Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 300442
SWODY2
SPC AC 300441

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1141 PM CDT FRI AUG 29 2014

VALID 311200Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY TO THE
CENTRAL PLAINS...

...SUMMARY...
SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A COLD FRONT FROM
MINNESOTA...SOUTHWEST INTO KANSAS.  LARGE HAIL AND DAMAGING WINDS
ARE EXPECTED WITH THIS ACTIVITY.

...UPPER MS VALLEY TO CNTRL PLAINS...

MODEST MID-LEVEL HEIGHT FALLS WILL SPREAD ACROSS THE NRN/CNTRL
PLAINS SUNDAY IN RESPONSE TO A STRONG TROUGH THAT WILL PROGRESS
ACROSS THE ROCKIES BY MID DAY...THEN INTO THE MID-UPPER MS VALLEY BY
01/12Z.  WHILE THIS TROUGH IS MULTI-FACETED THE PRIMARY SPEED
MAX...50KT+ AT 500MB...OF CONCERN IS FORECAST TO EJECT ACROSS CO
INTO THE CNTRL PLAINS DURING THE EVENING HOURS.  THIS FEATURE SHOULD
ENHANCE CONVECTIVE ORGANIZATION WITHIN STRONGLY DIFLUENT HIGH-LEVEL
FLOW REGIME.

EARLY IN THE PERIOD...ELEVATED THUNDERSTORMS MAY BE ONGOING ALONG
THE NOSE OF LLJ ACROSS THE UPPER RED RIVER VALLEY.  THIS ACTIVITY
SHOULD BE ROOTED AOA 850MB AND THE GREATEST THREAT WITH THESE STORMS
SHOULD BE MARGINALLY SEVERE HAIL BEFORE THEY PROPAGATE INTO SRN
MANITOBA.  HOWEVER...GREATER SEVERE RISK WILL OCCUR ALONG THE COLD
FRONT DURING THE LATE AFTERNOON AS BOUNDARY LAYER WARMS...FORCING
SBCAPE IN EXCESS OF 3000 J/KG FROM CNTRL MN...SWWD INTO KS.  LATEST
THINKING IS FRONTAL CONVECTION SHOULD DEVELOP AFTER 21Z WITHIN AN
INCREASINGLY SHEARED ENVIRONMENT THAT SHOULD INITIALLY SUPPORT
SUPERCELL STRUCTURES.  ACTIVITY ACROSS CNTRL KS MAY BE SOMEWHAT
HIGH-BASED AS TEMPERATURES SOAR INTO THE 90S.  HOWEVER...UPDRAFTS
THAT EVOLVE ACROSS NEB INTO MN WILL BE CONSIDERABLY LOWER AND
MULTIPLE HP SUPERCELLS COULD DEVELOP ALONG THE FRONT BEFORE STORM
MERGERS RESULT IN AN ELONGATED MCS-TYPE COMPLEX.  LARGE HAIL IS
LIKELY WITH THIS ACTIVITY AND DAMAGING WINDS MAY ALSO BE NOTED.  A
FEW TORNADOES CAN NOT BE RULED OUT WITH EARLY DISCRETE SUPERCELL
STRUCTURES.  FRONTAL MCS SHOULD PROGRESS INTO THE MID-UPPER MS
VALLEY DURING THE OVERNIGHT PERIOD.

...ELSEWHERE...

VERY MOIST TROPICAL PLUME WILL ADVANCE INLAND ACROSS THE LOWER MS
VALLEY DURING THE DAY1 PERIOD THEN ADVECT ACROSS THE TN/OH VALLEY
REGION SUNDAY.  NUMEROUS SHOWERS/THUNDERSTORMS SHOULD EVOLVE WITHIN
THIS TROPICAL PLUME CHARACTERIZED BY WEAK LAPSE RATES AND WEAK
BUOYANCY.  FORECAST SHEAR DOES NOT APPEAR ADEQUATE TO WARRANT
MEANINGFUL SEVERE PROBS.

..DARROW.. 08/30/2014



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