Drought - September 2012


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Issued 15 October 2012
Contents Of This Report:
Map showing Palmer Z Index

National Drought Overview

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Detailed Drought Discussion

Overview

September 2012 was another month with warmer-than-average temperatures (23rd warmest September on record, based on data back to 1895) and near-average precipitation (48th driest September), when weather conditions are averaged across the country. Like last month, cool fronts swept across the central and eastern U.S. (weeks 1, 2, 3, 4) while a strong high pressure system (High, or upper-level ridge) kept its stranglehold over much of the West, resulting in a monthly pattern of anomalous warmth in the West and below-normal temperatures in the Midwest and Southeast. Descending air ("subsidence") associated with the High inhibited precipitation in the Northwest to Upper Midwest, while passing fronts and the remnants of Hurricane Isaac triggered areas of rain from the Southern Plains to the Midwest and parts of the Northeast; monsoon showers brought rain to the Southwest (weeks 1, 2, 3, 4); and frequent storms gave Alaska the fifth wettest September in the state's 1918-2012 record. The dry weather in the Northwest and Northern Plains, in combination with the above-normal rainfall in the Ohio Valley and Southern Plains, helped the drought areas migrate westward and northward. Nationally, the moderate-to-exceptional (D1-D4) drought footprint increased slightly to about 54 percent of the country, compared to last month, while the percentage in the abnormally dry to exceptional drought category decreased to about 68 percent. About 17 percent of the country was in the worst drought categories (D3-D4, extreme to exceptional drought), a bit less than last month. The Palmer Drought Index, whose data base goes back 113 years, is relied upon for drought comparisons before 2000. The September 2012 Palmer value of 52 percent in moderate to extreme drought is a decrease of about 3 percent compared to last month, and the percent area in severe to extreme drought decreased to about 37 percent.

The U.S. Drought Monitor drought map valid October 2, 2012
The U.S. Drought Monitor drought map valid October 2, 2012.

By the end of the month, the core drought areas in the U.S. included:


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.

Palmer Z Index map Palmer Hydrological Drought Index map

Rain from frontal systems and the remnants of Hurricane Isaac (as seen on the Palmer Z Index map) effectively ended drought in parts of the Midwest (PDSI from end of September compared to end of August). Dry conditions in the Upper Midwest and Northern Plains, and warmer- and drier-than-normal weather across the Northern Rockies and Pacific Northwest, intensified drought in the Plains (both short-term [Z Index] and long-term [PHDI] conditions) and expanded drought to the north and west. Recent dryness (August and September Palmer Z Index maps) neutralized previously long-term wet conditions in the Northwest, while wet September conditions reduced longer-term dry conditions in the Northeast. The Palmer maps also reflect the long-term nature of the drought conditions. The Z Index and PHDI maps in combination show that precipitation brought relief to parts of the Southern Plains to Midwest and Northeast drought areas, and reduced precipitation continued to shrink long-term wet areas in the Northwest, but for the Upper Midwest to Central and Northern Rockies — drier-than-normal weather persisted over the existing drought areas.


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.

1-month Standardized Precipitation Index 2-month Standardized Precipitation Index 3-month Standardized Precipitation Index

The 1-month SPI shows the main area of dryness from the Pacific Northwest to the Northern and Central Plains and Upper Midwest, with other areas dry in parts of the Southeast and much of California. The western and central regions' dryness persists at 2 and 3 months, with dryness spreading across more of the Central Plains and into the Southern Plains and Southern Rockies at 3 months. At 6 months, the April-September growing season was quite dry across the Midwest and Great Plains agricultural belt and into the Rocky Mountain states as well as parts of the Southeast and coastal Mid-Atlantic. The 6-month pattern is generally evident at 9 and 12 months with expansion of dryness further into the West. Dryness at 24 months is concentrated in the Southern to Central Plains, Southern to Central Rockies, and Southeast. Wet conditions from the Southwest monsoon appear in places from 1 to 6 months, and wetness from frontal and tropical moisture stretches from the Southern Plains to Northeast at 1 to 3 months. The Pacific Northwest and central Gulf of Mexico coast are wet at 9 months, while widespread wetness dominates at 24 months from the Ohio Valley to Northeast.


6-month Standardized Precipitation Index 12-month Standardized Precipitation Index 24-month Standardized Precipitation Index


Agricultural and Hydrological Indices and Impacts

USDA topsoil moisture short to very short
USDA topsoil moisture short to very short
USGS monthly streamflow percentiles
USGS monthly streamflow percentiles

Drought conditions were reflected in numerous agricultural, hydrological, and other meteorological indicators, both observed and modeled.

