Moderate Risk!

...CNTRL/NRN GREAT PLAINS... AS THE STRONG PACIFIC FRONT SURGES EAST ACROSS THE HIGH PLAINS LATER TODAY IT APPEARS THAT IT WILL PROBABLY OVERTAKE DRYLINE FORMATION ACROSS PARTS OF NRN KS/SRN NEB. A WEAK QUASI-STATIONARY BOUNDARY ALONG THE KS/NEB BORDER MAY ACT AS A WARM FRONT WHERE STRONGER FORCING AND SHEAR CAN DEVELOP NEAR THE INTERSECTION WITH THE COLD FRONT. TRUE WARM FRONT WITH LARGER SCALE SYSTEM IS HARDER TO DEFINE BASED ON RAPID INTENSIFICATION AND EXTENSIVE NATURE OF THE LOW LEVEL SLY FLOW DEVELOPING ACROSS THE PLAINS...AND LIMITED N-S AIR MASS DISCONTINUITY. HOWEVER...A SECONDARY AREA OF ENHANCED FORCING WILL LIKELY OCCUR NEAR AND SE OF THE CENTER OF THE OCCLUDING SURFACE LOW...FROM EXTREME ERN WY/MT ACROSS WRN PARTS OF SD/NEB LATER THIS AFTERNOON THROUGH THIS EVENING. SURFACE DEWPOINTS ARE FORECAST TO RANGE FROM THE 50S NORTH TO LOWER 60S ACROSS NCNTRL KS. SLIGHTLY COOLER TEMPERATURES ALOFT ACROSS NRN PARTS OF THE PLAINS WILL OFFSET MORE LIMITED MOISTURE. A FAIRLY UNIFORM PLUME OF SURFACE-BASED DESTABILIZATION /MLCAPE 1000-1500 J PER KG/ IS EXPECTED TO DEVELOP IN ADVANCE OF THE COLD FRONT FROM SWRN SD TO NRN KS BY LATE AFTERNOON. GIVEN MAGNITUDE OF LARGE SCALE FORCING FOCUSED ALONG THE FRONT...AND ENHANCED MESOSCALE FORCING NEAR AFOREMENTIONED FEATURES...RAPID TSTM DEVELOPMENT IS INDICATED IN ALL AVAILABLE GUIDANCE BY ABOUT 21Z. AMBIENT DEEP-LAYER SHEAR WILL SUPPORT RAPIDLY MOVING STORMS WITH PERSISTENT/ORGANIZED UPDRAFTS CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WINDS...AND POSSIBLY A COUPLE OF STRONG TORNADOES. INCREASING MERIDIONAL COMPONENT OF MEAN WIND AND DEEP-LAYER SHEAR VECTORS ORIENTED ALONG THE LINE OF FRONTAL FORCING SUGGEST THAT CONVECTION MAY EVOLVE RATHER RAPIDLY INTO QLCS WITH BOWING LINE SEGMENTS MOVING AT AROUND 50KT SPREADING DAMAGING WINDS EWD/NEWD ACROSS CNTRL NEB AND NCNTRL KS THROUGH THE NIGHT. CONVECTION WILL ALSO DEVELOP EWD INTO STRONGLY BACKED SURFACE FLOW WHERE EFFECTIVE SRH AROUND 300 M2/S2 WILL PROVIDE MORE THAN AN ADEQUATE ENVIRONMENT FOR A COUPLE OF POTENTIALLY STRONG TORNADOES. GREATER TORNADIC POTENTIAL WILL OCCUR WITH ANY DISCRETE CELLS...OR LINE BREAKS...IN PROXIMITY TO BOUNDARY INTERSECTIONS AND OTHER MESOSCALE FEATURES WHERE STORM SCALE INFLOW/DYNAMICS WILL BE LOCALLY ENHANCED.

...SRN GREAT PLAINS... FARTHER SOUTH...SEPARATION BETWEEN DRYLINE AND COLD FRONT MAY BE GREATER FROM SWRN KS ACROSS OK/TX. SITUATION APPEARS FAVORABLE FOR DRYLINE SUPERCELL INITIATION ACROSS THESE AREAS PRIOR TO COLD FRONT ADVANCING EAST AND MERGING WITH THE DRYLINE...MOST LIKELY AFTER DARK. HERE TOO...ENVIRONMENT APPEARS VERY SUPPORTIVE OF MYRIAD OF SEVERE WEATHER THREATS AS EFFECTIVE BULK SHEAR INCREASES TO OVER 40KT ACROSS STRONGLY UNSTABLE AIR MASS CHARACTERIZED BY MLCAPE OF AT LEAST 2000 J/KG. OTHER THAN CONFLUENCE ZONE NEAR THE DRYLINE...LACK OF STRONGLY DEFINED MESOSCALE BOUNDARIES IN THE WARM SECTOR SUGGEST CELLS MAY REMAIN DISCRETE IN NATURE AS EFFECTIVE SRH LOCALLY INCREASES TO OVER 300 M2/S2 THROUGH 00Z. SPC ANALOG SOUNDING SYSTEM REVEALS A FEW SIGNIFICANT TORNADO MATCHES BASED ON NAM-WRF FORECAST SOUNDINGS FROM NWRN TX/WRN OK VALID AROUND 00Z. PRESENT INDICATIONS BASED ON A VARIETY OF MODEL GUIDANCE SUGGEST MOST SUPPORTIVE ENVIRONMENT FOR A STRONG TORNADO OR TWO MAY EVOLVE IN A RELATIVELY NARROW CORRIDOR FROM NWRN TX TO SWRN KS THROUGH EARLY EVENING. PROXIMITY TO GREATER LOW LEVEL MOISTURE ACROSS SRN PARTS OF THIS AREA COULD SUPPORT A COUPLE OF LONGER-TRACK DANGEROUS STORMS. ADDITIONALLY...SPC HAIL MODEL BASED ON NAM-WRF INPUT SOUNDINGS GENERATES HAILSTONE DIAMETERS OF 1-3 INCHES ACROSS MUCH OF THE SRN PLAINS AREA WHERE STORM INITIATION IS ANTICIPATED LATER THIS AFTERNOON.