MESOSCALE PRECIPITATION DISCUSSION 0540
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
833 PM EDT THU OCT 01 2015
 
AREAS AFFECTED...N NEVADA...SW IDAHO...NW UTAH 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 020031Z - 020631Z
 
SUMMARY...STRONG DYNAMICS WITH UNSEASONABLE MOISTURE AVAILABILITY
TO ALLOW FOR POTENTIAL FOR MODERATE TOTALS IN VICINITY OF LOW
FLASH FLOOD GUIDANCE

DISCUSSION...VERY STRONG SPEED MAX AND ASSOCIATED VORT ROUNDING
THE BASE OF THE LARGER SCALE TROF WHILE DISTANT FROM NORTHERN
STREAM ENERGY ALLOW FOR COL IN THE UPPER TROF WITH S/W RIDGING
WITH BACKING UPPER LEVEL FLOW IN ACROSS NE NV/SW ID.  THIS
SUPPORTS STRONG CYCLONIC DEVELOPMENT AT THE SURFACE WITH
STRENGTHENING LOW LEVEL FIELDS FOR INCREASED CONVERGENCE ALONG THE
FRONTAL ZONE AND ALONG OROGRAPHY.  COOLING ALOFT STEEPENS LAPSE
RATES TO SUPPORT MUCAPES IN THE 500-1000 J/KG FOR CONVECTIVE
DEVELOPMENT.  TPWS INDICATED IN BLENDED TPW AND GOES SOUNDER ARE
NOT IMPRESSIVE BY MOST STANDARDS AT .75"...BUT ARE NEARLY 3
STANDARD DEVIATIONS ABOVE NORMAL...CAPABLE OF EXCEEDING THE LOW
FLASH FLOOD GUIDANCE...THOUGH THE CORES SHOULD BE NARROW AND SMALL
THAT FLASH FLOODING THREAT SHOULD BE ISOLATED.  

VISIBLE IMAGERY AND LIGHTNING DETECTION NETWORK SHOW THESE NEW
CELLS SPROUTING WITHIN LANDER/EUREKA AND ELKO COUNTIES.  OVER THE
NEXT FEW HOURS AS THE STRONG VORT LOBE SHIFTS EAST...THE CELL
MOTIONS AND CORFIDI VECTORS REDUCE IN TO NEAR ZERO TO 10KT
RANGE...AND THE POTENTIAL FOR A PIVOT OF THE NORTHERN PORTION OF
THE UPPER LOW  OVER N NV AND KEEP THE DEFORMATION CHANNEL ACROSS
SW ID ACTIVE WITH MODERATE RAINFALL...WITH THE INSTABILITIES
EXHAUSTED RAINFALL WILL BECOME MORE STRATIFORM IN NATURE GIVEN
CONTINUED UPPER-LEVEL DIVERGENCE AND PVA.  HI-RES CAMS HAVE STRONG
AGREEMENT AS THE SSEO MEAN EVEN INDICATES 6HR TOTALS IN EXCESS OF
1" AND THE SPC-WRF/NAM CONEST AND HRRR ALL INDICATING TOTALS AOA
2" IN THE SAME TIME PERIOD.   

GALLINA

ATTN...WFO...BOI...LKN...PIH...REV...SLC...VEF...

ATTN...RFC...CBRFC...CNRFC...NWRFC...

LAT...LON   43431616 43171511 42611415 41851378 39521421 
            38971525 38691634 38241823 39271912 40591851 
            41671819 42761753