US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 339 PM EST Wed Dec 29 2021 Valid Saturday January 01 2022 - Wednesday January 05 2022 Hazards: - Heavy precipitation across portions of California, the Great Basin, the Pacific Northwest, and the Southwest, Sun-Tue, Jan 2-Jan 4. - Heavy rain across portions of the Southeast, the Mid-Atlantic, the Southern Appalachians, the Ohio Valley, and the Tennessee Valley, Sat-Sat, Jan 1-Jan 2. - Heavy snow across portions of the Great Basin, the Northern/Central Rockies, and the Pacific Northwest, Mon-Tue, Jan 3-Jan 4. - Heavy snow across portions of the Middle Mississippi Valley, the Great Lakes, and the Upper Mississippi Valley, Sat, Jan 1. - Severe weather across portions of the Middle/Lower Mississippi Valley, the Tennessee Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, and the Ohio Valley, Sat, Jan 1. - High winds across portions of the Southern Rockies, the Southern Plains, and the Southwest, Sat, Jan 1. - Much below normal temperatures across portions of the Plains, the Rockies, the Great Basin, and the Upper/Middle Mississippi Valley, Sat, Jan 1. - Heavy snow across portions of the Alaska Panhandle and mainland Alaska, Sat, Jan 1. - High winds across portions of the Alaska Panhandle and mainland Alaska, Sat-Mon, Jan 1-Jan 3. - High winds across portions of the Aleutians, Mon, Jan 3. - Much below normal temperatures across portions of the Alaska Panhandle and mainland Alaska, Sun-Wed, Jan 2-Jan 5. Detailed Summary: Cold high pressure settles over most of the western two/thirds of the country on New Year s Day. The clear, cold, and dry air will allow temperatures to drop into the low to mid-twenties below zero over the Northern Plains into the Upper Mississippi Valley by Saturday morning. The single-digit temperatures will extend as far south as the Texas and Oklahoma Panhandle, with below zero temperatures extending into the Great Basin. Therefore, an area of Much Below Normal Temperatures extends across the Northern Tier States into the Upper Mississippi Valley and as far south as parts of the Southern Plains and westward into parts of the Great Basin for New Year s Day. Meanwhile, a strong front along the leading edge of the high pressure extends from the Lower Great Lakes to the Southern Plains/Southwest will destabilize the atmosphere producing conditions favorable for severe thunderstorms on New Year s Day over the Lower Mississippi, Tennessee, and Southern Ohio Valleys into the Southern Appalachians and Southeast. Consequently, SPC has issued a risk of severe thunderstorms over the region for Saturday. Furthermore, heavy rain will develop along the front on New Year s Day over parts of the Central/Southern Appalachians into parts of the Southeast. The heavy rain will continue on Sunday over the Mid-Atlantic. Hence, an area of Heavy Rain is on the Hazards Chart from Central/Southern Appalachians, Southeast into the Mid-Atlantic for Saturday and Sunday. In addition, on the northern side of the front near the surface low, Heavy Snow will develop from parts of the Middle Mississippi Valley to the Great Lakes on New Year s Day and is also depicted on the Hazards Chart. One more hazard is associated with the cold high pressure, and that is an area of High Winds over parts of the Southern Rockies/Southern High Plains on Saturday. The high wind is due to the strong pressure gradient between the low over the Lower Mississippi Valley and the area of high pressure on New Year s Day. Not shown on the Hazards Chart, however still worth noting is the strong wind over Lake Michigan on Saturday into Sunday. As the low pressure moves off the coast on Sunday, strong wind will also develop along the Southeast and Mid-Atlantic Coast. On Monday, the strong wind will expand to the Northeast as a very tight pressure gradient develops on Monday. Moreover, as the area of high pressure moves over the Western Gulf Coast, strong wind will develop across the Western Gulf Coast. These items are not hazards per se but need to mention in this discussion. Additionally, an area of deep low pressure will move southeastward out of the Gulf of Alaska, moving onshore over the Northwest on Sunday into Tuesday. As a result, the storm will produce a region of Heavy Precipitation extending from the Pacific Northwest to Central California on Sunday into Tuesday. The precipitation will be snow at higher elevation and rain at lower elevation. As the system moves inland, an area of Heavy Snow will develop over parts of the Northern Intermountain Region into the Northern Rockies on Monday and Tuesday. Over Alaska, an area of deep low pressure over the Gulf of Alaska on New Year s Day will slowly move southeastward into the Pacific Northwest by Tuesday. The pressure gradient associated with the area of deep low pressure will produce an area of High Wind with a wind speed of greater than 50 knots from parts of the Alaska Peninsula eastward to Yakutat on Saturday into Monday. Moisture associated with the low will stream into the Alaska Panhandle on New Yearâ€s Day, producing an area of Heavy Snow over the region. Behind the system, very cold high pressure will build over the Far North producing a frigid Arctic air mass that will spread below normal temperatures across eastern sections of Interior Alaska, much of southwestern and south-central Alaska, and possibly into the Panhandle from Sunday into Wednesday. A second area of deep low pressure will approach the Aleutians on Sunday into Monday, then stall out as a third low moves off the Asian Coast on Tuesday. The area of low pressure will have a strong pressure gradient over the Near and Rat Islands for Monday. Accordingly, an area of High Winds is depicted on the Hazards Chart over the western part of the Aleutians. Ziegenfelder