MESOSCALE DISCUSSION 0369 NWS STORM PREDICTION CENTER NORMAN OK 0203 AM CDT THU MAR 29 2007 AREAS AFFECTED...SRN KS...WRN OK...NW TX CONCERNING...TORNADO WATCH 87... VALID 290703Z - 290800Z A CONVECTIVE LINE CURRENTLY EXTENDS SWD FROM EAST OF DODGE CITY KS TO NEAR CHILDRESS TX. THIS LINE WILL CONTINUE EWD OVERNIGHT AND SHOULD GRADUALLY BECOME WEAKER WITH TIME. ISOLATED WIND DAMAGE AND MARGINALLY SEVERE HAIL WILL REMAIN POSSIBLE WITH THE STRONGER CELLS IN THE LINE. ALTHOUGH WW ISSUANCE REMAINS POSSIBLE...A WW IS NOT ANTICIPATED ACROSS THE REGION ATTM. THE LATEST SFC MAP SHOWS A SFC LOW OVER THE OK PANHANDLE WITH A MOIST AXIS EXTENDING NWD FROM NW TX ACROSS WRN OK WHERE DEWPOINTS ARE IN THE LOWER 60S F. ALTHOUGH THE AIRMASS AHEAD OF THE LINE SHOULD SUPPORT THE MCS...THE STRONGEST LARGE-SCALE ASCENT WITH THE UPPER-LOW SHOULD REMAIN FURTHER WEST. THIS ALONG WITH COOLING IN THE BOUNDARY LAYER SHOULD ALLOW THE CONVECTIVE LINE TO DECREASE IN INTENSITY OVER THE NEXT FEW HOURS. AN ISOLATED WIND DAMAGE THREAT AND MARGINALLY SEVERE HAIL SHOULD PERSIST DUE TO THE STRONG SHEAR AND STEEP LAPSE RATES IN PLACE. HOWEVER...REPORT COVERAGE SHOULD BECOME INCREASINGLY ISOLATED LATE TONIGHT. ..BROYLES.. 03/29/2007 MESOSCALE DISCUSSION 0368 NWS STORM PREDICTION CENTER NORMAN OK 1107 PM CDT WED MAR 28 2007 AREAS AFFECTED...S CENTRAL SD/WRN AND CENTRAL NEB/WRN KS CONCERNING...TORNADO WATCH 83...86... VALID 290407Z - 290600Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 83...86...CONTINUES. THOUGH A FEW ISOLATED SUPERCELLS CONTINUE -- PARTICULARLY ACROSS PARTS OF SWRN KS WHERE STORMS CONTINUE SPREADING NNEWD OUT OF NWRN OK...STORM MODE CONTINUES TO EVOLVE TOWARD A MORE LINEAR CONFIGURATION -- INCLUDING SEVERAL BOWS/LEWPS -- ALONG COLD FRONT. ALONG WITH THREAT FOR LARGE HAIL...DEGREE OF SHEAR CONTINUES TO SUPPORT A THREAT FOR TORNADOES IN AND NEAR WW AREAS. IN ADDITION...LOCAL WIND DAMAGE THREAT MAY ALSO INCREASE OVER THE NEXT COUPLE OF HOURS AS STORMS PERSIST/SHIFT SLOWLY EWD WITHIN MODERATELY-UNSTABLE ENVIRONMENT. WITH WW 83 SET TO EXPIRE AT 29/05Z AND SEVERE THREAT LIKELY TO PERSIST BEYOND THIS TIME...NEW WW WILL LIKELY BE REQUIRED. ..GOSS.. 03/29/2007 MESOSCALE DISCUSSION 0367 NWS STORM PREDICTION CENTER NORMAN OK 1058 PM CDT WED MAR 28 2007 AREAS AFFECTED...ERN HALVES OF THE TX/OK PANHANDLES AND WRN OK SWD INTO THE TX TRANSPECOS REGION CONCERNING...TORNADO WATCH 82...84...85... VALID 290358Z - 290500Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 82...84...85...CONTINUES. THOUGH A FEW ISOLATED SUPERCELLS CONTINUE...PRIMARY STORM MODE IS TRANSITIONING TOWARD A COMPLEX LINE -- EXTENDING