Written by Sig Silber

Updated at 6 pm EST to reflect the Week 3 – 4 Forecast and to remind everyone that the article also includes information on the NOAA Climate Change Assessment for 2019

Drought continues not to be a problem. We have the new three-month drought forecast and it looks good except for three states which we discuss. We report on a couple of recent webinars and review the state rankings of temperature and precipitation. We will publish recent reports on many crops as an Addendum to this article on Saturday night. An update tomorrow will complete our full set of regular weekly reports – then our intermediate-term weather forecast will cover both 28 days and the first 14 days of the forecast with automatic updates daily. This post already includes the Week 3 – 4 forecast update so we have the 28-day forecast herein.

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Directory

New Seasonal Drought Forecast

State Rankings

December Only

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Six Months July through December 2019 (second half of 2019)

NOAA reports on Climate Change and here is their most recent report. I have selected some graphics from their report and the database they used to prepare the report.

This is a good graphic

And this is very important

North Central U.S. Climate and Drought Summary and Outlook

Establishing Meaningful Drought Partnerships with Tribal Nations

This was one of a large number of webinars that take place.

And shifting to the Alaska and CONUS Intermediate-Term Weather Forecast

And then Precipitation

Actually, we did update the article and here is the NOAA discussion released with the Week 3 – 4 Update. It is not the best news for agriculture.

The Madden-Julian Oscillation is currently active and strong with convection progressing eastward recently from the Maritime Continent into the Western Pacific Ocean. Model forecasts predict continued MJO activity and eastward progression over the next couple weeks and greater uncertainty in the MJO state thereafter. This MJO is occurring with background ENSO-neutral conditions, although the atmospheric and oceanic conditions are on the warm side of ENSO-neutral. These climate conditions, as well as decadal timescale temperature trends, impact the current Week 3-4 temperature and precipitation outlooks.

While dynamical model forecasts show considerable uncertainty in the temperature and precipitation pattern for Week 2, the impact of MJO and the background climate state appear to influence the forecast pattern for the Week 3-4 period over North America, leading to considerable agreement among model forecasts. The Week 3-4 temperature and precipitation outlooks rely primarily on dynamical model forecasts from the NCEP CFS, ECMWF and JMA operational ensemble prediction systems, as well as the Subseasonal Prediction Experiment (SubX) multi-model ensemble (MME) consensus, a combination of 7 operational and experimental subseasonal ensemble prediction systems. A statistical forecast, using the current MJO and ENSO indices as predictors in a multivariate linear regression (MLR) to temperature and precipitation for the week 3-4 period, combined with decadal trends, was also consulted to assess the impact of the current climate state.

Dynamical models forecasts from the ECMWF, CFS and JMA ensembles, as well as SubX model forecasts, appear to be considerably influenced by the active MJO. Ensemble mean forecasts from the ECMWF, CFS and JMA operational models, and the SubX MME predict above average 500-hPa heights over the west coast of North America and Alaska and below average 500-hPa heights over eastern North America during the Week 3-4 period. The CFS and the SubX MME predict a deeper trough over the eastern CONUS in Week 3-4 compared to the ECMWF ensemble mean. The ECMWF ensemble also predicts a substantially stronger ridge over the Northeast CONUS than other model forecasts for the Week 2 period, and persists this circulation pattern into the beginning of Week 3.

The Week 3-4 temperature outlook reflects the consensus of the dynamical model forecasts and is consistent with the MLR statistical forecast based on MJO and ENSO, and decadal trends. Above normal temperatures are likely over Alaska and the western CONUS, from the Pacific Coast into western areas of the Great Plains states, extending from the Four Corners region to the Dakotas. Probabilities for above normal temperatures exceed 60 percent for the southern coast of Alaska and the Pacific Coast of the CONUS, consistent with the predicted impact of MJO related convective activity over the western Pacific. Probabilities of above normal temperatures also exceed 60 percent for Northwest Alaska, where decadal temperature trends are significantly positive. Below normal temperatures are likely for the eastern CONUS from the Southern and Central Plains and Great Lakes region to the Atlantic Coast. Equal chances of above and below normal temperatures are indicated for the southern Florida Peninsula, where models disagree on the forecast. Probabilities for below normal temperatures exceed 60 percent for eastern areas of the Southern Plains into the Central and Lower Mississippi Valley, where temperatures are likely to be below normal from Week 2 into the Week 3-4 period, and the ECMWF Week 3-4 forecast indicates the greatest chance of below normal.

