DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 221954
SWODY1
SPC AC 221952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SUN APR 22 2007

VALID 222000Z - 231200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MO VALLEY
AND UPPER MIDWEST...

..MO VALLEY/UPPER MIDWEST...
WATER VAPOR IMAGERY CURRENTLY SHOWS A QUICK MOVING NEGATIVELY TILTED
UPPER-LEVEL TROUGH OVER THE CNTRL PLAINS WITH THE UPPER-LOW CENTERED
JUST WEST OF OMAHA NEB. BANDED ZONES OF STRONG LARGE-SCALE ASCENT
ARE PRESENT AROUND THE UPPER-LEVEL TROUGH/LOW WHICH WILL SUSTAIN
SEVERAL LINES OF CONVECTION. THE CONVECTIVE LINES WILL MOVE NEWD
ACROSS THE REGION AND SHOULD EXPAND IN COVERAGE AND INTENSITY
EVENTUALLY AFFECTING ERN IA...WRN WI AND NW IL DURING THE OVERNIGHT
PERIOD.

THE LATEST FORECAST SOUNDINGS AND OBJECTIVE ANALYSIS ACROSS THE
REGION SHOW 0-6 KM SHEAR VALUES PRIMARILY IN THE 5O TO 65 KT RANGE
NEAR THE ONGOING CONVECTION. INSTABILITY REMAINS WEAK BUT SHOULD
INCREASE SOME LATE THIS AFTERNOON AND THE ENVIRONMENT MAY BECOME
SUPPORTIVE OF SUPERCELLS. IF A FEW SUPERCELLS DO DEVELOP LATE THIS
AFTERNOON...THE MOST LIKELY LOCATION WOULD BE FROM NW OF OMAHA NEB
EXTENDING EWD INTO WRN IA WHERE INSTABILITY AND LIFT IS FORECAST TO
BE MAXIMIZED. COLD TEMPS ALOFT MAY BE SUPPORTIVE OF LARGE HAIL
ESPECIALLY WITH SUPERCELLS THAT DEVELOP. IN ADDITION TO LARGE
HAIL...A FEW TORNADOES MAY OCCUR AS THE LOW-LEVEL JET STRENGTHENS
LATE THIS AFTERNOON AND EARLY THIS EVENING. SCATTERED WIND DAMAGE
EVENTS MAY ALSO OCCUR AS THE MCS MOVES NEWD ACROSS THE REGION THIS
EVENING PRIMARILY DUE TO STRONG LOW-LEVEL FLOW AND UNIDIRECTIONAL
WINDS BELOW 850 MB.

..NE TX/SE OK...
LATEST OBJECTIVE ANALYSIS SHOWS AN AXIS OF INSTABILITY LOCATED FROM
ECNTRL TX EXTENDING NEWD INTO SE OK. THIS AXIS SHOULD SHIFT ENEWD
LATE THIS AFTERNOON AND INSTABILITY SHOULD GRADUALLY CONTINUE TO
INCREASE. OBJECTIVE ANALYSIS ALSO SHOWS THE CAPPING INVERSION HAS
WEAKENED ACROSS PARTS OF NCNTRL/NERN TX. ALTHOUGH HIGHLY CONDITIONAL
ATTM...A FEW THUNDERSTORMS STILL MAY INITIATE LATE THIS AFTERNOON
AROUND THE DALLAS/FORT WORTH TX AREA AS MID-LEVEL MOISTURE INCREASES
FROM THE SOUTHWEST. LARGE-SCALE ASCENT WILL REMAIN WEAK BUT SHEAR
VALUES MAY BE MARGINALLY SUFFICIENT FOR HAIL AND STRONG GUSTY WINDS.
ANY MARGINAL SEVERE THREAT WOULD LIKELY BE CONFINED TO A SMALL
WINDOW FROM 22Z TO 01Z.

.BROYLES.. 04/22/2007

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