Update: We have now received a note from Weather Flow's creator Gergely Orosz on why the app has been removed. In short, it's because of a lack of revenue due to his weather provider increasing its fees:

"My weather provider - Weather Underground - hiked their prices to a level where the app started making a significant loss that I couldn't fund after a while. Their weather data is expensive - $1,500 / month and the app was bringing in significantly less revenue then this, the last month it was $500, with the purchases also starting to go down. After a while the difference got too much to keep paying out of pocket without much hope of breaking even (not making a loss) again. Unfortunately weather data is expensive with lots of hits per day (Weather Flow was making almost 1M requests/day due to live tile updates) and I can't see a cheap or free, but decent alternative data source."

Original story: One of our favorite weather apps for Windows Phone, Weather Flow, is no longer being published in the Windows Phone Store. So far, there's no word on why the app has been pulled from circulation.