I'm Dreaming of a Dry Christmas

Most people in South Carolina usually dream of a white Christmas.  There have been so few times that it has happened in this area.  In fact Climate Central did the calculations and the chances are less that 1% of seeing a white Christmas in Columbia.  Where is the best place to be?  See the map below:

The chance of seeing a white Christmas across the U.S.  Click on the image for a larger version.  Image Credit: Climate Central.

Even though the map shows the historical odds of a white Christmas, the actual amount of snow in a given location can vary a lot from year to year due to natural weather variations.  For example, this year, U.S. snow cover in mid-December was the largest it’s been in a decade.  Outside the U.S., it’s worth noting that Siberia, generally one of the coldest places on Earth for this time of year, had a scorching November with temperatures up to 14°F higher than normal.  That warm trend has continued into December, leaving a "snow shortage".  We can identify with a snow shortage.

Weather's Ups & Downs

It has been like a roller coaster for temperatures since late October beginning with a freeze on the 26^th Columbia, SC, when the temperature dropped to 30°F.  This came after an exceptionally warm fall.  Here is a look at the ups and downs since October 26^th:

Month	Date	Temp
Oct	26	30°
	30	82°
Nov	4	38°
	6	77°
	9	32°
	10	72°
	14	23°	New Record Low
	18	85°	New Record High; Trace of Snow Evening
	19	38°
	22	76°
	25	22°
	26	71°
	28	23°
Dec	6	82°	Record High Tied
	13	25°
	21	81°	New Record High

The forecast for the 22^nd of December is for record high temperatures with much colder weather returning for Christmas Day.  Thus the roller coaster will continue for a while.

What is causing this?

The Winter 2013-14 Outlook

The Climate Prediction Center (CPC) released its latest outlook for the coming winter this morning.  This year’s forecast is challenging as there are few climate signals that are strong enough to give clues as to what to expect.  Thus the outlook is based more on trends.

Climate outlooks are probabilistic forecasts meaning that they give you information about the chances of seeing departures from the average.  It cannot tell you when or where snowstorms will occur.  The outlook is designed to tell you what the average conditions will be.

This year warmer than normal conditions are expected for the Southwest, the South-Central U.S., parts of the Southeast, New England and western Alaska.  The Northern Plains and the Alaskan Panhandle are expected to see colder than normal conditions.  South Carolina has an equal chance of seeing warmer, near normal, or colder conditions as there are no clues to guide the forecast.

The temperature outlook for the 2013-14 winter.  Click on the image for a larger view.  Image Credit: NOAA.

Climate Change & Fall Colors

The colors of fall are greatly anticipated in this part of the country.  Some plan vacations around a particular week trying to be in the peak of color.  Normally tourists plan for the middle two weeks of October to enjoy the color of western North Carolina.  However, I was surprised on a recent trip into that area to see how late the change of color was this year.

Near Lake Adger in western North Carolina (about 10 miles east of Hendersonville) on October 21, 2013.  Notice the lack of color.  There was still a lot of green.  Click on the image for a larger view.  Image Credit: Jim Gandy

It got me thinking about the set-up this year.  The summer had been very wet, but fall had turned out to be quite dry.  It should have been a good year for color in western North Carolina.  This is not to say that there wasn’t color, but you didn’t see the splash of all the colors at once.

I came across a blog post by a plant physiologist at Appalachian State University which put this in perspective.  Dr. Howie Neufeld goes into detail about how trees change color and what factors can affect fall colors.  It is quite informative and worth a read, but here is an excerpt on the two main factors:

South Carolina's Wettest Summer

This past summer was cool and wet for Columbia and this was the topic of a previous post.  It turns out that Columbia was not alone.  In fact some areas had much more rain than Columbia.  The mountains of South Carolina saw record rainfall for the summer with an average of over 40 inches.  On August 6^th over 5 inches of rain fell in the Upstate resulting in one drowning death in Pickens County.

Summer rainfall averaged for the mountains of South Carolina (division 1) since 1895.  2013 was the wettest on record.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.

The wettest areas were in the Upstate, Pee Dee, north coastal, and central divisions of South Carolina.  These divisions saw record summer rainfall while all other divisions were at least in the top 10 wettest.

A ranking of summer rainfall for South Carolina since 1895.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.

A ranking of summer rainfall for South Carolina since 1895 with other states in the U.S.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.

