Christmas Storms

RowlettTornado01

It was a terrible Christmas for sure. The warm Chrsitmas last week made it felt like late Spring or early Summer. Christmas was very warm throughout America, east of the Rocky Mountains. The warm weather could not last forever in Winter. Cold air from the north came and it clashed with the warm air. That leads to severe weather including tornadoes.

Christmas2015_SurfaceTemperatureAnomaly_NA

The Eastern two thirds of America is abnormally warm. However, the warm and humid air by itself does not create storms. It needs lift. There is a large upper level trough to the west and upper level ridging to the east. That kind of setup is favorable for severe weather. The upper level trough brings in cold air from Canada and Alaska. The upper level ridging keeps things warm throughout America.

Christmas2015_500mb_GeopotentialHeightAnomaly_NA

The day before Christmas Eve, known as Festivus, severe weather hit the Southeast and Midwest. It mainly centered around Kentucky, Indiana, Arkansas, and Missouri. There were numerous reports of tornadoes, hail, and strong wind. Christmas Eve had tornadoes hit the Southeast, Alabama and Mississippi. Once the tornadoes and storms past, 15 people lost their life. It is not over yet.

Christmas2015TennesseeTornado01

Christmas2015TennesseeTornado02

Christmas sees more tornadoes and severe weather in the Southeast, again over Alabama. The tornadoes do not stop there. The day after Christmas, tornadoes strike the Dallas/Fort Worth Metroplex. A large EF-4 tornado hits Garland and Rowlett, destroying houses in its path. Once it is all over, 11 people lost their life.

RowlettTornado02

RowlettTornado03

Christmas2015Storm

There is also flooding from heavy rain. The heavy rain is mostly over Southeast Alabama, Southwest Missouri, Northeast Oklahoma, and Northwest Arkansas. The heavy rain is from the same storm system and warm air clashing. Many areas see 6 to 12 inches of rain in a 7 day period. Southeast Alabama saw as much as 19 inches of rain in 7 days! That is a lot for Winter! Then floodings have claimed at least 18 lives. Many areas in Missouri could see record flooding on par with 1973 and 1993.

20151228_7Day_Rainfall_Total

To make matters worse, there is an epic blizzard that hits New Mexico and West Texas. Many areas see 6 to 12 inches with isolated totals of 15 inches of snow. Talk about an epic blizzard right there!

Christmas2015ElPasoSnow

Christmas went from Fall, Spring, Summer, and Winter all at once! Talk about crazy weather! This is what El Nino can do to our weather. My Winter forecast had a higher chance for severe weather for the South and Southeast. I think this Winter will be known as the Winter of severe weather. It is not even January and February yet.

RowlettTornado04

This Christmas is a tragic one for 43 families. At least 43 people have lost their life in this severe storm. Thankfully, severe storms around Christmas are rare.

2015-2016 Winter Forecast

Snowman01

It is this time of the year. Winter is coming as Christmas is coming. It seems like Christmas comes sooner and sooner each year. One huge factor for this winter is the strong El Nino. It is one of the strongest El Nino since 1997-1998 if we go back to 1950. There were strong El Nino before 1950. 1877-1878, 1888-1889, 1896-1897, 1902-1903, 1904-1905, and 1940-1941 had strong El Nino.

Other factors to consider are Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and now Northeast Pacific Warm Pool (NEPWP). However, since this El Nino is large and strong and has significant impact, it will weigh in more than other factors listed. Since, we have a strong El Nino, here are my analog winters.

1877-1878
1888-1889
1896-1897
1902-1903
1940-1941
1957-1958
1972-1973
1982-1983
1991-1992
1997-1998

I choose these analog years because they are strong El Nino regardless of Eastern Equatorial or Modoki or Central Pacific. I did not include 1904-1905, 1987-1987, and 1992-1993 because the peak happened in Spring, unlike right now. Since, I go by divisional climate data, there is nothing before 1895, but there are local climate data before 1895, but it would be tedious to look at. However, I can look at upper air pattern and temperature anomaly in those analog years thanks to 20th Century Reanalysis Monthly Composites, which has 20CRV2c.

2015-2016Winter500mbGeopotentialAnomalyWorld

It shows troughing south of Alaska, which is a positive East Pacific Oscillation (EPO). A positive EPO is less favorable for freezes. Now, that does not mean the EPO will always be positive because it can go negative. A negative EPO would have ridging over Alaska, which means a better chance for cold blasts in the winter. There is also ridging off the east coast of Japan and surrounding Antartica.

So, how does it affect temperature and rainfall? Let’s start with temperature.

2015-2016_Analog_WinterTemperatureAnomaly_World

The Northern part of America is warm as the jet stream travels further south than normal. It is also warm throughout South America as El Nino is off the coast of South America. It is cold in the Arctic and Antartica region. El Nino also effects rain.

