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
611 FXUS63 KUNR 201710 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1110 AM MDT Fri Sep 20 2024 .KEY MESSAGES... -Very warm today, with strong dry cold front moving through tonight producing gusty northwest winds -Cooler this weekend -Critical fire weather conditions today across parts of northeast WY and southwest SD, with elevated fire weather conditions elsewhere. Elevated fire weather conditions continue through Saturday -Mainly dry conditions for the next week or so && .DISCUSSION...(Today Through Thursday) Issued at 107 AM MDT Fri Sep 20 2024 Water vapor shows upper ridge across the southern/central Plains with trof digging into the Northern Rockies. At the surface, lee trof is deepening across MT, with high covering northeast WY and western SD. Skies are clear and winds light early this morning. Upper ridge will amplify into the Northern Plains today as upper trof continues to dig through the Northern Rockies. Lee trof will deepen further and shift into the western Dakota in the afternoon. Thermal ridge peaking overhead will result in highs in the 80s to lower 90s, warmest east and south of the Black Hills. Upper trof will shift southeast into the Northern Plains tonight, driving a strong a cold front through the region. 3hr pressure rises of 3-5mb will result in period of gusty northwest winds late tonight through Saturday morning and may near advisory criteria, especially along the eastern slopes of the Black Hills. Highs on Saturday will be in the 60s to lower 90s. Surface high settles into the region Saturday night and should result in lows into the 30s from northeast WY through the Black Hills into northwest SD, with 40s further south. Dry conditions with similar highs in the 60s to lower 70s Sunday, warmest in the west as return flow ensues. Another dry trof moves through early next week and will keep temps near average. Models are relatively consistent building a ridge back into the Rockies and eventually the Plains mid to late next week, resulting in a trend to warmer temperatures. Precip chances should remain low for the next week or so. && .AVIATION...(For the 18Z TAFS Through 18Z Saturday) Issued At 1109 AM MDT Fri Sep 20 2024 VFR conditions will continue through the forecast period. Northwest winds will increase tonight behind a cold front, with gusts over 30 knots possible, strongest from KRAP eastward into western SD plains. && .FIRE WEATHER... Issued At 107 AM MDT Fri Sep 20 2024 Very dry air will work back into the region today, especially northeast WY and southwest SD where min RH`s will be well down into the teens. At the same, surface trof moving into the region combined with deep mixing will result in some gusty westerly winds to near and above 30 mph for this same area. The result will be a period of critical fire weather conditions. Elevated fire weather conditions are expected elsewhere. A strong cold front will move through tonight and Saturday morning, resulting in a period of gusty northwest winds and more elevated fire weather conditions. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Red Flag Warning until 8 PM MDT this evening for SDZ320>322-325- 326. WY...Red Flag Warning until 8 PM MDT this evening for WYZ315-317. && $$ DISCUSSION/KEY MESSAGES...Johnson AVIATION...SE FIRE WEATHER...Johnson