Drought - February 2020

Issued 11 March 2020
Contents Of This Report:
Map showing Palmer Z Index
Percent Area of U.S. in Moderate to Extreme Drought, Jan 1996 to present
California statewide Precipitation, February, 1895-2020

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 March 3, 2020
The U.S. Drought Monitor drought map valid March 3, 2020.

Like last month, the upper-level circulation over the CONUS during February 2020 was very active with numerous short-wave troughs and ridges, and closed lows, which moved quickly west to east across the country. The upper-level systems dragged surface lows and fronts along with them. A strong high pressure ridge remained anchored over the North Pacific off the West Coast. The ridge funneled Pacific weather systems southward across the western CONUS and into the Southwest, from where they moved northeastward across the eastern CONUS. The surface lows and fronts then picked up Gulf of Mexico moisture and spread above-normal precipitation across the South, Southeast, and Ohio Valley. Some of the systems had enough Pacific moisture to give parts of the Southwest and central to northern Rockies above-normal precipitation, but the western ridge and predominantly northwesterly flow at the upper levels kept much of the West, central to northern Plains, and Great Lakes drier than normal for the month. The orientation of the storm track also kept southern Texas and central Florida drier than normal, and the East Coast warmer than normal. Occasionally long-wave ridges and troughs would become established, but the strong North Pacific High and upper-level ridge over the West, with a trough over central to eastern North America, dominated the monthly circulation. Storm systems moving along the top of the North Pacific ridge brushed southern Alaska with above-normal precipitation. Seasonal subtropical trade winds brought dry weather to much of the U.S.-Affiliated Pacific Islands (USAPI), much of Hawaii was drier than normal, and southern portions of Puerto Rico and the U.S. Virgin Islands had below-normal precipitation for the month. As a result of these conditions, drought or abnormal dryness expanded or intensified across much of California, Nevada, southern Oregon, southern Texas, and the USAPI, and in parts of Florida. Drought or abnormal dryness contracted or became less intense in parts of the northern to central Rockies, Four Corners States, southern Plains, and Gulf of Mexico to Mid-Atlantic coasts. Drought expansion was more than contraction this month, with the USDM-based national moderate-to-exceptional drought footprint across the CONUS rising from 11.0 percent of the CONUS at the end of January to 11.5 percent at the end of February (from 9.2 percent to 9.6 percent for the 50 States and Puerto Rico). According to the Palmer Drought Index, which goes back to the beginning of the 20th century, about 9.4 percent of the CONUS was in moderate to extreme drought at the end of February, increasing about 5 percent from the 4.4 percent at the end of January.

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 February, as depicted on the March 3, 2020 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 may show 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 drought occurred across the Far West, expanding and intensifying long-term dry conditions there. Short-term drought occurred in southern Texas and central Florida, continuing long-term drought in those states (PHDI maps for February compared to January). Short-term wet conditions in the Southeast to Mid-Atlantic expanded 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. Dryness is widespread across much of the West Coast states, Nevada, and Utah at the 1-, 6-, and 9-month time scales, with California dry at the 1- to 12-month time scales and parts of the Great Basin dry at the 1- to 9-month time scales. Parts of the Pacific Northwest are dry at the 1- and 6- to 24-month time scales. Parts of Colorado are dry at the 2-, 6-, 9-, and 24-month time scales, with dryness across the Four Corners region at 9 and 24 months. Much of southern Texas is dry at the 1- to 12-month time scales. Parts of Florida are dry at 2 and 6-12 months. Much of the central and northern Plains to Great Lakes is dry at 1 month, with parts of the central to northern Plains dry at 2 to 3 months, but wet conditions dominate at 6-24 months. Southern New England to New Jersey are dry at 2 months, with dryness centered in Delaware and eastern Maryland at the 6- to 12-month time scales. Wet conditions dominate most of the Southeast at all time scales and much of the country east of the Rockies at 6 to 24 months.


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



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 SPEI for current month.
1-month SPI for current month
1-month SPI for current month.

