LIVESTOCK WEATHER JOURNAL VOLUME NO. 1 | ISSUE NO. 1 | MAY 2018 SOUTHWEST U.S. EDITION
SOIL MOISTURE'S DIMINISHING RETURN? Why it's Been So Dry this Winter
TRAVIS AND HIS PAINT BY MIKE CAPRON
LIVESTOCK WEATHER JOURNAL EDITOR Chad McNutt, chadmcnutt@livestockwx.com CHIEF METEOROLOGIST John Feldt, john@bluewateroutlook.com SUBSCRIPTION INFORMATION http://livestockwx.com For questions about subscriptions please send inquiries: info@livestockwx.com Subscription includes 12 issues of the Livestock Weather Journal and monthly Livestock LIVE! webinars OFFICE PO Box 654 Evansville, WY 82636 Email: chadmcnutt@livestockwx.com Ph: 307-797-5656
The Livestock Weather Journal is a Publication of Livestock Wx WWW.LIVESTOCKWX.COM
WELCOME! This is the first issue of the Livestock Weather Journal, which is part of a suite of services provided by Livestock Wx, a company focused on delivering weather and climate information specifically for livestock producers. The Journal will be published monthly and will include a summary of current weather trends and the most recent seasonal forecasts. We will also publish special supplemental issues at key times of the year, such as a calving and lambing season guide, that covers areas of potential active weather. Many people have asked us how we can cover such a rapidly evolving topic like weather in a monthly magazine. The answer, of course, is that the magazine will not focus on daily changes in the weather but the overall trends and what we're seeing a month or three-months out. We will also spend some time explaining what's behind the forecast. For example, in this issue, John Feldt discusses why the three-month precipitation forecast from NOAA is basically a coin toss for much of the country. Finally, as our name implies, the magazine will be devoted to the livestock producer, with an emphasis on the Southwest U.S. More regions will come online as we grow. We would appreciate any and all feedback. You can send feedback directly to me, at the below email. Finally, we would like to thank Mike Capron, who graciously provided the artwork for this issue. Mike also runs the Tales of Texas; a newsletter about Texas, horses, cattle, old friends, and dogs and not necessarily in that order. Subscription Information: http://livestockwx.com Sincerely, Chad McNutt Editor chadmcnutt@livestockwx.com
LIVESTOC
FEBRUARY-APRIL WEATHER TRENDS Large parts of the Southwest U.S. are experiencing severe to exceptional drought impacts. Hardest hit areas are centered near the Texas and Oklahoma Panhandles. TEMPERATURE & PRECIPITATION February and March brought below normal temperatures for much of Kansas and Oklahoma and near normal to above normal for most of Texas and New Mexico (top right image). New Mexico, however, has consistently seen above average temperatures. The period between October 2017 and March 2018 was the 2nd warmest on record. Precipitation was well below normal for the fivestate area of New Mexico, Texas, Oklahoma, and Kansas (bottom image at right). Far West Texas, was also well below normal with values 25% of normal or less. Meanwhile, North and East Texas have been well above average with values 150% of average or more. According to the most recent U.S. Drought Monitor (page 08), 50% of Texas, 99% of New Mexico, 47% of Oklahoma, and 83% of Kansas are considered in drought.
Percent of cattle in Severe Drought or greater (bottom charts, page 8) has been relatively steady since late February with the exception of Kansas, which has seen an increase of about 15 points.
EVAPORATIVE DEMAND Over the last three months, evaporative demand (i.e. the drying power of the atmosphere), has remained strong over most of the Southern Great Plains centered around the Oklahoma-Texas Panhandle. The evaporative demand tool we use is a good indicator of drought and fire-weather risk because it captures the major components that contribute to drying such as temperature, wind speed, and humidity. The evaporative demand data have been a concern and something certainly people on the ground in western Oklahoma have observed first hand with the recent stretch of low humidity, high winds and several large wildfires. We continue to watch these indicators as we move into summer.
Feb-Mar Temperature Anomalies (degree Fahrenheit). Note the cool temps over most of Oklahoma and Kansas.
Feb-Mar Percent of Average Precipitation.
