May 27, 2021 Weather Impacts On Economic Activity - Post Drought Concerns

Written by Sig Silber

Updated at 4:15 pm EDT May 28, 2021 to reflect the Week 3 – 4 temperature and precipitation forecasts which seem to confirm a possible rotation to the north of the center of the drought area.

Of course everyone wants to see the Western Drought ease up and go away but some are thinking about post-drought impacts. The most significant impact would be the aftereffects of wildfires and we report on a talk given on this topic. But drought itself can create some level of similar impacts, namely debris flows. Crop production continues to look very good. See our latest video in our weekly education program on sustainable agriculture. It addresses farm economics this week. We have not removed the first video so that readers can see the introduction to this very important topic. Tonight’s article contains all of our regular features and as usual, we include an intermediate-term weather forecast.

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Perhaps it is premature to be thinking about post-drought impacts while we are mired in drought. But if you do not think ahead, you can not take any actions to improve the situation. The most significant post-drought impact perhaps is related to burn scars after wildfires. We expect more than the usual number of wildfires this summer. But drought itself can create a milder form of debris flows and reduced aquifer recharge if land has reduced ability to absorb water. I am especially concerned as I am involved through participation in a soil and water conservation district with maintaining a number of flood control dams. I do not have the data to assess it but increased rains may result in increased movement of sediment which would reduce the storage capacity of our flood control dams. In at least one case, that would be very serious. There are a lot of flood control dams in the U.S.. Crop production looks very good but in most cases you do not have a successful year without a successful harvest. With the current weather patterns that could be an issue. I guess I am wearing my worry cap tonight. It is my planning background showing itself.

Someplaces are warm

It seems that this did not trigger a power failure.

Earthquake endangers dirt dam.

Post Drought Impacts.

This is a very good webinar addressing California, Nevada and the Southwest Drought Outlook. You can access the full webinar including audio here. I spent a lot of time snipping graphics from the first two presentations but I realized that the third presentation was very important since the drought news is somewhat repetitive and the wildfire information is available in our LIVE article which is updated twice a day and is available here. Then click on the version of LIVE at the top of the stack and in that article you will find the wildfire forecasts. I am going to show one slide from the presentation that was made this Monday and then move on to the third presentation which is very important as it deals with post-drought hazards. Again I have snipped and show the exhibits but listening to the talk is the best way to learn what Luke McGuire presented. It is very important as when this drought breaks we may be at risk for events similar to what happens after wildfires.

But first one slide from the Wildfire Presentation.

This shows the normal progression of wildfires from May through August. The graphics shown in our LIVE Article and in this presentation are deviations from the above. The above shows what is normal by month and the graphics shown in most presentations show the deviation from what is considered normal. So if there is not red or green shown that does not mean that there no wildfires are forecast but that the number and size of the wildfires forecast is consistent with what would be expected. So in most cases (not in the above) what is shown as the expected change from what is considered normal.

I snipped the graphics for this presentation but I am not including them in the article to keep the article down to a manageable size. But I will provide one important piece of information which is that wildfires require fuel. In some areas up to 50% of wildfires are grass fires and if the prior year was a drought year, there is no grass so the number and intensity of wildfires might be reduced in the subsequent drought year.

Let’s move on to the Post-Drought Hazards. It is the same presentation so the same link gets you to the recorded presentation. You can access the full webinar including audio here. I highly recommend that people watch the third presentation. They are all good actually but the third one is something you do see that often.

Those are good questions and indeed they are addressed in the presentation.

This is an example of a recent debris flow subsequent to a wild fire.

Showing the difference between a burn scar and unburned forest floor. They used the term “roughness” and that may be the case in many places. But every situation is a little different.

I did not include the short video but the idea is that a fire can modify soil so that it does not absorb moisture and thus there is rapid runoff. To a lesser extent, a drought can also have such an impact.

Here it is quantified. On the right are some curves from different locations. The Y Axis shows precipitation intensity and the X axis is duration. If you are below the curve you do not have a debris flow. Above the curve you have a debris flow. As you can see it varies by location.

Here there is difference shown for fires that had high burn severity and low burn severity. The author did not go into it but I believe that drought can have some of the same impacts but less severe.

Here they take a look at the situation one or two years later. The severity of the burn impacts the time to recovery.

Here one location is quantified. You can see that after one year it does not take much to cause a debris flow. After 2 years there is a big difference. The confidence interval is pretty large. On the left you have rainfall intensity and it shows the return period for the various levels of intensity. Where it says 10-year that means that the return period is 10 years. A better way to put it is that in 1000 years one would expect 100 storms of this intensity or greater. Obviously we do not have 1,000 years of good data so there is some estimation going on. I have personal experience with this. When I was in the mining business, we had a bad storm in Arizona that damaged a dam used to store water for the concentrator. This is water that drained into a pool behind this dam. It was reported as a 100 year storm. The request came in for a large amount of money to replace this dam with something more sturdy. I denied the request as our financial situation was not good and I was foolish enough to say come back in 99 years. A year or two later they had another such storm. I think this is the link that describes the second storm. The point is you can have ten bad storms in 100 years and none in the other 900 years and the ten worst storms are called 100 year storms. So when someone is using that term it is best to have them define the term and provide the data. Nothing about weather data is simple.

