Issued 13 April 2023

March 2023 Palmer Z-Index
U.S. Percent Area Wet or Dry January 1996 - March 2023
March 2023 /monitoring-content/sotc/drought/2023/03/md-p-reg018dv00elem01-01032023.gif

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 Highlights

Detailed Drought Overview

The atmospheric circulation over North America continued to be very active during March 2023. Numerous upper-level shortwave troughs and closed lows moved through the jet stream flow throughout the month, dragging Pacific fronts and surface lows with them. During the first part of the month, the upper-level systems favored the western CONUS, creating and reflecting what is called a long-wave trough in the jet stream flow, with a compensating ridge over the East. The circulation pattern flattened (became more zonal), then the upper-level systems began favoring the central to eastern CONUS, causing the long-wave trough to shift east at mid-month. During the latter part of the month, the upper-level systems favored the West again, shifting the long-wave trough back to the west with a ridge extending over the East. This pattern fed Pacific moisture to the West in several "atmospheric rivers", resulting in a much-wetter-than-normal month for most of the West. The fronts and surface lows tapped Gulf of Mexico moisture to spread above-normal precipitation across eastern Oklahoma to the Great Lakes, with snow falling in the below-freezing air along the northern tier states. They also triggered waves of severe weather, from Texas to Florida and from the Gulf of Mexico to the southern Great Lakes. The weather systems were dried out as they crossed the Rockies, resulting in a drier-than-normal month for most of the Plains. The storm track missed northern portions of the Pacific Northwest, the Gulf of Mexico Coast, and much of the East Coast, which all ended up with a drier-than-normal March. When averaged across the month, the circulation pattern ended up with an anomalous trough over the West and ridge centered over the Southeast extending northward along the East Coast. The monthly temperature anomaly pattern reflected this, with below-normal monthly temperatures from the West Coast to Upper Mississippi Valley and above-normal monthly temperatures across the Gulf of Mexico and East Coasts.

The above-normal precipitation resulted in contraction or reduction of the intensity of drought over large parts of the West, as well as parts of the Plains, Great Lakes, and Southeast. But areas experiencing a drier-than-normal month saw drought expansion or intensification. These areas included parts of the Pacific Northwest, southern to central Plains, Florida, and Mid-Atlantic Coast, as well as Puerto Rico and part of Hawaii. Drought contraction greatly exceeded expansion with the USDM-based national moderate-to-exceptional drought footprint across the CONUS decreasing from 38.5% at the end of February to 28.2% at the end of March (from 32.1% to 23.6% for the 50 states and Puerto Rico). According to USDM statistics, the atmospheric rivers since October have dumped so much precipitation across the country — especially the West where much of the improvement has occurred — that the CONUS USDM percent area in moderate to exceptional drought fell from a peak coverage of 63.0% on October 25, 2022 to 28.2% on April 4, 2023. The only other time that the CONUS drought area topped 60% (in 2012, reaching 60.8% on July 10 and peaking at 65.5% on September 25), it took more than two years to fall below 30% (on October 14, 2014).

According to the Palmer Drought Index, which goes back to the beginning of the 20th century, about 20.6% of the CONUS was in moderate to extreme drought at the end of March, which is a slight increase compared to the end of February.

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Drought conditions at the end of March, as depicted on the April 4, 2023 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.

March 2023 Palmer Z-Index
March 2023 PHDI

Used together, the Palmer Z Index and PHDI maps show that short-term drought occurred in the Mid-Atlantic, Southeast, and southern to central Plains, expanding or intensifying long-term drought (PHDI maps for March compared to February). Short-term wet conditions occurred in eastern Oklahoma to the southern Great Lakes and over parts of the northern Plains, eliminating long-term drought and beginning or expanding areas of long-term wet conditions. Short-term wet conditions also occurred across much of the West, shrinking long-term drought in the Pacific Northwest and expanding and intensifying long-term wet conditions in areas to the south.

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.

March 2023 SPI
February-March 2023 SPI
January-March 2023 SPI
October 2022-March 2023 SPI

The SPI maps illustrate how moisture conditions have varied considerably through time and space over the last two years. Dryness is evident across parts of the central to southern Plains at all time scales, and is especially widespread and intense at the 9- to 24-month time scales. Parts of the northern Plains are dry at 3, 9, and (in the Montana Plains) 24 months. The Mid-Atlantic region is dry at 1 to 3 months, with parts of the Mid-Atlantic Coast dry at the longer time scales. Parts of New England are dry at 1 and 2 months. The Pacific Northwest has dryness in some parts at all time scales, with the most widespread and intense dryness occurring at the 3-, 9-, and 24-month time scales. Parts to much of the Gulf of Mexico Coast region are dry at 1 to 6 months. Much of the West is wet at 1 to 12 months, with parts of California and the Southwest wet even at 24 months. The region from eastern Oklahoma to the Great Lakes is wet at 1 to 3 months, with parts of this region wet at longer time scales. At the 24-month time scale, it is wet from the central Gulf of Mexico Coast to the Great Lakes and New England.

July 2022-March 2023 SPI
April 2022-March 2023 SPI
April 2021-March 2023 SPI

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.

