MD 1000 CONCERNING SEVERE THUNDERSTORM WATCH 289… FOR PORTIONS OF S-CNTRL/SERN NEB…SWRN IA…FAR NWRN MO…N-CNTRL/NERN KS
MESOSCALE DISCUSSION 1000 NWS STORM PREDICTION CENTER NORMAN OK 0539 PM CDT SAT JUN 08 2013 AREAS AFFECTED...PORTIONS OF S-CNTRL/SERN NEB...SWRN IA...FAR NWRN MO...N-CNTRL/NERN KS CONCERNING...SEVERE THUNDERSTORM WATCH 289... VALID 082239Z - 090015Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 289 CONTINUES. SUMMARY...THE THREAT FOR SVR STORMS CONTINUES ACROSS SEVERE THUNDERSTORM WATCH 289. DISCUSSION...DURING THE NEXT COUPLE OF HOURS...THE AREA OF GREATEST CONCERN FOR STRONG/SVR WIND GUSTS AND SVR HAIL WILL EXTEND ACROSS THAT PART OF WW 289 IN NERN KS IN ASSOCIATION WITH A SQUALL LINE MOVING ACROSS SRN PARTS OF THE WW AREA. MODIFIED FORECAST SOUNDINGS TO ACCOUNT FOR CURRENT SFC OBSERVATIONS INDICATE MLCAPE VALUES OF AROUND 500-1000 J/KG IN ADVANCE OF THIS LINE. AND...WITH AT LEAST MODEST INFLOW COMBINED WITH AROUND 30 KT OF 0-6-KM BULK SHEAR PER TWX VWP DATA SUGGESTS THAT THE SQUALL LINE WILL LIKELY BE MAINTAINED EWD ACROSS PORTIONS OF NERN KS. DMGG WIND GUSTS WILL BE POSSIBLE WITH THIS ACTIVITY...PARTICULARLY WITH ANY EMBEDDED BOWING SEGMENTS/LEWP STRUCTURES...AND SVR HAIL WILL ALSO BE POSSIBLE. CONVECTIVE OVERTURNING ACCOMPANYING THIS SQUALL LINE WILL ALLOW THE SVR THREAT TO END FOLLOWING ITS PASSAGE. FARTHER N ACROSS THE WW AREA...MIXED CONVECTIVE MODES ARE BEING OBSERVED AHEAD OF COLD AND OCCLUDED FRONTAL SEGMENTS PER RADAR IMAGERY. SCATTERED STORM CLUSTERS AND SMALL QUASI-LINEAR CONVECTIVE SEGMENTS ARE BECOMING SLIGHTLY BETTER ORGANIZED...AS FORCING FOR ASCENT IN THE EXIT REGION OF A MID-LEVEL JET MAX OVERSPREADS THE AREA PER RECENT WATER VAPOR IMAGERY. RELATIVELY MORE BACKED SFC WINDS IN CLOSER PROXIMITY TO A STATIONARY FROM THAT EXTENDS FROM A TRIPLE POINT 20 WSW OLU TO THE NEB/IA BORDER 20 S OMA AND INTO FAR SWRN IA MAY SUPPORT WEAK STORM-SCALE CIRCULATIONS. OAX VWP DATA INDICATE A LONG LOOPING HODOGRAPH IN THE LOW LEVELS...SUPPORTING 0-1-KM SRH AROUND 300-350 M2/S2. HOWEVER...BUOYANCY IS...AND SHALL REMAIN...VERY WEAK AS HIGHER CONVECTIVE COVERAGE AND WIDESPREAD CLOUDS KEEP THE BOUNDARY LAYER RELATIVELY COOL -- I.E. SFC TEMPERATURES IN THE UPPER 60S TO THE MIDDLE 70S. MARGINALLY SVR HAIL WILL BE THE MAIN CONCERN WITH THIS ACTIVITY...AND STRONG WIND GUSTS WILL BE POSSIBLE IF BOWING SEGMENTS CAN BE SUPPORTED NEAR/S OF THE STATIONARY FRONT. A WEAK/BRIEF TORNADO CANNOT BE COMPLETELY RULED OUT OVER PARTS OF SERN NEB...FAR NWRN MO...AND FAR SWRN IA...THOUGH THIS THREAT IS EXPECTED TO REMAIN TOO LIMITED FOR ANY WW UPGRADES. ..COHEN.. 06/08/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DMX...EAX...OAX...TOP...ICT...GID... LAT...LON 39139594 39139893 41769805 41769496 39139594
via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1000.html
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