FROM NEAR AMA SSWWD INTO FAR SERN NM...AS COLD FRONT OVERTAKES THE DRYLINE. DESPITE THIS SLOW TRANSITION IN STORM MODE...FAVORABLE SHEAR PERSISTS AS DEPICTED BY LATEST AREA VAD/PROFILER DATA. THEREFORE...THREAT FOR AT LEAST ISOLATED TORNADOES CONTINUES...ALONG WITH HAIL AND AN INCREASING POTENTIAL FOR LOCALLY-DAMAGING WINDS. WITH WW 82 AND 84 SET TO EXPIRE AT 29/05Z...NEW WW WILL LIKELY BE ISSUED REPLACING THESE TWO WATCHES SHORTLY. ..GOSS.. 03/29/2007 MESOSCALE DISCUSSION 0366 NWS STORM PREDICTION CENTER NORMAN OK 0920 PM CDT WED MAR 28 2007 AREAS AFFECTED...SWRN SD...WRN NEB...FAR ERN CO...WRN KS CONCERNING...TORNADO WATCH 81...83... VALID 290220Z - 290400Z CORRECTED TO CHANGE WRN SC TO WRN SD THE SEVERE WEATHER THREAT FOR TORNADO WATCH 81...83...CONTINUES. EXTENSIVE AREA OF SEVERE/SUPERCELL STORMS EXTENDS SWD ACROSS THE HIGH PLAINS FROM WRN SD SWD INTO TX -- INCLUDING AREAS IN AND NEAR WW 81 AND 83. ALONG WITH LARGE HAIL AND DAMAGING WIND THREAT...NUMEROUS REPORTS OF TORNADOES HAVE BEEN RECEIVED OVER THE PAST COUPLE OF HOURS ACROSS WRN NEB/WRN KS. WITH 40 KT SELY LOW-LEVEL JET OBSERVED ACROSS THE HIGH PLAINS...EXPECT STORMS TO CONTINUE TO INCREASE IN COVERAGE. MODERATELY-UNSTABLE AIRMASS /MEAN-LAYER CAPE 1000 TO 2000 J/KG/ COMBINED WITH STRONG/VEERING FLOW WITH HEIGHT SUGGESTS THAT SEVERE/TORNADO THREAT WILL LIKEWISE CONTINUE. WITH WW 81 SET TO EXPIRE AT 29/03Z...A NEW WW WILL BE REQUIRED ACROSS PARTS OF SWRN SD INTO WRN NEB. ..GOSS.. 03/29/2007 MESOSCALE DISCUSSION 0366 NWS STORM PREDICTION CENTER NORMAN OK 0906 PM CDT WED MAR 28 2007 AREAS AFFECTED...SWRN SD///WRN NEB...FAR ERN CO...WRN KS CONCERNING...TORNADO WATCH 81...83... VALID 290206Z - 290400Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 81...83...CONTINUES. EXTENSIVE AREA OF SEVERE/SUPERCELL STORMS EXTENDS SWD ACROSS THE HIGH PLAINS FROM WRN SC SWD INTO TX -- INCLUDING AREAS IN AND NEAR WW 81 AND 83. ALONG WITH LARGE HAIL AND DAMAGING WIND THREAT...NUMEROUS REPORTS OF TORNADOES HAVE BEEN RECEIVED OVER THE PAST COUPLE OF HOURS ACROSS WRN NEB/WRN KS. WITH 40 KT SELY LOW-LEVEL JET OBSERVED ACROSS THE HIGH PLAINS...EXPECT STORMS TO CONTINUE TO INCREASE IN COVERAGE. MODERATELY-UNSTABLE AIRMASS /MEAN-LAYER CAPE 1000 TO 2000 J/KG/ COMBINED WITH STRONG/VEERING FLOW WITH HEIGHT SUGGESTS THAT SEVERE/TORNADO THREAT WILL LIKEWISE CONTINUE. WITH WW 81 SET TO EXPIRE AT 29/03Z...A NEW WW WILL BE REQUIRED ACROSS PARTS OF SWRN SD INTO WRN NEB. ..GOSS.. 03/29/2007 MESOSCALE DISCUSSION 0365 NWS STORM PREDICTION CENTER NORMAN OK 0852 PM CDT WED MAR 28 2007 AREAS AFFECTED...TX/OK PANHANDLES INTO WRN OK...WRN N TX...AND THE TX