Here is a different situation. Here it is less a case of regrowth but improvment of the soil conditions. I do not recall that speaker explained the reason for the improvement in soil conditions. But remember that if you are making pottery you use an oven to harden the “green” ceramic. It may be that some minor rain events might improve the ability of soil to absorb water. I did not have time today to do a literature search on this topic.

Now we introduce slope into the equation and something that was a surprise to me namely that south facing hillslopes have slower growth of vegetation. That is counter-intuitive to me except during dry times.

This summarizes what was conveyed in the previous slides.

This provides a useful link to the research and the author.

Important News

We might as well show the situation for the California Reservoirs here.

A number of reservoirs are in less than good shape and the recharge projections are not good.

Let’s looks at some other information now.

We update the above map each time we publish but more frequent updates can be obtained here.

Here is what the SNOTEL data is telling us about Spring runoff.

Purple and blue are better than red or orange. The SWE information tells us what remains in the mountains as snow. It is adjusted for the time of the year. There is not much left to contribute to Spring runoff.

I wonder if the new Climate Norms impact this graphic? I think the answer is “no” because I do not think that NOAA has gotten to that level of detail yet. They may wait until the next Water Year to apply the new Climate Normals.

Updates are available here. This is another route to obtain updated maps. Red and orange are not good. That is the point. There is a lot of red shown.

And here is the water year.

You can definitely see the north/south divide. The previous two graphics show what snow remains. This shows the cumulative precipitation from October 1 until now. So if there has been early runoff it will still show here but not in the graphic above. You can still see the north/south divide. In some sense, this is a more accurate picture possibly. But we do not know what the impact of the early runoff was. Was it beneficial or simply wasted? It is a very complicated question. Certainly, some plants and animals benefited from the runoff but it could make the fire season worse.

This shows the results for the Water Year which begins on October 1. The chart above shows the snow available to provide water that enhances streamflow and aquifer recharge. The Water Year was not great but the real problem is having two not great years in a row. By my calculations the drought began after the La Nina of 1998. But not all years were dry years. But since 1997 which was a powerful El Nlino, the ratio of La Ninas (which tend to be dry) to El Ninos (which tend to be wet) has been about 2:1. Combined with warmer temperatures that increase conveyance loses and cause early runoff and longer growing seasons, it has generally been dry but just a couple of years ago we were essentially drought free. But on an overall basis the period since 1998 has been drier than usual. Population is higher. So the water needs are greater. Many factors have combined to create a serious situation right now. Updates can be obtained here.

And it is always useful to look at the last seven days.

You can see where the green is. It was a pretty good week.

Let’s look at the current drought situation.

There is not much change week to week but you can look back in the table and see how much things have changed in a year.

I do not like the new format but you can see perhaps more yellow than green suggesting more degradation than improvement but it is fairly even.

More information can be found here.

Here we look at four time periods: one week, one month, six months, and a full year.

The new format of showing county boundaries which I hate now applies to all time periods. They may have been able to reduce the brightness of the county boundaries so that the change in drought is easier to see than it was last week. So perhaps I will get to like the new graphics.

You kind of have to look at this 4-Plex in reverse. The lower right map shows the situation today as compared to a year ago. This set of graphics shows that this drought has materialized over the past year.

It is easy to get confused by this graphic. The map in the lower right does not show that the drought was worse a year ago but the change from a year ago to today. So the drought now is much worse than a year ago.

Drought Discussion (The Regional links are live and will take you to the drought map for that Region)

