Severe Weather Discussion for April 3, 2008.
– Active severe weather day is likely for the southeastern 1/3rd of
Oklahoma, and much of eastern Texas. Primary threats are destructive
hail, isolated tornadoes, and damaging winds.
– Chase Status is raised to Level 4. We will be departing around
15:00 CDT, the chase cam will be online. Additionally, we'll be
blogging from the road. You can track us through APRS or Spotter
Network at http://www.spotternetwork.org, click National Activity.
Our target area is Lawton.
No change to reasoning from yesterday. SPC Day 1 is awesome, and it
is scary that we're all on the same page. Initial wave lifted north
of the region this morning and is veering the surface – 850mb flow.
Shortwave ridging is taking hold and this will suppress activity for a
few hours. These factors should assist low clouds in clearing,
allowing for strong diurnal heating in the threat area today.
CAPE values should be at least 2500J/Kg later today with LIs to -8.
Helicity will initially suffer due to veered surface flow. However,
the 06z and somewhat 12z NAM are more robust with a surface low
developing near Childress late this afternoon. This may serve to back
the surface flow and enhance 0-1km helicity across the region.
Storms should initiate between 4-6pm along the dryline, which is
expected to be near or just east of Altus. 700mb flow is around
30kts, so storms aren't going to move fast. Given week low level
flow, per SPC, splitting supercells are likely. Destructive hail is
likely with any left splits. Isolated tornadoes seem possible early
on in the event. By late evening, a linear system should develop as
the cold front over takes the warm sector. Texas will be in the
threat for a while longer.
GFS and ECWMF continue to hint at a longwave trof next week. GFS is
more progressive while the ECMWF is slower. Additionally, the GFS
lifts a larger part of the energy out at D7. No reason to pick either
one, but potential exists for a medium-end event. I'd like it to be
April 10th, but we'll see.
Level 4 – Heading to Lawton at 15:00 CDT.
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