Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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275 FXUS65 KCYS 280516 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1116 PM MDT Thu Jun 27 2024 .KEY MESSAGES... - Scattered showers and thunderstorms are expected across much of southeast Wyoming and western Nebraska this afternoon and evening. A conditional threat for severe thunderstorms will exist across extreme southeast Wyoming and western Nebraska, with large hail and damaging winds the primary hazards along with the potential for an isolated tornado. - Another round of strong to severe thunderstorms is expected Friday as a cold front sweeps across the CWA. At this time, the best chance for convection appears to be in the southern Nebraska panhandle. && .MESOSCALE... Issued at 144 PM MDT Thu Jun 27 2024 Latest GOES WV imagery shows an upper level shortwave moving into central WY with the latest RAP analysis showing the lee trough shifting eastwards towards the WY/NE border. Despite morning dew points east of the I-25 corridor in the upper 50s and low 60s, daytime mixing and westerly winds off the Laramie Range continue to push upper 50 dew points farther east in the NE panhandle near the CWA border with LBF. The placement of this low-level moisture through this afternoon will be important to watch as the atmosphere continues to destabilize as it will have significant impacts on the instability profiles as up to 2000 J/kg of CAPE could be available, but it appears more likely that storms will only be able to tap into ~500 J/kg across the NE panhandle. Latest GOES Daytime Microphysics RGB has shown late morning clearing across the southern NE panhandle and northeast CO with stable low- level billow clouds across much of Platte/Goshen Co where upper level clouds have limited daytime heating. Cu fields have begun developing over the last 30-45 minutes across these areas of clearing which may be an area of concern for stronger storms to develop early this afternoon before the more favorable low-level moisture mixes east. These storms could could produce large hail and strong winds this afternoon before quickly moving east of the CWA into central NE. Will need to continue to monitor for additional Cu development farther north near the Pine Ridge as CAMs have been initiating storms across a localized moisture pool before quickly moving east as well. There is a short window for severe thunderstorms today, potentially ending by 5 PM MDT, with lingering showers and storms through the evening. Looking farther west, much of south-central WY has begun to destabilize as indicated with latest satellite imagery. However, forecast soundings continue to suggest mid-level capping could inhibit deeper convection before better lift arrives from the west. Recent WOFS runs continues to show higher probabilities (40-60%) of strong winds (gusts >58 mph) entering southwest Carbon Co by mid-afternoon with the ongoing convection in the Uintas as it travels east and eventually increasing in coverage through the early evening near the Sierra Madre and Snowy Ranges. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1112 PM MDT Thu Jun 27 2024 VFR conditions expected next 24 hours with isolated thunderstorms during the afternoon Friday. All terminals will see a breezy Friday, as wind gusts of 30-40 knots are expected for most areas on Friday afternoon. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ MESOSCALE...MB AVIATION...GCC