[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 212035
SWOMCD
SPC MCD 212034 
AZZ000-212230-

MESOSCALE DISCUSSION 2347
NWS STORM PREDICTION CENTER NORMAN OK
0334 PM CDT THU OCT 21 2004

AREAS AFFECTED...PORTIONS S-CENTRAL/SERN AZ

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 212034Z - 212230Z

NARROW CORRIDOR OF SEVERE WIND/HAIL POTENTIAL MAY DEVELOP AND MOVE
EWD ACROSS PORTIONS CENTRAL/SRN AZ THROUGH AFTERNOON.  WW NOT
ANTICIPATED ATTM BUT WILL CONTINUE TO MONITOR.

EXTENSIVE SSW-NNE ORIENTED CLOUD/PRECIP BELT COVERS MUCH OF WRN AZ
AND SERN CA.  THIS FEATURE IS DRIFTING EWD ATTM AND WILL ACCELERATE 
TO 10-15 KT EWD TRANSLATIONAL SPEED ACROSS REGION THROUGH LATE
AFTERNOON...SIGNIFICANTLY LIMITING FURTHER DESTABILIZATION IN AREAS
NOW JUST OFF ITS ERN EDGE.  ISOLATED TSTMS HAVE STARTED TO DEVELOP
WITHIN THIS BELT...POSING MINIMAL SEVERE POTENTIAL BECAUSE OF LACK
OF SFC-BASED INSTABILITY.  SFC COLD FRONT IS COLLOCATED WITH ERN
EDGE OF THIS BAND.

HOWEVER...ROUGHLY 75 NM WIDE AREA AHEAD OF FRONTAL BAND HAS
EXPERIENCED HOURS OF RELATIVELY CLEAR SKIES AND THEREFORE
HEATED/DESTABILIZED SUBSTANTIALLY.  MEANWHILE LAPSE RATES ALOFT ARE
INCREASING IN CONJUNCTION WITH LARGE SCALE ASCENT SPREADING SLOWLY
OVER AREA.  MODIFIED MORNING RAOBS AND MODEL SOUNDINGS INDICATE
REMOVAL OF MIDLEVEL WARM LAYER...AND PRESENT TEMPS/DEW POINTS
OBSERVED JUST E OF CLOUD SHIELD...WOULD RESULT IN NEARLY UNCAPPED
THERMODYNAMIC PROFILE WITH ABOUT 300-500 J/KG MLCAPE.  THIS IS
SUPPORTED BY INCREASING COVERAGE/DEPTH OF CUMULIFORM CLOUDS IN
HEATED CORRIDOR...AND LIKELIHOOD OF OROGRAPHIC ASCENT ON S AND SW
FACING SLOPES. VERTICAL SHEAR IS STRONG -- PERHAPS TOO STRONG FOR
MANY UPDRAFTS TO SURVIVE GIVEN ROUGHLY 100 KT 0-6 KM SHEARS IN TUS
VWP.  ANY SUSTAINED CELLS OR SHORT LINE SEGMENTS MAY PRODUCE
STRONG-SEVERE GUSTS IN ADDITION TO THOSE ACCOMPANYING FRONTAL
PASSAGE ITSELF.

..EDWARDS.. 10/21/2004

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

ATTN...WFO...TWC...FGZ...PSR...

31801255 32571212 33641157 34371134 34501082 34251014
33660995 32391031 31311099 

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