Warm and wet weather continues

Taken from the UGA CASE blog

Outlooks for the next two weeks indicate that our warmer and wetter than normal weather is likely to continue for the next couple of weeks.   The Climate Prediction Center is indicating that an area of particularly heavy rains may occur in far northeastern Georgia into South Carolina and western North Carolina on May 29-30.


In addition, some long-range forecast models indicate that a tropical depression has a chance of developing in the western Caribbean Sea early in June, with the potential to track over the Southeast if it does develop.  Of course, this is a long way away, but as we enter the Atlantic tropical season, the chances a tropical storm could form start to ramp up.  More on tropical weather on June 1, the start of the Atlantic hurricane season.  Meanwhile, major hurricane Amanda has formed in the eastern Pacific Ocean but is staying out to sea.  This is the earliest that a major hurricane has developed in this region in recorded history.

Heat Awareness Day opens the Memorial Day weekend

Taken from the CASE blog. See the original article here.

May 23 is Heat Awareness Day for the National Weather Service.  Memorial Day marks the unofficial start of summer for many people, and heat is one of the major killers of people and animals in summer months.  If you would like to learn more about the impacts of heat and how to prevent heat injury, click here.

Meanwhile, the next few days show the possibility of rain across most
of the Southeast with the exception of southern Alabama.  The rain should move into most of the area on Sunday afternoon (May 25) and continue into Tuesday (May 27) in the form of scattered showers and thundershowers.

El Nino may impact weather this summer

Original article taken from May Peanut Pointers and can be found here

The warm pool of water in the equatorial Pacific Ocean continues to move eastward, increasing chances for an El Nino to develop later this summer into fall.  In winter, El Nino causes wet and cool conditions in south Georgia as the subtropical jet stream shifts right over the state, bringing clouds and plentiful precipitation with it.  El Nino impacts in summer are more subtle and the summer weather patterns tend to be dominated by local storms rather than large-scale weather patterns.

However, we know that Atlantic hurricanes are less likely in El Nino autumns, which could be good news for farmers trying to get into their fields in fall to harvest peanuts, since with fewer storms we may experience drier conditions.   By comparison, tropical activity in the eastern Pacific Ocean is enhanced.  And sure enough, there is already some unsettled weather occurring there which might turn into the earliest eastern Pacific named storm ever if it pulls itself together.

Meanwhile, the wet spring, coupled with recurring cold fronts, have kept soil conditions far from ideal for planting.  With the warm and sunny weather this past week, however, farmers should be taking advantage of better conditions to get out into the fields and get things done.

Looking ahead, warmer and wetter than usual conditions are predicted to return May 12-16, with near normal conditions May 16-20.  As a whole, May is expected to be near normal in temperature and precipitation, and the summer has an increased chance of warmer than normal temperatures based on long-term trends.  There is no skill in predicting summer rainfall this year and there are equal chances for near, above and below normal precipitation.

(Reprinted from Peanut Pointers newsletter for May)

Easy web site to plot climate trends

Article retrieved from CASE

CASE image 1The National Climatic Data Center (NCDC) is the official Federal archive of weather and climate data for the US, and they have data for many other countries as well.  One of their most useful tools is their new “Climate at a Glance” web site, which allows you to plot trends in climate variables like temperature, precipitation, and drought indices for any part of the US.  The web site includes a link to a map of climate divisions for the US so you can pick your region.

Here is the website address:  http://www.ncdc.noaa.gov/cag/time-series/us

Climate Outlook for 2014 Growing Season and Winter 2014-15

Pam Knox, UGA Climatologist

Taken from Climate and Agriculture in the Southeast (CASE)

Following a very wet 2013, this year has gotten off to a drier than usual start, although generally soil moisture has been very good until recently. In the last few weeks, abnormally dry conditions have started to creep into the mountains in northeast Georgia as well as scattered locations in the west central and southwest parts of the state.  However, a major drought is not expected to develop this growing season.

Short-term forecasts out to two weeks indicate that some dryness may continue in southern Georgia but north Georgia is likely to be wetter. In the one to three month period that includes April through June, there are equal chances for below, near, and above normal rainfall, since accurate predictions are very hard in neutral conditions when no El Nino or La Nina are occurring. However, following recent climate trends, temperatures have an increased chance of above normal conditions for the next few months.

