Drought - January 2019


Issued 12 February 2019
Contents Of This Report:
Map showing Palmer Z Index
Percent Area of U.S. in Moderate to Extreme Drought, Jan 1996 to present
Percent Area of Western U.S. in Moderate to Extreme Drought, Jan 1996 to present

Please note that the values presented in this report are based on preliminary data. They will change when the final data are processed, but will not be replaced on these pages.


National Drought Overview

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Detailed Drought Discussion


Overview


The U.S. Drought Monitor drought map valid January 29, 2019
The U.S. Drought Monitor drought map valid January 29, 2019.

The upper-level circulation during January consisted of a number of Pacific weather systems moving in the jet stream flow across the southern parts of the CONUS, with some taking a track across the Midwest and up along the East Coast. They spread above-normal precipitation across parts of the West and Plains, and across much of the eastern CONUS along and east of the Mississippi River. The long-wave pattern shifted to a ridge over the western CONSU and trough over the east during the last half of the month, which funneled cold and dry Canadian air masses across the country east of the Rockies. In the end, the parts of the country that missed out on the precipitation included parts of the Pacific Northwest, Plains, and a strip along the Gulf of Mexico and Southeast coast, as well as most of Hawaii and parts of Alaska, Puerto Rico, and the U.S.-Affiliated Islands in the western Pacific. The precipitation this month fell on many areas that were in drought, so drought contraction far outweighed expansion. Drought and abnormal dryness contracted across much of the West and parts of the Plains, Northeast, and southern Florida. Abnormal dryness or drought expanded in other parts of the West and southern Plains, parts of Puerto Rico, and much of Hawaii. As a result, the USDM-based national moderate-to-exceptional drought footprint across the CONUS contracted from 21.9 percent of the CONUS at the end of December to 16.5 percent of the CONUS at the end of January (from 18.7 percent to 14.3 percent for all of the U.S.). According to the Palmer Drought Index, which goes back to the beginning of the 20th century, about 18.5 percent of the CONUS was in moderate to extreme drought at the end of January, decreasing about 3.5 percent from the 22.0 percent at the end of December.

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

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






Drought conditions at the end of the month, as depicted on the January 29th, 2019 USDM map, included the following core drought and abnormally dry areas:



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 (as well as wet spell conditions) in some parts of the country than the PHDI map because the meteorological conditions that produce drought and wet spell conditions are not as long-lasting as the hydrological impacts.

Palmer Z Index map Palmer Hydrological Drought Index map

Used together, the Palmer Z Index and PHDI maps show that short-term dry conditions continued in January in the Pacific Northwest over areas that were in drought at the end of December, maintaining or intensifying long-term drought. Short-term near-normal to wet conditions occurred across much of the Southwest, reducing or eliminating previous areas of long-term drought. Short-term near-normal to wet conditions occurred across much of the country from the Plains to East Coast, maintaining or intensifying previous areas of long-term wet conditions.



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

6-month Standardized Precipitation Index

The SPI maps illustrate how moisture conditions have varied considerably through time and space over the last two years. Wet conditions dominate much of the CONUS east of the Rockies at all time scales. As far as dry conditions are concerned, dryness dominates the Pacific Northwest at the 1- to 12-month time scales, and much of Oregon at the 24-month time scale, and the northern to central Rockies from 2 to 12 months. Dryness extends into northern California at 6 to 24 months. Parts of the Southwest are dry at 6 to 12 months, and much of the Southwest is dry at 24 months. Parts of the central Plains and southern High Plains have dry conditions at the 1-month time scale. Parts of southern Florida are dry at 6 months. A large portion of the northern Plains shows dry conditions at the 24-month time scale.


9-month Standardized Precipitation Index 12-month Standardized Precipitation Index 24-month Standardized Precipitation Index



Regional Discussion


Honolulu, HI precipitation, November-January, 1940-2019
Honolulu, HI precipitation, November-January, 1940-2019.

Hawaii:

Drier-than-normal conditions dominated the Hawaiian Islands during the last 1, 2, and 3 months. Honolulu had the fifth driest November-January in the station's 1940-2019 record. October 2018 was wetter than normal across the state, but the severe dryness of the last three months still resulted in widespread below-normal precipitation at the 4-month time scale. Wetter-than-normal conditions are evident at longer time scales (last 6, 7, 10, 12 months). Wet conditions still dominate at the 24- and 36-month time scales, although stations on the Big Island show evidence of drier-than-normal rainfall totals at these time scales. Streamflow was above normal at many stations, but below-normal streamflow was beginning to appear at some stations. Drought and abnormal dryness expanded on the January 29th USDM map, with moderate to severe drought covering about 39 percent of the islands.



