3/28/98 Chase Summary by Jeff Wear


From: Jeff Wear (jwear@compuserve.com):

As expected, Saturday turned out to be another chase day here in the San
Joaquin Valley.....

Before I got in my car for an actual chase, I wanted to make absolutely
sure storms would miss the Turlock area. Lots of TCu and Cb built up all
over the place by late morning - one giving us a brief shower of 1/8
inch hail at 1332. But these started to fall apart around 1500, and the
remaining altostratus overcast killed Turlock's chances for storms.
However, the sun was still shining to the south in Merced County - and
TCu were rapidly building there. At 1600, I had my eyes on a cell in SE
Merced County that was starting to look very impressive on radar. I also
had my eyes on some cells just to the east of Turlock at the same time,
and wanted to see what these would do before I left for the cell in
Merced County. At 1630, these cells to my east began to gust out -
dropping the temp here in Turlock from 58F to 47F. I then heard that NWS
Hanford had just issued a severe t'storm warning for the storm in SE
Merced County - so I got in my car at 1700 and headed for this cell.

To get to this cell as quick as possible, I'd have to do some core
punching. Before the storms began to develop, temps had been in the mid-
50s to near 60 - while dewpoints were only in the 30s. With air this
dry, any rain that fell through it would dramatically cool the air
through evaporation - possibly all the way down to the dewpoint temp
itself. Knowing this, I expected that this storm might have a little
more than rain and hail in its core.

As I headed southbound on Hwy 99 out of Turlock, I began seeing frequent
cloud-to-cloud and cloud-to-ground lightning from cells just to the SW
and S of Atwater and Merced. Since the cores of these cells were SW and
S of the highway, I didn't encounter any hail with these - just mdt-hvy
rain in Atwater in Merced. Temps were quite chilly - 44F in Atwater and
41F in Merced.

Once SE of Merced, I started to encounter 1/4 inch (pea-sized) hail. It
looked to me that there had been even more hail just minutes before I
arrived - about 1/4 inch of hail was covering the ground. Just up the
road, I saw emergency vehicle lights flashing. When I got to the Lingard
Rd exit at 1730, I found out why. FOUR INCHES OF HAIL WAS COVERING THE
HIGHWAY!!!! There had been an accident (undoubtedly hail related) near
the Lingard Rd exit, and the ambulance was there to take away the
injured victim(s). Travel over the next six miles was very difficult -
that entire stretch of Hwy 99 was covered with 4-inch accumulations -
which looked more like snow than hail. Temp was only 37F - so I imagine
the hail was probably mixed with snow pellets - or maybe even flakes
themselves. Still, it was a very rare sight at only the 200-ft elevation.=


Once I got past the Sandy Mush Rd exit, roads were clear once again -
but the ground was still covered with 1/4 inch to 1 inch of pea-sized
hail. I continued south on Hwy 99 into Madera County into Chowchilla. In
Chowchilla, everything in sight was covered with about an inch or less
of pea-sized hail - the ground, rooftops, railroads, etc. There was even
a herd of sheep covered with hail - acting as if nothing had happened!
But by this time, darkness was beginning to set in - it was time to head
home. I didn't want to drive back to Turlock through the slushy
accumulations on Hwy 99 - so I took Hwy 233 to Hwy 152 and headed west
towards Los Banos.

Once in Los Banos at about 1825, I stopped at a gas station to call home
to check on things. As I hung up the phone, SNOW PELLETS began to fall.
Temp was just 41F - cold enough for the snow pellets to reach the ground
- just barely above the 100-ft elevation! I shot about a minute of video
of the snow pellets and the TCu and Cb surrounding Los Banos - then got
back in my car and headed home.

Another pool of cold mid-level air is gathering in the Gulf of Alaska
-looks like Tue/Wed could bring more wx excitement to the area....


Jeff


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