Jan 2, 2012

November 2011

On November 2nd, this surface low produced blizzard conditions in central Colorado:

On November 3rd, freeze warnings were issued in central Texas (light blue):
This 986 mb low produced a 68 mph wind gust at Lamar Colorado on November 5th:
This storm was impressive in water vapor imagery, but also look at that little cut-off low off the East Coast (about 500 miles east of Florida).
That cut-off low was named Tropical storm Sean just three days later. Here is a surface analysis from November 7th at 18Z, just 15 hours before it was named:
There is a cold front extending from the low which is to become Sean, to Puerto Rico. There is also a 946 mb low near Greenland. Water vapor and visible imagery from the same time show how much dry air is surrounding it:
There is also a tornado outbreak beginning in the plains at this time (more on that later). Here is how it looked as it was named Subtropical Storm Sean on November 8th at 9Z (3 AM CST):
RUC analysis charts indicate that although it had a warm core, there is still considerable temperature contrast across the circulation, especially at 700 mb:
By 18Z, it had been named Tropical Storm Sean. Here it is 2 hours after:
Sean passing Bermuda on November 11th:
Meanwhile, there was a small tornado outbreak on November 7th in southwestern Oklahoma. Notice the mid 60s dewpoints and winds backed to southeasterly particularly around Frederick:
This coincided with an area of 3,000+ CAPE:
The result can be seen on the Frederick radar at 2151Z (3:51 PM CST):
The mesocyclone is easier to see on the 1.3° elevation scan. Same supercell 13 minutes later:
RUC analysis charts show backed surface winds, a veered 35+ knot low level jet, and strong divergence at 250 mb over southwest Oklahoma:
The sounding from Oklahoma City has 0-3km SRH at 364, and 1km still at 320:
There were additional tornadic supercells the next day including this one near Houston:
On November 8th, a 943 mb storm in the Bering Sea hit nearby buoy 46035 with nearly 40 foot waves and 72 knot winds:
By November 9th, accumulating snow had fallen in Wisconsin and Iowa:
On November 11th, freeze warnings were in effect for most of the Florida Panhandle:
On November 25th, a storm reached 940 mb north of the British Isles:
On November 27th, freeze warnings (light blue) were issued for most of the Texas Gulf Coast:
On November 28th, accumulating snow fell as far south as northern Mississippi, including Memphis: