Friday, September 30, 2011

Arctic Sea Ice 2nd Lowest on Record

From the National Snow and Ice Data Center (nsidc):

Arctic sea ice reached its lowest extent for this year (2011) on September 9, 2011. The minimum ice extent was the second lowest in the satellite record, after 2007, and continues the decadal trend of rapidly decreasing summer sea ice.

On September 9, 2011 sea ice extent dropped to 4.33 million square kilometers (1.67 million square miles). This appears to have been the lowest extent of the year, and marked the point when sea ice begins its cold-season cycle of growth.

This year's minimum was 160,000 square kilometers (61,800 square miles) above the 2007 record minimum extent, and 2.38 million square kilometers (919,000 square miles) below the 1979 to 2000 average minimum. Note that our estimated uncertainty for extent is plus or minus 50,000 square kilometers (about 20,000 square miles). The minimum ice extent this year is very close to 2007, and indeed some other research groups place 2011 as the lowest on record. At this point, using our processing and sensor series, the 2011 minimum is a close second.

Thursday, September 29, 2011

On this date in weather history

Late September is normally when we start thinking about the first freeze, not the first snowfall. But on this date in 1985, it was not only unseasonably cold, it also snowed. Granted, it was only 0.8 in. of snowfall at the Lincoln airport and it didn't hang around for more than a few hours, but I imagine it still caught most people off guard. Much of western and north central Nebraska did have significant accumulations between September 28-29, 1985 though. Here are some of the totals across the state, some of which would be impressive at any time of year:

Lincoln: 0.8 in.
North Platte: 3.0 in.
Grand Island: 3.8 in.
Sidney: 4.0 in.
Halsey: 4.0 in.
Scottsbluff: 4.8 in.
Alliance: 6.0 in.
Valentine: 18.4 in.

The early season snow was a precursor into what would be a chilly fall and early winter in Nebraska, as most of the state was in the deep freeze from mid-November to Christmas.

Thursday, September 22, 2011

U.S. Summer 2011 Climate Update

From: NCDC.
Climate Highlights — Summer 2011
The average U.S. temperature during the summer of 2011 was 74.5 degrees F (23.6 degrees C) — 2.4 degrees F (1.3 degrees C) above the long-term (1901-2000) average and the second warmest summer on record.
The unprecedented heat during the summer period (June-August) of 2011 across Texas, Oklahoma, New Mexico, and Louisiana resulted in these states having their warmest summers on record. Average temperatures for the summer in Texas and Oklahoma, at 86.8 degrees F (30.4 degrees C) and 86.5 degrees F (30.3 degrees C), respectively, exceeded the previous seasonal statewide average temperature record for any state during any season. The previous warmest summer statewide average temperature was in Oklahoma, during 1934, at 85.2 degrees F (29.6 degrees C).

During the summer, a persistent ridge of high pressure bestrode the eastern U.S., causing warmer than average temperatures east of the Rockies. Fifteen states had a summer average temperature ranking among their ten warmest. West of the Rockies, a persistent trough brought below-average temperatures to the Pacific Northwest, where Washington and Oregon were the only states across the lower 48 to have below-average summer temperatures.

Based on NOAA's Residential Energy Demand Temperature Index, the contiguous U.S. temperature-related energy demand was 22.3 percent above average during summer. This is the largest such value during the Index’s period of record, which dates to 1895.
During the summer of 2011, all states across the contiguous U.S., with the exception of North Dakota and Vermont, experienced at least one day with a location having a daily maximum temperature exceeding 100 degrees F (37.8 degrees C). A large swath of the Southern Plains and Southwest had over 30 days with a daily maximum temperature of 100 degrees F (37.8 degrees C) or warmer.

Friday, September 16, 2011

El Niño & La Niña Winter temperatures and Precipitation

This is an amazing site.

The site at the above link has maps (down to the county level) for every El Niño & La Niña showing Winter temperature anomalies and Winter precipitation anomalies for the U.S. The archive has data and maps for the period 1950 and up through last Winter 2010-2011.

Many people when they hear El Niño & La Niña assume that the climate for all El Niño events is pretty much the same and during all La Niña events is pretty much the same. That is not the case, although there are some similarities among all El Niño & some similarities among all La Niña events, there is also a large amount of variation.

