Record-breaking warmth part of the last stretch of January
Thursday, January 19, 2017, 3:09 - The last stretch of January is here and climate outlooks show a very distinct split temperature pattern dominating the west (colder) and east (warmer).
Precipitation will continue to bring significant and much-needed drought relief to areas of the west and southeast, although a change in the circulation pattern during the last week of the month could mean drier weather for the west and south which are in for some very heavy precipitation through January 25.
Below: Accumulated Precipitation through January 25 (Courtesy: National Weather Service)
A wet pattern will continue to affect the west coast this next week with heavy rain and snow. Some areas of coastal Washington, Oregon and California are expected to accumulate anywhere from 5 to 10 inches of rain, while snow will continue to accumulate by the feet in both the Cascades and Sierra Nevada ranges. Good news as well for portions of the southeast, where despite the risk of some severe weather, precipitation will also be plentiful and put a dent in the drought situation.
Split temperature pattern west and east especially during week 1
The western third of the country will continue to experience below normal temperatures for the remainder of the month with the highest probability of this occurring in the Inner Mountain West and Rocky Mountain regions. Continuous precipitation and very cloudy weather associated with the dominant zonal flow seen over the past few weeks will keep daily average temperature values lower. Extreme northern Alaska could also see colder than normal weather over the next few days.
Below: Temperature outlook for temperature outlook for January 23 to 27 (courtesy: Climate Prediction Center)
A very different temperature configuration is expected over much of the eastern half of the country, with a high probability that values will stay above normal especially in the northeast. Temperatures during the initial week (through to January 25) could run 20 to 25oF above normal in some areas of the east and south with a potential for record breaking values in areas of Texas, Louisiana, Alabama, Tennessee, Arkansas and Mississippi.
Below: Temperature outlook for January 25 to 31 (Courtesy: CPC)
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During the closing week of the month, a different jet stream configuration will be in place to bring colder Canadian air and some precipitation to the south. This should produce a significant drop in temperatures across much of the southern third of the country, all the way from California to Florida. Despite the more northerly flow over the northeast U.S., the lack of true arctic air will help keep temperatures above average. Much of Alaska will continue to experience above normal temperatures, with a higher probability of that occurring along the southern coastal areas.
Above normal precipitation will give way to drier weather at the end of the month
A very wet precipitation pattern is expected to continue across much of the U.S. stretching through to January 25 as the zonal flow with a persistent river of moisture continues to enter the west coast. California, and some areas of the northeast have a higher probability of experiencing this wetter weather, although it will also extend to other areas of the west and east.
Both week 1, currently, and week 2 (January 25 to 31) will also be marked by above normal precipitation across much of Alaska as Pacific storms continue to roll into the area.
Below: Precipitation outlook for January 23 to 27 (Courtesy: CPC)
As the month comes to an end a significant change in the circulation pattern is expected to bring drier weather to the west and southeast.
A strong high pressure center will be building along the west blocking incoming Pacific storms, forcing them to override the ridge and enter the continent through northwest Canada and Alaska. Some areas of the Deep South will have a chance to dry out as they also miss the storm track action and experience below normal precipitation during the last week of the month.
Below: Precipitation outlook for January 25 to 31 (Courtesy: CPC)
With the storm track displaced to the east overriding the enormous high pressure ridge positioned over western North America, above normal precipitation should be the norm in the upper Midwest, across the Great lakes and into the northeast. The green swath that extends from Colorado to the northeast in the last precipitation outlook map, is related to a developing Colorado Low that will strengthen and track northeast.
Below: Drought conditions as of January 18
As we approach the end of this first month of 2017, the good news is that drought has been reduced greatly across many areas of the U.S., especially in the west and southeast. Despite the very active weather expected this coming week across the west and southeast, some additional rain and snow will certainly help put an end to existing drought scenarios.