Friday, March 29, 2013

Frequency of Easter Dates


1875 through 2124
Date    Years...................................................
3/22    none
3/23    1913 2008 
3/24    1940 
3/25    1883 1894 1951 2035 2046 2103 
3/26    1967 1978 1989 2062 2073 2084 2119 
3/27    1910 1921 1932 2005 2016 
3/28    1875 1880 1937 1948 2027 2032 2100 
3/29    1891 1959 1964 1970 2043 2054 2065 2111 2116 2122 
3/30    1902 1975 1986 1997 2059 2070 2081 2092 
3/31    1907 1918 1929 1991 2002 2013 2024 2086 2097 
4/1     1877 1888 1923 1934 1945 1956 2018 2029 2040 2108 
4/2     1893 1899 1961 1972 2051 2056 2113 2124 
4/3     1904 1983 1988 1994 2067 2078 2089 
4/4     1915 1920 1926 1999 2010 2021 2083 2094 
4/5     1885 1896 1931 1942 1953 2015 2026 2037 2048 2105 
4/6     1890 1947 1958 1969 1980 2042 2053 2064 2110 2121 
4/7     1901 1912 1985 1996 2075 2080 
4/8     1917 1928 2007 2012 2091 
4/9     1882 1939 1944 1950 2023 2034 2045 2102 
4/10    1887 1898 1955 1966 1977 2039 2050 2061 2072 2107 2118 
4/11    1909 1971 1982 1993 2004 2066 2077 2088 2123 
4/12    1903 1914 1925 1936 1998 2009 2020 2093 2099 
4/13    1879 1884 1941 1952 2031 2036 2104 
4/14    1895 1963 1968 1974 2047 2058 2069 2115 2120 
4/15    1900 1906 1979 1990 2001 2063 2074 2085 2096 
4/16    1876 1911 1922 1933 1995 2006 2017 2028 2090 
4/17    1881 1892 1927 1938 1949 1960 2022 2033 2044 2101 2112 
4/18    1897 1954 1965 1976 2049 2055 2060 2106 2117 
4/19    1908 1981 1987 1992 2071 2076 2082 
4/20    1919 1924 1930 2003 2014 2025 2087 2098 
4/21    1878 1889 1935 1946 1957 2019 2030 2041 2052 2109 
4/22    1962 1973 1984 2057 2068 2114 
4/23    1905 1916 2000 2079 
4/24    2011 2095 
4/25    1886 1943 2038 

Thursday, March 28, 2013

Cool March...How About April Temperatures?


I love the NOAA Reanalysis site! Its interesting to look back at past year's weather and patterns.  I looked at the MARCHES that were COOLER than this MARCH and did a composite of the APRILS that followed (20 of them). What I found isn't too mild. 

The April's that followed were still below normal on average.
  NORMAL HIGH on APRIL 1st is 53; NORMAL HIGH on APRIL 30th is 65.

Keep in mind that this is only a STATISTICAL COMPARISON NOT A DYNAMIC ONE. I didn't weed out or add any atmospheric variables that exist this year versus in the past so don't take this too literally. that said, its an interesting map; one that we will need to watch in the upcoming weeks.

If this holds true, expect highs to stay in the 50s and 60s with some stretches of mid 40s throughout the month. Let's see what the actual pattern brings!

The Dates of Easter - Earliest and Latest

Who said there isn't math in The Bible.

The article is incorrect. Easter falls on a Sunday between March 22 and April 25 from 1753 to 2400. The article is below for you to check out

From "The Economist"...

"...The earliest possible date for Easter occurs when the full moon falls on March 21st itself, in a year in which March 21st falls on a Saturday. Easter is then celebrated on Sunday March 22nd, a rare event that last happened in 1818 and will next take place in 2285. The latest possible date for Easter occurs when there is a full moon on March 20th, so that the first full moon after March 21st falls a lunar month or 29 days later, on April 18th. If April 18th falls on a Sunday, then the special Sunday rule applies, and Easter is celebrated the following Sunday, or April 25th. This last happened in 1943, and will next happen in 2038. There is therefore a 35-day window in which Easter can fall, depending on the timing of the full moon relative to March 21st."

Got it...and that's just the Western Church...phew.

Wednesday, March 27, 2013

Cleveland March Year-to-Year Comparison

March 27th: FOX8 rooftop photo of Lake Effect clouds pushing south/Cleveland Skyline

I've mentioned several times how this March is almost a polar opposite to last March. Most of the country is seeing well below temperatures all month. Here are the difference between last March and this March comparing temperatures to the averages.