Agricultural:

At some point during 2012, most of the counties in the country had been declared agricultural disaster areas by the U.S. Department of Agriculture (USDA). Based on end-of-September (September 30th) USDA reports, 55 percent of the nation's pasture and rangeland was rated in poor to very poor condition. Several states, from California to the Central Plains, had 80 percent or more of their pasture and rangeland rated poor to very poor, with virtually all of it so rated in Nebraska. Much of the nation's corn and soybean crops have been harvested, but winter wheat was 40 percent planted and its emergence was hampered by drought in several central and northwestern states, with 71 percent of the winter wheat in drought. While topsoil moisture has recovered in Midwest states receiving rainfall during the last couple months, more than 80 percent of the topsoil was rated short or very short of moisture from the Upper Midwest to Northern and Central Plains, and in the Rocky Mountain states.

Map showing USDA pasture and rangeland conditions
Map showing USDA pasture and rangeland conditions.

Hydrological:

USGS groundwater percentile map
USGS groundwater percentile map.

Meteorological:

Map showing number of days with precipitation
Map showing number of days with precipitation.


Regional Discussion

Hawaii: September 2012 was characterized by below-normal rainfall over the Big Island stations but a mixed pattern over most of the rest of the Hawaiian Islands. A similar pattern exists for the last 2 to 3 months. Longer-term conditions continued drier than normal (last 6, 12, 24, and 36 months, and year-to-date), especially for the southern islands. Moderate to extreme drought affected 51 percent of the state, a little less than last month.

Alaska: September 2012 was drier than normal in the southeast interior region and wetter than normal across most of the rest of the state. A similar pattern could be seen at 2, 3, and 6 months, but the pattern becomes mixed at longer time scales (last 9, 12, 24, and 36 months). An area of abnormal dryness covered the northern areas on the USDM map.

Puerto Rico: It was drier than normal across much of the island during September, but especially in the south and east. Streamflow averaged below normal for the month at several locations. A dry band stretched from the west coast to the central regions, culminating in a drier-than-normal eastern third of the island, at 2 to 3 months, and even at 6 months. But the drier-than-normal area transitioned to the southeast at longer time scales (6 months, year to date, and water year to date). The October 2nd USDM map had an area of abnormally dryness in the south central to eastern areas to reflect these rainfall deficits.

Current month state precipitation ranks 3-month state precipitation ranks

Nebraska statewide precipitation, May-September, 1895-2012
Nebraska statewide precipitation, May-September, 1895-2012.

A fourth of the U.S. was very dry (the driest ten percent of the historical record) during September 2012. The dryness was partially balanced out by a significant area (about 8 percent) that was very wet, resulting in a national rank for September 2012 of 48th driest September in the 118-year record. On a statewide basis, September 2012 ranked in the top ten driest Septembers for ten states — from the Northwest to the Upper Midwest — and ranked as the driest September for Montana, North Dakota, South Dakota, and Minnesota. Six other states ranked in the driest third of the historical record. The same spatial pattern of dryness existed at the three month time scale. Again, Montana and South Dakota, along with Nebraska, had the driest July-September on record. Eight other states had the tenth driest, or drier July-September and four other states ranked in the driest third of the historical record.

6-month state precipitation ranks 12-month state precipitation ranks

Wyoming statewide precipitation, January-September, 1895-2012
Wyoming statewide precipitation, January-September, 1895-2012.

The spatial pattern of dryness at the six month time scale is centered in the Central Rockies to Central Plains. The persistent dryness gave Nebraska and Wyoming the driest April-September on record, with six other states ranking in the top ten driest category. Twelve additional states were in the driest third of the historical record. A similar pattern was evident for the year-to-date. At the 12-month time scale, dryness dominated from the West to the Midwest, with pockets of dryness in the Southeast and coastal Mid-Atlantic. October 2011-September 2012 ranked in the top ten driest category for eight states, with 14 other states ranking in the driest third of the historical record. Nebraska ranked second driest, with Delaware and Wyoming ranking third driest, for October 2011-September 2012. It should be noted that the dryness this year has been so extreme and persistent that, not only did several states rank driest for several time scales (as noted above), but their records were by wide margins compared to the previous records. The last two years have been so dry that New Mexico has had the driest 24-month October-September period in the 1895-2012 record. The last two years (October 2010-September 2012) have also tied with October 1998-September 2000 as the warmest such 24-month period for New Mexico.

