The low pressure responsible for today's rainstorm has been reminding me of the Blizzard of '78 - at least on the weathermap. Low pressure forming near Florida, bringing a great deal of moisture up the east coast, with cold air from Canada trying to move down at the same time. No storms look exactly the same, but I definitely saw the similarities between today's rainstorm and a situation that us snowlovers pray for, come February. These nor'easters are definitely much more common in winter than in summer, and we've had at least a couple of them this summer.
The rain is almost over. The back edge of it is moving from SW to NE, and most of Massachusetts is now beginning to dry out. We've had just over an inch of rain at Black Cat, which would've been 10-15 inches of snow, maybe 20 if it was cold enough. For the afternoon expect this steady rain to taper off to occasional showers or drizzle (which would've been 'flurries' in winter) but otherwise just cloudy (the part where we all would've gone out to shovel/snowblow/plow.)
Tropical season... I think it's going to be a quiet season. It's been quiet so far. The pattern has favored wintertime features more often than not, this summer. There are many reasons this affects hurricane development. It goes beyond a simple temperature equation. Hurricanes don't need 'just heat.' They are a mix of hot and cold, and the weather around them needs to be just right. For as powerful as they are, they are still very sensitive to things like headwinds and dry air. If dry air pours off the edge of the continent (part of a wintertime pattern) tropical development is probably not going to happen. Wintertime winds over the tropics follow different courses than summertime winds, and this also dictates hurricane development. There are favorable and unfavorable courses. Even the most powerful hurricane can lose a lot of strength when it meets with unfavorable winds. Its circulation may be powerful, but it's delicate and doesn't like to be jostled by outside conditions. Having said all the above, I don't think it will be an active hurricane season because the weathermap has been filled with wintertime features this summer.
Disclaimer: It only takes one hurricane and "just the right steering currents" to make a memorable season. Andrew was the first storm of its season, and that happened in August.
Some are asking, "Why all the hot air in places like the Pacific Northwest, if we're in a wintertime pattern?" Because weather is physics on a very large scale. In summer, the warm air wants to occupy the northern hemisphere evenly, and if it did, we'd be able to predict temperature based on latitude alone. But that's not the case. The earth doesn't heat or cool evenly. That leaves warm and cold air masses. The cold ones are the heavier of the two. Warm air doesn't actually rise - cold air falls because it's heavier. Nothing on earth rises, because gravity is always here. There is warm, and there is cold. One is heavier than the other (cold). Gravity pulls the heavier object to the ground, and displacement forces the lighter object to go somewhere else. Air masses are invisible objects: They bash into each other, one can crush another against a third, and stuff like that.
Perhaps you have noticed, especially in wintertime, that when we in the east are very cold, it's usually warm out west. The cold air masses move southeast from Canada and New England is in the direct path. When the cold air moves southward into warmer territory, the warm air must go somewhere. It may have to go where it normally doesn't want to. Think of it in the same way as when a person canonballs into the lake. Water comes flying UP, above the surface, and for a while the air is filled with blobs of water. That is not a normal situation, but it settles back down again. However, if a steady stream of people continuously jump off the end of the dock, the air in that vicinity will become repeatedly filled with blobs of water. The cold air masses are like people cannonballing themselves off the end of the dock. New England has been where they've been landing all summer long. The warm air ("water") has been splashing up in other locations. It is not as likely that the west coast would get the same cold air masses, because the polar air masses want to move southeastward, and the west coast doesn't have a continent to the northwest. It's a huge ocean. Cold air masses don't stay cold for very long over oceans.
The pattern we've been in all summer would generate a great deal of snow around here in wintertime, and our friends out west would be saying "Where's all the snow?" It happened that way during the winter of 2007-08 when we had all the roof collapses in this area. My friends out west were booking their ski vacations here.
I have seen some info within the last couple days that suggests the larger scale "climatological autumn" got started in early July. This would not surprise me. If true, it would mean that summer gave up, only two weeks after the days peaked in length and started getting shorter again ("First day of summer.") Normally the large-scale climatological autumn gets started in early to mid August. That is when we typically see our first puff of cold/dry air from the northwest. For those of you who were here on July 5, you may remember it looked and felt like "after Labor Day." Typically we do get summer weather after the onset of fall, so summer weather will continue to occur, but I think we're at the peak of it now.
Enjoy whatever we get during the next couple of weeks. It will probably be marked by a great deal of meteorological battle as the cold air remains nearby and is not showing any signs of leaving the warm air alone here.
Eventually, autumn will become dominant, and that will push the battle zone back to our south. That will clear us out. The colder, drier air from the continent will take over again, as we had in April. It might even give us another 90-degree day. If you remember, those 90-degree days in April were not humid ones. It was a continental, not tropical, air mass. Without much humidity (water) in the air to help regulate its temperature, the air was able to change temperature quickly as it does in the desert. When the wind started blowing in from the west, it forced the air to descend in elevation from the inland mountains to the coast. When air descends quickly its pressure increases, and it heats up. The opposite is also true: A can of compressed air will actually get frosty if you discharge it all at once, because the contents inside are rapidly losing pressure. If you ride a fast train through a deep tunnel, you'll notice the air inside starts to get very warm as you reach the lowest part of the tunnel. That's temperature changing in response to a pressure change, and it's much more likely to happen with dry air than with humid air. Therefore we may get another 90-degree day as soon as autumn boots out all this moisture.
Water temperature note: The water temp monitor at the
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