Weather In Review And Forecast For April 26, 2015

20150427 Nepal Earthquake 01

It has been quite an eventful week weatherwise. The deadliest is the Nepalese Earthquake, which claimed about 4,300 lives (at the time of writing) and likely will claim more. I suspect the death toll could exceed 10,000. A large area of Kathmandu, the capital has been leveled. The earthquake was 7.8 on the Richter scale, which is a strong one. The earthquake triggered avalanche at Mt. Everest base camp. The reason the earthquake happened is because the Indian Subcontinent is moving northward. The very reason why we have Mt. Everest, Himalayas, and Tibet. As long as Indian is moving northward, there will be earthquakes and Himalayas and Tibet will get higher.

Back here in America, it has been an active week. Many areas reported tornado, hail, and wind between April 19 to 26. Here is a map of where they happened.

20150427_SevereWeatherMap

Notice, they are mostly over the Southeast and Texas. There are some unusual areas like in California and Oregon. Two tornadoes were reported in Riverside, California, an area not known for severe weather. Here is the total count of tornadoes, hails, and strong winds from last week.

Tornado: 84
Hail: 500
Wind: 835

Quite an active week weather wise. This heat map based on a 50 mile radius shows that most of the active weather happened in Texas and South.

20150427_SevereWeatherHeatMap

Not surprisingly, they are all concentrated in the South. Those regions are most vulnerable to severe weather as it is Spring. So, what allows this type upper air pattern allows severe weather?

20150427_500mb_GeopotentialHeightAnomaly_NH

There is troughing off the coast of Baja California. The troughing sends shortwaves, which are kinks in the atmosphere. These kinks allow severe thunderstorms to develop. There is also ridging over Cuba, which sends in warm and moist air from Caribbean and Gulf of Mexico. They feed into the shortwaves, allow thunderstorms to become intense.

20150427_SurfaceTemperatureAnomaly_NH

The Gulf of Mexico and Caribbean had a warmer than normal week last week. The Great Lakes region had a cooler than normal week. The cool air from the north and warm air from the south also help severe weather to develop as they clash violently.

Last week’s forecast of severe weather was spot on. I was right that we would see severe weather last week. Let’s look at the 6 to 10 day analog forecast to see what this week to next week will be like.

20150427_6To10Day_AnalogForecast

5/9/1982-Tornadoes reported on 5/5-19 in Texas, South, and Midwest.
5/5/2008-Tornado outbreak on 5/1-2 that claims 7 lives in Iowa, Oklahoma, Arkansas, Missouri, Mississippi, Tennessee, Louisiana, and Texas. Series of tornadoes on 5/7-15 in Southern Plains, Southeast, Mid Atlantic. The tornado series claims 28 lives. Heavy rain falls in Houston area on 5/5. Rainfall totals are Intercontinental: 3.47″; Hobby: 0.09″. Second wettest 5/5 on record for Houston.
5/5/1959-Heavy rain falls on 5/10-11. Rainfall totals are Houston WB: 3.09″; Hobby: 2.19″; Galveston: 0.60″. Houston sets an all time rainfall total for 5/11, which is 2.16″. Heavy rain falls on 5/23. Rainfall totals are Houston WB: 3.99″; Hobby: 3.58″; Galveston: 1.09″. Houston sets an all time rainfall total for 5/23.
5/17/1994-Severe weather hits Houston area on 5/13 with strong winds, tornadoes, and hail.
5/4/1969-11 tornadoes hit Texas, Oklahoma, and New Mexico on 5/6. 11 tornadoes hit Texas, Mississippi, Kentucky, and Ohio on 5/8. Another tornado outbreak on 5/10 hits Indiana, Ohio, Kentucky, and Illinois. Heavy rain falls around Cleburne, Texas on 5/6-7. Up to 8″ is recorded in the rain event that leads to severe flooding.
5/3/2006-A series of tornadoes on 5/2-5 in Texas, Oklahoma, and South Dakota. Tornado outbreak on 5/9-10 in Central Plains, South, and Midwest. Severe weather event on 5/14 in the Southeast with hail and tornadoes reported.
4/27/1984-Deadly tornado outbreak strikes Mississippi and Tennessee on 4/21. 15 lives are lost in Mississippi from one F3 tornado. Tornado outbreak on 4/26 strikes Oklahoma, Kansas, Missouri, Iowa, Minnesota, South Dakota, and Louisiana. A total of 12 lives are lost including 8 from a F3 tornado in Oklahoma. Killer Tornado Outbreak on 4/27 in Wisconsin. The tornado outbreak claims 4 lives.

The analog dates I mentioned had a severe weather outbreak to heavy rain. It is spring after all, the severe weather season. Does this mean, we will see tornadoes and flooding this week to early next week? No, but the conditions are there for it. So, what does 8 to 14 day analog forecast hold?

20150427_8To14Day_AnalogForecast

5/10/1993-Tornado outbreak on 5/7 in the Midwest, which claims 1 life.
5/5/1969-111 tornadoes hit Texas, Oklahoma, and New Mexico on 5/6. 11 tornadoes hit Texas, Mississippi, Kentucky, and Ohio on 5/8. Another tornado outbreak on 5/10 hits Indiana, Ohio, Kentucky, and Illinois. Heavy rain falls around Cleburne, Texas on 5/6-7. Up to 8″ is recorded in the rain event that leads to severe flooding.
4/27/1994-Tornado outbreak on 4/25-27 in South, Midwest, and Mid Atlantic region. Two F4 tornadoes are reported near Dallas, Texas and Lafayette, Indiana. The outbreak claims 6 lives.
5/5/1972-Heavy rain falls over Central Texas on 5/11-12. 16.50″ falls in four hours between New Braunfels and Canyon Lake Dam. The flooding claims 17 lives.
4/26/1989-Deadliest tornado ever recorded occurred in Daulatpur and Saturia, Manikganj District, Bangladesh on 4/26. The tornado claims at least 1,300 lives.
4/29/1957-Heavy rain falls in Houston area on 4/27-30. Rainfall totals are Houston WB: 7.56″; Hobby: 4.94″; Galveston: 1.82″. Houston sets rainfall total record on 4/27 (2.72″) and 4/28 (3.76″).
4/30/1991-Tornado outbreak occurs on 4/26 in South Plains and Midwest. 55 tornadoes are reported, which claim 21 lives.

Interesting to note that the 8 to 14 day analog forecast has some major flood events in Texas, which is leading up to May. This is on top of tornado outbreaks. This suggests that May could be a stormy one. Of course, anything can change between now to mid May. Regardless, May should be interesting as severe weather often happens in that month. This week should be quiet for the most part before the activity picks up again by next week. Until than, enjoy the nice weather.

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