Quantitative Precipitation Forecast
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FOUS30 KWBC 311349
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
848 AM EST SUN JAN 31 2016

...VALID 15Z SUN JAN 31 2016 - 12Z MON FEB 01 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 SW PSP 10 NNE CZZ 15 S CZZ 10 SSE MMTJ 10 WSW NRS 15 WSW OKB
10 SSW SLI 10 SW LAX 25 SSE SBA 25 WSW SBA 10 SW XVW 10 SW SBP
20 SW PRB 10 N PRB 20 E PRB 40 NE SMX 30 SSW BFL 15 SE BFL
10 NNE PTV 30 ESE PTV 20 W MHV 10 WSW PMD 15 SE PMD 30 NNE ONT
30 NW PSP 25 SW PSP.


15Z UPDATE...
NO CHANGE TO PREVIOUS FORECAST AREA OR REASONING FOR SOUTHERN CA.
EXPECT PCPN RATES TO BEGIN TO PICK UP ACRS SRN CA OVER THE NEXT
SEVERAL HOURS WITH APCHG LOW PRES RIDING ALONG QSNTRY FRONTAL
BNDRY.  SEE MPD#24 FOR FURTHER DETAILS.   SULLIVAN
PREVIOUS DISCUSSION FOLLOWS.


...SOUTHERN CA...


HEAVY UPSLOPE RAINS ARE EXPECTED FOR SOUTHERN CA AS SHORTWAVE
ENERGY OFFSHORE THE WEST COAST DIGS SOUTHEAST AND BEGINS TO
AMPLIFY OVER THE REGION BY LATER SUN. THE GUIDANCE SHOWS AN
EXTENSION OF THE SURFACE LOW DEVELOPING OVER SOUTHERN CA EXTENDING
OFFSHORE AND COINCIDING WITH A COLD FRONT DROPPING SOUTH DOWN THE
COAST. A POOL OF 0.75 TO 1 INCH PWATS IS EXPECTED TO ARRIVE ACROSS
THE SOUTHERN CA COASTAL RANGES SUN AFTERNOON AND EVENING AS THE
FRONT ARRIVES...AND A CONSENSUS OF THE GFS AND ECMWF SOLUTIONS
SUGGESTS A 30 TO 40 KT SOUTHWESTERLY LOW LEVEL JET AIMING INTO THE
HIGHER TERRAIN...WITH A PARTICULAR FOCUS ON THE SAN GABRIEL AND
SAN BERNADINO MOUNTAINS. THIS WILL ENHANCE PRECIPITATION RATES AND
IN FACT THE 00Z GFS SHOWS 850/700 MB MOISTURE FLUX ANOMALIES
REACHING OVER 5 STANDARD DEVIATIONS ABOVE NORMAL BY 00Z MON OVER
THIS REGION. HEAVY RAINS OF GENERALLY 1 TO 2 INCHES ARE EXPECTED
OVER THE SOUTHERN CA COASTAL RANGES...HOWEVER...ISOLATED AMOUNTS
OF 2 TO 4 INCHES ARE EXPECTED WHERE UPSLOPE FLOW/MOISTURE FLUX IS
MAXIMIZED. THIS WILL DRIVE SOME CONCERNS FOR FLASH FLOODING
LOCALLY...WITH THE POTENTIAL FOR DEBRIS FLOWS AND MUDSLIDES. ANY
BURN SCAR AREAS WILL SEE THE HIGHEST POTENTIAL FOR THESE HAZARDS.

ORRISON
$$





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