The risk for severe weather on Saturday is increasing. The SPC has increased the probability of severe weather to a HIGH risk for Saturday for portions of Oklahoma, Kansas and Texas. This is a good thing for storm chasers, but the outlook isn’t good for residents. Saturday is shaping up to be a major event — a tornado outbreak. A life threatening situation is developing.
I hope the models are wrong, but residents in Oklahoma, Texas and Kansas should take today to prepare for the potential of a weather emergecy. Make certain your storm shelters and shelter-in-place areas are ready, your emergency surivial kits are stocked, and weather radios have fresh batteries in them.
NWS STORM PREDICTION CENTER NORMAN OK
0102 AM CDT FRI APR 13 2012
VALID 141200Z – 151200Z
…THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF OK AND KS…
…THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NW TX…CNTRL
AND WRN OK…CNTRL AND ERN KS…SE NEB…NW MO AND FAR SW IA…
…THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID-MO
VALLEY…UPPER MS VALLEY…SRN PLAINS AND CNTRL PLAINS…
TORNADO OUTBREAK LIKELY ACROSS THE SRN AND CNTRL PLAINS NWD INTO THE MID-MO VALLEY FROM SATURDAY AFTERNOON THROUGH SATURDAY NIGHT
…SRN AND CNTRL PLAINS…
AN IMPRESSIVE UPPER-LEVEL LOW WILL MOVE EWD ACROSS FOUR CORNERS
REGION SATURDAY AS A POWERFUL 90 TO 110 KT MID-LEVEL JET EJECTS NEWD INTO THE SRN AND CNTRL PLAINS. AHEAD OF THE SYSTEM…A CORRIDOR OF MODERATE TO STRONG INSTABILITY IS FORECAST ACROSS ECNTRL KS…CNTRL OK INTO NW TX. THIS COMBINED WITH STEEP MID-LEVEL LAPSE RATES AND STRONG LOW-LEVEL SHEAR WILL BE VERY FAVORABLE FOR SEVERE STORMS AND A TORNADO OUTBREAK WILL BE LIKELY ACROSS THE SRN AND CNTRL PLAINS FROM LATE SATURDAY AFTERNOON LASTING THROUGH THE EVENING AND INTO THE OVERNIGHT PERIOD.
NAM AND NAMKF FORECAST SOUNDINGS AT 00Z SATURDAY EVENING FROM SALINA KS SWD TO AROUND OKLAHOMA CITY SHOW MLCAPE VALUES FROM 2000 TO 3000 J/KG WITH 0-6 KM SHEAR IN THE 60 TO 75 KT RANGE. IN ADDITION…HODOGRAPHS ARE LARGE AND LOOPED WITH 0-1 KM SHEAR VALUES IN THE 30 TO 40 KT RANGE. THIS ENVIRONMENT SHOULD BE VERY FAVORABLE FOR SUPERCELLS AND TORNADOES. 0-3 KM STORM RELATIVE HELICITIES ARE FORECAST TO BE AROUND 400 M2/S2 WHICH IS IDEAL FOR STRONG TORNADOES AND A TORNADO OUTBREAK APPEARS LIKELY. THE GREATEST THREAT FOR SIGNIFICANT TORNADOES SHOULD EXIST SATURDAY EVENING FROM SALINA SWD TO OKLAHOMA CITY. 700 TO 500 MB LAPSE RATES AROUND 7.5 C/KM WILL ALSO BE FAVORABLE FOR LARGE HAIL AND HAIL GREATER THAN 2 INCHES WILL BE POSSIBLE THE MORE INTENSE SUPERCELLS. A WIND DAMAGE THREAT WILL ALSO EXIST DUE TO THE EXPECTED INTENSE NATURE OF THE STORMS.
THE MAIN CONCERN FOR THIS FORECAST IS CONVECTIVE COVERAGE. MANY OF THE MODELS DO NOT DEVELOP NUMEROUS THUNDERSTORMS ALONG THE DRYLINE.