For the Northern Hemisphere, March is the beginning of climatological spring, which is the season when evapotranspiration is beginning to increase with rising sun angle and longer days. During March 2023, temperatures were warmer than normal across the Gulf Coast and up the East Coast, but cooler than normal across the West, central to northern Plains, and Mid- to Upper Mississippi Valley. The Gulf and Mid-Atlantic Coasts were drier than normal, with the most severe dryness occurring in the Mid-Atlantic and in central Florida, but it was also severely dry in parts of the central to southern Plains. The 1-month SPEI was a little more severe than the corresponding SPI in central Florida, but the SPEI and SPI were about equally severe in the Mid-Atlantic, while the colder-than-normal temperatures in the central Plains made the SPI more severe than the SPEI. The first three months of the year had record warm temperatures from Virginia to Florida. This was enough to make the January-March SPEI more severe than the corresponding SPI in the Mid-Atlantic, Florida, and southern Texas, where the period was also drier than normal. The last six months were acutely drier than normal in the central to southern Plains, especially southwest Kansas to the Texas panhandle, but this area was also mostly cooler than normal, so the October-March SPEI was less severe here than the corresponding SPI (SPEI maps for the last 1, 2, 3, 6, 9 months) (SPI maps for the last 1, 2, 3, 6, 9 months).

The last ten to 20 years have been a period of unusually warm temperatures across the West, especially during the warm half of the year (April-September) but also during the cold half of the year (October-March) (this year has seen a return to cooler temperatures). There have also been periods of extreme dryness westwide during this period (this year also being an exception for precipitation). The combination of excessive heat and dryness has resulted in more extreme SPEI values than SPI values for the last six years (SPEI maps for last 12, 18, 24, 30, 36, 48, 60, 72 months) (SPI maps for last 12, 18, 24, 30, 36, 48, 60, 72 months).

This has especially been the case for California and Oregon, but also Texas in the southern Plains where excessive heat was widespread last year. While the recent precipitation has knocked SPEI ranks out of the most-extreme-on-record category, the SPEI values are still more extreme than the corresponding SPI values for the following states and time scales:

Regional Discussion

Western United States

The current wet season (October-March) has been unusually wet for much of the West (surface station percent of normal precipitation maps for the last 1, 3, 6, 12 months) (high elevation SNOTEL station and basin percent of normal precipitation maps for the last 1, 6, 12 months). Pacific weather systems, fed by more than two dozen atmospheric river events, have brought record to near-record precipitation (SNOTEL station precipitation percentile maps for the last 1, 6, 12 months), with record to near-record mountain snowpack, to areas from California to the Rocky Mountains. Many reservoirs, especially in California (California reservoir maps 1, 2, 3), were refilled and streamflow was much above normal to record high for March (Utah reservoirs; Southwest reservoir maps 1, 2, 3, 4, 5, 6, 7, 8, 9, 10). The combined water storage in the reservoirs plus snowpack in California was excessive. By some measures in some areas, groundwater has recovered, but by other measures in other areas, it is still below average.

The weather systems missed other parts of the West, especially northern portions. Some atmospheric rivers early in the wet season brought precipitation to coastal parts of the Pacific Northwest, but most of this region has been drier than normal, especially for January-March. Soil moisture was still dry in some areas (soil moisture map 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) and groundwater, many reservoirs (Oregon map 1, 2, 3, 4; Idaho map 1, 2, 3), and March streamflow continued low, with some record-low March streamflow values in Washington.

Based on the USDM, the percent area of the western U.S. in moderate to exceptional drought fell to 30.9% at the end of March. The western U.S. has not been free of drought or abnormal dryness for virtually the entire 23-year history of the USDM — the smallest percent area in drought or abnormal dryness was 12.3% on June 11, 2019. Based on the Palmer Drought Index, about 6.8% of the western U.S. was experiencing moderate to extreme drought at the end of March. This is a decrease compared to the end of February, is based on the Palmer Drought Severity Index (PDSI), and reflects the continued wet circulation pattern. The PDSI is a meteorological drought index. The Palmer Hydrological Drought Index (PHDI) is a hydrological drought index that reflects hydrological conditions instead of changes in atmospheric circulation. The PHDI shows a little more drought remaining across the West than does the PDSI. Like the USDM, the Palmer Drought Index shows that much of the West has been in drought for the last 23 years. Since the Palmer data go back to the beginning of the 20th century, they also show that the last two decades have had a greater spatial extent of persistent drought in the West than any other decades in the last 123 years.

Regionwide, the western U.S. (Rockies to West Coast) had the eighth wettest March in the 1895-2023 record, 22nd wettest January-March, 24th wettest water year to date (October-March), and 21st wettest April-March 12-month period. The precipitation of the last 12 months was enough to balance the deficits of the previous 12 months, so that the 24-month April-March period (April 2021-March 2023) ranked as the 63rd driest (65th wettest) such 24-month period in the 129-year historical record. But previous years were so dry that, even with wet conditions for the last 12 months, the last 3 years (April 2020-March 2023) still ranked as the 13th driest such 36-month period, regionwide. The last 12 months have also seen a departure from the unusual heat of recent decades. March 2023, January-March 2023, and October 2022-March 2023 have all been cooler than average, regionwide, while April 2022-March 2023 still ended up on the warm side of the long-term average.

Great Plains

Eastern and northern parts of the Great Plains received above-normal precipitation in March while other parts were dry. The central to northern Great Plains have been wetter than normal at the 3- to 4-month time scales, while southern parts were dry. Previous months have been quite dry, especially the last three years. This is reflected in a number of indicators, including soil moisture, groundwater, streamflow, vegetative health, lack of rain days, consecutive number of dry days, and (especially in the core dry areas) reports of poor crops and ponds going dry.

