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Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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023 FXUS65 KCYS 140055 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 655 PM MDT Tue Aug 13 2024 .KEY MESSAGES... - Scattered to numerous afternoon/evening showers and thunderstorms are expected the next few days. Storms will have the potential to produce torrential rainfall, gusty winds, and isolated large hail. - An active pattern continues through the week ahead with near normal temperatures and daily chances for afternoon and evening showers and thunderstorms. - Seasonable temperatures will continue through the period. Showers and thunderstorms will be most likely on Friday, Sunday and Monday, with drier conditions for Saturday. && .SHORT TERM /THROUGH THURSDAY/... Issued at 147 PM MDT Tue Aug 13 2024 Scattered to mostly cloudy conditions are becoming present early this afternoon across portions of the Intermountain West. Weak showers and thunderstorms have initiated as of 20Z across the I-80 corridor and the Front Range of CO. Low clouds from earlier this morning across the Nebraska Panhandle have dissolved late in the morning. There are some concerns with organized, stronger convection initiating later this afternoon and evening due to the prolonged period of cloud cover. This has stabilized the atmosphere in areas that the morning 12Z hi-res guidance progged thunderstorm initiation. The remainder of today we should eventually see more widespread coverage of thunderstorms. The primary concerns will be heavy rainfall, lightning, and isolated hail. Still expecting there to be a prolonged window of convection, but the coverage with the highest intensity of thunderstorms are favored for severe weather in the NE Panhandle. Wetting rainfall greater than 0.10 inches occurring is favored with any slow-moving thunderstorms today, and should assist with the lingering drought concerns. Rain showers and thunderstorms should dissipate for the most part by midnight tonight. Lingering low clouds and light rain may be possible across the I-80 corridor through daybreak. Wednesday will be another day of similar weather conditions. Daytime highs in upper 70s to near 90 degrees are likely for the lower terrain. SLightly cooler temperatures for the mountain zones are anticipated...upper 50s to upper 60s. Showers and thunderstorms are expected to occur during the afternoon and evening hours. Timeline of storms is expected of 18z-6z is favored for Wednesday afternoon and evening. A Marginal Risk of severe wx exists for the entire cwa, along with a chance of excessive rainfall from the thunderstorms that slowly move from west to east. Mild temperatures are forecast on Wednesday night east of the Laramie Range, with a slightly cooler forecast of the upper 30s to upper 40s for areas west of the Laramie Range. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Issued at 221 AM MDT Tue Aug 13 2024 Thursday night/Friday...Some leftover scattered showers and thunderstorms will occur Thursday evening mainly west of a Douglas to Sidney line, with widely scattered showers continuing after midnight across the forecast area. Ridging aloft and drying west winds in the mid levels of the atmosphere will help dry out the airmass somewhat as precipitable water values decrease to 0.4 to 1 inch. Still though, with a surface trough in place near the Wyoming and Nebraska state line, we expect isolated to widely scattered late day showers and thunderstorms most numerous east of I-25. Warmer temperatures anticipated with less cloud cover and with 700 mb temperatures near 18 Celsius, maximum temperatures will be in the 80s. Saturday...West flow aloft will continue to dry out the airmass and thus we will see correspondingly warmer temperatures from the mid 80s to mid 90s. With precipitable water values lowering to 0.3 to 0.7 inches and warm temperatures aloft increasing the convective inhibition. it looks dry. Sunday...Despite ridging aloft developing, we will see an increase in atmospheric moisture content with precipitable water values increasing to 0.8 to 1.2 inches. Thus, we expect an increase in widely scattered to scattered late day showers and thunderstorms, most numerous from the Snowy Range to far southeast Wyoming. Monday...Atmospheric moisture content remains about the same as on Sunday, and thus we expect another round of scattered late day showers and thunderstorms, most numerous near the Colorado state line from the Snowy Range to far southeast Wyoming. With similar 700 mb temperatures, maximum temperatures should be about the same as those from Sunday. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 651 PM MDT Tue Aug 13 2024 A line of thunderstorms continues to move across the southern Nebraska panhandle with gusty winds, heavy rainfall, and lowering flight conditions recently observed near KSNY. While the heaviest portions of the storm has passed, expect MVFR conditions to persist for the next hour or two within the lingering precipitation shield. Additional showers and thunderstorms will be possible for remaining area terminals this evening, but coverage will likely remain isolated through early Wednesday morning. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...BW LONG TERM...RUBIN AVIATION...MB