MESO: Mesoscale Discussion 1553

ACUS11 KWNS 282253
SWOMCD
SPC MCD 282252
UTZ000-WYZ000-AZZ000-NVZ000-CAZ000-290115-

MESOSCALE DISCUSSION 1553
NWS STORM PREDICTION CENTER NORMAN OK
0552 PM CDT SUN JUL 28 2013

AREAS AFFECTED...PORTIONS OF ERN CA...CNTRL/SRN NV...UT...NWRN AZ

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 282252Z - 290115Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A BROAD AREA OF MARGINAL/ISOLATED SVR POTENTIAL WILL EXIST
INTO THE EVENING HOURS...THOUGH THE ISSUANCE OF A WW IS NOT
ANTICIPATED.

DISCUSSION...LOW/MID-LEVEL MONSOONAL MOISTURE IS BEING COMPLEMENTED
BY THE INFLUX OF A SUBTROPICAL MOISTURE STREAM LEADING A MID-LEVEL
CYCLONE MOVING TOWARD THE SRN CA COAST. WHILE THE MCD AREA IS WELL
DOWNSTREAM OF ANY SUBSTANTIAL DEEP FORCING FOR ASCENT PRECEDING THE
CYCLONE...THE PRESENCE OF ENHANCED TROPOSPHERIC MOISTURE CONTENT --
E.G. PW VALUES AROUND 1.0-1.6 INCHES PER GPS DATA -- AMIDST
OROGRAPHIC CIRCULATIONS CONTINUES AIDING A BROAD AREA OF ISOLATED TO
SCATTERED THUNDERSTORMS. MARGINAL TO LOCALLY MODERATE BOUNDARY-LAYER
BUOYANCY IS BEING SUPPORTED BY STEEP LOW-LEVEL LAPSE RATES IN AREAS
OUTSIDE OF ONGOING THUNDERSTORM ACTIVITY/ANVIL SHADING. MODESTLY
WELL-SCULPTED DOWNSHEAR ANVIL STRUCTURES PER VISIBLE SATELLITE
IMAGERY SUGGEST THAT STORMS ARE RESPONDING TO VENTILATION PROCESSES
ACCOMPANYING A HIGH-LEVEL JET EXTENDING DOWNSTREAM OF THE
AFOREMENTIONED CYCLONE. THIS SHOULD ALSO AID IN CONVECTIVE
MAINTENANCE INTO THE EVENING HOURS. HOWEVER...REGIONAL VWP DATA
SUGGEST THAT MID-LEVEL FLOW IS GENERALLY LIMITED ACROSS THE
REGION...WHICH SHOULD DECREASE THE POTENTIAL FOR THE SUSTENANCE OF
MORE ORGANIZED CONVECTIVE STRUCTURES. NEVERTHELESS...ABUNDANT
SUB-CLOUD EVAPORATION AND DCAPE...ALONG WITH PRECIPITATION
LOADING...WILL AID IN THE POTENTIAL FOR SPORADIC MARGINALLY SVR WIND
GUSTS ACROSS THE AREA. MARGINALLY SVR HAIL CANNOT BE RULED OUT...AS
WELL.

..COHEN/CORFIDI.. 07/28/2013

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

ATTN...WFO...SLC...VEF...LKN...REV...

LAT...LON 37431786 39691639 41291387 41561196 40961094 39751065
37521301 34891385 35781731 37431786

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