SWODY1
SPC AC 241955
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0255 PM CDT TUE APR 24 2007
VALID 242000Z - 251200Z
..THERE IS A HIGH RISK OF SVR TSTMS LATE THIS AFTN/TONIGHT ACROSS
PARTS OF CNTRL INTO NORTHEAST TEXAS....
..THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
AREAS ACROSS A LARGE PART OF THE CNTRL/SRN PLAINS...INCLUDING PARTS
OF CNTRL/ERN KS AND OK...TX...NW LA...WRN AR...AND SW MO....
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PART OF THE
CNTRL PLAINS INTO THE MIDDLE/LWR MISSISSIPPI VALLEY....
..SYNOPSIS...
DEEP CYCLONE TO THE LEE OF THE CENTRAL ROCKIES IS IN THE PROCESS OF
OCCLUDING. INITIAL IMPULSE EMBEDDED WITHIN SOUTHERN BRANCH CLOSED
LOW/TROUGH HAS ROTATED AROUND THE NORTHEASTERN PERIPHERY OF BROADER
SCALE CIRCULATION...NOW CENTERED OVER SOUTHEASTERN COLORADO...WITH
ANOTHER IMPULSE BEGINNING TO DIG TO THE LEE OF THE SOUTHERN ROCKIES.
..SOUTH CENTRAL PLAINS INTO LOWER MISSOURI VALLEY...
IN THE EXIT REGION OF 70+ KT 500 MB JET STREAK ASSOCIATED WITH
INITIAL IMPULSE...STORMS REMAIN CELLULAR ACROSS PARTS OF NORTH
CENTRAL/NORTHEAST KANSAS...NEAR WARM FRONT EXTENDING EAST OF
CYCLONE...NEAR/NORTH OF THE INTERSTATE 70 CORRIDOR. EMBEDDED WITHIN
DEEP LAYER SOUTHERLY CLOUD BEARING LAYER FLOW...CELLS HAVE BEEN
QUICKLY LIFTING NORTH OF EAST-WEST ORIENTED FRONT...MINIMIZING
TORNADO POTENTIAL TO THIS POINT. HOWEVER...ACTIVITY ALSO APPEARS TO
HAVE BEEN SLOW TO ROOT IN MOIST MIXED BOUNDARY LAYER WITH CAPE OF
1000-1500 J/KG. THIS INSTABILITY COULD INCREASE A BIT FURTHER LATE
THIS AFTERNOON...AND TENDENCY SHOULD BE FOR ACTIVITY TO BECOME
INCREASING SURFACE BASED. LOW-LEVEL FLOW HAS WEAKENED IN WARM
SECTOR ACROSS MUCH OF CENTRAL/EASTERN KANSAS INTO NORTHEAST
OKLAHOMA...BUT LOW-LEVEL HODOGRAPHS AND AMBIENT ENVIRONMENT STILL
APPEAR SUPPORTIVE OF TORNADOES...PARTICULARLY WHERE SURFACE WINDS
ARE BACKED NEAR WARM FRONT.
FARTHER SOUTH...WIND SHIFT...LOWER/MID TROPOSPHERIC COOLING
ASSOCIATED WITH LEAD IMPULSE HAVE PROVIDED FORCING/FOCUS FOR
EVOLVING SQUALL LINE NEAR/EAST OF THE INTERSTATE 35 CORRIDOR ACROSS
CENTRAL OKLAHOMA INTO NORTH CENTRAL TEXAS. THIS IS OCCURRING IN
ADVANCE OF DRY LINE...IN ENVIRONMENT WITH STEEP MID LEVEL LAPSE
RATES AND CAPE OF 1000-2000 J/KG. LOW-LEVEL LAPSE RATES AHEAD OF
ACTIVITY INTO THE LOWER MISSOURI VALLEY AND OZARKS HAVE NOT
STEEPENED STRONGLY...BUT IN PEAK AFTERNOON HEATING...POTENTIAL FOR
FURTHER INTENSIFICATION OF LINE IS LIKELY. LARGE HAIL/DAMAGING WIND
GUSTS APPEAR LIKELY WITH SQUALL LINE...ALONG WITH THE POTENTIAL FOR
ISOLATED TORNADOES EMBEDDED WITHIN AND AHEAD OF LINE.
..CENTRAL TEXAS THROUGH THE ARKLATEX/EXTREME SE OKLAHOMA...
LOW-LEVEL HODOGRAPHS HAVE BECOME MAXIMIZED ACROSS PARTS OF CENTRAL
INTO NORTHEAST TEXAS...WHERE SOUTHERLY LOW-LEVEL JET IN WARM SECTOR
BOUNDARY LAYER...WITH SURFACE DEW POINTS NEAR 70F...REMAINS STRONG.
40+ KT 850 SOUTHERLY FLOW MAY STRENGTHEN FURTHER THROUGH EARLY
EVENING...AS UPSTREAM IMPULSE CONTINUES SOUTHEAST OF THE ROCKIES
INTO WEST TEXAS. WEAK IMPULSE EMBEDDED WITHIN THE SUBTROPICAL
STREAM MAY AID LARGE SCALE FORCING...AS IT LIFTS NORTHEAST OF THE
LOWER RIO GRANDE VALLEY LATER THIS AFTERNOON AND EVENING.
AND...TORNADIC POTENTIAL...INCLUDING THE RISK FOR ISOLATED STRONG
TORNADOES...APPEARS LIKELY TO BECOME HIGH WITH DISCRETE SUPERCELLS
EXPECTED TO CONTINUE DEVELOPING AHEAD OF BROKEN SQUALL LINE
ADVANCING THROUGH CENTRAL/EASTERN TEXAS.
**FOR MORE SPECIFIC INFORMATION CONCERNING ONGOING OR MORE IMMINENT
SEVERE WEATHER THREATS...PLEASE REFER TO LATEST SPC MESOSCALE
DISCUSSIONS/WATCHES.
.KERR.. 04/24/2007
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