EWP STATUS FOR 9 MAY 2013: 12 – 8 PM SHIFT

For Thursday, we are focusing on Texas and Oklahoma for severe potential.  An upper-level shortwave trough (associated with yesterday’s severe weather) will slowly progress east.   Associated severe parameters will shift south and east, toward the I-35 corridor.  Moisture quality should be higher than Wednesday’s event, given continued advection.   As a result, moderate to strong instability should develop from central Texas to central Oklahoma.  Additionally, deep-layer shear is forecast to range from 35 – 50 kts, which – given the forecast instability – should be more than sufficient for supercells.  Damaging winds and large hail should be the main threats, given weak low-level shear.  However, a few tornadoes cannot be ruled out.

In terms of timing, expect that severe thunderstorms will develop rather early, given the weak capping inversion.   The lift associated with the upper-level shortwave trough will be present early in the day, so storms may be ongoing at the beginning of operations.  Moreover, as the shortwave exits through the day, low-level winds will become more veered, reducing wind shear with time.  Thus, an earlier shift seems reasonable, so will go with the 12 – 8 p.m. for operations.

WFOs Likely to See Operations: Norman and Fort Worth

-G. Garfield, Week 1 Coordinator