SNOW AND COLD MONDAY
The cold pattern continues but big changes are coming this week.
After early morning snow Monday, temperatures have been hovering around 40-degrees, the normal for February 21. And a full 20-degrees below normal. This is the 7th straight day below normal and our chilly spring rolls on.
Currently (Spring 2018) ranks among the coldest 22% on record. Since March 1, there have only been two 60-degree days, fewest since 1984!
The early AM snow - another April snow seem to be all too common. This is the first time in over 30 years that a sticking snow fell on April 9. Do date, April alone has produced 2.3" of snow and it has snowed 6 of the 9 days so far this April!
WHAT'S BEHIND THE COLD?
To understand why we are cold, use this simple equation: AO + NA = Below.
We've been having fun with this this afternoon because it has been a long and rather frustratingly cold spring.
What does it mean?
AO= The Arctic Oscillation. Simply put, it's a bubble of warm upper level air (high pressure) that has been stuck in the arctic. This stubborn high created a very wavy jet stream and delivers unusually warm air across Alaska. Today, it was warmer in Juneau than in Indianapolis!
Below the observed and forecast of the Arctic Oscillation. The downturn or negative spans refer tot he cold air evacuating or departing the arctic. Note the huge downturns in early March and the persistent negative readings into April. These correlate with our cold spring to date.
NAO= The North Atlantic Oscillation. On the other side of the continent and extending at times into Greenland, this upper high sends warmth to Greenland and creates a 'block' that doesn't allow milder air to reach the east-half of the nation. Often the sharp dig of jet stream, a result of this blocking allows powerful storms known as nor'easters to develop. There were four of theses storms in less than four weeks earlier in March, bringing incredible amounts of snow, wind and high surf from the mid-Atlantic states into New England.
These cold weather indicators when negative are a strong signal that colder days are coming. And they have, for the sixth straight week we are cold. Spring 2018 has only produced 2 60-degree days, 13.9" of snow and 70% of the days have been below normal.
NOW A WARM UP
Warmer days coming! A strong warm-up to 70s will arrive by late week and Friday and could produce our first 80-degree day of the year! The warm-up comes ahead of a potential whopper of a spring storm that is expected here Saturday. Warm, southwest winds will lock in mid-week and temperatures will surge to end the work week. We will be watching carefully for the potential of heavy rainfall and a multi-day severe weather outbreak that may include Indiana Saturday. We will monitor.