While the weather is different every day, sometimes it’s easier than others to blog. I usually try to think about what you are talking about with friends or coworkers and write about that or if the weather is dramatic, that ends up stealing my headline. Today there are a few things I hope you will find as interesting as I do. Some of this anecdotal because honestly I don’t have every record at my fingertip so I have to make some educated assumptions about some of my statements.
I thought for example that it’s noteworthy Portland could reach it’s warmest temperatures of the month today, the end of August. This morning I was pondering about how often this happens. (yes I really do think about these things all the time) The reality is the warmest day of August or even summer, probably occurs later more often than I think. The record for today is 98F set back in 1948. That day was the hottest temperature they reached that August. That year, there was 117 degree temperature range in Portland from the coldest to the warmest day over the course of the year. (The chart says 99, but according the NWS is was 98F)
This year, August has been relatively cool in what is turning about to be a cooler year than we have seen in a while. We all know how the chilly weather was especially late this winter and early spring. While we had some heat in July, it wasn’t a terribly warm month and August should end up below average. The image below is a screen shot from the National Weather Service’s site where you can get some recent climate information. Notice how many days have been below average. (those with the minus in front of the number). These averages are comprised of the daytime high and overnight low.
This afternoon a cold front will press eastward and bring an ending to our brief taste of heat. Tomorrow, a cooler and drier northwest flow will usher in Canadian air and drop readings back into the 70s most of the afternoon. Skies will be sunny and the haze and humidity will be pushed out to sea. This nice weather lasts into Saturday.
While the later 2/3rds of the holiday weekend won’t be a washout by any measure, Sunday and Monday also won’t be picture perfect days. The way it appears currently is there will be some sunshine Sunday, especially in the morning. I think clouds build in the afternoon and there is a risk for showers. Monday looks like more clouds than sunshine and the risk of some showers again. It will be humid both days, with Sunday being the warmer (upper 70s) of the two days.
The reason for the uncertainty is a boundary between air masses is going to get hung up around the area. The exact location of the boundary and any energy riding along it will determine the location, timing and intensity of any rain. I’ll refine the forecast as we get closer. You can also find my weather updates on Twitter @growingwisdom
As an aside, hurricane Cristobal is going to pass hundreds of miles offshore the next couple of days. The one impact, though small, will be some swells and rip currents across the south facing coastal areas of southern New England. I don't expect any impact to our beaches, but check your individual beach for the latest warnings.