SPC MD 1562

MD 1562 CONCERNING SEVERE THUNDERSTORM WATCH 450… FOR PORTIONS OF CENTRAL AND NORTHERN OKLAHOMA AND SRN KANSAS


MESOSCALE DISCUSSION 1562
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CDT MON JUL 29 2013

AREAS AFFECTED...PORTIONS OF CENTRAL AND NORTHERN OKLAHOMA AND SRN
KANSAS

CONCERNING...SEVERE THUNDERSTORM WATCH 450...

VALID 300059Z - 300230Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 450
CONTINUES.

SUMMARY...THE SVR THREAT CONTINUES ACROSS SVR TSTM WATCH 450. SOME
DMGG-WIND POTENTIAL COULD EXTEND S OF THE ONGOING WATCH LATER THIS
EVENING. THIS COULD EVENTUALLY BE ADDRESSED BY A LOCAL SWD EXPANSION
OF THE WATCH.

DISCUSSION...THE PRIMARY SVR THREAT IS GRADUALLY BECOMING FOCUSED
WITHIN SRN PARTS OF THE WW AREA IN ASSOCIATION WITH AN ORGANIZING
MCS AND ACCOMPANYING COLD POOL ACCELERATIONS. THE LEADING CONVECTIVE
LINE EXTENDS FROM HARPER COUNTY KS TO GRANT AND ALFALFA COUNTIES OK
AND IS BACKBUILDING FARTHER W INTO HARPER COUNTY OK. A STRONGER COLD
POOL SURGE GLANCED THE MAY RANCH MESONET STATION EARLIER...PRODUCING
A 56-MPH WIND GUST. A SLY LLJ SEEMS TO BE SUPPORTING AN UPTICK IN
CONVECTION...BOTH S OF THE AFOREMENTIONED CONVECTION IN PARTS OF
W-CNTRL OK AND ALONG THE BACKBUILDING SEGMENT.

MID-LEVEL LAPSE RATES AND MID-LEVEL FORCING FOR ASCENT ARE ONLY
MODEST ACROSS THE REGION. HOWEVER...RICH TROPOSPHERIC MOISTURE --
E.G. LOWEST-100-MB MEAN MIXING RATIO OF 18.2 G/KG AND PW VALUE OF
2.13 INCHES PER THE 00Z NORMAN SOUNDING -- AND MODERATE/STRONG
BOUNDARY-LAYER BUOYANCY EXIST S OF ONGOING CONVECTION. AND...WITH
CONVERGENCE AT THE LEADING EDGE OF STRENGTHENING/AMALGAMATING COLD
POOLS AUGMENTED BY MASS CONVERGENCE AT THE TERMINUS OF A 30-40-KT
LLJ...MAINTENANCE AND/OR SWD/SEWD PROPAGATION OF THE MCS AND
ACCOMPANYING DMGG-WIND POTENTIAL MAY EXTEND S OF THE ONGOING WW.
LOWERING LCL HEIGHTS AND AT LEAST MODEST LOW-LEVEL HELICITY -- E.G.
EFFECTIVE SRH AROUND 215 M2/S2 PER THE 00Z OUN RAOB -- COULD SUPPORT
QLCS-EMBEDDED MESOVORTICES WITH ENHANCED CORRIDORS OF DMGG WIND
GUSTS AND POSSIBLY SOME BRIEF TORNADO POTENTIAL. THIS COULD
EVENTUALLY BE HANDLED WITH A LOCAL SWD EXPANSION OF THE ONGOING
WATCH.

FARTHER TO THE N ACROSS PARTS OF SRN KS...CONVECTION CONTINUES N OF
AN EFFECTIVE FRONT THAT IS BEING MODULATED BY STRONGER CONVECTION TO
ITS N. DESPITE INFLOW OF COMPARATIVELY LESS BUOYANCY RELATIVE TO
CONVECTION FARTHER S...HIGH PW AMIDST MODERATE DEEP SHEAR WILL
SUPPORT WATER LOADING AND THE POTENTIAL FOR SPORADIC DMGG WIND
GUSTS.

..COHEN/CORFIDI.. 07/30/2013

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

ATTN...WFO...TSA...TOP...ICT...OUN...DDC...

LAT...LON   38159981 38419719 37889524 36609518 35969552 35669665
            35619861 36109992 38159981

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1562.html