U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 221807 
Storm Prediction Center ac 221807 

Day 2 convective outlook corr 1 
National Weather Service Storm Prediction Center Norman OK 
0107 PM CDT Wed may 22 2019 

Valid 231200z - 241200z 

..there is an enhanced risk of severe thunderstorms across the Ohio 
Valley/middle Atlantic and southern/Central Plains... 

Corrected for missing thunder line 

Severe storms with large hail, damaging wind and tornadoes will be 
possible over a part of the central and Southern Plains Thursday. 
Other severe storms with a threat for mainly damaging wind and large 
hail are expected from a portion of the Ohio Valley into the 
northern middle Atlantic. 

..upper Ohio Valley/northern middle Atlantic... 

Central US short-wave trough is forecast to eject northeast across 
the Great Lakes and flatten the eastern ridge as 80kt 500mb speed 
Max translates across Lake Erie. This feature is expected to aid 
early-morning convection across the Ohio Valley which will propagate 
into eastern Ohio/western PA by 18z. Depending on the evolution of 
this convection it appears environmental shear will become favorable 
for sustaining fast-moving organized updrafts. Latest model guidance 
suggests upward-evolving thunderstorms by early afternoon within 
strengthening westerly flow regime. Boundary-layer heating is 
expected to be maximized from south-central PA, south along the Lee 
of the central Appalachians. If a cold pool develops early, severe 
thunderstorms should initiate along the 
eastern-southern-southwestern flank of this activity then 
spread/develop east-southeast toward the Delmarva. Several cams 
solutions support this scenario and will extend higher severe probs 
into northern Maryland to account for the more southeast propagational 
component. Damaging winds, and some hail, are expected with 
convection as it spreads across eastern Ohio/PA toward northern Maryland by 
late afternoon. 

..central/Southern Plains... 

Strong mid-level flow is forecast to round the base of western US 
trough over northern Mexico late day1 into early day2, then 
translate into the Central High plains by 24/00z. In response to 
this feature, low level jet should strengthen across the Texas South Plains late 
Wednesday. This will allow for a substantial moisture surge to at 
least 102w longitude where higher terrain and heating along the 
western edge of this moist plume should contribute to robust 
convection. There is some concern that convection could develop 
early in the period along the nose of the low level jet. This activity is most 
likely across the northern Texas Panhandle into western Kansas atop cooler 
boundary air mass that will sag south across the High Plains. This 
early-day convection will likely be elevated and pose primarily a 
large hail threat. However, strong surface heating near the nm/Texas 
border will contribute to substantial buoyancy that will become 
uncapped by late afternoon. Forecast shear profiles strongly favor 
supercells and a fair number of storms should ultimately evolve 
across the enh risk. High-precipitable water air mass should surge into this region 
such that long-lived supercells are expected. Very large hail and 
tornadoes can be expected with supercells south of the cold front 
that will Orient itself across southwest-central Kansas. If early-day 
convection is less than currently expected, a corridor of higher 
severe probs may ultimately need to be considered across the High 
Plains south of the front. 

..maximum risk by hazard... 
Tornado: 10% - enhanced 
wind: 30% - enhanced 
hail: 30% sig - enhanced 

.Darrow.. 05/22/2019