National Weather Service United States Department of Commerce

Strong Thunderstorms and Heavy Rain Possible

A frontal boundary stretching from New Mexico across Texas and into the Gulf Coast will be the focus for strong to severe thunderstorms. Heavy rain, with local flooding is also possible in these areas. A low pressure area near the Carolina coast may also bring heavy rain and local flooding. Read More >

When the National Weather Service is Watching Radar...

When there is severe weather across central Alabama, it is the meteorologists of the Birmingham National Weather Service (NWS) office in Calera, AL, who are issuing Flash Flood (FFW), Severe Thunderstorm (SVR) and Tornado (TOR) Warnings. In an effort to better help the citizens of central Alabama understand exactly what we are looking for when we are watching the radar, we have created this page. Along with an explanation of how the radar works, we will highlight certain features of recent storms in order to illustrate what we are looking for when making the decision whether or not to issue a warning. No feature stands alone when making the decision to issue a warning; it is a combination of multiple features which helps us make that decision.

Introduction

How does the Radar work?

Information the Radar Shows us

Dual Polarized Technology

Key Indicators in Warning Decisions

Short-comings
of the Radar
 

 

 

May 3 Reflectivity
May 3 Velocity

 

The radar images shown are of a supercell thunderstorm that produced multiple tornado tracks through St. Clair
and Talladega counties on May 3, 2009. The reflectivity is on the left and velocity is on the right.