April 19, 2018 U.S. Drought Monitor. Percent area in Drought: NM=99%, KS=83%, TX=50%, & OK=47% 50%
60%
40%
45%
30% 30%
Texas
15%
100%
60%
75%
4/ 19
4/ 05
to
to
4/ 06
3/ 23
to
50%
40% 20%
3/ 09
2/ 23
4/ 06
80%
03 /2 3
4/ 19 to
to 3/ 23
03 /2 3 3/ 09
to
to 2/ 23
4/ 05
0%
3/ 09
0%
Oklahoma
3/ 09
10%
to
20%
Kansas
25%
New Mexico 4/ 10 4/ 03 4/ 06
to
to 3/ 23
3/ 09
to
03 /2 3
3/ 09 to 2/ 23
4/ 06
to
4/ 19
4/ 05 to 3/ 23
3/ 09
to
03 /2 3
3/ 09 to 2/ 23
4/ 05
0% 0%
Percent of Cattle in Severe Drought (D2) or Greater for Texas, Oklahoma, New Mexico, and Kansas from late February to mid-April.
EXCEPTIONAL DROUGHT....AGAIN BY JOHN FELDT
Rhea fire, Dewey County Oklahoma, April 14, 2018. Photo: Oklahoma Forestry Services Large parts of the Southwest U.S. are experiencing severe to exceptional drought impacts. Hardest hit areas are centered near the Texas and Oklahoma Panhandles.
WHY SO WET & DRY? Looking back to the start of winter we see some interesting trends. First, there has been a very unusual and extreme gradient of precipitation from west to east. Drought-stricken areas across western Oklahoma and Texas have received less than ½ inch of rain while eastern areas have received as much as 20 inches. The cutoff between very wet and very dry areas has been quite abrupt and is indicated by the red-dashed line (top image at right). Further east, note the even heavier band of rain in the 20- to 30-inch range just east of the blue-dashed line. Digging a little deeper (Figure 2), the past 90-day departure from normal temperature shows the highly-persistent dome of unusually cold air anchored across the Upper Plains and Midwest
Also note the much milder air over the Southeast U.S.. Boundaries between warm and moist air and cold and dry air are usually action spots where heavy precipitation is most likely. This quasistationary boundary (middle image at right) explains the focus of winter and early spring heavy precipitation and resultant flooding along the Ohio and Lower Mississippi Rivers and their tributaries. Eastern sections of Oklahoma and Texas were near this boundary and within the air mass that could hold enhanced amounts of atmospheric moisture. Thus, a lot more rain. On the other hand, western sections of Oklahoma and Texas were within a colder, drier, and more stable air mass - much less likely for precipitation.
WHY SO COLD? So, the unusually persistent cold air played a key role in setting up the boundary that helped align the focus for a lot of rain or not much at all. But, why was it so cold over the Northern Plains and Upper Midwest for much of the winter and now well into the spring?
We need to look at the jet stream alignment, and especially the infamous Polar Vortex. A Polar Vortex is an area of low pressure that is usually anchored, with its associated very cold air, over arctic regions. When the PV is strong, a strong circulation tends to confine the cold air within arctic areas. On the other hand, when the Polar Vortex is weak, cold air often is displaced further south. This winter was dominated by a weak Polar Vortex which allowed cold arctic air to settle unusually far south and helped set up the temperature contrasts which lead to strong temperature and precipitation anomalies. But what is behind this persist jet stream pattern - and when might it change? To assess the mechanics behind the alignment of the jet stream, we need to review sea surface temperature and arctic ice anomalies.
LACK OF ARCTIC SEA ICE Recent research points to a possible link between reduction of arctic sea ice and the unusually cold weather and frequent winter storms over the Northeast U.S. this winter. The theory goes that a warming planet has warmer ocean water, leading to breaks in arctic sea ice. This increase in open water increases evaporation which in turns allows for increased snow downstream. This extensive snow "reservoir" serves as a season-long source for cold air, which is then transported southward into the U.S. Arctic sea ice reached record-low levels this past winter.
180-Day Observed Precipitation
180-Day Temperature Anomalies
Typical La Niña pattern for the U.S.
