We shall see
. . . . But Check this out
By Mark Vogan -
Have we seen a cool summer across the US and Northern Hemisphere in 2008?
THE STRONG LA NINA DOMINO EFFECT
It doesn’t seem that long ago that we were revising the winter stats and looking towards the warm season. Now, we’re into August and we’re now on the precipice of a large scale cool down, starting at the pole and a progression southward as we enter fall and daylight shortens, a downward trend towards our Northern Hemisphere winter is beginning, yes even in August and, yes even as places are still sweltering far to the south of the tundra and permafrost territories. We have arrived at a time when the sun grows ever lower and Arctic high pressure cells strengthen and jet streams speed up as the “cold switch“ gets turned on. The first snow flakes will soon begin to fly and are likely already doing so in the Arctic. Once snows stick and the ground turns white, temperatures soon drop.
NORTH POLE’S COLD WINTER AND LAG IN SUMMER WARMING EFFECTING AREAS THAT TYPICALLY ARE HOT
What’s very interesting is, that when I mention that even though winter is beginning over the North Pole and daylight is down some 3 hours from June 21, and places to the south are still sweltering, like Atlanta‘s 90s or Dallas, Phoenix and Las Vegas 100s. Places such as New York City, Chicago, even Winnipeg, Montreal could and perhaps should still be feeling the heat of the summer sun at this point in August. However they’re not and haven’t done throughout much of summer. The only real reason why New York has averaged slightly above normal and remained warm and sticky is mainly down to abnormally warm waters off the East Coast, adding heat and humidity to the atmosphere. But real hot days haven’t been the case and the reasons are explained below. Take Chicago as a representation of the Midwest/eastern plains where real heat has been void. This in my opinion is a direct result to last winter’s pattern which has fed into this summer. The coldest departures from normal last winter has turned out to be the coolest areas this summer. Those wet soils that developed from last winter’s record snows, received record or near record spring rains, forcing cool pools and training-thunderstorm corridor for summer and I would strongly expect a cool pool for certainly this fast approaching fall over this same area. The pattern right now was cast and can be traced back to last winter. Chicago has had a cool wet summer (even though it’s averaged above normal in the means) as we haven’t seen truly HOT days. The warmest has been a somewhat pathetic 91 degrees, nothing to write home about and a far cry to O‘Hare‘s 102 in July, 2005 and 99 on two days in 2006. Even night time low’s haven’t been particularly oppressive, with mostly comfortable 60s, rather than 70s and even 80s, this is thanks to an unusually persistent northwest flow of dry, Canadian air which has allowed a summer-type radiational cooling to take effect, dropping off temps at night with the dry air which can‘t contain heat the same as humid air.
Those early wet soils forces instability by pumping water vapour into the atmosphere and as daytime heating stirs the atmosphere and forces it to rise into the colder regions of the upper-atmosphere of the Midwest and eastern plains, development and redevelopment of strong thunderstorms over the same area occurs. As these recurring thunderstorms fires up in the heating of the day and falls apart as the air cools at night, this keeps the strong solar rays from really heating up the Midwest atmosphere as blocks an eastward migration of intense Desert Southwest heat. Usually when the Midwest heats up, so too does the mid and upper levels of the atmosphere, reducing the lapse rate of difference in temperature with height, therefore capping and suppressing the ability for the atmosphere to produce thunderstorms. High soil moisture from the big 07-08 winter snows set the stage for a continued wet pattern. A La Nina atmospheric setup joined forces with a springtime feedback which continued the wet pattern over the same area that was very snowy last winter and when you keep those soils wet in the right place and it isn’t hard to continue a stubborn monotonous cycle into the future. Basically the same ingredients readapt the the chance in the seasonal atmospheric fluctuations and the cycle continues unabated.
In a nut shell
A STRONG LA NINA RIDGE-TROUGH PATTERN+MOISTURE LADEN SUB TROPICAL JET, FEEDS RECORD SEASONAL SNOWS ACROSS THE WEST, MIDWEST AND NEW ENGLAND. THEN COMES SPRING, THROW IN SOME DAYTIME HEATING, PLACE YOUR HIGH’S TO THE WEST AND TO THE EAST AND HAVE A LINGERING COLD POOL OVER THE NORTHWEST AND BANG, THUNDERSTORMS DEVELOP IN THE SAME AREAS THE RECORD SNOWS WERE FROM WINTER. GET INTO SUMMER AND THOSE SATURATED SOILS KEEP THE AIR ABOVE MOIST AND THAT STRONG SOLAR ENERGY COOKS THIS ENERGY, FORCES IT TO RISE AND BINGO. THUNDERSTORMS FORM. INCIDENTLY, WEST AND EAST OF THE CORRIDOR OF RAIN, DROUGHT CONDITIONS PREVAIL AND STRONGER-THAN-NORMAL HEIGHTS ARE ACHIEVED, THEREFORE CAN LEAD TO A MORE AMPLIFIED WIND CIRCULATION INTO THE THUNDERSTORM CORRIDOR OF THE HEARTLAND.