The Week 3-4 precipitation outlook is based primarily on probability forecasts from the combined ECMWF, CFS and JMA ensemble prediction systems, as well as the SubX MME, and with some consideration of the influence of the currently active MJO. Model forecasts for the Week 3-4 period are consistent in predicting below median precipitation along the Pacific Coast of the CONUS, under a predicted ridge. Above median precipitation appears more likely to the east of the Northern and Central Rockies into the Northern Plains, where there is potential for the development of storm systems. While dynamical model precipitation forecasts are inconsistent on the outlook for Alaska, the ECMWF ensemble and the MLR of MJO impacts indicate above median precipitation is likely for the west coast of the state. Most model forecasts indicate below normal precipitation is most likely behind the predicted trough over the Eastern CONUS, from the Southern Plains northeastward across the Central Mississippi Valley into the Greats Lakes and Northeast regions. While the blend of operational ensemble model forecasts and the SubX MME consensus both predict likely below median precipitation for a large area of the Southern and Central Plains and the western Great Lakes region, equal chances of above and below median is indicated in the Week 3-4 outlook where there is greater disagreement among the model forecasts. Above median precipitation is likely from the eastern Gulf Coast region across the Southeast to the southern Atlantic Coast, as predicted by nearly all ensemble prediction systems.

Sea surface temperatures remain above average in the vicinity of Hawaii, and both operational and SubX models support above normal temperatures for the Week 3-4 period. Equal chances of above and below median precipitation is indicated for Hawaii due to poor model forecast agreement, with above median precipitation more likely to the north of the islands and below median precipitation more likely to the south.

Recent Precipitation Records

Here is the discussion that was released with the Week 3 – 4 forecast today. (we will add this when it is issued)

But looking at just the last seven days

Current Drought Conditions

Now we take a look at Thursday’s U.S. Drought Monitor Report.

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.

U.S. Affiliated Pacific Islands and the U.S. Virgin Islands.

Below is the map for just CONUS.

Last Week	This Week

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

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

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

No Change

No change other than a slight improvement in a small area.

No Change

Mostly improvement in Texas and to Louisiana and Arkansas with degradation in Oklahoma

No Change

Slight degradation in a small part of New Mexico and the mixed but mostly improvement in the states of Washington, Oregon and Idaho/

Here is the Discussion that was issued with the Drought Report. The Regional Headings can be clicked on to obtain maps and statistics.

This Week’s Drought Summary

Warmer than normal temperatures were common this week over the eastern half of the continental U.S., while temperatures were primarily near normal over the western half, with a few exceptions. Moderate to heavy precipitation was common this week along and east of the Interstate 35 corridor, excepting parts of the Northeast and the Florida Peninsula. In the West, moderate to heavy precipitation also fell in some of the higher elevation areas. For more details on the geographic distribution of precipitation and temperature anomalies, please see the regional paragraphs below. The only exceptional drought occurring in the United States, on Maui, was removed this week after a major precipitation event in Hawaii, where other improvements were also made. Heavy rainfall in northern and eastern Puerto Rico also ended the moderate drought there. In the central and eastern continental U.S., drought conditions generally improved in areas that received heavier precipitation, while some degradation occurred in locations in Texas and Oklahoma that remained drier. The depiction of moderate drought and abnormal dryness also changed in Idaho, Washington, and Oregon, where recent precipitation (or lack thereof) affected mountain snowpack and short-term precipitation deficits. For more details on changes made to the drought depiction, please see the regional paragraphs.

Southeast

Widespread precipitation fell in the Southeast region over the past week, with the exceptions of the eastern Florida Panhandle and the Florida Peninsula. Precipitation amounts ranged from about a half inch to as much as 2-3 inches across most areas that received precipitation. Temperatures were warmer than normal this week. The warmest areas were parts of Alabama, Georgia, South Carolina, and North Carolina, where temperatures soared to 9 to 12 degrees above normal in some locations. Due to the widespread rainfall, drought-free conditions continued in Alabama and South Carolina.

Midwest

Across the southern portion of the region (roughly the southeastern halves of Iowa and Wisconsin to the southeast), widespread precipitation of at least a half inch fell this week. The heaviest amounts fell from central and southern Missouri through southern portions of Illinois and Indiana, where precipitation amounts ranging from 2 to locally as high as 5 inches were common. Warmer than normal temperatures covered most of the region, particularly in Ohio and Kentucky and southern Indiana, where some locations were at least 15 degrees warmer than normal for the week. In contrast, northern Minnesota was 5 to 10 degrees below normal. Abnormal dryness ceased in western Indiana, where over 2 inches of rain fell. Elsewhere across the region, freedom from drought and abnormally dry conditions persisted.

