DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 181721
SWODY2
SPC AC 181719

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1219 PM CDT TUE JUN 18 2013

VALID 191200Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS CNTRL AND ERN MT INTO NWRN
ND...

...SYNOPSIS...
A POTENT SHORTWAVE TROUGH IS FORECAST TO MOVE THROUGH THE BASE OF A
LARGER SCALE TROUGH/ASSOCIATED UPPER LOW OVER THE PACIFIC NW AND
THIS FEATURE IS FORECAST TO ACQUIRE A NEGATIVE-TILT AS IT MOVES INTO
THE NRN ROCKIES/NRN HIGH PLAINS BY WEDNESDAY EVENING. THE MID-LEVEL
AMPLIFICATION OF A RIDGE WILL OCCUR DOWNSTREAM OVER THE CNTRL CONUS
AS A TROUGH EXITS THE ERN SEABOARD INTO THE WRN ATLANTIC. A SURFACE
LOW IS FORECAST TO DEEPEN OVER MT THROUGH THE EARLY HALF OF THE
PERIOD WITH A LEE TROUGH/DRYLINE EXTENDING SWD THROUGH THE CNTRL-SRN
HIGH PLAINS. A COLD FRONT WILL ACCELERATE EWD ACROSS THE NRN HIGH
PLAINS WEDNESDAY NIGHT REACHING THE WRN DAKOTAS BY THURSDAY MORNING.

...NRN ROCKIES/NRN HIGH PLAINS...
LEE CYCLOGENESIS WILL INDUCE THE CONTINUED NWWD TRANSPORT OF
MOISTURE INTO THE NRN HIGH PLAINS AND FEATURE 50S BOUNDARY LAYER
DEWPOINTS. STRONG SURFACE HEATING AHEAD OF THE APPROACHING
MID-LEVEL DISTURBANCE AND VERY STEEP MID-LEVEL LAPSE RATES /8-9 DEG
C PER KM/ WILL RESULT IN 1000-2500 J/KG MLCAPE BY PEAK HEATING
ACCORDING TO THE LATEST MODEL DATA. EXPECTING ISOLD-SCTD STORMS TO
DEVELOP BY THE MID AFTERNOON AND MOVE IN A GENERAL NWD DIRECTION
OWING TO THE MERIDIONAL CHARACTER TO THE MID-UPPER FLOW. THE
PRESENCE OF STEEP LAPSE RATES AND SIZABLE CAPE IN THE -10 TO -30 DEG
C LAYER SHOWN IN FORECAST SOUNDINGS WOULD SUPPORT A LARGE TO VERY
LARGE HAIL THREAT EVOLVING WITH THE MORE INTENSE UPDRAFTS
/SUPERCELLS/. THE PROPENSITY FOR COLD POOLS TO COALESCE TOWARDS
EVENING MAY INCREASE THE SEVERE WIND GUST THREAT AS CLUSTERS OF
STORMS MOVE FROM CNTRL MT TOWARDS THE CANADIAN BORDER AND NERN MT
DURING THE EVENING HOURS.

...GREAT PLAINS...
THE STRENGTHENING OF THE UPPER RIDGE /MID-LEVEL HEIGHT RISES/ OVER
THE CNTRL CONUS CASTS CONSIDERABLE DOUBT IN ACCURATELY PORTRAYING
THE TIMING/LOCATION OF A FEW AREAS OF ISOLD STORMS...AND LITTLE
EVIDENCE SUPPORTS A CHANGE FROM THE PRIOR OUTLOOK TO A CATEGORICAL
SLIGHT RISK OVER A PREFERRED AREA OF THE GREAT PLAINS.
NONETHELESS...A RESERVOIR OF MODERATE TO STRONG INSTABILITY WOULD AT
LEAST SUPPORT A CONDITIONAL POSSIBILITY FOR VIGOROUS STORMS
/SUPERCELLS/ CAPABLE OF A LARGE HAIL/SEVERE WIND GUST THREAT. A
PORTION OF THIS REGION MAY REQUIRE AN INCREASE IN SEVERE
PROBABILITIES IN LATER OUTLOOK UPDATES IF HIGHER CONFIDENCE IN STORM
LOCATION/COVERAGE IS MET. A LINGERING CHANCE FOR ISOLD SEVERE
STORMS MAY OCCUR DURING THE OVERNIGHT ON THE NOSE OF A CNTRL PLAINS
50 KT LLJ.

...NRN GULF COAST...
DUAL FOCUSING MECHANISMS WHICH INCLUDE THE INLAND PENETRATION OF A
SEA BREEZE FRONT AND THE TRAILING PORTION OF THE WRN ATLANTIC FRONT
INTO THE NRN GULF COAST STATES...WILL PROBABLY LEAD TO ISOLD TO
WIDELY SCTD STORMS DURING THE DAY. POOR LAPSE RATES RESULTING IN
WEAK BUOYANCY WILL ACT TO LIMIT UPDRAFT STRENGTH...PRECLUDING LOW
SEVERE PROBABILITIES ATTM.

..SMITH/KERR.. 06/18/2013

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