SPC AC 230535
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1235 AM CDT MON APR 23 2007
VALID 241200Z - 251200Z
...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF CNTRL/ERN KS/OK
AND NERN TX...
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL PLAINS EWD INTO
PARTS OF THE MIDWEST AND SWD INTO SRN TX...
...SYNOPSIS...
LATEST NAM/WRF AND GFS GUIDANCE REMAIN CONSISTENT IN EWD PROGRESSION
OF MID AND UPPER-LEVEL LOW FROM NM/CO INTO OK/KS BY 25/12Z. IN THE
LOW-LEVELS...ATTENDANT SURFACE LOW IS FORECAST TO DEEPEN THROUGH THE
DAY AS IT CONCURRENTLY DEVELOPS EWD FROM SWRN INTO S-CNTRL KS BY
EARLY EVENING...AND THEN INTO FAR SERN KS BY WEDNESDAY MORNING.
ATTENDANT WARM FRONT INITIALLY FROM SURFACE LOW THROUGH CNTRL KS TO
SRN IL WILL STEADILY LIFT NWD...STRETCHING FROM FAR NRN KS THROUGH
NRN MO INTO CNTRL IL BY LATE AFTERNOON/EARLY EVENING.
MEANWHILE...DRYLINE WILL RAPIDLY ADVECT/MIX EWD FROM THE ERN OK/TX
PNHDLS TO VICINITY OF THE I-35 CORRIDOR BY MID AFTERNOON.
...OUTBREAK OF SEVERE STORMS CAPABLE OF TORNADOES /A FEW
SIGNIFICANT/...LARGE HAIL AND DAMAGING WINDS APPEARS LIKELY TUESDAY
AND TUESDAY NIGHT...
...CNTRL/SRN PLAINS...
23/00Z SOUNDINGS FROM BRO/CRP INDICATE A CONSIDERABLE INCREASE TO
BOUNDARY LAYER DEPTH AND MOISTURE CONTENT OVER THE PAST 24 HOURS
WITH MEAN MIXING RATIOS OF 14-15 G/KG. STRENGTHENING SLY LOW-LEVEL
FLOW WILL ALLOW THIS AIR MASS TO BE ADVECTED NWD THROUGH CNTRL/ERN
PORTIONS OF TX/OK/KS WITH A SECONDARY LOW-LEVEL MOISTURE AXIS ALSO
DEVELOPING MORE NNEWD THROUGH THE LOWER/MID MS VALLEY. STEEPENING
MID-LEVEL LAPSE RATES COUPLED WITH DAYTIME HEATING AND THIS MOISTURE
WILL CONTRIBUTE TO A MODERATELY UNSTABLE WARM SECTOR WITH AFTERNOON
MLCAPES OF 1500-2500 J/KG.
CLUSTERS OF POTENTIALLY SEVERE...ELEVATED TSTMS ARE EXPECTED TO BE
ONGOING TUESDAY MORNING WITHIN STRONG LOW-LEVEL WAA REGIME NEAR AND
N OF WARM FRONT ACROSS NRN KS INTO SRN NEB. SURFACE-BASED
CONVECTION MAY TEND TO DEVELOP FAIRLY EARLY IN THE DAY OVER PARTS OF
WRN INTO CNTRL KS AS LARGE-SCALE FORCING FOR ASCENT ACTS ON ONLY A
WEAKLY CAPPED AIR MASS. DESPITE BEING EARLY IN THE DIURNAL HEATING
CYCLE...FORECAST SOUNDINGS INDICATE THAT BOTH THERMODYNAMIC AND
KINEMATIC ENVIRONMENT WILL BE QUITE SUPPORTIVE OF SUPERCELLS CAPABLE
OF TORNADOES AND LARGE HAIL. TSTMS ARE EXPECTED TO INCREASE IN
AREAL COVERAGE TUESDAY OVER CNTRL/ERN KS AS DRYLINE SURGES EWD/NEWD
WITH A CONTINUING THREAT OF TORNADIC SUPERCELLS ALONG DRYLINE...WARM
FRONT AND WITHIN FREE WARM SECTOR.
BY MID TO LATE AFTERNOON...ADDITIONAL STORMS ARE EXPECTED TO
PROGRESSIVELY DEVELOP SWD ALONG DRYLINE NEAR THE I-35 CORRIDOR
/CNTRL OK INTO N-CNTRL TX/ INTO A MODERATELY UNSTABLE BUT STRONGER
CAPPED ENVIRONMENT. HERE TOO...PROXIMITY OF 100-120 KT 250 MB/60-70
KT 500 MB JET STREAKS WILL RESULT IN STRONG VERTICAL SHEAR WITH THE
LIKELIHOOD OF SUPERCELLS CAPABLE OF TORNADOES...LARGE HAIL AND
DAMAGING WINDS.
THE SEVERE STORMS OVER KS/OK ARE EXPECTED TO MOVE RAPIDLY EWD INTO
WRN/CNTRL MO AND WRN AR TUESDAY NIGHT WITH A CONTINUING THREAT OF
TORNADOES...LARGE HAIL AND DAMAGING WINDS. OTHER STORMS /SUPERCELLS
WITH HAIL AND A FEW TORNADOES/ WILL BE POSSIBLE SWWD ALONG DRYLINE
THROUGH CNTRL INTO SWRN TX TUESDAY AFTERNOON INTO EVENING...WITH
THIS THREAT APPROACHING SERN/ERN TX LATE TUESDAY NIGHT.
...LOWER MO/MID MS VALLEYS INTO THE OH VALLEY...
ENVIRONMENT ALONG AND S OF RETREATING WARM FRONT IS EXPECTED TO
BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS CAPABLE OF TORNADOES
AND HAIL TUESDAY AFTERNOON AND NIGHT AS LOW/MID 60S DEWPOINTS
CONTRIBUTE TO MLCAPES OF 700-1500 J/KG. BROAD LOW-LEVEL WAA REGIME
SHOULD SUPPORT A GRADUAL EXPANSION IN TSTMS TUESDAY OVER NRN/CNTRL
MO INTO CNTRL/SRN IL. GIVEN THE RELATIVELY STRONG LOW-LEVEL SHEAR
AND ANTICIPATED STORM MOTIONS LARGELY PARALLEL TO WARM FRONT...THE
POTENTIAL WILL EXIST FOR A COUPLE LONGER-LIVED STORMS CAPABLE OF A
STRONG TORNADO OR TWO.
..MEAD.. 04/23/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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