Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 270529
SWODY2
SPC AC 270528

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 AM CDT WED MAY 27 2015

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE HIGH PLAINS FROM
NEBRASKA TO TX...

...THERE IS A MRGL RISK OF SVR TSTMS FROM TX TO MN...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS NEW ENGLAND...

...SUMMARY...
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS MUCH OF THE CONUS DURING
THE DAY3 PERIOD.  THE GREATEST RISK FOR SEVERE STORMS WILL BE ACROSS
THE GREAT PLAINS FROM WESTERN NEBRASKA SOUTH INTO WEST TEXAS.
STRONG STORMS WILL ALSO DEVELOP ACROSS NORTHERN NEW ENGLAND.

...GREAT PLAINS...

SEVERAL PIECES OF A BROADER LONG-WAVE TROUGH WILL EJECT ACROSS THE
ROCKIES INTO THE HIGH PLAINS THURSDAY AND WEAK 12HR HEIGHT FALLS ARE
EXPECTED ACROSS THE CNTRL/SRN PLAINS DURING THE DAYLIGHT HOURS.
WHILE DEEP-LAYER SHEAR IS NOT FORECAST TO BE PARTICULARLY
STRONG...MODEST SLY LLJ AND STRONG HEATING ALONG DRY LINE SHOULD
PROVE BENEFICIAL FOR UPWARD EVOLVING CONVECTION WITHIN A SHEARED
ENVIRONMENT FAVORABLE FOR AT LEAST STRONG MULTI-CELLS...OR PERHAPS
ISOLATED SUPERCELLS.  LATEST MODEL GUIDANCE IS NOT REAL CLEAR ON
EARLY-DAY CONVECTIVE EVOLUTION AS BOTH THE NAM AND GFS GENERATE
POCKETS OF SUBSTANTIAL CONVECTION WITHIN APPARENT WARM ADVECTION
CORRIDOR ACROSS THE PLAINS.  HOWEVER...MORE FOCUSED TSTM DEVELOPMENT
ACROSS THE HIGH PLAINS SHOULD BE THE PRIMARY THREAT FOR SEVERE WHERE
STEEP LAPSE RATES SHOULD AID INSTABILITY DURING THE LATE
AFTERNOON/EVENING HOURS.  HAIL/WIND ARE THE PRIMARY THREATS ACROSS
THE PLAINS DURING THE DAY2 PERIOD.

...NEW ENGLAND...

STRONG SHORT-WAVE TROUGH WILL MIGRATE INTO THE LOWER GREAT LAKES
REGION BY SUNRISE THURSDAY MORNING WITH SUBSEQUENT MOVEMENT INTO THE
HUDSON VALLEY BY 18Z.  LATEST GUIDANCE SUGGEST A NARROW CORRIDOR OF
STRONG BOUNDARY LAYER HEATING WILL DEVELOP AHEAD OF ASSOCIATED COLD
FRONT FROM THE LOWER HUDSON VALLEY...NEWD INTO NRN MAINE.  WITH
SFC-3KM LAPSE RATES LIKELY APPROACHING 7 C/KM BY EARLY
AFTERNOON...FRONTAL CONVERGENCE WILL PROVE MORE THAN ADEQUATE FOR
SCT CONVECTION...ESPECIALLY ACROSS NRN NEW ENGLAND WHERE FORCING
WILL BE STRONGER.  FORECAST SOUNDINGS SUGGEST GUSTY WINDS ARE
POSSIBLE WITH ORGANIZED LINE SEGMENTS THAT EVOLVE AHEAD OF
PROGRESSIVE FRONT.  AT THIS TIME IT APPEARS SHEAR/INSTABILITY MAY BE
A BIT TOO WEAK TO WARRANT SLGT RISK...HOWEVER HIGHER PROBS MAY BE
REQUIRED IF BUOYANCY IS GREATER THAN EXPECTED.

..DARROW.. 05/27/2015



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