FXUS63 KUNR 071115

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

515 AM MDT Mon Apr 7 2025



.KEY MESSAGES...



- Chance for showers and a few thunderstorms Tuesday afternoon,

  stronger showers/storms may be capable of gusty winds



- Elevated fire wx possible through the late week as unseasonably

  mild temperatures and dry conditions develop



&&



.DISCUSSION...(Today Through Sunday)

Issued at 250 AM MDT Mon Apr 7 2025



Another calm and mostly clear night has settled across the CWA. 

At this hour, a sfc high sits to our north, centered over MB. The 

backdoor front has nudged into the CWA with a narrow band of low 

stratus/patchy fog beginning to develop across central SD. Low 

confidence in any widespread fog development this morning as the 

low level moisture isn't really there to support it. Mild and dry 

conditions on tap for today with highs in the upper 40s to low 50s

across northwestern into south central SD and in the 60s across 

northeastern WY into southwestern SD. 



Upper ridge breaks down on Tuesday as a shortwave develops over 

the Canadian Rockies and digs into the Northern Plains. Attendant 

cool front will push across the CWA late Tuesday evening. Ahead of

the front, marginal instability (around 100-500 J/kg CAPE) should

be enough to trigger the development of isolated thunderstorms

Tuesday afternoon. Though modest 0-6km bulk shear values of 

40-50kt will be present over the region, the lack deep layer 

moisture will be a limiting factor for storm strength Tuesday 

afternoon. Inverted-V profiles indicate that if a storm does

manage to become strong, the main risk would be gusty winds. 

Showery weather persists through Wednesday as active northwest 

flow continues over the region with higher elevations in the Black

Hills potentially seeing some light snow. Most of the region 

should see at least measurable precip from this system with the 

northern Black Hills, far western SD, and northeastern WY 

potentially seeing 0.1+" (40-60% per LREF). 850-700 mb winds of 

30-40kt may mix down Wednesday afternoon, bringing gusty northwest

winds to the western SD plains. 



Ridge builds back into the western US by Thursday, promoting a 

warming trend through the weekend. By Friday and Saturday 

GEFS/GEPS both show high (80-100%) probs of 2m temp anomalies of 

20+F. With the unseasonably mild conditions, dry weather, and 

breezy winds (especially on Thursday), elevated fire wx conditions

may develop later this week.



&&



.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)

Issued At 515 AM MDT Mon Apr 7 2025



Areas of MVFR/IFR conditions can be expected across parts of the 

western into central SD plains this morning, with patchy fog also 

possible, as a backdoor cold front moves into the area. Conditions

will improve by late morning. Breezy southeasterly winds will 

develop across the SD plains late this morning and afternoon. 



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...None.

WY...None.

&&



$$



DISCUSSION/KEY MESSAGES...Wong

AVIATION...26