LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Sat Aug 05 2023
Valid 051630Z - 061200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN
COLORADO INTO SOUTHERN KANSAS AND NORTHERN OKLAHOMA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN A SEPARATE AREA
FROM EASTERN ILLINOIS INTO CENTRAL AND SOUTHERN PARTS OF INDIANA...
...SUMMARY...
The most concentrated area of severe thunderstorms with potential
for destructive wind and hail is expected across parts of the
south-central Great Plains from mid-afternoon through tonight.
Potential for a few tornadoes will exist separately over the
Mid-Missouri and Wabash Valleys during the late afternoon to early
evening.
...Synopsis...
Water-vapor imagery this morning shows a rather complex upper-air
pattern with several important features that will influence the
severe threat this afternoon into tonight. An MCV located over the
southeast KS/northeast OK vicinity will continue to move east across
the Ozarks during the day. Another MCV over IL will gradually shift
east into IN by this evening. A mid-level low will move little over
SD during the period, while a belt of stronger mid- to upper-level
flow associated with an upper jet noses into the central High
Plains. In the low levels, extensive outflow is evident over much
of the northern half of OK into KS in wake of earlier morning
thunderstorm activity near the OK/KS border. Easterly low-level
flow will aid in maintaining moist conditions into eastern CO
southward to the Raton Mesa. A narrow moist plume will protrude
northward from eastern NE/western IA into southeast SD ahead of a
gradually eastward-moving cool front. Low-level confluence will aid
in focusing thunderstorm development over the lower Wabash Valley
beginning early this afternoon through early evening.
...Eastern CO/northeast NM into the TX Panhandle and KS/OK...
Not much change from previous forecast thinking. Convective outflow
late this morning arcs westward across central OK through the
central TX Panhandle. Near and north of the outflow, late morning
thunderstorms over OK may continue to linger into the mid afternoon
across the northern half of OK and pose an isolated risk for severe
gusts. The initial thunderstorm development and more appreciable
severe risk will probably focus near the Raton Mesa and Palmer
Divide towards mid-afternoon. Moist upslope flow beneath the left
exit region of an upper jet overspreading the central High Plains
will facilitate a favorable setup for supercells. Potential will
exist for regenerative supercells spreading east-southeast off the
higher terrain. A few of these may become long-lived and capable of
producing baseball to softball-sized hail centered on the southeast
CO vicinity given highly elongated mid to upper hodographs and large
buoyancy amid very steep mid-level lapse rates.
A strengthening low-level jet over west TX during the evening will
favor increasing convective development with multiple severe
thunderstorm clusters spreading across western and southern KS, the
Panhandles, and western to northern OK. Severe
wind gusts will become more prolific as this occurs, which should
include potential for sporadic gusts from 70-85 mph.
...Ozarks/Mid South...
Ongoing thunderstorm cluster late this morning will continue to move
east into a destabilizing and very unstable airmass across northern
AR. Strong heating via mostly clear skies will result in
temperatures warming into the 90s with mid to upper 70s dewpoints.
Forecast soundings show a moderate mid-level flow enhancement via
the approaching disturbance and MLCAPE 3000-4500 J/kg. Although
uncertainty is high regarding details, it is possible some
rejuvenation to the thunderstorm activity occurs on the periphery of
the deeper cores going forward into the early-mid afternoon. If
this occurs, widely scattered strong to severe gusts are possible
into the early evening.
...Mid-MO Valley vicinity...
A mid-level low over central SD will drift east with stronger
destabilization confined downstream of it from southeast SD to
eastern NE and far western IA. Early afternoon convective
development will initially be most pronounced across southeast SD
and likely arc southward into at least northeast NE before spreading
into northwest IA later. Weaknesses in the mid-level wind profile
may yield a linear cluster type mode, but some enlargement to the
low-level hodograph, especially in the SD/NE/IA border area, should
foster low-level updraft rotation capable of producing a couple
tornadoes. Otherwise, slow-moving linear clusters will yield a
threat for isolated severe hail and wind persisting through the
evening.
...IL/IN vicinity...
An MCV over central IL will drift east into IN through tonight.
Continued destabilization despite appreciable cloud cover will
become increasingly conducive for scattered storms to develop by
early to mid afternoon. Forecast soundings show a spatially
confined corridor of favorable low-level SRH overlapping the
northeast extent of the surface-based instability plume in southern
parts of IL/IN. A few supercells will probably evolve as storms
mature through the late afternoon/early evening and move east into
south-central IN. Any vigorous updraft/supercell will be capable of
at least an isolated, short-term risk for a tornado given the wind
profile/moist low levels.
..Smith/Squitieri.. 08/05/2023
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