Thursday, February 4, 2010

Understanding Winter Weather Advisories & Warnings...

I know there has been some confusion on the watches, warnings, & advisories from the National Weather Service. It does vary from office to office which also adds to the confusion. For Indianapolis, the criteria for a Winter Storm Warning is 6” in 12 hours or 8” in 24 hours. For a Winter Weather Advisory, it is 3-5” in 12 hours.

For a Wind Chill Advisory, it is -15 to -24 and a Wind Chill Warning it is -25 of colder.

A watch is just that and usually an advisory or warning follows. Watches for winter weather are usually issued 36 hours or more in advance.

When the advisory or warning criteria is not met, then a Special Weather Statement is issued.

This information and much more detail can be found in this NWS Directive.


matt said...

I know you like to remain conservative with your snow fall forecast, but between you and me what do you expect from this storm? Do you see any NW trend bring more snow up this way from SE indiana? I know there is always uncertainty with any snow storm.BTW did you see wishTV's forecast? LOL

Jim said...


I don't see anything leading me to believe it will trend NW. I did not see the WISH TV forecast but saw the WTHR and they had the snow totals reversed. opps...

I *wish* we could see a trend north or even the low to stall out for a few hours so we could be buried but that is just a wish and will have to nowcast it rather than forecast it.