Drought predicted to continue though April; record low Lake Michigan water levels

Rain and snow from the a series of winter storms that have swept across the nation so far in 2013 have put only a slight dent in the Great Drought of 2012 - 2013, and the drought is likely to extend at least until late April, according to the latest U.S. Drought Monitor report and NOAA Seasonal Drought Outlook, issued Thursday. The area of the contiguous U.S. covered by moderate or greater drought began 2013 at 61%, and is almost unchanged as of January 15, at 59%. According to NOAA's monthly State of the Drought report, the drought peaked during July 2012, when 61.8% of the contiguous U.S. was covered by moderate or greater drought. This made the 2012 drought the greatest U.S. drought since the Dust Bowl year of 1939, when 62.1% of the U.S. was in drought. The 2013 drought will maintain its grip over the U.S. into February, according to the latest 15-day precipitation forecast from the GFS model, which predicts a much below-average chance of precipitation across the large majority of the drought region during the next two weeks. These dry conditions will continue to cause problems for shipping on the Mississippi River, where barge traffic has been limited by near-record low water. However, the river level at St. Louis has risen about a foot since the beginning of the year, and the Army Corps of Engineers blasted away rock formations on the river bottom near Thebes, Illinois over the past two weeks, which should allow limited barge traffic to continue on the river at least through the end of January. The Corps now believes that will be able to keep shipping on the Mississippi River open into the summer. The latest NOAA river level forecast calls for the river to fall below -5' by January 30, which would be one of the five lowest water levels on record for St. Louis.


Figure 1. Predicted 7-day precipitation for the period ending on Friday, January 25. Less than 10% of the U.S. drought regions are predicted to receive as much as 0.5" of precipitation (dark green color.) Image credit: NOAA.


Figure 2. NOAA's January 17 Seasonal Drought Outlook calls for drought to persist over at least 70% of the U.S. drought area through the end of April. The drought is expected to ease some along its northern and eastern edges, but new areas of drought are predicted to develop over Texas, California, and the Southeast U.S.


Figure 3. The latest NOAA river level forecast calls for the Mississippi River to fall below -5' by January 30. The river's lowest level on record, -6.2', occurred in January 1940, after the great Dust Bowl droughts of the 1930s.

Lake Michigan and Lake Huron hit all-time record low water levels for January
Low water is also a problem on Lake Michigan and Lake Huron. After setting an all-time record low for the month of December, water levels have continued to fall, are are now 1" below the record-lowest January water level, observed in January 1965, according to the Army Corps of Engineers. Water levels on Lake Michigan, Lake Huron, and Lake Superior are predicted to fall 1 - 2" over the next month, due to below average precipitation. Lake Michigan and Lake Huron are already at 576.0', so if this forecast verifies, they will set the record for their all-time monthly level, the 576.05' level of March 1964. Lake Superior is still 6" above its all-time low water level, so will not set a new record. Below average ice cover, which allows increased evaporation, is contributing to the low water levels. The low ice cover is due to the record warm year of 2012, which has left the lakes 2 - 3°C above average in temperature, as of January 8. Barges on the lakes are being forced to carry reduced loads due to the low water. Great Lakes water level data goes back to 1918.


Figure 4. The water level on Lake Huron and Lake Michigan measured during 2012 - 2013 (red line) hit an all-time December monthly low during December 2012, beating the record set in 1964. The predicted water levels for January - March call for record lows all three months. Image credit: Army Corps of Engineers.

Long-term drought outlook
NOAA's January 17 Seasonal Drought Outlook calls for drought to persist over at least 70% of the U.S. drought area through the end of April. The drought is expected to ease some along its northern and eastern edges, but new areas of drought are predicted to develop over Texas, California, and the Southeast U.S. I don't see any signs of a shift in the fundamental large-scale atmospheric flow patterns coming, and it is good bet that drought will be a huge concern as we enter spring. NOAA's Climate Prediction Center predicts an increased chance of drier than average conditions over southwestern portions of the drought region during the coming three months. In general, droughts are more likely in the Midwest U.S. when warmer than average ocean temperatures prevail in the tropical Atlantic, with cooler than average ocean temperatures in the tropical Eastern Pacific (La Niña-like conditions.) This is what we had in during most of 2012, and continue to have in 2013. In fact, the equatorial tropical Pacific has cooled in recent weeks to 0.6°C below average (as of January 14). This is similar to the ocean temperatures seen in the spring of 2012, just before the Great Drought of 2012 began. Most of the U.S. drought region needs 3 - 9" of precipitation to pull out of drought.

Drought links:
My post on Lessons from 2012: Droughts, not Hurricanes, are the Greater Danger discussed how drought is our greatest threat from climate change.

Ricky Rood blogs about the Dust Bowl

Wunderground weather news
Wunderground's Angela Fritz has put together a weather news feature that provides a selection of recent media articles on major global weather events. For example, Sydney, Australia's biggest city, set it's all-time heat record today, with the temperature peaking at 45.8 degrees Celsius (114.4 Fahrenheit). The old record, of 45.3 C (113.5 Fahrenheit), was set in January 1939. Also, heavy snow hit Britain today, and a dock from Japan showed up on the coast of Washington.

Featured blogger Lee Grenci has a new post today on the incredibly intense 932 mb low that affected the Aleutian Islands yesterday.

Have a great weekend, everyone!

Jeff Masters