Heavy snowfall in a warming world
A major new winter storm is headed east over the U.S. today, and threatens to dump a foot or more of snow on Philadelphia, New York City, and surrounding regions Tuesday and Wednesday. Philadelphia is still digging out from its second top-ten snowstorm of recorded history to hit the city this winter, and the streets are going to begin looking like canyons if this week's snowstorm adds a significant amount of snow to the incredible 28.5" that fell during "Snowmageddon" last Friday and Saturday. Philadelphia has had two snowstorms exceeding 23" this winter. According to the National Climatic Data Center, the return period for a 22+ inch snow storm is once every 100 years--and we've had two 100-year snow storms in Philadelphia this winter. It is true that if the winter pattern of jet stream location, sea surface temperatures, etc, are suitable for a 100-year storm to form, that will increase the chances for a second such storm to occur that same year, and thus the odds have having two 100-year storms the same year are not 1 in 10,000. Still, the two huge snowstorms this winter in the Mid-Atlantic are definitely a very rare event one should see only once every few hundred years, and is something that has not occurred since modern records began in 1870. The situation is similar for Baltimore and Washington D.C. According to the National Climatic Data Center, the expected return period in the Washington D.C./Baltimore region for snowstorms with more than 16 inches of snow is about once every 25 years. This one-two punch of two major Nor'easters in one winter with 16+ inches of snow is unprecedented in the historical record for the region, which goes back to the late 1800s.
Figure 1. Car buried in Virginia by "Snowmageddon" on February 8, 2010. Image credit: wunderphotographer Brabus Cave.
Top 9 snowstorms on record for Philadelphia:
1. 30.7", Jan 7-8, 1996
2. 28.5", Feb 5-6, 2010 (Snowmageddon)
3. 23.2", Dec 19-20, 2009 (Snowpocalypse)
4. 21.3", Feb 11-12, 1983
5. 21.0", Dec 25-26, 1909
6. 19.4", Apr 3-4, 1915
7. 18.9", Feb 12-14, 1899
8. 16.7", Jan 22-24, 1935
9. 15.1", Feb 28-Mar 1, 1941
The top 10 snowstorms on record for Baltimore:
1. 28.2", Feb 15-18, 2003
2. 26.5", Jan 27-29, 1922
3. 24.8", Feb 5-6, 2010 (Snowmageddon)
4. 22.8", Feb 11-12, 1983
5. 22.5", Jan 7-8, 1996
6. 22.0", Mar 29-30, 1942
7. 21.4", Feb 11-14, 1899
8. 21.0", Dec 19-20, 2009 (Snowpocalypse)
9. 20.0", Feb 18-19, 1979
10. 16.0", Mar 15-18, 1892
The top 10 snowstorms on record for Washington, D.C.:
1. 28.0", Jan 27-28, 1922
2. 20.5", Feb 11-13, 1899
3. 18.7", Feb 18-19, 1979
4. 17.8" Feb 5-6, 2010 (Snowmageddon)
5. 17.1", Jan 6-8, 1996
6. 16.7", Feb 15-18, 2003
7. 16.6", Feb 11-12, 1983
8. 16.4", Dec 19-20, 2009 (Snowpocalypse)
9. 14.4", Feb 15-16, 1958
10. 14.4", Feb 7, 1936
Heavy snow events--a contradiction to global warming theory?
Global warming skeptics regularly have a field day whenever a record snow storm pounds the U.S., claiming that such events are inconsistent with a globe that is warming. If the globe is warming, there should, on average, be fewer days when it snows, and thus fewer snow storms. However, it is possible that if climate change is simultaneously causing an increase in ratio of snowstorms with very heavy snow to storms with ordinary amounts of snow, we could actually see an increase in very heavy snowstorms in some portions of the world. There is evidence that this is happening for winter storms in the Northeast U.S.--the mighty Nor'easters like the "Snowmageddon" storm of February 5-6 and "Snowpocalypse" of December 19, 2009. Let's take a look at the evidence. There are two requirements for a record snow storm:
1) A near-record amount of moisture in the air (or a very slow moving storm).