Moisture Stress Index for corn, 1900-2012 Moisture Stress Index for soybeans, 1900-2012


Corn and Soybean Belt

Drought Maps for Selected Months
Year July
Palmer Z Index
August
Palmer Z Index
September
PDSI
1936 X X X
1930 X X X
1901 X X X
2012 X X X

The Primary Corn and Soybean agricultural belt has been especially hard hit by drought this year. The crop Moisture Stress Index (MSI) measures the impact of extreme dryness, as well as excessively moist conditions, on productivity of corn and soybeans by using the Palmer Z Index as an indicator. The MSI is computed annually. It shows the impact of current weather conditions on the productivity of the modern corn and soybean agricultural area compared to how past weather conditions would have theoretically impacted this modern agricultural area's productivity. The 2012 MSI for corn ranked as the fourth worst MSI in the 1900-2012 record, behind 1936, 1930, and 1901. The 2012 MSI for soybeans also ranked as the fourth worst MSI in the 1900-2012 record, behind 1936, 1930, and 1901 as well. The MSI analysis is based on the July-August Palmer Z Index, which reflects moisture conditions during an important part of the growing season. The July and August Palmer Z Index maps, as well as the September Palmer Drought Severity Index map, for these four years can be accessed via the table to the right. In each case, severely dry (short-term drought) conditions afflicted much of the agricultural belt during July and August. The short-term (Palmer Z Index) drought conditions were more important to the productivity of these crops than the longer-term (PDSI) drought conditions.


Western U.S.


Percent area of the Western U.S. in moderate to extreme drought, based on the Palmer Drought Index
Percent area of the Western U.S. in moderate to extreme drought, based on the Palmer Drought Index.

Like the last two months, showers and thunderstorms from the waning summer monsoon brought above-normal rainfall to parts of the Southwest this month, but most of the West was dry, especially from the Pacific Northwest to Northern Rockies where Montana had the driest September on record, Washington ranked second driest, and Oregon third driest. The combination of dryness and well above-normal temperatures resulted in a large area of severe to extreme short-term drought. The rain that fell in the extreme Southwest did little to change the overall percent area in drought. Drier-than-normal weather has dominated much of the West for the water year (October 2011-September 2012), as reflected in low elevation as well as high elevation (SNOTEL) precipitation, especially for the southern half of the West. Reservoir storage was below average, statewide, in most of the western states. Hot, dry, windy weather contributed to many wildfires across the West. According to the USDM, 77 percent of the West was experiencing moderate to exceptional drought at the end of September, a 3 percent increase compared to August. The Palmer Drought Index percent area statistic was about 53 percent, a decrease of two percent compared to last month.

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

SoutheastSouthMidwestNortheastHigh Plains
WestUpper Colorado River BasinPacific Islands

As noted by the Southeast Regional Climate Center, precipitation was highly variable across the region. The driest locations were found along coastal sections of Virginia and South Carolina, where monthly rainfall totals were less than 50 percent of normal. For the second straight month, mean temperatures were near normal across much of the Southeast region. Drought conditions remained fairly stable across the Southeast in September, with approximately one-third of the region classified in drought (D0 and greater) according to the USDM by the end of the month. Wet weather and saturated ground impeded the harvesting of hay, cotton, and peanuts across parts of Alabama, Georgia, and Florida. The planting of sugarcane and winter vegetables was also delayed across parts of Florida due to wet conditions over the past several months. The persistence of wet conditions also contributed to fungal diseases as well as outbreaks of mold and mildew in several different crops across parts of Florida and North Carolina. In contrast, the persistence of dry conditions across central Georgia continued to limit pasture growth.

As explained by the Southern Regional Climate Center, September precipitation in the Southern region varied spatially, with most regions receiving either anomalously high or anomalously low amounts of precipitation. September temperatures in the region were generally at or above normal. Heavy rainfall amounts in the Southern region led to some improvements to drought conditions. In Arkansas, the northeastern counties improved from extreme and exceptional drought to severe drought conditions. Conditions are also improved for much of western Tennessee. Moderate to severe drought conditions were also scaled back in northern Louisiana and southern Arkansas. Elsewhere, drought conditions did not significantly change. Much of Oklahoma and southern Texas remain in extreme drought or worse, while moderate drought conditions are still prevalent in central and western Texas. Texas rainfall has helped mitigate many of the short-term drought effects, as seen in central Texas, where cotton farmers are expecting a 75 percent higher yield than last year and ranchers were provided relief as livestock overhead has been increasing due to rising feed prices. Hydrological improvements of these rains are limited, however. While San Angelo is expecting 50,000+ acre-feet to be recovered to O. H. Ivie Reservoir, Jonestown's lake and reservoir levels are still so low that their revenues from water-sport related purchases are down and have been put in a budget crunch to the tune of $363,000. Ecological impacts are also still being felt, as Longview's forestry service has gone far above budget removing trees killed by lasting drought conditions. The service has already spent nearly $90,000 on tree removal, with an estimated 301 million dead trees still requiring removal (Information Provided by the Texas State Climate Office).