IMPORTANT ROLE OF LA NIÑA Now that we have some understanding of the mechanics behind the unusually dry weather over the South Central and Southwest U.S let's consider what might lie ahead. According to Australian Bureau of Meteorology, the recent La Niña has ended. All climate models now forecast "neutral" conditions within the next month and continuing through the summer months. I suspect we have already experienced peak La Niñarelated impacts with negligible future influence by June.
DIGGING OUT OF AN EXCEPTIONAL DROUGHT Realistically, even with a return to more normal weather, it would take time to eliminate drought impacts from the hardest-hit areas. It would take approximately 3- to 6-additional inches of rainfall to significantly alleviate the most extreme drought impacts. As we get into May and June, however, we are entering the peak rainfall period for much of Texas and Oklahoma. The extremely dry soils, though could come into play. At least initially, such significantly-dry soils will result in reduced evaporation and degraded vegetation will reduce evapotranspiration. In turn, this could lead towards reduced precipitation (i.e., negative feedback loop).
WHAT'S THE OUTLOOK? There are several factors pointing towards a slow improvement in severe rainfall deficits and drought impacts over the next several months. First, La Niña will have less and less of an impact. Also, summertime tends to have its own climatology, often of more significance than the more subtle La Niña pattern. On the other hand, we really don't completely understand all the factors that have come into play regarding the severe drought.
Furthermore, heading into summer, dry soils could limit precipitation and the heat of summer over the Southwest U.S. is not an ideal time for soil moisture recovery. I suspect that drought impacts will persist for several more months, but that there could be a slow improvement by fall. Take a look at the Seasonal Outlook section for a more detailed insight into the outlook for May.
IVESTOCK W AT ER LIVE.� U ,\1-11 IE I
I
H'
R
MAY-JUNE-JULY SEASONAL OUTLOOK BY JOHN FELDT
LOOKING AHEAD TO THE SUMMER NOAA's long-lead outlook for the upcoming months of May, June, and July (next page, top image) call for the return of above-normal temperatures across much of the nation. The 3-month outlook closely aligns with summer heat trends since 1970. For example, summer has been getting hotter over the entire nation with the exception of the North Central U.S.
PRECIPITATION The outlook for rainfall (next page, bottom image) has large parts of the nation classified as "EC" (unshaded) meaning there is an equal chance for either normal, below normal, or above normal rainfall, otherwise known as a toss-up. The demise of La Niña points towards what's considered a neutral summer.
In fact, summertime weather is often influenced by smaller-scale (local or regional) weather systems and not the more widespread systems, often influenced by large scale phenomena like La Niña or El Niño, typical during the winter months. A neutral summer will likely result in a lot of regional rainfall variability making a forecast quite difficult.
DROUGHT OUTLOOK Persistently-severe drought impacts are being observed over much of the Southwest and South Central U.S., including parched soils, record-low stream flow, and very high wildfire risk. As La Niña impacts gradually wane, precipitation is likely to slowly trend back towards historical normal levels. This is a reason why the seasonal drought outlook calls for drought impacts to remain but improve over parts of Kansas, Oklahoma, Texas, and smaller portions of surrounding states. .
Temperature Outlook for May-June-July. The temperature outlook reflects summer temperature trends over the last several decades. The largest probabilities for above normal (A) temperatures reach or exceed 60% for a large part of the Southwest U.S.
Precipitation Outlook for May-June-July. The lack of a strong forecast (i.e., most of the country is "EC") reflects the fact that summertime weather is often influenced by local or regional weather systems and not the more widespread systems that can be influenced by a phenomena like La NiĂąa.
SOIL MOISTURE'S DIMINISHING RETURNS IN THE SOUTHERN PLAINS BY CHAD MCNUTT There's a memorable passage at the beginning of Elmer Kelton's book that provides some context for this article. The book is The Time it Never Rained, and it is about the 1950's drought in Texas: -Why worry they said. It would rain this fall. It always had. But it didn't. And many a boy would become a man before the land was green again.-
THE CREEPING PHENOMENA IDrought can be "insidious", meaning that it has a tendency to sneak up on you. Of course - it can also last for years and sometimes it's hard to know when you're even out of a drought. Kelly Redmond, a unique and very knowledgeable climatologist, once said it was possible to have a short-term drought in the middle of a longer-term wet phase inside a much longer dry period.
