805
ACUS02 KWNS 200518
SWODY2
SPC AC 200517
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1217 AM 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.
...OHIO VALLEY/LOWER GREAT LAKES TO THE TN/LOWER MS
VALLEYS/SOUTHEAST TX...
A BELT OF MODERATE SOUTHWESTERLY DEEP-LAYER FLOW ASSOCIATED WITH THE
GREAT LAKES UPPER TROUGH WILL OVERSPREAD MUCH OF THE OHIO VALLEY
INTO THE MID-ATLANTIC/NORTHEAST. AT THE SURFACE, LOW PRESSURE WILL
MOVE IN TANDEM WITH THE UPPER TROUGH FROM WI TO WESTERN QUEBEC, WITH
A TRAILING COLD FRONT DEVELOPING EAST ACROSS THE OHIO VALLEY TO THE
NORTH-CENTRAL APPALACHIANS/MID-ATLANTIC VICINITY. A NARROW CORRIDOR
OF 250-500 J/KG MLCAPE MAY DEVELOP AHEAD OF THE FRONT ACROSS THE
UPPER OHIO VALLEY VICINITY. WHILE INSTABILITY AND LAPSE RATES AND
WILL REMAIN POOR, ROBUST VERTICAL SHEAR MAY ALLOW FOR A FEW STRONGER
STORMS CAPABLE OF PRODUCING LOCALLY STRONG WIND GUSTS.
THE SOUTHERN EXTENT OF THE AFOREMENTIONED COLD FRONT WILL STALL OVER
THE TN/LOWER MS VALLEY AND INTO SOUTHEAST TX. BETTER-QUALITY
BOUNDARY LAYER MOISTURE WILL RESIDE AHEAD OF THE BOUNDARY THIS FAR
SOUTH, RESULTING IN UP TO 1000 J/KG MLCAPE. HOWEVER, VERTICAL SHEAR
WILL BE VERY MODEST. 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. THIS WILL SUPPORT THUNDERSTORM DEVELOPMENT DURING THE
AFTERNOON INTO EVENING. WHILE INSTABILITY WILL REMAIN WEAK, SMALL
HAIL MAY ACCOMPANY STRONGER THUNDERSTORM CORES ACROSS MT INTO THE
WESTERN DAKOTAS. ADDITIONAL THUNDERSTORMS MAY DEVELOP OVERNIGHT
EASTERN SD INTO SOUTHERN MN/NORTHERN IA ON THE NOSE OF A DEVELOPING
LOW-LEVEL JET. THIS ACTIVITY ALSO MAY PRODUCE SMALL HAIL INTO EARLY
TUESDAY MORNING.
..LEITMAN.. 04/20/2025
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