Weather Wednesday – Tropical Depression Bill and Flooding

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.

BILL_qpfNow 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 map 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.

http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfpfd

http://videowall.accuweather.com/detail/videos/trending-now/video/4299689121001/watch:-huge-wall-cloud-moves-over-chicago?autoStart=true

Weather Wednesday – El Nino and the Texas Floods

KHOU via USA Today
KHOU via USA Today

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.

EPA
EPA

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:

Agriculture

Flood insurance

Misc collected resources

eXtension Flood Page

Weather Wednesday — Hurricane Season Outlook

Tropical Storm Ana earlier this month aside, June 1st marks the beginning of the “official” Atlantic Hurricane season. So what can we expect this year? Exact predictions are always iffy, but noted expert Dr. William Gray and his colleague Philip Klotzbach, both of Colorado State University, predict 7 named storms, three hurricanes and one major hurricane. If true, this would be one of the quietest hurricane seasons in the last 60-years. The long term average is for 12 named storms, six hurricanes and two major hurricanes. Some recent years have seen in excess of 20 named storms.

anomnight.current.small
NOAA

Why the smaller numbers? One factor is the development of a strong El Nino in the equatorial Pacific Ocean. Historically, El Nino years have fewer hurricanes along with other effects. The Weather Channel has created a nice page and video explaining this.

It is extremely important to note, however, that it only takes one major landfalling hurricane to cause vast damage and many casualties. Just because the long range hurricane forecast seems to be encouraging, we’re not out of the woods.

Hurricane-Sandy-stormsurgediagramIn preparation for the 2015 hurricane season, the National Hurricane Center is unveiling a new system of communicating storm surge threats and vulnerabilities. As has been seen over and over, some of the most devastating damage from hurricanes is not always from strong winds but from storm surge, the wall of water that is pushed out in advance of the center of the hurricane.

20121106-hurricane-sandy-new-jersey-shore.jpg.662x0_q100_crop-scale Hurricane Sandy is one of the more recent demonstrations of this mighty force.

This week, May 24-30, is national Hurricane Preparedness Week.  For those of you who have a role educating others about hurricanes here’s a link to FEMA’s toolkit.   And here is material from the National Hurricane Center/NOAA.

 

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National Dam Safety Awareness Day is May 31st. That date is the anniversary of the failure of the South Fork Dam which resulted in the infamous Johnstown (PA) flood. More than 2,200 lives were lost in what is considered the worst dam failure in the history of the United States according to FEMA.

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Missouri Institute of Science and Technology

The National Dam Safety Program is led by FEMA and a partnership of states, federal agencies and other stakeholders. Dams are part of an aging infrastructure and continued attention is vital in averting future catastrophic failures.