Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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
931 FXUS65 KRIW 121029 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 429 AM MDT Fri Jul 12 2024 .KEY MESSAGES... - Another day of hot temperatures. - Isolated showers and thunderstorms may bring strong outflow winds gusting 50 to 60 mph this afternoon and evening. - Elevated to near-critical fire weather conditions are expected through the weekend. - Temperatures remain hot through the weekend, then cool slightly for early next week. && .DISCUSSION... Issued at 423 AM MDT Fri Jul 12 2024 Not a whole lot of change in the forecast today - it will be another hot one. The strong ridge remains in place, now centered over southern Utah. Highs will again peak into the upper 90s or lower 100s east of the Continental Divide and lower to mid 90s west. That`s good for around 10 degrees above normal for this time of year. One potential difference today may be slightly increased coverage of showers and thunderstorms this afternoon and evening. The best chance for this activity will be across northern Wyoming owing to a weak shortwave rotating through the flow. This area will also benefit from higher moisture availability. Additionally, we expect more cumulus buildup west of the Divide today, with an isolated shower or storm possible (less than 10 percent for any one location). In reality, most locations will remain dry across the area, with much of the rain evaporating well before reaching the ground given the dry boundary layer and correspondingly high LCLs. As before, the main concern with any showers or storms will be strong outflow wind gusting 50 to 60 mph. With the potential for more convection and outflow, fire weather concerns will be heightened today given the very warm and dry (minimum humidity less than 10 percent) background environment. The heat will continue through the weekend as the overall synoptic pattern remains largely unchanged. Coverage of afternoon convection will continue to trend up as monsoonal moisture is advected into Wyoming. Again, however, the dry lower atmosphere will keep the majority of the area rain-free with the main concern being wind gusts. By early next week the ridge may get flattened somewhat, which will likely provide somewhat of a relief from the heat as well as increased rain chances. Still, ensemble cluster guidance favors continued anomalously high 500mb heights over the region through the end of next week. This would keep temperatures on the warmer side with precipitation chances limited to isolated diurnal convection. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1000 PM MDT Thu Jul 11 2024 VFR conditions will be in place through the TAF period. Mostly SKC skies, with any clouds east of the Divide going away by 12Z. Wind gusts of 20 to 25 kt will return across the forecast area through the afternoon (after 18Z). Any virga showers/thunderstorms will be isolated, with southern and northwestern portions having the best chances. Any convection over the northwest could continue moving eastward over northern portions through 06Z. For now, KCOD and KBPI look to be the main terminals to be impacted by this convection. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts. && .FIRE WEATHER... Issued at 423 AM MDT Fri Jul 12 2024 Elevated to near-critical fire weather conditions are expected through the weekend. Humidity will drop below 10 percent for much of the area today. Wind will be the more limiting factor for a greater risk, though any showers or thunderstorms in the area will have the potential to produce outflow winds gusting 50 to 60 mph. Red Flag Warnings were considered for some of the zones that have fully cured fuels, but confidence on persistent, widespread gusts over 25 mph is not high enough to warrant issuance at this time. && .RIW WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 10 PM MDT Sunday for WYZ004>006-010-011- 017-018-020. && $$ DISCUSSION...Myers AVIATION...LaVoie FIRE WEATHER...Myers