Arctic Air intrusion for Turkey Day?
For about the past week or so there has been a small murmur of talk among us weather geeks about Thanksgiving week weather. That murmur is growing as the long range numerical weather models have really been consistent on bringing a major cold air outbreak into the eastern U.S. the middle of next week. There have bee differences in timing and magnitude but overall the pattern forecasted has been much colder for that time period. I always caution amateur and profession Meteorologists alike to remember, weather models are called “guidance” for a reason, they are not forecasts! You can set yourself up for a busted forecasted if you treat them as an actual forecast. Great guidance along with a skilled Meteorologist work in tandem to create good forecasts. That all being said we are only a week out and the guidance and pattern recognition along with experience are pointing to a early taste of winter late next week.
First of all two of the short range climate predictors for cold air outbreaks in the eastern U.S. are going negative. The N.A.O. which is the North Atlantic Oscillation and the A.O. the Artic Oscillation. When this two indices go negative cold air affects the eastern United States and the more negative they are the colder it gets.
The GFS model is showing the arctic air building over Canada by tomorrow Friday Nov. 19th.
By the time we hit Thanksgiving morning the Arctic air has mortified slightly as it plunges into the northern plains, upper mid-west and the great lakes regions.
Then by the Saturday night Nov. 27th the eastern half of the country will be completely covered by arctic air all the way down to Northern Florida.
If this cold air moves down like I think it will we could be talking about a severe weather outbreak along and ahead of the arctic front. A small snowstorm on the northwest side of the surface low in the Great Lakes. Then a really cold Thanksgiving weekend for the east coast. In Charlotte high temperatures may struggle to get into the mid-40s for highs Saturday and Sunday after Thanksgiving with morning lows possibly in the low 20s. This is still very far out and the location and timing of all of this will come into better focus as we get closer. One things for sure a large section of the U.S. will have a much colder weekend after thanksgiving, the only question is just how cold?