US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 333 PM EST Mon Jan 17 2022 Valid Thursday January 20 2022 - Monday January 24 2022 Hazards: - Heavy snow across portions of the Southeast, the Southern Appalachians, the Mid-Atlantic, the Central Appalachians, and the Tennessee Valley, Thu-Sat, Jan 20-Jan 22. - Freezing rain across portions of the Southeast, the Mid-Atlantic, the Southern Appalachians, and the Tennessee Valley, Thu-Sat, Jan 20-Jan 22. - Flooding occurring or imminent across portions of the Lower Mississippi Valley. - Much below normal temperatures across portions of the Mid-Atlantic, the Lower Mississippi Valley, the Central Appalachians, the Tennessee Valley, the Great Lakes, the Middle Mississippi Valley, the Northeast, the Southern Appalachians, the Southeast, the Southern Plains, and the Ohio Valley, Fri-Sat, Jan 21-Jan 22. - Much below normal temperatures across portions of the Central Plains, the Lower Mississippi Valley, the Northern Plains, the Tennessee Valley, the Great Lakes, the Middle Mississippi Valley, the Upper Mississippi Valley, the Southern Plains, and the Ohio Valley, Thu-Fri, Jan 20-Jan 21. - Much below normal temperatures across portions of the Central Plains, the Upper Mississippi Valley, and the Northern Plains, Thu, Jan 20. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Thu-Sat, Jan 20-Jan 22. - Heavy precipitation across portions of mainland Alaska and the Aleutians, Sat-Sun, Jan 22-Jan 23. - High winds across portions of the Alaska Panhandle and mainland Alaska, Thu-Fri, Jan 20-Jan 21. - High winds across portions of mainland Alaska, Sat-Sun, Jan 22-Jan 23. Detailed Summary: The medium range is best summarized by a strengthening ridge of high pressure along and just off the west coast of North America while a series of upper level disturbances diving south into the Lower 48 carve out a deepening upper trough from Baffin Bay all the way to the Gulf Coast. The predominant hazard in this pattern is bitterly cold temperatures. The aforementioned upper level jet stream pattern dislodges Arctic air and directs it into the central and eastern U.S. late week and into the upcoming weekend. Latest WPC minimum temperature forecasts for Thursday morning dip as low as -10 to -20 degrees from northeast Montana and North Dakota through much of Minnesota and into Wisconsin and Iowa. Frigid wind chills in these locations could range between -30 to -40 degrees. By Friday morning, Arctic air arrives in the Northeast with subzero lows for much of northern New England and Upstate New York. While those are the coldest temperatures observed, daily departures of -12 to -20 are possible from the Southern Plains and Lower Mississippi Valley to the Deep South and southern Mid-Atlantic. The pattern typically favors overall drier than normal conditions for much of the country, but in the southeastern U.S., a passing cold front may produce anafrontal snow and ice in portions of Virginia, the DelMarVa Peninsula, and on south into the Carolinas and southern Appalachians. The front is forecast to stall somewhere off the Southeast coast and across Florida. Meanwhile, the interaction between the polar and subtropical jets lead to an intensifying jet streak across the South. The orientation of the jet streak places its right-entrance quadrant over South Texas and Louisiana on Thursday and its other favorable left exit quadrant over the southern Mid-Atlantic on Thursday too (supporting the anafrontal precipitation). The former is tricky, as there is not much of an organized system, but southwesterly flow aloft overrunning the low level cold plunging south allows for the chance of icy precipitation over the Deep South Thursday into Friday. Should confidence increase over the next 24 hours, a freezing rain/sleet area may be needed for parts of the Deep South for the end of the week. The area with slightly higher confidence (albeit not "that" high given lingering model spread) is the Southeast and Mid-Atlantic. The aforementioned jet streak on Thursday sticks around into Friday with a favorable low level baroclinic environment sticking by close to the Southeast coast. How long the region is under the influence of this potentially wintry setup depends on how a pair of upper level disturbances interact. The Euro ensembles suggest a slower and more amplified look while the GEFS are more progressive, but still wintry nonetheless with just under half of is 12Z members showing freezing rain potential in the Carolina to close out the week. Have introduced heavy snow and sleet/freezing rain areas for parts of the Mid-Atlantic and Southeast where the region may witness potentially a couple days worth of wintry weather. Residents from the northern Mid-Atlantic to southern New England should also continue to monitor WPC and local WFO forecasts in the days to come as a potential for the storm track more up the coast is within the realm of possibility, but still remains uncertain at this time. ...Alaska... The North Pacific jet stream pattern features a deep upper trough southwest of the Aleutians and in the Bering Sea. Farther east, an amplifying ridge is forecast to anchor itself over the western coast of Canada and through the Alaskan Panhandle. On Thursday, ensemble guidance is coming into better agreement that a powerful cyclone south of the Alaskan Peninsula will tap into rich subtropical moisture, leading to a robust Atmospheric River aimed directly at the South Central coast and the northern Panhandle. The southern Panhandle looks to receive heavy precipitation too, but lower elevation rainfall and mountain snowfall totals look to be significant, especially near Yakutat where ensemble guidance is anticipating the highest totals to occur. In addition, strong wind gusts along the coastline and atop the higher terrain are possible with gusts in excess of 50 knots possible Thursday and Friday. By the second half of the period, the upper low south of the Aleutians retrogrades west and positions areas from the Kenai Peninsula on west to the Upper Peninsula more favorable for heavy rain and snow. Gusty winds would also result along the coasts and higher elevations. Overall, a stormy and hazardous five days stretch is on tap for the southern coast of Alaska. In contrast, much of the Interior and Far North can expect drier conditions as well abnormally mild temperatures. Mullinax