Karen Fizzles

Karen, the eleventh tropical storm of the season, dissipated along the central Gulf coast Sunday morning.  This was a relief to that area of the country, but was not expected from the forecast three days before.  The Federal Emergency Management Agency (FEMA) had already begun to recall personnel on furlough from the government shutdown.  Keep in mind that meteorologists at the National Weather Service (NWS) and National Hurricane Center (NHC) were already on the job, just not getting paid.

So what happened?

The tropical storm formed Thursday morning north of the Yucatan Peninsula and in my last post you can see what the track models were suggesting.  However, the storm was already being affected by a southwesterly shear aloft and dry air covered much of the western Gulf of Mexico.

The visible satellite picture of Karen for 21z Thursday, October 3. 2013.  The center of circulation is north of the Yucatan Peninsula.  Notice the asymmetry in the storm with all of the thunderstorms east of the center.  Dry air west of the center kept storms to a minimum.  Click on the image for a larger view.  Image Credit: UCAR.

Karen Will Affect South Carolina

Tropical Storm Karen formed just north of the Yucatan Peninsula Friday morning (correction: that should be Thursday morning).  The system had been moving northwest through the western Caribbean since early in the week.  Conditions were finally favorable for development.

Now Karen takes aim on the U.S.  It has been moving slowly through the southern Gulf of Mexico and toward the north-northwest.  Hurricane hunters found winds of near 60 mph this morning prompting the upgrade to tropical storm status.

As of 11 p.m. EDT, Thursday, Tropical Storm Karen was 340 miles south of the mouth of the Mississippi River moving north-northwest at 10 mph.  Maximum sustained winds were 65 mph in squalls to the northeast.

The wind field around Tropical Storm Karen as of 00z October 4, 2013.  Winds are measured in knots.  The Yucatan Peninsula can be seen in the lower part of the image.  Click on the image for a larger view.  Image Credit: NOAA/NHC.

The Cool, Wet Summer of 2013

This past summer (June 1-August 31) was a great relief from the past three scorching summers.  Remember that the summer of 2010 and 2011 were back to back the warmest summers on record.  Last summer wasn’t quite as hot, but we did see the all-time record high temperature for South Carolina broken when it reached 113 F in Columbia.

It was during this time that much of the region was also battling drought.  There was some rainfall during the normal wet season of summer, but there were few wet months beginning in 2010.  In fact there were only 8 wet months out of 36 ending in 2012.  It looked like it would never change.

However, the weather pattern began to change in February of this year.  Rains began to increase, but it also got colder.  There were shifting patterns throughout the spring, but it too was cool and wet.  Then summer began with a very sluggish pattern that dominated June and July.  It was not as dominate in August, but it was still enough to keep the month on the cool side.

This weather pattern persisted for much of June and July.  Click on image for a larger view.  Image Credit: WLTX-TV.

A Tale Of Two Halves

This summer has been one of persistence across the U.S. in the general weather pattern.  The West has been too dry and the East too wet.  Severe to exceptional drought covers much of the western half of the country, while flooding and downpours have drenched the Southeast and Mid-Atlantic.  Some areas have seen relief from the devastating drought of last year and it has gotten worse for others.

The U.S. Drought Monitor for August 6, 2013.  This shows the areal extent of drought across the U.S. at this point in time.  Click on the image for a larger view.  Image Credit: NOAA/USDA.

The worst of the drought continues to be in the High Plains, but it is getting worse over much of the Southwest.  This has already led to an above normal wildfire season in the West.

Columbia's Extreme Rain Event

A complex of heavy thunderstorms formed over the Columbia, SC area last Sunday, July 21, 2012.  The heavy rains resulted in what is known as an extreme rain event.  That means that rainfall for the day had to equal or exceed 2.52 inches to be in the top 1% (99^th percentile) based on the current climate statistics.  The official total at the National Weather Service Forecast Office was 2.55 inches, thus an extreme rainfall day.

The slow moving thunderstorms unleashed a torrent of rain producing two to five inches of rain in a couple of hours.  The highest rainfall totals stretched from Lexington to Forest Acres on the east side of Columbia.  Reports of 4.89 inches came in from west of Lexington, 4.56 inches from West Columbia, and 3.48 inches from Forest Acres.

As one can imagine with all of the rain this summer the heavy rains led to flooding.  All of the usual spots flooded, but there were areas not prone to seeing so much water.  Flooding was reported in parts of Forest Acres.  Rain was so heavy in West Columbia that motorists on I-26 had to slow down and pull over in some cases.

