August 2015 Drought Report

Overview

The weather and upper-level circulation during August 2015 were influenced by the North Pacific and North Atlantic subtropical high pressure centers (mostly in the south) and an active jet stream (mostly in the north and east of the Rockies). This combination of weather factors resulted in a generally warmer- and drier-than-normal month across much of the West, South, and New England, and cooler-than-normal conditions from the Central Plains to Mid-Atlantic States. Above-normal precipitation fell with showers and thunderstorms along frontal boundaries from the Northern Plains to parts of the Southeast, bringing localized relief from drought. But drought and abnormally dry conditions rapidly expanded in the Southern Plains to Lower Mississippi Valley; drought and abnormal dryness expanded or developed in the Ohio Valley, Mid-Atlantic, and Northeast regions; and drought intensified in the Pacific Northwest and into the High Plains of Montana. Wetter-than-normal conditions across Hawaii and much of Alaska contracted drought in those states. El Niño-enhanced dryness continued across much of the Caribbean. In spite of rainfall from a weakened Tropical Storm Erika, August was drier than normal across most of Puerto Rico. Erika's rainfall contracted abnormal dryness on the island, but moderate to extreme drought expanded. When integrated across the CONUS, August 2015 ranked as the 28^th driest August in the 1895-2015 record. On balance, the national drought footprint expanded when compared to last month, increasing from 26.0 percent of the U.S. as a whole to about 28.4 percent of the U.S. in moderate to exceptional drought, according to USDM statistics. According to the Palmer Drought Index, which goes back to the beginning of the 20^th century, about 21.8 percent of the CONUS was in moderate to extreme drought at the end of August, an increase of about 2.7 percent compared to last month.

Percent area of the CONUS in moderate to exceptional drought, January 4, 2000 to present, based on the U.S. Drought Monitor.

Palmer Drought Index

The Palmer drought indices measure the balance between moisture demand (evapotranspiration driven by temperature) and moisture supply (precipitation). The Palmer Z Index depicts moisture conditions for the current month, while the Palmer Hydrological Drought Index (PHDI) and Palmer Drought Severity Index (PDSI) depict the current month's cumulative moisture conditions integrated over the last several months. While both the PDSI and PHDI indices show long-term moisture conditions, the PDSI depicts meteorological drought while the PHDI depicts hydrological drought. The PDSI map shows less severe and extensive drought in parts of the West than the PHDI map because the meteorological conditions that produce drought and wet spell conditions are not as long-lasting as the hydrological impacts.

Used together, the Palmer Z Index and PHDI maps show that short-term dry conditions occurred over much of the Pacific Northwest and Southern California, resulting in intensifying long-term drought in August compared to July. Short-term dry conditions in the Lower Mississippi Valley and most of Texas continued to reduce the long-term wet conditions, especially in the southern half of Texas. Short-term dry conditions in parts of the Southeast, Mid-Atlantic, and Northeast States intensified the long-term dry conditions in the Carolinas and expanded drought in the Northeast. Short-term wet conditions in parts of the Northern Plains expanded long-term wet conditions, compared to last month.

Standardized Precipitation Index

The Standardized Precipitation Index (SPI) measures moisture supply. The SPI maps here show the spatial extent of anomalously wet and dry areas at time scales ranging from 1 month to 24 months.

The SPI maps illustrate how moisture conditions have varied considerably through time and space over the last two years. Dryness in the Pacific Northwest is evident at all time scales, but is most severe at the 3- to 9-month time scales. Wet conditions are evident in California on the 1- to 3-month SPI maps, but June-August is the heart of the dry season, so above-normal precipitation at this time of year does not contribute much to California's hydrology. Dry conditions are evident for the state from the 6- to 24-month time scales. Wet conditions are evident for parts of the Southwest and Midwest to Ohio Valley at most time scales, except the 1-month time scale where near-normal to dry conditions dominate. Parts of the Southern Plains to Lower Mississippi Valley are dry at the 1- to 3-month time scales. But the extreme wetness at the end of winter and most of spring, especially in Texas and Oklahoma, give the Southern Plains a wet depiction on the 6- to 24-month SPI maps. Parts of the western Great Lakes have been dry at the 2- to 9-month time scales. Dryness is evident in parts of the Northeast to Mid-Atlantic States at the 1- to 2-month time scales, and in parts of the Northeast at the 6- to 24-month time scales. Parts of the Southeast, especially in and around the Carolinas, are dry at all time scales, especially at the 3- to 24-month time scales.