Temperatures during February 2020 were significantly warmer than normal across California. Precipitation in the state was below normal, with large parts experiencing record-dry February conditions. Since this is the middle of winter, the effect of warmer-than-normal temperatures on evapotranspiration is muted so the SPEI and SPI maps show similar conditions (SPEI maps for last 1, 2, 3 months) (SPI maps for last 1, 2, 3 months). However, even though the effect is not as strong as in summer, the warmer-than-normal temperatures of the last 1 to 2 months still resulted in a statewide SPEI value for California that was more extreme than the SPI value (February: SPEI -1.49, SPI -1.38) (January-February: SPEI -1.53, SPI -1.45). The SPEI for February 2020 was the driest in the 1895-2020 record, while the SPI was second driest. For January-February 2020, both the SPEI and SPI were each the driest in their respective records.

72-month SPEI for current month
72-month SPEI for current month.
72-month SPI for current month
72-month SPI for current month.

California, as well as much of the West, has experienced persistent warmer-than-normal temperatures for most of the last 8 years. The cooler- and wetter-than-normal conditions in California for the previous year and the year before that have significantly improved long-term moisture conditions. But the unusual warmth of the recent past has still made the SPEI more extreme than the SPI, both for California (the 60-month SPEI for February 2020 is dry while the 60-month SPI is wet) and across the West (SPEI maps for last 24, 36, 48, 60, 72 months) (SPI maps for last 24, 36, 48, 60, 72 months).



Regional Discussion


Hawaii percent of normal precipitation map, March 2019-February 2020
Hawaii percent of normal precipitation map, March 2019-February 2020.

Hawaii:

February 2020 was drier than normal across much of the Hawaiian Islands. The precipitation anomaly pattern was mixed for the last 2 months, mostly drier than normal for the last 3 to 8 months and 11 months, except for Oahu which had a mixed pattern. Oahu and the Big Island were mostly wetter than normal with the rest of the main islands drier than normal at the 9-month time scale. Hawaii was mostly drier than normal at the 12-month time scale, but wetter than normal at longer time periods (last 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 24, 36, 48, 60 months). Streamflow was mostly near normal. Drought and abnormal dryness contracted during February with the statewide drought area decreasing from 8.1 percent at the end of January to 3.1 percent at the end of February.



Gridded precipitation percentile map for Alaska, December 2019-February 2020
Gridded precipitation percentile map for Alaska, December 2019-February 2020.
Alaska 36-month percent of normal precipitation map, March 2017-February 2020
Alaska 36-month percent of normal precipitation map, March 2017-February 2020.

Alaska:

February 2020 was drier than normal across parts of interior Alaska, with wetter-than-normal conditions along parts of the southern coastal areas. The last 2 to 3 months had a similar pattern, except the dryness was more intense and widespread. Wetter-than-normal conditions dominate much of the state from the 4- to 12-month time scales, except for drier-than-normal conditions in the panhandle and south central coastal areas. At longer time scales, wetter-than-normal conditions dominate except in the panhandle (low elevation station precipitation anomaly maps for the last 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 24, 36, 48, 60 months) (high elevation SNOTEL station precipitation maps for last 1 and 5 months, and SNOTEL basin map for last 5 months) (gridded precipitation percentile maps for the last 1, 2, and 3 months) (climate division precipitation rank maps for the last 1, 2, 3, 6, 12 months) (Leaky Bucket model precipitation percentile map). Temperatures were colder than normal across the northern to central parts of the state during February and colder than normal across most of the state for the last 2 to 4 months. The temperature anomaly pattern transitioned to a mixed pattern at the 5- to 6-month time scales, then warmer than normal across the state at the 12-month time period (low elevation station temperature maps for the last 1, 2, 3, 4, 5, 12 months) (gridded temperature percentile maps for the last 1, 2, and 3 months) (climate division temperature rank maps for the last 1, 2, 3, 6, 12 months) (Leaky Bucket model temperature percentile map). Snow pack was below average in the south central SNOTEL basins and above average elsewhere. Streamflow was near normal at most of the unfrozen streams reporting at this time of year. Abnormal dryness covered 6.2 percent of Alaska on the March 3rd USDM map, basically reflecting long-term dry conditions in the panhandle.



