Atlantic Sunrise in NC

January 2012 Climate Update

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North Carolina Climate, the monthly newsletter of the State Climate Office of NC, covers information on experimental local seasonal forecasting, as well as a monthly climate summary for December with impacts across the state.
PDF version available for printing.

 

Experimental Local Seasonal Forecasting

Weather Generators are statistical models that allow for the output from coarse resolution global climate models used for seasonal forecasting to be projected or downscaled to local scales. That is, weather generators can be used to provide more localized projections of larger scale seasonal climate forecasts. Unlike other techniques, these generators produce multiple scenarios at a daily timescale for a given season, which can be used to provide forecast guidance for precipitation and temperature, the probabilities of having above average precipitation or temperatures, or the likelihood of total precipitation in a season being more or less than a user defined threshold.

Using weather generators and the Climate Forecast System (CFS) model, the State Climate Office of North Carolina is developing an experimental local seasonal forecasting product. This product will display several parameters for precipitation and temperature, including historical averages, forecast values, and forecast departure from normal for weather stations in the southeastern U.S. Using Google Maps to display the forecast, the user will also be able to select each station and get more forecast data for each station. This option will allow the user to view both what is forecast for a season as well as what is normally observed during a season at that station. The finished product will allow the user to find the forecast for stations closest to them for several pre-defined parameters, as well as for user defined thresholds of interest (e.g. the probability of total precipitation being more than 20 inches) and compare these forecasts to historical averages.

For more information about this product in development or to provide feedback on what you would like to see included in this product, please contact us - sco@climate.ncsu.edu

 

Climate Summary: December Was Warm!

Temperature and Precipitation by climate division
Departures from Normal for December 2011
Based on Preliminary Data
Temperature and Precipitation Departures from Normal

After very cold Decembers in 2009 and 2010, December 2011 ended as the 13th warmest in North Carolina since 1895. Statewide, average temperatures were generally more than 4 degrees above normal. This is most evident in daily maximum temperatures where most reporting stations ranked December as the 10 warmest, and many (including Charlotte, Greensboro, Raleigh, Wilmington, New Bern, Elizabeth City) had maximum temperatures ranked in the top 5 warmest for all Decembers.

Precipitation patterns varied across the state in December, with above-normal precipitation in western NC and very dry conditions in eastern NC. Across the coastal plain, December 2011 ranked as the 5th driest December since 1895.

Precipitation for December 2011
Based on estimates from NWS Radar
Data courtesy NWS/NCEP
MPE Precipitation


Precipitation for December 2011: Percent of Normal
Based on estimates from NWS Radar
Data courtesy NWS/NCEP
MPE Precipitation Percent of Normal

The pattern observed in December 2011 is fairly typical during La Niña events. La Niña is the name given to the cold phase of the El Niño – Southern Oscillation, when ocean temperatures in the eastern tropical Pacific Ocean are much cooler than normal. This ocean temperature change is associated with a shift in widespread thunderstorm activity across the tropical Pacific Ocean, and results in a general shift in storm tracks across North America. Typically, La Niña events are associated with drier conditions across the southern tier of the US, including central and eastern NC.


Figure Courtesy of the Wall Street Journal

While temperatures during La Niña event also tend to be above-normal across the southern US, the relationship between La Niña and temperatures isn’t as strong as the relationship between La Niña and precipitation. Indeed, temperatures last winter were quite cold, even though we had a moderate La Niña event last winter as well. Instead, atmospheric patterns such as the North Atlantic Oscillation (NAO) have a much stronger influence on the temperatures in NC. When the NAO is negative, we are more likely to see colder weather. When the NAO is positive, NC is more likely to be warm. In December 2010, the NAO was negative. In December 2011, the NAO was... you guessed it... quite positive. To learn more about ENSO, NAO, and other climate patterns interact and affect our weather, visit the Global Patterns section on our website.

Severe weather in December 2011 was limited to a single storm system that moved across the state on December 7th, producing strong winds and causing damage. Later in the month on December 27th, a strong winter storm caused sustained high winds primarily in central and eastern NC.

