Observers may have noted that public data feeds of Level 3 (and other data types) have been slow to erratic over the last month or so. Level 3 is what EWR uses for the “B” scans on the main project page.

Recently the NWS upgraded the resolution of some of the products obtained from the radar sweeps. This has resulted in a significant increase in bandwidth required to dispense these products from the NWS public servers, with the result that at times data updates are late, or even missing.

The issue is being addressed by re-farming the servers. The upgrade is required to be completed by July 4, but the storm conditions in the Gulf of Mexico may get in the way. Efforts are being made to complete this work quickly, as the approaching hurricane season may hamper the process if it cannot be completed expeditiously.

In terms of the scans presented by EWR in SCAN B and the supplements, the standard offering is Composite Reflectivity (CR) on the web page as it loads, and Base Reflectivity .5 degree (the lowest scan tilt) (BR1) on the “click on image” option. The Base Reflectivity data comes off the scan early and is sent out early, as it is the most important reflectivity scan for mesocyclonic weather (ie tornados). The Composite Reflectivity scan is the sum of each of the upward scans, and therefore comes off the scan cycle later.

If CR data is significantly behind (30 minutes or more), click on the image to view the Base Reflectivity scan – it may be more current than the CR scan. Its also good practice to switch between the two scans when tornadic weather is threatening. Composite Reflectivity products, while showing the extent and range of the whole atmosphere, may mask tornadic events if there is signifcant weather above the first tilt level. BR1 covers the vertical area to about 15,000 feet, and ignores the rest above, so tornadic weather signatures may be clearly seen that are otherwise masked by the composite scan.

Hopefully the NWS will be able to resolve this issue quickly.

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