Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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
662 FXUS63 KUNR 071813 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1213 PM MDT Fri Jun 7 2024 .KEY MESSAGES... - Showers and storms continue through this afternoon over parts of western SD. An isolated storm or two may be severe. - Near daily chances for isolated for storms/showers continue into early next week. - Temperatures are expected to be at or above normal through next week. && .DISCUSSION...(This Afternoon Through Thursday) Issued at 1136 AM MDT Fri Jun 7 2024 Current Water Vapor and upper air models depict broad ridge over the western CONUS, while an upper low sits over SK/MB with a longwave trough dipping into the Great Lakes region. At the surface, low pressure has moved over the forecast area, with frontal boundary stretching west/east across the region. Current radar has showers/storms mainly over central and south central SD. Temperatures generally sit in the upper 60s and 70s early this afternoon. As mid-level wave treks across the forecast area today, isolated storms are expected to re-develop in the afternoon. CAMS generally show the bulk of expected storms south and east of the forecast area, with our main concern being our south central SD counties. Severe models depict modest to strong 0-6km shear over much of western SD, however the best CAPE (1000-1500 j/Kg) noses up from Nebraska into south central SD. The main concern continues to be capping this afternoon, with CIN values expected in the -50 to -150 j/Kg range. Cannot rule out some storm development in other areas of western SD this afternoon, however given the severe parameters, any other storms will be more pulse like in nature. The threat for storms should be out of the region by 6-7 pm MDT. Weak LLJ set up following passage of the low, and we could see another round of overnight showers develop across parts of western SD. Models are finally starting to agree more on pattern development over the weekend into early next week, with GFS/NAM/Canadian now pointing to the upper low sitting mostly stagnant over the SK/MB region and eventually sliding easterly by mid-week. Another mid- level wave makes its way across the region late Saturday into Sunday, however staying a bit to our south, and given the timing of the wave, unlikely to see any severe potential. Stronger low level winds and decent moisture will allow for near daily potential for showers/storms through Tuesday. As the upper low begins to shift east middle of next week, upper flow becomes more zonal over the region, allowing for a more dry end to the week, with rising temperatures. && .AVIATION...(For the 18Z TAFS Through 18Z Saturday) Issued At 1118 AM MDT Fri Jun 7 2024 VFR conditions are expected through most of the forecast period. Isolated to scattered SHRA/TS will continue through Saturday morning. Stronger storms are possible this afternoon and evening on the South Dakota plains toward the central portion of the state. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...Dye AVIATION...MLS