MESOSCALE PRECIPITATION DISCUSSION 0085
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
404 AM EDT SUN MAR 13 2016
 
AREAS AFFECTED...SW OREGON...NW CALIFORNIA 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 130800Z - 132000Z
 
SUMMARY...PROLONGED MDT RAINFALL PRECURSORY TO ENHANCED SWLY FLOW
AHEAD OF COLD FRONT TO RAISE RATES UP TO .5"/HR. 

DISCUSSION...PERSISTENT ONSHORE 30-40KT SWLY FLOW PER VWP
CONTINUES TO PRODUCE AVERAGE .1-.25"/HR RAIN TOTALS ALONG SW
FACING OROGRAPHY GIVEN SLIGHTLY INCREASING TPWS ALREADY NEAR 1.0"
ANALYZED NEAR CAPE MENDOCINO...LEADING A MODERATELY BROAD E-W
ORIENTED CHANNEL OF ENHANCED MOISTURE WELL PAST THE DATELINE JUST
SOUTH OF 40N. SIMILARLY ALOFT A VERY STRONG E-W JET CAN BE SEEN
WITH EMBEDDED RIPPLES ALONG IT.  PER AMSU MOSAIC AND GOES-W WV/IR
ONE OF THE RIPPLES IS STARTING TO ENHANCE WITH  BAROCLINIC LEAF
STRUCTURE FORMING NEAR 130W ASSOCIATED WITH AMPLIFYING SHORTWAVE
AND DEEPENING SURFACE REFLECTION. THE UPPER LEVEL JET WILL BE
INCREASING TO 130+KTS WITH A SLIGHT SOUTHEASTWARD ORIENTATION
NEARING THE COAST...PROVIDING EXCELLENT LEFT EXIT ASCENT TO
FURTHER DEEPENING SHORTWAVE/SURFACE REFLECTION.  GIVEN THESE
STRONG PRESSURE FALLS...LOW LEVEL WIND ENVIRONMENT IN THE BEST
OROGRAPHIC ASCENT LAYER BETWEEN 850-7H WILL STEADILY INCREASE AND
REACH NEAR 60 KTS AT 850...70+ AT 7H ABOUT 15-18Z ACROSS SW
OREGON.  STRONGER NORTH AND SLIGHTLY LOWER TO 40-50KTS ACROSS N
CA...ALONG THE NORTHERN EDGE OF BEST MOISTURE (OVER 1")...SO WITH
THE TRADE OFF...SWLY FACING OROGRAPHY WILL SEE SIMILAR TREND OF
RATES ACROSS MUCH OF THE DISCUSSION AREA FROM .25"/HR TO .5"/HR. 
THIS IS OF GREATEST CONCERN FOR FLOODING WITH SATURATED AREAS
WHERE 7 DAY TOTALS ARE EXCEEDING 3-6 TIMES THE NORMAL MAINLY FROM
COOS COUNTY SOUTHWARD.   

GALLINA

ATTN...WFO...EKA...MFR...MTR...STO...

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

LAT...LON   43392389 43282363 43142345 42722341 42472326 
            42322293 41792250 41482235 40992246 40652254 
            40352289 39582293 39082282 38692302 38712341 
            38912374 39432385 39902406 40352461 40712434 
            41292432 41972434 42562456 43022458 43262439