Weather In Review And Forecast For May 10, 2015

Last week was quite a stormy one. Tornado after tornado on top of flooding rain. It is spring after all and it is May. May is the most active month for tornadoes and severe weather. Last week was no exception. To top it, Tropical Storm Ana made landfall north of Myrtle Beach. It was crazy weather for sure. Here is last week’s severe weather map.

20150511_SevereWeatherMap

Not surprisingly, they are mostly in Texas, Oklahoma, Colorado, Kansas, Nebraska, Iowa, and Minnesota. There were a lot of hail, tornado, and strong winds. Here is the total count of tornadoes, hails, and strong winds from last week.

Tornado: 154
Hail: 391
Wind: 241

There were more tornadoes reported than on April 19 to 26, 2015. However, there are less hail and strong wind reported than on April 19 to 26, 2015. The heat map shows it as well. It is within 50 miles.

20150511_SevereWeatherHeatMap

Severe weather is very hot in the Central US. Again, that is not surprising as cold air clashes with warm air over the Central US. Another factor is upper level troughing in the Western US and upper level ridging in the Eastern US.

20150511_500mb_GeopotentialHeightAnomaly_NH

This type of setups is more favorable for severe weather outbreaks as upper level trough over Southern California and Baja California and upper level ridge over New York and Great Lakes brings moisture from the Pacific and Gulf of Mexico. It was lacking the past spring from 2012 to 2014, which had ridging in the Western US and troughing in the Eastern US. It also played a role in the severe droughts in the Western US. The ridging shunts low pressure systems further north. With the storm tracking more southward than usual due to El Nino, the severe weather have dumped heavy rain that leads to flooding.

20150511_7Day_Rainfall_Total01

The heaviest rain fell over Texas and Oklahoma. The other area that got heavy rain are Kansas and Nebraska and South Carolina and North Carolina. That is from Tropical Storm Ana. The rains were beneficial as areas that are in severe drought got good amount of rain in the past 7 days. Here is a close up of Texas and Oklahoma.

20150511_7Day_Rainfall_Total02

The highest rainfall total is 16 inches, which are in Central and Southern Oklahoma. Some areas south of Dallas saw over 11 inches of rain. It has been very wet up in North Texas and Oklahoma thanks to the severe weather outbreak. It is also helping putting a dent on the drought that has plagued Texas and Oklahoma.

Will this week to next week be like last week? We can look at the past to see what it maybe like. Let’s start with the 6 to 10 day analog forecast.

20150511_6To10Day_AnalogForecast

5/27/1998-Late May 1998 Tornado Outbreak and Derecho on 5/30-31. Spencer tornado is the most destructive and second deadliest for South Dakota, which claims 7 lives. 6 others are from the derecho. The derecho goes across the Great Lakes to the Eastern Seaboard, causing severe weather and tornado outbreaks. It is the most intense thunderstorm for 1998.
6/2/1989-Two tornadoes in Louisiana and Florida claim 5 lives on 6/8.
5/17/1961-Severe weather outbreak on 5/12 to 5/19 in Central and Southern US. Multiple tornadoes, strong wind, and hail reported. No fatalities are reported.
5/19/1962-Rain falls on the first five days of June 1962. Houston WB: 4.12″; Hobby: 3.28″. Houston officially records its wettest 6/4 of 3.72″.
5/24 & 5/29/2007-Heavy rain falls in Southeast Texas between 5/24 to 5/29. 28 tornadoes reported throughout the Midwest and New England between 5/25 to 5/31. String of supercell thunderstorms hit Iowa, Illinois, and Wisconsin. Muscatine, Iowa and Grandview, Iowa are hard hit by the tornadoes. However, not fatalities are reported.
6/5/1980-The Grand Island Tornado Outbreak. 7 tornadoes hit the town of Grand Island, Nebraska on the night of 6/3. It claims a total of 5 lives. A 6th life is lost near Crawfordsville, Indiana. The tornado inspires Ivy Ruckman to write The Night of the Twisters.
6/3/1966-June 1966 Tornado Outbreak Sequence from 6/2-12. There are 57 tornadoes, which claim 18 lives. One tornado hits Topeka, Kansas on 6/8 as a powerful F5 tornado. It claims 16 lives.

Almost all the analog dates had severe weather outbreak somewhere in America. One of them inspired a novel and made for television movie, “The Night of the Twisters”. Let’s look at the 8 to 14 day analog forecast.

20150511_8To14Day_AnalogForecast

5/17/1961-Severe weather outbreak on 5/12 to 5/19 in Central and Southern US. Multiple tornadoes, strong wind, and hail reported. No fatalities are reported.
6/1/1989-Two tornadoes in Louisiana and Florida claim 5 lives on 6/8.
5/27/2007-Heavy rain falls in Southeast Texas between 5/24 to 5/29. 28 tornadoes reported throughout the Midwest and New England between 5/25 to 5/31. String of supercell thunderstorms hit Iowa, Illinois, and Wisconsin. Muscatine, Iowa and Grandview, Iowa are hard hit by the tornadoes. However, not fatalities are reported.
5/18/1962 & 5/23/1962-Rain falls on the first five days of June 1962. Houston WB: 4.12″; Hobby: 3.28″. Houston officially records its wettest 6/4 of 3.72″.
5/27/1998-Late May 1998 Tornado Outbreak and Derecho on 5/30-31. Spencer tornado is the most destructive and second deadliest for South Dakota, which claims 7 lives. 6 others are from the derecho. The derecho goes across the Great Lakes to the Eastern Seaboard, causing severe weather and tornado outbreaks. It is the most intense thunderstorm for 1998.
6/6/1989-Two tornadoes in Louisiana and Florida claim 5 lives on 6/8.
5/26/1995-Great Barrington Tornado or Memorial Day Tornado of 1995. Great Barrington, Massachusetts is hit by a F4 tornado on 5/29. The tornado claims 3 lives, all at Eagleton School.

The 8 to 14 day analog forecast is largely similar to the 6 to 10 day analog forecast. This suggests this week to next week could be a stormy one for America. Based on the analog forecast, this week could be stormy. Severe weather outbreaks are very possible. So, if you see any storm warnings on television and issued by your local National Weather Service, please take them seriously.

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