Time to Plant

I have been advising gardeners to delay planting tender plants this year due to a weather pattern that has been in place since late October, 2013.  The pattern made it more likely for a late freeze.  Normally the last freeze would occur in the Midlands by late March.  Most would simply wait until Easter, but Easter is quite late this year.  The latest freeze was on March 27^th and it was a hard freeze with a low of 28° F.  It was very close to freezing on March 31^st with a low of 33° F, but there was frost that morning.

Another cold, dry air mass is making its way south and computer models have been suggesting that a frost or freeze might occur on Thursday, April 10^th.  High pressure will settle over the area with clear skies, light winds, and dry air for Thursday morning.  The forecast for Columbia is for a low near 40° F that morning, but outlying areas may drop into the mid 30s.  This would be enough for a light frost in low-lying protected areas due to radiational cooling at night.

This will likely be the last chance of a frost or freeze.  If it does not happen then the previous dates will be the last freeze or frost.  The chance of a frost or freeze on April 10^th was strong enough to advise gardeners to wait.  The seven-day forecast reveals that it will be time to plant this weekend.

The 7-day forecast made Wednesday, April 9, 2014 for Columbia, SC.  Click on the image for a larger view.  Image Credit: WLTX-TV.

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.

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.

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.

Winter Outlook for 2012-13

The Climate Prediction Center released its early outlook for the upcoming winter this morning.  Much of the western U.S. will see warmer than normal temperatures while cooler than normal temperatures are expected for the Florida peninsula.  Equal chances of above or below normal temperatures are forecast for much of the East.

Much of the West will be dry particularly in the Pacific Northwest.  The Central Gulf region is expected to be wetter than normal.  This may help ease the drought in Georgia and South Carolina.

Click on either graphic for a larger version or go here for the temperature map and here for the precipitation map.  Image Credit: NOAA\CPC.

How Cold Does It Have To Be?

As we close in on the last quarter of the year (and the end of baseball’s regular season), 2012 is on track to be the country's hottest year ever recorded. But as Yogi Berra says, “It ain't over 'til it's over.”

So how cold would it need to be for the rest of the year to miss the record?

Click on the image to see the high resolution version.  Image Credit: Climate Central.

Pretty darn cold. As you can see in the graphic above, based on temperature data from NOAA’s NCDC, if we have normal fall and winter temperatures every month for the rest of the year, we will clearly break the record (yellow line). If it stays warmer than average, we will break the record by even more (orange line). In order to miss breaking the record as the hottest year ever recorded in the United States, the months of September through December would each need to be among the coolest third of those months on record (green line).

The 2012 Hurricane Outlook

The Atlantic Basin has the most variable hurricane activity in the world and thus has become a challenge for meteorologists.  There seems to be a fascination with knowing what the season will be like, even if you can’t forecast where they may strike.

The Tropical Meteorology Project at Colorado State University has been making forecasts of the Atlantic hurricane seasons for the past 29 years.  It explains the need to forecast hurricane seasons this way:

“We issue these forecasts to satisfy the curiosity of the general public and to bring attention to the hurricane problem. There is a general interest in knowing what the odds are for an active or inactive season. One must remember that our forecasts are based on the premise that those global oceanic and atmospheric conditions which preceded comparatively active or inactive hurricane seasons in the past provide meaningful information about similar trends in future seasons. This is not always true for individual seasons. It is also important that the reader appreciate that these seasonal forecasts are based on statistical schemes which, owing to their intrinsically probabilistic nature, will fail in some years. Moreover, these forecasts do not specifically predict where within the Atlantic basin these storms will strike. The probability of landfall for any one location along the coast is very low and reflects the fact that, in any one season, most U.S. coastal areas will not feel the effects of a hurricane no matter how active the individual season is.”

Image Credit: SCMED Operations Center.

Every year South Carolina gears up for the expectation of hurricanes.  The state has a state-of-the-art facility to monitor hurricanes and emergency events.  Plans are reviewed and renewed.  Everyone is encouraged to become aware of their local situation and if need be know what routes are to be used for evacuations.  It is important to have hurricane kits and to update them each year.  This is also important for land-lovers since the effects of hurricanes can extend far inland.

Drought Worsens in South Carolina

Droughts are hard to define.  Meteorological droughts are prolonged periods with less than average precipitation, but the prolonged period is nebulous.  How many weeks or months must go by before a drought is declared?  Again this depends on how much precipitation has occurred.  Obviously if no precipitation occurs then it doesn't take long to enter a drought.  Defining when a drought started can also be difficult.  Thus, you often do not know that you are in a drought until it gets serious.

Remember December 2009?  The precipitation total for that month in Columbia was 9.31 inches, almost three times the normal value.  It was a record wet December.  In addition the four month of September through December totaled 25.96 inches which was a record for that four month period.  What happened?  A strong El Nino was in progress and most of the rain that year came in just that four months.

Click on image for the larger version.

In the 28 months since that time there have only been four months of above normal rainfall.  So in retrospect we have been in a period of drought since January 2010.  The rainfall deficit has been enormous during this time.  The deficit in Columbia has reached 25.57 inches in the past 28 months.  However, it is much worse along the Savannah River where Augusta has amassed a deficit of 38.71 inches in the same time period.  Thus the western part of South Carolina is in worse shape than the northeastern part of the state and this is reflected in the USDA Drought Monitor.

Summer 2012: A Burning Question

People are always asking me if the summer will be hot.  I tell them that this is Columbia, it is always hot.  I often add that the only thing that separates us from hell in the summertime is a screened door.