2) Temperatures cold enough for snow.
It's not hard at all to get temperatures cold enough for snow in a world experiencing global warming. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, the globe warmed 0.74°C (1.3°F) over the past 100 years. There will still be colder than average winters in a world that is experiencing warming, with plenty of opportunities for snow. The more difficult ingredient for producing a record snowstorm is the requirement of near-record levels of moisture. Global warming theory predicts that global precipitation will increase, and that heavy precipitation events--the ones most likely to cause flash flooding--will also increase. This occurs because as the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. This extra moisture in the air will tend to produce heavier snowstorms, assuming it is cold enough to snow. Groisman et al. (2004) found a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events in the U.S. over the past 100 years, though mainly in spring and summer. However, the authors did find a significant increase in winter heavy precipitation events have occurred in the Northeast U.S. This was echoed by Changnon et al. (2006), who found, "The temporal distribution of snowstorms exhibited wide fluctuations during 1901-2000, with downward 100-yr trends in the lower Midwest, South, and West Coast. Upward trends occurred in the upper Midwest, East, and Northeast, and the national trend for 1901-2000 was upward, corresponding to trends in strong cyclonic activity."
The strongest cold-season storms are likely to become stronger and more frequent for the U.S.
The U.S. Global Change Research Program (USGCRP) began as a presidential initiative in 1989 and was mandated by Congress in the Global Change Research Act of 1990 (P.L. 101-606), which called for "a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change." This program has put out some excellent peer-reviewed science on climate change that, in my view, is as authoritative as the U.N.-sponsored Intergovernmental Panel on Climate Change (IPCC) reports. In 2009, the USGCRP put out its excellent U.S. Climate Impacts Report, summarizing the observed and forecast impacts of climate change on the U.S. The report's main conclusion about cold season storms was " Cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent".
The report's more detailed analysis: "Large-scale storm systems are the dominant weather phenomenon during the cold season in the United States. Although the analysis of these storms is complicated by a relatively short length of most observational records and by the highly variable nature of strong storms, some clear patterns have emerged (Kunkel et al., 2008).
Storm tracks have shifted northward over the last 50 years as evidenced by a decrease in the frequency of storms in mid-latitude areas of the Northern Hemisphere, while high-latitude activity has increased. There is also evidence of an increase in the intensity of storms in both the mid- and high-latitude areas of the Northern Hemisphere, with greater confidence in the increases occurring in high latitudes (Kunkel et al., 2008). The northward shift is projected to continue, and strong cold season storms are likely to become stronger and more frequent, with greater wind speeds and more extreme wave heights". The study also noted that we should expect an increase in lake-effect snowstorms over the next few decades. Lake-effect snow is produced by the strong flow of cold air across large areas of relatively warmer ice-free water. The report says, "As the climate has warmed, ice coverage on the Great Lakes has fallen. The maximum seasonal coverage of Great Lakes ice decreased at a rate of 8.4 percent per decade from 1973 through 2008, amounting to a roughly 30 percent decrease in ice coverage. This has created conditions conducive to greater evaporation of moisture and thus heavier snowstorms. Among recent extreme lake-effect snow events was a February 2007 10-day storm total of over 10 feet of snow in western New York state. Climate models suggest that lake-effect snowfalls are likely to increase over the next few decades. In the longer term, lake-effect snows are likely to decrease as temperatures continue to rise, with the precipitation then falling as rain".
Figure 2. The annual average number of snowstorms with a 6 inch (15.2 cm) or greater accumulation, from the years 1901 - 2001. A value of 0.1 means an average of one 6+ inch snowstorm every ten years. Image credit: Changnon, S.A., D. Changnon, and T.R. Karl, 2006, Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States, J. Applied Meteorology and Climatology, 45, 8, pp. 1141-1155, DOI: 10.1175/JAM2395.1.