The area from southwest Kansas to the Texas panhandle has been the epicenter of dryness in the Great Plains in recent months and for the last 2 to 3 years. The Southwest Kansas climate division (division 7) had the driest 18-month, 24-month, and 30-month periods through March 2023, and the Oklahoma panhandle (climate division 1) had the driest 18-month period, based on the SPI. The PHDI for the Texas panhandle (climate division 1) recently reached values as dry as the 1950s drought, although the record dry PHDI values occurred during 2012. The PHDI for the Oklahoma panhandle (climate division 1) has reached very low values, although they are not as low as the 1930s and 1950s droughts or even the 2012 drought.

As of the end of March, 41.3% of the Great Plains region was affected by moderate to extreme drought, based on the PDSI. This is an increase from the 31.7% at the end of February. The recent drought, at its peak last year, was as expansive as the drought of the 1950s.

Regionwide, the Great Plains had the 48th driest March in the 1895-2023 record, 59th wettest January-March, 59th wettest October-March, 20th driest April-March 12-month period, 17th driest April-March 24-month period, and ninth driest April-March 36-month period (tied with April 1935-March 1938). While the last three years have been very dry, the integrated dryness has not been as severe and widespread, regionwide, as the 1930s and 1950s droughts.

Hawaii

March 2023 was mostly drier than normal across most of the Hawaiian Islands except for some wetter-than-normal stations on the Big Island and a few places on the other main islands. The month was also warmer than normal. The last 2 months were drier than normal on Maui and Molokai but wetter than normal on the other main islands. Wetter-than-normal conditions dominated at the 3- to 4-month time scales. Oahu and the windward side of the Big Island were drier than normal at the 6- to 12-month time scales, with drier-than-normal conditions more widespread at 24 to 48 months. A mixed pattern was evident at 60 months (precipitation anomaly maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months) (climate engine model percent of normal precipitation map for the last month).

Monthly streamflow was mostly near normal. There was little to no stress on vegetation this month based on satellite analyses (stressed vegetation, drought risk, VHI).

A small (1.2%) area of moderate drought returned to Maui and abnormal dryness covered 15.3% of Hawaii, as seen on the April 4, 2023 USDM map.

Alaska

March 2023 was drier than normal in the south coastal and panhandle regions and a few locations in the Aleutians and in the east central and north coastal regions. At the 2- to 3-month time scales, dryness was centered in the Northwest Gulf and Cook Inlet areas. Drier-than-normal conditions continued along the south coastal and some panhandle areas at 6 to 12 months, with some eastern interior locations drier than normal at 12 months. Wetter-than-normal conditions dominated at longer time scales except for persistent dryness in the Cook Inlet area (low elevation station precipitation anomaly maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months) (high elevation SNOTEL basin percent of normal precipitation maps for the last 6 months) (high elevation SNOTEL station precipitation percentile maps for the last 1, 6, 12 months) (SNOTEL basin and station percent of normal precipitation maps for the last 1, 6, 12 months) (climate division precipitation rank maps for the last 1, 3, 6, and 12 months) (climate engine model percent of normal precipitation map for the last month) (Leaky Bucket model precipitation percentile map).

March temperatures were cooler than normal in the panhandle to warmer than normal in the north and west. Cooler-than-normal temperatures dominated at 2 months. At the 3- to 6-month time scales, warmer-than-normal temperatures dominated except in the far southeast. Warmer-than-average temperatures dominated at for the last 12 months (low elevation station temperature anomaly maps for the last 1, 2, 3, 4, 6, 12 months) (climate division temperature rank maps for the last 1, 3, 6, and 12 months) (gridded temperature percentile maps for the last 1 and 3 months) (Leaky Bucket model temperature percentile map).

The winter snowpack covered the state and was near to above average in most basins. Snow water content (SWE) was near to above normal except for some SNOTEL stations in the south central area (satellite-based estimates of snow depth and SWE; SNOTEL station SWE percentile; SNOTEL basin percent of normal SWE; SNOTEL station and basin percent of normal SWE). Monthly streamflow was mostly near to above normal for those streams that were not frozen.

Alaska was free of drought and abnormal dryness on the April 4, 2023 USDM map.

Puerto Rico and U.S. Virgin Islands

March 2023 and February-March were drier than normal across much of Puerto Rico (PR) and the U.S. Virgin Islands (USVI). The last 3 months had parts of PR wetter than normal, while northwestern and southern parts of PR were drier than normal as was most of the USVI. Drier-than-normal conditions dominated at the 4-month time scale over both PR and the USVI, but the 6-month time scale was wetter than normal over most of PR and continued drier than normal over the USVI. It was wetter than normal over both at 9 months. The USVI were drier than normal at 12 to 24 months with a mixed anomaly pattern over PR. Drier-than-normal conditions dominated both at longer time scales (radar-based precipitation anomaly estimates for the last 1, 2, and 3 months) (low elevation station precipitation maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months) (climate engine model percent of normal precipitation map for the last month: PR and USVI, Caribbean and Gulf of Mexico region).

