[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 270602
SWODY1
SPC AC 270600

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT SAT MAY 27 2006

VALID 271200Z - 281200Z

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

...NRN PLAINS...
AN UPPER-LOW AND ASSOCIATED TROUGH WILL DRIFT EWD INTO THE NRN
ROCKIES AND FOUR CORNERS REGION THROUGH SATURDAY. SWLY FLOW WILL
REMAIN IN PLACE ACROSS THE NRN PLAINS AS MID-LEVEL FLOW GRADUALLY
STRENGTHENS ACROSS THE REGION. AHEAD OF THE TROUGH...WIDESPREAD
LARGE-SCALE ASCENT WILL SUPPORT THUNDERSTORM DEVELOPMENT SATURDAY
AFTERNOON NEAR A SFC LOW AND FRONTAL BOUNDARY EXTENDING ENEWD ACROSS
NRN ND. SFC DEWPOINTS NEAR 60 F SHOULD RESULT IN STRONG INSTABILITY
ALONG AND SOUTH OF THE BOUNDARY. AS STORMS ORGANIZE AND MOVE EWD
ALONG THE GRADIENT IN INSTABILITY...MCS DEVELOPMENT APPEARS LIKELY
BY SATURDAY EVENING ACROSS NRN AND ERN ND INTO NRN MN.

FORECAST SOUNDINGS ACROSS THE REGION LATE SATURDAY AFTERNOON SHOW
MODERATE TO STRONG VERTICAL SHEAR PROFILES WITH STEEP MID-LEVEL
LAPSE RATES SUGGESTING SUPERCELLS WITH LARGE HAIL WILL BE LIKELY.
BECAUSE OF THE VERY UNSTABLE AIRMASS...VERY LARGE HAIL WILL ALSO BE
POSSIBLE WITH THE STRONGER SUPERCELLS. IN ADDITION...A FEW TORNADOES
MAY OCCUR WITH SUPERCELLS THAT PARALLEL THE BOUNDARY AS AN
IMPRESSIVE 45-55 KT LOW-LEVEL JET STRENGTHENS IN THE LATE AFTERNOON
AND EARLY EVENING. A STRONG TORNADO REMAINS POSSIBLE NORTHEAST OF
THE SFC LOW ESPECIALLY IF STORMS REMAIN DISCRETE AND SFC DEWPOINTS
REACH THE LOWER 60S F ACROSS NERN ND BY LATE AFTERNOON. IF STORMS
DEVELOP INTO A LINEAR ORIENTATION...THEN THE WIND DAMAGE THREAT
WOULD ALSO BE ENHANCED IN THE EVENING. AN ISOLATED SEVERE THREAT MAY
CONTINUE OVERNIGHT AS THE MCS TRACKS EWD ACROSS NRN MN CONSIDERING
THE AMOUNT OF INSTABILITY FORECAST ACROSS THE REGION.

...SRN PLAINS...
SOUTHWEST FLOW WILL REMAIN IN PLACE ACROSS THE SRN PLAINS THROUGH
SATURDAY. AT THE SFC...A TROUGH IS FORECAST TO BE LOCATED ACROSS WRN
KS AND WEST TX WITH DEWPOINTS EAST OF THE TROUGH IN THE 60S F. THIS
SHOULD RESULT IN MODERATE TO STRONG INSTABILITY BY LATE AFTERNOON
EAST OF THE TROUGH. A CAPPING INVERSION SHOULD WEAKEN ENOUGH BY LATE
AFTERNOON FOR THE INITIATION OF A FEW ISOLATED STORMS ACROSS WRN
KS...WRN OK...THE ERN TX PANHANDLE AND WCNTRL TX. ALTHOUGH FORECAST
SOUNDINGS SHOW 0-6 KM SHEAR VALUES GENERALLY BELOW 3O KT...THE STEEP
LAPSE RATES AND AMOUNT OF INSTABILITY MAY BE ENOUGH FOR A FEW
MARGINALLY SEVERE STORMS IN THE LATE AFTERNOON OR EARLY EVENING.

...SERN STATES...
AN UPPER-LEVEL RIDGE WILL BE IN PLACE ACROSS THE OH AND TN VALLEYS
THROUGH SATURDAY. AT THE SFC...A BOUNDARY IS FORECAST TO BE IN PLACE
FROM WRN TN EXTENDING SEWD ACROSS AL AND GA. AS SFC TEMPS WARM
SATURDAY...CONVECTION SHOULD INITIATE ALONG THE BOUNDARY AND MOVE
SWD ACROSS THE REGION. FORECAST SOUNDINGS SHOW MODERATE TO STRONG
INSTABILITY WITH WEAK VERTICAL SHEAR PROFILES. THIS SUGGESTS STORM
MODE WILL BE PULSE IN NATURE. ALTHOUGH A CLUSTER OF STORMS WITH HAIL
AND/OR ISOLATED WIND DAMAGE MAY STILL OCCUR...IT IS TOO EARLY TO
IDENTIFY AN AREA WITH ENHANCED SEVERE POTENTIAL. UPGRADE TO SLIGHT
RISK MAY BE NECESSARY ACROSS PARTS OF THE REGION ONCE THE AMOUNT OF
INSTABILITY AND LOCATION OF MCS DEVELOPMENT BECOMES MORE CERTAIN.

..BROYLES.. 05/27/2006