Summer Trough – Good Thing It’s Not February!
A look back toward winter, when the polar jet stream plummeted south into the U.S. and produced a lot of grumpy, frozen people.
Much to the chagrin of many a Meteorologist, there have already been posts online from lord knows who about the ‘Return of the Polar Vortex’ next week. It’s the phenomenon that just won’t die! Of course it became popularized when a very boring and normal weather term was picked up by the mass media this past winter (a sign of how warm our winters have become in general) and communicated across the Earth. Yes, there’s always been a polar vortex. In fact, there are 2 (two poles). And yes, it’s there in the summer too. But it is NOT coming south into the United States next week. What will come on down is a good old fashioned trough which will keep summertime heat at bay for many Americans.
First things first – a nice cold front has passed through much of the region since last night. This will finally get a little push off the southeast coast later today (barely) and we’ll all be enjoying another shot of low humidity and pleasant temperatures. In fact, this upcoming stretch looks great. Low humidity will stay in place through Saturday night, with dew points mainly in the 50s and some low 60s. Pretty easy to take by mid-July standards. It’ll be slightly muggier for the Cape/Islands and South Coast.
Sunday is the warmest day of our forecast, and that’s not saying too much. Highs in the 80s, dew points in the 60s. Nothing too nasty or odd about that this time of year. Overall it’s another outstanding stretch during the weekend – which makes it at least 4 in a row for those of you counting. A couple isolated storms may get here by very late on Sunday but nothing that should disrupt too many plans.
The Climate Prediction Center’s Outlook for days 6-10 (essentially, next week). The darker shades don’t necessarily indicate deep cold, they just indicate a very high probability of below average temperatures. While all this is going on, a very hot and dry stretch will take up residence across the West (in particular the Pacific Northwest).
But back to the topic of a big trough digging in – this will be the story for next week. It is indeed a very similar pattern to what we saw all winter. The core of the ‘cold’ piling on down across the Midwest. Only difference is – this setup in July yields 60s and 70s, not 0s and 10s. Guessing there will be slightly less growling this time around. For those who love heat and humidity it’s not the best, but for those looking to save some cash on the AC bill it’ll definitely help out.
CIPS analogs show a high probability of cool air encompassing a large area of the U.S. next week. Analogs look at the overall setup, run it through a database of past situations, and that creates a number of scenarios and probabilities as to what will happen next. As the saying goes, history tends to repeat itself!
What will this actually look like on the ground? Below I’ve posted the GFS forecast 2m high temperatures for next Wednesday. Obviously, that’s not a set in stone forecast. But basically you see a chance of there being an extraordinarily wide expanse of 70s for highs in the middle of July. Refreshing! This air may make it as far south as Texas before halting its progression. Any big heat will be held to the Gulf Coast and West Coast. On Tuesday highs may not even make it out of the 50s across parts of the northern Great Lakes.
GFS forecast highs for next Wednesday. Source: WeatherBell
As for lows, that’s a little more interesting. Granted, it’s a 6-7 day forecast at this point, so things could definitely evolve differently. But the most recent GFS (ECMWF is similar) has a rather huge area seeing lows in the 40s by next Wednesday morning. Before that, some 30s are even possible near the Canadian border Tuesday morning! That’s rare air, folks.
GFS forecast lows for next Wednesday. Source: WeatherBell
For us in New England – we’re not expecting to feel much of the chill from this midsummer cool down. Our temperatures should be pretty close to, or slightly below, average. However – being on the eastern flank of this air mass, we’ll have to contend with stormy weather. There’s a pretty solid signal for widespread showers and storms next Monday and Tuesday, perhaps even lingering into Wednesday next week. We’ll have to be on the lookout for heavy rain and maybe some flash flooding concerns. Up until then, enjoy being outdoors without sweating up a storm!