Since the new millennium arrived, it seems Texas and Oklahoma have had a lot of dry periods interrupted by some extremely wet years (2015 comes to mind). But mostly, it has been dry. Many will say, "that's how it goes in the Southern Plains", but the frequency of the dry periods and the extreme temperatures has got us thinking what sort of long-term impact these events have had on rangelands and cropland. To add a bit more perspective to this question, on the next page is a map that shows the number of weeks each county in Texas and Oklahoma have been in Exceptional Drought (i.e., D4) since the beginning of the 2005. Exceptional Drought is the highest drought category used in the Drought Monitor. Statistically, it should occur about 2% of the time or about once every 50 years. Several counties have been in Exceptional Drought for over 200 weeks, or about 30% of the time since 2005. I would suggest that it is exceptional alright, but unfortunately, not in the way exceptional should mean.
Jac
No. of Weeks in Exceptional Drought 202
Wilbarger County, TX
193
Wichita County, TX
192
Tillman County, OK
181 169 166
Top 10 Texas and Oklahoma Counties Since 2005, the Rolling Plains of Texas and Oklahoma have been in Exceptional Drought more than any other region in the U.S. Exceptional Drought is the highest drought category in the U.S. Drought Monitor. Wilbarger, Wichita, and Tillman Counties, in particular, have spent more time in Exceptional Drought--equivalent to almost 4 years--than the drought stricken Central Valley in California. The area includes Lawton, Oklahoma and Wichita Falls, Texas, communities that have struggled in recent years with water supply shortages. Wichita Falls most famously considering using wastewater as a source of municipal water supply in 2014.
166 165 151
144
Baylor County, TX
Jackson County, OK
Greer County, OK
Foard County, TX
Knox County, TX
Archer County, TX
Harmon County, OK
Jac
DROUGHT IMPACTS NOT WHAT WE EXPECT Gary McManus, the State Climatologist of Oklahoma, is one of the experts primarily tracking drought for the state. Gary communicates with a large network of farmers and ranchers, along with groups like county Extension agents and USDA's Farm Service Agency. Gary takes this input and provides it weekly to the U.S. Drought Monitor. Over the last few years, he has noticed that traditional climate and meteorological indictors used to track drought do not always correspond well to the impacts that farmers and ranchers are seeing on the ground. I contacted Gary because we have been hearing about this issue and I was curious to know if it was possible the extreme, and somewhat consecutive droughts, have had a lasting influence in Oklahoma. The issue could be something more fundamental in the basic function of grasslands and croplands. In other words, these droughts have been so extreme, and their impacts have been lingering for so long, that it has had subtle and lasting impacts to the ecology of the system. I specifically asked Gary if he thought the intensity and duration of the droughts could have affected the structure and function of the soils in Oklahoma and therefore key soil qualities like the water holding capacity. Gary couldn't say if it was something as fundamental as changes in the soil, but he noted that "ag producers are saying the droughts are more intense than what the indicators are saying". Gary further explained that he is hearing (from some producers) that they have been going into drought much sooner than what he would expect and that when they do get some moisture, it is not lasting as long. In Harper County, Oklahoma, where Gary is originally from, he has noticed the water table still has not fully recovered since the 2010 drought. He noted that spring fed ponds used to be reliable, and now, even after good rains, the ponds are going dry relatively quickly.
While the difference between how we monitor for drought and the impacts we see on the ground can be significant, it is something an old drought hand like Gary takes into account. That's why he has cultivated a fairly vast network of people around the state that can help him ground-truth the monitoring data he is seeing. By the way, these are the same data that will be used in the U.S. Drought Monitor to define its drought categories and ultimately assistance programs like the Livestock Forage Disaster Program. Gary said if he sees a disconnect between the data and impacts, it's a warning sign that he needs to look at other indicators and find out why things aren't matching up.
