Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Wed Oct 18 2017 Valid 00Z Thu Oct 19 2017 - 00Z Sat Oct 21 2017 ...Heavy rainfall expected across the Pacific Northwest with snow for the Cascades and Northern Rockies... ...Scattered thunderstorms for Florida and the Southwest to Lower Mississippi Valley... ...Much warmer than average for the central and eastern states... A cold front is expected to move onshore into the Pacific Northwest this evening as a strengthening upper-level trough approaches the West Coast. Very moist air associated with this trough will lead to the possibility of locally heavy rain for the Pacific Northwest through Wednesday night. There is a marginal risk of flash flooding in effect there. The front will continue to push east and south over the next couple of days into the Intermountain West and the Rockies. Along and behind the front, snow is expected for higher elevations of the Cascades on Thursday, and spreading into the Intermountain West and Northern Rockies by Friday morning. A stationary front will linger near southern Florida for the next few days. This front and plenty of moisture will lead to scattered showers and thunderstorms across mainly eastern and southern Florida. Additionally, scattered thunderstorms are possible for the Southwest as a weak upper-level trough approaches. These thunderstorms will spread into the Southern Plains by Thursday and into the Lower Mississippi Valley by Friday as the trough moves eastward. In the central U.S., warmth will prevail through the end of the workweek as a warm front lifts north into Canada on Thursday. The Northern Plains in particular is forecast to be up to 25 degrees above average on Thursday and Friday. This plus the dry conditions will lead to an elevated fire risk there. The eastern U.S. will be warmer than average as well, since high pressure centered over the Southern Appalachians will dominate. With the cold front making its way through the western states, high temperatures 10-15 degrees below average are expected for the Pacific Coast on Thursday and Friday and into the Intermountain West by Friday. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php