IN SPITE OF THIS…THE MODELS DIMINISH THE CAP ACROSS THE SRN AND CNTRL PLAINS LATE SATURDAY AFTERNOON SO THIS BRINGS THE MODELS INTO QUESTION. IN ADDITION…THE MODELS DRIVE A BAND OF LARGE-SCALE ASCENT ACROSS CNTRL KS DURING THE EARLY EVENING SUGGESTING MANY STORMS SHOULD INITIATE WITH STORMS INITIATING SWD WITH TIME EARLY SATURDAY EVENING AS THE LOW-LEVEL JET STRENGTHENS. THESE FACTORS COMBINED WITH SFC DEWPOINTS IN THE LOWER TO MID 60S F AND VERY FAVORABLE LOW-LEVEL SHEAR PROFILES SHOULD PRODUCE AND ENVIRONMENT FAVORABLE FOR A TORNADO OUTBREAK. AFTER COLLABORATION WITH WFOS WICHITA…NORMAN…TOPEKA…TULSA AND DODGE CITY…A HIGH RISK WILL BE ISSUED DUE TO THE POTENTIAL FOR A HIGH-END LIFE THREATENING EVENT ACROSS THE SRN AND CNTRL PLAINS.
…MID-MO VALLEY/UPPER MS VALLEY…
AN IMPRESSIVE UPPER-LEVEL LOW WILL MOVE ACROSS THE FOUR CORNERS REGION SATURDAY. AT THE SFC…A LOW SHOULD MOVE ACROSS NEB WITH A WARM FRONT EXTENDING EWD ACROSS IA. THUNDERSTORMS SHOULD BE ONGOING ALONG THIS BOUNDARY WITH STORMS EXPANDING NWD INTO THE UPPER MS VALLEY. SOUTH OF THE BOUNDARY…THE MODELS DEVELOP MODERATE INSTABILITY WITH A DRYLINE LOCATED IN ECNTRL NEB. THUNDERSTORMS THAT INITIATE ALONG THE DRYLINE AND EWD ACROSS THE WARM SECTOR WILL LIKELY HAVE AN ENHANCED SEVERE THREAT. STRONG DEEP LAYER SHEAR AND ENHANCED LOW-LEVEL SHEAR WILL BE FAVORABLE FOR SUPERCELLS AND TORNADOES. A FEW STRONG TORNADOES MAY OCCUR WITH THE MORE DOMINANT SUPERCELLS ESPECIALLY AS THE LOW-LEVEL JET STRENGTHENS SATURDAY EVENING. ALTHOUGH A TORNADO OUTBREAK WILL BE POSSIBLE ACROSS PARTS OF THE REGION…THE GREATEST MOISTURE RETURN SHOULD REMAIN FURTHER TO THE SOUTH SUGGESTING THE HIGHEST TORNADO THREAT SHOULD EXIST ACROSS SERN NEB…SW IA…NW MO AND ERN KS WHERE A MODERATE RISK IS LOCATED.
…NW TX/WCNTRL TX…
AN IMPRESSIVE UPPER-LEVEL LOW WILL MOVE EWD ACROSS THE FOUR CORNERS REGION AND INTO THE HIGH PLAINS SATURDAY EVENING. MODEL FORECASTS DEVELOP THUNDERSTORMS ALONG A WELL-DEFINED DRYLINE DURING THE EVENING FROM WRN OK SSWWD ACROSS NW TX INTO WCNTRL TX. FORECAST SOUNDINGS SATURDAY EVENING ALONG THIS CORRIDOR SHOW MODERATE INSTABILITY…STRONG DEEP LAYER SHEAR AND STEEP MID-LEVEL LAPSE RATES WHICH SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. SUPERCELLS SHOULD BE CAPABLE OF PRODUCING 2 INCH OR GREATER HAIL DUE TO THE THERMODYNAMIC PROFILE. STRENGTHENING LOW-LEVEL SHEAR DURING THE EVENING SHOULD ALSO RESULT IN A TORNADO THREAT AS WELL.