DROUGHT AND EROSION On Gary's recommendation, I contacted Dr. Tyson Ochsner, who is an Associate Professor and soil scientist from Oklahoma State University. I asked Dr. Ochsner what he thought about the droughts in Oklahoma and Texas and whether they could still be having an impact, and in particular, a lasting impact on the soils in Oklahoma. He responded, "I don't really have the data but can image how it might happen". Dr. Ochsner explained that 2011 was a brutal year and that a lot of the pasture and cropland were hit hard. Without vegetative cover and with little residue being returned to the soils, it is likely these harsh droughts have caused a loss of topsoil, increased soil compaction, and as a consequence, reduced water infiltration and reduced water availability capacity of the soils. One stark example of this issue is shown in the dust storm that shut down I-35 in October 2012. Dr. Ochsner explained that the dust wasn't just coming from the cropland, but the range was also contributing to the massive amount of dust being generated due to a lack of vegetative cover. He stated, "If we lose topsoil to wind and or water erosion, we are going to reduce available water capacity".
SOIL MOISTURE continued from page 17 Dr. Ochsner explained a rule of thumb in Oklahoma has always been that you're never more than two weeks away from a drought. Oklahoma soils do not have a large water storage capacity to start with. He stated, "Best case scenario, take the top 32 inches of soil and that might store at most 8-9 inches of water. [Then, you] Get into peak of summer with evapotranspiration rates approaching half inch a day. That doesn't give you many days of actual supply." We discussed that it's possible the erosion of topsoil from the successive droughts since 2005 may have reduced that two-week rule of thumb to something like maybe 10 or 13 days. That could be a big deal and one of the reasons we are seeing a disparity between our indicators and impacts on the ground. Bottom line, there's a chance we don't have the same amount of reservoir capacity in the soils we did prior to all these drought events. Dr. Ochsner explained monitoring soil moisture gets to the heart of the matter better than some of the precipitation and temperaturebased indicators that are often used to track drought. Oklahoma, as it turns out, is one of the best monitored states in terms of soil moisture thanks to the Oklahoma Mesonet program. The Mesonet has 120 automated environmental monitoring stations across the state.
1-day Average Percent Plant Available Water map. Lots more information on weather and climate trends for Oklahoma can be found at the Oklahoma Mesonet website: http://www.mesonet. org/index.php
Dr. Ochsner suggested a good map for producers to look at is the Percent Plant Available Water map (shown below). If the percentage of plant available water drops below 50%, active vegetation will typically experience water stress. As of this writing, several areas in western Oklahoma (Roger Mills and Woodward Counties) and the Panhandle (Texas County) are experiencing values significantly below 50%. Dr. Ochsner told me another story about the 2010 drought. In 2011, the drought had really started to intensify; however, in 2012, he said, "we were starting to see some recovery thanks to above average precipitation in the spring". Due to the warm and wet conditions, though, the growing season started about a month earlier that year. In May, he started noticing the soil moisture was down again and that the drought could be creeping back. Other indicators, however, were not showing signs of trouble. "By the first of June, it became evident that drought was on us again". By late Julyearly August, there was several major wildfires that were being exacerbated, in part, by the dry fuels from the early growing season. We discussed again, that many of the indicators that were developed to track drought were never designed to capture something so nuanced as an early growing season and what impact it might have on the lack of soil moisture later in the summer.
IMPROVE MONITORING The drought monitoring community is really good at looking at how climate and weather drive droughts but are less adept at understanding all the ecological interactions and feedbacks. There is recognition, however, that we need to get better with how drought is monitored and particular how we monitor things, such as soil. As Kelly Redmond would remind us, we should understand the difference between short-term drought and an event that is much longer with less obvious impacts. I am happy to report Dr. Ochsner and I left our conversation with him telling me that he and colleges at OSU have soil samples from several sites across the state taken before the 2005 drought and will be comparing them to samples taken more recently to look at this question of changes in soil structure and composition. Right now, though, it is of little consolation, as we are staring down yet another drought that may or may not intensify this summer. The Rhea Fire has burned over 250,000 acres and caused two fatalities. The April 20th Cattle on Feed Report just came out, and it shows the feedlot cattle inventories continue to increase. The April release is the second highest reported for April since reporting began in 1996. The highest? April 2006, anyone remember what was going on in 2006?
Livestock Wx PO Box 654 Evansville, WY 82636