Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 041713
SWODY2
SPC AC 041712

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT MON MAY 04 2015

VALID 051200Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE SRN HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE CENTRAL HIGH PLAINS
SWD INTO THE SRN PLAINS...

...SUMMARY...
SCATTERED STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE TUESDAY
ACROSS PARTS OF THE CENTRAL HIGH PLAINS INTO THE SOUTHERN PLAINS.

...SYNOPSIS...
A LONG-WAVE TROUGH WILL BECOME ESTABLISHED ACROSS THE WRN HALF OF
THE CONUS TUESDAY AS A LOWER LATITUDE SHORT-WAVE TROUGH NOW OVER THE
LOWER CO VALLEY/NRN BAJA REGION MOVES EWD/NEWD ACROSS THE
CENTRAL/SRN ROCKIES...AND AN UPSTREAM COLD UPPER LOW OFF BC DIGS
SEWD ACROSS BC AND THE PACIFIC NORTHWEST.

AT THE SURFACE...A BROAD LOW PRESSURE AXIS OVER THE WEST WILL
GRADUALLY SHIFT EWD AND BECOME BETTER DEFINED IN THE IMMEDIATE LEE
OF THE ROCKIES.  A NORTH-SOUTH DRY LINE WILL OVER THE CENTRAL/SRN
HIGH PLAINS IS FORECAST TO INITIALLY MIX/SHIFT EWD ACROSS PARTS OF
THE SRN HIGH PLAINS INTO THE EVENING HOURS BEFORE RETREATING WWD
DURING THE NIGHT.

...SRN HIGH PLAINS...
AREAS OF STRONG CONVECTION MAY BE ONGOING EARLY IN THE PERIOD FROM
PARTS OF ERN NM/W TX INTO SWRN KS IN ADVANCE OF THE SWRN STATES
SHORT-WAVE TROUGH. THIS ACTIVITY IS LIKELY TO SPREAD NEWD DURING THE
DAY WITH POTENTIAL FOR MARGINAL HAIL AND OCCASIONAL STRONG WIND
GUSTS. IN THE WAKE OF THE INITIAL CONVECTIVE STORMS...DIABATIC
HEATING OVER ERN NM/W TX WILL COMBINE WITH COOLING ALOFT AND THE ERN
EDGE OF STEEPER MID-LEVEL LAPSE RATES TO PROMOTE STRONGER
INSTABILITY WITH MLCAPE REACHING 1000-1500 J/KG.  REDEVELOPMENT OF
STORMS IS EXPECTED DURING THE AFTERNOON NEAR THE DRY LINE AS DYNAMIC
FORCING FOR LARGE-SCALE ASCENT OVERSPREADS THE AREA FROM THE WEST.
WIND PROFILES ARE EXPECTED TO VEER AND INCREASE IN SPEED WITH HEIGHT
AS A BROAD ZONE OF 35-45 KT MID-LEVEL WINDS ADVANCES NEWD ACROSS THE
SRN HIGH PLAINS.  THIS WILL ENHANCE STORM ORGANIZATION AND INTENSITY
INCLUDING POTENTIAL FOR SUPERCELL STRUCTURES TO DEVELOP.  LARGE
HAIL...DAMAGING WIND GUSTS AND ISOLATED TORNADOES WILL BE POSSIBLE
WITH STRONGER CELLS THROUGH THE EVENING HOURS.  THIS ACTIVITY MAY
ORGANIZE INTO ONE OR MORE LOOSELY ORGANIZED MCS/S THAT WILL CONTINUE
NEWD ACROSS PARTS OF OK INTO KS THROUGH THE OVERNIGHT HOURS...BUT
DECREASING INSTABILITY WITH NEWD EXTENT IS EXPECTED TO LIMIT OVERALL
NOCTURNAL SEVERE POTENTIAL.

FARTHER EAST OVER PARTS OF CENTRAL/N CENTRAL TX...MULTIPLE MODELS
/NAM..GFS..ECMWF..UKMET..EXPERIMENTAL NCAR ENKF ENSEMBLE/ INDICATE
DEVELOPMENT OF A SEPARATE AREA OF STRONG CONVECTION WITHIN A WEAKLY
CAPPED ENVIRONMENT BENEATH A DIFFLUENT MID-UPPER LEVEL FLOW PATTERN.
 AS STRONGER WINDS ALOFT SPREAD EWD TOWARD CENTRAL TX...DEEP-LAYER
SHEAR IS FORECAST TO INCREASE WITH POTENTIAL FOR A FEW STRONG TO
SEVERE STORMS /INCLUDING ISOLATED SUPERCELLS/.  ACCORDINGLY...THE
5%-MARGINAL RISK AND 15%-SLIGHT RISK CONTOURS HAVE BEEN ADJUSTED EWD
INTO PARTS OF CENTRAL/N CENTRAL TX.

..WEISS.. 05/04/2015




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