MESOSCALE PRECIPITATION DISCUSSION 0757
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
845 AM EDT FRI OCT 28 2016
 
AREAS AFFECTED...CENTRAL SIERRAS OF CA...NORTHERN NV...EXT
SOUTHWEST ID 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 281245Z - 282145Z
 
SUMMARY...STATIONARY DEFORMATION ZONE ALLOWS FOR PERSISTENT
CHANNEL OF MODERATE TO HEAVY RAINFALL ACROSS CENTRAL SIERRAS
THROUGH NORTHERN NEVADA. 

DISCUSSION...PLEASE REFER TO MPD 756 FOR COASTAL AND CENTRAL
VALLEY OF CA RAINFALL THREAT.

WV LOOP SHOWS WELL DEFINED CLOSED DEEP UPPER LOW JUST OFF CENTRAL
CA COAST WITH DEEP MOISTURE CHANNEL NOW CROSSING THE TRANSVERSE
RANGES OF S CA TOWARD THE S CENTRAL SIERRAS AND VEERING ACROSS
INTO W CENTRAL NV ATTM.  A DEEPLY SATURATED VERTICAL PROFILE
EXISTS NEAR AND NORTH OF A STATIONARY FRONT AND DEEP DEFORMATION
ZONE SAN FRAN BAY ACROSS TO LAKE TAHOE AND INTO NE NV. SURFACE TDS
IN THE MID 50S AND 12Z REV RAOB INDICATES A DAILY RECORD TPW OF
.85" WELL EXCEEDING THE PRIOR VALUE OF  .67" AND NEARS THE ALL
TIME OCTOBER RECORD OF .89"...WELL OVER 3-4 STD DEV FROM NORMAL. 

GIVEN ORIENTATION OF UPPER LOW TRACK TOWARD NORTHEAST...THE
DEFORMATION ZONE/FRONTAL ZONE SHOULD REMAIN STATIONARY THROUGHOUT
THE DAY PROVIDING A PERSISTENT SATURATED CHANNEL AS WELL AS AMPLE
FORCING TO MAINTAIN MODERATE SHOWERS THROUGHOUT THE DAY.  LARGE
DIFFLUENT SPREAD ALOFT INTO THE RIGHT ENTRANCE OF A STRENGTHENING
110 KT 3H JET ALONG WITH HEIGHT FALLS CROSSING THE HIGHER TERRAIN
WITH DPVA/VORTICAL STRETCHING SHOULD STRENGTHEN ASCENT THROUGH THE
18Z-21Z TIME PERIOD CROSSING THE SIERRAS AS THE UL TRANSITIONS
ACROSS IT AND DOWNSTREAM THEREAFTER.  THOUGH THE WAVE WILL BEGIN
TO FILL/SHEAR AS IT CROSSES THE GREAT BASIN REGION...DEEP ASCENT
WILL REMAIN PRESENT THROUGHOUT FRIDAY TO ALLOW FOR RAINFALL TOTALS
TO COMPOUND SLOWLY. 

THOUGH THE SIERRAS WILL REDUCE THE AMOUNT OF AVAILABLE MOISTURE
FOR THE HIGHER RAIN RATES EXPECTED ON THE WINDWARD SIDE...RATES OF
.10-.25"/HR WITH ISOLATED POSSIBLE HIGHER SHORT TERM RATES WITH
THE MAXIMIZED FORCING TOWARD THE END OF THE EVENT AS WELL AS
FAVORED OROGRAPHIC REGIONS.   THIS WILL POSE A REGIONALLY HEAVY
RAINFALL EVENT WITH 24HR TOTALS AROUND 1-1.25"...LIKELY HIGHER UP
TO 2" WITHIN OROGRAPHICALLY FAVORED WHICH MAY CAUSE
PONDING/FLOODING IN LOWER FLAT AREAS AND POSSIBLE MUD/DEBRIS FLOWS
IN COMPLEX TERRAIN ACROSS N NV. 

GALLINA

ATTN...WFO...BOI...HNX...LKN...REV...STO...

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

LAT...LON   42551477 41721445 40551540 39951637 39141754 
            37801871 37511952 37722007 38382068 39072104 
            39702079 40811979 41671818 42491631