October 25, 2018 Drought and Agriculture Report – Not Wet Where it is Dry

Written by Sig Silber

Updated at 8:20 PM EDT October 26, 2018 to reflect updated MJO related Week 3 – 4 Forecast

Not much improvement this week with respect to drought but we expect additional improvement soon. In fact our Drought Report may soon focus more on floods and heavy snows than drought. But more versus less precipitation and more versus less evaporation are the deviations from climatology that happen on a more or less regular basis. Those who assume a period of more or less drought or more or less floods is the New Normal mostly mistake the variability in weather that is part of nature. That is not to say that our climate is stationary – variability, much of which has patterns that are to some extent predictable, is the norm. Understanding the patterns can lead to improved responses to weather and climate variability.

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How to put the current drought into perspective?

This is a tool for doing streamflow comparisons.

Not sure if the example shown  was selected for a purpose. Was July of 1934 the worst ever?

A  recent event that provided a lot of moisture

This report is now organized as follows:

1. Present Drought Conditions
2. Last Week’s Weather
3. Information from our Weekly Weather Column (the forecast maps auto-update) and combined with brief commentary from me provides a forecast which I attempt to interpret re the likely change in drought conditions
4. U.S. Crop Information
5. International Crop Information and related weather
6. Prior month’s weather and month-to-date weather excluding the prior week when I have that information. Drought is based on cumulative deficits.
7. A science theme if we have one.
8. Reference Information. (This includes a lot of information on reservoirs that we are not focusing on this week)

1. Present Drought Conditions

The U.S. Drought Monitor is a comprehensive way of understanding the drought situation for the U.S. It is issued every Thursday and reflects the conditions as of the prior Tuesday. Drought is defined as a moisture deficit bad enough to have social, environmental or economic effects. Thus, more factors than recent precipitation are considered and more information on how it is done is found at the end of this report.

Below is the same map but just CONUS and with statistics and below that map I have provided a cut-out of the statistics which I think you can click on to enlarge.

The graphic below shows the one-week change in drought intensity. Yellow is bad. Green is good.

This pair of maps might make it easier to get a general idea of what is happening in the worst part of the drought area.

Last Week	This Week

This map which covers the West may be useful also.

Now we show the week to week change information by region. The yellow is where the drought has been upgraded. The green is where the level of drought has been downgraded.

No Change

No Change

Slight Improvement

Slight Improvement

Some Deterioration

Southern Improvement

Some may find this way of looking at things useful and I hope these graphics are not too small to read. I did not make them so you could click on them individually but you can click on the whole graphic and it may enlarge. But I think you get the picture. It has been a rapid onset and hopefully it’s demise will also be fairly rapid. When you read these graphics remember that the older graphics are not the drought conditions that existed then but the change from then until now. 

Some might find this animation of twelve weeks of change useful;

Here is the discussion which was issued with the Drought Monitor today.

This Week’s Drought Summary

Outside of additional heavy rain across the southcentral United States, conditions were generally quiet across the Nation. The break from the recent active weather pattern led to a quiet week in the U.S. Drought Monitor, with changes mostly confined to the South. While lingering wetness further reduced or eliminated drought from the Four Corners into Texas, short-term dryness was developing over parts of the Southeast. Note: the weekly drought analysis incorporates rain that has fallen through 12z Tuesday (8 a.m., EDT); any precipitation that falls after the data cutoff will be included in the following week’s assessment. Consequently, the heavy rain — associated in part with the remnants of Eastern Pacific Hurricane Willa — that has impacted (or will impact) much of the southern and eastern U.S. through the weekend will be accounted for next week.

Northeast

Drought conditions were largely unchanged during the period as the region awaits the weekend Nor’easter, though another storm was bringing rain and inland snow to New England after the Tuesday-morning data cutoff. Small additional reductions to Abnormal Dryness (D0) and Moderate Drought (D1) were done in Maine, incorporating updated precipitation data and feedback from local experts in the field. With each passing precipitation event, the drought impacts continue to diminish, and are now mostly reflected in lower-than-normal streamflows and groundwater supplies in the region’s lingering drought areas.

