February 2019 Drought Report

Overview

The upper-level circulation during February was very active with numerous Pacific weather systems moving in the jet stream flow. These systems dropped above-normal precipitation across much of the West, improving the mountain snowpack. Some of the weather systems took a track toward the Great Lakes, spreading above-normal precipitation across the northern Plains to Upper Midwest, while others tracked along cold fronts in the South, leaving above-normal precipitation across the Tennessee and Ohio Valleys to the Atlantic Coast. The precipitation from these systems largely missed the southern Plains and parts of the central High Plains, where the month was drier than normal. A high pressure ridge helped keep the Southeast warmer than normal, but also inhibited precipitation, so the coastal Southeast was also drier than normal. A Kona Low and its associated fronts brought above-normal precipitation to much of Hawaii, while Puerto Rico and the Alaskan panhandle continued to dry out. Like last month, 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 northern Plains, Hawaii, and southern Florida. Abnormal dryness or drought expanded in the southern Plains, parts of Puerto Rico, and the southern panhandle of Alaska. Dry conditions in the U.S.-Affiliated Pacific Islands (USAPI) also expanded drought there. As a result, the USDM-based national moderate-to-exceptional drought footprint across the CONUS contracted from 16.5 percent of the CONUS at the end of January to 11.9 percent of the CONUS at the end of February (from 14.3 percent to 10.7 percent for all of the U.S.). According to the Palmer Drought Index, which goes back to the beginning of the 20^th century, about 4.7 percent of the CONUS was in moderate to extreme drought at the end of February, decreasing a large 13.8 percent from the 18.5 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.

Drought conditions at the end of the month, as depicted on the February 26^th, 2019 USDM map, included the following core drought and abnormally dry areas:

• A large area of abnormal dryness (D0) and drought stretched across the West, from the Pacific Northwest to the Four Corners states. Areas of moderate (D1) to severe (D2) drought were located in the Pacific Northwest and intermountain basin, with moderate to exceptional (D4) drought in the Southwest (Four Corners states). According to the USDM, 26.5 percent of the West was experiencing moderate to exceptional drought at the end of February. This is a big decrease from last month's 41.2 percent. The percent area of the West (from the Rockies to the West Coast) in moderate to extreme drought (based on the Palmer Drought Index) also decreased significantly to 12.4 percent compared to 56.5 percent at the end of January.
• Abnormal dryness to moderate drought expanded in the southern Plains.
• Abnormal dryness to moderate drought expanded in Puerto Rico.
• Moderate to severe drought expanded slightly in the Alaskan panhandle.
• Abnormal dryness to severe drought expanded in the USAPI.
• Severe drought disappeared, and abnormal dryness and moderate drought contracted but persisted, in Hawaii.
• The last pockets of abnormal dryness and moderate drought disappeared in the northern Plains and shrank in southern Florida, but abnormal dryness expanded in the central High Plains and developed along the South Carolina coast.

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.

Used together, the Palmer Z Index and PHDI maps show that short-term wet conditions occurred across much of the West that were in drought at the end of January, significantly shrinking the long-term drought. Short-term dry conditions occurred across parts of southern Texas and much of the coastal Southeast, reducing previous areas of long-term wet spell conditions. Short-term wet conditions occurred across much of the country from the Tennessee Valley and southern Appalachians to Great Lakes and northern Plains, 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.

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 southern Plains and coastal Southeast at the 1- to 2-month time scales, and the central High Plains (Wyoming and Nebraska) at the 1- to 6-month time scales. A strip of dryness can be seen along the southeast Florida coast at the 6- to 9-month time scales. Coastal Washington exhibits dryness at the 1- to 12-month time scales, and other parts of the Pacific Northwest are dry at the 6- to 24-month time scales. The central Rockies have dry conditions at the 9- to 12-month time scales, and dryness lingers across the extreme northern Plains at the 24-month time scales. Much of the West is wet for the last 1 to 12 months, but dryness is still widespread at 24 months.

Regional Discussion

Hawaii:

February was wetter than normal across most of the Hawaiian Islands due to a Kona Low and its associated fronts that lingered in the region for several days (North Pacific surface analysis map for February 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20). But the dryness of the previous months was evident on precipitation anomaly maps for the last 2, 3, 4, 5, and 6 months, especially over the Big Island. Wetter-than-normal conditions tend to dominate at the longer time scales (last 8, 11, 12, 24, 36 months). Streamflow was above normal at most stations. Drought and abnormal dryness contracted on the February 26^th USDM map, with severe drought disappearing and moderate drought shrinking to about 30 percent of the islands.

