Archive for April, 2008

Forecast for April 9, 2008

April 8, 2008

Forecast Made: April 8, 2008 – 20Z

Target: Roby, TX

Initiation Time: Showers/non-severe thunderstorms will likely be ongoing across the area Wednesday morning in advance of the warm front. Severe weather becomes more likely between 20-23Z near target area.

Discussion: The big question 36 hours out is how models are resolving a warm front that will move northward across west central Texas during the morning/early afternoon hours on Wednesday. Models have been in better agreement in recent runs that the front will be near the I-20 corridor by 12Z Wednesday. However, early morning drizzle/showers north of this front may slow the progression northward during the morning hours. Both the NAM and GFS are in reasonable agreement that a well defined triple point will set up early Wednesday afternoon near or just south of the Lubbock area. Initial storms should develop along this dryline by mid-afternoon. Primary threats initially with these supercells will include large hail, and possible some gusty winds. The tornado threat along/near the warm front will increase by about 0Z Thursday, as all models indicate 60 degree plus dewpoints pooling along the warm front. In addition, 0-3 km storm-relative helicity values ~500 m^2/s^-2 suggest that a couple of strong tornadoes may form after 0Z north of the Abilene area. Eventual loss of daytime heating will likely be overcome by stronger dynamics entering west Texas. Therefore, initial discrete storms should form a severe MCS by late Wednesday evening / overnight into Thursday for OK/north TX. Another potential target area during the day is near Childress, TX, but uncertainty with respect to strength/movement of the warm front in the area precludes mentioning a tornadic threat at the current time.

Conclusion: Impressive dynamics and moderate instability suggest supercellular storms will occur across parts of Texas on Wednesday. I like the area around Roby, TX / Abilene, TX tomorrow afternoon and evening.