Southeast

Showers in northwestern portions of the region contrasted with generally dry conditions elsewhere. For much of the period (through 12z Tuesday, 8 a.m., EDT), showers (locally more than an inch) were mainly confined from northern Alabama into the southern Appalachians. Rain totals were not sufficient to afford relief from Abnormal Dryness (D0) but nevertheless mitigated concerns over developing short-term deficits, particularly in southcentral Tennessee. Following last week’s sweeping reductions in drought from the Florida Panhandle into northcentral Georgia, modest increases to D0 in southeastern Georgia and northcentral Alabama were coincident with 60-day rainfall below 70 percent of normal (locally less than 50 percent). However, drought experts (local and regional) are awaiting the end-of-week storm and its resultant impacts, which will be incorporated into next week’s assessment.

South

Another round of moderate to heavy rain was responsible for additional widespread reductions of drought intensity and coverage. Much of central and eastern Texas was doused with 2 to 6 inches of rain, with amounts locally more than 10 inches from the eastern Edwards Plateau to College Station. This rain fell on top of downpours from the preceding two weeks, pushing 30-day totals to locally more than 20 inches. As a result, Texas drought was confined to a relatively small area east-southeast of Amarillo at the end of the period, where 365-day precipitation totals remained between 60 and 75 percent of normal. Farther east, moderate to heavy showers (1-5 inches, locally more) also led to additional reduction to the lingering Abnormal Dryness (D0) in northern Louisiana and southern Arkansas. Smaller reductions to D0 and D1 were made in southwestern and northeastern Oklahoma, coincident with locales where another round of rain pushed 180-day precipitation totals to near- or above-normal levels. In contrast, small expansion of D0 was made in northeast Oklahoma in locales which largely missed the recent rain and have subsequently seen deficits at or beyond 6 months begin to climb.

Midwest

While much of the Midwest remained free of drought, rain in southern portions of the region eased lingering dryness. In particular, rain totaling locally more than an inch — on top of a wet October to date — led to the removal of Moderate Drought (D1) in southwestern Missouri. The rest of the Midwestern Abnormal Dryness (D0) and D1 areas were dry but chilly, with temperatures averaging up to 10°F below normal. While the recent dry weather has begun to raise some concerns over short-term moisture deficits, the drier weather has aided corn and soybean harvest efforts overall.

High Plains

After recent improvements to the region’s lingering drought areas, conditions were unchanged during the past week. Mostly dry weather prevailed, with temperatures averaging up to 5°F above normal on the northern Plains. Across the region, recent rain and snow have helped to recharge water reserves and soil moisture while aiding pasture recovery and improving prospects for winter wheat establishment. However, significant longer-term moisture shortages linger in the Moderate to Extreme Drought areas (D1-D3), with precipitation over the past 365 days totaling locally less than 60 percent of normal.

West

A respite between storms afforded local experts an opportunity for further assessment of the current drought situation, with locally heavy precipitation arriving in southern portions of the region after the drought monitoring period. Precipitation up to the data cutoff (12z Tuesday, or 6 a.m., MDT) generally totaled less than an inch (liquid equivalent), though amounts were locally higher in the Four Corners Region and immediate environs. Modest reductions were made in eastern New Mexico to Abnormal Dryness (D0), Moderate Drought (D1), and Severe Drought (D2), where this week’s rain pushed 6-month precipitation totals to near- to above-normal levels. Farther west in southern California and western Arizona, discussion with local experts as well as a detailed analysis of longer-term precipitation deficits and satellite-derived vegetation health data supported trimming the coverage of D2 and D3 (Severe to Extreme Drought); in particular, 24-month precipitation has climbed to near-normal levels along the California-Arizona border. In contrast, dry weather persisted in Northwestern drought areas, where 180-day precipitation has tallied a meager 20 to 50 percent of normal. Rain and snow will be needed soon to prevent an expansion and intensification of drought across the Northwest. Conversely, another moisture-laden storm was bringing moderate to heavy rain and mountain snow to the lower Four Corners after the end of the monitoring period.

