Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 310722
SWODY3
SPC AC 310721

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0221 AM CDT FRI JUL 31 2015

VALID 021200Z - 031200Z

...THERE IS A MRGL RISK OF SVR TSTMS FROM A PORTION OF THE UPPER
MIDWEST INTO THE GREAT LAKES...

...SUMMARY...
A FEW STRONG TO SEVERE STORMS MAY OCCUR FROM THE UPPER MIDWEST INTO
THE GREAT LAKES REGION ON SUNDAY.

...SYNOPSIS...

FOR SUNDAY THE SYNOPTIC PATTERN WILL REMAIN DOMINATED BY AN UPPER
TROUGH OVER THE ERN U.S. WITH A CORRESPONDING RIDGE OVER THE WRN
STATES. AT THE SFC A WARM FRONT MIGHT ADVANCE A BIT FARTHER NORTH
INTO THE UPPER GREAT LAKES...WHILE A COLD FRONT MOVES SEWD INTO THE
UPPER MS VALLEY.

...UPPER MIDWEST THROUGH GREAT LAKES REGION...

AN MCS MAY BE IN PROGRESS BY 12Z SUNDAY OVER A PORTION OF THE UPPER
MIDWEST INTO THE GREAT LAKES WITHIN ZONE OF ISENTROPIC ASCENT NORTH
OF WARM FRONT. THE EVOLUTION OF THIS ACTIVITY IS UNCERTAIN...BUT IT
SHOULD SHIFT SEWD WITH TIME...POSSIBLY DIMINISHING TOWARD THE OH
VALLEY. FARTHER UPSTREAM OVER THE UPPER MS VALLEY AND GREAT LAKES IN
WAKE OF EARLY STORMS...THE WARM SECTOR IS EXPECTED TO BECOME
MODERATELY UNSTABLE WHERE ERN EXTENSION OF EML OVERLAPS MOIST AXIS
AND WHERE SOME DIABATIC WARMING MAY OCCUR. HOWEVER...THE EML MAY
SERVE TO CAP THE BOUNDARY LAYER WITH WWD AND SWD EXTENT INTO THE
UPPER MS VALLEY. POTENTIAL WILL EXIST FOR STORMS TO REDEVELOP FROM
SERN MN INTO WI ESPECIALLY WHERE THE COLD FRONT INTERSECTS THE
CONVECTIVELY REINFORCED WARM FRONT OR ALONG ANY RESIDUAL OUTFLOW
BOUNDARIES. ACTIVITY WILL SUBSEQUENTLY DEVELOP SEWD...POSSIBLY
GROWING UPSCALE INTO AN MCS. 0-6 KM VERTICAL SHEAR FROM 30-40 KT
WILL BE SUFFICIENT FOR ORGANIZED SEVERE STORMS. HAVE INTRODUCED A
MARGINAL RISK AREA...BUT AN UPGRADE TO HIGHER PROBABILITIES IS
LIKELY AT SOME POINT IN FUTURE UPDATES ONCE UNCERTAINTY REGARDING
EVOLUTION OF EARLY THUNDERSTORMS AND THEIR IMPACT ON THE MESOSCALE
ENVIRONMENT HAS BEEN MITIGATED.

..DIAL.. 07/31/2015




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