The WSR-88D (NEXRAD) equipment at the Facility is a PUP associated with the actual radar at Mobile, AL   (latitude 30(40'44" north and longitude 088(14'24" west).  The height of the Mobile radar is 289' MSL.

NEXRAD helps identify sea breeze fronts before activity is visible on satellite images through the use of low elevations from Base Reflectivity or Composite Reflectivity products. The front will normally begin to appear northwest through northeast from the center of the radar in the non-precipitable range (below 18 dBz) of return as a thin line of radar return in the range of 1-14 dBz.

Regional use of NEXRAD for severe weather detection is slightly different in the warm, moist, unstable air masses of the southeast region than it is in a region where the freezing level is generally lower. In the local Pensacola area, the hail indicators on the NEXRAD are fairly useless. One alternative method for detecting severe weather was researchedat the Tampa, Florida radar site. It involves using a Vertically Integrated Liquid (VIL) Value of the Day (VOD) determined by the following formula:  1500 ( ((T500(+(T400(), where temperatures are in degrees Celsius.

The formula for both analyzed and forecast temperatures is used at each level, with the average value from each equation used to determine the VIL Value of the Day.

Storms should be investigated if there is a greater than 15 unit change in the VIL in one volume which then exceeds the VOD, or if there is a greater than 20 unit change in the VIL in 2-3 volume scans which then exceeds the VOD. However, if there are four or more pixels that are just below the VIL VOD, would also be investigated, as the VIL VOD has more significance if there is more than one pixel of high value.

For tropical storms and hurricanes, maximum values of the VIL product are normally limited to the mid
20s, with the average values between 5 and 10. This helps to detect embedded thunderstorm activity within the tropical storms, which have associated VILs ranging from approximately 15 to 2. A 50 dBz return or greater above 30,000' is a good indicator of possible severe weather.

Concept Mapping Toolkit
Insitute for Human and Machine Cognition
The University of West Florida