Day 1 Convective Outlook AMEND 1
NWS Storm Prediction Center Norman OK
0503 PM CDT Thu Jun 22 2023

Valid 222000Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE CENTRAL AND SOUTH-CENTRAL HIGH PLAINS...WEST-CENTRAL AND
SOUTHWEST OKLAHOMA...

AMENDED FOR ENLARGING THE SLIGHT RISK ACROSS OKLAHOMA

...SUMMARY...
Widely scattered severe thunderstorms are forecast mainly this
afternoon into the evening across parts of the central and southern
High Plains, with a threat of large hail (possibly in excess of 2
inches in diameter), severe wind gusts, and a tornado or two.

...Updated Discussion...
Confidence has increased in a severe thunderstorm complex moving
east-southeastward across western and southwestern OK this evening. 
Have enlarged the 15-percent and 5-percent severe wind probabilities
to account for this.  Have also introduced a 15-percent hail
probability in southwest OK.

...Previous Discussion...
The only changes to the previous convective outlook include the
following:
1) Removed 15-percent wind probabilities over eastern NC into far
southeast VA due mostly to convective overturning and storm
weakening.  
2) Added a small 15-percent wind probability over west-central OK
and the far eastern part of the TX Panhandle.  A long-lived
thunderstorm complex will continue to move southeast this afternoon
into the eastern TX Panhandle and western OK.  The airmass to the
southeast is moderately unstable with 2000-2500 J/kg MLCAPE. 
Moderate west-northwesterly flow will aid in some storm organization
and widely scattered severe gusts are possible with this
thunderstorm cluster this afternoon into west-central OK.
3) Reduced wind and tornado probabilities in wake of the
south-southwesterly moving outflow boundary over northeast NM and
adjacent parts of the TX Panhandle.  Relatively cool/stable
conditions will likely limit the wind/tornado risk over the
northwest part of the TX Panhandle and far northeast NM.

..Smith.. 06/22/2023

.PREV DISCUSSION... /ISSUED 1109 AM CDT Thu Jun 22 2023/

...Northeast CO/Southeast WY/Southwest NE...
Another active day of strong/severe storms appears likely for
portions of the central High Plains.  Water vapor imagery shows a
band of moderately strong southwesterly flow aloft extending from
the southwest states into the central/northern plains.  Multiple
weak perturbations are embedded in this flow, and will likely
promote scattered thunderstorms off the high terrain by early
afternoon.  Boundary-layer moisture has lessened compared to
yesterday, but remains high enough to yield afternoon MLCAPE values
over 2000 J/kg.  Bulk shear will promote supercell storm structures
capable of large to very large hail and perhaps a tornado or two. 
These storms will spread across northeast CO and southeast WY during
the afternoon, with various morning CAM solutions suggesting
propagation into southwest NE/northwest KS tonight.

...Southeast CO/Northeast NM/Western TX Panhandle...
An ongoing MCS is building southward into the OK/TX Panhandles.  The
evolution of this system is unclear, but it should result in an
outflow boundary that extends westward into NM that aids
re-development of storms later today.  Supercell storms are
expected, capable of very large hail, damaging wind gusts, and a
tornado or two.  There is low confidence regarding the
evening/overnight evolution of these storms.  While several CAM
solutions bring the activity southeastward into central TX
overnight, the synoptic-scale low-level jet remains farther west,
suggesting that scenario is unlikely or will be primarily
non-severe.  Therefore will maintain only a broad MRGL risk across
much of TX.

...Northeast NC/Southeast VA...
A linear MCS will track northeastward across parts of eastern NC and
southeast VA today.  Skies have cleared ahead of the line, where
high dewpoints values will result in an area of moderate CAPE. 
Given the sufficiently strong low and mid level wind fields, have
added a small SLGT for this area.  Please see MCD #1205 for further
details.