A graph of the water levels for Rocky Branch Creek for July 17-24, 2013.  Note that a previous flood occurred on the 17th with bigger flood on the 24th.  Click on the image for a larger view.  Image Credit: USGS.

  

Water rushed into Rocky Branch Creek that flows through the Five Points Area.  By the time it reached Whaley Street it was the third highest flood on record.  The water level reached 11.46 feet, whereas flood stage is at 7.2 feet.  Roads were closed and cars were flooded.

From One Extreme To Another

June was a month of extremes across the U.S. Record heat dominated the West, where all time record June temperatures were being set in multiple states. Meanwhile, the same weather pattern that supported the prolonged, intense heat across the West locked in an extremely wet set up across the East. Not only were numerous daily rainfall records set, but both Philadelphia, PA and Macon, GA, ended up with their wettest June ever.

Some of the extreme weather across the U.S. in June 2013.  Click on image for a larger view. Image Credit: Climate Central.

You can also add Augusta, GA, to the wettest June on record.  Bush Field in Augusta received 10.83 inches of rain which was 6.11 inches above normal. An observer near Martinez, northwest of August, received 16.02 inches for June.  This is remarkable since that area of Georgia and South Carolina had been suffering from nearly 3 years of drought until recently.

2013 Hurricane Season: Very Active?

It has been a little over a month since the last of the 2013 hurricane season forecasts were made.  All of the forecasts call for an active season with the possibility of a very active season.  The third named storm of the season (Chantal) formed late on July 6, which is just over a month earlier than when the average “C” storm forms.  Is this a sign of a very active season?  Given conditions in the tropics I would say, yes.

Tropical Storm Chantal moves into the eastern Caribbean Sea.  Click on image for a larger view.  Credit: NOAA.

Two storms have already formed in the deep tropics (Barry, Chantal) and one is a Cape Verde storm which usually doesn’t get going until mid-August.  As Jeff Masters points out on his blog:

"Most years do not have named storm formations in June and July in the tropical Atlantic (south of 23.5°N); however, if tropical formations do occur, it indicates that a very active hurricane season is likely. For example, the seven years with the most named storm days in the deep tropics in June and July (since 1949) are 1966, 1969, 1995, 1996, 1998, 2005, and 2008. All seven of these seasons were very active. When storms form in the deep tropics in the early part of the hurricane season, it indicates that conditions are already very favorable for TC development. In general, the start of the hurricane season is restricted by thermodynamics (warm SSTs, unstable lapse rates), and therefore deep tropical activity early in the hurricane season implies that the thermodynamics are already quite favorable for tropical cyclone (TC) development."

This quote is attributed to Colorado State University researchers Phil Klotzbach and Bill Gray.

From Wet To Steamy

Drought has been the rule since the fall of 2009 in parts of South Carolina.  Only 6 out of the next 36 months saw above normal rainfall in Columbia, South Carolina until 2013.  Then the pattern changed and 2013 has been wetter than normal.  In fact, 4 out of the last 6 months have been above normal and July is likely to add to that total.

The first week of July has been extremely wet. The airport has seen 2.19 inches of rain while the city has received 4.35 inches of rain in just six days.  July is normally the wettest month of the year, but this year has been wetter than normal.  In fact, the last two weeks have been quite wet.

The map below shows the observed rainfall across South Carolina for the past two weeks ending on July 6.  Note that the area east of a line from Lancaster to Columbia to Barnwell has seen the greatest rain with 10 to 15 inches of rain in eastern Orangeburg and southeastern Clarendon counties.  The rain has been less west of the line until you get into the upstate of South Carolina.

The 14-day observed rainfall ending at 8 a.m. July 6, 2013.  Click on image for a larger view.  Image Credit: NOAA/AHPS.

Heavy rainfall has resulted in significant rises in many of the rivers with minor flooding of the Congaree River in the Columbia area.  The Congaree Swamp has seen considerable flooding over the past month closing some of the trails.  This is likely to continue as much of the flood waters from the Upstate have yet to pass through the Midlands.

So, why is this happening?  It turns out that our weather is linked to a pattern which has caused record heat in the Southwest and cooler than normal conditions in the Midwest.

Is Andrea About To Form?

Early Start

Hurricane season began June 1^st and by all accounts it is expected to be an active season.  Is the season about to get underway?  It seems the computers think so.  The vast majority of the computers have been indicating that something could form in the Gulf of Mexico this week.

