[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 262309
SWOMCD
SPC MCD 262308 
NDZ000-SDZ000-MTZ000-WYZ000-270115-

MESOSCALE DISCUSSION 1779
NWS STORM PREDICTION CENTER NORMAN OK
0608 PM CDT MON JUL 26 2004

AREAS AFFECTED...PORTIONS EXTREME ERN MT...WRN ND...EXTREME NERN
WY...WRN SD N OF BLACK HILLS

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 262308Z - 270115Z

SCATTERED TO WIDELY SCATTERED TSTMS WILL CONTINUE TO DEVELOP FROM
WESTON/CROOK COUNTIES WY NNEWD TOWARD NWRN CORNER SD...THEN NNWWD
ACROSS ND/MT BORDER REGION THROUGH APPROXIMATELY 00Z.  THIS ACTIVITY
IS FCST TO MOVE EWD ACROSS WRN 1/3 TO 1/4 OF ND...AND THAT PORTION
OF NWRN SD N OF BLACK HILLS.  ISOLATED DAMAGING GUSTS ARE
POSSIBLE...ALONG WITH MOSTLY SMALL HAIL.  WW NOT EXPECTED.

SFC ANALYSIS SHOWS TROUGH/CONFLUENCE LINE ALONG AFOREMENTIONED
CONVECTIVE AXIS.  FLOW IS BACKING E OF THIS FEATURE AND VEERING AT
SOME STATIONS BEHIND IT...BECAUSE OF SOME COMBINATION OF
1. WEAK LEE-SIDE ISALLOBARIC FORCING ASSOCIATED WITH APCHG UPPER
TROUGH OVER ID AND
2. SFC PRESSURE FALLS ASSOCIATED WITH STRONG DIABATIC HEATING.

VERY DEEPLY MIXED AND RELATIVELY DRY BOUNDARY LAYERS CHARACTERIZE
ENVIRONMENT WITH CLOUD BASES ESTIMATED TO BE IN 500-550 MB
LAYER...SFC DEW POINTS IN 40S F...AND MLCAPE 400-700 J/KG.
MODIFIED RUC SOUNDINGS AND AVAILABLE/INTERPOLATED VWP DATA INDICATE
PRONOUNCED WEAKNESS OF BOTH LOW-MIDLEVEL SHEAR AND ABSOLUTE FLOW --
WITH WINDS GENERALLY AOB 10 KT IN 400-900 MB LAYER.  THIS WILL LIMIT
STORM ORGANIZATION AND CONTRIBUTE TO POTENTIAL FOR SUSTAINED 
OUTFLOW-DOMINANCE.  HOWEVER...SHORT-LIVED THREAT EXISTS FOR
LOCALIZED STRONG ASCENT ALONG COLD POOLS BEFORE SLOPE OF OUTFLOW
BECOMES TOO SHALLOW.  EXPECT POTENTIAL FOR DAMAGING WIND TO DIMINISH
MARKEDLY AFTER ABOUT 02Z WITH BOTH EXPANSION OF OUTFLOW COVERAGE AND
LOSS OF BUOYANCY ATTRIBUTABLE TO SFC DIABATIC COOLING.

..EDWARDS.. 07/26/2004

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

ATTN...WFO...BIS...UNR...BYZ...GGW...

49000226 44160227 44200514 48980514 

WWWW