MESOSCALE PRECIPITATION DISCUSSION 0042
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
125 PM EST SAT MAR 05 2016
 
AREAS AFFECTED...CENTRAL CALIFORNIA COAST 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 051830Z - 060330Z
 
SUMMARY...SUBTROPICAL STREAM OF MOISTURE AND EMBEDDED WAVE TO
AFFECT CENTRAL COASTLINE WITH MODERATE TO HEAVY RAINFALL MAINLY IN
SW FACING OROGRAPHY 

DISCUSSION...BLENDED TPW HAS A BIT OF REDUCTION WITH A PASS JUST
OFF THE W COAST OF CALIFORNIA...SO AN AMSU PASS WITH VALUES IN THE
1.3-1.5" RANGE CAN BE SEEN NEAR A WEAK SURFACE WAVE/CONVERGENCE
ZONE IN THE SUBTROPICAL STREAM JUST NORTH OF 30N EAST OF 130W THAT
IS ALREADY STARTING TO ENHANCE FROM THE APPROACHING HEIGHT FALLS
AND AMPLIFICATION SEEN IN THE POLAR WAVE COLD FRONT (DISCUSSED
MORE IN DETAIL IN MPD0041).  VISIBLE LOOP SHOWS A BIT OF AGITATION
IN THE CLOUD FIELD OUT NEAR THIS REGION...BUT ALSO AN EXTENSION OF
THE BOUNDARY/NEAR SURFACE CU FIELD EXTENDING E TOWARD THE NORTHERN
CHANNEL ISLANDS.  THIS MATCHES UP WITH RECENT ENHANCED BOUNDARY
SEEN IN AMSU 89GHZ IMAGERY.  ALOFT WV INDICATES THE SUBTROPICAL
JET RIDGE SHIFTING SE INCREASING THE DIFFLUENCE FOR INCREASING
UVVS FOR INCREASED SHOWERS.  HI-RES GUIDANCE ARW/NMMB/HRRR ALL
INDICATE THIS UPWARD TREND THAT WILL BE TRANSPORTED ON SWLY LOW
LEVEL FLOW TOWARD THE CENTRAL CA COAST.  CURRENT TRACKING FROM
SATELLITE IMAGERY SEEMS TO BARE OUT THE TIMING IN THE MODELS AS
WELL FOCUSED AROUND 21Z...MAINLY IN THE COASTAL TERRAIN SOUTH OF
MONTERREY BAY.  THIS PRE-CURSORY .25"/HR RATES WILL CONTINUE UNTIL
THE FIRST LINE ASSOCIATED WITH THE SUBTROPICAL WAVE STARTS
AFFECTING THE CENTRAL COAST FROM SAN FRANCISCO BAY AT 22-23Z. 
THIS LINE WILL SHIFT SOUTHWARD TOWARD THE MONTERREY BAY AND SOUTH
TOWARD 01-03Z. EMBEDDED SHALLOW BUT EFFICIENT CONVECTION WITH
RATES UP TO .5"/HR MAY ENHANCE TO .75"/HR WITH ADDITIONAL
OROGRAPHIC ASCENT ON 45-50KT SWLY 850MB FLOW.  TOTALS THROUGH THIS
LINE ACROSS THE COASTAL MOUNTAINS OF MONTERREY/SAN LUIS OBISPO
COUNTIES LIKELY TO REACH 3" AND COULD EXCEED 4"...WITH THE
UPSTREAM POLAR FRONT STILL TO APPROACH BY 06Z.   

GALLINA

ATTN...WFO...HNX...LOX...MTR...STO...

ATTN...RFC...CNRFC...

LAT...LON   37972199 37772100 36462027 35591967 34971992 
            34822042 35032089 36402195 37602263