An upper level trough and associated surface low pressure system impacting the Western US will deepen as it digs south over the next few days. As it deepens, the upper level ridge in the east will strengthen and essentially act as a block for the eastern movement of the low. This will result in several days of rain and the potential for severe thunderstorms in the Plain States and snow in the higher elevations of the Rockies.
Severe Weather Threat
As the upper level trough digs south, the atmosphere will become more favorable to support severe weather. Large hail, damaging winds and a few tornadoes will are possible on Friday late afternoon and into the evening. National Weather Service, Storm Prediction Center has identified areas in southeast Nebraska, eastern Colorado, western Kansas, eastern New Mexico and the Texas and Oklahoma Panhandles as having a slight risk for severe weather (outlined in yellow in the graphic below.)
The severe thunderstorm risk shifts south Saturday to primarily be in western Texas.
Along with the risk of severe thunderstorms, heavy rain is also a concern for into the weekend. As the upper level system digs south, it will tap in moisture from the Gulf of Mexico. In addition, the system will draw in Pacific moisture at the mid to upper level at the mid to upper levels of the atmosphere. The Pacific moisture will further enhance the potential for heavy rainfall. Guest contributor, Sheldon Kusselson, provides further insight on the moisture sources that will play a role in this heavy rain event.
The heavier rainfall amounts for Friday Night and into Saturday will mainly extend from central South Dakota south into Nebraska, Colorado and Kansas where 1.5 to 2.0 inches of rain is possible.
The axis is farther south for Saturday Night and into Sunday where the higher risk for heavy rain is from southwestern Nebraska to western Kansas and Oklahoma and into Texas. Widespread 1.5 to around 4 inches of rain will be possible which will be welcomed to help with the wildfires.
Unfortunately, given the slow movement of this system, the precipitation will continue to fall over the same locations in the Plain States and Central Rockies. The 5 day rainfall totals through Tuesday morning show widespread 3 to 6+ inches across much of the High Plains and into Texas. This will potentially lead to flash flooding and river flooding.
For the mountains of Utah, Wyoming, Colorado and New Mexico, the precipitation will be snow and some areas may see significant accumulations. The National Weather Service has issued Winter Storm Warnings, Watches and Advisories for this upcoming storm.
The timing for snowfall accumulations extends from Friday into Sunday Morning. However, the 24 hour period from Friday Evening to Saturday Evening has the higher chances of seeing 6+ inches of snow for Wyoming, Colorado and far northern New Mexico, as noted by the blue colors in the graphic below.
With the threat of severe thunderstorms make sure you have a way to obtain storm for any watches or warnings that are issued for your location. Consider bringing inside toys outdoor furniture, and vehicles that might be damaged by large hail.
With the concern of flooding, remain aware of changes in creeks and streams in your area. If you are traveling, avoid routes that cross rivers and creeks that are known to have flooding problems. If a flash flood warning is issued, follow the advice of your local emergency management.
For those being impacted by the winter weather, use cation if traveling. Double check your car’s winter safety kit and ensure you have extra food and water.
The team at WxIntegrations will continue to provide relevant information and resources to help you better understand and prepare by incorporating weather impacts into your planning and response.