Friday, 14 March 2014

Global Warming and a Mangled Jet Stream

Germany Breaks All-Time Record Highs for Early March, Aswan Egypt Experiences First Rainfall Since 2012

(Germany’s March 9 heat wave set off 22 all-time high temperature records — shown in star pattern outlines. Temperatures shown are in degrees Celsius. Image source: WetterOnline.)

13 March, 214
According to reports from WeatherUnderground and WetterOnline, Germany experienced some of its hottest ever recorded temperatures for early March last week.
A large region including a swath of cities stretching from the northern coastline into the heartland and on toward the French border all saw records — some of which had lasted since the 1890s — fall. The heat pulse was enough to push readings into the upper 50s, 60s, and even the low 70s (F) for some regions. A set of highs extraordinary for a Germany that typically sees daytime temperatures ranging from near freezing to the low 40s this time of year.
Such a surge of warm air was enough to shatter more than 20 long-standing records by as much as 5.9 degrees (F). An unprecedented outbreak of March heat which set trees to blooming and spurred Germans on toward local waterfronts.
Some of the official new records for early March included:
Munster 22.4°C (72.3°F) former record 19.1°C (66.4°F)
Koln/Bonn 21.1°C (70.0°F) former record 19.8°C (67.6°F)
Dusseldorf 20.9°C (69.6°F) former record 20.2°C (68.4°F)
Aachen 20.8°C (69.4°F) former record 20.2°C (68.4°F) POR back to 1891
Hannover 20.2°C (68.4°F) former record 18.4°C (65.1°F)
Hamburg 20.0°C (68.0°F) former record 17.6°C (63.7°F) POR back to 1891
Bremen 19.5°C (67.1°F) former record 18.2°C (64.8°F) POR back to 1890
Kiel 19.3°C (66.7°F) former record 16.7°C (62.1F)
Bremerhaven 18.7°C (65.7°F) former record 16.5°C (61.7°F)
Helgoland 10.6°C (51.1°F) former record 10.5°C (50.9°F)

Mangled Jet Stream, German Heat, Egyptian Storms
Much of Central, Southern and Eastern Europe has been under the influence of a persistent high amplitude Jet Stream wave pattern throughout late winter. This pattern has consistently dredged warmer air up from North Africa and the Mediterranean and flung it over Spain, France, Germany, Switzerland, Austria, the Balkans, Poland and Ukraine. The result has been much warmer than normal conditions for this region.
On Sunday, the pattern amplified pushing a center of much warmer than normal air directly over Germany — setting off new record high temperatures for early March. It is a Jet Stream pattern that remains in place today and one that may amplify with the heat of summer putting Central and Eastern Europe and Western Russia under the guy potential droughts, heatwaves and fires come summer time. A set of conditions that may further exacerbate already strained global food markets, economic and political tensions.

(High amplitude Rossby type wave pattern brings record heat to Germany, record rains to Aswan Egypt. Image source: The University of Washington.)
Returning to early March conditions, the front side of this high amplitude wave pushed a deep trough down through Eastern Ukraine and Russia formed a cut-off low over Greece and accelerated the Jet Stream flow to the south. The result was a high amount of atmospheric instability in a rather unusual place.
Moisture flooding in off the Mediterranean flooded into the storm flow that was now centering over one of the driest places on Earth — northern Egypt. By March 9-10, the pattern had erupted into a series of freak thunderstorms that belched thunder, lightning, hail and record rainfall over this typically parched section of Egypt. In total, Luxor, the city of the famed Valley of the Kings, received nearly 1.2 inches of rainfall. This is nearly 30 times the average yearly rainfall for this desert land, which it received in just one day.
Nearby, Aswan received a stunning .6 inches of rainfall, the first rains seen for this region since 2012 and also a new record.
Events Sunday in both Egypt and Germany are not without their broader context in a world shoved toward increasingly severe weather by human-caused climate change. This year, the world over is experiencing a string of highly anomalous storms, heatwaves, droughts, cold snaps and floods. An ongoing occurrence that for some regions has resulted in a 500% amplification of climate extremes.
Unfortunately, with El Nino about to give its dark gift of ocean warming back to the atmosphere and with ice sheets in both hemispheres just starting their cycles of catastrophic melt, the increased intensity of weather and climate anomaly has only just initiated.
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Hat Tip to Colorado Bob!

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