More heavy snowstorms occur in warmer-than-average years
Another interesting result from the Changnon et al. (2006) paper (Figure 2) is the relationship between heavy snowstorms and the average winter temperature. For the contiguous U.S. between 1900 - 2001, the authors found that 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. In other words, the old adage, "it's too cold to snow", has some truth to it. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000. The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches between 1901 - 2000. However, a separate paper by Houston and Changnon (2009), "Characteristics of the top ten snowstorms at First-Order Stations in the U.S.", found that there was no upward or downward trend in the very heaviest snowstorms for the contiguous U.S. between 1948 - 2001, as evaluated by looking at the top ten snowstorms for 121 major cities.
Commentary
One can "load the dice" in favor of events that used to be rare--or unheard of--if the climate is changing to a new state. It is quite possible that nature's weather dice have been loaded in favor of more intense Nor'easters for the U.S. Mid-Atlantic and Northeast, thanks to the higher levels of moisture present in the air due to warmer global temperatures. It's worth mentioning that heavy snow storms should be getting increasingly rare for the extreme southern portion of the U.S. in coming decades. There's almost always high amounts of moisture available for a potential heavy snow in the South--just not enough cold air. With freezing temperatures expected to decrease and the jet stream and associated storm track expected to move northward, the extreme southern portion of the U.S. should see a reduction in both heavy and ordinary snow storms in the coming decades.
The CapitalClimate blog has a nice perspective on "Snowmageddon", and Joe Romm of climateprogress.org has some interesting things to say about snowstorms in a warming climate.
References
Changnon, S.A., D. Changnon, and T.R. Karl, 2006, , "Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States", J. Appl. Meteor. Climatol., 45, 1141.1155.
Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64-85.
Kunkel, K.E., P.D. Bromirski, H.E. Brooks, T. Cavazos, A.V. Douglas, D.R. Easterling, K.A. Emanuel, P.Ya. Groisman, G.J. Holland, T.R. Knutson, J.P. Kossin, P.D. Komar, D.H. Levinson, and R.L. Smith, 2008: Observed changes in weather and climate extremes. In: Weather and Climate Extremes in a Changing Climate: Regions of Focus: North America, Hawaii, Caribbean, and U.S. Pacific Islands [Karl, T.R., G.A. Meehl, C.D. Miller, S.J. Hassol, A.M. Waple, and W.L. Murray (eds.)]. Synthesis and Assessment Product 3.3. U.S. Climate Change Science Program, Washington, DC, pp. 35-80.
Congratulations, New Orleans!
Congratulations to everyone in New Orleans, for the Saints' Super Bowl victory! It's great to the see the city celebrating after enduring so many years of hardship in the wake of Hurricane Katrina.
Jeff Masters
Reader Comments
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Not to mention the fact that these "scientists" try to censor those who disagree with them.
Link
Hey, Dan, if you ever need a translation, just call on me, I would be glad to help out. See why Google translations never come out correctly. LOLOLOL
Hey everyone..
Cane it is now about acting to prevent the worst, face it. If you really would have concerns you would go here http://climate.gov and read. Period.
Yeah the transalation was not so bad, funny article though - 90% of the sidewalks are come with ice ;) Peopel didn't expected this ... very unusal winter.
Come by and see what your donations are doing for the people of Haiti!
you wanna fight about Global Warming? :o)
It was not!!!!!!!!!! You need to source comments like this!!!!
; )
Sorry... I'll get my emotions of happiness peer reviewed...
it's okay. I peer reviewed his statement and found it to be accurate.
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LOL!
Suggestion: Do not give a woman with crampons any spikes or hooks -- although you would have have an unforgettable experience, you would definitely need a helmet!
lol nah, im going to stay out of that one. I have my opinions, but I find it more interesting to read the "banter". I enjoy reading opposite opinions on GW ideas....it challenges my own and forces me to really think of supporting evidence for my OWN opinions-- and if they are right!
Actually, for my Graduate class, we are reading two polar opposite books on GW and policies, etc. It is a really interesting read if you read them side by side!! They are:
"Environmental Governance Reconsidered" and "Re-Thinking Green".
VERY interesting pair!