2015-2016_Analog_WinterPrecipitationAnomaly_World

In terms of rainfall, Southern and Western US, West Coast of South America, Central Africa, Northern Pakisan/Afghanistan, and Southeast China is wetter than normal. The wettest is the area over where El Nino is. Meanwhile, most of Eastern South America, Philpppines, Indonesia, Northern Australia, Southeast Africa, Madagascar, and Central America are going to be dry. Droughts are usually a huge problem during El Nino for those areas.

Keep in mind temperature and rainfall records often do not go back to the 19th Century in many parts of the world. Let’s take a look at divisional climate in America. The data goes back to 1895, so there will be no data available prior to 1894, which means no data for 1877-1878 and 1888-1889. Let’s start with rainfall.

2015-2016_Analog_Divisional_Rain_StandardizedAnomaly

Rainfall is heavier to the south as mentioned previously due to jet stream. The jet steam carries more storm systems over the Southern US. Meanwhile, the Northern US is drier as a result. Generally it is wetter, but not always. Here is the wettest and driest analog years.

America
Driest: 1896-1897 6.68
Wettest: 1997-1998 8.99
Analog Mean: 7.61
Analog Standard Deviation: 0.87
Overall Mean (1895-2015): 6.74
Overall Standard Deviation (1895-2015): 0.88

Texas
Driest: 1896-1897 3.49
Wettest: 1991-1992 12.72
Analog Mean: 7.09
Analog Standard Deviation: 2.63
Overall Mean (1895-2015): 4.82
Overall Standard Deviation (1895-2015): 1.83

Upper Texas Coast
Driest: 1896-1897 5.30
Wettest: 1991-1992 23.54
Analog Mean: 13.18
Analog Standard Deviation: 5.24
Overall Mean (1895-2015): 10.24
Overall Standard Deviation (1895-2015): 3.53

1896-1897 was dry overall for America including Texas and Upper Texas Coast. The wettest is 1991-1992 and 1997-1998. Overall, analog years are wetter than normal. How does temperature fare?

2015-2016_Analog_Divisional_Temperature_StandardizedAnomaly

The Southern US is cooler than normal. It is due to the perpetual cloud coverage and rain, which keeps things cooler than normal. There can also be cold blasts during a strong El Nino. Up north is warmer than normal in the winter. Some people would like it as those areas are cold in the winter. Here is the warmest and coolest analog years.

America
Coolest: 1902-1903 30.03°F
Warmest: 1991-1992 36.35°F
Analog Mean: 33.55°F
Analog Standard Deviation: 2.29
Overall Mean (1895-2015): 32.31°F
Overall Standard Deviation (1895-2015): 2.01

Texas
Coolest: 1972-1973 43.83°F
Warmest: 1991-1992 46.90°F
Analog Mean: 46.90°F
Analog Standard Deviation: 1.89
Overall Mean (1895-2015): 47.28°F
Overall Standard Deviation (1895-2015): 2.31

Upper Texas Coast
Coolest: 1972-1973 50.13°F
Warmest: 1997-1998 55.93°F
Analog Mean: 53.47°F
Analog Standard Deviation: 1.09
Overall Mean (1895-2015): 53.97°F
Overall Standard Deviation (1895-2015): 2.63

America is warmer overall in those analog years. That is due to the Northern US being warmer than normal. Texas and Upper Texas Coast is cooler than normal due to all the rain and clouds over the Lone Star State. The combination and cooler and wetter weather increases the chance for winter weather for Southeast Texas. What about snow?

In Southeast Texas, snow has occurred in these analog years.
1896-1897
1957-1958
1972-1973

The data record from Houston Weather Bureau (WB) in January 1897 has handwriting I cannot read too well. It says that snow and a blizzard happened in Houston on January 25, 1897. There was a hard freeze from January 25-29. It did not go above freezing between January 26-29. It is a freeze in par with other huge freezes in January/February 1951 and February 1989 freezes! February 12, 1958 saw a snow flurry. The Winter of 1972-1973 had three snowfall events of over one inches. That is unheard in Houston area! It is also one of the coldest winters on record for Upper Texas Coast on par with 1977-1978 and 2009-2010. There is no weather record from 1877-1878 in Southeast Texas, so I do not know what the weather was like that time. 1888-1889 had no snowfall recorded. There were some freezes in January and February of 1889. It was more of a wet winter that time. This is from Houston WB records.

Another thing to consider is severe weather. I created a GIS heat map of tornado, hail, and strong wind for those analog years. The tornado, hail, and strong wind is from the 1950s and later. They are all within 300 miles. Let’s start with tornadoes.

