SPC Jun 30, 2020 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
Day 1 Outlook Image

Day 1 Convective Outlook NWS Storm Prediction Center Norman OK
1243 AM CDT Tue Jun 30 2020 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY...
Thunderstorms associated with large hail and wind damage will be
possible this afternoon through tonight across parts of eastern
Nebraska, the Dakotas and western Minnesota. ...Northern and Central Plains/Upper-Mississippi and Mid Missouri
Valleys...
A negatively tilted upper-level trough will move northeastward
across the central and northern Rockies today and into the northern
High Plains this evening. Ahead of the trough, a cold front will
advance eastward across the central and northern Plains. By
afternoon, the front is forecast to be located from western North
Dakota into central South Dakota and central Nebraska. The front
will provide a focus for convective initiation. Thunderstorms are
expected to first develop in the late afternoon from southern North
Dakota into central South Dakota with a north-to-south line quickly
forming by early evening. It appears likely that a linear MCS will
develop and move eastward across northeastern Nebraska and the
eastern Dakotas during the early to mid evening. Ahead of the cold front, a very moist airmass will be in place with
surface dewpoints in the lower to mid 70s F. In response, strong to
extreme instability should develop by afternoon with MLCAPE reaching
the 3500 to 5000 J/kg range. Convection will most likely form near
the front on the edge of the stronger instability where deep-layer
shear will be stronger than further east. RAP forecast soundings
near the front in the Dakotas at 00Z/Wednesday show 0-6 km shear
generally in the 25 to 35 kt range. This will support a severe
threat with the stronger cells embedded in the developing linear
MCS. Isolated large hail could occur with supercells early on. But a
rapid transition to linear mode should make wind damage a greater
threat. The wind-damage and hail threat should move eastward into
western Minnesota and northwest Iowa by late evening. ...Mid Mississippi and Tennessee Valleys/Southern
Appalachians/Carolinas...
West to northwest mid-level flow will exist today from the mid
Mississippi Valley to the Carolinas. At the surface, a moist airmass
will be in place across much of the southeastern U.S with surface
dewpoints ranging from the mid 70s F in the Tennessee Valley to the
upper 60s F in the southern Appalachians. In response, moderate to
strong instability will develop by mid afternoon across much of the
region. Scattered thunderstorms appear most likely to develop during
the mid to late afternoon along a gradient of instability from
southern Illinois southeastward into the southern Appalachians.
Convection should also form along pre-existing outflow boundaries.
As low-level lapse rates become steep, marginally severe wind gusts
will be possible with the stronger multicells or pulse storms. ..Broyles/Bentley.. 06/30/2020 

Read more

Be the first to comment on "SPC Jun 30, 2020 0600 UTC Day 1 Convective Outlook"

Leave a comment

Your email address will not be published.


*