Local Storm Reports for December 2011
Preliminary Count of LSRs courtesy National Weather Service
http://www.nc-climate.ncsu.edu/lsrdb/index.php
LSR Summary for December 2011

 

Impacts to Agriculture and Water Resources

While drought isn't a concern for most agricultural sectors in NC in December, water supply recharge is. The colder months are when North Carolina generally recharges its groundwater, river, and reservoir supplies. While the cooler half of the year doesn’t necessarily produce more precipitation across the state, the nature of that rainfall is different. Widespread storms help to recharge water supplies more effectively than localized thunderstorms. The other big factor for winter recharge is the low evaporation and plant transpiration rates. During the cold seasons, nearly every drop that falls goes to recharge. In contrast summer evaporation rates are so high that much of what may fall from a single thunderstorm is returned to the atmosphere within days.

The lack of rainfall in eastern NC has resulted in drought impacts to river and groundwater supplies in those areas. If dry conditions persist, it may also start to impact winter grain production for growers.


US Drought Monitor for North Carolina
Courtesy NC DENR Division of Water Resources

December 2011 Drought Monitor

Statewide Summary for December 2011

As part of the monthly newsletter, the SCO provides a basic summary of monthly conditions for ECONet stations. A daily version of this product for all locations that have an automated reporting station is available online at:
http://www.nc-climate.ncsu.edu/cronos/review