Standardized Precipitation Evapotranspiration Index

The SPI measures water supply (precipitation), while the SPEI (Standardized Precipitation Evapotranspiration Index) measures the combination of water supply (precipitation) and water demand (evapotranspiration as computed from temperature). Warmer temperatures tend to increase evapotranspiration, which generally makes droughts more intense.

1-month SPEI for current month.

1-month SPI for current month.

During August 2015, temperatures were below normal from the Central Plains to Ohio Valley, and much above normal in the West, along the Gulf of Mexico coast, and in New England. The warmer-than-normal temperatures amplified the dry conditions in the West when the 1-month SPEI is compared to the SPI. The combination of heat and dryness of the last several months has been so severe that Washington has had the most extreme SPEI in the 1895-2015 record at several time scales this year (3, 4, 5, 6, 7, 8, 9 months). The combination of heat and dryness gave Oregon the second most severe June-August SPEI on record.

3-month SPEI for current month.

5-month SPEI for Washington State, April-August, 1895-2015.

The persistent above-normal temperatures in the West have resulted in more severe SPEI values, compared to the SPI, for much of the last six years (SPEI maps for the last 3, 6, 12, 24, 36, 48, 60, 72 months) (SPI maps for the last 3, 6, 12, 24, 36, 48, 60, 72 months). The excessive heat has exacerbated drought conditions.

This is especially the case in California, where temperatures have been record warm for the last 12 months and well above average for each of the last four years. The state has had the most severe 24-, 36-, 48-, 60-, and 72-month SPEI in the 1895-2015 record. Even without the heat, the last 48 months have been the driest on record for California, according to the 48-month SPI. The SPI for the other time scales (24 to 72 months) was not a record.

California statewide 12-month temperature, September-August, 1895-2015.

California statewide 48-month SPEI for August, 1895-2015.

Regional Discussion

USDA topsoil moisture short to very short

USGS monthly streamflow percentiles

CONUS Agricultural & Hydrological Impacts:
Drought conditions were reflected in numerous agricultural, hydrological, and other meteorological indicators, both observed and modeled. According to August 31^st U.S. Department of Agriculture (USDA) reports, only ten percent of the nation's corn crop, eleven percent of the soybean crop, and 18 percent of the pastures and rangeland were rated in poor to very poor condition. As of September 1^st, 20 percent of the nation's hay, 20 percent of the cattle inventory, and 19 percent of the winter wheat production were in drought. But 36 percent of the nation's topsoil and 34 percent of the subsoil were short to very short of moisture (dry to very dry). Most of these statistics were increases compared to the end of July. And conditions varied considerably from state to state.

Drought conditions at the end of the month, as depicted on the September 1^st USDM map, included the following CONUS core drought and abnormally dry areas:

