680
ACUS03 KWNS 210731
SWODY3
SPC AC 210730
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT SAT JUN 21 2025
VALID 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
UPPER MIDWEST AND NORTHERN GREAT LAKES...
..SUMMARY
STRONG TO POTENTIALLY SEVERE STORMS MAY DEVELOP MONDAY FROM PARTS OF
THE GREAT LAKES INTO THE CENTRAL PLAINS.
..SYNOPSIS
LITTLE CHANGE TO THE LARGE-SCALE PATTERN IS EXPECTED ON MONDAY, WITH
A PERSISTENT UPPER TROUGH OVER THE WESTERN CONUS, AND AN AMPLIFIED
UPPER RIDGE COVERING MUCH OF THE EAST. A SHORTWAVE EJECTING FROM THE
WESTERN TROUGH IS FORECAST TO MOVE QUICKLY NORTHEASTWARD TOWARD
HUDSON BAY BY MONDAY EVENING. IN THE WAKE OF THIS FEATURE, GUIDANCE
GENERALLY DEPICTS ONLY LOW-AMPLITUDE VORTICITY MAXIMA MOVING AROUND
THE PERIPHERY OF THE RIDGE FROM THE CENTRAL/SOUTHERN PLAINS INTO THE
GREAT LAKES.
AT THE SURFACE, A FRONT IS FORECAST TO BE DRAPED FROM THE CENTRAL
PLAINS INTO THE GREAT LAKES. THE NORTHEAST PORTION OF THIS FRONT MAY
CONTINUE TO MOVE EASTWARD THROUGH THE DAY, AS A SURFACE LOW MOVES
ACROSS ONTARIO. TO THE SOUTHWEST, THE FRONT MAY STALL OR BEGIN TO
MOVE NORTHWARD AS A WARM FRONT, AS A WEAK SURFACE WAVE PERSISTS OVER
THE CENTRAL HIGH PLAINS.
..UPPER MIDWEST/GREAT LAKES
POTENTIAL FOR EXTENSIVE CONVECTION ON D2/SUNDAY CREATES SOME
UNCERTAINTY REGARDING FRONTAL POSITION ON MONDAY. LOCALLY STRONG
STORMS MAY BE ONGOING MONDAY MORNING, WITH A GENERAL INCREASE IN
STORM COVERAGE EXPECTED DURING THE AFTERNOON WHERE STRONG HEATING IS
REALIZED IN THE VICINITY OF THE FRONT. STRONGER DEEP-LAYER FLOW WILL
AGAIN BE DISPLACED TO THE COOL SIDE OF THE FRONT, BUT 30-40 KT OF
MIDLEVEL FLOW OVERLAPPING MODERATE TO STRONG BUOYANCY WILL SUPPORT
SOME POTENTIAL FOR ORGANIZED STORMS. MOSTLY UNIDIRECTIONAL
SOUTHWESTERLY FLOW COULD SUPPORT ONE OR MORE FORWARD-PROPAGATING
CLUSTERS, WITH A THREAT OF DAMAGING WIND AND ISOLATED HAIL.
..CENTRAL PLAINS VICINITY
DEEP-LAYER FLOW/SHEAR WILL BE SOMEWHAT WEAKER ACROSS PARTS OF THE
CENTRAL PLAINS, COMPARED TO AREAS FARTHER NORTHEAST. HOWEVER, STRONG
HEATING WILL RESULT IN DEVELOPMENT OF MODERATE TO LOCALLY STRONG
INSTABILITY. SCATTERED STORM DEVELOPMENT IS EXPECTED WITHIN A WEAKLY
CAPPED ENVIRONMENT, AND A FEW MODESTLY ORGANIZED CELLS/CLUSTERS
COULD EVOLVE WITH TIME, POSING A THREAT FOR STRONG TO SEVERE GUSTS
AND ISOLATED HAIL.
SOME WESTWARD MOISTURE TRANSPORT WILL BE POSSIBLE INTO PARTS OF THE
CENTRAL HIGH PLAINS AND FRONT RANGE, WITHIN A POST-FRONTAL REGIME.
ISOLATED STORMS MAY DEVELOP WITHIN THIS REGIME, THOUGH GENERALLY
MODEST MIDLEVEL LAPSE RATES MAY TEND TO LIMIT ROBUST
DESTABILIZATION.
..NORTHERN NEW ENGLAND
STRONG TO EXTREME INSTABILITY WILL AGAIN RESIDE ACROSS PARTS OF THE
NORTHEAST AND NEW ENGLAND MONDAY AFTERNOON, ALONG THE NORTHERN
PERIPHERY OF THE UPPER RIDGE. HOWEVER, THE INFLUENCE OF THE UPPER
RIDGE IS STILL EXPECTED TO LIMIT STORM POTENTIAL THROUGH THE DAY.
THIS REGION WILL CONTINUE TO BE MONITORED FOR THE POSSIBILITY THAT
STORMS DEVELOPING ACROSS QUEBEC MAY AFFECT PARTS OF NORTHERN NEW
ENGLAND, THOUGH THIS SCENARIO IS TOO UNCERTAIN FOR SEVERE
PROBABILITIES AT THIS TIME.
..DEAN.. 06/21/2025
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page