Before 2010 the National Weather Service would issue severe thunderstorm warnings whenever a thunderstorm was forecast to produce wind gusts to 58mph and or hail size 3/4 or greater. Starting January 5, 2010 the hail criteria has increased to one inch with the wind speeds remaining the same. Recent testing by HAAG Engineering in Dallas has shown that most composition shingles can withstand hail impact of up to 3/4 of an inch. When one inch hail was shot at high speeds at these shingles significant damage was noted..
The increase in hail size also addresses the medias request that too many severe thunderstorm warnings where issued, since penny size hail is very common in some parts of the country. The public had become desensitized to the penny size hail severe thunderstorm warnings. The warnings now seem to have more meaning according to user feedback in the Midwestern states. In addition, television networks received fewer viewer complaints from breaking into programming for non-damaging storms.
Other areas of concern are winter nighttime tornado events. Texas and Louisiana recently experienced at least a dozen tornadoes on January 19, 2010. Since tornadoes can happen at anytime, even during the winter months. The National Weather Service will now issue a public severe weather outlook when conditions are favorable for strong or violent tornadoes. The strongest winter tornado activity in the United States is expected along the Gulf coast and over Florida due to El Nino. The Weather Service expects the El Nino weather pattern to continue until at least March.