Just how different has the second half of March been compared to last March 15th through the 26th in Cleveland? The drop in temperature this March since the 15th is the greatest drop of any back-to-back Marches in recorded weather history!

Here are the Marches with the largest comparisons year-to-year. How about a 32 degree difference.

Diving into the numbers further, the 3 year comparisons so even more variation. 2011: 41 degrees, last year: 63, this year 31

Its looking better and better for this cold pattern to slowly moderate next week. Stretches of snow-producing cold will be replaced by temps in the 40s. By the way, normal high is 52

Tuesday, March 26, 2013

Where Does This Winter's Temperatures Rank? Snowfall?

Rittman Snowfall on March 25th

 ...not as cold as you might think.

The last several weeks of well below normal temperatures since that one Sunday on the 12th when we
almost hit 70 has skewed our perception of the winter. This is called the "Observational Selection Bias".  This is the effect of suddenly noticing things we didn't notice that much before — but we wrongly assume that the frequency has increased.  This leads us to the RECENCY EFFECT: This is the tendency to think that more recent trends and patterns we observe (which are more recent in our minds) are a very good representation of the entire period. We perceive these biased observations as excellent predictors of what the future will bring.  

How often has someone said to you that this colder trend recently surely means that the rest of the spring will be cold?  That is the RECENCY EFFECT at work .

We averaged the high and low temperatures of each day from December 1st to March 25th for each year since 1871.  Here is the list showing where this winter ranks...surprisingly, its far down on the list of 143 winters.

The 143 year trend is all over the place...

How about snow this year?  It falls somewhere in the middle of the list...

So while we perceive this winter as so cold due to the last few week's weather, this winter sits in the middle of the list both in temperature and in snowfall.

Thursday, March 21, 2013

What is Driving this March Cold Spell?

At this point in the winter (now early Spring), we are all getting very annoyed with the cold. A few weeks ago when highs approached 70, the general populous assumed that this signified the end of the cold. The meteorological gods have had other ideas.

So what is driving this cold? The answer lies in the teleconnections derived from the pressure patterns in the higher latitudes. The North Atlantic Oscillation (NAO), Arctic Oscillation (AO) and the Pacific North American Index (PNA). I wrote extensively about each of these indices last year during our mild winter (2010-11) which you can read here. Even late in the season, these 3 teleconnections can still have a HUGE impact on the weather across the US.  As I write this, we are watching clusters of lake effect snow dropping several inches of "partly cloudy" across parts of the north coast

Back to the THREE indices...the more negative the NAO is, the stronger the northwest component which most times leads to a much stronger cold pattern. The AO is the NAO's close cousin. The more negative the AO, the better the propensity for colder periods and frequent clipper like systems. 

How strong is this NAO signature?  I looked back at Marches that had more than 2 straight days with NAOs below -1.5.  Why did I pick -1.5? Currently, the NAO is well below -1.5 and falling so -1.5 was a good starting point. Checking all of the data, I could only find 6 YEARS that match:  2011, 2001, 1980, 1977, 1962 & 1952.  I didn't use 2001 because those instances occurred in early march.  I plotted the NAO from March 10th through April 4th (to get some data overlap on both ends of the plot) to see if there was a pattern. Notice that in each year, the NAO bottomed out at the end of the month in EACH YEAR. Whether this is a statistical correlation or something more atmospheric, I'm not sure. More analysis would be needed to figure this out.

Where does this year rank in comparison to these years?  WAY BELOW THIS GRAPH. In fact, one model yesterday had the NAO dropping to -4.

Even if this model is a bit aggressive in its NAO forecast, we are still looking at temperatures staying WELL BELOW NORMAL for a while.

Is this cold spell some sort of record for this time of year? Surprisingly, not even close. Here is where this year's cold spell (starting after that warm Sunday a few weeks back) ranks ALL-TIME...How about 40th!

Tuesday, March 19, 2013

Do March Cold Stretches Lead to Milder Aprils?

Everyone is asking if this abnormally cold pattern will lead to a colder or warmer April?

Let's look at the Aprils of the past statistically after stretches of cold in mid to late March similar to this one.  The coldest stretches between March 15th and 24th were in these years. (So far, this stretch in 2013 (assuming that the extended forecast holds) is ranked 8th coldest.)

How were the temperatures in the following Aprils in these years? Here are the composites for each year. 4 of the 8 occurred before 1910.

APRIL 1906
APRIL 1960
APRIL 1872
APRIL 1885
APRIL 1896
APRIL 1956
APRIL 2006
APRIL 1967
The only years in this list that had COLDER than normal temperatures in NORTHERN OHIO were 1956 and 1885.  So statistically, the chances for an April with ABOVE NORMAL TEMPERATURES after a stretch of cold like what we are experiencing in this part of March are fairly good. Let's hope the actual meteorological pattern matches up.

