Record Warmth and Severe Storms – Dec. 11, 2015
A strong and warm mid-level ridge over the Gulf of Mexico, combined with a large surface high pressure off the East Coast, will produce warm southerly winds across the eastern half of the U.S. this weekend. These weather factors will produce temperatures 15-30 degrees above mid-December normals, which will cause many daily record highs to fall on Friday, Saturday and Sunday.
A severe weather outbreak is expected this weekend as many of the typical severe weather ingredients will come together to make this happen.
1. A strong upper-level low to provide rising air
2. Strong low/mid-level jet streams to provide shear
3. A strengthening northeastward-moving surface low
4. Low-level southerly winds to provide moisture
Saturday’s severe weather chances are in yellow shading and Sunday’s severe weather chances are in orange shading.
Though there is a threat for a few tornadoes this weekend, a squall line producing severe and damaging winds is the most likely threat–evident by looking at 15km BAMS precipitation rate at 7 p.m. on Saturday. Most likely areas affected by severe weather on Saturday will be central/eastern Texas and eastern Oklahoma.
The same severe model is expected on Sunday, as well. There will likely be a strong eastward-moving squall line producing damaging winds that will move through the Mississippi River Valley eastward to the Tennessee River Valley.