[MCD] SWOMCD

Wed Sep 20 20:04:49 UTC 2006

ACUS11 KWNS 202005
SWOMCD
SPC MCD 202005 
COZ000-NMZ000-WYZ000-AZZ000-UTZ000-202230-

MESOSCALE DISCUSSION 1989
NWS STORM PREDICTION CENTER NORMAN OK
0305 PM CDT WED SEP 20 2006

AREAS AFFECTED...PORTIONS NWRN NM...EXTREME NERN AZ...WRN CO...SWRN
WY...CENTRAL/ERN UT.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 202005Z - 202230Z

CONVECTION WILL CONTINUE TO INCREASE IN COVERAGE THROUGH AT LEAST
23Z ACROSS BROAD SWATH FROM 4-CORNERS AREA NWD TOWARD SWRN WY.

SEVERAL BANDS OF ASCENT ARE EVIDENT AHEAD OF PRONOUNCED MID-UPPER
LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER WRN UT. 
ONE OF THEM IS MANIFEST AS BROAD AREA OF PRECIP WITH
EMBEDDED/STRENGTHENING TSTMS...FROM ERN MOFFAT COUNTY COL SSWWD
ACROSS GJT AREA TO 4-CORNERS...BECOMING NARROWER FARTHER SW INTO
N-CENTRAL NAVAJO COUNTY AZ.  THIS ACTIVITY IS EXPECTED TO MOVE ENEWD
OVER NWRN NM...REMAINDER WRN CO...AND PERHAPS ADJACENT PORTIONS SWRN
WY.  NEXT BAND TO ITS W CONTAINS STRENGTHENING TSTMS FROM VEL SWWD
TO WAYNE COUNTY UT...THEN DISCONTINUOUS SWWD TO NEAR PGA. 
DEEP-LAYER SHEAR AND BOUNDARY LAYER BUOYANCY ARE FCST TO INCREASE
CONCURRENTLY AHEAD OF EACH BAND...AS INSOLATION CONTINUES IN
RELATIVELY CLOUD-FREE AREAS...AND AS MIDLEVEL HEIGHT GRADIENT
TIGHTENS AHEAD OF DIGGING UPPER VORTEX.  INITIAL BAND WILL MOVE
THROUGH NARROW AREA OF HEATED/ELEVATED TERRAIN WITH UP TO 200 J/KG
MLCAPE...BETWEEN CURRENT POSITION AND SWATH OF DRIER SFC AIR
BEGINNING AROUND AN EGE...ASE...GUC...50 E FMN LINE. THEREAFTER
ACTIVITY MAY WEAKEN BECAUSE AIR MASS BECOMES TOO DRY TO SUSTAIN DEEP
BUOYANCY.  DAMAGING WIND IS MAIN THREAT.

SECOND BAND -- CORRESPONDING CLOSELY TO SFC COLD FRONT POSITION --
WILL MOVE INTO AN AREA BEHIND FIRST WHICH IS NOT AS STRONGLY
HEATED...BUT WHICH HAS STEEPER MIDLEVEL LAPSE RATES.  NET RESULT
ALSO WILL BE MLCAPES INCREASING TO 200-400 J/KG.  THIS AREA
REPRESENTS OVERLAP BETWEEN ERN EDGE OF COLDEST AIR ALOFT AND WRN
PORTION STRONGEST DEEP-LAYER SHEAR...WITH EFFECTIVE SHEARS BECOMING
40-50 KT.  MOST INTENSE CELLS MAY PRODUCE HAIL AND/OR DAMAGING
GUSTS. FARTHER W...MORE ISOLATED/POSTFRONTAL ACTIVITY UNDER COLD
CORE REGION WILL PRESENT MAINLY HAIL THREAT AMIDST VERY STEEP
MIDLEVEL LAPSE RATES BUT WEAK SHEAR.

..EDWARDS.. 09/20/2006

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

ATTN...WFO...PUB...BOU...CYS...ABQ...RIW...GJT...FGZ...SLC...

35891051 36900971 37610981 37631042 37301152 37981236
39581224 40501037 41640850 41680702 40530637 38480666
36910732 36050867 