Alaska, Hawaii, and Puerto Rico

Drought conditions remained unchanged in Alaska, though the arrival of a wet weather pattern brought beneficial rain (2-4 inches, locally more) to the state’s southeastern drought areas. Despite this week’s ran and mountain snow, 180-day precipitation remained at or below 60 percent of normal; these longer-term departures highlight the need for sustained rain and snow to cut into the drought. Hawaii remained free of Abnormal Dryness (D0) or drought. In Puerto Rico, heavy showers (2-4 inches) continued, though the rain bypassed the lingering D0 around Cayey.

Looking Ahead

A wet weather pattern is in store for much of the southern and eastern U.S. The combination of moisture associated with the remnants of Hurricane Willa, a pronounced southward dip in the jet stream (a trof), and a blocking high over the northern Atlantic Ocean will lead to a wet and colder weather pattern across the East. The storm responsible will continue to track across the nation’s southern tier, having already produced moderate to heavy rain and localized flooding in parts of the Four Corners Region. The storm will bring moderate heavy rain across the Gulf Coast States before churning slowly up the East Coast over the weekend, producing wind-swept rain and inland snow. A second faster-moving system will follow the Nor’easter, maintaining the threat of rain and high-elevation snow in the Northeast. Meanwhile, much-needed moisture will sweep across Northwestern drought areas in two waves, with the second system early next week potentially leading to fresh snowfall in the central and northern Rockies. Despite the nation’s active weather, the Southwest will turn drier. The NWS 6- to 10-day outlook for October 30 – November 3 calls for near- to above-normal precipitation over much of the nation, with drier-than-normal weather limited to the West Coast and lower Southeast. Cooler-than-normal weather is expected across the eastern third of the nation and from the central Plains to the Great Basin, while above-normal temperatures linger across the western Gulf Coast and in the Pacific Coast States.

Wildfires are happening.  But the risk is rapidly declining. More Information here.

The below are the forecasts by month for wildfires. Notice the area of risk is shrinking.  

Additional information can be found here.

And we do not want to ignore floods.

Reservoirs and Stream Flow

Let us look at California

2.  Last Week’s Weather

Here is what happened with precipitation during the most recent week.  The maps are in sync with the crop reports in terms of the period of time covered.

It is useful to look at temperature in a few different ways.

First let’s look at the Minimum Temperature.

And here is the snow situation which is less than the prior week.

For comparison purposes here is the prior week

And now the weekly maximum temperature

And for many purposes the average deviation from Normal or Climatology is very useful.

And here is a graphic that pulls a lot of information together. Image provided by the NOAA/ESRL Physical Sciences Division, Boulder, Colorado see website. It shows the demands of the atmosphere for moisture from the ground and is based on temperature, wind, relative humidity and solar radiation. It tells you nothing about how much precipitation you will get but how much you need to retain the same level of soil moisture.

Soil Moisture is a very important part of understanding drought. I uploaded the graphics in pairs this week (which is easier for me and we will see if they are still able to be read. You can click on them and the pair will enlarge.

Soil Moisture is a very important part of understanding drought.

Surface	Subsurface
The numbers in parentheses show the changes by state. Re the situation with surplus water,  the number of states with Topsoil (near surface) surpluses has decreased by 6 from last week and the number of states with Subsoil (subsurface) surpluses has decreased by 3. It is not always easy to know how to relate to a moisture surplus. Is it a positive moisture reserve or is it too wet to work the ground?
Re those states with deficiencies, The number of states with Topsoil (near-surface) deficiencies has not changed from last week and the number of states with Subsoil (deeper) deficiencies has decreased by 1.

