RiskArea (sq. mi.)Area Pop.Some Larger Population
Centers in Risk Area
MODERATE119,9879,218,833Memphis, TN...Kansas City, MO...Shreveport, LA...Little Rock, AR...Overland Park, KS
...SLIGHT343,75227,689,207Dallas, TX...Ft. Worth, TX...Omaha, NE...Tulsa, OK...Wichita, KS...
Forecast Discussion
SPC AC 271251 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0751 AM CDT SUN APR 27 2014 VALID 271300Z - 281200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER FAR ERN PARTS OF KS/OK...NERN TX...AR...WRN/CNTRL/SRN MO...NWRN MS AND WRN TN... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VALLEY TO ERN TX AND THE LOWER MS VALLEY... ...SUMMARY... WIDESPREAD SEVERE THUNDERSTORMS CAPABLE OF TORNADOES...VERY LARGE HAIL AND DAMAGING WINDS ARE LIKELY FROM THE MIDDLE AND LOWER MISSOURI VALLEY SOUTH THROUGH THE OZARKS INTO LOWER MISSISSIPPI VALLEY THIS AFTERNOON INTO TONIGHT. THE GREATEST RISK FOR A FEW INTENSE TORNADOES WILL EXIST ACROSS MUCH OF ARKANSAS PERHAPS INTO WESTERN AND CENTRAL MISSOURI THIS AFTERNOON INTO TONIGHT. ...SYNOPSIS... A POWERFUL SHORT-WAVE TROUGH AND ASSOCIATED 70-80 KT MIDLEVEL JET STREAK WILL TRANSLATE FROM THE CNTRL/SRN HIGH PLAINS INTO THE UPPER MIDWEST WITH THE SYSTEM CLOSING OFF AN UPPER LOW OVER THE CNTRL PLAINS. ON THE HEELS OF THE INITIAL SHORT-WAVE TROUGH...A CHANNELED VORTICITY MAXIMUM AND ATTENDANT 70+ KT JET STREAK AT 500 MB WILL PROGRESS THROUGH THE SRN PLAINS INTO THE OZARK PLATEAU BY TONIGHT. IN RESPONSE TO THIS UPPER-AIR PATTERN EVOLUTION...A 40-50+ KT SLY LLJ WILL MIGRATE FROM ERN PARTS OF THE GREAT PLAINS INTO MS VALLEY...ENHANCING THE POLEWARD FLUX OF HEAT AND MOISTURE THROUGH THE WARM SECTOR OF THE SYNOPTIC CYCLONE. AT THE SURFACE...A LEE CYCLONE OVER SWRN NEB WILL GRADUALLY FILL AS IT SLOWLY DEVELOPS ENEWD INTO ERN NEB BY 28/12Z. A TRAILING PACIFIC FRONT WILL SURGE EWD THROUGH THE CNTRL PLAINS INTO OZARKS/OZARK PLATEAU WITH THE SRN EXTENSION OF THE FRONT MOVING MORE SLOWLY EWD THROUGH CNTRL INTO ERN TX. MEANWHILE...A WARM FRONT WILL STEADILY MOVE NWD THROUGH THE LOWER/MID MO AND MID MS VALLEYS. ...SRN PLAINS INTO THE LOWER MS VALLEY THIS MORNING THROUGH TONIGHT... TSTMS HAVE RECENTLY DEVELOPED ALONG AND JUST AHEAD OF THE PACIFIC FRONT OVER OK/N TX ALONG THE SRN FRINGE OF STRONGER HEIGHT FALLS/DCVA ATTENDANT TO THE SHORT-WAVE PROGRESSING NEWD INTO THE CNTRL PLAINS. THESE STORMS ARE LIKELY SLIGHTLY ELEVATED AND ROOTED WITHIN A MOIST WARM CONVEYOR BELT AIR STREAM WHICH COINCIDES WITH STEEP MIDLEVEL LAPSES AND MUCAPE OF 2000-2500 J/KG. AREA VAD DATA INDICATE A VEER-BACK SIGNATURE WITH HEIGHT WHICH SHOULD YIELD COMPLEX STORM MODES CAPABLE OF MAINLY LARGE HAIL AND LOCALLY DAMAGING WINDS AS ACTIVITY SHIFTS NEWD