Puerto Rico percent of normal precipitation map for February 2020
Puerto Rico percent of normal precipitation map for February 2020.
Puerto Rico and the U.S. Virgin Islands percent of normal precipitation map for October 2019-February 2020
Puerto Rico and the U.S. Virgin Islands percent of normal precipitation map for October 2019-February 2020.

Puerto Rico and U.S. Virgin Islands:

February was wetter than normal across northern parts of Puerto Rico and the U.S. Virgin Islands (USVI) and drier than normal over some southern and western parts. Wetter-than-normal conditions dominated at the 2- to 3-month time periods, except in northwest Puerto Rico and at some USVI stations. Drier-than-normal conditions dominated across eastern and southern Puerto Rico and the USVI at 4 to 24 months. Wetter-than-normal conditions dominated again at longer time scales (radar-based precipitation anomaly estimates for the last 1, 2, 3, 5, 6, 12 months) (low elevation station precipitation maps for the last 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 24, 36, 48, 60 months). Root zone analyses indicated that soil conditions were still dry along some southern and northwestern coastal areas of Puerto Rico. February streamflow was mostly near to above normal across Puerto Rico. Abnormal dryness shifted from southwest and southeast portions to the northwest part of Puerto Rico on the March 3rd USDM map. In the USVI, moderate drought continued on St. Croix, while St. John and St. Thomas were free of drought and abnormal dryness.



CONUS State Precipitation Ranks:

Map showing February 2020 state precipitation ranks California statewide precipitation, February, 1895-2020

February 2020 was drier than normal across the West Coast to Four Corners region, southern Texas, and central and northern Plains to Great Lakes. Ten states in the West, Plains, and Great Lakes had a rank in the driest third of the 126-year historical record for February, including California which ranked driest on record, North Dakota (11th driest), Minnesota (12th driest), and Iowa and Nevada (both 13th driest).

Map showing January-February 2020 state precipitation ranks California statewide precipitation, January-February, 1895-2020

January-February 2020 was drier than normal in the same areas of the West, Plains, and southern Texas, but also across parts of Florida and southern New England. Twelve states in these regions had a rank in the driest third of the 126-year historical record for January-February, including California which ranked second driest and Rhode Island at 12th driest.

Map showing December 2019-February 2020 state precipitation ranks California statewide precipitation, September-February, 1895-2020

December 2019-February 2020 was drier than normal across parts of the West, Plains, and western Gulf of Mexico coast. Areas of wetter-than-normal precipitation dotted parts of some of the states in these areas. Only four states (in the West) had a rank in the driest third of the 125-year historical record for December-February.

The last six months were drier than normal from much of the West, Texas, and Gulf Coast, and parts of the central Plains and Mid-Atlantic to southern New England. Seven states in these regions had a rank in the driest third of the historical record for September-February, including California which ranked 11th driest.

The last 12 months were drier than normal across parts of the West, Southwest, southern Texas, and northern Florida, with wetter-than-normal conditions dotting these areas, and wetter-than-normal conditions spread across the rest of the CONUS. Only two states — California and Oregon — ranked in the driest third of the historical record for March 2019-February 2020.



Agricultural Belts


Primary Hard Red Winter Wheat Belt precipitation, February, 1895-2020
Primary Hard Red Winter Wheat Belt precipitation, February, 1895-2020.
Primary Hard Red Winter Wheat Belt precipitation, October-February, 1895-2020
Primary Hard Red Winter Wheat Belt precipitation, October-February, 1895-2020.

During February 2020, the Primary Hard Red Winter Wheat agricultural belt experienced near-normal temperatures and a mixed pattern of precipitation anomalies. The month ranked as the 60th wettest and 61st warmest February, regionwide, in the 1895-2020 record.

October marks the beginning of the growing season for the Primary Hard Red Winter Wheat agricultural belt. For October 2019-February 2020, temperatures were mostly near normal with precipitation having a mixed anomaly pattern. The 5-month period ranked as the 49th wettest and 47th warmest October-February, regionwide, in the 1895-2020 record.


As of March 3rd, drought affected approximately eight percent of winter wheat production, ten percent of cattle inventory, seven percent of hay acreage, two percent of spring wheat production, and one percent of corn production. None of the soybean producing areas were in a drought status as of March 3.

