Quantitative Precipitation Forecast
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FOUS30 KWBC 110045
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
744 PM EST TUE JAN 10 2017

...VALID 01Z WED JAN 11 2017 - 12Z WED JAN 11 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
65 WSW CEC 55 WSW CEC 20 NNW CEC 35 ENE CEC 45 ESE CEC
20 NW O54 20 ENE O54 25 NNW RDD 35 NE RDD 40 NNE CIC 30 ENE OVE
25 SW TVL 35 NE FAT 25 NNE PTV 25 ENE BFL 25 NE BFL HJO
10 WSW FAT 20 WSW MAE 45 E SNS 15 NE PRB 30 NE SMX 30 W SDB 3A6
20 ESE SBA 15 SSW SBA 25 S LPC 80 WSW VBG.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
75 SW O87 10 S O87 35 SSE ACV 30 NNE ACV 30 E CEC 30 ENE ACV
35 E O87 25 N UKI 10 NE STS 15 NW APC CCR LVK 20 ESE RHV WVI SNS
35 SSE SNS 15 N SBP 15 ESE SBP 15 SSW SBP 25 WSW SBP 40 SSW 87Q
45 WSW 87Q 70 WSW MRY.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 WSW AUN OVE 10 S CIC CIC 10 NE CIC 15 E CIC 15 NNE OVE
20 NE BAB 15 N AUN 20 SE AUN 45 ESE MHR 35 NE MCE 20 ENE MCE
30 NE SCK 15 WSW AUN.


0100 UTC UPDATE...

ONLY MINOR CHANGES MADE TO PREVIOUS OUTLOOK AREA..TRIMMING BOTH
SLIGHT AND MARGINAL AREAS ACRS NW CA WITH PASSAGE OF COLD FRONT
WHICH WILL ALLOW SNOW LEVELS TO GRADUALLY FALL ACRS THE SISKIYOUS
WITH POST FRONTAL SHOWERS BEING MORE TIED TO TOPOGRAPHY THERE.
OTHERWISE...MAIN BAROCLINIC MSTR BNDRY WILL CONTINUE TO SHIFT SWD
OVERNIGHT WITH DECENT UPSLOPE INTO THE NRN/CNTL SIERRA CONTINUING
AS WELL AS THE COASTAL RANGES SOUTH OF MONTEREY BASED ON RECENT
BLENDED TPW DATA WHICH SHOWS HIEST AXIS OF PW AOA 1.25 INCHES
FOCUSED INTO THAT REGION EARLY IN THE PD BEFORE SETTLING SWD LATER
TONIGHT.  SULLIVAN
PREVIOUS DISCUSSION FOLLOWS...


...SW OREGON AND NRN TO CENTRAL CA...

THE BULK OF MODEL AND ENSEMBLE GUIDANCE OFFERS REASONABLY
COMPATIBLE MASS FIELD GUIDANCE...ALBEIT WITH SOME EMBEDDED IMPULSE
TIMING DIFFERENCES WITH A SERIES OF DYNAMIC SHORTWAVE IMPULSES
POISED TO MOVE INLAND FROM THE EPAC IN PROGRESSIVE BUT AMPLIFYING
FLOW. THE APPROACH OF A NEW SURGE OF DEEPER PACIFIC MOISTURE AND
JET ENERGY WILL INCREASE THE COVERAGE AND INTENSITY OF
PRECIPITATION. BLENDED PRECIPITABLE WATER LOOPS AND A BLEND OF
RECENT GFS/ECMWF RUNS COMBINE TO SHOW AMPLE POTENTIAL FOR ANOTHER
SIGNIFICANT ROUND OF UNSETTLED WEATHER AND WIDESPREAD HEAVY
PRECIPITATION AS HEIGHT FALLS AND A DEEPENING SURFACE LOW MOVES
INTO THE CA COAST. ANOTHER ATMOSPHERIC RIVER EVENT ON TAP WILL
FUEL WIDESPREAD HEAVY PRECIP WITH HEAVIEST TOTALS FROM SW OREGON
SOUTHWARD THROUGH THE NRN TO CENTRAL CA COAST RANGE AND INTO THE
SIERRA. WIDESPREAD AREAL AVERAGE 2-4" AMOUNTS ARE POSSIBLE WITH
LOCAL TERRAIN ENHANCED AMOUNTS IN THE 5-8" RANGE POSSIBLE FOR THE
CENTRAL TO NRN SIERRA AND NRN CA COASTAL RANGE. ADDITIONAL RUNOFF
ISSUES REMAIN LIKELY ACROSS THESE AREAS THAT HAVE BEEN IMPACTED BY
HEAVY PRECIP OVER THE PAST FEW DAYS. THE ARRIVAL OF COLDER AIR IN
THE WAKE OF THE MOST RECENT STORMS WILL LIMIT THREAT COVERAGE AWAY
FROM HIGHER TERRAIN DUE TO LOWERED SNOW LEVELS.

SCHICHTEL
$$





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