A storm is on the way this afternoon and it’ll run the New England November Gale playbook to a tee.
Low pressure will pass to our west which means we’re on the warm side of the storm and winds will be picking up out of the southeast later this morning.
We had a beautiful sunrise here in Boothbay Harbor but mid/high clouds are quickly obscuring any early glimpses of the sun and overcast skies will be the rule for the rest of the day.
This forecast map shows expected conditions at noon today, by which point rain will be falling in southern NH as well as along the southeast-facing slopes of the mountains where upsloping will be at work with developing southeasterly flow. Temps will be considerably cooler inland (mid/upper 30s) than near the coast (low to mid 50s).
Winds during the morning hours will remain light as we need to wait for the heavier rain to mix down strong winds from aloft.
By the time this forecast map is valid at 5 PM, that process will be underway south of Portland where winds will be gusting over 30 mph. Steady/heavy rain will be falling across the entire area with a few isolated pockets of sleet/snow in the highest terrain.
The storm will peak overnight tonight as bands of very heavy rain with embedded thunderstorms move up the coast from Massachusetts. These showers and storms will tap into the energy of a low-level jet stream just above the surface packing hurricane force winds. Not all of that energy will make it to the ground, but coastal spots especially northeast of Portland are likely looking at 50-60 mph gusts beginning around 7 PM today and continuing through midday tomorrow.
This animation shows forecasted wind speeds from 1 PM today to 1 PM tomorrow. Note the extended period of strong SE winds along the coast starting this evening and continuing into tomorrow before a cold front slowly pushes east and winds shift around to the southwest.
Power outages are likely especially in the usually-prone areas so make sure you prepare today for that possibility.
This forecast loop shows atmospheric moisture content and winds in that low-level jet I mentioned earlier. The strong southerly winds that we’re worried about causing power outages are also bringing a plume of moisture up from the deep tropics. It’s hard to overstate how unusual this airmass will be for our area for this time of year! That moisture will support very heavy rain tonight and tomorrow morning. The Midcoast and southeast-facing hills/mountains should expect 3-5″ of rain from this storm while most of the rest of Maine picks up 2-4″. New Hampshire won’t get the heavy rain for nearly as long tomorrow so will end up with a bit less (1-3″ outside the Whites).
This will provide a very helpful nail in the coffin of our drought, which should prevent substantial river flooding issues. That said, small streams will make a run at their banks tonight/tomorrow morning and the usual poor drainage spots will fill up with water. Keep an eye on that if you’re headed out and about tonight.
Heavy rain and wind will continue tomorrow morning before gradually tapering off from west to east tomorrow midday/afternoon.