Finally, we are no longer in the meteorological winter. We are in spring, which is from March to May. Last week, the nation was more unified. Unified in the sense of temperature. Most of the US east of the Rocky Mountains had colder than normal temperatures. It snowed and iced in North Texas. The Northeast and Midwest languished in freezes. Even the Western US had more normal temperatures instead of a summer. Of course with all the cold air over the Lower 48, it is much warmer in Alaska and Northwest Canada. All the cold air had to go somewhere and it happens to be us. So, why the cold weather in some areas, while warm weather in others. It is has to do with the upper level pattern.
There is upper level troughing over Northeast Canada and Greenland, which is a positive North Atlantic Oscillation (NAO). It is also the polar vortex, which brings down cold air from Arctic. The upper level ridging over Alaska is the negative East Pacific Oscillation (EPO). The ridging causes cold air to be shunted down south. Freezes can happen when there is a positive NAO and negative EPO, like in January 1962, December 1983, and February 1989.
Here is a 6 to 10 day analog forecast.
2/27/2009-A late February heat wave hits the South and Northeast US. Houston records a high of 85°F on 2/27/2009. Second hottest 2/27 on record.
3/16/1978-A cold mid March cold blast hits east of the Rocky Mountains and Eastern Canada. Houston records a low of 33°F on 2/27/2009.
3/8/1982-A cold early March cold blast hits east of the Rocky Mountains and East Central Canada. Northern New England and Maritime Provinces of Canada are warmer than normal. Houston records a low of 30°F on 3/7/1982.
Some of the analog dates for the 6 to 10 day forecast stands out. Those dates had a cold blast right before or after the date. One of them was a warm one in 2009. Now, let’s look at 8 to 14 days analog forecast.
3/7/1989-America sees an early March cold blast. Houston sees 25°F on 3/5 and 3/6 and 28°F on 3/7, shatter low temperature records for those dates. Night time sees freezes from 3/4 to 3/9.
2/26/1974-A late February cold blast hits America in a La Nina Winter. Houston sees 26°F on 2/25 and 2/26, which are record lows for those dates.
2/23/1976-A late February cold blast hits America in a La Nina Winter. Houston sees 27°F on 2/23, which is a record lows for those dates.
3/26/1982-As El Nino is developing, Southern US is hit by a heat wave in April. Houston records a high of 91°F on 4/5/1982 and 4/8/1982, warmest for 4/5. That week is a roller coaster ride of warm and cold.
Some of the analog dates for the 8 to 14 day forecast stands out. There were mostly cold blasts in some of the dates I listed. One had a heat wave in April, which gave way to cold again. I can this week as a roller coaster as it warms up and cools down. Here are temperature forecast model by Friday of this week.
GFS and NAM are not much different as they have a low of 28°F to 29°F on Friday morning. The Canadian is the warmest at 31°F. That is quite cold for this time of year for Southeast Texas! I think it will be cold this week. Freezing rain and snow is not out of the realm for sure. This is going to be an interesting week.