Tuesday Afternoon Update - As seen in the tracking maps below (scroll down), the Storm Prediction Center has parts of our area under a "slight risk" for severe weather through tomorrow morning. Showers and storms have been riding that edge 'ring' and firing up in the heat of the day (explained further below). In addition to the temperature/humidity support, there is some upper air energy driving this forward:
SPC - 500mb Chart + Surface Radar - 1:00pm
Notice the upper-air vorticity lobe (the "agitator" for showers and storms) is currently running west of the convection indicated on radar. Don't be surprised to see more storms fire to the west of what's currently going on here. Any thunderstorm will come with the downpours that can once again challenge flood prone areas. You can track the action in the constantly updating maps at the bottom.
A good Tuesday morning to one and all.
Afternoon temperatures are going to start making a run at the 90° each of the next several days. Adding to this will be plenty of humidity, turning this area into a tinderbox for thunderstorms should the right energy come our way.
This is our lot going forward: Heat long since sheltered out west will be leaking east, and the moisture from the Gulf of Mexico fills the eastern half of the country. However, we're still in a climatic time of weak fronts (or no fronts), so it can be a challenge to anticipate storms. Here's part of how we do it.
The large mass of heat in the center of the country is contained underneath a large ridge of high pressure aloft-- denoted by the 500mb model imagery.
I wrote in the numbers on the contours a little larger so you could (hopefully) see them better. A good rule of thumb here is to knock off the "5" on these and get a ball-park value of what the afternoon high temperature will be. That'll put us at least in the upper 80s, with a possibility of the 90s if that ridge holds out. Now, notice further the dip in the contour values over New England. If this map were a river, the stream would be flowing between the two indicated areas. This is where we would first look for traveling caravans of showers.
The next thing we would spot is that all-important 'vorticity' I talk about occasionally. It represents abnormal twisting in the atmosphere that would agitate and provide the spark for storms-- In our energy-rich environment these sort of things are like moths to a flame.
GFS - 500mb Chart
The "stream" initially is oriented just to our north, but the curve eventually bends down through our region. You'll notice the "X"s on the charts... I've highlighted the red blobs of vorticity that are working towards us, both of which will help fire off showers and storms. Despite the way the maps look, I actually think Wednesday is more likely for thunderstorms than today, though both days will present the risks.
Any time we have a heat-wave quality dome high at the 500mb level that gets entrenched for a few days, meteorologists will look to see this stream set-up where vorticity lobes will be rolling down the steering flow around the high itself. Because it's a zone for frequent storm formation, it has been dubbed the "Ring of Fire", which certainly springs a song to my mind :-)
We might as well get a thunderstorm in here every now and then, because that'll be the only thing keeping us from hitting 90.
Oh, and another thing...
Anyone interested in having a good snowy winter this year? (It seems that snow always brings the blog-watchers out of the shadows) ;-)
Well how about this...
The "Farmer's Almanac", using it's nearly 200-year old "secret" formula, has stepped out boldly this year and predicted a "bitterly cold" "piercing" winter with above normal snowfall. They even go so far as to predict a snowy Super Bowl. A lot of the time the Farmer's Almanac transcends normal criticism, where people only recall when they're right and never bother with times they are wrong. I know, I'm jealous. I bet a lot of you reading this hope they are on the money this year. I'm not ready to make my prediction yet by any stretch. Sometimes I'd like to think I know better ;-)
Have a great day everyone!