Station
Avg Daily
Max Temp
Avg Daily
Min Temp
Total
Rainfall
Avg Daily
Wind Speed
Max Daily
Wind Speed
Vector Avg
Wind
Aurora, NC (AURO)
61.8° F
(+5° F)
4 mi
42.9° F
(+8° F)
4 mi
1 in
2.8 mph
26.1 mph
0.9 mph
West (269°)
Boone, NC (BOON)
53.4° F
(+9.8° F)
1 mi
33.2° F
(+10.8° F)
1 mi
5.1 in
5.2 mph
39.6 mph
3.8 mph
West (266°)
Buckland, NC (BUCK)
59.2° F
(+6° F)
15 mi
35° F
(+5.2° F)
15 mi
1.1 in
2.1 mph
24.1 mph
0.7 mph
West Southwest (248°)
Burnsville, NC (BURN)
52.2° F
(+2° F)
8 mi
31.2° F
(+7.2° F)
8 mi
5.2 in
3.4 mph
28 mph
1.4 mph
North Northwest (333°)
Castle Hayne, NC (CAST)
63.4° F
(+4.1° F)
0 mi
39.4° F
(+3.5° F)
0 mi
0.4 in
3.7 mph
29.7 mph
1.3 mph
Northwest (321°)
Clayton, NC (CLAY)
59° F
(+5.9° F)
3 mi
38.8° F
(+7.3° F)
3 mi
1.2 in
4.3 mph
36.1 mph
1.6 mph
West Southwest (254°)
Clayton, NC (CLA2)
60.6° F
(+7.5° F)
3 mi
36.1° F
(+4.6° F)
3 mi
1.2 in
1.7 mph
20.3 mph
0.5 mph
West (279°)
Clinton, NC (CLIN)
61.3° F
(+5.8° F)
0 mi
38° F
(+4° F)
0 mi
0.6 in
4.3 mph
29.8 mph
1.7 mph
Southeast (135°)
Fletcher, NC (FLET)
55.1° F
(+5.7° F)
0 mi
32.3° F
(+7.2° F)
0 mi
5.2 in
2.8 mph
22 mph
1.5 mph
North (350°)
Franklin, NC (WINE)
45.1° F
(-5.3° F)
11 mi
30.8° F
(+4.6° F)
11 mi
9.2 in
7.3 mph
34.4 mph
4.4 mph
West (277°)
Goldsboro, NC (GOLD)
60.6° F
(+3.5° F)
5 mi
36.6° F
(+1.1° F)
5 mi
0.6 in
3.2 mph
38 mph
1.3 mph
South Southwest (198°)
Greensboro, NC (NCAT)
57° F
(+6.4° F)
12 mi
36.8° F
(+5.4° F)
12 mi
3.1 in
3.1 mph
32.3 mph
1.7 mph
West Southwest (242°)
Hendersonville, NC (BEAR)
46.2° F
(-5.8° F)
7 mi
33.4° F
(+5.1° F)
7 mi
5.7 in
11.6 mph
50.2 mph
6.4 mph
West (265°)
High Point, NC (HIGH)
57.3° F
(+4.4° F)
2 mi
35.5° F
(+3° F)
2 mi
3.5 in
1.9 mph
19 mph
0.8 mph
West Southwest (258°)
Jackson Springs, NC (JACK)
58.8° F
(+5.9° F)
0 mi
39.6° F
(+5.7° F)
0 mi
1.3 in
4.8 mph
36.8 mph
0.6 mph
West (267°)
Kinston, NC (KINS)
60.7° F
(+1.4° F)
0 mi
38.8° F
(+2.7° F)
0 mi
0.5 in
4.6 mph
33.4 mph
1.7 mph
West Southwest (250°)
Lewiston, NC (LEWS)
58.5° F
(+3.5° F)
0 mi
37.2° F
(+4.3° F)
0 mi
0.9 in
4.4 mph
35.1 mph
1.6 mph
West Southwest (254°)
Lilesville, NC (LILE)
60.8° F
(+6.2° F)
9 mi
39.8° F
(+5.4° F)
9 mi
0.9 in
4.7 mph
20.6 mph
2.2 mph
North Northeast (16°)
New London, NC (NEWL)
59.1° F
(+5.6° F)
2 mi
34.6° F
(+4.2° F)
2 mi
3 in
2.9 mph
40.7 mph
0.6 mph
West Northwest (301°)
Oxford, NC (OXFO)
57.2° F
(+5.2° F)
0 mi
37.6° F
(+7.3° F)
0 mi
2.4 in
2.6 mph
27.6 mph
1.6 mph
Southwest (236°)
Plymouth, NC (PLYM)
59.9° F
(+2.4° F)
2 mi
37.7° F
(+1.7° F)
2 mi
0.7 in
5.7 mph
38.9 mph
1.7 mph
West Northwest (293°)
Raleigh, NC (LAKE)
58.9° F
(+4.7° F)
0 mi
38.2° F
(+3.3° F)
0 mi
1.4 in
5.1 mph
38 mph
2.2 mph
West (263°)
Raleigh, NC (REED)
58.8° F
(+6.7° F)
3 mi
38.9° F
(+5.4° F)
3 mi
4.2 in
3.2 mph
28.1 mph
1.2 mph
West Northwest (283°)
Reidsville, NC (REID)
56.2° F
(+5.2° F)
0 mi
38.2° F
(+7.7° F)
0 mi
3.6 in
4 mph
24.8 mph
2.3 mph
West (270°)
Rocky Mount, NC (ROCK)
59.1° F
(+4.2° F)
0 mi
37.4° F
(+3.7° F)
0 mi
1.1 in
4.2 mph
32.6 mph
1.5 mph
West Southwest (251°)
Salisbury, NC (SALI)
57.5° F
(+6.2° F)
0 mi
34.5° F
(+6.2° F)
0 mi
3.1 in
2.2 mph
24.7 mph
1 mph
West (259°)
Siler City, NC (SILR)
58.2° F
(+5.5° F)
5 mi
33.8° F
(+2.2° F)
5 mi
1.8 in
3.4 mph
32.9 mph
1 mph
West Southwest (258°)
Wallace, NC (WILD)
63.1° F
(+3.2° F)
8 mi
36.1° F
(-0.9° F)
8 mi
0.5 in
4.1 mph
45.2 mph
0.9 mph
West Northwest (283°)
Waynesville, NC (WAYN)
54.9° F
(+4.8° F)
0 mi
30.8° F
(+6.8° F)
0 mi
5.6 in
1.6 mph
28.7 mph
0.2 mph
West (275°)
Whiteville, NC (WHIT)
63° F
(+3.4° F)
0 mi
37.7° F
(+3.2° F)
0 mi
0.5 in
2.7 mph
24.8 mph
0.4 mph
West (281°)
Williamston, NC (WILL)
60.2° F
(+4.7° F)
4 mi
38.4° F
(+4° F)
4 mi
1 in
2.7 mph
25 mph
1.1 mph
West (260°)
Legend:
Parameter
Parameter's value approximated from hourly data.
( +/- Departure from normal )
Distance to reference station

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