• Moderate (D1) to severe (D2) drought covered a large part of the western U.S., with extreme (D3) to exceptional (D4) drought extending from California and Nevada into the Pacific Northwest. —
  • The lack of a mountain snowpack to provide spring and summer meltwater has resulted in record to near-record low streamflow in the Cascades and coastal streams of Oregon and Washington, in the northern Rockies, and in northern and central California. Groundwater across the West is depleted. Rain fell in parts of the West, mainly coastal Washington and Oregon, improving streamflow on a scattered local basis. But most of California, Nevada, and the Pacific Northwest had few rainy days with long runs of consecutive dry days. The rainfall improved soil moisture conditions in some areas, but soil moisture was severely depleted along the West Coast and into the Northern Rockies. The USDA estimated that 86 percent of the topsoil in Oregon, 80 percent in California, 73 percent in Washington, and over 50 percent in Idaho, Montana, Nevada, and Utah was short or very short of moisture. Subsoil moisture conditions were just as dire with over 80 percent short or very short in California, Oregon, and Washington; 60 percent or more in Nevada and Utah; and over 50 percent in Idaho and Montana. Persistent hot temperatures, especially in the Northwest, increased evaporation (Evaporative Stress Index and Evaporative Demand Drought Index) which stressed vegetation. August 31^st USDA reports indicated that 68 percent of the pastures and rangeland in Washington, 64 percent in Oregon, and 60 percent in California were rated in poor to very poor condition, which are large increases compared to four weeks ago. The prolonged duration of the dryness over the last six months to four years has severely depleted reservoirs in most western states, especially in Nevada, New Mexico, Oregon, Washington, and California. The drought contributed to the development of numerous large wildfires in the West, especially in the Northwest during the last half of the month.
• Moderate to severe drought continued in the Southeast, with extreme drought in southern Florida. —
  • Areas of above-normal rainfall contracted drought locally, but drought expanded in other parts of the Southeast. By the end of the month, drought impacts were manifested by low streamflows, reduced groundwater, low soil moisture conditions, and stressed vegetation, especially in the Carolinas. August 30^th USDA reports indicated that 55 percent of the topsoil and 58 percent of the subsoil in South Carolina, and 58 percent of the topsoil and 53 percent of the subsoil in North Carolina, were short or very short of moisture. These values are improvements compared to the previous month in South Carolina, but a worsening of conditions in North Carolina. By August 31^st, 44 percent of the pastures and rangeland in North Carolina, and 21 percent in South Carolina, were rated in poor to very poor condition.
• Abnormally dry conditions with moderate to extreme drought continued to expand in the Southern Plains and Lower Mississippi Valley. —
  • These "flash drought" conditions expanded due largely to continued dry conditions this month. Parts of Texas and Louisiana had little to no rain, with long runs of consecutive dry days. Soils continued to dry out, with the USDA estimating about two-thirds of the topsoil in Texas and more than half in Louisiana and Mississippi short or very short of moisture, and more than half of the subsoil in those three states short or very short, by August 30^th. Nearly 30 percent of the pastures and rangeland in Texas and Louisiana were rated in poor to very poor condition by the end of the month. Several large wildfires developed in Texas after the middle of the month. In western Texas, even though late winter and spring were excessively wet, some of the reservoirs were still well below average.
• Pockets of abnormally dry to moderate drought conditions expanded in the Northeast. —
  • Unusually dry weather during August added to long-term dry conditions, especially along coastal New England. This resulted in low stream levels, decreasing groundwater levels, and drying soils. The USDA estimated that over 50 percent of the topsoil was short or very short of moisture in Delaware, New Jersey, and Pennsylvania. Well above-normal temperatures, especially in New England, increased evaporation which added stress to vegetation.
• Pockets of abnormally dry to moderate drought conditions remained or expanded in parts of the Midwest. —
  • Groundwater and soil moisture deficits were evident in places, with the USDA estimating about a third of the topsoil short or very short of moisture in Indiana and Ohio.

Hawaii: August 2015 was wetter than normal at most of the stations in Hawaii. The August precipitation resulted in a wet pattern for the last 2, 3, 5, and 6 months for most stations. Dryness was evident at the 8, 11, and 12 month time scales, especially for stations in Oahu and most of The Big Island, and at the 24 and 36 month time scales for most of the stations across the islands. On the USDM map, moderate to severe drought decreased slightly to about 24.1 percent of the state.

Alaska: Alaska was generally drier than normal at the southwestern stations and warmer than normal at the south coastal and panhandle stations, with wetter- and colder-than-normal conditions elsewhere. This precipitation pattern was evident at the 2- and 3-month time scales, but a more mixed pattern was evident at the interior stations at longer time scales (last 5, 6, 8, 11, 12, 24, and 36 months). Similar precipitation percentile patterns were evident at the higher-elevation SNOTEL stations (last 1, 3, 6, and 12 months). On the Alaska climate division maps, dryness dominated in the southwest at the one-month time scale then across more of the west at longer time scales (last 2, 3, 8, 11, 12 months). The August temperature anomaly pattern held for the last 2 to 3 months, with some mixing of temperature anomalies at the interior and northern stations, but warmer-than-normal temperature anomalies dominated the state at longer time scales, both on the station maps (last 8, 11, and 12 months) and climate division maps (last 1, 2, 3, 8, 11, 12 months). Along with the below-normal precipitation, August streamflow was significantly reduced in the southern and southwest areas, while August precipitation maintained the streamflow in other areas. The below-normal precipitation and above-normal temperatures helped to keep soils dry along the south central coast. Moderate drought contracted to cover about a sixth (17.8 percent) of the state, with abnormal dryness and drought covering nearly three-fourths (70.9 percent), on the September 1^st USDM map.

