S. government's official web portal to all federal, state and local government web resources and services.