855
ACUS02 KWNS 201706
SWODY2
SPC AC 201704
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1204 PM CDT SUN APR 20 2025
VALID 211200Z - 221200Z
..NO SEVERE THUNDERSTORM AREAS FORECAST
..SUMMARY
SEVERE THUNDERSTORM POTENTIAL APPEARS LOW ON MONDAY.
..SYNOPSIS
AN UPPER LOW/SHORTWAVE TROUGH OVER THE UPPER MIDWEST ON MONDAY
MORNING WILL LIFT NORTHEAST ACROSS THE GREAT LAKES INTO SOUTHERN
ONTARIO AND WESTERN QUEBEC BY TUESDAY MORNING. MEANWHILE, ANOTHER
UPPER SHORTWAVE TROUGH OVER THE NORTHERN ROCKIES WILL DEVELOP
EASTWARD TO THE NORTHERN PLAINS. AT THE SURFACE, AN AREA OF LOW
PRESSURE WILL MOVE FROM WISCONSIN TO QUEBEC THROUGH THE PERIOD WITH
A TRAILING COLD FRONT MOVING FROM THE OHIO VALLEY TO THE
NORTH-CENTRAL APPALACHIANS AND INTO THE MID-ATLANTIC. THIS FRONT
WILL BE MORE STATIONARY ACROSS THE MID-MISSISSIPPI VALLEY AND MAY
START TO MOVE NORTH BY THE END OF THE PERIOD ACROSS SOUTH-CENTRAL
TEXAS.
...OHIO VALLEY/LOWER GREAT LAKES TO THE TN/LOWER MS
VALLEYS/SOUTHEAST TX...
A NARROW CORRIDOR OF MID 60S DEWPOINTS MAY BE PRESENT ACROSS THE
OHIO VALLEY ON MONDAY WHICH COULD RESULT IN SOME WEAK INSTABILITY
DESPITE EXTENSIVE CLOUD COVER AND POOR LAPSE RATES. ROBUST VERTICAL
SHEAR COULD RESULT IN A FEW STRONGER STORMS CAPABLE OF ISOLATED
DAMAGING WIND GUSTS, BUT THE LIMITED INSTABILITY SHOULD KEEP THE
THREAT MINIMAL OVERALL.
BETTER-QUALITY BOUNDARY LAYER MOISTURE, SLIGHTLY BETTER LAPSE RATES,
AND THE POTENTIAL FOR SOME WARMING MAY RESULT IN GREATER INSTABILITY
FARTHER SOUTH, PERHAPS UP TO 1000 J/KG MLCAPE. HOWEVER, VERTICAL
SHEAR WILL BE VERY WEAK WHERE THIS BETTER INSTABILITY IS FORECAST TO
DEVELOP. A COUPLE OF STRONG STORMS WILL BE CAPABLE OF LOCALLY STRONG
GUSTS OR SMALL HAIL, BUT A LACK OF STRONGER VERTICAL SHEAR WILL
LIKELY LIMIT LONGEVITY OF ANY STRONGER/BETTER ORGANIZED UPDRAFTS,
PRECLUDING SEVERE PROBABILITIES.
..NORTHERN PLAINS
COLD TEMPERATURES ALOFT WITH THE UPPER SHORTWAVE TROUGH WILL SUPPORT
STEEP MIDLEVEL LAPSE RATES FROM MT INTO THE NORTHERN PLAINS
VICINITY. AS WEAK INSTABILITY DEVELOPS ACROSS THE NORTHERN PLAINS,
SCATTERED THUNDERSTORMS ARE POSSIBLE. A WELL-MIXED AIR MASS COULD
SUPPORT AN ISOLATED SEVERE WIND THREAT, PARTICULARLY ACROSS
SOUTHWEST SOUTH DAKOTA AND VICINITY WHERE MID-LEVEL FLOW WILL BE
STRONGEST.
ADDITIONAL THUNDERSTORMS MAY DEVELOP OVERNIGHT ACROSS EASTERN SD
INTO SOUTHERN MN/NORTHERN IA ON THE NOSE OF A DEVELOPING LOW-LEVEL
JET. THIS ACTIVITY MAY PRODUCE SMALL HAIL INTO EARLY TUESDAY
MORNING.
..BENTLEY.. 04/20/2025
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