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 241547

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
947 AM MDT Tue Apr 24 2018

Issued at 947 AM MDT Tue Apr 24 2018

Current surface analysis shows low pressure over western IA, with
cold front well south and east of the area. Upper level analysis
shows trough axis over SD and WY, sliding slowly to the southeast.
KUDX radar shows lingering areas of light rain and snow across
mainly west central into southwest and south central SD. Some
breaks in the clouds are noted over northeast WY and far northwest
SD as drier air filters in from the northwest. Temps this hour are
mostly in the 30s, with some 40s over south central SD. Brisk
north to northwest winds continue across the SD plains, gusting
to 40 mph over south central SD.

Areas of light rain will continue into the afternoon across the
southern SD plains, with some snow possibly mixing in across the
higher elevations and ridgetop areas of southwest SD. Rain is
still expected to exit south central SD tonight with winds
diminishing late today. Temps will rise into the 40s for highs,
with some 30s lingering across the higher Black Hills. Minor
updates have been made to the forecast to account for current pcpn
trends and cloud cover.

UPDATE Issued at 624 AM MDT Tue Apr 24 2018

Upper low continues to spin over northwest South Dakota with light
rain and snow falling across the area. Looking at webcams across
the Advisory area, light snow continues, with little accumulations
on roadways and little restriction to visibility. Light snow is
expected to continue across the area with little additional
accumulation expected. Therefore the Winter Weather Advisories
for the northern Black Hills and points north have been cancelled.


.DISCUSSION...(Today Through Monday)
Issued at 332 AM MDT Tue Apr 24 2018

Upper level analysis has positively tilted trof across the
northern Plains, with low center over northwestern South Dakota.
Rain showers are pushing east across central SD, while rain and
snow is falling across western SD. At the surface, low pressure
is located across central SD, with high pressure across central
Montana. In between, decent pressure gradient is producing gusty
northwest winds across the forecast area, with some gusts to 40
mph. Temperatures at 3am are in the low to mid 30s, with some 40s
across far south central SD just ahead of the surface front.

Northern stream trof shears out today as closed low over northwest
South Dakota drops southeast into south central SD by late
afternoon. Still looking at another 1 to 2 inches of snow across
portions of northwest South Dakota where temperatures have cooled
sufficiently, and precip rates are the heaviest. Another 1 to 2
inches is likely across the northern Black Hills also where
upslope conditions will hold for a few more hours. Anticipate
canceling the Winter Weather advisory later this morning as
snowfall has not stacked up quite as much as expected. Do not
expect too much more snow to accumulate after sunrise. High
temperatures today will be cool, in the 40s for most locations.

The rest of the week looks to be mostly dry and mild as high
amplitude ridge builds over the Rockies region and generally stays
in place through the weekend. A weak disturbance sliding down the
east side of the ridge could bring a few showers Wednesday night
into Thursday morning over northeast WY and the Black Hills and
some cooler air for Thursday. Fairly breezy conditions are also
expected on Thursday. Temps are expected to be above average this
weekend, with highs mostly in the upper 60s and 70s.


.AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning)
Issued At 455 AM MDT Tue Apr 24 2018

MVFR/IFR conditions will prevail for much of the area this morning as
a storm system moves across the area. Rain and snow will end from
west to east this morning, with some light precipitation lingering
into south central South Dakota this afternoon. As the
precipitation ends ceilings will improve to VFR.




AVIATION...7 is the U.S. government's official web portal to all federal, state and local government web resources and services.