Severe Weather Discussion for May 23, 2008.
– Severe thunderstorms are expected again late this afternoon and
evening across the western half of Oklahoma. Primary threats are
destructive hail, isolated tornadoes, and damaging winds.
– Isolated severe thunderstorms remain in the forecast through Monday.
Late morning surface analysis indicates dewpoints in the upper 60s to
low 70s with temperatures already near 80F. This is resulting in a
very unstable atmosphere, with SBCAPE 3000-4000 J/Kg and 100mb MLCAPE
2500-3000 J/Kg, all east of a dryline in the eastern Texas panhandle.
The dryline is expected to move a little more east and be near the
TX/OK border by mid-afternoon. Atmospheric wind profiles look
impressive for late May and will provide a favorable environment for
supercells. Unlike Thursday, deep layer moisture exists across the
The main question for this afternoon will be storm initiation as a
strong low level focus and midlevel lift are not present. However,
presence of a 700mb shortwave trof along with decent moisture
convergence near the dryline should be sufficient for isolated severe
thunderstorms to develop. The 12z NAM is rather robust on
precipitation and may develop too much. This is a dry bias model and
the amount of QPF generated is of interest. The 15z RUC also develops
QPF along the western border, so there seems to be increasing
confidence of at least a few severe thunderstorms in western Oklahoma
later today. Amount and degree of instability strongly points to hail
up to baseball size, along with isolated tornadoes and damaging winds.
The I-40 corridor is of particular interest to me given last night's
convection in this area. A differential heating boundary should setup
just south of the rainfall area. This could aid storms later today if
they can intersect and anchor in this area.
Slight risks near the area are a given the next few days, but appears
the significant will not be there to warrant discussions.
Level 1 – but might try to sneak out west later.
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