SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0801 PM CDT Tue Apr 12 2022
Valid 130100Z - 131200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
IOWA AND FAR SOUTHERN MINNESOTA...
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...MID MISSOURI VALLEY AND MID TO UPPER
MISSISSIPPI VALLEY...
...SUMMARY...
Scattered severe thunderstorms capable of producing very large hail,
damaging winds, and tornadoes are expected late this evening and
tonight across a broad portion of the southern/central Plains into
the Mississippi Valley. Some of the tornadoes could be strong across
parts of Iowa.
...Central Plains/Mid To Upper Mississippi Valley...
The latest surface analysis shows a 987 mb low over western Iowa
with a cold front extending south-southwestward across the central
Plains. A moist airmass, with surface dewpoints in the lower 60s F,
is in place to the east of the front across much of Iowa, eastern
Kansas, Missouri and Illinois. Strong to severe thunderstorms,
discrete in nature, are ongoing along and to the north of a warm
front extending eastward from the low across northwest and
north-central Iowa. A narrow line of strong to severe thunderstorms
are just ahead of the cold front across eastern Nebraska and
northern Kansas.
In the mid-levels, water vapor imagery shows an upper-level low in
the northern High Plains. A plume of mid-level moisture extends
northeastward across the central Plains where a 60 to 75 knot
mid-level jet is located. As the jet moves northeastward across mid
Missouri Valley and mid to upper Mississippi Valley this evening, a
low-level jet will strengthen across the region. This will continue
to result in widespread severe thunderstorm development, with a
potential for large hail, wind damage and tornadoes. The tornado
threat will be greatest with supercells that interact with the warm
front this evening across northern Iowa. 0-3 km storm relative
helicity is forecast to remain in the 500 to 600 m2/s2 range near
the warm front suggesting that strong tornadoes will be possible
with supercells that remain dominant. These storms could also
produce wind damage and hailstones of greater than 2 inches in
diameter. To the north of the warm front, supercells with large hail
and strong wind gusts will also be possible from far eastern South
Dakota into southern Minnesota.
Further to the southwest, a line of strong to severe thunderstorms
will remain intact this evening, and expand southward across most of
eastern Kansas. Wind damage will be likely along the leading edge of
the line as it moves east-southeastward across the mid to lower
Missouri Valley this evening. A few wind gusts of greater than 65
knots along with large hail will be possible along the more intense
parts of the line. The severe threat will continue to develop
eastward into the Ozarks tonight, but should become more isolated
with time.
...Southern Plains/Lower Mississippi Valley...
Latest water vapor imagery shows southwest mid-level flow in place
from the southern Plains northeastward into the lower to mid
Mississippi Valley. A shortwave trough is evident across eastern
parts of the southern Plains, where a complex of strong to severe
thunderstorms is ongoing. The storms are located along the
northwestern edge of a moist airmass where surface dewpoints are in
the upper 60s and lower 70s F. These storms will continue to move
eastward across the remainder of east Texas this evening, and should
affect parts of the Arklatex and lower Mississippi Valley tonight.
The latest RAP analysis shows a corridor of moderate to strong
instability across central and east Texas, with MLCAPE ranging from
near 4000 J/kg in the eastern Texas Hill Country to near 2000 J/kg
in far northeast Texas. The complex of storms will continue to move
eastward toward the instability axis this evening. The storms are
also located on the northwestern edge of a 50 to 65 knot mid-level
jet. The latest WSR-88D VWP at Killeen, Texas is sampling the
western edge of the jet and has 0-6 km shear at 70 knots. A looped
hodograph is also present suggesting that supercells should be
capable of producing tornadoes this evening. In addition, lapse
rates are steep in the mid-levels. This will support large hail.
Hailstones of 2 inches in diameter will be possible with the most
dominant cells. Wind damage will also be likely with supercells and
short bowing line segments.
..Broyles.. 04/13/2022
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