This Week’s Drought Summary
Much of the western CONUS experienced below-normal average temperatures this week, with many areas across the Great Basin and Northern Rockies observing greater than 6°F negative departures. Above-normal precipitation in the West was limited to the high elevations of the Cascades, the Central Great Basin, Montana, and northern New Mexico. However, improvements were only warranted in western Montana and northern parts of New Mexico, where the heaviest precipitation fell. Elsewhere in the West, degradations were warranted due to declining snowpack, stream flows, and soil moisture. The Southern Plains and Gulf Coast also experienced negative 7-day average temperature departures. However, negative departures along the eastern Gulf Coast were driven by easterly to northeasterly flow early in the week whereas below-normal temperatures along the western Gulf Coast and Southern Plains were driven by above-normal precipitation (1 to 2 inches across the Southern Plains and well in excess of 3 inches through the Ark-La-Tex and along the western Gulf Coast). Heavy rains in the Southern Plains resulted in continued improvements across Texas this week, while high pressure across the Southeast exacerbated 30 to 60-day dryness in Virginia, the Carolinas, and Florida, leading to degradation of abnormally dry (D0) and moderate drought (D1) conditions. From the Central and Northern Plains eastward to the Atlantic Coast, most areas experienced temperatures 6°F to 9°F above-normal. Heavy rains fell across western portions of the High Plains Region, warranting minor improvements across the western Dakotas, while the larger improvements were observed from western Nebraska and Kansas westward to the Front Range. From the eastern High Plains Region to the Great Lakes, improvement and degradations were observed based on where the heaviest precipitation fell. In the Mid-Atlantic and Northeast, below-normal precipitation over the past couple of weeks and above-normal average temperatures this week resulted in D0 expansion from the Great Lakes to New England and into the Mid-Atlantic, with some D1 expansion in Upstate New York. Stream flows and soil moisture continue to rapidly decline across the Northeast, Mid-Atlantic, and portions of the Southeast.
Northeast
This week, above-normal temperatures (6°F to 12°F positive departures) and below-normal precipitation (0.5 to 2 inch negative departures) were widespread across the Northeast. USGS 7-day average stream flows have fallen below the 10th percentile across much of western and Upstate New York, New England, and the Mid-Atlantic. CPC soil moisture has also continued to fall to below the 10th percentile across Upstate New York, northern Vermont and New Hampshire, and southern Maine, corroborated by NASA SPoRT 0-200 cm soil moisture percentiles. Therefore, portions of western and Upstate New York and New England were downgraded to abnormally dry (D0) conditions this week, with some D1 (moderate drought) expansion in Upstate New York. Farther southward from Connecticut southwestward into the Mid-Atlantic, 30 to 60-day precipitation deficits (3 to 5 inches over the last 60 days) continue to accumulate, resulting in D1-D4 equivalent 30 to 60 day SPIs, and 7-day average stream flows falling below the 10th percentile in many of these areas. Soil moisture has also begun to rapidly decline, due to the above-normal temperatures this week. As such D0 was expanded across western Connecticut, portions of the Mid-Atlantic coast and Delmarva Peninsula, southeastern Pennsylvania, and central and western Maryland.
Southeast
Average temperature anomalies ranged from 4°F to 6°F above-normal in northern Virginia to 2°F to 4°F below-normal southward from South Carolina to Florida. Despite cooler than normal conditions for many southern areas of the Southeast, there were a few very warm days along the eastern seaboard, with highs reaching into the low-to-mid 90s, further exacerbating the increasing dryness over the past 60 to 90 days, particularly across Virginia and the Carolinas. Additionally, little to no precipitation was observed across most of the Southeast this week. With D3-D4 equivalent 30-day SPIs, 60-day SPIs continuing to fall, USGS 7-day average stream flows falling below-normal (10th to 24th percentile) and much below-normal (below the 10th percentile), and with having received 25 to 50 percent of normal precipitation (per AHPS), D1 (moderate drought) was expanded to cover much of eastern North Carolina and southeastern Virginia. D0 (abnormal dryness) was also expanded farther westward from Virginia toward the Ohio and Tennessee Valleys, as short-term dryness has begun to diminish stream flows (falling below the 24th percentile) in those areas. In South Carolina, some minor expansion of D0 and D1 has continued as soil moisture continues to dry out, exacerbated by this week’s warm spell, and based on 7-day rainfall totals and 30 to 60-day rainfall deficits. D0 and D1 areas were also modified in a similar manner across the southern Florida Peninsula for similar reasoning. Furthermore, fire risk is elevated across southern Florida, with a burn ban now in place for Collier County, along the southern Florida Gulf Coast. The Tennessee Valley has also continued to dry out in the last 30 days causing browning of vegetation in areas of extreme northwestern Alabama, extending northward into Tennessee, warranting D0 introduction. Elsewhere in the Southeast, sufficient 30 to 90-day rainfall totals and weak average temperature anomalies (+ or – 4°F) warranted a status quo depiction this week.