THIS MORNING. A SUBSET OF THE ONGOING STORMS WILL LIKELY BECOME SURFACE-BASED BY LATE MORNING INTO AFTERNOON OVER ERN OK INTO NERN TX WITH OTHER IN SITU STORM DEVELOPMENT ALONG THE FRONT. ADDITIONAL TSTMS ARE ANTICIPATED BY AFTERNOON AHEAD OF THE FRONT FROM THE ARKLATEX NEWD ACROSS AR...IN THE WAKE OF THE MORNING ELEVATED STORMS. BOTH THESE REGIMES WILL BE ENCOURAGED BY THE ARRIVAL OF THE NEXT MIDLEVEL JET STREAK PROPAGATING THROUGH THE RED RIVER VALLEY. THE COMBINATION OF MODERATE INSTABILITY AND RELATIVELY STRONG VERTICAL SHEAR WILL PROMOTE A MIXTURE OF SUPERCELL AND BOWING STRUCTURES CAPABLE OF TORNADOES...VERY LARGE HAIL AND DAMAGING WINDS. THE MOST FAVORABLE ENVIRONMENT FOR LONG-LIVED SUPERCELLS AND MULTIPLE INTENSE TORNADOES WILL LIKELY MATERIALIZE OVER AR TOWARD THE DELTA REGION OF NWRN MS LATER THIS AFTERNOON INTO TONIGHT. HERE...MLCAPE OF 2000-2500 J/KG WILL ALIGN WITH EFFECTIVE SRH OF 250-350 M2/S2 AND 50-60 KT OF DEEP-LAYER SHEAR TO CREATE A VERY FAVORABLE ENVIRONMENT FOR UPDRAFT ROTATION. AN UPGRADE TO A CATEGORICAL HIGH RISK REMAINS POSSIBLE OVER THIS AREA LATER TODAY. ...NEB/KS EWD INTO MID MS VALLEY LATE THIS MORNING INTO TONIGHT... ELEVATED TSTMS HAVE GRADUALLY INCREASED IN COVERAGE EARLY THIS MORNING OVER THE CNTRL PLAINS ALONG THE LEADING EDGE OF HEIGHT FALLS ATTENDANT TO THE HIGH PLAINS SHORT-WAVE TROUGH...AND ROOTED WITHIN A BELT OF ISENTROPIC ASCENT ALONG THE NOCTURNAL LLJ. THIS ACTIVITY MAY CONTINUE TO INCREASE IN AREAL COVERAGE THIS MORNING WHILE MOVING NEWD INTO THE MID AND LOWER MO VALLEY. LARGE HAIL AND LOCALLY DAMAGING WIND GUSTS WILL BE THE PRIMARY HAZARDS WITH THESE STORMS. UNCERTAINTY IN DEGREE OF AFTERNOON DESTABILIZATION HAS INCREASED OVER THE LAST COUPLE OF HOURS OWING TO THE GROWING EXTENT OF ELEVATED TSTMS. WHERE BREAKS IN THE CLOUDS CAN OCCUR...CONTINUED BOUNDARY LAYER MOISTENING COUPLED WITH STRONG COOLING ALOFT WILL PROMOTE MLCAPE APPROACHING 1000-2000 J/KG. WHEN COUPLED WITH VERTICALLY VEERING WIND PROFILES AND 40-50 KT OF DEEP-LAYER SHEAR...THE ENVIRONMENT WILL BE SUPPORTIVE OF A MIXTURE OF BOWING AND SUPERCELL STRUCTURES CAPABLE OF TORNADOES /SOME POSSIBLY STRONG/...VERY LARGE HAIL AND DAMAGING WINDS. THE POTENTIAL FOR ISOLATED TORNADOES WILL EXIST AS FAR W/SW AS WRN NEB/NERN CO/NWRN KS INVOF THE DEEP-LAYER CYCLONE WHERE STEEP LAPSE RATES WILL COINCIDE WITH HIGH AMBIENT VERTICAL VORTICITY. BY THIS EVENING INTO TONIGHT...TSTMS MAY CONSOLIDATE INTO CLUSTERS OR A QLCS WITH THE RISK FOR PRIMARILY DAMAGING WINDS AND HAIL SPREADING EWD INTO THE MID MS VALLEY. ..MEAD/MOSIER.. 04/27/2014 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z CURRENT UTC TIME: 1318Z (8:18AM), RELOAD THIS PAGE TO UPDATE THE TIME