ONE MORE DRY DAY IS IN STORE FOR THURSDAY THOUGH IT WILL BE COOL AS
HIGH CLDS BEGIN TO INCRS AHEAD OF THE NEXT STORM SYSTEM TAKING SHAPE
ACROSS THE WRN GULF OF MEXICO. THIS SYSTEM WILL TRACK ACRS OR EVEN
TO THE SOUTH OF SOUTH FL FRIDAY AFTN/NIGHT WITH A WEAK BUT FAST
MVG SFC LOW. AHEAD OF THIS SYSTEM IT WILL STILL BE COLD THURSDAY
NIGHT BUT PSBLY NOT AS COLD REGION WIDE AS MID/HIGH CLDS MAY START
TO INCRS. WILL HOLD TEMPS NEAR OR JUST ABV FREEZING ACROSS THE
SAME AREAS MENTIONED ABV FOR NOW. FRIDAY WILL FEATURE INCRSG
CLOUDS WITH A POTENTIALLY STEADY MODERATE TO OCCASIONALLY HEAVY
RAIN DVLPG DURING THE DAY AS OVERRUNNING/ISENTROPIC LIFT
INCRS...LASTING INTO THE OVERNIGHT USING THE GFS/ECMWF TIMING FOR
THIS SYSTEM. TEMPS MAY BE WELL BELOW GUIDANCE FRIDAY AND IT COULD
VERY WELL BE A COOL/RAW DAY IF THE CLDS/RAIN DVLP EARLY ENOUGH.
THEREAFTER...WEAK SFC HIGH PRESSURE WILL SETTLE ALONG THE GULF CST
ALLOWING CONDS TO CLEAR OUT SOME FOR THE UPCOMING WEEKEND...THOUGH
THE AMPLIFYING ERN CONUS UPR TROUGH WILL LIKELY ALLOW FOR PERIODS
OF HIGH CLDS AT TIMES. TEMPS WILL COOL SLIGHTLY ONCE AGAIN OVER
THE WEEKEND.
&&
Oh yeah, climate.gov isn't biased at all...
LOL I remember a few years back using one of those translation programs. Do it about three of four times and it becomes unreadable. Absolutely hilarious. Fortunately all my German friends speak good English. (well, before too many beers) :) Was always funny to hear them correcting each other at parties, especially as the night wore on.
Maybe it has something to do with the storm track, local met here in Tampa said the Low might take a very unusual southerly track.
+1
Thanks for posting some reading material on both sides of, er, discussion.
Not, at all. I just find it amusing that many cite the IPCC when it is fact that the IPCC uses non-peer reviewed studies in it's claims. Also, it has been shown that even peer-reviewed studies are HIGHLY suspect.
I'm doing research on human-induced Global Warming, are those books found online??
No problem! Hopefully it will make BOTH sides think about what they REALLY believe or support! not sayign either side is right or wrong-- both sides have valid points, and both sides have their faults.
I know. It's a shame. But as you well know, he lost his, errrr, backside when I tried to move him from the old car to the new one. (Can you say rump roast on the dash?) LOL
Cane, SS, I am so used to seeing attack behaviour in here on either side of the argument that I'm impressed when someone, anyone provides sources...when did the issue become a war?
debate: "Debate or debating is a formal method of interactive and representational argument. Debate is a broader form of argument than logical argument, which only examines consistency from axiom, and factual argument, which only examines what is or isn't the case or rhetoric which is a technique of persuasion. Though logical consistency, factual accuracy and some degree of emotional appeal to the audience are important elements of the art of persuasion, in debating, one side often prevails over the other side by presenting a superior "context" and/or framework of the issue, which is far more subtle and strategic."
Where does it say in there that name calling, mudslinging or character assasination are part of the form?
We have commentators that incite this behaviour; the Rush Limbaughs and Glenn Becks of the world have decided that being civil is not the best way to be a demagogue and people follow their lead and it's not just the conservative members of our community here that are to blame for this behaviour. Apparently it's a crime for people to believe something that we don't, so the gloves are off. This country has become one giant verbal (and physical) fist fight and it's a damned shame...it's like we're all scholl children with no control over our emotions and no mechanisms in place to get control over them...when did that happen?
'Tis a good question, and I refer you to our graduate school poster, HHGal. Madam, or Mademoiselle? Will you please respond to the poster GTcooliebai? TIA.