Root zone analyses indicated that soil conditions were moist across northeastern and interior portions of PR, but dry along the southern and northwest coasts of PR (root zone soil saturation fraction); satellite-based analyses indicated that top layers of the soil were dry across the USVI and PR, and deeper soils were drying out (relative soil moisture at 0-10 cm [0-4 in], 10-40 cm [4-16 in], 40-100 cm [16-39 in], 100-200 cm [39-79 in] depth; SMOS soil moisture anomaly). Satellite analyses showed a growing area of vegetative stress due to drought (VHI for PR and USVI, drought risk for PR and USVI, stressed vegetation for PR and USVI). Monthly streamflow on PR showed below-normal streams over the eastern fourth of the island with a mixed streamflow anomaly pattern in other areas. In the USVI, for the most part, groundwater steadily declined during March at St. Croix and St. John, and held steady at first then declined at St. Thomas. The end-of-March groundwater level was in mid-range (below previous peaks and above recent low levels) on all three islands (St. Thomas, St. Croix, St. John).

According to information summarized by NIDIS (National Integrated Drought Information System), there were reports of soil cracking, dried and brown grass, and a decreasing trend in water levels at reservoirs, rivers, and aquifers across Puerto Rico. In some regions, the reduced rainfall was leading to low soil moisture, dry pastures, and affected crops. Vegetation was beginning to show signs of distress on the USVI, and heat stress has resulted in reduced egg production according to poultry farmers.

In the USVI, severe drought developed on St. Croix, moderate drought continued on St. Thomas, and abnormal dryness developed on St. John. Moderate drought developed to cover about 45.0% of PR on the April 4, 2023 USDM map, while abnormal dryness and moderate drought expanded to cover 74.4% of the territory.

CONUS State Precipitation Ranks

March 2023 was drier than normal in the central to southern Plains, Mid-Atlantic region, along the Gulf of Mexico Coast, and in parts of the Pacific Northwest. Fourteen states had a precipitation rank in the driest third of the 129-year historical record for March, including one that ranked in the top ten driest category — Virginia (eighth driest) — plus two that were close — Delaware and Maryland (both 11th driest).

January-March 2023 was drier than normal in essentially the same areas as March, except the dryness was not as extensive in the southern Plains, was more extensive in the Pacific Northwest, and included parts of the northern Plains. Eleven states had a precipitation rank in the driest third of the 129-year historical record for January-March, including two that ranked in the top ten driest category — Maryland (third driest) and Delaware (fifth driest).

October 2022-March 2023 was drier than normal in the central to southern Plains, Gulf Coast, Mid-Atlantic, Pacific Northwest, and parts of the northern Plains and Ohio Valley. Seven states had a precipitation rank in the driest third of the historical record for October-March, but none ranked in the top ten driest category. Conditions were very dry from southwest Kansas to the Oklahoma panhandle, but wet conditions in other parts of this region prevented these states from having a top ten driest rank.

April 2022-March 2023 was drier than normal in across the central to southern Plains and in parts of the Gulf Coast, Mid-Atlantic Coast, and Pacific Northwest. Seven states had a precipitation rank in the driest third of the historical record for April-March. None ranked in the top ten driest category, but one was close — Nebraska (eleventh driest).

Agricultural Belts

During March 2023, the Primary Hard Red Winter Wheat agricultural belt was mostly drier and cooler than normal. The month ranked as the 6th driest and 60th coolest March, regionwide, in the 1895-2023 record.

October marks the beginning of the growing season for the Primary Hard Red Winter Wheat belt. October 2022-March 2023 also was mostly drier than normal with cooler-than-normal temperatures in the northwest and warmer-than-normal temperatures in the south. The period ranked as the 44th driest and 54th warmest October-March, regionwide, on record.

Much of the Primary Hard Red Winter Wheat Belt is located in the southern Plains, which is the epicenter of the Great Plains drought. The last three months ranked as the 45th driest January-March in the 1895-2023 record. However, the last 12 months ranked as the 11th driest 12-month April-March period, the last 24 months ranked as the 12th driest such 24-month April-March period, and the last 36 months ranked as the tenth driest such 36-month April-March period. For the 12-month time scale, April 2022-March 2023 was as dry as some of the corresponding 12-month time periods in the 1930s and 1950s droughts, but other years in those droughts were drier. For the 24-month and 36-month time periods, the 1950s drought was drier, but 2022-2023 was as dry as some of the corresponding time periods in the 1930s drought.

March also marks the beginning of the growing season for the Primary Corn and Soybean agricultural belt. March 2023 was mostly colder than normal, but wetter than normal in the southeast to drier than normal in the northwest. The month ranked as the 62nd coolest and 38th wettest March, regionwide, in the 1895-2023 record.

According to the U.S. Department of Agriculture (USDA), as of April 4, 2023, drought affected approximately 16% of barley production, 29% of corn production, 46% of cotton production, 4% of rice production, 90% of sorghum production, 20% of soybean production, 34% of spring wheat production, 48% of winter wheat production, 25% of hay acreage, 42% of the cattle inventory, 14% of the milk cow inventory, and 24% of the sheep inventory. Based on April 2 USDA statistics, 36% of the nation's winter wheat crop was in poor to very poor condition, and 24% of the nation's topsoil and 33% of the subsoil were short or very short of moisture (dry or very dry). The table below lists the soil moisture and winter wheat condition by state, with those states having 30 percent or more of topsoil or subsoil moisture short or very short, or 30 percent or more of the winter wheat in poor or very poor condition, highlighted in yellow:

Statewide topsoil moisture, subsoil moisture, and crop condition

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), March 2023 was drier than normal in parts of the FSM, and near to wetter than normal everywhere else.