Alaska climate division precipitation rank map, February 2018-January 2019
Alaska climate division precipitation rank map, February 2018-January 2019.

Alaska:

February was drier than normal in interior to south coastal Alaska, but wetter than normal in the drought-stricken southern panhandle and in parts of the west and far north. Dryness persists in parts of the interior for the last 2 to 4 months and is evident in the west and panhandle. Wet conditions dominate at longer time scales, except in the panhandle where precipitation deficits become more severe (low elevation station precipitation maps for the last 1, 2, 3, 4, 6, 7, 10, 12, 24, and 36 months) (gridded precipitation percentile maps for the last 1 and 3 months) (climate division precipitation maps for the last 1, 3, 6, 12 months) (Leaky Bucket model precipitation percentile map for January). Temperatures during January were warmer than normal except in the southern and eastern interior regions. Warmer-than-normal temperatures dominated at longer time scales, with record warmth in the west for the last 12 months (low elevation station temperature maps for the last 1, 2, 3, 4, 12 months) (gridded temperature percentile maps for the last 1 and 3 months) (climate division temperature maps for the last 1, 3, 6, 12 months) (Leaky Bucket model temperature percentile map for January). Snow pack was below average in much of the south due to the warmer-than-normal conditions. Streamflow (for those streams that weren't frozen over) was mostly near to above normal. Abnormally dry to severe drought conditions continued in the panhandle. About 5.8 percent of the state was in abnormally dry to severe drought conditions on the January 29th USDM map.



Puerto Rico percent of normal precipitation map, December 2018-January 2019
Puerto Rico percent of normal precipitation map, December 2018-January 2019.

Puerto Rico:

January 2019 was drier than normal in central Puerto Rico to the northern coast and in parts of the southwest, and wetter than normal along the west coast. Drier-than-normal conditions were widespread for the last 2 to 3 months, and still dominated the island at the 4-month time scale (October 2018-January 2019). The central to eastern sections, and the southern coast, were drier than normal at the 6-month time scale. Soils were dry along the southern coast, towards the interior, and in parts of the northwest, and some streams had below-normal flow. As seen on the January 29th USDM map, moderate drought expanded to cover about 9 percent of the island, with abnormal dryness to moderate drought extending across three-fourths (76%) of Puerto Rico.



CONUS State Precipitation Ranks:

Map showing January 2019 state precipitation ranks Map showing February 2018-January 2019 state precipitation ranks

With above-normal precipitation across much of the CONUS during January, most of the states had near-average to above-average precipitation ranks. Those five states with significant areas drier than normal — Oregon, Washington, Idaho, Montana, and Nebraska — ranked in the dry third of the historical record.

This spatial pattern held for most of the last 12 months. Only the three states in the Pacific Northwest ranked in the dry third of the historical record for the last three months (November 2018-January 2019); five states in the Pacific Northwest and northern Rockies ranked in the dry third of the historical record for the last six months (August 2018-January 2019); and six states (all in the West) ranked in the dry third of the historical record for the last 12 months (February 2018-January 2019). Only Oregon had a top ten driest rank, and that was ninth driest February-January.


Agricultural Belts


Primary Hard Red Winter Wheat Belt precipitation, January, 1895-2019
Primary Hard Red Winter Wheat Belt precipitation, January, 1895-2019.
Primary Hard Red Winter Wheat Belt precipitation, October-January, 1895-2019
Primary Hard Red Winter Wheat Belt precipitation, October-January, 1895-2019.

January 2019 was warmer than normal across the Primary Hard Red Winter Wheat agricultural belt, with parts of the region wetter than normal and parts drier than normal. The month ranked as the 46th wettest and 33rd warmest January, regionwide, in the 1895-2019 record.

October marks the beginning of the growing season for the Primary Hard Red Winter belt. October 2018-January 2019 was wetter and cooler than normal across the region. The 4-month period ranked as the second wettest and 53rd coolest October-January, regionwide.


Pacific Islands: The NOAA National Weather Service (NWS) offices, the Pacific ENSO Applications Climate Center (PEAC), and partners provided reports on conditions across the Pacific Islands.

In the U.S. Affiliated Pacific Islands (USAPI) (maps — Federated States of Micronesia [FSM], Northern Mariana Islands, Marshall Islands [RMI], Republic of Palau, American Samoa, basinwide), January 2019 was drier than normal at Koror, Saipan, Kosrae, Kwajalein, Majuro, and Pago Pago, and wetter than normal at Yap, Guam, Chuuk, Lukonor, Pohnpei, and Kapingamarangi.

