MESOSCALE PRECIPITATION DISCUSSION 0179
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
518 PM EDT THU MAY 05 2016
 
AREAS AFFECTED...NRN CALIFORNIA INTO S 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 052117Z - 060230Z
 
SUMMARY...SCATTERED...SLOW MOVING THUNDERSTORMS WILL POSE A FLASH
FLOOD THREAT ACROSS THE MORE VULNERABLE AREAS OF NRN CALIFORNIA
INTO SRN OREGON THROUGH LATE EVENING. SCATTERED RAINFALL RATES OF
1 IN/HR ARE EXPECTED.

DISCUSSION...WATER VAPOR IMAGERY NUMEROUS MESOSCALE VORTICITY
MAXIMA ROTATING NWD ALONG THE EAST SIDE OF AN ANOMALOUS UPPER LOW
CENTERED OFF OF THE CNTRL CALIFORNIA COAST. UPPER LEVEL FLOW WAS
FAIRLY DIFFLUENT ACROSS NRN CALIFORNIA AND THE LATEST BLENDED TPW
IMAGERY COMBINED WITH GPS SITE DATA SHOWED ANOMALOUS PRECIPITABLE
WATER IN PLACE WITH VALUES BETWEEN 0.9 AND 1.1 INCHES ALONG THE
NWRN CALIFORNIA COAST AND INTO THE NRN SACRAMENTO VALLEY. KBBX
RADAR IMAGERY HAS ALREADY SHOWN A FEW SLOW MOVING THUNDERSTORMS IN
THE VALLEY AND KLAMATH MOUNTAINS MOVING TOWARD THE NW AT 5-10 KTS.
STORMS ARE NOT VERY ORGANIZED GIVEN WEAK LOW TO MID LEVEL FLOW BUT
VERTICAL PROFILES ARE MOIST AND CLEAR SKIES EARLIER IN THE DAY
HAVE ALLOWED MLCAPE OF 500-1000 J/KG TO DEVELOP OVER NWRN
CALIFORNIA.

SLOW MOVEMENT OF THE UPPER LOW SHOULD CONTINUE TO ALLOW ADDITIONAL
THUNDERSTORM DEVELOPMENT INTO PORTIONS OF THE NRN SACRAMENTO
VALLEY AND INTO THE HIGHER TERRAIN OF NRN CALIFORNIA AND UPSLOPE
REGIONS OF THE SRN OREGON CASCADES THROUGH THE REMAINDER OF THE
EVENING. WHILE INDIVIDUAL THUNDERSTORM LIFE CYCLES SHOULD BE
SOMEWHAT SHORT LIVED GIVEN POOR SPEED SHEAR IN PLACE...POTENTIAL
RUNOFF ISSUES ALONG BURN SCARS AND WITHIN FLASH FLOOD GUIDANCE
VALUES...1 INCH OR LESS IN 1 HOUR...WILL BE POSSIBLE ON A
SCATTERED BASIS THROUGH THE REMAINDER OF THE EVENING.

OTTO

ATTN...WFO...EKA...MFR...MTR...PDT...PQR...REV...STO...

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

LAT...LON   43642231 43622149 42892128 42242071 41812045 
            41002020 40562042 40032099 39842140 39482154 
            39162146 38812150 38572170 38412198 38232225 
            38182278 38312301 39052373 40332442 41152443 
            41802428 42202372 42712313