[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 212201
SWOMCD
SPC MCD 212200 
SDZ000-NDZ000-NEZ000-212330-

MESOSCALE DISCUSSION 1815
NWS STORM PREDICTION CENTER NORMAN OK
0500 PM CDT THU JUL 21 2005

AREAS AFFECTED...SWRN ND AND WRN SD

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 212200Z - 212330Z

THREAT OF PRIMARILY LARGE HAIL AND DAMAGING WINDS IS EXPECTED TO
INCREASE ACROSS DISCUSSION AREA THIS EVENING. A WW WILL LIKELY BE
REQUIRED.

RAPID TSTM DEVELOPMENT HAS OCCURRED OVER THE PAST HALF HOUR OR SO
OVER PORTIONS OF SWRN ND...NAMELY SLOPE AND ADAMS COUNTIES.
MESOANALYSIS AND RUC OBJECTIVE FIELDS SUGGEST THIS ACTIVITY IS
OCCURRING IN A REGION OF ENHANCED LOW-LEVEL CONVERGENCE NE OF A WEAK
SURFACE LOW SITUATED NEAR REJ. HERE...TEMPERATURES IN THE UPPER 80S
TO LOWER 90S COUPLED WITH DEWPOINTS IN THE MID 60S HAVE ALLOWED AIR
MASS TO BECOME MODERATELY UNSTABLE WITH LITTLE OR NO CONVECTIVE
INHIBITION. WHILE WATER VAPOR IMAGERY INDICATES THAT REGION IS
BENEATH GRADUAL HEIGHT RISES...IT APPEARS THAT THE
MESOSCALE...LOW-LEVEL FORCING IS SUFFICIENTLY STRONG TO OVERCOME
LARGER-SCALE SUBSIDENCE.

CURRENT VWP FROM BIS INDICATES THAT VERTICAL SHEAR IS QUITE
FAVORABLE FOR SUPERCELLS GIVEN SLY SURFACE FLOW VEERING TO WLY AT
40-45 KTS IN THE MID-LEVELS. GIVEN DEEP AND WELL-MIXED
BOUNDARY-LAYER...STORMS SHOULD QUICKLY BECOME MORE OUTFLOW-DOMINANT
WITH THE PRIMARY SEVERE WEATHER THREATS BEING LARGE HAIL AND
DAMAGING WINDS.

FARTHER S...ADDITIONAL TSTMS ARE BEGINNING TO DEVELOP OVER THE BLACK
HILLS...AIDED BY CONVERGENCE ALONG LEE TROUGH. HERE TOO...AIR MASS
HAS BECOME MODERATELY UNSTABLE...THOUGH OBJECTIVE FIELDS INDICATE A
SLIGHTLY STRONGER CAP. SHOULD STORMS BECOME SUSTAINED...SUFFICIENT
VERTICAL SHEAR EXISTS FOR SUPERCELLS CAPABLE OF LARGE HAIL AND
DAMAGING WINDS.

..MEAD.. 07/21/2005

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

ATTN...WFO...ABR...BIS...LBF...UNR...CYS...

46160357 46800334 47110271 47020169 46080097 43080199
42800251 42860366 43180401 

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