It was a dry month in terms of drought at Saipan (Marianas); Woleai (FSM); and Ailinglapalap, Jaluit, Kwajalein, Majuro, Utirik, and Wotje (RMI), with rainfall amounts below the minimum thresholds (4 or 8 inches) required to meet most monthly water needs. It was a wet month (above the minimum thresholds) at the rest of the regular reporting stations in the USAPI. The 4- and 8-inch thresholds are important because, if monthly precipitation falls below the threshold, then water shortages or drought become a concern.

The dryness in the RMI was widespread and, in some locations, becoming significant. Ailinglapalap had the fifth driest January in a data record spanning 36 years, and Jaluit was second driest (out of 36 years of data) (although instrument exposure may have contributed some to the low rainfall totals at Jaluit). January 2019 was the eleventh driest January at Wotje (out of 36 years of data) and Utirik (21 years of data) and 16th driest at Kwajalein (67 years). Kwajalein also had the seventh driest September-January (67 years) and Ailinglapalap the seventh driest February-January (33 years). In the FSM, Woleai had the fifth driest September-January (30 years), Nukuoro the fourth driest March-January (34 years), Lukonor the second driest April-January (22 years), and Kosrae the second driest September-January (35 years). At the other extreme, the last 12 months (February 2018-January 2019) were the wettest such 12-month period at Kapingamarangi (out of 14 years of data) and second wettest at Saipan (30 years), Pohnpei (67 years), and Kwajalein (66 years).

As measured by percent of normal precipitation, Kosrae has been drier than normal in the short term (January and the last 3 months [November 2018-January 2019]) and drier than normal in the long term (last 12 months [February 2018-January 2019]). Kwajalein, Majuro, and Saipan have been drier than normal in the short term and wetter than normal in the long term. Koror and Pago Pago were drier than normal for January but wetter than normal for the other two time periods (the 12-month time period was missing for Koror). Guam was drier than normal for the last 3 months, but near to wetter than normal for January and the last 12 months. Lukonor was wetter than normal for January, but drier than normal for the other two time periods. Chuuk, Kapingamarangi, Pohnpei, and Yap were wetter than normal for all three time periods.


X
  • Percent of Normal Precip
  • Precipitation
  • Normals
Pacific Island Percent of 1981-2010 Normal Median Precipitation
Station Name Feb
2018
Mar
2018
Apr
2018
May
2018
Jun
2018
Jul
2018
Aug
2018
Sep
2018
Oct
2018
Nov
2018
Dec
2018
Jan
2019
Feb 2018-
Jan 2019
Chuuk175%131%45%124%143%107%96%158%93%142%76%183%114%
Guam NAS90%68%316%240%88%146%149%183%78%61%152%106%112%
Kapingamarangi222%171%127%92%67%142%67%128%158%223%93%195%121%
Koror105%37%113%92%66%87%N/A63%119%140%111%96%N/A
Kosrae147%181%105%136%74%106%159%65%34%58%49%93%86%
Kwajalein159%662%229%332%227%90%193%81%63%107%99%49%148%
Lukonor106%84%56%61%67%123%83%96%89%78%70%148%77%
Majuro120%343%189%216%151%142%102%94%67%69%112%93%130%
Pago Pago271%60%189%96%61%192%181%132%128%117%176%83%124%
Pohnpei219%440%102%85%92%130%166%93%100%74%100%134%134%
Saipan87%49%332%384%161%88%146%172%90%83%137%70%132%
Yap163%270%67%94%97%105%100%109%46%136%125%249%111%
Pacific Island Precipitation (Inches)
Station Name Feb
2018
Mar
2018
Apr
2018
May
2018
Jun
2018
Jul
2018
Aug
2018
Sep
2018
Oct
2018
Nov
2018
Dec
2018
Jan
2019
Feb 2018-
Jan 2019
Chuuk12.7010.865.6014.0116.6712.7712.3318.5510.6615.028.5318.49156.19
Guam NAS2.721.407.998.155.4214.8421.8923.178.874.517.754.24110.95
Kapingamarangi20.5919.6017.3911.089.1720.155.4712.6712.9820.719.1317.87176.81
Koror9.032.758.2510.9111.6016.19N/A7.3714.1215.9212.379.79N/A
Kosrae19.0329.0018.4524.1610.7715.8322.609.193.708.097.9215.58184.32
Kwajalein4.2015.5512.0522.3315.758.8818.818.657.0512.126.581.54133.51
Lukonor9.507.766.287.147.8319.6611.709.7910.067.127.8912.41117.14
Majuro8.2922.5417.7921.8116.6215.8811.9610.468.539.2912.717.23163.11
Pago Pago32.476.3617.769.263.2410.689.768.6011.8311.9022.5911.10155.55
Pohnpei20.9457.9218.8016.9113.5820.1123.6111.7015.3110.9716.1317.68243.66
Saipan2.250.938.729.145.837.8819.1217.399.594.645.281.7692.53
Yap8.4412.293.807.4111.6715.8114.8214.655.5612.0310.6815.90133.06
Pacific Island 1981-2010 Normal Median Precipitation (Inches)
Station Name Feb
2018
Mar
2018
Apr
2018
May
2018
Jun
2018
Jul
2018
Aug
2018
Sep
2018
Oct
2018
Nov
2018
Dec
2018
Jan
2019
Feb 2018-
Jan 2019
Chuuk7.258.3212.4711.3011.6611.9812.8611.7111.5110.6111.2510.10136.77
Guam NAS3.032.072.533.406.1810.1414.7412.6611.447.385.114.0199.09
Kapingamarangi9.2711.4313.6412.0813.7814.158.139.938.199.279.849.15145.85
Koror8.567.447.3211.8317.4818.5313.5011.7711.8411.3911.1610.18152.90
Kosrae12.9316.0617.5117.7514.6414.9114.2214.2210.9413.8316.1116.67213.87
Kwajalein2.642.355.266.726.939.879.7410.7411.1811.286.663.1690.41
Lukonor8.939.2611.3111.6911.6515.9314.0410.1511.329.0811.278.41151.36
Majuro6.886.589.4210.1111.0111.1711.6911.1712.7313.4411.397.74125.25
Pago Pago12.0010.689.399.665.335.555.386.539.2610.1412.8413.34125.57
Pohnpei9.5513.1718.4119.9614.8115.4314.2612.5515.2714.8316.0813.18182.36
Saipan2.591.892.632.383.628.9113.1310.0910.625.613.852.5370.25
Yap5.194.565.637.8512.0415.0814.8213.5012.188.838.516.39120.31

