Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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670 FXUS65 KRIW 302239 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 439 PM MDT Tue Apr 30 2024 .KEY MESSAGES... - Scattered rain/snow showers across western/northern WY during the afternoon and evening today. - Other parts of the state look to remain dry, with gusty winds returning for the afternoon/evening. - Light snow showers possible for western mountains and valleys Wednesday through Thursday. - Another chance for precipitation to end the week, with central and southern WY possibly seeing light snow Friday morning. && .DISCUSSION... Issued at 109 PM MDT Tue Apr 30 2024 A cold front moved through the state last night, which was definitely felt this morning, especially west of the Divide, where places like Big Piney saw morning temperatures in the low 20s. East of the Divide was slightly milder, as breezy winds lingered through the night keeping temperatures from dropping. Conditions look to remain mostly dry today with an upper-level low staying north of WY. The main concern today will be near elevated fire weather conditions, as a potent upper-level jet crosses over the area. This will aid in mixing down strong winds with wind prone areas seeing a (40-70%) of seeing 40+ mph gusts. Other parts of the state likely see breezy conditions as well, with a (30-60%) chance of seeing gusts of 30 mph. RH values will also be rather dry with percentages around 15-20%. Temperatures are forecast to remain cool, with highs around 5-10 degrees below normal, which will limit any rangeland fire danger statements from being issued. Most of the state is expected to remain mostly dry with the exception being northwestern/northern portions of the CWA. These areas have a (20-40%) chance of seeing a brief shower during the day Tuesday. Other parts of the state likely remain dry but an isolated shower cannot be ruled out. The upper-level low that was mentioned earlier will be a key player in the weather across the Cowboy State through the remainder of the week. This low will continue to eject quick moving shortwaves through the region, with the first arriving early Wednesday morning. Impacts look to be minimal with this disturbance having little moisture with it and the track being not very favorable for widespread precipitation. Currently, scattered showers develop Wednesday morning mainly across northern and western parts of the CWA. Due to cold 700 mb temperatures of -5 to -10C associated with this system, snow levels likely lower enough for western valleys to see a brief period of light snow. Jackson Hole and Star Valley look to have a (30-50%) chance of seeing greater than 0.5 inches of snow. Western mountains look to see 1-3 inches of snow by Thursday morning. Highlights are not expected to be issued, due to the low impacts and snow accumulations. The remainder of the state likely remains dry through Wednesday and Thursday, with a (10-30%) chance of seeing a brief shower over that period. The next chance for widespread precipitation arrives Friday. The northern upper-level low is finally pushed east and behind it comes a quick hitting shortwave that moves through the state. Early indications show impacts from this system remain across the lower half of the CWA. There does seem to be a potential for low elevation snowfall depending on the timing of this disturbance. 700 mb temperatures Friday morning range from -5 to -8C across this area bringing snow levels ~5000 feet. Models are also trying to indicate a brief period of northeasterly flow develop as this disturbance moves through Friday morning. If this was to occur there would be the potential for a short period of steady precipitation in northeasterly favored areas such as the eastern Winds and Casper Mountain. While significant impacts are not currently expected, there would be the possibility for light snow accumulation in places such as Lander Friday morning. However, it is important to keep in mind that this is very likely to change, as we are still multiple days out and there still is high uncertainty regarding the track and timing of this system. The first weekend of May looks to see a return to mild and quiet weather, as brief ridging redevelops over the region. Temperatures may even return to the upper 60s and low 70s in some areas. This pleasant and mild weather may be short lived, as models are beginning to indicate another disturbance make its way into the area for the start of next week. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 436 PM MDT Tue Apr 30 2024 VFR conditions expected for all TAF sites through the entirety of the period. Gusty winds will diminish towards sunset becoming less than 10-12kts after 02Z through the overnight hours. Mid level clouds and ceilings expected throughout with snow showers expected at JAC after 14Z coming out of ID for much of the day Wednesday. Nothing significant as VFR expected but with lower ceilings and visibility. Otherwise, lighter winds for Wednesday at all locations less than 10-15kts with no other weather elements expected at this time. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Dziewaltowski AVIATION...Lowe