The ongoing drought mirroring history For those who have been following along, I've mentioned periodically that I began to notice the onset of the drought last fall when we had a dry October after below-average rainfall in the summer of 2024. October is traditionally our wettest month of the year for all but northern areas (July) based on climatology. That red flag has remained in my mind ever since. For southern areas, since May of 2024 (17 months), 12 months have recorded below average rainfall, and of the 5 months that finished above average, only one recorded above average >1", which was May of this year. We all remember how it precipitated every weekend of spring through early June, wiping out tee ball and Little League games, along with other events during that time. It was easy to think that we would head into summer with a surplus in the hydrology department, but that was just an illusion, as most of those rainy weekends were simply a result of bad timing rather than bringing beneficial rainfall. It's not uncommon for summer to be dry, as the usual patterns dictate potluck showers and storms from weak cold fronts colliding with warm, moist airmasses. That favors more rainfall for the north and mountains, with lesser amounts closer to the coast. Although technically we were not in a drought to start the summer, due to the backloaded winter and sufficient rainfall to keep the topsoil moist, what has been noted as a "flash drought" actually began before the summer of 2024. The region was powerwashed with heavy rain, some junk storms, and snow in March of that year, delivering a range of 5¾- 11" of rainfall to the region. That was the last time the region experienced well above-average precipitation. The graphic here, although not perfect, illustrates the harsh reality that most of the region is currently facing. The coastal plain is so far in the hole that it would take roughly 8" of rain in October to begin to fill groundwater resources and 17"+ of rain through December to what NOAA considers as back to "normal". I am being facetious when I mention "normal," as that is subjective to the geological landscape. Some areas can recover groundwater and reservoir levels more quickly than others, depending on the amount of bedrock and glacial silt present in the region. Areas that deal with clay may take a lot longer to recover, as they need to saturate before rainwater can seep through to reach wells. While the wildfires of 1947 come to mind, there are some things to consider there. 1946 was a dry year (roughly 9" below normal for Portland), which continued into 1947 (another 12"+ below normal), which no doubt contributed to the widespread damage when that occurred. In the 17 months from May 1946 through September 1947, Portland recorded 54.95" of precipitation. In the same window between May 2024 and September 2025, 51.45". The present situation is drier now. While the threat of wildfires will continue to be an issue going forward, the number of people living in the region who depend on groundwater resources is far greater, and that is where my concern is greatest. I keep saying that this could get ugly for those relying on well water this winter, and I see no reason to think otherwise. We're looking at the potential for another backloaded winter. Since model predictions indicated a weak La Niña and above normal precipitation last year, which did not materialize, I'm hesitant to trust them yet. To close out, the period between 1946 and 1950 was the driest in the 20th century. Normal precipitation amounts based on the mean historical average are 270.24". The amount Portland received was 178.71", an almost unthinkable 91.53" below the mean average. I am not saying that will happen, but weather history does have a way of repeating itself. Pray for rain. PLEASE REPORT YOUR DRY WELL to Maine Emergency Management Agency (MEMA) ► https://survey123.arcgis.com/.../1fcc8e5619ac4ae48986174b... The more accurate information on drought impacts will help out in the future. Frost / freeze programs ending for the year Frost is in the forecast over the next three mornings as a cool air mass settles in overhead with a clear sky. Some areas will be notified, others will not. For those nurturing crops and flowers, it is essential this time of year to pay attention to overnight low temperatures. The standard for the National Weather Service for issuing frost/freeze products for the past couple of seasons remains consistent. They take the median average date of the first frost and add ten days to it. After that time, they discontinue issuance of advisories and/or warnings. Advisories and warnings have been discontinued in the purple areas for the far northwestern regions. It has ended (October 1st) for the western mountains over to the rest of Aroostook. The foothills and the coastal areas have a couple of weeks left, BUT that changes if a widespread frost/freeze occurs and the NWS offices declare the growing season over. Of course, that is subject to your location. Maine has thousands of microclimates. Some areas are more prone to frost than others. I recall growing up in Yarmouth during the 1970s/80s, when my home would get a hard frost, while Portland's low temperatures would stay above freezing. It is what it is. The rule of thumb here is that if forecast lows are expected in the mid-30s, there is a possibility of locally cooler temperatures and frost. The forecast dew points through Friday morning are expected to range from the upper 20s to the mid-30s, which, with a slight warm bias in modeling, indicates the potential for frost. It's debatable whether or not it could be "growing season ending", and there is a chance for that Thursday morning close to the shorelines. The safe bet is to cover what you have growing if you want to save it. After this round of cool air, temperatures are expected to climb above normal into the weekend, with the next chance for frost later next week. PTW Weather Wall updates 24/7 Your financial support keeps the lighthouse lit |
Mike Haggett
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