As reported by the U.S. Department of Agriculture (USDA), at the end of February, topsoil moisture was short or very short (dry or very dry) across 65 percent of California, 33 percent of Colorado, 22 percent of Kansas, 70 percent of Nevada, 49 percent of New Mexico, and 20 percent of Wyoming; subsoil moisture was short or very short across 60 percent of California, 34 percent of Colorado, 24 percent of Kansas, 60 percent of Nevada, 56 percent of New Mexico, and 21 percent of Wyoming. In New Mexico, 30 percent of the winter wheat crop was rated in poor to very poor condition.


NOAA Regional Climate Centers:


More information, provided by the NOAA Regional Climate Centers and others, can be found below.


As summarized by the High Plains Regional Climate Center, February 2020 was a variable month for the High Plains region, with western and southern areas experiencing generally cooler and wetter conditions and northern and central areas generally experiencing warmer and drier conditions. Above-normal precipitation was observed in western and southern portions of the region where totals were in excess of 150 percent of normal. Elsewhere, across much of the region, below-normal precipitation was observed throughout the month. Large portions of the region received less than 25 percent of normal precipitation for the month of February, with several locations ranking in the top 10 driest Februarys on record. Dry conditions at this time of the year do not translate into large deficits, however. Mountain snowpack remained in generally good shape this month across Colorado and Wyoming. By the end of February, snowpack continued to be at or slightly above normal for most basins in Colorado and Wyoming. Across the Upper Missouri Basin, mountain Snow Water Equivalent (SWE) was still slightly above normal.

Drought conditions continued to gradually improve across western portions of the High Plains region through February. According to the USDM, the area experiencing drought (D1-D4) in the High Plains region decreased slightly from around 12 percent in late January to around 10 percent as of February 25th. The area of the High Plains that had the largest improvement in drought conditions was Colorado, with an 8 percent areal reduction. This month, there was a reduction in abnormally dry conditions (D0), largely due to appreciable snow that fell across western and southern areas. Nearly all of the D0 conditions were removed in Wyoming and only a small portion remained in western Kansas. Moderate drought (D1) also decreased in coverage across southern and western portions of the High Plains region. In Kansas, the small area of D1 conditions across the central portion of the state was removed, with reductions in D1 in Colorado as well. Severe drought (D2) conditions remained unchanged across Colorado through the month of February. Meanwhile, slight improvements occurred over southwestern Kansas by the end of the month, with a small reduction of severe drought (D2) conditions across this area. Exactly 1 percent of the region remained in D2 as of late February. The remainder of the region continued to remain free of drought. In fact, Nebraska and South Dakota have been drought-free since the end of 2018.

As explained by the Southern Regional Climate Center, precipitation values for the month of February were primarily above normal across the Southern region, but dry regions were present, and temperatures varied spatially across the region. Parts of central and southwestern Oklahoma as well as northern, western, and southern Texas received 50 percent or less of normal precipitation. Parts of southern Texas received 25 percent or less of normal precipitation, while parts of southern Texas received 2 percent or less of normal precipitation. In contrast, western, central, and eastern Texas; northern Louisiana, central and southern Arkansas, northern and central Mississippi, and central and eastern Tennessee received 150 percent or more of normal precipitation, while parts of eastern Texas, southwestern Arkansas, northeastern Louisiana, central and northern Mississippi, and central and eastern Tennessee received precipitation 200 percent or more of normal.

At the end of February, drought conditions both improved and deteriorated across the Southern region. Extreme drought conditions persisted across southern Texas, with areas expanding along the southern border and new areas developing in the southeastern part of the state. Severe drought classifications were still present in southern Texas and extreme western Oklahoma, while new areas developed across southern Texas. However, severe drought conditions were removed in eastern and southeastern Texas, reducing the total area experiencing these conditions. Moderate drought classifications decreased across southwestern Oklahoma as well as southeastern and southern Texas, with moderate drought conditions removed completely from central Texas, southwest Arkansas and northwestern Louisiana. There was a decrease in the overall area experiencing abnormally dry conditions, due to the removal of abnormally dry conditions across southwestern Arkansas, northwestern and southwestern Louisiana, and northern Oklahoma. Additionally, the area experiencing abnormally dry conditions decreased across southwestern Oklahoma, southeastern Louisiana, coastal Mississippi, and western, central, northern, and eastern Texas.