There was an area of disturbed weather extending from the Yucatan Peninsula northeast into the Gulf of Mexico Monday evening.  Moisture was streaming north from the western Caribbean Sea.  No indications of development have been noted over the past 24 hours.

However, computer models suggest that thunderstorm activity will be on the increase today into Wednesday.  The latest Regional Precision Model (RPM) has a circulation forming in the Gulf north of Yucatan on Wednesday.  The system would then move north curving northeast into the Apalachee Bay on Thursday.

The 72-forecast valid Thursday evening at 00z June 7, 2013.  Click on the image for a larger view.  Image Credit: WSI.

The above model has the system coming onshore late Thursday afternoon and moving northeast toward coastal South Carolina.  That is where the heaviest rainfall would occur.  It could be breezy for the coastal sections, but the system is not expected to be very strong.

Just Another Number?

Numbers have meaning only in context.  A temperature of 98.6 degrees F is normal body temperature, but only in context of the mean.  This is not normal for every person.  The S&P 500 crossing 1600 is meaningless unless it is in context of what the market is doing.  Is it going up or down?  How far has it gone from previous levels?  Only then does the number have meaning.

A milestone was reached recently, Thursday, May 9^th, at the Mauna Loa Observatory in Hawaii.  Levels of carbon dioxide reached 400 parts per million (ppm) for the first time in human existence.  Daily measurements are made at the observatory of the gases that lead to atmospheric change.  One of the main gases monitored is carbon dioxide (CO2).  Levels of 400.03 and 400.08 ppm were measured independently by the National Oceanic & Atmospheric Administration (NOAA) and Scripps Oceanographic Institute respectively.

Mauna Loa Observatory in Hawaii.  Click on the image for a larger version.  Image Credit: NOAA/ESRL.

This was a daily mean that was measured for the first time.  Hourly measurements exceeded this number quite a few times since mid-April.  The monthly mean of CO2 will likely peak this month, at a level of about 399 ppm, and then fall until October.  It is likely to pass the 400 ppm in the spring of next year.  The yearly mean will not likely cross this level until 2015 or 2016.

A Drought Worth Having

Droughts can be quite nasty with it comes to rainfall.  However, droughts can be a good thing when it comes to severe weather.  The U.S. is currently experiencing such a drought for tornadoes.

The monthly number of tornadoes for 2013 compared to the 1981-2010 average. Click on the image for a larger version.  Image Credit: Climate Central.

The year started off looking above normal, but that quickly turned in February.  Significantly fewer tornadoes were observed in March and April.  May is normally the peak of tornado season for much of the country.  The drought has continued and will likely continue into the middle of May.  It is hard to say if it will continue beyond that, but it is likely.

A Cool Start To May 2013

Just as we were getting used to hotter springs, Mother Nature pulls a fast one.  It has been unusual to say the least for South Carolina weather since April 26^th.  Cloudy, cool conditions have been the rule with plenty of rain.  The griping has begun as many are tied of conditions we normally attribute to Seattle.

My favorite tweet during the past week has been “Breaking news: This just in – Cleveland wants its weather back.”  I’m sure those in Cleveland might think this an improvement over what they normally get in early May.

So what has been happening?  Why has it been so cloudy and cool for so long?  When will this go away so that we can get on with summer?

The first half of spring was influenced by a weather pattern associated with a negative phase of the Arctic Oscillation.  This was described in the previous post.  However, that has not driving the weather pattern recently.  Instead the jet stream has retreated to the north leaving upper-level low pressure systems isolated from the main flow.  This has resulted in a blocking pattern where weather systems slow to a crawl and can persist for days.

The weather pattern at 500 mb (~18,000 ft) on Saturday, May 4, 2013 at 12z UT.  The jet stream had retreated farther to the north leaving isolated pockets of low pressure over the mid-latitudes.  Click on the image for a larger version.  Image Credit: WLTX-TV.

A Dramatic Change This Spring

It is amazing how fast the weather pattern can change.  Temperatures were much below normal at the end of March.  There was a brief warm up at the beginning of April, but a brief cool snap followed.  Finally the cold air retreated leaving much of South Carolina with above normal temperatures.  In a matter of five days high temperatures in Columbia went from 55 degrees F on April 4^th to 87 degrees F on April 9^th & 10^th.