Alaska:

February was drier than normal across the southeastern quarter of Alaska, from the south coastal and east-central stations to the southern panhandle. The month was wetter than normal to the west and north. This precipitation anomaly pattern held for much of the last six months, except at the higher elevation stations for the water year-to-date. Near- to wetter-than-normal conditions spread across most of the state at the longer time scales, except dryness persisted in the panhandle (low elevation station precipitation maps for the last 1, 2, 3, 4, 5, 6, 8, 11, 12, 24, and 36 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 maps for the last 1, 2, 3, 6, 12 months) (Leaky Bucket model precipitation percentile map for February). Temperatures during February were near to cooler than normal in the southeastern quarter of the state and warmer than normal to the west and north. This pattern held for the last one to three months. Warmer-than-normal temperatures dominated at longer time scales, with record warmth in the west (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 maps for the last 1, 2, 3, 6, 12 months) (Leaky Bucket model temperature percentile map for February). 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 except for a couple streams in the panhandle. Abnormally dry to severe drought conditions continued in the panhandle, with some expansion of the drought area. About 5.8 percent of the state was in abnormally dry to severe drought conditions on the February 26^th USDM map.

Puerto Rico:

February 2019 was drier than normal across most of Puerto Rico, with wetter-than-normal spots in the southwest and along the northeast coast. Drier-than-normal conditions were widespread for the last 2, 3, 5, and 6 months. Soils dried out across more of the island, and some streams had below-normal flow. As seen on the February 26^th USDM map, moderate drought expanded to cover about a third (32.5%) of the island, with abnormal dryness to moderate drought extending across 88 percent of Puerto Rico.

CONUS State Precipitation Ranks:

With above-normal precipitation across much of the CONUS during February, like last month, most of the states had near-average to above-average precipitation ranks. Four states — Texas, Georgia, South Carolina, and Florida — had large enough areas drier than normal to rank in the dry third of the historical record.

Wet conditions dominated for most of the last 12 months, with a few pockets of dryness occurring at different areas of the country at different time scales. Only the three states (Washington, Nebraska, and South Carolina) ranked in the dry third of the historical record for the year to date (January-February 2019); no states were dry for the last three months (December 2018-February 2019); only Washington ranked in the dry third of the historical record for the last six months (September 2018-February 2019); and three states (Colorado, Oregon, and Washington) ranked in the dry third of the historical record for the last 12 months (March 2018-February 2019)

Agricultural Belts

February 2019 was colder than normal across most of 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 57^th driest and 23^rd coldest February, regionwide, in the 1895-2019 record.

October marks the beginning of the growing season for the Primary Hard Red Winter belt. October 2018-February 2019 was wetter and cooler than normal across the region. The 5-month period ranked as the fourth wettest and 36^th coolest October-February, regionwide.

The prolonged wet conditions in the Plains and East have eliminated drought in the corn and soybean producing areas, and recent precipitation has reduced drought in other agricultural areas. As of February 26^th, drought was affecting six percent of hay acreage, six percent of cattle inventory, four percent of winter wheat production, and one percent of spring wheat production. But the dry conditions for the last two months in the southern High Plains have taken their toll on agriculture in Texas and New Mexico. According to the U.S. Department of Agriculture (USDA), as of February 25^th, topsoil moisture was short to very short (dry to very dry) across 67 percent of New Mexico and 42 percent of Texas; subsoil moisture was short to very short across 68 percent of New Mexico and 34 percent of Texas; 47 percent of winter wheat was in poor to very poor condition in New Mexico (the figure was 21 percent for Texas); and 28 percent of the range and pasture was in poor to very poor condition in Texas.

NOAA Regional Climate Centers:

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

As summarized by the High Plains Regional Climate Center, February was cold and snowy across portions of the High Plains, causing many locations to be ranked in the top 10 coldest and snowiest Februaries on record. The mountain snowpack in Wyoming and Colorado has been plentiful thus far this season, and it has helped ease drought conditions in these areas. However, it is yet to be determined how spring runoff may impact low streamflows.

