Dry enough for you?

Despite recent rain, parts of North Carolina could face a worsening drought if a dry pattern returns in the coming weeks.

Charles “Chip” Konrad, director of the Southeast Regional Climate Center based at Carolina, said that as of June 8 central North Carolina is classified as abnormally dry, the lowest of five drought levels. The state’s eastern and southeastern counties are mostly in the next category, moderate drought. And a small region is experiencing the third level of severe drought.

After one of the wettest winters ever recorded, meteorological spring — March 1 through May 30 — had record dryness. Only 5.02 inches of rain fell at the Raleigh-Durham International Airport, for example.

Chip Konrad

Konrad, a climatologist in the College of Arts & Sciences’ geography department, talked with The Well about the drought and its causes. He urges the general public, municipalities and industries to conserve water and plan for the possibility of increased drought.

What’s caused the drought in North Carolina?

In recent years, we’ve seen more of what we call hydroclimatic variability. That’s when there are more exceedingly wet days interspersed with longer periods of dryness. To put it another way, more floods, but also more droughts.

What we’ve seen over the last six months is consistent with long-term trends associated with climate change. This does not mean that the drought occurred because of climate change, but what we’ve experienced is something that the general circulation models see occurring more frequently in response to the increase in greenhouse gases.

If you watch the Weather Channel, they show the jet stream position to signify the tracks of low-pressure systems and their inclement weather. This “ridge” position across the Southeast has deflected a lot of rain-bearing storms and low-pressure systems to the north and west.

That’s a direct causal effect. Ridging is not something that we see every year. In fact, in 70-some-odd years of recordkeeping, this is the driest spring on record. Where we live, there’s a lot of natural variability in the atmosphere. Ridges are always found on the weather map, and between them are troughs or dips in the jet stream that bring low-pressure systems and precipitation southward. They’re in constant flux, but unfortunately this spring we were stuck in a pattern where the ridge remained positioned over us a lot more than normal.

What changes has this drought caused so far?

The impacts to this point are minimal. The only notable impact would be in agriculture for farmers who planted crops in the last month with hardly any rain. So, they’re not off to a good start. However, short-term droughts can sometimes be silver linings as they dry out the soil enough so farmers can plow and get their fields ready to plant. That silver living was present this year, as soils in many areas started off very wet. Fortunately, ground level water tables are in the normal range, which means that streams are still being fed by a decent amount of water, courtesy of the plentiful rain that fell prior to March. However, the flow in some creeks is getting low, except where lots of rain fell last week.

What’s the forecast for North Carolina?

If we don’t get much rain over the next two months, we’re going to be in bad shape come August and September. In a typical summer, the warmth and abundant sunlight reduces the amount of soil moisture, and the rain, which often falls at a high rate, largely runs off the surface instead of infiltrating into the ground. Given the current soil moisture deficit, the drought could potentially worsen or reemerge in areas that received the very heavy rain last week.

When summer drought emerges, some local areas get relief from the convective rainfall and nearby areas get worse. We call it “measles drought” because of the patchiness of dryness that results.

Temperatures have been a little above normal, but not too much, without too many hot days yet. That’s been a godsend in a way because the hotter it is, the more evaporation you get and the more stress that puts on the vegetation. Lawns are in OK shape now, but in my neighborhood, people are starting to water. It has taken a while for the soils to dry out due to recent cool conditions and deep soil moisture from the wet winter.

If this scenario unfolds, more people will water their lawns, which will put an even greater strain on the water supply.

I haven’t heard about any conservation measures yet, but it wouldn’t surprise me if they’re here real soon, if we dry out again. I’d encourage everyone to start conservation measures now on the chance that high heat and dryness return.