Weather In Review And Forecast For April 19, 2015

It hard to believe it is now mid April of 2015. So many tragic anniversaries occur between April 14 to April 20 ranging from Titanic, Grandcamp Explosion in Texas City, San Francisco Earthquake, Branch Davidian Siege, Oklahoma City Bombing, Columbine, Virginia Tech, West, Texas Explosion, and Boston Marathon Bombing. The weather world was also active. Severe weather plagued Texas from April 16 to 19. It was also a very wet from heavy rain. Rain that is beneficial in nature.

20150420_SevereWeatherMap

20150420_7Day_Rainfall_Total

Looks like weather forecast looked to be correct. Severe weather did occur like it occurred around those analog dates from last week. What would allow severe weather to happen last week. One can look at upper air patterns. In terms of rain, the forecast model got it right where the heaviest rain will fall, Southeast Texas and Louisiana. The highest 7 day total is over 9 inches of rain. Many areas saw 2 to 6 inches of rain.

20150420_500mb_GeopotentialHeightAnomaly_NH

There is upper air ridging over the Northeast, while there is troughing over New Mexico. The ridging brings in warm moist air from the Gulf of Mexico and the trough brings upper air disturbances to set fire off thunderstorms that produce severe weather. It is also from Pacific fronts, which serve as cool fronts, which also help fire off more thunderstorms as the warm air clashes with cool air.

20150420_SurfaceTemperatureAnomaly_NH

It was unusually warm over the Gulf of Mexico that helped foster severe weather last week. The air is also humid, which allows storms to be even more intense and dump heavier rain. The big question is, will this week be like last week? Let’s look forecast models. Special thanks to Levi Cowan of Tropical Tidbits as usual.

20150420_EURO_MSLP_120Hour_1200Z

20150420_GEM_MSLP_Precip_108Hour_1200Z

20150420_GFS_MSLP_Precip_96Hour_1800Z

20150420_NAVGEM_MSLP_Precip_102Hour_1800Z

Most forecast models show a surface low north of Houston between Friday afternoon to early Saturday morning. The EURO is the northernmost track and fastest moving with lowest pressure of 995 millibars. NAVGEM is the southern most, while GFS and Canadian are about the same. None of the models have severe weather over Houston area. However, it is too early to tell at this time as things can change at a whim. Severe weather is quite unpredictable like a cat like I see with rainfall total for the next 7 days.

20150420_GEM_AccumulatedPrecipitationTotal_USA_168Hour_1200Z

20150420_GFS_AccumulatedPrecipitationTotal_USA_168Hour_1800Z

The rainfall forecast has less rain than last week at this time. I would rule out heavy rain again with severe weather later this week. Canadian as 0.50 to 1.50 inches of rain, while GFS has 0.50 to 4.00 inches of rain. Quite a wide difference between Canadian and GFS. I consider this a low confidence forecast. When I see consensus among the forecast models, I consider it high confidence forecast. Of course, it is not 100 percent accurate, but it does come to fruition.

Another forecast model I like to use are analogs and they have proven to be accurate for the most part, whether it is 6 to 10 days or 8 to 14 days analog forecast. Here is 6 to 10 day analog forecast.

20150420_6To10Day_AnalogForecast

4/12/1963-A strong F4 tornado develops in Essex in Kankakee County, Illinois and travels 57 miles eastward into Medaryville in Pulaski County, Indiana. The tornado damages Olivet Nazarene University in Bourbonnais, Illinois. Only 1 person is killed in the tornado.
4/23/1969-Deadly tornadoes strike Bangladesh on 4/14. One tornado near Dhaka claimed 660 lives, while another east of Comilla claims 263 lives. A total of 923 people are killed in Bangladesh.
4/21/1971-Tornado outbreak in Alabama and Georgia on 4/23. The outbreak claims one life from 11 tornadoes. 14 tornadoes hit Missouri, Illinois, Indiana, and Kentucky on 4/27. The outbreak claims 6 lives. Another outbreak occurs in North Texas on 4/28 with 9 tornadoes, but no fatalities.
5/10/1977-Tornado outbreak on 5/4 in Missouri, Kansas, Iowa, Nebraska, Minnesota, and Indiana. There is a major tornado outbreak in Kansas City area. The outbreak claims a total of 3 lives.
4/16/1962-Heavy rain falls ahead of a cold front on 4/30-5/1. Rainfall totals are Houston WB: 3.01″; Hobby: 0.85″; Galveston: 0.48″. The 2.04″ on 4/30 makes it the second wettest on record for that date.
4/20/1983-Tornado outbreak on 5/1-2. 63 tornadoes are reported in 11 states claiming 7 lives.
4/16/1979-Red River Valley Tornado Outbreak on 4/10-11. 59 tornadoes in Texas, Oklahoma, Kansas, Arkansas, Missouri, and Indiana. One of them, a F4 tornado ravages Wichita Falls area and claims 42 lives. A total of 58 lives are lost in the tornado outbreak.
4/29/1971-14 tornadoes hit Missouri, Illinois, Indiana, and Kentucky on 4/27. The outbreak claims 6 lives. A tornado outbreak occurs in North Texas on 4/28 with 9 tornadoes, but no fatalities.
5/6/1980-Kalamazoo is hit by a F3 tornado on 5/13. It claims 5 lives and causes massive damage in Kalamazoo and surrounding areas.

Looking at those analog dates I listed, most had tornado outbreaks. One had heavy rain. If we were to use the 6 to 10 analog forecast, this suggests someone in America may get hit by tornadoes. Does this mean it will happen? No, but the conditions are conducive for tornadoes to form in America in the next few days. Let’s look further with the 8 to 14 days analog forecast.

20150420_8To14Day_AnalogForecast

5/5/1951-A power F4 tornado hits north of Olney, Texas on 5/18. The tornado claims 2 lives.
4/26/1976-Tornado outbreak on 4/19-21 in Texas, Oklahoma, Louisiana, Arkansas, Missouri, Wisconsin, Michigan, and Kentucky. The outbreak only claims 1 life. There is a F5 tornado reported north of Brownwood, Texas.
5/3/1957-Tornado outbreak occurs on 5/15 in Texas and Oklahoma. A F4 tornado strikes Silverton and claims 21 lives. 12 tornadoes are reported in this outbreak and claims a total of 22 lives.
4/16/1979-Red River Valley Tornado Outbreak on 4/10-11. 59 tornadoes in Texas, Oklahoma, Kansas, Arkansas, Missouri, and Indiana. One of them, a F4 tornado ravages Wichita Falls area and claims 42 lives. A total of 58 lives are lost in the tornado outbreak.
5/10/1977-Tornado outbreak on 5/4 in Missouri, Kansas, Iowa, Nebraska, Minnesota, and Indiana. There is a major tornado outbreak in Kansas City area. The outbreak claims a total of 3 lives.
4/24/1971-14 tornadoes hit Missouri, Illinois, Indiana, and Kentucky on 4/27. The outbreak claims 6 lives. A tornado outbreak occurs in North Texas on 4/28 with 9 tornadoes, but no fatalities.
4/23/1969-Deadly tornadoes strike Bangladesh on 4/14. One tornado near Dhaka claimed 660 lives, while another east of Comilla claims 263 lives. A total of 923 people are killed in Bangladesh.

The 8 to 14 day analog forecast is pretty much the same as 6 to 10 day analog forecast. The main issue is severe weather outbreaks, including tornadoes. This is spring after all when tornado activity picks up. Based on the analog forecast, this week to next week could see severe weather, especially by the end of the week. This week should be interesting.

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