>North Africa/Europe Scorcher, North America Summer Pattern SeeSaw

Today across southwest and south-central Europe under the high.

A major heat wave is blistering western Europe with a 599dm broiler-plate ridge park directly over the Sahara Desert of North Africa which underneath is boosting Algeria’s surface temperatures to 120F/49C but the main part of this story isn’t the Saharan heat as this is fairly typical for this time of year, it’s the interaction in air flow around this high and the trough over the UK and northeast Atlantic. The trough and high is funneling hot, dry winds out of Africa, across the Med and into Spain and France where 100 degrees is being felt from around Madrid to near Paris where mid-90s has made for blistering, uncomfortable conditions over the past few days. The hot winds are blowing out of the southwest and ahead of a cold front associated with a strong low just north of Scotland. We here in Scotland have seen little sun for nearly a week and persistent and heavy rainfall and chilly winds. Certainly well below normal temperaturewise here, but thanks to our weather, this is forcing the African high to buldge and heat up France and other western Europe inland area that are more often similar to London’s temperatures and not southern Spain.

Cooling relief is on the way as the low and it’s cold front is sweeping east and will cool things off for Spain and France. High’s today will take a run at between 95-104 in interior Spain and the Madrid area, whilst Paris and interior France will take a run at 95-100 degrees.

Whilst the persistency of a deep trough stands it’s ground across the the United Kingdom where low pressures systems have raced in and cycled around the northern periphery of the North African/Mediterreanean High, areas of western Europe such as Holland, Germany, Denmark, Poland and Scandinavia have generally been under negative heights and most the the heat and sunshine associated with the semi-permanent summer high has been more over Africa and the Mediterreanean and counties surrounding it. With a zonal jet stream, much of interior northern or northwestern Europe haven’t seen any major heat, if so, it’s been short lived as Atlantic low pressure has been the dominant feature for the past month and a half. This is in stark contrast to May and June when the pattern was the opposite. We here in Scotland, England, Ireland and Wales enjoyed a northward migration of the Azores high, pumping sub-tropical air up over us, whilst an unseasonably cool, unsettled regime took control of central Europe. Areas than hardly ever see rain, saw it in places like Greece and Italy with a trough that dropped south in reaction to the high building over the northeast Atlantic and UK.

If you draw a line from A Coruna to Amsterdam across to Berlin to Warsaw, thats the seperation between positive and negative height anomolies in the means the past month, these heights of course have flexed north and south as passing low’s crease and wrinkle the African/Mediterranean high and currently the deepening of the trough over the northeast Atlantic has pumped the ridge further north, forcing heat north, northeast.

The Great Lakes to East Coast expereinced cooler, wetter than normal conditions with regular passing of low pressure, keeping temps down. Canadian high pressure settled in between low’s that normally would move across central Canada, dropped into a deep trough over the Eastern US and forced unusually cool air that’s normally over Hudson Bay into New England and what’s normally over the Arctic into Ontario and Quebec. Meanwhile hot weather normally associated with the Western Plateau was forced into the heart of British Columbia and at times the Yukon and Northwest Territoies where highs topped a remarkable 80 to 91 degrees. Tuktoyaktuk on the Arctic Coast hit a hot 81 degrees. The entire balance of heat went topsy turvy as if one place experiences intense heat in an area not normally seen, the entire system needs to rebalnce and make up for the forcing somewhere else. Basically Desert Southwest heat spread into the Pacific Northwest. 103 in Seattle, 110s east of the Cascades and what’s normal for the Pacific Northwest was in and around the Arctic Circle. This was at the same time Arctic air drove south from Baffin Bay. High’s on the Hudson Bay coast of Ontario only topped the upper 30s to low 40s and areas of southern Ontario, Quebec into the northeastern US near the Canada border only saw high’s make the 40s and 50s.

August came and a readjustment in the locked pattern came. Major troughs dropped into the West, Las Vegas went from the 105-110s down to 90s and even 80s for highs, whilst the Midwest heated up and finally all this heat that has roasted the southern plains unabated since May was forced into the Eastern third. New York to Boston finally have heated up as well as experiencing a southerly flow out of the Caribbean and Gulf, bringing true summertime heat and humidity which will remove some of those chilling memories from early summer 2009. The pattern now brings trough-ridge cycles across the country as summer nears it’s end. A recent heat wave roasted an area from Virginia to southern Quebec where 90-degree air and 70-degree dew points made for more uncomfortable the further north you go, especially those that have endured both a very cool, dreary summer and lack of AC. A good example is an area from Montreal, QC to Moncton, NB which saw 85-92 degree air and tropical dew points that made it feel like 100-105 degrees where it has seen most days this summer only make the 60s to low and mid-70s, rainy days and some nights that dropped near to freezing, suddenly saw cloudless skies and sweltering heat and nights that remained clear and starry but very sticky and air that stayed in the 70s!! In Quebec?? For 70-degree nights in Montreal and southern Quebec you need a northward Bermuda high to send a moist, tropical low in as well as hot, steamy days, for it’s the humid air and daytime heat that keeps nights so warm in places you’d expect to cool off nicely at night. Not always and even during cool, wet summers, you can and do get periods of unusal heat and humidity. After a slower, lock down pattern between two very distinctly differing air mass and origins, the pattern through August has been more of a progressive one and therefore has allowed real heat and humidity into the Northeastern US and southeast Canada as the month wears on. See how cool pools get colder as we approach September over the Northern Rockies to Upper Midwest. 8 inches of snow accummulated and was still coming down in the Bill Horn Mountains of Wyoming according to this video recorded Sat, August 15th, note they mention, how it was hot and sunny the previous day, this is a reminder that summer’s pattern is more progressive as the seasonal adjustments begin within the atmoshere and this relays down to the surface http://www.weather.com/multimedia/videoplayer.html?from=email&bcpid=823425597&bclid=877032950&bctid=34591956001. Back in July snow was reported in Colorado’s High Country. Never before have I heard of July snowfall in the past 8-10 years and my tracking of US weather.

Coming soon.. Extreme and rare weather events for Central Park and Minneapolis, I shall discuss these events later.

Thanks for reading.

-Mark