It goes to show we really don't know that much about the climate and weather.
It's tough to get any sizeable portion of C/SFL below freezing with bath water on either side and a hot tub in the middle, winds have to be perfect. Radiational cooling is probably forecast to be best there.
81-4 day temperature outlook...
I resemble that remark.... :-)
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The GFS has track significantly and anomalously further south compared to the rest of the computer forecast models. The CMC, ECMWF and NAM track the low across the northern GOM which appears much more reasonable at this time and considering the tracks of past lows this 2009-2010 winter season.
If you are looking for a significant snowfall event then the GGEM advertises this featuring a well rounded surface low and deep trough axis behind the low collapsing mid level heights. Snow would stretch from Texas all the way to the panhandle of Florida and accumulate. The ECMWF is less aggressive with the low but still conducts decent surface cyclogenesis and snowfall with the 850mb 0C isotherm reaching the coastal areas similar to the GGEM. The NAM out to 84 hours is much more conservative and would likely limit snowfall to areas well north of the I-10.
Teleconnections, -NAO, strongly negative AO, and a PNA, favors the diving of cold air into the deep south and an active jet stream. Right now I am leaning towards the ECMWF and the GFS Ensembles which isn't too dramatic but reasonable.
8-14 day precip outlook...
Is this right?
:)
Or does it just mean the GFS "sees" more snow for the south?
damn, I wish I understood a word of that! I'm guessing it means it's gonna be cold.
Yes, by all means let's use facts. But let's also NOT cherry-pick the dataset to prove whatever we want. Instead, let's see what the dataset actually tells us about ice outs on Lake Winnipesaukee.
If you examine these data carefully, you will find, as I did, that -- surprise, surprise -- they actually SUPPORT the idea that Lake Winnipesaukee is WARMER now than it was 100 years ago, and that ice out is now consistently occuring EARLIER that it did 100 years ago.
The mean ice out date I compute from the full dataset is approximately 19-20 April. Examine the ice out date for the first 20 years, 1887-1906, and the last 20 years, 1990-2009. You will find that, compared with the average ice out date:
1) Ice out occured MORE THAN ONE WEEK EARLY 7 times in the most recent 20-year period (1991, 1998, 1999, 2000, 2002, 2006, 2009) compared with 3 times in the earliest 20-year period (1892, 1902, 1903).
2) Ice out occured MORE THAN ONE WEEK LATE 5 times in the earliest 20-year period (1887, 1888, 1893, 1899, 1904) compared with ONLY ONCE in the most recent 20-year period (2001).
3) Ice out occured MORE THAN TWO WEEKS LATE 3 times in the earliest 20-year period (1887, 1888, 1893) compared with ZERO times in the most recent 20-year period.
4) The AVERAGE ice out date for the earliest 20-year period is approximately 23 April, or about 3 days LATER than the 100-year average.
5) The AVERAGE ice out date for the most-recent 20-year period is approximately 18 April, or about 2 days EARLIER than the 100-year average.
6) Consequently, the AVERAGE ice out date is now about FIVE DAYS EARLIER than it was 100 years ago.
And that, my blog buddies, is EXACTLY what you'd expect from a gradual warming trend.
So... Regarding 2001... Can you say "outlier"? Yes, I thought you could. :)
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS, MD
300 PM EST TUE FEBRUARY 09 2010
6-10 DAY OUTLOOK FOR FEB 15 - 19 2010
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: EXCELLENT, 5 ON A SCALE OF 1 TO 5,
DUE TO VERY GOOD AGREEMENT AMONG ALL MODEL ENSEMBLES.
It's usually rated from a 2 to a 4.
The GFS gives no snow to the south or the north with the system that will form in the GOM. I am discarding the GFS for now as it is an outlier. The ECMWF and GGEM advertise snow for the south but this does not appear to be Miller A type storm that would ride up the coast.
Think he's saying the chance of snow in the area I live in, Florida panhandle, is possible according to what he see's.
Not saying he's specifically mentioning just my area, but my take is...he does see a chance of the white stuff here.
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