How far south could an arctic front travel? (climate, snowfalls, hottest)
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I'm wondering how far south an Arctic front could travel into the tropics if the following set up occured:
1. The most powerful arctic front in recorded history happened with extremely cold air at its point of origin - say -80F (-62C)
2. The jet stream was configured in such a way that it had a trajectory direct from its source where it travelled directly in a straight line completely unimpeded by any mountains, bodies of water or other obstacles almost to the equator
3. I know it's snowed in Tampico, Mexico and Guangzhou, China before but could it be possible to travel even closer to the equator than that?
In this thread an event in July 1975 in South America was discussed, where even Cruzeiro do Sul, Brazil at 8S received a pretty potent cool shot (mornings dropped from 59F to 44F). Record lows were set at Iauarete, which was slightly north of the equator. So arctic fronts can go deep into the tropics and even cross the equator under the right conditions - this arctic front came from the Southern Hemisphere, and I don't think a similar event has ever been recorded in the Northern Hemisphere, perhaps because a straight-south trajectory in the Northern Hemisphere is impeded by several seas, whereas South America is all land straight to the equator.
An ideal trajectory would be extremely potent and settled-in Canadian (and perhaps Siberian) arctic air screaming down the High Plains into Mexico and Central America. Judging by historical experience, under the ideal conditions set forth by the OP the arctic air would easily reach the Yucatan and probably down into Nicaragua and perhaps some of Costa Rica (10N), after it crosses one mountain range. I'm not sure if significant cold could make it past two or three mountain ranges, though, but I think the odds would be against any cold making it past the Darien Gap (7N) even if there were ideal conditions.
If there was flat land where the Gulf of Mexico and Caribbean Sea are today, and there were no major mountains between it and the equator, I think the OP's ideal arctic front could easily make it to the equator, considering that South American arctic fronts cross the equator once every generation or so, even with the disadvantage of Antarctic air having to travel over a big ocean. I would even speculate that the arctic air would exert a significant effect down to 10S or even 15S before it dissipated.
As for snow, with current topography and climatic averages I think that if fronts similar to the OP's description occurred (which they probably do on extremely rare occasions) and conditions were conducive for low latitude snow, there's no reason Veracruz couldn't get snow, and given the averages I think Tabasco may be able to have snow as well, and maybe some of the higher towns in Guatemala. I think it would be virtually impossible for any place lower than 15S to get snow in a "normal" low-latitude snow setup (arctic front comes in followed by moisture), i.e. not a high-altitude rainy season sort of scenario. South of there the OP's arctic front wouldn't even produce temperatures cold enough for snow, and even if it did the dynamics would be far too stable, in the same way it usually doesn't snow when an American city sets an all-time record low.
Anything could happen, though, since snowflakes do occasionally precipitate out of a clear sky and at temperatures around 40F, but flakeage of this type is never significant enough to produce a good scene of snow falling, let alone sticking onto anything (the little flakes can stick if the ground is frozen, but this is the tropics we're talking about).
In this thread an event in July 1975 in South America was discussed, where even Cruzeiro do Sul, Brazil at 8S received a pretty potent cool shot (mornings dropped from 59F to 44F). Record lows were set at Iauarete, which was slightly north of the equator. So arctic fronts can go deep into the tropics and even cross the equator under the right conditions
That is pretty amazing. Looking at towns straddling the equator in the Northern Hemisphere (within 2-3 degrees N) in South America and West Africa, one finds that the DJF averages are generally warmer than the JJA averages. I wonder if this is the reason for it.
But when you think about it, it makes sense. Antarctica is a much more potent source of cold air than the Arctic, so one would expect Antarctic cold fronts to have more penetrating power.
In addition, during July, the overhead sun (and the hottest weather) is just south of the Tropic of Cancer rather than near the equator.
Last edited by arctic_gardener; 12-26-2013 at 06:48 AM..
I have heard Siberian cold fronts dip down as far south as Amritsar, India. It can get below freezing in winter (and often does every year). Snowfall is a possibility down there as well, but rarely happens:
I have heard Siberian cold fronts dip down as far south as Amritsar, India. It can get below freezing in winter (and often does every year). Snowfall is a possibility down there as well, but rarely happens:
Keep in mind that none of the residents living in Amritsar have heating facilities.
August - December record highs there are Bull Crap.
I don't think there's a climate in the world where the average high for a month is 94 F and it's never reached 100 F during that month. That said, you are referencing record lows, which look believable year round.
I don't think true Siberian air gets over the Himalayas; although it can reach the south coast of China it's blocked from most of India. They do get cold nights there simply because there's so little cloud in the winter, the days warm up to 20C or more which wouldn't be possible if deep cold air was in place.
Similarly in Europe although Siberian or Arctic air can easily reach the Atlantic coast (and, conversely, mild Atlantic air can get as far east as the Urals) it hardly ever crosses the Mediterranean and penetrates into Africa. Occasionally it can still be cold enough to snow in Algiers or Tunis, but 30N is about the limit. In the Middle East it gets a bit further, with snow having been recorded in Riyadh and quite common in places like Jerusalem.
Really? Do you have a link for this? I know that hail is often mistakenly referred to as snow over there, and it has snowed in the higher elevations of northwestern Saudi Arabia, but Riyadh??
Really? Do you have a link for this? I know that hail is often mistakenly referred to as snow over there, and it has snowed in the higher elevations of northwestern Saudi Arabia, but Riyadh??
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