As described by the Midwest Regional Climate Center, February precipitation for the Midwest was near normal with drier conditions in the northwest and wetter conditions in the southeast, and February temperatures were largely near normal across the region. According to the USDM, the Midwest has been drought-free throughout the month of February. The drought-free status extends for 16 straight weeks, since early November. The region also has been free of abnormally dry conditions for seven consecutive weeks, since early January.

As noted by the Southeast Regional Climate Center, February precipitation was well above normal in most of the Southeast and temperatures were above average across the region and Puerto Rico. However, unusual dryness was found across most of Florida, where the precipitation values ranged from 90 to less than 50 percent of normal. Drought conditions intensified across portions of Florida. A pocket of severe drought (D2) developed, ringed by an area of moderate drought (D1) and dry conditions (D0), in the north-central Florida Panhandle. Abnormally dry conditions (D0) also expanded through north-central Florida. A pocket of abnormally dry conditions (D0) developed in the northwest portion of Puerto Rico. Citrus groves are running irrigation due to the abnormally dry conditions.

As explained by the Northeast Regional Climate Center, the Northeast had a warmer- and wetter-than-normal February, with the month ranking 11th warmest regionwide since 1895. The USDM released on February 6 showed 2 percent of the Northeast was abnormally dry. This included a small area in eastern Maryland and southern Delaware. Enough rain fell during the following week to erase the dryness. In mid-February, the Northeast became free of abnormal dryness for the first time since July 2019.

As summarized by the Western Regional Climate Center, a second consecutive month of warm and dry conditions across California led to continued deterioration in snowpack conditions across the Sierra Nevada as well as the emergence of drought-related impacts affecting the agricultural sector including decreased water allocations, decreased stock weights, water hauling, and poor rangeland conditions. Statewide, California experienced its driest February on record and its second driest January-February on record. In Arizona and New Mexico, basin-level snowpack conditions declined to below-normal levels by the end of month while further to the north in the central and northern Rockies, mountain snowpack conditions were near-to-above normal with areas of central Colorado experiencing record-breaking snowfall for the month. In Alaska, below-normal temperatures prevailed for a second consecutive month with the state experiencing its coldest February since 1999.

In California, precipitation was well-below normal across the state with areas of central and northern California experiencing record-breaking dryness as a persistent area of high pressure situated over the eastern Pacific Ocean continued to steer storm tracks away from the state. In central and northern California, numerous locations broke records for the driest February including Fresno, Oakland, Redding, Sacramento, San Francisco, San Jose, and Stockton — all received no measurable precipitation for the month. Monthly average temperatures were above- normal across most of the state with the greatest departures observed in the Northern Coast Ranges, Klamath Mountains, and the lower elevations of the Sierra Nevada. By the end of the month, snowpack conditions were at 46% of normal statewide with the regional snow-water equivalent (SWE) breakdown as follows: Northern Sierra/Trinity 51%, Central Sierra 45%, and Southern Sierra 43%. Despite poor snowpack conditions, California's major reservoirs remained near-normal to above-normal with the state's two largest reservoirs, Lake Oroville and Shasta Lake, at 91% and 106% of average, respectively.

In the Pacific Northwest, wetter-than-normal conditions were observed across central Idaho, northeastern Oregon, southeastern Washington, and in the Cascades of western Washington, while the remainder of the region was generally drier than normal. In southern and central Oregon and south-central Washington, precipitation was less than 25% of normal. The dry pattern in southern and central Oregon led to declines in SWE with the Klamath Basin dropping from 82% of median at the beginning of February to 64% by the end of the month while the Deschutes Basin dropped from 89% to 75% of median. In the basins of Washington and Idaho, SWE ranged from 90% to 115% of median by the end of February.

In the Intermountain West, drier-than-normal conditions were observed across most of Utah, northern Arizona, and southwestern Colorado — while wetter-than-normal conditions prevailed across most of Montana and Wyoming, central and eastern Colorado, and southern New Mexico. As of the end of February, region-level (two-Digit HUC) SWE percentage of 1980-2010 median conditions were as follows: Upper Colorado 107%, Lower Colorado 81%, Rio Grande 90%, and Missouri 116%.

