The moderate La Niña event is expected to slowly relax over the next few months, and thus its influence on the Nation’s weather should gradually decline. But for March 2021, it does not look like any decline in strength will be sufficient to reduce its influence, so it remains a significant factor in the Climate Prediction Center’s (CPC’s) outlooks.
Subnormal March Precipitation is favored in the eastern Great Basin, the Four Corners States, much of the central and southern Plains, the immediate Gulf Coast, and Florida. This includes much of the region currently experiencing entrenched severe to exceptional drought (D2 to D4 on the Drought Monitor).
Meanwhile, the odds tilt toward surplus precipitation in the Great Lakes Region, the Ohio and Tennessee Valleys, the middle Mississippi Valley, central and eastern Alaska, and Hawaii. Much smaller patches of less-severe drought are scattered across these regions.
Below-normal temperatures are anticipated in the Far West and the southern one-third of Alaska, but warmer than normal conditions are favored over a much larger part of the country, specifically from the eastern Rockies to the Atlantic Coast, in northern Alaska, and throughout Hawaii.
February 2021 brought a variety of changes to the areas in drought, but the bottom line is that much of the western half of the Nation remains in some degree of dryness, and extreme to exceptional drought (D3 and D4) continues to cover most of the Four Corners States and the southern Great Basin, plus some adjacent areas.
Drought conditions improved along the West Coast and in most of Hawaii, and scattered patches of improvement were observed in part of the Four Corners States, the adjacent northern Rockies, the central Plains, central and western Texas, and widely scattered locales farther east. At the same time, dry conditions worsened in some parts of the Intermountain West, northern Montana, the northern Plains, the remainder of Texas, and again in scattered patches farther east.
Taking all this into account, the Drought Outlook through March 2021 expects conditions to generally persist in areas currently affected by drought, with development expected in parts of the central and southern Plains and much of the Florida Peninsula. Improvement or removal is only forecast for southwestern Oregon and immediately adjacent areas, and across Hawaii.
Forecast confidence is low to moderate for the Southeast.
- Most of the Southeast Region is drought-free, save for a small part of central Alabama.
- The forecast here is tricky, with drier than normal conditions favored later in March, but about 2 inches of rain is expected during the first week, which should be sufficient to remove drought.
- Farther south, recent moderate rainfall in parts of northern and eastern Florida has delated the introduction of drought in the state, and additional light to moderate rains may continue into early March in some areas. As a result, drought is now not expected to develop across northern Florida and parts of east-central Florda by the end of the month.
- Farther south, where short-term rainfall has been less generous & the CPC outlook for March as a whole favors deficient precipitation and above-normal temperatures, it seems likely that drought will be affecting at least part of that region by the end of the month.
Forecast confidence is moderate to high for the South.
- In the South Region, the most intense drought (D3) covers parts of northwestern Texas, the Big Bend, and Deep South Texas. Moderate to severe drought covers much of central, western, and northeastern Texas, plus smaller areas across western Oklahoma and isolated spots in Tennessee, Mississippi, and Louisiana.
- The outlook in this region is mixed, with most of the small drought areas from Louisiana eastward expected to improve due to enhanced chances for surplus rainfall in the short-term and/or for the month as a whole.
- In contrast, moderate drought along part of the Louisiana coast is expected to continue due to lesser precipitation in the short-term, and odds favoring deficient rainfall and above-normal temperatures for March as a whole.
- Farther west, abnormal precipitation is favored on time scales covering the last half of March, plus the month as a whole. Given this and the expected above-normal temperatures, drought is forecast to expand eastward, filling in parts of central and southeastern Texas currently outside the drought areas.
- The forecast development may have been more aggressive farther north and east but for significant rainfall in the short-term, which should keep drought at bay there for a few weeks.
Forecast confidence is high for the Midwest.
- Currently, very little drought exists in the Midwest Region. Only a swath from northwestern Indiana into central Illinois, a couple areas in northern Minnesota, and most of western Iowa are experiencing moderate drought, though a degree of abnormal dryness covers larger areas, extending into southeastern Michigan and also stretched across roughly the northwestern half of the Midwest Region.