NOAA has now issued an El Nino watch for the potential development of an El Nino in the eastern Pacific Ocean by mid to late summer. When an El Nino occurs, we commonly see wet and cool conditions in south Georgia associated with the persistent presence of a subtropical jet stream above the earth’s surface which directs weather systems right across Georgia.

At this time, NOAA is predicting a 50 percent chance of an El Nino developing by midsummer.  If one does occur, then we can expect next winter to be cooler and wetter than normal in 2014-2015. Some scientists believe that this is likely to be a stronger than usual El Nino based on current ocean temperatures. If that happens, the cool and wet conditions will extend throughout Georgia instead of just affecting the southern part of the state.

One impact of El Nino on Georgia’s climate is a reduction in the number of hurricanes in the Atlantic Ocean. However, even in a quiet season, a single direct hit by a hurricane or tropical storm can cause significant damage to the area it passes over. Most other effects of El Nino are seen in the winter when the El Nino is strongest.

Other impacts from El Nino include excessive cloudiness, which reduces solar radiation and increases drying times for hay as well as enhancing the development of fungal diseases. Low-lying areas are likely to be soggy and hard to work due to the persistent rain. Cooler temperatures and high humidity may also affect the development of pecans and Vidalia onions, reducing pecan yields as well as the average size of the onions. In general, El Nino winters are not associated with unusually late frost dates, however.  Runoff may also increase, leading to increased erosion or movement of surface applications into streams.

You can find more information about the impacts of El Nino on climate patterns and crop yields at www.agroclimate.org.

Winter near average for Georgia in spite of some cold mornings

Pam Knox serves as University of Georgia Agricultural Climatologist with UGA Department of Crop and Soil Science

Released March 20, 2014. See original article here.

Despite some bone-chilling days with single digit lows, Georgia’s winter was about average in both temperature and precipitation.

This winter, which climatologists define as Dec. 1 to Feb. 28, was actually the 57th coldest out of the past 119 winter seasons. This means that 56 years were colder than the 2013-2014 winter season and 62 were warmer. This places it just about right in the middle.

Georgia’s winter precipitation was ranked 67th out of 119 years, which means that 66 years were drier and 52 were wetter.

The near-normal average temperatures this year were the result of a combination of the scattered days with above normal or record-high temperatures that some parts of the state experienced and the periods of frigid weather that brought very cold temperatures to northern parts of the state.

This was the first time that such cold temperatures have been observed in Georgia since the winter of 1995-1996. Periods of very cold weather were more frequent in the 20th century than in recent years.

The winter conditions provided plentiful chill hours for peaches across Georgia. The fruit should be in great shape as long as a late frost after blooming does not hurt the development of the peaches this spring.

Cold conditions have reduced the average size of Vidalia onions this year as well as cut stands by up to 25 percent. Overall, however, supplies are considered to be very good.

Lawns in north Georgia with warm-season grasses like centipede may see some damage due to some of the extreme low temperatures.

Some insect pests may have been cut back by the cold weather, but many are well adapted to shelter in the coldest conditions and the rapid swings in temperature may not have provided long enough cold conditions to cause a significant dent in their populations.

Other impacts from this winter’s weather include the damage to timber in the mid-February ice storm. The ice caused widespread power outages and tree damage to north central and eastern Georgia, particularly in the Augusta area.

While the state is starting to shake off the chill of the last few months, Georgians can expect cooler and wetter than normal conditions across Georgia for the next two weeks, based on predictions from the Climate Prediction Center, NOAA.

Gardeners should also remember that a late frost is still possible and perhaps more likely than in other years because the state is in a neutral weather pattern — one not affected by La Nina or El Nino.

Landscapes may be more at risk of a late frost this year

Merritt Melancon is a news editor with the UGA College of Agricultural and Environmental Sciences

The northern and southern halves of the state vary slightly, but Georgia’s last frost typically falls between mid March and mid April. On some years the last frost has hit as late as May. University of Georgia Extension climatologist Pam Knox believes the current neutral weather pattern — one not affected by La Nina or El Nino — could put Georgia at greater risk for one of these rogue late frosts.

