Inaccurate Weather forecast in Weather app

[ThrowerGB]

Please let's stop using the term "weather service" when we're talking about "weather apps. They're different things. The term "weather service" usually refers to the official government (national or regional) source for weather forecasts and current or past observations. Virtually all "weather apps" get their information directly from either official national or regional weather services, or from third party intermediary providers who get the information from the official sources and package and/or interpret it for use by weather apps. The primary advantage of weather apps is the way they present the information. However the direct government sources usually are the most accurate and fastest at showing forecasts and warnings of severe weather.
Here in the U.S., weather.gov is the primary site for information from the U.S. National Weather Service (NWS).
In Australia: the Bureau of Meteorology (BOM) site is bom.gov.au.
In the U.K.: the Met Office site is www.metoffice.gov.uk
However it's different in different countries. European countries get together to fund the European Center For Medium-Range Weather Forecasts (ECMWF). With national weather services using that information tailored to their specific national requirements
Finally: the term "Weather Enterprise" has been developed and used in the U.S for quite a few years now to recognize that weather forecasting is a partnership of those supplying observations, maintaining archives of historical weather related information, conducting research to advance the science. Official government government analysis, forecast and warning organizations, and private sector services compete with each other to package the information from the government, and other sources to satisfy the needs and preferences of the many consumers of weather information. It's been found in the U.S. that the collaborations of the Weather Enterprise provide the most effective way to get timely information to weather consumers based on the best science and systems.
Clearly, with so many weather apps, TV, radio, and social media weather providers, there will be some who do it better than others and some not so good. But be aware that what comes from national weather services is generally the best in terms of timeliness, accuracy, use of the best science, and is the official government source. With respect to weather apps, there are many choices depending on where in the world you live. Look at several apps, ignore any marketing hype, choose one or two that suit you best, and include links to official government sites.

 

[msackey]

I paid for the original Dark Sky app and would gladly pay another $10 just to get the dark sky app + service back.

I used to like Dark Sky and paid for it too. But in the recent years before it was sunset, it was super inaccurate regarding rainfall prediction.

 

[zerogoaler]

The MacOS and iOS weather app, after cannibalizing Dark Sky, is shockingly inaccurate with our forecast. Here in Michigan, we had a bad ice storm last week. Instead of predicting ice, the Apple Weather app predicted something like 21 inches of snow. The Apple generated forecast was also discrepant with the National Weather Service storm warning that was issued, that was much more predictive of what transpired.

We have another weather event scheduled for Friday. Most other services are predicting a mix of snow and rain. Apple is predicting 13 inches of wintry mix.

What gives? The Apple Weather app before gobbling up Dark Sky was accurate. Dark Sky was awesome and now is supposedly embedded in the new Weather app, but they are grossly misrepresenting precipitation expected amounts. I really dislike the weather channel app, but I don't feel I can trust Apple's Weather app. How can we prevail on Apple to fix this serious flaw?

I do not understand why apple weather is so useless. Right now it shows heavy snow for my ski area and I am looking at it and there isn't a cloud in the sky in 25 miles, and the ski area webcam shows perfect sun and 25 mils+ visibility..

 

[DotCom2]

The The weather app here is off by as much as 10 degrees sometimes. It's useless!

 

[ThrowerGB]

A week ago we had a storm roll through that was entirely rain and Apple predicted 20" of snow. We got 0". It was an inch of rain.
Two days ago it predicts another dumping. What'd we get? Half inch of rain.
Friday we have one coming in that is going to be mostly rain again and here Apple weather is predicting 8" of snow?

It's just absolutely awful at precipitation projections. What's even the point if you're gonna be that far off? My group chat has been mocking the forecast every couple days. It's way off every other forecast and always wrong.

The rule of thumb for comparing depth of new snow depth vs rain is 10" of new snow is about 1" of rain. But the ratio varies from event to event. New snow is snow that has fallen on snow that has already been measured. i.e., new snow + old snow = total snow depth. Observers will usually measure the depth of new snow and then melt it to get the equivalent amount of liquid water.
@mnsportsgeek's comment above gives some useful examples of snow depth vs rainfall equivalent ratios.
In the first example above, the 20" of snow was roughly equivalent to about an 1" of rain, hopefully not too far away from the 0" of rain. i.e., a nice example of a 20:1 ratio. But not quite, because the two measures of 20" and 1" aren't at the same location.
The second example of a "dumping" vs half an inch of rain is an example of the ratio varying; roughly 2 dumplings:1. (Sorry I couldn't resist that.)
I can use the third example to mention why the term "rainfall equivalent" is useful. When snow melts and becomes liquid water, we might want to know how much water we got on our corn crop, or to fill the dam, or to gather together becoming a flood.
Note: Snow, ice, hail and rain are all just water in various states from solid frozen water (ice & hail), water frozen into individual snow flakes with many many different shapes of individual flakes (snow). Rain, of course, is liquid water. In hail storms, rain drops can move upwards in the atmosphere (driven by updrafts) where it's colder and can freeze into hail (or hail stones). As the frozen raindrops (hail stones) are driven up and down by the different drafts in thunderstorms. Raindrops collide with hail, freeze on the hail stone and make it bigger. Large pieces of hail, (golfball and football size for example) start out as individual frozen drops of rain that get bigger and bigger as many rain drops hit the hail stone and freeze on it as the hail stone moves up and down in the storm.
When it's just a little bit below freezing to above freezing, snow flakes will change shape and stick to each other, releasing heat energy. (There's complicated chemistry and physics involved if you want to follow up on how snow flakes evolve.)
However at temperatures well below freezing, the flakes don't stick together.

 

[ThrowerGB]

Be careful. We know weather changes at different times in the future. Good forecast apps will clearly define what time in the future the forecast applies to. It may be a daily forecast for tomorrow describing varying conditions throughout the day, or a daily forecast for 3-days in the future. It may be a series of daily forecasts for each of the next ten days, or perhaps a rainfall forecast for each of the next eight, 6-hour intervals, accompanied by each of those 8 combined into a single 48-hour forecast for the total rainfall in the next 48 hours.