4:50AM, that’s when I first heard the birds singing this morning. Their songs are quite loud this time of year and I think they were just glad it wasn’t freezing or raining. The weather looks quite nice the next several days as I write from the glass half-full perspective.
Looking at the morning radar there are a few showers moving up from the south but they are widely scattered and most of us are not going to see any rain the next two days. The word shower is in the forecast, a result of some upper level energy which is persistently going to be a factor in the forecast through the weekend.
At 18,000 feet in the atmosphere little disturbances will move over New England and help spawn a few showers. The word disturbance is rather innocuous and tough to explain without a text book. But, think of these perturbations as changes in the direction and speed of the flow of air above us. When the winds undergo sharp changes in direction or speed, it helps create spinning motion. The spin in turn helps lift the air off the ground and giving rise to clouds and forms of precipitation.
If you have ever seen a stick flowing down a river you will notice it starts spinning as it gets into areas where the curve of the river changes or the speed of the water also changes. It’s a similar thing happening in the atmosphere this weekend.
The biggest piece of energy will cross later Sunday and this is why the risk of showers Sunday afternoon is highest.
The map below shows where some of this spin will be occurring Sunday morning. That area will then move eastward over New England during the afternoon and evening. Meteorologists call this spin “vorticity”. You probably can see the word vortex in vorticity and in fact the polar vortex is a larger scale type of spin located at the poles.
So most of you just want to know if it’s going to rain for your golf game, kid’s practices or a barbeque. The highest risk of showers is Sunday afternoon when a majority of us will see at least measurable rainfall. The lowest risk of showers will be Saturday morning when it should be completely dry. After 2PM Saturday there is the chance of a quick shower, but when the day is over, there will be significantly more of us who didn’t see any rain.
I’ll update the foreacst on Twitter @growingwisdom.
Temperatures throughout the weekend average in the 60 to 68 degree range with the warmest day being Saturday thanks to more in the way of sunshine. Sunday is cooler, a result of more clouds and a sea breeze.
Another way to look at the weekend weather is using a meteogram. The graph below provides some rich information about the weather Saturday and Sunday. I put circles around the time when the chance of showers is greatest, Saturday and Sunday.
I also highlighted in a green box the chance of these showers becoming thunderstorm.
After Monday the pattern slowly starts to break and the chance of showers will likely be removed from the forecast. Have a great weekend.