FXUS63 KUNR 030908

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

308 AM MDT Thu Jul 3 2025



.KEY MESSAGES...



- Hot with chances for isolated storms this afternoon. A few

  storms in northwestern South Dakota may become strong to severe

  with large hail and damaging winds as the main concerns. 



- Scattered thunderstorms likely on Friday. Severe weather isn't

  expected, though stronger storms could produce heavy rainfall

  and small hail.



- Average to above average temperatures and chances for storms

  will continue through the next week.



&&



.DISCUSSION...(Today Through Wednesday)

Issued at 308 AM MDT Thu Jul 3 2025



Showers and storms are ongoing across northeastern WY into 

western SD. While a few updrafts have pulsed up and produced small

hail and gusty winds, not expecting severe storms to develop from

this activity. The storms have also kicked off a few gusty 

outflow boundaries which are visible on radar reflectivity and 

velocity products. Sfc stations are reporting gusts of 30-50 mph 

associated with the ofb passage. Upper level ridge axis sits over 

the Northern Plains with a weak upper level disturbance cresting 

the ridge over MT/ND. The upper ridge will begin to shift east 

today with a low level thermal ridge developing across the 

Northern Plains. Afternoon temperatures will climb into the 90s 

across the CWA with spots along the western SD plains hitting the 

triple digit mark. Bulk of moisture transport and therefore the 

corridor of highest buoyancy will remain to the east and north of 

the CWA, which will limit overall convective potential this 

afternoon. Increasing height falls and Q-vector convergence ahead 

of a shortwave will support increasing chances for convection 

across northeastern WY, the Black Hills, and northwestern SD later

this afternoon and evening. Modest bulk shear values of 30 to 

40kt could support rotating updrafts and a marginal severe threat.

Deep, well mixed boundary layers and steep low to mid level lapse

rates will support damaging wind gusts and large hail with any 

severe storms that develop.



Shortwave crosses the region Friday, bringing chances for 

scattered thunderstorms across much of the CWA. Temperatures will 

cool off slightly, with highs ranging from the mid 70s across the 

Black Hills and northeastern WY to the upper 80s and low 90s 

across western SD. With weak CAPE (generally below 1000 J/kg per 

HREF probs) and modest shear (30-40kt), severe potential should be

low for Friday. PWAT values of 150-175% of normal will support 

heavy rainfall with storms on Friday.



Westerly, zonal upper flow will develop across the northern tier 

of the US by the weekend. Periodic disturbances moving along the 

flow will bring chances for thunderstorms through this weekend 

into next week. Temperatures will remain seasonable with highs in 

the 80s to 90s. 



&&



.AVIATION...(For the 06Z TAFS Through 06Z Thursday Night)

Issued At 1118 PM MDT Wed Jul 2 2025



Expect isolated/scattered -TSRA over northeastern WY/Black Hills

to slowly move northeast overnight and end around 12z.

Isolated/scattered -TSRA will redevelop Thursday 

afternoon/evening, mainly over northeastern WY/far western SD. 

Outside of -TSRA, VFR conditions will prevail through the period. 

Gusty southerly winds will develop on the western SD plains 

Thursday.



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...None.

WY...None.

&&



$$



DISCUSSION/KEY MESSAGES...Wong

AVIATION...Helgeson