The following analysis of historical data for the USAPI stations in the Global Historical Climatology Network-Daily (GHCN-D) dataset, augmented with fill-in data from the 1981-2010 Normals, helps put the current data into historical perspective by computing ranks based on the period of record. The table below lists the precipitation ranks for January 2019, September 2018-January 2019 (the last 5 months), and February 2018-January 2019 (the last 12 months). Some stations have a long period of record and their dataset is fairly complete, while other stations have a shorter period of record and the dataset has some missing data.

Rank, Number of Years with data, and Period of Record for USAPI stations for January 2019, September 2018-January 2019, and February 2018-January 2019.
Rank of 1 = driest.
Station Jan 2018
Rank
Jan
No. of Years
Sep 2018- Jan 2019
Rank
Sep- Jan
No. of Years
Feb 2018- Jan 2019
Rank
Feb- Jan
No. of Years
Period of Record
Jaluit 2 36 1 34 MSG 33 1981-2019
Koror 37 68 35 68 MSG 66 1951-2019
Woleai 20 37 5 30 11 23 1968-2019
Yap 64 68 48 68 50 67 1951-2019
Majuro 27 65 14 65 58 64 1954-2019
Mili 17 35 18 32 MSG 31 1981-2019
Ailinglapalap 5 36 8 34 7 33 1981-2019
Kosrae 23 49 2 35 11 29 1954-2019
Lukonor 26 35 7 33 3 22 1981-2019
Saipan 10 39 23 31 29 30 1981-2019
Pohnpei 55 68 32 68 66 67 1951-2019
Kwajalein 16 67 7 67 65 66 1952-2019
Kapingamarangi 27 29 19 19 14 14 1962-2019
Chuuk 66 68 62 68 51 67 1951-2019
Guam 28 62 36 62 46 61 1957-2019
Nukuoro 13 37 15 35 8 34 1981-2019
Pago Pago 21 53 37 53 47 52 1966-2019
Wotje 11 36 12 33 MSG 32 1981-2019
Utirik 11 21 6 10 4 4 1985-2019

Precipitation amount for current month for U.S. Affiliated Pacific Island stations

Percent of normal precipitation for current month for U.S. Affiliated Pacific Island stations

Percent of normal precipitation for last 3 months for U.S. Affiliated Pacific Island stations

Percent of normal precipitation for last 12 months for U.S. Affiliated Pacific Island stations

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

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: Drought for January 2019, published online February 2019, retrieved on February 24, 2019 from https://www.ncdc.noaa.gov/sotc/drought/201901.

Metadata