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 Jaluit, Kwajalein, and Wotje (RMI); Saipan (Marianas); and Chuuk, Mwoakilloa, Ulithi, and Yap (FSM). March precipitation was above the monthly minimums at the rest of the stations across 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 tropical Pacific climatology can experience extremes in precipitation, from very low precipitation during the dry season to very high precipitation during the wet season. This can result in monthly normal precipitation values that are different from the monthly minimum needed to meet most water needs, and this can lead to percent of normal values that seem odd. This was the case during March 2023, which is in the wet season for American Samoa, Kapingamarangi, and Kosrae and dry season for most of Micronesia. Precipitation was below the monthly minimum but above normal (1981-2010 normal), because the normals are low, at:

  • Saipan: March 2023 precipitation 2.61 inches, March normal mean 1.93 inches, March normal median 1.89 inches.
  • Kwajalein: March 2023 precipitation 4.43 inches, March normal mean 3.56 inches, March normal median 2.35 inches.
  • Ulithi: March 2023 precipitation 6.38 inches, March normal mean 4.65 inches.
  • Yap: March 2023 precipitation 6.26 inches, March normal mean 5.34 inches, March normal median 4.56 inches.

Precipitation was above the monthly minimum but below normal (1981-2010 normal), because the normals are high, at:

  • Kosrae: March 2023 precipitation 10.81 inches, March normal mean 15.78 inches, March normal median 16.06 inches.

In the table below, the station identified as Koror is Palau International Airport (Airai).

Pacific Island Percent of 1981-2010 Normal Median Precipitation
Station Name Apr
2022
May
2022
Jun
2022
Jul
2022
Aug
2022
Sep
2022
Oct
2022
Nov
2022
Dec
2022
Jan
2023
Feb
2023
Mar
2023
Apr-
Mar
Chuuk138%176%68%107%70%121%124%93%116%92%215%85%110%
Guam NAS187%69%79%135%62%109%150%77%182%350%188%263%107%
Kapingamarangi66%10%25%61%51%44%34%55%53%166%47%116%53%
Koror303%203%81%72%119%45%241%88%105%187%102%185%122%
Kosrae195%132%139%169%117%134%169%107%99%131%188%67%115%
Kwajalein156%196%141%94%132%68%161%81%88%224%50%189%118%
Lukonor125%88%62%66%32%36%95%94%54%124%68%96%67%
Majuro255%66%71%96%74%159%147%91%90%157%138%169%119%
Pago Pago58%96%110%166%121%60%149%118%71%114%110%106%91%
Pohnpei157%112%122%173%138%143%148%85%74%136%146%109%124%
Saipan204%76%106%159%80%67%151%60%130%441%118%138%119%
Yap254%153%83%110%65%57%217%68%131%133%118%137%112%
Pacific Island Precipitation (Inches)
Station Name Apr
2022
May
2022
Jun
2022
Jul
2022
Aug
2022
Sep
2022
Oct
2022
Nov
2022
Dec
2022
Jan
2023
Feb
2023
Mar
2023
Apr-
Mar
Chuuk17.19"19.87"7.93"12.86"8.98"14.15"14.27"9.83"13.00"9.34"15.60"7.09"150.11"
Guam NAS4.74"2.35"4.88"13.71"9.15"13.74"17.12"5.66"9.32"14.02"5.69"5.45"105.83"
Kapingamarangi8.97"1.19"3.40"8.60"4.17"4.38"2.76"5.11"5.23"15.23"4.37"13.24"76.65"
Koror22.21"24.06"14.19"13.31"16.00"5.26"28.49"10.00"11.76"19.04"8.74"13.74"186.8"
Kosrae34.09"23.42"20.39"25.14"16.69"19.11"18.53"14.74"15.95"21.87"24.25"10.81"244.99"
Kwajalein8.21"13.17"9.78"9.23"12.81"7.34"18.02"9.09"5.88"7.08"1.32"4.43"106.36"
Lukonor14.14"10.27"7.19"10.52"4.55"3.70"10.73"8.52"6.06"10.45"6.08"8.92"101.13"
Majuro24.02"6.72"7.78"10.70"8.65"17.72"18.76"12.21"10.30"12.14"9.51"11.12"149.63"
Pago Pago5.42"9.32"5.84"9.23"6.53"3.92"13.82"11.93"9.10"15.19"13.19"11.34"114.83"
Pohnpei28.86"22.32"18.02"26.66"19.69"17.91"22.62"12.66"11.86"17.94"13.99"14.29"226.82"
Saipan5.36"1.81"3.84"14.16"10.55"6.72"16.07"3.39"5.01"11.16"3.05"2.61"83.73"
Yap14.28"12.04"10.04"16.54"9.57"7.76"26.48"5.99"11.17"8.51"6.11"6.26"134.75"
Pacific Island 1981-2010 Normal Median Precipitation (Inches)
Station Name Apr
2022
May
2022
Jun
2022
Jul
2022
Aug
2022
Sep
2022
Oct
2022
Nov
2022
Dec
2022
Jan
2023
Feb
2023
Mar
2023
Apr-
Mar
Chuuk12.47"11.30"11.66"11.98"12.86"11.71"11.51"10.61"11.25"10.10"7.25"8.32"136.77"
Guam NAS2.53"3.40"6.18"10.14"14.74"12.66"11.44"7.38"5.11"4.01"3.03"2.07"99.09"
Kapingamarangi13.64"12.08"13.78"14.15"8.13"9.93"8.19"9.27"9.84"9.15"9.27"11.43"145.85"
Koror7.32"11.83"17.48"18.53"13.50"11.77"11.84"11.39"11.16"10.18"8.56"7.44"152.90"
Kosrae17.51"17.75"14.64"14.91"14.22"14.22"10.94"13.83"16.11"16.67"12.93"16.06"213.87"
Kwajalein5.26"6.72"6.93"9.87"9.74"10.74"11.18"11.28"6.66"3.16"2.64"2.35"90.41"
Lukonor11.31"11.69"11.65"15.93"14.04"10.15"11.32"9.08"11.27"8.41"8.93"9.26"151.36"
Majuro9.42"10.11"11.01"11.17"11.69"11.17"12.73"13.44"11.39"7.74"6.88"6.58"125.25"
Pago Pago9.39"9.66"5.33"5.55"5.38"6.53"9.26"10.14"12.84"13.34"12.00"10.68"125.57"
Pohnpei18.41"19.96"14.81"15.43"14.26"12.55"15.27"14.83"16.08"13.18"9.55"13.17"182.36"
Saipan2.63"2.38"3.62"8.91"13.13"10.09"10.62"5.61"3.85"2.53"2.59"1.89"70.25"
Yap5.63"7.85"12.04"15.08"14.82"13.50"12.18"8.83"8.51"6.39"5.19"4.56"120.31"

