Montana Drought & Climate — March Update

A shower rolls through at The Pines Mesonet Station on the afternoon of March 22nd.

Here’s what you’ll find in this newsletter:

• MCO update
• Precipitation and Temperature update
• Snowpack, Soil Moisture, and Streamflow update
• Drought update

MCO Update

Mesonet Photo Explorer Now Live!

Screenshot of Mesonet Photo Explorer Map.

Dr. Kyle Bocinsky, Director of Montana Climate Office Extension, developed the Mesonet Photo Explorer. This interactive state map shows the entire library of images captured by the Montana Mesonet stations, searchable by cardinal direction and timestamp at 9 am & 3 pm. This is a great way to visualize what the weather is doing across the state at a glance!

Here is the MCO post sharing the new Photo Explorer.

In Brief

• Warm temperatures continue to reduce snowpack.
• The state has maintained a similar USDM status, with a slight degradation in the eastern part of the state.
• The western part of the state had above-average precipitation in the form of rain at lower elevations.

Month Report

Temperature

Montana Temperature Deviation

 Source: MCO Drought Dashboard D3.

The temperatures recorded in the Upper Missouri River Basin continue the trend for the second-warmest winter on record. This warm trend has been consistent for each month of the snowpack accumulation season, significantly reducing the snowpack at lower elevations and impacting soil moisture conditions.

The northwestern part of the state has seen a moderation of excessively warm temperatures due to repeated atmospheric river events, which have hindered temperatures from reaching as high as the southern part of the state.

Seasonal Temperature Outlook (AMJ)

Source: Climate Prediction Center.

The temperature predictions for April, May, and June show that Montana is leaning towards warmer temperatures for the entire state, with probabilities being higher in the southwestern corner, transitioning to lower probabilities in the northeast corner, at equal chances of near normal temperatures.

Monthly Temperature Outlook (April)

Source: Climate Prediction Center.

The monthly outlook for April is leaning above for warmer-than-normal temperatures with higher probabilities in the southwestern part of the state.

Precipitation

Source: MCO Drought Data Dashboard (D3).

The MCO’s D3 drought data dashboard precipitation percentiles over the last month show the western half and central part of the state have been significantly wetter than the last 30-year rolling baseline.

The precipitation trend has shifted this month for part of the state, with a major atmospheric river event bringing precipitation and snowpack levels back near normal ranges for this time of year. The large March snow event brought snow totals to 59 inches at Lolo Pass.

Seasonal Precipitation Outlook (AMJ)

Source: Climate Prediction Center.

The seasonal precipitation outlook for April, May, and June shows a 33–40% chance of below-normal precipitation across more than half of the state. With only a small part of the southwest corner of the state at a 40–50% chance of below normal precipitation.

Monthly Precipitation Outlook

Source: Climate Prediction Center.

The monthly precipitation outlook shows that the entire state of Montana is expected to have equal chances of normal precipitation in April.

Snowpack

Source: USDA Snow and Water Interactive Map

March had a significant snowstorm from the 11th to the 14th, which boosted SWE for most of the western basins in the state, followed by warm temperatures that began melting out some of the accumulated snowpack. The pattern of high-elevation SNOTEL sites maintaining at or above-average SWE, and low-elevation sites much below normal, has held over the month. The Bear Paws are experiencing the lowest snowpack on record, at 0–3%.

Typically, April 1st marks the date of maximum accumulated SWE in the state, but with the warm temperatures, accumulation is beginning to decline sooner.

Streamflow

This will be a critical time to monitor runoff across the state. The continued lack of snow at low to mid-elevations is limiting the potential for streamflow forecasts to exceed normal values. Continued above-normal temperatures in April could trigger an early runoff season. Stay-tuned for an in depth update about streamflow conditions across Montana in the next newsletter.

The MCO’s D3 Headwaters Hydrology Streamflow product is showing that the state is experiencing complex and varied streamflow conditions. The atmospheric river that dumped many inches of snow on the 11th–14th, in the NW, coupled with high temperatures that occurred afterward, is contributing to snowmelt events that are being picked up on USGS stream gauges. The image below of Spotted Bear River shows that spike of runoff.

