Wednesday, 15 January 2025: 11:15 AM
210 (New Orleans Ernest N. Morial Convention Center)
The extension of the North American monsoon into southern Utah leads to enhanced flash flooding risks to residents and millions of visitors to national parks and monuments during summer. Flash flood reports and Multi-Radar Multi-Sensor (MRMS) lightning analyses across southern Utah are related to atmospheric moisture content, moisture flux, and instability analyses and forecasts from the High-Resolution Rapid Refresh (HRRR)
model during the 2021–24 monsoon seasons. A strong relationship is evident between days with widespread precipitation and afternoons with above average precipitable water (PWAT) and convective available potential energy (CAPE) estimated from HRRR analyses
across the region. Machine learning techniques are applied to time-lagged ensembles of HRRR forecasts (initialization times from 0300 to 0600 UTC) that are 13–18 h prior to the afternoon period when convection is initiating (1800–2100 UTC). Such HRRR predictions may be useful for forecasters at the Salt Lake City and Grand Junction National Weather Service Forecast Offices to assist in issuing flash flood potential statements for visitors to national parks and other recreational areas in the region.
model during the 2021–24 monsoon seasons. A strong relationship is evident between days with widespread precipitation and afternoons with above average precipitable water (PWAT) and convective available potential energy (CAPE) estimated from HRRR analyses
across the region. Machine learning techniques are applied to time-lagged ensembles of HRRR forecasts (initialization times from 0300 to 0600 UTC) that are 13–18 h prior to the afternoon period when convection is initiating (1800–2100 UTC). Such HRRR predictions may be useful for forecasters at the Salt Lake City and Grand Junction National Weather Service Forecast Offices to assist in issuing flash flood potential statements for visitors to national parks and other recreational areas in the region.
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