South
Heavy rainfall and flooding was the main concern for many locations in the Southern Region this week. Across eastern and southern Texas, the Ark-La-Tex, and southwestern Louisiana, many areas received in excess of 3 inches of rainfall this week, in addition to the heavy rainfall observed in recent weeks. Southeastern Texas and southwestern Louisiana were again some of the hardest hit areas, with several areas receiving 8 to 10 inches of rainfall, and more in some locations. The eastern half of Texas, although having become drought free this week, has switched to become excessively wet, with flooding ongoing in several areas. Farther west in Texas, further reductions in D0 (abnormally dry) and drought (D1-D4) coverage were warranted in areas receiving more than 2 inches of rainfall, and some green-up has been indicated across parts of western Texas in recent weeks. From northern Mississippi to central Tennessee, 30-day rainfall deficits are beginning to increase. D0 was introduced in south-central Tennessee, extending across into northwestern Alabama, as 30-day SPIs have fallen into the D0 to D1 range, despite near normal stream flows. This area also shows up well (D0 to D1 equivalent depictions) in the NASA SPoRT 0-100 cm soil moisture.
Midwest
Most rain fell across the western half of the Midwest Region this week, with some areas receiving in excess of 2 inches of rainfall. Most of the larger rainfall totals occurred in drought-free areas, but some D0 (abnormally dry) and D1 (moderate drought) reductions were warranted in southeast Minnesota and western Wisconsin, where some locations received more than 2.5 inches of rain. Unfortunately, for several abnormally dry and drought-stricken areas, precipitation remained below-normal this week, adding to short-term deficits. Coupled with above-normal average temperatures this week (9°F to 12°F positive anomalies) across the Great Lakes and Upper Midwest, increases in D0 coverage were warranted across western and central Minnesota and parts of the Arrowhead. Moderate drought (D1) was expanded from southeastern Michigan into northwestern Ohio also, as stream flows have fallen below the 10th percentile and soil moisture has continued to dry out in recent weeks (CPC soil moisture falling below the 20th percentile and NASA SPoRT 0-100cm depicting D4 conditions). D0 to D1 equivalent short-term (30 to 60-day) SPIs and below-normal (10th to 24th percentile) USGS 7-day average stream flows warranted expansion of D0 across central Indiana and the introduction of D0 across eastern Kentucky and southern Ohio.
High Plains
In the High Plains Region, a swath of 1.5 to 3 inches (locally more) of rain fell from western North Dakota southward to eastern Colorado and northwestern Kansas. This resulted in reductions in D0 (abnormally dry) and D1 (moderate drought) coverage in western Nebraska and eastern Colorado, with additional 1-category improvements in the drought depiction across southeastern Colorado. In the Dakotas, where long-term moderate (D1) to exceptional (D4 – South Dakota) drought is entrenched, the heavy rainfall, although beneficial, was only enough for minor reductions in D1 (moderate drought) to D3 (extreme drought) coverage in the western areas. Reports indicate much of this week’s heavy rains was immediately absorbed by the severely dry soils, with no runoff into empty dugouts or ponds. However, in some locations, the rain fell so quickly that it did not allow time for infiltration into the topsoils, resulting in erosion of topsoils. Furthermore, high wind events have increased the potential for evaporative loss of this moisture from the topsoils. Currently, very little vegetative matter is available for grazing, despite some isolated areas of green-up from recent rainfall. In eastern North Dakota, some D3 reduction was warranted in areas receiving more than 1.5 inches of rainfall, diminishing long-term deficits. However, in South Dakota, where above-normal temperatures (9°F to 12°F positive anomalies) and below-normal precipitation (less than 50 percent of normal precipitation), expansion of D0 (abnormally dry), D1 (moderate drought), and D2 (severe drought) coverage were warranted as 30-day SPIs have fallen to D3 to D4 equivalence and 30-day deficits (1 to 3 inches) continue to accumulate.
West
Most basin snow water equivalent (SWE) percentiles across the Western Region are well below-normal for the period of record (near and below the 65th percentile), especially in the Four Corners region (below the 5th percentile in Arizona and New Mexico). Only parts of the Pacific Northwest and areas of central Montana experienced near and above-normal seasonal snowfall. However, above-normal temperatures over much of the West in recent weeks to months has resulted in rapid snowmelt and, due to dry topsoils, much of the melt water has not made it into the rivers, lakes, and reservoirs. In California, USGS 7-day average stream flows across the coastal ranges around and north of the Bay Area, and extending eastward into the Sacramento River Basin, are rapidly declining having dropped below the 2nd percentile at many locations in the coastal ranges, and below the 10th percentile eastward into the northern Central Valley. CPC soil moisture ranks below the 1st percentile (corroborated by NASA SPoRT 0-200 cm soil moisture percentiles), NASA GRACE indicates severely depleted groundwater, and vegetation indices (VegDRI and VHI) indicate severe vegetation stress. Reports of reduced pasture forage, livestock requiring