In Alaska, colder-than-normal temperatures prevailed across the state in February with the greatest temperature anomalies observed in the North Slope climate division that had its eighth coldest February on record. Precipitation was above-normal across much of the state including Southeast Alaska where the Juneau Airport observed its fifth wettest February on record with 7.78 in (196 mm; 188% of normal). In the Hawaiian Islands, precipitation was generally near-to-above normal across Kauai, Maui, Oahu, and most of the Big Island, with the exception of the windward side that was drier than normal with Hilo Airport logging 5.62 in (143 mm) for the month, 59% of normal. Average temperatures for the winter months (DJF) were above-normal across most of the island chain with Hilo (74.7 F, 23.7 C) and Lihue (74.7 F, 23.7 C) having their warmest winters on record while Honolulu (76 F, 24.4 C) registered its second warmest on record.


U.S.-Affiliated 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), February 2020 was drier-than-normal at Yap, Chuuk, Luchonoch, Kapingamarangi, and Pohnpei; it was wetter than normal at Koror, Saipan, Guam, Kosrae, Kwajalein, Majuro, and Pago Pago.

Monthly precipitation amounts were below the monthly minimum needed to meet most water needs (4 inches in the Marianas and Pago Pago, and 8 inches elsewhere) at most of the stations — Guam and Saipan (in the Marianas); Yap, Ulithi, Woleai, Chuuk, Kapingamarangi, Lukonor, and Nukuoro, (in the FSM); and Ailinglapalap, Jaluit, Kwajalein, Mili, Utirik, and Wotje (in the RMI). February precipitation was above the monthly minimums at the rest of the USAPI stations. The 4- and 8-inch thresholds are important because, if monthly precipitation falls below the threshold, then water shortages or drought become a concern.

In some of the cases where the rainfall was below the monthly minimum threshold, it was above normal. This is because February is the dry season for most of the stations in Micronesia and normals are low. These stations included Guam (normal median is 3.03 inches, February 2020 precipitation was 3.79 inches which is below the 4-inch monthly minimum threshold), Saipan (normal 2.59 inches, this month 2.63 inches), and Kwajalein (normal 2.64 inches, this month 4.12 inches).

The first two months of 2020 were drier than normal across most of Micronesia. Of the primary stations, only Kwajalein and Majuro (in the RMI), and Pago Pago (in American Samoa), had a wetter-than-normal January-February 2020. For December 2019-February 2020, only Chuuk (FSM), Majuro (RMI), and Pago Pago were wetter than normal.


