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.

Hurricane Matthew: Buckets of Rain

Fayetteville, North Carolina, recorded nearly 15 inches of accumulated rain in a 24 hour hour period on October 8th. This large rain event was due to heavy rain from Hurricane Matthew. Below is the radar at 1620 UTC.

Volunteer weather rangers from the CoCoRaHS network shows the high rain totals in North Carolina, especially Cumberland County.

My dad was on a trip in North Carolina, and his plane home was canceled because of the hurricane.

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

Spring Downpour and Waiting for a Train

FrontRunner trains were delayed yesterday afternoon. There were lots of people waiting in the rain at Murray Station.

Finally, the train came. Standing room only.

Murray Station at the red star

The storm was moving southeast. While skies to the east were dark, the skies in the near west were clear and sunny! This neat picture of the hospital shows the sunny reflection in the windows with the dark skies in the background.

The Mountain Meteorology Lab camera captured a nice rainbow.

Thunder and morning clouds

Last night was the first time in a long time when lightning woke me up in the middle of the night. Around 4:30 AM my dark bedroom flashed with light, followed by a loud crack from outside. I ran upstairs to watch the storm pass. It rained for about 30 minuets.

Radar image at 4:45 AM local time

Rain accumulation at my station in Spanish Fork. Rain started around 4:40 and ended around 5:00 Am

The storm has since moved north. My sister and mom shared this picture with me of the clouds in the morning looking west.

I'm leaving work late.

It's raining, and I really don't want to wait at the bus stop in the rain. Hopefully it will pass in an hour. I'm sure I'll hear from my Provo about the crazy rain they are getting right now.

Summer Thunderstorms

Yesterday's cooler temperatures were welcomed by many. Over the last five days in Spanish Fork we've been in the upper 90s but yesterday we cooled to the upper 80s as a daily high.

It was fun to see the some thunderstorms yesterday. I was outside watching the approaching lightning storm while waiting for the train. The rain drops were really large, and I got on the train just before it started to downpour!

CoCoRaHS show 082 inches of rain on the west side of the valley. I imagine this rain fell over a short period of time.

Last weekend I was up in the Sawtooth mountains and our first night we were treated with a good thunderstorm. Here's the video...

On the way home there was a lot of convection in central Idaho.

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!

Spring Storms

The SLC radar was active all day.

A professor at the U pointed out that Thursday morning's temperature profile follows the saturation adiabat throughout most of the troposphere. Very neat to see this...

Source: http://weather.uwyo.edu/upperair/sounding.html

Rain Droplet Growth: Collision-Coalescence Efficiency

When rain drops grow by collision and coalescence not every drop of water it hits gets absorbed by the bigger droplet. We therefore need to include an efficiency term in our equation of droplet growth.

Equation for the change in droplet radius over time. E represents the collection/coalescence efficiency. v_T is the terminal velocity of the drop, LWC is the liquid water content of the cloud, and ro (the funny looking p) is the density of water. We can integrate and solve this equation to determine the length of time required for a droplet to grow to some determined size.

Below is a video by Reid Wiseman, an astronaut at the International Space Station, demonstrating the collection efficiency of a raindrop.