Puerto Rico: El Niño created atmospheric conditions which inhibited tropical cyclone activity, as evidenced by the collapse of Hurricane Danny and weakening of Tropical Storm Erika as they approached or crossed the Caribbean. Consequently, El Niño-enhanced dryness continued across the Caribbean during August 2015. In spite of receiving rain from Erika, the eastern and southern portions of Puerto Rico were still drier than normal during August. A pattern of drier-than-normal conditions in the south and east, and wetter-than-normal conditions in the northwest, has dominated much of the last year (last 2, 3, 6, 8, 11 months). The dryness was reflected in low to record low streamflow in the streams on the eastern half and southern portions of the island, as well as decreasing groundwater and reservoir levels and water rationing. On the September 1^st USDM map, abnormal dryness and drought shrank to about 78.8 percent of Puerto Rico, but moderate to extreme drought expanded to 63.8 percent of the island. This included 24.9 percent in the extreme drought category. This month marks the greatest extent of drought in Puerto Rico in the 2000-2015 USDM historical record.

CONUS State Precipitation Ranks:

The August precipitation anomaly pattern of dryness in the Northwest, California, Southern Plains to Lower Mississippi Valley, Mid-Atlantic, and Northeast was reflected in the state ranks, with 21 states ranking in the driest third of the historical record. Spotty above-normal precipitation fell over parts of many states, especially in the West, which tempered their ranks. Louisiana was the only state to fall in the top ten driest category, with the tenth driest August in the 1895-2015 record, but Connecticut was not far behind with the eleventh driest August.

The summer was drier than normal across parts of the Southern Plains to Southeast, but the dryness was most pronounced in the Pacific Northwest, where Washington had the ninth driest June-August. Six other states ranked in the driest third of the historical record for summer.

The dryness in the Northwest extended back to the beginning of the year, with the northwestern states ranking at least in the driest third of the historical record for March-August and January-August 2015. Washington had the eleventh driest March-August while Oregon ranked ninth driest for January-August. California was also quite dry for the year to date, ranking fifth driest for January-August. Eleven of the last 15 January-August periods in California have been drier to much drier than normal. Altogether, ten states ranked in the driest third of the historical record for March-August and eleven for January-August.

In addition to states in the West, states in the Southeast and Northeast ranked in the driest third of the historical record for March-August and January-August. Connecticut was the only state east of the Rockies to rank in the top ten driest category for these time periods, with the tenth driest March-August and sixth driest January-August.

Eleven states ranked in the driest third of the historical record for the last twelve months, mostly in the West, Northern Plains, and Northeast. Connecticut had the driest rank, clocking in at twelfth driest for September 2014-August 2015.

Western U.S.

As noted above, dry weather has dominated the West for much of the last three to four years, resulting in significant hydrological (low lake, reservoir, and stream levels) and agricultural impacts. According to the USDM, 59.7 percent of the West was experiencing moderate to exceptional drought at the end of August, which is a little less than the previous month. The Palmer Drought Index percent area statistic for the West was 56.5 percent, an increase of about 7.7 percent compared to the previous month.

Except for an occasional interruption, the dryness has been accompanied by unusually and persistently hotter-than-normal weather. El Niño-enhanced tropical moisture and cloudiness from the eastern equatorial Pacific helped reduce temperatures over much of the West during July, but upper-level ridging enhanced by the North Pacific High blocked much of the tropical moisture in August and maintained warmer-than-normal temperatures across most of the West. Oregon and Washington had the warmest June-August and March-August on record. California and Nevada joined Oregon and Washington for the warmest January-August and September-August. As seen by the SPEI earlier, these record hot temperatures have increased evapotranspiration and exacerbated the drought.

Agricultural Belts

Primary Corn and Soybean Belt precipitation, August, 1895-2015.

Primary Corn and Soybean Belt precipitation, March-August, 1895-2015.

March serves as the beginning of the growing season for the Primary Corn and Soybean agricultural belt. The region had a generally mixed precipitation pattern this month, with August 2015 ranking as the 55^th wettest and 22^nd coolest August in the 1895-2015 record, regionwide. The growing season to date ranked as the third wettest and 45^th warmest March-August on record, regionwide.

NOAA Regional Climate Centers:

A more detailed drought discussion, provided by the NOAA Regional Climate Centers and others, can be found below.

