Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.
By: Christopher C. Burt , 7:50 PM GMT on April 29, 2014
Wild Week of Weather for the U.S.
After a relatively quiet first three weeks of April weather-wise, the past five days have made up for lost time. Top of the list, of course, has been the deadly tornado outbreaks on April 27-28. In addition, heavy snow in the Rockies and Black Hills has also occurred as well as some extreme heat and amazing rainfall and hail events.
As of midday April 29th, the death toll from the tornadoes on April 27th and 28th officially stands at 34. There were at least 97 tornado reports over the two-day period but some of these may have been reports of the same storm so the actual number of tornadoes that formed was probably less than this. Jeff Masters has posted a detailed blog about the tornado events today (April 29th) already so I will not go into further details about the event (other than to note that since he posted his blog the two-day death toll has now increased from 29 to 34).
An aerial view of some of the damage caused by a tornado in Mississippi on April 28th. It is expected that at least one of the tornadoes to hit the state was of EF-4 intensity. NBC News.
As usual, very large hail accompanied many of the super cells that produced the tornadoes, with 1”-2.5” diameter hailstone reports being common. However, it was a storm in Mississippi last Friday (April 25th) that was particularly noteworthy. Observers in the town of West in Holmes County, Mississippi reported hail up to 4.25” in diameter. Although Mississippi does not officially keep track of record hailstone size events (as a handful of other states do, (see this blog for a list of such), the 4.25” figure would be the largest hail ever observed in Mississippi if the estimate was accurate. The previous largest hailstone report from the state was a 4.0” monster that fell on Batesville during the catastrophic tornado outbreak of April 27, 2011.
A map of the hail streak that hit Holmes County, Mississippi on April 25th and the accompanying hail report. From hailtrends.com
Corpus Christi, Texas recorded their hottest temperatures ever measured during the month of April on the 27th and 28th with 103°F (39.4°C) readings both days. The previous April heat record was 102°F (38.9°C) set on April 23, 1955 and also on April 26, 1984. Laredo, Texas reached a scorching 109°F (42.8°C) on April 27th which, though amazing, fell well short of their April heat record of 112°F (44.4°C) also set on April 27th back in 1937.
Heavy late April snowfall is not uncommon to the Rocky Mountain States or the Black Hills of South Dakota but is worthy of mention since it occurred simultaneously with the heat and tornado events of the past several days. Some sites in the Black Hills, like Lead, have measured up to 24” of snow since Sunday (and 15" in Deadwood) and it is still snowing where an additional 4-8” is expected today (April 29th). Heavy snow accumulated in the Colorado Rocky Mountains over the past weekend with one to two-foot depths common. Red Mountain Pass reported 30”. Snow flurries and showers also invaded portions of central Nebraska and Kansas on Monday April 28th on the backside of the powerful low pressure system that was responsible for the severe weather outbreaks to its east. Places that reached near 90°F (32.2°C) on Saturday (April 26th) in Kansas saw some snowflakes just a few days later, as was the case in Goodland, Kansas that went from 86°F (30°C) on Saturday to light snow and temperatures in the mid-30°s this Tuesday morning (April 29th).
Some of the severe storms that plagued the south-central and southeast portions of the country also brought torrential rainfalls and local flooding problems. Locations in northeastern Arkansas and southern Missouri saw 5”-6” of rain fall in a 24-hour period Sunday-Monday. The most impressive report, however, was the 4.00” of rain that deluged Mobile, Alabama in one hour Tuesday (April 29th) morning between 2 a.m. and 3 a.m. The storm total so far for the day has been 8.99”. Late reports now indicate 5.68" in one hour at Pensacola, Florida between 8:53 p.m-9:53 p.m. on April 29th with an estimated 15.50" daily total although the gauge only actually only measured 11.13" prior to failing around 10:30 p.m. April 29th. The data from Pensacola Airport ceased to report after this hour. At least one fatality has been reported due to flooding in the area. According to the estimated 15.50” at Pensacola on April that NWS-Mobile now has published, the Pensacola April 2014 monthly rainfall stands at 24.61” (this does not include any precip that fell on April 30th). Nevertheless, 24.61” would surpass the previous all-time monthly record (for any month) for Pensacola which was 24.46” in April 2005.
Also, depending on how much rain fell between the 5:53 a.m. April 29 and 5:53 a.m. April 30th the all-time 24-hour record of 17.07” on October 4-5, 1934 may have been broken, assuming that at least an additional 1.57” fell between midnight April 29 and 5:53 a.m. April 30th.
A photograph of street flooding in downtown Mobile during the intense rain event early morning on April 29th. Image tweeted to NWS-Mobile.
More severe weather is expected today and Wednesday, April 29th-30th in the Southeast.
Christopher C. Burt
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