Thursday, February 2, 2012

Romanian Dumpage

With another disappointing storm behind us (3" at Alta) and at least 7–10 days of mainly dry weather ahead of us, it is time to start looking elsewhere for our powder fix.

How about Bucharest, Romania?  Eastern Europe is in the grips of a cold wave and Bucharest got pounded with snow last week.  I was blown away by the photo below, which was taken last Friday and posted on cnn.com.

Source: cnn.com/AFP/Getty Images
Bucharest lies in eastern Romania between the Carpathian Mountains, which form a hook in central Romania, and the Black Sea.

Source: Google Maps
The Carpatians are 1200–2000 m high, with some higher peaks in the area northwest of Bucharest.  Not a huge range, but, like the Appalachians, sufficiently high to block cold air at low levels under the right conditions.

This appears to have happened late last week.  As shown in the 0000 UTC 28 Jan GFS analysis below,  cold air from the Ukraine and interior Eurasia channeled southward and then westward around the Carpathians.

1000 mb wind and temperature at 0000 UTC 28 Jan 2012.
Color scale changes every 2ÂșC (sorry about the lack of a scale).
Click to enlarge
This appears to be quite similar to the cold-air damming that occurs east of the Appalachians.  In addition, a pronounced coastal front developed along the west coast of the Black Sea and likely served as a locus for heavy precipitation (note the temperature contrast).  Similar coastal fronts often form along the northeast and mid-atlantic coast of the United States in response to cold-air damming and contrasts in surface sensible heat fluxes between the land and ocean.

Further digging is needed to determine the role of these orographic and coastal processes on the Bucharest storm, but it sure looks like an interesting case.

1 comment:

  1. My curiosity got the best of me, I had to look back at the GFS loop (got to the archive by editing the URL on the U of U GFS page). It looks like a deep closed low developed to their south, centered near Greece, and wrapped a bunch of moisture back across Romania in easterly flow, lifting it over the low-level cold tongue. Some of this moisture probably came off the Black Sea but judging by the wind fields I think that the majority of it was from the much larger and warmer Mediterranean.

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