‘Sneaky’ springtime freezes

If you love to garden, please read on, because this week’s topic is Frost Advisories and Freeze Warnings, and, more specifically, when they are, and are not issued.
Now due to the fact that the last frost or freeze of the season occurs later as you head north and west, warnings from the National Weather Service for “out-of-season” frosts or freezes are also issued later in the season as you head north and west. Unfortunately, this sets up a situation where the NWS may not issue a Freeze Warning for your area, even with a forecast low of 28 degrees, if it is forecast to occur before a particular date.


Let me explain how this can be. Since it is considered possible, based on 30-year averages, that in NW Aroostook County a frost or freeze can occur through June 4, a Frost Advisory or Freeze Warning may not be issued through that date, since having one would be considered “normal.”
Now, for the rest of Aroostook County, based on those same 30-year averages, a frost or freeze can occur through May 24. So, following the same approach as in NW Aroostook, if a freeze is expected, with temperatures in the upper 20s, but it is not yet May 25, a Freeze Warning may not be issued.
So, what can you do before these dates to be aware that you need to protect your garden? Pay attention to the temperature forecast itself!
By the way, in my weathercasts, I like to emphasize frost or freeze risks without waiting for a particular date to do so. But the NWS has guidelines that they must follow. (So don’t blame the good folks at NWS Caribou!)
However, if your phone app is keyed to alert for a Frost Advisory or a Freeze Warning from the National Weather Service, please be aware that for northwest Aroostook, you cannot be assured of the issuance of the advisory or warning until June 5, and in the rest of The County, you cannot be assured of the issuance of the advisory or warning until May 25.
I’d have to say that out of all of the weather topics about which I receive questions, confusion over non-issuance of Frost Advisories and Freeze Warnings generates the most head scratching, because when people see, for example, a map showing a Freeze Warning for all of Aroostook County EXCEPT THE NORTHWEST, they think “Oh, I guess it won’t be as cold there.” Now you know why that is the wrong assumption to make!
Remember, the best thing to do before those dates, June 5th for NW Aroostook and May 25 for the rest of The County, is to pay attention to the temperature forecast itself!
Happy gardening. It was a long winter!
  Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been chief meteorologist at WAGM-TV since 2006. Email him at tshapiro@wagmtv.com.