3. Current Forecast for Precipitation and Drought.

First we show the Month of October Forecast Issued on September 30 and then the Seasonal Forecast through December which was issued on October 18 with the full Seasonal Outlook. These two forecasts are issued by the same agency but to obtain them you need to access two different links here and here. We either show the latest or both in this report. Sometimes we show them in more than one place in this report for the convenience of the reader.

And here is the longer seasonal drought forecast which was issued on October 18, 2018.  We will discuss this forecast in our Saturday 3 – 4 Season forecasts by NOAA and JAMSTEC,

And now the current precipitation forecasts so that we can make our own assessment of the drought forecast. Here I provide the weather forecasts for different periods of time in October which should allow the reader to assess the likelihood of this forecast working out as shown over the next three to four weeks. (Since we publish this week on Thursday, we will update the discussion for the Week 3 – 4 forecast when it is updated on Friday October 19. This is important as the current Day 6 – 14 forecasts and the week-old week 3 – 4 forecast overlap to some extent.

Now let’s look at the forecasts. Because temperature is so important right now re this drought I have switched over to the same format we use on Mondays. When we publish Thursday night, the Week 3 – 4 forecast is a week old but it then updates on Friday and we then update the discussion accordingly. It has not been updated.

First Temperature

This shows magnitude rather than probability of  being higher or lower than Normal and shows the middle day of the five day period.	The cool anomaly seems to be slowly moving east and deamplifying.		↑ ←  The Week 3 – 4 forecast was updated on Friday October 26. It is a typical El Nino Pattern.

The five day QPF is shown above. The units are different than the other maps i.e. in units of precipitation (inches) not probabilities of exceeding or being less than climatology.	The pattern is slowly moving east. Notice the wet Southeast. There is a risk of flooding for certain river valleys in the areas shown having high probabilities for precipitation		↑ ←  The current Week 3 – 4 forecast was updated on Friday October 26. It is a typical El Nino Pattern. Notice the warm/dry Northwest and cool/wet Southwest. Also notice that the Southeast continues to look wet. Termites will be happy. .

Here is another useful graphic from my weekly report which also updates automatically.

The below is of interest.

4. U.S. Crop  Information

The below is repeated from prior weeks and we will continue to show it until USDA updates the information.

And now released this week.

Below are more details and there is more information this week as the planting season advances.

This summarizes the situation which is very much different than the report last week  for a  number of reasons including we removed the crops that are essentially fully harvested. In some cases there is slight improvement and this is best seen in the detailed tables below. It is getting to be difficult preparing this table separate from the information above and below. The reason for that is that in general there are at this point in time three parameters reported:

1. percent planted

2. percent that has developed to a key point

3. crop condition

Plus there are two reference points: last year and the five year average. So it is harder to assess the six measurements and arrive at a single conclusion for a crop but I have taken my best shot at it. For those with a more serious interest I suggest you review the tables below and the text summary above which is what I have done to populated this table which has not changed since last week.

* Cotton has had a good year but not as good as last year which was either a record or close to a record. 

5. International Crop and Weather Related Information

Sometimes a map is useful.

I am now routinely including the precipitation report for Mexico since storms do not respect borders.

Here is the six-month result of these dry weeks.

6. Prior Month and when available the Current Month-to date Weather (excluding prior week)

Current Week

For reference purposes here is the precipitation information for the prior seven days.

Then we show month to date data.

And then temperature:

You can generate a wide variety of different graphics here.

7. Science Theme When we Have One.

No Science Theme this week.

8. Additional Reference Information

Reservoir Status

We update these graphics when we receive new ones. They do not auto-update. They tend to change slowly.

This article provides a little background on the problem.

We have added more rivers to the discussion. Above we have reservoirs and they are of course connected by rivers. Both are important and provide insight.

Below is a more complete description of

Sequence of drought occurrence and impacts for commonly accepted drought types. All droughts originate from a deficiency of precipitation or meteorological drought but other types of drought and impacts cascade from this deficiency. (Source: NDMC)

Source:  National Drought Mitigation Center, University of Nebraska-Lincoln, U