Southeast — South — Midwest — Northeast — High Plains
West

As described by the High Plains Regional Climate Center, average temperatures were near normal for much of the region and precipitation varied across the region. Much of the region was on the drier side; however, areas receiving less than 50 percent of normal precipitation were not widespread and generally occurred in southern Wyoming, central Colorado, and pockets of Kansas and North Dakota. On the wet end of the spectrum, areas receiving greater than 150 percent of normal precipitation included a large swath running from southeastern Montana and northeastern Wyoming through South Dakota and into Minnesota and Iowa. The little drought that remained in the High Plains region improved over the past month. According to the USDM, the total area in drought (D1-D4) in the region decreased to under a half a percent. Every state in the region except for Wyoming is now drought free. At the end of the month, only a very small area of moderate drought conditions (D1) remained in southwestern Wyoming. Abnormally dry conditions (D0) were still present over western Wyoming, northwestern North Dakota, northwestern Kansas, and parts of western Colorado. However, cooler and wetter conditions eliminated D0 areas in Nebraska, South Dakota, and southern North Dakota. These cool, wet conditions at the beginning of the month allowed for the last area of D1 in Kansas to improve. Now that only D0 remains, this is the first time since early November 2010 that Kansas has been drought free. Montana's D3 coverage expanded eastward and increased by about 5 percent. Although portions of the headwaters of the Missouri River are in drought at this time, streamflows are near normal. Winds brought smoke from Pacific Northwest fires all the way to the High Plains and Midwest regions. The smoke had a wide range of impacts, including some benign and some harmful. For instance, smoke suppressed daytime temperatures this month, but also created beautiful sunsets. On the other hand, smoke also resulted in air quality issues, which caused respiratory problems for sensitive groups. Although smoke can reduce incoming solar radiation, which is important for crop development, there is no evidence that the smoke has negatively impacted crops.

As explained by the Southern Regional Climate Center, temperatures were generally near to below normal in the northern parts of the region and near to above normal in the south. August precipitation in the Southern region varied spatially from extremely dry across much of Texas and southern Oklahoma, to very wet in northeastern Arkansas, northern Mississippi, and western Tennessee. The driest areas of the region occurred in northern Louisiana and in central Texas, where stations averaged between 0 to 25 percent of normal rainfall for the month. Drier-than-expected weather over much of the region has resulted in the expansion of drought conditions throughout much of Louisiana, central Tennessee and eastern Texas. In Louisiana, most of the state is now experiencing moderate drought, with some severe drought conditions in the northern Parishes along the southern border of Arkansas. This severe drought extends through north eastern Texas and south eastern Oklahoma. In east central Texas, there is an small area of extreme drought.

As summarized by the Midwest Regional Climate Center, average temperatures for August ranged from near normal near the Great Lakes to 2 degrees F (1 C) below normal in the southwest parts of the region, and precipitation was below normal for most of the region. Drought was not a widespread concern in the Midwest despite the drier August conditions largely due to the plentiful rains in the preceding months. In fact, crop conditions were more affected by too much rain early in the summer (flooding and ponding of water in fields) with roughly 20 percent of the corn and soybean crops in Missouri, Illinois, Indiana, and Ohio rated as very poor or poor and only about half the crops rated as good or excellent.

As noted by the Southeast Regional Climate Center, temperatures were near average across much of the Southeast region during August and precipitation was highly variable across the region. The driest locations were found across portions of the Florida Panhandle, far southern Florida, northeastern North Carolina, and eastern Virginia, where monthly precipitation totals were between 10 and 50 percent of normal. Mean temperatures were above average in Puerto Rico and the U.S. Virgin Islands. Precipitation was below normal across much of Puerto Rico and the U.S. Virgin Islands, where Coloso, PR (1905-2015) observed its driest August on record with only 1.2 inches (30.5 mm) of precipitation.

Drought conditions improved in some areas but continued to worsen in other portions of the Southeast during August. The percentage of the region under drought-free conditions (less than D1) remained around 76 percent throughout the month. Moderate (D1) drought was completely ameliorated in northern Alabama and decreased in coverage across central Georgia. However, moderate drought conditions developed across portions of southern Alabama, the Florida Panhandle, and east-central North Carolina, with a small area of east-central Georgia experiencing severe drought (D2) by the end of the month. The localized area of extreme (D3) drought expanded slightly but shifted westward in far southern Florida, while extreme drought conditions persisted over eastern Puerto Rico despite some beneficial rainfall from Tropical Storm Erika. High winds associated with Erika caused an estimated $20 million in losses from Puerto Rico agriculture, particularly in the plantain and banana plantations. Farmers in the Big Bend area of Florida resorted to pumping water out of fields and pastures due to excessive rainfall during August, and white mold and mildew were also reported in some locations.

