Monday, July 7, 2008

July 7 Severe Weather

5:10 PM Update: A line of thunderstorms, some severe and tornadic, continue to occur along a line from near Decorah, IA southwestward to near Council Bluffs, IA. These storms should continue to be able to produce damaging winds and large hail up to one inch in diameter. At times throughout the evening, some storms may be able to become tornadic within the line segments. Currently one such storm is occurring near Stratford, IA or within Webster and Hamilton counties. Those along this line or to the southeast should continue to monitor conditions as the storms will work their way towards them this evening and into the early overnight hours.

-------------------------------------------------------------------------------------

3:30 PM Update: Severe thunderstorm watch continues for portions of northern Iowa until 9 PM. Thunderstorms have continued to travel into portions of southeastern Minnesota as a bow echo, with damaging winds in excess of 60 mph. The tail end of this line of storms near Mason City has since also became severe, and tornadic with a warning now issued for Cerro Gordo county. Ahead of this, a severe thunderstorm warning was issued for portions of Floyd and Mitchell counties for the threat of damaging winds. Continued development of storms is likely throughout the afternoon, with the best potential over northeastern Iowa.

-------------------------------------------------------------------------------------

12:05 PM Update: Another interesting and potentially complex situation for severe weather across the state of Iowa again today. A subtle surface boundary currently exists across northern Iowa, which combined with a low level jet increase this evening, along with additional lift created by subtle low pressure near the IA/MN border this evening should create a situation for severe weather. Currently, abundant cloud cover and scattered showers/thunderstorms exists over northwest Iowa. Behind this, clouds are clearing and will allow temperatures to warm rapidly created a strong unstable environment.

Expect thunderstorms to initiate across southern Minnesota, and northern Iowa along/near the frontal boundary during the later afternoon and evening hours. These storms could rapidly become severe, capable of both large hail and damaging winds. The slight difference between yesterday's and today's event will be the additional shear that is present today. This may allow storms to remain more discrete today, thus increasing the tornado potential along the boundary from western IA/MN into Wisconsin. More updates on the severe weather potential is possible later in the day as the threat becomes defined.

0 comments: