A cold front is incoming this evening and will cross the area tonight and early tomorrow morning. Showers will accompany this front with heavy rain and possibly a rumble or two in the far south. No severe weather is expected, just heavy rain. Rain will be heaviest in the north where up to an inch is expected. It will be lightest in the south where some areas may only pick up a quarter inch. Rain races NE Monday morning with clearing skies and gusty NW winds Monday during the day. Those NW winds will bring much cooler and much drier air in for Tuesday and Wednesday. An approaching front will bring SW winds and warmer air for late week with showers possible by the upcoming weekend. Just as a reminder, current information on tropical weather is now on the new tropical weather page.
Today’s forecast worked out pretty well and the only glaring error was that there was more sunshine than expected. So far I haven’t received any complaints about that! Clouds are still slowly filtering in from the west while the Midcoast got their predicted marine fog. Temps look good with the only glaring error being lower temps (60’s) along the midcoast where the fog hasn’t let up. I have doubts about the 88 degree reading in Concord as no other station in that area is above the low 80’s but if that is actually accurate, that would be the other mistake as far as temps go. Overall, I’m pretty pleased with today’s forecast.
A deep trough is located over the Great Lakes this evening with an associated surface low near the SE corner of Hudson Bay. Ahead of the trough, strong blocking ridging exists over the Canadian Maritimes. In between, SW flow is bringing warm moist air northward. Strong NW flow behind the trough and attendant front will bring cool, dry air sourced from Northern Canada before SW winds ahead of the digging trough in the Pacific NW bring warmer air for the upcoming weekend.
In terms of what to expect tonight, showers are just now moving into far Western VT which means that western NH will start to see drops in 2-3 hours. It won’t be until well after dark that western Maine starts to see the rain move in. The rain will be associated with a single N/S band containing heavy rain and possibly a rumble or two in the far south. The band will be wider and heavier in northern areas resulting in higher totals there. The HRRR map above illustrates the setup well. The map is valid at 4:00 tomorrow morning. Rain will move out of Portland by 6 AM and out of the midcoast by 8. Clearing will follow.
Behind the front, gusty NW winds are forecast to develop. Winds could gust over 30mph at times as cooler and drier air works into the region. Look for these winds to quickly downslope the coast to sunny skies while upsloping may postpone sunshine for the mountains. Eventually, the air will become so dry that even with upsloping, the mountains will become sunny by afternoon. Dew points are forecast to drop to near 40 by tomorrow night. As winds settle down tomorrow night, temps will fall too. By Tuesday morning, the first fall like chills will be felt with temps bottoming out right around 40 in the north and 50 in the south with very dry air.
Not ready for fall? Not to worry. By late in the week a front will be approaching from the NW and ahead of it SW winds will bring in slowly increasing warmth as well as humidity. While conditions won’t be stifling, the word sticky will once again come to mind by the upcoming weekend. As far as precip goes, the front won’t have a lot of dynamics associated with it and so scattered showers/storms are likely the most we’ll get from that front. After that, dry and warm conditions are likely to kick off next week.
Be sure to check out the new tropical weather page to keep tabs on the Atlantic disturbances 90L and 99L without the hype you may see on social media. The official NHC forecast, my forecast, and links to all the tropical weather information you need to take your own look at the tropics is all there. Check it out!