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I'm sure they have, but I've also been drenched while reading a weather report that refused to admit it was raining in my city right now. It just told me it was

I'm sure they have, but I've also been drenched while reading a weather report that refused to admit it was raining in my city right now. It just told me it was cloudy, despite clear and rather heavy rain for 30+ mins straight over the whole city. To this day I haven't figured out how that's even possible.

n_plus_1_acc 3y ago
Depending in which sources they used, they simply interpolate on a very rough grid
- dataflow 3y ago
  I mean, I guess, but how rough of a grid are we talking? This wasn't a tiny city or something... it was a pretty populated city spanning a few miles across in a very populated and well known region. Granted I didn't walk around to check the whole city for rain, but the sky didn't make it look like the clouds were only above my head...
  - InSteady 3y ago
    microbursts are a thing. It's entirely possible much of your city was dry despite the cloud cover. Also possible they just done goofed.
  - n_plus_1_acc 3y ago
    O heard it can be as mich as 50 miles if they cheapskate hard
NordSteve 3y ago
One factor is your distance from the nearest weather radar, and nearest airport with automated weather observation. This sort of prediction is heavily dependent on whether the precip is detected by sensing. I've seen similar things in our area (Minnesota) where you drive through a snowstorm, but the radar shows nothing in theare.
- cogman10 3y ago
  I've seen variations in weather literally 10 miles apart. With torrential rain at work and nothing at home. I can't see how any weather predictor could be correct in that situation.
  - importantbrian 3y ago
    Living in Florida I've driven down the road and had it be raining on one side of the road and not raining on the other while the sun is shining.
- Fomite 3y ago
  Yeah. There's a place nearby where I live that's used for a lot of outdoor recreation like fishing and rafting, and the two weather stations that serve that area are a long way away.
bumby 3y ago
Was it saying there was 0% chance of rain or did it just not update to 100% even though you were experiencing rain? The latter is somewhat common because the models (AFAIK) use probabilistic estimates, where different initial conditions generate potentially distant outcomes. The number of “rainy outcomes” defines the probability of rain, and doesn’t necessarily get updated with real conditions.
hazbot 3y ago
This is probably because of either poor sensor coverage, or a stale (old) forecast. Many weather services do not issue 'nowcasts' that constantly update with the latest weather observations (it's a hard and interesting problem), but rather a single forecast say 4x a day as the latest Numerical Weather Prediction model run comes in. Fwiw, I agree with your bemusement and scorn - it's not good enough! (I say this as someone who has had roles where I issued these 'always stale' forecasts)

n_plus_1_acc 3y ago

Depending in which sources they used, they simply interpolate on a very rough grid

dataflow 3y ago
I mean, I guess, but how rough of a grid are we talking? This wasn't a tiny city or something... it was a pretty populated city spanning a few miles across in a very populated and well known region. Granted I didn't walk around to check the whole city for rain, but the sky didn't make it look like the clouds were only above my head...
- InSteady 3y ago
  microbursts are a thing. It's entirely possible much of your city was dry despite the cloud cover. Also possible they just done goofed.
- n_plus_1_acc 3y ago
  O heard it can be as mich as 50 miles if they cheapskate hard

NordSteve 3y ago

One factor is your distance from the nearest weather radar, and nearest airport with automated weather observation. This sort of prediction is heavily dependent on whether the precip is detected by sensing. I've seen similar things in our area (Minnesota) where you drive through a snowstorm, but the radar shows nothing in theare.

cogman10 3y ago
I've seen variations in weather literally 10 miles apart. With torrential rain at work and nothing at home. I can't see how any weather predictor could be correct in that situation.
- importantbrian 3y ago
  Living in Florida I've driven down the road and had it be raining on one side of the road and not raining on the other while the sun is shining.
Fomite 3y ago
Yeah. There's a place nearby where I live that's used for a lot of outdoor recreation like fishing and rafting, and the two weather stations that serve that area are a long way away.

bumby 3y ago

Was it saying there was 0% chance of rain or did it just not update to 100% even though you were experiencing rain? The latter is somewhat common because the models (AFAIK) use probabilistic estimates, where different initial conditions generate potentially distant outcomes. The number of “rainy outcomes” defines the probability of rain, and doesn’t necessarily get updated with real conditions.

hazbot 3y ago

This is probably because of either poor sensor coverage, or a stale (old) forecast. Many weather services do not issue 'nowcasts' that constantly update with the latest weather observations (it's a hard and interesting problem), but rather a single forecast say 4x a day as the latest Numerical Weather Prediction model run comes in. Fwiw, I agree with your bemusement and scorn - it's not good enough! (I say this as someone who has had roles where I issued these 'always stale' forecasts)