Severe Weather Discussion for April 6, 2010.
– Isolated severe thunderstorms are possible later today, primarily in
northeast Oklahoma. Primary threat is large hail, but an isolated
tornado cannot be ruled out.
– Severe thunderstorms are possible on Tuesday across central and
– Chase Readiness is increased to Level 2 for Tuesday.
No changes to prior thinking for today or tomorrow. Models continue
to indicate a warm front developing in northern Oklahoma later today
as 60F dewpoints pool to the south. Activity is expected to remain
limited and mostly confined to northeast Oklahoma. Large hail is the
primary threat, but an isolated/brief tornado cannot be ruled out.
Western U.S. trof approaches the region on Tuesday with thunderstorms
expected on the dryline. GFS and NAM continue to disagree on the
dryline position with about 100 miles difference between the two.
Much of this difference centers around how each models handle the lead
shortwave trof ejecting into Nebraska Tuesday afternoon. There is no
reason to pick one model over the other. The GFS was a better
performer on Friday's system than the NAM. Either way, the difference
in dryline position is not significant enough to keep from chasing.
The GFS would be very near OKC and the NAM farther west near
CAPE values just east of the dryline by 7pm Tuesday are around 1500
J/Kg, with slightly higher pockets in isolated areas. LIs are around
-5 to -6, so marginal instability will be present. Models don't show
much in the way of mid-level lift, but that may not be a bad thing.
While the cap will be strong, models consistently show it will be
breached late Tuesday afternoon. NAM shows good helicity across the
region. Primary limiting factor at this point appears to be marginal
moisture return and somewhat weak 850mb winds. However, given the
rather non-existent severe weather season, I'm not going to turn it
Risk area for any part of OK/TX (valid: 04/05 Day 2):
Level 2 – Watching Tuesday
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