SOUTH PLAINS CONCERNING...TORNADO WATCH 82...84... VALID 290152Z - 290345Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 82...84...CONTINUES. SIGNIFICANT SEVERE WEATHER EVENT ONGOING ATTM...WITH MOST DANGEROUS STORMS -- A CLUSTER OF SUPERCELLS -- NOW OVER THE E CENTRAL TX PANHANDLE. THUS FAR...STORMS HAVE REMAINED W OF THE TX/OK LINE -- W OF WW 84. HOWEVER...THREAT MAY SPREAD EWD INTO FAR WRN OK IN THE NEXT 1-2 HOURS. MEANWHILE...LINEAR CONVECTION IS DEVELOPING ATTM FROM THE CENTRAL TX PANHANDLE SWWD INTO FAR SERN NM ALONG THE DRYLINE. WITH 1500 TO 2000 J/KG MEAN-LAYER CAPE PERSISTING ACROSS THIS REGION ALONG WITH VERY FAVORABLE SHEAR PROFILES...EXPECT SEVERE THREAT TO PERSIST ACROSS THIS REGION FOR THE NEXT SEVERAL HOURS AS STORMS CONTINUE TO INCREASE IN COVERAGE. ..GOSS.. 03/29/2007 MESOSCALE DISCUSSION 0364 NWS STORM PREDICTION CENTER NORMAN OK 0708 PM CDT WED MAR 28 2007 AREAS AFFECTED...TX/OK PANHANDLES CONCERNING...TORNADO WATCH 82... VALID 290008Z - 290215Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 82 CONTINUES. ISOLATED SUPERCELLS -- INCLUDING TWO STORMS EXHIBITING STRONG ROTATION OVER SERN ARMSTRONG/SWRN DONLEY COUNTIES AND NERN BRISCOE/NWRN HALL COUNTIES...AND A NWD-MOVING LEFT-SPLIT NOW OVER HUTCHINSON CO -- CONTINUE MOVING ACROSS THE TX PANHANDLE ATTM. REPORTS OF HAIL UP TO SOFTBALL SIZE AND SPORADIC TORNADO TOUCHDOWNS HAVE BEEN RECEIVED IN THE PAST 1-2 HOURS. WITH 1500 TO 2500 J/KG MEAN-LAYER CAPE NOW INDICATED OVER THIS REGION PER LATEST OBJECTIVE ANALYSES AND CURRENT AMARILLO TX WSR-88D VWP INDICATING 29 KT SFC-1 KM SHEAR AND 275 M2/S2 SFC-1 KM HELICITY...THREAT FOR LOW-LEVEL MESOCYCLONES/TORNADOES WILL CONTINUE. ..GOSS.. 03/29/2007 MESOSCALE DISCUSSION 0361 NWS STORM PREDICTION CENTER NORMAN OK 0329 PM CDT WED MAR 28 2007 AREAS AFFECTED...WRN KS...FAR SWRN NEB AND EXTREME ERN CO CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 282029Z - 282200Z TORNADO WATCH WILL BE NEEDED SHORTLY FOR MOST OF WRN KS AND SURROUNDING AREAS. VISIBLE SATELLITE IMAGERY INDICATES CU INCREASING IN DEEPLY MIXED/DRY AIR ACROSS ERN CO...WITH ADDITIONAL CU FARTHER E INTO WRN KS. NW-SE ORIENTED CLOUD BILLOWS ALSO INDICATE CAPPING IN PLACE OVER MUCH OF NEB INTO KS. MODIFIED 18Z DDC SOUNDING SHOWS LITTLE CIN REMAINS ALONG AND W OF THAT LONGITUDE WITH STEEP MID/UPPER LAPSE RATES IN PLACE WITH VERY STRONG SHEAR PROFILES. CONTINUED PRESSURE FALLS W OF DRYLINE WILL KEEP LOW LEVEL FLOW BACKED WITH INCREASING SFC DEWPOINTS. SUPERCELLS ARE LIKELY TO FORM ALONG THE CO/KS BORDER REGION WITH VERY LARGE HAIL AND TORNADOES LIKELY. A FEW TORNADOES MAY BE STRONG. ..JEWELL.. 03/28/2007