US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 135 PM EST Wed Mar 06 2019 Valid Saturday March 09 2019 - Wednesday March 13 2019 Hazards:

• Heavy precipitation across portions of the Northeast, Sun, Mar 10.
• Heavy rain from much of the lower and mid-Mississippi Valley into parts of the Tennessee and Ohio Valleys, as well as the interior Southeast into the Southern Appalachians, Fri-Sat, Mar 8-Mar 9.
• Heavy rain across portions of the Central and Southern Plains, into the lower and mid-Mississippi Valley, Tue, Mar 12.
• Heavy snow across portions of the Central Plains, the Middle Mississippi Valley, the Upper Mississippi Valley, and the Northern Plains, Tue, Mar 12.
• Heavy snow across portions of the Central Plains, the Great Lakes, the Upper Mississippi Valley, and the Northern Plains, Sat-Sun, Mar 9-Mar 10.
• Severe weather across portions of the Central Plains, the Lower Mississippi Valley, the Tennessee Valley, the Middle Mississippi Valley, the Southeast, the Southern Plains, and the Ohio Valley, Sat, Mar 9.
• Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Tennessee Valley, the Middle Mississippi Valley, the Mid-Atlantic, the Southeast, and the Ohio Valley.
• Flooding likely across portions of the Southeast and the Mid-Atlantic.
• Much below normal temperatures across portions of the Northern and Central Plains into parts of the upper Midwest, Fri-Tue, Mar 8-Mar 12.
• Much below normal temperatures across portions of the Northeast, the Central Appalachians, the Mid-Atlantic, the Southern Appalachians, the Great Lakes, and the Ohio Valley, Fri, Mar 8.
• Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sun-Tue, Mar 10-Mar 12.
• High winds across portions of the Alaska Panhandle and mainland Alaska, Sat-Tue, Mar 9-Mar 12.
• High winds across portions of mainland Alaska, Sat-Sun, Mar 9-Mar 10; and for the Aleutians, Fri-Tue, Mar 8-Mar 12.
• High significant wave heights for coastal portions of the Aleutians, Fri-Sun, Mar 8-Mar 10.

Detailed Summary: The medium-range period will begin with widespread precipitation moving across much of the western U.S. as an upper-level trough digs into the Pacific Northwest and interacts with a Pacific cyclone moving rapidly inland across the Desert Southwest on Friday and into the southern Rockies Friday night. By Saturday, the center of the cyclone should be moving into the central Plains and be re-energized as it interacts with an arctic front. Models are coming into closer agreement on the track, intensity, and the subsequent evolution of this strong cyclone. It appears that heavy snow will be a distinct possibility from the northern Plains eastward into the upper Midwest during the weekend, with blizzard conditions possible during the height of the storm. In addition, heavy rain is possible near the storm track from Iowa eastward into the upper Midwest during the weekend. Heavy rain along with severe thunderstorms will also be possible through the weekend from the Ohio Valley southward along the mid and lower Mississippi Valley including the interior southeastern U.S. ahead of a strong cold front. Farther north, precipitation ahead of the low pressure system could be heavy over parts of interior New England on Sunday (Mar. 10) where wintry precipitation is also possible. Meanwhile, models are coming into closer agreement on a low pressure wave forming along an arctic front across the central Plains on Friday. Some wintry precipitation can be expected to spread well ahead of the wave from the Ohio Valley eastward across the central Appalachians and into the northern Mid-Atlantic Friday and Friday night. But the precipitation is not expected to be heavy. For the Southwest, moisture from the next Pacific cyclone should reach California by next Monday (although some snow could move across Nevada and Utah as early as Sunday). The vigorous dynamics ahead of the associated upper-level trough will likely result in the rapid intensification of a low pressure system over the southern High Plains by next Tuesday (Mar. 12). It appears that strong thunderstorms and heavy rain are quite possible across the central and southern Plains on Tuesday. Farther north up toward the central High Plains, heavy snow can be expected to develop as the storm intensifies further. Meanwhile, anomalously cold conditions are expected to persist across the northern and central Plains into the upper Midwest through next Tuesday. Much colder than normal conditions will initially affect the Northeast but temperatures are expected to moderate by the weekend. In Alaska, stormy conditions appear to be in the offing as a deep level ridge over mainland Alaska is forecast to break down, opening the door for strong Pacific cyclones to impact the region. Expect high winds and significant waves to impact the coastal extend of Alaska and into the higher terrain of southern Alaska through next Tuesday. In addition, heavy precipitation is expected to reach the south coast of Alaska on Sunday (Mar. 10), spreading through much of the Alaskan Peninsula Monday and Tuesday. Kong