Tools used in the U.S. Monthly Drought Outlook (MDO) included the updated Climate Prediction Center (CPC) temperature and precipitation outlooks for February 2019, various short- and medium-range forecasts and models such as the 7-day quantitative precipitation forecast (QPF) totals from the Weather Prediction Center (WPC), the 6-10 day and 8-14 day CPC extended-range forecasts (ERFs), the Weeks3-4 outlooks, tools from CPC, dynamical models on the monthly time scale, the 384-hour total precipitation forecasts from several runs of the GFS, February climatology relative to other times of the year, El Niño temperature and precipitation composites, predicted soil moisture anomalies from the GFS model, and initial conditions from the Jan. 29 US Drought Monitor.
In the West, a relatively wet and cold weather pattern the past 30-days brought a decent increase to the WYTD (since Oct. 1) basin average precipitation and Snow Water Content (SWC) in the Southwest, especially to California, Nevada, and the Four Corners region, where most basins were near or above normal as of Jan. 31. Basin averages also increased across middle sections of the West (from Oregon eastward to Wyoming), but most remained somewhat below normal. To the north (Washington eastward to Montana), no change or a slight decrease in basin average precipitation and SWC occurred as mostly subnormal precipitation fell. Overall, however, the WYTD basin average precipitation and SWC were generally in good shape, with the lowest average basin precipitation (70-75% of normal) located in central Idaho, and the lowest average basin SWC (about 50%) was found in western Oregon and southern New Mexico as of January 31. As a result, the USDM responded with widespread improvements during the past month in the desert Southwest, California, Great Basin, and Four Corners region, and in portions of the Northwest. Some slight deterioration was made in central Idaho, southern Wyoming, and northern Colorado where subnormal precipitation fell during the past 60-days.
Since February (and winter) is climatologically wet for the Far West, especially since precipitation begins to decrease during the spring while temperatures rise, this month can provide a lot toward how well the Water Year ends up. This is particularly true in California where coastal areas normally receive 17-26% of their annual precipitation. Forecast-wise, the 7-day QPF depicts a robust wet storm for the West, especially in California; the 6-10 day ERF favors below-normal precipitation and temperatures in the Far West but above-normal precipitation in the Rockies; the 8-14 day ERF keeps the cold air in place but enhances precipitation odds in the Southwest; and the updated February LLF tilts toward above-normal precipitation in the Southwest and central Rockies. All of these factors suggest continued improvement for California, the central Rockies, and the Four Corners region. In contrast, a cold but drier forecast at the medium and 1-month periods in the Northwest, plus lower WYTD basin average precipitation and SWC than basins to the south, point more toward persistence than improvement. Enough precipitation, however, should fall (as snow) during February that should limit drought development in the Northwest and northern Rockies.
West forecast confidence is moderate in the Northwest, moderate to high in California, desert Southwest, and Four Corners region.
The small area of long-term drought (D1) in central North Dakota should persist until the spring thaw to see if enough moisture from snow melt entered the soil, especially since February (winter) is a dry time of year. A blanket of 4-12 inches of snow covered the frozen soils of the Dakotas where the D0 and D1 areas were located. Colorado and Wyoming were discussed in the West region. An area to watch in the future was western Nebraska where 30- and 60-day precipitation was less than half of normal - but close to normal at 90-days. Since this is the dry time of year, however,deficits were small, and the forecasts all tilted wet at all time scales.
High Plains forecast confidence is moderate to high.
The South is nearly drought free, except for a few small D1 areas in extreme northern Texas Panhandle and extreme southern Texas. A dry climatology, long-term deficits, and short-term dryness (less than half of normal precipitation the past 60-days) favors drought persistence in northern Texas, although the ERFs favor above-medium precipitation (but dry QPF and 1-month LLF = EC). In contrast, a wetter pattern in southern Texas in the short- and medium-terms and last week of February (1-month precipitation LLF = EC), plus the D1 is short-term, tilts the odds toward improvement by the end of February. Elsewhere, with near to above-normal precipitation anticipated at most time scales and no D0 elsewhere, development is not expected in the South.
South forecast confidence is medium to high.
There is no drought (D1-D4) over the Midwestern at this time, except for a small area of D0 in northwestern Minnesota that is buried under snow and frozen in place. With most locations recording a wet 2018, much of the region blanketed by snow, well above-normal precipitation falling the past 30-days, and all forecasts (from 7-day QPF to 1-month LLF) favoring above-normal precipitation, no drought development is anticipated for the Midwest. The spring thaw will determine if enough snow or moisture was left to remove D0 in Minnesota.
Midwest forecast confidence is high.
Across the Southeast, only southeastern Florida was experiencing any degree of dryness or drought, and much of this was reduced (improved) when 3-5 inches of rain fell across most of this area during January 20-26. Although the El Niño development favors above-normal precipitation here, the short and medium-range forecasts hint at subnormal rainfall and above-normal temperatures, the monthly update had EC for precipitation and good odds for above normal temperatures, and February is climatologically dry, hence persistence for the remaining D1 area.
Southeast forecast confidence is low to moderate.
At present, there is no abnormal dryness and drought over the Northeast. With much of the Northeast blanketed in snow, the past 30-days of precipitation were much above normal, numerous stations observed one of the top five wettest years on record in 2018, the 7-day QPF, 6-10 and 8-14 day ERFs, and favorable chances for above normal February precipitation, drought development is not expected anywhere.
Northeast forecast confidence is high.
Moderate to severe drought continues along the southern Alaska Panhandle. As this is primarily a long-term hydrologic drought, and that the updated February precipitation outlook favors subnormal amounts, the drought should continue to the end of February despite slight odds for above normal precipitation the first third of February. In Hawaii, subnormal precipitation is typically expected during an El Niño, and with an El Niño Watch currently ongoing during their normal wet winter season, moisture conditions have recently declined, with drought on the leeward sides and D0 across the windwards. This drier pattern is expected to continue during February, so persistence and development is favored for the islands. In Puerto Rico, short-term dryness has developed, but signals from dynamical models were mixed, and that it is their normal dry season, thus persistence was drawn for the existing two small D1 areas.
Alaska and Hawaii forecast confidence is moderate to high; moderate for Puerto Rico.
Forecaster: David Miskus
Next Monthly Drought Outlook issued: February 28, 2019 at 3pm EST