U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 160601 
Storm Prediction Center ac 160600 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0100 am CDT sun Jun 16 2019 

Valid 171200z - 181200z 

..there is a slight risk of severe thunderstorms across portions of 
the middle Atlantic... 

Isolated severe thunderstorms may occur across parts of the mid 
Atlantic into the Ohio/Tennessee valleys and mid Mississippi Valley 
on Monday. Other strong to severe storms will also be possible over 
portions of the southern/Central High plains. 

..mid Atlantic into the Ohio/Tennessee valleys and mid MS valley... 
A subtle vorticity maximum should be present over the Ohio Valley 
Monday morning, and will likely move eastward across portions of the 
mid-Atlantic through the day. A nearly stationary front should 
extend west-east across PA and vicinity. To the south of this 
boundary, strong diurnal heating is expected, with temperatures 
likely climbing into the upper 80s and 90s along/east of the Blue 
Ridge mountains. This heating coupled with a moist low-level airmass 
will support moderate to strong instability developing by early 
afternoon across much of the mid Atlantic. Ascent associated with 
the vorticity maximum should encourage initial convective 
development across the higher terrain of WV and western MD, 
subsequently moving eastward across northern VA, Maryland/DC, southern 
PA/NJ, and Delaware through the evening. Forecast soundings from the GFS 
and NAM show sufficient effective bulk shear (generally 30-40 kt) to 
support multicells and perhaps some marginal supercell structures. 
Damaging winds will probably become the main threat as storms 
attempt to grow upscale into a small bowing complex, although 
isolated large hail may occur initially as well. 

Another weak shortwave trough over MO/Arkansas at the beginning of the 
period should move northeastward across the Ohio Valley into confluent 
flow and slowly weaken. Still, a belt of modestly enhanced mid-level 
flow associated with this feature should overlie a moist warm sector 
that will be present to the south of a weak surface boundary. Weak 
to locally moderate instability coupled with marginal shear may 
support occasional updraft organization, with both a damaging wind 
and hail threat with any storms that form across from the mid MS 
valley into the Ohio/Tennessee valleys Monday afternoon and evening. 

..southern/Central High plains... 
Some increase in mid-level westerly flow should occur across parts 
of the southern High Plains by late Monday afternoon, and isolated 
to perhaps widely scattered storms may form along a surface dryline. 
Both low and mid-level lapse rates are forecast to steepen through 
the day across this region, with moderate to locally strong 
instability probable. There should be enough mid-level flow to 
provide some potential for storm organization as convection moves 
slowly eastward through early evening. Isolated instances of large 
hail may be noted with more cellular activity initially, with some 
increase in the strong to damaging wind threat with eastward extent. 
Generally modest shear magnitudes still suggest the overall threat 
remains somewhat marginal. 

Farther north, a northern-stream shortwave trough should move across 
the Dakotas on Monday, and storms may develop along a weak front 
from Minnesota/South Dakota into NE and eastern Colorado. Even though low-level moisture 
should remain limited, weak to locally moderate instability should 
develop by peak afternoon heating south of the front in combination 
with modest shear. There is enough signal in latest guidance for an 
isolated hail/wind threat with this activity to extend the marginal 
risk northward across parts of the Central High plains. 

..maximum risk by hazard... 
Tornado: 2% - marginal 
wind: 15% - slight 
hail: 15% - slight 

.Gleason.. 06/16/2019