Mar 17, 2011

Snow, Thunderstorms, and Tsunami

On February 27th, a deep trough was located over the southwestern US:
Winter storm warnings (pink) were issued down to the Mexican border in Arizona, and freeze warnings (blue) for the San Francisco area:
The coldest temperatures in San Francisco were on the morning of the 26th:

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1030 AM PST SAT FEB 26 2011


THE FOLLOWING SITES SET A NEW RECORD
LOW TEMPERATURE FOR THIS DATE

LOW PREVIOUS YEAR OF
SITE TEMPERATURE RECORD PREVIOUS RECORD

NAPA 27 30 1945
OAKLAND 34 38 1987
OAKLAND INTL ARPT 32 34 1962
SFO INTL ARPT 35 36 1971
SAN RAFAEL 28 32 1996

THE FOLLOWING SITES TIED PREVIOUS RECORD LOW TEMPERATURES

LOW YEAR OF
SITE TEMPERATURE PREVIOUS RECORD

SAN FRANCISCO 37 1962
MOUNTAIN VIEW 34 1962
SAN JOSE 33 1897

The San Francisco area had snow on the 25th for the first time in 35 years. The Los Angeles area had unusual snow (graupel?) as well. see pictures here.

This system produced a significant severe thunderstorm outbreak:
On the 27th, these supercells in Missouri were moving over areas that had been snow covered the previous day:

On March 7th, a snowstorm hit Burlington, VT with 25.8", the 3rd largest ever. Burlington now has 124.3" on the season, the 3rd snowiest on record.

On the morning March 9th, thunderstorms rapidly developed on a cold front moving through Louisiana and Mississippi:
Radar from Slidell shows a strong bow echo forming along the Gulf Coast:
The bow as it went through Mobile:
Base velocity reveals how intense the inflow ahead of the bowing segment is:
Numerous tornadoes were embedded within the bowing line:
On March 11th, a storm was producing major flooding for the Northeast and Mid-Atlantic, while another hit North Dakota with blizzard conditions, where 800 people were stranded.
Here is a plot of the water column height from a buoy near the location of the 9.0 earthquake on March 11th:
The smooth curves are the normal twice daily tides, and the abrupt disturbance around 6 GMT is the tsunami.

The North Atlantic continues to have very heavy storms late into the season. This 952 mb storm was from March 14th:
This storm prompted winter storm warnings for central Missouri:
The areas which were hit hardest by the tsunami in Japan are experiencing cold and snowy conditions.
The jet stream coming off Japan is over 200 knots:
The 936 mb storm which this produced is a far greater threat to vessels than the damaged nuclear plant in Japan noted on this chart:
A 936 mb storm is equivalent to a category 4 hurricane.

It has been reported that Moscow has been having its coldest winter in 100 years.

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