Drought conditions persist
There is no question that this has been a long, dry summer for the state. The west to east zonal pattern more common in spring and fall has dominated Maine’s weather pattern for months. I have noticed my artesian well pressure has started to slowly drop recently. Folks have voiced their concerns to me on the Pine Tree Weather Facebook Page as the days draw closer to winter.
There is only one part of the region that has not felt the effects of the drought, which is over the northern parts of Somerset County. With the large ridge over the south blocking any influence of southern moisture reaching the northeast, most of New England is feeling it.
It can be taken a step further. A rather significant area of the northeast has endured the effects of long term silent drought for the past three years. From southern New England on up to parts of Maine is down 8-20″+ of rainfall as compared to normal averages. The lack of anything significant in tropical nature since Hurricane Sandy back in October of 2012 has impacted personal water supplies in all of the New England states. This goes far beyond the near surface exceptional drought levels experienced in the region in 2016.
Fire Risk Until Midweek
Maine Forest Rangers have been responding to spotty fires along roadways and in wooded areas all week. Most of the state is at Class 3 – High fire threat with the exception of northern areas. Next door in New Hampshire, they are at Class 4 – Very High for the Great North Woods. With leaves falling, lower dew point temperatures, and lack of any significant rain (1″+) for the southern two-thirds of the state since mid-August, most of the state is a tinder box at this point.
While the temptation is there to start fall cleanups and burn off leaves and brush, it is strongly discouraged. Fireworks usage, along with careless disposal of lit cigarette butts, and campfires are also a potential combustible threat.
Thankfully, the concern diminishes by midweek.
Rain is on the way
The Weather Prediction Center’s idea for rainfall totals through Friday at 8 PM certainly does look promising in the hydrology department. There is still some wiggle-room for where the bulk of the precipitation ends up. One factor is where an approaching long wave trough stalls over the region.
This is something we haven’t seen very often this summer. A river of moisture from the south traveling up the eastern seaboard from the tropics. With this amount of moisture in the air, humidity levels may become a bit uncomfortable, but without the heat, it should be tolerable.
The initial front works into the region late Tuesday into early Wednesday. Scattered showers are possible statewide during the day.
This vorticity (upper level energy) chart shows promise for a soaking rain for Thursday. This depicts what is discussed in meteorological terms as a “negatively-tilted” trough. The bigger precipitation events that occur most anytime of the year is a result of this type of set up. The trough digs deep, a southwest flow ahead of it drags up moisture from the south, low pressure forms ahead of it, and the results are a decent rain, and/or snow/mix event pending on temperature.
Given the high precipitable water levels of the atmosphere, low pressure deepening as a result of enhanced upper level energy, and cold air trailing behind, there is the threat for thunderstorms and heavy downpours with this event. The idea of localized flooding from the heavier rain, ponding on roadways, and leaf-clogged storm drains posing problems in urban areas are all on the table for concerns. Wind appears to play a role in this scenario as well.
It is still early to get into the details, and updates will come in the days ahead.
Always Stay Weather Aware!