Bobby’s Sunday Meteorological Voice Volume 2 Episode 13
“From the Alpha to the Omega” Block: The Ins and Outs of Our Country’s Latest Weather Pattern
Good Sunday morning! I’m Chief Meteorologist Bobby Klark of the #NorCast subsidiary Bobby’s Weather and Meteorologist for the NorEaster Nick page and Central/North Jersey of Norcast. Trying to be every Sunday, I do a blog/editorial on the good, the bad, and the ugly about the media/weather profession. But first…
Fog has us socked in, especially along the Shore from NY Harbor all the way down to Cape May. It will lift as we become partly to mostly sunny, have low humidity, and seasonable for today.
A lot has been said about our current pattern which really has controlled the entire lower 48 of the US. A strong, stubborn high-pressure system is sitting over the Heartland of the country and will not budge. This has created an upper air flow, which for high pressure is clockwise all around it, as far south as the Southern Caribbean (think Bonnie and she moved so close to South America, almost unheard of in the past with tropical systems), through Central America, flowing up off the Baja and the California coast, into the northwest US Rockies, Upper Plains and down southeast to the south of us. SHEW! That’s a lot of ground, water, air, you name it, to cover.
So, the question becomes: How does this happen? Well, we live in the metro areas of NJ, NYC, and Philly, so it’s quite simple: Traffic Jam. Those that frequent the Parkway, Turnpike, especially south of Exit 3 and north of Exit 14, any major interstate or highway (BQE, LIE, Schuylkill. 287, You get the point), understand traffic jams. A whole bunch of people on the road at once slowing us down almost to a stop. Well, we have that in the upper atmosphere at the moment, and we are not the only ones seeing this. Generally, what creates this back up are our friends to the north and east out along the Azore current and over towards Iceland.
See, for us to have a nice, smooth, normal patterns, we need a “happy little east/west flow” (Cue: Bob Ross) to set up so things flow naturally how it is supposed to. BUT, when you get something like a low pressure that moves off the Eastern Seaboard and goes against the current (Salmon?), it gets stuck, and a battleground sets up. Therefore, while it’s battling the current, high pressure in the Heartland is stuck “in traffic” and has nowhere to go.
This whole pattern is called the “Omega Block”. If you check out the picture below/attached, you will see how this works. Think of the Greek letter Omega. It starts as a straight line and then Horeshoes going up and around and down and ending as a straight line. That is what we have here with the straight line moving towards the Pacific Northwest, horseshoeing up and around the Plains, and eventually looping down and straightening out just south of our region. This allows for scorching heat to sit in the center of the country with very little in the way of rainfall, the northwest and northeastern parts of the country generally or at or below normal, and depending on the trajectory of the flow, can be active with rain and storms. Generally, we have lucked out as most of the major severe weather has been to our south, though we have been getting the northern fringes of heavier rain. But overall, we only have seen 1 or 2 days in a row of humid and hot air before going to back down so for us in the summer, it gives us a bit of a break.
Omega Blocks are generally common, no matter the season. The most pronounced ones for us are usually winter and summer. Winter, obviously, because it puts a deep chill down and depending on where the jet stream sets up, could be a clipper every few days bringing several inches of snow with it. In the summer, it all depends, again, on the jet stream pattern. Omega Blocks are most notable for creating “derechos” or long-range gust fronts. This past week, all over social media, was the one that rocked my ole stomping grounds of Sioux Falls, SD with a massive amount of wind out of nowhere with the “green clouds” engulfing the city. You need a lot of speed behind these meteorologically known Mesoscale Convective Systems (MCS), which builds from the beginning of the ridge (going northward around the high-pressure system), to turning the corner to the top of the “ridge” and then falling off the ridge like a barrel heading down a steep slope. Think of it this way us 80s children. You went roller skating most Friday nights (unless you were me, after school Friday, Friday night, Saturday night, etc). You are with a group of 4 people and want to experience what it is like to go faster than the speed you can do by yourself, you get in a horizontal line with one end falling back a bit, and the three people propel the 4th person forward at a much faster speed. See how weather is just like roller skating; it’s totally rad!
This is unprecedented in the length of time this has lasted. As of this blog posting we are going on Day 16. Normally, its usually 7-10 days, and by the looks of the pattern, as of now, we will see at least another 4-5 days’ worth before, if the extended models look correct, all that scorching heat will head our way…
Thank you for joining me this Sunday morning. I hope you enjoyed reading. If you have any comments, questions, or maybe you have a topic that you would like me to explain or cover, you can comment below if you are on social media or you can email me at email@example.com
Have a great day everyone!