Boston, MA...Kansas City, MO...St. Louis, MO...Lincoln, NE...Providence, RI...
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
St. Louis, MO...Columbia, MO...St. Charles, MO...St. Peters, MO...Florissant, MO...
Kansas City, MO...Omaha, NE...Lincoln, NE...Des Moines, IA...Overland Park, KS...
New York, NY...Philadelphia, PA...Boston, MA...Newark, NJ...Jersey City, NJ...
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 2 Hail Risk
Area (sq. mi.)
Some Larger Population Centers in Risk Area
Des Moines, IA...Ames, IA...West Des Moines, IA...Quincy, IL...Ankeny, IA...
Des Moines, IA...West Des Moines, IA...Quincy, IL...Ankeny, IA...Urbandale, IA...
Kansas City, MO...Omaha, NE...St. Louis, MO...Lincoln, NE...Overland Park, KS...
Sioux Falls, SD...Topeka, KS...Evansville, IN...Peoria, IL...Billings, MT...
SPC AC 081748
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1248 PM CDT Thu Jul 08 2021
Valid 091200Z - 101200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION
OF THE MIDDLE MISSOURI VALLEY REGION...
Thunderstorms, some with potentially significant severe weather, are
expected Friday afternoon into Friday night across parts of the
central Plains and Mid Missouri Valley. A tornado or two associated
with Tropical Storm Elsa also is possible in the vicinity of the New
England coast through Friday afternoon.
Compact, low-amplitude shortwave trough currently moving through
northern MT will turn southeast and continue through the middle MO
Valley region Friday. By early Friday, a warm front should extend
from a surface low in NE southeast through MO. A cold front will
stretch southwestward from the low through southwest NE into
northeast CO and will likely stall during the day.
...Mid Missouri Valley...
Thunderstorms will likely be in progress early Friday, primarily
within the zone of isentropic ascent north of the warm front from
southern MN through a portion of northern and eastern IA. The early
activity should gradually shift southeast during the day, but will
remain confined to the cool sector. Farther south in warm sector,
dewpoints in the upper 60s to near 70 F will advect northward in
wake of advancing warm front. This will contribute to moderate to
strong instability with 2000-3000 J/kg possible as the boundary
layer warms during the afternoon. The primary forcing for ascent
associated with the southeast-advancing shortwave trough will
probably remain confined to along and north of the warm front.
However, additional storms may develop along this boundary by late
afternoon and especially as the low-level jet strengthens by early
evening. Strong effective shear from 45-50 kt will support some
supercells, but storms may eventually evolve into lines and clusters
as they spread southeast. All severe hazards are possible.
Upslope flow regime is expected to evolve north of stalled front
across the central plains maintaining a corridor of mid 50s to near
60 F dewpoints beneath steep lapse rates and contributing to
moderate instability with up to 2000 J/kg MLCAPE as the boundary
layer destabilizes. Storms are expected to develop within this
regime and spread east through the high Plains. A belt of stronger
flow aloft will contribute to 50+ kt effective bulk shear supportive
of supercells early in the evolution. However, storms may eventually
evolve into one or more MCSs. Large hail and damaging wind will be
the main threats.
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