X
  • Percent of Normal Precip
  • Precipitation
  • Normals
Pacific Island Percent of 1981-2010 Normal Median Precipitation
Station Name Mar
2019
Apr
2019
May
2019
Jun
2019
Jul
2019
Aug
2019
Sep
2019
Oct
2019
Nov
2019
Dec
2019
Jan
2020
Feb
2020
Mar-
Feb
Chuuk175%48%42%125%97%125%135%48%87%177%81%37%94%
Guam NAS39%45%77%46%46%135%166%93%214%29%75%125%88%
Kapingamarangi197%127%169%172%110%124%55%142%229%67%83%52%115%
Koror84%94%57%93%81%140%74%118%99%88%20%123%83%
Kosrae143%137%152%103%62%117%69%98%98%62%51%158%88%
Kwajalein52%22%159%69%48%104%92%94%111%99%112%156%88%
Lukonor103%126%32%127%104%96%63%51%66%91%27%33%70%
Majuro102%35%160%103%64%109%105%117%110%114%90%163%104%
Pago Pago107%108%154%117%316%160%81%105%74%140%163%273%130%
Pohnpei143%66%45%159%101%110%155%138%168%132%57%85%108%
Saipan28%35%243%58%76%140%218%169%126%95%60%102%127%
Yap107%52%91%109%81%78%65%70%105%116%23%63%77%
Pacific Island Precipitation (Inches)
Station Name Mar
2019
Apr
2019
May
2019
Jun
2019
Jul
2019
Aug
2019
Sep
2019
Oct
2019
Nov
2019
Dec
2019
Jan
2020
Feb
2020
Mar-
Feb
Chuuk14.566.004.7414.6211.6516.1315.815.559.2619.918.202.69129.12
Guam NAS0.811.152.612.854.6319.9221.0310.5915.761.462.993.7987.59
Kapingamarangi22.5617.3320.4623.6815.5210.115.5011.6721.276.557.604.84167.09
Koror6.246.896.7816.3015.0418.918.7413.9411.299.862.0210.50126.51
Kosrae23.0223.9626.9115.089.1916.619.7810.6913.5510.068.5020.45187.8
Kwajalein1.221.1410.714.764.7710.109.8910.5312.526.623.534.1279.91
Lukonor9.5814.303.7514.8016.6313.476.445.796.0110.232.262.93106.19
Majuro6.743.3416.1411.317.1212.6911.7314.9514.8313.036.9311.19130
Pago Pago11.4710.1714.916.2417.548.605.289.717.4817.9321.7732.73163.83
Pohnpei18.8412.238.9423.5615.6415.7419.4721.0124.9121.177.528.16197.19
Saipan0.530.935.782.116.7318.3221.9917.927.063.641.532.6389.17
Yap4.882.927.1513.1412.2511.588.828.549.309.891.463.2893.21
Pacific Island 1981-2010 Normal Median Precipitation (Inches)
Station Name Mar
2019
Apr
2019
May
2019
Jun
2019
Jul
2019
Aug
2019
Sep
2019
Oct
2019
Nov
2019
Dec
2019
Jan
2020
Feb
2020
Mar-
Feb
Chuuk8.3212.4711.3011.6611.9812.8611.7111.5110.6111.2510.107.25136.77
Guam NAS2.072.533.406.1810.1414.7412.6611.447.385.114.013.0399.09
Kapingamarangi11.4313.6412.0813.7814.158.139.938.199.279.849.159.27145.85
Koror7.447.3211.8317.4818.5313.5011.7711.8411.3911.1610.188.56152.90
Kosrae16.0617.5117.7514.6414.9114.2214.2210.9413.8316.1116.6712.93213.87
Kwajalein2.355.266.726.939.879.7410.7411.1811.286.663.162.6490.41
Lukonor9.2611.3111.6911.6515.9314.0410.1511.329.0811.278.418.93151.36
Majuro6.589.4210.1111.0111.1711.6911.1712.7313.4411.397.746.88125.25
Pago Pago10.689.399.665.335.555.386.539.2610.1412.8413.3412.00125.57
Pohnpei13.1718.4119.9614.8115.4314.2612.5515.2714.8316.0813.189.55182.36
Saipan1.892.632.383.628.9113.1310.0910.625.613.852.532.5970.25
Yap4.565.637.8512.0415.0814.8213.5012.188.838.516.395.19120.31

As measured by percent of normal precipitation, Lukonor and Yap were drier than normal in the short term (February, the year-to-date [January-February], and the last 3 months [December 2019-February 2020]) and long term (last 12 months [March 2019-February 2020]). Kapingamarangi and Pohnpei were drier than normal in the short-term but wetter than normal in the long-term. Guam, Koror, and Kosrae were wetter than normal for February but drier than normal for the other three 3 periods. Chuuk was near to wetter than normal for December-February but drier than normal for the other 3 time periods. Kwajalein was wetter than normal for February and the last 2 months, but drier than normal for the other 2 time periods. Saipan was near to wetter than normal for February and the last 12 months, but drier than normal for the other 2 time periods. Majuro and Pago Pago were wetter than normal for all 4 time periods. As noted earlier, the monthly normal precipitation amount can vary significantly from month to month due to the strong seasonality of equatorial Pacific precipitation resulting from the seasonal migration of the Inter-Tropical Convergence Zone (ITCZ).

Percent of normal precipitation map for December 2019-February 2020 for the Marianas Islands
Percent of normal precipitation map for December 2019-February 2020 for the Marianas Islands.
Percent of normal precipitation map for February 2020 for the Marshall Islands
Percent of normal precipitation map for February 2020 for the Marshall Islands.