There’s no way for a gardener to predict or stop a late frost from hitting after they’ve put in transplants or started counting sprouts, but they can be prepared, said Paul Thomas, a UGA Extension horticulturist. Since no one knows when a frosty night might hit, gardeners should have a frost tool kit and game plan ready.

“Buying or collecting frost reduction materials prior to the frost and pre-positioning them close to the plants you want to protect is very important,” Thomas said.

One of the most effective ways to shield plants from frost is to cover them with any of a wide variety of materials, from high quality frost–reduction fabric, to blankets and sheets, to newspapers, baskets and straw.

For small shrubs such as Gardenia, a supply of old comforters or heavy blankets — maybe purchased from a local thrift store — will allow you to protect your plants from that first frost without spending much money. Covering plants with a heavier blanket will protect them more than if they’re covered with a simple sheet, Thomas said.

In addition to blankets, simple mulches — like dead leaves or grain straw — are some of the best materials for protecting small plants and flowers. For smaller plants such as young vegetable starts, lighter weight material like pine straw works great if enough is placed over the plants.

Gardeners can completely bury their newly flowering shrubs or tender garden seedlings in either leaves or straw, and then uncover them after the weather warms back up. The flowers and seedlings will be fine, he said.

Never use plastic sheeting to cover plants because plastic can trap too much heat. When the day starts to warm up, the plants can actually cook or scorch under the covering. “By 10:00 a.m. you can have significant damage to grass and young plants due to how quickly it can heat up under that plastic,” Thomas said.

It’s best to cover plants before sunset to retain some of the heat that is trapped in the soil and remove the coverings in the morning just after sunrise to prevent the plants from being scorched. The exception would be if it’s cloudy, snowing or icy.

Thomas also recommends having a collection of wooden garden stakes on hand. Place the stakes throughout your vegetable patch in order to suspend blankets over tender seedlings or delicate flowers. The stakes will prevent snow or rain soaked blankets from crushing your plants, Thomas said.

Insects and Cold Weather

Elmer Gray, University of Georgia, Entomology Department

With this winter’s unusually cold temperatures, the question of how these conditions affect insects is sure to arise. It is of little surprise that our native insects can usually withstand significant cold spells, particularly those insects that occur in the heart of winter. Insect fossils indicate that some forms of insects have been in existence for over 300 million years. As a result of their long history and widespread occurrence, insects are highly adaptable and routinely exist and thrive, despite extreme weather conditions. Vast regions of the northern-most latitudes are well known for their extraordinary mosquito and blackfly populations despite having extremely cold winter conditions.

The question then arises, how do insects survive such conditions? In short, insects survive in cold temperatures by adapting. Some insects, such as the Monarch Butterfly migrate to warmer areas. However, most insects use other techniques to survive the cold.

Vector of West Nile Virus

In temperate regions like Georgia, the shortening day length during the fall stimulates insects to prepare for the inevitable winter that follows. As a result, many insects overwinter in a particular life stage, such as eggs or larvae. Many mosquitoes overwinter in the egg stage, such as our common urban pest the Asian Tiger mosquito (Aedes albopictus), waiting for warmer temperatures and sufficient water levels to hatch in the spring. Another technique is to take advantage of protected areas, as do adult Culex mosquitoes overwintering in the underground storm drain systems. Other insects overwinter as larvae or pupae in the soil, protected from the most extreme temperatures. However, this still doesn’t answer how insects survive freezing temperatures, only to become active as warmer temperatures return.

All insects have a preferred range of temperatures at which they thrive. As the temperature drops below this range the insects become less active until they eventually cannot move. A gradual decline in temperatures, coupled with a shortening day length, serves to prepare an insect to tolerate freezing temperatures. Several factors are important to this tolerance.

The primary thing that an insect has to avoid is the formation ice crystals within their body. Ice crystals commonly form around some type of nucleus. As a result, overwintering insects commonly stop feeding so as to not have food material in their gut where ice crystals can form. This reduction in feeding will also result in a reduction in water intake.

A degree of desiccation increases the concentration of electrolytes in the insect hemolymph (blood) and tissues. In addition, insects that can tolerate the coldest of temperatures often convert glycogen to glycerol. These electrolytes and glycerol create a type of insect antifreeze. This will lower the freezing point of the insect to well below freezing, a condition described as supercooling. When this occurs, the insect can withstand extremely cold temperatures for extended periods.