supplemental feed and/or being sold off are increasing. Additionally, stock ponds are running dry and farmers have been forced to haul water in several locations. There are also reports of increased well drilling in the Sacramento River Valley and groundwater levels have fallen so low near the Sacramento and San Joaquin River deltas that there is an increased risk of salt water intrusion. Given the worsening conditions, D4 (exceptional drought) was expanded eastward into the Sacramento River Basin from the coastal ranges in and around the Bay Area. Farther east, D3 (extreme drought) was expanded into the Lake Tahoe area, as rapid snowmelt has nearly eliminated remaining snowpack, resulting in declining stream flows in that region, which have fallen to below the 10th percentile at several stations. In northeastern California, D2 (severe drought) was expanded into the lower Klamath Watershed, as USGS 7-day average stream flows have fallen below the 10th percentile and groundwater remains severely depleted (D3 to D4 equivalent, per NASA GRACE). Furthermore, the Yurok Tribe Fisheries Department reported diseased juvenile fish during an annual assessment and project a catastrophic fish kill along the Klamath River.
Elsewhere across the Western Region, targeted degradations to D2 (severe) and D3 (extreme) drought in eastern Washington and D1 (moderate) and D2 drought in northeastern Oregon were made. CPC soil moisture indicates widespread soil moisture conditions below the 5th percentile and groundwater is depleted for many areas. These degradations also correspond well with VegDRI, which indicates increased stress on vegetation. Despite the poor soil moisture conditions, 7-day average stream flows remain near and below-normal across many areas east of the Cascades due to the near to above-normal seasonal snowpack leading into the summer months. Conversely, in Montana, above-normal precipitation (7-day accumulations in excess of 2 inches liquid water equivalent) fell across the western half of the state, with locally more than 5 inches falling near Flathead National Forest (per AHPS). The heavy rainfall resulted in targeted improvements in areas experiencing abnormally dry (D0), moderate drought (D1), and severe drought (D2) conditions. However, long-term deficits remain (10 inch liquid water equivalent deficits in some of the higher elevations of western Montana).
Caribbean
Heavy rains in excess of 2 inches fell across northern and eastern Puerto Rico, with locally higher (more than 8 inches) falling in eastern parts of the island. Heavier rains in the east eliminated deficits in and around northern Rio Grande, eastern Humacao, southeastern Naguabo, and southwestern Ceiba Counties. Despite many locations in north-central and northwestern Puerto Rico receiving 2 to 5 inches of rainfall, it was not enough to eliminate 6-month deficits (5 to 10 inches, per AHPS). Additionally, D0 was expanded southward from Hatillo and Arecibo Counties into the northern tip of Utuado County, as below-normal precipitation last week pushed 6-month deficits to 8 to 12 inches.
Severe drought continued to affect the US Virgin Islands this week. On May 14, 2021, a USDA Secretarial natural disaster declaration was issued for St. Thomas and St. John due to the recent drought.
This week St. Thomas had only 0.48 inch of rain at the Cyril E. King airport. It’s month-to-date (MTD) rainfall total was 2.31 inches or 94.7% of normal. However, its year-to-date (YTD) rainfall total of 7.69 inches was 69.4% of normal. The CoCoRaHS station at the Anna’s Retreat 2.5 ESE had a weekly value of 0.82 inch of rain and a MTD value of 0.94 inch. SPI values at the 1, 3, and 9 months indicate drought free conditions, while the SPI at the 9 months is indicative of moderate drought for St. Thomas.
St. Croix reported a weekly total of 1.01 inches at the Henry Rohlsen airport, which fell all on May 23. This was a new daily record, surpassing the previous record of 0.96 inch in 1984. The MTD rainfall total was 1.26 inches or 41.9% of normal. The YTD rainfall total was 5.90 inches or 58.2% of normal rainfall. The CoCoRaHS stations across St. Croix had a weekly total of 0.48 inch (Christiansted 1.8 ESE) and 0.91 inch (Christiansted 1.6 E) and a MTD total of 0.62 inch and 1.23 inches, respectively. SPI values for 3, 6, 9, and 12 months were indicative of moderate to severe drought.
Similarly, St. John had a weekly rainfall total of 0.93 – 1.26 inches, depending on the CoCoRaHS station. MTD rainfall total was 1.76-2.43 inches and YTD values were over 8 inches for the different CoCoRaHS stations. SPI values for all levels were indicative of abnormally dry to extreme drought.
Pacific
Abnormal dryness (D0) continues for northern and eastern Mainland Alaska. Temperatures were near to below-normal and precipitation near-normal state-wide this week, with the exception of the North Slope, which saw 4°F to 6°F positive 7-day average temperature anomalies. Near and above-normal snowpack across most basins and near to above-normal stream flows warrant no changes to the depiction this week.
Moderate drought (D1) was introduced to southwestern Kauai and southern Oahu in Hawaii. Easterly trade winds persisted for much of the week and 7-day average temperatures were a few degrees above-normal for both islands. Lower pastures on the west-facing slopes on Kauai and Oahu have reported deteriorating conditions (corroborated by NDVI). Furthermore, USGS 7-day average stream flows have fallen below-normal (10th to 24th percentile) to much below-normal (below the 10th percentile) on southern Oahu.
