Friday, October 21, 2011

Winter 2010-11 Outlook

According to the NOAA U.S. Winter 2011-12 Outlook (December through February)
odds tilt in favor of:

  1. Pacific Northwest: colder and wetter than average. La Niña often results in below-average temperatures and increased mountain snow in the Pacific Northwest and western Montana during the winter months. This may set the stage for spring flooding in the Missouri River Basin;

  2. California: colder than average and wetter than average conditions in northern California and drier than average conditions in southern California. All of the southern part of the nation are at risk of having above normal wildfire conditions starting this winter and lasting into the spring;

  3. Northern Plains: colder and wetter than average. Spring flooding could be a concern in parts of this region;

  4. Southern Plains and Gulf Coast States: warmer and drier than average. This will likely exacerbate drought conditions in these regions;

  5. Florida and south Atlantic Coast: drier than average, with an equal chance for above-, near-, or below-normal temperatures. Above normal wildfire conditions;

  6. Ohio and Tennessee Valleys: wetter than average with equal chances for above-, near-, or below-average temperatures. Potential for increased storminess and flooding;

  7. Northeast and Mid-Atlantic: equal chances for above-, near-, or below-normal temperatures and precipitation. Winter weather for these regions is often driven not by La Niña but by the Arctic Oscillation. If enough cold air and moisture are in place, areas north of the Ohio Valley and into the Northeast could see above-average snow;

  8. Great Lakes: colder and wetter than average;

  9. Hawaii: Above-average temperatures in the western islands with equal chances of above-, near-, or below average average precipitation. Statewide, the current drought is expected to continue through the winter. Drought recovery is more likely over the windward slopes of the Big Island and Maui;

  10. Alaska: colder than average over the southern half of the state and the panhandle with below average precipitation in the interior eastern part of the state.

Thursday, October 20, 2011

Winter 2011-12 La Niña Update

La Niña conditions are expected to gradually strengthen and continue through the Northern Hemisphere winter 2011-12.

During September 2011, La Niña conditions strengthened as indicated by increasingly negative sea surface temperature (SST) anomalies across the eastern half of the equatorial Pacific Ocean. The weekly Niño indices continued their cooling trend and all are currently at or below –0.5oC . Consistent with this cooling, oceanic heat content (average temperature anomalies in the upper 300m of the ocean, remained below-average in response to a shallower thermocline across the eastern Pacific Ocean. Also, convection continued to be suppressed near the Date Line, and became more enhanced near Papua New Guinea. In addition, anomalous low-level easterly and upper-level westerly winds persisted over the central tropical Pacific. Collectively, these oceanic and atmospheric patterns reflect the continuation of La Niña conditions.

Currently, La Niña is not as strong as it was in September 2010. Roughly one- half of the models predict La Niña to strengthen during the Northern Hemisphere fall and winter. Of these models, the majority predict a weak La Niña. In addition, a weaker second La Niña winter has occurred in three of the five multi-year La Niñas in the historical SST record since 1950. However, the NCEP Climate Forecast System predicts a moderate-strength La Niña this winter and one model predicts a strong La Niña, which rivals last year’s peak strength.There is uncertainty as to whether this strong amplitude will be achieved. Thus, at this time, a weak or moderate strength La Niña is most likely during the Northern Hemisphere winter.

Across the contiguous United States, temperature and precipitation impacts associated with La Niña are expected to remain relatively weak during the remainder of the Northern Hemisphere early fall, and to strengthen during the late fall and winter. It is important to note that the strength of U.S. impacts is not necessarily related to the strength of La Niña across the equatorial Pacific. During October-December 2011, there is an increased chance of above-average temperatures across the mid-section of the country. Also, above-average precipitation is favored across the Pacific Northwest, along with a higher probability for drier-than-average conditions across much of the southern tier of the country

Tuesday, October 18, 2011

Global Temperature Anomalies September 2011

The Earth experienced its eighth warmest September since record keeping began in 1880. The annual minimum Arctic sea ice extent was reached on September 9 and ranked as the second smallest extent since satellite records began in 1979.

This monthly analysis from NOAA’s National Climatic Data Center is part of the suite of climate services NOAA provides government, business and community leaders so they can make informed decisions.

Global Temperature Highlights: September 2011

· The combined global land and ocean average surface temperature for September was the eighth warmest on record at 59.95 degrees F (15.53 degrees C), which is 0.95 degrees F (0.53 degrees C) above the 20th century average of 59.0 degrees F (15.0 degrees C). The margin of error associated with this temperature is +/- 0.20 degrees F (0.11 degrees C).
· Separately, the global land surface temperature was 1.57 degrees F (0.87 degrees C) above the 20th century average of 53.6 degrees F (12.0 degrees C), making this the fourth warmest September on record. The margin of error is +/- 0.43 degrees F (0.24 degrees C). Warmer-than-average conditions occurred across Europe, northern and western Africa, western Russia, the western and northeastern United States, Canada, and Mexico. Cooler-than-average regions included much of eastern Asia, and part of the central United States.
· The September global ocean surface temperature was 0.72 degrees F (0.40 degrees C) above the 20th century average of 61.1 degrees F (16.2 degrees C), making it the 14th warmest September on record. The margin of error is +/- 0.07 degrees F (0.04 degrees C). The warmth was most pronounced across the north central and northwest Pacific Ocean and within about the 30°N–40°N latitude belt across the Atlantic.
· The United Kingdom marked its warmest September since 2006 and sixth warmest in the last 100 years, at 2.7 degrees F (1.5 degrees C) above the 1971–2000 average.
· Spain had its warmest September since 1990 and fifth warmest for the past 50 years, at 3.2 degrees F (1.8 degrees C) above the 1971–2000 average.