2015-2016_Winter_Analog_Tornado

Tornadoes are generally rare in the Winter, but they can happen. In analog winters, tornadoes are most common from Southeast Texas, Louisiana, Arkansas, and Missouri. The second hot spot is Central Florida. El Nino causes the jet stream to go further south, allowing storms to track over. These storms dump heavy rain and can produce severe weather. Let’s look at strong winds from storms.

2015-2016_Winter_Analog_Wind

The entire Eastern US is most at risk for strong winds. Also, Central California is at most risk for strong winds. Strong winds can from severe thunderstorms and storm systems, a tight pressure gradient of low and high pressure, or a cold front passes. So, what effect does El Nino have on hail in the winter?

2015-2016_Winter_Analog_Hail

The highest risk for hail is Texas, Oklahoma, Arkansas, Louisiana, Southern Kansas, and Southern Missouri. There is also a higher risk in Alabama and Georgia and Southern Florida. Not a good thing as severe weather is generally more common in an El Nino winter in the Southern US.

The heat map could give us a good idea where severe weather events could happen this winter. Frankly, I would be just as concerned about severe weather, especially in the Southern US. I would not be surprised if this winter will be known as the winter of severe weather besides winter weather.

Past El Nino does not guarantee that this El Nino will be similar. All El Nino’s are different. Regardless, I expect an interesting winter coming. So fasten your seatbelt tightly. It will be a rough ride for sure.

Christmas 2011

It is almost Christmas and wonder what it is like in Southeast Texas? Here are weather records that goes back to 1921. Keep in mind that the official weather station for Houston has moved from Downtown Houston to Bush Interncontinental Airport.

Houston Weather Branch 1921-1968

Year High Low Average Rainfall
1921 53 31 42 0
1922 75 51 63 0
1923 59 48 53.5 0
1924 37 27 32 0
1925 59 45 52 T
1926 48 33 40.5 0.28
1927 56 43 49.5 0.01
1928 58 43 50.5 0
1929 69 41 55 0
1930 58 46 52 1.31
1931 70 53 61.5 0
1932 68 50 59 0
1933 74 59 66.5 0
1934 78 64 71 T
1935 57 43 50 T
1936 72 58 65 0
1937 75 61 68 0
1938 51 46 48.5 1.42
1939 45 41 43 1.81
1940 70 54 62 0.48
1941 67 52 59.5 0.46
1942 79 67 73 0
1943 38 35 36.5 0.01
1944 77 65 71 0.29
1945 62 46 54 0
1946 73 50 61.5 0
1947 51 34 42.5 0
1948 64 41 52.5 0
1949 65 46 55.5 T
1950 74 53 63.5 0
1951 75 61 68 0.13
1952 54 42 48 0
1953 55 33 44 0
1954 70 57 63.5 T
1955 79 63 71 0
1956 61 41 51 0
1957 67 53 60 0.32
1958 54 42 48 0.05
1959 63 54 58.5 T
1960 65 47 56 0
1961 63 42 52.5 0
1962 57 48 52.5 0.04
1963 70 45 57.5 0
1964 82 59 70.5 0
1965 57 40 48.5 0
1966 48 40 44 0.13
1967 64 48 56 0
1968 66 48 57 0

Bush Intercontinental Airport 1969-2010

Year High Low Average Rainfall
1969 69 41 55 0
1970 65 39 52 0
1971 73 59 66 0
1972 66 34 50 0
1973 51 45 48 T
1974 51 43 47 0.12
1975 46 35 40.5 T
1976 61 45 53 0.59
1977 59 39 49 0
1978 66 30 48 0
1979 70 33 51.5 0
1980 50 30 40 0
1981 56 33 44.5 0
1982 74 51 62.5 1.64
1983 28 11 19.5 0
1984 64 49 56.5 0.01
1985 45 29 37 0
1986 68 41 54.5 0
1987 78 51 64.5 0.04
1988 65 50 57.5 T
1989 61 20 40.5 0
1990 44 26 35 0
1991 56 37 46.5 0
1992 62 51 56.5 T
1993 64 33 48.5 0
1994 64 34 49 0
1995 60 42 51 0
1996 59 32 45.5 0
1997 59 38 48.5 0
1998 41 31 36 0
1999 58 36 47 0
2000 57 48 52.5 T
2001 54 33 43.5 0
2002 50 32 41 0
2003 61 43 52 T
2004 49 32 40.5 0
2005 69 44 56.5 0
2006 53 39 46 0.01
2007 62 33 47.5 0
2008 74 60 67 0
2009 49 32 40.5 0
2010 46 37 41.5 T

The Ghost of Christmas Past sometimes has to deal with rain and other times has to wear shorts. The Ghost of Christmas Past has only dealt with snow once in 2004. Snow on Christmas is not likely this year. Rain will be main problem this time. Santa Claus better have rain gear to wear for the rainy Christmas Eve. Christmas Eve 2010 was wet, especially at night. So, the Ghost of Christmas Past does return.