Weeralarm V.S. # 4 Extreem weer - Tornado touchdown

32 tornado reports tot nu toe. En de komende dagen nog meer kans op severe weather.

Wild April Weather to be Followed by Wicked May


This map looks a lot like what has been going on during much of April. As a result, May will likely bring more of the same, but also more severe weather farther to the north.

Severe weather experts at AccuWeather.com are forecasting the intense weather outbreaks in the U.S. to continue beyond April into much of May.
According to Severe Weather Expert Meteorologist Henry Margusity, "We see no let-up in the weather pattern that has led to the outbreaks this month."
A pronounced temperature contrast often produces strong storm systems.
May is notorious for severe weather and tornadoes in its own right as warmth builds from the strengthening sun, while the upper atmosphere and the low-level air over the northern latitudes remain chilly.
The jet stream tends to hover close to the temperature contrast.
We cannot say that there is a direct correlation between La Nina and a particular outbreak. However, the ocean water temperature anomaly in the Pacific tends to lead to a strong polar jet stream.
While a strong jet stream is a common occurrence in the spring, the presence of a strong, ongoing La Nina has that strong jet stream on steroids.
A strong jet stream is a key contributor to severe weather and tornado outbreaks.
While the ongoing La Nina may weaken slightly in the coming months, it is still rather strong at present. It could continue to fuel, in an indirect way, frequent strong storm systems and the severe thunderstorms they often breed.
As the chilly air around the Great Lakes, Northeast U.S. and neighboring Canada retreats northward, the risk of severe weather will increase in these areas.
While this too is part of the normal northward progression of severe weather in the spring, the strong La Nina driving the strong jet stream may continue to make severe weather matters much worse than normal.
Two other factors, such as warm, moist air from the Gulf of Mexico and intrusions of dry air from the West, are always players in severe thunderstorms.
The Gulf of Mexico is much warmer than average this spring. The extra warmth translates to higher moisture levels (higher dew points) over downwind areas of the land.
In contrast, the air is extremely dry (low dew points) over southern High Plains as evidenced by the drought and wildfires in the region.
Both of these secondary factors, combined with the strong jet stream may be cranking up the potential energy to be released in the form of violent storms.
It is possible that smoke from the wildfires may be limiting severe weather incidents (and tornadoes) over the favored area of southern High Plains.
However, it may be that the air is just too dry and too extensive in that area, pushing the boundary of the dry and moist air (dry line) farther east, closer to the middle and lower Mississippi Valley.
This boundary is often the fuse for severe thunderstorms and tornadoes.
Throw in the strengthening sun and building warmth to the mix during May and we could really have some ferocious storms on our hands.

Bron: Accuweather

Vandaag weer een moderate risk op severe weather.

quote:

A storm system charging across the Plains will trigger violent thunderstorms from Dallas to Columbus, Ohio today. Most storms will be on the prowl later today and tonight, creating dangerous conditions as the weekend begins.
Feisty thunderstorms rumbled eastward across Kansas overnight into this morning. These storms will continue marching eastward across Missouri today, and a few spotty but powerful thunderstorms will also roam central Texas this afternoon and evening.
However, more widespread dangerous storms will really get going tonight. Overnight, thunderstorms will threaten areas from Oklahoma into the Ohio Valley, erupting as cooler air diving across the Plains clashes with the warm, moist air in place.
A few tornadoes could tear through cities and towns along this swath. Senior Meteorologist Henry Margusity has noted that so far in 2011, the U.S. is on track for making the list of years with the most tornadoes.

Masked by darkness, any twisters that develop will be especially dangerous. Residents of these areas should be sure to have a weather radio on hand to stay apprised of the situation and be prepared to take shelter immediately if necessary.
Wind gusts past 50 mph in thunderstorms will be capable of downing trees and power lines, damaging buildings, and toppling empty tractor trailers. Hail as large as golf balls will pound some locations as well.
Torrents of rain in the storms from Missouri to the Ohio Valley could lead to flash flooding problems. More than 2 inches of rain could douse some locations in this zone in a matter of hours.
Numerous rivers and streams in this area are already experiencing minor to moderate flooding. Additional heavy rain could aggravate existing flooding troubles and even send other waterways surging out of their banks.
Through tonight, Oklahoma City, Dallas, St. Louis, Little Rock, Louisville, Indianapolis and Cincinnati could all lie in the path of one of these vicious storms. Drenching downpours and gusty thunderstorms will continue to menace locations from northern Texas through the Ohio Valley into the first part of the weekend.