716 FXUS01 KWBC 190634 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 233 AM EDT Thu Mar 19 2026 Valid 12Z Thu Mar 19 2026 - 12Z Sat Mar 21 2026 ...An anomalously early and record-breaking heatwave continues to intensify across the Western U.S. and expand east into the Great Plains... ...Wet weather continues for Western Washington; wintry mix expected across the Upper Midwest/Great Lakes to the Interior Northeast... ...Critical Risk of fire weather across portions of the central and northern High Plains... The forecast remains on track for an anomalous, record-breaking Western U.S. high pressure ridge to further strengthen while expanding eastward into Great Plains this week, bringing an almost Summer-like heatwave to the region. Forecast high temperatures the next couple of days will intensify and soar into the 80s and 90s from California eastward through the Great Basin, Rockies, and into the Plains, with 100s for southern California and the Desert Southwest. Numerous and widespread daily and March monthly record highs are likely, with some locations in California already breaking their March monthly records on Tuesday. Many locations across the Desert Southwest are expected to see their earliest 100+ degree day on record. The early, prolonged nature of this heat with limited seasonal acclimation will increase the risk of heat impacts especially among sensitive populations or those without effective cooling, and heat-related Advisories and Warnings have been posted across the Desert Southwest and along central/southern California. Another concern will be rapid snow melt due to the widespread heat, leading to river rises and swift, dangerous currents. While air temperatures will seem warm enough, water temperatures will remain dangerously cold, and anyone entering the water is at risk of cold water shock and hypothermia. The focus for the heat will gradually expand into the Plains this weekend, challenging many high temperature records in the region as daytime highs climb into the 80s, 90s, and triple digits. Meanwhile, along the Eastern Seaboard, temperatures will recover this weekend following a very chilly first part of the week. Beginning today, much of the East can expect a warming trend to take hold of the region, leading to pleasant Spring-like weather by Saturday. A stubborn Atmospheric River along the northern side of the Western U.S. ridge will maintain locally heavy rainfall over the Pacific Northwest through Saturday, which could yield isolated flooding in the upslope section of the Olympics and Cascades. Warm air accompanying the Atmospheric River will keep snowfall limited to the highest mountain elevations, with some lower elevation rain and higher elevation snow also expected into the northern Rockies. A pair of weak Clipper systems will spread a wintry mix from the Upper Great Lakes into the Interior Northeast today and Friday, with some showers and thunderstorms also possible across the Upper Ohio Valley, Mid-Atlantic, and coastal New England ahead of the cold front. While the Plains states will remain dry, lee troughing east of the Rockies continues to support to gusty winds across portions of the northern and central High Plains. As such, a Critical Risk of fire weather (level 2/3) remains in effect for eastern Wyoming today, where Red Flag Warnings are in effect. Asherman/Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$