SPC MD 839

MD 0839 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR NWRN OK THROUGH CNTRL KS INTO SERN NEB AND SWRN IA


MESOSCALE DISCUSSION 0839
NWS STORM PREDICTION CENTER NORMAN OK
0236 PM CDT SAT MAY 19 2012

AREAS AFFECTED...NWRN OK THROUGH CNTRL KS INTO SERN NEB AND SWRN IA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 191936Z - 192100Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...INITIAL STORMS ARE EXPECTED TO DEVELOP 21-22Z FROM PARTS
OF CNTRL KS INTO ERN NEB. ADDITIONAL STORMS MAY DEVELOP A LITTLE
LATER FARTHER SOUTH FROM SCNTRL KS INTO NWRN OK. POTENTIAL WILL
EXIST FOR BOTH SUPERCELLS AND BOWING LINE SEGMENTS WITH LARGE HAIL
AND DAMAGING WIND THE MAIN THREATS.

DISCUSSION...A COLD FRONT EXTENDS ACROSS ERN NEB SWWD THROUGH WCNTRL
KS INTO THE OK AND TX PANHANDLES. A DRYLINE STRETCHES FROM WRN TX
NWD INTO SWRN KS WHERE IT INTERSECTS THE COLD FRONT. THE WARM SECTOR
HAS BECOME MODERATELY UNSTABLE WITH 1500-2000 J/KG MLCAPE BASED ON
LATEST OBJECTIVE ANALYSIS...BUT IS STRONGLY CAPPED BY A WARM EML
THAT HAS ADVECTED INTO THIS REGION. SATELLITE IMAGERY INDICATES A
BAND OF MID-HIGH LEVEL CLOUDS ADVANCING THROUGH WRN KS AND MAY BE
INDICATIVE OF THE LEADING EDGE OF MID LEVEL ASCENT ASSOCIATED WITH
AN UPPER JET STREAK ROUNDING BASE OF SHORTWAVE TROUGH. THE CAP WILL
WEAKEN AS THE ARRIVAL OF DEEPER ASCENT OVERTAKES THE WRN EDGE OF
WARM SECTOR. STORMS ARE EXPECTED TO DEVELOP WITHIN THE ZONE OF
MESOSCALE FORCING ALONG THE FRONT BY 21-22Z MOST LIKELY FROM CNTRL
KS THROUGH ERN NEB. BOUNDARY LAYER MOISTURE IS MODEST WITH UPPER 50S
DEWPOINTS AND TEMPERATURES CLIMBING INTO THE UPPER 80S PROMOTING
LARGE BOUNDARY LAYER TEMPERATURE-DEWPOINT SPREADS. DEEP SHEAR HAS
INCREASED TO 40-50 KT IN FRONTAL ZONE SUPPORTIVE OF SUPERCELLS...BUT
THE RELATIVELY DRY SUB CLOUD LAYER SUGGESTS STORMS WILL LIKELY
BECOME OUTFLOW DOMINANT WITH DAMAGING WIND AND LARGE HAIL THE MAIN
THREATS. ADDITIONAL MORE ISOLATED ACTIVITY MAY DEVELOP ALONG THE
DRYLINE FARTHER SOUTH INTO NWRN OK AFTER 22Z.

..DIAL/WEISS.. 05/19/2012

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

ATTN...WFO...EAX...OAX...TOP...ICT...OUN...GID...DDC...

LAT...LON   41169518 37579718 36049853 36379943 37629951 38719914
            39579882 40199840 40749785 41139737 41859598 41169518

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md0839.html