La Niña Update-Forecast, October 2011

La Niña Update-Forecast, October 2011
from IRI (the International Research Institute) for Climate and Society.

Climatologists know that El Niño and La Niña can have a Strong influence on our winter weather patterns in North America. So what is it looking like for this coming Winter?

Most of the set of dynamical and statistical models (see graph) predict La Niña conditions through this coming Winter season. Several computer models keep conditions neutral and only one forecasts a return to El Niño conditions.

The graph in this posting shows forecasts made by dynamical and statistical models for SST in the Nino 3.4 region for nine overlapping 3-month periods.

Note that the expected skills of the models, based on historical performance, are not equal to one another. The skills also generally decrease as the lead time increases.

Thirdly, forecasts made at some times of the year generally have higher skill than forecasts made at other times of the year--namely, they are better when made between June and December than when they are made between February and May.

Differences among the forecasts of the models reflect both differences in model design, and actual uncertainty in the forecast of the possible future SST scenario.

Wednesday, October 12, 2011

La Niña and El Niño Winters, Lincoln, NE Snowfall

Lincoln, NE, Snowfall During
La Niña, El Niño & Nada NiñoWinters

It is true that La Niña and El Niño events can significantly influence weather patterns in the U.S. However, the question to be asked is whether there is a significant influence on the winter weather during each of these events in Lincoln, NE.

The attached data table is a climatology of snowfall in Lincoln during La Niña, El Niño, and neutral (Nada Niño--my terminology) Winters. The Winter snowfall months were broken into October 1-December 31 (OND) and January 1-March 31 (JFM). This was done to see if there is a difference in the early part of winter compared to the later half of winter. The "30 year normals" refers to all snowfall data 1981-2010 combining La Niña, El Niño & Nada Niño events for that 30 year time period.

During the OND time period, La Niña averaged the least snowfall, El Niños averaged the most snowfall. However, during the second half of winter, La Niñas averaged the most snowfall and El Niño events averaged the least amount of snowfall. However, do note the huge range (variation) in the snowfall amounts during La Niña,El Niño and Nada Niño (neutral) events. For example, La Niña-JFM time periods, although averaging 18.2 inches of snowfall have seen as much as 41.0 inches and as little as 5.3 inches of snowfall. This makes it very difficult to forecast snowfall totals for Lincoln based only on the occurrence of a La Niña event.

Monday, October 10, 2011

This day in weather history-October 10

Lincoln, Nebraska

October 10, 2011:

low 57 F, high 70 F, am rain; pm sun

October 10, 2009:

low 27 F; high 38 F, am SNOW; pm cloudy, cold.

The photo attached shows a snow covered Lincoln, NE, on October 10. 2009.

This early season snowfall was in fact the 3rd earliest snowfall in the Lincoln, NE, snowfall data records. For more information check out the following link: October 10, 2009 snowfall

Sept. 2011 U.S. Statewide Temperature Rankings

From NCDC:

Climate Highlights — September 2011

•During September, a persistent upper-level weather pattern brought above-average temperatures to the western third of the country, below-average temperatures to the central United States, and above-normal temperatures to the Northeast.
•The average U.S. temperature in September was 66.9 degrees F (19.4 degrees C), which is 1.5 degrees F (0.8 degrees C) above the long-term (1901-2000) average. •Above-normal temperatures dominated the western United States, with five states — California, Idaho, Nevada, Oregon, and Washington — having one of their ten warmest Septembers on record.
•A persistent upper-level low pressure system was associated with 14 states having below-normal September temperatures across the central United States. Mississippi tied its ninth coolest September on record.
•Eight states in the Northeast had September temperatures among their ten warmest — Connecticut, New Hampshire, New Jersey, New York, Maine, Massachusetts, Rhode Island, and Vermont

Tuesday, October 4, 2011

September 2011 Lincoln Climate Summary

September 2011 Climate Summary Lincoln, NE.

The graph shows the daily highs and lows (top and bottom of each vertical bar) and the normal highs (red line) and normal lows (blue line).


HIGHEST 95F 09/01
LOWEST 35F 09/23
AVG. MAXIMUM = 75.1 (normal = 78.7F, departure from normal = -3.6F)
AVG. MINIMUM = 47.9 (normal = 53.4F, departure from normal = -5.5 F)
MEAN = 61.5 (normal = 66.0F,departure from normal = -4.5F)


Total = 1.33 inches (normal = 3.02 inches, departure = -1.69 inches