SWODY2
SPC AC 121716
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1216 PM CDT FRI OCT 12 2007
VALID 131200Z - 141200Z
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL
PLAINS...
..SYNOPSIS...
A STRONG UPPER TROUGH WILL SPREAD ENEWD FROM THE DESERT SW/GREAT
BASIN ACROSS THE FOUR CORNERS REGION TOWARD THE CENTRAL/SRN HIGH
PLAINS DURING DAY 2 FORECAST PERIOD. HEIGHT FALLS WITH THIS SYSTEM
WILL SUPPORT A LEE CYCLONE OVER SERN CO WHICH SHOULD TRACK NEWD
THROUGH WRN KS SATURDAY NIGHT. A WARM FRONT WILL EXTEND EWD THROUGH
NRN KS TO THE LOWER MO RIVER VALLEY...WHILE A DRY LINE EXTENDS SWD
FROM WRN KS TO W TX SATURDAY AFTERNOON.
..ERN CO/PARTS OF CENTRAL AND SRN NEB SWD TO TX PANHANDLE...
NWD RETURN OF MODIFIED CP AIR MASS WILL CONTINUE INTO DAY 2...BUT
SHOULD REACH FARTHER N INTO THE CENTRAL PLAINS WITHIN SLY LOW LEVEL
FLOW TO THE EAST OF CO SURFACE LOW. MODEST MOISTURE RETURN BENEATH
PLUME OF STEEP MID LEVEL LAPSE RATES /ELEVATED MIXED LAYER/
EXTENDING EWD ACROSS THE CENTRAL PLAINS SUGGESTS WARM SECTOR WILL
PROBABLY REMAIN CAPPED TO SURFACE BASED STORMS MUCH OF THE DAY.
HOWEVER...BY LATE AFTERNOON EXIT REGION OF CYCLONICALLY CURVED MID
LEVEL JET WILL ADVANCE EWD INTO THE CNTRL HIGH PLAINS. UPPER
DIVERGENCE AND MID LEVEL ASCENT ATTENDING THIS FEATURE WILL LIKELY
CONTRIBUTE TO THE DEVELOPMENT OF STORMS OVER THE HIGHER TERRAIN AND
IN THE MORE DEEPLY MIXED REGIME OVER THE CNTRL HIGH PLAINS. THIS
ACTIVITY MAY INTENSIFY AS IT SPREADS EWD INTO THE MOIST AXIS. DEEP
LAYER SHEAR PROFILES WILL BE SUPPORTIVE FOR SUPERCELLS WITH
POTENTIAL FOR LARGE HAIL AND ISOLATED DAMAGING WIND.
THE SRN EXTENT OF THE SLIGHT RISK AREA ACROSS PARTS OF WEST CENTRAL
INTO SWRN KS IS FORECAST TO BE CONDITIONAL FOR SEVERE STORMS. ALL
MORNING MODEL RUNS...EXCEPT THE 12Z NAM WHICH INDICATED GREATER
MOISTURE RETURN...SHOWED THE BOUNDARY LAYER REMAINING CAPPED BENEATH
ELEVATED MIXED LAYER AND NO TSTM DEVELOPMENT UNTIL AT LEAST 14/06Z.
EVEN THE MORE MOIST AND UNSTABLE NAM DID NOT INDICATE CONVECTIVE
DEVELOPMENT SWD INTO KS UNTIL 14/06-09Z. THIS IS LIKELY DUE TO THE
LOWER MOISTURE CONTENT OF THE MODIFIED CP AIR MASS RETURNING NWD.
HOWEVER...THERE IS SOME INDICATION FOR WEAK FORCING TO SPREAD EWD
INTO WRN KS TO THE OK/TX PANHANDLES BY 14/00Z AHEAD OF APPROACHING
UPPER TROUGH. THIS WOULD SUPPORT POTENTIAL FOR ISOLATED TSTMS...
SOME SUPERCELLS...AS DEEP LAYER SHEAR INCREASES THROUGH THE DAY
ACROSS NARROW INSTABILITY AXIS ALONG AND E OF THE DRY LINE. IN
ADDITION TO CONDITIONAL HAIL/DAMAGING WIND THREAT ACROSS THIS AREA
OF KS TO OK/TX PANHANDLES...STRENGTHENING SLY LLJ FROM W TX TO KS
SATURDAY EVENING IN RESPONSE IN PART TO STRONG HEIGHT FALLS WILL
ALLOW FOR INCREASING LOW LEVEL DIRECTIONAL SHEAR FOR TORNADO THREAT.
THUS...GIVEN CONDITIONAL THREAT FOR SEVERE WEATHER...THIS OUTLOOK
HAS EXTENDED THE SLIGHT RISK AREA SWD INTO PART OF WRN KS.
SATURDAY NIGHT...STORMS ARE EXPECTED TO INCREASE NORTH OF WARM FRONT
ACROSS NEB WITHIN ZONE OF WARM ADVECTION AND LIFT ATTENDING
STRENGTHENING SLY LOW LEVEL JET. THIS ACTIVITY WILL LIKELY BE
ELEVATED WITH A THREAT FOR MAINLY LARGE HAIL.
.PETERS.. 10/12/2007
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