Northeast

Precipitation over one-half inch fell in spots in the Northeast. The wettest areas (where precipitation ranging from 1-2 inches occurred) were found from Lake Ontario to northern Maine, generally near the Canadian border. Warmer than normal temperatures took place in the Northeast this week. Most areas, aside from central Pennsylvania and Maine, were 10 to 15 degrees warmer than normal for the week. Short-term dryness continued in Delaware this week, where streamflow and soil moisture were lower than normal. Aside from this area of abnormal dryness, the rest of the Northeast avoided abnormal dryness and drought for another week.

South

Most of the South had warmer than normal temperatures this week, though widespread rainfall led to reduction in drought conditions in parts of the region. Temperatures ranged from 10 to 15 degrees warmer than normal in Mississippi and Tennessee to generally 5 to 10 degrees above normal in Oklahoma and Texas. Excluding south Texas, moderate to heavy rain fell across the portion of the region to the east of the Interstate 35 corridor. The highest rain amounts, with some locations exceeding 3 inches, fell upon north-central Texas, southeast Oklahoma, Arkansas, far northeast Louisiana, and northern Mississippi. The heavy rain in east Texas and adjacent portions of Louisiana, Arkansas, and southeast Oklahoma led to improvement in drought and abnormally dry conditions in these areas, where short-term precipitation shortages were lessened, and streamflow improved. In areas west of the more widespread precipitation in Texas and Oklahoma, some of the drought and abnormally dry areas were expanded where short-term precipitation deficits grew.

High Plains

Across the High Plains region, primarily dry and near normal or cooler than normal conditions occurred, with the exceptions of south-central and eastern Kansas, where warmer than normal temperatures occurred and over a half inch of precipitation fell. Temperatures mostly ranged from 5 to 10 degrees cooler than normal in South Dakota and North Dakota this week. Moderate and severe drought continued in south-central and southwest Kansas, respectively, and no changes were made to the drought or dryness depiction in the region.

West

Temperatures varied across the West region over the past week. Eastern Utah and north-central Montana had temperatures 5 to 15 degrees cooler than normal, while western Utah was 5 to 10 degrees warmer than normal. Warmer temperatures continued in the eastern and southeastern plains of New Mexico, and abnormally dry conditions were expanded where high evaporative demand combined with lower recent precipitation amounts. Heavy mountain snow occurred in the Cascades, where abnormal dryness and moderate drought slightly improved as short-term precipitation deficits slightly lessened and snowpack grew. High elevation areas of Colorado, Wyoming, Idaho, Montana, northern Utah, and northern California received precipitation this week, while lower elevation locations generally stayed dry. Moderate drought and abnormally dry conditions shifted in Idaho in response to changing snowpack and precipitation deficits over the past week.

Alaska, Hawaii, and Puerto Rico

Heavy rain over the past week in northern and eastern Puerto Rico improved precipitation deficits and streamflow enough to end the moderate drought that had been going on, though abnormal short-term dryness remains in spots. Short-term precipitation in the Alaska Panhandle has been near or above normal, but long-term precipitation deficits remain in the area, so long-term drought and abnormal dryness continued another week. Very low snowpack was noted on the Kenai Peninsula, though sufficient precipitation was occurring to keep abnormal dryness at bay. In Hawaii, a major rainfall event drenched parts of the state, leading to widespread improvements in drought conditions this week. Exceptional drought on Maui ceased, severe drought was improved to moderate drought in northeastern Kaho’olawe, and the abnormal dryness on Oahu abated. On the Big Island, the abnormal dryness in the southern half of the island was removed, severe drought in northwestern reaches of the island improved to moderate drought, and moderate drought on the northern half of the island was mostly eliminated, save the aforementioned severe drought area and a remaining area of severe drought around Waimea.

Pacific Islands

During the Northern Hemisphere winter, the North Pacific subtropical high, and the low latitude Inter-Tropical Convergence Zone (ITCZ), migrate south toward the equator. The seasonal migration brings drier subtropical trade winds to the northern portions of Micronesia and ITCZ rainfall to the southern regions. The weather conditions across the U.S.-Affiliated Pacific Islands (USAPI) during this USDM week (1/8/20-1/14/20) reflected this seasonal pattern.

A weak circulation developed during the week near Koror, Republic of Palau, before drifting to the west and north. Most of the shower activity associated with this disturbance remained to the north of Palau. Parts of western Micronesia continue to be monitored for further development or intensification of short-term dryness. Closer to the equator, ITCZ-related showers soaked some islands, including Nukuoro. Across the Marianas, minor disturbances embedded in the northeast trades produced a few showers – but did not result in enough rain to ease dry conditions. On Guam, the Keetch-Byram Drought Index (KBDI) – indicative of fire danger – stood at 593 (on a scale of 0 to 800) at the end of the drought-monitoring period, down slightly from an earlier peak over 600. According to the National Weather Service, “vegetation [on Guam] is now starting to get stressed. The grass in the lawn here is turning yellow.”

