Kansas City, MO...St. Louis, MO...Des Moines, IA...Overland Park, KS...Kansas City, KS...
Memphis, TN...Tulsa, OK...Minneapolis, MN...St. Paul, MN...Little Rock, AR...
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.
Kansas City, MO...Tulsa, OK...St. Louis, MO...Des Moines, IA...Overland Park, KS...
Memphis, TN...Omaha, NE...Minneapolis, MN...St. Paul, MN...Little Rock, AR...
SPC AC 060559
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1159 PM CST Sun Mar 05 2017
Valid 061200Z - 071200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION
OF THE LOWER TO MIDDLE MISSISSIPPI VALLEY REGION...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF
THE CENTRAL AND SOUTHERN PLAINS INTO THE MIDDLE TO UPPER MISSISSIPPI
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION
OF THE CENTRAL AND SOUTHERN PLAINS TO THE LOWER THROUGH UPPER
Severe thunderstorms are expected mainly late this afternoon or
evening through tonight across a part of the upper and middle
Mississippi Valley to the Ozarks and Mid-South. A greater
concentration of severe thunderstorms may occur across parts of
northwestern Arkansas and southern Missouri Monday evening. Primary
threats will be damaging wind gusts and large hail, but a few
tornadoes will also be possible, especially from extreme northern
Arkansas into southern Missouri.
Synoptic upper trough currently from the northern Rockies to the
Great Basin will continue northeast through the central and northern
Plains during the day and eject negatively tilted into the upper MS
Valley this evening. Surface low will deepen over the eastern
Dakotas into western MN, while trailing cold front merges with the
dry line as it advances through the central plains during the day
and into the MS valley and southern Plains overnight. Warm front
extending east from the low will move northward through the upper MS
valley and Great lakes regions.
...Ozarks through the middle and Upper Mississippi Valley areas...
With initial return of partially modified Gulf moisture, widespread
low clouds are expected in warm sector today, limiting
boundary-layer warming. The 00Z observed raob data from Sunday
evening already show a warm layer associated with a remnant elevated
mixed layer in place across the central Plains and middle MS Valley
region. Northward advection of partially modified Gulf moisture
beneath 7-7.5 C/km mid-level lapse rates will destabilize the
atmosphere during the day with corridor mlcape from 1000-1500 J/kg
expected to evolve from central and southern Plains into the middle
to lower MS Valley. Instability will remain marginal over the upper
MS valley region where moisture return will be more limited.
Initial storms will likely develop over the upper MS Valley region
where deeper forcing attendant to the ejecting shortwave trough will
likely result in erosion of capping inversion along and just ahead
of the cold front. Initial discrete storms should rapidly evolve
into linear segments with damaging wind and hail the primary
threats, though a brief tornado cannot be ruled out.
Given the presence of capping in warm sector and tendency for the
deeper forcing to move into the upper MS Valley, most of the warm
sector from the central plains into the middle to lower MS valley
will remain capped during the day. However, storms will likely
develop along cold front by early evening as this boundary overtakes
the dryline across eastern KS. Initially discrete storms will evolve
into linear segments. Given very strong effective bulk shear
exceeding 50 kt, organized storms are expected including supercells
and bowing linear segments. Large hail and a couple tornadoes will
be the main threats with initial storms. However, as activity
evolves into a dominant linear mode, damaging wind will become the
primary threat, though a couple of qlcs tornadoes will also be
possible with any embedded mesovortices. The best chance for
pre-frontal storm initiation appears to be within confluent flow
regime along conveyor belt and in association with terrain features
from northwestern AR into southern MO where some of the
convective-allowing models initiate discrete cells. Should this
occur during the early evening, large 0-1 km hodographs would
support supercells with low-level mesocyclones and an attendant
threat for a few tornadoes.
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