The weather features across the U.S.-Affiliated Pacific Islands (USAPI) during this USDM week (05/19/21-05/25/21) included a monsoon trough which extended from the west across Palau and most of the Federated States of Micronesia (FSM); an Inter-Tropical Convergence Zone (ITCZ) with associated trade-wind convergence extending from the east across the southern Marshall Islands (RMI) and well into the FSM; and an upper-level trough with upper-level lows over northern portions of the Micronesian region. Added to this mix were smaller surface troughs and weak circulations, mostly over western Micronesia. The upper-level trough generated divergence aloft across the length of Micronesia which enhanced showers triggered by the surface convergence. South of the equator, a dry ridge of high pressure dominated the weather over American Samoa, with mainly diurnal island convection producing limited showers.
Satellite-based estimates of 7-day precipitation (QPE) showed a band of rain extending across Micronesia associated with the monsoon trough and ITCZ, and another broken band extending southeastward, from Indonesia to south of the Samoan Islands, associated with the South Pacific Convergence Zone (SPCZ). Areas of 1+ inches of rain extended the length of Micronesia, from the equator to 10 degrees North latitude, with patches of 2+ inches over western Micronesia and a large area of 4+ inches associated with the ITCZ over eastern FSM and southern RMI. A band of 2-4 inches extended north of 10 N over parts of eastern FSM. The QPE depicted wisps of precipitation extending across the Marianas, although this QPE product does not detect the warm-topped showers of the Marianas very well. The QPE showed an area of 1+ inches of rain south and west of the Samoan Islands, associated with the SPCZ, with wisps of precipitation extending northeast across American Samoa.
With rainfall totals at 5.80 inches for the week and over 18 inches for the month, Palau continues to be drought free.
Across the Marianas, Guam, Saipan, and Rota each had less than an inch of rain this week. Guam was the only location to have a month-to-date (MTD) rainfall total above the monthly threshold of 4 inches to meet most water needs. However, local reports have stated that there are some areas that are dry and for this reason abnormally dry conditions persisted this week. Saipan and Rota’s MTD rainfall was less than 3 inches, securing another week of abnormally dry conditions.
This was a wet week for most of the Federated States of Micronesia. Chuuk, Pohnpei, and Kosrae each had over 8 inches of rain for the week. Lukunor, Kapingamarangi, Pingelap, Nukuoro, Ulithi, and Woleai had over 2 inches of rain. While Kapingamarangi has received beneficial rains the past few weeks, Kapingamarangi continues to recover from the long-term drought. For this reason, long-term abnormally dry conditions were unchanged this week. Ulithi’s drought classification was improved to D-Nothing since local reports stated that water catchment levels were in good shape. The other locations continued to be drought free.
Fananu and Yap had the least rain at 1.36 and 1.19 inches, respectively. However, they were left as D-Nothing this week.
Most stations across the Marshall Islands had a wet week, with rainfall totals surpassing the weekly threshold of 2 inches to meet most water needs. Mili had the most rain this week at 10.33 inches. Kwajalein had 3.62 inches of rain this week and a MTD total of 8.07 inches. Local reports stated that the vegetation in Kwajalein was mostly recovered, resulting in an improvement to its drought classification to abnormally dry. Majuro, Mili, and Jaluit had no drought concerns at the moment.
Ailinglaplap and Wotje had the least rain at 0.63 inch and 0.71 inch, respectively. Ailinglapalap’s drought classification of D-Nothing was left unchanged this week. Wotje was left as D2-SL since it was reported that some crops were dying and water rationing was in effect.
Although Pago Pago had only 0.39 inch of rain this week, D-Nothing continued as its MTD rainfall was over 7 inches of rain.
Looking Ahead
During the next 5 days (May 27 to 31), parts of the Pacific Northwest, much of the Great Plains and Corn Belt, and Mid-Atlantic are favored to remain wet. Some locations in the Central Plains could receive up to 2 to 4 inches of rainfall. Temperatures are forecast to remain below-normal for much of the period across the Central and Southern Plains, with temperatures starting out below-normal across the eastern CONUS before moderating to near-normal during the period. In the West, temperatures are expected to be much above-average, with forecast positive anomalies in excess of 20°F near the end of the 5-day period.
The CPC 6-10 day extended range outlook (valid June 1 to 5) favors enhanced odds for above-normal temperatures and below-normal precipitation across much of the West and Northern Tier to the Great Lakes, with above-normal temperature probabilities extending into the Northeast. Enhanced odds for below-normal temperatures and above-normal precipitation are favored across the Southern Plains and Lower Mississippi Valley, with odds tilting toward above-normal precipitation across the Southeast. In Alaska, above-normal temperatures are predicted across the Southwest Mainland and parts of the Alaska Peninsula, while enhanced odds for below-normal temperatures are predicted over the eastern half of the state. Above-normal precipitation is favored across much of Mainland Alaska, extending to the Panhandle.

