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Middle Tennessee Nexrad Radar

KOHX Base Reflectivity Loop

  Radar automatically refreshes every 5 minutes.   Last refreshed at

As of 2:10pm, April 24, 2010, WSW now purchases NEXRAD Data in real-time to prevent gaps in radar data during peak events (like todays storms). The raw data is processed on my dedicated weather server by software that generates the custom radar images above. During severe weather, NEXRAD data and the corresponding images are updated every 5 minutes.

Storm Attribute Icons:



Large filled green triangle - Probability of Severe Hail (POSH) >= 50%
Large hollow green triangle - Probability of Severe Hail (POSH) between 30 and 50%
Small filled green triangle - Probability of Hail (POH) >= 50%
Small hollow green triangle - Probability of Hail (POH) between 30 and 50%

NWS Severe Hail equates to 3/4" or larger.


- MESO (Mesocyclone)

MESO will be present if the NEXRAD radar indicates rotation on a slightly larger scale then the TVS signature within a thunderstorm. Mesocyclones are the parent rotation for tornado development. Seen at the surface, a mesocyclone is the wall cloud in the southwest part of a supercell thunderstorm. NEXRAD will indicate "MESO" as color rings if rotation has been detected.

Dashed rings - MESO detection aloft
Arrow rings - MESO detection near the surface

MESO color attributes - The NWS uses a numerical scale of 1/3/5/7/9, where 9 is the strongest Mesocyclone.

1 Very Weak Light Green ring
3 Weak to Minimal Green ring
5 Moderate Yellow ring
7 Strong Red ring
9 Very Strong Magenta ring


 - TVS (Tornadic Vortex Signature)

TVS or ETVS (Elevated Tornadic Vortex Signature) is a signature of a potential tornado indicated by the NEXRAD radar. NEXRAD will indicate "TVS" or "ETVS" if the rotational shear that has been calculated by the NEXRAD radar is judged strong enough that the storm may produce a tornado.The National Weather Service will issue tornado warnings based on the strength of the TVS or ETVS signature.

Inverted filled purple triangle - Tornado Vortex Signature (TVS) detection
Inverted hollow purple triangle - Elevated Tornado Vortex Signature (ETVS) detection