AppStorm

AppStorm tells you, at a glance, the chance of a storm today and tomorrow where you are, at what time, and in which direction each storm is heading. Open the app and you'll see it in color, with a number and a word.

WHAT YOU'LL SEE
• The chance of a storm for today and tomorrow, from green to purple, and the hourly chance of thunder.

• A map with satellite cloud cover, lightning from the last 40 minutes, and the estimated path of each storm (this may change if the wind shifts).

• Hail: one, two, or three small hailstones will appear when a nearby storm has conditions for hail. This is an unverified warning: hail may not occur.

• The snowfall observed by the satellite in the mountains in recent days, and the snowfall predicted for your location, as a data point.

• Official alerts from the National Weather Service.

• Hourly and weekly temperature, wind, rainfall, and humidity.

PROFILES
A button changes the information below, always with the storm first:
• Hydro: Soil moisture (surface and deep) for the past week and what's coming, daily rainfall and the forecast for the next 3, 24, and 72 hours.

• Fishing: Wind, gusts, rainfall, temperature, and pressure.

• Paragliding: Surface and upper-level winds, and cloud base.

• Rural: Wind, rainfall, temperature, humidity, and Delta T. These are just data: there are no scores or recommendations.

CLIMATE
Up-to-date El Niño and La Niña, and how your location is today compared to the same date in typical years: how much colder or warmer, wetter or drier, how much rain in the last month, and the wind. And how frequent storms are month by month.

HOW IT WAS TESTED
The daily chance was tested against actual events at 44 stations across the country (July 2025 to September 2026), using forecasts stored before each day. In this test, 12 out of every 100 storms arrived with a "very low" chance, and 37 out of every 100 days with a high or very high chance had no thunder at the station.
The hourly chance improves by 0.11% above the normal for each location and time, but it overestimates in summer: thunder occurs 85 out of every 100 times the predicted time. The hour is approximate: on 4 out of every 10 days with a storm, thunder occurred at that exact hour.
The trajectories: the arrow's direction accurately reflects the expected direction; at 30 minutes, the position shifts by about 12 km. Beyond half an hour, it is not tested.
Hail, snow, profiles, and comparisons with El Niño and La Niña are not verified. Where something is unverified, the app will tell you.

NOT AN ALERT
Official alerts are issued by the National Meteorological Service (SMN). AppStorm is a complementary resource and does not replace it. In case of danger, follow official instructions. AppStorm is not affiliated with the SMN or any other government agency.

SIMPLE AND UNCOMFORTABLE
• No accounts required: it doesn't ask for your name, email, or phone number.

• No ads and no tracking.

• It only uses your approximate location (or the place you tap on the map); your exact location never leaves your phone.

• It doesn't run in the background or send notifications.

SOURCES
Open-Meteo (CC BY 4.0) and Copernicus ERA5 reanalysis, National Meteorological Service, NASA GIBS and NOAA (GOES-19 and VIIRS satellites, El Niño index), National Geographic Institute, and OpenStreetMap. Details and licenses are available within the app.

Made by Agustín Sigal (PhD in Physics, FAMAF-UNC), for non-commercial purposes.