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Identifying Freezing Rain on Nexrad

Moderated by: rkaplan   New Topic Reply Print Author Post rkaplan Administrator Joined:  Sun Jan 22nd, 2006 Location:  Uniontown, Pennsylvania USA Posts:  399 Status:  Offline  Posted: Sun Feb 12th, 2006 03:17 am Quote Reply I find Intellicast Nexrad radar (http://www.intellicast.com) to be very helpful as a source of Nexrad which is digitally processed very well.  Note that not all Nexrad images are the same -- there is a lot of image processing involved (both subjective and objective) in order to combine data from multiple radar sites/altitudes and present it in a format that is easily used by pilots. Take the example below.   This Nexrad image has been color-coded to depict frozen, non-frozen, and mixed precipitation.  The areas of pink reflect mixed precipitation or multiple freezing layers and these pink areas are particularly high-risk for freezing rain or severe icing.   Attachment: freezingrain.jpg (Downloaded 134 times) ____________________ Richard Kaplan, CFII rkaplan@flyimc.com http://www.flyimc.com rkaplan Administrator Joined:  Sun Jan 22nd, 2006 Location:  Uniontown, Pennsylvania USA Posts:  399 Status:  Offline  Posted: Sat Feb 18th, 2006 01:54 pm Quote Reply This is an interesting example of the same concept which shows how different Nexrad sources can depict weather very differently. On top is a national Nexrad image from Intellicast (http://www.intellicast.com) -- my personal favorite Nexrad site -- which shows areas of frozen, non-frozen, and mixed precipitation.  On the bottom is an image from the ADDS service (http://www.aviationweather.gov ) which filters away less intense precip.  As you can see, ADDS does not show any precip at all in Southern Ohio whereas Intellicast shows this clearly. Weather depicted on ADDS is almost certainly significiant precip, whereas weather depicted on Intellicast might just be light precip aloft.  The difference in presentation is substantial.  Personally I prefer to use Intellicast to get the worst-case big picture and then use other sources to decide how significant the precip may be.     Attachment: frozen.gif (Downloaded 119 times) ____________________ Richard Kaplan, CFII rkaplan@flyimc.com http://www.flyimc.com rkaplan Administrator Joined:  Sun Jan 22nd, 2006 Location:  Uniontown, Pennsylvania USA Posts:  399 Status:  Offline  Posted: Sat Feb 18th, 2006 02:18 pm Quote Reply This is another comparison a few hours later comparing the Intellicast site (http://www.intellicast.com ) with WeatherTap (http://www.weathertap ).  Weathertap is a subscription site  but I find its echo tops data and lightning network data to be very helpful. The top view again shows snow in Southern Ohio and West Virginia.  The bottom view shows minimal active precipitation in these areas.  Most likely this means the tops are low although on rare occasions there can be high clouds with no precip.   What is most important is to compare weather from multiple graphical and text sources, not relying on any one source. Here are some corresponding PIREPs for the region: OH CLE UA /OV CLE/TM 1312/FLUNKN/TP CRJ7/SK OVC030-TOP055/CA/IC     NEG/RM DURGC CLE= PA PIT UA /OV MMJ090020/TM 1345/FL090/TP C208/SK TOP090/TA M18/IC     TRACE-LGT RIME BLO 090/RM DURGC=   Attachment: tops2.jpg (Downloaded 110 times) ____________________ Richard Kaplan, CFII rkaplan@flyimc.com http://www.flyimc.com  Current time is 02:48 pm

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