U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 010530 
Storm Prediction Center ac 010529 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1229 am CDT Friday Aug 01 2014 

Valid 021200z - 031200z 

..no severe thunderstorm areas forecast... 

scattered thunderstorms should form along a frontal zone as it sags 
southeast across the eastern Dakotas and Minnesota. Gusty winds and 
perhaps some hail may accompany this activity. Elsewhere...isolated 
to scattered thunderstorms will develop across much of the interior 
west...especially across the lower Colorado River valley. 
Thunderstorms will also be common across the Gulf Coast into the 
middle Atlantic. 

..north central u... 

Northern-stream short-wave trough will dig southeastward across mb into northwestern 
Ontario by 03/00z which should force a weak cold front into central 
Minnesota...southwestward into eastern South Dakota. Although primary forcing will remain north 
of the international border...strong heating along the wind shift 
will allow surface temperatures to warm into the middle 80s-near 
90f...adequate for surface parcels to reach their convective 
temperatures. Forecast soundings for this region suggest weakly 
rotating updrafts could evolve as modest deep layer shear...veering 
with height...will exist for thunderstorms that manage to develop. Latest 
thinking is scattered convection should evolve by 00z then drift southeastward 
during the evening hours. Steep low-level lapse rates may 
contribute to gusty downdrafts and marginally severe hail could also 
be noted. Loss of daytime heating should result in weakening 

..lower Colorado River valley... 

Early morning WV imagery suggests a weak middle-level circulation over 
the lower Baja California peninsula. This feature is expected to drift north 
over the next few days and possibly deepen toward the end of the 
period over Southern California. Latest NAM depicts modest middle-level flow along 
the eastern semi Circle of this feature by the latter half of the day2 
period...though forecast thermodynamic profiles exhibit weak 
buoyancy due to very moist mid-levels. If boundary-layer heating is 
more substantial than currently forecast then sufficient instability 
may exist across this region for organized strong convection. Given 
the uncertainty in instability will not introduce severe 
probs...however robust thunderstorms may ultimately develop across this 
region Saturday. 


Scattered...primarily diurnally-driven convection is expected across 
much of the Gulf Coast into the middle Atlantic during the day2 
period. Weak large-scale forcing ahead of long-wave trough should 
aid thunderstorm coverage. Forecast instability/shear do not appear 
sufficient to warrant 5 percent severe probs at this time. 

.Darrow.. 08/01/2014