[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 160559
SWODY1
SPC AC 160558

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT WED AUG 16 2006

VALID 161200Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL
PLAINS...

...CNTRL PLAINS...
AN UPPER-LEVEL RIDGE OVER THE MO VALLEY WILL SHIFT EWD TODAY AS A
SHORTWAVE TROUGH MOVES NEWD OUT OF THE CNTRL ROCKIES. A WEAK FRONTAL
BOUNDARY OVER THE SRN PLAINS WILL MOVE NWD EXTENDING FROM NCNTRL KS
INTO SW NEB. CONVERGENCE ALONG THE BOUNDARY COMBINED WITH
LARGE-SCALE ASCENT ASSOCIATED WITH THE SHORTWAVE TROUGH SHOULD
PROVIDE A FOCUS FOR CONVECTIVE DEVELOPMENT DURING THE AFTERNOON.
THUNDERSTORMS APPEAR LIKELY TO INITIATE NEAR THE BOUNDARY IN CNTRL
AND NRN KS WITH CONVECTION EXPANDING NEWD ACROSS CNTRL AND ERN NEB.
ADDITIONAL THUNDERSTORM DEVELOPMENT APPEARS LIKELY ALONG A SFC
TROUGH EXISTING IN NE CO AND WRN NEB.

FORECAST SOUNDINGS ACROSS SRN AND CNTRL NEB THIS AFTERNOON SHOW
SUBSTANTIAL VEERING BELOW 700 MB WITH 0-6 KM SHEAR VALUES IN THE 25
TO 30 KT RANGE. THIS SHOULD BE FAVORABLE FOR ISOLATED SUPERCELLS IN
AREAS WITH THE STRONGEST INSTABILITY. HOWEVER...MOST OF THE
CONVECTION SHOULD REMAIN MULTICELL AS AN MCS ORGANIZES AND MOVES
INTO ERN NEB AND POSSIBLY WRN IA BY EVENING. THE CURRENT THINKING IS
THAT THE GREATEST SEVERE THREAT WILL BE THE MID-AFTERNOON BEFORE THE
CONVECTION BECOMES ELEVATED NORTHEAST OF THE BOUNDARY. ALTHOUGH HAIL
WILL BE POSSIBLE WITH THE STRONGER CELLS...THE MOST PROBABLE SEVERE
THREAT WILL BE WIND DAMAGE JUST AFTER INITIATION NEAR THE BOUNDARY
WHERE LOW-LEVEL LAPSE RATES ARE FORECAST TO BE THE STEEPEST.

FURTHER NORTHWEST ACROSS WRN NEB...ISOLATED TO SCATTERED
THUNDERSTORMS SHOULD INITIATE ALONG A NORTH TO SOUTH SFC TROUGH WITH
THE CONVECTION MOVING EWD INTO WRN NEB DURING THE LATE AFTERNOON.
FORECAST SOUNDINGS IN WRN NEB THIS AFTERNOON SHOW STRONG ENOUGH
VERTICAL SHEAR FOR SEVERE MULTICELLS. THE CONVECTION SHOULD BE THE
STRONGEST IN THE LATE AFTERNOON AND EARLY EVENING AS LOW-LEVEL FLOW
STRENGTHENS ACROSS THE REGION. STEEP LAPSE RATES AND COOLER
MID-LEVEL TEMPS WILL LIKELY FAVOR EITHER A THREAT FOR HAIL AND/OR
ISOLATED WIND DAMAGE WITH THE MORE ORGANIZED STORMS.

...NRN PLAINS...
AN UPPER-LEVEL RIDGE OVER THE PLAINS STATES WILL MOVE INTO THE GREAT
LAKES REGION TODAY AS A SHORTWAVE TROUGH DRIFTS ENEWD INTO THE NRN
PLAINS. A COLD FRONT WILL ADVANCE SEWD ACROSS ND AND THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE ALONG THE BOUNDARY DURING THE
AFTERNOON. FORECAST SOUNDINGS IN ERN ND THIS AFTERNOON SHOW MODERATE
INSTABILITY AND STRONG ENOUGH SHEAR PROFILES FOR ORGANIZED
MULTICELLS. HOWEVER...THE NUMBER OF STORMS THAT WILL INITIATE
REMAINS UNCERTAIN WHICH COULD LIMIT THE SEVERE WEATHER THREAT AREA.
IF A SHORTWAVE CURRENTLY OVER THE NRN ROCKIES TIMES WELL WITH
MAXIMUM INSTABILITY ACROSS ERN ND...A SLIGHT RISK UPGRADE MAY BECOME
NECESSARY IN LATER OUTLOOKS.

...NRN ROCKIES...
A WELL-DEVELOPED UPPER-LEVEL TROUGH OFF THE COAST OF THE PACIFIC
NORTHWEST WILL MOVE INLAND TODAY. THIS WILL SPREAD STRONG
LARGE-SCALE ASCENT EWD INTO ID AND WRN MT WITH SCATTERED
THUNDERSTORM INITIATION LIKELY IN THE HIGHER TERRAIN THIS AFTERNOON.
FORECAST SOUNDINGS THIS AFTERNOON IN THE NRN ROCKIES SHOW STRONG
ENOUGH SHEAR PROFILES FOR SEVERE STORMS. IF ENOUGH INSTABILITY CAN
DEVELOP IN AREAS WHERE CONVECTION FORMS...HAIL AND STRONG WIND GUSTS
WOULD BE POSSIBLE. A SLIGHT RISK AREA MAY BECOME NECESSARY IF
POCKETS OF MODERATE INSTABILITY DEVELOP THIS AFTERNOON ACROSS THE
REGION.

..BROYLES/BOTHWELL.. 08/16/2006