As measured by percent of normal precipitation, Lukunor was drier than normal in the short term (March and the last 3 months [January-March]) and long term (last 12 months [April 2022-March 2023]). Kapingamarangi was drier than normal at the 3- and 12-month time scales, but wetter than normal for March. Chuuk and Kosrae (based on preliminary data) were drier than normal for March but wetter than normal at the 3- and 12-month time scales. Pago Pago was drier than normal in the long-term, but wetter than normal in the short-term. Airai, Guam, Kwajalein, Majuro, Pohnpei, Saipan, and Yap were near to wetter than normal for all 3 time periods.

Based on percent of normal average (instead of normal median values), in the Marianas Islands, precipitation during March and the last 2 to 24 months was generally above normal across the main islands. Longer time periods had a mixed anomaly pattern (percent of normal precipitation maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months).

Based on percent of normal average (instead of normal median values), in the Marshall Islands, the last 1 to 3 months and last 48 months were drier than normal in the northern and southwestern islands, the last 4 months were drier than normal in the western islands, wetter-than-normal conditions dominated most islands at the 6- to 36-month and 60-month time scales (percent of normal precipitation maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months).

According to the March 31 USDM produced for the USAPI, severe drought developed at Wotje, moderate drought continued at Kwajalein, abnormal dryness continued at Kapingamarangi and developed at Jaluit, and abnormal dryness ended at Lukunor and Pingelap, while the rest of the USAPI stations were free of drought and abnormal dryness.

The National Weather Service (NWS) office in Guam issued one Drought Information Statement (DGT) for drought in early April (on April 11) that noted several islands in northern RMI (north of 9 degrees N latitude) have requested drought assistance in the last few weeks. This includes, but is not limited to, Ebadon, Mejit, Wotje, Wotho, Maloelap, Likiep, Enewetak and Kwajalein. Low water catchment levels, browning of vegetation, and brackish well water have all been reported. The reservoir level on Majuro increased early in the month then generally held steady for the rest of the month. The reservoir level peaked at about 27.5 million gallons of water on March 19, had a minimum value of 22.3 million gallons on March 7, and ended the month at 25.7 million gallons. This is below the threshold of concern for drought of 28.8 million gallons. Some of the low water level is due to one sector of the reservoir being serviced. This portion of the reservoir system typically holds 8 million gallons, so the 22.3 million gallon minimum level was above the revised 20.8 million gallon level of concern.

Satellite observations of vegetation health (VHI, stressed vegetation, drought stress) on Guam generally indicated no drought concerns.

March 2023 precipitation ranks were mostly on the median to wet side of the historical distribution, based on data available at the time of this report. Record to near-record dryness was still occurring at Kapingamarangi and Lukunor at longer time scales:

  • Kapingamarangi: 16th driest (18th wettest) March (in a 33-year record), but 2nd driest rank for May-March and April-March.
  • Lukunor: 17th driest March (39 years), and driest July-March through April-March.
  • Jaluit: 7th driest June-March through April-March (37 years).

At the wet end of the scale, Mili had the wettest rank for January-March through April-March.

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 March 2023, October 2022-March 2023 (last 6 months), and April 2022-March 2023 (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.

March 2023 USAPI Precipitation Ranks (1 = driest)
StationMarch 2023Oct 2022-Mar 2023Apr 2022-Mar 2023Period of Record
RankYearsRankYearsRankYears
Ailinglaplap3540273835371981-2023
Airai6472697268701951-2023
Chuuk2272497247711951-2023
Fananu--8--6--22003-2023
Guam6067626643661957-2023
Jaluit124014387371981-2023
Kapingamarangi16335252181962-2023
Kosrae1153234031351954-2023
Kwajalein4771517149701952-2023
Lukunor17398371261981-2023
Majuro4769526954681954-2023
Mili2940363634341981-2023
Nukuoro740283834371981-2023
Pago Pago3657285720571966-2023
Pingelap1739--35--331981-2023
Pohnpei3672487269711951-2023
Saipan3542323429341981-2023
Ulithi3240313729361981-2023
Utirik--17--8--41985-2020
Woleai2441333527271968-2023
Wotje1140193727361981-2023
Yap4172587252711951-2023
Map of USAPIMarch 2023 Precipitation (Inches)
Map of USAPI March 2023 Percent of Normal Precipitation
Map of USAPI January-March 2023 Percent of Normal Precipitation
Map of USAPI April 2022-March 2023 Percent of Normal Precipitation

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

SPI values for seven time periods for Pacific Islands

NOAA Regional Climate Centers

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

Southeast

As noted by the Southeast Regional Climate Center, for the third straight month, mean temperatures were above average across the Southeast and March precipitation was below average across most of the region. For the fourth consecutive month, mean temperatures were near average across Puerto Rico and the U.S. Virgin Islands.

