MESOSCALE PRECIPITATION DISCUSSION 0687
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
749 AM EDT THU SEP 22 2016
 
AREAS AFFECTED...CENTRAL/EASTERN UT...NORTHERN AZ...SOUTHWEST WY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 221150Z - 221750Z
 
SUMMARY...ISOLATED EMBEDDED CONVECTION WITHIN TROPICAL CONNECTED
MOISTURE STREAM THAT IS SLOW TO ADVANCE EASTWARD MAY POSE SHORT
TERM FLASH FLOOD THREAT PARTICULARLY IN COMPLEX TERRAIN.

DISCUSSION...BLENDED TPW/CIRA LAYERED TPW FIELDS DENOTE TROPICAL
FEED OF MOISTURE ASSOCIATED WITH MID-LEVEL REMNANTS OF PAINE FROM
OF THE SEA OF CORTEZ THROUGH THE WARM CONVEYOR BELT STRETCHING
ACROSS E AZ INTO CENTRAL UT AND SW WY IN ADVANCE OF VERY DEEP (3
STD DEV) LARGE SCALE UPPER LOW SHIFTING INTO THE GREAT BASIN
TODAY.  THE REMNANT ENERGY OF PAINE REMAINS DETECTABLE IN WV
SHEARING WITH TIME ACROSS S NV INTO UT...THIS COUPLED WITH NICELY
CYCLONICALLY CURVED 90-100 KT POLAR JET PROVIDES EXCELLENT
DIFFLUENCE/DIVERGENCE ZONE ACROSS THE MAJORITY OF UTAH AT THIS
TIME.  STRENGTHENING LOWER LEVEL FLOW IS FAIRLY UNIDIRECTIONAL
WITH THE UPPER PATTERN PROVIDING A PERSISTENT CORRIDOR OF LOW
LEVEL MOISTURE TRANSPORT/ASCENT WITH REPEAT TRACKING OF SHOWERS
WITH ISOLATED EMBEDDED CONVECTIVE ELEMENTS (PER ISOLATED LIGHTNING
STRIKES).  SOME UPPER LEVEL CAA AND TDS IN THE UPPER 50S/LOWER 60S
(1.25 TPWS) ALONG WITH MILD INSTABILITY WITH MLCAPES AOA 500 J/KG
EVEN AT DIURNAL MINIMA SUPPORTS SOME VERTICAL DEPTH TO EMBEDDED
CONVECTIVE ELEMENTS.  THESE CORES SHOULD SUPPORT SOME ISOLATED .5"
ONE-HOUR TOTALS WHICH IS NEAR FLASH FLOOD GUIDANCE IN THE
VICINITY.  THIS IN COMBINATION WITHIN THE BROAD PROLONGED TRAINING
OF MODERATE SHOWERY ACTIVITY MAY POSE FLOODING/FLASH FLOODING
CONCERNS THROUGHOUT THE EARLY MORNING AS IT VERY SLOWLY SHIFTS
EASTWARD. ADDITIONAL  UPSTREAM DEVELOPMENT IS EXPECTED WITH
SUBSEQUENT SUBTLE SHORTWAVE LIFTING NORTHEAST OUT OF THE BASE OF
THE TROF (S NV) AROUND 14-15Z.  

GALLINA

ATTN...WFO...FGZ...GJT...RIW...SLC...VEF...

ATTN...RFC...CBRFC...

LAT...LON   41950894 41170842 39490938 37901050 36011232 
            35811339 37131314 38241265 40161104 41571011