Monday, March 18, 2013

Why is the Winter Pattern Lingering So Long?

This is the most asked question over the last week or so of northern Ohio residents. March of 2013 is the polar opposite of March of 2012 when we had a handful of 80 degree days en route to the warmest March in 140+ years of record keeping.  So far this March (through the 17th) temperatures rank 67th coldest---right in the middle of the 142 years of record keeping.

I only have a few minutes this morning due to the winter precipitation moving through the area along with my multiple weather segments so I'll keep my analysis brief:

The answer lies within the 3 major indices that govern our patterns. The AO (Arctic Oscillation), the NAO (North Atlantic Oscillation) and the PNA (Pacific North American Pattern). Last winter (2011-12) I wrote an extensive explanation on these three teleconnections. You can read it here.

Each index plays a different role at different times of year. In the summer, many of these indices are not as strong. But in March, they can play havoc with the development of spring warmups. The Sunday we had recently with temperatures at 70+ was the one bright spot in this colder than normal pattern.

Recently, these indices that measure the strength of arctic storm patterns (AO, NAO) are strongly negative which mean colder than normal. (graphic courtesy: Dr. Ryan Maue)

The PNA (pacific north american pattern) has been trending positive. All of these keep the NW flow aloft firmly entrenched keeping temperatures well below normal across the eastern US.

Not to worry. The "nickel-and-dime" cold punches WILL some point :)

Tuesday, March 12, 2013

Where Does This Winter's Average Temperature Rank in Northern Ohio?

The results come on the heals of a Facebook post I made asking to rank this winter on a scale of 1 to 10, ten being the worst winter. Surprisingly, most people said it was between a 3 and a 5. A few were above 7, a handful were down at the bottom of the scale. I thought it would have ranked higher given the comments recently after the temperatures fell more than 20 degrees.

So what does the data say?  I ran the numbers of all the years since 1871 from December 1st through March 10th and ranked the past 13 winters. You'll see last winter is close to the top of the list. This winter was much further down the list.  Here is the graph:

Now the ranks of each winter since 2000. Surprisingly, many of the winters since 2000 are fairly far down the list away from the warmer winters historically. This year ranks 32nd warmest of 143 winters!

Friday, March 08, 2013

Why are stocks rising when growth is so slow?

I love to read about a variety of topics as many of you know. One of the subjects is economics and the present state of the economy. Why? There is so much I don't know. Simple as that.

The big question in the midst of this market rally is why are stocks so high while unemployment/growth is so slow? Here are some excerpts from a well known economist which tells the story beautifully: I paraphrased the article. The link to the complete article is below

"The financial crisis and the bursting of the housing bubble created a situation in which almost all of the economy’s major players are simultaneously trying to pay down debt by spending less than their income...

...right now everyone wants to save and nobody wants to invest...excess savings are driving down borrowing costs...Stocks are high, in part, because bond yields are so low, and investors have to put their money somewhere.

It’s also true, however, that while the economy remains deeply depressed, corporate profits have staged a strong recovery. And that’s a bad thing! Not only are workers failing to share in the fruits of their own rising productivity, hundreds of billions of dollars are piling up in the treasuries of corporations that, facing weak consumer demand, see no reason to put those dollars to work."


Hence, the markets are soaring but income is hardly rising, unemployment is high and the overall upward trend of the US GDP is not high enough to make a dent in the unemployment rate. 

Basically, We have a long way to go!

Thursday, March 07, 2013

Behavorial Meteorology: Why Can't We Handle Forecasts

We generally hate probabilities in life...especially in weather forecasts. For our minds to grasp probabilities, we need to be able to handle multiple possible outcomes at once. Weather has many, many outcomes over a large area due to the changing initial conditions. Typically, our brains work much better with a theme that is linear. That is with a beginning, middle and an end. In other words, we want to know if it will rain or not. We crave "black and white" scenarios. We love a good narrative, a story, versus something that is data driven.

I try to explain the multiple variables that go into a forecast for the many locations around the viewing area which will be affected. For most, it goes in one ear and out the other.  Our minds don't easily recognize the probability elements and instead, we favor a story that fits our biases. If someone doesn't like the forecaster, they have less of a chance of being believed. If it doesn't rain over their house when the probability is 90% chance of rain, the forecaster is wrong. Even if the rest of the area was hit with a good downpour.  We find elements of the story that fit our preconceived notions about the subject and hold onto them even if data says otherwise. Remember the psychology when you hear a weather forecast. Its never as straight forward as we'd like it to be.