Aviationweather.gov HEMS Tool

[ridethisbike]

Wondering if any of you guys use it. Up until finding this tool a lot of my weather decisions have been based on METARs and the nearest TAF to my destination, along with various non-aviation related websites forecasting, radar, and prognostic charts.

 

I'm surprised they actually named it a HEMS tool when literally EVERYONE can benefit from its use.

 

My main question is accuracy of flight categories between weather stations. Can anyone chime in on that one?

 

I've literally seen it show IFR between two stations that were on the edges of that IFR depiction. Granted, looking at it made sense because I know a mountain was on the windward side of the IFR area, and it was saying that ceilings were causing the IFR conditions, but that's only one instance.

 

I'm sure the tool has been on the website for a while, but I've never once even noticed it. For those of you that haven't seen this seriously awesome tool, you can find it by going to aviationweather.gov, clicking/hovering your mouse over the "Tools" menu at the top, followed by a click on HEMS Tool.

 

Conversely, you can go here: www.aviationweather.gov/hemst

Edited June 5, 2015 by ridethisbike

[Gomer Pylot]

The replacement for this is the flight path tool. Both are similar. I've seen them reporting weather far different from what I was seeing, or even being reported at a weather station. I use it as a no-go tool only, and never rely on it for a go decision. It's good for quick looks, but you need to keep current with the actual conditions and what it's reporting to get an accurate picture of the weather. It's better than nothing, but it's far from perfect. Weather reporting via METARs can be iffy also. I remember seeing an airport in our area that reported a 100' ceiling for months, and the HEMS tool showed IFR around it full time. The ceilometer had malfunctioned, probably had bird poop on the lens, and it took a very long time to get it fixed. I saw programs decline flights to the area based on that report, when I knew the weather was actually fine, and took a couple of flights even though the report was bad, and my worst weather problem was sun in my eyes. You have to know your area of operations, and the weather tendencies in it.

 

Like I said, it's better than nothing, but never trust it completely. Use it to decline a flight if you want, but remember that even if it says the area is VFR, it might be lying to you.

[Matt321]

I used it years ago when it first came out but quickly found it unreliable. Whatever algorithms some smarty pants programmed in dont do a great job. Local knowledge and standard observations and forecasts are much better as Gomer said.