Showing posts with label ensemble forecast. Show all posts
Showing posts with label ensemble forecast. Show all posts

Friday, March 25, 2016

NCAR Ensembles

Found a new webpage that show NCAR ensembles, and these weather maps look really clean! These are useful for forecasting when you get up in the morning and want a nice review of the day ahead of you :)

The NCAR ensemble is a 10 member ensemble run at 3-km horizontal resolution initialized once a day at 0000 UTC and run for two days.

Here's the maps for the southwest 2-m mean temperatures, sea level pressure, and 10-m wind:  http://ensemble.ucar.edu/images.php?d=2016032500&f=t2_mean&r=SW&i=1
(note: you can toggle on/off the county lines by pressing [o])





Also interesting is seeing the data assimilation for the model. Here's a map showing the locations of the data used in the model.

The data assimilation is feed into another model to create a 15-km analysis of atmosphere every 6 hours which is used in the forecast model. You can look at analyses here: http://www.image.ucar.edu/wrfdart/rta/images.php?d=2016032500&f=t2_mean_f000_ANLYS&r=CONUS


Saturday, November 14, 2015

Snow Coming Sunday Night/Monday Morning

The storm is on its way. Sunday Night and Monday you'll see more snowflakes falling. It seems like the impact of winter storms are a distant memory to me, so prepare yourself for this season's first winter storm. It will likely have a big affect on your morning commute.

The NAM forecast below can be viewed at weather.utah.edu. This shows the approach of the pressure trough and the snow delivered to our mountains.

How much snow are we expecting?? We'll need to look at ensemble forecast to answer that question. Below shows the amount of snow expected in Salt Lake as forecasted by a dozen different models...
It's usually a pretty good guess to take the mean of the models -- about 2-3 inches of Snow on Monday -- But that's not to say the models predicting over 5 inches are totally out to lunch (though, I'm less inclined to believe it). I'll stick with the mean on this one.

Another way to look at these ensemble forecasts is by looking at a probability of different amounts of snow. Study the different plots below... The one on the top right suggests all of Salt Lake and Utah County have greater than 90% chance of receiving more than an inch of snow in the next week. Most of that snow will occur on Monday. Mostly the mountains and benches have a high chance of receiving more than 6 inches. And only the highest peaks have a high chance of getting a foot of snow.

It'll be important to keep an eye on this storm, especially if you are commuting into work or school Monday morning. You'll want to give yourself some extra time, or maybe go in late and wait for the roads to be cleared.