Day 1 Outlook Day 2 Outlook Day 3 Outlook Days 4-8 Outlook

Day 1 Outlook Convective Tornado
Hail Wind
Categorical Day1 0100Z Outlook
Images courtesy of the NWS Storm Prediction Center
 Forecast Discussion

ACUS01 KWNS 130100
SPC AC 130059

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0759 PM CDT Sat Jun 12 2021

Valid 130100Z - 131200Z


Isolated significant severe wind and hail are possible this evening
across parts of the southern High Plains. Marginally severe wind
gusts will also be possible in parts of the lower Ohio Valley and

...Southern High Plains...
An upper-level ridge is located from the southern Rockies into the
central Plains. Beneath the ridge, a moist airmass is in place
across much of the southern High Plains. A strong west-to-east
gradient of low-level moisture is located across eastern New Mexico
and west Texas. Surface dewpoints along this gradient are mostly in
the 60s F, with the RAP analyzing MLCAPE generally in the 3500 to
4500 J/Kg range. Two clusters of strong to severe thunderstorms are
ongoing. The first is in southeast Colorado and the second is in
northeast New Mexico. These clusters are expected to move
east-southeastward along the corridor of moderate to strong
instability this evening.

Forecast soundings at 03Z this evening across far northeast New
Mexico into the western Texas Panhandle have directional shear in
the low-levels with west-northwesterly mid-level flow. This is
contributing to 0-6 km shear in the 30 to 35 kt range. The moderate
deep-layer shear combined with mid-level lapse rates near 8.0 C/km
should be favorable for supercells with large hail. The more
dominant supercells may be able to produced hailstones greater than
2 inches in diameter. As low-level flow strengthens this evening and
the two clusters move east-southeastward, cold pool development will
be possible. Wind damage will be likely along the leading edge of
any line segment that can become organized. Wind gusts over 65 knots
will be possible.

...Lower Ohio Valley...
The latest water vapor imagery shows a shortwave ridge located over
the lower Great Lakes. A cluster of strong to severe thunderstorms
is ongoing just to the west of the shortwave ridge from
south-central Illinois into north-central Indiana. The storms are
located on the northeastern end of a corridor of moderate
instability. The RAP is estimating MLCAPE across south-central
Illinois and western Indiana in the 2500 to 3500 J/kg range. This
combined with steep low-level lapse rates will be sufficient for
marginally severe wind gusts with the stronger multicells early this

A very moist airmass is in place across much of the southeastern
United States. Scattered thunderstorms are ongoing in this moist
airmass, mainly across west-central Alabama and eastern Georgia. In
addition to surface dewpoints in the lower to mid 70s F, the RAP is
estimating MLCAPE from 2500 to 3500 J/kg. This combined with steep
low-level lapse rates will be sufficient for marginally severe wind
gusts for another hour or two mainly in areas where convection is
already ongoing.

..Broyles.. 06/13/2021