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
42
43
44
45
46
47
48
49
903 FXUS63 KUNR 142056 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 256 PM MDT Sat Sep 14 2024 .KEY MESSAGES... - Very warm through Tuesday with elevated to areas of critical fire weather conditions - A few stronger thunderstorms, mainly afternoon/evening, expected through Sunday - Pattern change mid to late next week with cooler and wetter conditions && .DISCUSSION...(This Evening Through Saturday) Issued at 101 PM MDT Sat Sep 14 2024 Water vapor shows upper trof along the Pac NW coast and southwest flow through the Northern Plains, with distinct short wave over western SD. At the surface, trof extends from southeast MT through west central SD. Active thunderstorms ongoing across portions of western/central SD in association with the short wave. Scattered thunderstorms, a few strong to severe, will gradually shift east of our zones by early this evening. Fairly gusty southerly winds have developed over south central SD early this afternoon, and may increase further this evening as low level jet lifts through central SD. Next short wave arrives later Sunday for another round of thunderstorms late in the afternoon and evening. MLCAPE will be on the order of 1000-2000J/kg along and east of a developing surface trof over far western SD, with just enough shear for a few stronger storms. However, the later nature of storm development could limit the amount of stronger storms. Temps will soar into the 90s south/east of the Black Hills as thermal ridge moves overhead. Another very warm and breezy day expected Monday, but storm chances may be more confined to central SD. Upper trof works through the western CONUS early next week, and into the Plains mid to late week. This will bring a gradually cooling trend along with increasing chances for showers/storms. The first robust wave ejects through our area late Tuesday and Tuesday night for potential widespread precip. The next substantial wave may arrive Friday into Saturday, although confidence that far out not very high. Either way, a definite pattern change to wetter/cooler conditions is on the way as next week progresses. && .AVIATION...(For the 18Z TAFS Through 18Z Sunday) Issued At 1054 AM MDT Sat Sep 14 2024 A few thunderstorms with local MVFR/IFR conditions are possible east of the Black Hills this afternoon and evening. Early Sunday morning, some patchy fog with MVFR/IFR conditions may form across north central SD. Otherwise, VFR conditions are expected through the TAF period. && .FIRE WEATHER... Issued At 256 PM MDT Sat Sep 14 2024 .DISCUSSION...Critical fire weather conditions have developed across portions of northeast WY into southwest SD this afternoon, with southwest winds gusting around 30 mph and RH around and below 10 percent. Conditions should slowly improve this evening. Elevated to near critical fire weather conditions expected again Sunday through Monday (possibly stretching into Tuesday), especially over northeastern WY and far southwest SD where daily minimum relative humidities will dip to 10-20%. The strongest winds both Sunday and Monday look to be east of the Black Hills, so probabilities for widespread critical fire weather conditions over northeast WY and far southwest SD is relatively low at this time, but will be closely monitored. A wetter and cooler pattern is likely to develop mid to late next week. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Red Flag Warning until 7 PM MDT this evening for SDZ322. WY...Red Flag Warning until 7 PM MDT this evening for WYZ315-317. && $$ AVIATION...Pojorlie FIRE WEATHER...Johnson