856
ACUS01 KWNS 310042
SWODY1
SPC AC 310040
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0740 PM CDT MON MAR 30 2026
VALID 310100Z - 311200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID TO UPPER MISSISSIPPI VALLEY...
..SUMMARY
A FEW SEVERE THUNDERSTORMS WITH LARGE HAIL, ARE EXPECTED ACROSS
PARTS OF THE MIDDLE AND UPPER MISSISSIPPI RIVER VALLEY TONIGHT
THROUGH EARLY TUESDAY MORNING. ISOLATED STRONG TO MARGINALLY SEVERE
STORMS COULD OCCUR FARTHER EAST INTO PARTS OF LOWER MICHIGAN EARLY
TUESDAY MORNING, AND OVER THE TEXAS SOUTH PLAINS THIS EVENING.
..MID TO UPPER MISSISSIPPI VALLEY/UPPER MICHIGAN
AT MID-LEVELS, FLOW WILL REMAIN WESTERLY ACROSS MUCH OF THE CENTRAL
U.S. TONIGHT, AS A SUBTLE SHORTWAVE TROUGH MOVES EASTWARD ACROSS THE
LOWER TO MID MISSISSIPPI VALLEY. IN RESPONSE, MOISTURE ADVECTION
WILL INCREASE FROM THE SOUTHERN AND CENTRAL PLAINS NORTHEASTWARD
INTO THE UPPER MIDWEST, AS A 40 TO 50 KNOT LOW-LEVEL JET STRENGTHENS
THIS EVENING AND OVERNIGHT. THE NORTHERN EDGE OF THE LOW-LEVEL JET
WILL BE LOCATED FROM IOWA EASTWARD INTO SOUTHERN WISCONSIN AND
NORTHERN ILLINOIS, WHERE LIFT WILL BE MAXIMIZED. WITHIN THIS ZONE,
ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
EVENING INTO THE OVERNIGHT PERIOD.
ON RADAR, ISOLATED THUNDERSTORMS ARE ALREADY ONGOING ACROSS
EAST-CENTRAL IOWA THIS EVENING. IN THE VICINITY OF THIS STORM, RAP
FORECAST SOUNDINGS EARLY THIS EVENING SHOW A NEAR SURFACE INVERSION,
WITH MUCAPE AROUND 2000 J/KG, EFFECTIVE SHEAR NEAR 40 KNOTS AND
700-500 MB LAPSE RATES AROUND 8 C/KM. THIS WILL BE FAVORABLE FOR A
SEVERE THREAT WITH CELLS THAT INITIATE LATER THIS EVENING. THE
STORMS WILL LIKELY BE ELEVATED AND COULD BECOME SUPERCELLS WITH
POTENTIAL FOR LARGE HAIL. THE GREATEST THREAT FOR LARGE HAIL WILL BE
LOCATED ALONG AND JUST TO THE NORTH OF THE STRONGEST INSTABILITY,
FROM NEAR DES MOINES EAST-NORTHEASTWARD TO THE VICINITY OF CHICAGO
AND MILWAUKEE. HAILSTONES GREATER THAN 2 INCHES WILL BE POSSIBLE
WITH THE STRONGEST OF SUPERCELLS. A MARGINAL WIND-DAMAGE THREAT MAY
ALSO DEVELOP AS CONVECTIVE COVERAGE INCREASES FROM LATE THIS EVENING
INTO THE OVERNIGHT PERIOD.
FURTHER EAST INTO LOWER MICHIGAN, SCATTERED CONVECTIVE INITIATION IS
EXPECTED BY EARLY TUESDAY MORNING. THESE STORMS COULD HAVE AN
ISOLATED THREAT FOR HAIL AND SEVERE WIND GUSTS, BUT THE THREAT IS
EXPECTED TO BE MARGINAL AND MORE LOCALIZED DUE TO WEAKER
INSTABILITY.
..SOUTHERN PLAINS
A SHORTWAVE TROUGH IS EVIDENT ON WATER VAPOR IMAGERY OVER
WEST-CENTRAL KANSAS. LIFT ASSOCIATED WITH THIS FEATURE IS
CONTRIBUTING TO CONVECTIVE DEVELOPMENT ACROSS THE EASTERN TEXAS
PANHANDLE THIS EVENING. THESE STORMS ARE LOCATED JUST TO THE WEST OF
AN AXIS OF MODERATE INSTABILITY, WHERE MLCAPE IS IN THE 1500 TO 2000
J/KG RANGE, ACCORDING TO THE RAP. FORECAST SOUNDINGS NEAR CHILDRESS
HAVE 0-6 KM SHEAR IN THE 35 TO 40 KNOT RANGE, WITH VERY STEEP LOW TO
MID-LEVEL LAPSE RATES NEAR 8.5 C/KM. THIS SHOULD BE FAVORABLE FOR A
MARGINAL WIND-DAMAGE THREAT, WITH ANY THREAT EXPECTED TO PERSIST FOR
A COUPLE MORE HOURS.
..BROYLES.. 03/31/2026
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