RodneyNeff's Blog

Below is a graphical representation of the the % above/below mean precipitation for April 1 to June 10th and March 1 to June 10th of 1993 and 2008.

Since 1896, precipitation during this period has averaged 18.72 inches, said Pat Guinan. The previous record was the six months ending in May 1973, which saw 29.21 inches of precipitation.

Prodigious rainfall has saturated soil, putting Missouri corn farmers weeks behind schedule in planting, forcing many to consider switching to soybeans or other crops.

The state has also endured more than its usual share of tornadoes. Since Jan. 1, nearly 60 tornadoes have hit Missouri, almost twice the number the state sees in a typical year. On May 10, a devastating twister killed 15 people in Newton and Barry counties, making it the deadliest single tornado to strike Missouri in almost 50 years.

The culprits behind the state’s wet and windy weather include above-normal temperatures in the southern United States and below-normal temperatures in the north. “The larger contrast in air masses provides more opportunity for unstable weather,” Guinan said.

Running between these air masses is the jet stream. During most winters, this high-altitude air current travels across the southern U.S. “This year that has not been the case,” he said. “It’s been a few hundred miles to the north, pretty much running from the central Rockies to the Great Lakes area. That puts Missouri in the storm track.”

The jet stream changed its itinerary thanks to the La Niña phenomenon, a recurrent cooling of surface waters in the equatorial Pacific. (There is also a corresponding interval of higher-than-normal water temperatures, which climatologists call El Niño.)

La Niña has been losing strength since February. Does that mean calmer, sunnier days lie ahead? Climate scientists are confident that the answer is “maybe”: The National Weather Service’s Climate Prediction Center forecasts equal chances of high, low and normal amounts of rainfall in Missouri this summer.

To add insult to injury, below-normal spring temperatures abruptly gave way to above-normal temperatures in many parts of Missouri at the end of May. High humidity has made the warm weather especially oppressive.

“It seems like an early start to summer with the hot and sticky weather that we’re already feeling across a good part of the state,” Guinan said.

The good news, he said, is that the Climate Prediction Center anticipates below-normal temperatures on average from June through August.

The National Weather Service in St. Louis (WFO LSX) will soon be receiving super resolution (super-res) radar data. The scheduled installation of this new software, weather permitting, is Tuesday, May 27th. 

Super resolution radar data will improve NWS warning operations by giving forecasters a more detailed picture of thunderstorm structure and its severe potential.  For more information on super-res radar data click here.

Initially, the data will not be available on any NWS website. However, some third party vendors will be distributing the super-res radar data. Please check with your vendor for availability.

Below are examples of the difference between legacy radar data (left) and super-res (right).

Spanish Version

Synopsis: La Niña is expected to continue through the Northern Hemisphere spring 2008.

Atmospheric and oceanic conditions during February 2008 continued to reflect a strong La Niña. Equatorial SSTs were more than 2.0°C below average across large portions of the central and east-central equatorial Pacific (Fig. 1), and the corresponding weekly values of the Niño-4 and Niño-3.4 indices remained between -1.6°C and -2.1°C during the month (Fig. 2). In contrast, SSTs in the far eastern equatorial Pacific were above average during February 2008, in association with a warming trend that began in mid-December. The upper-ocean heat content (average temperatures in the upper 300m of the oceans between 180° - 100°W) remained below average across the equatorial Pacific during February (Fig. 3), with the largest temperature anomalies averaging -2°C to -6°C at thermocline depth (Fig. 4). Consistent with these oceanic conditions, stronger-than-average low-level easterly winds and upper-level westerly winds persisted across the central equatorial Pacific, convection remained suppressed throughout the central equatorial Pacific, and enhanced convection covered the far western Pacific. Collectively, these oceanic and atmospheric conditions are similar to those accompanying the last strong La Niña episode in 1998-2000.

The most recent dynamical and statistical SST forecasts for the Niño 3.4 region continue to indicate a moderate-to-strong La Niña through March 2008, and a weaker La Niña through April-May-June 2008 (Fig. 5). Thereafter, there is considerable spread in the forecasts, with approximately one-half indicating that La Niña could continue into the Northern Hemisphere fall. Current atmospheric and oceanic conditions and recent observed trends support the likely continuation of La Niña through the Northern Hemisphere spring 2008.

Expected La Niña impacts during March-May 2008 include a continuation of above-average precipitation over Indonesia and below-average precipitation over the central equatorial Pacific. The above average SSTs in the eastern equatorial Pacific may result in increased rainfall over Ecuador and northern Peru, similar to the evolution during the 1998-2000 La Niña episode. Compared to the Northern Hemisphere winter, La Niña impacts over the United States in spring are typically less pronounced. The primary springtime signal for the contiguous United States is an increased probability of below-average precipitation across the South, particularly in the Southeast.

This discussion is a consolidated effort of the National Atmospheric and Oceanic Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts for the evolution of El Niño/La Niña are updated monthly in the Forecast Forum section of CPC's Climate Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for 10 April 2008. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: ncep.list.enso-update@noaa.gov.

Report from Fox News Channel: 

http://www.foxnews.com/wires/2007Sep23
/0,4670,KansasTornado,00.html 

-Rodney 

-Rodney

Report from NOAA..

http://www.noaanews.noaa.gov/stories2007/
s2914.htm

-Rodney