However, at some point insects will suffer increased mortality, possibly due to desiccation, toxicity or starvation. Nevertheless, insects are well adapted to survive freezing temperatures, especially after a few 100 million years to perfect their systems. It is generally assumed that introduced pest insects from sub- and tropical areas would be more susceptible to extended cold spells, but depending on their ability to find local refuges and their numbers and adaptability, they likely will remain viable and persist as pests as well.

In summary, entomologists don’t expect the cold winter to have a significant impact on insect populations this spring. Local conditions related to moisture and overall seasonal temperatures (early spring/late spring) will play a much more important role in insect numbers as we move from winter to summer and prepare for the insects that will be sure to follow.

Georgia lawns may show cold damage this spring

Sharon Dowdy is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.

Lawns in Metro Atlanta and north Georgia counties covered in warm-season grasses like centipedegrass or St. Augustinegrass will likely show signs of cold damage this spring as a result of the recent snow and ice storms, says University of Georgia Extension turfgrass specialist Clint Waltz.

“The temperatures were down in the single digits for 60 hours, so we are likely to see some losses, especially in common centipedegrass. Also, there is a lot of St. Augustinegrass in Atlanta, especially in shady areas. You’ll be able to see (the cold damage) when it doesn’t green up this spring,” said Waltz, a scientist in the UGA College of Agricultural and Environmental Sciences. “There’s still a little bit of a question mark about lawns in south Georgia.”

No protection

Homeowners and landscapers caring for common centipedegrass should not “be surprised to see it come out thin and spotty,” this spring he said. “It’s going to take a some work to get it back into shape over the summer growing season.”

Centipedegrass and St. Augustinegrass have no below ground rhizomes. They grow above the ground through stolons, or runners. This makes recovery and regrowth of these species more difficult.

Waltz says homeowners can choose to turn the cold damage into an opportunity for change.

Tifblair centipede - Georgia Integrated Cultivar Release System
Tifblair centipede – Georgia Integrated Cultivar Release System

“With the potential loss of some centipedegrass and St. Augustinegrass, this would be the year to consider converting your lawn to something more cold hardy like zoysiagrass. Then you won’t have to worry about every ninth year when we get a very cold winter,” he said.

For those who decide to change to a new turfgrass variety, Waltz recommends cold hardy UGA-bred TifBlair centipedegrass or a zoysiagrass variety. “Zoysiagrass is pretty cold hardy species. I’d be surprised to see it damaged,” Waltz said.

Time will tell for bermudagrass

Waltz is unsure what’s ahead for homeowners with bermudagrass lawns. “If you could tell me what the weather is going to be like, I can tell you how the grass is likely to recover,” he said. “If the weather warms up and stays warm, then bermudagrass will probably be fine, but if we get another snow or if it drops down into the teens after we have 30 to 50 percent green-up, the cold snap will cause the grass to go dormant, and it is possible it won’t green-up again.”

Warm temperatures tell the grass it’s springtime, but when temperatures drop, the plant doesn’t know how to respond, he said. If early April brings 65 degree temperatures, the grass will begin to sprout. If a late frost occurs, the new “succulent grass tissue” can be lost, Waltz said.

“Tifway is not a particularly cold hardy cultivar of bermudagrass. TifSport, TifGrand and Patriot are and will likely do fine,” Waltz said.

Homeowners can help their bermudagrass lawn by doing nothing.

“After the cold we’ve had, there is really nothing you can do. Just let (the lawn) green-up on its own and don’t fertilize it,” he said.

Don’t listen to the commercials

Ignore television commercials, radio and print ads that advise fertilizing lawns.

“Don’t listen to the marketing when they say ‘Now is the time to fertilize,'” Waltz said. “When we get into March Madness and you start hearing the personalities that know sports but don’t know about turfgrass tell you to fertilize your lawn, disregard all that.

“Clint Waltz is telling you that when it comes to warm-season grasses hold off on that first nitrogen application until late April or early May,” he said.

Bermudagrass, centipedegrass, St. Augustinegrass and Zoysiagrass should be fertilized when the soil temperature is consistently 65 degrees and rising at a 4-inch soil depth, he added. Usually this is late April or early May in Metro Atlanta.

For more on turfgrasses in Georgia, see the UGA Extension website www.GeorgiaTurf.com.