Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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706 FXUS65 KCYS 071127 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 527 AM MDT Fri Jun 7 2024 .KEY MESSAGES... - Warm weather will continue through late week, with widespread highs in the 80s and lower 90s Friday. - Threat for strong downburst winds this afternoon and evening from high based thunderstorm development. - Monday and Tuesday will see the greatest coverage of late day showers and thunderstorms, while Wednesday and Thursday will be warmer with a general decrease in shower and thunderstorm coverage. && .SHORT TERM /THROUGH SUNDAY/... Issued at 235 AM MDT Fri Jun 7 2024 Low pressure analyzed over northern Carbon County this morning. Stationary front extends from this low eastward to near Torrington and then into southern Nebraska. South of this front...dewpoints are being observed in the 50s across northeast Colorado into southern Nebraska. Upper shortwave currently located in northwestern Wyoming. Front surges eastward after 18Z today with the surface low located near Chadron. Initial thunderstorms will be high based with GFS soundings showing inverted V soundings and DCAPE near 1000-1200 J/KG. Day crew will need to watch for severe down drafts from these high based storms. Mesoscale simulated radar shows a line of thunderstorms possibly developing across Carbon County after 00Z that eventually move into northern Platte and Goshen Counties before decreasing overnight. After a brief lull in convection...showers and thunderstorms redevelop late Saturday morning into the afternoon as PWATs increase up near 1 inch. ECMWF/GFS/NAM and SREF all painting widespread QPF across southern Wyoming and the southern Panhandle Saturday afternoon. Afternoon instability up near 1200 to 1500 J/KG for the southeast WYoming plains into the Panhandle Saturday afternoon. A Marginal Risk for severe thunderstorms has been highlighted for parts of the CWA. For Sunday...a stronger cold front surges south across our entire northern and eastern CWA as a stronger upper shortwave tracks into South Dakota. 700mb temperatures fall considerably into the single digits with below zero temperatures to near the South Dakota/Nebraska Panhandle state line. Much cooler Sunday which will limit thunderstorm activity. Would envision low stratus and fog across the Panhandle to the east slopes of the Laramie Range with this scenario. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Issued at 235 AM MDT Fri Jun 7 2024 Sunday night/Monday...As daytime heating wanes, isolated to widely scattered showers and thunderstorms will end from west to east overnight Sunday night. West northwest flow aloft develops on Monday, and with plenty of low and mid level moisture available, scattered late day showers and thunderstorms will be on tap again. Temperatures slightly warmer than Sunday with less cloud coverage. Tuesday...Northwest flow aloft remains, though with increasing heights aloft along with warmer temperatures, and a decrease in low and mid level moisture, we should see less coverage of late day showers and thunderstorms. Slightly warmer with more sunshine expected. Wednesday...Even warmer as the flow aloft turns westerly, and with 700 mb temperatures near 15 Celsius, maximum temperatures will be in the mid 80s to lower 90s. Warmer temperatures aloft will increase the convective inhibition, and with less low and mid level moisture around, only a few late day showers and thunderstorms are expected mainly near the mountains. Thursday...Similar synoptic pattern as on Wednesday, though low level winds will become upslope northeast, and with an increase in low and mid level moisture, we expect to see isolated to widely scattered late day showers and thunderstorms. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 522 AM MDT Fri Jun 7 2024 West northwest flow aloft will prevail. Wyoming TAFS...Scattered to broken clouds around 15000 feet will lower to ceilings from 8000 to 10000 feet by this afternoon. Thunderstorms will be in the vicinity from 21Z to 01Z. Winds will gust to 32 knots from 15Z to 01Z. Nebraska TAFS...Scattered clouds around 15000 feet this morning will lower to ceilings from 8000 to 15000 feet by late afternoon. Thunderstorms will be in the vicinity of Scottsbluff and Sidney from 22Z to 02Z. Winds will gust to 25 knots from 14Z to 02Z. && .HYDROLOGY... Issued at 400 PM MDT Thu Jun 6 2024 Several days of above normal temperatures have accelerated snowmelt runoff in the North Platte and Laramie River basins. Temperatures for the next several days are forecast to remain high enough to sustain rapid snowmelt and the subsequent high flows including minor flooding through Saturday. Snowmelt from the Sierra Madre and Snowy Ranges has driven the Encampment and North Platte Rivers to bankfull stages. The Encampment River is forecast to crest above flood stage on Saturday morning. Emergency management has reported minor flooding along the Little Laramie River. This flooding is expected to continue through the weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...GCC LONG TERM...RUBIN AVIATION...RUBIN HYDROLOGY...WFOCYS