Saturday, April 21, 2007

MESO: Mesoscale Discussion 0524

ACUS11 KWNS 211835
SWOMCD
SPC MCD 211835
SDZ000-NEZ000-COZ000-211930-

MESOSCALE DISCUSSION 0524
NWS STORM PREDICTION CENTER NORMAN OK
0135 PM CDT SAT APR 21 2007

AREAS AFFECTED...NERN CO....WCNTRL AND NCNTRL NEB...SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 211835Z - 211930Z

SEVERE TSTM DEVELOPMENT IS EXPECTED ACROSS AREAS OF THE CENTRAL
PLAINS THIS AFTERNOON. A WATCH IS MOST LIKELY FROM PARTS OF CNTRL
NEB ACROSS SECTIONS OF SCNTRL AND ERN SD IN THE NEXT HOUR OR SO.

QUASI-STATIONARY /SW-TO-NE ORIENTED/ FRONTAL ZONE LIES APPROXIMATELY
ALONG A LINE FROM LIC-40NW LBF-10E VTN-20W 9V9 AT 18Z. WEAK 1005MB
SURFACE FRONTAL WAVE WAS LOCATED NEAR SFD IN SCNTRL SD. CAPPED WARM
SECTOR AIR MASS ALONG AND SOUTH OF THE FRONT CONTINUES TO GRADUALLY
DESTABILIZE THIS AFTERNOON AS WARMING AND INCREASING LOW LEVEL
MOISTURE CONTRIBUTE TO MLCAPE APPROACHING 1000 J/KG. CAPPING
INVERSION EVIDENT ON LATEST OBSERVED LBF AND OTHER MODEL SOUNDINGS
SHOULD CONTINUE TO SLOWLY ERODE AS BOTH HEATING AND LARGE SCALE
FORCING FOR LIFT INCREASE ACROSS THE AREA THROUGH THE AFTERNOON.
STRONGER MESOSCALE ASCENT NEAR THE FRONTAL CIRCULATION...AND WEAKER
INHIBITION ALONG AND ON THE COOL-SIDE OF THE BOUNDARY /SEE 17Z ABR
SOUNDING/...MAY HASTEN CONVECTIVE DEVELOPMENT NEARER THE FRONT IN
THE NEXT 1-2 HOURS. ALTHOUGH THIS INITIAL DEVELOPMENT MAY REMAIN
DECOUPLED FROM DEEPENING WARM SECTOR BOUNDARY LAYER...ACTIVITY WILL
OCCUR WITHIN AN ENVIRONMENT CHARACTERIZED BY MORE THAN SUFFICIENT
SHEAR AND STEEP LAPSE RATES FOR LARGE HAIL PRODUCTION.

COLD POOL FROM STORMS INCREASING ALONG AND WEST OF THE BOUNDARY MAY
FURTHER ENHANCE LIFT AND PROMOTE SURFACE-BASED STORMS BY LATE
AFTERNOON AS CAP ERODES AND STRONGER LARGE SCALE FORCING WITH THE
UPPER TROUGH SPREADS NEWD. LATEST FORECAST SOUNDINGS INDICATE AN
INCREASING RISK OF SUPERCELLS WITH LARGE HAIL...DAMAGING WINDS...AND
TORNADOES AS THIS PROCESS UNFOLDS.

.CARBIN.. 04/21/2007

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

ATTN...WFO...FSD...ABR...LBF...UNR...BOU...

45569924 45749729 44939754 43379943 41270057 40760208
40840236 41710254 44950029

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