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We can stop whispering about El Niño like it doesn’t know that we know it’s there.
As of June 8, the Climate Prediction Center has declared the official birth of the new “Little Boy,” a rather anticlimactic pronouncement of something that was already fairly obvious.
El Niño is the irregularly recurring warming of a stripe of equatorial Pacific waters, its moniker being Spanish for the “Little Boy,” named for the birth of Jesus as it was often first noticed on the coast of Peru in centuries past near Christmas. La Niña, the “Little Girl,” is the cooling of those same waters (and not named until the 1980s), ongoing for three years prior to early spring, a big culprit in the non-winter we experienced.
· Heat prediction contest takes your entries through Sunday. See last section of column.
In discussing potential effects of El Niño, it is important to draw a distinction between global and local.
There is much intense discussion from climate experts about El Niño inflaming already hot global temperatures for extreme heat waves and, quite likely, a new warmest global average temperature record.
El Niño does indeed inject heat into the atmospheric system, and global temperatures almost always spike when it occurs. Already having year after year of near-record global average temperatures, and this one on track through five months to eclipse those, new record peaks for global average temperature are anticipated with the new El Niño this year as well as possibly in 2024.
But heat is not evenly dispersed in the global atmospheric system, and that is how projections of record global average temperatures and expansive heat waves could all occur as expected and, possibly, not seem like it in our backyards.
The more granular we get with continental or regional weather patterns, there will still be areas that end up under hot high-pressure ridges more often and other areas that land more often under the cooler low-pressure troughs between them.
In fact, there is a general tendency for El Niño-related patterns over North America to park warmer highs over northern latitudes and trap cooler troughs to the south. We’ve seen exactly that in May and early June so far, exemplified by last week’s push of smoke-laden chilly air from Canada that even allowed the formation of some spotty June frost in parts of Southwest Virginia. (See second section of today’s column.)
Increased global average temperatures happen because the “heat dome” highs are generally larger and hotter than they have been in the past, and those offset the cooler temperatures in the troughs when all the numbers get added up. But if your location gets more trough than ridge in a particular season or year, the local average temperature won’t track the same direction, or at least not with the same intensity, as the global average.
There are no hard-set outcomes with El Niño for our region, but there are some loose correlations between previous El Niño episodes and some weather we’ve experienced to give us some idea of what we might expect in the months ahead.
Probably a wet winter
Since 1950, when El Niño Southern Oscillation data became more certifiable, the 1997-98 El Niño winter ranks as the wettest on record at Roanoke, Lynchburg and Danville, and is third wettest at Blacksburg.
Other El Niño winters like 1986-87, 2002-03, 2009-10, 2015-16 and 2017-18 also often show up among the top few wettest winters at several regional locations.
El Niño is strongly correlated with an enhanced subtropical jet stream that typically flows west to east across the southern U.S., especially in the cooler months. This tends to bring wet systems across the southern tier of states that scoop up more moisture from the Gulf of Mexico.
Virginia is often at the edge of the southern U.S. wetter zone in El Niño, with a dry Ohio Valley spot not far west, but most of the Old Dominion tends to tilt wet more often than not in El Niño winters. How much of that wet turns white is a whole other matter discussed a few headers below.
Atlantic hurricanes usually more sparse
The automatic reflex of any tropical meteorologists from years of study is that El Niño in the Pacific tends to increase tropical weather there, while strong winds aloft from the west tend to shear off potential tropical systems in the Atlantic and keep the hurricane season reduced in terms of numbers of named storms and hurricanes.
The extreme warmth across much of the Atlantic has some scientists wondering if this El Niño might be different, and of course, it only takes one extreme storm into a densely populated area to make for a memorably bad hurricane season. Similarly, it would take only one tropical system on a certain inland path to flood our region.
Summers typically not all that hot
Few of the hottest summers that Southwest and Southside Virginia have experienced historically based on seasonal average temperature have occurred during El Niño. 1987 is the most frequent El Niño summer that shows up among the warmest summers in the historic weather records for sites across our region.
Some El Niño summers like 1983 produce short extreme heat waves that go well over 100 degrees for a few days in the lower-elevation parts of our region. But it is not common in an El Niño summer for stagnant, hot high pressure to park over our region for weeks on end.
Big snowstorm potential increases
El Niño, contrary to some fairly widespread belief, does not necessarily produce a cold or snowy winter for our region. But what can be said based on prior trends is that El Niño patterns up the ante substantially for the potential of having at least one large snowstorm in our region during the course of winter.