For example, the two La Niña winter maps attached here, 1995-96 and 2010-11 both show a colder than normal Midwest and eastern U.S., however, the 1995-96 Winter (unlike 2010-11) had much more area with above normal temperatures in the western U.S. For a real contrast, go look at the La Niña Winter of 1999-2000 (at the above link) Temperatures were above normal for 95% of the U.S. during the La Niña Winter of 1999-2000.

Summer 2011 Global Climate Update

"Summer 2011, 3rd Warmest on Record for Global Land Surfaces"

For the June–August three month period (Northern Hemisphere summer / Southern Hemisphere winter), this was the third warmest global land surface temperature on record. This was also the 19th consecutive June–August with the average global land temperature above the 20th century average. The 2011 Northern Hemisphere summer was the second warmest on record, behind 2010, while the Southern Hemisphere winter was the eighth warmest on record. Across the globe, warmer-than-average conditions were observed across Mexico, the eastern two-thirds of the United States and Canada, and most of Europe and Asia. Cooler-than-average regions included Alaska, Chile, Argentina, Uruguay, part of western Russia, northern Kazakhstan, and northern Australia.

In northern Europe, Finland had its fourth warmest summer since records began in the early 1900s with temperatures 2.62°C (6.52°F) above the 1971–2000 average, according to the Finnish Meteorological Institute.

The June–August 2011 global ocean temperature ranked as the 12th warmest in the 132-year period of record as ENSO-neutral conditions held during June and July before returning to La Niña in August. The warmth was most pronounced across the north central, northwest, and south central Pacific, the equatorial north Atlantic, and the Labrador Sea.

Combined, the June–August global land and ocean temperature was the seventh warmest such period on record and the 35th consecutive June–August (since 1976) with the average temperature above the long-term average. Separately, it was the 26th consecutive above-average Northern Hemisphere summer and 43rd consecutive above-average Southern Hemisphere winter.

Friday, September 9, 2011

Summer 2011 Second Warmest on Record for U.S.

From NCDC: The blistering heat experienced by the nation during August, as well as the June through August months, marks the second warmest meteorological summer (June 1 - August 31) on record according to scientists at NOAA’s National Climatic Data Center (NCDC) in Asheville, N.C. The persistent heat, combined with below-average precipitation across the southern U.S. during August and the three summer months, continued a record-breaking drought across the region.

The average U.S. temperature in August was 75.7 degrees F, which is 3.0 degrees above the long-term (1901-2000) average, while the summertime temperature was 74.5 degrees F, which is 2.4 degrees above average. The warmest August on record for the contiguous United States was 75.8 degrees F in 1983, while its warmest summer on record at 74.6 degrees F occurred in 1936.

Lincoln had five days with 100 F or higher temperatures, 4 at exactly 100 F and one day at 104 F. Note the white dots on the map indicate 1 to 10 days with temperatures reaching 100 F or higher.

Thursday, September 8, 2011

New 30-Year Normals for Lincoln, NE

The official new 30 year normals (1981-2010) were released in August 2011.

Here are the monthly normal temperatures for Lincoln for the new 30-year normals (1981-2010) and the old 30-year normals (1971-2001). There is also a comparison between the two time periods. All temperatures are in degrees F.

The latest 30-year normals show the greatest warming to be taking place in the Winter months (with January seeing the most warming) and several of the Summer months show a slight cooling. The annual average temperature for Lincoln warmed 0.5 degrees comparing the new to the old 30-year normals.

Friday, September 2, 2011

Summer Plains Record Heat Wave

Record Breaking Hot Summer in The Southern Plains.

It has been a record breaking hot summer in the Southern Plains. The attached map shows the temperature departures from normal across the conterminous U.S. with a red hot bulls-eye over Texas and Oklahoma.

The following link has a table listing the number of days with 100 F or higher temperatures across the Southern Plains this year.

Many of the cities on this list had their greatest number ever record of days with 100 F or higher temperatures with some records extending back over 100 years. That means it was even hotter than during the famous dust bowl years in the 1930's.

There are some locations that have had over 90 days with temperatures of 100 F or higher.
For example:
Wichita Falls, TX : 95 days
San Angelo, TX 93 days

It has also been record dry in that area of the country, but that is another story for another posting.