SPC MD 1540

MD 1540 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS N-CENTRAL THROUGH SERN CO…WY NEAR I-25…WRN KS.


MESOSCALE DISCUSSION 1540
NWS STORM PREDICTION CENTER NORMAN OK
0305 PM CDT SAT JUL 27 2013

AREAS AFFECTED...PORTIONS N-CENTRAL THROUGH SERN CO...WY NEAR
I-25...WRN KS.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 272005Z - 272200Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED TSTMS OVER WY AND WIDELY SCATTERED TO SCATTERED
TSTMS OVER CO SHOULD MOVE SEWD OFF ERN-MOST MTNS AND
FOOTHILLS...WITH POTENTIAL FOR LARGE HAIL AND DAMAGING GUSTS.
SIMILAR SVR-MODE THREAT ALSO EXISTS ESEWD INTO WRN KS BUT MORE
CONDITIONAL.

DISCUSSION...AT 1930Z...SFC MESOANALYSIS SHOWED PRIMARY LOW BETWEEN
PUB-COS...WITH QUASISTATIONARY FRONT EWD TO SECONDARY LOW BETWEEN
LAA-ITR...AND WARM FRONT SEWD TO BETWEEN DDC-GCK.  CO SEGMENT OF
FRONT SHOULD MOVE LITTLE FOR ANOTHER 2-3 HOURS.  AIR MASS S OF THIS
BOUNDARY WAS CHARACTERIZED BY VERY DEEPLY MIXED AND RELATIVELY DRY
BOUNDARY LAYER WITH SFC DEW POINTS 40S F...JUST MOIST ENOUGH TO
SUPPORT MRGL BUOYANCY WITH MLCAPE AOB 500 J/KG.
FARTHER N...STRONGER BAROCLINIC ZONE ACTUALLY IS ASSOCIATED WITH
COMBINED DIFFERENTIAL-HEATING/OUTFLOW BOUNDARY THAT WAS DRAWN NEAR
GBD-LIC-DEN-FNL THEN BECOMING ILL-DEFINED NWWD TOWARD LAR.  SFC
THETAE AXIS WAS EVIDENT JUST SW OF AND PARALLEL TO THIS
BOUNDARY...ALONG WITH JUXTAPOSITION OF AROUND 1500 J/KG MLCAPE AND
45-50 KT EFFECTIVE SHEAR MAGNITUDE...SUPPORTING MOST
SUSTAINED/CONCENTRATED SVR THREAT.  ACTIVITY MOVING S OF FRONT WILL
ENTER WELL-MIXED LAYER WITH SOME ENHANCEMENT TO GUST POTENTIAL.
ACTIVITY MAY DEVELOP NEAR BOUNDARY IN SERN CO OR WRN KS AS
WELL...WHERE FAVORABLE COMBINATION OF BUOYANCY AND SHEAR IS ALSO IS
EVIDENT...BUT POTENTIAL IS MORE CONDITIONAL GIVEN STRONGER CINH OVER
THOSE AREAS.

TEMPS 50S-60S F CHARACTERIZE AIR MASS OVER NERN CO AND WRN NEB N OF
THIS BOUNDARY...WITH LITTLE ADDITIONAL WARMING EXPECTED THERE DUE TO
PERSISTENT STRATUS COVER.  HOWEVER...NARROW CORRIDOR E OF BOUNDARY
IN WY AND EXTREME NRN CO HAS CLEARED/HEATED ENOUGH TO SUPPORT
500-1000 J/KG MLCAPE VERY NEAR I-25.  ACTIVITY DEVELOPING OVER
BIGHORN AND LARAMIE RANGES IS IN KINEMATIC ENVIRONMENT SUPPORTING
SUPERCELL DEVELOPMENT...WITH EFFECTIVE SHEAR MAGNITUDE AROUND 50 KT.
THIS THREAT IS CONDITIONAL ON TSTMS MATURING AND RIGHT-MOVING BEFORE
ENTERING STABLE AIR MASS JUST E OF I-25.

..EDWARDS/THOMPSON.. 07/27/2013

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

ATTN...WFO...DDC...UNR...GLD...PUB...BOU...CYS...RIW...

LAT...LON   37570296 37990435 39280530 42000602 44220685 44190621
            43080556 41560503 40110447 39380314 38540068 37260108
            37570296

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1540.html