As summarized by the Midwest Regional Climate Center, September precipitation varied drastically from dry in the north to wet in the south. Minnesota recorded its driest September on record (118 years) with many stations recording less than a half inch (13 mm) of rain while precipitation totals in southern Illinois topped 14 inches (356 mm) at several stations. As a percentage of normal, the totals ranged from less than 10 percent to more than five times normal. Heavy September rains in Ohio (4th wettest) and Kentucky (7th wettest) were in contrast to the drier conditions to the north where Minnesota recorded its driest September and Wisconsin had its 9th driest. June to September was the driest on record in Iowa and May to September was the third driest in Missouri. Year-to-date precipitation totals rank among the top 12 driest years since 1895 in five states: Iowa (4th), Illinois (7th), Missouri (8th), Indiana (12th), and Wisconsin (12th). The Midwest regional temperature was slightly below normal in September, breaking a string of 11 straight months above normal from October 2011 to August 2012. For the first time since January 2011, none of the nine Midwest states had an above normal statewide temperature. Drought conditions eased in the southern half of the region but further north there was both expansion and intensification of drought. Overall, the Midwest saw an increase from 82 percent to 91 percent of the region in drought during September but severe drought dropped from 50 to 42 percent and extreme drought dropped from 33 to 15 percent. Missouri saw the biggest improvements going from 97 to just 17 percent areal coverage of extreme drought, though the entire state remained in drought. Minnesota saw the biggest expansion and intensification with drought areas increasing from 38 to 96 percent of the state and extreme drought increasing from 0 to 20 percent. Improvements in the southern parts of the Midwest came too late in the year to help the corn crop. Harvest was on pace or ahead of normal for major crops in the Midwest. Corn harvest was ahead of normal across the region. Soybean harvest was near normal in the southeast but well ahead of normal in the northwest.

As noted by the Northeast Regional Climate Center, overall, the Northeast averaged wetter-than-normal during September. The average monthly temperature of 61.2 degrees F (16.2 degrees C) was 0.4 degrees F (0.2 degrees C) above normal. This is the third month in a row to average warmer than normal. Above normal rainfall during September alleviated drought conditions in much of the Northeast. According to the USDM issued on October 2, 2012, southern Delaware was still experiencing moderate (D1) and severe (D2) drought. Conditions in southern Maryland improved to a mix of D0 and D1, with only a very small D2 area along the border with Delaware. Portions of upstate New York, mainly east of Lakes Erie and Ontario, were still experiencing moderate drought (D1) at month's end.

As explained by the High Plains Regional Climate Center, while most the High Plains region had near normal average temperatures, September 2012 continued to be dry for the majority of the region. Precipitation totals which were less than 50 percent of normal were widespread. In addition, a large area of central and northern South Dakota and pockets of North Dakota, Nebraska, and Wyoming received at most 5 percent of normal precipitation. This dearth of precipitation caused many new records to be set this month. Aberdeen, South Dakota had its driest September on record with only 0.01 inch (0 mm) of precipitation which was 2.18 inches (55 mm) below normal. The old record of 0.05 inch (1 mm) was set back in 1979 (period of record 1893-2012). Interestingly there were numerous stations across South Dakota that received no measurable precipitation this month. One of these locations was Pierre, South Dakota which tied with 1893 for its driest September on record (period of record 1893-2012). The dry weather continued to have an impact across the region. According to the U.S. Army Corps of Engineers, the Missouri River had record low inflows this month of just 0.3 million acre feet. The previous record occurred in 1919 with 0.4 million acre feet (period of record 1898-2012). In addition, water and feed shortages for livestock were common and many producers continued to cull livestock. The dry weather did help with crop dry down and by the end of the month, the corn harvest was well ahead of average in Nebraska and the Dakotas. The only areas of the region which received above normal precipitation were central and southeastern Colorado, and southwestern and eastern Kansas. These areas had precipitation totals ranging from 110 percent of normal to 300 percent of normal.

