Graphic for MPD #0050

MESOSCALE PRECIPITATION DISCUSSION 0050
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
551 PM EST TUE FEB 14 2017

AREAS AFFECTED...OLYMPIC PENINSULA OF WA

CONCERNING...HEAVY RAINFALL

VALID 142250Z - 151050Z

SUMMARY...RAINFALL RATES APPROACHING AND EXCEEDING 0.5 IN/HR ARE
EXPECTED TO REACH THE OLYMPICS NEAR 06Z TONIGHT. THIS IS EXPECTED
TO BE THE START OF A LONGER DURATION HEAVY RAINFALL EVENT FOR THE
REGION...EXPECTED TO LAST INTO WED NIGHT.

DISCUSSION...AT 22Z...A COLD FRONT WAS ANALYZED THROUGH THE ERN
PACIFIC...350-400 MI WEST OF THE WA COAST...ORIENTED NNE TO SSW.
BLENDED TPW IMAGERY SHOWED AN ATMOSPHERIC RIVER CONTAINING A
NEARLY CONTINUOUS AXIS OF 1.5+ INCH PRECIPITABLE WATER VALUES
EXTENDING FROM NEAR 130W TO THE TROPICAL WEST PACIFIC. THE FRONT
WAS LOCATED AHEAD OF A LONGWAVE MID-UPPER LEVEL TROUGH AXIS
APPROACHING THE WEST COAST...WITH A POWERFUL 150-170 KT JET
LOCATED IN THE BASE OF THE TROUGH NEAR 35N 150W. WEAKER BUT
PERHAPS NOTEWORTHY JET STREAKS EJECTING OUT FROM THE MAIN JET AXIS
WILL CONTINUE TO ADVANCE TOWARD BRITISH COLUMBIA...AND AS THE
UPPER TROUGH AXIS EDGES CLOSER TONIGHT...MAY ALLOW ENHANCED LIFT
THROUGH ADDED UPPER DIFFLUENCE/DIVERGENCE ACROSS THE OLYMPIC
PENINSULA.

HI-RES MODELS INCLUDING THE NMMB...ARW...NAM_CONEST AND PARALLEL
NAM_CONEST HAVE BEEN TRENDING WETTER IN THE 06-12Z PERIOD ENDING
12Z WED MORNING. 850 MB WINDS ARE FORECAST TO BE FROM THE SSW AT
60-65 KT AND SHOULD BE CO-LOCATED WITH PRECIPITABLE WATER VALUES
APPROACHING 1.2 INCHES ALONG THE WA COAST BY 06Z. STANDARDIZED
ANOMALIES WITH THESE PRECIPITABLE WATER VALUES WOULD FALL IN THE
+3 TO +4 RANGE. TOTAL RAINFALL THROUGH 11Z SHOULD BE IN THE 2-3
INCH RANGE BUT LOCALLY HIGHER VALUES ARE POSSIBLE.

OTTO

ATTN...WFO...SEW...

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

LAT...LON   48202437 48002328 47612296 47152355 47132428
            47752463


Last Updated: 551 PM EST TUE FEB 14 2017