Overall, drought conditions continued to improve throughout the High Plains in February. The area experiencing abnormal dryness or drought (D0-D4) on the USDM decreased from approximately 33 percent to 31 percent from late January to the end of February, while the area in drought (D1-D4) decreased from 17 percent to 14 percent. Widespread improvements in drought conditions occurred throughout Colorado, which has been dealing with drought since late 2017. Frequent storms occurred throughout February, bringing beneficial snowfall to Colorado's southwestern basins where drought was most intense. As a result, exceptional drought (D4) was completely removed, and extreme drought (D3) was nearly eliminated with the exception of extreme southern areas of the state. Plains snowpack has been ample this season as well, which helped improve drought conditions in the Dakotas. Snowy weather in February prompted a reevaluation of conditions, ultimately leading to the removal of moderate drought (D1) in North Dakota and abnormally dry conditions (D0) across both states. Despite overall improvements, degradations in drought conditions occurred as well. D0 was introduced to northern Wyoming, northeastern Colorado, and the Nebraska Panhandle. These areas missed out on abundant precipitation during the winter months, receiving less than 50 percent of normal precipitation.

As explained by the Southern Regional Climate Center, precipitation and temperatures for the month varied spatially across the region. Precipitation was above normal in the northeast part of the region and below normal in the west. Parts of northern, western, southern, central, and eastern Texas; central and southwestern Oklahoma, southwestern and southeastern Louisiana, and coastal Mississippi received 50 percent or less of normal precipitation. Parts of southwestern Oklahoma as well as northern, central, southern, and western Texas received 25 percent or less of normal precipitation. Parts of northern and western Texas as well as extreme southeastern Louisiana received 5 percent or less of normal precipitation. As a result, at the end of February, drought conditions degraded across parts of the Southern region. Moderate drought classifications were still present in parts of extreme western Texas while new areas appeared in northern, central, and southern Texas as well as southwestern Oklahoma. There were no drought conditions in Tennessee, Louisiana, Arkansas, and Mississippi. There was an increase in the overall area experiencing abnormally dry conditions, with areas developing in southern Louisiana while areas expanded in Texas and Oklahoma.

As described by the Midwest Regional Climate Center, February precipitation was well above normal with 2019 ranking as the second wettest February for the Midwest (125 year record starting in 1895), trailing only last February. February temperatures ranged from well below normal in the northwestern states to well above normal in the southeastern states. The wet conditions across the Midwest have saturated soils across the region. With all the moisture in the winter, there has been no drought in the region since the start of the year. February precipitation even wiped out the remaining areas noted as abnormally dry. Having no areas in the region noted as abnormally dry, according to the USDM, has not happened since May 2017 and only two other times in the history of the USDM (since 2000).

As noted by the Southeast Regional Climate Center, overall, temperatures in the Southeast region were above normal this February (excluding Puerto Rico and the U.S. Virgin Islands), especially portions of Florida, southern Georgia, Alabama and the eastern Carolinas. For the month of February, above average precipitation was seen in the northern and western parts of the Southeast region, while below average precipitation was observed across the southern and eastern parts. Small areas of moderate drought (D1) and slightly larger areas of abnormally dry (D0) conditions were present in parts of the Southeast throughout February. Although drought improvement occurred in eastern Florida, it was not enough to keep it out of abnormally dry (D0) conditions. The heavier precipitation in the northern and western parts of the region missed the coastal areas of South Carolina, southern North Carolina and eastern Georgia, leading to an expansion of abnormally dry conditions (D0) there. Puerto Rico's drought conditions only worsened by the end of the month with abnormally dry (D0) conditions expanding, and moderate drought conditions covering more than 32 percent of the commonwealth by the end of the month. The warmer than normal February means that plants are blooming ahead of schedule. In Georgia, livestock producers, field crops, fruit and vegetable growers all noted negative impacts from too much moisture. Florida reported that most seasonal agricultural activities proceeded normally.

As explained by the Northeast Regional Climate Center, the Northeast's average temperature for February was 27.4 degrees F (-2.6 degrees C), 1.2 degrees F (0.7 degrees C) warmer than normal. For the ninth consecutive month, the Northeast was wetter than normal.

As summarized by the Western Regional Climate Center, an active weather pattern persisted throughout the month of February, bringing abundant precipitation, snowfall, and below-normal temperatures to the majority of the West. In conjunction with development of weak El Niño conditions in the equatorial Pacific Ocean, the active storm cycle and its precipitation brought drought relief as well as flooding to many areas. But several locations in eastern New Mexico recorded less than 5% of normal precipitation allowing drought conditions to persist or intensify in the far southeastern corner of the state.

A persistent ridge of high pressure located south of the Aleutian Islands resulted in warmer than average temperatures throughout the western and northern regions of Alaska. Warm conditions rapidly deteriorated sea ice conditions in the Bering Sea. Sea ice was nearly absent south of 64 N latitude by the end of February. Meanwhile, the atypical western position of the high pressure produced below normal temperatures in southeastern Alaska. Precipitation was confined primarily to western and northern Alaska. Central and southeastern Alaska remained well below normal, which has continued the moderate drought conditions in the panhandle.

