Matt Makens

The latest drought monitor released Thursday continues to show the primary
issues around the Four Corners region to Texas as well as the Pacific Northwest.

What that drought monitor does not show is the extreme evaporative losses during
the past two weeks across the Central Rockies, the Southwest, and Texas.

Losses like that will result in a rapid expansion of the drought and severity of
drought in these areas. However, later in this post we have a somewhat wetter
outlook that will help recover some of that water loss.

Let's check the recent conditions via The National Drought Mitigation Center,
University of Nebraska-Lincoln:

Summary

"High pressure dominated the southern half of the contiguous U.S. (CONUS) during
this U.S. Drought Monitor (USDM) week. Upper-level weather systems tracked
across the U.S.-Canadian border, dragging surface lows and fronts along with
them. The frontal systems tapped Gulf of Mexico moisture to drop locally heavy
rain across parts of the Plains to Midwest, while convective thunderstorms
peppered coastal areas of the Gulf. The high-pressure ridge inhibited
precipitation across much of the southern Plains to Southeast, and across most
of the West. It also kept temperatures unusually hot, with daily maximums
exceeding 90 degrees F across the South throughout the week and across much of
the West for most of the week. The excessive heat spread into the northern
Plains, Midwest, and into the Northeast as the week wore on. The persistent heat
increased evapotranspiration, which dried soils and stressed crops and other
vegetation. The locally heavy rains brought temporary relief from the heat and
dryness, but only for those areas in the Plains and Midwest lucky enough to
receive the rain."

Observations

Observations the past two weeks. Note, we are starting to see a wetter trend for
the northern and central plains as expected - we discussed this likelihood in
our July outlook. The rest of the country is has dismal precipitation. This is
the percent of normal precipitation:

And, the past 30 days:

The Outlook: Week 1

The precipitation outlook for the next week, running through July 30th is
favorable for, at least a brief, amount of tropical moisture spread from Mexico
into eastern Arizona and western New Mexico into southern Colorado. This
'monsoonal' type flow may not last into August, however.

The Outlook: Week 2

For week 2, let's see the general probability of drier versus wetter than
average areas from NOAA. Given the pattern, and absence of persistent storminess
over the drought regions, it is easy to see why the highest drought region will
remain drier than average. 

The above average areas of precipitation are more likely in parts of Texas, but
mostly over the deep south. As mentioned above, the tropical flow into the Four
Corner region for the next week, isn't likely to continue into August:

The Outlook: Month

For the next month, we see a trend toward much drier than average conditions for
brown shaded areas (extremely so in the reds), and wetter than average in the
green shaded regions. The favored precipitation areas will be the northern high
plains.

The monsoon's forecast isn't all that exciting and not at all like a classic
setup where Arizona catches up on rainfall. This year will be a marginal
monsoonal flow that favors areas far east of where we classically look for the
tropical flow. 

So, the long-term forecast that goes into late August will also likely remain
drier than average for the Southwest, but parts of Texas, New Mexico, and
Southeastern Colorado may see some amount of drought relief.

Drought update & the outlook: Thursday, July 23rd, 2020