Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 290731
SWODY3
SPC AC 290730

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT MON JUN 29 2015

VALID 011200Z - 021200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE NERN
U.S....

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE MID MS VALLEY TO THE
TN VALLEY...

...SUMMARY...
ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED WEDNESDAY AFTERNOON FROM
EASTERN PENNSYLVANIA TO VERMONT AND NEW HAMPSHIRE.  SCATTERED
STORMS...A FEW SEVERE...WILL ALSO DEVELOP FROM THE MID MISSISSIPPI
VALLEY INTO THE TENNESSEE VALLEY.

...NERN U.S...

SIGNIFICANT SHORT-WAVE TROUGH IS EXPECTED TO EJECT ACROSS THE UPPER
OH VALLEY INTO UPSTATE NY/CNTRL PA BY 18Z...THEN INTO SRN NEW
ENGLAND BY 02/00Z.  IN RESPONSE TO THIS FEATURE...RELATIVELY
COOL/STABLE BOUNDARY LAYER AIR MASS OVER NEW ENGLAND SHOULD BE
DISLODGED ACROSS SRN NEW ENGLAND AS WARM FRONT ADVANCES TO NEAR THE
MAINE BORDER BY LATE AFTERNOON.  VEERING WINDS WITHIN THE
BOUNDARY-LAYER SHOULD ALLOW STEEPENING LOW-LEVEL LAPSE RATES BENEATH
SEASONALLY STRONG MID-LEVEL FLOW...ON THE ORDER OF 50KT AT 500MB.
WILL INTRODUCE MRGL SEVERE THREAT AHEAD OF SHORT WAVE AS LARGE-SCALE
ASCENT AND FRONTAL CONVERGENCE SHOULD AID SCT THUNDERSTORM
DEVELOPMENT WITHIN STRONGLY SHEARED ENVIRONMENT FAVORABLE FOR
DAMAGING WINDS AND PERHAPS SOME HAIL.

...MID MS VALLEY TO TN VALLEY...

BOTH THE GFS AND NAM SUGGEST MCS MAY BE ONGOING AT THE BEGINNING OF
THE PERIOD ALONG NOSE OF VEERED BUT SIGNIFICANT LLJ.  NW-SE ORIENTED
WARM ADVECTION RIBBON SHOULD PROVE FAVORABLE FOR THUNDERSTORM
CLUSTER TO PROPAGATE ACROSS MO INTO KY.  WHILE 5 PERCENT SEVERE
PROBS HAVE BEEN INTRODUCED FOR THIS REGION...SLGT RISK MAY BE
WARRANTED IN LATER OUTLOOKS AS VEERING WINDS WITH HEIGHT AND
SUFFICIENT SPEED SHEAR APPEAR FAVORABLE FOR POTENTIALLY MORE
WIDESPREAD ORGANIZED SEVERE THREAT.  SEVERE WIND GUSTS AND HAIL ARE
EXPECTED WITH THIS ACTIVITY.

..DARROW.. 06/29/2015




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