Schweizer Sturmforum

***SUPERCELLS WITH LONG-TRACK STRONG TORNADOES AND VERY LARGE HAIL
EXPECTED MONDAY LATE AFTN/EVENING ACROSS PARTS OF CNTRL/N OK...SE KS
AND SW MO***

AS STORMS MOVE OUT OF THE DRYLINE CIRCULATION...LARGELY
PERPENDICULAR DEEP-LAYER WIND VECTORS...MLCAPES TO 3000 J/KG AND
EFFECTIVE SHEAR 50-70 KTS WILL FAVOR DISCRETE SUPERCELLS WITH VERY
LARGE HAIL. FCST HODOGRAPHS EXHIBIT VERY STRONG LOW-LEVEL SRH IN
EXCESS OF 400 M2/S2 AND GIVEN ANTICIPATED STORM MODE...INCREASE IN
THE NOCTURNAL EVENING LLJ AND LOWERING LCL/S...LONG-TRACK STRONG
TORNADOES WILL BE POSSIBLE... PARTICULARLY FROM OK PORTION OF
I-40/44 NWD INTO SCNTRL/SERN KS DURING THE EARLY EVENING.

MLCAPES TO 3000 J/KG AND
EFFECTIVE SHEAR 50-70 KTS WILL FAVOR DISCRETE SUPERCELLS WITH VERY
LARGE HAIL

SPC AC 100558

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT MON MAY 10 2010

VALID 101200Z - 111200Z

...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF SE KS AND ERN
OK...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL AND ERN
KS...CNTRL AND ERN OK...WRN MO AND NW AR...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND
CNTRL PLAINS...MID-MS VALLEY AND OZARKS...

...REGIONAL TORNADO OUTBREAK AND LONG-TRACK STRONG TO VIOLENT
TORNADOES BECOMING LIKELY IN ERN OK AND SE KS FROM LATE THIS
AFTERNOON INTO THE EVENING...

...SRN AND CNTRL PLAINS...
RAPID MOISTURE TRANSPORT WILL TAKE PLACE TODAY ACROSS THE SRN PLAINS
AS AN IMPRESSIVE NEGATIVELY-TILTED UPPER-LEVEL TROUGH MOVES QUICKLY
INTO THE REGION FROM THE WEST. SCATTERED THUNDERSTORMS SHOULD BE
ONGOING ON THE NOSE OF A 50 TO 60 KT LOW-LEVEL JET ACROSS ERN KS
WITH THIS CONVECTION BEING SHUNTED NNEWD AWAY FROM THE HIGH RISK
AREA AROUND MIDDAY. AT THIS TIME...A WELL-DEFINED MOIST AXIS AND
DRYLINE WILL RAPIDLY ORGANIZE MOVING ENEWD ACROSS WRN OK THIS
AFTERNOON. SFC DEWPOINTS ARE FORECAST TO RAPIDLY INCREASE INTO THE
UPPER 60S TO AROUND 70 F ACROSS ECNTRL OK WHERE FORECAST SFC TEMPS
SHOULD REACH THE MID TO UPPER 80S F. THIS RESULTS IN A TONGUE OF
STRONG INSTABILITY FROM NRN TX EXTENDING NWD INTO NRN OK WITH MLCAPE
VALUES IN THE 3000 TO 4000 J/KG RANGE. AS THE UPPER-LEVEL TROUGH
APPROACHES THE INSTABILITY AXIS...A 75-90 KT MID-LEVEL JET WILL MOVE
EWD ACROSS NRN OK. THIS FEATURE WILL CREATE VERY STRONG DEEP LAYER
SHEAR PROFILES WITH 0-6 KM SHEAR VALUES ACROSS THE HIGH RISK AREA
REACHING THE 70 TO 80 KT RANGE. THIS COMBINED WITH THE STRONG
INSTABILITY SHOULD RESULT IN RAPID SUPERCELL INITIATION AS STORMS GO
UP ALONG THE DRYLINE ON THE WRN EDGE OF THE LOW-LEVEL JET LATE THIS
AFTERNOON.

THE LOW-LEVEL JET WILL CREATE VERY STRONG LOW-LEVEL SHEAR PROFILES
WITH FORECAST SOUNDINGS ACROSS THE HIGH RISK AREA AT 00Z SHOWING 0-3
KM HELICITIES IN THE 450 TO 550 M2/S2 RANGE SUGGESTING THE SHEAR
ENVIRONMENT WILL BE VERY FAVORABLE FOR TORNADOES. THE CURRENT
THINKING IS THAT SEVERAL SUPERCELLS WILL INITIATE ALONG THE I-35
CORRIDOR FROM WICHITA SWD TO OKLAHOMA CITY WITH THE CELLS BECOMING
TORNADIC TRACKING ENEWD ALONG THE I-44 CORRIDOR INTO THE TULSA AREA
AND INTO FAR SE KS BY EARLY EVENING. STORM MOTIONS SHOULD BE TO THE
EAST NORTHEAST AT 50 KT SUGGESTING THE TORNADOES COULD BE LONG-TRACK
WITH STRONG TO VIOLENT TORNADOES CERTAINLY POSSIBLE ACROSS THE HIGH
RISK AREA. FORECAST SOUNDINGS SHOW VERY STEEP MID-LEVEL LAPSE RATES
WHICH COMBINED WITH THE STRONG VERTICAL SHEAR SHOULD SUPPORT VERY
LARGE HAIL WITH SUPERCELLS THAT DEVELOP ALONG THE DRYLINE. THIS
THREAT SHOULD EXIST SSWWD INTO NRN AND WCNTRL TX WHERE SUPERCELLS
MAY ALSO PRODUCE A FEW TORNADOES.

FURTHER NORTH IN THE CNTRL PLAINS...THUNDERSTORMS SHOULD ALSO
INITIATE NORTH OF SFC LOW IN CNTRL AND NRN KS LATE THIS AFTERNOON.
FORECAST SOUNDINGS ACROSS NRN KS SHOW STRONG VERTICAL SHEAR PROFILES
SUGGESTING SUPERCELL DEVELOPMENT WILL BE POSSIBLE. SUPERCELLS WILL
BECOME INCREASINGLY LIKELY AS MODERATE INSTABILITY DEVELOPS ACROSS
ERN KS EARLY THIS EVENING. TORNADOES AND VERY LARGE HAIL WILL BE
POSSIBLE WITH SUPERCELLS. HOWEVER...A POTENTIAL FOR WIND DAMAGE WILL
ALSO BE POSSIBLE ESPECIALLY IF THE STORMS CAN ORGANIZE INTO A BOWING
LINE-SEGMENT MOVING INTO WRN MO DURING THE LATE EVENING.

..BROYLES/STOPPKOTTE.. 05/10/2010