Monthly precipitation totals were less than 50 percent of normal across much of Virginia, coastal South Carolina, and pockets of southern Alabama and Georgia. The driest locations were found across the Florida Peninsula (except around Miami) and parts of Puerto Rico and the U.S. Virgin Islands, where monthly precipitation totals were less than 25 percent of normal. Sarasota, FL recorded its third driest March on record (since 1911) with just 0.18 inch (4.6 mm) of precipitation, while West Palm Beach, FL (1888-2023) and Henry Rohlsen Airport (1943-2023) on the island of Saint Croix tied their third driest March on record with just 0.12 inch (3.0 mm) and 0.29 inch (7.4 mm) of precipitation, respectively. Several other locations in South Florida recorded less than half an inch (12.7 mm) of precipitation for the month, including Orlando, Tampa, Fort Myers, Naples, and Key West. The persistence of dry weather in Florida has been noteworthy in places. Through the first three months of the year, West Palm Beach, FL has recorded just 1.47 inches (37.3 mm) of precipitation, the lowest amount on record (since 1888). Key West, FL (1871-2023) recorded its second driest start to the year with just 0.34 inch (8.6 mm) over the past three months, while Orlando, FL (1892-2023) recorded its third driest start to the year with 1.89 inches (48.0 mm) of precipitation.

The continuation of warm and dry weather led to a worsening of drought conditions across much of the Florida Peninsula, except in the extreme southeastern corner around Miami. Severe (D2) drought emerged across the southwestern part of the state and covered much of the Peninsula by the end of the month. A small pocket of extreme (D3) drought also emerged in parts of Collier, Hendry, and Lee counties. Abnormally dry (D0) conditions expanded across eastern portions of the Carolinas and much of Virginia, along with some pockets of moderate (D1) drought. Short-term drought conditions also worsened across the Caribbean. In Puerto Rico, moderate (D1) drought emerged across the south coastal and northwest regions, while abnormally dry (D0) conditions expanded across the eastern interior, southern slopes, and outlying islands. Abnormally dry (D0) conditions emerged on Saint John, while severe (D2) drought was introduced on Saint Croix. Moderate (D1) drought persisted on Saint Thomas. In contrast, parts of southern Alabama and Georgia, and the eastern Florida Panhandle, saw some improvements in abnormally dry (D0) and moderate (D1) drought conditions due to locally heavier precipitation amounts. Overall, about 30 percent of the region was in abnormally dry (D0) conditions by the end of the month, while moderate (D1) to extreme (D3) drought covered about 16 percent of the region. Across the Florida Peninsula, the warm temperatures and lack of precipitation continued to place stress on crops and vegetation. The biggest impacts were seen in pastures, which were in mostly poor to fair condition.

South

As explained by the Southern Regional Climate Center, March 2023 was warmer than normal across the southern portion of the region and near to cooler than normal across the north. Precipitation was above normal across much of Arkansas, eastern Oklahoma, northern Mississippi, far western Tennessee, northeastern Texas, and the Big Bend area of Texas. The remainder of the region generally recorded below-normal precipitation, with stations in the Panhandles of Texas and Oklahoma reporting less than five percent of average precipitation during March. The driest stations in the region reported no accumulated precipitation in March; they were all in Texas and were located: near Fort Hancock, Seminole, Gail, Plains, near Tornillo, Higgins, Lipscomb, near Odessa, and near Andrews.

During March, drought conditions largely remained the same across the Southern region, with 42.06 percent of the region experiencing some level of drought as of March 28th, compared with 40.88 percent on March 7th. Arkansas, Mississippi, and Tennessee remained drought-free during March. Moderate drought remains present in south eastern Louisiana. Much of central and western Oklahoma, the Texas Panhandle, central and deep southern Texas saw degradation of existing drought conditions during March, with Oklahoma seeing the percentage of Exceptional Drought increasing to 12.83% of the state by March 28th. Flooding was not common across the Southern Region in March 2023, though reported heavy rains in Sevier and Blount counties in Tennessee caused road closures on March 2nd. Water levels and flows along much of the lower Mississippi River remained well below historical means, with the exceptions being Memphis, Tennessee and Greenville, Mississippi where above average heights were observed.

Midwest

As described by the Midwest Regional Climate Center, the average March temperature for the Midwest was 34.4 degrees F (1.3 degrees C), which was 2.5 degrees F (1.4 degrees C) below the 1991-2020 normal, and March precipitation totaled 3.45 inches (88 mm) for the Midwest, which was 0.88 inch (22 mm) above normal, or 134 percent of normal. By month's end, the USDM indicated that 84 percent of the region had no dryness or drought. Drought that had been affecting southeast Michigan was nearly gone, and conditions in western Minnesota showed improvement. Iowa continued to be the primary drought-affected area, with about one-third in drought and one-third abnormally dry. Only a very isolated area of southwest Missouri had drought conditions worsen during March.

