Thursday, May 23, 2013
The march to warm spring weather can often be frustrating and this year is going to bare out that fact. As I review the charts today, one aspect that screams out to me is the lack of any sign of truly mild air for the rest of March. You might ask how I can possibly predict the next two weeks, when we are still unsure of the details for Tuesday’s storm. I’ll provide more information on our next snow event in just a bit. I'll be updating my weather forecast for this weekend and the upcoming storm on Twitter at @growingwisdom please follow me there. Feel free to comment or ask questions too.
The reason I am confident about the chilly second half of the month is that the longer range models are actually quite good at trend forecasting. Think about the last storm that grazed southern Maine. We knew that storm would develop, and most likely miss the area a week in advance. When I look out as far as two weeks, I am no longer focusing on a particular storm, rather I study the jet stream position and configuration. I can often tell that the coming days will be colder, warmer, wetter, drier than one might expect for the time of year.Because the jet stream is forecast to be so far to the south for most of the rest of the month, it raises my confidence level it will be colder than is typical. While the chart shows the average March temperature for Portland, it's important to remember, that averages are just made up of cold springs and warm spring, and few are typical.
This March is going to end up on the colder side of average. Spring can be delayed or sped up by as much as two weeks because of temperature. Plants this time of year are responding to two things, light and temperature. We know that the light will increase predictably until mid-June but the other variable, temperature, varies wildly from year to year. Last March we had days in the 60s and many others well above 50F. These temperatures sped up spring and plants were in bloom far ahead of what had been normally observed. This year, there will be a start difference in when flowers arrive. Some of you, especially over York county, may see a 4 to 6 week difference from last year, mostly for the early blooming trees and bulbs. Once we do warm up in April, the flora will start to catch up to its normal bloom time.
As a small storm zips to our south today some cloudiness will be seen to the south. I expect the least sunshine towards Portsmouth and the most sun furthest north. Temperatures will be cool struggling into the upper 30s. Those of you with the most sun will see the highest readings on the thermometer this afternoon. Overnight will turn clear and cold as readings fall into the teens and 20s in most spots. Sunday abundant sunshine is on the weather menu, but temperatures are going to be only in the mid 30s, more typical of February. The start of the work week will be dry and bright. On Tuesday, there will be a storm moving to our west, while another low forms on the coast. It is this second low on the coast that will cause issues very late Monday night through Tuesday night. First, the storm will bring significant amounts of precipitation to the region. This means that in areas that see snow for an extended period of time, heavy snow is likely. It is quite possible that Portland and parts of the coast are going to get many inches of snow before a possible mix or change to sleet and freezing rain. The Tuesday morning commute looks to be a mess some snow on the ground by then. As much as it pains me to write this, some areas are going to get 6-12 inches of new snow if this storm manifests itself as I suspect it will.
The questions that remain are exactly when does the snow begin? How long does the snow last in each area before a possible change to another form of precipitation. Is freezing rain going to last long enough so as to create dangerous icing that could cause any problems. After the storm ends, cold and dry weather will continue for the rest of the week with temperatures remaining in the 30s. Any new snow we receive will certainly melt, but the process won’t be rapid. When March is finally in the record books it will go down as one of the snowiest and coldest in over a decade.
Gardening this week A very common problem with house plants is aphids. These sucking insects leave a residue on the leaves that can then cause a secondary infection on your plants. If you notice a black shoot-like coating on your houseplants, you probably have black sooty mold. This problem while not generally fatal to a plant can be an indication of an insect infestation. Check out this weeks video on black sooty mold and see if your plants have this issue. I'll be updating my weather forecast for this week on Twitter at @growingwisdom please follow me there. Feel free to comment or ask questions too.Tweet
David Epstein has been a meteorologist for more than 25 years. He spent 16 years in Boston and currently freelances at WGME13 in Portland.
In 2006, David founded GrowingWisdom.com, a business producing educational and marketing videos for the green industry. He currently is a professor at Framingham State College, teaches Jan Plan at Colby College and owns Bloomscapes Inc., a landscape design business.
David authored "Gardens Of New England" and his work has been published in Grolier's Science Annual for 10 years. He lives in South Natick, Mass., and has a summer home in Harpswell.