DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 120555
SWODY2
SPC AC 120553

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT FRI OCT 12 2012

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN AND CNTRL
PLAINS...NRN OZARKS...MID MO VALLEY AND MID TO UPPER MS VALLEY...

...MID MO VALLEY/UPPER MS VALLEY/ERN KS/MO...
A RATHER POTENT UPPER-LEVEL TROUGH IS FORECAST TO MOVE EWD FROM THE
CNTRL ROCKIES INTO THE SRN AND CNTRL PLAINS SATURDAY. AHEAD OF THIS
SYSTEM...A WELL-DEVELOPED LOW-LEVEL JET WILL TRANSPORT MOISTURE NWD
ACROSS THE SRN AND CNTRL PLAINS DURING THE DAY WITH A WELL-DEFINED
MOIST AXIS SETTING UP FROM NWRN OK EXTENDING NNEWD ACROSS ECNTRL KS
INTO NW MO AND SRN IA WHERE SFC DEWPOINTS ARE FORECAST TO BE IN THE
LOWER TO MID 60S F BY AFTERNOON. SOME THUNDERSTORM ACTIVITY MAY BE
ONGOING SATURDAY MORNING BUT SFC HEATING AND STRONG LARGE-SCALE
ASCENT AHEAD OF THE UPPER-LEVEL TR0UGH SHOULD RESULT IN A RAPID
INCREASE IN CONVECTIVE COVERAGE SATURDAY AFTERNOON. MODEL FORECASTS
SUGGEST A NEARLY CONTINUOUS LINE OF THUNDERSTORMS SHOULD ORGANIZE
AND MOVE EWD ACROSS SCNTRL IA...NRN AND WRN MO AND ERN KS DURING THE
LATE AFTERNOON AND EVENING.

FORECAST SOUNDINGS ALONG THE MOIST AXIS AT 00Z/SUNDAY FROM DES
MOINES SSWWD ACROSS THE KANSAS CITY METRO AND INTO ERN KS SHOW
MUCAPE OF 1000 TO 1500 J/KG WITH SFC DEWPOINTS IN THE MID 60S F.
THIS COMBINED WITH 0-6 KM SHEAR IN THE 50 TO 60 KT RANGE ALONG WITH
850 TO 500 MB LAPSE RATES OF 7.0 TO 7.5 C/KM SHOULD BE FAVORABLE FOR
SUPERCELLS WITH LARGE HAIL AND POSSIBLY SOME TORNADOES. THE
POTENTIAL FOR LARGE HAIL AND TORNADOES MAY BE THE GREATEST EARLY IN
THE EVENT WHEN SUPERCELLS SHOULD TEND TO BE DISCRETE. AS A LINEAR
MCS ORGANIZES IN THE EARLY EVENING...A TRANSITION TO WIND DAMAGE AS
THE PRIMARY THREAT COULD OCCUR. AN ENHANCED THREAT FOR WIND DAMAGE
APPEARS POSSIBLE ACROSS A LARGE AREA FROM NEAR DES MOINES SWD INTO
SE KS AND SW MO. THE WIND DAMAGE THREAT COULD PERSIST THROUGH MUCH
OF THE NIGHT AS THE LINEAR MCS PROGRESSES STEADILY EWD ACROSS THE
SLIGHT RISK AREA.

...SRN PLAINS/OZARKS...
A WELL-ORGANIZED UPPER-LEVEL TROUGH IS FORECAST TO MOVE FROM THE SRN
AND CNTRL ROCKIES EWD INTO THE SRN HIGH PLAINS DURING THE DAY ON
SATURDAY. AHEAD OF THE SYSTEM...A LOW-LEVEL JET WILL TRANSPORT
MOISTURE QUICKLY NWD ACROSS THE SRN AND CNTRL PLAINS WITH A NARROW
AXIS OF MODERATE INSTABILITY DEVELOPING SATURDAY AFTERNOON. SOME
ELEVATED THUNDERSTORM ACTIVITY MAY BE ONGOING ALONG THE WRN EDGE OF
THE INSTABILITY AXIS EARLY IN THE DAY BUT SFC-BASED THUNDERSTORMS
APPEAR LIKELY TO DEVELOP ALONG THE INSTABILITY AXIS BY MID
AFTERNOON. THE MODELS SUGGEST A NEARLY CONTINUOUS LINE OF STORMS
WILL ORGANIZE ACROSS OK BUT THAT CONVECTION SHOULD BE MORE SCATTERED
IN NATURE FROM FAR SRN OK SWD ACROSS NORTH TX NEAR THE SRN EDGE OF
THE LOW-LEVEL JET. THE LINE OF STORMS IN CNTRL OK SHOULD PROGRESS
EWD ACROSS ERN OK DURING THE EVENING AND EARLY OVERNIGHT PERIOD.

FORECAST SOUNDINGS EARLY SATURDAY EVENING NEAR OKLAHOMA CITY AND
WICHITA FALLS SHOW MLCAPE AROUND 1500 J/KG AND SFC DEWPOINTS IN THE
MID 60S F. THIS COMBINED WITH 0-6 KM SHEAR OF 50 TO 60 KT SHOULD BE
FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. LOW-LEVEL SHEAR IS
FORECAST TO BE STRONG WITH 0-1 KM SHEAR AROUND 30 KT SUGGESTING A
TORNADO THREAT MAY ALSO OCCUR WITH THE BETTER ORGANIZED SUPERCELLS.
A WIND DAMAGE THREAT MAY ALSO EXIST WITH SUPERCELLS IN THE RED RIVER
VALLEY DURING THE LATE AFTERNOON AND EARLY EVENING. THE WIND DAMAGE
THREAT SHOULD BE THE GREATEST FROM THE OKLAHOMA CITY METRO EWD TO
THE AR STATE-LINE WHERE A LINEAR MCS IS FORECAST TO DEVELOP. THE
WIND DAMAGE THREAT COULD BECOME ENHANCED ACROSS ECNTRL OK WHERE A 30
PERCENT SEVERE PROBABILITY HAS BEEN INTRODUCED BASED ON THE LATEST
MODEL GUIDANCE WHICH IS MORE AGGRESSIVE ON THE SRN END OF THE LINE.

..BROYLES.. 10/12/2012

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