Matt Makens

The coverage area of drought increased during the past week and as of this
update abnormally dry and drought conditions cover more than two-thirds of the
Lower 48.

> Several upper-level troughs and closed lows moved in the westerly jet stream
flow across the contiguous U.S. (CONUS) during this U.S. Drought Monitor (USDM)
week. They dragged surface fronts and low pressure systems along with them. The
weather systems moved across the West then generally followed two storm tracks
after crossing the Rockies – one track was along the Canadian border, while the
other track was along the Gulf Coast states. As a result, above-normal
precipitation fell across parts of the West, much of the Gulf Coast from eastern
Texas and Oklahoma to Georgia, parts of the Mid-Mississippi Valley, and parts of
the northern Great Lakes and Maine. Precipitation amounts were generally 0.5-2.0
inches in the West where precipitation fell, but exceeded 2 inches across a
large part of the Gulf Coast states. The rest of the CONUS had below-normal
precipitation for the week. A swath from New Mexico to Lower Michigan, and parts
of the northern Plains and Far West, had little to no precipitation. With
upper-level troughs and surface cold fronts dominating the circulation pattern,
weekly temperatures averaged below normal across most of the CONUS. Drought or
abnormal dryness contracted in parts of the southern Plains to Southeast, where
heavy rains fell, and in parts of the northern Plains and Northeast, where
overall conditions warranted improvement. But drought or abnormal dryness
expanded or intensified across parts of the West, Midwest, other parts of the
Plains, and the Carolinas, as well as much of Hawaii and Puerto Rico. In these
areas, precipitation deficits grew and soils continued to dry. These changing
conditions were reflected in several drought indices and indicators, including
the Standardized Precipitation Index (SPI), streamflow and groundwater levels,
soil moisture measurements on the ground and from satellite as well as soil
moisture models, vegetation-based indices such as VegDRI, and mountain snow
water content (SWE) in the West. - https://droughtmonitor.unl.edu/
The drought situation remains one of the most severe in the past 20 years, still
trailing the 2012/2013 event.

Let's review precipitation for the past _______
30 days:

60 days:

120 days:

Year:

With long-term dryness clearly comes soil moisture issues which are reflected in
this map showing the root zone soil moisture.

With that in mind, look at the lack of improvement in the 90-day forecast. The
Corn Belt, Midwest, and Southern Plains do 'okay' into summer:

Part of that will be coming through in the next couple of weeks. 

Total precipitation through mid-May includes some above average precipitation
(green areas) for parts of the southern plains stretching toward New England.
Dryness (brown areas) remains across the west and northern plains.

That's for incoming precipitation. As far as storage and streamflow potential
based on snowpack, the western US has some highlights in the northern Rockies
and Pacific Northwest, however much of the snowpack for the Rio Grande and
Colorado River systems is quite low.

The May drought outlook will be issued next week, but plan on it to show a
spreading drought into more of the plains and around parts of the Great Lakes. 

That is based on the outlook for May which remains drier than average in most
cases across the Lower 48.

The long term outlook for drought through late July is shown below.

We do have good news in that another active weather week is ahead and includes
heavy precipitation in parts of Colorado to the plains:

Another soaking rain on the way? Recent rains exceed 3″ in spots as we look
ahead to the weekend, next weekThis week’s rain was plentiful for much of
Northeast Colorado, with some
locations across the northeast plains picking up more than 3″ of rain Tuesday
and Tuesday night. Elsewhere across the state folks were not as fortunate. As
we
look at
precipitation totals over the last 3 days we see a bullsey…Brendan HebertonApr
29, 2021Weather5280
[https://www.weather5280.com/2021/04/29/another-soaking-rain-on-the-way-recent-rains-exceed-3-in-spots-as-we-look-ahead-to-weekend-next-week]

Drought update & the outlook: Thursday, April 29th, 2021