jeffl
05-07-2005, 09:51 AM
Active more typical May period shaping up for the southern plains starting this evening.
Strong upper level trough over the W US will eject into the plains late today with a secondary vort max over NW Mexico currently swinging across TX tonight and Sunday. Low level moisture is increasing as surface pressures fall in the lee of the Rockies. Low to mid 60 degree dewpoints will spread inland into N TX and NW TX today with near 70 degree dewpoints along the coast by early Sunday (PWS rising to near 1.5-1.7 in).
Forecast models minus the dry GFS support thunderstorm develop tonight over central and SW TX into NW TX ahead of the dryline and ahead of the eastward moving short wave over NW Mexico. Models and SPC agree with upscale development into an MCS driven by favorable 250mb upper air venting, good low level inflow, and favorable low to mid level shear. 1000-500 mb thickness lines support a MCS track generally toward the E and ENE from SC TX through early Sunday morning.
Sunday:
MCS should be ongoing along I-35 Sunday morning. Air mass over E TX will be moist and unstable with CAPES forecast near 2500 J/kg, LI's near -6, and favorable low level shear. Diurnal heating effects suggest the MCS may weaken in the morning and then regenerate along and S of a well defined MVC by early afternoon. Location and track of MVC will be detrimental in convective evolution Sunday across SE and E TX. Additionally, since this will be a mesoscale driven event it is not out of the question that the MCS sweeps off the coast Sunday morning with no development Sunday evening. Future guidance this afternoon should help determine the extent and severity of the overnight thunderstorm complex and shed light on potential developments Sunday.
Main severe weather threats will be damaging winds and large hail.
Strong upper level trough over the W US will eject into the plains late today with a secondary vort max over NW Mexico currently swinging across TX tonight and Sunday. Low level moisture is increasing as surface pressures fall in the lee of the Rockies. Low to mid 60 degree dewpoints will spread inland into N TX and NW TX today with near 70 degree dewpoints along the coast by early Sunday (PWS rising to near 1.5-1.7 in).
Forecast models minus the dry GFS support thunderstorm develop tonight over central and SW TX into NW TX ahead of the dryline and ahead of the eastward moving short wave over NW Mexico. Models and SPC agree with upscale development into an MCS driven by favorable 250mb upper air venting, good low level inflow, and favorable low to mid level shear. 1000-500 mb thickness lines support a MCS track generally toward the E and ENE from SC TX through early Sunday morning.
Sunday:
MCS should be ongoing along I-35 Sunday morning. Air mass over E TX will be moist and unstable with CAPES forecast near 2500 J/kg, LI's near -6, and favorable low level shear. Diurnal heating effects suggest the MCS may weaken in the morning and then regenerate along and S of a well defined MVC by early afternoon. Location and track of MVC will be detrimental in convective evolution Sunday across SE and E TX. Additionally, since this will be a mesoscale driven event it is not out of the question that the MCS sweeps off the coast Sunday morning with no development Sunday evening. Future guidance this afternoon should help determine the extent and severity of the overnight thunderstorm complex and shed light on potential developments Sunday.
Main severe weather threats will be damaging winds and large hail.