Drought

March USDM Status

Source: USDM Montana Map: https://droughtmonitor.unl.edu/

Drought conditions have remained steady across the state this month, with a class degradation from north to south on the eastern edge of the state. Some improvements have been D2 status removal from parts of Fergus County and Judith Basin County. Parts of Ravalli, Granite, and Powell counties have also shown a class improvement.

USDM 4 Week Class Change

Source: Four week change map by UNL NDMC.

Seasonal Drought Outlook (AMJ)

View of Montana

Source: NOAA Drought Outlook Map.

The seasonal drought outlook for March through June shows that drought persists throughout the state, except for west of the continental divide. This persistence is due to low snowpack, record heat in mid to late March, which facilitated early and rapid snow melt, as well as an increased chance of below-normal precipitation and above-normal temperatures during April-May-June (AMJ).

Drought development is unlikely for the state, except for the patch of yellow indicating likely development in the area south of Dillon, which is due to the prediction of above-normal temperatures and below-normal precipitation for that area.

Soil Moisture

Source: Montana Climate Office Drought Dashboard

This SPoRT-LIS Soil Moisture anomaly map of Montana is showing that the southeastern corner of the state is experiencing low soil moisture conditions that coincide with the USDM drought class degradation. It will be important to monitor spring soil moisture conditions over the next few months.

ENSO

Source: the Climate Prediction Center/NCEP/NWS. Updated March 12th.

The CPC predicts a transition from La Niña to ENSO-neutral in the next month, with ENSO-neutral through May-July 2026 (55% chance). In June-August 2026, El Niño is likely to emerge (62% chance) and persist through at least the end of 2026.

Reference

Weather and Climate — The difference between weather and climate is timescale. Weather is the day-to-day interaction of factors like temperature, humidity, precipitation, cloudiness, visibility, and wind. To understand climate at a given place requires looking at weather trends over relatively long periods of time—months, years, and decades. In addition to studying weather, scientists examine climate trends or cycles of variability to understand the bigger picture of long-term changes.

Temperature and Precipitation — Throughout this newsletter, we report past temperature and precipitation data derived directly from the GridMET daily 4-km-gridded meteorological dataset from the University of Idaho. Temperature data are reported as seasonal averages; precipitation data are reported as seasonal total precipitation. Our three-month temperature and precipitation forecasts come from NOAA’s Climate Prediction Center.

style=”width:0.65in;height:0.65in” /> Climatologists use the term “normal” to compare current conditions or forecasts, such as temperature or precipitation, to the past. Here, the normal value is the statistical mean (the average) for a given measurement in a specific place during a specific period of time. Climatologists use the most recent 30-year period, rounded to the nearest decade, to define normal in North America: 1981–2010. The goal is to look far enough back in time to capture variation in weather patterns, but not so far as to be irrelevant to recent conditions. In 2026, we will start using the 1996–2026 period.

La Niña/El Niño — El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific, the El Niño Southern Oscillation (ENSO). When ENSO is between warm and cool phases, conditions are called ENSO Neutral. ENSO is one of several global climate phenomena that affect Montana’s weather patterns, and ENSO conditions often guide seasonal climate projections for Montana. Current ENSO conditions and up-to-date projections are available on NOAA’s ENSO website.

Snow Water Equivalent (SWE) — SWE is the amount of water contained within the snowpack. It can be thought of as the depth of water that would theoretically result if you melted the entire snowpack. SWE is measured across the West by the USDA Natural Resources Conservation Service’s SNOTEL network of snow monitoring stations. The SWE percent of normal represents the current snow water equivalent found at selected SNOTEL sites in the basin compared to the normal value for those sites from 1981–2010.

Root Zone Soil Wetness — Root Zone Soil Wetness is a measure of how much water has saturated the soil. More specifically, it’s the relative saturation between completely dry (indicated by a 0) and completely saturated (indicated by a 1) between 0 and 100 cm depth. In the maps in this newsletter, soil saturation comes from NASA’s Soil Moisture Active Passive (SMAP) satellite program “SPL4SMGP” data product. Soil moisture is mapped using a combination of radar and radiometer measurements from space and surface observations at an approximately 9-km spatial resolution.