016
ACUS02 KWNS 090600
SWODY2
SPC AC 090558
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT WED JUL 09 2025
VALID 101200Z - 111200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
CENTRAL AND NORTHERN GREAT PLAINS AS WELL AS PORTIONS OF THE
SOUTHEAST...
..SUMMARY
SCATTERED SEVERE THUNDERSTORMS ARE POSSIBLE OVER PARTS OF THE
CENTRAL AND NORTHERN GREAT PLAINS, MAINLY DURING THE LATE AFTERNOON
AND EVENING ON THURSDAY. ADDITIONAL SEVERE THUNDERSTORMS WILL BE
POSSIBLE DURING THE AFTERNOON ACROSS PORTIONS OF THE SOUTHEAST.
.. SYNOPSIS
A COMPLEX EVOLUTION OF THE MID-TO-UPPER LEVEL PATTERN IS EXPECTED TO
UNFOLD ON THURSDAY ACROSS THE CENTRAL UNITED STATES. A DE-AMPLIFYING
SHORT-WAVE TROUGH WILL MOVE FROM NORTHERN UTAH INTO THE CENTRAL
GREAT PLAINS. AT THE SAME TIME, A LARGER-SCALE, POSITIVE-TILT TROUGH
WILL AMPLIFY DURING THE PERIOD ACROSS SOUTHERN CANADA AS IT PUSHES
EAST. THIS WILL RESULT IN AN EFFECTIVE SPLIT-FLOW PATTERN ACROSS THE
NORTH-CENTRAL US.
.. CENTRAL AND NORTHERN GREAT PLAINS
THUNDERSTORMS ARE EXPECTED AT THE START OF THE PERIOD ACROSS EASTERN
PORTIONS OF THE CENTRAL AND NORTHERN GREAT PLAINS, DRIVEN PRIMARILY
BY WARM, MOIST LOW-LEVEL ADVECTION. IN THE WAKE OF THIS CONVECTION,
THE AIRMASS IS EXPECTED TO QUICKLY RECOVER YIELDING MODERATE TO
EXTREME INSTABILITY.
BY LATE AFTERNOON, THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE
TERRAIN OF NORTHEAST COLORADO AND EASTERN WYOMING. AS THE
AFOREMENTIONED LOW-AMPLITUDE SHORT-WAVE TROUGH BEGINS TO EJECT INTO
THE CENTRAL GREAT PLAINS, THESE THUNDERSTORMS SHOULD QUICKLY MOVE
OFF THE TERRAIN AND INTO THE PLAINS. DAMAGING WINDS WILL BE POSSIBLE
WITH THESE STORMS AS THE QUICKLY GROW UPSCALE IN RESPONSE TO THE
INCREASING LARGE-SCALE ASCENT. THE OVERALL DEGREE OF INSTABILITY
WILL ALSO SUPPORT THE POTENTIAL FOR SPORADIC LARGE HAIL.
TO THE NORTH ACROSS NORTH DAKOTA, CONVECTIVE EVOLUTION IS MORE
UNCERTAIN. THE ATMOSPHERE WILL BE EXTREMELY UNSTABLE IN THE PRESENCE
OF A SURFACE BOUNDARY AND APPROACHING LARGE-SCALE ASCENT. DESPITE
THE ABSENCE OF A MORE ROBUST SIGNAL IN THE CONVECTIVE ALLOWING
GUIDANCE FOR AFTERNOON CONVECTION, COARSER-SCALE GUIDANCE SUGGESTS
AT LEAST SCATTERED THUNDERSTORM DEVELOPMENT WILL OCCUR DURING THE
EVENING AND OVERNIGHT HOURS. THESE THUNDERSTORMS WILL BE CAPABLE OF
DAMAGING THUNDERSTORM WINDS WITH AT LEAST SOME POTENTIAL FOR LARGE
HAIL.
.. PORTIONS OF THE SOUTHEAST
THUNDERSTORMS WILL ONCE AGAIN DEVELOP WITHIN A WARM, MOIST, AND
WEAKLY CAPPED ENVIRONMENT. HIGH PRECIPITABLE WATER VALUE (LOCALLY IN
EXCESS OF 2 INCHES) WILL SUPPORT WATER LOADED DOWNDRAFTS GIVING WAY
TO WET DOWNBURSTS CAPABLE OF WIND DAMAGE. A LEVEL 2/SLIGHT RISK WAS
ADDED TO HIGHLIGHT THE AREA OF HIGHEST COVERAGE OF POTENTIAL WET
DOWNBURSTS.
.. PORTIONS OF THE NORTHEAST
DIURNAL HEATING OF A MOIST BOUNDARY LAYER WILL RESULT IN SCATTERED
THUNDERSTORM DEVELOPMENT ACROSS THE REGION. MOST-UNSTABLE CAPE
VALUES GREATER THAN 1000 J/KG AND MODEST EFFECTIVE-LAYER SHEAR
SHOULD SUPPORT THE POTENTIAL FOR SCATTERED WIND DAMAGE. SHOULD
COVERAGE OF THUNDERSTORMS BE GREATER THAN CURRENTLY ANTICIPATED AN
UPGRADE TO LEVEL 2/SLIGHT RISK MAY BE WARRANTED IN SUBSEQUENT
FORECASTS.
..MARSH.. 07/09/2025
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