The winter of high precipitation levels and a hot, summer environment and upper low and troughing forced by wet soils below has supported powerful heartland “Mesoscale Convective Complexes” with the correct confliction of ingredients that originated from winter. This type of pattern didn‘t allow nationwide heat waves this past summer like in 2006. However drought or dry conditions are/were present over the Great Basin and western and southern plains as well as the Southeast (focus on Carolinas) and record highs have been achieved (111 degrees in Nebraska, 109 in Kansas and Oklahoma and 114 in Texas. 109 in South Carolina). The few heat waves that did occur (early summer) in the Northeast was home brewed and not from the typical Southwest origins because of the Midwest heat-breaker. The extremely dry Carolinas fed to stronger heights over the Southeast and this coupled with a stationary frontal boundary to pump and excellerate hot southern air into the Northeast which produced a high of 100 degrees in New Jersey, 99 degrees in both Newark and LaGuardia and low 100s over Virginia.
AVERAGE SUMMER IN WEST, BUT VOID OF EXTREME HEAT, ALTERING RECENT TRENDS?
For example, in 2006 Phoenix baked to 118 degrees. This years hottest has been 115 degrees. OK, that’s not that cool and still some 9 degrees above normal. Las Vegas last year (2007) hit 116 degrees and in 2005 matched their hottest ever temperature of 117 degrees. This years hottest was 111 degrees. Death Valley’s hottest (nationally hottest) this year was the coolest since 2004 when the highest temperature achieved was 125 degrees. This year’s peak was 127 degrees, but as hot as this is, it’s down from 2005, 2006 and 2007’s peak. Last year was 129 degrees. The difference in these numbers might appear too small to even pay attention to but when you look at Death Valley’s typical summer maximums and more importantly the last 4 to 6 years, it’s basically the coolest national summer maximum achieved since (another nationally cool summer) of 2004.
It’s not the coolest summer but for extreme heat, this I believe has been a cooler summer than recent years and I believe it’s a direct result and lingering effect from the strong winter La Nina.
So, where’s been cool this summer? Alaska, the Northern Plains/Midwest, the United Kingdom?
WHAT A DIFFERENCE A YEAR MAKES: ALASKA’S COLD WINTER, COLD SUMMER
Alaska has received a very wet, cloudy and cooler than normal summer with reports during July of snowfall and not at particularly high elevations. Some areas of Canada have also been cool. Vancouver and British Columbia as well as much of the Prairies have been slightly cooler than normal and void of any extreme heat. When last August we saw record heat expand over the American West with 111 degrees recorded at Glendive, Mt and 3 days of 110 degrees at Miles City, Mt, we saw unofficial temperature reports out of Rockglen, Saskatchewan where the weather station thermometer struck 115 degrees. This, if official would break Canada’s maximum temperature ever recorded. Barrow on Alaska’s northern shores even warmed to the 70s last year and interior areas boasted 80 degree warmth. This year it’s had many days only in the 40s and nights close to freezing.
LAST SUMMER
Remember back to August of last year across the lower 48. We had a scorching August from the Southeast where the core of heat was found (numerous 100s for Atlanta, Montgomery, Charlotte etc), even New Orleans along the Gulf Coast saw a few 100 degree days, normally this area heats to the low to mid-90s but is controlled by it’s high dew points which act as a thermostat.
The Ohio Valley received a remarkably warm August, September and even October period and Chicago’s marathon was tainted by an air temperature over 90 degrees and I believe there was at least one who died from the unprecedented October heat.
THIS SUMMER
This summer sure hasn’t displayed that type of heat across the lower 48 and across central Canada where a cool northwest flow pulls refreshing, almost chilly air in from the Arctic and this dip in the jet over the heart of North America is more like a fall pattern. Last winter produced temperatures as low as -40 across the prairies of Canada. With -60s in the Northwest Territories and -72 in Alaska, exactly where it was cold last winter, it was colder than normal throughout this summer with below normal heights over the Northern plains and Great Lakes. With a neutral ENSO or even a return to a weak La Nina, I believe the already cooler upper atmosphere over these areas now for nearly a year will have a return to the coldest air masses IF WE SEE A NUETRAL OR LA NINA WINTER.
IF THE ENSO PLAYS OUT, LAST WINTER WILL HAVE SET THE STAGE FOR THIS COMING WINTER AND AS FAR AS THIS SUMMER GOES, WELL ITS MAINTAINED WHAT LA NINA STARTED IN THE MIDDLE OF LAST WINTER. A TRUE TESTAMONEY TO A STRONG LA NINA.