After this year’s amazingly mild winter, the obvious question is: will this summer be just as amazingly hot?  This is a question that I am already getting from viewers.  Keep in mind that the past two summers have each been record hot summers.  Common sense might say yes, an unusually warm winter will likely be followed by an unusually warm summer — but in this case, common sense would be wrong.

This chart shows the 10 mildest winters ever recorded at Metropolitan Airport, in blue, along with the summers that followed, in red. (This winter doesn’t appear at all, warm as it was, because the summer hasn’t happened yet.) And the answer is… there’s no pattern at all. A winter that’s warmer than average is sometimes followed by a warm summer, but sometimes it’s followed by a pretty average summer, or even an unusually cool one.

Click on the image to see a larger version, but for an interactive version of the graph click here.  Image Credit: Climate Central.

So what is in store for the Midlands this summer?

Winter Was Warm, But March Is %#!@^

Winter was the fourth warmest on record for the U.S. according to the National Climatic Data Center (NCDC).  Here winter is defined as the months of December through February, also known as meteorological winter.  The map below shows that most of the warm weather was east of the Rockies with near normal conditions in the West.

Statewide rank of winter temperatures for 2011-2012.  Image Credit: NOAA/NCDC.

Enter March.  This supposed to be a time of change, a transition from winter to spring.  However, this month has simply been a continuation of the trends in winter and more so.  It has been unseasonably warm over all, but the west coast of the U.S.  In fact, temperatures have been averaging more than 10 degrees F above normal in the Midwest.

Mean temperature anomalies for the U.S. for March 1-16, 2012.  Image Credit: NOAA/CPC.

The Outlook for February

It has been an unusually warm, dry winter for the midlands of South Carolina.  In 125 years of records in Columbia this winter is currently the 19th warmest on record for the period of December 1 through January 20.  The rainfall picture has be dismal.  There is a deficit of 2.92 inches since December 1st which means that we have had less than half the normal rainfall.  This includes the heavy rain that occurred today which was also the election primary for the Republican Party (0.75 in., Saturday, January 21).

The Climate Prediction Center (CPC) has released its outlook for February.  It calls for a continuation of the weather pattern with warmer and drier than normal conditions for the Midlands.  Thus, a warm, dry weather is most likely for the Midlands as well as South Carolina.

The Temperature Outlook for February, 2012.  Note that much of the country will be above normal.

The Precipitation Outlook for February, 2012.  Note the drier than normal conditions for the southern U.S.

Looking ahead into the spring, it looks like it will continue to be warm and dry.  In fact, warmer than normal temperatures are expected through the summer.  However, the seasonal outlooks show an interesting trend.  The chances for drier than normal temperatures decrease toward the summer.

If this is the case, then it may be quite dry for the spring which will intensify the drought.  However, there is hope that more normal rainfall may be in place by summer.  This scenario will still make for a challenging planting season.

Winter Weather Outlook Update

The Climate Prediction Center (CPC) issued the outlook for the winter 2011-2012 back in October and issued an update at the beginning of December.  The winter months are considered to be December, January, and February, because these are the three coldest months of the year.  Climate oscillations like the El Nino/La Nina oscillation tend to make the forecasting of the winter season a little easier.  The wild card is usually the Arctic Oscillation.

This year the forecast looked like this:

Map shows U.S. areas predicted to have well above (red) or well below (blue) normal winter temperatures in 2011-2012.  Image credit NOAA/CPC.

Map shows U.S. areas predicted to have well above (green) or well below (tan) normal winter precipitation in 2011-2012.  Image credit: NOAA/CPC.

The outlook for South Carolina was for the winter to be warmer than normal and drier than normal.  So far the forecast has been on track.  The preliminary data indicates that December 2011 was the 14th warmest and 10th driest on record for Columbia, South Carolina.  Mean temperatures across the U.S. looked like this in December:

Mean temperatures across the U.S. from December 1-30, 2011.  Image credit: NOAA/CPC.

An arctic blast it now pushing into the eastern part of the country and will bring colder than normal temperatures for several days.  This will be the coldest outbreak so far this season.  However, it will be short-lived.


The weather pattern will revert back by next weekend and temperatures will once again be above normal for much of the country.  In fact, January is still forecast to be above normal for much of the country.

Temperature Outlook for January 2012.  Image Credit: NOAA/CPC.

The winter of 2009-2010 was an El Nino year and the winter in South Carolina was much colder than normal.  In fact it was the 4th coldest for Columbia and the 10th coldest for South Carolina.  The next winter (2010-2011) was a La Nina year and it was a strong La Nina.  Yet, it was colder than normal.  Now in the winter of 2011-2012 we have a moderate La Nina and are seeing unseasonably warm weather.


Why?


As I mentioned the wild card is the Arctic Oscillation (AO) which has been in a negative phase the past two winters.  In fact two winters ago it was in the most negative phase in years.  This year the Arctic Oscillation has been in the positive phase.  You can see how the two phases affect temperature in the following figure:

Image credit NOAA/CPC.

Note that the different phases changes the placement of above and below normal temperatures.  It is still cold, but the difference is a matter of degrees.


Thus, it appears that the forecast will remain on track.  This winter will likely be warmer and drier than normal for much of South Carolina.  There will be cold outbreaks, but they are likely to be brief.  The more disconcerting forecast is the one for drier than normal.  This may worsen the drought conditions for the spring planting season.  More on that in a later post.