Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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958 FXUS65 KCYS 062057 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 257 PM MDT Sat Jul 6 2024 .KEY MESSAGES... - Near critical to critical fire weather conditions expected on Saturday for parts of Carbon and Albany County. Red Flag Warnings are in effect. - Multiple rounds of scattered showers and thunderstorms are expected between now and Sunday evening. Some may produce gusty winds or small hail. - Gradual warming trend next week with little to no precipitation chances. Very hot by the weekend. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 300 PM MDT Sat Jul 6 2024 After dry weather for the last several days, we will have a little bit more activity over the next 30 hours or so. GOES water vapor satellite imagery shows a broad trough located along the ND/SD line at this time, with some mid to high level moisture moving into our area from the northwest. Visible satellite imagery indicates some shallow cumulus clouds developing over most of the forecast area with the exception of a narrow area in the southern NE panhandle. As moisture aloft increases, more of these shallow cumulus should be able to deepens and lead to scattered showers and thunderstorms across the area this afternoon. The environment is quite limited at this time though, with SBCAPE only around 500 J/kg at this time mainly due to very limited low level moisture. However, with fairly steep lapse rates and decent shear, storms that manage to develop may be able to produce some isolated hail and gusty to strong winds. This first round will be roughly now through about 03-04z, mainly affecting areas along and north of the North Platte River valley. However, a few storms could creep into the southern NE panhandle towards the evening hours. While the first round will clear out this evening, multiple additional rounds of scattered showers and a few storms are possible through the night. A shortwave will rotate around the broad longwave trough over the north central US tonight, and bring with it some modest synoptic lift and a surface cold front. The front will sweep through this evening, and the environment behind will be more moisture rich than the preceding environment. This should keep some echos on the radar through the night. By Sunday morning, the lower atmosphere trough axis and frontal boundary will push through the area. Convergence in the 600 to 700-mb layer will help to kick off another round of showers and thunderstorms mainly along the I-80 corridor from Cheyenne eastward. This activity will continue through the afternoon and spread northward. Overall, Sunday will be quite cool for this time of year with temperatures running 10-20F cooler than average. Monday looks much drier with warmer temperatures moving in aloft stabilizing the atmosphere while PW values drop below average. Temperatures will still be cooler than average Monday, but we will begin the warming trend that will continue through the week ahead. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Issued at 300 PM MDT Sat Jul 6 2024 A warm and mostly tranquil week is expected for southeast Wyoming and western Nebraska as an upper-level ridge slowly moves overhead. Tuesday will be the coolest day in the long term as northwesterly flow remains aloft due to the upper-level ridge still off to the west. This cooler flow will turn more northerly Tuesday evening into early Wednesday morning as the ridge continues to push in from the west. Despite this cooler flow, 700mb temperatures will increase into the 12-15C range, leading to a relatively average day. Highs in southeast Wyoming will range from the low-80s to low-90s near Torrington with western Nebraska in the upper-80s to low-90s. 700mb temperatures slowly tick up for Wednesday, ending near the 14-18C range. Highs on Wednesday will be in the low-80s to low-90s across southeast Wyoming and upper-80s to low-90s across western Nebraska. The warming trend continue through the remainder of the week as the upper-level ridge moves overhead and remains nearly stationary through the weekend. The warmest day is expected to be Saturday, with highs in the low-90s to low-100s across southeast Wyoming and upper-90s to low-100s in western Nebraska. Several days will feature extremely warm temperatures from Friday onwards, so heat headlines may make an appearance next week. As for precipitation chances, this looks to be a very dry and hot week. The best precipitation chances will remain confined to the mountains with portions of Laramie County potentially seeing some light showers. At this time, several vorticity maxima will traverse around the ridge, leading to some lifting across the region in the afternoons. These could provide just enough lift to get shower or thunderstorm development most of the afternoons this week. Kept precipitation chances low, around the 15-20% range, as dewpoints will not be supportive of decent precipitation chances across the region. There is the potential for better precipitation chances over the weekend, as the ridge is progged to weaken slightly and come more flat. However, this is still several days out and precipitation chances remain low at this time. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1128 AM MDT Sat Jul 6 2024 VFR conditions expected for the forecast period. Afternoon convection will be more active today than the last few days, kicking off after about 21-22z. Maintained VCSH for all terminals, except for VCTS at KCDR and KAIA where higher instability will lead to a better thunderstorm chance. Thunderstorms should wane by around 06z, but scattered showers are expected to continue through the night and into Sunday morning. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Red Flag Warning until 8 PM MDT this evening for WYZ425-428. NE...None. && $$ SHORT TERM...MN LONG TERM...AM AVIATION...MN