Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 250534
SWODY2
SPC AC 250533

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1233 AM CDT FRI APR 25 2014

VALID 261200Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID-MO VALLEY TO THE
SRN PLAINS...

...SUMMARY...
ISOLATED TO PERHAPS SCATTERED SEVERE THUNDERSTORMS ARE ANTICIPATED
FROM THE MID-MISSOURI VALLEY TO THE SOUTHERN GREAT PLAINS ON
SATURDAY EVENING INTO EARLY SUNDAY. LARGE HAIL IS EXPECTED TO BE THE
PRIMARY HAZARD.

...SYNOPSIS...
A BROAD UPPER-LEVEL TROUGH OFF THE PACIFIC COAST WILL SHIFT INLAND
BY EARLY SAT. A VIGOROUS SHORTWAVE IMPULSE WILL PROGRESS FROM SRN CA
TO THE LEE OF THE SRN ROCKIES WITH A COMPACT SPEED MAX ACROSS THE
DESERT SW EJECTING ONTO THE CNTRL/SRN HIGH PLAINS EARLY SUN. THESE
FEATURES WILL INDUCE LEE CYCLOGENESIS OVER ERN CO WITH A WARM FRONT
ARCING EWD NEAR THE MO VALLEY. THE DRYLINE SHOULD MIX EWD INTO CNTRL
KS AND ACROSS W TX...BEFORE RETREATING WWD DURING THE EVENING. A
PACIFIC COLD FRONT WILL SWEEP EWD AND EVENTUALLY OVERTAKE THE
DRYLINE IN THE SRN HIGH PLAINS EARLY SUN.

...CNTRL/SRN PLAINS...
IN THE WAKE OF A RECENT COLD FRONT INTRUSION TO NEAR THE TX GULF
COASTAL PLAIN...MODIFIED GULF MOISTURE SHOULD BE CONFINED TO TX AT
12Z/SAT. ROBUST LOW-LEVEL MOISTURE ADVECTION IS EXPECTED THROUGH THE
DAY AS FLOW STRENGTHENS BENEATH A STOUT EML. THIS SHOULD YIELD A
BROADENING PLUME OF MIDDLE 50S TO MIDDLE 60S SURFACE DEW POINTS FROM
PARTS OF THE MID/LOWER MO VALLEY SWD TO THE WRN GULF COAST BY SAT
EVENING.

INTENSE SURFACE HEATING WILL OCCUR ALONG/W OF THE DRYLINE WITH UPPER
80S TO MIDDLE 90S TEMPERATURES FROM CNTRL KS TO W TX. AS WEAK
MID-LEVEL HEIGHT FALLS OVERSPREAD THE DRYLINE NEAR 00Z...LOW-LEVEL
CONVERGENCE WILL STRENGTHEN AND SHOULD RESULT IN A FEW DISCRETE
STORMS. THIS ACTIVITY SHOULD INITIALLY BE HIGH-BASED WITH SURFACE
DEW POINT DEPRESSIONS AOA 30 DEG F. VERY STEEP TROPOSPHERIC LAPSE
RATES ALONG WITH A MODERATE COMBINATION OF BUOYANCY/DEEP-LAYER SHEAR
SHOULD SUPPORT SUPERCELLS PRIMARILY PRODUCING LARGE HAIL /SOME
SIGNIFICANT/ AND LOCALLY SEVERE WINDS.

STRONG WARM SECTOR INHIBITION DOES RENDER SUBSTANTIAL UNCERTAINTY IN
OVERALL STORM COVERAGE/SUSTAINABILITY AND TORNADO POTENTIAL DURING
THE EVENING. GUIDANCE VARIES SUBSTANTIALLY WITH THE DEGREE OF
CONVECTIVE SIGNAL FROM THE MINIMALIST NAM/UKMET TO WIDESPREAD GFS.
GIVEN A RETREATING DRYLINE SCENARIO AND LARGER MID-LEVEL HEIGHT
FALLS HOLDING OFF UNTIL OVERNIGHT...CONFIDENCE IS LOW IN HOW
CONVECTION MAY ULTIMATELY EVOLVE. BUT WITH A LLJ STRENGTHENING TO
AOA 50 KT ALONG WITH AN INFLUX OF RICHER MOISTURE...ANY SUSTAINED
DIURNALLY-DRIVEN STORMS MAY PRODUCE A TORNADO BEFORE THE BOUNDARY
LAYER DECOUPLES.

AS LARGE-SCALE ASCENT STRENGTHENS SUBSTANTIALLY EARLY SUN...ELEVATED
TSTMS WILL INCREASE IN COVERAGE FROM THE MID-MO VALLEY TO THE SUN
PLAINS WITH STEEP LAPSE RATES SUPPORTING A LARGE HAIL THREAT. SOME
OF THIS ACTIVITY MAY BECOME SURFACE-BASED ACROSS THE SRN
PLAINS...WHERE SURFACE DEW POINTS INCREASE INTO THE MIDDLE
60S...SUPPORTING POTENTIAL FOR ALL SEVERE HAZARDS.

..GRAMS.. 04/25/2014



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