In the Republic of Palau, short-term dryness continued to develop. During the first 14 days of January, the National Weather Service office (WSO Koror) received rainfall totaling just 0.97 inch. That observation site also ended 2019 on a dry note, with 0.39 inch reported from December 20-31. Based on that data, as well as reports of short-term rainfall deficits elsewhere in the Republic of Palau, abnormal dryness (D0-S) was introduced.

In the Marianas, drier-than-normal weather persisted on most islands. At the international airport on Guam, record-low December rainfall was followed by a total of 0.88 inch (36 percent of normal) during the first 14 days of January. Rota received 1.10 inches during the weekly drought-monitoring period – but reported less than two-thirds of an inch in each of the 5 preceding weeks. Saipan has received less than an inch of rain for 7 consecutive weeks. A few spots in the Marianas fared better in recent days – for example, Agat reported 1.95 inches of rain from January 10-12 – but abnormally dry conditions (D0-S) were retained for Guam and Rota and added to Saipan.

In the FSM, abnormal dryness (D0-S) was removed from Kapingamarangi, following a period of significant rainfall during the first half of January. Specifically, Kapingamarangi received 3.93 inches of rain from January 1-14, with one day missing. Much of the rain, 3.12 inches, fell from January 6-10. Meanwhile, a few spots in the FSM received heavy rain, with Nukuoro reporting 4.00 inches on January 13-14. Similarly, Ulithi endured a 6.98-inch deluge on January 10. In contrast, parts of Yap State have trended dry in recent weeks and will continue to be monitored for the need to introduce abnormal dryness. In addition, Lukunor received rainfall totaling only 0.03 inch during the drought-monitoring period – but this follows near-normal December rainfall, when 10.23 inches fell. Insufficient rainfall data is available to provide an analysis for Fananu.

In the Republic of the Marshall Islands, abnormal dryness (D0-S) was removed from Majuro, despite lingering low reservoir storage. Majuro received 4.03 inches of rain from January 8-11, boosting reservoir storage from 22.9 to 26.8 million gallons (from 64 to 74 percent of capacity). Though storage below 80 percent of capacity is indicative of drought concerns, the recent downpours on Majuro have eased those issues. Elsewhere in the RMI, there is neither dryness nor drought, except on Utirik. Recently updated data for Utirik indicates that rainfall has totaled less than an inch for 4 consecutive weeks, allowing abnormal dryness (D0-S) to develop. Weekly (January 8-14) rainfall totals were less than an inch on several islands, including Kwajalein (0.65 inch), but earlier wetness precludes the need to introduce dryness for those locations.

American Samoa remains wet, following a December rainfall total of 17.93 inches at the international airport. During the first 14 days of January, rainfall at the airport reached 4.41 inches.

Virgin Islands

The U.S. Virgin Islands (USVI) have entered the traditional winter dry season, but almost daily showers have been observed in recent weeks. The latest drought-monitoring period (January 8-14) was no exception, as frequent showers continued to provide relief in the wake of a drier-than-normal autumn wet season.

On St. Croix, January 1-14 rainfall at Rohlsen Airport totaled 1.94 inches (187 percent of normal). Standardized Precipitation Index (SPI) data indicated that short-term rainfall deficits have been eradicated, but longer-term impacts remain. For example, the USGS Adventure 28 well has begun to slightly respond, but the depth to water remains more than 4 feet lower than the beginning of 2019. Moderate drought (D1) persisted on St. Croix, but the designation was changed from “SL” to “L” to reflect long-term effects on groundwater.

Showery weather also continued across St. Thomas and St. John, where neither dryness nor drought was indicated. A CoCoRaHS observer near Anna’s Retreat on St. Thomas reported a month-to-date rainfall of 2.75 inches through daybreak on January 14. Meanwhile, a volunteer observer at Windswept Beach on St. John received a month-to-date total of 2.01 inches through sunset on January 13. USGS wells on both islands continued to respond to the winter rainfall.

Looking Ahead

Another winter storm system is forecast to traverse the Central Plains, Midwest, and eastern continental U.S. from Thursday, January 16 into the weekend of Saturday the 18th, delivering widespread rain, snow, and a mix of winter precipitation types. For January 16-21, the National Weather Service Weather Prediction Center is forecasting over three-quarters of an inch of precip