In the past quarter-century, there have been five snowstorms that have dumped a foot or more of snow on roughly half or more of the Southwest/Southside Virginia region Cardinal News covers. Four of them – January 1998, December 2009, January 2016 and December 2018 — happened during El Niño winters. (February 2014 is the exception here, occurring in a neutral equatorial Pacific pattern that was neither El Niño nor La Niña.)
Widespread foot-plus regional snowstorms in January 1966 (two of them), December 1969 and February 1983 also occurred during El Niño, as did the extremely cold 1976-77 and 1977-78 winters with many small to medium snowfalls.
El Niño patterns often combine a swift and moisture-rich subtropical branch of the jet stream across the southern U.S. with blocking high pressure to the north that can force cold air south. This can result in weeks of repetitive wintry weather (like the 2009-10 winter) or, if the subtropical jet is stronger and often brings in warmer air, can allow for one or two short-window setups amid a mild, rainy winter where enough cold air manages to slip in to turn the thick moisture into snow (like the 2015-16 winter).
Whether the coming winter has a chance to be colder and snowier on the whole might be a little easier to guess by fall, when more is known about the intensity and alignment (centered more east or west?) of El Niño, potential entanglements with other atmospheric patterns, and how early-season snow cover has progressed (or not) across Siberia and Canada.
A JUNE FROST
There is a saying that something that is short-lived “won’t last as long as a June frost.”
There were in fact some patches of June frost to test that saying last week, in Carroll and Floyd County along the Blue Ridge west past Interstate 77 toward the southwest corner of the state, not most places but in some spots, much to the chagrin of a few farmers and gardeners.
Burke’s Garden in Tazewell County dropped to 33 degrees officially on Friday morning, June 9. Copper Hill in Floyd County had lows of 39 and 37 on Thursday and Friday mornings, June 8 and 9, respectively.
Sparta, just across the state line in Alleghany County, North Carolina, came up with a numbing low of 29 on Friday morning.
Most locations in Southwest and Southside Virginia dropped into the 40s both mornings, with a few lower 50s in more urban areas.
The unseasonably cool air was funneled southward by the backside rotation of a strong low near Maine. That same flow from the sluggish low also swept in the dense smoke from Quebec and Ontario forest fires that choked New York City in a gagging smog and grayed out ridgelines in much of Virginia
The “blocked” pattern that stalled that low near the northeast U.S. and southeast Canada for so many days has eased and a more typical west-to-east flow has resumed across our region, angling more northwest-to-southeast at times.
This has helped sweep away most of last week’s smoke, though so long as the fires are still burning in western and eastern Canada, likely until next winter, we’ll get occasional wafts of it at least high in the atmosphere even if it’s not as bad at the surface as last week was.
We are also seeing more typical June temperatures with many locations topping 80 the next several days, and periodic chances of showers. Many areas in our region are getting pretty dry, and there are some indications a more widespread rain may happen in the early to middle part of next week.
LAST CALL FOR HEAT CONTEST ENTRIES
Sunday (June 18) is the last day to enter the Cardinal Weather heat prediction contest. Entries are accepted through midnight.
Email firstname.lastname@example.org with your name, where you live (city, town or county), and your pick for the hottest temperatures between June 20 and Aug. 31 at ONE LOCATION chosen from the 12 towns and cities spread across our region listed below. It’s OK for couples or families to put more than one entry on an email – and no age limit.
Whoever is closest gets a $25 gift card and notoriety in this space for summer forecasting prowess (or a lucky guess — it is truly better to be lucky than good). I will only be giving out one gift card, so the tiebreaker if two entries are equally close will be whose entry I received first.
Below are the 12 locations you can pick from. Last week in this space, linked here, I listed the historic ranges of coolest to hottest peak temperatures as a sort of guide for these locations. This week, to put some of my own skin in the game, I am offering my predictions (otherwise known as somewhat educated guesses) of the hottest temperatures it will get at each location. I am going for a summer without 100-degree temperatures in our region. Feel free to go higher or lower on your pick (which, remember, is only for one of the locations you select, not all 12).
· Abingdon, 93
· Appomattox, 96
· Blacksburg, 90
· Clarksville, 99
· Danville, 97
· Galax, 91
· Lexington, 94
· Lynchburg, 96
· Martinsville, 98
· Roanoke, 97
· Wise, 90
· Wytheville, 90
Journalist Kevin Myatt has been writing about weather for 19 years. His weekly column is sponsored by Oakey’s, a family-run, locally-owned funeral home with locations throughout the Roanoke Valley.