MESOSCALE PRECIPITATION DISCUSSION 0765
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
243 PM EDT SAT NOV 05 2016
 
AREAS AFFECTED...NWRN CA INTO SWRN OR 
 
CONCERNING...HEAVY RAINFALL 
 
VALID 051842Z - 060542Z
 
SUMMARY...A PERIOD OF HEAVY RAIN WILL IMPACT PORTIONS OF THE SRN
OR COASTAL RANGES INTO NWRN CA...WITH A POSSIBLE SURGE INTO NWRN
CA BETWEEN 00-03Z. RAIN RATES SHOULD SIGNIFICANTLY DIMINISH AFTER
06Z.

DISCUSSION...WATER VAPOR IMAGERY AS OF 18Z SHOWED A VORTICITY MAX
CENTERED NEAR 34N 133W WITH A WELL DEFINED TROUGH AXIS EXTENDING
NORTH AND SOUTH. THE ONGOING STRONGEST MOISTURE FLUX INTO THE
COAST OF OR HAS SHOWN OBSERVED RAINFALL RATES BETWEEN 0.3 TO 0.4
IN/HR WITH LOCALLY HIGHER RATES POSSIBLE BETWEEN OBSERVING
STATIONS. BLENDED TPW IMAGERY SHOWED PWATS PEAKING NEAR 1.5 INCHES
50-100 MI WEST OF THE NRN CA COAST BUT GPS SITES HAVE BEEN MAXING
OUT IN THE 1.2 TO 1.3 INCH RANGE ALONG THE OR COAST COINCIDENT
WITH A PACIFIC COLD FRONT WHICH WAS MOVING INLAND AS OF 18Z.
INFRARED IMAGERY AND THE GOES HD WIND PRODUCT SHOWED A 120-140 KT
UPPER LEVEL JET STREAK POINTED ACROSS VANCOUVER ISLAND AS OF 18Z.

THE JET STREAK IS FORECAST BY A CONSENSUS OF THE LATEST GUIDANCE
TO CONTINUE LIFTING NEWD...WITH THE ASSOCIATED RIGHT ENTRANCE
REGION DIVERGENCE WEAKENING AS THE TAIL END OF THE JET STREAK
REACHES THE OR/CA BORDER AROUND 00Z. AS THE SHORTWAVE TROUGH
IDENTIFIED NEAR 133W NEARS THE OR/NRN CA COAST BY 00Z...SOME
NEGATIVE TILT IS EXPECTED WITH ENHANCED UPPER DIFFLUENCE AHEAD OF
THE FEATURE. 850-700 MB FLOW WILL CONTINUE TO BE FROM THE SSW INTO
THE MPD THREAT AREA WITH A MAGNITUDE PEAKING IN THE 30-40 KT
RANGE...SIMILAR TO THE ONGOING WIND MAGNITUDE. GIVEN THE LEVEL OF
MOISTURE WITHIN THE PWAT PLUME AND UPCOMING JET
DYNAMICS...RAINFALL RATES PEAKING NEAR 0.5 IN/HR ARE EXPECTED
INITIALLY ALONG THE SWRN OR COAST...TRANSLATING SWD INTO NRN CA
TOWARD 00Z. THE APPROACHING SHORTWAVE SHOULD BE TIED TO A SLIGHT
SURGE IN RAINFALL INTENSITY...EXPECTED TO PEAK IN THE 00-03Z TIME
FRAME ACROSS NWRN CA. RAINFALL INTENSITY IS EXPECTED TO GREATLY
DIMINISH WITH THE FRONTAL PASSAGE AFTER 06Z.

OTTO

ATTN...WFO...EKA...MFR...PQR...STO...

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

LAT...LON   43712273 43562246 43152215 42522211 42132211 
            41632205 41302223 40972271 40662296 40352296 
            39932288 39562300 39312373 39562426 40432470 
            41552457 42012462 42362464 42592457 42812443 
            42982406 42982370 43102346 43292329 43482312