Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 271653
SWOMCD
SPC MCD 271653
UTZ000-AZZ000-271800-

MESOSCALE DISCUSSION 1770
NWS STORM PREDICTION CENTER NORMAN OK
1153 AM CDT SAT SEP 27 2014

AREAS AFFECTED...AZ...UT

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 271653Z - 271800Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...CHANCES FOR ORGANIZED THUNDERSTORMS POSING SOME RISK FOR
HIGH WINDS AND HAIL SHOULD INCREASE INTO THE AFTERNOON HOURS ACROSS
PARTS OF CENTRAL/NORTH-CENTRAL AZ AND SOUTH-CENTRAL UT.

DISCUSSION...A BROKEN BAND OF VIGOROUS CONVECTION CONTINUES ACROSS
WESTERN AZ INTO SOUTHWEST UT AHEAD OF A STRONG AND SLOW-MOVING UPPER
TROUGH/LOW CENTERED OVER EASTERN CA/WESTERN NV. DEEP-LAYER ASCENT
AIDED BY HEIGHT FALLS AND ENTRANCE REGION OF MID/UPPER JET ROUNDING
THE EASTERN FLANK OF THE CA LOW WILL SPREAD GRADUALLY EAST ACROSS
THE BULK OF CENTRAL AZ AND SOUTHERN UT THROUGH THE DAY. CONFLUENT
LOW-LEVEL FLOW AND RESULTANT MASS AND MOISTURE FLUXES IN RESPONSE TO
THE UPPER FORCING...IN ADDITION TO OROGRAPHIC
ENHANCEMENT/LIFT...SHOULD CONTINUE TO SUPPORT THUNDERSTORM
DEVELOPMENT AMIDST MODEST LAPSE RATES AND INSTABILITY BOOSTED BY
POCKETS OF STRONGER INSOLATION.

OVER THE LAST SEVERAL HOURS...OCCASIONALLY LONGER-LIVED CELLS WITHIN
THE LARGER CONVECTIVE PLUME HAVE EXHIBITED ROTATION AND LEWP
STRUCTURES INDICATIVE OF A CAPE/SHEAR ENVIRONMENT SUPPORTIVE OF
SEVERE WEATHER IN THE FORM OF HAIL AND LOCALLY STRONG/DAMAGING
WINDS. NOW THAT DIURNAL HEATING CYCLE IS UNDERWAY AND DEEP-LAYER
WIND FIELDS SHOULD CONTINUE TO GRADUALLY STRENGTHEN AS THE TROUGH
EDGES EAST...THE CHANCES FOR LINE SEGMENTS AND A FEW SUPERCELLS
SHOULD INCREASE WITH EASTWARD EXTENT AND A NEW WATCH WILL BE NEEDED
TO ACCOUNT FOR THIS EVOLUTION THROUGH THE AFTERNOON.

..CARBIN/MEAD.. 09/27/2014

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

ATTN...WFO...GJT...FGZ...SLC...PSR...VEF...

LAT...LON   37661314 38521261 38651223 38621118 37531061 35961040
            34261077 32721247 32521397 33311348 34411329 36471318
            37661314




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