SPC MD 491

MD 0491 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR ERN KS INTO WRN/CENTRAL MO


MESOSCALE DISCUSSION 0491
NWS STORM PREDICTION CENTER NORMAN OK
0950 AM CDT WED APR 17 2013

AREAS AFFECTED...ERN KS INTO WRN/CENTRAL MO

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171450Z - 171545Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...A SEVERE WEATHER WATCH IS BEING CONSIDERED FOR ISSUANCE
THIS MORNING INTO THE AFTERNOON ACROSS ERN KS AND WRN/CENTRAL MO.

DISCUSSION...TRENDS IN VISIBLE SATELLITE IMAGERY AND REGIONAL RADARS
ACROSS SERN KS SHOWED AN INCREASE IN AN AGITATED CU FIELD...WHICH IS
LIKELY AN INDICATION OF INCREASING DEEP LAYER ASCENT SPREADING NEWD
ACROSS THIS REGION.  ENHANCED CLOUDS ACROSS SRN KS INTO PARTS OF
CENTRAL OK MAY BE INDICATIVE OF INCREASING ASCENT ATTENDANT TO A 65
KT MIDLEVEL JET/IMPULSE CURRENTLY ANALYZED OVER SWRN KS TO ALONG THE
TX PANHANDLE/WRN OK BORDER...PER WATER VAPOR IMAGERY...AREA WIND
PROFILERS/WSR-88D VWP DATA AND OBJECTIVE ANALYSES.

THIS REGION OF ASCENT IN SERN KS IS LOCATED INVOF A WARM
FRONT...WHICH AT MID MORNING CONTINUED TO ADVANCE RAPIDLY NWD ACROSS
SERN KS AND NOW APPROACHING CENTRAL MO.  LOW LEVEL WAA ATTENDANT TO
A STRONG SWLY LLJ EXTENDING INTO ERN KS TO NRN MO AND WITH THE
DISCUSSION AREA REMAINING IN A STRONGLY DIFFLUENT REGIME SUGGEST
CONVECTION WILL CONTINUE TO DEVELOP...WITH ADDITIONAL TSTM
DEVELOPMENT EXPECTED THIS MORNING INTO THE AFTERNOON.

RECENT RUNS OF THE HRRR AND THE 00Z 4 KM WRF-NSSL SUPPORT THIS
SCENARIO WITH TSTMS GRADUALLY INCREASING IN VICINITY OF AND S OF THE
NWD MOVING WARM FRONT.  AN ENVIRONMENT ALREADY MODERATELY UNSTABLE
WITH STEEP MIDLEVEL LAPSE RATES WILL FAVOR HAIL SIZE OF AT LEAST
1.75 INCH IN DIAMETER.  THE SWLY LLJ IS EXPECTED TO BACK TO SLY IN
RESPONSE TO HEIGHT FALLS SPREADING ACROSS THE CENTRAL/SRN PLAINS
TODAY AHEAD OF THE APPROACHING WRN U.S. LONGWAVE TROUGH.  THIS WILL
INCREASE LOW LEVEL HODOGRAPH CURVATURE...ESPECIALLY BY AFTERNOON FOR
AN ENHANCED TORNADO THREAT.

..PETERS/KERR.. 04/17/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LSX...SGF...EAX...TSA...TOP...ICT...

LAT...LON   37309681 38389610 39769505 39829322 39929224 39289197
            38009233 36989352 36639460 36599573 36889658 37309681

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md0491.html