Regional Reports

The Intermountain West is in Drought.

There is not a lot new here. But if you want to see the full report it is available here.

When I lived in Salt Lake we referred to the Great Basin as the Intermountain West. Here in New Mexico that term is not usually used since we do not relate to the Sierra Nevada Mountains…they are kind of far away. But from a climate perspective it makes sense.

Not an upbeat forecast.

Not everyplace is experiencing drought.

You can listen and watch the full presentation here.

They have integrated all the information

Streamflow looks good

Reservoirs are not perfect.

I assume that decreased salinity is good

Many would be happy with this sort of report.

This is an outlier. It is not a NOAA product but was used in a NOAA presentation. I guess they like their lawns and gardens well watered.

They get in a month what I get in a year.

You have seen this before which is why they included it in their recent presentation.

I can not tell the difference between the prior and current but those from that area probably can. I remember many years ago driving through Georgia on a wooden road and there was swamp on both sides. It is a wet area.

This is their main river and it is nice to see the flows average to above average.

I guess you have to know what the important wells are. Since I do not, I rely on the description that came with the slide.

This is complicated. But Zone 1 sounds fairly good. They are not storing any flood flows. But they are close to where they would prefer to be.

I do not know enough about the wildlife in the bay to know what the desirable level of salinity is. I grew up at the shore but much farther north than this area (New Jersey) so I am somewhat familiar with the dynamics of bays and the different wildlife that thrive in water that is transitioning from fresh water to sea water.

It is a little difficult to read the legend so I will go with the comment.

Contact Information

Soil Conditions

The result of the drought is very dry soil conditions

But one sees some wet areas for a change. There is not only the green but a lot of yellow. This is a model created analysis as we have limited measurements. But in reality we do not need a lot of measurements unless the goal is to enrich the companies that sell the measurement equipment. Precipitation is highly variable so expecting to be able to have enough measurement equipment is not very realistic. We now have satellite imagery.

Soil Dryness in More Depth.

It is not in color but it shows the weekly change by climate division. It is a little complicated. The shaded areas are where the index increased. The unshaded areas are where the index decreased. Negative numbers are dry and positive numbers are wet. But too wet is not good. So you have to interpret the shaded areas differently from the unshaded area. Below -4 is always bad. Above 1 is generally not good but the direction of change is important. When you try to put a lot of information on one graphic it can before difficult to interpret.

Surface Soil

One more in surplus and two fewer states short. It is difficult to interpret “surplus” as it could be more water than needed or it could be out and out flooding. “Short” is clear it being insufficient water. So this appears to be an improvement.

Subsurface

One fewer state short. This is not a big change but it is an improvement.

This basically tells you how much precipitation you need to stay even.

April Drought Outlook

You can see some shifting in the location of the drought but the overall intensity is not much changed.

The Seasonal Drought Outlook is actually a bit better than the prior forecast last month

The number of fires has increased quite a bit.

Since we are entering fire season it is time to start showing the wildland fire potential outlook. These will update automatically shortly after the month changes.

Red is bad, green is good.

I live in NM so this is a big concern here.

The Monsoon provides some relief in July.

Perhaps even more relief in August.

Flooding is improved this week.

We will probably be showing this graphic now each week. At this time of the year, we are looking for areas that are too cold for crops. Later we will be looking for areas that are too warm. It looks like the major danger from freezing is past.

Crop Progress Reports

Crop	Crop Progress	Crop Condition
Corn	Planted and Emerged looking very good	NA
Soybeans	Planted and Emerged looking amazingly good	NA
Cotton	Planted a little slow	NA
Winter Wheat	Headed just ok	Not Great
Spring Wheat	Planted and Emerged looking very good	NA
Sorghum	Planted a bit slow	NA
Rice	Planted and Emerged very good	Good
Oats	Planted, Emerged and Headed looking very good	Not Great
Barley	Planted and Emerged looking good	Not So Good
Peanuts	Planted a little slow	NA
Sugar Beets	Planted looking amazingly good	NA
Sunflowers	Planted looking good	NA
Pasture and Range		Extremely Bad

Additional Information can be found here.

Yellow is bad. This week there were just two states colored yellow: Texas and Oklahoma. But brown is worse than yellow and there were four states colored brown Kansas, Louisiana, Missouri and Iowa.

Agriculture Sustainability Videos

Introduction

Episode 7 Water Management

Episode 8 Farm Economics

News

Nothing to report tonight.

Intermediate-Term Weather Forecast

Showing from left to right, Days 1- 5, 6 – 10, 8 – 14, and Weeks 3 – 4 You can click on these maps to have them enlarge. Also, the discussions that go with these forecast maps can be found here (first two weeks) and here (Weeks 3 and 4).

First Temperature

And then Precipitation

It does not look like a winter progression but more like a summer pattern.

The Week 3-4 Discussion is always interesting so we include it in the article. Similar discussions for the 6 -10 Day and 8 – 14 Day Forecasts are available here.