According to the USDM, there have been significant changes in drought conditions over the last month in the High Plains region. By the end of September, about 99 percent of the region was under moderate (D1) to exceptional (D4) drought, with nearly 24 percent of the region in the D4 designation. In contrast, at the end of last month, only 15 percent of the region was in D4. D4 areas expanded to include most of the state of Nebraska, a small portion of eastern Wyoming, southeastern South Dakota, northeastern Colorado and much of the western and central parts of Kansas. By the end of the month, just over 75 percent of Nebraska was in D4 drought. Extreme drought conditions (D3) also expanded in Nebraska, North Dakota, South Dakota, and Wyoming. In addition, every part of the region had at least some sort of drought designation or either abnormally dry conditions (D0). About the only improvements occurred in eastern Kansas, where the remnants of Hurricane Isaac helped downgrade drought conditions there.

As summarized by the Western Regional Climate Center, continuing this summer's theme of record heat and dry conditions, September 2012 saw above normal temperatures and below normal precipitation for much of the West. Late season monsoon activity over the southern Great Basin and Mojave Desert and a duo of storms hitting south-central Alaska brought locally heavy precipitation, while other locations remained parched. The North American monsoon season (June 15-Sept 30) wrapped up this month, with many locations receiving near or above their normal monsoon precipitation totals. Las Vegas, Nevada received 1.18 in (30 mm) on September 11th, the location's wettest September day on record. The downpours resulted in extensive flooding in the Las Vegas area. The month ranks as the 5th wettest in a record that began in 1937. In northern Arizona, Bagdad received 10 in (254 mm) for the monsoon season, 187 percent of normal for the station. Elsewhere in the region, Prescott and Flagstaff received 76 percent and 100 percent of their average Monsoon precipitation. Albuquerque, New Mexico finished the season at 72 percent of normal. September 2012 was the 5th wettest at Denver, Colorado, with a total of 2.95 in (74.9 mm) of rainfall. It was also the 12th consecutive September with no snowfall in Denver. The other 12-year stretch of no September snowfall occurred from 1914-1926. Precipitation was lacking elsewhere in the West, with many Pacific Northwest locations noting their driest Septembers on record and extended periods with no measurable precipitation. Both Billings and Missoula, Montana received only trace precipitation, their driest Septembers on records beginning in 1934 and 1893, respectively. At Missoula, it was only the second time in the station's history that any month in the year received no measurable precipitation. Sheridan, Wyoming also recorded only trace precipitation in September tying the driest on record. Beginning the 11th of August, 51 consecutive days passed at Sheridan without measurable precipitation, the longest dry period in a record beginning in 1920. In Washington, Spokane, Bellingham, and Olympia all set or tied their driest year-to-date on record. Dry conditions also dominated Hawaii, where Lihue, Kauai, received only 35 percent of its normal September rainfall. Precipitation at Lihue has been below average nine of eleven months of the current water year.

With dry fuels, high temperatures, and low relative humidity prevailing throughout the month, many large wildfires ignited or grew throughout September. Smoke from the fires lead to poor air quality in eastern Washington and Oregon, northern Idaho, western Montana, and Northern California. One of the largest, at 339,110 acres (137,233 hectares) by month's end, was the Mustang Fire on the Idaho-Montana border. The North Pass Fire, 10 miles northeast of Covelo, California, has burned 41,983 acres (16,990 hectares) and consumed 26 structures. The national average of large fire events for 2012 remains at 77 percent of the 10-year average, while acreage burned this year is at 129 percent of the recent average.

Upper Colorado River Basin: As reported by the Colorado Climate Center, the October 2nd NIDIS (National Integrated Drought Information System) assessment for the Upper Colorado River Basin (UCRB) indicated that, for Water Year 2012, most of the UCRB was drier than average. Some parts in central Utah and southwest Wyoming saw above average precipitation for the water year. The San Juan mountains in CO received near average precipitation. Northwest CO was the driest part of the basin, with most areas receiving between 30% and 70% of average water year precipitation. East of the basin, most of eastern CO saw between 70% and 90% of average water year precipitation, with parts of the Front Range, Saguache County, and the Sangre de Cristos receiving near average precipitation for the water year. As of September 30th, about 48% of the USGS streamgages in the UCRB recorded normal (25th - 75th percentile) or above normal 7-day average streamflows. About 35% percent of the gages in the basin are recording much below normal or low (i.e. lowest on record) streamflows (a decrease from 48% one week ago). Only 3% of the gages are recording above normal flows. As flows return to a normal baseflow, the rivers are expected to run lower, and small changes could mean larger changes in percentiles rankings. Accumulated volumes for this time of year is a better indicator of how runoff has been affected by dry conditions. Most of the UCRB and the rest of CO experienced warmer than average temperatures for the month of September. Satellite vegetation conditions show very dry vegetation through much of the northern part of the UCRB and throughout eastern CO. Improved vegetation conditions show up in the central and southern mountains of CO and also in southern UT. For the growing season, reference evapotranspiration (ET) rates were higher than average across the western slope (meaning more available water was being lost to the atmosphere than normal, largely due to the anomalously warm spring and summer). East of the basin, stations in southeast and northeast CO reported near record or record high reference ET accumulations for the growing season. For the month of September, all the major reservoirs in the UCRB saw a volume decrease, which is normal during this time of year. Navajo and Granby reservoirs decreased more than what is normal for this time of year, while Green Mountain decreased less than average. At the end of the month, many of the reservoirs were between 70% and 85% of average. Blue Mesa and Green Mountain are the lowest, at 53% and 60% of average respectively, and Flaming Gorge is the highest, at 97% of average.

