Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 332 AM EDT Thu Oct 17 2024 Valid 12Z Thu Oct 17 2024 - 12Z Sat Oct 19 2024 ...Powerful Pacific storm to bring much colder temperatures and widespread mountain snow throughout the Intermountain West and Rockies over the next few days... ...Heavy rain and scattered flash flooding possible across the southern High Plains on Saturday... ...Above normal temperatures and gusty winds forecast across the central and northern Plains today, resulting in fire weather concerns... As the calendar dives deeper into autumn, colder storm systems are beginning to impact parts of the country along with wintry weather conditions. The Intermountain West and Rockies will face the brunt of next Pacific-bred storm system ushering in below average temperatures, gusty winds, and heavy mountain snowfall. A cold front marching southeastward will mark the sharp transition toward cooler temperatures and increasing snowfall potential. This frontal boundary is anticipated to cross the Intermountain West between today and early Friday before traversing the central Rockies and stalling over the southern High Plains by Saturday. Heavy snowfall is likely in the higher terrain (mainly above 7000-8000 feet) of south-central Montana, western Wyoming, Utah, and southwest Colorado. As the system slows forward progress and increasing moisture content surges up the southern High Plains, the potential for heavy rainfall exists across eastern New Mexico into southeast Colorado. Training north-south oriented lines of showers and storms could contain intense rainfall rates while remaining over similar locations for a few hours. This setup could produce scattered areas of flash flooding, especially for poor drainage locations and urban regions. A Slight Risk (level 2/4) of Excessive Rainfall has been issued for this part of the country in order to further highlight the flooding threat. Additionally, gusty winds are possible in the central Great Basin and Southeast as the strong frontal boundary sweeps through over the next few days, this may also lead to a strong offshore wind event throughout California. Wind Advisories have been issued for parts of Nevada, Arizona, and California, as well as Red Flag Warnings for parts of central and northern California in order to highlight the fire weather danger. Fire weather concerns also exist throughout much of the central U.S. today as strong southerly flow aids in producing above average temperatures and low relative humidity. Red Flag Warnings span from Kansas to Minnesota and reiterate the potential for fires to spread rapidly. These weather conditions throughout the Plains and Midwest are in relation to a potent high pressure system situated over the Ohio/Tennessee valleys that is expected to settled over the East by the end of the week. Underneath this high remains below average temperatures and for some places the first frost or freeze of the season. Low temperatures are expected to drop into the 30s and 40s for a majority of the eastern U.S. outside of the Florida Peninsula, but even northern parts of the Sunshine State may need to break out the sweaters the next few mornings. Temperatures will begin to moderate by Saturday as afternoon highs into the 70s become more widespread. Elsewhere, a separate Pacific system moving inland over British Columbia on Friday will surge precipitation chances into western Washington. Rainfall amounts over 2 to 3 inches are possible in the commonly-damp Olympic Peninsula and northern Cascades. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php