Where do you position yourself relative to a storm?
This question has a complex answer, so I will answer relative to my chase style:
- Early in the day (usually 10 a.m.-1 p.m.) I try to drive
to the area where the storms will occur, keeping 60-100 miles ahead of the
expected are of formation. I use the online models at the Storm Prediction Center (SPC) and University Center for Atmospheric Resrearch (UCAR),
plus SPC mesoscale discussions to figure where to go. When I stop for lunch,
I eat where I can scout the sky for forming cumulonimbus (Cb) clouds in the
- Based on my initial assessment of where the Cb indicate
the most energy, I relocate in fron of the forming storms, always keeping
mind my road options for several hours later. The key moment is when
I choose which storm to follow. I am within an hour's drive (40-60 miles)
of storms by now.
- I reposition so the storm moves more or less from left
to right in my field of view. The key in this stage is identifying features
of the storm, like the precipitation core ("core"), flanking line, gust front (if one
is present), etc. Storms change direction, so these features are critical
for gauging the safety of my position. See the idealized supercell graphic to see where these features might be seen. If the storm is moving from southwest
to northeast, I am south or southeast of the core.
WEBMASTER: Lisa Beal, firstname.lastname@example.org