Flash flooding will continue to be concern in the southern U.S. and a big cool-down is in store for most of the east by mid-week. CNN Meteorologist Chad Myers has your National forecast for Tuesday.
Meteorologist Chad Myers has potential travel delays, the National Forecast for Tuesday, and an update on the tropics from the CNN Weather Center.
Severe weather is expected in the Plains today and Tuesday, but Wednesday could steal the spotlight this week. Cold air from Canada, clashing with warm and moist air from the Gulf and combining with dry air from the Desert Southwest could combine to produce a potentially deadly and widespread severe weather outbreak by mid-week. “There is the potential for a significant weather event Wednesday,” Bill Bunting, Chief of Operations at the Storm Predication Center said. Severe storms could spawn tornadoes, damaging winds and destructive hail across Oklahoma, Kansas and Missouri. The outbreak could continue into Thursday and Friday as the system punches eastward.
The Storm Prediction Center issues several forecasts highlighting the probability for severe weather several times a day. These forecasts are called Convective Outlooks. The outlooks highlight the probability that an area will experience severe storms up to eight days in advance. These probabilities fall into three categories: high, moderate and slight. High risk days usually indicate an extreme severe weather event is in the forecast. In most cases, it indicates a major tornado outbreak could occur.
Weather forecast models were already coming into good agreement early this morning indicating a severe weather outbreak could happen by mid-week. It is unusual for most of the models to predict such a severe weather event this early. After seeing the models were in agreement, forecasters at the SPC decided to issue a moderate risk area for severe storms on Wednesday in this morning’s outlook. That’s three days in advance. Issuing a moderate risk for severe thunderstorms this far in advance is rare for the SPC. Including the moderate risk area issued today, only five moderate risk areas have been issued three days in advance in the past 10 years during the month of April, said Bunting.
One of those times occurred in advance of the largest tornado outbreak in U.S. history. The outbreak commenced April 25, 2011. 358 tornadoes touched down across the U.S. during a 3-day period. Tornadoes and severe weather caused over 300 fatalities and approximately $11 billion in damages. During this outbreak, a large, violent tornado swept through Alabama, causing destruction in Tuscaloosa and the University of Alabama. The twister also caused 1,500 injuries and 65 fatalities. It was 1.5 miles wide when it crossed Interstate 65 and stayed on the ground for an astounding 80 miles.
Moderate risk areas issued three days in advance also occur outside of the month of April. In the past 10 years, 12 moderate risk areas have been issued three days prior to a severe weather outbreak. Moderate risk forecasts that are issued two days in advance are more common. In January of this year, a moderate risk area was issued two days before an unusually strong weather system triggered a severe weather outbreak that resulted in 57 tornadoes across the South and Midwest.
CNN Meteorologist Melissa Lefevre contributed to this report.
CNN Meteorologist Chad Myers explains the reason behind all of the severe weather this week. Chad will have the latest forecast on CNN Newsroom tomorrow.
by CNN Meteorologist Judson Jones
Blinding snow and temperatures that are 40 degrees below average does not sound like spring in Denver. On the flip side, the 20 degree above average temperature forecast for New York City feels more like early summer.
But the unexpected is what we expect in spring.
It is the greatest transitional season of them all, when cold Arctic air clashes with the rising warm, moist air from the Gulf and dry, warm air from the Desert Southwest.
The drastic change in temperature is a major factor that aides in the development of thunderstorms across what is known as Tornado Alley.
Tuesday, central Oklahoma is under the gun. There's a moderate risk of hail, damaging thunderstorm winds and tornadoes over about 17,000 square miles.
On average April is the second most active month for tornadoes in Oklahoma. In 2012, 53 tornadoes touched down in April. That's the most tornadoes ever recorded for the month of April. In 2011, the state had 50 total tornadoes for the month of April.
While Oklahoma could still shatter the record breaking trend for tornadoes this month, Denver won’t even get close to touching their April record snowfall of 23” set in 1885.
Meteorologist Melissa Lefevre contributed to this report.