It’s often said in areas of drought in the southern U.S. that it takes a tropical storm to reverse the situation. This year, as we know, the Texas-Oklahoma drought was fairly well broken by a lingering storm system over Memorial Day weekend which resulted in more than 30 deaths.
Now comes what is left of Tropical Storm Bill, already as of this morning, reduced to a tropical depression. Some parts of Texas into Arkansas may see 2 to 5-inches of rain in the next day. While these rain totals don’t match some from the Memorial Day storms, they are excessive and flash flooding is a possibility.
As the remnants of Bill move slowly to the northeast across the next several days the heaviest rain will eventually spread into southern Illinois and on to Indiana by late Friday night into Saturday. Here’s the latest hydrological forecast discussion.
In fact, the remnants of Bill will interact with a stalled frontal system which has caused periodic heavy rain for more than a week as it waffled up and down across Illinois and nearby states. Flood warnings have been issued for several rivers in Illinois and extend into portions of the Mississippi River bordering the state. Flooding in Illinois ranges from major to minor and areas of heaviest precipitation have varied daily.
On Monday, tornado warning sirens sounded in downtown Chicago, a relatively rare occurrence. A funnel cloud was observed east of Midway Airport and another near Millenium Park which is just east of Michigan Avenue in the heart of the city. No touchdowns were reported, but some photos taken at the time show an unmistakable wall cloud.
What caused the recent devastating and deadly flooding in Texas, Oklahoma and other states? One thought, advanced by Accuweather and others, is that the developing El Nino played a role. As we’ve written before, an El Nino is warmer than expected waters in the Pacific Ocean. El Nino events result in a split jet stream and it the southern stream likely contributed to the flooding in the South. Typically, heavier than normal rains occur in Spring, Autumn and Winter of El Nino years in a swath from California into the Mid-South.
Historically, even weak and/or developing El Ninos can cause the extreme precipitation witnessed in May. California largely missed out although the area around San Diego picked up record rainfall. In past El Nino events California received most of its precipitation during winter months. It remains to be seen if the current event will last that long.
In the meantime drought conditions have been greatly lessened in Texas, at least in the short term. Of course that came with a terrible price…dozens of deaths and hundreds of millions of dollars in damage. The toll continues to rise and many rivers remain in flood.
EDEN Flood Resources:
The Climate Prediction Center recently issued its 90-day outlook for temperature and precipitation for the U.S. It also updated the drought monitor tool.
In general the outlook calls for the next three months to feature above normal temperatures in the western third of the country and in the far southeastern states. Alaska and the Pacific Northwest will also be warmer than usual. Below normal temperatures are confined to much of Texas and areas of adjoining states. Most of the country will see an equal chance for above or below normal temperatures.
Much of the nation may experience above normal precipitation from the southeast through the gulf states to the western plains and Rockies along with a good portion of Alaska. The above normal rainfall may bring drought relief to Texas and the four corners area. The Great Lakes states will see below normal precipitation and the potential of a developing drought. Lake levels and fire danger may be impacted.
The drought monitor shows little change in the near term for the hardest hit areas of the west, parts of Texas, and parts of the Dakotas, Minnesota and Wisconsin. Over the 90 day period of the outlook, the drought may ease in Texas and areas northwest of there. However, drought conditions may expand in the Great Lakes. Unfortunately, little or no relief is seen for California. Just this week water use restrictions of from 8% to 36% were enacted for some municipalities.