In the Marianas Islands, precipitation was drier than normal for most stations during the last one to 5 months, and drier than normal regionwide for December-February and January-February. Wetter-than-normal conditions dominated for the last 6 to 9 months and at the 24-month time scale, with a mixed precipitation anomaly pattern at 11-12 months and 36-60 months (percent of normal precipitation maps for the last 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 24, 36, 48, 60 months). In the Marshall Islands, it was mostly drier than normal at the western stations and wetter than normal at the eastern stations for most time scales (percent of normal precipitation maps for the last 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 24, 36, 48 months).



The USAPI U.S. Drought Monitor drought map valid for the end of February 2020
The USAPI U.S. Drought Monitor drought map valid for the end of February 2020.

According to the February 29th USDM produced for the USAPI, abnormal dryness (D0) and drought had spread across most of Micronesia. Saipan (in the Marianas); Yap, Woleai, and Lukonor (FSM); and Kwajalein, Ailinglapalap, Jaluit, and Majuro (RMI) were experiencing moderate drought (D1). Severe drought (D2) had developed in the northern RMI (Utirik and Wotje). Only three stations in the FSM (Kosrae, Pingelap, and Pohnpei) and Pago Pago were free of drought or abnormal dryness. Storage in the Majuro reservoir slowly declined during the first half of the month, reaching a minimum of 21.2 million gallons by the 15th, which is about 59 percent of maximum. Rain during the last half of the month increased reservoir storage to about 27.6 million gallons by the 29th, but this was only 76.8 percent of maximum which is still below the 80 percent threshold for concern.

The dry conditions during February 2020 gave Lukonor the third driest February in their 36-year record and Nukuoro the sixth driest February in their 38-year record. But the dry February, coupled with dry conditions during earlier months, combined to give Lukonor the driest November-February through April-February. Kapingamarangi had the fourth driest December-February in their 25-year record, Woleai the third driest July-February (27 years) and second driest March-February (24 years), Yap the fourth driest January-February (69 years) and second driest March-February (68 years), and Ailinglapalap the fourth driest April-February (34 years). At the other end of the scale, Pago Pago had the wettest February in their 54-year record. (It should be noted that there may have been an undercatch issue with Jaluit's rain gauge earlier in 2019.)

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 February 2020, September 2019-February 2020 (last 6 months), and March 2019-February 2020 (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 February 2020, September 2019-February 2020, and March 2019-February 2020.
Rank of 1 = driest.
Station Feb 2020
Rank
Feb
No. of Years
Sep 2019- Feb 2020
Rank
Sep- Feb
No. of Years
Mar 2019- Feb 2020
Rank
Mar- Feb
No. of Years
Period of Record
Pago Pago 54 54 50 54 49 53 1966-2020
Saipan 23 40 31 32 29 31 1981-2020
Kapingamarangi 11 33 7 20 13 15 1962-2020
Kosrae 42 54 6 36 12 31 1954-2020
Lukonor 3 36 1 34 2 23 1981-2020
Nukuoro 6 38 7 36 7 35 1981-2020
Pingelap 18 38 MSG 35 MSG 33 1981-2020
Ulithi 16 37 MSG 34 MSG 33 1981-2020
Woleai 15 36 4 31 2 24 1968-2020
Yap 21 69 8 69 2 68 1951-2020
Pohnpei 25 69 59 69 49 68 1951-2020
Chuuk 13 69 20 69 19 68 1951-2020
Guam 34 63 44 63 18 63 1957-2020
Koror 46 69 15 69 8 67 1951-2020
Ailinglapalap 18 37 10 35 6 34 1981-2020
Jaluit 14 37 6 35 2 34 1981-2020
Mili 12 36 31 33 29 32 1981-2020
Utirik 14 19 MSG 9 MSG 3 1985-2020
Wotje 25 37 28 34 21 33 1981-2020
Kwajalein 46 68 28 68 10 67 1952-2020
Majuro 56 66 43 66 32 65 1954-2020

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 the year to date 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 February 2020, published online March 2020, retrieved on March 7, 2021 from https://www.ncdc.noaa.gov/sotc/drought/202002.

Metadata