This morning I find myself listening to the sound of rain and knowing many of you have had to change your plans for today. The current rain is associated with a slow moving cold front and is now interacting with Arthur. This means tropical downpours on and off today. Last night some nasty storms rolled through parts of the area bringing strong winds, frequent lightning and heavy rain. Some hail was reported as well.

Arthur a formidable category 2 Hurricane made landfall on the outer banks of North Carolina several hours ago as the earliest hurricane on record to do so. This morning, they will be able to assess damage. Fortunately, the storm is now going to stay off the coast before making landfall as a weaker hurricane or strong tropical storm in Canada tomorrow.

For us here in Maine this is a rain event. Winds will be negligible, but could be a bit gusty along the coast late tonight. There are warnings high surf along the coast of Maine. Tomorrow, when the storm passes seas will still be very churned up.

For the rest of the region it’s a rainy afternoon and overnight. The map below shows one prediction for rain early this afternoon. Notice the rain from Arthur is south of us, but there is a feeder band of sorts running north from the storm. This is part of the cold front which is now interacting with the storm. This will help to enhance rainfall amounts through the next 20 hours when most of the rain will fall. (until about 3AM). This is why it’s raining in some areas this morning.

I am not expecting widespread flooding from this storm. Yet, any setup like this does provide the opportunity for a lot of water in a short period of time. Therefore, we are under a flood watch. Rainfall will range from an inch to 4 inches across the region with the highest amounts likely in pockets which see thunderstorms.

The map below shows how much rain is expected from this storm. If you review it, you’ll notice there are not widespread 4 inch amounts over land. However, since the amount of water potential is so high and so close, it’s prudent to put that number as the high mark for the storm. Most of us after this is over will likely see 1 to 3 inches of rain with those higher amounts being in pockets rather than widespread.

I would check my sump pump just in case you end up as one of those towns with the extreme amounts of rainfall. Earlier this week Rumford saw over 4 inches of rain in one hour! A few towns away saw half of that. Tropical air masses can provide as interesting a pattern in rainfall as a good winter storm can do for snow.

I think it’s going to be really tough to get the Red Sox game played today. Even if it’s not raining at Fenway by 1:30 PM, it’s very unlikely it won’t be sometime during the game. My hunch is they will postpone it before then, but check with them of course.

This next map shows rainfall increasing in coverage by 6PM. Remember, these are static maps and the precipitation moves. Focus on the widespread rain, not individual holes in the rain.

This whole system rapidly moves east and north of the region by early Saturday. At sunrise just after 5AM there might be some clouds left, but by 7AM or 8AM the sun will be bright and the air will feel a lot drier. Dew points are going to drop by 20 degrees by mid-morning tomorrow, this mean you will no longer feel the moisture in the air. This next map shows how far east the rain will be after sunrise Saturday.


I’ll be updating the forecast @growingwisdom on Twitter.
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High temperatures will reach the upper 70s and lower 80s Saturday and be similar or a few degrees warmer for Sunday. As usual it will be coolest over the mountains and areas that get a sea breeze. Winds will be gusty in the morning along the coast, not a great morning for a boat ride. If you are going swimming this weekend rip currents will be a factor so be cautious.

Have a great 4th of July weekend and Happy Birthday America!