SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Jun 05 2022
Valid 052000Z - 061200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
OKLAHOMA/KANSAS AND WESTERN NEBRASKA...
...SUMMARY...
Significant severe thunderstorms producing very large hail, intense
damaging winds, and a few tornadoes remain possible across parts of
Nebraska, Kansas, and Oklahoma late this afternoon through tonight.
...20Z Update...
No changes have been made to the Enhanced Risk extending from parts
of NE across KS and into northern/central OK. A robust supercell
producing large hail has recently developed over north-central KS on
the eastern extent of persistent cloud cover in western KS. It
remains somewhat unclear when/where additional intense thunderstorms
will develop across northern/central KS this afternoon and evening.
There will be some potential for convective initiation later this
afternoon into the early evening along a dryline/outflow boundary
intersection in the southwestern KS to northwestern OK vicinity.
But, warm mid-level temperatures are still contributing to a
substantial cap across this area based on recent mesoanalysis
estimates.
Isolated to scattered thunderstorms appear more probable to develop
across parts of western into central NE, northwestern KS, and far
eastern CO along a surface trough in the next few hours as modest
upslope flow occurs and a weak mid-level disturbance ejects over the
central Plains. This may already be occurring across parts of
northwestern NE. Given the presence of steep mid-level lapse rates
and adequate deep-layer shear, very large hail will be a possibility
with any supercell that can be sustained. Otherwise, a southerly
low-level jet that is forecast to strengthen this evening and
tonight across the southern/central Plains should aid in upscale
growth of convection across parts of central/southern KS and perhaps
northern OK. Intense, severe wind gusts will be possible if this
evolution into a bowing MCS occurs. But, there is still substantial
uncertainty regarding the most favored corridor for this potentially
significant MCS.
Some expansion to the Marginal Risk has been made across parts of
central/eastern OR into eastern WA based on recent observational and
radar trends. Isolated hail and locally damaging winds remain
possible with any of the stronger cores that can develop across the
interior Pacific Northwest into the northern Rockies. See Mesoscale
Discussion 1038 for more details on the short-term severe threat
across this region.
..Gleason.. 06/05/2022
.PREV DISCUSSION... /ISSUED 1146 AM CDT Sun Jun 05 2022/
...Kansas/Nebraska/Oklahoma...
A semi-organized MCS continues southeastward at midday across
eastern/southeast Oklahoma. Episodic pulse-type severe cores may
persist on its western flank for a time this afternoon while it
otherwise spreads toward the Ozark Plateau and ArkLaTex vicinity.
Isolated severe hail on its western flank is the most probable risk,
but some diurnally renewed damaging wind potential is also plausible
downstream.
To the west of this MCS and near/west of its related outflow, a very
unstable environment will evolve this afternoon across the High
Plains including western Nebraska and western/southern Kansas into
Oklahoma. 12z upper-air data featured semi-cool mid-level thermal
profiles for early June as noted from Dodge City/North Platte
observed soundings with 500 mb temperatures around -12C to -13C,
although a notable capping inversion was noted to the southwest (12z
Amarillo sounding around 14C at 700 mb). Related High Plains
elevated mixed layer plume will persist and modestly advect/recover
eastward today on the western fringes of the late-night and early
morning MCS now over eastern Oklahoma. This will be atop mid/upper
60s F surface dewpoints, which will contribute to ample buoyancy
with upwards of 3000+ J/kg MLCAPE in the aforementioned corridor.
Storms are most likely to initially develop near the front across
Nebraska this afternoon, with deep convective initiation in/around
peak heating a bit more uncertain (but still very plausible) across
western/south-central Kansas and northwest Oklahoma in vicinity of
the outflow boundary and lee trough/dryline vicinity. Multiple
sub-regional corridors of several intense supercells can be expected
with initial development. This includes potential for very large
hail given the lapse rates/buoyancy reservoir and moderate
deep-layer shear, which will be accentuated by relatively strong
west/northwesterly high-level winds. A couple of tornadoes are
possible as well.
Consolidating cold pools will likely yield upscale growth into a
maturing MCS towards south-central Nebraska and central Kansas
during the evening. The overall intensity/coverage of the severe
wind threat with this MCS will be modulated by whether a separate
MCS will be simultaneously developing/ongoing in far southern Kansas
and northern Oklahoma. Although there are timing/spatial
uncertainties, aggregate meteorological scenario suggests a
relatively high net potential/probability of large hail and
widespread damaging winds this evening into the overnight across
parts of southern Kansas and Oklahoma.
A Moderate Risk upgrade could still be warranted later today pending
greater confidence in a confined corridor of intense storm
development including higher-end wind potential this evening into
the overnight.
...Interior Northwest/northern Great Basin...
Within the left exit region of an intense upper jet centered on
northern California and southern Oregon, scattered thunderstorms are
expected this afternoon from eastern Oregon across Idaho into a
portion of western Montana, and in a more isolated sense across
northern Nevada/Utah. Elongated, straight-line hodographs will
encourage a few splitting supercells. However, buoyancy will likely
remain weak with moderate mid-level lapse rates and below-normal
surface temperatures. This suggests that isolated severe hail will
be the primary hazard (especially across northern parts of the
region), with locally strong wind gusts also a viable risk.
Read more CHECK UPDATE ZOOM GRAPHIC
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