Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 010720
SWODY3
SPC AC 010719

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0219 AM CDT SAT AUG 01 2015

VALID 031200Z - 041200Z

...THERE IS A MRGL RISK OF SVR TSTMS OVER A PORTION OF THE NERN
STATES...

...THERE IS A MRGL RISK OF SVR TSTMS OVER A PORTION OF THE CNTRL
PLAINS INTO THE MID MS VALLEY AREA...

...SUMMARY...
A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE OVER THE NORTHEAST
STATES AND A PORTION OF THE CENTRAL PLAINS INTO THE MIDDLE TO UPPER
MISSISSIPPI VALLEY.

...SYNOPSIS...

EMBEDDED WITHIN BASE OF AN UPPER LOW CIRCULATION CENTERED OVER SERN
CANADA...A SHORTWAVE TROUGH AND ATTENDANT UPPER JET WILL CONTINUE
THROUGH THE GREAT LAKES REGION AND INTO THE NERN STATES ACCOMPANIED
BY A COLD FRONT. TRAILING PORTIONS OF THIS BOUNDARY WILL STALL OVER
THE CNTRL PLAINS AREA. MODELS CONTINUE TO INDICATE THAT A VORTICITY
MAXIMUM CURRENTLY OVER THE ERN PACIFIC WILL UNDERCUT WRN U.S. UPPER
RIDGE AND REACH THE CNTRL HIGH PLAINS LATER MONDAY.

...NERN STATES...

MODIFIED CP AIR WITH UPPER 50S TO LOW 60S F DEWPOINTS WILL ADVECT
THROUGH PRE-FRONTAL WARM SECTOR AND CONTRIBUTE TO MODEST 500-1500
J/KG MLCAPE AS THE BOUNDARY LAYER WARMS. A FEW THUNDERSTORMS MAY BE
ONGOING ALONG AND AHEAD OF COLD FRONT WITHIN WARM CONVEYOR BELT OVER
A PORTION OF THE NERN STATES. ADDITIONAL STORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT AS THE ATMOSPHERE DESTABILIZES DURING THE
AFTERNOON. THIS ACTIVITY WILL BE EMBEDDED WITHIN A BELT OF STRONGER
DEEP-LAYER WINDS WITHIN THE UPPER LOW CIRCULATION. THE STRONGER
STORMS WILL BECOME CAPABLE OF PRODUCING DAMAGING WIND AND POSSIBLY
SOME HAIL. HAVE INTRODUCED A MARGINAL RISK AREA FOR THIS
UPDATE...BUT AN UPGRADE TO SLIGHT RISK WILL PROBABLY BE NEEDED IN
LATER OUTLOOKS IF DATA CONTINUE TO INDICATE SUFFICIENT
BOUNDARY-LAYER DESTABILIZATION WILL OCCUR TO SUPPORT A MORE ROBUST
SEVERE THREAT.

...CNTRL PLAINS INTO THE MID-UPPER MS VALLEY...

ATMOSPHERE IS EXPECTED TO BECOME MODERATELY UNSTABLE IN VICINITY OF
STALLED BOUNDARY FROM THE CNTRL PLAINS INTO THE MID MS VALLEY AREA
/MOST LIKELY NEB INTO IA AND NRN MO/. THIS BOUNDARY WILL REMAIN
ALONG SRN FRINGE OF MODEST MID-LEVEL WINDS...BUT SUFFICIENT VEERING
WILL EXIST TO SUPPORT 30-40 KT EFFECTIVE SHEAR. THUNDERSTORM
INITIATION ALONG THE FRONT DURING THE AFTERNOON REMAINS UNCERTAIN
DUE TO WEAK FORCING AND PRESENCE OF A CAP. GREATER CONFIDENCE EXISTS
THAT STORMS WILL DEVELOP AND BECOME MORE WIDESPREAD DURING THE
EVENING AND OVERNIGHT AS THE LLJ STRENGTHENS AND AUGMENTS
CONVERGENCE AND ISENTROPIC ASCENT IN VICINITY OF THE FRONT. THE
STRONGER STORMS MAY PRODUCE DAMAGING WIND AND LARGE HAIL. THIS AREA
WILL CONTINUE TO BE MONITORED FOR A POSSIBLE SLIGHT RISK IN LATER
OUTLOOKS.

..DIAL.. 08/01/2015



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