SWOMCD
SPC MCD 142010 COR
MOZ000-KSZ000-NEZ000-142200-
MESOSCALE DISCUSSION 1559
NWS STORM PREDICTION CENTER NORMAN OK
0310 PM CDT TUE JUL 14 2009
AREAS AFFECTED...CENTRAL-ERN KS...NWRN MO...SERN NEB
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 142010Z - 142200Z
CORRECTED FOR DESCRIPTION OF SURFACE FEATURES
LARGE HAIL/DAMAGING WINDS ALONG WITH AN ISOLATED TORNADO OR TWO ARE
POSSIBLE WITH SURFACE BASED THUNDERSTORM DEVELOPMENT OCCURRING OVER
CENTRAL-NERN KS...NWRN MO...AND SERN NEB. A WW WILL LIKELY BE NEEDED
AS STORM INITIATION BECOMES MORE APPARENT.
SUBJECTIVE SURFACE ANALYSIS PLACES A 1007 MB LOW NEAR RSL...WITH A
WARM FRONT SURGING NEWD INTO NERN KS...AND A COLD FRONT SLIDING SSE
THROUGH WRN KS AND CENTRAL NEB. SURFACE TEMPERATURES ARE IN THE 90S
TO LOW 100S SW OF THE WARM FRONT...WHILE DEWPOINTS RESIDE IN THE LOW
70S ALONG AND TO THE COOL SIDE OF THE WARM FRONT. THIS HIGH THETA-E
AIRMASS IS OVERLAID BY A PLUME OF STEEP MID LEVEL LAPSE
RATES...RESULTING IN A VERY TO EXTREMELY UNSTABLE ATMOSPHERE. THE
WARM EML IS ALSO PROVIDING A CAP TO THUNDERSTORM DEVELOPMENT THUS
FAR. HOWEVER...UPPER LEVEL DIVERGENCE ASSOCIATED WITH THERMALLY
DIRECT CIRCULATION WITHIN RRQ OF CENTRAL/NRN PLAINS JET STREAK WILL
RESULT IN INCREASING FORCING FOR ASCENT WITH APPROACHING COLD FRONT
DURING THE LATE AFTERNOON INTO THE NIGHT TIME HRS. IN
ADDITION...SSWLY LOW LEVEL JET IS FORECAST TO STRENGTHEN BY
00Z...FOCUSING LOW LEVEL CONVERGENCE AND WAA OVER NERN KS AND NWRN
MO. THESE FORCING FEATURES MAY BE SUFFICIENT FOR THUNDERSTORM
INITIATION DURING THE 21-00Z TIME FRAME.
SELY SURFACE WINDS ALONG AND TO THE COOL SIDE OF THE WARM FRONT VEER
TO 25 KT OF SWLY FLOW IN THE 1-3 KM LAYER PER AREA PROFILER AND VWP
DATA...AND THEN 30-40 KT WLY FLOW AT 6 KM. THIS WIND PROFILE YIELDS
FAVORABLE HODOGRAPH STRUCTURE AND DEEP LAYER VERTICAL WIND SHEAR
/EFFECTIVE BULK SHEAR VALUES AOA 40 KT/ FOR SUPERCELLS. THOUGH
MELTING POTENTIAL WILL BE HIGH GIVEN HOT/MOIST BOUNDARY LAYER...THE
COMBINATION OF STEEP MID LEVEL LAPSE RATES...LARGE CAPE...AND STRONG
VERTICAL WIND SHEAR SUGGESTS VERY LARGE HAIL IS POSSIBLE WITH ANY
PERSISTENT SUPERCELL STRUCTURES...AS WELL AS DAMAGING WIND GUSTS. IN
ADDITION...LOW LEVEL VERTICAL WIND SHEAR MAXIMIZED ALONG THE WARM
FRONT MAY BE FAVORABLY COLLOCATED WITH SURFACE BASED INSTABILITY AND
LOW LCL HEIGHTS...RESULTING IN AN ISOLATED TORNADO THREAT BEFORE
FRONTAL FORCING EVENTUALLY FAVORS A MORE QUASI-LINEAR MODE OF
CONVECTION.
..GARNER.. 07/14/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...SGF...EAX...OAX...TOP...ICT...GID...
LAT...LON 39649799 40429646 40509487 40039381 38999375 37989488
37789687 38099788 38719837 39649799
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