A previous post talked about the delay of spring this year.  High pressure centered near Greenland continued to pump cold Arctic air south into North America.  This was part of the negative phase of the Arctic Oscillation which became extreme in March.  This led to colder temperatures in March than in January.

This image shows the sea level pressure anomaly calculated from NCEP climate reanalysis data from February 25 through March 25, 2013. The area of anomalous high pressure over Greenland illustrates the negative phase of the Arctic Oscillation, by which persistent high pressure blocks Arctic air from moving eastward, causing it to drop down into the middle latitudes and is a contributing factor in keeping temperatures unseasonably cool in Canada and the US.  Click on the image for a larger view.  Image Credit: NOAA.

When Weather Becomes Climate

Note: It has been a busy three weeks which included a week of much needed vacation.  Much has happened in the interim.  I am working on a number of posts which will be rolled out in May.

Meanwhile, many people often confuse weather with climate.  You have heard the refrains like it is so cold, how could the earth be warming?  Or how can we be in a drought when we’re having a flood?  Just when does weather become climate?  Good question!  Meteorologists at the European Space Agency have produced an answer to that question.

The following video is about 12 minutes long, but it is well produced and worth the time to view it.  They have a wealth of information with which to determine climate change and it is interesting comparing weather in the early 1800’s to weather today.  I hope you enjoy this production.

Click here: When Weather Becomes Climate

ISS: Double Pass This Weekend

Finally the weather is improving and time to get outside and enjoy spring.  This weekend offers the opportunity to see the International Space Station (ISS) pass over the area twice.  Both passes will be excellent and highly visible without the aid of binoculars.

ISS streaks across the sky.  Image Credit: Andreas Möller.

The first opportunity to see ISS will be Saturday evening.  If you have an unobstructed view of the southwest horizon, you will be able to see it rise immediately beginning at 9:27 p.m.  Most will be able to see ISS by 9:30 p.m. in the southwest moving toward the northeast.  About a minute later it will pass through the constellation Orion.  You might want to try taking a time exposed picture.  It will reach its maximum altitude at 9:32:52 p.m. about two-thirds above the northwest horizon.  However, just 17 seconds later it will move into the earth’s shadow and disappear.  If you are in a dark environment, this can be quite interesting to watch.

Spring 2013: DELAYED

It’s spring!

The vernal equinox on March 20, 2013.  It is that time of year again (it happens twice) when the relative angle of Earth is perpendicular to the Sun, causing equal incoming solar energy to the Northern and Southern hemispheres - as well as equal day and nighttime. At 7:02 ET on March 20, 2013, Earth was at its equinox. At 7:45 ET, the GOES-13 satellite captured this full disk image of Earth.  Click on the image for a larger view.  Image Credit: NOAA.

Both meteorological and astronomical springs have arrived.  The vernal equinox marks the beginning of spring in the Northern Hemisphere.  This is when the vertical rays of the sun are directly over the earth’s equator and crosses the equator on its northward journey.

Funny, it doesn’t feel like spring.  Let me check the forecast:

The 5-day forecast for March 20, 2013 for Columbia, SC.  Image Credit: WLTX-TV.

Remember those groundhog forecasts from six weeks ago.  A couple of them got it right, but most got is wrong.  Not only did spring not come early, it does not appear to be in sight.

Energy And Climate

The 2013 annual meeting of the American Meteorological Society took place this past January in Austin, Texas.  One of the topics was that of energy and climate.  Billionaire T. Boone Pickens spoke on Sunday evening before the annual meeting began.  It was an enjoyable evening and interesting to hear was he had to say.

T. Boone Pickens

First, he holds a degree in geology from Oklahoma State University.  Pickens said “I’m one of the few (petroleum) geologists that agree that global warming is happening.”  He agrees that we need to do something to mitigate the effects of the warming.  It is smarter to do something to avoid the problem rather than waiting until it happens to do anything.

However, he went on to say that hydrocarbons (fossil fuels) would be with us for the next 50 years.  Pickens said that wind and solar represent just 2% of the energy generation and he didn’t think that it would become substantial until it became economically more competitive with fossil fuels.  That means a price of about $6 for natural gas (it is just under $4 today).

Pickens is against the idea of a carbon tax or cap & trade.  However, he did not say whether he agreed with the idea of ending fossil fuel subsidies.  Tom Friedman of the New York Times has an interesting article on attacking carbon emissions and the fiscal debt.