As explained by the Northeast Regional Climate Center, the Northeast wrapped up August with an average temperature of 68.9 F (20.5 C), which was 0.8 F (0.4 C) above normal. Of the eight states that saw above-normal temperatures, seven ranked this August among their top 20 warmest. August was a dry month for the Northeast with 2.99 inches (75.95 mm) of precipitation, which was 76 percent of normal. Eleven states were drier than normal, with four ranking this August among their top 20 driest. At the beginning of August, parts of New England and New York (totaling 10 percent of the region) were abnormally dry or experiencing moderate drought. Spotty rainfall led to the expansion of abnormal dryness in these areas mid-month. Abnormal dryness was introduced in parts of New Jersey, Pennsylvania, Maryland, and West Virginia mid-month, as well. By the end of August, 23 percent of the Northeast was abnormally dry or under moderate drought conditions, according to the USDM.

As summarized by the Western Regional Climate Center, near to above normal temperatures were observed throughout the West this month. August marked the fourth consecutive month of widespread above normal temperatures in the Pacific Northwest. Though the magnitude of departures was not extremely large, generally 1-4 F (0.5-2 C) above normal, several locations in the Southwest and Pacific Northwest reported one of their top-10 warmest Augusts. Areas of above-normal precipitation were scattered across the West resulting from different atmospheric features. Two low pressure systems, one in the middle and another at the end of the month, brought much-needed precipitation to western Washington and scattered areas of coastal Oregon northern California. Eastern Washington and Oregon and much of California remained drier than normal, though these areas typically receive little summertime precipitation. Scattered areas of above-normal precipitation were observed in the Intermountain West associated with thunderstorm activity. In the Southwest, areas of well above normal precipitation were observed in the elevated areas of northern Arizona, but precipitation was generally below normal in New Mexico. Large fires burned throughout the Northwest this month, concentrated in Idaho, western Montana, Oregon, Washington, and northern California.

The Southeast, Interior, and Northern regions Alaska observed above normal precipitation this month while the South central and Southwest regions were drier than normal. Anchorage observed only 0.97 in (25 mm) of rain, 30% of normal for August. Further south, above normal rainfall was observed throughout Hawaii in association with Hurricanes Hilda, Kilo, and Ignacio passing near the state. Honolulu recorded 7.63 in (194 mm) of rain for August, more than twice the previous August record set in 2004. Warm, moist, tropical air associated with these storms, anomalously warm ocean temperatures, and persistent high pressure over the state kept temperatures well above normal. Many locations experienced their warmest month on record of any month of the year, including Hilo, Big Island at 79.7 F (26.5 C) and Kahului, Maui at 82.9 F (28.2 C).

Pacific Islands: According to reports from National Weather Service offices, the Pacific ENSO Applications Climate Center (PEAC), and partners, conditions varied across the Pacific Islands.

In the U.S. Affiliated Pacific Islands (maps — Micronesia, Marshall Islands, basinwide), August 2015 was drier than normal at Koror and Lukonor, and wetter than normal at the rest of the primary stations.

Rainfall amounts were below the minimum thresholds (4 or 8 inches) required to meet most monthly water needs at stations in the Marshall Islands and American Samoa. These included Jaluit, Utirik, and Pago Pago. Utirik received 6.92 inches of rain in August, marking the tenth out of the last eleven months (since October) that have been drier than 8 inches. Jaluit recorded 6.33 inches, marking the seventh out of the last nine months that have been drier than 8 inches. Koror received 9.90 inches in August, which is more than the minimum threshold, but eight out of the last eleven months have been drier than 8 inches. The 4- and 8-inch thresholds are important because, if monthly precipitation falls below the threshold, then drought becomes a concern.

As measured by percent of normal precipitation, Koror and Lukonor have been drier than normal in both the short term (August and the last 3 months [June-August 2015]), the year to date [January-August 2015]), and the long term (12-month time scale, September 2014-August 2015). Kosrae was drier than normal in the long-term (last 12 months) but wetter than normal at the other time scales. The rest of the stations (Chuuk, Guam, Kapingamarangi, Kwajalein, Majuro, Pago Pago, Pohnpei, Saipan, and Yap) have been wetter than normal at all of the four time scales.

SPI values for seven time periods for Pacific Islands, computed by the Honolulu NWS office.

For additional, or more localized, drought information, please visit:

• The U.S. Drought Portal
• National, Regional, and State Drought Resources