Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 442 AM EDT Sat Jun 06 2020 Valid 12Z Sat Jun 06 2020 - 12Z Mon Jun 08 2020 ...Tropical storm Cristobal is expected to make landfall in Louisiana later on Sunday with heavy rain, squalls, and isolated tornadoes possible... ...A strong low pressure system will keep a good chance of severe thunderstorms across the northern Plains through the weekend... ...Hot weather in the Plains will be contrasted with a dramatic cool down in the West and the possibility of a foot of snow for the higher elevation of the northern Rockies... Tropical storm Cristobal has adopted a steady northward motion across the Gulf of Mexico and is forecast to head toward the central Gulf Coast. Cristobal has a broad and asymmetric circulation with the bulk of the heavy rain falling to the north and northeast of the storm center. Heavy downpours and squalls associated with the outer rainbands of Cristobal are expected to reach many areas along the Gulf Coast later today from Louisiana eastward to the Florida Panhandle and possibly northern Florida. Cristobal is forecast to make landfall on the Louisiana coast later on Sunday as a tropical storm. Increasing winds and waves along with heavy rain will batter the Louisiana coastal sections on Sunday as the core of Cristobal approaches. Some isolated tornadoes are also possible. By Monday morning, the storm should continue to track further inland and begin to weaken. Nevertheless, very heavy rain can be expected to overspread much of the lower Mississippi Valley especially for locations just east of the storm track. Meanwhile, a cold and broad upper-level low is forecast to replace the warm ridge of high pressure that has been anchoring over the western U.S. This system will also engulf an upper-level low coming up across the Desert Southwest and help develop a strong low pressure system across the northern Rockies and northern High Plains during the weekend. This will lead to a heightened chance of strong to severe thunderstorms to move across the northern Plains through much of the weekend ahead of a warm front. The low pressure system will usher in much colder air across the western U.S. Temperatures will be cold enough to support snow from the Cascades to the mountains of northern California, the Great Basin, and especially the northern Rockies. In fact, parts of the northern Rockies in Idaho and western Montana could see heavy snow by Monday morning, where a foot of accumulation is possible. The interior western U.S. should cool down to near normal conditions today, but with critical fire danger continuing for parts of the area. Cooler high temperatures of 15 to 30 degrees below average are forecast to reach the Great Basin on Sunday behind a sharp cold front. Meanwhile, high temperatures into the 90s over the central High Plains are forecast to spread northward into the northern Plains by Sunday ahead of the intensifying low pressure system. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php