Several winter storms brought cooler than average temperatures and above average precipitation to Hawaii. In mid-February, a cold storm brought snowfall to all summits on the Big Island. Snow levels were reported as low as 6,200 feet (1890 m).

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 2019 was drier than normal at Koror, Yap, Saipan, Lukonor, Kapingamarangi, Pohnpei, Kosrae, and Majuro, and wetter than normal at Guam, Chuuk, Kwajalein, and Pago Pago.

A tropical disturbance that became Typhoon Wutip brought precipitation to parts of eastern and central Micronesia, with monthly rainfall totals exceeding 8 inches at Chuuk, Nukuoro, Mwoakilloa, Pingelap, Kosrae (FSM); and Ailinglapalap and Mili (RMI). But a dry trade-wind regime otherwise dominated, resulting in a dry month in terms of drought at the rest of the stations in Micronesia — Saipan, Rota (Marianas); Koror (Palau); Yap, Woleai, Fananu, Lukonor, Kapingamarangi, Pohnpei (FSM); and Jaluit, Kwajalein, Majuro, Utirik, and Wotje (RMI). At these stations the February rainfall amounts were 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 Pago Pago in American Samoa, where the South Pacific Convergence Zone produced abundant rain. The 4- and 8-inch thresholds are important because, if monthly precipitation falls below the threshold, then water shortages or drought become a concern.

According to the end-of-February USDM produced for the USAPI, severe drought (D2) has developed at the northern stations of Saipan, Utirik, and Wotje; moderate drought (D1) was occurring in the west at Koror and Woleai and in the east at Majuro; and conditions were abnormally dry (D0) at Yap, Rota, Fananu, Lukonor, Kapingamarangi, Jaluit, and Kwajalein. The reservoir storage at Majuro had declined by the end of the month to 24.2 million gallons, which was only 67.3 percent of maximum capacity, well below the 80 percent threshold indicating concern. According to a March 7 Drought Information Statement issued by the National Weather Service office in Guam, El Niño-like and post-El Niño-like weather has reduced rainfall across parts of Micronesia during the past several months. Some grass fires have occurred in the Marianas, and impacts on vegetation and groundwater supplies are expected in parts of Micronesia if not already occurring.

The dryness in parts of the RMI was significant. Only 0.30 inch of precipitation fell at Utirik in February and 1.91 inches in January. Wotje recorded only 1.18 inches in February and 1.93 inches in January. Other stations reporting less than two inches of rain in February include Saipan (1.54) in the Marianas and Yap (1.57), Dugor (1.69), Gilman (1.41), Maap (1.17), North Fanif (1.68), and Rumung (1.47) in the western FSM. Utirik had the fourth driest February in a data record spanning 18 years, Jaluit had the seventh driest January-February in 36 years of data, and Ailinglapalap had the fourth driest May-February in 33 years of data. In the FSM, Kapingamarangi had the eighth driest February in 32 years of data, Lukonor seventh driest (in 35 years of data), and Yap ninth driest (68 years).

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

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 2019, September 2018-February 2019 (the last 6 months), and March 2018-February 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.

Station	Feb 2018 Rank	Feb No. of Years	Sep 2018- Feb 2019 Rank	Sep- Feb No. of Years	Mar 2018- Feb 2019 Rank	Mar- Feb No. of Years	Period of Record
Jaluit	23	36	MSG	34	MSG	33	1981-2019
Koror	13	68	23	68	MSG	66	1951-2019
Woleai	13	35	5	30	12	23	1968-2019
Yap	9	68	36	68	41	67	1951-2019
Majuro	26	65	12	65	56	64	1954-2019
Mili	22	35	18	32	MSG	31	1981-2019
Ailinglapalap	33	36	11	34	9	33	1981-2019
Pingelap	19	37	MSG	35	MSG	33	1981-2019
Kosrae	22	53	3	35	10	30	1954-2019
Lukonor	7	35	8	33	3	22	1981-2019
Saipan	13	39	21	31	29	30	1981-2019
Pohnpei	23	68	24	68	66	67	1951-2019
Kwajalein	50	67	11	67	65	66	1952-2019
Kapingamarangi	8	32	15	19	12	14	1962-2019
Chuuk	43	68	60	68	52	67	1951-2019
Guam	51	62	43	62	51	62	1957-2019
Nukuoro	12	37	13	35	4	34	1981-2019
Pago Pago	49	53	46	53	43	52	1966-2019
Wotje	13	36	10	33	MSG	32	1981-2019
Utirik	4	18	5	9	3	3	1985-2019

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

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