UK Storms and Climate Change

On Christmas Eve, a storm with a central pressure of 929 millibars hit the UK:

For comparison, Hurricane Sandy had a minimum central pressure of 940 mb. An eye was visible in satellite imagery (top center of image):

Just two days later the UK was hit by a storm of 943 mb:

Yesterday, a 948 mb storm was near the Kamchatka Peninsula:

Some have said that the storms affecting the UK are related to "climate change". "Climate change" really just means enhanced greenhouse effect. Increasing greenhouse concentrations would produce the most warming where the greenhouse effect is weakest because that is where infrared transparency is greatest and where there is the most infrared escaping into space that could potentially be absorbed. This tends to be cold polar regions because cold air can contain only very limited amounts of water vapor, the dominant greenhouse gas. Since enhancing the greenhouse effect warms cold areas faster, the temperature contrast is reduced. Extratropical storms such as the one that recently hit the UK are caused primarily by a strong temperature contrast. So "climate change" should reduce the intensity of extratropical storms. Hurricanes on the other hand, are powered primarily by the release of latent heat, not by temperature contrasts.

Late December Winter Storm

From December 21-23, this storm produced 15.5" of snow at Larned, KS, 25.2 " of snow at Ashland, WI, 1.25" of freezing rain in New York (Canton, Potsdam, Rensselaer Falls), and 10.24" of rain at Williams, IN:

Tornadoes and widespread wind damage occurred on December 21st:

3 fatalities were reported. One from an EF-2 in Arkansas, another from an EF-2 in Mississippi, and one from wind in Mississippi. All three were in mobile homes.

Last night, temperatures as cold as -20 occurred as far south as Dubuque, Iowa.

Chicago Area Cold

Temperatures went below zero across most of the Chicago area this morning:

OFFICIAL AND SUPPLEMENTARY NWS OBSERVATION SITES
------------------------------------------------
AURORA/SUGAR GROVE:  -13
ROCHELLE:            -13
DUPAGE AIRPORT:      -10
ROCKFORD AIRPORT:     -9
WAUKEGAN AIRPORT:     -7
CHICAGO-O`HARE:       -6
JOLIET:               -5
KANKAKEE:             -5
LANSING:              -5
NWS ROMEOVILLE:       -4
WHEELING/CHI EXEC:    -4
VALPARAISO IN:        -3
PONTIAC:              -2
PERU:                 -1
CHICAGO-MIDWAY:        1
RENSSELAER:            1
CHICAGO-NORTHERLY ISL: 3

The -6 at O'Hare Airport was the coldest this early in December since 1978. The -6 was surprising because NAM MOS had been predicting 4 yesterday.

In Australia, significant snow fell on December 5th in New South Wales.

Early December Snow Cover

Today, snow already covers 66.9% of the Contiguous US:

With snowpack temperatures well below freezing even in Texas, the snow may be slow to melt:

Southern Winter Storm

A winter storm has impacted the Southern Plains and Ohio Valley just 10 days after the first winter storm of the season hit the same area. By December 5th, there were winter storm warnings from Texas to Ohio, ice storm warnings from Texas to Tennessee, freeze warnings for southern Arizona, and wind chill advisories across the Northern Plains:

One foot of snow fell as far south as Arkansas:

This storm also produced 1.25" of ice in Arkansas and Oklahoma, and 3.5" of sleet at Little Elm, TX.

Yesterday morning's (Dec 6) lows in Arizona were: Tucson 33, Safford 26, Douglas 23, Flagstaff 3, Grand Canyon -2. Extreme cold continues across the Northern Plains and Northern Rockies this morning with Jordan, MT reporting a temperature as low as -42, with a wind chill of -61.