Week 3-4 Forecast Discussion Valid Sat Jun 12 2021-Fri Jun 25 2021
The El Nino-Southern Oscillation is currently neutral while uncertainty exists regarding the fate of intraseasonal variability across the global tropics. An eastward-propagating envelope with MJO-like characteristics is currently in the vicinity of the antimeridian while atmospheric Kelvin waves are situated over the tropical Atlantic and Indian Oceans. Multiple equatorial Rossby waves are also analyzed across the Eastern Hemisphere, as evidenced by the two current invest areas denoted by the Joint Typhoon Warning Center. In addition, low frequency convection appears to be establishing a foothold near 150E, with forecasts across the tropics emphasizing this area in the future, rather than canonical tropical variability on the intraseasonal timescale. Regardless, tropical modes historically have limited influence on North American sensible weather during June (outside of potentially altering favored tropical cyclogenesis areas and associated resultant impacts). As a result, calibrated dynamical model guidance and long-term trends relative to the 1991-2020 period form the basis of the present outlook.
Model guidance is mixed regarding the forecast 500-hPa circulation across North America, resulting in particularly low confidence in the present outlook. The CFS and GEFS ensemble means both show similar patterns highlighted by elongated anomalous ridging extending from near the Aleutians southeastward through the Tennessee Valley and some degree of anomalous troughing across eastern Canada. The ECMWF ensemble mean is lower-amplitude, with anomalous ridging extending the length of the U.S.-Canada border. The JMA and Canadian ensemble means feature anomalous ridging south of the Aleutians and over the Northeast, with anomalous troughing over the Intermountain West. Individual models from non-operational centers in the SubX multimodel ensemble similarly show little consensus on the forecast circulation.
Below-normal temperatures are favored from the Central and Southern Plains through the Central Gulf Coast tied to the potential for enhanced precipitation concerns and high observed soil moisture levels. Above-normal temperatures are favored across much of the remainder of the CONUS, with higher probabilities centered across the Great Basin and Northeast. The former area is tied to the potential for anomalous ridging, with probabilities tapering to below 55% heading northward given uncertainty regarding the southward extent of any troughing. Increased probabilities for above-normal temperatures for the Northeast are favored for similar regions, although the western extent is limited by troughing considerations. Alaska also sees odds increased for above-normal temperatures given forecast ridging across much of the state and the robust long-term trends at the high-latitudes.
As noted above, enhanced precipitation chances exist across the Southern Plains and Gulf Coast tied to onshore flow and elevated antecedent soil moisture levels. Model guidance generally exhibits a dry tilt across the West, while long-term dryness trends are most substantial for the Pacific Northwest helping to increase below-normal probabilities here. Above-normal precipitation is slightly favored for the Northern Plains through Western Great Lakes with some suggestion of shortwave activity riding over top the ridge in the West, or potentially being downstream of some of the deeper troughing forecasts like the ECCC ensemble mean. Equal chances for precipitation exist across Alaska and the remainder of the CONUS given a lack of guidance consensus and generally weak forecast anomalies.
Sea surface temperature anomalies in the vicinity of Hawaii increase from west to east, resulting in increasing chances for above-normal temperatures moving from Hilo toward Lihue. A similar east-west gradient is shown in SubX guidance across Hawaii, with a slight dry (wet) tilt for Hilo (Lihue) while equal chances for rainfall exist in Kahului and Honolulu.

International

Overall it was a good week for agriculture around the World other than South America and the Middle East. Updates can be found here.

Energy Analysis

No Report This Week

Major Sources of Information Used in this Weekly Report. We will not be using them all each week but the reader is welcome to refer to these resources.

The U.S. Drought Monitor (the full report can be accessed here)
Selected graphics from our other Weather and Climate Reports are repeated in this report. These reports can be accessed by referencing the Directory here
Selections from the Tuesday USD Weather and Crop Bulletin (the full report can be accessed here) or here. Selections from the USDA Office of the Chief Economist can be found here. NASS Executive Briefings can be found here. A wide range of NASS Reports can be found here. USDA Foreign Agriculture Service Briefs can be found here and here and here. Other useful sources of information that I regularly utilize are the National Integrated Drought Information System (NIDIS) which can be accessed here and the USDA NRCS Weekly and Weather Climate Update which can be accessed here. A glossary of terms can be found here.

Science Feature

Double Dip La Nina Continued

I want to attempt to present a paper that explains why we have more La Ninas than El Ninos. I think you can read the full paper here. I am not positive of that because I am registered with ResearchGate but they did not ask me to log in so I think you can access the full article but hopefully I will present enough for readers to understand the concept. I am removing the article from what I am publishing tonight since I have not made any progress on this topic but it is of great importance so I will be coming back to it.

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May 27, 2021 Weather Impacts On Economic Activity – Post Drought Concerns

This Week’s Drought Summary

Looking Ahead

Surface Soil

Subsurface

Crop Progress Reports

Agriculture Sustainability Videos

Introduction

International

Major Sources of Information Used in this Weekly Report. We will not be using them all each week but the reader is welcome to refer to these resources.

Science Feature

Breakthrough Covid-19 Cases Remain Rare In The U.S.

To What Extent Are We Ruled By Unconscious Forces?

Related Posts

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