Pacific Cyclone

I measured 0.9 inches of rain in Monterey, CA over yesterday evening and night. We also received hail that was the most clear hailstones I have ever seen. It was a very exciting rain storm. The power went out for about 20 seconds.

The HRRR analysis at 0000 UTC and 0400 UTC (4:00 PM and 8:00 PM Pacific Time) shows the cyclone approaching northern California.

This is the GOES-West satellite image at 0011 UTC on November 27th.

Quarter-Sized Hail

Quarter-sized hail was observed in this quick-moving thunderstorm that moved across the Salt Lake Valley before noon...

Radar 10:45 AM

Camera 10:55 AM

GOES-16 True Color Image and Lightning data 10:43 AM

It looks to me that the lightning data is skewed a little south of there it actually occurred. The center of maximum reflectivity is in the heart of Salt Lake County, but the lightning mapper positioned the flashes along the Salt Lake-Utah county line.

Rain and Hail in Spanish Fork

It's raining and hailing in Spanish Fork...

Time: 18:50 UTC

You can see the cooler air accompanied by the storm from the temperature and dew point time series...Temperature goes down, and wet bulb (humidity) goes up. When the temperature and dew point temperature are the same that is about all the cooling that can be done by evaporation...a natural air conditioner.

There is some good cloud development shown up in the satellite images...

Time: 18:56 UTC
weather.cod.edu

One interesting aspect of this storm is how the HRRR model handles it. The latest analysis hour has the reflective in the right spot, but the HRRR model gets rid of the storm by the first forecast hour. The storm has lasted into that hour, and so this is a case that the HRRR model is not useful for a short term forecast of this storm.

Time: 17:00 UTC

 Now look at the one hour forecast...the hail storm has disappeared. Yep, not really a useful short-term forecast.

Time: One hour forecast valid at 18:00 UTC

Quick Hail Storm

Quick and heavy hail storm in Salt Lake just moments ago...

The crane on campus switched directions, a sure sign that the gust front just passed

And down came the hail!

Rain --> Sun

Temperatures this month have been slightly cooler than usual, but not much. There has been more rain than your typical May. About half the days this month measuring rain at the airport. The amount of rain is about twice the normal amount for May.

Source: weather.gov/slc

Even right now there are severe thunderstorms passing through Box Elder county.

This weekend May will leave us warm and hot. Temperatures in northern Utah will be in the 80s. Take a look for yourself...this is the ridge forecasted to build over Utah on Sunday...

This is the NAM forecast for Sunday at noon. Perhaps it will be followed by a cool down when the trough over the ocean progresses inland.

Update: this morning I saw on twitter a few cool pictures from this storm. First, a picture taken Morgan County taken by Nicole McMillian.

And here's a look at quarterz sized hail out in the Uintah Basin!