Weather Lookup

Key Messages

- widespread rain tonight through early tuesday, with the heaviest totals over central south dakota and northern black hills.

- strong northwest winds monday and monday night. Gusts of 40-60 MPH expected. - rain changing to snow over the higher northern black hills monday evening, with a few inches of snow accumulation.

- drier weather returns later tuesday and remains for the rest of the work week.

Update

Issued at 917 PM MST sun nov 1 2026

04Z surface analysis had low pressure over northeastern co. Water vapour loop had upper trough over the central/northern rockies with powerful 100KT jet ahead of it. 00Z kunr sounding had 1.12" PWAT. Moist for 11/2. Regional radar loop had mainly light precipitation ahead of upper trough. Effect of upper trough the main forecast concern this evening.

Upper trough lifts northeast monday deepening northeastern co surface low as it moves into the eastern dakotas under upper trough/low. Pronounced moisture (pwats forecast 150-225% of normal) transport/lift will support QPF ahead of the trough through monday with deformation zone setting up across northwestern sd monday afternoon/evening. Upslope enhancement for the northern black hills is likely. Pressure gradient tightens considerably with 40-55KT lower tropospheric forecast soundings just east of the black hills into southwestern sd.

The result will be widespread QPF over the cwa with 1/4-1/2" liquid equivalent over the far southwest, 0.5-1.5" east of the black hills, and potentially 2"+ over the northern black hills. Forecast wet bulb zero heights suggest precipitation will change to snow over the northern black hills above 5.5KT later monday afternoon, lowering some monday night as precipitation ends. Latest guidance suggests 3-5" of snow possible above 5.5KT. Will not hoist winter headlines yet given the 25-75th percentile snow is 0.5-5" and the 10-90th is 0-12+", so confidence is very low. Overnight shift and monday day shift can take a closer look. Northeastern wy might even get some accumulation, but minor amounts most likely.

The other result will be northwest wind gusts from 40-60MPH given bufkit forecast momentum transfer, href probabilities, and latest deterministic guidance. Best location for high wind warning would be just east of the black hills into southwestern sd. Surrounded warning with a wind advisory. Headlines and updated forecast out.

Discussion

(this evening through sunday) issued at 234 PM MST sun nov 1 2026

Satellite/wv imagery shows a deep upper trough crossing the western conus, centered across the great basin, with very moist southwesterly flow increasing across the northern high plains. Surface obs show low pressure strengthening across eastern wy into the co front range. Southerly winds extending from tx to the dakotas are pushing in plenty of moisture in the low levels. Still looks like the entire cwa will see precip from early this evening to early tue morning as this large system crosses the north central conus. The three aspects of this storm we are resolving are QPF amounts, snow accumulation, and wind gusts. There is very good model agreement with widespread totals of 0.50" or more across the entire cwa. Models over the last 24 hours have settled on central sd receiving the most QPF, which could reach over an inch and a half or even 2 inches. Also, the northern black hills could see upslope- enhanced QPF exceeding two inches (some models suggest near 3 inches). Most other locations have a good chance of over an inch. This is an impressive system for early november bringing in pwats over an inch...and approaching 1-1.5 inches over the eastern half of sd, which would be considered decently moist for the summer months. Given how dry early november is, that is 2-3 times higher than average. Upcoming soundings will show how well that verifies. Either way, the moisture is there for these high qpfs. Colder air will move in on the backside of the low during the day tomorrow. While the system will remain too warm for widespread accumulating snow, the higher elevations of the northern black hills should see minor accumulations (~2") after rain switches to snow monday evening. Temps will be marginally cold enough in the evening for snow across the NE wy plains, but overall accumulation will be greatly limited by precip ending before sufficiently cold air arrives. However, minor accumulations along higher ridges can't be ruled out. Winds will increase behind the system as well, as the low closes up mon afternoon with gusts of 45-55 MPH or more expected across the NE wy plains and the western sd plains. The question remains just how strong the gusts will end up being. Cams have been showing well above 50KT wind gusts across western sd. Interestingly, the 18Z HRRR has dropped max gusts to 45-55MPH, which is what prior shifts have been settling on. The exception is +50KT winds just east of the black hills into fall river county. This lines up nicely with ensemble guidance. A high wind watch has been issued for most of the western sd plains given the potential for warning-level gusts, although portions of the watch area may ultimately warrant a wind advisory instead. Precip ends tuesday morning, with drier and cooler (but near average) temps through mid week. Winds will be gusty early tuesday but taper off through the day. Quiet weather is expected through the second half of the week.

Aviation

(for the 06Z tafs through 06Z monday night) issued at 1019 PM MST sun nov 1 2026

Widespread MVFR/IFR with local LIFR conditions will continue through the forecast period due to low clouds/fog/precipitation. Rain will pass through the area from southwest to northeast. Some snow will mix with the rain over northeastern wy/higher black hills after 02/15Z. Strong gusty northwest winds will develop monday (especially after 02/18Z) with gusts from 40-55KTS on the open plains, particularly just east of the black hills.