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.

As noted by the National Weather Service office in Honolulu, the 2012 Hawaiian Islands dry season has concluded and, as expected, large areas of the state, especially in the leeward areas of Maui County and the Big Island, head into the new wet season under significant drought. Areas of extreme drought, or the D3 category in the USDM map, remain firmly in place. In Maui County, this includes the southwest slopes of Lanai, western Molokai and southwest Maui from Kihei to Makena. On the Big Island, extreme drought continues to cover most of the south Kohala district, the Pohakuloa region of the Hamakua district and the north-facing slopes of Hualalai in the north Kona district. Extreme drought has also redeveloped over the lower elevations of southwest Kau. On Kauai, severe drought, or D2 category conditions, covers the lower elevations from Kealia to Koloa, then westward to Waimea. Maui county D2 conditions include the lower leeward slopes of the west Maui Mountains and the leeward slopes of Haleakala from Kula to Kaupo. On the Big Island, the main area of severe drought persists in the Humuula Saddle. An increase in rainfall over the northeast half of Oahu has reduced the area of moderate drought, or D1 conditions, which is now mainly confined to the leeward sections of the Waianae range.

Some drought impacts impacts in Hawaii include the following:

KAUAI:
NO SIGNIFICANT CHANGES SINCE THE SEPTEMBER 6 UPDATE.  RECENT REPORTS
INDICATED POOR PASTURE CONDITIONS IN THE AREA FROM KALAHEO TO
HANAPEPE.  OTHER AREAS WITH POOR PASTURE CONDITIONS INCLUDE THE
REGION FROM KOLOA TO MAHAULEPU...AND FROM KEALIA TO KALEPA.

OAHU:
PASTURES AND GENERAL VEGETATION REMAIN IN POOR CONDITION OVER THE
LEEWARD WAIANAE RANGE.  REPORTS FROM EARLIER IN THE SUMMER INDICATED
THAT SOME RANCHERS DESTOCKED PASTURES IN THE WAIALUA...MAKAKILO AND
PALEHUA AREAS OF THE ISLAND.

THE WATER SUPPLY IN THE WAIMANALO RESERVOIR REMAINS ABOVE
PRE-DROUGHT LEVELS.  A VOLUNTARY 10 PERCENT REDUCTION IN WATER USE
REMAINS IN PLACE AS A PRECAUTION FOR THE DRY SEASON.

MOLOKAI:
NO SIGNIFICANT CHANGES SINCE THE SEPTEMBER 6 UPDATE.   PASTURES AND
GENERAL VEGETATION CONDITIONS REMAIN VERY POOR WEST OF KAUNAKAKAI.
AN EARLIER REPORT INDICATED THAT THE DRY CONDITIONS HAVE RESULTED IN
AN INCREASE IN AXIS DEER ENCROACHMENTS AND CROP DAMAGE AS THEY SEEK
FOOD AND WATER.

THE WATER LEVEL IN THE KUALAPUU RESERVOIR REMAINS VERY LOW.
THUS...THE STATE OF HAWAII DEPARTMENT OF AGRICULTURE HAS CONTINUED A
MANDATORY 30 PERCENT REDUCTION IN IRRIGATION WATER CONSUMPTION.

LANAI:
A RECENT REPORT FROM LANAI INDICATED THAT THE MIDDLE AND LOWER
ELEVATIONS OF THE ISLAND...ESPECIALLY ALONG THE NORTH-...EAST- AND
SOUTH-FACING SLOPES...REMAIN VERY DRY AND THAT PLANTS AND ANIMALS IN
THESE AREAS HAVE BEEN STRUGGLING TO SURVIVE.  EVEN DROUGHT-RESISTANT
PLANTS AND TREES SUCH AS KIAWE WERE STRUGGLING UNDER THE DRY
CONDITIONS.  MOUFLON SHEEP...AXIS DEER AND GAME BIRD POPULATIONS
HAVE BEEN REDUCED.