GREENLAND COLD STORAGE
Even across Greenland where we saw record or near record cold last winter over the heart of the vast ice shelf, Summit Camp supposedly plummeted on at least 1 (probably more night’s) to -86 degrees and over recent days or weeks we have seen cooler than normal temperatures with a -20C reported just recently. Yes Greenland is no hot spot for sunbathers but for August I believe -20C is a little colder than what is typical.
MIDDLE AUGUST PATTERN SHAPING THINGS TO COME?
When we look at the overall upper pattern over North America and Greenland. Cold temperatures are really cranking up across the vast frozen wastes. We look at Canada’s northern territories and why is the jet amplified and dropping much cooler air than typically seen for this time of year into the heart of the eastern half of the United States. Dew points down as far as the Gulf states are remarkably low. Temperatures are way down from what it was at this time last year from Chicago to Memphis and with a monster dry air mass that originated over Canada in place and effecting most of the US from the plains - east, daytime temperatures are only warming to the 70s and low 80s from the Great Lakes to Southeast and nights are cool because of the dry air, 50s for Chicago, low 60s for Atlanta, In August? Ironically Atlanta received it‘s warmest night on record around this point in August last year, the low was 82. Unusually powerful upper lows are spinning off this northwest flow out of Canada and they are strong because the contrast between warmth and cool is greater. All this indicates to me, that we are seeing cooler than normal conditions over northern Canada and it’s beginning to further cool, normal for this time of year BUT MORE SO THAN NORMAL. For a Canadian high to penetrate so deep into the heart of the USA and for mid-August is remarkable and this tells me that things are changing not only across the northern regions but in the upper atmosphere, we shall see more heat in these mild regions but a quick and early start to winter could be upon us.
BLOCKBUSTER US/CANADA WINTER 2008-09?
Because of the lingering cool pool over the heart of the North American continent, stretching from Alaska, Nunavut, Hudson Bay down through the central Plains and Midwest, a by-product to last winter, I believe because of just the INTENSITY OF THE LA NINA and the reluctant warming of the eastern Equatorial Pacific, this La Nina casted atmosphere is becoming the groundwork laid through this summer to what we may be looking at this upcoming winter season. The faded La Nina and turn to neutral has allowed cool pools to exist throughout the 2008 summer and because of strong potential of a neutral or return to La Nina means that even last winter, will impact the upcoming winter and this may lead to last winter being a harbinger of what could be an even colder US and North America winter to come. Perhaps last winter only being a tease. This is merely personal speculation and I could be very wrong but many many things that point to global warming is struggling to keep heads above water. Countless articles published in the 20s and 30s that cried a warming global climatic disaster are surfacing and although these patterns in play now are by no means a definitive message of things to come in terms of global cooling we can look back at history and see that we have been here before when we measure up our current climatic pattern and realise the cooling that returned after a similar warm episode back in the 1930s and 40s. We will see warming again when the next El Nino turns up.
However as we continue a downward trend in solar activity and a transition to a cold PDO. Last winter’s La Nina could hold a significant key to what could be a major flip in the global climate system and flip to colder temperatures.
The term I have dubbed “The La Nina Domino Effect” can occur and I believe is occurring presently is only possible when the PDO turns negative and La Nina’s are more prevalent. El Nino’s of course can and do occur during cold PDO episodes but produce less El Nino and more La Nina’s. The El Nino that do occur don’t become strong.
The overall Equatorial Pacific cold-temperature feedback to ridge-trough positions have allowed a distinct pooling of cold air over key regions of the world for the past 8 to 10 months that cry out cold, cold, cold this coming winter if things remain as forecast.
APPROACHING RAMP-UP TO EAST COAST HURRICANE LANDFALLS, MAY SET THE STAGE TO COLDER THAN NORMAL NORTHEAST, MID-ATLANTIC WINTER
The past two winters across the Northeast and Mid-Atlantic have been warm and fairly snowless (except New England). Last winters warmth was directly linked to La Nina because La Nina although produced a colder US winter overall, does position a high over the southern states and up the east coast, keeping the storm track off to the west and north. The by-product to such a pattern and frequent mild air flows from the south, meant waters off the coast warmed significantly under high pressure. This allowed the summer to be warmer and muggier.
The question is how could we see a cold winter again back in the Northeast when waters are so warm offshore?
My theory to this ties into the Atlantic basin tropical activity. Couple the forecast for this season and where we expect storms to come into and the time of year. Hurricanes remove heat from the ocean, if we get a couple of hurricanes either into the Carolinas or even more so, up the east coast and in the late season when things are beginning to cool off, we could strip some of this water from the coast, meaning when Arctic air masses do drop down from Canada, the waters wouldn’t feed back to the atmosphere and moderate this cold air mass. If waters were warm, New York may only chill into the teens, but if waters are colder, the cool waters will cool the air above and not warm it. This would indicate that if these two elements play together, we could see some very cold air that would weaken minimally and could produce the coldest temperatures since January 2004.