Northeast

As summarized by the Northeast Regional Climate Center, March temperatures were near to above normal and precipitation was below to near normal, along with two notable snowstorms and the introduction of moderate drought. The USDM from March 7 showed 2 percent of the Northeast as abnormally dry. These areas included small parts southern Maryland, southern Pennsylvania, southern New Jersey, and New York's Long Island. By month's end, increasing precipitation deficits, below-normal streamflow, and declining soil moisture led to the introduction of moderate drought in southern/eastern Maryland and the introduction/expansion of abnormal dryness in Maryland, Delaware, southern New Jersey, and southeastern Pennsylvania. The USDM from March 28 showed 1 percent of the Northeast in moderate drought and 6 percent as abnormally dry.

High Plains

As summarized by the High Plains Regional Climate Center, temperatures this past month were, for the most part, near to below normal for the region and precipitation was once again spotty. While snow continued to impact the northern states in March, precipitation was notably absent for much of the High Plains. Cooler temperatures helped with drought conditions; however, many places desperately need moisture this spring.

Much of Kansas and Nebraska were bone dry. Southwestern Kansas has been on the short end of the stick when it comes to precipitation for the past year, and March was no exception. Many places received less than 0.10 inch (2.54 mm) of precipitation, including Hays, Garden City, and Great Bend. Since the start of 2023, numerous locations have received less than 0.50 inch (12.7 mm) of precipitation. After record to near-record dryness last year, the situation continues to become dire and dire each month.

Drought conditions improved this month, primarily in North Dakota. Conditions did degrade in the southern portions of the region after minimal precipitation occurred. Overall, there was a 3 percent decrease in D0 to D4 (abnormally dry to exceptional drought conditions). After a bitterly cold and wet month, North Dakota experienced a 30 percent reduction in D1-D4 (moderate to exceptional). Despite the reduction in drought conditions, there was a minimal reduction in abnormally dry conditions with 95 percent of the state still observing D0-D4. While drought still remains entrenched in Nebraska, D3 to D4 (extreme to exceptional) was reduced by eight percent. Elsewhere in the region, other improvements and degradation were observed.

As the significant drought affecting Kansas enters the second year, a number of impacts are becoming apparent. Winter wheat is in incredibly poor shape, with some places not having meaningful precipitation in nearly 200 days. Fields are already being evaluated by insurance adjusters and being adjusted out, despite no wheat emerging. Farmers will be forced to find ways to hold soil in place in the coming months, as blowing dust has been an issue over the past year. The groundwater has been depleted, with water levels dropping nearly three feet near Garden City. A very unusual impact comes from the Kansas Department of Wildlife and Parks. Game Wardens within the state are seeing increased numbers of coyotes in towns this year due to the extreme drought conditions. The dry conditions have caused them to become desperate for sources of food and water.

West

As summarized by the Western Regional Climate Center, a strong and cold area of low pressure persisted for nearly the entire month in the West. This brought stormy weather for most of the West with several impactful atmospheric rivers making landfall along the coast. Most of the region saw well above-normal precipitation and below-normal temperatures. Mountain snowpack reached record high values throughout California, the Great Basin, and Colorado River Basin, and drought conditions continued to improve.

Below-normal temperatures were widespread across nearly the entire region except for a small area in southeast New Mexico. Precipitation was well above normal for most of the West except for the northern tier of the Pacific Northwest and southeast New Mexico. In California, Nevada, Utah, Oregon, western Colorado, and Arizona snowpack was well above normal at the end of March with most NRCS SNOTEL sites greater than 150 percent of normal snow water equivalent (SWE) and record high SWE values in many locations. In the central and southern Sierra Nevada, the long-term snow survey data from April 1 indicated that the 2023 snowpack was the deepest in the past 90 years, greater than previous benchmark years of 1952, 1969, 1983, and 2017 — and in some cases by a large margin. The Mammoth Pass, California, April 1 snow survey recorded 104.5 inches of SWE, which shattered the previous record of 86.5 inches from 1969.

According to the USDM at the end of March, 36 percent of the West was in drought with just one percent of the West in extreme (D3) or exceptional (D4) drought. The biggest drought improvements were found in California, the Great Basin, and north-central Montana. Only a few small areas of worsening drought were found in Oregon, Washington, northern Idaho, and western Montana.

In Alaska, temperatures were 2-4 degrees Fahrenheit below normal in the Panhandle while temperatures were well above normal across the North Slope. Precipitation was well above normal in western Alaska and below normal in South-central and the North Slope. Nome received 2.62 inches of precipitation (354 percent of normal) for the month ranking as the third wettest since 1907. Anchorage saw just 0.14 inch (20 percent of normal) for the month coming in as the seventh driest on record.

Precipitation was below normal for most of the Hawaiian Islands. Hilo received 7.4 inches for the month (58 percent of normal) and Hana logged 5.05 inches (60 percent of normal). South-central Hawaii (the Big Island) was one area where precipitation was above normal. The islands of Honolulu and Kauai saw warm temperatures 2-3 degrees Fahrenheit above normal. The monthly mean temperature in Honolulu was 76.9 degrees Fahrenheit (2.2 degrees Fahrenheit above normal) ranking as the second warmest since records started in 1941. Despite mostly dry conditions across the state there were no areas in drought status at the end of March according to the March 28 USDM.

Additional Resources


Citing This Report

NOAA National Centers for Environmental Information, Monthly Drought Report for March 2023, published online April 2023, retrieved on March 4, 2024 from https://www.ncei.noaa.gov/access/monitoring/monthly-report/drought/202303.