- For most of the Midwest, precipitation for the first 7 to 10 days should be light at best north of the Ohio Valley, but outlooks for later in the month generally favor surplus precipitation east of the Mississippi River, as does the forecast for March as a whole.
- This is consistent with conditions favored during La Niña episodes, and makes the forecast for removal obvious in central and eastern portions of the Midwest.
- Drought from Iowa northward through northwestern Minnesota is outside the area of expected March wetness, and March is typically one of the drier months of the year under the best of circumstances, bring on average less than 5 percent of the annual precipitation total. Thus relief is not expected there.
Forecast confidence is high for most of the High Plains, but moderate in the northern and eastern extremities.
- In sharp contrast to areas farther east, a large majority of the High Plains Region is covered by drought as March commences. Only southeastern Kansas, northwestern Wyoming, and portions of the eastern tier of the High Plains Region are not currently experiencing some degree of drought.
- Extreme to exceptional drought is entrenched across a large part of this region, including western Kansas and adjacent Nebraska, most of Colorado, and central Wyoming.
- Enhanced chances for above-normal March temperatures exist Region-wide, and odds favor subnormal precipitation in most of the region outside North Dakota and the extreme eastern tier.
- In these latter areas, little or no precipitation is anticipated through the first 1 to 2 weeks of March, but odds slightly favor above-normal precipitation around mid-month. But the expected warm weather and the fact that this is a drier time of year (March usually brings less than 5 percent of the annual precipitation total), persistence is most likely here too.
- Drought could expand into other parts of this Region, but the potentially wetter-than-normal mid-month reduces confidence enough that development in a given specific area can’t be anticipated with any confidence.
Forecast confidence is high for the Four Corners States and eastern Great Basin, and moderate elsewhere in the West.
- With warmer and drier than normal weather favored for March as a whole, the only reasonable forecast is for the long-term drought to persist in the Four Corners Region, the eastern Great Basin, and Wyoming.
- Persistence is also the only reasonable forecast for eastern Montana, where it should be warmer than normal and March is one of the drier times of the year.
- Farther north and west, the forecast is more difficult. The Far West is favored to be cooler than normal in March, with no tilt of the odds toward either precipitation extreme evident.
- It is also one of the wetter months of the year from Idaho and Utah westward. This is particularly the case in central and southwestern California, where March on average brings about 15 percent of the year’s precipitation.
- In the end, only southwestern Oregon and a small part of northern California are expected to experience substantial relief, with other areas remaining approximately unchanged. Those areas normally receive substantially more precipitation than points further south and east, where the entrenched, long-term nature of the drought should preclude substantial improvement brought by normal amounts of precipitation.
Forecast confidence is low for the Northeast.
- Drought gradually receded from the Northeast in late 2020 due to increased precipitation and minimal impacts, but small areas of moderate drought remain in much of Vermont and nearby locations in New Hampshire and New York.
- These areas reported 1 to locally 3 inches of precipitation during the past 30 days, which left snow depth at or slightly above normal outside northern Vermont.
- March is expected to bring light to moderate precipitation to these areas over the first few days, but odds slightly favor below normal precipitation during March 6-10. For the rest of the month, no tilt of the odds toward above nor below normal precipitation could be determined.
- With a generally decent snowpack, no indicators leaning away from climatology for the month as a whole, and no sign of increasing impacts (common in winter), a low-confidence forecast of improvement seemed the most prudent course.
Forecast confidence is high in Hawaii and Alaska, and low in Puerto Rico.
- In Hawaii, CPC’s outlook calls for enhanced chances for above-normal March precipitation, consistent with expected conditions during La Niña. This is also a wetter time of the year for the islands in any case, so further improvement or removal is expected through all areas of drought across the state.
- Puerto Rico is a more difficult forecast, but some monthly models point toward better-than-usual odds for an unusually dry March, and in the absence of other significant indicators, persistence is anticipated for the moderate drought on northern parts of the island.
- Although some abnormal dryness exists in parts of Alaska, there’s no indication that conditions will deteriorate enough to introduce drought anywhere in the state by the end of the month.