MAUI:
SPOTTY LEEWARD RAINFALL IN SEPTEMBER MAY HAVE HELPED PREVENT A
WORSENING OF DROUGHT BUT IT IS TOO SOON TO TELL HOW MUCH OF AN
IMPROVEMENT IT MAY HAVE PRODUCED...IF AT ALL.  THE CURRENT SHORT
TERM DRY TREND OVER THE PAST 2 WEEKS MAY BE NEGATING ANY IMPACTS
THE MID-SEPTEMBER RAINS HAVE GENERATED.  AN EARLIER REPORT
INDICATED THAT UPCOUNTRY AGRICULTURE CONTINUES TO BE SIGNIFICANTLY
IMPACTED BY  THE ONGOING DROUGHT.  MEDIA REPORTS INDICATED THAT
RANCHERS HAVE HAD TO INCREASE IRRIGATION...SUPPLEMENT FEED AND
REDUCE HERD SIZES. ENCROACHING AXIS DEER HAVE ALSO DECREASED FORAGE
FOR LIVESTOCK. BRUSH FIRE RISK...ESPECIALLY ALONG THE SOUTHWEST
SLOPES OF HALEAKALA...IS EXTREMELY HIGH.  THE MAUI COUNTY DEPARTMENT
OF WATER SUPPLY HAS CONTINUED THE ONGOING CALL FOR A 5 PERCENT
REDUCTION IN WATER USE FOR UPCOUNTRY RESIDENTS.  THE REQUEST FOR A
10 PERCENT REDUCTION IN WATER USE BY CENTRAL AND SOUTH MAUI ALSO
REMAINS IN EFFECT.

BIG ISLAND:
THE WORSENING OF DROUGHT IN THE SOUTH POINT AREA HAS FORCED SOME
RANCHERS TO REDUCE HERD SIZES BY 25 PERCENT AND PURCHASE
SUPPLEMENTAL FEED.  NEARBY FLOWER GROWERS HAVE HAD TO SPEND
EXCESSIVE AMOUNTS OF MONEY TO FILL CATCHMENT TANKS FOR IRRIGATION.
IN THE KAU...NORTH KONA...SOUTH KONA AND SOUTH KOHALA
DISTRICTS...THE DROUGHT HAS REDUCED THE AMOUNT OF NECTAR AVAILABLE
FOR BEES AND IS NEGATIVELY AFFECTING THE BEE INDUSTRY. LEEWARD
KOHALA COASTAL PASTURES HAVE BEEN WITHOUT ADEQUATE FORAGE FOR MANY
MONTHS AND RANCHERS HAVE BEEN CONTINUING WITH COSTLY WATER HAULING
AND SUPPLEMENTAL FEED OPERATIONS.

SPI values for seven time periods for Hawaiian Island stations, computed by the Honolulu NWS office.
SPI values for seven time periods for Hawaiian Island stations

On other Pacific Islands (maps — Micronesia, Marshall Islands, basinwide), September was drier than normal for Kwajalein and Majuro, and slightly below normal for Chuuk and Pohnpei, but near to above normal for the rest of the stations. Total rainfall for the last 12 months (October 2011-September 2012) was near to above normal for all stations, except Majuro was trending below normal.


