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FXUS63 KUNR 152306

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

506 PM MDT Thu May 15 2025



.KEY MESSAGES...



-Very strong northwest winds with gusts in excess of 60 mph 

 expected across much of the western SD plains through Friday. 



-Precipitation will shift back southwest into the FA tonight



-High elevation snow expected in the Black Hill tonight, mainly 

 above 6 thousand feet



-Unsettled pattern continues into next week with another strong 

 low pressure system bringing appreciable rain to the region 

 Sunday and Monday.



&&



.DISCUSSION...(This Evening Through Thursday)

Issued at 213 PM MDT Thu May 15 2025



Deep closed upper low will retrograde back to the west and 

support strong winds, rain, and some high elevation snow tonight 

and Friday. The pattern remains fairly active into next week with 

mean western CONUS toughing supporting another deep low pressure 

system into the region early next week with widespread rains. 

Upper low has begun to shift back west today with backside 

subsidence, pressure falls, and increasing core of strong winds 

aloft supporting increasing winds across the region. Have extended

the high wind warning further SW, including the Black Hills as 

forecast soundings indicate a good environment for for strong 

winds to mix down to the sfc at times. Steep lapse rates, dry air 

system entertainment, and standing wave potential from terrain 

should allow for frequent gusts over 50 mph with some gusts over 

60 and even 70 mph possible, strongest on the NW SD Plains. This 

setup is similar to the Oct 17-18 event from 2012. There will be a

lull in wind this evening at many areas before the stronger core 

of winds push into the area late tonight and downward momentum 

transport ensues. Rain will spread southwest overnight, backing as

far west as northeast WY. Expect that rain will change to snow in

the higher elevations of the Black Hills, mainly above 6 kft 

where a few inches of wet snow will be possible. The wind combined

with the snow could certainly cause localized travel impacts. 

Winds should peak Friday morning with winds slowly coming down 

through the day. Rain will also shift back east and end by evening

most places. Skies will clear out with winds dropping off many 

areas Friday night into Sat morning supporting the formation of 

frost across far western SD and portions of northeast WY. A frost 

adv may certainly be needed. Temps will warm up some Sat, but 

still be below seasonal norms as the next system approaches the 

area. Pos theta-e adv will ensue, supporting chances for showers 

and storms in the afternoon and overnight Sat. As the system 

shifts east, the associated trowel will remain over the region, 

supporting a long duration of rain Sunday afternoon through Monday

night. Models still are indicating widespread amounts over an 

inch across much of the FA, with the highest amounts (over 2 

inches) expected along the eastern slopes of the BH where upslope 

enhancement will be in place. Some high elevation snow will also 

be possible with this system, esp areas above 6kft. Things will 

dry out by the middle of the week, however semi-active westerly 

flow will persists with near daily chances for showers continuing 

along with seasonally cool temps.



&&



.AVIATION...(For the 00Z TAFS Through 00Z Friday Evening)

Issued At 503 PM MDT Thu May 15 2025



MVFR/IFR conditions will continue across northwest South Dakota

and rain persists through the forecast period. The rain will push

south/southeast overnight, bringing MVFR/IFR conditions back

toward the Black Hills area into northeast WY, and along the I-90

corridor in South Dakota. Strong northwest winds will continue

across the area through the forecast period, with gusts to 55 kt

Winds will gradually decrease after 18-19z Friday, although gusts

30-40 knots will persist into the last few hours of the forecast

period.



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...High Wind Warning until 6 PM MDT /7 PM CDT/ Friday for SDZ001-

     002-012>014-025-026-031-032-041-043-044-046-047-072-073-077-

     078.

     High Wind Warning from midnight tonight to noon MDT Friday for 

     SDZ024-028.

     Wind Advisory until 6 PM MDT /7 PM CDT/ Friday for SDZ027-030-

     042-049-074>076.

WY...High Wind Warning until 6 PM MDT Friday for WYZ060.

&&



$$



DISCUSSION/KEY MESSAGES...JC

AVIATION...SE