Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 229 AM EST Tue Feb 20 2024 Valid 12Z Tue Feb 20 2024 - 12Z Thu Feb 22 2024 ...Heavy rain and heavy mountain snow in California are expected to become less intense... ...A Moderate Risk of Excessive Rainfall remains in effect along portions of coastal southern California today... ...Warming trend expected to expand from the Great Plains into the Midwest through midweek... Heavy rain, snow, high winds and thunderstorm impacts will gradually diminish across California today, as the upper trough supporting them pushes farther inland. A quasi-stationary front will be the focus for additional heavy rainfall over southern California today. A Moderate Risk of Excessive Rainfall leading to Flash Flooding (level 3/4) is in effect for portions of Los Angeles and Orange Counties where between 1-3 inches of rain are possible. Higher totals are expected along the immediate coast and favored terrain of the Transverse Ranges. A broader Slight Risk area (level 2/4) is in effect from Humboldt County down to San Diego, as well as the Sacramento Valley and adjacent upslope areas of the Sierra. Additional accumulations of 6-12 inches of snow are expected for the Sierra, while 1-2 feet are likely over the Shasta Siskiyous today. Persistent troughing and upsloping will support moderate to heavy snow over the Intermountain West where generally between 6-12 inches of snow can be expected. This snowfall is likely to continue into Wednesday and expand in coverage into the Central Rockies. Elsewhere, the ongoing warming trend is expected to continue across the Great Plains and Mississippi Valley through Wednesday before moderating a bit and resurging once again heading into the weekend. High temperatures will be 15-25 degrees above average today and Wednesday over the Great Plains and Mississippi Valley while mild air shift slowly into the Midwest and East Coast. The Florida Peninsula will remain below average temperature-wise due to a deepening upper trough in the western Atlantic. A developing low pressure system will bring showers and thunderstorms to the Midwest on Thursday. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php