X
  • Percent of Normal Precip
  • Precipitation
  • Normals
Pacific Island Percent of 1981-2010 Normal Median Precipitation
Station NameOct
2011
Nov
2011
Dec
2011
Jan
2012
Feb
2012
Mar
2012
Apr
2012
May
2012
Jun
2012
Jul
2012
Aug
2012
Sep
2012
Oct 2011-
Sep 2012
Chuuk97%136%125%57%181%107%40%173%131%141%169%86%114%
Guam NAS135%83%103%162%94%215%121%224%107%66%179%126%108%
Kapingamarangi57%81%124%109%71%121%102%143%179%146%192%147%111%
Koror12%62%97%36%126%121%120%122%95%88%102%111%82%
Kosrae154%95%174%65%185%60%84%86%99%124%144%109%94%
Kwajalein125%130%84%134%114%84%68%161%117%120%95%57%103%
Lukonor56%154%251%86%124%135%76%106%125%82%73%148%101%
Majuro115%119%91%107%65%194%97%59%81%68%87%67%92%
Pago Pago137%157%75%61%98%131%90%126%115%105%59%195%96%
Pohnpei77%123%110%82%138%98%45%115%100%92%96%90%93%
Saipan140%57%110%77%183%35%33%166%118%77%135%101%105%
Yap101%112%116%33%117%185%89%142%99%84%128%187%111%
Pacific Island Precipitation (Inches)
Station NameOct
2011
Nov
2011
Dec
2011
Jan
2012
Feb
2012
Mar
2012
Apr
2012
May
2012
Jun
2012
Jul
2012
Aug
2012
Sep
2012
Oct 2011-
Sep 2012
Chuuk11.1414.4414.015.7413.138.875.0219.5615.2716.9221.7810.04155.92
Guam NAS15.456.145.246.502.854.453.057.636.636.7426.4215.98107.08
Kapingamarangi4.637.5412.199.946.6113.8213.9117.2424.6820.6515.5714.56161.34
Koror1.397.0410.793.6510.819.038.7914.4916.5416.3613.7213.01125.62
Kosrae16.8313.0728.1110.8923.939.5914.7015.3514.5618.5520.4615.52201.56
Kwajalein14.0014.685.594.223.011.973.5810.828.0811.839.236.1793.18
Lukonor6.3814.0228.347.2211.0612.518.6012.3514.5313.0810.2615.02153.37
Majuro14.6515.9710.378.274.4612.759.145.968.897.5410.157.47115.62
Pago Pago12.6715.919.698.1411.7614.008.4112.156.135.843.1912.73120.62
Pohnpei11.7418.2117.6110.7513.1712.928.3122.9814.8614.2113.6211.27169.65
Saipan14.903.224.231.964.750.660.883.964.266.8617.7310.2473.65
Yap12.329.929.912.116.098.435.0011.1411.9512.7418.9225.19133.72
Pacific Island 1981-2010 Normal Median Precipitation (Inches)
Station NameOct
2011
Nov
2011
Dec
2011
Jan
2012
Feb
2012
Mar
2012
Apr
2012
May
2012
Jun
2012
Jul
2012
Aug
2012
Sep
2012
Oct 2011-
Sep 2012
Chuuk11.5110.6111.2510.107.258.3212.4711.3011.6611.9812.8611.71136.77
Guam NAS11.447.385.114.013.032.072.533.406.1810.1414.7412.6699.09
Kapingamarangi8.199.279.849.159.2711.4313.6412.0813.7814.158.139.93145.85
Koror11.8411.3911.1610.188.567.447.3211.8317.4818.5313.5011.77152.90
Kosrae10.9413.8316.1116.6712.9316.0617.5117.7514.6414.9114.2214.22213.87
Kwajalein11.1811.286.663.162.642.355.266.726.939.879.7410.7490.41
Lukonor11.329.0811.278.418.939.2611.3111.6911.6515.9314.0410.15151.36
Majuro12.7313.4411.397.746.886.589.4210.1111.0111.1711.6911.17125.25
Pago Pago9.2610.1412.8413.3412.0010.689.399.665.335.555.386.53125.57
Pohnpei15.2714.8316.0813.189.5513.1718.4119.9614.8115.4314.2612.55182.36
Saipan10.625.613.852.532.591.892.632.383.628.9113.1310.0970.25
Yap12.188.838.516.395.194.565.637.8512.0415.0814.8213.50120.31

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

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State/Regional/National Moisture Status
A detailed review of drought and moisture conditions is available for all contiguous U.S. states, the nine standard regions, and the nation (contiguous U.S.):

States
alabama arizona arkansas california colorado connecticut
delaware florida georgia idaho illinois indiana
iowa kansas kentucky louisiana maine maryland
massachusetts michigan minnesota mississippi missouri montana
nebraska nevada new hampshire new jersey new mexico new york
north carolina north dakota ohio oklahoma oregon pennsylvania
rhode island south carolina south dakota tennessee texas utah
vermont virginia washington west virginia wisconsin wyoming

Regional
northeast u. s. east north central u. s. central u. s.
southeast u. s. west north central u. s. south u. s.
southwest u. s. northwest u. s. west u. s.

National
Contiguous United States

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Drought Indicators
The following indicators illustrate the drought conditions this month:

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Contacts & Questions
For additional, or more localized, drought information, please visit:

Citing This Report

NOAA National Climatic Data Center, State of the Climate: Drought for September 2012, published online October 2012, retrieved on October 1, 2014 from http://www.ncdc.noaa.gov/sotc/drought/2012/9.