Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS03 KWNS 030747
SWODY3
SPC AC 030746

DAY 3 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0246 AM CDT THU SEP 03 2015

VALID 051200Z - 061200Z

...THERE IS A MRGL RISK OF SVR TSTMS OVER A PORTION OF THE NRN
PLAINS INTO THE UPPER MS VALLEY...

CORRECTED FOR OUTLOOK GRAPHIC

...SUMMARY...
A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE OVER A PORTION OF THE
NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY SATURDAY AFTERNOON
AND EVENING.

...SYNOPSIS...

UPPER LOW OVER THE NWRN U.S. IS FORECAST TO MOVE THROUGH THE NRN
ROCKIES DURING THE DAY SATURDAY...REACHING THE NRN HIGH PLAINS VERY
LATE SATURDAY NIGHT AND EARLY SUNDAY MORNING. AHEAD OF THIS FEATURE
ANOTHER IN A SERIES OF LOW-AMPLITUDE SHORTWAVE TROUGHS WILL MOVE
NEWD THROUGH THE NRN PLAINS AND UPPER MS VALLEY REGION. BY 12Z
SATURDAY A COLD FRONT SHOULD EXTEND FROM NWRN MN THEN SWWD AS A
STATIONARY FRONT THROUGH SRN ND OR NRN SD AND WWD TO A SFC LOW OVER
NRN WY. A COLD FRONT WILL EXTEND FROM THIS LOW SWWD INTO THE GREAT
BASIN AREA. PRIMARY SFC LOW IS FORECAST TO CONSOLIDATE AND DEEPEN
OVER SERN MT LATER SATURDAY IN RESPONSE TO FORCING ACCOMPANYING THE
PRIMARY UPPER TROUGH. THE ATTENDANT PACIFIC COLD FRONT WILL REACH
THE WRN DAKOTAS LATE SATURDAY NIGHT.


...ERN DAKOTAS THROUGH WRN AND NRN MN....

A MOIST WARM SECTOR WILL BE IN PLACE EARLY SATURDAY FROM THE ERN
DAKOTAS INTO MN WHERE MID-UPPER 60S DEWPOINTS WILL RESIDE. SOME
THUNDERSTORMS WILL PROBABLY BE ONGOING WITHIN ZONE OF ISENTROPIC
ASCENT ESPECIALLY NORTH OF THE FRONT FROM NRN ND AND ON NOSE OF LLJ
ACROSS PORTIONS OF MN. WARM SECTOR IS EXPECTED TO BECOME MODERATELY
UNSTABLE...BUT BOUNDARY-LAYER DESTABILIZATION COULD POSSIBLY BE
LIMITED BY AREAS OF WIDESPREAD CLOUDS DURING THE DAY. POTENTIAL WILL
EXIST FOR STORMS TO INTENSIFY IN VICINITY OF STALLED FRONT FROM ERN
SD INTO SERN ND DURING THE AFTERNOON WITH ADDITIONAL ACTIVITY
POSSIBLY DEVELOPING ALONG WARM CONVEYOR BELT INTO MN DURING THE
EVENING. A MODEST MID-LEVEL JET ACCOMPANYING THE LEAD SHORTWAVE
TROUGH WILL CONTRIBUTE 30-40 KT EFFECTIVE SHEAR SUPPORTIVE OF
ORGANIZED STORMS WITH A THREAT FOR MAINLY DAMAGING WIND AND LARGE
HAIL. AN UPGRADE TO SLIGHT RISK WILL PROBABLY BE NEEDED IN LATER
OUTLOOKS FOR A PORTION OF THIS REGION...BUT PRIMARY UNCERTAINTY AT
THIS TIME IS EVOLUTION AND EXTENT OF EARLY STORMS.

...CNTRL THROUGH ERN MT...

SOME THREAT FOR SEVERE STORMS MAY EVOLVE OVER ERN MT INTO NERN WY
SATURDAY EVENING WHERE ELY POST-FRONTAL FLOW WILL RESULT IN HIGHER
DEWPOINTS AND AT LEAST MODEST INSTABILITY IN THIS REGION. STORMS MAY
DEVELOP ALONG EWD ADVANCING COLD FRONT AND NORTH OF STATIONARY FRONT
WITH A THREAT FOR HAIL AND STRONG WIND GUSTS.

..DIAL.. 09/03/2015




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